Download Proceedings of the 1st International Conference on Industrialised

Proceedings of the
1st International Conference on
Industrialised, Integrated, Intelligent
Construction (I3CON)
Loughborough, UK, 14-16 May 2008
Edited by Tarek Hassan and Jilin Ye
Proceedings of the
1st International Conference on
Industrialised, Integrated, Intelligent
Construction (I3CON)
Loughborough, UK, 14-16 May 2008
Organised by
• Loughborough University, UK
• Industrialised, Integrated, Intelligent Construction – Project co-funded by the European
Commission within the Sixth Framework Programme (FP6) under the Nanosciences,
Nanotechnologies, Materials and New Production Technologies (NMP) priority
Supported by
• BSRIA Limited, UK
• European Construction Technology Platform (ECTP)
Conference Organisation & Administration
Editors:
Dr Tarek Hassan
Dr Jilin Ye
Department of Civil & Building Engineering
Loughborough University
Leicestershire
LE11 3TU
United Kingdom
Tel: +44(0)1509 222602
[email protected]
Department of Civil & Building Engineering
Loughborough University
Leicestershire
LE11 3TU
United Kingdom
Tel: +44(0)1509 228741
[email protected]
Local Organising Committee:
•
•
•
•
•
•
•
•
Dr Jilin Ye, Loughborough University
Chris Carter, Loughborough University
Mrs Pam Allen, Loughborough University
Dr Farid Fouchal, Loughborough University
Prof. Dennis Loveday, Loughborough University
Dr Rupert Soar, Loughborough University
Dr Tarek Hassan, Loughborough University
Mike Doig, BSRIA Limited
©2008 Copyright Loughborough University and all contributors.
ISBN 978-1-897911-32-7
Published by:
Loughborough University
Leicestershire
LE11 3TU
UK
Printed by:
Media Services
Loughborough University
Leicestershire
LE11 3TU
UK
Permission to copy all or portions of the proceedings must be obtained from the authors and
from Loughborough University, UK.
ii
Advisory/Programme Committee Members
•
Erkki Aalto, RAKLI, Finland
•
Hamid Asgari, Thales Research and Technology, UK
•
Tim Baugé, Thales Research and Technology, UK
•
Chris Carter, Loughborough University, UK
•
David Churcher, BSRIA Limited, UK
•
Almudena Fuster, EMVS, Spain
•
Alistair Gibb, Loughborough University, UK
•
Matti Hannus, Technical Research Centre of Finland, Finland
•
Tarek Hassan, Loughborough University, UK
•
Iris Karvonen, Technical Research Centre of Finland, Finland
•
Konstantinos Kessoudis, Ed. Züblin AG, Germany
•
Veijo Lappalainen, Technical Research Centre of Finland, Finland
•
Dennis Loveday, Loughborough University, UK
•
David Martin, Martin & Martin Associates Ltd. UK
•
Darren Morrant, EurExcel, UK
•
Jouko Pakanen, Helsinki University of Technology, Finland
•
Kalevi Piira, Technical Research Centre of Finland, Finland
•
Eino Rantala, Technology Agency of Finland, Finland
•
Sven Schimpf, University of Stuttgart, Germany
•
Miguel Segarra, Dragados, Spain
•
Colin Waugh, Thales Research and Technology, UK
•
Liza Wolfhart, University of Stuttgart, Germany
•
Jilin Ye, Loughborough University, UK
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iv
Preface
I am delighted to welcome you all to this conference – the first of its kind – on Industrialised
Integrated Intelligent Construction (I3CON), which is responding to the needs of industry,
clients and construction stakeholders at large:
• Industrialisation addresses the need to move from labour-intensive craft and batch
processes to factory-based automated manufacturing, facilitating the integration of
advanced technology solutions, which is currently not possible in a site-based
environment;
• Integration of embedded systems and building services within a building’s fabric –
together with the consolidation of the value chain – will lead to new, more effective
business models and enable full lifecycle understanding and analysis of ownership; and
• Embedded intelligence in buildings will result in smarter decision making based on policy
and operation control systems and – coupled with sensor awareness – will lead to
customised, high performance spaces that provide sustainable environments tailored to
users’ needs.
The I3CON conference has been designed to attract practitioners, researchers and academics
working in the three ‘I’s’, and provides an opportunity to present results from research and
industry-based projects, as well as network and develop ideas for further work related to these
three themes. The conference has attracted a wide audience (over 13 countries) and generated
interest in a number of leading-edge areas, resulting in a varied programme of workshops.
Where else could you rub shoulders with EC officers and termite experts?
I hope you will agree that the papers presented in the conference and the outcomes of the
workshops will contribute towards advancement beyond the state of the art in these areas.
I would like to thank all those who made this conference possible, particularly the European
Commission, which is one of the drivers behind this conference and partly funding the
I3CON project, the I3CON project partners, who have explored the boundaries of knowledge,
resulting in breakthroughs and, in particular, the Loughborough University team that has
relentlessly strived to ensure the event is a success.
I look forward to welcoming you all to Loughborough during this exciting event and wish you
an enjoyable time at the conference.
Tarek Hassan
I3CON Conference Chair
May 2008
v
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Table of Contents
Keynote Presentations
1
I3CON: Industrialised, Integrated, Intelligent Construction
3
A Future of Building Technologies: Globally Optimised-Locally Designed
5
Distributed Energy for Eco-towns
7
Section 1: Industrialised Construction
9
Design for Change; Flexibility Key Performance Indicators
11
Under What Conditions are “Industrialization” and “Integration” Useful Concepts in the
Building Sector?
23
Adaptable Futures: Setting the Agenda
35
Identifying New Construction Demands – A Stakeholder Requirement Analysis
45
Automatic Manufacturing of Unique Concrete Structures
59
Exploring the Types of Construction Cost Modelling for Industrialised Building System (IBS)
Projects in Malaysia
67
Evolutionary Modeling as a Mean of Mass-Customization for Industrialized Building Systems
-Two Cases Explored81
Energy-usage and CO2 Emission: How Unfired Clay Based Building Materials Development
in the UK Can Contribute
89
Future Directions for Building Services Technologies in Denmark
99
Technology Monitoring in Construction: a Concept for Internet Supported Identification of
Experts in the Definition of the Search Field for Technology Monitoring
109
Section 2: Advanced Application of Real-time Integrated Building
117
An Enterprise Architecture for Integrating Building Services
119
The I3CON Service Engineering Approach - A Modular Approach for Developing new
Construction Services
131
Real Time Building Information Service for Emergency Management
141
Towards a Reference Model for Building Lifecycle Performance Measurement
149
Business Innovation in Construction through Value Oriented Product/Service Offerings for
Living Buildings
159
vii
Application of Modelling Techniques in Buildings and Exploitation of BEMS
171
Section 3: Technologies for Intelligent Building Services
177
Use of Wireless Sensors in the Building Industry-Sensobyg
179
Wireless Sensor Networks for Information Provisioning for Facilities Management
189
Life Cycle Information of Buildings Supported by RFID Technologies
199
Construction Processes for the Digital ‘Trinity’
211
Beyond Biomimicry: What Termites Can Tell Us about Realizing the Living Building.
221
Acknowledgements. This research was supported by grants from the National Science
Foundation (USA) to JST and the Engineering and Physical Sciences Research Council (UK)
to RCS. We are also grateful to the National Museum of Namibia and the Ministry of
Agriculture of the Republic of Namibia, which provided logistical and technical support for
this work.
235
Simulation of Innovative Climate Control Strategies Using Passive Technologies
239
Automated Assessment of Buildings, based on the Deployment of Wireless Networks of
251
Sensors
Integrated Overall Building Services Systems Architecture
261
Integrated Building Information Service through Building Services Gateway
273
Customer Satisfaction with Maintenance Contracts: Examination of Key Performance
Indicators Used to Measure Customer Satisfaction with Mechanical & Electrical Maintenance
Contracts and the Level of Importance Placed on Them by the Customer
281
Section 4: Energy Efficiency
291
GENHEPI: Demonstration Programme for Low Energy Renovation
293
Towards an Automated Technique for Optimising the Design of Thermosyphon Solar
Water Heaters
303
Underground Thermal Energy Storage
for Efficient Heating and Cooling of Buildings
315
Section 5: Industrial Presentations
325
Totally Integrated Building Automation
327
High Energy Efficiency in Intelligent Housing Built through Integrated and Industrialised
Processes
337
The Multi Heat System
361
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Keynote Presentations
1
Keynote Presentations
2
The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
I3CON: Industrialised, Integrated, Intelligent Construction
Miguel José Segarra Martínez
DRAGADOS S.A.
R&D Directorate
Avda. de Tenerife 4 y 6
28700 San Sebastián de los Reyes (Madrid), Spain
[email protected]
Abstract
The I3CON technologies promise to deliver a transformation of the Construction
sector towards a business paradigm which is more beneficial to industry
stakeholders and end-users alike. However, it should be noticed that although
such I3CON technologies have proven extremely useful in other areas of industry
(automotive, aerospace, manufacturing, computing science and ICTs, etc.), its
application in the context of construction is not direct and, much work is to be
done (e.g. closing the gap between design, build and demolition phases and
planning for the lifecycle) until effective deployment of such technologies is
common place.
Once a technological breakthrough is achieved, it must be employed by its owner
as a differentiator from the rest of the market. This is another hurdle to pass. It is
very often that clients do not perceive advantage but risk and are reluctant to
change as the handicaps of introducing a new technology are varied: the client
view of innovation, outdated regulation, insurance cost and other problems make
difficult the road to industrial exploitation of R&D and can lead a company to
failure in marketing innovative business models for its products and services.
The technology change also brings society change. In this respect, new ways of
making construction mean new ways of doing business, new services to offer and
to be offered and, new relationships among stakeholders. The structural changes
needed to achieve this are not easily imbued in the corporate and societal culture
of the countries where we live.
Keywords: Industrialised construction, integrated construction, intelligent
construction
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Keynote Presentations
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
A Future of Building Technologies: Globally Optimised-Locally
Designed
Reijo Kohonen, Professor, Dr.Sci(Tech)
CEO, Global EcoSolutions Oy
Tekniikantie 12
Innopoli I Tower A, 5th Floor
FIN-02200 Espoo, Finland
Abstract
Construction is, in terms of employment and annual expenditures, one of Europe’s
largest industrial sectors. Further the building sector represents one of the major
contributors to energy use and greenhouse gas emissions. Energy use in buildings
accounts for around 45% of European. Building sectors is known as rather
conservative to adopt new technologies and practices. There are however a
number of drivers obliging the building industry to make a kind of paradigm
change in their offering and operations: climate change, shortage and cost of
skilled labour force; importance of individual values and requirements, health and
well-being, the world going to mobile etc.
Major changes seen by the author will be discussed in the presentation. These
changes are (in random order): from energy efficient to energy surplus
(autonomous) buildings; from standard solutions to mass customisation; from to
digital processes and operations; from partial optimisation to integrated design ;
from centralised to decentralised (individual); from craft and labour intense to
knowledge intense; from product to solution business ; from price driven to
performance driven. Very much the same issues was already addressed in the ECORE strategy document from 2005 and some of them are within the scope of the
i3CON project as well.
In the presentation it will be given rationale to how the foreseen paradigm
changes could be implemented in the terms of applying new technologies and
business models. . For instance, a solution to respond to the need for flexibility
e.g. easy re-configuration of spaces is illustrated through “webified” and
networked systems concepts. A kind of business- technology road maps will be
introduced to illustrate the short and longer term visions for:
• Life cycle performance buildings
• Passive / energy plus buildings and autonomous communities
• Building services
• ICT in the built environment
The concept of GOLD- globally optimised locally designed- will be explained
through a holistic concept of EcoCity and its design principles in some real cases.
5
Keynote Presentations
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Distributed Energy for Eco-towns
David Clarke
Energy Technologies Institute
Holywell Building, Holywell Way
Loughborough, LE11 3UZ, United Kingdom
www.energytechnologies.co.uk
Abstract
The Energy Technologies Institute is a public/private partnership, backed by
companies including BP, Caterpillar, EDF, E.ON, Rolls Royce and Shell. It was
set up in 2007 to play a key role in accelerating the achievement of energy and
climate change goals, through creating and managing a ten-year collaborative
programme of R&D, with a potential development fund of £1billion.
Based at Loughborough University, The ETI aims to bring together the best
scientists and engineers from industrial organisation and academia, UK and
overseas, to develop projects that will demonstrate a new range of technologies
which will increase energy efficiency and reduce carbon emissions. This year
there have been three calls for Expressions of Interest, in Marine, Offshore Wind
and Distributed Energy (DE) projects. More calls are planned, as part of an
intensive process of evaluating proposals, developing working consortia, and
allocating funds as projects progress.
DE may be of most interest to attendees at I3CON. The ETI can fund proposals
for local generation of power on a domestic or industrial scale, aimed at creating
energy from renewable sources such as the sun, wind or biomass. The projects
could have many applications – to the new eco-towns, or to the schools rebuilding
programme for example.
7
Keynote Presentations
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Section 1:
Industrialised Construction
9
Industrialised Construction
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Design for Change; Flexibility Key Performance Indicators
Rob P. Geraedts1
1
Delft University of Technology, Faculty of Architecture, Department of Real Estate & Housing, Berlageweg 1,
2628 CR Delft, [email protected]
Abstract.
With Flexibility Key Performance Indicators a detailed picture is obtained of the flexibility demanded or offered. They can
be used to judge the various flexibility aspects of existing buildings, but also to formulate the requirements with respect to
flexibility when new buildings are to be realized. Thus, these Indicators form a mean of communication on both the supply
and the demand side of the building market. This research is describing four key indicators for measuring the flexibility of
building installations: partitionability, adaptability, extendibility and multifunctionality. In order to assess the flexibility of
buildings or their components, each key indicator is divided into a number of sub aspects. For each sub aspect assessment
criteria are formulated leading to three possible ratings. Ratings multiplied by weighting factors give the different indicator
scores. Thus, a final judgement can be given to the overall flexibility of a building. Here too, weighting factors, scores and
flexibility classes have been developed.
Keywords
Open building, Sustainability, Flexibility Key Performance Indicators, Adaptability
1.
Introduction
Open Building provides strategies for consumer oriented and sustainable buildings, based on
specific principles and methods in programming, design, production planning, construction
and facility management. Open Building enables built environments to adjust, meeting
changing social, environmental and technical requirements.
Developments in the building sector show a number of trends all of which point to the
growing importance of flexibility in buildings and the installations concerned. In addition
there is the trend towards sustainable building. Environmental problems and energy
management are very much in the limelight. Adaptable, recyclable and sustainable buildings
will be major criteria in judging future buildings. Among the factors that play a role here are
saving of base materials, minimizing waste production, ease of dismantling and adaptability.
Clearly, flexible buildings that are readily adaptable to changing conditions respond to this
trend.
1.1 Vacancy of buildings
At this moment many buildings in the Netherlands like offices, churches, warehouses and old
industrial buildings are vacant because they no longer meet present requirements. It is
expected that in this sector there will be an increasing lack of occupancy in the coming years.
This tends to lead to demolition and new-construction projects and to considerable wastage.
Such activities not only involve a destruction of capital, but they also have an adverse effect
on the environment. What is needed to avoid vacancies is the possibility of adapting buildings
to the rapidly changing demands of users.
11
Industrialised Construction
1.2 Installations as a key factor
The technical installations are often found to be the key factor with respect to the possibilities
of adapting buildings. Installations in particular often prove not to be sufficiently flexible to
follow changes in their use without too many adaptations. Therefore Flexibility performance
indicators for installations could be regarded as a tool for assessing and discussing flexibility
of a building as a whole in a rapidly changing market.
The design of flexible installations in commercial, industrial and residential buildings is very
much an optimization problem, in which the building and the installations are inextricably
bound up with each other. For a ready adaptation to market fluctuations it would be desirable
to impose the condition that the building, along with its installations -in various combinationsshould be suitable for several uses. And this should be borne in mind already during the
development phase. The development of a vision with respect to the flexibility of a building,
or of a flexible-building concept, should therefore go hand in hand with the development of
an associated flexible-installation concept 1. In fact, it is recommended to integrate the design
of a building and that of the installations at the earliest possible stage. of development.
1.3 Costs and benefits of flexibility
Partly owing to the fact that so many parties are involved in the realization of a building and
its installations, budgeting for additional capital expenditure to ensure future flexibility is still
an exception. As a rule the party bearing the initial costs is not the one that reaps the possible
future benefits from alterations. Yet, when it comes to weighing alternative solutions, the
ultimate lifecycle costs are more important than the possible additional investments involved
in certain flexibility provisions. Alterations in buildings can become very expensive when no
flexible systems have been used. This is a fact of the utmost importance for the managers and
users of buildings. It calls not only for the incorporation of flexibility in both buildings and
their installations but also for another project organization. When the planning, the
implementation and the management of a project are in the hands of a single organization, it
suddenly does become possible to budget for additional capital expenditure to ensure
flexibility. For, in that case the cost and the possible future benefits remain in one hand.
The most interesting flexibility measures, obviously, are those involving no extra expenditure.
Their implementation will meet with little opposition in the field. Things are different when
additional expenditure is involved. It must be affordable in the first place. Unfortunately, the
financial advantages to be expected are often not all that obvious. An important factor in this
connection is the likelihood of the flexibility potential actually being utilized in the future. If
its use is uncertain, the benefits are equally uncertain.
In making a choice from among the various alternatives it is essential also to weigh the costs
against the future benefits. A calculation method for this purpose was developed in another
study 2. It takes into account the following items: maintenance costs, life expectancy and, in
budgeting, clustering of elements according to function and life, cost of adaptation and
benefits expected.
1
2
Geraedts R.P., Flexis (Flexibility of Installations), Dutch Building Research Foundation (SBR) and the Dutch Institute
for the Study and Stimulation of Research in the field of building installations (ISSO), SBR, Rotterdam, 1995
Geraedts R.P., Vermaas H., Wees L.J. van, Verkavelbare Dragers en Kosten (Partitionable Buildings and Costs), SBR 189,
Rotterdam, 1989
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
1.4 Sustainable building
Developments in the building sector show a number of trends all of which point to the
growing importance of flexibility in buildings and installations. In addition there is the trend
towards sustainable building. Environmental problems and energy management are very
much in the limelight. Sustainability will be a major criterion in judging future buildings and
their installations. Among the factors that play a role here are saving of base materials,
minimizing waste production, ease of dismantling, adaptability and deposit money
arrangements. Clearly, flexible buildings and installations that are readily adaptable to
changing conditions respond to this trend.
2
Levels or modularity
During the development of the Flexibility Key Performance Indicators (FKPI) the need was
felt of setting up a consistent system for the description and determination of the different
components in buildings and its installations. Open Building provides strategies for consumer
oriented and sustainable buildings. One of these strategies is the distinction between different
decision levels or modularity. Modularity refers to the various spatial levels at which the
building functions are in operation. Within the framework of FKPI two major levels are
distinguished: the local and the central level (see figure 1). The central level is the set of all
the levels higher than local. In a building these are a floor, a wing and the whole building.
Level 1
Unit
LOCAL
Level 2
Floor
Level 3
Wing
Level 4
Building
Level 5
City
CENTRAL
Fig. 1. Various levels at which installation functions can be offered: local or central
In general it can be concluded that the flexibility of a building is determined to a considerable
extent by the (spatial) level at which that particular function is offered or possible. For
example related to installations: can heating or cooling be made available per unit or per
floor? Thus, modularity is an important criterion in judging the flexibility of buildings 3.
Modularity can be system-bound. There are systems which by definition can be made
available only per unit at the infill level, for instance electrical or central-heating radiators.
Other systems are restricted to the central availability of functions at the skeleton level, such
as a common basic air-heating system.
3
Geraedts, R.P.: Costs and benefits of flexibility. In proceedings World Building Congress, Wellington, New Zealand
(2001)
13
Industrialised Construction
3
Flexibility Key Performance Indicators
The development of a vision with respect to the flexibility of a building, or of a flexiblebuilding concept, should go hand in hand with the development of an associated flexibleinstallation concept. In fact, it is recommended to integrate the design of a building and that of
the installations at the earliest possible stage of development.
The Flexibility Key Performance Indicators described in this research are not a well-defined
end product. They have a flexible set-up. They can be adapted to any changes in wishes, new
technology, criteria and views of user groups or clients. The indicators and the associated
flexibility criteria can be adapted, supplemented and extended according to the needs dictated
by the project or the client. The indicators will produce different results, depending on the
purpose for which it is used. Obviously, the flexibility requirements and criteria will vary
from user to user. The assessment of flexibility in a given situation will produce other results
than the formulation of flexibility for a future situation.
The Flexibility Key Performance Indicators can be used in communication, advice and
assessment with respect to the flexibility of buildings. The major objective is the realization
of flexible buildings. They form a tool for the specification of demands with respect to the
flexibility and for judging what is on offer. Thus it becomes possible to make full allowance
for any changes in the function of the building right from the start and throughout its use.
Four Key Performance Indicators
This flexibility tool distinguishes four Key Performance Indicators of the flexibility of
installations in buildings: partitionability, adaptability, extendibility and multifunctionality.
These aspects resulted from the clustering of 23 sub-aspects of flexibility (see figure 2). They
can be used to assess the flexibility of installations and of their components, if desired.
1
2
3
4
5
6
PARTITIONABLE
Partitionable
Collective/individual
Central/decentral
Disconnectible
Zonable
Modular
7
8
9
10
11
12
13
14
ADAPTABLE
Adaptable
Dismantable
Rearangeable
Adjustable
Exchangeable
Alterable
Mobile
Shapable
15
16
17
18
EXTENDIBLE
Extendible
(Over)Capacity
(Over)Dimensions
Ductless
19
20
21
22
23
MULTIFUNCTIONAL
Multifunctional
Intelligent
Automated
Universal
Integrated
Fig. 2. The four Flexibility Key Performance Indicators with different sub-aspects
Indicator 1: Partitionability
Partitionability is the possibility of splitting up, rearranging or combining installation systems
into different spatial units in a simple way. An important point in this connection is whether
distribution, conversion, supply (transfer) and the measurement or control of installation
functions take place locally or centrally. Another important aspect is a possible distinction
between the collective (support) and the individual (infill) mode of offering functions and the
zoning of distribution facilities.
Indicator 2: Adaptability
The adaptability of an installation is the possibility of altering installation systems in a simple
way to meet changes in the user's demands (the installation function required) resulting, for
14
The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
example, from a structural or functional rearrangement of the building, from changes in use,
the coming of other (groups of) users, or technological renewals and modernizations
considered necessary.
Indicator 3: Extendibility
Extendibility is the possibility of adapting installation systems in a simple way to additional
user demands, for instance by the addition of more or new installation components called for
by structural or functional extensions, both inside and outside the existing building.
Indicator 4: Multifunctionality
Multifunctionality is the possibility of using or deploying installation systems or components
for several functions. This allows of a more efficient use of space and permits clustering and
concentration of installation components. This concept is sometimes also called integration.
4
Assessment of flexibility
In order to judge the flexibility of buildings or their components, each flexibility indicator is
divided into a number of sub indicators (see figure 3). To determine the degree of
partitionability, use is made of the parameters for distribution (supply and removal),
conversion (central unit or supply system), transfer (of installation functions), measurement
(consumption) and control (use). To determine the degree of adaptability the following sub
indicators are judged: disconnectibility of the various installation components (plug-in
connections), the accessibility of components (distribution networks, zoning) and the
adjustability of measurement and control facilities in particular. To determine the degree of
extendibility the following sub indicators are judged: the capacity and dimensions of
installation facilities for distribution, conversion (central unit), measurement and control, and
the location and structure of distribution networks. Finally, to determine the degree of
multifunctionality the following sub indicators are judged: the number of integrated functions
in distribution facilities and in facilities for supply, use, measurement and control. Besides,
the extent to which the various components are universal (project-independent) is judged.
1
2
3
4
5
6
PARTITIONABLE
Distribution (supply)
Distribution (removal)
Conversion (central unit)
Transfer (functions)
Measurement
Control
ADAPTABLE
1 Disconnectible
2 Accessible
3 Adjustable
1
2
3
4
EXTENDIBLE
Capacity (local)
Capacity (central)
Dimensions (distribution)
Location (shafts)
MULTIFUNCTIONAL
1 Integration (functions)
2 Universal (components)
Fig. 3. Sub indicators used in judging the flexibility of an installations
4.1 Judging partitionability
The diagram below shows what is meant by the assessment criteria for the flexibility indicator
called partitionability (figure 4). It comprises the sub aspects of partitionability introduced
earlier: distribution (supply and removal), conversion (central unit or supply facility), transfer
(of installation functions), measurement (consumption) and control (use).
15
Industrialised Construction
ASSESSMENT OF PARTITIONABILITY
Rating
DISTRIBUTION
(Supply)
No distribution network (supply)
Generic distibution (power, gas, oil)
Specific distribution (hot water, air)
3
2
1
DISTRIBUTION
(Removal)
No removal network
Local removal network (at unit level)
Central removal network (at central level)
3
2
1
X
3
=
CONVERSION
(Supply)
No conversion (only at city/district level)
Local conversion (at unit level)
Central conversion (at central level)
3
2
1
X
2
=
TRANSFER
(Installation
functions)
Local/Central transfer (at unit + central level)
Local transfer (at unit of user level)
Central transfer (at central level)
3
2
1
X
5
=
Local/Central measurement
Local measurement (at unit of user level)
Central measurement (at central level)
3
2
1
X
4
=
Local/Central control
Local control (at unit of user level)
Central control (at central level)
3
2
1
MEASUREMENT
(Consumption)
CONTROL
(Use)
Weighting
Score
X 3 =
X
5
=
Total partitionability score:
+
Class
Class
Class
Class
Class
1,
2,
3,
4,
5,
PARTITIONABILITY
Class table and scores
not partitionable
hardly partitionable
fairly partitionable
partitionable
very good partitionable
22
31
40
49
58
-
30
39
48
57
66
Fig. 4. Criteria, weighting factors, scores and class table used in judging partitionability
Partitionability criteria, weighting factors and partitionability class
In figure 4 three possible ratings (3=positive, 2=neutral, 1=negative) are given for each
assessment aspect of partitionability. In addition, different weighting factors are introduced
for the assessment aspects (5=very important, 4=important, 3=fairly important, 2=hardly
important). The rating multiplied by the weighting factor gives the partitionability score. Thus
a final judgement can be given as to the overall partitionability. It is the weighted
partitionability score of the installation system concerned that comes within a certain score
range. This score can be expressed as a partitionability class and can be found in the relevant
table.
4.2 Judging adaptability
Figure 5 shows what is meant by the assessment criteria for the flexibility indicator called
adaptability. For this purpose three sub indicators of adaptability are used, disconnectibility
(installation components), accessibility (also components) and adjustability (measurement and
control).
ASSESSMENT OF ADAPTABILITY
Rating
Good (plug-in of installation components)
DISCONNECTIBLE Limited (disassemly is simple)
Poor (hard to take apart)
3
2
1
ACCESSIBLE
ADJUSTABLE
Weighting
Score
X 5 =
Good (components at infill level)
Limited (partly at infill, partly at support level)
Poor (components at support level)
3
2
1
X
4
=
Good (direct measurement/control)
Limited (only after major changes)
Poor (monofunctional, single use)
3
2
1
X
3
=
Total adaptability score:
+
Class
Class
Class
Class
Class
1,
2,
3,
4,
5,
ADAPTABILITY
Class table and scores
not adaptable
hardly adaptable
fairly adaptable
adaptable
very good adaptable
Fig. 5. Criteria, weighting factors, scores and class table used in judging adaptability
16
12
17
22
27
32
-
16
21
26
31
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Adaptability criteria, weighting factors and adaptability class
In figure 5 three possible ratings are given for each assessment aspect (3=positive, 2=neutral,
1=negative). In addition, different weighting factors are introduced for the assessment aspects
(5=very important, 4=important, 3=fairly important). Ratings multiplied by weighting factors
give the adaptability scores. Thus a final judgement can be given as to the overall adaptability.
It is the weighted adaptability score of the installation system concerned that comes within a
certain score range. The adaptability class can be found in the relevant table.
4.3 Judging extendibility
ASSESSMENT OF EXTENDIBILITY
Rating
CAPACITY
(Local supply
facilities)
Ample overcapacity 50 - 100%
Limited overcapacity 10 - 50%
No overcapacity 0 - 10%
3
2
1
Weighting
Score
X 5 =
CAPACITY
(Central supply
facilities)
Ample overcapacity 50 - 100%
Limited overcapacity 10 - 50%
No overcapacity 0 - 10%
3
2
1
X
4
=
DIMENSIONS
(Distribution
networks)
Ample oversized 50 - 100%
Limited oversized 10 - 50%
Not oversized 0 - 10%
3
2
1
X
2
=
LOCATION
(Shafts, duct
area)
Good (at unit ànd central level)
Fair (at local level)
Poor (at central level only)
3
2
1
X
3
=
Total extendibility score:
+
Class
Class
Class
Class
Class
1,
2,
3,
4,
5,
EXTENDIBILITY
Class table and scores
not extendible
hardly extendible
fairly extendible
extendible
very good extendible
22
31
40
49
58
-
30
39
48
57
66
Fig. 6. Criteria and weighting factors used in judging extendibility
Figure 6 shows what is meant by the assessment criteria for the flexibility indicator called
extendibility. For this purpose use is made of three sub aspects of extendibility, capacity (of
the supply facilities, both local and central), dimensions (distribution networks) and location
(ducting shafts and zones).
Extendibility criteria, weighting factors and extendibility class
In figure 6 three possible ratings are given for each assessment aspect of extendibility
(3=positive, 2=neutral, 1=negative). In addition, different weighting factors are introduced for
the assessment aspects (5=very important, 4=important, 3=fairly important, 2=hardly
important). The ratings multiplied by the weighting factors give the extendibility scores.
Thus, a final judgement can be given as to the overall extendibility. It is the weighted
extendibility score of the installation system concerned that comes within a certain score
range. The extendibility class can be found in the relevant table.
4.4 Judging multifunctionality
The last aspect used in assessing the flexibility of buildings is multifunctionality. A
multifunctional building or component can be used for several purposes. It permits a more
efficient utilization of the available space and enlarges the ductless area through clustering
and concentration. Another aspect that plays a role in the assessment of multifunctionality is
the extent to which a system is universal. Figure 7 shows the criteria to be used in this
context.
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Industrialised Construction
ASSESSMENT OF MULTIFUNCTIONALITY
Rating
INTEGRATION
(Installation
functions)
Integration > 5 functions
Integration 2 - 5 functions
No integration of functions (monfunctional)
3
2
1
UNIVERSAL
(Components)
Non-project-bound (> 75% of components)
Partly project-bound (25 - 75%)
Project-bound (> 75% of components)
3
2
1
Weighting
Score
X 5 =
X
4
=
Total multifunctionality score:
+
Class
Class
Class
Class
Class
1,
2,
3,
4,
5,
MULTIFUNCTIONALITY
Class table and scores
not multifunctional
hardly multifunctional
fairly multifunctional
multifunctional
very good multifunctional
9 - 12
13 - 16
17 - 20
21 - 24
25 - 27
Fig. 7. Criteria and weighting factors used in judging multifunctionality
Multifunctionality criteria, weighting factors and multifunctionality class
In figure 7 three possible ratings are given for each assessment aspect of multifunctionality
(3=positive, 2=neutral, 1=negative). In addition, different weighting factors are introduced for
the assessment aspects. The ratings multiplied by the weighting factors give the
multifunctionality scores. Thus, a final judgement can be given as to the overall
multifunctionality. It is the weighted multifunctionality score of the installation system
concerned that comes within a certain score range. The multifunctionality class can be found
in the relevant table.
4.5 Judgement of overall flexibility
In the foregoing we discussed in detail the criteria used in judging the four flexibility
indicators: partitionability, adaptability, extendibility and multifunctionality. Similarly, at a
higher level, the overall flexibility of an installation can be determined. Here, too, weighting
factors, scores and flexibility classes are used.
Weighting of the four flexibility key indicators and flexibility classes
Weighting factors indicate the degree of importance of the flexibility indicators relative to
each other. In order to arrive at a sound final judgement as to the flexibility of an installation
and for this reason also the building, each aspect has to be considered individually, but in
conjunction with other aspects. The flexibility of one aspect is less important than that of
another. That is why they have to be weighted with respect to each other. In determining
overall flexibility, the following weights were used: partitionability=5 (very important),
adaptability=4 (important), extendibility and multifunctionality=3 (fairly important). In
principle, users of this method are free to modify the weighting factors. It should be borne in
mind, however, that, if they do, the minimum and maximum scores to be attained in the
assessment of the overall flexibility of an installation will also be different.
By the same procedure as used in dealing with the individual flexibility aspects, the overall
flexibility class of the installation concerned can now be established. It is the weighted score
that comes within a certain range.
4.6 Flexibility assessment form
To record the outcome of the flexibility assessment of installation systems a special form has
been designed (see figure 8). It can be used both in judging existing buildings and their
installations and in formulating one's wishes with respect to new buildings to be erected. This
caters both the supply and the demand side of the building market. A default value for the
weighting factors have already been established, but may be adapted by the user. The rating
and the weight together produce the total flexibility score and class.
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
FLEXIBILITY ASSESSMENT
Installation system
Rating
Class
Default
Weighting
Score
Partitionability
X
5
=
Adaptability
X
4
=
Extendibility
X
3
=
Multifunctionality
X
3
=
Flexibility score:
+
FLEXIBILITY
Class table and scores
Flexibility Class:
FLEXIBILITY
Class table and scores
Class 1, not flexible
15 Class 2, hardly flexible 27 Class 3, fairly flexible
39 Class 4, flexible
52 Class 5, very flexible
64 -
26
38
51
63
75
Fig. 8. Layout of form for assessment of overall flexibility of installations
4.7 Different flexibility profiles
For a direct comparison between different installation systems and buildings use can be made
of the calculated flexibility classes. But this approach does not at once show which is the most
important aspect of flexibility. With one system emphasis may be on partitionability, whereas
with another it may be on the extendibility of the installation. To make this clear at a glance,
we can draw what is called a flexibility profile (figure 9).
Partitionability
Partitionability
5
Multifunctionality
Multifunctionality
3
1
2
1
5
Adaptability
3
Adaptability
4
Extendibility
Extendibility
Flexibility Profile System 1
Flexibility Profile System 2
Fig. 9. Two examples of flexibility profiles of installation systems
In the flexibility profile of installation system 1 (see figure 9) the partitionability score = 5,
the adaptability score = 3, the extendibility score = 3 and the multifunctionality score = 1.
Together they represent the total flexibility score (the shaded area). In this way different
installation systems can be easily compared by graphic means. In the case of system 1 the
predominant aspects of its flexibility are in the upper right-hand area of the profile, with
emphasis on partitionability and adaptability, whereas in the second profile the predominant
aspects are in the lower left-hand area, with emphasis on multifunctionality and extendibility.
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Industrialised Construction
5 Conclusions
With the so-called Flexibility Key Performance Indicators a detailed picture is obtained of the
flexibility demanded or offered. They can be used to judge the various flexibility aspects of
existing buildings and their installations, but also to formulate the requirements with respect
to flexibility when new buildings are to be realized. Thus, the Flexibility Key Performance
Indicators form a mean of communication on both the supply and the demand side of the
building market.
This paper describes four key indicators for measuring the flexibility of buildings:
partitionability, adaptability, extendibility and multifunctionality. In order to assess the
flexibility of buildings or their components, each key indicator is divided into a number of sub
aspects. For each sub aspect assessment criteria are formulated leading to three possible
ratings. Ratings multiplied by weighting factors give the different indicator scores. Thus, a
final judgement can be given as to the overall flexibility of a building. Here too, weighting
factors, scores and flexibility classes have been developed.
With this tool a detailed picture can be obtained of the flexibility demanded by the market
from the one hand and the flexibility offered by the buildings on the other hand. This enables
the parties involved in the realisation of a building to communicate about the flexibility of
that building and its installations in relation to each other.
When first applied in actual practice in the Netherlands, this method proved to be very useful.
Using the standardized assessment form, flexibility can be judged simply and rapidly.
Implementation of this technique in the field has produced a growing number of examples. At
the same time it has emphasized the fact that the assessment of flexibility depends very much
on personal or corporate views. Different clients judging the same installation will come to
different conclusions.
The technical installations are often found to be the key factor with respect to the possibilities
of adapting buildings. Installations in particular often prove not to be sufficiently flexible to
follow changes in their use without too many adaptations. Therefore Flexibility performance
indicators for installations could be regarded as a tool for assessing and discussing flexibility
of a building as a whole.
The described method has been based on the fact that installation systems in buildings form
more and more a vital component of buildings related to their future adaptability. Nowadays
50 -70% of the total initial costs of buildings consist of installation costs. Further
implementation in practice, evaluation and analysis are necessary. On the other hand the
research needs to be extended in the near future towards Flexibility Key Performance
Indicators of other building and construction components as well.
References
1. Geraedts R.P., Flexis; Dutch Building Research Foundation (SBR) and the Dutch
Institute for the Study and Stimulation of Research in the field of building installations
(ISSO), Rotterdam (1995)
2. Geraedts R.P., Vermaas H., Wees L.J. van: Verkavelbare Dragers en Kosten (Dutch:
Partitionable Buildings and Costs), Dutch Building Research Foundation (SBR 189),
Rotterdam (1989)
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3. Geraedts, R.P.: Costs and benefits of flexibility. In proceedings World Building Congress,
Wellington, New Zealand (2001)
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Industrialised Construction
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Under What Conditions are “Industrialization” and “Integration”
Useful Concepts in the Building Sector?
Stephen H. Kendall, PhD
Professor of Architecture
Ball State University
Muncie, Indiana, 47306, USA
[email protected]
Abstract
When are “Integration” and “Industrialization” operative concepts in the building sector? That is the question this paper
examines, primarily by discussing the multiple – and confusing - ways these terms have been used in the innovation and
building industry research literature. The paper proposes that reliance on fundamentally flawed definitions of these terms has
for too long obscured careful observation of how the building sector actually works and has thus made innovation and
advancement of the sector more difficult. It is proposed that the principles of Open Building have sorted out some of these
issues and thus serves as a useful innovation platform.
Keywords
Industrialization, Integration, Open Building, Levels, Distribution of Design
1
Introduction
"We teach students to integrate design and technology" (from a design course syllabus)
“A great epoch has begun.
There exists a new spirit.
Industry, overwhelming us like a flood which rolls on towards its destined end, has furnished
us with new tools adapted to this new epoch, animated by a new spirit.
Industry on the grand scale must occupy itself with building and establish the elements of the
house on a mass-production basis.
We must create the mass-production spirit.
The spirit of constructing mass-production houses.
The spirit of living in mass-production houses.
The spirit of conceiving mass-production houses.” [1]
1.1 Using Words
Words have their ambiguity, making them useful in everyday conversation because they
convey shades and nuances of meaning that, in the context of gestures, tone of voice and
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Industrialised Construction
social context, make communication possible. But when we need more formal descriptions,
these nuances and gestures are not at our disposal. In making formal descriptions, we must be
more precise and unambiguous, and are faced with the choice of coining new words or
narrowing the meaning of already known words. [2]
Either has it difficulties. The choice in this paper is to use two important and well-known
words – “industrialization” and “integration” - but to question their derivation, their
meaning and their capacity to obfuscate, thus making their continued use counterproductive.
The ambiguity of these words is well known. I will argue that this very ambiguity – and
the resultant confusion - has been a major barrier to better methods and better research in the
building sector. The words are used indiscriminately, as I will show. We have an
epistemological problem, in that the complexity of the processes by which parts are
aggregated in various stages into elements, components, parts, products, buildings and so on
remains ill-described. The paucity of unambiguous terms to amplify and clarify these
manifestations should tell us that the world of our concern – the ecology of people making
things - must largely have escaped intellectual and philosophical inquiry at least in the
English language - or at least not enough to bring the needed clarity and understanding.
1.2 Why is this subject important?
The building industry in every country is highly disaggregated. It is inextricably caught up in
local politics, real estate, labor markets and local geo-technical and climatic conditions, while
also being part of the global economy of finance and products and services. This “ecology” of
production is difficult to map and explain. [3] In part this is because data about the behavior
of this industry at other than a gross aggregate level is difficult and expensive to obtain, and
the data that is available is fraught with conflicting jurisdictions, collection and analysis
methods, and problems of industrial secrecy.
I use the term “disaggregated” to describe the “shape” of this industry - instead of
fragmented - for a reason. Disaggregated literally means "separated into component parts"
(from Webster’s). The sense in which I mean this is that the building industry – its many
agents and products, rules and processes – operates in ways fundamentally different from
other sectors in the economy, without an overall single "steering" mechanism other than the
"economy" or the “building culture”.
Most literature on the building industry has used the word “fragmented” to describe it,
referring to what is widely thought to be its disorganization. [4] [5] Fragmented makes sense
as a descriptor when the reference is to industries such as the automotive or aerospace
industries, in which very few players dominate and in which supply constellations are
organized in alignment with their relatively consolidated and top-down industry structure.
But unlike these industries, the building industry is characterized by the very large
number of parties who initiate building activities and regulate it, the equally large number of
parties who supply parts and services to these initiatives and the variety of outputs matching
the variety of those in control. And, unlike the automotive and aerospace industries, a very
large number of the players in building are laypeople operating in the “informal” sector, as
witnessed by the magnitude of sales at home project centers such as Home Depot and Lowes,
and their equivalents in other countries.
In this context, when the conventional wisdom is that the building industry should
behave in a way similar to the automotive or aerospace industries, it is little wonder that
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
words such as “industrialized construction” and “integrated” will be in currency. But those
industries are not suitable references, and therefore such concepts as “industrialized” and
“integrated” need to be used carefully when brought to bear to explain building industry
dynamics and to explain or characterize the building industry or innovative practices.
1.3 The romantic idea of integration has strong roots
Ortega writes, “The need to create sound syntheses and systemization of knowledge…will
call out a kind of scientific genius which hitherto has existed only as an aberration: the genius
for integration. Of necessity this means specialization, as all creative effort does, but this time
the [person] will be specializing in the construction of the whole.” [6]
This call from one of the 20th centuries major philosophers may capture best the drive for
that illusive wholeness that so many also in our field – the field of the built environment –
continue to express. It is the wellspring and the root of the idea of integration. This search
for “integration” has been widespread, especially in but not limited to the University. [7]
One of the more recent of such searches is by Christopher Alexander’s magnum opus,
titled The Nature of Order. [8] “This four-volume work is the culmination of theoretical
studies begun three decades ago and published in a series of books -- including The Timeless
Way of Building and A Pattern Language -- in which Christopher Alexander has advanced a
new theory of architecture and matter. He has tried to grasp the fundamental truths of
traditional ways of building & to understand especially what gives life and beauty and true
functionality to buildings and towns, in a context which sheds light on the character of order
in all phenomena.”
The span of time of Alexander’s work (C.A.1968-2008) corresponds closely to the
heightened interest, found in the academic and government sponsored building industry
literature, in the concepts of “industrialized construction” “prefabrication” and “integration”.
While Alexander would almost certainly reject many of the fundamental assumptions of those
advocating “industrialized construction”, there is arguably something shared nonetheless – a
sense of having lost the organic unity thought to have once obtained in the pre-industrial era.
This is certainly a powerful idea. But it is also romantic wishful thinking. I’d like to try to
explain why.
2 Industrialization is one thing, construction another
Let me begin with the word industrialization. [9] Industrialization has to do with mass
production of products of a general nature, parts that can be used by many people, acting
autonomously with their own purposes quite distinct from the purpose of the producer.
Examples abound, being an inevitable result of specialization, and pressures to reduce cost
and improve quality. In the inventory of parts from which buildings are assembled today,
most result from this process. There is good reason to think that this is not new, and
preceeds the industrial age. There has probably always been someone who, recognizing a
need, decided to make something that he expected someone else to want. From before
mechanization, this source of initiative has been part of the building culture. [10] Now we
harness machines and computers to help devise large catalogues of parts.
A cultural or business – rather than a “technical” - view of industrialization sees the
maker taking the initiative and assuming risk. After research and development, competitive
positioning, experimental prototypes, investment in capital equipment and infrastructure,
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Industrialised Construction
finding a place in a supply constellation, the producer decides if the risk will eventually earn a
profit. The result is the production of small and neutral parts suited to a range of users. These
parts are “project independent”. Users, attracted to these products because of their utility to
their individual purposes, decide to use them instead of making them (the buy vs. make
decision).
Industrially produced, project independent parts are generally neutral enough that they
can be tested and certified by nationally and internationally recognized testing bodies such as
the UL (Underwriters Laboratory), making local testing and approval unnecessary. Today,
building parts are produced in sophisticated factories, using well-organized production
processes. In this process molds, jigs, automated equipment, labor, and supply chains are in
place using product templates, catalogues or libraries of parts (now stored as parametric
elements), and so on. That is, the product is “designed” even if parametrically, but production
is undertaken at the risk of the producer.
Construction, on the other hand, is the production of an artifact never seen before and
never to be exactly repeated. In construction, the user takes initiative, assumes the risk and
reaps whatever profits result.
The image of a great basket of parts helps. The basket is filled with parts produced at the
risk of the producer without knowing their downstream application (industrial production).
The construction process involves reaching into the basket of available parts and selecting
those needed for the artifact to be made, of whatever scale or complexity. The locus of
initiative is, again, the distinction. [11]
Prefabrication (I believe this is what is meant by “bespoke” production in the UK) is a
variation on construction, similar in that the user takes initiative (places an order) and assumes
risk (having provided the design). But unlike construction, prefabrication takes place at a
distance from the site where the part made will be used. It can employ sophisticated means,
labor saving methods, and information management. The result is project-dependent and is
therefore constrained by the same factors as construction. [12]
This by no means exhausts the discussion, because the staged process of manipulating
parts to make more complex forms occurs in complex stages involving overlapping domains
of control and influence. [3]
2.1 No Conflict between Industrialization and Construction
There is, of course, no conflict between the most advanced industrialization and construction,
or between industrialization and vernacular ways of building. [13] The famous “2x4 system” used to build houses in the US - is a case in point. This vernacular is fed by a vast industry
making the parts – all produced in highly automated plants – and all highly “industrialized”.
But no one would say that this way of building constitutes “industrialized construction”. [14]
While there is no conflict between these two processes, conflating industrialized methods
of production and construction (or prefabrication) causes confusion. As noted above, the
difference does not have to do with the use of sophisticated equipment. Robots can be found
on the construction site and in factories. Hand labor is found in both. Prefabrication of roof
trusses can be done by hand, or in highly automated plants, driven by sophisticated CAM
software, using products of industrialization but producing parts (trusses) ordered by their
user – in which case, the trusses are not examples of “industrialized construction” but of
“prefabrication”.
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These are essentially business views, and usefully distinguish the matter of initiative, risk and
control. While distinct operations and behaviors, they need each other today more than ever.
Both complement the other. But they are different by definition and in practice.
Why the term “industrialized construction” has emerged at all is interesting. It is the
same thinking that has fostered the emergence of the term “mass customization”, an idea in
currency that also conflates terms and processes unnecessarily. [15]
A reading in the literature suggests that this confusion is largely an academic problem
and that in practices that survive, the two loci of initiative sort themselves out. The efforts of
even the most brilliant architects confusing these issues have fallen pray to ideologies that
separate them from this reality. [16] Therefore the issue at hand is that the academic and
research communities are out of step with the real world and are thus not able to be as helpful
as they could be if theory matched what is really happening.
3 Integration
Children in Waldorf schools around the world learn at an early age to experience the merging
of two primary colors into a third one. They use the wet paper method. Each child is given a
sheet of wet watercolor paper, a brush and two primary colors. The children are invited to
apply one color directly to the wet paper, then the other color. Right in front of the child’s
eyes, the two colors merge and form a third color. On the paper emerges the reality of three
colors: the two original primary colors and the result of their merging. This may be one of
the child’s first ways to grasp the idea of two things loosing their identity to a third reality.
This seems to be an example of integration.
As mentioned above in the discussion of “industrialized construction” in the building
industry literature, reference is always made to other “more mature” or “more integrated”
industries, such as the automotive industry. Much effort is spent comparing the building
industry to these, because they are seen as “integrated” and not fragmented. Fragmented is
bad; integrated is good.
In the Oxford Dictionary, “integration” has several meanings, but the most common one
is the idea that many things become one. The word has taken on special significance in
discussions of racial relations. Its use suggests the possible loss of identity of the parts to the
whole. In a very practical sense of course, this is not useful either in designing, constructing
or later managing and repairing buildings.
3.1 Design Integration
What can this phrase mean? What are its origins? In what context is this term found? These
are questions worth exploring, because the phrase is so much in currency, and has been for so
long. We might begin by unbundling the phrase “design integration”. First, what does
designing mean?
If by designing we generally mean what we do when we make a proposal for what
should be built, by someone else, for someone else to use, we probably also have in mind
some ideas regarding who is involved in these tasks – who takes initiative, who controls what,
and so on.
Fundamentally, we distinguish or partition the act of designing from the act of making
what is proposed. Of course, once the distinction is made, designing and making can be
27
Industrialised Construction
undertaken by one party, or by several parties. This is not new. Specialization brought us this
distinction very early, always ruled by convention and tacit knowledge as well as specialized
skills and tools. I have participated in both, having practiced as an architect making drawings
to instruct a builder what to do, and I have also built by my own hands what I have designed.
If that is at least a point of departure for “designing”, what is integration when the word
is attached to designing? In architectural and engineering discourse, we see the use of the
phrase “design integration” or “integration of design and production”. Experts in the building
industry around the world have worked diligently for more than 50 years to put the concept of
“design integration” into practice. It seems that the latest effort to accomplish “integration”
will be found in building information modeling (BIM).
I believe that it is important to be very careful in using the word integration. It has little
to offer in the way of descriptive power, information or insights for the building industry
except in specific ways that I outline below.
Here is a case in point that demonstrates how the word has reached a state of such
ambiguity as to render it virtually useless. At a recent international conference on Design
Management (CIB W96) in Copenhagen, a session was organized called Design Integration.
[17] I was asked to be chair of that session, which allowed me to read all of the papers. This
reading revealed the following words or phrases associated with design integration:
• Concurrent engineering
• Multidisciplinary teams
• Introducing knowledge early
• Thinking in levels of abstraction
• Optimizing
• Collaborative participation
• Inclusion
• Sharing of knowledge and learning,
• Sharing of visions
• Group processes
• Interoperability
• The idea that problems can be subdivided into overlapping, interconnected segments that
correspond to existing or emerging disciplines but are connected in a coherent and
comprehensive manner
• Lean construction
• Supply chain integration
• Value engineering
These were the actual terms associated with “design integration”, found in the dozen or more
papers I read. What are we to understand from this? Does design integration mean joining
designers together somehow? If so, exactly how is this to be done? Is the joining done at the
hip, or by brain links? Do we find partnerships, contracts, virtual networks, or the law as the
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
operational devices of design integration? Does design integration mean a hierarchical
relationship between parties, or a relationship of equals, or neither?
Experts in the building industry around the world have worked diligently for more than
50 years, to operationalize the concept of “design integration”. The term of reference has been
found in the innovation literature for at least that long. What does the use of this term suggest
in terms of implicit assumptions? What has been learned in the past 50 years of efforts to put
this concept into practice? We need more academic studies that examine this.
I would suggest that a resolution can be found by introducing the concept of control, one
of the central concepts in Open Building. That is, we need to know what party (an individual
or group) makes executive decisions. This, to make the phrase “design integration” useful, we
must ask “Who controls what?” This is a decidedly political question that takes us outside our
professional or “technical” expertise into a field of social and cultural discourse and values.
4
Effective Terms of Reference
As mentioned above, I would suggest use of the term “disaggregated” instead of
“fragmented” when describing the realm of agents involved in designing and building. This
means that a number of independent parties are working on a project - consultants from all
kinds of design disciplines, even geographically distributed. The relations between these
parties – their patterns of control - is key. There is really no question that projects of any size
today need many disciplines and thus many parties to get the work done.
What are the relations between these parties? There are many patterns of relations, of
course; we have teams, partnerships, collaborative structures, virtual corporations, vertically
or horizontally organized networks. The point is, we would find it very strange and probably
just simply bad if one party (an individual or a company) claimed to be able to control
everything! For a long time we have had specialization and it won’t go away. Rather, we
experience more specialization as the world becomes more complex and fast paced. It would
be a terrible idea if the building industry would model integration in that sense.
Do we really want three companies controlling all the building activities, with tight, topdown supply chains and so on, in the US, or in the UK? I think few would argue in favor of
that, or in favor of abandoning the range of small, medium and large organizations that give
the building industry tremendous agility, dynamism and resilience and innovative capacity.
Clearly, “integration” or “integrated design” is a model for building technology or
building processes in particular situations, and is not a general model. How after all do we
repair a unity (an integrated system) when it needs to be repaired or modified except by
destroying or discarding it? A more practical approach – and a more sustainable one - is to
identify the parts making the whole and disentangle them from their neighbors with minimal
conflict and perturbations into the entire assembly, another important principle of Open
Building.
Knowing how to do this in increasingly complex assemblies is not going to advance as
long as the term integration shrouds the real issue: In complex assemblies like buildings, no
single party controls the whole, either during its design, its construction or its use. Further, we
can be assured that in the future, control of parts will remain highly distributed.
The term integration is not useful in architectural discourse as used today, either, beyond
casual conversation or in the rhetoric of the critic. It has come to mean so many things that it
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means nothing. No one is able to point to several drawings and declare with assurance that
"this project is integrated and that is not".
The reason for making this point is the following. When we make a complex artifact like
a building, we compose it from many parts. During the process of composing, we need to
change parts, delete some, adjust them, or add new ones, as we learn more or as conditions
outside our control change. It is normal that when we change one part, others are implicated.
Soon the perturbations in the whole can become too complex to be controlled successfully
when every part is subject to alteration upon the change of a given part, and when control of
parts is distributed among a number of parties. So, to manage the complexity, we decide to fix
some configurations - leaving them stable - which become constraints on the manipulation of
other configurations or parts. We follow this process until we are think we are "done" with the
designing or until the party requesting it gives approval.
Since, in designing a building (or even a part of a building such as a curtain wall), we
cannot possibly handle the reverberations resulting from all parts being equally dependant on
all other parts, we "freeze" or "fix" certain configurations as noted above, so we can actually
handle the complexity of the task. This results in a hierarchy of configurations making the
whole, a hierarchy of our own making in some cases, a hierarchy of dependencies dictated by
natural forces (gravity, resource flows, etc) and some strongly directed by social conventions
(territory, etc) and some by cultural norms (style, systems, codes, etc).
What I want to say is that the lure of "integration" has for many decades allowed us to
avoid the hard work of understanding the actual operation of complex forms under conditions
of distributed control because we have sought to model our industry on industries that by their
nature have become equivalent to monopolies or come close to it.
4.1 Control
Integration has a "PC" (politically correct) ring to it - "Lets make things UNIFIED…", etc.
This is so pervasive that we have avoided a recognition of what really matters: that complex
wholes composed of many parts have unavoidable, complex and difficult to map dependency
relations, only some of which are subject to choice, and all of which are subject to control.
Maybe "integrationists" want to eliminate dependencies by unifying parts, so that the
parts no longer have identities among which dependencies can occur! Along with this
naturally goes a unification of control. Clearly, if we have a whole composed of two parts, the
individual parts can be controlled by one party, or by two. The more parts we have, the more
potential parties can take part in making and changing the artifact. When all parts are made
into one (integrated - unified) clearly only one party can exercise control because the whole
cannot be sensibly partitioned. The "one party" may be a group "acting as a whole" (by
consensus or by vote) or it can be one individual who seeks out the advice of others but who
has exclusive authority to act (control). We know the difference, however, which only goes to
raise the question of how groups actually "work together" in making form.
4.2 Levels of Intervention
One way out of the trap of “integration” is to understand the idea of levels of intervention, a
third important part of Open Building theory. [18] This is not a new idea, but is easily
forgotten, and in any case constitutes an inevitable trend.
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Why has this trend emerged? The answer lies in a convergence of three dominant
characteristics of the contemporary urban environment. First is the increasing size of
buildings, sometimes serving thousands of people. Second is the dynamics of the workplace
and the marketplace where use is increasingly varied and changing. Third is the availability
of, and demand for, an increasing array of equipment and facilities serving the inhabitant user.
In that convergence, large-scale real estate interventions make simultaneous design of the
base building and the user level impractical. Social trends towards individualization of use
make functional specification increasingly personalized. Greater complexity and variety of
the workplace demand adaptation by way of architectural components with shorter use-life,
such as partitioning, ceilings, bathroom and kitchen facilities, etc.
The observed separation of base building from fit-out includes utility systems as well.
Adaptable piping and wiring systems on the fit-out level, for example, connect to their
counterpart and more fixed main lines in the base building, which themselves connect to the
higher level infrastructure operating in the city.
Thus we see a significant contrast between what is to be done on the user level on the one
hand and what is understood to be part of the traditional long-term investment and
functionality of the building on the other. This is the reason for the emergence of the base
building as a new kind of infrastructure. [19]
The distinction here - between “levels of intervention” - is always useful when we
compare infrastructure with what it is serving. In the case of buildings, the comparison has
multiple dimensions, including the following, framed in terms of familiar in the US office
building sector if not more broadly:
BASE BUILDING
INFILL or FIT-OUT
Longer-term use
Shorter-term use
Public or common service related design
User related design
Heavy construction
Lightweight components
Long-term investment
Short-term investment
Equivalent to real estate
Equivalent to durable consumer goods
Long term mortgage financing
Short term financing,
When this distinction is made in practice, it is usually the case that each level is under the
control of a different “party” or agent. It is even then possible to say that each such “party”
must “integrate” their work to maintain quality, schedule and cost. But the use of
“integration” here is directly aligned with a pattern of control, rather than being a technical
definition. That is the key point: integration has to do with the exercise of control.
5
Conclusions
The implications of the perspective I've offered can be surmised. Many aspects of our work as
architects and engineers and builders – in practice, research units and teaching - are involved.
Adopting the perspective I advance would be very disruptive. I would venture to say,
however, that if we don't adopt it we should anticipate a continued lack of effectiveness in
dealing with the questions that will not go away. That is not to say that students will not
continue to flock into the schools, or that creative and skillful architects and engineers will not
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Industrialised Construction
continue to practice and practice successfully. But in a larger sense, I believe that our future
depends on coming out from behind the shroud of such terms as integration and industrialized
construction and all that is embodied in the terms.
The problems in pursuing this are not trivial. Necessary professional re-orientation may
well determine the pace, direction and quality of change. Note that the practical examples of
working with levels of intervention cited above have emerged from sound economic
reasoning and a willingness to respond to market forces, not from ideology.
The time may have come to establish a more explicit platform for study and development
of what seems to have come not as a new design idea, but as a new reality to be taken
seriously.
References
1. Le Corbusier. Towards a New Architecture. Mass-production Houses, p. 225 (Here quoted
from the translation of the thirteenth French edition with an introduction by Frederick
Etchells). From: Essential Le Corbusier L’Esprit Nouveau Articles, by Le Corbusier
Architectural Press, Oxford (1998)
2. Rosenthal, Peggy. Words and Values: Some Leading Words and Where They Lead Us,
New York; Oxford: Oxford University Press (1984)
3. Kendall, Stephen. Control of Parts: Parts Production in the Building Industry. Unpublished
PhD Dissertation, MIT, Cambridge, MA, 1990.
4. Bender, Richard. A Crack in the Rear View Mirror: a view of industrialized building. New
York, Van Nostrand Reinhold (1973)
5. State of the Art of Industrialized Building, prepared for the National Commission on Urban
Problems (1968)
6. José Ortega y Gasset, Mission of the University. Edited and translated by Howard Lee
Nostrand. Transaction Publishers, New Brunswick, NJ (1992)
7. R. Roy, “The Interdisciplinary Imperative: Interactive Research and Education, Still an
Elusive Goal in Academia,” Roy (ed), Writers Club Press, iUniverse.com, Inc, Lincoln, NE
(2000)
8. Alexander, Christopher, The Nature of Order. Oxford University Press (2002 – 2005)
9. Willem van Vliet (ed). The Encyclopedia of Housing. Sage Publications, London (1998):
“Industrialization” pp 315-316.
10. Davis, Howard. Building Culture. Oxford University Press (1999)
11. Willem van Vliet (ed). The Encyclopedia of Housing. Sage Publications, London (1998):
“Construction Technology” pp 83-85.
12. op cit. “Prefabrication” pp 425-426.
13. Habraken, John. The Structure of the Ordinary, MIT Press (1998)
14. Kendall, Stephen. "The Entangled American House", Blueprints, The National Building
Museum, January (1994) pp 2-7
15. C.C.A.M. van den Thillart. Customized Industrialization in the Residential Sector: Mass
Customization Modeling as a Tool for Benchmarking, Variation and Selection. Sun
Publishers, Amsterdam (2004)
16. Herbert, Gilbert. The Dream of the Factory Made House. MIT Press (1984)
17. Emmett, Stephen and Prins, Matt (ed). CIB W096 Architectural Management.
Proceedings: Designing Value: New Directions In Architectural Management. Technical
University Of Denmark, Lyngby, Denmark (2005)
18. Habraken, op cit.
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19. Habraken, John and Kendall, Stephen. “Base Building: A New (Private) Infrastructure”
(unpublished manuscript), October 2007.
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Adaptable Futures: Setting the Agenda
Katy Beadle, Alistair Gibb, Simon Austin, Almudena Fuster and Peter Madden
Department of Civil and Building Engineering, Loughborough University, Loughborough,
Leicestershire, LE11 3TU, United Kingdom
{K.Beadle, A.G.Gibb, S.A.Austin, A.Fuster, P.Madden}@lboro.ac.uk
Abstract.
Currently the majority of buildings are designed and constructed as bespoke creations to suit a particular use at a certain time,
with little thought for the future. The Adaptable Futures project, introduced in this paper, aims to facilitate the development
of adaptable buildings in the UK that take account of an often uncertain future. This paper gives a brief overview of the
project and then goes on to describe the two industrial case studies being used as the main sources of data collection for the
project. These are a pre-configured concept, Newways, developed by Pharmaceutical organization, GSK, and a reconfigurable concept, Multispace, created by architects 3DReid. Findings from a recent workshop looking at adaptable
buildings are then presented.
Keywords
adaptability, pre-configuration, re-configuration
1
Introduction
This paper provides a summary of the Adaptable Futures research project being undertaken at
Loughborough University. An introduction to the project is presented that includes an
overview of the research, the key objectives, a brief description of the context, methodology
used and the industrial case studies that form the focus for the project. The initial findings
from a workshop 4 with industry partners are then presented and next steps for the project
identified. The paper builds on previous publications presented by the research team on the
same topic, including Towards Adaptable Futures [1] presented at ManuBuild 1st
International Conference and The Multispace Adaptable Building Concept and its Extension
into Mass Customisation [2] presented at Adaptables ’06.
1.1
Overview of the Project
The Adaptable Futures project is a three year multi-disciplinary research project that aims to
facilitate the development of adaptable buildings in the UK through academic research and
examples from industry. The project involves academics and researchers from the following
sectors: construction, architecture, quantity surveying, business, project management and
engineering.
The adaptability of buildings is being investigated under two design strategies, preconfiguration, dealing with initial design choices and re-configuration, looking at subsequent
changes in use. These design strategies and their definitions are being developed as part of
the research and a typology for adaptable buildings will be created to enable their comparison
and assessment.
4 The authors acknowledge the input to the workshop from other members of the Loughborough research team,
namely: Andrew Dainty; Christine Pasquire; Jim Saker; Vicky Story and Cephas Idan.
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1.2
Context
Currently, the majority of buildings are designed and constructed as bespoke creations to suit
a particular use at a certain time, with little thought for the future [3]. The 21st century has
brought with it economic and environmental drivers that have and will challenge normal
practice as well as starting an era of unprecedented change in UK construction [4]. These
changes include: faster design and production to reduce client uncertainty and cost; much
wider adoption of lean manufacturing approaches (including offsite); and increasing demand
for infrastructure reconfigurable to future needs that are usually unpredictable [3]. In a
survey of high profile UK property developers and agents [5], 94% saw the need for an
adaptable building solution providing associated capital cost increases were minimised.
Environmental benefits of adaptable office buildings have been estimated by Larsson [6] as a
15% reduction in (a) air emissions and (b) demolition solid waste. According to DEFRA
[7], 24% (70Mt pa) of all waste is construction demolition materials and soil. There is
clearly both a business and sustainability case for extending the useable life of our building
infrastructure. The real challenge is how to make buildings adaptable without creating
unnecessary redundancy and increases in first cost.
There have been few recent attempts to incorporate adaptability into new buildings and those
that exist have been almost entirely residential. The move to adaptable buildings requires an
industry step-change in the way in which structures are conceived, designed and assembled
[3]. The main geographic focus of recent flexible building design research has been Japan
and The Netherlands [8]. Japan has lead the way in developing mass-produced housing from
a purely cost driven commodity item towards a customisable, high quality product which
delivers a significant degree of flexibility to the end client [9]. Habraken promoted the
concept of open building in the 1960s. However, the practical application of open building
has been limited to one-off projects utilising a variety of systems, mainly in housing [10].
The theoretical concepts behind open building have been researched but few projects have
been built using this principle and those that have been completed have not used the inherent
flexibility as intentioned [11].
1.3
Objectives
The objectives of the research are to:
1.4
•
identify future scenarios and design criteria for adaptable buildings to respond to
•
understand the success or failure of past attempts, both technological and human
•
create novel product architecture models and associated methods of analysis to
optimise the configuration of components and systems against customer needs
•
invent cost-effective building systems and technologies best suited to provide the
required levels of adaptability over their life cycle
Methodology
The main sources of data collection for the research are two case-study solutions from
industry that fit under the two design strategies. These are a pre-configured example,
Newways, developed by GlaxoSmithKline (GSK) and Bryden Wood McLeod (BWM) and a
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
re-configured example, Multispace, developed by 3DReid and Buro Happold 5. Newways is
a pre-configured component building system designed to suit the needs of GSK to create any
one of three building types that GSK require. Multispace is a re-configurable concept that is
a customisable multi-use building design that can be built as or changed into offices,
residential apartments, hotel or retail. These case studies are explained in more detail below.
A number of other organisations that make up the reference group are also contributing to the
research. A mixed-method approach is being used to collect data from these sources. This
approach includes: action research with the industrial case studies; interviews; focus groups;
workshops with the research collaborators; scenario modelling; and dependency structure
matrix analysis.
2
Newways
The main aim of Newways is to reduce design and build time for GSK’s facilities from 24
months to 13 weeks to enable the drugs that they produce to get to market earlier [12] or to
enable the delay of the design and construction of buildings until the drug is approved, thus
reducing risk of producing sub-optimal buildings and facilities. To achieve this GSK are
working with BWM to develop a pre-configured kit of parts used to build three building
types: research laboratories; primary production; and secondary production facilities. The kit
of parts is shown in Fig.1 and consists of 900 parts, 90 components, 30 assemblies that make
up the three building types or assets [1]. GSK see the benefits of the Newways concept as:
reduced risk; reduced supply disruption; reduced capital project contingency (10%); reduced
cost due to bespoke design; and improved technology transfer [13]. The strategy used to
develop the buildings is the 10:80:10 (context: products: enhancement) rule, which means that
the majority of the building is standard components, but the site-related elements and the
finishes are customised [1].
Fig. 1. Newways kit of parts (GSK)
5 The authors acknowledge the significant contribution of the Adaptable Futures project partners: Nigel Barnes
& Al O’Dornan (GSK); Frank McLeod & Martin Wood (BWM); Paul Warner & Chris Gregory (3DReid);
Adrian Robinson & Mick Green (Buro Happold).
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Industrialised Construction
2.1
FlexiLab
The Newways concept is being driven by the use of FlexiLab that creates flexible open plan
laboratory spaces that can be re-configured when necessary [14]. The FlexiLab system
consists of modular mobile laboratory furniture on wheels that has been designed to adapt to
new laboratory requirements [13]. The services for the laboratory come through sockets in
the ceiling that the equipment plugs into. The laboratories can be fitted out very quickly and
can be easily reconfigured by the scientists using them. The life-cycle cost was calculated as
being lower as although the capital cost is more, the reconfiguration cost is negligible [15].
2.2
Services
At present GSK have standard M&E components for their production facilities, with facilities
being designed around these services as they are replicated. The manufacture of the
components happens at the same time as the construction of the building and they are brought
onto site on the back of a lorry and bolted onto the structure [15]. The Newways concept is
to have service ducts around the outside of the building that will contain these M&E
components and other services [14].
2.3
Components
At present the parts that make up the Newways components are being developed and
rationalised. The fit-out and module elements are in the feasibility stage, cladding and plant
are in the concept stage and the structure has gone through scheme design and is now in
detailed design. Currently the number of column parts are being rationalised to reduce the
number of column types. The floor cassette is the most developed component, with a
prototype having been created and tests completed. The floor cassette has been designed to
be installed quickly and consists of a pre-cast concrete slab with connections so it can be
slotted into place. The grid size currently used came from GSK and the best grid was seen
as 12m x 12m as this is the set up of the FlexiLabs. 12m x 4m was chosen for a floor
cassette to create these grids, as they can be moved easily on lorries and provide a loose-fit,
which is seen as being more flexible. The grids can also be configured with 4x6, 4x8 and
4x10 components. A 0.3% premium will be paid to make sure that all floor cassettes can be
used anywhere; it was suggested that this must result in savings overall. The aim is to create
a catalogue of Newways components that would include all the parts and how they could go
together to form various components and assemblies [14].
2.4
Industrial Processes
To cater for the products that GSK produce a shorter construction time is needed to enable the
construction of facilities to be started later to reduce risk and waste and increase efficiency.
To do this a continuous process is suggested by GSK that will incorporate: programme
management; product development; supply chain management; production of components
and assemblies; and production systems. A number of projects would then be produced
from this and the process would be able to constantly improve. The process would need to
operate in other countries as products moved there for production, this would require control
of the supply chain. GSK would need to build up and reconfigure the supply chain as
necessary, identifying what currently exists and how to fill any gaps that appear [16]. This
could involve building relationships directly with manufacturers rather than suppliers [14].
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2.5
Cultural Change
To enable Newways to be successful, cultural change is necessary. The relationship with
subcontractors was seen as the most important aspect of cultural change as these were seen as
difficult to control, therefore relationships with suppliers need to be developed. To work
with suppliers directly, a base load of work needs to be guaranteed to provide consistency and
comfort to strengthen the supply chain. The way in which the connections between
parts/components/assemblies are made is very important, this process needs to be controlled,
to do so it could be moved off site, which could also increase efficiency. Business and the
supply chain need to be reformed to see cultural change. A new way of working is needed,
to do that an understanding of the business is important as there is a need to make a market for
the product. Simple cultural changes like getting parts, components and assemblies
delivered on time and when they are needed on site are crucial to shorten the construction
period for buildings [16].
3
Multispace
3DReid, formerly Reid Architecture, conducted a concept study of re-configurable adaptable
buildings. The concept developed from this is called Multispace and presents an adaptable,
multi-use design that could be the basis of a variety of offices, residential apartments, hotels
and retails developments [17]. Mixed-use developments are increasing in popularity and
Multispace offers the opportunity for these buildings to respond to market conditions by
changing use without significant adjustments to the external envelope. This could maximise
commercial return and reduce risks to landlords [2] as well as reducing waste. The aim of
the study was to offer some potential solutions to the problems faced by creating multi-use
buildings, these were addressed by identifying a set of design parameters [17].
3.1
Design Parameters
The technical requirements of a set of building design parameters was compared for each
building use selected. This enabled acceptable values for each parameter to be proposed to
develop a generic specification for an adaptable building [2]. The design parameters were
selected to allow a change of use without requiring a significant change in the building
envelope. The design parameters included: storey height; building proximately, form and
plot density; plan depth; structural design; vertical circulation, servicing and core design; fire
safety design; and cladding design [17].
3.2
Requirements
A summary of the proposed specification requirements for an adaptable building from the
Multispace concept are shown in Fig. 2. Fig. 3 shows a visual representation of what a
building developed using the Multispace concept might look like.
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Industrialised Construction
Fig. 2. Requirements for adaptable buildings [17]
Fig. 3. Visualisation of the Multispace concept [17]
4
Workshop Findings
In this section results from a workshop [15] with the industrial collaborators and the reference
group are presented. The workshop focused on the two design strategies addressed by the
research; pre-configuration and re-configuration. During the workshop participants were
asked to document their experience of adaptable buildings that could be categorised under
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
these design strategies. They were then asked to discuss, in small groups, the pros and cons
of these examples and the opportunities and challenges for delivering the two types of
adaptable buildings identified. In this paper five themes, out of the ten identified during the
workshop, are discussed. These include: components, systems, industrial process, flexibility
and society.
Data were collected from workshop participants using audio and video recording. The
discussion elements of the workshop were treated like focus groups, with specific questions
being asked and discussed by each group. Each group was made up of 4-5 industrial
collaborators, members of the reference group and members of Loughborough University.
Participants were split up according to their backgrounds, which included: industry bodies;
producer/contractor; academic/researcher; designer/consultant; and client/developer, this
enabled a mix in each group. Each group had a facilitator to guide the discussion and a note
taker to allow the facilitator to feedback after the session.
4.1
Components
During the workshop many examples of standardised components used in various systems
and buildings were identified. The use of standard components was seen positively as the
specification is known. It was felt that components needed to be fit for purpose and so good
that people would want to use them. A library of components was suggested as at present
they are not used universally. Connections between pre-configured components were seen
as the most important part of the design by many of the workshop participants. There was
some debate surrounding trying to make as many of the buildings’ parts as possible like
furniture or ‘stuff’, as this would enable re-configuration to take place more easily, an
example of this is the GSK fume cupboard. It was felt, however, that this approach was
constrained by current thinking.
4.2
Systems
Panelised, volumetric, steel frame and modular systems were discussed during the workshop
as well as the idea that these can be ‘mixed and matched’. It was felt that the systems, rather
than the buildings themselves were key to some examples presented, which represented a
different approach to design. Due to this, architectural quality was a concern for some
systems, but it was stated that bespoke buildings could be created either permanently or
temporary as the limitations to the designs were said to be reducing with more experience of
the various systems.
4.3
Industry Processes
The supply chain involved in the development of pre-configured buildings was discussed at
length by the workshop participants. It was felt that the most benefit comes when a supply
chain is in place to deliver the standard components required. The issue of who should pay
for pre-manufacture and storage of these components was discussed as this was sometimes an
obstacle to pre-configured buildings. The supply chain was described by participants as being
an open or closed system, with an open system enabling components to be sourced from
various manufactures, whilst a closed system relies on a particular set of components from
specific manufacturers. The scale of the project for which components are required affects
this, as if a large volume of components are necessary then benefits can be seen by having a
separate supply chain. Another aspect of pre-configured buildings is that much of the work
is done offsite, which was highlighted as being faster, less wasteful and more efficient.
41
Industrialised Construction
4.4
Flexibility
Occupants were thought to need the opportunity to remove or add space, it was suggested that
this should be dealt with in the early stages of the design process. Many examples of
internal flexibility were presented during the workshop. Hospitals were identified as
needing internal flexibility as it was stated that radical change occurred every five years.
Several multi-use buildings were discussed which ranged from a 1960s banqueting hall to a
science park designed for a very large spectrum of potential uses. There were, however,
worries that the optimum solution would not be achieved by these examples and that
compromises would always need to be made. Examples of building that were designed to be
dismantled and relocated were presented and some had been re-configured as designed, but
many others had not and it was envisaged never would be. There were also many examples
of buildings that had been designed to be extended and some had been, but many had not been
extended in the way they were designed to be.
4.5
Aesthetics
It was outlined that the aesthetics of pre-configured buildings could be bespoke as many could
be ‘dressed’ as necessary. Aesthetics were given as a reason why some buildings were not
re-configured as designed, as fashions change. Workshop delegates argued that the
aesthetics of some pre-configured buildings had not been very inspiring, but if time and
thought was invested it was felt they could be as varied as conventional buildings. It was
felt by some participants that the perception of pre-configured buildings was fairly negative,
but that this was improving as designers became more involved in the process. ‘Secondhand’ buildings were also seen to have a negative perception. It was believed that a change
in mindset was needed for multi-use buildings and that these should be strived for to help the
sustainability agenda. Choice in pre-configured buildings was important to enable
developers to put their own mark on buildings and to respond to the local context. It was
also felt that there was a massive motivating force for humans to control their environment
and have that choice.
4.6
Summary
To summarise, the findings from the workshop for adaptable pre-configurable and reconfigurable buildings raised the following elements as being important:
•
Components must be designed to be fit for purpose
•
A library of components should be created to enable universal use
•
Connections are a vital part of the design of pre-configured buildings/systems
•
Building parts, especially those internally, should be detachable
•
Thinking of pre-configured systems rather than buildings will lead to a different
design approach
•
Architectural quality can be achieved with time and thought
•
The supply chain is key to the delivery of components
•
Storage of components needs to be addressed
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
•
The supply chain can either be open or closed; depending on the volume of
components
•
Re-configuration requirements need to be addressed early in the design process
•
Solutions created for multi-use buildings may not be optimum
•
Many re-configurable buildings are not re-configured as intended
•
A change is mindset is needed for adaptable buildings to be successful
•
Client or developer choice of building design and aesthetics is necessary
5
Conclusions
This paper has introduced Loughborough University’s Adaptable Futures project and has
presented the two main sources of data collection, the Newways pre-configurable concept
being developed by GSK and BWM and the Multispace re-configurable concept created by
3DReid. The paper has also covered issues that are of concern to each of the case studies
and provided some findings from a workshop conducted with the industrial collaborators and
the reference group for the research.
The next steps in this research are to investigate the two case studies in more depth and
conduct action research to enable novel product architecture models to be created as well as to
invent cost-effective building systems and technologies. Other case studies will also be
examined to aid this process and to identify parameters, materials and technology for
successful adaptability. It is intended that aspects of this further work will be presented at
the I3CON conference.
References
1. Gibb, A., Austin, S., Dainty, A., Davidson, N., Pasquire, C.: Towards Adaptable Buildings:
pre-configuration and re-configuration – two case studies. ManuBuild 1st International
Conference, The Transformation of the Industry: Open Building Manufacturing.
Manubuild, The Hague (2007)
2. Davison, N., Gibb, A.G., Austin, S.A., Goodier, C.I., Warner, P.: The Multispace
Adaptable Building Concept and its Extension into Mass Customisation. Adaptables ’06,
International Conference on Adaptable Building Structures, Vol.3, 12-7. Eindhoven
University of Technology, Eindhoven (2006)
3. Gibb, A., Austin, S., Dainty, A., Saker, J., Pasquire, C., Story, V., Goodier, C.: An
Integrated Project Proposals to the IMCRC (Innovative Manufacturing and Construction
Research Centre): Adaptable Futures, Developing adaptable building products, processes
and people (Unpublished). Loughborough University, Loughborough (2007)
4. Department of Trade and Industry (DTI): Constructing the Future, Foresight Report. DTI,
London (2001)
5. Gregory, C.: What is the value of our workspace, Report L25230-OD1MA-CG250902.
Reid Architecture, London (2004)
6. Larsoon, N.K.: Sustainable development and open building, TG26. International Council
for Research and Innovation in Building and Construction (CIB), Brighton (1999)
43
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7. Cassar, M.: Sustainability and the Historic Environment.
Available from:
http://www.ucl.ac.uk/sustainableheritage/historic_environment.pdf [Accessed 24 January
2008] Centre for Sustainable Heritage, University College London, London (2006)
8. Scheublin, F., Pronk, A., Borgard, A., Houtman, R., Prins, M., Emmitt, S., Otter, A.d.
(eds): Adaptables ‘06, International Conference on Adaptable Building Structures.
Eindhoven University of Technology, Eindhoven (2006)
9. Barlow, J., Childerhouse, P., Gann, D., Hong-Minh, S., Naim, M., Ozaki, R.: Choice and
delivery in housebuilding: lessons from Japan for UK housebuilders. Building Research
and Information, Vol. 31 (2) p.134-145 (2003)
10. Schueblin, F.: Open building in steel, development of a steel framed housing system.
Adaptables ’06, International Conference on Adaptable Building Structures, Vol.1, 2-155.
Eindhoven University of Technology, Eindhoven (2006)
11. Verweij, S., Poleman, W.A.: Evaluation of flexibility options in different housing
projects, an exploration of possible flexibility for second users in multi-storey housing.
Adaptables ’06, International Conference on Adaptable Building Structures, Vol.1, 2-39.
Eindhoven University of Technology, Eindhoven (2006)
12. Barnes, N.: Newways: Presentation for GSK Newways Workshop, 16 October 2007
(Unpublished). GSK, Brentford (2007)
13.
W.E.
Marson
&
Co.
Ltd:
FlexiLab.
Available
from:
http://www.wemarson.co.uk//index.php?view=flexilab [Accessed: 22 January 2008] W.E.
Marson & Co. Ltd, Harlow (2007)
14. Beadle, K. Report on BWM Newways Meeting - 30 October 2007. Civil and Building
Engineering, Loughborough University, Loughborough (2007)
15. Beadle, K. Adaptable Futures Workshop Report (Unpublished). Civil and Building
Engineering, Loughborough University, Loughborough (2007)
16. Beadle, K. Report on GSK Newways Workshop - 16 October 2007 (Unpublished).
Civil and Building Engineering, Loughborough University, Loughborough (2007)
17. Reid Architecture, Buro Happold, Davis Langdon: Multispace: Adaptable Building
Design Concept. Reid Architecture, London (2005)
44
The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Identifying New Construction Demands – A Stakeholder
Requirement Analysis
Jilin Ye1, Tarek Hassan1, Chris Carter1 and Lidewij Kemp2
1
Department of Civil and Building Engineering, Loughborough University,
Leicestershire, LE11 3TU, United Kingdom
2
Draaijer + Partners, Postbus 436, 9700 AK Groningen, Netherlands
1
2
{A.J.Ye; T.Hassan; C.D.Carter}@lboro.ac.uk; [email protected]
Abstract
The construction industry in the European Union (EU) is facing a plethora of challenges, including fierce competition from
other regions of the world. Leading edge technologies, such as innovative industrialisation production technologies, new
integrated processes and advanced intelligent building systems, will enable the development of a sustainable, internationally
competitive and environmentally friendly European construction industry. Although construction – and its significant impact
on quality of life – has received considerable attention in recent years, there is little agreement on how to create an
environment that will allow construction to move from a supply-driven industry to a demand-driven industry focusing on
delivering extra value (sustainability, productivity and flexibility). Within this context, the Industrialised, Integrated and
Intelligent Construction (I3CON) project, partially funded under the EU’s Sixth Framework Programme (FP6), aims to
enable this transformation towards a sustainable European construction industry. It is using industrially produced, integrated
processes and intelligent building systems utilising distributed control systems with embedded sensors, wireless connections,
ambient user interfaces and autonomous controllers. One of the key tasks of the I3CON project is to collect a set of
stakeholders’ requirements – what do clients, designers, contractors, occupiers and communities want from the building of
the future? These findings will be used as metrics against which to measure the success of the I3CON project. In this paper
the state-of-the-art stakeholders’ requirements from European countries are presented. A requirement development process
has been developed which consists of the methodology and procedure, requirement collection, validation and consolidation.
Several key areas have been identified through analysis of the collected requirements, which the research and technological
development (RTD) work within the I3CON project will address. This will lead to new demands for future buildings.
Keywords
Stakeholder requirement, requirement identification, requirement analysis, requirement verification, requirement
consolidation
1
Introduction
The construction industry is the largest single industry in Europe: It accounts for 10.4 % of
gross domestic product (GDP) and more than 50% of gross fixed capital formation. It is also a
major employer, with 2.7 million companies and 26 million direct and indirect employees [1].
It has been recognised that vitality and development in the areas of innovative industrial
production technologies, new integrated processes and advanced intelligent building systems
are critical to the future of the European construction industry [2]. Although construction –
and its significant impact on quality of life – has received considerable attention in recent
years, there is little agreement on how to create an environment that will allow construction to
move from a supply-driven industry to a demand-driven industry focusing on delivering extra
value (sustainability, productivity and flexibility). This is particularly true of the construction
sector in the European Union (EU), which has an extremely diverse industry composed of
architects, contractors, consultants, and material and product suppliers. This diversity has
resulted in isolated components, services and systems within the construction sector [3].
45
Industrialised Construction
Moreover, the sector has a tendency to focus on technical developments rather than on what is
actually needed.
During the past decade, the building industry has adapted slowly to new technologies and
processes compared to other industry sectors like manufacturing. Thus, emerging national and
international initiatives emphasise that the construction industry is challenged not only to
provide a set of physical outputs, but also to offer the most effective long-term support
services to its clients and, at the same time, to respond to society’s growing requirements for
sustainability [4]. This creates a new perspective that requires a radical change in thinking
towards a demand-driven, innovative, sustainable and competitive industry.
In order to address this radical transformation from the current “craft and resource based
construction” towards industrialised, integrated and intelligent construction, revolutionary
construction and production technologies are needed. These will need to deliver flexible and
adaptable building space that uses fewer resources and provides an optimum environment for
occupants, improving their quality of life and productivity. They are regarded as the key
drivers for change and improvement of the construction industry in the future.
This paper investigates the state-of-the-art stakeholders’ requirements from European
countries in the construction sector on an industrialised, integrated and intelligent construction
concept and derives the key requirements using a requirement development approach for life
cycle costing, energy management, flexibility, building processes, and comfort and customer
orientation. This provides the starting point for the vision/focus of the I3CON project.
2
Stakeholders Classification and Identification
A value stakeholder network consisting of authorities, end-users, owners and service
providers was identified and established, through a series of workshops and brainstorming
sessions, to form the input body for collecting and structuring the requirements. Based upon
this network, a list of stakeholders and their categories were developed (see below) which
provides good coverage of all stakeholder types:
A. Client – individuals or organisations that initiate the building process/generate the need
for a building.
B. Professional team – individuals or organisations that are involved in the project
management, design, planning, insurance, and contractual and financial control of the
building process. (The key differentiator between these stakeholders and those
stakeholders in category C below is that these people do not construct or manufacture
building elements)
C. Constructors – companies that are involved in building, testing and commissioning of the
building.
D. Occupants – individuals or organisations that use the building.
E. Occupant support services – individuals or organisations that are responsible for the ongoing maintenance & operation of the building and the functions that take place within it.
(Major refurbishments are not included as they are considered as a new building cycle.)
F. Regulatory bodies – organisations that provide and enforce codes & standards. These
codes and standards constrain other stakeholders.
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
G. Infrastructure – physical & social infrastructures around the building.
Kemp et al [7] provide more details about this classification and examples of stakeholders
in each of the seven categories (e.g. housing associations and private developers in the
category of Clients (A)). They also included a matrix with stakeholders, building types and
phases in the building process (based on the building process protocol).
The stakeholder requirements were derived from across these stakeholder types, so as to
ensure a “common view” on the requirements for innovation in the industry. This has been
finalised with feedback received from the project partners involved in various work packages,
together with comments made during group discussion meetings.
3
The Requirement Elicitation Process
Based upon the above stakeholder classification, a comprehensive requirement elicitation
process was created, which comprises a methodology and procedure, requirement collection
and validation and consolidation of requirements. This is summarised and illustrated in Fig. 1.
Stakeholder
expectation
Capture
Trends in EU
countries
Interview summaries
Analyze
State-of-the-art
USA and Canada
Background information on trends
Verify
Hamburger
model
Consolidate
Assessment criteria
Fig. 1. Requirement development process
During definition of the methodology and procedure, a multi-dimensional framework [6]
was developed to structure the stakeholder requirements captured in the next step. This
consists of four dimensions: stakeholder categories; European regions; technology subjects
and building categories (as shown in Fig. 2). The dimensions of building categories, European
regions and stakeholder categories are used to provide further insight into the various
47
Industrialised Construction
stakeholders’ requirements, rather than to limit the stakeholder requirements from some
specific domains. For instance, good coverage of European regions is important to avoid
capturing requirements relevant to only certain countries. The technology dimension was
added so that requirements can be mapped against technical research and solutions delivered
by technological work packages (WPs) within the I3CON project.
Fig. 2. Framework dimensions
In order to obtain high quality, precise and detailed information on stakeholder
requirements – rather than large volumes of vague information – it was decided to collect the
stakeholder requirements by undertaking formal interviews instead of sending out
questionnaire survey. Using interviews to gather the information instead of a questionnaire
leads to higher quality information, because the interviewee was able to clarify his / her
answers, for instance by giving the context that was underneath a certain answer.
To verify the stakeholder requirements collected in the EU region, the state-of-the-art of
stakeholder requirements in other major markets like the USA and Canada were reviewed by
the authors through a desktop study [5]. Comparison was made and this confirmed that the
ongoing I3CON project is addressing the main and relevant issues in its RTD work.
The Hamburger model [8] was employed to consolidate the verified requirements. The
results from this process were communicated to the relevant I3CON technical WPs,
illustrating the relationships between the requirements and the expected impacts and benefits
of the relevant technical WPs. This forms the fundamental base for the success of the I3CON
project, and will provide assessment criteria to benchmark the outputs of the technical WPs
against stakeholder requirements. The identified requirements can be seen as the “program of
wishes” from key stakeholders in the European construction industry to achieve innovation of
product and process in the building industry. The technical solutions to these requirements are
sought in technical WPs within the I3CON project.
4
Voice of the Stakeholder
In order to obtain stakeholders’ opinions regarding the specific features of I3CON, current
industry trends and important factors, their main concerns, ideas for possible changes and
their requirements and needs, a total of 72 formal interviews were conducted in 6 different
countries (Spain, Turkey, Netherlands, Germany, Finland and the UK). The interviewees were
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
from a range of different roles in building projects, and were classified in categories from A to
G, as discussed in Section 2.
The interviews resulted in two types of information, namely the views and opinions of the
interviewed stakeholders (qualitative results) and their rating of given factors and trends in the
current building industry (quantitative results). This combination of qualitative and
quantitative data increases the value of the information collected. The former was obtained by
asking open questions during the interviews, to which the interviewees could provide answers
and explanations, which provides valuable data, but is more difficult to compare and analyze.
The latter (quantitative data) was collected by sending a list of factors and trends to each
interviewee beforehand, and asking them to rate the importance of several given factors
(subjects in the building industry) and trends.
4.1 Importance of Factors
To prioritise issues in the current building industry, the interviewees were asked to rank the 5
most important factors from a given list of factors, as shown in the left part in Fig. 3. The top
5 factors were: 1. energy reduction, 2. building lifecycle economy & building performance, 3.
sustainability (in its broadest context), 4. work productivity / comfort and wellness (for end
users), and 5. flexibility (e.g. adaptability in terms of easily modifiable buildings), as shown
in the right part in Fig. 3. Less important factors indicated by the stakeholders included:
capital cost of construction, cost efficiency/ reduction during construction and construction
time, even though these are often the factors that project management concentrates on. The
bars used in Fig. 3 have graded shadings, from black to grey to white. These refer to the
ranking number that was given to the factor: black stands for “1” (most important), various
shades of grey for “2”, “3”, “4” and “5” respectively. The white part of the bars in Fig. 3
means the factor was not named in the top 5 by the interviewees.
4.2 Importance of Trends
The interviewees were also asked to rate a given list of trends in terms of importance. These
trends sit on a more detailed level than the factors discussed in Section 4.1. And they are
categorised in six main areas in this paper as listed below:
• Economic/financial
• Technological/building process
• Building functionality
• Ecological
• Social
• Regulations
Each category contained several trends and, for each, the interviewees were asked to select
the 3 most important based upon their knowledge and experience. This data permitted further
consolidation of the requirements; the factors and trends identified as very important by all
stakeholders are further defined and translated into requirements that map onto the visions and
goals in the other (technical) WPs. For example: “Focus on lifecycle costing” is rated as an
important trend by the stakeholders. Linking it to Performance Based Business Models can
lead to the requirement that the business model that is developed, is life cycle oriented.
Linking it to New Components and Production Methods can lead to the requirement that life
cycle costs of components should be low. Kemp et al [7] described the main results in detail
with different bar charts for each category listed above.
49
Industrialised Construction
other (not stated above): ….
social acceptability
durability
safety
flexibility (e.g. adaptability in terms of easily modifiable
buildings)
work productivity/ comfort and wellness (end users)
(range in) quality of construction (material, etc.)
construction time
construction methods (i.e. on-site or prefabrication)
energy reduction (during operation of the building)
sustainability (in its broadest context)
cost efficiency/ reduction during construction
capital cost of construction
building lifecycle economy & building performance
0%
10%
20%
30%
40%
50%
Fig. 3. Importance of factors
4.3 Main Findings from Open Questions
The holistic questionnaire used in the formal interview consisted of a standard set of open
questions that covered the six main categories described in Section 4.2. In this way more
valuable/qualitative knowledge and information has been captured than possible using closed
questions. Interview summaries sorted by countries were produced by the I3CON partners
involved in this task [7]. The main findings from interviews with open questions can be
summarised as follows:
Industrialisation
•
One of the major trends that will become even more important in the future
•
Innovation on the subject of industrialization is important, since the construction process
has been the same for over 50 years
•
Increase use of prefab/standardised building elements to increase speed
•
Will bring cost and time advantages and will increase quality
Integration
•
Today’s building processes are highly fragmented (from procurement to in-use); there
should be more cooperation between organizations involved in building projects
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
•
A global picture of the whole process is missing: building projects became more complex
and more specialized, and contain more interfaces (problems arise with coordination and
the decision making process)
•
Maintenance issues not sufficiently thought through in design
Intelligent buildings
•
High performance = intelligent = good environmental performance
•
Top measure of building performance = total energy consumption; but most important
thing a building can do is to make people in it productive; in terms of costs this far
outweighs any other costs
•
Necessary to be energy-efficient
•
Automation is obligatory at a certain level for low-energy technologies
•
Users need to learn how to handle such products (training can be offered); higher level of
automation requires higher skilled labour
•
Intelligent buildings can also mean intelligent concepts: sustainability, flexibility (facades,
building technology, adaptable interior)
Main problems
•
Changes are necessary in regulations, mentality, businesses, etc. in order to facilitate
innovation
•
Lack of flexibility in buildings: not built for specific user needs, then tweaked for specific
user needs – leading to sub-optimal performance for all users
•
Current procurement: time consuming, complex tendering – wasteful
•
While looking to make buildings more sustainable, organizations would be reluctant to
use highly innovative technology as it is seen as too risky – unknown on-going costs,
reliability, etc.
•
Buildings change less quickly than social trends
•
Increasing specialization: the complete overview is lost so that cooperation becomes more
difficult between specialists (each with their own very narrow focus)
•
Tender, approval and decision making processes take too long and require excessive
administration
•
The industry, and innovation within the industry, is mostly supply-driven
•
Requirements are proposed either too late or at the wrong time (Ecology, User,
Flexibility)
•
Good management / planning from beginning to end is missing (consider what the
important criteria in each construction phase are, and if all important aspects were
considered)
Market chances
•
Regulation is essential for innovation
51
Industrialised Construction
•
Recently, it has been demonstrated that if you offer better quality in terms of what the
Client wants, and you really show the quality, Clients will pay for it. Opportunity is to
improve level of service to clients
•
A large percentage of building projects are the re-use of old buildings, therefore finding
smart solutions for refurbishment is important
•
Buildings conceived from design phase to accommodate different uses, keeping in mind
flexibility
•
Projects to be assigned to the best integral offer, with the best technical, resources and
economical offer, and not just the lowest price
•
Opportunity: high awareness of environmental issues
•
Design from ‘cradle to grave’
•
A high performance building is one that is used for the maximum hours a day and days in
a year; efficient to run and comfortable to work in
5
Requirement Verification
The requirement verification process checks the redundancy and inconsistency of stakeholder
requirements captured by the I3CON partners. The goal of this process is to produce
requirements that are consistent, valid in terms of feasibility and necessity, and are
quantifiable and verifiable.
In addition to the European region, stakeholders’ requirements from other major markets
like the USA and Canada were also studied. Additional comparisons to these major markets
have been conducted [5] to ensure that the I3CON project considers the main issues relevant
to its three “I”s and incorporates them within its programme of RTD. The three “I”s are:
•
Innovative Industrialisation production technologies for the construction sector;
•
New Integrated processes for the construction sector;
•
Advanced Intelligent building systems for the construction sector
6
Requirement Consolidation
The aim of the requirement consolidation process was to actualise the stakeholder
requirements captured by the I3CON partners, provide a basis for understanding,
communicating and appropriately linking the different requirements to the corresponding
work packages within the I3CON project. In order to get from stakeholder expectations to
consolidated requirements, the following three steps were taken:
•
Prioritize requirements by importance given to them by interviewees
•
Translate stakeholder expectations to requirements
•
Link requirements to tasks in technical WPs
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
6.1 Requirement Priorities
To prioritise captured requirements discussed in Section 4, the top 5 trends identified in the
six main categories were used [9]. All requirements were prioritized, according to the
importance that the stakeholders gave to them. They highlighted the most important and
relevant subjects relating to the vision and focus of the I3CON project.
From the results discussed in Section 4.2, a list of the most important trends per category –
in the opinion of the interviewees (all countries and all stakeholder types) – is shown in Table
1. The stakeholder expectations are listed in order of importance, starting with the most
important per category.
6.2 Translating stakeholder expectations to requirements
The next step taken was to translate the stakeholder expectations, which can be described as
‘functional wishes’, to technical requirements, which the tasks in I3CON technical WPs will
address. The ‘Hamburger Model’ approach [8] was applied to affect these translations.
This model distinguishes a ‘Functional Concept’ on the demand side and ‘Solution
Concepts’ on the supply side (see Fig. 4). In other words, the ‘Functional Concept’ states in
‘user language’ WHAT is required and WHY it is required and the ‘Solution Concept’ states
in terms of technical specifications HOW the requirements are supposed to be met.
Fig. 4. The Hamburger Model [8]
53
Industrialised Construction
Table 1. Importance of stakeholder expectations
Requirements
Requirements
A
Economic/ financial
D Ecological
1
Focus on life cycle costing
1
Low-energy buildings
2
Focus on energy costs
2
Focus on climate changes
3
Focus on energy management
3
Increasing focus on energy efficiency
4
Increase flexibility and reduce costs
4
Water management – reuse of rain water
5
Focus on total cost of ownership
5
Changes in living environment–higher expectations on
well-being & hygiene
B Technological/Building process
E Social/ Cultural/ Demographical
1
New contract models
1
Social added value; optimal focus on demands & desires
in society
2
New building processes
2
Increase smaller/ single dwellings
3
Reconstruction, modernisation of old
buildings
3
Improved knowledge infrastructure
4
Increasing automation
4
Increasing life-span of population–implications for
housing requirements
5
Industrialised construction
5
24-hours economy
C Building Functionality
F Regulations/ Political
1
Flexible buildings to adapt to future
changes of use
1
Changes in the legislation – The Energy Performance
Building Directive
2
New solutions to existing building stock
2
Quality standards & Certificates
3
Multi-purpose/ multi-use
3
Litigious society – impact on design and management of
buildings
4
Impact of flexible working on housing
and office facilities
4
Changes in the legislation – Indoor Air Quality
5
Residential complexes – incl. shopping,
entertainment and recreational
5
Specific regulations for educational buildings
The ‘Functional Concept’ in the I3CON project represents the stakeholders expectations
(captured through interviews in the European countries), and the ‘Solution Concept’ consists
of solutions to the ‘functional needs’ (to be developed by the I3CON project). Finally the
‘Solution Concept’ should comply with the ‘Functional Concept’.
The performance approach offers a solution using ‘performance language’ [10] as an
intermediate step between functional needs and requirements and technical solutions (see Fig.
5). On the demand side, functional needs are translated into performance requirements. These
are facility or product related requirements, expressing what properties the built facility
should have to facilitate the intended use. On the supply side the technical specifications are
translated into performance specifications, expressing the measured or predicted properties of
the offered solution.
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Fig. 5. The performance language
Once both the Functional and the Solution Concepts are translated into ‘performance
language’ (assessment criteria), a comparison between demand and supply can take place. For
example, the assessment criteria “Flexible buildings to adapt to future changes of use” is
translated into the different ‘languages’ as shown in the example below:
•
Functional needs: the end user of an office building wants to be able to make more work
places available when the number of employees increases. They want flexibility in the
use, to adapt to future changes.
•
Performance requirements: in the design of the office buildings, meeting rooms (4
persons) have the same dimensions as a (closed) office for 2 desks.
•
Technical specifications: standard dimensions are used, e.g. 3.6 metre x 3,6 metre for the
meeting room/ closed office space.
•
Performance specifications: by only changing the interior (furniture), the space is easily
adaptable to the growth in number of employees.
•
The comparison/matching between Functional and Solution concepts is part of the peer
review work in the I3CON project, which checks the quality of the outcome in relevant
WPs.
6.3 Linking Requirements to Technical Tasks
After the most important stakeholder expectations were identified, they were linked to the
other work packages in the I3CON project to which they apply, e.g. the expectation of
stakeholders to develop new contract models applies to Performance Based Business Models
in which new business models are researched. A matrix mapping approach was used to create
the links between requirements and tasks. An “X” means there is a link, an “A” means that the
link (for that WP or task) is the most important. The identification of the links and the
selection of the 5 most important (“A”s) was undertaken in cooperation with Stakeholder
Requirements partners and WP leaders, and the main results are shown in Fig. 6. Kemp et al
[9] provides a more detailed description of this approach.
55
Industrialised Construction
4
5
6
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1
2
3
4
5
6
F
1
2
3
4
5
6
Changes in the legislation, EU essential requirements - Indoor Air Quality
(IAQ)
Specific regulations for educational buildings e.g. insulation, air tighness
etc.
Other, per country (if applicable)
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Fig. 6. The matrix mapping results
56
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X
A
A
X
A
A
X
A
X
X
X
X
A
X
A
X
A
A
X
X
A
A
A
A
T6.5 Integration and testing
X
X
A
X
X
Intelligent catalogues of
components and models
A
X
X
X
X
A
T6.4
X
X
X
A
A
X
X
X
X
X
T6.3 Ambient user interfaces
A
A
X
X
Simulation engine and
toolset
X
X
X
X
A
T6.2
A
X
X
T6.1 Building services model
X
X
X
X
WP6 General
X
X
A
Service integration
management
X
X
A
A
T5.5
X
A
A
X
X
X
A
WP6
T5.4 Service configuration tool
X
A
X
X
Mobile productivity tools
and methods
X
T5.3
X
Concepts and methods for
service engineering
A
X
A
Control & monitoring
systems
A
X
X
T4.5
X
A
A
Structural components,
fittings, envelope systems
X
X
X
X
X
X
X
T4.4
X
X
X
X
X
X
X
A
Innovative energy efficiency
products/concepts
X
X
T4.3
A
X
A
X
Future technology
identification & roadmap
A
X
T4.2
X
X
System requirements to
develop smart components
A
X
T4.1
X
X
T5.1
2
3
4
5
6
C
1
2
3
4
6
D
1
2
3
X
WP4 General
X
X
X
X
T3.5 Building systems concepts
X
A
X
X
T3.4 Sensor networks
X
X
X
X
A
Integrated Building
Automation and Control
X
X
X
X
A
T3.3
A
WP5
Space modular concepts
and reference solutions
A
WP4
T3.2
Operational business
processes
T2.3
A
T3.1 Overall BS architecture
LC performance model,
metrics & criteria
T2.2
2
3
4
5
6
B
1
Economic/ Financial
Focus on life cycle costing (A2) (A4) (A5) (how do all stakeholders
participate in the model)
Focus on energy costs
Focus on energy management
Increase flexibility and reduce costs
Focus on total cost of ownership
Other, per country (if applicable)
Technological/ Building process
New Contract Models (Organisation models to achieve the goal of all
participants) (e.g. PPP)
New building processes (e.g. procurement)
Reconstruction, modernisation of old buildings
Increasing automation (e.g. intelligent buildings)
Industrialised construction
Other, per country (if applicable)
Building functionality
Flexible buildings to adapt to future changes of use
New solutions to existing building stock
Multi-purpose/ multi-use
Impact of flexible working on housing and office facilities
Other, per country (if applicable)
Ecological/ Environment
Low-energy buildings
Focus on climate changes
Increasing focus on energy efficiency - use the sun: e.g. lots of windows
on the southern side, no windows on the northern side
Water management / water supply - re-use of rain water
Changes in living environment - higher expectations on well-being and
hygiene
Other, per country (if applicable)
Social/ Cultural/ Demographical
Social added value; optimal focus on demands & desires in society
Increase smaller / single dwellings, small affordable family units
Improved knowledge infrastructure
Increasing life span of population - implications for housing requirements
(e.g. facilities for elderly)
24-hours economy
Other, per country (if applicable)
Regulations/ Political
Changes in the legislation, EU essential requirements - The Energy
Performance Building Directive
Quality standards & Certificates
Litiguous society - impact on design and management of buildings
WP3 General
Reference model for valuecreating business models
X
WP2 General
A
1
WP3
T2.1
WP2
The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
7
Conclusions
In this paper, the authors addressed the state-of-the-art stakeholders’ requirements from
European countries in the construction sector. A requirement development process was
developed, which comprises methodology and procedure, requirement collection, validation
and consolidation of requirements. Several key areas have been identified through the data
analysis of the collected requirements, which the main RTD work within the I3CON project
will address. This has been achieved by creating a linkage between the main findings and all
technical tasks through a matrix mapping approach. This led to a fundamental base for
creating new construction demands for future buildings on which the I3CON project will
focus.
Future work will focus on using new metrics generated from these findings to further guide
the ongoing RTD work in the I3CON project.
Acknowledgement. This research work is from the I3CON Integrated Project, partially
funded by the EC under its Sixth Framework Programme (FP6). The authors gratefully
acknowledge the support of the EC and the contributions of all the partners.
References
1. Construction in Europe. Located at http://www.fiec.org/Content/Default.asp?PageID=5.
Accessed on 30 January 2008.
2. Construction Industry Training Board, Rethinking Construction Workshop, 26th March
2002, CITB National Conference
3. Collaboration – The Way Forward for UK Design Activities – Working Group 2 – 13-14
February 2003, Marriott Arden Hotel, Meriden, UK.
4. ManuBuild Project Newsletter Issue 1
5. J. Ye, T. Hassan et al. Actualisation of the State of the Art Stakeholder Requirements.
Internal research report, Department of Civil & Building Engineering, Loughborough
University, UK. May 2007.
6. L. Kemp, J. Camphuijsen, et al. Deliverable 1.1-1. Stakeholder Requirements:
Methodology and Procedure. I3CON Final Research Report, November 2007.
7. L. Kemp, J. Camphuijsen, et al. Deliverable 1.1-2. Stakeholder Requirements: Captured
Requirements. I3CON Final Research Report, November 2007.
8. F. Szigeti, G. Davis and M. Jasuja. Performance Based Building: Conceptual Framework.
Final Report. EUR 21990 ISBN 90-6363-051-4. October 2005.
9. L. Kemp, J. Camphuijsen, et al. Deliverable 1.1-3. Stakeholder Requirements:
Consolidated Requirements. I3CON Final Research Report, January 2008.
10. L. Pham, P. Boxhall et al. Performance Based Building Design Process – PeBBu Domain
Agenda and Future Development Needs. Proceedings of the 2nd International Conference
of the CRC for Construction Innovation: Clients Driving Innovation: Moving Ideas into
Practice. March 2006, Gold Coast, Australia.
57
Industrialised Construction
58
The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Automatic Manufacturing of Unique Concrete Structures
Dorthe Mathiesen, B.Sc. ,Project Manager1, Thomas Juul Andersen, Cand.Arch.1, Lars Nyholm Thrane, Civil
Engineer, Ph.D.1
1
Danish Technological Institute, Concrete Centre, Gregersensvej, 2630 Taastrup, Denmark
Abstract.
Today’s concrete architecture is often dominated by repetitiveness and recognisable geometries like squares and rectangles.
Digitally designed and extraordinary concrete architecture involves excessively high construction costs, due to the production
methods based on craftsmanship used. To lower the cost and to utilize the unused potential of unique concrete structures
research in new industrialised methods is required. The research in the project “Unique Concrete Structures” involves new
moulding materials, robot processing techniques, CAD/CAM integration, form filling processes with concrete. To be able to
develop and test new industrialised methods of manufacturing unique concrete structures, a High Technology Concrete
Laboratory equipped with a robot cell and a fully automatic concrete mixing plant has been established at the Danish
Technology Institute.
Keywords
Construction Automation; Robot Technology, Concrete Technology, Digital Architecture, Mould materials, Formwork
1. Introduction
Many architects see concrete as a fundamental construction material but also as a material,
which offers unique opportunities in terms of shaping; however, the nature of conventional
concrete production and technology has set up clear limitations to the aesthetic possibilities.
Thus, tools are strongly needed to overcome the present barriers, which prevent realization of
the architect’s visions for future concrete constructions.
The Danish project “Unique Concrete Structures” deal with this issue. The project runs in 3
years and started its activities in January 2007. The aim of this project is to find solutions for
mass customisation of concrete constructions. This requires new ways to build unique moulds
by the use of robots, and development of tailor-made concrete with special, engineered
properties in the fresh state, that will spread in the formwork and around even complicated
reinforcement arrangements by its own weight.
The project gathers leading Danish expertise within architecture, concrete technology, and
robot technology. The challenge is to create opportunities for a more interesting and
distinctive architecture within a reasonable cost frame. The participants in the project are
Danish Technological Institute (concrete technology, robot technology, mould materials),
University of Southern Denmark (robot technology), School of architecture in Aarhus
(architecture), Spæncom a/s (pre-cast concrete structures), Unicon a/s (ready-mix concrete),
Giben Scandinavia a/s (robot technology), Paschal Danmark a/s (formwork systems) and MT
Højgaard a/s (contractor). The project is financially supported by The Danish National
Advanced Technology Foundation.
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Industrialised Construction
2. Background
Concrete is the most used construction material in the world. Annual global production of
concrete hovers around 5 billion cubic yards [1]. Despite the unique fresh state properties of
concrete allowing the concrete to take any given shape, the concrete architecture that we
know today is often dominated by repetitiveness and recognisable geometries like squares and
rectangles. Spectacular concrete architecture is rarely seen, and almost only in connection
with extraordinary buildings, where the construction costs have been excessively high, despite
of concrete being a cheep building material. Examples of project like these are the extension
of the art museum Ordrupgaard in Copenhagen by the Iraqi / British architect Zaha Hadid
(fig. 1) and The Tenerife Opera House by the Spanish architect Santiago Calatrava.
Fig. 1. Today’s concrete architecture is often characterised by repetitions. Only rarely do we see more interesting
and unique use of concrete, and then only in extraordinary buildings as for example the extension of the art
museum Ordrupgaard in Copenhagen.
One of the reasons for the high expenses is to be found in the production of concrete
structures. Here the development has not experienced essential innovation since the
industrialisation in the first half of the 20th century, which means that the production methods
still are based on craftsmanship. To this must be added that the standardized formwork
equipment in steel and wood do not have the needed flexibility to adjust into unique
geometries. Handmade moulds for unique buildings are both difficult to produce, time
consuming and expensive. The costs for preparation of the formwork can amount to 75% of
the total costs.
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
To lower the cost and to utilize the unused potential of concrete for unique structures,
innovative development and usage of the construction industry is required. To this must be
added implementation of already known technologies and manufacturing process known from
other industries. In connection to this, especially the progress on SCC (Self Compacting
Concrete) and the expansion within the field of industrial robots for one-off production are of
interest. Succeeding in bringing these technologies together will provide an outstanding
opportunity for a technological breakthrough in the concrete industry.
In connection to this project, the Danish Technological Institute has established a new HighTechnology Concrete Laboratory. The laboratory is equipped with a robot cell and a fully
automatic concrete mixing plant. This laboratory makes it possible to develop and test new
industrialised ways of manufacturing unique concrete constructions. Even though the robot
has a limited working field (2*2 m2), the manufacturing procedures developed can be brought
into full-scale and cover a larger working area e.g. by introducing several track-mounted
robots.
Fig. 2. The High-Technology Concrete Laboratory at the Danish Technology Institute.
2.1. State of the Art
Rapid manufacturing has developed through the aerospace and automotive sectors, and is now
a growing feature of today’s construction industry. One of the most striking developments is
the introduction of Digital Fabrication, the application of large scale CAD/CAM (Computer
Aided Design / Computer Aided Manufacturing) techniques for the creation of building
structural components and facades [2]. Following is a few examples of projects where the
technologies have been used to create unique architecture.
An example of manufacturing of major structural components in concrete by the use of CNC
(Computer Numeric Control) milling is the Zoolhof Towers in Dusseldorf, Germany by the
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Industrialised Construction
American architect Frank Gehry. The undulated forms of the loadbearing external wall
panels, made of reinforced concrete, were produced using blocks of lightweight polystyrene
which was shaped in CATIA and CNC milled to produce 355 different curved moulds that
became the forms for the casting of the concrete [3].
Another project that deals with CNC milled polystyrene moulds is Big Belt House project in
Meagher County, Montana by the American architect William Massie. The formwork
consisted of approximately 1500 individual pieces of CNC milled polystyrene. This great
puzzle was then transported and assembled at the construction site. Concrete was then poured
into these forms, creating the walls of the house [4].
In order to research in digital fabrication processes, the ETH Zurich Department Architecture
has developed a fully flexible fabrication installation. Using modified industrial robots, the
research involves entirely new approaches to e.g. bricklaying. The installation opens up new
possibilities to fabricate brick walls which could not have been conceived or fabricated
manually [5]. The techniques were used to design and fabricate 400 square meters of brick
facade for a functional building of a winery. The single bricks were laid out in a predefined
grid and were merely rotated around their centre point by the robot.
3. Content
The innovation of the project is the interdisciplinary approach with leading research and
industrial partners bringing concrete technology, robot technology and architecture together.
The project is divided into 8 subprojects (fig. 3).
Fig. 3. The innovation of the project “Unique Concrete Structures” illustrated by the relations between the 8
subprojects.
3.1. Architectonic Statement
Architecture plays an important role in our culture. Through history, architecture has always
reflected the technological possibilities of an epoch. Think of the bridges in the early 20th
century with long spans due to the invention of reinforced concrete and the big structuralised
housing projects in the middle of the 20th century due to the industrialisation of pre-cast
concrete elements. The latter example could just as well have been the description of today’s
situation, despite the almost unlimited possibilities with ICT (Information and
Communications Technology).
New digital tools for 3D shaping and form optimization have set a new agenda for the future
architecture. The computer allows the architect to design a digital architecture that is beyond
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
imagination. The research in this subtask involves describing and visualising hypothesis of
the needs and demands to the future concrete architecture and thereby a new architectonic
idiom, characterised by the parametric design tools used.
3.2 Flexible Formwork Systems
Traditional formwork systems are typically a unit, where the actual formwork material is an
integrated part of the formwork system. This project distinguishes the system from the
material because of their different functions and properties. This means, that the formwork
system in this project is the bearing structure of the formwork, which both can carry the load
from the wet concrete and the hydrostatic pressure.
The research will focus on analysing and optimising existing formwork systems and if needed
also development of completely new systems. Whether the final formwork system is an
existing, new or a combination of the two is not important. The essential property of the
system is that it has the needed flexibility in order to comply with the demands for total
design freedom. To this must be added that the formwork system both can be used in a precast concrete production and on a construction site.
3.3 Formwork Materials
Opposite the formwork system, which is mainly focusing on static aspects, the formwork
material is focusing on design. The formwork material shapes the concrete both in overall
geometries and down to surface textures.
The research will focus on analysing both traditional and new formwork materials. These are
analyzed in relation to aspects like environment, economy, strength, flexibility and
architectonic possibilities.
The project divides the formwork materials into two categories: A basic material and a
coating/paste. The basic material is manufactured into the requested geometry. It could be
wood, polystyrene, moulding sand, paraffin etc. This manufactured formwork material can be
used in the formwork system as it is or a coating can be applied. A coating is typically a
release agent like form oil but in this project it is also materials which can give new surface
properties to the basic formwork material. It could be silicone, latex, epoxy, that will be
sprayed or pasted on to the surface. The coating opens up new possibilities to achieve
different surface textures.
3.4 Processing Techniques
The main tool for manufacturing the formwork materials is a 6-axis robot. The potential of the
robot regarding automation of i.e. the cutting, milling, melting and lifting processes will be
exploited in the project. Based on the different tasks the robot can change its tool with the
automatic tool changer. This gives the robot the needed flexibility in order to develop and
verify the full process in fabrication of unique concrete structures.
The formwork materials are decisive for the choice of tools and processing techniques
applied. Research will involve mathematical modelling in order to carry out the required
processing operations.
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Industrialised Construction
3.5 Software
To be able to translate the architects CAD drawing into a work plan for the robot, CAM
software is needed. In this project Delcam PowerMILL is used to perform this translation.
Initially, PowerMill is used for planning of milling strategies. Later on, the possibilities of
other processing techniques will be exploited.
The toolpaths from PowerMill are translated into joint angles of the robot. However, as there
may exist more than one solution for the same robot position it is important to develop
software to ensure and verify that the robot positioning is actually physical possible.
The research will focus on robots for single production, where the robot control unit
automatically calculates the movement of the robot based on input from a 3D CAD
production drawing. Based on mathematical models known from spray coating it is pursued to
develop accurate mathematical models for formwork processing and formwork coating.
Developed mathematical models can lead to a system of automated generation of robot paths.
3.6 Form Filling
New and complex geometries give new challenges to the SCC in order to fill the form
properly. The main research in this subproject is to simulate the form filling using CFD
(Computational Fluid Dynamics) technology in order to tailor the theological properties of the
SCC. Based on the results of these investigations, the concrete composition and the casting
techniques will be optimised.
A newly finished PhD project has revealed the potential of the use of CFD technology in
combination with a micro mechanical model for simulation of the flow of SCC in a mould.
This model strategy will be improved and optimised with focus being on form filling of
formwork with complex geometries. It is expected that these complex formwork geometries
will put even higher demands on the properties of the concrete.
3.7 Laboratory
Formwork materials, processing techniques and form filling are tested in The HighTechnology Concrete Laboratory at Danish Technology Institute.
3.8 Full Scale
By using the technologies developed in the project and tested in the laboratory, geometries
from the Architectonic Statement are to be made in full scale.
4. Results
So far, the project has shown some interesting results, particularly in the first three
subprojects 4.1 Architectonic Statement and 4.2 Formwork Materials. Due to the projects
activities still being in an early phase, few mentionable results in the rest subprojects have yet
occurred.
4.1. Architectonic Statement
The architectonic statement was finished in the first half of 2007. Through a mapping of the
history of concrete architecture from the Romans to today and a near future, the statement
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
gives some answers, in which direction the concrete architecture will move. It concludes that
the future will introduce a new amorphous digitally created architecture only possible to build
with new industrial production methods. This means that new industrialised technology in the
production chain will update the architectonic design possibilities and thereby be able to
match today’s technological possibilities with ICT.
4.2. Formwork Materials
An extensive analysis of potential formwork materials has ended with a detailed list, which is
the starting point for the test activities in laboratory. The list of potential formwork materials
includes plywood, polystyrene, PU-foam, paraffin, latex, acryl, mould sand, clay and many
more. Coating materials is represented by epoxy, bio resin, silicone, EVA-foam and many
more.
The first material tested was polystyrene. The material was tested for compressive strength in
order to make mathematical models for strain due to the hydrostatic pressure and uplift from
the wet concrete. Afterwards different milling tools were tested at different milling speeds in
order to determine the optimized speed and tools in relation to the requested surface of the
milled polystyrene.
After the initial testing a block was milled by the robot into a requested mould and afterwards
filled with SCC. This test not only showed possibilities with the geometry but also the
potential to integrate graphic milled into the mould and pictured on the concrete as a
depression or elevation (fig. 4). When casting in polystyrene moulds the surface of the
concrete becomes rough. Tests with different coatings in order to achieve smoother surfaces
of the concrete was made and with promising results (fig. 5). The test project was carried out
with an open mould, which results in a plane backside on the final concrete element.
The natural step afterwards is to make closed moulds with more complex geometries.
Therefore, full-scale tests have been planned, where the full potential of the project will be
exploited. This involves two wall structures in complex geometries, where the formwork is
composed of polystyrene milled formwork and a traditional formwork systems.
Fig. 4. The test with polystyrene illustrated by the CAD model, the milled mould and the final concrete element.
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Industrialised Construction
Fig. 5. A robot milled polystyrene mould coated with a thin rubber on one side. The cast concrete surface shows
the great contrast in surface textures.
5. Conclusions
Different projects show the big potential in integrating automated and industrialised
production methods into construction. The technologies are individually not new, but the
transferring of technologies and bringing them together into construction and concrete
production specifically could create a breakthrough in the concrete industry. One of the big
challenges will be to prepare and implement the technologies in the production of concrete
structures.
But to fully utilize the unused potential of concrete, not only the shaping of concrete but also
the surface texture of the concrete has to be explored. This involves research in many
different formwork materials and coatings to achieve different surface qualities and also
different processing techniques in order to achieve graphics on the surface. The project
“Unique Concrete Structures” deal with these issues and if succeeded the project can show
directions for the concrete industry how to meet the demands for a new digitally created
concrete architecture in the future.
References
1.
2.
3.
4.
Cement Association of Canada / Available: http://www.cement.ca
R.A. Buswell et al. / Automation in Construction 16 (2007) 224-231
Marc Aurel Schnabel / Computer Graphics for Architects in 2001-02, September 2001
Parker Browne Eberhard, University of Cincinnati, Traces of Materials and Process, 2003
/ Available: http://www.ohiolink.edu/
5. Gramazio & Kohler, ETH Zurich Department Architecture / Available:
http://www.dfab.arch.ethz.ch
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Exploring the Types of Construction Cost Modelling for
Industrialised Building System (IBS) Projects in Malaysia
Nor Azmi Ahmad Bari¹, Mohamad Razali Abdul Kadir¹,
Napsiah Ismail², Rosnah Mohd Yusuff²
¹Department of Civil Engineering, Universiti Putra Malaysia
²Department of Mechanical and Manufacturing, Universiti Putra Malaysia
Abstract
Cost estimating is an important activity that be monitored at different phases of the building construction process, i.e. starting
from the inception and feasibility study phase of the project to the preliminary and detailed design phases, and right towards
project completion. This study attempts to provide information on the types of cost estimation model being adopted by
quantity surveyors in Malaysia, in particular the pre-tender cost estimation process of construction projects using the
Industrialised Building System (IBS). The findings revealed that the more traditional types of cost estimation model continue
to be in widespread use irrespective of organizational size and type. On a lesser degree are the application of value
management and resource-based models, while other newly-developed ‘new wave’ models such as artificial neural network,
fuzzy logic, and environmentally and sustainable development cost models apparently did not receive the desired level of
corroboration necessary for a modern method of construction such as IBS.
Keywords
Cost estimation, Industrialised Building System, Construction project, Cost modelling, Innovation.
1.
Introduction
Cost estimation in construction projects is a factual process designed to give a reliable
prediction of its financial cost [2]. As a prerequisite, the process naturally requires the project
management team to have sound technical knowledge of the estimation procedure and
planning, extensive practical experience, as well an ample library of historical data gathered
from previous schemes. Carr [13] further emphasized the purpose of a cost estimation
exercise was to provide information for construction decisions. Typical decisions by the
project management team include areas in the procurement and pricing of construction,
establishing contractual amounts for payment, and controlling actual quantities.
Fortune and Cox [20] added that the task of construction cost estimating is a form of strategic
notification that will guide a client when value-for-money business decisions need to be
made. Initial appropriation, economic feasibility study, and resource organization before the
project starts are some pre-contractual groundwork based on such estimates. In an earlier
study by Smith and Mason [34], they have indicated that cost estimating is a fundamental
activity in many engineering and business practices, which normally involves estimation of
the quantity of labour, materials, utility, floor space, sales, overhead, time and other cost
factors for a set series of time period.
Several cost estimation models for different phases of construction development can be
observed in the literature. For example, during the design phase, the probable building cost
can be estimated using cost models based on traditional or non-traditional methods [4,5,10,
19]. Each method has specific conditions that need to be satisfied to produce estimations
exhibiting an acceptable level of accuracy.
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Industrialised Construction
Therefore, this study is in part intended to find out the various cost modelling techniques
practiced by the Malaysian quantity surveyors when they formulate advisories on cost
estimation or forecast. It is postulated that this research will contribute towards the
development of a more robust early-stage cost estimation tool, which in turn would greatly
help construction industry clients make better value-for-money decisions. It also underscores
the imperativeness of the main aim of this study in seeking to develop and bring in a new cost
estimation model for the local IBS-related construction projects. Accordingly, it was
resolved to collect information from the practitioners concerned based on their incidence-inuse (IIU) cost estimation techniques as identified above.
2.
IBS and Cost Modelling
Since the past decade, the pressure to deliver construction projects at a faster pace, lower cost
and higher quality has grown. Clients are now virtually demanding that consultants and
contractors deliver the project in half the time as was used to. On a positive note, this severe
level of expectation has accelerated the prominence and implementation of IBS in the
Malaysian construction industry. Nevertheless, the innovative nature of IBS itself requires a
different set of approach and procedures for it to progress and be substantially attractive to a
wider audience. As a result, the need to accurately estimate the cost of IBS projects has grown
more urgent and important. This is largely because there usually is no feasible time to rescope an IBS project since cost, efficiency and the economies of scale are inseparable
determinants. Clients and construction professionals must be cognizant to the cost
implications of any design, specification or scheduling change throughout the entire project
development process.
2.1
Definitions of IBS
IBS is being acknowledged in many writings as a construction method that has many
advantages especially on aspects of construction management. IBS is defined as “systems that
use industrial production techniques either in the production of components or assembly of
the building, or both” [39]. It is a system where the design and structure of the building are
reduced to a set number of common constituent parts or components, with the rationale that
they can be prefabricated or manufactured in long term production runs, even far away from
the construction site. These components, furnished with standard dimensions and specific
attributes, will then be delivered to the site and assembled according to certain standards in
order to bring together the proposed building.
Reinforced concrete (r.c.) components, whether fashioned on-site or prefabricated at a distant
factory, can be classified as Industrialised Building System [15, 39] products. IBS is deemed
to offer many advantages especially in overcoming problems such as the over-reliance of
unskilled foreign labour, dangerous and dirty construction site, inconsistent work and output
quality, and protraction of construction time. However, the present level of acceptance and
accomplishment of IBS in Malaysia are still very low although numerous incentives are being
offered by the government.
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2.2
Definitions of Cost Modelling
Urry [38] defined model as ‘some representation (usually on paper) that possess some of the
features of the project or system which we are trying to understand and control.’ It can appear
as a table of values, a graph, a network, or a set of mathematical equation. Hence, by
experimenting with the model one can predict to some extent how the real system will
behave.
The definition of cost modelling made by Ferry et al. [19] has the similarity to the above,
namely, ‘…the symbolic representation a system, expressing the content of that system in
terms of the factors which influence its cost.’
Ashworth [4] defined cost models as ‘techniques used for forecasting the estimated cost of a
proposed construction project.’ As a term, it is used when referring both to forecasting
construction cost for clients, and estimating resources cost for contractors.
Meanwhile, Seeley [32] defined cost model as ‘a procedure developed to reflect, by means of
derived processes, adequately acceptable output for an established series of input data.’
Ideally, the model should be simple enough to be applied and understood by the user,
adequately representative of the total range of implications that it may possess, and complex
enough to accurately represent the system. Seeley [32] further added this is because a model
is generally used to evaluate relationships of a whole range of cost variables inherent in a
building design in order to optimize cost forecast, planning and control reliability.
Therefore, all methods, techniques or procedures used by quantity surveyors for cost
estimation or cost forecast may be termed as cost models.
As the construction industry is encouraged to adopt innovation in its trade, it came to the
industry players’ fore to review the prevalent method of cost estimation for cost planning and
control of IBS projects. Drawing from that, and appreciating the need to reform the
construction industry’s practices, it was conceived that reviewing the existent (and
inappropriate) construction cost modelling used in the preparation of cost planning and
control for IBS projects would be most expedient and vital. Its strength should be the ability
to adhere and remain relevant to the ever-changing technology and design dynamics being
manifested from a progressive construction process.
This paper provides an exploratory investigation of the most commonly used cost estimation
methods in the industry, particularly for IBS projects. The following issues were highlighted:
3.
•
Examine the cost estimation model available within the construction industry.
•
Investigate the incidence-in-use (IIU) of cost estimation techniques in the construction
industry.
Types of Cost Estimation Model
The choice of estimation models employed for different phases of construction projects will
be influenced by many factors. Seeley [32] asserted that it would be influenced by the
information and time available, the experience of the quantity surveyor and the amount and
form of cost data on hand. This is parallel to Jrade [24]’s statement that the available
information, time demand, purpose of the estimate, and technique will influence the choice of
cost estimation method to be adopted in a cost estimation exercise.
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Industrialised Construction
Cost estimation models can be at least classified into three main generations [5, 17,22, 31]:
i.
Traditional model.
ii.
Non-traditional model.
iii.
New wave model.
3.1
Traditional Model (empirical model)
These types of model are based on observation, experience and intuition. Physical appearance
of the building and the methods of construction are modelled in terms of description and
dimensions. Bill of quantities is a good example of an empirical model [4]. Empirical models
may use different ways of calculation, e.g. unit method, cubic method, floor area method,
storey enclosure method, approximate quantities method, elementary cost analysis,
comparative estimate, factor estimate, range estimate, parameter estimate, and percentage
estimate [4, 19, 31].
The various methods are simple, easy to understand, and the calculations can be performed
rather quickly. Therefore, practitioners at the management level of the construction industry
are most familiar with this method of modelling, in part because the construction cost can be
clearly presented in the form of units of facility, e.g. cost/bed, cost/seat, cost/pupil [4, 11, 19].
If the right and reliable historical cost data is applied to any of the cost estimation types in the
traditional model then it will be able to generate even better results. However, such practice of
relying on previous occurrences was considered incapable of anticipating the uncertainty and
risks inherent in a building production process [20].
Cost data
Unit/function
(e.g. cost/bed, cost/place)
Cost/sq.m
Space/geometry
Design
stage
Schematic
design
Detailed
design
Constructio
n stage
Operati
ons
it
Elemental
(cost of element-element
quantities)
unit
Approx. quantities
(SMM related)
Detailed quantities
(SMM related)
Commercial
domain
Outline
proposals
Public domain
Feasibility
Feedback
limited
commercial
domain
Activities
(programme related)
to
Resources
(programme related)
Figure 1: RIBA plan of work and its relationship to cost data. (Adapted from Ferry et al. [19])
Figure one, based on the RIBA plan of work and adapted from Ferry et al. [19], shows some
of the more traditional models developed over the years to suit the various stages of a design
process. The pyramidal diagram is an attempt to show that as we descend the list more
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
detailed cost estimates are required to suit the structure of the model. It also shows the nature
of input employed in the Design stage model corresponding to the different categories of data
in the Cost data model.
3.2
a)
Non-Traditional Model
Regression Model.
Regression, or multiple regressions as it is usually called, is a technique of determining a
formula or mathematical model that best describes the data [4, 17, 28]. Approaches to cost
estimation based on statistics and linear regression analyses have been developed since the
1970s [26]. The output (or dependent variable) may be expressed in terms of a single or set
of independent variables. Thus, the relationships may be called a linear or multi-linear
regression model. However, non-linear regression models also exist, e.g. in the forms of
polynomial, exponential, logarithmic and power functions [17, 25, 35].
Stockton and Middle [36] observed the advantages of using the regression technique to
develop an estimation model, saying if the model is assumed correct, it yields an unbiased and
efficient estimate of the model’s parameters with which to predict the value of the dependent
variable given the value of independent variables.
Multiple regression analysis can be generally represented in the form of:
Y = C + b1 X1 + b2 X2 +……. bi Xi,
(1)
Where Y is the total estimated cost, and X1, X2,….Xi are measures of distinguishable
variables that may help in estimating Y. For example, X1 could be a measure for the gross
floor area, X2 the number of storey, etc., C is the estimated constant, and b1, b2,…bi are the
availability of some relevant data. The Statistical Package for Social Science (SPSS)
software’s stepwise technique is normally used to develop the regression model.
b)
Probabilistic or Simulation Model
Simulation means imitation. It is not real but only pretending to be real. A simulation model
duplicates the behaviour of the system under investigation, i.e. by carefully collecting data
over a long period of time and studying the interaction among the components. Probabilistic
or simulation models allow the user much flexibility in representing complex systems that are
normally difficult to analyze if using standard mathematical models. However, developing the
model may be a very costly and time-consuming procedure, let alone optimizing it [4].
Probabilistic or simulation modelling started with a popular method called Monte Carlo
Simulation Technique. The modelling can be used for determining the proper unit rate and
productivity [5, 31], to predict the life expectancy of building components in a life-cycle cost
calculation [5], to estimate the probability of budget overruns [37], to predict the amount of
contingency fund and can also be used in fields like tender bidding and cost forecasting which
are indeterminate in practice [5, 31].
However, probabilistic models have some
disadvantages such that the distribution of the occurrences or variables must be known or
predetermined in order for the probability to be assigned to the experiments or events [32].
71
Industrialised Construction
3.3
a)
New Wave Model
Artificial Intelligence (AI)
Developments in information and communication technology have also facilitated some novel
approaches for cost estimation, i.e. inspiring ideas that hitherto were virtually unheard of
within the construction industry. Fortune and Cox [20] have identified in their study that other
than the previously mentioned cost model generations, there are techniques that they
classified as ‘new wave’ models that could be put into practice. One such type of model
available to practitioners was based on the research and development of AI tools such as
neural networks and fuzzy logic. As a result of the emergence of the AI tools, possible multiand non-linear relationships can now be investigated.
The Artificial Neural Networks (ANN) is a computer system that simulates the learning
process of the human brain. Like the human brain, neural networks learn from experience,
generalize from previous examples to new ones, and abstract essential characteristics from
inputs that contain irrelevant data. Network components with names such as neurons
(sometime referred as cell, units or nodes) and synaptic transmissions with weight factors are
used to mimic the nervous system (analogous to synaptic connections in the nervous system)
in a way that allow signals to travel through the networks in a parallel pattern, as well as
serially. Although neural networks have some qualities in common with the human brain, this
resemblance is only superficial.
The applicability of the ANN types of cost estimation model has been extensively studied [8,
9, 14,18, 23, 26, 27, 30] and widely applied in many industrial areas, including construction.
Researchers have explored the application of ANNs to improve the accuracy of cost
estimating beyond that of the regression model [1, 7, 29, 33].
b)
Web-Based Tools
Coyle [16], and Jrade [24] reported the use of web-based tools as being evident in
construction projects. Coyle[16]’s work identified new opportunities such as using the
AutoCAD computer program’s 3D-modelling tool to integrate the design and simulation of
construction costs, as well as develop a parametric approach to expedite a new forecast
generation. In the same way, Jrade [24]’s work identified the same tools that integrate the
conceptual cost estimating and life-cycle costing systems for building projects.
c)
Other Tools
Other types of cost estimation models can be found in the report by Bartlett and Howard [6],
including tools such as the BRE Invest technique that was asserted as being available in the
UK. The tools were catered for environmentally and sustainable development types of
construction practices.
4.
Objectives and Methodology of Study
The main objective of the study is to identify the most widespread or preferred incidence-inuse (IIU) cost estimation model being employed by the Malaysian quantity surveyors,
especially for projects using IBS. The study adopted a self-administered, six-page postal
questionnaire survey accompanied by a covering letter. The letter customarily explained the
objectives of the research and made an important request for the respondent to indicate what
type of cost estimation model he or she employed when preparing a cost estimate particularly
at the pre-tender stage. The questionnaires were sent to all quantity surveying firms registered
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
with the Board of Quantity Surveying Malaysia (BQSM), the professional body that governs
the quantity surveyors in the country.
A case in point, the questionnaire design was based on a combination of past comparable
surveys discerned after an extensive review of the literature that dealt mainly on cost
estimating, and was piloted with several quantity surveyors from four different consulting
firms. Forty-one (15%) firms from a total of 278 responded to the survey. The data were then
computed and analysed descriptively using the SPSS statistical program.
5.
Analysis of Data
5.1
Demographic Profile of the Respondents
Based on the forty-one responses received, thirty-one answered the questionnaire pertaining
to their experiences in the construction industry and the organization.
The respondents who participated in the survey are all engaged in the runnings and
implementation of building construction, civil engineering work, as well as mechanical and
electrical engineering works (construction). Table 1, Table 2 and Table 3 respectively show
the distribution profiles of their experience in the construction industry, the organization and
academic qualification, as well as the organization’s nature of business.
Table 1:
Frequency Distribution of Respondents’ Working Experience in the Construction Industry.
Range of working
experience (Years)
No. of
Percentage
respondents
(%)
1-10
11
28.2
28.2
11-20
12
30.8
59.0
21-30
14
35.9
94.9
31-40
2
5.1
100.0
Total
39
100.0
Table 2:
Cumulative percentage
(%)
Frequency Distribution of Respondents’ Working Experience in the Organization.
Range of working
experience (Years)
No. of
Percentage
respondents
(%)
1-10
24
61.5
61.5
11-20
6
15.4
76.9
21-30
9
23.1
100.0
Total
39
100.0
73
Cumulative percentage
(%)
Industrialised Construction
Table 3:
Frequency Distribution of Respondents’ Academic Qualification
Academic
Qualification
No. of
Percentage
respondents
(%)
Diploma
1
5.4
5.4
Degree
31
64.0
69.4
Master
8
23.4
92.8
Total
40
100.0
Table 4:
Cumulative percentage
(%)
Frequency Distribution of Respondents’ Designation in the Organization
Level of position
No. of respondents
Percentage
(%)
Cumulative
percentage (%)
Top Management
16
52.7
52.7
Middle Management
8
23.2
75.9
Professional/Technical
16
24.1
100.0
Total
40
100.0
Table 1 and Table 2 show the distribution of the respondents’ working experience in the
construction industry and the current organization respectively. It can be concluded that the
majority of respondents have between 10 to 30 years of working experience in the
construction industry.
On the other hand, the respondents’ working experience in the organization ranges from 1
year to 10 years only. Moreover, the respondents’ academic qualifications shown in Table 3
verified that a majority of the respondents possess a high level of academic qualification.
Thirty-one respondents (64%) were Degree holders, eight respondents (23.4%) were Master
degree holders and the remainder (5.4%) were Diploma holders. This indicates that a majority
of the respondents have creditable experience in the construction industry and backed with the
appropriate qualifications, consequently making them eligible respondents to the survey.
The data analysis also examined the company’s core or nature of business. This was to ensure
that the respondents have direct and equitable involvement in the construction industry. The
results indicate that a majority of the respondents are practicing quantity surveyors while only
a few are project managers.
Table 4 shows the distribution of designation or post held in the company. Percentage-wise, it
can be concluded that the survey managed to cover a spectrum of high-ranking personnel in
which a majority either belong to the Top Management level, such as director, principal,
managing director, etc., or the Professional/Technical level. Therefore, the information
provided by the respondents regarding the significance of choice of type of cost estimation
model can be considered as highly reliable and authoritative.
5.2
Currently-used Cost Estimation Model
The objective of this section is to establish the prevailing pre-tender stage cost estimation
modelling used by the Malaysian quantity surveyors, especially in building construction
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
projects using IBS. Quantity surveyors were selected as the survey’s target group because
they received formal training especially in the planning, design, and conceivably the
construction stage of a project as well. They are continually involved in works and studies
that require thorough understanding of the principles of building and engineering economics.
Most of the data were designed as nominal or ordinal in nature so as to facilitate easy
response and statistical analysis. Accordingly, respondents were also asked to indicate which
type of model they most frequently use. The instrument used in the questionnaire for
measuring IIUs of estimation techniques are the ascending Likert scaling procedure where (1)
indicates ‘Never’; (2) indicates ‘Seldom’; (3) indicates ‘Often’; (4) indicates ‘Frequently’; and
(5) indicates ‘Always’. These scaling procedures were also used to rate the percentage
distribution of the IIUs from each of the model. The set ratings are 0% IIU for ‘Never’; 1%33% IIU for ‘Seldom’; 34%-66% IIU for ‘Often’; 67%-99% IIU for ‘Frequently’; and 100%
IIU for ‘Always’.
Table 5:
Incidence-in-use (IIU) of Traditional Types of Cost Estimation Model
Modelling
Average Point
Average Incidence-inuse (IIU), N= 41
Rank
Conference
2.2
1% - 33%
8
Financial method
2.9
1% - 33%
6
Functional unit
3.0
34%-66%
5
Superficial
3.9
34%-66%
2
Superficial-perimeter
2.2
1% - 33%
7
Cube
1.8
0%
10
Storey-enclosure
2.1
1% - 33%
9
Approximate quantities
4.0
67%-99%
1
Elemental estimating
3.7
34%-66%
4
Bill of quantities
3.9
34%-66%
3
Table 6:
Incidence-in-use (IIU) of Newer Non-Traditional Types of Cost Estimation Model
Modelling
Average Point
Average Incidence-inuse (IIU), N=41
Rank
Regression analysis
1.5
0%
4
Causal model
1.5
0%
5
1.3
0%
6
Value management
2.4
1% - 33%
1
Knowledge-based
model
1.3
0%
7
Resource-based model
2.0
1% - 33%
2
Life-cycle model
1.7
0%
3
Monte
simulation
Carlo
75
Industrialised Construction
Table 7:
Incidence-in-use (IIU) of New Wave Types of Cost Estimation Model
Modelling
Average Point
Average Incidence-inuse (IIU), N=41
Rank
Neural network
1.2
0%
2
Fuzzy logic
1.2
0%
3
1.6
0%
1
Environmentally
Sustainable
development
&
The status of cost estimation types under the newer non-traditional and new wave models can
be seen in Table 6 and Table 7 respectively. Evidently, the Value management type (1%33%) and Resource-based type (1%-33%) were seldom used. The survey also revealed that
the newer non-traditional cost estimation models that have been developed by the academe
over the last 30 years continue to draw very limited attention. Furthermore, some of the leastused methods besides those from the newer non-traditional model belong to the new wave
model. In particular, the Environmentally & Sustainable development type (0%), the Fuzzy
logic type (0 %) and Neural network type (0%) have to date made insignificant, or naught,
impact.
The above findings indicate that the traditional types of model were, in general, still the most
widely used. Of the newer non-traditional and new wave models, only the Life-cycle cost and
Value management types show any evidence of being in general use. Previous works by
Fortune and Hinks [23], and Fortune and Cox [24] provided similar results. Fortune and Cox
[24]’s study was conducted in the UK and used only large-sized organizations that described
themselves as an amalgam of quantity surveying, project management or multi-disciplinary
types of organization. It can be surmised that the continued and overwhelming use of the
traditional types of model at the expense of the newer non-traditional types have somewhat
stigmatised Brandon [14]’s call for a paradigm change towards a more innovative and
dynamic model. As a result, the study has indicated that Brandon[14]’s praiseworthy beckoning
also is still being largely ignored by the Malaysian practitioners concerned.
Various reasons can be inferred as to why the local quantity surveyors are not using the nontraditional or new wave cost estimation models although vouched by the academe as being the
more superior counterpart. Some of the reasons can be attributed to: (a) lack of familiarity
with the newer techniques; (b) the degree of sophistication is seen as too superfluous for an
average project; (c) time constrain, plus lack of information and knowledge; (d) doubts
whether these techniques are replicable to other projects; (e) most construction projects are
not large enough to warrant the use of these techniques or research into them; (f) they require
the availability of sound data to ensure confidence; and (g) the vast majority of risks are
contractual or construction-related, and are fairly subjective such that they can be dealt with
better on the basis of personal experience or from previous contracts undertaken by the
company [3, 22, 23, 24].
6.
Conclusion
The findings of the study revealed that the traditional type of cost estimation models continue
to be in widespread use irrespective of organizational size and type. Value management and
resource-based types were also found to be in use, although not as numerous. Newly
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
developed types of cost estimation model such as artificial neural network, fuzzy logic, as
well as environmentally and sustainable development types were seen, as yet, to have almost
negligible application in practice. The continued and overwhelming use of the traditional
types of model suggest that the call by Brandon[14] for a paradigm change since some 26 years
ago is still being overlooked.
This phenomenon is comparable to findings from other similar researches conducted in
countries like the UK, Hong Kong, Australia and Nigeria. An appraisal or review of the cost
estimation practices in construction projects is essential particularly of those using IBS. This
is vital in order for IBS to be well placed, and accordingly evolve with the various
innovations that transpire within the construction industry. If need be, the appraisal must also
be re-strategised to take advantage of the various benefits presented by the newer nontraditional and new wave cost estimation models in cost planning and control practices.
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35. Sonmez, R. (2004) Conceptual Cost Estimation of Building Projects with Regression
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80
The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Evolutionary Modeling as a Mean of Mass-Customization for
Industrialized Building Systems -Two Cases ExploredHicham Zakaria
Groupe de Recherche en Conception Assistée par Ordinateur (GRCAO)
University of Montreal, Montreal, Canada.
Abstract
Traditional modes of production, in the construction field, are no more able to deliver quality buildings for all people.
Actually, industrialized building systems are indeed reducing the cost of buildings in a significant way and promises to make
quality more available. Everyone is however different from the other and from himself -trough time-. His needs often do the
same so the likeness feature of industrialized building products did rarely satisfy all individualities. This research project
aims to examine how evolutionary modeling could help manufacturers of building systems to introduce Mass-Customization
within their Mass-Production lines and also help clients to adapt their buildings for new needs. Two cases of building systems
are explored within a new modeling environment: the first focuses on building component’s shape flexibility while the
second case explores the combination among these components. Experiments are discussed at the end of the paper and,
perspectives are drawn for next developments.
Keywords
Building systems; Evolutionary modeling; Industrialization; Mass customization
1
Introduction
After many decades of existence, there is no doubt that industrialized building systems
weren't able to alter the long-established methods of architectural production. Some architects
argue, however, that the profession needs "a new vision of process, not just product… The
world, and our clients, have seen what has been accomplished in other manufacturing fields:
ships, airplanes, and cars. Higher quality and added scope and features are there, along with
lower cost and shorter time to fabricate" [6], which supposes that the actual market
conditions urge the building field to meet what is already done in other industries.
For a long time, building construction was interested in industrial processes especially for
developing new building systems. As early as in 1914, Charles-Édouard Jeanneret (Le
Corbusier) designed the domino system, which is a set of structural components, easily
combinable, to help rebuilding ruined constructions in the Flandres region. Later on, building
systems have been given an increasing importance especially in 1950th and 1960th when
reconstruction, housing, and social equipments were top governments' priorities [5].
Many building projects with more or less success followed this period and building systems
became a particular branch of the architectural field, having at least two main ends:
prefabricating in plant as many components as possible and, bringing adequate managing
methods for using these products in design and building process. For this second aspect,
computer techniques and particularly evolutionary modeling, which is an extension of
generative modeling that involves genetic algorithms to explore shape generation
possibilities, can play an interesting role in the cognitive process of design [10].
This article explores two cases of building systems and discusses how evolutionary modeling
could help manufacturers of the building systems to introduce Mass-Customization within
their Mass-Production lines, and also help clients to adapt their buildings for new needs. For
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Industrialised Construction
this, let's examine, in the following chapter, the design situations in which building systems
may be used, and then make a selection of the building systems that will be modeled. Further,
a selection is made among building systems to choose those that will be modeled in our
evolutionary modeling system.
2
Design Situations
It seems by now fairly accepted that prefabrication solutions satisfy a large number of
building shapes. When making components for a new architectural project, prefabricated
solutions are used in almost three situations [9].
(i) The project's design is realized by the producer, of the components himself, often
responsible of erection of the building too. In this situation the producer may adapt a set of
pre-existing modules he already produces for economical performance but, very often the
design of components is uniformly optimized for a particular kind of buildings which may be
considered as a closed system, in a sense that the adaptability of the design for new
architectural requirements becomes very limited;
(ii) In the opposite side of the fence, a different situation happens when an architectural
design or requirements focus exclusively on the client needs without initial regards to how the
building's erection may take advantage of the industrialized alternatives and solutions which
could avoid reinventing the wheel for each new project. In this tricky situation, a precaster has
to reconsider his own prefabrication methods and try to design components suited for the new
project design ;
(iii) A more remarkable situation occurs when effective coordination levels, often modular or
dimensional, are established between the project partners particularly at the first stages of
design process. Up to a certain point this situation is comparable to a design-build approach,
but in respect to abilities of both architects (for developing innovative expressions and use of
our living environment) and producers (for making high quality components accessible at low
prices).
Despite an undeniable potential in such a kind of partnership, innovation and standardization
were considered for a long time as contradictory concepts in the field of architecture. To
demonstrate that this is not completely true, some analogies was drawn in the past between
architecture and music which is another kind of artistic production and usually uses a same
short set of predefined notes [6], but it is more accurate to compare music notes to bricks, as
elementary parts, than to composite building blocks.
Actually, almost all erected buildings in the industrialized world are made from at least some
industrialized materials, making the emblematic antagonism between traditional and
industrialized mode of production outdated. Instead of this, different levels of
industrialization may be distinguished in the building construction [3]. In this sense, the
literature about building construction reveals five degrees of industrialization: prefabrication,
mechanization, automation, robotics and reproduction [7], making the strategies for
developing and employing building systems, greatly sophisticated.
A major challenge of the industrialization of building systems relates no doubt to the use of
these systems in the design of new and innovative architectural arrangements. Many architects
and designers are reticent about the use of these systems in new projects, since they are often
considered as reducing the artistic expression. The components' shape geometric flexibility
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
and their combination possibilities and interchangeability are, however, interesting
approaches for exploring new architectural arrangements.
3
Building System as a Framework
As evoked previously, an industrialized building system has two aspects: (i) a physical aspect
regrouping a set of standardized parts that determine the building shape and its technical
performance; (ii) and a set of rules and methods used for assembling and combining the
different parts. From a geometrical viewpoint, a building system may use three arrangements:
(i) linear arrangement, which is the case of beams and columns; (ii) planar assembly, which is
the case for slabs and panels; (iii) and three-dimensional assembly, which often uses box
units.
An industrialized building system also contribute to an organization of work between the
factory, where components are prefabricated, and the work-site, where the building is erected
using these prefabricated components. From this viewpoint, industrialized building systems
fall into three categories including the previous geometrical classification: (i) the kit of parts
meaning that all subsystems are fabricated in the factory, and brought in pieces to the worksite. These parts include posts, beams, slabs, columns, panels or components with integrated
joints; (ii) the factory-made modules means that all the building spaces and elements are
made, assembled and finished in the factory -these 3D modules are brought to the work-site
and connected directly to foundations-; (iii) some hybrid systems stands between the previous
two categories, in a sense that as much as possible sophisticated elements are prefabricated in
plant, but when module's transportation become complicated the system is reassembled in situ
[7].
Two industrialized building systems were chosen for our modeling experiments: the Triedro
system, a site-assembled kit of parts which uses integrated joint concrete trihedron modules
and, the Sekisui system, a factory made 3D module using edge frame members. Three reasons
stay behind this choice : (i) for the Triedro system the modules' connection positions and the
geometrical intersection do not match because of the integrated joint, meanwhile in the
Sekisui system, they are precisely the same, which makes Triedro more appropriate to explore
combination and interchangeability strategies and Sekisui units appropriate to explore the
shape flexibility strategies; (ii) both of the two building systems use a set of interchangeable
building components which allows a modular coordination in the design process for buildings
that use these systems; (iii) both systems use 3D modules that not only enclose served or
serving spaces, but also have a load-bearing structural role, in a sense that the modules of
each system are directly connected vertically without need of an extra structural framework.
Implementation of these functional and structural features on a 3D modeler allows dealing
with architectural cells –space units used in a design process–, instead of elementary
components like walls, beams or slabs, used in most architectural software.
4
Materials and Methods
Originally, the box shaped modules of both Triedro and Sekisui systems inspired the use of
matrix patterns to place individual space of a given architectural program. It was somehow
similar to the GENCAD [4] approach: this modeling system also uses a matrix structure to
arrange architectural spaces. For example, given an architectural specification program, each
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Industrialised Construction
space of this program is coded by an individual number. This list of number is then traversed
sequentially and every number is randomly put in an empty matrix cell.
This random approach for placing spaces is no doubt interesting because it allows generating
different spaces' arrangements. The matrix structure is, however, more appropriate for
examining dimensionless configurations from a speculative viewpoint in particular. In this
sense, building considerations were never taken into account. This approach was also
restrictive in a sense that the generated arrangements could neither reconcile all geometrical
dimensions and proximities among spaces nor allow the exploration of building
configurations that do not fit into exact rectangular shapes.
One of the main characteristics of building systems –in comparison to traditional building
production methods- is that all technical details are resolved in advance in the factory, before
that the building erection starts. Thus, it was interesting to develop a new modeling approach
that considers both the geometrical constraints and the modular joining of the building
systems as it generates architectural arrangements. Among the many possible ways to model
the elements of a building system and its composing rules, the procedural model [8] was more
convenient for establishing a generative approach: a procedural model regroups a set of
programming functions that model the geometrical operations required to compose a given
architectural object. A procedural model also allows transforming the corresponding
architectural object according to some its relevant parameters.
The implementation of procedural models for the building system modules was realized using
the parametric modeling environment Synan. Two particular features of this environment
were used for this: its solid modeler and its embedded scripting functional language: Scheme.
To illustrate how a compositional process may be translated into procedures, we present
below the function (triedro_mdl_07) that generates one of the Triedro building
modules (Fig. 1).
(define triedro_mdl_07
(lambda ()
(append (append
(triedro_sb_00)
(move (triedro_wl_01) 0.0
(- TRD_WIDTH TRD_WL_THIKNESS)
TRD_SB_THIKNESS))
(move (rotate (triedro_wl_00)
0.0 0.0 -90.0)
0.0 TRD_WIDTH TRD_SB_THIKNESS)
)))
Fig. 2. Example of a scheme function that generates a Triedro module.
A procedural model is also a hierarchical structure that may incorporate other sub-functions,
like (triedro_sb_00) in the above case: this later function generates the module's slab. Hence,
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
the scripting approach allows progressive improving of the model, by altering its parameters
or incorporating more accurate definitions [1], unlike the interactive modeling CAD
techniques which focuses on a specific geometrical model.
5
Experimenting the Evolutionary Model
In a building system, each module usually has a number of connections that articulate it with
other modules of the building. To elaborate an evolutionary modeling approach we are
interested in the positioning of theses nodes. The analysis of Triedro and Sekisui building
systems allows elaborating algorithms that identify potential connecting nodes for each
module. For example, Triedro modules accept up to five extension nodes (Fig.2 -A), while the
positioning of a Sekisui extension node depends on the subdivision of its module's dimensions
by the normalized lengths and widths available in this building system (Fig.2 -B).
When a given extension node is selected, it becomes possible to insert a new module at this
connection position. A recursive function allows finding the extension nodes for the new
module using the same process.
(A)
(B)
1,350
2,475
2,925
3,375
N1
N2
N3
3,825
N1
N2
4,275
4,725
5,175
N4
5,650
N5
Fig. 3. Deployment of nodes in a Triedro module (A) and a Sekisui module (B).
While procedural models allow the definition of a shape grammar of a building system, an
evolutionary approach may be considered as modeling the progressive transformation of a
procedural model itself [10]. This study examined two kinds of transformations (Fig.3): a
random transformation for the case of Triedro system and, an oriented transformation for the
case of Sekisui. Genetic codification was used in both cases, but fitness function only of the
second.
In Triedro case, we used a predefined plan composed of six modules. This plan was codified
with a string of six integers 0 to 5 that represents its genome, for example: 1-5-2-0-3-2. Each
digit corresponds to a particular module in the Triedro shape grammar. A genetic algorithm
allows to change randomly the values of these digits and a procedural model generates the 3D
model corresponding for each randomly configured genome (Fig.3 -A).
For the Sekisui case, we used a predefined set of dimensionless plans, composed by four
modules each. These plans were codified with a string of nine numbers: the first one
corresponds to the type of the plan, while the eight others correspond to lengths and widths of
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Industrialised Construction
its modules. Each of these eight last numbers was randomly fed with one of the Sekisui
normalized dimensions. The fitness function of the genetic algorithm determines genomes
that match the dimensions of all four modules (Fig.3 -B).
(A)
(B)
Fig. 4. Examples of generated compositions for Triedro (A) and Sekisui (B) systems.
6
Conclusion
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It is obvious that the potential of industrialization of building construction was realized in a
very limited way. In fact, a resilient unwillingness towards standardization is prevailing
among a large number of building professionals. Reasons behind this situation range from
aesthetic restrictions to the high investments needed to adapt actual education culture and
production resources of the building field [9].
The evolutionary model we developed in this research has proved effectiveness in generating
3D models according to the rules of the two explored cases of industrialized building systems.
It has also demonstrated that shape flexibility and combination may be effective strategies to
explore architectural compositions using these building systems.
The experiments we made allow us to develop a method for integrating industrialized
building systems, especially prefabricated solutions, early in the architectural design process.
The implementation of this method on a digital environment may help the development of
dynamic communication mean between producers and designers.
It is important to note, however, that the development of such methods is far from substituting
the expertise of a professional designer whose feeling and rational remain the keys for
innovative solutions. Its objective was just to help user to explore customization possibilities
of architectural compositions realized according to some industrialized building system.
References
1. Charbonneau, Nathalie: Understanding Gothic Rose Windows with Computer Aided
Technologies. In Vassilis Bourdakis and Dimitris Charitos (eds.): Education and Research
in Computer Aided Architectural Design in Europe : Comunicating Space(s), eCAADe
Volos (2006) 770-777.
2. Dainty, Andrew, Moor, David, Murray, Michael: Communication In Construction: Theory
And Practice. Taylor & Francis London (2006).
3. Davidson, Collin H., Richard, Roger-Bruno: Re-engineering Construction – Is It Something
New?. In George, Ofori, Florence, Yean Yng Lin (eds.): Knowledge Construction,
proceedings of the Joint International Symposium of CIB Working Commissions
Singapour (2003) 297-309.
4. De Silva Garza, A. G., Maher, M. L. Using Evolutionary Methods For Design Case
Adaptation. In J. Wassim (eds.): Reinventing The Discourse, proceedings of ACADIA
2001. New York: Association for computer-aided design in architecture, (2001) 180-191.
5. Ehrenkrantz, Ezra D.: Architectural systems. McGraw-Hill Montreal (1989).
6. Kieran, Stephen, Timberlake, James: Refabricating Architecture: How Manufacturing
Methodologies Are Poised To Transform Building Construction. McGraw Hill New York
(2004).
7. Richard, Roger-Bruno: Reproduction Before Automation And Robotics. In: Automation in
Construction Journal, Elsevier Amsterdam (2004) 442-451.
8. Tidafi, Temy, Iordanova, Ivanka: Vers Un Environnement Informatique Favorisant la
Conception Assistée par Ordinateur. In: Giovanni, De Paoli, Temy, Tidafi (eds.):
Modélisation Architecturale et Outils Informatiques entre Cultures de la Représentation et
du Savoir-Faire, ACFAS Montreal (2000) 17-36.
9. Warszawski, Abraham: Industrialized And Automated Building Systems. E&FN Spon
(1999).
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10. Zakaria, Hicham: Proposal For a New Approach For Simulating Transformations of a
Built Environment – case of Saint-Laurent shop fronts in Montreal. In Giovanni, De Paoli,
Khaldoun, Zreik, Reza, Beheshti (eds.): Europia11 Paris (2007) 57-68.
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Energy-usage and CO2 Emission: How Unfired Clay Based
Building Materials Development in the UK Can Contribute
Jonathan E Oti1*, John K Kinuthia1, Jiping Bai1
1
Department of Engineering, Faculty of Advanced Technology, University of Glamorgan, Trefforest,
Pontypridd, Rhondda Cynon Taff, South Wales, United Kingdom, CF37 1DL.
{joti, jmkinuth, jbai}@glam.ac.uk
Abstract
This paper reports on energy usage and carbon dioxide (co2) reduction technology. It presents the results of laboratory tests
on lime-stabilised Lower Oxford Clay (LOC) using different levels of lime, and Portland cement (PC), and using these
traditional stabilisers blended with Ground Granulated Blast-furnace Slag – GGBS. LOC is the clay used by Hanson Brick
Company Ltd. to make fired, “London” bricks at their Stewartby brick plant in Bedfordshire. The research looks into Lime
(L)-PC, L-GGBS and PC-GGBS blends to assess their potential for application in sustainable unfired clay building materials
(bricks, mortar etc.) in the United Kingdom (UK). Unfired materials will not only reduce energy costs, but also the
environmental damage associated with the present traditional firing process of manufacturing clay building components.
Due to the high strength requirement in the building industry compared with stabilized highway pavement layers for
example, a high maximum stabilizer dosage of 20% was used. For road construction, typical dosage ranges from 3-8% for
lime and 3-5% for PC. In the current investigation, cylindrical specimens were cured for 28 days at moisture contents of
25%, 30%, 35% and 40%, before testing for unconfined compressive strength.
Preliminary results show that the strength values for all stabilised materials investigated was within the strength range of
737kN/m2 to 2077kN/m2 at 28 days, with the L – PC blends tending to have lower strength values when compared with the L
– GGBS blends. These results suggest that there is potential to use the blended binders for the manufacture of unfired
building materials.
Keywords
Compressive strength; Unfired-bricks; Fired clay; Lime; Portland cement; Stabilization;
Carbon dioxide.
1
Sustainability; Slag; Energy;
Introduction
The energy used in the production of building materials accounts for over 75% of the total
embodied energy in buildings [1], and thus improvements of energy use in production
processes is a crucial part of any overall strategy for energy conservation in the built
environment. Much of the energy used in building materials takes place in the manufacture of
a few extensively used materials which involve high temperature kiln processes, notably clay
bricks, cement, tiles and glass. Therefore energy saving techniques concentrating on unfired
clay building material development incorporating low-energy additives will benefit both the
present and future generation.
The main benefit of unfired clay building products is the reduction in manufacturing energy
cost which translates to a reduction in CO2 production. Other added advantages of this
technology is that it has a low embodied energy content and outstanding natural building
breathing properties like absorption and diffusion of water vapour and heat. These benefits are
inherent in the manufacture process, but also continue through the whole product life cycle.
The new clay based materials formulated by stabilising clay soil with various blends of lime
GGBS with or without PC is particularly appropriate in the restoration of historic buildings
and internal/external partition wall construction. However, the strength and durability
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Industrialised Construction
requirements currently achievable using PC alone, and/or those demanded by the building
industry can be attained by using significant amounts of the less expensive GGBS (relative to
PC). It is interesting to note that GGBS is a by-product of the steel manufacturing processs.
The added advantage of not using PC alone ensures the formulations compete favourably in
the market place.
Firing clay building products in kilns with large amounts of energy consumption introduces
energy-related costs to the end products. Recent increases in gas prices will further excerbate
this cost element. This high cost is currently being transfered to the consumer, thus indirectly
affecting the global economy. The current method of manufacturing clay-based building
materials involves intensive heating of the soil to a temperature of around 1000oC before
effective strength as requred by the building industry is attained. This intensive energy usage
causes environmental damage. An estimated 8-20% of global carbon dioxide emissions in
different countries arising due to construction and building materials production activities
with a further 2.5% global carbon dioxide emission results from the firing clay building
material production and that of PC manufacture[1]. There is therefore, an opportunity to lower
the cost of bricks by saving on energy consumption and costs in the manufacturing of the
stabiliser with the use of GGBS with or without traditional binder (PC) to stabilise soil for
unfired building material production.
Research work by Wild et al. [2] has been successful in stabilizing clay soil using lime to
activate GGBS. The first application of GGBS-based formulations in road pavement
construction in the UK was on the A421 Tingewick Bypass in Buckinghamshire. Previous
research [3] on steam-cured soil blocks for masonry construction explored only the curing
process of lime stabilisation, thus the research was only able to achieve 35% reduction in
energy consumption of the clay firing process. Research [4] on the development of unfired
clay building material used only a semi-processed industrial kaolinite clay soil; these
formulations are still awaiting full industrial trial. Research using GGBS systems [5] was
successful at laboratory scale for stabilised concrete bricks. Planning Factsheet [6] revealed a
promising development on the potential for utilising GGBS in the manufacturing of extruded
bricks where GGBS can replace up to 20% of the clay content, thereby reducing the firing
temperature of the clay, hence reducing energy costs.
Research of literature demonstrates little or no reported studies on unfired clay technology for
building components such as bricks, blocks and mortar in the UK. Hence, this research is
anticipated to contribute to the knowledge on new building materials which is energyefficient, economical in meeting the needs of society, and provide technical solutions that will
enable the brick industry to develop commercially viable products from unfired clay. This
will produce materials which are more sustainable, cheaper and technically responsive
compared to existing products. The study will examine clay soil stabilised with various
blended mixtures of lime, PC with GGBS and assess their potential application for the
manufacturing of unfired clay building materials in the UK, this will help to reduce energy
usage and the high CO2 emission associated with the conventional method of manufacturing
clay building products.
2
Methodology
2.1 Material
Materials used in this research consist of Lower Oxford Clay (LOC), lime, GGBS and PC.
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
2.1.1 Lower Oxford Clay (LOC) The LOC used in this study was supplied by
Hanson
Brick Company Ltd, Stewartby brick plant in Bedfordshire UK. The LOC contains 23% illite,
10% kaolinite, 7% chlorite, 10% calcite, 29% quartz, 2% gypsum, 4% pyrite, 8% feldspar and
7% organic materials. This clay material is currently being used by Hanson Brick Company
Ltd to make fired “London” brick, it is therefore an excellent choice of clay material and the
most practical endeavour for the unfired clay building material development. The chemical
and physical properties of the LOC are shown in Table 1.
2.1.2 Lime (L). The lime used in this study was quicklime (CaO) supplied by Buxton Lime
Industries Ltd, Buxton, Derbyshire, UK. The chemical and physical properties of the lime are
also shown in Table 1. The reason for using quicklime rather than hydrated lime as the choice
of binder was because quicklime has been used successfully for practical application of lime
columns for the improvement of slope stability [7].
2.1.3 Ground granulated blast furnace slag (GGBS). The GGBS used in this
investigation was supplied by Civil and Marine Slag Cement Ltd, Llanwern, Newport, UK.
The chemical and physical properties of the GGBS are also shown in Table 1.
2.1.4 Portland cement (PC). Cement manufactured in accordance with the British Standard
BS EN 197-1 [8] was supplied by Lafarge Cement UK. Table 1 also shows its chemical and
physical properties.
Table 1: Chemical and physical properties of Lower oxford clay, quicklime, GGBS and PC (data provided by Hanson Brick Company Ltd,
Buxton Lime Industries Ltd, Civil and Marine Ltd and Lafarge cement UK respectively)
Composition (%)
Oxide
GGBS
PC
CaO
Lower Oxford clay
6.15
Quicklime
95.9
41.99
63
SiO2
46.73
0.9
35.35
20
Al2O3
18.51
0.15
11.59
6
MgO
1.13
0.46
8.04
4.21
Fe2O3
6.21
0.07
0.35
3
MnO
0.07
−
0.45
0.03 - 1.11
S2
−
−
1.18
−
SO3
−
−
0.23
2.3
CaCO3
−
2.2
−
−
TiO2
1.13
−
−
−
K2O
4.06
−
−
−
FeO
0.8
−
−
−
P2O5
0.17
−
−
−
Na2O
0.52
−
−
−
Loss on ignition (LOI)
15.75
−
−
−
Insoluble residue
−
−
0.3
0.5
Relative density
−
−
2.9
3.15
Bulk density (kg/m³)
−
480
1200
1400
grey
white
Off - White
Grey
−
−
≈ 90
−
Colour
Glass content
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Industrialised Construction
2.2 Sample preparation, mix composition and testing
In order to identify the relative effect of the L-PC, L-GGBS and PC-GGBS combinations on
the LOC, mixes were made by varying the relative proportion of lime to PC, lime to GGBS
and PC to GGBS but maintaining an overall maximum total binder content of 20 wt%. The
unblended lime, PC and GGBS were used as controls.
For the purpose of sample preparation it was found necessary to establish target dry density
and moisture content values. Therefore, Proctor Compaction tests were carried out in
accordance to British standard BS 1924-2: 19 [9] in order to establish values of the maximum
dry density (MDD) and optimum moisture (OMC) for the unstabilized LOC. The MDD and
OMC values were established as 1.42Mg/m³ and 29% respectively. The approximate range of
moisture content over which 90% MDD (1.28 Mg/m³) can be achieved was from 22% to 40
%.
In practice due to evaporation, hydration and cracking/expansion the tendency is to compact
on the wet side of the OMC (25% - 40%). For this investigation 25%, 30%, 35% and 40%
moisture contents were used in the LOC–GGBS–PC system, with a target mean dry density
value of 1.40 Mg/m³. The samples were therefore expected, within experimental error, to be
of the same density and volume for all the material compositions in a given stabilizer system.
Although this means that, within each system, specimens of different composition may
deviate slightly from their MDD and OMC values, the minor variation in void space which
this will produce would be expected to have insignificant effect on the physical properties.
Dry materials for three compacted cylindrical test samples of dimensions 50 mm diameter and
100 mm in length were thoroughly mixed in a variable speed Kenwood Chef major KM250
mixer for 2 minutes before slowly adding the calculated amount of water. Intermittent hand
mixing with a palette knife was done for another 2 minutes to achieve a homogeneous mix to
ensure that the full potential of stabilization was realized. The materials were compressed
immediately after mixing into cylinders, to the prescribed dry density and moisture content. A
steel mould fitted with a collar to accommodate all the material required for one sample, was
used. Compaction, carried out immediately after mixing, was achieved using a hydraulic jack.
The prefabricated mould, which was oiled to reduce friction, ensured that no further
compaction was subjected to the soil once the desired volume had been attained. The
compacted cylinder was left in the mould under pressure for about 2 minutes, in order to
allow for the sample stability and/ or relaxation. The cylinders were then extruded using a
steel plunger, trimmed, cleaned of releasing oil, weighed, and wrapped in cling film.
The cylinders were labeled and placed in polythene bags before being placed in sealed plastic
containers. The samples were moist cured for 28 days at room temperature of about 20°C ±
2°C. Table 2 shows the details of the mix compositions used.
At the end of the 28 days of moist curing, three samples per mix proportion were removed
from the curing room. Any condensation on the cling film covering the cylinders was
removed with paper tissue, prior to their being weighed. A Hounsfield testing machine
capable of loading up to 10 kN was used to apply the load at a compression rate of 1 mm/min.
A special self-leveling device was used to ensure uniaxial load application. The samples were
then subjected to unconfined compressive strength tests in accordance with the British
standard BS 1924-2 [9], and then the mean strength of the three test specimens was
determined.
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Table 2: Detail of mix composition for the koalinite-lime-cement-GGBS system
Stabilisers
Mix
Lime (L)
Cement (PC) GGBS
code
content (%)
content (%) content (%)
20%L 0%PC
20 (control)
0
0
14%L 6%PC
14
6
0
8%L 12%PC
8
12
0
4%L 16%PC
4
16
0
0%L 20%PC
0
20 (control)
0
20%L 0%GGBS
20 (control)
0
0
14%L 6%GGBS
14
0
6
8%L 12%GGBS
8
0
12
4%L 16%GGBS
4
0
16
0%L 20%GGBS
0
0
20 (control)
20%PC 0%GGBS 0
20 (control)
0
14%PC 6%GGBS 0
14
6
8%PC 12%GGBS 0
8
12
4%PC 16%GGBS 0
4
16
PC - GGBS 0%PC 20%GGBS 0
0
20 (control)
L - PC
L - GGBS
3
Results
3.1 Effect of various stabilizers on strength development
Figure 1 shows the strength development using the L – PC blends. Each plot is an average of
three test specimens. A reduction in the proportion of lime (and increase in the quantity of
PC) from 20%L:0%PC to 4%L:16%PC shows a significant increase in strength development
of the stabilized mixtures from 693kN/m² to 1756kN/ m². This is approximately 153%
increase in the strength value. Further reduction in lime dosage and increase in the PC content
to 0%L:20%PC demonstrates a reduction in strength of the blend to 1515kN/ m², representing
approximately 14% reduction in strength.
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Industrialised Construction
28 day UCS kN/m²
2200
1725
1250
775
300
20%L:0%PC
14%L:6%PC
8%L:12%PC
4%L:16%PC
0%L:20%PC
Stabiliser levels
Figure 1: 28 - day unconfined compressive strength of LOC stabilized with various L - PC blend at a binder
content of 20% and 30% moisture content
Figure 2 shows the strength development using the L–GGBS blends. A reduction in the
proportion of lime and increase in the quantity of GGBS from 20%L:0%GGBS to
4%L:16%GGBS shows a significant strength increase from 639kN/m² to 2077kN/m²
(approximately 200% increase in strength). However a further reduction in the lime content
and increase in the quantity of GGBS to 0%L:20%GGBS results in a 14% decrease in
strength value as was the case for the L–GGBS blends.
28 day UCS kN/m²
2200
1725
1250
775
300
20%L:0%GGBS 14%L:6%GGBS 8%L:12%GGBS 4%L:16%GGBS 0%L:20%GGBS
Stabiliser levels
Figure 2: 28 day unconfined compressive strength of LOC stabilized with various L - GGBS blend at a binder
content of 20% and 30% moisture content.
Figure 3 shows the strength development using the PC – GGBS blends. A
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
28 day UCS kN/m²
2200
1725
1250
775
300
20%PC:0%GGBS 14%PC:6%GGBS 8%PC:12%GGBS 4%PC:16%GGBS 0%PC:20%GGBS
Stabiliser levels
Figure 3: 28 day unconfined compressive strength of LOC stabilized with various PC - GGBS blend at a binder
content of 20% and 30% moisture content
reduction in the quantity of PC and increase in the quantity of GGBS from 20%PC:0%GGBS
to 4%PC:16%GGBS shows a significant increase in strength development as previously
observed with the L – PC and L – GGBS stabilisers. In this instance, the strength increased
from 1515kN/m² to 1938kN/m², approximately 28% increase in strength (compared with 153
– 200% increase observed previously). As observed with the other blends, a further reduction
in the PC dosage and increase in the quantity of GGBS from 4%PC:16%GGBS 0%PC:20%GGBS results in a decrease in strength value by 8%
3.2 Effects of varying compaction moisture content
Figure 4 shows the effects of varying the compaction moisture content of the L – PC, L –
GGBS and PC – GGBS clay mixtures stabilized using the various blended stabilizers at
stabilization level 4%:16% . Overall a significantly high strength value of about 2077kN/m²
was observed at 30% moisture content at the end of the 28-day moist curing period for the
mixture with 4% lime and 16% GGBS. Further reduction in strength was then observed when
the moisture content was increased further to 40%, or decreased to 25%.
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Industrialised Construction
25%m/c
30%m/c
35%m/c
40%m/c
2200
28 day UCS kN/m²
1725
1250
775
300
L - PC
L - GGBS
PC - GGBS
Stabiliser levels
Figure 4: Effects of varying moisture content on strength of the L– PC, L– GGBS and PC– GGBS blended stabilizers at stabilization level
4%:16%.
3
Discussion
Due to evaporation, hydration and cracking/expansion, there is a tendency in practice to
compact stabilised material on the wetter side of the OMC. The MDD value for the
unstabilised LOC was observed at 29%, and it is therefore reasonable to observe maximum
strength at 30% MC. In practice, a MC of 30-35% would be adopted.
The highest strength values are most probably observed at certain blending and moisture
conditions when there is formation of relatively higher amounts of C-S-H gel compared to
other blending or moisture conditions. Previous researchers [10], [11] have attributed
increased strength in both PC-blend and pozzolanic reactions to the formation and subsequent
changes in the nature of the C-S-H gel. With the decrease in moisture content from 30% to
25% an appreciable reduction in strength values was observed in the blends with L – PC, L –
GGBS and PC – GGBS at stabilization level 4%:16% for all mixtures. The changes in
strength with decreasing moisture content would probably be due to poor compaction. With
an increase in moisture content from 30% a decrease in strength was observed in all the
blends at the stabilization level 4%:16%. This phenomenon relates to the fact that the higher
moisture content well above the OMC, does not promote the formation of a stronger bond due
to the increased void volume
Based on the laboratory results it was observed that there is an economic as well as an
environmental advantage from using the L – GGBS system with or without PC to stabilize
lower oxford clay for unfired clay brick building material production. Higher strength values
are likely to be achieved by either increasing the mass density of the sample, and /or a better
compaction effort, at 30% moisture content. Further tests, such as those for durability and
expansion are ongoing and will be reported at a later stage. It is anticipated that this
technology will help reduce the energy costs of the firing process, reduce the environmental
damage associated with manufacturing using traditional stabilizers, and thus, reduce
greenhouse gas emissions that contribute enormously to global warming.
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In terms of energy usage and CO2 emission the effect of conventional materials is intensive.
One tonne of manufactured PC results in the emission of at least one tonne of CO2 to the
atmosphere [12] with an energy usage of about 5000MJ [13] while the equivalent energy
usage of one tonne of GGBS used in this current work to manufacture unfired clay building
bricks is 1300MJ with a corresponding CO2 emission of just 0.07 tonnes [13]
In view of the positive developments of the research work pilot industrial trials were
established. A full-scale steel mould that would produce full-size bricks was fabricated to
produce building bricks using the L-GGBS mixture at a laboratory scale. The results were an
immediate success, as demonstrated in figure 5.
Figure 5: Laboratory scale brick making, showing a freshly compacted brick made using L-GGBS blend.
5
Conclusion
The results obtained suggest that there is potential for use of blended binders for the
manufacture of unfired clay based product within the building construction industry which
will help reduce energy usage and CO2 emission. The following conclusions may therefore be
drawn from this investigation reported in this paper.
1. Using Lower Oxford Clay as the target stabilisation material, the L – PC and PC – GGBS
blends tended to achieve lower strength values compared with the L - GGBS blends.
2. Research shows that the combination of lime and GGBS may have other benefits in
performance such as durability and volume stability. These added benefits need to be
investigated in future research studies with a specific focus on building components. However
marginally lower strength values alone cannot rule out the application of L – PC and PC –
GGBS blends.
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Industrialised Construction
3. This is a preliminary investigation and higher strength values are likely to be achieved by
increasing the mass density of the test samples together with a higher compactive effort in
future experiments.
Acknowledgement. The authors wish to thank Dr. David Snelson for his assistance in
structuring this manuscript.
References
1. Spence, R., Mulligan, H.: Sustainable Development and the Construction Industry.
Habitat international, Vol. 19, No. 3 (1995) 279-292
2. Wild, S., Kinuthia, J.M., Jones, G.I., Higgins, D.D.: Effect of Partial Substitution of Lime
with Ground Granulated Blast-furnace Slag (GGBS) on the Strength Properties of Limestabilized Sulphate-bearing Clay Soils. Engineering Geology, Vol. 51 (1998) 37-53.
3. Venkatarama Reddy, V.B., Lokras, S.S.: Steam–cured Soil Blocks for Masonry
Construction. Energy and Building Vol. 29 (1998), 29-33
4. Oti, J.E.: Sustainability: Development of Unfired Clay Building Materials, Paper
Presented at the 2nd Research Students Workshop, University of Glamorgan, Pontypridd
UK (2007) 1st November ISBN: 978-88054-179-3
5. Oti, J.E., Kinuthia, J.M., Bai, J.: Innovative Building Material: Manufactured Bricks
Using By-product of An Industrial Process, Proceedings of the 3rd Research Student
Workshop, University of Glamorgan, (P.A Roach and P. Plassmann (Ed)) Pontypridd,
(2008) pp. 42-45. ISBN: 978 – 1- 84054-193-9
6. ODPM - Office of the Deputy Prime Minister Brick Clay.: Mineral Factsheet. ODPM
(2005) Nov.
7. Brookes, A.H., West, G., Carder, D.R.: Laboratory Trial Mixes for Lime- Stabilised Soil
Columns and Lime Piles. Transport Research Laboratory, Crowthorne (1997) Report 306
8. British Standards Institute: Cement - Part 1: Composition, Specification and Conforming
Criteria for Common Cements (BS EN 197-1: 2000).
9. British Standards Institute: Stabilised Materials for Civil Engineering Purposes - Part 2:
Methods of Test for Cement-stabilised and Lime- stabilised Materials, (BS 1924-2: 1990).
10. Wild, S., Kinuthia, J.M., Jones, G.I., Higgins, D.D.: Suppression of Swelling Associated
with Ettringite Formation in Lime Stabilized Sulphate Bearing Clay Soils by Partial
Substitution of Lime with Ground Granulated Blastfurnace Slag. Engineering Geology
Vol. 51 (1999), 257-277
11. Gollop, R.S., Taylor, H.F.W.: Microstructure and Micro-analytical Studies of Sulfate
Attack V: Comparison of Different Slag Blends. Cement and Concrete Research Vol. 26,
(1996) 1029-1044.
12. Wild, S.: Portland Cement Binders: Science and Sustainability. International Symposium
Celebrating Concrete: People and Practices. University of Dundee, Scotland, 3-4th
September, Role of Cement Science in Sustainable Development. keynote Paper, Thomas
Telford Ltd, London, Editor Dhir, R.k., Newlands, M.D., Csetenyi, L.J. (2003) 143-159
13. Higgins, D.: GGBS and sustainability, Proceedings of ICE, Construction Materials Vol.
160, Issue3 (2007) pg 99-101
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Future Directions for Building Services Technologies in Denmark
Dr. Rob Marsh1
1 Danish Building Research Institute, Department for Building Design & Technology
Dr Neergaards Vej 15, DK-2970 Hoersholm, Denmark
e-mail: [email protected]
Abstract
The hypothesis of this paper is that industrial transformation in the Danish construction sector needs in the future to focus on
integrating building services technologies into the buildings. This can be illustrated by analysing historical developments in
building services usage, exploring design strategies for the effective integration of building services, and by developing new
industrialised solutions for building services. The paper is based on the current Danish situation, and is based on linking
research on building services, user needs, building design and new industrial processes.
Keywords
Building services, Intelligent buildings, Integrated building design, Industrialisation.
1
Introduction
Over the last 100 years there has been a large increase in the extent of these building services,
with Nordic data showing a large growth in building services' share of total office
construction costs. Today's buildings need many different building services to create the
necessary functionality that users demand, and the growing importance of building services
show perceptions of buildings are changing:
- From static and passive constructions providing the basic functions of climatic tempering.
- To dynamic and adaptable functional spaces, where intelligent building services are the
driving force in providing for changing user demands.
Despite the growing importance of building services, they have not been a central focus for
the construction sector's industrialisation. The largest productivity gains from industrialisation
can therefore be achieved by focusing on building services because they are a growing
proportion of total construction costs, and they represent the least industrialised part of the
construction process. The hypothesis of this paper is therefore that industrial transformation in
the Danish construction sector needs to focus on integrating building services technologies in
the buildings of the future. This paper is based on current Danish research and practice into
building services, user needs and industrialisation, and has the following objectives:
- To analyse the historical development of building services provision in Denmark.
- To understand in a broader perspective how building services provision can be linked to
processes of social and technological change in satisfying user needs.
- To explore strategic design principles for the integration of building services technologies
into buildings, so that changing user demands can be incorporated into the building design
and procurement process.
- To analyse how building services technologies can be modularised and prefabricated, so
that greater value is created for clients and users by reducing construction costs/time and
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improving construction quality.
2
Historical Development of Building Services Provision in Denmark
Today's buildings need many different building services to create the required functionality
that building users demand, and over the last 100 years there has been a considerable increase
in the numbers and extent of these building services [1]. This transformation is also visible in
Denmark and the other Nordic countries:
- Nordic data relating to the construction costs of offices show that the building services'
share of the total costs has risen from 5% in 1900, to 23% in 1950, and further to 40% in 1990
[2], as shown in figure 1. Comparable data for several countries in North America and Europe
show similar trends [3].
- Danish data relating to time usage on construction sites for housing projects shows that
time consumption used on the building services has grown from 6 % of the total construction
time in 1951 to 20 % in 1994 [4], [5].
Fig. 1. Construction costs in relation to different construction elements for Nordic office buildings from 1900 to
1990.
The historical development of building services in Denmark can be divided into three phases
[6]. During the period from the 1850's to the 1940’s, the first foundations for the industrial
society were laid, and urban areas experienced a very large growth. The basis for these
transformations was the introduction of the first modern ideas relating to public health [7]. In
a Danish context, the first building services in the form fresh water supplies and wastewater
disposal systems were provided for housing areas in the larger urban centres with the aim of
improving the growing population’s health. In terms of building design, these changes meant
that new functions were provided for in buildings, and that this resulted in a design and
construction rationalisation, where kitchen and bathroom functions were placed close to each
other to minimise the extent of vertical ducts to water supply and wastewater drainage in
housing [8].
During the period from the 1940's to the 1980’s, rapidly advancing technological
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
developments, such as mechanical ventilation, air conditioning and artificial lighting, allowed
the provision of higher levels of comfort in buildings that were independent of the building
fabric's traditional climatic regulation. These technological transformations led to the
development of the new building types, characterised by the international style of modern
architecture [1], where very deep buildings became possible, and very light curtain wall
façade systems with large glazing areas became the norm, allowing for rationalised
construction processes. In the nordic countries, the development of central heating and district
heating systems meant that fireplaces became functionally obsolete, and this in turn meant
that independent ventilation systems became necessary [9]. These ventilation systems were
typically placed in conjunction with the already existing vertical ducts for water supply.
From the 1980's and onwards, developments within the field of information technology have
led to a vast and continuing growth in the provision of so-called intelligent building services
[10]. This development covers many aspects:
- Knowledge: The extensive use of IT has allowed the growth of modern knowledge-based
businesses, where ‘New Ways of Working’, innovative and creative working patterns
supported by adaptable workspaces, are a competitive prerequisite and a driving force in
modern business models [11].
- Entertainment: The growth in IT, multimedia and communication technologies in today's
households, including the development of so-called smart-house systems [12]. These
technologies are also responsible for the rapid growth in household electrical consumption.
- Control: The growth of intelligent control systems in all buildings, especially related to
facilities management and the environmental control of energy use, indoor climate, etc. [13].
These systems typically add a new layer of intelligent control on the top of existing building
services.
3
Processes of Change and Building Services Provision
Modern society can be characterised by continuing and fluid processes of social and economic
change [14], and these processes naturally affect the perception and use of buildings. For
offices, IT and the knowledge economy mean that dynamic business processes demand that
both employees' and the building's ability to adapt over time are seen as innovative
competitive prerequisites in their own right [15]. For housing, both lifestyle and demographic
changes are affecting the way that housing is perceived [16], and this is reflected in new
housing developments in Copenhagen such as the ON:HOUSE project, which is now being
innovatively branded in relation to the internet and multimedia lifestyles.
An important aspect relating to the development of building services is their role in providing
the new levels of intelligent functionality which building users' demand [6]. This can be in
satisfying user requirements in relation to both improved comfort control and newer IT and
multimedia services. Another important aspect is how services become 'layered' in the
transition from traditional low technology services to newer intelligent services with a high
technology content. It can for example be argued that building services do not disappear, but
low technology solutions become replaced or augmented by newer intelligent solutions [13].
With building services being responsible for a large proportion of buildings' functionality, it is
now possible to see a transformation in how buildings are used and perceived [17]:
- From the historical view of buildings as static and passive constructions, where concrete
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Industrialised Construction
and brickwork were responsible for basic functions relating to shelter and climate tempering.
- To a newly developing view of buildings as dynamic and adaptable functional spaces,
where intelligent building services are the driving force in meeting users' changing functional
requirements over time.
4
Strategies for the Integration of Building Services Technologies
It is clear that the processes of social, technological and economic change described above,
together with the increasing use of new building services technologies, puts focus on the
design and procurement of buildings. Principles for building services design and distribution
need therefore to be integrated with principles for managing building usage and change early
in the building design and procurement process [10].
This integration can be highlighted by looking at the historical development of office design
from the 1950’s to today [6]. In the first office buildings of the Modern Age, as described
above, it was very typical for the vertical services ducts to be placed in connection with toilet
and kitchen facilities in the service zones on each floor, since it was in these areas that the
majority of the traditional building services were located. This decision can be seen rational in
terms of minimising construction costs.
However, in the following years, because of the functional and technological transformations
ushered in by the Intelligent Age, there has been an explosive growth in the extent of building
services located in the office zones. This growth includes new IT, communications and data
systems, and extensive ventilation and cooling systems to control the indoor climate because
of the growth in electrical and electronic equipment found in these office areas. However, this
transformation of building services requirements has not resulted in fundamental changes in
design strategies for building services provision. The vertical ducts have been enlarged and
are still centralised in the service zones, whilst they are now accompanied by large horizontal
ducts to ventilation, which have become very deep because of the large floor areas that are
serviced and the large air volumes to be transported. It is now typical for many new nordic
office developments that between 25 and 33 % of the total floor to floor height is used to
horizontal service ducts hidden behind suspended ceilings [2].
As an alternative to the traditional centralised building services systems, newer nordic
research has pointed towards the advantages of utilising a decentralised distribution of the
building services [2], [6]. The traditional centralisation of the office's vertical ducts may mean
increased construction costs as a consequence of the extensive horizontal ductways and the
increased storey height. It may also result in a reduced capacity for change and higher
operating costs since the changes affect the functionality of the whole system. In contrast,
studies show that there may be many advantages attached to a decentralisation of the building
services ducting when the objective is to create innovative and intelligent workplaces:
- The office of the future should have relatively large and open floor areas that permit ‘New
Ways of Working’ with innovative work processes and changing functional requirements.
- It should be possible to partition off these large and open floor areas into smaller
decentralised function zones providing improved possibilities for individual control in relation
to the desired functional requirements.
- The building services can advantageously be ducted decentrally in the building facade,
which will provide the best possibilities for creating uninterrupted continuous office spaces
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
with several smaller function zones [6].
5
Industrialisation of Building Services Technologies in Denmark
There has been very little research or development work relating to the industrialisation of
building services in Denmark. This has its roots in the traditional nature of the Danish
construction sector, where building services engineers and contractors typically become
involved very late in the procurement process, despite the growing proportion of construction
costs connected with building services. The building services sector has therefore never been
in a situation to set the agenda for the construction sector’s future development. However, a
preliminary study [18] has shown that the industrialisation and prefabrication of building
services in Denmark can reduce total construction costs and times whilst also improving the
technical quality of buildings.
In Denmark the interaction between client, consultant and contractor has historical roots,
where the organisation of the building industry has been dominated by economic demands
relating to the historically relatively high construction costs of the loadbearing structure. A
demand for greater efficiency has meant that the main efforts to industrialise the construction
industry in Denmark have focused on the use of prefabricated concrete elements for
buildings’ loadbearing structures and facade elements [19]. This has resulted in reductions in
construction costs and construction times for these elements. However, over time greater
functional demands to buildings have resulted in the growth of building services, which
means that they have come to make up a far greater share of the total construction costs.
This dichotomy causes a number of conflicts between the traditional organisation of the
building process and the new functional reality of buildings. The specification of building
services is often decided at a late stage in procurement, which makes it difficult for
installation to be carried out rationally. At the same time it can also be seen as paradoxical
that building services, which already consist of prefabricated industrial (and often technologyadvanced) products, are built into buildings in a handbuilt and craftsmanlike way because of
tradition.
Studies from the UK have shown that considerable productivity increases in terms of reduced
construction costs and construction times can be found by prefabricating building services
[20], [21], [22]. In a Danish context, it can therefore be argued that the largest productivity
gains from industrialisation can be achieved by focusing on building services because they are
responsible for a growing proportion of total construction costs, and they represent the least
industrialised part of the building process.
To explore the possibilities of industrialising building services provision in Denmark, a study
has been carried out based on design and construction cost data for a typical office building.
Construction cost data shows that this building has a construction price of 2.215 Euro/m2 at
2005 prices [23], and that the building services account for about 30 % of this amount, as
shown in figure 2.
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Industrialised Construction
Fig. 2. Construction costs for typical office.
The construction costs for the individual building service type can be further broken down
with data relating to the weighting of the total costs in relation to the building services
distribution hierarchy, that is from the main supply, through the plant room, vertical
distribution and horizontal distribution, to the local services distribution in each room [2]. By
taking each individual building service type that is supplied to the office space, and breaking
the construction costs down in relation to the distribution hierarchy, it is possible to see where
the largets proportion of the construction costs is placed, as shown in figure 3.
Fig. 3. Construction costs for distribution hierarchy of building services for typical office.
From figure 3 it can be seen that:
- The building services in the loft space, comprising the horizontal distribution (126
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Euro/m2) and local services (134 Euro/m2), comprise the largest component of the building
services construction costs at 260 Euro/m2.
- The plant room has the second highest construction cost at 140 Euro/m2.
It can therefore be argued that if building services are to be industrialised, then the largest
cost and time related advantages are to be found by focussing attention on the building
services with the largest construction costs, that is the horizontal distribution and local
services located in the loft. These elements account for approximately half the total
construction costs of the building services, which again equates to between 10 and 15 % of
the office building’s total construction costs.
The most effective solution is therefore to focus on developing prefabricated and modular
elements to the distribution of all relevant building services types in the loft space of offices,
as shown in figure 4. These modules can be used in conjunction with both traditional
centralised solutions and the previously suggested decentralised, façade integrated solutions.
Fig. 4. Prefabricated building services elements to loft for typical office.
6
Conclusions
The hypothesis of this paper is that the Danish construction sector's industrial transformation
needs to focus on integrating building services technologies in the buildings of the future. In a
Danish context, the conclusions of the research work presented in this paper are as follows:
- An historical analysis shows there has been a large growth in the extent and costs of
building services technologies over the last 100 years, and that this growth can be linked to
changes in social and technological development. Comparable data for several countries in
North America and Europe show similar trends.
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Industrialised Construction
- By linking changing user demands and growing building services provision with processes
of social and technological change, it can be seen that perceptions of buildings are changing
from static and passive constructions to dynamic and adaptable functional spaces. In this
process, intelligent building services are becoming the driving force in meeting users'
changing functional requirements over time.
- New strategic design principles can be developed to integrate and distribute the expanding
range of building services into buildings, so that changing user demands for new intelligent
building services technologies can be incorporated into the building design and procurement
process.
- An analysis of Danish office buildings has been used to show that it is best to focus
attention on developing prefabricated and modularised building services elements for the
horizontal distribution and local services located in the loft, so that greater value is created for
clients and users by reducing construction and renewal costs/times, and improving
construction quality.
The presented research draws together aspects relating to building services provision,
changing user needs, building design and new industrial processes. It is clear that the growing
building services provision is closely related to changing user needs and perceptions. From a
Danish standpoint this points in the direction of new design and procurement processes which
reflect these patterns, and a greater need for the use of prefabricated and modularised building
services elements. This is because the largest productivity gains from industrialisation can be
achieved by focusing on building services because they represent both a growing proportion
of total construction costs, and the least industrialised part of the construction process.
Current processes of social and technological change also point towards the growing
importance of IT and the knowledge economy. In terms of building services technologies, this
implies that one can expect a growth in existing IT-related building services, and also the
development of new types of building services technologies. This can span from energy
saving low voltage electrical power distribution systems used to power the growing numbers
of electronic appliances and equipment in buildings, to the use of pervasive computing
technologies where IT and building surfaces melt together. These developments point towards
the fact that the importance of building services technologies will continue to grow in the
buildings of the future.
References
1. R. Banham (1984) The Architecture of the Well-tempered Environment. Second Edition.
The Architectural Press, London.
2. T. Wigenstad (2000) Optimisation of Ducting Routes for Building Services in Buildings
(PhD Dissertation 2000:62) [in Norwegian]. Norwegian University of Technology and
Natural Sciences (Norges teknisk-naturvitenskapelige universitet), Trondheim.
3. K. Walsh and A. Sawhney (2004) International Comparison of Cost for the Construction
Sector. Report Submitted to The African Development Bank & The World Bank Group.
4. B. Wille (1990) The Construction Sector’s Resource Consumption and Distribution. A
pilot analysis (BUR-report) [in Danish]. Construction Development Council (Byggeriets
Udviklingsråd), Copenhagen.
5. M. Høgsted (1995) Analysis of the Construction Sector’s Productivity, Resource
Consumption and Time Usage in Social Housing Sector (Report) [in Danish].
Construction Development Council (Byggeriets Udviklingsråd), Copenhagen.
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6. R. Marsh (2007) Construction and Building Services. SBi2007:02 [in Danish]. Danish
Building Research Institute (Statens Byggeforskningsinstitut), Hørsholm.
7. R. Macdonald (1989) The European Healthy Cities Project. Urban Design Quarterly,
(30), 4-7.
8. R. Marsh & M. Lauring (ed.). Housing and Natural Ventilation [in Danish]. The School
of Architecture’s Publishing House (Arkitektskolens Forlag), Aarhus.
9. B. Kjessel and M. Carlsson (1995) Architecture and Building Services [in Swedish].
Foundation ARKUS (Stiftelsen ARKUS), Stockholm.
10. D. Clements-Croome (ed.) (2004) Intelligent Buildings: Design, Management and
Operation. London: Thomas Telford.
11. F. Duffy, J. Jaunzens, A. Laing and S. Willis (1998) New Environments for Working.
London: Spon Press.
12. Sandström, U. Keijerand & I.B. Werner (2003) Smart Homes Evaluated. Open House
International, 28(4), 14-23.
13. G. Baird (2001) The Architectural Expression of Environmental Control Systems. London:
Spon Press.
14. Z. Bauman (2000) Liquid Modernity. Cambridge: Polity Press.
15. K. Arge and K. Landstad (2002) Generality, Flexibility and Elastisicity in Buildings
(Project Report 336) [in Norwegian]. Norwegian Building Research Institute (Norges
byggforskningsinstitutt), Oslo.
16. P.G. Krogh and K. Grønbæk (2001) Architecture and pervasive computing - when
buildings and design artifacts become computer interfaces. Nordic Journal of
Architectural Research, 14(3), 11-22.
17. D. Gann (2000) Building Innovation: Complex Constructs in a Changing World. London:
Thomas Telford.
18. R. Marsh (2006) iTekq: Building Costs and Market Analysis (Unpublished report). Danish
Building Research Institute (Statens Byggeforskningsinstitut), Hørsholm.
19. S. Bertelsen (1997) Bellahøj . Ballerup . Brøndby Strand. 25 years that Industrialised the
Construction Sector [in Danish]. Danish Building Research Institute (Statens
Byggeforskningsinstitut), Hørsholm.
20. M. Dicks (2002) Innovative M&E Data Sheets (ACT 5/2002). Bracknell: Building
Services Research and Information Association.
21. M. Mawdsley, G. Long, A. Brankovic, G. Connolly and Q. Leiper (2001) Effects of
modular building services distribution on construction sequence, time and cost. In: CIBSE
National Conference, Regents College, 2001. London: Chartered Institution of Building
Services Engineers.
22. D. Wilson (2000) Innovative M&E Installation Report (ACT 9/2000). Bracknell: Building
Services Research and Information Association.
23. V&S Byggedata (2005) V&S Price Books: Constructional Elements 2005 [in Danish].
V&S Byggedata A/S, Ballerup.
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Technology Monitoring in Construction: a Concept for Internet
Supported Identification of Experts in the Definition of the Search
Field for Technology Monitoring
Sven Schimpf1
1 Competence Center R&D Management, Fraunhofer Institute for Industrial Engineering
Nobelstrasse 12, 70569 Stuttgart, Germany
[email protected]
Abstract.
This paper describes a new concept for the Internet supported identification of experts in the definition of the search field for
technology monitoring that takes into consideration the special requirements of the construction industry. This is done by a
structured approach using the concept of technological definition in combination with the identification of experts for the
identified technologies to further evaluate specific technologies for applications in the constructions sector. The research
activity was carried out in the context of the research project I3CON that is funded in the 6th European Framework
Programme
Keywords
Construction, Technology Intelligence, Technology Monitoring, Internet.
1
Growth of Technology in Built Environments
Construction represents, with one quarter of total industrial output the largest industrial
cluster in the EU6. Despite this, the investments in research and technological development
are today with less than 1% of the turnover relatively low compared to other industrial sectors
[7, p.100]. Buildings in their traditional definition are custom-built products with a relatively
low level of technological complexity. Therefore, also the constant monitoring and planning
of technological developments and their integration lags behind other industries [1, p.511].
But the requirements towards the construction industry are changing. The level of
technological complexity in buildings is constantly increasing through the application of
advanced information and building automation technologies and the application of hightechnology materials. At the same time construction companies are faced by an integration of
the building life-cycle. The application of alternative business models such as public private
partnership or the public financing initiative is integrating operation, maintenance and
refurbishment already in early building design phases. This leads to increased necessity of
multidisciplinary technological awareness in product, process and service design of buildings.
Latest technology developments hereby play an important role in the progress towards
intelligent, industrially manufactured and integrated built environments.
A technology monitoring system that is adapted to the requirements of the construction
industry can hereby improve the short- and long-term oriented planning of technological
developments and their efficient integration in today's and future buildings.
6
http://www.fiec.org, Dec07, EU: European Union
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Industrialised Construction
2.
Challenges of Technology Monitoring in the Construction Sector
The construction industry is focused on custom-built products and thereby differs from mass
production-oriented industries. Also, the major player in the construction industry, the general
contractors are only to a small part involved in technological development. They are more
focused on the integration and application of available technologies. Another factor that
differentiates the construction sector from other sectors is that the construction sector works
mainly in a project organisation in which multidisciplinary teams in a temporary organisation
develop and deliver products [5, p.105]. Thus existing methods and instruments for
technology monitoring have to be measured against the requirements of the construction
industry.
One of the key challenges in technology monitoring is that almost no industry specific
solutions exist [6, p.379]. Especially in industries where each single product is adapted to the
customer requirements the traditional methods of technology monitoring are too resource
consuming to apply them for each new product [10, p.31]. The adaptation of the methodology
to the specific industrial requirements under consideration of new information technologies
are in the focus of this work. Based on this underlying methodology, possibilities for the use
of supportive ICT 7, especially the use of the Internet, will be evaluated.
3
Objective and Research Methodology
The objective of the developed concept is to improve the monitoring of technological
developments to better plan and integrate technological developments, applications and their
integration in built environments. The target group are major construction companies in their
role as general contractors. To achieve this objective, a study about the actual state and future
requirements has been carried out with some of the major European construction companies 8.
In a second step, an ICT based concept was developed to meet these requirements and support
the technology monitoring process in the construction sector through adapted methods and
tools. As a basis for structuring the technology monitoring process, a generalised process of
information treatment in the technology monitoring process is considered.
1
Definition of the
search field for
technology
monitoring
2
Collection of
information on
technological
developments
3
Evaluation of
information on
technological
development
4
Storage of
information on
technological
developments
5
Communication
of information on
technological
developments
Fig. 5. Generalised Technology Monitoring Process [6, p.31][2, p.40]
This paper will provide a first concept for an ICT supported methodology that should support
the early phases of the technology monitoring process that is described in figure 2. In the
actual research activity it is planned to cover the entire process of technology monitoring
according to the requirements of the construction sector.
4.
Actual State of Technology Monitoring in the Construction Sector
Technology monitoring in the construction sector compared to other sectors is still in an early
stage and done in most cases in an unstructured and non-coordinated way. The search field for
7
8
ICT: Information and Communication Technology
Semi structured interviews with 14 of the major European construction companies representing component suppliers and
general contractors carried out between July and November 2007.
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the monitoring of technological developments is done mainly in a bottom-up approach in
which relevant technological fields are defined by business units or geographic units based on
project or customer requirements. After the definition of the search field it can be generally
observed that secondary information sources are used in early phases to get first information
on technological developments and to identify so-called weak signals. As one of the most
common source of secondary information, the Internet is still gaining importance in this
context. As soon as a technological field has been evaluated as being relevant, primary
information sources are used to collect more specific information about the technology and its
application in the construction sector. In this context, internal and external experts as a source
of primary information play the most important role. The evaluation of the information about
technological developments is carried out principally on two levels. The first level of
evaluation is done individually by the people who are collecting the information. This level is
mainly based on individual operational expertise. The second level of evaluation is done by
the technical unit, specific committees, or general management and is based on strategic,
technical and commercial criteria. Information that is collected and evaluated positively is
mainly stored on general internal intranet websites. Only few organisations have explicit
information systems for the storage of technological information. The communication of
relevant technological developments is done in two ways. Technological options that are
identified in the technology monitoring process are mainly communicated in an informal
bottom-up approach to the management level or directly to the appropriate internal experts
responsible for their application. Then, in a next step, they are communicated to a wider
community through specific meetings, innovation forums, Intranet or company newsletters.
Structured formulation and regular
update of the search field.
1
Definition of the
search field for
technology
monitoring
2
Clear guidelines and checklists for the
evaluation of technological options on
all levels.
Collection of
information on
technological
developments
3
Evaluation of
information on
technological
development
Collection of information on all organisational
levels from defined information sources.
4
Communication of information about
technological information to the right
people.
Storage of
information on
technological
developments
5
Communication
of information on
technological
developments
Structured storage system for technological
information with clear responsibilities for
keeping the information updated.
Fig. 6. Requirements towards Technology Monitoring in Construction
Information Technologies in addition to common office applications that are used in the
technology monitoring process in construction are the Intranet solutions that are partly
enhanced by specific knowledge management or expert database systems. Most people
involved in technology monitoring have constant Internet access but only use it on an
individual and unstructured level to find information about new technological options through
common search engines or information portals. Also patent search engines are frequently used
to collect information about relevant technological developments. Thus the approach that is
described in the following chapter focuses on a methodology including the structured use of
the Internet for the identification and integration of experts in early phases of the technology
monitoring process.
5.
A Concept for Internet Supported Identification of Experts in the
Definition of the Search Field of Technology Monitoring
The presented concept focuses mainly on the operational identification and specification of
relevant technological fields and the identification of internal and external experts for further
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Industrialised Construction
specification and evaluation of these fields for the application in built environments. Two
major phases will be taken into account in this context:
1.
Technological decomposition of construction products.
2.
Identification of internal and external experts for the specified technologies.
A schematic overview of the process is shown in figure 4 and will be described in more detail
in the following paragraphs. Before starting with the described methodology a first preselection of potential technological orientations has to be derived from the business strategy,
the economic and societal context of the organisation [9; p.162f]. This gives the general
context for the selection of products that are considered as an input for the definition of the
search field in the technology monitoring process.
1. Technological decomposition
Product
Function 1
Function 2
Function x
Technology x
Technology 1
Technology 2
1 Definition of the 2 Information
search field
collection
2. Identification of experts
Technology 1:
Expert 1, Expert... Expert x
Technology 2:
Expert 2, Expert... Expert y
...
Technology x:
Expert 3, Expert...Expert z
3 Information
evaluation
4 Information
storage
5 Information
communication
Fig. 7. Technological decomposition and expert identification to support the definition of the search field in the
technology monitoring process.
5.1. Technological Decomposition of Construction Products
The definition of relevant technologies in the definition of the search field is one of the most
critical phases to get to good results in the technology monitoring process. It guides the way
for all further activities. Especially for Internet supported search activities this is crucial as the
Internet contains a vast amount of unstructured information that is to a major part not indexed
in any standard manner. Herein, the technological decomposition of construction products can
lead to a significant reduction of complexity and allow focusing on specific technologies
linked to specific applications in one or several products. In general, the technological
decomposition should be done on the basis of existing standards or structures. At the example
of buildings on the German market, the assembly sections according to DIN 9 can be
considered as such a standard. The level of detail in the technological decomposition can be
adapted to the specific needs and can take into account different levels such as components,
subcomponents or technological fields to get from the product towards relevant technologies.
The number of levels taken into consideration in the technological decomposition depends on
the built environment and the required level of detail. As soon as the relevant technologies
have been defined, they should be further differentiated by e.g. the level of attractiveness of
the technology and the availability of internal resources [3, p.153]. The objective of this
differentiation is to identify the technologies that can be evaluated by internal experts and
those for which external experts are necessary for the evaluation. This allows a fast decision
about if a technology should be further taken into account and if external experts are
9
DIN: German Institute for Standardisation
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
necessary for the evaluation. The Internet can support this process by further defining
technologies for which no competence is available internally by a grid of keywords to better
identify external experts for the evaluation. Tools in the Internet that can support the
definition of a grid of keywords and help to define the functionality of a technology are
encyclopaedias (E.g. http://www.wikipedia.org) and cluster search engines (E.g.
http://www.kartoo.com). Through the use of encyclopaedias, the potential functionalities of a
technology can be specified on a rough level without external help and without pre-existing
knowledge on the field. For technologies where the competence is available in the
organisation, the definition of a grid of keywords can help to challenge actual applications and
to identify new applications.
5.2. Identification of internal and external experts
The identification of experts for the selected technologies has to be split up in the
identification of internal and the identification of external experts. For the identification of
internal experts for relevant technologies, internal expert systems, competence landscapes or
yellow page systems can support the process. They should be applied in the entire
organisation and bring together experts from all different units. The role of the Internet in this
context is to get in contact to external experts with whom no previous contact existed. This is
especially relevant for new technological fields, where it is difficult to evaluate the relevance
of specific technologies. Herein, the grid of keywords should be used to get valuable
information about experts in the field from search channels that are available through the
Internet. The following search channels to identify experts in the Internet are supposed to be
used in a structured way to get a good portfolio of different information sources [8, p.1287]:
• Internet search engines: The search of experts through Internet search engines is specified
through a high amount of available information and data of all qualitative levels. The quality
of the result depends highly on the quality of the grid of keywords that defines a specific
technology. Internet search engines will allow a first general overview on available
information and major players in the technological field. (Examples for Internet search
engines are: http://www.google.com; http://www.teoma.com; http://www.clusty.com)
• Research organisations: The search of experts through research organisations is the most
important channel for the search and identification of experts in a specified technological
field. The information that is available through this channel is in general of much higher
quality than information from other sources in the Internet. Publications have to be validated
from the research organisation before they are published and are looked at critically from the
research community. (Examples for research organisations and platforms for their
identification
are:
http://www.fraunhofer.de;
http://www.researchportal.net;
http://www.cordis.lu)
• Networks of competence, mailing lists and forums: The information sources in this
channel can also be defined as innovation communities [4, p.84] and described as interest
groups for a specific subject having a common space for information exchange, cooperation
and critical discussions. Thus it can be used in two ways for the search and identification of
experts: Firstly, it allows gaining an overview on existing discussions and newest
developments in the specified technological field. Secondly, the community can be
interactively addressed through specific questions in the technology field. (Examples for
networks of competence are: http://www.kompetenznetze.de; http://www.biovalley.com;
http://www.scanbalt.org)
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Industrialised Construction
• Publications: Publications are an important media for information on new technological
developments and allow an easy search and identification of experts. They are partly available
in structured formats in publication or journal databases and through specific search engines.
In general, publications are also accessible through general search engines, but seldom appear
as one of the first search results. Therefore, specific publications search engines or databases
should be used. The reference system in this channel also allows a first validation through
cross-checking contents and references in publications. (Examples for publication search
engines
are:
http://www.bpubs.com;
http://scholar.google.com;
http://www.ingentaconnect.com)
Using the different channels for the search and identification of experts should not be seen as
a strict and linear process. Already during the search activity, information from one channel
should be cross-checked, updated, validated or rejected through other channels. The
information found through the channel of search engines might be the most recent information
but is not validated concerning its credibility. If the same information is then identified on the
level of research organisations a higher level of credibility can be presumed. The result of this
phase should be a prioritised list of potential experts in the technological field including their
contact details. The use of different channels allows a first evaluation of the experts
concerning their core activities. Also it gives an overview about the acceptance of specific
experts in the research or business community that becomes visible through the number of
cross-links between different information sources. The prioritised list of experts is the basis
for the phase of information collection and finally to be able to evaluate a specific technology
in more detail concerning its application in the construction sector.
The definition of the search field is not a process that has to be carried out only once. This
phase has to be carried out continuously and to be updated regularly, depending on the
technological life-cycle of specific technologies.
6. Conclusion and further research objectives
Through high importance of internal and external experts for the process of technology
monitoring that was identified in the study on technology monitoring, it is of highest
importance to provide a structured approach to identify experts in relevant technological
fields. The Internet seems to be an appropriate information bases due to its high amount of
actual information. Based on both assumptions, the developed concept seems to have the
potential to reduce the effort that is necessary to identify experts for the support of the process
of technology monitoring dramatically.
The business benefit of the developed concept is an improved and more focused technology
monitoring process based on an early and structured formulation of the search field supported
by the use of the Internet. This should allow organisations in the construction sector to better
identify and plan technological developments and their applications. Especially for the project
based organisational structure of major construction companies the integrated planning of
technologies and the transfer and evaluation of their applications is a key factor to remain
competitive in the operational business.
A further challenge to be addressed in technology monitoring in the construction sector is the
increased level of globalisation and thereby dealing with language barriers, different regional
cultures and disruptive organisational structures.
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References
1. Betts, M., Ofori, G.: Strategic planning for competitive advantage in construction. In:
Construction Management and Economics, vol. 10 (6), (1992) 511-532
2. Bullinger, H.J.: Einführung in das Technologiemanagement - Methoden, Praxisbeispiele.
Teubner, Stuttgart (1994)
3. Gerpott, T.: Strategisches Technologie- und Innovationsmanagement. Schäffer-Pöschel
Verlag, Stuttgart (2005)
4. Gerybadze, A., Meyer-Krahmer, F., Reger, G.: Globales Management von Forschung und
Innovation. Schäffer-Pöschel Verlag, Stuttgart (1997)
5. Kamara, J.M., Anumba, C.J., Carrillo, P.: Cross-Project Knowledge Management. In:
Anumba, C.J., Egbu, C., Carrillo, P. (Ed.): Knowledge Management in Construction.
Blackwell Publishing Ltd, Oxford (2005) 103-120
6. Lichtenthaler, E.: Organisation der Technology Intelligence - Eine empirische
Untersuchung
der
Technologiefrühaufklärung
in
technologieintensiven
Grossunternehmen. PhD, Eidgenössische Techn. Hochsch. Zürich, Zürich (2000)
7. Morledge, R., Smith, A., Kashiwagi, D.T.: Building Procurement. Blackwell Publishing,
Oxford (2006)
8. Schimpf, S., Beucker, S.: An ICT-Supported Methodology for Expert Identification in the
Technology Monitoring Process. In: Cunningham, P., Cunningham, M. (Ed.): Exploiting
the Knowledge Economy. IOS Press, Amsterdam, p. 1284-1289 (2006)
9. Weule, H.: Integriertes Forschungs- und Entwicklungsmanagement: Grundlagen,
Strategien, Umsetzung. Hanser, München (2002)
10. Wille, J.H.: Eine Methode zur Schaffung von Produktinnovationen in der Technischen
Logistik. PhD, Helmut-Schmidt-Universität/Universität der Bundeswehr Hamburg,
Hamburg (2006)
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Section 2:
Advanced Application of
Real-time Integrated Building
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Advanced Application of Real-time Integrated Building
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An Enterprise Architecture for Integrating Building Services
1
1
1
1
Apostolos Malatras , Abolghasem (Hamid) Asgari , Timothy Baugé , and Mark Irons
1 Thales Research and Technology (TRT) UK,
Worton Drive, Worton Grange Business Park, Reading RG2 0SB, UK.
{apostolis.malatras, hamid.asgari, timothy.bauge, mark.irons}@thalesgroup.com
Abstract
The realization of advanced services in the building automation domain is hindered by the narrow scope of existing
approaches for the administration of building services. Currently building services are utilized without consideration for
overall coordination and management; they rather have a confined scope, operating in isolation or tightly coupled. This way
of designing building services management architectures is inherently characterized by drawbacks as far as the generation of
advanced, added value services is concerned, while additionally it leads to higher costs and restricts flexibility and
extensibility because of its hardwired nature. We assert that a service-oriented architecture for building services management
that supports the integration of building and enterprise level services will provide numerous benefits, enabling dynamic,
coordinated and distributed building services management. In this paper, we present the design of such an enterprise-based
networking architecture for building services and systems and specify its functional components. We also study relevant
implementation requirements and provide an initial design specification.
Keywords
facilities management, service-oriented architecture, building services, wireless sensor network
1. Introduction
The domain of facilities management can be regarded as the integration of processes within
an organisation to develop and maintain the services that support and improve the
effectiveness of its primary activities [1]. Respectively, building services management refers
to the management of technical building processes, including i.e. HVAC, electricity, lighting,
security systems, etc. Traditional administration of these building services regards them as
having confined scope, operating in a standalone fashion or tightly coupled and providing
minimal support for overall coordination and holistic management, hindering thus the
provisioning of advanced, higher-level services. This approach inherently bears weaknesses
related to complicated management solutions, increased costs and rigid architectural design
that restricts extensibility.
The necessity therefore emerges to adopt a broader perspective regarding the overall
architecture of Building Management Systems (BMSs) that will be open and extensible,
allowing for dynamic integration of novel or advanced building services. Furthermore, the
diversity of the offered building services needs to be addressed, as do the evident scalability
issues subject to the particular building environment application domain. The overall building
services architecture should also realise a long-standing view taking into account the needs of
all stakeholders, which in turn further motivates the need for design flexibility. The notion of
integration signifies the process of connecting services, systems and programs together in a
common architecture so as to share, exchange, and utilise information. The key to the
effective operation of intelligent buildings is not related to the sophistication of the building
services systems; rather it is the integration among the various systems that constitutes the
main driver of success.
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Advanced Application of Real-time Integrated Building
Taking into consideration the above set of requirements, we propose exploiting a serviceoriented architecture (SOA) that will allow for dynamic, coordinated and distributed building
services management. In the case of service-oriented architectures, all entities of the
architecture are decoupled and considered as service providers and consumers. Service
discovery and access to the services are performed in a dynamic manner, ensuring thus a
generic and extensible design. The SOA that we propose exposes all building services on an
enterprise service bus in order for them to be discoverable through service registries.
In addition, we present the overall design of our architecture and specify its components. The
architecture, we propose is compliant with established practices in the building automation
field and is targeted to a wide spectrum of building and enterprise level services. We consider
related implementation issues, so as to promote interoperability and adoption of open
standards. The novelty of our work is based on the application of the state-of-the-art in
enterprise networking for the integration of building management and IT-based services. The
architectural framework we propose assembles all underlying functionality and hides
complexity from the upper-layer applications, by presenting to the building manager a
unifying point of interaction for every operation regarding building services, while allowing
for new service composition supporting novel applications.
The remaining of this paper is structured as follows. After this brief introduction, Section 2
reviews related work in the area of building services and facilities management. Section 3
analyses relevant requirements and serves as the motivation for our work. Section 4 discusses
service-oriented architectures. The enterprise-wide networking architecture for the integration
of building services and enterprise level services is presented in Section 5, while the
specification of the proposed architecture is given in Section 6, taking into account
implementation considerations. Section 7 concludes the paper and discusses open issues.
2. Related work
The notion of providing intelligence in buildings’ operations and enabling autonomic control
and management of the corresponding field of facilities management has attracted significant
research interest over the past decades [2], yet reality has fallen well short of this vision [3].
While successful examples of individual automated building services and systems exist e.g.
HVAC controls, security systems, fire alarms etc., there is an evident lack of holistic,
integrated building management solutions. The need for integration is evident due to the
numerous benefits it can bring to both the occupants of the building as well as the facilities
operators/managers [4].
In typical building automation systems setup, different, proprietary communication protocols
are employed for every product that offers a building service. This hinders interaction
amongst these services, which in certain scenarios is a necessity. Initial solutions to address
this problem included the employment of a hardware gateway that was responsible for the
translation between the non-cooperating protocols [5]. There are apparent drawbacks of this
approach, namely the difficulty in constructing and maintaining the gateways and the lack of
scalability and extensibility, since at least one instance of translation process in a gateway
should exist for every pair of inter-operating protocols.
Efforts to provide more effective and efficient solutions to the interoperability issues led to
the adoption of open, standard protocols to uniform the communication process in all layers
of interaction. Prominent solutions under this category include the BACNet (Building
Automation and Control Network) protocol [6], the LonWorks standard [7], the KNX
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
standard [8], etc. Amongst them, the BACNet protocol has found the wider acceptance by
product manufacturers and researchers in the field. BACNet was developed by ASHRAE and
has been standardised by ANSI and ISO as a communication protocol for building automation
systems. IP compatibility has been developed for the aforementioned protocols allowing for
example BACNet devices to communicate with each other directly using IP. The most recent
development in the realm of building automation systems communication protocols is the
introduction of XML-based Web Services [9] for the integration with other management-level
enterprise systems, e.g. BACNet/WS [10]. This shift has nevertheless not found much
acceptance since its commencement in 2004 [11].
The endeavour to address the integration and interoperation problem has nevertheless not
been achieved with either of the two aforementioned approaches i.e. gateways and standard
communication protocols [14]. It becomes therefore necessary to develop new approaches to
achieve integration of building automation systems and building services at a higher layer,
namely using middleware technologies [12][13]. This trend has emerged over the past few
years and has gained significant attraction from the research community and the industry,
since it is combined to another fact, i.e. the established move towards the convergence of
building management systems and information technology (IT) [15].
Novel integrated building management systems, as the ones proposed in related research work
published for example in [12] [13], do not intend to affect or substitute proprietary, low-level
building automation systems. The focus is on providing smooth integration of diverse systems
and services by using the notion of middleware abstraction, i.e. the individual building
systems continue to operate as originally configured by their manufacturers, yet middleware
wrapper applications are used to make them interact to each other in a unified manner.
Amongst the available middleware technologies, the ones that have been utilised in building
automation environments include OPC [12][13], CORBA [16] and JAVA/RMI [17].
It becomes therefore evident that it would be beneficial to exploit enterprise architectures in
the building management realm. Such an approach promotes IT and building management
convergence, while allowing for the beneficial factors of open, flexible and scalable
enterprise-wide architectures to be gained [18]. Such a research direction has also been
implied by recent work in [12], where there are nevertheless inherent problems mostly
focused on the fact that the proposed solution is based on proprietary, closed technologies
such as COM/DCOM, which hinder interoperability. In addition to that, the work of [12] has
a narrow scope on BACNet enabled devices, while the approach we are considering is more
generic taking into account all IP-enabled devices.
The scope of our work is to provide a reference model for an overall, integrated enterprisewide SOA to address building management issues in a holistic manner.
3. Requirements analysis
The implications of an integration of building and facility management systems into the wider
enterprise functions are far reaching. Commercial buildings require several subsystems to be
manufactured and installed, such as HVAC, lighting, power, safety, and security, which
provide essential services to its occupants. These subsystems must be managed in order to
provide consistent services. Traditionally, the subsystems are operated independently, and at
most, connected together via costly and complicated gateways in order to present a single
interface to the building manager. This means that in most commercial buildings there may be
several complicated, disconnected, and expensive subsystems to manage. This, in turn, affects
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Advanced Application of Real-time Integrated Building
the level of expertise needed to maintain and operate these subsystems. This short discussion
highlights the expected requirements from the various building stakeholders, i.e. occupants,
constructors, managers and operators, as far as the management of modern buildings is
concerned and guides the design of the building-wide enterprise architecture that we envisage.
In recent years, there has been an evolution towards merging these separate subsystems
together with buildings’ IT systems into a single, integrated infrastructure. Essentially, the
integrated system will allow a building manager to control all the different BMS subsystems
using a single interface, a common management protocol, and a common communication
protocol, as observed in [18]. This will allow the avoidance of problems related to
incompatible communication and multiple management protocols, and the need to
interconnect them.
The main drivers behind the convergence of IT and BMSs are to reduce operating cost, reduce
complexity of system, hence training/experience required of staff, reduce capital cost (wiring,
equipment etc.) and to provide value-added services. The main implication of building and IT
systems convergence to our work is that it provides the BMS with access to additional
information that will enable the building to be used more effectively.
This paper describes an enterprise-networking framework that is used for inter-working of
facilities management applications, BMSs, IT and other building related systems including
legacy and novel applications, with other operational enterprise functions in a transparent
manner. The rationale for pursuing this goal is 3-fold:
• Optimize the information flow and accessibility, allowing all authorized systems and
applications, which require a given set of data to have shared access to that data set.
• Increase the coverage, resolution and accuracy of the information awareness made
available to human and automated decision makers, by developing a data web, which all
systems and applications can access and exploit through standard interfaces.
• Develop a new approach to high-level facilities management applications design, allowing
seamless inter-working and forming data composition, context and operational services into
highly added value monitoring and decision making support tools.
In what follows, we first discuss Service Oriented Architectures and then provide a reference
model for the proposed building services management architecture.
4. Service oriented architectures
The enterprise architecture that we envisage, will be based on the Service-Oriented
Architecture paradigm, benefiting from its flexibility, extensibility, open design and support
for interoperability. It conforms fully to the aforementioned requirements and allows for the
desired functionality, as described in the reference model, to be employed. Traditional
computing architectures do not apply well to modern distributed, inter-organizational
computing scenarios, where dynamic membership and changing conditions are the norm.
Interoperability should be ensured, allowing for the integration of diverse platforms and
programming languages. A standardized, flexible, open framework to enable cooperation
amongst diverse entities in the field of application provisioning is necessary. Consequently,
there is an evident need for architectures that satisfy the aforementioned requirements and
criteria and this is the driving force behind the evolution of SOAs.
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SOAs are essentially a means of developing distributed systems, where the participating
components of those systems are exposed as services. A service can be defined [22] as “a
loosely coupled, reusable software component that encapsulates discrete functionality, which
may be distributed and programmatically accessed.” The motivation for constructing a SOA
is to enable new, existing, and legacy pieces of software functionality to be put together in an
ad-hoc manner to rapidly orchestrate new applications in previously unpredicted ways to
solve new problems. This can result in highly adaptive enterprise applications.
It should be noted that the provision of a service is independent of the application using the
service. SOA are supported by standard protocols for service communication and information
exchange i.e. WSDL, UDDI, XML, etc., making services independent of platforms and
programming languages. There are various service models, from JINI, through grid services
and Web Services [11], all of them operating under the same conceptual usage model.
The usage of SOA is as follows (Figure 1). The service provider registers the offered services
to a service registry, which is accessed by a service consumer that wishes to interact with a
service that satisfies certain requirements. The service registry informs the service consumer
on the way to access a service that satisfies its selection criteria, by returning the location of
an appropriate service provider. The service provider and consumer from that point onwards
exchange messages in order to agree upon the semantics and the service description that they
are going to be using. The service provisioning subsequently takes place, with the consumer
possibly expecting some response from the provider at the completion of the process.
Figure 1: Service oriented architectures usage.
5. Enterprise-wide networking architecture for building services
In this section, we present an overall architecture for inter-working and inter-operation of
enterprise applications and services in a seamless fashion. This architecture, as depicted in
Figure 2, is based on a flexible, extensible and open model of integration, following existing
trends, state of the art and developments in the enterprise software arena, based on the Service
Oriented Architecture paradigm. The reusability of services, the decoupling of the service
provisioning from its application use, the design of the service buses and the use of
interoperable information exchange all promote the scalability of SOAs.
The architecture is broken down into a set of enterprise middleware services, a set of
application services and a service bus. These are further described in the following sections.
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5.1 Enterprise middleware services
The middleware services are the integration fabric, which the various service providers and
consumers use. These provide the decoupling facilities, which enable service consumers and
providers to discover each other’s capabilities, without needing any a-priori knowledge of
other platforms. The middleware provides the mediation services, which enable all parts of
the system to dynamically make the best use of any of the existing facilities (access rights
permitted) as they become available. The key functions, which the middleware must provide
fall under three categories:
Service registry/discovery: as it is undesirable to manually provide each component with an apriori knowledge of what other services are available on the enterprise network, an automated
discovery of services must be provided. This must be dynamic, allowing flexibility for
adding, removing or modifying services, as the business requirements evolve. The service
registry block in Figure 2 provides the service discovery functionality.
Service
access
control
Service
registry
Service bus
Building
application
services
Legacy
systems
services
Enterprise
level services
Legacy
system
wrapper
WSN
existing
conventional
BMS
BMS
…
Building
assessment
tools
IT
systems
Ambient
UI
…
Figure 2: Building services architecture reference model.
Service access control: just because service platforms belong to a single enterprise does not
mean they can share all information freely, and that service access rights are universally
granted. Moreover, the cost of providing services internal to the enterprise may require
metering and billing from one department to another. The “Service Access Control” block
therefore coordinates authentication, authorization and accounting (AAA) functions.
Information exchange: the various components of the overall system should be decoupled in
space, time and synchronization. The service bus performs these functions.
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5.2 Application services
This architecture is generic enough allowing for different types of applications to be
integrated, provided they are capable of exposing appropriate services on the service bus. We
identify three special types of applications services, namely enterprise level services, building
application services and legacy systems services.
The enterprise level service category covers all business and operational services, which are
typically available over the enterprise network. Characteristic examples include IT and
security systems, business functions such as accounting, inventory, billing and operational
functions such as e-mail services, personal profile databases, ambient user interfaces to
display building related information, etc. These services are available on software platforms,
which can be directly integrated into the service bus. The services made available by the
application must be advertised to all interested parties, and can be invoked by interested
parties over the service bus.
The building application services build on the services classified as enterprise level and
existing building systems services and utilize their information and functionality to provide
added value services for the building environment itself. Typical examples of this category
could include building management systems and building assessment tools that evaluate
building performance in terms of productivity and energy efficiency.
The reality of most enterprise systems is that they are largely made up of legacy components.
It is therefore essential to provide the means of integrating legacy systems into this
architecture. The “legacy systems service” provides such an integration layer, without
requiring any modification to the legacy systems. A legacy systems wrapper function is
required, which may include hardware as well as software elements to connect legacy systems
to the service bus. The services offered by the legacy systems, adequately translated by the
wrapper, must be advertised, and may be invoked through the service bus. Conventional
BMSs and other existing building services systems such as HVAC can be considered within
the “legacy systems services” scope.
5.3 Service/Communication bus
The service bus enables communication between all the services. The service bus may
provide nothing more than the IP network transport layer services, or be much more complex
in its decoupling of the attached services, for example providing message queuing, semantic
routing, etc. Lately, respective technologies have progressed significantly, i.e. with the
introduction of Enterprise Service Buses, greatly enhancing the offered level of functionality.
6. Specification of proposed architecture
Having asserted the selection of the SOA paradigm for our architecture, we discuss here the
specification issues. As already stated, there exist various service models, such as JINI, grid
services, CORBA, Web Services (WS) etc. We opt in favour of Web Services [11], as Web
Services constitute the major enabler of service-oriented architectures due to the
interoperability that they offer and the fact that they can easily support the integration of
legacy systems. Their wide-acceptance and the fact that they allow for easy and
straightforward deployment of applications over enterprise networks and the Internet in
general, make them most suitable for the proposed architecture. WS constitute a means for
various software platforms to interoperate, without any prerequisite regarding platforms and
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frameworks homogeneity being necessary. The services described in the proposed reference
model will be hence implemented using WS technology.
XML is the standard technology used by WS for exchanging business documents. The
structure of business documents is formally defined in terms of XML type definitions using
XML Schema Definitions. There are two types of WS, namely SOAP-based and REST-based.
SOAP [23] based services are the WS that have received the more attention. Other systems
interact with the WS in a manner prescribed by its description using SOAP messages,
typically conveyed using HTTP with an XML serialization in conjunction with other Webrelated standards. A SOAP-based service expects to receive requests as an XML document
wrapped inside the body of a SOAP envelope. Additional application specific information
may optionally be carried in the SOAP header. This may include security information and
message routing information. The service response is also wrapped in a SOAP envelope.
REST is an acronym for REpresentational State Transfer [21]. The term is derived from the
notion that clients use a unique URI to retrieve a representation of a resource, which causes a
transfer of state to occur in the client, e.g. a client wishing to retrieve a representation of the
current temperature in a particular room of a building could use the following URI:
http://my.smart.building/room101/temperature. WS based on REST are simpler alternatives to
the complexity of SOAP-based WS and appear to be gaining popularity. A REST-based WS
is not accessed via a request packaged inside a SOAP message, but directly using the HTTP
GET method to a URI such as the example given above. The response is usually in the form
of a raw XML document directly over HTTP without using SOAP.
We exploit an Enterprise Service Bus (ESB) that takes care of interoperation issues assuming
the role of the service bus of the aforementioned enterprise networking architecture. An ESB
provides a software infrastructure that simplifies the integration and flexible reuse of
components within a SOA by supporting any-to-any data connectivity and transformation. An
ESB is message-oriented, service oriented and event driven, and these characteristics combine
to deliver a scalable and dependable infrastructure capable of integrating disparate
applications and IT resources. For example, the ESB can interconnect Web Services built on
JEE and .NET platforms to legacy applications and legacy middleware components.
The ESB is capable of performing transformations of communications protocols, data
formats, and interaction patterns to achieve interoperability between software components that
would otherwise be incompatible. This results in loosely coupled systems that can inter-work,
be modified and extended with minimal disruption. ESBs are standards based, usually relying
on XML as the universal data model, and HTTP as the generic, application-level protocol for
information exchange. The high level architecture of a typical ESB system is shown in Figure
3. There is an evident matching to the architecture of Figure 2, the services of which can be
implemented using any of the diverse, available service models, while their integration
remains part of the ESB functionality.
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Figure 3: Enterprise Service Bus.
As far as specific development technologies are concerned, it has to be stated that there exists
a big number of available choices. Having reviewed most of these we have chosen to exploit
open-source solutions, to allow for dynamic, low-cost, reliable implementation of the desired
functionality. One of the most popular open source tools for providing and consuming WS is
Apache Axis2 [19], hence we use this for implementation. It is a Java implementation of both
the client and server sides of the WS equation, while supporting the full-fledged set of WS
expected functionality. In addition to that, Apache Synapse [20] is an open source WS
mediation engine, i.e. ESB, which is built on Apache Axis2. Synapse provides support in the
areas of connecting services, management and data transformation, providing for example
translation mechanisms between SOAP- and REST-based WS.
Our future work focuses on using the technologies that have been identified above for
implementation and evaluation of the proposed architecture for seamless management of
building services.
7. Conclusion
The focal point of this paper is the overall integration architecture, which provides the
flexibility to support the vision of convergence of building and IT services. This architecture
draws on the state-of-the-art and ongoing architectural evolution of enterprise networks,
which are actively striving to develop open and standard ways of connecting traditionally
independent systems in a dynamic and flexible way.
Hence, this paper proposed and specified a Service Oriented Architecture as a new approach
in developing an enterprise networking environment that is used for integrating facilities
management applications and building management systems with other operational enterprise
functions for the purpose of information sharing and monitoring, controlling, and managing
the enterprise environment.
Our future work includes the implementation of the proposed architecture employing
identified technologies. A use-case scenario will be considered focusing on the integration of
WSNs with the enterprise architecture. This use case scenario will be deployed, evaluated and
tested in our experimental testbed. It will serve as a proof-of-concept of the envisaged SOA.
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The benefits that can be reached by utilizing service-oriented enterprise architectures are
numerous; hence the need to move towards such approaches can be realized. Any move
towards such an approach has to consider all relevant aspects in order to provide an efficient,
integrated service oriented architecture for building management.
It has to be stated that it is the responsibility of the manufacturers of existing applications for
building services management to create and expose appropriate service interfaces in order to
allow for the existing systems to be smoothly migrated to SOA-enabled environment.
Acknowledgments. Work towards this paper was partially supported by the Commission of
the European Union NMP I3CON FP6 project, NMP 026771-2.
References
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intelligent building systems based on the sub-system peer mode, IMACS Multiconference
on Computational Engineering in Systems Applications, IEEE, pp. 1766-1770, October
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14. Frost and Sullivan Report, North American building automation protocol analysis, A14319, May 2002
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15. Ehrlich, P., Guideline for XML/Web Services for building control, Proceedings of
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17. Davidsson, P. and Boman, M., Distributed monitoring and control of office buildings by
embedded agents, Information Sciences - Informatics and Computer Science: An
International Journal, Vol. 171, No. 4, pp. 293-307, Elsevier, 2005
18. Maile, T., Fischer, M. and Huijbregts, R., The vision of integrated IP-based building
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19. Apache Axis2, http://ws.apache.org/axis2/, accessed September 2007
20. Apache Synapse, http://ws.apache.org/synapse/, accessed September 2007
21. Fielding R T, Architectural Styles and the Design of Network-based Software
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(REST),
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The I3CON Service Engineering Approach
- A Modular Approach for Developing
new Construction Services
Lesya Bilan1, Liza Wohlfart1, Iris Karvonen2
1 Fraunhofer IAO/ University of Stuttgart IAT, Competence Centre R&D-Management,
Nobelstrasse 12, 70569 Stuttgart, Germany
{Lesya.Bilan, Liza.Wohlfart}@iao.fhg.de
2 VTT Technical Research Centre of Finland
P.O. Box 1000, FI-02044 VTT
[email protected]
Abstract
The service industry is Europe’s most important industry sector. Services are no longer a by-product of products; they are an
essential part of the solution package offered to the customer. This trend also affects more traditional sectors, such as
construction, who thus feel an increasing need for approaches on how to successfully develop new service concepts. This
paper presents the modular Service Engineering approach developed in the EU-funded project I3CON that specifically
focuses on the construction industry.
Keywords
Service Engineering, collaborative Service Engineering, value-driven services, product service, construction industry
1
Introduction
European construction companies today face the global challenges of our time – complexity,
speed, flexibility, globalisation. In order to stay competitive, excellent products are no longer
enough. It is more and more product services combinations that frame tomorrow’s businesses.
The service sector is the key aspect of future European markets, as a newsletter of the
European Commission says. “They are not only the largest industry sector in the EU economy
today, it is also the most fast-growing one” [2]. Services no longer are a nice add-on for
existing products – they are part of an overall solution package offered to the customer. And
they can initiate innovation – especially in traditional industry sectors such as construction.
“Knowledge-intensive services such as market research, engineering and technical services or
design […] also gain importance as generators of innovations that affect the whole industry,
especially with respect to traditional production branches” [2].
As it is more and more services that guide tomorrow’s industries, there is an increasing need
for concepts to support the successful development of new service models. One of these
concepts is Service Engineering, an approach that helps companies to design and develop new
and existing services/ service models in a structured, modular step-by-step way.
The EU-funded project I3CON (Industrialised, integrated, Intelligent Construction) currently
develops a structured, modular Service Engineering concept that specifically fits the needs of
construction services – in supporting the services along the life cycle of buildings.
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2
Definition of (product) services
2.1 Services vs. physical products
According to Kotler & Bloom, "a service is an activity or benefit that one party can offer to
another that is essentially intangible and does not result in the ownership of anything. Its
production may or may not be tied to a physical product" [8]. This and numerous other
definitions of services (for instance those of Grönroos [3], Simon [14]) coincide in naming the
main features of services: their intangibility and their nature of activities rather than things
(material objects), though the production of services may but should not be tied to a physical
product.
These characteristics of services account for the fact that many service providing enterprises
face the problem concerning the systematic design and creation of service portfolio. Thus, the
growing spectrum of services that can be offered and the increasing complexity of these
services exercise negative influence on their quality as well as on the costs structure. Related
to this, a further problem occurs: the insufficient conception of services, which leads to their
inefficient performance in practice.
Another feature of services is that they are produced and consumed simultaneously (at least to
some extent), making it difficult or even impossible to store them, which on the other hand
lets customers participate in the production process. One of the definitions of services
describes them as “[activities] or series of activities of more or less intangible nature that
normally, but not necessarily, take place in interactions between the customer and service
employees and/or physical resources or goods and/or systems of the service provider, which
are provided as solutions to customer problems” [3]. These numerous interfaces within a
service are the reason for the problems experienced by service providers. At the same time
these interfaces offer numerous possibilities for value derivation and value creation.
In the concept of Thoben [15] a traditional physical product is introduced as an “extended
product”. In this concept a traditional physical product is extended with an intangible part, for
example with information, service, or other benefits. According to Thoben [15], services are a
special case of extended products, which in their turn may be complemented with further
intangible components.
Tukker and Tischner introduced a notion of “product services” which are services that are
linked to a specific physical product. “The Product Service (PS): a mix of tangible products
and intangible services designed and combined so that they are jointly capable of integrated,
final customer needs” [16]. Product services may be offered to the customer as services along
the life cycle of a physical product. These services typically include a wide range of potential
services, for example maintenance of a product or its operation without actual ownership of
this particular physical product.
The I3CON project focuses on building life cycle services, including facility management
services. These services are linked to a specific physical product. Based on the terminology
and definitions introduced above, the services developed within I3CON are considered
product services, whereas the product is the building and customers derive value by using the
building. This means that not only separate (living) premises are offered as a physical product
but the whole (living) environment, e.g. neighbourhood integration, in a word, services along
the life cycle of a physical product. Thus the demand for service quality becomes at least as
high as the demand for product quality, and the housing industry becomes more customer-
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oriented and tends to offer more living-accompanying services which focus on individual
requirements of customers.
2.2 Product services within the I3CON project
Grönroos [3] identified the following service features:
•
their intangibility;
•
their nature of activities rather than things;
•
simultaneity of service production and consumption, at least to some extent;
•
the necessity of customer participation in the production process.
These are the main features differing services from physical products. For physical products it
is easily possible to provide product models, drawings, prototypes, to visualise products,
while it is difficult to provide a comprehensive description of service content and service
model, to specify the activities required for providing a service, and to create a business
model for a separate service.
Speaking about “product services” as a group of services, Tukker & Tischner [16] classify
product services into three main categories (Figure 1):
1. Product-oriented services: for this category of services, business model is still
dominantly geared towards sales of products, but some extra services are added;
2. Use-oriented services: for these services the traditional product plays a central role, but
business model is not anymore geared towards selling products. The product stays in the
ownership of the provider and is available in a different form and sometimes shared by a
number of users;
3. Result-oriented services: for this category of product services, the client and provider in
principle agree on a result, and no pre-determined product is involved.
Fig. 8. Categories of product services [16]
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In our project, in which a building is the product, these categories are considered as different
levels of value-driven building life cycle services. For the building as a product, all product
service categories listed above are available. Thus,
1. for product (building)-oriented services the building is in the ownership of the customer,
but some extra services giving value to the customer are established;
2. for use-oriented services the building is in the ownership of the service provider and
customers get value by using the building;
3. for result-oriented services no pre-determined building is necessarily involved, but the
value for the customers is the main starting point for the service implementation.
Mont [11] points out that the product-service systems also challenge the understanding of
producers’ and consumers’ role. Traditionally, producers are seen as creators of value,
whereas customers are seen as value destroyers. In the service industry (or functional
economy) producers become providers of value, whereas customers become users of value.
Even more, there often is a joint value production by the producer and the customer. The
ownership may reside with the producer or retailer of the product. Also, the buyer cannot
return the service in case of dissatisfaction. In some cases (but not always) the provider can
recreate the service.
3
Challenges of services in today’s market
The characteristic features of the services described above are the reason why it is often
difficult to prove the value of a service to the customer. The difficulty to attract customers to
service solutions has been identified by several authors (Mont [11], Oliva & Kallenberg [12]).
Thus Mont [11] states that one of the reasons for the low interest (potential) customers pay to
industrial services is the missing knowledge of life cycle costs. Consequently, prices of
services seem to be high. For example, condition monitoring service does not as such add
value to the customer; only if a higher availability is offered, the end-user is able to quantify
the value of the offering [12]. On the other hand, the provision of life cycle services may
require unpredictable risks from the service provider, and thus affects the service pricing, too.
Another problem is the vagueness of the service contents, due to which the provided value
and the quality are not quite clear, as well as the service provider and the customer actions
which are not strictly defined. This unclarity of the service offering also contributes to the
ineffectiveness of the service design and delivery and finds its reflection in service pricing.
Speaking about the challenges of service providing, the whole life cycle of a service product
needs to be taken into account: from identification and concept to design, implementation,
operation, and dissolution.
Before proceeding with requirements of the service market and solutions to numerous
problems in this field, it should be stressed that the major challenge is to analyse and
understand the service entity and specifically what is being offered to the customer, what
actions and functions are included, how to describe the links to a physical product, whether it
can be specified into components, what resources are required, and how to define service
quality.
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3.1 Contradictory requirements in today’s service markets
Contemporary trends in the economy show the growing importance of service performance as
means to differentiate a company from its competitors. At the same time there is a strong
trend towards outsourcing industrial services which also leads to the increasing demand for
services. This trend is further strengthened by certain social developments which show
increasing need for leisure, entertainment, life quality, and care services. In a word, the
meaning of services for the customers (consumers and users) is growing.
At the same time another tendency can be observed: the focus shifts to the core competences
on the part of the providers. The competition pressure forces many enterprises in different
branches to concentrate on their few core competences and to rather outsource their secondary
competences. In many cases this in fact lets companies provide cheaper services. Companies
that have their competencies combined belong to highly integrated, usually very young
branches. At the same the narrowing spectrum of services can be observed in traditional
industrial sectors, e.g. automotive industry, where many services/competences are being
outsourced. Thus, there is a discrepancy between the concentration on core competences and
the requirement for complete solutions (software solutions, facility management), i.e. fullservice solutions which can be provided individually, from one window, as customers wish.
The following is an overview on key challenges service providers have to cope with today:
• Enhanced customer orientation: Services emerge as a result of the contact with the
customers. This makes them very individual. Considering this fact as well as the trend to
reorientation from provider to customer market, individual customised solutions have good
chances to reach high degree of acceptance and assure return of costs over time.
• Tense price competition: The challenge of customer orientation is closely connected
with the price competition in most service branches. Modern information technology made
the direct price comparison possible and available for each customer. Price is very often seen
as a quality indicator, though at the same time it plays an important role in perchance
decisions (when customers decide if they order a service or not, or if they go for a service
offered by a competitor).
• Optimisation and standardisation: Cost consideration in order to reach high customer
acceptance becomes decisive in price competition on the market. That is why it is so desirable
and attractive to gain standardisation possibilities as early as in the development phase. At the
same time, optimisation possibilities should be checked for each process step. This requires
close contact to the customer who should also be involved in the development and design of
services.
• High innovation rate: Technical changes which take place especially fast in the fields of
information and communication technologies demand a high innovation rate from the
supplier/provider. New services/service packages can solve customers’ complex problems and
satisfy the emerging new requirements and thus ensure the compatibility of a company. The
shrinking life cycle of services demands the application of new, mostly knowledge intensive
services and the shortening of time-to-market.
• High quality requirements: The practice shows that shortcomings in the quality of
services are much less tolerated than any defects of material products. Thus, high quality
guarantee is a critical success factor for a service provider. The complex task of finding the
most satisfactory solution for the customer, demands from the supplier not only total process
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Advanced Application of Real-time Integrated Building
control but motivated employees as well, characterised by good social and emotional
competences.
• Excellent delivery competence: As already mentioned, one of the characteristics of
services is that they are produced and consumed simultaneously, i.e. they cannot be stored.
Considering that services are normally provided people-intensively, employees give a supplier
the necessary potential to provide a service. At the same time a good ability to deliver a
service requires as a rule high personnel costs. Thus for example, long queue time for a
hotline or a call-centre can result in customer dissatisfaction and in some cases can lead to
negative influence on the compatibility of a company.
• Demand for package service: Such concepts as system or modular sourcing are applied
in the producing branches. They can provide an example for “package service” (full-service
supply) which substitutes single services. Customers demand complete problem solutions,
acquired from a single service provider, so to say “at one counter”. Due to the availability of
package services, coordination and acquisition costs can be reduced or even omitted, thus
leading to the overall costs reduction and quality improvement. Customer’s willingness to pay
can be increased.
3.2 A way to respond to the market pressure: collaborative Service Engineering
The challenges listed above increase the performance pressure on service providers. The
development of new strategies and search for new alternatives are the ways to solve the
emerging problems. Collaborative Service Engineering is an integrated approach to the
systemic service development and creation and design of service processes. The method of
Service Engineering, applied in collaborative networks, enables the creating of attractive
service packages within these networks. Possible collaboration partners are customers, service
providers, consulting companies, product suppliers. The intensity of their cooperation should
not be same in all phases of the development process – it depends on the needs of partners and
on process requirements.
In a network, partners can face the challenges together and at the same time each
collaborating partner can preserve his specific advantages (flexibility, specialisation), thus
staying independent. This enables small and medium-sized servicing enterprises to compete
even with big companies. Successful networks create a win-win situation for all partners.
Under such circumstances a question comes up why only few service providers make use of
the advantages offered by networking. Some reasons are the lack of knowledge and method
deficiency, especially on the part of small and medium-sized service providers who
particularly need support and strategic orientation. A comprehensive cooperation management
can support them in the realisation of their cooperation plans by means of enhancing their
cooperation ability and skills and also those of their potential partners.
4
Service development
Considering the important role of customers in service development, making service
performance and consume extremely individual compared to industrial products, it is still
possible and even reasonable to systemise the process of service development, from the
service idea through its planning to the actual performance and to support it by different
methods. This would let the service provider reach high quality and efficiency which is
reflected in customer satisfaction and high acceptance of the offered services and their easy
implementation.
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Good planning and development have to provide a solid basis for high quality services.
Service Engineering applies a systemic approach to the creation and development of (new)
services. It conceives the creative process of service development as a system, a successive
and comprehensive process, targeted at a certain objective. This approach, balancing between
creativity and system, can push innovation in the service area with respect to quality, time,
and costs.
4.1 Existing Service Engineering concepts
The I3CON Service Engineering approach builds on the Fraunhofer IAO modular concept for
Service Engineering. According to this concept, the Service Engineering process can be split
into six consecutive phases: definition phase, requirements analysis, service concept, service
realisation, market launch preparation, and market introduction. The phases are interrelated
and are either a logical consequence from the preceding phase or a necessary source for the
subsequent one, though the concept of Service Engineering presupposes simultaneous work in
different phases.
Definition
phase
Requirements
analysis
Service
concept
Service
realisation
Market launch
preparation
Market
introduction
Fig. 2. The Fraunhofer IAO Service Engineering concept: Service Engineering phases 10 [10]
Each phase is represented by a number of elements, so called steps that can be deliberately
combined with steps from other phases. They thus present a kind of Service Engineering
chain consisting of steps from different phases. Each step comprises three elements: activities
(What has to be done within the step?), methods (How is it done?) and roles (Who has to be
involved?). It depends on each individual service under development, which steps and which
single points in each step are applied in the development process. Instead of sequential
processing of each phase, the focus is rather on separate steps within each phase.
Another important input to the I3CON approach is provided by the construction Service
Engineering concept of the Bundesverband deutscher Wohnungsunternehmen (GdW) [6].
Similarly to the Fraunhofer IAO Service Engineering concept, the GdW model presents
various tools to be used along different engineering phases. There are, however, some aspects
which differentiate both approaches:
1. The GdW model has less engineering phases, which simplifies the concept.
2. The GdW model classifies tools according to two categories: tools for content creation and
tools for content assessment.
3. The GdW provides checklists to each phase.
10
Legend:
deliberately.
The boxes with different colours mean separate steps in service engineering. The colours were selected
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Advanced Application of Real-time Integrated Building
4.2 The I3CON approach for Service Engineering in the construction sector
The I3CON Service Engineering approach will build on four main phases, each comprising
different steps (as realised in the Fraunhofer IAO method). The image below presents a
working draft of the I3CON Service Engineering approach.
Fig. 3. The I3CON Service Engineering approach
5
Conclusions and next steps
The previous chapters have presented an approach for the systematic development of new
construction services, as developed in the I3CON project. The current prototype consists of
four phases. Each phase contains several steps, each supported by a set of different tools. This
architecture increases the flexibility of the approach, while it at the same time ensures a
structured step-by-step process guiding companies in the development of new services.
The work on the I3CON Service Engineering approach is progressing. In the next weeks the
focus will be on adapting the Fraunhofer IAO concept and the GdW model, which are the
basis for the I3CON approach, to the specific needs of the construction industry.
The final version of the I3CON Service Engineering approach will make it possible for
service providing enterprises to find possible ways of answering the questions below:
•
How can a win-win service model for the customer and the service provider be created?
•
How can the production of services (service products) be enhanced?
•
Is it possible to create new engineering practices for developments of services?
• Considering that services are often related to a physical product, how is it possible to
integrate the engineering of a service into the engineering of the physical product?
• How can the knowledge/information about service products be stored, exchanged,
managed and protected?
At the moment the developed approach is tested and evaluated by the industrial enterprises
within the I3CON consortium. Initial tests have provided valuable insights for the further
adaptation of this concept to the needs of construction companies and to the objectives of the
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I3CON project. The tests of the coming weeks will help to further improve the concept. The
first applicable prototype of the I3CON construction Service Engineering concept will be
available in May 2008.
References
1. Böhmann, T. and Krcmar, H.: Modulare Servicearchitekturen. In: H.-J. Bullinger and A.W. Scheer (eds.). Service Engineering. Entwicklung und Gestaltung innovativer
Dienstleistungen. Berlin, Heidelberg, New York: Springer Verlag (2003) 391-415
2. Europäische Kommission: Innovations-Newsletter der GD Unternehmen der Europäischen
Kommission. Dossier Innovation in Dienstleistungen. „Allein auf weiter Flur?“.
http://cordis.europa.eu/itt/itt-de/04-4/dossier01.htm
(online
document,
accessed
10.01.2008)
3. Grönroos, C.: Service Management and marketing, Lexington Books, San Fransisco (1990)
4. Gruhler, W.: Gesamtwirtschaftliche Bedeutung und einzelwirtschaftlicher Stellenwert
industrieller Dienstleistungen. In: H. Simon (ed.) Industrielle Dienstleistungen. Stuttgart:
Schäffer-Poeschel Verlag (1993) 23-40
5. Hartel, I.: Virtual Organization of After-Sales Service in the One-Of-A-Kind Industry. In
Camarinha-Matos, L. (edit.) Collaborative Business Ecosystems and Virtual Enterprises,
IFIP TC5/WG5.5 Third Working Conference on Infrastructures for Virtual Enterprises
(PRO-VE'02), May 1-3, 2002, Sesimbra, Portugal (2002)
6. Hohm et al.: Innovative Dienstleistungen "rund um das Wohnen" professionell entwickeln.
Service Engineering in der Wohnungswirtschaft. GdW Bundesverband deutscher
Wohnungsunternehmen e.V. Berlin (2004)
7. Kersten, W., Kern, E.-M. and Zink, T.: Collaborative Service Engineering. In: H.-J.
Bullinger and A.-W. Scheer (eds.): Service Engineering. Entwicklung und Gestaltung
innovativer Dienstleistungen. Berlin, Heidelberg, New York: Springer Verlag (2003) 351370
8. Kotler, P., Bloom, P.N.: Marketing Professional Services, Englewoods Cliffs, PrenticeHall, New Jersey (1984)
9. Levitt T.: Marketing intangible products and product intangibles, 'Harvard Business
Review'
(May--June
1981)
http://futureobservatory.dyndns.org/9430.htm#Product_or_Service (online document,
accessed 06.06.2007)
10. Meiren, T.: Entwicklung der Dienstleistungen unter besonderer Berücksichtigung der
Human Resources; in: Bullinger, H.-J.: Entwicklung und Gestaltung innovativer
Dienstleistungen, Tagungsband zu Service Engineering 2001, (IAO), Stuttgart (2001)
11. Mont, O.: Product-service systems: Panacea or myth? Doctoral Dissertation, Lund
University, Sweden, (September 2004)
12. Oliva, R., Kallenberg, R.: Managing the transition from products to services, International
Journal of Service Industry Management Vol. 14, No 2, 2003, 160-172
13. Schneider, K., Wagner, D. and Behrens, H. 2003. Vorgehensmodelle zum Service
Engineering. In: H.-J. Bullinger and A.-W. Scheer (eds.). Service Engineering.
Entwicklung und Gestaltung innovativer Dienstleistungen. Berlin, Heidelberg, New York:
Springer Verlag (2003) 117-141
14. Simon, H.: Industrielle Dienstleistung und Wettbewerbsstrategie. In: H. Simon (ed.)
Industrielle Dienstleistungen. Stuttgart: Schäffer-Poeschel Verlag, (1993) 3-22
15. Thoben, K.-D.; Eschenbächer, J. 2003. Emerging concepts in E-business and Extended
Products (Gasós, J.; Thoben, K.D.: E-Business Applications. Springer-Verlag (2003) 266
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Advanced Application of Real-time Integrated Building
16. Tukker, A. and Tischner, U. (eds.) 2004. New business for old Europe. Product-service
development as a means to enhance competitiveness and eco-efficiency. Final report of
suspronet. http://www.suspronet.org/ (online document, accessed 07.06.2007)
140
The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Real Time Building Information Service for Emergency
Management
Kalevi Piira1, and Veijo Lappalainen1
1 VTT Technical Research Center of Finland
{Kalevi.Piira, Veijo.Lappalainen}@vtt.fi
Abstract
Paper describes a new advanced emergency management support system, which produces focused real time information into
the rescue vehicle about the building in fire. The support system combines the location based real time information about fire
and building technical systems like fiery spaces, ventilation system’s status, activated loops of the fire-extinguishing system
and smoke control system etc. with static information of FM like real estate’s layout, floor plans, location and effect areas of
systems/equipments, spaces of dangerous substances, valuable spaces, fire sections etc. and reports it to different kind of end
users. The context aware system supports different end user groups like fireman, local control room operator and the
personnel occupying the building etc. Reporting to local users is based on the broadband data communication. The support
system introduced in this paper is presently in test use in several big buildings in Finland.
Keywords
life safety, fire, emergency management, integration, building information system, BIM, building automation and control
system, building management system, building services
1
Introduction
In big buildings like shopping centers, hospitals, hotels, big office buildings, industrial areas
and public underground spaces the overall building services system can include many
different technical systems like building automation system, HVAC, fire detection, smoke
control, sprinkler, access control, CCTV, lifts, etc. Typically their product and operative
information are managed through up-to-date building information systems like Facilities
Management systems (FM). In emergency situation like fire the rescue personnel can’t
however get relevant context related information about these buildings (spreading and
propagation of fire, status of building’s technical systems, locations of dangerous materials
and valuable objects, critical spaces for company’s businesses, etc.).
This paper is based on the research results achieved by VTT in collaborative PARK 11 project
[1] carried out in 2003-2007 in Finland. The objectives of PARK project were as follows:
To study how to combine the location based real time information about fire and
building technical systems (BACS, fire detection etc.) with static information of BIM
(building information model), existing CAD pictures and aerial photo.
-
To study how to report it to different end user groups.
To develop a new ICT based prototype to report that information for different use
cases like fire officer in moving rescue vehicle going to lead the fire fighting and personnel
inside the burning building.
11
PARK is the Finnish acronym for Building Reporting to Rescue Vehicle
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Advanced Application of Real-time Integrated Building
The main approach was to use as much as possible existing building automation standards and
standard based open technologies and integrate those existing “Lego blocks” using modern
Internet software integration technologies called web services.
2
Research challenges
The first challenge was to find out what information from building and its technical system is
needed most in fire incident. The information needed about burning building was studied
interviewing eight fire officers in different parts of Finland. Interviews consisted predefined
and open questions and the time frame of a interview was in average two hours. The
interviews were performed in 2003. The predefined questions were related to the information
needed from spaces, structures, technical systems, dangerous materials, application usability,
manner of representation (graphics etc.) and information needed in different situations
(approach, first 10 minutes, after first 10 minutes, for archive). Open questions were for
example like “what information the leader of fire fighters does really need in the case of fire”.
The results of the interview survey are presented in conference paper [2]. The results of the
interviews were utilized later on when directing the development work of the new ICT
prototype for emergency (fire) management support.
The main challenge was to find out the modern ICT solution (integration, data transfer and
implementation technologies) to combine data from building’s real time systems (automatic
fire alarm, building automation, HVAC, automatic fire extinction, smoke abatement,
motorized fire damper and other fire protection systems, safety and secure, access control,
lifts, CCTV etc.), always up-to-date building facility management database information,
maintained CAD pictures (layout, floor plans) and air photo and send it using wireless data
transfer to the moving rescue car. The main approach was to use as much as possible existing
building automation standards and standard based open technologies and integrate those
existing “Lego blocks” using SOA based architecture and related Internet software integration
technologies i.e. Web services [3].
3
Results
The fist prototype of emergency management support system was developed for fire officers
[1]. General overview of fire related case is shown in Fig. 1.
On the other hand there are many other user groups who need more information of
emergency. A more general concept of emergency management support system is shown in
Fig. 2. The idea was to develop context aware system (based on fire officer system) that
support different end user groups like fireman, local control room operator and the personnel
occupying the building etc (Fig. 2).
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Fire incident
Fire alarm system
REAL ESTATE
EMERGENCY CENTER
Automatic fire alarm
RESCUE CENTER
User Interface
3. Floor
Building object info
Fire
starting place
How to minimaze fire
damages
Building Automation System
Automatic Fire Extinction System
Spaces on fire
• For people
• For Building
Attact routes
• Direct damages (fire)
Laptop Computer
Dangerous
substances
• Indirec damages
(water, smoke)
with
PARK
Fire
• For
Business
Electric power centers
Safety Tools's
User Interface
Smoke Control System
Real time data etc.
Access Control System, etc.
Building
information
FM System
Fire Safety
Application
Fig. 1. Overview of emergency management support system for authorities.
SERVER
MODULES
REAL ESTATE
BUILDING TECHNICAL
SYSTEMS
DEVIATION IN
BUILDING SAFETY
SITUATION
Automatic fire alarm system
Building automation system
Automatic fire extinction system
Smoke abatement system
Motorized damper and other fire
protection systems
Facility management systems
BUILDING
DATABASE
CLIENT MODULES
Emergency
mgt. system for
authorities
SECURITY
DATABASE
Automatic fire
alarm
DATA FOR RESCUE
AUTHORITIES IS GATHERED
IN ONE DATABASE
Re-directed
alarm
On-site
disaster mgt.
system
Real-time
reporting in
disaster
situation
Authorities
Security Company
Control Room
Staff and Customers
Safety Management
SECURITY
DATABASE
Delivery of building
data once a week
LOCAL SEURITY
DATABASE ON-SITE
Testing and Maintenance
Training
Fig. 2. Overview of emergency management support system for different interest groups.
One of the most important decisions was the selection of the information system architecture
for the emergency management support system. SOA based architecture and Web services
was selected because there are many different types of systems that had to be integrated (Fig.
3).
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Advanced Application of Real-time Integrated Building
Emergency management applications
for different user groups
Emergency related information services
Facility management
systems (BIM)
Building technical
systems (BACS etc.)
Fig. 3. Emergency management system architecture.
Service oriented architecture (SOA) is a paradigm for organizing and utilizing distributed
capabilities that may be under the control of different ownership domains. Unlike object
oriented programming paradigms, where the focus is on packaging data with operations, the
central focus of SOA is the task or business function getting something done. [4]
The selection of SOA based architecture and Web services are compromise. Web services are
platform independent, specifications are based on existing standards, the programming and
integration of different loosely coupled components and services which are decentralized over
Internet is easy. On the other hand Web services are not the most efficient way from data
transfer point of view.
On the other hand there have been a number of activities related to BIM and BACS
standardization. These activities were studied but the final solution was made by developing
open but not standardized BIM for emergency case. Studied BACS interfaces were LonWorks
[5], OPC [6] and Alerta [7], [8], [9]. LonWorks is official BACS standard, OPC is de facto
standard mainly used in industrial automation and Alerta is a teleoperator’s secure data
transfer solution for public authorities (for example emergency center) and building sector
companies. Alerta support most of proprietary BACS and automatic fire alarm systems
available in Finland.
Teleoperator’s secure data transfer solution based concept is shown in Fig. 4 and OPC based
concept in Fig. 5.
The communication is based on the broadband data communication supported by short
message service (SMS) based text messages. For the authority version wireless data
communication like 3G, EDGE, GPRS, OFMD and WLAN data transfer was tested.
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Facility management
server
Automatic replication
Rescue tender
Local PARK™
database
Local PARK™
server
INTRANET
PARK™ server
for public authority
INTERNET
Park-Alerta
listener
PARK™ clients
(+ PARK™ alarm listeners)
Firewall
Automatic fire extinguishing system
Air conditioning, Motorized fire vents, smoke control, lifts, jne.
PARK™ database
for public authority
Automatic replication
Park-Alerta
listener
ALERTA
TERMINAL
alarms
PARK™ personnel
ALERTA
ALERTA
alarm
alarmnetwork
networkfor
for
public
publicauthority
authority
PARK™ control room
alarms
PARK™ safety management
IP
PARK™ xxx
Automatic fire alarm system
ALERTA adapter card
RS485
alarms
ALERTA
TERMINAL
IP or SMS
ADSL
Building automation system
Fig. 4. Teleoperator’s secure data transfer solution (Alerta) based concept of building emergency managements
system.
Facility management
server
Automatic replication
Local PARK™
database
Local PARK™
server
INTRANET
PARK™ clients
(+ PARK™ alarm listeners)
Firewall
Automatic fire extinguishing system
Air conditioning, motorized fire vents, smoke control, lifts, jne.
Rescue tender
Automatic replication
INTERNET
PARK™ control room
OPC
server
PARK™ safety management
PARK™ xxx
Building automation system
PARK™
server
for public
authority
alarms
PARK™ personnel
Automatic fire alarm system
PARK™
database
for public
authority
alarms
alarms
IP
Park-OPC
listener
Fig. 5. OPC de facto standard based concept of building emergency managements system.
The main result of this study was a new prototype for emergency management.
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Advanced Application of Real-time Integrated Building
4
Prototype
A new advanced ICT support system has been developed, which reports (displays) focused
real time information into the moving rescue vehicle in the case of fire using wireless data
transfer. The support system combines the location based real time information about fire and
building technical systems like fiery spaces, ventilation system’s status, activated loops of the
fire-extinguishing system and smoke control system etc. with static information of FM like
real estate’s layout, floor plans, location and effect areas of systems/equipments, spaces of
dangerous substances, valuable spaces, fire sections etc. and reports it to different kind of end
users. The context aware system supports different end user groups like fireman, local control
room operator and the personnel occupying the building etc.
“Layout” function of the emergency management prototype is presented in Fig. 6. The main
idea was to integrate real time information of fire and BACS and the facility management
information (BIM) of the location of fire detectors and show it by means of CAD
technologies. In this example the part of the building which is on fire is blinking red in the
layout picture. Other information included in the prototype are attach routes for fire fighters,
rescue ways and the locations of main valves, switches and building technical system centers
and aerial photo of the site.
Web services based
integration of
CAD picture
Aerial photo
Real time
information of fire
BIM data
and wireless data
transfer into the
moving rescue car
Fig. 6. “Layout” function of the emergency management prototype application.
Next example describes how emergency management prototype utilizes the integrated
information from different sources. Function “Fire initiation place” combine the exact place
where the fire has started with space information from facility management system and show
the result in floor planes. Information included in the prototype are fire sections and how near
the fire are to dangerous materials (risks for fire fighters) and valuable spaces for business of
the company working in the building. Fire initiation place is colored red and other selected
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
information is green. These and other features of the prototype are described more detailed in
conference paper [1].
5
Further development
Emergency management extension for city flood is under development. It is not ready but the
main idea is to utilize local rain information (Helsinki testbed and sensor networks),
measurements of network flow (sensor networks), surface modes of test areas (based on lidar
analysis) and existing emergency management prototype.
6
Conclusions
In this paper a new advanced support system, which reports (displays) focused real time
information into the moving rescue vehicle in the case of fire using wireless data transfer is
presented. The support system combines the location based real time information about fire
and building technical systems like fiery spaces, ventilation system’s status, activated loops of
the fire-extinguishing system and smoke control system etc. with static information of FM
like real estate’s layout, floor plans, location and effect areas of systems/equipments, spaces
of dangerous substances, valuable spaces, fire sections etc. and reports it to different kind of
end users. The context aware system supports different end user groups like fireman, local
control room operator and the personnel occupying the building etc. Reporting for local users
is based on the broadband data communication. Later the system will include also support for
city flood. Fire related part of the system is presently in test use in several big buildings in
Finland.
Practical experience of the system is limited. According to firsthand experience of fire
fighters the system worked except the cases when the performance of data link has failed.
Information content is useful but all data must be absolutely correct. The basic features of
emergency management application are usable but in the case of big buildings (lot of data)
very fast data link or locally replicated data is required. The system is needed even more in
the control room of rescue station as background information than in the leading rescue car.
One of the biggest problems from point of view of fire authorities is the limited number of
buildings connected to the system. There is also need for more reliable solutions supporting
automatic switching between different data communication networks in moving rescue car
when virtual private network (VPN) is used.
The biggest problem from building owner’s point of view is the possibility for misuse of the
information for criminal purposes by people having access to the system. On the other hand
the widespread adoption of the system has big potentials. The most important is lifesaving
(both rescue team and people inside the building) due to faster operation and decisions based
on correct and up-to-date information. There are also big saving potentials related to decrease
of damages in buildings and related property.
From general system integration point of view the integration of building information systems
enables the development of new kind of applications which utilize any information existing in
information space. The emergency management support system developed is a good example
of the potential of the systems integration.
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Advanced Application of Real-time Integrated Building
Acknowledgements.
The results of this paper are based on “PARK” project. Following companies have been
participated and funded the project.
Project implementation: Ramboll Finland Oy and VTT.
Building Owners of Pilot- Buildings: Nordea Life Assurance Finland, Fortum Oyj, Jorvi
Hospital, YLE - Finnish Broadcasting Company, Helsinki University of technology, Sello
Shopping Centre, Tampere University Hospital, Turku University Hospital, Helsinki
Association of Parishes, Rautaruukki Oyj, Stockmann Oyj, Oulu University Hospital.
Fire Safety, Building and Construction, Telecom and Other Companies: Siemens Oy, Esmi
Oy, Fläkt Woods Oy, Falck Security Oy, Marioff Corporation Oy, HB Sisäilmatutkimus Oy,
TeliaSonera Finland Oyj, Buildercom Oy, NCC Building / Property Development, Invisian
Oy, Inpecta Oy, Axel Group Logistic Systems Oy, WM-Data, Securitas Systems Oy, State
Security Networks (Finland’s Public Authority Network VIRVE).
Insurance Companies: Federation of Finnish Insurance Companies, IF Insurance.
Public Authorities: Helsinki Rescue Department, West-Uusimaa Rescue Department,
Emergency Response Centre Administration.
Financing: Tekes.
References
1. Piira, K.: Pelastusautoon raportoiva kiinteistö – PARK (in Finnish). Pelastustieto
(Palontorjuntatekniikka - erikoisnumero), Vol 56. (2005) 6-8
2. Piira, K., and Lappalainen, V.: Supporting disaster management by means of ICT. Clima
2007 Wellbeing Indoors Conference, Helsinki (2007)
3. http://www.w3.org/2002/ws/
4. MacKenzie, C. M., Laskey, K., McCabe, F., Brown, P. F., and Metz, R. (eds.): Reference
Model for Service Oriented Architecture 1.0, Committee Specification 1, OASIS (2006),
http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=soa-rm
5. http://www.echelon.com/communities/developers/lonworks/
6. http://www.opcfoundation.org/
7. https://www4.sonera.fi/alerta/
8. http://www.sonera.fi/Yrityksille/Tietoliikenne/Informaatiologistiikka//H%E4lytyspalvelut
9. Koskinen, T Nettisovellusten tietoturva Automaatio talotekniikassa - nettiratkaisut ja
järjestelmien parempi hyödyntäminen, EVTEK, Espoo (2005),
http://www.automaatioseura.fi/index/tiedostot/BAFF_Timo_Koskinen.pdf
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Towards a Reference Model for Building Lifecycle Performance
Measurement
Iris Karvonen1, Kari Nissinen1, Timo Kauppinen1
Attila Dikbas2, Kerem Ercoskun2
Miguel Segarra3
1VTT P.O.Box 1000, 02044 VTT, Finland
[email protected], [email protected], [email protected]
2 ITU (Istanbul Technical University)
[email protected]
3 Dragados
[email protected]
Abstract
The paper discusses the development of a reference model for performance measurement in construction, especially focusing
on performance of the building (not building process). The objective is to improve the measured object (building and
related services) and its value to the customer and other stakeholders; taking into account the whole building lifecycle. The
evaluation metrics will be linked to value-based business models, thus making the earning of the developer, constructor or
service provider dependent on the building performance. The paper is based on the review of previous research in
performance measurement in construction and further development in I3CON-project.
Keywords
Performance measurement, Building life cycle
1
Introduction
EU FP7 project I3CON aims at developing models and methods for intelligent performance
measurement of buildings, taking into account the whole lifecycle. By measuring the
performance of the building the objective is to focus on customer value; what the customer
really gets. Finally the aim is to develop value- or performance-based business models. In
performance-based business models the end product to the customer is not the physical object
(building) but the value and performance given by the building and the linked services. The
payments from the customer are dependent on the delivered value which is measured by the
performance metrics. This affects also to the requirements for the metrics: the measurement
results should be indisputable. The objectives are further described in chapter 2.
The paper gives a short review to the previous developments in performance measurement in
construction in chapter 3. There is a large variety of different approaches, categories and
standards in this field. In many cases the focus is more on the construction processes than the
end product. Some of the approaches are focused on a specific item like decreasing energy
consumption or other objectives related to the environment.
The challenge of I3CON is not to invent new Building Performance measures as such but to
develop a reference model how building performance measures should be defined and used to
support Value-based Business Models in construction industry. As the first step towards the
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Advanced Application of Real-time Integrated Building
reference model, a performance measurement template has been defined in chapter 4. The
template aims to define the characteristics and relationships of a performance measure and a
framework to organize the previous approaches and metrics.
To support the development, a case study is presented in chapter 5, with an approach to use
the building automation system to support the measurement.
2. Objectives for building lifecycle Performance Measurement
Performance measurement has many application areas and thus also several definitions exist.
A general definition of wikipedia is the following:
"Performance measurement is the use of statistical evidence to determine progress toward
specific defined organizational objectives." [1]
Performance measurement can also be seen in the context of Performance management: “PM
is part of Performance Management. Performance Management comprises planning,
measurement, monitoring and assessment, improvement and rewarding of performance.” [7].
Both the definitions imply that the objective of performance measurement is to support the
achievement of objectives, by improving the processes, organization or the result of activities
(for example a product or customer value). Some approaches (for example Balanced
Scorecard [9]) presume the attention of the objectives of different stakeholders when
specifying a performance measurement system. When applying performance measurement in
the context of value-based business models the main stakeholder is the customer and the
measurement should be able to measure the value received by the customer.
Performance goals for a system, for example a building, can be set up. Performance
measurement requires gaining evidence (data or information) about the performance. The
evidence can be used to identify needs for improvement and to learn from previous
operations. Performance estimates can be followed already during the design and
implementation phase of a product, for example a building, and continued along its lifecycle.
The evidence can also be used to reward or punish from the realized performance. In some
cases performance measurement is used to optimize the system performance, for example in
relation with the required inputs.
Performance measurement generates performance measures (qualitative or quantitative
metrics). The metrics can be further used and consolidated to performance indicators.
Criteria can be linked both to the metrics or to the calculated indicators, and even to
qualitative measures. The criteria present values, to which the performance measures/
indicators can be compared, either minimum or maximum values or an interval. There are
different ways how the criteria can be used: as threshold values for alarming, as acceptance
criteria or as criteria to define the payment to the value provider.
In I3CON the main focus is on the performance of the building product, not the building
process, even if the efficiency and quality of the building process affects also the building
performance. As usual in performance measurement, the aim is to improve the measured
object, in this case building and related lifecycle services, and the value to the stakeholders.
However, the aim is not necessarily the optimization or maximisation of the building value or
efficiency. For I3CON reference model the objective is to support the implementation of
value-based business models, taking into account the whole building lifecycle.
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3 Existing approaches for performance measurement in buildings
Building performance can be defined as the group of valuable properties of the building to its
users. Shortly said a high-quality building ensures productive, healthy, safety and comfortable
environment to its users. When aiming to a high-class built environment clarifying the user
needs and requirements is perhaps the most fundamental issue. The better requirements are
set, the better the performance of the building and the building services can be defined.
Recently a certain methodology, building commissioning process, has been developed in an
international research project to ensure the building performance during its’ whole life cycle
[6].
Buildings are comprised out of numerous different and sometimes rather complicated
building elements and technical systems. Some of these systems are easier to control and
manage than the others. Similarly some of the building properties are less complicated to
verify than the others. On the other hand the national building codes often strongly control
some of the critical performance factors for instance stability and safety related performance
factors.
Different approaches and standards for building performance measures are presented more in
detail in [4]. Some of the most commonly used building performance indicators are listed in
the following:
Indoor conditions & indoor climate factors:
• Thermal comfort: indoor and globe temperatures (°C), air velocity and draft (m/s), air
supply and exhaust temperature (°C), stratification (layering) (Δ°C) and Predicted mean
vote (PMV), Predicted percentage dissatisfied (PPD) and actual mean votes (AMV) [10].
• Ventilation rate: air change rate (1/h) and air volume flows (l/s, l/s per m2, l/s per person).
• Air quality: relative humidity (%), CO2-content (ppm), TVOC (ppm), other gaseous
emissions (ppm) and microbes (units/m3).
• Acoustics: sound insulation (dB), sound impact (dB), background noise (dB (A)), HVACnoise (dB (A)), reverberation time (s), noise criterion (NC) and noise rating (NR).
• Illumination: daylight and artificial light (lx, cd, lm) and glare (lm-distribution).
• Vibration: (m/s2).
Building envelope structural factors:
• Thermal performance: U-value (W/m2,K) and sun radiation (power penetration %).
• Air tightness: air change ratio (1/h@50Pa)
• Thermal mass: heat capacity (kg, kWh/kg, °C).
Energy efficiency and sustainability items:
• Heating, cooling and ventilation: energy consumption (kWh/a, kWh/m2,a, kWh/m3,a).
• Electricity including lighting and machinery & equipment: energy consumption
kWh/m2,a, kWh/m3,a).
• Water and waste water: consumption (m3/a, m3/person,a, l/person day).
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• Gas: consumption (m3/a, m3/person,a, l/person day).
• Emissions: amount of CO2 during the whole life cycle.
Life cycle cost related items:
• Primary costs: pre-design, design and construction costs (€/m2, €/m2,a).
• Operation and maintenance costs: administration, maintenance &repair, energy, water,
cleaning, waste
disposal & environmental, insurances & taxes and services costs (€/m2,
€/m2,a).
• Manor repairs and modifications: costs (€/m2, €/m2,a).
Space management related issues:
• Space programming and space use: efficiency (m2 per person).
• Services: service quality, service delivery, user friendliness, usability (by scale).
• Modifiability: applicability of a building for different uses.
Some of the performance factors listed above can be used in the design or construction phase,
some are used in the operating period of a building. There are several additional performance
factors that can be utilized depending on the stakeholder or the viewpoint. Performance
information of a building can be reached by many different kinds of design quality indicators,
key performance indicators (KPIs) or even post occupancy evaluations. Furthermore, there
exist several different types of classification systems and principles that can produce valuable
performance information in the area of construction and building industries; for instance
energy efficiency classifications, indoor air classifications or BREEAM [8] that is one of the
most widely used environmental assessment methods for buildings.
Systematic building performance control requires continuous monitoring as well as detailed
surveys or audits at certain intervals. Today it is possible to connect monitoring with the
building automation and maintenance record systems. The most sophisticated systems can
produce relevant data in real time and the data can be utilized via internet or even mobile ICTapplications. Latest developments have created a lot of new business opportunities in the area
of building performance measurement. These opportunities are concerned with two types of
actions; specific checks at certain moments of the building life cycle as well as constant
monitoring of the vital building performance factors.
4. Developing a Reference model for lifecycle PM in construction
4.1 Objectives of a Reference model
Wikipedia [1] defines a reference model (in computing) as follows:
“Reference model: It is an abstract representation of the entities and relationships involved in
a problem space and forms the conceptual basis for the development of more concrete models
of the space, and ultimately implementations, in a computing context. It thereby serves as an
abstract template for the development of more specific models in a given domain, and allows
for comparison between complying models.”
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Even if this definition has been given in the computing context, it can be considered suitable
also in more general terms. The objective of a reference model is to make the development of
a system more efficient, by representing base models or patterns which can be used to design
a system or a solution. Reference models may be presented at different levels of abstraction
and at various levels of generalization [2]. Also different types of reference models can be
identified [3]:
- Generic reference models can be used to create particular models by parameterization. To
enable the deployment by parameterization the reference model may need to be defined to a
fairly fine granularity.
- Paradigmatic solution: the reference model is presented as an individual typical solution or a
set of previous cases. Particular models are created by changing details. Paradigmatic
solutions have a relatively small design space.
- A reference model may be composed of a set of modular components and rules of how to
combine them. The modules should be generic, simple, discrete units with well defined
interfaces. They can also be recursive entities, allowing the decomposition to sub modules.
Through configuration the modular reference models also allow larger design space.
In principle it is also possible that a reference model is a composite of parts representing the
different types, at most a set of parameterized modules, complemented with case examples.
As well as modelling in general is dependent on the purpose of the modelling, also the form
of a reference model is dependent on the context and use of the model. The objective of a
Reference model for Performance metrics & criteria to be developed in I3CON-project is to
assist in the design of a measurement system for building lifecycle performance, supporting
value-based business models. In this context the Performance Measurement (PM) reference
model could give a presentation and guidance in three aspects:
• The presentation of the objective and use of the PM metrics: WHY Performance
Measurement is applied? In I3CON-project the aim of performance measures is to
support Building Lifecycle Value-based Business Models. How is the link to the Business
Model presented and how should it be taken into account in the design of a PM system?
• The presentation of the performance measure entity: WHAT is it composed of, what kind of
defining features does a Performance Measurement entity have? This presentation should
answer to the question: WHAT does the Performance measure or indicator & criteria
specification include? In I3CON this specification is implemented by developing a PM
template which can be used to describe existing and advanced PM metrics. The template
may also be used to define a PM classification or to select between different classifications.
• The presentation of the PM specification & implementation process: HOW to select or
configure the metrics for a specific business case. This could be presented as a simple
process model defining the main phases and decision criteria.
With this specification the reference model is mainly directed to partners interested in offering
Value-based products and services to the customers (building end-users, owners or tenants).
They could be investors, contractors or service providers; covering the whole building and
environment or only selected parts or attributes of the building. On the other hand, potentially
also customers interested in acquiring value-based services could utilize the reference model.
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4.2 I3CON PM template as an early development for a reference model
As the first step towards a PM reference model a draft PM template has been developed to
describe the essence of performance measures [4]. The purpose of the current template has
been to:
• collect together the most relevant existing PM systems from different sources,
• to present a categorisation in which these measures can be compared and similarities can
be identified,
• to describe a pattern for the main characteristics of performance measures & metrics,
• to use the pattern to describe selected PM & metrics.
The development of the template started from organizing information from existing PM
systems in construction. The current template fulfils the first task above and makes a first
proposal for the categorisation. It also makes a first selection of the relevancy of the metrics
for I3CON-project. The template is implemented as an excel tool which allows to filter the
large set of metrics according to the categories. Figure 1 illustrates the main elements of the
matrix.
Metrics
Metric
Categories
I3CON
Metric
Categories
Referenc
e to the
Metric
Standard
Selected
I3CON
Metrics
Type 1 Metrics
Type 2 & Type 3 Metrics
Figure 1. The I3CON Metrics template elements.
Even if started from the organization of existing approaches, it was identified that a metrics
template could serve as a part of the I3CON PM reference model. To comply with this, the
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template still requires some development. To act as a presentation of a PM entity additional
descriptive fields are needed. The current pattern for performance measure description
involves the following columns: belonging to category, relevancy to I3CON, origin, sub-topic
and metrics name. The pattern could be complemented with fields detailing the
characteristics for selected metrics, for example: indicator description, link to (business)
objective and business model, relation to other indicators and formula; how to evaluate the
indicator from data (which data), measurement timeframe, definition of criteria and link to
life cycle phase and potential services.
5 Case example
As an example of performance measurement of buildings a case study of a school in Southern
Finland is described here. The School of Westendinpuisto was opened for the autumn season
2005. The school is owned by City of Espoo, but facility management and tenant service is
operated by a private company, which has also other contracts in different parts of the
country. The contract between the city and the company covers the technical services and
maintenance, guarding and cleaning. The new operations model was created by the city of
Espoo. The contractor and the producer of facility and tenant services tend toward a persistent
co-operation and also to have the most efficient life-cycle costs. Traditionally the city
organization has taken care of maintenance and other services, but the trend nowadays seems
to be toward purchased services.
In the testing, adjusting and balancing (TAB) phase the Building Commissioning procedure
was tested. The procedure was created in a research project [6], partially adapted existing
concept in USA and also the results of IEA Annex-46 project [11]. The aim of Building
Commissioning-project was to develop a procedure for the whole service chain from the predesign phase to the use stage. More detailed measures also in the TAB-stage will confirm that
the conditions and the performance of the building fit to the requirements and also the
customer needs.
The design intent included general goals and specified targets for heating, cold rooms, town
mains and sewers, for ventilation, building automation, operation and maintenance manual
and for drawings and other documents.
As an example some details of the specified goals and indicators:
• Heating: the building is connected district heating; defined space reservation for
operating room; heating energy measurements must be connected to control system; the
consumption target for heating energy was 25 kWh/m3 (cubic content)
• Town mains and sewers: the annual consumption target for water 0,07 m3/m3 (cubic
content)
• Ventilation: target value: microclimate of room class S3 (according to Finnish indoor air
classification); an option to increase the rate of air exchange and air flows by 20 % in
classrooms, according to the needs, based on the control of demand; Cleanliness
classification: cleanliness on construction works must be equal to P2 (according to Finnish
design instructions “Clean ventilation system”); aim to reasonable small pressure losses in
sizing of ventilation system; the rated value of fans must be fitted for SFP-characteristic 1,9
kW/m3/s.
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The selected building automation system has on-line and graphic user interface. It has
different features, such as graph pages, time programs, and trend monitoring and alert
displays. Beyond the building automation system there are two management tools: Internetbased operation and management manual (FimX) which is in connection to Building
Automation System and also internet-based facility management software (RauInfo). The
performance and consumption reports are generated by RauInfo.
The instrumentation level and facility management tools in that particular school represent a
modern practice in the present. For instance, the values and factors which are continuously
monitored and saved include e.g.
• degree day number, the consumption of the facility electricity (daily and hourly), the
electricity consumption of air supply units (daily and hourly), electricity consumption of
kitchen (daily and hourly), electricity consumption of outdoor lighting,
• the consumption of district heating energy and district heating water(instantaneous, daily,
hourly)
• the consumption of service and warm water of the facility and the kitchen (instantaneous,
hourly, daily)
• various room temperatures etc
The most important question is how to generate a suitable model for a report which will show
the most important key figures and factors with no efforts, at a glance. The displays especially
in schools and in other public buildings would be very effective in increasing the common
awareness.
6. Conclusions
The objective behind this work is to define a reference model for building lifecycle
performance measurement, with the aim to support value-based business models. These
measures should be able to define and measure the customer value and to validate the
achieved building value. The focus is not the construction process but the building itself.
However, having the lifecycle scope means that the building lifecycle must be taken into
account and thus the processes cannot be totally omitted.
There are several different approaches, standards and metrics for Performance Measurement
in construction. Some of them are built on user requirements, including directives. There are
several developments focused on specific targets like sustainability or minimizing energy
consumption. The measurements are typically directed both to the construction or
maintenance processes and the building. Some of them have links to specific business models
but they are mostly designed for the improvement of building quality.
The challenge of I3CON is not to invent new Building Performance measures as such but to
identify a framework how building performance measures should be defined and used to
support Value-based Business Models in construction, taking into account the extensive
previous work. There are several classifications, standards or approaches for performance
measurement in construction. Some of them are more focused on production and processes
while the focus here is the performance of a building.
To organize the existing, partly overlapping measurement classifications, a first version of a
performance measurement template has been defined for the starting point of the reference
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model. The template will be further developed to indicate the applicability of the existing
measures for Performance-based Business Models, and potentially to identify insufficiencies
and additional measures.
References
1. http://www.wikipedia.org December 2007.
2. Bernus, P., Mertins, K.. Reference Models in Bernus, P., Mertins, K Schmidt, G. (edit.),
Handbook on architectures of information systems. ISBN 3-540-64453-9 Springer 1998,
page 615-617.
3. Bernus, P., Baltrusch, R., Tolle, M., Vesterager, J. Better Models for Agile Virtual
Enterprises – The Enterprise and its Constituents as Hybrid Agents. In Karvonen et al.
Global Engineering and Manufacturing in Enterprise Networks (GLOBEMEN), VTT
Symposium 224, 2003,
p. 91-109.
4. I3CON D2.2.-1 Lifecycle Performance Model, Reference Model for Metrics and Criteria,
www.I3CON.org. September 2007
5. VTT ProP®. 2004. EcoProP software and VTT ProP® classification. Web site, verified on
31thMay 2004. (http://cic.vtt.fi/eco/e_index.htm )
6. Pietiläinen, J., Kauppinen, T., Kovanen, K., Nykänen, V., Nyman, M., Paiho, S., Peltonen,
J., Pihala, H., Kalema, T., & Keränen, H. Guidebook for life-cycle commissioning of
buildings energy efficiency and indoor climate. VTT research Notes 2413: 173 pp+56 pp.
ISBN
978-951-38-6969-4,
ISSN
1235-0605
Espoo
2007.
"http://www.vtt.fi/publications/index.jsp"
7. Westphal, I., Mulder, W., Seifert, M. Supervision of Collaborative Processes in VOs. In:
Camarinha-Matos L.M., Afsarmanesh H., Ollus M. (eds.) Methods and Tools for
Collaborative Networked Organizations, Springer (to appear in 2008).
8. BREEAM. Fact file. Version 5. October 2007. http://www.breeam.org/
9. Kaplan, R.S., Norton, D.P. The Balanced Scorecard - Measures that drive performance.
Harvard Business Report, January-February 1992.
10. ISO 7730. Moderate thermal environments; Determination of the PMV and PPD indices
and specification of the conditions for thermal comfort . Geneva, Switzerland, ISO, 1984.
11. http://www.annex46.org/ December 2007.
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Advanced Application of Real-time Integrated Building
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Business Innovation in Construction through Value Oriented
Product/Service Offerings for Living Buildings
Wim Gielingh1, Hennes de Ridder1, Lout Jonkers2, Harry Vedder3,
Reza Beheshti1,
1
Marco Dreschler1, Sander van Nederveen1, Saban Ozsariyildiz1, Jules Verlaan1, Ruben
Vrijhoef1
Faculty of Civil Engineering and Geosciences, Technical University of Delft, The Netherlands
2
3
BSS, Arnhem, The Netherlands
M3V, Arnhem, The Netherlands
Abstract
Current business offerings in construction assume that client needs remain fixed over the lifetime of a building. Business
process innovations focus up to now also mainly at initial construction and on cost reductions, less on subsequent lifecycle
phases and on the creation of user value. Construction is therefore not fully capable to meet changing user, social and
environmental needs, and is not rewarded for value adding concepts. The current cradle-to-grave thinking causes substantial
waste, environmental damage and destruction of capital. Buildings under-perform from an economical and ecological
perspective. This paper presents a new business concept in the form of value oriented Product Service Offerings for Living
Buildings. A provider of Living Buildings adds value to the business of its clients and is rewarded for that. A provider is
proactive and manages a portfolio of industrially produced, customizable solutions. During operation, user processes as well
as social and environmental processes are closely monitored, and the building is kept fit-for-use during its entire functional
life. Modules, components and materials that are released from a building after they have become dysfunctional, are
remanufactured for reuse in the same or other buildings. This reduces waste, reduces the energy-intensive production of base
materials for new buildings and saves construction costs. Living Buildings are expected to be less vulnerable for depreciation
than traditional buildings and offer therefore an attractive alternative for investors.
Keywords
Living Buildings, Business Innovation, value creation, cradle-to-cradle, remanufacturing, product-service system.
1 Introduction
1.1 The Need for Dynamic Solutions
Current business models in construction, as well as current forms of contracting, assume that
client-, market- and social needs remain fixed over the lifetime of a building. Requirements
are pinned down in specifications and contracts. Any deviation from an agreed specification,
regardless whether it stems from the client or from the contractor, is not appreciated.
Deviations lead often to time- and budget-overruns or, even worse, to legal disputes.
But in reality, user needs and social or environmental boundary conditions are continuously
changing. Static infrastructures, buildings and related processes may therefore soon result in
under-performance. Given the huge capital investments needed for the creation of new
buildings and infrastructures, and given the often irreversible impact of building permissions
on landscapes and townscapes, this causes high risks for investors, users and governments.
The current static approach results often in an over-specification of requirements, and in an
over-dimensioning of built artefacts. After all, if a building is assumed to exist 30 years or
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Advanced Application of Real-time Integrated Building
more, the client cannot just define only present requirements, but has to predict also long term
future requirements. Such requirements depend often on external factors that clients cannot
control, such as social and environmental factors. And reversely, if a building supplier has to
guarantee performance and quality for a long period of time, he will choose durable but costly
materials, will over-dimension the building, and plan strict maintenance procedures in order
to meet the requirements.
It is of course possible to produce buildings with a shorter lifetime. But the capital
investments in buildings are usually so high that they cannot be written off in a short period of
time. Moreover, the need to demolish a building after a short period worsens the already
existing problem of excessive waste.
Dynamic thinking in construction is not new. Several initiatives have been taken in the past to
realize buildings, often using industrial production techniques, that can be changed if user
requirements change. Probably the most well known concept in this respect is Open Building
[1, 2]. An Open Building has a fixed, durable, main structure, and a flexible infill. The Open
building concept is primarily an architectural - and partially technical - answer to the problem.
More and more construction companies offer today mass-customized solutions, based on
industrially manufactured building systems and production automation. Clearly, these are
steps in the right direction to improve the efficiency and quality of construction. Most
industrial solutions are however positioned as alternatives for traditional contracting and aim
therefore primarily on the reduction of initial (capital) costs, not on reduced Total Lifecycle
Costs, reduced risks or increased client value. Furthermore, a building that is customized and
made fit-for-use at the beginning of its lifecycle, may not remain fit-for-use at a later stage.
Buildings that deviate from average market requirements are perceived as risky investments
but will never be optimal solutions for users.
1.2 Structure of this Paper
Chapter 2 presents a model of four levels of business efficiency. It clarifies the difference
between PSS (Product Service systems) and current business offerings in construction.
Chapter 3 discusses the Living Building concept as a special PSS for construction. It was
developed by de Ridder for the PSI Bouw programme in the Netherlands [5].
Chapter 4 discusses general aspects of the Living Building Concept. Chapter 5 addresses the processes of
vitalization, remanufacturing and value creation. Chapter 6 discusses an action research programme that is
currently initiated and draws some final conclusions.
2.
An Introduction to Product Service Systems
2.1 Four Levels of Business Efficiency
The construction sector is today under pressure to change. This process started around 1987,
when global energy-prices dropped and oil- and gas-companies postponed investments in new
facilities. The business in that part of construction that serves the oil and gas sector collapsed.
In order to survive, some of these companies developed new business concepts, which
eventually led to integrated solutions, up to operation, financing and ownership of a facility
(DBMFOT). Through these offerings, in particular through the application of Concurrent
Engineering and Electronic Document and Workflow Management, it appeared to be possible
to reduce Total Lifecycle Costs considerably [3, 4]. Client organisations in other sectors are
since then also experimenting with integrated project forms, which are occasionally client led,
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but more often outsourced. A performance oriented rewarding scheme intends to avoid
conflicts of interest between client and provider, and should guarantee that the projects deliver
the desired output.
The efficiency of a modern enterprise with respect to the delivery of a particular end result
can be expressed on a scale that has four distinctive levels; see also figure 1, left.
1. An enterprise that offers capacity, such as human capacity, is paid based on time spent on a
job. It does not sell the results nor the way in which these results are obtained.
2. On the second level enterprises offer processes, such as in the form of projects. They
commit themselves to execute a project within time and budget. Results are variable and
differ from project to project.
3. On the third level enterprises offer products or services to their clients. They commit
themselves to time, budget and results, but not to (end) user value.
4. On the fourth level, integrated packages of products and services are offered. Providers
commit themselves to the maximization of user value.
value oriented
PSS
efficiency
products and services
optimized for client value
product
Living Building
(customized)
products &
turnkey solutions
processes optimized for products
process
project
integrated
DBMFO
capacity optimized for processes
capacity
traditional
client value
Figure 1. Four levels of business efficiency (left) versus client value.
The most widely applied business model in construction today is the offering of capacity. In
order to bring competences together and to spread risk, enterprises form consortia. Processes
depend on client order. ICT is mainly restricted to ERP (Enterprise Resource Planning).
Process orientation is characterised by competences with respect to project- and process
management, and the project-wide utilization of workflow and document management
systems. Well known applications in construction are the seamless team approach and
integrated DB(MFO) projects.
Product orientation is characterised by the fact that enterprises have a portfolio of
predetermined solutions that exist independent of client orders. These solutions can be
configured and customized to comply with specific client needs. Processes do not depend on
client order but are optimized for the product being delivered. Enterprises that offer products
usually apply advanced 3D or nD (parametric) CAD systems that are integrated with
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Advanced Application of Real-time Integrated Building
Computer Numerically Controlled (CNC) production automation technology. They have fixed
(order independent) supply chains that can be optimized for collaborative engineering and for
logistics. Examples in construction are turn-key solution providers.
Value oriented product/service systems form the fourth level. A combination of products and
services aims at the delivery of the highest client value for the lowest costs. In terms of ICT,
enterprises use most - if not all - of the abovementioned applications as well as Costumer
Relationship Management systems. Value oriented PSS offerings are still rare in most
industries as well as in construction. The concept will be described in more depth in section
2.2.
The four levels form essentially a stack: each level makes use of the efficiency gains at a
lower level. Hence, the offering of value oriented product/service combinations is not possible
without having products and services.
2.2 Product Service Systems
Goedkoop et.al. [6] define a Product Service system as "a marketable set of products and
services capable of jointly fulfilling a user’s need". Key-factors of success are:
-
to create value for clients, in economic sense or by adding quality and comfort,
-
to customize solutions to meet specific client needs,
-
to create new functions or to make unique combinations of functions,
-
to decrease the threshold and risk of capital investment by sharing, leasing or renting,
-
to decrease environmental load and to deliver eco-benefits,
-
to respond better to changing client needs.
Product Service Systems introduce a different way of doing business and require new kinds of
contractual arrangements. They have the potential to unlink environmental pressure from
economic growth [7].
An example of a product service system is the one offered by producers of printing and
copying machines, such as Xerox and Océ [6, 10, 11]. In their PSS business models the
companies do not sell printing or copying machines but a printing or copying function.
Clients pay for the output of a machine and for quality and reliability. The combination of
product and service is designed to deliver performance. If a machine runs out of toner, it
automatically orders a new cartridge which may be delivered and installed by the provider.
The condition of operational machines is monitored through sensors that record the number of
copies made, paper-jams, heat and/or other critical performance criteria. Before a machine
breaks it can thus be repaired or replaced by a 'new', more reliable one. If the requirements of
a client changes, the provider replaces a machine by a new one. 'Old' machines are taken back
and disassembled. The parts are remanufactured and used again for the production of new
machines. This reduces waste and the costs of making completely new machines from fresh
natural resources [11].
3.
The Living Building Concept
The Living Building concept [5, 8] is a Product Service offering for construction. An LB
provider takes full Extended Lifecycle responsibility for buildings and their parts. The
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provider is thus not hindered by the current fragmentation in the construction sector. Very
much like what is common practice in other industries, LB providers have a supply chain
which is strategic and thus independent of client orders.
Providers develop a portfolio of solutions for specific product/service - market combinations,
such as for housing, education (schools), health care (hospitals), retail (shops, retail centres,
airports), business (offices) or infrastructures (bridges, roads). A solution consists of a
building concept and a suite of services that both can be customized to specific client needs.
An LB contract aims at the delivery of maximal value for minimal money; it does not freeze
user requirements or building performance. If user requirements or external conditions change
such that the building does not any longer offers the best solution, it will be changed. Goal of
the LB concept is therefore to keep a building fit-for-use, not just for once, but always!
A provider does not wait until clients or users start to complain. The provider understands the
type of processes that are facilitated by the building, and is proactive. User processes, social
and environmental boundary conditions, as well as building performance, are continuously
monitored. If any of these conditions change such that the building becomes sub-optimal, the
provider may adapt the building and/or service. Depending on details in the service level
agreement and impact on the agreed price, the provider can do this autonomously or by
mutual agreement with client and/or user.
For each modification requirement, there may be zero, one or more solutions. Each solution
will have its benefits and implications. These benefits and implications are considered in a
broader context: change requirements can be addressed more economically by combining
them into a single solution. Decisions about modifications are thus based on a rationale, in
which integral benefits are weighed against integral implications.
The whole of benefits will be called 'value', while the whole of implications will be called
'cost'. Values and costs may however not be limited to financial values and costs. Amongst
the factors that can be incorporated in a value/cost model are social, cultural, environmental,
ethical and esthetical values, as well risks, wellbeing and health.
client benefit
yield
price
value
cost
provider profit
dynamic space
(control space)
Figure 2. A price is agreed between client and provider between value and cost. The provider has an incentive to
increase yield by cutting costs or by increasing client value.
There are apparently many different, practically incomparable values and costs.
Environmental values may have to be weighed against economical costs. Reversely,
economical values may also have to be weighed against environmental costs.
It is currently common practice to express all values and costs in terms of money. Money has
however specific characteristics, such as interest, inflation, artificial scarcity and relationship
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Advanced Application of Real-time Integrated Building
with debt, that make it less suited for the expression of non-commercial values. An
investment in an installation for solar energy that gives an annual return of 2,5 % may be
perceived as non-economical if the same investment may raise 3,5% annual interest if it is put
on a bank. It is however questionable whether money provides us with a proper yardstick to
measure the long term value of investments. Money is subject to inflation (i.e. it looses value
over time), while the price of energy will increase over time. The former banker Lietaer
develops new kinds of money that are better suited for the expression and exchange of social
and environmental values than current money [9].
An LB contract does not specify a fixed performance for a fixed price, but defines an agreed
value-cost balance. Within such an arrangement, the process is dynamically controlled: clients
can alter their initial demand and calculate the impact on the initial price, and vice versa.
Providers are encouraged to propose new solutions that reduce costs or deliver additional
value. An initial price will grow within this dynamic process in a controlled way to a final
price. Instead of enforcing the initial planned value against a fixed price calculated in the first
phase of the process, the price is based on actual delivered value during the process. The
range between basic price and the clients financial budget can be considered as the client’s
“control budget”. On the supply side, providers are enabled to reduce costs or increase value
(figure 2).
Given the possibility that buildings may change quite drastically during their life, it makes
sense that not the clients but the providers legally own the buildings. However, providers do
not rent or lease out buildings, but facilitate user processes. Hence, buildings may be multifunctional to facilitate the processes of multiple clients. This creates new business
opportunities for clients and results in substantial cost efficiencies.
4.
The Process that Supports Living Buildings
4.1 Vitalization.
The term 'maintenance' is used today for the servicing activity that maintains a facility in its
original state. This term reflects the current static view on the functional needs for a facility. It
assumes that these needs do not change.
The servicing activity that aims at the maximization of yield is described by the term
'vitalization'. It incorporates not only traditional maintenance, but also modification of the
facility to serve changing functional needs.
Vitalization of a building may mean that the building has to be extended or to be scaled down.
In the latter case, building components will be released. If the Living Building concept would
be applied according to traditional cradle-to-grave thinking, downscaling would be identical
to (partial) demolition, which creates substantial waste. The Living Building concept adopts
therefore the cradle-to-cradle principle [17]: modules or components that are released from a
building because their functional need has disappeared will, as far as possible, be reused in
another building. As these modules and components will not be as good as new, they may
have to undergo a process of remanufacturing, such as cleaning, repainting, surface treatment
or repair.
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4.2 Remanufacturing
The idea of remanufacturing originated in the automotive sector, where demolition firms
started to disassemble cars, refurbished components, and sold these as spare parts for similar
types of cars. Remanufactured parts can be produced at around 50% of the costs and saving
up to 80% of the energy and CO2 emissions as compared with the production of new parts
[11]. Remanufacturing saves the use of the Earth's limited resources and reduces the
production of waste.
It is expected that car manufacturers will very soon be enforced by legislation to take back
used cars, so that the components and materials from which they are made will be used as a
resource for the production of new cars. Consequently, car manufacturers design new car
models such that they are not just easy to assemble, but also easy to disassemble and
remanufacture. Advanced manufacturing technologies used today for production will also be
applied for disassembly and reuse. Given the increasing costs of raw materials and energy,
companies that master this process well will have a leading edge over companies that apply
cradle-to-grave thinking [10, 17].
Remanufacturing is not any longer restricted to the automotive sector. It is increasingly
applied in many other sectors, often in combination with Product Service systems that aim at
the creation of client value [16].
The business case for remanufacturing may even be larger for construction than for other
sectors. This is because:
a) buildings and other constructed artefacts are massive relative to other products so that
there is a higher incentive for reusing materials,
b) the technical and physical lifetime of components and materials used for construction is
generally longer than their functional lifetime, and
c) remanufacturing, in combination with vitalization, extends the value lifetime of buildings
and thus reduces the risks of capital investments.
4.3 The Living Building Process
The envisioned process of a Living Building product/service provider is sketched in figure 3.
The left side of this diagram shows, from bottom to top, indicated with red arrows, the full
construction process that starts traditionally with the extraction of raw materials from natural
resources. Raw materials are chemically and often thermally processed for the production of
base materials. Base materials are subsequently manufactured to become components for
assembly.
In case changes of the building are needed during its operational life, the building will be
partially disassembled and re-assembled. Removed modules may be re-used for assembly in
the same or another building. If modules cannot be re-used as a whole, they will disassembled
into components. Disassembly can be drastically simplified if fixtures of components and
modules are designed for that purpose. Further, given the fact that vitalization may take place
in a fully operational building, main disassembly and re-assembly should be designed such
that ongoing activities in the building can continue with little or no disturbance.
Apart from cleaning, remanufacturing implies often surface treatment, such as the removal of
corrosion and paint, repair of scratches and dents, and the addition of new coating layers. In
some cases, remanufacturing may require also shape modifications. In a few cases it implies
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Advanced Application of Real-time Integrated Building
melting or chemical processing, so that the base materials can still be reused. Reuse of
components or modules without melting or chemical processing has the least environmental
impact and is therefore preferred [14, 15].
A detailed study of the lifecycle energy of twenty Australian schools indicates that the total
embodied energy in a building can be as much as 37 years of operational energy [18]. In
addition, it should be realised that the production of materials such as cement, brick, steel and
glass require very high temperatures that currently can only be realised through the burning of
carbon hydrogen's. For the heating and electricity consumption of buildings there are other more environment friendly - energy sources available. Although building styles and local
climate conditions may affect comparisons between embodied and operational energy, it is
clear that the reuse of building materials can significantly reduce building related CO2
emissions.
Remanufactured components or modules are 'as good as new'. Before installation they are
stored in a warehouse. As these components or modules are then readily available, the
construction process can be very fast compared with traditional processes.
Ultimately, all buildings produced by the provider will be a mixture of remanufactured and
newly manufactured components and systems. Remanufacturing extends the technical
lifetime of components so that overall construction costs and building lifecycle costs will
reduce.
This concept even enables differentiated service offerings, such as luxury buildings made
predominantly from new components, and 'economy class' buildings made from
remanufactured components.
The top of figure 3 shows, with blue arrows, the value creation process. Goal of this process is
to anticipate on changing client and user needs, so that adequate solutions can be developed as
part of the product, the service, or both. This process is supported by three monitoring
functions: (a) the monitoring of social and environmental conditions that may affect user
processes and perceived building performance, (b) the monitoring of actual user processes,
and (c) the monitoring of actual building characteristics and performance. A building can only
be kept fit-for-use if its perceived performance remains high. Factors that affect perceived
performance are fashion and market trends, new social insights and new technologies.
Further, buildings such as schools, retail centres, airports, hospitals, hotels, offices and also
houses support processes that may frequently change, perhaps even every 5 to 10 years.
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Social & environmental processes
Social & environmental condition monitoring
Impact on user processes & clients business
User processes
User process & requirements monitoring
Value
Creation
Process
Building performance monitoring
Operational Services
& Dynamic Control
‘the output’
Buildings in operation
‘the hardware’
main
assembly
module
assembly
component
manufacturing
light
maintenance
module reuse
module
remanufact.
component reuse
component
remanufact.
material reuse
material
remanufact.
main
disassembly
module
disassembly
Production &
Construction
Process
component
destruction
minimal use of
new base materials and energy
thermal
processing
chemical
processing
material reuse
Production
of Base
Materials
material reuse
minimal use of natural resources
minimal waste
Figure 3. The process of a Living Building provider aims at reducing costs in the construction process (red) and
the increase of client value (blue).
5.
Business Benefits
The long term capital value of Living Buildings will be substantially higher than that of
traditionally built buildings. Figure 4 shows the capital value of a building with an estimated
lifetime of 50 years. Traditional buildings have to be demolished, so that they end up having
negative value near the end of their life (figure 4 top). Remanufacturing turns 'waste' into a
capital resource for the production of new buildings (figure 4 middle). If combined with
regular vitalization, a Living Building will remain always fit-for-use, and thus retain a high
capital value during its entire (indefinite) functional life.
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Advanced Application of Real-time Integrated Building
The rewarding of Living Building product/service providers is related to performance, i.e.
maximal yield (value minus costs). Both client and provider have an interest in optimizing
yield, so that their relationship is non-adversarial.
demolition
Initial
construction
capital value of traditional building
+
-
T=0 jr
T=50 jr
Initial
construction
disassembly &
remanufacturing
capital value of remanufacturable building
T=0 jr
T=50 jr
T=0 jr
vitalization
vitalization
vitalization
Initial
construction
capital value of living & remanufacturable building
T=50 jr
Figure 4. The capital value of a building as a function of time, (a) for a traditional building, (b) based on
remanufacturing at the end of functional life, and (c) for a Living Building.
6.
Case studies and conclusions
One construction project of a Living Building has started in 2007. It concerns a secondary
school in Veenendaal, The Netherlands. Two more projects are currently in a briefing stage: a
hospital in Den Helder, and a city centre in Almere Haven, which includes a school, a
shopping centre and a residential area. As providers are currently not yet able to offer Living
Building Product/Service offerings as envisioned, these projects must be seen as pilots that
are part of a larger action-research programme.
In all three cases the offering of multi-functional solutions to clients appeared to create
interesting new opportunities. The hospital in Den Helder, for example, is currently housed in
an old building that doesn't meet modern functional needs. However, the future of this
hospital is uncertain. It may be that within ten years time the hospital has to move for
efficiency reasons to another town, about 30 kilometres away. In order to reduce the business
risks, it is investigated how the various sub-functions of the hospital can be shared with other
public or commercial functions. The restaurant and hotel function of the hospital, for
example, can be outsourced to a commercial hotel operator, which uses a part of the building
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for regular hotel operations. Such a model reduces the risks for both the hospital and the hotel
operator.
It is too early to draw conclusions from these case studies with respect to the practical
feasibility of the Living Building concept. But clients, investors and construction companies
have already expressed clear interests in this new kind of business offering. It is expected that
more pilot projects will be initiated in the near future, and it is hoped that through such pilots
providers will gradually improve their overall performance.
References
1. Kendall, S.: Open Building: An Approach to Sustainable Architecture; Journal of Urban
Technology, December 1999.
2. Habraken, N.; The Structure of the Ordinary, Form and Control in the Built Environment;
MIT Press, Cambridge London, ISBN 0-262-58195-7, 1998.
3. Baker, C.; The use of EDM systems for cost reduction in major projects (case study Agip
UK); CRINE conference jan/feb 1996.
4. Farrow, C.R., and W.Sutton; Harding Field – a North Sea Success Story; World Oil,
november 1998.
5. de Ridder, H.; Het Living Building Concept, een wenkend perspectief voor de Bouw;
ISBN 90-78572-01-9
6. Goedkoop, M., et al; Product Service systems, Ecological and Economic Basics. Report
for the Dutch ministries of Environment (VROM) and Economic Affairs (EZ), 1999.
7. Mont, O.K.; Clarifying the concept of product-service system; Journal of Cleaner
Production, 10 (2002) 237-245.
8. de Ridder, H. A. J., and Vrijhoef R.; Living Building Concept applied to Health Care
Facilities; Proceedings International Research Week, Manchester, 2007.
9. Lietaer, B.A.; The Future of Money; London, Random House, ISBN 1843451506.
10. Maxwell, D., van der Vorst, R.; Developing sustainable products and services; Journal of
Cleaner Production 11 (2003) 883–895.
11. Steinhilper, R.; Remanufacturing, The Ultimate Form of Recycling; Stuttgart (1998).
ISBN 3-8167-5216-0.
12. Manzini, E., and Vezzoli, C.; Product-Service Systems and Sustainability; UNEP, Paris,
ISBN:92-807-2206-9.
13. Gielingh, W., van Nederveen, S., de Ridder, H.; Organizational Implications of Product
Service Systems for Living Buildings based on a Minimal-Waste Business Scenario;
Proceedings WCPM conference 2007, Delft, ISBN 978-90-9022422-0.
14. Tomiyama, T.; A manufacturing paradigm towards the 21st century; Integrated Computer
Aided Engineering 4 (1997) 159–178.
15. Umeda, Y.; Nonomura, A.; Tomiyama, T.; Study on lifecycle design for the post mass
production paradigm; in: Artificial Intelligence for Engineering Design, Analysis and
Manufacturing (2000), 14, 149–161.
16. Greyson, J.; An economic instrument for zero waste, economic growth and sustainability;
Journal of Cleaner Production 15 (2007) 1382-1390.
17. Braungart, M., McDonough, W., Bollinger, A.; Cradle-to-cradle design: creating healthy
emissions - a strategy for eco-effective product and system design; Journal of Cleaner
Production 15 (2007) 1337-1348.
18. Ding, G.K.C. (2007) Lifecycle energy assessment of Australian secondary schools;
Building Research and Information, 35(5) 487-500.
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Advanced Application of Real-time Integrated Building
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Application of Modelling Techniques in Buildings and
Exploitation of BEMS
Piotr Jadwiszczak, Jan Syposz, Marta Laska
Faculty of Environmental Engineering,
Wroclaw University of Technology
Ul. Wybrzeze Wyspiańskiego 27, 50 – 370 Wroclaw, Poland
{piotr.jadwiszczak, jan.syposz, marta.laska}@pwr.wroc.pl
Abstract
Over the past two decades there was a rapid trend to design friendly buildings to occupants and natural
environment. To cope with high requirements regarding buildings, implemented installations, users and
environmental impact it is necessary to apply Building Energy Management System (BEMS) not only as
tool for a current system supervision, but also to fulfil the complex functions of reducing the energy
consumption in a building with respect to thermal comfort conditions. To achieve these aims it is
necessary to use modelling tools based on building numeric energy models and computational fluid
dynamics as powerful techniques in the advanced regulation processes and energy management. This
paper focuses on the research on computer BEMS and applying modelling techniques for energy efficient
operation and ensure thermal comfort for occupants. The research has been conducted in existing office–
didactic building within the campus of Wroclaw University of Technology in Poland.
Keywords
BEMS, buildings, thermal comfort, energy efficiency, modelling
1
Introduction
Building Management Systems (BMS) integrate Building Automation Systems (BAS) in
order to secure the correctness of their work and their cooperation for providing comfort
parameters. The proper Energy Management Systems (EMS) administer the energy supply
and general building policy. EMS include not only measuring, monitoring and control of
energy supply and consumption, but also energy media consumption in particular installations
and the whole building. Modern technologies makes it possible to link the controlling and
supervising function in one computer system. Such an extended system is a technical
infrastructure and an energy computer management system known as a Building Energy
Management System (BEMS). The integration of all BAS in one system guarantees the
effective energy management, therefore achieving the energy-saving effect and the reduction
in energy consumption without lowering the comfort and security in the whole structure [4].
Mathematic models of controlled objects such as buildings, systems or plants are widely
used in planning and operation of modern automatic control and BEMS structures. The
complexity and usage of a model changes depending on the needs and capabilities [2, 5]. As
well as simple static models, the complex numeric models are in use, simulating the dynamic
response of the controlled object, with disturbances taken into consideration. Building energy
models are used for energy demand modelling, selecting and simulating the energy-saving
activities with the anticipation of their effect, as well as in the process of energy management
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Advanced Application of Real-time Integrated Building
and control [6]. The usage of building dynamic energy simulation in BEMS ensures obtaining
the optimum comfort parameters against the least possible energy consumption. Hence the
application of a BEMS emulator linked to a real BEMS system (Fig. 1) is the right solution.
The concept involves the use of a real-time numeric simulation of the building’s response to
an automatic control based on the constantly updated information from the sensors’ readings.
Each control reaction is preceded by a simulation of consequences of different regulation
algorithms, while the system will automatically choose the best operation scenario (for
comfort maintenance, energy use, safety, etc.)
EMULATOR
Calculation
data
Application software
of the partial
algorithms of energy
management in the
building, on the level
of the operator
stations and system
controllers
One device (computer)
Model
Mathematic
model
matematyczny
System
Sterownik
controller
obiektowy
System
measurement
Interface
Interface
Simulation
results
Stacja
BEMS operator
operatorska
station
BEMS
System
Sterownik
controller
obiektowy
System
measurement
System
Sterownik
controller
obiektowy
System
measurement
BEMS SYSTEM
Fig. 1. Emulator usage diagram in a BEMS system [1].
BEMS emulators will allow to test the BEMS algorithms for arbitrary input data and
emergency conditions; enable the examinations and tests of a BEMS itself, where the system
reactions to the modelled parameters and events are checked; help during the BEMS purchase
selection, in procedures of system optimum parameterization and for BEMS adaptation to the
object [3].
2
BEMS System in a Wroclaw University of Technology (PWR) Building
Within the scope of the research work there has been a model procedure of BEMS system
introduction in an existing building and a concept of numeric building model in the
management process of technical infrastructure and energy in the building was produced. A
BEMS research system has been built in an existing PWR building (Fig. 2) to examine the
produced algorithms and verify the simulation results. The system has integrated the BAS
systems of central heating installations, heating stations, domestic hot water and circulation,
air handling units, research installations and scientific laboratories.
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
AHU
T
W
S
SOLAR
PLATES
T
LAB
S
Oper.
stations
HEATING
STATION
STATION
TRAFO
HEATING
STATION
T
HEATING
STATION
- oper. station
T
HEATING
STATION
- BAS
S
- solar sensor
T
- outside temp. sensor
W
- wind sensor
Fig. 2. BEMS in the PWR building [1].
Fig. 3. EDSL - TAS model construction stages [1].
The building (Fig. 2,3) combines offices and educational features, therefore there is a great
variety of rooms assigned for different purposes, comfort parameters, character of use and
energy needs: auditoriums, laboratories, staff rooms, administration offices, libraries,
technological halls, technical spaces, lavatories, staircases, corridors, unheated rooms and
others. The way in which the building is operated is precisely related to the students’ weekly
timetable and the academic year. There are evident daily, weekly, semester and annual energy
consumption profiles. Hence the energy consumption is mainly related to the users’ presence
and activities (Fig. 4).
The amount and type of energy used by the building depends on many factors including:
the geometry of the building, its energy consumption, the number and type of energy
installations in which the building is equipped, and the way it is operated. The numeric energy
model of the building was used to look for energy-saving activities in the control and energy
management process. The adapted simulation computer program – EDSL TAS [6, 7] was
used to build and pre – parameterize the numerical model, imitating the localization and
geometry of the investigated building (Fig.3), its technical equipment and energy
characteristics.
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Advanced Application of Real-time Integrated Building
New Year’s Eve
Easter
New Year’s
Day
st
15th Aug.
rd
1 -3 May
Corpus
Christi
Christm.
11th Nov.
1st Nov.
electric energy, kWh
1600
vacation
1200
800
400
0
Jan Feb Mar Apr Mai Jun
Jul Aug Nov Oct Nov Dec
Fig. 4. The annual variability of daily electric energy consumption in the C-6 building [1].
3
Results related to the investigation on the C-6 Building
In the investigated building there was a reduction in electric and thermal energy consumption
gained in heating, ventilating and cooling (HVAC) systems due to the usage of a building
energy numerical model. The energy management procedures had included among others: the
temporary heating reduction and cut-off, temporary switching off of hot water installation and
circulation, air-conditioning units program control, energy peak management in particular
installations, the automatic starting and ending of heating season, optimum start/stop and
initial start. These algorithms were taking into consideration not only the influence of wind
speed and solar radiation, but also the energy consumption limits.
3.1
General Energy Consumption in the C-6 Building
Thermal energy in the C-6 building is used for heating, ventilation and hot water preparation
with circulation. On the basis of BEMS measurements there was a consumed heat quantity
register made in the investigated building, during the heating 2003/2004, 2004/2005 and
2005/2006 seasons. The savings gained over three years reached 15% of total energy
consumption of the building (Fig. 5). During the research period there were no thermomodernization work done in the C-6 building. The obtained savings came only from the
realization of the installation of energy-saving control and energy management algorithms by
the BEMS.
174
Zużycie energii
cieplnej, GJ
Thermal energy
consumption,
GJ
The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
6000
105%
100%
Zużycie consumption,
energii cieplnej,GJ
GJ
Energy
Wartość procentow
Percentage
value a
5000
4000
100%
95%
92%
3000
90%
85%
2000
85%
1000
80%
4904
4493
4185
2003/2004
2004/2005
2005/2006
0
75%
Fig. 5. Heat consumption in the C-6 building over three consecutive seasons [1].
3.2
Periodic Hot Water Installation and Circulation Cutoff
0,04
200
Rozbiór
c.w .u. dm3
Water
consump.,
dm3
Energia energy,
cieplna GJ
Thermal
GJ
0,03
150
0,02
100
0,01
50
0
WaterRozbiór
consumption,
dm3
c.w.u., dm3
Energia, GJ
Energy,
The C-6 building is operated periodically during the day. At night hours there is always only
one security person present, while the working circulation system causes constant thermal
energy loss (the average power is 16 kW). Therefore, there was a need for introduction of a
time control program for switching off the hot water preparation and circulation during the
out of the building operating hours with the optimization of the morning installation initial
start (Fig. 6). There was hot water structure operation analysed within the year and there were
variable energy-saving quantities gained, depending on the monthly hot water consumption –
the lower consumption, the bigger is the saving. There was an average of 27% of thermal
energy saved during the year. Additionally, during the night hot water system cutoffs the
circulation pump was stopped, which has made a further saving of up to 29% of the electric
energy being used by the pump.
0
12 13 14 15 16 17 18 19 20 21 22 23 00 01 02 03 04 05 06 07 08 09 10 11 12
Godzina
Hours
Fig. 6. Optimum algorithm of the hot water system work management [1].
4
Summary
In the process of building energy management, numerical building energy models should be
applied. Correctly parameterized model constitutes the basis for the current control process
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Advanced Application of Real-time Integrated Building
realization and energy management in a building; it also enables simulative search and
evaluation of energy-saving actions before their implementation in an existing structure.
According to specific needs simple numerical models under set conditions, dynamic models,
simulators or emulators can be used. The best results are received by the usage of complex
simulative models while taking into consideration the building dynamics and the influence of
the outside and inside conditions on the building energy balance. The produced model
concept of a BEMS system anticipates a real-time numeric simulation of building response
applied to automatic control, on the basis of information constantly updated by sensors
readings. Each control reaction is going to be preceded, in an interactive mode, by the
simulation of consequences of different control algorithms realization, and the system is
going to choose the best action scenario (for comfort maintenance, energy consumption,
safety, etc.). The authors’ produced a out structure recognition algorithms, energy modelling
and digital control for energy-saving in any office building possible by means of available
hardware and programming tools on the market.
References
1. Jadwiszczak, P., Building Energy Management Systems in office buildings, PhD Thesis
(2006), Wroclaw University of Technology, Wroclaw (2006).
2. Grabarczyk, C., Models in technical Science, International Conference “Problems in
Environmental Engineering on the threshold of the new century”, Publishing House of
Wroclaw University of Technology, Wroclaw (2000), p. 185-196.
3. Kärki, S., Development of emulation methods, Technical Research Centre of Finland
ESPOO (1993), VTT Tiedotteita - Meddelanden - Research Notes : 1514.
4. Syposz, J, Possibilities of decreasing building exploitation costs by using energy and
installation management systems, Instal No 10, Warsaw (2002), p. 2-10.
5. Zawada, B., Possibilities of accuracy estimation of simulation programmers on a base of
auto-correlation function, The 9-th International Conference of Air Conditioning & District
Heating, Wrocław (1998), p. 565-570.
6. U.S. Department of Energy (DOE) website: www.eere.energy.gov
7. Environmental Design Solutions Limited Ltd, United Kingdom, website: www.edsl.net
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Section 3:
Technologies for
Intelligent Building Services
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Technologies for Intelligent Building Services
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Use of Wireless Sensors in the Building Industry-Sensobyg
Claus V. Nielsen1, and Henrik E. Sørensen1
1
Concrete Centre, Danish Technological Institute,
DK-2630 Taastrup, Denmark
{Claus.V.Nielsen, Henrik.Erndahl.Sorensen}@teknologisk.dk
Abstract
The use of sensors for monitoring material properties and structural health in buildings and civil structures yields obvious
technical and economical advantages for building owners and for the society. The repair and maintenance of buildings and
structures are typically performed only on the basis of a visual inspection, sometimes combined with a more thorough
technical survey, where a few properties related to durability and strength are measured. Such tests are often destructive.
Due to the recent developments in wireless technology a good basis has been formed for further development of the sensor
technology for monitoring of structures and buildings. Wireless sensor systems are expected to drop in price which makes
them interesting for the building industry.
A Danish consortium titled “SensoByg” addresses the use of wireless sensors in the building industry. It is a three year
national project comprising 18 partners from industry and academia. The scope is to develop and demonstrate the advantages
of using monitoring systems based on embedded, wireless sensor technology and intelligent support systems for decisionmaking. The main focus is placed on wireless monitoring of moisture and temperature in buildings and large constructions. A
few examples of applications are given in the paper.
Keywords
Wireless, moisture, relative humidity, maturity, durability, maintenance.
1
Introduction
The Danish Ministry of Science, Technology and Innovation has recently granted a R&D
project to the building industry in Denmark. The project is titled SensoByg and its full name
is "Sensor based surveillance in construction". SensoByg started in March 2007 and it will be
running for 3 years until 2010 with a 4 M€ budget. The Ministry supports half the budget and
the industrial partners are obliged to deliver the other half in terms of working hours and
consumables.
The Danish Technological Institute is acting as the overall project manager for the 12
industrial partners and 6 R&D performers. The latter includes Aalborg University (building
physics), Technical University of Denmark (wireless signals and radio wave technology),
Alexandra Institute (software architecture for sensor networks), Lund University (moisture in
building materials), Aarhus University (software systems and computer science) and Danish
Technological Institute (sensor technology, concrete technology).
The industrial partners include
• Four building owners (or representatives) including the Danish Road Directorate and the
Fehmarn organisation responsible for the future Denmark - Germany link.
• Three concrete manufacturers (working with precast as well as ready mixed).
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Technologies for Intelligent Building Services
• One software developer, one consulting engineer and two companies working with sensors
for the construction and building industry.
The mix of participants should ensure that all aspects of sensor applications in buildings as
well as in civil structures are taken into account. The use of monitoring systems to survey
structures is not new. However, such systems are often not selected because of the need for
wiring and therefore wireless applications seem advantageous. The literature clearly shows an
increased interest in applying wireless sensor technology into the building industry [1-5]. It is
a clear belief that this trend will increase further and that it will provide better quality
buildings in the long term. Until now the activities are mainly revolving around indoor
climate control where sensors are used to determine the need for heating/cooling and
ventilation of buildings [2]. Such systems are of great help during operation of a building
ensuring an optimised energy performance. Recently interest is growing to measure the
conditions within the structures as well [3-5]. Thus, by combining existing sensor technology
with emerging wireless technology. When wireless sensors are embedded behind plaster
boards, timber frames, concrete slabs and steel there are a few difficulties since these sensors
are impossible to access once they have been placed. It is the main purpose of SensoByg to
exploit the opportunities and to develop robust, reliable systems for monitoring buildings,
civil structures and building materials by means of wireless embedded sensor technology.
It is outside the scope of the project to develop the next generation of sensor technology, e.g.
passive sensors and optical sensors. Focus is placed on the systems handling the sensor data
providing decision making tools for the building owners the building operators and the
contractors. It is expected that sensor prices will drop significantly in the near future and
thereby pave the way for a more extensive use in the building industry and thus, creation of
intelligent building materials. Therefore, the need for plausible systems to handle such sensor
signals is obvious and this is the core focus of SensoByg. The project also focuses on the
challenges to develop an embedment technique for the sensor so that it is able to survive the
alkaline environment of concrete and installation techniques being robust enough to survive
on the building site conditions.
The activities within SensoByg are strongly associated with the monitoring of moisture in
terms of relative humidity (RH) because moisture is almost always the driving force when
damages on buildings and building materials are considered. Moisture governs the durability
of concrete and it controls the risk of corrosion. Inside buildings moisture is associated with
growth of fungi and degradation of organic building materials. Furthermore, excess moisture
is responsible for health problems within houses. These effects are further enhanced by the
increased demands for insulation and tightness of modern buildings to preserve energy.
2
Organisation and Content of SensoByg
SensoByg is organised in 5 technical focus areas and 4 demonstration projects (Fig. 1). Two
focus areas (wireless sensors and coupling/interaction) develop the sensors to be applied in
the project including the signal technology and the antenna design so that wireless signals are
possible from cast-in sensors in heavily reinforced structures. Sensors are also produced for
the demonstration projects and the other focus areas.
A third focus area (encapsulation and embedment) develops techniques for embedment of
sensors and protection of the sensor electronics against water and concrete slurry. Both cast-in
sensors and post-installation are considered (Fig. 2). The robustness towards building site
environment, vibration equipment etc. is going to be investigated.
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The two last focus areas (decision support and system architecture) are developing a generic
concept for sensor networks and the end-user tools to be implemented in order to use the
wireless signals in an appropriate way in the building industry.
Fig. 9. SensoByg organization. Left: the four demonstration projects. Right: the five focus areas.
Sensor unit
with battery
Rubber
sealing
Fig. 10. Example of sensor encapsulation prepared for post-installation in bored hole.
Designed by Danish Technological Institute.
In order to ensure that all relevant applications are included in the considerations the
industrial partners are distributed in the demonstration projects and in the focus areas. The
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demonstration projects are meant to document the results of the work and to gain experiences
outside the laboratory. The split between the four demonstration projects are:
• Moisture in houses and buildings. Monitoring of moisture and temperature in critical
building elements where water damages are known to occur, e.g. bathrooms, roofs and
basements. The decision making is based on moisture together with knowledge of critical
moisture levels for growth of fungi and mould. Monitoring is both useful during construction
and a couple of years after construction and then again after say 30-40 years when
degradation of the climate shell is progressing and the risk of moisture related damages
increases.
• Large structures are mainly civil structures such as bridges and tunnels with 100+ years of
service life and operating in aggressive environments. But other large structures of steel are
also included. Sensors may be useful to monitor the critical areas for strength and durability
both during construction (short term) and over long term considerations of maintenance. An
example is given in section 4.
• Precast concrete elements are focusing on the concrete production phase, where the precast
plants use temperature simulations and temperature measurements to assess the correct time
of formwork stripping or prestressing. The decision tool should be able to help the workers to
decide when the precast elements are ready to be put on the stock yard. Furthermore, the
system could be useful to control the curing conditions with hot steam curing or electrically
heated form tables. In some cases it is also necessary to know the internal humidity in
concrete wall elements prior to painting. These data are only interesting during the building
process (short term). See more in section 5.
• Moisture in the construction phase for ready mixed concrete. During construction there is a
need to dry out some of the excess moisture from concrete (and other building materials). If
the concrete is not dried sufficiently the finishing works such as flooring and painting may
turn unsuccessful. Measuring of relative humidity in concrete is complicated and there is a
strong need for a more simple system. Wireless relative humidity sensors may be the solution
where contractors can monitor large castings continuously in order to determine when the slab
is ready for applying flooring. See more in section 5.
3
Sensor Type
As mentioned previously SensoByg is not focusing on the development of sensor technology.
The sensor that is meant for cast-in applications in the demonstration projects is illustrated in
Fig. 3. It is protected in a plastic casing with dimensions 2x3x5 cm so that only the sensor unit
is in contact with the environment. The sensor unit is a commercially available type from
Sensirion registering both relative humidity (RH) and temperature. In order to avoid fluid
water or cement paste to enter the sensor unit an appropriate material is used to block water
molecules but allowing water vapour to enter. Different materials are being tested and no final
solution is chosen yet.
The sensor transmits its data with a radio frequency of 433 MHz and the signal is received by
a reader box which again may store it until it is transmitted via GSM to a server where it is
accessed by the end-user.
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Micro computer and radio
transmitter
Battery
Sensor unit
Antenna
Fig. 11. Sensor layout to be fitted in 2x3x5 cm plastic casing. Sensor measures relative humidity (RH) and
temperature. Designed by Sensor Innovation Lab at Danish Technological Institute.
4
Application in Highway Bridge Repair Project
During the summer of 2007 a preliminary application was installed in connection with a
highway bridge repair project under the auspices of the Danish Road Directorate (Fig. 4). The
repair was typical for Danish concrete bridges where the waterproof membrane under the
asphalt pavement becomes defect after 20-40 years of service life. Then water gets access to
the reinforced concrete bridge deck from above, bringing harmful chlorides to the concrete
and increasing the risk of corrosion. After the removal of the asphalt and of the old damaged
concrete the bridge deck concrete is renovated, followed by new waterproofing membrane
and layers of asphalt pavement. The whole operation is carried out in two phases in order to
minimize the traffic disturbance.
A total of 5 wireless moisture sensors corresponding to the one shown in Fig. 3 have been
installed in small box outs directly under the membrane. Each sensor is equipped with extra
batteries in order to ensure up to 30 years battery life (Fig. 4 and 5). The five sensors are
installed along the bridge deck gutter line over a length of 30 m. Their purpose is to monitor
whether the membrane starts to leak and indicate the time of rehabilitation. It is recognized
that the sensors are probably not going to last 30 years due to limited life of battery elements
but they will give valuable information on the practical aspects on installation and embedment
techniques. It is also demonstrated how the sensor survive the heat impact from hot bitumen
during application of membrane and hot asphalt.
The sensor signals are transmitted every hour to a reader, which is placed at the bridge. The
reader box is equipped with a solar panel in order to provide sufficient energy to receive and
store the sensor signals and subsequently transmitting the signals to an internet server by
means of a GSM modem. In that way it is independent of the public electricity supply.
Results from the first few weeks of operation are depicted in Fig. 6. A sampling frequency of
one per hour may not be suitable for real applications since the data amounts get huge and the
battery is used every time a signal is sent to the reader box. However, in the preliminary tests
we are eager to obtain proper data rather than optimizing battery life. Furthermore, the data
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signals from the sensor the farthest away from the reader box are not always picked up due to
the signal conditions on the site in general and on the signal distance of 30 m in particular.
Thus, it is nice to have a rather high sampling rate so that the data are sufficient for
evaluation. In real applications a sampling frequency of once every week may be sufficient.
It is expected that in case of a leaking membrane the relative humidity in one of the sensors
will increase abruptly, being an indication of water penetrating the membrane.
Fig. 12. Left: Preparing repaired bridge deck for new waterproof membrane. Right: Sensor (black box) with
extra battery package (grey box).
Fig. 13. Box out in bridge deck where the sensor and battery box are installed and a protection lid is added on
top. Ready for applying the waterproofing membrane.
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Highway bridge repair, SensoByg, Hedehusene
90
Relative humidity [%]
85
80
75
70
65
E7E7E74C
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55
30-10-2007
25-10-2007
20-10-2007
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30-09-2007
50
Fig. 14. Diagram of relative humidity measured in the five sensors located right under the waterproofing
membrane.
5
Applications for Concrete Production
Precast Concrete. Another important application of moisture sensors in the building industry
is during production of concrete. At a precast plant the production cycle should be as fast as
possible in order to exploit the production equipment. Therefore, the precast producers
sometimes add heat to the concrete curing process in order to speed up the hydration process
so that the elements may be removed from the formwork and put into the stock yard.
Hydration of concrete is a chemical process strongly governed by the temperature. At the
same time the hydration process itself produces heat corresponding to about 100 MJ pr. m3
concrete.
The maturity concept of concrete combines age with temperature [6]. Thus, if concrete is
cured at say 10 °C in 1 day it corresponds to ½ day maturity and if the curing takes place at 20
°C the maturity and the real age is identical since 20 °C is used as reference. One day curing
at 35 °C would mean 2 days maturity. Knowing that strength and maturity are closely linked
it is obvious that the concrete producer has an advantage in heating the concrete to say 50 °C
during its early stages of hydration in order to obtain rapid strength gain. The effect is
especially advantageous and necessary during the cold season and especially in cold climates.
The precast producers should obtain wireless temperature readings from within the concrete
elements. In that way they could optimize the curing process and a decision tool should be
developed so that the time of formwork stripping is predicted in advance based on the weather
forecast and online temperature measurements. The system could also be used to control the
heating so that the heat generated by the concrete itself is utilized.
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Ready Mixed Concrete. In connection with in-situ castings there may be a need to monitor
the concrete temperature in a structure for a number of reasons. Firstly, it may be used to
assess the maturity of a concrete pour in order to decide time of formwork stripping or
prestressing just like in the case of precast concrete above. Secondly, temperature differences
between the core of a casting and the surface should not exceed a certain limit due to the risk
of early-age thermal cracking. This is especially a concern of massive structures. And thirdly,
temperature reading on in-situ may be suitable to control active measures such as embedded
cooling pipes or heating wires or it may help to warn against freezing conditions prior to
casting.
Another important aspect of ready mixed concrete is its moisture content. During hydration
the cement reacts chemically with the mixing water but even after complete hydration there is
still say 110 litres of physical water per m3 in the concrete air pores. If the concrete is applied
into a slab on grade and the floor material is a moisture sensitive material, e.g. wood or glued
plastic flooring the relative humidity in the concrete should not exceed say 85 % relative
humidity. Or else the glue loses its adherence and the basis for growth of fungi is there. For
conventional concrete for houses this means, that there is an excess amount of water of
approximately 30 litres/m3, that needs drying out before flooring. During the cold season
concrete drying is a very slow and difficult process, requiring a lot of energy. Drying out of
concrete will often require 2-3 months with controlled drying climate, i.e. moderate
temperatures and fairly dry air. Furthermore, a building site is always subject to rain and other
sources of water that may add to the built in mixing water of concrete (Fig. 7).
In Denmark the floor contractor must document that the moisture level is below the threshold
value before he is supposed to place the flooring. Conventional measuring of relative
humidity in a floor slab is by definition time consuming and difficult:
• One way of doing it is in a drilled hole where a RH sensor is placed so that the relative
humidity is registered in half thickness of the slab. The sensor should be left in the hole for
at least a day in order to obtain moisture equilibrium between the concrete pore system and
the hole. Then the operator has to return the next day to read it. At a building site it is not
safe to leave expensive equipment such as a RH sensor in place for several hours. Also the
readings may be sensitive to temperature variations.
• Another way of doing it is by taking out a sample of concrete from the slab in half
thickness depth. This sample is then sealed in plastic bags and taken to a laboratory where
it is brought in contact with a RH sensor.
Both methods are destructive and they need special equipment such as hammer drill. It is not
normal to take more than a single sample from even a large concrete floor and the variation in
moisture content across the floor area is not considered. Furthermore, the methods require
skilled persons to condition and handle the sample, making it an expensive method.
Furthermore, this person is never the same as the one who is running the building site.
If there was a possibility to embed a number of wireless RH sensors (similar to the one in Fig.
3) in a certain area of newly cast concrete the contractor himself would be able to monitor the
drying process continuously and make decisions on when to bring in extra heating, ventilation
or air driers. He would also be able to plan his work better and to control the interfaces
between the different labor groups on the site. At the end the floor quality would be better and
the need for expensive repair works is avoided. Furthermore, it becomes easier to plan the
work according to the deadlines imposed by the contract.
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Fig. 15. Rain adds water to the concrete on a building site making it hard to dry it sufficiently especially in the
cold season. A low quality concrete may absorb 10-20 litres/m3 if it is exposed to rain during its very early life.
The rain water is not stopped until the building is closed with (interim) windows and doors and a watertight roof
structure. The lower storeys of a building are often left exposed to the weather during half a year or even more.
6
Conclusions and Recommendations for Further Work
The conclusions are still few since the SensoByg project is in its start-up phase. However,
from the preliminary work and discussions the following conclusions are drawn:
• There is a great potential for improving the quality of building structures and civil
structures by means of wireless sensors embedded into the building materials, e.g. cast into
concrete. The benefits are plenty ranging from more durable structures and improved
indoor climate.
• Wireless sensor technology has already made its impact on monitoring of indoor climate
though ventilation systems, window openers and so forth. However, SensoByg is working
to implement these technologies so that the sensors are embedded in the structures as well.
• Full-scale tests on a highway bridge have shown that it is possible to measure relative
humidity and temperature through concrete and asphalt. However, it is also recognised that
the wireless signals are sensitive to various external conditions and that the antenna needs
optimisation.
Throughout the preliminary tests a couple of issues have been identified that still need
attention during the course of the SensoByg project. First of all the development of proper
methods for installation of sensors in the aggressive environment of newly cast concrete are
mandatory. The sensor casing should be robust enough to resist the impact of falling concrete
as well as impacts from the casting equipment and vibrators. At the same time it should allow
water vapor to enter the sensor unit but not fluid water. The electrical circuits also need to be
protected from the moist environment and it should be able to withstand freezing temperatures
as well at hot conditions.
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Secondly, methods to fixate the sensor properly should be described, both prior to and during
casting. A method for post-installation is also needed for concrete but also for other building
elements such as stud walls, bathroom walls and wooden floors. For certain applications it
may not be important to know the exact location of the sensor but for moisture measurings in
a newly cast concrete slab on grade the position is important. If the sensor is measuring to
close to the concrete surface it underestimates the relative humidity and vice versa.
Another important issue is the wish to develop an end user interface that is both versatile and
simple to use. The user should be able to add different features such as prediction of drying
rate of concrete under various conditions. There will also be need for handheld readers so that
the sensors can be read without being connected to the internet. Finally, it is very important
that the system includes print outs of documentation to be handed over to the building owner
when he accepts the building.
Furthermore, the demonstration projects will give valuable experiences of wireless sensor
applications under realistic conditions. These experiences will include radio signal strength,
disturbances from other radio signals, precision of available sensor units compared with
conventional methods. It is important that the sensors are accurate and stable since they are
impossible to recalibrate or maintain when they are cast into a concrete structure.
Acknowledgements. The authors would like to thank the partners in SensoByg. For the
highway bridge the assistance of Ramboll and the Danish Road Directorate is gratefully
acknowledged.
References
1. Grosse, C.U., Kruger, M., Glaser, S.D.: Wireless Acoustic Emission Sensor Networks for
Structural Health Monitoring in Civil Engineering. ECNDT 2006 Proceedings, Tu.1.7.3
(2006)
2. Kintner-Meyer, M., Conant, R.: Opportunities of Wireless Sensors and Controls for
Building Operation. Energy Engineering Journal, Fairmount Press Inc., Vol. 102, 27-48
(2005)
3. Grasley, Z.C., Lange, D.: A New System for Measuring the Internal Relative Humidity in
Concrete. Cementing the Future, ACBM (2004)
4. Sjöberg, A., Blomgren, J.: Moisture Measuring with Wireless Sensors in the Building
Industry. (in Swedish) Lund Technical University, TVBM-3123 (2004)
5. Sjöberg, A., Blomgren, J., Erlandsson, M., Johansson, C.: Wireless Sensors in the Building
Industry – a field study of two sensor network systems for moisture and temperature
monitoring. (in Swedish) Lund Technical University, TVBM-3139 (2007)
6. Nielsen, C.V.: Modeling the Heat Development of Concrete Associated with Cement
Hydration. American Concrete Institute, Special Publication SP-241 (2007) 95-110.
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Wireless Sensor Networks for Information Provisioning for
Facilities Management
1
1
1
Apostolos Malatras , Abolghasem (Hamid) Asgari , and Timothy Baugé
1 Thales Research and Technology (TRT) UK,
Worton Drive, Worton Grange Business Park, Reading RG2 0SB, UK.
{apostolis.malatras, hamid.asgari, timothy.bauge}@thalesgroup.com
Abstract
A major critical aspect of efficient facilities management is that of monitoring the surrounding environment and collecting
precise and synchronized information regarding the status of the facilities. The primary source of facilities related
information is sensor nodes deployed across the building. Lately Wireless Sensor Networks (WSNs) have emerged, bearing
significant benefits as far as monitoring is concerned, since they are more cost-efficient compared to wired sensor solutions
and allow for flexible positioning of the sensors. The majority of existing building management systems is tightly coupled
with the sensors that they utilize, restricting their extensibility. In this paper we propose to exploit a Service Oriented
Architecture for developing an enterprise networking environment that is used for integrating facilities and building
management systems with other operational enterprise functions for the purpose of information sharing and monitoring,
controlling, and managing the enterprise environment. The WSN is viewed as an information service provider not only to
building management systems but also to wider applications in the enterprise infrastructure. We provide specification and
implementation details of the proposed WSN architecture.
Keywords
wireless sensor network, service oriented architecture, web services, facilities management
1. Introduction
Building systems, such as HVAC (Heating, Ventilation and Air Conditioning), security,
electricity systems, lighting, access control, resource monitoring and planning, etc., satisfy the
requirements of the occupants of the buildings in terms of desired functionality and comfort.
In their conventional mode of operation, these systems are managed independently, leading
thus to high operational costs, cumbersome overall management and increased level of
expertise required. Lately, there has been a paradigm shift towards architectures that allow for
integrated Building Management Systems (BMSs) and support building automation and
control under a unifying framework. This will enable the building manager to have a single
point of interaction to control facilities in an integrated manner.
One of the most important parameters regarding facilities management is accurate monitoring
of the building system and its surroundings, usually performed by sensors dispersed
throughout the premises. The emergence of Wireless Sensor Networks (WSNs) has brought
significant benefits as far as monitoring is concerned, since they are more cost-efficient
(because of the lack of wired installations) compared to their wired counterparts, while
additionally they allow for flexible positioning of the sensor devices. Existing building
systems are tightly coupled with the sensors they utilize, restricting the generic extensibility
of the overall architecture. In line with established move towards integrated enterprise
architectures, it is beneficial to consider the WSNs within that scope. The WSN architecture
should subsequently be designed in such a manner, so as to allow its straightforward
integration to the building enterprise infrastructure.
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The necessity therefore emerges to adopt a broader perspective regarding the overall
architecture of BMSs that will be open and extensible, allowing for dynamic integration of
novel or updated/advanced building services. Furthermore, the diversity of the offered
building services needs to be addressed, as do the evident scalability issues subject to the
particular building environment application domain. The overall building services architecture
should also realise a long-standing lifecycle view taking into account the needs of all
stakeholders, which in turn further motivates the need for design flexibility.
The most prominent approach towards an enterprise-wide, open framework, which satisfies
the aforementioned requirements, is that of Service Oriented Architectures (SOAs). In the
case of SOAs all architectural elements are decoupled and considered as service providers and
consumers. Service discovery and offering is performed in a dynamic manner, ensuring thus a
generic and extensible design. WSNs can be regarded as service providers related to building
information monitoring and should therefore be considered within the scope of the facilities
management SOA, which promotes the concept of dynamic, coordinated and distributed
building services management.
This paper presents a general framework to integrate WSNs in an overall SOA regarding
facilities management. A thorough requirements analysis for the building domain is
performed and the respective functionality is mapped on specific elements of the proposed
architecture, while we also provide relevant specification and implementation details.
The remaining of this paper is structured as follows. After this brief introduction, Section 2
reviews related work in the area of service-oriented frameworks for the web enablement of
sensor networks as well as building services and facilities management in general. Section 3
discusses the proposed WSN architecture, including analysis of the relevant requirements that
motivate our work. The specification of the proposed architecture is given in Section 4, while
Section 5 concludes the paper and discusses planning for evaluation and other issues for
future work.
2. Related work
Automating the facilities management domain by enabling the employment of intelligent
operations and of unsupervised management and control has attracted significant research
interest over the past years [1]. Successful examples of individual automated building services
and systems exist, e.g. HVAC controls, security systems, fire alarms, etc. Their integration
and the adoption of a building-wide degree of automation have nonetheless not been reviewed
thoroughly, despite the benefits that such approaches would bring to all building stakeholders
[8]. There is an evident lack of holistic, integrated building management solutions [3]. The
approaches that have been most profoundly established, i.e. cross-protocol gateways and
standard communication protocols have not satisfied the desired expectations and have had a
narrow applicability field.
More recent approaches are exploiting and developing middleware technologies to support
building automation systems and building services at a higher layer [5], as a response to the
firm necessity for integration. Such novel approaches for integration do not intend to
substitute proprietary, low-level building automation systems. The focus is on providing
smooth integration of diverse systems and services by using the notion of middleware
abstraction, i.e. the individual building systems continue to operate as originally configured
by their manufacturers, yet middleware wrapper applications are used to facilitate interaction
and interoperability. Most of the aforementioned middleware-based solutions bear inherent
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problems, which are predominantly focused on the fact that the proposed solutions are based
on proprietary, closed technologies that hinder interoperability.
One should also consider the importance of incorporating BMSs and automation systems in
the overall enterprise-networking environment, an aspect that has been neglected in most
middleware-based solutions. There has been a wider spectrum paradigm shift towards the
adoption of enterprise-wide architectures, which take into account cross-layer interactions and
business objectives alongside system requirements. It becomes therefore evident that it would
be beneficial to exploit such enterprise architectures, driven by the SOA paradigm, in the
building management realm [15]. Under this prism, IT and building management convergence
is logically promoted, enabling open, flexible and scalable enterprise-wide architectures.
The synergy created by combining building infrastructure and data communications reduces
operational costs and creates new service opportunities [6]. The main implication of this
synergy, regarding facilities management is that it provides BMSs and building automation
and control systems with access to additional information that will enable the building to be
used more effectively. This information as far as the automated building control semantic
domain is concerned can be collected from a variety of sources i.e. sensors, ranging from
physically sensed data (structural, environmental, physiological, etc.) to electronic records
(building maintenance records and schedules, personnel profiles and calendars, etc.). [6]
WSNs as information sources facilitate sensor deployment and reduce costs, mostly through
the absence of wiring installation and maintenance [8]. Initial work on the area consisted of
cost-benefit analyses for the use of WSNs in building operations, compared to employing
their wired counterparts. These analyses were complemented with reviews of relevant
technological advances that highlighted the penetration and advantages of WSN approaches in
the building management domain [6]. Limited resources of WSN nodes were studied in [8] in
order to examine the feasibility of implementing standard concepts of building automation
systems, e.g. BACNet, in sensor platforms. This was deemed as possible, with limitations
nonetheless in their portability and ease-of-development.
Research work in the area of WSNs has moved from the traditional view of sensors as static
resources, from which data can be obtained, to the more innovative view of everything being
considered in a service-oriented perspective [9][10][11]. This allows WSNs to be regarded as
service providers, i.e. information services, and consequently more advanced, dynamic,
reusable and extensible applications and operations to be provided.
The benefits of exposing sensor networks as service providers in a generalized SOA
motivated the emergence of the SWE (Sensor Web Enablement) activity [9]. Amongst these
benefits one can identify that the underlying WSN complexity is hidden from higher-layer
applications, common operation reusability is ensured, scalability, extensibility and
interoperability are promoted, etc. Other research efforts build on SWE principles to propose
architectures for exposing WSNs as service providers in a SOA [11]. Our work takes
advantage of certain principles set out by SWE, such as abstraction, separation of operations
in reusable objects and applies them to the facilities management realm, also taking into
account the particular domain’s inherent characteristics, e.g. space categorization and
coexistence with existing BMSs. The Atlas platform [10] relates more closely to the approach
we plan to undertake. We distinguish ourselves from this work however, since we do not
utilize specific hardware platforms as Atlas does and hence allow for different and diverse
sensor platforms to be used.
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In the following we present our approach for the web enablement of WSNs for facilities
management, while in parallel we describe the requirements that drive our design.
3. Proposed WSN architecture
This paper provides a detailed architectural framework for WSNs to be integrated seamlessly
with enterprise applications over a SOA infrastructure, within the scope of facilities
management. An overall WSN architecture serves a multitude of facets such as:
•
Optimizes the information flow and accessibility, allowing all authorized systems and
applications, which require a given source of information to have shared access to that
information stream.
•
Increases the coverage, resolution and accuracy of the information awareness made
available to human and automated decision makers, by developing an information web,
which all systems and applications can access and exploit through standard interfaces.
•
Develops a new design approach to high-level facilities management applications, by
allowing composition of data, information and operational services into added value
monitoring and decision making support tools.
One fundamental concept to building management systems that is inherently bound to WSNs
is that of context awareness. We define as context of a system the set of information of every
nature that describes the system, influences system aspects and that is being affected by the
system’s operation, the ownership of which is not necessarily solely held by the system.
WSNs are the sources from where context information can be retrieved. The collection of
information sources from disparate sources throughout the building by appropriately
configured sensors is extremely beneficial to the building management system and necessary
for its proper operation. This information nevertheless has to be managed effectively. The
collected data from the sensors have to be translated into high-level contextual information
using context models. Context models are key to interpreting raw data into high-level
information that is useful to the application layer.
The functionality of the WSN architecture can be decomposed in two complementing aspects,
namely WSN services exposed to the enterprise architecture and WSN tasking to monitor
context information. The WSN architecture needs to be incorporated in the overall facilities
management SOA that we envisage and assume the role of service provider as far as data
collection and information management – in the sense of context awareness - is concerned.
This justifies the need for a WSN service interface to be defined and exposed to the SOA
infrastructure, in order to hide the complexity and heterogeneity of the underlying WSNs. The
architecture that we propose for this purpose has to additionally cater for the monitoring and
data management aspects that form its core functionality. These functional requirements are
addressed by a tasking middleware that is responsible for translating the high-level requests
for information as received from clients of the facilities management SOA into low-level,
WSN-specific data queries. The clients need not be aware of the WSN internal operations,
hence the importance of the tasking middleware.
When a facilities management service wishes to obtain specific WSN monitored information,
it accesses the respective WSN service interface requesting so. The WSN service assigns this
request to the tasking middleware that directly operates on top of the sensor nodes and
performs the actual data collection and possibly processing. The outcome of this operation,
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i.e. the corresponding sensed data, is then forwarded to the WSN service that posts the
processed information back to the original requester.
The WSN architecture is implemented over two sensor platforms, i.e. the sensor node and the
gateway, as explained in section II. The high level, layered, functional architecture of the
WSN is shown in Figure 4 for both the sensor node and the gateway.
The top layer is the enterprise middleware, which is only hosted on the specific gateways (and
all other enterprise platforms that participate in the SOA), exposing service interfaces to the
SOA. The tasking middleware, hosted on the gateways and the nodes, is located below the
enterprise middleware and takes care of node level tasking for sensing and processing.
The network service layer deals with the communication aspect of the sensor network. It
relies mainly on the radio/enterprise network interface components of the node services, and
provides the protocol stack functions above them. Network services can be designed in layers
following traditional OSI (Open Systems Interconnection), or TCP/IP layers.
Wireless sensor network
Node services
Sensor Node
Network services
Node services
Reprogrammability
Network services
Tasking
Gateway
middleware coordination
Security
Security
Tasking middleware
Reprogrammability
Enterprise
middleware
Gateway
Figure 4: WSN functional layered architecture.
The node services are the functions, which are local to the devices. Both sensor node and
gateway contain the same basic functions, namely processing, storage and radio. Although
these functional blocks exist in both sensor node and gateway, they are likely to have diverse
levels of capability in the two platforms. Gateways are not constrained in energy, have less
size constraints and therefore can have significantly higher computational and storage
capacity than sensors. The gateway additionally has an enterprise network interface, to
connect to the wider enterprise SOA. Sensors contain a number of additional node services,
not present in the gateway, such as sensing, power management and positioning.
Moreover, the security issues in WSNs have to be given explicit consideration, as this remains
to date an open issue. Reprogramming is also an essential but challenging task in WSN
management due to limitations in available resources and constraints in communication
capabilities. These two aspects are however outside the scope of our current work.
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Technologies for Intelligent Building Services
WSN – Zone 1
SGW
Gateway
coordination
interface
SGW
Gateway
coordination
interface
Gateway
coordination
interface
MGW
Tasking
middleware
interface
Gateway
coordination
interface
SGW
SGW
Gateway
coordination
interface
Gateway
coordination
interface
MGW
Tasking
middleware
interface
Tasking
middleware
interface
VGW
Enterprise
SOA
interface
Enterprise IP network
WSN – Zone 2
VGW Virtual Gateway
MGW Master Gateway
SGW Secondary Gateway
Figure 5: Scalability support in the proposed WSN architecture.
We assume that a building consists of multiple zones each one having a WSN dedicated for
its monitoring needs, as shown in Figure 5. One or more gateways are utilized to connect each
of these WSNs to the enterprise architecture. These gateways manage the nodes that are under
their zone of responsibility. The argument behind the concept of having more than one
gateway is our desire to provide a scalable and reliable architecture, while gateway
coordination is considered to ensure uniformity through an appropriately defined protocol.
Other applications nevertheless are unaware of the potentially numerous zones and hence
gateways in a building. The enterprise applications need a certain degree of abstraction from
the underlying complexity and the specifics of the zone/WSN assignments, and require a
single point of contact to WSN-related activity in the building as a whole. This is the reason
for introducing the notion of a prime virtual gateway. A back-up virtual gateway has also
been considered for stability and reliability reasons. The virtual gateway is aware of the
various WSNs available in a building and their respective gateways. When enterprise services
require interaction with the WSN architecture, this occurs through the relevant service
interfaces that are exposed at the virtual gateway, as shown in Figure 5.
4. Architecture specification
The WSN service interface is exposed in a greater SOA for facilities management. There exist
various service models, such as JINI, grid services, CORBA, Web Services (WS) etc. We
opt in favour of WS, the main reason being their wide-acceptance and the fact that they enable
easy and straightforward deployment of applications over enterprise networks, as required by
our architecture. WS are amongst the major technological enablers of SOAs and have
attracted significant research interest, due mainly to the fact that they are supported by wellestablished standards. WS constitute a means for various software platforms to interoperate,
without any prerequisite regarding platforms and frameworks homogeneity being necessary.
The WSN environment is essentially a collection of resources (i.e. sensors) that continuously
monitor their status (i.e. get measurements). We have therefore defined a REST-based
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(REpresentational State Transfer) style SOA to enable integration of the WSN with enterprise
services. REST-based WS lack the complexity of SOAP-based WS and form an open and
flexible framework, allowing scalable and dynamic resource monitoring.
WSN
WS
are
rooted
at
the
following
base
URI:
http://{hostname}/REST/{version}/. The {hostname} parameter must be
replaced with the name of the server hosting the WS. When a client wishes to interact with the
WSN architecture over the SOA, the client issues the appropriate HTTP method, namely
GET, POST, DELETE, PUT. The format of the resource representations used by the WSN
architecture has been formally described using an appropriate XML Schema Definition; space
limitations however avert us from presenting it in this paper.
The tasking middleware is the architectural entity that implements the functionality exposed
by the WSN service interface. The tasking middleware receives as input high-level service
requests (WSN queries) from enterprise entities via the enterprise networking architecture,
determines what data and processing are required to provide the service, tasks the relevant
sensor nodes to perform sensing and processing (sensor tasks), collects the resulting data and
finally responds to the original service request. The tasking middleware involves three
operations, namely service and location discovery and sensor data query/response. Figure 6
depicts the high-level view of the WSN architecture within the overall enterprise level scope.
WSN
Gateway
Zone 2
WSN
tasks
(802.11.15)
Zone 3
Virtual
gateway
Enterprise Service Bus
WSN
(802.11.15)
queries
REST- based WSN WS
Interface
Zone 1
Gateways’ communication network
(Ethernet, 802.11 etc.)
(802.11.15)
BIM
BMS
information
data
Figure 6: WSNs exposed in the proposed SOA.
The functional architecture of the tasking middleware defines operations for service/location
registration of the nodes to the corresponding gateway. Service and location discovery and
registration involve a series of actions and participating modules that occur upon bootstrap
and sensor initialization; we nevertheless limit the discussion on the data querying and
responding aspects of the tasking middleware due to space limitations.
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Technologies for Intelligent Building Services
Stores sensor tasks.
Sensor
Task
DB
Zigbee Network Handler
Masks underlying
connectivity to Zigbee
network and sends/receives
Zigbee messages.
Response Manager
1) Handle sensor task
reports.
2) Generate appropriate
client responses by
matching task reports to
client queries.
Task Filter
Filter redundant
sensor tasks.
Sensor Task Manager
Processes and generates
sensor tasks that were
derived from queries.
Query Manager
Processes queries
and cancellations
from clients
Data
Query
DB
Enterprise
Network
Handler
Node
DB
Building
Information
Model
Query Decomposer
1) Decompose a query
into sensor tasks.
2) Resolve domain
semantics to WSN
location semantics
Stores clients’ queries and maps
data query to sensor tasks.
Figure 7: Data query-response architecture specification (gateway).
Figure 7 depicts the tasking middleware architecture for data queries/responses and illustrates
the gateway’s functionality. The Query Manager is the main middleware module and is
responsible for listening to client queries regarding data collection through the Enterprise
Network Handler. It then contacts the Query Decomposer to generate tasks from the client’s
data query. This operation involves mapping from the high-level queries set by clients to the
low-level WSN specific sensing tasks (the Query Manager contacts the Node DB and the
BIM for node and building related information respectively). The Data Queries and the
corresponding list of task requests are stored in the Data Query DB and the Sensor Task DB
respectively, while the task requests are dispatched from the Query Manager to the Sensor
Task Manager. The Sensor Task Manager filters redundant tasks with the use of the Task
Filter and then sends the tasks to the appropriate sensor nodes through the Zigbee interface
[12][13] Network handler module that is responsible for communicating directly with the
sensors.
On the sensor side of the architecture (Figure 8), there is a Zigbee Network Handler to allow
for communication with the corresponding module of the gateway. It is this module’s
responsibility to send and receive Zigbee messages and forward them to the Task Processor,
which processes sensor tasks and stores them in the Task DB, while additionally it handles
task cancellations. Upon receipt of a new task request the Task Processor stores it into the
Task DB and then forwards it to the Task Scheduler in order to plan its execution. The Task
Data Manager performs the action specified in the task by allocating the necessary resources
and sampling the appropriate hardware sensors. Upon successful completion, the Task DB is
informed and updated with the relevant task data and the Data DB is updated with the derived
sensor data. A notification message (with data or an alarm report depending on the sensor
task) is sent back to the Zigbee Network Handler, to be forwarded to the gateway.
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Sensor node
Task Scheduler
1) Keep a schedule of
running tasks.
2) Generate an event
when task is due.
Task Data Manager
1) Samples hardware
sensors.
2) Generates data or alarm
reports depending on sensor
task, and sends to gateway.
1) Storage of
sensor tasks.
Task Processor
1) Processes sensor
tasks.
2) Handles task
cancellations.
Task
DB
Data
DB
1) Storage of
sensor data.
Zigbee Network Handler
Sends/receives Zigbee
packets.
Figure 8: Data query-response architecture specification (sensor node).
We have also specified the functionality required for query cancellations but space limitations
avert us from further elaborating on this topic. By using the specified architecture
implementation, sensor information is made available to BMSs and other information
consumers via the enterprise-based networking infrastructure.
5. Conclusion
We have discussed in this paper an architectural framework that enables the integration of
wireless sensor networks in an overall facilities management enterprise architecture. The
benefits that can be reached by utilizing service-oriented enterprise architectures are
numerous, hence the need to move towards such approaches. Reductions in cost, flexibility
and agility to respond to dynamic conditions are among the most prominent advantages that
can be observed.
We have discussed related issues and based on an extensive requirements analysis we have
provided a functional architecture and a corresponding specification for the proposed WSN
architecture. Security and reliability that are extremely important in the wireless domain have
been taken into account, while in parallel scalability and extensibility are also supported. We
elaborated on a service-oriented architecture to expose WSN-related information to the
overall enterprise architecture and detailed on the tasking middleware aspects that are actually
responsible for data collection and processing.
Our future work focuses on evaluating the proposed WSN architecture in our experimental
WSN testbed in order to validate the development efforts and furthermore to examine areas of
potential deployment of such an approach. One of the main aspects we plan on evaluating is
the use of this architecture in order to implement a building assessment tool as far as energy
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Technologies for Intelligent Building Services
efficiency is concerned. This is a highly significant and emerging issue regarding buildings
and is going to be our main area of research.
Acknowledgments. Work towards this paper was partially supported by the Commission of
the European Union NMP I3CON FP6 project, NMP 026771-2.
References
1. Snoonian, D., Smart buildings, IEEE Spectrum, Vol. 40, No. 1, pp. 143-159, 2005
2. Wang, S.W. and Xie, J.L., Integrating building management system and facility
management on internet, Automation in Construction, Vol. 11, No. 6, pp. 707-715,
Elsevier, 2002
3. Braun, J. E., Intelligent building systems – past, present, future, 2007 American
Control Conference, pp. 4374-4381, IEEE press, July 2007
4. Wang, S. Xu, Z., Li, H, Hong, J. and Shi, W.-Z., Investigation on intelligent building
standard communication protocols and application of IT technologies, Automation in
Construction, Vol. 13, pp. 607-619, Elsevier, 2004
5. Ehrlich, P., Guideline for XML/Web Services for building control, Proceedings of
BuilConn 2003, Dallas, April 2003, http://www.builconn.com/, accessed September
2007
6. Brambley M.R., Kintner-Meyer, M., Katipamula, S. and O’Neill, P. J., Wireless
Sensor Applications for Building Operation and Management, Web Based Energy
Information and Control Systems, pp. 341-367. The Fairmont Press/CRC Press, 2005
7. Ming, Z., Li-Ding, C. and Bu-Gong, X., A middleware framework for integrating
intelligent building systems based on the sub-system peer mode, IMACS Conference
on Computational Engineering in Systems Applications, IEEE, pp. 1766-1770,
October 2006
8. Österlind, F. Pramsten, E., Roberthson, D., Eriksson, J., Finne, N. and Voigt, T.,
Integrating building automation systems and wireless sensor networks, 12th IEEE
Conference on Emerging Technologies and Factory Automation, September 2007
9. OpenGIS ® Sensor Web Enablement Architecture, Editors: M. Botts, A. Robin, J.
Davidson, I. Simonis, OpenGIS Discussion Paper, April 2006
10. King, J., Bose, R., Yang, H., Pickles, S. and Helal, A., Atlas: A service-oriented
sensor platform, Hardware and Middleware to enable programmable pervasive
services, 31st IEEE Conference on Local Computing Networks (LCN), pp. 630-638,
November 2006
11. Moodley, D. and Simonis, I., A new architecture for the sensor web: the SWAP
framework, 5th Intl Semantic Web Conference, LNCS 4273, Springer, November 2006
12. IEEE Std 802.15.4-2003, Telecommunications and information exchange between
systems – Local and metropolitan area networks – Specific requirements – Part 15.4:
Wireless Medium Access Control and Physical Layer Specifications for Low-Rate
Wireless Personal Area Networks, 2003
13. ZigBee Specification 1.0, ZigBee Alliance, June 27, 2005, http://www.zigbee.org/,
accessed September 2007
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Life Cycle Information of Buildings Supported by RFID
Technologies
Frank Schultmann1, Nicole Sunke2
1,2
Chair of Business Administration, Construction Management and Economics, University of Siegen,
Paul-Bonatz-Str. 9-11, 57068 Siegen, Germany
{frank.schultmann, nicole.sunke}@uni-siegen.de
Abstract
Radio Frequency Identification (RFID) technology has attracted increasing attention of researchers as well as practitioners in
recent years. However it can be observed that the construction industry still lacks the application of innovative technologies,
such as the application of automated identification systems. Potential areas of application of RFID in construction are
revealed and a future prospective for the adoption of this technology in sustainable construction management throughout the
whole life cycle of a building is developed. Thereby, the relevancy of RFID can be seen especially in industrialised
construction, where RFID technology could be applied for the production of building components and parts and tracking
them from production to installation. Further potentials of RFID in construction encompass issues like the automation and
optimisation of facility management processes and monitoring of operating resources during occupation and operation of
buildings as well as environmentally sound deconstruction planning based on information gathered with RFID.
Keywords
Radio Frequency Identification, Construction Industry, Facility Management, Site Management, Product Identification
1
Introduction
Automated identification of objects enables the simplification and optimisation of processes
in a variety of applications. Examples of identification techniques are Bar Code and the Radio
Frequency Identification Technology (RFID). RFID is an Auto-Identification technology that
allows the unique identification of objects up to a distance of several feet. It has already been
established in rather simple applications like theft-secure in department stores for several
decades. In comparison to other Bar Code systems, the advantages of RFID are, for instance,
higher reading ranges, the non-necessity of line-of-sight between the reading device and the
transponder onto which the data respectively information is stored and the possibility to store
new data onto the transponder in dependency on the employed technique.
However, applications and research mainly focuses on the implementation of RFID in the so
called off-site production where it has already been proven to be successful. This comprises,
for instance, the automotive sector and the electrical and electronics industry in various fields,
such as anti-theft systems, tracking of products throughout the supply chain, and autoidentification of goods [1], [2].
Generally, production processes in construction are more complex than in ordinary make-tostock or manufacture-to-order production environments. Characterised by its design-to-order
production, the final assembly of the building takes place on-site and it remains there till the
end of its life time. In contrast to the complexity, it can be observed that the construction
industry still lacks the application of innovation and high end technologies, such as automated
identification systems, although the amount of materials and components as well as
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Technologies for Intelligent Building Services
information arising during the life time of a building and during the different phases of the life
cycle of a building are significantly higher than in traditional manufacturing processes.
In this paper potential areas of application of RFID in construction are revealed and
additionally embedded in the life cycle of a building. Thereby, special focus can be drawn to
the application of RFID in industrialized construction where it can be applied for the
production of building components and parts and tracking them from production to
installation. Hence, a future prospective for the adoption of this technology in sustainable
construction management throughout the life cycle of a building is developed. It is not
intended, however, to give a complete overview on all possible applications in construction as
done, for instance, by Wing [3] and Jaselskis and El-Misalami [4]. Instead, the prospective
encompasses issues like material management on site, the automation and optimisation of
facility management processes and monitoring of operating resources during occupation and
operation of buildings as well as environmentally sound deconstruction planning based on
information gathered with RFID.
2
RFID – Technology
“Radio Frequency Identification” is a technique for the identification of objects with radio
waves. Basically, a RFID system consists of three components: the transponder, the reader,
and antenna.
The transponder contains an integrated circuit (IC, i.e. chip) for the data storage and an
antenna for sending and receiving data. It is directly tagged to the object and also referred to
as “tag”. In general, it is differentiated between two types of transponders. While active
transponders contain a battery for internal power supply, passive transponders gain energy
from the reader’s electromagnetic field [5], [6]. Usually, passive tags are cheaper while active
tags have a higher memory capacity and higher reading ranges. The reader communicates and
reads the information from the tag. Additionally, the reader can send new data to the tag.
These data are usually further transferred to a backend system, like a standardised software
application such as an Enterprise Resource Planning (ERP) system. Attached to the reader is
the antenna. The antenna sends signals of the reader waiting for the reply of the transponder.
For reasons of simplification the device of the reader and antenna will be considered as
“reading device” or “reader”. The reading range of a RFID system depends on the frequency
of the electromagnetic waves. The higher the frequency, the higher the possible reading
ranges. These ranges vary from some millimeters up to several meters. The bandwidth of the
frequencies RFID systems use are subdivided into Low Frequencies (LF), High Frequencies
(HF), Ultra High Frequencies (UHF) and Microwaves. Thereby the frequencies of 135 kHz,
13.56 MHz, 868/915 MHz, 2.45 GHz and 5.8 GHz are most commonly used depending on the
application. 12 Generally, low-frequency tags are used for reading distances less than 25 cm,
for instance, access control or work-in-process inventory. In contrast, high-frequency tags are
used for reading distances of a few meters (smart cards). Ultrahigh-frequency tags are used,
for instance, when high-speed reading is essential and the reading distances account up to
several meters, e.g. for toll payment [2].
RFID has already been proven to be successful for various applications in recent years. A
well-known application is the installation of theft-secure devices, e. g. in supermarkets and
department stores, recognizable by the antennas installed at the cash or exit of the stores.
Therefore, transponders are tagged to the product and activate a signal at the exit of the store
12
A detailed survey of different RFID applications is given by Schoblick [7], Finkenzeller [8], and Schneider [9].
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moving into the reception area of a reading device unless the RFID tag has been deactivated
or removed and kept for further reuse after successful payment for the product. For this
application a simple 1-bit transponder distinguishes between two states which are necessary
for the theft-secure: localization of the tag within or outside reading range.
In contrast to conventional Auto-ID Systems (e.g. Bar Code) RFID bear the following
advantages [10]:
-
Less contact, non line-of-sight identification of objects over long distances,
-
Bulk or mass identification,
-
Insensitivity of the transponders against moisture, dirt and abrasion,
-
Possibility to store larger amounts of data directly at the item, and
-
Possibility to write new data onto the chip of the transponder.
3
Future Prospective on the Application of RFID in Construction
While other industries shift towards the application of RFID to facilitate logistical and
organizational processes, the construction industry is still lagging behind. However, Auto-ID
systems and especially RFID offer enormous potentials for the construction industry during
all phases of the life cycle 13. These potentials are, among others, [11]:
- Improvement of internal and external production as well as logistic processes:
improvement of communication and collaboration while simultaneously decreasing
communication effort, simplified assignment of construction materials, components and
equipment to projects, traceable material flow even during occupation of building, improved
information exchange between suppliers and contractors, direct assignment of products to
projects, information stored on product.
- Increase in construction quality: unique identification and traceability of construction
materials and components, tagging of deconstruction and recovery data to the product or
component.
- Improvement of jobsite security and healthcare: emergency alerts or machines switch offs
in emergency zones, check of completeness of safety working clothing, coupling of operation
permission for machines in dependency on permissions stored on RFID-tags in ID cards for
construction workers.
Hence, RFID can help to increase service and performance levels of the construction industry.
Therefore, different information occurring in the various stages of its life cycle need to be
gathered in order to facilitate optimizing construction processes. Considering a building,
objects for auto identification comprise all project resources except resources like know how
and monetary flows. These resources are:
-
Labour,
-
Material and components, and
-
Equipment.
13
A similar listing then the one introduced in the following can be found, for instance, in [4], [9].
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Technologies for Intelligent Building Services
Thereby, the data occurring over the life cycle of a building (see Fig. 1) for these resources
are for instance:
- Labour: Personal data, such as name, date of birth, information on working status, and
skills.
- Material and components: Master, producer and organizational data, such as the identity of
the material or component in terms of a unique ID, characteristics of material, measures
(master data), name of the manufacturer, date and place of manufacturing (manufacturer
data), or date delivery, maintenance intervals, maintenance, time and type of repair
(organizational data).
- Equipment: Master, producer and organizational data in terms of a unique ID, operation
limitations, name of manufacturer, date of delivery, ownership, or required skills.
Fig. 16. Extended model of the building life cycle [12]
3.1
Production
Similar to other industries like the automotive sector an efficient management of the Supply
Chain (SC) allows enormous potentials in cost reduction, the avoidance of out-of-stock
situations and wrong deliveries as well as the increase in logistical processes. The
construction industry could benefit from improved standardization of incoming goods
inspection as well as the tracking and tracing of construction materials and components [13].
Material Identification. In comparison to barcodes RFID enables the identification of
materials like discrete solids, liquids, gaseous and metals as well as components. For easy
identification, a tag is attached to each of the components. Pallet-level tagging can lead to
even more efficient identification of products and reduce misdirected shipments and enables a
more efficient consignment verification [2], [4], [10], [14]. Fig. 2 illustrates the identification
of building materials supported by a RFID system at the goods receipt on a construction site.
Furthermore, information about building materials, e. g. the name of the supplier, the delivery
date, the amount delivered as well as the way of the delivery, can be stored on the RFID tag
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and enables the supplier as well as the consumer of building materials and components to
trace building materials and components in order to save time collecting necessary
information [15].
Tracking of building materials
with RFID at the entrance of a
construction site
storage
area
storage
area
storage area
Fig. 17. RFID system for the object identification at the goods receipt
For instance, a RFID trial was conducted by Fluor Construction in cooperation with Shaw
industries, a supplier of metal pipes, in September 2003. The aim was to determine whether
RFID could help automate and speed up the identification of building materials. It was shown
that pipes with a length up to 40 feet loaded on a truck could be identified from a distance of
10 feet using a frequency of 915 MHz. In this 100 percent accurate readings had been
recorded [16]. The application of RFID could, hence, reduce lack of information on arrivals of
ordered material and components [10].
Tracking and Tracing of Construction Materials. Despite the control of the delivery
process, warehouse management and stock keeping is eased since a great part of the materials
are usually stored temporarily on the construction site. As site congestion is usually high and
part of the storage space is also assigned randomly RFID could support the identification of
these objects on the building site. Having lost track of certain components and materials RFID
supports the construction worker finding certain building materials and components even over
longer distances without line-of-sight. This could be realized with a simple handheld reader or
via GPS from a certain place onside or outside the construction site, e.g. [17].
3.2
Construction
Access Control. Mainly in office buildings and premises automatic identification and access
control systems have been successfully implemented and since several years. Similar to the
systems used in, for instance, skiing resorts, RFID could be applied at the entrance of a
construction site to automatically activate gate opening mechanism if a person or car moves
into the reception area of the systems reading device after reconciling the personalized data
stored on the transponder. This transponder could be integrated in a plastic card (like access to
parking lots) the construction worker owns and access is granted if the data stored on the card
is verified with the data stored in the backend system.
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Technologies for Intelligent Building Services
Additionally, RFID could be used for the security of construction workers. Evacuating a
construction site with a registration of persons who have already left the emergency area it
would be immediately traceable which worker has already been evacuated. Similar to access
control, the construction worker would carry a card with personal data stored. Onto the
transponders also information about skills, qualifications and authorizations of the
construction worker could be stored. For example, data about skills and permissions for the
use of construction equipment and machines. A RFID reader installed in a construction
machine and vehicle like an excavator, or a crane reconcile the skills of the worker and the
skills which are prerequisite for a utilization of the machine [18]. The engine only starts in
case the reconciliation has been successful.
Anti-Theft Systems and Tool Tracking. As RFID has already been applied in anti-theft
systems for several decades it is also predestined to prevent theft within the construction
industry and on construction sites [18]. Both the loss and thievery of building materials and
equipment is a major problem in the construction industry. US construction industry’s total
costs caused by job-site theft accounted from $300 million to $1 billion in 2004 [20]. For
simple anti-theft applications a 1-bit transponder is sufficient. When a tagged tool is moved
into the reception area of a reading device at the entrance or exit of a construction site, similar
to the application in department stores, alarm is activated. Apart from the application of 1-bit
transponders for tool tracking they could also be used to store additional data like the date and
the place (i.e. construction site A or B) of the last utilization. Using transponders with higher
memory capacity the anti-theft system could also be expanded to an advanced tool tracking
system to serve the following functions [10], [19]:
- Survey of the procurement/leasing and maintenance or modification history of the
equipment,
-
Billing to specific construction projects,
- Information about the utilization of the tool, e.g. of the construction worker who used the
tool, and, as already mentioned,
-
Theft-secure.
Especially information on the maintenance history of the equipment while it is in maintenance
and repair would significantly reduce paperwork occurring for warranties and maintenance
logs [4], [10].
Companies like the Robert Bosch Tool Corp. have begun to sell tools with embedded RFID
tags. Bosch is tagging a total of 66 different tools like circular and reciprocator saws and
hammer drills [20]. Data in these transponders are tool’s model number, order information
and a unique serial number. The system for the tool identification works on a frequency of
915 MHz. The database of a backend-system contains “purchase and service history, billing
rates to specific construction projects, and information on who has used the tool”. The
Electronic Product Code (EPC) on the tag allows “an asset-tracking with a photograph,
specifications, and description of the tool”. 14
14
More information about the tool tracking and theft system are available on Boschtools online [21]. Another
provider of RFID tool tracking solutions is ToolWatch SE [22].
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3.3
Use and Occupation
RFID applications during the use and occupation of a building or constructed object refer to
the automation and optimisation of facility management processes and monitoring of
operating resources during occupation and operation of buildings.
Servicing and Maintenance. During the use and occupation of a building quality
management, maintenance and the restoration operations take place. In these operations the
identification of components and construction materials which have to be replaced, renovated,
or maintained can be supported by RFID.
For example a RFID system has been developed to reduce the maintenance effort of sewer
system (see also [23]). The system works on 13.56 MHz transponders and stores information
about the documented status of maintenance as well as manufacturer’s data. The RFID-tag is
cast into the concrete of the pipes during the fabrication process. The operator of the sewer
system permanently gets information, e.g. of the next necessary maintenance of the pipe or its
manufacturer. The date can be read out by remote-controlled, navigable robots provided with
a RFID reading device attached. The robot placed into the pipe system identifies all
transponders embedded into the concrete by moving through the system. In comparison to a
camera equipped robot or even manual advice, this procedures is less time consuming and
more easy to handle. This is especially relevant as sewer systems last over longer periods of
time. Moreover, a combined identification with camera and RFID could enable engineers to
relate the pipe information to the status quo of the damage and necessary maintenance effort.
Generally, such a maintenance application is also applicable to other products of high value,
for instance, heaters or other electrical or electronic equipment in a building. Read out data,
most likely to be gathered with a Personal Digital Assistant (PDA) are predestined for a
subsequent processing in a backend system.
Operation. In recent years, the “house of future” had been discussed also in terms of RFID
technology which could support the automation of applications within households and during
the utilization of houses. One application of RFID for household is a refrigerator developed
by the German company Liebherr. Liebherr’s refrigerator detects products beyond the date of
expiry and automatically creates a shopping list (see [24]). The information is shown on a
screen integrated into the door. Additionally, the RFID system could inform about products
“out-of-stock” product that have been declared as important by the owner before. As several
companies of the consumer goods industry like Germans Metro AG or the US Company Wal
Mart in association with manufacturers of consumer goods and producers of RFID systems
are planning to tag each single product this vision seems to be quite realistic. Apart from
information about the price and the date of expiry other information stored on the transponder
could be, for instance, ingredients, calories or nutritional values as well as manufacturers and
delivery dates. Another application of RFID is the automated setting of ovens. Therefore, a
RFID antenna is installed in an oven to recognise products with tags. The reading device
initiates related oven settings read out from the cooking instruction at the tag. However, this is
still to be scrutinised in terms of the adoption of food with tags by the consumers. A further
application, although closely related to the manufacturing industry, is the application of RFID
for washing machines. Clothes are signed with tags to either support logistics in the fashion
industry or to monitor working cloth of, for instance, construction workers. Washinginstructions stored on the tag are used to set the optimal washing machine program in order
not to damage cloth. For further information on RFID applications in household appliances
see also [25].
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3.4
Deconstruction
At the end of the life time of a building usually deconstruction takes place. With respect to
environmentally friendly and sound behavior, the aim of deconstruction shall be to allow a
systematic selective deconstruction of buildings which helps to separate different kinds of
building materials and their reutilization in superior utilizations options [26], [27]. Compared
to other industrial products the deconstruction and recovery of buildings or building materials
is quite complex. In several other industries the so called extended producer responsibility
(EPR) with the objective to return spent products or components to their original producers is
already implemented. Apart from components which are routinely replaced or maintained it is
far less likely to return building materials to their manufacturer. The main reason is the
usually long lifetime of a building ranging from 50 to 150 years in comparison to other
industrial products. Before the deconstruction takes place information should be gathered on
the composition of the building, i.e. on materials and components to be deconstructed. This
includes data about the manufacturer, built in date as well as on the contamination with
hazardous substances. According to this information, a deconstruction plan can be set up. This
would also enable a more precise cost estimation of deconstruction projects and prevent
unexpected incidents during the dismantling of the building. However, data about the
composition of buildings might usually be difficult to obtain as, in general, multiple
modifications or renovations during the building’s lifetime take place. If RFID is already used
for renovation processes and new materials or components are tagged with RFID transponders
an identification would become realistic. The data could be read by a reading device (e. g. by
a handheld PDA) from the individual object. If data, e.g. information about the date of
construction, the last date of maintenance, reparations etc., are permanently updated, their
condition is directly available during the deconstruction and recovery planning phase. This is
especially attractive for considerations of reuse of components. Additionally, by the direct
availability of information about the product the data usually cannot get lost during the long
time lag between construction and deconstruction. However, due to technological progress it
still has to be shown whether a technology up to date right now will last a period of 50 to 100
years, i.e. the life time of a building, to be read out.
4
Limitations of RFID in Construction
An empirical investigation including 70 RFID experts has revealed critical success factors for
the implementation of RFID [28]. Around 50 % of the experts mention the interferences
caused by metal or liquids and the missing standardization of frequencies and sending power
present as very high or high limitations to the application of RFID. This is followed by
missing standardization in the area of product identification and reservations against data
protection [4]. Only a small number really think that information security as well as
transponder and reader costs could hamper the application of RFID [28].
Currently, the costs both for RFID reading devices and transponders are quite high because of
their variable character (each object has to be tagged with its own transponder). The prices for
transponders range from $ 20 cents to several dollars for a passive transponders and from 10 $
to 50 $ for active transponders [29]. However, various analysts expect the prices for passive
tags to decrease to 1 - 2 cents during the following years [30]. While the limitations caused by
missing standards (mainly in the area of frequencies and transmitting powers) and data
security can be seen as a challenge in general, and data protection is mainly a topic in the area
of the consumer goods industry, the interferences caused by metal and other environmental
influences like moisture, liquids or dirt are a major concern within the construction industry.
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Especially developed for RFID systems applied in construction RFID manufacturer [31]
developed the so called „((rfid))-onMetal-Label“ and guarantees a reliable identification
without an exertion of the electromagnetic field. The “((rfid))-onMetal-Label” can be tagged
directly to metallic surfaces. The example shows that RFID companies respond to
environmental requirements predominating within certain industries respectively areas of
application. More and more systems and components especially developed to withstand
environmental conditions have been developed recently. The further development of special
components appropriate for the construction industry will be a question of how far there will
be an adoption of RFID within the industry in the future. Here the construction industry could
benefit from the developments within industries with similar conditions like, for instance, the
automotive sector [32].
5
Conclusion and Outlook
In this paper several applications for RFID in construction were highlighted. This ⎯by no
means complete⎯ overview shows that RFID could unveil its benefits even under the harsh
environmental influences in construction. Some of the discussed applications have already
been tested in pilot studies. However, the construction industry is still lagging behind
applying and adapting technologies already successfully implemented in other industrial
sectors. A positive sign towards the application of RFID in construction are the development
of RFID technologies which work under conditions typically for construction, for instance
metal interferences or other environmental influences. This development shows that RFID in
this sector is going to be an increasingly important topic both from an economically as well as
scientific point of view.
References
1. RFID central: http://www.rfidc.com/docs/introductiontorfid_business.htm (2007)
2. Srivastava, B.: Radio frequency ID technology: The next revolution in SCM. Business
Horizons, 47, 6 (2004) 60-68
3. Wing, R.: RFID applications in construction and Facilities Management, ITcon Vol. 11,
Special Issue IT in Facility Management, http://www.itcon.org/2006/50, 11 (2006) 711721
4. Jaselskis, E., El-Misalami, T.: Implementing Radio Frequency Identification in the
Construction Process. Journal of Construction Engineering and Management, 129, 6
(2003) 680-688
5. Sweeney, P.: RFID for Dummies – Get up to speed on Radio Frequency Identification.
Indianapolis: Wiley Publishing (2005)
6. Jilovec, N.: EDI, UCCnet & RFID – Synchronizing the Supply Chain. 29th Street Press.
Loveland, Colorado (2004)
7. Schoblick, R., Schoblick, G.: RFID – Radio Frequency Identification. Poing: Franzis
(2005)
8. Finkenzeller, K.: RFID Handbook – Fundamentals and Applications in Contactless Smart
Cards and Identification. Wiley, England (2003)
9. Schneider, M.: Radio Frequency Identification (RFID) Technology and its Applications in
the Commercial Construction Industry. Proceedings of the International Conference on
Computing in Civil and Building Engineering - ICCCBE, 10, 2004.06.02 – 04, Weimar
(2004)
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10. Jaselskis, E., Anderson, M.R., Jahren, C.T., Rodriguez, Y., Njos, S.: Radio-Frequency
Identification Applications in Construction Industry. Journal of Construction Engineering
and Management, 121, 2 (1995) 189-196
11. RFID im Bau: http://www.rfidimbau.de/pages/rfid-inwemo/forschungsziel.php (2007)
12. Lützkendorf, T.; Lorenz, D.P.: Using an integrated performance approach in building
assessment tools. Building Research & Information, 34,4 (2006) 334-356.
13. Simchi-Levi, D., Kaminsky, P. and Simchi-Levi, E.: Managing the Supply Chain – The
Definitive Guide for the Business Professional. McGraw-Hill, New York (2004)
14. Yagi, J., Arai, E. and Arai, T.: Parts and packets unification radio frequency identification
application for construction. Automation in Construction, 14, 4 (2005) 477-490
15. Matsuda, T., Yashiro, T., Nishimoto, K., Shida, H., Shiono, Y. and Aikawa, N.: Resource
value enhancement and downstream logistics management by improved traceability using
RFID-Tag. Proceedings of the 2005 World Sustainable Building Conference in Tokyo
SB05 (2005) 1276-1281
16. Collins, J.: Case Builds for RFID in Construction. RFID Journal.
http://www.identecsolutions.com/pdf/IDENTECSOLUTIONS_RFIDConstruction _RFID
%20Journal.pdf (2005/07/08) (2004)
17. Song, J., Haas, C.T., Calda, C.H.: Tracking the Location of Materials on Construction Job
Sites. Journal of Construction Engineering and Management, 132, 9 (2006) 911-918
18. Littlefield, D.: Electronic tagging could transform site practice. Building Design, October,
24 (2003)
19. Goodrum, P.M., McLaren, M.A., Durfee, A.: The application of active radio frequency
identification technology for tool tracking on construction job sites. Automation in
Construction, 15, 3 (2006) 292-302
20. Informationweek: RFID Helps Stop Power Tools ‘Walking Off’ Job Sites.
http://www.informationweek.com/story/showArticle.jhtml?articleID=164302475
(18.07.2005) (2005).
21. Bosch:
SAFE
&
SOUND™
RFID
Tool
Tracking
&
Service.
http://www.boschtools.com/about-bosch-tools/press-room/2005-archives/SafeSoundRFIDToolTracking.htm (2007/11/16) (2005)
22. Toolwatch: http://www.toolwatch.com (2007)
23. IDENT: Neue RFID-Lösung in der Bauindustrie – Wartungsoptimierung durch
„intelligente“ Betonrohre. 3 (2005), 17 (in German)
24. Metro: http://www.futurestore. org/servlet/PB/-s/1lk7yinnwq2891 kbj00erdncoyv3vrt1/
menu/1003293_l2/1120219011633.html (2005/08/02) (2005)
25. RFID Journal: Merloni unveils RFID appliances. http://www.rfidjournal.com/
article/articleview/369/1/1/ (2005/07/31). (2003)
26. Schultmann, F., Rentz, O.: Scheduling of deconstruction projects under resource
constraints. Construction Management and Economics, 20 (2002) 391-401
27. Schultmann, F.: Sustainable deconstruction of buildings. In: Yang, J., Brandon, P.S.,
Sidwell, A.C. (eds): Smart and Sustainable Built Environments. Blackwell Publishing
(2005) 148-159
28. (BSI) Bundesamt für Sicherheit in der Informationstechnik (2004): Risiken und Chancen
des Einsatzes von RFID-Systemen. SecuMedia. Ingelheim und Bonn 2004.
29. RFID Journal: RFID System Components and Costs. RFID Journal.
http://www.rfidjournal.com/article/articleview/1336/1/129/ (2005/08/08) (2005)
30. Collins, J.: Estimating RFID’s Pace of Adoption. RFID Journal.
Requested online on http://www.rfidjournal.com/article/articleview/675/1/1/
(2005/08/02) (2003)
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31. Schreiner Logidata: ((rfid))-onMetal-Label. http://www.schreinergroup.de/
wEnglisch/schreiner_logidata/Produkte/RFID_Loesungen/RFID_onMetalLabel.shtml
(2005/06/30) (2005)
32. Collins, J.: Avery Designs Passive UHF Tag for Metal. RFID Journal.
http://www.rfidjournal.com/article/articleview/1436/1/10/ (2005/08/15) (2005)
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Construction Processes for the Digital ‘Trinity’
Rupert Soar2 and Farid Fouchal1,
1 Department of Civil and Building Engineering, Loughborough University, Loughborough,
Leicestershire, LE11 3TU, United Kingdom
2 Wolfson School of Mechanical and Manufacturing Engineering, Loughborough University, Loughborough,
Leicestershire, LE11 3TU, United Kingdom
{[email protected], [email protected]}
Abstract
In this paper a review of some digital manufacturing technologies applied to construction is given. At the core of these
technologies lies the belief that processes may be numerically controlled to make things directly, which is clearly
distinguished from the currently existing indirect digital methods to produce objects. Three system under development in the
construction sector are described, these are: the Threshold Deposition Device, the Monolite Process and the Contour
Crafting. Furthermore, the Freeform Construction (FC) was introduced with its aim, which is offering a solution for
fabrication of optimised structures for construction. An important change is about to happen to the way we make our
habitats, this is introduced as the Biomimetic principle for future human homes. The organic system are highly optimised
and are capable to induce environmental control only by evolving construction methods which utilise geometric form.
Inspiration from these systems together with the Freeform Construction technology the new generation of homes is becoming
reality.
Keywords
Additive Manufacturing, Freeform Construction, Rapid Manufacturing, Biomimetics systems.
1
Introduction
Additive Manufacturing Technologies (AMTs) for Construction, known as “ Freeform
Construction “ represent new construction methods based firmly within a broader digital
context of digital design. The roots of Freeform Construction lie in a class of
manufacturing processes loosely termed additive, layer, freeform or rapid manufacturing,
which over the last 15 years have seen steady growth and uptake within predominantly the
automotive, aerospace and consumer goods sector. These processes, however, may be
further linked to later manufacturing systems on a smaller scale from the nano-scale upwards
with, for example silicon wafer manufacturing and MEMS technologies. Though an
exciting concept for the non-construction sector, the idea of fabricating components from
layers, lies at the very heart of construction practice. In fact fabricating components in
layers is where much of the excitement lies in the manufacturing sector as it allows them to
move away from conventional mould making and machining from large blocks of material.
Mass customisation is what construction does, so what can construction learn from these new
emerging machines in the manufacturing centre?
2
Direct Digital Manufacturing in Construction
Rapid manufacturing is about digital manufacture. At its core lies the belief that processes
may be numerically controlled to make things ‘directly’. ‘Directly’ means the same as
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pressing ‘print’ on a P.C. Digital data is passed to the printer where is it fabricated as ink on
paper and rapid manufacturing is the 3D version of this process. This must not be mistaken
for ‘indirect’ digital processes. As the name implies, fabricating digitally designed
components may be performed indirectly, i.e. digital data is sent to a machine which makes a
mould, into which materials is cast, or data is sent to sets of machines which make sub
assemblies which are then assembled into a finished component. Offsite fabrication
processes are an example of this approach. The adoption of manufacturing automation
principles and equipment is set ‘off-site’ in the controllable environment of a factory. This
is not to say ‘off-site’ practice falls short for construction. Indirect and offsite methods for
construction are the only way, currently, of realising highly complex geometry and structure
and we are seeing remarkable examples of this work.
Digitally driven ‘direct’ fabrication methods [we use the term freeform construction as an
alternative to traditional ‘wet construction’ practice and modern ‘dry construction’ practice.
We are also implying that FC may be both digitally driven wet and dry systems, performed
either on or off-site, with the emphasis on direct fabrication] represent an approach which
ties in intimately with the changes undergoing architecture, structural and utilities
engineering. Digital systems require the pulling down of existing division of labour within
construction practice. ‘Lean’ practice demands concurrency or the grouping of all
construction activities from concept to product. In fact the analogy for this change is in
everyone’s desktop or table.
The computer now sits at the heart of our lives, but it is not simply the processor. The
entire P.C. package typically includes a keyboard and mouse (maybe a scanner), then a
processor and finally a printer. Essentially, these can be reduced to input devices,
manipulation devices and output devices. The interesting thing is that whether relating this
to your desktop P.C. or a complete digital manufacturing system, the analogy shown in figure
1, is scalable.
2. Manipulate/Analyse
Simulation
FEA/CFD
Optimisation
Adding Functionality
3. Output/Print
Offsite/Onsite
Heterogeneous or
continuous
1. Input/Capture
Scanning
Parametric CAD
Recapture in process
Fig. 9 Diagram showing how input, manipulation and output devices link together.
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If we apply the analogy back to digital construction, then the inputs expand to encompass
scanning, digitising, CAD/CAM inputs, BIM inputs. All data must be manipulated, and with
this we introduce simulations, algorithms, optimisation etc. Freeform construction is
therefore the digital output to this procedure and implies one further component. The
‘trinity’ model is cyclical, i.e. outputs intrinsically feed back into inputs. To give an
example of this, those freeform construction processes in development have the ability to take
digital data directly from a 3D model. Through varying methods which control the
deposition process and phase change strategy of the material the device replicates the 3D
geometry. What if an error occurs and detail is missed, or a small detail collapses during the
build? In an automated system, how will the machine know that an error has occurred?
Herein lies the reason for the closed loop. As the deposition of each layer occurs a camera
re-scans each deposited layer and sequentially re-builds a digital model of the ‘real’ or printed
structure. The ‘real’ model is then cross referenced to the digital model and any drift from
tolerance is highlighted and either an adjustment made or an alarm allows the error to be
corrected by the operator.
This is just one of the challenges facing FC technologies.
The first to conceptualise freeform construction was Joseph Pegna, 1997 [1]. He classified
rapid manufacturing solutions (available then), in terms of material delivery and deposition
rates. His calculations revealed that volumetric flow rate of 1.04 m3 h -1 is required for a an
average two-story house (see table 1). As a result he embarked in an experimental work to
demonstrate a solution that was both neat and innovative and he proceeded, to design, test and
validate a blanket sand deposition process followed by selective deposition of Portland
cement through a mask, using water as the binding agent. The application of water to sand
and cement does not produce a robust structure, so Pegna developed a pressurised steaming
process which proved sufficient to generate structurally robust parts for testing, the eventual
process steps are as shown in figure 2.
1
2
Blanket Diposition
of Matrix Material
3
Selective Deposition of
Reactive Agent
Activation of
Reactive Agent
(a)
1
2
Blanket Diposition
of Matrix Material
3
Masking of Matrix
Material
4
Blanket Diposition of
Reactive Bulk Material
Removal of Mast
and Excess
Material
5
Activation of
Reative Material
(b)
Fig. 2 Process steps of selective deposition process of SFC, (a) actual automated fabrication process, (b)
manually implemented fabrication process. (after Pegna)
Building
Height
7.5m
Building
base area
200m2
Required
Number of
volumetric
floors
rate
2
flow
1.04m3 per hour
Estimated
construction time
1440 hours
Table 2 Parameters used by Joseph Pegna to calculate the flow rate required to build an average two-story
house
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Currently there are three systems under development or close to commercialisation in the
UK, Italy and the USA. Each uses a different strategy to form full-scale structures. In the
UK, the Threshold Deposition Device (TDD), describes the way in which extruded paste
rheology is exploited for shear thinning and shear thickening behaviour. The first iteration
of this method is designed to use ‘off-the-shelf’ components with the intention that it may be
reproduced easily. The controls, drivers, the gantry, the pumps and even the material are all
commercial products. The machine works to a 1mm tolerance and has positional accuracy
down to 0.1mm, with a build envelope of 6x5x4 metres.
In Pisa, Italy, Enrico Dini is commercialising the Monolite process (see figure 3). The
process deposits layers of particulate, ranging from sand to marble chips, onto which the
deposition head selective jets a binder which may be cementitious or polymeric. This
solution overcomes the problems of supports by printing into a powder bed, after which the
part is extricated, see figure 4.
Fig. 3 Monolite process [by Enrico Dini, Pisa, Italy]
Fig. 4 Monolite and Gazeebo as built by Enrico Dini, Italy]
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The final process, in this category is by Behrokh Khoshnevis at the University of Southern
California in the USA. Termed contour crafting, the process seeks a solution to selectively
deposit material at ‘bulk rate’ whilst manipulating the deposited material with a trowel as
shown in figure 5. Surface finishes are as good as a plasterer can achieve.
Fig. 5 Prototype wall by CC, (a) Full scale concrete straight wall section, (b) filler/core material within a surface
skin structure (Khoshnevis, 2005).
The process is one of layer by layer extrusion for fabricating structures at a range of scales,
simultaneously on the construction site. Some of the important features of CC are high
fabrication rates and the ability to use a wider choice of build materials (Khoshnevis, 2004)
[2].
Using thixotropic materials with rapid curing properties and low shrinkage
characteristics, consecutive layers of wall structures can be built, by an incremental controlled
of thickness as can be seen in Figure 6.
Fig. 6 CC extrusion process, (a) extrusion nozzle with active side trowel, (b) extrusion nozzle with integrated
trowel (Khoshnevis, 2004).
In CC, the deposition of build materials is carried out in two stages. In order to improve
the finish of the visible surfaces, extruded materials at the shutter of the nozzle is shaped and
smoothed by a secondary manipulator (trowel), as it is extruded. CC is a hybrid method,
where the extrusion process for forming object surfaces and filling the object core are
combined. CC has successfully demonstrated the fabrication of a prototype full scale
straight wall, using concrete material, as shown in figure 6 (Khoshnevis, 2005) [3].
Worth mentioning also is the DFAB ARCH project in Zurich. Taking the digital concept
literally, the group have produced remarkable work by automating the placement and bonding
of bricks. The project should not be looked upon purely as a nice thing to do with bricks, it
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goes much further than this. The research takes the basic unit of the brick and manipulates it
as a component of a larger, functional, set of bricks. On its own, a brick is a brick, but by
selective placement a structure is generated with functions exceeding that of a wall. Walls
become membranes, capable of interacting with wind and insolation effects to control internal
environments.
The challenge of FC is to produce all the detail on a single slice. For example, the
deposition of 10 mm beads of material will not make it possible to define internal channels at
20 mm diameter. Any process developed for FC must be able to deposit materials both at
construction rates and with the resolution of the smallest element which must be defined
within that structure. The challenge is therefore to attain rapid deposition rates, whilst
maintaining resolution of the smallest feature. In figure 7 one can see the expected decrease
in resolution with increasing deposition rates ranging form AMTs to conventional
construction methods.
Freeform construction processes enable a structure to be optimised, in terms of its
functional requirements, through the selective deposition and grading of different materials.
Structural load dissipation is probably the most obvious application, with strengthening
materials being deposited simultaneously with a more general construction material as defined
and derived from both FEA and CFD analysis of the 3D CAD form.
Fig. 7 Shows the expected decrease in resolution with increasing deposition rates for processes ranging from
micro RM to existing construction methods.
Structural optimisation of a system, containing multiple constraints/variables, assumes no
single solution which satisfies all conditions. Which solution dominates depends on the state
of the system at that point in time. AMT’s potentially offer the first approach by which
optimised structures can be derived, within a CAD system, and be reproduced into a physical
structure or component of a minimal number of combined materials. Figure 8, shows where
a typical cross-section of a pre-assembled external wall, including fixtures and fittings, may
contain around fifteen different materials. Each of these materials generates waste which is
both mixed in the factory, prior to assembly on-site, or upon demolition.
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Integrated channelling
& ducting for services
and HVAC
Internal cellular geometry
optimised for thermal,
acoustic & moisture
permeability
External texturing
for enhanced
surface area and
perceived ‘quality’
Fig. 8 Typical cross-section through an external wall element and Impression of the capabilities for a single
material external wall section. (courtesy of Rupert Soar)
3
Beyond Biomimetics for Human Habitats
Organic systems optimise dynamically, they have the ability to physically change their
form, to remain at an optimum, within a changing environment on a daily basis. Trees,
plants and corral, like current AMT processes, are additive processes but, unlike AMT’s, trees
continue to find optimum solutions on a daily basis through growth. The physical structures
built by social insects, go one stage further by incorporating both additive and subtractive
capabilities within their optimisation process. It has long been known that some ant and
termite structures possess, adaptive capabilities which result in high levels of self-regulation
of the internal environment of the habitats they build (known as homeostasis).
Some of the higher orders of termites (Macrotermitine) [4-6] have gone an extra stage by
evolving construction methods which utilise geometric form to induce environmental control.
Some of these mounds utilise a central open chimney, sometimes rising many metres into the
air. In the same way our own chimneys work. Buoyancy driven respiratory gasses are drawn
up through the mound, which replenishes respiratory gasses. There is, however, one
particular family of termites who have evolved a construction method known as the
‘cathedral’ or closed structure. These tall closed structures, shown in Figure 9 a-c, attain
high levels of environmental control without recourse to an open topped chimney.
These
structures are found throughout sub-Saharan Africa and are able to regulate internal
environmental conditions by inducing or retarding energy flows both in to and out of the
structure and probably represent the ultimate in ‘smart’ construction.
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Technologies for Intelligent Building Services
lateral
connectives
central
chimney
mound
surface
conduit
radial
channel
fungus
gardens
galleries
cellar
(a)
Fig. 9
(b)
(c)
Macrotermes michaelseni mound with schematic and exposed underlying vascular system.
Figure 9c shows the internal voids and channels, inside a mound, which was filled with
plaster, then the mound material washed away to reveal the underlying structure. These
mounds have formed the study for novel passive ventilation mechanisms whereby the
physical structure interacts with energy flows in the environment (wind and insolation) and
the natural convection states found within the mound. Essentially the mounds are
‘massively passive’ in that they achieve complete regulation and control for the colony to
thrive. They are neither retrofitted with ‘green’ technologies or require electricity to power
the system.
As part of the workshop activities for this conference we will be revealing our
discoveries on how this system works and its implications for sustainable construction
practice.
4
Conclusion
Construction is an additive process, the current state-of-the-art in this sector focuses on
modular solutions, either fabricated directly on-site or as pre-assembly solutions prepared offsite. Freeform construction is the way forward for automation of the additive aspect by
digitally incorporating material preparation, delivery, and deposition into a single operation.
Rapid manufacturing technologies have matured enough to forge a route into sustainable
construction practice by strategically moving to mineral systems derived within the locale of
the construction process.
Freeform construction offers increased functionality as one of the
strongest points this technology has to offer as a clear link between computational based
structural optimisation and the physical object fabrication. The potential for ‘single
material’ structures, integrated services, self-supporting geometries, structural homoeostasis,
waste reduction and complete building recycling offer a ‘step changes’ to the construction
process which many are currently seeking answers for.
References
1. Pegna, J., (1997), "Exploratory investigation of solid freeform construction", Automation
in Construction, vol. 5, no. 5, pp. 427-437.
2. Khoshnevis, B., (2004), Automated Construction by Contour Crafting – Related Robotics
and Information Technologies, pub in Journal of Automation in Construction – Special
Issue: The best of ISARC 2002, Vol 13, Issue 1, January 2004, pp 5-19.
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3. Khoshnevis, B., Russell, R., Kwon, H. & Bukkapatnam, S., (2001b) Contour Crafting – A
Layered Fabrication Technique, Special Issue of IEEE Robotics and Automation
Magazine, 8:3 (2001-a) 33-42.
4. Turner, J. S. 2000, Architecture and morphogenesis in the mound of Macrotermes
michaelseni (Sjostedt) (Isoptera: Termitidae, Macrotermitinae) in northern Namibia.
Cimbebasia 16: 143–175.
5. Turner, J. S. 2000, The extended organism. The physiology of animal-built structures.
Harvard University Press, Cambridge, MA.
6. Turner, J. S. 2001, On the mound of Macrotermes michaelseni as an organ of respiratory
gas exchange. Physiol. Biochem. Zool. 74: 798–822.
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Beyond Biomimicry: What Termites Can Tell Us about Realizing
the Living Building.
J Scott Turner1 and Rupert C Soar2
1
SUNY College of Environmental Science & Forestry, Syracuse, New York, USA
2
Wolfson School of Mechanical and Manufacturing Engineering,
Loughborough University, Leicester, UK
Abstract
Termites and the structures they build have been used as exemplars of biomimetic designs for climate control in
buildings, like Zimbabwe’s Eastgate Centre, and various other “termite-inspired” buildings. Remarkably, these
designs are based upon an erroneous conception of how termite mounds actually work. In this article, we review
recent progress in the structure and function of termite mounds, and outline new biomimetic building designs that
could arise from this better understanding. We also suggest that the termite “extended organism” provides a model to
take architecture “beyond biomimicry”—from buildings that merely imitate life to buildings that are, in a sense, alive.
Keywords
biomimicry, termite, Eastgate Centre, Macrotermes, termite mound, gas exchange, temperature
regulation, homeostasis, rapid manufacturing, free-form construction, extended organism
1
The Eastgate Centre. A biomimicry watershed
Harare’s Eastgate Centre, which opened in 1996, deservedly stands as an iconic biomimetic
building (Figure 1). Mick Pearce, the project’s lead architect, wanted the building to reflect
two tenets of his philosophy of “tropical architecture”—first, that design principles developed
in the temperate northern hemisphere are ill-suited to tropical climes like Zimbabwe’s; and
second, that effective design should draw inspiration from local nature [1].
Where Pearce drew his inspiration was from the remarkable mound-building termites of
southern Africa (Figure 1). These creatures are themselves architects of sorts, building
massive mounds that in some instances tower several meters high. The mound serves as
climate-control infrastructure for the termite colony’s subterranean nest. Pearce reasoned that
the architectural principles of the termite mound, honed to sleek efficiency by the relentless
refining of natural selection, could inspire buildings that perform equally well. By all
measures, his vision succeeded brilliantly.
For the past several years, we have been studying the structure and function of the termite
mounds that inspired Mick Pearce. In the process, we have learned many things, among them
something quite remarkable: the Eastgate Centre is modeled on an erroneous conception of
how termite mounds actually work. This is not intended to be a criticism, of course: Pearce
was only following the prevailing ideas of the day, and the end result was a successful
building anyway. But termite mounds turn out to be much more interesting in their function
than had previously been imagined. We believe this betokens expansive possibilities for new
“termite-inspired” building designs that go beyond Pearce’s original vision: buildings that are
not simply inspired by life—biomimetic buildings—but that are, in a sense, as alive as their
inhabitants and the living nature in which they are embedded.
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Fig. 1. The Eastgate Centre and a Macrotermes mound. a-b. The exterior of the Eastgate Centre, showing
chimneys along the roof 15. c. The interior atrium of the Eastgate Centre 16. d. A mound of Macrotermes
michaelseni in northern Namibia.
2
How the Eastgate Centre is like a termite mound
If Eastgate was inspired by termite mounds, what precisely about them was the inspiration?
This is not as simple a question as it might seem. Termite mounds are structurally diverse—
some are festooned with one or more large vents, others have no obvious openings to the
outside, and shapes range from cones to pillars to hemispheres [2-6]. Most biologists believe
this structural diversity betokens a diversity of function [7]. As we shall show, this turns out
mostly to be incorrect. What makes Eastgate all the more remarkable is that it melds many of
these diverse, and in some instances contradictory, design features into a single functional
building.
The earliest model for termite mound function was Martin Lüscher’s thermosiphon
mechanism, in which the mound is a venue for metabolism-driven circulation of air [8]. Here,
the colony’s production of heat (roughly 100 watts) imparts sufficient buoyancy to the nest air
to loft it up into the mound and to drive it eventually to the mound’s porous surface. There,
the spent air is refreshed as heat, water vapor and respiratory gases exchange with the
atmosphere across the porous walls. The higher density of the refreshed air then forces it
downward into open spaces below the nest and eventually through the nest again. This
mechanism was thought to operate in mounds with capped chimneys, those that have no
obvious vents.
15
www.archpaper.com/features/2007_14_imitation.htm
16http://blog.miragestudio7.com/wpcontent/uploads2/2007/12/eastgate_centre_harare_zimbabwe_interior_mick_pearce.jpg
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Fig. 2. Two early models for mound ventilation. Left. Thermosiphon flow thought to occur in capped
chimney mounds. Right. Induced flow thought to occur in open-chimney mounds.
The second model is known to biologists as induced flow [9-11], but it is probably better
known to architects and engineers as the stack effect. This mechanism was thought to occur in
open-chimney mounds [12]. Because the mound extends upward through the surface
boundary layer, the large chimney vent is exposed to higher wind velocities than are openings
closer to the ground. A Venturi flow then draws fresh air into the mound through the groundlevel openings, then through the nest and finally out through the chimney. Unlike the
thermosiphon model’s circulatory flow, induced flow is unidirectional.
The similarities between the Eastgate Centre and termite mounds now become clear. The
induced flow principle is evident in the row of tall stacks that open into voluminous air spaces
that permeate through the building (Figure 1). Meanwhile, heat from the building’s occupants
and machinery, along with stored heat in the building’s thermal mass, helps drive a
thermosiphon flow from offices and shops upward toward the rooftop stacks. In the climate of
Harare, the combination provides for an impressive steadiness of interior temperature,
accomplished without resorting to a costly and energy-hungry air-conditioning plant. This is
where most of the building’s efficiencies accrue.
3
How the Eastgate Centre is not like a termite mound
The design and function of the Eastgate Centre departs from termite mounds in some
significant respects, however, and this makes for some interesting design anomalies.
One of the more interesting involves temperature regulation. In the architectural literature,
discussions of the Eastgate Centre are often accompanied by encomia to the impressive
thermoregulatory abilities of the mound building termites. A few quotes make the point:
“The Eastgate building is modeled on the self-cooling mounds of Macrotermes
michaelseni, termites that maintain the temperature inside their nest to within one
degree of 31 °C, day and night … “ 17
17
http://www.biomimicryinstitute.org/case-studies/case-studies/termite-inspired-air-conditioning.html
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“Indeed, termites must live in a constant temperature of exactly 87 degrees (F) to
survive.” 18
“Termites farm fungus deep inside their mounds. To do so, the internal temperature
must remain at a steady 87 degrees F.” 19
“The fungus must be kept at exactly 87 degrees … “ 20
There is just one problem: there is no evidence that termites regulate nest temperature.
Indeed, there is good evidence that they do not. In the subterranean nest of Macrotermes
michaelseni, for example, while temperatures are strongly damped through the day, they also
closely track deep soil temperatures through the year (Figure 3). Consequently, the annual
march of temperature in the nest ranges from about 14oC in winter to more than 31oC in the
summer, a span of nearly 17oC. Nor is there any evidence that mound ventilation affects nest
temperature. In the nest of Odontotermes transvaalensis, which builds open-chimney mounds,
Fig. 3. The annual march of temperature in the nest of a Macrotermes michaelseni colony in northern
Namibia. For comparison, ground temperature 15 m away and at 1 m depth is also plotted.
eliminating ventilation altogether (by capping the open chimney) produces no discernible
effect on nest temperature [13]. These observations have a straightforward explanation: nests
are embedded in the capacious thermal sink of the deep soil, and the nest energy balance (and
hence its temperature) is strongly driven by this large thermal capacity. This produces the
nest’s strongly damped temperatures, but the mound infrastructure and nest ventilation has
virtually nothing to do with it.
This points to one of Eastgate’s interesting design anomalies. Like termite mounds,
Eastgate uses thermal capacity to damp temperature excursions through the day. Over the
long term, however, damping is less effective, as is demonstrably the case in termite nests
(Figure 3). To counter this, Eastgate makes clever use of a daily fan-driven ventilation cycle:
low-capacity fans operate during the day, while high capacity fans operate at night. During
18 http://www.aia.org/aiarchitect/thisweek03/tw0131/0131tw5bestpract_termite.htm
19 http://database.biomimicry.org/item.php?table=product&id=1007
20 http://www.zpluspartners.com/zblog/archive/2004_01_24_zblogarchive.html
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Harare’s typically warm days, the low volume turnover of air in the building facilitates heat
storage in the building’s fabric, keeping internal temperatures cool. During the typically cool
nights, the high volume fans are deployed to extract stored heat from the building’s highthermal-capacity walls, essentially “emptying” them to receive a new load of heat the next
day. Thus, even though Eastgate can dispense with an air conditioning plant, it still requires a
forced-air plant to drive the required daily ventilation cycle. No termite colony does this.
Interaction with wind presents another interesting divergence between termite mounds and
buildings like Eastgate. Wind has practical value as an energy source if it is predictable and
reliable. Yet wind, by its very nature, is variable and unpredictable [14]. A building design
that seeks to harness wind must therefore seek those aspects of the wind resource that
maximize reliability. This is why it is common for buildings that tap wind energy to be
designed around some variation on the induced flow principle: one of the most predictable
features of natural winds is the vertical gradient in wind speed (and hence wind-borne kinetic
energy) that comprises the surface boundary layer.
Termite mounds also exploit boundary layer winds, of course, but with some important
differences. Natural winds are unreliable in large part because natural winds are nearly always
turbulent winds. At a particular location, this means there is a high probability that the wind
velocity vector will vary significantly over time, in both the speed and direction components
of the vector. Thus, any scheme that aims to capture wind at a particular location will be
inherently unreliable. Induced flow works because it has a reliability advantage: the likelihood
of a boundary layer gradient between two locations is very high compared to the likelihood of
a particular wind velocity at one location. This reliability advantage is increased by height
difference between the wind capture points, so for a building to be reliably ventilated by
induced flow, it must therefore be tall. Termite mounds, in contrast, are comparatively short,
usually only a meter or two in height, and this reduces the reliability advantage
commensurably. As a result, induced flow rarely operates in termite mounds, even in openchimney mounds where the structure would seem to strongly favor it [13, 15, 16].
Finally, there is the assumption that mound ventilation also means nest ventilation. This has
long been the prevailing assumption in termite biology (and in building designs inspired by
termites). Surprisingly, there is no evidence that supports this claim, whether ventilation is
driven by wind (induced flow) or heat (thermosiphon flow). Indeed, measurements of actual
flows of air in termite nests and mounds (using tracer gases) indicate that air in the mound is
almost never driven into the nest [15]. This signifies, among other things, that other
mechanisms beside ventilation must be involved in mediating the mound’s function,
respiratory gas exchange.
Termite-inspired building designs thus depart in some significant ways from the
conventional view of how termite mounds work. How, then, do termite mounds actually
work?
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4
How a termite mound is like a lung
The termite mound is but one part of a larger integrated system that includes the
subterranean nest and the complex reticulum of termite-excavated tunnels (Figure 4) that
permeate the mound. These both extend upward into the mound and downward to envelop the
nest (Figure 4).7 This system is the functional analogue of a lung, and like the lung, multiple
layers of subsidiary function are involved in the global function of colony gas exchange.
Previous models for mound function have fallen short because they have not accounted for
these functional complexities.
Fig. 4. The internal structure of a Macrotermes michaelseni mound. a. Plaster cast of a portion of the
superficial tunnel network showing egress tunnels and surface conduits. The mound surface has been
partially washed away. b. Plaster cast of the deep tunnel reticulum in a mound of Macrotermes michaelseni.
c. Plaster cast of the subterranean reticulum that envelops the nest. The nest is just visible behind the
reticulum. d. A horizontal slice at roughly 1 m above ground level through a plaster filled mound. The
reticulum and surface conduits are indicated. e. Cross section through the subterranean nest, showing the
galleries (the fungus combs are the yellowish masses inside the galleries) and the base of the chimney
opening into the nest.
Commonly, physiologists describe the lung as a multi-phase gas exchanger (Figure 5, [17,
18]). Ventilation is only one phase, and it operates in the lung’s upper airways (the trachea
and several branches of the bronchial tree). There, gas exchange is dominated strongly by
forced convection driven by the respiratory muscles. In the lung’s terminal passages—the
alveoli and alveolar ducts—gas exchange is dominated by diffusion, and there is virtually no
bulk flow of air there. Sandwiched between these phases is an extensive region of the lung,
which includes the fine bronchi and bronchioles, where neither forced convection nor
diffusion dominates flux. This mixed-regime region is the site of the overall control of lung
function. This is dramatically evident in asthma, which is a constriction disorder of the mixedregime airways. Small constrictions of these airways during an asthma attack
disproportionately compromises lung gas exchange in a way that similar constriction of the
upper airways do not.
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Fig. 5. Functional organization of the lung
Fig. 6. Functional organization of a termite mound.
This casts lung ventilation into a somewhat different perspective from how we normally
view it. For example, when respiratory exchange is elevated, as it might be during exercise,
increased ventilation (heavier breathing) does not itself enhance respiratory flux, as most
might think. Rather, increased ventilation works its effect secondarily by enhancing gas
exchange through the limiting mixed-regime phase.
Termite colonies have a similar functional organization (Figure 6). As in lungs, there is an
ultimate diffusion phase, which is located within the termites themselves: indeed, one can
think of the termites as mobile alveoli. The termites, in turn, are embedded within the nest,
which comprises numerous galleries separated by thin walls that are perforated by a few large
pores (2-3 mm diameter). The nest, meanwhile, is embedded in the larger reticulum of largediameter tunnels that permeate the mound. The nest galleries connect to the reticulum above
the nest via a capacious space, the chimney. The reticulum of subterranean tunnels that
envelops the nest appears to connect to the nest at its base. Air movements in the nest and
subterranean reticulum appear to be dominated by natural convection, powered by the
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substantial metabolism that is concentrated within the nest.21 Finally, the reticulum extends to
the mound surface to encompass a web of vertically-biased surface conduits: these ultimately
open to many small egress tunnels that project to the surface and serve as zones of mound
porosity. In the surface conduits and egress tunnels, air movements are strongly driven by
wind. As it is in lungs, the colony’s respiratory function is dominated by a mixed-phase
regime that is sandwiched between the subterranean structures (where natural convection
dominates), and the upper parts and peripheral air spaces of the mound (where wind-driven
forced convection dominates). By our best estimates, this mixed natural/forced convection
regime occupies the lower parts of the chimney and the deeper parts of the mound reticulum
[15].
The mound is the principal interface of this complex with environmental winds. Most
thinking about termite mounds (or termite-inspired buildings) has idealized this as a flowthrough system driven by idealized gradients in wind energy. It is common, for example, to
see diagrams of mounds (or buildings) with winds depicted as a vector with implicitly
predictable and well-behaved velocity and direction. To render a useful analogy, there is a
tendency to idealize wind as a DC energy source, and to characterize the mound (or building)
as essentially a resistance load that spans a DC gradient in potential energy (such as the
surface boundary layer). Function is then defined by the DC work done, that is, bulk
movement of air through the building’s occupied space, as in induced flow.
However, neither lungs nor termite mounds are DC systems and it is inapt to treat them that
way. Rather, they are more properly thought of as AC systems, driven by dynamic transients
in the energy that powers their function [19]. Lung ventilation, for example, is driven by an
AC “motor”, namely the tidal movement of air driven by the cyclically active respiratory
muscles. What determines lung function is the depth to which this AC energy can penetrate
and influence exchange across the mixed-regime phase. Similarly, termite mounds capture
energy in the chaotic transients that are the defining features of “badly-behaved” turbulent
winds. The mound’s function, however, depends upon how deeply this AC energy can
penetrate into and do work in the mound. In both instances, function is essentially AC work,
driven by the capture of AC energy across an impedance, not a resistance.
Many peculiar aspects of lung (and mound) function can only be understood in this context.
One has already been mentioned: how both the lung and the colony-mound complex mediate
respiratory gas exchange when ventilation does not extend to the entire structure. In an
impedance-driven system, ventilation does not have to: the AC energy need only penetrate
deeply enough to modify the mixed-phase region that limits the global function: gas
exchange. There are other interesting aspects of AC systems, however, that not only uncover
novel mechanisms for how termite mounds work, but that can inspire entirely new kinds of
biomimetic designs.
For example. so-called pendelluft ventilation (literally, air pendulum) enhances gas
exchange across the mixed-regime region of lungs through weakly-driven bulk flows of air
between alveolar ducts and between the fine bronchi (Figure 7, [17, 18]). We believe there is
a pendelluft in termite mounds as well, driven by an interaction between buoyant forces
generated by the colony, slow transients in turbulent wind energy that penetrate to the lower
chimney and subterranean tunnels and the rapid transients that drive flows in the superficial
21
Each gallery contains a fungus comb where the colony’s fungi are cultivated, and a colony can have up to a hundred or so
fungus combs. Each fungus comb contributes about a watt to the colony’s total metabolism, and the heat and water vapor
thus produced impart buoyancy to the nest air. This is the buoyant force that Martin Lüscher believed could drive
thermosiphon circulation.
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Fig. 7. Pendulluft flow in the terminal and small airways of the lung.
tunnels (Figure 8). In the lower reaches of the chimney and deep reticulum, there is a steady
upward buoyant force imparted to the air by the colony’s excess heat production. In the
surface conduits and superficial reticulum, flow is driven by fast transients in turbulent winds.
Depending upon wind speed, wind direction and the distribution of surface porosity on the
mound, this can impart either a downward or an upward pressure on the peripheral parts of the
mixed regime phase. Similarly, slow wind-induced transients can impart either a downward or
an upward pressure on air deep within the chimney and reticulum. The end result of these
complicated interactions is a pendelluft that drives slow quasi-tidal air movements in the
chimney and lower parts of the mound interior, enhancing exchange between the nest and
mound [15].
Another interesting impedance-based mechanism involves so-called high-frequency
ventilation, or HFV [20]. This is a respiratory therapy that is used to sustain gas exchange in
lungs that have suffered mechanical damage and cannot sustain the large volume changes that
normally accompany respiration. High frequency ventilation imposes minuscule volume
changes on the lung, but at a much higher frequency, 10-20 Hz as opposed to the normal
ventilation frequency of 0.2 Hz. According to one theory, HFV works by driving the lung at
the resonant frequency of the airways, enhancing diffusion and promoting pendelluft
ventilation [19, 21].
A form of high-frequency ventilation may also occur in termite mounds, but here driven by
particular bandwidths of the frequency spectrum of turbulent winds. The extensive array of
large-calibre long tunnels in termite mounds can extend for more than 2 meters in length.
These resonate strongly at frequencies of about 20-30 Hz, which sits comfortably within the
frequency bandwidth of turbulent winds, typically 1-100 Hz. If the mound’s tunnels are
“tuned” to capture the AC wind energy in this narrow frequency band, it may set air in the
tunnels resonating, driving a kind of HFV that could promote gas exchange without large bulk
flows of air through the nest. More likely, however, is a structural distribution of wind capture
that matches a distribution of resonant frequencies. For example, the air spaces in the mound
offer a variety of path lengths for transient wind energy to follow, ranging from a few
centimeters in the superficial egress tunnels, to meters in some of the deeper and larger caliber
tunnels. Thus, transient winds at the upper end of the frequency spectrum could do work in
the shorter superficial tunnels, while lower frequency transients do work in the deeper and
longer tunnels.
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This opens the possibility for discriminatory mass transfer mechanisms in termite mounds
(and termite-inspired buildings) similar to those that operate routinely in lungs. Evaporative
cooling through panting works this way, for example. Panting cools a dog by elevating the
rate of evaporative mass loss from the mouth and lungs, driven by an increased lung
ventilation [22-25]. This poses a physiological quandary: how to increase water vapor flux
without simultaneously increasing carbon dioxide flux, which could cause severe upsets of the
body’s acid-base balance. The quandary is resolved by the lung’s impedance. Driving the
lungs at the resonant frequency of the thoracic cage increases the lung’s impedance.
Ventilation therefore preferentially enhances evaporation from the upper respiratory passages.
The lung’s elevated impedance to these high frequencies leaves flux at the deeper, mixed
regime level unchanged.
Fig. 8. Hypothetical pendelluft ventilation in the termite mound and nest. Top. Array of forces acting on the
deep air masses in the mound and nest. Middle and bottom. Pendelluft flow that arises in response to
variation in wind speed and direction.
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Similar discriminatory schemes may operate in termite mounds too. For example, termites
tightly regulate the nest’s water balance, which is often undermined by percolation of ground
water into the nest following rains [26, 27]. At the same time, termites also tightly regulate the
concentrations of oxygen and carbon dioxide within the nest [15]. Termites are thus faced
with a physiological quandary similar to that panting dogs must face: how to evaporate water
faster from the nest without simultaneously disrupting the balance of respiratory gases.
Termites accomplish this by actively transporting water to the superficial parts of the mound
in wet soil, where it is deposited around the egress tunnels. Because it is precisely these
regions that should be ventilated most strongly by rapid wind transients, evaporation can be
enhanced without also increasing respiratory gas flux.
5
How buildings can be like lungs
This enhanced conception of how termite mounds work is immensely liberating because it
offers a veritable universe of new termite-inspired building designs. No longer need such
designs be constrained by the long-prevailing models of induced-flow and thermosiphon
flow: a good thing, since these mechanisms rarely operate in natural mounds anyway. In
contrast, a clear vision of how termite mounds actually work literally opens a whole new
spectrum of wind energy to explore and exploit.
Consider, for example, the traditional conception of the wall. In most building designs,
walls are erected as barriers to isolate spaces: internal spaces from the outside world, internal
spaces from one another and so forth. Yet spaces, if they are to be occupied and used, cannot
be isolated. Resolving this paradox is what forces building designs to include infrastructure—
windows, fans, ducts, air conditioning, heating etc—all essentially to undo what the erection
of the walls did in the first place. In short, the paradox forces building design toward what we
call the “building-as-machine” paradigm (BAM).
Living systems, which also are avid space-creators, resolve the paradox in a different way:
by erecting walls that are not barriers but adaptive interfaces, where fluxes of matter and
energy across the wall are not blocked but are managed by the wall itself [28, 29]. This is
illustrated dramatically in the complex architecture of the interface that termites build—the
mound—to manage the environment in their collectively constructed space—the nest [30].
New rapid manufacturing and free-form fabrication techniques make it feasible to build
walls that incorporate some of these design principles. Imagine, for example, porous walls
that are permeated with a complex reticulum that, like in the termite mound, acts as a lowpass filter for turbulent winds. In this instance, an interior space of a building could be windventilated without having to resort to tall chimneys, and without subjecting the inhabitants to
the inconvenient gustiness that attends to the usual means of local wind capture, namely
opening a window. Now, it is the windows that are the barriers and the walls that connect the
inhabitants to the world outside. Or, imagine a cladding system that mimics the mound’s
complex interface at the surface conduits and egress tunnels (Figure 9). One could employ
such claddings as whole-building wind-capture devices, which greatly expands a building’s
capacity for wind capture. Or, imagine a wall that is tuned for differential mass exchange
where the high-frequency components of turbulent winds can evaporatively cool a porous
wall’s surface layers and provide natural cooling for air forced through the walls by wind’s
lower-frequency components. The possibilities, we hope you will agree, are large.
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Fig. 9. Some imagined biomimetic designs. Top left. The surface conduit-egress tunnel complex. Top right.
A rendering of a building enveloped by porous “surface conduits.” Bottom. The block elements for an
artificial surface conduit.
6
Beyond biomimicry
Indeed, the possibilities may be more than large: they may be vast. This is because the
termite mound is not simply a structural arena for interesting function. It is itself a function,
sustained by an ongoing construction process that reflects the physiological predilections of
the myriad agents that build and maintain it. The mound, in short, is the embodiment of the
termites’ “extended physiology” [28, 31, 32]. This raises the intriguing idea that building
design can go “beyond biomimicry”, to design buildings that do not simply imitate life but are
themselves “alive” in the sense that termite mounds are.
Realizing the living building is predicated upon there being a clear idea of what
distinguishes living systems from non-living ones. Unfortunately, most of the criteria that are
commonly put forth by biologists—cellular organization, replication, heredity, reproduction,
self-organization, low entropy—are not very informative for building designers. Remarkably,
they are not even particularly helpful in the life sciences. Reproduction, for example, is not a
useful criterion for recognizing living systems, such as the biosphere, that do not reproduce.
Nor is a concept like self-organization much help: many complex non-living systems, like
clouds, are self-organizing, so how are these to be distinguished as not-life? Fortunately, there
is one feature that reliably distinguishes life in a variety of contexts and scales. That is
homeostasis, the tendency of living systems to gravitate toward a particular adaptive state in
the face of disruptive perturbations. Realizing the living building therefore means realizing
the homeostatic building.
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The idea of homeostasis is nothing new to architects and engineers, of course: it is standard
practice to outfit buildings with systems to regulate particular properties of the built
environment: temperature, humidity, air quality and so forth. The focus here is on machines
that do work to manipulate a property through negative feedback control (Figure 10). Thus, a
property is sensed, its deviation from some desired value is assessed, and a machine is
activated that does work to offset the deviation. Such systems range in complexity from
simple house thermostats to sophisticated Building Energy Management Systems, but all have
in common that they are firmly rooted in the building-as-machine design tradition.
Fig. 10. The standard negative feedback model for regulating the built environment
Homeostasis is more than simply self-regulation, however. It is a fundamental property of
life that, among other things, confers upon living systems an impressive capability for
emergent self-design [29]. Thus, regulation of an environmental property—the essence of the
building-as-machine—is but one of many outcomes of a larger systemic homeostasis that
engages every aspect of the system’s architecture and function.
The termite “extended organism” is a remarkable example of this capability. A termite
colony’s oxygen demand varies considerably with colony size: small colonies may comprise a
few thousand individuals, while the largest colonies may have populations upwards of two
million [33]. Despite this large variation in demand, oxygen concentrations do not differ
appreciably with colony size: oxygen concentrations in very large colonies are similar to those
in much smaller colonies (Figure 11, [15]). Yet, there is no machine in the termite mound that
does the work to offset the perturbation that a negative feedback system might demand. Nor is
there any evidence of an “oxygen-stat”: termites are not particularly sensitive to quite large
oxygen perturbations. How, then, is oxygen concentration regulated?
Part of the answer is that it is not simply the property of oxygen concentration that is
regulated. What is regulated, rather, is multiphase processes of one outcome is a steady
oxygen concentration. Because the mound is an extended organism, this process extends to
the mound, which is itself a process. Thus, mound structure is as impressively regulated as
oxygen concentration is.
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Fig. 11. Oxygen concentration in several nests of Macrotermes michaelseni. Symbols represent means +/- 1
standard deviation. Mound size is a surrogate for colony metabolic demand.
How termite colonies manage this seamless integration of structure and function remains
largely obscure, but some interesting features are starting to emerge. There is a common link,
for example, in the termite-mediated movement of soil that makes the mound both process
and structure: this is why it is possible for the mound’s structure to reflect the termites’
collective physiology. Understanding the termite colony extended organism therefore
involves understanding what guides this ongoing termite-driven stream of soil through the
mound.
Surprisingly, negative feedback appears to play only a minor role. Rather, there is a kind of
swarm intelligence at work. Soil translocation is organized into discrete foci of intense
activity that is driven by a multiplicity of positive and negative feedback loops involving
termites, the structures they build and the intensity of local AC perturbations of the
environment. To complicate matters, the multiple foci compete with one another for workers,
with more intensely active foci drawing workers away from less intense foci, the outcome of
the competition both determining and being determined by the structures that result. To
complicate things further, the entire process is modulated by the availability of liquid water.
The building-as-machine paradigm cannot quite capture this kind of seamless integration,
largely because it regards structure as something distinct from function. It is therefore
unlikely that the living building can emerge from this design tradition. In living systems,
however, no such distinction is possible: structure is function and function is structure. At
present, simply stating this offers little practical value in telling us how to realize a living
building, but it at least points us the right way: toward buildings that are extended organisms,
where function and structure meld, and are controlled by the over-riding demands of
homeostasis.
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Fig. 12. Model for swarm regulation of the nest environment. Building is driven by multiple foci of intense
soil movement that can drive soil transport autonomously. The various foci also compete with one another
for building agents (i.e. termites). A focus is initiated by an AC perturbation, and is sustained by a positive
feedback loop called stigmergy. AC perturbations also sustain the focus of building. As building proceeds,
the level of AC perturbation abates. Building will continue being driven by stigmergy, but this has a natural
decay time.
Acknowledgements. This research was supported by grants from the National Science
Foundation (USA) to JST and the Engineering and Physical Sciences Research Council (UK)
to RCS. We are also grateful to the National Museum of Namibia and the Ministry of
Agriculture of the Republic of Namibia, which provided logistical and technical support for
this work.
References
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3. Darlington, J.P.E.C., The structure of mature mounds of the termite Macrotermes
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17. Engel, L.A. and M. Paiva, eds. Gas Mixing and Distribution in the Lung. Lung Biology in
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20. Chang, H. and A. Haif, High frequency ventilation. A review. RESPIRATION
PHYSIOLOGY, 1984. 57: p. 135-152.
21. Tanida, Y., Pendelluft effect on gas exchange in high-frequency ventilation. Japan Society
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27. Turner, J.S., et al., Termites, water and soils. Agricola, 2007. 2006(16): p. 40-45.
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31. Turner, J.S., Extended phenotypes and extended organisms. Biology and Philosophy,
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Simulation of Innovative Climate Control Strategies
Using Passive Technologies
Bas Hasselaar1, Wim van der Spoel1, Regina Bokel1 and Hans Cauberg1
1 Faculty of Architecture, Chair of Climate Design, Delft University of Technology,
Delft, The Netherlands
Abstract
The Climate Adaptive Skin acknowledges the advantages of naturally ventilated buildings, but also takes the benefits of
mechanical ventilation into account. It is intended to be able to provide a comfortable indoor climate to the user, while using
as little primary energy as possible. Building services are integrated into the façade itself at office-room scale, making the
office adjacent to the façade independent of centralised HVAC systems and the indoor environment optimally adjustable by
the user. By using technologies and materials that are able to react to the changing thermal environment, such as phase
change materials (PCM) and thermotropic glass, the energy consumption is reduced to a minimum. The resulting façade has
few moving parts, requires little maintenance and is able to acclimatise its bordering office space almost autonomously.
Keywords
adaptive; façade; simulation; PCM; thermal comfort
1. Introduction
In most modern buildings, a comfortable indoor climate is created using energy consuming
centralised building services that provide heat or cold, ventilation air and often regulate
artificial lighting. The perception of this comfort is based on standards that regard comfort as
a set of variables, which can be set at a certain value that will provide an optimal comfort
level for 95% of the users.
Recent insights [1] into thermal comfort indicate that thermal perceptions are affected by
recent thermal experiences and expectancies. In other words, people accept higher
temperatures in summer and cooler temperatures in winter. This however applies mostly to
naturally ventilated buildings; people tend to be less tolerant towards varying indoor
temperatures if a building is fully air conditioned.
A new façade concept is under development [2] that takes a different approach to both climate
control and user comfort perception. Adaptive temperature limits are taken as guidelines to
create a façade that changes with the outdoor climate, optimally utilising outdoor influences
as an aid to create a comfortable indoor climate while minimising the amount of primary
energy to condition the indoor environment.
2. The Climate Adaptive Skin
The basic concept behind the facade is that it is able to create a comfortable indoor climate
using both the indoor and outdoor climate. This means that characteristics of the indoor office
space, i.e. presence of internal heat sources, a need for fresh air and daylight, and room
temperature between certain boundaries, are used and combined with outdoor (temperature
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Technologies for Intelligent Building Services
and solar) influences to create a comfortable indoor climate, with the goal to minimise
(primary) energy consumption.
Besides the energetic desires for the façade, there are additional conditions formulated, such
as a limited façade width and a simple, ‘robust’ façade design to minimise maintenance and
reduce the likelihood of malfunction. These conditions are chosen as a framework within
which the research takes place.
The limited façade width, or thickness, reduces its footprint, and leaves more building to the
architect or user. Also, because of its limited thickness, it is easier to attach to the building,
reducing potential constructional difficulties. The desire to create a ‘simple’ façade that can
function, i.e. create a comfortable indoor climate, autonomously to a large extent, while
requiring little maintenance, has its implications. A façade independent of warm/cold
air/water needs no pipes or ducts for climate control. No ducts or pipes means that installation
of the façade is much easier, quicker, and that there is no need for a lowered ceiling or duct
along the façade to accommodate the space these services require. In short, the whole building
layout can be a lot simpler if the façade can provide a comfortable indoor climate without the
need for supplied air or water. By choosing technologies that are relatively low-tech, the
chance of malfunction is reduced because fewer moving parts or electronics means less
maintenance.
The main technologies of the façade are schematically shown in Fig. 18, with the full façade
on the right and an enlargement of the bottom part, where most of the installations are, on the
left.
1. heat exchanger
2. PCM stack
3. fan
Fig. 18. Schematic vertical cross-section through the Climate Adaptive Skin
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Ventilation
There are three components that play an important role in the provision of fresh air: an air to
air heat exchanger (number 1 in Fig. 18), two tangential fans (numbers 3 in Fig. 18) and a
stack of PCM (Phase Change Material) plates with a phase change temperature range of 1719°C (number 2 in Fig. 18). Fresh air is drawn directly from outside, preheated by the heat
exchanger and then forced through the PCM plates before being distributed into the indoor
environment. Stale air is drawn from the indoor environment at the top end of the ventilation
unit, forced through the heat exchanger where thermal energy is exchanged with the incoming
outdoor air, before being discharged through the cavity to the outside.
Users are given the option to manually open the window for additional ventilation and for the
psychological advantage of being able to control their immediate environment.
Light
The part of the façade above the ventilation units is almost fully transparent. This is beneficial
for two reasons: provision of daylight which reduces the need for additional artificial lighting,
and the reduction of glare caused by large luminosity differences between transparent and
non-transparent parts of the facade.
To prevent potential overheating in summer, the glass in between the two cavities is equipped
with thermotropic glass, which transforms from completely transparent to translucent milky
white once a certain threshold temperature is exceeded. This not only reduces unwanted heat
gains through solar irradiation, but also reduces strong direct sunlight and replaces it with
neutral white, diffuse light. Once the temperature drops below the threshold temperature
again, the glass returns to its transparent state. The inner glass face is equipped with
electrochromic glass to give users the possibility to change the transparency of the façade
from completely transparent to almost black at will.
Heat/cold
The acclimatisation of the indoor temperature takes place in a number of ways: first of all, the
façade is supposed to be well insulated, and air tight. Ventilation air enters the room at a near
constant 18°C, which, in combination with the indoor heat sources (people, equipment and
lighting) results in a comfortable indoor temperature.
The PCM has both a heating and cooling task, depending on the outdoor temperature. In
summer, the PCM cools outdoor air down to 18 degrees during the day, while using night
ventilation to regenerate its cooling capacity during the night. In winter, the PCM heats up the
incoming ventilation air during the day, while at night, when necessary, electric heating coils
or foils regenerate the PCM’s heating capacity using lower priced night electricity and
shaving off peak daytime demand.
As such, the façade is able to function using nothing but electricity, which could be generated
using photovoltaic panels at the bottom part of the façade. Even though energetically and
exergetically the use of electricity for heating might not be the optimal solution, it simplifies
the design and connections of the façade to a great extent.
3. Simulation and operation
To get an indication of how the façade performs, it is simulated using the Mathworks program
Simulink. Since one of the main features of the façade is the utilisation of PCM in the
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conditioning of ventilation air, the initial model was based on the thermal interaction between
air and PCM. From there on, the model has been expanded, and extra features, such as the
heat exchanger, the thermotropic window and a basic indoor space, have been defined and
added. There are quite a number of variables that play a role in the operation of the façade and
that have an influence on the outcome of the simulations. It should be noted that the
performance of the façade is simulated with the Dutch climate in mind, using the weather file
for 1995, which had a very warm summer.
To be able to see what influences individual components have on the total performance of the
façade, a ‘default’ situation or setting has been assumed from which changes in the settings
are assessed. This default situation has the following settings (Table 3):
Table 3. Default settings simulation model.
Efficiency heat exchanger [%]
60
%
Temperature windows open [°C]
22
°C
Temperature windows close [°C]
21
°C
Influence openable windows [added to ventilation rate]
0.5
+ vent rate
Thermotropic glass colour change transparent to white [°C]
23
°C
Thermotropic glass colour change white to transparent [°C]
22
°C
Phase change temperature range [°C]
17-19
°C
Dimensions PCM [m] / number of layers
0.005*0.6 / 12
m/
Thermal mass PCM [rho*lambda]
1500*1
rho*lambda
Second batch of PCM temperature range [°C]
-
°C
Dimensions second batch phase change [m]
0.005*0
m
Ventilation rate day [m3/s]
0.02
m3/s
Ventilation rate night [times daily rate]
2
* day rate
Temp difference indoor-outdoor night ventilation [°C]
2
°C
Minimum outdoor temperature for night ventilation [°C]
10
°C
U-value glass [W/m2K]
0.85
W/m2K
Power night heating [W]
40
W
Conditions night heating: Te PCM below? [°C]
18
°C
Internal heat load [W/m2]
20
W/m2
Energy heating per year [kWh]
69
kWh
Heat exchanger
The stale air is used to preheat the incoming ventilation air using a cross-flow heat exchanger
to reduce the electricity demand for heating. In earlier simulations without heating or a heat
exchanger, it was shown that additional heating is required for a large part of the year.
The heat exchanger in the simulation model uses the difference between indoor and outdoor
temperature as a basis value and multiplies that by the efficiency of the exchanger, estimated
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
to be 60%. This value is added to the incoming ventilation air temperature before going into
the PCM stack.
PCM
Because PCMs do not change phase at a specific temperature, but at a temperature range, e.g.
between 17 and 19°C, the latent heat capacity associated with the phase change should be
divided over this range. Two methods have been simulated: one with the total latent heat
capacity evenly distributed over the whole range, meaning that every temperature within the
range has the same latent heat capacity, and one with a peak latent heat capacity in the middle
of the phase change range, meaning that the latent heat capacity changes from 0 at 17°C to
maximum at 18°C and back to 0 again at 19°C. In both cases, the total amount of latent heat
capacity is the same, and simulations show very little difference in thermal behaviour of the
total façade between both options.
To make sure that sufficient thermal energy is exchanged between the air and the PCM plates,
the plates are simulated to have a thickness of 5 mm. with an air flow of 5 mm. along them.
The height of the PCM, or the distance the air is in contact with the PCM, can be chosen, but
is set to be 0.6 m in the default situation.
Openable windows
The façade is fitted with manually openable windows that enable additional natural
ventilation on top of the mechanically supplied fresh air from the PCM unit.
Although the operation of the windows is user dependent, the influence of the additional
ventilation is used in the simulation model. Windows are supposed to be opened when the
indoor temperature exceeds 22°C and closed when the outdoor temperature sinks below 21°C.
In all cases, the indoor temperature needs to be at least the same as, or higher than, the
outdoor temperature. The influence of open windows is assumed to be an increase in the
ventilation rate of 0.5 per hour.
Night ventilation
The façade is initially aimed at office use. This means that during normal use, daytime hours
are considered to be from 7 am to 7 pm, while night time is from 7 pm to 7 am. The
performance of the façade is adjusted to these working hours, meaning that for example the
capacity of the PCM is aimed at daytime use, to be regenerated during the night.
Night ventilation, or night flushing, is used to shed unwanted thermal energy accumulated in
the PCM during the day by forcing cool outdoor air along the PCM during the night. Since
there is a chance that the temperature difference between phase change and the outdoor
temperature is lower during the night than during day, the ventilation rate is doubled during
the night to increase heat exchange.
There are two additional parameters involved with night ventilation: the temperature
difference between the operational temperature of the indoor climate and the outdoor climate,
and the outdoor temperature, with the operational indoor temperature being the temperature
occupants experience when present.
The temperature difference between the two should be at least two degrees Celsius. To make
night ventilation beneficial, the outdoor temperature should be at least two degrees lower than
the indoor temperature, to prevent unnecessary energy consumption by the fans that force the
air flow.
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The outdoor temperature should be at least 10°C. This limit is to prevent excessive heat loss
through night ventilation, to such an extent that additional heating is necessary to make up for
the heat lost. Besides, if outdoor temperatures reach below 10°C at night, it is unlikely in the
Dutch climate that there will be a large need for night ventilation anyway, since daytime
temperatures will not have exceeded the upper limit of the phase change much.
Night heating
In the Netherlands, the average temperature throughout the year is just under 10°C, while a
comfortable indoor temperature is aimed to be at least 20°C. This suggests that, especially in
winter, there will be need for additional heating of the PCM to enable it to stay in phase
change stage and utilise its latent heat storage to condition incoming ventilation air.
The heating of the PCM plates happens through electric heating foil or strips that heat up
when an electric current is applied to them. Because of the buffering capabilities of PCM, it is
possible to heat the PCM during the night, using cheap night electricity and reducing peak
energy demands during the day, especially in the morning.
The PCM will be heated during the night in case the temperature of the ventilation air exiting
the PCM stack drops below 18°C. Since the phase change temperature ranges from 17 to
19°C, an exit temperature of below or equal to 18°C indicates that a significant part of the
PCM has solidified and that insufficient energy is available to heat the ventilation air to above
the middle of the phase change temperature region. By adding heat, the optimal equilibrium
between solid and liquid can be restored, so that maximum thermal energy is available for
both heating and cooling.
By adding the extra condition that the indoor operational temperature needs to be 20°C or less
before night heating is used, the energy consumption of the façade can be reduced, but is
traded for comfort, as simulations indicate that in winter the minimum indoor temperature can
drop below 20°C, reaching as low as 18°C on several occasions.
Of course, this is in a simulated environment, where the phase change and thermal behaviour
of the PCM is uniform and constant. Testing in a controlled environment using commercially
available PCM plates is necessary to validate the outcome of the simulations.
Thermotropic glass
To prevent potential overheating in summer, the glass is simulated to display a change in gvalue from 0.58 to 0.08 at an indoor temperature of 23°C. Effectively this means that at 23°C
shading is lowered, or that thermotropic glass [3] is used. The façade is also equipped with
an electrochromic layer to give users the possibility to change the transparency of the façade
from completely transparent to almost black at will.
The U-value of the façade is supposed to be equal of the best insulating glass used in the
design, taking the large amount of glass of the façade into account. This U-value is supposed
to be 0.85 W/m2K. To prevent overheating from excessive solar irradiation, thermotropic
glass is utilised which changes its g-value from 0.58 to 0.08 once a threshold temperature of
23°C is reached, meaning that, for simulation sake, the glass changes from transparent to
translucent at 23°C, and changes back at 22°C. The glass in the simulation model responds to
the operative temperature of the room, and not to the actual temperature of the glass. The
temperature of the glass is dependent of the indoor temperature, the outdoor temperature and
the amount of sunlight absorbed and reflected. The model will need further refinement to take
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
glass temperature into account instead of room temperature, since the temperature at which
the colour of the glass changes has a great influence on the operative temperature of the room.
Indoor space
The nature of the façade allows for the indoor space to be free of a lowered ceiling, meaning
that the thermal mass of both the floor and the (concrete) ceiling can be used in the
determination of the indoor climate in the simulations. The façade is not designed to have a
specific width, but designed to be able to condition the adjacent office space, which is a
standard 5.4 m. deep. As such, it can be multiplied by any number in horizontal direction; the
width of the façade is therefore chosen to be 1 metre.
For the indoor heat production an average of 20 W/m2 for people, equipment and lighting is
taken. The transparent part of the façade equals roughly 2 m2 through which solar irradiation
heats up the indoor climate, how much depending on the weather and on the g-value of the
glass, which is temperature related.
4. Simulation results
When a full year is simulated with the input listed in Table 3, the following results can be
observed (Fig. 19 and Fig. 20): the façade is very well capable of keeping the indoor climate
within comfort limits. Save for approximately 5 days in summer, the operational indoor
temperature stays within the bandwidth of 20-24°C.
st
st
Fig. 19. Indoor temperature (black) against outdoor temperature (grey) from Jan.1 to Dec 31
st
st
Fig. 20. Indoor temperature from Jan.1 to Dec 31
The influence of the g-value change of the thermotropic glass at 23°C can be very well
observed in Fig. 20, where, for a large part of the year, the indoor temperature is capped at
23°C.
In summer, the capacity of the PCM is insufficient to keep the indoor temperature below
24°C, and for a few days the temperature shoots toward a maximum of almost 28°C. This is
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Technologies for Intelligent Building Services
mainly because the outdoor temperature does not get below 19°C, not even at night, as can be
observed in Fig. 19, meaning that the PCM cannot shed unwanted heat during the night, and
cannot store low temperatures to cool during the day.
Optimising the parameters
Using the default settings mentioned in Table 3 as a starting point, the influence of each of the
parameters could be examined, by simulating values both higher and lower than the default
setting. As such, the influence of each setting could be determined by studying various output
graphs and comparing the energy consumption. A summary of the changed settings of the
different parameters and their influence is shown in Table 4.
Table 4. Summary of the changed settings and their influence.
#
Change
Energy
[kWh/y]
Influence
energy/comfort
1
Efficiency heat exchanger 100%
59
+
+
2
Efficiency heat exchanger 0%
86
-
-
3
Heat exchanger always used
13
++
-
4
PCM amount reduced by 50%
76
-
-
5
PCM amount increased by 50%
71
0
+
6
Add. 50 % PCM Change at 23°C
67
0
0
7
Influence vent. rate windows 0
70
0
-
8
Influence vent. rate windows +1
69
0
0
9
Windows open at 23°C close at 19°C
77
-
-
10
Windows open at 25°C close at 22°C
30
++
-
11
ΔT in-out for night ventilation 0°C
69
0
0
12
ΔT in-out for night ventilation 3°C
69
0
0
13
ΔT in-out for night ventilation 4°C
69
0
0
14
ΔT in-out for night ventilation 5°C
71
0
-
15
ΔT in-out for night ventilation 6°C
70
0
-
16
Night vent. rate 0 times daily rate
47
++
--
20
Night vent. rate 1 times daily rate
56
+
-
21
Night vent. rate 3 times daily rate
83
-
+
17
Min. Te for night ventilation 5°C
109
--
-
18
Min. Te for night ventilation 15°C
50
++
--
19
Min. Te for night ventilation 12°C
58
+
-
22
Power night heating 20 W
65
-
-
23
Power night heating 60 W
72
0
0
24
Extra cond. night heating if Ti<20°C
33
++
--
25
Extra cond. night heating if Ti<22°C
67
0
0
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26
Only cond. night heating if Ti<22°C
95
--
-
27
Cond. night heating Te PCM<19°C
106
--
--
28
Cond. night heating Te PCM<17°C
55
+
-
29
Therm. glass changes at 24-25°C
73
-
-
30
U-value glass is 1.0 W/m2K
31
68
0
0
2
64
+
--
2
U-value glass is 1.5 W/m K
32
U-value glass is 6.5 W/m K
53
+
--
33
As 32 + night heating if Ti<22°C
148
--
--
34
Daytime ventilation rate 0,008 m3/s
32
++
--
35
Daytime ventilation rate 0,04 m3/s
114
--
--
36
Daytime ventilation rate 0,012 m3/s
47
++
--
37
Daytime ventilation rate 0,016 m3/s
60
+
-
38
Internal heat load 15 W/m2
68
0
0
After all the different parameters were simulated individually, an attempt was made to
optimise the façade performance by selecting the parameters that have the largest influence on
both the energy consumption of the façade and the indoor climate, and adjusting them in such
way that the changes were beneficial.
The simulations made it apparent that the heat exchanger (HE) is a vital component of the
façade in terms of energy consumption, and that its performance is quite dependent on and
sensitive to the temperature at which it is switched on or off: the PCM phase change
temperature is simulated to be between 17 and 19 degrees, with the largest thermal capacity at
18°C. The air temperature exiting the PCM stack, in other words, the temperature of the air
that is being distributed into the office space determines whether outgoing stale air passes
through the heat exchanger or not. If the ventilator forcing exhaust air through the HE is
switched off when the ventilation air temperature is 18°C, the effect of the HE is very limited.
However, if it is switched off when the temperature is 19°C, its effect is enormous: a drop in
energy consumption for heating by more than 80%. The consequence however is that during
summer indoor temperatures exceed 24°C more often. By switching off the ventilator for the
discharged stale air at 18.5°C, effectively bypassing the HE, high indoor temperatures are
reduced to a minimum, although still higher compared to the default situation, while a
reduction in energy consumption of almost 80% can still be achieved.
By making night heating of the PCM dependent of both the indoor temperature and the
ventilation air temperature exiting the PCM stack, the energy consumption for heating can be
reduced even further: if heating is turned on only during the night when the indoor
temperature drops below 20°C and when the ventilation air temperature exiting the PCM
stack drops below 18°C, the energy consumption can be reduced by another 40% compared to
the previous situation
The energy demand can be lowered even further if the condition that the ventilation air
temperature exiting the PCM stack needs to be at least 18°C is changed to at least 17°C. This
however has an important influence on the minimum indoor temperature and therefore
comfort experience of the user: it is lowered to levels below 18°C on several occasions, which
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is unacceptable for an office environment. This fortunately can be remedied by making the
ventilation rate adjustable: if the ventilation rate in winter is 2, effectively meaning a fresh air
supply per façade element of 8 l/s, there are virtually no problems with too low temperatures.
Energy demand for heating can be lowered to almost nothing: per year a simulated
consumption of only 1 kWh, as listed in Table 5, which gives the optimised values of the
different settings in the simulation model.
5. Conclusions
Simulations suggest that it should be possible to ventilate an office space and create
comfortable indoor temperatures throughout the year using passive technologies without
consuming any primary energy. Although it will be necessary to provide electricity to power
the fans that force the ventilation and, very occasionally, to heat the PCM, if a photovoltaic
panel would be fitted in combination with a battery, the façade could theoretically be able to
function autonomously throughout the year.
The next step is to build prototypes of both the individual systems and a full façade to test and
validate the simulation results.
Table 5. Optimised settings simulation model.
Efficiency heat exchanger / HE off if Te PCM above 18.5°C
60
%
Temperature windows open
22
°C
Temperature windows close
21
°C
Influence openable windows [added to ventilation rate]
0.5
+ vent rate
Thermotropic glass colour change transparent to white
23
°C
Thermotropic glass colour change white to transparent
22
°C
Phase change temperature range
17-19
°C
Dimensions PCM / number of layers
0.005*0.6 / 12
m/
Thermal mass PCM
1500*1
rho*lambda
Second batch of PCM temperature range
-
°C
Dimensions second batch phase change
0.005*0
m
Ventilation rate day
0.008 – 0.02
m3/s
Ventilation rate night [times daily rate]
2
* day rate
Temp difference indoor-outdoor night ventilation
2
°C
Minimum outdoor temperature for night ventilation
10
°C
U-value glass
0.85
W/m2K
Power night heating
40
W
Conditions night heating: Te PCM below? & Ti below?
17 &20
°C
Internal heat load
20
W/m2
Energy heating per year
1
kWh
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References
1. Linden, A.C. van den, Boerstra, A.C., Raue, A.K., Kurvers, S.R., De Dear, R.J.: Adaptive
temperature limits: A new guideline in The Netherlands a new approach for the assessment
of building performance with respect to thermal indoor climate. Energy and Buildings, vol.
38, (2006) 8-17
2. Hasselaar, B.L.H., Spoel, W.H. van der, Bokel, R.M.J., Cauberg, J.J.M.: Simulation of the
thermal performance of a Climate Adaptive Skin. CISBAT conference proceedings (2007)
55-60
3. Watanabe, H.: Intelligent window using a hydrogel layer for energy efficiency. Solar
Energy Materials and Solar Cells, vol. 54, (1998) 203-211
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Automated Assessment of Buildings, based on the
Deployment of Wireless Networks of Sensors
Chee Yeew Yong+, Duncan Wilson*, Derek Clements-Croome**, Min Wu**, Hamid Asgari+, Richard Egan+
+ Thales Research & Technology (UK) Ltd., Worton Drive, Reading, Berkshire RG2 0SB, U.K.
{Chee-Yeew.Yong, Hamid.Asgari, Richard.Egan}@thalesgroup.com
* Arup, 13, Fitzroy Street, London W1T 5BQ, U.K.
[email protected]
** School of Construction Management & Engineering, University of Reading,
Whiteknights, Berkshire RG6 6AY, U.K.
{D.J.Clements-Croome, M.Wu}@reading.ac.uk
Abstract
This paper reports on a trial carried out to deploy a wireless sensor network (WSN) in a real building over a period of four
weeks for the CMIPS 22 project. Within this project, three software tools have been developed: a real-time building
assessment tool, a visualisation tool, and a WSN middleware package. The overall aim has been to identify potential issues
for a more formal field deployment to be carried out in 2008, to test prototype sensor platforms, and to collect sensor data for
use by software tools. This paper presents the developed prototype visualisation tool, discusses some results derived from the
environmental sensor data, and identifies the lessons learnt for use in future deployments. The most important observations
made were: (1) different reporting strategies are required for different sensor platforms to extend battery life; (2) sensors
should be protected from interference by occupants; (3) the variety of sensor platforms available can lead to inconsistent
sensor data obtained from essentially co-located sensor platforms.
Keywords
Building assessment, sensor networking.
1. Introduction
CMIPS (Co-ordinated Management of Intelligent Pervasive Spaces) is an ongoing project
with members from both industry (construction and ICT 23) and academia. The principal
objectives of the project are energy efficiency and well-being of occupants; in the context of
leveraging the current state-of-the-art in wireless sensor networks and building assessment
systems to enable the optimisation and assessment of buildings. Having these principal
objectives, the project is looking at producing a real-time sensor-based building assessment
tool, which derives physical environment information from a building-wide environmental
wireless sensor network.
Building assessment is the process of rating a building in accordance to certain pre-defined
standards or guidelines. Building assessment is currently a time-consuming exercise involving
manual procedures, with the result that assessments are carried out infrequently, if at all. The
CMIPS view is that assessment can be an invaluable tool for the effective management of
22
CMIPS is supported in part by U.K.’s Technology Strategy Board (previously, the Department of Trade and Industry)
under Project No. TP/3/PIT/6/1/16218.
23 Information & Communications Technology
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Technologies for Intelligent Building Services
buildings if the process can be made easier to carry out. The architecture of the CMIPS
Building Assessment identifies a broad range of stakeholders who have different assessment
objectives, including energy efficiency of the building and well-being of the occupants.
Consequently, CMIPS has identified a number of performance indices that address these
specific assessment objectives. A phased approach to developing an on-demand automated
assessment system has been defined, based on a multi-value attribute technique, to enable
incremental development.
The CMIPS building assessment system require access to a sensor-rich environment to collect
real-time data on the state of the environment and the occupants. CMIPS envisages the use of
both environmental sensors to measure temperature, air quality, etc. and social sensors to
measure the occupants’ satisfaction levels. The CMIPS sensor networking architecture is based on
multi-hop wireless communications to ease deployment of these sensors.
2. Background
In the last two decades, intensive research has been done in the area of intelligent buildings
(IBs) [1]. An IB is defined as a building that can meet the needs of occupants and business,
and be flexible and adaptable to changes [2]. An important topic in IB research is building
assessment, as this may lead to methods for evaluating new and existing building designs, and
assist the building manager in monitoring the ‘health’ of the building. Existing building
assessment systems include the IB Rating [3], Building Intelligence Quotient (IQ) Rating
Criteria [4], IB Index [5], A Matrix Tool for Assessing the Performance of Intelligent
Buildings [6], and Design Quality Indicator (DQI) [7], amongst others.
These building assessment approaches propose to measure a building and its systems, and can
even help to improve the design of building. For example, the DQI is a toolkit that can
capture perceptions of design quality embodied in buildings [7]. It is composed of three main
elements: the conceptual framework, a gathering tool and a weighting mechanism. The
conceptual framework focuses on function, build quality and impact. The gathering tool uses
a questionnaire to collect general data about function, impact and build quality. The weighting
mechanism was developed through a simple multi-criteria assessment algorithm. The generic
questionnaire of DQI comprises over 90 statements under its conceptual framework covering:
engineering performance, durability, integration of systems, construction, design of spaces for
working, effect of building on environment, form and materials, and internal environment and
innovation.
Over 45% of energy is consumed by buildings due to the embodied energy in materials,
transportation and construction works on site, and for operation of building service systems.
However, none of these assessment systems have sufficiently addressed either the total energy
consumption of buildings or the reaction of the people. In addition, previous building
assessments were conducted manually, and thus could hardly provide feedback to either the
occupants or the facilities managers promptly. To address this issue, the CMIPS project
proposes a sensor based building assessment model to assess the energy consumption in
buildings as well as its occupants’ response to its indoor environment.
2.1 Architecture for the building assessment
CIBSE [8] suggests that the main factors that influence comfort for people relate broadly to
our senses, that is, touch, smell, vision and hearing. Thus a ‘comfortable’ building must
provide a good thermal, aural and visual environment, fresh air, warmth or cooling, no
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unwanted noise or odours, and good light. The design criteria of such a building include the
use of space, activity level, clothing, age of occupants, etc. The assessment tool developed in
the CMIPS project is to provide real time partial assessment of an office building based on its
energy consumption. The devised Sensor Based Real Time Assessment (SBR) model (see
Fig. 1) only examines temperature, humidity, lighting, and indoor air quality of the working
environment, while recognising that other factors of the working environment may have an
impact on the well-being as well. For example, the velocity air movement (draught) is
important to the comfort that a user experiences, and thus the user’s well-being; generally, the
higher the air velocity, the colder a user feels. However, it is difficult to source a low-cost air
velocity sensor that meets the requirements of the CMIPS project.
The SBR model also partially assesses a building by calculating its well-being cost index. The
model reads 12 variables, covering illumination quality, thermal quality, air quality and the
response of occupants. The well-being cost index is derived from the energy consumption
index and indoor climate index. The energy consumption index is derived from indoor air
temperature, outdoor air temperature, energy (electricity, fuel and gas) consumption, and
energy consumption rates recommended by the building regulations [9]. It mainly monitors
the thermal performance of a building. The indoor climate index monitors physical working
environment and the response of the occupants. Whilst data for energy consumption,
temperature, humidity, illumination can be captured by traditional sensors, the feedback of
occupants may be captured by a sense diary [10]. The sense diary is a touch screen electronic
device that is in development by a research team at the University of Reading. It can record
the date, the satisfactory level of the occupants on temperature, lighting, sound and indoor air
quality.
Government energy
consumption rules
Comparator
Outdoor air
temperature
Electricity, Fuel,
Gas
Indoor air
temperature
Standardised wellbeing temperature
Energy
consumption rate
Comparator
Humidity
Standardised wellbeing humidity
Humidity
comfort index
Comparator
Lighting
comfort index
Comparator
Indoor air
quality index
Indoor air quality
Standardised indoor
air quality
Sense
Temperature
comfort index
Comparator
Illumination
Standardised wellbeing illumination
Energy
consumption
rating index
General
environment
quality index
Cost
weighting
(CW)
Multiattribute
value
technique
(MAVT)
Wellbeing
cost
index
People
Fig. 1. CMIPS sensor-based real time building assessment model.
The SBR model also illustrates how energy consumption index, temperature-, humidity-,
lighting-, indoor air quality-comfort index and indoor climate index can be derived by using
the data from sensors. Two key tasks in the SBR model are to derive the cost weighting and
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Technologies for Intelligent Building Services
the weightings of the sub-factors of the indoor climate index. The cost weighting may be
derived based on data provided in [11].
3. CMIPS Field Trial
CMIPS carried out a 4-week trial that started in early June 2007. The objectives of this field
trial were to:
Test environmental sensors and their communication platform,
Identify potential issues when placing the bespoke sensors around the test site,
Gather real-time sensor data and test a user-friendly visualisation tool to present the data to
users.
The selected test site for the CMIPS field trial, and eventually for a formal field deployment,
is Arup’s main office in London. The office was refurbished in 2004. The ground floor, where
most of the employees work, is where all the sensors were placed. The layout of the ground
floor is shown in Fig. 2. The locations of the variety of sensors are shown in this figure – the
sensor types are elaborated later.
Fig. 2. Location of sensors in Arup’s main office building.
In this building, the heating is controlled via an air-handling unit (AHU) situated on the top
floor, which takes fresh air from outside and delivers conditioned air at 22 - 24°C. The
conditioned air is delivered in zones, which are controlled by thermostats. The building uses a
Tridium BMS 24 and has a TREND interface via the Arup intranet. Historical sensor data is
accessible via the Arup intranet. The BMS has a number of dedicated sensors including 9
indoor temperature sensors (some of the sensors are shown in Fig. 2), outdoor air temperature,
AHU extract temperature and volume, and AHU supply temperature and volume.
24
Building Management System
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3.1 Deployed sensor environment
During the field trial, three different wireless sensor node (WSn) platforms were deployed to
access the variety of sensors used:
•
Crossbow motes (passive sensing, 14 nodes, 84 sensor points)
•
Beasties (passive sensing, 1 node, 1 sensor point)
•
ArduinoBT (passive sensing, 4 nodes, 4 sensor points)
The Crossbow WSn was implemented using the MICAz radio processor board. The radio uses
the 2.4GHz ISM 25 band for radio communication and is compatible with the IEEE 26
802.15.4 standard. Its baud rate for radio communication is set to 250kbps. The processor
onboard is an 8-bit microcontroller. The motes are equipped with Crossbow’s MTS400 sensor
boards, which has a number of sensors including temperature, humidity, atmospheric
pressure, light lux meter and 2-D accelerometers. Each mote is programmed with Crossbow’s
supplied software that simply reports, periodically, the ADC 27 readings from all its
MTS400’s sensors to a base station. The software supports XMesh, the multi-hop, ad-hoc,
mesh networking protocol, provided by Crossbow – allowing it to reach the base station via
other motes. The reporting period is 470 seconds.
At the base station that logs any reported sensor data values, a Crossbow MIB510 serial
gateway device is connected to a computer. This is via a serial cable, and using a USB-toserial bridge at the computer. The gateway (with an attached mote) is programmed with the
standard base station program (provided by Crossbow) that also supports XMesh. The
Crossbow WSn produced on average a packet with data every 33.5 seconds. Furthermore,
there were an equal number of health and heartbeat (keep-alive) packets being transmitted
through the network approximating the network’s packet rate to 1 packet every 17 seconds.
The Beasties are simple wireless microcontroller devices developed at Imperial College that
are designed for prototyping wireless sensor node setups. Each Beastie has an 8-bit
microcontroller, low power digital radio (433MHz), power supply and an expansion bus
connector. The Beasties communicate using an autonomic network. This is a network that is
self-configuring, self-optimising (communication is optimised by device), and self-repairing
(the network adapts to take account of new devices as they are added to or removed from the
network). An Irisys People Counter sensor was deployed on the Beasties to count the number
of people coming in and out of three doors that provided access to the space being monitored.
The Arduino WSn is implemented using the ArduinoBT sensor boards. These boards use the
Bluetooth IEEE 802.15 standard for radio communication. This deployment architecture does
not require a base station as a single computer connects to each of the Bluetooth devices
directly. The disadvantage of this method is that this WSn does not support multi-hop
networking, which means that the WSN is limited by the range of the base station’s
Bluetooth. In order to achieve occupancy sensing, Passive InfraRed (PIR) Sensors have been
attached to the Arduino boards and the boards were programmed in such a way that would
transmit every time the PIR sensor detected activity and continuous states of non activity.
Data fusion for all the devices took place at a centralised MySQL database server – into
which each base station push sensor data – in order to provide a pseudo-synchronous view of
25
26
27
Industrial, Scientific, and Medical
Institute of Electronic and Electrical Engineers
Analogue to Digital Converter
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Technologies for Intelligent Building Services
the WSNs. To achieve the link between the base stations and the centralised server, bespoke
software was developed to forward data to the database. Perl and Python programs were used
to read directly from serial ports, and to decipher and convert the packets received from the
base stations of the WSNs. The converted data are then inserted into the MySQL database.
3.2 Visualisation tool for sensor data
As part of the architecture of the CMIPS building assessment tool, there’s a need to visualise
the computed assessment indices. But initially for this trial, we needed to display the sensor
data collected by the various WSNs detailed in the previous section. To this end, CMIPS
explored several options, looking at bespoke tools, with the resulting design as explained
below.
A prototype of the CMIPS visualisation tool (or user interface) was implemented using Adobe
Flex, which is a tool that allows the creation of rich Internet applications compatible with
most browsers and operating systems. Using Adobe Flex, a web-based interactive prototype
was created and tested out during the field trial. Fig.3 is a screenshot of the user interface as
displayed in a popular web browser. During the trial the interface was accessible through the
Internet, via an Arup hosted server.
Fig 3. Screenshot of user interface of visualisation tool displaying the collected environmental sensor data.
The user interface has 3 major sections: the browser/selection section, the thumbnails section,
and the focal section. The browser/selection section is located on the left pane of the page. A
user is able to, in effect, parameterise a query to the MySQL database (that logs all the sensor
data returned from the sensor networks). The available parameters are:
• Location: User selects an area of the building, e.g. the Atrium or a larger area (the Ground
Floor).
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• Sensor: User selects a sensor platform, e.g. Crossbow’s MTS400, and also a specific
sensor type (if available for that platform), e.g. temperature.
•
Period: User selects period of time (in standard date format), e.g. 17/06/07 to 23/06/07.
The MySQL database is queried and the returned sensor data is plotted and displayed in the
thumbnails section. In Fig. 3, each chart in the thumbnails section (the top right panel)
represents the temperature readings from the Crossbow MTS400 sensors from a specific
location.
The bottom right panel in Fig. 3 is the focal section – this is where the user is able to select a
particular chart from the thumbnails section, and have it displayed in a larger format. This
zoom-in feature makes it easier to browse through the thumbnail in greater detail.
3.3
Results and discussions
During the field trial, a lot of sensor data were recorded from the variety of sources – wireless
sensor platforms, BMS sensors, and Internet based proxies (e.g. weather.com for macro
physical data). A selection of charts is examined briefly in this section to demonstrate the
usefulness of the CMIPS tools.
The variety of sensor platforms available can lead to inconsistent sensor data obtained from
essentially co-located sensor platforms. Fig. 4 shows the temperature measured in the Atrium
(see Fig. 2 for location of this space) area over the same week by two sensor platforms.
Fig. 4.1. The temperature measured in the Atrium by a Crossbow MTS400 sensor. Y-axis is in °Celsius.
Fig. 4.2. The temperature measured in the Atrium by a BMS sensor. Y-axis is in °Celsius.
The above figures are selected charts produced by the field trial visualisation tool. The
measurements are taken over a period of 1 week (17/06/07 – 23/06/07).
Fig. 4.1 and Fig. 4.2 shows that the temperature in the Atrium remaining largely in the
‘comfortable zone’, i.e. 21 - 24°C, as measured by both the Crossbow MTS400 sensor (Fig.
4.1) and the BMS sensor (Fig. 4.2). This serves as a confirmation that the Atrium is largely
maintained at the comfortable temperature over the week. However, Fig. 4.1 shows that
during certain times of each day the temperature exceeds 24°C by a significant margin, which
is not reflected on the BMS sensor. There can be several reasons for this, such as incorrectly
calibrated sensors, or non-optimum placement of sensors. An investigation by the building
manager can pinpoint the cause of this inconsistency. This demonstrates the usefulness of
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having geographically denser sensors, which leads to a better visibility of the variation in the
environment.
The figures below demonstrate the possibility of deriving new insight from data generated by
different sensors. Fig. 5.2 shows the periods when the Meeting Space Insight (see Fig. 2 for
location of this space) was occupied, sensed via the PIR-equipped ArduinoBT sensor
platform. Fig. 5.1 recorded the temperature variation in the same space over the same 1-week,
sensed via the Crossbow MTS400 sensor.
Fig. 5.1. The temperature measured in the Meeting Space
Insight by the Crossbow MTS400 sensors. Y-axis is in
°Celsius.
Fig. 5.2. The presence of people recorded in the Meeting
Space Insight. The readings (Y-axis) are binary.
The above figures are select thumbnail charts produced by the CMIPS visualisation tool. The
measurements are taken over a period of 1 week (17/06/07 – 23/06/07).
Fig. 5.2 indicates that the space is infrequently occupied, at least in the week that the
measurements were taken. Despite this, Figure 5.1 indicates that the space was kept at a
comfortable temperature throughout. Granted that the space is not an enclosed area, therefore
the climate cannot be locally controlled, but if the pattern is repeated over several other
spaces, then there is scope for better planning. A suggestion would be that the space be
enclosed so that there is better local climate control, which can potentially save energy in the
heating/cooling of the space. This granularity of sensing was previously not available via the
BMS sensors.
3.4 Observations and lessons learnt
Earlier in Section 3, the objectives of the field trial were specified. This section elaborates on
the observations made whilst attempting to achieve these objectives.
Objective 1: Test environmental sensors and their communication platform
I. The wireless sensors, whilst communicating wirelessly, are not completely untethered. For
example, the Irisys people counter requires a relatively large and stable power supply,
which means that it has to be powered by mains. This can be a problem if there’s no
nearby mains sockets and therefore restricts the ease of deployment of this sensor.
II. Power consumption of the sensor platforms is always a concern. For example, the
Crossbow sensor platform’s default sensor program (as used in the trial) samples every
on-board sensor and reports the data periodically. This can drain its batteries very quickly
if it reports too frequently, due to radio transmission costs. During the trial, it is found that
restricting the reporting period to above 8 minutes will allow the sensor platform to
survive over 1 month. However, it must be noted that the CMIPS sensing middleware
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solution aims to extend battery life by employing several strategies, such as sampling
sensors only if requested by WSN clients.
III. The pattern of the sensor data being reported can also affect the battery life of the sensor
platform. For example, the PIR sensors report binary data – which requires only 1 bit to
represent its output, but can reduce battery life very quickly from radio transmissions as
they can produce very dense data output when sensing a busy space. A different reporting
strategy has to be developed for this type of sensor.
IV. The wireless communications for each of the sensor platform was fairly reliable, with
relatively few outages.
Objective 2: Identify potential issues when placing the bespoke sensors around the test site
I. One of the issues identified was to make sure that the sensors were placed strategically,
e.g. not covered or too near windows. The sensors also had to be clearly marked as
occupants occasionally disturb them, often unintentionally, which can affect their
reporting. Sturdy plastic casings are being built to protect the sensors for the field
deployment planned in the near future.
Objective 3: Gather real-time sensor data and test a user-friendly visualisation tool to present
the data to users
I. The prototype visualisation tool was found to be sufficient for visualising the sensor data
that was collected over the field trial. The tool can be easily extended to visualise the
output of the assessment indices, which achieves one of the purpose of the visualisation
tool.
II. The gathered sensor data is also useful for verifying the algorithms used in the prototype
assessment tool. The assessment tool is still ongoing development.
4. Summary
The CMIPS field trial is a precursor to the field formal deployment trial scheduled for early
2008. The field trial was an opportunity to spot any potential problems that has to be
addressed if the formal field deployment is to be as trouble free as possible. Some of the
observations are as follows:
1. The developed prototype visualisation user interface was a useful step in verifying the
design of the visualisation tool. As the tool as was put through its paces during the field trial,
by using it to plot collected sensor data, it was demonstrated to be of a acceptable design. The
prototype is to be extended to visualise assessment indices in future deployment.
2. Power consumption on battery operated sensor platforms must be reduced – by employing
less frequent reporting periods, and improving reporting strategy on frequent events sensors.
3. Sensors should be protected from occupants – by marking them clearly, placing them
strategically, and building protective boxes.
4. Sensed data from different sensor platforms can be inconsistent, e.g. BMS data vs.
Crossbow sensor data – this is found to be not too significant, but should be addressed
eventually to ensure accuracy of sensor data.
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Overall, it was found that the field trial has been successful and has provided useful input to
the ongoing work in CMIPS project over the second half of 2007.
Acknowledgment
This work was undertaken in the CMIPS project, which is partially funded by the by the
Technology Strategy Board, UK. The authors would also like to thank their TRT (UK) and
CMIPS colleagues for the fruitful discussions and comments made in the development of
work presented in this article.
References
1. Gassmann, O. and Meixner, H., Sensors in intelligent buildings: Overview and trends, in
Gassmann and Meixner (editors) Sensors in Intelligent Buildings, volume 2, 3-25, 2004.
2. Clements-Croome, D.J., Intelligent buildings: design, management and operation. Thomas
Telford, London, 2004.
3. SCC, Shanghai Intelligent Building Appraisal Specification, Shanghai Construction
Council (SCC), Shanghai, China, 2002.
4. CABA, Building IQ Rating Criteria. Task Force 1 – Intelligent Building Ranking System,
Continental Automated Building Ranking System, Continental Automated Building
Association (CABA), Ottawa, Canada, 2004.
5. AIIB, IB Index, third ed., Asian Institute of Intelligent Buildings (AIIB), Hong Kong,
2005.
6. Bssi, R., MATOOL: A matrix tool for assessing the performance of intelligent buildings,
Proceedings of the BRE Seminar on Intelligent Buildings, Building Research
Establishment Ltd., UK, 2005.
7. DQI, The catalyst for providing better buildings, http://www.dqi.org.uk/DQI/default.htm,
The Design Quality Indicator (DQI) website, retrieved in Sep. 2006.
9. CIBSE, Comfort, The Chartered Institution of Building Services Engineers, The CIBSE
Knowledge Series KS6, 2006.
10. Croome, D.J., Building Services Engineering - the Invisible Architecture, Building
Service Engineers Research Technology, 11(1) 27-31, 1990.
11. Wargocki, P., Seppanen, O., Andersson, J., Boerstra, A., Clement-Croome, D.J., Fitzner,
K., and Hanssen, S.O., Indoor Climate and Productivity in Offices How to Integrate
Productivity in Life-Cycle Cost Analysis of Building Services, Federation of European
Heating and Air-conditioning Associations Guide Book No.6, 2006.
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Integrated Overall Building Services Systems Architecture
Veijo Lappalainen1, and Kalevi Piira1
1 VTT Technical Research Center of Finland
{Veijo.Lappalainen, Kalevi.Piira}@vtt.fi
Abstract
Paper describes the overall Building Services systems architecture developed in I3CON project targeted to serve as a
reference in the development of Industrial, Integrated, Intelligent building Construction. As a starting point the system
environment is analyzed and requirements from related systems for the architecture are identified and discussed. The overall
Building Services system covers various mechanical and electrical building service systems taking care of production and
distribution of technical building services into the spaces as well as the operations coordination through automatic and
manual controls in order to achieve the indoor air quality and other targets. Achieved space conditions as well as available
utilities and services are important performance factors, which influence on the productivity of the primary usages of the
space.
Keywords
building services, architecture, intelligent, integrated
1
Introduction
Building Services (BS) systems are a fundamental part of Industrial, Integrated, Intelligent
construction. The overall BS system is composed of different BS systems, which produce and
distribute the technical building services into the spaces where they are consumed in order to
create safe & secure, productive and effective i.e. high performance space conditions
throughout the life cycle of building. The development of compatible subsystems, modules
and components requires the availability of the reference architecture for the overall BS
system. In this paper the preliminary results of I3CON project in the subject area will be
introduced [1].
A few references to related research and development activities in the BS domain can be
observed. Modeling of the structures and properties of BS systems has been carried out for
years by IAI (International Alliance for Interoperability) [2] targeting to IFC (Industry
Foundation Classes) product models. Presently the society in question is also known by name
buildingSmart. Regarding Building Automation and Control Systems (BACS) hardware and
functions have been specified in the standards [3], [4] developed in co-operation by ISO/TC
205 WG3 Building Controls Design and CEN/TC 247 Building Automation, Controls and
Building Management. Activities within Continental Automated Buildings Association
(CABA) related to intelligent buildings are also important [5]. Regarding national activities,
e.g. Finnish Building Services Technology Programme CUBE has been remarkable [6].
Regarding general control systems architectures Purdue Reference Model [7] can be referred.
Regarding overall BS systems architectures the authors are not aware any related reference.
The structure of the paper is as follows. The first chapter introduces the scope of the BS
architecture and the next one the systems environment of BS system. The following overall
BS architecture chapters cover the descriptions of primary BS systems, Building Automation
and Control Systems and the space module. The next chapters describe the ideas of overall
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control concept and primary BS systems concepts. Finally the main research results are
concluded.
2
Scope and approach
The BS systems architecture is primarily concerned with the following items: the composition
of the system from subsystems, internal interfaces of the system among its subsystems, and
the interface between the system and its external environment. Figure 10 illustrates this
approach. Requirements level shows the overall BS system in its systems environment.
Architecture level shows the division of the overall system into conceptual subsystems. On
systems concept level concrete BS subsystems are specified and their alternative systems
concepts defined. The lowest level shows the implementation of BS concepts from
installation modules and components.
One of the basic requirements for the overall BS system architecture in I3CON project has
been that is must support industrialized, integrated, intelligent construction. An important
requirement is that the architecture should support also the Operations and Maintenance stage
of the building life cycle in addition to the preceding stages (programming, conception,
design, construction and commissioning). A specific requirement is that the architecture
should cover various building types. The targeted building types are offices and other
commercial buildings as well as residential buildings.
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Figure 10. Scope of overall BS system architecture. WPx and Tx.x refer to related I3CON Work Packages and
Tasks of I3CON project
3
Systems environment
The systems environment of the overall BS system is presented in Figure 2. The overall BS
system includes the different BS systems, which produce and distribute the technical building
services through the room units into the spaces and take care of their usage through automatic
and manual controls to achieve the targeted Indoor Air Quality (IAQ) and other targets. The
achieved space conditions and the available utilities and services are factors, which have
influence on the productivity of the primary usage of the space.
For the sake of simplicity, the term space covers all spatial objects like space/room, technical
space, space group, building, and real estate.
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Figure 11. Systems Environment of Building Services
In the following the external systems shown in Figure 2 will be briefly described.
External Utility Services deliver various regional services like energy, water, data
transmission, etc. to their customer buildings. Buildings are connected to regional utility
distribution networks (electricity, water and sewage, gas, district heating and
telecommunications) on building level in centres in which the utility consumptions are
measured for billing.
The feasibility of a BS system concept, especially HVAC, depends on Spatial and Structural
Systems solutions. For example, the system concepts for low energy buildings can be based on
low temperature heating and cooling systems. These set requirements for the thermal
insulation of walls and windows which have to be met in order to be able to realise low
energy building.
Real Estate Business concerns with the real estate ownership and real estate being an
investment. Depending on the business type and strategy the need for the connection with the
building can vary. In principle, the information needed is the business related information
such as cost, income and profit. There could also be various performance metrics, which
indicate, what the real development behind the profit figures is. These figures could be
measured automatically and real time by a BS system (BACS).
External services provided by service operators and enabled by new information and
communication technologies will become more common in the future. Service work is carried
out using service applications, which are remotely connected to the building. These services
are for example remote alarm monitoring, remote operation, remote diagnostic, facilities
management, preventive and proactive maintenance, Internet-based information access,
entertainment services etc. A requirement for the building is the connectivity of BS systems
and the availability of the necessary building related spatial, structural, usage etc. information.
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Building management, operations and maintenance activities are responsible for optimal
operations of building related to different targets concerning indoor conditions and other
performance factors. The methods of continuous commissioning with appropriate
performance metrics are applicable here. In this context a new paradigm is Real Time
Building meaning real time accessibility to all building information covering Building
Management Systems (BMS), Building Information Model (BIM) and administrative.
Regarding the term Building Management, see [8].
Building Information Management covers the building information systems infrastructure in
order to collect, transmit, store and make accessible different types of building information for
service and end user applications.
Regarding Enterprise Systems a present trend is the shift towards real time enterprise
solutions. Its target is basically to make the enterprise processes more sensitive and reactive to
the actual state within the enterprise. The objectives are more effective use of resources,
quicker decision making cycles, shorter delays etc. This is enabled by real-time integration of
different enterprise information systems such as HR 28, R&D2, CRM3, Supply Chain, Finance
and Facilities. Buildings and spaces are a kind of facilities for enterprises. The performance of
the building influences also on personnel’s productivity. The extensive overall information
space of the enterprise should cover thus also some building information.
Building services are delivered to Spaces where they will be consumed in order to generate
safe & secure, productive and effective i.e. high performance space conditions. The term user
covers all different user groups: employees, occupants, visitors, customers, service persons,
and unauthorized visitors. Spaces are a significant resource and competitive factor for the
primary usage activities. The performance of spaces has various effects on the operation,
productivity and well-being of individuals and organizations working in them.
4
Overall BS systems architecture
The overall BS system can be very complex and include several different types of BS
subsystems. Feasible BS system concepts depend also on building type and structural
solutions. This implies that overall BS architecture has to be presented on a high level of
abstraction based on generic BS systems. The overall BS systems architecture has been shown
in Figure 3. Colored lines describe the service flows from external sources to consumption.
The main parts of the overall system are as follows:
- Primary BS subsystems each of which delivers a specific service to spaces to be consumed
by actors, which can be also other BS subsystems.
- BACS which takes care of operations monitoring and control as well as functional
integration of BS and space systems. BACS also takes care of data acquisition and
communication with higher level building information systems.
- Space system is the consumption place of different building services, which enter to and
mix in the space influencing space conditions. To meet optimally the performance
requirements the usages of the services have to be coordinated by space automation.
28
HR = Human Resources; 2 Research & Development; 3 CRM = Customer Relationship Management
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Figure 12. Overall BS systems architecture.
In the following these parts will be described in more detail.
4.1 Primary Building Services subsystems
Technical building services can be classified into mechanical and electrical building services.
Heating, cooling, ventilation, air-conditioning and smoke control are examples for mechanical
building services. The term electrical building services covers power distribution, lighting,
access control, fire detection and alarming, intruder detection and alarming as well as BACS.
A generic model of a BS system is its composition of Generation, Center, Transfer and Space
(alternatively Room) modules as shown in Figure 13. These four modules are generally
adequate to allow modeling of all BS systems. A single BS system does not however have to
be composed of all these modules.
Generation module is primarily related to energy systems, which can have building level
energy generation units, such as solar heating and ground or air heat pumps. Lighting system
is an example of a BS system having less than three modules. It takes electricity from space
level power distribution system and has only space module.
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Figure 13. General module structure of a BS System
Center module can include the connection to the external supply systems (regional grid and
water & sewage networks), possible BS production process as well as internal branching to
building level BS distribution systems. Utility consumptions are usually measured for billing
at the center modules. The Air Handling Unit (AHU), the electric main board and the district
heating’s outstation are examples of center modules.
The transfer modules are building level distribution networks/subsystems of the BS systems.
They are BS system specific: cabling system for electrical distribution network, ventilation
ducts for air distribution and retrieval, plumbing system for drinking water distribution, etc.
They can be further divided into vertical and horizontal transfer modules.
BS modules can be equipped with embedded automation and intelligence including local user
interface for service personnel. This can be for example simple push buttons and meters or
computer based touch screens.
The scopes of a BS system and BACS regarding automation functions and hardware are not
always trivial. Basically a BS system covers all its internal automation that is not integrated
with other BS systems. A BS system can utilize BACS infrastructure as a resource, e.g.
BACS control network as a communication channel for internal integration of BS system.
The modular structure – center, transfer, and space – is applicable also on the space level i.e.
flat, office, etc. Then certain BS needed in a space is first delivered to the center of that space.
There they are further connected to the distribution network of that space. The space center
can also be equipped with consumption counters for different building services (e.g.,
electricity, heating and cooling energy, water and gas).
4.2 Building automation and controls system (BACS)
The role of BACS differs from other BS systems in that BACS does not deliver any direct
service to the space like the other BS systems. The main task of BACS is to take care of
proper and integrated operation of other BS systems. At the same time BACS acts also as a
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building management tool and real-time building information system. BACS infrastructure is
also a resource for implementation of automation functions for BS systems.
Not all BS systems need however BACS services, i.e. monitoring, control etc. Some of them
can work in a stand-alone fashion without any need for integration to BACS services.
The overall BACS can compose of more than one system. For example in some safety critical
applications special purpose systems are commonly used.
BACS functions can be classified into four types [3]: I/O-functions, processing functions,
management functions and operator functions. Other basic resources of BACS are control
network protocols and external interfaces. For BACS protocols basic architectural elements
are object types and services. For external interface the basic alternatives are BACS protocol
itself, Web Services or Gateway.
4.3 Space module
The space module in Figure 12 includes following units.
- Space module of BS system (BSS) which is connected to the space controller (BACS) if
the specific BS influences on space conditions or if the information is needed for reporting.
- Space device, which is a specific device influencing space conditions or enabling some
additional service, such as air-to-air heat pump. The space device can be connected for
integration or data acquisition for example through sensor network.
- Space controller (BACS) takes care of integrated control of the usage of different building
services. Space controller is connected to BACS network, which connects the space module
to higher-level control loops and building management as well. It also connects BS specific
space units to overall horizontal control of the corresponding building service.
Possible additional elements of the space module can be also the following.
- Sensors and actuators as generic I/O functions in space, for example temperature and IAQ
sensors and contact output
- Ambient user interface, which is an automatically generated, personalized, location-based
user interface. It can use for example sensor networks for the discovery of the identity of a
person and its location and mobile access in connection to BACS and BIM (Building
Information Model), from where the structural and real-time information for space user
interface can be accessed.
5
Overall control concept
In Figure 6 a concept for overall control system of BS production, delivery and usage process
is presented. The structure of the control system strictly follows the proposed hierarchical
structure from lowest level controls up to top-level coordination.
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Figure 6: Concept of overall control system of BS operations.
All modules (center, transfer, space) have similar process-control couple structure. The
contents of the process part correspond to the module in question. For Example, for space
modules the control block is the same as space controller (BACS) in Figure 3.
The next higher-level control of the space control is that of the office level. That level
coordinates the conditions and performances of the spaces belonging to that office. It also
takes care of monitoring and control of the building services at office not at space level.
On BS systems side the lowest control level is the module control level. Above that there is
the total internal (horizontal) control of each BS system.
6
Building services systems and their concepts
Technical building services systems and their connections to external utility systems such as
community’s water system and power distribution network are shown in Figure 7.
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Figure 7. Technical Building Services Systems and connections to external systems
Figure 7 shows the diversity of technical building services systems. Most of the systems are
more or less separated. They are typically used for special purposes and they can be based on
totally different kind of technologies. For example, the technology needed in access control
systems and ventilation systems have very little in common.
Another important aspect is that most of these building level systems are a part of regional
utility services systems representing generally different kind of technologies. For example, the
technology for connecting the heating system with the district heating network has very little
in common with the technology for connecting building information systems with
telecommunication networks.
6
Conclusions
In this paper a novel overall BS systems architecture has been presented. The architecture is
based on a generic systems approach and covers different building services and their usage in
spatial systems. The methodology also introduces an approach how the generic BS systems
can be refined into specific BS concepts.
The overall BS systems architecture presented is preliminary and will be further developed
during the course of I3CON project.
The main research results described in this paper are as follows:
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- Systems approach method for specifying the overall BS systems architecture, the modules
and subsystems/components, and description of the external interfaces to the BS systems.
- Novel overall BS systems architecture including system structures and connections.
- Novel overall control concept introducing the functional structure of overall control system
for the integrated production of building services and their usage in spaces.
Topics of overall BS architecture that need to be elaborated in future work are e.g.
- More extensive analysis of the spatial system.
- More extensive and detailed description of BS systems concepts.
- More detailed analysis of overall operations & maintenance management.
References
1. Preliminary Overall Building Service Architecture. I3CON Deliverable 3.1-1 (2007)
(confidential)
2. http://www.iai-international.org
3. EN ISO 16484-2 Building automation and control systems (BACS) — Part 2: Hardware
(ISO 16484-2:2005)
4. EN ISO 16484-3 Building automation and control systems (BACS) — Part 3: Functions
(ISO 16484-3:2005)
5. http://www.caba.org/index.html
6. CUBE - Building Services Technology Programme 2002-2006, Final Report. Tekes
Technology Programme Report 19/2006.
7. ANSI/ISA-95.00.01-2000: Enterprise-Control System Integration Part 1: Models and
Terminology
8. Building management - Terminology and scope of services, CEN/TS 15379:2006
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Integrated Building Information Service through Building
Services Gateway
Kalevi Piira1, and Veijo Lappalainen1
1 VTT Technical Research Center of Finland
{Kalevi.Piira, Veijo.Lappalainen}@vtt.fi
Abstract
Paper describes the architecture and the main principles of the Building Service Gateway (BSG) developed in I3CON project.
BSG will enable easy and standard based access to different kind of real-time and static building information. It will make
possible to develop applications supporting efficient, economical, high performance, productive buildings and related new
life cycle services.
Keywords
integration, building service gateway, building information system, building information model, building
automation and control system, building management system, building services
1
Introduction
The operation and maintenance of buildings have become dependent on building automation
and control system (BACS), building technical systems (HVAC control, electricity and
lighting control, burglar alarm, access control, CCTV), technical building management
systems (energy management, FM, BIM) and financial - administrative systems (accounting,
personnel administration, renting, space management). In addition, information solutions
which integrate building systems with enterprise systems are becoming more and more
important.
These existing building information systems and related standards are typically fragmented
and isolated from each other forming “automation islands”, which do not communicate
together. A consequence of this can be that the different systems contain overlapping
information, which creates a risk for data integrity. Also because of the lacking
communication between different systems, it is common that the information for integrative
applications must be collected up manually from different systems and reports.
An important challenge of today is to enable the utilisation of the information already existing
in different applications and systems. New information technologies and standards like
Internet and Web, building control networks, data communication protocols, wireless sensor
networks, product data technologies etc. enable the development of the integrated, intelligent
real-time buildings and related new business models. Related to this the basic idea in I3CON
is to integrate BACS and BIM information through building services gateway (BSG) to
deliver high-value information services for reporting of building lifecycle and energy
performance metrics.
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2
I3CON Information System Architecture
The main objective of the I3CON information system is to enable easy access for users and
applications to all building information including real-time building automation and sensor
network information as well as FM and service data base information.
The I3CON information system architecture is based on Service Oriented Architecture
(SOA), a generally used enterprise level integration approach today. In fact SOA approach
has been adapted also in the main standards (BACnet Web services [1] and oBIX [2]) for
interfacing building automation systems with higher level building management and
enterprise systems. Well-defined services enable different applications to utilize the
information provided by different systems without knowing details of these systems and
technologies behind the service interface. The general structure of I3CON information
systems architecture is shown in Fig. 1.
Fig. 14. Building information systems architecture. [3]
Typical examples of BACS related information are
-
real time values (temperatures, energy consumption, etc.)
-
status information (on, off)
-
historical data
-
controls
-
alarms
Typical examples of BIM related information are
-
site, building, structures, spaces
-
building elements (walls, doors, roofs, stairs, openings, …)
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-
relations between building elements
-
HVAC (fans, heat exchangers, valves, etc.), control (sensors, controllers, actuators,
meters, etc.), electrical, fire protection and sanitary elements etc.
-
systems (piping, ducting etc.)
-
network topology (element connectivity), service history etc.
-
actors, work plans, costing, time series, constrains (requirements, rules)
-
geometry, drafting
There have been several activities that have addressed BIM including BS domain projects
within International Alliance for Interoperability (IAI) [4] and BACS related standardization
activities within ISO/TC 205 WG3 (TC Building Environment Design, WG Building Controls
Design) and CEN/TC 247 (Building Automation, Controls and Building Management). There
have also been activities related to home automation like ISO/IEC JTC 25 WG 1: Home
Electronic Systems (HES) and CENELEC/TC 205: Home and Building Electronic Systems
(HBES) [5].
3
Building Information Gateway
One of the key components in I3CON information system architecture is BSG, which
basically combines the information about same or related objects which is distributed in
different systems with their specific data models. Regarding ambient building management
and enterprise applications the main interest is concerned with the integration of BACS
including security & safety systems and BIM. BSG is regarded as a potential concept for
future buildings to enable, integrate, and manage most part of building related information
and to deliver high-value driven business concepts based building life cycle services
supporting efficient, economical, high performance, productive buildings.
The main role of the BSG is to facilitate quick and secure data transfer between SOA
information services and related applications and standard based BIM and BACS. BSG will
combine the needed information from/to BIM and BACS using Web services interfaces so
that the integration of BIM and BACS data seems seamless to the end user. The preliminary
idea for BSG’s external interfaces is shown in Fig. 2.
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End user application
Other service
<<uses>>
Building
information
services
<<uses>>
BSG service
<<uses>>
<<uses>>
<<uses>>
BSG
service
BACS service
BIM service
Fig. 2. General use case model of BSG.
The typical integrated BSG services needs information from location (user place, room, zone,
building), location related components (sensors, devices, systems), components service
history (when, what, who), components historical data (for example temperature values from
1.2.2008 to 15.2.2008), components real time information (temperatures and other indoor air
quality related measurements, energy and water consumptions, device status (on/off), alarms
etc.) and system related information (system, sub system, device, data point).
3.1 BSG – General Requirements [3]
The main requirement for BSG is an open service interface specification for data access
(monitor, control, use, manage) by SOA applications and based on standard BIM (IFC) and
BACS (BACnet, etc.) protocols. At the first stage BSG will be support mainly building life
cycle and FM services like space related services, building lifecycle performance metrics
reporting, new value driven services and for advanced use of simulation during the building's
lifecycles.
Other requirements for BSG, which are more important during the productization stage, are
related to performance (reasonable response times for end users), dependibility (data integrity,
able to recover from failure, no additional damages in the case of failure), security
(identification and authentication, roles based security polices), usability (simple, easy to
remember and uniform way to develop end-user application and configure and manage
gateway, well-defined error messages), supportability (expandable, open and easy to deploy
and use for application developers, transparent for end users) and implementation
requirements.
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3.2 BSG – Implementation Requirements
The main implementation requirement for BSG is the support BACS and BIM Web services.
The utilization of common SOA related technologies especially Web services is also required.
Main contribution is focused to the addition of integrated Web services to standard based
building automation web service technologies like BACnet Web services (Table 1), open
Building Information Exchange, oBIX, OPC UA and BIM web service technologies like IFC
- SABLE & SABLE Web services [6].
Table 1. BACnet Web services (Addendum c to ANSI/ASHRAE 135-2004).
BACnet web service (addendum c to ANSI/ASHRAE 135-2004)
CString getValue(CString options, CString path)
CString[] getValues(CString options, CString paths[])
CString[] getRelativeValues(CString options, CString basePath, CString paths[])
CString[] getArray(CString options, CString path)
CString[] getArrayRange(CString options, CString path, unsigned index, unsigned count)
CString getArraySize(CString options, CString path)
CString setValue(CString options, CString path, CString Value)
CString[] setValues(CString options, CString paths[], CString values[])
CString[] getHistoryPeriodic (CString options, CString path, CDateTime start,
double
interval,
unsigned
count,
CString
resampleMethod)
CString getDefaultLocale (CString options)
CString[] getSupportedLocales (CString options)
Other implementation requirements for BSG are as follows. It must be scalable, IP and Web
services based and accessible from a wide range of different kind of clients and terminals like
personal computer, PDA and mobile phone (Fig. 3). In addition, it must use of open BIM &
BACS standard interfaces and protocols wherever possible.
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<applications for building life cycle>
Low range communication
networks
Mobile
Mobilenetworks
networks
IP
IPnetwork
network
Building Automation and Control Systems
BAS
BAS
(BACS)
BSG
Building Service Gateway
BIM
Fig. 3. Physical connections of BSG.
3.3 BIM and BACS Data Model Mapping
As mentioned earlier there are official and de facto standards for BACS and BIM data model
but there exists no standard for the mapping between the objects and their properties of BACS
and BIM. This is one of the key problems in BSG kind of applications because BIM model
does not know the BACS object IDs and BACS data model is different than related BIM data
models. The minimum level mapping means that there is a mapping table of object IDs which
links the equivalent BIM and BACS objects e.g. devices (sensors, fans, air handling units,
etc.).
BSG related BIM and BACS mapping can be based on IFC model extension called IfcProxy.
It can be expected that initiatives for standardization of BIM and BACS mappings will be
promoted in future IFC standardization projects.
3.4 BSG Web Services
Alternative approaches for structuring and definition of BSG Web services have studied in
I3CON. In one of the potential approaches BSG has two types of Web services, low level and
high level Web services. Low level Web services are for general use. Typical low level
services are getInstanceByID and getInstancesByType (Table 2). For example
getInstanceByID service returns BIM or BACS model in xml format based on BIM or BACS
data model. BSG does not have to know anything about the used data model. An another
example, getInstancesByType service returns a list of BIM or BACS objects which are given
type in xml format based on BIM or BACS data model.
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Table 2. Example of BSG low level services.
BSG basic services
Description
CString getInstanceByID(CString
instanceID, CString scope, CString[]
moreInfo, revision)
Description:
•
this method returns the instance by given BIM or BACS ID
Parameters:
•
instanceID is instance ID in BIM or BACS system
•
scope is BIM or BACS
• moreInfo is XML string including possible option BIM WS
parameter strings, used BACS standard name etc.
•
revision is instance BIM or BACS revision number (optional)
Return values:
•
BIM or BACS instance (ifcXML or BACS xml string)
Error messages:
CString[]
getInstancesByType(CString
instanceType, CString scope)
Description:
• this method returns all the instances by given BIM or BACS type
(example ifcFan)
Parameters:
•
instanceType is instance type in BIM or BACS data model
•
scope is BIM, BACS or ALL
Return values:
•
List of BIM or BACS instances (ifcXML and/or BACS xml string)
Error messages:
High level Web services are for special use and they are based on low level services. The idea
is to implement some most needed client side algorithms into the BSG. For example the
service getDevicesByLocation returns a list of device objects in BIM or BACS data model
based xml format which are in given location (typically space). In another words, the high
level services use low level BSG Web services which use BIM and BACS Web services.
4
Conclusions
In this paper a preliminary BSG concept has been introduced. Final definitions and further
development will be done during the I3CON project. The main results covered in this paper
are I3CON information systems architecture, BSG overview, BIM and BACS integration
overview and basics of BSG Web services.
The potential impacts of BSG are based on its enabling, real time, integrative building
information services for operations & maintenance and enterprise level applications for
efficiency, economy and safety & security of building as well as productivity of occupants’
activities. Quantitative figures on saving potentials are difficult to estimate because the effects
are indirect. However, some comparable figures can be found from the reference [7] in
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which the efficiency losses in the U.S. capital facilities industry resulting from inadequate
interoperability have been identified and estimated.
Examples of these new services are building performance contracting (guaranteed
temperature, CO2 and illuminance levels etc.), ESCO (Energy Service Company) and other
energy management services as well as online commissioning and building predictive
maintenance service. The information services of BSG can also to be utilized in ambient
intelligence based applications developed for people inside the building.
A major challenge for BSG is its specification and implementation based on standard data
models without non-standard model extensions. Other challenges are related to the
performance of BIM side interface of BSG.
References
1. http://www.BACnet.org
2. http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=obix
3. Kätkä, A., Mitjonen, J., Piira, K., Lappalainen, V., Negrea, M., Badescu, M.: Building
Services Model. I3CON deliverable D6.1-1 (confidential)
4. http://www.iai-international.org
5. http://www.hes-standards.org
6. http://www.blis-project.org/~sable/
7. Gallaher, M. P., O’Connor A. C., Dettbarn Jr. J. L., Gilday L. T.: Cost Analysis of
Inadequate Interoperability in the U.S. Capital Facilities Industry. National Institute of
Standards and Technology (2004)
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Customer Satisfaction with Maintenance Contracts: Examination
of Key Performance Indicators Used to Measure Customer
Satisfaction with Mechanical & Electrical Maintenance Contracts
and the Level of Importance Placed on Them by the Customer
Joanna Harris
FM Engineering Centre, BSRIA,
Bracknell, Berkshire, RG12 7AH, United Kingdom
[email protected]
Abstract
This paper describes research results that measured customers’ satisfaction of Mechanical & Electrical (M&E) maintenance
contracts. The paper considers which of the Key Performance Indicators (KPIs) offered affected overall satisfaction as well
as the level of importance placed on them by the customer.
The key findings were two fundamental deliverables that the customers require as a matter of importance; response to
breakdowns and quality of planned maintenance. Three other KPIs highly rated in the 2007 survey were measurable
deliverables: statutory and legislative compliance; keeping within the budget; and contractor performance against service
level agreements.
It is concluded that the ‘management of the contract’ above all else affects customer satisfaction of M&E maintenance
contracts.
Analysis of the results puts emphasis on, communication, trust and honesty, having a positive
customer/contractor relationship, being proactive and showing initiative.
Keywords
maintenance contracts, customer satisfaction, performance measurement.
1
Introduction
Maintenance is an essential part of building ownership but managing an in-house maintenance
team is generally not part of the core business. Outsourcing maintenance has become
popular in the last decade as a business strategy to deliver cost reductions, reduced headcount,
focus on core business and increased competitive advantage.
The problem is that customers are not satisfied with the service they are getting, BSRIA
(2006)[1]. BSRIA Ltd has been collecting customers’ views on M&E maintenance
contractors for three years. The data is used to produce key performance indicators (KPIs)
for the industry to measure their contractors, and also for the contractors to compare their own
performance against a benchmark.
With facilities management policies set to meet the needs of each business the key drivers are
variable. As policies change so does the level of importance being placed on each of these
KPIs. The BSRIA KPIs were selected through collaboration with M&E contractors in 2003
and are the KPIs that contractors perceive customers are interested in measuring. This leads
to the assumption that if the contractors address all these areas they will have satisfied their
customers.
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This research challenges this assumption. The BSRIA historical data is examined along with
new data that ranks the importance for each of these KPIs. There is also investigation into
other more appropriate measures. For example, industry is driving Facilities Managers
(FMs) to show added value to the core business. Is this an appropriate measure for M&E
maintenance contractors? Should there be a KPI now measuring if the contractor is adding
value to the business or delivering over and above the customers’ expectations?
To be valuable to the customer, a service must make a difference to them and their business.
A focus on customer satisfaction means their needs have to be understood and acted upon.
Getting feedback on each deliverable through customer and contractor service review
meetings is crucial. Greater understanding of the needs of the customers shows where
contractors will need to focus their efforts.
There was very little literate found that looked into or attempted to address the needs of the
maintenance contractors’ customers. This lack of available data defined the aims of this
research to close the gap in the secondary data.
1.1
Aims and Objectives
The aim of this research was to measure customers’ satisfaction and determine which KPIs
used to measure M&E maintenance affected overall customer satisfaction as well as the level
of importance placed on them by the customer. The objectives were specifically to:
•
rank how important each KPI was to the customer and examine the levels of importance
placed on the KPIs from different sectors
•
determine which KPIs reflected the overall satisfaction of the customer
•
indicate how KPIs need be adapted to keep up with the changing needs of businesses.
2
Why maintain?
Thompson (1994)[2] gets to the point and suggests that some businesses have forgotten, in
their drive to cut costs, that maintenance of their buildings is an essential function for a
business. Maintenance directly effects operating costs and ensures good staff health and
morale, while in the long term keeping capital replacement costs under control. Thompson
(1994) [2] states, what every building owner/operator should know, is that poor or neglected
building and plant maintenance will result in escalating costs.
2.1
Outsourcing
Embleton and Wright (1998) [3] comment that in today’s environment, managers are searching
for any edge that can provide them with success and indicate that outsourcing is one approach
that can lead to greater competitiveness.
Francis (2003) [4] considers that contractors can bring vital fresh thinking to an organisation
and introduce savings and benefits including cultural change, controlled operating costs,
access to specialised resources and risk sharing, and enables better management.
2.2
Performance measurement
Varcoe (1993) [5] states, along with many others, that ‘what gets measured gets done’.
Murthy et al (2002) [6] reinforce this by suggesting that when maintenance is outsourced there
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is a temptation for the contractor not to carry out all the maintenance tasks properly and this
can have a long-term consequence on the core business.
Hayes et al (2000) [7] comment that one NHS trust, widely regarded as an exemplar of FM in
its sector put forward as a model in ministerial level discussions to abandon service level
agreements (SLAs). Year-on-year demonstration of improvement and customer satisfaction
was considered more important and the bureaucracy associated with the preparation of the
SLAs considered counter-productive and an unnecessary cost.
Allery (2004) [8] would disagree with this practice as he states that the key to successful
contracts is the clarity of the service requirements and service levels achieved. He validates
this by saying that it is the service levels that the client is ultimately paying for and without
clear deliverables there will be potential for differences in what is expected and what is
delivered.
2.3
Relationship
Prior and Nowak (2004) [9] concede that the biggest barrier to close relationships arises from
the mistrust that often exists between clients and contractors, stating that this comes from the
adversarial culture inherited from the construction industry, which creates doubt over probity,
quality and cost control. They point out that there is a need to develop a contractual
relationship that allows the benefits of partnering to be realised, focussing on co-operation
rather than conflict leads to a better working environment.
2.4
Identified influences to success or failure of outsourcing
Booty (2003) [10] provides an overview of outsourcing and considers one of the important
areas to ensure success is that continuous improvement is achieved. To clarify this statement
Booty (2003) [10] goes on to describe the need for the contractor to be proactive and for the
customer to ensure clear lines of communication are open.
Falconer (2006) [11] comments on a survey carried out by the National Outsourcing
Association in 2005 that lists the following for failure of contracts, hidden costs that reduced
the cost efficiency of projects, relationship breakdowns, failure to meet service levels and
customer’s lack of preparation and research. Falconer’s (2006) [11] article supports this last
point by providing a quote:
“organisations learn too late that managing external services requires vastly
different competencies than managing the same, internally provided services”.
Gonzalez et al (2005) [12] suggests that contractors need to understand the customer’s
objectives and understand that the customers do not want to be treated impersonally. This is
echoed by Hayward (2007) [13] when referring to customers of Total Facilities Management
(TFM) contracts. Carder (2007) [14] provides a list of factors that can cause outsourced FM
contracts to go wrong and comments that many of the underlying problems are caused by the
customers.
2.5
Customer satisfaction
Looking at the problems that occur between FMs and contractors Carder (2007) [14] suggests
that two people can interpret the same contract with differing expectations. It is these
differing expectations along with past experiences, internal customers and personal agendas
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that cause poor customer satisfaction. Carder (2007) [14] sums it up: “fantastic customer
service is not an option but imperative for the success of the FM industry”.
3 Methodology
Customer satisfaction primary data, from practicing FMs on recent M&E maintenance service
provision, was captured through the use of an on-line survey. The survey enhanced an
existing survey to ensure there was comparable data on customer satisfaction from previous
years allowing the changing views of customers to be analysed.
The on-line survey was modified from the 2005 and 2006 version used by BSRIA to include
further questions specifically to rate the importance of the KPIs and introduce new KPIs to
examine the changing needs of customers. The survey utilised multi-choice closed questions
as well as one open question to ensure that the respondents could provide further comments
on their experiences.
The population for this research were those people who outsourced mechanical and electrical
maintenance for non-domestic buildings. The quantitative approach allowed a wide range of
“representative” views to be captured. Further qualitative research was captured in the form
of three in-depth interviews. The interviews were carried out face-to-face and recorded
through the use of note taking. Using the survey and interview methods together enabled
triangulation and combined to complement each other. The two methods produced the same
insight into the needs of customers of M&E outsourced maintenance which as discussed in
the conclusions.
4 Findings and presentation of evidence
The following is a summary of the research findings. The three objectives were examined
using five tasks.
4.1
Task 1 Rank importance of the KPIs
The 2007 sample was asked to rank the five most important KPIs and the five least important
from the same list. Not all respondents completed this question, n=98 for question Q19
(most important) and n=90 for question Q20 (least important); the figures displayed in theses
tables are a percentage of the possible 101 responses for each KPI.
The results of the sample indicated that there are four fundamental deliverables that more that
50% of customers consider most important. Q1 quality of planned maintenance, Q2 response
to breakdowns, Q5 management of health and safety and Q14 communication, reporting,
sharing and use of helpdesk. The other eleven KPIs can be described as secondary
deliverables that are less important to the customers’ satisfaction level.
From the interviews undertaken as part of this research these finding were examined further.
Those in-house FM’s, with a background in building maintenance and engineering, retained
responsibility for areas such as Q4 energy management and Q5 health and safety. Therefore
this reduced the level of importance the customer placed on these elements.
Task 2 looks at two diverse sectors to determine if areas such as business drivers influence the
conclusions reached in Task 1.
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4.2
Task 2 Levels of importance placed on the KPIs from different sectors
The comparison of responses from two sectors, government departments (central and local)
and financial institutions, showed they were was not as diverse as expected. The central and
local government organisations placed more importance on issues such as Q5 managing
health and safety and Q6 managing, staff skills, competency and appearance than the financial
institutions.
The financial institutions placed more importance in Q4 maximising energy usage and Q15
managing the environmental impact of work but the fundamental deliverables, such as Q1
quality of planned maintenance, they both agreed were important.
Only one KPI Q15 management of environmental impact of the work was significantly
different between the two groups. Further research into the business drivers of these
organisations, such as employee retention, reputation, image, as well as the age of the
building would be required to examine why this difference exists.
This conclusion corroborates the findings of task 1 and it can be concluded that the sample
rated, quality of planned maintenance and response to breakdowns as the two must important
deliverables when they measure their level of satisfaction with their contractor.
4.3
Task 3 Determine which KPIs reflect the overall satisfaction of the customer
Historically BSRIA had combined three questions to determine overall customer satisfaction,
Q14 communication, sharing, reporting and use of helpdesk, Q8 contract management plan
and Q3 maintenance condition of the facility. A new question added in the 2007 survey
asked the respondent to rate their overall customer satisfaction.
To test this practice of averaging the correlation R² for each of the three aspects used by
BSRIA was calculated against the separate overall satisfaction question asked in the 2007
survey. The results showed that there is little correlation between each aspect. Further
investigation into the importance of these three aspects of service in relation to customer
satisfaction was asked in Q5 and Q6 in the survey in 2007 where the respondent was asked to
select five aspects of the service that were most and least important. When the results are
examined 46% of respondents rated contract management plan to be of least important.
Communication, reporting and use of helpdesk was rated by 53% of the respondents as being
of most important this is the 4th most important aspect in the list of 15 aspects being
measured.
Examination of the 2007 sample showed the correlation and importance placed on the three
aspects averaged by BSRIA to score overall customer satisfaction in previous years was small
and a large discrepancy between levels of importance. Therefore, the BSRIA practice of
averaging these three aspects to calculate overall satisfaction was not appropriate.
Further examination of the 2007 data was carried out to explore the relationship between
overall satisfaction and the other questions asking the respondent to rate the likelihood of
using the service provider again and how they would rate the contract for providing good
value.
Both correlation methods show strong linear correlation between all three aspects but the
correlation between overall satisfaction and providing good value is dominant. This
relationship was further examined with the production of a scatter plot diagram, the results
indicate the correlation R² = 0.8402 which illustrates the strength of the linear relationship.
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The results show that the relationship is strong; a value of 1 would be a perfect linear
relationship.
A further statistical test of the Pearson product moment correlation that
measures the degree of association between two variables indicates that R = 0.92 which again,
indicates a positive linear relationship between overall satisfaction and providing good value.
Therefore, for the two previous years where there is no single question asking the respondent
to measure overall satisfaction the use of the variable ‘proving good value’ is a good indicator
of overall satisfaction.
Therefore to determine which KPIs affect the overall satisfaction of the customer, correlation
of each KPI against Q16 providing good value was examined. A multivariate analysis was
used to construct a correlation matrix to examine the relationship between Q16 providing
good value and the 15 KPIs. The results were examined to identify whether any single KPI
affected overall satisfaction or if any of the variables had a negative relationship with overall
satisfaction. 32 cases with missing answers were discounted for this statistical test.
The Pearson product moment correlation coefficient uses the assumption of normal
distribution. It had been previously proved that the survey responses are all negatively
skewed. Therefore, both Pearson correlation and R² the non-parametric equivalent were
calculated for each KPI against Q16 providing good value. The correlation table, Table 1
below, provides an indication of the strength of the relationship between each KPI and Q16
providing good value but does not prove that one of the variables has caused the other.
The table is ordered with the KPI showing the largest linear correlation at the top and smallest
at the bottom. The strength of the relationship is in the range -1.00 to 1.00. The values in the
correlation table indicate the strength of the relationship between the variables. A correlation
of 0 indicates no relationship at all, a correlation of 1.00 indicates a perfect positive
correlation, and a value of –1.00 indicates a perfect negative correlation.
Coefficient of determination is also calculated; this demonstrates how much variance the two
variables share as a percentage, Pallant (2001) [15], Table 1. Coefficient of determination is
calculated by multiplying R² by R² and is shown as a percentage.
Correlation
Providing good value
Contract management plan
Maintenance condition of the building
Communication, reporting and use of helpdesk
Average for additional works
Quality of planned maintenance
Response to breakdowns
Managing documentation and record keeping
Managing staff skills and competency
Maximising energy efficiency
Managing environmental impact of work
Managing health and safety
Invoicing
Strength of relationship
Pearson R
R²
1
1
0.82
0.67
0.79
0.62
0.78
0.62
0.77
0.61
0.77
0.60
0.73
0.54
0.73
0.53
0.72
0.52
0.72
0.52
0.71
0.50
0.70
0.50
0.65
0.43
Coefficient of determination
Pearson R
R²
100%
100%
67.24%
44.89%
62.41%
38.44%
60.84%
38.44%
59.29%
37.21%
59.29%
36.00%
53.29%
29.16%
53.29%
28.09%
51.84%
27.04%
51.84%
27.04%
50.41%
25.00%
49.00%
25.00%
42.25%
18.49%
Table 6. Correlation of KPIs against providing good value n=262
Different statistics books suggest different interpretations; Pallant (2001) [15] refers to Cohen
and suggests the that those with an R value +/- 0.3 have a medium strengthen relationship
when looking at Pearson’s correlation results.
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Each of the KPIs showed a good positive linear relationship when compared to Cohen’s
interpretations but the five KPIs that explain the most variance in Q16 providing good value
and ultimately overall satisfaction in this sample are taken as those that show a coefficient of
determination above 34%, which Pallant (2001) [15] suggests is a respectable amount of
variance when compared with research conducted in the social sciences. These are Q8
contract management plan, Q3 maintenance condition of the building, Q14 communication
reporting and use of helpdesk, Q10 to Q13 average for additional works and Q1 quality of
planned maintenance.
With the methods available to the researcher, before a conclusion was made on which KPIs
affect Q16 providing good value and ultimately overall customer satisfaction, the importance
ratings assigned by the respondents in 2007 were examined again.
The importance rating given by the sample in the 2007 survey when combined with the
correlation of each KPI against providing good value results highlights an anomaly. 46% of
the customer’s rate Q8 contracts management plan as least important but the correlation
results show it to be responsible for the largest, 0.675 variance of Q16 providing good value.
The results from this sample demonstrate that it is an important KPI for the contractor to
address but indicates that the customer is not concerned with the plan. It is the perceived
effectiveness of the Q8 contracts management plan that can affect their overall satisfaction.
53% of the sample rated Q14 communication, reporting, sharing and use of helpdesk an
important area and it is shown to be responsible for 0.621 of the variance in Q16 providing
good value. This question covers many areas of the relationship between customer and
contractor and should be considered a fundamental deliverable that can affect the overall
customer satisfaction. This question requires modification to the wording to remove the
ambiguity in subsequent surveys. The question should address the working relationship
between contractor and customer.
4.4
Task 4 Adapt KPIs to reflect changing business needs
A list of additional KPIs were offered to the survey sample to rate their appropriateness in
influencing customer satisfaction. Two of the KPIs address this area of probity, trust and
honesty and positive customer/contractor relationship. Both were rated by 100% of the
respondents as important/very important. Relationship between customer and contractor is
an element that is key to customer satisfaction.
Trust, honesty and the relationship between customer and contractor was mentioned by 11%
of the 2007 survey respondents, in the open question at the end of the survey. This echoes
the comments received from the interviews conducted. This KPI should be introduced in
subsequent KPI surveys.
Contractors are urged by Booty (2003) [10] to be proactive and the sample agree that a
contractor should be rated on the level of initiative shown with a majority of 99% selecting it
as very important/important.
The 2007 survey sample comments in the open question
contained the following key word, which appeared more than five times “proactive”. The
area of concern is the lack of M&E contractors being proactive. The Chambers dictionary
quotes “proactive” as
“tending actively to investigate changes in anticipation of future developments, as
opposed to merely reacting to events as they occur; ready to take the initiative,
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acting without being prompted by others”
In a maintenance context for example, it is the contractor acting to resolve a problem before
being asked that demonstates a proactive approach. Measuring this is not as straightforward
as setting a goal of 5 initiatives a month but the is aimed at encouraging the sharing of ideas,
bringing new initiatives to the customer that can improve the way maintenance is carried out
or the building is operated. It is clear from the sample that this is a required deliverable,
which can affect customer satisfaction and should be included as a KPI in future surveys.
Adding value to the core business was selected by 12% of the sample as not appropriate to
measure and 18 % as not important. Interestingly this is the area that current FM journals
are promoting FM’s to demonstrate to the core business. This result indicates that 20% of
the sampled FM’s are not considering using the M&E maintenance contractors to help
accomplish this task.
4.5
Task 5 Challenging the KPIs through in-depth interviews
From the interviews it was perceived that several factors influenced the issues experienced by
the interviewee, namely the complexity of the building, size and expertise of the customers
facilities team.
The reason to outsource supports the literature review, Embleton and Wright (1998) [3], with
controlled costs and reduced headcount being commented on by all three interviewees. Of
the three interviewees those that had input into the contract document and had the opportunity
to set out their expectations were more comfortable with their contractor. The interviewee
who was not included in the procurement process had problems with the contract document
itself and the contractor’s manipulation of it.
Each of the interviewees raised the same issues as highlighted in the literature review such as
relationship, being proactive and honesty, Prior and Nowak (2003) [9]. Addressing these
customer management issues are key issues that affect customer satisfaction.
5 Conclusion Summary
When the BSRIA historical data from 2005, 2006 and the new data collection for 2007 were
examined for improvement in levels of customer satisfaction, no significant changes over time
were evident. Customers and contractors still need to be addressing the areas of
dissatisfaction they are encountering.
The conclusion of objective 1, rank importance of KPIs shows that the 2007 sample rate, Q1
quality of planned maintenance and Q2 response to breakdowns as the two must important
deliverables in rating their level of satisfaction with their maintenance contractor. These are
quantifiable measures that should be addressed at the beginning of any contract relationship.
The aim of this research was to measure customers’ satisfaction and determine which
elements of the M&E maintenance service affected overall customer satisfaction. It is
concluded that the ‘management of the contract’ above all else affects customer satisfaction of
outsourced M&E maintenance. Analysis of the results puts emphasis on management issues
such as; communication; trust and honesty; having a positive customer/contractor
relationship; being proactive and showing initiative.
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With the contractors concentrating on the relationship, developing trust and honesty, while the
customers encourage communication and initiative, maintenance contracts can aspire to
become more satisfactory for all involved.
New KPIs for the measurement of customer satisfaction of M&E maintenance should
introduce measures that include communication, customer/contractor relationship, level of
trust and honesty, initiative and being proactive.
Allery (2004) [8] states that the key to successful contracts is the clarity of the service
requirements and service levels achieved.
There were three KPIs rated in question Q21 of
the 2007 survey, which are measurable deliverables, statutory and legislative compliance,
keeping within the budget and contractor performance against SLAs. Each of these new
KPIs were rated by over 90% of the sample as very important / important. It is
recommended that performance targets should be included in maintenance contracts covering
these three KPIs.
4.1
Further work
The in-depth interviews were difficult to arrange and required more time than was allocated to
them. They provided an insight to the issues facing customers and highlighted that those
FM’s with an in-house expertise in engineering, retained responsibility for areas such as Q4
energy management and Q5 health and safety. This could influence the level of importance
the customer places on certain elements of the maintenance delivery. Further research on
this subject would benefit from a larger sample, more in-depth interviews or a focus group.
The study could address areas such as cost of maintenance contract, age of equipment, size of
building, in-house expertise and correlate that information against level of importance placed
on each KPI. This would provide useful data on the differing needs of customers.
The literature review carried out as part of this research recorded that Francis (2003) [4] and
Falconer (2006) [11] both emphasised that the customer is not undertaking adequate research
and preparation before undertaking maintenance outsourcing. The example of one
interviewee highlights that when a poorly thought through contract that doesn’t reflect the
needs of the customer can result in poor customer satisfaction. Investigation into the length
of time the contract has been running and whether the contract had been inherited or handled
by the respondent could indicate if this has an effect on the level of customer satisfaction.
The interviews highlighted that contractor liability is an area to investigate to determine if
there is a limit that still reduces the overall contract cost to the customer but also prevents
excess additional costs arising. Or is there a different style of contract that would be more
appropriate and would remove this element, thereby removing this cause of friction between
customer and contractor.
With global warming, corporate social responsibility and energy being discussed in FM
journals and at the top of the political agenda, environmental awareness was anticipated to be
very important to the sample. The results however, are not so definitive, with the sample
indicating that it is not a measure they would use for M&E maintenance contracts. Further
research into maintenance contractor’s ability to contribute to environmental issues such as
energy management, repair rather than replacement, reusing materials and managing waste
should be carried out and disseminated to the FM industry as a potential deliverable for
maintenance contractors.
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Acknowledgments. The following individuals are thanked for their time, contribution and
support while carrying out this research, Richard Harris, Lindsay Jacobs, Sarah Cudmore and
Paddy Hastings.
References
1. BSRIA.: O&M benchmarking network annual report 2005/6. BSRIA Ltd, Bracknell, UK
(2006)
2. Thompson P.: The maintenance factor in facilities management, Facilities Journal, 12:6
(1994) 13-16.
3. Embleton P.R and Wright P.C.: A practical guide to successful outsourcing,
Empowerment in Organizations, Journal of Quality in Maintenance Engineering, 6:3
(1998) 94-106
4. Francis R.: Loosen the collar, tighten the belt & pull up your socks successful
maintenance outsourcing. R Francis Consulting Pty Ltd, ICOMS. UK, (2003)
5. Varcoe B.: Facilities Performance: ‘Achieving value for money through performance
measurement and benchmarking’. Property Management 11:4 (1993)
6. Murthy D.N.P, Atrens A, Eccleston J.: A Strategic Maintenance Management,
Maintenance and Asset Management Journal, 22:1 (2007) 9-10.
7. Haynes B, Matzdorf F, Nunnington N, Ogunmakin C and Pinder J.: Does property benefit
occupiers? An evaluation of the literature, UK, Occupier.org, Report Number 1, Facilities
Management Graduate Centre, Sheffield Hallam University. (2000)
8. Allery P.: Tolley’s Effective Outsourcing: Practice and Procedures, LexisNexis Ltd, UK
(2004)
9. Prior J. J and Nowak F.: Repair it with effective partnering. Guide to contractual
relationships for cost effective responsive maintenance. Centre for Whole Life
Construction and Conservation, Building Research Establishment. UK (2004)
10. Booty F.: Facilities Management Handbook. 2nd edn. Lexis Nexis Butterworths, UK,
(2003) 235-249
11. Falconer H.: The future of facilities management outsourcing. Facilities Management.
February (2006) 10-13
12. Gonzalez R, Gasco J and Llopis J.: Information systems outsourcing success factors: a
review and some results, Information Management & Computer Security 13:5 (2005) 399418.
13. Hayward C.: Are joint ventures the perfect way to partner? FM world, Redactive
Publishing Ltd, March 2007 (2007)
14. Carder P.: Lets see you get out of VAT: the return to in-house FM? Essential FM report
63, (2007) 8-9.
15. Pallant J,: SPSS Survival Guide, Buckingham, UK, Open University Press, (2001) 49:126.
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Section 4:
Energy Efficiency
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GENHEPI: Demonstration Programme for Low Energy
Renovation
Virginie Renzi1, Laurent Sarrade1, André Manificat1, David Corgier1
1 Laboratoire d’Intégration Solaire, Institut National de l’Energie Solaire, Savoie Technolac,
BP 332 – 50, avenue du Lac Léman
73377 Le Bourget du Lac - FRANCE
{Virginie Renzi, Laurent Sarrade, André Manificat, David Corgier}@cea.fr
Abstract
Examples of high energy efficiency demonstration buildings are available, but the process is not yet generalized particularly
for refurbishment. Trying to address this problem, the GENHEPI methodology aims to help decisions-makers during the
conception phase of building retrofit operation. That goal must be achieved thanks to the development of generic guidelines
and tools and before that, the studies are based on real buildings cases. The present paper describes how the first office
building case study was carried out. In a first phase, TRNSYS is used to develop sensitivity studies on technical parameters.
Then, the building is monitored so as to obtain a necessary feedback concerning both energy consumption and comfort in
offices. The simulation results show that the primary energy consumption can easily be divided by 2 and CO2 emission by 4.
These results and the building modeling have to be validated by monitoring.
Key words
Building renovation, Energy efficiency, Dynamic simulation, Sensitivity studies
1 Context
In Europe over 40% of our energy use is consumed in buildings, more than by industry or
transport. There is a high cost-effective potential for energy savings in this sector. The
buildings sector is receiving important attention in the development of overall energy
efficiency policies. But in practise, ensuring that new buildings would be built according to
ambitious standards of energy efficiency is easier and cheaper than through retrofit of old
building stock. Yet refurbishment of existing buildings is a very important issue which should
be considered as they represent a huge part of the built environment. GENHEPI is a
methodology for low energy consumption building renovation and demonstration program.
The objective is to optimize the classic process of a renovation operation and in this aim to
generate guidelines and specific tools allowing exemplary operations to be carried out more
easily. In order to incorporate sustainability concepts in renovation projects, energy efficiency
techniques must be made affordable and applicable to existing buildings. The first office
building case study of the GENHEPI program is described in this paper. The presented
building is also integrated as a case study of the IEA ECBCS Annex 48.
2 GENHEPI Concept
The GENHEPI concept focuses on reducing consumption of primary energy and decreasing
greenhouse gas emissions in the built environment, while increasing users comfort. It aims at
methodically investigate retrofit operations to assist decisions-makers and to ensure an
effective renovation of existing buildings.
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Energy Efficiency
Three phases typically structure a restoration project: the planning phase, the conception
phase and the realisation phase. Engineering offices usually work with architects during the
conception phase. Due to a lack of both time and means, in most cases they base their studies
on past experiences rather than conducting completely new studies really adapted to each
project. Hence, architects and engineering offices actually use ratios to define the new
energetic system or the additional insulation needs. These methods result in non optimised
operations and are far from being energy efficient approaches. Indeed, not only the specificity
of each building is not considered appropriately but in addition the insufficient feedbacks
from monitoring project and experiences allow errors to be reiterated.
GENHEPI concept aims at answering these problems by creating tools and guidelines
particularly adapted to the architects, engineering offices’ work and public institutions. Before
elaborating generic tools, the studies are based on real buildings representative of a chosen
typology. Two additional phases are added in the classical process [1]. The first one is a
global approach which consists in detailed modelling analyses and sensitivity studies of
various technical solutions adapted to the project. It occurs upstream of the conception phase
and gives good orientations to the project. The second one happens downstream of the
realisation phase and consists in collecting and analysing data given by the building
monitoring.
As the concept is still in a validation phase, the work undertaken is financed both by public
institutions and research programs in which the cases study are demonstration projects. In
order to have a global vision of the renovation operation, a multi competent team is gathered.
Technical point of view can be given by researchers, engineering offices, architects and firms;
financial point of view by bank and public institutions. The point of view of users and
occupants is also carefully considered. This kind of partnership allows a better
communication and then knowledge from interactions between housing actors.
Different steps can be identified in the objectives. The first one appears in the choice of the
building typology that will be considered in GENHEPI methodology. The most important
criterion is the potential reproducibility of the operation. Indeed, a large diffusion of the
concept cannot be achieved if judicious building typologies are not selected. The first target is
the tertiary sector and more particularly office buildings since they present many similarities.
Later, the project will be opened to other types of buildings such as social housing or more
specific infrastructures like for instance gymnasium and hotels.
Two main criteria direct the technical choices: the primary energy consumption and the
greenhouse impact of HVAC systems. Sensitivity studies are carried out to reach high
performance. Typically, for the demonstration operation hereunder described the objectives
amount to a total value of 50 kWh/m².an of primary energy for heating and cooling supply,
and aim at a reduction of the CO2 emissions by a factor 4.
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
GENHE
Office buildings
TYPOLOG
IES
?
DEMONSTRATO
RS
AL
GENERIC
TOOLBOX
USERS
Dwellings, hospitals, schools, gymnasiums…
Methodological
tools
Statistical
tools
National
potential
of
energy and CO2
savings
Public
institutions
Financing
organism
?
?
?
?
BIOMERIE
Planning
Design
Decision
Statistical
tools
Methodological
tools
Planning
Design
Decision
National
potential
of
energy and CO2
savings
Engineering
offices
Works owners
Public
institutions
Financing
organism
Engineering
offices
Works owners
…
…
Fig. 1. GENHEPI methodology
3 Case Study
3.1 Building Presentation and Problems
The first case study is the ALLP head office (Association Lyonnaise de Logistique Posthospitalière – Association of Lyon for post-hospital logistics). The construction is located in
Lyon, France and was achieved in 1974. About 70 persons work in the building. A picture of
the building is presented in Figure 2.
Fig. 2. ALLP building picture before and during retrofit
The building energetic performances were poor due to an old and low-grade internal
insulation, simple glazing window and many cold bridges. A highly efficient new gas boiler
of 350 kW has been installed in 2004 [2] but in order to optimize comfort and to reduce the
energy bill, a retrofit operation had to be done. A complete diagnostic of the building and the
systems was realised by an independent engineering office in 2005; it shows a heating
consumption of about 140kWh/m².
The other problem underlined by the building owner was summer discomfort. A temperature
of 34 °C was for instance measured in June 2005 in an office of the first floor oriented toward
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Energy Efficiency
the South. Existing solar protections were unadapted and there were no mechanical ventilation
system thus fresh air came only from infiltration and opened windows. These working
conditions are not acceptable for the employees and the productivity decreased by almost
20%. This situation accounts for the intent of the ALLP managers to equip the building with
an air conditioning system.
3.2 Building Model
ALLP was modelled with the dynamic simulation software TRNSYS and the building was
split in eight thermal zones. As it is shown in figure 3, the ground floor comprises two zones
(entry rooms, lobby and workshops); the first and second floors are identically zoned in three
parts: two office zones and a common zone where comfort is not essential (staircase, etc).
Fig. 3. Description of thermal zones (eastern view)
The two office zones on first and second floors are critical because they comprise most of the
people working in the building, inducing a rather high population density and also high
internal gains.
The dynamic simulation allowed testing various options for the building components. The
principle is to consider the building from a macro scale (envelope) to a micro scale (regulation
of the energetic systems). Significant savings can be generated at each level.
4 Global Approach
One of the GENHEPI concept objectives is to decrease energy consumption while increasing
comfort. The ALLP project clearly fits in the GENHEPI spirit. The global approach consists
in parametric analysis carried out to identify the optimum technical choices. The technicoeconomical studies, hereunder described, were mainly focused on the envelope and on the
energetic systems and their regulation. An attempt was also done to improve the efficiency of
office lighting. Photovoltaic panels are disposed on the roof. The 10 kW grid connected
system will produce about 11 MWh per year.
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4.1 Envelope
Our first work was focused on the envelope and aimed at observing the influence of several
technologies on global consumption and CO2 emissions. Table 1 describes one of the
parameters whose influence was noticeable. Main thermal characteristics of glazing type are
thermal loss coefficient (U-value), solar heat gain coefficient (SHGC) and visible light
transmittance (VT).
Glazing Types
Layers (mm)
U-value (W/m².K)
SHGC (%)
VT (%)
Single
Single
2,5
5,74
85
90.1
Double
Double
2,5 / 12,7 / 2,5
2,95
72.7
81.7
Double low-e
Double – Low emissivity
3 / 12,7 / 2,5
1,76
54.4
76.9
Double low-e
Argon
Double - Low emissivity –
Argon gas fill
3 / 12,7 / 2,5
1,43
54.4
76.9
Double
Reflective
Double
layer
4,6 / 12 / 2,2
1,58
31.9
60.4
with
Table 7.
reflective
Characterisation of glazing types used in the model
Figures 4 and 5 give, respectively, the annual primary energy consumption and the CO2
emissions as a function of the glazing choice.
Yearly primary energy consumption
Primary energy (kWh/m²/yr)
120.0
115.0
110.0
105.0
100.0
95.0
90.0
85.0
80.0
75.0
70.0
Single
Double
Double low-e
Glazing Types
Fig.4. Glazing influence on annual primary energy consumption
297
Double low-e
Argon
Double reflective
Energy Efficiency
Yearly CO2 emissions
CO2 emissions (t/yr)
55.0
50.0
45.0
40.0
35.0
30.0
Single
Double
Double low-e
Double low-e
Argon
Double reflective
Glazing Types
Fig.5. Glazing influence on annual CO2 emissions
For both energy consumption and CO2 emissions, a minimum appeared for low-emissivity
double glazing filled with Argon. Double glazing with reflective layer would have been the
best choice if only the summer comfort had been considered.
In this case study, limitation of solar gains by windows actually increases heat demand and
affects global assessment. Such analyses have been carried out for other parameters like night
ventilation rate or insulation thickness. Once best technical choices were done, simulated
building performance remained lower than GENHEPI objectives. Also the problem of
summer overheating was not solved as the temperature still reached 28°C. A work on the
energetic system must complete the work on building envelope.
4.2 Energetic Systems
An air conditioner system generates important energy consumption but is necessary to
maintain summer comfort in offices. A reversible heat pump coupled to the existing gas boiler
could address the comfort problem with a decrease of the heat consumption. This energetic
system has been simulated for the ALLP building.
Figure 6 displays the performances of three systems. An air conditioner (AC), an air/water
heat pump (HP A/W) and a water/water heat pump (HP W/W) were compared. The latter was
considered because of local ground water presence.
Two kinds of regulations were studied for A/W heat pump. The first one aims to minimize
CO2 emissions and the second one the primary energy consumption. To minimize CO2, the
heat pump has to work continuously since, in France, an average electric kWh contains less
CO2 than a gas kWh, whereas, to minimize primary energy consumption, the heat pump has
to be switched off as soon as its performance coefficient becomes lower than 2,58 (conversion
factor which links final and primary energy for electricity in France).
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Primary Energy (kWh/m²/yr)
32.7
Regul CO2
7.2
68.4
Regul CO2
12.7
66.5
Regul Ep
19.5
77.6
AC
HP A/W
HP W/W
CO2 emissions (t/yr)
34.5
Fig.6. Energetic system performances
The highest performance system was obviously the W/W heat pump. However, an A/W heat
pump was chosen due to a better reproduction potential of the renovation operation. The
minimisation of CO2 emissions was selected but the possibility to change the kind of
regulation was kept.
4.3 Regulation Systems
Once the system selected, the study can go further by estimating the potential energy saving
generated by different water temperature conditions in the heat pump. Figure 7 displays the
performances for three cases. For the refreshing mode, temperature conditions simulated for
the evaporator are 7-12°C, 10-15°C and 12-17°C. Respectively, for the heating mode
temperatures tested at the condenser are 40-35°C, 38-33°C and 35-30°C.
67.3
1000.0
61.2
58.5 887.8
60.0
900.0
800.0
50.0
700.0
600.0
591.2
40.0
500.0
30.0
20.0
400.0
300.0
12.8
11.4
11.0
10.0
0.0
200.0
Savings (Euros/year)
Primary energy consumption
(kWh/m².yr) and CO2 emissions (t/yr)
70.0
100.0
0.0
0.0
7/12°C & 40/35°C 10/15°C & 38/33°C12/17°C & 35/30°C
Primary energy consumption
CO2 emissions
Savings
Fig.7. Impact of different water temperature conditions on the energetic system performances
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Energy Efficiency
These different conditions affect the performance of the heat pump as well as the sizing of the
distribution channel and it is thus important to compromise between the two. A quick
valuation of the economic rate of return generated by the distribution units investment, led to
the choice 10-15°C and 38-33°C.
5 Monitoring
Once the refurbishment is done, the monitoring of the building will allow carrying out the
second phase of the GENHEPI process. The installation of a Building Management System
(BMS) was included in the renovation process. It will permit to automate, control and monitor
the building as efficiently as possible. The tele-supervision of ALLP will be done by a BMS
that integrate an internet protocol. The use of web technology will allow remote access and
permit a lot of freedom in the data acquisition. All data should be available by May 2008 on
www.genhepi.com.
Two levels of monitoring are developed. The first one aims at analysing the global behaviour
and consumptions of the building (including the energetic system efficiency). The second
focuses on comfort conditions in various test offices.
5.1 Global Monitoring
The global behaviour of the building will be followed by:
-
5 external irradiance sensors (1 on each facade + 1 on terrace)
-
8 environment sensors
-
3 energy meters (boiler outing, heat pump outing, distribution main)
-
1 gas meter
-
7 electric meters (energy and power)
Measures will also be done for the different systems: heat pump, boiler, light, internal gains,
photovoltaic production. The frequency of acquisition depends on the data measured (a time
step of ten minutes is usually used, expected during transient phase of the heat pump when it
is significantly reduced). The duration of the data processing will vary (daily, weekly and
monthly). Results will be available through reports and graphs published on internet.
The global monitoring will help to achieve optimal performance of the building by
responding to any changes and act accordingly. It will allow obtaining a necessary feedback
concerning energy consumption and comparing measurements to calculation results. A longer
period observation will allow evaluating the TRNSYS model accuracy and consistency. The
BMS will finally help to subsequently develop tools and guidelines.
5.2 Local Monitoring
The local monitoring is essential to evaluate the capacity of technical choices (envelope and
the energetic system) to ensure comfort in critical offices. The figure 8 illustrates the way
those critical offices are monitored.
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Nort
Nord
So
Sud
uth
h
4 test offices
Presence detector
Wireless air temperature sensor
Air temperature sensor
Magnetic contact switch
Integrating sphere
Humidity sensor
Fig.8. Description of test office monitoring
The system will permit to retrieve a wide range of data and real-time information. Four
offices will be fully equipped with wireless sensors and will serve as test offices (2 northerly,
2 southerly). Instrumentation in each test office will be:
-
1 integrating sphere (comfort – operating temperature)
-
8 ambient temperature sensors (homogeneity)
-
2 air temperature sensors (air flow)
-
1 presence detector (occupancy patterns)
-
3 magnetic contact switch (natural ventilation)
-
1 relative humidity sensor
A complete study of thermal comfort was done by an independent organism just before the
refurbishment operations [3]. Different data (temperatures, humidity, air velocity) were
measured during the third week of June 2007 in order to highlight summer overheating. Some
employees were also surveyed. The results revealed a comprehensive dissatisfaction of users.
This kind of study should be reiterated next summer, to evaluate the performances of the
renovated building and of the new systems.
6 Conclusions
For this first GENHEPI case study, significant energy savings will be allowed by addressing
energy efficiency issue during the early stages of project development. Instead of installing an
air conditioning system, a global work was carried out both on the envelope and on the
energetic system and their regulation. The building modelling and simulation with TRNSYS
allowed helping technico-economical decisions. The monitoring will allow comparisons
between real building performance and predicted values and thus validation of the building
model. Simulation studies foresee that the primary energy consumption will be divided by 2
and CO2 emissions by 4. The famous factor 4 on CO2 seems then available, even in
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Energy Efficiency
renovation operations. The common typology of the ALLP building leaves to think that such
an operation can be easily reproduced. The monitoring phase is now in place and the results
should be soon available.
References
1. Sarrade L, Manificat A and Corgier D : Rapport d’activité GENHEPI - CEA–INES RDI
(2006)
2. Sarrade L : Optimisation des systèmes thermiques intégrant une pompe à chaleur et mise
en application dans le projet de rénovation d’un bâtiment tertiaire - CEA/Institut ENSAM
de Corse (2005)
3. Barbat M, Gallois C : Mesures de confort thermique dans le bâtiment ALLP – LYON –
COSTIC (2007)
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Towards an Automated Technique for Optimising the Design of
Thermosyphon Solar Water Heaters
M.J.R. Abdunnabi and D.L. Loveday
Department of Civil and Building Engineering, Loughborough University, Loughborough,
Leicestershire, LE11 3TU, United Kingdom
{m.j.r.Abdunnabi; d.l.loveday}@lboro.ac.uk
Abstract
Modelling the thermal performance of thermosyphon solar water heaters is a complex process. Component Type 45 in the
well-known TRNSYS simulation program is the main component that can be used for evaluating the thermal performance of
thermosyphon solar water heaters. This model-based component requires certain information that must be determined
experimentally in order to eliminate errors that would result if performance was calculated theoretically. The use of this
component is therefore limited to evaluating the performance of existing systems and their components based on test results.
Hence, model-based optimisation can lead to possible errors in some of the design parameters of a thermosyphon system.
This is thought to be due to the fact that values of collector performance characteristics and tank overall heat loss coefficient
are kept fixed throughout the optimisation process whereas they change as other variables are altered.
In this study, a new component is added in order to correct the situation, as well as to change the characteristic performance
of the collector from being parameters to instead being inputs to the current version of Type 45. The study has shown that
linking this component with the modified thermosyphon-collector component Type 145 (referred to as ‘Modified TRNSYS
Model’) gives results that agree to within RMS error of less than 5.6% with the traditional way of evaluating system
performance (solar fraction) by using Type 45 (referred to as ’Original TRNSYS Model’). Furthermore, the modified
TRNSYS model eliminates restrictions on design parameter optimization and gives a wider choice for conducting parametric
studies. This represents an essential first step towards development of a tool for optimising the design of thermosyphon solar
water heating systems.
Keywords
thermosyphon solar water heater, TRNSYS, new TRNSYS types, validation
1. Introduction
Thermosyphon solar water heaters are pump free-devices used to provide households with
the required hot water. Basically, part of the required energy comes from the sun and the
remaining part comes from conventional energy sources to meet the desired set temperature.
The operating theory of these systems depend mainly on buoyancy, the difference in the
density between the warmer liquid in the solar collector side and the colder liquid in the
storage tank side. This causes an imbalance in the gravitational forces in the loop which
causes the liquid to circulate naturally and transport the heat from the collector to the storage
tank. This process continues for as long as the solar irradiance is enough to make this
difference in densities.
Thermosyphon systems are very attractive devices, and are the most popular installed
systems in moderate and hot climates due to many reasons, the most significant of which are
less cost compared with active systems and less maintenance requirement since they have no
moving or control parts.
In the literature there have been many attempts to model thermosyphon solar water heaters
[1-11] and most of them have failed to accurately represent the system. To date, there
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Energy Efficiency
appears to have been no attempt to improve on, or to create, new models that treat the system
more rigorously. The only program available and used by most researchers in this field is the
TRNSYS Type 45. This model has been validated by a number of researchers [12,13] and has
been used frequently to investigate, evaluate and optimise the thermal performance and the
design parameters of thermosyphon solar water heaters [14-20].
The thermosyphon component in the TRNSYS program, Type 45, requires a number of
experimentally-determined items of information (namely, FRτα , FRU L , bo , U 1 , U 2 , UAt ).
This, in turn, requires that evaluation or optimisation of a system should be carried out on an
already existing system where the components are already tested and reported. No doubt,
evaluating the thermal performance of the system in the presence of experimentallydetermined information will give more accurate results than calculating that information
theoretically. However, in the case of optimisation, keeping that information fixed, despite the
fact that its values change throughout the optimisation process, will probably lead to
inaccurate results. Therefore, recourse to theoretical models to re-calculate those values
during the optimisation process would be better for obtaining more accurate results.
In this study, an attempt is made to achieve a better estimation of the effect of changing
design parameters on the thermal performance of a thermosyphon system. A new component
was added to the TRNSYS model to account for the collector performance characteristics
( FRτα , FRU L , bo ). This component is named : collector characteristics (Type 210)
2. TRNSYS New and Modified Components
2.1
TRNSYS Simulation Program
TRNSYS is a transient simulation program with a modular structure, developed at the Solar
Energy Laboratory of the University of Wisconsin [26]. The program is comprised of many
subroutines that model subsystem components. Each of these component subroutines is
identified by a Type number. The modular nature of TRNSYS permits the simulation of a
great variety of thermal systems.
TRNSYS has the capability of interconnecting system components in any desired manner,
and the entire problem of system simulation reduces to a problem of identifying all of the
components and formulating a general mathematical description of each [26].
Further to the library of components already provided in the TRNSYS package, it is
possible to add one’s own components to become part of the TRNSYS library components
and then benefit from the other components to build bespoke models.
The standard component of thermosyphon systems in TRNSYS 16 is component Type 45
which consists of a flat plate solar collector, a stratified vertical or horizontal storage tank, and
a check valve to prevent reverse flow. Stratification in the tank is modelled using the Type 38
algebraic component, which is called by Type 45. Further components need to be connected
with Type 45 in order to complete the modelling of the system.
2-2
Collector characteristics component (Type 210)
The flat plate solar collector, which is considered to be the most important part of a
thermosyphon solar water heating system, is a very special type of heat exchanger that
converts solar radiation into thermal energy for heating the working fluid that passes through
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
it. The collector consists of many parts that need to be sized properly for efficient collector
design. This, of course, requires accurate knowledge of collector thermal analysis. In fact, the
thermal analysis of the flat plate solar collector remains a very difficult problem due to the
structure and complexity of the collector, and hence assumptions are imposed to simplify the
analysis. The literature has revealed a great deal of work devoted to the study and modelling
of flat plate solar collectors. From the literature, this study examines four models, with the
aim of identifying the best one for further analysis and modelling. The models under
consideration are: i) CoDePro program[23]; ii) Kirchhoff and Billups model (named as Model
1) [22]; iii) Prabhakar et al model [21] (Model 2); and iv) model 1 with a different boundary
condition between the absorber plate and riser tubes (this model is denoted here as Model 3).
‘CoDePro’ is a software programme provided by Wisconsin University that is available
online [23], its model being based on the Hottel, Whillier, and Bliss equation. The other three
models (models 1,2 and 3 referred to earlier) consist of differential equations governing the
temperature distribution of the plate, glazing cover, and fluid, these being solved numerically
by using the finite difference approach.
The resulting predictions from these models are compared with data determined
experimentally for three collectors tested according to standard EN 12975-2. Figure 1 shows
the comparison between prediction and experiment.
In order to evaluate these models, the average root mean square (RMS) error of the results
is used. Model 3 shows good agreement with the experimental data to within an RMS error of
less than 1.06%. This compares with RMS errors of the other three models as 2.21%, 2.7%
and 1.21 % for CoDePro, Model 1 and Model 2, respectively. Predictions from Model 3 thus
gave the least RMS error and therefore Model 3 was chosen to represent the characteristic
performance of the flat plate solar collector (Type 210) in this study.
2-3- Modified Thermosyphon-Collector Component Type 145
The thermosyphon-collector component model Type 45 has been slightly modified to
accept the output of the new component mentioned above in section 2-2 as an input. In fact,
no modifications are made in the main body of this component, the only change is to alter the
three parameters ( FRτα , FRU L , bo ) in Type 45 from being parameters (in the TRNSYS
terminology) to instead being inputs. This will enable their values to vary during the
simulation.
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Energy Efficiency
0.85
Experiment
CoDePro
Model 1
Model 2
Model 3
0.8
0.75
efficiency
0.7
0.65
0.6
y(exp) = -4.3665x + 0.7662
0.55
y(co) = -4.379x + 0.7826
y(m1) = -4.965x + 0.817
0.5
y(m2) = -4.793x + 0.781
y(m3) = -4.365x + 0.781
0.45
0.4
0
0.01
0.02
0.03
0.04
0.05
0.06
(Tm-Ta)/Gt
Figure 1: Experimental and theoretical efficiency curves
3. Original and Modified TRNSY Models
In this study, the usual TRNSYS procedure to model thermosyphon solar water heaters is
referred to as the ‘Original TRNSYS Model’ (OM). It comprises the following main
components: thermosyphon-collector component Type 45, weather data component Type109,
load profile Type 14, in addition to a flow mixer and diverter, output and utility components
(see Figure 2a). The modified model is referred to as ‘Modified TRNSYS Model’ (MM),
and comprises the thermosyphon-collector component Type 145 as modified in this study,
collector characteristics components Type 210, weather data component Type 109, load
profile Type 14, in addition to a flow mixer and diverter, output and utility components (see
Figure 2b).
Type109
Type45
Flow
mixer
Output
devices
Flow
diverter
Type14
Figure (2 a) Schematic diagram of the major components of the original model
4. Model Validation
Comparison between the modified TRNSYS model and the original TRNSYS model was
made on two thermosyphon systems (system 1 and system 2) each having specifications as
described in Table 1. In the comparison, it is assumed that the daily quantity of hot water
withdrawn is 150 litres at 60 ºC, and is withdrawn according to the simple load pattern as
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
shown in Figure 3. The system is assumed to be located in Libya, and weather data for Tripoli
Airport, Libya, as provided by TRNSYS, is used in this study.
The monthly and yearly solar fractions have been used as the measure for thermal
performance of the thermosyphon system for both cases (original and modified models).
Figure 4 shows the monthly solar fraction of System 1. It is clear that there is little
difference between the original and modified models. The modified model predicts slightly
higher values of monthly solar fraction (by no more than 2.9%) as compared to the original
model, whereas the error in estimating yearly performance is less that 2%.
Type 210
Type109
Flow
mixer
Type245
Flow
diverter
Type14
Output
devices
Type211
Figure (2 b) Schematic diagram of the major components of the modified model
Table 1 system features
System 1
Ac
2.272 m2
F τα 0.679
R
FRU L
13.77
kJ/h m2
Gtest
Dr
Dh
Nr
Di, Do
Hc
72
kg/h m2
6.4 mm
22 mm
8
22 mm
1.47 m
Ho
Lh
Li
Lo
1.63 m
1.087
3.2 m
1.05 m
Vt
UAt
U1 ,
U2
Vload
Ht
Hr
Hth
Haux
NB1,
NB2
Paux
Tmain
Tset
β
150 lit
7.50 kJ/h
System 2
Ac
2.489 m2
F τα 0.6791
8.79
kJ/h m2 k
FRU L
14.6052
kJ/h m2
150
Lit/day
0.71m
0.66 m
0.61m
0.56 m
4
Gtest
Dr
Dh
Nr
Di, Do
Hc
72
kg/h m2
7.0 mm
22 mm
10
22 mm
1.39 m
10 MJ/h
20 ºC
60 ºC
45 deg
Ho
Lh
Li
Lo
1.55 m
1.24
3.07 m
1.05 m
R
Vt
150 lit
7.50 kJ/h
UAt
U1 ,
U2
8.79
kJ/h m2 k
Vload
Ht
Hr
Hth
Haux
NB1,
NB2
Paux
Tmain
Tset
β
150
Lit/day
0.71m
0.66 m
0.61m
0.56 m
4
10 MJ/h
20 ºC
60 ºC
45 deg
In a similar way, the agreement between original and modified TRNSYS models in the case
of System 2 is also very good as can be seen from Figure 5, with slightly higher predictions of
monthly solar fraction by the modified model of no more than 5.6%, and the yearly error
prediction of less than 3.9%.
It is concluded that the errors incurred by calculating theoretically the characteristic
performance parameters of the collector instead of measuring them experimentally can be
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Energy Efficiency
considered acceptable when viewed against the benefit of allowing greater flexibility for the
purpose of evaluating and optimising thermosyphon systems. To demonstrate the capability of
the approach, the modified TRNSYS model (MM) will be used in this study to predict the
optimum collector area of the thermosyphon solar systems (system 1).
0.16
Normalized Usage
0.14
0.12
0.1
0.08
0.06
0.04
0.02
0
0
4
8
12
16
20
24
Time(hr)
Figure 3: Hot water load pattern used for the study
0.85
0.80
Solar Fraction
0.75
0.70
0.65
0.60
MM
OM
0.55
0.50
0.45
1
2
3
4
5
6
7
8
9
10
11
12
Months
Figure 4 Monthly solar fraction of System 1
5. Optimum Thermosyphon System Design
The modified TRNSYS model is used for finding the optimum collector area of system 1.
The strategy used to find the optimum area is to determine the optimum distance between
risers and the optimum aspect ratio of the collector of system 1. Accordingly, the optimum
collector area can be found.
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
0.90
0.85
Solar Fraction
0.80
0.75
0.70
0.65
0.60
MM
OM
0.55
0.50
0.45
1
2
3
4
5
6
7
8
9
10
11
12
Months
Figure 5 Monthly solar fraction of System 2
Figure 6 shows the effect of changing the number of risers on the system performance. Of
course, changing the number of risers per unit area will change the distance between the
risers, therefore, from the optimum number of risers we can find the optimum distance
between risers (fin width). It is clear from Figure 6 that the optimum number of risers is 9,
and the corresponding distance between risers is 0.113m.
0.75
0.7
Solar Fraction
0.65
0.6
0.55
0.5
0.45
0.4
2
4
6
8
10
12
14
16
18
20
Number of Risers
Figure 6 Effect of number of risers on the system yearly solar fraction
The effect of changing the aspect ratio of the collector on the system solar fraction is shown
in Figure 7. It clear that the optimum aspect ratio is between 1.75 and 2.0 . Therefore, the
optimum value is taken as 1.95 to find the optimum collector area.
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Energy Efficiency
0.71
0.705
Solar Fraction
0.7
0.695
0.69
0.685
0.68
0.675
0.67
0.35
0.75
1.15
1.55
1.95
2.35
2.75
3.15
3.55
3.95
Collector Aspect Ratio (Lc/Wc)
Figure 7 Effect of collector aspect ratio on system yearly solar fraction
The optimum values of riser distance (0.113m) and collector aspect ratio (1.95) were then
used together with the other properties of system 1 (except for the collector characteristics
performance which will be calculated in the modified TRNSYS model) to determine the
optimum collector area. It can be seen from Figure 8 that beyond a collector area of 4m2 the
increase in solar fraction is accompanied with high increase in collector area. Therefore, the
optimum collector area would be 4m2 in this case. This area will provide about 94% of the hot
water demand from solar energy.
1
0.9
Solar Fraction
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
1
2
3
4
5
6
7
8
Collector Area m2
Figure 8 Effect of collector area on the system yearly solar fraction
6. Conclusions
A new component has been added to TRNSYS for use with the modified thermosyphoncollector (Type 145) to predict what would otherwise have to be experimentally determined
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
information ( FRτα , FRU L , bo ). The new component was validated against three different
sets of experimental data and good agreement was obtained between the model predictions
and experimental results with an average RMS error of 1.06%. The model was incorporated
into a modified TRNSYS thermosyphon model (MM), the latter giving close agreement with
the results of the original TRNSYS thermosyphon model (OM) when tested with two
different thermosyphon systems, System 1 and System 2, but with the added advantage of
enhanced flexibility for modelling and subsequent optimisation. This is demonstrated through
the use of the modified TRNSYS model to predict the optimum collector area of 4 m2
required for a thermosyphon system (system 1) to provide 150 litres of daily hot water at 60
ºC, in Tripoli, Libya. It is concluded that the modified TRNSYS model developed in this
paper can be used for parametric investigations of thermosyphon systems. The model offers
the ability to vary collector characteristics as predicted during the calculation, as opposed to
using fixed values determined from measurement, and represents an important step towards
development of an automated technique for optimising thermosyphon system design.
Nomenclature
Ac
bo
Dh
Di,
Do
Collector area m2
Incidence angle modifier coefficient.
Header diameter (m)
Inlet and outlet
diameters (m)
Riser diameter (m)
Li, Lo
NB1,
NB2
Nr
connecting
pipes
Nu
Lengths of inlet and outlet pipes (m)
Number of equivalent right angle
bends in inlet and outlet connecting
pipes.
Number of risers
Nusselt number
FRτα
Intercept of the collector efficiency curve
Tset
Auxiliary energy input to tank
(KJ/hr)
Auxiliary heater setting temp (°C)
FRU L
Slope of the collector efficiency curve
UAt
Overall UA value for tank (KJ/hr ° C)
Dr
Paux
Gtest
Collector flow rate at test condition
(kg/s m2)
Haux
Auxiliary heater position height (m)
Hc
Ho
Hr
Ht
Collector perpendicular height (m)
Height from datum to the tank bottom (m)
Upriser height from the tank bottom (m)
Tank height (m)
Hth
Thermostat position height (m)
Lh
for inlet and outlet
U 1 , Loss coefficients
2
°
C)
pipes
(KJ/hr
m
U2
Heat transfer coefficient between
U fw
2
Vload
Vt
β
δf
ΔX
water and fin (W/m K)
Hot water load (Lit/day)
Tank volume (Lit)
collector tilt angle (deg)
Fin material thickness (m)
Step thickness in the X-direction
(m)
Header length (m)
References
1. Close, D.J., 1962, The Performance of Solar Water Heaters with Natural Circulation, Solar
Energy.
2. Gupta, C. L. and H. P. Garg, 1968, System design in solar water heaters with natural
circulation, Solar Energy, 12, 163-182.
311
Energy Efficiency
3. Ong, K. S., 1974, A finite difference method to evaluate the thermal performance of a
solar water heater, Solar Energy, 16,137-47.
4. Ong, K. S. , 1976 An improved computer program for the thermal performance of a solar
water heater, Solar Energy, 18, 181-191.
5. Sodha, M.S. and N. Tiwari, 1981, Analysis of natural circulation solar water heating
systems, Energy Conves. & Mgm., 2, 283-288.
6. Mertol, A., Place, W., Webster, T., and Greif, R., 1981, Detailed Loop Model (DLM)
analysis of liquid solar thermosyphon with heat exchanger, Solar Energy, 27, 5, 367-386.
7. Morrison G.L., and Tran, H.N., 1984, Simulation of the long term performance of
thermosyphon solar water heaters, Solar Energy, 33, 6, 515-526.
8. Hobson, P.A., and B. Norton, verified accurate performance simulation model of direct
thermosyphon solar energy water heaters, Transaction of ASME, J. of solar Energy, 110, 4,
282-292,1988
9. Morrison G.L. and Sapsford, C.M., Long term performance of thermosyphon solar water
heaters, Solar Energy, 1983, 30, 341-350
10. Malkin, M. P., Klein, S. A.; Duffie, J. A., Copsey, A. B., Design methods for
thermosyphon solar domestic hot water systems, Journal of Solar Energy Engineering,
Transactions of the ASME, 1987, 109,2, 150-155.
11. Huang, B.J. and Hsieh, C.T., 1985, A simulation method of solar thermosyphon collector,
Solar Energy, 35, 31-43.
12. Soteris A. Kalogirou and Christos Papamarcou, Modelling of a thermosyphon solar water
heating system and simple model validation, Renewable Energy, 21, 471-493, 2002
13. Morrison, G. L. and J. E. Braun, 1985, System Modelling and Operation characteristics
of thermosyphon solar water heaters, Solar Energy, 34, 389-405
14. Michaelides I.M., Lee W.C., Wilson D.R., and Votsis P.P., 1992, Computer simulation
performance of a thermosyphon solar water heater, Applied Energy, 41, 149-163
15. Michaelides I.M., and Wilson D.R., 1997, Simulation studies of the position of the
auxiliary heater in thermosyphon solar water heating systems, Renewable Energy, 10, 1,
35-42
16. Shariah, A. and Shalabi, B., Optimal design for a thermosyphon solar water heater,
Renewable Energy, 11,3,351-361, 1997.
17. Shariah, A. M., Douglas, C. Hittle and Lof, G.O.G, computer simulation and optimization
of design parameters for thermosyphon solar water heater, Joint solar Engineering
Conference ASME, 1994, 393-399
18. Shariah, A. M. Rousan A., Rousan K.K., Ahmad A.A., Effect of thermal conductivity of
absorber plate on the performance of a solar water heater, Applied thermal Engineering,
1999, 19, 7, 733-741
19. Hasan A., 1997, Thermosyphon solar water heaters: effect of storage tank volume and
configuration on efficiency, Energy Conversion and Management, 38, 9, 847-854.
20. Shariah, A.M. and G. O. G. Löf, 1996, The optimization of tank-volume-to-collectorarea ratio for a thermosyphon solar water heater ,
Renewable Energy, 7, 3 289-300.
21. Prabhakar P. Rao, John E. Francis, and Tom J. Love Jr., 1977, Two-dimensional Analysis
of a flat-plate solar collector’, Journal of Energy,1,5,5-12.
22. R. H. Kirchhoff, M. Billups, 1976, A two dimensional heat transfer model of a flat plate
collector, ASME conference paper number 76-WA/Sol-2, ASME, New York, U.S.A.
23. http://sel.me.wisc.edu/codepro/new_codepro.html
24. John H. Lienhard IV and John H. Lienhard V, A Heat Transfer Textbook, 3rd edition,
Phlogiston Press, Cambridge, Massachusetts, U.S.A. 2006.
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
25. ISO 9459-2, Solar heating -- Domestic water heating systems -- Part 2: Outdoor test
methods for system performance characterization and yearly performance prediction of
solar-only systems, 1995.
26. Klein, S.A., et al, 1990, TRNSYS : a transient simulation program, Solar energy
Laboratory : Madison University of Wisconsin, USA.
313
Energy Efficiency
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Underground Thermal Energy Storage
for Efficient Heating and Cooling of Buildings
Marcel Hendriks1,3, Aart Snijders1, Nick Boid2
1
IFTech International BV, de Gewanten 8, 6836 EB Arnhem, Netherlands
2
IFTech Ltd, 62-68 Rosebery Avenue, London EC1R 4RR, UK
3
IFTec GeoEnergía SL, C/Doctor Esquerdo 10 4º centro, 28002 Madrid, Spain
Abstract
Underground Thermal Energy Storage (UTES) systems and Ground Source Heat Pump (GSHP) systems use the underground
for exchange of thermal energy (heat and “cold”) for efficient heating and cooling of buildings. The application of GSHP
systems is based on the natural ground temperature. The GSHP extracts heat from the ground in winter and injects heat into
the ground in summer. The application of UTES systems is based on the storage of heat and “cold” in the underground for
later use. The stored thermal energy can be used for direct heating or cooling, but can also be used in combination with a heat
pump. In general two types of UTES can be distinguished: ATES (Aquifer Thermal Energy Storage) and BTES (Borehole
Thermal Energy Storage). GSHP and UTES systems are applied in various European countries. In some countries these
systems are already considered as a standard design option for heating and cooling. In other countries the application of the
technologies is quite recent. The application of GSHP’s , ATES and BTES is quite different for the various countries
considered in this paper (Belgium, Denmark, Germany, Netherlands, Spain, Sweden and the UK) . Some of these differences
can be explained by climatological conditions and underground conditions. However, the presence of clear energy efficiency
targets for buildings and the availability of the GSHP and storage technologies on the market seem to be the major
explanation for these differences.
Keywords
Efficient heating and cooling, ATES, BTES, Energy saving, Reduction in Carbon Dioxide Emission
1
Introduction
Underground Thermal Energy Storage (UTES) refers to the use of the ground for storage and
exchange of heat and “cold” for the purpose of providing efficient heating and cooling for
buildings. It has been demonstrated as a viable heating and cooling system for residential,
commercial and institutional buildings throughout Europe and North America. UTES has a
wide range of applications for efficient heating and cooling of buildings. In the Netherlands
over 500 projects have been realised in which UTES is applied. In other countries, like the
United Kingdom and Spain, the implementation of UTES for heating and cooling of buildings
is new. However, because of the need for energy saving and reduction in CO2 emissions the
interest is growing, resulting in the realization of the first projects in these countries. In this
paper we will present the status of UTES in various European countries with some examples
of typical applications.
2
GSHP and UTES Technologies
2.1 Ground source Heat Pumps
A ground source heat pump (GSHP) is a heat pump that uses the ground as either a heat
source, when operating in heating mode, or a heat sink, when operating in cooling mode. For
the exchange of thermal energy the GSHP is connected to the ground with a loop. The most
common connection is a closed loop, existing of U-tubes of high density polyethylene
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Energy Efficiency
inserted into boreholes of 50 to 200 meters deep. A less common design is the direct use of
water from an aquifer (often called an open-loop system). One or several wells supply the
water necessary for a GSHP application, a similar number of wells would be used to inject the
water.
The application of a GSHP system is based on the natural ground temperature. The GSHP
extracts heat from the ground in winter and injects heat into the ground in summer.
2.2 Underground Thermal Energy Storage
Whereas a GSHP extracts or injects heat, is UTES based on the storage of heat and “cold” in
the underground for later use. In most cases UTES is applied as a seasonal storage. The stored
energy can be used for direct heating or cooling, but it can also be used in combination with a
heat pump. In general two types of UTES can be distinguished:
1) ATES:
Aquifer Thermal Energy Storage
2) BTES:
Borehole Thermal Energy Storage
2.2.1 ATES
An ATES system is a large open-loop system optimized and operated to realize seasonal
thermal storage, i.e. by reversing extraction and injection wells seasonally. The principle is
shown in Figure 1.
In summer, groundwater is extracted from the cold well(s) and used for cooling purposes. The
warmed up water is injected in the warm well(s). In winter the process is reversed. Water is
pumped from the warm well(s) and applied as a heat source, e.g. as low temperature heat
source for a heat pump. The heat pump supplies (part of) the heating. The chilled groundwater
is then injected into the cold well(s) again. With ATES no groundwater is discharged. All the
water extracted from one well is re-injected in another well. This means that there is no net
extraction of groundwater from the soil, which minimizes negative impacts on the
environment. ATES systems require that relatively high well yields can be obtained on site.
Because of this the applicability depends strongly on site-specific hydrogeological conditions.
2.2.2 BTES
A BTES system consists of a radial, circular array of boreholes resembling standard drilled
wells. Rather than penetrate the aquifer as in the ATES system, BTES is closed loop and after
drilling, a plastic pipe with a “U” bend at the bottom is inserted down the borehole. To
provide good thermal contact with the surrounding soil, the borehole is then filled with a high
thermal conductivity grouting material. The principle is shown in Figure 2 en Figure 3.
During winter the borehole heat exchanger is used for extraction of heat from the ground, e.g.
as heat source for a heat pump. While the circuit water passes through the heat pump the
temperature of the water cools down. The chilled circuit water is returned in the borehole heat
exchanger and the ‘cold-energy’ is stored in the ground. In summer the flow in the BTES
system is reversed. The stored cold is extracted and passed through a heat exchanger
providing direct cooling to the building. When necessary the (reversible) heat pump can be
put in use as peak load chiller as support in periods of peak cooling demand. The store circuit
water will pick up energy from the building and thus be raised in temperature. This water, the
temperature of which is higher than the ground temperature, will be returned in the borehole
heat exchanger where the ‘warm energy’ is stored in the ground around the boreholes for the
next heating season. Closed-loop BTES systems depend less on site-specific hydrogeologic
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
conditions than ATES systems and are better suited for areas where relatively high well yields
are not obtainable.
Fig. 21. Principle of ATES.
-
Heating
-
+
+
H
H
H
H
H
H
Cooling
Flow of
Flow of
Fig. 2. Principle of BTES (HP = heat pump / HE = heat exchanger).
317
Energy Efficiency
Fig. 3.
3
Aerial view of BTES field and side view of single borehole.
Applications and experiences in various European countries
GSHP and UTES systems are applied in various European countries. In some countries these
systems are already considered as a standard design option for heating and cooling. In other
countries the application of the technologies is quite recent. Between the various countries
applying GSHP and UTES systems already, there are significant differences in the number
and type of applications (see Table 1).
Table 1: Implementation of GSHP and UTES systems in various European countries
GSHP
ATES
BTES
Belgium
Denmark
Germany
Netherlands
Spain
Sweden
United Kingdom
••
••
•
•••
••
‐
••••
•
•••
•••
••••
••
•
‐
‐
••••
•••
••••
••
•
•
•
••
few applications
•••
••••
many applications
some applications
very many applications
3.1 Belgium
The acceptance of using underground thermal energy storage for applications where heating
and cooling is required, is slowly forcing a way in Belgium without being a “booming”
market. More than ten ATES systems are in operation. All large scale (> 500 kWcooling) and
most of them are located in the Campine (region of Flanders). The applications are mainly
related to combined cooling and heating of office buildings and hospitals. Due to the
hydrogeological limitations, the most populated regions and cities of Belgium are not suitable
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
for ATES. In this regions BTES could be applied. The interest in BTES applications is
slightly growing with several feasibility studies underway and a few realized projects [1].
Photo 1: “Zonnige Kempen”, Westerlo
(Belgium). Social housing project with
BTES in combination with solar panels and
asphalt collector
GSHP systems are applied for
heating of single family houses all
over the country. The number of
installed heat pumps is growing. In
2000 less than 400 heat pumps were installed. In 2005 the number was increased to over
2,600 .
3.2 Denmark
By the end of 2007, over 1,000 GSHP’s will be operational in Denmark, as well as about 25
groundwater cooling projects [2]. As far as known, no BTES projects will be operational in
Denmark by that time. The majority of the groundwater cooling projects provide direct
cooling to industrial applications. In general, the warm groundwater is reinjected into the
aquifer without thermal balancing.
Recently, there is a growing interest in the application of ATES for the heating and cooling of
buildings. The first project of this kind was operational by the end of 2007. The major reason
for this increasing interest is the introduction of the European Energy Performance Directive
for Buildings.
Lack of awareness is considered to be the major bottleneck to the application of GSHP’s and
UTES technologies in Denmark.
3.3 Germany
Only a few ATES projects have been installed in Germany. The number of BTES projects,
however, amounts to several hundreds. The major application is for heating and combined
heating and cooling of small commercial and residential buildings (BTES capacity in the
range of 50 - 500 kW). A few BTES projects are applied for seasonal storage of solar heat at
relatively high temperatures (60 - 90º C).
The total number of GSHP applications in Germany is about 90.000 - 100.000. Heating and
combined heating and cooling of single family homes are the major applications of this
technology. About 15% of the GSHP systems are open loop systems, 85% are closed loop
systems, either with vertical U-tubes (60 - 70% of the closed loop systems) or horizontal
closed loop systems.
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Energy Efficiency
As can be seen from Figure 4 [3], there is a strong relationship between the (increase of) the
average annual oil price (blue line/right axis) and the number of GSHP systems installed per
year (bar diagram/left axis). The high demand for GSHP systems in 2006 has resulted in a
shortfall of drilling capacity in that year.
90
Quellen:
Ölpreis: www.tecson.de
Wärmepumpen: GtV, BWP
25.000
75
20.000
60
15.000
45
10.000
30
5.000
15
jährlicher Zuwachs an Wärmepumpen
2010
Jahr
2005
2000
1995
1990
1985
1980
1975
1970
1965
0
1960
0
durchschnittlicher Rohölpreis in
US$ / barrel
Installierte Wärmepumpen pro Jahr
30.000
Jahresdurchschnitt des Rohölpreises
Fig. 4. Correlation between GSHP’s installed per year and average crude oil price [3]
3.4 The Netherlands
In the Netherlands, UTES started to be implemented in the early eighties. In first instance the
objective was to store solar energy for space heating in winter. In the first project
(commissioned in 1983) vertical soil heat exchangers were used (BTES application). Given
the good experience with aquifer storage in later projects and the fact that in the Netherlands
aquifers can be found almost everywhere, in particular the application of ATES has been
further developed in the Netherlands. In 2005 the number of registered ATES projects was
537 [4]. In almost every major city a number of ATES projects are in operation. The aim of
most ATES projects is to store cold in winter for cooling in summer. In general, cooling is
direct, that is to say without using a chiller. In most projects the cooling capacity supplied
from storage lies between 500 kWt and 2000 kWt. This means that by applying cold storage
these projects economise on a large chiller [5].
Until 2000 most ATES applications were for individual buildings like offices and hospitals.
However, since about 2000 ATES also started to be applied as a central (collective) system
for a number of buildings, mixed developments and housing projects. At present several
utility companies are offering their clients to supply heating and cooling with ATES based
district heating and cooling systems, whereby the system is owned and managed by the utility.
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
600
2005
550
500
Agricultural
450
Industry
400
Housing
Commercial
350
Hospitals
300
Offices
250
2003
0%
10%
20%
30%
40%
50%
200
150
100
50
0
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
Total number
Annual number
Fig. 5. Number of ATES projects in the Netherlands and distribution per application area.
There are several BTES project realized in the Netherlands. Most of them are for collective
systems for housing projects. GSHP systems are mainly applied for heating or combined
heating and cooling of single family houses or small buildings.
For 2005 the estimated total number of installed heat pumps is between 30,000 and 31,000
[3]. About one third of these heat pumps are GSHP’s.
Photo 2: “Oostelijke Handelskade”, Amsterdam (NL). Collective heat pump and ATES system for heating and
cooling of mixed use development (passengers terminal, hotel, arts centre, offices and apartments).
321
Energy Efficiency
3.5 Spain
In Spain the GSHP and UTES technology are very new technologies. Since a few years
GSGP´s are starting to be implemented for heating and cooling. Several projects have been
realized, mainly for small scale residential buildings and most of them in Bask Country and
Catalonia. However, all over Spain a growing interest in renewable energies and the use of the
underground for exchange of thermal energy is developing. It is expected that within a few
years GSHP´s and UTES application will contribute to more efficient heating and cooling
systems in the Spanish building industry.
3.6 Sweden
Sweden probably shows the highest density of GSHP systems for single family homes in the
world: over 275.000 installed systems by the end of 2004. About 99% of the GSHP systems
are closed loop systems, mainly vertical U-tube systems (heating only) [6].
The number of large scale ground coupled heat pump systems was about 2.000 by the end of
2004. These systems range from 100 kW to more than 5 MW and can be subdivided as
following:
•
large scale GSHP systems, mainly for apartment blocks and small housing developments;
•
over 200 BTES systems, mainly for combined heating and cooling of commercial and
residential buildings;
•
over 50 ATES systems, mainly for combined heating and cooling of larger commercial
buildings and mixed developments.
The major obstacles for the implementation of ATES and BTES systems are lack of
awareness of the technologies, lack of experience with engineering and drilling companies,
and the complexity of the permit procedure (ATES systems).
3.7 United Kingdom
In the United Kingdom (UK) GSHP application started in the early 90’s. By 2005 there were
approximately 500 GSHP installations in operation across the UK. With an estimated increase
over the last two years of 60%, this results in approximately 800 GSHP installations in the
UK by 2007. The majority of these installations are mono-directional GSHP systems and are
small scale (<100 kW) residential applications. Over the last two years, however, there has
been an increase in interest for commercial and public building applications and various
GSHP systems >100 kW have been installed recently.
There is only one known ATES system installed to date in the UK. The system is for a
residential development in West London and has a storage capacity of 250 kW. The system
was installed in 2006 [7]. By the end of 2007, there were a number of larger scale (>500 kW)
ATES and BTES systems under development, and the level of interest in UTES application is
increasing. This is to a large extent attributable to recent sustainability requirements for larger
scale new developments and retrofits.
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Photo 3: “Westway Beacons”,
London (UK). Collective ATES
system for the heating and
cooling of 130 apartments.
So far, the heavy bias towards GSHP installations is due to the fact that the UTES technology
is only just starting to enter into the UK market and thus is regarded as a “new” technology.
The availability of suitable aquifers varies significantly in the UK and therefore certain areas
are suitable for ATES systems and others areas are more favourable to closed loop BTES
systems. London, the South East, Birmingham, Liverpool and East Anglia are examples of
areas where open loop GSHP or ATES systems are viable.
In the UK, the Environment Agency (EA) is the government body which regulates the
groundwater industry. Any larger scale open loop ground source heating and/or cooling
system has to go through the EA permitting procedure. The EA is becoming increasingly
worried about net heating or cooling effects on the ground of GSHP´s and is therefore in
favour of ground coupled systems like ATES and BTES, creating a thermal balance annually.
4
Conclusions
The application of GSHP’s , ATES and BTES is quite different for the various countries
considered in this paper. Some of these differences can be explained by climatological
conditions (combined heating and cooling is more favourable for the application than heating
only) and underground conditions (ATES versus BTES application). However, the presence
of clear energy efficiency targets for buildings and the availability of the GSHP and storage
technologies on the market seem to be the major explanation for these differences.
References
1. Desmedt, J. Hoes, H. Van Baal J.: Status of Underground Thermal Energy Storage in
Belgium. Ecostock 2006, Stockton, New Jersey (2006)
2. Sørensen, S.: Personal communication. EnOpSol, Hellerup (2007)
3. Reuβ, M.: Techniken der Oberflächennahen Geothermie. In: Oberflächennahen
Geothermie OTTI, Freising (2007) 19-21
4. Centraal Bureau voor de Statistiek (National Bureau of Statistics): Duurzame Energie in
Nederland 2005, Voorburg/Heerlen (2006)
5. Snijders, A.L: Lessons from 150 aquifer storage projects. Proceedings Terrastock,
Stuttgart, Germany (2000).
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Energy Efficiency
6. Andersson, O.: GSHP Systems in Sweden. International Working Conference
“Experience with Ground Source Heat Pumps”, SenterNovem Utrecht (2005)
7. Kennet, S: Trailblazing on the Westway. In: Building service journal 05/06, London
(2006) 38-40
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Section 5:
Industrial Presentations
325
Industrial Presentations
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Totally Integrated Building Automation
Devid Palčič¹
¹Robotina d.o.o., Sermin 7b, 6000 Koper, Slovenia
¹Cybrtoech, ltd., 14 Brinell Way, Harfreys Industrial Estate, Great Yarmouth,
Norfolk Nr31 0LU, United Kingdom
[email protected]; [email protected]
Abstract
Building automation is in spotlight, but in spite of this the area is still foggy. Many systems that should not be called Building
Automation are sold as Building Automation and in most cases customers do not get what they have hoped for. What
Building Automation really is? Where is it going? Can we count on solution, that will really add value to our buildings and
that will satisfy our needs, even the ones, we are not aware yet? We believe, that solution is already there and available. It is
reliable, efficient and totally integrated. As such it can offer solid basis for any kind of building.
Keywords
Building Automation, Ethernet, intelligent, Integra BM, Cybro.
1 Introduction
Modern buildings are mostly equipped with some kind of Building Automation, but the
definition of Building Automation is often too wide and unfortunately many of such buildings
can not be defined as automated buildings and they are very far away from being called
intelligent buildings. Users expectations, if not requirements, are higher. We all need
intelligent buildings. To become intelligent, building needs to be automated in the intelligent
way first. And to do so, some clear conditions must be met. All sensors and actuators must be
connected to the decision maker (usually a programmable or pre-programmed unit). Decision
makers have to be connected between themselves and they need a way to interact with
humans and computers. Furthermore such systems must be able to evolve as users and
technologies evolve and, everyone knows that building an electronic system which can be
usable and can evolve during next 25 years is a challenge by itself.
1.1 A Brief History of Integra BM
Generally Building Automation was historically developed with very different background.
Most solutions were result of an evolution of existing dedicated controller, which grew by
getting some communication skills. The typical result is a connected stand alone controller.
Such controllers are still widely used, the only real difference is, that communication ports are
getting more protocols and controllers can be integrated in different systems. Most of the
propriety controllers are connected in such way. This way was chosen by most manufactures
of complex controllers and equipment.
Others wanted to replace standard wiring in buildings. Their goal was to develop small
intelligent units, that are self sufficient, but able to communicate. Functionality once achieved
by wiring was now available by simple selection of parameter in the program. This was a
typical option for switch manufacturers. They could simply upgrade their existing range.
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Third group was ambitious. They have seen their future in building a story around
communication protocol. So they have tried to create a new philosophy. They have invented
profiles, defined variables and tried to make building automation very strict. They have even
succeeded entering into international standards. Their most powerful word is interoperability.
It worked well; they were the most successful.
Fourth way was an evolution of industrial automation controls. Industrial automation is based
on Programmable Logic Controllers (PLC) and Discrete Control Systems (DCS), all of them
completed with SCADA systems as Human to Machine Interface (HMI) and field bus systems
for effective replacement of Input and Output (IO) wiring.
Our group background is industrial automation, so the fourth way was obvious for us. From
the very beginning we have opted for almost revolutionary evolution of such concept. Our
PLC became distributed system with intelligent IO units. IO’s are still available in the form of
standard industrial IO units, but most of the available IO units are application or device
oriented products which can control very specific systems. CAN was selected as primary field
bus and Ethernet for communication between controllers and between controllers and other
products. As result we got an industrial standard system with extreme high reliability, high
speed and optimal price/performance ratio. Further development brought several solutions
know to other concepts into our system, so actually we have combined advantages of all four
approaches. And of course the same products can be used also for industrial automation.
This was enough to create very complex automated building, but still not enough to create an
intelligent building. To get to that point we had to provide better interaction with the outside
world, open our communication and define structure so to achieve a truly distributed control
system with embedded system know-how. The result is partially open system which allows
expert knowledge to on-line interact with it. First service servers (SS) are on-line and they
provide useful data to be used directly by Integra algorithms.
The missing part is coming in the near future. Tools to simplify and speed up the development
process with final goal: an automated system design tool.
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Fig. 1
2 Success Factors?
2.1
Introduction to Integra BM
Technically Integra BM consists of two very different Hardware levels. Each of them has
specific purpose and uses different communication method. Level 2 can freely communicate
with any device using Ethernet (computers, other units, operator panels, internet…).
Level 1: Cybro modules
Level 2: Cybro controllers
Hardware levels are complemented with several software tools that run on different platforms
and provide support to design and build systems, Human to Machine interface, connectivity
and all higher level functionality and intelligence.
Very important is the extensive solution library with built in expert solution know-how.
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Fig. 2.
Cybro Modules. Various modules are available and new products are being developed every
month, but all of them share same concept: small, intelligent, dedicated and cost effective.
They communicate between themselves and with level2 using CAN (control area network)
bus. CAN is reliable, fast and multi master protocol allowing relative freedom in system
topology. Every Cybro module has a unique NAD (network address) and no DIP switches are
needed for configuration. This is an enormous advantage, since the complete maintenance,
setup and programming can be performed remotely.
Cybro modules are always equipped with microprocessor. All of them can act as an intelligent
IO module when connected to Cybro controller, but most of them can also have local program
containing some specific solution (communication protocol, regulation algorithm…) or to
be used just in case of controller or communication failure.
Physically Cybro modules came in various forms: DIN rail, field module and embedded
module. Most of them will be soon available also in PCB form.
Actually more than 60 dedicated modules are available, covering every possible IO unit
(digital, analog, RTD, temperature, moisture, illumination, presence…), many communication
protocols (infrared, RS232, RS485, Ethernet, DSI, DALI, GSM, GPRS…), operator panels
(keypads, semi-graphics, touch screens, IR remote controller…), dedicated high function
modules (access control, inverter unit, RGB controller, fan-coil controller, hotel room
controller, light controller, switch unit, park sensor module…).
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New OEM modules can be developed in 4 to 6 weeks and can be ready for serial production
immediately.
Cybro Controllers. User program is normally running on Level 2 controllers. Cybro
controllers are always equipped with CAN interface to connect Cybro modules. In
addition to this Cybro controllers may have local inputs, outputs and communication
interfaces, with Ethernet being most important among them. Using Ethernet controller can be
programmed, monitored, remotely updated and managed over any kind of physical media
including Internet.
Cybro controller functions also as a gateway for Cybro modules. In this way modules are
available from virtually any place in the world. Unique NAD is used to guarantee reliable
access.
Physically Cybro controller can be hardware controller usually mounted in DIN rail housing,
but can also be a soft controller (SOFT PLC) running on various platforms.
Cybro Controllers are programmed in languages according to EN 61131-3. Application
generators and extensive libraries may reduce the need for programming, so most of the
standard systems can be simply configured. On the other hand full system power is available
to skilled programmers.
Fig. 3.
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2.2 Topology
CAN is used on level 1. Free topology (ring, star…) is allowed. Some rules must be followed
and termination resistors may be sometimes recommended. Special Integra cable is the best
option. Communication and power supply for Cybro modules share the same cable.
Alternatively other commercially available cables like EIB/KNX cable may be used with
some limitations in distance.
Fig. 4.
On Ethernet level all standard Ethernet devices are supported up to 100Mbps speed.
Depending on importance of the building system or subsystem high quality Ethernet active
equipment is suggested. Sometimes redundancy is the option of choice. Theoretically
controllers could be connected to office network, but this option should only be used in
limited cases.
2.3 Human to Machine Interface
Buildings must interact with users and for this various HMI are used. We need various ways
to tell to our building what do we want. From simple push button to computer interface,
HMI’s have to provide direct control, parameter setup, full user control and complex system
setup.
HMI Classification. We have divided HMI’s in basically two levels: sometimes border
between them may not be absolutely clear, but as a general rule level 1 is used for direct
control and parameter setup, while level 2 is used for higher functions.
Level 1 HMI’s are mostly Cybro level 1 modules (push buttons, operator panels, small touch
screens, IR remote controllers…). They provide essential information an allow user to start or
stop some action, set some parameters and perform some other tasks. Level 1 module may use
CAN and sometimes Ethernet interface. Some modules with dual interfaces are considered.
Cybro modules are available as Hardware and software package to allow easy and efficient
system configuration.
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Fig. 6.
On level 2 we can find computers in various forms. Software solutions which run on such
computers are essentially divided in HMI software for “ordinary” users and in management
stations for “skilled” users. Ordinary users need easy to use, strait forward HMI, while skilled
users (maintenance, setup, facility management) may prefer power and flexibility to
simplicity. Ethernet is a communication interface on Level 2 HMI. Most products offered are
software solution. Hardware is only provided to simplify choice, to guarantee compatibility
and to unify design.
HMI Design. Many times HMI appearance is the most important parameter that determines
final choice, therefore great care has to be dedicated to this issue.
The mostly used HMI is still pushbutton. Integra BM allows integration of every pushbutton
found on the market. Just add SW-W module and pushbutton will be transformed in
intelligent pushbutton, not to mention, that also LED can be controlled from user program.
For other types of HMI customization is offered as standard. Operator panels can bear your
logo, frames can me made of different material and there is wide choice of colors. Our
engineers can work together with customer to fulfill their specific needs.
New Technologies. Human acceptance of new technologies is changing extremely fast, so
new HMI’s are coming into consideration. Mobile phones or PDA’s are the most probable
candidates for universal HMI. Actually we can already use them, but in future we expect more
efficient solutions.
Our approach uses dedicated software solutions called “BM gadgets”. A gadget is a small
program that can run on PC or other platform (windows CE, Linux, Windows mobile).
Gadget also contains Cybro program code, so the complete functionality comes with it.
Various gadgets are available and they are usually enough to fulfill most requirements of most
users. New gadgets can be easily developed and functionality can be extended.
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Fig. 7.
Gadget is not only HMI, but can also add functionality to the system. User does not need any
programming shills and the whole setup process can be completely automatic, just like plug
and play building automation.
2.4 Intelligence
Building must be wired and automated to be candidate for starting the process to turn it into
intelligent building. We understand building intelligence as ability to adapt to various
situations, to learn and improve and to predict and modify its reactions based on predictions.
This inevitably means that expert systems and specific knowledge must be used.
Actual Building Automation hardware and software was designed for reliable operation in
standard conditions and it does not include specific solutions that meet the above mentioned
criteria.
Furthermore adding intelligence directly into Building Automation System would drastically
increase complexity (amount of code) and with increase in complexity probability of
malfunction also increases.
Solution was found in external intelligence which can interact with algorithms inside Building
Automation. We are creating specification for so called Service Servers (SS) and Agent
Servers (AS). Such servers are independent programs running on computers, most probably
connected to internet and offering some information to Building Automation systems (SS) or
performing direct actions in Building Automation Systems (AS).
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For example we have created an SS which provides information about whether forecast in the
format directly usable for correction of a heating controller parameter list. As a result a floor
heating system, which is too slow to use only actual outside temperature data as measured
temperature, can use forecasted parameters for fine tuning. As a result we got better comfort
and we saved energy.
An AS could for example look for best priced electrical energy and dynamically and
automatically switch users to the best provider. This may not be of great help if one apartment
is managed, but imagine what savings we are talking about if we consider a whole city or
even more.
3 Future
Future belongs to automated intelligent buildings and infrastructure. Technically we believe
in an evolution of actual hardware and in fast expansion of our intelligence concept on
software side. Furthermore design and setup of an intelligent building will become easier and
more automated. Users will still prefer very reliable basic functionality and fancy add-ons, so
our buildings will most probably go the way cars went in last 20 years: improving
functionality, comfort and safety.
Most of property protocols to external world will be replaced with open protocols, most
probably with TCP/IP or some other internet protocol. Field buses will replace standard
wiring. Many of them will offer enough reliability and performance to stay in life for next
years.
The real revolution will be in opening our buildings to the external world.
We believe that independent SS and AS will offer free or paid services and such expert
knowledge will be physically separated from Building Automation itself, but it will interact
with them and offer advantages to those who will opt for it.
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High Energy Efficiency in Intelligent Housing Built through
Integrated and Industrialised Processes
Ana Iglesias González1
1
Director, Residential Innovation Projects of the Municipal Housing
and Land Authority of Madrid (EMVS) [email protected] www.emvs.es
Abstract
For several years, the Municipal Housing and Land Authority of Madrid (E.M.V.S.) has been regularly
incorporating Highly Energy Efficient facilities to housing developments. This presentation is focused on
one of the action courses to be followed by the E.M.V.S., within the sphere of the I3CON Project, which
considering the gathered experience during the last years, it is believed as the natural next step towards the
evolution of the sustainability assigned criteria.
Therefore, this experience’s aims will frame construction industry on a sustainable prospect and will
provide integrated processes industrially manufactured, as well as intelligent construction systems, for which
we will use, among others, the usual technologies used by the E.M.V.S. to which we will refer later, control
systems distributed with incorporated sensors, wireless connections, user environment interfaces and
autonomous controllers.
1
Introduction
In the E.M.V.S., we make an initial approach from the view of sustainability for each one
of our housing developments: “the best facility we can build in edification is the one that is
not necessary to build”, meaning that the less pollutant energy is the one that is not necessary
to use.
With this premise, we distinguish between two aspects on the construction of our buildings,
on one hand, making the building need as little energy as possible, and on the other, making
sure such minimum needed energy is sent as efficiently as possible.
The programme we are working on, not only will amply fulfil the described premises, but
also will be reproducible, and intends to research and develop new implementing and
execution processes with results such as a 50% reduction of costs, a 70% reduction on
execution schedule, and a 90% reduction of industrial accidents. We will work on this
programme with open and pre-manufactured industrialized constructive systems, mobile
industries with component production at the same construction site and with the participation
of the future user from the very beginning, all this managed through powerful design
computer tools, configuration, personalization, intelligent joining together of working
materials, etc. developed specifically during each project.
The final purpose will be to demonstrate the construction of flexible buildings, reduction of
the developing schedule, maximum planning, personalizing the technology of the dwelling
and user satisfaction, with direct consequences over recycling, material efficiency and
building life cycle.
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2
Basic Criteria That Feed the Programme
This intends to overcome the inertia of usual construction, through a commitment for
modulation, industrialization and optimization of the energetic capacity.
Dwellings will count on an especially cared-for construction, based on North and South
orientated buildings, with crossed ventilation and isolations above the requirements of the
C.T.E. (Technical Building Code), while incorporating the demanded air quality for an
adequate living quality. All this, favouring the conditions of bioclimatic passive architecture
and the achieved experiences on the incorporation of elements such as solar chimneys,
materials of phase-change PCM, evapotranspiration, etc.
Fig. 1. Outer solar chimneys, building developed by EMVS, San Fermín St. plot 12, North area outer air inlet.
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Fig. 2. Inner solar chimneys
constructive detail, “Sunrise” building
developed by EMVS, North area outer air
inlet.
Fig. 3. Energy production station with phase-change
materials in water-heating, cold water and tank circuits.
Fig.5. Phase-change materials applied on outer
layers for the better use of thermal inertia.
Fig. 4. Inner solar chimneys
constructive details, “Regen Link”
EMVS development, indirect air inlet of
sanitary chamber.
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Fig. 6. Phase-change materials applied on Trombe walls.
3
Industrialization and Prefabrication of the Facilities
All dwelling facilities such as water, electricity, telecommunications, air conditioning, etc.,
will be gathered together in technical units.
All the building facilities will be made at the assembly shop, being assembled at the
construction site as prefabricated parts. The greater complexity for prefabrication systems lies
in the Hot water (DHW) heating and collection production area. We will pay special attention
to the vertical technical centre, where individual energy and hot water measuring systems will
be placed for every user.
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Fig. 7. Standardized prefabrication of
power station.
Fig. 8. Standardized prefabrication of power station.
Fig. 9. Standardized prefabrication of hot water tank station.
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Fig. 10. Standardized prefabricated cabinets for temperature control, and for control of users’ energy and hot
water readings with tour, three and two units.
4
Energy Efficiency of the Building
Energy efficiency of the programme’s buildings is a mainstay of their design and
conception, always taking into account that the winter regime will determine their future
energy invoice.
Thus, and in a short and summarized way, the most relevant aspects that will allow to fairly
classify these buildings as holders of an elevated bioclimatic nature are stated below, with
Highly Energy Efficient facilities, extensively tested for several years in the housing buildings
developed by the E.M.V.S. This is why, and as indicated before, in this programme we intend
to take the next natural step, that is, The Prefabrication of Components and the
Systematization of Processes.
To systematize the execution of what we now call Heating and Water-Heating Facilities of
High Energy Efficiency with Thermal Solar Energy, of Centralized Production and
Individualized Consumption, the E.M.V.S. has drawn up a Technical Specification List
which, along with the hydraulic diagrams and recommendatory assemblies, gives architects,
engineers, construction companies, fitters, energy managers, etc. an exact knowledge from the
basic project phase, a defined system in each housing development.
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Fig. 11. EMVS Technical Specification List for housing developments of more than twenty-five dwellings.
Fig. 12. Hydraulic diagram recommended for EMVS housing development of more than twenty-five
dwellings.
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5
Basic Concepts to Be Defined On the Prefabrication of Highly Efficient
Energy Facilities
ƒ
Design criteria
ƒ
Minimum annual seasonal capacity
ƒ
Technology to be used
ƒ
Demanded renewable energies
ƒ
Energy savings to be achieved
ƒ
Reduction of pollutant emissions
ƒ
Energy management.
5.1
(Rea)
Design Criteria
The system is conceived as a heating and hot water system for individual consumption with
centralized production, working with several temperatures and not using mixtures inside the
thermal production centre.
5.2
Minimum Annual Seasonal Capacity (Rea)
The minimum capacity demanded is 140% over P.C.I. (lowest calorific power of natural
gas).
The annual seasonal capacity of the whole is the ratio existing in the course of a year of
operation, between the useful thermal energy sent to the building, and the used primary
energy from fossil fuel.
Useful Energy
Rea =
Primary Energy
5.3
Technology to Be Used
In combustion: Condensation and low temperature boiler burners will modulate with a
25% minimum, and this modulation will be achieved through outer signals of
telemanagement.
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Fig. 13. Modulant burner from 25% of the
power connected to condensation boiler.
Fig. 14. Radial flame burner of low nitric oxides
emission (NOx).
Fig. 16. Thermal production centre with lowtemperature generators.
Fig. 15. Condensation boiler with vertical
condensed collector.
In regulation: This will be achieved automatically, through a programmable and
telemanaged electronic switchboard, fitted with communication card and modem, controlled
both by the energy manager and the EMVS.
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Fig. 17. Telemanagement screen with realtime emission data.
Fig. 18. Telemanagement and monitoring centre.
Fig. 19. Electric and control board with
electronic switchboard of telemanaged
regulation.
Fig. 20. Telemanagement applications.
In measuring and thermal centre control: energy meters for heating, DHW and thermal
solar energy will be placed in the boiler room
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Energy meters
Fig. 21. Thermal centre with energy meters.
In measuring and dwelling control: For heating, mechanized two-way valves and energy
meters are fitted in each dwelling, set with the environment thermostat usually installed in the
living-room of the dwellings. For hot water, volumetric meters are set in each dwelling.
HEATING
DRILL-CARRIER
VALVE
ACS
VOLUMETRIC
METER
TWO WAYS
VALVE
BIDIRECTIONAL
HEATING
OUTWARD DRILL
ANTI-RETURN
VALVE
A.C.S.
OUTWA
RD
HEATING
RETURN
FILTER
ELECTRON
IC BOX’S
BRACKETS
ENERGY
METER
Fig. 23. Control and energy measuring Unit.
Fig. 22. User energy meter.
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HEATING
RETURN DRILL
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In accelerator pumps: Twin pumps will be set in the circuits, in order to stop the system
in case of damage, with variable speed in the heating circuit and in the recirculation circuits of
the boilers.
Fig. 24. Variable speed twin pumps.
In radiators: these will be measured with a temperature differential of 40ºC between the
average temperature of the radiator and the environmental temperature of the room (input to
radiators 68ºC, back to boiler 56ºC, with calculation outer temperature of -3,7ºC, and inner
design temperature of 22ºC)
Fig. 25. Low temperature radiators.
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In isolation: Thicknesses prescribed in current regulations will be increased by 10 mm;
likewise all the valves will be isolated as well as pump bodies, bridles, energy meters and any
other hydraulic element of the installation. It will be finished in 0,6 mm thick aluminium
sheet.
Fig. 26. Thermal Isolation finished with aluminium sheet.
In hot water: Thermal solar panels are to cover at least 75% of the hot water production,
along with pre-heating of cold water filling.
Fig. 27. Vacuum tube on façade.
Fig. 28. Flat solar panels on the roof.
In heating: Supporting this service with solar energy even at night when there is no sun,
from the surplus energy of the DHW, that is, once the water heating necessities are covered,
the accumulated energy will be diverted for heating production.
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Fig. 29. Flat solar panels on the roof.
In electrical household appliances: Thermal solar energy for water heating for
conventional (not bi-thermal) washing machines and dishwashers through the fitting of
mixing valves at their feeding point.
In security: A heat cooler element will exist in the thermal solar energy circuit, to prevent
its temperature to rise above 110ºC. Likewise, mixing valves will be installed at the hot water
exit to prevent overheating of consumption water.
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Fig. 30. Heat cooler element to prevent steam production on solar circuit.
6
Energy Savings and Emission Reductions Planned In the Programme
Annual seasonal capacities (REA) estimated for this programme, will be higher than the
ones currently achieved in buildings developed by E.M.V.S. and that have been occupied for
several years, in which this energy generation system has been installed.
This performance will be monitored and permanently measured in the installed energy
meters, and will be around 140%, so that the energy savings just derived from the facilities’
energy efficiency, not counting minimum building necessities that will be detailed on their
appropriate description and energetic certification documents as prescribed on the new CTE
(Technical Code for Edification), will be as pointed out on the following charts:
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720
126,82
CO2 Emissions
(Tm/year)
60,35
Costs per dwelling
exploitation
(€/house/year)
House gas
consumption
(m3/house/year)
Primary energy
consumption of
building
(MWh/house/year)
Individual boiler
without solar in the
same building, with
the same
contribution and
period
98,83
444
345
86
67
Annual Seasonal
capacity (%)
140
Individual boiler with
solar in the same
building, with the
same contribution
and period
900
850
800
750
700
650
600
550
500
450
400
350
300
250
200
150
100
50
0
460
565
618
725
EMVS Sytem in a 80
dwelling building,
with a 486,10 mWh
contribution from
28Jan07 to 28Jan08
727
933
Chart 1. Comparative between EMVS system and individual (with and without solar contribution) boiler
system.
200
73
54
Chart 2. Comparative between EMVS system and individual (with and without solar contribution) boiler
system, in a year.
150
100
50
-66,47
-260
-158
352
-50
-100
-150
-200
-250
-300
-350
-489
o
-400
-450
CO2 Emissions
(Tm/year)
-500
Costs per dwelling
exploitation
(€/house/year)
House gas
consumption
(m3/house/year)
Primary energy
consumption of
building
(MWh/house/year)
-380
-283
-220
C omparative between EMVS
system and individual nosolar boiler in one year
Annual seasonal
capacity
C omparative between EMVS
system and individual solar
boiler system in one year
-38,48
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
6.1
Extrapolation of Programme Results to 10.000 Houses during 10 Working Years
The following chart represents energy and emission savings that should be achieved in
10.000 dwellings during 10 working years, comparing the system used by the EMVS to
conventional facilities
300.000
275.000
250.000
225.000
200.000
175.000
150.000
125.000
100.000
75.000
50.000
25.000
0
CO2 Emission reduction in TM
48.100
Exploitation costs savings in
thousand euros
15.800
Gas consumption saving in
thousand m3
Energy consumption saving
of primary energy in MWh
28.300
275.000
Chart 3. Savings derived from the use of the EMVS system.
From the previous chart we can infer that, given that an average dwelling in Madrid
disperses about 4Kwh of thermal energy in winter, with the achieved saving in 10.000 houses
during 10 years with these systems, we could supply with heating to almost 48.000 dwellings
all in one winter.
7
Energy Management
Optimized energy management, starts once the facilities are finished; the Energy
Manager, which is usually the installation fitting Company, will assume the responsibility of
maintenance and exploitation of these facilities, 24 hours a day and 365 days a year, assuming
to be in charge of:
Fuel needed to feed heating and hot water to each dwelling, even those at the top; along
with registrations and deposits with the distribution companies.
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Industrial Presentations
Fig. 31. Natural gas meter.
Cold water needed for hot water consumption, as well as the necessary water for filling
the circuits, and the supply of antifreeze for the thermal solar energy circuit.
.
Fig. 32. Water meters
in Battery.
Fig. 33. Water meter.
Telemanagement, being in charge of telephone costs of the service.
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Fig. 34. Water meter with
impulses input.
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Fig. 35. Electronic regulation switchboard with communication card and modem.
Meter reading and invoicing, carried out monthly by the energy manager for each user of
the housing development, individually, according to consumption.
DATA BUS
CONNECTION
ELETRONIC
CONNECTION PILOT
DWELLING
THERMOSTAT
CONNECTION
TWO-WAYS VALVE
CONNECTION
230 V SUPPLY
ACS METER
CONNECTION
TRANSFORMER
ENERGY METER
CONNECTION
Fig. 36. Electronics for temperature control and energy and hot water remote reading meters.
The guarantee, through which the energy manager will repair or replace, at his charge, all
the damaged or obsolete elements and units of the communal facility (boilers, burners, storage
batteries, pumps, solar panels, pipes, etc.) during the life of the signed agreement
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8
Intelligent Building Control and Monitoring
For the achievement of an intelligent building control, as indicated before, control systems
will be used, distributed with incorporated sensors, wireless connections, user interfaces and
autonomous controllers.
These systems will be designed with standardized and open communication protocols, in
order to increase unit durability, which means that in the event of technologic evolution
and/or material replacement they will be replaced individually, without having to forcefully
change the whole unit or used software. These systems could be, according to the data
obtained by the sensor, proportionally regulated (DALI Control) or all-none regulated.
On the application field of these integrated management systems, we can emphasize:
Air quality sensors, which will measure quality conditions, both of the outer and inner air
of the dwellings, and which will renew building air according to established parameters on the
installed software.
These sensors will control and operate basically on the air volume, temperature variations,
relative humidity, etc., and this way will be able to increase comfort and therefore, life quality
of the users.
Fig. 37. Air quality meter.
Luminosity sensors, that will control and operate on the lighting systems both communal
and private, according to established parameters and obtained data from taken measurements.
They will be able to send signals and modify from window blinds and curtains, to electronic
ballasts of the installed lighting, thus modifying unused areas or improving the lighting in the
currently used area.
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Fig. 38. Luminosity sensor.
Wind sensors, modifying openings for ventilation and window positioning, housing
conditioning and air quality, thus improving the users’ comfort this way.
Fig. 39. Wind sensor with individual reading per user.
Rain sensors, operating over watering and/or windows
Fig. 40. Outer rain sensor.
Sensors in windows, operating over housing conditioning.
Movement detectors interacting with lighting and conditioning
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Industrial Presentations
Fig. 41. Presence and light detector.
Multiparameter meters, installed in the dwellings and/or communal areas, so that every
user may know in real time his consumptions and may interact with his energetic spending,
water, air, etc.
Fig. 42. Individual multiparameter meters for users.
Electric signals with alarm control inlet, so that in case of need or emergency, it is
possible to operate automatically over electric, hydraulic and/or alarm circuits.
Different building monitoring will be permanently interacting and will be achieved through
wireless nets, which will be designed to be controlled from a single checkpoint, either in situ
or remote, by an energy manager or by the developer where appropriate.
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
Fig. 43. Several screens from the central checkpoint.
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Industrial Presentations
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The 1st International Conference On Industrialised, Integrated, Intelligent Construction. 14-16 May 2008
The Multi Heat System
Sergio Palombi, Alberto Zerbinato
ICI CALDAIE S.A., Spain
[email protected]
The distributed generation model involves installing a large number of high-performance micro-plants for cogeneration
that satisfy a significant portion of energy consumption (electrical, heating and air conditioning) for domestic, commercial
and service sector. The answer lies in distributing heat through thermal satellite modules which combine versatility and
autonomy of independent boilers with the simple operations and high performance of centralised production. The thermal
satellite module receives the primary fluid from the heat plant and quantifies all the energy that enters in a single apartment,
thus allowing each user to manage his own consumption and expenditure. The electronic control panel allows each single
module to monitorize and adjust. The application of the system comprising condensation boilers (today and fuel cell
systems in the future), renewable energy (solar panels) and meter modules is the ideal solution for modern installations
with centralised production.
Distributed Generation
The energy needs of homes, apartment buildings and stores
– which are fundamentally electricity, heat and cold – have
been traditionally met through the separate supply of electric
and thermal energy. The traditional model used to meet these
needs involves generating electricity in large thermoelectric
power plants, which are distant from the metropolitan user
basin, and subsequently transferring it through a network of
distribution to single users. Thermal energy, on the other hand,
is generated by the single user (whether a home or apartment
building) by means of combustion heating systems. Last,
cooling energy is generated by means of compression systems
that are powered by the same electricity system. This triedand-tested model has several disadvantages, first among these
a low thermodynamic efficiency overall (if all the three needs
above are considered as energy outputs), as well as polluting emissions that are by no means negligible and the
need for an efficient electricity distribution network, which is expensive in terms of investments and operating
costs. For the end user, all this leads to rather high energy costs. The classic alternative to the model described
above is large districtheating networks powered by relatively large cogeneration plants, that combine electricity
production with heat and/or cold generation in a centralised manner. In this way, some of the problems above are
eliminated, but the problem of emissions remains as does the need for a double network, with its related costs for
the thermal energy and electric power distribution. Over recent years, technology is giving greater importance to
the socalled “distributed generation” of electricity, cold and heat in a territory. The result is major changes to the
role of the existing electricity network as well as to combustion/compression systems for heat/cold production.
The distributed generation model involves installing a large number of highperformance micro-plants for cogeneration that satisfy a significant portion of
energy consumption (electrical, heating and air conditioning) for the domestic,
commercial and service sector. By combining the well-noted thermodynamic
benefits of cogeneration with the expected highperformance levels of the most
promising micro-generation systems, this would lead to a more rational use of
energy resources and would drastically simplify the infrastructures required to
carry the energy.
An example of heat distribution system
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Industrial Presentations
How can units be adapted for this new
technology?
The answer lies in distributing heat through thermal
satellite modules which are a response to the recent demand
for products that can combine the versatility and autonomy of
independent boilers with the simple operations and high
performance of centralised production. The thermal satellite
module receives the primary fluid from the heat plant and
quantifies all the energy that enters in a single apartment, thus
allowing each user to manage his own consumption and his
own expenditure. Plumbing and subsequent adjustment allow
heat to be produced for heating and hot domestic water
production. The electronic control panel allows each single
module to monitored and adjusted. The modules are available
in the recessed version and for outdoors, fitted with calorifier
or instant response for domestic hot water and distribution of cooled water. In the more complex versions, the
modules can also manage units with different temperature levels (mixed floor systems) and summer/winter
inversion for summer cooling.
The application of the system comprising
condensation boilers (today and fuel cell systems
in the future) and meter modules is the ideal
solution for modern apartment buildings, offices,
public buildings, and other buildings by
combining the need for independent use with
centralised production.
Radiax box module
362
Department of Civil & Building Engineering
Loughborough University
Leicestershire LE11 3TU
United Kingdom
T: +44 (0)1509 228741
F: +44 (0)1509 223981
E: [email protected]
URL: www.i3con.org
ISBN: 978 1 897911 32 7