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The EWZ building
The EWZ
building
Presentation
of the building
The design
issue
The building
concept
The winter
monitoring
The summer
monitoring
Major
findings
More
information...
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Project presentation (1...)
The EWZ
building
Presentation
of the building

The EWZ building was completed in 1994.

The building is situated in the northern part of Zurich in an urban area.

It is a five storey triangular shaped building, with two sides facing busy
roads in a congested urban area.

It is designed to protect the occupants from noise and air pollution.
Major
findings
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
The façades provide a noise barrier and four atria are included (two on
the north-side and two on the south-side) to provide maximum daylighting
and natural ventilation.
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
Thanks to its massive construction the building has a high thermal mass
The design
issue
The building
concept
The winter
monitoring
The summer
monitoring
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Project presentation (2...)
The EWZ
building
Presentation
of the building
The design
issue
The building
concept
The winter
monitoring
The summer
monitoring
Major
findings
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
It is a five storey triangular
shaped building, with two
sides facing busy roads in a
congested urban area.
Project presentation (3|)
The EWZ
building
Presentation
of the building
The design
issue
The building
concept
The winter
monitoring
The summer
monitoring
Major
findings
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information...
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Naturally ventilated
offices
Mechanically
ventilated
offices
Mechanically
ventilated atria
The design issue (1...)
The EWZ
building
Presentation
of the building

A two step hybrid ventilation concept was chosen to meet
energy and comfort demands:
 The four atria are mechanically ventilated during the day, but
provide manual window access to the surrounding offices which
are naturally ventilated.
 At night time the atria and the offices are naturally ventilated.

Decentralised ventilation units are used to reduce ductwork and
energy use.

The main target of this project was to design an energy efficient
multi-use building, both in construction and in use.

After completion of the building, the aim is to achieve further energy
savings during operation together with good indoor environment.
The design
issue
The building
concept
The winter
monitoring
The summer
monitoring
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findings
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The design issue (2|)
The EWZ
building
Presentation
of the building
The design
issue
The building
concept
The winter
monitoring
The summer
monitoring
Major
findings
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The building concept (1...)
ventilation strategy during summer
The EWZ
building
Presentation
of the building

… for the Atria:

During working hours:
Mechanical ventilation with
heat recovery and central
cooling.

At night: Natural ventilation by
window opening in the atria.
The summer
monitoring
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findings
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Offices
The winter
monitoring
Atria
The building
concept
Offices
The design
issue

… for the Offices :

Natural ventilation by manual
opening the windows facing
the atria.
The building concept (2...)
low energy use in winter time
The EWZ
building
Presentation
of the building
Fresh Air

The design
issue
The building
concept
The winter
monitoring
The summer
monitoring

Major
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The mechanical
ventilation system
is equipped with a
central heat
recovery unit to
reduce the energy
losses during the
heating season.
Moreover, the
ventilation is
turned off outside
office hours
Exhaust Air
Heat Recovery Unit
Supply Air
The building concept (3...)
overall strategy for summer comfort
The EWZ
building
Presentation
of the building

Ice stack is loaded during the night to cool during the day. The atria are
then ventilated, with a projected air exchange rate of 5 h-1 (pre-cooled air
at 16 to 17°C). To properly mix the air in the atria ventilators are installed.

In addition night cooling is applied by automatically opening the top
windows in the atria.

To reduce solar impact there are motorised shading devices (external
screens) on the side walls and atria roofs.

There is no active cooling in the offices !
The design
issue
The building
concept
The winter
monitoring
The summer
monitoring
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(Schematic - see next slide…)
The building concept (4...)
overall strategy for summer comfort
The EWZ
building
Presentation
of the building
Night
Day
The design
issue
The building
concept
The winter
monitoring
The summer
monitoring
Major
findings
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External
screens
Night
Cooling
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Ice stack
load
Mixing
Fans
Cooled Air
(Outside air is
pre-cooled by
the Ice stack
load: 16 to
17°C)
The building concept (5|)

The ventilation concept
was chosen to meet
comfort demands.

Concept: The atria is
mechanically ventilated
and provides manual
window access to the
surrounding offices which
are naturally ventilated.

Control: The air change
rate in the office is
chosen by the users as
they wish.
The design
issue
The building
concept
The winter
monitoring
The summer
monitoring
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findings
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Atria
The EWZ
building
Presentation
of the building
Offices
indoor air quality during office hours
Monitoring set-up
The EWZ
building
Presentation
of the building

The design
issue
The building
concept
Continuous measurements of carbon dioxide (CO2 ) / ventilation rate /
temperature / humidity / indoor air velocity (in the offices)
were made over one week periods during
 February 1997,
 July 1997,
in

The winter
monitoring

The summer
monitoring

Major
findings
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

.
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atrium 2 (right side of the south façade of the building)
three cellular offices on the first, second fourth floor of the atrium 2 (fully
monitored)
atrium 1 (left side of the south façade of the building)
three cellular offices on the first, second fourth floor of the atrium 2 (only
temperature)
The following offices were considered as representative:
 for winter: a cellular office on the second floor surrounding atrium 2
 for summer: a cellular office on the first floor surrounding atrium 2
The monitoring results of these offices are shown in the following charts
Winter monitoring (1...)
typical winter day - monitoring results
The EWZ
building
Presentation
of the building
The winter
monitoring
The summer
monitoring
Major
findings
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Slight overheating in offices due to problems with
automatic control of the shading devices
1000
30
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25
800
20
600
15
10
400
5
200
0
12
15
18
21
00
03
06
09
12
15
18
21
00
03
06
09
12
15
18
21
00
-5
0
07-09.02.1997
Indoor Temp.- office [°C]
Air Change - office [1/h]
Atrium Temp. [°C]
Carbon Dioxide [ppm]
Outside Temp. [°C]
Carbon dioxide
The building
concept
1200
35
Indoor and outside temp
air change rate
The design
issue
40
Winter monitoring (2...)
typical winter day - monitoring results
The EWZ
building
Presentation
of the building
The winter
monitoring
The summer
monitoring
Good IAQ: low CO2 concentration during
office hours (far below 1200 ppm)
1000
30
Major
findings
More
information...
25
800
20
600
15
10
400
5
200
0
12
15
18
21
00
03
06
09
12
15
18
21
00
03
06
09
12
15
18
21
00
-5
0
07-09.02.1997
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Indoor Temp.- office [°C]
Air Change - office [1/h]
Atrium Temp. [°C]
Carbon Dioxide [ppm]
Outside Temp. [°C]
Carbon dioxide
The building
concept
1200
35
Indoor and outside temp
air change rate
The design
issue
40
Winter monitoring (3|)
typical winter day - monitoring results
The EWZ
building
Presentation
of the building
The winter
monitoring
The summer
monitoring
Low air change rate is sufficient: good air quality
1000
30
Major
findings
More
information...
25
800
20
600
15
10
400
5
200
0
12
15
18
21
00
03
06
09
12
15
18
21
00
03
06
09
12
15
18
21
00
-5
0
07-09.02.1997
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Indoor Temp.- office [°C]
Air Change - office [1/h]
Atrium Temp. [°C]
Carbon Dioxide [ppm]
Outside Temp. [°C]
Carbon dioxide
The building
concept
1200
35
Indoor and outside temp
air change rate
The design
issue
40
Summer monitoring (1...)
typical summer day - monitoring results
The EWZ
building
Presentation
of the building
40
The design
issue
30
The winter
monitoring
The summer
monitoring
Indoor and outside temp
air change rate
The building
concept
35
Major
findings
More
information...
25
20
15
Good thermal comfort in office: Tint = 23°C while Text goes to 33°C:
Remark: This results is partially the result of active cooling in the
atrium
10
5
0
12
15
18
21
00
03
06
09
12
15
18
21
00
03
06
09
12
15
18
21
00
23-25.07.1997
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Indoor Temp. [°C]
Outside Temp. [°C]
Atrium Temp. [°C]
Summer monitoring (2...)
typical summer day - monitoring results
The EWZ
building
Presentation
of the building
The winter
monitoring
The summer
monitoring
Good IAQ: low CO2 concentration during
office hours (far below 1200 ppm)
1000
30
Major
findings
More
information...
25
800
20
600
15
10
400
5
200
0
12
15
18
21
00
03
06
09
12
15
18
21
00
03
-5
06
09
12
15
18
21
00
0
23-25.07.1997
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Indoor Temp.- office [°C]
Air Change - office [1/h]
Atrium Temp. [°C]
Carbon Dioxide [ppm]
Outside Temp. [°C]
Carbon dioxide
The building
concept
1200
35
Indoor and outside temp
air change rate
The design
issue
40
Summer monitoring (3|)
typical summer day - monitoring results
The building
concept
The winter
monitoring
The summer
monitoring
1200
Air change rates are
sufficient  good IAQ
35
Major
findings
More
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1000
However no ventilation
during the night to cool the
office: window is closed
30
Indoor and outside temp
air change rate
The design
issue
40
25
800
20
600
15
10
400
5
200
0
12
15
18
21
00
03
06
09
12
15
18
21
00
03
-5
06
09
12
15
18
21
00
0
23-25.07.1997
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Indoor Temp.- office [°C]
Air Change - office [1/h]
Atrium Temp. [°C]
Carbon Dioxide [ppm]
Outside Temp. [°C]
Carbon dioxide
The EWZ
building
Presentation
of the building
Major findings (1...)
The EWZ
building
Presentation
of the building

The design
issue
The building
concept

The winter
monitoring
Night Cooling of the atria:

Thanks to the architecture the stack effect in the atria can be considered to
provide a sufficiently strong force for natural ventilation;

On the other hand a re-evaluation of the dimensions of the openings could
increase night ventilation resulting in a better natural night cooling.
Night Cooling of the offices - Barriers

Night cooling in the atria only takes place if atria windows are open. The atria
windows are in this case automatically open if outside temperature is three
degrees lower than the air temperature in the atria (this a typical strategy for
mechanical night cooling). For natural night cooling the atria windows should
automatically open if outside temperature is lower than the air temperature in
the atria

Night cooling in the offices only takes place if the office windows have been left
open after the end of the working days. Closed office windows and doors form
a large obstruction for the natural night cooling. The best night cooling
efficiency is achieved by cross ventilation through window and door.
The summer
monitoring
Major
findings
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Major findings (2...)
The EWZ
building
Presentation
of the building

The design
issue
The building
concept
Shading devices:

In the winter, the shading devices , which close automatically, did
not close at the right time. Therefore offices are sometimes lightly
overheated and illuminated with too much direct sun light.

The automatically shading devices in summer achieved the
expected aims. The thermal comfort in summertime is optimal
(remark: in summer active cooling is used in the atria).
The winter
monitoring
The summer
monitoring
Major
findings
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
The Indoor Air Quality is always acceptable

Occupant Reactions:
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
The occupants are very satisfied with the building.One of the
main reasons is that they appreciate being able to open the
windows.
Major findings (3|)
The EWZ
building
Presentation
of the building

In General:

The design
issue
The EWZ building is a good example of a pragmatic approach.
The hybrid concept combines active cooling and passive
elements like night cooling and shading devices. The concept
provides high quality indoor comfort at any external condition.
The building
concept
The winter
monitoring

The summer
monitoring
Major
findings
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Energy consumption:

The EWZ building can be considered as a building with a rather
low energy consumption. A further reduction of the energy
consumption can be achieved by an optimisation of the heating
level in winter and the electricity consumption for the cooling and
for the mechanical ventilation.
More information...
The EWZ
building
Presentation
of the building
The design
issue
The building
concept
The winter
monitoring
The summer
monitoring
Find more information on the PROBE building in the following documents:
\Reports \Monitoring Reports \Summary Reports\ch2summ.pdf
 global presentation of the buildings (4p./building)
 contents: building description - ventilation strategy and technology winter and summer monitoring results - conclusions
\Reports \Monitoring Reports \Detailed Reports\ch2det.pdf
 detailed reports of all 19 monitoring campaigns (20p./campaign)
 contents: monitoring set up - analysis of results - conclusions
Major
findings
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You can read and print pdf-files with the Acrobat® Reader
®3.0. Program. This program is free.
Download it from the Acrobat web site: www.adobe.com OR
run the installation file ar32e301(1).exe in the directory
\Installation