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Technical Chamber of Greece 1 Greek – Chinese Forum on the environment 3 - 4 / 12 /2009
Thematic area: Bioclimatic Architecture
GREEK TRADITIONAL BIOCLIMATIC ARCHITECTURE
Christos Floros, architect
5 Avlidos Str, Athens 115 -27, tel. 0030 210 7220628, e-mail: [email protected]
Bioclimatic architecture of the 21st century resets the goal of human living in
harmony with the natural environment.
Fascinated by the technological achievements of the 20th century, we built
without limits, with the illusion that nature cannot punish us.
Now that we understood that we must build ecologically, it is useful to
investigate our traditional architecture that was integrated in the ecosystem.
At the beginning of this paper, we present briefly the major components of
contemporary bioclimatic architecture, with emphasis on minimizing the consumption
of energy that is not derived from renewable sources, water saving, anti-heat
provisions (considering the forthcoming climate change) and selection of building
materials and techniques with ecological criteria.
Subsequently, we examine how each one of the above stated components of
contemporary bioclimatic architecture, was realized in Greek traditional architecture
and we present characteristic paradigms from various Greek areas.
This investigation is useful in:
a. promoting understanding of Greek traditional architecture through an
ecological approach
b. enriching the contemporary bioclimatic architecture know-how, so that it can
be creatively utilized
A THE MAJOR
ARCHITECTURE
COMPONENTS
OF
CONTEMPORARY
BIOCLIMATIC
A1 MINIMIZING THE CONSUMPTION OF ENERGY THAT IS NOT DERIVED
FROM RENEWABLE SOURCES
Given that the construction and the operation of buildings consume a great
percentage of energy that is not derived from renewable sources and they release
CO2, we must:
o prefer materials that are created and transported consuming the minimum energy
that is not derived from renewable sources
o apply building techniques that consume the minimum energy that is not derived
from renewable sources
o design buildings so as to minimize the dependence of their operation upon not
renewable energy sources
o apply building operational systems that consume renewable energy sources
(from the sun, air, water, land)
A2 WATER SAVING
Water saving in buildings can be attained with the following methods:
o collecting rainwater
o designing the most suitable hydraulic facilities
o recycling waste water
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Water saving in the surrounding landscape can be attained by permitting the
soil to absorb rainwater to enrich the aquifer and allow the function of the
hydrological cycle.
It is also important to choose planting belonging to the ecosystem of each
area, that does not require frequent watering.
A3 ANTI-HEAT PROVISIONS
Anti-heat provisions are vital due to climate change. In warm climatic areas,
active cooling of buildings is more energy consuming than their active heating.
A3.a BIOCLIMATIC BUILDING DESIGN
A3.a1 minimizing direct solar gain
The major source of unwanted summer heat is direct solar gain. One of the
primary concerns in design should be minimizing the loads that impact our new
buildings, thus ensuring the success of any potential cooling strategies.
Buildings should be designed with emphasis on:
A3.a1.1 avoiding extensive glazing
A3.a1.2 locating window openings with climatic criteria
A3.a1.3 thermal insulation
A3.a1.4 passive radiative cooling
A3.a1.5 external shading
A3.a2 natural cooling
Natural cooling can be very effective. It can be attained through:
A3.a2.1 natural ventilation
A3.a2.2 evaporative cooling
A3.a3 ground cooling
The dissipation of the excess heat of a building to the ground is very effective,
when building temperature is higher than ground temperature.
It is attained either with passive ground cooling or with hybrid ground cooling
techniques.
A3.a4 outdoor living
Use of sheltered open-air spaces for out-door living (atriums, porticoes,
verandas, covered balconies) make life more comfortable during warm days and
nights.
A3.b BIOCLIMATIC DESIGN OF BUILDING SURROUNDINGS
A3.b1 landscape
Minimizing site areas covered with pavement is an antidote to the Urban Heat
Island phenomenon.
A3.b2 natural ventilation routes
Buildings must be located so as to create free routes for natural ventilation.
A3.b3 appropriate tree planting
Trees must be suitable for the ecosystem of each area, provide proper
shading and not disturb natural ventilation. Deciduous trees can be utilized more
effectively.
A4 SELECTION OF BUILDING MATERIALS
ECOLOGIC CRITERIA
Building materials and techniques must:
o not release great quantities of CO2
o not destroy O3 in atmosphere
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AND
TECHNIQUES
WITH
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o not require great consumption of not renewable energy sources
Materials, in particular:
o must be recyclable
o must be users friendly
o their extraction must not damage the natural environment
B THE MAJOR COMPONENTS OF GREEK TRADITIONAL BIOCLIMATIC
ARCHITECTURE
B1 MINIMIZING THE CONSUMPTION OF ENERGY THAT IS NOT DERIVED
FROM RENEWABLE SOURCES
B1.a MINIMIZATION OF ENERGY CONSUMPTION FOR BUILDING MATERIALS
TRANSPORTATION
Through a disturbed ecological approach, we often choose materials that are
friendly to the environment, but are imported from remote areas (e.g. wood imported
in Greece from Indonesia). Energy consumed for transportation of materials, is one
of the major factors that are responsible for environmental degradation.
The modern movement in architecture neglected localism and caused to
increase this degradation.
Use of local building materials in traditional architecture, was due to limited
transportation potential, in older times. Nevertheless, ecologically was a perfect
choice, and contributed substantially to the morphological wealth of Greek traditional
architecture.
When building materials with special properties were required, they searched
out to import them from the nearest of the areas where they could be found.
B1.b MINIMIZATION OF ENERGY CONSUMPTION FOR HEATING BUILDINGS
Minimization of energy consumption for heating buildings can be attained
through proper design, minimizing heat loss.
Thick stone or brick walls had a great thermal mass.
Living spaces (particularly those used during winter) had small external
openings.
There was often extensive earth contact, not only in semi – buried buildings,
but also in buildings where some of their walls were in contact to sloping ground.
The basement of some houses was used as animal shelter. Animal heat
warmed human living spaces on the above storey, as a heat transparent wooden
floor separated them.
We shall refer to thermal insulation later.
B1.c USE OF WATERMILLS AND WINDMILLS
Watermills and windmills are some of the most interesting buildings of Greek
traditional architecture. Designed with special expertise in the use of renewable
energy sources, they are morphologically landmarks of our traditional settlements.
B1.c1 Watermills
With watermills, waterfall dynamic energy was used to operate machines for
grain milling, powder milling, tannery, ice production and marble cutting.
Watermills can be considered as ancestors of contemporary hydroelectric
projects.
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B1.c2 Windmills
Windmills built from the 12th to the 19th century used wind energy for grinding
grain. They were mostly built on islands that do not have waterfalls, while they have
strong winds. Some windmills were built in the mainland too.
B2 WATER SAVING
B2.a CISTERNS
Water saving in traditional buildings in areas with no rivers and water springs,
is realized by collecting rainwater in cisterns. Cisterns were constructed in the
basement of the building or in outdoor area near the building. Outdoor cisterns are
roofed.
Rainwater is mostly gathered on flat roofs. From the roof is driven to the
cistern through vertical clay gutters. In some cases, rainwater falling on sloping or
vaulted roofs, is driven to the cistern through sophisticated constructions.
Traditional building technology makes most cisterns absolutely watertight.
Public fountains, built mainly in the 18th century, are interesting architectural
constructions that use water stored in vaulted cisterns.
B2.b BUILDING SURROUNDINGS
In building surroundings the ground is not paved, where it is not urgently
needed. Consequently, rainwater enriches the aquifer and the hydrological cycle
functions properly.
B3 ANTI-HEAT PROVISIONS
In the Greek area, particularly south of the 39th parallel, one of the main
objectives of the traditional architecture was to avoid overheating of the buildings.
B3.a BIOCLIMATIC BUILDING DESIGN
Almost all components of the contemporary bioclimatic architecture existed in
Greek traditional building design.
B3.a1 minimizing direct solar gain
B3.a1.1 avoiding extensive glazing
There is not extensive glazing in traditional Greek buildings
B3.a1.2 locating window openings with climatic criteria
Since antiquity builders were interested in locating window openings with
climatic criteria.
In general, they preferred to locate the larger openings on the southern and
eastern walls. They tried to avoid openings on the northern and western walls.
Nevertheless, they created small openings on the northern walls to attain natural
cooling during the warm periods.
Arrangements differ depending upon the microclimate of each area.
B3.a1.3 thermal insulation
There was no special provision for thermal insulation. However, flat and
vaulted roofs provided some thermal insulation.
Under sloping roofs, wooden false ceilings were constructed, creating a
vacant space that helped to insulate the functional spaces underneath.
B3.a1.4 passive radiative cooling
In Cycladic islands (in the Aegean Sea) building cells are painted absolutely
white. Continuous whitewashing maintains this absolute white. Consequently the
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greatest percentage of long wave sun radiation is reflected and does not over warm
the buildings.
Recent research worldwise concludes that we must paint white at least the
roofs of buildings or apply white coverings. Scientists refer to the successful white
painting of buildings, applied in the Cycladic islands and in other Mediterranean
areas.
B3.a1.5 external shading
External shading is attained with projecting canopies, arbors, trees and
climbing plants planted in proper places.
Loggias shade window openings behind them.
Wooden window shutters, either solid or “French type” regulated entrance of
sunlight in building interiors.
B3.a2 natural cooling
B3.a2.1 natural ventilation
Main window openings were placed, if possible, at the southern or eastern
external walls of the building and small openings were created at the top of external
walls, opposite the main openings and preferably on the northern walls.
During summer etesian winds, they left the windows open and wind flow
entering from the small northern windows run through the building, cooling it.
During summer nights, when external temperature is lower than the
temperature inside the building, hot air flows out through the small top windows and
through the chimneys.
B3.a2.2 evaporative cooling
Evaporative cooling was a technique used in ancient Egypt and Persia.
In warm Greek areas there is not adequate water, in general and
consequently evaporative cooling is not used in traditional Greek architecture.
B3.a3 ground cooling
Passive ground cooling is provided during the warm periods in semi – buried
buildings and in buildings where some of their walls are in contact to sloping ground.
There are many semi – buried buildings in Thira (Sadorini) island where
excavation of volcanic earth is easy.
B3.a4 outdoor living
A famous Greek author wrote that Greek living, is outdoor living.
Particularly, south of the 39th parallel, the climate is so friendly, that people
avoid most of the year the internal built spaces, preferring to live in roofed spaces
that have at least one of their sides open to the natural environment.
Designing semi-open-air spaces with appropriate orientation was a critical
bioclimatic option, as it created pleasant and healthy living, when the weather was
not bad, without need for expensive constructions and without energy consumption.
It is astonishing that semi-open-air spaces exist in Greece continuously from
ancient times till now.
B3.a5 designing different spaces for winter and summer
North of the 39th parallel in Greece, there is a great difference in temperatures
from winter to summer. So, as there were no active systems for controlling building
temperature, they had different living rooms for winter and summer.
Winter living rooms were positioned in the lower storeys, behind thick external
walls with small openings.
Summer living rooms were positioned in the upper storey, behind thin
external walls with large openings and they had proper orientation. Overheating was
avoided through:
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o cross ventilation
o building envelopes with small thermal mass (because the night period is not long
enough to cool building envelopes with great thermal mass)
B3.b BIOCLIMATIC DESIGN OF BUILDING SURROUNDINGS
B3.b1 landscape
Limiting pavement area to the minimum essential, overheating is avoided.
This also contributes to the proper functioning of the hydrological cycle.
In Cycladic islands the perimeters of each paving slab and their joints are
whitewashed. This is a great percentage of the total pavement and heat absorption
is limited.
B3.b2 natural ventilation routes
Aristotle, Ippodamos, Xenophon, Vitruvius and other great men have
investigated the buildings layout in settlements.
One of the criteria in creating the layout of Greek traditional settlements, is
the protection from the wind or the utilization of the wind for cooling and clearing the
settlement, depending upon local characteristics.
In warm areas, traditional settlements have layouts that permit the
undisturbed wind flow, so as to create natural ventilation of the streets and to
promote natural ventilation of the buildings.
The serpentine layout of the narrow streets of the traditional central
settlement of Mykonos island, is a characteristic example, as it fully utilizes the
etesian summer winds to cool both the settlement and each building and also to
remove atmospheric pollutants.
B3.b3 appropriate tree planting
It is obvious that they selected planting belonging to the ecosystem of each
area.
They used trees, arbors and other planting to create shadow.
Deciduous trees were used to create shadow during summer and not to
disturb sun penetration during winter.
They never disturbed with planting the wind flow that was required for cooling.
B4 SELECTION OF BUILDING
ECOLOGICAL CRITERIA
MATERIALS
AND
TECHNIQUES
WITH
Building materials and techniques used in Greek traditional architecture:
o did not release great quantities of CO2
o did not destroy O3 in atmosphere
o did not require great consumption of not renewable energy sources
Materials, in particular:
o were recyclable
o were users friendly
o their extraction did not damage the natural environment.
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