greek traditional bio climatic design

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First Greek-Chinese Forum on the Environment, TEE, 3-4/12/2009, Athens1

Technical Chamber of Greece1st Greek Chinese Forum on the environment 3 - 4 / 12 /2009Thematic area: Bioclimatic Architecture

GREEK TRADITIONAL BIOCLIMATIC ARCHITECTURE

Christos Floros, architect5 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 inharmony with the natural environment.

Fascinated by the technological achievements of the 20 th century, we builtwithout limits, with the illusion that nature cannot punish us.

Now that we understood that we must build ecologically, it is useful toinvestigate our traditional architecture that was integrated in the ecosystem.

At the beginning of this paper, we present briefly the major components ofcontemporary bioclimatic architecture, with emphasis on minimizing the consumption

of energy that is not derived from renewable sources, water saving, anti-heatprovisions (considering the forthcoming climate change) and selection of buildingmaterials and techniques with ecological criteria.

Subsequently, we examine how each one of the above stated components ofcontemporary bioclimatic architecture, was realized in Greek traditional architectureand we present characteristic paradigms from various Greek areas.

This investigation is useful in:a. promoting understanding of Greek traditional architecture through an

ecological approachb. enriching the contemporary bioclimatic architecture know-how, so that it can

be creatively utilized

A THE MAJOR COMPONENTS OF CONTEMPORARY BIOCLIMATICARCHITECTURE

A1 MINIMIZING THE CONSUMPTION OF ENERGY THAT IS NOT DERIVEDFROM RENEWABLE SOURCES

Given that the construction and the operation of buildings consume a greatpercentage of energy that is not derived from renewable sources and they releaseCO2, we must:o prefer materials that are created and transported consuming the minimum energy

that is not derived from renewable sourceso apply building techniques that consume the minimum energy that is not derived

from renewable sourceso design buildings so as to minimize the dependence of their operation upon not

renewable energy sourceso apply building operational systems that consume renewable energy sources

(from the sun, air, water, land)

A2 WATER SAVINGWater saving in buildings can be attained with the following methods:

o collecting rainwater

o designing the most suitable hydraulic facilitieso recycling waste water


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Water saving in the surrounding landscape can be attained by permitting thesoil to absorb rainwater to enrich the aquifer and allow the function of thehydrological cycle.

It is also important to choose planting belonging to the ecosystem of eacharea, that does not require frequent watering.

A3 ANTI-HEAT PROVISIONSAnti-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 DESIGNA3.a1 minimizing direct solar gain

The major source of unwanted summer heat is direct solar gain. One of theprimary concerns in design should be minimizing the loads that impact our newbuildings, thus ensuring the success of any potential cooling strategies.Buildings should be designed with emphasis on:

A3.a1.1 avoiding extensive glazingA3.a1.2 locating window openings with climatic criteriaA3.a1.3 thermal insulationA3.a1.4 passive radiative coolingA3.a1.5 external shadingA3.a2 natural cooling

Natural cooling can be very effective. It can be attained through:A3.a2.1 natural ventilationA3.a2.2 evaporative coolingA3.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 coolingtechniques.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 andnights.

A3.b BIOCLIMATIC DESIGN OF BUILDING SURROUNDINGSA3.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 propershading and not disturb natural ventilation. Deciduous trees can be utilized moreeffectively.

A4 SELECTION OF BUILDING MATERIALS AND TECHNIQUES WITHECOLOGIC CRITERIA

Building materials and techniques must:o not release great quantities of CO2o not destroy O3 in atmosphere


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o not require great consumption of not renewable energy sourcesMaterials, in particular:

o must be recyclableo must be users friendlyo their extraction must not damage the natural environment

B THE MAJOR COMPONENTS OF GREEK TRADITIONAL BIOCLIMATICARCHITECTURE

B1 MINIMIZING THE CONSUMPTION OF ENERGY THAT IS NOT DERIVEDFROM RENEWABLE SOURCES

B1.a MINIMIZATION OF ENERGY CONSUMPTION FOR BUILDING MATERIALSTRANSPORTATION

Through a disturbed ecological approach, we often choose materials that arefriendly to the environment, but are imported from remote areas (e.g. wood imported

in Greece from Indonesia). Energy consumed for transportation of materials, is oneof 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 perfectchoice, and contributed substantially to the morphological wealth of Greek traditionalarchitecture.

When building materials with special properties were required, they searchedout to import them from the nearest of the areas where they could be found.

B1.b MINIMIZATION OF ENERGY CONSUMPTION FOR HEATING BUILDINGSMinimization of energy consumption for heating buildings can be attainedthrough 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 woodenfloor separated them.

We shall refer to thermal insulation later.

B1.c USE OF WATERMILLS AND WINDMILLSWatermills and windmills are some of the most interesting buildings of Greek

traditional architecture. Designed with special expertise in the use of renewableenergy sources, they are morphologically landmarks of our traditional settlements.B1.c1 Watermills

With watermills, waterfall dynamic energy was used to operate machines forgrain milling, powder milling, tannery, ice production and marble cutting.

Watermills can be considered as ancestors of contemporary hydroelectricprojects.


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B1.c2 WindmillsWindmills 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 havestrong winds. Some windmills were built in the mainland too.

B2 WATER SAVING

B2.a CISTERNSWater saving in traditional buildings in areas with no rivers and water springs,

is realized by collecting rainwater in cisterns. Cisterns were constructed in thebasement of the building or in outdoor area near the building. Outdoor cisterns areroofed.

Rainwater is mostly gathered on flat roofs. From the roof is driven to thecistern through vertical clay gutters. In some cases, rainwater falling on sloping orvaulted roofs, is driven to the cistern through sophisticated constructions.

Traditional building technology makes most cisterns absolutely watertight.

Public fountains, built mainly in the 18

th

century, are interesting architecturalconstructions that use water stored in vaulted cisterns.

B2.b BUILDING SURROUNDINGSIn building surroundings the ground is not paved, where it is not urgently

needed. Consequently, rainwater enriches the aquifer and the hydrological cyclefunctions properly.

B3 ANTI-HEAT PROVISIONSIn the Greek area, particularly south of the 39 th parallel, one of the main

objectives of the traditional architecture was to avoid overheating of the buildings.

B3.a BIOCLIMATIC BUILDING DESIGNAlmost all components of the contemporary bioclimatic architecture existed in

Greek traditional building design.B3.a1 minimizing direct solar gainB3.a1.1 avoiding extensive glazing

There is not extensive glazing in traditional Greek buildingsB3.a1.2 locating window openings with climatic criteria

Since antiquity builders were interested in locating window openings withclimatic 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 naturalcooling 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 andvaulted roofs provided some thermal insulation.

Under sloping roofs, wooden false ceilings were constructed, creating avacant 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 warmthe buildings.

Recent research worldwise concludes that we must paint white at least theroofs of buildings or apply white coverings. Scientists refer to the successful whitepainting of buildings, applied in the Cycladic islands and in other Mediterraneanareas.

B3.a1.5 external shadingExternal 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 coolingB3.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 externalwalls, 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 andthrough 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 coolingPassive ground cooling is provided during the warm periods in semi buriedbuildings and in buildings where some of their walls are in contact to sloping ground.

There are many semi buried buildings in Thira (Sadorini) island whereexcavation 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 spacesthat 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 wasnot bad, without need for expensive constructions and without energy consumption.

It is astonishing that semi-open-air spaces exist in Greece continuously fromancient 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 temperaturesfrom winter to summer. So, as there were no active systems for controlling buildingtemperature, they had different living rooms for winter and summer.

Winter living rooms were positioned in the lower storeys, behind thick externalwalls 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 wasavoided through:


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o cross ventilationo 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 SURROUNDINGSB3.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 arewhitewashed. This is a great percentage of the total pavement and heat absorptionis limited.B3.b2 natural ventilation routes

Aristotle, Ippodamos, Xenophon, Vitruvius and other great men haveinvestigated the buildings layout in settlements.

One of the criteria in creating the layout of Greek traditional settlements, isthe 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 theundisturbed wind flow, so as to create natural ventilation of the streets and topromote natural ventilation of the buildings.

The serpentine layout of the narrow streets of the traditional centralsettlement of Mykonos island, is a characteristic example, as it fully utilizes theetesian summer winds to cool both the settlement and each building and also toremove atmospheric pollutants.B3.b3 appropriate tree planting

It is obvious that they selected planting belonging to the ecosystem of eacharea.

They used trees, arbors and other planting to create shadow.Deciduous trees were used to create shadow during summer and not todisturb sun penetration during winter.

They never disturbed with planting the wind flow that was required for cooling.

B4 SELECTION OF BUILDING MATERIALS AND TECHNIQUES WITHECOLOGICAL CRITERIA

Building materials and techniques used in Greek traditional architecture:o did not release great quantities of CO2o did not destroy O3 in atmosphere

o did not require great consumption of not renewable energy sourcesMaterials, in particular:o were recyclableo were users friendlyo their extraction did not damage the natural environment.

greek traditional bio climatic design

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