Architecture without Architects Green Design Tips by Insects, Animals and Vernacular Buildings
Alexandros Christodoulou
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Green design plays a major role in the design process of buildings, creating a whole new industry revolving around concepts such as sustainability, green design, environmental “friendliness”, renewable energy etc. In our new struggle towards a smarter building approach we turn to natural and vernacular buildings to find out how organisms and primitive civilizations manage to sustain without the technological miracles modern man has achieved. Once again, in modern day, we could find simple answers and directions towards a built environment that will not continue to blossom in the expense of the natural environment, but instead, will form a unity along with the latter. The Earth’s finite non-renewable energy resources make it urgent for designers to search into the natural and vernacular “portfolio” for low-energy consumption solutions.
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Termites Spiders Beetles Birds Wasps Prairie-dogs VERNACULAR ARCHITECTURE Bedouins Eskimoes Native Americans Persians Ancient Greeks
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ANIMAL ARCHITECTURE
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Termites probably deserve nature’s bioclimatic architecture prize. To begin with, the Magnetic Termite has gained its name by building mounds up to 3.7m high, 1m thick and 3m wide, that have their long axis aligned north to south, so as to present a large surface in morning and evening sun and a small surface at midday sun. Thus they manage to lower the inside temperature to 34oC, while scientifically reoriented nests rose to over 40oC! The termites usually congregate in the shaded west side of the mound in the morning, and on the shaded east side in the evening. The slim shape of the mound allows sufficient air ventilation through the pores of the surfaces. Other termite species that build thicker mounds, make vertical corridors to lead hot air and C02 outside the mount via “chimneys� at the top of the mount.
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Termites North Australia/Congo Mounds
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The design employed by Cubitermes species to survive during the sudden floods of Congo’s tropical climate is equally “rational”: the main living area is lifted from the possible flood water level with a column (!), while the top of the mound features a mushroomlike cap to protect the mound from rain. Needless to say that in dry savvanah habitats the mound is constructed without the cap by the same species.
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1. A clever shape and positioning of a building allows you to use the heat from the sun when you need it, and avoid it when there is a danger of overheating 2. A big (external surfaces)/(built mass) ratio means that more spaces are close to the outer environment and can be ventilated through openings. 3. The design of the building should vary according to the local climatic situation 4. During daytime, different rooms of the building might be more pleasant, which can be used to wisely distribute functions of the building in the floor plan. 5. In areas with flood risk it is important to elevate all vital spaces from the ground. 6. In rainy areas, the roof can be formed in a way that determines the route of the rain water, and guide it away from from the main building 7. A hole in the top of the building along with a vertical corridor (chimney) leading to it allows hot air to escape the building naturally.
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Micrathena gracilis or most commonly “Spined Micrathena�, is a spider species with interesting temperature control strategies: The orientation of the web is used to keep the web’s user cooler, in open spacies with a lot of light and warmer in shady places. This is acheived by North-South web orientation in shaded habitats and East-West orientation in well illuminated habitats. It was evem verified scientifically (Biere and Uetz, 1981) by measuring the temperature of dead spiders, that this strategy really affected the body temperature of the spiders in comparison to spiders with not so well orientated webs. Spider webs are also examples of tensile architecture in nature, with which a lot of material can be saved from being wasted in absorbing buckling and bending moments.
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Spiders (Micrathena gracilis) Various locations Spider webs
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1. Proper orientation differs, depending to the amount of shade or light in the area. 2. In a shadey area you need maximum surface towards the east and west, so a north-south orientation to absorb heat, if needed. 3. In a well illuminated hot area it might be best to have an east-west orientation to avoid the heat from the east and west wall surfaces. 4. Tensile architecture needs less material to cover large spans.
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This particular beetle didn’t let the midday desert heat minimise the prey capturing hours. Building a 4cm turret and thus distancing themselves from the burning desert sand they manage to wait for prey all day long, while other beetles hide in the underground. The shade that the turret does, also lures prey to the site, working also as a trap. (Apparently, passive temperature control can also have side benefits.) In an arid coastal region of the Namib desert a beetle of the genus of Lepidochora proves to be potent water managers: When the weather turns to fog, they construct shallow trenches as dew traps, and conserve the rare rainwater. To make moisture last longer, the trench is oriented parallel to the wind direction and the edges of th trench are raised. When neeeded, the water can be extracted by the Beetle.
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Beetle (Cicindela willistoni) Central USA desert/Namib desert Turret on top of Burrow
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1. In very hot climates elevating the building from the hot ground can have a positive effect. 2. Don’t forget that you can creatively use the shade that your buildings produce. 3. Water storage in dry climates is extremely important. 4. Water can also be used to improve the condition of the air, for example moisturise dry air etc.
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These birds have found a way to warm their eggs without having to sit around all day, biomass does the trick for them instead! The male parent piles dead leaf litter to make a 1.5m tall mound (of 3-4m diameter). The dead leaf compost heap produces heat while fermenting, even too much heat at times: If the desired temperature (33oC) is exceeded the male parent drills holes in the mound, also to reduce CO2 levels inside it. In early spring when the fermentation rate declines the mound can be opened up at the top to let sun heat the mound.
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Gallinaceous birds Australia, Nea Guinea Mounds for auto-egg warming
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1. Rotting biomass could be a cheap means of heating, especially in winter time. 2. In autumn and winter a building has to be as closed as possible to retain the inside heat. 3. In spring and summer, consider opening up the top of your building, to collect as much heat as possible for your house needs. 4. In rooms with a danger of excessive heat and/or CO2 concentration, openings are necessary
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1. Rainfall rate in a place determines largely the form of the roof. 2. Smoothing edges and surfaces of the building envelope enhances the responce to rainfall
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Steep roofs in rainy areas are not a human invention after all. Wasps apparently have also “designed� their nests in such a way, that allows them to inhabit not only in well protected sites, but also exposed situations. The tall conical roof that they employ in this occassion is made with multiple layers of nest envelope, to sufficiently protect the comb that lies underneath. The smooth surface and the soft edges of the outer skin of the nest prevents mechanical damage from the rainfall.
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Wasp (Vespa affinis) Indo-Malaysian Tropics Nest
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The burrow systems of prairie-dogs are usually extremely complex underground corridor systems that need to be ventilated in order to import the oxygen needed and to keep CO2 in low levels. As Steven Vogel and his collaborators pointed out in their study of Cynomis ludovicianus prairie-dog species, the ventilation system of the burrows works this way: On both sides of long corridors, the prairiedogs build mounds for wind entrance and wind exit. The entrances are wider and on a lower mound (half the height of the exit mound), and thus the air speed over the exits is bigger than over the entrances. According to Bernoullis principle, this means that pressure over the exits is lower than pressure over the entrances and this causes an air flow from the entrances to the exits. On the other hand, the prairie-dogs do not employ this mechanism in all the corridors
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Black-tailed prairie-dog Kansas Burrow
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1. Air flow parallel to the surfaces of the building can be used to motivate ventilation inside the building. 2. The opening designed to be the entrance of the incoming air should be lower than the opening designed to be the exit. 3. Air streams inside the building decrease humidity. 4. The route of the ventilation stream should be carefully designed as some spaces might be better off it.
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of the burrow because if they did so, all the corridors would lack humidity. The prairiedogs need humidity to reduce water loss due to perspiration, as they often inhabit dry climates. So perpendicular to the ventilated air streams they build corridors with no mounds at both ends, where humidity reaches two to five times the atmospheric humidity.
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The Bedouin black tent offers another excellent example of clever vernacular bioclimatic design. Made of woven goat’s hair and/or sheep’s wool, very loosely woven, the black tent protects inhabitants from the main stream of air while allowing air circulation through the loose weave. Meanwhile the goat hair cloth can also protect from rain, as it swells up with humidity, making the tent hard as a drum. It is also important to note that black tents of the bedouins are a primitive example of tensile architecture, which is the most economic way to roof large spans, because they do not require the considerable amount of construction materials needed in the conventional buildings to absorb the buckling and bending moments in compression members.
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Bedouins Arabian Desert Black Tent
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• Surfaces with pores allow ventilation while blocking massive air streams. • Humidity and temperature changes the dimensions and features of materials and can be used as an automatic control mechanism if used wisely. • Temporary settlements can be functional and comfortable. • Ropes in tension can transform soft clothes to stable walls.
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Eskimos Architect: Circumpolar Region Place: Igloo Building: Igloos are the most “representative and exaggerated example of popular architecture in cold climates�, combining many techniques that make such extreme climate conditions habitable. In the struggle against cold the eskimoes have an important ally in abundance: Snow itself has good insulation properties. Besides snow the inside walls of the igloo are covered with seal skins filled with moss for even more insulation. The skins might also be brought down to make use of the heat radiation from the sun that can pass througn the edges of the ice blocks. The hemispheric shape of the igloo is ideal as it has the minimum external surface to volume ratio, because the inside heat escapes through the wall surfaces. It also reduces the wind forces on the surfaces. The igloos are built to have a lower floor for the entrance and a raised floor for the
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main living areas to use air stratification and live in the upper hotter layer of air. Using these techniques in addition to the relatively small size of the igloo ensures that human body heat and a seal oil lamp is enough to heat the settlement.
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1. Keep the building as small as possible to need less energy to heat it 2. Use air stratification, as upper air layers are hotter than the lower. 3. Shape matters. The shell shape of the structure defines how much surface per volume the building is going to have, and so how much interaction with the local temperature conditions. 4. Settle your priorities and make compromises. Insolation and Insulation rarely came together in vernacular architecture, and even nowadays insolation, insulation and economic don’t go together, so a designer must choose his main design focuses. 5. Look for locally available insulation materials
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Another “representative and exaggerated� example of vernacular architecture, for hot and humid climates this time, is a stretch of the word building: The hammock, consisting of just a sling of woven from a bark of hamack tree or later from sisal fibers suspended between two points, was one of the things that were most noted by the Spanish invaders in America. The reason for the hammock being a representative example is that basically all the buildings in these areas try to do exactly that: allow wind flow in every direction to carry away away humidity and heat while protecting from the sun, as hammocks are always placed in a shady site, or shade-providing constructions are added. The soft swinging motion produces extra air movement with minimal effort needed. Thermal mass of hammocks are minimal as is the case for buildings in hot and dry cli-
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Native Americans Carribean Hammock
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1. Immaterial architecture can be the best architecture. 2. In hot & humid climates, when temperature difference between night and day is not big, (thermal) mass is the enemy, radiating extra heat. 3. In hot & humid climates, let the wind flow in any direction possible 4. Think of human activities that can improve their own environment with little effort. 5. Search for naturally shaded areas in your building site.
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BIOCLIMATIC DESIGN TIPS BY NATIVE AMERICANS
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mates, where thermal buffering is useless. As H.Coch remarks pointedly, “To sum up, in these climatic zones the role of protection that we normally attribute to the building results in the most immaterial architectural constructions.� The elevation from the ground served also as a protection for snakes and insects.
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Air-conditions today are responsible for the consumption of the 60% of the total energy consumption in Bushehr. On the other hand traditional buildings have been inhabited pleasantly for ages using some simple bioclimatic techniques. To begin with, walls up to 70cm made with materials of great thermal inertia (adobe bricks, mud), delayed the entrance of heat until the night when it is least annoying. Windows, mostly facing the south, had colored glazing to decrease the amount of thermal energy entering without obstructing the outdoor view. Overhangs, the surrounding buildings (large building compactness) and deciduous trees shaded as much surface as possible. Heat-producing kitchen was seperated from the building. The roofs and external surfaces where lightly coloured to reduce sun-ray absorbance. While these techniques are quite common in
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Persians Bushehr-Shooshtar, Iran Dwellings with Wind Catcher
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hot climates, rarer is the use of louvers jutting out over the building serving as wind-catchers. The wind enters through the catchers and is leaded downwards ventilating the building. The louver and windows were orientated to capture the prevailing wind direction. The building as a whole had East-West orientation to have a larger surface to the cooler south. In another region of Iran called Shooshtar with a hot & humid summer, traditional architecture has designed different rooms depending on the hour of the day: In midday they went to underground areas called “Shavadun”, in the afternoon they go to the Semi-open spaces called “Ivan”, and at night they sleep at the roof or at the “Shavadun”. The underground spaces under 6 meters depth, take months to be affected from environmental changes so they can keep winter coolness and summer heat for months, always staying within the human comfort zone. The underground areas are naturally ventilated using the thermal chimney effect and naturally illuminated using daylight through ground holes.
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1. Use thick walls when temperature difference between night and day is big. 2. Colored glazing windows can reduce the heat entering the building still allowing in outdoor view and light. 3. Look around your building site for natural shade, otherwise... 4. Design your shade. 5. Colour your surfaces wisely: Light colours reflect sunrays, dark colours absorb them. 6. The kitchen produces heat. In hot climates keep it out of the building. 7. In dense cities, look up. Jutting out volumes can capture wind or light needed for the building. 8. Every part of your building has its own ideal orientation. 9. Different time of day, different place to stay. 10. Go underground, Stay cool.
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The Cyclades islands in the Aegean sea are famous for the white houses which serve to reflect the sunrays and the heat they produce, but their pearly white colour was not generalised until the 1960s. They did however prefer light colours for the outer walls in most of the cases, mostly using asbestos which produces an almost white outcome. Other bioclimatic techniques have been used here as well though: The flat roof minimizes the heat gains, as a flat roof’s surface is the smallest possible. What is more outdoor cooking is prefered in summer, to avoid overheating due to kitchen heat. Dense urban design, also providing protection against pirate invasions, offered shade from one building to the next. Finally wind was used as an energy source for milling since the 11th century.
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Ancient Greeks Cyclades, Aegean sea Dwellings
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BIOCLIMATIC DESIGN TIPS FROM ANCIENT GREEKS
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1. External Wall Colours affect solar gains. 2. Flat roofs decrease solar gains. 3. In temperate climates, design both an outdoor and an indoor cooking area. 4. A dense building environment can provide shade to outer walls. 5. Use renewable sources available in your area.
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T H E M E S 1 0 + 1
From Wasps, to Termites and Malay vernacular architecture, probably the most basic reaction to a climate with heavy rainfalls is a steep roof. Termite mounds in Congo’s tropical climate feature a mushroom-like cap to protect the mound from rain featuring grooves to determine the route of the water. Wasps on the other hand prefer a conical roof with smooth surface design. On the other hand in hot and dry climates (Ancient Greeks, Persians) a flat roof can be used to avoid overheating, as the roof is the surface that gathers more sunrays than any other building surface. To get maximum volume under the roof for the minimum surface possible, a hemispherical igloo solution is suggested.
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1. Roof Design
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No building can be described bioclimatic if its not positioned or shaped according to its orientation. In areas where the sunrays are used to heat the building, a north-south orientation is prefered (Termites, Spiders in shady environments), because in this case the surfaces facing east and west gather heat during the morning and the evening respectively. On the other hand, in very hot areas (Arabs, spiders in well lit environments) where heat is always unwanted, an east-west orientation is preferable, to increase the surfaces facing the cool north (or south for the south hemisphere) and make a pleasurable area in the center of the building where the sun heat cannot reach.
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2. Orientation
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Termite mounds on one hand and igloos on the other hand demonstrate how you can maximize or minimize the above ratio, to increase or decrease respectively the correlation of the building and the environmental conditions. More surfaces also mean that more rooms have access to the environmental air through openings.
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3. (External surfaces)/(Volume) ratio
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Termites and Persians building “designs� require that different areas of the building be active according to the time of day. Underground, central floors, or the top of the building can be ideal for a specific time of day. This way of thinking could be used when assigning functions to a floor plan design. Other than that a designer can also think of ways to avoid the kitchen heat in hot areas, separating it from the rest of the building (Persians), or even make two cooking rooms, an outdoor one for summer and an indoor one for winter (Ancient Greeks).
R E C U R R E N T
4. Smart floor plan.
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Either to create shade (beetles) or to save the main building areas from sudden floods (termites), from ground’s heat (beetles), or even from dangerous creatures of nature (Native Americans) moving the main building’s volume upwards could be a simple solution to complex problems.
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5. Consider elevation
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Openings the top of a building can be used for: • Ventilation(1): hot air leaves the building forcing a stream of air in the rooms(termites, eskimos, prairie-dogs). • • Ventilation(2): Air enters the building from the top and ventilates the rooms underneath (prairie-dogs, Persians) • Heating by sunrays (gallinaceous birds) • • Reducing C02 concentration inside a building (Prairie-dogs, Gallinaceous birds, Termites).
R E C U R R E N T
6. Openable top
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Following the path of the forces natural distribution inside an element (Termites) and using as many elements in tension as possible (Bedouins, Spiders) can result in the cutting down on building material with major impact to the sustainability of the building.
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7. Cooperate with a structural
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Storing water can result in a better living environment (beetles) in very hot areas. Each room could be designed for its own ideal moisture levels, using or avoiding ventilation accordingly (prairie-dogs).
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8. Control Water/Moisture
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Nature and Vernacular Architecture uses some alternative sources of heat, some of which almost entirely forgotten in modern architecture. Apart from the human body which provides heat that is enough for small insulated spaces, heat can also be produced by rotting biomass (galinaceous birds) and burning biomass (Eskimoes). What is more the thick outer shell walls (termites, ancient arabs) and a kitchen in use (Ancient Greeks) can also contribute the energy demand for heating from non-renewable sources.
R E C U R R E N T
9. Alternative heat sources
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Air can provide comfort or distract it, so its handling is an important factor for buildings. The Bedouin’s black tent and the hammock are simple constructions that deal successfully with local wind conditions. The Bedouins blocked the main stream of air but allowed it to flow through the pores of the cloath to ventilate the inside area. The hammock used a minimal effort by the user to generate small air flows in a very hot environment where mild wind flows would be pleasurable. The prairie-dog and the ancient arabs have generated passive ventilation systems using the streams of air of the environment. Finally Ancient Greeks have used wind energy to operate windmills since the 11th century A.D.
R E C U R R E N T
10. Controlling air streams
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Dense cities provide valuable shade to buildings from their surrounding establishments (Persians, Ancient Greeks) in hot environments. Arabs also used overhangs over the streets while Greeks made roofed passages uniting buildings.
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10+1. Bioclimatic Urban Design
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1. Hansell, Michael Henry. “Animal architecture and building behaviour.” Longman, 1984. 2. Hatamipour, M.S., and A. Abedi. “Passive cooling systems in buildings: Some useful experiences from ancient architecture for natural cooling in a hot and humid region.” Energy Conversion and Management 49, no. 8 (August 2008): 2317-2323. 3. Hegde, Lekha S. “Indoor air temperatures and energy use: A comparative field study of vernacular, conventional, and alternative‐technology construction in India.” Environmental Quality Management 19, no. 4 (June 1, 2010): 51-71. 4. Helena, Coch. “Chapter 4—Bioclimatism in vernacular architecture.” Renewable and Sustainable Energy Reviews 2, no. 1-2 (June 1, 1998): 67-87. 5. Kahn, Lloyd. “Shelter”. Shelter Publications, Inc., 2000. 6. Ken-ichi, Kimura. “Vernacular technologies applied to modern architecture.” Re-
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newable Energy 5, no. 5-8 (August 1994): 900-907. 7. Li, Jingxia. “The bioclimatic features of vernacular architecture in China.” Renewable Energy 8, no. 1-4 (May): 305-308. 8. Mike, Hansell. “An A-Z of evolution would benefit town planners.” Trends in Ecology & Evolution 24, no. 5 (May 2009): 239-240. 9. Nerdinger, Winfried. “Frei Otto: complete works : lightweight construction, natural design.” Birkhäuser, 2005. 10. Otto, Frei, and Juan María Songel. “A Conversation with Frei Otto.” Princeton Architectural Press, 2010. 11. Prodromou, Michael. “Vernacular Architecture- A Lesson in Sustainable Housing”. TU Delft course AR0531-I. Designer’s Manuals, Spring 2009. 12. Rezaee, R., R. Vakilinejad, and M. Shahzadeh. “The ‘Shavadun’ as an ecological solution for architecture in a hot climate.” 303-313, 2009. http://library.witpress. com/pages/paperinfo.asp?PaperID=19832. 13. Various authors. “Hammock.” Wikipedia. org, n.d. http://en.wikipedia.org/wiki/ Hammock#Mexican_and_Mayan_hammocks.
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14. Vogel, S., C.P. Ellington Jr., and D.L. Kilgore Jr. “Wind-induced ventilation of the burrow of the prairie-dog, Cynomys ludovicianus.” Journal of Comparative Physiology 85, no. 1 (1937): 1-14. 15. Wilson, Michael, and Brian Dupuis. “From Bricks to Brains: The Embodied Cognitive Science of Lego Robots.” Athabasca University Press, 2010. 16. Rudofsky, Bernard. “Architecture Without Architects: A Short Introduction to Non-Pedigreed Architecture.” University of New Mexico Press, 1987. a
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“Bioclimatic Architecture Without Architects” was written by Alexandros Christodoulou as an assignement for TU Delft AR0531 - Smart & BioClimatic Design in September-October 2011 under the valuable guidance of prof. Eric Van den Ham and prof. Andy van den Dobbelsteen and the also valuable remarks of ARO531 coursemates.
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