REPUBLIC OF TURKEY UNIVERSITY OF DICLE
INSTITUTE OF NATURAL AND APPLIED SCIENCES
ANALYZING CLIMATE RESPONSIVE ELEMENTS IN ERBIL VERNACULAR ARCHITECTURE IN ECOLOGICAL MANNER
HAVAL SAMI ALI
ADVISOR
Asst. Prof. Dr. Nurtekin ÖZEN
MSc THESIS
DEPARTMENT OF ARCHITECTURE
DIYARBAKIR June 2016
I
ACKNOWLEDGMENTS
I would like to convey my utmost thanks to my advisor Dr.Nurtekin ÖZEN for his continuous and uncommon support throughout this process, and my entire residency at Diyarbakir. I would like also to thank Dr. Can Tuncay AKIN who generously offered me his expertise and time, thank you for going through my drafts and always providing helpful feedback. Without your guidance, the thesis would not be what it has become.
I would like thank everybody who helped me in data collection process especially my friends. Finally, I would like to thank my family for their encouragement and love.
II TABLE OF CONTENTS ACKNOWLEDGMENTS ... I Table Of Contents ... II ABSTRACT ... IV ÖZET ... V LIST OF TABLES ... VI LIST OF FIGURES ... VII ABBREVIATIONS ... IX
1. INTRODUCTION ... 1
1.1. Introduction to the Study ... 1
1.2. Problem Statement: ... 2
1.3. Purpose of the Study ... 2
1.4. Scope of the Thesis ... 2
2. LITERATURE REVIEW ... 5
2.1. Ecological Architecture: ... 5
2.2. Vernacular Houses... 7
2.3. Climate Responsive Elements ... 9
2.4. Erbil ... 13 2.4.1. Location of Erbil ... 13 2.4.2. History of Erbil ... 13 2.4.3. Erbil Climate ... 16 2.3.4. Population of Erbil ... 16 2.3.5. Socio-Cultural context ... 16
2.5. History of Housing Development in Erbil city: ... 17
2.5.1. Before 1930 housing development ... 17
2.5.2. 1930-1980 Period Housing Development ... 18
2.5.3. 1980-2003 Period... 19
2.5.4. After 2003 Period ... 20
3. ERBIL VERNACULAR ARCHITECTURE ... 25
3.1. Erbil Settlement ... 25
III
3.3. Alleyways ... 27
3.4. Mahallas (quarters) ... 27
3.5. Dating of the Houses ... 28
3.6. Housing Typology ... 30
3.7. Erbil Vernacular Houses Building Properties ... 33
4. CLIMATE RESPONSIVE ELEMENTS IN ERBIL VERNACULAR ARCHITECTURE... 41
4.1. Methodology: ... 41
4.2. Definition of the case study: ... 42
4.3. Ecological criteria: ... 42
4.3.1. Economy ... 43
4.3.2. Socio-cultural criteria ... 43
4.3.3. Environmental criteria ... 46
4.3.3.1. Town planning ... 46
4.3.3.2. Building orientation and form ... 47
4.3.3.3. Wind Factor ... 49
4.3.3.4. Natural ventilation ... 50
4.3.3.5. Solar shading ... 52
4.3.3.6. Natural lighting ... 55
4.3.3.7. High thermal mass and insulation by material ... 57
4.3.3.8. Evaporative cooling and using plants as cooling ... 59
4.3.3.9. Earth cooling ... 60
4.4. Results ... 60
4.4.1. Climatic Responsive Elements in Erbil Vernacular Houses ... 61
4.4.2. Ecological Purpose of Climatic Responsive Elements: ... 62
5. CONCLUSION ... 69
5.5. Main Conclusion ... 69
5.6. Suggestions for Future Studies ... 70
REFERENCES ... 71
IV
ABSTRACT
ANALYZING CLIMATE RESPONSIVE ELEMENTS IN ERBIL VERNACULAR ARCHITECTURE IN ECOLOGICAL MANNER
MSc THESIS Haval Sami Ali
DEPARTMENT OF ARCHITECTURE
INSTITUTE OF NATURAL AND APPLIED SCIENCES UNIVERSITY OF DICLE
2016
The most important issue of the world in terms of construction presently is energy use. Every year many conferences are held on energy in general and specially on energy consumption of buildings. The energy resources are continuously going to be consumed. Behind the researches for an alternative energy sources, the reducing of energy use especially the operating energy is another way to survival of life on the earth planet.
The main outline of this study is the climate responsive elements which are used in vernacular houses as a part to solutions of cooling, heating, ventilation and lighting of houses without any mechanical support to reduce energy used as operating energy.
In hot arid regions the main problems of the buildings are cooling and heating systems. In this research the vernacular houses of Erbil which are located inside the citadel town are taken as a case study to analyze the elements used in them as a method to solve climatic problems. The elements will be analyzed according to shape, size and their position refer to façade. The energy performance of the building materials will be the main focused part of the study by analyzing the construction materials energy performance and heat transfer capacity.
At the end of the research some research paths will be suggested to be pursued by the next generation of researchers and designers.
V
ÖZET
ERBİL KONUT MİMARİSİNDE İKLİME DUYARLI YAPI ELEMANLARININ EKOLOJİK ANLAMDA ANALİZİ
YÜKSEKLİSANS TEZİ Haval Sami Ali
DİCLE ÜNİVERSİTESİ FEN BİLİMLERİ ENSTİTÜSÜ MİMARLIK ANABİLİM DALI
2016
Çağımızın inşaata dair en önemli sorunu enerji kullanımıdır. Her yıl genel olarak enerji ve özellikle de binalarda enerji tüketimi ile ilgili çeşitli konferanslar düzenlenmektedir. Ve enerji kaynakları sürekli olarak da tüketilen olacaktır.
Alternatif enerji kaynaklarına dair yapılan çalışmalarla asıl hedeflenen özelliklede binalarda kullanılan işletim enerjisinin kullanımının düşürülerek dünyadaki yaşamın devamının sağlanmasıdır.Çalışma genel olarak,geleneksel evlerde herhangi mekanik bir desteğe ihtiyaç duymadan işletim enerjisini düşüren, soğutma, ısıtma, havalandırma ve aydınlatma çözümleri için kullanılan iklime duyarlı elemanlar hakkındadır.Sıcak ve kurak bölgelerdeki binaların temel problemleri ısıtma ve soğutma sistemleridir.
Bu araştırma, Erbil kalesi içinde yer alan geleneksel evlerde söz konusu iklimsel sorunların çözümü için kullanılan elemanların analizi için yapılan çalışmayı konu edinmiştir. Elemanların şekil, boyut ve pozisyonlarına cepheye bakılarak analiz edilecektir.İnşaat malzemelerinin enerji performansı ve ısı kapasitesi incelenen yapı malzemelerinin enerji performansı bu çalışmanın odak noktası olacaktır.
Araştırmanın sonunda ise gelecek araştırmalara ve yeni nesil tasarımların yapılması adına bazı öneriler önermek hedeflenmektedir.
VI
Table No Page
VII
LIST OF FIGURES
Figure No Page
Figure 2.1. Basic consumption sectors as shown in the energy statistics. ... 5
Figure 2.2. Location of Erbil in Iraq... 13
Figure 2.3. Erbil birdseye view ... 13
Figure 2.4. Shanidar cave ... 14
Figure.2.5. Erbil ancient citadels urban Plan ... 15
Figure 2.6. Erbil Choli Minaret ... 15
Figure 2.7. Average climate data for Erbil for 2014... 16
Figure 2.8. Urban plan of the Erbil settlement before 1930. ... 18
Figure 2.9. The Style of House Period (1930-1980) ... 19
Figure 2.10. The Style of House Period (1980-2003) ... 19
Figure 2.11.a. Luxury Houses in Erbil ... 20
Figure 2.11.b. Luxury Houses widely used style ... 20
Figure 2.12. Italyan city gated community ... 21
Figure 2.13. Parkview gated community ... 21
Figure 2.14.a. 100m2 row houses ... 22
Figure 2.14.b. 100m2 mirrored plan ... 22
Figure 3.1. Location of Erbil old settlement ... 26
Figure 3.2. Erbil citadel mount. Source: Google earth ... 26
Figure 3.3. Erbil citadel alleyways ... 27
Figure 3.4. Erbil citadel quarters. ... 28
Figure 3.5. Palace like houses in Erbil Citadel ... 30
Figure 3.6. Medium sized houses in Erbil Citadel ... 30
Figure 3.7. Small sized houses in Erbil Citadel ... 31
Figure 3.8. Regular shape of the houses opened to courtyard ... 31
Figure 3.9. House plan showing the entrance and division in courtyard ... 32
Figure 3.10. House plan shows the courtyard in the middle ... 32
Figure 3.11. House plan shows twin house with the same entrance ... 33
Figure 3.12. A Block of palace-like house type ... 34
Figure 3.13. A Block of medium sized house type ... 34
Figure 3.14. A Block of small sized house type ... 35
Figure 3.15. Different wall thicknesses ... 35
Figure 3.16. Erbil brick wall style ... 36
Figure 3.17. Roofing system (timber-reed-soil) ... 36
Figure 3.18. Oval shaped vault in semi-basements ... 37
Figure 3.19. Spherical vault used in baths ... 37
Figure 3.20. Internal room doors ... 38
Figure 3.21. Main entrance doors. ... 38
Figure 3.22. Windows above eye level ... 39
Figure 3.23. Upper window ... 39
Figure 4.1. Erbil house entrance transition zone ... 44
Figure 4.2. Erbil vernacular house entrance gate. ... 45
Figure 4.3. Erbil vernacular house recessed entrance gate. ... 45
Figure 4.4. Erbil citadel town alleyways ... 47
Figure 4.5. Houses with preferred orientations ... 48
Figure 4.6. Houses with not preferred orientations ... 48
Figure 4.7. Wind direction in Erbil ... 49
Figure 4.8. Wind movement in alleyways ... 49
Figure 4.9. Doors Ventilation ... 50
Figure 4.10. Windows opened onto the courtyard ... 50
Figure 4.11. Shows the Windows ventilation mechanism ... 51
VIII
Figure 4.13. Alleyway section ... 52
Figure 4.14. Courtyards sun exposure ... 53
Figure 4.15. Overhang (Shanashil) ... 53
Figure 4.16. Rewaks ... 54
Figure 4.17. The Iwan ... 54
Figure 4.18. Shading device used on windows ... 55
Figure 4.19. Lighting through courtyard ... 55
Figure 4.20. Small sized windows on outside façade ... 56
Figure 4.21. Windows are in the outer edge ... 56
Figure 4.22. Inclined upper window... 57
Figure 4.23. Brick wall thickness ... 58
Figure 4.24. Roof composite ... 58
Figure 4.25. Vault roofs ... 59
Figure 4.26. Effect of water on air cooling... 59
IX
ABBREVIATIONS BC: Before Christ
Co: Celsius degree centigrade Km: Kilometer
M2: Meter square MM: Millimeters
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1. INTRODUCTION
1.1. Introduction to the Study
Energy consumption irregularly leads to energy sufficient in the near future. In order to reduce energy use, it’s needed to be found out the energy use fields. According to the statistics in the world more than %40 of energy is used in construction and buildings. More than %80 of energy is used during operating of buildings and nearly %20 is used during construction (Liu et al., 2010). The new building technologies is causing more energy consumption in buildings, new trends of architecture and different high tech forms made architects far from the surrounding environment. Most of the new built buildings are foreign to the environment and human’s natural life, human life has become more dependent on machines and destroyed the nature.
Emergence of environmental pollution caused by industrialization and energy crisis in 70s have directed many countries to look for new concepts (Özen, 1999).In the last decades there is a new trend of construction and architectural design due to more sustainable and environmentally oriented friendly buildings. One of the most important issues in the world is the energy consumption, which nowadays is one of the topics on the agenda of the most world leaders also. The important topic which gathers most of the world leaders in the same place to discuss is climate issues.
With the rapid growth of Erbil city, many architectural issues faced danger of disappearance. Loosing aesthetic identity and climate responsive properties of most the buildings in Erbil built environment. Construction thousands of houses as gated communities and individual builders which most of them were copy-paste designs from different regions and countries not suitable for the Erbil Environment and culture. This research try to find out the architectural design and construction problems, then try to determine the outline of the problems to suggest solutions to mentioned issues.
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1.2. Problem Statement:
The contemporary built houses of Erbil are lack of ecological or environmental considerations, so they cannot provide a comfortable internal temperature, so the inhabitants use mechanical instruments to compensate the loose of energy by consuming more fuel or other types of energy.
The problem is not just limited to one building element, it’s related to an architectural design from its inception which is the critical point to perform a building ecologically successful. The plan shape, orientation, openings, materials and the thickness of the walls are all the main strategic steps all which are related to each other to provide a comfortable inner temperature.
The elements or the strategies which are used in vernacular houses as solution to the climatic problems have disappeared in contemporary buildings which are very simple and can achieved easily in new buildings.
1.3. Purpose of the Study
The purpose of this research is to find out the environmentally used strategies which are used in Erbil vernacular houses, their purpose of using and also the techniques used during implementation.
Analyzing these strategies to be used in modern buildings with simple modifications without losing their ability to perform as ecological element. Climatic responsive elements will be described and defined in term of their ecological performance.
1.4. Scope of the Thesis
This thesis focuses on the vernacular houses in Erbil city, the houses inside the citadel town of ancient historical citadel. Architectural design strategies which used to provide a comfortable inside temperature will be analyzed. There are different methods to make buildings to be mentioned ecological and environmental according to design strategies, materials used and the techniques. The micro climatic elements inside each block of the settlement and inside the buildings are taken to be studied.
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The study location is considered as dry summer Subtropical region, so the vernacular houses must be studied according to climatically dry hot conditions.
The climate responsive elements in the vernacular buildings studied as a quantitative approach. The research focused in detail; the shape, location according to the façade, and the size of elements which used as solution to the climatic problems in hot-arid regions.
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2. LITERATURE REVIEW
In this session the previous researches on the ecological architecture in general and studies on vernacular architecture are reviewed. Then there is a brief review on the studies on climatic responsive elements used as environmental response in vernacular architecture and those elements in hot arid regions especially in middles east. At the end of the session there is an introduction about Erbil city and housing stock in Erbil city.
2.1. Ecological Architecture:
In a planet which the energy sources are going to be consumed and the life of millions of human, animal and plants are in danger as a result of unplanned using of energy.
Using energy in construction area is a continuously debated subject around the world in field of energy consumption. Reducing energy consumption in construction areas leads most of the researchers to work on it, to present solutions to the world.
Construction field especially building construction is the first in energy use among all other fields like industry, agriculture, commercial, etc… High raised building, new materials and new designs lead to use more energy as operation energy.
According to the statistic data’s gained by the research institutions the energy expenditure in building sector is the one of the high level rates of a total energy use in the world as shown in figure 2.1. The energy use in buildings.
Figure 2.1. Basic consumption sectors as shown in the energy statistics.
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The first step to reduce the energy consumption in construction field is the principles of ecological designs or environmental friendly designs. Ecological design or ecological architecture is one of the most popular issues in design around the world. In the modern day with high construction techniques the principles of the ecological building or environmental buildings have disappeared or the green and the ecological building principles erected as a decoration not functionally just aesthetics and fashion.
This chapter will review the previous researches and works on the ecological design criteria and studies on Erbil vernacular houses.
According to (Baran et al. 2011) the outline of the “ecological design criteria are components that have multiple directions and variability with respect to the current situations.” “Ecological design is sustainable systems, consistent with ecological principles, which integrate human society with its natural environment for the benefit of both.
In many ways, the environmental crisis is a design crisis. It is a consequence of how things are made, buildings are constructed, and landscapes are used” (Baran and et al., 2011). The other name of the environment friendly buildings is sustainability which was discussed in 21st century. According to some of the researchers the sustainability as an implementation was not new, (Manioglu and Yılmaz 2008) believe that “Sustainability, which is presented as a 21st century concept, has been in fact applied since Vitruvius wrote his books and was realized spontaneously in traditional architecture”.
The other terms used to define the buildings with effective climatic performance is bioclimatic building. “Bioclimatic design, by definition, satisfies the needs of human beings (thermal, luminous and acoustics). It considers climatic conditions, uses techniques and materials available in the region and attempts to integrate the building with its surroundings. Moreover, bioclimatic design relies on building physics, which is the ability and knowledge of how to allow sunlight, heat, and airflow through the building envelope when necessary, at certain moments of each day and month of the year” (Anna-Maria 2009).
A design with consideration of environment and social context of the region is a must be done issue nowadays, otherwise the surroundings and the environment will be destroyed. “If we wish to exist in harmony with our environment, we must do by choice
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what our ancestors did out of necessity, ‘design with the climate and with a sense of place”. If we ignore this, we miss out on many sustaining qualities of the natural context of site and surroundings (Oktay 2002).
2.2. Vernacular Houses
Under this subtitle the definitions and characteristics of vernacular buildings in previous works will be cited. The term of vernacular which at the same time means local building is defined as “is a term used to categorize methods of construction which use locally available resources to address the local needs” (Priyaa et al. 2012).
The buildings which are not designed by a foreign designers , but “are those constructed by local people and by using local materials and take the local climate in to consideration are the best samples of real ecological and sustainable buildings” (Safari 2013). The buildings are constructed by local people, “It is considered self-building; non-professional buildings are built by families and tribal members (Naciri 2007- Abdulkareem, 2012). So they are not designed in professional process. “The vernacular building construction techniques and specifications are more based on knowledge achieved by trial and error rather than conventional practices” (Mahapatra and Atreya 2011). Since they have an experiment with the surrounding, “Vernacular architecture sets an example of harmony between dwellings, dwellers and the physical environment” (Priyaa et al. 2012). “Sometimes, it is also found that some of the vernacular architectures are not climate responsive. However, in these architectures, cultural and social setup is the deciding parameter and overshadows the climate oriented features” (Jeffrey 1996- Ratti et al. 2003).
Since they are based on trial and error, “Vernacular architecture results from long-term growth and is part of traditional popular culture; therefore vernacular architecture is considered well adapted to the natural and social conditions of a specific location in which it exists” (Nguyen 2011). Vernacular architecture is not emerged from another period of time or another place with different climatic and cultural aspects. “Vernacular architecture evolves over a long time to reflect the environmental, cultural and historical context of that time period. It refers to that type of architecture which is indigenous to a specific time or place (not imported or copied from elsewhere)” (Priyaa et al. 2012).
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“The local builders and residents always try to amalgamate the climatic constraints, culture, social, economic and religion, while constructing these built environment with available resources and affordable technology” (Dili et al. 2010- Tassiopoulou 1996). So they are suitable with local climate and social characteristics. “Most of the vernacular architecture responds to the regional climate” (Albatici 2009). “People select those environments that suit them, that are congruent with psychological and socio-cultural aspects of their behavior” (Rapoport 1980).
“The familiar elements of regional architectural styles (verandahs, balconies, courtyards, shutters and such) are created to use the sun for warmth and light and to create shade and breeze for cooling. Climatic design lessons can be learned and inspiration can be sought by observation of the long tradition of vernacular architecture” (Indraganti 2010). “Process should be discussed in a holistic way. In other words, climatically responsive design, selection of materials and building techniques must be evaluated together and the final product should perform well during its whole service life” (Manioglu and Yılmaz 2008)
The geographical boarders of a society can be determined with an analyzing process of vernacular architecture, since “this type of architecture addresses the local climate constraints and shows maximum adaptability and flexibility. This provides uniqueness to these vernacular architectures and is often used as a symbol to represent a particular community or cultural setup” (Singh et al., 2010). Disappeared architectural and cultural values can be obtained again “Through re-assessing our traditional dwellings under an ecological prism, we appreciate the wisdom embodied in the vernacular architecture in its relation to nature and its distinct advantage in low energy density. Unfortunately, those potentials remain unknown or neglected. Nowadays, ecological and environmental awareness in architectural design and planning cannot be just a slogan or fashionable term. It has a real influence on our living environment. It is not enough to keep discussing architectural style, form, and genre. Now we have to allow ‘‘environment, energy and resource’’ to become genuine topics in the architectural field, for the sake of a more rational relation to the natural environment in which we exist, work and create” (Renpin and Zhenyu 2006). “The traditional architecture had given us excellent techniques which are climate responsive in nature.
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The principles which were used in traditional buildings can very well be implemented in the modern buildings so as to produce energy less consuming buildings and if these principles are sensibly adopted in modern buildings it is possible to build sustainable buildings for future” (Priyaa, et al., 2012).
In Middle East especially in the regions far from the sea which they are defined as hot arid areas, ventilation and cooling is the main obstacles against the internal comfort of the houses. The vernacular architecture of the Middle East and North Africa is especially well-suited to protect its inhabitants from the weather conditions found in a hot, arid climate (Naciri 2007).
2.3. Climate Responsive Elements
“Bioclimatic design, by definition, satisfies the needs of human beings (thermal, luminous and acoustics). It considers climatic conditions, uses techniques and materials available in the region and attempts to integrate the building with its surroundings” (Maria 2009). “Climatic design lessons can be learned and inspiration can be sought by observation of the long tradition of vernacular architecture” (Indraganti 2010).
The climatic responsive elements used in hot arid regions in previous research will be summarized. The elements and strategies used to perform the buildings better in climatic issues studied by researchers and categorized as protection from the sun and benefit from the sun and wind and ventilation.
Keshtkaran, 2011 states that “The town plan and alley ways used as a climate strategy to prevent from the extreme weathers, the narrow sidewalks with high walls on both sides are completely in the shadows. Roofed sidewalks (Sabat) help keep the sidewalks in the shadows”
Narrower streets also reduce the daylight component from direct solar radiation in the streets and building interiors, which is quite high. Narrow streets also protect the semi outdoor spaces from hot breezes. (Indraganti 2010).
One of the other elements which used especially in hot arid region as climatic solution is courtyards which “In Old houses was the center and heart of the building. Central courtyard with porch on each side was the features that were seen in past Iranian architecture. Also the courtyard was a space for various ceremonies such as religious rituals, weddings and family gatherings” (Nazidizaji and Safari 2013). “Central
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courtyard is symbol of settlement between human and environment which is used in the case study. Although these courtyards are the climatic answer to the open space of the house” (Roodgar et al. 2011). “In hot and dry climate, the most preferred plan type is the courtyard houses. In order to minimize the area affected by the solar radiation, compact forms are chosen” (Manioglu and Yılmaz 2008). “The courtyard was an energy efficient option as a low-rise building with variations to its energy performance from climate to another and depending on the configuration of other factors” (Aldawoud 2008). “The courtyard is an excellent thermal regulator in many ways. The heat gain from the sun will be more in the upper part of the courtyard. This makes the air in the upper part of courtyard warmer and lighter, causing the air to move upwards. Thus a low pressure develops in the courtyard and it induces an air movement from outside, through the surrounding spaces” (Dili 2010). “Houses with surrounded central yards are the most beneficial form for decreasing the exposure to harsh weather conditions, especially in hot, arid regions and in deserts” (Keshtkaran 2011). “The courtyards are surrounded by high walls that provide shade for the dwellings in the summer” (Baran et al. 2011). Also the “High walls closing a yard Protection against wind” (Canas and Martin 2004).”Courtyard has been used for long in Iranian traditional and other hot-arid regions’ architecture. In addition to protection, helping the building residents’ security and cultural-social events, a courtyard creates a small, cool and humid microclimate inside the building which reduces the energy required for cooling” (Khalili and Amindeldar 2014).
‘Natural ventilation of the building is needed to avoid over-heating during the day” (Bodach et al. 2014). “Courtyard system ensures ventilation through the building even during the calm outdoor conditions” (Priyaa et al. 2012). “Air exchange and natural ventilation are key elements used to control the temperature of vernacular homes” (Zhai 2010).
The most important climatic elements in hot summer regions are the shading elements. There is varies shading elements used in vernacular houses in hot regions. “Wall shading can reduce solar heat gain significantly using roof overhangs, window shades, awnings, a canopy of mature trees, or other vegetative plantings, such as trellises with deciduous vines. Shaded openings in the envelope during hot weather will reduce the penetration of direct sunlight to the interior of the building” (Okba 2005).
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The courtyard is shaded and hence it delays the heat gain and keeps the interior cooler. (Priyaa et al. 2012). “By arranging those forms with courtyards, shady areas can be obtained In courtyards, with the help of water and plants for evaporative cooling, the floor temperature can be minimized by the high walls surrounding the courtyard, shady areas can be obtained and the open areas can be used during the day” (Manioglu and Yılmaz 2008). “A large roof overhang of minimum 50 cm protects the walls from the heavy monsoon rain and avoids solar penetration of the facade during summer” (Bodach et al. 2014). ‘‘Eyvan’’ and revak, semi-open areas, are used to create shady and cool living spaces during the day” (Manioglu and Yılmaz 2008). Extended roofs and overhang on windows not only protect the wall from crumbling due to rainwater but also provides shading. (Singh 2011). Small windows Protection against solar radiation (Canas and Martin 2004). This courtyard primarily provides light besides used as an open space for number of other activities like cooking, sleeping, working, playing, gardening, and worshipping. (Priyaa, et al. 2012).
The other strategy which used in vernacular houses to protect from the extreme weather is thick walls with proper materials. “The aim of this strategy is to protect the interior of the building from the extreme temperatures because solar gains can be absorbed into the mass” (Canas and Martin 2004). “The thermal mass of the external walls and roof, which dampens the large fluctuations of external temperature” (Cardinale et al. 2013). “The rate of heat flow transmitted through exterior wall from the outside hot air to the inside air is proportional to the air temperature difference, area of the wall, and rate of global heat transmittance that can be determined from an analysis of the components of the total resistance to heat flow” (Okba 2005). “The exterior walls can be up to half meter thick which leads to a high thermal mass of the building” (Bodach et al. 2014). “The time lag of these walls is high; they store heat during the daytime and radiate it into the room at night when the outside temperature is below the comfort range” (Maria 2009)
“The thermal insulation in buildings is achieved by the effective use of materials and the techniques used in the construction of walls and roof” (Dili 2010) “Heavily insulated roof covering materials of the traditional dwellings modifies heating effect of sunlight as well” (Sozen and Gedık 2007). “Timber being a bad conductor of heat does not allow the horizontal surface to gain any heat throughout the day” (Priyaa et al. 2012)
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“Domes & vaults which are represented in terms of construction methods used historically, allow more natural ventilation in the higher space. It creates 24 h comfort inside. It also transfers heat more efficiently” (Abdelsalam and Rihan 2013)
The semi-basement is a room entirely underground whose roof is a few meters below surrounding ground level. The temperature of semi-basements walls, floor and roof is far less than outdoor air temperature. Additionally, in at a definite depth of the earth, its temperature remains constant and the variation range gets nearly zero. This rule is highly regarded in cellar placements underground. The basement was the only space in which the temperature fell within (or possibly below) the comfort zone. “This makes it clear why basements and underground living rooms were traditionally used as alternative living spaces” (Khalili and Amindeldar 2014)
Using of vegetation and water as a cooling strategy in houses is not new. It’s widely used in vernacular houses beside the other strategies. Mostly used in courtyards and houses surroundings. Plant coverage is very important for the structures in hot and dry climates, it…
• Reduces the direct sun light and its reflection. • Shadows the roof, walls, windows and the yard. • Reduces the dust around the building.
• Slows down the undesirable wind around the structure. • Increases the wetness in dry climates.
• Decreases the temperature around the structure.
“The pond in the yard and plants in the garden help circulate temperate air in the house” (Mohammadabadi and Ghoreshi 2011). “In the courtyard a pool of cool air is retained as this is heavier than the surrounding warm air” (Dili 2010).
Where creating a space with trees and decorative pool, safe from the warm winds the sweltering sunshine was the best reason for building a courtyard in the center of the house. and also using of vegetation as a shading is very effective on the entire temperature as (Roodgar et al. 2011) mentioned in a study which take Kashan/Iran as a case study states as “Sarabestan decreasing thermal exchanging in desert that was a small garden built alongside the house and had a positive effect on the climate of the house” One major reason of the existence of pool of water, trees and plants in most
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courtyards in this region is to increase the air humidity (which is crucial in hot and dry regions) and make the indoor spaces more moderate. (Khalili and Amindeldar 2014)
2.4. Erbil
2.4.1. Location of Erbil
Erbil is the capital city of Iraqi Kurdistan region and it’s the biggest city which placed in the north of Kirkuk and west of Suleymaniya and east of Duhok and Mosul.
Erbil is located North of Iraq (Iraq Kurdistan region) eastern south of Turkey, West of Iran (Figure 2.2. shows the location of Erbil in Iraq) with Latitude: 360.12’, Longitude: 440.04’ and Altitude: 470 m.
Figure 2.2. Location of Erbil in Iraq 2.4.2. History of Erbil
Erbil is the oldest continuously inhabited city, according to most of the historians the age of Erbil citadel town is more than 6000 years , which continuing as a living area in different history periods (Figure 2.3. Erbil Birds eye view). (HCECR, 2012).
Figure 2.3. Erbil Birdseye view
Iraq Erbil
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According to the (Encyclopedia Erbil 2009) Human beings have lived in Erbil since 40000 – 60000 years B.C according to the archeologists who found in Kurdistan caves (Figure 2.4. Shaneder caves) which they believe to be livable since 60000 years B.C. The remains of ten Neanderthals, dating from 35000 to 60000 years ago, have been found within the cave.
Figure 2.4. Shanidar cave
Erbil has always been a central meeting point for different civilizations throughout history including the Ubaid culture, the Sumerian, Akkadian, Assyrian, Median, Achaemenid and Sassanian empires, the Ommayad and Abbasid caliphates, the Mongol and finally the Ottoman empires
The present Name of Erbil is derived from The Assyrian Word “Arba-Illu” Meaning “Four gods” other Derivative Names include: Abailu, Arabales, Arbira and Ubri-Lum. (HCECR, 2012).
The oldest part of the city is the ancient citadel, whit is a wide housing area with more than 500 houses, their facilities and public services. The districts surrounding the citadel are also the oldest parts of the city after the citadel (Figure2.5). The houses are constructed with materials which can be provided in the surrounding regions easily and with less effort.
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Figure.2.5. Erbil ancient citadels urban Plan
Source: Erbil_Conservation_Master_plan_Volume_1
The other oldest remained parts of the city is Choli minaret (Figure 2.6.). “The Choli minaret is from the 14th century and it is the last part of the old mosque “(Pavelka et al. 2007). The mosque is not remained nowadays. The minaret lost its upper part in the distant past
Figure 2.6 .Erbil Choli Minaret
16 -20 0 20 40 60 80 100 120
Erbil Climate Data 2014
max temp min temp Humidity Rain (Millimeter) Dew Point
2.4.3. Erbil Climate
Erbil's climate is dry summer subtropical, in which summer is hot and dry and the temperature is reaching high 43o in July and August which are the hottest months of the year. Winter is cold, in January the temperatures drop to sub-zero degrees. (Figure 2.1.). With drastic temperature differences between day and night. (Omer 2011; Muhlis 2014).
Figure 2.7. Average climate data for Erbil for 2014
Source: Erbil general directorate of metrology
2.3.4. Population of Erbil
Erbil is one the most lively cities in the Middle East which is growing continuously at a rapid pace. The increase of population of the city caused by its relatively large families which consists of five members on average and the increased migration from the village and other cities of the region to Erbil seeking prosperity in the developed Erbil.
According to IOMs Statistic Data, Erbil city has seen an increase in population from 450,000 in 1977 to more than 1.54 million in 2012, which has added more pressure to the housing sector (IOM, 2010; Abdulazeez, 2015).
2.3.5. Socio-Cultural context
Mesopotamia is one of the oldest civilizations in history, dating back more than 6,500 years. It was located in modern Iraq and is known as the cradle of world civilization. Mesopotamia was the center of several civilizations, starting with the
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Sumerians in the southern part of the area around 3100 BC and followed by the Babylonians and Assyrians (Gascoigne 2001).
Kurdistan is a region with a diverse topography and hot, arid climate that has been dominated by many different empires over the centuries. The Kurds are a primarily tribal ethnic group that span the borders of several countries, but maintain their own culture (Abdulkareem 2012).
The majority of Kurdish people are Muslims (Islam spread into Kurdistan in the seventh century CE) (Cavendish 2006). Jewish Kurds were once populous in Iraq, but their presence decreased drastically after World War II, when most of the Jewish population immigrated to Israel (Cavendish 2006). The rest of the Kurds practice varied ancient religions: 2% observe Yezidism, a religion that combines aspects of Islam, Judaism and Christianity (in west and west-central Kurdistan); 13% practice Yarsanism or Ahl-i Haqq (in southern Kurdistan); and 20% practice Alevism or Kizil Nash (in western Kurdistan and the Khurasan) (Cavendish 2006). Very few Kurds are Christians (only 3% of the total Iraqi population is Christian, most of them Assyrian) (Cavendish 2006).
The Christians live in Ainkawa (northern part of the city), the Yezidi people live in North West towns of Erbil, the Turkmens and Kurds live in the center of Erbil in quarters surrounding the citadel. The people emigrated from the rural towns and villages to the city live in the suburb quarters.
2.5. History of Housing Development in Erbil city:
The houses characteristics have changed upon economic, political and cultural alterations. According to the development of economy, political situation and political perspectives of faculty power the houses and buildings have been modified.
It’s divided into several remarkable periods a number of which are listed below.
2.5.1. Before 1930 housing development
Traditional ancient city of Erbil is one of the oldest continuously inhabited urban settlements in the world (Grant, 2004; Yildiz, 2004). Before 1930s the Erbil house were
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composed of the citadel town and few houses around it which are vernacular Erbil houses samples. Figure 2.8. Shows the urban plan of the Erbil settlement before 1930.
The characteristics of this houses and quarters are mainly made of mud with brick walls, short span timber roofs and mud roofing and narrow alleys between houses and also they are known as courtyard houses. The thick walls and small openings to outside are distinguished characteristics of this periods’ houses.
Figure 2.8. Urban plan of the Erbil settlement before 1930.
Source: HCECR
2.5.2. 1930-1980 Period Housing Development
In the early twentieth century, especially after British occupations during World War I, a modern city was introduced as an instrument of colonial control. The industrial capitalism and its social and cultural effects provide the basis for notions of the modernism (Gunter, 2004). The internal courtyard continued to be used until it totally disappeared in the 1950s (HCECR, 2009).
The main characteristics of houses of this period are large windows with using different materials from the traditional houses. The houses didn’t have enough climatic property as the courtyards not studied enough for climatic purpose, the windows are large which its disadvantage in heat gain and heat loss, the materials had no good performance in insulation and they didn’t provide good privacy as in vernacular house before (Figure 2.9).
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Figure 2.9. The Style of House Period (1930-1980)
Source: Baper 2011
2.5.3. 1980-2003 Period
In this period Iraq and Kurdistan suffered from many international and internal economic and politic problems which started from 1980s and continued with Gulf war and after that with embargo which affected the economy of Iraq which directly affected the architecture issues. In this period the houses are so simple with poor decorations outside with cheap materials mostly cement plaster used (figure 2.10).
Figure 2.10.The Style of House Period (1980-2003)
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2.5.4. After 2003 Period
After falling Saddams regime and developing of economic situations in Kurdistan, the architecture and house designs stepped into a modern period with expensive materials and different outside façade decorations.The housing projects are divided into many categories in this period which are:
The luxury houses; the luxury villas and houses built by rich people (Figure 2.11.a & 2.11.b). 200-500m2 areas in Erbil with expensive materials especially high decorated facades outside and most of them with lighting and inside temperature comfort problems. The architectural styles are different each copy or reproductions from different countries.
Figure 2.11.a. Luxury Houses in Erbil
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The Gated communities: after fall of Saddams regime, the new trend started, many gated communities constructed in Erbil each one from different style and effected by different countries architectural styles instead of Erbil environmental characteristics (Figure 2.12.). Also they are named as English Village, American village, Vital village, Italyan City, German City, Lebanon Village and so on…..
Figure 2.12. Italyan city gated community
In this period also some Apartments constructed from 8-15 storey gated community housing projects which is new in Erbil. There is very few apartment projects in Erbil before this period (Figure 2.13).
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The house built by normal economy income people: this type of houses are similar to each other with restricted plot areas between 100- 150 m2 they are known among people as 100 house or Sulaimani1 Style (Figure 2.14.b) with low climatic performance constructed with hollow concrete blocks and inside plastered with gypsum.
There is just one outside façade for the houses are row houses plastered with mortar or finished with natural stone according to the owner’s budget (Figure 2.13.a).Most of the houses which are built by rich people for rent are in this type.
Figure 2.14.a.100m2 row houses
Figure 2.14.b. 100m2 mirrored plan
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In this chapter the previous studies on the vernacular architecture as all has been reviewed. This review shows that most of the vernacular houses in the hot arid region used courtyards as plan type for better perform as climatic and social response. In this review observed that the strategies that used as climate responsive elements in vernacular houses in hot arid regions are similar which answers to climatic, cultural, social and religious needs.
The other part is a brief history of Erbil and the housing development chronology of Erbil. The geographical and climatic characteristics of Erbil is shown with figures and data obtained from different sources. The next chapter will describe the general characteristics of the Erbil vernacular architecture which will be analyzed in chapter four in terms of climatic responsive elements.
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3. ERBIL VERNACULAR ARCHITECTURE
This chapter begins with the history of the case study with graphical data and architectural drawings of the Erbil vernacular houses inside the citadel town. The vernacular houses of Erbil citadel town are the oldest houses in the region and also in the world which are still inhabited. The climate of Erbil is hot-arid area, so the house must have a good solution for the cooling and heating systems since there weren’t any mechanical solutions in past. This chapter is a brief introduction about the vernacular houses of Erbil citadel with high performance of climate responsive elements.
3.1. Erbil Settlement
Erbil citadel thousands of archeological tells in Mesopotamia, but what makes Erbil citadel unique is that it seems to have been continuously inhabited from the beginning up to the present. The citadels written history starts 2300 BC (HCECR, 2012) and until the proposal large-scale archeological excavation is undertaken.
Erbil is situated in a fertile plain between the great and little zap rivers, with a backdrop of the Zagros mountain range, and lies at the crossing of important historical routes from Iran to the Mediterranean, and from southern Iraq and the Gulf to Anatolian and Central Asia. It is this strategic location which has assured its continuing importance through the centuries, coupled with the abundance of its agricultural hinterland. Erbil city.
Erbil in the second half of the third millennium it’s recorded as Irbilum and in slightly later Sumerian texts as Urbilum five hundred years later, the name appears as Urbel. In the late second millennium, the name appears as Arbail. In the Neo-Assyrian period this was often written in a scribal shorthand combining the cuneiform sign for “4“(arba) with the sign for “god” (ilu), utilizing the phonetic values of these signs in Akkadian to create the name Arbail.
In the Achaemenid period the name appears as Arbila, in classical sources as Arbela and thereafter as Arbil, Irbil and Erbil. Kurdish settlers named the city Hewlêr, which refers to the "Temple of the Sun" in the Kurdish language (Gordon 2008).
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Figures 3.1. Location of Erbil old settlement
Source: HCECR
3.2. The citadel mound
The citadel mound is shaped like a shallow bowl, with the highest points on the north-east and south-west edges, which it’s up to 32 meters high. There are 11 hectares enclosed by perimeter façade and it measures 15 hectares at the base (HCECR, 2012). The mount is entirely the result of human activity and the highest represents the natural built-up resulting from the accumulation of the historical layers throughout the millennia, as each replacement house was built on the leveled remains of the house which preceded it. So it’s believed to be big voids under the exist mound with archeological remains.
Figures 3.2. Erbil citadel mount. Source: Google earth
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3.3. Alleyways
The alleys inside of the citadel town are narrow and were to be used for coach and pedestrians not cars or modern vehicles. The alley ways are different in width according to their functions. The figure 3.3 shows the different width of the alley ways and streets inside the town.
Figure 3.3. Erbil citadel alleyways
Source: HCECR
3.4. Mahallas (quarters)
The town divided in two three quarters (mahallas), it’s not divided physically but it’s divided up to the inhabitants as follow:
Saray
Located in the eastern side of the town and so-called because it included the saray of the southern gate. It was largely occupied by the rich families (chalabis) and government officials and notables (aghas). (HCECR)
Takya
Occupied the central and northern part of the town and so-called because it contained several takyas for derwishes. The house are not so big and they are mostly one floor house, simple in internal decoration and lack number of rooms.
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Topkhana
Occupied the western side and inhabited largely by craftsmen and farming families. Its name suggest that it contained cannon do defend the town against attackers. It is said that this cannon was made around 1820 by a certain Usta Rajab Al-kurdi of Rawanduz. (HCECR)
Figure 3.4. Erbil citadel quarters.
Source: Abdulkareem 2011
3.5. Dating of the Houses
According to the HCECRs publications on Erbil Vernacular houses inside the Citadel under the titles of (highlights of Erbil citadel) the house are categorized according to their built date:
- Earlier Ottoman period (1750 – 1880). The earliest houses only had small ventilation windows high in the walls and the rooms were dark inside. This resulted in large expanses of the wall which could be display ornamental brickwork. Other features of early houses are triangular-headed niches high in the wall opposite the entrance door and two tiers of rectangular-headed niches in the lateral walls. Many have arched niches in the corners of the room next to the door and double gypsum shelves for displaying brassware.
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- Late Ottoman period (1880 – 1918). Houses built after 1880 have arched niches in the walls and windows to light the rooms. The grandest mansion can have richly decorated interiors. The windows can be protected from the sun by porticos supported on timber columns and a few have impressive arcades of Mosul alabaster. Windows have iron grilles with knobs at the intersections or decorative grilles.
- Post- Ottoman period (1918 – 1960) Post-ottoman houses have a functional design and have large, tall windows and ventilation windows with a horizontal profile. Some of them are roofed with jack-arches supported by iron I-beam and porticos supported on iron columns. Window grilles are plain and set within the timber windows. Internally, niches have segmental-arched heads. Parapets can have panels of diagonally-set bricks. Street and courtyard doors can be set within deep chamfered reveals.
- Modern period (1960 –1986) Very few houses were built in this period. Those that were are all low and have wide windows. Internally, niches are a vertical rectangles. It’s the period of stagnation which there is new built house and the house also built after this period are mostly renovation and construction in destroyed houses no new plots.
- Squatter shacks (1986 –2006). Squatter buildings are mostly built out of old bricks and are characterized by poor construction. Mud bricks were also sometimes used, as well as concrete blocks. All herringbone brickwork dates to this period. Within the revitalization process, such impermanent buildings will be replaced with the structures designed in accordance. - Without underestimating the aesthetic, historical and cultural values of
traditional architecture, I feel that it is today crucial to re-survey vernacular architecture in light of up-to-date environmental and ecological concepts. - In 2007 the governorate of Erbil transferred all the habitants of the citadel
town to another place and the citadel labeled as buffer zone. The revitalization works started.
- The revitalization master plan prepared to renovate the citadel houses and reconstruction the destroyed buildings under the recommendation and observation of UNESCO. Erbil Citadel House is in World Heritage List now.
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3.6. Housing Typology
Before of 1930s of the last century, the citadel consisted largely of traditional courtyard houses- just over 500 in all. In this number there were nearly 30 large palace-like house that were mostly located on the peripheral wall but some were inside the town proper as shown in figure 3.5.
Figure 3.5. Palace like houses in Erbil Citadel
Medium-sized houses numbered about 120, the figure 3.6. Shows the medium sized houses in the citadel which occupied the central part of the citadel.
Figure 3.6. Medium sized houses in Erbil Citadel
Smaller houses of poorer families numbered about 350. The small house also have small courtyard and most of them are one floor, there is limited number of rooms and the size of the rooms are small (figure 3.7) (HCECER)
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Figure 3.7. Small sized houses in Erbil Citadel
All these houses, large and small, had open courtyards and were constructed with clay brick. Timber joists used for roofing and brick vaults for roofing of semi-basements. The inside walls were plastered in gypsum and had numerous niches and shelves, often decorated with colorful patterns and features.
The typical ideal plan of a traditional house in the citadel is a regular geometric shape (figure 3.8), a rectangle or square, composed of one or two floor of rooms looking onto the open courtyard. In fact, very few houses achieve this ideal plan although some come close.
Figure 3.8. Regular shape of the houses opened to courtyard
The entrance, direct or broken, always led an open courtyard first. From this courtyard steps led one either down to a semi-basement or up to upper floor which nearly has an arcaded or colonnaded terrace or Tarma (figure 3.9).
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Figure 3.9. House plan showing the entrance and division in courtyard
There were other variations which resulted from constrained given by the shape of the land plot. If the frontage was wide, then the courtyard was placed in the middle with its long axis (if rectangular) perpendicular to the alleyways. In such a case the plan was often split into two mirrored arcades with several rooms on each side the room size are small, the courtyard is small the rewaks, the canopies or any other shading techniques not used since no need for shading the inner walls or prevent form sun expose its already shaded (figure 3.10.).
Figure 3.10. House plan shows the courtyard in the middle
Another variation was a mirrored split of the plan into two similar houses (twins) but with one entrance which, in turn, split into two (figure 3.11). In such a case, the
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arcade in each house took an L-shaped arrangement. The upper storey was repeated with an arcade or a tarma.
A party wall was used to divide the twin houses. The house are not separated completely, they are used as a big family house which the same courtyard with semi-separated by a wall which sometimes are not very high as seen in the courtyard walls which separate the house from the public and other houses.
Figure 3.11. House plan shows twin house with the same entrance
3.7. Erbil Vernacular Houses Building Properties
Plans are variable according to the plot areas which s different according to the position of the plot on the town hill.
The houses which they are located in the eastern north especially in Saray quarter are bigger in size and they are with big courts inside and semi-basements also with definite iwans. The plot of the house is with large dimensions compared with other types and the courtyard dimensions are wide enough to provide preferred sunlight enter the house. The room dimensions are big and also number of rooms are more than other houses also mostly they have a large diwakhan room (guest reception room). These houses are inhabited by chalabies and aghas which they are merchants and government officers. Figure 3.12. Shows a block of large houses.
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Figure 3.12. A Block of palace-like house type
The houses which they are owned by the common inhabitants are smaller in plot size and contains of two or three rooms. These type of house plans are mostly on perimeter walls of the citadel (Figure 3.13).
Figure 3.13. A Block of medium sized house type
Houses with small plot size which represents low income families especially craftsmen and farmers which they were working in lands surrounding the mound below and live inside the citadel. The plots which located between the blocks also constructed by low income people as small houses (Figure 3.14.)
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Figure 3.14. A Block of small sized house type
The thickness of the walls are different according to the position of the wall inside the plan. The perimeter walls are thick enough in some place are lead to 1.8m, but in partition and other inner walls are 0.4m (Figure 3.15.).
Figure 3.15. Different wall thicknesses
The material used in walls in general is mud bricks which it’s available in surrounding lands and it’s plastered inside with gypsum which also it’s available in lands near to the citadel town by few kilometers. The outside surface elevation of house is not plastered or covered but it’s decorated with brick artistic which it’s recognized as Erbil style as shown in figure 3.16.
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Figure 3.16. Erbil brick wall style
Most of the roof of the houses inside the citadel town are constructed of multiple layer, the first layer is timber and a layer of reeds then a layer of mud or soil. The aesthetic of the ceilings is not neglected, the space between the timbers is equal and it give a nice pattern view to the ceilings (Figure 3.17.).
Figure 3.17. Roofing system (timber-reed-soil)
The other type of roofs are made of bricks as vaults especially in semi-basements (Figure 3.18.) and baths (Figure 3.19.). The vaults are made of bricks with an artistic work which need professional Ustas and masters to construct it, there is large spaces covered by the vaults with an oval shaped. In the smaller spaces the shape is spherical.
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Figure 3.18. Oval shaped vault in semi-basements
Figure 3.19. Spherical vault used in baths
The openings in Erbil vernacular houses have important role in climatic issues. Openings are located in the envelope to provide physical access to a building, create views to the outside, admit daylight and/or solar energy for heating, and supply natural ventilation (Okba, 2005). Traditional doorways to most of the houses and courtyards are a vertical rectangle with little decoration, but doors inside the courtyards are sometimes highly decorated (figure 3.20.), either with patterned brickwork or plaster.
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Figure 3.20. Internal room doors
According to (Khaznadar, 2010) the entrance widening the vision angle to maintain privacy especially for strangers. The entrance gates to the courtyards are recessed into inside (figure 3.21). The gates are opened to a courtyard or with a transition to the courtyard.
Figure 3.21. Main entrance doors.
The windows system of the vernacular houses inside the citadel are one of the distinguished characteristics of them, which they are provide privacy either climate comfort. The windows are small in size and divided into smaller parts, mostly made of wood and painted glasses can be seen a lot (figure 3.22.). They are small in size and located above eye level from the ground outside floors
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Figure 3.22. Windows above eye level
The other distinguished characteristics of the windows are the upper windows which they perform an important role in ventilation inside the rooms (figure 3.22.).
Figure 3.23. Upper window
This chapter was data collection process about the Erbil vernacular architecture which contains drawings and photos with their descriptions which it’s a preparation step to the next sessions. The houses main parts and the building element with their function and aim of use were described. In the next chapter the climatic responsive elements and strategies used in Erbil vernacular houses will be analyzed in detail.
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4. CLIMATE RESPONSIVE ELEMENTS IN ERBIL VERNACULAR ARCHITECTURE
This chapter will analyze the climatic responsive elements used in Erbil vernacular houses inside the traditional Erbil citadel town. The analyses are based on the drawings which are obtained from the (HCECR) with some details and categorizing by the author. Also photos obtained during site survey of the houses which were permitted by the officials to be visited, some of the houses are not permitted to be visited.
4.1. Methodology:
The data used in this research is obtained from different channels including the urban plans, floor plans, elevations, sections and detail drawings and photos with the statistic tables.
Most of the data obtained from the High Commission for Erbil Citadel Revitalization (HCECR), the other data obtained from different governmental sources, previous researches and field observations and works of the author.
- The collected data is analyzed in order to find out the main climatic characteristics and the techniques used in vernacular houses.
- The climatic elements are listed and analyzed according to their function, size, material and positions on façade surface.
- The evaluation of the drawings is based on the different passive heating and cooling laws, which are adopted in the world.
- The popular climatic strategies used in built environment in hot arid regions (Canas and Mart 2004 - Nguyen et al. 2011) are categorized as: (1) Town planning, (2) Building orientation and form, (3) Wind Factor, (4) Natural ventilation, (5) Natural lighting techniques, (6) Solar shading (7) High thermal mass and insulation by material (8) Evaporative cooling and using plants as cooling, (9) Earth cooling.
- The case study will studied according to the highlights those are mentioned above.
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4.2. Definition of the case study:
Vernacular houses in Erbil are traditional house in Erbil city especially inside the citadel and the quarters around the citadel. The oldest part is the houses inside the citadel town, the surrounding parts were built as a result of the population growth of the citadel inhabitants.
The citadel and the city built on Land known as Erbil plain, the plain is between two rivers which are the big and small Zab.
This research will focus on the houses inside the citadel town, which are around 500 houses mostly of one storey with a few number of two storey houses, they were inhabited till 2007 by common people until the government transferred them to other place in order to revitalize it.
The town is on the mound hill, which is believed to be an artificial mound not natural. The town has two main gates one from the south and south-east and the other from the north and north-west. Most of the houses are made of clay bricks which are available material in surrounding lands, they are good solutions of climatic problems with passive systems by using material properties. Also other material as timber and reeds which are used in roofing and natural stones which are used in some palace-like houses for empowering the basements and as stair and pavements are available in north and north east of the city.
The house are made by inhabitants as test error method so the house quality and the house size and climatic performance of the house is referred to the owner’s knowledge and economic and cultural level. Most of the house are open to in closed to outside, means most of them have courtyards but the court size and orientation depends on the plot size, location of the house in the citadel and the income of the family.
4.3. Ecological criteria:
This part will analyze the Erbil vernacular houses according to the ecological design principles which are categorized as; economy, socio-culture and environment. The city plan, used material and the socio-cultural aspects were taken in consideration or not. Also the elements used as solution or response to the extreme weather of the region will be analyzed.
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4.3.1. Economy
Economy is one the important criteria to determine a building as an ecologic building, since the directly affect the built environment and the specification of the buildings (Dumreicher 2008).
The expenses of the buildings are divided into two; construction and operation expenses. Reducing the expenditure of the buildings depends on the all process together means the construction budget and operation budget. Using local materials and design building with consideration of the local environment will achieve the goal of the reducing energy and that make the building more economic (Zimmermann et al. 2005).
Erbil vernacular houses are made of the materials from the surrounding lands. The main used materials in house are; clay brick which available in surrounding lands and can be produced easily and also can be transported easily. The clay brick furnace were present in near to the citadel. The straw which used as energy resource to burn the clay bricks also available in Erbil plain. The timbers and reeds which used in roofs also available in north of Erbil in mountain regions which it 30-50 km away from the citadel. The materials used are with effective thermal insulation property and the design strategies used in houses reduce the operation energy use of the houses. The important way to reduce total expenditure of a building is to reduce the operation energy use of buildings which can be achieved by selection the material and benefit of the climate elements. The vernacular house of Erbil are successful samples of using right material and using deferent strategies to protect from climate elements and take advantages from climatic elements such as wind, sun, rain.
4.3.2. Socio-cultural criteria
One of the criteria of a building to mention as an ecological design is the social factor. Since the building is built for people with some norms, religious and cultural principles. Every local region has different social context, which consist of many significant considerations to be taken as design criteria.
Erbil with all its ethnic and religious sects is a conservative city, in which family privacy is of prime importance and it is famous for hospitability which means that the houses needs a private gathering area. The courtyards are the private gathering area for the families which connect the inside inhabitants to the outside nature or weather
