Enerji Etkin Tasarımda Bir Arakesit: Toprak Örtülü Yapılar

Abstract

Bugün hızla azalan kaynakların yetersiz hale gelme durumuna cevaben ortaya atılmış olan sürdürülebilirlik kavramı gereği, yaşamımızın her alanında gelecek nesillerin mirasına dokunmadan kendini hayat boyu sürdürebilecek tasarımlar yapılması öncelikler arasında yer almaktadır. Buradan hareketle, yapılar da bu anlayışta inşa edilmeye başlanmış, ekoloji ve mimarlığın bir araya geldiği ekolojik mimarlık kavramı ortaya çıkmıştır. Ekolojik mimarlıkla birlikte, pasif solar enerjiden yararlanan enerji etkin yapılar insan yaşamına girmiş, geçmişte varolan örneklerden bazıları modernize edilmiştir. Bunlardan biri de toprak örtülü yapılardır. Bu yapılar canlılığın başlangıcından bugüne varolmuş, enerji kriziyle birlikte yeniden gündeme gelerek modern dönem yorumları ortaya çıkmıştır. Birçok yapıya göre nispeten daha sürdürülebilir olduğu düşünülen bu yapılar, geçmişten bugüne kullanılmakta olan örneklerle araştırma kapsamında incelenmiştir. Bu tezin amacı, tarihten bugüne toprak örtülü yapıların geçirdiği evreleri, bulunduğu dönem ile birlikte inceleyerek kronolojik bir gelişim diyagram ortaya çıkarmak ve incelenen örnekler ile literatür çalışmalarından edinilen verilerden yararlanarak toprak örtülü yapıların sürdürülebilirlik açısından yeşil çatılar için yol gösterici kriterlerini ortaya koymaktır. Tezin giriş bölümünde ekolojik mimarlık kavramına ve enerji etkin yapılar arasından niçin toprak örtülü yapıların seçildiği konusuna açıklık getirilmiştir. İkinci bölümde, yenilenebilir enerji ve enerji etkin tasarım kavramlarına değinilmiş, konunun anahtar kelimelerinin tanımları yapılarak enerji etkin tasarımın parametreleri ve enerji etkinliğin peyzajda yorumlanışı üzerinde durulmuştur. Bu yorumlama, ‘Sürdürülebilir Alanlar Girişimi’ performans kriterleri kapsamında gerçekleştirilmiştir. Üçüncü bölümde tezin ana konusunu oluşturan toprak örtülü yapılar derinlemesine incelenmiş, toprak örtülü yapıların tarihsel gelişimi bölgeler bazında ele alınarak yapım yöntemleri ve prensipleri ile malzemeleri belli bir sıra ile açıklanmıştır. Dördüncü bölümde ise derlenen bilgiler ışığında seçilen örnekler incelenmiştir. Aynı zamanda yerinde incelenmiş örneklerin kullanıcıları ile de görüşmeler yapılmış ve uygulamada eksiklikler olup olmadığı belirlenmeye çalışılarak, literatürdeki bilgilerin doğruluğu da test edilmiştir. Beşinci ve son bölümde de, bugün aynı mantıkla kendini savunan fakat uygulamada ve sürdürülebilirlik perspektifinden bakıldığında oldukça ayrı bir noktada duran sanayi ürünü modern çatı bahçeleri ile toprak örtülü yapılar çeşitli yönlerden tartışılmıştır. Çalışmanın sonucunda, bugün kentsel yeşil sistemin önemli bir parçası haline gelmiş olan yeşil çatıların düşünüldüğü kadar sürdürülebilir olmadığı anlaşılmıştır. Aynı mantıkla daha önceleri ortaya konulmuş toprak örtülü yapıların ise “Sürdürülebilir Alanlar Girişimi” kriterleri kapsamında değerlendirilmesi ile, çatı bahçelerinden daha sürdürülebilir ve ekolojik olduğu görülmüştür. Fakat bu yapıların da yoğun kent dokusu ile entegre olmasının bir hayli zor olmaktadır. Bu sebeple, yeşil çatı sistemlerinin üzerine gidilerek, yeşil çatı endüstrisindeki eksiklerin toprak örtülü yapı sistemlerinin deneyimlerinden faydalanılarak giderilmesi en doğrusudur. Bunun yanı sıra, yeşil çatı sistemleri revize edilerek, yeni ve sürdürülebilir, her bölge için ayrı tasarlanmış yerel ve daha doğal sistemler geliştirilebilir.

After oil crises and rapid urbanization, the supply of fossil fuels is shrinking. Access to fossil fuels, which have been the primary source of energy, is becoming both limited and expensive. However, dependency on these scarce energy resources has increased with the development of technology. In order to avoid a situation where the demand is greater than the supply, the concept of sustainability was introduced. This concept means to produce lifelong, self-maintaining designs in every area of life. In terms of economic, ecologic, and social sustainability, these designs should not touch the heritage of the future generations. Structures have emerged using this perception and concept of ecological architecture, which combines ecology and architecture. Ecologic architecture focuses on designs in harmony with nature, minimum damage to the natural resources when creating an artificial environment, minimum usage of resources and recycled plans and designs. Moreover, buildings built in this design make an effort to use renewable energies as much as possible like sun, water and wind energy. Along with ecological architecture, energy efficient structures that take advantage of passive solar energy have started to become popular. One of these energy efficient structure examples is the earth-sheltered house. Earth-sheltered houses have existed since the beginning of human life and have come to the forefront with modern term reviews after the energy crisis. These structures, assumed to be more sustainable than other structures, were examined and compared to similar examples and roof gardens in the past and present. Generally these structures were covered, which created the occurrence of a good thermal mass of the soil. At the same time, they generate new ecosystems in cities or sometimes continue the topography that is located in. With the synchronized growth of technology and urbanization, the use of green spaces on buildings has regained importance and are now called roof gardens. These systems use the same logic used in the sheltered houses, but they have some features that are not suitable for criteria sustainability. When the logic of the emergence of roof gardens is compared to FLL Guidelines, some disagreements are observed. However, it has become an important part of the urban green system. So, the question was asked what can be done to make roof gardens more sustainable? The origin of the subject was examined in order to find more natural and sustainable version of the roof gardens. The aim of this thesis is to present the historical evolution of soil covered structures as the basis for green roof and construction industry; and to reveal the guiding criteria for green roofs in terms of sustainability. Furthermore, we hope to create a guide book/reference. Construction techniques and the logic behind green roofs and earth-sheltered structures are examined and compared. And consequently, it is intended to be a guide to current green roof applications. The methodology of this thesis relies on an academic and popular literature review, correlation and interviews. Thus, these methods were followed respectively: A literature review was made about ecologic architecture, renewable energy, energy efficient design, eco-structure, energy efficient landscape design and earth-sheltered structures in detail. Furthermore, earth-sheltered structures have been investigated throughout history and analyzed based on layers. So, the criteria which are related to earth-sheltered structures and sustainability were determined and structures were evaluated according to these criteria. These criteria were matched with “The Sustainable Sites Initiative” parameters. So, earth-sheltered structure samples which are still available to use and additionally one of roof garden sample were examined and correlated according to “The Sustainable Sites Initiative” criteria and interviews with users during visits. By blending all of these studies, the conclusion was reached. In the introduction, the definition of the problem, the aim, scope and method of the study are explained in detail. The concept of ecological architecture and earth-sheltered structures and the viewpoint of Malcolm Wells, who is one of earth-sheltered structures pioneers, are described. The reason why earth-sheltered houses are selected from energy efficient structures and also the importance and the reasons for the selection of the selected samples are explained. There is also an explanation of the questions asked during a site visit and an examination of how those questions were prepared. Additionally, a schema is added at the end of this section as a summary of method. In the second chapter, renewable energy and energy efficient design concepts from past to present are explained. Parameters of energy efficient design such as location, direction, form and building envelope are described. The heat losses of earth-sheltered structures at various stages are also shown according to the building envelope. Then, a brief overview of eco-structures is provided. As a conclusion of this chapter, energy efficient landscape design is described as the main task of landscape for these type of structures. Earth-sheltered structures use soil and vegetation layer, which are the most important materials of landscape for the purpose of energy efficiency; keeping in mind the type, shape and height of plants, direction and velocity of wind, direction and angle of sun, and amount of radiation can be arranged. Starting from this point, selection of the right plants and how they should be positioned in a right way were explained. Interpretation of energy efficiency in landscape is focused on in more detail by defining keywords. This interpretation results from performance criteria of “Sustainable Sites Initiative”. Its guiding principles and application areas are identified in this chapter. Initiative discusses the sustainability on landscape basis and it has a very detailed scoring system. Analyzed samples were therefore rated in this scoring system and provided based on the numerical data of the comparison. In the third chapter, earth sheltered structures, which are the main subject of the thesis, are examined in depth. Plan types, advantages, disadvantages, components, construction methods, principals and materials of these structures are described in a certain sequence. Then, the history of earth-sheltered structures was described by considering their historical development based on location. Starting from caves to adobe structures and from there to the transition to earth-sheltered and then green roofs. This sequence is shown with a table. Construction methods and principals are explained in three parts respectively: Site planning which consists of topography, ground water table, climate, orientation and soil, planting and insulation. As mentioned in the previous section, planting is the most important factor that brings together earth-sheltered structures with the landscape design. So, planting has been divided into two parts in this chapter as earth-covered roof planting and external planting. Vegetation, which covers the structure envelope, uses for energy efficiency and thermal mass. And also external planting is used to improve energy efficiency. Vegetation and external planting are explained separately because they maximize together the energy efficiency of the structure in different way. Subsequently, insulation, soil and drainage are explained in detail according to materials. Also building materials and elements are described briefly. At the end of this chapter, the criteria used to evaluate the earth-sheltered structures were described according to “Sustainable Sites Initiative” criteria. Analyzed samples were rated using the chart that consists of “Sustainable Sites Initiative” criteria. The criteria contributed to the idea, which was concluded as a result of the study. The table is given in Appendix B. In the fourth chapter, six examples were examined in the light of collected information. Four of these examples are designed by Malcolm Wells, one is designed by Frank Lloyd Wright and the last one is a roof garden is designed by Michael Van Valkenburgh Inc. Three of them (first earth-sheltered office of Malcolm Wells’ in Cherry Hill, Locust Hill and Sidwell House in Raven Rocks) were analyzed where they are located and interviews were conducted with the owners of these structures. So the accuracy of the information in the literature was tested by determining whether or not there were deficiencies in the application. Information about the other three samples (Solar Hemicycle, Solaria and ASLA Headquarter) collected from reports, books and articles. The common feature of all these samples is that they are still in use and located in the USA. The reason is that the modern era interpretation of earth-sheltered structures are seen frequently, also the best-known examples, designed by pioneers of earth-sheltered structures are in the USA. Additionally, the structures that have benefited from the soil by starting from shelters in ‘Homestead Act’ era to basements in World War II era and to Lithospheric Living Spaces can be viewed respectively in this country. In the fifth and the last chapter, earth sheltered houses and modern roof gardens were discussed in light of various aspects. Studies have shown that roof gardens’ systems are industrial products and seem quite different in terms of materials and application from earth-sheltered structures when viewed from sustainability perspective. But earth-sheltered structures, which derived from the soil covered Scandinavian-type structures, maintain the continuation of the ecosystem materials. The construction of these structures, by combining thermal mass feature of soil and local-sustainable materials, makes a major contribution to the idea of these structures’ being more sustainable when compared to conventional structures and modern green roofs. They are more accessible because of the local and economic materials. In conclusion, roof gardens, which have become an important part of the urban green network, are likely to become more natural and sustainable. Even though fully covered earth-sheltered structures are difficult to integrated with the intense urban fabric, the green roof industry can take advantage of the experience of these types of building types. Green roof system can be revised and new sustainable local systems which are suitable for each region can be developed with the natural systems.