İklimsel karaktere bağlı olarak optimum performans gösteren yerleşme yoğunluğunun belirlenmesinde geliştirilen bir yöntem

Abstract

ÖZET Bu çalışmada, yerleşme yoğunluğunun şimdiye değin, tasarcının öznel yargılarıyla ve öznel ölçütleriyle ortaya konmuş olma sı, nesnel ölçüt olabilecek iklimsel gereksinmelerin bu alanda hesaba katılamamış olması, konunun seçiminde birer ge rekçe oluşturmaktadır. Bu konu çerçevesinde çalışmanın amacı, yoğunluğun, bir yer leşmenin kapladığı alanın büyüklüğünün belirlenmesinden baş layarak, insanın çeşitli eylem alanlarındaki uygun çevresel koşulların -iklimsel karakterlere bağlı olarak- yaratılma sında kullanılabilecek nesnel bir ölçüt olarak yerleşme ta sarlama sürecine katılmasına olanak veren yeni bir yöntem geliştirilmesidir. Çalışma beş ana bölümden oluşmaktadır. 1. Bölüm: İlk bölümde, öncelikle yerleşme yoğunluğunun iklimsel karak tere bağlı olarak belirlenmesi sürecinde, girdilerin seçimi ve ne gibi değişkenlere bağımlılık gösterebileceklerinin belirlenmesi yer almaktadır. Böylece bu bölümün sonunda, yerleşme yoğunluğu belirlenme sinde iklimsel etken olarak ele alman güneş ışınımı ve rüz garın değişimine neden olan geometrik ve fiziksel koşullar la, yapma çevreye ilişkin ne gibi değişkenlerin ele alınma sı gerekliliği ortaya çıkmış, iklimsel karakter olarak ülke miz için geliştirilecek çalışmada yararlanılacak kaynaklar belirlenmiş olmaktadır. 2. Bölüm: İkinci bölümde tezin amacına uygun olarak, yerleşme yoğun luğunun, iklimsel gereksinmeler açısından performans istek lerinin, bu istekler ve yerleşme yoğunluğu arasındaki iliş kilerin ele alınış biçimi açıklanmaktadır.- vı - 3. Bö lüm : Üçüncü bölümde, yerleşme yoğunluğu belirlenmesinde doğrudan olmasada dolaylı olarak iklimsel verileri ele alan önceki çalışmalar, kapsamları ve davranış biçimlerine göre sınıf landırılarak tanıtılmakta ve değerlendirilmektedirler. 4. Bölüm: Bu bölümde, iklimsel performans açısından yerleşme yoğunlu ğunun belirlenmesinde geliştirilen yeni yöntem tanıtılmak tadır. Yöntemin geliştirilmesinde izlenen süreç, başlıca üç evre den oluşmaktadır. Birinci evrede yerleşme yoğunluğu belirlenmesinde ölçüt oluşturabilecek performans istekleri belirlenmiştir. Ayrıca bu evrede yerleşme dokusu geometrik özelliklerinden biçim, konum, aralık ölçü değişkenleri ve yoğunluk arası ilişkiler ele alınarak, bunlara bağlı yoğunluk almaşıkları üretilmiştir. İzlenen sürecin ikinci evresinde bir performans değerlendir me yöntemi ortaya konmuştur. Bu evre performans istekleri açısından ölçüt belirlenmesi, değerlendirmede kullanılacak benzetimin modelinin geliştirilmesi, uygun çözümlerin orta ya konması adımlarından oluşmuştur. Son olarak geliştirilen bağıntılar yardımıyla, üretilmiş olan yoğunluk almaşıklarının verdiği performans değerleri nicesel olarak ortaya konmuş ve uygun çözüm almaşıklarının seçimi, ele alman örneklerle verilmiştir. 5. Bölüm: Bu bölümde yöntemin ortaya koyduğu sonuçlar, getirilen ye nilikler, uygulanabilirlik ve gelişebilirlik açısından ir delenerek aşağıdaki sonuçlara varılabil inmiştir. Yöntem, yerleşme ölçeğinde iklimsel etkenlerin denetiminde geometrik ve fiziksel olarak çok boyutta değişkenin ele- vıı - alınmasına, bunların değişkenlik sınırlarının genişliği ne deniyle tasarlamacıya esneklik getirilmesine ve birer para metre olarak ele alınan bina biçimi, konumlandırması, bina aralıklarının saptanmalarına hizmet etmektedir. Uygulanabi lirlik açısından, yöntem bilgisayar tekniğinin yaygınlaşma sı oranında geniş uygulanma, çok sayıda örneğin bir arada ele alınma ve böylece yerleşme ölçeğinde tasarlamalarda kullanılmak üzere bir dizi standart elde etmeye yönelik so nuçlar verebilmektedir. Yöntem, kullanılan benzetişim modeli açısından güneş ışını mı konusunda daha geniş esnekliğin getirilmesi ve rüzgar açısından yapılacak deneysel çalışmalara paralel olarak do ğal vantilasyon çalışmalarında da kullanılabilir duruma ge tirilmesi konularında gelişmeye açıktır.

SUMMARY The present study is based on the assumption that the most important stage in the process of designing the built envi ronment on the settlement level is the process of deter mining settlement intensity. Therefore the thesis takes this process as its subject. The reasons behind the selection of the subject may be sum marized as follows: Settlement intensity has hitherto been determined through the subjective judgment and subjective criteria of the designer. Moreover climatic needs which could serve as ob jective criteria have not been taken into account in calcu lations. Within the context of this subject, the aim of the present study may be formulated as follows: The development of a model which enables the usage of den sity as an objective criterion in the process of creating optimum physical environmental conditions (depending on climatic characteristics) in various fields of human activ ity, the determination of the size of the area of a settle ment. The study consists of five main sections. Section 1; The first section is devoted to the determination of the selection of inputs and the factors these inputs may depend upon in the process of determining settlement intensity as dependent upon climatic characteristics. This section treats solar radiation and wind, two of the determinants of climat ic characteristics, mainly in terms of their interactions with the natural and the built environment at various levels, These levels denote the natural and built environment in three scales: the world, macro-scale natural and built environment and the settlement. Solar radiation, depending on these scales, is affected by atmospheric conditions, orbital movements of the world,- ıx - other large or small scale physical conditions and is al tered quantitatively and qualitatively until it reaches the quantity valid in the design of settlements. Wind and air movements, on the other hand, are affected by atmospheric pressure systems, Coriolis forces, frictional resistance, buoyancy forces and viscous forces' on the world level; surface formation, ground roughness, surface covering materials in macro level natural environmental systems; forms, dimensions and surface covering materials of environ mental obstacles. The second stage of the first section treats studies on user needs in terms of climatic conditions and climatic characteristics. In conclusion, this section emphasizes the necessity of considering geometrical and physical conditions, causing changes in solar radiation and wind, which are climatic fac tors, and variables pertaining to the built environment. It also determines the sources which may be of use to a study developed for the climatic characteristics of our country. Section 2: The second section explains the treatment of settlement intensity, performance requirements in terms of climatic needs, and the interrelations of these requirements and settlement intensity, in accordance with the aim of the thesis. It is concluded that in the determination of intensity, it is necessary to take into account the smallest unit which could serve as a model in the solution of problems relating to settlements and to treat coefficients, which could serve as objective criteria together with numerical values depen dent upon performance requirements since individuals occu pying a unit area show variety in certain factors. Thus, interrelationships of performance requirements and intensity are considered within this context.- x - Section 3: The third section introduces previous studies indirectly taking climatic data into account in determining settle ment intensity through a classification according to their coverage and approach and evaluates these studies. These methods and theoretical studies, in terms of the approach adopted follow linear and numerical procedures. Experimental studies, on the other hand, rely on measure ments conducted on models. Finally these methods are evaluated; it is concluded that the development of a new model is necessary and that this model should be a numerical simulation model. Section 4: This section introduces the new method developed for deter mining settlement intensity in terms of climatic perform ance. The aim of the method is: to offer an approach, as flexible as possible. enabling the evaluation of all possible alternatives and to provide support for future research in this area. The assumptions underlying the development of the model may be listed as follows: o Control of solar radiation and wind, enables the control of the effects of other variables, that is, air tempera ture and air humidity. This is rendered possible by developing performance criteria relating to sol-air tem perature symbolizing the joint effects of air temperature and air movement. o Taking buildings, as design variables on the settlement level, form and dimensions are considered as parameters. o An open space unit is considered sufficient as the on the settlement level. o It is necessary to obtain climatic data, which are to serve as inputs for the process to be developed, through calculations.- xı - The process of developing the method consists mainly of 3 phases. In the first phase, the performance requirements which could be taken as criteria in the determination of settlement intensity are defined as follows: Solar radiation on the highest levels of the vertical sur faces of buildings should be maximized during the under- heated period and minimized during the overheated period, these surfaces should take radiation during the period when air movement is necessary and that they should be protected from radiation during the period when air movement is not desired. Moreover this section treats interrelationships of geomet rical characteristics of settlement texture, e.g. form, location, distances and dimensions and creates alternatives for intensity depending upon these variables. The second phase offers a method for performance evaluation. This phase consists of the following steps : the determina tion of criteria in terms of performance requirements, the development of the simulation model to be used in the evalu ation process and the development of appropriate solutions. The criterion determined in terms of solar radiation may be stated as follows: Shaded areas created by buildings on the vertical surfaces of other buildings and the consequent total solar radiation should be known. The development of the calculation method in evaluating solar radiation has been realized in 3 phases. In the first phase, data for solar radiation calculations have been obtained through a method by A.Öztürk-A.Kılıç, which is a calculation process in line with the principles set out above and which is used for determining correla tion coefficients, relying on data for Turkey. The basic principle underlying the second phase is as follows: Simulation of shaded areas on vertical surfaces of buildings created by neighbouring buildings may be rendered possible by the shadow components of a vertical pole on a three-- xıı - dimensional coordinate system. F as the shadow component of a vertical pole on a horizontal surface may be obtained by the following trigonometric equation, F = H/tanga H = length of pole a = sun altitude angle FX, the component in east-west direction may be obtained as follows FX = H sina / tana FY, the component in north-south direction may be obtained as follows FY = H cosa / tana FZ, the height of the shaded area created on a building with height H by another building surface may be calculated by the following equation: FZ = FX ~ BX FX / H or FZ - FY~M FY / H where, BY = the distance between buildings in the north-south direction BX = the distance between buildings in the east-west direc tion Subsequently the widths of the shaded areas on the same surface, GX or GY, may be obtained through special solutions of the following general equations, under various boundary conditions.- xııı - GX = f(l/YA, BX, BY, BDY) GY = f(YA, BY, BX, BDX) where YA = the angle between F and west-east axis BDX= the width of the building creating the shaded area in the east-west direction BDY= the component of the building creating the shaded area in the north-south direction. Thus, shaded area GOLA is obtained through special solutions of the following general equations. GOLA = f(GX, GY, GZ) GOLA = f(YA, BDX, BDY, BDZ, BX, BX, FX, FY) The third phase determines inputs and dimensions related to the settlement for the computer programme. The following calculation process integrating the evaluation of solar radiation and wind effects has also been realized in three phases. The first phase of this stage of development covers the mathematical expression of the shading effects of wind ve locity and solar radiation. Sol-air temperature, affecting building surfaces, TEO may be obtained through the following equation. TE0(1,J)=TD(I) + HST^(JİAÜW HST(I,J)=HB(I,J)+HYY(I,N1)+HYN(I,N1).ALAN(J)-HB(I,J).TGOLA(I,J)/ALAN(J) where HST(I,J) =total solar radiation on the vertical surface of the building HB(I,J) =direct radiation- xiv - HYY(I,Nl)=diffuse radiation HYY(I,Nl)=reflected radiation ALAN(J) =vertical surface area of the building TGOLA(I,J)=total shaded area on the vertical surface of the building. I = index denoting calculation hours J =index denoting directions of building surfaces. Therefore external surface film coefficient ALFD(J) may be obtained by taking into account the wind effects on the surface through the following formula: ALFD = HW(J) + HR where HW(J)= convection coefficient HR =radiation coefficient. Finally, the performance values of the intensity alterna tives created have been expressed numerically through the equations above and the selection appropriate solution alternatives has been demonstrated on various examples. Section 5: This section evaluates the consequences and, the contribu- tions of the method from the standpoints of applicability and development potential and formulates the following conclusions: The method serves the treatment of multi-dimensional geo metrical and physical variables, brings flexibility to the designer through the wide extent of variability and also to the determination of building form, location and dis tances, taken as parameters, in the control of climatic factors on the settlement level. As far as applicability is concerned, the method presents possibilities of wide appli-- xv - cation depending upon the wide use of computer techniques, rendering possible the treatment of many samples at a time and thus creating a series of standards for design on the settlement level. The method may be developed further with the aim of enhancing flexibility in the area of solar radia tion in terms of the simulation model and with the aim of rendering natural ventilation studies feasible parallel to the experimental wind studies.