Bina içi çevre mekanlarının işlevine ve bina kabuğuna bağlı iklimsel konfor açısından yön seçiminde bir yöntem

Abstract

ÖZET Bu çalışmada, opak kabuk iç yüzeyinde gerçekleşen yüzey sıcaklıkları ile iklimsel konfor açısından olması gerekli iç yüzey sıcaklıkları arasındaki farklara dayalı olarak, mekânların yönlendirilme sini amaçlayan bir yöntem geliştirilmiştir. Yöntemin, işlevi, kabuk bileşenleri, yatay ve düşey bölme elemanları, ölçüsel boyutları, kullanıldığı zaman ve süre, bulunduğu iklim bölgesi bilinen, bir binaya ait herhangi bir mekân için kullanılması sözkonusudur. Bu yöntemde, iklimsel konfor açısından, bina içi çevre hava sıcaklığı ile ortalama ışınımsal sıcaklık arasındaki, kullanıcının hiç bir desteğe gereksinme göstermeden, kendi metabolizmal gücüyle karşılayabileceği limit sıcaklık farkının (±e), bina içi çevre hava sıcak lığı ile bina kabuğu iç yüzey sıcaklığı arasında, mekânın kullanıldığı zaman dilimi içerisinde korunabilmesi esas alınmıştır. Bina kabuğunu saydam ve opak bileşen meydana getirmektedir. Opak bileşeni oluşturmak için çok çeşitli malzeme kullanmak olanaklı olmasına rağmen, saydam bileşeni oluşturan malzemeler aynı seçenek zenginliğine sahip değildir. Diğer taraftan, saydam bileşeni meydana getiren ana malzeme camdır. Binalarda kullanılan pencere camlarının zaman geciktirmesi ihmal edilebilecek seviyededir. Dolayısıyle kabuk dış yüzeyinde oluşan sıcaklıklar sebebiyle, kabuk bünyesinde gerçekleşen ısı geçişini kontrol etmek, opak bileşene düşmektedir. Yöntem, yukarıda belirtilen kabuller çerçevesinde, opak kabuk iç yüzeyinde, yönlere göre gerçekleşen ve istenen iç yüzey sıcaklıkları arasındaki farklara dayalı olarak, sözkonusu mekânın, yönlendirilmesine ilişkin tercih sıralaması belirlemektedir. Buna göre, bina içi çevreyi meydana getiren mekânların, bina dışı çevre ile ilişki kurabilmesi, aynı zaman da birbirleriyle olan ilişkilerinin koordinasyonu olanaklı olmaktadır. Bina dışı çevre etkenlerinin, bina içi çevredeki termal etkilerine dayalı olan bu sıralamanın, diğer yönlendirme yöntemlerinde olduğu gibi, yöredeki rüzgâr etkileri dikkate alınarak düzeltilmesi de, yön temde öngörülmektedir. Opak kabuk iç yüzey sıcaklıkları, mekânda bir ek yapma ısıtma sisteminin görev yaptığı kabul edilerek, sonlu farklar yöntemini kullanan bir bilgisayar programı ile hesaplanmaktadır. Bu yöntemle, bir bina içi çevreyi oluşturan mekânların bina dışı çevre ile olan iliş kilerinin hangi yönlerde kurulması gerektiğine, diğer tasar değişkenlerine ilişkin kriterler önemini kaybetmemek üzere, iklimsel konfor açısından karar vermek olanaklıdır.

SUMMARY A METHOD FOR DETERMINING ORIENTATION BASED ON INDOOR ENVIRONMENTAL FUNCTIONS AND BUILDING ENVELOPE, FROM THE VIEWPOINT OF CLIMATIC COMFORT In this study, a method for determining the orientation of building spaces is developed, based on temperature differences between the actual and the required inner surface temperature of the opaque envelope to provide climatic comfort for users. The subject of in quiry is the orientation of interior spaces of a building. For the accomplishment of this purpose, the function of that space, components of the envelope, both vertical and horizontal partitions, dimensions, the time and length of period of use of that space during the day and throughout the year, and climatic zone should be taken into considera tion. To have climatic comfort within an indoor environment, there should be a limit value (e) for the difference between indoor air temperature and average radiant temperature, When this temperature difference is at a value of e the users are considered to have climatic comfort with the help of their own metabolisms. Average radiant temperature is the mean value of the sum of all inner surface temperatures. If there is a supplementary heating or cooling system within the building, it is possible to consider the surface tempera ture of vertical and horizontal partitions as equal to the indoor air comfort temperature. In such a case, only the inner surface tempera ture of the building envelope can be considered as equal to the indoor air comfort temperature with the help of heating or cooling systems. Yet, there will be heat transfer through the building envelope due to effects caused by outdoor environmental climatic factors, producing an inner surface temperature difference. For climatic comfort, the difference between inner surface temperature and indoor air tempera ture should be at a value of e. A building envelope consists of transparent and opaque components. While there are many possible variations in the material composition of the opaque component, the options in the composition of the trans parent component are limited. The main material used for the trans parent component is glass. Insulation capacity of the window glass in neglectable. Hence, the basic element that controls heat transfer through the building envelope becomes the opaque component due to temperature effects formed at the outer surface of the envelope. As solar radiation effecting the outer surface of the opaque component changes, heat transfer through the opaque component and inner surface temperature also change, when direction is taken into consideration. The method developed in this study proposes a ranking of orienta tion options. These options are based on temperature differencesbetween the actual inner surface temperature of the direction chosen, and the required inner surface temperature. Yet, like all other methods developed for bringing solutions to orientation problems, the method proposed here should also be reconsidered with the wind effect included. Then, it will be possible to decide on the orienta tion of spaces and on the coordination of their interrelationship. The study consists of four chapters. Chapter 1 In this chapter, the significance of the subject is touched upon, and the existence of orientation problems even in prehistoric ages, although solved intuitively by humans, is discussed. Chapter 2 This chapter covers description of factors that are effective in the formation of a space within a building. These factors can be grouped into two as climatic and functional. Climatic factors are defined within the context of climatic comfort. Outdoor climatic factors can be classified as follows:. air temperature. solar radiation. relative air humidity. wind Indoor climatic variables are determined as follows:. air temperature. mean radiant temperature. air humidity. air velocity. The role of the building envelope is to keep the indoor environ mental climatic comfort variables within required limits by con trolling outdoor climatic effects. Indoor environmental climatic comfort conditions are not independent of the function of that space. Activities that take place within a space, dimensions of the space, and the most important, the time and length of period of use of that space during the day and throughout the year will determine when and within what intervals climatic comfort variables should stay. Hence, it will be possible for the building envelope to exhibit the required performance within determined time intervals. Chapter 3 In this chapter, factors effective in the determination of components of a building envelope are explained. - vx -A building envelope consists of an opaque and a transparent component. What controls the outdoor climatic influences is mostly the opaque component. Hence, transferral of thermal influences from the outer surface to the. inner surface of the envelope depends on the thermal radiation capacity of the opaque component. Further, thermal diffusion capacity of the opaque component, is determined both by its heat storage capacity and its insulation resistance. There is no specific method developed for calculating the heat storage capacity of the opaque component with precision. But, there are a number of methods for calculating the insulation resistance of the opaque component. These methods are based on the amount of re quired optimal heat flow through the opaque component. Information concerning these methods are given in this chapter. It is a well known fact that the heat storage capacity of the transparent component is a neglectable quantity. Insulation resist ance is within defined limits depending on the nature of materials it is produced of. In addition, while it is rather easy to calculate the amount of heat flow through the transparent component and its inner surface temperature, we have difficulties in doing the same calculations for the opaque components. This chapter concludes with an explanation of methods for the calculation of the actual inner surface temperature of the opaque component, and methods for the calculation of the required inner surface temperature of the opaque component based on the transparent component's inner surface temperature. Chapter 4 This chapter describes the step of the method proposed in this study in the determination of appropriate directions for spaces, as related to the function of those spaces and the performance of the building envelope. Previous methods pertinent to orientation problems base their calculations on the intensity of solar radiation effecting either the unit area or the total area of the outer building surface. In fact, the performance that the building envelope exhibits under outdoor climatic effects, changes depending on the quality of this envelope. The quantifiability of solar radiation led researchers to consider this variable as a measure in determining the orientation of buildings. But, it is not possible to determine the conditions - vii -for providing indoor comfort, unless the performance of the envelope is not defined. Methods proposed are only applicable either at the building or city scale, and accurate results have not been reached at the space scale. The aim of this method proposed here is to bring a ranking of performance levels that the building envelope alternatives will exhibit under effects of,. solar radiation,. outdoor air temperature, and. wind, depending on the directions chosen and within intervals of time when this space is used. With such a ranking, it well be possible to reach higher levels of performance in climatic comfort, energy con servation and hygenic conditions related to the organization of spaces within a building. The steps to be taken for the accomplishment of this purpose are stated as follows: - Determination of the function and dimensions of the space and the intervals of time when this space is used, - Type of material used for the transparent component and in connection with this, determination of insulation resistance values for the opaque component, - Determination of alternatives for the opaque component, - Calculation of both actual and required inner surface tempera tures for the opaque component under predetermined conditions, and their graphic representation, - Selection of an appropriate direction depending on the dif ferences between the actual and required inner surface temperatures. With this method, - Widening the spectrum of directions determined by the sol-air orientation method and by other relevant methods, - Finding practical solutions, for the flexibilities of the sol- air orientation method, - Comparing alternative indoor solutions from the viewpoint of orientation, - Coordination of spaces within the spectrum of these direc tions. - Comparison of the performance levels of opaque component alternatives with each other with reference to directions, - vnx -- Selection of an envelope combination appropriate for a space whose function is known, - Generation of envelope combinations and direction alternatives for a space whose function is taken as constant but dimensions changing will be attainable. - IX -