İstanbul Yöresi İçin Isıtma Enerjisi Korunumu Açısından Uygun Bina Kabuğu Alternatiflerinin İç Yüzey Sıcaklığına Bağlı Olarak Belirlenmesi

Abstract

Bu çalışmada, ele alınan hacim için ısıtma enerjisi korunumu açısından uygun bina kabuğu alternatiflerinin iç yüzey sıcaklığına bağlı olarak belirlenmesinde kullanılabilecek bir yaklaşım geliştirilmiştir. Yapma çevre hacim düzeyinde ele alındığında, iklimsel konforu etkileyen en önemli iç iklim elemanlarının, iç hava sıcaklığı ve iç yüzey sıcaklığı olduğu söylenebilir. Hacimdeki iç hava sıcaklığı konfor değerinde olsa bile, bina kabuğundaki iç yüzey sıcaklığının istenen değerde olmaması hacimde konforsuzluk durumuna neden olabilir. Bina kabuğu, dış çevredeki iklimsel koşulların etkilerini kontrol altına alarak, hacim içerisinde dış çevreden farklı iklimsel koşulların oluşturulmasında rol oynamaktadır. Bina kabuğundan geçen ısı miktarı, hacmin iç yüzey sıcaklıklarının ve dolayısıyla da iç hava sıcaklığının değişimine neden olmaktadır. Buna bağlı olarak, geliştirilen yaklaşımda kullanılmak üzere, ısı geçişi hesaplarının yapılabilmesi için dış iklim koşullarına ait veriler ve iç yüzey sıcaklıklarının hesaplanabilmesi için de yapma çevreye ait dizayn değişkenlerinin değerlerinin belirlenmesi gerekmektedir. Bütün bu hesaplamaların yapılabilmesi için zamana bağlı ve tek boyutlu ısı geçişi denklemlerin çözümünde sonlu farklar yöntemi kullanılmıştır. Bu yaklaşım ile, yapma çevre değişkenlerinin tasarımı aşamasında, ısıtma enerjisi korunumunda iç yüzey sıcaklıklarına bağlı olarak, en uygun kabuk alternatiflerinin belirlenmesi mümkün olacaktır.

The aim of this study is the determination of the appropriate building envelope alternatives based on the inner surface temperature from the heating energy conservation viewpoint for Istanbul region. One of the most important requirements in a building environment for health is to provide users' bio-climatic comfort. To create an indoor climate which satisfies users' comfort while using supplementary heating in the most economical manner, the architect should pay attention to the determination of the optimum combination of design parameters affecting the indoor climate. Considering a room as the built environment, the most important parameter affecting indoor climate is the building envelope which separates the indoor environment from the outdoor environment and in this way, modifies or prevents the direct effect of climatic variables. Climatic comfort conditions in a room is not only dependent on the air temperature, but also inner surface temperature. Even if, the indoor air temperature is kept at a constant value by means of heating or cooling equipment, due to the thermophysical properties of the building envelope and driving forces of the outdoor climatic elements, inner surface temperature of the envelope varies with the rate of heat flow its components. In order to satisfy the thermal comfort in a room, while using supplementary heating energy in the most economic manner, the building envelope should be designed such that due to its inner surface temperature and the values of other design parameters. Therefore, in this study in order to determine the appropriate building envelope alternatives, a method based on the inner surface temperatures, has been developed. The comfort values of the inner surface temperatures can be estimated by using the relationship between mean radiant temperature representing the surface temperature in a room and the comfort value of indoor air temperature ( ti ). The comfort range for mean radiant temperature in relation to the comfort value of indoor air temperature, such that the difference between mean radiant temperature and indoor air temperature should not exceed the permissible limit value ( s ). In this study the permissible limit value for mean radiant temperature has been considered as its required value and thermal performance of the building envelope has been predicted by evaluating the calculated mean radiant temperature in terms of this required value. In this study, the daily variation of inner surface temperature of the opaque components and one-dimensional temperature distribution within these components have been calculated by using the finite difference method. This study consists of eight chapters. Chapter 1 In the first chapter, the importance of the building envelope and consequently the necessity for the energy conservation are emphasised. Chapter 2 In this chapter, reasons of heating energy conservation requirements are discussed and the factors affecting climatic comfort conditions in a room are introduced. Climatic comfort conditions are defined as conditions which increase users' performance. The architect should pay attention to realise the most convenient environment for the biological, psychological, social and cultural needs for users. Reasons for the decreasing of using energy sources are as follows,. Increasing in the consumption of energy sources used for heating and climatic comfort, speedy and so increasing of their cost.. Increasing of the pollution (air pollution and others) which energy sources used are producted.. Precautions for resisting of pollution are so expensive and. Production cost of electric energy reached so important amount Therefore, energy consumption in buildings should be minimised. Chapter 3 In this chapter, building envelope and inner surface temperature are defined and introduced. Building envelope is defined as the component which separates indoor and outdoor environment. And its functions for basic biological users' requirements are:. To provide climatic comfort in space by controlling the effects of outdoor climatic conditions.. To provide visual comfort dependent on outdoor natural light sources.. To provide auditory comfort by controlling of noise producted by outdoor sound sources. Building envelope can be defined by means of thermophysical and optical properties. Optical properties of the building envelope are,. Absorptivity (a),. Transmissivity (x), ( is not valid for opaque components ). Reflectivity (r), XI Thennophysical properties of the building envelope are,. Overall heat transfer coefficient (k),. Transparency ratio (x),. Time lag. Decrement factor Chapter 4 The relationships among heating energy conservation, building envelope and inner surface temperature are discussed in this chapter. In order to reduce mechanical heating cost, room should be designed as optimal passive heating system and heating period should also be evaluated with respect to energy conservation. Chapter 5 This chapter sets principles and the steps of a new method which can be use for determining appropriate building envelope alternatives related to heating energy conservation and dependent on inner surface temperature. Methods for calculating the amount of heat transfer depending on the heat storage capacity of the outdoor wall and heat flow variability according to the time are also explained. The main steps of the new method are as follows:. Determination Of The Characteristic Design Days For the calculations used in the approach, it is necessary to take into consideration; both the outdoor climatic data according to the design day of the year and the indoor climatic data such as the indoor air temperature. Determination of the values of design variables This step includes; the determination of the using period of the space, the location of the building according to the other building, dimensions of the space, the absorptivity of the building envelope, the transparency ratio, the value of the required overall heat transfer coefficient of opaque component with respect to the orientation and the transparency ratio and the detail of opaque component which satisfied the required overall heat transfer coefficient. The limit value of the overall heat transfer coefficient can be determined by means of several graphics, obtained from some researches. Steps are,. Determination of outdoor design conditions. Determination of indoor design conditions. Determination of other outdoor components effected climatic comfort and envelope design. Calculation of sol-air temperature effected envelope components. Calculation of sol-air temperature effected opaque components. Calculation of sol-air temperature effected transparent components. Determination of overall heat transfer coefficient of opaque component. Determination of opaque component alternatives by basing on the optimum values combination of thennophysical properties xn . Calculation of the hourly values of the inner surface temperature of opaque component alternatives. Calculation of requirement inner surface temperature for opaque and transparent components. Determination of appropriate envelope alternatives by comparing inner surface temperature calculated and requirement inner surface temperature Chapter 6 This chapter consists of the application of the method to the Istanbul region. Chapter 7 This chapter covers the results of the application study. As the results of the application some graphic systems are prepared. These graphic systems include the analysis of the different opaque component alternatives related to different insulation materials which provide the required inner surface temperature from climatic comfort and heating energy conservation viewpoint. When graphics are compared, those results are provided: 1. Extruse poly strene hard foam 2. Glass wool 3. Shaving of wood board 4. Gas concrete insulation plate 5. Heraklith are the most appropriate heating insulation materials, in order. Among main materials, 1. Gas concrete block 2. Horizontal holed brick wall 3. Reinforced concrete wall are the most appropriate main materials, in order. When results are considered, we can said that, 5 numbered building envelope alternative which consists extruse polystrene hard foam and gas concrete is the most appropriate alternative for this study. Chapter 8 The main purpose of this study is to introduce the new method which is developed to be used for determination of the appropriate building envelope alternatives based on the inner surface temperature from the heating energy conservation viewpoint. The application of the method for Istanbul region was given as an example. The results of the computations can be expressed graphically ( Figure 6.3-6.17 and Figure 6.18 - 6.22 ). And results are explained as, xm a Innovations of this study for scientific viewpoint: a how benefited from this study in practice By means of the method in the design process, it is possible to determine the most appropriate building envelope alternative among different alternatives with regard to heating energy conservation. At the same time, this method can be used for the evaluation of the different insulation and opaque component materials in practise.