Türkiye'de üretilen hazır cephe elemanlarının iklim kontrolü performansları açısından yörelerde kullanılabilirliğinin değerlendirilmesi

Abstract

Bu tez çalışmasının konusunu, Türkiye'de üretilen hazır cephe elemanlarının pasif ısıtma ve iki imlendirme sistemi öğesi olarak ele alınması ve çeşitli yöreler için bu elemanların iklim kontrolü açısından performanslarının değerlendirilmesi (optimum performansı gösterip göstermediği) oluşturmaktadır. Cephe elemanının optik ve termofiziksel özelliklerinin tümü dış iklim koşullarının etkisi altında bulunan dış kabuktan geçen ısı miktarını doğrudan etkilemektedirler. Bu nedenle iklim kontrolünü sağlamada optimum performans gösteren cephe elemanını tanımlayan optik ve termofiziksel özelliklerin belirlenmesi gerekmektedir. Hazır cephe elemanlarının iklim kontrolü performansları ger çek atmosfer koşullarına göre belirlenen kriter setleri (elemanın yönlendiril iş durumu, eğimi, optik ve termofiziksel özellikleri gibi dizayn değişkenleri) ile kapalı atmosfer koşullarına, bir başka deyişle Bayındırlık ve îskân Bakanlığı'nın Isı Korunumu Yönetmeliği 'ne göre belirlenen kriter setlerine (iklim bölgelerine göre belirlenen pencere-dış duvar ağırlıklı ortalama toplam ısı. geçirme katsayısı, saydamlık oranı, opak bileşenin toplam ısı geçirme katsayısı ve say dam bileşenin toplam ısı geçirme katsayısı gibi dizayn değişkenleri ne) dayanılarak değerlendirilebilirler. Yukarıda değinilen kriter setleri optimal performans gösteren cephe elemanını tanımlamaktadırlar. Ancak dizayn değişkenlerinden yalnız opak elemanın toplam ısı geçirme katsayısına ait değerler üretici firmalarca verildikleri için, bu dizayn değişkeninden hareketle hazır cephe elemanının optimum performans göstermesini sağlayacak saydamlık oranı değerleri önerilmişlerdir. Sonuç olarak; Türkiye gibi güneşli bir ülke sözkonusu olduğun da, optimum performans gösterecek yapı kabuğu termofiziksel özelliklerinin, güneş ışınımının ısıtıcı etkisini de hesaba katan gerçek atmosfer koşullarına göre belirlenmesinin daha doğru bir yaklaşım ola cağı vurgulanabilir.

The subject of this thesis is to evaluate the prefabricated external wall elements that are produced in Turkey, from the stand point of climate control performances. This thesis consists of five chapters: Chapter 1 In the first chapter, the importance of the climatic comfort conditions that must be created in buildings and the convenience of the prefabricated systems are discussed. One of the primary functions of a building is to provide the climatic comfort conditions. Provision of the climatic comfort con ditions in certain periods of the year can be achieved through mechanical heating and climatisation systems that are being actived by various energy resources. In order to prevent excess heat loss and heat gain, buildings should be designed as passive heating and climatisation systems. As the most important component of the passive heating and climatisation systems, external walls have to be mentioned. By using the prefabricated elements, buildings may be con structed in a shorter period of time when compared with other con struction systems. For this reason, prefabricated facade elements produced in Turkey should be evaluated from the standpoint of climate control for various climatic regions of our country. Chapter 2 The definition of the prefabricated elements and various types of the prefabricated facade elements that are produced by different companies in Turkey, are given in this chapter. The prefabricated facade elements which are taken into con sideration in this study are produced by the following companies;. Ministry of Public Works,. Eston, - vi - . Kutlutaş,. Mesa,. Tepe and. Ytong. Chapter 3 In this chapter, the performance requirements that must be met by the prefabricated external wall elements are given. Because of the subject of this thesis, only the provision of the climate control which is one of the performance requirements is taken into consideration.. CI imate Control : The buildings must create an indoor climate, which satisfies the climatic comfort sensation of the users. While using mechanical and climatisation systems to create the climatic comfort conditions, the factors;. insufficiency of the energy resources that are being used in mechanical heating and climatisation systems and the rising prices of them,. air pollution created due to the continious consumption of fuel and extra cost in preventing air pollution must be kept in mind. Because of these factors, mechanical heating and climatisation systems must be used at the minimum level and passive heating and climatisation systems must be used primarily in order to create the desired climatic conditions in a building. Chapter 4 The evaluation of the performances of the prefabricated exter nal wall elements from the standpoint of climate control, are discussed in this chapter. A. Inputs of the Evaluation Process Inputs of the evaluation process may be defined as follows: a. Climatic Conditions: The outdoor climatic elements are; - solar radiation, - outdoor air temperature, - outdoor air humidity and - outdoor air movement. The quantitative values of these climatic elements that are vn - effective on the prefabricated external wall elements cause different indoor climatic conditions. Solar radiation and outdoor air temperature (dry bulb tempera ture) are two important factors in determination of the climate con trol performances, because of their heating effects. Therefore, these two factors must be taken into consideration together. Air humidity is mostly defined as relative humidity. The ef fect of this factor on the indoor bioclimatic comfort situations appears by transferring humidity from outdoor air through the prefab ricated external wall elements. b. Climatic Comfort Conditions: The indoor climatic elements are; - indoor air temperature, - mean radiant temperature, - indoor air humidity and - indoor air movement. The optimum combinations of the values of these climatic com ponents will supply; - the best health conditions for the users, - the maximized performance levels of the users, - pleasent climatic environment for the users. The values of the indoor climatic components must be hold in certain values in order to ensure the climatic comfort conditions. These values may be found from the bioclimatic comfort chart. c. Physical Properties of the External Wall Elements; Optical, Thermophysical and Humidity Transfer Properties: These physical properties are effective on the heat flow rate from the external walls. Optical properties of an external wall element are; - absorbtivity, - transmissivity. ı Thermophysical properties of an external wall element are; - overall heat transfer coefficient, - transparency ratio, --time lag and - decrement factor. Humidity transfer must be taken into consideration because of condensation occuring in external walls. But in this study, climate control will be mainly evaluated from the heat control point of view and for this reason condensation control will not be evaluated. - vm B. Evaluation Criterias The design variables of the prefabricated external wall ele ments from the standpoint of climate control are; - orientation of the facade element, - overall heat transfer coefficient of the opaque component, - transparency ratio of the facade element, - overall heat transfer coefficient of the transparent component, - optical characteristics of the opaque component (colour-absorbtivity). - optical characteristics of the transparent component, and - inclination of the facade element. The values of these design variables make possible to obtain the optimum performances from the prefabricated external wall elements and can be used as the criteria sets in the evaluation process. Criteria sets may be determined by basing on the outdoor and the indoor design conditions: - The outdoor design conditions are derived from the sol -air tempera tures; average daily and hourly sol-air temperatures. - The indoor design conditions are derived from the bioclimatic comfort chart as the dry bulb air temperature, mean radiant temperature and the indoor air humidity. The characteristic period of the year in which the calculations will be done for the selected region is another factor in determining the criteria sets. C. Evaluation Process The climate control performances of the facade elements are evaluated by the criteria sets mentioned above. The evaluation process consists of three steps: a. Determination of the Criteria Sets: The procedure of determining the criteria sets consists of the steps given below: - Selection of the period and the characteristic day for the calcula tions of the values of the design variables. - Determination of the shading effects of the environmental obstruc tions. - Determination of the outdoor design conditions for the calculations of the design variable values for the characteristic day. - Determination of the indoor design conditions. - Determination of the required inner surface temperatures for the opaque component. - Determination of the optimum values of the overall heat transfer coefficient for the opaque component. - Presentations of the evaluation criterias in the graphical formats. IX b. Determination of the Values of the Design Variables of the Prefab ricated Facade Elements from the Standpoint of Climate Control: In this step; - the orientation of the prefabricated facade element, - the overall heat transfer coefficient of the opaque component of the prefabricated facade element, - transparency ratio of the prefabricated facade element, - optical properties of the opaque component, - optical properties of the transparent component, - the inclination of the prefabricated facade element have to be determined. In ideal conditions, the catalogues of the producers must contain all the values of the variables given above. c. Comparison of the Values of Design Variables of the Prefabricated Facade Elements with the Criteria Sets: By comparing the values of the design variables of the prefab ricated facade elements that are effective in climate control, with the optimal combinations (criteria sets), climate control performances of the prefabricated facade elements may be evaluated. Comparison may be done by using the conformable graphics which contain the criteria sets. Chapter 5 In this chapter, the evaluation of the climate control perform ances of the prefabricated facade elements are given. A. Choosing the Criteria Sets that are Used in the Evaluation The criteria sets may be determined for the actual atmospheric conditions and overcast atmospheric conditions. a. The Criteria Sets for the Actual Atmospheric Conditions: The graphics containing all the criteria sets for the actual atmospheric conditions are used in the evaluation process. The assumptions and data used in the evaluation process are summarized as follows: - The calculations are made for the underheated (heating) period for the cities; Ankara, Erzurum, Istanbul and Antalya. The character-, i stic day of this period is; January 21. - In underheated period, for all cities; Ankara, Erzurum, Istanbul and Antalya, facade elements are assumed in sunlight. - The calculations will be done for various orientations and trans parency ratios for 22.5° and 0.05 (%5) intervals, respectively. - It is assumed that external surfaces of the opaque components are painted in dark coloures. The absorbtivity of the dark coloured surfaces is equal to 0.70. - x - - The following window types are assumed to be used:. Wooden sashed; Single glazed windows, Double glazed single sash, Double sash on daufrle frame. Metal sashed; Single glazed windows, Double glazed single sash. In conclusion, the overall heat transfer coefficients of the prefabricated facade elements are calculated in order to obtain the desired inner surface temperatures of the opaque components for the. five different transparent components,. dark coloured external surfaces of the opaque components,. various transparency ratios and. various orientations. In order to obtain a precise interpolation, using the graphics containing all the criteria sets, new graphics were drawen. Each new graphic contains the overall heat transfer coefficients and the transparency ratios for a single orientation and window type. b. The Criteria Sets for the Overcast Atmospheric Conditions: These- criteria sets are determined from the Energy Conservation Regulations of Ministry of Public Works. The Energy Conservation Regulations presents "weighted average of window-external wall overall heat transfer coefficients". According to these regulations, the calculations of the overall heat transfer coefficients do not depend on the orientations, coloures and the inclinations of the facade elements. For this reason, the calcula tions would ensure the best results for the parts of the facade ele ments in the shade. The criteria sets for the overcast atmospheric conditions include; - the overall heat transfer coefficients of the opaque components, - the transparency ratios, - the weighted average of window- external wall overall heat transfer coefficients and - the overall heat transfer coefficients of the transparent components. B. Determination of the Values of the Design Variables Effective on the Climate Control for the Prefabricated Facade Elements The catalogues of the producers do not contain all the design variables. Only, the overall heat transfer coefficients of the opaque components could be found in that step. C. Comparison of the Design Variables of the Prefabricated Facade Ele ments with the Criteria Sets and Suggestions Related with the Application and Use of These Elements. - xi «. a. Comparison and Suggestions for the Actual Atmospheric Conditions: As only the overall heat transfer coefficients of the opaque components have given, a comparison between the criteria sets and the combinations of the design variables couldn't be done. Therefore, only the criteria sets containing the overall heat transfer coeffi cients could be determined. Using these criteria sets, some sugges tions may be determined for - the orientation, - the window type, - the transparency ratio and - the colour of the opaque component for each prefabricated facade element in order to obtain the optimal performance from the standpoint of climate control.. Comparison and Suggestions for the Overcast Atmospheric Conditions: The values of the transparency ratios of the prefabricated facade elements are calculated by using the values of the overall heat transfer coefficients of the opaque components, the weighted average of window-external wall overall heat transfer coefficient and the overall heat transfer coefficient of the transparent components. In conclusion, the results of this thesis are as follows: - The thermophysical properties of a facade element have to be deter mined for the actual atmospheric conditions where the effect of solar radiation on building surfaces is significant, just like Turkey. If the thermophysical properties of a facade element haven't been determined for the actual conditions, the heat insulation pre dicted by neglecting solar radiation will be stronger than actually needed and it will resist solar heat gain through the envelope which is required for heating period. - By the results of the calculations for the actual atmospheric condi tions, the optimum combinations of the overall heat transfer coeffi cients of the opaque components with the transparency ratios were determined for the prefabricated external wall elements according to the cities, orientations and the types of the transparent compo nents. - From the results of the calculations it is understandable that the sufficient technical information haven't been used by the producers.