Investigation of energy performance of double skin facade in hot-humid climate

Abstract

In buildings, which have a significant share of energy consumption, the proper construction and design of the building envelope is an important issue on all countries due to environmental problems and energy supply. Therefore, controlling the heat loss/gain from the building envelope is an inevitable necessity when considering the increasing building stock in Turkey. Reducing the amount of energy consumed in both new and existing buildings leads to new environmental and climate-sensitive approaches. Double skin facade applications because of the impact on building energy performance is becoming increasingly important. The main purpose of this study is to investigate the effect of the use of double skin facade on the building energy performance through experimentation and simulation in hot-humid climatic regions, especially where the cooling load is high. In double skin facades, the layers consist of transparent surfaces (glasses). Therefore, it is important to examine how to consider to energy loads in terms of glass type selection on double skin facades especially in the hot-humid climatic regions. The study is based on the effect of cooling load on the total heat transfer coefficient (U-value) and the solar heat gain coefficient (SHGC) values from the thermophysical properties of glasses which is one of the main elements of double skin facade systems. As an experimental investigation, a double skin facade was applied at 1/1 scale to the south orientation of an existing education building. The thermal behaviours in the current situation were investigated through measurement data obtained by the reference and experiment office, and the effects on the energy performance of the double skin facade for cooling were calculated. The results show that double skin facade, especially outer layer glass type properties of the facade, is a significant contributor to reducing the cooling load. It has been found that the glass having low SHGC value should be selected for outer layer, and both U-value and SHGC value should be low for the glass of inner layer of the facade. With the use of outer glass having a low SHGC value, it was estimated that the cooling load can be saved between 7.1% and 30.4%. However, if the inner glass type does not meet the above mentioned criteria, the cooling load may increase further. As a result of the simulations, if the U-value of the inner glass and the SHGC value are low, the cooling load will be saved between 4.1% and 13.6%.

Bu araştırmanın asıl amacı, İzmir’de bulunan bir üniversite binasında uygulanan çift kabuk cam cephenin bina enerji performansına etkisini incelemektir. Ayrıca sıcak-nemli iklim bölgesinde farklı termofiziksel özelliklere (U-değeri ve SHGC) sahip cam türlerinin çift kabuk cephe soğutma yüküne etkisi detaylı şekilde incelenmiştir. Alan çalışması olarak, İzmir’de bulunan bir üniversite binasındaki öğretim elemanlarının kullandığı güneye yönelik 2 ofis mekanı seçilmiştir. Aynı özelliklere sahip farklı katlarda yer alan bu ofislerden birine gerçek ölçülerde çift kabuk cephe uygulanmıştır. Böylece belirtilen mekanlarda yerinde toplanan veriler ile deneysel ve sayısal analizler gerçekleştirilmiştir. Tek ve çift kabuk cephe kuruluşuna sahip ofislerin ısıl davranışları, ölçüm sonuçları ile değerlendirilmiştir. Ayrıca farklı cam tiplerine dayalı 6 senaryo oluşturularak simülasyonlar ile soğutma amaçlı enerji performansları araştırılmıştır. Elde edilen bulgulardan genel olarak sıcak-nemli iklim bölgesinde çift kabuk cephe kuruluşu uygulamaları ile soğutma yükünü azaltmak istendiğinde cam seçiminin çok önemli olduğu sonucuna varılmıştır.