Evaluation of Dynamic Heat Gain of Double Skin Facade Using Response Factor

Recently, the government has been reinforcing thermal insulation requirements for the purpose of reducing energy consumption of buildings. However, enhancing the thermal insulation performance of window glazing of office buildings reduce heating load in winter, but increases the cooling load in summer as well. A countermeasure that can effectively reduce both cooling and heating load of an office building is double-skin façade, an outer openable window system with sunshades installed in the hollow layer. However, when calculating the capacity of air conditioning equipments and its load of an office building with double-skin façade, the load calculation methodology that considers the conditions of both opened and closed outer window is still insufficient. In Korea, u-value of the window at closed state is only considered when calculating the capacity of air conditioning equipments of a building with double-skin facade. Therefore, it is aimed to develop a methodology to calculate dynamic heat gain of double-skin considering operating conditions in summer. Correlation between the amount of global vertical solar radiation in air cavity and the achieved heat gain through double-skin has been presented through a response factor. Transfer function method has been employed in order to calculate the response factor, and the value has been determined through matrix transformation of the transfer function. Experimental values of global solar radiation and temperature have been applied for the analysis of transfer function coefficient using least-squares method. The response factor calculated through experiments can be utilized for estimating the maximum cooling capacity of air conditioning equipments and dynamic heat gain of a double-skin facade