열전도 해석을 이용한 공기층의 유효열전도계수 추정

Abstract

Purpose: Recently, with the development and reliability of computational analysis method, thermal conduction analysis have been an important process in an architectural design. Especially, the thermal conduction analysis in the window frame is used instead of the experiment because it saves time and expense. Except for glass, window frames are made of various materials and there are many air cavities inside the window frames. Therefore, in order to accurately estimate the thermal transmittance ( ) of the window frame, a method of appropriately predicting the effective thermal conductivity coefficient of the air cavities is required. In this study, we estimate the effective thermal conductivity coefficients of air cavities. Method: We apply formulas of ISO 10077-2 to our scheme developed in previous study and then estimate the effective thermal conductivity coefficients of air cavities using iterative calculations. Thermal conductivity coefficient of air is used as the initial value of the simulation. Subsequently, the calculated coefficients are used in next simulations. The simulations are conducted until the values does not change. Finally, the obtained thermal conductance and thermal transmittance are compared with the values in ISO 10077-2. Result: We conduct the thermal conduction simulation for ISO 10077-2 D2, and estimate the effective thermal conduction coefficients of air cavities. In addition, the temperature distributions are obtained by using the effective thermal conductivities. From the simulation results, it is confirmed that the effective thermal conductivities of air cavities having a long length in the direction of the heat flow have a large change. In the future work, we will add the process automatically calculating effective thermal conductivity on our code.