Thermal behavior of double glass window filled with absorbing and non-absorbing gas

摘要

This paper presents a radiant model based on the radiant resistance analysis theory and the results of numerical simulations of double glass window. The two-dimensional steady state model is formulated based upon the radiation and free convection heat transfer at different external and internal ambient conditions.The properties of glass which change with incident wavelength are also considered. Specifically, air and CO_2 are used as the medium in the 8mm and 1 Omm cavity of the double glass window, respectively. Several parameters, including transmitted solar radiation flux, temperature distribution, surface heat transfer coefficient for free convection and total surface heat flux are calculated. The results show that transmitted solar radiation flux is slightly lower when filled with CO_2 in the cavity than with air due to their absorption difference. Also, the temperature of gas closing to internal glass sheet and the total surface heat flux of internal glass sheet are decreased when filled with CO_2 than with air, although the surface heat transfer coefficient is slightly higher when it is CO_2 The temperature variation curves show that less heat flows into the room when filled with CO_2 than air in double glass window.