A model of the long-wave radiation heat transfer through a glazing

Considering convection heat transfer between inside and outside surfaces of the glazing and conduction heat transfer of glass sheet, this paper presents a mathematical model of the long-wave radiation heat transfer between inside room surfaces and outside environmental surface through a glazing. The effects of three main factors on the overall heat flux are evaluated. Three main factors are the glass transmittance of long-wave radiation, convection heat transfer coefficient of inside and outside glass surface, the difference between the inside room surface temperature and the indoor air temperature as well as the difference between the outside environmental surface temperature and the outdoor air temperature. If the long-wave radiation transmittance approaches to 0.1, the effects of the transparence radiation of glass or some polymer material on the overall heat flux are obvious and cannot be ignored. The effects of convection heat transfer coefficient of inside and outside glass surface on the overall heat flux are relatively weak. If the temperature difference between the surface and air temperature is less than 2 °C, the effects on the overall heat flux and the role of the transparence radiation are weak. But if the difference is large, the effects are obvious and significant.

► Long-wave heat radiation model considering transmittance of glazing is reported.
► Radiation, convection and conduction are considered at the same time in the model.
► Transparence radiation of glazing cannot be ignored when transmittance exceeds 0.1.
► Convection heat transfer coefficient has weak effect on the results.
► Effect of surface and air temperature difference on the results is significant.