Thermal performance evaluation of window with transparent insulation slats

Glass facades are widely used by architects due to their good aesthetics, super visual comfort, and good acoustics, but this structure may result in huge energy consumption. In this paper, a novel window with transparent insulation slats (WTIS) using polymethyl methacrylate (PMMA) was studied. An optical and thermal model of WTIS was established and the validity of the model was verified by using experimental data. The instantaneous heat flux, dynamic solar heat gain coefficient (SHGC) and dynamic overall heat transfer coefficient (k-value) were used to evaluate the comprehensive thermal performance of WTIS in comparison to that of normal double glazing (NDG). Besides, the effects of slat spacing and the transmittance of slat on the thermal performance of WTIS were analyzed. The results show that during the cooling season, the peak instantaneous heat flux entering the room through WTIS decreases by 32.7% compared with that through NDG. The average SHGC and average k -value of WTIS are about 20.6% and 17.37% lower than those of NDG, respectively. The total heat gain of WTIS is 35.03% lower than that of NDG in Beijing, while the figure for Changsha is 20.91%. The slat spacing and the transmittance of slat have a positive correlation with SHGC and k-value. This research facilitates the modeling and the application of WTIS.