Study on direct solar gain system in houses considering spectral properties of solar radiation

Direct solar gain system to get solar heat directly from the windows is often adopted in houses. On the other hand, if the amount of solar heat gain and thermal mass is not proportionate, this system will not work well. We proposed the blind which reflects near-infrared range upward and transmits visible light. It can distribute acquired solar heat to indoor thermal mass adequately. We evaluated the direct gain system using this blind by experiment and simulation. It is confirmed that the system could improve indoor thermal environment and contribute to energy saving.