Numerical study of a dual-function solar collector integrated with building in water heating mode with natural circulation

As a building integrated solar thermal system, the dual-function solar collector integrated with building works for passive space heating in cold winter season, and for water heating in warm seasons. In this study, a numerical study is made on the dual-function solar collector integrated with building when it works in water heating mode with natural circulation. According to practical building structure and building material, an air-conditioned room is designed. The numerical simulation is achieved to show the influence of thermal insulation of backboard and water volume on the novel system's thermal performance of water heating and thermal effect on the building environment. The results show that the operating water volume within the 40-50 kg/m2 is appropriate in summer, and the appropriate thickness of the thermal insulation of backboard was around 5 cm.