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.