Thermal equilibrium research of solar seasonal storage system coupling with ground-source heat pump

•Thermal equilibrium for solar seasonal storage system was studied.•The solar heat storage system based on ground-source heat pump.•Solar heat storage experiment was performed.•The solar heat storage process was simulated by TRNSYS 16.

Although GSHPs (ground-source heat pump system) have already drawn a fair amount of attention in China because of its high energy efficiency and low environmental impact characteristics, some practical problems appeared much more than the expected. COP (Coefficient of Performance) of the GSHPs decreased gradually year after year caused by imbalance energy loads especially in heating-dominated climate zones. So an experiment of solar seasonal storage coupling with GSHP was designed and implemented. In this thermal storage experiment process, a system with 1500 m solar thermal collectors and 580 sets of 120 m deep ground thermal exchangers were taken into research. Thermal equilibrium of soil was studied; relationship between solar energy radiation quantity and thermal storage quantity was discussed. Results showed that solar energy utilization efficiency achieved 50.2% and soil temperature raised by 0.21 °C. TRNSYS 16 was used to simulate thermal storage experiment, and simulation results were well matched with the measured data.