Thermal performance and energy flow analysis of a PV/T coupled ground source heat pump system

Ground source heat pump (GSHP) system in cold regions will lead to a decrease in soil source temperature over the years after a long period of operation, and if no timely measures are taken, the system performance will get worse and worse, and even face the risk of shut down. The PV/T (photovoltaic/thermal) is an integrated energy supply system that can both improve the efficiency of solar energy utilization and weaken the soil temperature imbalance. In this paper, the thermal performance and year-round energy flow of the system are analyzed by the simulation model, and the effects of different soil thermal storage control strategies on the thermal storage performance in the transition season are explored. The results show that the coefficient of performance of the heat pump unit can reach 3.99 and 3.96 in the heating and cooling periods. The soil temperature only increases by 0.09 degree celsius and 0.11 degree celsius compared with the initial temperature after five and ten years of long-term system operation, respectively. In addition, after a comprehensive comparison of the thermal storage performance of different control strategies in the transition season, this study found that the temperature difference control strategy was superior to the time control strategy. Ultimately, the annual energy supply of the simulation system produces an additional 391.8 kWh of electricity in addition to meeting the energy demand for cooling, heating and power supply of the building, which realizes the zero-energy operation of the building.