Search

• A PV assisted ground source heat pump and air source heat pump (PVGSHP-ASHP) system was proposed. • Performance for three GSHP systems were simulated and compared in depth. • Economic optimization of the integrated operation of the PVGSHP-ASHP system was carried out. • The proposed system can solve the load imbalance problem in hot summer and cold winter zones while improving the COP of GSHP and reducing the system cost. The ground source heat pump (GSHP) system is widely recognized as an efficient, clean and economical renewable energy technology for buildings, and can be utilized for building cooling, heating and hot water supply. In the hot summer and cold winter zones of China, however, the total thermal load (heating load and hot water load) of GSHP systems is greater than the cooling load, which may cause a significant soil temperature drop and GSHP performance deterioration. To solve the above problems, a photovoltaic (PV) assisted GSHP and air source heat pump system (PVGSHP-ASHP) was proposed. This paper investigated the performance and feasibility of the PVGSHP-ASHP system, using a case campus building in Changsha city, China. The PVGSHP-ASHP system was firstly established by TRNSYS, and then, its operational performance was evaluated and compared with the PV assisted GSHP (PVGSHP) system and the PV assisted GSHP and electric heater (PVGSHP-EH) system. Finally, the economic optimization of the integrated operation of the PVGSHP-ASHP system was carried out with the combined simulation of TRNSYS and GenOpt. The results showed that for the PVGSHP system, the soil temperature reduced from 18.1 °C to 11.8 °C after 15 years of operation, which caused a decrease in the annual coefficient of performance of the GSHP (COP GSHP) and an increase in the annual electricity consumption. Although the PVGSHP-EH system can solve the load imbalance problem, its annual lifecycle cost (ALCC) increased by 39.3 % due to the low efficiency of the EH. The PVGSHP-ASHP system can solve the appeal problem with high annual COP GSHP and COP sys values of 3.49 kW/kW and 4.69 kW/kW, respectively, and only 71,700 kWh of the annual electricity consumption, while its ALCC was the lowest at 99,223 CNY, which was 8.1 % lower than the PVGSHP system. After optimization, the ALCC of the PVGSHP-ASHP system reached the minimized value of 91,158 CNY, with a reduction of 8.1 %. These findings can provide new ways to solve the load mismatch problem of GSHP systems while enhancing the system efficiency in the hot summer and cold winter zones of China. [ABSTRACT FROM AUTHOR]