Global building energy consumption is significantly increasing. Utilizing renewable energy sources may be an effective approach to achieving low-carbon and energy-efficient buildings. A combined system incorporating solar photovoltaic–thermal (PV/T) components with an air-source heat pump (ASHP) was studied for simultaneous heating and power generation in a real residential building. The back panel of the PV/T component featured a novel polygonal Freon circulation channel design. A prototype of the combined heating and power supply system was constructed and tested in Fuzhou City, China. The results indicate that the average coefficient of performance (COP) of the system is 4.66 when the ASHP operates independently. When the PV/T component is integrated with the ASHP, the average COP increases to 5.37. On sunny days, the daily average thermal output of 32 PV/T components reaches 24 kW, while the daily average electricity generation is 64 kW·h. On cloudy days, the average daily power generation is 15.6 kW·h; however, the residual power stored in the battery from the previous day could be utilized to ensure the energy demand in the system. Compared to conventional photovoltaic (PV) systems, the overall energy utilization efficiency improves from 5.68% to 17.76%. The hot water temperature stored in the tank can reach 46.8 °C, satisfying typical household hot water requirements. In comparison to standard PV modules, the system achieves an average cooling efficiency of 45.02%. The variation rate of the system’s thermal loss coefficient is relatively low at 5.07%. The optimal water tank capacity for the system is determined to be 450 L. This system demonstrates significant potential for providing efficient combined heat and power supply for buildings, offering considerable economic and environmental benefits, thereby serving as a reference for the future development of low-carbon and energy-saving building technologies.

The direct-expansion solar photovoltaic/thermal (PV/T) coupled air-source heat pump (ASHP) system is an integrated technology for the combined domestic hot water and electricity supply of rural buildings, but the variation in its performance across climate zones limits confidence in its large-scale deployment. In this study, a TRNSYS 18 model was established and validated against experimental data, with all mean bias errors (MBE) within ±10%, satisfying ASHRAE Guideline 14-2014. Annual simulations were performed for five representative cities of the building climate zones of China: Harbin (severe cold), Beijing (cold), Shanghai (hot-summer cold-winter), Fuzhou (hot-summer warm-winter), and Kunming (mild). Compared with the standalone ASHP system, the COP of the PV/T-ASHP system increases by 13.94–30.64% when the PV/T evaporator is in operation, with the most pronounced improvement in the severe-cold zone. The annual power generation of the PV/T system is 25.08–33.95% higher than that of the conventional PV system, with an annual mean electrical efficiency of 19.53–21.67%; the annual useful heat production ranges from 78,406.31 MJ (Harbin) to 110,656.16 MJ (Kunming), and the primary energy saving ratio reaches 66.27–74.57%. The system exhibits superior comprehensive energy performance in all climate zones. This study provides technical guidance for climate-specific application and optimal configuration, and proposes improvement measures for cold and severe cold regions.