Influence of solar-air-source heat pump combination methods on performance of composite heating systems under different climatic characteristics

To explore the influence of different combination methods of solar-air-source heat pumps on composite heating systems, this paper simulates and calculates the operating energy consumption of three heating systems, namely air-source heat pump (ASHP), parallel-connected solar-air-source heat pump (PC-SAHP), and dual-source solar-air-source heat pump (DS-SAHP) during the heating season in six representative cities. The energy-saving and economic performance of the three systems under different climate characteristics are compared and analysed, and the influence law of the collector area on the energy-saving and economic performance of the DS-SAHP system is explored. The results show that the DS-SAHP system can improve the heat collection efficiency and solar energy utilization rate, thereby increasing the annual average COP of the system. Compared with the ASHP system, its maximum increase rate is up to 36.5%. Except for Jinan, the DS-SAHP system has the lowest life cycle cost in different regions, with a maximum reduction rate of 11.5%. The annual average COP of the DS-SAHP system in different regions increases with the increase of collector area, while the life cycle cost of the system shows different laws with the increase of collector area. The energy-saving and economic performance of the system should be weighed and judged according to actual needs to determine the optimal collector area.