The air-ground hybrid source heat pump system can realize indirect air source heat pump mode and heat compensation mode through an air-water heat exchanger

which could compensate for the difference between heat extraction and heat injection to the soil. This could solve the problem of soil heat imbalance caused by the long-term operation of the ground source heat pump system in northern China. In this study

the residential buildings in five cities of northern China were used as examples and a model of air-ground hybrid source heat pump system was established on the TRNSYS platform. To minimize the number of ground heat exchangers and ensure a good heating effect

the matching design of ground heat exchangers and air-water heat exchangers was explored and the performance and reduced number of ground heat exchangers of the air-ground hybrid source heat pump system were simulated and analyzed. The results showed that the maximum reduction ratios of the ground heat exchangers in Harbin

Changchun

Shenyang

Beijing

and Jinan were 29%–43%

and 0.029–0.050 m2 of air–water heat exchangers were needed per linear meter of ground heat exchangers. The air–ground hybrid source heat pump system with a reduced number of ground heat exchangers could provide a stable soil temperature during a long-term operation. Its total cost saving rates for ten years were 12.6%–25.3%.