A ground source heat-pump system for a residential community in Yangzhou was designed and tested under winter conditions. The operating performance was evaluated and ground thermal imbalance problem was also analyzed based on the annual energy consumption of the air conditioning system of the community. The results showed that the ground source heat pump system requires 1087 vertical wells for heat transfer

the water temperature at the outlet of the buried pipe was 8.5–9.0 ℃

the coefficient of performance (COP) of heat pump unit was 3.67–4.17

and the system COP was 2.66. Based on the test data

it is concluded that the main reason for the low system COP is that the system operates at low temperature differences between inlet and outlet and large flow rate at low partial load rates

and thereby resulting in higher pump power consumption. Conversely

based on the combined annual air-conditioning energy consumption data of the community

it is concluded that the system's heat extraction in winter and the heat release in summer are unbalanced

and thereby resulting in a decrease in soil temperature.