A preliminary performance diagnosis of a ground source heat pump system under the winter operation mode in Hefei

The application and performance of ground source heat pump (GSHP) system in a community named Kexuejiayuan of Hefei, China are reported in this study. Based on the field test and operation record analysis of the GSHP system, it is found that the system has the problems of improper equipment matching and lacking of a reasonable operation strategy. The average temperature difference at the load side is 4.2°C. But the temperatures of the inlet and outlet water are both lower than the set value. The average temperature difference at the source side is obviously unsatisfying with the design condition. Soil heating capacity appeared to be insufficient during January and February while the load decreased to a lower level in March. The operating efficiency of the single pump on the load side and the source side of the system can reach 80% and 72%, respectively. In the condition of three-pump parallel operation, the test proved that there must be a significant parallel flow loss. Except for the existing problems, the system has great potential for energy saving and energy saving reform can be carried out. Combining with the actual situation of the project, the reform proposal is offered from the aspects of system match, monitoring and control systems, etc., aiming to optimise the performance of ground source heat pump. Concerning about the reduction of soil heating capacity in winter, the system can be supplemented with solar heating equipments. Formulating a reasonable operation strategy in separated period is also a viable way to reduce energy consumption.