Thermal response test and numerical analysis based on two models for ground-source heat pump system

Thermal response test (TRT) is becoming increasingly popular in obtaining the ground thermal properties as well as evaluating the performance of the ground heat exchanger (GHE) that determines the properties of ground source heat pump (GSHP) system. This study investigated a practical engineering project, which is located in Shijiazhuang, Hebei Province, as an example to test the ground thermal properties. A popular constant heating-flux method (CHFX) was used with the heat load of 3.6 kW and 8.4 kW, respectively. This investigation compared and analyzed the ground thermal properties by the line source model (LSM) and the cylinder source model (CSM). This study also conducted the sensitivity analysis on different data intervals by fixing starting time or ending time. Moreover, a new method (Bland-Altman analysis) was proposed to analyze and determine the agreement between simulated and experimental data. The results showed that the new method performed well in evaluating the agreement and could help to properly choose the test duration and data interval for thermal response test.