63 Experimental Investigation of an Improved Thermal Response Test Equipment for Ground Source Heat Pump Systems

Thermal response test (TRT) is crucial for the determination of the ground thermal conductivity and the evaluation of the thermal performance of borehole heat exchangers (BHE). This paper is performed to develop a kind of improved TRT equipment based on the constant heating-temperature method (CHTM). A mathematical model to deal with test data is presented. Based on the measurement of the natural ground temperature distribution, an in-situ TRT case is conducted. The experimental results show that, compared with conventional TRT equipment with constant heating-flux method (CHFM), the improved equipment can operate effectively under the condition of heat injection and heat extraction and its test data can accurately reflect thermal properties of soils and the thermal performance of BHE. Finally, the advantages and disadvantages between CHTM and CHFM are compared.