Calculation and analysis of in-situ rock-soil thermal response test and heat transfer capacity

The paper aims to measure a reliable ground thermal conductivity to provide a basic parameter for proper design of borehole heat exchangers.Taking a ground source heat pump(GSHP) project as an example,based on the principle of soil thermal response,the paper presents a method of in-situ thermal response test and calculates and analyzes the rock-soil thermal conductivity and heat exchange of unit borehole depth.The results show that the average ground thermal conductivity of the test site is 2.23 W/(m·K).Compared with the recommend values of similar rock-soil indicates that the test values are reliable.The average heat exchange of unit borehole depth is 57.71 W/m.The rock-soil has a better heat capacity.Moreover,to select optimization zone,the geology of construction site should be explored comprehensively before the design of GSHP system.To decrease the hidden dangers of soil heat balance,it is recommended that the GSHP system should be operated both in summer and in winter.