[A-HW25] Near Surface Investigation and Modeling for Groundwater Resources Assessment and Conservation

[AHW25-P06] A New Analytical Solution for Thermal Response Tests Considering Finite Borehole Radius and Grout Heat Capacity

*Ying-Fan Lin¹, Hsiang-Wen Wang¹ (1.Chung Yuan Christian University)

Keywords:Geothermal boreholes, Thermal response test, Grout heat capacity, Laplace transform

This study presents a new analytical solution that accounts for the effects of the finite radius of geothermal heat transfer boreholes and the heat capacity of the grouting material on the temporal and spatial temperature distribution observed during thermal response tests (TRT). The new solution explores how the thermal properties of the grouting material (i.e., thermal capacity of the grout) effect the estimation of soil thermal properties in TRT. The solution can be derived analytically using the Laplace transform method. Sensitivity analysis is performed to investigate the effects of thermal properties of ground and grouting material on the temperature changes produced by TRTs. The results show that effective borehole thermal resistance is the most sensitive parameter, followed by the thermal conductivity and the thermal capacity of the ground, while the thermal capacity of the grout is insensitive. In addition, the new analytical solution is utilized to analyze the time-temperature data obtained from TRTs conducted in at the Shandong Institute of Architecture and Engineering, China. The results show that the new solution can better capture the temperature data at early times as compared with the past solutions.