Thermal Response Test for Borehole Thermal Properties in Tianjin

Abstract

Thermal response test (TRT) method has been developed over many years. It is still a useful way of determining the minimum length of the borehole heat exchanger (BHE) and is essential for the optimal design of the GSHP system. In this paper, TRT is used to estimate the ground thermal conductivities in a case study. Many factors should be considered in the engineering field to ensure the accuracy of TRT. The influence of flowing fluid velocity to the heat transfer rate of BHE is studied in this paper. By thermal response test, heat transfer performance of the higher velocity is better. Two different backfill materials are formed by fine sand and mixing fine sand with gravel. It is expected that variation of backfill material will prove to be increasingly effect for optimizing the operation of BHE, and consequently will minimize installation costs of geothermal heat pump systems. This paper has reference value for optimization design and sustainable operation of double U-typed GSHP system.