Thermal response tests for the identification of soil thermal parameters: A review

Ground source heat pump systems (GSHPs) for soil heat utilization have been widely concerned in the world due to their energy saving, high efficiency, and no pollutant emission. The thermal parameters of the local soil must be known first when designing GSHPs, and the in-situ thermal response test (TRT) is currently the conventional method for determining their values. Given this, this paper deals with the related contents of parameter identification based on TRT from four aspects. First, various modeling methods for ground heat exchanger (GHE) and inversion algorithms are introduced and compared. Next, many factors that influence the identification accuracy are summarized, including test conditions, external disturbance, groundwater seepage and subsurface natural convection. Then, the negative in-fluence of correlation between parameters on identification results is analyzed, and the research progress of the uncertainty assessment of identification results is introduced, which can improve the reliability of the results. Furthermore, the characteristics of various advanced TRT setups are also summarized. Finally, several imperfects and objectives for improving the reliability of parameters identification are discussed. This work provides useful information for improving the identification accuracy of soil thermal pa-rameters so that the GHSPs can be designed more reliably. (c) 2020 Elsevier Ltd. All rights reserved.