Ground thermal properties is an important design parameter of ground-coupled heat pump system (GCHPs)

and it can be decided based on the data from in-situ thermal response test (TRT). Considering that constant heat input can seldom be ensured in TRT

this paper presents a novel method for determining parameters of rock-soil thermal properties by using simulated annealing algorithm (SAA). In the method

Green function used in cylinder source model (CSM) of borehole heat exchanger (BHE) accelerates calculation of inlet/outlet water temperatures based on the TRT system model

and RMSE distribution overcomes the ill-posed problem of parameter identification in inverse heat transfer analysis

which puts into effect of SAA. In a calculation sample based on TRT of variable heat input

annealing temperature decreases with identified parameters reaching agreement with true value individually

and the relative errors of ground thermal conductivity and volumetric heat capacity are respectively 4.1% and 1.3% by comparing with the value calculated based on national regulations on the same in-situ measuring location. At the same time

the effective heat resistance of BHE can be obtained in the process of ASS. In general

ASS used in the variable heat power TRT is proved to be successful

and the study is helpful for the design of BHE in GCHPs.