The soil thermal properties are obt

The soil thermal properties are obtained using field testing methods. The field test method is to bury a U-shaped tube in the drilled hole and backfill it according to the design requirements (this hole can also be used as a branch of the ground-source heat pump underground heat exchanger in the future). Begin heating the water in the pipe for a certain time from a certain moment, and measure the inlet and outlet water temperature, water flow and heating power, etc., and then use the selected buried pipe heat transfer model to calculate the average temperature of the buried pipe fluid, and The average temperature of the measured inlet and outlet water temperature of the buried pipe is compared. Using the optimization theory, adjust the thermophysical and physical properties of the heat transfer model to minimize the error between the average temperature of the fluid calculated by the model and the measured average temperature of the fluid. At this time, the corresponding physical properties are the final values. The optimized value of the geophysical and thermal physical parameters of the model, and its optimization objective function is: