Analysis of Influencing Factors on Soil Thermal Conductivity Test in Ground Source Heat Pump

A three dimensional numerical model of ground source heat pump system was established.The effects of testing time, starting time, borehole radius, initial ground temperature and heat injection rate on identified thermal conductivity of the deep ground soil were analyzed based Washers on the numerical model.The simulation results showed that thermal response test time should be more than 70 h; For cylinder-source model, with the Memory Support increase of the size of the borehole, the identified thermal conductivity gradually decreased; The initial temperature of ground soil has no effect on the result of thermal conductivity identification, but the testing precision of the initial temperature has larger effects to identification results when the parameter estimation method is adopted; For pure thermal conductivity model, heat injection rate has no effect on thermal conductivity identification results.