EXPERIMENTAL STUDY OF HEAT TRANSFER OF BOREHOLES IN CLOSED LOOP VERTICAL GROUND HEAT EXCHANGERS IN A COLD WINTER AND HOT SUMMER AREA

As a renewable energy technology for space heating and cooling, ground source heat pump(GSHP) systems have been encouraged to be used by China government. In Jiangsu Province, located at the East China, the zone with hot summer and cold winter, the number of closed loop vertical ground source heat pump systems is increasing rapidly in recent years. Accurate Soil property is helpful for properly using ground source heat pump. This paper reported the preliminary results investigate the soil parameters and the potential to use ground heat source pump for a stage of long term project. Thermal response and measured soil samples from borehole were used to measure the conductivity of soil and results are compared. Results show that thermal response measured synthetic soil conductivity is higher than that measured samples directly. And the borehole close to river has higher water content and higher synthetic conductivity which is due to the enhancement of heat transfer by slowly water flow. Results can help to guide large scale usage of Ground source heat pump.