Abstract

This paper described the experimental results regarding the air conditioning performance of ground source heat pump that use direct expansion method. An underground heat exchanger consists of three parallel copper tubes and one insulated copper tube. The power output of the heat pump was 6.8 kW for cooling and 8.9 kW for heating. The underground heat exchangers were inserted into the three casing pipes made of steel which is 30 m depth. The three-parallel U-shaped underground heat exchanger were connected with the refrigerant circuit in the out-door unit. Experimental results are as follows. During the cooling operation, the average value of the output power, the power consumption, and COP was 1.9 kW, 0.3 kW, and 6.8, respectively. During the heating operation, the average value of the output power, the power consumption, and COP is 3.9 kW, 0.48 kW, and was 8.1, respectively.