Abstract
The objective of this study is to investigate heat utilization systems using geothermal and ground source heat. A ground source heat pump (GSHP) uses pipes which are buried in the ground to extract heat from the ground. The conventional GSHP system adopts an indirect heat exchange method using a closed loop and vertical borehole system. On the other hand, the other GSHP system adopts the direct expansion method for exchange of heat with the underground. However, there is few report of a performance data of the GSHP using the direct expansion method so far. This paper described the experimental results of the performance not only of the conventional GSHP system but also of the direct expansion GSHP system.