Abstract
Ground source heat exchangers are used for utilization of ground source heat. This underground heat exchanger is usually installed in the ground at a depth of about 100 m vertically. However, high installation costs prevent popularization of underground heat utilization in Japan. The Horizontal Directional Drilling (HDD) costs only a third of the vertical drilling. We set the ground source heat exchanger horizontally inside the permeable layer by HDD at Saga. High heat exchange rate at heat exchanger can be expected by the groundwater flow.Experiment was carried out with constant inlet temperature and flow rate. The heat transfer rate was about 20 - 30 W/m. From the numerical simulation results, the groundwater flow velocity would be below about 2.0×10-6 m/s.
