A METHOD TO ESTIMATE GROUND THERMAL CONDUCTIVITY IN USING SPIRAL COIL TYPE GROUND HEAT EXCHANGER

This paper presents an experimental study on evaluation of thermal response of spiral coil type ground heat exchanger (GHE). This GHE was installed partially saturated landfill ground which was composed of silt and clay in the runway area of Incheon International Airport. Thermal response test (TRT) was conducted for more than 65 hours under the continuous operation condition. Ground thermal conductivity was derived from line source theory which was usually appropriate to line type GHEs such U, W and 2U types. A reasonable method to derive ground thermal conductivity from infinite line source theory with coil type GHE was introduced, and compared with real ground thermal conductivity.