Analysis of the first thermal response test in Algeria

Ground source heat pumps (GSHPs) mean attractive heating and cooling systems. Optimum design of a borehole heat exchanger (BHE), as the outer part of a GSHP heating system, requires knowledge of the thermal properties of the soil. Those data, the effective thermal conductivity of the soil λ eff and the average temperature of the soil T 0 enable us to determine the necessary number and depth of boreholes. The determination of thermal conductivity of the soil in laboratory experiments does not usually coincidence with the data under in situ conditions. Therefore, an in situ method of experimental determination of these parameters, thermal response testing (TRT) is used primarily for in situ determination of design data for BHEs. In this study, which was the first TRT in Algeria (Tlemcen site), the purpose was to determine the effective ground thermal conductivity. Measured data were evaluated by the line source model. Used method and performed evaluation are presented for a borehole drilled in clay, silt, and sand. The resulting effective ground thermal conductivity was 1.364 W/m K and the borehole thermal resistance was 0.18 K/(W/m).