Comparison of calculated and measured ground thermal properties

Abstract

This paper presents a way of calculating the in-situ borehole ground thermal properties. For this procedure a U-tube ground heat exchanger embedded in a borehole is utilized, allowing hot water to circulate in the tube. The water is heated with constant power and its temperature is recorded in constant time intervals. Then the results are analyzed using the line source method. The formulas are solved using a simple excel program to derive the values of the thermal properties with a fitting technique. These results are compared with measured values of samples taken from the same area where the borehole is located. The comparison shows that only the experimental results analyzed with the theoretical model can give reliable values because the data concern the actual stage of compaction and moisture content of the soil.