BHE logging and cement hydration heat analyses for the determination of thermo-physical parameters

To design an efficient and cost effective borehole heat exchanger (BHE), it is necessary to know the thermo-physical parameters of the subsurface at the project location. The quality management and the examination of existing BHEs are becoming particularly important with the increasing application of ground coupled heat pumps. The analysis of data collected from a BHE-logger (temperature-depth-measuring system) in a water-filled BHE allowed several geothermal parameters to be determined. A comparison of measurements obtained from the BHE-logs, geothermal response tests and laboratory soil tests indicated a good correlation. In addition to detecting hydraulic short circuits due to defects in the pipe system or backfill material, being relatively quick and easy to use, the BHE-logger can be a valuable tool in the long-term monitoring system and quality control of BHEs.