4521 -- In Situ Measurement of Ground Thermal Conductivity: A Dutch Perspective

Determination of the ground's thermal conductivity is a significant challenge facing designers of ground-source heat pump (GSHP) systems applied in commercial buildings. The ground heat exchanger size and cost are highly dependent on the ground thermal properties. In order to be able to predict ground thermal properties, an experimental apparatus has been built capable of imposing a heat injection or heat extraction pulse on a test borehole and measuring its temperature response. Analysis of a detailed in situ test using a line source approach and bootstrap uncertainty analysis is presented. Results are compared with a "traditional estimate" based on a detailed geological description and with results of laboratory measurements. These results are also compared to those determined using parameter estimation in conjunction with a two-dimensional finite volume model.

Units: Dual