In-Situ Thermal Response Testing – New Developments

The number of installations of ground source heat pump (GHSP) systems is rapidly growing in Switzerland. For any installation it is critical to have a correct estimation of the ground thermal properties to ensure optimal energy savings and for larger developments the in-situ thermal response test (TRT) provides a cost-effective method to achieve this. The authors have developed a compact mobile test device for the TRT, where all the required components are held in a suitcase-sized container. The compact module has been equipped with a modem to facilitate remote data-monitoring. This addition has enabled the engineer to overview the results in real time and to switch the heater on and off via a mobile phone, something that has reduced the time spent on site and therefore also the cost. The new compact test device has been used to determine the thermal conductivity for several larger GHSP systems in Switzerland and France and have shown equivalent results to previous trailer-sized equipments. The development and operation of the device is described together with a case study of a performed in-situ thermal response test.