Thermal Response Test

A Thermal Response Test ( TRT for short ) is an in-situ test to determine the thermodynamic parameters of the subsurface.

execution

The TRT is carried out on a geothermal probe . A circulation pump and a heating element as well as sensors for recording the flow and return temperatures are connected. The fluid, i. d. Usually water, is pumped in a circle until the undisturbed subsurface temperature is reached. Then the heating element is switched on to heat the water. The water heated in this way flows through the geothermal probe and cools down in the process. The outlet temperature of the water from the probe is measured, the water runs through the heating element again and the cycle repeats itself.

A TRT should last 50 to 72 hours.

evaluation

The following parameters can be determined with a TRT:

• Thermal conductivity of the substrate,
• volumetric heat capacity ( heat capacity density heat storage number ),
• Heat transfer resistance of the borehole.

literature

• Stober, Ingrid; Bucher, Kurt: Geothermal. Springer-Verlag, Berlin Heidelberg, 2014, 86 ff. ISBN 978-3-642-24330-1