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Thermal Response Testing

A Thermal Response Test (TRT) involves applying a finite amount of heat energy into a closed loop borehole over a certain period of time (up to several days), while monitoring the rate at which heat dissipates into the surrounding ground. Appropriate analysis of the test data allows accurate values of ground thermal properties.

Why TRT is important for geothermal collector design?

The objective of TRTs is to determine site specific thermal properties of the ground around a closed loop borehole. Results of the tests allow a cost effective collector to be
developed by reducing the capital expenditure and optimising the number of boreholes to be completed, preventing long term operational problems, maximising design performance and reducing the overall operation costs of the system whilst meeting the required energy demands.

At what point in the project is the TRT test carried out?

A TRT test is carried out in the early phases of a ground source heat pump project installation of the ground source collector. Upon completion of a test borehole where a closed loop collector pipe has been placed. The TRT equipment is then used to carry out the TRT test.

What equipment is used?


Thermal response tests involve portable testing equipment typically in a small trailer which includes:

  • A 3kW heater unit
  • Water circulation pump
  • Buffer vessel
  • Flow and return pipe temperature sensors
  • Data transmission module

Additional information:

  • GeoServ’s TRT testing services are limited to undertaking the TRT test and do not include any borehole construction at any stage.
  • Thermal Response Test results are supplied to the client as a factual report and no advice on collector construction details are provided unless agreed with the client in writing.
  • TRT services supplied by GeoServ do not engage in the construction or completion of any ground source heat pump collectors unless agreed with the client in writing.