THERMAL RESPONSE TEST (TRT)

An important factor that affects the initial installation cost and the performance of a geothermal system is the proper calculation of the ground heat exchanger.
For small geothermal plants the thermal properties of the subsoil are empirically calculated, but for larger plants and to avoid over-dimensional or over-dimensional ground heat-exchangers, it is necessary to apply the Thermal Performance Test known as TRT (Thermal Response Test) or GRT (Geothermal Response Test).

The importance of TRT is so critical to the energy efficiency of the system, that in foreign countries for large geothermal plants, TRT is required by their local legislation. For example in the Federal District of Berlin, Germany, where TRT is required in installations over 30 Kw.

THE USUAL PRACTICE IS AS FOLLOWS:

DRILLING A TEST WELL

INSTALLATION OF THE GROUND HEAT EXCHANGER AND FILLING WITH CONDUCTIVE MATERIAL

CONDUCTING THE THERMAL RESPONSE TEST (TRT)

PROCESSING OF TRT RESULTS

INTRODUCTION OF TRT RESULTS TO SPECIAL SOFTWARE FOR GEOSTATISTICAL DIMENSIONING

The thermal efficiency test is a very important tool for the researcher as it:

– In the systems being designed, a test drill and the application of the thermal response test produce the safest results, thus avoiding over-dimensioning or sub-dimensioning of the system. This applies mainly to large plants.
– In already installed systems, the application of the thermal response test outputs results that are comparable to the original assumptions of the researcher and also checks for the correct construction of the ground heat exchanger.

The thermal response test transmits a constant amount of heat to the ground heat exchanger for a certain period of time (> 30h, depending on the diameter of the drill (ro), the thermal conductivity of the ground (λ) and the heat capacity (c)) and recording the inlet and output temperatures of the liquid draw conclusions about the thermal conductivity (λ) and thermal resistance (rb) of the exchanger.

With our proprietary equipment we offer our services for measuring geothermal heat response in any geothermal application and anywhere in Greece.