Borefield Design and Enhanced Thermal Response Test for the Energy Building of the University of Genova

Abstract. The Thermal Response Test (TRT) is a well known experimental technique for assessing the behaviour of borehole heat exchangers (BHE) for Ground Coupled Heat Pumps (GCHP) applications which is based on the injection of a constant heat rate in the ground while the carrier fluid is circulated in a pilot BHE. The TRT technique is here further developed in order to cope with non constant heat injection rates, according to a new method submitted for Italian patenting. The measurements have been carried out in the Savona Campus of the University of Genova, where a high efficiency new building is going to be realized. The experimental method revealed to be able to reconstruct the ground and BHE thermal properties also when a long series of heat pulses is applied for several days, thus simulating the real operating conditions of GCHPs. The measurements revealed particularly high values of the apparent ground thermal conductivity as could be expected due to the particular geological configuration of the alluvial measuring site. In spite of this specific condition (groundwater presence) the method demonstrated to be reliable for inferring the ground thermal properties under heating cycles similar to those pertaining the real GCHP working modes