Multi-injection rate thermal response test with forced convection in a groundwater-filled borehole in hard rock
Artikel i vetenskaplig tidskrift, 2012

Convection is shown in earlier studies to improve the thermal contact between heat exchanger and borehole wall in water-filled boreholes. This study investigates the effect of convection on the required borehole length for a ground-coupled heat pump installation. Artificial convection was induced by an ordinary groundwater pump during a multi-injection rate thermal response test (MIR-TRT). For comparison, a second MIR-TRT was performed without pumping of groundwater. The required borehole length was estimated for a ground-coupled heat pump installation supplying a Swedish single-family house. The estimates are based on the results from the MIR-TRTs for thermal conductivity and borehole resistance. The results show linear decrease in required borehole length with increasing heat input rate during the MIR-TRT without pumping of groundwater due to buoyancy-driven convection. An artificial convection stronger than buoyancy-driven convection during the MIR-TRT with pumping of groundwater reduced the required borehole length by 9 %-25 % depending on the heat input rate.

Multi-injection rate thermal response test

Hard rock


Ground-coupled heat pump


H. T. Liebel

Norges teknisk-naturvitenskapelige universitet

Saqib Javed

Chalmers, Energi och miljö, Installationsteknik

G. Vistnes

Norges teknisk-naturvitenskapelige universitet

Renewable Energy

0960-1481 (ISSN) 18790682 (eISSN)

Vol. 48 263-268


Hållbar utveckling


Building Futures (2010-2018)






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