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Multi-injection rate thermal response test with forced convection in a groundwater-filled borehole in hard rock

Liebel, Heiko; Javed, Saqib LU and Vistnes, Gunnar (2012) In Renewable Energy 48(December 2012). p.263-268
Abstract
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... (More)
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. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Convection, Ground-coupled heat pump, Multi-injection rate thermal response test
in
Renewable Energy
volume
48
issue
December 2012
pages
6 pages
publisher
Elsevier
external identifiers
  • scopus:84861818426
ISSN
0960-1481
DOI
doi:10.1016/j.renene.2012.05.005
language
English
LU publication?
yes
id
86bbd03a-a773-4aee-98ea-248d9d8b67bd
date added to LUP
2016-04-15 11:54:47
date last changed
2017-03-12 04:32:45
@article{86bbd03a-a773-4aee-98ea-248d9d8b67bd,
  abstract     = {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.},
  author       = {Liebel, Heiko and Javed, Saqib and  Vistnes, Gunnar},
  issn         = {0960-1481},
  keyword      = {Convection,Ground-coupled heat pump,Multi-injection rate thermal response test},
  language     = {eng},
  number       = {December 2012},
  pages        = {263--268},
  publisher    = {Elsevier},
  series       = {Renewable Energy},
  title        = {Multi-injection rate thermal response test with forced convection in a groundwater-filled borehole in hard rock},
  url          = {http://dx.doi.org/doi:10.1016/j.renene.2012.05.005},
  volume       = {48},
  year         = {2012},
}