Advanced

The influence of the thermosiphon effect on the thermal response test

Gehlin, S E A; Hellström, Göran LU and Nordell, B (2003) In Renewable Energy 28(14). p.2239-2254
Abstract
The issue of natural and forced groundwater movements, and its effect on the performance of ground heat exchangers is of great importance for the design and sizing of borehole thermal energy systems (BTESs). In Scandinavia groundwater filled boreholes in hard rock are commonly used. In such boreholes one or more intersecting fractures provide a path for groundwater flow between the borehole and the surrounding rock. An enhanced heat transport then occurs due to the induced convective water flow, driven by the volumetric expansion of heated water. Warm groundwater leaves through fractures in the upper part of the borehole while groundwater of ambient temperature enters the borehole through fractures at larger depths. This temperature driven... (More)
The issue of natural and forced groundwater movements, and its effect on the performance of ground heat exchangers is of great importance for the design and sizing of borehole thermal energy systems (BTESs). In Scandinavia groundwater filled boreholes in hard rock are commonly used. In such boreholes one or more intersecting fractures provide a path for groundwater flow between the borehole and the surrounding rock. An enhanced heat transport then occurs due to the induced convective water flow, driven by the volumetric expansion of heated water. Warm groundwater leaves through fractures in the upper part of the borehole while groundwater of ambient temperature enters the borehole through fractures at larger depths. This temperature driven flow is referred to as thermosiphon, and may cause considerable increase in the heat transport from groundwater filled boreholes. The thermosiphon effect is connected to thermal response tests, where the effective ground thermal conductivity is enhanced by this convective transport. Strong thermosiphon effects have frequently been observed in field measurements. The character of this effect is similar to that of artesian flow through boreholes. (C) 2003 Elsevier Science Ltd. All rights reserved. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
thermosiphon, groundwater, borehole, thermal, thermal response test, conductivity, ground heat exchanger
in
Renewable Energy
volume
28
issue
14
pages
2239 - 2254
publisher
Elsevier
external identifiers
  • wos:000184107900007
  • scopus:0037932347
ISSN
0960-1481
DOI
language
English
LU publication?
yes
id
d43f360a-c231-4bab-befa-148357d4b97a (old id 306246)
date added to LUP
2007-09-03 10:03:49
date last changed
2018-05-29 10:38:10
@article{d43f360a-c231-4bab-befa-148357d4b97a,
  abstract     = {The issue of natural and forced groundwater movements, and its effect on the performance of ground heat exchangers is of great importance for the design and sizing of borehole thermal energy systems (BTESs). In Scandinavia groundwater filled boreholes in hard rock are commonly used. In such boreholes one or more intersecting fractures provide a path for groundwater flow between the borehole and the surrounding rock. An enhanced heat transport then occurs due to the induced convective water flow, driven by the volumetric expansion of heated water. Warm groundwater leaves through fractures in the upper part of the borehole while groundwater of ambient temperature enters the borehole through fractures at larger depths. This temperature driven flow is referred to as thermosiphon, and may cause considerable increase in the heat transport from groundwater filled boreholes. The thermosiphon effect is connected to thermal response tests, where the effective ground thermal conductivity is enhanced by this convective transport. Strong thermosiphon effects have frequently been observed in field measurements. The character of this effect is similar to that of artesian flow through boreholes. (C) 2003 Elsevier Science Ltd. All rights reserved.},
  author       = {Gehlin, S E A and Hellström, Göran and Nordell, B},
  issn         = {0960-1481},
  keyword      = {thermosiphon,groundwater,borehole,thermal,thermal response test,conductivity,ground heat exchanger},
  language     = {eng},
  number       = {14},
  pages        = {2239--2254},
  publisher    = {Elsevier},
  series       = {Renewable Energy},
  title        = {The influence of the thermosiphon effect on the thermal response test},
  url          = {http://dx.doi.org/},
  volume       = {28},
  year         = {2003},
}