Low, JE, Loveridge, FA orcid.org/0000-0002-6688-6305, Powrie, W et al. (1 more author) (2015) A comparison of laboratory and in situ methods to determine soil thermal conductivity for energy foundations and other ground heat exchanger applications. Acta Geotechnica, 10 (2). pp. 209-218. ISSN 1861-1125
Abstract
Soil thermal conductivity is an important factor in the design of energy foundations and other ground heat exchanger systems. It can be determined by a field thermal response test, which is both costly and time consuming, but tests a large volume of soil. Alternatively, cheaper and quicker laboratory test methods may be applied to smaller soil samples. This paper investigates two different laboratory methods: the steady-state thermal cell and the transient needle probe. U100 soil samples were taken during the site investigation for a small diameter test pile, for which a thermal response test was later conducted. The thermal conductivities of the samples were measured using the two laboratory methods. The results from the thermal cell and needle probe were significantly different, with the thermal cell consistently giving higher values for thermal conductivity. The main difficulty with the thermal cell was determining the rate of heat flow, as the apparatus experiences significant heat losses. The needle probe was found to have fewer significant sources of error, but tests a smaller soil sample than the thermal cell. However, both laboratory methods gave much lower values of thermal conductivity compared to the in situ thermal response test. Possible reasons for these discrepancies are discussed, including sample size, orientation and disturbance.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © Springer-Verlag Berlin Heidelberg 2014. This is an author produced version of a paper published in Acta Geotechnica. The final publication is available at Springer via http://dx.doi.org/10.1007/s11440-014-0333-0. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Energy foundations; Ground source heat pumps; Needle probe; Thermal cell; Thermal conductivity |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Civil Engineering (Leeds) > Institute for Resilient Infrastructure (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 13 Oct 2016 14:45 |
Last Modified: | 16 Jan 2018 00:36 |
Published Version: | http://dx.doi.org/10.1007/s11440-014-0333-0 |
Status: | Published |
Publisher: | Springer Verlag |
Identification Number: | 10.1007/s11440-014-0333-0 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:104824 |