Pedchenko, O, Loveridge, F orcid.org/0000-0002-6688-6305, Woodman, N et al. (1 more author) (2019) Quantifying the effect of single fractures on the thermal performance of borehole heat exchangers. In: Proceedings EGC 2019. European Geothermal Congress 2019, 11-14 Jun 2019, The Hague, Netherlands. European Geothermal Energy Council ISBN 978-2-9601946-1-6
Abstract
Ground-source heat pump schemes for space conditioning and thermal storage increasingly use vertical borehole heat exchangers (VBHEs). Current models for VBHE performance often assume homogeneous ground conditions and the absence of flowing groundwater. However, in reality, the ground, especially bedrock, is commonly fractured. In this paper, numerical analysis is used to investigate a range of scenarios in which an open fracture with flowing groundwater may influence the thermal performance of a VBHE. It is intuitive to think that flowing groundwater always increases the heat transfer to and from a VBHE and hence improves their efficiency by reducing the temperature at the borehole wall. However, the results presented in this paper demonstrate that the presence of a fracture within permeable strata can also reduce the performance of a VBHE by locally lowering groundwater flow velocities in the rock matrix. Therefore the influence of a nearby open fracture may either improve or worsen the VBHE thermal performance depending on the fracture orientation relative to the borehole, the regional hydraulic gradient and the ratio of hydraulic permeabilities of the matrix and the fracture.
Metadata
Item Type: | Proceedings Paper |
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Authors/Creators: |
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Keywords: | aquifer; borehole heat exchangers; fracture; geothermal; ground source heat pump; groundwater; thermal transport |
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) |
Funding Information: | Funder Grant number Royal Academy of Engineering RF116 |
Depositing User: | Symplectic Publications |
Date Deposited: | 16 Apr 2019 10:42 |
Last Modified: | 28 Jan 2022 14:33 |
Published Version: | http://europeangeothermalcongress.eu/wp-content/up... |
Status: | Published |
Publisher: | European Geothermal Energy Council |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:144915 |