Jensen-Page, L, Loveridge, F orcid.org/0000-0002-6688-6305 and Narsilio, GA (2019) Thermal Response Testing of Large Diameter Energy Piles. Energies, 12 (4). 2700. ISSN 1996-1073
Abstract
Energy piles are a novel form of ground heat exchanger (GHE) used in ground source heat pump systems. However, characterizing the pile and ground thermal properties is more challenging than for traditional GHEs. Routine in-situ thermal response testing (TRT) methods assume that steady state conditions in the GHE are achieved within a few hours, whereas larger diameter energy piles may take days or even weeks, thereby incurring significant costs. Previous work on pile TRTs has focused on small diameters up to 450 mm. This paper makes the first rigorous assessment of TRT methods for larger diameter piles using field and laboratory datasets, the application of numerical and analytical modelling, and detailed consideration of costs and program. Three-dimensional numerical simulation is shown to be effective for assessing the data gathered but is too computationally expensive for routine practice. Simpler fast run time steady state analytical models are shown to be a theoretically viable tool where sufficient duration test data is available. However, a new assessment of signal to noise ratio (SNR) in real field data shows how power fluctuations cause increased uncertainty in long duration tests. It is therefore recommended to apply transient models or instead to carry out faster and more cost-effective borehole in-situ tests for ground characterization with analytical approaches for pile characterization.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
Keywords: | shallow geothermal; ground source heat pump; energy piles; foundations; thermal response test; numerical analysis |
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: | 30 Jul 2019 11:46 |
Last Modified: | 30 Jul 2019 11:46 |
Status: | Published |
Publisher: | MDPI |
Identification Number: | 10.3390/en12142700 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:149126 |