LAPSE

LAPSE:2019.0204
Published Article
LAPSE:2019.0204
Dimensionless Maps for the Validity of Analytical Ground Heat Transfer Models for GSHP Applications
January 31, 2019
This article provides plain and handy expressions to decide the most suitable analytical model for the thermal analysis of the ground source in vertical ground-coupled heat pump applications. We perform a comprehensive dimensionless analysis of the reciprocal deviation among the classical infinite, finite, linear and cylindrical heat source models in purely conductive media. Besides, we complete the framework of possible boreholes model with the “hollow” finite cylindrical heat source solution, still lacking in the literature. Analytical expressions are effective tools for both design and performance assessment: they are able to provide practical and general indications on the thermal behavior of the ground with an advantageous tradeoff between calculation efforts and solution accuracy. This notwithstanding, their applicability to any specific case is always subjected to the coherence of the model assumptions, also in terms of length and time scales, with the specific case of interest. We propose several dimensionless criteria to evaluate when one model is practically equivalent to another one and handy maps that can be used for both design and performance analysis. Finally, we found that the finite line source represents the most suitable model for borehole heat exchangers (BHEs), as it is applicable to a wide range of space and time scales, practically providing the same results of more complex models.
Keywords
analytical models, dimensionless analysis, finite cylindrical heat source, finite linear heat source, ground heat transfer, ground-source heat pump systems, infinite cylindrical heat source, infinite linear heat source, purely-conductive media
Suggested Citation
Conti P. Dimensionless Maps for the Validity of Analytical Ground Heat Transfer Models for GSHP Applications. (2019). LAPSE:2019.0204
Author Affiliations
Conti P: BETTER—Building Energy Technique and Technology Research Group, University of Pisa, Largo Lucio Lazzarino, Pisa 56122, Italy; DESTEC—Department of Energy, Systems, Territory and Constructions Engineering, University of Pisa, Largo Lucio Lazzarino, Pis [ORCID]
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Journal Name
Energies
Volume
9
Issue
11
Article Number
E890
Year
2016
Publication Date
2016-10-29
Published Version
ISSN
1996-1073
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Original Submission
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PII: en9110890, Publication Type: Journal Article
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LAPSE:2019.0204
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doi:10.3390/en9110890
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Jan 31, 2019
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CC BY 4.0
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Jan 31, 2019
 
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Original Submitter
Calvin Tsay
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