 Influence of moisture on heat transfer of ground heat exchangers in unsaturated soilsSiyuan Li, Tiemeng Sun, Yufang Du and Min Li Renewable Energy, 2022, vol. 193, issue C, 1177-1185 Abstract: The applications of ground heat exchangers (GHEs) in arid and semi-arid zones require knowledge about the effects of moisture on heat transfer in the ground. To evaluate the influence of moisture, this study integrates a finite line-source model, a normalized thermal conductivity model, and a saturation degree model. A normalized temperature difference, defined as a temperature-difference ratio (TDR) of unsaturated to saturated soils, is proposed to characterize the reduction in heat transfer of GHEs in unsaturated soils. The modeling results show that the effective thermal conductivity of soils increases with saturation degree in a nonlinear way, thus leading to the nonlinear effect of moisture on heat conduction of GHEs: the influence of moisture on heat transfer is more significant in low-moisture soils (Sl < 0.5) than that in high-moisture soils (Sl > 0.5). This result implies that the design length of borehole GHEs is highly sensitive to the degree of saturation in low-moisture soils. Keywords: Ground heat exchanger; Moisture; Unsaturated soils; Ground heat storage; Ground-coupled heat pump (search for similar items in EconPapers) Downloads: (external link) Related works: Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text Persistent link: https://EconPapers.repec.org/RePEc:eee:renene:v:193:y:2022:i:c:p:1177-1185 DOI: 10.1016/j.renene.2022.04.073 Access Statistics for this article Renewable Energy is currently edited by Soteris A. Kalogirou and Paul Christodoulides More articles in Renewable Energy from Elsevier |
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