Thermal analysis of medium-depth borehole heat exchanger coupled layered stratum thermal conductivity

Shihao Dong, Yuelong Yu, Bingxue Li and Long Ni

Renewable Energy, 2025, vol. 246, issue C

Abstract: Medium-depth coaxial borehole heat exchanger is a crucial option for low-carbon heating. However, the complex and variable nature of medium-deep formations poses challenges for accurate thermal conductivity determination, and its correlation with heat transfer mechanisms remains unclear. Hence, a thermal conductivity model incorporating temperature corrections and lithological variations was developed and integrated into a layered analytical heat transfer model. Model analysis shows that strata thermal conductivity and temperature both have significant effects on heat extraction. Geological tests and applications based on Shenyang case found that due to good thermal conductivity of rock skeleton (gneiss), low porosity (1.8 %) and no mud, maximum value of 3.34 W m−1 K−1 was observed near 1063.9–1068.8 m. The average thermal conductivity is 2.58 W m−1 K−1. Formations with low porosity, low permeability, and low mud-content are denser, which favors heat conduction, contrary to hydro-geothermal wells that rely on highly porous and fractured formations. The deviation between the calculated results and thermal response test from two regions did not exceed 5.21 %, achieving a high precision. This method enables direct determination of formation thermal properties based on well-logging, providing a convenient and engineering-friendly approach.

Keywords: Coaxial borehole heat exchanger; Stratum thermal conductivity; Heat transfer model; Geologic analysis (search for similar items in EconPapers)
Date: 2025
References: Add references at CitEc
Citations:

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0960148125005427
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:renene:v:246:y:2025:i:c:s0960148125005427

DOI: 10.1016/j.renene.2025.122880

Access Statistics for this article

Renewable Energy is currently edited by Soteris A. Kalogirou and Paul Christodoulides

More articles in Renewable Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu ().