Research on Design Method for Optimal Flow Rate of U-shaped Geothermal Well Based on Exergy Analysis

Autor: Dong Xiao, Jiaxin Xu, Tianduoyi Wang, Chun Cai, Li Li, Jianhong Liu
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Energy Exploration & Exploitation, Vol 40 (2022)
Druh dokumentu: article
ISSN: 0144-5987
2048-4054
01445987
DOI: 10.1177/01445987211066340
Popis: Closed-loop U-shaped geothermal wells show great potential owing to their special well-depth structure, which can provide a good flow rate and heat extraction. However, no advanced process parameter optimization method is available for U-shaped geothermal wells. To effectively describe the heat transfer processes of U-shaped geothermal wells, an analytical solution that couples transient heat conduction in the surrounding soil (or rocks) with the quasisteady heat transfer process in boreholes was developed. This modelling approach depends on many common elements, such as the thermophysical properties of the working fluid and series of resistances for various elements in the wellbore. Subsequently, based on the exergy analysis method, the optimal operating flow rate was defined and a design method for the optimal flow rate was developed. Results indicate that to obtain the maximum exergy efficiency, different optimal flow rates for the U-shaped geothermal well are achieved at different stages of the heating period. This findings of this study expand the research ideas of the process parameter optimization of U-shaped geothermal wells and provide a theoretical basis for developing an optimal circulating-flow-rate design for U-shaped geothermal wells.
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