Xiangyu Wang , Ruiyong Mao , Hongwei Wu , Zujing Zhang , Rui Feng , Jiri Zhou , Yaya Chen
{"title":"Numerical study of influence of karst fracture water on heat transfer performance of borehole heat exchanger","authors":"Xiangyu Wang , Ruiyong Mao , Hongwei Wu , Zujing Zhang , Rui Feng , Jiri Zhou , Yaya Chen","doi":"10.1016/j.applthermaleng.2024.125065","DOIUrl":null,"url":null,"abstract":"<div><div>Groundwater flow within karst fractures can significantly enhance the heat exchange efficiency between a borehole heat exchanger (BHE) and the surrounding rock. The development of artificial fractures to intensify heat transfer between the BHE and rock has emerged as a promising direction in geothermal exploration. This study presents a three-dimensional finite element simulation model that integrates fracture flow with BHE heat transfer, accounting for various characteristics of horizontal fractures. Data analysis was conducted using range analysis and multi-criteria comprehensive evaluation, based on the principles of orthogonal experiments. The results indicate: (i) Fracture water flow substantially improves BHE heat transfer performance in summer, with even the lowest-performing configuration in the orthogonal test showing a 5.36 % increase in heat transfer per unit length of the BHE (HPLU) compared to the natural control group without fractures; (ii) The influence of different fracture characteristics on BHE heat transfer performance follows this order: fracture water velocity > fracture aperture > fracture depth > fracture flow direction > fracture water temperature; (iii) The optimal configuration enhances HPLU by 16.95 % over the natural control group, demonstrating that developing well-designed artificial fractures in karst regions can substantially improve BHE heat transfer efficiency.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"261 ","pages":"Article 125065"},"PeriodicalIF":6.1000,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Applied Thermal Engineering","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1359431124027339","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENERGY & FUELS","Score":null,"Total":0}
引用次数: 0
Abstract
Groundwater flow within karst fractures can significantly enhance the heat exchange efficiency between a borehole heat exchanger (BHE) and the surrounding rock. The development of artificial fractures to intensify heat transfer between the BHE and rock has emerged as a promising direction in geothermal exploration. This study presents a three-dimensional finite element simulation model that integrates fracture flow with BHE heat transfer, accounting for various characteristics of horizontal fractures. Data analysis was conducted using range analysis and multi-criteria comprehensive evaluation, based on the principles of orthogonal experiments. The results indicate: (i) Fracture water flow substantially improves BHE heat transfer performance in summer, with even the lowest-performing configuration in the orthogonal test showing a 5.36 % increase in heat transfer per unit length of the BHE (HPLU) compared to the natural control group without fractures; (ii) The influence of different fracture characteristics on BHE heat transfer performance follows this order: fracture water velocity > fracture aperture > fracture depth > fracture flow direction > fracture water temperature; (iii) The optimal configuration enhances HPLU by 16.95 % over the natural control group, demonstrating that developing well-designed artificial fractures in karst regions can substantially improve BHE heat transfer efficiency.
期刊介绍:
Applied Thermal Engineering disseminates novel research related to the design, development and demonstration of components, devices, equipment, technologies and systems involving thermal processes for the production, storage, utilization and conservation of energy, with a focus on engineering application.
The journal publishes high-quality and high-impact Original Research Articles, Review Articles, Short Communications and Letters to the Editor on cutting-edge innovations in research, and recent advances or issues of interest to the thermal engineering community.