Effects of mechanical ventilation and heat exchange pipe system on heat transfer efficiency in high geothermal tunnel

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology Pub Date : 2025-06-18 DOI:10.1016/j.tust.2025.106815

Hongzhi Cui , Chen Ding , Changqing Xia , Peng Peng , Xiaohua Bao , Xiangsheng Chen

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引用次数: 0

Abstract

This study proposed an innovative integrated approach for cooling and collecting geothermal energy in high geothermal tunnels by deploying a heat exchange pipe (HEP) system. A numerical model for the excavated working face was formulated by utilizing on-site data from a plateau-high geothermal tunnel. The accuracy of the developed model was validated with field measurements of temperature. Subsequently, an analysis of the cooling effects through heat transfer was conducted considering mechanical ventilation by investigating the impact of the cooling mode, pipe spacing, pipe inner diameter, water circulation velocity, ventilation air velocity, surrounding rock temperature, and the distance between the ventilation pipe outlet and the excavation face. The results suggest that the abundant geothermal energy in high geothermal tunnels can be harvested using only pumps, which yield a relatively high coefficient of performance (COP). Furthermore, the ventilation airflow demonstrates the maximum cooling impact on the temperature of both the excavation surface as well as the surrounding air. The buried pipe system and the ventilation system together reduce the average air temperature from 30 °C to under 26 °C in just one hour. Based on a holistic assessment of heat exchange efficiency and energy efficiency ratio, the suggested pipe spacing is 1.5–3 m, with a recommended inner diameter of 50 mm for the HEPs alongside a suitable circulating water flow rate of 0.6–1 m/s.

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机械通风换热管系统对高温地热隧道换热效率的影响

本研究提出了一种利用热交换管（HEP）系统对高地热隧道进行冷却和地热能收集的创新方法。利用某高原高温地热隧道的现场数据，建立了开挖工作面数值模型。通过现场温度测量验证了所建立模型的准确性。随后，通过考察冷却方式、管道间距、管道内径、水循环速度、通风风速、围岩温度以及通风管道出口与开挖工作面距离的影响，分析了考虑机械通风的换热冷却效果。结果表明，高地热隧道中丰富的地热能可以仅利用水泵进行采收，水泵具有较高的效能系数（COP）。此外，通风气流对开挖表面温度和周围空气温度的冷却影响最大。地埋管系统和通风系统在1小时内将平均气温从30℃降至26℃以下。综合考虑换热效率和能效比，建议管道间距为1.5-3 m，高效能热泵内径为50 mm，循环水流速为0.6-1 m/s。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Tunnelling and Underground Space Technology 工程技术-工程：土木

CiteScore

11.90

自引率

18.80%

发文量

454

审稿时长

10.8 months

期刊介绍： Tunnelling and Underground Space Technology is an international journal which publishes authoritative articles encompassing the development of innovative uses of underground space and the results of high quality research into improved, more cost-effective techniques for the planning, geo-investigation, design, construction, operation and maintenance of underground and earth-sheltered structures. The journal provides an effective vehicle for the improved worldwide exchange of information on developments in underground technology - and the experience gained from its use - and is strongly committed to publishing papers on the interdisciplinary aspects of creating, planning, and regulating underground space.