Shaanxi Hancheng Tianjiu Grouting Exploration Co., Ltd.
School of Human Settlements and Civil Engineering, Xi’an Jiaotong University

中深层同轴地埋管地热供热技术在我国北方城镇供热领域兴起并广泛应用。陕北地区地热资源丰富，但地温梯度略低且岩土热物性参数特性不同，地质参数影响中深层同轴地埋管的取热性能。采用OpenGeoSys开源数值模拟平台建立三维中深层同轴地埋管耦合地层传热计算模型，并基于陕北地区典型地质参数，研究不同设计参数对中深层同轴地埋管取热性能的影响及全生命周期技术经济性，优选出地热工程最佳工艺参数。结果表明，中深层同轴地埋管的外管径与埋深增大均能提升取热能力。相较于外管径，埋深对取热能力的提升效果更为显著，埋深从2500 m增加到3500 m，取热量增加了77.3%。依据工程实践，当外管外径×厚度大于177.80 mm×9.19 mm时所对应的平均能源成本因其钻井成本陡增而增大。在给定工况参数下，推荐中深层同轴地埋管的最佳外管外径×厚度为177.80 mm×9.19 mm，埋深为3 200 m，此时平均能源成本为0.524元/(kW·h)，经济效益最优。

The geothermal heating technology utilizing moderately deep coaxial borehole heat exchangers (MDCBHEs) has emerged and found extensive applications in urban heating in northern China. Despite abundant geothermal resources, northern Shaanxi exhibits slightly low geothermal gradients and distinct thermophysical properties of rocks and soils. Therefore, geological parameters influence the heat transfer performance of MDCBHEs in this area. Using OpenGeoSys, an open-source numerical simulation platform, this study established a three-dimensional calculation model for heat transfer between a MDCBHE and surrounding strata. Based on typical geological parameters in northern Shaanxi, the study investigated the influence of various design parameters on the heat transfer performance of MDCBHEs, as well as their techno-economic feasibility during their life cycle. Finally, this study selected the optimal parameters of MDCBHEs for geothermal engineering. Results indicate that increasing the outer diameter of outer pipes and the burial depth can both enhance the heat extraction capacity of a MDCBHE. Notably, compared to the outer diameter of outer pipes, the burial depth produced more significant effects on the capacity. Specifically, the nominal heat transfer capacity increased by 77.3% when the burial depth rose from 2500 m to 3500 m. Engineering practices reveal that when the outer diameter of outer pipes exceeds 177.80 mm × 9.19 mm, the average energy cost will increase due to a sharp rise in drilling costs. Under the specific operating parameters, this study recommends that the optimal design parameters of MDCBHEs should comprise an outer diameter of outer pipes of 177.80 mm × 9.19 mm and a burial depth of 3200 m. In this case, the average energy cost is 0.524 CNY/(kW·h), suggesting the optimal economic benefits.

陕西省重点研发计划高校联合项目(2023GXLH-032)

邹海江，李永鹏，张林，等. 陕北地区中深层同轴地埋管取热性能影响因素分析及优化[J]. 煤田地质与勘探，2024，52(1)：152−158.

ZOU Haijiang，LI Yongpeng，ZHANG Lin，et al. Influencing factor analysis and optimization of heat extraction performance of moderately deep coaxial borehole heat exchangers in northern Shaanxi, China[J]. Coal Geology & Exploration，2024，52(1)：152−158.