Generic modelling to develop thermal yield nomograms for coaxial deep borehole heat exchangers (DBHE)

IF 16.4 1区化学 Q1 CHEMISTRY, MULTIDISCIPLINARY

Accounts of Chemical Research Pub Date : 2024-05-21 DOI:10.1144/qjegh2023-162

D. Banks, C. Brown, I. Kolo, G. Falcone

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Abstract

Numerical modelling of coaxial deep borehole heat exchangers (DBHE) can be resource-intensive. Simpler, transparent analytical models and nomograms would be valuable to developers and geologists for evaluating thermal output. An analytical computational model by Beier (2020) was used to produce nomograms of geothermal heat yield by systematically varying DBHE depth and rock thermal conductivity, while assuming two generic simplified DBHE designs, a geothermal gradient of 25°C/km and a fluid circulation rate of 5 L/s. Continuous 25-year heat yields from a 1000 m DBHE range from 27.3 to 54.8 kW for thermal conductivities of 1.6 to 3.6 W/m/K. For a 3000 m DBHE, they range from 165 kW to 281 kW. Effective borehole thermal resistance ( R b,eff ) increases strongly as DBHE depth increases, due to internal heat transfer between upflow and downflow elements. Simulations correspond well with results from industry-standard Earth Energy Designer software for shallow 200 m coaxial BHE. They modestly underestimate OpenGeoSys numerical modelled thermal yields by 2-4% for DBHE in the range 1000 to 3000 m depth. Modelled temperature evolution closely approximates an analytical “line heat source” approach, implying that simpler analytical approaches are plausible for DBHE simulation. Future research should focus on methods for forward quantification of R b,eff . Supplementary material: https://doi.org/10.6084/m9.figshare.c.7237887

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开发同轴深孔热交换器（DBHE）热产量名义图的通用模型

同轴深孔热交换器（DBHE）的数值建模需要大量资源。更简单、透明的分析模型和名义图对于开发人员和地质学家评估热输出非常有价值。Beier 的分析计算模型（2020 年）通过系统地改变 DBHE 的深度和岩石热传导率，同时假设两种通用的简化 DBHE 设计、25°C/km 的地热梯度和 5 升/秒的流体循环速率，生成了地热产出名义图。在导热系数为 1.6 到 3.6 W/m/K 的情况下，1000 米 DBHE 25 年的连续热量产出为 27.3 到 54.8 kW。3000 米 DBHE 的产热量范围为 165 kW 至 281 kW。有效井眼热阻（R b,eff）随着 DBHE 深度的增加而剧增，这是由于上流体和下流体之间的内部热传递造成的。模拟结果与工业标准 Earth Energy Designer 软件对 200 米同轴浅层 BHE 的模拟结果非常吻合。对于深度在 1000 米至 3000 米之间的 DBHE，模拟结果略微低估了 OpenGeoSys 数值模拟热产率 2-4%。模拟的温度变化与分析的 "线热源 "方法非常接近，这意味着对于 DBHE 模拟来说，更简单的分析方法是可行的。未来的研究应侧重于 R b,eff 的前向量化方法。补充材料：https://doi.org/10.6084/m9.figshare.c.7237887

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来源期刊

Accounts of Chemical Research 化学-化学综合

CiteScore

31.40

自引率

1.10%

发文量

312

审稿时长

2 months

期刊介绍： Accounts of Chemical Research presents short, concise and critical articles offering easy-to-read overviews of basic research and applications in all areas of chemistry and biochemistry. These short reviews focus on research from the author’s own laboratory and are designed to teach the reader about a research project. In addition, Accounts of Chemical Research publishes commentaries that give an informed opinion on a current research problem. Special Issues online are devoted to a single topic of unusual activity and significance. Accounts of Chemical Research replaces the traditional article abstract with an article "Conspectus." These entries synopsize the research affording the reader a closer look at the content and significance of an article. Through this provision of a more detailed description of the article contents, the Conspectus enhances the article's discoverability by search engines and the exposure for the research.