Geothermics最新文献_第6页

Evaluation of heat extraction using compact shallow ground heat panels with the interaction of stormwater- a residential case study 利用紧凑型浅层地热板与雨水相互作用进行热提取的评价——一个住宅案例研究

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2025-12-12 DOI: 10.1016/j.geothermics.2025.103563

Mostafa Mohamed , Abubaker Abdullah , Omar El-Kezza , Mohamad Abdel-Aal , Alma Schellart , Simon Tait

A bespoke parallel shallow horizontal Ground Source Heat Pump system (GSHP) with a small footprint (50 m²) was installed to provide space heating and domestic hot water for a residential house in the North of England. The shallow GSHP was combined with a storm water infiltration trench and both were installed with an adjacent control house which was fitted with a standard gas boiler for space heating and hot water. Up to 350 metres of High Density Polyethylene (HDPE) pipe with an external diameter of 40 mm connected in 2 parallel compact panels was used at the front and back of the house with the GSHP. The paper aims to (i) present data for the response of the ground to heat extraction using shallow ground heat panels and (ii) analytically model the heat gain in the ground heat exchanger panel, accounting for the thermal resistivity between the heat exchanger pipes and the surrounding soil, as well as the varriations in ground temperature and thermal conductivity. Internal and external ambient air temperatures, rainfall, coolant flow rate, coolant temperature, ground temperature and ground water level were monitored for a full year. The comprehensive field data were analysed to demonstrate the ground response and evaluate the performance of the shallow parallel ground heat extraction panels. Field data indicated that rainwater enhanced heat extraction and caused temporary increase in the ground temperature. Results from the analytical model are compared with measured temperature at five points on the ground heat extraction panel. The model showed good levels of predictive performance of the coolant temperature along the ground panel. However, it was noted that the model overestimates the coolant temperature at the centre point of the ground panel.

一个定制的平行浅水平地源热泵系统（GSHP）占地面积小（50平方米），为英格兰北部的一座住宅提供空间供暖和生活热水。浅层地源热泵与雨水渗透沟相结合，并在相邻的控制室安装了标准燃气锅炉，用于空间供暖和热水。高达350米的高密度聚乙烯（HDPE）管，外径40毫米，连接在两个平行的紧凑板上，与地源热泵一起用于房屋的前部和后部。本文的目的是(i)提供地表对利用浅层地面热板采热的响应数据，（ii）分析模拟地表热交换器板中的热增益，考虑热交换器管道与周围土壤之间的热电阻率，以及地温和导热系数的变化。全年监测内外环境空气温度、降雨量、冷却剂流量、冷却剂温度、地温和地下水位。通过对现场综合数据的分析，论证了浅层平行采热板的地面响应，并对其性能进行了评价。野外资料表明，雨水增强了采热，引起地温暂时升高。分析模型的计算结果与地面采热板上五个点的实测温度进行了比较。该模型显示了沿地面面板的冷却剂温度的良好预测性能。然而，有人指出，该模型高估了地面面板中心点的冷却剂温度。

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引用次数: 0

Development and validation of regression model via machine learning to estimate thermal conductivity and heat flow using igneous rocks from the Dikili-Bergama geothermal region, Western Anatolia 通过机器学习开发和验证回归模型，以估计来自安纳托利亚西部Dikili-Bergama地热区的火成岩的导热系数和热流

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2025-12-09 DOI: 10.1016/j.geothermics.2025.103567

Tolga Ayzit , Onur Güngör Şahin , Selçuk Erol , Alper Baba

Thermal conductivity is a fundamental parameter that significantly influences the thermal regime of the lithosphere. It plays a crucial role in a variety of geological applications, including geothermal energy exploration, igneous system assessment, and tectonic modeling. In this study, a machine learning approach is used to predict the thermal conductivity of igneous rocks based on the composition of major oxides. A total of 488 samples from different regions of the world were analyzed. The thermal conductivity values ranged from 1.20 to 3.74 Wm⁻¹ K⁻¹ and the mean value was 2.61 Wm⁻¹ K⁻¹. The Random Forest (RF) algorithm was used, resulting in a high coefficient of determination (R² = 0.913 for training and R² = 0.794 for testing) and a root mean square error (RMSE) of 0.112 and 0.179, respectively. Significance analysis of the traits identified SiO₂ (>40 %), Na₂O (>15 %) and Al₂O₃ (>10 %) as the most influential predictors. The study presented results from the Western Anatolia region, where felsic rocks had the highest thermal conductivity (mean = 2.69 Wm⁻¹K⁻¹) compared to mafic (mean = 2.34 Wm⁻¹K⁻¹) and ultramafic rocks (mean = 2.39 Wm⁻¹K⁻¹). In addition, the study evaluated the predictive capabilities of machine learning models for the igneous rocks of the Dikili-Bergama region and compared the results with those of saturated models. Using these data, we calculated heat flow values of up to 400 mWm⁻² under saturated conditions in western Anatolia. These results highlight the value of integrating geochemical data with machine learning to improve geothermal resource exploration and lithospheric modeling.

热导率是影响岩石圈热状态的基本参数。它在地热能勘探、火成岩系统评价和构造模拟等多种地质应用中发挥着至关重要的作用。在这项研究中，基于主要氧化物的组成，使用机器学习方法来预测火成岩的导热性。总共分析了来自世界不同地区的488个样本。热导率为1.20 ~ 3.74 Wm−1 K−1，平均值为2.61 Wm−1 K−1。采用随机森林（Random Forest， RF）算法，具有较高的决定系数（训练R²= 0.913，检验R²= 0.794），均方根误差（RMSE）分别为0.112和0.179。对这些性状的显著性分析发现SiO₂（> 40%）、Na2O （> 15%）和Al₂O₃（> 10%）是最具影响力的预测因子。研究结果来自西部安纳托利亚地区，与基性岩（平均2.34 Wm−¹K−¹）和超基性岩（平均2.39 Wm−¹K−¹）相比，长英质岩的导热系数最高（平均2.69 Wm−¹K−¹）。此外，该研究还评估了机器学习模型对Dikili-Bergama地区火成岩的预测能力，并将结果与饱和模型进行了比较。利用这些数据，我们计算了安纳托利亚西部饱和条件下高达400 mWm−2的热流值。这些结果突出了地球化学数据与机器学习相结合在地热资源勘探和岩石圈建模方面的价值。

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引用次数: 0

Unveiling geothermal potential in Pinrang regency, Indonesia: Integrated geochemical and geoelectrical characterization 揭示印尼平让地区的地热潜力：综合地球化学和地电学表征

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2025-12-08 DOI: 10.1016/j.geothermics.2025.103565

Muhammad Altin Massinai , Hendra Grandis , Ilham Arisbaya , Muh.Farid Wajedy , Fahruddin Fahruddin , Muhammad Fawzy Ismullah Massinai

Geothermal energy offers a sustainable and low-carbon pathway to meet rising global energy demands, particularly in tectonically active regions such as Pinrang Regency, South Sulawesi, Indonesia. This study presents the first integrated geochemical and geoelectrical characterization of the Lemosusu and Sulili hot springs to evaluate their geothermal potential. Field measurements show surface temperatures between 41 and 46 °C. Geochemical classification using Cl–SO₄–HCO₃ diagrams and silica/Na–K geothermometry indicates that Lemosusu hosts a shallow, bicarbonate-dominated low-enthalpy system (44–77 °C), whereas Sulili contains chloride-rich fluids with reservoir temperatures up to 178 °C, reflecting a more evolved hydrothermal regime. Two-dimensional resistivity imaging reveals distinct subsurface signatures: Lemosusu is characterized by a shallow conductive layer (<5 Ωm) overlying volcaniclastics of the Loka Formation at depths of 10–15 meters, suggesting fluid circulation within porous horizons. In contrast, Sulili displays a vertically continuous conductive zone (<5 Ωm) extending to depths 13 m, coinciding with a mapped fault zone interpreted as a potential main upflow pathway. These findings demonstrate that Lemosusu appears suitable for small-scale direct-use applications such as balneotherapy and greenhouse heating, while Sulili holds potential for binary-cycle power generation. Overall, the integration of geochemical and geoelectrical data provides new insight into how lithologic porosity and fault structures jointly control geothermal fluid flow in mixed volcanic–sedimentary terrains, offering a replicable framework for exploration in under-explored geothermal provinces worldwide.

地热能为满足不断增长的全球能源需求提供了可持续和低碳的途径，特别是在印度尼西亚南苏拉威西岛平朗摄政等构造活跃地区。本文首次对Lemosusu和Sulili温泉进行了地球化学和地电综合表征，以评价其地热潜力。现场测量显示表面温度在41至46°C之间。利用Cl-SO₄-HCO₃图解和silica/ Na-K地热方法进行地球化学分类表明，Lemosusu为浅层碳酸盐岩为主的低焓体系（44 ~ 77℃），而Sulili为富氯化物流体，储层温度高达178℃，反映了更为演化的热液体系。二维电阻率成像显示了明显的地下特征：Lemosusu的特征是在10-15米深的Loka组火山碎屑上覆盖了一层浅层导电层（<5 Ωm），表明孔隙层内存在流体循环。相比之下，Sulili显示出一个垂直连续的导电带（<5 Ωm），延伸至深度13 m，与被解释为潜在主要上行通道的地图断裂带相吻合。这些发现表明，Lemosusu似乎适合小规模的直接使用应用，如水疗和温室加热，而Sulili具有双循环发电的潜力。总体而言，地球化学和地电数据的整合为火山-沉积混合地形中岩性孔隙度和断裂构造如何共同控制地热流体流动提供了新的视角，为全球地热勘探不足地区的勘探提供了可复制的框架。

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引用次数: 0

Geothermal potential of karstified Devonian carbonates in NW Germany 德国西北部泥盆纪碳酸盐岩岩溶的地热潜力

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2025-12-08 DOI: 10.1016/j.geothermics.2025.103552

Manfred Heinelt , Mathias Mueller , Benedikt Ahrens , Mathias Nehler , Katharina Alms , Adrian Immenhauser

The exploration of suitable reservoir rocks for deep geothermal energy in NW Germany focuses on karstified carbonates of Carboniferous and Devonian age. Using a case example from the city of Iserlohn, we demonstrate that these rocks exhibit high thermal yields due to the secondary porosity caused by meteoric (and potentially hypogenic) karstification. Karstified carbonates, if structurally interconnected on a reservoir scale, have the potential to provide significantly higher permeability. We conducted thermo-triaxial cell experiments for depths exceeding 2 km. Our findings indicate that dolostones offer enhanced mechanical integrity and exhibit reduced porosity loss with increasing depth. Visual inspections of µCT scans confirm that karstification results in large, interconnected pores that have been leached. The effective porosity of karstified carbonates reaches 14 %, with measured permeability values in the order of 10⁻¹⁶ m². In terms of porosity and permeability, karstified units can outperform non-karstified ones by up to two orders of magnitude. We conducted heat-in-place modelling using petrophysical laboratory data as input parameters for Monte Carlo simulations. An initial map was created to illustrate the potential geothermal energy stored and to identify areas with the highest energy yield. The estimated potential energy stored in the subsurface is greatest in the southern part of the Iserlohn study area, where the thickness of the Devonian carbonates is at its maximum. This deeper occurrence in the subsurface leads to a significant increase in reservoir temperature. The modelling results indicate a potential energy range for the entire distribution of Devonian carbonates between 87 TJ (P90) and 110 TJ (P10).

德国西北部适合深层地热能的储层主要以石炭系和泥盆系岩溶碳酸盐岩为主。以Iserlohn市为例，我们证明了这些岩石由于大气（和潜在的低成因）岩溶作用引起的次生孔隙而表现出高热产量。如果岩溶盐岩在储层规模上相互连接，则具有显著提高渗透率的潜力。我们进行了深度超过2公里的热三轴电池实验。我们的研究结果表明，随着深度的增加，白云岩的机械完整性增强，孔隙度损失减少。微CT扫描的目视检查证实，岩溶作用导致浸出的大而相互连接的孔隙。碳酸盐岩的有效孔隙度达14%，实测渗透率为10 ~ 16 m²。在孔隙度和渗透率方面，岩溶单元可以比非岩溶单元高出两个数量级。我们使用岩石物理实验室数据作为蒙特卡罗模拟的输入参数，进行了就地热模拟。初步绘制了一张地图，以说明潜在的地热能储存，并确定能源产量最高的地区。Iserlohn研究区南部泥盆纪碳酸盐岩厚度最大，估算的地下储存势能最大。地下较深的分布导致储层温度显著升高。模拟结果表明，整个泥盆纪碳酸盐岩分布的势能范围在87 TJ (P90) ~ 110 TJ （P10）之间。

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引用次数: 0

Classification of closed-loop GCHP suitability via governing mechanism of hydrogeological attributes: Case Research in Karstic Terrain, Guiyang, China 基于水文地质属性控制机制的闭环GCHP适宜性分类——以贵阳岩溶地形为例

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2025-12-04 DOI: 10.1016/j.geothermics.2025.103547

Yi Liu , Peng Pei , Xiaolin Tian

The suitability of closed-loop ground-coupled heat pump (GCHP) was evaluated and classified in the urban area of Guiyang, China, a typical karstic terrain with complex hydrogeological conditions in pure carbonate rocks, interbedded carbonate-clastic rocks, and fissures. The classification task investigated and emphasized the controlling mechanism of site-specified spatial variation and seasonal fluctuation of groundwater flow on borehole heat transfer ability, ground thermal properties and recoverability from thermal imbalance. Within an area of 2525.4 km², it delineated 9 abundant resource areas (16.2 % of the total area), 8 moderate resource areas (53.2 %), and 7 limited resource areas (30.6 %). The framework is adaptable to other regions for zoning and planning shallow geothermal energy exploitation. Successful application requires regional geological structural and hydrogeological information as input, and users’ expertise to identify water conduits and aquifers, and professional judgment regarding the relative advantages of hydrogeological and thermal conditions in a given area. The framework can provide more scientifically round and accurate guide for suitability zoning, permitting and allocation of shallow geothermal energy resources in complex hydrogeological settings.

在纯碳酸盐岩、碳酸盐岩-碎屑岩互层、裂隙发育、水文地质条件复杂的典型岩溶地形中，对闭环地耦合热泵（GCHP）的适宜性进行评价和分类。该分类任务研究并强调了地表水流量的定点空间变化和季节波动对钻孔换热能力、地表水热物性和热平衡恢复能力的控制机制。在2525.4 km2范围内，圈定了资源丰富区9个（占总面积的16.2%），资源中等区8个（占总面积的53.2%），资源有限区7个（占总面积的30.6%）。该框架适用于其他地区浅层地热能开发分区和规划。成功的应用需要区域地质构造和水文地质信息作为输入，以及用户识别水管和含水层的专业知识，以及对特定地区水文地质和热条件相对优势的专业判断。该框架可为复杂水文地质环境下浅层地热能资源适宜性区划、许可和配置提供更为科学、全面和准确的指导。

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引用次数: 0

Real scale evaluation of geothermal heat exchanger performances integrated to poultry house 禽舍一体化地热换热器性能的实际规模评价

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2025-12-03 DOI: 10.1016/j.geothermics.2025.103553

Oussama Zobiri , Abdelmalek Atia , Müslüm Arıcı

There is a growing body of literature that recognizes the importance of Heating, Ventilation and Air Conditioning systems (HVAC) based on ground to air heat exchangers (GAHEs). In the present experimental work, real field experimental setup of GAHEs to study the air quality of GAHE outlet inside a poultry house compared with air ambient and the conventional poultry house (CPH). Results showed that mean air temperature of heat exchanger at the outlet is stable, which remains closer than 24.2 °C, and the average GAHE efficiency is reached 92 % during the experiment period. GAHE maintains an average relative humidity of around 32 % due to the movement and rotation of air stream caused by the fan. GAHE plays a positive role in the ventilation process of the poultry house, as it renews the amount of air inside the poultry room during the study period. One of the more significant findings to emerge from this study is that the Carbon dioxide (CO₂) concentration inside the poultry house integrated with geothermal heat exchangers is less than the concentration that exists in conventional one by 400 parts per million (ppm). The application of geothermal energy systems in buildings holds great potential due to its availability, being considered naturally free and sustainability contributions.

越来越多的文献认识到基于地对空热交换器（GAHEs）的采暖、通风和空调系统（HVAC）的重要性。在本实验工作中，通过对GAHE的现场实验设置，比较了GAHE出风口与环境空气和传统禽舍（CPH）的空气质量。结果表明，换热器出口平均空气温度稳定，保持在24.2℃以下，实验期间GAHE平均效率达到92%。由于风扇引起的气流的运动和旋转，GAHE保持大约32%的平均相对湿度。GAHE在家禽舍通风过程中发挥了积极的作用，因为它在研究期间更新了家禽舍内的空气量。从这项研究中得出的一个更重要的发现是，安装了地热热交换器的鸡舍内的二氧化碳浓度比传统鸡舍内的二氧化碳浓度低400 ppm。地热能系统在建筑物中的应用具有巨大的潜力，因为它的可用性，被认为是自然免费和可持续的贡献。

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引用次数: 0

Geothermal resources pathways: the hydrochemical evolution and genesis of geothermal waters in the Xianshuihe fault Zone, eastern Qinghai-Xizang plateau 地热资源途径：青藏高原东部鲜水河断裂带地热水的水化学演化与成因

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2025-12-03 DOI: 10.1016/j.geothermics.2025.103551

Yunhui Zhang , Jinhang Huang , Xingze Li , M. Santosh , Ying Wang , Xingcheng Yuan , Yangshuang Wang , Hongyang Guo , Xiaoyan Zhao , Xun Huang

Exploiting and utilizing geothermal resources require a clear understanding of their genesis mechanisms. Regional fault zones often host abundant geothermal resources whose genesis connections are not well understood. This study aims to elucidate the hydrochemical properties and formation mechanisms of diverse geothermal systems within the Xianshuihe Fault Zone (XFZ), eastern Qinghai-Xizang Plateau. The Self-Organizing Maps and Positive Matrix Factorization algorithms, hydrochemical analysis, and hydrogen-oxygen isotope analysis were employed to identify the intrinsic genesis connections among different types of geothermal waters in the XFZ. The geothermal waters along the XFZ were classified into three groups (Groups 1 − 3). Group 1 is predominantly Cl-Na and Cl·HCO₃-Na types; Group 2 is of HCO₃-Na and SO₄·HCO₃-Na types; and Group 3 primarily belongs to HCO₃-Na and HCO₃-Ca types. The primary source of geothermal water in Groups 1–3 is from fluids stored in deep granitic reservoirs, accounting for 40.1%, 28.8%, and 25.0% in each respective group. The secondary source is the infiltrating cold water leaching the shallow sedimentary rock, contributing 33.5%, 23.6%, and 25.7%, respectively. The primary sources of recharge for the geothermal water in the study area are snow-melting and meteoric water. Group 1 exhibits the highest reservoir temperatures (124.5 °C to 224.1 °C), followed by Group 2 (93.6 °C to 191.7 °C), and Group 3 (75.1 °C to 164.2 °C). This study indicates that the spatial distribution of geothermal water from Group 1 ('Deep Initial Geothermal Water') to Group 2 ('Evolved Shallow Geothermal Water') and Group 3 ('Mixed Shallow Geothermal Water') is a common phenomenon along the XFZ. Based on these findings, this study establishes a conceptual model for different groups of geothermal waters, which also helps establish interconnections among geothermal systems in regional fault zones.

地热资源的开发利用需要对其成因机制有清晰的认识。区域性断裂带往往蕴藏着丰富的地热资源，其成因联系尚不清楚。本研究旨在阐明青藏高原东部鲜水河断裂带不同地热系统的水化学性质及其形成机制。利用自组织图（Self-Organizing Maps）和正矩阵分解（Positive Matrix Factorization）算法、水化学分析和氢氧同位素分析等方法，确定了XFZ不同类型地热水的内在成因联系。沿XFZ的地热水可划分为3类（1 ~ 3类）。第1组以Cl- na型和Cl·HCO3-Na型为主；第2组为HCO3-Na型和SO4·HCO3-Na型；第3族主要属于HCO3-Na型和HCO3-Ca型。1 ~ 3组地热水的主要来源为深部花岗质储层流体，占比分别为40.1%、28.8%和25.0%。次源为浅层沉积岩的渗透冷水淋滤，贡献率分别为33.5%、23.6%和25.7%。研究区地热水补给的主要来源是融雪和大气降水。组1表现出最高的储层温度（124.5°C至224.1°C），其次是组2（93.6°C至191.7°C）和组3（75.1°C至164.2°C）。研究表明，从第1组（“深层初始地热水”）到第2组（“演化浅层地热水”）和第3组（“混合浅层地热水”）地热水的空间分布是XFZ沿线普遍存在的现象。在此基础上，本研究建立了不同组地热水的概念模型，有助于建立区域断裂带地热系统之间的相互联系。

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引用次数: 0

Mechanisms underlying sulfate concentration variations in geothermal waters around the Wugongshan area 武公山地区地热水硫酸盐浓度变化机制

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2025-12-02 DOI: 10.1016/j.geothermics.2025.103550

Li Gong , Zheming Shi , Ximin Bai , Yunfei Bai , Jue Tong , Bangmin Li

Understanding the sources of sulfate in geothermal waters is crucial for elucidating hydrothermal cycling mechanisms and the pathways of sulfur transport and transformation within hydrothermal systems. Distinct SO₄^2– concentrations have been observed in the eastern and western sections of the Wugongshan hydrothermal system; however, the origins and mechanisms of these variations remain unexplored. In this study, a combined hydrogeochemical and microbial analysis was conducted on 11 samples collected from geothermal wells across the Wugongshan geothermal field. The results indicated that silicate weathering, particularly feldspar dissolution influenced by CO₂, was the dominant geochemical process in Wugongshan’s geothermal waters. The western samples (XQ and ZK08) exhibited minimal cold-water dilution during ascent, preserving distinct hydrogeochemical signatures. Eight types of sulfur-oxidizing genes were identified, with XQ and ZK08 showing the highest abundances. Strong correlations existed between microbial taxa (e.g., Thiovirga, Thiobacillus in XQ; Tepidimonas, Meiothermus in ZK08), functional genes (fccAB, dsrABC, sox clusters), and SO₄^2– production. Microbial metabolic pathways were the primary drivers of SO₄^2– variation across the region. In the eastern Wugongshan samples, SO₄^2– was sourced exclusively from gypsum dissolution, whereas in the west, microbially mediated sulfide oxidation (e.g., pyrite and H₂S) dominated SO₄^2– generation. This study aims to delineate the mechanisms behind sulfate concentration variations in geothermal waters of the Wugongshan area, with particular focus on microbial and mineralogical contributions.

了解地热水中硫酸盐的来源对于阐明热液循环机制和热液系统中硫的转运转化途径至关重要。武公山热液系统东段和西段SO42 -浓度明显不同；然而，这些变异的起源和机制仍未被探索。本研究对武公山地热田11口地热井样品进行了水文地球化学和微生物联合分析。结果表明，在CO2的作用下，硅酸盐风化作用，尤其是长石溶蚀作用是武公山地热水的主要地球化学过程。西部样品（XQ和ZK08）在上升过程中表现出最小的冷水稀释，保留了明显的水文地球化学特征。共鉴定出8种硫氧化基因，其中XQ和ZK08的丰度最高。微生物分类群（如XQ中的thiiovirga、Thiobacillus； ZK08中的Tepidimonas、Meiothermus）、功能基因（fccAB、dsrABC、sox簇）和SO42 -产量之间存在很强的相关性。微生物代谢途径是该地区SO42 -变化的主要驱动因素。在武公山东部样品中，SO42 -主要来自石膏溶解，而在西部样品中，微生物介导的硫化物氧化（如黄铁矿和H2S）主要是SO42 -的生成。本研究旨在探讨武公山地区地热水中硫酸盐浓度变化的机制，重点探讨微生物和矿物学的贡献。

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引用次数: 0

Investigation of particle transport in geothermal systems using integrated CFD–DEM and data-driven approaches 基于CFD-DEM和数据驱动方法的地热系统粒子输运研究

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2025-12-01 DOI: 10.1016/j.geothermics.2025.103533

Younes Tatari , Hoai Thanh Nguyen , Amirhossein Arzani , Pania Newell

Geothermal systems provide continuous, low-carbon energy by harnessing the Earth’s renewable heat, but their efficiency can be hindered by issues such as limited heat production and thermal breakthrough. A promising approach to overcome these issues is to inject polymer-based microcapsules into fractures to modify permeability, which requires a clear understanding of particle transport within the fracture network. To do so, this study used Computational Fluid Dynamics–Discrete Element Method (CFD–DEM) simulations combined with machine learning (ML) to capture particle transport behavior under varying temperature conditions. The dataset comprises 45 CFD–DEM test cases, which are generated by coupling OpenFOAM (for fluid dynamics) and LIGGGHTS (for particle tracking), enabling detailed modeling of thermo-hydro processes and particle interactions. To assess their influence on transport behavior, key parameters include particle diameter (

D

), formation temperature (

T

), and particle volume fraction (

ϕ

). Supervised learning models, including random forest and interpretable decision tree classifiers, were trained to classify flow blockage. Feature importance analysis identified

ϕ

and

D

as the most critical factors impacting the particle transports. To avoid sealing progression, the accumulation of low-velocity particles over time was fit with a sigmoid function. Results show that higher particle concentrations and larger diameters reduce transport efficiency, while elevated inlet velocities enhance particle mobility and prolong transport through the fracture. This interpretable data-driven approach, grounded in CFDEM simulations, offers a predictive tool for particle transport in fractures subject to complex geothermal environments.

地热系统通过利用地球的可再生热量提供持续的低碳能源，但其效率可能受到诸如有限的产热和热突破等问题的阻碍。克服这些问题的一种很有希望的方法是将聚合物微胶囊注入裂缝中以改变渗透率，这需要清楚地了解裂缝网络中的颗粒传输。为此，本研究使用计算流体动力学-离散元方法（CFD-DEM）模拟结合机器学习（ML）来捕获不同温度条件下的粒子输运行为。该数据集包括45个CFD-DEM测试用例，这些测试用例是通过耦合OpenFOAM（用于流体动力学）和lights（用于颗粒跟踪）生成的，可以对热水力过程和颗粒相互作用进行详细建模。为了评估它们对输运行为的影响，关键参数包括颗粒直径(D)、地层温度(T)和颗粒体积分数（ϕ）。包括随机森林和可解释决策树分类器在内的监督学习模型被训练用于对流量阻塞进行分类。特征重要性分析确定了ϕ和D是影响粒子输运的最关键因素。为了避免密封进程，低速粒子随时间的累积用s型函数拟合。结果表明，较高的颗粒浓度和较大的颗粒直径降低了颗粒的输运效率，而较高的入口速度提高了颗粒的迁移率，延长了颗粒通过裂缝的输运时间。这种基于CFDEM模拟的可解释数据驱动方法，为复杂地热环境下裂缝中的颗粒运移提供了预测工具。

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引用次数: 0

Study on the heat transfer performance of deep buried pipe energy pile with phase change backfill materials 相变充填材料深埋管道能源桩传热性能研究

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2025-11-27 DOI: 10.1016/j.geothermics.2025.103539

Jingqi Huang , Zhi Chen , Henglin Xiao , Huanzhen Xie , Bin Yu

This research comprehensively investigates how shape-stabilized phase change materials (SSPCM), when used as backfill, influence the thermal performance of deep buried pipe energy pile (DBP-EP). By integrating field experimental data with numerical simulations, a comparative analysis is conducted between conventional grout and three SSPCM variants. The investigation focuses on how latent heat, thermal conductivity, and phase change temperature affect the performance of the system under intermittent operation. The findings reveal that SSPCM backfill significantly improves the initial heat exchange capacity and overall energy efficiency of DBP-EP, while also reducing the thermal influence zone—though these benefits tend to diminish over extended operation. Under summer conditions, SSPCM enhances early-stage heat extraction in the heat exchange well and effectively cools the pile shaft. Specifically, utilizing the latent heat and thermal conductivity, as well as reducing the phase-change temperature (in cooling mode), all of which contribute to the optimization of the heat transfer efficiency, energy efficiency ratio (EER), and thermal radius. Under intermittent operating conditions, the application of SSPCM materials significantly reduces outlet water temperature compared to conventional grouting materials, with a more substantial enhancement in heat transfer capacity relative to continuous operation modes; however, the heat exchange efficiency of the system demonstrates a decreasing trend as the intermittent ratio increases. Among tested scenarios, an 8 h on/16 h off mode offers the best performance. This study offers new insights into the role of SSPCM in enhancing thermal performance under intermittent operation, providing valuable guidance for material selection and operation strategies in energy pile systems.

本文全面研究了形状稳定相变材料（SSPCM）作为回填体对深埋管道能源桩（DBP-EP）热性能的影响。通过现场试验数据与数值模拟相结合，对常规注浆与三种SSPCM型注浆进行了对比分析。研究的重点是潜热、导热系数和相变温度对间歇运行下系统性能的影响。研究结果表明，SSPCM回填显著提高了DBP-EP的初始热交换能力和整体能源效率，同时也减小了热影响区，尽管这些好处随着运行时间的延长而逐渐减少。在夏季条件下，SSPCM增强了换热井的早期抽热，有效地冷却了桩身。具体来说，利用潜热和导热系数，以及降低相变温度（在冷却模式下），这些都有助于优化传热效率、能效比（EER）和热半径。在间歇运行工况下，与常规注浆材料相比，SSPCM材料的应用显著降低了出水温度，相对于连续运行模式，其换热能力的增强更为显著；但随着间歇比的增大，系统的换热效率呈下降趋势。在测试场景中，8小时开/16小时关模式提供了最佳性能。该研究对SSPCM在间歇运行条件下提高热性能的作用提供了新的见解，为能源桩系统的材料选择和运行策略提供了有价值的指导。

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引用次数: 0