Geothermics最新文献

{"title":"Study on low thermal conductivity cement reinforced by sepiolite fiber for deep geothermal well","authors":"Shuai Liu ,&nbsp;Chunmei Zhang ,&nbsp;Chen Hu ,&nbsp;KaiYuan Mei ,&nbsp;Xiaowei Cheng","doi":"10.1016/j.geothermics.2025.103290","DOIUrl":"10.1016/j.geothermics.2025.103290","url":null,"abstract":"<div><div>To address the significant heat loss in the thermal insulation layer of geothermal wells and the failure of the cement sheath, expanded perlite (EP), hollow glass microspheres (HGM), and SiO₂ aerogel (SA) were integrated into oil well cement slurry to achieve optimal low thermal conductivity. Hydrothermal-acid-treated sepiolite fibers (T-SEP) were utilized to enhance the mechanical properties of oil well cement paste with low thermal conductivity, and the strengthening process was examined. The findings indicate that the inclusion of EP, HGM, and SA diminishes the thermal conductivity and compressive strength of cement paste. The integration of T-SEP markedly improved the compressive strength of cement paste with low thermal conductivity at elevated temperatures, with a 73.88 % enhancement seen in the cement paste cured at 180 °C for 7 days compared to pure cement paste. The inclusion of T-SEP decreased the reduction rate of compressive strength in cement paste subjected to thermal cycling. In contrast to the 24.14 % reduction in compressive strength of pure cement paste after the fifth thermal cycle, the compressive strength loss of cement paste with T-SEP is merely 12.5 %. The microstructure test indicates that the addition of T-SEP at elevated temperatures enhances the development of cement hydration products, including C-S-H, C₅S₆H₅, and C₆S₂H₃, hence improving the mechanical properties of cement paste with low thermal conductivity. An effective interface is established between T-SEP and cement paste, enhancing the compressive strength and thermal shock resistance of cement paste with low thermal conductivity.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"129 ","pages":"Article 103290"},"PeriodicalIF":3.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143520581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Data-driven prediction of long-term thermal performance for steel pipe heat exchanger (SPHX) energy piles","authors":"Seokjae Lee ,&nbsp;Dongku Kim ,&nbsp;Hyeontae Park ,&nbsp;Hangseok Choi ,&nbsp;Sangwoo Park","doi":"10.1016/j.geothermics.2025.103292","DOIUrl":"10.1016/j.geothermics.2025.103292","url":null,"abstract":"<div><div>Determining the thermal performance of ground heat exchangers (GHEXs) remains a critical challenge in the design of ground source heat pump (GSHP) systems. Among various GHEX types, the steel pipe heat exchanger (SPHX) energy pile is an innovative solution that utilizes steel pipes as both the primary reinforcement and heat exchangers, replacing conventional deformed rebars. However, its practical implementation has been hindered by the absence of a reliable method for predicting its thermal performance. In this study, an artificial neural network (ANN)-based prediction model was developed to estimate the thermal performance of SPHX energy piles. A computational fluid dynamics (CFD) model was formulated using in-situ thermal performance test (TPT) results, and a numerical database was established by considering various influential factors, such as the thermal conductivity of concrete and ground formations, the flow rate of the working fluid, and the initial temperature of the ground formations. These datasets were utilized to train the ANN model. The developed ANN model exhibited high accuracy in predicting the average heat exchange amount of SPHX energy piles, with an average error of 1.53 %. Furthermore, the model enabled the evaluation of the long-term thermal performance of SPHX energy piles based on the observed linear correlation between the average heat exchange amount and the operation time.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"129 ","pages":"Article 103292"},"PeriodicalIF":3.5,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing Seferihisar-İzmir (Türkiye) geothermal energy prospects through marine seismic and field geology data modelling","authors":"Gizem Kılınç ,&nbsp;Günay Çifci ,&nbsp;Seda Okay Günaydın ,&nbsp;Altuğ Hasözbek ,&nbsp;Savaş Gürçay ,&nbsp;Talip Güngör ,&nbsp;Zülfü Demirkıran ,&nbsp;Melih Çobanoğlu","doi":"10.1016/j.geothermics.2025.103295","DOIUrl":"10.1016/j.geothermics.2025.103295","url":null,"abstract":"<div><div>Seferihisar (Izmir) is one of the most significant geothermal regions in the Aegean of Western Anatolia, Türkiye, due to its high geothermal gradient, extensive fault systems, and unique interaction between marine and meteoric waters that create distinct geothermal reservoirs. This study evaluates the geothermal potential and geological characteristics of the Seferihisar area by integrating marine seismic data with onshore geological observations. Specifically, this study combines: (i) geological and geochemical data from geothermal wells along the Tuzla Fault, (ii) high-resolution multichannel seismic reflection data from the Sigacik and Kusadasi Bays, and (iii) correlated onshore and offshore geological and geophysical datasets to develop a 2D conceptual cross-section and a 3D fault model.</div><div>Geochemical analyses, including water geochemistry, XRF, and isotope studies, reveal that geothermal fluids in the region originate from a mix of meteoric and marine sources. Chloride concentrations in geothermal wells reach approximately ranging from 11,692 to 12,000 ppm, confirming significant seawater intrusion, while geothermometers estimate reservoir temperatures in the range of 220–280 °C. Isotopic data, such as ³He/⁴He ratios (∼0.9 Ra), suggest minor mantle involvement, and ⁴⁰Ar/³⁶Ar ratios ranging 301 that indicate crustal contributions to the geothermal fluids. These isotopic signatures provide critical insights into the sources and circulation dynamics of geothermal systems.</div><div>Through integrated 2D conceptual cross-sections and 3D fault modeling, the study identifies the marine extension of the Tuzla Fault and its role in fluid dynamics, including up-flow and out-flow processes. The fault's continuities are linked to geothermal gradients and active fluid pathways, making the Tuzla Fault a critical target for geothermal exploration. The harmonized models suggest three potential drilling sites with high thermal gradients and fault-controlled fluid flow, optimizing the exploration strategy. Scaling and corrosion challenges in production wells are addressed through the application of inhibitors, which are integral to ensuring sustainable operation and long-term system performance.</div><div>These multidisciplinary findings provide likely actionable insights into optimizing resource extraction, reducing environmental impact, and improving the long-term performance of geothermal systems. The study supports sustainable geothermal energy development in the Seferihisar region by addressing production challenges and guiding effective resource management.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"129 ","pages":"Article 103295"},"PeriodicalIF":3.5,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of evaluation models for geothermal resources and intermittent operation/cycle thermal storage mode in closed coal mines","authors":"Meng Wang ,&nbsp;Pingye Guo ,&nbsp;Cheng Fang ,&nbsp;Mohua Bu ,&nbsp;Xin Jin ,&nbsp;Jiong Wang","doi":"10.1016/j.geothermics.2025.103294","DOIUrl":"10.1016/j.geothermics.2025.103294","url":null,"abstract":"<div><div>The geothermal utilization of closed mines has a positive role to play in the reduction of fossil energy consumption, the development of renewable energy sources and the proper disposal of closed mine. In this work, for a more accurate evaluation of the sustainable geothermal production in closed mine, based on Xuzhou Jiahe coal mine, a 3D numerical model coupling roadway and goaf is established, and compared with other two numerical models. After analyzing the water storage space, flow field, temperature field, recovery well outlet temperature and heat recovery stability under long operation time, the roadway and goaf (RG) model performs more prominently and the results are more realistic. Both intermittent operation and cycle thermal storage mode have a higher recovery well outlet temperature in winter operation period, it can keep the heat supply at a high level, and accordingly the operational life of closed mine geothermal utilization system can be extended. COP (Coefficient of performance) of the system in winter operation period with different operation modes are basically the same when the recovery flow rate is low. As the recovery flow rate increase, COP of the system in cycle thermal storage mode has a significant advantage. In summer operation period, the outlet temperature in thermal storage cycle mode remains lower than the recharged hot water temperature, and it has a good cooling effect under high recovery flow conditions in the summer, contributes to the temperature return of thermal reservoir, and COP of the system in summer operation increase with recovery flow rate.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"129 ","pages":"Article 103294"},"PeriodicalIF":3.5,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143488332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical analysis of heat transfer performance in medium-depth coaxial casing heat exchangers considering seepage effects","authors":"Ye Wang ,&nbsp;Pan Yue ,&nbsp;Luyu Zhang ,&nbsp;Wenyu Dang","doi":"10.1016/j.geothermics.2025.103293","DOIUrl":"10.1016/j.geothermics.2025.103293","url":null,"abstract":"<div><div>This study presents an innovative analytical model for a 3000-meter-deep coaxial borehole heat exchanger (CBHE) that simultaneously considers geothermal gradients, geological stratification, groundwater seepage, and the vertical permeability of the seepage layer. By focusing on the annular fluid and its temperature response within the borehole layer, the model incorporates factors often neglected in previous research, including the influence of groundwater flow and the thermal property variations across different soil and rock layers. The results show that seepage significantly enhances heat transfer via distinct mechanisms. For instance, when the seepage layer is located at a depth of 2000 m, conduction-dominated heat exchange is critical at a seepage velocity of 5 × 10⁻⁷ m/s, whereas exceeding 1 × 10⁻⁵ m/s shifts the dominant mechanism to convective heat transfer, thereby increasing the local heat exchange intensity in the annular fluid by 56.7 %. Furthermore, optimizing the inner pipe's insulation length significantly enhances system efficiency by increasing the outlet temperature and reducing thermal losses. The study also establishes a relationship between seepage parameters and the necessary buried depth for achieving a given heat extraction. These findings offer valuable theoretical guidance for improving geothermal system performance and hold significant engineering implications for sustainable geothermal energy utilization.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"129 ","pages":"Article 103293"},"PeriodicalIF":3.5,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143510523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new approach to building 2-D models of the heat flow density and radiogenic heat production: A Northern Tien Shan case study","authors":"Viacheslav V. Spichak,&nbsp;Alexandra G. Goidina","doi":"10.1016/j.geothermics.2025.103289","DOIUrl":"10.1016/j.geothermics.2025.103289","url":null,"abstract":"<div><div>We propose a new approach to building 2-D / 3-D models of the regional HFD from the ground geophysical data without prior knowledge of the radiogenic heat production (RHP). A vertical heat flow density (HFD) vector map built for the study area enabled us to distinguish different heat sources in the crust, particularly, cooling of solidified felsic magma upwelling from the mantle depth, and radiogenic heat production in granitoids. An approach to assessing the apparent regional HFD is suggested. It uses the thermal conductivity and temperature models determined from the electromagnetic sounding data and borehole measurements. Numerical experiments show that when it is estimated for the layers with a thickness ranging from 1 to 5 km (which is similar to the surface HFD assessment from borehole measurements), the relative misfits can reach 30–80 %. On the other hand, it becomes practically insensitive to the thickness of the virtual layer approaching its value for the whole section (with uncertainty less than 10 %) when its lower depth exceeds some threshold level, in particular, exceeding the effective depth of the RHP decay in the study area. An approach to building 2-D model of the RHP rates from the lithology model and their values determined at the surface is proposed. It offers a more realistic surface RHP assessment than estimates based on constant RHP rates determined at the surface. It is shown that effective surface RHP is affected mainly by granitic rocks’ spatial distribution and could be a main heat source in the upper crust.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"129 ","pages":"Article 103289"},"PeriodicalIF":3.5,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143479819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sampling and analysis of H2S and Hg from evaporative geothermal cooling towers: The Italian experience","authors":"Alessandro Lenzi ,&nbsp;Marco Paci ,&nbsp;Alessandro Bettini ,&nbsp;Antonio Caprai ,&nbsp;Alessandro D'Ulivo ,&nbsp;Massimo Onor ,&nbsp;Marco Carlo Mascherpa ,&nbsp;Beatrice Campanella","doi":"10.1016/j.geothermics.2025.103291","DOIUrl":"10.1016/j.geothermics.2025.103291","url":null,"abstract":"<div><div>The Italian regulatory framework on geothermal power plants requires measurement of the emission of H₂S and Hg from cooling towers. Sampling of emitted air in geothermal plants is a quite complex task requiring specific non-standard methods in order to collect stable and representative samples. A direct application of standard methods for H₂S and Hg emissions to cooling tower is often not suitable or difficult to apply. The standard methods indeed were developed for sampling in the stacks of combustion plants such as power generation or cement production plants. The drastic difference in temperature, humidity, air flow composition and velocity and moreover geometrical difference between stacks with diameters of few meters compared to cells of cooling towers, very often over 5–9 m, required a special setup of methods for sampling and analysis. Enel Green Power and Consiglio Nazionale delle Ricerche (Italy) thus have carried out a screening of the existing methods and some of them were customized and extended for their application on cooling towers of geothermal power plants. The main results obtained provided suitable sampling and analysis methods for H₂S in the range 0.2–25 mg/Nm³ and for mercury between 20–500 µg/Nm³. The aforementioned sampling and analysis methods are currently adopted by EGP and by the regional agency for environmental protection (ARPAT) for the measurement of H₂S and Hg emission from cooling towers of geothermal power plants in Italy.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"129 ","pages":"Article 103291"},"PeriodicalIF":3.5,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reservoir thermal energy storage pre-assessment for the United States","authors":"Jeff D. Pepin ,&nbsp;Erick R. Burns ,&nbsp;Ryan C. Cahalan ,&nbsp;Daniel O. Hayba ,&nbsp;Jesse E. Dickinson ,&nbsp;Leslie L. Duncan ,&nbsp;Eve L. Kuniansky","doi":"10.1016/j.geothermics.2025.103256","DOIUrl":"10.1016/j.geothermics.2025.103256","url":null,"abstract":"<div><div>Storing thermal energy underground for later use in electricity production or direct-use heating/cooling is a promising, viable, and economical green energy option. Reservoir thermal energy storage (RTES) is one such option, which stores energy in underutilized permeable strata with low ambient groundwater flow rates and more geochemically evolved (e.g. brackish/saline) waters relative to overlying principal aquifer systems. The U.S. Geological Survey has begun assessing RTES potential nationally by focusing on five generalized geologic regions (Basin and Range, Coastal Plain, Illinois Basin, Michigan Basin, Pacific Northwest) across the United States. Hydrogeologic reservoir models are developed for the following eight metropolitan area cities within those regions to evaluate RTES performance across different climates and subsurface conditions: Albuquerque, New Mexico; Charleston, South Carolina; Chicago and Decatur, Illinois; Lansing, Michigan; Memphis, Tennessee; Phoenix, Arizona; and Portland, Oregon. Evaluated metrics include estimated required well spacing, thermal storage capacity, and thermal recovery efficiency through time. Also considered for each reservoir are potential complicating factors, including reservoir depth, thermally driven free convection, and groundwater salinity. This work focuses on direct-use cooling because the need for cooling modern office buildings greatly exceeds that for heating in most parts of the country (Falta and others, 2016); however, the evaluated metrics are also relevant to heating and electricity applications. Results indicate that favorable RTES conditions exist in each region, with the Coastal Plain and Basin and Range being especially favorable for thermal storage capacity, whereas the Pacific Northwest and Michigan Basin excel at energy recovery for the evaluated cooling application. The results underscore the utility of developing maps of thermal storage capacity, subsurface temperature models, and volumetric estimates of thermal storage capacity to serve as key RTES resource classification standards. Overall, this pre-assessment provides a basic understanding of RTES potential in several cities and geologic regions throughout the country and could aid ongoing thermal energy storage assessment efforts.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"129 ","pages":"Article 103256"},"PeriodicalIF":3.5,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143464322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prospects and challenges for utilisation of low- to medium-temperature geothermal resources in Tanzania","authors":"Neema Bernad Mjami ,&nbsp;Cuthbert Kimambo ,&nbsp;Sarah Ayeng'o ,&nbsp;Ivanka Orozova-Bekkevold","doi":"10.1016/j.geothermics.2025.103288","DOIUrl":"10.1016/j.geothermics.2025.103288","url":null,"abstract":"<div><div>The key purpose of this qualitative study is to explore the potential for effective utilisation of low- to medium-temperature (i.e., ˂150 °C) geothermal resources in Tanzania. Worldwide, these resources are mostly harnessed locally for direct use as a heat source. In contrast, high-temperature resources are mainly used for power generation, becoming an important component of the national energy supply. As a result, the development of the latter is more advanced than that of the former. In Tanzania, five geothermal resources have been chosen as priority areas for development. Three of them, Luhoi, Songwe, and Kiejombaka, are low- to medium-temperature resources, while the other two, Ngozi and Natron, are most likely to host both low- to medium and high-temperature systems. However, the progress is slow due to funding scarcity, insufficient knowledge of the geothermal systems, and a lack of understanding of how they can be effectively utilised to enhance economic development in the local communities. In investigating the most suitable methods for utilising low- to medium-temperature geothermal resources, the first step was to analyse the energy demand of the societies residing in the five above-mentioned areas by assessing their economic activities. Then, the most suitable methods to meet the energy needs and pave the way for new economic and social development opportunities were identified. It was found that the most effective way to harness low- to medium-temperature geothermal resources in Tanzania is to use them as the direct heat source in greenhouses, preservation of crops and animal products, hatcheries, aquaculture, geothermal spas, and balneotherapy. Binary (Organic Rankine Cycle) power plants might also suit small, isolated populations with low energy demands. Implementing these forms of utilisation is expected to stimulate economic growth by creating employment opportunities, promoting the development of agro-processing industries, and paving the way for new business prospects. Some major challenges include insufficient reservoir knowledge, high capital costs, shortage of funds and experts, and poor infrastructure. These challenges could be overcome if the government actively invests in developing low- to medium-temperature geothermal resources to benefit the local societies and the whole country. This qualitative study provides insight into the effective utilisation of low- to medium-temperature geothermal systems, obstacles and opportunities related to their development in Tanzania. However, a detailed quantitative economic analysis is required to evaluate the feasibility of the suggested applications.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"129 ","pages":"Article 103288"},"PeriodicalIF":3.5,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143454618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polynomial chaos-based uncertainty quantification of the performance of a closed loop deep geothermal borehole","authors":"T.S. Charlton,&nbsp;M. Rouainia","doi":"10.1016/j.geothermics.2025.103271","DOIUrl":"10.1016/j.geothermics.2025.103271","url":null,"abstract":"<div><div>Geothermal energy has the potential to become a key technology in the transition away from fossil fuels. Deep borehole heat exchangers (DBHEs) are closed loop geothermal systems, and one benefit of a closed loop is that existing wells can be repurposed, reducing development costs. Although modelling of DBHEs has advanced in recent years, the effect of uncertainty in geological properties has not been widely explored, particularly when the borehole penetrates diverse rock strata. This paper uses polynomial chaos expansions to quantify the effect of thermogeological uncertainty on the performance of a closed loop deep geothermal borehole. The focus is on the Science Central borehole in Newcastle upon Tyne, UK, which was drilled 1820 m through a heterogenous sedimentary basin and is a candidate for repurposing as a DBHE. A recent semi-analytical model of a coaxial DBHE is extended to account for variable heat loads and combined with an energy demand model for a neighbouring building. The results show that the DBHE could support a 20-year constant heat load of between 132 (P90) and 154 kWth (P10) and over 90% of the variability in this long-term output is governed by rock thermal conductivity. Investigation of a year-long variable heat load revealed that while deeper formations generally control heat transfer, shallower formations grow in importance during times of lower heat demand and cooling. Using mean geological properties could be unconservative as a deterministic model with a minimum predicted temperature of 7.1 °C over one year had a non-negligible failure probability of order <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>5</mn></mrow></msup></mrow></math></span>.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"129 ","pages":"Article 103271"},"PeriodicalIF":3.5,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143454619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}