Geothermal EnergyPub Date : 2024-10-22DOI: 10.1186/s40517-024-00317-2
Ábel Markó, Maren Brehme, Daniele Pedretti, Günter Zimmermann, Ernst Huenges
{"title":"Controls of low injectivity caused by interaction of reservoir and clogging processes in a sedimentary geothermal aquifer (Mezőberény, Hungary)","authors":"Ábel Markó, Maren Brehme, Daniele Pedretti, Günter Zimmermann, Ernst Huenges","doi":"10.1186/s40517-024-00317-2","DOIUrl":"10.1186/s40517-024-00317-2","url":null,"abstract":"<div><p>Low injectivity is often experienced in geothermal doublets installed in sandstone reservoirs. This even led to a shutdown of the Mezőberény (Hungary) geothermal site. An on-site campaign was carried out in January 2021 to prepare a stimulation aiming to enhance the transmissivity of the sedimentary reservoir and the near-wellbore zone of this site. Previous studies have concluded that insufficient injectivity may be linked to a high skin effect in the near well-bore zone and pore clogging in combination with the low net sandstone content of the fluvio-deltaic reservoir. A chemical soft stimulation based on the injection of hydrochloric acid (HCl) was successfully used to unclog and recover the well injectivity. Despite such empirical evidence, the geochemical mechanisms leading to both, detrimental formation of clogging and the HCl-driven transmissivity restoration, have not yet been elucidated. This work presents the results of a novel analysis aiming at (a) predicting the dominant type of clogging forming in the near-well bore zone; (b) quantifying the drop in hydraulic conductivity as clogging occurs; and (c) supporting the optimization of the HCl dosage during the chemical soft stimulation. The study is supported by new experimental datasets never presented before from the Mezőberény site and a geochemical model set-up simulating the main mechanisms involved in the clogging and unclogging processes. It is concluded that the biofilm formation was the dominant, while the precipitation of calcite and amorphous ferrihydrite—later reduced to magnetite by microbes—was the secondary clogging mechanism: In the long-term (yearly scale) simulating the hydraulic conductivity showed a decline with forming scales; therefore, biofilm was presumably responsible for the experienced rapid (1 month) clogging. When modelling the chemical stimulation, the estimated amount of precipitated minerals was dissolved already with 2.5 mol of HCl per liter of water (~ 10 m/m%). Therefore, the 20 m/m% of HCl chosen during the field campaign might had a beneficial effect dissolving the potentially higher amount of scaling and/or the carbonate minerals of the matrix near the wellbore. Overall, it is concluded that the chemical and the microbial analyses together with the geochemical model were critical to tailor the remediation attempts and to propose further development or reconstruction of the surface system before going into operation to prevent recurrent impairments. Our findings highlight the importance of interactions of various clogging mechanisms with each other as well as with the reservoir processes and provide approaches to tackle the issue of injectivity drop by characterizing and quantifying their effects.</p></div>","PeriodicalId":48643,"journal":{"name":"Geothermal Energy","volume":"12 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geothermal-energy-journal.springeropen.com/counter/pdf/10.1186/s40517-024-00317-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142519072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Density of pure and mixed NaCl and CaCl2 aqueous solutions at 293 K to 353 K and 0.1 MPa: an integrated comparison of analytical and numerical data","authors":"Ulrike Hoffert, Laurent André, Guido Blöcher, Sylvain Guignot, Arnault Lassin, Harald Milsch, Ingo Sass","doi":"10.1186/s40517-024-00318-1","DOIUrl":"10.1186/s40517-024-00318-1","url":null,"abstract":"<div><p>This study reports on newly acquired density data of synthetically prepared pure and mixed NaCl and CaCl<sub>2</sub> aqueous solutions that span a wide range of geothermally encountered concentrations and mixing ratios. The analytical data are provided for the temperature range of 293–353 K at ambient pressure. For the reproduction of that data, PHREESCALE was used. The predictive potential of this numerical tool regarding the density of geothermal fluids of known composition was the major target herein. As a result, the measured data are in good agreement with previous analytical studies found in the literature. Possible sources of errors are discussed in this paper. Density data of the mixed solutions at temperatures other than ambient are unique and close existing data gaps. The numerical model reproduces the newly measured and already existing density data within an error band of approximately 1%. For further use in geothermal applications, this can be considered an excellent agreement. Moreover, the model yields a direct calculation of density without the need to establish complex empirical equations of state and mixing rules. Finally, sensitivity calculations performed with a thermal–hydraulic (TH) numerical reservoir model demonstrate the required accuracy of fluid density for reliably predicting the long-term performance of deep geothermal energy systems. In terms of the productivity index and the timing of thermal breakthrough it shows that the present analytical and numerical uncertainty in density is small enough to reliably state both reservoir parameters.</p></div>","PeriodicalId":48643,"journal":{"name":"Geothermal Energy","volume":"12 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geothermal-energy-journal.springeropen.com/counter/pdf/10.1186/s40517-024-00318-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142451068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Geothermal EnergyPub Date : 2024-10-08DOI: 10.1186/s40517-024-00312-7
Akihiro Shima, Kazuya Ishitsuka, Weiren Lin, Elvar K. Bjarkason, Anna Suzuki
{"title":"Modeling unobserved geothermal structures using a physics-informed neural network with transfer learning of prior knowledge","authors":"Akihiro Shima, Kazuya Ishitsuka, Weiren Lin, Elvar K. Bjarkason, Anna Suzuki","doi":"10.1186/s40517-024-00312-7","DOIUrl":"10.1186/s40517-024-00312-7","url":null,"abstract":"<div><p>Deep learning has gained attention as a potentially powerful technique for modeling natural-state geothermal systems; however, its physical validity and prediction inaccuracy at extrapolation ranges are limiting. This study proposes the use of transfer learning in physics-informed neural networks to leverage prior expert knowledge at the target site and satisfy conservation laws for predicting natural-state quantities such as temperature, pressure, and permeability. A neural network pre-trained with multiple numerical datasets of natural-state geothermal systems was generated using numerical reservoir simulations based on uncertainties of the permeabilities, sizes, and locations of geological units. Observed well logs were then used for tuning by transfer learning of the network. Two synthetic datasets were examined using the proposed framework. Our results demonstrate that the use of transfer learning significantly improves the prediction accuracy in extrapolation regions with no observed wells.</p></div>","PeriodicalId":48643,"journal":{"name":"Geothermal Energy","volume":"12 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geothermal-energy-journal.springeropen.com/counter/pdf/10.1186/s40517-024-00312-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142397581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Geothermal EnergyPub Date : 2024-10-06DOI: 10.1186/s40517-024-00313-6
Petr Nakládal, Martin Procházka, Viktor Goliáš, Jaromíra Hrdá
{"title":"Methods of grout quality measurement in borehole exchangers for heat pumps and their rehabilitation","authors":"Petr Nakládal, Martin Procházka, Viktor Goliáš, Jaromíra Hrdá","doi":"10.1186/s40517-024-00313-6","DOIUrl":"10.1186/s40517-024-00313-6","url":null,"abstract":"<div><p>Methods and instrumentation for measuring grout quality in heat pump boreholes, including the measurement of groundwater flow through boreholes outside partly grouted borehole exchanger pipes, have been developed in the Czech Republic. A Semtex charge has also been developed to repair rock massifs, which reliably disconnects borehole exchanger pipes without severely harming the surrounding rock environment or buildings. The resulting hole can then be used for regrouting, thus preventing undesirable vertical water flow through the borehole.</p></div>","PeriodicalId":48643,"journal":{"name":"Geothermal Energy","volume":"12 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geothermal-energy-journal.springeropen.com/counter/pdf/10.1186/s40517-024-00313-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142383513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Geothermal EnergyPub Date : 2024-09-28DOI: 10.1186/s40517-024-00314-5
Octavio Castillo-Reyes, Rosa María Prol-Ledesma, Fernando Corbo-Camargo, Otilio Rojas
{"title":"Geothermal resources in Latin-America and their exploration using electromagnetic methods","authors":"Octavio Castillo-Reyes, Rosa María Prol-Ledesma, Fernando Corbo-Camargo, Otilio Rojas","doi":"10.1186/s40517-024-00314-5","DOIUrl":"10.1186/s40517-024-00314-5","url":null,"abstract":"<div><p>The global priority for sustainable societies drives the transition to green energy, with geothermal power as a promising alternative. Latin-American countries benefit from the active volcanism along the Pacific Rim, which fuels their significant geothermal potential. Geothermal electricity production in the region is steadily growing and currently represents approximately <span>(11%)</span> of global output (16 GW). This paper provides details on the installed capacity of electrical generation in the most geothermally significant Latin-American countries, as well as the estimated potential production from existing prospects in the region. We also discuss the multiple challenges that limit the widespread development and exploitation of this valuable resource in Latin-America. As México stands as the top electricity producer in the region and ranks sixth worldwide, we offer an overview of its geothermal potential, the use of electromagnetic imaging technologies to enhance Mexican geothermal resource exploration, and the challenges and limitations associated with traditional exploration techniques. Additionally, we present recent case studies on the combined use of these technologies in México, highlighting best practices and lessons learned. The paper identifies open questions and outlines future research directions, particularly in México, to unlock the geothermal potential of the entire region.</p></div>","PeriodicalId":48643,"journal":{"name":"Geothermal Energy","volume":"12 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geothermal-energy-journal.springeropen.com/counter/pdf/10.1186/s40517-024-00314-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142328436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Geothermal EnergyPub Date : 2024-09-28DOI: 10.1186/s40517-024-00315-4
Nora Koltzer, Johannes Schoenherr, Maximilian Sporleder, Jan Niederau, Florian Wellmann
{"title":"Repurposing idle wells in the North German Basin as deep borehole heat exchangers","authors":"Nora Koltzer, Johannes Schoenherr, Maximilian Sporleder, Jan Niederau, Florian Wellmann","doi":"10.1186/s40517-024-00315-4","DOIUrl":"10.1186/s40517-024-00315-4","url":null,"abstract":"<div><p>This study investigates the feasibility to repurpose wells from gas production for geothermal closed-loop application in the North German Basin (NGB). The objective for this research topic is to extend the value-added chain of idle wells by re-completion as coaxial deep borehole heat exchangers as an efficient way to produce green energy without drilling new wells by saving the carbon emission and costs of building a new geothermal well. With numerical models of two typical geological settings of the NGB and two different completion schemes, it is possible to simulate the thermal performance over a lifetime of 30 years. The calculated heat extraction rates range from 200 to 400 kW, with maximum values of up to 600 kW. Sensitivity analyses demonstrate that re-completion depth and injection temperature are the most sensitive parameters of thermal output determination. The heat demand around the boreholes is mapped, and heat generation costs are calculated with heating network simulations. The initial production costs for heat are comparable to other renewable energy resources like biomass and competitive against gas prices in 2022. This study highlights available geothermal resources’ environmental and economic potential in already installed wells. The application has almost no geological and no drilling risks and may be installed at any idle well location.</p></div>","PeriodicalId":48643,"journal":{"name":"Geothermal Energy","volume":"12 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geothermal-energy-journal.springeropen.com/counter/pdf/10.1186/s40517-024-00315-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142328443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Geothermal EnergyPub Date : 2024-09-28DOI: 10.1186/s40517-024-00316-3
Anna Albers, Petra Huttenloch, Roman Zorn, Hagen Steger, Philipp Blum
{"title":"Determination of thermal properties of grouting materials for borehole heat exchangers (BHE)","authors":"Anna Albers, Petra Huttenloch, Roman Zorn, Hagen Steger, Philipp Blum","doi":"10.1186/s40517-024-00316-3","DOIUrl":"10.1186/s40517-024-00316-3","url":null,"abstract":"<div><p>Thermal properties of grouting materials for borehole heat exchangers (BHE) are currently analysed with varying measurement methods and analysis procedures, resulting in difficulties when comparing values of different studies. This study therefore provides the first comprehensive investigation of different analysis procedures by systematically comparing the influence of the measurement method and the sample preparation on the determination of the thermal conductivity and the volumetric heat capacity. Seven dissimilar grouting materials with varying water–solid ratios (W/S) and compositions are analysed. The thermal conductivities of the materials range between 0.9 and 1.8 W m<sup>−1</sup> K<sup>−1</sup> (transient plane source method, TPS). The volumetric heat capacities range between 3.01 and 3.63 MJ m<sup>−3</sup> K<sup>−1</sup> (differential scanning calorimetry, DSC). From the findings of this study, a standardised analysis of grouting materials is provided which suggests mixing of the grouting material at a high mixing speed and sample curing under water for 28 days at room temperature. The benefits of calculating the volumetric heat capacities of grouting materials from the specific heat capacities of dry samples measured with the DSC, the water content and the bulk density are demonstrated. Furthermore, an estimation procedure of volumetric heat capacity from the W/S and suspension density with an uncertainty of smaller ± 5% is provided. Finally, this study contributes to consistency and comparability between existing and future studies on the thermal properties of grouting materials.</p></div>","PeriodicalId":48643,"journal":{"name":"Geothermal Energy","volume":"12 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geothermal-energy-journal.springeropen.com/counter/pdf/10.1186/s40517-024-00316-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142329388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Chemical and isotopic constraints on fluid origin and genesis of geothermal systems in the Tingri-Tangra Yumco rift, southern Tibetan Plateau","authors":"Wei Liu, Maoliang Zhang, Yi Liu, Lifeng Cui, Yuji Sano, Sheng Xu","doi":"10.1186/s40517-024-00311-8","DOIUrl":"10.1186/s40517-024-00311-8","url":null,"abstract":"<div><p>Numerous geothermal systems are hosted by extensional rifts that transect the Himalayas and Lhasa block in the Himalayan–Tibetan orogen. However, the relationships between hydrogeological processes and geothermal fluid circulation in different tectonic units remain unclear. Here, we report an integrated dataset of chemical and isotopic compositions (including major and trace elements, δD, δ<sup>18</sup>O, and <sup>87</sup>Sr/<sup>86</sup>Sr) of thermal spring water from the Tingri-Tangra Yumco rift to assess their origins and circulation processes. δ<sup>18</sup>O (− 21.3 to − 17.0‰) and δD (− 166 to − 135‰) values of thermal springs indicate dominant recharge of meteoric waters from areas with elevation of > 6000 m and minor addition of magmatic fluids. Meteoric water could infiltrate to depths of about 1700–2900 m along the faults, whereby it is influenced by geothermal gradient and/or conductive heat transfer of magmatic fluids. The thermal spring waters are mainly Na-HCO<sub>3</sub> type and are controlled by dissolution of silicate and carbonate minerals and mixing with deep fluids. The results of chemical and multicomponent geothermometers indicate reservoir temperatures of 115 − 195 ℃, corresponding to a convection heat flux of 3.96 × 10<sup>5</sup> J/s to 1.78 × 10<sup>7</sup> J/s from geothermal systems, which are comparable to that of the low-enthalpy geothermal systems in southern Italy. Geochemical modeling is conducted to assess the water–mineral equilibria in the reservoir. Trace elements and <sup>87</sup>Sr/<sup>86</sup>Sr data suggest spatially variable controlling factors for the rift-related geothermal systems: (1) interaction with granitoid and carbonate in the Himalayas; (2) cold groundwater mixing with that leaching from granite and volcanic rocks in the Lhasa block; (3) the input of vapors from magmatic degassing. The geochemistry of thermal springs associated with extensional rift is largely induced by the interaction between fluid and different reservoir rocks in the Himalayas and Lhasa block. Based on these findings, a genetic model is proposed for exploration and development of geothermal resources in the Tingri-Tangra Yumco rift.</p></div>","PeriodicalId":48643,"journal":{"name":"Geothermal Energy","volume":"12 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geothermal-energy-journal.springeropen.com/counter/pdf/10.1186/s40517-024-00311-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142123084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Geothermal EnergyPub Date : 2024-08-28DOI: 10.1186/s40517-024-00309-2
Lioba Virchow, Christian Siever-Wenzlaff, Guido Blöcher, Armando Alibrandi, Jens Kallmeyer, Martin Zimmer, Thomas Wiersberg, Christoph Thielke, Anja Schleicher, Simona Regenspurg
{"title":"Hydrogeochemical and microbial characterization of a Middle Triassic carbonate aquifer (Muschelkalk) in Berlin and geochemical simulation of its use as a high-temperature aquifer thermal energy storage","authors":"Lioba Virchow, Christian Siever-Wenzlaff, Guido Blöcher, Armando Alibrandi, Jens Kallmeyer, Martin Zimmer, Thomas Wiersberg, Christoph Thielke, Anja Schleicher, Simona Regenspurg","doi":"10.1186/s40517-024-00309-2","DOIUrl":"10.1186/s40517-024-00309-2","url":null,"abstract":"<div><p>The geological formation of the Muschelkalk is widespread in the center of the North German Basin (NGB) and is increasingly attracting interest for application of geothermal energy extraction or high-temperature aquifer thermal energy storage (HT-ATES). This study investigates the Middle Triassic <i>“Rüdersdorfer Schaumkalk”</i>, which was the former injection horizon of the natural gas storage facility in Berlin, Germany. For the first time, detailed chemical and microbiological analyses of formation water of this Lower Muschelkalk limestone formation were conducted and hydrogeochemically characterized. In addition, a hydrogeochemical model was developed to quantify the potential reactions during HT-ATES focusing on calcite dissolution and precipitation. The main objectives of this study are: (1) to determine the origin of the water from the three wells targeting the Muschelkalk aquifer, (2) to understand changes in hydrochemistry after system operation, and (3) to evaluate the long-term sustainability of a potential HT-ATES system with increasing temperature. The target formation is encountered by several wells at about 525 m below the surface with an average thickness of 30 m. Two hydraulic lifting tests including physical, chemical, and microbial groundwater as well as gas monitoring were carried out. In addition, several downhole samples of formation fluid were collected from the aquifer at in situ pressure and temperature conditions. Fluid analysis of the saline formation water indicate a seawater origin within the Muschelkalk with subsequent evaporation and various water–rock interactions with anhydrite/gypsum, dolomite, and calcite. With a salinity of 130 g/L, dominated by Na–Cl, a slightly acidic pH between 6 and 7, and a low gas content of 3%, the formation water fits to other saline deep formation waters of the NGB. Gas concentrations and microbial communities like sulfate-reducing bacteria and methanogenic archaea in the produced water indicate several geochemical alterations and microbial processes like corrosion and the forming of biogenic methane. Geochemical simulations of calcite equilibrium over 10 HT-ATES cycles indicated a pronounced propensity for calcite precipitation up to 31 mg/kgw, within the heat exchanger. At the same time, these models predicted a significant potential for calcite dissolution, with rates up to 21 mg/kgw, in both the cold and hot reservoirs. The results from the carbonate aquifer characterized in this study can be transferred to other sites in the NGB affected by salt tectonics and have provided information on the microbiological-chemical processes to be expected during the initial use of old wells.</p></div>","PeriodicalId":48643,"journal":{"name":"Geothermal Energy","volume":"12 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geothermal-energy-journal.springeropen.com/counter/pdf/10.1186/s40517-024-00309-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142091151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Geothermal EnergyPub Date : 2024-08-23DOI: 10.1186/s40517-024-00310-9
Saghar Sarshar, Kobra Gharali, Meghdad Saffaripour, Jatin Nathwani, Maurice B. Dusseault
{"title":"Multi-objective optimization and long-time simulation of a multi-borehole ground heat exchanger system","authors":"Saghar Sarshar, Kobra Gharali, Meghdad Saffaripour, Jatin Nathwani, Maurice B. Dusseault","doi":"10.1186/s40517-024-00310-9","DOIUrl":"10.1186/s40517-024-00310-9","url":null,"abstract":"<div><p>Multi-objective optimization and CFD simulation are conducted to optimize the design of a multi-borehole ground heat exchanger (GHE) system and assess its long-time performance. The multi-objective optimization is performed to minimize the entropy generation number (EGN) and total cost rate by using various evolutionary algorithms, including NSGA-II, GDE-3, MOEA/D, PESA-II, SPEA-II, and SMPSO. NSGA-II and GDE-3 algorithms perform best in obtaining Pareto optimal solutions. Three prominent points on the NSGA-II Pareto frontier, representing the results of single-objective thermodynamic, single-objective economic, and multi-objective optimizations, are simulated in three dimensions over three months. The trends of EGN variations extracted from the transient CFD simulation agree well with those from the steady analytical model. The EGN obtained from multi-objective optimization is 58.8% lower than the EGN obtained using single-objective economic optimization and 1.9 times higher than that calculated from single-objective thermodynamic optimization. Likewise, the total cost rate obtained from multi-objective optimization is 64.4% lower than the value obtained from single-objective thermodynamic optimization and four times higher than that calculated using single-objective economic optimization. The proposed optimization approach can be reliably applied to improve the design of multi-borehole GHE systems.</p></div>","PeriodicalId":48643,"journal":{"name":"Geothermal Energy","volume":"12 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geothermal-energy-journal.springeropen.com/counter/pdf/10.1186/s40517-024-00310-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142045151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}