Pub Date : 2026-01-24DOI: 10.1016/j.enconman.2026.121107
Daneun Kim , Juneyeol Jung , Jaeheuk Choi , Hoseong Lee
The electrification of heating and domestic hot-water systems in Korean multi-family residential buildings is not well understood, as most studies overlook their distinct hydronic features—low-temperature radiant-floor heating, synchronized DHW demand, and large vertical distribution losses. This study develops an integrated TRNSYS-based dynamic framework that captures these constraints and evaluates stepwise electrification pathways rather than only end-state systems. After screening key design variables to establish realistic boundary conditions, four transition scenarios are assessed: a boiler baseline, a hybrid retrofit with central ASHP DHW, a mixed system with individual ASHP heating and central DHW, and a fully individual ASHP configuration. Results show that the fully individual system delivers the highest seasonal efficiency, reducing primary energy use and CO2 emissions by up to 43% and 41% relative to the baseline. Intermediate stages also offer practical benefits, with hybrid and mixed configurations improving feasibility and reducing gas use under existing hydronic constraints. Overall, the study provides a practical and context-specific assessment framework for electrifying high-density apartment buildings, emphasizing that effective decarbonization requires staged, system-specific transition strategies tailored to Korean building conditions.
{"title":"Dynamic assessment of electrification pathways for heating and hot water in Korean Multi-Family residential buildings","authors":"Daneun Kim , Juneyeol Jung , Jaeheuk Choi , Hoseong Lee","doi":"10.1016/j.enconman.2026.121107","DOIUrl":"10.1016/j.enconman.2026.121107","url":null,"abstract":"<div><div>The electrification of heating and domestic hot-water systems in Korean multi-family residential buildings is not well understood, as most studies overlook their distinct hydronic features—low-temperature radiant-floor heating, synchronized DHW demand, and large vertical distribution losses. This study develops an integrated TRNSYS-based dynamic framework that captures these constraints and evaluates stepwise electrification pathways rather than only end-state systems. After screening key design variables to establish realistic boundary conditions, four transition scenarios are assessed: a boiler baseline, a hybrid retrofit with central ASHP DHW, a mixed system with individual ASHP heating and central DHW, and a fully individual ASHP configuration. Results show that the fully individual system delivers the highest seasonal efficiency, reducing primary energy use and CO<sub>2</sub> emissions by up to 43% and 41% relative to the baseline. Intermediate stages also offer practical benefits, with hybrid and mixed configurations improving feasibility and reducing gas use under existing hydronic constraints. Overall, the study provides a practical and context-specific assessment framework for electrifying high-density apartment buildings, emphasizing that effective decarbonization requires staged, system-specific transition strategies tailored to Korean building conditions.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"352 ","pages":"Article 121107"},"PeriodicalIF":10.9,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-24DOI: 10.1016/j.enconman.2026.121111
Ran Yao, Sajad Jafari, Christophe Duwig
Enhancing heat transfer in turbulent convection has been a long-standing challenge in many energy and industrial processes. However, despite decades of efforts, conventional strategies have achieved only limited success, due to the intrinsic bounds of turbulent mixing. Inspired by thermal-chemical energy conversion, this work unlocks a fundamentally new route for intensified heat transfer by introducing a reversible chemical reaction (N2O4 ↔ 2NO2) into Rayleigh-Bénard convection. The resulting reactive convection achieves an unprecedented increase in heat transfer (over seven times) relative to conventional non-reactive fluids. The underlying mechanism is described by a simplified double-film model: heat is absorbed as chemical energy in an endothermic film near the heated wall, then transported by reaction-intensified turbulence, and finally releases in an exothermic film near the cold wall. Unsteady analysis further confirms the coupling between chemical reaction and turbulence, particularly the coherent structures. Beyond advancing thermal convection theory, the approach offers practical potential for low-temperature waste-heat recovery where reaction reversibility is maintained, and for the design of gaseous space thermal management system.
{"title":"Intensified turbulent thermal convection with reversible reactive fluid","authors":"Ran Yao, Sajad Jafari, Christophe Duwig","doi":"10.1016/j.enconman.2026.121111","DOIUrl":"10.1016/j.enconman.2026.121111","url":null,"abstract":"<div><div>Enhancing heat transfer in turbulent convection has been a long-standing challenge in many energy and industrial processes. However, despite decades of efforts, conventional strategies have achieved only limited success, due to the intrinsic bounds of turbulent mixing. Inspired by thermal-chemical energy conversion, this work unlocks a fundamentally new route for intensified heat transfer by introducing a reversible chemical reaction (N<sub>2</sub>O<sub>4</sub> ↔ 2NO<sub>2</sub>) into Rayleigh-Bénard convection. The resulting reactive convection achieves an unprecedented increase in heat transfer (over seven times) relative to conventional non-reactive fluids. The underlying mechanism is described by a simplified double-film model: heat is absorbed as chemical energy in an endothermic film near the heated wall, then transported by reaction-intensified turbulence, and finally releases in an exothermic film near the cold wall. Unsteady analysis further confirms the coupling between chemical reaction and turbulence, particularly the coherent structures. Beyond advancing thermal convection theory, the approach offers practical potential for low-temperature waste-heat recovery where reaction reversibility is maintained, and for the design of gaseous space thermal management system.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"352 ","pages":"Article 121111"},"PeriodicalIF":10.9,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146033467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-24DOI: 10.1016/j.enconman.2026.121093
Jay Wang
This study has comprehensively compared and analysed CO2 heat pump dryers operating under closed-loop and open-loop air cycles to evaluate their energy efficiency and drying performance. Unlike the conventional closed-loop air cycle that uses dry recirculated air as its inlet, the open-loop air cycle operates only with fresh ambient air. The physical models and working principles have been illustrated using psychrometric charts, and the influence of moisture variation has been considered in the fin-and-tube heat exchanger design for both the gas cooler and the evaporator. In the case study under typical hot and humid climate conditions (ambient temperature of 40 °C), the simulation compares three cycles over an air mass flow rate ranging from 0.5 kg/s to 1 kg/s. The open-loop air cycle with a wet air outlet achieves the largest heating capacity, i.e.: 17.44 kW at 1 kg/s, because the air is cooled in the evaporator first, allowing a greater temperature rise in the gas cooler. The open-loop air cycle with a dry air outlet produces the highest air temperature after the gas cooler, i.e.: 60.8 °C at 0.5 kg/s, which increases the air’s moisture absorption capacity. Compared with the closed-loop air cycle, the open-loop air cycle with dry air outlet proves more efficient for drying, delivering a shorter drying time (27.77 min at 0.5 kg/s) and a higher drying efficiency (0.8640 kg/kWh at 0.5 kg/s). Although the open-loop air cycle with a wet air outlet achieves the highest coefficient of performance of 2.31 at 1 kg/s, its drying performance declines obviously at higher mass flow rates, with specific moisture extraction rate dropping to 0.0767 kg/kWh. Overall, the configuration of open-loop air cycle with dry air outlet is the superior option, as it combines the shortest drying time and the highest specific moisture extraction rate, which are two critical metrics for heat pump dryers.
{"title":"A comparative conceptual analysis of CO2 heat pump dryers with closed-loop and open-loop air cycles","authors":"Jay Wang","doi":"10.1016/j.enconman.2026.121093","DOIUrl":"10.1016/j.enconman.2026.121093","url":null,"abstract":"<div><div>This study has comprehensively compared and analysed CO<sub>2</sub> heat pump dryers operating under closed-loop and open-loop air cycles to evaluate their energy efficiency and drying performance. Unlike the conventional closed-loop air cycle that uses dry recirculated air as its inlet, the open-loop air cycle operates only with fresh ambient air. The physical models and working principles have been illustrated using psychrometric charts, and the influence of moisture variation has been considered in the fin-and-tube heat exchanger design for both the gas cooler and the evaporator. In the case study under typical hot and humid climate conditions (ambient temperature of 40 °C), the simulation compares three cycles over an air mass flow rate ranging from 0.5 kg/s to 1 kg/s. The open-loop air cycle with a wet air outlet achieves the largest heating capacity, i.e.: 17.44 kW at 1 kg/s, because the air is cooled in the evaporator first, allowing a greater temperature rise in the gas cooler. The open-loop air cycle with a dry air outlet produces the highest air temperature after the gas cooler, i.e.: 60.8 °C at 0.5 kg/s, which increases the air’s moisture absorption capacity. Compared with the closed-loop air cycle, the open-loop air cycle with dry air outlet proves more efficient for drying, delivering a shorter drying time (27.77 min at 0.5 kg/s) and a higher drying efficiency (0.8640 kg/kWh at 0.5 kg/s). Although the open-loop air cycle with a wet air outlet achieves the highest coefficient of performance of 2.31 at 1 kg/s, its drying performance declines obviously at higher mass flow rates, with specific moisture extraction rate dropping to 0.0767 kg/kWh. Overall, the configuration of open-loop air cycle with dry air outlet is the superior option, as it combines the shortest drying time and the highest specific moisture extraction rate, which are two critical metrics for heat pump dryers.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"352 ","pages":"Article 121093"},"PeriodicalIF":10.9,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-24DOI: 10.1016/j.enconman.2026.121118
Bikash Kumar, Y. Naresh, J. Banerjee
Efficient thermal regulation of compact electronic devices remains a critical challenge as power densities continue to increase, necessitating effective passive cooling solutions. In PCM-based thermal management systems, the discharge cycle is just as important as the charging cycle, but it is often not studied enough. This work experimentally investigates in detail four different configurations of a heat sink (HS) with a phase change material (PCM): (i) a PCM-filled heat sink (PHS), (ii) a PCM-filled finned heat sink (PFHS), (iii) a PCM-filled finned heat sink integrated with a heat pipe (PFHSHP), and (iv) a PCM-filled finned heat sink coupled with a finned heat pipe (PFHSFHP). Docosane is the selected phase change material, and the tests are carried out at different power inputs (6, 8, 10, and 12 W) and controlled surrounding temperatures (24, 26, and 28 °C). The findings reveal that thermal performance depends to a large extent on the configuration and ambient conditions, and better performance is achieved at surrounding temperature of 24 °C. Among the investigated designs, the PFHSFHP configuration consistently exhibits the best charging and discharging performance across all operating conditions. For example, at an 8 W power level and ST = 28 °C, the percentage improvement in charging time in PFHSFHP compared to PHS, PFHS, and PFHSHP is 35.49 %, 34.06 %, and 27.54 % respectively. Under the same conditions, the percentage reduction in discharging time is 30.94 %, 18.78 %, and 11.99 % respectively. The performance increase is mainly due to better heat spreading and faster heat rejection, which were made possible by the finned condenser section of the heat pipe, which maintained a higher thermal driving potential during both the melting and solidification of the PCM. Energy-based thermodynamic analysis further confirms the dominant role of the heat pipe in heat transport, particularly during the discharging phase. In summary, the PFHSFHP setup is a powerful and reliable passive thermal management method that can be utilized for the next generation of miniaturized electronic devices, offering extended thermal buffering, accelerated heat dissipation, and enhanced operational stability.
{"title":"A PCM based finned heat sink coupled with a finned heat pipe is an efficient thermal management option for portable electronic gadgets","authors":"Bikash Kumar, Y. Naresh, J. Banerjee","doi":"10.1016/j.enconman.2026.121118","DOIUrl":"10.1016/j.enconman.2026.121118","url":null,"abstract":"<div><div>Efficient thermal regulation of compact electronic devices remains a critical challenge as power densities continue to increase, necessitating effective passive cooling solutions. In PCM-based thermal management systems, the discharge cycle is just as important as the charging cycle, but it is often not studied enough. This work experimentally investigates in detail four different configurations of a heat sink (HS) with a phase change material (PCM): (i) a PCM-filled heat sink (PHS), (ii) a PCM-filled finned heat sink (PFHS), (iii) a PCM-filled finned heat sink integrated with a heat pipe (PFHSHP), and (iv) a PCM-filled finned heat sink coupled with a finned heat pipe (PFHSFHP). Docosane is the selected phase change material, and the tests are carried out at different power inputs (6, 8, 10, and 12 W) and controlled surrounding temperatures (24, 26, and 28 °C). The findings reveal that thermal performance depends to a large extent on the configuration and ambient conditions, and better performance is achieved at surrounding temperature of 24 °C. Among the investigated designs, the PFHSFHP configuration consistently exhibits the best charging and discharging performance across all operating conditions. For example, at an 8 W power level and S<sub>T</sub> = 28 °C, the percentage improvement in charging time in PFHSFHP compared to PHS, PFHS, and PFHSHP is 35.49 %, 34.06 %, and 27.54 % respectively. Under the same conditions, the percentage reduction in discharging time is 30.94 %, 18.78 %, and 11.99 % respectively. The performance increase is mainly due to better heat spreading and faster heat rejection, which were made possible by the finned condenser section of the heat pipe, which maintained a higher thermal driving potential during both the melting and solidification of the PCM. Energy-based thermodynamic analysis further confirms the dominant role of the heat pipe in heat transport, particularly during the discharging phase. In summary, the PFHSFHP setup is a powerful and reliable passive thermal management method that can be utilized for the next generation of miniaturized electronic devices, offering extended thermal buffering, accelerated heat dissipation, and enhanced operational stability.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"352 ","pages":"Article 121118"},"PeriodicalIF":10.9,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146033468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-24DOI: 10.1016/j.enconman.2026.121082
Ömer Faruk Görçün , Gülay Demir , Dragan Pamucar , Vladimir Simic
<div><div>Storing hydrogen resources underground can accelerate the transition to renewable energy, facilitate energy supply security, and the adoption and expansion of hydrogen energy, a clean energy source. The selection of sustainable underground hydrogen storage systems is a critical research topic for addressing environmental issues caused using fossil fuels. However, decision-makers still lack a consensus-based and sustainability-oriented framework that can comparatively evaluate alternative underground hydrogen storage geological formations under economic, environmental, social, and technical uncertainties, which constitutes a critical barrier to large-scale hydrogen deployment. This issue has become more prominent as fossil-based fuel reserves are gradually decreasing worldwide. In contrast, researchers and practitioners lack a consensus on which underground storage method is most suitable for economical, safe, and efficient hydrogen storage. If this problem is not addressed correctly and reasonable solutions are not obtained, continued dependence on fossil fuels may persist. Alternatively, other renewable energy sources with relatively lower efficiency and performance may be adopted. In both cases, significant delays in achieving the global sustainability goal are likely to occur. We propose an integrated fuzzy decision-making framework (F-WENSLO & Dombi-Bonferroni & F-ARTASI) to address this selection problem under uncertainty. The proposed framework integrates fuzzy WENSLO (Weights by ENvelope and SLOpe) for robust sustainability-based criteria weighting, the Dombi–Bonferroni aggregation operator to model interdependencies among criteria explicitly, and the fuzzy ARTASI (Alternative Ranking Technique based on Adaptive Standardized Intervals) method to provide flexible and stable ranking of geological alternatives beyond rigid distance-based approaches. Key advantages of the proposed model include producing reliable and consistent solutions that accurately reflect real-world conditions for selecting sustainable underground hydrogen storage systems. The results revealed that C14 (job creation and employment opportunities) (0.0603) is the most influential criterion in selecting the most suitable storage system. In addition, salt caverns with an <span><math><mrow><msub><mi>Ω</mi><mi>i</mi></msub></mrow></math></span> of 10,5167 have achieved the highest score, placing them in the first position, and it is the most suitable and advantageous underground hydrogen storage option. The suggested decision-making tool can yield reliable and robust solutions in real-world conditions, enabling the planning of infrastructure design for hydrogen energy systems that incorporate sustainability dimensions. In that regard, the developed model possesses the characteristics of an efficient and practical roadmap that can guide policymakers and decision-makers in transitioning from fossil-based energy sources to renewable energy sources. It has been i
{"title":"Selection of underground hydrogen storage systems using a novel fuzzy model","authors":"Ömer Faruk Görçün , Gülay Demir , Dragan Pamucar , Vladimir Simic","doi":"10.1016/j.enconman.2026.121082","DOIUrl":"10.1016/j.enconman.2026.121082","url":null,"abstract":"<div><div>Storing hydrogen resources underground can accelerate the transition to renewable energy, facilitate energy supply security, and the adoption and expansion of hydrogen energy, a clean energy source. The selection of sustainable underground hydrogen storage systems is a critical research topic for addressing environmental issues caused using fossil fuels. However, decision-makers still lack a consensus-based and sustainability-oriented framework that can comparatively evaluate alternative underground hydrogen storage geological formations under economic, environmental, social, and technical uncertainties, which constitutes a critical barrier to large-scale hydrogen deployment. This issue has become more prominent as fossil-based fuel reserves are gradually decreasing worldwide. In contrast, researchers and practitioners lack a consensus on which underground storage method is most suitable for economical, safe, and efficient hydrogen storage. If this problem is not addressed correctly and reasonable solutions are not obtained, continued dependence on fossil fuels may persist. Alternatively, other renewable energy sources with relatively lower efficiency and performance may be adopted. In both cases, significant delays in achieving the global sustainability goal are likely to occur. We propose an integrated fuzzy decision-making framework (F-WENSLO & Dombi-Bonferroni & F-ARTASI) to address this selection problem under uncertainty. The proposed framework integrates fuzzy WENSLO (Weights by ENvelope and SLOpe) for robust sustainability-based criteria weighting, the Dombi–Bonferroni aggregation operator to model interdependencies among criteria explicitly, and the fuzzy ARTASI (Alternative Ranking Technique based on Adaptive Standardized Intervals) method to provide flexible and stable ranking of geological alternatives beyond rigid distance-based approaches. Key advantages of the proposed model include producing reliable and consistent solutions that accurately reflect real-world conditions for selecting sustainable underground hydrogen storage systems. The results revealed that C14 (job creation and employment opportunities) (0.0603) is the most influential criterion in selecting the most suitable storage system. In addition, salt caverns with an <span><math><mrow><msub><mi>Ω</mi><mi>i</mi></msub></mrow></math></span> of 10,5167 have achieved the highest score, placing them in the first position, and it is the most suitable and advantageous underground hydrogen storage option. The suggested decision-making tool can yield reliable and robust solutions in real-world conditions, enabling the planning of infrastructure design for hydrogen energy systems that incorporate sustainability dimensions. In that regard, the developed model possesses the characteristics of an efficient and practical roadmap that can guide policymakers and decision-makers in transitioning from fossil-based energy sources to renewable energy sources. It has been i","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"352 ","pages":"Article 121082"},"PeriodicalIF":10.9,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-24DOI: 10.1016/j.enconman.2026.121125
Ze Bai , Yaohua Zhao , Zhenhua Quan , Yiyang Liu , Wanli Chang
Conventional flat-plate photovoltaic/thermal (PVT) modules suffer from low solar energy utilization efficiency and unstable heat supply when used as heat pump evaporators. Additionally, their heat dissipation capabilities are limited when used as condensers. To address these limitations, this study proposes a novel micro heat pipe array-integrated PVT–air evaporator/condenser (MHPA-PVTAE/C), coupled with a dual-source direct expansion heat pump. Seasonal experiments were conducted to characterize its trigeneration performance, and an adaptive heating-mode switching strategy was developed using the coefficient of performance for heating (COP(H)) as the optimization objective based on solar irradiance and ambient temperature. The system achieved a COP(H) of 6.2 (summer) and 4.9 (winter), power generation efficiency of up to 14%, and a COP(C) of 2.7. Throughout continuous multi-day tests, the compressor exhaust temperature remained below 90 °C, and the suction/exhaust pressure variation rates were both below 5%, demonstrating reliable and stable operation when the MHPA-PVTAE/C functioned as the evaporator or condenser. Compared with existing systems, the novel system enhanced the COP(H) by 13.1–68.1% (summer) and 15.3–75.2% (winter), and increased the COP(C) by 5.2–42.4%, providing a validated technical route for building-scale trigeneration system.
{"title":"Research on the performance and mode switching strategy of the photovoltaic/thermal-air dual heat source direct expansion heat pump system based on micro heat pipe arrays","authors":"Ze Bai , Yaohua Zhao , Zhenhua Quan , Yiyang Liu , Wanli Chang","doi":"10.1016/j.enconman.2026.121125","DOIUrl":"10.1016/j.enconman.2026.121125","url":null,"abstract":"<div><div>Conventional flat-plate photovoltaic/thermal (PVT) modules suffer from low solar energy utilization efficiency and unstable heat supply when used as heat pump evaporators. Additionally, their heat dissipation capabilities are limited when used as condensers. To address these limitations, this study proposes a novel micro heat pipe array-integrated PVT–air evaporator/condenser (MHPA-PVTAE/C), coupled with a dual-source direct expansion heat pump. Seasonal experiments were conducted to characterize its trigeneration performance, and an adaptive heating-mode switching strategy was developed using the coefficient of performance for heating (<em>COP(H)</em>) as the optimization objective based on solar irradiance and ambient temperature. The system achieved a <em>COP(H)</em> of 6.2 (summer) and 4.9 (winter), power generation efficiency of up to 14%, and a <em>COP(C)</em> of 2.7. Throughout continuous multi-day tests, the compressor exhaust temperature remained below 90 °C, and the suction/exhaust pressure variation rates were both below 5%, demonstrating reliable and stable operation when the MHPA-PVTAE/C functioned as the evaporator or condenser. Compared with existing systems, the novel system enhanced the <em>COP(H)</em> by 13.1–68.1% (summer) and 15.3–75.2% (winter), and increased the <em>COP(C)</em> by 5.2–42.4%, providing a validated technical route for building-scale trigeneration system.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"352 ","pages":"Article 121125"},"PeriodicalIF":10.9,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fault detection in grid-connected photovoltaic (GCPV) systems is critical for ensuring operational safety and efficiency, yet the availability of labeled fault data in real-world deployments is limited. Reliable anomaly detection in GCPV systems is vital for ensuring operational safety, minimizing energy losses, and maintaining efficiency. This study presents a systematic, mode-aware benchmarking of semi-supervised anomaly detection methods for GCPV monitoring under realistic operating conditions. This study evaluates four semi-supervised techniques, Isolation Forest (iForest), Local Outlier Factor (LOF), One-Class SVM (1SVM), and Elliptic Envelope (EE), for fault detection in GCPV systems operating under Intermediate and Maximum Power Point Tracking (IPPT/MPPT) modes. Using the GPVS-Faults dataset, which contains simulated fault scenarios generated from a grid-connected PV system emulator, all models are trained exclusively on fault-free data, following a strictly semi-supervised paradigm, and evaluated across multiple metrics, including accuracy, F1-score, AUC, and false positive rate (FPR). Experimental results show that EE achieves the best average accuracy and AUC with the lowest FPR across both operating modes, reaching an average accuracy of 94.68% under MPPT and 93.54% under IPPT. LOF exhibits the highest sensitivity and F1-score, but at the expense of increased false positives, while iForest provides a balanced trade-off between precision and recall. Beyond detection performance, this work emphasizes reproducibility and interpretability in semi-supervised PV fault detection. To enhance transparency, SHapley Additive exPlanations (SHAP) analysis is used as a post-hoc interpretability layer based on an auxiliary XGBoost model, revealing fault-specific feature contributions aligned with physical system behavior. Overall, the results demonstrate complementary strengths among the evaluated methods and highlight the effectiveness of EE for low-false-alarm fault detection, alongside the value of lightweight, explainable, and mode-aware semi-supervised frameworks in supporting GCPV monitoring.
{"title":"Semi-supervised anomaly detection in photovoltaic systems under power tracking mode","authors":"Fouzi Harrou , Abdelkader Dairi , Abdelhakim Dorbane , Bilal Taghezouit , Ying Sun","doi":"10.1016/j.enconman.2026.121114","DOIUrl":"10.1016/j.enconman.2026.121114","url":null,"abstract":"<div><div>Fault detection in grid-connected photovoltaic (GCPV) systems is critical for ensuring operational safety and efficiency, yet the availability of labeled fault data in real-world deployments is limited. Reliable anomaly detection in GCPV systems is vital for ensuring operational safety, minimizing energy losses, and maintaining efficiency. This study presents a systematic, mode-aware benchmarking of semi-supervised anomaly detection methods for GCPV monitoring under realistic operating conditions. This study evaluates four semi-supervised techniques, Isolation Forest (iForest), Local Outlier Factor (LOF), One-Class SVM (1SVM), and Elliptic Envelope (EE), for fault detection in GCPV systems operating under Intermediate and Maximum Power Point Tracking (IPPT/MPPT) modes. Using the GPVS-Faults dataset, which contains simulated fault scenarios generated from a grid-connected PV system emulator, all models are trained exclusively on fault-free data, following a strictly semi-supervised paradigm, and evaluated across multiple metrics, including accuracy, F1-score, AUC, and false positive rate (FPR). Experimental results show that EE achieves the best average accuracy and AUC with the lowest FPR across both operating modes, reaching an average accuracy of 94.68% under MPPT and 93.54% under IPPT. LOF exhibits the highest sensitivity and F1-score, but at the expense of increased false positives, while iForest provides a balanced trade-off between precision and recall. Beyond detection performance, this work emphasizes reproducibility and interpretability in semi-supervised PV fault detection. To enhance transparency, SHapley Additive exPlanations (SHAP) analysis is used as a post-hoc interpretability layer based on an auxiliary XGBoost model, revealing fault-specific feature contributions aligned with physical system behavior. Overall, the results demonstrate complementary strengths among the evaluated methods and highlight the effectiveness of EE for low-false-alarm fault detection, alongside the value of lightweight, explainable, and mode-aware semi-supervised frameworks in supporting GCPV monitoring.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"352 ","pages":"Article 121114"},"PeriodicalIF":10.9,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-23DOI: 10.1016/j.enconman.2026.121064
Farah Souayfane , Ricardo M. Lima , Asaad Katoua , Omar Knio
Integrating large-scale renewable energy and storage systems is essential for sustainability in hot desert regions. However, resource variability and extreme weather pose operational and economic challenges, emphasizing the need for resilient systems. This study develops a TRNSYS simulation-based multi-objective optimization framework to design a resilient renewable energy system for a community in Saudi Arabia. Its novelty lies in the iterative incorporation of extreme weather derived from 25 years of historical weather data and the leveraging of sector coupling through the operational flexibility of a desalination plant. The optimization identifies optimal capacities for a system combining concentrated solar power, photovoltaic, and wind turbines, coupled with battery and thermal storage. The most economical off-grid configuration yields a life cycle cost of $1.46 billion and a levelized cost of energy of 0.1687 $/kWh with concentrated solar power supplying 96% of the energy (peak load of 86 MW and annual energy consumption of 505 GWh), which avoids 330,900 tonnes of emissions per year. This off-grid system, designed to withstand past extreme low solar radiation and high temperature days, requires additional generation and storage capacity, which increases the cost by 19%. Leveraging the desalination plant’s operational flexibility reduces the system’s cost by 2.7% while further enhancing system resilience. The framework provides a practical and adaptable method for designing resilient renewable energy systems in response to variable extreme weather conditions, highlighting the cost of resilience and demonstrating that power coupling with desalination can help mitigate the cost of achieving resilience.
{"title":"Integrating weather extremes and desalination flexibility to design a resilient concentrated solar power–photovoltaic–wind system with battery and thermal storage using TRNSYS","authors":"Farah Souayfane , Ricardo M. Lima , Asaad Katoua , Omar Knio","doi":"10.1016/j.enconman.2026.121064","DOIUrl":"10.1016/j.enconman.2026.121064","url":null,"abstract":"<div><div>Integrating large-scale renewable energy and storage systems is essential for sustainability in hot desert regions. However, resource variability and extreme weather pose operational and economic challenges, emphasizing the need for resilient systems. This study develops a TRNSYS simulation-based multi-objective optimization framework to design a resilient renewable energy system for a community in Saudi Arabia. Its novelty lies in the iterative incorporation of extreme weather derived from 25 years of historical weather data and the leveraging of sector coupling through the operational flexibility of a desalination plant. The optimization identifies optimal capacities for a system combining concentrated solar power, photovoltaic, and wind turbines, coupled with battery and thermal storage. The most economical off-grid configuration yields a life cycle cost of $1.46 billion and a levelized cost of energy of 0.1687 $/kWh with concentrated solar power supplying 96% of the energy (peak load of 86 MW and annual energy consumption of 505 GWh), which avoids 330,900 tonnes of <span><math><msub><mrow><mi>CO</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> emissions per year. This off-grid system, designed to withstand past extreme low solar radiation and high temperature days, requires additional generation and storage capacity, which increases the cost by 19%. Leveraging the desalination plant’s operational flexibility reduces the system’s cost by 2.7% while further enhancing system resilience. The framework provides a practical and adaptable method for designing resilient renewable energy systems in response to variable extreme weather conditions, highlighting the cost of resilience and demonstrating that power coupling with desalination can help mitigate the cost of achieving resilience.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"351 ","pages":"Article 121064"},"PeriodicalIF":10.9,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-23DOI: 10.1016/j.enconman.2026.121105
Oraib Dawaghreh, Sharaf K. Magableh, Caisheng Wang
Hydropower opportunities in many lake-rich regions remain largely unexploited. This is because long horizontal distances and modest elevation differences prohibit the feasibility of traditional pumped storage systems. The need for terrain-adaptive long-duration storage motivates the exploration of multi-stage, cascade-based designs capable of bridging these spatial constraints. This study investigates whether introducing intermediate reservoirs can transform geographically constrained lake systems into practical pumped hydro storage sites. An integrated modeling framework, including hydropower, solar, and wind simulation, geospatial analysis, and multi-objective evolutionary optimization, is applied using real meteorological and electrical load data from Mountain Lake, Michigan to determine optimal reservoir locations, storage capacities, and renewable generation sizing. Three cases were evaluated to assess the impact of different cascade configurations. Among them, the configuration with one intermediate reservoir achieves approximately 99.97 percent reliability with a levelized cost of energy between 0.133 and 0.165 USD per kilowatt-hour, while the two-reservoir arrangement demonstrates even lower cost and higher reliability. These findings demonstrate that a cascade configuration can significantly improve hydraulic performance and economic feasibility in low-slope terrains. The study concludes that multi-stage micro-pumped hydro architectures offer a geographically adaptable pathway for long-duration energy storage and can be deployed in regions where conventional two-reservoir systems are not viable.
{"title":"Cascade-pumped micro-hydro storage systems: A new design framework for efficient energy generation and storage in challenging topographies","authors":"Oraib Dawaghreh, Sharaf K. Magableh, Caisheng Wang","doi":"10.1016/j.enconman.2026.121105","DOIUrl":"10.1016/j.enconman.2026.121105","url":null,"abstract":"<div><div>Hydropower opportunities in many lake-rich regions remain largely unexploited. This is because long horizontal distances and modest elevation differences prohibit the feasibility of traditional pumped storage systems. The need for terrain-adaptive long-duration storage motivates the exploration of multi-stage, cascade-based designs capable of bridging these spatial constraints. This study investigates whether introducing intermediate reservoirs can transform geographically constrained lake systems into practical pumped hydro storage sites. An integrated modeling framework, including hydropower, solar, and wind simulation, geospatial analysis, and multi-objective evolutionary optimization, is applied using real meteorological and electrical load data from Mountain Lake, Michigan to determine optimal reservoir locations, storage capacities, and renewable generation sizing. Three cases were evaluated to assess the impact of different cascade configurations. Among them, the configuration with one intermediate reservoir achieves approximately 99.97 percent reliability with a levelized cost of energy between 0.133 and 0.165 USD per kilowatt-hour, while the two-reservoir arrangement demonstrates even lower cost and higher reliability. These findings demonstrate that a cascade configuration can significantly improve hydraulic performance and economic feasibility in low-slope terrains. The study concludes that multi-stage micro-pumped hydro architectures offer a geographically adaptable pathway for long-duration energy storage and can be deployed in regions where conventional two-reservoir systems are not viable.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"352 ","pages":"Article 121105"},"PeriodicalIF":10.9,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146033474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-23DOI: 10.1016/j.enconman.2026.121101
Mei Wang , Guoming Wen , Lang Liu , Shuangming Wang
As a strategic alternative to conventional oil and gas resources, tar-rich coal, coupled with its low-carbon in-situ extraction technologies, is rapidly emerging as a pivotal focus for sustainable energy development. This study presents an innovative tower type solar in-situ pyrolysis system for tar-rich coal (TS-IPS/TRC) to significantly reduce energy consumption in tar-rich coal extraction. A transient multiphysics model, integrating solar thermal conversion, nitrogen mediated heat transfer, and pyrolysis reaction kinetics, was constructed to investigate the influence of two critical operating parameters, nitrogen temperature and flow rate, on the dynamic behavior of the system. The results demonstrate that the heating rate during the initial pyrolysis stage is more responsive to variations in flow rate. Spatially, increasing the flow rate significantly enhance the heating effect near the injection well, while the effect gradually diminish in the regions farther away from the injection well. In accordance with system operational requirements, the optimal pyrolysis temperature was ascertained to be 983.15 K under a 24–hour cyclic operation strategy. In light of the temporal variations in solar energy, three operational approaches were subjected to rigorous evaluation. The results reveal that intermittent operation coupled with an elevated inlet temperature and a reduced flow rate of the heat transfer medium significantly enhances techno–economic performance. The intermittent heating mode effectively improves temperature uniformity within the pyrolysis zone. A 12–hour cyclic operation strategy is recommended. Increasing the inlet temperature from 933.15 K to 1033.15 K and decreasing the inlet flow velocity from 5 m/s to 2 m/s substantially increases the gas production rate by 61 %. The TS-IPS/TRC system can reduce power consumption by 61 % and decrease carbon emissions by 2.52 × 108 kg under the pyrolysis condition of 80 % of tar-rich coal. The proposed system demonstrates great potential in terms of energy conservation and emission reduction by pioneering a novel method for sustainable extraction of tar-rich coal in a low-carbon way.
{"title":"Dynamic modelling and characteristics analysis of a novel in situ tar-rich coal pyrolysis mining system driven by solar energy","authors":"Mei Wang , Guoming Wen , Lang Liu , Shuangming Wang","doi":"10.1016/j.enconman.2026.121101","DOIUrl":"10.1016/j.enconman.2026.121101","url":null,"abstract":"<div><div>As a strategic alternative to conventional oil and gas resources, tar-rich coal, coupled with its low-carbon in-situ extraction technologies, is rapidly emerging as a pivotal focus for sustainable energy development. This study presents an innovative tower type solar in-situ pyrolysis system for tar-rich coal (TS-IPS/TRC) to significantly reduce energy consumption in tar-rich coal extraction. A transient multiphysics model, integrating solar thermal conversion, nitrogen mediated heat transfer, and pyrolysis reaction kinetics, was constructed to investigate the influence of two critical operating parameters, nitrogen temperature and flow rate, on the dynamic behavior of the system. The results demonstrate that the heating rate during the initial pyrolysis stage is more responsive to variations in flow rate. Spatially, increasing the flow rate significantly enhance the heating effect near the injection well, while the effect gradually diminish in the regions farther away from the injection well. In accordance with system operational requirements, the optimal pyrolysis temperature was ascertained to be 983.15 K under a 24–hour cyclic operation strategy. In light of the temporal variations in solar energy, three operational approaches were subjected to rigorous evaluation. The results reveal that intermittent operation coupled with an elevated inlet temperature and a reduced flow rate of the heat transfer medium significantly enhances techno–economic performance. The intermittent heating mode effectively improves temperature uniformity within the pyrolysis zone. A 12–hour cyclic operation strategy is recommended. Increasing the inlet temperature from 933.15 K to 1033.15 K and decreasing the inlet flow velocity from 5 m/s to 2 m/s substantially increases the gas production rate by 61 %. The TS-IPS/TRC system can reduce power consumption by 61 % and decrease carbon emissions by 2.52 × 10<sup>8</sup> kg under the pyrolysis condition of 80 % of tar-rich coal. The proposed system demonstrates great potential in terms of energy conservation and emission reduction by pioneering a novel method for sustainable extraction of tar-rich coal in a low-carbon way.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"352 ","pages":"Article 121101"},"PeriodicalIF":10.9,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146033472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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