Energy Conversion and Management-X最新文献

{"title":"Transcritical CO2 refrigeration systems enhanced by ejector technology: state-of-the-art review","authors":"Enio Pedone Bandarra Filho ,&nbsp;Mouhammad El Hassan ,&nbsp;Nikolay Bukharin ,&nbsp;Zeeshan Rana ,&nbsp;Anas Sakout","doi":"10.1016/j.ecmx.2025.101500","DOIUrl":"10.1016/j.ecmx.2025.101500","url":null,"abstract":"<div><div>The demand for sustainable and environmentally benign refrigeration technologies has accelerated the adoption of carbon dioxide (CO₂) as a natural refrigerant. Despite its thermodynamic benefits and negligible global warming potential, the use of CO₂ in transcritical refrigeration cycles is constrained by significant inefficiencies, particularly related to throttling losses and high discharge pressures. Ejector technology has emerged as a potential addition mechanism that could enhance the overall cycle performance by recuperating the expansion work and distributing the pressure to optimal points. This review paper gives an in-depth and critical description of ejector-integrated transcritical CO₂ refrigeration systems. It explores the basics of ejectors, including ejector-based system configurations, their performance enhancement, control strategies, and industrial applications. Quantitative analyses from recent studies indicate that ejector integration can improve the system Coefficient of Performance (COP) by 10 to 25 % compared with conventional throttling cycles, while hybrid designs employing internal heat exchangers or parallel compression achieve gains up to 40 %. In addition, recent developments such as Computational Fluid Dynamics (CFD) and machine learning, are also discussed. The integration of CFD and ML frameworks has reduced prediction errors in the entrainment ratio and pressure lift to below 3%. Critical gaps are found in standardization, long-term reliability, and smart system integration. The review outlines preliminary directions including the establishment of unified testing protocols, the development of long-duration reliability studies, and the design of adaptive, sensor-integrated ejector systems for intelligent control. This review is cross-disciplinary and systematic in its scope to the critical role ejector technology has played in enhancing the development of high-efficiency and low-emission refrigeration technology.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"29 ","pages":"Article 101500"},"PeriodicalIF":7.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Techno-economic-environmental optimization of grid-connected hybrid microgrid integrating renewable and geothermal resources in Naama, Algeria","authors":"Riyadh Bouddou ,&nbsp;Abdallah Belabbes ,&nbsp;Nasreddine Bouchikhi ,&nbsp;Ayodeji Olalekan Salau ,&nbsp;Imane Haouam","doi":"10.1016/j.ecmx.2025.101512","DOIUrl":"10.1016/j.ecmx.2025.101512","url":null,"abstract":"<div><div>This paper presents a techno-economic and environmental optimization of a grid-connected hybrid microgrid (MG) designed to meet the combined electrical and thermal loads of Ain Ouarka and the neighboring town of Assela in Naama, Algeria, with surplus electricity exported to the Sonelgaz/SKTM national grid. The proposed MG integrates photovoltaic (PV) power generation, wind turbines, a geothermal cogeneration heat and power (CHP) unit, a diesel generator (DG), a boiler, lithium-ion battery storage, and a bidirectional converter. To ensure realistic operation, hourly real electrical and thermal load profiles were simulated over a full year. While HOMER Pro was used for component sizing and feasibility analysis, its standard dispatch strategies, load following (LF) and cycle charging (CC), rely on a rule-based search space that cannot simultaneously optimize electrical, thermal, and storage decisions in multi-energy systems. LF minimizes fuel use but cannot coordinate CHP thermal flows or battery SOC trajectories, whereas the CC dispatch strategy forces generators to operate at rated power even when this increases fuel consumption and operational costs, often trapping the optimization in locally optimal solutions. To address these limitations, a MATLAB Link–based Mixed-Integer Linear Programming (ML-MILP) controller was incorporated to perform single-objective hourly dispatch optimization aimed at minimizing instantaneous operating cost. HOMER then evaluates these optimized dispatch schedules and outcomes through long-term multi-objective optimization, minimizing the net present cost (NPC), levelized cost of energy (LCOE), and annual operating cost while maximizing renewable fraction (RF) and reducing emissions. Three system scenarios were examined. Scenario A, based solely on DG, grid electricity, and a boiler, resulted in an NPC of 17.6 M€, an LCOE of 0.373 €/kWh, and an operating cost of 942,420 €/year. Scenario B, a renewable–fossil hybrid without CHP, reduced costs to an NPC of 12.0 M€ and an LCOE of 0.254 €/kWh. The hybrid with complete integration, Scenario C, optimized with ML-MILP and involving geothermal-based CHP and thermal coupling, performed best with an NPC of 4.19 M€, LCOE of 0.0854 €/kWh, and a yearly operating cost of 408,050 €, which translated to a saving of 76.2 %, 72.9 %, and 56.7 % over Scenario A, with a further 27.5 % reduction in emissions of CO₂ and grid dependency reduced from 100 % to 28.6 %. Sensitivity analysis performed for fuel costs, total investment costs, and discount rate further validates the proposed approach applied to the optimal MG configuration. These results confirm that the incorporation of geothermal-based MGs with solar-wind generators, under MILP-based dispatch strategy, significantly enhances the sustainability, techno-economic performance, and operational robustness against uncertainties in hybrid MGs in semi-arid regions.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"29 ","pages":"Article 101512"},"PeriodicalIF":7.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Next-generation bio-based phase change materials for sustainable energy storage","authors":"Aman Yadav ,&nbsp;A.K. Pandey ,&nbsp;M. Samykano ,&nbsp;Yasir Ali Bhutto ,&nbsp;Zafar Said ,&nbsp;V.V. Tyagi","doi":"10.1016/j.ecmx.2025.101509","DOIUrl":"10.1016/j.ecmx.2025.101509","url":null,"abstract":"<div><div>Phase change materials are recognized for their capability to absorb and release significant amounts of heat during phase transformations and demonstrate compact uniqueness in thermal management applications. To establish sustainable energy storage techniques, phase change materials research has shifted its attention more and more towards bio-based phase change materials (BPCMs) as an alternative to traditional ones. This paper critically investigates a cutting-edge approach that harnesses the potential of BPCMs in thermal energy storage. Besides preparing BPCMs for thermal energy storage applications, the authors also outline innovative methods for material preparation. In addition, the present study thoroughly investigated thermophysical properties and surface morphology to ensure BPCM’s incorporation and optimal performance in thermal energy storage applications. The bio-waste-derived materials within the organic and bio-based PCM matrix resulted in variations in thermal conductivity and heat storage enthalpy. The results demonstrated that the composites exhibited a significant improvement in thermal properties and latent heat as compared to the base PCM. Further, the current obstacles and research gaps associated with BPCMs are comprehensively analyzed, laying the groundwork for further research. Moreover, an in-depth overview of the environmental impacts of BPCMs, their challenges, and future directions is comprehensively presented.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"29 ","pages":"Article 101509"},"PeriodicalIF":7.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of bidding strategies and design of value distribution mechanism for multi-type sources in power transaction","authors":"Yufa Qin,&nbsp;Xiaozhu Li,&nbsp;Longhao Chu,&nbsp;Chunya Yin","doi":"10.1016/j.ecmx.2026.101539","DOIUrl":"10.1016/j.ecmx.2026.101539","url":null,"abstract":"<div><div>This paper proposes a novel operational model enabling multi-type energy sources to participate in electricity markets, alongside a value distribution mechanism for flexible resources based on the Vickrey-Clarke-Groves (VCG) theory. These contributions address the critical challenges of insufficient flexible regulatory resources and inequitable value allocation among heterogeneous entities, thereby advancing the market-oriented reform of China’s power sector. The proposed three-level operational framework—comprising market, bidding, and dispatch layers—ensures coordinated decision-making, while the two-stage transaction mechanism incorporates social welfare-maximizing clearing and VCG-based settlement that precisely quantifies individual contributions. Simulation results demonstrate the effectiveness of the approach, showing that renewable energy plants require government subsidies when their bidding prices fall below 250 ¥/MWh, and that setting discharge subsidies for storage systems between 0.3–0.5 ¥/kWh fosters synergistic development with renewables. These findings offer valuable investment insights and policy recommendations for stakeholders.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"29 ","pages":"Article 101539"},"PeriodicalIF":7.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145976518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"DORES: a streamlined software for the design and operational planning of photovoltaic and storage systems in buildings and communities","authors":"Sofiane Kichou ,&nbsp;Nikolaos Skandalos","doi":"10.1016/j.ecmx.2026.101531","DOIUrl":"10.1016/j.ecmx.2026.101531","url":null,"abstract":"<div><div>Photovoltaics (PV) and electrical energy storage (EES) are key technologies for decarbonizing buildings and communities. Yet, planning integrated PV storage systems remains challenging due to solar variability, battery degradation, and economic uncertainty, and it requires simulating operational strategies to support informed design. Existing tools often address only part of this challenge, focusing on PV yield, economics, or microgrid optimization, without combining technical, economic, and environmental indicators across both building and community scales.</div><div>To address this gap, this paper introduces DORES (Design and Operational Planning of Renewable Energy Systems), a modular and user-friendly simulation tool for PV-storage integration. DORES models load profiles (measured or generated), PV systems, and batteries, and implements multiple energy management strategies, ranging from rule-based control to optimization-based methods that include battery wear costs. The tool automatically calculates key performance indicators (self-sufficiency, self-consumption, net present value, life cycle cost, and CO₂ savings) through a graphical interface developed in MATLAB. Validation against monitored data and a benchmark commercial tool (PV*SOL) shows high accuracy, with deviations in key indicators typically below 5%. In addition, DORES enables scenario testing at the community scale, supporting aggregated prosumer systems and shared storage assessment.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"29 ","pages":"Article 101531"},"PeriodicalIF":7.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nighttime thermoelectric power generation beyond 1 W/m2 achieved with concentrated photothermal storage","authors":"Abdulrahman M. Alajlan ,&nbsp;Saad Alrezihy ,&nbsp;Raid Almattairi ,&nbsp;Musaad Alotaibi ,&nbsp;Saichao Dang ,&nbsp;Qiaoqiang Gan","doi":"10.1016/j.ecmx.2026.101524","DOIUrl":"10.1016/j.ecmx.2026.101524","url":null,"abstract":"<div><div>Amid growing environmental challenges, autonomous sensing technologies have become essential tools for sustainable development by reducing dependence on traditional energy sources. Through an unconventional approach, we employ concentrated optical systems to enable nighttime power generation, extending the traditionally daytime-restricted use of solar energy. We achieve nighttime power generation at a density of 1.2 W/m² for the first time in thermoelectric systems, surpassing previous experimental limitations and setting a new benchmark in renewable energy technology. Furthermore, we demonstrate an autonomous sensing application that utilizes the generated nighttime thermoelectric power, highlighting the feasibility and promise of this approach for continuous, sustainable energy use.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"29 ","pages":"Article 101524"},"PeriodicalIF":7.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Global pathways for hybrid renewable energy systems: challenges, solutions, policy, and regulatory frameworks","authors":"Mahmudul Hasan,&nbsp;Nusrat Anjum Zarin,&nbsp;Mohammed Rezwan Ahmed,&nbsp;Omar Farrok","doi":"10.1016/j.ecmx.2026.101534","DOIUrl":"10.1016/j.ecmx.2026.101534","url":null,"abstract":"<div><div>Unprecedented economic and social shifts have been noticed globally as a result of global sustainability and the necessity of renewable energy to fight climate change. The best option for supplying green energy to address this global energy crisis is renewable energy sources. However, a single renewable energy source’s energy generation is unpredictable due to its intermittent nature. Hybrid renewable energy systems have attracted a lot of attention as a sustainable solution to the world’s growing energy needs while lowering environmental issues. This paper discusses many types of hybrid renewable energy system challenges and their solutions. This paper<!--> <!-->also discusses several alternatives and presents various effective approaches and analysis of global markets. The article presents various globally important policies, rules, and recommendations, as well as various IEEE, ISO, and IEC standards. Additionally this study presents the limitations of standards and rules in terms of their real-time execution. This study highlights the role of regulatory frameworks in enabling hybrid renewable energy system deployment and could benefit due to a depth analysis of policy effectiveness across different regions, discuss few barriers to policy implementation and also inclusion of some emerging policy instruments. A comparative performance metrics are provided for different hybrid renewable energy system models and also for different regions and case-based validation for lifecycle assessment.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"29 ","pages":"Article 101534"},"PeriodicalIF":7.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146037307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mitigation strategies for achieving carbon neutrality in the iron and steel industry—a case study of Sichuan, China","authors":"Chao Yue ,&nbsp;Jian Zang ,&nbsp;Guangyan He ,&nbsp;Bin Luo ,&nbsp;Xu Liu ,&nbsp;Lei Zhang ,&nbsp;Jun Wang","doi":"10.1016/j.ecmx.2025.101476","DOIUrl":"10.1016/j.ecmx.2025.101476","url":null,"abstract":"<div><div>Combating climate change calls for a low-carbon shift in China's steel industry. With strong renewable energy and widespread use of electric arc furnaces, Sichuan Province is expected to follow a distinct decarbonisation pathway. This study developed a Linear Bottom-up Technology and Energy Selection Model to simulate carbon emission trajectories of Sichuan's iron and steel industry through 2060. The model explicitly incorporates three steelmaking processes: blast furnace–basic oxygen furnace (BF–BOF), scrap-based electric arc furnace (Scrap–EAF), and hydrogen-based direct reduced iron coupled with EAF (DRI–EAF), under three crude steel demand scenarios peaking in 2024, 2027, and 2030. Results indicate that, by 2060, crude steel output will decline by 50%–65%, driving energy consumption down by 71%–80%. Consequently, CO₂ emissions will be reduced by over 90%, with emissions intensity falling to 0.3–0.4 tCO₂ per ton of crude steel. The energy mix shifts significantly, with hydrogen (30%), natural gas (22%), and electricity (19%) replacing coal and coke. BF–BOF will be phased out, while Scrap–EAF will account for 70% of production, and DRI–EAF will rise to 30%, being introduced between 2044 and 2048. Despite deep reductions, carbon capture, utilisation, and storage (CCUS) remains essential for neutralising residual emissions, capturing up to 38% of gross emissions removal. Cost analysis reveals that DRI–EAF requires either a decrease in hydrogen price or the implementation of a carbon pricing mechanism to achieve cost parity. These findings highlight that achieving a cost-effective low-carbon transition requires early demand peaking, the synergistic expansion of Scrap-EAF and DRI-EAF routes, limiting the use of hot metal, and the targeted deployment of CCUS.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"29 ","pages":"Article 101476"},"PeriodicalIF":7.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deep reinforcement learning‑based smart control of solar‑driven power cycle with thermal energy storage: A Los Angeles case study","authors":"Araz Emami,&nbsp;Ata Chitsaz,&nbsp;Amirali Nouri","doi":"10.1016/j.ecmx.2025.101478","DOIUrl":"10.1016/j.ecmx.2025.101478","url":null,"abstract":"<div><div>Solar-driven organic Rankine cycles (ORCs) require precise coordination of working fluid superheat, turbine inlet pressure, and net efficiency. Conventional single-loop control cannot effectively manage these tightly coupled objectives. This study introduces a deep deterministic policy gradient (DDPG) supervisory controller, trained using an 8760 hour global horizontal irradiance (GHI) dataset in a MATLAB-CoolProp environment. The reward function penalizes deviations in superheat, pressure, and efficiency. Over a full–year simulation, compared to a fixed-flow baseline, the Deep reinforcement learning-based (DRL-based) controller significantly dampened seasonal and transient variability: turbine inlet pressure stayed within around 4% of 2.5 MPa, superheat within nearly 0.2 K of a +10 K target, and efficiency between 20 and 30 percentage, improving the annual mean by 6 percentage points. Thermal energy storage exhibited stable, daily state-of-charge cycles, avoiding overcharge and depletion. A genetic algorithm (GA), applied exclusively to DRL controlled data, mapped the pressure, temperature and efficiency trade space. The Pareto front highlighted non-dominated optima near 2.55 MPa and 10.1-10.7 K, while dominated clusters corresponded to off–design pressure regimes. The integrated DRL-GA framework thus enables consistently optimal ORC operation under variable solar input, enhancing efficiency, stability, and component lifespan, and offering a deployable pathway for advanced renewable energy systems.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"29 ","pages":"Article 101478"},"PeriodicalIF":7.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on energy conservation of home appliances and equipment through questionnaires and measurement surveys in Japan","authors":"Mao Serikawa","doi":"10.1016/j.ecmx.2025.101488","DOIUrl":"10.1016/j.ecmx.2025.101488","url":null,"abstract":"<div><div>Climate change is a pressing issue that requires immediate action and calls for global efforts to conserve energy and reduce carbon dioxide (CO₂) emissions. A large proportion of energy consumption is attributed to houses, and the influence of home appliances is not negligible. However, regulations regarding energy conservation in houses apply only to attached facilities and do not consider related home appliances. Consequently, there is insufficient information on the actual situation regarding home appliances related to indoor environments, and measures to reduce power consumption are insufficient, leading to situations where occupants unintentionally use electricity. This study used questionnaires to assess the actual appliance and equipment usage conditions in Japanese houses. This study focuses on commonly overlooked appliances that consume a relatively large amount of electricity. Appliance usage varies widely depending on residential characteristics. For example, approximately 50% of households use home appliances or devices to dry clothes, mainly to avoid pollen and weather effects, and reduce the time and effort required for housework. Additionally, measurements and product surveys were conducted to determine the instantaneous power consumption and the amount of power consumed per use of home appliances. By integrating questionnaire and product survey results, the distribution of power consumption of electric heaters, bathroom dryers, and clothes dryers in Japanese houses was determined. These appliances were used frequently or for long periods in a certain percentage of houses and could reduce power consumption by switching to highly efficient devices.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"29 ","pages":"Article 101488"},"PeriodicalIF":7.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}