Energy Conversion and Management最新文献

{"title":"Local composition shift of refrigerant mixtures and its effect on cooling performance in a heat pump system","authors":"Yeonwoo Jeong ,&nbsp;Sangwook Lee ,&nbsp;Min Soo Kim","doi":"10.1016/j.enconman.2025.119809","DOIUrl":"10.1016/j.enconman.2025.119809","url":null,"abstract":"<div><div>Refrigerant mixtures provide variable thermodynamic properties through composition adjustment. However, when refrigerant mixtures are applied to heat pump systems, local composition shifts occur, resulting in different compositions within the system from the charge composition. This phenomenon is mainly caused by the velocity difference between liquid and vapor in the two-phase regions of heat exchangers. In this study, the local compositions in the evaporator are experimentally measured. The effects of system parameters on composition shift, such as charge composition, compressor speed, and water temperature in the evaporator, are analyzed using R32/R1234yf mixtures. Significant local composition shifts are observed with refrigerant mixtures exhibiting greater composition differences between the liquid and vapor phases. In addition, operating conditions of lower compressor speeds and lower water temperatures further intensify this phenomenon. With a compressor speed of 1000 rpm, the most considerable local composition shift of 9.0 %p occurs near the evaporator outlet. As a result of local composition shift, the average refrigerant temperature in the two-phase regions is elevated due to a higher proportion of R1234yf, degrading the heat transfer rate in the evaporator. To investigate its effect on cooling performance, a numerical model of the heat exchanger is established, and the cooling capacities with and without local composition shift are compared. Simulation results reveal cooling capacity decreases by up to 4.2 % due to local composition shift.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"333 ","pages":"Article 119809"},"PeriodicalIF":9.9,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143844538","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}

{"title":"Flexible power point tracking for photovoltaic systems based on the linear jump method","authors":"Fang Gao ,&nbsp;Zuchang Lin ,&nbsp;Linfei Yin ,&nbsp;Qing Gao","doi":"10.1016/j.enconman.2025.119805","DOIUrl":"10.1016/j.enconman.2025.119805","url":null,"abstract":"<div><div>With the rise of renewable energy, flexible photovoltaic (PV) power tracking control strategies are increasingly becoming a hot research topic. Existing constant power generation (CPG) methods often struggle to simultaneously meet the demands for rapid convergence, stable tracking, and algorithmic simplicity, particularly when environmental conditions change and reference power fluctuates. To address this issue, a linear jump method-based (LJM-B) flexible power point tracking (FPPT) algorithm is proposed in this work. This strategy determines the reference voltage corresponding to the reference power by calculating or estimating the linear slope of the P-V characteristic curve on the left of the maximum power point (MPP) of a single P-V peak. If the reference power is less than the available PV power, the system can directly jump to the reference power based on the calculated reference voltage. When the system’s maximum output power cannot meet the reference power, the algorithm significantly enhances the dynamic response speed by incorporating an initial jump step into the maximum power point tracking strategy. The proposed algorithm enables rapid adjustment of the system’s operating point through simple logic, facilitating accurate tracking of the reference power, whether in response to environmental changes or variations in the reference power. Simulation and experimental results demonstrate that the proposed algorithm significantly improves dynamic response and tracking performance compared to existing algorithms.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"333 ","pages":"Article 119805"},"PeriodicalIF":9.9,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143838925","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}

{"title":"Modeling and performance evaluation of a new multi-physical coupled system of photovoltaic-thermoelectric-interfacial evaporation","authors":"Yunfeng Qiu ,&nbsp;Meixiang Zhang ,&nbsp;Yahui Wang ,&nbsp;Xiao Guo ,&nbsp;Zhiguo Shi ,&nbsp;Haibo Wang ,&nbsp;Xiang Yu","doi":"10.1016/j.enconman.2025.119810","DOIUrl":"10.1016/j.enconman.2025.119810","url":null,"abstract":"<div><div>Interfacial evaporation, as an emerging seawater desalination technology, combines it with photovoltaic power generation technology and utilizes photovoltaic waste heat to drive interfacial evaporation, which is an effective measure for solving the problem of water and electricity shortage in off-grid island areas. Accurate calculations for different coupled forms of solar energy utilization systems are necessary to reduce the cost of preliminary experiments. In this paper, a coupled photo-electric-thermal-interfacial evaporation model is established based on photoelectric conversion model, heat transfer model, thermoelectric conversion model, and interfacial evaporation model, which is used to calculate the effects of meteorological parameters such as solar irradiance, ambient temperature, and ambient wind speed on the output performance of photovoltaic-interfacial evaporation and photovoltaic-thermoelectric-interfacial evaporation coupled systems, and experimental studies are carried out to validate the reliability of the model. The results show that the model has an average simulation error of 3.97 % for Photovoltaic module output power, 2.29 % for photovoltaic surface temperature, 6.11 % for thermoelectric generator output power, and 8.77 % for evaporation. Under the same conditions, the coupled photovoltaic-interfacial evaporation system has a lower net solar power generation efficiency than the coupled photovoltaic-thermoelectric-interfacial evaporation system but has a higher solar energy utilization and interfacial evaporation rate. As the emissivity of the photovoltaic surface increases, the net solar power generation efficiency of the system rises, but the interfacial evaporation rate and the utilization rate of solar energy of the system decrease. With the increase of output voltage of photovoltaic module, the net solar power generation efficiency and solar energy utilization rate of the system exhibit a trend of first increasing and then decreasing, while the interface evaporation rate of the system shows the change trend of first decreasing and then increasing.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"333 ","pages":"Article 119810"},"PeriodicalIF":9.9,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143844537","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}

{"title":"Sparks to synthesis: A roadmap to feasible ammonia production via plasma catalysis","authors":"Lance Kosca ,&nbsp;Mozah Almatrooshi ,&nbsp;Kaisar Ahmad ,&nbsp;Swati Singh ,&nbsp;Marko Gacesa ,&nbsp;Kyriaki Polychronopoulou","doi":"10.1016/j.enconman.2025.119802","DOIUrl":"10.1016/j.enconman.2025.119802","url":null,"abstract":"<div><div>Ammonia production is vital for global food security, supporting agriculture for approximately 70% of the world’s population. However, the conventional Haber-Bosch process is energy-intensive, fossil fuel-dependent, and responsible for 1–2% of global greenhouse gas emissions, limiting accessibility, particularly in developing nations. Plasma catalysis offers a promising alternative to electrifying decentralized, small-scale ammonia production with better integration into renewable energy systems. In addition to different methods of utilizing plasma for ammonia synthesis, this review examines recent kinetic and computational insights and laboratory-scale advancements in plasma catalysis allowing it to surpass conventional thermodynamic limitations and operate under significantly milder conditions than conventional Haber-Bosch with unconventional catalysts. It also discusses challenges in plasma catalysis related to energy efficiency, catalyst compatibility, and economic feasibility, stemming from the need to better understand nitrogen and hydrogen activity in nonthermal plasmas. These challenges provide key research directions and a roadmap towards feasible plasma catalysis for ammonia synthesis.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"333 ","pages":"Article 119802"},"PeriodicalIF":9.9,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143838781","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}

{"title":"Identification of industrial waste heat potential for district heating systems by pinch-based systematic graphical approach","authors":"Stanislav Boldyryev ,&nbsp;Goran Krajačić ,&nbsp;Endri Garafulić","doi":"10.1016/j.enconman.2025.119804","DOIUrl":"10.1016/j.enconman.2025.119804","url":null,"abstract":"<div><div>Recent global challenges necessitate shifting towards a more circular and efficient economic model. The European Union actively pursues this direction, emphasising energy security and diversification. Notably, industrial facilities and district heating systems are among the largest consumers of fossil fuels and contributors to pollution despite significant strides in renewable energy adoption. This paper explores the potential for energy collaboration between industrial sites and district heating networks, aiming to reduce heat loss and primary energy consumption. Using a systematic graphical approach based on pinch point analysis, energy efficiency and identifying the thermodynamically available heat from industrial processes for integration into district heating systems were investigated. This study examines the simultaneous optimisation of heat transfer in district heating systems alongside the cooling processes in industrial operations. Specifically, the fertiliser, polymer and cement industries were analysed to assess their compatibility with district heating networks. The findings reveal substantial potential for energy and emission reductions, with maximum recoverable heat from a light hydrocarbon distillation estimated at 28.85 GWh/y for low-temperature district heating, a notable 76.60 GWh/y from a nitric acid plant for high-temperature systems, and 186.48 GWh/y for high-temperature district heating. Corresponding emissions reductions are projected at 6.03 ktCO₂/y, 16.00 ktCO₂/y and 38.95 ktCO₂/y for the respective case studies. The insights from this research offer valuable contributions to both scientific knowledge and practical applications in enhancing energy efficiency and promoting partnerships between industry and district heating systems.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"333 ","pages":"Article 119804"},"PeriodicalIF":9.9,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143844540","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}

{"title":"A fidget spinner-inspired hybrid breeze wind energy harvester for self-sustainable wireless environmental monitoring system","authors":"Kumar Shrestha ,&nbsp;Akash Deo ,&nbsp;Aklesh Teli ,&nbsp;Trilochan Bhatta ,&nbsp;Jae Yeong Park","doi":"10.1016/j.enconman.2025.119795","DOIUrl":"10.1016/j.enconman.2025.119795","url":null,"abstract":"<div><div>Generating significant energy from inconsistent breeze winds poses a major challenge for wind-driven energy harvesters. To address this, a fidget spinner-inspired breeze wind energy harvester is newly proposed and developed to maximize energy capture from breeze winds. Leveraging the mechanics of a fidget spinner, the rotor can spin for approximately 25 s with single actuation, enabling continuous energy harvesting from inconsistent breeze winds. Similarly, the device incorporates custom-designed nuts and bolts to support magnetic load, enabling shaft to focus solely on rotating the rotor without the need to bear the magnet’s load. This optimization promotes effective energy harvesting from breezy winds and enhances energy generation. With six stacked magnets further boosting power output, a power density of 75.82 mW/m³ is achieved at wind speed of 3 m/s—the highest reported for such conditions. Additionally, the device includes a self-powered wind speed sensor (sensitivity 1.91 <span><math><mrow><mi>μ</mi><mi>A</mi><mo>/</mo><msup><mrow><mi>ms</mi></mrow><mrow><mo>-</mo><mn>1</mn></mrow></msup></mrow></math></span>), which generates a triboelectric signal using rabbit fur in combination with Styrene–Ethylene–Butylene–Styrene (SEBS). This sensor features interdigitated, flower-patterned, Laser-Induced Graphene (LIG) electrodes that are fabricated via a facile laser scribing technique and can easily transferred onto SEBS substrate without complex fabrication techniques or adhesives. As a proof of concept, the device is deployed in breezy environments like train stations and public parks for real-time environmental monitoring, demonstrating its potential to harvest substantial energy from breeze winds and feasibility for real-world applications.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"333 ","pages":"Article 119795"},"PeriodicalIF":9.9,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143838926","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}

{"title":"Ejector subcooling carbon dioxide combined heating and cooling system driven by waste heat: Energy, exergy, environment and economic evaluation","authors":"Baomin Dai ,&nbsp;Xiangjun Wang ,&nbsp;Shengchun Liu ,&nbsp;Mingxuan Wang ,&nbsp;Shandong Xie ,&nbsp;Tong Zhang ,&nbsp;Chenzi Li","doi":"10.1016/j.enconman.2025.119782","DOIUrl":"10.1016/j.enconman.2025.119782","url":null,"abstract":"<div><div>To address the annual demand for environmentally sustainable space conditioning in the building sector, a novel ejector subcooling transcritical carbon dioxide combined cooling and heating system driven waste heat is proposed. The energy, exergy, environment, economic analysis models are developed, and the energy efficiency is also optimized. Typical residential buildings located in 10 representative cities from 7 different climate zones are chosen as application scenarios. Besides the annual performance indicators, environmental and economic performance indicators are compared with 6 traditional solutions. The results show that in contrast to the baseline system, the discharge pressure can be decreased by 0.47 %∼4.74 %. In both heating and cooling mode, the coefficient of performance improvement ratio of the new proposed system using R1234ze(Z) and R1270 is the highest, reaching 20.65 % and 29.76 %, respectively. Cairo has the highest annual performance coefficient (APF) improvement ratio, with the APF of new system being 10.90 %∼21.05 % higher than the baseline system. APF of new proposed system is generally improved by 21.82 % to 42.81 % compared with the baseline system. In addition, in comparison with the coal-fired boilers and traditional air conditioning combination solution, the carbon emissions are reduced by 38.43 % throughout the lifecycle. In contrast to the direct electric heating and traditional air conditioning combination, the life cycle cost is decreased by 47.95 %. This study can serve as a theoretical reference for optimizing carbon dioxide combined heating and cooling system, as well as a new approach for year-round residential space heating and cooling.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"333 ","pages":"Article 119782"},"PeriodicalIF":9.9,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834393","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}

{"title":"Sensitivity study of operating conditions and liquid water transport behavior in an anion exchange membrane fuel cell aided by modeling and neutron radiography","authors":"Mrittunjoy Sarker ,&nbsp;Joy Marie Mora ,&nbsp;Felipe Mojica ,&nbsp;Ami C. Yang-Neyerlin ,&nbsp;Bryan Pivovar ,&nbsp;Daniel S. Hussey ,&nbsp;David L. Jacobson ,&nbsp;Jacob M. LaManna ,&nbsp;Po-Ya Abel Chuang","doi":"10.1016/j.enconman.2025.119750","DOIUrl":"10.1016/j.enconman.2025.119750","url":null,"abstract":"<div><div>Two types of anion exchange ionomers, powder and dispersion, are studied in this work. The gas diffusion electrode with the dispersion-type ionomer exhibits strong hydrophobicity, thus not enabling sufficient ionic exchange during the potassium hydroxide exchange process, which in turn exhibits very poor performance. Hence gas diffusion electrode prepared with the powder-type ionomer is used to study the sensitivity and effect of reactant concentration and operating conditions on anion exchange membrane fuel cell performance. The results indicate that the cell performance is most sensitive to relative humidity followed by hydrogen concentration. In contrast, oxygen is not a major performance limiting factor validated by oxygen reactant sensitivity analysis. Results from neutron imaging experiments demonstrate that active water transport from cathode to anode through electro-osmotic drag is very active, which results in flooding on the anode side, causing significant reduction of cell performance. The combined experimental and neutron results provide valuable insight into the water management strategies to improve the stability of fuel cell performance, which has a significant impact towards the development of anion exchange membrane fuel cell.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"333 ","pages":"Article 119750"},"PeriodicalIF":9.9,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834394","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}

{"title":"Heat collection enhancement of a thermoelectric generator based on micro heat pipe arrays","authors":"Chengyu Gu ,&nbsp;Cong Dong ,&nbsp;Qipeng Li ,&nbsp;Huaduo Gu ,&nbsp;Chenyu Zhu","doi":"10.1016/j.enconman.2025.119813","DOIUrl":"10.1016/j.enconman.2025.119813","url":null,"abstract":"<div><div>The implementation of micro heat pipe arrays (MHPAs) for enhancing heat collection at the thermoelectric generator’s hot end is investigated, with a comparative analysis against conventional copper and aluminum heat collection plates. The influence of key structural parameters, including length, inclination angle, and bending angle of MHPAs, is systematically quantified. A novel composite quantification factor, termed the “multidimensional structural parameter index”, was formulated to characterize the synergistic effects of structural parameters. The results demonstrate that MHPAs exhibit remarkable thermoelectric characteristics, achieving 352 % and 635 % greater average temperature differences compared to copper and aluminum heat collection plates, respectively. At a 50 % immersion depth, heat collection capacities of 85.12 %, 84.55 %, and 84.34 % are consistently achieved for lengths of 200 mm, 250 mm, and 300 mm, respectively. The sensitivity of thermoelectric characteristics to the bending angle varies with inclination angle and length, with the 250 mm length scheme at a 50° inclination angle exhibiting the maximum sensitivity. A constant inclination angle, coupled with a variable bending angle, determines the power output dynamics, with a 130° bending angle scheme demonstrating a 47.27 % increase in power output. These findings provide essential guidance for the engineering applications of thermoelectric generator systems.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"333 ","pages":"Article 119813"},"PeriodicalIF":9.9,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143838724","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}

{"title":"Harnessing the full solar spectrum in CPV/T systems by combining selective liquid filters and phase change materials","authors":"ELSaeed Saad ELSihy ,&nbsp;Mostafa M. Abd El-Samie ,&nbsp;Mohamed I. Hassan Ali ,&nbsp;Zuyuan Wang","doi":"10.1016/j.enconman.2025.119799","DOIUrl":"10.1016/j.enconman.2025.119799","url":null,"abstract":"<div><div>Effectively utilizing the solar spectrum in concentrated photovoltaic/thermal (CPV/T) systems remains challenging due to significant heat losses and insufficient thermal decoupling between PV cells and thermal absorbers. This study reports a novel bypass CPV/T design employing water as both a spectral liquid filter (SLF) and active coolant, paired with phase change materials (PCMs) for passive cooling. Through detailed three-dimensional computational fluid dynamics simulations, the overall performance of the hybrid CPV/T-PCM/SBS (spectral beam splitting) system is explored, and the key parameters to maximize the energy productivity and economic feasibility are determined. While a thicker SLF improves the heat recovery, the produced electricity is sacrificed owing to the reduced light transmission in the PV waveband. Conversely, a thinner SLF increases the electrical power but causes higher PV cell temperatures and reduced thermal gains. Balancing the SLF thickness and concentrating ratio (<em>CR</em>) is critical to enhance the system efficiency. For the designed module, the optimal design features an SLF thickness of 6.045 mm, a flow rate of 0.105 kg/s, and a PCM layer thickness of 28.266 mm at <em>CR</em> ∼ 20. Optimizing the optical characteristics of the SLF and the thermophysical properties of the PCM allows for maximizing the productivity of the CPV/T-PCM/SBS system, making it a promising solution for high concentrated solar applications with efficient energy generation and thermal management.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"333 ","pages":"Article 119799"},"PeriodicalIF":9.9,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143830214","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}