Energy Conversion and Management最新文献

Experimental study on temperature characteristics and output performance of PEMFCs based on HFE-7100 boiling cooling

IF 9.9 1区工程技术 Q1 ENERGY & FUELS

Energy Conversion and Management

Pub Date : 2025-04-27 DOI: 10.1016/j.enconman.2025.119838

Zhihao Sun , Yanyan Li , Guanchen Liao , Xianglong Luo , Yingzong Liang , Jianyong Chen , Zhi Yang , Ying Chen

Proton exchange membrane fuel cells (PEMFCs) are a promising clean energy technology; however, effective thermal management remains a critical challenge, particularly at high power densities, where temperature imbalances can severely impact stack performance and longevity. Boiling cooling, which utilizes the phase change of the coolant, presents a potential solution to enhance thermal management in PEMFCs. Despite its promise, its practical application in fuel cell stacks has not been fully explored. This study aims to address this gap by developing a performance testing platform to assess the temperature characteristics and output performance of PEMFCs under boiling cooling conditions. Temperature uniformity was evaluated using the wall temperature difference (T_d) and the temperature uniformity index (TUI), with a focus on the effects of coolant inlet temperature and mass flux. A univariate experimental design was employed to systematically investigate the impact of five critical operational parameters—coolant inlet temperature, mass flux, hydrogen flow rate, humidifier temperature, and exhaust back pressure—on PEMFC performance. The results demonstrate that boiling cooling significantly improves temperature uniformity, with TUI improvements of approximately 47.69 % for Cell 1 and 58.58 % for Cell 3, especially at high current densities. In comparison to single-phase cooling, boiling cooling exhibited superior thermal management capacity, maintaining stable output at higher power densities. Furthermore, the stack’s power output was improved by 9.04 % under boiling cooling. The optimization of operational parameters, such as hydrogen flow rate, humidifier temperature, and exhaust back pressure, was shown to enhance reaction efficiency and mitigate issues such as membrane dehydration and flooding. These findings validate the effectiveness of boiling cooling as a robust thermal management solution for PEMFCs, highlighting the importance of parameter optimization for further improving fuel cell performance and reliability.

{"title":"Experimental study on temperature characteristics and output performance of PEMFCs based on HFE-7100 boiling cooling","authors":"Zhihao Sun , Yanyan Li , Guanchen Liao , Xianglong Luo , Yingzong Liang , Jianyong Chen , Zhi Yang , Ying Chen","doi":"10.1016/j.enconman.2025.119838","DOIUrl":"10.1016/j.enconman.2025.119838","url":null,"abstract":"<div><div>Proton exchange membrane fuel cells (PEMFCs) are a promising clean energy technology; however, effective thermal management remains a critical challenge, particularly at high power densities, where temperature imbalances can severely impact stack performance and longevity. Boiling cooling, which utilizes the phase change of the coolant, presents a potential solution to enhance thermal management in PEMFCs. Despite its promise, its practical application in fuel cell stacks has not been fully explored. This study aims to address this gap by developing a performance testing platform to assess the temperature characteristics and output performance of PEMFCs under boiling cooling conditions. Temperature uniformity was evaluated using the wall temperature difference (<em>T<sub>d</sub></em>) and the temperature uniformity index (<em>TUI</em>), with a focus on the effects of coolant inlet temperature and mass flux. A univariate experimental design was employed to systematically investigate the impact of five critical operational parameters—coolant inlet temperature, mass flux, hydrogen flow rate, humidifier temperature, and exhaust back pressure—on PEMFC performance. The results demonstrate that boiling cooling significantly improves temperature uniformity, with <em>TUI</em> improvements of approximately 47.69 % for Cell 1 and 58.58 % for Cell 3, especially at high current densities. In comparison to single-phase cooling, boiling cooling exhibited superior thermal management capacity, maintaining stable output at higher power densities. Furthermore, the stack’s power output was improved by 9.04 % under boiling cooling. The optimization of operational parameters, such as hydrogen flow rate, humidifier temperature, and exhaust back pressure, was shown to enhance reaction efficiency and mitigate issues such as membrane dehydration and flooding. These findings validate the effectiveness of boiling cooling as a robust thermal management solution for PEMFCs, highlighting the importance of parameter optimization for further improving fuel cell performance and reliability.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"334 ","pages":"Article 119838"},"PeriodicalIF":9.9,"publicationDate":"2025-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143876849","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}

引用次数: 0

Performance assessment of two-step solar thermochemical fuel production systems with a transient multi-scale model

IF 9.9 1区工程技术 Q1 ENERGY & FUELS

Energy Conversion and Management

Pub Date : 2025-04-27 DOI: 10.1016/j.enconman.2025.119821

Lei Zhao , Da Xu , Shuai Deng , Meng Lin

This study investigates the performance of solar thermochical hydrogen production systems across a range of operational conditions and material candidates. The objective is to guide the design of efficient reactor and enable rapid screening of promising redox materials. A multi-scale modeling framework is developed by integrating a system-level model, which includes heat exchangers and gas separation, with a detailed multi-physical model for a generic packed bed reactor. The transient multi-physical model incorporates fluid flow, heat transfer, mass transfer, and thermochemical reactions to enable more accurate performance predictions. Results show that solar irradiation direction perpendicular to the fluid flow minimizes temperature gradients, achieving a temperature difference as low as 49 K. A porosity of 0.75 results in the highest

η_{STF}

and improving gas-phase heat recovery efficiency from 0.75 to 0.95 leads to an 18.9 % increase in

η_{STF}

. Under identical conditions, CeO₂ exhibited the highest hydrogen production at 3.8 mL/g, while Zr₁₅Ce_0.85O₂ produced 3.0 mL/g and La_0.6Ca_0.4Mn_0.6Al_0.4O₃ produced 1.3 mL/g due to slower oxidation kinetics. The transient model also predicts the reactor’s performance evolution over a 30-year operational cycle, considering optical and material degradation, enabling the assessment of long-term reliability and guiding future system designs. This study provides a comprehensive framework for reactor optimization, advancing the practical implementation and scalability of solar thermochemical fuel production technologies.

{"title":"Performance assessment of two-step solar thermochemical fuel production systems with a transient multi-scale model","authors":"Lei Zhao , Da Xu , Shuai Deng , Meng Lin","doi":"10.1016/j.enconman.2025.119821","DOIUrl":"10.1016/j.enconman.2025.119821","url":null,"abstract":"<div><div>This study investigates the performance of solar thermochical hydrogen production systems across a range of operational conditions and material candidates. The objective is to guide the design of efficient reactor and enable rapid screening of promising redox materials. A multi-scale modeling framework is developed by integrating a system-level model, which includes heat exchangers and gas separation, with a detailed multi-physical model for a generic packed bed reactor. The transient multi-physical model incorporates fluid flow, heat transfer, mass transfer, and thermochemical reactions to enable more accurate performance predictions. Results show that solar irradiation direction perpendicular to the fluid flow minimizes temperature gradients, achieving a temperature difference as low as 49 K. A porosity of 0.75 results in the highest  <!-->This study provides a comprehensive framework for reactor optimization, advancing the practical implementation and scalability of solar thermochemical fuel production technologies.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"334 ","pages":"Article 119821"},"PeriodicalIF":9.9,"publicationDate":"2025-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143876998","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}

引用次数: 0

Optimizing wind power utilization through integrated thermoelectric peak shaving

IF 9.9 1区工程技术 Q1 ENERGY & FUELS

Energy Conversion and Management

Pub Date : 2025-04-26 DOI: 10.1016/j.enconman.2025.119828

Haichao Wang , Jianbo Han , Tianyu Wang , Zhiwen Luo , Risto Lahdelma , Katja Granlund , Esa Teppo

The integration of wind power into energy systems is a critical global challenge in the context of limited peak shaving capacity of cogeneration units, observed in many regions with high wind energy potential. This study explores thermoelectric decoupling strategies to enhance wind power utilization and improve system efficiency. Four integrated thermoelectric peak shaving schemes are investigated, including electric boiler, electric heat pump, absorption heat pump, and mechanical heat pump, each integrated with thermal energy storage. A mathematical model was developed and validated using data from a combined heat and power plant in Jilin Province, China, demonstrating its scalability and applicability. The results indicate that the mechanical heat pump and electric heat pump schemes achieved the highest net incomes, with exergic efficiencies exceeding 65 %. The electric boiler scheme achieved the highest wind power utilization, reducing the wind curtailment rate to 0.1 %. All schemes contributed to significant coal savings, with the mechanical heat pump reducing standard coal consumption by 16.91 kg/MWh of electricity and 1.22 kg/GJ of heat. Furthermore, the schemes demonstrated substantial carbon emission reductions and improvements in overall energy efficiency. These findings provide more insights into enhancing the operational flexibility of combined heat and power systems and integrating renewable energy sources, offering a scalable solution for regions seeking to transition to low-carbon energy systems.

{"title":"Optimizing wind power utilization through integrated thermoelectric peak shaving","authors":"Haichao Wang , Jianbo Han , Tianyu Wang , Zhiwen Luo , Risto Lahdelma , Katja Granlund , Esa Teppo","doi":"10.1016/j.enconman.2025.119828","DOIUrl":"10.1016/j.enconman.2025.119828","url":null,"abstract":"<div><div>The integration of wind power into energy systems is a critical global challenge in the context of limited peak shaving capacity of cogeneration units, observed in many regions with high wind energy potential. This study explores thermoelectric decoupling strategies to enhance wind power utilization and improve system efficiency. Four integrated thermoelectric peak shaving schemes are investigated, including electric boiler, electric heat pump, absorption heat pump, and mechanical heat pump, each integrated with thermal energy storage. A mathematical model was developed and validated using data from a combined heat and power plant in Jilin Province, China, demonstrating its scalability and applicability. The results indicate that the mechanical heat pump and electric heat pump schemes achieved the highest net incomes, with exergic efficiencies exceeding 65 %. The electric boiler scheme achieved the highest wind power utilization, reducing the wind curtailment rate to 0.1 %. All schemes contributed to significant coal savings, with the mechanical heat pump reducing standard coal consumption by 16.91 kg/MWh of electricity and 1.22 kg/GJ of heat. Furthermore, the schemes demonstrated substantial carbon emission reductions and improvements in overall energy efficiency. These findings provide more insights into enhancing the operational flexibility of combined heat and power systems and integrating renewable energy sources, offering a scalable solution for regions seeking to transition to low-carbon energy systems.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"333 ","pages":"Article 119828"},"PeriodicalIF":9.9,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143877374","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}

引用次数: 0

Cost-effective optimization for charging/discharging cycles of thermal energy ice storages in transcritical R744 supermarket refrigeration systems

IF 9.9 1区工程技术 Q1 ENERGY & FUELS

Energy Conversion and Management

Pub Date : 2025-04-26 DOI: 10.1016/j.enconman.2025.119790

Yousef Sheikh Kilo , Roozbeh Izadi-Zamanabadi , Hossein Ramezani , Paride Gullo , Shouvik Chaudhuri

Due to the low critical temperature of R744, supermarket refrigeration systems using this working fluid widely operate in transcritical operating conditions, causing severe penalizations on their energy efficiency. On the one hand, this study explored the economic benefits from integrating a thermal energy ice storage to cool down the R744 leaving the condenser/gas cooler to address the aforementioned performance disadvantages. On the other hand, the literature review brought to light the lack of an algorithm to cost-effectively and dynamically optimize the charging and discharging cycles of thermal energy ice storages in transcritical R744 refrigeration systems, thus limiting their spread in supermarkets. Therefore, an innovative algorithm tailored to different climate conditions was developed in this study with the goal of minimizing yearly electricity expenses by accounting for supermarket refrigeration demand, ambient temperature, and electricity price. The novel optimization method incorporated constraints that reflected realistic requirements for the thermal energy ice storage’s expected capacity, its selected compressor, and desired level of maximum charge/discharge rate. Simulations performed in Seville (Spain), Athens (Greece) and New Delhi (India) revealed a reduction in the annual electricity bill of the supermarket by 6.9 %, 5.7 % and 12.5 % compared to the case without thermal energy ice storage thanks to the new optimization strategy, respectively. The results obtained showcase the efficacy of the innovative algorithm, suggesting a promising approach to improve the energy efficiency and cost-effectiveness in the commercial refrigeration industry.

{"title":"Cost-effective optimization for charging/discharging cycles of thermal energy ice storages in transcritical R744 supermarket refrigeration systems","authors":"Yousef Sheikh Kilo , Roozbeh Izadi-Zamanabadi , Hossein Ramezani , Paride Gullo , Shouvik Chaudhuri","doi":"10.1016/j.enconman.2025.119790","DOIUrl":"10.1016/j.enconman.2025.119790","url":null,"abstract":"<div><div>Due to the low critical temperature of R744, supermarket refrigeration systems using this working fluid widely operate in transcritical operating conditions, causing severe penalizations on their energy efficiency. On the one hand, this study explored the economic benefits from integrating a thermal energy ice storage to cool down the R744 leaving the condenser/gas cooler to address the aforementioned performance disadvantages. On the other hand, the literature review brought to light the lack of an algorithm to cost-effectively and dynamically optimize the charging and discharging cycles of thermal energy ice storages in transcritical R744 refrigeration systems, thus limiting their spread in supermarkets. Therefore, an innovative algorithm tailored to different climate conditions was developed in this study with the goal of minimizing yearly electricity expenses by accounting for supermarket refrigeration demand, ambient temperature, and electricity price. The novel optimization method incorporated constraints that reflected realistic requirements for the thermal energy ice storage’s expected capacity, its selected compressor, and desired level of maximum charge/discharge rate. Simulations performed in Seville (Spain), Athens (Greece) and New Delhi (India) revealed a reduction in the annual electricity bill of the supermarket by 6.9 %, 5.7 % and 12.5 % compared to the case without thermal energy ice storage thanks to the new optimization strategy, respectively. The results obtained showcase the efficacy of the innovative algorithm, suggesting a promising approach to improve the energy efficiency and cost-effectiveness in the commercial refrigeration industry.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"334 ","pages":"Article 119790"},"PeriodicalIF":9.9,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143874990","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}

引用次数: 0

Aerodynamic reconstruction of wind turbines using terrestrial laser scanning: Methodology, validation, and error analysis

IF 9.9 1区工程技术 Q1 ENERGY & FUELS

Energy Conversion and Management

Pub Date : 2025-04-26 DOI: 10.1016/j.enconman.2025.119792

Zhen Xie , Zhongwei Lin , Qinlin Cai , Zhenyu Chen

Aerodynamic performance analysis is essential for improving wind turbine efficiency and reliability, yet it is often constrained by the lack of aerodynamic models, either due to commercial confidentiality or the legacy turbine types. This study proposes a novel method for aerodynamic reconstruction of wind turbines using Terrestrial Laser Scanning (TLS). The method allows for efficiently capturing turbine geometry and aerodynamic properties without requiring blade disassembly. The specific procedures, including TLS-based data acquisition, data preprocessing, and blade parameterization, are outlined systematically to demonstrate the complete framework. A field implementation on a 2 MW commercial wind turbine proved its effectiveness, with validation against historical data and manufacturer-supplied performance curves showing strong consistency. Challenges such as blade twist variations and wind speed measurement inaccuracies are analyzed as potential error sources, and strategies for enhancing precision and reliability are provided. The proposed method offers a competitive, engineering-oriented solution for wind turbine aerodynamic reconstruction, laying a foundation for enhanced turbine design, operational efficiency, and long-term performance optimization.

{"title":"Aerodynamic reconstruction of wind turbines using terrestrial laser scanning: Methodology, validation, and error analysis","authors":"Zhen Xie , Zhongwei Lin , Qinlin Cai , Zhenyu Chen","doi":"10.1016/j.enconman.2025.119792","DOIUrl":"10.1016/j.enconman.2025.119792","url":null,"abstract":"<div><div>Aerodynamic performance analysis is essential for improving wind turbine efficiency and reliability, yet it is often constrained by the lack of aerodynamic models, either due to commercial confidentiality or the legacy turbine types. This study proposes a novel method for aerodynamic reconstruction of wind turbines using Terrestrial Laser Scanning (TLS). The method allows for efficiently capturing turbine geometry and aerodynamic properties without requiring blade disassembly. The specific procedures, including TLS-based data acquisition, data preprocessing, and blade parameterization, are outlined systematically to demonstrate the complete framework. A field implementation on a 2 MW commercial wind turbine proved its effectiveness, with validation against historical data and manufacturer-supplied performance curves showing strong consistency. Challenges such as blade twist variations and wind speed measurement inaccuracies are analyzed as potential error sources, and strategies for enhancing precision and reliability are provided. The proposed method offers a competitive, engineering-oriented solution for wind turbine aerodynamic reconstruction, laying a foundation for enhanced turbine design, operational efficiency, and long-term performance optimization.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"334 ","pages":"Article 119792"},"PeriodicalIF":9.9,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143874991","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}

引用次数: 0

Approximate analytical solutions for solar cell current-voltage characteristics: A four-diode model with two novel approaches

IF 9.9 1区工程技术 Q1 ENERGY & FUELS

Energy Conversion and Management

Pub Date : 2025-04-26 DOI: 10.1016/j.enconman.2025.119835

Martin P Ćalasan , Snežana Vujošević , Ivana Radonjić Mitić

In the available literature, there are three basic solar cell models—the Single Diode Model (SDM), Double Diode Model (DDM), and Triple Diode Model (TDM). Recently, the Four-Diode Model (FDM) has been introduced to further improve the representation of recombination and loss processes in solar cells. However, this model has not been analyzed from the perspective of analytical modeling of the current–voltage (I-V) characteristics. In this study, two approximate analytical models are proposed to describe the I-V characteristics of solar cells using the Lambert W function. To ensure accurate and efficient parameter estimation, advanced optimization techniques have been applied. A comprehensive evaluation of the proposed modeling approaches and the employed optimization methods demonstrates their effectiveness, leading to significant improvements in parameter accuracy, with enhancements exceeding 50% in certain cases. Furthermore, the proposed solutions have been tested on solar cells based on different fabrication technologies and under extreme operating conditions, confirming their robustness and broad applicability. Additionally, to demonstrate the accuracy and efficiency of the proposed approximate solutions of the FDM model, experimental results measured on solar panels installed on the building of the Faculty of Sciences and Mathematics in Niš, Serbia, were also analyzed. These findings contribute to the advancement of analytical solar cell modeling, offering more precise and computationally efficient methods for both research and practical applications.

{"title":"Approximate analytical solutions for solar cell current-voltage characteristics: A four-diode model with two novel approaches","authors":"Martin P Ćalasan , Snežana Vujošević , Ivana Radonjić Mitić","doi":"10.1016/j.enconman.2025.119835","DOIUrl":"10.1016/j.enconman.2025.119835","url":null,"abstract":"<div><div>In the available literature, there are three basic solar cell models—the Single Diode Model (SDM), Double Diode Model (DDM), and Triple Diode Model (TDM). Recently, the Four-Diode Model (FDM) has been introduced to further improve the representation of recombination and loss processes in solar cells. However, this model has not been analyzed from the perspective of analytical modeling of the current–voltage (I-V) characteristics. In this study, two approximate analytical models are proposed to describe the I-V characteristics of solar cells using the Lambert W function. To ensure accurate and efficient parameter estimation, advanced optimization techniques have been applied. A comprehensive evaluation of the proposed modeling approaches and the employed optimization methods demonstrates their effectiveness, leading to significant improvements in parameter accuracy, with enhancements exceeding 50% in certain cases. Furthermore, the proposed solutions have been tested on solar cells based on different fabrication technologies and under extreme operating conditions, confirming their robustness and broad applicability. Additionally, to demonstrate the accuracy and efficiency of the proposed approximate solutions of the FDM model, experimental results measured on solar panels installed on the building of the Faculty of Sciences and Mathematics in Niš, Serbia, were also analyzed. These findings contribute to the advancement of analytical solar cell modeling, offering more precise and computationally efficient methods for both research and practical applications.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"334 ","pages":"Article 119835"},"PeriodicalIF":9.9,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143874941","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}

引用次数: 0

Feasibility study on electrochemical compressor utilizing water-hydrogen heat pump system

IF 9.9 1区工程技术 Q1 ENERGY & FUELS

Energy Conversion and Management

Pub Date : 2025-04-25 DOI: 10.1016/j.enconman.2025.119832

Youngki Kim , Chanho Chu , Taeyoung Beom , Sihyung Park , Bonhyo Gu , Seonyeob Kim , Sangwon Kim , Dong Kyu Kim

Heat pump systems offer significant potential for achieving high efficiency and have gained attention as an environmentally friendly technology. However, traditional compressors used in heat pumps face issues such as low efficiency, noise, and oil contamination. Electrochemical compressors offer a promising alternative to address these challenges, but research on heat pump systems utilizing electrochemical compressors remains limited. A high-pressure electrochemical compressor is designed, and both experimental and numerical analyses are conducted to analyze the operational characteristics under varying conditions. The results show that increasing power consumption leads to a higher mass flux of refrigerant, driven primarily by electro-osmotic drag. Additionally, increasing the mixing ratio from 24% to 30% results in a threefold increase in mass flux, attributed to enhanced membrane conductivity. Higher operating temperatures also significantly improve mass flux by reducing back diffusion. A performance map is developed to analyze the comprehensive performance characteristics of an electrochemical compressor. The analysis reveals that the efficiency of the compressor exceeds 50% at pressure ratios below 3, with particularly high efficiency observed in regions of low mass flux. These findings demonstrate the potential of electrochemical compressors to be used in heat pump system to improve the overall efficiency.

{"title":"Feasibility study on electrochemical compressor utilizing water-hydrogen heat pump system","authors":"Youngki Kim , Chanho Chu , Taeyoung Beom , Sihyung Park , Bonhyo Gu , Seonyeob Kim , Sangwon Kim , Dong Kyu Kim","doi":"10.1016/j.enconman.2025.119832","DOIUrl":"10.1016/j.enconman.2025.119832","url":null,"abstract":"<div><div>Heat pump systems offer significant potential for achieving high efficiency and have gained attention as an environmentally friendly technology. However, traditional compressors used in heat pumps face issues such as low efficiency, noise, and oil contamination. Electrochemical compressors offer a promising alternative to address these challenges, but research on heat pump systems utilizing electrochemical compressors remains limited. A high-pressure electrochemical compressor is designed, and both experimental and numerical analyses are conducted to analyze the operational characteristics under varying conditions. The results show that increasing power consumption leads to a higher mass flux of refrigerant, driven primarily by electro-osmotic drag. Additionally, increasing the mixing ratio from 24% to 30% results in a threefold increase in mass flux, attributed to enhanced membrane conductivity. Higher operating temperatures also significantly improve mass flux by reducing back diffusion. A performance map is developed to analyze the comprehensive performance characteristics of an electrochemical compressor. The analysis reveals that the efficiency of the compressor exceeds 50% at pressure ratios below 3, with particularly high efficiency observed in regions of low mass flux. These findings demonstrate the potential of electrochemical compressors to be used in heat pump system to improve the overall efficiency.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"334 ","pages":"Article 119832"},"PeriodicalIF":9.9,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869000","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}

引用次数: 0

Understanding the role of thermo-diffusive instabilities in hydrogen combustion for lean-burn spark-ignition engine operation

IF 9.9 1区工程技术 Q1 ENERGY & FUELS

Energy Conversion and Management

Pub Date : 2025-04-24 DOI: 10.1016/j.enconman.2025.119801

R. Novella, J. Gomez-Soriano, D. González-Domínguez, O. Olaciregui

This study introduces a novel numerical approach for modeling hydrogen combustion in lean-burn spark-ignition engines, incorporating thermo-diffusive instabilities (TDI) within a CFD URANS-based framework. The study focuses on identifying potential sources of prediction errors and validating the robustness of the methodology under different operating conditions. The results indicate that the method performs well within moderate dilution ratios, but its accuracy decreases at higher dilution levels (e.g.,

λ

= 3.4), where predictions become less reliable. Analysis of the turbulent flame regime reveals that the coupling between TDI and turbulence is not adequately reproduced at high dilution ratios, suggesting that certain phenomena are not captured by the model. Including TDI effects significantly improves the model ability to replicate experimental trends, with a substantial increase in predictive accuracy. However, some limitations remain in predicting hydrogen combustion under realistic internal combustion engine (ICE) operating conditions, highlighting the need for further research to refine the model. The results have significant implications for the development of more efficient and environmentally friendly engines, as hydrogen is considered a promising fuel for reducing greenhouse gas and nitrogen oxide emissions in the transportation sector.

{"title":"Understanding the role of thermo-diffusive instabilities in hydrogen combustion for lean-burn spark-ignition engine operation","authors":"R. Novella, J. Gomez-Soriano, D. González-Domínguez, O. Olaciregui","doi":"10.1016/j.enconman.2025.119801","DOIUrl":"10.1016/j.enconman.2025.119801","url":null,"abstract":"<div><div>This study introduces a novel numerical approach for modeling hydrogen combustion in lean-burn spark-ignition engines, incorporating thermo-diffusive instabilities (TDI) within a CFD URANS-based framework. The study focuses on identifying potential sources of prediction errors and validating the robustness of the methodology under different operating conditions. The results indicate that the method performs well within moderate dilution ratios, but its accuracy decreases at higher dilution levels (e.g., <span><math><mi>λ</mi></math></span> = 3.4), where predictions become less reliable. Analysis of the turbulent flame regime reveals that the coupling between TDI and turbulence is not adequately reproduced at high dilution ratios, suggesting that certain phenomena are not captured by the model. Including TDI effects significantly improves the model ability to replicate experimental trends, with a substantial increase in predictive accuracy. However, some limitations remain in predicting hydrogen combustion under realistic internal combustion engine (ICE) operating conditions, highlighting the need for further research to refine the model. The results have significant implications for the development of more efficient and environmentally friendly engines, as hydrogen is considered a promising fuel for reducing greenhouse gas and nitrogen oxide emissions in the transportation sector.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"334 ","pages":"Article 119801"},"PeriodicalIF":9.9,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869001","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}

引用次数: 0

Broadband wave conversion by a “Pan Flute”-type multi-oscillating-water-column (M−OWC) breakwater system 潘笛 "型多振荡水柱（M-OWC）防波堤系统的宽带波浪转换功能

IF 9.9 1区工程技术 Q1 ENERGY & FUELS

Energy Conversion and Management

Pub Date : 2025-04-24 DOI: 10.1016/j.enconman.2025.119820

Yinong Hu , Yong Cheng , Saishuai Dai , Zhiming Yuan , Atilla Incecik

Majority of wave energy converters (WEC) have a relatively narrower capture due to their design philosophy, which focus on matching WEC’s natural frequency to a single peak frequency of a seastate spectrum. This paper introduces an innovative “Pan Flute”-type WEC embedded into a breakwater. This design consists multiple oscillating water column (OWC) units, each with a distinguished natural frequency. By strategically tuning these frequencies to span a broader sea-state spectrum rather than merely matching the peak frequency, the system achieves a wider capture bandwidth. An experimentally validated Computational Fluid Dynamics (CFD) methodology was adopted to assess the hydrodynamic performance of the proposed design in irregular waves. This new concept possesses different resonant periods of internal water column to reasonably absorb short-, moderate-, and long-period components of irregular waves by facing-wave, central and rear chambers, respectively. Additionally, the multi-chamber design transforms the sloshing motion of water column into the piston-type motion, amplifying the wave elevation inside sub-chambers as well as accelerating the vortex detachment from the chamber-wall end. Consequently, the hydrodynamic efficiency is guaranteed to be higher than 0.5 for all wave periods, and its maximum value achieves 0.82. The wave attenuation is also improved, especially for long-period waves where there is a maximum 47.8% of reduction compared with S-OWC system. The varying-draft M−OWC system adopting separate PTO units is found to be superior to adopt a corporate PTO. It is practically possible to design the optimised number and draft of sub-chambers to obtain a broad harvesting width of wave energy. These findings promote the WEC-breakwater systems to be deployed in extensive sea areas regardless of energy density.

{"title":"Broadband wave conversion by a “Pan Flute”-type multi-oscillating-water-column (M−OWC) breakwater system","authors":"Yinong Hu , Yong Cheng , Saishuai Dai , Zhiming Yuan , Atilla Incecik","doi":"10.1016/j.enconman.2025.119820","DOIUrl":"10.1016/j.enconman.2025.119820","url":null,"abstract":"<div><div>Majority of wave energy converters (WEC) have a relatively narrower capture due to their design philosophy, which focus on matching WEC’s natural frequency to a single peak frequency of a seastate spectrum. This paper introduces an innovative “Pan Flute”-type WEC embedded into a breakwater. This design consists multiple oscillating water column (OWC) units, each with a distinguished natural frequency. By strategically tuning these frequencies to span a broader sea-state spectrum rather than merely matching the peak frequency, the system achieves a wider capture bandwidth. An experimentally validated Computational Fluid Dynamics (CFD) methodology was adopted to assess the hydrodynamic performance of the proposed design in irregular waves. This new concept possesses different resonant periods of internal water column to reasonably absorb short-, moderate-, and long-period components of irregular waves by facing-wave, central and rear chambers, respectively. Additionally, the multi-chamber design transforms the sloshing motion of water column into the piston-type motion, amplifying the wave elevation inside sub-chambers as well as accelerating the vortex detachment from the chamber-wall end. Consequently, the hydrodynamic efficiency is guaranteed to be higher than 0.5 for all wave periods, and its maximum value achieves 0.82. The wave attenuation is also improved, especially for long-period waves where there is a maximum 47.8% of reduction compared with S-OWC system. The varying-draft M−OWC system adopting separate PTO units is found to be superior to adopt a corporate PTO. It is practically possible to design the optimised number and draft of sub-chambers to obtain a broad harvesting width of wave energy. These findings promote the WEC-breakwater systems to be deployed in extensive sea areas regardless of energy density.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"333 ","pages":"Article 119820"},"PeriodicalIF":9.9,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869108","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}

引用次数: 0

Numerical investigation of CPVT-LFR Fresnel reflector system under real weather conditions

IF 9.9 1区工程技术 Q1 ENERGY & FUELS

Energy Conversion and Management

Pub Date : 2025-04-24 DOI: 10.1016/j.enconman.2025.119829

Taoufik Brahim , Abdelmajid Jemni

This study presents a numerical investigation of a Concentrating Photovoltaic Thermal Linear Fresnel Reflector (CPVT-LFR) system using air and water as cooling working fluids under real Tunisian weather conditions. A quasi-transient mathematical model was developed to predict temperature distributions across all material layers of the reflector system and evaluate its thermal and electrical performance. A parametric analysis was conducted to optimize solar energy utilization. Results indicate that the air-cooled system achieves an average overall efficiency of 78.67%, which is 58.73% higher than the water-cooled system (32.46%). While the air system exhibits superior thermal performance producing 11.9 times more annual thermal energy than the water system the water system generates 1.37 times more electrical power. Additionally, distinct optimal mass flow rates were identified for maximizing either electrical or thermal efficiency. This study demonstrates the potential of CPVT-LFR systems in enhancing solar energy conversion efficiency and provides insights into designing systems tailored to specific applications.

{"title":"Numerical investigation of CPVT-LFR Fresnel reflector system under real weather conditions","authors":"Taoufik Brahim , Abdelmajid Jemni","doi":"10.1016/j.enconman.2025.119829","DOIUrl":"10.1016/j.enconman.2025.119829","url":null,"abstract":"<div><div>This study presents a numerical investigation of a Concentrating Photovoltaic Thermal Linear Fresnel Reflector (CPVT-LFR) system using air and water as cooling working fluids under real Tunisian weather conditions. A quasi-transient mathematical model was developed to predict temperature distributions across all material layers of the reflector system and evaluate its thermal and electrical performance. A parametric analysis was conducted to optimize solar energy utilization. Results indicate that the air-cooled system achieves an average overall efficiency of 78.67%, which is 58.73% higher than the water-cooled system (32.46%). While the air system exhibits superior thermal performance producing 11.9 times more annual thermal energy than the water system the water system generates 1.37 times more electrical power. Additionally, distinct optimal mass flow rates were identified for maximizing either electrical or thermal efficiency. This study demonstrates the potential of CPVT-LFR systems in enhancing solar energy conversion efficiency and provides insights into designing systems tailored to specific applications.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"333 ","pages":"Article 119829"},"PeriodicalIF":9.9,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869110","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}

引用次数: 0