Renewable Energy最新文献

{"title":"Effect analysis on thermal performance enhancement and NOx emissions reduction in hydrogen/ammonia-powered micro-combustors with porous media based on multi-field synergy theory","authors":"Lei Cai ,&nbsp;Jiaqiang E ,&nbsp;Dan Zhao ,&nbsp;Jiangjun Ding ,&nbsp;Bo Luo","doi":"10.1016/j.renene.2025.124294","DOIUrl":"10.1016/j.renene.2025.124294","url":null,"abstract":"<div><div>Micro-combustors utilizing carbon-free hydrogen/ammonia blends represent critical technologies for decarbonizing portable renewable energy devices. In this work, three-dimensional numerical simulations were firstly employed to evaluate the effect of ammonia blended ratio(<em>χ</em>) across three combustor configurations: without porous medium (C-R), fully filled with porous medium (C-F), and partially filled with an innovative annular porous medium (C-P). Results indicate that increasing <em>χ</em> shifts flames downstream improves outer wall temperature uniformity and reduces NO_x emissions. Critically, at <em>χ</em> = 90 %, the combustor C-P demonstrates substantial performance gains compared to reference combustor C-R: a 69.8 K increase in mean outer wall temperature, 25.9 % higher radiation efficiency and 44.7 % lower NO_x emissions. Leveraging combustor C-P's superiority, field synergy analysis was uniquely applied to optimize its key parameters, revealing maximum radiation efficiency at porosity of 0.8 and minimal NO_x emissions at inner diameter (non-porous zone) of 0.9 mm. This work establishes two key innovations: 1)an annular porous medium design specifically tailored for high ammonia blends; 2)using field synergy theory to elucidate fundamental mechanisms governing multi-field interactions in porous media. The optimized combustor C-P delivers exceptional thermal-radiative performance with concurrently reduced NO_x emissions under high-<em>χ</em> conditions. These advancements were useful for realizing high-performance, low-emission micro-power generation essential for next-generation portable renewable energy applications.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"256 ","pages":"Article 124294"},"PeriodicalIF":9.1,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144894761","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":"Quantitative analysis of energy harvesting characteristics for 3D side-by-side double cylinders based on entropy production theory","authors":"Zhumei Luo ,&nbsp;Han Liang ,&nbsp;Shunli Lv ,&nbsp;Tao Guo","doi":"10.1016/j.renene.2025.124265","DOIUrl":"10.1016/j.renene.2025.124265","url":null,"abstract":"<div><div>Vortex-induced vibration energy harvesting from low-velocity water flows is typically achieved using systems composed of two or more cylinders. This study performed three-dimensional numerical simulations on side-by-side dual cylinders undergoing transverse vibration at Reynolds numbers ranging from 2.79 × 10⁴ to 1.68 × 10⁵. The vortex-induced vibration responses were investigated for four side-by-side configurations with spacing ratio (<em>S/D</em>) of 2, 2.5, 3, and 4, a mass ratio (<em>m∗</em>) of 2.4, and a mass-damping ratio (<em>m∗ζ</em>) of 0.013, across a reduced velocity (<em>U</em>_<em>r</em>) range of 2–12. The results demonstrate that, within the spacing ratios <em>S</em> = 2 and 3<em>D</em> and <em>U</em>_<em>r</em> = 4–6, side-by-side dual cylinders exhibit significantly enhanced energy harvesting from water flows compared to a single cylinder. Notably, at <em>U</em>_<em>r</em> = 6, the maximum harvested power and efficiency reach 1.154 and 1.44 times those of a single cylinder, respectively. Under side-by-side configurations, it was observed that anti-phase correlation during the lock-in regime can markedly improve both the power output and efficiency of the energy-harvesting cylinders. A correspondence between distinct wake modes and energy capture performance was established by comparing the evolution of vortex dynamics and the energy harvesting results across different spacing ratios. Furthermore, the relationship between vortex evolution and entropy generation was examined, revealing that the entropy production rate caused by turbulence dissipation is the primary source of entropy production, consistent with the quantitative analysis. The local entropy production rate caused by wall shear stress is larger in vortex formation and smaller in the process of vortex shedding; this variation reflects the intensity of fluid–structure interaction. Finally, the collision situation in the side-by-side arrangement with a small spacing ratio is discussed.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"256 ","pages":"Article 124265"},"PeriodicalIF":9.1,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144907436","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":"Investment decision of concentrated solar power under uncertainty based on real options approach: A case study in Qinghai Province, China","authors":"Yanbin Li ,&nbsp;Zhaolun Pan ,&nbsp;Yuqing Chu ,&nbsp;Jiahang Yuan ,&nbsp;Yujing Shi ,&nbsp;Yun Li","doi":"10.1016/j.renene.2025.124299","DOIUrl":"10.1016/j.renene.2025.124299","url":null,"abstract":"<div><div>Concentrated Solar Power (CSP) has been regarded as a promising renewable power generation technology in the desert, but its high initial costs require careful strategic investment valuation. This study proposes a real options valuation (ROV) model solved by Weighted Least Squares Monte Carlo (WLSMC) simulation to evaluate CSP plant investment under various revenue scenarios taking uncertainties into account. This study evaluated the investment value and optimal investment timing of CSP plant in Qinghai Province, China, using the proposed model. The results showed that the ROV method, with a 10-year deferral option, demonstrates the profitability of CSP plant when choosing the appropriate investment timing. However, traditional net present value method deems investing in CSP plant unfeasible. Additionally, CSP plant that choose China Certified Emission Reduction transactions as an extra source of income will have a higher investment value compared to those engaging in tradable green certificate transactions, but the best time to invest will be later. A sensitivity analysis was also conducted to investigate potential policy options for promoting CSP plant investments in China. This study can make practical contributions to investors and provide valuable guidance to policymakers, thereby promoting the sustainable development of energy systems.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"256 ","pages":"Article 124299"},"PeriodicalIF":9.1,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144894800","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":"Assessing the efficiency of ocean thermal energy conversion in the western Atlantic off Brazil","authors":"Moacyr Araujo ,&nbsp;Carlos Noriega ,&nbsp;Amilcar Calzada ,&nbsp;Carmen Medeiros ,&nbsp;Julia Araujo ,&nbsp;Alejandro Rodriguez ,&nbsp;Humberto L. Varona","doi":"10.1016/j.renene.2025.124288","DOIUrl":"10.1016/j.renene.2025.124288","url":null,"abstract":"<div><div>This study computed thermal efficiency in Brazilian coastal areas between 5.0°N and 35.0°S and 25.0°W–55.0°W using a 40-year (1983–2022) water temperature dataset (surface and 1000 m). Thermal gradients showed no significant monthly differences over the annual cycle (Kruskal–Wallis test; p &gt; 0.05). Maximum gradients exceeded 20 °C across the study region, with high thermal efficiency coefficients (η &gt; 0.07) particularly in the Northeast. Combining efficiency and coastal proximity identified five optimal sites (P11, P6, P8, P9, P10) with η &gt; 0.07 (∼7.3 %) and distances &lt;35 km, favoring Ocean Thermal Energy Conversion (OTEC) implementation. The Northeast exhibited the greatest potential, with efficiency from 6.1 % to 7.8 %, comparable to the Caribbean Sea and exceeding values from other tropical Pacific and Atlantic areas. The results highlight the strategic advantage of the northeastern coast for OTEC, offering favorable thermal conditions and short offshore distances, reducing infrastructure costs. Harnessing this potential could enhance access to clean, sustainable energy, reduce greenhouse gas emissions, and support climate change mitigation efforts. This work contributes valuable spatial and temporal insights for future renewable energy planning in Brazil's coastal regions, emphasizing the relevance of long-term thermal data analysis for marine energy exploitation.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"256 ","pages":"Article 124288"},"PeriodicalIF":9.1,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144889586","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":"Innovative design and decoupling control of an efficient, simplified MFCS air supply system for renewable hydrogen-powered stacks","authors":"Fengxiang Chen,&nbsp;Guangyao Tong,&nbsp;Xuncheng Chi,&nbsp;Bo Zhang,&nbsp;Renzheng Li","doi":"10.1016/j.renene.2025.124283","DOIUrl":"10.1016/j.renene.2025.124283","url":null,"abstract":"<div><div>Multi-stack fuel cell systems (MFCS) are widely utilized in high-power demand applications such as distributed renewable energy power generation system due to the stability. However, these systems face challenges including complex structures and significant parameter coupling. To address these challenges, this paper proposes an efficient and simplified integrated air supply structure, which utilizing the air compressor to regulate buffer pressure and the backpressure valve to control mass flow rate, simplifying system structure and reducing air compressor power consumption by up to 43 % to improve net power. Based on this structure, this paper presents an internal model controller (IMC) that significantly reduces the settling time and decreases the mass flow overshoot by 62.6 % compared to traditional proportional-integral control methods under the mass flow rate step response for fuel cell stacks, while also reducing pressure fluctuations by 20 %. To address coupling in MFCS, a Partial Feedforward Decoupling IMC (PFD-IMC) is proposed. Compared to Full Feedforward Decoupling IMC (FFD-IMC), PFD-IMC uses a simplifier structure while achieving similar decoupling performance. It eliminates overshoot in mass flow rate step responses and reduces pressure fluctuations by 69.4 %. PFD-IMC shows superior performance in handling pressure step responses, single flow variations, and dynamic operations, significantly improving system efficiency.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"256 ","pages":"Article 124283"},"PeriodicalIF":9.1,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145018767","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":"Effects of graded-porosity gas diffusion layers used in polymer electrolyte fuel cells","authors":"Isaac C. Okereke ,&nbsp;Amirpiran Amiri ,&nbsp;Tabbi Wilberforce ,&nbsp;Mohammed S. Ismail","doi":"10.1016/j.renene.2025.124282","DOIUrl":"10.1016/j.renene.2025.124282","url":null,"abstract":"<div><div>Optimising the design of gas diffusion layers (GDLs) is essential to enhance water management and reactant transport in polymer electrolyte fuel cells (PEFCs), which are critical renewable energy conversion technologies required to decarbonise electricity. In this work, a comprehensive three-dimensional model of a PEFC has been developed to analyse the sensitivity of fuel cell performance to graded-porosity cathode GDLs under various humidity conditions and GDL thicknesses. The results show that, for most humidity conditions, the fuel cell performs best when the cathode GDL has low porosity at the catalyst interface and high porosity at the bipolar plate interface. Under relatively low humidity conditions, fuel cell performance deteriorates when using graded-porosity GDLs with higher porosity near the catalyst layer. On the other hand, under high humidity conditions, a cathode GDL with a porosity gradient improves performance compared to a GDL with uniform porosity. Further, when the GDL thickness is reduced from 300 μm to 200 μm, the best performance is achieved with a GDL that has higher porosity near the catalyst layer. These findings are discussed and justified in the study providing valuable guidance for designing advanced GDL structures to improve PEFC efficiency, supporting their wider adoption in renewable energy systems.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"256 ","pages":"Article 124282"},"PeriodicalIF":9.1,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144889584","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":"Experimental and numerical study on the auto-ignition of pressurized syngas leakage through a tube","authors":"Guowei Lyu ,&nbsp;Xiaolong Gou","doi":"10.1016/j.renene.2025.124272","DOIUrl":"10.1016/j.renene.2025.124272","url":null,"abstract":"<div><div>Integrated experimental and numerical investigations are conducted to examine tube-leakage-induced auto-ignition of H₂/CO syngas. Experimental results demonstrate that increasing the CO mole fraction significantly reduces the shock wave intensity during leakage while elevating the required ignition pressure. Notably, auto-ignition is observed at CO mole fractions up to 30 % under sufficiently high syngas-air pressure ratios. For all tested compositions, the theoretical shock Mach number remains near 3.5 at critical auto-ignition conditions. Numerical simulations indicate that syngas composition influences leakage auto-ignition primarily through shock intensity rather than chemical reactivity. A prediction method for the critical auto-ignition pressure of hydrogen-rich gas leakage is proposed. This method uses experimental data to correlate average molecular weight with theoretical critical shock Mach number, enabling the generalization of critical leakage auto-ignition pressures across different gas mixtures. Validation against current and previous unobstructed straight-tube experiments confirms the reliability of this method. This framework provides fundamental insights for risk assessment and the safe operation of syngas systems.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"256 ","pages":"Article 124272"},"PeriodicalIF":9.1,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144888769","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":"Introducing internal light source into direct absorption solar collector for enhancing photothermal conversion performance of nanofluids","authors":"Qianru Yang,&nbsp;Chenghu Zhang,&nbsp;Yan Liu,&nbsp;Zichen Lin,&nbsp;Yibo Zhao","doi":"10.1016/j.renene.2025.124276","DOIUrl":"10.1016/j.renene.2025.124276","url":null,"abstract":"<div><div>Direct absorption solar collectors (DASCs), by virtue of simplicity, environmental benefits, and cost-effectiveness, hold significant potential for solar thermal utilization. However, widespread applications face inherent limitations in photothermal conversion (PTC) efficiency due to their passive reliance on external solar irradiation. This study pioneers a novel internally radiated DASC (IR-DASC) featuring a controllable internal light source integrated within nanofluid (NF) layer. This innovative design effectively addresses the constraints of fluctuating light intensity, spectral mismatch, and optical penetration depth, thereby enhancing the PTC process using TiN-deionized water (DW)/ethylene glycol (EG) NFs. Systematic characterization under controlled flow (3-13 L/min) demonstrated a significant outlet temperature elevation of 10.52 °C and a PTC efficiency of 0.65 at optimal conditions (100 ppm, 3 L/min). As the concentration of TiN-DW/EG NF was increased from 0 ppm to 100 ppm, the heat gain efficiency was improved by at least 0.26. Spectral validation using AM1.5-matched xenon irradiation conclusively demonstrates technological viability under real-world operating conditions. Notably, the implementation of internal radiation architecture demonstrates superior thermal uniformity. Therefore, the IR-DASC provides a new paradigm, overcoming fundamental limitations of passive solar DASCs through structural innovation for enhanced efficiency and practical value.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"256 ","pages":"Article 124276"},"PeriodicalIF":9.1,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144907442","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":"Efficiency enhancement of photovoltaic modules via full-spectrum utilization and waste heat recovery using liquid-state thermocells","authors":"Fuqian Ye ,&nbsp;Xin Zhao ,&nbsp;Yuxin Zhang ,&nbsp;Yi Man ,&nbsp;Feihong Qi ,&nbsp;Xin Zhang ,&nbsp;Wanli Peng ,&nbsp;Ehsanur Rahman ,&nbsp;Juncheng Guo","doi":"10.1016/j.renene.2025.124247","DOIUrl":"10.1016/j.renene.2025.124247","url":null,"abstract":"<div><div>The photovoltaic module (PVM) primarily captures photons near the semiconductor bandgap to generate photocurrent. However, low- and high-energy photons outside this range are largely wasted as heat, limiting efficiency to approximately 33% (Shockley–Queisser limit). To utilize the full solar spectrum, a spectrally selective absorber (SSA) and a liquid thermocell (LTC) are synergistically integrated with a PVM to form a novel hybrid system for the first time. The developed model improves upon previous work by including: (i) the PVM-to-LTC area ratio, (ii) iterative energy balance to determine LTC electrode temperatures, and (iii) key irreversible losses in both subsystems. Under AM1.5G conditions (1 kW m⁻²), the proposed hybrid system has a maximum conversion efficiency of 20.70% and a electric power density of 207.0 W m⁻² when the PVM operates at 345 K. Compared to a standalone PVM, the hybrid system demonstrates a 7.64% improvement in both efficiency and power density, outperforming the PVM and solid-state thermoelectric generator hybrid technologies. Parametric studies reveal that lowering PVM and sink temperatures, narrowing LTC electrode spacing, and raising ambient temperature can significantly improve performance. This study provides a theoretical foundation for the optimal design and operation of PVM-LTC hybrid systems, offering valuable insights into solar full-spectrum utilization and waste heat recovery in PV applications.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"256 ","pages":"Article 124247"},"PeriodicalIF":9.1,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144892775","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":"Techno-economic analysis of ammonia-based hydrogen production and fuel cell systems for renewable power generation strategies","authors":"Yirong Chen ,&nbsp;Hesong Bai","doi":"10.1016/j.renene.2025.124269","DOIUrl":"10.1016/j.renene.2025.124269","url":null,"abstract":"<div><div>Due to its high hydrogen density, secure management, and current production techniques, Chinese society views ammonia as a good hydrogen storage and transit medium. The economic and technical analysis of the 2024 Ammonia to Hydrogen and Ammonia to Power routes details their energy efficiency and cost-effectiveness to estimate the cost of establishing renewable energy power producing infrastructure. High-temperature ammonia cracker units at 600 °C have 88.56 and 87.010 percent energy and exergy efficiency, respectively. Hydrogen has a Levelized Cost of 3.82 USD/kg, and Pressure Swing Adsorption Driver technology has the lowest costs and lowest efficiency reduction in hydrogen separations. The high-temperature cracker and solid oxide fuel cell technology provide top system efficiency of 70.56 % and a Levelized Cost of Electricity of 0.146 USD/kWh. During hydrogen burning season, the ethanol-yeast process performs worse. This research shows that ammonia may use economic and technological improvements to transport renewable energy in China by guiding hydrogen adoption and policymaking.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"256 ","pages":"Article 124269"},"PeriodicalIF":9.1,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144888770","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}