Pub Date : 2026-01-20DOI: 10.1016/j.renene.2026.125311
Xueli Shi , Jiawang Chen , Qiaoling Gao , Ping Tang , Fang He
This study, based on wave-current interaction simulation data from 1996 to 2022, systematically evaluates the energy density, stability, and availability of wave and tidal current energy in the China's Eastern Adjacent Seas. The threshold method is used to explore wave-current synergy, and an improved co-location feasibility index is proposed to identify four combined hotspots: Zhoushan, Taizhou, Penghu, and New Taipei. By constructing resource availability, sustainability, and complementarity indices, the wave-current complementarity characteristics of these hotspots are further analyzed. The performance of wave-current combined power systems under actual power load scenarios is also investigated, examining the impact of renewable energy penetration and wave energy capacity configuration on grid-balanced energy demand. The results show that the wave energy availability in representative sea areas is 38.0 %–40.7 %, and the complementarity score is 12.9 %–22.4 %. The combined system (50 % wave energy installed capacity) can reduce the monthly coefficient of variation by 20 %–50 %, significantly smoothing power output fluctuations and reducing annual balanced energy demand (e.g., in Taizhou, with = 1.0 and = 0.5, the annual normalized balanced energy demand decreased from 5300 to 4000, a reduction of 24.5 %). The combined system can also reduce the peak-to-valley ratio of balanced energy demand, alleviating the burden of rapid grid regulation.
{"title":"Complementary value of wave and tidal current energy in the power grid and their impact on balanced energy demand","authors":"Xueli Shi , Jiawang Chen , Qiaoling Gao , Ping Tang , Fang He","doi":"10.1016/j.renene.2026.125311","DOIUrl":"10.1016/j.renene.2026.125311","url":null,"abstract":"<div><div>This study, based on wave-current interaction simulation data from 1996 to 2022, systematically evaluates the energy density, stability, and availability of wave and tidal current energy in the China's Eastern Adjacent Seas. The threshold method is used to explore wave-current synergy, and an improved co-location feasibility index is proposed to identify four combined hotspots: Zhoushan, Taizhou, Penghu, and New Taipei. By constructing resource availability, sustainability, and complementarity indices, the wave-current complementarity characteristics of these hotspots are further analyzed. The performance of wave-current combined power systems under actual power load scenarios is also investigated, examining the impact of renewable energy penetration and wave energy capacity configuration on grid-balanced energy demand. The results show that the wave energy availability in representative sea areas is 38.0 %–40.7 %, and the complementarity score is 12.9 %–22.4 %. The combined system (50 % wave energy installed capacity) can reduce the monthly coefficient of variation by 20 %–50 %, significantly smoothing power output fluctuations and reducing annual balanced energy demand (e.g., in Taizhou, with <span><math><mrow><mi>α</mi></mrow></math></span> = 1.0 and <span><math><mrow><msub><mi>β</mi><mi>M</mi></msub></mrow></math></span> = 0.5, the annual normalized balanced energy demand decreased from 5300 to 4000, a reduction of 24.5 %). The combined system can also reduce the peak-to-valley ratio of balanced energy demand, alleviating the burden of rapid grid regulation.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"261 ","pages":"Article 125311"},"PeriodicalIF":9.1,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-20DOI: 10.1016/j.renene.2026.125313
Chuan Lin , Zhihui Yu , Wenhao Chen , Qinghua Lin , Cheng Zhang
Short-term photovoltaic power forecasting (SPPF) is vital for grid integration of renewable energy but remains challenging due to meteorological influences. While graph neural networks (GNNs) excel at capturing spatiotemporal correlations in SPPF, existing methods overlook causal relationships between weather factors and photovoltaic (PV) output, limiting accuracy. Thus, this paper proposes a causal graph attention network (CGAT) that employs convergent cross mapping (CCM) to calculate the causal intensity among factors related to photovoltaic power. Initially, we consider the causal relationship between PV power generation and meteorological factors, constructing a dynamic causal graph where photovoltaic power and meteorological factors are represented as nodes, and causal intensity serves as edge attributes. Subsequently, we employed graph attention network (GAT) and long short-term memory network (LSTM) to extract spatial and temporal characteristics between meteorological factors and photovoltaic power at each time stamp, thereby achieving accurate SPPF. Finally, the experimental results obtained from the actual operation of the photovoltaic power station show that under extremely challenging in summer, the forecasting performance of the proposed model is still superior to that of the existing state-of-the-art models, and its root mean square error (RMSE) has been reduced by up to 5.6%.
{"title":"A novel causal graph attention network with convergent cross mapping for short-term photovoltaic power forecasting","authors":"Chuan Lin , Zhihui Yu , Wenhao Chen , Qinghua Lin , Cheng Zhang","doi":"10.1016/j.renene.2026.125313","DOIUrl":"10.1016/j.renene.2026.125313","url":null,"abstract":"<div><div>Short-term photovoltaic power forecasting (SPPF) is vital for grid integration of renewable energy but remains challenging due to meteorological influences. While graph neural networks (GNNs) excel at capturing spatiotemporal correlations in SPPF, existing methods overlook causal relationships between weather factors and photovoltaic (PV) output, limiting accuracy. Thus, this paper proposes a causal graph attention network (CGAT) that employs convergent cross mapping (CCM) to calculate the causal intensity among factors related to photovoltaic power. Initially, we consider the causal relationship between PV power generation and meteorological factors, constructing a dynamic causal graph where photovoltaic power and meteorological factors are represented as nodes, and causal intensity serves as edge attributes. Subsequently, we employed graph attention network (GAT) and long short-term memory network (LSTM) to extract spatial and temporal characteristics between meteorological factors and photovoltaic power at each time stamp, thereby achieving accurate SPPF. Finally, the experimental results obtained from the actual operation of the photovoltaic power station show that under extremely challenging in summer, the forecasting performance of the proposed model is still superior to that of the existing state-of-the-art models, and its root mean square error (RMSE) has been reduced by up to 5.6%.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"261 ","pages":"Article 125313"},"PeriodicalIF":9.1,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-20DOI: 10.1016/j.renene.2026.125308
Gang Wang , Tao Bai , Tianlin Zou , Zeshao Chen
Solar energy is meaningful for energy structure transformation. This paper presents a comparison study of four different schemes of a novel solar tower receiver multigeneration system for providing electric power, hydrogen and oxygen. Super-critical CO2 Brayton cycle and organic Rankine cycle driven hydrogen production block are coupled in the proposed multigeneration system. Operation, exergy, economic and environmental analyses of four different multigeneration system schemes are conducted by using Ebsilon software, and the results show that Scheme 1, in which the evaporator of organic Rankine cycle is arranged downstream of the main heat exchanger of Brayton cycle, has the best exergy performance as it has the smallest overall exergy loss (273.99 MW) and highest exergy efficiency (26.7 %). By contrast, Scheme 4, in which the evaporator is used as the pre-cooler of the Brayton cycle, has the best operation, economic and environmental performances simultaneously. For Scheme 4, the output power, Brayton cycle efficiency, hydrogen and oxygen production rates are 64.32 MW, 50.53 %, 181.2 kg h−1 and 1449.6 kg h−1, levelized costs of electricity and hydrogen are 0.0687 $·kWh−1 and 4.44 $·kg−1, and the net present value and investment recovery period are 984.2 $M and 7.25 years. And annual emission reduction quantities of CO2, soot, SO2 and NOx of Scheme 4 are 88723.3 t, 1271.3 t, 2184.9 t and 2065.8 t.
太阳能对能源结构转型具有重要意义。本文介绍了一种新型的太阳能塔式多源发电系统的四种不同方案的比较研究。超临界CO2布雷顿循环和有机朗肯循环驱动的制氢区块在多代系统中耦合。利用Ebsilon软件对4种不同的多发电系统方案进行了运行、火用、经济和环境分析，结果表明，将有机朗肯循环蒸发器布置在布雷顿循环主换热器下游的方案1的火用性能最佳，总火用损失最小（273.99 MW），火用效率最高（26.7%）。方案4采用蒸发器作为Brayton循环的预冷器，同时具有最佳的运行、经济和环境性能。方案4的输出功率、Brayton循环效率、产氢率和产氧率分别为64.32 MW、50.53%、181.2 kg h−1和1449.6 kg h−1，电、氢平化成本分别为0.0687美元·kWh−1和4.44美元·kg−1，净现值和投资回收期分别为984.2美元和7.25年。方案4的CO2、soot、SO2和NOx年减排量分别为88723.3 t、1271.3 t、2184.9 t和2065.8 t。
{"title":"Comparative study of different schemes of a novel solar tower receiver multigeneration system with SCO2 Brayton cycle and ORC","authors":"Gang Wang , Tao Bai , Tianlin Zou , Zeshao Chen","doi":"10.1016/j.renene.2026.125308","DOIUrl":"10.1016/j.renene.2026.125308","url":null,"abstract":"<div><div>Solar energy is meaningful for energy structure transformation. This paper presents a comparison study of four different schemes of a novel solar tower receiver multigeneration system for providing electric power, hydrogen and oxygen. Super-critical CO<sub>2</sub> Brayton cycle and organic Rankine cycle driven hydrogen production block are coupled in the proposed multigeneration system. Operation, exergy, economic and environmental analyses of four different multigeneration system schemes are conducted by using Ebsilon software, and the results show that Scheme 1, in which the evaporator of organic Rankine cycle is arranged downstream of the main heat exchanger of Brayton cycle, has the best exergy performance as it has the smallest overall exergy loss (273.99 MW) and highest exergy efficiency (26.7 %). By contrast, Scheme 4, in which the evaporator is used as the pre-cooler of the Brayton cycle, has the best operation, economic and environmental performances simultaneously. For Scheme 4, the output power, Brayton cycle efficiency, hydrogen and oxygen production rates are 64.32 MW, 50.53 %, 181.2 kg h<sup>−1</sup> and 1449.6 kg h<sup>−1</sup>, levelized costs of electricity and hydrogen are 0.0687 $·kWh<sup>−1</sup> and 4.44 $·kg<sup>−1</sup>, and the net present value and investment recovery period are 984.2 $M and 7.25 years. And annual emission reduction quantities of CO<sub>2</sub>, soot, SO<sub>2</sub> and NO<sub>x</sub> of Scheme 4 are 88723.3 t, 1271.3 t, 2184.9 t and 2065.8 t.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"261 ","pages":"Article 125308"},"PeriodicalIF":9.1,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-19DOI: 10.1016/j.renene.2026.125310
Dominic Yellezuome , Xianpu Zhu , Ronghou Liu , Chen Sun , Mohamed Hemida Abd-Alla , Abdel-Hamied M. Rasmey
Acidogenic gas (H2 and CO2) from acidogenic reactors is often ignored in two-stage anaerobic digestion due to its high CO2 content. While biogas recirculation improves methane production and substrate utilization, the underlying metabolic mechanisms remain unclear. This study explores these mechanisms using metagenomics in a novel two-stage system utilizing acidogenic gas. Biogas recirculation in the methanogenic stage increased average methane yield from 554 to 608 mL/g VS as the flow rate rose from 0 to 0.4 L/min, with a peak of 696 mL/g VS at 0.4 L/min. However, the methane yield decreased to 586 mL/g VS at 0.8 L/min. Recirculation enriched fermentative bacteria, boosting soluble metabolite production but slightly reducing organic matter removal. Although dominant microbial communities were significantly unaltered, syntrophic bacteria such as norank_f__norank_o__MBA03 (8.8–12.2 %) were enriched, strengthening microbial networks. Different methanogenic genera emerged, enabling rapid metabolite consumption via hydrogenotrophic, acetoclastic, and methylotrophic pathways. Metagenomic analysis revealed that recirculation upregulated key functions like signal transduction, cell motility, aromatic degradation, methanogenesis, and possible methane oxidation. This promoted carbon substrate availability and methane production while highlighting potential for valuable biochemical recovery from volatile fatty acids, supporting the circular economy and enhancing the cost-effectiveness of biogas systems.
{"title":"Enhanced acidogenic gas utilization in two-stage co-digestion via biogas recirculation: Metagenomics analysis","authors":"Dominic Yellezuome , Xianpu Zhu , Ronghou Liu , Chen Sun , Mohamed Hemida Abd-Alla , Abdel-Hamied M. Rasmey","doi":"10.1016/j.renene.2026.125310","DOIUrl":"10.1016/j.renene.2026.125310","url":null,"abstract":"<div><div>Acidogenic gas (H<sub>2</sub> and CO<sub>2</sub>) from acidogenic reactors is often ignored in two-stage anaerobic digestion due to its high CO<sub>2</sub> content. While biogas recirculation improves methane production and substrate utilization, the underlying metabolic mechanisms remain unclear. This study explores these mechanisms using metagenomics in a novel two-stage system utilizing acidogenic gas. Biogas recirculation in the methanogenic stage increased average methane yield from 554 to 608 mL/g VS as the flow rate rose from 0 to 0.4 L/min, with a peak of 696 mL/g VS at 0.4 L/min. However, the methane yield decreased to 586 mL/g VS at 0.8 L/min. Recirculation enriched fermentative bacteria, boosting soluble metabolite production but slightly reducing organic matter removal. Although dominant microbial communities were significantly unaltered, syntrophic bacteria such as norank_f__norank_o__MBA03 (8.8–12.2 %) were enriched, strengthening microbial networks. Different methanogenic genera emerged, enabling rapid metabolite consumption via hydrogenotrophic, acetoclastic, and methylotrophic pathways. Metagenomic analysis revealed that recirculation upregulated key functions like signal transduction, cell motility, aromatic degradation, methanogenesis, and possible methane oxidation. This promoted carbon substrate availability and methane production while highlighting potential for valuable biochemical recovery from volatile fatty acids, supporting the circular economy and enhancing the cost-effectiveness of biogas systems.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"261 ","pages":"Article 125310"},"PeriodicalIF":9.1,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035661","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}
In this work, a design optimization method for hybrid power system with hybrid electricity-hydrogen energy storage system under uncertainties is established. Firstly, a novel approach for modeling the interdependencies between the solar and wind energy uncertainties and load uncertainty is developed. Then, a two-stage collaborative design optimization model is constructed, where the first stage is to size the renewable energy capacities, and the second stage is to determine the hybrid energy storage system capacity and power dispatching scheme by simultaneously considering economy and resilience. Finally, the effectiveness of the proposed method is verified through a case study of a photovoltaic-wind-battery-hydrogen hybrid power system. The results show that the proposed uncertainty models can exactly describe the randomness and fluctuation characteristics of the hybrid power system, and the total annual and operating costs of the system in trade-off point are 5.38 × 106 $ and 2.00 × 105 $. The battery energy storage system is better than the hydrogen one in the system, and the combination of the both ones is more beneficial for the improvement of the economy and resilience. Furthermore, the influences of the investment and operation costs on the hybrid power system are comprehensively analyzed and discussed.
{"title":"Design optimization method for electricity-hydrogen energy storage system under uncertainties","authors":"Shuai Sun , Kelei Huang , Zhangfa Tong , Yinghua Jiang","doi":"10.1016/j.renene.2026.125307","DOIUrl":"10.1016/j.renene.2026.125307","url":null,"abstract":"<div><div>In this work, a design optimization method for hybrid power system with hybrid electricity-hydrogen energy storage system under uncertainties is established. Firstly, a novel approach for modeling the interdependencies between the solar and wind energy uncertainties and load uncertainty is developed. Then, a two-stage collaborative design optimization model is constructed, where the first stage is to size the renewable energy capacities, and the second stage is to determine the hybrid energy storage system capacity and power dispatching scheme by simultaneously considering economy and resilience. Finally, the effectiveness of the proposed method is verified through a case study of a photovoltaic-wind-battery-hydrogen hybrid power system. The results show that the proposed uncertainty models can exactly describe the randomness and fluctuation characteristics of the hybrid power system, and the total annual and operating costs of the system in trade-off point are 5.38 × 10<sup>6</sup> $ and 2.00 × 10<sup>5</sup> $. The battery energy storage system is better than the hydrogen one in the system, and the combination of the both ones is more beneficial for the improvement of the economy and resilience. Furthermore, the influences of the investment and operation costs on the hybrid power system are comprehensively analyzed and discussed.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"261 ","pages":"Article 125307"},"PeriodicalIF":9.1,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-19DOI: 10.1016/j.renene.2026.125262
Martin C. Jang , Vincent S. Neary , Kevin A. Haas
The present study characterizes published acoustic Doppler current profiler measurements from twenty potential tidal energy sites, classifying the profiles based on their velocity shape, while analyzing their prevalence and mean characteristics by flow regime. Most of the observed profiles (87 %) are monotonic. A 1/6.5th power law models 89 % of the mean profiles within ±10 %. A small fraction of the profiles (13 %) exhibits non-monotonic behavior during different phases of the tidal cycle or in the presence of complex bathymetric features and other hydrodynamic forcing. Non-monotonic behavior is found to be correlated with the flow depth Reynolds number, indicating the influence of depth and local turbulence intensity in shaping the vertical flow structure. While its occurrence is low compared to monotonic behavior, it is characterized by sharp velocity gradients and velocity deficits that impact turbine design and energy production by increasing shear forces and altering load distributions. These findings demonstrate the efficacy of canonical power law models commonly used to approximate reference inflow conditions for current energy converters but underscore the need for detailed profile characterization for tidal energy resource assessment, tidal energy converter design, and power performance assessment.
{"title":"Current depth profile characterization for tidal energy development","authors":"Martin C. Jang , Vincent S. Neary , Kevin A. Haas","doi":"10.1016/j.renene.2026.125262","DOIUrl":"10.1016/j.renene.2026.125262","url":null,"abstract":"<div><div>The present study characterizes published acoustic Doppler current profiler measurements from twenty potential tidal energy sites, classifying the profiles based on their velocity shape, while analyzing their prevalence and mean characteristics by flow regime. Most of the observed profiles (87 %) are monotonic. A 1/6.5th power law models 89 % of the mean profiles within ±10 %. A small fraction of the profiles (13 %) exhibits non-monotonic behavior during different phases of the tidal cycle or in the presence of complex bathymetric features and other hydrodynamic forcing. Non-monotonic behavior is found to be correlated with the flow depth Reynolds number, indicating the influence of depth and local turbulence intensity in shaping the vertical flow structure. While its occurrence is low compared to monotonic behavior, it is characterized by sharp velocity gradients and velocity deficits that impact turbine design and energy production by increasing shear forces and altering load distributions. These findings demonstrate the efficacy of canonical power law models commonly used to approximate reference inflow conditions for current energy converters but underscore the need for detailed profile characterization for tidal energy resource assessment, tidal energy converter design, and power performance assessment.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"261 ","pages":"Article 125262"},"PeriodicalIF":9.1,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-19DOI: 10.1016/j.renene.2026.125309
Fatih Demir, Orhan Kalkan
Jet impingement cooling is widely recognized as one of the most effective methods for achieving high heat transfer rates in compact systems, making it particularly suitable for cooling photovoltaic devices. This paper investigates the effects of newly designed coaxial nozzle configurations on the thermal management of a high-concentration photovoltaic system. Four different nozzle geometries, such as square, circular, hexagonal, and triangular, are considered, with constant outer cross-sectional areas, while the inner sections are designed to diverge or converge. Simulations are performed for Reynolds numbers of 2000–4000 and dimensionless coaxial nozzle-heat sink distances of 0.5–3. The results reveal that the coaxial nozzle enhances heat transfer performance compared to conventional nozzles. The diverged triangular coaxial nozzle achieves the best heat transfer at a Reynolds number of 4000, with a 19 % increase in the modified Nusselt number compared to the conventional triangular nozzle. The highest temperature uniformity (6.39 °C) is observed in the converged hexagonal coaxial nozzle, while the lowest maximum and average cell temperatures (46.1 °C and 44 °C) are achieved with the diverged triangular coaxial nozzle. The lowest pressure drop (1297 Pa) is found in a diverged hexagonal coaxial nozzle, corresponding to the lowest net electrical power (17.53 W) and cell efficiency (38.97 %). Despite the pressure drops, the diverged triangular coaxial nozzle achieves the highest electrical efficiency of 39.41 %, as its geometry promotes favorable power generation. The coaxial configuration increases the cell efficiency by up to 1.13 % and improves temperature uniformity by 23.3 %. Total exergy follows the same trend as electrical exergy, with the converged hexagonal coaxial nozzle exhibiting the highest total exergy efficiency of 38.35 %. The findings demonstrate that coaxial nozzles can significantly improve thermal uniformity and system efficiency in high-concentration photovoltaic cooling applications.
{"title":"Comparative study of diverging and converging coaxial jet nozzles for thermal management of H-CPV modules","authors":"Fatih Demir, Orhan Kalkan","doi":"10.1016/j.renene.2026.125309","DOIUrl":"10.1016/j.renene.2026.125309","url":null,"abstract":"<div><div>Jet impingement cooling is widely recognized as one of the most effective methods for achieving high heat transfer rates in compact systems, making it particularly suitable for cooling photovoltaic devices. This paper investigates the effects of newly designed coaxial nozzle configurations on the thermal management of a high-concentration photovoltaic system. Four different nozzle geometries, such as square, circular, hexagonal, and triangular, are considered, with constant outer cross-sectional areas, while the inner sections are designed to diverge or converge. Simulations are performed for Reynolds numbers of 2000–4000 and dimensionless coaxial nozzle-heat sink distances of 0.5–3. The results reveal that the coaxial nozzle enhances heat transfer performance compared to conventional nozzles. The diverged triangular coaxial nozzle achieves the best heat transfer at a Reynolds number of 4000, with a 19 % increase in the modified Nusselt number compared to the conventional triangular nozzle. The highest temperature uniformity (6.39 °C) is observed in the converged hexagonal coaxial nozzle, while the lowest maximum and average cell temperatures (46.1 °C and 44 °C) are achieved with the diverged triangular coaxial nozzle. The lowest pressure drop (1297 Pa) is found in a diverged hexagonal coaxial nozzle, corresponding to the lowest net electrical power (17.53 W) and cell efficiency (38.97 %). Despite the pressure drops, the diverged triangular coaxial nozzle achieves the highest electrical efficiency of 39.41 %, as its geometry promotes favorable power generation. The coaxial configuration increases the cell efficiency by up to 1.13 % and improves temperature uniformity by 23.3 %. Total exergy follows the same trend as electrical exergy, with the converged hexagonal coaxial nozzle exhibiting the highest total exergy efficiency of 38.35 %. The findings demonstrate that coaxial nozzles can significantly improve thermal uniformity and system efficiency in high-concentration photovoltaic cooling applications.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"261 ","pages":"Article 125309"},"PeriodicalIF":9.1,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-19DOI: 10.1016/j.renene.2026.125271
Maha Alharbi , Fuhaid Alshammari , Sattam Alharbi , Nujud A. Almuzaini , Ahmed S. Alshammari , Mohamed Elashmawy
Tubular solar stills represent a promising approach for advancing solar-driven desalination. A major limitation of conventional tubular solar still designs is the restricted evaporation surface compared to the condensation area. This study addresses that limitation by incorporating three troughs lined with black wick materials to expand the evaporation surface. A compound parabolic concentrator was employed to redirect solar irradiance toward the middle and lower evaporator surfaces, thereby reducing shading caused by the upper trough. Experimental evaluation was carried out for two configurations: the developed three-trough design and the conventional single-trough design. The developed design achieved freshwater yield of 3.45 L/m2day and efficiency of 38 %, with a production cost of $0.00774/L. In contrast, the conventional single-trough system yielded 2.552 L/m2day at 28.1 % efficiency and production cost of $0.00971/L. Employing three evaporators with the compound parabolic concentrator improved yield and efficiency by 34.19 % and 35.71 %, respectively, while reducing cost by 20.29 %. The system operates entirely off grid, making it suitable for rural deployment and scalable for commercial desalination applications.
{"title":"Innovative tubular solar still with triple evaporation stages and compound parabolic concentrator","authors":"Maha Alharbi , Fuhaid Alshammari , Sattam Alharbi , Nujud A. Almuzaini , Ahmed S. Alshammari , Mohamed Elashmawy","doi":"10.1016/j.renene.2026.125271","DOIUrl":"10.1016/j.renene.2026.125271","url":null,"abstract":"<div><div>Tubular solar stills represent a promising approach for advancing solar-driven desalination. A major limitation of conventional tubular solar still designs is the restricted evaporation surface compared to the condensation area. This study addresses that limitation by incorporating three troughs lined with black wick materials to expand the evaporation surface. A compound parabolic concentrator was employed to redirect solar irradiance toward the middle and lower evaporator surfaces, thereby reducing shading caused by the upper trough. Experimental evaluation was carried out for two configurations: the developed three-trough design and the conventional single-trough design. The developed design achieved freshwater yield of 3.45 L/m<sup>2</sup>day and efficiency of 38 %, with a production cost of $0.00774/L. In contrast, the conventional single-trough system yielded 2.552 L/m<sup>2</sup>day at 28.1 % efficiency and production cost of $0.00971/L. Employing three evaporators with the compound parabolic concentrator improved yield and efficiency by 34.19 % and 35.71 %, respectively, while reducing cost by 20.29 %. The system operates entirely off grid, making it suitable for rural deployment and scalable for commercial desalination applications.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"261 ","pages":"Article 125271"},"PeriodicalIF":9.1,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-18DOI: 10.1016/j.renene.2026.125292
Yanbin Li , Minghao Song , Yujie Hu , Yuchen Wang , Yaxuan Han , Bingkang Li , Feng Zhang
With the growing demand for photovoltaic (PV) construction, issues related to limited PV land use and low utilization efficiency are becoming increasingly evident. Hydrogen energy storage (HES) has the potential to mitigate fluctuations in photovoltaic output and enhance its overall utilization efficiency. However, current research on the application of high-purity oxygen generated during hydrogen production remains scarce. By integrating PV and HES within fishery scenarios—such as installing PV panels on the surface of fish ponds and utilizing the oxygen produced by HES for fish—it is possible to achieve a synergistic relationship among fishery, PV, and HES resources. In light of this, this paper proposes the design of a fishery-surface PV-HES (FPH) microgrid. Through an investigation into the planning and operational optimization of the FPH microgrid, the substantial complementary potential of fishery, PV and HES is explored. Firstly, with the goal of minimizing the annualized total cost, the FPH microgrid planning and operation optimization model is constructed. Furthermore, the improved k-means clustering and the backward elimination algorithms are combined to generate a typical scenario set of solar irradiation, temperature as well as electric load. Then, the spinning reserve feasibility of the planning scheme under the typical scenario set is verified, and the same algorithms are used to select typical extreme scenarios from the verified infeasible scenarios. Finally, simulation is carried out based on the selected typical scenarios and typical extreme scenarios and mainly verifies that: 1) The life of the constructed FPH microgrid is 25 years, the investment payback period is 9.17 years, and the internal rate of return is 14.64 %, which has the potential for sustainable operation and development. 2) The proposed typical scenario and typical extreme scenario selection method considering the availability of spinning reserve can overcome the shortcomings of the traditional typical scenario and worst scenario selection, so that the FPH microgrid planning result can achieve economic construction, reliable operation and high proportion of PV output accommodation.
{"title":"Fishery microgrid planning involving surface photovoltaic and hydrogen/oxygen utilization under typical extreme scenarios","authors":"Yanbin Li , Minghao Song , Yujie Hu , Yuchen Wang , Yaxuan Han , Bingkang Li , Feng Zhang","doi":"10.1016/j.renene.2026.125292","DOIUrl":"10.1016/j.renene.2026.125292","url":null,"abstract":"<div><div>With the growing demand for photovoltaic (PV) construction, issues related to limited PV land use and low utilization efficiency are becoming increasingly evident. Hydrogen energy storage (HES) has the potential to mitigate fluctuations in photovoltaic output and enhance its overall utilization efficiency. However, current research on the application of high-purity oxygen generated during hydrogen production remains scarce. By integrating PV and HES within fishery scenarios—such as installing PV panels on the surface of fish ponds and utilizing the oxygen produced by HES for fish—it is possible to achieve a synergistic relationship among fishery, PV, and HES resources. In light of this, this paper proposes the design of a fishery-surface PV-HES (FPH) microgrid. Through an investigation into the planning and operational optimization of the FPH microgrid, the substantial complementary potential of fishery, PV and HES is explored. Firstly, with the goal of minimizing the annualized total cost, the FPH microgrid planning and operation optimization model is constructed. Furthermore, the improved k-means clustering and the backward elimination algorithms are combined to generate a typical scenario set of solar irradiation, temperature as well as electric load. Then, the spinning reserve feasibility of the planning scheme under the typical scenario set is verified, and the same algorithms are used to select typical extreme scenarios from the verified infeasible scenarios. Finally, simulation is carried out based on the selected typical scenarios and typical extreme scenarios and mainly verifies that: 1) The life of the constructed FPH microgrid is 25 years, the investment payback period is 9.17 years, and the internal rate of return is 14.64 %, which has the potential for sustainable operation and development. 2) The proposed typical scenario and typical extreme scenario selection method considering the availability of spinning reserve can overcome the shortcomings of the traditional typical scenario and worst scenario selection, so that the FPH microgrid planning result can achieve economic construction, reliable operation and high proportion of PV output accommodation.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"261 ","pages":"Article 125292"},"PeriodicalIF":9.1,"publicationDate":"2026-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-18DOI: 10.1016/j.renene.2026.125261
Changwei Zhang , Liheng Deng , Jiaming Wu , Changsheng Su , Senxin Xu , Bin Wang , Di Cai , Peiyong Qin
A two-stage fractionation strategy integrating steam explosion (SE) with cyclical organosolv (CO) was developed to valorize corn stover (CS) for enhanced acetone-butanol-ethanol (ABE) production. Under the optimized condition (180 °C for ABE pulping), the glucan-enriched pulp afforded a high glucose yield (86.99 %) with a low dosage of cellulase (7 FPU/g) in the subsequent saccharification process. Moreover, alcohol compounds present in the crude ABE pulping liquor could effectively alkylate the α-carbon atom via etherification and promote the demethoxylation of lignin. After mixing the washing water from the SE stage with the CS pulp from the CO stage, the obtained liquid could be directly used as a substrate for ABE fermentation. Mass balance showed that 117.3 g of technical lignin and 128.2 g ABE were co-generated from 1 kg of dry CS using this novel fractionation process. Overall, this study enables the high-value utilization of all lignocellulosic components and provides a foundation for further intensification of biorefinery processes toward cost-effective biobutanol production, while also demonstrating the recyclability potential of ABE within integrated biorefinery systems.
采用蒸汽爆炸（SE）与循环有机溶剂（CO）相结合的两级分馏策略，对玉米秸秆（CS）进行了强化丙酮-丁醇-乙醇（ABE）生产。在优化条件下（180℃），在后续糖化过程中，纤维素酶用量较低（7 FPU/g），富葡聚糖浆的葡萄糖产率高达86.99%。此外，ABE粗浆液中存在的醇类化合物可以通过醚化作用有效地使α-碳原子烷基化，促进木质素的脱甲氧基化。将SE阶段的洗涤水与CO阶段的CS浆混合后，所得液可直接作为ABE发酵的底物。质量平衡表明，使用这种新型分馏工艺，从1kg干CS中共产生117.3 g技术木质素和128.2 g ABE。总的来说，这项研究使所有木质纤维素成分的高价值利用成为可能，并为进一步加强生物炼制过程以实现具有成本效益的生物丁醇生产提供了基础，同时也展示了ABE在集成生物炼制系统中的可回收性潜力。
{"title":"Utilization of a combined fractionation process involving steam explosion and the recycling of self-produced acetone-butanol-ethanol to promote biomass valorisation","authors":"Changwei Zhang , Liheng Deng , Jiaming Wu , Changsheng Su , Senxin Xu , Bin Wang , Di Cai , Peiyong Qin","doi":"10.1016/j.renene.2026.125261","DOIUrl":"10.1016/j.renene.2026.125261","url":null,"abstract":"<div><div>A two-stage fractionation strategy integrating steam explosion (SE) with cyclical organosolv (CO) was developed to valorize corn stover (CS) for enhanced acetone-butanol-ethanol (ABE) production. Under the optimized condition (180 °C for ABE pulping), the glucan-enriched pulp afforded a high glucose yield (86.99 %) with a low dosage of cellulase (7 FPU/g) in the subsequent saccharification process. Moreover, alcohol compounds present in the crude ABE pulping liquor could effectively alkylate the α-carbon atom via etherification and promote the demethoxylation of lignin. After mixing the washing water from the SE stage with the CS pulp from the CO stage, the obtained liquid could be directly used as a substrate for ABE fermentation. Mass balance showed that 117.3 g of technical lignin and 128.2 g ABE were co-generated from 1 kg of dry CS using this novel fractionation process. Overall, this study enables the high-value utilization of all lignocellulosic components and provides a foundation for further intensification of biorefinery processes toward cost-effective biobutanol production, while also demonstrating the recyclability potential of ABE within integrated biorefinery systems.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"261 ","pages":"Article 125261"},"PeriodicalIF":9.1,"publicationDate":"2026-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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