Renewable Energy最新文献_第3页

Analysis of public policies in the Republic of Benin to encourage the electricity generation from renewable energy sources 贝宁共和国鼓励利用可再生能源发电的公共政策分析

IF 9 1区工程技术 Q1 ENERGY & FUELS

Renewable Energy

Pub Date : 2025-04-21 DOI: 10.1016/j.renene.2025.123220

Johnson Herlich Roslee Mensah , Geraldo Lucio Tiago Filho , Ivan Felipe Silva dos Santos , Sabi Yari Moise Bandiri , Pacifique Matabishi Koshikwinja , Pierluigi Leone

The Republic of Benin, like many countries in Sub-Saharan Africa (SSA), has a high potential for renewable energy generation, but faces many challenges to harness it. The objective of this paper is to assess the current energy scenario in Benin and to analyze the policies, strategies and challenges for the development of renewables in the country. The text provides a comprehensive overview of the country's energy situation, its energy policies, and the challenges the country faces in achieving a sustainable energy transition. The study drew on published articles and international references from Scopus to provide an evidence-based assessment of the effectiveness of Benin's renewable energy policies. The conclusion is that, despite political incentives and some progress due to government efforts, significant challenges remain, including investments, limited technical capacity and lack of adequate infrastructure in the country. This analysis shows important policy implications for the design and implementation of effective renewable energy policies in the Republic of Benin and other countries in sub-Saharan Africa.

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引用次数: 0

In-pipe drag-based turbine blade optimization for energy harvesting in urban water networks: A novel theoretical approach

IF 9 1区工程技术 Q1 ENERGY & FUELS

Renewable Energy

Pub Date : 2025-04-21 DOI: 10.1016/j.renene.2025.123208

Peyman Sobhani, Nima Hasanzadeh, Mohammad J. Rostamani, Amir F. Najafi

Recent urbanization trends, along with economic and population growth, have led to increasing global energy demand. In response, in-pipe turbines have gained attention for harnessing hydrokinetic energy from urban water pipelines. Among the various turbine models, vertical-axis drag-based turbines are prevalent in plants with small-diameter pipelines. However, despite recent efforts to identify optimal design of these turbines, the optimization process remains challenging due to the numerous blade profile parameters involved. Accordingly, this paper focuses on introducing a fast and reliable blade shape optimization approach. Firstly, a parametric modeling method is introduced to create different blade geometries. Following this, a theoretical method was developed to calculate the turbine torque coefficient. The reliability of this method was assessed by comparing its results with numerical simulations. The accuracy of the numerical simulations was further validated through experimental tests, revealing a maximum deviation of 6.4 %. Subsequently, a multi-objective optimization technique (NSGA-II) is employed to maximize the turbine's output torque, with the turbine's geometrical features serving as constrains. As a result, the numerical simulations indicated that the proposed design achieved a 40 % increase in torque coefficient and a 38 % improvement in efficiency compared to the conventional model in the bounds of the practical rotational speeds.

{"title":"In-pipe drag-based turbine blade optimization for energy harvesting in urban water networks: A novel theoretical approach","authors":"Peyman Sobhani, Nima Hasanzadeh, Mohammad J. Rostamani, Amir F. Najafi","doi":"10.1016/j.renene.2025.123208","DOIUrl":"10.1016/j.renene.2025.123208","url":null,"abstract":"<div><div>Recent urbanization trends, along with economic and population growth, have led to increasing global energy demand. In response, in-pipe turbines have gained attention for harnessing hydrokinetic energy from urban water pipelines. Among the various turbine models, vertical-axis drag-based turbines are prevalent in plants with small-diameter pipelines. However, despite recent efforts to identify optimal design of these turbines, the optimization process remains challenging due to the numerous blade profile parameters involved. Accordingly, this paper focuses on introducing a fast and reliable blade shape optimization approach. Firstly, a parametric modeling method is introduced to create different blade geometries. Following this, a theoretical method was developed to calculate the turbine torque coefficient. The reliability of this method was assessed by comparing its results with numerical simulations. The accuracy of the numerical simulations was further validated through experimental tests, revealing a maximum deviation of 6.4 %. Subsequently, a multi-objective optimization technique (NSGA-II) is employed to maximize the turbine's output torque, with the turbine's geometrical features serving as constrains. As a result, the numerical simulations indicated that the proposed design achieved a 40 % increase in torque coefficient and a 38 % improvement in efficiency compared to the conventional model in the bounds of the practical rotational speeds.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"249 ","pages":"Article 123208"},"PeriodicalIF":9.0,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143870827","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

Biodiesel synthesis from Ricinus communis and Pongamia pinnata oil blends by injecting superheated methanol – isopropanol mixtures: Optimization through CCD and ANN approaches

IF 9 1区工程技术 Q1 ENERGY & FUELS

Renewable Energy

Pub Date : 2025-04-20 DOI: 10.1016/j.renene.2025.123223

Bisheswar Karmakar , Sankha Chakrabortty , Ramesh Kumar , Gopinath Halder

In the current study, blends of castor and karanja oils were subjected to uncatalysed alcoholysis with superheated mixtures of 2-propanol and methanol for their rapid conversion into fuel-grade esters. Optimizable ranges identified from batch studies for 6 parameters: alcohol preheat temperature, castor oil to karanja oil ratio, initial oil mass, methanol to 2-propanol ratio, reaction temperature and retention duration were fed into a spherical central composite design (CCD-S, used for identifying process conditions for optimal biodiesel yield. It was noted that a maximum biodiesel yield of 98.79 % could be obtained when 650g castor and karanja oil blend at a ratio of 2:1 was charged into the reactor. The alcohols at a ratio of 3:5 for methanol: 2-proanol had to be pre-heated to 140 °C to achieve desired energy, reactivity and flow. The reaction provided best results when allowed to occur at 260 °C for a duration of 8 min. The experimentally obtained data were verified for reliability through ANOVA studies and ANN was used to validate the data as well as develop a model capable of predicting output accurately, with a 6-10-1 algorithm giving an R² of 0.987, indicating high reliability.

{"title":"Biodiesel synthesis from Ricinus communis and Pongamia pinnata oil blends by injecting superheated methanol – isopropanol mixtures: Optimization through CCD and ANN approaches","authors":"Bisheswar Karmakar , Sankha Chakrabortty , Ramesh Kumar , Gopinath Halder","doi":"10.1016/j.renene.2025.123223","DOIUrl":"10.1016/j.renene.2025.123223","url":null,"abstract":"<div><div>In the current study, blends of castor and karanja oils were subjected to uncatalysed alcoholysis with superheated mixtures of 2-propanol and methanol for their rapid conversion into fuel-grade esters. Optimizable ranges identified from batch studies for 6 parameters: alcohol preheat temperature, castor oil to karanja oil ratio, initial oil mass, methanol to 2-propanol ratio, reaction temperature and retention duration were fed into a spherical central composite design (CCD-S, used for identifying process conditions for optimal biodiesel yield. It was noted that a maximum biodiesel yield of 98.79 % could be obtained when 650g castor and karanja oil blend at a ratio of 2:1 was charged into the reactor. The alcohols at a ratio of 3:5 for methanol: 2-proanol had to be pre-heated to 140 °C to achieve desired energy, reactivity and flow. The reaction provided best results when allowed to occur at 260 °C for a duration of 8 min. The experimentally obtained data were verified for reliability through ANOVA studies and ANN was used to validate the data as well as develop a model capable of predicting output accurately, with a 6-10-1 algorithm giving an R<sup>2</sup> of 0.987, indicating high reliability.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"249 ","pages":"Article 123223"},"PeriodicalIF":9.0,"publicationDate":"2025-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143870828","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

Design optimization of composite wind turbine blade using complete constrained expected improvement-subset simulation optimization

IF 9 1区工程技术 Q1 ENERGY & FUELS

Renewable Energy

Pub Date : 2025-04-19 DOI: 10.1016/j.renene.2025.123187

Yuan-Zhuo Ma , Jia Wei , Wei-Dong Liu , Peng-Peng Zhi , Zhen-Zhou Zhao , Chang Xu , Hong-Shuang Li

Abstract

Design

optimization of the large-scale composite wind turbine blade during conceptual design is one of the key processes of the cost decreasing and benefit increasing for current wind power industry. It however, still remains several key issues, such as lack of a fully parametric process, suffering from a huge computational burden and being easily trapped into local optimum. To remedy these issues, this paper proposes a design optimization method for composite wind turbine blade using Complete Constrained Expected Improvement-Subset Simulation Optimization (CCEI-SSO). A fully parametric Finite Element Analysis (FEA) coded by ANSYS parametric design language of the composite wind turbine blade is firstly proposed, which can be linked to an arbitrary optimization method to form a unified joint simulation framework. To enhance the performance of the optimization process, CCEI-SSO is further proposed, where an adaptive Kriging model leveraging CCEI infill strategy is deeply coupled into each simulation level of SSO to keep balance of optimality and feasibility within very limited number of real FEAs. Inheriting from the random nature within SSO, local optimum is well avoided as well. A case of the design optimization of a 10 MW wind turbine blade is considered to demonstrate the performance of the proposed method.

{"title":"Design optimization of composite wind turbine blade using complete constrained expected improvement-subset simulation optimization","authors":"Yuan-Zhuo Ma , Jia Wei , Wei-Dong Liu , Peng-Peng Zhi , Zhen-Zhou Zhao , Chang Xu , Hong-Shuang Li","doi":"10.1016/j.renene.2025.123187","DOIUrl":"10.1016/j.renene.2025.123187","url":null,"abstract":"<div><div>Abstract</div></div><div><h3>Design</h3><div>optimization of the large-scale composite wind turbine blade during conceptual design is one of the key processes of the cost decreasing and benefit increasing for current wind power industry. It however, still remains several key issues, such as lack of a fully parametric process, suffering from a huge computational burden and being easily trapped into local optimum. To remedy these issues, this paper proposes a design optimization method for composite wind turbine blade using Complete Constrained Expected Improvement-Subset Simulation Optimization (CCEI-SSO). A fully parametric Finite Element Analysis (FEA) coded by ANSYS parametric design language of the composite wind turbine blade is firstly proposed, which can be linked to an arbitrary optimization method to form a unified joint simulation framework. To enhance the performance of the optimization process, CCEI-SSO is further proposed, where an adaptive Kriging model leveraging CCEI infill strategy is deeply coupled into each simulation level of SSO to keep balance of optimality and feasibility within very limited number of real FEAs. Inheriting from the random nature within SSO, local optimum is well avoided as well. A case of the design optimization of a 10 MW wind turbine blade is considered to demonstrate the performance of the proposed method.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"249 ","pages":"Article 123187"},"PeriodicalIF":9.0,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143870826","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

Deploying sustainable hydrochars from food waste as solid fuels: The limits of thermogravimetric analysis to describe true combustion behavior

IF 9 1区工程技术 Q1 ENERGY & FUELS

Renewable Energy

Pub Date : 2025-04-19 DOI: 10.1016/j.renene.2025.123221

Matteo Pecchi , Parvaneh Motiei , James L. Adair , Jacqueline O'Connor , Jillian L. Goldfarb

This work compares fuel science and combustion properties for solid biofuel made via the hydrothermal carbonization (HTC) of food waste (FW). Because HTC of FW produces a hydrochar (HC) that comprises two phases – a solid primary char and an amorphous secondary char that limits fluidization – the HCs are first solvent-extracted to separate the char phases. We investigate the combustion properties of the remaining primary char by coupling TGA with experiments in a Hencken burner instrumented with CH∗ chemiluminescence imaging, particle image velocimetry, and two-color pyrometry. TGA data confirms reduction of hydrochar reactivity by secondary char removal; primary char behaves similarly to Illinois #6 coal under slow oxidation conditions. However, ignition delay time measurements at realistic combustion conditions indicate primary char ignites 4–4.5 times faster than coal, despite their similar ignition and combustion modes. Comparing the results of a TGA-informed combustion model with combustion data highlights the limitations of using thermogravimetry as the sole classifier for suitable biofuels and the necessity of real combustion analysis in assessing the suitability of biofuels combustion or co-combustion in burners that are designed for coals.

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引用次数: 0

Efficient in-situ removal of the trace ammonia in biomass-derived syngas by Fe-K-based biochar nano-catalysts

IF 9 1区工程技术 Q1 ENERGY & FUELS

Renewable Energy

Pub Date : 2025-04-19 DOI: 10.1016/j.renene.2025.123224

Zhihao Yu , Zizhao Guo , Lin Lang , Naixin Zhang , Yang Yu , Jian Wei , Qingjie Ge , Xiuli Yin , Chuangzhi Wu

Trace NH₃ in biomass syngas greatly limited the widespread utilization of biomass gasification. Fe-based catalysts is a popular choice for hot gas cleanup, but with generally poor performance of NH₃ decomposition below 700 °C. In this work, biochar nano-catalysts (BN) was simply prepared by one-step catalytic pyrolysis of herb residues, in which the K promoter efficiently adjust catalytic active sites and nano-sized dispersion of Fe nano-particles (NPs) in biochar. The mechanism of NH₃ decomposition was investigated in He/H₂, and gradually extended to the simulated biomass syngas. The Fe-K-based BN catalyst (Fe-K/BN) achieved NH₃ conversion of 95.2 %, N₂ selectivity of 96.3 %, and 120-h good stability in syngas (at the condition of 550 °C with 20 vol% steam). The superior catalytic performance stems from the stable presence of FeN/Fe₃C active phases. K facilitated carbon deposition removal through steam promotion, while simultaneously inhibiting the reverse water-gas shift reaction to enhance trace NH₃ adsorption in biomass-derived syngas. This work provides a promising strategy to develop a cost-effective and stable catalyst for biomass syngas cleanup.

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引用次数: 0

Machine learning prediction and 4E analysis of PV/T coupled with glass drying chamber system PV/T 与玻璃干燥箱系统的机器学习预测和 4E 分析

IF 9 1区工程技术 Q1 ENERGY & FUELS

Renewable Energy

Pub Date : 2025-04-19 DOI: 10.1016/j.renene.2025.123212

Hao Wengang , Wang Xiyu , Rurui Xue , Gong Ping , Baoyue Wang , Ma Jiajie

In order to maximize the utilization efficiency of solar energy while meeting the drying requirements, the PV/T coupled with glass drying chamber system was firstly proposed and employed to dry lemon slices in this study. The 4E methods and ten drying kinetics models were employed to assess drying performance and drying kinetics of lemon slices, meanwhile, the color variation was analyzed. Furthermore, three machine learning algorithms were selected to forecast the drying chamber temperature, PV electric efficiency, PV/T thermal efficiency, PV/T overall efficiency and moisture ratio. The results shown that Two-term model exhibited the best description under the system and open sun drying. The SEC was 3.55 kW h/kg, and the exergy efficiency of PV/T and drying chamber were 0.9 % and 60.04 %, respectively. The system achieved 59.23 tons in CO₂ mitigation and earned 1184.69 $ in carbon credit over 30yr lifecycle. The economic payback period was 3.59 years. Furthermore, the optimized GRU model was comprehensively evaluated as the superior model, and generalization capability had also been validated with higher values of R². Finally, the values of color variation were 5.83 and 4.94 under the system and open sun drying, respectively.

{"title":"Machine learning prediction and 4E analysis of PV/T coupled with glass drying chamber system","authors":"Hao Wengang , Wang Xiyu , Rurui Xue , Gong Ping , Baoyue Wang , Ma Jiajie","doi":"10.1016/j.renene.2025.123212","DOIUrl":"10.1016/j.renene.2025.123212","url":null,"abstract":"<div><div>In order to maximize the utilization efficiency of solar energy while meeting the drying requirements, the PV/T coupled with glass drying chamber system was firstly proposed and employed to dry lemon slices in this study. The 4E methods and ten drying kinetics models were employed to assess drying performance and drying kinetics of lemon slices, meanwhile, the color variation was analyzed. Furthermore, three machine learning algorithms were selected to forecast the drying chamber temperature, PV electric efficiency, PV/T thermal efficiency, PV/T overall efficiency and moisture ratio. The results shown that Two-term model exhibited the best description under the system and open sun drying. The SEC was 3.55 kW h/kg, and the exergy efficiency of PV/T and drying chamber were 0.9 % and 60.04 %, respectively. The system achieved 59.23 tons in CO<sub>2</sub> mitigation and earned 1184.69 $ in carbon credit over 30yr lifecycle. The economic payback period was 3.59 years. Furthermore, the optimized GRU model was comprehensively evaluated as the superior model, and generalization capability had also been validated with higher values of R<sup>2</sup>. Finally, the values of color variation were 5.83 and 4.94 under the system and open sun drying, respectively.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"249 ","pages":"Article 123212"},"PeriodicalIF":9.0,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143859435","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

Utilization of aromatic plants residual biomass after distillation mixed with wood in solid biofuels production

IF 9 1区工程技术 Q1 ENERGY & FUELS

Renewable Energy

Pub Date : 2025-04-19 DOI: 10.1016/j.renene.2025.123198

Pyrovolos Anestis, Kamperidou Vasiliki

In this study, the potential utilization of industrial distillation residues of aromatic plants (helichrysum, crithmum and lavander) was investigated, through their incorporation into fir wood biomass feedstock for the production of solid biofuels in the form of fuel pellets, in an attempt to find alternative to wood raw materials and new avenues of such wastes management. The raw materials were crushed, processed, and pelletized in various proportions of fir wood, so that the ash content remained within the limits of the residential quality classes. The pellets were characterized in terms of their mechanical, physical, chemical and thermal properties. The results showed that all the produced pellets met the requirements of the standards in terms of calorific value, moisture, bulk density and dimensions. The addition of helichrysum enhanced pellets calorific value, while crithmum and lavender slightly deteriorated it. Pellets containing lavender and helichrysum in high contents and crithmum in low contents indicated significantly higher mechanical durability than pure fir wood pellets. Significant correlations among pellet-properties were revealed. The aromatic plant wastes, mixed with pure wood in appropriate ratios, could contribute to the production of high value-added products of solid biofuels, ensuring improved pellets performance and a sustainable waste management pathway.

本研究调查了芳香植物（ helichrysum、cristum 和 lavander）的工业蒸馏残渣的潜在利用率，将其纳入杉木生物质原料，以燃料颗粒的形式生产固体生物燃料，试图找到木材原料的替代品和此类废物管理的新途径。原材料经过粉碎、加工，并以不同比例的杉木制成颗粒，使灰分含量保持在住宅质量等级的限制范围内。对制粒的机械、物理、化学和热性能进行了鉴定。结果表明，所有生产出的颗粒在热值、水分、体积密度和尺寸方面都符合标准要求。鹤望兰的添加提高了颗粒的热值，而麝香草和薰衣草则略微降低了热值。高含量的薰衣草和鹤顶红以及低含量的麝香颗粒的机械耐久性明显高于纯杉木颗粒。颗粒特性之间存在显著的相关性。芳香植物废料以适当的比例与纯木材混合，有助于生产高附加值的固体生物燃料产品，确保颗粒性能的改善和可持续的废物管理途径。

{"title":"Utilization of aromatic plants residual biomass after distillation mixed with wood in solid biofuels production","authors":"Pyrovolos Anestis, Kamperidou Vasiliki","doi":"10.1016/j.renene.2025.123198","DOIUrl":"10.1016/j.renene.2025.123198","url":null,"abstract":"<div><div>In this study, the potential utilization of industrial distillation residues of aromatic plants (<em>helichrysum, crithmum</em> and <em>lavander</em>) was investigated, through their incorporation into fir wood biomass feedstock for the production of solid biofuels in the form of fuel pellets, in an attempt to find alternative to wood raw materials and new avenues of such wastes management. The raw materials were crushed, processed, and pelletized in various proportions of fir wood, so that the ash content remained within the limits of the residential quality classes. The pellets were characterized in terms of their mechanical, physical, chemical and thermal properties. The results showed that all the produced pellets met the requirements of the standards in terms of calorific value, moisture, bulk density and dimensions. The addition of <em>helichrysum</em> enhanced pellets calorific value, while <em>crithmum</em> and <em>lavender</em> slightly deteriorated it. Pellets containing <em>lavender</em> and <em>helichrysum</em> in high contents and <em>crithmum</em> in low contents indicated significantly higher mechanical durability than pure fir wood pellets. Significant correlations among pellet-properties were revealed. The aromatic plant wastes, mixed with pure wood in appropriate ratios, could contribute to the production of high value-added products of solid biofuels, ensuring improved pellets performance and a sustainable waste management pathway.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"248 ","pages":"Article 123198"},"PeriodicalIF":9.0,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852291","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 simulation and experimental study of ARS for the resourceful utilization of low-grade heat hazards from high-geothermal tunnels

IF 9 1区工程技术 Q1 ENERGY & FUELS

Renewable Energy

Pub Date : 2025-04-19 DOI: 10.1016/j.renene.2025.123209

Liufeng Su , Qixiang Yan , Yifan Yang , Junnan Ren , Minjie Qiao , Yajun Xu

To address the critical challenges posed by high geothermal heat hazards in tunnel construction that threaten worker safety and constrain operational efficiency, this study pioneers the utilization of high-temperature water inrush within the tunnel as a heat source to drive an absorption refrigeration system (ARS), thereby enabling proactive thermal regulation of the construction environment. A steady-state ARS model was established using Simulink to comprehensively analyze the impacts of parameters including heat source water, cooling water, and chilled water on the system's coefficient of performance (COP). The investigation revealed that elevated heat source water temperatures significantly enhance refrigeration performance, while increased cooling water temperatures cause synchronous reductions in both cooling capacity and COP. Chilled water flow rate variations demonstrate negligible effects on COP. Furthermore, an ARS laboratory test platform was constructed and validated through indoor experiments, incorporating environmental parameters from an ongoing high geothermal tunnel project and numerical simulation results. The findings demonstrate excellent agreement between computational predictions and experimental data, confirming the robust adaptability of the designed ARS under the specific tunnel conditions. In summary, this research establishes a theoretical foundation for resourceful utilization of high geothermal heat hazards, contributing to green construction practices and sustainable development in tunneling engineering.

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引用次数: 0

Optimal design of vapor-bypassed heat exchanger for performance improvement of air source heat pump system

IF 9 1区工程技术 Q1 ENERGY & FUELS

Renewable Energy

Pub Date : 2025-04-19 DOI: 10.1016/j.renene.2025.123219

Tong Xiong, Heng Wu, Longxiang Hu, Guoqiang Liu, Gang Yan

The vapor-bypassed technique can bypass part of the vapor inside the evaporator to the evaporator outlet, which can effectively increase the heat transfer rate and reduce the pressure drop. In addition, when the vapor-bypassed technique applied to the outdoor heat exchanger of the air source heat pumps (ASHPs), the affect on both the evaporator and condenser performance should be comprehensively considered. Therefore, this paper proposes the vapor-bypassed heat exchanger for the outdoor heat exchanger of a multi-split ASHP system, aiming to enhance both cooling and heating performance. Firstly, simulation models for the vapor-bypassed evaporator and condenser based on the distributed parameter method was developed to determine the circuitry configuration for optimal comprehensive performance. According to the simulation results, the optimal vapor-bypassed circuitry under four APF conditions is identified as 3-2-9 (RP1-R1-RP2). When the heat transfer capacity of the evaporator simulation model is adjusted from 5.5 to 13.5 kW, the pressure drop of the evaporator using the optimized vapor-bypassed circuitry can be reduced by 23.7–98.8 kPa. Meanwhile, under various cooling conditions, using the optimized circuitry can increase the condenser heat transfer capacity by 42–309 W. Subsequently the experimental results indicated that the annual performance factor (APF) of the vapor-bypassed (VB) system increased by 4.0 %, and the annual energy consumption (AEC) of the VB system decreased by 3.8 %. Furthermore, the number of operating indoor units directly influences VB system performance. Experimental results demonstrated that the system's performance enhancement potential increases progressively as fewer indoor units remain active. Finally, the evaluation of Life Cycle Climate Performance (LCCP) showed that the vapor-bypassed technique could reduce carbon emissions by 2.9 % over the life-cycle of the multi-split ASHP. The contribution of this paper can provide new thoughts for optimizing refrigerant circuitry in ASHPs using vapor-bypassed technique.

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引用次数: 0