This article tackles the optimization of crankshaft rotation frequency regulators in high-power diesel generators. These generators play a crucial role in the energy efficiency of standalone cogeneration plants. The research focuses on determining the optimal number of teeth on the measuring gear. This factor is crucial for ensuring frequency regulation stability. Nonlinear pulse control methods were applied, and transient processes were modeled. The results show how the number of teeth impacts the accuracy of sampling frequency measurement and regulation efficiency. The novelty of this work lies in the comprehensive analysis of how gear teeth affect the regulation process. A method for selecting the optimal number of teeth has been developed. This significantly eases the adjustment of regulators and cuts costs in implementing modern electronic control systems. This work has practical implicatiowns for upgrading energy systems based on diesel generators, promising improved energy efficiency, reliability, and longevity.
{"title":"Improving the efficiency of frequency regulation for High-Power diesel generators","authors":"Shchasiana Arhun , Aleksandr Bogajevskiy , Andrii Hnatov , Nadezhda Kunicina","doi":"10.1016/j.ecmx.2024.100785","DOIUrl":"10.1016/j.ecmx.2024.100785","url":null,"abstract":"<div><div>This article tackles the optimization of crankshaft rotation frequency regulators in high-power diesel generators. These generators play a crucial role in the energy efficiency of standalone cogeneration plants. The research focuses on determining the optimal number of teeth on the measuring gear. This factor is crucial for ensuring frequency regulation stability. Nonlinear pulse control methods were applied, and transient processes were modeled. The results show how the number of teeth impacts the accuracy of sampling frequency measurement and regulation efficiency. The novelty of this work lies in the comprehensive analysis of how gear teeth affect the regulation process. A method for selecting the optimal number of teeth has been developed. This significantly eases the adjustment of regulators and cuts costs in implementing modern electronic control systems. This work has practical implicatiowns for upgrading energy systems based on diesel generators, promising improved energy efficiency, reliability, and longevity.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"24 ","pages":"Article 100785"},"PeriodicalIF":7.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The growing demand for renewable energy has generated interest in biofuels as alternatives to fossil fuels. Second-generation biofuels, derived from deoxygenating fats and oils, have garnered a higher level of interest from industry and academia due to their potential for direct replacement of diesel and jet fuels. Palm oil, mostly cultivated in Thailand and composed of C16 and C18 fatty acids, is a primary feedstock sought for biofuel production. Palm oil deoxygenation contains several pathways that may or may not require hydrogen gas. This study aimed to produce biofuels in different fuel ranges, such as gasoline, jet fuel, and diesel, through palm oil deoxygenation using glycerol as a hydrogen source. Glycerol, a low-value byproduct, was used as a hydrogen donor, whereas nickel-molybdenum-supported catalysts were chosen for their high efficiency in deoxygenation and cost-effectiveness. The study investigated the impact of reaction time, temperature, and catalyst activation method on palm oil deoxygenation. Catalyst characterization methods, including XRD, SEM, TEM, XPS, FTIR, TGA, and nitrogen-sorption, were employed to understand the role of catalysts’ activity during palm oil upgrading. Findings indicated that alkane hydrocarbons are the major components in liquid products. The presence of excess hydrogen in post reaction gaseous phase proves the hydrogen donation capability of glycerol. Increased reaction time and temperature facilitated the removal of oxygen from palm oil. Nickel-molybdenum on zirconia activated by sulfidation demonstrated higher stability than by reduction activation.
{"title":"Biofuel production from palm oil deoxygenation using nickel-molybdenum on zirconia catalyst using glycerol as a hydrogen donor","authors":"Nitchakul Hongloi , Tawsif Rahman , Bijoy Biswas , Farshad Feyzbar-Khalkhali-Nejad , Chaiwat Prapainainar , Peerawat Wongsurakul , Pavlo Ivanchenko , Deb P. Jaisi , Emmanuel Aransiola , Lihua Zhang , Mohamed Ammar , Jonas Baltrusaitis , Paweena Prapainainar , Sushil Adhikari","doi":"10.1016/j.ecmx.2024.100781","DOIUrl":"10.1016/j.ecmx.2024.100781","url":null,"abstract":"<div><div>The growing demand for renewable energy has generated interest in biofuels as alternatives to fossil fuels. Second-generation biofuels, derived from deoxygenating fats and oils, have garnered a higher level of interest from industry and academia due to their potential for direct replacement of diesel and jet fuels. Palm oil, mostly cultivated in Thailand and composed of C16 and C18 fatty acids, is a primary feedstock sought for biofuel production. Palm oil deoxygenation contains several pathways that may or may not require hydrogen gas. This study aimed to produce biofuels in different fuel ranges, such as gasoline, jet fuel, and diesel, through palm oil deoxygenation using glycerol as a hydrogen source. Glycerol, a low-value byproduct, was used as a hydrogen donor, whereas nickel-molybdenum-supported catalysts were chosen for their high efficiency in deoxygenation and cost-effectiveness. The study investigated the impact of reaction time, temperature, and catalyst activation method on palm oil deoxygenation. Catalyst characterization methods, including XRD, SEM, TEM, XPS, FTIR, TGA, and nitrogen-sorption, were employed to understand the role of catalysts’ activity during palm oil upgrading. Findings indicated that alkane hydrocarbons are the major components in liquid products. The presence of excess hydrogen in post reaction gaseous phase proves the hydrogen donation capability of glycerol. Increased reaction time and temperature facilitated the removal of oxygen from palm oil. Nickel-molybdenum on zirconia activated by sulfidation demonstrated higher stability than by reduction activation.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"24 ","pages":"Article 100781"},"PeriodicalIF":7.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.ecmx.2024.100787
Muteeb ul Haq , Ali Turab Jafry , Wajahat Ullah Khan , Arslan Ahmed , Muhammad Abdul Ahad , Sattar Jabbar Murad Algayyim , Naseem Abbas , Uzair Sajjad , Khalid Hamid
Biodiesel is a promising alternative to conventional diesel. However, it may cause reduced mass flow, higher injector deposits and poor atomization. This study presents the numerical investigation of the effect of in-nozzle flow on fuel spray behavior for castor methyl ester (CME20) and waste cooking oil methyl ester (WCME20) using two different nozzle hole sizes. Two step simulation methodology was adopted where flow inside the nozzle was simulated first, mass flow rate and velocities at nozzle outlet were used as an input for analyzing the fuel spray in a closed vessel. These simulated results of fuel spray were also validated with experimental results from the captured spray images from control volume spray vessel (CVSV). Experimental spray results were also investigated based on light intensity level and macroscopic spray properties. Results revealed higher cavitation intensity for diesel than biodiesel fuels. Smaller nozzle hole (N2) is more likely to cavitate as compared to larger nozzle diameter (N1). In terms of spray behavior, N1 nozzle on average showed longer penetration length (+1.95 %), wider spray cone angle (+6.2 %) and larger drop diameter (+3.1 %) in comparison to N2. CME20, due to its increased viscosity and density showed longer penetration length (+5.9 %), narrower spray cone angle (−21 %) and reduced spray projected area (−19 %) with respect to diesel. WCME20 revealed smaller sauter mean diameter (−4.8 %) as compared to CME20 owing to its lower viscosity.
{"title":"Investigation of in-nozzle flow behavior coupled with spray characteristics of waste cooking oil and castor biodiesel","authors":"Muteeb ul Haq , Ali Turab Jafry , Wajahat Ullah Khan , Arslan Ahmed , Muhammad Abdul Ahad , Sattar Jabbar Murad Algayyim , Naseem Abbas , Uzair Sajjad , Khalid Hamid","doi":"10.1016/j.ecmx.2024.100787","DOIUrl":"10.1016/j.ecmx.2024.100787","url":null,"abstract":"<div><div>Biodiesel is a promising alternative to conventional diesel. However, it may cause reduced mass flow, higher injector deposits and poor atomization. This study presents the numerical investigation of the effect of in-nozzle flow on fuel spray behavior for castor methyl ester (CME20) and waste cooking oil methyl ester (WCME20) using two different nozzle hole sizes. Two step simulation methodology was adopted where flow inside the nozzle was simulated first, mass flow rate and velocities at nozzle outlet were used as an input for analyzing the fuel spray in a closed vessel. These simulated results of fuel spray were also validated with experimental results from the captured spray images from control volume spray vessel (CVSV). Experimental spray results were also investigated based on light intensity level and macroscopic spray properties. Results revealed higher cavitation intensity for diesel than biodiesel fuels. Smaller nozzle hole (N2) is more likely to cavitate as compared to larger nozzle diameter (N1). In terms of spray behavior, N1 nozzle on average showed longer penetration length (+1.95 %), wider spray cone angle (+6.2 %) and larger drop diameter (+3.1 %) in comparison to N2. CME20, due to its increased viscosity and density showed longer penetration length (+5.9 %), narrower spray cone angle (−21 %) and reduced spray projected area (−19 %) with respect to diesel. WCME20 revealed smaller sauter mean diameter (−4.8 %) as compared to CME20 owing to its lower viscosity.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"24 ","pages":"Article 100787"},"PeriodicalIF":7.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.ecmx.2024.100784
Mohammad Hossein Jahangir , Fatemeh Salmanpour , Erfan Sadeghitabar
Renewable energies, as a sustainable alternative to fossil fuels, confront a twofold challenge characterized by intermittency and the imperative to enhance reliability. Hybrid energy systems (HES) emerge as a pragmatic solution with the potential to mitigate carbon emissions and foster self-sufficiency within local communities. This investigation primarily seeks to ascertain the optimal configuration of a HES integrated with Wavestar wave energy converter, considering economic, technical, and environmental factors, tailored to meet the electricity demands of two cities in Iran including Chabahar and Anzali alongside of the Caspian sea and Oman sea, respectively. For this purpose, HOMER software is used for modeling and optimization the energy systems. In both locations, the optimal system includes photovoltaic (PV), wind turbine (WT), Wavestar wave energy converter (WEC), diesel generator (DG), and batteries which results in cost of energy (COE) of 0.136 and 0.109 in Chabahar and Anzali, respectively. Sensitivity analysis reveals that wind speed significantly impacts COE and reliability, also grid electricity purchases play a vital role. Economic uncertainty highlights varying importance between capital costs for PV and WT in Anzali and Chabahar. Furthermore, this study delves into the limitations posed by the fuel dependency of diesel generators. Finally, by conducting a thorough assessment of solar energy potential by GIS software, the research identifies a favorable location for the establishment of a solar power plant, contributing to the overall feasibility of the proposed hybrid energy systems.
{"title":"Feasibility assessment of using Wavestar energy converter in a grid-connected hybrid renewable energy system (a case study)","authors":"Mohammad Hossein Jahangir , Fatemeh Salmanpour , Erfan Sadeghitabar","doi":"10.1016/j.ecmx.2024.100784","DOIUrl":"10.1016/j.ecmx.2024.100784","url":null,"abstract":"<div><div>Renewable energies, as a sustainable alternative to fossil fuels, confront a twofold challenge characterized by intermittency and the imperative to enhance reliability. Hybrid energy systems (HES) emerge as a pragmatic solution with the potential to mitigate carbon emissions and foster self-sufficiency within local communities. This investigation primarily seeks to ascertain the optimal configuration of a HES integrated with Wavestar wave energy converter, considering economic, technical, and environmental factors, tailored to meet the electricity demands of two cities in Iran including Chabahar and Anzali alongside of the Caspian sea and Oman sea, respectively. For this purpose, HOMER software is used for modeling and optimization the energy systems. In both locations, the optimal system includes photovoltaic (PV), wind turbine (WT), Wavestar wave energy converter (WEC), diesel generator (DG), and batteries which results in cost of energy (COE) of 0.136 and 0.109 in Chabahar and Anzali, respectively. Sensitivity analysis reveals that wind speed significantly impacts COE and reliability, also grid electricity purchases play a vital role. Economic uncertainty highlights varying importance between capital costs for PV and WT in Anzali and Chabahar. Furthermore, this study delves into the limitations posed by the fuel dependency of diesel generators. Finally, by conducting a thorough assessment of solar energy potential by GIS software, the research identifies a favorable location for the establishment of a solar power plant, contributing to the overall feasibility of the proposed hybrid energy systems.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"24 ","pages":"Article 100784"},"PeriodicalIF":7.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.ecmx.2024.100737
Rahat Redwan , Mahmudul Hasan , Awatif Nadia , Md. Sabid Khan , Nishat Anjum Chowdhury , Nahid-Ur-Rahman Chowdhury
Electric vehicles are crucial for sustainable transport and energy solutions, particularly in developing countries like Bangladesh where their popularity is rising. This study primarily focuses on the techno-economic design of a 300 kWp solar photovoltaic-powered electric vehicle charging station along the Dhaka-Mawa Expressway in Bangladesh, capable of charging 20 electric vehicles simultaneously. The design utilizes the commercially available software package PVsyst 7.2 to ensure the feasibility and efficiency of the charging infrastructure. The use of solar photovoltaics for electric vehicle charging, compared to traditional grid-based methods, offers substantial environmental benefits, including significant reductions in carbon emissions. This shift is driven by decreasing costs, improved module efficiencies, and increased environmental awareness. The estimated levelized cost of energy is calculated at 7.1556 BDT/kWh (BDT is Bangladeshi Taka), with an annual energy generation cost of 1436285.32 BDT. Over a projected lifespan of 25 years, the system is expected to replace 8065 tons of CO2 emissions with its own emissions totaling 537.56 tons, resulting in a net decrease of 6460.2 tons of CO2. This approach not only aligns with Bangladesh’s emission reduction goals but also exemplifies the potential for solar photovoltaic systems to enhance sustainability in transportation. It also emphasizes the importance of integrating renewable energy sources into the electric vehicle-based infrastructure to achieve true sustainability and supports the country’s commitment to combating climate change through technological innovation.
{"title":"Design analysis and techno-economic assessment of a photovoltaic-fed electric vehicle charging station at Dhaka-Mawa expressway in Bangladesh","authors":"Rahat Redwan , Mahmudul Hasan , Awatif Nadia , Md. Sabid Khan , Nishat Anjum Chowdhury , Nahid-Ur-Rahman Chowdhury","doi":"10.1016/j.ecmx.2024.100737","DOIUrl":"10.1016/j.ecmx.2024.100737","url":null,"abstract":"<div><div>Electric vehicles are crucial for sustainable transport and energy solutions, particularly in developing countries like Bangladesh where their popularity is rising. This study primarily focuses on the techno-economic design of a 300 kW<sub>p</sub> solar photovoltaic-powered electric vehicle charging station along the Dhaka-Mawa Expressway in Bangladesh, capable of charging 20 electric vehicles simultaneously. The design utilizes the commercially available software package PVsyst 7.2 to ensure the feasibility and efficiency of the charging infrastructure. The use of solar photovoltaics for electric vehicle charging, compared to traditional grid-based methods, offers substantial environmental benefits, including significant reductions in carbon emissions. This shift is driven by decreasing costs, improved module efficiencies, and increased environmental awareness. The estimated levelized cost of energy is calculated at 7.1556 BDT/kWh (BDT is Bangladeshi Taka), with an annual energy generation cost of 1436285.32 BDT. Over a projected lifespan of 25 years, the system is expected to replace 8065 tons of CO<sub>2</sub> emissions with its own emissions totaling 537.56 tons, resulting in a net decrease of 6460.2 tons of CO<sub>2</sub>. This approach not only aligns with Bangladesh’s emission reduction goals but also exemplifies the potential for solar photovoltaic systems to enhance sustainability in transportation. It also emphasizes the importance of integrating renewable energy sources into the electric vehicle-based infrastructure to achieve true sustainability and supports the country’s commitment to combating climate change through technological innovation.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"24 ","pages":"Article 100737"},"PeriodicalIF":7.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.ecmx.2024.100733
Valerio Mariani , Saverio Ottaviano , Davide Scampamorte , Andrea De Pascale , Giulio Cazzoli , Lisa Branchini , Gian Marco Bianchi
This study presents a new design tool for working fluid mixtures in organic Rankine cycles. The proposed tool comprises a blend model for the thermophysical properties of the formulated mixtures, an ORC model to predict the performance of the mixtures in a specific application, and an optimizer based on the Bayesian inference method to identify the optimal mixtures compositions to be assessed. The tool is programmed to optimize an objective function based on predefined optimization targets. Importantly, the targets and their respective weights within the objective function can be adjusted to meet the specific requirements of the application under analysis, making this approach adaptable to diverse research and industrial objectives. The algorithm is applied to a case study to demonstrate its ability to define a low-GWP blend that can replace HFC-134a in a micro-scale ORC with recuperator, while maintaining and potentially enhancing performance. The optimization targets specified for the case study are the net power output, the net efficiency, the GWP and the blend size. Power and efficiency are computed through a validated model of the low-temperature ORC system used as benchmark case. The results showed that the procedure was able to formulate several blends that comply with the targets of the assigned task. Amongst the high-scoring mixtures, the most used pure fluids are R32, R152a, R1234yf, and R1234ze(E). The presence of HCs is limited to fewer mixtures, playing the main role of GWP-limiter. A method to estimate the flammability classification of the blends has been also applied, obtaining that most of them belong to the ASHRAE class 2l, except when an HC is present, in which case the fluid is may result in class 3.
{"title":"Optimal mixture design for organic Rankine cycle using machine learning algorithm","authors":"Valerio Mariani , Saverio Ottaviano , Davide Scampamorte , Andrea De Pascale , Giulio Cazzoli , Lisa Branchini , Gian Marco Bianchi","doi":"10.1016/j.ecmx.2024.100733","DOIUrl":"10.1016/j.ecmx.2024.100733","url":null,"abstract":"<div><div>This study presents a new design tool for working fluid mixtures in organic Rankine cycles. The proposed tool comprises a blend model for the thermophysical properties of the formulated mixtures, an ORC model<!--> <!-->to predict the performance of the mixtures in a specific application, and an optimizer based on the Bayesian inference method to identify the optimal mixtures compositions to be assessed. The tool is programmed to optimize an objective function based on predefined optimization targets. Importantly, the targets and their respective weights within the objective function can be adjusted to meet the specific requirements of the application under analysis, making this approach adaptable to diverse research and industrial objectives. The algorithm is applied to a case study to demonstrate its ability to define a low-GWP blend that can replace HFC-134a in a micro-scale ORC with recuperator, while maintaining and potentially enhancing performance. The optimization targets specified for the case study are the net power output, the net efficiency, the GWP and the blend size. Power and efficiency are computed through a validated model of the low-temperature ORC system used as benchmark case. The results showed that the procedure was able to formulate several blends that comply with the targets of the assigned task. Amongst the high-scoring mixtures, the most used pure fluids are R32, R152a, R1234yf, and R1234ze(E). The presence of HCs is limited to fewer mixtures, playing the main role of GWP-limiter. A method to estimate the flammability classification of the blends has been also applied, obtaining that most of them belong to the ASHRAE class 2l, except when an HC is present, in which case the fluid is may result in class 3.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"24 ","pages":"Article 100733"},"PeriodicalIF":7.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, performance evaluation, drying kinetics modelling and economic analysis of locally manufactured rice husk-fueled mixed-flow rice dryer were investigated. The dryer had a size of 0.4 × 0.4 × 0.64 m (width, length, and height) with a holding capacity of 30 kg in a batch. The drying air used had a volume flow rate of 0.06 m3/s, with an average drying air velocity of 0.62 m/s within the drying section. The average temperature recorded during the experiment was 49.5 ± 3.1℃ at the dryer inlet, while the ambient air temperature was 26.4 ± 0.2℃. The dryer was able to reduce the moisture content of the sample rice from 20.9 % (wet bases) to 12 % (wet bases) in 3 h and 10 min, achieving an average drying rate of 0.076 kg water per minute or 0.016 kg water per kg dry matter per minute. In order to achieve this drying rate, the average energy consumption was 37.9 MJ with an average of 54.29 % dryer efficiency. The Modified Henderson & Pabis was the best drying model to predict the drying kinetics in this study among the different thin-layer drying models. The milling quality of the dry product was assessed using the Head Rice Yield (HRY). The HRY was found to be 57.4 ± 0.62 % for long and slender Nerica-4 rice cultivars, the result was above the required customer requirement which is 55 % and more. Furthermore, the economic analysis indicated that the payback period for the developed rice husk-fueled mixed-flow dryer for drying rice was 1.4 years. The dryer, which costs 64,213ETB (approximately USD 1,230) has the potential to significantly reduce postharvest loss and enhance food security and income of smallholder farmers in rural off-grid areas.
{"title":"Modeling the drying kinetics, performance evaluation, and economic analysis of rice drying using a rice husk-fueled mixed-flow dryer","authors":"Yabebal Chekole Mihret , Solomon Tekeste Hailemesikel , Aschale Getnet Alemu , Mulugeta Admasu Delele","doi":"10.1016/j.ecmx.2024.100774","DOIUrl":"10.1016/j.ecmx.2024.100774","url":null,"abstract":"<div><div>In this study, performance evaluation, drying kinetics modelling and economic analysis of locally manufactured rice husk-fueled mixed-flow rice dryer were investigated. The dryer had a size of 0.4 × 0.4 × 0.64 m (width, length, and height) with a holding capacity of 30 kg in a batch. The drying air used had a volume flow rate of 0.06 m<sup>3</sup>/s, with an average drying air velocity of 0.62 m/s within the drying section. The average temperature recorded during the experiment was 49.5 ± 3.1℃ at the dryer inlet, while the ambient air temperature was 26.4 ± 0.2℃. The dryer was able to reduce the moisture content of the sample rice from 20.9 % (wet bases) to 12 % (wet bases) in 3 h and 10 min, achieving an average drying rate of 0.076 kg water per minute or 0.016 kg water per kg dry matter per minute. In order to achieve this drying rate, the average energy consumption was 37.9 MJ with an average of 54.29 % dryer efficiency. The Modified Henderson & Pabis was the best drying model to predict the drying kinetics in this study among the different thin-layer drying models. The milling quality of the dry product was assessed using the Head Rice Yield (HRY). The HRY was found to be 57.4 ± 0.62 % for long and slender Nerica-4 rice cultivars, the result was above the required customer requirement which is 55 % and more. Furthermore, the economic analysis indicated that the payback period for the developed rice husk-fueled mixed-flow dryer for drying rice was 1.4 years. The dryer, which costs 64,213ETB (approximately USD 1,230) has the potential to significantly reduce postharvest loss and enhance food security and income of smallholder farmers in rural off-grid areas.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"24 ","pages":"Article 100774"},"PeriodicalIF":7.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.ecmx.2024.100760
István Lázár , István Hadnagy , Boglárka Bertalan-Balázs , László Bertalan , Sándor Szegedi
Exact knowledge of wind energy potential is a fundamental issue in wind energy utilization. The vertical changes in wind speeds, that is, the wind profile, have a predominant impact on the wind energy available at a location because the kinetic energy of moving air is proportional to the square of the wind speed. Roughness describes the resistance of a 3D surface to moving air. The exponent α of the power law of Hellmann and the roughness length (z0) are two parameters that describe the effects of the roughness of the surface on the wind profile. They can be used for the vertical extrapolation of wind speeds. The exponent α can be determined using multiple height level wind speed measurement data, whereas a reliable technique for the calculation of the roughness length requires detailed knowledge of the 3D geometry of the measurement site. In the present study, the exponent α was calculated based on SODAR wind speed measurements, while (z0) was determined using a combination of GIS and UAS-based aerial survey methods. Wind speeds measured at 50 m were extrapolated for height levels of 80, 90, 100, 110, and 120 m using dynamic power law exponent values. Wind power was determined using the power law (method V1), roughness length (method V2), frequency distribution (method W-RF), and gamma distribution (method W-G), and Windographer software was compared to the values calculated from the empirical (measured) wind speeds. A comparative statistical analysis of the datasets of the power law and roughness length methods on monthly/diurnal, annual/diurnal, and month/direction contexts showed no significant differences at all height levels. Differences can be detected in the distribution of the signs of the differences at heights of 80 and 120 m for the entire dataset. Underestimation was dominant with a significant frequency (over 70 %) in the case of both methods and heights. There were no significant differences between the wind power estimations provided by the different methods, and all the methods involved in the study underestimated the wind speeds and wind energy potential for each height level. Methods V1 and V2 can be used alternatively, depending on the input data available for analysis. The major advantage of method V2 is that it provides the same accuracy as V1, which requires a UAS-based aerial survey at the beginning, but continuous wind measurements must be performed at a lower height only. This means that there is no need for a high measurement tower, which makes the measurements simpler, more cost-effective, and causes much less disturbance to the environment. Another important advantage of the methods presented here is that they use a dynamic approach of power law exponent values that provide a more realistic estimation of wind speed and energy on a diurnal scale.
{"title":"Comparative examinations of wind speed and energy extrapolation methods using remotely sensed data – A case study from Hungary","authors":"István Lázár , István Hadnagy , Boglárka Bertalan-Balázs , László Bertalan , Sándor Szegedi","doi":"10.1016/j.ecmx.2024.100760","DOIUrl":"10.1016/j.ecmx.2024.100760","url":null,"abstract":"<div><div>Exact knowledge of wind energy potential is a fundamental issue in wind energy utilization. The vertical changes in wind speeds, that is, the wind profile, have a predominant impact on the wind energy available at a location because the kinetic energy of moving air is proportional to the square of the wind speed. Roughness describes the resistance of a 3D surface to moving air. The exponent α of the power law of Hellmann and the roughness length (z<sub>0</sub>) are two parameters that describe the effects of the roughness of the surface on the wind profile. They can be used for the vertical extrapolation of wind speeds. The exponent α can be determined using multiple height level wind speed measurement data, whereas a reliable technique for the calculation of the roughness length requires detailed knowledge of the 3D geometry of the measurement site. In the present study, the exponent α was calculated based on SODAR wind speed measurements, while (z<sub>0</sub>) was determined using a combination of GIS and UAS-based aerial survey methods. Wind speeds measured at 50 m were extrapolated for height levels of 80, 90, 100, 110, and 120 m using dynamic power law exponent values. Wind power was determined using the power law (method V1), roughness length (method V2), frequency distribution (method W-RF), and gamma distribution (method W-G), and Windographer software was compared to the values calculated from the empirical (measured) wind speeds. A comparative statistical analysis of the datasets of the power law and roughness length methods on monthly/diurnal, annual/diurnal, and month/direction contexts showed no significant differences at all height levels. Differences can be detected in the distribution of the signs of the differences at heights of 80 and 120 m for the entire dataset. Underestimation was dominant with a significant frequency (over 70 %) in the case of both methods and heights. There were no significant differences between the wind power estimations provided by the different methods, and all the methods involved in the study underestimated the wind speeds and wind energy potential for each height level. Methods V1 and V2 can be used alternatively, depending on the input data available for analysis. The major advantage of method V2 is that it provides the same accuracy as V1, which requires a UAS-based aerial survey at the beginning, but continuous wind measurements must be performed at a lower height only. This means that there is no need for a high measurement tower, which makes the measurements simpler, more cost-effective, and causes much less disturbance to the environment. Another important advantage of the methods presented here is that they use a dynamic approach of power law exponent values that provide a more realistic estimation of wind speed and energy on a diurnal scale.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"24 ","pages":"Article 100760"},"PeriodicalIF":7.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142539952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.ecmx.2024.100717
Bairi Levi Rakshith , Lazarus Godson Asirvatham , Appadurai Anitha Angeline , Bryan Lancy , J Perinba Selvin Raj , Jefferson Raja Bose , Somchai Wongwises
Flat heat pipes (FHPs) with rectangular groove wick structures fail to sufficiently uplift the working fluid’s liquid meniscus to cover the upper sides of the groove walls due to the vertically flat wall design. This results in the formation of non-evaporative zones, particularly in the evaporator region, leading to elevated wall temperatures at high heat loads. To address this issue, a novel FHP with elliptical grooves as wick is designed and tested across heat loads ranging from 30 to 360 W. Elliptical groove depths of 0.5 mm and 0.7 mm are evaluated and compared to FHPs with rectangular grooves. Results showed that at 360 W, the 0.7 mm depth elliptical grooves resulted in 6.5 % reduction in evaporator wall temperature and 27.8 % reduction in thermal resistance, along with 31.5 % enhancement in effective thermal conductivity compared to rectangular grooves. The curvature of the elliptical grooves, combined with enhanced surface tension effects of the working fluid, efficiently uplifted the liquid meniscus to cover the upper wall of the groove, minimizing non-evaporative zones. Additionally, FHPs with elliptical grooves demonstrated lower entropy generation, indicating higher thermal efficiency. Consequently, FHPs with elliptical groove designs are concluded to be an efficient and suitable solution for the thermal management of miniaturized electronic devices.
采用矩形槽芯结构的扁平热管 (FHP) 由于采用垂直扁平的管壁设计，工作流体的液体半月板无法充分上浮以覆盖槽壁的上侧。这就形成了非蒸发区，尤其是在蒸发器区域，导致在高热负荷下壁温升高。为了解决这个问题，我们设计了一种新型的全功率变流器，采用椭圆形凹槽作为灯芯，并在 30 到 360 W 的热负荷范围内进行了测试。结果表明，在功率为 360 W 时，与矩形凹槽相比，0.7 mm 深的椭圆形凹槽使蒸发器壁温降低了 6.5%，热阻降低了 27.8%，有效热传导率提高了 31.5%。椭圆形凹槽的弧度与工作流体表面张力效应的增强相结合，有效地将液体半月板提升到凹槽上壁，最大限度地减少了非蒸发区。此外，带有椭圆形凹槽的 FHP 产生的熵值较低，表明热效率较高。因此，采用椭圆形凹槽设计的 FHP 是微型电子设备热管理的一种高效、合适的解决方案。
{"title":"Thermal management performance of a novel elliptically grooved flat heat pipe system embedded with internally cooled condenser","authors":"Bairi Levi Rakshith , Lazarus Godson Asirvatham , Appadurai Anitha Angeline , Bryan Lancy , J Perinba Selvin Raj , Jefferson Raja Bose , Somchai Wongwises","doi":"10.1016/j.ecmx.2024.100717","DOIUrl":"10.1016/j.ecmx.2024.100717","url":null,"abstract":"<div><div>Flat heat pipes (FHPs) with rectangular groove wick structures fail to sufficiently uplift the working fluid’s liquid meniscus to cover the upper sides of the groove walls due to the vertically flat wall design. This results in the formation of non-evaporative zones, particularly in the evaporator region, leading to elevated wall temperatures at high heat loads. To address this issue, a novel FHP with elliptical grooves as wick is designed and tested across heat loads ranging from 30 to 360 W. Elliptical groove depths of 0.5 mm and 0.7 mm are evaluated and compared to FHPs with rectangular grooves. Results showed that at 360 W, the 0.7 mm depth elliptical grooves resulted in 6.5 % reduction in evaporator wall temperature and 27.8 % reduction in thermal resistance, along with 31.5 % enhancement in effective thermal conductivity compared to rectangular grooves. The curvature of the elliptical grooves, combined with enhanced surface tension effects of the working fluid, efficiently uplifted the liquid meniscus to cover the upper wall of the groove, minimizing non-evaporative zones. Additionally, FHPs with elliptical grooves demonstrated lower entropy generation, indicating higher thermal efficiency. Consequently, FHPs with elliptical groove designs are concluded to be an efficient and suitable solution for the thermal management of miniaturized electronic devices.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"24 ","pages":"Article 100717"},"PeriodicalIF":7.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142358522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.ecmx.2024.100779
Ghinwa Naeem , Muhammad Asif , Muhammad Khalid
The Fourth Industrial Revolution, driven by Industry 4.0 technologies, is rapidly transforming the Renewable Energy Sector (RES), offering significant benefits across the entire value chain of renewable energy systems. This study contributes to the literature by systematically investigating the role of 13 key Industry 4.0 digital technologies − Smart meters, Smart grids, Artificial Intelligence, Machine Learning, Digital Twin, 3D Printing, Big Data Analytics, Robotics, Sensors, Internet of Things, Cloud computing, Blockchain, and Cyber Security − in terms of their functions, applications, and potential in the RES. It further examines market dynamics, growth trajectories, and policy implications of Industry 4.0 technologies, highlighting the practical applications and challenges encountered in their adoption in RES. Utilizing a mixed-methods approach, which combines a systematic literature review adopting the PRISMA methodology with insights from industry reports and case studies, the study finds that Industry 4.0 technologies play a critical role in enhancing efficiency, cost-effectiveness, and sustainability in areas such as renewable energy systems’ operation, integration, energy production, management, and maintenance. For example, in the case of solar panels, AI-powered systems can optimize energy production and consumption, potentially leading to a 20% increase in efficiency and a 50% reduction in production cost. Furthermore, the study reflects on the challenges faced by the discussed technologies, including interoperability issues, cybersecurity risks, high implementation costs, and potential job displacement. It concludes that addressing these challenges through collaborative efforts and policy interventions is crucial to fully harness the transformative potential of digital technologies in the RES.
{"title":"Industry 4.0 digital technologies for the advancement of renewable energy: Functions, applications, potential and challenges","authors":"Ghinwa Naeem , Muhammad Asif , Muhammad Khalid","doi":"10.1016/j.ecmx.2024.100779","DOIUrl":"10.1016/j.ecmx.2024.100779","url":null,"abstract":"<div><div>The Fourth Industrial Revolution, driven by Industry 4.0 technologies, is rapidly transforming the Renewable Energy Sector (RES), offering significant benefits across the entire value chain of renewable energy systems. This study contributes to the literature by systematically investigating the role of 13 key Industry 4.0 digital technologies − Smart meters, Smart grids, Artificial Intelligence, Machine Learning, Digital Twin, 3D Printing, Big Data Analytics, Robotics, Sensors, Internet of Things, Cloud computing, Blockchain, and Cyber Security − in terms of their functions, applications, and potential in the RES. It further examines market dynamics, growth trajectories, and policy implications of Industry 4.0 technologies, highlighting the practical applications and challenges encountered in their adoption in RES. Utilizing a mixed-methods approach, which combines a systematic literature review adopting the PRISMA methodology with insights from industry reports and case studies, the study finds that Industry 4.0 technologies play a critical role in enhancing efficiency, cost-effectiveness, and sustainability in areas such as renewable energy systems’ operation, integration, energy production, management, and maintenance. For example, in the case of solar panels, AI-powered systems can optimize energy production and consumption, potentially leading to a 20% increase in efficiency and a 50% reduction in production cost. Furthermore, the study reflects on the challenges faced by the discussed technologies, including interoperability issues, cybersecurity risks, high implementation costs, and potential job displacement. It concludes that addressing these challenges through collaborative efforts and policy interventions is crucial to fully harness the transformative potential of digital technologies in the RES.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"24 ","pages":"Article 100779"},"PeriodicalIF":7.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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