According to the United States Department of Energy, waste heat recovery would allow up to a 20% reduction in greenhouse gases (GHG) emission. Most of the waste energy is discharged as a low-grade heat at temperatures less than 250°C. Therefore, the development of new technologies and the enhancement of existing ones to convert low-grade heat into electrical or mechanical energy are of great importance. The working principle of adsorption-desorption heat pumps with cyclic switching between adsorption and desorption is adapted in the proposed heat engine to generate electrical power from low-temperature heat. Thermodynamic analysis of the heat engine cycle is carried out for the pair adsorbant-adsorbent: CO2-activated carbon. Its efficiencies are calculated accepting the ideal gas law and an adsorption-desorption equilibrium at the key points of the cycle. The cycle consists of two isochores and two isotherms like the Stirling engine, but at the same temperature range and without heat regeneration, its thermal efficiency (work per heat supplied) can reach 11.3% vs. 5.0% and specific work 50.7 vs. 3.55 in the latter. The proposed unit has thermal efficiency in the range of Organic Rankine Cycle units and can be utilized in small-scale applications up to 40kWe, where manufacturing cost of turbines or expanders for ORCs increases dramatically. Accounting for quality (temperature) of utilized heat, the proposed cycle’s exergy efficiency, ζex = 34.5% approaches that of water-steam Rankine cycles utilizing natural gas or coal combustion.
根据美国能源部的说法，废热回收将使温室气体(GHG)排放减少20%。大部分废能在低于250°C的温度下作为低品位热量排出。因此，开发新技术和改进现有技术，将低品位的热能转化为电能或机械能是非常重要的。该热机采用吸附-解吸热泵循环切换的工作原理，利用低温热能发电。对CO<sub>2</sub>-活性炭对吸附剂-吸附剂进行热机循环热力学分析。采用理想气体定律和循环关键点的吸附-解吸平衡来计算其效率。与斯特林发动机一样，循环由两条等温线和两条等温线组成，但在相同的温度范围内，在没有热再生的情况下，其热效率(每供热做功)可以达到11.3% vs. 5.0%，比功可以达到50.7 vs. 3.55。该装置具有有机朗肯循环装置范围内的热效率，可用于高达40kWe的小规模应用，其中orc的涡轮机或膨胀器的制造成本急剧增加。考虑到利用热量的质量(温度)，所提出的循环的能源效率<em>ζ<sub>ex</sub></em>= 34.5%接近利用天然气或煤燃烧的水-蒸汽朗肯循环。
{"title":"An Adsorption-Desorption Heat Engine for Power Generation from Waste Heat","authors":"Mikhail Granovskiy","doi":"10.21926/jept.2304034","DOIUrl":"https://doi.org/10.21926/jept.2304034","url":null,"abstract":"According to the United States Department of Energy, waste heat recovery would allow up to a 20% reduction in greenhouse gases (GHG) emission. Most of the waste energy is discharged as a low-grade heat at temperatures less than 250°C. Therefore, the development of new technologies and the enhancement of existing ones to convert low-grade heat into electrical or mechanical energy are of great importance. The working principle of adsorption-desorption heat pumps with cyclic switching between adsorption and desorption is adapted in the proposed heat engine to generate electrical power from low-temperature heat. Thermodynamic analysis of the heat engine cycle is carried out for the pair adsorbant-adsorbent: CO<sub>2</sub>-activated carbon. Its efficiencies are calculated accepting the ideal gas law and an adsorption-desorption equilibrium at the key points of the cycle. The cycle consists of two isochores and two isotherms like the Stirling engine, but at the same temperature range and without heat regeneration, its thermal efficiency (work per heat supplied) can reach 11.3% vs. 5.0% and specific work 50.7 vs. 3.55 in the latter. The proposed unit has thermal efficiency in the range of Organic Rankine Cycle units and can be utilized in small-scale applications up to 40kWe, where manufacturing cost of turbines or expanders for ORCs increases dramatically. Accounting for quality (temperature) of utilized heat, the proposed cycle’s exergy efficiency, <em>ζ<sub>ex</sub></em> = 34.5% approaches that of water-steam Rankine cycles utilizing natural gas or coal combustion.","PeriodicalId":53427,"journal":{"name":"Journal of Nuclear Energy Science and Power Generation Technology","volume":"46 11","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134991903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kesiena Owebor, Smith Otuagoma, Ogheneakpobo Eyenubo, Arthur Uranta, Friday Ukrakpor, Kesiena Ezewu, Ebimene Ebisine
The proper management of sawdust is critical to socioeconomic development. In this research, waste-to-energy has been proposed to utilize sawdust in selected timber markets in Port Harcourt, namely, Illoabuchi Timber Market, Marine Base Timber Market, and Mile 3 Timber Market. A quantitative approach has been taken to estimate the sawdust generation, energy potential, power generation capacities, and pollutant reduction of indiscriminate combustion of sawdust. The findings suggest that, annually, 171 ktons, 42 ktons and 12 ktons of sawdust, respectively, are generated at the Illoabuchi, Marine Base, and Mile 3 timber markets. Also, the annual energy potential of sawdust in each of these timber markets is within 206-3000 TJ, while power generation is within 2.65-42.56 MW. The proposed power generation can serve the energy needs of the timber markets estimated at 10.2 GWh, 2.7 GWh, and 0.7 GWh, respectively, for Illoabuchi, Marine Base, and Mile 3 timber markets, and also provide extra clean energy for their host communities, respectively, at 308.8 GWh, 76 GWh, and 19.2 GWh, annually. Additionally, the study shows the potential for the reduction of pollutants: particulate matter at 5.85-85.5 tons, carbon monoxide at 760.5-11102 tons, sulfur dioxide at 0.59-8.55 tons, and nitrogen oxide at 5.85-85.5 tons. This research can support policy decisions on properly utilizing sawdust in Nigeria and societies with similar waste management challenges.
{"title":"Technical Analysis of Sawdust-to-Power: A Paradigm Shift in Waste Management in a Typical Developing Economy","authors":"Kesiena Owebor, Smith Otuagoma, Ogheneakpobo Eyenubo, Arthur Uranta, Friday Ukrakpor, Kesiena Ezewu, Ebimene Ebisine","doi":"10.21926/jept.2304033","DOIUrl":"https://doi.org/10.21926/jept.2304033","url":null,"abstract":"The proper management of sawdust is critical to socioeconomic development. In this research, waste-to-energy has been proposed to utilize sawdust in selected timber markets in Port Harcourt, namely, Illoabuchi Timber Market, Marine Base Timber Market, and Mile 3 Timber Market. A quantitative approach has been taken to estimate the sawdust generation, energy potential, power generation capacities, and pollutant reduction of indiscriminate combustion of sawdust. The findings suggest that, annually, 171 ktons, 42 ktons and 12 ktons of sawdust, respectively, are generated at the Illoabuchi, Marine Base, and Mile 3 timber markets. Also, the annual energy potential of sawdust in each of these timber markets is within 206-3000 TJ, while power generation is within 2.65-42.56 MW. The proposed power generation can serve the energy needs of the timber markets estimated at 10.2 GWh, 2.7 GWh, and 0.7 GWh, respectively, for Illoabuchi, Marine Base, and Mile 3 timber markets, and also provide extra clean energy for their host communities, respectively, at 308.8 GWh, 76 GWh, and 19.2 GWh, annually. Additionally, the study shows the potential for the reduction of pollutants: particulate matter at 5.85-85.5 tons, carbon monoxide at 760.5-11102 tons, sulfur dioxide at 0.59-8.55 tons, and nitrogen oxide at 5.85-85.5 tons. This research can support policy decisions on properly utilizing sawdust in Nigeria and societies with similar waste management challenges.","PeriodicalId":53427,"journal":{"name":"Journal of Nuclear Energy Science and Power Generation Technology","volume":"4 9","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135391519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fariba Moradipour, Andreas Markert, Thomas Rudszuck, Niklas Röttgen, Gerald Dück, Martin Finsterbusch, Felix Gerbig, Hermann Nirschl, Gisela Guthausen
Charge transfer and mobility are essential for electrochemical processes in batteries, which need to be understood in detail for optimization, especially in the case of all-solid-state batteries. Wide line NMR is well-known in solid-state NMR and allows the quantification of ion mobility in ordered crystalline and amorphous structures. Temperature-dependent 23Na-NMR is sensitive to ion mobility via longitudinal relaxation, but also via line analysis and transverse relaxation. As 23Na is a spin 3/2 nucleus, 23Na-NMR is also susceptible to electric field gradients caused by their nearest neighbor environment and, therefore, reflects not only the mobility of 23Na+ but also the molecular dynamics in the neighborhood, which are investigated in this paper. The named NMR methods were explored to study 23Na+ mobility in the solid electrolytes NaSICON (sodium (Na) Super Ionic CONductor, here Na3.4Zr2Si2.4P0.6O12), the salt NaTFSI (sodium bis(trifluoromethyl sulfonyl)imide), as well as in the polymer-based electrolytes PEO-NaSICON, PEO-NaTFSI, and PEO-NaTFSI-NaSICON.
{"title":"Na<sup>+</sup> Mobility in PEO-Based Composite Solid-State Electrolytes by NMR","authors":"Fariba Moradipour, Andreas Markert, Thomas Rudszuck, Niklas Röttgen, Gerald Dück, Martin Finsterbusch, Felix Gerbig, Hermann Nirschl, Gisela Guthausen","doi":"10.21926/jept.2304032","DOIUrl":"https://doi.org/10.21926/jept.2304032","url":null,"abstract":"Charge transfer and mobility are essential for electrochemical processes in batteries, which need to be understood in detail for optimization, especially in the case of all-solid-state batteries. Wide line NMR is well-known in solid-state NMR and allows the quantification of ion mobility in ordered crystalline and amorphous structures. Temperature-dependent <sup>23</sup>Na-NMR is sensitive to ion mobility via longitudinal relaxation, but also via line analysis and transverse relaxation. As <sup>23</sup>Na is a spin 3/2 nucleus, <sup>23</sup>Na-NMR is also susceptible to electric field gradients caused by their nearest neighbor environment and, therefore, reflects not only the mobility of <sup>23</sup>Na<sup>+</sup> but also the molecular dynamics in the neighborhood, which are investigated in this paper. The named NMR methods were explored to study <sup>23</sup>Na<sup>+</sup> mobility in the solid electrolytes NaSICON (sodium (Na) Super Ionic CONductor, here Na<sub>3.4</sub>Zr<sub>2</sub>Si<sub>2.4</sub>P<sub>0.6</sub>O<sub>12</sub>), the salt NaTFSI (sodium bis(trifluoromethyl sulfonyl)imide), as well as in the polymer-based electrolytes PEO-NaSICON, PEO-NaTFSI, and PEO-NaTFSI-NaSICON.","PeriodicalId":53427,"journal":{"name":"Journal of Nuclear Energy Science and Power Generation Technology","volume":"3 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135936001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
kamal Ismail, Fatima Lino, Jorge Henriquez, Mohamed Teggar, Abdelghani Laouer, Muslum Arici, Amani Benhorma, Daniel Rodríguez
The building sector is rated as a big consumer of electric energy and emissions, responsible for about 40% of final electric energy consumption. As a result, the Paris Agreement 2015 set a goal for buildings and the construction sector to reach a nearly zero-carbon stage by 2050. This urged most countries to create regulations for the construction sector and invest in energy efficiency programs. The present paper aims to present an updated review of building energy-saving solutions and techniques to contribute to carbon emission mitigation in the building sector. The high energy consumption of a building is mainly due to heating and cooling, which is directly related to the thermal properties of the materials used. Natural ventilation and illumination are other aspects that contribute to the high energy consumption. Considering these issues, the review covers energy-efficient construction materials such as mortars, concrete with PCM, new construction materials with PCM such as 3d printing concrete and geopolymer concrete, and bricks usually used in buildings. Also, the review covers the methods and solutions for energy saving for building heating and cooling. Since transparent windows and façades are essential for structures, their thermal and visual performance is crucial. Established and under-development techniques for windows and façades are presented and discussed. Walls and roofs are usually rated at the top of the weak barriers against a building's heat losses and energy gains. The present paper reviews existing and still under research and development techniques to improve the thermal performance of walls and roofs, such as cool roof and cool walls, walls and roofs with phase change materials (PCM), and ventilated walls and ceilings.Some authors’ comments are presented at the end of each topic. Some possible opportunities for future research and developments are also presented.
{"title":"Enhancement Techniques for the Reduction of Heating and Cooling Loads in Buildings: A Review","authors":"kamal Ismail, Fatima Lino, Jorge Henriquez, Mohamed Teggar, Abdelghani Laouer, Muslum Arici, Amani Benhorma, Daniel Rodríguez","doi":"10.21926/jept.2304031","DOIUrl":"https://doi.org/10.21926/jept.2304031","url":null,"abstract":"The building sector is rated as a big consumer of electric energy and emissions, responsible for about 40% of final electric energy consumption. As a result, the Paris Agreement 2015 set a goal for buildings and the construction sector to reach a nearly zero-carbon stage by 2050. This urged most countries to create regulations for the construction sector and invest in energy efficiency programs. The present paper aims to present an updated review of building energy-saving solutions and techniques to contribute to carbon emission mitigation in the building sector. The high energy consumption of a building is mainly due to heating and cooling, which is directly related to the thermal properties of the materials used. Natural ventilation and illumination are other aspects that contribute to the high energy consumption. Considering these issues, the review covers energy-efficient construction materials such as mortars, concrete with PCM, new construction materials with PCM such as 3d printing concrete and geopolymer concrete, and bricks usually used in buildings. Also, the review covers the methods and solutions for energy saving for building heating and cooling. Since transparent windows and façades are essential for structures, their thermal and visual performance is crucial. Established and under-development techniques for windows and façades are presented and discussed. Walls and roofs are usually rated at the top of the weak barriers against a building's heat losses and energy gains. The present paper reviews existing and still under research and development techniques to improve the thermal performance of walls and roofs, such as cool roof and cool walls, walls and roofs with phase change materials (PCM), and ventilated walls and ceilings.Some authors’ comments are presented at the end of each topic. Some possible opportunities for future research and developments are also presented.","PeriodicalId":53427,"journal":{"name":"Journal of Nuclear Energy Science and Power Generation Technology","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135731485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In an electric power system operation, the main goal of economic dispatch (ED) is to schedule the power outputs of committed generating units efficiently. This involves consideration of relevant system equality and inequality constraints to meet the required power demand at the lowest possible operational cost. This is a challenging optimization problem for power system operators that can be dealt with efficient meta-heuristic algorithms. This article uses a recent meta-heuristic approach named the generalized normal distribution optimization (GNDO) algorithm to achieve near-optimal solutions. The efficacy of the proposed GNDO algorithm is validated through experimentation on three distinct test power system networks: one with three thermal units, the second one with six thermal-unit, and the third one with ten thermal units. The algorithm's performance is also assessed on a power network with renewable energy sources. All analyses of the four test cases are conducted on the MATLAB/SIMULINK platform. Finally, this article also compares the obtained results with other literature-reported strategies, genetic algorithm (GA), particle swarm optimization (PSO), whale optimization algorithm (WOA), flower pollination algorithm (FPA), and bald eagle search (BES) algorithm. It is evident from the simulated cases that the employed GNDO algorithm exhibits superior performance for two cases and competitive performance for the remaining cases in achieving the lowest operation costs and power losses.
{"title":"Generalized Normal Distribution Optimization Algorithm for Economic Dispatch with Renewable Resources Integration","authors":"Sadmanul Hoque, Md. Rashidul Islam, Md Shafiullah, Saymun Adnan, Md Samiul Azam","doi":"10.21926/jept.2303030","DOIUrl":"https://doi.org/10.21926/jept.2303030","url":null,"abstract":"In an electric power system operation, the main goal of economic dispatch (ED) is to schedule the power outputs of committed generating units efficiently. This involves consideration of relevant system equality and inequality constraints to meet the required power demand at the lowest possible operational cost. This is a challenging optimization problem for power system operators that can be dealt with efficient meta-heuristic algorithms. This article uses a recent meta-heuristic approach named the generalized normal distribution optimization (GNDO) algorithm to achieve near-optimal solutions. The efficacy of the proposed GNDO algorithm is validated through experimentation on three distinct test power system networks: one with three thermal units, the second one with six thermal-unit, and the third one with ten thermal units. The algorithm's performance is also assessed on a power network with renewable energy sources. All analyses of the four test cases are conducted on the MATLAB/SIMULINK platform. Finally, this article also compares the obtained results with other literature-reported strategies, genetic algorithm (GA), particle swarm optimization (PSO), whale optimization algorithm (WOA), flower pollination algorithm (FPA), and bald eagle search (BES) algorithm. It is evident from the simulated cases that the employed GNDO algorithm exhibits superior performance for two cases and competitive performance for the remaining cases in achieving the lowest operation costs and power losses.","PeriodicalId":53427,"journal":{"name":"Journal of Nuclear Energy Science and Power Generation Technology","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135344130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the context of decarbonization efforts, heat pump water heaters (HPWHs) offer an attractive solution over conventional electric resistance type hot water systems due to their 2-3 times higher efficiency. However, the high manufacturing costs and taxes associated with using hydrofluorocarbon (HFC) refrigerant make HPWHs expensive. As a means to tackle this issue, this paper explores the use of propane (R290) as a refrigerant in HPWHs. The study involves an experimental comparison of R290 and R134a, with refrigerant charges optimized for the unit at different ambient temperatures. This current work demonstrates that R290 achieves a 10% improvement in coefficient of performance (COP) at ambient temperatures beyond 20°C. However, at 10°C ambient temperature, the study shows that R290 offers no advantage over R134a, and the COP is lower. These results indicate that the compressor is the largest source of inefficiency, and this aligns well with experimental results on system performance. Additionally, simulation tests using compressors designed for R290 did not predict better COP values than the test unit. Overall, the study suggests that R290 is a viable refrigerant option for HPWHs, but further research is necessary to optimize it’s use.
{"title":"A Comparative Study of R134a and Propane (R290) as Refrigerants in Heat Pump Water Heaters","authors":"Ann Lee, Shaokoon Cheng","doi":"10.21926/jept.2303029","DOIUrl":"https://doi.org/10.21926/jept.2303029","url":null,"abstract":"In the context of decarbonization efforts, heat pump water heaters (HPWHs) offer an attractive solution over conventional electric resistance type hot water systems due to their 2-3 times higher efficiency. However, the high manufacturing costs and taxes associated with using hydrofluorocarbon (HFC) refrigerant make HPWHs expensive. As a means to tackle this issue, this paper explores the use of propane (R290) as a refrigerant in HPWHs. The study involves an experimental comparison of R290 and R134a, with refrigerant charges optimized for the unit at different ambient temperatures. This current work demonstrates that R290 achieves a 10% improvement in coefficient of performance (COP) at ambient temperatures beyond 20°C. However, at 10°C ambient temperature, the study shows that R290 offers no advantage over R134a, and the COP is lower. These results indicate that the compressor is the largest source of inefficiency, and this aligns well with experimental results on system performance. Additionally, simulation tests using compressors designed for R290 did not predict better COP values than the test unit. Overall, the study suggests that R290 is a viable refrigerant option for HPWHs, but further research is necessary to optimize it’s use.","PeriodicalId":53427,"journal":{"name":"Journal of Nuclear Energy Science and Power Generation Technology","volume":"122 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135201964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mahdi Yousefi, Scott Donne, Shabnam Bahremand, Mohammad Yousefi
The thermal cracking of methane (TMC) is a significant reaction occurring above 850°C, which proceeds in two stages: non-isothermally and isothermally. However, most existing studies have focused on obtaining reaction rates under isothermal conditions [1], limiting their applicability to practical industrial reactor conditions. This novel research aims to determine the overall thermal decomposition rate of methane to hydrogen and carbon in adiabatic conditions, covering the range of unstable industrial reactor temperatures (850 to 1200°C). The Coats and Redfern model-fitting method was employed to calculate the reaction rate under non-isothermal conditions, and the resulting models were compared with experimental data. The findings reveal the Contracting Cylinder model as the best-fit mathematical representation with less than ±2.8% error. By extending the kinetic model to non-isothermal conditions, this approach addresses a critical aspect of real-world applications.
{"title":"Overall Reaction Rate Study of Thermal Methane Cracking in Non-Isothermal Conditions","authors":"Mahdi Yousefi, Scott Donne, Shabnam Bahremand, Mohammad Yousefi","doi":"10.21926/jept.2303028","DOIUrl":"https://doi.org/10.21926/jept.2303028","url":null,"abstract":"The thermal cracking of methane (TMC) is a significant reaction occurring above 850°C, which proceeds in two stages: non-isothermally and isothermally. However, most existing studies have focused on obtaining reaction rates under isothermal conditions [1], limiting their applicability to practical industrial reactor conditions. This novel research aims to determine the overall thermal decomposition rate of methane to hydrogen and carbon in adiabatic conditions, covering the range of unstable industrial reactor temperatures (850 to 1200°C). The Coats and Redfern model-fitting method was employed to calculate the reaction rate under non-isothermal conditions, and the resulting models were compared with experimental data. The findings reveal the Contracting Cylinder model as the best-fit mathematical representation with less than ±2.8% error. By extending the kinetic model to non-isothermal conditions, this approach addresses a critical aspect of real-world applications.","PeriodicalId":53427,"journal":{"name":"Journal of Nuclear Energy Science and Power Generation Technology","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135690061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Buildings, with their significant energy consumption, pose a pressing concern for the future. Inadequate heating, ventilation, and air-conditioning (HVAC) systems further exacerbate thermal management difficulties and energy requirements. To address these challenges, Phase Change Materials (PCMs) offer valuable potential for sustainable energy reduction within the building sector, leveraging passive cooling and heating techniques. Numerical study has been conducted to explore the impact of embedding PCM within the building envelope on energy efficiency and thermal performance. The results reveal that PCM integration significantly reduces temperatures across all sections compared to scenarios without PCM. By passively absorbing and storing heat energy during phase change, PCM mitigates heat transfer through convection and conduction, leading to improved energy efficiency and reduced power consumption for cooling and heating purposes. Within the first 2 hours, the PCM achieves 50% of its average melting process, followed by a gradual decrease in the melting rate. It takes approximately 6 hours for the PCM to completely melt. As the PCM undergoes the melting process, the system's entropy values increase, reflecting an increase in disorder. At the tip of the building, the entropy value reaches 130 K/kg·K, which is more than three times the initial value. The integration of PCM in building envelopes shows promising potential for enhancing energy efficiency, thermal comfort, and durability. Future research should focus on optimizing PCM placement and configuration to maximize its benefits in diverse building designs and climatic conditions.
{"title":"Exploring the Potential of Phase Change Material for Thermal Energy Storage in Building Envelopes","authors":"Zachary Brozzesi, Darson Dezheng Li, Ann Lee","doi":"10.21926/jept.2303027","DOIUrl":"https://doi.org/10.21926/jept.2303027","url":null,"abstract":"Buildings, with their significant energy consumption, pose a pressing concern for the future. Inadequate heating, ventilation, and air-conditioning (HVAC) systems further exacerbate thermal management difficulties and energy requirements. To address these challenges, Phase Change Materials (PCMs) offer valuable potential for sustainable energy reduction within the building sector, leveraging passive cooling and heating techniques. Numerical study has been conducted to explore the impact of embedding PCM within the building envelope on energy efficiency and thermal performance. The results reveal that PCM integration significantly reduces temperatures across all sections compared to scenarios without PCM. By passively absorbing and storing heat energy during phase change, PCM mitigates heat transfer through convection and conduction, leading to improved energy efficiency and reduced power consumption for cooling and heating purposes. Within the first 2 hours, the PCM achieves 50% of its average melting process, followed by a gradual decrease in the melting rate. It takes approximately 6 hours for the PCM to completely melt. As the PCM undergoes the melting process, the system's entropy values increase, reflecting an increase in disorder. At the tip of the building, the entropy value reaches 130 K/kg·K, which is more than three times the initial value. The integration of PCM in building envelopes shows promising potential for enhancing energy efficiency, thermal comfort, and durability. Future research should focus on optimizing PCM placement and configuration to maximize its benefits in diverse building designs and climatic conditions.","PeriodicalId":53427,"journal":{"name":"Journal of Nuclear Energy Science and Power Generation Technology","volume":"109 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76684171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Shimomukai, Haruka Maeda, Zahirah binti Muhammad Azman, Sandro Sitompul, G. Fujita
One way to increase solar photovoltaic penetration in the grid is the management of voltage fluctuations. This is because a photovoltaic plant cannot be interconnected to the grid if it causes voltage violations. Voltage violation is where voltage exceeds the acceptable range. Often, grid operators request photovoltaic plant owners to regulate voltage sufficiently with expensive and space-consuming static Var compensators. Unfortunately, this sometimes makes the project less feasible. This paper argues that there are better ways to regulate voltage. It also asserts that these ways must be sought before blindly procuring a static Var compensator or seeking battery storage. We simulated with a 70-MW photovoltaic plant as an addition to the grid. Without voltage regulation, voltage violations in Spring were found to be particularly significant. However, the proposed reactive power compensation removed all voltage violations smartly. Furthermore, the study results demonstrated that the operator-induced curtailment effectively reduced the necessary amount of reactive power compensation, leading to a smaller size of SVC, as it occurred specifically at certain overvoltage points. This paper argues that the economic and spatial efficiency of reactive power compensation devices is key to increasing photovoltaic penetration. It argues that one-sided bearing of the cost of reactive compensation devices is inefficient.
{"title":"Volt-Var Control for Utility-Scale Solar PV Plants to Downsize SVCs and Curtailment Effects","authors":"K. Shimomukai, Haruka Maeda, Zahirah binti Muhammad Azman, Sandro Sitompul, G. Fujita","doi":"10.21926/jept.2303026","DOIUrl":"https://doi.org/10.21926/jept.2303026","url":null,"abstract":"One way to increase solar photovoltaic penetration in the grid is the management of voltage fluctuations. This is because a photovoltaic plant cannot be interconnected to the grid if it causes voltage violations. Voltage violation is where voltage exceeds the acceptable range. Often, grid operators request photovoltaic plant owners to regulate voltage sufficiently with expensive and space-consuming static Var compensators. Unfortunately, this sometimes makes the project less feasible. This paper argues that there are better ways to regulate voltage. It also asserts that these ways must be sought before blindly procuring a static Var compensator or seeking battery storage. We simulated with a 70-MW photovoltaic plant as an addition to the grid. Without voltage regulation, voltage violations in Spring were found to be particularly significant. However, the proposed reactive power compensation removed all voltage violations smartly. Furthermore, the study results demonstrated that the operator-induced curtailment effectively reduced the necessary amount of reactive power compensation, leading to a smaller size of SVC, as it occurred specifically at certain overvoltage points. This paper argues that the economic and spatial efficiency of reactive power compensation devices is key to increasing photovoltaic penetration. It argues that one-sided bearing of the cost of reactive compensation devices is inefficient.","PeriodicalId":53427,"journal":{"name":"Journal of Nuclear Energy Science and Power Generation Technology","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72923929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The paper analyses the performance of a spherical solar collector compared to the efficiency of a flat-plate solar collector, which is the type of solar collector that does not use a tracking system in collecting solar radiation for energy conversion. Spherical solar collector benefits from a constant value of the angle of incidence, which optimizes the solar radiation that strikes the absorber of the solar device and maximizes the energy collection. Besides, the spherical geometry has a larger area for equal dimensions, width, and length. The combined effect of a larger surface and a higher value of the effective solar radiation onto the surface of the absorber increases the energy collection and the performance of the solar device. We developed a theoretical analysis to obtain the algorithm to determine the collected solar energy, which increases when using the spherical solar collector. A simulation runs to calculate the predicted values. We developed experimental tests in a spherical solar collector of 1.05 m in diameter, and in a flat-plate solar collector of 1.94 m × 1.025 m. to validate the simulation. The comparative analysis shows that a spherical solar collector generates more energy than a flat-plate one of the same absorbing surface by a factor of 2.09, and 7.75 times more if the width and height of the flat-plate collector equals the diameter of the spherical one.
本文分析了球形太阳能集热器的性能，并与平板太阳能集热器的效率进行了比较，平板太阳能集热器是一种不使用跟踪系统收集太阳辐射进行能量转换的太阳能集热器。球形太阳能集热器受益于一个恒定的入射角值，它优化了太阳辐射撞击太阳能装置的吸收器，最大限度地提高了能量收集。此外，球面几何具有更大的面积等尺寸，宽度和长度。较大的表面和较高的有效太阳辐射值对吸收器表面的综合作用增加了能量收集和太阳能装置的性能。通过理论分析，得到了确定球形太阳能集热器增加的太阳能集热器的算法。通过模拟来计算预测值。我们在直径1.05 m的球形太阳能集热器和1.94 m × 1.025 m的平板太阳能集热器上进行了实验测试，以验证模拟的有效性。对比分析表明，在相同的吸收面下，球形集热器比平板集热器产生的能量多2.09倍，当平板集热器的宽度和高度等于球形集热器的直径时，其产生的能量多7.75倍。
{"title":"Study and Characterization of a Spherical Solar Collector. Part II: Comparative Analysis with Flat-Plate Devices","authors":"C. Armenta-Déu","doi":"10.21926/jept.2303025","DOIUrl":"https://doi.org/10.21926/jept.2303025","url":null,"abstract":"The paper analyses the performance of a spherical solar collector compared to the efficiency of a flat-plate solar collector, which is the type of solar collector that does not use a tracking system in collecting solar radiation for energy conversion. Spherical solar collector benefits from a constant value of the angle of incidence, which optimizes the solar radiation that strikes the absorber of the solar device and maximizes the energy collection. Besides, the spherical geometry has a larger area for equal dimensions, width, and length. The combined effect of a larger surface and a higher value of the effective solar radiation onto the surface of the absorber increases the energy collection and the performance of the solar device. We developed a theoretical analysis to obtain the algorithm to determine the collected solar energy, which increases when using the spherical solar collector. A simulation runs to calculate the predicted values. We developed experimental tests in a spherical solar collector of 1.05 m in diameter, and in a flat-plate solar collector of 1.94 m × 1.025 m. to validate the simulation. The comparative analysis shows that a spherical solar collector generates more energy than a flat-plate one of the same absorbing surface by a factor of 2.09, and 7.75 times more if the width and height of the flat-plate collector equals the diameter of the spherical one.","PeriodicalId":53427,"journal":{"name":"Journal of Nuclear Energy Science and Power Generation Technology","volume":"87 7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81229177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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