Hannah Ross, M. Hall, Daniel R. Herber, J. Jonkman, Athul K. Sundarrajan, T. Tran, A. Wright, D. Zalkind, Nick Johnson
This report describes the ongoing and planned development of the software package CT-Opt (Current/Tidal Optimization), a control co-design modeling tool for marine hydrokinetic turbines. The commercialization of these turbines has faced significant challenges due to the complex, multidisciplinary nature of their design and the extreme environmental conditions of their operation. This project aims to create a modeling tool that will enable the efficient design of robust, cost-competitive hydrokinetic turbine systems. Rather than using traditional optimization methods, CT-Opt combines multiple models across a range of fidelities to enable coupled optimization of the system design and system controller via a control co-design approach. With this method, the parameters that affect system performance are considered more comprehensively at every stage of the design process. The lowest-fidelity, frequency-domain model called by CT-Opt is RAFT (Response Amplitudes of Floating Turbines), which was originally developed by the National Renewable Energy Laboratory (NREL) to model response amplitudes of floating offshore wind turbines. The highest-fidelity, time-domain model is OpenFAST, which was developed by NREL for land-based and offshore wind turbines. As part of the CT-Opt project, new functionalities will be added to RAFT and OpenFAST to enable the accurate simulation of fixed and floating marine hydrokinetic turbines. In addition to expanding the capabilities of RAFT and OpenFAST, new mid-fidelity models will be developed. These models will be based on RAFT and OpenFAST and will consist of linearized, state-space models derived from the fully coupled, nonlinear OpenFAST equations and derivative function surrogate models that approximate the nonlinear system behavior. Each model will be coupled with controllers to allow control co-design methods to be applied both within models and across fidelity levels, enabling efficient system optimization.
{"title":"Development of a Control Co-Design Modeling Tool for Marine Hydrokinetic Turbines","authors":"Hannah Ross, M. Hall, Daniel R. Herber, J. Jonkman, Athul K. Sundarrajan, T. Tran, A. Wright, D. Zalkind, Nick Johnson","doi":"10.1115/imece2022-94483","DOIUrl":"https://doi.org/10.1115/imece2022-94483","url":null,"abstract":"\u0000 This report describes the ongoing and planned development of the software package CT-Opt (Current/Tidal Optimization), a control co-design modeling tool for marine hydrokinetic turbines. The commercialization of these turbines has faced significant challenges due to the complex, multidisciplinary nature of their design and the extreme environmental conditions of their operation. This project aims to create a modeling tool that will enable the efficient design of robust, cost-competitive hydrokinetic turbine systems. Rather than using traditional optimization methods, CT-Opt combines multiple models across a range of fidelities to enable coupled optimization of the system design and system controller via a control co-design approach. With this method, the parameters that affect system performance are considered more comprehensively at every stage of the design process. The lowest-fidelity, frequency-domain model called by CT-Opt is RAFT (Response Amplitudes of Floating Turbines), which was originally developed by the National Renewable Energy Laboratory (NREL) to model response amplitudes of floating offshore wind turbines. The highest-fidelity, time-domain model is OpenFAST, which was developed by NREL for land-based and offshore wind turbines. As part of the CT-Opt project, new functionalities will be added to RAFT and OpenFAST to enable the accurate simulation of fixed and floating marine hydrokinetic turbines. In addition to expanding the capabilities of RAFT and OpenFAST, new mid-fidelity models will be developed. These models will be based on RAFT and OpenFAST and will consist of linearized, state-space models derived from the fully coupled, nonlinear OpenFAST equations and derivative function surrogate models that approximate the nonlinear system behavior. Each model will be coupled with controllers to allow control co-design methods to be applied both within models and across fidelity levels, enabling efficient system optimization.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81313747","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}
Extended human exploration of the Moon requires power and in situ resource utilization (ISRU) capabilities to sustain human life. Meeting this need entails a complex systems integration task that needs physics-based models to support decision making. Exergy analysis includes the effects of both the first and second law of thermodynamics, accounting for irreversible processes and quantifying the useful work that can be extracted from a system. It therefore provides a tool for assessing the performance of diverse systems with consistent metrics that facilitate systems integration. Lunar power and ISRU systems are examples of such complex systems. An exergy-based analysis of the Kilopower Reactor Using Stirling Technology (KRUSTY) power generation system is conducted to assess overall KRUSTY performance. KRUSTY, a part of the Kilopower project, is a nuclear fission and Stirling converter power generation system intended for use in space, with the primary focus on generating power for a lunar base. Daytime exergy efficiency for the KRUSTY system is generally higher than nighttime efficiency due to coupling with the lunar surface temperature. The presented results show that the KRUSTY integrated system efficiency is greater than alternate photovoltaic-based power generation schemes for lunar exploration in most use cases analyzed. This improved performance is due to reduced surface area and radiative forcing of the KRUSTY system during daytime operation. Results also indicate higher exergy efficiency at colder ambient temperatures, allowing transient power draw cases to be created which maximize exergy efficiency by biasing towards nighttime operation.
{"title":"Exergy Analysis of Kilopower Nuclear Reactor Systems for Lunar Power Applications","authors":"Griffin Smith, Phillip Dyer, G. Nelson","doi":"10.1115/imece2022-97023","DOIUrl":"https://doi.org/10.1115/imece2022-97023","url":null,"abstract":"\u0000 Extended human exploration of the Moon requires power and in situ resource utilization (ISRU) capabilities to sustain human life. Meeting this need entails a complex systems integration task that needs physics-based models to support decision making. Exergy analysis includes the effects of both the first and second law of thermodynamics, accounting for irreversible processes and quantifying the useful work that can be extracted from a system. It therefore provides a tool for assessing the performance of diverse systems with consistent metrics that facilitate systems integration. Lunar power and ISRU systems are examples of such complex systems. An exergy-based analysis of the Kilopower Reactor Using Stirling Technology (KRUSTY) power generation system is conducted to assess overall KRUSTY performance. KRUSTY, a part of the Kilopower project, is a nuclear fission and Stirling converter power generation system intended for use in space, with the primary focus on generating power for a lunar base.\u0000 Daytime exergy efficiency for the KRUSTY system is generally higher than nighttime efficiency due to coupling with the lunar surface temperature. The presented results show that the KRUSTY integrated system efficiency is greater than alternate photovoltaic-based power generation schemes for lunar exploration in most use cases analyzed. This improved performance is due to reduced surface area and radiative forcing of the KRUSTY system during daytime operation. Results also indicate higher exergy efficiency at colder ambient temperatures, allowing transient power draw cases to be created which maximize exergy efficiency by biasing towards nighttime operation.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82369076","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}
Nicholas A. Ingarra, Krzysztof (Chris) Kobus, J. Maisonneuve
The objective of this research is to quantify the separate effects of electro-osmotic drag (EOD) and back diffusion (BD) on the net water flow across a proton exchange membrane (PEM) where these effects occur simultaneously. The solution here is to detail a method to decompose the net water flow into component drivers without making assumptions regarding the various coefficients, and instead relying on data mining to isolate the EOD and BD contributions. The net water flow across the membrane is a function of current density and water concentration differences, represented as a surface for which slopes can be determined in the direction of constant current to isolate BD, and constant concentration difference to determine EOD. This method also can be used to determine the hydration state of the membrane as well as determining which EOD and BD coefficient empirical models are valid under certain conditions. With a clearer understanding of net water flow, EOD and BD, the water balance of the fuel cell can be improved which will lead to improved fuel cell operation.
{"title":"A Method to Account for the Effects of Electro-Osmotic Drag and Back Diffusion in PEM Fuel Cells","authors":"Nicholas A. Ingarra, Krzysztof (Chris) Kobus, J. Maisonneuve","doi":"10.1115/imece2022-96013","DOIUrl":"https://doi.org/10.1115/imece2022-96013","url":null,"abstract":"\u0000 The objective of this research is to quantify the separate effects of electro-osmotic drag (EOD) and back diffusion (BD) on the net water flow across a proton exchange membrane (PEM) where these effects occur simultaneously. The solution here is to detail a method to decompose the net water flow into component drivers without making assumptions regarding the various coefficients, and instead relying on data mining to isolate the EOD and BD contributions. The net water flow across the membrane is a function of current density and water concentration differences, represented as a surface for which slopes can be determined in the direction of constant current to isolate BD, and constant concentration difference to determine EOD. This method also can be used to determine the hydration state of the membrane as well as determining which EOD and BD coefficient empirical models are valid under certain conditions. With a clearer understanding of net water flow, EOD and BD, the water balance of the fuel cell can be improved which will lead to improved fuel cell operation.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89586729","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}
M. Costa, Reemal D. Prasad, Muzammil Ali, M. G. M. Khan, Antoine de Ramon N’Yeurt, M. R. Ahmed
Though natural resources are abundantly available for utilization of renewable energy sources, many Pacific Island countries continue to rely on fossil fuels. The use of fossil fuels is known to significantly contribute to climate change. Heavy reliance on fossil fuels also hinders the economic development of most of the Pacific Island Countries. To overcome these issues, the energy sector in Fiji is aiming to generate 100% of the required energy using renewables by 2036. One of the viable options which can contribute to this goal is Ocean Thermal Energy Conversion (OTEC) power. The standard OTEC cycle is a modified Carnot cycle and has low efficiency due to the small temperature difference it works with. In this work, we carried out resource assessment around Fiji to identify potential locations where an OTEC power plant can be installed as well as the conceptual design of a 1 MW net power OTEC plant and the variations in power output due to change in surface seawater temperatures (SSTs). Seawater temperature data (in-situ) between 2012–2022 for three locations were obtained and their seasonal, monthly, and diurnal variations were analysed to study the variation of power generation potential. The analysis shows that during the summer season (November to April), a higher temperature difference is available which results in higher power output and efficiency compared to the winter season. The maximum monthly average temperature difference between the surface and the deep sea (4°C) was recorded for March 2022 with a difference of 25.7°C in Suva. The winter month of August in 2015, had the minimum average temperature difference of 20.1°C in Beqa. The maximum surface temperature recorded during the measurement period was nearly 30.5°C (Suva). The analysis of diurnal variation of hourly averaged temperature showed an interesting trend of essentially constant temperature round the clock with the maximum recorded at 4 am. The net power was calculated for the 3 locations for seasonal, monthly and hourly variations. The net power that was estimated to be 1.15 MW for the maximum monthly average temperature, was reduced by about 63% for the minimum. Similarly, the gross power ranged between 1.7 to 2.4 MW for the temperature range. The net power loss increased from 5% to 16% for a drop in 0.5°C in SST from 30°C to 24°C.
{"title":"Variation of Power Output From an OTEC Power Plant Based on Longterm Sea Surface Temperature Data Analysis","authors":"M. Costa, Reemal D. Prasad, Muzammil Ali, M. G. M. Khan, Antoine de Ramon N’Yeurt, M. R. Ahmed","doi":"10.1115/imece2022-97126","DOIUrl":"https://doi.org/10.1115/imece2022-97126","url":null,"abstract":"\u0000 Though natural resources are abundantly available for utilization of renewable energy sources, many Pacific Island countries continue to rely on fossil fuels. The use of fossil fuels is known to significantly contribute to climate change. Heavy reliance on fossil fuels also hinders the economic development of most of the Pacific Island Countries. To overcome these issues, the energy sector in Fiji is aiming to generate 100% of the required energy using renewables by 2036. One of the viable options which can contribute to this goal is Ocean Thermal Energy Conversion (OTEC) power. The standard OTEC cycle is a modified Carnot cycle and has low efficiency due to the small temperature difference it works with. In this work, we carried out resource assessment around Fiji to identify potential locations where an OTEC power plant can be installed as well as the conceptual design of a 1 MW net power OTEC plant and the variations in power output due to change in surface seawater temperatures (SSTs). Seawater temperature data (in-situ) between 2012–2022 for three locations were obtained and their seasonal, monthly, and diurnal variations were analysed to study the variation of power generation potential. The analysis shows that during the summer season (November to April), a higher temperature difference is available which results in higher power output and efficiency compared to the winter season. The maximum monthly average temperature difference between the surface and the deep sea (4°C) was recorded for March 2022 with a difference of 25.7°C in Suva. The winter month of August in 2015, had the minimum average temperature difference of 20.1°C in Beqa. The maximum surface temperature recorded during the measurement period was nearly 30.5°C (Suva). The analysis of diurnal variation of hourly averaged temperature showed an interesting trend of essentially constant temperature round the clock with the maximum recorded at 4 am. The net power was calculated for the 3 locations for seasonal, monthly and hourly variations. The net power that was estimated to be 1.15 MW for the maximum monthly average temperature, was reduced by about 63% for the minimum. Similarly, the gross power ranged between 1.7 to 2.4 MW for the temperature range. The net power loss increased from 5% to 16% for a drop in 0.5°C in SST from 30°C to 24°C.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88377440","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}
Recently Artificial Neural Networks (ANNs) have been gaining an important role in the analysis of complex power cycles, since they have the potential to reduce the computational effort in designing and control of power plants operating conditions compared to rigorous thermodynamic models. This paper presents a novel methodology for the prediction and optimization of the performance of thermoelectric power plants at design conditions using ANNs. The methodology involves a preliminary study to randomly generate the dataset of input variables (i.e., power plant operating conditions) and evaluate the dataset of output variables (i.e., energy and economic performance indicators) via thermodynamic simulation. Using these datasets, ANNs are trained and validated. Finally, the ability of ANN algorithms to replicate thermodynamic models is assessed in terms of absolute relative errors and coefficient of determination. The proposed methodology is flexible with regard to the type of power plants to be replicated and the extent of the investigation, that can be easily adapted by properly selecting the set of input and output variables. To prove its feasibility, the methodology is applied to a coal-fired power plant and a triple-pressure reheat combined cycle. In both case studies, the methodology provided a very good accuracy in predicting the power plant behavior and optimizing their energy or economic performance.
{"title":"Application of Artificial Neural Network to Predict the Performance of Thermoelectric Power Plants at Design Conditions","authors":"R. Carapellucci, L. Giordano","doi":"10.1115/imece2022-94615","DOIUrl":"https://doi.org/10.1115/imece2022-94615","url":null,"abstract":"\u0000 Recently Artificial Neural Networks (ANNs) have been gaining an important role in the analysis of complex power cycles, since they have the potential to reduce the computational effort in designing and control of power plants operating conditions compared to rigorous thermodynamic models.\u0000 This paper presents a novel methodology for the prediction and optimization of the performance of thermoelectric power plants at design conditions using ANNs. The methodology involves a preliminary study to randomly generate the dataset of input variables (i.e., power plant operating conditions) and evaluate the dataset of output variables (i.e., energy and economic performance indicators) via thermodynamic simulation. Using these datasets, ANNs are trained and validated. Finally, the ability of ANN algorithms to replicate thermodynamic models is assessed in terms of absolute relative errors and coefficient of determination. The proposed methodology is flexible with regard to the type of power plants to be replicated and the extent of the investigation, that can be easily adapted by properly selecting the set of input and output variables.\u0000 To prove its feasibility, the methodology is applied to a coal-fired power plant and a triple-pressure reheat combined cycle. In both case studies, the methodology provided a very good accuracy in predicting the power plant behavior and optimizing their energy or economic performance.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77583306","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}
Taylor Mason, K. S. Choi, A. Soulami, K. Johnson, K. Brooks, N. Karri, V. Joshi
A focus of the U.S. Department of Energy is to improve production yield and reduce the cost of Low Enriched Uranium (LEU)-molybdenum alloy (U-10Mo) monolithic fuel plates that will be replacing High Enriched Uranium (HEU) oxide dispersion fuels used currently in the United States High Performance Research Reactors (USHPRR). One area of improvement is lowering the transverse waviness and longitudinal waviness that can be present within the cold rolled foils following rolling operations. Traditional rolling manufacturing techniques for other metal foils use winders to pull and straighten the foil as it is rolled back and forth to the final thickness. This approach cannot be used to roll thin U-10Mo foils (0.008–0.025″ thick) because only small castings can be rolled due to nuclear criticality safety concerns. As a result, the fuel foils are too short (∼1–2 m in length) to use traditional winders. Therefore, it is crucial to identify other rolling parameters (i.e., roller friction, axial tension load, roller diameter, and roll pass reduction percent) that might reduce transverse waviness and longitudinal waviness in the rolled fuel foil and develop a high-yield, low-cost multi-pass rolling manufacturing process. This report documents a systematic finite element modeling study to investigate the effects of numerous rolling parameters to reduce resulting transverse waviness and longitudinal waviness in the fuel foil during multi-pass rolling of U-10Mo foils. The rolling of a U-10Mo plate with initial dimensions of 1″ × 1″ × 0.048″ is modeled using Abaqus CAE. This rolling is modeled to undergo eight 20% reduction roll passes to a final fuel foil thickness of 0.01″. The elastic-plastic constitutive model of the U-10Mo alloy was input to the fuel foil rolling model. The rollers were modeled as rigid bodies. A comparison of rolling friction coefficients of 0.3 and 0.7 over a wide range of applied axial tension loads were investigated in order to evaluate the effect of using a lubricant during rolling. The effect of roller diameter on the resulting transverse waviness and longitudinal waviness of the fuel foil over a wide range of axial tension loads were also investigated by modeling rollers 7/8″ and 3.75″ in diameter. The results of this systematic finite element method study will aid manufacturers in producing low transverse waviness and reduced longitudinal waviness in U-10Mo fuel foils.
{"title":"Computational Modeling of Multi-Pass Rolling Parameters Effect on Resulting Fuel Foil Shape","authors":"Taylor Mason, K. S. Choi, A. Soulami, K. Johnson, K. Brooks, N. Karri, V. Joshi","doi":"10.1115/imece2022-95081","DOIUrl":"https://doi.org/10.1115/imece2022-95081","url":null,"abstract":"\u0000 A focus of the U.S. Department of Energy is to improve production yield and reduce the cost of Low Enriched Uranium (LEU)-molybdenum alloy (U-10Mo) monolithic fuel plates that will be replacing High Enriched Uranium (HEU) oxide dispersion fuels used currently in the United States High Performance Research Reactors (USHPRR). One area of improvement is lowering the transverse waviness and longitudinal waviness that can be present within the cold rolled foils following rolling operations. Traditional rolling manufacturing techniques for other metal foils use winders to pull and straighten the foil as it is rolled back and forth to the final thickness. This approach cannot be used to roll thin U-10Mo foils (0.008–0.025″ thick) because only small castings can be rolled due to nuclear criticality safety concerns. As a result, the fuel foils are too short (∼1–2 m in length) to use traditional winders. Therefore, it is crucial to identify other rolling parameters (i.e., roller friction, axial tension load, roller diameter, and roll pass reduction percent) that might reduce transverse waviness and longitudinal waviness in the rolled fuel foil and develop a high-yield, low-cost multi-pass rolling manufacturing process. This report documents a systematic finite element modeling study to investigate the effects of numerous rolling parameters to reduce resulting transverse waviness and longitudinal waviness in the fuel foil during multi-pass rolling of U-10Mo foils. The rolling of a U-10Mo plate with initial dimensions of 1″ × 1″ × 0.048″ is modeled using Abaqus CAE. This rolling is modeled to undergo eight 20% reduction roll passes to a final fuel foil thickness of 0.01″. The elastic-plastic constitutive model of the U-10Mo alloy was input to the fuel foil rolling model. The rollers were modeled as rigid bodies. A comparison of rolling friction coefficients of 0.3 and 0.7 over a wide range of applied axial tension loads were investigated in order to evaluate the effect of using a lubricant during rolling. The effect of roller diameter on the resulting transverse waviness and longitudinal waviness of the fuel foil over a wide range of axial tension loads were also investigated by modeling rollers 7/8″ and 3.75″ in diameter. The results of this systematic finite element method study will aid manufacturers in producing low transverse waviness and reduced longitudinal waviness in U-10Mo fuel foils.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"8 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91494490","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}
We investigated the possibility of using various novel nanostructured carbon for control of hydrogen isotopes by exploring the adsorption, reflection, and penetration of hydrogen isotopes using molecular dynamics. Nanometer sized allotropes of nano-carbons have completely changed the research trend in carbon materials, and opened numerous exciting possibilities in many applications. Researchers started to pay attention to carbon nanomaterials when Fullerene C60 was discovered in 1985. The discovery of carbon nanotubes in 1991 and the first isolation of single layer of graphene from graphite in 2004 have encouraged researchers to measure the exciting thermal, electrical, and mechanical properties of these carbon nanomaterials computationally and experimentally. In the present research, we investigate graphene layers and nanostructured carbons with random configurations. The REBO and AIREBO potential are used alongside LAMMPS to simulate tritium interactions with sheets of graphene. Custom MATLAB codes were used to create the graphene structure as well as randomly distribute 100 tritium atoms along a plane above and parallel to the graphene sheet. The tritium atoms are held in place while the graphene sheets undergo multiple stages of equilibration. The velocities of tritium atoms are selected so that incident energies may be 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50, 100, 200, or 500 eV during a single simulation. Reflection is shown to be the dominant interaction at low incident energy. Adsorption rates increase with increasing incident energy until energies reach 5 eV. After 5 eV, adsorption rates decrease as incident energy increases. At incident energies greater than 5 eV, adsorption rates increase with the number of graphene layers. At low incident energies (< 1 eV), no isotopic effects on interactions are observed since the predominant interaction is derived from the force of π electrons. Simulations were performed with different incident angles of tritium. Adsorption rates are always the highest when tritium atoms travel vertically towards graphene (θ = 0°) while they are the lowest when the angle is the largest (θ = 60°) with only a few exceptions (5 eV and 10 eV). AIREBO potential shows a significant difference in adsorption of tritium on graphene from REBO potential. AIREBO potential consistently showed lower adsorption rates and higher reflection rates when compared to REBO potential. The results obtained in this research study will be used to develop novel nanomaterials that can be employed for tritium control.
{"title":"Adsorption of Hydrogen Isotopes on Novel Nanomaterials","authors":"Suheyl Polat, Aaron Stinebaugh, Jungkyu Park","doi":"10.1115/imece2022-96589","DOIUrl":"https://doi.org/10.1115/imece2022-96589","url":null,"abstract":"\u0000 We investigated the possibility of using various novel nanostructured carbon for control of hydrogen isotopes by exploring the adsorption, reflection, and penetration of hydrogen isotopes using molecular dynamics. Nanometer sized allotropes of nano-carbons have completely changed the research trend in carbon materials, and opened numerous exciting possibilities in many applications. Researchers started to pay attention to carbon nanomaterials when Fullerene C60 was discovered in 1985. The discovery of carbon nanotubes in 1991 and the first isolation of single layer of graphene from graphite in 2004 have encouraged researchers to measure the exciting thermal, electrical, and mechanical properties of these carbon nanomaterials computationally and experimentally. In the present research, we investigate graphene layers and nanostructured carbons with random configurations. The REBO and AIREBO potential are used alongside LAMMPS to simulate tritium interactions with sheets of graphene. Custom MATLAB codes were used to create the graphene structure as well as randomly distribute 100 tritium atoms along a plane above and parallel to the graphene sheet. The tritium atoms are held in place while the graphene sheets undergo multiple stages of equilibration. The velocities of tritium atoms are selected so that incident energies may be 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50, 100, 200, or 500 eV during a single simulation. Reflection is shown to be the dominant interaction at low incident energy. Adsorption rates increase with increasing incident energy until energies reach 5 eV. After 5 eV, adsorption rates decrease as incident energy increases. At incident energies greater than 5 eV, adsorption rates increase with the number of graphene layers. At low incident energies (< 1 eV), no isotopic effects on interactions are observed since the predominant interaction is derived from the force of π electrons. Simulations were performed with different incident angles of tritium. Adsorption rates are always the highest when tritium atoms travel vertically towards graphene (θ = 0°) while they are the lowest when the angle is the largest (θ = 60°) with only a few exceptions (5 eV and 10 eV). AIREBO potential shows a significant difference in adsorption of tritium on graphene from REBO potential. AIREBO potential consistently showed lower adsorption rates and higher reflection rates when compared to REBO potential. The results obtained in this research study will be used to develop novel nanomaterials that can be employed for tritium control.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"PP 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84868077","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}
Juseny Moura, A. Ferreira, Carlos Fernandes Costa, Luís Barreiros Martins
In the context of the worldwide high fossil fuels consumption and their environmental and geopolitical consequences, the intensive investment in renewable energy technologies such as solar-thermal, solar PV, wind and hydroelectric has emerged as unavoidable for the next decades energy transition goals. This study objective is the design and analysis of a 3 kWp solar PV system for the irrigation of a one-hectare blueberry plantation in the North of Portugal. To maximize the self-consumption energy, the best match must be achieved between the PV system production profile and the irrigation pumps consumption profile, without the use of a battery. The PVsyst software was used to model the case study, considering the location Typical Meteorological Year data obtained by the commercial program, Meteonorm. The simulation allowed the annual estimation of the electricity available at the inverter outlet, the exported into the National grid and the required from the grid in periods of low production. Finally, the economic feasibility of the project was evaluated, taking into account three operating scenarios. The electricity consumption estimation is 3582 kWh/year from which 71% is expected to be provided by the PV system with an annual production of 4514 kWh. The excess energy that will be injected into the grid corresponds to 1973 kWh/year with 58% corresponding to the winter months when the irrigation system is turned off. The economic analysis concluded that the PV system viability is conditioned by the high investment costs and the adequate dynamic management of the irrigation system.
{"title":"Design and Operational Analysis of a Photovoltaic Irrigation System","authors":"Juseny Moura, A. Ferreira, Carlos Fernandes Costa, Luís Barreiros Martins","doi":"10.1115/imece2022-95967","DOIUrl":"https://doi.org/10.1115/imece2022-95967","url":null,"abstract":"\u0000 In the context of the worldwide high fossil fuels consumption and their environmental and geopolitical consequences, the intensive investment in renewable energy technologies such as solar-thermal, solar PV, wind and hydroelectric has emerged as unavoidable for the next decades energy transition goals. This study objective is the design and analysis of a 3 kWp solar PV system for the irrigation of a one-hectare blueberry plantation in the North of Portugal. To maximize the self-consumption energy, the best match must be achieved between the PV system production profile and the irrigation pumps consumption profile, without the use of a battery.\u0000 The PVsyst software was used to model the case study, considering the location Typical Meteorological Year data obtained by the commercial program, Meteonorm.\u0000 The simulation allowed the annual estimation of the electricity available at the inverter outlet, the exported into the National grid and the required from the grid in periods of low production. Finally, the economic feasibility of the project was evaluated, taking into account three operating scenarios.\u0000 The electricity consumption estimation is 3582 kWh/year from which 71% is expected to be provided by the PV system with an annual production of 4514 kWh. The excess energy that will be injected into the grid corresponds to 1973 kWh/year with 58% corresponding to the winter months when the irrigation system is turned off. The economic analysis concluded that the PV system viability is conditioned by the high investment costs and the adequate dynamic management of the irrigation system.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83655884","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}
Sara Gören, F. Barbosa, Erany D. G. Constantino, H. Puga, J. Teixeira
Concentrated solar thermal (CST) technologies have been considered a promising solution to achieve carbon neutrality by 2050. However, to make CST systems attractive to the international energy sector, their efficiency must be enhanced and low-cost manufacturing processes should be used. In this context, an innovative solar receiver for parabolic-dish solar concentrators is developed in this work, focusing on the improvement of the absorption capacity and heat transfer to the thermal fluid. To enhance solar radiation absorption, a pyramid-shaped texture surface is constructed. In addition, the multiple jet impingement process combined with porous media is applied to ensure high heat transfer rates to the thermal fluid. To evaluate the system efficiency, an experimental setup is developed using a parabolic reflector with a solar tracking system and the flow dynamics of multiple jets impinging on the porous surface is analyzed using Particle Image Velocimetry (PIV). The results show that the tested absorber surface increases the solar absorption efficiency by 6.5 %, compared to the smooth surface. Furthermore, the jet’s flow dynamics and heat transfer analysis shows that the porous surface combined with the air jets increases the heat transfer rate, obtaining optimal values for jets velocities ranging between 5 and 10 ms−1.
{"title":"Integration of Hybrid Porous Casting in Solar Receivers to Increase Solar Systems Efficiency","authors":"Sara Gören, F. Barbosa, Erany D. G. Constantino, H. Puga, J. Teixeira","doi":"10.1115/imece2022-95625","DOIUrl":"https://doi.org/10.1115/imece2022-95625","url":null,"abstract":"\u0000 Concentrated solar thermal (CST) technologies have been considered a promising solution to achieve carbon neutrality by 2050. However, to make CST systems attractive to the international energy sector, their efficiency must be enhanced and low-cost manufacturing processes should be used. In this context, an innovative solar receiver for parabolic-dish solar concentrators is developed in this work, focusing on the improvement of the absorption capacity and heat transfer to the thermal fluid. To enhance solar radiation absorption, a pyramid-shaped texture surface is constructed. In addition, the multiple jet impingement process combined with porous media is applied to ensure high heat transfer rates to the thermal fluid. To evaluate the system efficiency, an experimental setup is developed using a parabolic reflector with a solar tracking system and the flow dynamics of multiple jets impinging on the porous surface is analyzed using Particle Image Velocimetry (PIV). The results show that the tested absorber surface increases the solar absorption efficiency by 6.5 %, compared to the smooth surface. Furthermore, the jet’s flow dynamics and heat transfer analysis shows that the porous surface combined with the air jets increases the heat transfer rate, obtaining optimal values for jets velocities ranging between 5 and 10 ms−1.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91381027","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}
A 50kW class PEMFC and 30kAh battery was evaluated to find a correlation between the stack net power overshoot and the stack temperature for sudden load change. First, a 50kW class PEMFC (Proton Exchange Membrane Fuel Cell) model and a battery model were designed and verified using experimental values. Sensitivity study of Energy Management system strategy was also carried out to find the optimal power ratio of the stack and the battery. Next, net power overshoot of the stack and the temperature data of the stack during a sudden load change were compared. The results show that the main factors affecting the Energy Management System strategy of the stack is the stack temperature.
{"title":"50kW PEMFC Hybrid Energy Management System Driving Strategies","authors":"Younghyeon Kim, Sangseok Yu","doi":"10.1115/imece2022-96020","DOIUrl":"https://doi.org/10.1115/imece2022-96020","url":null,"abstract":"\u0000 A 50kW class PEMFC and 30kAh battery was evaluated to find a correlation between the stack net power overshoot and the stack temperature for sudden load change. First, a 50kW class PEMFC (Proton Exchange Membrane Fuel Cell) model and a battery model were designed and verified using experimental values. Sensitivity study of Energy Management system strategy was also carried out to find the optimal power ratio of the stack and the battery. Next, net power overshoot of the stack and the temperature data of the stack during a sudden load change were compared. The results show that the main factors affecting the Energy Management System strategy of the stack is the stack temperature.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83204425","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：