Waste heat recovery is a broadly considered opportunity for efficiency improvement in several energy consumption sectors, intending to reduce energy consumption and related carbon dioxide emissions to the atmosphere. The attention of research activities is focused on transportation and residential sectors, where the possible recovery is characterized by low enthalpy, but with a wider potential market. Therefore, the maximization of recovery is one of the principal aims of this option, and different kinds of technologies have been proposed in this regard. Thermodynamic cycles, which exploit the waste heat considering it as the upper thermal source, seem to be a promising option, and the possibility to combine two different cycles can increase the thermal power harvested. In this paper, a combination of a supercritical CO2 Brayton cycle with an ORC-based unit has been proposed to recover waste heat from the exhaust gases of an internal combustion engine for the transportation sector. Using CO2 as working fluid is under investigation in literature, for its low Global Warming Potential and its suitable thermodynamic characteristics in dense phase (just above the critical point). An Organic Rankine Cycle (ORC), then, has been bottomed to the CO2 section, to further recover thermal energy and convert it into mechanical useful work. Indeed, the CO2 cycle must have a lower temperature cold sink, where thermal power can be furtherly recovered. The introduction of this second stage of recovery interacts with the upper one, modifying the overall optimization parameters. Hence, this work aims to find the maximization of the recovery from a global point-of-view, identifying possible trade-offs happenings between the two recovery sections. Minimum sCO2 pressure, stack exhaust temperature, and the possibility to have a regeneration stage have been considered as optimizing parameters. Finally, the optimized system has been applied to a specific mission profile of a commercial vehicle, in order to evaluate the recovery potential during a realistic engine working points sequence. A recovery higher than 4% in every mission considered has been achieved, with values up to 7% in motorway and long-hauling conditions.
{"title":"Optimization of Supercritical CO2 Cycle Combined With ORC for Waste Heat Recovery","authors":"R. Carapellucci, D. Di Battista","doi":"10.1115/imece2022-95106","DOIUrl":"https://doi.org/10.1115/imece2022-95106","url":null,"abstract":"\u0000 Waste heat recovery is a broadly considered opportunity for efficiency improvement in several energy consumption sectors, intending to reduce energy consumption and related carbon dioxide emissions to the atmosphere. The attention of research activities is focused on transportation and residential sectors, where the possible recovery is characterized by low enthalpy, but with a wider potential market. Therefore, the maximization of recovery is one of the principal aims of this option, and different kinds of technologies have been proposed in this regard. Thermodynamic cycles, which exploit the waste heat considering it as the upper thermal source, seem to be a promising option, and the possibility to combine two different cycles can increase the thermal power harvested.\u0000 In this paper, a combination of a supercritical CO2 Brayton cycle with an ORC-based unit has been proposed to recover waste heat from the exhaust gases of an internal combustion engine for the transportation sector. Using CO2 as working fluid is under investigation in literature, for its low Global Warming Potential and its suitable thermodynamic characteristics in dense phase (just above the critical point). An Organic Rankine Cycle (ORC), then, has been bottomed to the CO2 section, to further recover thermal energy and convert it into mechanical useful work. Indeed, the CO2 cycle must have a lower temperature cold sink, where thermal power can be furtherly recovered. The introduction of this second stage of recovery interacts with the upper one, modifying the overall optimization parameters. Hence, this work aims to find the maximization of the recovery from a global point-of-view, identifying possible trade-offs happenings between the two recovery sections. Minimum sCO2 pressure, stack exhaust temperature, and the possibility to have a regeneration stage have been considered as optimizing parameters.\u0000 Finally, the optimized system has been applied to a specific mission profile of a commercial vehicle, in order to evaluate the recovery potential during a realistic engine working points sequence. A recovery higher than 4% in every mission considered has been achieved, with values up to 7% in motorway and long-hauling conditions.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"54 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74688452","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}
Alex Callinan, H. Najafi, A. Fabregas, Troy V. Nguyen
Water treatment plants are responsible for over 30 terawatt-hours per year of electricity consumption in the United States with an annual cost of nearly $2 billion [1]. Understanding the energy consumption in water treatment plants as well as the potential energy efficiency measures (EEMs) for these facilities can help the municipalities to prioritize the relevant energy efficiency projects based on their payback period and potential impact on their energy bill. In the present paper, the energy performance data for 192 water treatment plants is obtained from the U.S. Department of Energy Industrial Assessment Center (IAC) database. Energy audits were performed in these 192 sites between 2009 and 2022. The database includes the approximate location, square footage, annual energy use, annual plant production, identified EEMs, and their associated energy/cost savings as well as estimated payback period. The annual energy consumed per unit of production (EUP) and per unit of plant area (EUI) are calculated. The mean EUI and EUP for all the plants are found as 267.32 kBTU/ft2/Year and 265.97 kBTU/Thousand Gallons/Year, respectively. Also, the median EUI and EUP are evaluated as 42.4776 kBTU/ft2/Year and 8.203 kBTU/Thousand Gallons/Year, respectively. The analysis is also extended to understand the most promising EEMs for water treatment plants. An artificial neural network (ANN) is then developed to facilitate energy forecasting of water treatment plants using basic inputs including plant area and annual production. The outputs include estimated annual energy consumption and estimated potential savings that can be identified through conducting an energy audit. The training, testing and validation was satisfactory, but expected to much improve in the future with the addition of more assessment data to the IAC database. The ANN model will be the core of a basic energy analysis tool that can help the municipalities to easily evaluate the performance of their water treatment plants and estimate the potential savings that may be achieved as the result of performing an energy audit.
{"title":"A Data Driven Analysis on the Energy Performance and Efficiency of Water Treatment Plants","authors":"Alex Callinan, H. Najafi, A. Fabregas, Troy V. Nguyen","doi":"10.1115/imece2022-96040","DOIUrl":"https://doi.org/10.1115/imece2022-96040","url":null,"abstract":"Water treatment plants are responsible for over 30 terawatt-hours per year of electricity consumption in the United States with an annual cost of nearly $2 billion [1]. Understanding the energy consumption in water treatment plants as well as the potential energy efficiency measures (EEMs) for these facilities can help the municipalities to prioritize the relevant energy efficiency projects based on their payback period and potential impact on their energy bill. In the present paper, the energy performance data for 192 water treatment plants is obtained from the U.S. Department of Energy Industrial Assessment Center (IAC) database. Energy audits were performed in these 192 sites between 2009 and 2022. The database includes the approximate location, square footage, annual energy use, annual plant production, identified EEMs, and their associated energy/cost savings as well as estimated payback period. The annual energy consumed per unit of production (EUP) and per unit of plant area (EUI) are calculated. The mean EUI and EUP for all the plants are found as 267.32 kBTU/ft2/Year and 265.97 kBTU/Thousand Gallons/Year, respectively. Also, the median EUI and EUP are evaluated as 42.4776 kBTU/ft2/Year and 8.203 kBTU/Thousand Gallons/Year, respectively. The analysis is also extended to understand the most promising EEMs for water treatment plants. An artificial neural network (ANN) is then developed to facilitate energy forecasting of water treatment plants using basic inputs including plant area and annual production. The outputs include estimated annual energy consumption and estimated potential savings that can be identified through conducting an energy audit. The training, testing and validation was satisfactory, but expected to much improve in the future with the addition of more assessment data to the IAC database. The ANN model will be the core of a basic energy analysis tool that can help the municipalities to easily evaluate the performance of their water treatment plants and estimate the potential savings that may be achieved as the result of performing an energy audit.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"102 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75884951","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}
Measurement of time resolved velocities with large accelerations is challenging because the optimal capture rate and pixel resolution changes with velocity. It is known for velocity measurements that high temporal resolution and low pixel resolution increases the velocity uncertainty. This makes selecting acceptable camera settings unintuitive and can result in highly uncertain measurements. For experimental conditions with slow velocities (< 10 m/s) where high temporal resolution is required (because of rapid acceleration) there arises a need for exponentially increasing pixel resolution to minimize experimental uncertainty which is often impossible to achieve experimentally. Desired measurements for early flame propagation have velocities which span a wide range of velocity which can be greater than 10 m/s during ignition and can drop to under 1 m/s depending on the pressure. This rapid velocity change all usually occurs within a millisecond timeframe. Typical camera-based velocity measurement usually observes either fast- or slow-moving objects with either an average velocity or a velocity at a single time. The goal of this work is to accurately measure such a rapidly changing experimental condition using camera-based measurement and understand the affect various processing methods have on the result. A practical method is presented here to quantify the noise and observe any induced errors from improper processing where measurable physical analogs are used to represent future experimental conditions. These experimental analogs are in the form of rotating disks which have known radial and velocity profiles that will enable the assessment of experimental parameters and postprocessing techniques. Parameters considered include pixel resolution, framerate, and smoothing techniques such as moving average, Whittaker, and Savitzky-Golay filters.
{"title":"Techniques for High-Speed Measurement of Accelerating Flame","authors":"James B Shaffer, Omid Askari","doi":"10.1115/imece2022-95252","DOIUrl":"https://doi.org/10.1115/imece2022-95252","url":null,"abstract":"\u0000 Measurement of time resolved velocities with large accelerations is challenging because the optimal capture rate and pixel resolution changes with velocity. It is known for velocity measurements that high temporal resolution and low pixel resolution increases the velocity uncertainty. This makes selecting acceptable camera settings unintuitive and can result in highly uncertain measurements. For experimental conditions with slow velocities (< 10 m/s) where high temporal resolution is required (because of rapid acceleration) there arises a need for exponentially increasing pixel resolution to minimize experimental uncertainty which is often impossible to achieve experimentally. Desired measurements for early flame propagation have velocities which span a wide range of velocity which can be greater than 10 m/s during ignition and can drop to under 1 m/s depending on the pressure. This rapid velocity change all usually occurs within a millisecond timeframe.\u0000 Typical camera-based velocity measurement usually observes either fast- or slow-moving objects with either an average velocity or a velocity at a single time. The goal of this work is to accurately measure such a rapidly changing experimental condition using camera-based measurement and understand the affect various processing methods have on the result. A practical method is presented here to quantify the noise and observe any induced errors from improper processing where measurable physical analogs are used to represent future experimental conditions. These experimental analogs are in the form of rotating disks which have known radial and velocity profiles that will enable the assessment of experimental parameters and postprocessing techniques. Parameters considered include pixel resolution, framerate, and smoothing techniques such as moving average, Whittaker, and Savitzky-Golay filters.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80601464","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}
Madison Faust, Zachary Ortman, Austin Chambers, M. Fitzpatrick, Jamir Gibson, Forde Norris, M. Williams, A. D. Johantges, Jae Kim, B. Riser, Brad C. McCoy, F. T. Davidson
In recent years, the United States Army has increasingly pushed to reduce carbon dioxide emissions across all installations and operations. This push is part of a broader effort to increase the sustainability and resilience of critical defense assets, by allowing them to operate for longer periods of time, with lower environmental impacts, lower costs, and increased mission readiness. One proposed solution to help reduce the emissions of Army installations is to replace conventional internal combustion engine vehicles with fully electrified vehicles. In particular, the non-tactical vehicle fleet is of primary interest to be rapidly converted to electrified drivetrains. The primary purpose of this work is to assess whether fully electrified vehicles have the lowest life-cycle emissions when considering the specific mission requirements and infrastructure present at Army installations. This work uses lifecycle analysis methods to compare the carbon emissions for vehicles with different drivetrains, located in different electric grid regions across the United States, while driving different distances to achieve the necessary missions of their operators. These variations in how the vehicles are designed, charged, and used showcases that, while electric vehicles are the best for many scenarios, they are not always the correct choice to maximize the total reduction in carbon emissions associated with transportation services at Army installations.
{"title":"Lifecycle Analysis to Improve the Sustainability of the United States Army’s Non-Tactical Vehicle Fleet","authors":"Madison Faust, Zachary Ortman, Austin Chambers, M. Fitzpatrick, Jamir Gibson, Forde Norris, M. Williams, A. D. Johantges, Jae Kim, B. Riser, Brad C. McCoy, F. T. Davidson","doi":"10.1115/imece2022-96142","DOIUrl":"https://doi.org/10.1115/imece2022-96142","url":null,"abstract":"\u0000 In recent years, the United States Army has increasingly pushed to reduce carbon dioxide emissions across all installations and operations. This push is part of a broader effort to increase the sustainability and resilience of critical defense assets, by allowing them to operate for longer periods of time, with lower environmental impacts, lower costs, and increased mission readiness. One proposed solution to help reduce the emissions of Army installations is to replace conventional internal combustion engine vehicles with fully electrified vehicles. In particular, the non-tactical vehicle fleet is of primary interest to be rapidly converted to electrified drivetrains. The primary purpose of this work is to assess whether fully electrified vehicles have the lowest life-cycle emissions when considering the specific mission requirements and infrastructure present at Army installations. This work uses lifecycle analysis methods to compare the carbon emissions for vehicles with different drivetrains, located in different electric grid regions across the United States, while driving different distances to achieve the necessary missions of their operators. These variations in how the vehicles are designed, charged, and used showcases that, while electric vehicles are the best for many scenarios, they are not always the correct choice to maximize the total reduction in carbon emissions associated with transportation services at Army installations.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78602328","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. Nokhosteen, Onur Ozkaya, Sarvenaz Sobhansarbandi
Aiming to meet the challenges of worldwide energy demand, solar energy is one of the fastest growing renewable energy sectors which can be used for providing heat to the end user on both residential and industrial scales. Amongst the various thermal systems used for providing solar heat, evacuated tube collectors are the most promising and play a crucial role in solar water heating (SWH) systems, therefore, increasing their efficiency and thermal output is extremely beneficial, especially in cold climates. In this study, an optimized parabolic reflector trough is designed in-house to eliminate the dependence of the system to sun’s availability and reduce the solar scattering. This solution will not only concentrate on increasing efficiency, but also modularity is a design targets to aid in increasing the market penetration of solar water heating systems. The system is tested in Midwest region of the United States and results are compared with regular solar water heater. The results show that maximum and minimum fin temperature enhancement of 19°C and 10°C were achieved, respectfully, with employing the solar reflector. Furthermore, as a result of the achieved enhancement, the proposed SWH system is more primed to be coupled with latent heat storage materials with higher melting temperature and latent heat of phase change.
{"title":"Performance Evaluation of a Solar Thermal Collector With Custom-Made Reflector: An Experimental Study in Midwest Region","authors":"A. Nokhosteen, Onur Ozkaya, Sarvenaz Sobhansarbandi","doi":"10.1115/imece2022-96304","DOIUrl":"https://doi.org/10.1115/imece2022-96304","url":null,"abstract":"\u0000 Aiming to meet the challenges of worldwide energy demand, solar energy is one of the fastest growing renewable energy sectors which can be used for providing heat to the end user on both residential and industrial scales. Amongst the various thermal systems used for providing solar heat, evacuated tube collectors are the most promising and play a crucial role in solar water heating (SWH) systems, therefore, increasing their efficiency and thermal output is extremely beneficial, especially in cold climates. In this study, an optimized parabolic reflector trough is designed in-house to eliminate the dependence of the system to sun’s availability and reduce the solar scattering. This solution will not only concentrate on increasing efficiency, but also modularity is a design targets to aid in increasing the market penetration of solar water heating systems. The system is tested in Midwest region of the United States and results are compared with regular solar water heater. The results show that maximum and minimum fin temperature enhancement of 19°C and 10°C were achieved, respectfully, with employing the solar reflector. Furthermore, as a result of the achieved enhancement, the proposed SWH system is more primed to be coupled with latent heat storage materials with higher melting temperature and latent heat of phase change.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81134300","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}
R. Sok, Jin Kusaka, H. Nakashima, Hidetaka Minagata
Thermoelectric generator (TEG) effectiveness in boosting hybridized, compressed natural gas (CNG) 3.0 L engines is demonstrated using a model-based development approach. Measured data from the corrugated fin-type TEG under different gas temperatures and mass flow rates are used for validating the model. The accurate TEG model can reproduce measured pressure loss, heat transfer, and thermal performance characteristics. Next, the model is integrated into the spark ignited CNG engine. Predicted engine performances are well-calibrated with measured data from the twin-turbocharged, mass-production engine used in light-duty delivery trucks. The engine model is validated with measured data for 35 conditions under the JE05 cycle (800–2800 RPM, 2.6–102 kW). The results show that the engine brake thermal efficiency (BTE) is improved by 0.56% using a 7 × 9 TEG module arrangement. A 9 × 10 arrangement can enhance the BTE to 0.8%. Effective electrical power is generated up to 1.168 kW from the TEG, depending on JE05 operating regions, without significant power loss.
{"title":"Thermoelectric Generation From Exhaust Heat in Electrified Natural Gas Trucks - Part1: Modeling and Analysis on Engine System Efficiency Improvement","authors":"R. Sok, Jin Kusaka, H. Nakashima, Hidetaka Minagata","doi":"10.1115/imece2022-96245","DOIUrl":"https://doi.org/10.1115/imece2022-96245","url":null,"abstract":"\u0000 Thermoelectric generator (TEG) effectiveness in boosting hybridized, compressed natural gas (CNG) 3.0 L engines is demonstrated using a model-based development approach. Measured data from the corrugated fin-type TEG under different gas temperatures and mass flow rates are used for validating the model. The accurate TEG model can reproduce measured pressure loss, heat transfer, and thermal performance characteristics. Next, the model is integrated into the spark ignited CNG engine. Predicted engine performances are well-calibrated with measured data from the twin-turbocharged, mass-production engine used in light-duty delivery trucks. The engine model is validated with measured data for 35 conditions under the JE05 cycle (800–2800 RPM, 2.6–102 kW). The results show that the engine brake thermal efficiency (BTE) is improved by 0.56% using a 7 × 9 TEG module arrangement. A 9 × 10 arrangement can enhance the BTE to 0.8%. Effective electrical power is generated up to 1.168 kW from the TEG, depending on JE05 operating regions, without significant power loss.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90522515","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}
Any inhabited base on the moon would require significant resources and power. Due to the high cost of delivering materials to the lunar surface, care must be taken to optimize energy storage and delivery systems. An exergy-based analysis of power generation systems based on a photovoltaic (PV) array coupled with energy storage is conducted. Exergy destruction rates are calculated through quasi-steady state energy and exergy balances, while exergy efficiencies for systems and subsystems are also quantified. The power system configurations analyzed include a PV array coupled with lithium-ion battery (LIB) energy storage and a PV array coupled with regenerative fuel cell (RFC) energy storage. Influence of parameters such as lunar latitude, size, and transient power demand are discussed. In both cases considered, the PV array dominates exergy performance of the overall system. Compared to the RFC, the LIB exhibits a slightly higher system exergy efficiency. Higher system efficiencies are observed during nighttime operation due to efficient discharge of energy storage. Daytime system efficiencies are reduced significantly by radiative heat loss from the solar array. Both configurations experience slightly better exergy efficiencies at lower lunar latitudes, closer to the equator.
{"title":"Exergy Analysis of Photovoltaics Coupled With Electrochemical Energy Storage for Lunar Power Applications","authors":"Phillip Dyer, Griffin Smith, G. Nelson","doi":"10.1115/imece2022-96993","DOIUrl":"https://doi.org/10.1115/imece2022-96993","url":null,"abstract":"\u0000 Any inhabited base on the moon would require significant resources and power. Due to the high cost of delivering materials to the lunar surface, care must be taken to optimize energy storage and delivery systems. An exergy-based analysis of power generation systems based on a photovoltaic (PV) array coupled with energy storage is conducted. Exergy destruction rates are calculated through quasi-steady state energy and exergy balances, while exergy efficiencies for systems and subsystems are also quantified.\u0000 The power system configurations analyzed include a PV array coupled with lithium-ion battery (LIB) energy storage and a PV array coupled with regenerative fuel cell (RFC) energy storage. Influence of parameters such as lunar latitude, size, and transient power demand are discussed. In both cases considered, the PV array dominates exergy performance of the overall system. Compared to the RFC, the LIB exhibits a slightly higher system exergy efficiency. Higher system efficiencies are observed during nighttime operation due to efficient discharge of energy storage. Daytime system efficiencies are reduced significantly by radiative heat loss from the solar array. Both configurations experience slightly better exergy efficiencies at lower lunar latitudes, closer to the equator.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88755328","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}
This study involves numerical analyses of a 7.5 m parabolic dish concentrator for membrane distillation desalination applications. Optical and heat transfer performance of conical receivers with an angle of 45°, 75°, and a spiral receiver was investigated. Receiver designs considered here have helical coil receivers that carry heat transfer fluid (HTF). The optical performance of these three conical receivers was studied based on the distance of receivers from the focal point. This study considered three distances: 0.06m, 0.12m, and 0.18m. Ray tracing simulation has been carried out to obtain the receiver’s radiation heat flux distribution data. It is observed that the 45° conical receiver yields the highest optical efficiency, 82%, when the receiver is placed 0.12m from the focal point. Heat flux data obtained during the optical simulations have been utilized as a boundary condition. In addition, numerical simulations are carried out to evaluate the heat transfer performance of the 45° conical receiver. The study included Reynolds numbers of 1,917, 10,222, and 19,167. The outlet temperatures have been examined.
{"title":"Optical and Heat Transfer Performance of Conical Receivers for Desalination Application","authors":"Abhinay Soanker, A. Oztekin","doi":"10.1115/imece2022-94804","DOIUrl":"https://doi.org/10.1115/imece2022-94804","url":null,"abstract":"\u0000 This study involves numerical analyses of a 7.5 m parabolic dish concentrator for membrane distillation desalination applications. Optical and heat transfer performance of conical receivers with an angle of 45°, 75°, and a spiral receiver was investigated. Receiver designs considered here have helical coil receivers that carry heat transfer fluid (HTF). The optical performance of these three conical receivers was studied based on the distance of receivers from the focal point. This study considered three distances: 0.06m, 0.12m, and 0.18m. Ray tracing simulation has been carried out to obtain the receiver’s radiation heat flux distribution data. It is observed that the 45° conical receiver yields the highest optical efficiency, 82%, when the receiver is placed 0.12m from the focal point.\u0000 Heat flux data obtained during the optical simulations have been utilized as a boundary condition. In addition, numerical simulations are carried out to evaluate the heat transfer performance of the 45° conical receiver. The study included Reynolds numbers of 1,917, 10,222, and 19,167. The outlet temperatures have been examined.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89558208","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}
Katherine Mitchell, H. Horner, A. Resnick, Jungkyu Park, E. Farfán, T. Yee, A. Hummel
Molecular displacement occurs in the oxide fuels of nuclear reactors during operation. This causes several types of point defects to be generated inside the oxide nuclear fuels. To improve the safety and efficiency of nuclear reactor operation, it is necessary to better understand the effects of point defects on the properties of the oxide fuels. In this study, we examine the effects of interstitial defects on thermal transport in two representative actinide oxides used in modern reactors (UO2, and PuO2). Reverse non-equilibrium molecular dynamics (RNEMD) is employed to approximate the thermal conductivities for the aforementioned fuels at several sample lengths and at defect concentrations of 0.1%, 1%, and 5%. The results show that alterations to the lattice structures of these fuels reduce their thermal conductivities significantly. For example, oxygen interstitial defects at concentrations even as low as 0.1% decreased thermal conductivity by 20% at 100 units for each fuel.
{"title":"Thermal Transport in Actinide Oxide Fuels With Interstitial Defects","authors":"Katherine Mitchell, H. Horner, A. Resnick, Jungkyu Park, E. Farfán, T. Yee, A. Hummel","doi":"10.1115/IMECE2019-11027","DOIUrl":"https://doi.org/10.1115/IMECE2019-11027","url":null,"abstract":"\u0000 Molecular displacement occurs in the oxide fuels of nuclear reactors during operation. This causes several types of point defects to be generated inside the oxide nuclear fuels. To improve the safety and efficiency of nuclear reactor operation, it is necessary to better understand the effects of point defects on the properties of the oxide fuels. In this study, we examine the effects of interstitial defects on thermal transport in two representative actinide oxides used in modern reactors (UO2, and PuO2). Reverse non-equilibrium molecular dynamics (RNEMD) is employed to approximate the thermal conductivities for the aforementioned fuels at several sample lengths and at defect concentrations of 0.1%, 1%, and 5%. The results show that alterations to the lattice structures of these fuels reduce their thermal conductivities significantly. For example, oxygen interstitial defects at concentrations even as low as 0.1% decreased thermal conductivity by 20% at 100 units for each fuel.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75220550","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}
Presented here is a novel system that uses an aluminum-based fuel to continuously produce electrical power at the kW scale via a hydrogen fuel cell. This fuel has an energy density of 23.3 kWh/L and can be produced from abundant scrap aluminum via a minimal surface treatment of gallium and indium. These additional metals, which in total comprise 2.5% of the fuel’s mass, permeate the grain boundary network of the aluminum and disrupt its oxide layer, thereby enabling the fuel to react exothermically with water to produce hydrogen gas and aluminum oxyhydroxide, an inert and valuable byproduct. To generate electrical power using this fuel, the aluminum-water reaction is controlled via water input to a reaction vessel in order to produce a constant flow of hydrogen, which is then consumed in a fuel cell to produce electricity. As validation of this power system architecture, we present the design and implementation of two example systems that successfully demonstrate this approach. The first is a 3 kW emergency power supply and the second is a 10 kW power system integrated into a BWM i3 electric vehicle.
{"title":"High-Power Fuel Cell Systems Fueled by Recycled Aluminum","authors":"Peter Godart, Jason Fischman, D. Hart","doi":"10.1115/imece2019-10478","DOIUrl":"https://doi.org/10.1115/imece2019-10478","url":null,"abstract":"\u0000 Presented here is a novel system that uses an aluminum-based fuel to continuously produce electrical power at the kW scale via a hydrogen fuel cell. This fuel has an energy density of 23.3 kWh/L and can be produced from abundant scrap aluminum via a minimal surface treatment of gallium and indium. These additional metals, which in total comprise 2.5% of the fuel’s mass, permeate the grain boundary network of the aluminum and disrupt its oxide layer, thereby enabling the fuel to react exothermically with water to produce hydrogen gas and aluminum oxyhydroxide, an inert and valuable byproduct. To generate electrical power using this fuel, the aluminum-water reaction is controlled via water input to a reaction vessel in order to produce a constant flow of hydrogen, which is then consumed in a fuel cell to produce electricity. As validation of this power system architecture, we present the design and implementation of two example systems that successfully demonstrate this approach. The first is a 3 kW emergency power supply and the second is a 10 kW power system integrated into a BWM i3 electric vehicle.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77481377","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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