The thermal performance of a candidate next-generation falling particle receiver (FPR) is analyzed subject to various expected operating conditions. This receiver design was created from the result of an extensive optimization study and developed to support the Generation 3 Particle Pilot Plant (G3P3) project. Previous analysis demonstrated high thermal efficiencies for the receiver at nominal quiescent conditions, but further analysis was required to demonstrate that the receiver could maintain that thermal performance in a wide range of anticipated environments. In this study, the thermal efficiency was numerically evaluated using a CFD model for different wind conditions and shown to maintain a thermal efficiency above 83% for considered wind conditions. Moreover, the effect of radiative spillage from the incoming concentrated solar beam on the receiver exterior was investigated using ray tracing and CFD models. The exterior wall material temperature limits were not exceeded for the anticipated design power from the heliostats. Additional features were numerically explored including the addition of a chimney to capture particle fines and waste heat and a multi-stage concept to maximize curtain opacity. Particle fines of 10 μm were shown to preferentially flow into this chimney rather than out of the aperture, and the multi-stage design decreased radiative losses and minimized wall temperatures behind the particle curtain.
{"title":"Improving Next-Generation Falling Particle Receiver Designs Subject to Anticipated Operating Conditions","authors":"Brantley Mills, Reid Shaeffer, L. Yue, C. Ho","doi":"10.1115/es2020-1667","DOIUrl":"https://doi.org/10.1115/es2020-1667","url":null,"abstract":"\u0000 The thermal performance of a candidate next-generation falling particle receiver (FPR) is analyzed subject to various expected operating conditions. This receiver design was created from the result of an extensive optimization study and developed to support the Generation 3 Particle Pilot Plant (G3P3) project. Previous analysis demonstrated high thermal efficiencies for the receiver at nominal quiescent conditions, but further analysis was required to demonstrate that the receiver could maintain that thermal performance in a wide range of anticipated environments. In this study, the thermal efficiency was numerically evaluated using a CFD model for different wind conditions and shown to maintain a thermal efficiency above 83% for considered wind conditions. Moreover, the effect of radiative spillage from the incoming concentrated solar beam on the receiver exterior was investigated using ray tracing and CFD models. The exterior wall material temperature limits were not exceeded for the anticipated design power from the heliostats. Additional features were numerically explored including the addition of a chimney to capture particle fines and waste heat and a multi-stage concept to maximize curtain opacity. Particle fines of 10 μm were shown to preferentially flow into this chimney rather than out of the aperture, and the multi-stage design decreased radiative losses and minimized wall temperatures behind the particle curtain.","PeriodicalId":8602,"journal":{"name":"ASME 2020 14th International Conference on Energy Sustainability","volume":"131 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80263610","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 rapid growth of renewable energy increases the importance of economically firming the electricity supply from variable solar photovoltaic- and wind-power generators. Energy storage will be the key to manage variability and to bridge the generation gap over time scales of hours or days for high renewable grid integration. The integration of renewable power and storage of excess electricity has several significant and positive impacts including: 1) expanding the renewable energy portion of total electricity generation, 2) improving the peak-load response, and 3) coordinating the electricity supply and demand over the grid. Long-duration energy storage can potentially complement the reduction of fossil-fuel baseload generation that otherwise would risk grid security when a large portion of grid power comes from variable renewable sources. Several energy storage methods are deployed or under development, including mechanical, chemical or electrochemical, and thermal energy storage (TES). Comparing their economic potential for different scales and applications helps identify suitable technology to support high renewable grid integration. Despite the progress of TES technologies developed and deployed with concentrating solar power (CSP) systems, TES has been undervalued for its potential role in electric energy storage. This paper introduces TES methods applicable to grid energy storage and particularly focuses on solid-particle-based TES to serve the purpose of long-duration energy storage (LDES). The objective of this paper is to present a standalone particle-based TES system for electric storage and to show the potential of TES systems for LDES applications over other energy storage methods such as batteries, compressed-air energy storage, or pumped-storage hydropower.
{"title":"Thermal Energy Storage Using Solid Particles for Long-Duration Energy Storage","authors":"Zhiwen Ma, P. Davenport, J. Martinek","doi":"10.1115/es2020-1693","DOIUrl":"https://doi.org/10.1115/es2020-1693","url":null,"abstract":"\u0000 The rapid growth of renewable energy increases the importance of economically firming the electricity supply from variable solar photovoltaic- and wind-power generators. Energy storage will be the key to manage variability and to bridge the generation gap over time scales of hours or days for high renewable grid integration. The integration of renewable power and storage of excess electricity has several significant and positive impacts including: 1) expanding the renewable energy portion of total electricity generation, 2) improving the peak-load response, and 3) coordinating the electricity supply and demand over the grid. Long-duration energy storage can potentially complement the reduction of fossil-fuel baseload generation that otherwise would risk grid security when a large portion of grid power comes from variable renewable sources. Several energy storage methods are deployed or under development, including mechanical, chemical or electrochemical, and thermal energy storage (TES). Comparing their economic potential for different scales and applications helps identify suitable technology to support high renewable grid integration. Despite the progress of TES technologies developed and deployed with concentrating solar power (CSP) systems, TES has been undervalued for its potential role in electric energy storage. This paper introduces TES methods applicable to grid energy storage and particularly focuses on solid-particle-based TES to serve the purpose of long-duration energy storage (LDES). The objective of this paper is to present a standalone particle-based TES system for electric storage and to show the potential of TES systems for LDES applications over other energy storage methods such as batteries, compressed-air energy storage, or pumped-storage hydropower.","PeriodicalId":8602,"journal":{"name":"ASME 2020 14th International Conference on Energy Sustainability","volume":"152 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86668205","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 paper investigates the economic benefit of incorporating solar-based preheating of Manganese ore before smelting in electric submerged arc furnaces. Manganese ore is smelted to produce Manganese ferroalloy, a key component in steel production. The smelting process is highly energy intensive, with temperatures up to 1600 °C. The paper discusses the developed methodology for determining the configuration of a concentrating solar thermal (CST) plant to produce high temperature process heat. The CST plant is sized to preheat the ore to 600 °C before it enters the smelter — currently ore enters at ambient temperature. The preheating leads to economic and environmental benefits by offering lower cost heat and reducing carbon emissions for the process.
{"title":"Concentrating Solar Thermal Process Heat for Manganese Ferroalloy Production: Plant Modelling and Thermal Energy Storage Dispatch Optimization","authors":"T. Mckechnie, C. McGregor, G. Venter","doi":"10.1115/es2020-1635","DOIUrl":"https://doi.org/10.1115/es2020-1635","url":null,"abstract":"\u0000 This paper investigates the economic benefit of incorporating solar-based preheating of Manganese ore before smelting in electric submerged arc furnaces. Manganese ore is smelted to produce Manganese ferroalloy, a key component in steel production. The smelting process is highly energy intensive, with temperatures up to 1600 °C. The paper discusses the developed methodology for determining the configuration of a concentrating solar thermal (CST) plant to produce high temperature process heat. The CST plant is sized to preheat the ore to 600 °C before it enters the smelter — currently ore enters at ambient temperature. The preheating leads to economic and environmental benefits by offering lower cost heat and reducing carbon emissions for the process.","PeriodicalId":8602,"journal":{"name":"ASME 2020 14th International Conference on Energy Sustainability","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83734770","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}
Daniel Celvi, Christa Schreiber, R. Tirawat, G. Zhu
Beginning in 2018, the National Renewable Energy Laboratory restarted exposure campaigns on new and archived samples as part of a multiyear project, some with outdoor exposure for more than a decade. By resuming exposure and collecting and analyzing data on thousands of samples going back decades, several goals can be advanced that can be difficult to determine within the timeline of most projects: 1) correlating an accelerated exposure campaign to outdoor aging, specifically with xenon arc lamp exposure chambers; 2) drawing conclusions between specific corrosion mechanisms and weather patterns; and 3) finding novel relationships between mirror composition and performance. In addition to building and mining a database, we will experiment with new characterization techniques, primarily focused on macroscopic and microscopic imaging. In introducing these techniques more broadly, it may be possible to reveal a more direct line between optical performance and exposure campaigns by better understanding the degradation mechanisms occurring.
{"title":"Update on NREL Outdoor Exposure Campaign of Solar Mirrors","authors":"Daniel Celvi, Christa Schreiber, R. Tirawat, G. Zhu","doi":"10.1115/es2020-1647","DOIUrl":"https://doi.org/10.1115/es2020-1647","url":null,"abstract":"\u0000 Beginning in 2018, the National Renewable Energy Laboratory restarted exposure campaigns on new and archived samples as part of a multiyear project, some with outdoor exposure for more than a decade. By resuming exposure and collecting and analyzing data on thousands of samples going back decades, several goals can be advanced that can be difficult to determine within the timeline of most projects: 1) correlating an accelerated exposure campaign to outdoor aging, specifically with xenon arc lamp exposure chambers; 2) drawing conclusions between specific corrosion mechanisms and weather patterns; and 3) finding novel relationships between mirror composition and performance.\u0000 In addition to building and mining a database, we will experiment with new characterization techniques, primarily focused on macroscopic and microscopic imaging. In introducing these techniques more broadly, it may be possible to reveal a more direct line between optical performance and exposure campaigns by better understanding the degradation mechanisms occurring.","PeriodicalId":8602,"journal":{"name":"ASME 2020 14th International Conference on Energy Sustainability","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75239883","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}
Kenneth Armijo, M. Carlson, D. Dorsey, J. Christian, C. Turchi
Nitrate molten salt concentrating solar power (CSP) systems are currently deployed globally and are considered state-of the art heat transfer fluids (HTFs) for present day high-temperature operation. Although slightly higher limits may be possible with molten salt, to fully realize SunShot efficiency goals of $15/kWhth HTFs and an LCOE of 6¢/kWh, HTF technologies working at higher temperatures (e.g., 650 °C to 750 °C) will require an alternative to molten salts, such as with alkali metal systems. This investigation explores the development of a 2.0 MWth sodium receiver system that employs a sodium receiver as the HTF, as well as with a ternary chloride (20%NaCl/40%MgCl/40%KCl by mol wt.%) salt as a thermal energy storage (TES) medium to facilitate a 6-hr. storage duration. A sodium-to-salt heat exchanger model as well as a salt-to-sCO2 primary heat exchanger model are employed and evaluated in this investigation. A thermodynamic system design model was developed using Engineering Equation Solver (EES) where state properties were calculated at inlets and outlets along both hot and cold legs of the pilot-scale plant. This investigation assesses receiver performance as well as system efficiency studies for the pump and system operational ranges. Results found that high efficiency sodium receivers were found to have higher heat transfer coefficients and required far less spreading of incident flux. The system performance model results suggest that for a pump speed of 2400 RPM, respective hot and cold pump TDH values were determined to be 260.1–307 ft. and 260.1–307 ft for pump flow rates of 90–120 GPM.
{"title":"System Design of a 2.0 MWth Sodium/Molten Salt Pilot System","authors":"Kenneth Armijo, M. Carlson, D. Dorsey, J. Christian, C. Turchi","doi":"10.1115/es2020-1622","DOIUrl":"https://doi.org/10.1115/es2020-1622","url":null,"abstract":"\u0000 Nitrate molten salt concentrating solar power (CSP) systems are currently deployed globally and are considered state-of the art heat transfer fluids (HTFs) for present day high-temperature operation. Although slightly higher limits may be possible with molten salt, to fully realize SunShot efficiency goals of $15/kWhth HTFs and an LCOE of 6¢/kWh, HTF technologies working at higher temperatures (e.g., 650 °C to 750 °C) will require an alternative to molten salts, such as with alkali metal systems. This investigation explores the development of a 2.0 MWth sodium receiver system that employs a sodium receiver as the HTF, as well as with a ternary chloride (20%NaCl/40%MgCl/40%KCl by mol wt.%) salt as a thermal energy storage (TES) medium to facilitate a 6-hr. storage duration. A sodium-to-salt heat exchanger model as well as a salt-to-sCO2 primary heat exchanger model are employed and evaluated in this investigation. A thermodynamic system design model was developed using Engineering Equation Solver (EES) where state properties were calculated at inlets and outlets along both hot and cold legs of the pilot-scale plant. This investigation assesses receiver performance as well as system efficiency studies for the pump and system operational ranges. Results found that high efficiency sodium receivers were found to have higher heat transfer coefficients and required far less spreading of incident flux. The system performance model results suggest that for a pump speed of 2400 RPM, respective hot and cold pump TDH values were determined to be 260.1–307 ft. and 260.1–307 ft for pump flow rates of 90–120 GPM.","PeriodicalId":8602,"journal":{"name":"ASME 2020 14th International Conference on Energy Sustainability","volume":"65 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85047085","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 numerical model of the CentRec® receiver has been developed and validated using the measurement data collected during the experimental test campaign of the centrifugal particle system at the solar tower Jülich. The model has been used to calculate the thermo-optical efficiency of a scaled-up 20 MWth receiver for various receiver geometries. A cost function has been deduced and was used to perform a technoeconomic optimization on an LCOH (levelized cost of heat) basis of the CentRec® receiver concept. Attractive LCOH as low as 0.0209 €/kWhth for a system with thermal storage, or as low as 0.0150 €/kWhth for the LCOH without storage, are predicted. This study has shown that the optimal configuration from an LCOH perspective for a 20 MWth centrifugal particle receiver reaches specific receiver costs of 35 €/kWth. Hereby the costs of the receiver can be reduced by 60 % compared to the original configuration.
{"title":"Design and Cost Study of Improved Scaled-Up Centrifugal Particle Receiver Based on Simulation","authors":"C. Frantz, R. Buck, L. Amsbeck","doi":"10.1115/es2020-1626","DOIUrl":"https://doi.org/10.1115/es2020-1626","url":null,"abstract":"\u0000 A numerical model of the CentRec® receiver has been developed and validated using the measurement data collected during the experimental test campaign of the centrifugal particle system at the solar tower Jülich. The model has been used to calculate the thermo-optical efficiency of a scaled-up 20 MWth receiver for various receiver geometries. A cost function has been deduced and was used to perform a technoeconomic optimization on an LCOH (levelized cost of heat) basis of the CentRec® receiver concept. Attractive LCOH as low as 0.0209 €/kWhth for a system with thermal storage, or as low as 0.0150 €/kWhth for the LCOH without storage, are predicted. This study has shown that the optimal configuration from an LCOH perspective for a 20 MWth centrifugal particle receiver reaches specific receiver costs of 35 €/kWth. Hereby the costs of the receiver can be reduced by 60 % compared to the original configuration.","PeriodicalId":8602,"journal":{"name":"ASME 2020 14th International Conference on Energy Sustainability","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84912574","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}
Deliquescent salts have high water vapor adsorption capacity, but they dissolve in water by forming crystalline hydrates. That restricts their use in different water vapor adsorption applications. However, this limitation can be overcome by incorporating deliquescent salts within a polymer matrix which will keep the salt solution in place. Furthermore, if the polymer matrix used is also capable of adsorbing water vapor, it will further improve the overall performance of desiccant system. Therefore, in this work, we are proposing the synthesis and use of a highly effective new solid polymer desiccant material, i.e. superporous hydrogel (SPHs) of poly(sodium acrylate-co-acrylic acid (P(SA-co-AA)), and subsequently its composite with deliquescent salt, i.e. calcium chloride (CaCl2), to adsorb water vapors from humid air without the dissolution of the salt in the adsorbed water. Parental PAA-SPHs matrix alone exhibited an adsorption capacity of 1.02 gw/gads which increased to 3.35 gw/gads after incorporating CaCl2 salt in the polymer matrix. Both materials exhibited type-III adsorption isotherm and the experimental isotherm data fitted to the Guggenheim, Anderson and Boer (GAB) isotherm model. However, the adsorption kinetics followed linear driving force model which suggested that this extremely high adsorption capacity was due to the diffusion of water molecules into the interconnected pores of SPHs via capillary channels followed by the attachment of adsorbed water molecules to the CaCl2 salt present in the polymer matrix. Furthermore, the adsorbents were used successively for six cycles of adsorption with a very little loss in adsorption capacity. Therefore, the proposed polymer desiccant material overcomes the problem of dissolution of deliquescent salts and opens the doors for a new class of highly effective solid desiccant material.
潮解盐具有较高的水蒸气吸附能力，但溶于水时形成结晶水合物。这限制了它们在不同的水蒸气吸附应用中的使用。然而，这一限制可以通过在聚合物基质中加入潮解盐来克服，这将使盐溶液保持原位。此外，如果所使用的聚合物基质也能够吸附水蒸气，将进一步提高干燥剂系统的整体性能。因此，在这项工作中，我们建议合成和使用一种高效的新型固体聚合物干燥剂材料，即聚(丙烯酸钠-共丙烯酸(P(SA-co-AA))的超孔水凝胶(SPHs)，并随后将其与潮解盐，即氯化钙(CaCl2)复合，以吸附潮湿空气中的水蒸气而不会溶解在吸附水中。单独亲本PAA-SPHs基质的吸附容量为1.02 gw/gads，加入CaCl2盐后，吸附容量增加到3.35 gw/gads。两种材料均表现出iii型吸附等温线，实验等温线数据符合Guggenheim, Anderson and Boer (GAB)等温线模型。然而，吸附动力学遵循线性驱动力模型，这表明这种极高的吸附能力是由于水分子通过毛细管通道扩散到SPHs的互连孔中，然后吸附的水分子附着在聚合物基质中的CaCl2盐上。此外，在吸附容量损失很小的情况下，连续使用了6次吸附剂。因此，所提出的聚合物干燥剂材料克服了潮解盐的溶解问题，为一类新型高效固体干燥剂材料打开了大门。
{"title":"Adsorption Isotherm and Kinetics of Water Vapor Adsorption Using Novel Super-Porous Hydrogel Composites","authors":"H. Mittal, Ali Al-Alili, S. Alhassan","doi":"10.1115/es2020-1642","DOIUrl":"https://doi.org/10.1115/es2020-1642","url":null,"abstract":"\u0000 Deliquescent salts have high water vapor adsorption capacity, but they dissolve in water by forming crystalline hydrates. That restricts their use in different water vapor adsorption applications. However, this limitation can be overcome by incorporating deliquescent salts within a polymer matrix which will keep the salt solution in place. Furthermore, if the polymer matrix used is also capable of adsorbing water vapor, it will further improve the overall performance of desiccant system. Therefore, in this work, we are proposing the synthesis and use of a highly effective new solid polymer desiccant material, i.e. superporous hydrogel (SPHs) of poly(sodium acrylate-co-acrylic acid (P(SA-co-AA)), and subsequently its composite with deliquescent salt, i.e. calcium chloride (CaCl2), to adsorb water vapors from humid air without the dissolution of the salt in the adsorbed water. Parental PAA-SPHs matrix alone exhibited an adsorption capacity of 1.02 gw/gads which increased to 3.35 gw/gads after incorporating CaCl2 salt in the polymer matrix. Both materials exhibited type-III adsorption isotherm and the experimental isotherm data fitted to the Guggenheim, Anderson and Boer (GAB) isotherm model. However, the adsorption kinetics followed linear driving force model which suggested that this extremely high adsorption capacity was due to the diffusion of water molecules into the interconnected pores of SPHs via capillary channels followed by the attachment of adsorbed water molecules to the CaCl2 salt present in the polymer matrix. Furthermore, the adsorbents were used successively for six cycles of adsorption with a very little loss in adsorption capacity. Therefore, the proposed polymer desiccant material overcomes the problem of dissolution of deliquescent salts and opens the doors for a new class of highly effective solid desiccant material.","PeriodicalId":8602,"journal":{"name":"ASME 2020 14th International Conference on Energy Sustainability","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79146094","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}
Syed Muhammad Rizvi, Yousof Nayfeh, B. Far, Donghyun Shin
Concentrated Solar Power (CSP) is one of the most efficient mega-scale renewable Energy sources. However, the overall cost of energy production is not viable for commercial usage and supplanting with fossil fuels or energy produced by nuclear ways. Its operational cost mainly lies in the electrical and thermal systems of the plant. The thermal system comprises of heat storage and heat transfer system. Any enhancement to heat storage or transfer system will directly reduce the cost of operation and increase the yield. Conventionally, oils stable up to 400C were used to transfer and store heat, however more recently, molten salts have been operational in the field for purpose of heat transfer but still, their thermal storage and conduction are limited. The current work explores the possibility of boosting the thermal storage capacity of molten salts through the latent heat of added phase change materials and increasing the specific heat at the same time by adding silica encapsulated zinc nanoparticles. We studied the advantage of adding coated Zn nano-sized particles to carbonate eutectic mixture for enhanced thermal energy storage and heat capacity enhancement. Zinc particles (40nm–60nm) obtained from the commercial sources were coated with silica shells using the solgel process under alkaline conditions. The nano-capsules were then dispersed in a mixture of carbonate salts. A differential scanning calorimeter was employed to characterize the thermal properties of the mixture. Tranmission electron miocroscopy was employed to characterize nanoparticles and electron diffraction Spectroscopy was performed to characterize materials and strcutures involved.
{"title":"Use of Silica Coated Zinc Nanoparticles for Enhancement in Thermal Properties of Carbonate Eutectic Salt for Concentrated Solar Power Plants","authors":"Syed Muhammad Rizvi, Yousof Nayfeh, B. Far, Donghyun Shin","doi":"10.1115/es2020-1710","DOIUrl":"https://doi.org/10.1115/es2020-1710","url":null,"abstract":"\u0000 Concentrated Solar Power (CSP) is one of the most efficient mega-scale renewable Energy sources. However, the overall cost of energy production is not viable for commercial usage and supplanting with fossil fuels or energy produced by nuclear ways. Its operational cost mainly lies in the electrical and thermal systems of the plant. The thermal system comprises of heat storage and heat transfer system. Any enhancement to heat storage or transfer system will directly reduce the cost of operation and increase the yield. Conventionally, oils stable up to 400C were used to transfer and store heat, however more recently, molten salts have been operational in the field for purpose of heat transfer but still, their thermal storage and conduction are limited. The current work explores the possibility of boosting the thermal storage capacity of molten salts through the latent heat of added phase change materials and increasing the specific heat at the same time by adding silica encapsulated zinc nanoparticles. We studied the advantage of adding coated Zn nano-sized particles to carbonate eutectic mixture for enhanced thermal energy storage and heat capacity enhancement. Zinc particles (40nm–60nm) obtained from the commercial sources were coated with silica shells using the solgel process under alkaline conditions. The nano-capsules were then dispersed in a mixture of carbonate salts. A differential scanning calorimeter was employed to characterize the thermal properties of the mixture. Tranmission electron miocroscopy was employed to characterize nanoparticles and electron diffraction Spectroscopy was performed to characterize materials and strcutures involved.","PeriodicalId":8602,"journal":{"name":"ASME 2020 14th International Conference on Energy Sustainability","volume":"97 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73837201","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}
Globally there are several viable sources of renewable, low-temperature heat (below 130°C) particularly solar energy, geothermal energy, and energy generated from industrial wastes. Increased exploitation of these low-temperature options has the definite potential of reducing fossil fuel consumption with its attendant very harmful greenhouse gas emissions. Researchers have universally identified the organic Rankine cycle (ORC) as a practicable and promising system to generate electrical power from renewable sources based on its beneficial use of volatile organic fluids as working fluids (WFs). In recent times, researchers have also shown a preference for/an inclination towards deployment of zeotropic mixtures as ORC WFs because of their capacity to improve thermodynamic performance of ORC systems, a feat enabled by better matches of the temperature profiles of the WF and the heat source/sink. This paper demonstrates both the technical feasibility and the notable advantages of using zeotropic mixtures as WFs through a simulation study of an ORC system. The study examines the thermodynamic performance of ORC systems using zeotropic WF mixtures to generate electricity driven by low-temperature solar heat source for building applications. A thermodynamic model is developed with an ORC system both with and excluding a regenerator. Five zeotropic mixtures with varying compositions of R245fa/propane, R245fa/hexane, R245fa/heptane, pentane/hexane and isopentane/hexane are evaluated and compared to identify the best combinations of WF mixtures that can yield high efficiency in their system cycles. The study also investigates the effects of the volumetric flow ratio, and evaporation and condensation temperature glides on the ORC’s thermodynamic performance. Following a detailed analysis of each mixture, R245fa/propane is selected for parametric study to examine the effects of operating parameters on the system’s efficiency and sustainability index. For zeotropic mixtures, results showed that there is an optimal composition range within which binary mixtures are inclined to perform more efficiently than the component pure fluids. In addition, a significant increase in cycle efficiency can be achieved with a regenerative ORC, with cycle efficiency ranging between 3.1–9.8% and 8.6–17.4% for ORC both without and with regeneration, respectively. Results also showed that exploiting zeotropic mixtures could enlarge the limitation experienced in selecting WFs for low-temperature solar organic Rankine cycles.
{"title":"Performance Investigation of Solar Organic Rankine Cycle Systems With and Without Regeneration and With Zeotropic Working Fluid Mixtures for Use in Micro-Cogeneration","authors":"W. Yaïci, E. Entchev, P. Sardari","doi":"10.1115/es2020-1616","DOIUrl":"https://doi.org/10.1115/es2020-1616","url":null,"abstract":"\u0000 Globally there are several viable sources of renewable, low-temperature heat (below 130°C) particularly solar energy, geothermal energy, and energy generated from industrial wastes. Increased exploitation of these low-temperature options has the definite potential of reducing fossil fuel consumption with its attendant very harmful greenhouse gas emissions. Researchers have universally identified the organic Rankine cycle (ORC) as a practicable and promising system to generate electrical power from renewable sources based on its beneficial use of volatile organic fluids as working fluids (WFs). In recent times, researchers have also shown a preference for/an inclination towards deployment of zeotropic mixtures as ORC WFs because of their capacity to improve thermodynamic performance of ORC systems, a feat enabled by better matches of the temperature profiles of the WF and the heat source/sink.\u0000 This paper demonstrates both the technical feasibility and the notable advantages of using zeotropic mixtures as WFs through a simulation study of an ORC system. The study examines the thermodynamic performance of ORC systems using zeotropic WF mixtures to generate electricity driven by low-temperature solar heat source for building applications. A thermodynamic model is developed with an ORC system both with and excluding a regenerator. Five zeotropic mixtures with varying compositions of R245fa/propane, R245fa/hexane, R245fa/heptane, pentane/hexane and isopentane/hexane are evaluated and compared to identify the best combinations of WF mixtures that can yield high efficiency in their system cycles.\u0000 The study also investigates the effects of the volumetric flow ratio, and evaporation and condensation temperature glides on the ORC’s thermodynamic performance. Following a detailed analysis of each mixture, R245fa/propane is selected for parametric study to examine the effects of operating parameters on the system’s efficiency and sustainability index.\u0000 For zeotropic mixtures, results showed that there is an optimal composition range within which binary mixtures are inclined to perform more efficiently than the component pure fluids. In addition, a significant increase in cycle efficiency can be achieved with a regenerative ORC, with cycle efficiency ranging between 3.1–9.8% and 8.6–17.4% for ORC both without and with regeneration, respectively. Results also showed that exploiting zeotropic mixtures could enlarge the limitation experienced in selecting WFs for low-temperature solar organic Rankine cycles.","PeriodicalId":8602,"journal":{"name":"ASME 2020 14th International Conference on Energy Sustainability","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88085699","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}
On the anode side of a direct methanol fuel cell, carbon dioxide bubbles are generated as a result of the methanol oxidation reaction. The accumulation of such bubbles prevents methanol from reaching the gas diffusion layer. Hence, a significant reduction in the reaction rate occurs, which limits the maximum current density of the cell. To keep carbon dioxide bubbles away from the gas diffusion layer interface, a new design of the anode flow channel besides wall surface treatment is developed. Such a design can introduce the Concus-Finn phenomena, which forces the carbon dioxide bubbles to move away from the gas diffusion layer due to capillary forces. This can be achieved by using a trapezoidal shape of the flow channel, as well as the combined effect of hydrophobic and hydrophilic surface treatments on the gas-diffusion layer and channel walls. To identify the optimal design of the anode flow channel, a three-dimensional, two-phase flow model is developed. The model is numerically simulated and results are validated with available measurements. Results indicated that treating the gas-diffusion layer with a hydrophilic layer increases the area in direct contact with liquid methanol. Besides, the hydrophobic top channel surfaces make it easier for the carbon dioxide bubbles to attach and spread out on the channel top surface. The current findings create a promising opportunity to improve the performance of direct methanol fuel cells.
{"title":"Effect of Anode Flow Channel Design on the Carbon Dioxide Bubble Removal in Direct Methanol Fuel Cells","authors":"Sameer Osman, S. Ookawara, Mahmoud A. Ahmed","doi":"10.1115/es2020-1659","DOIUrl":"https://doi.org/10.1115/es2020-1659","url":null,"abstract":"\u0000 On the anode side of a direct methanol fuel cell, carbon dioxide bubbles are generated as a result of the methanol oxidation reaction. The accumulation of such bubbles prevents methanol from reaching the gas diffusion layer. Hence, a significant reduction in the reaction rate occurs, which limits the maximum current density of the cell. To keep carbon dioxide bubbles away from the gas diffusion layer interface, a new design of the anode flow channel besides wall surface treatment is developed. Such a design can introduce the Concus-Finn phenomena, which forces the carbon dioxide bubbles to move away from the gas diffusion layer due to capillary forces. This can be achieved by using a trapezoidal shape of the flow channel, as well as the combined effect of hydrophobic and hydrophilic surface treatments on the gas-diffusion layer and channel walls. To identify the optimal design of the anode flow channel, a three-dimensional, two-phase flow model is developed. The model is numerically simulated and results are validated with available measurements. Results indicated that treating the gas-diffusion layer with a hydrophilic layer increases the area in direct contact with liquid methanol. Besides, the hydrophobic top channel surfaces make it easier for the carbon dioxide bubbles to attach and spread out on the channel top surface. The current findings create a promising opportunity to improve the performance of direct methanol fuel cells.","PeriodicalId":8602,"journal":{"name":"ASME 2020 14th International Conference on Energy Sustainability","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87427970","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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