The Experts below are selected from a list of 35643 Experts worldwide ranked by ideXlab platform
Giampaolo Manzolini - One of the best experts on this subject based on the ideXlab platform.
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comparison of two linear collectors in solar thermal plants parabolic trough versus fresnel
Journal of Solar Energy Engineering-transactions of The Asme, 2013Co-Authors: Andrea Giostri, Marco Binotti, Paolo Silva, Ennio Macchi, Giampaolo ManzoliniAbstract:Parabolic trough (PT) technology can be considered the state of the art for solar thermal power plants thanks to the almost 30 yr of experience gained in SEGS and, recently, Nevada Solar One plants in the United States and Andasol plant in Spain. One of the major issues that limits the wide diffusion of this technology is the high investment cost of the solar field and, particularly, of the solar collector. For this reason, research has focused on developing new solutions that aim to reduce costs. This paper compares, at nominal conditions, commercial Fresnel technology for direct steam generation with conventional parabolic trough technology based on Synthetic Oil as heat-transfer. The comparison addresses nominal conditions as well as annual average performance. In both technologies, no thermal storage system is considered. Performance is calculated by Thermoflex®, a commercial code, with a dedicated component to evaluate solar plant. Results will show that, at nominal conditions, Fresnel technology has an optical efficiency of 67%, which is lower than the 75% efficiency of the parabolic trough. Calculated net electric efficiency is about 19.25%, whereas PT technology achieves 23.6% efficiency. In off-design conditions, the performance gap between Fresnel and parabolic trough increases because the former is significantly affected by high incident angles of solar radiation. The calculated sun-to-electric annual average efficiency for a Fresnel plant is 10.2%, which is a consequence of the average optical efficiency of 38.8%; a parabolic trough achieves an overall efficiency of 16%, with an optical efficiency of 52.7%. An additional case with a Fresnel collector and Synthetic-Oil outlines the differences among the cases investigated. Since part of the performance difference between Fresnel and PT technologies is simply due to different definitions, we introduce additional indexes to make a consistent comparison. Finally, a simplified economic assessment shows that Fresnel collectors must reduce investment costs of at least 45% than parabolic trough to achieve the same levelized cost of electricity.
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comparison of different solar plants based on parabolic trough technology
Solar Energy, 2012Co-Authors: Andrea Giostri, Marco Binotti, Paolo Silva, Ennio Macchi, Marco Astolfi, Giampaolo ManzoliniAbstract:Abstract Solar thermal plants are among the most promising technologies to replace fossil fuel stationary applications, and within solar thermal technologies, parabolic troughs are considered the most mature application in the market. This paper compares different solar field technologies, in terms of both performance at design conditions and annual energy production; an in-house code, PATTO, was used to perform energy balances. We considered a reference case reflecting state-of-the-art Nevada Solar One, which showed a design efficiency and annual average efficiency of 22.4% and 15.3%, respectively, in agreement with actual performance. If solar salts are used as heat-transfer fluid instead of Synthetic Oil (e.g. ARCHIMEDE plant), the efficiency improved within the range of 6% due to the higher maximum temperature. Further thermodynamic advantages can be achieved with a direct steam generation plant; the main drawback is the more complex transient control and no commercially available storage systems. We propose the innovative Milan configuration, which combines advantages of direct steam evaporation and the use of a heat-transfer fluid, to investigate both Synthetic Oil and solar salts for steam superheating and reheating. Results for this configuration are very promising, with a sun-to-electric annual average efficiency of 17.8%, which is 16% higher than the reference case. Detailed daily simulations showed that advantages are more significant at low radiation. However, the plant should be optimized on an economic basis and we will discuss this in a future paper.
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comparison of two linear collectors in solar thermal plants parabolic trough vs fresnel
ASME 2011 5th International Conference on Energy Sustainability Parts A B and C, 2011Co-Authors: Andrea Giostri, Marco Binotti, Paolo Silva, Ennio Macchi, Giampaolo ManzoliniAbstract:Parabolic trough can be considered the state of the art for solar thermal power plants thanks to the almost 30 years experience gained in SEGS and, recently, Nevada Solar One plants in US and Andasol plants in Spain. One of the major issues that limits the wide diffusion of this technology is the high investment cost of the solar field and, particularly, of the solar collector. For this reason, since several years research activity has been trying to develop new solutions with the aim of cost reduction. This work compares commercial Fresnel technology with conventional parabolic trough plant based on Synthetic Oil as heat transfer fluid at nominal conditions and evaluates yearly average performances. In both technologies, no thermal storage system is considered. In addition, for Fresnel, a Direct Steam Generation (DSG) case is investigated. Performances are calculated by a commercial code, Thermoflex® , with dedicated component to evaluate solar plant. Results will show that, at nominal conditions, Fresnel technology have an optical efficiency of 67% which is lower than 75% of parabolic trough. Calculated net electric efficiency is about 19.25%, while parabolic trough technology achieves 23.6%. In off-design conditions, the gap between Fresnel and parabolic trough increases because the former is significantly affected by high radiation incident angles. The calculated sun-to-electric annual average efficiency for Fresnel plant is 10.2%, consequence of the average optical efficiency of 38.8%, while parabolic trough achieve an overall efficiency of 16%, with an optical one of 52.7%. An additional case with Fresnel collector and Synthetic Oil outlines differences among investigated cases. Finally, because part of performance difference between PT and Fresnel is simple due to different definitions, additional indexes are introduced in order to make a consistent comparison.© 2011 ASME
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solar thermodynamic plants for cogenerative industrial applications in southern europe
Renewable Energy, 2011Co-Authors: Giampaolo Manzolini, Ennio Macchi, M Bellarmino, Paolo SilvaAbstract:The paper deals with the preliminary design and optimization of cogenerative solar thermodynamic plants for industrial users. The considered plants are all based on proven parabolic trough technology, but different schemes have been analyzed: from a conventional configuration with indirect steam cycle and a heat transfer fluid such as Synthetic Oil or molten salts, to a more innovative arrangement with direct steam generation in the solar field. Thermodynamic parameters of the steam cycle have been optimized considering some constraints due to the heat requirements of the user, leading to a preliminary design of the main components of the system and an estimation of costs. Resulting net electric efficiency is about 10% for conventional Synthetic Oil plant, while 13% for innovative molten salts and DSG. A comparison with conventional solar thermodynamic systems for electricity production and photovoltaic power plants shows the economic and energetic benefits of the cogenerative solution. Cost of electricity for solar plant is cheaper of about 20 €/MWh than conventional solar power application. Moreover, heat recovery allows to achieve a further 50% of CO2 emission savings compared to reference solar plants for only electricity production.
H Price - One of the best experts on this subject based on the ideXlab platform.
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engineering aspects of a molten salt heat transfer fluid in a trough solar field
Energy, 2004Co-Authors: David Kearney, P Nava, Bruce Kelly, Ulf Herrmann, R Cable, James E Pacheco, R Mahoney, H Price, D Blake, N PotrovitzaAbstract:An evaluation was carried out to investigate the feasibility of utilizing a molten salt as the heat transfer fluid (HTF) and for thermal storage in a parabolic trough solar field to improve system performance and to reduce the levelized electricity cost. The operating large-scale solar parabolic trough plants in the USA currently use a high temperature Synthetic Oil in the solar field consisting of a eutectic mixture of biphenyl/diphenyl oxide. The scope of the overall investigation included examination of known critical issues, postulating solutions or possible approaches where potential problems existed, and the quantification of performance and electricity cost using preliminary, but reasonable, cost inputs. The two leading candidates were the so-called solar salt (a binary salt consisting of 60% NaNO3 and 40% KNO3) and a salt sold commercially as HitecXL (a ternary salt consisting of 48% Ca(NO3)2, 7% NaNO3, and 45% KNO3). Operation and maintenance (O&M) becomes an important concern with molten salt in the solar field. This paper addresses that concern, focusing on design and O&M issues associated with routine freeze protection, solar field preheat methods, collector loop maintenance and the selection of appropriate materials for piping and fittings.
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assessment of a molten salt heat transfer fluid in a parabolic trough solar field
Journal of Solar Energy Engineering-transactions of The Asme, 2003Co-Authors: David Kearney, P Nava, Bruce Kelly, Ulf Herrmann, R Cable, James E Pacheco, R Mahoney, N Potrovitza, Daniel M Blake, H PriceAbstract:An evaluation was carried out to investigate the feasibility of utilizing a molten salt as the heat transfer fluid (HTF) and for thermal storage in a parabolic trough solar field to improve system performance and to reduce the levelized electricity cost. The operating SEGS (Solar Electric Generating Systems located in Mojave Desert, California) plants currently use a high temperature Synthetic Oil consisting of a eutectic mixture of biphenyl/ diphenyl oxide. The scope of this investigation included examination of known critical issues, postulating solutions or possible approaches where potential problems exist, and the quantification of performance and electricity cost using preliminary cost inputs. The two leading candidates were the so-called solar salt (a binary salt consisting of 60% NaNO 3 and 40% KNO 3 ) and a salt sold commercially as HitecXL (a ternary salt consisting of 48% Ca(NO 3 ) 2 , 7% NaNO 3 , and 45% KNO 3 ). Assuming a two-tank storage system and a maximum operation temperature of 450°C, the evaluation showed that the levelized electricity cost can be reduced by 14.2% compared to a state-of-the-art parabolic trough plant such as the SEGS plants. If higher temperatures are possible, the improvement may be as high as 17.6%. Thermocline salt storage systems offer even greater benefits.
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evaluation of a molten salt heat transfer fluid in a parabolic trough solar field
Solar Energy, 2002Co-Authors: David Kearney, P Nava, Bruce Kelly, Ulf Herrmann, R Cable, James E Pacheco, R Mahoney, N Potrovitza, Daniel M Blake, H PriceAbstract:An evaluation was carried out to investigate the feasibility of utilizing a molten salt as the heat transfer fluid (HTF) and for thermal storage in a parabolic trough solar field to improve system performance and to reduce the levelized electricity cost. The operating SEGS plants currently use a high temperature Synthetic Oil consisting of a eutectic mixture of biphenyl/diphenyl oxide. The scope of this investigation included examination of known critical issues, postulating solutions or possible approaches where potential problems existed, and the quantification of performance and electricity cost using preliminary, but reasonable, cost inputs. The two leading candidates were the so-called solar salt (a binary salt consisting of 60% NaNO3 and 40% KNO3 ) and a salt sold commercially as HitecXL (a ternary salt consisting of 48% Ca(NO3 )2 , 7% NaNO3 , and 45% KNO3 ).Copyright © 2002 by ASME
Paolo Silva - One of the best experts on this subject based on the ideXlab platform.
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comparison of two linear collectors in solar thermal plants parabolic trough versus fresnel
Journal of Solar Energy Engineering-transactions of The Asme, 2013Co-Authors: Andrea Giostri, Marco Binotti, Paolo Silva, Ennio Macchi, Giampaolo ManzoliniAbstract:Parabolic trough (PT) technology can be considered the state of the art for solar thermal power plants thanks to the almost 30 yr of experience gained in SEGS and, recently, Nevada Solar One plants in the United States and Andasol plant in Spain. One of the major issues that limits the wide diffusion of this technology is the high investment cost of the solar field and, particularly, of the solar collector. For this reason, research has focused on developing new solutions that aim to reduce costs. This paper compares, at nominal conditions, commercial Fresnel technology for direct steam generation with conventional parabolic trough technology based on Synthetic Oil as heat-transfer. The comparison addresses nominal conditions as well as annual average performance. In both technologies, no thermal storage system is considered. Performance is calculated by Thermoflex®, a commercial code, with a dedicated component to evaluate solar plant. Results will show that, at nominal conditions, Fresnel technology has an optical efficiency of 67%, which is lower than the 75% efficiency of the parabolic trough. Calculated net electric efficiency is about 19.25%, whereas PT technology achieves 23.6% efficiency. In off-design conditions, the performance gap between Fresnel and parabolic trough increases because the former is significantly affected by high incident angles of solar radiation. The calculated sun-to-electric annual average efficiency for a Fresnel plant is 10.2%, which is a consequence of the average optical efficiency of 38.8%; a parabolic trough achieves an overall efficiency of 16%, with an optical efficiency of 52.7%. An additional case with a Fresnel collector and Synthetic-Oil outlines the differences among the cases investigated. Since part of the performance difference between Fresnel and PT technologies is simply due to different definitions, we introduce additional indexes to make a consistent comparison. Finally, a simplified economic assessment shows that Fresnel collectors must reduce investment costs of at least 45% than parabolic trough to achieve the same levelized cost of electricity.
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comparison of different solar plants based on parabolic trough technology
Solar Energy, 2012Co-Authors: Andrea Giostri, Marco Binotti, Paolo Silva, Ennio Macchi, Marco Astolfi, Giampaolo ManzoliniAbstract:Abstract Solar thermal plants are among the most promising technologies to replace fossil fuel stationary applications, and within solar thermal technologies, parabolic troughs are considered the most mature application in the market. This paper compares different solar field technologies, in terms of both performance at design conditions and annual energy production; an in-house code, PATTO, was used to perform energy balances. We considered a reference case reflecting state-of-the-art Nevada Solar One, which showed a design efficiency and annual average efficiency of 22.4% and 15.3%, respectively, in agreement with actual performance. If solar salts are used as heat-transfer fluid instead of Synthetic Oil (e.g. ARCHIMEDE plant), the efficiency improved within the range of 6% due to the higher maximum temperature. Further thermodynamic advantages can be achieved with a direct steam generation plant; the main drawback is the more complex transient control and no commercially available storage systems. We propose the innovative Milan configuration, which combines advantages of direct steam evaporation and the use of a heat-transfer fluid, to investigate both Synthetic Oil and solar salts for steam superheating and reheating. Results for this configuration are very promising, with a sun-to-electric annual average efficiency of 17.8%, which is 16% higher than the reference case. Detailed daily simulations showed that advantages are more significant at low radiation. However, the plant should be optimized on an economic basis and we will discuss this in a future paper.
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comparison of two linear collectors in solar thermal plants parabolic trough vs fresnel
ASME 2011 5th International Conference on Energy Sustainability Parts A B and C, 2011Co-Authors: Andrea Giostri, Marco Binotti, Paolo Silva, Ennio Macchi, Giampaolo ManzoliniAbstract:Parabolic trough can be considered the state of the art for solar thermal power plants thanks to the almost 30 years experience gained in SEGS and, recently, Nevada Solar One plants in US and Andasol plants in Spain. One of the major issues that limits the wide diffusion of this technology is the high investment cost of the solar field and, particularly, of the solar collector. For this reason, since several years research activity has been trying to develop new solutions with the aim of cost reduction. This work compares commercial Fresnel technology with conventional parabolic trough plant based on Synthetic Oil as heat transfer fluid at nominal conditions and evaluates yearly average performances. In both technologies, no thermal storage system is considered. In addition, for Fresnel, a Direct Steam Generation (DSG) case is investigated. Performances are calculated by a commercial code, Thermoflex® , with dedicated component to evaluate solar plant. Results will show that, at nominal conditions, Fresnel technology have an optical efficiency of 67% which is lower than 75% of parabolic trough. Calculated net electric efficiency is about 19.25%, while parabolic trough technology achieves 23.6%. In off-design conditions, the gap between Fresnel and parabolic trough increases because the former is significantly affected by high radiation incident angles. The calculated sun-to-electric annual average efficiency for Fresnel plant is 10.2%, consequence of the average optical efficiency of 38.8%, while parabolic trough achieve an overall efficiency of 16%, with an optical one of 52.7%. An additional case with Fresnel collector and Synthetic Oil outlines differences among investigated cases. Finally, because part of performance difference between PT and Fresnel is simple due to different definitions, additional indexes are introduced in order to make a consistent comparison.© 2011 ASME
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solar thermodynamic plants for cogenerative industrial applications in southern europe
Renewable Energy, 2011Co-Authors: Giampaolo Manzolini, Ennio Macchi, M Bellarmino, Paolo SilvaAbstract:The paper deals with the preliminary design and optimization of cogenerative solar thermodynamic plants for industrial users. The considered plants are all based on proven parabolic trough technology, but different schemes have been analyzed: from a conventional configuration with indirect steam cycle and a heat transfer fluid such as Synthetic Oil or molten salts, to a more innovative arrangement with direct steam generation in the solar field. Thermodynamic parameters of the steam cycle have been optimized considering some constraints due to the heat requirements of the user, leading to a preliminary design of the main components of the system and an estimation of costs. Resulting net electric efficiency is about 10% for conventional Synthetic Oil plant, while 13% for innovative molten salts and DSG. A comparison with conventional solar thermodynamic systems for electricity production and photovoltaic power plants shows the economic and energetic benefits of the cogenerative solution. Cost of electricity for solar plant is cheaper of about 20 €/MWh than conventional solar power application. Moreover, heat recovery allows to achieve a further 50% of CO2 emission savings compared to reference solar plants for only electricity production.
Ennio Macchi - One of the best experts on this subject based on the ideXlab platform.
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comparison of two linear collectors in solar thermal plants parabolic trough versus fresnel
Journal of Solar Energy Engineering-transactions of The Asme, 2013Co-Authors: Andrea Giostri, Marco Binotti, Paolo Silva, Ennio Macchi, Giampaolo ManzoliniAbstract:Parabolic trough (PT) technology can be considered the state of the art for solar thermal power plants thanks to the almost 30 yr of experience gained in SEGS and, recently, Nevada Solar One plants in the United States and Andasol plant in Spain. One of the major issues that limits the wide diffusion of this technology is the high investment cost of the solar field and, particularly, of the solar collector. For this reason, research has focused on developing new solutions that aim to reduce costs. This paper compares, at nominal conditions, commercial Fresnel technology for direct steam generation with conventional parabolic trough technology based on Synthetic Oil as heat-transfer. The comparison addresses nominal conditions as well as annual average performance. In both technologies, no thermal storage system is considered. Performance is calculated by Thermoflex®, a commercial code, with a dedicated component to evaluate solar plant. Results will show that, at nominal conditions, Fresnel technology has an optical efficiency of 67%, which is lower than the 75% efficiency of the parabolic trough. Calculated net electric efficiency is about 19.25%, whereas PT technology achieves 23.6% efficiency. In off-design conditions, the performance gap between Fresnel and parabolic trough increases because the former is significantly affected by high incident angles of solar radiation. The calculated sun-to-electric annual average efficiency for a Fresnel plant is 10.2%, which is a consequence of the average optical efficiency of 38.8%; a parabolic trough achieves an overall efficiency of 16%, with an optical efficiency of 52.7%. An additional case with a Fresnel collector and Synthetic-Oil outlines the differences among the cases investigated. Since part of the performance difference between Fresnel and PT technologies is simply due to different definitions, we introduce additional indexes to make a consistent comparison. Finally, a simplified economic assessment shows that Fresnel collectors must reduce investment costs of at least 45% than parabolic trough to achieve the same levelized cost of electricity.
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comparison of different solar plants based on parabolic trough technology
Solar Energy, 2012Co-Authors: Andrea Giostri, Marco Binotti, Paolo Silva, Ennio Macchi, Marco Astolfi, Giampaolo ManzoliniAbstract:Abstract Solar thermal plants are among the most promising technologies to replace fossil fuel stationary applications, and within solar thermal technologies, parabolic troughs are considered the most mature application in the market. This paper compares different solar field technologies, in terms of both performance at design conditions and annual energy production; an in-house code, PATTO, was used to perform energy balances. We considered a reference case reflecting state-of-the-art Nevada Solar One, which showed a design efficiency and annual average efficiency of 22.4% and 15.3%, respectively, in agreement with actual performance. If solar salts are used as heat-transfer fluid instead of Synthetic Oil (e.g. ARCHIMEDE plant), the efficiency improved within the range of 6% due to the higher maximum temperature. Further thermodynamic advantages can be achieved with a direct steam generation plant; the main drawback is the more complex transient control and no commercially available storage systems. We propose the innovative Milan configuration, which combines advantages of direct steam evaporation and the use of a heat-transfer fluid, to investigate both Synthetic Oil and solar salts for steam superheating and reheating. Results for this configuration are very promising, with a sun-to-electric annual average efficiency of 17.8%, which is 16% higher than the reference case. Detailed daily simulations showed that advantages are more significant at low radiation. However, the plant should be optimized on an economic basis and we will discuss this in a future paper.
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comparison of two linear collectors in solar thermal plants parabolic trough vs fresnel
ASME 2011 5th International Conference on Energy Sustainability Parts A B and C, 2011Co-Authors: Andrea Giostri, Marco Binotti, Paolo Silva, Ennio Macchi, Giampaolo ManzoliniAbstract:Parabolic trough can be considered the state of the art for solar thermal power plants thanks to the almost 30 years experience gained in SEGS and, recently, Nevada Solar One plants in US and Andasol plants in Spain. One of the major issues that limits the wide diffusion of this technology is the high investment cost of the solar field and, particularly, of the solar collector. For this reason, since several years research activity has been trying to develop new solutions with the aim of cost reduction. This work compares commercial Fresnel technology with conventional parabolic trough plant based on Synthetic Oil as heat transfer fluid at nominal conditions and evaluates yearly average performances. In both technologies, no thermal storage system is considered. In addition, for Fresnel, a Direct Steam Generation (DSG) case is investigated. Performances are calculated by a commercial code, Thermoflex® , with dedicated component to evaluate solar plant. Results will show that, at nominal conditions, Fresnel technology have an optical efficiency of 67% which is lower than 75% of parabolic trough. Calculated net electric efficiency is about 19.25%, while parabolic trough technology achieves 23.6%. In off-design conditions, the gap between Fresnel and parabolic trough increases because the former is significantly affected by high radiation incident angles. The calculated sun-to-electric annual average efficiency for Fresnel plant is 10.2%, consequence of the average optical efficiency of 38.8%, while parabolic trough achieve an overall efficiency of 16%, with an optical one of 52.7%. An additional case with Fresnel collector and Synthetic Oil outlines differences among investigated cases. Finally, because part of performance difference between PT and Fresnel is simple due to different definitions, additional indexes are introduced in order to make a consistent comparison.© 2011 ASME
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solar thermodynamic plants for cogenerative industrial applications in southern europe
Renewable Energy, 2011Co-Authors: Giampaolo Manzolini, Ennio Macchi, M Bellarmino, Paolo SilvaAbstract:The paper deals with the preliminary design and optimization of cogenerative solar thermodynamic plants for industrial users. The considered plants are all based on proven parabolic trough technology, but different schemes have been analyzed: from a conventional configuration with indirect steam cycle and a heat transfer fluid such as Synthetic Oil or molten salts, to a more innovative arrangement with direct steam generation in the solar field. Thermodynamic parameters of the steam cycle have been optimized considering some constraints due to the heat requirements of the user, leading to a preliminary design of the main components of the system and an estimation of costs. Resulting net electric efficiency is about 10% for conventional Synthetic Oil plant, while 13% for innovative molten salts and DSG. A comparison with conventional solar thermodynamic systems for electricity production and photovoltaic power plants shows the economic and energetic benefits of the cogenerative solution. Cost of electricity for solar plant is cheaper of about 20 €/MWh than conventional solar power application. Moreover, heat recovery allows to achieve a further 50% of CO2 emission savings compared to reference solar plants for only electricity production.
David Kearney - One of the best experts on this subject based on the ideXlab platform.
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engineering aspects of a molten salt heat transfer fluid in a trough solar field
Energy, 2004Co-Authors: David Kearney, P Nava, Bruce Kelly, Ulf Herrmann, R Cable, James E Pacheco, R Mahoney, H Price, D Blake, N PotrovitzaAbstract:An evaluation was carried out to investigate the feasibility of utilizing a molten salt as the heat transfer fluid (HTF) and for thermal storage in a parabolic trough solar field to improve system performance and to reduce the levelized electricity cost. The operating large-scale solar parabolic trough plants in the USA currently use a high temperature Synthetic Oil in the solar field consisting of a eutectic mixture of biphenyl/diphenyl oxide. The scope of the overall investigation included examination of known critical issues, postulating solutions or possible approaches where potential problems existed, and the quantification of performance and electricity cost using preliminary, but reasonable, cost inputs. The two leading candidates were the so-called solar salt (a binary salt consisting of 60% NaNO3 and 40% KNO3) and a salt sold commercially as HitecXL (a ternary salt consisting of 48% Ca(NO3)2, 7% NaNO3, and 45% KNO3). Operation and maintenance (O&M) becomes an important concern with molten salt in the solar field. This paper addresses that concern, focusing on design and O&M issues associated with routine freeze protection, solar field preheat methods, collector loop maintenance and the selection of appropriate materials for piping and fittings.
-
assessment of a molten salt heat transfer fluid in a parabolic trough solar field
Journal of Solar Energy Engineering-transactions of The Asme, 2003Co-Authors: David Kearney, P Nava, Bruce Kelly, Ulf Herrmann, R Cable, James E Pacheco, R Mahoney, N Potrovitza, Daniel M Blake, H PriceAbstract:An evaluation was carried out to investigate the feasibility of utilizing a molten salt as the heat transfer fluid (HTF) and for thermal storage in a parabolic trough solar field to improve system performance and to reduce the levelized electricity cost. The operating SEGS (Solar Electric Generating Systems located in Mojave Desert, California) plants currently use a high temperature Synthetic Oil consisting of a eutectic mixture of biphenyl/ diphenyl oxide. The scope of this investigation included examination of known critical issues, postulating solutions or possible approaches where potential problems exist, and the quantification of performance and electricity cost using preliminary cost inputs. The two leading candidates were the so-called solar salt (a binary salt consisting of 60% NaNO 3 and 40% KNO 3 ) and a salt sold commercially as HitecXL (a ternary salt consisting of 48% Ca(NO 3 ) 2 , 7% NaNO 3 , and 45% KNO 3 ). Assuming a two-tank storage system and a maximum operation temperature of 450°C, the evaluation showed that the levelized electricity cost can be reduced by 14.2% compared to a state-of-the-art parabolic trough plant such as the SEGS plants. If higher temperatures are possible, the improvement may be as high as 17.6%. Thermocline salt storage systems offer even greater benefits.
-
evaluation of a molten salt heat transfer fluid in a parabolic trough solar field
Solar Energy, 2002Co-Authors: David Kearney, P Nava, Bruce Kelly, Ulf Herrmann, R Cable, James E Pacheco, R Mahoney, N Potrovitza, Daniel M Blake, H PriceAbstract:An evaluation was carried out to investigate the feasibility of utilizing a molten salt as the heat transfer fluid (HTF) and for thermal storage in a parabolic trough solar field to improve system performance and to reduce the levelized electricity cost. The operating SEGS plants currently use a high temperature Synthetic Oil consisting of a eutectic mixture of biphenyl/diphenyl oxide. The scope of this investigation included examination of known critical issues, postulating solutions or possible approaches where potential problems existed, and the quantification of performance and electricity cost using preliminary, but reasonable, cost inputs. The two leading candidates were the so-called solar salt (a binary salt consisting of 60% NaNO3 and 40% KNO3 ) and a salt sold commercially as HitecXL (a ternary salt consisting of 48% Ca(NO3 )2 , 7% NaNO3 , and 45% KNO3 ).Copyright © 2002 by ASME
