The Experts below are selected from a list of 177 Experts worldwide ranked by ideXlab platform
Mostafa H. Sharqawy - One of the best experts on this subject based on the ideXlab platform.
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second law analysis of reverse osmosis desalination plants an alternative design using pressure retarded osmosis
Energy, 2011Co-Authors: Mostafa H. Sharqawy, Syed M. Zubair, John H. LienhardAbstract:Abstract A second law analysis of a reverse osmosis desalination plant is carried out using reliable seawater Exergy formulation instead of a common model in literature that represents seawater as an ideal mixture of liquid water and solid sodium chloride. The analysis is performed using reverse osmosis desalination plant data and compared with results previously published using the ideal mixture model. It is demonstrated that the previous model has serious shortcomings, particularly with regard to calculation of the seawater Flow Exergy, the minimum work of separation, and the second law efficiency. The most up-to-date thermodynamic properties of seawater, as needed to conduct an Exergy analysis, are given as correlations in this paper. From this new analysis, it is found that the studied reverse osmosis desalination plant has very low second law efficiency (
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second law analysis of reverse osmosis desalination plants an alternative design using pressure retarded osmosis
Energy, 2011Co-Authors: Mostafa H. Sharqawy, Syed M. Zubair, John H. LienhardAbstract:A second law analysis of a reverse osmosis desalination plant is carried out using reliable seawater Exergy formulation instead of a common model in literature that represents seawater as an ideal mixture of liquid water and solid sodium chloride. The analysis is performed using reverse osmosis desalination plant data and compared with results previously published using the ideal mixture model. It is demonstrated that the previous model has serious shortcomings, particularly with regard to calculation of the seawater Flow Exergy, the minimum work of separation, and the second law efficiency. The most up-to-date thermodynamic properties of seawater, as needed to conduct an Exergy analysis, are given as correlations in this paper. From this new analysis, it is found that the studied reverse osmosis desalination plant has very low second law efficiency (<2%) even when using the available energy recovery systems. Therefore, an energy recovery system is proposed using the (PRO) pressure retarded osmotic method. The proposed alternative design has a second law efficiency of 20%, and the input power is reduced by 38% relative to original reverse osmosis system.
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on Exergy calculations of seawater with applications in desalination systems
International Journal of Thermal Sciences, 2011Co-Authors: Mostafa H. Sharqawy, John H. Lienhard, Syed M. ZubairAbstract:Exergy analysis is a powerful diagnostic tool in thermal systems performance evaluation. The use of such an analysis in seawater desalination processes is of growing importance to determine the sites of the highest irreversible losses. In the literature, Exergy analyses of seawater desalination systems have sometimes modeled seawater as sodium chloride solutions of equivalent salt content or salinity; however, such matching does not bring all important properties of the two solutions into agreement. Furthermore, a common model that represents seawater as an ideal mixture of liquid water and solid sodium chloride may have serious shortcomings. Therefore, in this paper, the most up-to-date thermodynamic properties of seawater, as needed to conduct an Exergy analysis, are given as correlations and tabulated data. The effect of the system properties as well as the environment dead state on the Exergy and Flow Exergy variation is investigated. In addition, an Exergy analysis for a large MSF distillation plant is performed using plant operating data and results previously published using the above-mentioned ideal mixture model. It is demonstrated that this ideal mixture model gives Flow Exergy values that are far from the correct ones. Moreover, the second law efficiency differs by about 80% for some cases.
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Formulation of Seawater Flow Exergy Using Accurate Thermodynamic Data
Volume 5: Energy Systems Analysis Thermodynamics and Sustainability; NanoEngineering for Energy; Engineering to Address Climate Change Parts A and B, 2010Co-Authors: Mostafa H. Sharqawy, John H. Lienhard, Syed M. ZubairAbstract:Seawater is a complex electrolyte solution of water and salts with sodium chloride as the major constituent. However, the thermodynamic properties of seawater are considerably different from those of aqueous sodium chloride solution. In the literature, Exergy analyses of seawater desalination systems have sometimes modeled seawater by sodium chloride solutions of equivalent salt content or salinity; however, such matching does not bring all important properties of the two solutions into agreement. Furthermore, some published studies attempt to represent sodium chloride solutions as a specific model for an ideal mixture of liquid water and solid sodium chloride, which is shown to have serious shortcomings. In this paper, the most up-to-date thermodynamic properties of seawater are compared with those of aqueous sodium chloride solution as well as the ideal mixture model. The Flow Exergy is calculated using various models and the results are compared. In addition, the minimum work required to desalinate a unit mass of fresh water from seawater of varying salinity is calculated using these models. The Flow Exergy calculated using the ideal mixture model in question is about 50% less than that of seawater. Accordingly, the minimum desalination work is underpredicted by about 50% when calculating it using that ideal mixture model. This consequently shows that Exergy analysis and the second law efficiency calculations performed using the ideal mixture model is comparatively far from the actual values.Copyright © 2010 by ASME
John H. Lienhard - One of the best experts on this subject based on the ideXlab platform.
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second law analysis of reverse osmosis desalination plants an alternative design using pressure retarded osmosis
Energy, 2011Co-Authors: Mostafa H. Sharqawy, Syed M. Zubair, John H. LienhardAbstract:Abstract A second law analysis of a reverse osmosis desalination plant is carried out using reliable seawater Exergy formulation instead of a common model in literature that represents seawater as an ideal mixture of liquid water and solid sodium chloride. The analysis is performed using reverse osmosis desalination plant data and compared with results previously published using the ideal mixture model. It is demonstrated that the previous model has serious shortcomings, particularly with regard to calculation of the seawater Flow Exergy, the minimum work of separation, and the second law efficiency. The most up-to-date thermodynamic properties of seawater, as needed to conduct an Exergy analysis, are given as correlations in this paper. From this new analysis, it is found that the studied reverse osmosis desalination plant has very low second law efficiency (
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second law analysis of reverse osmosis desalination plants an alternative design using pressure retarded osmosis
Energy, 2011Co-Authors: Mostafa H. Sharqawy, Syed M. Zubair, John H. LienhardAbstract:A second law analysis of a reverse osmosis desalination plant is carried out using reliable seawater Exergy formulation instead of a common model in literature that represents seawater as an ideal mixture of liquid water and solid sodium chloride. The analysis is performed using reverse osmosis desalination plant data and compared with results previously published using the ideal mixture model. It is demonstrated that the previous model has serious shortcomings, particularly with regard to calculation of the seawater Flow Exergy, the minimum work of separation, and the second law efficiency. The most up-to-date thermodynamic properties of seawater, as needed to conduct an Exergy analysis, are given as correlations in this paper. From this new analysis, it is found that the studied reverse osmosis desalination plant has very low second law efficiency (<2%) even when using the available energy recovery systems. Therefore, an energy recovery system is proposed using the (PRO) pressure retarded osmotic method. The proposed alternative design has a second law efficiency of 20%, and the input power is reduced by 38% relative to original reverse osmosis system.
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on Exergy calculations of seawater with applications in desalination systems
International Journal of Thermal Sciences, 2011Co-Authors: Mostafa H. Sharqawy, John H. Lienhard, Syed M. ZubairAbstract:Exergy analysis is a powerful diagnostic tool in thermal systems performance evaluation. The use of such an analysis in seawater desalination processes is of growing importance to determine the sites of the highest irreversible losses. In the literature, Exergy analyses of seawater desalination systems have sometimes modeled seawater as sodium chloride solutions of equivalent salt content or salinity; however, such matching does not bring all important properties of the two solutions into agreement. Furthermore, a common model that represents seawater as an ideal mixture of liquid water and solid sodium chloride may have serious shortcomings. Therefore, in this paper, the most up-to-date thermodynamic properties of seawater, as needed to conduct an Exergy analysis, are given as correlations and tabulated data. The effect of the system properties as well as the environment dead state on the Exergy and Flow Exergy variation is investigated. In addition, an Exergy analysis for a large MSF distillation plant is performed using plant operating data and results previously published using the above-mentioned ideal mixture model. It is demonstrated that this ideal mixture model gives Flow Exergy values that are far from the correct ones. Moreover, the second law efficiency differs by about 80% for some cases.
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Formulation of Seawater Flow Exergy Using Accurate Thermodynamic Data
Volume 5: Energy Systems Analysis Thermodynamics and Sustainability; NanoEngineering for Energy; Engineering to Address Climate Change Parts A and B, 2010Co-Authors: Mostafa H. Sharqawy, John H. Lienhard, Syed M. ZubairAbstract:Seawater is a complex electrolyte solution of water and salts with sodium chloride as the major constituent. However, the thermodynamic properties of seawater are considerably different from those of aqueous sodium chloride solution. In the literature, Exergy analyses of seawater desalination systems have sometimes modeled seawater by sodium chloride solutions of equivalent salt content or salinity; however, such matching does not bring all important properties of the two solutions into agreement. Furthermore, some published studies attempt to represent sodium chloride solutions as a specific model for an ideal mixture of liquid water and solid sodium chloride, which is shown to have serious shortcomings. In this paper, the most up-to-date thermodynamic properties of seawater are compared with those of aqueous sodium chloride solution as well as the ideal mixture model. The Flow Exergy is calculated using various models and the results are compared. In addition, the minimum work required to desalinate a unit mass of fresh water from seawater of varying salinity is calculated using these models. The Flow Exergy calculated using the ideal mixture model in question is about 50% less than that of seawater. Accordingly, the minimum desalination work is underpredicted by about 50% when calculating it using that ideal mixture model. This consequently shows that Exergy analysis and the second law efficiency calculations performed using the ideal mixture model is comparatively far from the actual values.Copyright © 2010 by ASME
Syed M. Zubair - One of the best experts on this subject based on the ideXlab platform.
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second law analysis of reverse osmosis desalination plants an alternative design using pressure retarded osmosis
Energy, 2011Co-Authors: Mostafa H. Sharqawy, Syed M. Zubair, John H. LienhardAbstract:Abstract A second law analysis of a reverse osmosis desalination plant is carried out using reliable seawater Exergy formulation instead of a common model in literature that represents seawater as an ideal mixture of liquid water and solid sodium chloride. The analysis is performed using reverse osmosis desalination plant data and compared with results previously published using the ideal mixture model. It is demonstrated that the previous model has serious shortcomings, particularly with regard to calculation of the seawater Flow Exergy, the minimum work of separation, and the second law efficiency. The most up-to-date thermodynamic properties of seawater, as needed to conduct an Exergy analysis, are given as correlations in this paper. From this new analysis, it is found that the studied reverse osmosis desalination plant has very low second law efficiency (
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second law analysis of reverse osmosis desalination plants an alternative design using pressure retarded osmosis
Energy, 2011Co-Authors: Mostafa H. Sharqawy, Syed M. Zubair, John H. LienhardAbstract:A second law analysis of a reverse osmosis desalination plant is carried out using reliable seawater Exergy formulation instead of a common model in literature that represents seawater as an ideal mixture of liquid water and solid sodium chloride. The analysis is performed using reverse osmosis desalination plant data and compared with results previously published using the ideal mixture model. It is demonstrated that the previous model has serious shortcomings, particularly with regard to calculation of the seawater Flow Exergy, the minimum work of separation, and the second law efficiency. The most up-to-date thermodynamic properties of seawater, as needed to conduct an Exergy analysis, are given as correlations in this paper. From this new analysis, it is found that the studied reverse osmosis desalination plant has very low second law efficiency (<2%) even when using the available energy recovery systems. Therefore, an energy recovery system is proposed using the (PRO) pressure retarded osmotic method. The proposed alternative design has a second law efficiency of 20%, and the input power is reduced by 38% relative to original reverse osmosis system.
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on Exergy calculations of seawater with applications in desalination systems
International Journal of Thermal Sciences, 2011Co-Authors: Mostafa H. Sharqawy, John H. Lienhard, Syed M. ZubairAbstract:Exergy analysis is a powerful diagnostic tool in thermal systems performance evaluation. The use of such an analysis in seawater desalination processes is of growing importance to determine the sites of the highest irreversible losses. In the literature, Exergy analyses of seawater desalination systems have sometimes modeled seawater as sodium chloride solutions of equivalent salt content or salinity; however, such matching does not bring all important properties of the two solutions into agreement. Furthermore, a common model that represents seawater as an ideal mixture of liquid water and solid sodium chloride may have serious shortcomings. Therefore, in this paper, the most up-to-date thermodynamic properties of seawater, as needed to conduct an Exergy analysis, are given as correlations and tabulated data. The effect of the system properties as well as the environment dead state on the Exergy and Flow Exergy variation is investigated. In addition, an Exergy analysis for a large MSF distillation plant is performed using plant operating data and results previously published using the above-mentioned ideal mixture model. It is demonstrated that this ideal mixture model gives Flow Exergy values that are far from the correct ones. Moreover, the second law efficiency differs by about 80% for some cases.
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Formulation of Seawater Flow Exergy Using Accurate Thermodynamic Data
Volume 5: Energy Systems Analysis Thermodynamics and Sustainability; NanoEngineering for Energy; Engineering to Address Climate Change Parts A and B, 2010Co-Authors: Mostafa H. Sharqawy, John H. Lienhard, Syed M. ZubairAbstract:Seawater is a complex electrolyte solution of water and salts with sodium chloride as the major constituent. However, the thermodynamic properties of seawater are considerably different from those of aqueous sodium chloride solution. In the literature, Exergy analyses of seawater desalination systems have sometimes modeled seawater by sodium chloride solutions of equivalent salt content or salinity; however, such matching does not bring all important properties of the two solutions into agreement. Furthermore, some published studies attempt to represent sodium chloride solutions as a specific model for an ideal mixture of liquid water and solid sodium chloride, which is shown to have serious shortcomings. In this paper, the most up-to-date thermodynamic properties of seawater are compared with those of aqueous sodium chloride solution as well as the ideal mixture model. The Flow Exergy is calculated using various models and the results are compared. In addition, the minimum work required to desalinate a unit mass of fresh water from seawater of varying salinity is calculated using these models. The Flow Exergy calculated using the ideal mixture model in question is about 50% less than that of seawater. Accordingly, the minimum desalination work is underpredicted by about 50% when calculating it using that ideal mixture model. This consequently shows that Exergy analysis and the second law efficiency calculations performed using the ideal mixture model is comparatively far from the actual values.Copyright © 2010 by ASME
Tomohiro Akiyama - One of the best experts on this subject based on the ideXlab platform.
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Storage of thermal energy for effective use of waste heat from industries
Journal of Materials Processing Technology, 1995Co-Authors: Jun-ichiro Yagi, Tomohiro AkiyamaAbstract:Abstract Energy saving is one of the most effective strategies to protect the global environmental conditions. At present, considerable amount of waste heat is emitted from metallurgical and chemical industries, which can be used not only for municipal purposes but also for industries if recovered. In this paper, fundamental studies on heat transfer was conducted for developing a heat storage process by latent heat for recovering the high temperature waste heat over 500 K. Heat transfer experiments were attempted for a single encapsulated phase change materials and for a packed bed. Six different materials were tested as PCM from the points of view of high energy density storage, chemical stability, non-toxicity and cost performance. Those were two inorganic and four metallic materials. A single capsule containing PCM was heated for heat storage and then cooled for heat release in nitrogen gas stream where convective heat transfer was predominant. The metal PCMs were found to be excellent for heat storage because of uniform temperature in the capsule. Heat transfer simulation was also conducted for a packed bed process of spherical capsules providing the fundamental informations on the optimal design. As a result, concurrent Flow for heat storage and release showed better result for effective use of storaged heat than counter-current Flow. Exergy efficiency was also evaluated.
Ibrahim Dincer - One of the best experts on this subject based on the ideXlab platform.
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thermodynamic performance assessment of a novel air cooling cycle maisotsenko cycle
International Journal of Refrigeration-revue Internationale Du Froid, 2011Co-Authors: Hakan Caliskan, Arif Hepbasli, Ibrahim Dincer, Valeriy MaisotsenkoAbstract:Abstract This study presents energy and Exergy analyses and sustainability assessment of the novel evaporative air cooling system based on Maisotsenko cycle which allows the product fluid to be cooled in to a dew point temperature of the incoming air. In the energy analysis, Maisotsenko cycle’s wet-bulb and dew point effectiveness, COP and primary energy ratio rates are calculated. Exergy analysis of the system is then carried out for six reference temperatures ranging from 0 °C to 23.88 °C as the incoming air (surrounding) temperature. The specific Flow Exergy, Exergy input, Exergy output, Exergy destruction, Exergy loss, Exergy efficiency, exergetic COP, primary Exergy ratio and entropy generation rates are determined for various cases. Furthermore, sustainability assessment is obtained using sustainability index method. As a result, maximum Exergy efficiency is found to be 19.14% for a reference temperature of 23.88 °C where the optimum operation takes place.
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Thermal modeling of a packed bed thermal energy storage system during charging
Applied Thermal Engineering, 2009Co-Authors: David Macphee, Ibrahim DincerAbstract:Abstract The process of charging of an encapsulated ice thermal energy storage device (ITES) is thermally modeled here through heat transfer and thermodynamic analyses. In heat transfer analysis, two different temperature profile cases, with negligible radial and/or stream-wise conduction are investigated for comparison, and the temperature profiles for each case are analyzed in an illustrative example. After obtaining temperature profiles through heat transfer analysis, a comprehensive thermodynamic study of the system is conducted. In this regard, energy, thermal Exergy and Flow Exergy efficiencies, internal and external irreversibilities corresponding to Flow Exergy, as well as charging times are investigated. The energy efficiencies are found to be more than 99%, whereas the thermal Exergy efficiencies are found to vary between 40% and 93% for viable charging times. The Flow Exergy efficiency varies between 48% and 88% for the Flows and inlet temperatures selected. For a Flow rate of 0.00164 m 3 /s, the maximum Flow Exergy efficiency occurs with an inlet temperature of 269.7 K, corresponding to an efficiency of 84.3%. For the case where the Flow rate is 0.0033 m 3 /s, the maximum Flow Exergy efficiency becomes 87.9% at an inlet temperature of 270.7 K. The results confirm the fact that energy analyses, and even thermal Exergy analyses, may lead to some unrealistic efficiency values. This could prove troublesome for designers wishing to optimize performance. For this reason, the Flow Exergy model provides the most useful information for those wishing to improve performance and reduce losses in such ITES systems.