The Experts below are selected from a list of 27714 Experts worldwide ranked by ideXlab platform
Denis Mangin - One of the best experts on this subject based on the ideXlab platform.
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thermodynamic study of a libr h2o absorption process for solar heat storage with crystallisation of the solution
Solar Energy, 2014Co-Authors: Kokouvi Edem Ntsoukpoe, Maxime Periermuzet, Nolwenn Le Pierres, Lingai Luo, Denis ManginAbstract:Abstract A heat storage process by absorption is studied in this paper. It is devoted to solar domestic systems. Energy and exergy studies are performed on the Ideal Cycle, and prove the contribution of the solution crystallisation to the system storage density, with an improvement of 22%, without degradation of the exergetic efficiency of the process. A prototype has been built and tested in conditions compatible with domestic solar thermal collectors. The process has been proved successful for heat storage. The heat charging was more efficient than the discharging phase, with respective heat transferred in the range of 1–2 kW and 0.3–0.5 kW, in typical solar domestic conditions. Crystallisation has been observed, and will increase the storage density but discrepancies were found between the Ideal solution and the global prototype crystallisation behaviour, possibly due to some impurities presence, corrosion products and a slow dissolution kinetic.
Yousef Haseli - One of the best experts on this subject based on the ideXlab platform.
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optimization of a regenerative brayton Cycle by maximization of a newly defined second law efficiency
Energy Conversion and Management, 2013Co-Authors: Yousef HaseliAbstract:Abstract The idea is to find out whether 2nd law efficiency optimization may be a suitable trade-off between maximum work output and maximum 1st law efficiency designs for a regenerative gas turbine engine operating on the basis of an open Brayton Cycle. The primary emphasis is placed on analyzing the Ideal Cycle to determine the upper limit of the engine. Explicit relationships are established for work and entropy production of the Ideal Cycle. To examine whether a Brayton Cycle may operate at the regime of fully reversible characterized by zero entropy generation condition, the Cycle net work is computed. It is shown that an Ideal Brayton-type engine with or without a regenerator cannot operate at fully reversible limit. Subsequently, the analysis is expanded to an irreversible Cycle and the relevant relationships are obtained for net work, thermal efficiency, total entropy production, and second law efficiency defined as the thermal efficiency of the irreversible Cycle divided by the thermal efficiency of the Ideal Cycle. The effects of the compressor and turbine efficiencies, regenerator effectiveness, pressure drop in the Cycle and the ratio of maximum-to-minimum Cycle temperature on optimum pressure ratios obtained by maximization of 1st and 2nd law efficiencies and work output are examined. The results indicate that for the regenerator effectiveness greater than 0.82, the 2nd law efficiency optimization may be considered as a trade-off between the maximum work output and the maximum 1st law efficiency.
Mengchao Chen - One of the best experts on this subject based on the ideXlab platform.
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transcritical carbon dioxide power Cycle for waste heat recovery a roadmap analysis from Ideal Cycle to real Cycle with case implementation
Energy Conversion and Management, 2020Co-Authors: Dongpeng Zhao, Li Zhao, Shuai Deng, Ruikai Zhao, Mengchao ChenAbstract:Abstract Waste heat recovery (WHR) is an important measure to improve the utilization efficiency of primary energy and alleviate the scarcity of fossil fuels, and converting thermal energy into electrical energy by means of thermodynamic Cycles is regarded as the best choice for WHR because of convenience in the use and transmission of electrical energy. Various thermodynamic Cycles have been constantly proposed and proved to be applicable for WHR, which has led to a controversy about the most suitable Cycles. Although some studies have proposed their own opinions by comparing the thermodynamic or economic performance of different Cycles, this controversy has not been completely resolved due to the lack of research from the perspective of the Ideal Cycle. Therefore, a new Ideal Cycle that could solve difficulties hidden in the implementation of existing Ideal Cycles is proposed in this study. And a real Cycle that includes over-expansion, recompression, and internal heat recovery is derived by gradually considering the real factors on the basis of the new Ideal Cycle. Then, to implement the above real Cycle, a modified transcritical carbon dioxide power Cycle is proposed to recover waste heat from the flue gas of 500 ℃. Thermodynamic analysis of the modified Cycle is carried out, and results show that the maximum net work output and corresponding heat recovery rate of flue gas reach 109.99 kW and 81.5% under the considered conditions. Compared with the traditional transcritical carbon dioxide power Cycle with recuperator, the net work output, heat recovery rate of flue gas, thermal efficiency, and exergy efficiency of the modified Cycle improves by 33.6%–192.3%, 28.6%–39.5%, 3.9%–109.5%, and 11.4%–122.3%, respectively, under the same conditions. This indicates that the modified Cycle performs better and the proposed Ideal Cycle can guide the research of WHR.
Kokouvi Edem Ntsoukpoe - One of the best experts on this subject based on the ideXlab platform.
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thermodynamic study of a libr h2o absorption process for solar heat storage with crystallisation of the solution
Solar Energy, 2014Co-Authors: Kokouvi Edem Ntsoukpoe, Maxime Periermuzet, Nolwenn Le Pierres, Lingai Luo, Denis ManginAbstract:Abstract A heat storage process by absorption is studied in this paper. It is devoted to solar domestic systems. Energy and exergy studies are performed on the Ideal Cycle, and prove the contribution of the solution crystallisation to the system storage density, with an improvement of 22%, without degradation of the exergetic efficiency of the process. A prototype has been built and tested in conditions compatible with domestic solar thermal collectors. The process has been proved successful for heat storage. The heat charging was more efficient than the discharging phase, with respective heat transferred in the range of 1–2 kW and 0.3–0.5 kW, in typical solar domestic conditions. Crystallisation has been observed, and will increase the storage density but discrepancies were found between the Ideal solution and the global prototype crystallisation behaviour, possibly due to some impurities presence, corrosion products and a slow dissolution kinetic.
Dongpeng Zhao - One of the best experts on this subject based on the ideXlab platform.
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transcritical carbon dioxide power Cycle for waste heat recovery a roadmap analysis from Ideal Cycle to real Cycle with case implementation
Energy Conversion and Management, 2020Co-Authors: Dongpeng Zhao, Li Zhao, Shuai Deng, Ruikai Zhao, Mengchao ChenAbstract:Abstract Waste heat recovery (WHR) is an important measure to improve the utilization efficiency of primary energy and alleviate the scarcity of fossil fuels, and converting thermal energy into electrical energy by means of thermodynamic Cycles is regarded as the best choice for WHR because of convenience in the use and transmission of electrical energy. Various thermodynamic Cycles have been constantly proposed and proved to be applicable for WHR, which has led to a controversy about the most suitable Cycles. Although some studies have proposed their own opinions by comparing the thermodynamic or economic performance of different Cycles, this controversy has not been completely resolved due to the lack of research from the perspective of the Ideal Cycle. Therefore, a new Ideal Cycle that could solve difficulties hidden in the implementation of existing Ideal Cycles is proposed in this study. And a real Cycle that includes over-expansion, recompression, and internal heat recovery is derived by gradually considering the real factors on the basis of the new Ideal Cycle. Then, to implement the above real Cycle, a modified transcritical carbon dioxide power Cycle is proposed to recover waste heat from the flue gas of 500 ℃. Thermodynamic analysis of the modified Cycle is carried out, and results show that the maximum net work output and corresponding heat recovery rate of flue gas reach 109.99 kW and 81.5% under the considered conditions. Compared with the traditional transcritical carbon dioxide power Cycle with recuperator, the net work output, heat recovery rate of flue gas, thermal efficiency, and exergy efficiency of the modified Cycle improves by 33.6%–192.3%, 28.6%–39.5%, 3.9%–109.5%, and 11.4%–122.3%, respectively, under the same conditions. This indicates that the modified Cycle performs better and the proposed Ideal Cycle can guide the research of WHR.
