The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Yiping Dai - One of the best experts on this subject based on the ideXlab platform.
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multi objective optimization of an organic rankine cycle orc for low grade waste heat recovery using evolutionary algorithm
Energy Conversion and Management, 2013Co-Authors: Jiangfeng Wang, Zhequan Yan, Man Wang, Yiping DaiAbstract:Abstract Organic Rankine cycle (ORC) can effectively recover low grade waste heat due to its excellent thermodynamic performance. Based on the examinations of the effects of key thermodynamic parameters on the exergy efficiency and overall capital cost, multi-objective optimization of the ORC with R134a as working fluid is conducted to achieve the system optimization design from both thermodynamic and economic aspects using Non-dominated sorting genetic algorithm-II (NSGA-II). The exergy efficiency and overall capital cost are selected as two objective functions to maximize the exergy efficiency and minimize the overall capital cost under the given waste heat conditions. Turbine inlet pressure, turbine inlet Temperature, pinch Temperature difference, approach Temperature difference and Condenser Temperature difference are selected as the decision variables owing to their significant effects on the exergy efficiency and overall capital cost. A Pareto frontier obtained shows that an increase in the exergy efficiency can increase the overall capital cost of the ORC system. The optimum design solution with their corresponding decision variables is selected from the Pareto frontier. The optimum exergy efficiency and overall capital cost are 13.98% and 129.28 × 10 4 USD, respectively, under the given waste heat conditions.
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parametric analysis for a new combined power and ejector absorption refrigeration cycle
Energy, 2009Co-Authors: Jiangfeng Wang, Yiping Dai, Taiyong ZhangAbstract:Abstract A new combined power and ejector–absorption refrigeration cycle is proposed, which combines the Rankine cycle and the ejector–absorption refrigeration cycle, and could produce both power output and refrigeration output simultaneously. This combined cycle, which originates from the cycle proposed by authors previously, introduces an ejector between the rectifier and the Condenser, and provides a performance improvement without greatly increasing the complexity of the system. A parametric analysis is conducted to evaluate the effects of the key thermodynamic parameters on the cycle performance. It is shown that heat source Temperature, Condenser Temperature, evaporator Temperature, turbine inlet pressure, turbine inlet Temperature, and basic solution ammonia concentration have significant effects on the net power output, refrigeration output and exergy efficiency of the combined cycle. It is evident that the ejector can improve the performance of the combined cycle proposed by authors previously.
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a theoretical study on a novel combined power and ejector refrigeration cycle
International Journal of Refrigeration-revue Internationale Du Froid, 2009Co-Authors: Jiangfeng Wang, Yiping Dai, Zhixin SunAbstract:A new combined power and refrigeration cycle is proposed for the cogeneration, which combines the Rankine cycle and the ejector refrigeration cycle by adding an extraction turbine between heat recovery vapor generator (HRVG) and ejector. This combined cycle could produce both power output and refrigeration output simultaneously, and could be driven by the flue gas from gas turbine or engine, solar energy, geothermal energy and industrial waste heats. Parametric analysis and exergy analysis are conducted to examine the effects of thermodynamic parameters on the performance and exergy destruction in each component for the combined cycle. The results show that the Condenser Temperature, the evaporator Temperature, the turbine inlet pressure, the turbine extraction pressure and extraction ratio have significant effects on the turbine power output, refrigeration output, exergy efficiency and exergy destruction in each component in the combined cycle. It is also shown that the biggest exergy destruction occurs in the heat recovery vapor generator, followed by the ejector and turbine.
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exergy analysis parametric analysis and optimization for a novel combined power and ejector refrigeration cycle
Applied Thermal Engineering, 2009Co-Authors: Yiping Dai, Jiangfeng Wang, Lin GaoAbstract:A new combined power and refrigeration cycle is proposed, which combines the Rankine cycle and the ejector refrigeration cycle. This combined cycle produces both power output and refrigeration output simultaneously. It can be driven by the flue gas of gas turbine or engine, solar energy, geothermal energy and industrial waste heats. An exergy analysis is performed to guide the thermodynamic improvement for this cycle. And a parametric analysis is conducted to evaluate the effects of the key thermodynamic parameters on the performance of the combined cycle. In addition, a parameter optimization is achieved by means of genetic algorithm to reach the maximum exergy efficiency. The results show that the biggest exergy loss due to the irreversibility occurs in heat addition processes, and the ejector causes the next largest exergy loss. It is also shown that the turbine inlet pressure, the turbine back pressure, the Condenser Temperature and the evaporator Temperature have significant effects on the turbine power output, refrigeration output and exergy efficiency of the combined cycle. The optimized exergy efficiency is 27.10% under the given condition.
Ilhan Ozturk - One of the best experts on this subject based on the ideXlab platform.
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thermoeconomic optimization of libr h2o r134a compression absorption cascade refrigeration cycle
Applied Thermal Engineering, 2015Co-Authors: Canan Cimsit, Ilhan Ozturk, Olcay KincayAbstract:This study presents the thermoeconomic optimization of LiBr/H2O-R134a compression-absorption cascade refrigeration cycle. The detailed exergy-based thermoeconomic analyses, thermoeconomic evaluation with exergoeconomic variables, and thermoeconomic optimization by using non-linear simplex direct search method have been performed for the cascade refrigeration cycle. In the sample application, the thermoeconomic optimization reveals the optimum generator Temperature, Condenser Temperature, absorber Temperature, Condenser Temperature of vapour compression section, effectiveness of solution heat exchanger and compressor isentropic efficiency. This analysis points out that the evaporator equipage and solution heat exchanger should be designed carefully according to the exergoeconomic factor values. The exergetic efficiency and minimum cost of objective function are determined as 7.30% and 4.05 ($/h) for the optimum case of sample application. The minimum cost of objective function is reduced about 3.3%, the coefficient of performance (COPcyclegen) and exergetic efficiency of cascade cycle are improved about 7% and 3.1% respectively, according to the base case.
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analysis of compression absorption cascade refrigeration cycles
Applied Thermal Engineering, 2012Co-Authors: Canan Cimsit, Ilhan OzturkAbstract:Abstract In this study, LiBr–H2O pair was used for the first time for absorption section of compression–absorption cascade refrigeration cycles. These cycles were analyzed theoretically and compared with using different refrigerants in the compression and absorption sections. While LiBr–H2O and NH3–H2O are used as fluid pair in cascade absorption section, R134a, R-410A and NH3 fluids were used in the vapour compression section of cascade cycle. It was presented that electrical energy consumption in the cascade refrigeration cycle is 48–51% lower than classical vapour compression refrigeration cycles that use R134a, R-410A and NH3 as working fluids under the same operating conditions, that are an evaporator Temperature of 263 K and a Condenser Temperature of 313 K. Separately the results show that by using LiBr–H2O pair for absorption section the thermal energy consumption of cascade refrigeration cycle could be reduced by 35% and also general coefficient of performance (COPcyclegen) could be improved by 33% compared to the NH3–H2O pair.
Jiangfeng Wang - One of the best experts on this subject based on the ideXlab platform.
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thermodynamic analysis and optimization of a solar powered transcritical co2 carbon dioxide power cycle for reverse osmosis desalination based on the recovery of cryogenic energy of lng liquefied natural gas
Energy, 2014Co-Authors: Guanghui Xia, Jiangfeng Wang, Qingxuan Sun, Xu Cao, Laisheng WangAbstract:Abstract A solar-powered transcritical CO2 (carbon dioxide) power cycle for reverse osmosis desalination based on the recovery of cryogenic energy of LNG (liquefied natural gas) is proposed. The system consists of a solar collector subsystem, a transcritical CO2 power cycle subsystem, a LNG subsystem and a RO (reverse osmosis) desalination subsystem. A thermal storage unit is introduced into the system to guarantee continuous and stable operation of the system. A mathematical model is developed to simulate the system based on several assumptions. The effects of several key thermodynamic parameters on the system performance are examined based on the performance criteria, including daily exergy efficiency, daily mechanical work output and daily fresh work output. Parametric optimization is conducted by genetic algorithm to maximize the daily fresh water output. The results show that the CO2 turbine inlet pressure has an optimal value to reach the daily maximum exergy efficiency under the given conditions. The daily exergy efficiency could decrease with an increase in Condenser Temperature, and increase with an increase in mass flow rate of oil and NG turbine inlet pressure. Through parametric optimization, the system can reach the daily exergy efficiency of 4.90% and provide 2537.33 m3 fresh water per day under the given conditions.
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multi objective optimization of an organic rankine cycle orc for low grade waste heat recovery using evolutionary algorithm
Energy Conversion and Management, 2013Co-Authors: Jiangfeng Wang, Zhequan Yan, Man Wang, Yiping DaiAbstract:Abstract Organic Rankine cycle (ORC) can effectively recover low grade waste heat due to its excellent thermodynamic performance. Based on the examinations of the effects of key thermodynamic parameters on the exergy efficiency and overall capital cost, multi-objective optimization of the ORC with R134a as working fluid is conducted to achieve the system optimization design from both thermodynamic and economic aspects using Non-dominated sorting genetic algorithm-II (NSGA-II). The exergy efficiency and overall capital cost are selected as two objective functions to maximize the exergy efficiency and minimize the overall capital cost under the given waste heat conditions. Turbine inlet pressure, turbine inlet Temperature, pinch Temperature difference, approach Temperature difference and Condenser Temperature difference are selected as the decision variables owing to their significant effects on the exergy efficiency and overall capital cost. A Pareto frontier obtained shows that an increase in the exergy efficiency can increase the overall capital cost of the ORC system. The optimum design solution with their corresponding decision variables is selected from the Pareto frontier. The optimum exergy efficiency and overall capital cost are 13.98% and 129.28 × 10 4 USD, respectively, under the given waste heat conditions.
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parametric analysis for a new combined power and ejector absorption refrigeration cycle
Energy, 2009Co-Authors: Jiangfeng Wang, Yiping Dai, Taiyong ZhangAbstract:Abstract A new combined power and ejector–absorption refrigeration cycle is proposed, which combines the Rankine cycle and the ejector–absorption refrigeration cycle, and could produce both power output and refrigeration output simultaneously. This combined cycle, which originates from the cycle proposed by authors previously, introduces an ejector between the rectifier and the Condenser, and provides a performance improvement without greatly increasing the complexity of the system. A parametric analysis is conducted to evaluate the effects of the key thermodynamic parameters on the cycle performance. It is shown that heat source Temperature, Condenser Temperature, evaporator Temperature, turbine inlet pressure, turbine inlet Temperature, and basic solution ammonia concentration have significant effects on the net power output, refrigeration output and exergy efficiency of the combined cycle. It is evident that the ejector can improve the performance of the combined cycle proposed by authors previously.
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a theoretical study on a novel combined power and ejector refrigeration cycle
International Journal of Refrigeration-revue Internationale Du Froid, 2009Co-Authors: Jiangfeng Wang, Yiping Dai, Zhixin SunAbstract:A new combined power and refrigeration cycle is proposed for the cogeneration, which combines the Rankine cycle and the ejector refrigeration cycle by adding an extraction turbine between heat recovery vapor generator (HRVG) and ejector. This combined cycle could produce both power output and refrigeration output simultaneously, and could be driven by the flue gas from gas turbine or engine, solar energy, geothermal energy and industrial waste heats. Parametric analysis and exergy analysis are conducted to examine the effects of thermodynamic parameters on the performance and exergy destruction in each component for the combined cycle. The results show that the Condenser Temperature, the evaporator Temperature, the turbine inlet pressure, the turbine extraction pressure and extraction ratio have significant effects on the turbine power output, refrigeration output, exergy efficiency and exergy destruction in each component in the combined cycle. It is also shown that the biggest exergy destruction occurs in the heat recovery vapor generator, followed by the ejector and turbine.
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exergy analysis parametric analysis and optimization for a novel combined power and ejector refrigeration cycle
Applied Thermal Engineering, 2009Co-Authors: Yiping Dai, Jiangfeng Wang, Lin GaoAbstract:A new combined power and refrigeration cycle is proposed, which combines the Rankine cycle and the ejector refrigeration cycle. This combined cycle produces both power output and refrigeration output simultaneously. It can be driven by the flue gas of gas turbine or engine, solar energy, geothermal energy and industrial waste heats. An exergy analysis is performed to guide the thermodynamic improvement for this cycle. And a parametric analysis is conducted to evaluate the effects of the key thermodynamic parameters on the performance of the combined cycle. In addition, a parameter optimization is achieved by means of genetic algorithm to reach the maximum exergy efficiency. The results show that the biggest exergy loss due to the irreversibility occurs in heat addition processes, and the ejector causes the next largest exergy loss. It is also shown that the turbine inlet pressure, the turbine back pressure, the Condenser Temperature and the evaporator Temperature have significant effects on the turbine power output, refrigeration output and exergy efficiency of the combined cycle. The optimized exergy efficiency is 27.10% under the given condition.
Canan Cimsit - One of the best experts on this subject based on the ideXlab platform.
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thermoeconomic optimization of libr h2o r134a compression absorption cascade refrigeration cycle
Applied Thermal Engineering, 2015Co-Authors: Canan Cimsit, Ilhan Ozturk, Olcay KincayAbstract:This study presents the thermoeconomic optimization of LiBr/H2O-R134a compression-absorption cascade refrigeration cycle. The detailed exergy-based thermoeconomic analyses, thermoeconomic evaluation with exergoeconomic variables, and thermoeconomic optimization by using non-linear simplex direct search method have been performed for the cascade refrigeration cycle. In the sample application, the thermoeconomic optimization reveals the optimum generator Temperature, Condenser Temperature, absorber Temperature, Condenser Temperature of vapour compression section, effectiveness of solution heat exchanger and compressor isentropic efficiency. This analysis points out that the evaporator equipage and solution heat exchanger should be designed carefully according to the exergoeconomic factor values. The exergetic efficiency and minimum cost of objective function are determined as 7.30% and 4.05 ($/h) for the optimum case of sample application. The minimum cost of objective function is reduced about 3.3%, the coefficient of performance (COPcyclegen) and exergetic efficiency of cascade cycle are improved about 7% and 3.1% respectively, according to the base case.
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analysis of compression absorption cascade refrigeration cycles
Applied Thermal Engineering, 2012Co-Authors: Canan Cimsit, Ilhan OzturkAbstract:Abstract In this study, LiBr–H2O pair was used for the first time for absorption section of compression–absorption cascade refrigeration cycles. These cycles were analyzed theoretically and compared with using different refrigerants in the compression and absorption sections. While LiBr–H2O and NH3–H2O are used as fluid pair in cascade absorption section, R134a, R-410A and NH3 fluids were used in the vapour compression section of cascade cycle. It was presented that electrical energy consumption in the cascade refrigeration cycle is 48–51% lower than classical vapour compression refrigeration cycles that use R134a, R-410A and NH3 as working fluids under the same operating conditions, that are an evaporator Temperature of 263 K and a Condenser Temperature of 313 K. Separately the results show that by using LiBr–H2O pair for absorption section the thermal energy consumption of cascade refrigeration cycle could be reduced by 35% and also general coefficient of performance (COPcyclegen) could be improved by 33% compared to the NH3–H2O pair.
A. Mani - One of the best experts on this subject based on the ideXlab platform.
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experimental studies on desalination system for ocean thermal energy utilisation
Desalination, 2007Co-Authors: Senthil R Kumar, A. Mani, S KumaraswamyAbstract:Abstract A desalination system has been designed for converting brackish water into potable water utilizing ocean thermal gradient. The desalination plant evaporates the water by flash and surface evaporation and subsequently the vapour is condensed to get potable water. An experimental plant with a capacity of 20 lph was designed for a typical ocean thermal gradient. The designed operating conditions of the plant are evaporator Temperature, 30°C and Condenser Temperature, 10°C. Experimental performance of the system was evaluated by varying the Condenser and evaporator Temperatures and chamber vacuum pressure.
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experimental investigation on r134a vapour ejector refrigeration system
International Journal of Refrigeration-revue Internationale Du Froid, 2006Co-Authors: A Selvaraju, A. ManiAbstract:The experimental investigation of the performance of a vapour ejector refrigeration system is described. The system uses R134a as working fluid and has a rated cooling capacity of 0.5 kW. The influence of generator, evaporator and Condenser Temperatures on the system performance is studied. This kind of system can be operated with low grade thermal energy such as solar energy, waste heat, etc. The operating conditions are chosen accordingly as, generator Temperature between 338 K and 363 K, Condenser Temperature between 299 K and 310.5 K, and evaporator Temperature between 275 K and 285.5 K. Six configurations of ejectors of different geometrical dimensions are selected for the parametric study. The performance of the refrigeration system at different operating Temperatures is presented.
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Experimental studies on an ammonia ejector refrigeration system
International Communications in Heat and Mass Transfer, 2006Co-Authors: T. Sankarlal, A. ManiAbstract:An ejector refrigeration system has been designed and developed to operate with a simulated (electric) heat source, which can be realized in practical applications by renewable energy sources like solar energy, geothermal energy, etc., or waste heat. In this paper, an experimental study on an ejector refrigeration system working with ammonia is presented. The influence of the generator, Condenser, and evaporator Temperatures on the ejector refrigeration system performance is presented. The entrainment ratio and COP of the system increase with increasing generator and evaporator Temperatures and decrease with increasing Condenser Temperature.
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analysis of a jet pump assisted vacuum desalination system using power plant waste heat
Desalination, 2005Co-Authors: Senthil R Kumar, A. Mani, Sivasailam KumaraswamyAbstract:With ever-increasing population and rapid growth of industrialization, there is a great demand for fresh water, especially for drinking, as natural resources are becoming limited. In view of the above, different desalination technologies are evolving with a thrust for utilization of renewable energy sources like solar energy, ocean thermal energy, geothermal energy and waste heat. Vacuum desalination is one such technology in which fresh water is produced from brackish water by evaporation and subsequent condensation. This desalination technique involves different processes like pressurization of brackish water by a pump, creation and maintenance of a vacuum using jet pumps, and evaporation of brackish water at reduced pressure using waste heat from a power plant such as water from Condenser. In this paper an analysis of a vacuum desalination system is presented. By applying the mass, momentum and energy balances across the various components, the governing equations are obtained for the analysis. These equations are solved using simulation. Validation of the simulated performance is made with the experimental data available in the literature. The study was carried out by varying operational parameters such as evaporator Temperature, Condenser Temperature, evaporator flow rate, Condenser flow rate and chamber pressure. Yield of fresh water obtained from the system increased as Condenser Temperature decreased and the evaporator Temperature increased. Further, the yield increased as chamber pressure decreased.