In this study, the first and second laws of thermodynamics are used to analyze the performance of a single-stage absorption refrigeration system powered by solar energy. The working pair used in this study is LiBr-H2O...In this study, the first and second laws of thermodynamics are used to analyze the performance of a single-stage absorption refrigeration system powered by solar energy. The working pair used in this study is LiBr-H2O where water (H2O) is the refrigerant and the lithium bromide (LiBr) is the absorbent. A mathematical model based on exergy analysis is applied to analyse the system performance. Temperature, enthalpy, entropy, mass flow rate and exergy loss of each component including evacuated tube solar collector are evaluated. Furthermore, the overall coefficient of performance (COPcooling) and the overall exergetic coefficient of performance (ECOPcooling) of the solar absorption system (absorption system coupled to an evacuated tube solar collector) for cooling purpose are calculated from the thermodynamic properties of the working fluids under weather conditions of Ngaoundere city, Cameroon. The calculations were done on the basis of a half hourly analysis from 6:30 AM to 6:30 PM. The results were compared and they show that the exergy destruction highly occurs in the generator and the solar collector. The simulation results can be used for the thermodynamics optimization of solar absorption refrigeration systems.展开更多
A computer analysis of solar heating has been performed for Palestine. Results are presented for a prototype building using either fuel oil or gas under different heating loads in three climatic regions （Jordan valle...A computer analysis of solar heating has been performed for Palestine. Results are presented for a prototype building using either fuel oil or gas under different heating loads in three climatic regions （Jordan valley, coastal, and hilly）. Cumulative cost flows are compared for the life-cycle present value technique. Optimum design magnitudes are determined for maximum life-cycle savings. The payback period for capital invested in a solar system, and total savings are found for the optimum conditions. Variations of system performance are estimated. The effects of collector slope, proportionate storage tank volume, heat-exchanger parameters, and the design load on system performance are studied. Finally the economics of solar heating in Palestine are discussed and recommendations are made for increased utilization of solar energy.展开更多
This research paper aims to perform dynamics analysis,3E assessment including energy,exergy,exergoeconomic,and the multiobjective evolutionary optimization on a novel solar Li-Br absorption refrigeration cycle.The res...This research paper aims to perform dynamics analysis,3E assessment including energy,exergy,exergoeconomic,and the multiobjective evolutionary optimization on a novel solar Li-Br absorption refrigeration cycle.The research is time-dependent,owing to solar radiation variability during different timelines.Theoretically,all the necessary thermodynamic,energy,and exergy equations are applied initially.This is followed by the thermoeconomic analysis,which takes place after defining the designing variables during the thermoeconomic optimization process and is presented together with the economic relations of the system and its thermoeconomic characteristics.Furthermore,the sensitivity analysis is undertaken,the source of system inefficiency is determined,the multi-objective evolutionary optimization of the whole system is carried out,and the optimal values are compared with the primary stage.Engineering Equation Solver(EES)software has been used to accomplish comprehensive analyses.As part of the validation process,the results of the research are compared with those published previously and are found to be relatively consistent.展开更多
In this study,a parametric analysis was performed of a supercritical organic Rankine cycle driven by solar parabolic trough collectors(PTCs)coupled with a vapour-compression refrigeration cycle simultaneously for cool...In this study,a parametric analysis was performed of a supercritical organic Rankine cycle driven by solar parabolic trough collectors(PTCs)coupled with a vapour-compression refrigeration cycle simultaneously for cooling and power production.Thermal efficiency,exergy efficiency,exergy destruction and the coefficient of performance of the cogeneration system were considered to be performance parameters.A computer program was developed in engineering equation-solver software for analysis.Influences of the PTC design parameters(solar irradiation,solar-beam incidence angle and velocity of the heat-transfer fluid in the absorber tube),turbine inlet pressure,condenser and evaporator temperature on system performance were discussed.Furthermore,the performance of the cogeneration system was also compared with and without PTCs.It was concluded that it was necessary to design the PTCs carefully in order to achieve better cogeneration performance.The highest values of exergy efficiency,thermal efficiency and exergy destruction of the cogeneration system were 92.9%,51.13%and 1437 kW,respectively,at 0.95 kW/m2 of solar irradiation based on working fluid R227ea,but the highest coefficient of performance was found to be 2.278 on the basis of working fluid R134a.It was also obtained from the results that PTCs accounted for 76.32%of the total exergy destruction of the overall system and the cogeneration system performed well without considering solar performance.展开更多
文摘In this study, the first and second laws of thermodynamics are used to analyze the performance of a single-stage absorption refrigeration system powered by solar energy. The working pair used in this study is LiBr-H2O where water (H2O) is the refrigerant and the lithium bromide (LiBr) is the absorbent. A mathematical model based on exergy analysis is applied to analyse the system performance. Temperature, enthalpy, entropy, mass flow rate and exergy loss of each component including evacuated tube solar collector are evaluated. Furthermore, the overall coefficient of performance (COPcooling) and the overall exergetic coefficient of performance (ECOPcooling) of the solar absorption system (absorption system coupled to an evacuated tube solar collector) for cooling purpose are calculated from the thermodynamic properties of the working fluids under weather conditions of Ngaoundere city, Cameroon. The calculations were done on the basis of a half hourly analysis from 6:30 AM to 6:30 PM. The results were compared and they show that the exergy destruction highly occurs in the generator and the solar collector. The simulation results can be used for the thermodynamics optimization of solar absorption refrigeration systems.
文摘A computer analysis of solar heating has been performed for Palestine. Results are presented for a prototype building using either fuel oil or gas under different heating loads in three climatic regions （Jordan valley, coastal, and hilly）. Cumulative cost flows are compared for the life-cycle present value technique. Optimum design magnitudes are determined for maximum life-cycle savings. The payback period for capital invested in a solar system, and total savings are found for the optimum conditions. Variations of system performance are estimated. The effects of collector slope, proportionate storage tank volume, heat-exchanger parameters, and the design load on system performance are studied. Finally the economics of solar heating in Palestine are discussed and recommendations are made for increased utilization of solar energy.
基金supported by the National Natural Science Foundation of China(Grant No.52176016)。
文摘This research paper aims to perform dynamics analysis,3E assessment including energy,exergy,exergoeconomic,and the multiobjective evolutionary optimization on a novel solar Li-Br absorption refrigeration cycle.The research is time-dependent,owing to solar radiation variability during different timelines.Theoretically,all the necessary thermodynamic,energy,and exergy equations are applied initially.This is followed by the thermoeconomic analysis,which takes place after defining the designing variables during the thermoeconomic optimization process and is presented together with the economic relations of the system and its thermoeconomic characteristics.Furthermore,the sensitivity analysis is undertaken,the source of system inefficiency is determined,the multi-objective evolutionary optimization of the whole system is carried out,and the optimal values are compared with the primary stage.Engineering Equation Solver(EES)software has been used to accomplish comprehensive analyses.As part of the validation process,the results of the research are compared with those published previously and are found to be relatively consistent.
基金support of Department of Mechanical,Industrial&Production,Automobile Engineering of the Delhi Technological University,New Delhi,India.
文摘In this study,a parametric analysis was performed of a supercritical organic Rankine cycle driven by solar parabolic trough collectors(PTCs)coupled with a vapour-compression refrigeration cycle simultaneously for cooling and power production.Thermal efficiency,exergy efficiency,exergy destruction and the coefficient of performance of the cogeneration system were considered to be performance parameters.A computer program was developed in engineering equation-solver software for analysis.Influences of the PTC design parameters(solar irradiation,solar-beam incidence angle and velocity of the heat-transfer fluid in the absorber tube),turbine inlet pressure,condenser and evaporator temperature on system performance were discussed.Furthermore,the performance of the cogeneration system was also compared with and without PTCs.It was concluded that it was necessary to design the PTCs carefully in order to achieve better cogeneration performance.The highest values of exergy efficiency,thermal efficiency and exergy destruction of the cogeneration system were 92.9%,51.13%and 1437 kW,respectively,at 0.95 kW/m2 of solar irradiation based on working fluid R227ea,but the highest coefficient of performance was found to be 2.278 on the basis of working fluid R134a.It was also obtained from the results that PTCs accounted for 76.32%of the total exergy destruction of the overall system and the cogeneration system performed well without considering solar performance.
