Research On Performance Of Dual-pressure Evaporative Jet Refrigeration Combined Power And Cooling System

With the rapid development of modern society and the acceleration of industrialization,there is usually a large amount of low-grade waste heat in the process of industrial production.If it can be recycled and reused with appropriate technology,it will not only increase the energy efficiency in the production process,but also Conducive to environmental protection.In this paper,a dual-pressure evaporative pressure organic Rankine cycle and an ejector refrigeration cycle are combined to construct a dualpressure evaporative ORC pumped-air ejection power-cooling cogeneration system(DORC/VERC)and a dual-pressure evaporating ORC liquid ejection power-cooling cogeneration system(DORC/LERC),to provide an effective way for the efficient utilization of low-grade waste heat.Combining basic thermal theory and technical and economic analysis methods,mathematical models for the main performance simulation of the two power and cooling cogeneration systems were established,and the models were numerically solved,and the genetic algorithm was used to optimize the two systems.At the same time,the circulating working fluids of the two systems are optimized.The analysis of DPORC/VERC shows that:Under the set working conditions,the net output power of the system is 7.95 k W,the cooling capacity is 5.86 k W,the thermal efficiency and the exergy efficiency are15.30% and 34.06%,respectively,and the total product cost is 116.13$/MWh.At this time,the exergy loss distribution is large.The components are in order of low-pressure generator,high-pressure generator,ejector and turbine;analysis of its key parameters surface: the increase of high-pressure generation temperature is beneficial to the overall improvement of the system performance,while the increase of low-pressure generation temperature is not conducive to the overall system The increase of efficiency;the increase of heat source temperature is beneficial to the total output energy and economy of the system,but its economy is not used,and the lower condensing temperature is beneficial to the improvement of the overall performance of the system;the increase of dryness is not conducive to the thermal performance of the system And economy;the increase of the air extraction rate is beneficial to the thermal efficiency and cooling capacity of the system,but at the same time it will have a negative impact on the net output power,exergy efficiency and overall product cost(SUCP)of the system,so its existence is at the best value.Under the condition of constructing multi-objective function and genetic algorithm to optimize the system,under the optimization result,the net output of the system is 10.65 k W,the cooling capacity is 2.59 k W,the thermal efficiency is 13.57%,the exergy efficiency is 24.06%,and the total product cost is 100.07$/MWh.The analysis of DPORC/LERC shows that:Under the set working conditions,the cooling capacity and net output power of the system are 0.24 k W and 9.23 k W,while the thermal efficiency and exergy efficiency of the system are 12.72% and 40.22%,respectively,and the total product cost is103.70$/MWh.The analysis of its key parameters shows that for the net output work of the system with higher high pressure generation temperature,thermal efficiency,exergy efficiency and economy are all beneficial.At the same time,the rise of low pressure generation temperature and the decrease of condensation temperature will help improve the system’s performance.Thermodynamic performance and economic performance;the increase of heat source temperature is conducive to the total output energy and economy of the system,but the exergy efficiency of the system will be negatively affected at this time;the higher dryness of the gas-liquid separator is conducive to the net output power,Exhaust efficiency and system economy,but the cooling capacity and thermal efficiency of the system are reduced at this time;although the increase in the pumping rate is conducive to the output cooling capacity of the system,the thermal performance and economic performance of the system will deteriorate at this time.Under the condition of constructing multi-objective function and genetic algorithm to optimize the system,under the optimization result,the net output of the system is 9.50 k W,the cooling capacity is 1.02 k W,the thermal efficiency is 15.96%,the exergy efficiency is 49.92%,and the total product cost is 101.93 $/MWh.The optimization results of circulating working fluids show that: for the DPORC/VERC system,the maximum thermal efficiency and maximum exergy efficiency correspond to R600,and the minimum unit product total cost corresponds to R600a;for the DPORC/LERC system,the maximum thermal efficiency,maximum exergy efficiency,and minimum The corresponding working fluid for the unit product total cost is R600..