Theoretical Study on CO_2 Transcritical Cycle Combined Ejector Cycle Refrigeration System

Mechanicalvapourcompressioncyclesaremainlyemployedinmostrefrigerationsystems .Chlorofluoro carbons(CFCs)orhydrochlorofluorocarbons(HCFCs)aregenerallyusedasrefrigerantsinthesesystemsdrivenbyelectricityfromburningfossilfuels ,whichresultsino zonedepletionduetotheleakageandpoorrecoveryofthoseman maderefrigerants,andglobalwarmingowingtoCO2 emissionfrom powerstationsandthereasonisthatCFCsorHCFCsarepowerfulgreenhousegases.Inaddition,otherenvironmentalissuesarealsocausedbytheNOx,SO2 andpartic…     

Comparison of sequential and simultaneous design and optimization in low-temperature liquefaction and gas separation processes

A great deal of attention has been paid to design and optimization of low-temperature liquefaction and gas separation problems over the past years, due to their difficult nature. In this paper, two approaches featuring sequential and simultaneous methods for selection and arrangement of sub-ambient separation systems and their associated refrigeration cycles are compared. The effect of ignoring heat integration within the separation system and between the separation and refrigeration systems is addressed as well as fixing the sequence order of separation. The optimization is carried out using two famous stochastic search methods i.e. Genetic Algorithm (GA) and Simulated Annealing (SA). Three case studies are examined to illustrate the significant differences between optimization results. Also, the design optimality is re-checked with respect to usage of different refrigerants and the resulting structure is verified by application of a comprehensive exergy analysis.     

汽车空调制冷剂R134a代换R12的研究

R12对大气臭氧层有强烈的腐蚀作用.而R134a是一种新型的环保制冷剂,为减少环境污染,可用R134a代换R12.根据对R134a和R12特性的对比分析,改进了空调压缩机、冷凝器、蒸发器、膨胀阀和其他附属部件的具体结构及参数设置,汽车空调制冷系统可得到优化.     

家用空调制冷剂物质流动态演化特征——以中国澳门特别行政区为例

由于制冷剂较高的臭氧层消耗潜势和气候变化影响,政府和公众对于制冷剂的重视程度正不断加深.《蒙特利尔议定书》虽从源头上限制了臭氧消耗类物质(ODS)的生产和使用,却忽略了ODS的产品生命周期过程中潜在的释放风险.基于物质流分析方法,本文构建了中国澳门特别行政区(以下简称澳门特区)家用空调制冷剂的动态分析框架,并从生命周期...