【摘要】 将单级蒸气压缩式制冷系统作为冷冻消融设备的预冷系统,利用热力学第一定律、第二定律对其建立数学模型,进行能量分析和?分析.研究了R134a,R22,R404a这3种制冷剂在不同蒸发温度和冷凝温度下循环性能系数、总损失、总效率的变化,以及系统中各部件的?损失、?损失占比和?效率.结果表明,在所选工况范围内,R22的性能系数、总?损失、总?效率均优于R134a和R404a,但与R134a相比无显著差异.计算结果表明,系统中压缩机、冷凝器、毛细管是循环总?损失的主要来源,而回热器及蒸发器的损失较少,分析了其原因,并提出了改进建议.更多还原

【Abstract】 The VCRS(vapor compression refrigeration system)was applied as a subcooler to obtain the needed temperature of a cryoablation system by J-T effect,and a mathematic model based on the first and second laws of thermodynamics was established for the energy and exergy analysis using R134 a,R22 and R404 a in the subcooling system of the cryoablation system.The effects of the evaporator and condenser temperatures on the COP,total exergy destruction and total exergy efficiency of the system were investigated.The exergy destruction and exergy efficiency in different system components were also displayed.The R134 a and R404 a systems have lower COPand exergy efficiency but higher exergy destruction compared to the R22 system.However,the performance of R134 a system is closer to the R22 system.So,the best refrigerant is R22 and R134 a is a good alternative to R22.The major exergy destruction occurs in the compressor,condenser and capillary tube among all system components.The reasons and improvement suggestions were presented.更多还原