变频滚动转子式压缩制冷系统的分析

The exergy analysis of variable frequency rolling rotor compression refrigeration system

针对吸气带液状态下变频压缩机组分析对优化热力系统的运行有着很明确的指导价值,研究和分析了不同吸气状态和不同压缩机频率下损失、效率、损率、损系数、制冷量、制冷系数(COP)、总损失、总效率以及总损系数的变化趋势,并比较得出了吸气带液时哪个设备是系统最薄弱环节。结果表明:1当压缩机少量吸气带液时,冷凝器和蒸发器效率的提升大于压缩机效率的下降,也就是说少量吸气带液对蒸发器和冷凝器的有利影响大于对压缩机的不利影响;2系统的总损失和总损系数在x=0.95左右达到最小,而总效率在x=0.95左右达到峰值;3当压缩机在较高频率下工作时,冷凝器和蒸发器的损失将会明显增加;4当压缩机频率为50Hz且吸气带液时,蒸发器的损失、损率和损系数最大,效率最小,此时蒸发器为系统最薄弱环节。指出以上结论也适用于同型号的滚动转子式压缩机。

Since the exergy analysis of variable frequency compressors has clear guidance values about optimizing the thermodynamic system operation under liquid-vapor mixture refrigerant suction,the changing trends of the exergy loss,exergy efficiency,exergy loss rate,exergy loss coefficient,refrigerating capacity,COP,total exergy loss,total exergy efficiency and total exergy loss coefficient under different suction states and compressor efficiencies have been analyzed and which equipment is the weakest link in the system under liquid-vapor mixture refrigerant suction has also been obtained. Results showed that：1when rolling rotor compressors suck vapor refrigerant mixed a little liquid refrigerant,the increase of exergy efficiency of condenser and evaporator is greater than the decrease of exergy efficiency of compressor;that is to say,the beneficial effects of liquid-vapor mixture refrigerant suction on condensers and evaporators are greater than the adverse impacts on compressors. 2The total exergy loss and total exergy loss coefficient are minimum at x=0.95,while the total exergy efficiency is maximun at x=0.95. 3When compressors are operated under high efficiencies,the exergy losses of condenser and evaporator will be increased significantly. 4When the compressor efficiency is 50 Hz and compressor sucks vapor refrigerant mixed a little liquid refrigerant,the exergy loss,exergy loss rate and exergy loss coefficient of evaporator are maximun and the exergy efficiency of evaporator is minimum. Thus,the evaporator is the weakest link in the system at this moment. The conclusions mentioned above are the same with the same type of rolling rotor compressors.