跨临界CO_2蒸气压缩/喷射制冷循环分析

Thermodynamic Analysis of a Transcritical CO_2 Vapor Compression/Ejection Refrigeration Cycle

利用喷射器代替节流阀作为CO_2制冷循环的主要膨胀装置,回收膨胀过程的部分动能,减少节流损失,降低压缩机耗功,并通过在压缩机进气前开一旁路,调节压缩机进气量,使系统稳定。对喷射循环与节流阀循环、膨胀机循环进行了性能比较,得出了喷射器循环相对于其他两种循环的优势;并对系统中各个参数对系统性能的影响进行了分析,系统蒸发和冷却温度对CfP影响较大;最后对系统(?)分析得到蒸发器到喷嘴后的压力差对COP和(?)损失的影响较大。

In this paper,the ejector is used instead of the throttle valve as the main expansion device in the CO_2 refrigeration cycle,in order to recover kinetic energy in expansion process to reduce power consumption of the compressor and energy loss of the throttle valve.A by-pass is setted before the compressor inlet,to adjust the mass of gas into the compressor,making the system stable.It compares the performance of ejector cycle with the throttle valve cycle and the expander cycle.The influence of the system parameters is also studied,and the main factor are the evaporation temperature and cooling.Finally,the system exergy is analysed and the pressure difference between evaporator and nozzle outlet have a great influence.