不同跨临界二氧化碳制冷循环的性能比较

建立了CO2制冷循环各个部件的稳态仿真模型，对6种不同的跨临界CO2制冷循环进行了稳态仿真，衡量了吸气回热、回收膨胀功以及二级压缩等方式对系统性能的影响．结果表明，采用二级压缩并回收膨胀功可以大大提高系统的性能；只采用两级压缩而不回收膨胀功，对系统的性能并没有明显的改善；单级压缩时如果系统中带有膨胀机，采用吸气热交换器可以提高制冷量，但对性能系数(COP)值的影响不大；单级压缩不回收膨胀功时，采用吸气热交换器可以大大提高系统的制冷量和COP。

Performance Comparison of Varied Transcritical Carbon Dioxide Refrigerating Cycle

Steady state simulation models of all refrigerating components were established and applied to six transcritical CO 2 refrigerating cycles. Utilizing these simulation models, the influences of suction superheat, expansion work recovery and two stage compression on the system performance were evaluated. The simulation results show that the two stage compression cycle with expansion work recovering can greatly improve the system performance, while without expansion work recovering it will do nothing good. To the single stage cycle with an expander, a suction line heat exchanger will increase the cooling capacity, but have little effect on COP; while without an expander the cooling capacity and COP both will be increased.