中文摘要：

运用热力学第一定律和第二定律对跨临界CO2基本循环、膨胀机循环、喷射器循环和涡流管循环进行了分析，计算了各循环各个部件的炯损失，比较了各循环性能系数和总炯损失。计算结果表明，采用膨胀机、喷射器和涡流管等膨胀设备代替基本循环中的节流阀后，由于这些改进膨胀设备的炯损失小于基本循环节流阀的炯损失，同时改进循环中压缩机的炯损失小于基本循环的压缩机炯损失，从而减小了循环总炯损失，提高了循环的COP。膨胀机循环的COP远大于其它跨临界CO2循环，其次为喷射器循环和涡流管循环。

英文摘要：

A comparative study on transcritical carbon dioxide refrigeration cycle respectively with throt- tling valve, expander, ejector and vortex tube was performed by the first and second laws of thermodynamics in theory. And these cycles＇ COP and exergy losses were investigated. It is found that the exergy loss of oth- er expansion devices is less than the exergy loss of throttling valve. The exergy loss of compressor in tran- scritical carbon dioxide refrigeration cycle with other expansion devices is less than the exergy loss of com- pressor in transcritical carbon dioxide refrigeration cycle with throttling valve. Thus the total exergy loss of these cycles with other expansion devices is less than the total exergy loss of cycle with throttling valve, and the COP of these cycles with other expansion devices is higher than the COP of cycle with throttling valve. The COP of transcritical carbon dioxide refrigeration cycle with expander is much higher than that of other cycles, then transcritical carbon dioxide refrigeration cycle with ejector and with vortex tube.