中文摘要：

对采用R744／R290混合自然工质的自复叠制冷循环的热力性质进行分析。经过计算，得出了冷凝器压力、蒸发器压力、冷凝器出口温度、蒸发器出口制冷剂的状态、混合工质中R744浓度对系统性能的影响。为今后11744／11290的实验研究和实际应用提供了理论依据，减少了实验的工作量。

英文摘要：

The analysis of thermodynamic properties of an auto-cascade refrigeration system using R744/R290 natural mixture is taken. Through calculation, the variations of system properties respect to the pressure of condenser and evaporator, the temperature at condenser outlet, the phase of refrigerant at evaporator outlet and the mole fraction of R744 in R744/ R290 mixtures are presented, which provide theoretic gist for the study and application of R744/R290 mixture and reduce the quantity of experiment.