跨临界CO2制冷循环性能的研究

文中对理想的跨临界ＣＯ２制冷循环，进行了理论分析和性能计算，揭示了该循环的一些特点：对于一定的冷却器出口温度，对应一个使系统性能系数最佳的冷却压力，而且系统性能系数最佳时的冷却器出口温度与冷却压力的对应关系，可以用一个简单的代数式表示；提高蒸发温度可显著提高循环的性能系数；当冷却压力较低时，提高循环的吸气过热度，可显著地提高系统的性能系数；冷却器出口温度越高，效果越明显，当蒸发温度和冷却器出口温度较高时，减小回热器传热温差，可有效地提高系统的单位容积制冷量和性能系数．这些结论，对于跨临界ＣＯ２制冷系统的运行操作具有重要的指导作用．

Performance of Super Critical CO_2 Refrigeration Cycle

The ideal super critical refrigeration cycle of CO 2 is analyzed. For a given outlet temperature of the cooler, there exists an optimum cooling pressure that maximizes the coefficient of performance(COP). When the COP reaches a maximum, the correlation between the cooler outlet temperature and cooling pressure can be expressed by a simple formula. The system COP can be improved by the raising evaporation temperature or enhancing the suction superheat degree for low cooling pressure and elevating the cooler outlet temperature. When the evaporator and cooler outlet temperatures are high, a decrease in the heat transfer temperature difference of the regenerator can improve the specific cooling capacity and COP. The results can be used to guide the design and operation of super critical CO 2 refrigeration system.