CO2跨临界制冷循环最优排气压力研究

Study on the optimum exhaust pressure of CO2 transcritical refrigeration cycle

针对国内气候条件提出一种CO2跨临界双级压缩制冷循环,研究其气体冷却器出口温度与压缩机排气压力的变化对COP的影响,发现该循环在气体冷却器出口温度31~41℃工况下的最优COP比单级压缩制冷循环的最优COP高0.316,对应的最优排气压力比单级压缩制冷循环的最优排气压力小0.389 MPa。由此得出两个系统取得最优COP时的排气压力与气体冷却器出口温度经验式,经与前人的结论进行对比分析,本文所得经验式具有较高精度。

In this paper,a CO2 transcritical two-stage compression refrigeration cycle was proposed for domestic climatic conditions,and the influences of the change of outlet temperature of gas cooler and exhaust pressure of compressor on COP in the cycle were studied.It is found that the optimal COP of the two-stage compression refrigeration cycle at the outlet temperature of gas cooler from 31 to 41℃is 0.316 higher than that of the single-stage compression refrigeration cycle.The optimal exhaust pressure of the two-stage compression refrigeration cycle is 0.389 MPa less than that of the stage compression refrigeration cycle.Based on the calculation results,the empirical formulas of the optimal exhaust pressure and the outlet temperature of the gas cooler are summarized when the most COP is obtained by the two systems.By comparing with the conclusions of the predecessors,the empirical formulas proposed in this paper are verified to be higher accuracy.