R290/R1233zd(E)在变温热源喷射制冷循环中的性能优化研究
Performance optimization study on R290/R1233zd(E) in a variable temperature heat source ejector refrigeration cycle
摘要：
提出了一种优化喷射制冷系统的新型策略,建立了非共沸混合制冷剂R290/R1233zd(E)在变温热源下的热力学模型。通过数值模拟,分析了R290/R1233zd(E)的温度滑移和换热器冷热源温度变化对换热器和喷射制冷系统性能的影响。结果表明:相对于单一工质,混合工质可以提高工作流体和引射流体的进口温度、优化系统性能,R290/R1233zd(E)(质量分数分别为0.7、0.3)为该系统最佳混合工质,相较于单一工质R1233zd(E),系统性能系数提高了44%、系统㶲效率提高了39%。R290/R1233zd(E)的最佳质量分数随冷凝器中冷却水出口温度的升高而增大,随冷凝器中冷却水进口温度的升高而减小。由于夹点位置的影响,对于不同温度滑移的混合工质而言,发生器㶲损失与冷凝器㶲损失的大小关系不同,喷射器㶲损失和发生器㶲损失随温度滑移的增大先增大后减小,冷凝器㶲损失随温度滑移的增大先减小后增大。
Abstract：
In this paper, a new strategy for optimizing the ejector refrigeration system is proposed, and a thermodynamic model with the non-azeotropic mixed refrigerant R290/R1233zd(E) under variable temperature heat source is established. The influences of the temperature slip of R290/R1233zd(E) and the temperature change of cold and heat source of the heat exchanger on the performance of the heat exchanger and ejector refrigeration system are analysed by numerical simulation. The results show that compared with the single working fluid, the mixed working fluid can increase the inlet temperature of working fluid and injection fluid, optimize system performance, and R290/R1233zd(E) (mass fractions of 0.7 and 0.3, respectively) is the optimal mixed working fluid for this system. Compared with the single working fluid R1233zd(E), the coefficient of performance of the mixed working fluid system increases by 44% and the system exergy efficiency increases by 39%. The optimal mass fraction of R290/R1233zd(E) increases with the increase of the cooling water outlet temperature in the condenser, and decreases with the increase of the cooling water inlet temperature in the condenser. Due to the influence of the pinch point position, the relationship between the generator exergy loss and the condenser exergy loss is different for mixed working fluids with different temperature slips. The injector exergy loss and generator exergy loss first increase and then decrease with the increase of temperature slip, while the condenser exergy loss first decreases and then increases with the increase of temperature slip.
Keywords:R290/R1233zd(E); mixed refrigerant; temperature slip; heat exchanger; performance optimization; variable temperature heat source; exergy loss; ejector refrigeration cycle