二次冷媒无霜电冰箱的理论分析

Theoretical Analysis of Frost-Free Refrigerator-Freezer with Secondary Cooling Medium

为了降低无霜冰箱采用可燃性制冷剂燃烧爆炸的危险性,提出了"二次冷媒无霜电冰箱".对于该型式的电冰箱,箱内空气只与二次冷媒进行热交换,与可燃性制冷剂不直接接触,因此,大大降低了电冰箱采用可燃性制冷剂燃烧爆炸的危险性.同时,二次冷媒电冰箱可以很容易地采用大滑移温差的非共沸制冷制,大大提高了系统的制冷系数(COP).对二次冷媒冰箱采用R32/R600a(0.35∶0.65)、R22/R123(0.45∶0.55)、R32/R600(0.40∶0.60)、R170/R600a(0.08∶0.92)、R32/R245fa(0.40∶0.60)、R290/R123(0.40∶0.60)等混合工质(上述混合工质均为质量比)的理论循环计算表明,其COP比传统无霜冰箱采用R134a的COP提高10%以上.

A kind of refrigerator-freezer (RF) termed frost-free refrigerator-freezer with secondary cooling medium was presented. For this kind of RF, the compartment air only has direct heat exchange with the secondary cooling medium, and does not contact with the refrigerant, so the risk of inflammation and explosion is reduced to the least. At the same time, the non-azeotropic refrigerants are easy used in the RF with secondary cooling medium, so the COP can be increased greatly for the frost-free RF with secondary cooling medium. The cycle performances of frost-free RF with secondary cooling medium are calculated when it is charged with non-azeotropic refrigerants with large gliding temperature. The calculation results show that the COPs are very high when the refrigerants R32/R600a(0.35:0.65), R22/R123 (0.45:0.55), R32/R600(0.40=0.60), R170/R600a (0.08=0.92), R32/R245fa(0.40:0.60), R290/R123(0.40:0.60) are used in the frost-free RF with secondary cooling medium. The COPs increase by a factor of 1/10 compared with the conventional frost-free RF charged with Rl34a refrigerant.