并联双循环风冷冰箱短周期切换控制特性

Dynamic characteristic of the air-cooled refrigerator with two parallel-evaporators in the control of short-cycle switching

针对并联双循环风冷冰箱冷藏室、冷冻室不能同步降温,导致冷冻室回温时间长的问题,实验研究了开机后冷藏降温过程中兼顾冷冻降温的"2 min冷藏+1 min冷冻"短周期切换控制特性.结果表明:开机后,停机时积聚在冷冻蒸发器中的制冷剂逐渐向冷藏蒸发器迁移,前6个短周期内,迁移造成的冷藏蒸发器制冷量损失由33.9%降至5.2%,之后维持不变直至冷藏运行结束.冷冻室感温包温度前6个短周期内从-16.5℃降至-17.8℃,而之后5个短周期仅降低约0.3℃.采用短周期切换控制,冷藏降温阶段可兼顾冷冻室降温,且在冷冻降温时间的缩短与冷藏运行时间的延长之间存在使压缩机运行时间最短的最优值.

For the two-circuit refrigerator with parallel evaporators,refrigerating cabinet and freezing cabinet could not get cooling capacity at the same time. This will lead to the increase in compressor-on time due to the fact that the compressor shuts down as the counterpart cut-out temperature in the freezing cabinet is reached. The dynamic characteristics of a parallel-evaporators refrigerator with short-cycle switching control were studied experimentally.Results showed that the refrigerant stored in the freezing-evaporator was immigrated gradually to refrigeratingevaporator due to pumping action of compressor after a startup. The capacity loss of the refrigerating evaporator due to the refrigerant migration decreased from 33. 9% to 5. 2%. In addition,the temperature of the freezer-sensor decreased from-16.5 ℃ to-17.8 ℃ in the first six short-cycles,but only decreased by about 0.3 ℃ in the next five short-cycles. The short-cycle switching control strategy can decrease the temperature in both refrigerating cabinet and freezing cabinet. However,the refrigerating-run time will be extended at the same time. These two factors should be comprehensive considered to make the compressor-on time shortest.