复叠式与二级压缩式热泵冷冻干燥系统循环特性比较

为了降低干燥过程的能耗,提高冷冻干燥过程的经济性,故以R600a/R290和R90为工质,分别构建了复叠式循环和二级压缩式循环的热泵冷冻干燥系统.对2种热泵干燥系统的构建方法和循环性能进行了分析和计算,并讨论了中间温度、加热温度和冷阱温度变化对系统循环特性的影响.计算结果表明,复叠式热泵循环和二级压缩式热泵循环均可用于冷冻干燥系统;在常规的冷冻干燥条件下,系统中采用复叠式热泵循环较适宜.

COMPARISON ON PERFORMANCES OF CASCADE HEAT PUMP AND TWO-STAGE COMPRESSION HEAT PUMP FOR FREEZE-DRYER

To reduce the energy consumption and improve economic performance of freeze-drying, a cascade system and a two-stage compression heat pump system for freeze-dryers, in which R600a/R290 and R290 served as work fluids respectively, have been investigated. The analyses on the performance of the two systems were conducted through variation of the temperature in the intermediate heat exchanger, heating platen and vapor condenser. The results show that the two systems are both feasible to freeze-dryer. Under the operational conditions in convention, the cascade heat pump system is slightly superior to the two-stage compression system.