r404a

Some key problems of design of R404A / R23 cascade refrigeration unit

R404A/R23复叠制冷机组设计中的几个关键问题

The refrigeration system consists of two screw compressors utilizing R404A fluid as the refrigerant .

在冷冻单元包括两台螺杆式压缩机，使用R404A作为制冷剂。

The refrigerants of pre-cooling cycle and refrigeration cycle were R404A and R740 .

预冷系统和制冷循环的制冷剂分别为R404A和R740。

The cascade refrigeration unit using R404A / R23 as refrigerant can achieve low temperature , - 80 ℃, and has the advantage of environmental protection .

以R404A和R23为制冷剂的复叠制冷机组，不但满足了制取-80℃的低温要求，还具有环保的优点。

Based on the experimental data collected , the formulations are selected which can predict accurately in-tube condensation heat transfer coefficients for R290 and R404A .

对于R290和R404A，分别根据各自光管、内螺纹管内凝结换热系数的关联式计算数值与实验数据的比较，筛选出了相应预测精度较好的理论模型。