This trainer allows the student to experiment with and control a Cascade (Multistage) Compressor Application.  Cascade systems are typically used where ultra low temperatures are desired but cannot be economically obtained through the use of a single stage system.  This is because the compression ratios would be too high to get the necessary evaporating and condensing vapor temperatures.  In industrial applications cryogenic temperatures can even be achieved with this type of system. 

In the Cascade Refrigeration System Trainer, two separate refrigeration systems are interconnected in series (cascade) so that the evaporator from one unit is used to cool the condenser of the other unit.  This arrangement allows one of the units to operate at a lower temperature and pressure than would be possible with the same size single-stage system.  This system is actually two independent units and it allows theoretically the use of two different refrigerants.  The High Stage system cools the refrigerant for the Low Stage.