Condenser liquid refrigerant enters the first orifice, which reduces the refrigerant pressure to the suction pressure of the third stage. This pressure drop causes some of the refrigerant to vaporize, and the resulting mixture of liquid and vapor to enter the economizer's high pressure chamber. Then the refrigerant vapor is separated from the mixture and fed to the third stage suction. The remaining liquid goes to the second expansion device.
The second expansion device further reduces the refrigerant pressure to the second stage suction pressure. This pressure drop causes some of the refrigerant to vaporize, and the resulting mixture of liquid and vapor to enter the economizer's low pressure chamber, where the vapor is separated from the mixture and directly into the second stage suction. The remaining liquid proceeds to the third expansion and evaporator device.
Again, the latest expansion device reduces refrigerant pressure and temperature to evaporator conditions.
