Refrigeration Cycle - Carrier 19DV Series Installation, Operation And Maintenance Instructions

1. Bearing support housing
2. Volute
3. Bearing housing
4. Spacer / sizer
5. Motor shaft laby
6. Motor housing
7. Roller element bearing assembly
8. Impeller labyrinth
9. Bearing flange
10. Impeller shim
11. Shroud
12. Eye laby
13. IGV
14. Nose piece
15. Impeller
Figure 3 – Typical 02DV compressor internal view

2.5.4 - Refrigeration cycle

The compressor continuously draws refrigerant vapor from the evaporator at a rate set by the amount of first stage
guide vane opening and motor speed. As the compressor suction reduces the pressure in the evaporator, the
remaining refrigerant boils at a fairly low temperature (typically 3 to 6°C). The energy required for boiling is
obtained from the water flowing through the evaporator tubes. With heat energy removed, the water becomes cold
enough to use in an air-conditioning circuit or process liquid cooling.
After taking heat from the water, the refrigerant vapor is compressed by a back-to-back compression connected by
means of interstage piping. Compression adds heat energy and the refrigerant is quite warm (typically 37 to 40°C)
when it is discharged from the compressor into the condenser. Relatively cool (typically18 to 32°C) water flowing
into the condenser tubes removes heat from the refrigerant, and the vapor condenses to liquid. The liquid drains
into a high side float valve chamber between the condenser and the economizer. The refrigerant is then metered
into the economizer.
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