RG66001652_REV.02
19
LCW - LCR
.
Evacuation and charging operations for LCR-type units
This type of work must be carried out by qualified personnel trained to do their job
in observance of current laws and regulations
1. Introduction:
The simultaneous presence of liquid and vapour makes it necessary for both to be in a state of saturation [ Gibbs
law ], as shown in fig. 1). In conditions of thermal equilibrium, the pressure in the tank corresponds to the T of the
surrounding environment; a withdrawal of refrigerant charge will cause pressure drops, which will be associated
with
- withdrawal of refrigerant charge
pressure drop in tank
- pressure drop in tank
T drop - change of state
- T drop - change of state
evaporation of part of the liquid, causing the liquid itself to
cool
- cooling of liquid
thermal exchange with ambient air, further evaporation of
remaining liquid; the original pressure is restored in the tank
after a certain amount of time
P
Heat content h
Tank/ambient T
Saturated
Gas
Saturated
liquid
Fig. 1
