Page 8 - IOM / TELECOOL THN - 0104 - E
INSTALLATION
Evacuation and charging operations for THN-type units
This type of work must be carried out by qualified personnel only trained to do their job in
accordance with 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
Ö
pressure drop in tank
- pressure drop in tank
Ö
T drop change of state
- T drop change of state
Ö
evaporation of part of the liquid, causing the liquid itself to
cool
- cooling of liquid
Ö
thermal exchange with ambient air, further evaporation of
remaining liquid; the original pressure is restored in the tank
after a certain amount of time
Fig. 1
T tank/ambient
Saturated gas
Saturated liquid
