In a refrigeration cycle, by vapor compression (refrigerator, air conditioning), there are basically five components:
Compressor, condenser, expansion device, evaporator and refrigerant.
The refrigerant fluid in the form of a saturated liquid passes through the expansion device (restriction), where it is subjected to a sudden pressure drop, where it has two states: predominantly liquid and, to a lesser extent, gaseous. The refrigerant at this point is called flash gas. Then, the fluid is conducted to the evaporator, where it will absorb heat from the air in the environment to be acclimatized, vaporizing itself.
At the evaporator exit, in the form of gas, it is sucked by the compressor, which raises its pressure (and temperature) so that it is conducted through the condenser, where it will give heat to the external environment, condensing the fluid and completing the cycle. The fan forces air circulation, causing the air to be cooled to cross, perpendicularly, the finned tubes of the evaporator coil
