The expansion device, which may be at the outlet of the condensing unit or at the inlet of the evaporator unit, causes a pressure drop in the liquid refrigerant to enter the evaporator under low pressure and in the process of changing from liquid phase to liquid. gas phase, that is, with the pressure drop the fluid goes from the liquid phase to the gas phase absorbing heat
vaporization latent under constant temperature and pressure, generally from 5 ° to 7 ° C.
After the vaporization process the fluid leaves the evaporator still below room temperature and follows through the suction line absorbing heat, the fluid is said to be
overheating. The overheated fluid is suctioned by the compressor starting the cycle again.
