Liquid refrigerant charging of a system is normally accomplished in the liquid line. For example, when a system is out of refrigerant, liquid refrigerant can be charged into the king valve on the...
Refrigeration works by cooling items to a point too low for certain bacteria to thrive.
Oil in a AC compressor is there so that the mechanical parts don't over heat from friction
To absorb the heat from the refrigerated area using latent heat of evaporation.
at the metering device before the evaporator