Hi
The refrigerant before entering the evaporator should be subcooled liquid or saturated liquid?
Both.
Once pressurized by the compressor, the saturated liquid becomes subcooled as it leaves the compressor discharge and enters the liquid line.
When it leaves the compressor is it not an extremely superheated vapour? Up until it's done saturating into a 100% liquid by the condenser and then is subcooled additionally before entering the metering device of the evaporator?
Since we can't compress liquids, it has to be vapour going in and coming out.
Yes, I believe the refrigerant leaves the condenser as sub-cooled liquid. As it enters the metering device, the high pressure liquid changes to a low pressure, low temperature, saturated liquid/vapor.
I'm guessing the answer would be the refrigerant is saturated liquid before entering the evaporator.