A system running on a type 2 refrigerant such as R134a exhibits a superheat horn on the pressure enthalpy diagram but a system running on a type 3 refrigerant has not superheat horn because the shape of the saturated vapour curve is such that when you start compression with a saturated vapour the exist of the compression lies in the two phase region.

My question is what effect does in the real world?

Is it just that with type 3 refrigerants if there is no suction superheat then there is no discharge superheat?
And with type 2 refrigerants that even with no suction superheat that there will be discharge superheat?


Jon