If you say a refrigerant is superheated, what is its phase?

A refrigerant that is described as superheated is in a gaseous phase. Superheating occurs when a refrigerant vapor is heated beyond its saturation temperature at a given pressure, causing it to become entirely gaseous and eliminating the presence of liquid droplets.

This state is essential in refrigeration systems, as it ensures that the refrigerant is in its most efficient form for absorbing heat as it passes through the evaporator coils. By maintaining the refrigerant in a superheated state, the system can prevent the risk of liquid refrigerant entering the compressor, which could cause damage or inefficiency.

The other phases—liquid only, gas and liquid combination, and solid—do not apply to the situation of superheated refrigerant. In the case of a liquid refrigerant, it is at a lower energy state and holds a different set of thermodynamic properties. A gas and liquid combination indicates a saturation state, where the refrigerant is neither purely vapor nor purely liquid, and is not superheated. Finally, solid does not apply in thermal cycles involving refrigerants, as refrigerants typically operate in the gaseous and liquid states within common temperature ranges.