What does "evaporator superheat" indicate about the refrigerant?

Evaporator superheat is an important concept in refrigeration that describes the temperature of the refrigerant vapor as it exits the evaporator coil, measured above its saturation temperature at a given pressure. When refrigerant enters the evaporator, it absorbs heat and begins to change state from liquid to vapor. Superheat refers to any temperature increase of the vapor beyond the point where it has completely vaporized at the corresponding pressure, indicating that all liquid refrigerant has evaporated and there is no liquid left mixed with the vapor.

A higher superheat means that the refrigerant has absorbed more heat and is fully in its vapor form, which is an essential condition for ensuring efficient operation of the system. Maintaining the proper superheat is critical because it prevents liquid refrigerant from entering the compressor, which could cause damage.

This is why the option indicating evaporator superheat as the measure of the degree of vaporization beyond saturation is the correct answer. It captures the essence of superheat — that it quantifies how much the refrigerant vapor's temperature exceeds its saturation temperature after all liquid has evaporated.