Chill Out with the 2025 QMED Basic Refrigeration Exam – Freeze the Competition!

To calculate superheat accurately, the relationship that defines it is the difference between the actual vapor temperature and the saturation temperature at the corresponding pressure. Superheat is a measure of how much the temperature of the vapor exceeds the saturation temperature of the refrigerant at the same pressure.

When a refrigerant is in its vapor state, it can be superheated by adding heat beyond its boiling point (saturation temperature). This is crucial in refrigeration systems, as superheating ensures that the refrigerant vapor does not condense within the evaporator coils, which could cause damage and reduce the system's efficiency.

In practical terms, if you measure the actual temperature of the vapor and subtract the saturation temperature at the observed pressure, you obtain the superheat value. This value indicates how much additional heat is present in the refrigerant vapor after it has completely vaporized.