What is the difference between the temperature of the refrigerant boiling in the evaporator and the evaporator outlet temperature called?

The difference between the temperature of the refrigerant boiling in the evaporator and the evaporator outlet temperature is referred to as evaporator superheat. This concept is critical in refrigeration systems because it indicates how much the refrigerant vapor has been warmed beyond its boiling point after it has fully evaporated.

When refrigerant enters the evaporator, it begins to absorb heat from the surrounding environment, causing it to change from liquid to vapor. The boiling point of the refrigerant corresponds to the specific pressure in the evaporator. Once the refrigerant fully evaporates, any additional heat absorbed will increase the temperature of the vapor, which is reflected in the outlet temperature. The difference between these two temperatures—boiling point and outlet temperature—is the superheat.

Superheating is essential for system efficiency and preventing liquid refrigerant from returning to the compressor. If the refrigerant were to still be in liquid form when it reaches the compressor, it could cause damage. Therefore, maintaining an appropriate level of superheat is crucial for the optimal operation of refrigeration systems.

Understanding this distinction helps technicians monitor and control the performance of refrigeration systems effectively, ensuring they operate within designed parameters for efficiency and reliability.