What is superheat in a refrigeration cycle?

Superheat in a refrigeration cycle refers to the temperature of the refrigerant vapor above its boiling point. After the refrigerant has absorbed heat and transformed from a liquid to a vapor phase, it continues to gain additional heat, which raises its temperature above the boiling point specific to that refrigerant at a given pressure. This additional temperature increases the efficiency of the refrigeration system, as it ensures that the refrigerant is entirely in vapor form before it reaches the compressor.

In refrigeration systems, maintaining an adequate level of superheat is important to prevent liquid refrigerant from entering the compressor, which could cause damage. This is crucial not only for the operational efficiency of the system but also for the longevity of its components. Therefore, understanding superheat is essential for effective temperature control and ensuring the reliability of the refrigeration cycle.

The other options do not accurately describe superheat: the boiling point refers to the phase change point, temperatures below relate to subcooling or conditions prior to phase change, and liquid temperature before evaporation does not consider the context of vapor and superheating.