What is the term for the heat added to a vapor after its state change?

The correct term for the heat added to a vapor after its state change is referred to as superheat. When a liquid undergoes a phase change to vapor (for example, during boiling in a refrigeration cycle), it initially absorbs heat at a constant temperature until it fully transitions to the vapor state. After the phase change is complete, any additional heat that is added to this vapor raises its temperature above the boiling point. This additional heat input while the substance remains in the vapor phase is known as superheat.

Sensible heat relates to the heat added or removed from a substance that causes a change in temperature but does not change the state. Latent heat refers to the heat absorbed or released during a phase change at constant temperature, without changing the overall heat content. Enthalpy represents the total heat content of a system but does not specifically indicate the heat added after a phase change occurs.

Understanding superheat is essential in HVAC and refrigeration applications, as it helps to ensure that the vapor is adequately heated above the saturation point to prevent liquid refrigerant from returning to the compressor, which could cause damage.