Where does superheat collide?

In thermodynamics and refrigeration superheat is the number of degrees a vapour sits above its saturation (boiling) temperature at a given pressure, the sensible heat carried once the last liquid has evaporated. In a refrigeration cycle, measured superheat at the evaporator outlet confirms that only vapour, not liquid, reaches the compressor; Stoecker and Jones's Refrigeration and air conditioning and Çengel and Boles's Thermodynamics: An engineering approach both use it this way, and in steam practice the same idea gives superheated steam. The referent is a positive temperature difference above the saturation line for a vapour, routine and controlled, not the precarious metastable state of a liquid.[1][2]

Unit

Degrees of temperature above the saturation point of the vapour

Recovery means

Not applicable

Measured by

Measured as the vapour temperature minus the saturation temperature at the same pressure, read at the evaporator or boiler outlet

In the physics of phase transitions superheating is the metastable condition of a liquid heated above its boiling point that has not yet boiled, because no vapour nucleus has formed, the state that ends in sudden, violent bumping once nucleation finally occurs. Debenedetti's Metastable liquids: Concepts and principles develops the thermodynamics and stability limits of such superheated liquids and the nucleation that releases them. The referent is an unstable, delayed phase change in a liquid, defined by how far past saturation the liquid persists before it flashes, the inverse situation to a vapour's ordinary, stable superheat, and a genuine trap for the shared word.[3]

Unit

The degrees a liquid persists above its boiling point before nucleating

Recovery means

Not applicable

Measured by

Characterised by the attainable superheat, the kinetic spinodal, and the nucleation rate that ends the metastable state