What is the official definition of saturation in the context of refrigerants?

The official definition of saturation in the context of refrigerants refers to the state where liquid and vapor coexist at the same temperature and pressure. In this state, any additional heat added to the liquid refrigerant will not cause a change in temperature but instead will result in vaporization, while any heat removed from the vapor will not reduce its temperature but will instead lead to condensation into a liquid. This concept is fundamental in various refrigeration cycles and is crucial for understanding how refrigerants behave under different conditions.

In contrast, having only vapor or only liquid present would mean that the refrigerant is either completely vaporized or fully condensed, and there is no equilibrium state between the phases. The presence of both liquid and vapor is what characterizes saturation, making this the correct understanding of the term in the context of refrigerants.