Which condition in refrigeration indicates that the refrigerant is completely vaporized but at the saturated temperature?

The condition in refrigeration where the refrigerant is completely vaporized but at the saturated temperature is referred to as saturated. In this state, the refrigerant is at the point where it can coexist as both liquid and vapor, meaning it has reached its boiling point at the current pressure. This is important to recognize because when the refrigerant is saturated, any additional heat added will lead to vaporization (if it's liquid) or an increase in temperature (if it's vapor) without a phase change.

In contrast, when a refrigerant is in a superheated state, it is entirely vaporized and exists at a temperature higher than the saturated temperature for that pressure, which does not describe the answer as it implies a condition beyond saturation. Sub-cooled refers to a liquid refrigerant that has been cooled below its saturation temperature, indicating it has not vaporized completely. The trans-critical condition pertains to gases operating above their critical pressure, where the refrigerant behavior changes significantly.

Therefore, the saturated condition is distinct in that it captures the exact transition point for refrigerants at their boiling point, marking an important aspect of understanding refrigeration cycles.