What condition does the refrigerant have when it is at 10 PSIG and -8°F?

When analyzing the state of refrigerant at specific pressure and temperature, it's essential to refer to the saturation characteristics of the refrigerant being used, which in the context of ammonia refrigeration systems is R-717 (ammonia).

At a pressure of 10 PSIG, a corresponding saturation temperature can be identified from the ammonia refrigeration tables. When this saturation temperature is found, it's compared to the actual temperature given in the question, which is -8°F. The saturation temperature at 10 PSIG for ammonia is higher than -8°F.

When the temperature of the refrigerant is lower than the saturation temperature at a given pressure, the refrigerant exists in the saturated state, meaning it is at a temperature that maintains a balance between its vapor and liquid percentages – it can exist as a mix of liquid and vapor.

In contrast, if the refrigerant were superheated, it would need to be at a temperature above saturation temperature for that pressure, which is not the case here since -8°F is well below the saturation temperature for 10 PSIG. The states of subcooled or liquid could misinterpret the presence of liquid phase without the correct context of temperature against the saturation point.

Thus, the refrigerant being at 10 PS