An Ammonia refrigerant line containing Ammonia at 11" Hg and -20ºF is considered:

The situation described involves an ammonia refrigerant line at a pressure of 11" Hg and a temperature of -20ºF. At these conditions, the state of the ammonia can be analyzed using a pressure-temperature chart specifically for ammonia.

Superheat refers to the condition of a refrigerant that is in a vapor state and has been heated beyond its saturation temperature at a given pressure. In this case, if the ammonia is at a pressure of 11" Hg and a temperature of -20ºF, it suggests that the refrigerant is likely in a vapor state, and we need to determine if it is indeed superheated.

To determine if the ammonia is superheated, you would typically look up the saturation temperature corresponding to 11" Hg in the ammonia saturation table. If the saturation temperature is higher than -20ºF, this indicates that the ammonia vapor is further heated beyond its saturation point, thus categorizing it as superheated.

In conclusion, the ammonia refrigerant line at 11" Hg and -20ºF is indeed in a state of superheat, as the vapor is above the saturation temperature for that pressure, confirming the correct classification as superheated vapor.