What state is the ammonia in a refrigerant line at 80°F and 120 psi G?

In the context of refrigerant properties, the state of ammonia at 80°F and 120 psi G (gauge pressure) can be determined by examining the phase diagram of ammonia. At these specific conditions, ammonia is found to be in the vapor state.

For ammonia, the saturation pressure at 80°F is approximately 120 psi. This means that at 80°F, ammonia can exist as either a liquid or a vapor depending on the pressure. However, since the provided pressure is gauge pressure, which does not account for atmospheric pressure, it’s important to consider the absolute pressure for the refrigerant’s state. Once atmospheric pressure is added, the absolute pressure is roughly 135 psi.

At 80°F, an absolute pressure of 135 psi lies above the saturation pressure, indicating that the ammonia would be in a superheated state—essentially as a vapor. Thus, at 80°F and 120 psi G, the ammonia in the refrigerant line is primarily in the vapor phase, confirming that the correct choice is vapor.

This understanding is crucial in refrigeration systems, as the state of the refrigerant affects thermal and pressure dynamics for efficient cooling.