What is the superheat at the inlet of the compressor if the suction pressure is 32 PSIG and the suction temperature is 24ºF?

To determine the superheat at the inlet of the compressor, it's important to understand the relationship between the refrigerant's pressure, temperature, and its phase states. Superheat is the temperature of a vapor above its saturation temperature at a given pressure.

In this scenario, the refrigerant is at a suction pressure of 32 PSIG. First, we need to convert this pressure to absolute pressure, which is necessary for finding the saturation temperature. To do that, we add atmospheric pressure (14.7 PSIA) to the gauge pressure (32 PSIG), resulting in a total of 46.7 PSIA.

Next, by referring to a refrigerant pressure-temperature chart or tables for the specific refrigerant being used, we can find the saturation temperature corresponding to 46.7 PSIA. For many common refrigerants, this would be around 19ºF (this value can vary depending on the refrigerant type).

Given that the suction temperature is 24ºF, we can now calculate the superheat. Superheat is calculated as the difference between the actual suction temperature and the saturation temperature:

Superheat = Suction Temperature - Saturation Temperature

Assuming the saturation temperature we found is approximately 19ºF, we can