What is the superheat of the compressor inlet given a suction pressure of 33 PSIG and a suction temperature of 34°F?

To determine the superheat at the compressor inlet, it’s important to first understand the concept of superheat in refrigeration and air conditioning systems. Superheat refers to the temperature of the refrigerant vapor exceeding its saturation temperature at a given pressure.

In this scenario, you have a suction pressure of 33 PSIG. To find the corresponding saturation temperature, you can refer to a pressure-temperature chart for the specific refrigerant in use. After looking up 33 PSIG (which converts to approximately 48 PSIA, since 14.7 PSIA is atmospheric pressure), you can find the saturation temperature.

Assuming the saturated temperature for 33 PSIG is around 20°F, you can then calculate superheat using the formula:

Superheat = Actual Suction Temperature - Saturation Temperature

Given the actual suction temperature is 34°F, you would have:

Superheat = 34°F - 20°F = 14°F

This calculation confirms that the superheat at the compressor inlet is indeed 14°F, making this choice correct. Understanding superheat is crucial for evaluating system performance, ensuring the refrigerant is vapor at the compressor inlet, and preventing liquid carryover that could damage the compressor.