If the line temperature is 70°F and the pressure corresponds to a saturated suction temperature of 42°F, what is the system's superheat?

If the line temperature is 70°F and the pressure corresponds to a saturated suction temperature of 42°F, what is the system's superheat?

• A. 0°F
• B. 12°F
• C. 28°F
• D. 42°F

Answer: (C)

Superheat is the amount by which the actual suction gas temperature exceeds its saturated temperature at the same pressure. Here, the suction line is 70°F and the saturated suction temperature at that pressure is 42°F. Subtracting gives 70 − 42 = 28°F. So the system’s superheat is 28°F. If the line temperature were equal to 42°F, the superheat would be zero; a line temperature of 54°F would be 12°F of superheat; and a line temperature of 42°F would also indicate zero superheat.

Superheat is the amount by which the actual suction gas temperature exceeds its saturated temperature at the same pressure. Here, the suction line is 70°F and the saturated suction temperature at that pressure is 42°F. Subtracting gives 70 − 42 = 28°F. So the system’s superheat is 28°F. If the line temperature were equal to 42°F, the superheat would be zero; a line temperature of 54°F would be 12°F of superheat; and a line temperature of 42°F would also indicate zero superheat.