The difference between the suction gas temperature and the saturated suction temperature is called

• A. Condensing temperature
• B. Superheat
• C. Evaporator operating temperature
• D. Subcooling

Answer: (B)

Superheat describes how much the suction gas temperature exceeds the saturated suction temperature at the evaporator pressure. In a vapor-compression cycle, the refrigerant should leave the evaporator as vapor, and the difference between the actual suction gas temperature and the saturation temperature for that pressure is the superheat. This ensures the compressor draws in gas rather than liquid, protecting it from liquid slugging and helping balance performance.

Other terms don’t describe this specific differential: condensing temperature relates to the condenser side, subcooling refers to how much the liquid is cooled below its saturated liquid point after leaving the condenser, and evaporator operating temperature is simply a temperature of the evaporator itself, not the difference between actual suction gas and its saturation temperature.