What is the typical state of refrigerant in the suction line?

What is the typical state of refrigerant in the suction line?

• A. High pressure vapor
• B. Liquid at ambient temperature
• C. Low pressure/ low temperature vapor
• D. High temperature vapor

Answer: (C)

The suction line is the low-pressure side of the system where refrigerant returns to the compressor after absorbing heat in the evaporator. Because the evaporator boils the refrigerant, the returning refrigerant is in the vapor state at a low pressure and relatively low temperature. In practice, there’s often a small amount of superheat, meaning the vapor is slightly warmer than the saturated vapor at that pressure to prevent liquid from entering the compressor. So the typical state is low pressure, low temperature vapor (often with some superheat).

The suction line is the low-pressure side of the system where refrigerant returns to the compressor after absorbing heat in the evaporator. Because the evaporator boils the refrigerant, the returning refrigerant is in the vapor state at a low pressure and relatively low temperature. In practice, there’s often a small amount of superheat, meaning the vapor is slightly warmer than the saturated vapor at that pressure to prevent liquid from entering the compressor. So the typical state is low pressure, low temperature vapor (often with some superheat).