In the vapor compression refrigeration cycle, which state does the refrigerant take when heated above its saturation temperature?

• A. It condenses into a liquid
• B. It remains in the vapor state
• C. It becomes a solid
• D. It evaporates further

Answer: (B)

When the refrigerant is heated above its saturation temperature in the vapor compression refrigeration cycle, it continues to exist in the vapor state. This is because saturation temperature is the temperature at which a substance transitions between phases—specifically from vapor to liquid or vice versa. When the refrigerant is heated beyond this temperature while remaining in a vapor state, it is referred to as superheated vapor.

Superheating increases the energy of the refrigerant in the vapor phase and is an important part of the refrigeration cycle as it ensures that the refrigerant remains in the vapor form when it reaches the compressor. This is crucial for efficient operation, as compressing liquid refrigerant is ineffective and can cause damage to the system.

The other options describe scenarios that do not occur when the refrigerant is heated above its saturation temperature. The refrigerant will not condense into a liquid or become a solid, and it will not evaporate further since it is already in the vapor phase. The focus on superheating ensures that the system operates correctly and effectively during its cycle.