What is the primary function of the compressor in a vapor-compression refrigeration cycle?

• A. To absorb heat
• B. To expand refrigerant
• C. To filter contaminants
• D. To compress low-pressure vapor into high-pressure vapor, driving the cycle

Answer: (D)

In a vapor-compression cycle, the compressor does work on the refrigerant to raise its pressure and temperature, turning the low-pressure vapor that comes from the evaporator into high-pressure, high-temperature vapor. This high-pressure vapor then releases heat in the condenser as it flows through, which is essential for the cycle to continue. After rejecting heat, the refrigerant is expanded and cooled in the expansion device to start absorbing heat again in the evaporator.

Absorbing heat happens in the evaporator, not the compressor. Expansion occurs in the expansion device, not the compressor. Filtering contaminants isn’t the primary role of the compressor—its main job is tocompress and raise the pressure of the refrigerant to drive the cycle.