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

• A. Increase pressure of refrigerant
• B. Condense refrigerant to liquid
• C. Absorb heat from the environment
• D. Filter impurities

Answer: (D)

The primary function of the refrigerant compressor is to raise the pressure (and thus the temperature) of the refrigerant vapor. After the evaporator, the refrigerant is a low‑pressure, low‑temperature vapor. The compressor adds energy to it, increasing its pressure so it can flow through the system and reject heat in the condenser. This pressure rise is what drives heat transfer to the surroundings, allowing the cycle to continue. Absorbing heat from the environment happens in the evaporator, where the refrigerant absorbs heat and evaporates; condensing to a liquid occurs in the condenser; filtering impurities is not the compressor’s main role.