Does the refrigerant change state in the compressor

• A. Yes, it changes from liquid to gas
• B. No, it remains a vapor and is compressed to higher pressure
• C. It changes from solid to liquid
• D. It becomes plasma

Answer: (B)

In the compressor, the refrigerant is a vapor and is compressed to a higher pressure. The compressor’s job is to do work on the low-pressure vapor from the evaporator, raising its pressure (and temperature) so it can flow to the condenser and release heat. Phase changes occur in other parts of the cycle: the evaporator turns liquid into vapor by absorbing heat, and the condenser turns vapor back into liquid by releasing heat. If liquid were to enter the compressor, it can cause damage, but under normal operation the refrigerant enters and leaves as a gas, just at higher pressure.