Final answer:
The compressor in an air conditioning system changes a low-pressure vapor to a high-pressure vapor, contributing to the cooling cycle where it eventually helps in transferring heat out of the room.
Step-by-step explanation:
The role of the compressor in an air conditioning system is to increase both the pressure and temperature of the refrigerant. The compressor specifically changes a low-pressure vapor to a high-pressure vapor. This compressed high-pressure vapor is then forced into the condenser coils, where the temperature being higher than that of the inside room facilitates heat transfer to the room, leading the gas to condense into a liquid. Subsequently, the high-pressure liquid flows through an expansion valve becoming a low-pressure liquid which is further cooled as it moves to the outdoor evaporator coils. Notably, in a cooling cycle, the roles of the evaporator and condenser coils are interchanged, and the direction of the refrigerant flow reverses.