What are the main components of a basic automotive HVAC system?

• A. Compressor, condenser, evaporator, and expansion device
• B. Brake caliper, rotor, master cylinder, and ABS module
• C. Radiator, water pump, thermostat, and heater core
• D. Alternator, battery, starter, and fuse box

Answer: (A)

Air conditioning in a car runs on a closed refrigerant cycle, with four main components driving the cooling effect: the compressor, condenser, expansion device, and evaporator. The compressor pumps refrigerant as a high‑pressure gas into the condenser, where it releases heat to outside air and becomes a high‑pressure liquid. The expansion device then lowers the refrigerant’s pressure, causing it to cool rapidly. In the evaporator, the low‑pressure refrigerant absorbs heat from the cabin air as it boils back into a gas, cooling the air that blows over the evaporator core. Additional parts like a receiver/drier help remove moisture and contaminants, and the blower and blend doors control air flow and temperature inside the cabin. The other options describe braking components, engine cooling parts, and electrical charging items, which aren’t part of the basic HVAC cycle.