A commercial HVAC system typically consists of four main components: an air handler, a condenser, a compressor, and a thermostat. The air handler is responsible for circulating air throughout the building, while the condenser is responsible for cooling the air. The compressor is responsible for pressurizing the refrigerant, and the thermostat is responsible for controlling the temperature. Additionally, commercial HVAC systems may also include ductwork, dampers, and other components to ensure proper air flow and temperature control.