What is the difference between the internal and external circulation of a vehicle's air conditioning system?

[OAurora]

The main differences between the internal and external circulation of a vehicle's air conditioning system lie in their definitions and functions. 1. Internal circulation in a car: Refers to the process where air inside the vehicle is heated or cooled and then recirculated back into the cabin. External circulation: Involves drawing air from outside the vehicle, heating or cooling it, and then supplying it into the cabin, effectively exchanging air between the interior and exterior. 2. External circulation in a car: Uses a fan to draw outside air into the vehicle, meaning there's airflow between the exterior and interior air ducts. The air blown by the fan comes from outside, and even when the fan is off, moving air is still drawn into the cabin while driving, replenishing fresh air inside.