What is the difference between the internal and external circulation of a vehicle's air conditioning system?
4 Answers
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.
After driving for a while, I realized there's quite a difference between the recirculation mode and fresh air mode. Recirculation mode just circulates the air inside the car without letting outside air in, which makes the AC cool or heat faster. Especially during scorching summer days when it feels like a steamer inside, turning on recirculation can cool the car down in seconds while saving fuel. It also blocks exhaust fumes or dust from outside, preventing you from breathing in too much polluted air. Fresh air mode does the opposite - it draws in fresh air from outside, preventing stuffiness and headaches during long drives, though cooling takes slightly longer. In winter, it's more prone to causing fogging. My habit is to switch to recirculation during traffic jams or at red lights, and use fresh air mode on highways for ventilation. Alternating between modes during long trips maintains comfort. Don't forget to regularly clean the AC filter to prevent odors.
I pay great attention to health details and need to understand the differences when using air conditioning. The recirculation mode only circulates the existing air inside the car, providing better temperature control and saving power. However, if used for too long, the air becomes stale with low oxygen levels, which can cause drowsiness and discomfort, especially with many passengers. The fresh air mode introduces outside air, maintaining high oxygen levels to improve concentration and reducing humidity inside the car to prevent mold, but it should be used less in dusty or polluted areas. Using fresh air mode on rainy days helps defog windows quickly for safety, while switching to recirculation is better in smoky conditions. It's recommended to manually switch between modes every half hour or during long drives to maintain health.
When I first started using the car, I couldn't figure out the air conditioning buttons. The recirculation mode means the fan blows air inside the car, cooling or heating it quickly, but it can get stuffy without ventilation. The fresh air mode draws in outside air, making it fresher but slower to adjust the temperature. The specific differences are: recirculation is suitable for short trips or traffic jams to prevent inhaling exhaust fumes; fresh air mode is better for long drives or after rain to avoid motion sickness and foggy windows. I found that the auto mode switches automatically, but manual operation is more practical—using recirculation in high temperatures and switching to fresh air on rainy days. Simply remember: use recirculation for efficiency and fresh air for comfort.
