Car Air Conditioning: External Circulation or Internal Circulation?

[DeEverett]

Generally, internal circulation is more commonly used when running the air conditioning in a car. Below are detailed explanations of internal and external circulation in car air conditioning: 1. External Circulation: External circulation refers to drawing air from outside the car, directing it into the air conditioning system for heating or cooling, and then blowing it out through the vents. Essentially, external circulation replenishes fresh air, improving the air quality inside the car. It is used for defrosting in winter or defogging in summer because the air drawn from outside is richer in oxygen and drier, making it more effective for defrosting or defogging. 2. Internal Circulation: Internal circulation draws air from inside the car, creating a cycle of airflow within the vehicle. Its main function is to promptly and effectively block external dust and harmful gases from entering the car. It heats up the car faster in winter and cools it down more quickly when the air conditioning is on in summer. It can also be used during smoggy days. Internal circulation cycles the air inside the car, helping to maintain the interior temperature more effectively.