Which One is the External Circulation?

[MacFelicity]

External circulation is a switch with an arrow pointing from outside the car to the inside. Working principle of external circulation: It involves the cycle of expelling and drawing in air from inside and outside the car. Simply put, external circulation draws in outside air, cools it through the air conditioning system, and then delivers it into the car. Function of external circulation: It keeps the air inside the car fresh while cooling. Another function is that outside air is usually drier, so using external circulation can better help with defrosting and defogging the windows. Disadvantages of external circulation: The cooling and heating effects of the air conditioning are slightly weaker because external cold or hot air enters the car.