Many modern drivers do not even know about the purpose of this button. We will tell you how the air recirculation system in the passenger compartment is arranged and why, when it is turned on, the windows sometimes fog up sharply.
Climatic installations of machines have a recirculation mode. When this mode is enabled, the damper blocks the air flow from the street. At the same time, due to the operation of the fan in the cabin, a circular movement of air is created.
Previously, special rods or cable-operated sliders were used to control the position of the damper. On modern cars, most functions are controlled by an electric drive, respectively, and recirculation is turned on by pressing a button.
Scheme of air movement in the heating, ventilation and air conditioning system
1 – heater radiator; 2 – damper of the temperature controller; 3 – air conditioner evaporator; 4 – cabin filter; 5 – damper of the air recirculation system; 6 – electric fan.
On modern cars, regardless of the complexity of the recirculation device, the principle of operation and the rules for using this function are the same everywhere.
Why do windows instantly fog up when recirculation is turned on?
Most often this happens in rainy cold weather, when the temperature difference between inside and outside the car is quite large. The driver turns on the recirculation, and through the air duct system, well-heated air from the passenger compartment begins to flow onto the windows. When it hits cold glass, it instantly turns into water particles (condensate), and the glass fogs up. In theory, a working air conditioner can prevent fogging – it dries the air. But this is not always enough to keep the glass clean and transparent.
Considering all the factors, it is better not to press the air recirculation button in the rain – excess humidity in the cabin is useless.
The recirculation button can be labeled differently. The most common pictogram options are in the photo below.
How to prevent fogging of windows in the car?
To get rid of fogging, drivers often open their windows – this allows to reduce the temperature difference between inside and outside the car. It is also recommended to reduce the temperature on the climate control unit.
But these are the most simple and well-known methods of dealing with misted windows. There are others – read about them at this link.
When can air recirculation be used?
If a bus or truck with smoky exhaust is driving in front of you; In hot weather, for faster cooling of the passenger compartment immediately after turning on the air conditioner. In winter, to accelerate the heating of the windshield and interior.
It is not recommended to use the recirculation function for a long time, because the air in the cabin that passengers and the driver breathe will be stale.
5 things that will bring drivers to white heat. “Behind the wheel” can be viewed on YouTube.
Photo: Casey Horner / Unsplash and production companies
