1. What is a natural ventilation window (windmill for short):

The natural ventilation window is a device installed on the roof of the car to adjust the air circulation in the cabin by opening or closing.

It consists of one or more rotatable shaft-driven blades, which are equipped with fans and fans and other devices; there are several fan-shaped small doors or small windows around the blades; these doors and windows are opened when necessary to achieve air circulation. .

2. The principle of natural ventilation:

The air volume of the car is determined by the temperature difference in the cabin formed after the mechanical energy generated by the engine is converted into heat energy and the airflow energy is balanced with the heat load inside the car:

(1) When the vehicle speed reaches above 80km/h, the heat inside the vehicle will increase rapidly due to the increase of engine power;

(2) In this case, if only the air-conditioning system is used to cool down, the effect is not good.

(3) The use of the physical characteristics of the vehicle itself to make the air flow over the surface of the body to generate convection to achieve the effect of heat dissipation is the so-called natural ventilation.

3. Advantages of natural ventilation:

(1) The fan blows the inhaled air out from the top of the car, thus playing the role of ventilation. This ventilation process will not change any structure and performance parameters of the car.

(2) The replaced exhaust gas will not pollute the environment when it is discharged into the atmosphere, and the energy can be recovered and reused.

4. Disadvantages of natural ventilation:

1) Since there is no cooling function, it cannot be used in refrigerators or freezers.

2) Not suitable for use in high temperature weather. Because opening and closing the door at this time will cause the glass to break.

3) It cannot be used normally in rainy or snowy weather.