The gravity ventilators are used to the renewal of environment air, lowing the temperature and the dilution of the pollution (gases, steams, dust, others) of internal sources.

This equipment works with the uplift convection streams of the air, due to the temperature difference of the inlet and outlet air flow, and the difference of the piezometric pressure between the lower and upper inlet and outlet of the air passages.The equipment must be aerodynamic enabling its functioning to not be changed by the wind speed or direction in any internal and external condition. Since the ventilator operation uses natural thermodynamics forces, it is the most economical ventilation systems for industrial buildings.

The plant of the building, the location of heat sources or of air pollution, the weather conditions, the number of people inside and their activities, are factors that are used in the project and dimensioning of the ventilator.
For this project we need know:

- The kind of industrial activity;

- The number of air renovation per hour;

- The thermal gap between the inlet and the outlet airflow (t¹-t²);

- The difference between the height of the entrance and the outlet (H²-H¹) (piezometric gap).

These data are used for the project and dimensioning of the gravity ventilator, to guarantee the number or air renovation per hour specified.