This is a combination of both natural & forced ventilation system. It functions as a natural ventilator when there is a difference in thermal or wind pressure between the inside and outside of the building which forces the air to move through the opening of the ventilator. Industrial activity generates heat and hot air being lighter moves upwards. The lighter air get accumulated in the turbine of the  wind ventilator. As the hot air tries to escape from the turbine, it exerts a backwards thrust on the vanes and sets them in a rotational movement . When the ventilator blades rotate the turbine it gives rise to the centrifugal force and creates a vacuum inside the turbine . The partial vacuum is replaced by strong upward forceful movement of the wind . As the hot air is thrown out, fresh air starts entering through windows and door openings . This works for a perfect exhaust by wind driven ventilator thrown out, fresh air starts entering through windows and door openings.