Natural ventilation is provided by a combination of roof vents, wall vents, roll up walls, or drop walls. Wind pressure provides most of the energy for natural ventilation. Research has shown that above 80F there is normally measurable wind between 1 and 5 miles per hour.* As heated air expands and rises to the vent it escapes out the roof vent allowing cooler air in through a wall inlet or the roof vent itself to take its place.
The best ventilation is achieved by air blowing in a windward vent and being allowed to escape through a leeward vent. Wind can also create a negative pressure along the roof to suck air out while letting air in the same vent or in the side vents. Even without wind, roof vents can cool due to the expansion and rising of hot air.