Wind Drive Turbo Ventilators have oval aluminum metal vents . Even just a little bit of wind can be just enough for the turbo ventilator to rotate. The speed of the turbine is directly proportional to the speed of the wind.
The hot air inside the shed tends to rise up. When the turbines rotate, they suck the warm air out through the vent, thereby, bringing out a drop in temperature in the shed and allow supply of fresh air through doors and windows.