... life span. 3)Energy saving. 4)Simple and easy installation. Roof mounted industrial fan driven by wind Specifications of Aipu 24'' industrial ... design, which can make the industrial fan adjustable for the roof with 0-22.5 degrees.4. Environmetal protection, energy saving ... fan should be installed on the roof, operated by the power of wind, no need of electric. 24" Industrial Fan Mounted On Roof