3.3: Axial Fan
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Axial fans are designed for moving low volumes of air under low static pressure conditions.
In their most basic shape an axial fan resembles an airplanes propeller, and simple household fans utilize this design.
While the propeller design is the simplest, there are other styles of axial fans. The tubeaxial, which is simply propeller-style blades installed in a ducting tube to help direct and focus air flow, and the vaneaxial, which incorporates air straightening vanes down behind the blades, and boasts the highest efficiency of the axial fans.
Due to their lower power requirements, axial fans are usually powered by single-phase AC motors which are either driven directly or via a belt system. They are generally quiet in operation and are favoured in places where noise levels are a factor, but are not suitable for moving large volumes of air.
These styles of fans are often used to drive fresh air over the condenser coils in rooftop units of air conditioning systems.