The well-worn phrase of being seen and not heard could easily apply to Ziehl-Abegg’s new bionic bio-fan – the FE2owlet. The designers of Ziehl-Abegg have been observing many creatures whose bodies are optimised for water or air flow. The engineers were struck by the quietest of the birds of prey – the owl.
Just why is the owl so quiet? The owl hunts at night when visibility is very poor. Owls therefore locate their prey by hearing. And this only works if they can fly extremely quietly.
How do they do that? A barn owl, for instance, weighs around the same as a pigeon. Their wings, however, are several times larger and more arched. This gives the bird much more uplift at lower speeds. Pigeons, on the other hand, have to flap their wings hard, which makes them audible from afar.
The tips of the owl’s wings are also fringed. This causes the air flowing over and underneath the wings to meet at the rear edge of the wings more gently and therefore more quietly. The rear edge of the fan blade is serrated for the same reason.
However, the Ziehl-Abegg designers did not scrutinise owls only. Vultures, eagles and storks raise individual feathers; these create small border-vortices at their tips, further reducing the resistance of the wing. You can also see this in aeroplanes whose wings now have a small nick (or winglet) at their tip. Ziehl-Abegg owlet fan-blades have long had this feature.
The combination of several bionic features in a single fan also reduces the energy consumption in operation. Ziehl-Abegg’s FE2owlet blades can be combined with its ECblue (electronically commuted) external rotor motor, which gives the highest motor efficiency and high flexibility due to add-on modules. The FE2owlet has been integrated with the ZAplus for further advantages. The intelligent fan system consisting of the FE2owlet axial fan, ECblue or AC motor and guide vane, provides maximum efficiency and flexibility for any application.
Peter Fenkl, CEO of Ziehl-Abegg, said: “Our core competence at Ziehl-Abegg is producing electronic motors… In recent years we have focused very much on bionic designs and there we found that especially as the owl as the predator who hunts at night needs very quiet aerodynamic wings. Now a typical fan has a straight edge and we had a serrated edge developed; so one of the major benefits of the fans is of course energy saving and the other thing is that you don’t hear them.”
He added: “Today we create an environment that people really think and breath and live innovation. This is one of our core genes.”
David Miller (top right), managing director of Ziehl-Abegg Middle East, said that clients are now realising the benefits of having quality moving components within their equipment.
“I strongly believe that the market is moving towards an energy conscious, quality conscious way of thinking,” he said. “End users are becoming far more interested in the return on investment when considering sustainable technology.”