It's a bird, it's a plane, it's a wind generator! The latest innovation from Festo, the company that brought us the dragonfly drone, is a big departure from conventional wind turbines, as instead of spinning blades, it uses a pair of flapping wings to generate power.
The steady strong winds of spring are upon us here in southwest New Mexico, which turns my thoughts to that same wind's potential for renewable energy, especially on the small scale, for installation on residences and in urban areas, where wind conditions can be erratic and slow.
The argument about whether or not small wind turbines make sense for efficient clean energy production continues to be debated, but that hasn't stopped innovators from trying to produce a better turbine for low wind conditions.The Festo DualWingGenerator is one of those attempts, and although it looks like something more suited to flying than it does to capturing wind energy, the company claims it is has "remarkable outputs" when compared to other small wind generators, especially in common wind speeds between 4 and 8 meters per second (9 to 18 mph).
The concept behind the DualWindGenerator is inspired by nature's design, and uses the same principle that birds take advantage of with their flapping wings, but in reverse.
"The system’s principle consists of reversing the natural wing-beating principle: whilst birds generate the necessary power to move forwards in the air by flapping their wings, a stationary system like the DualWingGenerator can take the kinetic energy from the flow of air. The wind power creates a linear lifting movement here, which is converted into a rotary movement. With the aid of an electric generator, the system turns the energy produced into electricity." - Festo
The DualWingGenerator uses four wings, which work in tandem to generate rotary movement from the vertical movement of the wings, and because the wings rotate along their axis for optimal presentation to the wind, is said to be "self-optimising" and adaptable to changing wind conditions when combined with the company's intelligent control technology.
"The four wings are arranged on both sides of the central column. The two top and the two bottom wings are each positioned on the same motor-driven rotary axle, which is fitted on a slide. When the wind blows, the two slides move synchronously on the vertical guide in opposing directions: whilst the top two wings travel upwards, the bottom wings move downwards. The pair of wings on one side forms a functional unit, whose fluid-mechanical properties enable power to be generated in an optimal manner. At the apex, a servomotor turns the wings and they automatically move back towards each other."
The wing technology integrated into the DualWingGenerator was developed through Festo's bionic bird project, Smart Bird, which used wings that could not only flap up and down, but could also twist or rotate to differing angles to make the most use of changing wind conditions.
While electricity production from the wind is the most obvious use of the DualWindGenerator, the flapping wings of this device could also be used strictly for their mechanical energy, such as for water pumping or for generating compressed air for industrial purposes.