Student science fairs, especially ‘high end’ prize technology fairs, can provide interesting windows on the passions of tomorrow’s scientists and visions of possible advances to come. The annual University of Texas at San Antonio (USTA) Texas Science and Engineering Fair (sadly sponsored by (with naming rights) ExxonMobil) is one such event that highlighted a wind power system reminiscent of Shawn Frayne’s Wind Belt from Humdinger Wind. In short, a winner of a 2007 Popular Mechanics Breakthrough award, the Wind Belt promises a very low cost path (several dollars of material per generator) toward wind-power generation via
a taut membrane fitted with a pair of magnets that oscillate between metal coils. Prototypes have generated 40 milliwatts in 10-mph slivers of wind, making his device 10 to 30 times as efficient as the best microturbines. Frayne envisions the Windbelt costing a few dollars and replacing kerosene lamps in Haitian homes.
The target is that very low power market requirement in the developing world that obviate the need for polluting lamps while enabling all the values associated with access to reliable (and extremely cost-effective) lighting. (See here for a 50-minute wind belt video.)
Energy was on the minds of several students, including Ryan Alexander, a sophomore from Plano, Texas. (Alexander will be skipping the next two grades and heading right to college in the fall). He developed a simple windmill that can be made out of bamboo or other plant materials and about one dollar’s worth of magnets, copper wire and alligator clips.
The description of 10th grader Ryan Alexander’s project Gone with the Windmills: An Analysis of the Effectiveness of an Oscillating Wind Energy Generator
Can a windmill for developing countries be created using local materials, such as bamboo, and can a windmill be created using aeroelastic flutter that can gather energy more efficiently in the developed world? In the project, models were created of the actual windmills: the turbine, an lattice tubular design, the oscillators- a natural version constructed from bamboo and a normal wooden one, a four-oscillator model, a high altitude oscillator, and a Darius oscillator. The models were tested in different environments and with varying wind speeds. It was hypothesized that the field of normal oscillators, which use aeroelastic flutter and do not have to contend with much friction, would produce the most electricity and the results confirmed that hypothesis. Both the natural and the normal oscillator produced around 240% more power that current turbine designs. The Darius design produced around 400% more power and the High Altitude Oscillator, 582% more power. The field of oscillators produced an outstanding 819% more power whereas the lattice windmill produced about 180% more power that the conventional windmill. This experiment is evidence that these technologies can advance the efficiency and capabilities of wind-driven energy generation. This data is very accurate with a statistical confidence level of 99.9% and its findings can be directly applied to the real world. With the use of an electric “kit’ containing the copper wire and magnets and local materials such as bamboo and leaves, developing countries will have access to clean, dependable, and cheap electricity.
Note that the ability to adapt any number of “local” (local around the world) products into the Alexander’s concept provides a path toward the low-cost Wind Belt approach.
Note that Alexander seems to have arrived at his approach independent of Frayne’s Wind Belt.
While playing the violin, Alexander noticed that the strings vibrated quite a bit without much energy input. Inventor and engineer Nikola Tesla noticed this “aeroelastic flutter,” Alexander said, which “could take down an entire building.” So Alexander’s windmill doesn’t bother with blades. Instead it is shaped like a long narrow box with four sides but no top or bottom. A thin material that will flutter in a breeze (such as a long, stiff leaf or a thin plastic strip) “floats” in the center of the box, attached at the ends to magnets and coils. When the thin material oscillates in the wind, the magnets move, generating an electric field. Alexander built a small, standard turbine windmill with blades and also built five oscillator models. In tests with various wind speeds, the oscillator-based models produced between 180 and 819 percent more power than the turbine model. He also created a kit with the basic materials and a pictorial instruction manual that could be used in developing regions to create electricity. “The true breakthrough was using bamboo and leaves,” he said. “It’s the world’s first natural and cheapest windmill that can be made.”