Crackpot ideas often come from academia because schools have a lot of really smart people who are under little or no pressure to make something actually work. And of all the alternative energy ideas, the lousiest idea that will not die is the eggbeater wind turbine. So now we see some new bogus claims being made by an aero professor from Cal Tech.
Wind-Turbine Placement Produces Tenfold Power Increase, Researchers Say
ScienceDaily (July 13, 2011) — The power output of wind farms can be increased by an order of magnitude -- at least tenfold -- simply by optimizing the placement of turbines on a given plot of land, say researchers at the California Institute of Technology (Caltech) who have been conducting a unique field study at an experimental two-acre wind farm in northern Los Angeles County.
A paper describing the findings -- the results of field tests conducted by John Dabiri, Caltech professor of aeronautics and bioengineering, and colleagues during the summer of 2010 -- appears in the July issue of the Journal of Renewable and Sustainable Energy.
Dabiri's experimental farm, known as the Field Laboratory for Optimized Wind Energy (FLOWE), houses 24 10-meter-tall, 1.2-meter-wide vertical-axis wind turbines (VAWTs) -- turbines that have vertical rotors and look like eggbeaters sticking out of the ground. Half a dozen turbines were used in the 2010 field tests.
Despite improvements in the design of wind turbines that have increased their efficiency, wind farms are rather inefficient, Dabiri notes. Modern farms generally employ horizontal-axis wind turbines (HAWTs) -- the standard propeller-like monoliths that you might see slowly turning, all in the same direction, in the hills of Tehachapi Pass, north of Los Angeles.
In such farms, the individual turbines have to be spaced far apart -- not just far enough that their giant blades don't touch. With this type of design, the wake generated by one turbine can interfere aerodynamically with neighboring turbines, with the result that "much of the wind energy that enters a wind farm is never tapped," says Dabiri. He compares modern farms to "sloppy eaters," wasting not just real estate (and thus lowering the power output of a given plot of land) but much of the energy resources they have available to them.
Designers compensate for the energy loss by making bigger blades and taller towers, to suck up more of the available wind and at heights where gusts are more powerful. "But this brings other challenges," Dabiri says, such as higher costs, more complex engineering problems, a larger environmental impact. Bigger, taller turbines, after all, mean more noise, more danger to birds and bats, and -- for those who don't find the spinning spires visually appealing -- an even larger eyesore.
The solution, says Dabiri, is to focus instead on the design of the wind farm itself, to maximize its energy-collecting efficiency at heights closer to the ground. While winds blow far less energetically at, say, 30 feet off the ground than at 100 feet, "the global wind power available 30 feet off the ground is greater than the world's electricity usage, several times over," he says. That means that enough energy can be obtained with smaller, cheaper, less environmentally intrusive turbines -- as long as they're the right turbines, arranged in the right way.
VAWTs are ideal, Dabiri says, because they can be positioned very close to one another. This lets them capture nearly all of the energy of the blowing wind and even wind energy above the farm. Having every turbine turn in the opposite direction of its neighbors, the researchers found, also increases their efficiency, perhaps because the opposing spins decrease the drag on each turbine, allowing it to spin faster (Dabiri got the idea for using this type of constructive interference from his studies of schooling fish). moreI have a VERY difficult time believing vertical wind turbines are any good--and the arguments in this article are especially lame. I mean, the claim here is that these things can be placed closer together than regular turbines because why? I don't know, maybe magic. I mean, if you actually harvest a couple of megawatts from moving air, how can there NOT be downwind aero disturbances.
You know, the airplane industry has been like this. Virtually everyone agrees that an airplane should feature a fuselage sitting on top of a wing with the control surfaces in the tail. The reason that configuration has won out is because it extracts the most performance. But every once in a while, some eccentric like Burt Rutan comes along and claims that control surfaces should be in front (canard) or that pusher props are better than tractor props, etc. And so they build an airplane that mostly reminds people why the standard version is the way to go.
Beech sold only eleven Starships in the three years following its certification. Beech attributed the slow sales to the economic slowdown in the late-1980s, the novelty of the Starship, and the tax on luxury items that was in effect in the United States at the time. In an effort to stimulate demand, Beech began offering two-year leases on new Starships in 1991.
End of the program
The last Starship, NC-53, was produced in 1995. In 2003 Beechcraft determined that supporting such a small fleet of airplanes was cost-prohibitive and began scrapping and incinerating the aircraft under its control. The aircraft were sent to the Evergreen Air Centerlocated at the Pinal Airpark in Arizona for destruction. Beech worked with owners of privately-owned Starships to replace their airplanes with other Beech aircraft such as the Premier I jet.
In 2004 Raytheon sold its entire inventory of Starship parts to a Starship owner for a fraction of its retail value.My guess is that the main reason you can place eggbeater wind turbines so close together is that they aren't doing a very good job of harvesting the wind energy. Of course, the main problem with the eggbeaters is that they are trying to harvest wind next to the ground which any cheap wind speed indicator will show, ain't much good.