Wind school. Placing vertically aligned turbines closer together gives more wattage for the buck.
Credit: Mariah Power
Posted on 11/25/2009 9:23:06 PM PST by neverdem
Wind school. Placing vertically aligned turbines closer together gives more wattage for the buck.
Credit: Mariah Power
Arranging wind turbines like a school of fish could reduce the amount of land they take up by 100-fold while maintaining their electrical output, say researchers. Wind farms based on the approach might also be considerably safer for migrating birds.
Whether it's Lance Armstrong bicycling behind his teammates in the Tour de France or a storm of fish slicing their way through the ocean, animals benefit from drafting. The leader breaks through the calm air or water, while the followers enjoy the reduced resistance in the leader's wake.
The same doesn't hold true for horizontal-axis wind turbines(HAWTs), the most common kind of windmill. Placing one HAWT in another's draft drastically reduces the efficiency of the trailing windmill. That's because the turbulent breeze created by the leading turbine's blades can't propel the trailing blades as well as an unobstructed airflow. So engineers spread the giant fans across hundreds of hectares of land--a practice that has created a backlash from people who find the turbines unsightly.
Turn a windmill on its side, so to speak, and the drafting benefit returns. That's what two fluid dynamicists from the California Institute of Technology in Pasadena have discovered. Robert Whittlesey and John Dabiri decided to study how a new type of generator, called a vertical-axis wind turbine (VAWT), stacked up against its more conventional counterpart. VAWTs resemble giant versions of the lawn ornaments that gardeners install to scare away birds and other veggie-loving critters (see picture). The researchers measured airflows at a prototype VAWT array in Glendora, California. They then compared that data with existing studies of how water flows through schools of swimming fish to see how geometrically arranging the arrays affected their performance.
Bunching up the vertical-axis turbines behind a leader pays off, Whittlesey and Dabiri reported yesterday at the annual meeting of the American Physical Society in Minneapolis, Minnesota. In fact, using a new mathematical model they developed from the Glendora data, the researchers found that arranging the VAWT arrays just like schools of fish produced the best results. Such tightly packed VAWT arrays can produce as much electricity as conventional windmills, all while using as little as one-hundredth of the land area. "I don't think I expected to see as great an improvement in the land use," says Whittlesey.
The study revealed that the most efficient arrangement involved alternating the rotational direction of the turbines: a clockwise rotation in the lead turbine, say, with two counterclockwise rotators next in line, followed by three clockwise rotators, and so on. Whittlesey notes that the models are preliminary, so even greater improvements might be possible with further study. And he says that the VAWT arrays could be much less deadly to birds because "the faster they spin, the more solid they appear," thereby allowing birds to see the turbines more easily and navigate around them.
The study shows "great promise," says mechanical engineer Lex Smits of Princeton University. Even if VAWT configurations achieve only half of the land-use gain as suggested, he says, "it would be a major improvement."
They’re still ugly and I would not want my local hospital to have to rely on wind “energy” for round-the-clock operations.
They’re running on one nut?
I look at those contraptions and think sliced and diced birds.
We could have resolved this in '04
That arrangement works fine if the wind is always coming from the same direction. If you put all of them on a big lazy susan and rotated it so the array was always pointing into the wind, maybe that would work :)
Why not Dale Earnhart Jr?
Libs would laugh the idea if drafting out of the room as a worldwide solution it it was Earnhart, but put a bicycler on the face of it and it is our energy salvation
a kernal of truth wrapped in enviroclaptrap
It aint gonna work.
In their model EVERYONE’S a winner.
Silly journalists/engineers/students: "new" is for something ...errrm, ugh, well, not old.
Mother Earth had plans for small scale vertical turbines back in the late 1960s/early1970s.
They also had plans for longitudinal turbines of the same basic design, laid flat on its side, and mounted lengthwise along the ridge of a roof.
Elephants in the room. Land mass and the wind dont always blow.
I propose we build the darn things on Whittlesey and Dibaris property.
Bournoulli shake his head.
but at what cost to production value?
A horizontally ducted system on top onf a building would be more aesthetically pleasing and most likely more efficient because the air is ducted.
I still dont think you can get your money out of it unless you can sell dreams to folks
. In fact, using a new mathematical model they developed from the Glendora data, the researchers found that arranging the VAWT arrays just like schools of fish produced the best results. Such tightly packed VAWT arrays can produce as much electricity as conventional windmills, all while using as little as one-hundredth of the land area. “I don’t think I expected to see as great an improvement in the land use,” says Whittlesey.
The study revealed that the most efficient arrangement involved alternating the rotational direction of the turbines: a clockwise rotation in the lead turbine, say, with two counterclockwise rotators next in line, followed by three clockwise rotators, and so on.
“these things have all been done in the study of cavetation”
Wouldn't they be storing energy for such times - and/or, not be the only energy source, but supplemental.
As for home use - If cap and trade goes through and they control your thermostat - there will a lot of folk who would dearly love some of these in their back yard.
You are proposing added cost for autonomy.
And thats all these systems are good for at the moment.
When the Govts done you wont even have autonomy, just the added cost.
It’s another scam in the subsidized wind power industry. To date, VAWTs must be built much larger and more expensively than HAWTs to produce the same amp-hours of power.
As for building horizontal axis turbines on my own windy properties, NIMBYs, shut up! You won’t stop me. You’ll all be out of revenues and resources soon and shouldn’t have made so many enemies with your anti-property-rights, socialistic, free-traitor, anti-family, anti-American ways.
Nag about one of my wind turbines, and the next ones will be built with gigantic, scary, wooshing rotor spans right next to the roads! There’s US Code against your invasions of property rights, and our lawyers will take your future communistic/fascistic revenues away for your meddling!
I go through this OVER and OVER with FReepers.
IT IS NOT EFFECIENT. Can it give you the personal edge? Yes, but it is not efficient
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