Jet Engine Wind Turbine Design Could Halve Wind Power Electricity Costs
by Matthew McDermott, New York, NY on 12. 1.08
Until some carbon taxes or a cap-and-trade system pushes fossil fuel prices up to where they probably should be (if all the environmental factors are taken into consideration) any small thing that reduces the cost of generating electricity from renewable energy sources is great news.
A claim that a new wind turbine design could reduce the cost of generating electricity from wind power by 50%, and possibly double or triple a turbine’s output in the process is even better news. This is how it could happen:
Wind Forced Through Turbine Blades by Shroud
Technology Review describes how the FloDesign Wind Turbine works:
From the front, the wind turbine looks something like the air intake of a jet engine. As air approaches, it first encounters a set of fixed blades, called the stator, which redirect it onto a set of movable blades--the rotor. The air turns the rotor and emerges on the other side, moving more slowly now than the air flowing outside the turbine. The shroud is shaped so that it guides this relatively fast-moving outside air into the area just behind the rotors. The fast-moving air speeds up the slow-moving air, creating an area of low pressure behind the turbine blades that sucks more air through them.
The idea for this isn’t new, but past attempts to build similar turbines were limited by the fact that the turbine had to be very precisely aligned with the wind’s direction (3-4 degrees), but according to FloDesign’s CEO the blade design of this turbine allows it to work at angles of up to 20 degrees off the wind. Currently FloDesign just has a prototype, but a 12 foot diameter model for field testing should be ready by the end of next year.
Output Double That of Open Bladed Turbines
So where does the cost savings and increased power output come in? Because the shroud which surrounds the blades directs and speeds up the air hitting the blades, a turbine of a given size with this design can produce as much power as a traditional design with blades twice as large. This size reduction could mean that turbines could be spaced more closely together, increasing the amount of power an area of land could produce.
via: Technology Review
image: FloDesign Wind Turbine
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putting a tail fin on the back will keep it into the wind.
Ignoring the diffucults of erecting that thing, wind power is already limited by Betz Law. The maximum energy that can be extracted is 59.3% of what is in the wind. There isn't room in the math for a doubling of the power extracted from the wind.
@Jeremiah:
1: They said they came up with a 50% cheaper way to create electric from wind power.
2: Betz Law covers a blade spining in the wind. It doesn't cover other new types of technology. Like a system that modifies that section of slow moving air behind the blades. This system does that.
They have new technology that gets more air through the blades (and even have multiple sets of blades) then the old tech used.
Putting a turbo charger on your car gets more power out of the engine which changes how much power your car has. This is kind of like that.
Even if you need "only" a turbine half the size to produce the same amount of energy, you still have to make it 40m in diameter, and this design seems to use much more materials than a standard wind turbine.
I agree with Jeremiah. Beware of any claim the spouts wild numbers like "double" and especially "triple." There just isn't room for that kind of gain.
The key in this article is of course saying that you can put the turbines closer together. But they are already optimally placed so that one turbine has an acceptable effect on another.
The same argument is always brought up when discussing vertical axis turbines. If it worked better, they'd do it. It's about money.
@Jeremiah: Yeah, building something like that at even half the size of the megawatt+ turbines would be quite an engineering challenge. But this could be useful in small-scale wind applications where space is at a premium.
Check out the article link to technology review. it is a bit more thorough. it appears the shroud is effectively concentrating and speeding up the wind as it passes through the shroud, since power generated is equal to the wind speed cubed this explains (i believe) how the power can be doubled while still obeying Betz law.
These types of augmented turbines have been tried before. They do considerably increase the output from a turbine of a particular size, but remember, the augmentation ring or whatever requires a lot more materials to manufacture than would conventional turbine blades of the same diameter, so it begs the question, what's the point?
These machines are bulky and heavy compared to conventional machines, they are harder to slew into the wind, and they cost more to build. The higher wind resistance of the augmentation ring when hit by crosswinds also makes them more prone to damage, as one developer in New Zealand discovered a few years back.
All in all, a waste of time...
Seems to me if I understand the model correctly it would be a lot better if the turbine were mounted vertially and mold a shroud around it that directed the wind at it from 360 degrees.
Without a proper energy storage mechanism wind power is a faustian bargain. You can potentially save a little bit of natural gas at the cost of becomming dependent on future supplies of natural gas to create dispatchable electricity.
I'm sure the oil companies are overjoyed at their new security of demand for their natural gas; and I'm sure the coal companies are overjoyed at the fact that wind power creates the appearance that something worthwhile is being done for the environment(such that it may eschew potentially practical competitors to coal power like nuclear, geothermal, practical means of large scale grid energy storage and biomass).
The best all-round(including cost-effectiveness) electrical energy storage systems are still the lead-acid battery for vehicle and UPS use and pumped hydroelectric storage for grid energy storage; both technologies well over a century old. This is a very difficult problem and needs urgent attention; if you go on pretending that if we just put up enough wind turbines and solar panels global warming will be solved you're setting the world up to burn every last scrap of coal it can find.
@Lance T
All in all, a waste of time...
More or less what they said to Edison, when he'd made failed lightbulb #4999...? ;-)
These shrouds might be inflatable with helium gas or partially inflatable to allow retrofitting.
I would like to remind everyone that only a few decades ago, hydro-electric was the posterchild for "clean green energy". We all know how that turned-out, a complete failure, only a small % of our power needs. I fear we are making the same mistake with these huge industrial wind turbines, that for their size and cost are very inefficient, spin about 30% of the time and only harness about 5 % of the wind. Would we plant 100 acres of corn and harvest only 5