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Power Science

Vertical Axis Wind Turbine With Push and Pull 374

Sterling D. Allan writes "After 10 years of prototyping, wind tunnel testing, patenting, and tweaking, Ron Taylor of Cheyenne (windy) Wyoming is ready to take his vertical axis wind turbine into commercial production. Design creates pull on the back side contributing to 40%+ wind conversion efficiencies. Because it spins at wind speed, it doesn't kill birds, and it runs more quietly. It also doesn't need to be installed as high, and it can withstand significantly higher winds (can generate in winds up to 70 mph, compared to ~54 mph tops for propeller designs). Generating costs estimated at 2.5 cents per kilowatt-hour, putting it in the lead pocket-book-wise not just of wind and solar, but of conventional power as well. Production prototype completion expected in 5-7 months."
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Vertical Axis Wind Turbine With Push and Pull

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  • Sorry... (Score:5, Insightful)

    by utexaspunk ( 527541 ) on Tuesday November 08, 2005 @08:40AM (#13977800)
    ...but I don't take anything "Open Source Energy News" posts seriously anymore. It seems like every post that comes from them is a crackpot.
    • ...but I don't take anything "Open Source Energy News" posts seriously anymore. It seems like every post that comes from them is a crackpot.

      Gee, ya think? Next you'll tell me that the interesting newspapers in the supermarket checkout don't perform rigorous fact checking. And I was so hoping to meet Elvis and bigfoot.

    • Whilst this has a large amount of vapourware about it they do at least have working prototypes. Given the high profile of windfarms in the UK I can see more efficient designs being taken up in a big way. It may be a bit early to bet the farm but I wouldn't be surprised to see these on an off shore site near you in the next few years.

    • Re:Sorry... (Score:3, Interesting)

      by tgd ( 2822 )
      Whats really bizarre is the sudden influx of them.

      This has been an epic last few weeks for the ability of crackpots to get pseudo-science posted on here. I suspect its actually just a game the editors are playing -- trying to see how riled up they can get everyone. I suppose, though, its possible its just another example of why Slashdot either needs new editors or story moderation.
    • Re:Sorry... (Score:4, Insightful)

      by zippthorne ( 748122 ) on Tuesday November 08, 2005 @10:33AM (#13978367) Journal
      How is this open source? Pictures are not shown because it is patent pending and every other paragraph mentions something about the patents, at one point proudly mentioning that they are sufficiently broad to make an attorney happy (because they'll mean lots of work for the attorney?).

      But my question is, if it has a patent pending, why don't they publish? I thought that the whole reason for patents was to encourage people to publish their inventions. If the patent is pending, what's the risk?
      • If the patent application's been filed it should be available for all to see. Should ask them what the patent number is so we can look it up.
  • by __aagctu1952 ( 768423 ) on Tuesday November 08, 2005 @08:45AM (#13977816)
    While vertical axis wind generators aren't new - the Soviets utilized vertical designs for the most part - this design is. Wind power usually isn't practical or environmental for large-scale deployment (land usage/kW is too high), and I expect this design won't change that, but it could make wind an even better choice for microgrids [].
    Shame the article reads like Yet Another Slashvertisment (someone wants venture capital I guess) - I'd like some more details.
    • by otter42 ( 190544 ) on Tuesday November 08, 2005 @08:56AM (#13977875) Homepage Journal
      This design isn't new. It's bunk. As he describes it, it's a Savonius windmill, which is nothing if not inefficient.

      Although your comments about microgrids are very apt. And since what we truly need in this world are microgrids (encourage conservation of energy, reduce fossil fuel use, provide energy to Africa), I'm very excited about wind's possibilities in this arena.

      (Which is why I just started a PhD. in solar and wind microgeneration cells.)
      • by Kadin2048 ( 468275 ) <slashdot,kadin&xoxy,net> on Tuesday November 08, 2005 @09:17AM (#13977956) Homepage Journal
        Thanks for the info. I had never heard of Savonius windmills before -- or at least not heard the name. I've actually seen one before though, but not for any practical purpose: one of those annoying moving-lawn-ornament type things.

        In case anyone else is interested in what a Savonius windmill is, there's a page with a little simulation of one here []. I think they're selling something (model turbines maybe?) although I didn't really check it out.

        I have to wonder though whether one of these is really as efficent as a propeller-type windmill, given that a propeller type one can alter its blade pitch and keep the rotational speed relatively constant in different wind speeds. Is there a way to do that with a Savonius design? It doesn't seem like the airfoils are really anything that you could easily change in flight.

        I'm not sure if it's true, but I once heard an interesting factoid about Dutch-style propeller windmills, and how they were among the first mechanical devices to implement a "feedback loop"; you have a tail rotor mounted perpendicular to the main rotor, which drives the mechanism that orients the windmill. If the wind isn't blowing at the mill directly from the front, it causes the small rotor to turn, turning the mill into the wind. When the mill is pointing in the right direction, there's no wind on the small rotor, so it stops. Pretty brilliant, for the 17th or 18th century.
        • I have to wonder though whether one of these is really as efficent as a propeller-type windmill, given that a propeller type one can alter its blade pitch and keep the rotational speed relatively constant in different wind speeds. Is there a way to do that with a Savonius design? It doesn't seem like the airfoils are really anything that you could easily change in flight.

          From my readings, and as a pilot, I can hazard a guess that this is because of the enormous complexity both in manufacturing and in mainte
        • by BlowChunx ( 168122 ) on Tuesday November 08, 2005 @09:34AM (#13978037)
          Just looking at the prototype from the article, it looks to me like they have "inlet guid vanes" which would direct the incoming air so that it hits the rotor blades at the correct angle, so there would be no need for variable angle of attack (as there is with propellers...).
        • by Anonymous Coward on Tuesday November 08, 2005 @10:37AM (#13978385)
          There have been wild claims for savonious rotors for many years. One, in Mother Earth News back around 1976 or thereabouts claimed 6 kw output for a machine made of two split oil drums, around 3 feet in diameter and 6 feet tall -- that's 18 square feet of frontal area. Power goes with the dimension squared (for circular frontal area) and speed cubed, so, double the dimension (radius, diameter), you see 4 * the area and thus 4 * the power available. Double the speed and you see 8 * the power available, all given some constant (never happens) coefficient of conversion.

          Roughly, power = 1/2 * rho * v^3 * a * k * c
          where rho is mass density of air, v is windspeed, a is area, and k converts all units to power units. If you use square feet and feet per second as units, and 0.00238 slugs/ft^3, then you need to know that 550 ft-lbs/second will convert to horsepower. "c" is the conversion coefficient, typically around 0.25 for a good bladed rotor, probably closer to 0.1 for a savonious. I have built and seen rotors that did better than 0.3. Factor in loss due to generator power conversion, transmission line losses, etc, and things go downhill from there.

          In general, there is a Betz limit that says, mathematically, that the most you can ever harness from a fluid flow such as wind is 59%, though there are suspected ways around that. When these people deride "tip speed ratio" they are giving up the fact that, when you can travel faster than the wind, as does the outer regions of a bladed turbine, you have the opportunity to generate more power due to the lift-to-drag ratio of high aspect ratio blades (wings) providing lots more torque than you would get by mulling along at around the same speed as the wind. Take a look at those multibladed farm water pumpers. They have a tip speed ratio rarely greater than one, and their conversion efficiency is fairly low. They're good for high starting torque to lift water. In electrical generation, you don't worry about starting torque because generators don't "kick in" till you're flying fairly fast. There is one aspect to the claims in the granted patent: he adds external "airfoils" to direct more wind into the central sevonious rotor, speaking of which, it's hard to tell from the pictures, but he may miss one nice point about generalized savonious rotors: the gap in the middle. If he closed that, he loses a lot due to the "airfoil" effect of the retreating (driving) blade directing some of the airflow through the gap into the advancing (dragging) blade (cup if you like).

          In some sense, what he claims in his patent is well known in prior art. It's a lot like those dumbass patents the USPTO is granting these days for stuff like "one click", or "shopping carts" -- those folks in the USPTO never go outside and smell the roses. The patent presently granted can be stomped all over with photos from even ths us department of energy archives.

          Dumb stuff like this comes along all the time. I don't think this is the work of a charlatan; rather, it really appears to be the work of an honest, but not well educated fellow. Clever, but not original or novel (novel to him, not to the rest of the world). Too bad every time someone comes along with a perpetual motion machine or something close (really cheap energy), they have to slam everything else that's already out there.

          An earlier poster here commented on the apparent low quality of the website that printed the press release. Too bad about that. I'm reminded of the somewhat childish but good hearted efforts, long before the web, in the late 70's following the huge gas pump crisis in the U.S. Everybody and his uncle started printing journals, whatever, including The Mother Earth News. Some of it was good, some of it was rubbish, but we all had a ton of fun doing it. Looks like what goes around comes around. Again.
          Jack Park
        • Pretty brilliant, for the 17th or 18th century.

          I suppose Leonardo da Vinci pretty smart, "for the 15th century".

          I'm sure you didn't mean it, but that's pretty patronising. People were making ingenious use of wind power long before the 17th century, for example the use of tacking [] to sail against the prevailing wind. They only reason ideas like this seem simple to us is because we've had exposure to the creativity of previous generations.

      • I bow to your superior knowledge. :)

        That's what I get for speaking out with only a superficial knowledge of turbine design I guess...
      • "As he describes it, it's a Savonius windmill"

        I don't get it. I looked up Savonius Windmills (with google) and they seem to be different in at least a couple of important points.

        Can you explain the differences, and why they don't matter in making this a Savonius windmill?
      • by brentcastle ( 807566 ) on Tuesday November 08, 2005 @01:19PM (#13979903) Homepage
        Yeah, I was quite shocked to see this. Even more shocked to see that he has patents for it. I worked on a vawt for awhile. There are about a 1000 different variations online by diy'ers. Savonius originally patented something that looks essentially identical to this device in the 20s! From my experience its great in areas where you have a low constant wind. Tip speed sucks, but you can get more torque with this device. It works great in an area with lots of flat like where I live (Indiana). I believe it was originally designed to be used to grind grain on farms.
    • plenty of room in the sea for offshore usage surely?
    • Large-scale solar deployments can be in places like ranches or farms and can be used to suppliment a farmer's income. Explain how this isn't practical or environmental.
    • by Lumpy ( 12016 ) on Tuesday November 08, 2005 @09:40AM (#13978057) Homepage
      yes and no. the best wind generator is the vertical axis generator. it removes a significant amount of complexity and can be easily made from junk lying around most farms. 55 gallon drums cut in 1/2 make the blades easily(plastic ones are best) and a belt/pulley system to a car alternator makes an inefficient version, you can make a highly efficient version that will produce usable power at only 6-8mph winds if you make your own coil pack and greater your permanent magnet stators with the surplus high power jobbies available most anyplace.

      I helped erect one in northern Michigan, it can generate 106 watts in the calm days from the natural constant wind going up their hill and generated almost 1.8Kw peak during a storm before it threw the belt off.

      no complex wiring to couple a spinnable generator to the power coming down, dirt simple and works at only 40 feet off the ground. if you paint them white they look pretty nice and can be built in a day if you don t build the alternator yourself.

      personally I am surprised there are not more of them compared to the highly complex spinning blade setup that must pivot to follow the wind.

      Who cares if the more complex is more efficient, if I can build 20 of mine for the price and effort of 1 typical wind generator I'll end up ahead.
      • These things don't look like they scale up very well. Wind power is all about swept area - or in this case profile area. To get more power you need more volume of air moving past. How does this type of design scale? Or is it limited to home use?
        • Re:Scaling problems (Score:5, Informative)

          by Lumpy ( 12016 ) on Tuesday November 08, 2005 @11:09AM (#13978633) Homepage
          it scales vertically. we built one with 6 55 gallon drums. 3 on the lower tier 3 on the upper tier cut in a way to have 6 blades per tier. all attached to the central shaft using a thrust bearing at the top and botton and then to a pulley that turns the rotor on a home built alternator at 3 times the rpm that the windmill is spinning at.

          works great. put another next to it and now I get 2X the power generating capacity. add 3 I get 3 times the power generating capacity. that's the neat part 1 windmill does not slow down all the wind and scaling up works perfectly when you think of it in a multiples instead of one giant windmill.

          a small village trying to be seld sustaining could create a farm of these and generate power. wind is not the only source you need, you have to couple it with solar. because the days it's not windy it's usually very sunny. and all of it needsto go into a storage system.

          Typically simpler = better. because you can make more of them to compensate for the lack of efficiency that highly complex may or may not give you.

          that's the problem with alternative energy, too many people make it complex as hell and scares the realy users away from it. Anyone can create a hang out your window solar heat collector that works fantastically well for about $19.00 in parts and a little time gluing, nailing and painting. But you only see the hyper expensive requires engineers to install systems advertised or talked about. same as solar electricity. you can buy your solar cells for pretty darn cheap, you do not have to pay $5000.00 per panel for new state of the art stuff.

          Same as you do not need to be a aeronautical engineer and able to carve an airfoil propeller to make a good working windmill.
          • Only somewhat (Score:3, Interesting)

            by bluGill ( 862 )

            Your points are true only on a small scale, they fail on anything large.

            All windmills slow the wind. If you add a second windmill, and the wind is blowing such that it would go from one to the next (in absence of any windmills/trees/buildings), the second windmill will see slower wind than the first, and thus generate less power.

            All windmills create turbulence zones around them, mostly downwind. This too decreases the efficiency of the windmills downwind.

            The only solutions to these problems is to space

    • by Clueless Nick ( 883532 ) on Tuesday November 08, 2005 @09:46AM (#13978085) Journal
      Well, here's blowing a razberry at you, kid. Are you a votary of the oil lobby?

      Land usage / kW for wind turbines is NOT too high. You only actually need half an acre/MW. The rest of the land is for wind easement, and you can carry on farming/horticulture without much interruption on it. And this is true only for Europe and N. America.

      In developing countries, windy land is mostly arid, mountainous, or coastal - nothing much grows there.

      Large scale wind developments are economically viable. Wind gets the minimal of governmental support, and look at how it's growing. Lots of free tools are available on the web to see it for yourself - various HAWT models, various sites around the world.

      Large scale developments starting from 50 MW parks or higher can enable the manufacturer/service providers to provide efficient erection and commissioning services, on-site round-the-clock Operation and Maintenance services, SCADA operation and data communication to the investor/utility, etc.

      Distributed development of wind power projects over geographically distant areas can theoretically reduce intermittency, which is the usual FUD against wind these days. Avian kills are another FUD: what is the extent of ecological damage being caused by your conventional power plants? What is the submergence being caused by hydropower?

      About TFA, well, there is a huge amount of development taking place in both HAWT and VAWT technologies, with competition between generator and/or drivetrain philosophies. /. can randomly mention anything - maybe somebody is fishing for funny comments.

      HAWTs have a distinct advantage of exploiting the swept area and the power law index by increasing rotor diameters (blade lengths). VAWTs may evolve into simple designs without much need for regulation - there are some that offer inbuilt speed regulation by design. They can generate at any wind speed that the supporting structure can withstand. However, I am yet to see VAWTs catching up with HAWTs having rated capacities of decade-old standards.

      Some of the VAWTs of the type in TFA can be well suited for use in defence installations - I've myself suggested one design to a defence research official for distributed, arctic-condition, radar/thermal/sonic neutral generation needs at the world's highest battlefield. I don't know if they have researched it further, but they won't tell :-)


      Disclaimer: I work for a wind turbine manufacturer. However, I have stayed with them because I like the industry.
      • Wind gets the minimal of governmental support, and look at how it's growing.

        While that may be true in the US, I think you'll find that Wind gets a lot of governmental support in the EU, especially Germany and Britain.

        It makes sense, if you think about it. As far north as most of the EU is, Solar isn't as promising for the EU as it is for the US.
    • There's a note on the Wikipedia article you've linked to.

      This article has recently been linked from Slashdot. Please keep an eye on the page history for errors or vandalism.
  • Safer to birds? (Score:2, Insightful)

    by Anonymous Coward
    "Because it spins at wind speed, it doesn't kill birds..."

    Birds don't move at wind speed. Sounds like a recipe for a collision!

    • Worse than that (Score:5, Insightful)

      by ishmaelflood ( 643277 ) on Tuesday November 08, 2005 @08:54AM (#13977867)
      if the downwind blade is travelling at windspeed, it is generating no force (and admittedly killing no birds who are flying with the wind, ie balloons). But, that implies that the upwind blade is travelling at twice the windspeed, relative to the wind.

      So that little argument is rubbish.

      Actually, the whole article is not too bad overall, we certainly see worse in real papers (eg the Guardian's coverage of that hydrogen atom fraud).
    • Re:Safer to birds? (Score:2, Informative)

      by Rinnt ( 917105 )
      I think the idea is that it doesn't move as fast as a propeller: From TFA:

      One of the primary environmental drawbacks of the propeller wind turbines is that they kill birds. The tips of the blades spin much faster than the wind speed, chopping through the air sometimes at speeds of 200 mph. The birds generally just don't see them coming.

      The TMA vertical axis design flows with the wind, at the speed of the wind. "It looks like a building to the bird," said Taylor. "We've never seen a dead bird at our te
    • Let wind speed be denoted w, bird speed b, and obviously the speed of light, c.

      We can't tell if b > w will always be true, we're pretty sure b w will not always true, but I propose the most definitive statement I can on this subject is b c.
  • Directionless (Score:4, Informative)

    by LarsWestergren ( 9033 ) on Tuesday November 08, 2005 @08:45AM (#13977821) Homepage Journal
    Another obvious advantage of this design is that unlike a propeller, you don't have to turn them around when the direction of the wind changes...

    A couple of years ago I talked with an engineer friend about this when we got on the subject of alternative energy. This isn't a new idea of course, variations have been used above chimneys [] for a long time for instance. He told me then about the large number of advantages to this design. I don't remember if I asked him the question that pops up in my head now - why did the propeller design become the norm?
    • "Another obvious advantage of this design is that unlike a propeller, you don't have to turn them around when the direction of the wind changes..."

      Of course, turning turbines around has been a solved problem since forever. The disadvantage of vertical turbines is that the wind is so much faster at the top than the bottom, which makes half of the turbine essentially useless.
    • by jurt1235 ( 834677 ) on Tuesday November 08, 2005 @08:59AM (#13977884) Homepage
      That is because airospace engineers are the main designers of these kind of machines. They know propellers, have all the systems to calculate what is possible with it, and through old designs of windmills (from 1400AD or even earlier) the principles pretty much stayed the same.
      • by Dan Ost ( 415913 ) on Tuesday November 08, 2005 @10:42AM (#13978418)
        What you've said is so wrong, it's painful.

        Modern propeller turbines use lift to generate torque and efficiency scales up with propeller length. Verticle turbines which use drag (as the one in the article does) are not as efficienct to begin with, and their efficiency does not scale as you make them bigger. This is why the engineers don't make modern large scale wind turbines out of them.

        Old windmills used wind drag to generate torque. Modern wind turbines use lift to generate torque. Saying the principles are the same is like comparing a glider to fighter jet.
    • Re:Directionless (Score:5, Informative)

      by otter42 ( 190544 ) on Tuesday November 08, 2005 @09:04AM (#13977906) Homepage Journal
      A lot of it has to do with materials. VAWTs suffer from two notable stresses that are inexistant on HAWTs. 1) centripital forces and 2) vibration.

      1) These things spin *quickly*. Far faster than the windspeed. Now, that's not so much a problem in a propeller blade because all the mass is on the inside and the blade happens to be strongest here, too. But on a VAWT, all the mass is on the outside, meaning that there is a significant amount of energy stored as they spin round and round. This pull can quickly destroy the windmill, and apparently has caused a couple deaths (Or so I have read in the windmill forums. Caveat reader.).

      2) Because of the way the VAWTs spin, the mill is subject to pulsing as the blades change their angle of attack and speed with respect to the wind. Of course, this is reduced by having more blades which are thinner, (the ideal propeller being made out of an infinite number of infinitely thin blades) but the materials have limits and it seems that 2, 3, and 4 blades are all we can reasonably do. So the pulsing motion fatigues the support and can lead to failure.

      HAWTs don't suffer from these problems, although they do have other problems-- such as torque applied by gyroscopic precession, torque applied by higher windspeeds at the top of the mill than at the bottom, orientation into the wind-- but they don't seem to be as difficult to overcome as the VAWT ones.
      • Re:Directionless (Score:4, Informative)

        by Fordiman ( 689627 ) * <fordiman AT gmail DOT com> on Tuesday November 08, 2005 @12:18PM (#13979232) Homepage Journal

        I hate it when people don't read TFA.

        Apparently, this thing can handle going with windspeeds of over 154, while props fall must be braked or they'll fall apart. This likely has to do with the materials used.

        Also, the wind-tunnel testing gave them a number of 2 blades.

        That's the reason this _is_ news. This guy was able to overcome the inherent engineering problems with VAWTs (which are more efficient, but more difficult to design without the failures you described). The Slashdotters may think this is funny, or stupid, but...

        It occurs to me that every time a new non-software technology has been reported on slashdot, >50% of those who comment on it are near-psychotic in claiming it's bunk. Why is that?
    • Re:Directionless (Score:3, Informative)

      by Weh ( 219305 )
      Propeller designs have the advantage that the propellor is generating power in every part of it's revolution. The blades of vertical rotors will always have a position in which they move against the wind, which causes drag or tricky aerodynamics at best. My uncle already worked on machines like these back in the 80s, the aerodynamics of these machines are not so easy I think.
      • Re:Directionless (Score:2, Interesting)

        by otter42 ( 190544 )
        The blades of vertical rotors will always have a position in which they move against the wind, which causes drag or tricky aerodynamics at best.

        Actually, the blades are always moving agains a relative wind. What's tricky about the aerodynamics is that the relative wind constantly changes as you go round the circle. The solution to this is to spin faster, so that the wind component which changes (the real wind itself) is small in comparison to the wind component which doesn't (the relative wind produced tang
    • The non-directionality is as much a problem as it is a boon. A propeller driven turbine will turn if the wind speed is great enough. As long as it is pointing intow the wind and there is wind, it will do useful work. The typical design for a vertical wind turbine stalls if the wind falls below a minimum threshold and is not self-starting: the device must be spinning to recieve torque from the wind. In areas where there is a high, constant wind, this is not that much of a problem, but if the wind is high
  • by aussie_a ( 778472 ) on Tuesday November 08, 2005 @08:46AM (#13977822) Journal
    Ron Taylor of Cheyenne (windy) Wyoming is ready to take his vertical axis wind turbine into commercial production......Production prototype completion expected in 5-7 months.

    Now being the old fuddy duddy I am (at the tender age of 21) I'm obviously using an old and outdated definition for "ready for commercial production." See, the definition I'm using is one where the prototyping stage is over, and these things are being made in some factory and are about to be sold to companies/people. Now obviously not being up-to-date with the latest definitions, I was quite excited when I read it was ready, only to have my hopes dashed by the end of the summary.

    Why don't you call us old-timers when you actually have a commercial product?
    • Actually, the term Production Prototype *usually* means the first version actually built by manufacturing (as opposed to a hand-built version by R&D) ... so this suggests to me that they are pretty far along - they actually have a manufacturing facility in place, people trained, material lists finalized, procurement contracts, etc. Of course they could just be *calling* it a production proto ...

      • Actually, the term Production Prototype *usually* means the first version actually built by manufacturing

        I didn't know that. But even so, it's 5 to 7 months before the production prototype is even built, and they're claiming it's ready to become commercially available NOW. It isn't ready to become commercially available now. It might be ready in 5 to 7 months, but that isn't now.

        That was my beef ;)
        • 5-7 months and $20 million dollars is what it takes for the lawyers to draw up a viable contract for production, installation, service and maintenance of these things.

          Its not in-fact a terribly long times, I would say that is it quick. If you sent Boeing a request for 5 planes it would probably take longer before they started any production work.
  • No, this guy is not full of hot air. He's not all bluster.

    The technology does blow everything else away.

    Yes, it will succeed, and not just in vertical markets.

    It really took some gust to work on this.

    Now I have to go back to bed in a fit of self-loathing.
  • by Paul Fernhout ( 109597 ) on Tuesday November 08, 2005 @08:53AM (#13977859) Homepage
    From: []
    "Windside works, when others don't, with gentle summer breeze and in a violent winter storm. It works, when others are in deep frost. Windside produces electricity at least 50 % more in a year than traditional propeller models. All the year round. Many things make it extraordinary. And therefore it gives the best value for the money."

    Not sure what the differences might be. Winside apparently has been producing these vertical axis windmills for extreme environments for, they say, about twenty years. But they do seem costly. They use a helix type design for the blades, see: []
  • Lots of details (Score:5, Informative)

    by otter42 ( 190544 ) on Tuesday November 08, 2005 @08:54AM (#13977865) Homepage Journal
    And it's all... horseshit.

    What he's proposing is a Savonius windmill. A fancy aenometer. Which we already do much, much better with the Darrius approach. The maximum possible energy that we can get out of the wind is 59%. Savonius windmills are far, far less efficient, as they rely on drag, and not lift.

    Of course, he claims that it works off of lift, which-- if his mill even exists in reality-- it probably does, but the fact that it only gets "a little" boost from lift means that it is almost completely drag based.

    One problem that people have when visualizing a windmill is the question, "Why not do it like a paddle-wheel? Like on an old steam-boat?" Well, do you still see those old steam-boats tooling up the river and across the ocean. No? Maybe you should wondered why. It's because... surprise, surprise, it's less efficient.

    Not to mention the ridiculous claims about hurricane/tornado proof design. And the centripital forces it's have to undergo at these speeds. (Real VAWTs tend to be able to spin at such high speeds that they are explosively dangerous.) And the torque exerted on the bearing coupling of a several story high building when there's 150mph of wind pressing on the top. seems to be nothing more than a shrewd attempt to make fun of the /. crowd, by pulling us all in to wow at the latest, greatest power generation technique that's going to revolutionize our world.

    For some real information on VAWTs, check out For instance, 58 [], or [].
    • So I guess you won't be lining up to invest in this great new design?!

      [Just kidding. Thanks a lot for your thoughts on the new approach. It looks like you think it is more dubious than "Cold Fusion".
    • I was reading about this company a few days ago & I dug a little deeper because the info was sketchy.

      What I found (and this article leaves out) is that there are a few negatives that need to be considered.

      1. To do maintanence, you have to take the entire sucker apart in order to get at the bearings.

      2. Height: Wind speeds are not even across various heights. There is a serious potential for nasty stresses when the wind is going faster at the top of this turbine than at the bottom.

      3. I don't remember the
    • Did you say centripital force?

      (Has a heart attack and falls over dead)

      I'm sorry, you're using correct terminology and appear to know what you're talking about. I'm afraid I'll have to show you the door.

  • by jurt1235 ( 834677 ) on Tuesday November 08, 2005 @09:03AM (#13977898) Homepage
    Maybe I could adjust rotating doors in shops to this design. Than it can power the lights or something like that. With enough wind, people will get sweeped into the store by this system too.
  • by MajorDick ( 735308 ) on Tuesday November 08, 2005 @09:07AM (#13977922)
    Anyone Remeber the Cousteau Turbo Sail, same principal.

    Everything old is new again ? or just a case of two people reaching the same conclusion through trial and error.
  • by danharan ( 714822 ) on Tuesday November 08, 2005 @09:08AM (#13977924) Journal
    If not this particular company and technology, the prices they are giving are in line with most analysts' expectations.

    Like a lot of other technologies, this one is going down in price in a predictable way. Check out the wind energy data [] at, especially that last figure.

    The sector has recently been experiencing Hockey-stick growth [] in investment. It's pretty much inevitable that this is going to be cheaper than coal- and likely cheap enough to make hydrogen for when wind is low. Cheap, guaranteed price, non-polluting.

    Judging from nuclear's track record, it won't come close to wind. These turbines might not be the ones to put nuclear out of its misery- but wind certainly will play a large part (don't discount solar just quite yet).
    • I remember a time when stores that sold pet supplies online, and stores that delivered what you ordered online in an orange sack within an hour were experiencing hockey stick growth.

      So your point is?

    • For the sake of argument, let's believe the hype just for a moment. From TFA: ...the approximate sixty claims between the two U.S. patents awarded and a third pending, and numerous international patents secured as well. "Our patent attorney is very pleased with how broad our patent protection is," Taylor said.

      If the design is so revolutionary, more financially viable than conventional power, and better for the environment, then no doubt they'll make a killing financially whether they patent it or not, as th
  • by Starker_Kull ( 896770 ) on Tuesday November 08, 2005 @09:31AM (#13978010)
    This link is the nicest derivation I have seen online of Betz's law regarding the maximum effiency (16/27 ~= 59%) of any non-compressible mass flow capture device. At least the article doesn't claim to exceed it (40%, I think). But as for high drag-devices getting a better effeciency than a variable-pitch propeller? That sounds pretty suspicious. []

    On the other hand, if it can endure much higher winds than a prop installation, its OVERALL effeciency might be higher, because the energy in a mass flow is proportional to the cube of the wind-speed; so the 1% high wind speed tail of the distribution contributes a large portion of the total energy captured by the turbine. Of course, having a bit more REAL info would be helpful in determining if this is just slick FUD or something real. And when significant data is not mentioned, it does make one tend to think there is something to hide.
  • Vacuum doesn't pull. (Score:3, Informative)

    by jcr ( 53032 ) < .ta. .rcj.> on Tuesday November 08, 2005 @09:33AM (#13978028) Journal
    This design does not create "pull" on the leeward side. There is no such thing as a negative aerodynamic force.

    • While what you say is technically correct, I think one can still call a force due to reduced pressure relative to the surrounding a "pull". Otherwise one could also argue that a vacuum cleaner doesn't suck - the "sucking" is just the outside pressure pushing the air to the inside, since the pressure in the inside has been reduced by pushing some of the inside air to outside through a different way.
  • Flawed (Score:4, Interesting)

    by wasteur ( 889134 ) on Tuesday November 08, 2005 @09:34AM (#13978036)
    The energy you can take from the wind is proportional to the area of the device, and the cube of the wind speed. Three-bladed wind turbines are tall and big because wind is faster higher up, and so they can sweep a huge area. A three blade arrangement is aerodynamically optimal, getting closest to the Betz limit of about 59% (not 20-30% or whatever the web page said).

    Also, bird death is about 1 per turbine per year for current technology. This is about 9 orders of magnitude less than bird death from buildings/vehicles/airplanes etc., and that's not considering the enviornmental consequences on bird life of NOT using renewable sources...

    Dumpy little vertical axis machines may have limited uses in isolated installation, and for revolving advertising, but they are not practical for large scale generation. The rotor of a modern 5MW wind turbine is about the same size as an athletics track. Imagine how big this vertical axis machine would have to be to match the wind capture of this. If the alternative is to have many small devices, there would be a very large number indeed: this carries costs of electrical interconnection, massive maintenance overhead from trillions of puny alternators and gearboxes, all of which was probably ignored in arriving at the 2.5 cents per kWh.

    The only way to make money with this turbine is to be the poor guy's patent attourney.
    • Re:Flawed (Score:3, Insightful)

      The rotor of a modern 5MW wind turbine is about the same size as an athletics track.

      Yes, but it looks like a big propeller: the spokes that the wind is pushing on only cover a small part of that circular area at any given time. The rest is clear air.
  • I would like to call a halt to posting links from Open Source Energy. The site is run by crackpots and kooks who espouse completely insane ideas that have absolutely no basis in reality. It takes about 5 minutes of browsing for any reasonable person to determine this. Promoting this site is bad for slashdot. I do not joke when I say that posting links to this site is no better than posting links to some "intelligent" design site about new theories of evolution.
  • by dindi ( 78034 ) on Tuesday November 08, 2005 @09:59AM (#13978145)
    I am skeptic; it still looks like a meatgrinder to me. O.k it does not look like the propeller desigh that chops the bird, but when that thing is spinning at speed I am sure it pets the bird in the back as gently as a bud hits you with 50mph windspeed from the back ....

    just a visual observation, and probably they threw some chickens into their grinder before they claimed that.

    Besides being an asshole critic, I really appreciate the aspect of renewable energy paired with not being a traditional meatgrinder .......

    fact: did you guys know that costa rica is only using wind and water power? In fact we produce as much from these sources that CR exports energy to neighbouring countries; clean energy. In fact, while still considered a developing country, electricity coverage is the best in central AM, technically you have electricity everywhere. For US/European readers it is probably normal, but when you drive around in Panama/Nicaragua you canappreciate grid coverage here.

    OK, water energy creates some mess with the environment in some cases especially when you have wetlands, because dams can affect these in a bad way, but still better than burning coal or radiating, etc.
  • birds make a great fuel source.

    Why not kill two birds with one stone?
  • by internic ( 453511 ) on Tuesday November 08, 2005 @10:19AM (#13978275)

    This is the third post I recall by Stirling D. Allan recently, the others being

    The first in that list featured complete crackpot pseudoscience. The second seems to be of dubious scientific merit. A quick look at Mr. Allan's website [] shows they are involved with a number of other areas of pseudoscience (or to put it less kindly, scientific hoaxes) such as "magnet motors" and "zero point energy" (as an energy source). That together with the two other submissions he's made leads me to doubt the validity of the information in these "stories". The main problem, however, is that these are not balanced informative articles, but rather they seem to be little more than ads seeking venture capital. Furthermore, it looks like Slashdot is soon to become little more than a mouthpiece for [] at this rate.

  • by delfstrom ( 205488 ) on Tuesday November 08, 2005 @11:28AM (#13978791)

    Windaus Energy [] (Ontario, Canada) has developed prototypes of a vertical-axis wind turbine and are looking for places to install working demos.

    From an announcement they sent out earlier this year:

    Designed and manufactured by Windaus, this device and the attendant transmission system is the first three-vane helical concept to our knowledge. Some limited testing has been done by the company but no formal field-testing for commercial application has yet been completed.

    The prototypes are mounted with the larger models on wheeled trailers.

    The properties inherent to our design do not allow the outer edge of the vanes to exceed wind speed. They are virtually silent. They are not intimidating. The design relies on torque rather than speed, and many benefits are derived from this concept. Also, most of the "working parts" are housed at the base of the frame, facilitating easy maintenance and simple upgrades. Its operation mitigates many challenges facing conventional horizontal-axis turbines.

    Specifications are available on their website, including output, torque, power output. As other people have pointed out, there are some disadvantages to this style of turbine, but there are also some advantages. It looks far more suitable for local micro power than mega wind farms.

  • by Animats ( 122034 ) on Tuesday November 08, 2005 @02:01PM (#13980291) Homepage
    This isn't a new idea. Vertical wind turbines like that [] have been built before. They're not very good. A better vertical design is the Darrius parabolic vertical turbine. [] There used to be a few dozen of those at the Pacheco Pass wind farm, but they've been replaced with bladed units. Verticals have the advantage that all the equipment is at the bottom, but the side loads on the bearings are a big problem.

    There are several hard problems in wind turbine design. One is that, for large wind machines, wind speed may vary considerably across different parts of the blade area. This produces huge stresses in the blade system. Aircraft propellers and hubs don't have that problem, so technology borrowed from aircraft props didn't quite work. That's been solved, but it took years to get past it.

    A basic problem, one which this new design doesn't solve, is overspeed protection. Wind turbines above toy size must be able to deal with high wind conditions safely. Some turn sideways; some turn upwards; some feather the props. Brakes aren't enough. There's no way to feather or turn this new design. Even small turbines [] need, and have, overspeed protection.

    There are lots of wind machine designs that more or less work in a small size, but don't scale up to the point where they're worth building. There's a square law; double the blade length and get four times the energy out. So big turbines beat out little ones, once ths scaling problems are solved. Wind turbine size has been creeping up since the 1970s, from about 50KW to a few megawatts.

    A 1.5 MW unit [] was built in the 1940s, but it suffered a bearing failure within a year, then a loss of blade accident which threw a blade 700 feet. Only in the past decade have reliable wind machines in that size range [] been produced in quantity. With 2800 of their 1.5MW units installed, General Electric can be said to have solved that scaling problem.

    The big machines aren't simple. They have active yaw control, active pitch control, hydraulic brakes, AC to DC to AC variable frequency conversion, and lightning protection. But, at last, they work.

    So these guys are going to beat that with a little tin model that looks like something used to spin a sign in a used car lot. Right.

It's fabulous! We haven't seen anything like it in the last half an hour! -- Macy's