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."
Could be useful for microgrids (Score:5, Informative)
Shame the article reads like Yet Another Slashvertisment (someone wants venture capital I guess) - I'd like some more details.
Directionless (Score:4, Informative)
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 [fluesystems.com] 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?
Re:Doesn't kill birds? (Score:2, Informative)
This is unlike conventional wind turbines that chop through air too quickly for birds to see them.
You haven't RTFA have you? No, of course not, this is Slashdot after all.
Windside has something similar (for twenty years) (Score:5, Informative)
"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: http://www.windside.com/products.html [windside.com]
Lots of details (Score:5, Informative)
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.
opensourceenergy.com seems to be nothing more than a shrewd attempt to make fun of the
For some real information on VAWTs, check out otherpower.com. For instance, http://www.fieldlines.com/story/2005/10/7/63930/5
Re:Safer to birds? (Score:2, Informative)
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 test site." Likely this is because birds don't normally fly into solid walls.
Re:Could be useful for microgrids (Score:5, Informative)
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.)
Re:Directionless (Score:3, Informative)
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.
Propeller design as the norm (Score:4, Informative)
Re:Directionless (Score:5, Informative)
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.
Looks like a TurboSail to me. (Score:3, Informative)
Everything old is new again ? or just a case of two people reaching the same conclusion through trial and error.
Re:Directionless (Score:3, Informative)
Re:For some values of "ready" (Score:3, Informative)
Betz's law and effeciency - (Score:4, Informative)
http://www.windpower.org/en/stat/betzpro.htm [windpower.org]
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.
Comment removed (Score:3, Informative)
Re:Could be useful for microgrids (Score:5, Informative)
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.
Re:Birds... (Score:5, Informative)
If you google for Altamont Pass, you will find reports of what is apparently the most deadly wind farm for raptors in the U.S., and kills about 800-1300 birds of prey a year. It's the farm's location in this pass, a migration path for other birds which makes it a great home for many raptors such as golden eagles, that makes it high risk. It's the small size, tight placement, and old design of the turbines that turns that risk into actual dead birds.
Your intuition is correct here, in that this is a tiny amount compared to the number of birds that crash into windows of buildings in your average city. On a per-turbine basis, cell phone towers kill more birds.
However, many people have taken the issue seriously (the makers of the Altamont Pass turbines were taken to court to force them to reduce the danger of their farms to birds), people like my father who as a bird watcher and conservationist is most concerned about predator populations due to their important role at the top of the food chain. It turns out that these concerns are being addressed, and newer turbines are much less dangerous to birds, in particular raptors. New designs discourage perching on the supports (electrocution of perching birds being a problem apparently), and larger turbines with commensurately slower blades, have proven to reduce bird fatalities.
This is an issue I care about, loving as I do large animals that eat other animals, and I feel it is being duley considered and addressed. Wind farms do less damage to the environment than any other form of power generation other than solar, and kill fewer birds than the windowed office building that would be built to house the adiminstration for any form of power plant. That's no reason not to pressure the makers of the farms to continue to address bird deaths by improving their turbines, but it's also no reason to discourage the construction of wind farms. People who are against wind farms due to bird deaths have in my experience fallen into two categories: concerned environmentalists who aren't aware of the scope of the problem, and industrialists who just want to have something to put in the "negatives of alternative energy" column to line up with "releases more radiation than Three Mile Island on a normal day of operation" in the "negatives of coal" column so they'll both seem equally bad.
Re:Could be useful for microgrids (Score:5, Informative)
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.
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
-clueless
Disclaimer: I work for a wind turbine manufacturer. However, I have stayed with them because I like the industry.
Re:Vacuum doesn't pull. (Score:3, Informative)
More modern turbines (almost) don't kill birds (Score:5, Informative)
Modern turbine designs have taken these problems (and many others) into account and now kill very few birds - probably fewer than are killed by flying into electricity pylons. The main design changes are that they are much larger and slower rotating, so birds tend to judge the motion correctly and avoid them. Correct me if I'm wrong, but I think the Altamont Pass turbines are painted grey to reduce their visual impact against the sky, which also reduces their visibility to birds. Modern ones tend to be painted white, which makes them more visible.
On a recent visit to Denmark I was very impressed by the size and sheer number of turbines, turning gracefully, slowly and fairly unobtrusively. Occasionally there would be a small, faster-rotating one of an older design. These were noticeably more distracting and attention-grabbing - particularly in the peripheral vision (which after all is designed to look for rapid movement from predators). It's these older designs that have lead to most of the complaints from local residents, and understandably so.
Give me a modern turbine at the bottom of my garden any day - they are also virtually silent unlike their older cousins.
Birds don't hover but bats do... (Score:5, Informative)
I was at the UK national Bat conference this years and there were a couple of presentations on bat kills around wind turbines. It turns out that the strange noised attrach insects and therefore bats. Certain wind farms in the use, I forget which, are on migration paths for bats. There is a suggestion that they turn off the wind turbines come migration session.
Since bats are a key part of bug control, particularly in the US, you might want to think about protecting them,
Lonely
I think Slashdot is being had (Score:5, Informative)
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 [pureenergysystems.com] 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 opensourceenergy.org [opensourceenergy.org] at this rate.
Re:Birds... (Score:4, Informative)
There is a recent NPR story on this here: http://www.npr.org/templates/story/story.php?stor
Re:Propeller design as the norm (Score:5, Informative)
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:Scaling problems (Score:5, Informative)
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.
Working version from Canada (Score:5, Informative)
Windaus Energy [windausenergy.com] (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:
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.
Re:Picked up by mainstream press (Score:3, Informative)
Darrieus VAWT commercial installations (Score:2, Informative)
http://web.mckenziebay.com/ [mckenziebay.com]
http://www.solwind.co.nz/vertical.htm [solwind.co.nz]
Re:Directionless (Score:4, Informative)
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:Not entirely sure.... (Score:2, Informative)
Re:Could be useful for microgrids (Score:4, Informative)
Why this design sucks. (Score:4, Informative)
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 [realgoods.com] 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 [energy.gov] 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 [gepower.com] 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.
Re:Sorry... (Score:2, Informative)
( it's: Allergy-free cleaning )
Re:Sorry... (Score:4, Informative)
http://www.fanwing.com/ [fanwing.com]
I think you should check your dogma.
"Windspinners" (Score:2, Informative)
When I saw the photo, I immediately thought of my local library's copy of a hippy-era how-to on building a vertical-axis wind generator out of 55-gallon drums, plywood and junkyard auto parts like axle bearings and alternators. It's called "Wind and Windspinners: A Nuts and Bolts Approach to Wind-Electric Systems" by Michael Hackleman.
Basically, you cut the drum in half longways, and then offset the halves from each other to form an "S" shape with the two halves overlapping slightly, so that wind enters the open side, follows its contour into the closed side and exits out the back. The book recommended stacking 3 such drums, offset 60 degrees from each other and with plywood circles between the drums to prevent spilled wind. If you want to get fancy, you build sprung gates into the backs of the drums so they can dump excess wind in a storm. There are some drawings and photos of the design here [redjar.org].
I think Hackleman's reason for championing the Savonius design had nothing to do with efficiency - instead, it was all about cost, simplicity and durability. Fits right into the microgrid idea - a small village in the third world could assemble a few of the cheap homemade versions of these and link them to a battery bank to get themselves some simple, reliable electricity for whatever they needed to power.
Re:Sorry... (Score:1, Informative)
Re:Sorry... (Score:3, Informative)
In the other type [wikipedia.org], "Because they are drag-type devices, Savonius turbines extract much less of the wind's power than other similarly-sized lift-type turbines."
I only skimmed the TFA but the pictures make it look an awful lot like a Savonious rotor.