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Forum Index : Windmills : The Latest from ART Turbine
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| Drewartturbine Newbie  Joined: 09/08/2011 Location: Posts: 30 |
Hello all, I thought you might enjoy seeing the latest video, made for the Fast Company design contest. It features the new 16ft tall rotor, on which I'm just finishing the alternator. This turbine is the same basic geometry as the 8ft rotor you may have seen in my earlier video's, just much larger. It's also the first time I've tried integrating an alternator. The alt I'm building is 72 poles, with each pole being 2 1x1x4" ceramic magnets. I'm wiring so I can have many voltage output options, including over 100V for grid tie inverters. It should be able to reach 150V at 3m/s or just below. I'll post some more details about it once I get a bit farther along.. http://youtu.be/dj45xitF4I4 |
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Madness Guru  Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Do you have any performance data? There are only 10 types of people in the world: those who understand binary, and those who don't. |
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MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Drewartturbine First off, I know this is your 13th post, but welcome to the 4m anyway. I looked at the video and left you a comment there. Your design is very pretty and should be passable as "yard art" in places where turbines are frowned upon. Some performance data is definitely needed. My hunch is you will find it takes an enormous amount of wind to get this started against a load. I live on the plaines of Texas and the wind blows about 20 mph on a daily basis. Low air is turbulent air, so a VAWT makes a lot of sense for those of us who don't like climbing to break-neck heights to fix stuff. Trouble is, most VAWTs don't put out much horsepower. I'm about to change all that. I'll post the build as soon as I can. I'm just finishing up building my new house. The tornado shelter went in today. . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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| Drewartturbine Newbie Joined: 09/08/2011 Location: Posts: 30 |
Hello Madness (how often do I get to say that!), I have performance data from the earlier 8ft version, using an anemometer, a 360 step/rev position sensor, and a Proney brake connected to a load cell, all logged at 1000 htz. What found was that my max Cp was .3 (shaft power), at TSR about 1.3. in 10m/s wind I believe because of the favourable Reynolds number, and other factors in scaling up, that the performance of the newer larger version will be better. For comparison, the SWCC certifies the output of the Bergy 1 as Cp.31 (electrical watts), and the Skystream at Cp .3. So, if I can get good enough shaft power to watts conversion, then I will be in the company of the best commercial systems. This compares to other VAWTS, like the Windspire a low solidity Darius variant which was tested by an NREL facility as having a max Cp of .17 or the Helix, a high solidity like mine which is below Cp .1 @MacGyver, thanks, it is pretty isn't it. It actually has tones of startup torque, and spins up the 300lbs or so of magnet array in a 10km/hr wind just fine (you can see that in the video). It does worry me that such a big flywheel may keep it from tracking it's optimal TSR, but it also may have some advantages. I hear you about the turbulence, but high solidity turbines performance isn't affected by turbulence in the same ways as low solidity turbines. Only time and testing will tell however. Good luck with your VAWT |
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| electrondady1 Senior Member  Joined: 12/02/2009 Location: CanadaPosts: 208 |
drew, did you get your(ed's) 3phase sorted out? |
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| Drewartturbine Newbie Joined: 09/08/2011 Location: Posts: 30 |
I did sorta get it figured out that Ed's method works great, however if you (I) screw up the coil spacing, it's not great. I've got it working, but managed to mess up my coil size, so I have a less than perfect waveform. Not the end of the world, but frustrating. I am managing to get 5.5V post rectifier out of 1/4 of the coils (didn't wind them all yet) in 2.5 m/s wind. I am going to change my coil geometry, and am thinking of going with a sorta serpentine (again modular), and that should help. As soon as I have some good plots I will share them. The very good news is that my turbine almost burned through it's brake rope in winds of only 2-5m/s. It's definitely got more than 4x the shaft power than it's smaller version. |
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| electrondady1 Senior Member Joined: 12/02/2009 Location: CanadaPosts: 208 |
I'm using an overlapping 2 phase method now with two coils per pole and rectifying them separately. is it a secret as to what the construction material is? |
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| Drewartturbine Newbie Joined: 09/08/2011 Location: Posts: 30 |
I'm using the 3 coils per 2 magnet poles, as per Ed's description, however I made the coil set about 20% to small, so there is gap between coils, exactly what I was not trying to do. It's working ok though and I can correct it in the next group of coils. I'm rectifying after star wiring, and get a very smooth output, with a small dropout. No secret as to what my latest turbines are made of, just styrene foam, shaped, then in the smaller cases with a thin layer of glass and epoxy, in the large case surfaced with a sprayable 2 part urethane that I wouldn't use again. If I were doing it again, I'd likely do the cold moulded cedar as I did on a couple in the past. It's much faster than you would expect, and produces a very strong, very good looking turbine. |
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| Drewartturbine Newbie Joined: 09/08/2011 Location: Posts: 30 |
Hello folks, I've just put my website back up, and included a report done by UVic researcher Matt Hall, on his review of test data collected by engineer Jon Scott, and myself. I know some people have expressed interest in seeing it. you can find it at www.artturbine.com under the supporting documents tab, near the bottom of the page. I've also included links to the 1977 blackwell report, where it was reported that a Savonius type turbine reached about .2 Cp (20% efficiency) and a link to the thesis by Ian Ross 2010 where he explains the discrepancy between wind tunnel results and real world results in high solidity VAWTS. Best Wishes Drew |
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| anteror Senior Member Joined: 06/10/2009 Location: FinlandPosts: 189 |
THERE are of course people, who do not want, that we take power from wind. These are the savonius and vertical axis windpower vawt people.. 
Please read what Hugh Piggot and also what Paul Gipe have wrote. Both are the winpower gurus, in this world. Here is article, that will tell you; http://www.wind-works.org/cms/index.php?id=116 http://scoraigwind.co.uk/2013/02/the-truth-about-vertical-ax is-turbines/ Read this, there is really facts ! VAWT has nothing to do with energy production. IT is JUST garden decoration. Antero Finland |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
[Quote=Anteror]VAWT has nothing to do with energy production. IT is JUST garden decoration. NOT! 
. . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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| Drewartturbine Newbie Joined: 09/08/2011 Location: Posts: 30 |
Antero, Thank you for referencing both Paul Gipe, and Hugh Piggot, both I agree are hero's in the small wind world. They are both world leading experts in small wind power systems, and as such have seen many deceptively advertised turbines, both HAWT and VAWT, come and go. Before you comment on who I am, or what my technology is, I suggest you alleviate your broad brush mentality and read some of the information I have provided. Then if you are able to understand it, we may be able to have a discussion. If everyone responded the way you have to technological innovation, humanity would still be banging stones together. I agree that there have been many companies selling products, both HAWT and VAWT, whos claims didn't live up to their real production. That doesn't mean that all new technologies are always going to be deceptively presented or defective. |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi Drew The forum members here are a smart bunch and have seen a lot of windmill designs and idea's come and go. They are going to need to see real life power figures before the Art turbine gets a tick of approval. While its a nice looking turbine, it can only harvest so much energy from the area facing the wind, and these laws are well understood, see How much power can we extract from the wind, which applies to both VAWT's and HAWT's. The reason HAWT's are so popular is because they scale up easily and can create a large surface area facing the wind column. VAWT's are more difficult to scale up, compared to a HAWT, for the same energy return. But VAWT's can be more suitable in some situations, like in parks, on sides of buildings, in densely populated area's, etc. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| electrondady1 Senior Member Joined: 12/02/2009 Location: CanadaPosts: 208 |
drew,i gather your on Salt Spring island. the coast is a great wind resource. i live on Georgian bay, lake Huron, which is kind of famous for wind. 
i build vertical mills 'cause i live in town and like the away they look. i recall you began talking about a patent on your secret vertical design back in 2005 on the fieldlines otherpower forum. i believe you first revealed the design on you tube video back in 2011. in all that time, it seems odd that you could not get some kind of output figures. you seem to be bogged down on the alternator. with out getting sucked into the quest for a perfect alternator for your particular design, you could do a prototype using a dc motor and pulley system that would be close to revealing the watts it can harvest . have you completed the stator yet? can your alternator stop your windmill ? are you incorporating a manual break ? it's unclear as to weather you are looking for advice or just showing off ? 
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Crew This thread seems to be turning into one of those contests you perform in the wind. Savy? Most of us here are here just for fun. I like building stuff. Sometimes it works; sometimes (usually) it doesn't. Who cares? When things go south, it's usually obvious to everyone else and when it works, it's like icing on an otherwise delicious doughnut. We do this for the fun of it. Where it gets sticky is when someone feels they have something so cool, it is gueninely worth merchandising and they feel threatened by the rest of the crew perhaps "stealing" their idea. If that's the case, just don't be so fast to share things, right? For that, there are patents and so on. Get your patent, THEN share. The rest of us are for the most part (and I speak for myself here) just old farts, who enjoy playing in the shop, then doing a little show-'n-tell on the Interweb. That's about it. I like your turbine; it's awesome. It's pretty. I'd love one twisting in my yard, but I've been around long enough to see where it's going and if I want a VAWT, I'll just build my own, then hang something silly on it that will twist around in the wind and make the cows wonder what I'm up to. I don't have many neighbors to impress where I live. Gobs of cows, though. Anyway, if the shoe fits . . . well, you know. Meanwhile, the rest of us are going to keep on building and sharing. Hope you join us, but if you insist on making claims, like power output, you'll find you'll make more headway if you post a little proof. Post some output numbers; what could it hurt? . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412 |
Looks like he is getting lots of output... from the members, just not output numbers from his mill. I'll have to agree with the members at this point but reserve my judgment for a later time. I have'nt posted for so long I had to look up my pass word. Anyone building a VAWT has their work cut out for them is all I can say. Mac46 I'm just a farmer |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Yes it is a bit strange to have been so long in development and marketing the concept, and yet not have any actual output data. Without data its nothing more than spinning yard art, and thats about all the video shows. Yes it looks neat when moving, but when you consider the average frame rate of video and a rotating object, to the point a rotating object appears still in video, than the demo in the video is not very high RPM, so i doubt it will produce much output. Nice Art. Pete. Sometimes it just works |
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| Drewartturbine Newbie Joined: 09/08/2011 Location: Posts: 30 |
Hi Guys, For those interested in seeing data on turbines output, go to my website and at the bottom of the page http://artturbine.com/relevant-documents/ is a copy of the report by University of Victoria phd student (mechanical engineering) showing his analysis of my output data. My data is logged at around 20 hertz, including wind, torque and turbine rotation speed (at 360 steps per revolution). If someone wants a copy of the raw data, I'd consider emailing it to them. My patents's not secret, patents by definition aren't secret. If anyone want to see it, just google Andrew Rokeby-Thomas and cross flow turbine. How it works is educated guesswork, driven in large part by watching smoke pass through variations on the turbine, loaded and unloaded. That I'm not willing to share right now. I know that I'm an odd duck, neither fish nor fowl, and that hasn't helped my credibility here. Not quite engineer (amateur or otherwise), not quite business person and sometimes just abrasive. I'm learning.... I'm an introverted exhibitionist, I'm only here to show off really, but I could use a bit of help. I have had a hell of a time with my alternator, in part by being willing to invest heavily in wild guesses which got me a long way in turbine shape iteration, but not so great in alt design. At this point it looks like my alt may be able to match output in very low winds, but in high winds needs about 8x more flux density.... I may have to piggyback some rare earth magnets to up the output. If anyone who knows about the electrical engineering of that sort of thing, and wants to help, I'd be happy to send a copy of the output data I have (amps and volts at 20htz) rotation, and wind in. This is of course with the turbine unloaded, so I can also send a lookup table, showing the expected RPM/TSR. Best Wishes, Drew |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
You don't have anything that's easier to read? What we would need to see are the real world figures. Stick the windmill up in the air, with a anemometer, and record wind speeds along with generated power, ideally at one of more battery voltages. Once you have a range of readings, document it along with the size of the wind turbine. Then we can compare its performance against other windmill types to weigh it up. We don't expect it to have the power output of a HAWT, but your design does have other advantages, like appearance. But without any real figures its not worth considering. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Drewartturbine Newbie Joined: 09/08/2011 Location: Posts: 30 |
Hi Giz, As I've said, my alt hasn't come along the way I wanted, test coils as far as I can figure are showing that I'm not in the ball park for expected Watts out vs power available. Data from a test coil wont' tell you much. I'd also say that as an R&D strategy, unless people have mppt systems, tieing an unknown turbine to an alt is not likely to give good info. Hopefully this winter I'll have it up somewhere public, and my goal is to be able to stream to the web, all the data I'm collecting along with extrapolated TSR Cp etc. We'll see If you did choose to look at the report you'd see that Matt Hall (phd student mech eng), believes that we're reaching at least a Cp of .31. If you look at the SWCC (small wind certification centre) documents around the certification of the Bergy 10kW system, you'll see that it's max Cp (using a power point tracking system) is .31. That's an apples to oranges comparison though, as the Bergy number is .31 generated Watts, whereas mine is .31 shaft power. If we can get the electronics sorted then most likely we'd have a .27 or .28. Unlike the Bergy HAWT, we however have lots of room to optimize our aerodynamics. Best Wishes Drew |
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