Why aren't there any VAWT's on this board??

[doop]

Hi,

I've just stumbled across this board and was interested to read all about the construction of the resin coated stators and magnet arrangements.

(Source: http://www.otherpower.com/stator.shtml)

I'm interested though why all the examples are using horizontal axis - propeller style blades - the traditional style of windmill.

I've seen lots of videos on youtube or vertical axis wind generators and seen many models - particularly this style:

http://i.treehugger.com/files/th_images/mw1100.jpg

And was wondering why i can't seem to find any examples of this style being used (or for that matter even tested) ?

It seems to me that the diy style rotors many have allready build on here would be a perfect start to building one of these and showing a side by side comparison of Vertical Vs Horizontal and the associated power outputs Vs Wind speed.

A quick search and nothing seems to have come up.

Could someone please point me in the direction of anyone that has used the above mentioned style of rotor/stator and build a similar looking vertical wind generator or maybe fill me in to why this isn't being done??

Thanks.

It has been determined this is a TROLL.

Therefore this thread is CLOSED

[doop]

My mistake there seems to be one thread I've found but it seems to have died...

Thread: http://www.fieldlines.com/story/2008/6/1/213436/3632

Image: http://www.otherpower.com/images/scimages/10233/IMGP2380post.jpg

Has anyone else built/tested something similar???

[Savonius Man]

THIS IS PRACTICAL

This device was built in 3 hours using two telephone poles, 2x6 lumber, and 6 sheets of roofing metal.  The rotors are 7 feet tall and the affective width of the rotors is 5 feet.  The top horizontal spar is 15 feet off of the ground. It has been turning for the past 8 months now with no problem. This device has pushed 1kW at 25 mph Winds.

I don't think Savonius designs are as ineffective as everyone seems to say.  A major benefit is that they can be built quickly, and cost next to nothing.  That said, even though they are less efficient, you just put another 10 dollars into your investment and make the whole thing 20% taller.

The generator can be mounted at the base for ease of maintenance, and it never moves, so you don't have to worry about untangling you cords.  It performs very well in high winds, and is self governing.  No welding required.  I challenge you to make a 1kW horizontal turbine without a welder, for under 150$, and only 3 hours of labor.

[zap]

Pretty much what the ADMIN said... they're not too practical and basically... most of the work on this site has so far, been in the direction of the hawt.

As Savonius Man shows, they can be made to work.

What exactly did you search?  Did you use?

"Search the board" and "Google search the board" can, and usually do give different results.

Using the "Google search the board" link and using just "vawt" I got over 500 hits and the very first hit has this as the first sentence: "The 6 coil single phase stator failed to produce a satisfactory output under real life wind conditions."

A good clue as to why vawts are difficult.

Good luck

[TomW]

Please post some pics of the electric generating parts.

Nobody argues they don't spin.

Your cable doesn't seem to attach to anything?

Ed Lenz has created some beautifully functional VAWTs but they are not simple machines he has skills few posses. His stuff is very good. Try a search for posts by windstuffnow on this board.

Tom

[boB]

I saw  Mariah Windspire actually charging batteries at around 750 Watts not long ago. AC coupled into an outback inverter for conversion from AC to DC.  It looked like it was working pretty well actually... Class 6 wind site, but it didn't seem all that windy when I saw it.

It's been in service a couple of months maybe.  I hear that it now has some kind of mechanical problem (that will be fixed), that was somehow a result of braking.  It brakes, (pretty well I though), but was a bit too hard on it as I understand.  It's an electrical brake.

If a VAWT is going to be placed close to the ground (not up 100 feet), then it must have a large swept/capture area because the amount of wind is just not enough to be practical.  I think that is why those little spinning garden art thingies don't work.  WAY too small to be practical.  I don't care for their look because they just look like a spinning air vent to me.  Would that shape of Savonius really work that well anyway ?

So, VAWT's CAN evidently work...  Just not nearly as well as an HAWT installed properly I'm afraid.

boB

[Savonius Man]

I'm sorry I don't have any pictures with the generator mounted to that device. I had enough trouble getting the rotor mounted that day, and I came back later to mount the generator, but didn't have my camera. Here are some shots of a smaller VAWT I built.  600 watts at 25 mph winds.  the only shot I have of the generator was after dark.

I've decided that the only way I can prove to you HAWT naysayers that VAWTs are feasable is to create a continuous video that shows my turbine spinning, anemometer measurements, current readings, and battery bank all in one shot.  I'll post on youtube and give you guys the link.

Bob, you are right, for the size, HAWTs just plain work better than VAWTs.  But that's not what I am after.  I'm only looking at cost in materials, labor and maintenance.  Like I said earlier:  I challenge you to make a 1kw HAWT that requires no welding, in only 3 hours, and costs less than 150$.  My Vawts may be less efficient, and have less wind available so close to the ground, but its really easy and cheep to make them a couple feet taller.  I'm going to start a VAWT wind farm in colorado.  I don't care what they look like, all I care is that they are cheep, fast, and easy.  

[ghurd]

Most VAWTs try to solve probles that do not exist (twisting wires, etc)

or get power where there isn't any wind (wooded back yard, etc).

Speed makes cheap efficient power, and speed is easy with a HAWT (even a pretty crappy one).

VAWTs are only easier until you try to build one.  Building one that makes power efficiently is even harder!

Fairly simple to slap together a working HAWT that outperforms a similar VAWT.

G-

[Savonius Man]

I would never mount a VAWT in a backyard.  Only adjacent to open fields as all of my pictures show.  It is very easy to make a VAWT, even easier than a HAWT because you don't need a welder, and you can pick up all of the materials at the Home Depot.  The primary deterrent for most people who try jumping into this craft, is that they need to find a skilled welder to make their ideas fly. I can build a 1kw VAWT and fiberglass generator (using my molds) in about 8 hours, using a hammer, drill, and two wrenches.  Have you ever made a HAWT without a welder?

[ghurd]

How about 65W in my side yard, in an hour, mostly from trash, for a Grand Total cost of about $2.50 for the bridge rectifiers?

I was a welder for a while back in the '80s, but I do not have one.

G-

[Savonius Man]

HAHA.  I stand corrected.  How long has that been turning for?  You would need 25 kwH at 10 cents per hour to pay that back.  Thats about 16 days of constant 65 watt production.  Nice disign.  Is that a tread mill motor?

[electrondady1]

my vertical is in the front yard .

I'm not ashamed of it.

it only sweeps 4 sq. ft.

i don't expect much from it and it produces a small amount of juice almost constantly.

it's an offset layout  the same as my original "little erma" mill

 but the alternator is based on what i have learned here.

it's a dual rotor axial flux

it's  single phase with 16 poles.

massive turns , massive resistance

very few amps

there's another coming  , almost like it,(a better design) on my bench.

the alternator knowledge around here is real

the people are helpful.

once you understand a bit about how an alternator works you can adjust the parameters to get a useful voltage within the rpm range of your mill.  

[FishbonzWV]

Hello SV Man,

No welder used here.

Purchased mags,rectifiers,JB KWIK, and some nuts and bolts.





All the rest was scrounged.

doop,

Have you seen this site?

http://www.vawts.net/index.spark?forumID=125317&p=1

Bonz

[spinningmagnets]

Dear doop, As previous posters has said, if you use the "Goolgle search the board" button, you will find a treasure trove of information from actual projects.

The sad fact is, that wind is much better in just about every possible site if you mount a wind-turbine at a higher elevation. Your project site may vary, but most sites seem to list 60-feet-high as the place where "serious" wind can be harvested.

VAWT's have a higher torque, but slower RPM's. This is good during rare wind-storms that would damage a HAWT, as most of the wind goes around the VAWT, so its top RPM is inherently limited in the shape.

However, the lower RPM's mean a gear-up of some type must be used to speed-up the alternator. Though HAWT's must furl-away during rare high winds, they are direct drive, and a well-designed unit will provide years of reliable service (I'm told)

Wind is a fickle mistress, and you may find her affections to be inconsistent and widely varying in depth of passion from day to day. A VAWT may be best suited to generating and storing air-pressure. If employing a large reservoir and being rarely used, air-tools can be quite useful.

You can drive a nail with a wrench, just as you can generate electricity with a VAWT. However, if you are depending on a VAWT to perform a significant job, you will soon find yourself saving your pennies to buy a larger battery and a significant HAWT that is mounted on a 60' tower.

Why not have both?

[Flux]

The first wind powered devices were VAWTs so they do work. The first things were pure drag devices with a wall or screen to give a preferred direction  of rotation.

Probably the most useful of the vertical axis machines is the Savonius and it performs reasonably well. If you give it a good site and build it big it will work perfectly well but the very low rotational speed means gearing, but it has enough torque to stand gearing reasonably well.

There have been numerous attempts to devise vertical axis lift devices with Darrius being the best known. Musgrove tried to re introduce the idea in the 70's but cyclic stress problems have always been their downfall on large scale machines. Most likely smaller machines work where the stress levels are less of a problem.

Again they need good wind and the common belief that they work in poor turbulent conditions is likely to be the biggest reason for their low credibility. ( no turbine works under those conditions.

The other class of vertical machines that adjust the vane angle ( cycloturbines/gyromills) have promised the earth but again have not really delivered.

They can and do work but although the swept areas are comparable to a HAWT the volume they take up is large and once you start raising them up into clean air they loose most of the simple virtues.

It may be a case of personal preference, If you can't or won't weld and are happy with poles and bits of wood and metal sheet then by all means do it that way and if you build it big and in a good site it may do all you want.

The only attempt that I ever had at a vertical machine ( small Musgrove type H mill) was a total failure, there is probably a size below which it will not supply its own losses. I have no desire to try anything else and most of other peoples attempts I have seen have been such abominations that I am not surprised that they don't work.

If you are prepared to engineer these things properly then they will work to some extent. The Savonious is reasonably self governing and that is a good feature but it needs to be big with its low Cp. Lift type machines present starting problems and more serious governing problems and are a bigger challenge, then add the problems of getting them up in the air clear of turbulence. Not for me I am afraid and I don't like the look of them so they have no chance with me.

Flux

[Ungrounded Lightning Rod]

HAWTs are simple structures (three moving parts plus a twisting wire or slip-ring arrangement).  They easily achieve high efficiencies - both a close approach to the Betz limit on efficiency of collection of power and the efficiency that really counts:  dollars/watt.  They are easy to locate on a tower, high enough that the wind is much faster than near the ground (with available power increasing with the cube of wind speed).  They have some problems with speed regulation that must be handled properly to keep them from self-destructing in storms - but that is well understood.  Their wind loading vs rotational position is nearly constant.

VAWTs are even simpler (one moving part unless a transmission is needed).  Their wind loading cycles with rotational position.

The low-TSR designs have somewhat lower efficiency (about 2/3 of Betz for the Sandia Savonius, less for others) but they're easy to scale up.  They spin slowly enough to have low centrifugal stresses and have shapes that allow them to be strong against both such stresses and wind loading, so they don't necessarily need furling to avoid self-destruction.  They also have a low RPM (unless they're very tall and thin) which makes direct coupling to a generator difficult - raising the cost of the generator or adding cost, complexity, and reliability problems with adding a transmission.

The high TSR designs have serious structural problems due to cyclic stresses and this makes them both short-lived and hazardous.  They usually need furling but are difficult to furl.  To collect enough power they also tend to be wide enough to be low-RPM machines, with the noted disadvantages.

Due to the lower efficiency and resulting larger size, weight, and drag, it's hard to support VAWTs at the heights of high-speed winds.  Siting them low means they must be even larger and requires a site that is essentially flat for a considerable distance in order to provide adequate wind.  Their larger size and low siting can also make them more of an eyesore than a HAWT generating similar power.  This can be an issue with neighbors and zoning.

So for many sites a home-brew HAWT is far more practical than a home-brew VAWT - at least given the current designs of both.  And because HAWTs are getting more attention, their designs are also more debugged at this point.

This website has a number of people who experiment with VAWTs or are interested in discussing them.  (For instance:  I happen to think variants on the Sandia Savonius might be worth a construction attempt.)  But the bulk of the postings here are about HAWTs, as are the vast majority of the successful machines built by the participants.

Postings about VAWTs are welcome.  But expect some skepticism.

[rotornuts]

Ha Ha Ha, I find this post extremely amusing considering this is the first time I've visited the site in about 6 months and only the second visit in about a year.

Doop, I was and still am an advocate of the VAWT. I don't share the disdain for them that the admin and some others do, but I can sympathize with that distain.

Windstuff Ed is the only person that I have seen on this forum who has actually produced a VAWT that is revolutionary and practical. I fully encourage folks to experiment and see if they can come up with a functional design of their own but would like to say that you should be well prepared to understand that the pursuit of a VAWT that is better than a HAWT and just as easy to build can easily border on the free energy fringe thereby upsetting the sensibilities of the people who live here many of which truly live what they talk about.

This forum is geared towards the folks who ask, experiment and build so that they can or can continue to live off grid in an independent and sustainable manner. There is a great deal of noise on the internet and these guys don't want to have their forum for the exchange of practical ideas and projects related to the now lost in a sea of S^&*.

That said the people here also love to see new and interesting projects and ideas tossed around but don't forget they have been here a long time and have seen most of what the average person can dream up come out in a post. Before you start to clutter the airwaves with notions of a revolutionary power generating device please do some research and ask yourself seriously if your idea is going to work and also realize that there have been many an intelligent person here already one of which likely has some experience with what you are thinking.

Search the board. You obviously failed to do so before posting. If you had you would have found a plethora of practical and impractical VAWT examples to keep you buzzing with excitement for months. There is not one single person here who would say that you cannot generate power with a VAWT but most would rightly say that considering the level of refinement and the ease of the home brew HAWT why would you bother other than to satisfy a passing curiosity.

If you do decide to venture into the world of VAWT's I encourage you to do so only if you are extremely stubborn, persistent and talented. The folks around here would appreciate if you refrain from posting too much until you have thoroughly researched your intentions and done some experimentation. Pictures and power generation results are soothing to most and avoid proclamations of having created a world changing wind generator that prove the HAWT people as simpletons as that will never fly. If your contraption has more than a couple moving parts please understand you have likely already failed. Hinges count for automatic disqualification, please don't go there.

I have shared on this forum many a stupid idea and eventually quit posting here because I wasn't producing any results. I had lots of ideas, some of which I'd like to dust off some day soon and resume experimenting with. The people here were very tolerant of my lunacy and even encouraged it to a degree.

I, to my knowledge, am the only person here to have build a single blade windmill other than those who where inspired by my attempts. To top it off my blade was wide where it should have been narrow and thin where it should have been wide. I still think it will work. I also tried quite a few variations of VAWT's and firmly believe that they have place in the wind generation world but improving on the best of current tech. is not easy. When I say not easy I don't mean to say that the simpletons who have tried to date have overlooked the fact that all they had to do was flip the domahiky over here use some zero friction bearings, add an instantaneously inflating and deflating balloon mounted to a hinged flapper to catch the wind, change the angle of attack, add some extra twist and shield the upwind side as if to play peekaboo with the windmill. I mean to say that your trying to one up some very bright people.

Enjoy,

Mike

[wooferhound]

A generator for a VAWT is very much larger than a generator for a HAWT. The picture that you are showing is not showing a generator which should be very obvious.

[wooferhound]

""Have you ever made a HAWT without a welder?""

Here is my HAWT made without a welder

http://www.fieldlines.com/story/2004/4/4/164552/3003

[TomW]

Woof;

So many misconceptions being regurgitated here it is just too much energy to refute them all.

Perhaps a case of "better to be silent and thought of as a fool than to open your mouth and remove all doubt".

Maybe the KW it produces is just theoretical or the poster thinks we are dumb enough to just believe there is a see thru alternator supplying power through the aether?

If being "nice" means we have to swallow that then I proudly choose to be "not nice".

Anyway lets put these energies into helping someone get a functional unit flying and making power.

Semi topical to the forum:

I been trying to balance my 8 footers prop on the head but the wind is just enough to drive it at about 20 RPM for a half hour before it settles. Finally gave up despite needing the power lately.

The little 2 meter Zubbly built conversion is churning out a steady 5 to 10 amps [125 to 250 watts] up at 60 feet. Thats real world real electrons fed through actual wires into actual batteries to eventually fed through a real inverter into real appliances.

Thats what we are about here.

Tom

[jonas302]

IT would be really nice to get a full write up on your turbine posted I dont look at anything on u- tube so some nice still shots and constuction details would be great  

That is probly the best location I have seen a vawt in most are inside a fenced in back yard

No challenges or worthless bickering just a technical write up with lots of data

[Savonius Man]

Flux Ungroundable and RotorNuts,

Thank you all for the positive replies.  I should have known better than to post some pictures of my Savonius designs without catching some guff.  In the begining, I learned how to make generators from otherpower.com, then I waited 4 years through tinkering, experimentation, and finally application before coming to this site to post.  Now I'm regretting not taking more pictures of my 15' savonius WITH the generator on it.  Though I let that device free wheel most of the time, and I haven't even gone to the site in 5 months, the times that I did have a generator mounted to it proved the device to be functional.  It pushed 50+ volts and 20 amps = 1kW into 4 batteries at 25 mph winds.  Unfortunately, probably because I am new here, no one is going to believe me.  

That is why I have decided to drive an hour back out to the site and mount one of my newer generators to it and get some good video.  I think the only way you guys are going to believe that a 1kW device can be made in 3 hours for about 150$, is if I make a video that shows the turbine turning, the anemometer readings, the current metering, and the battery bank all in one continuous shot.  But then the nay sayers will probably argue that it took more than 3 hours to build, and I'm not going to post a 3 hour video.  

You have all brought up really valid points as to why most people prefer the HAWT designs.  They have been perfected, they have less moving parts, they are higher up and harness a cubicaly larger amount of wind power, they turn much faster and thus create excellent charging voltage, and they are attractively elegant in their simplicity.  

Unfortunately, I don't believe that any of these factors are important. I live in the USA where money drives everything.  I am starting an LLC to manufacture Savonius turbines for Iowans, and in this state of economy, my clients only look at dollar signs. The costs of any turbine are driven by: Materials, Labor, and Maintenance. Pressure treated lumber is cheep, and scrap roofing metal is widely available for free. Ground based turbines do not harness the cubically larger available power that a HAWT sees up on a pole, but I can make them have a much bigger area without a large increase in cost or labor.  I'm sure that one of the major HAWT costs is the tower, and as you increase the swept area of your blades, the tower cost increases exponentially. My employees also do not know how to weld, and this isn't an issue.  I have built a 1kW savonius, in only 3 hours, for about 150$ that has lasted over 1 year with no maintenance.  

I came to this site for your advice.  I want your feedback on my designs, and I know you guys are a very smart breed, so I appreciate your criticism, But... I really want your help.  If all you can say is: "this guy is full of sh**", or "VAWTs just don't work"  maybe I should go somewhere else.  Sorry for the long post (it may be my last)

[deloiter]

Savonius Man, Where in Iowa are you located? Would you send me an email so we can correspond directly please? Keith (Winey101<at>aol<dot>com)

[electrondady1]

http://www.vawts.net/index.spark?forumID=125317&p=1

doop,savonius man

if you want to talk about vawt's check out the above link

[wooferhound]

Practically no one here has made any power with a VAWT on this forum or they would have claimed the $100.oo prize.

http://www.fieldlines.com/story/2007/10/10/52711/090

Also, no one is disputing your claim of constructing a VAWT or that you can do it economically. We are disputing that you are making usable power with it . . .

 

[wdyasq]

Woof,

The friendly calculator on the IRC channel comes up with this:

2717.6 watts possible from 6.6 ft dia prop (34.2 sq ft) in 25 mph wind (density of 1.225000) 434.8 watts output assuming generator is 80% efficient and Cp of 0.20

Savoniousman is at about twice anyone else has done with a HAWT No further comment ...

Ron

[birdhouse]

could he be posting open volt results???

[windstuffnow]

Ron, he's probably not that far off ... He said the turbine was 15 ft, didn't catch the diameter but assuming it was at or around 4ft  ( 60 sq ft ) with a Cp of .2 I get 952 watts.  

The 4.5 x 8 ft Lenz2 will do around 800 watts in the same wind and will hit 1kw at about a 28 mph wind.  

20% might be a bit of a stretch for a savonius and there may be some discrepancies in wind speed but I don't think he's that far off.

In defense of the poor lowly VAWT's...  I happen to like both, HAWT's and VAWT's, and each have their place.  

.

[Savonius Man]

Like I said, its been a while since I've been out there, and it is quite a ways away. It could be that the scoops were 8' tall and the affective rotor width was 6'.  I remember that the top spar was at 15' because I measured it with the tape, and the bottom horizontal spar was at about 4' because it was just above my hip. Looking at the picture I think the scoops were 8' tall.  Thats a standard length for sheet roofing metal.  I don't believe I trimmed those rotors down either.

Given an 6x8 = 48 sqft area (4.459 m2), air density 1.225 kg/m3, Cp of 0.3 (85% lower than a HAWT) velocity of 27 mph (12.069 m/s), 80% efficient generator and bearings, 90% efficient roller chain drive, that would be:

Available wind power(watts) = (0.5)(1.225)(4.459)(12.069)^3 = 4801.3watts

Collected Power(watts)=(0.5)(1.225)(4.459)(12.069)^3(0.3)(0.(0.9)=1037watts

That would take an 8' diameter HAWT rotor to get the same area. How long does it take to make one of those?  

[SparWeb]

Has nobody claimed that yet?

I haven't seen a posting from Volvo Farmer for a while, in fact.  Could he be withholding his worthy contributions until a contender VAWT turns up?

[FishbonzWV]

Don't you just love it when someone posts a thread with a question and then never responds back!

[Savonius Man]

Seriously, How long does it take to make an 8' rotor?  or three 4' blades?  I've never tried.  I assume there is a lot of chisel work involved if you're using wood, and a lot of sanding.  Do you just score the top of the blade with a saw, and chip it back?  Or do most of you make them with fiberglass?  Either way I bet most HAWT 1kw turbines have blades that take many hours to perfect, where all I have to do is nail a sheet of metal to a 2x4, and screw that perpendicularly to a 2x6. I've learned to love lag bolts.  Dewalt has a bit that holds a 3/8 lag bolt with a magnet inside, and it makes for much stronger connections that won't vibrate loose like nails will, and it can be done very quickly with a battery powered drill. The metal has a tendency to tear, so I also use 4 sticks of liquid nails for a 4 scoop rotor, and large washers around every screw. Glue tends to take a lot of the vibrations that the rotor faces and dampens the oscillations.  Its best to affix the sheet metal with a grommeted roofing nail. That little piece of rubber really helps.

The Finished rotor, as large as it is, only takes a half an hour if you know what your doing. One hammer, one drill, two wrenches.

[Savonius Man]

Where am I going to find a third party that is skilled enough to take electrical data recordings?  at a site over an hour away? How about this: I go to the site and record the KWH pushed through the grid tie after one month? I just got a new clamp on KWH meter.  I think I could average well over 100watts at any given time, so the KWH/24/30 should be over 100 watts.  I think that qualifies as the same output.  Thats even harder because the winds don't average 20 mph.  Somebody should ask Volvo.