Wind Turbine - 3 Blade Horizontal Or Vertical Squirrel Cage?

Yes , the three blade has proven in it's time with small wind technologie. If applied with new emerging combining structure desgins ,heat engine technologies, tornado vortec,Commanly know as Renewable thermal transfure systems.

This is research from around the globe in sperate stages of development, Now combining them into 1 structure for the most cost effective structure that has 5 sizes & larger structures can be inside large housing structures as a renewable urban development.

Get the facts and them lets talk about how it works from nature for a better environment.

All 1 word renewablethermalwindpower.com

This is a public education awearness site.

All good thhought went to all this thread, Now lets think together to make it happen as a world 1 community at a time.

A number of people have built the equivalent of the "squirrel" cage on a vertical axis. They seem to function reasonably well on small scales. The problem is, one needs a very large area cross section perpendicular to the air flow direction to maximize energy capture. A squirrel cage big enough to compete with the "3-bladed monsters" would be an even bigger monstrosity...

Mounting the squirrel cage with the axis horizontal (parallel to the direction of the wind flow) would lose a lot of energy in turning the air flow 90º off axis.

I am confused by your statement: "Mounting the squirrel cage with the axis horizontal (parallel to the direction of the wind flow) would lose a lot of energy in turning the air flow 90º off axis."

When I draw a picture of a 'bladed windmill', and a vertical or horizontal axis 'squirrel cage', and I try to represent the wind by a series of arrows parallel to the ground there is NO mechanical difference in the manner in which any of them are struck by the 'river of wind'. From where are you deriving the loss of energy? A vertical axis 'squirrel cage' would be easier to reduce frictional losses, as I envision a design, because it would be easier to implement near frictionless magnetic bearings (Though I am sure it could be done horizontally as well). Other than that, I see no mechanism for a "loss of energy".

A vertical axis squirrel cage does not require a change of direction in the wind. If you lay it down so that the rotational axis is horizontal (parallel to the wind direction), then the air will have to turn 90º to pass through the blade openings...

Oh. When I picture a design in my head of a wind device, I just assume that it is going to be designed in such away that it will always be facing the wind. After all that is its purpose - to catch the wind.

Then wouldn't it also have to turn 90 degrees if the axis were vertical?

Being vertical no matter what direction the wind approaches the device it will strike a concave blade, and cause it to turn.

And it'll strike the opposite convex blade and urge it to stop.

And yet, they manage to work.

So does a paddlewheel boat. Lets look at small offgrid residential.

Sticking to a productive thread topic, why do you believe that a person should use a ground mount vert versus a tower mounted mill, say a SW Air X that both produce the same amount of power annually. (this is a very difficult number to calculate, and no vert mills that I could find actually went past the theoretical gen specs to project power production. This is the primary way that people get misled, (for any wind power)

I have an Air X, and I don't work there. I paid about 1100 for materials, including a concrete pad, tilt down base with welded rebar cage lugs (for the concrete footer)that I built myself, mill Air X 12V (500 watts max at 29 MPH windspeed, which is meaningless), 90 feet #6 conductor run (270 total wire feet) and a 34 foot tower. I built and installed all myself. I did extensive research, because I, like you, want to know what the best options are. For my site, the choice was clear to me, as the vert mills I looked at would have had very poor performance because of a building and trees. (but I inferred that, as I could not really find production data) They also have an installed base, with statistical data. My production is in line with my expectations, although primarily, it functions in float mode.

It is rated for 110 MPH winds, it looks absolutely bullet proof sand cast aluminum. I got the longer wider blade option, to harvest lower speed winds. My question is, should I have use a vert mill?

PFR-

You bring up a major limitation of the ground-mounted VAWT's, which is lack of access to the wind due to interference with buildings and trees. It is also interesting to note that nearly all, if not all, of the VAWT's one reads about are the product of DIYers, not generally those with solid commercial interests. This also contributes to that lack of real data regarding actual power production (I do not mean to suggest that these developers are intentionally misleading people- most likely they do not have the resources/knowledge to conduct long-term tests that could generate such information).

Sounds like your tower is a bit high- most of what I have done has been installed on 20 foot towers, but that also depends on what sort of interference one has around the site. For your "float" application, I would say that you have made the right choice. You did not mention the currency for the investment, but $1100 would be a very, very good price to pay for this sort of installation...I doubt you would have been happy with the VAWT in your circumstance. Which is not to say that your choices would necessarily be the appropriate ones for other circumstances.

I'm sure I had (self performed) at least $4000 USD in installation and design, I was quoting raw materials with no markup. I think I could have contracted turnkey for less than $4500. I was not trying to lowball the project cost. I hate it when people don't include labor costs, design, permitting, overhead, profit in a quote. Sorry about that.

How can a tower be too high? I seriously would have put it at 56 feet, but it was almost 4 grand extra in concrete, bigger poles, guide cables, etc. My research says the mill would have easily doubled output. Not enough ROI for a tiny mill, but for a larger one, higher is better, no?

In my opinion, ALL towers are too high. I suffer from vertigo, and more than 2 feet above solid ground creates serious problems for me. In fact, just looking up to see if the thing is turning can pose a serious threat to my personal vertical stability! Geography dictates what is the appropriate height for a tower, not my vertigo. And, with wind, the higher the better (less ground effect).

I am still impressed with your numbers- the last system I put in (on, if memory serves, an 18 foot tower), was about three times your materials and labor costs combined (including, of course, my not-insubstantial engineering fees, but not including the cost of locally fabricating new fiberglass blades, since the original Chinese blades tended to fail in a light breeze- and after the second "warranty" replacement, we decided to have someone who knew how to work fiberglass build the third set).

you are correct. I looked up efficiency and used as fans, squirrel cage approaches 90% while 2 or 3 blade fan is about 50%. I don't know if there is any correlation when the use is reversed. It was only a thought. How do we close a thread? I'm done.

I personally see a vertical type, a Savonius (or VAWT) as the best types of DIY windmill to build. Probably not as efficient as other types, but simpler to construct.They do not need to be turned to the wind direction, which is of course, part of the simplification.....

It is also easy to stop running (an impotant point in or just prior to a storm) by simply covering up with a big sack or large strong plastic bags or similar....the efficiency is lost and it will not turn well....nor overspeed!

There are many good videos on YouTube of this type as well....Search using just the words "Savonius" or "VAWT".

For example:-

http://www.youtube.com/watch?v=bJVYK_GI0lY

http://www.youtube.com/watch?v=09-om1DGvO8

Best of luck.

A squirrel cage on an horizontal plane would always be my first choice for a wind generator,although wave power would be my absolute choice,anyway a horizontal impeller with a shaft down to a generator at ground level seems to be the most economical design, once erected the generator can be maintained easily,there would be less weight up at high level & no matter which way the wind blows the impeller is the right way round, also if the cage were made longer it could be a smaller diameter. You see lots of small versions of this on motor homes over here to charge batteries & seem to work quietly & efficiently. Another advantage with the design would be to have a centrifugal brake on the down shaft as an emergency brake, you could also fit a retarder to the shaft to regulate the speed.

Bazzer

Hello All

I am also a fram boy with many questions for my Dad was how & what makes the wind? He allways replied,: when you understand the question only then can you use wisdom to get the answer.

The answer is so simple we over look whats happing around us each day that we don't think of. The old school farm wind mills had many fins to catch more wind, now if placed a cone shape nozzel small end pointing at the finns, then the fins would spin faster.

New school is half blind to the facts of combining the best of wind and structure desgins for updrafts with jet stile finns & hydraulics to aid in speed control & backup accumlators for on demand power. Emeraging urban research & development is underway, Its' called Renewable (Thermal)=wind power the energy power source.

The public awearness Education site is all 1 word renewablethermalwindpower.com

This system is not for sale its free to any community which supports it from its' inventor for control from big company's .

GET INVOLVED WITH OUR PLANETS' ENVIRONMENT.

The strength of the wind is reliant on the number of women and politicians in the vicinity grasshopper.

Bazzer

There is simply no question as to why the wind power market, both commercial and residential, is dominated by horizontal shaft bladed mills. Elevation. The quality and quantity of potential power is greater as you gain elevation, with far less (efficiency reducing and equipment damaging) turbulence. A second and less apparent reason is that dollar per watt wind project costs (based on watts produced annually, not equipment ratings) are less.

There have been a few references to the effective impact of wind direction change. I understand the effort to increase reliability, by reducing moving parts. But I have not seen any reference siting reduced efficiency as the reason to avoid letting a mill either electronically or, most commonly with residential mills, mechanically, track the wind direction. Is that what the posters are implying, or is there another reason?

The multi-blade windmills that are ubiquitous across the US midwest are built for torque and are typically used to pump water. They'll run much slower than the 3-blade electric generator units. They will also furl (turn away from the wind so as not to spin too fast) at lower maximum wind speeds because of their mass.

It's easier to make a generator that takes advantage of the speed of the 3-blades. It's not so easy to efficiently generate electricity using the slower multi-blade windmills.

Indeed, it's really cool that Aermotor still manufactures these windmills, but they even warn on their website that their windmills aren't good for generating electricity.

I guess I'll have to say it again. All the problems of overspeeding and/or braking a HAWT , and turbulence, too, go away if you build it with flexible blades with variable twist. Each section of the blade is controlled (think trim tab) by the lift generated (differential pressure, top to bottom of the airfoil), so the blade never stalls, regardless of rotational speed, and the speed and torque can be controlled by the designated lift. (the same concept can be applied to helicopter rotors)

" If 3 blade fan(e)s were efficient, they would be used for central air movers instead of the small squirrel cage".

Really?

Why are we rehashing all this BS?

See the very excellent comment of 'tcmtech' at #2

The 'squirrel cages' have a usage, but very specific to certain applications.

Stu.

A man by the name of Jacobs developed the three blade system, you might also know him from the development of the sacrificial anode.

The three blade system gives the most efficient (wind speed vrs tip speed) performance. He also proved that three blades were optimum.

A wind turbine is the inverse of the airplane propeller. Two, three, and four blades are common on airplanes, because they are efficient. I can't recall seeing an airplane with a squirrel cage propeller. Although such might work in a proper duct, like a jet engine, I doubt it would work as well as a three blade propeller with a large disc area.

I thought the whole idea of a well designed propeller HAWT is so that you can attain rotor speed greater than the wind speed through lift and not drag half the blades through the wind?

Wouldn't the common design of squirrel cage vanes act like a VAWT and not produce lift and also drag the oncoming vanes(90 deg to oncoming wind) in effect slowing it so that it could never attain the actual speed of the wind let alone faster than the wind?

The only way I could possibly see a horizontal squirrel cage going as fast as the wind speed would be to put a rotatable wind scoop atop a tower and feed a, horizontal to wind direction, squirrel cage rotor from the center of the angled vanes out like a turbine pump. That way every vane works at the same time and doesn't drag the oncoming wind like a typical HAWT. I guess the squirrel cage rotor would be a HAWT at that point wouldn't it? Is that what Satcom is saying?

If the vanes are shaped correctly, they might even provide a lifting action to spin faster than the wind speed. Perhaps tapered wind funneling to the blades might work in that aspect too.

I don't know if I am right on any this, I'm not an expert and I didn't say this would work or I had proved it would. It was just an idea so feel free to shoot holes but, I would like to ask that those eager to prove that they think they know more than others not to respond unless they can bring and show the personally verified proof before saying it won't work. This forum should be about answering questions of the less knowledgeable by those "in the know" not those who merely "think they are in the know" based upon their own conjecture.

Sorry for the above paragraph, it is just that I have seen a lot of people on forums like this one say things as fact with math formula and "what someone else said they proved" without any personally proven proof and, years later, someone proves them wrong. By then, nobody remembers what they said years before and people still take everything they say as gold. Well, I remember them and a lot of people were stopped from doing the very thing that worked for several years because some Guru in a forum told them it wouldn't work! nuff said ;) Again, sorry for the topic unrelated paragraph after my related questions and statements.

Its good that some have some clue of the possibliities when combining bifferant techs' into 1 structure , Great JOB. Now lets work together spreading the word it is possible to get done right and effisently.

Join in on face book kenny Magers

What makes you think that the whole idea of a well designed HAWT was to attain prop speed greater than the wind speed. (I'm not really sure what the compared units might be, unless you mean tip speed to windspeed) I always thought the whole idea of any mill is to harvest the greatest % of the (Betz limited) energy possible. Increasing the speed of the rotor (shaft) might even reduce the efficiency, mightn't it? You can google betz limit.

I am not in the know, however, I would like to know more about your theory.

A properly designed squirrel cage will go faster than the wind because the trapped air ha tos find a way out of the cage and so pushes twice, not double tho.

Torque developed at the tips of the 3 bladed types is why they are used. To get that kind of torque out of a squirrel cage it would be too big and expensive.

Squirrel cages have much lower start up wind velocity requirements.

There are many companies that have been making them for decades for the sailing industry. None of it is new technology.

Easiest thing is just to buy a used one off some sailor who is tired of cruising about.

Thirty-two years ago in central Washington State near Ellensburg there was a vertical windmill with two vanes on it something like a spiral. I would assume it functioned something like a squirrelcage. It has since disappeared and I don't know when.

I worked a bit on this when at the lazy B ranch (Boeing Aerospace). We had all kind of problems with the gearbox, but when finished it set a buncha (< technical term) records.

Research I did a while back uncovered the statistic that for the Vesta turbines off shore in the Netherlands. the average life expectancy of an offshore wind turbine was on the order of 18 months. Main failure- the gear box. It was easier or cheaper to replace the entire unit than to replace only the gear box. This resulted in a flood of "refurbished" Vesta turbines being offered at amazingly good prices in places like Panama...

I suspect they have fixed this problem by now.

The dynamics of the main shaft is the problem. When the blades shadow the support pole there is a change in loading of the shaft and bearings. The support structure is ASTM A709 and the life of the support structure is approx 20 years, which , unfortunately, is the payback time.

Check out this rooftop wind turbine: http://www.popsci.com/gadgets/article/2011-09/personal-turbine-makes-your-rooftop-wind-farm