Re: Vertical Axis Wind Turbine / Generator

[MadTripper]

I've been reading about them lately. There is also a helical style horizontal unit that is pretty nice. Here is a link to a homemade unit like the one you are looking at.

http://www.popsci.com/diy/article/2007-07/going-wind

Tripper

[machinemaker]

a great DIY wind site is www.windstuffnow.com. they have a couple of vertical axis turbines you can make.
kent

[AlchemyAcres]

Has anyone heard of this type of generator?
http://www.verticalwindgenerator.com/
Sounds good.


Cool, however, it's important to strongly question anyone who suggests that a wind genny mounted on your roof or at 35 feet is going to produce energy in a efficient way and give a good return on your investment. The 2 most important considerations when generating electric from the wind are speed and height, vertical axis machines have a problem with both.
It's even more important to question those who are purposely vague!

"Produce 1KW and up"

Yeah, ok, sounds cool....now, is that a KW in a day, a week or a year? LOL....and at what wind speed??

If you want to get the most bang for your buck and maybe even make your own turbine...horizontal axis is the way to go...the best place to start is here...

http://www.scoraigwind.com/

If you're considering building your own turbine, his book is priceless.

~Martin :)

[MadTripper]

Most of the benefits from these types of windmills are reduced noise levels and fewer parts to maintain. Additionally, they are helpful un large cities where updrafts are present. (Check Chicago out as they are supposedly being installed left and right there) The helical style, which I've only seen on a horizontal axis, can handle wind from any direction without having to turn and face the oncoming wind current. One other supposed bonus is that they do not kill birds. Personally, I think that takes a lot of the fun away but who am I to judge.

I'd like to try and build a helical style just to monitor its output at my place.

Tripper

[AlchemyAcres]

No doubt they can be made to work...they're just not anywhere near as efficient as a HAWT considering the same swept area....tip speed ratio is lower...drag is a problem because there's always at least one blade spinning back into the wind.
VAWTs must be built almost twice as big as HAWTs in order to generate the same amount of electric.
They're almost always more costly to build.
Some VAWTs are not easily self-starting...
They're almost always heavier...so require heftier towers and such.
Probably the biggest issue with VAWTS is braking in high winds....it's easy and simple to build furling into a HAWT...not so with a VAWT....some type of braking is needed so the thing doesn't fly apart or burn out the coils when it's super windy.

Having said all that...VAWTS have a place....especially in high-torque mechanical situations....

This has got to be one of the neatest designs....relatively simple.....fairly easy to build...light in weight...easily could be made portable...very versatile...
I can't imagine it's all that quiet, however.....

I'm tempted to order his plans.....

http://www.greenwindmill.com/


~Martin :)

[chrisser]

I've often wondered if a VAWT could have its efficiency improved by enclosing the blades inside a slotted "barrel", perhaps *tied to a vane. *That way, the blades coming into the wind would be covered from the wind.

What I had in mind was the sides of the "barrel" subdivided into six equal parts - three would be open (the slots) and three would be covered with light metal (to cover the oncoming vanes). *At any given time, the wind would "see"roughly half the barrel covered (where the blades were coming towards it, and half open (where the blades were catching the wind). *After the wind hit the blades it would vent out the back slots.

Not sure if it would be worth the complexity though, assuming it would even work.

[AlchemyAcres]

Probably the best (?) way to improve the efficiency of any turbine is counter rotation...but again...it's very complex...basically one rotor spins one way with the magnets and another rotor spins the other way with the coils...upping the efficiency considerably for any given swept area....and again...HAWTs are more suited.
IIt could certainly be done with a couple VAWTs though, one on top of the other. :)

http://www.earthtoys.com/emagazine.php?issue_number=07.04.01&article=contra

~Martin :)

[chrisser]

That counter-rotation concept is pretty cool. IIRC, they said arond 30% more power and elimination of a lot of the bending moment forces.

That sure seems worth the extra complication. I'm surprised more homebuilders haven't tried it.

Did a quick Google search and couldn't find any examples other than large-scale turbine studies.