Will TMA Wind Blow Away the Competition? (vertical wind generator technology)

PESN.com ^ | 1 Feb 07 | Sterling D. Allan

[ridesthemiles]

There is one of these turbines near the intersection of the I-5 and I-405 in northern San Fernando Valley in California. Been there for years. Most people don't have a clue what it is. I do not know the level of efficiency of it, but if I were to put up wind turbines, this is the type I would look into.

[ridesthemiles]

I pulled up their website. If the photos there indicate the structure, they are much larger than the one I posted about earlier. The one I have seen in SF Valley is about 8 times the size of a telephone pole, and has vertical slits for the air to get in and turn the shaft. I don't know who owns it or what it cost, but it is very unobtrusive.

[Richard-SIA]

How about just down-stream of existing power dams?

Secondary power generation, easily connected to the existing distribution network.

[saganite]

You might have seen a test model. There are several companies working on various types of vertical axis wind generators to include small ones you can install for home energy production.

[Ramcat]

The one I have seen in SF Valley is about 8 times the size of a telephone pole, and has vertical slits for the air to get in and turn the shaft. I don't know who owns it or what it cost, but it is very unobtrusive.

Seems like it would make a great privacy fence?

[Dixie Yooper]

You would have to get them very close to the surface to get John Kerry, he's a windsurfer.

[Uncledave]

Actually, I'm intrigued by VAWT designs -- hope they can find a place in the industry.

[visualops]

That's a good idea.
Speaking of farmers- I glanced over an article about "boutique farming" where farmers are growing more specifically what people request and selling direct to consumer with no middleman. I think they mentioned Massachusetts of all places had a high proportion of direct-to-market farming.

[visualops]

Apparently.

[listenhillary]

Bump

[Robert A Cook PE]

Interesting. Very interesting.

I like the points brought up, and the rather straight-forward presentation of the improvements.

less "hype" in the writeup (after words) generally means more thought in the design (beforehand) = more success in the field (bottom line).

[Robert A Cook PE]

True: The "horizontal" shaft turbines have the shaft (as implied) halfway up the propeller diameter - so the generator is off the ground (on top of the support tower) in a very large housing.

For large power -> large propeller -> very large tower -> very large foundations. Lots of weight up high = large moment arm for vibration, lots of movement, lots of of trouble lifting the replacement parts (hundreds or thousands of pounds of machinery or replacement bearings, bushings, brushes, magnets, etc. up for maintenance. Propeller "wing" maintenance is difficult (these things are the size of a 737 wing, and just about as complex. (Though flaps are much simpler.)

A vertical shaft machine puts the weight of the generator at the bottom. N moment arm, and the generator room is "wlk-in" and low cost. Generator mass is low down, helping to stabilize the weight of the "pole" as well, so the "pole" to the upper bearing is much less complex = much cheaper.

Simple bearing components at the top of the tower (no elctrical generator!) means much easier, and much less, and much cheaper maintenance for does has to go on top.

As you pint out, the wind turbine is closer to the ground, so apparent efficiency is less. BUT - what you can do is use a (relatively cheap) tripod or post to "raise" the bottom of the pole up. You're NOT raising the generator (just using a longer vertical shaft) and your able to use a wide tripod or 4-post support at the bottom to reduce foundation costs. but you've still raised the average height of the vertical turbine 25 - 35 feet. If need be,, these guys seem to think they don't need that extra height. (I disagree, but I don't have their equations for low speed economies. My opinion, as soon as they start needing to sell in low wind (12-15 mph average) environments, they'll start raising the base a bit. It's still much less than a horizontal prop perched with its generator on a high tower.)

No, you can't really put the horizontal shaft generator on the ground and run gears down to it from the hub up above. They simply have failed in use: too much stress and and too expensive for the complex gears and shafts.

[Robert A Cook PE]

the little (almost unnoticed!0 key to their entire scheme is the "pull" of the blades FORWARD as they pass into the wind, combined with the PUSH of the blades BACK (away) from the wind that you'd naturally expect. Naturally, the writer skipped right past this point, but I'll bet it's why they are more efficient at low speeds: no "drag" of the prop against the wind as the blade turns as in a conventional vertical turbine.

A sailing boat's sail do the same thing: much of the sail's pressure (forward) is from the suction of the wind passing in front of the curved sail when the boat is sailing at an angle from the wind.

That's why "wind directly astern" is not the fastest direction of sailing for anything but a square-rigged single masted, single sail boat.

[saganite]

I guess I passed over that point too but I've been reading about these folks for a couple of years and that fact is mentioned prominently in all their press releases. Guess it didn't seem new or exciting given my familiarity.

[neverdem]

thanks, bfl

[syriacus]

Thanks for posting this. I have a feeling that the appearance of wind-powered generators will change quite a bit, as the idea catches on.