Author Topic: heat from VAWT (Read 4206 times)

natbow · « **on:** March 11, 2008, 10:41:12 AM »

I'm seeking some practical advice.

Been interested in VAWT development for quite a few years. I'm planning to build one since I live at a suitable location where strong coastal winds are the norm.

I want a `bullet-proof,' low-maintenance system that will simply dump heat into insulated water tanks.

(Have even considered a heat churn or some kind of friction drive!)

I'm not too bothered about efficiency.

I'm aiming to build the turbine to handle about a 2Kw output at 14 m/s - but need electrics that won't burn up when a gale comes through.

I definitely want to avoid Batteries and inverters.

What would be the simplest system?

ghurd · « **Reply #1 on:** March 11, 2008, 06:29:38 AM »

Practical, bullet-proof, and VAWT?

Then 2KW?

Nobody claimed Volvo Farmer's prize for a 100W, 100 day life, VAWT. 2KW is bigger.

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

G-

TomW · « **Reply #2 on:** March 11, 2008, 07:10:43 AM »

G-;

Yeah, you can always tell when a half baked, internet inspired question pops in.

Whatever you do, don't tell people the facts.

Maybe a paddle to stir water [heat via friction] or an eddy current heater [heat via electrical current]?

Since VAWTs don't need clean air, maybe he can mount it in his garage to protect it from weather?

Its getting to be more humor than I can handle around here these days.

I guess VF's prize money will be safe in his savings account awhile.

OK, gotta go get control of my laughter before I get a stitch in my side.

Folks will only see the sarcasm and miss the 2 valid methods I included in this comment.

TomW

electrondady1 · « **Reply #3 on:** March 11, 2008, 09:34:56 AM »

something like this ought to do it !

gotwind2 · « **Reply #4 on:** March 11, 2008, 02:11:35 PM »

It could be done.

Build it from mainly wood, and before it sees any wind, light it with a match, it should provide plenty of heat - for a bit.

Sorry couldn't resist it.

feral air · « **Reply #5 on:** March 11, 2008, 02:48:28 PM »

My basic plan for a large vawt....

Make a cement raceway, maybe 6-8' diameter. It doesn't necessarily need to be completely filled, just enough surface area to run some wheels on it.

Make a large carriage and put caster wheels (like these) at each corner. This part needs to carry all the weight so it needs to be somewhat beefy.

In the center of the raceway, put a car wheel sticking up out of the ground. Once it's cemented into place it should look/work like a miniature merry-go-round -- this is the central pivot point so that the vawt doesn't wander off the raceway. This shouldn't carry any weight so set it right the first time - too low is one thing (shim it) and too high is something else.

Set the carriage on the raceway and secure the center hub to the carriage.

Make a massive vawt shape and secure that to the carriage.

The last '' step is kind of up in the air for me. If this step could be solved cheaply and elegantly I think we'd be well on our way to a workable design.

My first thought was that a small wheel could press against the underside of the carriage near the outer edge of the circle. This could give you the gearing you'll need but I'd worry about slippage. The only other idea I had was to use a gearbox off a tractor implement, like a brush hog or similar...if it was a right-angle, maybe it could be used as the central pivot...?

You'd probably need a second gearbox in either case...I dunno, obviously I'm not that far along yet. take it easy

feral air · « **Reply #6 on:** March 11, 2008, 03:00:04 PM »

A paddle wouldn't do much. Heat via electrical current..lol...

Why bother with eddy currents if you have electricity? Just dump into a heating element. :/

take it easy

DanB · « **Reply #7 on:** March 11, 2008, 04:14:32 PM »

actually a 'paddle' in oil or something can be very effective/efficient. There would be no stator losses for one... and all the energy would be converted to mostly useful heat.

Past that though it's a project that's over my head. I don't have much 'practical' advice to offer. VAWT is just the beginning of the problem I can't say much about, then heat w/o batteries etc.

vawtman · « **Reply #8 on:** March 11, 2008, 04:47:49 PM »

Hi Dan

I always thought a battery bank was stupid if all you wanted was heat.After witnessing a 36v battery bank perform in a commercial floor scrubber i'm thinkin differently about it now.

Dump the heat and have ALOT of reserve for down times.The cost bugged me also then but seems worth it.

I love the scrutiny the vawt gets from little caster merry go rounds to vawts spinning in the garage and little people looking at big things.

It's all in fun :>)

Mark

electrondady1 · « **Reply #9 on:** March 11, 2008, 05:56:16 PM »

both danb and daveb are runing 20' hawt units
that's 314 sq. ft.swept area
.
if a vawt is about half as efficient,
it would require twice as much swept area .(without considering elevation)
25'x 25'=625 sq. ft.

so you need to build the thing as big as a house to get in the game.
and if you are willing to do that. then why bother with conventional architecture.
maybe build the house underneath or within it some how.

motoman465 · « **Reply #10 on:** March 11, 2008, 08:11:38 PM »

Here is an interesting experiment from Windstuff Ed about heating water.

http://www.fieldlines.com/story/2007/10/3/195821/664

Todd

feral air · « **Reply #11 on:** March 11, 2008, 08:28:50 PM »

Ok, maybe the paddle idea could work but I don't see it as being a practical idea for the average DIYer.

feral air · « **Reply #12 on:** March 11, 2008, 08:44:58 PM »

And your practical advice is? :p

feral air · « **Reply #13 on:** March 11, 2008, 09:10:37 PM »

"just over 3KW in 'moderate winds'" is not the same as "about a 2Kw output at 14 m/s".

Your main point is valid, don't get me wrong, it will have to be a big vawt - I just don't think it would need to be that big. take it easy

fcfcfc · « **Reply #14 on:** March 12, 2008, 06:28:52 AM »

Hi: His prize will be safe for a while longer......

finnsawyer · « **Reply #15 on:** March 12, 2008, 08:32:08 AM »

"My first thought was that a small wheel could press against the underside of the carriage near the outer edge of the circle."

Have the wheel or a tire press against the inside side of the circle. I doubt if slippage would be that big a deal then. Have you ever seen those Ferris wheels driven by tires? They work rather well. The problem is that the smallest pneumatic tire I've found has a ten inch diameter. Why pneumatic? that allows you to mount the tire rigidly and let the air pressure determine the foot print and degree of contact. You would, of course, get best results with the tire contacting on the inside of a circle rather than the outside. Well, maybe you couldn't make the circle that true and would need some sort of spring loaded mechanism to maintain the contact. But I think it can be a viable idea.

feral air · « **Reply #16 on:** March 12, 2008, 09:56:13 AM »

The wheel wouldn't ride on the outside edge, just near the outside edge. It would sort of look like the inside of a right-angle gearbox; the large gear is the carriage and the small gear the tire/wheel assembly.

Think of the easiest way to do it and that's probably what I was trying to explain.

Oh, I forgot to mention that I saw the caster-carriage idea put to the test the other day on Master Blasters. In the 'The Blasters of Oz' episode. They had a little play house mounted on it and hit the house with a jet engine...hilarity ensues, of course.

take it easy

vawtman · « **Reply #17 on:** March 12, 2008, 04:34:37 PM »

Spin it :>}

electrondady1 · « **Reply #18 on:** March 13, 2008, 08:22:04 AM »

natbow,

in spite of the snide remarks there are members of this forum interested in the same thing you are.

finnsawyer · « **Reply #19 on:** March 13, 2008, 08:25:52 AM »

I understood that. I just don't think it would be the best configuration.

feral air · « **Reply #20 on:** March 13, 2008, 08:59:37 AM »

Ok, I thought you misunderstood me 'cause I didn't explain it very well.

I see the advantages of what you suggest but I don't think it's something I could do as cheaply/easily. I can't seem to make anything round, especially when the radius is measured in feet.

Maybe one of those big round cattle feeders could be cut down and used? That kind of thing is more my speed - if I could get something that was already big and round I think I could do it like you suggest. Any bright ideas? take it easy

electrondady1 · « **Reply #21 on:** March 14, 2008, 07:23:08 AM »

we've done this before .

bury a truck differential in concrete.

weld up a bracket plate that can be bolted to the differential and used to support 2x8"s

use pressure treated 2x8"x12"s like the spokes of a wheel.

build a nice rotating deck.

under the deck , between the joists ,attach a plywood rim.

place the 10" pneumatic wheels finn was talking about under the deck.

attach them to the alternators.

a 10" wheel driven by a 25' "deck" will have a ratio of 30 to one.

the deck "hand rail" does double duty as the vanes of squirrel cage turbine

put a big savonius sunscreen on top.

in this town you need a permit to build a deck.

i think i may need an engineer to sign off on on this one.

finnsawyer · « **Reply #22 on:** March 14, 2008, 08:46:26 AM »

I tried to respond yesterday, but Scoop imposed its infamous timeout. When that happens I usually give up and log out, as I never wait long enough. It'd be nice if it showed a time remaining bar. You might try industrial surplus or agricultural surplus yards. Some machines use large drums or hoops. I've seen some pretty big and strange stuff used in mining. Have fun.

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Author Topic: heat from VAWT (Read 4206 times)