Author Topic: VAWT fiddling started...  (Read 5634 times)

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DamonHD

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Re: VAWT fiddling started...
« Reply #27 on: October 06, 2007, 08:32:15 AM »
Doing a little experimentation while the in-laws were round.  They didn't seem to think that waving a HAWT on the end of a 10' pole was remarkable, never mind the flimsy VAWT on a stick...  Maybe the funny-farm white-coats will turn up later.


Anyway, the point of my experiment is that in (messy) wind that would not even twitch the blades of my tiny HAWTs the VAWT was happily turning, at least in part IMHO due to the extra torque of the blade area facing the wind.  In fact, the VAWT was starting to spin so fast that it was starting to self destruct a couple of times!


So, maybe tomorrow I'll start to make a slightly more substantial foot-wide Savonius rotor from a 5l water bottle.  It has square-ish corners so I'm considering as an alternative using the corners as four pieces of a squirrel-cage arrangement instead.


Any suggestions either way?  Which might give the more bang for the same buck (which is more than I shall be spending on it)?


Rgds


Damon

« Last Edit: October 06, 2007, 08:32:15 AM by DamonHD »

ghurd

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Re: VAWT fiddling started...
« Reply #28 on: October 06, 2007, 09:08:43 AM »
I think you mean use the largest sides, with 1 corner each, to make one of these like in warpsta's diary?

I thought about it, never tried it.  Must be better than a 4 piece squirrel cage?

http://www.otherpower.com/images/scimages/8909/Blade_ends.jpg

G-

« Last Edit: October 06, 2007, 09:08:43 AM by ghurd »
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DamonHD

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Re: VAWT fiddling started...
« Reply #29 on: October 06, 2007, 09:51:36 AM »
That's a third good alternative.


Why would it be better?  I'm after suggestions for tomorrow's labours!


Rgds


Damon

« Last Edit: October 06, 2007, 09:51:36 AM by DamonHD »

ghurd

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Re: VAWT fiddling started...
« Reply #30 on: October 06, 2007, 10:40:15 AM »
Well, 4 buckets is about like the 1000 year old low efficiency design, and Sandia spent a lot of money researching?  Plus Sandia published design ratios to keep the guess work to a minimum.


I keep thinking I'll try a tiny one with some fancy shampoo bottles, or a huge one with a heavy duty 4 gallon square pail (Sam's Club changed their "Wind Fresh" laundry detergent packaging from round to square).  'Huge' in this case being about 11" wide and 8.5" tall.  :-P


Square buckets are obviously superior to round, because 40 pounds washed 160 loads in a round bucket, and 32.5 pounds in a square bucket washes 200 loads. Large increase in efficiency!

And with a name like 'wind fresh', who could resist? See my photos for ugly30efkabucket (not a VAWT).

G-

« Last Edit: October 06, 2007, 10:40:15 AM by ghurd »
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DamonHD

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Re: VAWT fiddling started...
« Reply #31 on: October 06, 2007, 11:26:21 AM »
Did it cut through all those wires nicely!


OK, seriously, if I do a design as you suggest, do I have the long sides meet in the middle, eg the V/cup at the outside?


What kind of angle should the long side make to a diameter?  Parallel?


Should I leave a big gap in the middle analogous to the Savonius?


This will be testing my handiwork skills severely!  B^>


Rgds


Damon

« Last Edit: October 06, 2007, 11:26:21 AM by DamonHD »

DamonHD

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Re: VAWT fiddling started...
« Reply #32 on: October 06, 2007, 11:36:48 AM »
Hi,


I realise looking at the picture again that, yes, the V/cup is at the outside: doh!


But the 'should the long part be parallel to or angled from the diameter' and 'should there be a gap in the middle' bits are non-obvious I think.  Any suggestions/feelings/prods would be welcome!


Rgds


Damon

« Last Edit: October 06, 2007, 11:36:48 AM by DamonHD »

ghurd

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Re: VAWT fiddling started...
« Reply #33 on: October 06, 2007, 01:48:44 PM »
The Sandia thing?  This isn't perfect.

The bottles of $20 a pint shampoo and $20 a pint conditioner my teenage daughter thinks she has to have are better matched to the Sandia specs, but too tiny to count.


What I was thinking for the new square buckets,

The bucket from above, the cuts, and a pair of VAWTs from 1 bucket, that probably won't work if I do it. (my VAWT luck has been less than impressive)

Use your imagination to lay this over his end profile.



« Last Edit: October 06, 2007, 01:48:44 PM by ghurd »
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TomW

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Re: VAWT fiddling started...
« Reply #34 on: October 06, 2007, 02:12:43 PM »
G-;


Hey, neat use of on hand parts! $20 a pint hair care products. Jeeze. Stepdaughter here is same way but lives elsewhere on her own dime so not my problem.


We get strawberry buckets occasionally from a bakery that are square tubs but a bit wider at top than bottom. Might be another source. They are 5 gallon white plastic usually. Don't have any around just now but if I see one I will get a picture.


Just remembered, I have a few of WindStuff Eds educational turbine kits here I never got to use for the class I gave after I had the heart attack. Might have to join this vawt craze and get them assembled and running.


Cheers.


TomW


Cheers.


TomW

« Last Edit: October 06, 2007, 02:12:43 PM by TomW »
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ghurd

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Re: VAWT fiddling started...
« Reply #35 on: October 06, 2007, 03:04:14 PM »
Hey TomW,

This particular step-kid has money to burn.

Her "mother's" checking account is apparently bottomless.  Step-dad will work 32 hours a day to replenish it.  The money spent on her college education doesn't count. Her bio-dad's $5/day support really helped, before she turned 18 and before she started college. He plans on suppling a little money during her college.

Ha-Ha!  I crack myself up.

Maybe that's just how it looks from here.


I spend much time each day sitting, planning, and looking at the bottles on the bathtub. Nuff said about that situation.


I figure to split the difference on the gap (top/bottom) difference.  

Something like the spiral / helical VAWT designs.  Too much something in one place evens out too little of it in another place.

Too narrow at the top means too wide at the bottom?  Self balancing?


Ed's minigen might be perfect for this?  Low power, low RPM, but needs torque to get it going.

Not sure the educational turbine kits will get enough RPMs with this kind of blade.


Everybody should study those bottles on the bathtub tomorrow morning, shortly after the second cup of coffee.

G-

« Last Edit: October 06, 2007, 03:04:14 PM by ghurd »
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DamonHD

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Re: VAWT fiddling started...
« Reply #36 on: October 07, 2007, 12:17:58 AM »
Thanks!


I hadn't thought of doing two levels...


Maybe I'll start with one level first.


Handily, my plastic bottle has indentations about 1/3rd of the way along each side just begging to be made into cuts.


Is there an 'optimal' opening size for the 'cup' or indeed between the parallel long parts?


I've found Sandia's VAWT papers but is there one in particular that covers this so I can give it a better read?


Rgds


Damon

« Last Edit: October 07, 2007, 12:17:58 AM by DamonHD »

ghurd

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Re: VAWT fiddling started...
« Reply #37 on: October 07, 2007, 07:52:19 AM »
They had a sketch showing ratios. Lengths, gaps, radius, etc.

My plan is to start with the radius and work from there.

My luck finding specific items on their site is not so good, but it's in there somewhere.


I have a paper copy somewhere. I'll see if I can find it tomorrow.

G-

« Last Edit: October 07, 2007, 07:52:19 AM by ghurd »
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DamonHD

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Re: VAWT fiddling started...
« Reply #38 on: October 07, 2007, 08:03:27 AM »
OK, I may postpone my hacksawing until then!  My over-the-top PM gen for experiments should arrive tomorrow sometime...


As a vague handwaving suggestion, what fraction of the radius should be the open cup do you think (without the parallel long-piece covering it)?  10%, 30%, 70%?


You seem to be clear on that diagram that there is no straight-through central air gap, but that there is space for air to flow sideways from the catching cup between the overlapping long sections, if I have understood correctly.


I may go and have another look, when I'm feeling patient.  (I'm feeling cranky right now because I managed to delete ALL my stats data so far while trying to put in place a backup system for it.  Grrrrrrr.)


Rgds


Damon

« Last Edit: October 07, 2007, 08:03:27 AM by DamonHD »

DamonHD

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Re: VAWT fiddling started...
« Reply #39 on: October 07, 2007, 09:01:21 AM »
I think the report I need is the SAND76-0131 "WIND TUNNEL PERFORMANCE DATA FOR TWO- AND THREE-BUCKET SAVONIUS ROTORS" but at the moment I'm only able to get at the abstract...


Rgds


Damon

« Last Edit: October 07, 2007, 09:01:21 AM by DamonHD »

DamonHD

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Re: VAWT fiddling started...
« Reply #40 on: October 07, 2007, 09:20:52 AM »
OK, the wonder of Google pulled up the full version of that Sandia paper, but I also came across this:


http://www.fieldlines.com/story/2004/4/20/122735/478


Rgds


Damon

« Last Edit: October 07, 2007, 09:20:52 AM by DamonHD »

ghurd

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Re: VAWT fiddling started...
« Reply #41 on: October 07, 2007, 09:29:09 AM »
That's the one!


Those crazy square dots in the center were just for a reference point.

Not sure what I did to the size of that sketch, but at least it's only 1.8K. :-)

G-

« Last Edit: October 07, 2007, 09:29:09 AM by ghurd »
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DamonHD

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Re: VAWT fiddling started...
« Reply #42 on: June 18, 2017, 03:01:12 PM »
Rave from the grave!

Was just refreshing this page of mine:

http://www.earth.org.uk/VAWT-experiment3-scanner-box-and-real-PM.html

and repaired the FL link to point at this thread (well, I think it's this one!).

Rgds

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Re: VAWT fiddling started...
« Reply #43 on: June 18, 2017, 04:42:36 PM »
Wow that goes wayyy back.
Back then, they didn't have terms like "upcycling" for cereal boxes.  :)
No one believes the theory except the one who developed it.  Everyone believes the experiment except the one who ran it.

System spec: 135w BP multicrystalline panels, regulated by Xantrex C40, DIY 8ft diameter wind turbine, regulated by Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024