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Big Al Newbie Joined: 06/10/2010 Location: United KingdomPosts: 38
Posted: 04:09pm 10 Oct 2010
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Gordon . I must admit I doubt it too altho I live in hope as the UK wind survey (on 1 Km square basis lists 4.2 M/s for this post code (from memory all thes e figures and mmine are quoted at 10M above ground level as are our weather forecasts. My house is far less exposed and its a pure fluke that at 10-11M height at the bottom of my garden there appears to be nothing between me and the gargunnock hills 5 miles away (which have big Hawts on them ).
i don't know what you call peppered but we have at least two big wind farms within the distance to the Gargunnock hills (about 5 miles maybe a bit less ).
Anyway I live in hope.
By the way that little extract you quoted from was the final section of a "failed " post-Don't know what happened but will repost. RgdsBig Al
Hi group,
Another newbie long on ideas and short on theory... I have recently moved into a new house built on a hillside overlooking the ocean,looking into the teeth of the prevailing S.E. trade winds and it does seem a shame to not harness them a little. A fair proportion of the time (like now!) we have 8-12 M/s, helped by the topography which involves a 40 degree slope rising around 30 metres from the sea. In the circumstances, is it feasible to consider a Savonious mill with the shaft horizontal and a couple of metres from the ground,oriented for the S.E.'s, with the lower half shrouded? This setup would simplify the engineering lots, allowing multiple blade sets with intermediate bearings, etc., and although not technically efficient it should be torquey and rugged. It would also not impinge significantly on my outlook... very important!
Fire away!
Cheers,
Bananabender.
Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333
Posted: 01:09pm 11 Oct 2010
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This must be the year of the Vawt and now a horizontal Vawt???
What is it with every new person considering building a wind generator wanting to build a Vawt??
To put it simply they are not worth the effort and the cost to build for the return they give back.
It is no easier to build a Vawt compared to a Hawt and the cost is about the same.
The return of power given from a Hawt can be as great as 10 times that of a Vawt for the same cost.
Some how people think a Vawt is safer, and if so its only because they don't work well enough to ever reach enough speed.
The whole essence of a wind generator is the need for enough speed (rpm) to generate power efficiently, and a Vawt can have plenty of torque but no speed in rpm, if gearing is used its a loss of energy in every way.
If you want a black and white answer forget the Vawt or even the HawtyVawt and put your efforts into a Hawt.
It will have far less impact on your view than some monstrosity of a Vawt contraption.
I think the best you could expect from a Vawt design is about 100 watts output where as a Hawt you can expect up around the 1000 watts.
One of Phills Chinese Hawts would suit your needs at a reasonable price.
You did say fire away
Pete.Sometimes it just works
Big Al Newbie Joined: 06/10/2010 Location: United KingdomPosts: 38
Posted: 03:32pm 11 Oct 2010
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Listen ,Pete and others . when me and the other heretics develop our vawts to several megaW from shoe box sized units the plans will be free to everyone except the dyed-in-the wool hawters who will have to pay 6c for them.
In the meantime if you've got any Kangaroo springs or Kryptonite spare (can't get either in the UK ) to help in the development we may look more favourably on yourself.
Sounds to me ,bananabender, as if the winds get any higher in your part of the world your house will soon be higher up the hill and you won't have to worry about spoiling the view.Big Al
Every Day is a school day (even at 67)
Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333
Posted: 04:58pm 11 Oct 2010
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Big Al you are showing your age now, as shoe boxes went out years ago and one would need to design with the use of plastic bags nowdays for the megawatt mill.
You are a bit greedy with the price of your plans to. (must be some Scottish blood in you)
As for kangaroo springs, they band us from removing them as we use to take the springs out and sell the rest to the poms as short wool sheep but they caught on to us a few years back.
Theres no Kryptonite downunder but lots of Kraptonite if thas any good to you
Im not against Vawts but dont see it practical to encourage someone to put the time and money into building something that will perform poorly.
I would much rather tell you up front and not see you waste your time (and shoe boxes) as you said yourself there is windturbines 5 miles away and these are Hawts for a reason.
Its your haggis and you can pound it anyway you want but i would much rather see you build a mill that is not doomed before you start.
Pete.Sometimes it just works
Big Al Newbie Joined: 06/10/2010 Location: United KingdomPosts: 38
Posted: 11:52pm 11 Oct 2010
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Hey,Mac. I'm going to try and put some of your coaching into practice (MOD-I will open post as if it works some of references may be of general interest , altho "heresy" ). Damn!! Did a google search to find the http of an article I have in front of me called "Economic Feasibility of Wind Turbines for individual households " and google can't find it (despite the fact I got it from the web). Tried Googling the Authors ( Claude Guillaume , Sandra Algazze and Emmanuel Duc ) that did n't work either so you're on your own.
Anyway this looked like a University thesis , relevant as they were not after gullible venture capital money. It looks to me very well written and scientific and is fully referenced. I quote from the introduction ..."so Vawts are potentially more efficient than Hawts, and also cheaper using straight blades with fixed pitch angle" Another quote "..the H-Darrieus design which uses straight blades , usually called SB-VAwT ...demonstrates the best ratio between the swept area and space requirement as well as the lowest cost to manufacture blades. Moreover the Reynolds number remains constant along the blade length."
If anyone more successful than me at finding this article its worth posting the reference as they test several NACA profile blades and conclude ..."in all computed configurations ,airfoil s2027 , gave the best results."
Somewhere I obtained and printed the foil shape and coordinates for S2027 and when I get off-line I'll try and dig it out and have another shot at finding the article I mentioned above. Then I can practice my http referencing .Big Al
Every Day is a school day (even at 67)
GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127
Pete,
As a newbie I hesitate to criticise those further along the learning curve than I, but I seem to sense a hint of negativity towards the VAWT approach, even though I offered to meet you halfway and have a horizontal axis! No pleasing some folk! As a dedicated avoider of authority I was hoping to stay out of the clutches of the local council and save a few trees by being inconspicuous and you've ruined all that, dammit! Oh well, next stop the recycle centre and the F&P heap...
At the moment it's a typical non-boating day, strong wind warning offshore and lots of air going by at 30 knots plus the local topography factor... the only way I can see to slow it all down and get some decent weather is to turn it into electricity and benefit from it, at least there's a modicum of satisfaction to be had there somewhere. Another problem is my advice that Ergon (our grid supplier) are unwilling to have anything to do with grid connected wind systems ... hopefully this will change as technology progresses.
Back to lurking...
Bananabender
Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333
Posted: 11:41am 12 Oct 2010
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Hi B-Bender,
I'm not totally negative to Vawts, but to extract power efficiently from the wind is a lot harder than most think and I'm sure you will find this out to.
I am yet to see a home built Vawt that is efficient as a Hawt, i would even settle for a Vawt that was 80% efficient.
I'm not one to sit back and tell you "its a great idea and go for it" when i know it will most likely give a crap result with little power and enough problems to cause you to abandon the project.
You come to the forum to get advice and to better understand the principles of wind energy, It would be a sad affair if we all just agreed on poor designs.
You must remember it has all been done before, tried and tested, with many failures or just poor results, the archives of the forum is full of projects like this, and if they worked well enough we would all be building them.
What i do surgest is you build a small model of your design and test the theory before committing time and resources to a full blown design.
There is a hell of a lot to be learnt from a mini mill with something like a stepper motor for a generator charging a few nicad batteries.
A bigger design dont mean it will work better than a mini mill, so if the mini mill works than scale the design up to suit your needs.
I think you will find a less than desired result and is why i bother to stick my neck out and tell you.
By all means prove me wrong, i have no problem with that, i just would rather not see you waste your time in trying what others have already done with poor results.
Pete,
No offence taken and your advice is appreciated... just a smigdeon of disappointment that a nice simple approach doesn't fit the physics but that's the way it works. I asked for opinions and you obliged and thanks for that... my only wind harnessing experience has been sailing and pumping farm water with a high-torque HAWT. I'll think some more about siting a HAWT tower but I foresee problems with neighbours and all that...
Cheers,
Bananabender.
Big Al Newbie Joined: 06/10/2010 Location: United KingdomPosts: 38
Posted: 02:07pm 13 Oct 2010
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bananabender, the fact that you work in smidgens augurs well for your project. Some of the hawts on this site have been built in tads .(I think Oz's chainsaw was cailbrated in tads ) which (as you'll be well aware , at 8.73 smidgens to the tad ) leads to sloppy engineering. At the end of the day there's no substitute for craftsmanship and if you work in smidgens at least if you ever take up brain surgery you're familiar with the units.
Don't worry too much about the neighbours , if you build a hawt without much experience not many of them will escape impalement and you'll be set up for kebabs at your "barbies" (Is that the word ? I'm still learning Strine but I know now what an F&P is. ) Don't worry too much about them hawters either. I know their attitude is a bit "Hawty" , but thats mainly because they have n't worked out how to make their masts horizontal and still have to use our VERTICAL pole design.
See u guys got your usual sporting luck in the third place table tennis doubles play off against the UK.
Many thanks to Gordon. I can put off upgrading my posting skills for a day or two.Edited by Big Al 2010-10-15Big Al
Every Day is a school day (even at 67)
Big Al Newbie Joined: 06/10/2010 Location: United KingdomPosts: 38
Posted: 03:35pm 13 Oct 2010
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Hey !! Found that thesis. Just in case I can't manage http referencing without further coaching from Mac I'll type it out here as it appears in my favourites list.
The space after the s of presentation should not be there and I can't seem to edit it out (more email/web magic I don't understand ?)
As u all kno my email skills are a bit rugged and I don't know why Google did n't find it. Is it becos its a PDF file ?
Anyway if anyones interested enuff to read it ( and assuming I've typed the above correctly and u find it ) it seems to me very good on solidity etc. As you can imagine as a yet unrepentent vawter its words are to me sheer poetry except they are written by the French (spit spit ).( Only joking no offence to the French but as our neighbours we are allowed to be as rude about them as they are about us. I love their country , think its too good for them , and they escaped our imperialist clutches illegally-Joan of Arc and all that.)Edited by Big Al 2010-10-15Big Al
Every Day is a school day (even at 67)
MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329
Posted: 04:25pm 13 Oct 2010
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Big Al
Next time you think you've lost something, run back through your "History" list; it's there--somewhere!
Another thing:
[Quote=Big Al]Is it becos its a PDF file ?
Maybe you can't find stuff on the Google searches "becos" (because) you didn't spell it right. Remember that old saying, "Crap in; crap out"? It's still true. Gotta be a little more careful with those imperialist pinkies!
. . . . . . Mac
Nothing difficult is ever easy!
Perhaps better stated in the words of Morgan Freeman,
"Where there is no struggle, there is no progress!"
Copeville, Texas
neil0mac Senior Member Joined: 26/12/2009 Location: AustraliaPosts: 210
Posted: 09:02pm 13 Oct 2010
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?
A : and a couple of // instead of the -- might help
Nope!
But ... http://www.ewec2009.info/?id=32 is a start.Edited by neil0mac 2010-10-15
Big Al Newbie Joined: 06/10/2010 Location: United KingdomPosts: 38
Posted: 09:04am 14 Oct 2010
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Thanks neilomac. Sorry guys, if my lack of web skills wasting everybody's valuable turbine building time. I just typed it as it appeared as a listing in my favourites file.
Have now clicked on it , got the article up and this is what it says in my header bar http://www.ewec2009proceedings.info/allfiles2/54_EWEC2009pre sentation.pdf
Except for that bloody space after the "s" of presentation which does n't edit out. What's going on here , Experts ?????
I hope I got that right -Ive checked it a couple of times and when I retyped it and pressed return it brought up the article. P.S. IT is right ,I put this in from this post and got the article right up !! DON'T put the space in.
Can anyone tell me why Google can't find this as a matter of interest.
Regards and apologies for failures to date . At the moment myself and a couple of other guys are repairing an Elliott 10M shaper belonging to a lady in Poland --by email!!--although I luckily have some spares to send her. ( She's quite a lady and seems able to manage anything mechanical in between help run a farm , teach English , and raising 4 kids and a husband ) -Anyway its leaving me a bit short of time what with the 1001 projects we all attempt to finish. Once I get some time , Mac , watch my smoke as I improve on the web. Little bit wounded by your comments on my spelling, at one time I was the world's 3rd. best speller ( there was a guy in Leamington and a girl in Cyprus who were better. "Two weeks ago I cudd n't spell injuneer and now I are one"
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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