Hawts and Vawts

[Patrick]

Hey Big Al, how's that VAWT coming along? You got me hooked on the idea and now I want to build one (a very simple one, that is). :-) Have you seen the discussion on vawts.net?

[skyl4rk]

Are you talking about this project:

5 Watts For 25 Dollars - windgen.org discussion

It is coming along nicely.

[Patrick]

Originally Posted by skyl4rk

Are you talking about this project:

5 Watts For 25 Dollars - windgen.org discussion

It is coming along nicely.

Not particularly. Mine will probably just be a "wind spinner," unless it looks like it has a lot of potential, then I might try to hook an alternator to it.

I have a HAWT that I got on Ebay that I will use to generate power. It would be interesting to do a side-by-side comparison, though. Hmmmm . . . .

[Big Al]

Patrick , things are moving. I should now have 30+ days of windlogging data and will post details of this asap so we know what sort of wind regime I have. meanwhile I've been reading sites and booke to get up to speed on whats necessary. I don't know what the etiquette is between various wind sites but have been reading a lot of the backshed.com posts and posting with my big mouth there quite a bit ( this site was down ).

Result of this so far I have 3 possibilities depending partly on what my wind logger throws up

1 The unexciting route is to build (I hope competently ) a good hawt > this route would practically guarantee the o/p I'm looking for but may give me planning problems , and neither myself or the neighbours would be aesthetically as pleased as with a Vawt. That matters to me.This route does n't sound very exciting and won't add anything to anyones experience and knowledge. Cleverer folk than I have done it all before and its too easy.I am also anti hawt for I think a good reason-I don't like maintenance. Spin a bicycle wheel held in both hands by the spindle/axle at say a low speed 10 rpm. and feel what it does when you try to change the plane of rotation. hawts have to do this all the while especially in the average domestic wind regime ,and altho they can be designed to stand this stress you are better off without it. The excellent Danish wind power site on big wind (excellent except" like the oil lobby" it only admits to hawts existing ) if read between the lines is paranoid about bearings. I'm not surprised-- they ought to be. This week I went to the UK Renewables conference and exhibition in Glasgow. What's in the really big Hawt nacelles is mind blowing in the sense its all unnecessary and very, very expensive . And have you read some of the blade replacement figures for big Hawts ? Anyone think replacing a blade on a 150m tower is cheap or safe ?

2. Slightly more exciting is to aim for the same o/p from a fairly standard Vawt, helically bladed and with sufficient solidity to be self starting . I think this may be possible but is difficult and may take a better man than me. However this is my fallback route.

3. The exciting route , having read up the Peter Allan Sharp and Bayly-Kentfield patents is a revolutionary state of the art Vawt . This is potentially a long route with much experimentation and maybe disappointment at the end. My opinion is that if I was n't 67 this would be the route to go and given time I don't think would end in disappointment , but I am 67.

4. I have a couple of revolutionary (maybe ) ideas of my own regarding Vawt design. Before shouting my mouth off , over the next 2-3 months I want to model these and see if I think they are possible. I also have a couple of revolutionary ideas (maybe ) on energy storage for home builders but again I would like a bit more time before deciding on these.

Route 3 has thrown a spanner in the works in that I have been watching for a while progress on the Cranfield college Vawt. I have a highish regard for Cranfield. This has now surfaced as Aerogenerator X and involves Arup, Windpower , and Rolls Royce and a lot of other high power names. If you google Aerogenerator X I'll think you'll find enough data there which if its half true (I believe it--- they've wind tunnel tested a 15KW version and if Cranfield are good at one thing its aeronautics-I don't see Rolls royce, Arup and some of the other names involved failing to exercise due diligence ) will consign Big Hawts to one of technology's dead ends. Just imagine an Aerogenerator X at 20MW with another 10MW unit concentrically inside it and maybe even more inside that . At 3 rpm the blade replacement guys should be out of business and if a say 30MW unit is possible (again at 3 rpm these things on land could be interwoven which kills Hawt o/p but can enhance vawt o/P if done cleverly ( "drafting" ) and you could MAYBE envisage several GW windfarms on 1% of the land required for Hawt windfarms without the fleets of large trucks, cranes and repair bills and without the Hawt associated environmental concerns. I would n't see this happening before 2025 but it could end up being the way we go. Then we'd really be getting green. ( I don't know , as a new boy , how green this site is but we need renewables IMHO and we also need nuclear -this is a no-brainer-interesting channel 4 evening of programs this week on "what the greens got wrong " .At the moment with Hawts getting bigger and bigger the cost per KW hour paradoxically goes up and up. Its getting like the oil lobby situation.

To come down to earth one things for sure, mine's going to be a vawt. If my progress seems slow that's OK by me. I always have several projects ongoing ( at the moment I' m renovating a Fritz-Werner H-V mill , two engraving machines and a tool and cutter grinder. On top of that my Grandkids generate a lot of projects for them. I'm also trying to mend a shaper for a lady in Poland (by email) and get a new telescope into commission.

The Vawt by the way is supposed to be just part of a larger project (before it took over my life !! ) for a heatpump system using my garden as a heat source and I'll be using A.C.Hackers excellent thread and work on this site for that.

(groan) However did I find time to go to work for a living !! By the way I have been following avidly the vawts discussion--its a site with very open minds IMO.

Edit addition. One of the things that came out of the Glasgow trip was an input from the Proven guys who make one of the best Hawts in my opinion and who did n't have an axe to grind as they were n't involved in Zeeland, is that the Zeeland tests were crap. I always suspected something very fishy in those figures. The Proven engineer made a point in saying it very loud in front of the Skystream stand who were next door . He did n't get any takers.

Every Day is a Schoolday.

Rgds. Big Al

[WisJim]

Couple of comments on VAWTs. First, none of the currently available units actually produce usable amounts of power, and typically have a payback of decades to centuries. The blades in a VAWT are stressed as beams, and need lots of support at high RPMS or they will break just like an overloaded beam. HAWT blades are stress along their length, along the radius of the rotor, and are much stronger in that direction. And third, a VAWT is much harder to put on a tall tower where the powerful winds are located. Putting any kind of turbine at ground level or near ground is not getting it up where the winds are powerful. No matter what kind of turbine, it needs to be up high!!!!

[itsandbits1]

a couple of points to past posts,
re: helix,it doesn't matter what shape of blade is downwind, it is still down wind, or in the shadow of the blade in front of it. With a lift blade though you get some power from the down wind side depending on the tsr and profile you use.
you can find a lot of usefull info on builds at this site for vawts and mills in general: www dot vawts dot net this is where 5-25 and the caleb I know lives

[Big Al]

Well, the plan for the several MW Vawt in a shoebox has hit a serious problem. I've now got 3 months of logged data and what it tells me is I have n't got enuff wind. About 1 m/s average. This I don't fully understand as from my windlogger in a straight line with no obstructions in the way are 3 or 4 large commercial Hawts. Were those guys crazy too ?? Only thing I can think of is that so far we have had a freakily cold winter with most wind from the North and NE which it is not where it is supposed to come from. Its supposed to come from the SW which would suit my little wind logger and the big commercial Hawts a lot better. So I shall continue logging ( raising my logger another few feet and possibly improving its siting slightly )-I ain't giving up yet.

Will try and get some photos posted of my site and maybe one of the knowlegeable guys can tell me why both me and presumably the guys who paid to put the monster ones on the hill are n't getting the wind we should.

Incidentally , driving around the area I have come across 2 Proven mills (I think from looking at them from about 40 yds ) . One in a valley on about a 15M tower which seemed to be defying the law of conservation of energy , spinning fast on what seemed to me a pretty windless evening.

I saw another one near Cumbernauld last week ( about 6 metres diameter on about a 11M tower) which seemed to be spinning a lot faster than it had any right to , although it was on a small hill and there was some wind.

Anyway rgds for now. Got a data logger to move and some photos to take.

[Big Al]

Been a while since I posted progress on the "megawatt in a shoebox project". Well things are moving. You might remember that the vast quantities of power generated were part of a larger project to put in a heat pump a la A.C.Hacker and I certainly did n't envisage paying a power provider to power my pumps. Meanwhile I have n't been letting the sheep cuisine grow under my feet , no sir.

Firstly I now own two excavators for putting in the ground loop. A small towable digger (a Powerfab procured in Ireland where they still go for reasonable prices ) which is in excellent nick and will do the digging. Secondly a Thwaites Tusker , much more powerful , but this needs restoring. Why two ? Well I got fed up with the rapid escalation of prices on Ebay during the last few hours and bid on two and won them both. When my 4 yr. old grandson asked why two? My reply was "Well , you want one don't you " He certainly did and the 18 month old also thinks "diggas " are the best thing since chocolate biscuits. The granddaughters are almost as keen.

Raised the Power predictor another couple of meters to about 14 meters and got improved figures but still short of a 5 meter/sec average , so I'm going higher. I have a 70 feet birch in the garden (a magnificent specimen and almost the highest thing around.) Plan is to fell a couple of 35 feet straight trees growing on wasteland just over my garden fence , splice these together to give me a 60 foot "telegraph pole" erect these about 7 feet from the base of the birch and construct a working platform between the birch and the erected pole. From this I will erect a third straight and smaller tree to carry , initially the Power Predictor and then my Vawt. This third pole will be raised and lowered from the platform to ensure easy maintenance and experimentation on the Vawt.

Sounds crazy but I think I can do this safely and as a bonus the view from the top of the birch is breathtaking. The birch has stood for decades resisting all winds and the small wind resistance of my "telegraph pole" , guyed and connected to the birch should give me a solid platform at about 60 feet allowing for splicing overlaps, and some " pole in the hole".

A 20 foot pole erected from the platform should give me a turbine at about 80 feet, 27 meters, above ground level , and higher than most things around . If I don't get an average of 5 m/sec up there there's something seriously wrong with the UK wind charts. Also as I will erect my pole on the far side of the birch , any tubine will be largely screened from the view of all residents which will aid planning permission.

Timescales ? I have to paint the house this autumn but hope to get the pole up by the end October and start measuring wind at this height. The megawatt in a shoebox will be designed over the winter, and I'll dig in the groundloop , next spring/ early summer.

Meanwhile its a race between me and aerogenerator X ( only Rolls Royce , Arup partners and others backing this one, so I should be favourite) to produce a megawatt Vawt. Warning to any new readers-the megawatt may have to be slightly scaled back to 5 Kw per day but I only need enough to drive my pumps.

Cheers for now.

[almightybmw]

Al, have you considered a height of over 70m? Most turbines and farms near me have a tower height of 70-110m. And that's for HAWT turbines rated at 7m/s wind for 1.5MW. Even reviewing a few VAWT designs (mostly Savonius) show that at 5m/s a 4MW design barely makes 0.5MW.

I'm not detracting from making a savonius or darrius VAWT, but I feel you need to get sufficiently above the ground layer into a clean air stream. Even a building 1 mile away will affect the ground layer at your site.

I've a real neat book I picked up for an Alternative Energies class that emphasizes wind energy (something my state has lots of).
Wind Energy Explained
Theory, Design and Application.

It has more math about capturing wind energy than you would want to read or learn. BUT the few equations it does have are what the major wind turbine producers use for building and siting wind farms; in that it would be useful to read it and apply the data to your site and see what kind of turbine design and size would work, if any.

[Big Al]

Thanks for input. I've got to go higher and have a plan which won't give me 70m but should give me 30m at which I would expect to see some improvement. My turbine was planned as part of a bigger project which is to install a ground loop heat pump (I can manage about 40m length in trenches ). That won't heat the house totally but should make a very useful contribution. The turbine output I envisaged as driving the pumps so I'm hoping to get enough output for this.
In the UK because we don't have the average plot size and acres of space that the US, oz, and New Zealand have our planning laws are tighter , altho I must admit that I have n't really investigated this yet. This means a 70 metre tower might be difficult (I live in a residential area , altho on the very edge of town. I intend to spend the minimum possible as I'm 68 and payback time is a consideration.
A vawt is more aesthetically appealing and I have some ideas that may help with output. I always have a lot of projects on the go and am quite happy to proceed at a slowish pace but things are moving. I bought a couple of diggers this summer (one goer to do the digging and a beefier one for restoration and then digging if my ground proves as rocky as I expect ). I certainly think boreholes would be difficult (we're pretty regulated on these too ).
To get enough o/p to drive the heat pump system , I'm going to have to use every trick I can with a vawt at 30m and am considering wind lensing (aesthetically ok again) , one or two ideas for efficient self starting, and a few other ideas which I will need to test with models first. I had hoped to do this last winter but other projects keep intruding. I'm pretty relaxed about this however as they are all interesting and I'm not in a race.

On my side I have an extensive metal working facility (some of which generates projects which keep intruding ) , and I think a cheap and easy way to achieve 30 metres altho this will not put the turbine in a clean airstream ,BUT it will be higher than most things around it.

I'm also watching the progress of Aerogenerator X , which you can find if you google it, as this seems a good vawt approach to higher power at a lower altitude, but this is largely unproven . Some of the companies backing it are no slouches so there may be something in it.

Rgds. and thanks for interest