Local production, reliability, easy repair, and low embodied energy
June 17, 2019 9:44 AM   Subscribe

Low-tech Magazine does small wooden wind turbines.
posted by clawsoon (31 comments total) 47 users marked this as a favorite
 


And on the other end of things: Offshore wind turbines the size of the Eiffel Tower.
posted by gwint at 9:53 AM on June 17


I fantasize about building my own variable-pitch vertical axis turbine*. One efficiency problem VATs face is that any given blade is pushed by the wind half the time, but has to fight back through the wind the other half of the time. BUT if you mount the blades on an armature, and have the blades themselves rotate within the armature at half the rate that the armature rotates around the central axis, then the blades can present a full profile when they're travelling with the wind, but present a minimal profile as they travel against the wind.

Like this (looking down from above the turbine, assuming wind blowing to the right in the diagram, blades turning clockwise):
    
               |
          ---> |
               |
             
             
\                             /
 \                           /
  \                         /  


             
             ------
*yes, horizontal axis turbines are more efficient, but my wife can't stand how they look in motion.
posted by Jpfed at 10:03 AM on June 17 [2 favorites]


I am a big fan of this!
posted by Greg_Ace at 10:03 AM on June 17 [11 favorites]


I am a big fan of this!

Pun-like typing detected.
posted by clawsoon at 10:06 AM on June 17 [13 favorites]


I am a small, local, decentralized fan of this
posted by aparrish at 10:18 AM on June 17 [17 favorites]


(Normally we are encouraged to RTFA -- and probably you ought to in this case -- but also just know that low-tech magazine is a self-hosted, DIY, solar-powered website that may not withstand the traffic.)
posted by notyou at 10:22 AM on June 17 [3 favorites]


oh my god they have a print copy of their website these people are the best ever ❤ ❤ ❤
posted by ragtag at 10:26 AM on June 17 [6 favorites]


The solar site is in addition to the main site. You can tell which site you're on by the stylized choice they made for the images. This is the FPP article on the solar site.
posted by clawsoon at 10:31 AM on June 17 [1 favorite]


This is terrific. I love the idea of winch erected sectional towers. It makes sense and returns a human scale to everything.
posted by meinvt at 10:31 AM on June 17


Jpfed, are you thinking of a lift-based design or a drag-based design?
posted by clawsoon at 10:43 AM on June 17


I am a big fan of this!

Windmills do not work that way!
posted by delicious-luncheon at 10:47 AM on June 17 [10 favorites]


Jpfed, are you thinking of a lift-based design or a drag-based design?

What I mentioned would work with drag-based. I don't understand lift-based designs well enough to say "this would work for them" and I'm guessing it probably wouldn't. There are variable-pitch lift-based designs, but they sort of periodically wag the blades in ways that haven't clicked for me yet.
posted by Jpfed at 12:33 PM on June 17 [1 favorite]


I don't really understand lift-based vertical-shaft windmills either. :-) Horizontal, sure, vertical has got some vectors going on that I haven't wrapped my brain around.
posted by clawsoon at 12:38 PM on June 17


I love the idea of winch erected sectional towers.

And when you want to erect your sectional tower, they have a nice article on human-powered cranes and lifting equipment, too!

I've wanted to experiment with windmills and solar-powered off grid stuff for a while, but as I have the blessing/curse of a tree-enclosed, heavily-shaded yard, there's basically no wind and no sunlight to work with. And I can't bear to cut back the trees around the house, because I like them and because they provide a lot of shade in the summer, such that I think the net energy impact of trimming them to install solar might be going in the wrong direction. I think the ROI of a shade tree is pretty high in terms of lowering AC usage in the summer, if it keeps the sun off your house.

Low-Tech Magazine is a hell of a rabbithole.
posted by Kadin2048 at 12:38 PM on June 17 [4 favorites]


Some teenagers I knew back in the 1970s (when I was in my twenties) built a cool Savonius rotor made out of old metal barrels in my back yard but never hooked it up to anything, it just spun and spun for years and years on a very windy hilltop outside of Ithaca, NY.

I want one of those sculptural wooden ones!

Low-tech is my new favorite, thanks!
posted by mareli at 12:41 PM on June 17


Ah, I knew this would be about Hugh Piggott when I saw the headline. By coincidence, I'm probably no more than 15 km from his community at Scoraig as I write this (in Ullapool). Brilliant engineer, great teacher, and has been living with the things he builds for decades.

Good luck with your design, Jpfed. VAWTs are have some intrinsic disadvantages that make them quite unattractive to work with. Most critically, the tower experiences the worst fatigue loads possible. They are also almost impossible to make self-starting. Take care that your pitching mechanism doesn't generate so much friction that it would be more efficient to keep pitch constant
posted by scruss at 12:53 PM on June 17 [2 favorites]


I fantasize about building my own variable-pitch vertical axis turbine

There's a start-up here in NZ making those called WindCatcher. The blades open and close with each revolution. As soon as I think about the structural fatigue from the repeated opening and closing of the blades, I have to say "hell no".

There are many fundamental reason why horizontal-axis turbines have taken over but a key one is fatigue. The loading on the blade on a horizontal-axis turbine is pretty constant, the wind is blowing from one direction. There's little fatigue so the blades can be light, reliable, and affordable.

The loading on a blade on a vertical-axis turbine is the opposite. Every time the turbine rotates, the wind load switches from pushing on the front of the blade, to pushing on the back, to pushing on the front. From a fatigue point of view, that cyclic loading is as bad as it can be. Imagine grabbing a road sign and pushing back and forward on it, one per second, for years. You're going to break it.

So the blades on these machines have to be built to survive fatigue loading, they end up heavy, unreliable, and expensive.

Horizontal-axis wind turbines have won this battle.
posted by happyinmotion at 1:08 PM on June 17 [2 favorites]


oh, this magazine looks awesome! Thanks for telling me about it
posted by rebent at 1:29 PM on June 17


When I was a kid, one of the games we played on road trips was "windmill." You score a point for each windmill you saw first. There were so many that it could be exhausting! Now I can't remember the last time I saw a rural windmill that was still operating.

It was years before I understood their function. Typically, they operate a reciprocating pump through a crank to fill a watering trough. A float valve, much like in a toilet tank, operated a clutch to shut down the pump when the trough was full.

Apparently there are now more cost-effective solutions. Now it would be simpler to install a solar-powered electric pump. But that would be somewhat of a shame since that requires a deeply-interconnected and highly-sophisticated technology chain to implement. Wind pumps could be manufactured and maintained with technology readily at hand, and that seems charming to me and possibly important just in case.
posted by sjswitzer at 1:33 PM on June 17 [2 favorites]


I am a small, local, decentralized fan of this

Are you made of wood?
posted by justsomebodythatyouusedtoknow at 1:49 PM on June 17 [2 favorites]


Those sectional towers ... maybe it's just me, but I'd paint the holy bejeezus out of them because wind turbine failure is distressing at the best of times and having an old, rotted (rainy climate), tower come apart under load seems like a quick way to bisect a number of people...

...or maybe I'd use acetylated wood instead. But definitely not just plain ol' wood.
posted by aramaic at 2:02 PM on June 17


Low-tech Magazine articles come in two flavours for me: "That sounds really interesting!" and, "That sounds like a slave-labour dystopian nightmare!"
posted by clawsoon at 2:05 PM on June 17 [9 favorites]


I fantasize about building my own variable-pitch vertical axis turbine

These already exist.

But the same idea is already commonly used on the underneath of ships (mostly tugs and ferries) to provide omnidirectional propulsion, because you can change which part of the rotation the blades push against the water - and therefore which direction the thrust goes - with a fairly simple linkage.
posted by grahamparks at 2:53 PM on June 17 [4 favorites]


Low-Tech Magazine is a hell of a rabbithole. - Kadin2048

Low-tech Magazine articles come in two flavours for me: "That sounds really interesting!" and, "That sounds like a slave-labour dystopian nightmare!" - clawsoon

Pedal powered farms and factories: the forgotten future of the stationary bicycle
posted by Iris Gambol at 3:41 PM on June 17 [3 favorites]


I'm trying to figure out what I'd actually DO with a small wind turbine. A mechanically-driven heat pump linked to thermal mass storage, maybe?
posted by the man of twists and turns at 4:18 PM on June 17


Pedal powered farms and factories: the forgotten future of the stationary bicycle

How many merits will that get me?
posted by tobascodagama at 5:02 PM on June 17 [4 favorites]


Merits... d'you suppose we'd get our own rooms, and everything?
posted by Iris Gambol at 5:14 PM on June 17


Now it would be simpler to install a solar-powered electric pump … that requires a deeply-interconnected and highly-sophisticated technology chain

Hey, they might be stamped metal parts and a few castings now, but the Chicago farm windmill boom of the 1860s was the original high-tech integrated supply chain. Lots of companies competed for the most efficient designs, building some of the first wind tunnels and theory backing up the designs. Everything was transported to near site by the new wonders of railroad. The technical dead-ends are so long forgotten that we only recognize one design these days
posted by scruss at 8:37 AM on June 19 [2 favorites]


scruss, if you have any further reading to suggest on the Chicago farm windmill boom of the 1860s, I would be fascinated to read it.
posted by clawsoon at 5:14 AM on June 20


Paul Gipe's Wind Energy Comes of Age (Wiley, 1995) has something about it. Paul's done a lot of writing on history of wind power, and was an early turbine wrangler in the pre-PURPA US wildcat renewables days.

(I'm a friend of Paul's and likely have the only copy of this book in Toronto. Happy to lend it out)
posted by scruss at 11:06 AM on June 20


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