Savonius Rotor

[goodcompanion]

Here is a link to a bit of a video on my savonius rotor. Pretty big one! Kind of yanked my arm off when I tried to demonstrate how hard it is to slow it down!

http://www.youtube.com/watch?v=oinoEk4AvjE

We’ve been developing this design in collaboration with a retired turbine engineer, Victor Gardy. Nearing completion. It uses everyday lumberyard materials and construction techniques.

Really hums along in a nice breeze! We have not installed instrumentation yet so anyone’s guess what the output actually is. I would guess around 500 watts at the time of filming? At any rate the device is designed to produce adequately over the course of a year, under varied windspeeds. We are hoping to offset our entire farm electricity bill based on design projections. Ultimately we are going to install it like a big cupola on the roof of our big gambrel roof barn, where it will look more finished and architectural than it does in the raw, and the wind hums nicely up there too.

Costs about 3 k for the materials and all the components. We’ve been working on the project under funding from a SARE farmer grant to assess the potential of low-tech farmer-built wind technologies as an asset towards greater farm resiliency and economic viability. Full report on the project expected for the summer round of conferences, including NOFA in Amherst.

[Carl Russell]

Very nice. I like that design. Back in the 80’s I tried to imagine such a rotor, but never saw one put together. I hope it can perform up to expectations.

Carl

[near horse]

Wasn’t there a wind-powered (not sails) ship that Jacques Cousteau used toward the end of his “career”? If I recall, it looked like a Savonius rotor, at least it was a vertical axis. Like a big smoke stack with the rotor inside the stack. I saw it a long time ago when I still wanted to be a marine biologist:(

Erik –

what are you using for “bearings”? Also, how will you take the motion and covert it to electricity – belt drive to a generator? Cool.

[goodcompanion]

The shaft is a piece of 1″ iron pipe. The bottom bearing is a chevy lumina wheel bearing. The top bearing is a basic sealed ball bearing unit that fits around the pipe shaft and is housed in a wood block. At the base is a big (6 foot diameter) drive disc with a rubber tire. This provides the gearing. The generator has a rubber inline skate wheel on its shaft and bears against the tire of the drive disc with no belt.

The gearing ratio is about 34 to one. Under about 11 mph wind (site average) the generator should run at about 1400-1700 rpm which is I think optimal. But the generator is an exercise treadmill motor and as such is designed to function at a variety of speeds. What goes for output also goes for input, so I’m told….

Victor designed it and the builders (me and a helper) made some slight changes as we went along. Sure is fun to watch it go. Whether this translates into the farmer-built self reliance I am hoping for will be borne out (or not) by the production data. I will report in with actual numbers soon.

As a mention this design will be widely available, along with a construction manual, at the conclusion of the project this summer. Assuming the production data are favorable enough for anyone to want to build one, that is.

[goodcompanion]

@near horse 25178 wrote:

I saw it a long time ago when I still wanted to be a marine biologist:(

No great loss, you’re better off anyway. I knew a marine biologist once and he was a jerk. Also he got in hot water with the college for alleged sexual misconduct with a student, so that goes to show you too.

The student was a dolphin.

[OldKat]

@goodcompanion 25186 wrote:

No great loss, you’re better off anyway. I knew a marine biologist once and he was a jerk. Also he got in hot water with the college for alleged sexual misconduct with a student, so that goes to show you too.

The student was a dolphin.

Damn, talking about a sicko!

A friend of mine once told me that he was so influenced by all of the Jacques Cousteau specials in the ate 60’s and early 70’s, that he majored in marine biology at the University of Mississippi (Ole Miss).

He said 6 months after he graduated he was out in a swamp in Louisiana, standing up to his butt in muck & mud and burning up in the hot summer sun while counting mosquito larvae when he suddenly looked around and said “what the heck am I doing here?” Two weeks later he was working in another industry. He said “You know, I think Jacques Cousteau should be shot. He screwed up so man young people’s lives by letting them think that they could follow in his footsteps”. I think he was kidding, but was not sure.

[near horse]

Worst part is old Jacques wasn’t a marine biologist at all. He was an “adventurer” that young kids thought was a marine biologist. He did work on SCUBA though so I’ll give him that much.

Yea, I changed my path after a couple of ill-fated research cruises – people puking, cold wet and no going back until the appointed time. That was like the carnival ride from hell.

Speaking of carnival rides Erik – come fair season, you could take your rotor to the fair and with some good wind, charge kids $1 or 2 to get inside and let the wind spin ’em – then also sell anti-nausea meds nearby. Now that’s farming!

I’m not sure I want to know how one molests a dolphin!!?

[goodcompanion]

@near horse 25216 wrote:

Worst part is old Jacques wasn’t a marine biologist at all. He was an “adventurer” that young kids thought was a marine biologist. He did work on SCUBA though so I’ll give him that much.

Yea, I changed my path after a couple of ill-fated research cruises – people puking, cold wet and no going back until the appointed time. That was like the carnival ride from hell.

Speaking of carnival rides Erik – come fair season, you could take your rotor to the fair and with some good wind, charge kids $1 or 2 to get inside and let the wind spin ’em – then also sell anti-nausea meds nearby. Now that’s farming!

I’m not sure I want to know how one molests a dolphin!!?

“I don’t think it’s right for people to do things like that with fish.” –Marge Simpson

The bit about the dolphin was a joke of course. Dolphins are way too sophisticated to attend my alma mater. The student in question was actually a type of manta ray.

I have a great idea to add to your great idea. What if I tow the rotor to Amherst in a flatbed trailer behind an electric car, and use the wind as its going down the interstate to charge the batteries in my car. Then the faster and further I go the more charged up the batteries will be. Or am I missing something?

[blue80]

Nice Erik, please keep us posted. I closely followed projects like Mag-Wind http://www.wind-works.org/articles/Mag-WindPyramidalPower.html as I thought VAWT’s hold some higher benefits, but haven’t seen the results to show it yet….

[near horse]

@goodcompanion 25218 wrote:

“I don’t think it’s right for people to do things like that with fish.” –Marge Simpson

The bit about the dolphin was a joke of course. Dolphins are way too sophisticated to attend my alma mater. The student in question was actually a type of manta ray.

I have a great idea to add to your great idea. What if I tow the rotor to Amherst in a flatbed trailer behind an electric car, and use the wind as its going down the interstate to charge the batteries in my car. Then the faster and further I go the more charged up the batteries will be. Or am I missing something?

I was waiting for “So long and thanks for all the fish!” Hitchhiker’s Guide to the Galaxy.

Mmmmm – do ya means youse lectrcal auto mobile cain’t pull nose treeler nor makeit dat fer weet aught no cherge?:eek:

Hey – you just invented the perpetual motion machine!

[goodcompanion]

@blue80 25219 wrote:

Nice Erik, please keep us posted. I closely followed projects like Mag-Wind http://www.wind-works.org/articles/Mag-WindPyramidalPower.html as I thought VAWT’s hold some higher benefits, but haven’t seen the results to show it yet….

Seems like the rotor in that project was one that was billed as a commercial alternative to a HAWT. I wouldn’t claim that of mine. But I would say that it’s likely that an individual could build their own and redeem the cost of the project very quickly in energy savings.

The beauty of ours is not that it’s super efficient but that it’s big, sturdy, and very cheap to build. Low initial costs set the bar for payback period very low.

[Andy Carson]

This is great. I love these designs that are so far away from what I would have guessed an optimal design be (I would have guessed something more similar to a postcard from Holland) 🙂 I will be following this thread closely, as my place is also windy much of the year and I was not liking my power bill this winter. I am curious if there was thought put into what wind velocities might be too high? Would you predict the turbine will need shut off if the wind is very strong? Perhaps this is another strength of this design over the vane-type design???

[goodcompanion]

@Countymouse 25227 wrote:

This is great. I love these designs that are so far away from what I would have guessed an optimal design be (I would have guessed something more similar to a postcard from Holland) 🙂 I will be following this thread closely, as my place is also windy much of the year and I was not liking my power bill this winter. I am curious if there was thought put into what wind velocities might be too high? Would you predict the turbine will need shut off if the wind is very strong? Perhaps this is another strength of this design over the vane-type design???

Supposedly the savonius is resistant to damage from overspeeding. We have had some pretty high speeds and it has done well so far.

One of the things, at least in our region, that causes damage in high winds is not the high wind itself but the gusting patterns. Usually in high wind conditions, the wind is sort of generally powerful from a given direction, and then periodically a gust will come in from about 20-30 degrees off the dominant direction at higher velocity. For a HAWT, this forces the device to turn into the gust while moving at high RPM–due to the gyroscopic effect of the turning prop, this is very hard on the device and all of its components, and is a leading reason why northeastern HAWTs degrade faster than those out west.

With a VAWT the gusting pattern really doesn’t affect it, since it is always facing the wind.

[Andy Carson]

Fascinating. Another question. Why two smaller turbines instead of one larger one?

[goodcompanion]

@Countymouse 25234 wrote:

Fascinating. Another question. Why two smaller turbines instead of one larger one?

The size of the device is determined by the materials. These rotors are as big as they can be and still be made out of 4 x 8 sheets of plywood. To increase power further you need bigger materials or just add more rotors of the same size until you reach your estimated production target.

Often you see these things made with 55 gal drums but the plywood design has a much larger swept area than the drums, hence, more power.

The side by side design works in sites with consistent wind directionality. Here almost all wind comes from the due south or due north. If your winds were less consistent then totally independent towers would be better. I am still not sure the side by side design is a worthwhile one, even here. It is better than a single tower, but maybe not twice as good. The advantage is that all generation and monitoring can be housed in one location.

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