I have access to this decorative windmill. It’s been in place for decades, spins freely in the wind, and has made millions of revolutions in its lifetime. Its RPM’s are impressive even in relatively low wind.
What are your thoughts on how I should harness this energy?
Step 1) Wire it up
Step 2) Wait for lightning
Get any cheap small electric DC motor and attach it somehow (pulleys?). It won’t be as efficient as possible, but it’ll work.
But also: sucking power out of it will create resistance and might stop it from spinning in low-medium winds.
You can’t realistically do it. Even is you find a tiny enough generator the amount of power would be so small it would barely light a led in a high wind.
Try turning a bike generator by hand, it takes a lot to generate a little power.
Search on diy wind turbine and start from scratch.
https://www.rwu.edu/news/news-archive/how-build-your-own-wind-turbine
Agreed. The “impressive RPM” mentioned in the OP won’t matter, because it’s about angular momentum, not specifically angular frequency. You would certainly be putting in more energy to build it than you’d conceivably get out. At best this would be a “fun learning experience in your garage” project.
I agree that RPM isn’t the primary quality to assess here, but I think angular momentum doesn’t really matter either. As a quantity, momentum describes a conserved capacity to store kinetic energy. As in, it could tell us how long the fan would stay in motion when the wind stops blowing. But that’s not the objective for a wind turbine, which is supposed to convert lift from the wind to do some work.
At bottom, none of these quantities are the useful metric for what makes a good wind turbine. And that’s expected, because we have few details about the fan itself: the blade pitch, stall speed, and fan diameter, to list a few parameters. The only firm detail we can see is the blade count from the picture.
N… No? The wind applies a torque to the wind turbine that gets converted into angular momentum. The angular momentum drives a generator that produces electricity. That’s literally the entire point of a wind turbine.
The obvious point I was making was that the electricity produced doesn’t rely just on ω but also the moment of inertia I.
I feel like I’m being gaslit right now. Like: “Linear momentum isn’t the useful metric in assessing how deadly a collision with this car would be. I feel like that’s expected because we have few details about the car itself.” ???
Edit: And if you mean torque (because P = torque * angular frequency), then torque is just the time derivative of L. My point being that even if frequency is high, L here is piddly.
I believe you’re thinking of momentum in a narrow sense: the energy an already-moving object has that allows it to move for a while before stopping. And it was meant in a more general sense ie the amount of energy being generated and doing work.
Counterpoint: even lighting an LED with a tiny working windmill is pretty neat.
As long as we’re all clear that that’s the only thing OP can expect, sure. If OP is wondering how much they can knock off their energy bill with this project, the answer is jack shit.
I kinda doubt OP was under the impression they were gonna save Big Bucks with a decorative windmill slightly larger than a kid’s pinwheel, but people have believed dumber things I guess
Counter counter point: It is neat, IF it works.
Or you can do what my neighbors did and just buy one.
Tried to find a link to the wind powered lawn ornament but couldn’t. You will have to satisfy your windy lust with this.
https://campingguider.com/portable-wind-turbine-for-camping/
Replace the base with a solar panel. You won’t get any meaningful power out of that tiny blade setup from wind.
Won’t generate much electricity, but for fun, you could just direct mount a bike dynamo on to it and connect to a simple led. You could probably get it to work if you oil it up well. Can also buy a battery management board and connect to a battery so the light can work when there’s no wind!
Alternatively, bore a hole down to the aquifer and let it pump water slowly with mechanical power. That would cost more though.
Use the clone tool to increase the size by at least 1000%
Start over from scratch
You can try just hooking on a chain and a dynamo.
But that entire blade mechanism looks way too heavy for its size. You won’t get much out of it without replacing it with something a lot lighter.
Cut the top off and mount a proper turbine fit for purpose.
Hook a small motor to it. Small is key, a bike light is too big. Those toy ‘stomper’ trucks that run on a single AA battery is about all I would hope for. Of you want useful power you need longer blades and less of them. These are designed to turn fast with very little wind without going to fast in big winds. It should be fun and you learn, but of you want useful it is a waste of time. You’re choice of goals.
magnets and copper wire?
and a slip ring.
and maybe a sand battery?
or maybe a corkscrew to lift water, as a secondary store of power potential, that could then be toggled on to flow in low wind to keep a turbine going.
You’re not going to be able to generate much power from that.
Do you have a bike with a dynamo powered light somewhere? You could try hooking that up somehow.
And bike around the neighbourhood playing Snap! - Power.
I’ve got a power! 🎵✨🤭
Fucking magnets!!! How do they work???
They work until you put them in the water
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Simple answer: making it do meaningful work will make it harder to rotate (kind of like increasing the setting on a stationary bike) and something this size won’t be enough to power anything useful.
Maybe one of those solar garden lights? But those already run fine on solar.
I’d say leave it and enjoy the free spins in the wind, those are more valuable than the tiny bit of energy this can give you.
