stevepoxy456, not at all my area of expertise, but I'd think these days there would be no end of online resources for this kind of thing. It's going to all depend on how much water power you get reliably and how much electric power you need.

I have an old book "Producing Your Own Power", Rodale Press, 1974 dealing with some aspects of water power. Bound to be plenty of resources out there.

Hint: You really, really need some elevation change.

Best of luck

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

how much power can you extract from fast flowing water ?

Is it better to duct the water to some height ?

How much power do you need ?

diameter ? I wonder why the diameter is usually pretty much the same as the height (between inlet and outlet) ?
Why not "undercut" the wheel ? Have the diameter 2*height (so the axle is conveniently at "ground", = outlet, level) ?
It is no doubt all very complicated, about how much power you get, rotational inertia, etc.

but at least we've had water wheels for long enough that we should understand them well !?

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

stevepoxy456, check the link.

For a start, I'd ignore everything above the DOE entry.

The problem with sloppy work is that the supply FAR EXCEEDS the demand

This might be a good reference
Gravity water wheels as a micro hydropower energy source: A review based on historic data, design methods, efficiencies and modern optimizations

The starting point with any analysis to determine what you have, i.e., how much vertical drop, if any, and how much volumetric flow you have, since these determine how much mechanical power is present in your stream. Of particular note is Figure 1 from the article

TTFN (ta ta for now)
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What an excellent, interesting, chart. Is there any other concept (extract power from moving fluid) that has so many different solutions?

Cheers

Greg Locock


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What you're talking about is called micro hydro. There are books and other resources about it. Fortunately the technology is fairly mature, so books from the 70s are very much in play.

Take great care with the regulatory side of it. Unlike the recent Clean Streams ruling, micro hydro is set up on consistently moving water and therefore fully subject to all regulatory considerations.

Said another way, if anyone who bordered a stream was allowed to build a dam and harvest power, I think we would see much more of it. So do your research there too.

First, do a bit of searching on this site - this issue has come up many times before and as said there are a variety of YT videos and people building similar things.

one thing to realise is that what you're doing is simply converting one form of energy into another. So understanding what the energy is in the wate ris your first understanding / realisation before moving onto how to convert that to usually some form of rotary action to which you can try and extract electrical power.

"Small water wheels" isn't very clear. Do you mean taking water from one height down to different height? In which case you usually need a dam or simialr sudden drop ( water fall) to make it happen.

Fast flowing water? Actually very difficult to do anything useful and usually needs to be channeled into a narrow trough.

Debris, fish, branches, rocks are all a hazard which can break your machine.

Small scale especially has a lot of losses in it so the theoretical energy vs what you can actuallg get out of it can be orders of magnitude apart / very low "efficiency"

Just try typing in "gravity water wheels" and all sorts of useful stuff comes up like this https://www.alternative-energy-tutorials.com/hydro...

I get an idea for a "stream" you're looking at an undershot wheel - note in the link it says they are really quite inefficient.

But this linll looks to me like exactly what you're trying to do? https://www.builditsolar.com/Projects/Hydro/FlowOf...

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

Quote (LittleInch)

one thing to realise is that what you're doing is simply converting one form of energy into another. So understanding what the energy is in the wate ris your first understanding / realisation before moving onto how to convert that to usually some form of rotary action to which you can try and extract electrical power.

Valuable point. Said another way, hydropower comes from the momentum of the moving water and from the head pressure that comes from its built-up weight behind a dam. That chart essentially shows the optimal solutions to harvest the water's energy based on their proportion and absolute quantity of momentum and head pressure. The highest efficiency comes from high head conditions, which aren't available to ordinary folks. Harvesting energy from shallow flowing water is less efficient but still possible.