The thing is - I want to make this thing as little obtrusive as possible. The river is right in the middle of a neighborhood, and I can’t have to muncipality-people coming over and giving me trouble… A pelton-setup would be easier to make compact and “hideable”.
Another option that I was considering intitally (but quickly gave up because of low efficiency) is some kind of water screw setup. Such a turbine can be made quite long, and not as noticeable. Unfortunately, I’m not sure if it’ll be efficient at all…
Make it decorative. It’s not uncommon to see “fake” water wheels over here, with a hidden pump recirculating the water. In your case, no pump needed. Power a few decorative LED yard lights to satisfy those who may ask a few more questions, without revealing the actual generating capacity of your system.
Actually not a bad idea! The wooden wheel I made would be both decorative, but have plenty of spinning force. It’s only that I’m afraid of the kids in the neighborhood, who’ll definately stick their arms into any place intriguing enough… hum hum… I’m going to check with a plumber friend about different types of piping to lay down. We’ll see
I wonder if I put 2-3-4 lengths of 10-15 meter of these pipes dug into the stream floor, and joined them - that would give me a quite decent amount of water. Not sure about the pressure, but the amount of water should be decent - it has to be seen what I could make with a nozzle.
The cheapest tubes would be cable tubes. Unfortunately, they are always corrugated. What do you think, would it slow the flow too much?
While I do understand your concerns about neighbors, city and other annoying people, I don’t want to discourage you but it’s very likely you won’t go anywhere with those tubes. 2 or 3 meters max with this kind of flow will give you miserable results. I’d say don’t expect more than 5 watts. Also this kind of tube isn’t smooth, so you get lots of internal friction from the water, evellowering its efficiency.
It’ll be disappointing especially given the costs you’ll have invested into tubes, turbine, your time and whatnot.
The idea of making a nice looking “decorative” wheel is nice and sneaky, I love it.
Or the other way, making it dirt cheap, like a proof of concept, install it for a few months, see if any annoying dude shows up. If not, make it look better and more durable. Maybe you live in a nice city with decent neighbors, who knows.
Now joking aside, there are several companies that sell so called hydrokinetic turbines (or just river turbines) that can be dropped into a stream and will be completely submerged. These are more useful in fast flowing deep rivers though so this idea is unlikely to work. Google did not find a DIY version so it’s probably not that easy to make either.
An interessting video of a tech which might apply very well in your case. Plus it’s probably easy to build if you own a 3D printer (or if you are a bit creative, there are other ways too.
They don’t really say how much power this thing can output. M y guess is that it is quite low since there’s no free lunch here and everything depends on flow x height, but at least it’s portable, you can build several of these and it might be a fun experiment.
I think also that the technique of using sand bags for making a small temporary dam for cheap is quite simple yet very clever.
Came across these the other day. They are 50mm wide and 6m long. If I had three pipes, 6 or 12 m long, embedded in the river bed, I’d get 2-3m height. Don’t know if it’s enough for a nozzle…
