Turbulent hydro

[Moxi]

Billi

I hear you, the low head limits the energy extraction options but it should not be impossible.

From what I understand the under shot wheel creates its head between the front (head race) and back of the paddle (tail race) and this is measured in tens of millimetres only so it’s the best option for you at the end of the village as you don’t want to cause levels to back up upstream and create problems for neighbours.

1m/s isn’t much but it’s something so you need to see how you transfer that energy for the best output.

Why not make up a wooden eight spoke wheel and attach the bottom of a plastic milk bottle cut to the shape of a cup to each spoke and drill a central pivot for a rod or pole to act as a shaft then lower it so the bottom cup is pushed by the flow, you can get an idea of the speed of rotation - larger diameter wheels slower rpm more torque smaller diameter faster rpm less torque. You can also gauge the torque just using your hand to slow or stop the wheel to get and idea of the driving force you could expect.

If the results are poor then you’re probably out of luck if they’re promising then slap on some magnets at the rim and mount a copper coil at the top and see what you get open circuit and if that’s not bad then start putting on some loads to see how that affects rotation. Even better if you have an Ebike motor hub spare?

Maybe doing this sort of experiment with an old bike wheel may be easier and yield better results ? The thing is you can learn more by getting in the stream experimenting than any other method. One unit may not give you everything you need power wise but if I understand things correctly you can mount any number of undershot wheels as long as you leave three diameter length equivalent between rims.

Moxi

[billi]

[Maybe doing this sort of experiment with an old bike wheel may be easier and yield better results ? /quote]

exactly what i thought about this morning ....as there are at least 10 bikes in the shed