"Kinetic Hydro"

[AE-NMidlands]

https://kinetic-hydro.com/technology/ offers a 380W run-of-the-stream generator and claims 9kWh per day. I have no idea of the price they are asking. My son is moving to near there and has indirect contacts so I might ask what he can find out about it.

If you had a stream would that be a useful little thing to have, or is it another chocolate teapot?
My pv is doing over twice that at the moment so I'm happy without a stream, but I suppose if you lived in a deep narrow valley which didn't get any sun it might be better than nothing...

[Joeboy]

That is kinda clever in that any shoreside building reduced to one big riverbed spike midsream. For a full offgrid setup it would be very handy.

I assume flat pads for feet and you'd load down with boulders or is fully floating? Nope its a floater! Surface debris, hmmn. I still like it though.

[Stig]

I wonder if that avoids all the hassle of being required to have an "abstraction" licence for hydro (even though you put all the water back in again). Could be a game-changer for small scale hydro (if it's reliable and cost-effective etc.).

[GarethC]

I know the founder well. Lovely chap and very smart. Iirc he says the biggest issue is getting permission to install. They did a trial install up in Fort William using the aluminium factory outflows.

[Marcus]

It looks 'plausible' and I can confirm that 380w coming in 24/7 is very useful.

But (looking at the smaller unit):

it requires 2.5m/s flow and a depth of 0.5m - that's quite a large, fast stream: if your stream is 1m wide and 0.5m deep (and rectangular), that's 1.25 m2 per second. I suspect that even if you have a stream that fits the bill, you would be much better off (more power) with an archimedes screw. Most of the streams I've looked at for folks asking about hydro power, have either much less water volume but have the speed (like mine), or they have the volume to fit that machine, but are much slower moving (less fall).

So whilst it may have some sort of niche potential (some power with less damage & disruption to the river ecosystem than a screw), I would tent to think of it as a

[Stinsy]

The only thing I know about hydro is that you need a big drop. Eg 5-10m.

Lots of people think that the lazy stream running through their property can provide usable power but it simply cannot.

[MikeNovack]

The only thing I know about hydro is that you need a big drop. Eg 5-10m.

Lots of people think that the lazy stream running through their property can provide usable power but it simply cannot.

You do not need a big drop. But what you do need is a big product, drop x flow. The ratio of flow to drop determines the "specific speed" of the device needed, and so the type of device. A few types do not have a well defined specific speed. For example, if the axial size (compared to diameter) of a cross flow turbine is undetermined, so is the specific speed (the old overshot wheel the same)

Here in an application where flow speed used, you can think of that directly equivalent to the drop that would result in that speed.

And no, not an "Archimedes screw". Here the correct is being used, an "axial flow" turbine of fixed pitch (non-Kaplan) type. Specific speed of this type >100. Somewhat better would be a pair of contra-rotating coaxial props.

[smegal]

This device is more like a wind turbine than a hydro turbine. The below equation discusses how much energy is present in a given area. There is then an "efficiency" limit of how much energy you can extract from the moving fluid (theoretical limit is around 60%).



The density of water is ~816 times higher than air.

[MikeNovack]

This device is more like a wind turbine than a hydro turbine. The below equation discusses how much energy is present in a given area. There is then an "efficiency" limit of how much energy you can extract from the moving fluid (theoretical limit is around 60%).

Yes, about ~58% IF the "area" is defined as the area swept by the rotating blades. Saying "more like a wind turbine" not as meaningful as you might think. The only real issue is in one case the fluid compressible and in the other, not (in one case you don't need to worry about "cavitation" and in the other, you do)

The same sort of limit doesn't affect the usual hydro turbines of certain types because for reaction turbines, most of the energy lost getting water out of the turbine can be recovered in a suitable draft tube AND the amount is usually small in the typical impulse turbine* (but it's the main reason why not closer to 100%).

* Because NOT "full" and the area of outflow much larger than the area of the inflow, so the outflow velocity << the input velocity (and energy goes with the square of the velocities)

[Stinsy]

The only thing I know about hydro is that you need a big drop. Eg 5-10m.

Lots of people think that the lazy stream running through their property can provide usable power but it simply cannot.

You do not need a big drop. But what you do need is a big product, drop x flow. The ratio of flow to drop determines the "specific speed" of the device needed, and so the type of device. A few types do not have a well defined specific speed. For example, if the axial size (compared to diameter) of a cross flow turbine is undetermined, so is the specific speed (the old overshot wheel the same)

Here in an application where flow speed used, you can think of that directly equivalent to the drop that would result in that speed.

And no, not an "Archimedes screw". Here the correct is being used, an "axial flow" turbine of fixed pitch (non-Kaplan) type. Specific speed of this type >100. Somewhat better would be a pair of contra-rotating coaxial props.

Loads of hydro projects have fallen on their face because they believed that!

The truth is that hydrodynamics is WAY more complex than you might think. The "underwater wind turbine" designed can indeed generate usable power in tidal applications when scaled up. However the realities of a marine environment mean: super-high installation costs, short lifespans, and frequent breakdowns. This makes it not economically viable for anything other than fleecing governments of huge research grants.

Small-scale, it just won't work.

The old fashioned overthrown wheels all had a significant drop (5-10m in all the ones I've seen) and they usually had a "millpond" that stored water over several days/weeks to be used for a few hours of milling.