Gravitation water vortex power plant

[nitrogen]

Microhydroelectric has come up on HN before: https://news.ycombinator.com/item?id=6895582

This open design looks interesting, but there are a couple oddities in the Wikipedia article I'd appreciate clarification on from a subject matter expert:

>It was first patented by Greek-Australian Lawyer & Inventor Paul Kouris in 1996[1], who was searching for a way to harness the power inherent in a vortex.

What power is inherent in a vortex apart from gravitational potential energy being converted to kinetic energy?

>after a year of use its operation cost was approximately one US dollar per Watt capacity of output.

Shouldn't that be installation cost, not operating cost?

[btrettel]

Fluid dynamicist here. Your understanding is correct. I would not read anything into vague statements like "the power inherent in a vortex". That explanation is basically woo. There's nothing special about vortices. The large vortex used here is sustained by the gravitational potential energy, as you said.

The Wikipedia article read a bit like an advertisement to me.

I don't suspect the Coriolis force of the Earth contributes much to this turbine either, though I admit I don't know much about the Coriolis force in fluid dynamics. For objects of the size shown, Coriolis forces are neglected in my experience.

Edit: Wikipedia backs me up on the Coriolis force being negligible. Aside from starting the rotation in the cited tests (something needs to break the symmetry), the Coriolis force is negligible compared against gravity. In the turbine case I believe turbulence would break the symmetry (the turbulence itself being influenced by imperfections in the flow, surfaces, vibrations, etc.).

https://en.wikipedia.org/wiki/Coriolis_force#Draining_in_bat...

[komali2]

Re: vortex, reminds me of in "Echopraxia" a bunch of monks powered their monastery with a trapped tornado. No idea how feasible that is but it was badass.

[pwg]

> >after a year of use its operation cost was approximately one US dollar per Watt capacity of output.

> Shouldn't that be installation cost, not operating cost?

Since the Wikipedia article does not say, we can not be sure. I interpreted that sentence to intend to describe the long term operating costs without consideration of the up-front installation costs (which obviously will inflate the actual long term operational costs if installation costs were amortized over the lifetime of the unit).

[lumberingjack]

I have one of these on my property the previous owner built it. It takes quite a bit of maintenance to keep working properly, every 3-4 days I have to hike up the trail 15 mins to clear debris. If it rains then I have to clear that day. Also it is sorta scary, it's basically a drowning machine a few years ago I had to build a cover for it to keep wildlife from getting trapped. One of the best things I like about it is that it doesn't seem to effect fish any they come and go up and down stream freely.

[8bitsrule]

Usages are comparable to a hydraulic ram (which has been around for a long time). Probably less expensive because of the simplicity. Clever. https://en.wikipedia.org/wiki/Hydraulic_ram

"The hydraulic ram is sometimes used in remote areas, where there is both a source of low-head hydropower and a need for pumping water to a destination higher in elevation than the source."

[princekolt]

I wanted to mention hydraulic rams too! I think they're easily one of the most ingenious and clever mechanical devices ever invented. It's too bad they're not practical for large scale systems.

[cagenut]

here's a good 2m30s youtube that shows 15kW one in action: https://www.youtube.com/watch?v=gY3p2e1-kN4

its amazing how little there is to it, and how relatively quiet it is.

[exabrial]

Interesting, this is a bit different design... it appears water has to "fall through" that turbine, rather than using the "stirring force" per the wikipedia article.

[oneplane]

It's pretty cool so see a combination of manufacturing, installation, and operation. For a distributed power grid this might be a clever addition, add some solar, wind and perhaps battery-backed buffer and emergency fuel-powered generator and you might have yourself a pretty reliable self-sustained power source. I imagine out of those, the wind one might need the most maintenance, or if a lot of crap comes down, the solar panels need periodic cleaning. I wonder what maintenance this generator needs, besides the obvious stuff (brushes? lube on contact points? bearings?).

[tajen]

Just for an order of magnitude, even if it’s not the same usage:

- One nuclear core: 700MW - Or 50.000 of those microhydraulic turbines.

[ConcernedCoder]

I don't think there's any more water power being converted into rotational force ( via the vortex ), then there would be using any number of conventional [water turbine](https://en.wikipedia.org/wiki/Water_turbine) designs, like those used at, for example, the [Hoover Dam](https://en.wikipedia.org/wiki/Hydroelectricity).

[usrusr]

Once you remove the inhabitat.com-style magical thinking (coriolis, vortex), the main selling points are being fish-friendly and that all the technological bits are in a single package conveniently accessible above water level.

[feedbeef]

A couple more interesting things come to mind:

https://en.wikipedia.org/wiki/Tesla_turbine

https://www.youtube.com/watch?v=mrnul6ixX90

https://en.wikipedia.org/wiki/Tesla_valve

Also see: Viktor Schauberger (caution: will take you down quite a rabbit hole).

[siliconunit]

wow, definitely a rabbit hole! the whole Schauberger family it seems.. interesting stuff, thanks!

[mannykannot]

In general arrangement, it looks rather like a downsized, simplified Francis turbine.

https://en.wikipedia.org/wiki/Francis_turbine

[Piezoid]

You're right. The main selling point of both turbines is the axial flow: the velocity differences between the water and the blades are the same on every sides of the turbine. The shear forces are low enough to let wildlife pass through unharmed (supposing that it's not heavily torqued by a high electric loads).

[cybrox]

This has been around in Switzerland for a while. Sadly, the company running it (the first of its kind here) went bankrupt

https://www.srf.ch/news/regional/aargau-solothurn/wasserwirb...

[hbk1966]

With such a drop required could you harness a tide to produce power. Like maybe allow the tide to fill San Francisco Bay and harness it when it recedes.

[mkagenius]

Can someone hint why this is different from the usual stuff like falling water on turbines? Perhaps this is more efficient?

[alexchamberlain]

Stupid question time: could this be used in sewage systems or similar to generate energy from us flushing the loo?

[UncleEntity]

Back in '95 or so I saw someone who used an old turbo (well, half a turbo) to the same effect during a field trip in one of my "appropriate engineering" classes. I guess it was (is?) enough of a thing they figured out the formulas to size the turbo vs the water head &etc.

Much smaller scale but along with a little solar and a little wind they were 100% off the grid.

[gweinberg]

I'm dumb as a post, I can't understand why some fancy vortex thing will get you more power than an ordinary water wheel.

[jarfil]

A water wheel can not have more than 75% of the blades in contact with water at any point (or it would slow it down) and it is rarely practical to have more than 30% of the blades in contact with water.

A turbine in a vortex has 100% water-blade contact all the time, which means it can transfer more power with a smaller size and cheaper materials.

[bencompanion]

A well designed waterwheel could be pretty efficient in these cases, too. Waterwheels tend to lose out when hydraulic head (water drop distance) is too big to construct a practical wheel.

As other people have said, the advantage here seems to be that you get a high rotation speed out of a low hydraulic head. A waterwheel in this case would have lower RPMs, and so require more gearing etc. to be efficient for power production.

In general, turbines are preferred because the moving parts are smaller - rather than having a massive spinning wheel, you just let gravity provide the water pressure, and have a much smaller turbine blade do the spinning.

[GoToRO]

And you can use it as a washing machine https://www.youtube.com/watch?v=akJ9Zo5hhM8

[m3kw9]

Seem cheaper and less complex + maintenance with solar.

[martyvis]

But with solar you only have maybe 10 hours of generation per day at best, so you need to store the energy ( which has inefficiencies) or a grid that can cover many timezones. Using stored water for potential energy means it can be turned on and used as needed, and rated for an average use. In Australia there are plans for more stored energy systems using pumps and generators, probably fed by solar and wind.

[odammit]

We used to make these in our above ground pool when I was a kid by running in circles.

[gigatexal]

73% sounds really efficient. How does it compare to other power plants?

[ginko]

Large hydroelectric plants can apparently have efficiencies of over 90%[1]. Smaller ones somewhere between 80% and 90%.

[1] http://www.mpoweruk.com/energy_efficiency.htm#comparison

[peter_retief]

This is so weird, I had a dream 2 nights ago of this very thing, a steady state hydrocyclone that had a steady state net power output and clean water!!