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New water power, 'reverse" archemedes screw from Germany and gravitational vortex from Austria

I think the gravitational vortex is a few years old and I only found the Reverse Archemedes Screw yesterday.
Would anyone like to do instructables on them? It seems both are attempts to make hydroelectric power a bit more fish friendly.  They say the reverse archemedes screw is very efficient too.
Check them out and see what you think.  I put videos about them in this playlist
http://www.youtube.com/view_play_list?p=FD3B655FED590244
While I am here, why do the screws shown not have the auger and shell of the screw all welded together? Perhaps it is just for cleaning reasons?  Or maybe it is just  too difficult to make a "spiral staircase" inside a pipe?
Anyway, it looks like excellent projects for someone.   The reverse archemedes screw is totally new to me.
I have seen videos of the austrian system before.
If they are fish friendly, lets make them popular. One question, how do the fish migrate up the river?
Brian


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lemonie7 years ago
Hi,

  The screw doesn't need the steel outer in it's concrete trough, as you suggest - not at all worth the effort of making it in a full tube.
W/ref the fish, there will be a tap-off from the river, only part of the water flow is going down the screw.

L
gaiatechnician (author)  lemonie7 years ago
Thanks.  but I just letting people know that for their experiments, the spiral in a tube is an option.
In the big commercial ones, the leakage and friction might be minimal between the screw and the concrete.  For the amateur making a model with something like 8 inch plastic pipes, (that might bend a little under the weight of the water), leakage and friction will be proportionally much greater.
it might be an option to attach a screw made from light plastic material to the inside of the pipe itself  and have the whole pipe rotate. 
It is an interesting problem. Also, if you make the screw independent of the pipe, it must be of much finer stronger construction and heavier too.
But if you  attach it to the inside, what is the best way to attach it? (because you do not need leaks) The pipe with its insides attached can be a fully portable system, 
Just a thought.
gaiatechnician (author)  gaiatechnician6 years ago
Just a reply for me and Lemonie. They have done the plastic full tube as I described in the United Kingdom. Lemonie said it could be done too!
Is nobody willing to try this?
It is at

I watched the video: it was that screw I was referring to. Yes, I agree the full tube is easier to take to site and install, and for something small you could injection-mould the screw & glue it into an outer. Amateur-build not so easy, but easier than e.g. a Pelton-wheel perhaps?

L
gaiatechnician (author)  lemonie7 years ago
I guess the reason these "slow" electricity generators are even possible nowadays is windturbine technology? 
Back 20 years ago, it was rapid spinning things like the pelton or nothing.  Gearing up a waterwheel (at about  60% efficiency) meant another  15% of the energy was gone. 0.6 X0.85 gives 50% efficiency before you even convert it to electricity.
They said about 90% efficiency for the reverse archemedes screw!  Thats amazing on a low head site.
I certainly hope people make models of this. Just to let the people here in North america know that the option exists.
I think a pelton needs more head to spin it. And probably it needs very clean intake too.
Koosie7 years ago
While I don't know much about the Reverse Achremajiggy Thingy, I have heard about the gravitational vortex turbine.  Saw it on some Green website, Tree Huggers .com I think.  Anyway, I agree with you, an 'ible for it would be nice.

Clever idea to generate electricity and oxygenate the water.