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sharpener wrote: ↑Wed Nov 27, 2024 11:27 am I hope they have tested a model of this in a tank. I ask myself why the tidal race would bother going into the spiral rather than flowing gracefully past the whole thing.

A true Archimedes Screw is a positive displacement turbine turned by the weight of the water in the pockets formed by the spiral. Quite different.

Tidal and wave power have come up with many weird and wonderful ideas over the years. The underlying issue is that making the machines strong enough to withstand storm conditions makes them many times more expensive to construct than what is actually needed to generate the power, so the capital costs per kW are huge (or they fail catastrophically in the first storm).

AE-NMidlands wrote: ↑Wed Nov 27, 2024 11:47 am
What would be a goer using seawater (albeit small scale) would be Archimedes screw generators at the sites of the old watermills on the NW coast of Kefalonia where the seawater disappears under the island, re-emerging on the east coast! It sounds impossible, but it's true!

sharpener wrote: ↑Wed Nov 27, 2024 12:26 pm

AE-NMidlands wrote: ↑Wed Nov 27, 2024 11:47 am
What would be a goer using seawater (albeit small scale) would be Archimedes screw generators at the sites of the old watermills on the NW coast of Kefalonia where the seawater disappears under the island, re-emerging on the east coast! It sounds impossible, but it's true!

Sounds interesting, have you got a link? Don't quite understand how there is a difference in level to operate an Archimedes screw.

When I retired to S Devon I had an idea to catalogue the many former mill sites to see if any were worth encouraging to re-power with modern machinery. But it turned out someone had already done it ?U of Plymouth project?. Nothing has actually been built AFAICS.

There is a twin Archimedes screw installation on the R Dart, mentioned in an earlier thread https://camelot-forum.co.uk/phpBB3/view ... 743#p51743.

Tresoc were going to do another at an old mill at Staverton https://tresoc.co.uk/project/stavertonhydro/ but the idea was scrapped bc of fears for migratory salmon, despite many other examples of fish passes being successfully installed e.g. at Buckfastleigh, or Pitlochry which we visited 2 yrs ago. (The whole post WWII Tummel scheme https://en.wikipedia.org/wiki/Tummel_hy ... wer_scheme was extremely impressive and I had no idea about it previously.)