Tide Generator

[Some dude]

This is not my idea, but one of my friend thought of it, and it sounds like it would work.

The idea is you have some massive metal tube stretching from the sea floor. A metal pole would be inside the tube, and the pole would be strapped to a buoyant object. As the tide rises/lowers, it would move the pole like a piston.

 

The friend didn’t suggest how exactly the energy would be created, and I’m too dim witted to figure that out... but yeah. 

[exchemist]

8 hours ago, Some dude said:

This is not my idea, but one of my friend thought of it, and it sounds like it would work.

The idea is you have some massive metal tube stretching from the sea floor. A metal pole would be inside the tube, and the pole would be strapped to a buoyant object. As the tide rises/lowers, it would move the pole like a piston.

 

The friend didn’t suggest how exactly the energy would be created, and I’m too dim witted to figure that out... but yeah. 

It would generate energy, yes, but very little. What this device would do is displace a volume of water equal to the area of the pipe x the tidal range, once every 12hrs, so it would be a sort of very slow pump.

To extract energy from the tides, you are far better off to use a place where a natural restriction, say the entrance to a bay, causes a significant tidal current and then use a turbine of some kind. That way, you exploit the tidal displacement of an entire bay's worth of water volume every cycle. 

[pzkpfw]

Some info (i.e. it's been done (in ways)):

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

[Ken Fabian]

11 hours ago, Some dude said:

This is not my idea, but one of my friend thought of it, and it sounds like it would work.

The idea is you have some massive metal tube stretching from the sea floor. A metal pole would be inside the tube, and the pole would be strapped to a buoyant object. As the tide rises/lowers, it would move the pole like a piston.

This would be a wave generator, not a tidal generator.

Rather than a piston but working along these lines... I've encountered - systems where air is drawn in and pushed back out past a turbine as waves pass.

Also the use of the cables of a buoyant object aka a buoy, reeling in and out and driving a generator.

 

Edited June 23, 2021 by Ken Fabian

[dimreepr]

45 minutes ago, Ken Fabian said:

Rather than a piston but working along these lines... I've encountered - systems where air is drawn in and pushed back out past a turbine as waves pass

A piston requires a push...

[Ken Fabian]

10 hours ago, dimreepr said:

A piston requires a push...

Push or pull, pressure or suction, either way can do that - the earliest steam engines sucked (from steam condensing in the chamber) rather than blew; depends on the design whether such a piston would push or pull. It would work either way. I note that my bicycle pump pumps air both pushing and pulling.

But what is the piston connected to? A crankshaft like a reciprocating engine? Or will it pump air, say, through a turbine? The first example above ditches the piston and uses the water column itself as the piston to pump air past a turbine - much simpler.

The second example could have wave motion pull up some kind of piston in a cylinder in place of the reeling of cable in and out - closest to the OP suggestion that way - with the same question of what then? It could pull up a piston in a cylinder but it looks like there is no advantage; a whole lot of engineering issues are sidestepped by not using pistons.

I also note that hypothetically such things could be driven by tide rise and fall - just very slowly and delivering very little power.

Edited June 24, 2021 by Ken Fabian