Perpetual motion machine?

[bronsin]

I’ve had this idea for a long time, now I want to run it by some people smart enough to know whether it would work.

If you were to lower a sphere 1000 feet deep in the water with a door on it that could be closed when it got down there, it would be pressurized to a great degree.

If you tap into this pressure, would there be enough to raise and lower the sphere with some leftover energy to be turned into electricity?

:iono:

You could have a chain with hundreds of spheres on it in a loop going down 1000 feet below the surface. The door was shut pressurizing the sphere and 1000 feet. When the spheres reach the surface some of the energy could drive the machine that brings the spheres up and down. Would there be enough left over to run a generator?

[sickpuppy1]

the amount of pressure and VOLUME it would take to run a generator would mean the sphere would need to be huge!
Assuming you mean close it while its down there and pressure rises and its brought up?

[NYC-SE]

A perpetual motion machine of any design is impossible as it would violate the law of thermodynamics.

[bronsin]

A perpetual motion machine of any design is impossible as it would violate the law of thermodynamics.

That’s what they say.

But in the 1930s they tested a bathysphere at 1000 feet and it leaked. The hatch was held on with 12 studs and nuts. When they got it on deck they didn’t realize it was pressurized. When they loosened the nuts there were 12 of them when they got to 11 the hatch blew off and went through the side of the ship.

Seems like a way to get free energy if only you could figure out how to do it

[bronsin]

the amount of pressure and VOLUME it would take to run a generator would mean the sphere would need to be huge!
Assuming you mean close it while its down there and pressure rises and its brought up?

That’s right. You could have a circular chain of them I mean pressure vessels pressurized at the bottom of the loop brought to the surface and emptied into a generator. Of course you would need some of the injury I mean energy to run the machine that raises and lowers the spheres to the surface and the bottom

[eTiMaGo]

It's all mathematics really... calculate how much energy you spend lowering and lifting the sphere, how much energy is lost to friction in the chains, pulleys and gearing.

Also a pretty big hurdle: water is incompressible! one cubic foot of water at 1000ft is exactly the same volume at 0ft. The only way this theory *could* work is with a vessel filled with gas, and taken to thousands of feet *above* sea level...

I had a *lot* of perpetual motion ideas in my youth, even tried to build one, an electric motor running a bicycle dynamo, which would power the motor...

[bronsin]

That’s right. It would cost zero to lower to depth, all you have to do is figure out how much energy to bring it up, and how much energy is inside it to do work

[eTiMaGo]

that's the problem, you can't compress a liquid... the only pressure you could potentially have is that cold water is a little denser than warm water. but that difference won't be enough to get any kind of useful energy. This would be similar to geothermal electricity generation, but worse

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

[bronsin]

I guess I don’t understand that. When they removed the hatch of the bathysphere it nearly killed a man because it blew off with Creed force that’s great for us.

Pressure at 1000 feet below the surface of the ocean is 441 psi