# Pressure Harvesting - from ocean depths

I have read that abandoned iron smelters can make excellent giant batteries. Their construction is easily convertible to electric storage purposes.

Obviously not.

What I deny - and this has now been said you five or six times, by at least four different people but seems not to have got through - is that you can do this without expending as much energy in the process as the energy you obtain.

So it is NOT a source of energy.
Just to clarify this point:

say we have a variable volume pressure vessel that is cylindrical about 1000 meters long with an inside diameter of about 50 meters.
It's big ok...made of iron and weighs heaps.
It is weighted down with the appropriate weights ( rock or iron who cares hey? Money for this experiment is not a problem...)
It has a hose attached of the necessary length that ports the pressure side of the vessel.
The hose has a tap on it on the surface.

The cylinder is then released and allowed to sink rapidly all the way to 3000 meters trailing the hose above it.
It hits the bottom and has about 35000Kpa of pressurized air inside it. Remember it is a variable volume pressure vessel.

ok any questions at this point?

when we release the hose tap on the surface what do we get in the way of air pressure...?
35000 kPa or nothing?

Last edited:
so a hose attached to the Variable volume pressure vessel down at depth, with say 35000kPa of pressure inside it would not provide 35000Kpa at the surface?
Not as part of a repeatable cycle, no.

You could obviously sink a heavy container with air in it, let the water compress the air, and then get that air out of a hose at the surface. But then you've lost your container.

To get it back and repeat the process (and I have told you this about four times now) you have to pull the thing up. Which takes at least as much energy as you got from the compressed air.

Just to clarify this point:

say we have a variable volume pressure vessel that is cylindrical about 1000 meters long with an inside diameter of about 50 meters.
It's big ok...made of iron and weighs heaps.
It is weighted down with the appropriate weights ( rock or iron who cares hey? Money for this experiment is not a problem...)
It has a hose attached of the necessary length that ports the pressure side of the vessel.
The hose has a tap on it on the surface.

The cylinder is then released and allowed to sink rapidly all the way to 3000 meters trailing the hose above it.
It hits the bottom and has about 35000Kpa of pressurized air inside it. Remember it is a variable volume pressure vessel.

ok any questions at this point?

when we release the hose tap on the surface what do we get in the way of air pressure...?
35000 Kpa or nothing?
See post 163.

Not as part of a repeatable cycle, no.
no mention of repeating the cycle... the vessel is abandoned. Money is not the object...who cares?
You could obviously sink a heavy container with air in it, let the water compress the air, and then get that air out of a hose at the surface. But then you've lost your container.
absolutely lost it, but you have also managed to exploit the ambient pressure converting it to potential energy via air pressure at 35000kPa.

so to state it clearly:
Deep ocean pressure can be exploited for potential energy.

Wasn't that hard was it?

no mention of repeating the cycle... the vessel is abandoned. Money is not the object...who cares?

absolutely lost it, but you have also managed to exploit the ambient pressure converting it to potential energy via air pressure at 35000kPa.

so to state it clearly:
Deep ocean pressure can be exploited for potential energy.

Wasn't that hard was it?
What you have done is trade the loss in gravitational potential of the vessel for the energy in the compressed air. This you can obviously do. But what you cannot do is use this as a practical energy resource. I remind you what you said in post 1 of this thread:

Ample resource
No waste product

Average depth of the oceans is about 3600 meters
At this depth the pressure is 36000kPa (360 atm or 5263 psi)

What could you do with an endless supply of 36000 kPa?"

This is what I and everyone else have been telling you cannot work.

P.S. But it is progress that you acknowledge this idea of "harvesting" is impossible - except in the sense of a combine harvester with no engine that works one strip to the bottom of a field by gravity, and then has to be left to rust for eternity. Not many people would call that "harvesting".

Wasn't that hard was it?

What you have done is trade the loss in gravitational potential of the vessel for the energy in the compressed air. This you can obviously do. But what you cannot do is use this as a practical energy resource. I remind you what you said in post 1 of this thread:

Ample resource
No waste product

Average depth of the oceans is about 3600 meters
At this depth the pressure is 36000kPa (360 atm or 5263 psi)

What could you do with an endless supply of 36000 kPa?"

This is what I and everyone else have been telling you cannot work.

P.S. But it is progress that you acknowledge this idea of "harvesting" is impossible - except in the sense of a combine harvester with no engine that works one strip to the bottom of a field by gravity, and then has to be left to rust for eternity. Not many people would call that "harvesting".
To me it poses an interesting observation.
Actually there are two issues of gravity at work. (I am not sure of the terminology)
One acting on the cylinder and one acting on the water (to grant ambient ocean pressure).
One aspect of gravity is working against another aspect of gravity. The end result is the potential energy of the compressed air.
Standard gravitational potential of the vessel (3000 meters in height and falling)
+
The gravitational potential of water at 3000 meters deep.
I see it as vertical and horizontal forces or vertical and omni directional forces
Sorry but it is just me rambling...

Sorry but it is just me rambling..
No no no..look your idea is fantastic, don't listen to anyone, just go out and build one and make billions.
Alex

No no no..look your idea is fantastic, don't listen to anyone, just go out and build one and make billions.
Alex
Nah! The principle if founded properly might lead to something...a tad more clever maybe... lol

Could we harvest water off a duck's back?

Could we harvest water off a duck's back?
would that be before or after it got wet?

It is a bath duck; tap is on permanently. We can take Coriolis force into consideration but this is not an Antipodean setting.

To me it poses an interesting observation.
Actually there are two issues of gravity at work. (I am not sure of the terminology)
One acting on the cylinder and one acting on the water (to grant ambient ocean pressure).
One aspect of gravity is working against another aspect of gravity. The end result is the potential energy of the compressed air.
Standard gravitational potential of the vessel (3000 meters in height and falling)
+
The gravitational potential of water at 3000 meters deep.
I see it as vertical and horizontal forces or vertical and omni directional forces
Sorry but it is just me rambling...
I suppose that's right, in the sense that something has to do work to force buoyant air down into the depths of the sea, where the sea can compress it by its weight. And that something can be either an externally applied force or the force of gravity on a heavy object that outweighs the buoyancy.

It is a bath duck; tap is on permanently. We can take Coriolis force into consideration but this is not an Antipodean setting.
Is this you trying to get on the same wavelength as Quantum Quack?

One interesting thing unexpected was to realise that water at depth has an omni-directional gravitational potential ( pressure). If that is the right terminology...
That is to say that at any point in body of water the force of gravity is more omni directional than vertical.

Perhaps too trivial but then again...

Last edited:
One interesting thing unexpected was to realise that water at depth has an omni-directional gravitational potential. If that is the right terminology...
That is to say that at any point in body of water the force of gravity is more omni directional than vertical.

Perhaps too trivial but then again...
Sort of, yes. Because water is a fluid, the weight of the water above a given depth acts in all directions, causing what we call hydrostatic pressure.

Whereas the pressure of a rock on top of you acts only vertically downwards and depends on both its weight and its surface area.

Sort of, yes. Because water is a fluid, the weight of the water above a given depth acts in all directions, causing what we call hydrostatic pressure.

Whereas the pressure of a rock on top of you acts only vertically downwards and depends on both its weight and its surface area.
So you know quite a bit about fluid mechanics?

Whereas the pressure of a rock on top of you acts only vertically downwards and depends on both its weight and its surface area.
or the water on your back....

So you know quite a bit about fluid mechanics?
Far from it. This is old A-level physics (from about 1970, in my case ).