Using the Pressure of Water and Rising Bubbles to Produce Energy

"This is the same principal that keeps a boat afloat."

No, it isn't.

An object will float if the gravitational (downward) force is less than the buoyancy (upward) force. So, in other words, an object will float if it weighs less than the amount of water it displaces. This explains why a rock will sink while a huge boat will float. The rock is heavy, but it displaces only a little water.

Bubbles won't make boats float. They reduce the density of water.

How Do Boats Float ? | Wonderopolis

This concept is completely DOA.

I expect most salvage divers are already intuitively aware of how to lift an object with air from a scuba tank.

What you may not realize is a hazard in this process is every balloon has a maximum volume it can achieve before it breaks. One single balloon that breaks before reaching the surface will frequently cause the entire payload to fall back to the lake/ocean floor.

If not; this is a dead horse with nowhere to go.

Sorry, I think you will find after a little more examination of this buoyancy idea that your dead horse will just float to the surface.

No free lunch here with this particular conceptual energy proposal.

Dead horse:

• Where does the power come from to generate <...300 cubic feet of air compressed to 18 ATM...> (rhetorical question - NNTR)?

The statement <...This is the same principal that keeps a boat afloat...> is nonsense, as well as incorrectly spelled.

"Getting something for nothing" is a fundamentally unavailable concept within this universe. If it weren't, then it would spontaneously explode and cease to exist.

The question is; is this possible, do the numbers add up?

It takes (X) amount on energy to fill one balloon with air at 18 ATM

That balloon rises and another balloon attached to the first is injected with (X) amount of air (X1)

That balloon rises and another balloon attached to the first is injected with (X) amount of air (X2)

That balloon rises and another balloon attached to the first is injected with (X) amount of air (X3)

That balloon rises and another balloon attached to the first is injected with (X) amount of air (X4)

That balloon rises and another balloon attached to the first is injected with (X) amount of air (X5)

now you have five (5) balloons attached to each other pulling together creating more lifting force than it took to fill the first one

(X)+(X)+(X)+(X)+(X) has a greater lifting force than (X)

Divers use this method to lift objects from the sea floor all the time, so of course there's a calculator for that...

This is an example of air volume needed to lift an object 1000 lbs in weight and 6 cu ft in volume from the seabed 180 ft below......

..."Object in Salt water at 180 ft, weighing 1000 lbs with a volume of 6 cu ft.

A lift capacity of 616.4 lbs or 9.6 cu ft is required.
The lift bag will use 62.2 cu ft of air at 180 ft."...

https://www.divebuddy.com/calculator/liftbag.aspx

So you would need a standard 80 cu ft scuba tank roughly speaking to lift 1000 lbs....cost about $5 for each fill up...doing it yourself with a surface pump and long hose probably cheaper...

https://www.divegearexpress.com/library/articles/calculating-scuba-cylinder-capacities

Now if you could produce a gas at that depth from the seawater itself that would be a way to go...

"Now if you could produce a gas at that depth from the seawater itself that "would be a way to go...

Geothermal vents are generally very deep in the ocean....

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

But a reliable source of heat....where there is heat there is a potential for energy production...

http://www.halfbakery.com/idea/Geothermal_20Power_20from_20Hydrothermal_20Vents

It seems to me to be something that would be prohibitively expensive and problematic, but could in theory be done....

The only thing that is buoyant about this horse is its unbridled optimism.

There are four (4) horses pulling this wagon

Why not just use one horse, when it tires hitch up another, letting the first rest; repeating this process as each horse tires.

At least the mods here have not banned me for gibberish.

On another talk board my fantasy drawing got this response--

"You have been banned for the following reason:

No impossible machines - you still do not understand basic physics of conservation of energy.

Date the ban will be lifted: Never"

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All I can say is thank you mods for letting me talk no myself here.

Kudos to Engineers Edge. Some forums don't even ban or delete outright lies, imputations of mental illness, or improper ad hominem attacks/fallacies.

I’m in such a knee jerk mode I didn’t even read your entire response expecting it to be just another attack, my bad.

I have not looked at this as a means to store energy.

I see it as rather a way to multiply the kinetic force of matter, being the displaced water.

It’s not an attack, it only feels that way...

And since there’s no convincing you on your ‘dream’,... heres a challenge, prove us wrong.

Basically a description of a perpetual motion machine. In the end, it takes more energy to inject the air into the bottom balloon than you get back when it rises.

First, I hate "Not to Scale" drawings. For anyone who uses drawing regularly, such drawings are always misleading. As a minimum, show your bubbles getting larger as they rise, according to your numbers (which I did not bother to verify).

Second, compressing air is an inherently inefficient process, with large losses to heat. That heat kills your horse!

Third, a bubble of any size can only rise when the water above it flows around and then underneath it. That flow wastes more energy, flogging the already dead horse.

Fourth, due to the above flow, bubbles only rise very slowly. Converting that slow motion into any usable form of energy is very difficult, unless perhaps you are dredging the sea floor.

I wonder if the OP has left out some detail or is leaving it to us to apply the concept to something useful or doesn't fully understand the idea he/she has? To me what the OP has done is quantify the mechanics of a float system, nothing more.

If you have this apparatus with 14,4k pounds of buoyancy at a fixed depth tethered to the sea floor somewhere near the coast where there is regular wave action you could take advantage of the rise and fall to harvest wave energy. If the energy needed to maintain constant internal pressure and depth is less than the harvested energy you might have something useful. What is needed is the counter buoyancy mechanism and device for converting the excess energy into electricity.

Alas - none of this is new. Not even the basic idea of using pneumatic balloons. Wave energy harvesting has been around for quite a while.

So - kudos for doing the math and diagram, demerits for not researching prior work. Double demerits if it was researched and copied from prior work.

You are more than welcome to expand on that idea, start a thread.

A gas bubble will expand proportional to the water pressure applied upon it.

The lower the pressure, the larger the bubble expands. This expansion displaces the seawater. For every cubic foot of water replaced with air (gas) the bubble will have a lifting force of 64 pounds.

As the bubble expands its lifting force increases proportionally.

(Y) or (N)

.

No...

Proportionally to what? Diameter, height, area, volume, or something else?

proportional to the pressure of the seawater. The air bubble expands as the pressure gets less. As the bubble expands the lifting force of the bubble increases.

Compare the weight of a cubic foot of water at 1000 ft altitude with a cubic ft of water at sea level....Does the water weight the same?

https://www.nytimes.com/2003/12/23/science/q-a-altitude-and-weight.html

The standard gas equation is PV=NRT, so V=NRT/P. T is likely to rise slowly as the bubble rises. For a given bubble, NR is a very close to constant.

Thus, assuming that the lifting force of the bubble is proportional to the volume of the bubble, and that the pressure is linearly proportional to depth, the liftng force is close to inversely proportional to depth.

Object in Salt water at 90 ft, weighing 1000 lbs with a volume of 6 cu ft.
A lift capacity of 616.4 lbs or 9.6 cu ft is required.
The lift bag will use 35.9 cu ft of air at 90 ft.

Object in Salt water at 180 ft, weighing 1000 lbs with a volume of 6 cu ft.
A lift capacity of 616.4 lbs or 9.6 cu ft is required.
The lift bag will use 62.2 cu ft of air at 180 ft.

As the volume of the air increases so does the drag potentially, the rising rate might hit as high as 100 ft per minute near the surface....nearly doubling in speed...

Increasing or decreasing lifting force (buoyancy) depends on the unstated reference. In other words, is the position (depth) measured from sea floor or surface level.

Proportional

Bubble expands as pressure decreases

Upward force increases as bubbles expand

In my last post, I said: "...the lifting force is close to inversely proportional to depth." (underline added in this post).

You say: "Bubble expands as pressure decreases

Upward force increases as bubbles expand"

Those statements are both correct, and pressure decreases as depth decreases, so Upward Force increases as depth decreases. That's an inverse proportion.

You can make it a direct proportion if you use distance from the bottom, rather than depth.

When divers use this lifting technique they use an open bottom bag to prevent the expanding bubble from rupturing a container. The excess gas during ascent just leaves the bottom of the bag.