It’s technically unlimited. It’s practical value is around 100k psi because of current material physics, but the force grows with volume, also, the more pressure you apply, the higher the temperature, but the more inclined the water is to remain a solid, and you get roughly 10% expansion regardless.
Different states/types of ice exert different pressure under different situations. It can theoretically break any method you could possibly try to use to contain it if the volume is large enough. Ice cracks 10^15 ton mountains wide open on a daily basis It will crack your steel engine block. It will bust open steel pipes, it will rip apart 3 inch solid steal hulls, and this is just a little water turning into ice. It is a vastly untapped occurrence in the universe.
The major reason for this is that water, or ice as we call it’s solid, is one of only 2 known compounds in the universe that expand when solid instead of contract. This is insanely weird and occurs because of the way the atoms line up because of the hydrogen bonds.
Think of it this way; when water turns to ice, it expands it’s volume by 9.8%, and the reason it does this is the repulsion of like electric charges. It is one of the few known ways to harness the power of the atom at cold temperatures, and it’s just a fluke that it’s as cheap as, well, water, and it doesn’t even have to be clean.
There is a book called “The chemical physics of ice” by a professor of Physics named N.H. Fletcher. You can get it for $6 on Amazon that describes all sorts of things about ice that you may not be aware of, some of it is mind blowing.
You can make an easy engine out of ice by using a 10k psi canister and a massive steel spring; the water will turn to ice and compress the spring by 10%. When it thaws by bringing it indoors, the pressure the spring can produce can power a dynamo and generate a very large amount of electricity while the ice thaws, and this energy simply came from the state change of water; no sun necessary; it just needs to be cold outside.
The amount of energy this simple engine will produce is also next to nothing compared to what you could produce if you could actually contain and harness anything close to the amount of pressure water actually can produce.
Included below is a diagram called a “state change diagram”, common for compounds. It shows the pressures and temperatures water behaves differently at. The blue is the various states of ice. You can see the power you can get out of the state change is virtually limitless, if we could only build something to capture it; water stays solid under 1TPa of pressure passed thousands of degrees C, and maintains it’s expansion.
The most astounding thing about water happens right around 1Gpa of pressure; where ice changes between states 3/4/5, you can see ice starts turning liquid at earlier temperatures, but then, states 6/7/10/11 go off toward some seeming insane value, and nobody knows for sure what happens because we cannot currently test at such high pressures, but we know ice 11 becomes ferro-electric, and scientists assume ice will become a metal around 1.5TPa - 5TPa, yet the stuff still retains a very significant expansion.
Science currently has no idea at what pressure ice will start to contract, and therefore the amount of theoretical power you could get from it. The book I recommended talks a lot about this.
Will you be the one to invent a state-change engine? :)
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