Why no one makes freeze-powered generator yet?

>>16723309 (OP)
>43000 psi
So about 3*10^8 N/m^2. Back-of-the-envelope now says that if your ice is pushing on a 1m^2 surface and pushes it 1m that’s 3*10^8 J = 300 megajoules.
>1L of gasoline contains 30 megajoules
so one cycle of this giant ice contraption is no better than just burning 10L of gasoline. Still it could be useful if you could get it to cycle naturally (maybe once a day in a cold enough country?) and it didn’t need a lot of maintenance.

You could theoretically generate power this way. But why would you?
You could only use it while the water is freezing (or melting if it's in a sufficiently sealed chamber) and it would stop the moment the phase transition is complete.
So you'd only get a few days of use out of it per year.

>>16723318
What if you used a heat source to melt the ice and start the process again?

>>16723320
Then you might as well just use the heat source for power. It would be more efficient.

>>16723317
>1m
what is the size difference between water at its densest and ice? how much water would you need to generate 1m of expansion in one direction?

>>16723326
internet says about 8% difference, so we’re talking about 125m^3 = 33000 gallons of water to get that "new" 1m^3. picrel could hold it and take the pressure, but just looking at it, it's gonna take a long time to freeze and thaw. I'm drawing a blank here at how were gonna turn a profit on this thing.

>>16723326
water seems to be 9% denser than ice

What if you used it in a desert where the temperature could drop below freezing at night?

>>16723309 (OP)
We have. And they're closer than you think.

>>16723456
sounds like just the thing for a nice warm pulsating onahole

>>16723317
I feel like the thaw time/energy make this such a slow contraption as to mitigate whatever benefits it may have had over gasoline

>>16723317
>pushing on a 1m^2 surface
>and pushes it 1m
That's like 10m^3 of ice isn't it? And force will probably drop ~linearly between 0 and 1m of displacement. So I'd assume you'd get 150 megajoules or so. Or I guess you don't have to let it expand completely, could use 20m^3 and get 230 ish for 1m of displacement.
You'd need upwards of 30 tons of ice to store as much power as 9 kg of gasoline. Ice is cheap but the giant pressure vessel won't be.
>>16723349
Let's be generous and assume a sky temperature of -20C and perfect emissivity. For one square meter:
5.67*10^(-8)*(273^4-253^4)= 83 W. At best. Fairly sure that by preventing it from expanding you'll drop the freezing point but idk by how much. If it drops to -5c then you're getting 60W.
Can get roughly double that with a regular photovoltaic panel (notably not at night...).
Could blow cold air through instead but in that case no way you'll get a nice mechanically simple machine.
Thick walls means poor heat transfer, thin walls means your gizmo will burst open. Might work with a bunch of thin vertical copper tubes filled with ice, but your welds at the bottom better be good.
Idk man, napkin says no.

>>16723732
>5.67*10^(-8)*(273^4-253^4)= 83 W
Should probably expand on that. That's the heat you need to shed to freeze it. It takes 300 megajoule to melt a single cubic meter of ice, but you'd need 10+ cubic meter to get 150 megajoules by expansion. Seems like a really shitty heat engine.

When you plot a thermodynamic cycle on a TS graph, the area enclosed gives the reversible work. OP's cycle (yellow) has such a small area compared with the Rankine cycle (purple) so the heat engine has to be big. Antarctica has those pressures and temperatures.

>>16723855
>yellow
?

>>16723858
It should read red instead.