How feasible would super-dense water be as a fuel source for a steam engine?

[BrodyDaMan]

So I discovered the Winans Steam Gun, which had a curved barrel attached to a metal slab that would rotate at 3000+ RPM and propel projectiles fed into the barrel from the top with centrifugal force. Here's a cross-section of the spinner:

The TV show Mythbusters managed to build a version of this gun and it seemed to work pretty well. The biggest problems were that there was no way to ensure that the bullets were going out toward the target rather than the rest of the 360 degrees, and weaknesses of the plumbing and chains. The latter can be solved with better materials, and for the former, my idea is to use a timing disc, which would be a flat aluminium geared plate with holes in it, that would rotate at the right speed between the feeding tube and the spinner tube to feed bullets into the spinner at the right time for it to go out correctly.

However, the other issue is the giant heaters. I like mechanics and software, but I have no idea about chemistry and a few google searches didn't find any results, so I figured some autists here could figure it out. Would denser water, or even super-dense water, produce higher or even equivalent steam pressure to normal water while occupying less space, and if this is the case, would there be a way to use smaller heaters with dense water to create a more portable Winans gun?

 

[Sperg_rancher]

super-dense water,

one thing to note is that water is only "super-dense" while under pressure, and guess what happens once you reach a certain pressure? The water becomes supercritical, and there's no 'liquid' or 'gaseous' phases. When there's no liquid or gaseous phase, then gas expansion doesn't occur, and the energy that's normally stored in the form of pressure to operate any steam powered contraption is only held in temperature now.

in short: I don't think it's feasible without a nasa-scale budget.

 

[Zbk3VmLfujjzjxBd43tL]

one thing to note is that water is only "super-dense" while under pressure, and guess what happens once you reach a certain pressure? The water becomes supercritical, and there's no 'liquid' or 'gaseous' phases. When there's no liquid or gaseous phase, then gas expansion doesn't occur, and the energy that's normally stored in the form of pressure to operate any steam powered contraption is only held in temperature now.

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in short: I don't think it's feasible without a nasa-scale budget.

That is why you use supercritical CO2 instead. Its critical point is WAY less than water in terms of pressure and especially temperature. It's so useful that they actually have built steam turbines with it and they're extremely efficient.

The only problem is that supercritical CO2 fouls up the machinery, which is really shit if you're operating at such high temperature and pressure. There are good alloys for resisting that effect and making it useful, but it seems the alloys are expensive and imperfect so you end up doing more maintenance and replacement than you would with a conventional steam turbine.

 

[StyxHexenHamster1350]

As has been said already. You're not going to make water denser in any way that is useful to a steam engine. And water that is made denser by adding certain toxic salts is only HEAVIER, not more expansive when it becomes steam.

What you want is a Rankine steam engine which operates as a closed cycle similar to the way the steam turbine in a nuclear reactor works.

Now you don't need a bigger steam engine or denser water; you need a larger heat source and a larger thermal radiator.

 

[Fastest Hand In The East]

If I remember correctly in the late 19th- early 20th century navies did experiments on compressing water for the ship boilers and came to the conclusion that it wasn't worth it, so they went all into super-heated steam.

 

[A Cardboard Box]

and a larger thermal radiator.

Depending on the output of the engine, you could use some of that energy for active cooling to reduce the required size of the radiator. Even something simple like condenser coils with a fan blowing through them would improve efficiency significantly.

 

[Londo]

Super dense water is ice, and only feasible in very specific conditions such as extreme pressure or intense gravity -- neither of which exist easily on Earth, or at all. It exists on planets and moons outside of our own but rarely.

It would use more energy in the process than it is able to regain. On top of the energy required to create the conditions possible to create super dense water. Others have pointed out that this has been attempted previously and was found to be basically useless/worthless or with no real gain.

The space you'd be able to save via compression would be outweighed significantly by the materials required to keep super dense water in the right conditions -- and then you have to consider that as the water is used it would reduce the density and defeat the purpose. You'd need to keep a constant pressure, and even hydraulics would struggle to do this safely for something like an engine. Any crack or breach under pressure turns that water in to the equivalent of a lightsaber.

Even if it were possible, compared to our methods of energy generation it would be super inefficient.

I'm not a physicist or chemist, so maybe I'm wrong but from my understanding of the dynamics involved the above is my best guess.

 

[Jewthulhu]

Haven't they been experimenting with denser liquids for nuclear reactors? Or am I misremembering?

 

[Londo]

Haven't they been experimenting with denser liquids for nuclear reactors? Or am I misremembering?

If you're referring to nuclear energy then that would be heavy water which is an isotope (D2O) not a compressed form of H2O.

They experiment with compression for fission but not with water. Water is actually incredibly difficult to densify without being on a planet with extreme gravity and extreme temps compared to Earth.

 

[Jewthulhu]

I know heavy water is different. I just thought I remembered reading somewhere that they were playing with using denser fluids in some part of it.
I thought it was for the steam turbine portion but looking into it the closest I'm finding is using liquid metal for the coolant.

 

[Londo]

I know heavy water is different. I just thought I remembered reading somewhere that they were playing with using denser fluids in some part of it.
I thought it was for the steam turbine portion but looking into it the closest I'm finding is using liquid metal for the coolant.

That makes more sense.

One of the reasons water is used in these processes is that it can be filtered of the harmful elements and then released easily back in to the environment

 

[Thé au lait]

If you're thinking of heavy water, that also needs a higher temperature to turn to vapor than regular water. The heat of vaporization is higher as well, meaning once you get to that higher temperature you still need even more energy to actually vaporize it.

Remember that boiling temperature isn't the temperature required to cause vaporization, it's the temperature that a substance will stop heating at when it needs to absorb more energy to actually vaporize.

 

[Londo]

If you're thinking of heavy water, that also needs a higher temperature to turn to vapor than regular water. The heat of vaporization is higher as well, meaning once you get to that higher temperature you still need even more energy to actually vaporize it.

Remember that boiling temperature isn't the temperature required to cause vaporization, it's the temperature that a substance will stop heating at when it needs to absorb more energy to actually vaporize.

Isn't heavy water used as a moderator rather than a direct source of kinetic and heat energy for the turbine though?

 

[Thé au lait]

Isn't heavy water used as a moderator rather than a direct source of kinetic and heat energy for the turbine though?

My bad, I meant to reply to the OP. In a nuclear reactor yes, it would be used as a moderator because it's less likely to capture a neutron, so the fission reaction is more likely to occur. The steam for the turbine would be regular water, since it's easier to vaporize.

I assumed OP was thinking to use it for the steam that would power the weapon, which would be needlessly expensive and not particularly useful

 

[Londo]

My bad, I meant to reply to the OP. In a nuclear reactor yes, it would be used as a moderator because it's less likely to capture a neutron, so the fission reaction is more likely to occur. The steam for the turbine would be regular water, since it's easier to vaporize.

I assumed OP was thinking to use it for the steam that would power the weapon, which would be needlessly expensive and not particularly useful

I don't think it would be possible. Super dense water is literally hyper compacted ice. Unless they find a way to generate this efficiently or harvest the deepest polar sea ice, or change physics on the planet there wouldn't be any benefit.

 

[Otis Mallebrok]

I know heavy water is different. I just thought I remembered reading somewhere that they were playing with using denser fluids in some part of it.

Supercritical fluid. Either water or CO2. But it is not actually denser.

 

[Thé au lait]

I don't think it would be possible. Super dense water is literally hyper compacted ice. Unless they find a way to generate this efficiently or harvest the deepest polar sea ice, or change physics on the planet there wouldn't be any benefit.

That's why I assumed he was thinking of heavy water instead lol

 

[Anti Snigger]

Isn't water incompressible or am I schizoposting

 

[anklyscr]

Super dense water is ice, and only feasible in very specific conditions such as extreme pressure or intense gravity -- neither of which exist easily on Earth, or at all. It exists on planets and moons outside of our own but rarely.

I'm not a physicist or chemist, so maybe I'm wrong but from my understanding of the dynamics involved the above is my best guess.

ice is not super dense water , in fact its so not dense that you can put blocks of ice into boiling water and have it float on the surface.

 

[Londo]

ice is not super dense water , in fact its so not dense that you can put blocks of ice into boiling water and have it float on the surface.

Not all ice is super dense water, however all super sense water is ice.

Also I know you're likely meming and 10/10 wholesome.