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RP Device: Water creator

  1. May 11, 2014 #1
    So we are playing a Serenity game, and after the adventure our DM rewards us with a highly rare and expensive water generator! He explains that it works by taking oxygen and hydrogen from the air and combing them to form water. And now we will have this in our ship.

    I stepped away from the table holding my head and saying "must not do science". But on the way home I wanted to find a way to fix this. At first I was thinking "wormhole to the elemental plane of water". But that is a bit unsatisfying and doesn't really sound like the Firefly universe.

    Is there a sensible way for this to work? How much energy would it take for this box to take carbon or some other reasonably available element and turn it into hydrogen? Presumably it would have a little box for the waste neutrons to go until you dumped them out of the ship.

  2. jcsd
  3. May 11, 2014 #2
    " At first I was thinking "wormhole to the elemental plane of water"."
    "How much energy would it take for this box to take carbon or some other reasonably available element and turn it into hydrogen?"

    If they could do such things, why would they transport things from one planet to another, even when they have FTL?
    I can only imagine, that it traps every little amount of water from air, so it can help you survive in a dry terrain.
  4. May 11, 2014 #3
    In the series there is a big technology imbalance with planet Londinium keeping all the high tech stuff out of the hands of the other planets. So you have space ships, but not TV or iPhones.

    Also, this series does not have FTL - everything happens in one big solar system. (I like that idea.)
  5. May 11, 2014 #4


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    The most sensible process would be what GTOM said - extracting water vapour and condensing it. But I've no idea how much water you'd be able to extract that way from the volume held by a single spaceship. It's also going to deplete moisture from air and eventually shut down, unless you manage to use waste water(i.e., urine etc.) to remoisturise air. But then why not just purify it directly without the middle man?

    Then maybe gathering methane(to split into component atoms) and molecular hydrogen from air, but there's so little of either that I can't see this being able to net you a lot of water. There's like 0.002 percent of both taken together in a typical volume of air.
    Same problems with depletion.

    Then, I'm thinking maybe some sort of reverse CNO fusion process? You'd supply energy to split atoms rather than fusing them to extract it. All the components are in abundance in air, and to my barely-educated mind it could work in principle, but I've no clue what technical hurdles you'd have to overcome. It'd sure require A LOT of energy.
  6. May 11, 2014 #5


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    Taking methane and trying to transmute the component atoms into hydrogen is going about this the wrong way: If you simply burn the methane in an oxygen atmosphere, you automatically get water and CO2. The CO2 can be absorbed and turned back into carbon and oxygen, altho at an energy price.
  7. May 11, 2014 #6
    What makes this descend into hopeless stupidity is that the device is expected to be highly useful on a spaceship. So any water you get from this is really just coming from your life support system. That is why I proposed some kind of fission reaction to turn unwanted atoms (carbon) into something you'd need in space.

    Back to the elemental plane of water: If there was a hole one square millimeter in area, and the water pressure behind it was about the same as the bottom of the Mariana Trench (1,086 bars = 15,750 psi) How much water would come out per minute? That answers GTOM's question btw.

    If it is 15,750 psi, does that mean that 15,750 pounds of water would come out of the hole in some fixed period of time? I'm not clear on how to get a time factor out of this.
  8. May 11, 2014 #7


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    I'm a little confused by the description of the water generator in the OP: Taking hydrogen and oxygen from the air and turning them into liquid water. Well, I own such a device, as do most people: it's called an "air conditioner". What's the problem? I don't see why element transmutation is implied from that description.
  9. May 11, 2014 #8
    Water vapor in the air is not "hydrogen and oxygen" as such things are normally described, it is simply water vapor. As described, this device would only work in an atmosphere full of H2, which means that your space ship will explode if anyone strikes a match.

    The machine is expected to be something rare and exotic in a world where space travel is common. Any ship would need to regulate water vapor. So this device must create water from some non-obvious source that would be practical on a spaceship.
  10. May 12, 2014 #9


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    Lol. Of course!
  11. May 12, 2014 #10
    So this device must create water from some non-obvious source that would be practical on a spaceship.

    If no FTL, then wormhole teleportation from an ocean isnt plausible...
    If it transmutes some other material, that will be depleted, why dont they bring more water simply?
    If turns energy into matter... so the reactor turns matter into energy, then reverse? They could bring more oxigen, and burn hydrogen fuel with it...

    I can rather imagine that in a fantasy setting, bind a water spirit. :P
  12. May 13, 2014 #11
    What about staying with idea that's just air conditioning, while the whole team got ripped off?

    I understand that pseudo scientific explanation like "it converts dark matter in to water" is not what you are looking for?
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