Half a croissant, on a plate, with a sign in front of it saying '50c'
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Hydrogen powered Shower

(incorporates regulation to avoid any squeaky bangs)
  [vote for,

When you burn hydrogen, you get water. Okay, water vapor. This is just too much of a serendipitous reaction for my halfbaking brain to avoid any longer. So I give you - the hydrogen powered shower:

The hydrogen powered shower is perhaps two stories high. The ceiling is metal with many small holes, through which water is introduced. For efficiency reasons, the water tank is directly above this.
Hydrogen is burned in the space above the half-bather - both hydrogen gas and air from outside are introduced in stoichiometric proportions, so the oxygen levels inside are not depleted.
This process raises the air temperature at the top of the space. The shower water gains this heat as it falls. Surplus heat warms the metal roof, which acts as a thermal buffer. Full regulation of water temperature is provided by adjusting the rate of hydrogen combustion.
A small pilot-light is required at all times, to prevent explosions.

Extracting air is necessary to counteract the introduction of air for burning. A small pump drives air from the top of the chamber through the shower water - after it leaves the storage tank but before it runs through the shower's ceiling. Passing it through the cold water section increases efficiency by removing as much of the heat from it as possible. (And it also extracts the water-vapor, of course.)

Hydrogen production is another idea entirely. I suggest that it be produced by hydrolysis, using surplus electricity from local wind and solar power. If this is done locally then by one method oxygen is also produced. If that is also stored then it can be used instead of air, with the result that no air extraction from the shower would be required.

Loris, Oct 12 2009


       I like the idea of using the burning of hydrogen for energy with a byproduct of potable water.
FlyingToaster, Oct 13 2009

       Releasing the compressed hydrogen would make the pipe running to the pilot light extremely cold. By extending the length of the release pipe, could it be used for air conditioning or refrigeration as well?   

       "I've seen fire and I've seen rain..."
phoenix, Oct 13 2009

       I'm really wanting some kind of turbulence-vortex system installed in a tall, dimly-lit stainless-steel chamber. Hydrogen would be injected, and the vortex would contain it high above your head while you stand naked and shivering on the floor, gazing upwards. A Van de Graaff generator creates a huge arcing spark which ignites the hydrogen, creating a fireball which simultaneously heats you and showers you. Grab your towel and exit.
pocmloc, Oct 13 2009

       You could make some very good tea this way.
MaxwellBuchanan, Oct 13 2009

       //produced by hydrolysis, using surplus electricity//
Electrolysis, shirley?
coprocephalous, Oct 14 2009

       Hydrogen can be produced by hydrolysis -- just inject super hot steam into a vessel containing charcoal. This results in H2 and CO.   

       But it wouldn't be cost effective to use electricity to provide heat for that hydrolysis -- concentrated solar, on the other hand, might be good for that.   

       Also, using hydrolysis to create hydrogen gas wouldn't produce oxygen.   

       However, if one has "surplus" electricity, then it wouldn't be unreasonable to use it to drive a pressure swing absorption oxygen concentrator, to extract oxygen from the atmosphere.   

       Injecting this pure oxygen into the vessel containing the charcoal could provide the heat necessary to perform hydrolysis (as a substitute for concentrated sunlight), without diluting the hydrogen with nitrogen.
goldbb, Oct 15 2009

       If one does have pure hydrogen, and is going to burn it to heat one's water, then the way that's most obvious (to me) would be to mix the hydrogen with pure oxygen, burn it (producing steam), then use a venturi type device to mix this steam into the water that will be used for bathing.
goldbb, Oct 15 2009

       There's ways and ways to produce hydrogen if you have excess energy - I didn't want to be constrained by any in particular.
And you may well have excess electricity at some points in the day if you've got a large proportion of your needs supplied by renewables like wind and solar. So it occurred to me that it may be worth trying to store some of that energy as hydrogen.

       Electrolysis of ordinary water will give you hydrogen and oxygen, although perhaps rather inefficiently. I was toying with the idea of generating and storing this in water-pressurised vertical columns, next to the shower. These could both be connected to a third water-filled column, topped by a boyancy level regulator, which would supply water for electrolysis, and pressure to drive the gasses to the burner. This is attractive to me for its simplicity, although I must confess I haven't done any calculations as to the volumes required.   

       In reality, burning hydrogen in this way is always going to be a bit of a waste. Maybe as a top-up for the solar water-heating system I suppose.
Loris, Oct 16 2009

       Your system sounds reasonably ingenious, but I dare say that there's not much mention of electrical generation.   

       If your aim is to store electricity from renewable sources in the hydrogen and oxygen (In a sort of open fuel cell setup) and then release it at times when these sources are not generating electricity, one would expect to see a bit more discussion of that.   

       Likewise, if you're burning sufficient hydrogen to meet any off-peak electricity goals, one would expect the amount burned to be more than sufficient for heating the water. Indeed, a heat pump and generator might be necessary to get the excess heat off in order to cut the water vapor back down to a liquid state.
ye_river_xiv, Oct 17 2009

       Here's another idea -- combine hydrogen and oxygen in a fuel cell, and then mix the (hot) water produced with cool water, to produce hot shower water.
goldbb, Oct 18 2009

       I should point out that I'm not proposing that *all* the water for washing be produced from hydrogen. Only a fraction of the water would be produced by the reaction, the rest would be supplied from the mains (or elsewhere) in the usual way.   

       Yes, theoretically one can get more use out of the hydrogen by doing some useful work with it when it is burnt, and use the 'waste' heat for the shower heating. The same is also true of natural gas (ie methane) though, and that's what most people's central heating/hot water is powered by at the moment (in the UK at least). Combined heat and power production sounds lovely in theory, but I think it has some issues in practice which is why it's not widely exploited at the moment.
Loris, Oct 20 2009


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