Hydrogen Fuel Cells - Info needed

[Phantasm]

Hi guys,

I'm working on a project (nothing really groundbreaking or exciting but I'll tell you about it if youre curious) that will produce hydrogen as part of the process. I'm going to need to re-combine the hydrogen back into water where I got it from and initially I thought I could just burn it but then I realized that a hydrogen fuel cell does exactly this and yet harvests electricity from the process.

So I'm wondering, how difficult is it to make a hydrogen fuel cell that combines hydrogen with oxygen and harvests electricity? Any DIY guides?

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EDIT:

So far, I've got this link: http://en.wikipedia.org/wiki/Molten_carbonate_fuel_cell

At first glace, it looks kind of counter intuitive I mean, you need a molten fluid - which would presumably cost way more energy to produce than you'd ever get out of recombining hydrogen with O2 however, I realize I'm sure you could devise some way of focusing sunlight to achieve the same result.

Any other approaches?

Is there something that functions over a longer period of time as a draw back? I dont mind if the process is slow...

[Farrah Day]

Have you really thought this through before you go to all the trouble and expense, as a hydrogen fuel cell is a lot more difficult to make than an electrolyser.

Obviously hydrogen fuel cells generate current flow so are only of benefit to electrical motors.  If you have a tanked hydrogen source available then all well and good. However, if you intend to electrolyse water to get hydrogen then there is nothing to gain - all you get back is the current you used in the first place (well less if you considered the efficiency losses).

The only real bonus of a hydrogen fuel cell is that electric motors are themselves far more efficient than ICEs.  But you still have to make the H2 in the first place!

[Phantasm]

Of course youre completely correct,

I'm trying to concentrate a solution by getting water out of the system by electrolyzing without boiling or evaporating (which i suppose i could do instead)

I was just thinking that I could get pure water while concentrating the fluid that the water came from and still recover some energy invested in concentrating the fluid... youre right too, there would be energy lost, but recovering some would be still helpful

In the end, i think the overall cost and complexity of a fuel cell will make the project much more complicated than it needs to be... its still an interesting topic for the forums though ^_^

[Phantasm]

WOW ok so I've been doing some digging and this technology is FASCINATING

Aside from the fact that its quite clear I'm not going to need this technology for my current project I'm still quite interested...

I've been watching some lectures on fuel cells and learning a lot about how they work and similar technology

Did you know theyve had fuel cell type technology since the mid 1800's

When powerplants were newer, there was a lot of counter consideration put into having fuel cells based on IRON as it was more technologically efficient to produce iron than power from power plants (~5% efficient at the time). They wanted to deliver iron plates to consumers to use in their fuel cells - the iron plates would oxadize and electricity would be captured from the oxidation of iron to iron oxide.

Actually, any metal that oxadizes, you can make a fuel cell out of but what we want is readily renewable fuel cells - iron oxide being a little trickier to re-convert to iron than what the average user would like..

Essentially the heart of a fuel cells is the PEM (Proton exchange membrane) which is primarily a Zirconium oxide latice as thin as you can get it and with a bit of supporting structure

You can also use more fancy polymers... but either way, this is the tricky bit when making home-made fuel cells that use a PEM. I'm still digesting these lectures so hopefully theyre'll be some talk of simpler/more common PEM's or lower tech fuel cells that are still renewable

I'll keep you posted