Re: Quick calculations
> it would still have roughly the same amount of energy available for the same chemical reaction.
If it were atomic or molecular hydrogen, that would be true. But it isn't - it's H+ ions. And they don't burn.
> once you get the hydrogen out with the electrolytic cell it will burn just fine
Yes, but to get the hydrogen out with the cell requires more energy than you will get back from the hydrogen. The cell is a net energy loss.
> I think you're confused
I'm not confused in the slightest. I am merely annoyed that people keep promoting energy sinks as energy sources. This cell idea is an energy sink.
> and another process as the only heat and pressure that these kids need
Yeah, as you seem to have entirely missed the point, the process I was talking about by which you can extract energy from hydrogen ions is nuclear fusion. It worries me that I have to spell it out in such detail.
> I didn't say it was efficient and I agree on that point
You seem to have missed the boat on *how* inefficient it is; the power used to drive the cell would be better put into a simple battery. That would leave much more energy available as electricity. Pumping it through this hydrogen cycle leaves less energy available for use than if it had not been used in the first place.
This isn't a case of "it could be better", it's a case of "it would be better not to bother".
> I will say the amount of energy used to break those bonds is about 123 MJ per kilogram
You're assuming 100% efficiency. This does not occur at all, but in a heat engine - which is in use in this cycle - the absolute maximum efficiency that can be achieved is 1-(Tc/Th), where Tc and Th are measured in kelvin. Given a Th somewhere in the region of 500K - which is probably being a bit generous - and a Tc of around 300K, the absolute maximum efficiency that can be achieved with absolutely ideal, perfect components is 40%. This is being generous, as in practice it's going to be half that. Compare that to >80% efficiency just storing the energy in a battery, and you have a better picture of why this is such a waste of time.
> The fact that inefficiency exists in the system means it isn't perpetual motion or "free energy"
Precisely so. It is, in fact, a *waste* of energy. Significantly more energy would be available if the whole electrolysis thing was just abandoned.
> only 20% or less will come out of the generator.
THat's 20% or so *of the energy put into the generator*. You've already lost ~50% of your energy in the electrolysis cell, leaving around 10% of the inoput energy coming out of the generator. In other words, you have to pump into the system 10 times the amount of energy you get out of the back of it. Alternatively, you could just not bother with the system and use the energy you're feeding it more effectively elsewhere.
> in total the process efficiency might be as high as 10% on a good day.
So why use it? You've got 100% available from the energy source, or 10% of that energy after you've wasted 90% in an electrolysis / heat engine combination. I really fail to see why you are championing a setup that just wastes energy.
> it's an experiment, an interesting way of learning for these kids
And as a bit of fun, that's just fine. As a source of energy, it is very far from it.