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Hydrogen on demand systems

  1. Sep 19, 2012 #1
    I was wondering if someone could explain how the laws of thermodynamics apply to these so called hydrogen on demand systems and or how these laws govern the operations of these systems. Physics is my next college course but, I am not asking this for any assignments I have, just a personal interest.
  2. jcsd
  3. Sep 20, 2012 #2


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    Are you thinking of products designed to be fitted to a car to improve mpg or allow your car to "run on water"?

    They use electricity from the car battery to turn water into hydrogen (and oxygen) which is then burned in the engine where it turns back into "water".

    The law of conservation of energy says there should be no net gain. In practice the power gain in the engine will be more than offset buy losses (eg in the alternator that recharges the battery, or in the electrolysis of the water).

    However some people claim that the hydrogen doesn't just turn back into water in the engine. They claim it allows the fuel to burn more efficiently.

    The fact that car manufacturers don't fit such systems as standard is proof they don't work.

    It's also interesting to compare the rate of hydrogen production from these devices with the rate at which a carb sucks in air.
  4. Sep 25, 2012 #3
    yeah, that was something else I didn't get. The rate a carb sucks in air. I have a 600 holley on my vehicle. It sucks in 600 cubic feet of air a minute. That's a lot of air, (I hope that's right, cubic feet and not inches) Either way, I have never seen an on demand system that could keep up with that. I did look at the CNG systems ford has. They use a specially designed tank that holds CNG at 3600 psi. In order to be efficient in running the vehicle, it has to be regulated down to 125 psi going into the engine. It also requires a special fuel rail (modification)attachment. For the good system you can set aside about 12000 dollars too. I would think the same would be true for the hydro gas too wouldn't it? Also in those "on-demand" systems, are they using both pure hydrogen gas and oxygen? Pure oxygen is pretty volatile itself. By their self both of those gases are explosive. If they are right then they should have two separate tanks, one to collect the hydrogen and one for the oxygen? I know pure hydrogen is as volatile as gasoline but, I've heard pure oxygen is worse. Sounds like dangerous stuff if the right precautions are not taken to control, compress and regulate these systems. Could explain all the mis-haps I've seen too...But hey they're trying. Maybe they need to start with re-designing the inefficient engine they are putting these on, that are designed to burn liquid fuel and not gas.
    Last edited: Sep 25, 2012
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