Geek Noise
Rants, rambles, news and notes by Peter Provost
24

Water for Gas and the First Law of Thermodynamics

Wednesday, 24 September 2008 10:55 by Peter Provost

snake-oil I’m always amazed at the things people will believe. Today I got trackback spam from a “water for gas” site on my miles per gallon post. (The trackback has since been deleted.)

I hadn’t run across this particular “technology” yet, so I dug into it a bit. It turns out there are dozens of sites out there claiming you can add a water-based fuel system to your car to significantly improve your gas mileage.

The gist of what they’re claiming is simple:

  1. You use energy from your car’s electrical system to electrolyze water into Hydrogen and Oxygen.
  2. You then run the gaseous hydrogen and oxygen back into your intake manifold where it burns in your engine’s combustion chamber, resulting in more power with less gasoline used.

Sound oh so simple. Except that this is yet another instance of someone peddling a perpetual motion machine.

Here’s the problem: The first law of thermodynamics states:

The increase in the internal energy of a system is equal to the amount of energy added by heating the system, minus the amount lost as a result of the work done by the system on its surroundings

In layman’s terms, this means you can’t get something for nothing. Applying that to the water for gas system, it basically means you will use more energy electrolyzing the water into hydrogen and oxygen than you will get combining them back together when you burn them in your engine.

In other words, if you took the gasoline completely out of the equation, you would eventually have your battery die because the engine wouldn’t make as much energy as it produced. (See this breakdown of the math if you want more info.)

What is more interesting than the bunk science displayed here is the willingness of people to be duped by this and respond with things like “but my friend has one and it works great”. Here we have some guy in middle-America (with little or no scientific or engineering experience and certainly without any of the proper equipment necessary to actually test this) telling you that the last 200 years of science and engineering are false and that perpetual motion (or snake oil) are real. The fact is, most of these scams are actually MLMs and Pyramid Schemes, do I guess we shouldn’t be surprised at the misleading information.

Remember people: If something seems too good to be true, it almost always is! The ultimate test for this in on, however. Bruce Simpson has offered up a million dollars to the first person who can prove it works. Read more over at the One Million Dollar HHO Challenge site. (He’s got a bunch of other great links to the real science involved here in case you want more info.)

So thanks to the trackback guy for letting me learn a bit about this new form of Snake Oil. Hopefully this will help a few more people save their money for things that actually will save money on fuel, like cars that get better mileage.

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Comments

September 24. 2008 22:04

Ryan Baker

Peter, I'm just as convinced as you are that these systems are snake oil, but you're exaggerating how closed the case is. There are plausible explanations for a system like that increasing mileage, though I would never believe them without a truly reputable test result.

For example, if the conversion from H2O to H2 and O2 was extremely efficient (I've yet to hear of one), and the addition of H2 to the gasoline didn't just add energy, but also increased the burn efficiency of the gasoline itself (which is normally only 30%) or so, then yes, there could be a mileage increase without having created a perpetual motion machine.

To say it another way, the only way creating a fuel out of energy and combining it with a second fuel source will have a net energy benefit is if it helps you reclaim some of the waste from inefficient burning of the second fuel source.

I'll even go so far as to say that I wouldn't be completely surprised to hear that there is some engine out there was designed so poorly, or is so poorly tuned for burning gasoline that the addition of hydrogen is a net benefit even after electrolysis costs.

But the chances that more than 0.1% of all engines out there can benefit is very slim, and the chance that your average modern car would benefit I'd rate as essentially zero.

Ryan Baker

September 25. 2008 16:04

Peter Provost

Sure, IF the addition of HHO to the cylinder improves the efficiency of the gasoline burn, then the total net win in terms of energy will be that improvement minus the cost of running the electrolyzing system (which is always a net loss).

And as a scientific skeptic, without any evidence that this is true (not some old fart in Kansas, but real lab evidence that adding HHO improves engine efficiency), then it isn't real to me.

Peter Provost

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