h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

"So what you're saying is that we've no business tinkering with stuff that's er beyond our limited grasp ?"

Well, not in the slightest really, because the area of science under discussion falls well within the realms of the Key Stage 3 curriculum, or what I expect a 14-year-old to know.

"Who said 'nothing'? i'm using water. H and O...what's not to burn?
The device takes a mere 7A from the alternator."

And your alternator derives its energy from the calorific value of the fuel. I think you will find that your new hydrogen-rich fuel has significantly less stored chemical potential and, if pushed beyond its limit, will simply cease operation.

If you suggest that these devices could provide a fuel- and pollution-saving alternative, then I'm all prepared to believe it. If, however, you think they might constitute a viable alternative energy source then you need your head examined.

B

"So what you're saying is that we've no business tinkering with stuff that's er beyond our limited grasp ?"
no.. by all means do experiment, just don't do damage to yourself or to others.

Indeed any 14 year old should by now know a few basic facts.
one of those facts is that you cannot create energy out of nothing. you cannot destroy energy either, just waste it.

So what about the "magic" water electrolysis and burning process? well, as Mu Beta explained, water is pretty stable. you can split it into hydrogen gas and oxygen gas, but that does require quite some energy.
Following the splitting, you can burn the hydrogen and oxygen and that will return quite some energy as well, it will however not return more energy than was used up in the splitting.

Worse even, the energy for the splitting is (usually) electrical energy, and the energy produced in burning is heat. Of course you can use this heat to produce electricity (back to where we started, at 40% efficiency, or motion (in your car) at less than 25% efficiency.

But feel free to experiment. if ever you succeed to produce energy out of nothing then I'll publicly apologise and you can make hilarious fortunes (forget the minor sum of the Nobel prize, there's a lot more to be made).
I also suspect that there are several funny farms filled with people who invented a perpetuum mobile.

http://en.wikipedia.org/wiki/Perpetual_motion and http://en.wikipedia.org/wiki/Stanley_Meyer%27s_water_fuel_cell hold relatively easy discussions on this topic. Do note the frequent use of the term "pseudoscience" there

Yeah, but to be fair that is a pseudopedia.

i'm no scientist

your engine is no where near 100% efficient, makes van go, generates electricity, charges battery etc, wastes power.

by adding O2 ans H2 to the air intake you make the mixture richer and the engine is a little more efficient

engine runs faster, van go's faster, you slow down, you use less fuel,
a little bit of wasted electricity is used to split the water

with development you could probably improve the efficiency again and again but you would reach a point.

the fuel air hhoo mix would be in balance, any more hhoo would make the engine run less efficent or even stall it

what it sounds like you are doing is similar to adding nitrous

but at smaller quantitys and far more controlable

i'm also no engineer

I am an engineer, though admittedly not a chemist. All the others have said basically the same thing, that the energy in the water molecule is in the bonds, and that, given process losses, you can't possibly get more energy out from recombining them than you spent breaking them in the first place.

If that were the case, then a great many very clever people, including those that invented and refined nuclear energy, have been wasting their time. The pursuit of fusion power from electrolysed water would also appear to be a very expensive red herring. I find it hard to believe that all these people have been fooled by simple chemistry that was well understood hundreds of years ago.

So, with that premise in mind, and assuming a ridiculously generous 100% efficiency for a minute, if this device is drawing 7A from a 12V system, the maximum power you could possibly get out is 84W, about 0,1% of what your engine probably produces already, so I can't see how it would make any noticeable difference at all to your fuel consumption, let alone the claimed 36% reduction.

If this effect is real - which I also hard to believe - then something else is going on. Gaseous hydrogen would presumably explode pretty much straight away, which *might* make the fuel mixture burn more efficiently - but I seriously doubt it. The engine is already finely tuned, and I suspect this would just cause it to detonate too early. I have heard of water-injection systems, whereby water vapour slows combustion and therefore allow higher pressures before detonation takes place, but this wouldn't work in this case because the hydrogen/oxygen would have to burn first to generate the water, and that would result in detonation again. However - this is testable, just try injecting the water instead of splitting it first.

Perhaps the extra oxygen is fooling the oxygen sensor? Taff could be correct in that it works like a nitrous setup, where nitrous oxide provides extra oxygen for combustion and the engine management system (if set up to do so) provides extra fuel to compensate.

Whatever, it ain't doing your engine any good.

Well I am a chemist and I agree with most of that.

It was only approximately one hundred years ago (rather than hundreds) that these things were finally understood. Chemistry is only about 150 years old at all as a proper science.

>The pursuit of fusion power from electrolysed water would also appear to be a very expensive red herring.<<

I don't see why this need be so. Electrolysis is a chemical process. Fusion is a nuclear process. The latter is capable of releasing a *lot* more energy than the former consumes - just a few minor technicalities and obstacles remain

Also, hydrogen doesn't really explode on contact with a flame or spark unless it is in a precise (but wide ranging) mixture with oxygen at certain levels. It can burn quite smoothly otherwise.

Having said all that, the whole idea of this thread is preposterous of course.

Replying to part of Post 11 by AlecTrician in an effort to "explain some science".

>Water IS already H and O . That means it has potential energy already...doesn't it?

No it does not.

Hydrogen gas consists of pairs of hydrogen atoms chemically bound together. Similarly, oxygen gas consists of pairs of oxygen atoms chemically bound together. A mixture of hydrogen gas and oxygen gas can be made to release some energy by creating conditions in which the atoms can reorganise themselves to form water (molecules of H20). If they can do that they *will* do so *because* this process releases some energy.

In order to reverse this reaction, that is, in order to split water into hydrogen and oxygen gases, by *any* method - including "by using electrolysis" - you would need to supply at least as much energy as would have been released in the previous paragraph.

So...

>By splitting it using electrolysis you make that already existing energy available to burn.

No. By splitting it using electrolysis you make *some* of the energy you supplied in order to split it available to burn.

> I don't see why this need be so. Electrolysis is a chemical process. Fusion is a nuclear process. The latter is capable of releasing a *lot* more energy than the former consumes - just a few minor technicalities and obstacles remain <

Indeed, but to take the preposterous debate further than it should rightfully go, both systems use water as the base fuel, but with electrolysis (and a lot of imagination), we have a process that would use simple hardware (boilers and turbines) and never runs out of fuel since you get the original fuel back at the end. Its energy yield per gram of fuel is effectively infinite.

No matter how much energy you get from fusion, with all its expensive doughnuts, mega-Tesla magnetic containment systems and seven-figure operating temperatures, you still use *some* fuel therefore its energy yield per gram of fuel is finite and, therefore, infinitely worse than the H20 -> H2 + O -> H2O system .

"Hydrogen gas consists of pairs of hydrogen atoms chemically bound together. Similarly, oxygen gas consists of pairs of oxygen atoms chemically bound together. A mixture of hydrogen gas and oxygen gas can be made to release some energy by creating conditions in which the atoms can reorganise themselves to form water (molecules of H20). If they can do that they *will* do so *because* this process releases some energy."

No, look, this is completely bollocks. If you mix hydrogen and oxygen gas, they will not spontaneously combust, will they?

I didn't really want to have to drag out the bond enthalpy manual to do it, but if there's no other way to convince you:

2H2O -> 2H2 + O2

Bond Formation Enthalpies:

H-O = -463 kJ/mol
H-H = -436 kJ/mol
O=O = -495 kJ/mol

To dissociate fully two water molecules would require the splitting of four H-O bonds, which is an energy intake of = (+463*3) = +1862kJ/mol

To create two hydrogen molecules and one oxygen molecule from the same dissociated atoms would require the formation of two H-H bonds and one O=O bond, which is an energy release of = (-436*2) - 495 = -1367kJ/mol.

It just doesn't add up! You need to take in more energy than can be released by the oxidation reaction. The potential energy referred to above is totally accurate and is referred to by physicists as Chemical Potential and is of the level that I would expect the average 14-year-old to understand.

B

Oh, and you can't burn energy.

B

Umm, if you're going to start using words like 'bollocks' and comparing people to 14 year olds then it might just be advisable to not talk bollocks one's self don't you think?



>No, look, this is completely bollocks. If you mix hydrogen and oxygen gas, they will not spontaneously combust, will they?<

Well, not spontaneously* but provide a small spark and they detonate extremely violently.
With enough energy to say.... power a rocket (e.g. the shuttle) into space ...
Meaning the energy released upon their reaction is rather huge in fact.

A prime example of an exothermic reaction.

Your example with bond enthalpies is in fact just the reverse reaction of the same process.


So without doing any numerical maths

E(2H2O --> 2H2 + O2) = -E(2H2 + O2 ---> 2H2O)


Or to put it another way

The overall process proposed is to do this:


H2O --------------------------> H2O


Where the dotted arrow involves steps involved in electrolysing water and then burning the H2 to make more H2O. The petrol is actually irrelevant - it was burned before and will be burned after.

Where the hell is the potential in that overall reaction**?
Anyone who thinks that has potential needs to start reading science manuals for 14 year olds more carefully.

In fact also the situation is worse since one is presumably starting with liquid water and ending up with gaseous water so in fact, the process does require some energy - unless someone is telling me that turning a liquid into a gas releases energy.


>>It just doesn't add up! You need to take in more energy than can be released by the oxidation reaction. The potential energy referred to above is totally accurate and is referred to by physicists as Chemical Potential and is of the level that I would expect the average 14-year-old to understand.<<

You have it the wrong way around I'm afraid. Water is thermodynamically more stable than a mixture of H2 and O2. And I'm pretty sure I did know this already at 14.


*although actually yes, they will, just very very slowly
** using the word reaction in its loosest possible sense.

***> I don't see why this need be so. Electrolysis is a chemical process. Fusion is a nuclear process. The latter is capable of releasing a *lot* more energy than the former consumes - just a few minor technicalities and obstacles remain <

Indeed, but to take the preposterous debate further than it should rightfully go, both systems use water as the base fuel, but with electrolysis (and a lot of imagination), we have a process that would use simple hardware (boilers and turbines) and never runs out of fuel since you get the original fuel back at the end. Its energy yield per gram of fuel is effectively infinite.

No matter how much energy you get from fusion, with all its expensive doughnuts, mega-Tesla magnetic containment systems and seven-figure operating temperatures, you still use *some* fuel therefore its energy yield per gram of fuel is finite and, therefore, infinitely worse than the H20 -> H2 + O -> H2O system.
***


You've lost me here Dave

The nuclear reaction is essentially

H + H ----> He + ENERGY

That's a vastly higher yielding reaction (in terms of energy release) than *anything* chemical.
I'm not convinced this will every be done by us so that is releases more energy than is used but I don't follow your argument I'm afraid.


You seem to be comparing this to the absurdities of electrolysing water and then burning the hydrogen... That's not what I was talking about...

> Oh, and you can't burn energy.

Thank you, I was quoting the previous line with a correction. One correction too few! Please just omit "to burn" from the end of mine.

> You seem to be comparing this to the absurdities of electrolysing water and then burning the hydrogen... That's not what I was talking about... <

But ... but ... I replied to your reply to my statement "The pursuit of fusion power from electrolysed water would also appear to be a very expensive red herring", which was a direct reference to how inefficient fusion power would be compared to this perpetual motion machine.

And, you have to admit that any reaction that starts with a fuel, produces energy and ends up with the same fuel is *vastly* more fuel efficient than *any* nuclear reaction.

Oh never mind...

Likewise, with a tubeful of big magnets, a lonely electron and some lead, we can manufacture gold and hence remain immune from financial armageddon.

Next week: Time Travel 101.

"And, you have to admit that any reaction that starts with a fuel, produces energy and ends up with the same fuel is *vastly* more fuel efficient than *any* nuclear reaction."

I think you are missing the concept of 'quantity' from that piece of logic.

>And, you have to admit that any reaction that starts with a fuel, produces energy and ends up with the same fuel is *vastly* more fuel efficient than *any* nuclear reaction.

Look, you need to think about what you are posting.

Any reaction that starts with "a fuel" - and we are talking about water here, right? - and ends up with that same "fuel" does not produce any energy. That's it.

Pour yourself a glass of water. Keep watching, that's your fuel efficiency in action.

Parody:

Jumping Off A Cliff, The Next Fuel

If a man jumps off a cliff with a rope round his waist so he drives a dynamo as he falls he can generate some electricty. Awesome! A man and a cliff have potential energy. We should start to exploit this inexhaustable resource immediately.

Clue:

He can only fall *down* the cliff.

<>

but does it improve the efficency of the internal combustion engine????

No, then you use the electricity you generated to power a motor (you could even use the dynamo in reverse!) to pull them back to the top, duh!