On 03/05/06, Randall R Schulz wrote:

Carlos,

On Tuesday 02 May 2006 17:04, Carlos E. R. wrote:

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The Tuesday 2006-05-02 at 12:37 +0100, Kevanf1 wrote:

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... The solar energy is then used to split the water. It doesn't take much in the way of electrical power to produce the two gases after all.

No, it takes the same energy as the combination of hydrogen and oxygen will produce later at the motor (or better, at the energy cell). More, in fact, considering losses.

Sadly, electrolysis is a very inefficient way to produce hydrogen gas. And while it's true we've got so very much more solar energy than we need, even after the biosphere gets everything it needs, it still is a wasteful thing to do with a high-quality form of energy such as electricity. If you want to store the energy, which is of course is a practical necessity, since it's rarely needed in proprotion to its availability, you do better to simply pump water uphill! Electromechanical energy conversion (i.e., motors and generators) is a lot more efficient than electrochemical conversion (batteries, fuel cells and electrolysis).

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-- Cheers, Carlos Robinson

Randall Schulz

Sorry guys, I should have made myself a little clearer obviously. I haven't said that solar power would be the 'sole' form of automotive power. I merely embrace it as a supplementary form of power. But those comments about the inefficiency of electrolysis and solar power? It doesn't matter if it is electrolysis produced by the suns rays (photovoltaic) as it is free and is effectively going to waste right now. Solar photovoltaic panels are getting more and more efficient every year. Why not use them? Who knows, in a few years we might well be able to power the wheels directly from solar power. Ok, we'd all have to walk at night ;-))))) Admitedly, the biggest bug bear in a solar powered car is the environmental cost of producing storage cells for night time use. So we have to look at an alternative to that. The day may come when we simply have to because oil will be too expensive for even millionaires to purchase. Of course, if anybody else has any suggestions regarding alternative energy solutions then I'm willing to listen. Perhaps we should take this over to the OT list? I'd very much like to continue the debate as it is very interesting. -- ============================================== I am only human, please forgive me if I make a mistake it is not deliberate. ============================================== PLEASE DON'T drink and drive it's not clever, it's just stupid. Kevan Farmer Linux user #373362 Cheslyn Hay Staffordshire WS6 7HR

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 The Wednesday 2006-05-03 at 09:51 +0100, Kevanf1 wrote:

But those comments about the inefficiency of electrolysis and solar power? It doesn't matter if it is electrolysis produced by the suns rays (photovoltaic) as it is free and is effectively going to waste right now. Solar photovoltaic panels are getting more and more efficient every year. Why not use them? Who knows, in a few years we might well be able to power the wheels directly from solar power.

No matter what you do with the electricity out of the solar panels in a car, be it use it directly, store it by a perfect method, or generate hydrogen, the final energy you get to the weels will always be less than what the panel produced. With perfect conversion, at most you get the same energy. That's all I meant. Just have a look at the cars used for the solar car race in Australia, and notice the big panels they carry. - -- Cheers, Carlos Robinson -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.0 (GNU/Linux) Comment: Made with pgp4pine 1.76 iD8DBQFEWH7DtTMYHG2NR9URAt9yAKCOgyonlvr9zebj64TVRd4CkmLrVQCdFUWQ 5PVc8Rq+piHOrHyUIy6J7bY= =ioZj -----END PGP SIGNATURE-----

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 The Wednesday 2006-05-03 at 22:17 +0200, Orn E. Hansen wrote:

While electrolysis may be a very poor way of producing hydrogen, heat is not. Heat, as an energy form, is in abundance in many places and can be easily used to catalyst the transition of water to hydrogen+oxygen.

The "transition of water to hydrogen+oxygen", as you say, uses a lot of energy, in whatever form you use it, be it electricity, heat, whatever. Remember you can only transform energy, not create it. You will only get from hydrogen engines of any sort at most the same energy you used to generate that hydrogen.

Transportation of hydrogen as a fuel, is by no means a bigger problem, than oil.

Yes, ¡it is! Much bigger. Specifically, "bigger", as in size. I will not go further to explain why because it is OT. - -- Cheers, Carlos Robinson -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.0 (GNU/Linux) Comment: Made with pgp4pine 1.76 iD8DBQFEWUMttTMYHG2NR9URApbmAJ9slYMN5qQUMEEck19N4c8ja/awdQCfa+rm HKQZ5vu21gr4Vqn9lJoI9Zo= =+37Y -----END PGP SIGNATURE-----

On Wednesday 03 May 2006 15:39, David McMillan wrote:

Kevanf1 wrote:

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On 02/05/06, James Knott wrote:

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Kevanf1 wrote:

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There are alternatives but one is branded a conspiracy theorist if you so much as hint at the oil companies perhaps keeping them quiet. There is no reason why we shouldn't have safe engines running on water. There is no need to have a tank of highly flammable hydrogen gas (from the split H20) as it can be split in small quantities and fed into the engine that way.

????

Splitting water into hydrogen and oxygen takes energy. Where does that energy come from? Remember, you can never exceed 100% efficiency and are unlikely to even reach it.

Solar power. Admittedly, solar panels take energy to make them but I don't think they break down fast. So, this would mean that the energy put into making them can be regained from the use of the sun over its lifetime. The solar energy is then used to split the water. It doesn't take much in the way of electrical power to produce the two gases after all.

..have you ever done the energy calculations for this? I doubt there's a solar array on Earth small enough to fit onto a car that can crack water into H2/O2 fast enough to keep up with the demands of an internal combustion engine. Solar is good for a slow, steady *trickle* of electrical power. Not to mention, H2 as a gas is compressible -- water is *not.* And H2, even if you liquify it, is a huge headache for storage, handling, and has literally the worst mass/volume ratio going -- ask any rocket scientist. The *only* reason that it's used in rocket engines is that it gives just about the best ISP possible for current technology in an engine that has enough thrust to get from sea level to orbit (ion engines and their kin have much higher ISPs, but have thrust levels measured in ounces). There's a vigorous minority among rocket scientists who believe that LOX/Kerosene comes close enough to matching LOX/H2, once you consider the mass savings in the huge cryogenic tankage that H2 requires, that if you're going for overall efficiency rather than max performance, LOX/Kerosene probably makes a better choice. To match the total energy of a tank of petrol, you have to have a *much larger* volume of H2 -- the fuel/air ratio is backwards. An ICE burning petrol uses a small amount of fuel combined with a large amount of air. An ICE burning H2 would have to use *twice* as much H2 as air, even if the air was pure oxygen -- with open air being largely N2, it's even worse (note to chemists: I'm leaving aside molar numbers vs volume for the sake of simplicity). You can beat this to a certain extent by using compression, but H2 doesn't compress well, being the lightest element (hence the headaches for rocket scientists). And sufficient compressions produce explosion (from pressure, not falmmability) and/or cryogenic hazards. This is all why most of the leading work in H2-powered automobiles has been concentrating on using H2 "sponges" or fuel-cell equivalents, rather than gaseous H2. If carrying a tank of water and electrolyzing it on-the-fly were *that* easy, we'd be doing it already. And if the automotice companies weren't, then the DIYers who build their own electric cars would be.

Hmmmmmm........Ya know, when I was a little kid, (long long time ago) they had these little toy wind-up cars with a big spring in them. Maybe we should revisit that. :-) Bob S.