about hydrogen cars??

[Insidious]

Ok, that was fun

 

[OIKOS]

Bush said he'll help invest the technology.... is it true??

i thought he owns some oil companies...

 

[rgwalt]

Originally posted by: etech

Originally posted by: rgwalt

Originally posted by: NeoPTLD

Originally posted by: rgwalt
These fine people are correct, but a couple of clarifcations... Electrolysis is only about 50% efficient, meaning it takes twice as much energy to liberate a given amount of hydrogen than would be produced when that hydrogen is re-combined with oxygen to form water. That being said, you also have a reduction in efficiency in combustion. So, water will never be used as a on-vehicle fuel source until we have fusion reactors under our hoods.

Secondly, liquid hydrogen is only "cold" when at atmospheric pressure. You can store hydrogen as a liquid at room temperature, but it has to be at very high pressure. This poses a very dangerous problem, too.

Ryan

No you can not store liquid hydrogen at room temperature regardless of pressure. There is a factor called "critical temperature" and once you're above that temperature, you can not keep it liquefied regardless of pressure applied. The critical temperature of liquid H2 is way below room temp.

OK, you are right. The CT for hydrogen is around -400 F. However, you can store it as a supercritical fluid at room temperature and high enough pressure. At these pressures you can't classify the hydrogen as a liquid or a gas.

Ryan

Any idea what pressure is necessary?

One trivia fact. Liquid hydrogen is so cold that it can condense oxygen from air. If liquid oxygen drips onto asphalt it can start a fire.

No, I don't have a phase diagram for hydrogen handy, unfortunately.

Ryan

 

[MikeMike]

i got a nice 3-4 page rport, with citations MLA format you can use, just pm me for it and i will paste it into the pm


It was written by me and i give you permission to use whatever amount of it you want



MIke

 

[spyordie007]

We have quite a bit of information on using Hydrogen for transportation, both with fuel cells and in an internal combustion engine. I would recommend posting some of your questions on our forum (listed below), I'm sure some of the guys would love to answer your questions.
plug
www.ahanw.org
Our online forum (the place to ask questions)
/plug

-Spy

 

[Armitage]

Originally posted by: Insidious

Originally posted by: OIKOS
what are some disadvantages about fuel cells???

expense, non-optimized technology, no infrastructure to get the fuel to the vehicles, and the fact
that somewhere along the line people are going to realize that despite cleaning up our vehicles,
we will make one big friggin mess with the H2 production. (last I heard, electrical power plants
are also of the devil....)

and last, but not least..... powerful people who have interest in the fossil fuel industry :disgust:

Actually, the fossil fuel industry loves hydrogen ... because unless we go to nukes or make some huge breakthroughs in solar power, going to a significant "hydrogen economy" will increase consumption of fossil fuels.

The primary source of hydrogen today is reforming natural gas @ about 50% to 70% efficiency. So to get an amount of hydrogen that can produce 1 unit of energy, you have to put about 1.4 to 2 units of energy into the process. So, the raw material going in is a fossil fuel, and the energy needed to extract the hydrogen is also a fossil fuel.

On the electrolysis side, the efficiencies are pretty low, and again, where does the energy come from ... most likely fossil fuels.

The fossil fuel industry is falling all over themselves to support hydrogen ... would be the biggest thing for them since the internal combustion engine, and they get to look "environment friendly" at the same time.

There was a thread about this last week also.