[Chicagoan]

Forgive me if this is totally stupid; I am not an engineer. But suppose we could set up a windmill that uses mechanical energy to compress air, like a tire pump and use that to charge up an air car. I am wondering if it would be possible. How much air pressure are we talking about?

[Devil]

What the hell is all this mania about using air? Have you never blown up a bicycle tyre with a hand pump? What happens? The bloody pump gets hot, that's what! Have you ever thought why and the consequences? The why is simple. You need energy to compress the air. Where does that energy go? It is dissipated in the form of heat, which is then lost. Even if you buy a small DIY compressor for paint spraying, there are fins round the cylinder to prevent it from overheating. Now all the heat that is generated is lost, so is the energy you used. This is called adiabatic compression. So the amount of energy you have when you use the compressed air is very small compared with the amount of energy you put in. IOW, it is a bloody inefficient method, compared with even winding up a clockwork spring or a rubber band to drive your car.

Forget compressed air cars: the holistic efficiency is so poor that they are as much a waste of time as reading your stupid suggestion.

[Jack]

$this->bbcode_second_pass_quote('Devil', 'W')hat the hell is all this mania about using air?

[Laurasia]

Let's be nice to each other, shall we? A suggestion was posted in polite, even humble terms, and should be answered or commented on, in the same tone. We are presumably all here because we're worried, and we're looking for answers and solutions.

May we all have a great day!

L.

[dontworryaboutpeakoil]

Yes I agree we should be nice to each other. Not all of us are engineers here and I don't think there is such a thing as a stupid idea. We are a little short of ideas here on how to solve Peak Oil.

And for your information, the AIR CAR is working techology TODAY! I don't know how it works but it's a brilliant idea. Using compressed air to drive a motor looks like the best solution to me. As long as it works, I don't give a damn how stupid it sounds.

What I don't understand is why Ford, GM, Honda, etc are exploring this new novel technology. The oil will not last forever. We should get started TODAY on commercializing this.

[Chicagoan]

You guys don't have to be rude I am not an engineer. And I did not say that air cars are the solution to all of our problems. My post was more of a question. I am majoring in history. When I can contribute something from my field, I do. But now I am asking a question, so can you please answer it? Thank you!

I am trying plan my future life. A bike is good for transporting yourself, but what if you have to haul something? My question was how much air pressure would an air car require. Windmills can apply quite a bit of pressure but is it enough? What is their range?

[backstop]

Chicagoan - I'm not an engineer either, but as far as I understand the issue of comparative energy efficiency, your windmill will send your vehicle more than twice as far if you use it to generate power stored in a battery, and use that power to run an electric motor driving the wheels.

However you'd still have a relatively poor "ton-miles" range per $1,000 invested the mill, generator, and electronics, etc compared even with very basic wood gasification for transport.

If interested see the FEMA website for its plans for a locally-made gasifier large enough to drive a small tractor. This option is both cheap to construct and is not reliant on intermittent wind supply; against these advantages it does of course require a sustainable source of woody biomass (or preferably charcoal) to provide reliable road transport.

regards,

Backstop

[Devil]

I never said you could not drive a car on compressed air. I said it was so damned inefficient that it was not worth considering and, physically, could not be made efficient because of the adiabatic compression. As a guestimate, for every joule used to drive the wheels, you would need 50 to 100 joules on the input side. IOW, it is 15 to 30 times more efficient to use an ICE and this is the name of the game. We need fewer joules on the input side to obtain the same number on the output, not the other way round.

I make no apologies for my tone. This forum is spoilt by harebrained ideas emanating from, hopefully, well-intentioned persons who haven't got a clue about what they are talking. Maybe it should be split between two forums, one for these ideas plus the kookies and fruitcakes and the other for qualified scientists, technologists and engineers only (i.e., those who believe in the laws of physics), with ruthless moderation to transfer anything inappropriate to the other one.

[Chicagoan]

$this->bbcode_second_pass_quote('backstop', '
')However you'd still have a relatively poor "ton-miles" range per $1,000 invested the mill, generator, and electronics, etc compared even with very basic wood gasification for transport.

If interested see the FEMA website for its plans for a locally-made gasifier large enough to drive a small tractor. This option is both cheap to construct and is not reliant on intermittent wind supply; against these advantages it does of course require a sustainable source of woody biomass (or preferably charcoal) to provide reliable road transport.

regards,

Backstop

[Chicagoan]

If something won't work, all you guys have to do is explain why. And if you don't want to waste your time on us idiots, don't open the thread. We are all in the same boat, so we might as well get along.