[WBL 1952]

http://www.futurepundit.com/archives/000129.html

"Negre explains that, in the tanks, the air is both cooled to minus 100 degrees Centigrade and compressed to 4,500 pounds per square inch. Then it’s injected into a small chamber between the tanks and pistons, where it’s heated up by ambient outside air that forces it to expand into a larger chamber situated between the small chamber and the pistons. That heat exchange between the two chambers, he continues, creates the propulsion that drives the up-and-down strokes of the engine’s four pistons."

OH DRAT.

Those pesky details, like keeping the air at minus 100 degree centigrade while it is parked in the hot sun, just keep getting in the way.................. Wonder how much energy would be used by a portable air conditioner hammering away on a tank of air 24/7 trying to keep it from getting above minus 100 degress centigrade and EXPLODING!!!!!!!!!!!!

[drlevy88]

Those pesky details, like keeping the air at minus 100 degree centigrade while it is parked in the hot sun

If kept in a vacuum insulated tank (big Thermos bottle), it could last a fairly long time. As the compressed (even liquified at that temp?) air heated slowly it would have to be bled off.

[etlib]

Those pesky details, like keeping the air at minus 100 degree centigrade while it is parked in the hot sun, just keep getting in the way.................. Wonder how much energy would be used by a portable air conditioner hammering away on a tank of air 24/7 trying to keep it from getting above minus 100 degrees centigrade and EXPLODING!!!!!!!!!!!!

And where does the energy to get the air down to -100 degrees in the first place come from? I guarantee that compressed air at -100 degrees costs more than $2 per fill-up.

[foghornleghorn]

Something doesn't add up here. How do you go from 120psi to 4500 psi without using energy? And how do you extract the energy from the gas to lower its temperature to -100?

Admittedly, I haven't studied my Thermodynamics in years, but a little voice keeps telling me something doesn't fit.

[Minutemen]

4500 p.s.i. I wouldn't want to be within a half mile of that tank if it splits a seam!

[Erasmus]

The trick is in the insulation. You keep the gas at liquid temperature at or near atmospheric pressure by allowing a small amount of it to evaporate per unit time. How small an amount depends on the quality of your insulation.

Of course, his $2 estimate for charging the tank is entirely bogus. I suspect his 124 miles is too.

[Richard Kimball]

Hi, this is a reply to your private message: and the fact that those firefighter tanks are under such pressure (2200 to 4500) means they have to be inspected at least every three years and replaced if they fail and mind you those tanks endure nowhere near the use these would. we are talking about everyday use, wear and tear, accidents, and the need for safely refilling by your average joe maybe as often as every day.

Luxfer manufactures all the cylinders my academy uses. They have a five year hydro test. I've been in fires that melted my visor, which happens around 600 degrees, with no damage to the SCBA cylinder. Most people no longer have any idea of what goes on in their cars, so maintenance is done by personnel with special training. There would have to be stations set up with quick connects and an interlock mechanism to keep the air from being discharged unless the connection was made properly, but this is all standard, off the shelf technology.

I can't speak to what the actual costs of operating such a vehicle would be, but I don't find the air compression technology to be any more risky than air bags or gasoline tanks.