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02-19-2010, 05:43 PM | #2 (permalink) |
Misanthropologist
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We've discussed this at length here before.
Their business model is very shady, and the efficiency is just not there. Too much of the power inputted is wasted as heat. Costs nothing? Of course it cost money. Money in electricity to compress the air into the tanks. An air tank is just like a battery, but it's energy per weight and volume is meager and they're more dramatically affected by temperature. Complete bull****.
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02-19-2010, 08:36 PM | #3 (permalink) |
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Compressed air is capable of much higher power flow than batteries and much cheaper than large capacitors, which is especially useful for braking. As such, it is really useful to complement batteries rather than replace them.
Also note that it might be possible to build a mild hybrid with compressed air for much cheaper than by adding batteries. Air start system - Wikipedia, the free encyclopedia
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02-21-2010, 10:49 AM | #4 (permalink) |
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Actually it is possible to compress air using an "open" water/hydraulic system that is nearly 100% efficient, no different than using the ocean's pressure to compress air. Also the water/oil can be cycled and cooled taking advantage of environmental temperature.
Also temperature provides a unique opportunity to compress in cold hi pressure environments and use in lower pressure warmer environments. I think compressed air cars could have a usage much the same as a short distance AC powered EV but likely at less cost. Since we consider things like hydrogen, which are much more infrastructure intensive and also not efficient, I don't think this should be completely dismissed, just needs time to be developed like anything else. And obviously its limitations must be acceptable to the person using the tech. I remember an individual on AM550 radio that was running his dodge V8 off a compressed air system he developed and it was a hybred in that he could shut off all the valves and run as gas after the conversion. He had a large tank in the bed that he filled at gas stations. He range was 25 miles at 25MPH. Interesting fringe item, older guy if I remember, I have been trying to find him listed on the internet but couldn't find anything, the guys on the radio who drove with him thought it was dumb and ridiculed him, I would like to see how he did it and controlled it. Another mention of using air has been on cave systems which almost always are blowing or sucking air, an ambient system could be used to take advantage of day to day variations in pressure to produce energy. Interesting stuff but likely a long way off. Cheers Ryan |
02-21-2010, 12:27 PM | #5 (permalink) |
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You'd have to have a thick skin. I see plenty of ridicule, even on this site, for people with different ideas. People will definitely say that 25MPH for 25 miles is not feasible for any practical usage, but I know it's faster than I can pedal for that far, and I'm damn sure not pedaling a Dodge V8.
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02-21-2010, 01:18 PM | #6 (permalink) |
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I would think using compressed air with a gas engine could work ok, as one produces heat as a waste product and the other produces cold.
Another option would be a good size venturi with a compressed air tank to replace a turbo. |
02-21-2010, 02:29 PM | #7 (permalink) | |
Misanthropologist
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There's a great deal of information on this subject crammed into this one page.
Quote:
There's simply nothing inherently efficient or cheap about a compressed air drive system. Even the most anemic and cheap electric drive setups will outperform compressed air in both price and practicality.
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02-21-2010, 02:51 PM | #8 (permalink) |
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If you can use the heat of compression for home heating, and re-warm the air with huge heat exchangers on the vehicle, between expansion stages, you can get some of the same over-unity efficiencies we see with heat pumps. However, the Air Car people ignore the danger of air tanks. Needing no oxygen mixing to release their full energy, they are like high explosive. Historically, air-powered vehicles in mines have had a short range, despite steam-boiler sized tanks.
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02-22-2010, 07:34 PM | #9 (permalink) | |
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