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Old 02-21-2010, 01:29 PM   #7 (permalink)
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Join Date: Sep 2008
Location: Sterling, VA
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BORK! - '89 Volvo 240 DL Wagon
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There's a great deal of information on this subject crammed into this one page.
The environmental and cost claims by Air Car advocates are even more exaggerated. Air compressors, even up to 100 times the size that any local station would consider purchasing, are extremely inefficient. In principle, it may be possible to compress air to 260 bar at about 75% efficiency, but 12% to 30% is more typical. The small (5.5 hp) compressors that individuals might purchase for charging their tanks overnight at home will consume about 60 kWhr of energy to fill the tanks with about 9 kWhr of (gross) energy. Thatís about 15% efficiency. At $0.12/kWhr (expected US mean price in 2010), consumers would be paying $7.20 to fill their tanks. Thatís like paying $13/gal to fill a Prius.
Compressed Air Energy Storage (CAES)

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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