The Air Car Scott McNally Chemical Engineering The University of Texas Fall 2007

Outline The Cars Air Tanks Thermodynamics –Does it make sense? –Is it even possible? Summary and Conclusion

The Engine Compressor efficiency: 80-90% These engines are compressors in reverse

MDI: Moteur Developpment International Weight: 750 Kg Max load: 500 Kg Range: 150 miles Top speed: 68 mph Recharge time: 3 minutes

Filling the Tanks Costs $2 in electricity Filling stations –3 minutes using volume transfer –These stations don’t exist Home compressor –4 hrs in Europe –8 hrs in U.S.

Thermodynamics 300 Liters at 300 Bar –Full tank weight: 200 Kg –43,600 Btu required for filling –40,000 max output Gasoline: 110,000 Btu/Gal Equivalent: 0.4 gallons of gasoline

Thermodynamics Honda Civic Hybrid: 45 mpg, 1100 kg –Gas engine: 20% efficient At 100% efficiency: 225 mpg 0.4 gallons: 90 miles Advertised numbers are flawed Tank size needs to be doubled –Increase weight by 200 kg –Not a big deal

Thermal Efficiency High thermal efficiency –Power plant: biggest loss at 50% –Transmission line loss: 7% –Compressor: 10-20% –Air engine with regenerative braking: 170% Impossible –Overall efficiency: 40% –Electrical efficiency: 70%

Summary - Benefits Cheap –3,500 euro sticker price –A few dollars to fill up and maintain –Free Air Conditioning Higher thermal efficiency

Summary - Drawbacks Less safe: Fiberglass and glue Low power, tank bleed off Shorter range Infrastructure problem

Conclusion Possible Good for city driving Short range forever Not likely to be successful in U.S.

References The Air Car Moteur Developpment International. 17 Nov Thehttp:// World’s First Air Car Popular Mechanics. 17 Nov omotive/new_cars/42...

Questions?