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To: familyop

"Recharging the onboard tanks takes about four hours using the car's small compressor, which can be plugged into any wall outlet."

Seriously?!

I am really tempted to look up the energy requirements for compressing air from 0 psig (14.696 psi absolute) to 4500 psig (4514.696 psi absolute) in a Perry's Engineers Handbook, because methinks the horsepower requirements on a copressor charged with this task would be out of sight.

I have a two-stage reciprocating air compressor in the barn that takes air from atmospheric to 150 psig, and it requires a 5 hp electric motor to handle 80 gallons of air (10.7 cubic feet, 0.3 cubic meters). Granted, they're sure to be using a multistage turbine to do this, but the power requirements have got to be out of sight.

I assume France has 240V plugs everywhere? We don't here, of course, and if you've got half the voltage, you need double the amperage. If they have a 20 amp 240V outlet, we'd need a 40-amp outlet to match the net wattage. Net Energy in must equal Net Energy out (Work done to compress the fluid plus and frictional losses. My old rule of thumb used to be 72% mechanical efficiency on a turbine). Energy = Wattage*time.

I just might see if I have my handbook, just for fun.


103 posted on 02/22/2005 4:28:05 PM PST by AZ_Cowboy ("Be ever vigilant, for you know not when the master is coming")
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To: AZ_Cowboy

France is 240V. They also have nuclear power mostly. Delta cost per additional Kw is very low.


127 posted on 02/22/2005 4:51:14 PM PST by buwaya
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