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> Matthew McMahon says -
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> Subject: The Air Car - zero pollution and very low running costs -
> gizmag Article
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> >
http://gizmag.com/go/7000/
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> French designed. Indian made.
> 300 km range claimed.
> Approx 10% of petrol running costs claimed.
> E1.5 per 300 km fill.
> 68 mph toppppp speed.
> Lessee.
> E1.5 ~~= $US2? ~= $NZ3.
> Approx 2 litres petrol at NZ prices.
> So 150 km/litre or about 375 mpg-US or 425 mpg imperial.
>
> No mention of pressure used.
> 90 m^3 of gas said to be stored.
> You'd be (very) lucky to get 1 m^3 of storage in a small car so that's
> 90+ atmosphere =~~ 1500 psi or 9 MPa.
> Probably double that.
> Would need a very many stage expansion motor to handle that
> efficiently.
>
> Very very (very ...) roughly using expanded energy equivalent, 90 m^3
> at 1 atmosphere = 90 m^3 x 100 kPa = 9 MPa energy.
> 9 E6 /1000 kW/W /3600 hr/sec = 2.5 kWH = about 10% of what I
> calculate the cost would buy in energy equivalent electricity. And 2.5
> kWh is utterly insufficient for the task as 20 kWH (see below) is
> rather skimpy. Possibly a missed decimal somewhere in my figures but
> ... .
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> >From an electricity point of view. $NZ3 buys about 20 kWH of
> electricity or the same energy content as 2 litre of petrol.
> 150 km on a litre of petrol given equivalent energy content is "rather
> good".
>
> I very strongly suspect that their energy costing claims are
> fallacious.
> I'd be happy to be proven wrong.
>
> E&OE as always
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> Russell
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