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Wind power?
David Jenkins - 4/1/08 at 09:09 AM

LINKY

Mind you, I haven't listened to the commentary (no sound at work) but it can't be too efficient, when you consider the amount of energy required to compress air.

No pollution while running, of course.

matt_claydon - 4/1/08 at 09:17 AM

Figures don't add up for me.

1.5 euros would buy you about 10kWh of electricity. Even assuming 100% compression and decompression efficiency this would only allow you to travel at (as a guess) 40mph for 1 hour.

Also if you want to put that much energy into the tank in say 6 minutes you'll need a compressor running at 100kW!

dan__wright - 4/1/08 at 10:49 AM

quote:
Originally posted by matt_claydon
Figures don't add up for me.

1.5 euros would buy you about 10kWh of electricity. Even assuming 100% compression and decompression efficiency this would only allow you to travel at (as a guess) 40mph for 1 hour.

Also if you want to put that much energy into the tank in say 6 minutes you'll need a compressor running at 100kW!


or a very very big tank

tks - 4/1/08 at 01:06 PM

I have no idea about the real saving figures but there are savings to be made.

- no heat
- no noise
- no gearbox
- no clutch
- brakes?

also i think it has valves sow that the pistons produce air (pressure) while braking / lifting off etc. so you go to the tankstation to compensate our losses of air. not the complete amount what you use.

i think it works! the video says 200km between refuels

Tks

David Jenkins - 4/1/08 at 01:09 PM

I think that its greatest benefit would be the reduction in pollution in cities such as Calcutta, Bombay, etc - which is probably why it's an Indian/French partnership that has built it.

This assumes that it isn't recharged with a petrol-driven compressor in some back street at 2:00am...

[Edited on 4/1/08 by David Jenkins]

David Jenkins - 4/1/08 at 04:08 PM

I bet Gordon's already thinking of ways to tax them!

matt_claydon - 4/1/08 at 05:14 PM

To put compressed air into perspective as a means of energy storage, petrol has an energy density of 49.9 MJ per kg. Compressed air at 100 Bar has about 1.25 MJ per kg.

However the recovery efficiency from compressed air is over 60%, probably double what you get from a petrol engine, but even taking that into account petrol is 20 times better.

I'm sure this technology has a market but it's not in volume-produced passenger cars! As tks said, there are some great advantages, but they are outweighed for most uses by the inability to carry much energy around with you.

segan2b - 4/1/08 at 05:14 PM

Is it a scam?

The physics don't seem to add up!