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Air Car Argument

Page history last edited by PBworks 17 years, 5 months ago

Air Car Argument in alt.energy.renewable

 

From: Hoggle - view profile

Date: Wed, Oct 4 2006 4:34 pm

Email: "Hoggle"

Groups: rec.autos.tech, alt.energy.renewable, sci.environment, alt.global-warming, sci.environment

Not yet ratedRating:

 

 

 

BobG wrote:

> This site has a table of energy density by weight and volume and

> compressed air is worse than batteries. (Hint... most air compressors

> I've seen are big noisy 220V several HP contraptions and they huff and

> puff and finally shut off at a whopping 150 psi.)

> http://xtronics.com/reference/energy_density.htm

 

 

Your ref:

Compressed Air (no pressure indicated) 17 Wh/l 34 Wh/kg

 

http://en.wikipedia.org/wiki/Energy_density

"compressed air at 20 bar" 0.27MJ/kg

 

 

1MJ/Kg is roughly 278Wh/kg

1 bar is about 14.5psi

 

 

Thus the limit appears to be 75Wh/kg at 290psi (about 3 times that of a

lead/acid battery)

 

 

However:

http://www.futurepundit.com/archives/000129.html

"the air is both cooled to minus 100 degrees Centigrade and compressed

to 4,500 pounds per square inch"

 

 

http://www.activepower.com/files/whitepapers/TACASWhitePaper.pdf

"TACAS begins with compressed air stored in conventional gas cylinders

or pressure vessels. In order to meet the system's performance

targets, it is necessary to store compressed air at high pressures,

ideally 4500 pounds per square inch (PSI) or more. These pressures are

routine for Self-Contained Breathing Apparatus (SCBA) compressors and

fill stations used by fire departments and diving operations. Gas

cylinders rated up to 6000 PSI are widely available."

 

 

This is one of the resulting products - an 85kW (for 15 minutes) DC UPS

supply

http://www.activepower.com/files/products/AP_Spec_CoolAir.pdf

 

 

A car needs to be able to run for 300+ miles at 60mph using the power

equivalent demand of 30-50kW, a total energy storage/delivery of about

200kWh. Thus a unit only 10 times more efficient could power a car.

 

 

I realise that the UPS shown is 1270kg on its own, but it has redundant

extras to maintain storage and produce millisecond response times that

a car storage/power unit would not need. The proposed system could

easily be designed to weigh less than an engine and fuel tank combined.

 

 

So try not to write the system off with so little understanding of the

facts.

Comments (1)

Answer Blip said

at 12:59 am on Feb 2, 2010

We are in need of people to answer our communities questions about car repair on various models if someone from your community would like to help out http://www.answerblip.com/car-information-repair-and-facts

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