Re: [PSUBS-MAILIST] Energy within gas

[Ian Roxborough <irox@ix.netcom.com>]

Hi,

Since nobody else has answered I'll have a shot.
Be warned, my physics hasn't been used for
a couple of year and is rusty...

Pressure = Energy / Volume

Energy = Pressure * Volume

  3000psi * 6900 = 20700000 Pascals
  10 liters = 0.010m3

  E = 20700000 * 0.010
    = 207000 Joules

If we want to estimate the power this would provide

  Power = Energy / Time

So if we use up the energy over, say, 15 minutes

  Power = 207000 / 15 * 60

        = 230 Watts
  or slightly under a third of a horse power.

These calculations (if remotely correct) probably only
apply in outerspace where the pressure difference been
the tank and exhaust is really 3000psi, but if you where
1000 feet under the ocean the tank and exhaust pressure
difference would be only 2550psi.  

Compressed air doesn't seem to be a useful way
of transporting energy in a sub.

Ian.

On Wed, 8 May 2002 13:42:31 +0200 (CEST)
Oliver Simmert <osimmert@yahoo.com> wrote:
> 
> I am looking for a formula that tells me how many
> energy is bound within a bottle of preasurized air.
> For example if I have a standart diving bottle
> with 10 liters volume and 200 bar preasurized air in
> it and I pass the air into a steam-engine-like
> cylinder the air will do some work.
> How do I calculate the amount of work in joule or
> kilowatts ?
> 
> Thanks,
> Oliver
> 
> 
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