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Energy content of air at pressure

  1. Aug 1, 2014 #1
    Hi can anyone point me in the direction, or tell me how you can calculate the energy content of air at a given volume and pressure? Lets say 1 bar and 1 litre. Also is there a calculation for working out the energy available in that figure to perform work? Thank you.
     
  2. jcsd
  3. Aug 1, 2014 #2

    russ_watters

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    Staff: Mentor

    At a basic level It's just pressure times volume. How much you can harness depends on the method.
     
  4. Aug 1, 2014 #3
    Ok, is it calculated in bar ? And it the answer in Watts?) Thanks, Im having trouble finding it anywhere.
     
  5. Aug 1, 2014 #4

    russ_watters

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    Watts is power, not energy, but if you want SI, it is just N/m^2 * m^3 = N-m.

    No offense though, but I'm sensing you might be in over your head on something here. If you give us some info on what you are trying to do, we might be able to be of more help.
     
  6. Aug 1, 2014 #5
    No offence taken, I didn't mention it could be a flow rate of 1 litre per second at 1 bar, hence the possible power conversion. For now im just trying to find the energy content if contained and not flowing.The actual question i'm trying to solve from this is 3 bar pressure, 0.265 Litres per second. Thank you.
     
  7. Aug 1, 2014 #6

    russ_watters

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    OK, so can you do it with what I've given you?
     
  8. Aug 1, 2014 #7
    So 3 bar =300,000 N/m^2 (1 bar = 100,000N/m^2) * 0.00026500 m^3 (1Litre = 0.0010000 m^2) = 300Nm ?)))
     
  9. Aug 1, 2014 #8

    russ_watters

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    Correct!
     
  10. Aug 1, 2014 #9
    Thank you)) to take it one stage furthur , I just times by the distance the force is used over and divide by time for the power? So I get 300Nm x 0.20M /1s = 60 watts?)
     
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