Easy way to find the potential energy in compressed air

[Scott Davies]

I have a .81 Cu. Ft. cylinder which is at a static pressure of 80 Psi. What is the easiest way to calculate the Potential Energy of the compressed air?

 

[sophiecentaur]

Hi and welcome to PF.
You would need to specify the conditions how the work is obtained from the compressed air because the conditions for the expansion will make a difference. Is it Isothermal or Adiabatic expansion?
Is this basically a question about the possible energy in an explosion, if the cylinder ruptures, for instance? A bit more context would help to get the answer you need.