In reply to Michel Jullian's message of Fri, 11 Jan 2008 17:56:31 +0100: Hi, [snip] >I understood the sentence as referring to some pneumatic version of >regenerative braking, but >admittedly it was unclear. > >What amazes me with this compressed air energy storage thing is that it is so >dead simple, isn't >there a catch somewhere? > >Let's see how much energy they store in their 300 litres at 300 atmospheres, >it's P*V isn't it? > >P*V= 300*10^5Pa * 0.3m^3 =~ 10^7 J = 10^7 W.s = 10^4 kW.s > >Mmmm... only about 10000/3600 =~ 3 kWh???? > I think it depends on how the expansion is done. If adiabatically, then you are correct, if isothermally, then extra energy can be absorbed in the form of heat from the environment, just as heat is lost to the environment during compression. In practice, the efficiency will probably be somewhere between the two methods.
Regards, Robin van Spaandonk The shrub is a plant.
