2 ms·
Your energy estimation makes no sense whatsoever. The figure you gave is for isobaric expansion, which is an entirely different beastie. Also, he mentions ~100
by TheLoneWolfling 12y ago
Your energy estimation makes no sense whatsoever. The figure you gave is for isobaric expansion, which is an entirely different beastie.
Also, he mentions ~100bar, not ~60 bar.
When I did a first approximation assuming adiabatic expansion, I got ~22KJ.
See https://news.ycombinator.com/item?id=9449086 https://news.ycombinator.com/item?id=9449086
- maho 12y agoYou are absolutely right, I should have used the formula for adiabatic expansion. However, I maintain that the pressure inside the thermos should only be 60atm, since this is the vapor pressure of CO2 at room temperature [1], where the liquid and the gas phase are in equilibrium. This is like the butane in a lighter: Butane evaporates at room temperature, but there is an equilibrium between liquid phase and gaseous phase when the pressure is higher. Using 60bar and the adiabatic formula, I get 12.5kJ of energy. [1]: http://en.wikipedia.org/wiki/Carbon_dioxide#Physical_properties http://en.wikipedia.org/wiki/Carbon_dioxide#Physical_propert...
- TheLoneWolfling 12y agoOk, that works. I was just going from the article's figure of 100atm. I probably should have double-checked that figure.