6 points
Water turning into steam soaks up an enormous amount of heat. I assume that thermal runaway happens somewhere above 100C, right?
CO2 extinguishers work by displacing oxygen, not by cooling.
5 points
The rapidly expanding co2 does get very cold though. It’s not any different from freezing things with compressed air cans.
I don’t hover, know which would absorb more heat per pound though. Someone who knows more math than I can do it though.
7 points
*
If I’m reading Wikipedia correctly, it takes 348 Joules of heat to boil a gram of CO2.
Water is 2257 Joules per gram. As long as you don’t need anything cooled under 100C, water is the way to go for cooling. It’s also a hell of a lot cheaper and easier to deal with than liquid CO2.
