Why is charcoal good for thermal storage? I would imagine the powder would need to be tightly packed to be effective. Do you have a link to more information about it?
Discussion
my hypothesis is that as it isn't liable to burn until about 4000 degrees, in a metal case it is a massive thermal sink
what makes a "thermal store" is about its latency between absorbing and re-emitting the heat it absorbs... the problem with metals is they are conductive, and thus they re-emit fast as the heat goes in, and then goes out
a decently packed mass of charcoal powder has a lot of air spaces between the dust and the carbon itself is a poor conductor, but it is not a bad conductor, and it can hold a very high temperature, and thus it acts as a store
put it this way, the same thing applies to electricity, i think... a super capacitor is the highest capacity electrostatic store currently known, and is literally two chunks of powdered charcoal interfaced by a thin layer of insulating glass, which can withstand the thermal effect of the electrostatic discharge
i think if it holds and leaks electricity efficiently it probably also holds and leaks heat the same way
I'm having a hard time imagining how to effectively charge the charcoal with heat.
that's ok, i put the idea out there, it's not hard to test with something like an old, shitty aluminimum pot to test how much it can raise the temperature of a container of water you drop it into
you can compare it also to boiling water in same pot, or fill it with some oil, and see how much it raises the temp in the same conditions