Comment by HPsquared
3 days ago
Something like a vacuum flask, I imagine. Vacuum is a very good insulator already and you minimise radiative heat transfer (infrared glow) by making a surface shiny and metallic usually (low emissivity)
3 days ago
Something like a vacuum flask, I imagine. Vacuum is a very good insulator already and you minimise radiative heat transfer (infrared glow) by making a surface shiny and metallic usually (low emissivity)
Good electrical conductors are also good thermal conductors. It's a fun system challenge to minimize what needs to be hot, but some things will have to get hot. It could be reduced to a photodiode, transistor, and a relay.
But how do you get the power to the heater in a compact way?
One notable exception to this is superconductors. One might naively think that because superconductors have zero electrical resistance, they also have zero thermal resistance. But this is wrong (sorry, Larry Niven)! The superconducting charge carriers (Cooper Pairs) have zero entropy, so they can't carry heat. Thermal conductivity of a superconducting material drops when it becomes superconductive.
I believe high Tc superconductors have been used (or at least proposed to be used) as current leads for carrying current into low Tc superconductors from somewhat higher temperature normal conductors.
Diamond is my favorite exception to this, one of the best thermal conductor and insulators.
Boron nitride too. I guess the thermal vibrations transmit well through a stiff microstructure.
If you have to bring your own vacuum flask, don't you lose half the benefit of doing it in space?
Isn't the primary benefit the lack of gravity?
You can reduce metals through vacuum pyrolysis at much lower temperatures without a reducing agent if you have a vacuum. This could make industrial scale processing of steel relatively easy on the moon.
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I imagine you just need the flask part, the vacuum is rather easy in space.