I think you could do that, but mass in space is kind of hard to come by. If it wasn't (like if you're on the moon) you could just use the mass for conduction anyway. If you have to ship it up and consume it like that, that's expensive and limiting.

I'm not sure you can practically superheat the ballast without just causing more heat that you have to deal with. Maybe a heat pump works? Something about that feels vaguely wrong.