Would heat sinks work in space?

Personally I am more skeptical about the note next to the shield generator claiming the star destroyer has an energy source that is roughly equivalent to a medium-sized star.

what, you mean converting the ship's heat energy to electrical so that it can go back to heat in the first place? that can be done with the same principal as refrigeration w/ a sterling engine on the coils. Then, the flashlight could emit the same infrared photons as say a thousand-dergee blackbody without being itself anywhere near that hot.