Hiding inside a star

[Teleros]

The three main requirements are capacity, efficiency and of course how quickly you can dump unwanted heat into your heatsink. That's why David Brin used a laser - having the rest of the universe act as a heatsink means you have for all intents and purposes unlimited capacity.

Problems
- I'm not sure how important the position of your starship is though - as I recall, the deeper into a star you go, the longer it'll take for any one photon to escape (due to the increased chance of collisions), which will affect how well your laser works. That energy will also heat up the environment you're in as well, but to what extent I don't know - I don't know anywhere near enough about the physics involved. Position will also mean various other problems, even if you're using an internal heatsink (eg pressure).
- You're going to need ridiculously efficient machinery to minimise the waste heat produced, whatever type of heatsink you use. Obviously the less hard sci-fi the setting is the easier this becomes, but bear in mind the knock-on effects too.
- There will always be some waste heat, so you can't expect to stay in there forever: even if the machinery can survive inside a star for years, if your ship's reaches boiling point in just a month then you're in trouble.
- As Starglider pointed out, dumping the excess heat into hot plasma can lead to fusion, which in most lighter elements creates more energy. Fusing heavier elements results in a net energy loss, but I've no idea how practical this is, or what the limit is even if you can.

[bobnik]

The Mote in God's Eye (Niven/Pournelle) had a couple ships muck about in the outer layers of a red giant for a couple of days. Their energy shields ("Langston fields") were basically enormous energy sinks that could rob energy from any input, kinetic, plasma, or photonic. However they had a limit as to how much energy they could store before catastrophic failure, and had to radiate the energy away at a controlled rate much less than the input rates in battle or in the star.