The lore of The Great House of IO says that they harnessed the heat of io to make power and thrust. Unfortunately, consuming heat would be pretty exclusively a good thing. As such, instead, enter the Advanced IO Stirling Engine (AISE); basically they act as rate-limited one-ways for heat, using the heat differential to make power; these can be large, owing to IO having a significant amount of room on IO.
Implementation:
The input heat and output heat must be 2 separate networks
The AISE has a little bit of heat storage buffer on both ends; the hot side is effectively an input, cold side is output
Power is only generated when there is enough of a heat difference between hot/cold sides, and only at a certain rate (effectively limiting the heat transfer rate)
Heat generated is more than was put in (by what amount is up for discussion)
When full of power, the ASE allows heat through at a limited but un-multiplied rate
I think this is more balanced as:
-you want big hot on one side and big cold on the other, which incentivizes routing all heat through a single structure, which can be exploited by your enemies to disconnect all your cooling from all your hot stuff with less guesswork - Just Shoot The AISE!
-rate limiting the heat makes for spice
-if your heat dissipation is shot up you also suddenly don't have power, thereby increasing the criticality of your radiators/tcm launchers (at least on the cold side)
there may be different sizes of AISEs but that's for you to implement.