Have suggestion for balance. Reactors must use more coolant and ingots to work , 30% more of ingot and coolant for 10 min of reactors work will by good, player will have more work to do for reactors energy.

Let the generated heat accumulate. And then you need to use heat sinks to disperse them (space only). In the atmosphere, the heat would dissipate by itself

If I were to do that, I'd tie into Thermal Mechanics, which would make that a dependency (tbh, its one of my top 50 'always on' mods, and I think everyone should use it). Thanks for the suggestion, I'll think about it.

So they work together like I said or maybe they are two separate 'types' of heat?

They are currently Two separate things, Neither has an affect on the other. But I'm looking at maybe integrating Thermal Mechanics so that the radiators/exchangers do things to my mod

Thermal Mechanics is Grid based, as in, damages the grid, but not the player. Hazard Mechanics is (currently) Player based, which damages players, but not grids.

I think that this mod should only effect player ships, that way AI mods don't have their ships failing

The damage range for the reactors is not manageable, designing a ship where the reactor is around 7-10 blocks away (even shielded) seems excessive.