Ships are standard-equipped with cooling systems that collect heat and transport it to the heat vents. These vents feature heat-conductive fins that radiate the heat out into space. This allows a ship to maintain heat levels within sustainable operational ranges.
A Heatsink Launcher can be equipped to transfer internally stored heat to a disposable sink which then ejects it from the ship. A better power plant improves heat efficiency. Then the baseline running temperature will be cooler and the heat vents are used less.
Radiation is the final method of heat transfer, and is how we receive heat energy from a star through the vacuum of space. For example if you heat an iron ingot hot enough it radiates heat. Initially this is Infrared and eventually if you continue to heat it then it will glow white hot. That glow sends heat energy away from the ingot as photons of light.
A ship's radiators glow orange when they are actively 'venting' heat. That heat energy is emitted as infrared all the way to the visible spectrum. This is why the sensors use the infrared spectrum to track other ships, because ships will always generate heat and thus need to expel that heat.