Heat Distiller
Heat Distiller is an artifact that gives you 1 Serenity every 3 turns.
Clarification
It has a counter that increments at the start of your turn. This counter does not reset between combats. Every time it hits 3, it resets and gives you 1 Serenity.
Strategy
Serenity is a great way to use Heat-producing cards without any negative consequences, especially those that produce a lot of Heat, as all the Heat is negated by a single stack of Serenity. Examples include Solar Flair B, Desperate Measures, EMP slug and Hot Compress. Even if a stack only saves 1 Heat gain, it still goes a fair way to keep your ship safe from overheating.
It is possible to use the fact that it carries over from fight to fight with careful play - if you have a fight under control, you may look to stall to end it with this artifact's counter on 2. That way, you'll gain Serenity at the start of the next combat, ensuring that your first Heat card each combat is safe.