No moving parts, except maybe an external fan. Coolant boils, convects to the wall of the vessel, and condenses, giving off heat.
If you google 'heat pipe' , you can find
a good how to
and
a mass produced one too .
My plan is to use a flow restrictor in one side of a coolant loop system, instead of a plain vessel. This will force liquid up the pip on the opposite side, developing a head which will force flow without a pump. Since forced convection gives a higher temperature gradient at the wall, this should make for better heat transfer out of the system.
The operating temperature range of the system is limited by the strength of the pressure vessel- too hot = too much pressure = boom. It will not boil dry- as the pressure increases, the boiling temp increases as does the proportion of liquid to vapor.