Abstract: A self contained heat exchanger useful for reducing the operational temperature of a solid state device utilizing mixtures of two or more coolants within a hermetically sealed chamber or chambers. The present invention includes embodiments that are useful for removing heat from a semiconductor electronic device. The present invention provides a low boiling point coolant that boils at the operational temperatures of the semiconductor devices to agitate a higher boiling point coolant that remains in liquid state. Movement of the higher boiling point coolant is instrumental in uniformly transferring heat from the heat source across metal radiator surfaces due to the excellent surface contact of the heat rich high boiling point liquid. The chamber surface then uniformly radiates the heat into the surroundings. At equilibrium, boiling action of the lower point liquid coolant and condensation on the metal surface create recirculation paths within the present invention that enhances heat transfer.