Channeled heat sink and chassis with integrated heat rejecter for two-phase cooling

A channeled heat sink and a device chassis having one or more integral condensing volumes suited for heat rejecters in conduction with two-phase cooling loops. The channeled heat sink includes a base from which a plurality of hollowed fins extend. Each hollowed fin defines an internal channel having walls configured to condense a working fluid from a vapor phase upon entering the channel into a liquid phase upon exiting the channel. The chassis comprises a shell formed from a base coupled to a plurality of walls. At least one condensing volume is formed in the base and/or the walls of the chassis. The condensing volume is configured to condense a working fluid from a vapor phase to a liquid phase as the working fluid is passed through it.