A system and method for providing and using wickless capillary driven constrained vapor bubble heat pipes for application in rack servers are disclosed. An example embodiment includes: a base structure; and a rack column supported by the base structure, the rack column in thermal coupling with a heat-generating device, the rack column containing a constrained vapor bubble (CVB) cell cluster including a plurality of cells in thermal coupling with the heat-generating device at a first end in an evaporator region and in thermal coupling with the base structure at a second end in a condenser region, each cell of the plurality of cells having a wickless capillary driven CVB heat pipe embedded in the cell, each wickless capillary driven CVB heat pipe including a body having a capillary therein with generally square corners and a high energy interior surface, and a highly wettable liquid partially filling the capillary to dissipate heat between the evaporator region and the condenser region.