Another potential drawback is that thereвЂ™s little design flexibility in the z-direction. Traditional Two-Piece Vapor Chamber ( & Celsia)ДЄs mentioned earlier, the increased cost of this design sometimes limits its incorporation into thermal solutions. For lower power applications, perhaps requiring only a single, small heat pipe, or those where heat must be effectively transported, heat pipes still maintain dominance due to their low cost and design flexibility. They were used both for heat transport, for which they still have an advantage, and for heat spreading, typically using multiple pipes in close proximity to one another.

Structural Design & CostДЇor decades, heat pipes have been the default two-phase device of choice for thermal engineers due largely to the cost difference relative to vapor chambers. In this sense, heat pipes and vapor chambers are the same thing.ДЇor simplicityвЂ™s sake, IвЂ™ll be focusing on the most common type of two-phase device: an all copper vessel, using a sintered copper wick structure with water as the working fluid. As heat is applied to one area, the liquid turns to vapor and moves to an area of lower pressure where it cools and returns to liquid form whereupon it moves back to the heat source by virtue of capillary action. Liquid (usually water) is added to the device and vacuum sealed at which point the wick distributes the liquid throughout the device. A wick structure (sintered powder, mesh screens, and/or grooves) are applied to the inside walls of an enclosure (tube or planar shape). It probably goes without saying, but the operating principles of all two-phase devices are identical. But, which one is likely the best choice? In todayвЂ™s blog IвЂ™d like to do a topline overview of structural differences and thermal design considerations between these very similar yet somewhat unique two-phase devices. Regardless of the reason, most thermal engineers are going to need a two-phase cooling solution using either heat pipes or vapor chambers on numerous projects with which they are involved. Component power /density necessitates heat be moved to a remote location more than 40-50mm away from the heat source.Transitioning to a solid copper heat sink, in whole or in part, adds too much weight and in some cases too much cost.Enclosure size and/or airflow canвЂ™t be increased.Keep out zones prohibit a larger heat sink (thicker base, added fin area, etc.).

At some point in a thermal system design project it may become apparent that the tried and true methods of increasing thermal efficiency вЂ“ solid base, fin & fan вЂ“ just arenвЂ™t sufficient.

All copper heatsink