Electronics cooling using a vapor chamber is a fairly common design choice. Cooling electronics using vapor chambers are subject to the following guidelines:
Power Handling Capacity
Vapor chambers can have the same power handling capacity as multiple heat pipes; from a few watts to over a kilowatt. However, if one heat pipe can meet thermal and physical requirements, it’s probably cheaper to use them – depending on post-production operations like machining. That’s why a move to vapor chambers from heat pipes usually involves applications with higher power and/or higher power densities. Anything less and heat pipes may suffice.
Power Density Capacity
Vapor chambers are particularly well suited for electronics cooling applications where power density is high – roughly above 20 W/cm2 yet below 500 W/cm2. In these situations, it’s usually critical that heat is spread quickly to a larger surface area.
Shapes & Dimensions
The traditional method for producing vapor chambers begins with two stamped plates, mirror images of each other, that eventually get diffusion bonded together. This gives the designer enormous leeway in the X and Y dimensions. Length and width max dimensions are governed by press and furnace size as well as application requirements. Consequently, you typically don’t find vapor chambers over around 300 x 400mm.
Two-piece vapor chambers made of two stamped plates are generally not bent post stamping. Any small ‘steps’ or bends are done as part of the stamping process. However, one-piece vapor chambers that start as a tube are bend post-production in the factory. While band radius changes somewhat depending on vapor chamber width, thickness, and location of the bend, a typical bend radius is on the order of 7mm for smaller vapor chambers to 12mm for large ones. For more information, see the last section of this article: vapor chamber dimensional design limits.