Numerical study and analysis on lowering the resistiveness of lateral heat spreading in a passively cooled notebook

The current generation's demand for laptops is trending towards low-noise, cooler, and high-performance systems. For low noise, fanless systems are preferred, which depend on the surface area of the system for cooling through natural convection. Thermal solutions in fanless systems are limited to the printed circuit board (PCB) area and have a hotspot in the same region. To increase cooling capability for maintaining low temperatures at high power, heat needs to be spread to the relatively cooler locations of the system. The better spreading can be measured by resistiveness in lateral heat spreading (RLHS). The lower RLHS would help to increase power capability at lower temperatures. To aid this spreading of heat, an efficient heat transport mode is designed, which increases the power capability by ~2W in the same fanless system. Heat is transported from the System on Chip (SoC) region to the palmrest area of the notebook via multiple heat pipes. As the palmrest area is typically cooler, it serves as the condenser of the heat pipe and enables effective transport of the heat through the heat pipe without any fans. The numerical study is done using a finite volume method (FVM) in computational fluid dynamics (CFD) with design optimization to get maximum cooling capability. The simulations and results are presented only for the base of the laptop without the display, and cooling enhancement up to 2W is seen with better spreading of heat compared to the baseline case.