We've already seen desktop PC cases that use their side panels as heatsinks thanks to an elaborate network of heat pipes. According to The Inquirer, notebook contract manufacturer Compal has now developed a notebook cooling system based on a similar concept.
Where current notebooks rely on conventional heatsinks as well as noisy, high-speed fans to cool their processors, Compal's design makes use of the display lid to dissipate heat. The concept sounds easy enough, but the tricky part is transferring heat between the notebook body and the lid. In this case, Compal is using a combination of heat pipes, a metallic heat-conductive hinge, and a "big aluminum or carbon plate" on the back of the screen.
The Inq says this novel cooling system allows a processor with a thermal envelope of up to 17W to be cooled passively. For higher-power CPUs, a combination of lid cooling and conventional fan cooling can be used.