The use of heat pipes in personal computers

With the continuing increase of CPU and system power dissipation requirements in personal computers, including notebooks, desktops, workstations and servers, the last three years have witnessed increasing use of and interest in heat pipes in personal computers to meet cooling requirements. The paper reviews heat pipe applications in notebook computers and high end systems. Heat pipe\´s main structure, components, and operation are briefly reviewed to give the readers the necessary background in heat pipes. In notebooks, heat pipe-to-keyboard thermal solutions have been the mainstream thermal solutions used in Pentium^R based notebooks and sub-notebooks, providing about 7 W of CPU cooling solutions. New technologies like the thermal hinge concept, RHE (remote heat exchanger) thermal solutions and roll-bond heat pipes are also reviewed. Testing data on RHE prototypes showed that the technology can provide thermal resistance of 3.66°C/W from the CPU case to the outside ambient. In high performance systems, the conventional heat pipe heat sinks are reviewed first. The heat pipe lid/plate concept is then proposed and reviewed. The heat pipe lid is designed to be an extremely efficient heat spreader or plate and is being developed for high end cooling requirements. Testing data on early prototypes showed that they can achieve a level of 0.07°C/W spreading resistance for a ~3"×5" size heat pipe lid. Finally, the paper summarizes the future outlook of heat pipes for cooling of personal computers