An experimental study on applying miniature loop heat pipes for laptop PC cooling

A novel miniature flat loop heat pipes (MFLHPs) with rectangular shaped evaporator was developed and designed for laptop cooling, by considering the operating principle of the LHP system and its ability to carry larger amounts of heat over long distances than conventional heat pipes. The effect of the length of the evaporator and the connecting pipe was investigated. The results showed that the length of the connecting pipe and the length of the evaporator are the main factors affecting MFLHP start-up. The thermal performance of a MFLHP increased with the increase of the length of the evaporator. There was an optimal length of the connecting pipe to make a MFLHP operating well. Finally, a heat sink attached to a MFLHP was developed for cooling a CPU of notebook, the thermal design power (TDP) of which was 45W. The results showed the CPU heat sink with MFLHP had good performance and satisfied laptop cooling requirements. Compared to the conventional heat pipe solutions, the MFLHP solution was able to keep CPU temperature stable with the increase of heat loads and cope with the higher power dissipation, offering the potential to make a lighter heat sink.