Development of a thermal management solution for a ruggedized Pentium based notebook computer

This paper presents the thermal management analysis of a ruggedized notebook computer designed for reliable operation under extreme conditions. The most stringent constraints for this thermal design are operation at high external temperature and that the computer case is forbidden to have venting holes. These constraints and interior space limitations make airflow and convective heat transfer insignificant inside the notebook cabinet. This work presents a solution in which the heat dissipated, mainly by the CPU, is conducted to the outside ambient. A numerical model of the computer was built and validated. Initially, numerical analysis was carried out to characterize the thermal performance of an 80586 processor based notebook and the results were compared with experimental measurements on an actual system. Then, the model was modified to include a Pentium processor with significantly higher power dissipation. The numerical model includes ICs, PCBs, casing, and power supply boards. Several thermal management strategies were analyzed in order to achieve reliable operating conditions under ambient temperatures as high as 60°C. The analysis provided methods of transferring out the additional heat generated by the Pentium processor using heat pipes connected to a heat dissipating plate and an external fin. These additional components required for cooling were characterized and the proposed cooling system configuration was specified. The results demonstrate that thermal management solutions for notebook computers can efficiently be developed and tested using a validated computational thermal model of the system