Heat Sink Capabilities and Limitations: A Hierarchical Evaluation of Leading Thermal Technologies

This paper discusses the pros, cons and performance capabilities of a variety of thermal solutions including: conductive heat sinks, heat pipe assisted heat sinks, and pumped single solutions. The goal of the paper is to map performance regimes for various thermal solutions that will quickly allow thermal designers to select the appropriate technology for their requirements. The paper presents current technologies in a progressive manner discussing performance capabilities and limitations. Although innovative designs exist in every class of sink that push the capabilities of the technology there are basic limitations that define the overall performance envelops, and thus the need to move up the performance heirarchy to the next performance level. The limitations to conductive heat sinks are addressed and correlated to the industries transition to heat pipe assisted heat sinks starting with notebooks and currently progressing into the desktop segment. A brief section addresses solid metal conductive heat sinks with discussions focused on the physical limitation set by conduction which limits overall heat sink volume which in turn can be correlated to a maximum power that can be dissipated in standard commercial applications. The analysis presented and conclusions will be correlated to CPU power and the markets adoption of heat pipe assisted heat sinks. A more extensive section is devoted to heat pipe assisted heat sinks their pros, cons and physical limitations. A similar analysis as discussed in the first section of the paper outlines the anticipated transition points for pumped single phase solutions.   This paper was also originally published as part of the Proceedings of the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems.