Nanostructuring of Heat Sink Surfaces for Improved Cooling Efficiency

Heat removal from fusion energy systems is a vital issue. In these systems the prevalent heat dissipation technique is forced convection of a cooling fluid (water, helium, etc.) through a heat sink. Improved cooling efficiencies are needed to keep pace with the projected heat generation trends. Major gains in the efficiency of cooling by forced convection can be realized through controlled nanostructuring of the heat sink surfaces, in order to substantially increase the contact area with the coolant and to transform the laminar flow of the coolant into a turbulent flow. Although pioneering work in this area has introduced carbon nanotubes upon the heat sink surfaces, this project will explore a simpler and more versatile approach: relatively long metal nanowires of controlled spacing and diameter will be grown upon the heat sink surfaces using low-cost scalable techniques. This approach would increase the contact area of hot surfaces with the coolant by two to three orders of magnitude. The turbulence generated in the fluid flow by nanowires would improve the intermixing of the coolant, further benefiting the cooling efficiency. Phase I will validate the merits of nanowire growth upon heat sink surfaces as a commercially viable means of greatly improving the efficiency of cooling by forced convection. Commercial Applications and other Benefits as described by the awardee The technology would address the critical need for heat removal from fusion power generators, which are viewed as major sources of alternative energy with abundantly available fuel. The technology also would address the growing need for heat dissipation in electronic devises, where increasing power concentration is causing a sharp rise in chip-level heat fluxes. The global electronic market for thermal management technologies is estimated at $6.8 billion in 2008, with a compound annual growth rate of 10.3%. Thermal management hardware, the focus of this project, accounts for more than 80% of this market.