Nanoparticles to keep electronics from overheating

Power dissipation, chip power consumption, and heat flux in electronic devices has been steadily increasing over the past decade, creating a need for improved methods of cooling them.

University of Malaya researchers have developed liquids containing nanoparticles that could help devices stay cool and keep them running.

Nanofluids are made of metallic nanoparticles that have been added to liquid such as water. But there are many different kinds of nanofluids, and past research on their coolant abilities has been limited. To help sort through them, Rahman Saidur and his team set out to determine which ones might work best.

Using microchannel heat sink to simulate the warm environment of a working computer they analysed three nanofluids for the traits that are important in an effective coolant. These different nanofluids consisted of water as a base fluid, with 0.4 to 2 vol % of copper oxide (CuO), aluminium oxide (Al₂O₃), and titanium dioxide (TiO₂) nanoparticles.

The results generally showed that thermal resistance decreases as the volume fraction of nanoparticles is increased. The CuO-water nanofluid was found to be the best coolant in terms of both minimising thermal resistance and maximising pressure reduction. The energy efficiency of the heat sink increases as the volume fraction of nanoparticles increases. A maximum energy efficiency of 98.9% was obtained using the CuO-water nanofluid (at 2 vol %). The Al₂O₃-water and TiO₂-water nanofluids (also at 2 vol %) produced a maximum energy efficiency of 77.5% and 68.4%, respectively. The lowest exergy losses were: 19.2, 20.9, and 25.1 W for TiO₂-water, Al₂O₃-water, and CuO-water nanofluids (all at 0.4 vol %), respectively. The dimensionless friction factor was reduced as the nanoparticle volume concentration increased. Also, the pumping power increased (to a high of 0.0173 W) as the mass flow rate increased.

The findings have been reported in the ACS journal Industrial & Engineering Chemistry Research. The research was funded by the Ministry of Education Malaysia.