Suspended nanoparticles as a way to improve thermal energy transfer efficiency

Nanoparticle suspensions have demonstrated superior heat transfer properties and hence appear to be a strong contender to become next generation coolants. While the presence of particles enhances thermal conductivity, they also contribute to increase the fluid viscosity. The latter will lead to demand more pumping power in convective systems, hence questioning the overall economy of the concept. This paper presents the recently obtained thermal conductivity and rheology data for alumina (Al₂O₃) and titania (TiO₂) nanoparticles suspended in ethylene glycol in the temperature interval of 20-90°C and particle concentrations of 0-8wt%. Although the thermal conductivity enhanced by up to 14%, a simultaneous increase in viscosity dampens the net advantage of using nanoparticle suspensions as convective heat transfer fluids.