Although the enhanced thermal conductivity of nanofluids has attracted much attention, their radiative properties have rarely been studied. The present paper quantitatively determined the radiative properties of various nanofluid fuels and their effects on droplet evaporation. The results show that radiation absorption can be significantly enhanced by adding a small amount of nanoparticles such as Al to the base fluid ethanol. The strong absorption of radiation energy by nanoparticles increases the nanofluid droplet temperatures and enhances droplet evaporation rate. (C) 2012 Elsevier Ltd. All rights reserved.