In this work, an experimental study is carried out to examine the cooling performance of a minichannel heat sink using water-based suspensions of alumina nanoparticles (nanofluid), and/or microencapsulated phase change material (MEPCM) particles in terms of the averaged Nusselt number (NU) over bar (itd), the wall temperature control effectiveness epsilon(Tw), and the averaged thermal resistance control effectiveness epsilon(Ravg) for the relevant parameters in the following ranges: the Reynolds number, Re = 133-1515; the mass fractions of the nanoparticles and/or MEPCM particles dispersed in the water-based suspensions, omega(np) or omega(mepcm) = 0-10 wt.%; and the heating power. The heat sink was fabricated from copper with 10 rectangular minichannels which were maintained at a uniform base heat flux. The resulting experimental data for the various effectivenesses of using the water-based suspensions formulated in the minichannel sink were found well correlated with the relevant dimensionless parameters in, general forms. (C) 2013 Elsevier Ltd. All rights reserved.