Laminar forced convection of a hybrid water-based suspension of Al2O3 nanoparticles and microencapsulated phase change material (MEPCM) particles through a circular tube was investigated experimentally. In addition, an integral energy balance with scaling estimation is presented to elucidate influences of thermal properties of the hybrid suspension on its internal convection effectiveness. Experimental results show considerable enhancement in cooling effectiveness of the hybrid suspension over the pure PCM suspension, nanofluid, or water. However, the convection efficacy of utilizing the hybrid suspension appears severely outweighed by pressure drop penalty from its drastically increased viscosity with respect to the pure PCM suspension or the pure nanofluid. (C) 2011 Elsevier Ltd. All rights reserved.