Effects of CuO/water nanofluid on the efficiency of a flat-plate solar collector

Solar water heating is an effective method for heat demands in domestic applications. Solar collector is a main component of any solar water heating system. In this work, the effect of CuO-water nanofluid, as the working fluid, on the performance and the efficiency of a flat-plate solar collector is investigated experimentally. The volume fraction of nanoparticles is set to 0.4% and the mean particle dimension is kept constant at 40 nm. The working fluid mass flow rate is varied from 1 to 3 kg/min. The experiments are conducted in Mashhad, Iran with the latitude of 36.19. The experimental results reveal that utilizing the nanofluid increases the collector efficiency in comparison to water as an absorbing medium. The nanofluid with mass flow rate of 1 kg/min increases the collector efficiency about 21.8%. For any particular working fluid, there is an optimum mass flow rate which maximizes the collector efficiency. Adding nanoparticles to a base fluid produces a nanofluid which has enhanced thermal characteristics compared with its base fluid. (C) 2014 Elsevier Inc. All rights reserved.