HEAT TRANSFER PERFORMANCE OF SILVER/WATER NANOFLUID IN A SOLAR FLAT-PLATE COLLECTOR

An experimental study is carried out to investigate the heat transfer characteristics of silver/water nanofluid in a solar flatplate collector. The solar radiation heat flux varies between 800 W/m(2)and 1000W/m(2), and the particle concentration varies between 0.01%, 0.03%, and 0.04%. The fluid Reynolds number varies from 5000 to 25000. The influence of radiation heat flux, mass flow rate of nanofluid, inlet temperature into the solar collector, and volume concentration of the particle on the convective heat transfer coefficient and the collector efficiency are studied. Both parameters increase with increase in the particle volume concentration and flow rate. The maximum percentage increase obtained in the convective heat transfer coefficient is 18.4% for the 0.04% volume concentration at a Reynolds number of 25000. An increase in the performance of nanofluid is also witnessed when compared to the base fluid, which has a strong dependency on volume concentration and mass flow rate.