Experimental and theoretical investigation on the effects of lower concentration CeO2/water nanofluid in flat-plate solar collector

Abstract

Heat transfer characteristics of solar flat-plate collectors are improved by applying various nanofluids as the heat transfer media nowadays. In the present work, the theoretical and experimental analysis was performed for a flat-plate solar collector operating with water and CeO2/water nanofluid as the working fluids. The flat-plate solar water heater with 100 L per day capacity along with ladder-type heat exchanger having collector area of 2 m2 is fabricated for the experimental study. The average particle size and volume fraction of nanofluids were considered as 25 nm and 0.01%, respectively. The flow rate of water and nanofluid was varied from 1 to 3 lpm, and the efficiency was calculated as per ASHRAE standards. Due to the enhanced thermophysical properties of the nanofluid, it gives better performance and results showing that the maximum efficiency of solar water heater with CeO2/water nanofluid is 78.2%, which is 21.5% higher when compared with the water as base fluid. Also a correlation was developed for predicting the outlet temperature of a flat-plate collector. The maximum collector efficiency of nanofluid was obtained at the optimum mass flow rate of 2 lpm in experimental study. The developed mathematical model was reasonably matching the experimental results with the error of ± 7.5%.