Experimental investigation on solar flat plate collector using alumina nanofluid with tube inserts

Abstract

ABSTRACT The heat transfer and friction characteristics of thermosyphon solar flat plate collector using Al 2 O 3 /water nanofluid as working fluid with helical twist insert and its impacts are analysed. Thermal behaviour, heat augmentation and pressure drop characteristics of the modified collector are compared with those of conventional riser tube collector. Alumina nanofluid of 0.1%, 0.3% and 0.5% volume concentrations are used in riser tube of the solar flat plate collector which has helical twist with rod as insert. Correlations for heat augmentation and friction factor in terms of performance parameters like Nusselt number, Prandtl number and fluid concentrations showed acceptable deviations. The convective heat transfer coefficient varies directly with the volume concentration of Al2O3 nanoparticles in base fluid, conversely increasing the fluid concentration increase the density of the nanofluid leading to increase in pressure drop and friction. Results favour to modified nanofluid collector in terms of thermal performance, higher heat removal rate from absorber plate in solar flat plate collector.