Effect of nanoparticle shape of Al2O3/Pure Water nanofluid on evacuated U-Tube solar collector efficiency

Abstract

Evacuated U-tube solar collector (EUSC) using Al 2 O 3 /Pure Water (PW) as working fluid was investigated numerically in this research paper. The collector efficiency of the EUSC was analyzed for different operating conditions. Al 2 O 3 nanoparticles suspended in the pure water (PW) with different nanoparticle volume concentrations and shapes were used as collector fluid. Four different nanoparticle volume concentrations (1.0, 2.0, 3.0 and 4.0 vol%) and three different nanoparticle shapes (blade, brick and platelet) were used for formation of nanofluid. Calculations were also performed with three different mass flow rates (0.01, 0.015 and 0.025 kg/s). The effect of volume concentration and shape of nanoparticle on the collector efficiency of a EUSC was analyzed in detail. The highest collector efficiency was obtained at 67.1% for 4.0 vol% Al 2 O 3 /PW nanofluid with bricks nanoparticle shape which is 19.1% higher than PW as the working fluid in the system. • The maximum collector efficiency was obtained as 67.1% at 4.0 vol% and 0.025 kg/s. • The increase in mass flow rate and volume concentration provides efficiency enhancement. • The bricks shaped nanofluids shows the best thermal performance. • Nanoparticle shape effect on collector efficiency was firstly evaluated for EUSC. • Thermo-hydraulic performance is also highest with bricks nanofluids.