An experimental investigation on the effect of Al2O3–H2O nanofluid on the efficiency of flat-plate solar collectors

In the present work the effect of Al2O3–water nanofluid, as working fluid, on the efficiency of a flat-plate solar collector was investigated experimentally. The weight fraction of nanoparticles was 0.2% and 0.4% and the particles dimension was 15 nm. Experiments were performed with and without Triton X-100 as surfactant. The mass flow rate of nanofluid varied from 1 to 3 Lit/min. The ASHRAE standard was used to calculate the efficiency. The results show that, in comparison with water as absorption medium using the nanofluids as working fluid increase the efficiency. For 0.2 wt% the increased efficiency was 28.3%. From the results it can be concluded that the surfactant causes an enhancement in heat transfer.

► The efficiency of solar collector is increased up to 28% by using the Al2O3 nanofluid.
► The efficiency at 0.2 wt% for wide range of (Ti − Ta)/GT is higher than that at 0.4 wt%.
► The efficiency for 0.4 wt% at higher (Ti − Ta)/GT is better than that for 0.2 wt%.
► By using the surfactant, the maximum enhanced efficiency is 15.63%.
► The efficiency of solar collector increases with increasing the mass flow rate.