Experimental Study of Water‐Based Al2O3 Nanofluid Flow in Direct Absorption Solar Collector

Abstract

SummaryTo overcome the limitations of conventional tube in plate type solar collector such as low collection and conversion efficiency, direct absorption solar collectors using nanofluid as heat transfer media has been proposed. Direct absorption of solar radiation and mixing of nanoparticles in the base liquid improves the optical and thermo physical properties of the base liquids, resulting to an increase in the efficiency of solar collectors. In the present experimental work, the effect of Al2O3–H2O nanofluid, as heat transfer fluid on the efficiency of a direct absorption solar collector was investigated. The ASHRAE standard was used to calculate the instantaneous efficiency. The results show that, in comparison with water as direct solar absorption medium, nanofluid increases the efficiency. For 0.001 vol% the increased efficiency was 12.8%. There is a continuous increase in the efficiency by increasing the volume fraction from 0.001% to 0.01% and beyond that increase in volume fraction values, the solar collector efficiency gets a reverse trend and becomes constant.