Experimental Evaluation on the Efficiency of Evacuated Tube Solar Collector Using Al2O3/Deionized Water Nanofluids

Abstract

Most heat transfer devices nowadays are based on the use of nanofluids since these particles are scientifically proven to outperform traditional fluids and are more effective and efficient in thermal transfer. This study considers the deionized water-based Aluminium oxide nanofluid and evaluates its stability. The study also compares the thermal efficiency of evacuated tube solar collector (ETSC) when using Al2O3 /DI nanofluids against the efficiency observed when using base fluid (DI) at different volume fractions in the range of 0.1% - 0.3%. In the next stage, thermal efficiency test was conducted on the solar collector with a range of flow rates including 1.5, 3, and 4 L/min. The use of Al2O3 nanoparticles in the collector during the experiment revealed a maximum rise of 39.6% in the fluid’s temperature difference. These nanoparticles also yielded 33% maximum heat gain when the collector was subjected to 950 W/m2 of solar irradiance. The nanofluids depict a 1.17 to 1.23 greater heat removal factor in comparison to water provided the flow rate is the same for both fluids. The outcomes showed that the use of Al2O3 /DI nanofluid in the ETSC yields 26.3% greater thermal efficiency in comparison to base fluid. Hence, the study suggested better overall performance of the collector in the presence of Al2O3 nanofluid.