Experimental and modelling investigation on the effect of inserting ceria-based distilled water nanofluid on the thermal performance of parabolic trough collectors at the weather conditions of Amman: A case study

Abstract

This experimental study investigated the performance of two identical parabolic trough collector (PTC) systems using nanofluid CeO2/H2O and distilled water as working fluids under the weather conditions in Amman and various nanofluid concentrations. Two identical manufactured PTC were tested under the mass flow of 0.7 L/min. One of the identical PTC was used in water as a thermal fluid, and the second one was the ceria nanofluid under four diluted volume concentrations, namely, 0.01%, 0.03%, 0.06%, and 0.1%. At the beginning of the tests, the identical PTC were tested using distilled water to ensure that they had approximately the same thermal efficiencies. Results were evaluated under a volume flow rate of 1.2 L/min and the deviation and the average thermal efficiency between them showed low variance, not exceeding 0.4%. Furthermore, during the tests, which were conducted on various days in July 2021 between 10:00 a.m. and 2:00 p.m., both collectors’ direction was tracked using a digital tracking system to guarantee that solar radiation remained perpendicular to the region of the PTC. In addition to the nanofluid preparation and stability checking, the thermal efficiency of the PTC was investigated for various ceria nanofluid concentrations compared with the distilled water. The results showed that the maximum thermal efficiency was obtained for 0.1% volume concentration of CeO2 nanofluid and reached 18.03%, and it reached 17.15%, 16.11% and 14.40% for 0.06%, 0.03% and 0.01% volume concentrations of CeO2 nanofluid, respectively; it reached 11.71% for water. The maximum optical thermal efficiency was enhanced by increasing the concentrations, where the maximum enhancement value of 47.7% was observed using 0.1% volume concentration. Finally, the experimental results for different cases have been compared with the Solidwork simulation, which was developed to obtain the outlet temperature and thermal performance of the PTC. The comparison results showed high accuracy, where the average thermal efficiency did not exceed 2.19%, and the outlet temperature did not exceed 0.10%.