Thermal performance comparison between Al2O3/oil and SiO2/oil nanofluids in cylindrical cavity receiver based on experimental study

Abstract

Abstract In the current study, the thermal performance of a solar dish concentrator using a cylindrical cavity receiver is experimentally investigated using different working fluids. The examined solar working fluids are two kinds of nanofluids (Al2O3/thermal oil and SiO2/thermal oil) and pure thermal oil. The investigated experimental setup includes the dish concentrator, the cylindrical cavity receiver, heat exchangers and a hydraulic circuit system. The thermal performance of the solar system is compared by application of the examined nanofluids with the pure thermal oil. The results indicated that the average thermal efficiency of the cylindrical cavity receiver using the Al2O3/thermal oil nanofluid has the highest value compared to application of the SiO2/thermal oil nanofluid and pure thermal oil operation in the steady-state period. Moreover, the thermal loss coefficient ( U L ) of the cylindrical cavity receiver using the Al2O3/thermal oil nanofluid has a lower value than the application of the SiO2/thermal oil nanofluid and pure thermal oil. Thus, the application of the Al2O3/thermal oil nanofluid is recommended due to the higher thermal efficiency compared to the other examined working fluids. Finally, three experimental models are suggested for the cylindrical cavity receiver using the Al2O3/thermal oil nanofluid, SiO2/thermal oil nanofluid, and pure thermal oil.