Scrutinization of Coated Solar Collector Efficiency with Nanoparticles

This study analyzes the effects of nanofluids on the efficiency of a coated indirect solar collector under various operating conditions. The irradiance level improved the efficiency of the coated solar collector by approximately 1-3% using a water-based aluminum nanofluid for the same nanoparticle size and volume fraction. The solar collector efficiency was significantly affected by the irradiance level, as opposed to the small impact of the nanoparticle percentages. Moreover, a higher irradiance level increases the energy of the nanoparticles and enhances their impact. The impact of the nanofluid mass flow rate was also investigated and evaluated by varying the volume fraction of the nanoparticles. The improvement was promising, at approximately 3%. Because of the superior thermal conductivity, heat capacity, and fluid field provided by the nanoparticles, solar collectors are more efficient. The study also evaluated the impact of varying the nanoparticle types using $\mathrm{A}1_{2}\mathrm{O}_{3}, \mathrm{Z}\mathrm{n}\mathrm{O}$, and $\mathrm{T}\mathrm{i}\mathrm{O}_{2}$ at the same mass flow rate, irradiance level, and volume fraction. The solar collector efficiency values changed slightly owing to the change in the nanoparticle type for the same concentration and mass flow rate. The results showed similar efficiencies for all types of nanoparticles. Owing to the thermophysical properties and particle size of $\mathrm{T}\mathrm{i}\mathrm{O}_{2}$, the solar collector efficiency was slightly higher than that of $\mathrm{Z}\mathrm{n}\mathrm{O}$ and $\mathrm{A}1_{2}\mathrm{O}_{3}$ in this case.