Analysis of non-noble plasmonic enhanced solar distillation using computed optical activities

Solar distillation is an immensely promising, renewable energy-based solution route for potable water production from grey water. Noble plasmonic nanoparticles (e.g., Au, Ag) are typically employed in solar distillation systems for efficiency enhancement. However, their high cost renders such technologies economically nonviable. In this study, we evaluate the prospect of using Cu-coated Al as non-noble plasmonic nanoparticles for solar distillation based on the energy balance across various parts of a solar still (basin, glass cover and fluid). We compute the absorption and scattering cross-sections of these nanoparticles, and hence their optical activity. We show that particles of sizes <60 nm have greater absorption cross-section as compared to scattering cross-section in the ultraviolent (200 to 360 nm) and visible light spectrum (360 to 700 nm). The effects of nanoparticle concentration (0.004 % to 0.024 % of sizes 10–22 nm) in the nanofluid on the yield of distillate, energy efficiency and temperature of the fluid are analyzed. We report that Al-Cu nanoparticles enhance energy efficiency of a conventional solar still by as much as 64 % at a concentration of 0.012 %. The efficiency increases with increasing nanoparticle concentration and begins to saturate after 0.012 % concentration.