Effect of nano-coated CuO absorbers with PVA sponges in solar water desalting system

Abstract

Nanostructured Copper Oxide (CuO) is coated on the stainless steel (SS) 316 substrates using thermal evaporation method. The effect of CuO nanostructured coated absorber plates (NCAP) integrated with Polyvinyl Alcohol (PVA) sponges is investigated in a single slope solar still (SSSS) for desalination. The experiment was conducted in the following configurations: (1) SSSS alone, (2) SSSS with CuO-NCAP, (3) SSSS with PVA sponges and (4) SSSS-CuO-NCAP with PVA sponges. Four identical SSSSs were built with 0.50 m2 collector area and tested under the same climatic conditions of Chennai, India during the period of March to April 2018. The CuO coated on the SS316 was characterized by Grazing Incidence X-ray Diffraction (GIXRD), Field emission Scanning Electron Microscope (FESEM) and Energy Dispersive Spectrum (EDS). The climatic parameters like ambient temperature, solar radiation and internal temperatures of the SSSS were measured at frequent intervals of time. The efficiencies of the SSSS, SSSS-CuO-NCAP, SSSS-PVA sponges and SSSS with CuO-NCAP-PVA sponges are 37%, 53%, 32% and 41% respectively. The productivity of SSSS, SSSS-CuO-NCAP, SSSS-PVA sponges and SSSS with CuO-NCAP-PVA sponges are 2144 ml/m2/day, 2995 ml/m2/day, 1970 ml/m2/day, and 2318 ml/m2/day, respectively. Therefore, the addition of the sponges was counterproductive, but the CuO-NCAP significantly increased output.