Performance analysis of a contactless nanostructure in solar-powered desalination system.

Abstract

To address the water scarcity problem, solar desalination by using solar still can be one feasible solution to purify the water. Researchers recently developed thermal absorption materials fully and partially submerged in water and floating. These thermal absorption materials transfer their absorbed solar energy to water through thermal conduction. However, direct contact of these thermal absorption materials with water will damage the material, reducing life. Here we developed a novel contactless nanostructure that is not in contact with water. The contactless nanostructure will first absorb the solar energy and then re-radiate the absorbed energy to water, resulting in water heating, evaporation, and condensation. Experimental results showed that the use of a vertical mirror of size 75 × 50 × 0.5cm could able to enhance the productivity by 79.7% when synthetic saline water (3.5% Wt. NaCl) with 1-cm water depth was used inside the contactless nanostructure solar still (CNSSS) compared to without mirror. The salt deposition is completely prevented owing to the physical de-coupling of the nanostructure from water, resulting in a long lifespan of the nanostructure that can be used for years.