Performance improvement of modified stepped solar distillers using three effective hybrid optimization modifications

The present experimental study concerns to achieves the highest performance improvement of stepped solar distiller by incorporating three effective hybrid modifications on the design; CuO nanoparticles coated absorber surface, interior mirrors, and phase change materials below the steps, with the aims to improve the heat transfer rate, increase the intensity of solar radiation falling on a basin saline water, and increase the operating period several hours after sunset. Two solar distillers were designed, fabricated, and tested in Tanta, Egypt. The experimental results show that the average accumulative yield achieved by modified stepped solar distiller reached 9.79 L/m²/day compared to 4.15 L/m²/day achieve by reference distiller, with an improvement of 135.9%. The average daily thermal efficiency of reference distiller reached 33.3%, while the utilization of modified stepped solar distiller improved the average thermal daily efficiency to 78.8% with an improvement of 136.6%. Also, the average daily exergy efficiency of reference distiller reached 2.77%, while the utilization of modified stepped solar distiller improved the average daily exergy efficiency to 7.96% with an improvement of 187.4%. Based on the above results, the utilization of the effective three hybrid optimization modifications is the good method to achieve the highest performance of stepped solar distiller.