Numerical assessment of an optimized solar still integrating PCM, nanoparticles, and metal foam with reflector-based optical enhancement

This work delivers a detailed computational investigation of a novel single-slope solar still enhanced through the integration of several performance-improving techniques, including phase change material (PCM), copper oxide (CuO) nanoparticles, copper metal foam, and externally positioned optical reflectors. Six different system configurations were designed and simulated in ANSYS FLUENT using species mixture approach. The thermophysical characteristics of the PCM and the spatial distribution of reflector-induced heat flux were implemented through user-defined functions (UDFs). Optical analysis of the reflector system was conducted using SolTrace and the reflector angles were optimized. This optimization determined that the best left and right reflector inclinations are 62.74° and 71.25°, respectively, to achieve maximum solar energy concentration on the basin surface. The numerical framework was validated against two distinct experimental datasets. The findings indicate that utilizing reflectors and nanoparticles enhances the PCM liquid fraction by 19.52% and 16.09%, respectively. The addition of tree-shaped fins, metal foam, and nanoparticles significantly accelerates PCM melting, reducing the complete melting duration to 6220 s, and further down to 5250s when reflectors are employed. Freshwater productivity is found to be most sensitive to optical enhancement; integrating reflectors raises water yield by 54.85% compared to the baseline configuration, achieving 0.095 kg/m2 in the PCM + reflector setup—nearly seven times higher than that of the nanoparticle–metal foam case without reflectors.