Synergistic thermal enhancement in hybrid solar desalination: A vertical wick-spherical still integration with nano-enhanced PCM

The global freshwater scarcity crisis necessitates the development of high efficient and scalable solar desalination technologies. This study introduces a novel hybrid system that synergistically integrates a spherical still (SPSS) with a vertical corrugated wick solar still (VCWSS) to enhance productivity through thermal recycling and advanced energy storage. The system employs a closed-loop feed mechanism where the VCWSS preheats feedwater, elevating the operating temperature of the SPSS. Key innovations include a corrugated wick to maximize evaporation surface area and nano-enhanced phase change material (PCM) with silver nanoparticles and metallic fins to overcome low thermal conductivity and store thermal energy for nighttime distillation. The results demonstrate transformative improvements: the modified spherical still (MSPSS) with nano-PCM and fins achieved a 65 % productivity increase (6950 vs. 4200 mL/m2/day) over a conventional SPSS. The hybrid MSPSS-PCM-Ag-Fins + VCWSS configuration yielded a peak output of 13,000 mL/m2/day, a 199 % enhancement. Thermal efficiency was progressively elevated from 49.7 % to 64.85 % through these integrations. This work successfully resolves critical scalability-efficiency trade-offs, presenting a high-yield solution for sustainable solar desalination.