Synergistic enhancement of hemispherical solar stills: magnetic field application, vertical Wick integration, and nano-enhanced PCM

Abstract

This study enhances hemispherical solar still (HSS) desalination performance through a modified design (MAHSS) integrating two synergistic innovations: (1) immersion of high-intensity neodymium magnets (270 mT) inside the distiller chamber to intensify evaporation, and (2) coupling with cubic wicking still for spacial efficiency. A subsurface bed of phase change material (PCM + Ag) provided supplementary thermal regulation. Experimental results demonstrated a MAHSS daily output of 6100 mL/m 2 ·day versus 4000 mL/m 2 ·day for conventional HSS, representing a 52.5 % productivity increase. The integrated MAHSS-VCWSS-PCM system achieved 12,400 mL/m 2 ·day (195 % enhancement over HSS), with PCM technology delivering the most significant gain at 65 % thermal efficiency. Economic analysis yielded freshwater production costs of 0.022 USD/L (HSS) versus 0.012 USD/L (MAHSS with integrated enhancements). Environmentally, MAHSS reduced CO₂ emissions by 29.16 tons/year, yielding an enviroeconomic parameter (Z′) of 422.8 USD/year. • Magnetic field-enhanced solar desalination; hemispherical still; neodymium magnets; evaporation efficiency. • Vertical wick solar still integration; spatial efficiency; feedwater preheating; corrugated design. • Ag-nanoparticle PCM; thermal regulation; latent heat storage; solar still productivity. • High-yield solar desalination; 195 % productivity enhancement; 12,400 mL/day output. • Enviroeconomic analysis; solar still CO₂ mitigation; 0.012 $/L water cost; Z′ parameter.