Experimental Performance Analysis of PCM and Fin-Integrated Solar Stills under Varying Water Depths

Limited availability of freshwater has increased the demand of low-cost and sustainable desalination technologies. Basin-type solar stills are a simple and cost-effective solution with a limitation of low thermal efficiency and low daily productivity. To overcome these issues, the current study experimentally analyzes how solar stills can be improved in terms of performance by incorporating phase change materials (PCM) and heat transfer fins. Three designs were constructed and experimented with basin water depths of 2 cm, 3 cm and 4 cm; the conventional solar still (CSS), a PCM-integrated still and a finned PCM-integrated still (FPCM). Thermocouples, pyranometer and graduated collection were systematically instrumented to measure temperature profiles, solar irradiance and yield of distillate. The findings indicate that the FPCM setup was always the most successful, and the daily productivity was about 325 mL/m2/day at 2 cm depth, which is about 40% better than CSS. The PCM-based still yielded intermediate enhancement, with 200-210 mL/m 2/day at 3 cm depth, which is indicative of the correspondence between water mass and PCM charging/discharging performance. CSS had a thermal efficiency of 1.623% versus FPCM of 2.534% and CSS had productive hours of approximately 11 h versus 12 h in FPCM. The peak hourly yield was 50-55 mL/h in FPCM and 38 mL/h in CSS. These results prove that PCM integration improves thermal storage and fins further speed up heat transfer resulting in high-quality distillate yield and long operation. The research confirms that FPCM solar stills is a feasible, inexpensive method of freshwater production in water-deprived areas.