ENHANCED THERMAL PERFORMANCE ANALYSIS OF SINGLE AND DOUBLE SLOPE SOLAR STILLS COATED WITH TiO2 NANOPARTICLE-INFUSED NANOPAINT

With increasing freshwater scarcity worldwide, due to rapid population growth, it is difficult to maintain freshwater supplies; in places like Rajasthan and Gujarat in India, the desalination and purification techniques are proving to be the primary means of meeting the increasing demand for freshwater. However, the growing cost of fossil fuels is making typical distilling practices less competitive compared to other types. Therefore, this study shows that solar stills with TiO2 nanocoating are a cost-effective and sustainable technique for the production of freshwater for regions with water scarcity due to their improved efficiency without the use of conventional energy sources. The experiments were conducted in May and March and included two types of solar stills with a 1 m2 area and water depths of 10 mm, 20 mm, and 30 mm. Each configuration was subjected to three surface coatings of black paint, 2%, and 4% TiO2 nanopaint coatings. The results showed that nanocoating increased thermal efficiency and water yield in single and double-slope solar stills. During March, the single- slope solar still with 4% TiO2 nanocoating attained the maximum yield of 1811 ml/m2 at a water depth of 10 mm, an improvement compared to 1377 ml/m2 with simple paint. The yield for 20 mm and 30 mm water depths also increased significantly with the use of nanocoating. In March, the 4% nanocoated double slope still reached 2488 ml/m 2 at 10 mm of depth, greatly surpassing the 1970 ml/m2 of the simple painted version. Due to elevated ambient temperatures and solar radiation, all stills performed better in comparison to March in the month of May. Double- slope solar stills proved to be more efficient than single-slope stills due to greater condensation surface area and better heat retention. Lower water depths led to higher output, as heating the water required significantly less thermal energy.