Thermo-economic and environmental assessment of modified solar stills with eco-friendly storage-fin composites

Water desalination using solar stills has been widely recognized as an efficient and sustainable strategy to face the increasing reduction of freshwater. The current study compared the performance of three configurations: a still with sand grains in the basin (SS-SG), a still with recycled aluminum cans filled with sand grains (SS-CA&SG), and a still with cans filled with waste engine oil (SS-CA&Oil). The internal heat transfer increased by 32.5 % and 7 % for SS-CA&SG and SS-SG, respectively. The SS-CA&SG had the highest daily productivity of 2.878 l/m 2 , while the SS-SG was 2.538 l/m 2 , and the SS-CA&Oil was 2.138 l/m 2 , with increases in productivity of 23.1 % and 8.46 % compared to the CSS, respectively. The thermal efficiency increased for SS-CA&SG and SS-SG by 23 % and 8.46 %. The SS-CA&SG still had the highest daily efficiency of 7.60 %, a significant increase of 137.5 % compared to the CSS, while the SS-SG was at 5.60 %, with an increase of 75.0 %. The CPL obtained for CSS, SS-SG, SS-CA&SG, and SS-CA&Oil was 0.016, 0.015, 0.013, and 0.018 $/L, respectively. Besides, the payback period was 1.9, 1.7, 1.6, and 2.1 months, respectively, where SS-CA&SG caused the highest reduction in CPL and payback period by 15.54 % and 15.4 %.