Optimization configuration of cylinder-shaped magnets for augmenting the performance of conical stills

Most countries face increasing challenges in providing drinkable water due to the scarcity of water resources and the high costs of conventional desalination technologies that rely on fossil fuels. Solar stills are considered one of the most important sustainable and low-cost solutions; however, their limited productivity and efficiency restrict large-scale deployment. In this study, a traditional conical solar still (TCSS) was enhanced by incorporating low-cost cylindrical magnets (CSS-CSM&1, CSS-CSM&3, CSS-CSM&5, and CSS-CSM&7) to modify water molecule behavior and improve heat transfer. The systems were evaluated through comprehensive 6E analysis along with two sustainability indicators. The results showed that water productivity increased by 23.3 %, 41.9 %, 64.5 %, and 85.8 % for CSS-CSM&1, CSS-CSM&3, CSS-CSM&5, and CSS-CSM&7, respectively, compared to the TCSS. Thermal efficiency improved from 35.5 % in the TCSS to 45.5 %, 52.0 %, 60.3 %, and 67.9 %, corresponding to relative increases of 28.4 %, 46.5 %, 70.1 %, and 91.5 %. Exergy efficiency rose by 41.8 %, 104.4 %, 176.8 %, and 249.1 %, respectively. The cost of production (CPL) decreased by 12.4 %, 18.3 %, 24.6 %, and 28.9 %, while the payback period was shortened from 76 days (TCSS) to 66, 62, 57, and 54 days. Environmentally, net lifetime CO₂ mitigation increased from 18.8 tons (TCSS) to 24.2, 27.8, 32.1, and 36.1 tons for the modified solar stills, resulting in carbon credit returns of 273.13 $, 351.33 $, 402.66$, 464.94$, and 523.42$, respectively. Furthermore, the Sustainability Index (SI) improved from 1.02 (TCSS) to 1.06 (CSS-CSM&7), while the Improvement Potential (IP) decreased from 2050.23 to 1893.12.