Investigating the economic, energetic and exergetic aspects of semi-cylindrical solar still integrated with stepped-basins and phase change material

This study aims at improving the thermal analysis of a semi-cylindrical, stepped-basins solar still (SCSBSS) that incorporated with (PCM-Paraffin-wax) phase change material. The SCSBSS was evaluated and compared with the semi-cylindrical solar still (SCSS) as a conventional one under various water depths for Egyptian climate conditions for different salt water quantities. Furthermore, the economic analysis, energy and exergy efficiencies for various modifications were discussed. The results show that the best performance belongs to the SCSBSS with PCM which produced 3889 mL/m2.day with an increase of the daily productivity of 44.52 % compared with SCSS without using PCM at salt water quantity of 20 L. The CPL of potable water and payback period for a SCSBSS with PCM were approximately 0.0157US$/L and 123 days with a considered lifespan of 10 years at salt water quantity of 20 L. In addition, the results indicated that the thermal and exergy efficiencies of SCSBSS with PCM were 36.86 % and 3.27 % respectively.