4E performance assessment of innovative tubular solar still enhanced with evacuated tube heater, thin-film hanging wick, and cover cooling

This study explores the potential performance improvements of a tubular solar still (TSS) through innovative design modifications. Three configurations are explored a hanging wick for thin-film evaporation, an evacuated tube solar heater to boost evaporation, and a cover cooling system to enhance condensation. In the first setup, the TSS achieved a daily output of 4.57 L/m², which represents a 38.48 % increase compared to the conventional solar still (CSS) average output of 3.2 L/m². The energy and exergy efficiencies increased to 43.92 % and 3.72 %, respectively, compared to the CSS, which achieved 33 % and 2.1 % for energy and exergy efficiencies, respectively. In the second configuration, the TSS showed further improvement with a daily yield of 8.32 L/m², an increase of 157.5 % over the CSS. In the third configuration (the best case), the daily yield increased from 3.2 L/m² in the CSS to 9.96 L/m², an improvement of 205.48 %. Energy and exergy efficiencies increased to 88.29 % and 9.42 %, respectively. The third configuration has the minimum cost of producing water was 0.0170 $/L alongside 412.79 % enhancement in exergy output (220.43 kWh/year) over the CSS, and five times CO₂ emission reduction (5.29 tons).