Experimental parametrical study of sectioned tilted tubular solar still equipped with hydrogel

Solar distillers are a sustainable and simple solution for addressing water scarcity, but their limited productivity restricts their effectiveness. This work aimed to assess the thermal performance of a novel tracked, tilted, hexagonal tubular solar still (HTSS) of four-sectioned U-channel receiver. Two identical HTSSs were side-to-side tested in Baghdad-Iraq (33.3°N, 43.3°E) from June to September 2024. The thermal evaluation of single-axis tracking solar still, tilted at (5° to 15°) with the horizontal axis and charged with and without hydrogel beads for water depth of 60 mm. The still's thermal performance is assessed by analyzing heat transfer coefficients, energy and exergy efficiencies, as well as conducting cost and environmental impact analyses. A considerable improvement in still yield is achieved as hydrogel is charged in. Results showed that the still thermal efficiency is uplifted by (87.79, 96.24, and 108.26 %) for (2000, 4000, and 6000 beads), respectively, as the tilt angle increases from 5° to 15°. It was found that the present still (with 6000 hydrogel beads, and tilted at 15°) has the best thermal and exergy efficiencies and produces 16.72 l/m², accompanied by 9.91 ton/year emission reduction of CO₂, with a competitive cost for water production of 0.039 $/liter.