Performance enhancement of stepped solar still via different sand beds, cooling coil and reflectors.

This study aims at enhancing the freshwater from saline water via stepped solar stills (SSS). Experimental work for different sand beds SSS was conducted to enhance its performance, the sand was used as thermal storage materials. The effects of sand type (black and yellow) and sandy bed height on the performance of stepped solar still (SS) were studied. Also, the effect of internal reflectors and cooling coil on the sand stepped SS performance was investigated. Experimental results revealed that the sandy layer improves the stepped SS productions. At 1 cm height of sand beds the accumulated productivity of the conventional solar still (CSS), SSS, yellow SSS and black SSS were 3,000 and 4,650; 5,150 and 5,750 mL/m² ·d, with improvement of 55%, 71%, and 92%, for the SSS, yellow SSS and black SSS higher than CSS. In addition, the maximum increase in accumulated production of sandy stepped SS with internal, external reflectors and cooling coil was obtained at sand beds height of 1 cm and black sand. In this case, the production of black SSS was increased by 165% over CSS with thermal efficiency 56.6%. In addition, in comparison to the CSS, the cooling system increases black SSS productivity by 31%. The environmental parameter of black SSS with vapor withdrawal and reflectors was 24 tons·CO₂ /y. [ABSTRACT FROM AUTHOR]