Comparative performance investigation of conventional and modified stepped basin pyramid solar still with improved insulation: Experimental evaluation

This study focuses on modifying the insulation of a stepped basin pyramid solar still (SBPSS). The modified SBPSS with both side insulation and the conventional SBPSS with one side insulation of the base were compared in terms of basin and basin water temperature, freshwater output, energy and exergy efficiency, payback period, and production cost. The research was carried out on two identical SBPSSs, where 0.25 m2 was the evaporation area for each case. In modified SBPSS, the insulation on both sides of the base significantly reduced heat loss, which was justified by the higher basin and basin water temperatures than conventional SBPSS. The maximum basin temperatures for conventional and modified SBPSSs were 50.49 degrees C and 53.74 degrees C, respectively, with maximum basin water temperatures of 47.21 degrees C and 52.86 degrees C. The modified SBPSS provided more freshwater (1.24 L/m2) than conventional SBPSS (0.93 L/m2) as a result of the rapid evaporation rate caused by the higher basin water temperature. For conventional and modified SBPSSs, the average energy efficiency was 22.33 % and 27.51 %, respectively, and the average exergy efficiency was 4.71 % and 6.90 %, respectively. The modified SBPSS provided freshwater at a 24.27 % lower price than the conventional SBPSS.