Experimental investigation of a passive solar still with and without tetrahedral sponge in basin

Abstract

In this work, an experimental study is carried out to investigate the influence of the presence of porous media on the performance of solar still. Two different shapes of sponge pieces, namely cube and tetrahedron, are considered for this study. Experiments are conducted on a single-slope solar still with condensing cover of 30° inclination. This study was performed in Indian coastal climatic condition for 24 h. The experimental study emphasises on the overall distillate yield, and the efficiency of the still with sponge cubes and tetrahedrons is compared with the conventional still. The size of the pieces is selected such that the volume of both shapes is the same. As the surface area to volume ratio is more for tetrahedral sponge piece, the highest distillate production is observed in that of sponge cube. It is observed that the maximum distillate yield is produced at optimum values of water depth at 5 cm, single piece sponge volume of 216 cm3 and sponge volume of 30% of the basin water volume. The increase in yield is due to the capillary effect and high evaporation rate and it varies from 45% to 219% with tetrahedral sponge pieces when compared to conventional still.