ASSESSING THE SOLAR-GROUND STILL PERFORMANCE FOR DIFFERENT DEPTHS OF SALINE WATER: AN EXPERIMENTAL STUDY

In this study, experiments are carried out on a single slope single basin passive solar-ground still, which exploits ground heat for the continuation of the fresh water production during late evening hours, for different depths of the saline water. An attempt has been made to utilize the maximum amount of solar energy and to alleviate the heat losses from the bottom and side surfaces of the still. The fabricated Solar-Ground still possesses no bottom insulation and its side surfaces are covered by sand. As the ground layer in contact with the still, functions both as sensible heat storage medium and insulation film, the excess heat energy is absorbed during noon hours is released back to the basin during late evening hours. This causes the temperature difference between the basin water and glass surfaces increases and thus boosts the evaporation rate. The daily productivity observed for the 20mm, 30mm, 40mm water depths is 2.01 kg/m2, 2.45 kg/m2 and 2.19 kg/m2 respectively. To show the effectiveness of the modification, solar-ground still performance is compared with traditional still for 30 mm water depth, under the same climatic conditions and 17% increment in daily productivity is observed.