| Abstract: | In this work, an attempt has been made to enhance the distillate output of a single-basin solar still by coupling it with a flat plate solar collector and by coating a thin layer of SnO2 on one side of the transparent cover plate. The heat transfer fluid was circulated between the still and the collector through a heat exchanger and storage tank by thermosyphonically induced flow. It was observed that good insulation around the storage tank considerably increased the yield at night due to the decrease of ambient temperature. Thermosyphonically induced flow eliminated the need for pumps and control units. A layer of SnO2 on the transparent cover lowered the thermal radiation loss, one of the major sources of heat energy loss in a solar still. Values for solar radiation, ambient air temperature, salt-water temperature in the basin, temperature of air-vapour mixture within the still, input and output temperatures of the heat exchanger heat transfer fluid, and the distillate yield were collected by a data acquisition system. After making the above modifications, the distillate yield was measured to be 6·745 litres per square metre per day for a September solar radiation of 17820 KJ at Istanbul-Gebze. To compare the distillate yield, a conventional solar still with similar dimensions to those of the improved still was constructed. The overall efficiency of the improved still was found to be 3·26 times the efficiency of the conventional still. |
