Effect of cost-free energy storage material and saline water depth on the performance of square pyramid solar still: a mathematical and experimental study

Low productivity of single-slope solar still is the main barrier for its worldwide usability. An attempt has been conducted to enhance the distillate yield of single basin square pyramid solar still using thermal storage material in basin. The experiments were conducted with two identical single basin square pyramid solar stills under the climate of location (20.61 degrees N 72.91 degrees E), one with small pieces of black granite as a thermal storage material and other without black granite. With and without thermal storage, the effect of saline water depth (30 and 20 mm) was investigated on the performance of still. Compared to still without thermal storage, yield of 1430.40 mL m(-2) (13.96% higher) and 1380.40 mL m(-2) (6.63% higher) was obtained at water depth of 30 mm and 20 mm for the still with thermal storage. The daily average efficiency of 18.69% (11.35% higher) and 18.58% (5.09% higher) was obtained at water depth of 30 mm and 20 mm for the still with thermal storage. The higher yield was achieved at water depth of 30 mm than the 20 mm for the still with thermal storage, whereas the higher yield was achieved at water depth of 20 mm than the 30 mm for the still without thermal storage. Transient model for the still with and without thermal storage was developed, and the results were compared with experimental outcomes and good agreement was observed.