Experimental study of mono and hybrid nanofluids on square pyramid solar still

The lower productivity of square pyramid solar still is the prime impediment to its worldwide applicability. In the present study, efforts have been made to improve the productivity of square pyramid solar still using mono and hybrid nanofluid. The experiments were carried out with two similar square pyramid solar stills at a 1cm depth of basin fluid (saline water, mono, and hybrid nanofluid) under the climate of location (20.61°N 72.91°E). Copper (Cu) and aluminum oxide (Al₂O₃) nanoparticles were chosen to prepare mono and hybrid nanofluid. The 0.1% weight concentration of mono and hybrid nanofluid was prepared for experimentation. The hybrid nanofluid was prepared for the different mixing proportions of Al₂O₃-Cu such as 80:20, 60:40, 50:50, 40:60, and 20:80. For the case of use of mono-nanofluid, the performance of square pyramid solar still with Cu nanofluid was higher than Al₂O₃ nanofluid. The total productivity of 1640 mL/m² and diurnal average efficiency of 17.00% were achieved for square pyramid solar still with Cu mono-nanofluid than saline water. A higher distillate yield was achieved for the square pyramid solar still with hybrid nanofluid than the mono-nanofluid and saline water. The diurnal average efficiency of 34.50% and maximum distillate output of 2644 mL/m² were obtained for the square pyramid solar still with Al₂O₃-Cu hybrid nanofluid for the mixing ratio of 20:80. The efficiency and distillate output were higher by 27.41% and 25.19% for the square pyramid solar still with Al₂O₃-Cu (20:80) hybrid nanofluid than the square pyramid solar still with saline water. The distillate yield decreases with a decrease in the proportion of Cu nanoparticles.