Investigating the performance of dish solar distiller with phase change material mixed with Al2O3 nanoparticles under different water depths.

Abstract

The problem of potable water shortage all over the world made the scientists seek for solutions to overcome this problem. Solar distiller is one of the introduced solutions, but it demerited by the low freshwater output. In this proposed paper, a design modification includes the use of a convex dish absorber instead of the flat absorber liner. The modified solar distiller is nominated by dish solar distiller. The base of dish solar distiller was circular. In addition, a cotton wick was used as a wetting material for facilitating the evaporation process inside the distiller. Besides, the effect of different water heights in the clearance around the dish dome was investigated for 1, 3, 5, 7, 9, and 12cm. Finally, the space under the dish absorber is filled with a phase change material of paraffin wax mixed with aluminum oxide nanoparticles. Experimental results revealed that the best dish height that provided the highest freshwater productivity was 9cm, where the average daily yields of dish solar distiller (at 9cm) and conventional distillers were reported as 4500 and 3000mL/m2.day, respectively. Then, the productivity of dish solar distiller was improved by around 50% over that of the conventional distiller. In addition, when using the phase change material, the average daily distillate of dish solar distiller was improved by approximately 95% compared to that of the conventional solar still, where the distillate of conventional still and dish solar distiller with phase change material at 9cm water depth was 3580 and 6980mL/m2.day, respectively. Besides, the maximum thermal efficiency of dish solar distiller was obtained when using phase change material at 9cm water depth, where it was 62.4% compared to 30% for the conventional distiller.