Maximizing solar distillation efficiency and cost-effectiveness with the rotating ball spherical solar still: An energetic, exergetic, and economic analysis

Abstract

In this study, an innovative solution was introduced by incorporating a rotating spherical ball within the spherical solar still, resulting in the rotating ball spherical solar still (RBSSS), which compared to the conventional spherical solar still (CSSS). The thermal energy, exergy, and economic performances were investigated for both solar stills. The impact of using various rotating speeds (0.5, 1, 1.5, 2, 2.5, and 3 rpm) and using wick material stretched over the rotating ball was studied. The findings revealed that the optimal rotational speed for RBSSS was 1 rpm, resulting in maximal productivity. At this speed, RBSSS exhibited a remarkable increase in productivity (37%) with efficiency of 51% compared to CSSS with efficiency of 33%. When operating at 1 rpm and utilizing wick, RBSSS achieved a 57% increase in productivity. In addition, when operating RBSSS at 1 rpm with wick, the productivity rise, exergy efficiency, and energy efficiency were 57%, 3.73%, and 56%, respectively. The energy efficiency and exergy efficiency of CSSS were stable at 33% and 2.98%, respectively. Finally, the cost of freshwater obtained from RBSSS with wick material was 0.03 $/L. In comparison, CSSS had a cost of 0.05 $/L, and RBSSS without wick had a cost of 0.04 $/L. These findings collectively underscore the potential of RBSSS as a sustainable and cost-efficient solution for potable water production through solar distillation, offering a significant improvement over traditional methods in terms of both productivity and financial viability.