Improved performance of vertical solar still by bio-inspired hybrid wettability condenser surface

Abstract

According to recent research conducted by the World Health Organization, approximately 900 million people worldwide suffer from a shortage of fresh water. To address this issue, air gap distillation and multi-effect solar stills have emerged as two promising small-scale desalination techniques that utilize distillation over an air gap. To further investigate the potential benefits of these systems, an experimental study was conducted to evaluate the impact of condenser surface wettability on the performance of a vertical solar still (VSS) with air gap distillation. Specifically, three types of surfaces were tested in the condenser section of the VSS: hydrophilic, hydrophobic, and a hybrid combination of both. The role of the condenser surface was analyzed by examining droplet dynamics, and the results show that the hydrophilic surface outperforms the hydrophobic surface during air gap distillation, producing a higher rate of pure water. Furthermore, inspired by natural patterns found in leaves, a hybrid surface consisting of both hydrophobic and hydrophilic properties was applied to the solar desalination condenser plates. This resulted in a significant increase in pure water production, with a 17 % improvement compared to the hydrophilic surface and a 35 % increase compared to the hydrophobic option. Overall, these findings highlight the potential benefits of using air gap distillation and hybrid condenser surfaces for small-scale desalination applications, which could help to alleviate the global water crisis.

Keywords

• Vertical solar still
• Air gap
• Condenser
• Wettability