Experimental study to improve the performance of solar still desalination by hydrophobic condensation surface using cold plasma technology

Abstract

Improvement of solar still desalination performance has become the agenda of researchers in recent years to be able to make the most of the development of such systems in times of crisis and water scarcity. In the current experimental study, using two solar still desalination systems, the effect of cold plasma coat using Dielectric Barrier Discharge (DBD) on the condensation surface is investigated. To achieve this goal, two still solar systems are tested under the same climatic conditions to demonstrate the effects of the cold plasma coating on the condensation surface wettability and hydrophobicity. Additionally, influence of plasma layer on the internal condensing surface temperature and freshwater production rate is examined. Experimental results show that the contact angle between water droplets and glass cover after using plasma coating will increase, which increases the surface hydrophobicity. Results reveal that the amount of produced fresh water in the uncoated surface desalination system equivalent to 485 ml, while in the system with cold plasma, the maximum productivity with the maximum average solar radiation of 1000 W/m2 and the absorber wall temperature of 70.1 °C, and surface angle of 35° in the experiment day is about 610 mL. Additionally, calculations represent that the produced freshwater using plasma coating increases by 25.7% compared to the uncoated system. The quality of lab-prepared saltwater samples was analyzed before and after desalination, and the results comply with the World Health Organization guidelines for drinking water quality.