Techniques used to maintain minimum water depth of solar stills for water desalination–A comparative review

The necessity for fresh water is critical in everyday life. The most serious issue in underdeveloped countries is a lack of access to clean water, and drinking water from polluted sources to survive can be hazardous to one's health. In many ways, the solar still is a great source of freshwater for both drinking and cultivation, it is one of the most popular essential and technically practicable sun energy uses. Throughout this review, we attempt to study the various techniques used to maintain minimum water depth of solar stills for water desalination. Water depth in solar still has an inverse relationship with productivity of solar still. Investigations suggest that decreasing the depth of the saline water leads to productivity increases due to a rapid increase in the temperature of the saline water and thus the rate of evaporation. Cords, stepped, wicks, absorber shapes and rotating parts were used maintain minimum water depth of solar stills, they can improve distillate productivity. Diverse results (enhancement) demonstrated shown the importance of cords (122%), stepped (30.4–57.3%), wicks (90–154%), absorber shapes (53–69%), and rotating parts (51–300%). The benefit of this review is that it will allow for a systematic understanding of the role and influence of each thermal-method on the daily productivity rate using various minimum water depth techniques. Minimum water depth in solar still research is still being conducted and suggestions for more research projects have been made in light of the study's results.