Effect of various factors and diverse approaches to enhance the performance of solar stills: a comprehensive review

The need for fresh drinking water is increasing rapidly, and drinking water availability reduces day by day. Solar desalination is a viable option to change saltwater to fresh drinkable water. Solar still used for desalination includes processes like heating, evaporation, and condensation. The major problem faced by solar stills is that they have low productivity. Therefore, high demand for freshwater cannot be met. The present review aims to provide the researchers with an idea to select suitable methods for enhancing solar stills' performance. This article mainly focuses on the climatic, design, and operational parameters affecting the performance of solar stills. Results reveal that a combination of the incredible intensity of solar radiations, solar still type, and regions with optimum temperature can provide higher daily distillate output. Further, high productivity can be achieved with inclined solar stills by making an inclination angle equivalent to the location's latitude. A water depth of around 1 cm can provide the best output in terms of productivity for conventional solar stills. A combination of V-corrugated absorber plate with fins and energy storing materials coupled with external reflector plates can provide optimized conditions to enhance productivity. The performance of solar still can be improved by minimizing the gap between absorber plates and condensing cover. Finally, the sun tracking system, either single or dual axis in solar still, can enhance productivity.