Progress and performance of multi-stage solar still-A review

Solar desalination provides a clean and economical way for freshwater supply, thus becoming more and more promising. In this work, the research progress of multi-stage solar still is reviewed, including the stacked tray solar still, the tubular solar still, as well as the vertical diffusion solar still. Both multi-stage stacked tray solar still and tubular solar still have much better performance as compared to single-stage solar still. However, the stage number of the stacked tray and tubular solar still is usually limited to less than 5. On the other hand, vertical diffusion solar stills show the best daily productivity among all three types of solar still, due to more effective stages. Nevertheless, it might incur more problems, such as peeling off of the wick materials, salt crystallization, and so on, which need more investigation in the future. To further improve the multi-stage solar still, it is suggested to introduce more modifications from single-stage solar stills. Besides, new materials specialized for multi-stage solar stills, more attention on passive and low-cost vertical diffusion solar stills, as well as a standard cost analysis method, are also important in the future.

Automated summary

Solar desalination provides a clean and economical way for freshwater supply. This review focuses on the research progress of multi-stage solar stills, including stacked tray, tubular, and vertical diffusion solar stills. Both the stacked tray and tubular solar stills outperform single-stage solar stills, but their stage numbers are usually limited. On the other hand, vertical diffusion solar stills achieve the highest daily productivity due to more effective stages, but they also encounter more challenges that require further investigation in the future.