Stepped Solar Stills’ Development and Improvement for Seawater Desalination

Document Type : Reviews Articles.


1 Mechanical Engineering Department, Faculty of Engineering, Soth Valley University, Qena, Egypt

2 Department of Chemical Engineering, Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo, Japan


Nowadays freshwater needs were covered by fossil fuel-based desalination systems in many areas over the world. However, fossil fuels’ excessive burning results in rapid depletion and pollution of the local environment as well as threat to life sustainability. Therefore, through the last few decades the scientific community focused on the systems relying on solar energy in seawater desalination as a clean alternative. Stepped solar stills, which convert solar energy to the required heat for producing freshwater in seawater desalination, are paid much attention. This article provides a comprehensive analysis of stepped solar stills’ development. Performance enhancement techniques, desalinated water production, efficiency and maximum theatrical production are discussed. This work aims to keep researchers and concerned scientific community abreast of stepped solar stills’ improvements. Such stills of low construction and running costs can meet the freshwater daily needs for small communities in coastal areas, islands and rural areas especially in Mideast. In conclusion, this review clarified that the stepped type solar stills still need multiple improvements to enhance their production efficiency and freshwater quantity. Further attention should be paid to the design of modified stills to attain better and efficient solar heat absorption as well as evaporation of seawater.


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