A comprehensive review of direct solar desalination techniques and its advancements

Abstract

Demand of fresh water is rising continuously because of increase in population. This has created an undue burden on limited reserves of fresh water. Desalination is one of the methods which works on the principle of natural evaporation and condensation and can be used to treat ocean water into fresh water. One of the sustainable ways of converting saline water into fresh water is through the use of direct solar desalination technology. This review article analyses active solar still and passive solar still and its advancements in terms of productivity and efficiency to produce fresh water. This paper depicts a detailed comparative analysis of various direct solar desalination processes in terms of various performance parameters. Modifications and innovations in the design of solar still were discussed in detail, resulting in maximizing the productivity and efficiency, reduction in capital cost and easy in installation. Advancement in solar desalination technique through the use of Phase change material (PCM) and novel nanocrystals to make solar stills more productive and efficient was discussed in detail. Additionally, a detailed comparison of modified solar still on the basis of various performance parameters like location, water temperature, daily solar radiation level, daily yield, angle of tilt, productivity and efficiency was presented. Effect of using reflectors, concentrators and modified absorber area on various performance parameters of solar still was also investigated. Authors also presented a brief economic analysis of various desalination methods in terms of cost of water ($)/L. At last, authors presented some recommendations based on this review for future work on solar water desalination process.