Solar Stills for Desalination of Water in Rural Households

Direct sunlight has been utilized long back for desalination of water. Solar distillation plants are used forsupplying desalinated water to small communities nearby coastal remote areas. Solar stills are easy toconstruct, can be done by local people from locally available materials, simple in operation by unskilledpersonnel, no hard maintenance requirements and almost no operation cost. But they have thedisadvantages of high initial cost, large land requirement for installation and have output dependent on theavailable solar radiation. If there is no sunshine, the productivity is almost zero for conventional basintype model. However, from the simplest basin type models of solar still in earlier days, researchers haveprogressed a lot to increase its efficiency. Suitable modification of solar still can produce high outputusing minimum areas of land and even in cloudy days. One of such upgraded version is capillary stills,which are gaining popularity for their high output. The heart of capillary still is a fabric (woven or nonwoven)which facilitates rapid evaporation of water at minimum heating. An overview of solar stills andcapillary solar stills are discussed in this article.