Water Desalination by Solar Energy

Abstract

One of the basic requirements for all living things in this world is the availability of pure drinking water. Nowadays, the world is facing a huge water crisis, and clean water sources are being contaminated by man-made pollution and overexploitation. Water demand will grow in the future with population growth and increased urbanisation and industrialisation. Desalination is one of the oldest technologies used for water purification. Conventional desalination techniques utilise electric power, which is not economic, and also it has an indirect adverse effect on the environment due to the pollutants generated during power plant operations. Even today, underdeveloped countries and developing countries face a huge water scarcity because of unplanned mechanism and pollution created by man-made activities. Water desalination without affecting the ecosystem is the need of the hour. Water purification using solar energy has become more popular because of its eco-friendly nature and low cost. A solar still is a commonly used device for water purification, and it does not require any electricity for its functioning and it is the most suitable device for the urban and rural areas. The solar still is mainly classified into two groups, namely, the passive solar still and active solar still. The passive solar still is simple in design, low cost, low maintenance, but the yield is very low. Active solar still consists of additional components to supply the thermal energy and therefore, the yield is high. In the last three decades, many new passive and active solar stills are developed all over world, and research works are still going on to improve the system performance and other aspects of solar stills. Looking into its importance in the present and future, this chapter creates a comprehensive knowledge and research advances in various designs of solar still. This chapter also covers the principle of solar distillation and advantages of solar stills in crunchy manner.