Desalination is a convenient process to develope a fresh water supply in coastal areas. Reverse osmosis and conventional thermal distillation can be used for implementing the large-scale seawater desalination. Desalination is the process in which fresh water is formed from seawater or brackish water by removing dissolved salt, to make it suitable for human consumption. A high yield of disposable water is manufactured by the desalination process. Desalination permits a widening in the utilization of existing water sources by manufacturing freshwater from briny water sources. Fig. 1 shows the process for the desalination system. Over the past era, in many parts of the world, conventional water production costs have been rising and costs for desalination have been abating, subsequently desalination has turned out to be all the more financially appealing and competitive [1,2].The lack of water is usually depicted in volumetric or absolute terms. The most scarcity studies focus on how the 'problem' of scarcity is raised, therefore to overcome this issue the first step is heating of an air stream by using solar energy for heating of an air stream and in the next step to seawater adding into the hot air in imperative to moisten, then final step is a humid air cooling providing potable water as a condensate. The conventional technique for seawater desalination is to vapourize salty water and afterward condense the rising vapour being free of salt. Using fossil fuels as an energy source, these desalination plants are planned as multi-stage evaporator plants. This technique is the foundation for a day-to-day production of million cubic meters of water. This review is focused on the performance analysis of different techniques such as multistage flash distillation, multi-effect distillation, vapour-compression distillation, solar humidification, electrodialysis reversal, reverse osmosis, nanofiltration, forward osmosis, solar desalination for separation of brackish water. Based on literature discussion with their remarks from different techniques, solar desalination has achieved 87 % of efficiency and lower the total dissolved solids content as 40 ppm. Moreover, cost of distilled water per liter $ 0.029 from solar desalination plant. With this advantages, solar desalination has more attractive technique while compare to other towards better future and balanced eco-system.

Solar energy is one of the most common and eco-friendly non-conventional types of energy source which is having various applications like purification of saline water. The experimental study of the present research work has been performed at the M.A.N.I.T, Bhopal M.P, India (latitude: 23°12′ 51″ N, longitude: 77° 25′ 0″ E) in the month of January 2018. The investigation has been performed on single slope solar still coupled with a flat plate solar collector to examine the thermal behaviour of the solar system and results have been presented in natural and forced convection mode. The overall efficiency reached up to 9.86% in natural mode where as 16.70% in forced mode. Therefore, forced mode solar still option is better and preferred.

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