Low cost model for desalination of water using solar energy to overcome water scarcity in India

Abstract

Day after day, the need for potable water rises and the amount of potable water available decreases at the same time. Around 97 percent of all the water on Earth is saline water in the oceans and aquifers. There is only 2.5–2.75 percent of fresh water available, including 1.75–2 percent frozen ice glacier, 0.5–0.75 percent fresh groundwater and less than 0.01 percent surface water in lakes, swamps and rivers. Fresh water is renewable and variable; it is a restricted commodity, however. Only by the water cycle, in which water from seas, streams, soil, rivers and reservoirs evaporates, creates clouds and returns as precipitation, can fresh water be replenished. 0.003 per cent of absolute water is fresh and unpolluted water. In India many villages and communities still rely on river water for drinking purposes but the water available in river is majorly polluted due to human activities. The ocean water which is available in huge quantity comes to rescue in this scenario. The saline water of ocean can be converted into drinkable water using solar energy in an affordable manner. This paper describes a unit which is designed on simple principles of evaporation and condensation with no electricity being used. Thus we harness the heat radiated by the sun to accomplish the evaporation segment. The water will be condensed by natural temperature difference between heated and non-heated segment. The unique aspect of this paper is the use of convex lenses to heat the water initially from the tank such that the water being heated by the sheet evaporates at an increased rate due to the incoming water having an elevated temperature.