Autonomous Solar-Powered Desalination of Seawater using Low Pressure and Temperature

Abstract

Despite the Earth being composed of 70% water, only a minor fraction of 2.5% is fresh while the remaining is saline, thus being unconsumable. Among the fresh available, only 1% is readily accessible. To tackle this problem, desalination has been recognized as one of the most effective. However, the huge reliance on fossil fuels to operate the desalination plants is not sustainable economically on the long run. Thus, solar energy integrated desalination technologies will provide an alternative which is more sustainable. This project demonstrates the concept of an autonomous small-scale vacuum desalination system which is powered by a solar charged battery using low cost equipment. The system produces fresh consumable water by removing unwanted particles and soluble from the seawater through a process of heating the seawater to a low temperature of 55 ⁰ C. The heated water is then subjected to a low surrounding pressured of -95 kPa (gauge, at sea level) in a Vacuum Tank in which the water boils. The water vapour is then passed through a copper pipe that is exposed to the normal ambient temperature of about 25 ⁰ C, wherein it condenses back into fresh liquid water that flows into a second Tank. Thus desalination has taken place.