Experimental Simulation of Solar Flash Desalination

Abstract

Experimental simulations of a sustainable desalination process have been carried out using a pilot unit. Experiments were conducted at analogous conditions to simplify design evaluation but with different values of the controlling variables to enhance analysis and modeling. The proposed desalination process, which employs solar heating and passive vacuum generation, has been theoretically simulated in earlier work. It entails flowing seawater through a condenser to preheat it and then through a heater before flashing it in a vacuumed evaporator connected to the condenser where the flashed hot vapor is condensed by the incoming cold seawater forming fresh water. All experiments were run for the same period of time starting at the same initial vacuum. Experiments were carried out at different seawater flow rates and different flash temperatures. In addition, each experiment was duplicated three times to validate its outcome. Flashing seawater at higher temperatures increases vaporization and fresh water production rate. In addition, the accumulating noncondensable gases that are slowly eroding the vacuum will decrease the overall vaporization with time, which reduces the production rate of fresh water.