Modular solar thermal desalination system with flat plate collector

Abstract

This research article shows the experimental results of a solar desalination system to produce potable water for drinking purposes from either sea or salty ground water. This system has two components: a flat plate solar collector, and a desalination tower with heat recovery mechanism. The flat plate solar collector can be used in either direct or indirect heating mode. In the first case, the water that runs through the collector absorber is the condensate produced in the desalination tower. This condensate flows down on sidewall to a clean water tank at the bottom of the tower. The hot water in the tank evaporates and condenses on the walls of the first stage, directly heating the salty water in this stage. In the indirect heating, solar radiation is absorbed in the collector and transferred to a thermal oil flux, which transport this heat to a mass of salty water in the desalination tower. The heat transfer takes place in a heat exchanger at the lowest level, or the first stage in the desalination tower .Two units were built and tested, one for each heating mode. The desalination tower has six stages and a water circulation system through the stages to avoid salt concentration. The results show the good system thermal performance, and that improvements can be made to reach even higher potable water production rates. The water (polluted sea water and salty well water) laboratory test results show that the desalination process eliminated the Coliform group bacteria, being appropriated for human use.