Seawater distillation through solar evaporation

Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, Cape Town, 2007An investigation was performed into a new desalination plant operating on the principles of distillation through the utilisation of solar energy only. The need for such a system is due to the high energy requirements of current large scale desalination systems and that, in the future, more and more desalinated water will be required to sustain life in certain areas. A conceptual design of such a plant was completed and it proved its feasibility by providing an in depth explanation of the principles that govern its operation. A computer model, in the form of a MathCAD program, was developed to simulating this process flow. The accuracy of the program was investigated with the help of a pilot plant. It is shown that such a full scale plant would produce, in the region of Saldanha Bay, a town on the Western Coast of South Africa, 5000m3 ofpotable water a day with a solar absorption/evaporation area of 1,87knlrequiring only 1,75kWh per cubic meter of water produced. Its electrical energy requirements can be provided using solar panels allowing the plant to remain independent of external electrical supplies. This electrical energy requirement is less than 33% of the least energy intensive alternative method, reverse osmosis. Since the production rate is dependent on the absorption/evaporation area the plant can be scaled to fit the specific production rate required