The use of solar energy as an economical source for realising large scale industrial sea water desalination is still unattainable. One of the main obstacles in this respect is the need for expensive solar collectors to cover large areas for collecting solar energy. For an economical solar desalination plant, not only the used process has to be efficient and cost-effective, but also the costs for collecting of solar energy have to be minimized. Both issues are the subject of the present project in order to approach an economical solar desalination of sea water.

A new sea water desalination process and the adequate solar collectors will be developed within the actual R&D project being partly supported by the European Commission.

By the proposed process, substantial investment reduction will be realised using air as a heat carrier and keeping the maximum operating temperature in the desalination plant significantly below 100 °C. The moderate solar heated air will be humidified by injecting sea water into the air stream. Later on, the water being free of salt will be extracted from the humid air by cooling it.

A main feature of the present process is the successive loading of air with vapour up to a relative high humidity, such as 15 or 20 weight per cent. Such a high concentration of vapour is usually attainable by spraying water in hot air at about 500°C. The present process achieves the same effect at a maximum operating temperature not exceeding 80°C.

Aside from the optimized new process, a major subject of investigation is the design of new cost-effective plant components, especially the collectors. The development of new designs of economic collectors is already concluded providing a high efficient collector at low cost as required for the actual desalination process.

The developed desalination process and the new collector types will be the basis to design a pilot plant going to be constructed on the Mediterranian coast of North Africa where the complete process and the newly developed plant components can be tested and optimized.