Water From The Sea

A greenhouse which uses sunlight to turn salt water into fresh water for growing vegetables or drinking purposes has been developed.

Operating at a fraction of the cost of traditional desalination plants, the greenhouse designed by an English architect is undergoing trials in Tenerife and Oman.

Constructed close to the sea, the steel-framed experimental greenhouse is 5.5 m high by 18 m wide and approximately 48 m long. It can be made larger by linking further modules together.

Made of bended tubular metal embedded in concrete, it is covered with a double-skinned roof that prevents infrared and ultraviolet light from overheating the structure.

The red and blue light spectrums that penetrate into the greenhouse drive the plants' photosynthesis process. With evaporators at each end made from corrugated cardboard, the greenhouse has large surfaces from which seawater can evaporate leaving its salts behind. These strengthen the cardboard giving it a much longer life. Warm air is drawn into the greenhouse and passed through one of two evaporators which are cooled by seawater. Drawn by fans, the humid air saturated with moisture creates good conditions to grow greenhouse crops.

After passing through the growing area, the air arrives at the second evaporator that is also cooled by seawater. The fresh water in the air condenses and is collected for irrigating the crops or stored in a tank and used for drinking purposes.