A Revolutionary Seawater Greenhouse Offers Hope in the Desert
by Nick Nuttal, Environmental Correspondent, The Times, UK
PEOPLE living in the world’s arid regions could enjoy fresh water courtesy of a British architect and his revolutionary seawater greenhouse.
The pioneering building, which won an architectural award at the Design Museum last night, uses sunlight to turn salt water into fresh water for growing vegetables and for drinking water.
Increasing areas of the globe are becoming “water-stressed”, according to a United Nations report published last month, and there are fears that areas in Africa, the Middle East and Asia are running dangerously short.
The ingenious building, designed by Charlie Paton, 49, operates at a fraction of the cost of traditional desalination plants, costing 21p to make 1,000 litres of distilled water.
The first seawater greenhouse has been built on Tenerife, partly with European Commission funds. A second is under development in Oman and there are plans for others.
At the heart of the design is a steel-framed greenhouse with “evaporators” at each end made from corrugated cardboard. This creates a huge surface area, allowing fresh water to evaporate, leaving salts behind. These strengthen the cardboard, so that it will last indefinitely.
The roof lets in light in the red and blue spectrums, which is needed for photosynthesis. Infra-red and ultraviolet are used to heat air in a roof cavity to help to drive the evaporation processes.
Mr Paton, whose Light Works company is based in Hackney, East London, said that in hot countries the crops would wilt and die if the greenhouse becomes too warm. The first evaporation unit not only produces humid air, but helps to cool it, too, to create optimum growing conditions.
After the air has blown through the building, it arrives at a second cardboard evaporation unit, which is close to cold salt water being pumped by. The fresh water in the air condenses out and is collected for irrigating the crops.
Dr Chicarelli-Robinson said that eight of the the 20 bestselling drugs in the world, representing sales of £7 billion a year, were derived directly from plants. At least 50 per cent of the top 100 drugs are derived directly or indirectly from plants, she said.
These include aspirin, originally from willow, morphine from poppies, atropine from deadly nightshade for treating asthma, and Diosgenin, a contraceptive from the Mexican wild yam. It is claimed that oats are useful against colds, depression, muscular sclerosis and shingles, and the researchers hope to isolate the chemicals concerned.
Dr Chicarelli-Robinson said the work could help hard pressed farmers by offering new cash crops.