'Seawater is taken from a saline groundwater well. It's better to do that than use a pipe from the sea because this way it's already filtered and comes up very clean,' explained Paton.
The relatively cool air is then drawn through the greenhouse by fans. The company says that as the air leaves the growing area, it passes through the second evaporator over which seawater is flowing. This seawater has been heated by the sun in a network of pipes above the growing area, making the air hotter and more humid. It then meets vertical pipes containing cool seawater. When the hot humid air meets the cool surfaces, fresh water condenses as water droplets that run down to the base where they can be collected.
Paton, who has trialled units in Tenerife, Abu Dhabi, Oman and Australia, said up to one tonne of water can be generated per day through this process, which can be used to irrigate the crops. Excess water can be used on crops outside the greenhouse.
He added that Seawater Greenhouse can cut water consumption in greenhouses in arid regions by 75-90 per cent.
According to the UN, 1.2 billion people, or almost one-fifth of the world's population live in areas where water is scarce and there are an additional 500 million people approaching this situation.