Vertical farming with seawater
March 24, 2009 The saying used to go, ‘only in America’, but in recent years it might be truer to say, ‘only in Dubai’, especially when it comes to architectural wonders. Buildings that would be unfeasible just about anywhere else seem to regularly spring from the ground in the oil rich emirate. The next eye-popping construction to grace the skyline could be a seawater vertical farm that uses seawater to cool and humidify greenhouses and to convert sufficient humidity back in to fresh water to irrigate the crops.
At a time when the world’s population continues to grow, arable land is under threat from deforestation, poor management and global warming. All these factors point to vertical farming being an idea whose time may finally have arrived - and what better place to put it to the test than Dubai. That’s the thinking of Italian architectural firm Studiomobile, who have been working on housing and infrastructure projects in the United Arab Emirates where a lack of fresh water and a high soil value make such a concept feasible.
The vertical farm features a soaring spire with pod-like ‘sky-gardens’ branching off to give it an organic feel in keeping with designers aims to create a clean, green, sustainable source of food for a more self-sufficient Dubai. The concept makes use of the Seawater Greenhouse process, which uses seawater to cool and humidify the air that ventilates the greenhouse and sunlight to distill fresh water from seawater to enable the year round cultivation of high value crops that would otherwise be difficult or impossible to grow in hot, arid regions such as Dubai. This is in stark contrast to costly and energy intensive desalination plants that rely on boiling and pumping to produce fresh water.
The concept works by continually cycling through three phases. In the first phase the air going into the greenhouse is first cooled and humidified by seawater, which is trickled over the first evaporator to provide a fresh and humid climate for the crops. Then in the second phase as the air leaves the growing area it passes through the second evaporator, which has seawater flowing over it. The humid air mixes with the warm dry air of the ceiling interspace making the air much hotter and more humid. The third and final phase sees the warm air forced upward by the temperature induced stack effect. In the central chimney the warm and humid air condenses when it comes in contact with plastic tubes that contain cool seawater. The drops of fresh water that appear on the surface of the condenser fall into a collection tank to be used to water the crops and for other uses.
At present the design is only a concept, but given Dubai’s love of distinct architecture coupled with their almost complete reliance on trade for food and deficiency of arable land and fresh water, don’t be surprised to see Studiomobile’s seawater vertical farm design appearing on Dubai’s skyline in the future. And if it proves successful there the lessons learned there could see the concept adapted to help feed ever growing cities around the globe and tackle the food shortages that look set to plague the world as global warming’s effects take hold.