evaporator

Researchers at the University of South Australia have designed a self-sustaining solar-driven system that turns seawater into fresh water and grows crops without any involvement. In theory, such a system could help address the growing problems of freshwater shortages and inadequate food supplies as the world’s population continues to increase.

The system can be described as a vertical floating sea farm. It is made up of two chambers: an upper layer similar to a greenhouse and a lower chamber for water harvesting.

Clean water is supplied by an array of solar evaporators that soak up seawater, trap the salts in the evaporator body and, heated by the sun, release clean water vapor into the air which is then condensed on belts that transfer the water into the upper plant growth chamber.

The researchers tested the system by growing broccoli, lettuce and bok choi on seawater surfaces without maintenance or additional clean water irrigation. The system was powered entirely by solar light.

The design is only a proof-of-concept at this point. The next step is to scale it up using an array of individual devices to increase plant production.

The futuristic potential for such technology would be huge farm biodomes floating on the ocean. The UN estimates that by 2050, nearly 2.5 billion people are likely to experience water shortages while the global supply of water for irrigation is expected to decline by 19%. Nearly 98% of the world’s water is in the oceans. Harnessing the sea and the sun to address growing global shortages could be the way to go.

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Floating sea farms: a solution to feed the world and ensure freshwater by 2050

Photo, posted February 11, 2015, courtesy of Ed Dunens via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Water security is a serious global problem. Nearly 1.5 billion people – including almost half a billion children – live in areas of high or extremely high water vulnerability. Less than 3% of the world’s water is fresh and demand for it is rising with increasing population growth, urbanization, and growing water needs from a range of sectors.

Researchers at the University of South Australia have developed a promising new technique that could help reduce or eliminate water stress for millions of people. The technique uses highly efficient solar evaporation to obtain fresh water from seawater, brackish water, or even contaminated water. According to the researchers, their technique can deliver enough daily fresh drinking water for a family of four from just one square meter of source water.

Solar evaporation has been the focus of a great deal of effort in recent years, but it has generally been found to be too inefficient to be practically useful. The new technique overcomes those inefficiencies and can deliver fresh water at a fraction of the cost of existing technologies like reverse osmosis.

The system utilizes a highly efficient photothermal structure that sits on the surface of a water source and converts sunlight to heat, focusing energy precisely on the surface to rapidly evaporate the uppermost portion of the liquid. The technique prevents any loss of solar energy and even draws additional energy from the bulk water and surrounding environment.

The system is built entirely from simple, everyday materials that are low cost, sustainable, and easily obtainable.

The technology has the potential to provide a long-term clean water solution to people who can’t afford other systems, and these are the places where such solutions are most needed.

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Sunlight to solve the world’s clean water crisis

Photo, posted November 13, 2016, courtesy of Steve Austin via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Floating Sea Farms | Earth Wise

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A Better Solar Evaporator | Earth Wise

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