Monday, February 16, 2004 - A Solar Twist on Desalinization

Solar power may help ease the severe water problems facing a growing number of nations:

Desalinization has long held the promise of helping the world solve its pressing water needs, yet widespread implementation has not occurred because current systems are costly and require large amounts of energy. But engineers at the University of Florida (UF) have turned to nature for a solution that could make desalinization a viable option for those in need.

"We know that nature uses solar energy to get fresh water from salt water," said Yogi Goswami, a professor of mechanical engineering and director of UF's Solar Energy and Energy Conversion Laboratory. "We use the same process as nature, except we enhance the process."

Nature's process for desalination is as follows: fresh water evaporates from the ocean, forms clouds, condenses and falls to the ground as rain. Goswami says he and his colleagues sought to recreate and enhance this process by exploiting solar energy and natural barometric pressure.

The new system uses a gravity induced vacuum and solar energy instead of electricity or fossil fuels to desalinate water, Goswami explained.

The researchers say the system is more efficient than previous solar "stills" for removing salt, but is simple and inexpensive enough to be built in remote locations where conventionally powered technologies would be either too expensive or impractical. This could prove critical, as lack of potable water is a growing problem worldwide.

The World Water Development Report, released this year by the United Nations, says many countries in the Middle East, Africa and Asia currently face severe water crises, and the number is likely to grow in coming years under the dual pressures of increasing populations and worsening pollution.

The report finds that within 50 years, seven billion people in 60 countries could face water scarcity.

An experimental version of the system was ninety percent efficient, although it only produced a half cup of fresh water an hour. How much it could be scaled up remains to be seen.


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