The solution to nagging global drinking water shortages need not be expensive as university researchers show the world how: through a solar-powered water purifier.

In the journal Global Challenge published Jan. 30, a group of academics outlined the concept that may solve the problem of access to safe drinking water worldwide particularly in depressed communities and regions hit by natural calamities.

The team utilized cheap materials "to create a system that makes near maximum use of the solar energy during evaporation," says lead researcher Qiaoqiang Gan, an associate professor at the University at Buffalo. He is joined by other academics from UB's Department of Chemistry, Fudan University in China, and the University of Wisconsin-Madison.

Generating Drinking Water To Every Home Better, Cheaper

Water is everywhere but, as former UN Secretary General Ban Ki-moon said, is "increasingly vulnerable and threatened" where some 663 million people do not have access to safe drinking water.

Taking cue from solar panels that energize homes, Gan said the new model will make access to safe drinking water affordable especially in poor communities.

The team developed a prototype solar still — the size of a small refrigerator — to purify salt water using the heat from sunlight. The process is almost straightforward: The water is evaporated using sunlight and moves into gaseous state leaving behind the salt and other impurities as residues. Once the water vapor returns to liquid state, it is stored in a container sans salt and other unwanted elements.

The device, called as "water vapor generator", is both efficient and affordable.

Research leading co-author Haomin Song observed that most devices are inefficient in a sense that it loses so much heat energy during the evaporation process. Some systems are also costly because they "require optical concentrators ... to concentrate the sunlight."

To address the issues of cost and efficiency, the researchers developed a device almost the size of a mini-refrigerator made of a common plastic to serve as thermal insulator and a rough paper coated in carbon black. The paper absorbs water while the carbon black absorbs the needed sunlight for water evaporation where, the UB-led team noted, only 12 percent of the available solar energy lost in the process.

The study showed that the new still can produce as much as double compared to commercial ones which can produce only 1 to 5 liters in a day. As to the cost, the new device costs less than $2 in every square meter — a huge difference from $200 for every square meter of the black-bottomed commercial devices.

With the cheap cost the new device entails, it will be good news not only to impoverished regions but also to aid workers in calamity-stricken communities.

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