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Wenbin Wang
What could a solar panel and a water purifier look like?
Researchers have found a way to purify water and produce electricity from a single device powered by sunlight.
Scientists adapted a solar panel that produced energy, but also used some of the thermal energy to distil and purify seawater.
They believe that this idea could make a major difference in sunny climates where water supply is limited.
The lead author expects a commercial device to be available in five years.
Clean energy and clean water are among the main challenges of sustainable development, especially in emerging countries. But traditional methods of electricity production consume huge quantities of water. In the United States and Europe, about 50% of water withdrawals are for energy production.
Similarly, the production of water for humans by desalination in countries where water is scarce consumes a lot of energy. It is estimated that in Arab countries, about 15% of electricity production is used to produce drinking water.
Researchers now think they have found a way to combine these actions into one device.
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The desalination plants have gained popularity in recent years, but they consume a lot of energy
State-of-the-art solar panels face physical limitations on the amount of sunlight they can actually turn into electricity. Normally, about 10 to 20% of the sun striking the panel is powered. The rest of this heat is considered waste.
In this experiment, scientists designed a three-stage membrane distillation unit and attached it to the back of the photovoltaic panel (PV).
The membrane essentially evaporates seawater at relatively low temperatures. The researchers were able to produce three times more water than conventional fixed appliances while generating electricity with a yield greater than 11%. This meant that the device generated nine times more energy than what had been done in previously published research.
"The lost heat of photovoltaic panels has really been ignored, no one has thought about it," said Professor Peng Wang, senior author, of the King Abdullah University of Science and Technology in Saudi Arabia.
"We use heat to generate water vapor that is transported through the membrane and then condenses on the other side."
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There is a growing trend to install solar panels on water plans
"Since it is a multi-stage distillation apparatus, it also makes use of the latent heat of condensation to drive the second cycle of evaporation from the water." 39. That's why we can get a very high freshwater production rate. "
According to the authors, if the technology was developed and used on a global scale, it could theoretically produce 10% of the total amount of drinking water consumed in 2017.
However, there are many tricky steps to follow to develop and market this type of device. There are some disadvantages inherent in the fact that it requires a large area of land to collect enough sunlight to produce water effectively.
"It can be used for coastal areas as long as you are not talking about providing drinking water to a city of more than one million inhabitants," said Professor Wang.
"It is an appropriate technology to provide small and medium scale drinking water," he explained.
The study was published in the journal Nature Communications.
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