Preserving Chile's water with solar-powered robots

© 2018 EPFL - The scientists' team in Chile, where they tested modular origa
© 2018 EPFL - The scientists' team in Chile, where they tested modular origami robots preventing water from evaporating.
EPFL researchers have developed floating, solar-powered robots to help protect Chile’s water reservoirs. These low-cost robots can be assembled together in a variety of ways on the water surface to prevent the water from evaporating - thereby preserving a precious resource in this arid country and one that’s crucial to its biggest industry: winemaking.

Preserving water is a real challenge in hot, dry parts of the world. "Farmers in these countries often cover water reservoirs with thousands of tiny plastic balls, a kind of tarp or a large umbrella to prevent the water from evaporating. But these systems can be expensive to set up and take down - and they can’t adapt to the water surface as evaporation causes it to change size and shape," says Jamie Paik, the head of EPFL’s  Reconfigurable Robotics Lab  (RRL) and a professor at the School of Engineering. Researchersfrom RRL, working in association with a scientist from Universidad Adolfo Ibáñez in Chile, have developed a water-preservation system tailored specifically to Chile’s winegrowing region as part of a project sponsored by EPFL’s  Cooperation & Development Center.

Robust, flexible and modular origami robots

Their system involves robots that look like little floating tiles. Powered by embedded solar panels, they can assemble themselves automatically on the water surface and move as it changes size and shape. "The idea isn’t necessarily to cover the entire water surface but to have the robots follow the sun and avoid shady spots. That means the robots would continuously cover places where the water evaporates - and it would minimize the number of robots needed," says Paik. 

Researchers are also looking into other ideas, such as using floating robots not to cover the water surface but to unfold and fold up a tarp automatically based on the shape of the water surface. These robots would be much easier to move around than plastic balls or a mounted tarp and could automatically adapt to changes in water levels. What’s more, the solar energy generated by the researcher’s robots could be a boon to sunny regions. Two  RRL  scientists - Jianlin Huang and Frédéric Giraud - tested the robots’ power-generating capacity on Lake Geneva before heading to Chile; they found that in just half an hour, a robot could generate enough power to fully charge a smartphone.

Responding to a pressing global need 

"We saw how urgently a system like ours was needed as soon as we arrived in Chile," says Paik. The temperature and amount of sunlight in the country’s regions can vary drastically from one day to the next, resulting in substantial fluctuations in water-reservoir shapes and making existing methods ineffective. Many of Chile’s vineyards are run by cooperatives of small families that can’t afford to invest in complicated, costly systems. And its economy depends heavily on wine production in a country prone to crop-ravishing droughts. 

The RRL team intends to further their research and finalize their technology. Farming cooperatives could eventually be interested in collectively purchasing the little robots. But that’s not the only potential application - some 20% of the world’s population lives in areas where water is scarce. 

The pictures display the Ivanhoe pond in California and a solution offered in Australia, as well as the researchers in Chile.