Sippin' on Sunshine
Researchers at the University of Waterloo developed a low-maintenance, solar-powered desalination system that mimics nature's water cycle.
Water, water everywhere, and not a drop to drink. This lament made famous by Coleridge expresses the irony of being near the massive body of water that is the ocean, yet having no access to fresh water for drinking. This is not just the song of the lonely sailor — according to the United Nations, over two billion people worldwide lack access to clean sources of water.
That is a very significant slice of the global population, so solutions are sorely needed to help alleviate this problem. Desalination is a widely-used process that removes salt from seawater to produce drinkable water. This process has proven itself to be crucial for providing large populations, especially coastal populations, with access to clean water. However, current technologies are extremely energy-intensive. Moreover, the equipment gets clogged up with salt over time and requires frequent maintenance to stay operational. These factors increase the cost of these systems while simultaneously reducing their efficiency. And that, in turn, places them out of reach for many populations, especially in the developing world.
Listen to the trees
Engineers at the University of Waterloo have been hard at work on a new type of device that may help to solve these present issues with desalination systems. It is energy-efficient and relies on an evaporation process driven primarily by the sun to produce fresh, clean drinking water. It mimics how nature moves water through trees, making the desalination process continuous and virtually maintenance-free.
A key innovation is in the material used — a special nickel foam coated with conductive polymer and thermoresponsive pollen particles. This material absorbs sunlight and converts it into heat, warming a thin layer of saltwater that is transported upward. As the water evaporates, the salt naturally settles at the bottom, preventing blockages and keeping the device running smoothly. Approximately 93 percent of the sun’s light is converted into energy that powers the device, making it five times more energy-efficient than current desalination technologies.
Supplied with one square meter of saltwater, the device is capable of producing enough clean water each day to meet a person’s basic needs for both drinking and basic hygiene. The device is also portable, which makes it practical for use in even very remote regions of the world. Given the practicality and usefulness of the system, in conjunction with its low cost, the researchers believe that it could be an important tool in combating the emerging water crisis that many are experiencing. Toward that goal, the team is working on building larger prototypes to determine how well the technology can scale.