Researchers from the University of Buffalo have created a highly efficient device that uses sunlight and black carbon paper to clean water. The paper is placed in a triangular device that allows it to evaporate and absorb water with almost 100 percent efficiency. Simple, inexpensive technologies can be deployed in regions where clean drinking water is unavailable or areas that are severely affected by natural disasters.
"Our technology is capable of producing drinking water faster than theoretically calculated in natural sunlight," said lead researcher Qiaoqiang Gan. A solar concept that uses sunlight to purify water is ancient. Aristotle described this method more than 2,000 years ago. The difference lies in the ability of the new device to achieve ultra-high efficiency.
"Usually, when solar energy is used to evaporate water, some of the energy is lost, as heat is lost in the environment," explains Gan. "This makes the process less than 100% effective. Our system has a way of removing heat from the environment, which allows us to achieve near-perfect efficiency."
Inclined orientation on a carbon base is key to achieving this efficiency by allowing the lower edges to absorb water, and the outer coating absorbs the solar heat that should be used for evaporation.
The research team gave priority to simplicity and accessibility in its design. "Most groups working on solar evaporation technologies are trying to develop advanced materials, such as metallic plasma and carbon nanomaterials," Gan said. "We focused on the use of extremely inexpensive materials and still managed to realize record figures."
Thanks to the recently launched launch of Sunny Clean Water, the team hopes to expand access to its device for needy areas. "When you talk with government officials or non-profit organizations working in disaster areas, they want to know: how much water can you generate every day? We have a strategy to increase daily productivity," says Haomin Song, a graduate of electrical engineering. "With solar still the size of a mini fridge, we estimate that every day we can generate from 10 to 20 liters of clean water."