TECH

Solar steam generator produces clean water with almost 100% efficiency

Solar Desalination
Once again seeking inspiration in origami, the Japanese art of folding paper, researchers have developed a solar steam generator that is approaching 100% efficiency.Solar steam generators produce clean water by capturing the heat from the sun, which is used to evaporate sea water, leaving salts and other impurities behind. Then, the steam is collected and condensed in clean water.The existing solar steam generators contain a flat photothermal material, which produces heat from the absorbed light. Although these devices are quite efficient, they still lose energy by dissipating heat from the material into the air.Peng Wang and his colleagues at King Abdullah University of Science and Technology in Saudi Arabia have improved energy efficiency by three-dimensional photochemical material. They based their structure on the Miura technique of origami, which consists of interconnecting parallelograms to form mountains and valleys, forming a 3D structure.The solar vapor generator was manufactured by depositing a nanocarbon compound - light absorber - into a cellulose membrane that was structured with the Miura folding.The 3D device had a 50% higher evaporation rate than a standard flat device. In addition, the efficiency of the 3D structure approached 100%, compared to 71% for the 2D material.In comparison with the flat surface, the valleys of origami capture the light of the Sun better, so that less of it is lost by reflection. In addition, the heat can flow from the valleys to the colder mountains, evaporating water along the way rather than getting lost in the air.


Bibliography:Nature-Inspired, 3D Solar Origami Steam Generator Near Near Full Utilization of Solar Energy
Hong Seunghyun, Yusuf Shi, Li Renyuan, Zhang Chenlin, Yong Jin, Peng Wang
Applied Materials and Interfaces