Researcher Michel Maharbiz from the University of California, Berkeley, together with researchers from the University of Michigan, and MIT have constructed leaves out of glass wafers with tiny veins through which water can flow. Electrical power can be scavenged from evaporation-driven flow via a charge pump embedded in the 'stem'.
Source: Maharbiz Research Group
The leaves suck water from the main stem at 1.5cm per second and the veins open at the edges of the glass leaves where evaporation takes place. The actual power production takes place in the leaf's central stem walls, which are lined with metal plates connected to a circuit. By charging the metal plates, the researchers created a capacitor made from the two conducting plates separated by an insulating layer. Air bubbles periodically interrupt the flower of water and due to the different electrical properties of air and water, each time an air bubble passes through the plates, an electric current of about 2-5 microvolts is generated. This electricity can then be harvested to power small devices, although the power density of this process is still very low, the researchers feel it carries potential.
Top image source: Fine Art America
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