Prototype of coupled bilayered planks: The planks of the automated shading system are in a vertical position when relative humidity is high (left) and bend when when humidity is low (right). (Photograph: Chiara Vailati / ETH Zurich)
This apparently simple idea required years of research. Vailati had to master two challenges in particular. Firstly, it was necessary to increase the initially very small bilayer structures to the standard plank length of half a meter, without the material deforming uncontrollably. Secondly, the system reacted too slowly compared to conventional motorised planks. “I had to find a way to accelerate the bilayer kinetics,” says Vailati. Striped patterns in the wood and a finely adjusted ratio of layer thicknesses helped to speed up the movement. Finally, Vailati also made use of her experience as a civil engineer: to increase the amount of shade, she coupled the bilayered planks. “That significantly increased the reaction time,” she says happily.
ETH Zurich patented her invention. And Vailati defended her doctoral thesis in February, and recently started work as a postdoc at Empa in the Building Energy Materials and components Group. A small prototype of her shading device can still be found on the roof of an ETH building on the Hönggerberg campus. Particularly on days like these its pleasantly cool shade would be blessing.
The patent-pending shading device was counted among the best 20 inventions by ETH transfer last year and can be
licensed (PDF, 368 KB)
. More information is available
here
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