Thermal bi-metallic strips with different coefficients of thermal expansion can be combined or interlaced to create canopies or shading devices for buildings. The combination of two metal alloy sheets convert temperature changes into mechanical displacement.
Laminated alloys of iron, nickel and manganese combined with aluminium strips have been combined to make shading structures. Thermal bimetals can maintain their shape using tension only, requiring no fasteners in their construction. Doris Kim Sung pioneered many of the bimetal structures, arranging the metal as "pores" which open in response to heat. The image below shows a sculptural shading device by Sung:
Doris has an intriguing Ted talk featuring the picture above. Studio Roosgaarde in the Netherlands created a similar responsive structure in a dome-shape which uses ultralight aluminium and mylar foils, and combines them with sensors,lights and software to activate the apertures.
Benefits and Drawbacks
Thermal bi-metals offer opportunities for heat-sensitive automatic shading and cooling applications. Thermal bimetals are not currently mass-produced.
Commercial Readiness
Thermal bimetals have not been commercialized yet. They have only been used for unique small-scale projects so far. Their potential as shading devices for towers provides a strong case for mass production and commercialization.
