A Shape-Shifting, Heat-Sensitive Metal Lets Buildings Breathe

Thermobimetal, a laminate building material that changes shape as temperatures rise and fall, could enable structures that react smartly to their ever-changing environments.

Ever since we stepped out of thatched roof huts and into modernity, our buildings have been out of whack with the environment, relying on air conditioning and other systems to keep us comfortable. Developing buildings that self-regulate their temperatures–what’s known as homeostatic architecture–is more difficult than it sounds, and the perfect, uncompromising homeostatic construction remains one of architecture’s holy grails.


Back in August, we wrote about a group of designers who are using wood to create building facades that open and close according to humidity. Now, research by USC architecture professor Doris Kim Sung proves that a similar logic can be applied to a radically different material: metal.

“Skin is the first line of defense for the body,” says Sung, who was a biology student at Princeton before turning to architecture. “Our building skins should be more similar to human skin.” Speaking at an October TED talk, Sung presented her research on thermobimetal, a material made by laminating two metals of differing thermal expansion coefficients. When it gets hot, the two different sides expand at different rates, which causes the thermobimetal to curve.

Demonstrating the unique properties of an exotic material is one thing–actually building with it is quite another. Remarkably, Sung is already well on her way down that road. This summer, her studio, DO|SU, unveiled Bloom, an installation at L.A.’s Materials and Application Gallery that tested a thermobimetal in a full-scale structure. The pavilion is made from 14,000 individually laser-cut pieces of the stuff, woven into a steel framework that balloons over the outdoor site (Sung compares its shape to a Victorian corset).

“As the sun moves across the surface, each of the tiles move individually,” explains Sung. Watch the time-lapse video above, and you’ll see that Bloom curls and morphs to accommodate the changing environmental conditions around it. Each panel is perforated with a unique pattern, calibrated to the angle of the sun and its exact location on the structure. Bloom operates as a shading device, but also as its own ventilation system; when it’s hot, the surface curls to let more air pass through.

DO|SU is working on several more robust tests–in particular, a design for a home in China with an entire facade made of thermobimetal. Sung is also developing a set of simple thermobimetal building components, like a window embedded with flower-like pieces of the metal which curl to provide natural sun shading. Particularly neat are her studies of ventilation systems based on the way crickets breathe, pulling in air from tiny holes in their body rather than a single airway. In her drawings, thermobimetal curls or distends to allow airflow into thousands of tiny facade perforations. “When you’re tired of opening and closing the blinds, or there’s a power outage,” adds Sung, “these thermobimetals will still be working–tirelessly, efficiently, and endlessly.”

[H/t ArchDaily]


About the author

Kelsey Campbell-Dollaghan is Co.Design's deputy editor.