Bloom illustrates the emulation of botanical behavior in non-biological materials. Designed by architect Doris Kim Sung, Bloom is a 20’ tall open-air pavilion clad in gleaming bimetallic strips—a composite skin designed to shape-shift with changes in temperature. Bimetals are made of two types of sheet metal with contrasting coefficients of thermal expansion, and are commonly used in thermostats and thermometers. In the presence of direct solar radiation, the exposed material expands at a faster rate, causing the laminated sheet to curve upwards.
Although bimetal transformation is based on a physical effect unrelated to biology, the phenomenon resembles solar-responsive behaviors found in plants. Circadian responses in particular involve plant movements in alignment with the diurnal cycle. The oxalis leaf or velvet leaf, for example, open during the day and close at night—exhibiting an awareness of changes in light and temperature. In similar fashion, the 14,000 bimetallic strips cladding the Bloom pavilion demonstrate clock-dependent feedback, and they curl and flatten with the presence and absence of sunlight, respectively. Rather than regulating biochemical activities or expressing genes, however, Bloom’s circadian response in directed towards temperature regulation for pavilion occupants. To this end, the bimetal strips provide additional shading and openings for ventilation during the peak hours of solar intensity.
The impetus for Bloom came from Sung’s interest in the capacity of architecture to adapt for human benefit, rather than the common requirement that occupants adapt to buildings’ environmental limitations. Her recognition that plants commonly respond to changing environmental stimuli, coupled with the fact that bimetals exhibit behaviors similar to this phenomenon, results in a compelling design application that portends a promising future for responsive architecture.
The story continues in Hypernatural, which explores architecture’s new relationship with nature.