A new greenhouse design by Danish architecture firm C.F. Møller ditches glass windows for high-tech cladding, which changes transparency to control the amount of sunlight that reaches the plants inside.
C.F. Møller was tasked with restoring a hothouse the firm originally designed for the Botanical Gardens at the University of Aarhus in Denmark in 1969, turning it into a cafe and educational center. In the process, the firm also erected a new, energy-efficient greenhouse. Almost 60 feet tall at its highest point, the building is oriented to capture the most possible sunlight in the winter, and least possible sunlight during the summer, and its exterior can be adjusted to provide more or less sun exposure for the university’s unique collection of plants.
The domed building is covered in ETFE foil cushions, a type of film that can be used as an alternative to glass. On the northern side, those cushions contain two layers of foil, making them essentially transparent. On the southern side, the cushions contain three layers of foil printed with complementary dot patterns. A mechanical climate control system directs naturally ventilated air into different parts of the ETFE foil cushions. When air is forced into one chamber, the dotted layers press together, making the screen opaque. When air is forced into the other chamber, the dotted layers are forced apart, making the screen more transparent.
It’s a clever way to ensure that the hothouse never gets overly hot.