Researchers and designers at Germany’s Fraunhofer Institute have developed a building façade element which uses the sun’s energy to shield the building’s interior from the sun.

The façade element consists of a matrix of individual fabric components which sit behind a glass window. In the prototype, there are 72 individual modules, shaped like flowers, in the matrix.

Each module has a shape-memory actuator built into it. These are thin wires of nickel-titanium alloy (80 millimetres long in the prototype). When these wires are bent, they hold their shape. But if they are heated, they return to their original shape; when cool, they become bent again.

When the façade is warmed by the sun, the wires are activated and re-shape themselves to open the textile modules and cover the exposed surface, so that the sunlight can no longer penetrate. When the sun disappears, the modules close again and the facade become transparent.

The sun shield can be easily retrofitted to either the outer layer of glass or in the space between glass panels in a multi-layer façade. The structure permits a range of design options, allowing the pattern, shape and color of the individual components to be chosen.

The researchers now want to collaborate with industry partners to develop a range of prototypes for private and office buildings. The goal is for the systems to be ready for market launch by mid-2017.