In what may be one of the most eye-catching recent symbols of the spirit of Earth Day in the green building movement, a new apartment complex in Hamburg, Germany, has opened with two unique green walls. These aren’t the kind with plants attached to the outside skin; these walls are actually made of tiny, energy-producing plants suspended in water-filled chambers.
In the 15-unit block of flats, knows as the Bio Intelligent Quotient (BIQ) House, algae is the plant of choice not only to green up the exterior but also provide power in the form of biogas to help provide heat to the units. In addition, the long, rectangular glass chambers that contain the solution of water and algae can be adjusted to follow the movement of the sun, much like solar panels, and provide cooling shade for the residents on the southeast and southwest sides.
Created by global engineering and design firm Arup, Germany-based SSC Strategic Science Consultants and Austria-based Splitterwerk Architects, the €5 million BIQ House turned heads during its debut at Hamburg’s International Building Exhibition in March and will have an official opening on April 25. The 129 panels, or “bio-reactors,” on the BIQ House each measure 8 feet tall and 2 feet wide. Inside the louvered glass chambers, algae collected from the nearby Elbe River are automatically supplied with the proper balance of water, nutrients and CO2 to promote growth.
After the growth has reached its maximum sustainability, the panels are opened and the algae are harvested in a pulpy mass for fermentation into biogas fuel, and the process is started again. Although the algae itself are microscopic, they add up quickly. According to Splitterwerk, the tiny plants produce about five times as much pure biomass, by weight, as terrestrial plants.
Depending on the angle and intensity of the sunlight, the panels will appear in ever-changing shades of green as the algae grow at different rates. During the summer months, when photosynthesis and algal growth should be most intense, the panels will appear become opaque, providing more shade to prevent solar gain. Excess heat collected by the panels will be transferred to saline tanks for later use, Arup says. In the winter, the panels will be mostly transparent, allowing more passive solar energy to heat the building.
“To use bio-chemical processes for adaptive shading is a really innovative and sustainable solution, so it is great to see it being tested in a real-life scenario,” said Arup research leader Jan Wurm, in a recent Dezeen article. “As well as generating renewable energy and providing shade to keep the inside of the building cooler on sunny days, it also creates a visually interesting look that architects and building owners will like.”
It is assumed that the concept will do well in sunnier tropical climates, so, for the next several months, the five-story BIQ House will serve as a test case to determine if the “bio-adaptive façade” design will be feasible in northern-latitude areas such as Hamburg, which has limited sunlight year-round, Arup says.