Algae façade makes house truly 'green'

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Algae façade makes house truly 'green'
Photo: BIQ

An innovating new building in the northern German city of Hamburg is hoping to harvest heat from its algae-covered façade. Jeff Kavanagh reports.


For many of us, the concept of living in a place with stuff growing on its walls won’t necessarily be foreign. What will be unusual for those who have experienced the joys of residing in damp student flats and first homes away from the parental nest, however, is the idea that microorganisms flourishing on your walls is a good thing.

This is precisely the logic at work in the construction of a state-of-the-art apartment building in the once rundown, but increasingly trendy riverside quarter of Wilhelmsburg in Hamburg. Clad on its two south-facing sides with a transparent shell housing millions of microalgae, the five-storey Bio Intelligence Quotient (BIQ) house has been designed to harness heat generated by the microscopic plants and use it to warm building’s 15 apartments.

Know as a “bioreactor façade”, the shell works on the principle that the microalgae, most no bigger than bacteria, are cultivated through the supply of sunlight, liquid nutrients and CO2, a process that produces heat.

“The reason we are using microalgae is because they have higher efficiencies than any other crops, especially for energy purposes,” explained Dr Stefan Hindersin, a biologist with Strategic Science Consult (SSC), the firm behind the development of the façade’s technology.

In fact, the algae, sourced from a tributary of the Elbe River, the body of water that flows around Wilhelmsburg, produce up to five times as much biomass as terrestrial plants. This biomass can then be processed to produce biogas, albeit at a different location from the building itself.

Part of the Internationale Bauausstellung (IBA) - “The International Building Exhibition” - 2013, a multi-disciplinary, multi-million euro project funded by the government of Hamburg and scheduled to open on March 23rd, the BIQ house is one of 16 innovative buildings designed to transform the centre of Wilhelmsburg from a “brownfield” – land previously used for industrial and commercial purposes - into liveable space with housing, retail space, hotels, leisure facilities, and green areas.

The first building in the world to feature a bioreactor façade, the idea to build its external shell arose from a dilemma.

“We realised we were getting overheating problems in our photo bioreactors,” Hindersin told The Local. “Then we thought ‘OK, where do we need a lot of heat?’”

The answer was in buildings and the solution, he said, was to put the photo reactors on the walls of the BIQ house.

The façade is not expected to take care of all the building’s heating requirements, however. Instead, it will be a component of what the IBA website describes as the BIQ house’s “holistic energy concept”. This concept involves the BIQ house producing renewable sources of energy, such as solar and thermal, and being part of Wilhelmsburg Mitte’s integrated energy network, a network of local buildings also generating energy and linked to a main bio-methane plant.

Should the façade generate too much heat (for example, in summer when the building’s needs are lower), the energy can then be stored in buffers for later use or sold back to the local grid, Hindersin explains. In constant motion and changing colour as the algae grow, the shell will further benefit the BIQ house by insulating it from sound, heat and cold, and providing the building with shade on sunny days.

Unsurprisingly, the €5-million building’s futuristic innovations are not limited to its exterior. Inside, two of the apartments will not have separate rooms, thereby allowing their inhabitants to configure them as needed.

According to the IBA website, “the individual functions of the apartment – bathroom, kitchen, sleeping area – can be swapped about or combined to form a ‘neutral zone’”. The logic is that in the future, with lines between living and working spaces less defined than they are now, there will be a greater demand for adaptable housing spaces.

An ambitious project inside and out, perhaps one the project’s most intriguing aspects, in the end, is the choice of Hamburg, a city famous for its long winters and inconsistent summers, as the testing ground for its sunlight dependant façade.

“It isn’t the best location, it’s even quite bad if we compare it with southern Europe or the sub-Sahara,” admitted Hindersin. “But, our belief is that if we can get this running in Hamburg, we can do it nearly everywhere.”


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