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Materials Energy

56: Buildings made of organic materials

Problem:

The vast majority of large buildings in the world are still made with energy intensive, inorganic single-use concrete and steel.

Solution:

Buildings incorporating algae and other nature-sourced materials.


In 2012, one of the world’s largest engineering/development/construction companies, Arup, teamed up with Splitterwerk Architects of Graz, Austria, Colt, and Strategic Science Consult to design and build a five-storey 15-apartment residential building in Hamburg, covered by panels filled with algae, a fast-growing form of biomass.

The panels are on the  two south-facing sides to help provide internal shading, and the micro-algae growing in the glass louvers provide a clean source of renewable energy.

Called Solar Leaf, the building pumps water, nutrients, and compressed CO₂ between 129 “bioreactors.” These bioreactors have four glass layers. The two inner panes have a 6 gall (24-li) capacity cavity for circulating the growing medium.

Either side of these panes, insulating argon-filled cavities help to minimise heat loss. The front glass panel consists of white anti-reflective glass, while the glass on the back can integrate decorative glass treatments.

Compressed air is introduced to the bottom of each bioreactor at intervals. The gas emerges as large air bubbles and generates an upstream water flow and turbulence to stimulate the algae to take in CO₂ and light. At the same time, a mixture of water, air and small plastic scrubbers washes the inner surfaces of the panels.

SolarLeaf integrates all servicing pipes for the inflow and outflow of the culture medium and the air into the frames of its elements.

When the sun shines, the algae multiply as a result of photosynthesis. The system collects the residue, then converts it to biogas, which is burned in a boiler. Together with a heat recovery system and solar panels on the roof, the building is completely energy independent.

The system can be operated all year round. The efficiency of the conversion of light to biomass is currently 10% and light to heat is 38%. For comparison, PV systems have an efficiency of 12-15% and solar thermal systems 60-65%.

The flat photo-bioreactors are highly efficient for algal growth and need minimal maintenance. The building, also called BIK, completed in 2013, was part of Hamburg’s International Building Exhibition. (arup.com)

In 2015, Guglielmo Carra of Arup Berlin working with Kasper Jørgensen of GXN Innovation in Copenhagen, developed BioBuild, the first self-supporting façade panel made out of bio-composite materials.

Developed as part of the €7.7 million EU-funded BioBuild program, the design reduces the embodied energy of facade systems by 50% compared to traditional systems with no extra cost in construction.

The 13 ft x 7.5 ft (4m x 2.3 m) panel is made from natural flax fabric and bio-derived resin from agricultural processing of corn, sugar cane and other crops.

Intended primarily for commercial offices, the glazing unit features a parametrically-derived faceted design, and comes prefabricated ready for installation. The panel is also designed to be easy to disassemble, making it simple to recycle at the end of its life.

The panel won the JEC Award 2015 for the best composites innovation in the construction field. (gxn.3xn.com)

In 2017, Arup published a report entitled “The Urban Bio-Loop: Growing, Making and Regenerating” in which it demonstrates that a different paradigm for materials in construction is possible. The report highlights the following organic matter products already available: peanut, rice, banana and potato.

What you can do: Tell local architects and builders about the Arup Bio-Loop

Discover Solution 57: The extraordinary tale of 80 thousand silent buses.

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