Self-Sustaining Structures

By Sofia Zamora, E.I.T.

Building envelopes are structures that must insulate and protect the interior of a building from external agents and noise, from gaining or losing heat, and from letting moisture in or out.  Traditionally, envelopes are designed to have a man-made look to be sturdy enough to sustain the local wind, snow, and seismic loads, and to be insulated enough to sustain temperature, moisture, and sound loads.  Recently, however, there has been a growing interest in new design trends which are aimed at further developing the concept of the building envelope. 

The advancement of the building envelope through Biophilic and Biomimicry design concepts, for instance, has been outstanding.  Proponents of these trends aim to integrate nature into the built environment thus exploring the potential benefits of this type of synergistic relationship.  Biophilic Design started as an architectural movement that sought to introduce the natural world into the built environment with the belief that this contiguous relationship has a positive influence on humanity, promoting our health and, in turn, improving our physical performance.  This design trend upholds that a building should be capable of inspiring and invigorating its users.  Biomimicry, on the other hand, focuses on understanding the functional strategies of nature and how these systems can be incorporated into the overall concept of a building.  Biomimicry attempts to implement these strategies at every level of a building’s design and, in this way, create a single interdependent system.  Nowadays, architects and engineers of all disciplines are coming together to explore how Biophilic and Biomimicry concepts can be incorporated into their specific fields to create more sustainable and more efficient structures.  These explorations have resulted in buildings powered by solar or wind energy as well as the development of vegetated double skin facades.  This type of live facade maximizes the benefits of plants by utilizing them as the main layer of thermal and sound insulation.

A prominent firm based in Germany, Arup, has pushed the development of the live façade movement with a specific focus on researching ways to maximize the incorporation of Biomimicry and Biophilic design into their buildings.  This firm developed the first bio-adaptive façade system of micro-algae by combining the latest energy and environmental engineering technologies.  It is currently being showcased for the first time at the BIQ building as part of the International Building Exhibition in Hamburg, Germany.  

The façade is composed of bio-reactive louvers that enclose algae and harvest it in order to process bio-gas which will allow the BIQ building to operate completely independent from fossil fuels.  The algae in the louvers are continuously supplied with liquid nutrients and carbon dioxide through a separate water circuit running through the façade.  The algae are grown and controlled through a bio-chemical process to provide the building with shading and are allowed to flourish and multiply in a regular cycle until they can be harvested.  They are then separated from the rest of the algae and transferred as a thick pulp to the Technical Room of the BIQ where the pulp is fermented in an external biogas plant and used to generate bio-gas.  This algae produces up to five (5) times as much bio-gas as terrestrial plants. 

 Additionally, the facade is able to collect the remaining solar energy which is not absorbed by the algae and generate enough power to heat water, provide heating, or be stored in the ground using borehole heat exchangers.  This incredibly sustainable design has maximized the concept of closed-loop energy by maximizing the collection of solar energy in a fashion similar to a tree. 

 Not only does this façade provide all the energy necessary to run this building but it also serves the conventional building envelope purposes of insulating the building from sound, heat, and cold, controlling light, and providing shade.  I cannot wait to see how the continued integration of Biophilia and Biomimicry into building design will evolve our cities.