Buildings that naturally react to environmental conditions, expanding and contracting to control airflow, breathing as if they are alive, sound like the stuff of fantasy. Yet, over the next three years, European researchers aim to construct passive ventilation systems not from concrete or steel, but from a wood-based foam.
The project is called Archibiofoam, a collaboration between Finland's Aalto University, the University of Stuttgart and the University of Milan. It was recently awarded a 3.4 million euro European Innovation Council Pathfinder Grant, which the researchers say will result in Archibiofoam's proof-of-concept: exterior building facades with porthole-like openings that open and close in response to the environment.
As Strong as Concrete, Minus the Emissions
Construction is the world's highest polluting industry by a longshot, accounting for roughly 40% of annual global emissions. So-called "bio foams" derived from extruded wood cellulose have the potential to revolutionise the industry, according to Aalto University's Juha Koivisto.
'Not only will we show that wood-based foam can be used as a replacement material, but we will also demonstrate its unique ability to respond to environmental factors like heat and humidity to enable the passive heating and cooling of buildings -; an improvement on the carbon footprint of existing building infrastructures by several orders of magnitude,' Koivisto says.
If executed successfully, wood-based foams could replace typical non-renewable and resource-intensive building materials like concrete, steel, and glass. The bio foam has comparable strength to these materials, even though it is composed of 90% air, and it is biodegradable, therefore adhering to circular economy principles.
'The scientific community has known for some time that the structural integrity of these bio foams is competitive with other construction materials, but it hasn't been tested to its full potential,' says Koivisto. He is inspired by a vision of organic buildings reminiscent of Gaudí's Barcelona, with ventilation chambers opening and closing naturally.
'It sounds like science fiction, but it's real and exciting stuff. Our goal over the next three years is to prove this material's efficacy as a bona fide building material,' says Koivisto.
Koivisto's local team includes Senior Lecturer Kirsi Peltonen and Postdoctoral Researcher Taneli Luotoniemi, both of whom come from Aalto's Department of Mathematics and Systems Analysis. The Aalto team will coordinate the project and provide the overarching material technology.
4D Printing with Foam
Robotics expertise is provided by Tiffany Cheng, research group leader at the University of Stuttgart's Institute for Computational Design and Construction. Her team is responsible for tuning the massive 4D printer used in extruding the wet foam material, a method of robotic additive fabrication that unlocks the performance potential of bio foams at large scale.
So-called 4D printing enables the programming of printed objects so that they autonomously transform in response to environmental stimuli. Digital design and robotic fabrication of bio-derived foams offers the chance to create adaptive architecture – it could drastically reduce the carbon footprint not only in the materials manufacturing process, but also throughout the lifecycle of the building. In this case, researchers can control the foam's contraction and expansion to respond to heat and humidity.
'Robotic additive fabrication is particularly well suited for structuring materials at high resolution, thereby unlocking the performance potential of wood-based bio foams at large scale,' Cheng says. 'By tailoring the mono-material system through our manufacturing process, we aim to meet the multiple functional requirements of building components, such as load-bearing capacity and shape change for adaptive ventilation.'
University of Milan Professor Stefano Zapperi is an expert in the automatic generation of digital, 3D models. Using proprietary software, his team will specify the design parameters for the algorithms to prioritize, such as heat and humidity sensitivity, to yield the most controllable results.
'We are currently witnessing a revolution in structural design thanks to algorithms that can find the most effective geometry for a desired function, such as programming shape changes under external stimuli. Throughout the Archibiofoam project, we plan to expand the capabilities of our software and to adapt it to the physical characteristics of the bio foam and to the needs of the building sector,' Zapperi says. 'I foresee a pipeline in which the architect only specifies his requirements in terms of shape, mechanical characteristics and response functions, and the computer yields a digital 3D model that is ready to be fabricated on a large scale.'
Packed with Industrial Potential
While the 3-year proof-of-concept project is about to launch, the bio foam material itself has already been researched for over a decade, initially as a climate-friendly packing material. Industrial partner, Woamy, has already built a business in bio foam technology. According to CEO Susanna Partanen, plans are underway to establish their first pilot factory, projected to be operational by 2026.
'As an Aalto University spinoff, Woamy is at the forefront of developing this novel bio foam technology. Our deep roots in this innovation are vital in bringing the Archibiofoam project to life. Through this collaboration and by leveraging our expertise, we aim to showcase how Woamy bio foam can not only transform the packaging industry but the construction industry as well.' Partanen says.