The HygroSkin – Meteorosensitive Pavilion by Achim Menges Architects adopts an organic mode of climate-responsive architecture, in every sense of the word.
Created by Menges, a professor at the University of Stuttgart, Germany, the pavilion project features an architectural skin that autonomously opens or closes in response to its surrounding climate without the use of any mechanical and electronic sensing, or actuating and regulating devices.
Menges calls his Pavilion, which was exhibited in the FRAC centre in Orleans, France, an example of a ‘novel mode’ of climate responsiveness, differing from past methods of meteorosensitive architecture.
“While most attempts towards environmental responsiveness heavily rely on elaborate technical equipment superimposed on otherwise inert material constructs, this project uses the responsive capacity of the material itself,” says Menges.
The Hygroskin Pavilion therefore stands out from past projects of its kind by considering the responsiveness — the life — of the material in its organic form, specifically, the ingrained climate responsiveness of the building material itself.
This material is organic, untreated timber, which was used in the architectural skin design. Unlike builders and designers who go to great lengths to inhibit the expanding and shrinking of wood as it dries and gathers moisture, the Pavilion capitalises on the dimensional instability of wood.
As a result, the timber structure of the Pavilion is given the freedom to essentially ‘be itself’ and adapt (not be adapted) to suit the climate — its ‘windows’ autonomously open and close and its walls shift and bend according to the ambient relative humidity at hand and according to the hygroscopic behaviours of the timber materials.
This is achieved with weather-responsive apertures, which are placed within the deep, concave surface of each robotically fabricated module.
Above [L&R] : The Pavillion's 'windows' open and close according to weather conditions. Image: achimmenges.net
“Materially programming the humidity-responsive behaviour of these apertures opens up the possibility for a strikingly simple yet truly ecologically embedded architecture in constant feedback and interaction with its surrounding environment,” Menges explains.
According to the architects, the tension between an archetypical architectural volume and a deep, undulating skin imbedding clusters of intricate, climate responsive apertures is explored:
“The pavilion’s envelope, which is at the same time [a] load-bearing structure and metereosensitive skin, is computationally derived from the elastic bending behaviour of thin plywood sheets. The material’s inherent capacity to form conical surfaces is employed in combination with seven-axis robotic manufacturing processes to construct 28 geometrically unique components housing 1100 humidity responsive apertures. The changing surface embodies the capacity to sense, actuate and react, all within the material itself.”
Above: Interior view of the Pavillion. Image: achimmenges.net
Key features of the HygroSkin – Meteorosensitive Pavilion:
Biomimetic principle: materially-ingrained responsiveness
Moisture-driven plant movements, unlike other movements produced by cell pressure changes, take place through a passive response to humidity change. This ability of a substance to take in moisture from the atmosphere when dry and yield moisture to the atmosphere when wet is called ‘hygroscopicity’, which allows a material’s moisture content to be in equilibrium with the surrounding relative humidity without any sensory systems or motor functions.
“In this way, the movement is rooted in the material’s intrinsic capacity to interact with the external environment, and it shows how a structured tissue can passively respond to environmental stimuli,” say the architects. Instead of measuring and responding, the Pavilion is designed to let the materials respond themselves.
Development: humidity-responsive wood composites
The design of the Pavilion was developed over several years with a dominating brief — it must utilise materials that do not require any sensory equipment, motor functions or operational energy input. Research eventually enabled the use of wood, one of the oldest and most common construction materials, as a climate-responsive, natural composite.
“Wood’s anisotropic dimensional behaviour was exploited in the development of a humidity responsive veneer-composite element based on simple quarter-cut maple veneer,” explain the architects.
“In the process of adsorption and desorption of moisture triggered by ambient humidity, the distance between the microfibrils in the wood cell tissue changes, resulting in a significant anisotropic change in dimension. Through a precise morphological articulation, this dimensional change can be employed to trigger the shape change of a responsive element.”
Technical development: elastically self-forming and robotically fabricated modular construction
The computational elements of the Pavilion are reliant on the elastically self-forming behaviour of the building’s materials:
“The computational process integrates the material’s capacity to physically compute form in the elastic bending process, the cumulative structure of the resulting building components, the computational detailing of all joints and the generation of the required machine code for the fabrication with a 7-axis industrial robot.
Each component consists of a double layered skin, which initially self-forms as conical surfaces and is subsequently joined to produce a sandwich-panel by vacuum pressing. Final form definition on the modular panels, to precise tolerance levels, is achieved through robotic trimming. The structural capacity of the elastically bent skin surfaces allows for a lightweight, yet robust system, constructed from very thin plywood components.”
Achim Menges Architect, Frankfurt Achim Menges, Steffen Reichert, Boyan Mihaylov (Project Development, Design Development)
Institute for Computational Design, University of Stuttgart Prof. Achim Menges, Oliver David Krieg, Steffen Reichert, David Correa, Katja Rinderspacher, Tobias Schwinn, Nicola Burggraf, Zachary Christian with Yordan Domuzov, Tobias Finkh, Gergana Hadzhimladenova, Michael Herrick, Vanessa Mayer, Henning Otte, Ivaylo Perianov, Sara Petrova, Philipp Siedler, Xenia Tiefensee, Sascha Vallon, Leyla Yunis (Scientific Development, Detail Development, Robotic Fabrication, Assembly)