The German Pavilion at Expo 2025 Osaka has dedicated its presence to the theme around which the shaping of our future revolves: the circular economy. Circularity is the terminological culmination of the sustainability discussion. It is the fulcrum that enables sustainable economies to leverage the holistic closing of material cycles. The primary objective of a circular economy is one with zero waste in which all consumable goods are returned into the cycle and whose consumption of resources is radically minimized.
Circularity is the leitmotif of the German Pavilion: mutually shaping a circular world is the motto. It is all based on the notion of circularity or – translated into design terms – on the shape of a circle: the Pavilion itself, the visitor experience, the design, the technologies and future visions presented all assume this form.
A circular pavilion
Just one quick glance at the architecture of the German Pavilion consisting of seven round structural elements made of wood conveys the leitmotif of circularity. As a holistic entity, the Pavilion marries nature and technology, biosphere and human-made technosphere into one unique visitor experience. In the draft, two ensembles of cylindrical structural elements framing the curated exhibition area and hospitality area join to merge into a freely accessible green park area.
Not only do buildings and garden interact as one creative design unit, but they mutually enhance each other functionally as well. The Pavilion exemplifies how tomorrow’s architecture and urban development could join sustainability and circularity with aesthetics and lived experiences and how built environments, and nature can interact as integrated closed material cycles in a sustainability-driven society.
The Pavilion as an exhibit of circular building
We need to rethink the way in which we design, produce and operate our built environment; but above all, how we post-use or repurpose it. Therein lies enormous and unharnessed potential to help us achieve our sustainability goals. Our intention must be to integrate biosphere and technosphere, the design of built environments whilst reflecting a full awareness of the multiple interdependencies and reciprocal interactions between biological and technical cycles.
With this in mind, the German Pavilion at Expo 2025 Osaka is designed to serve as an example in myriad ways. It consists of a completely circular structure, embedded in the functional landscape in the form of a park. The Pavilion’s distinguishing features include an intelligent indoor climate design and innovative circular construction materials and minimal use of materials that are 100% reusable or recyclable. As such, the German Pavilion at Expo 2025 Osaka is an exponent for circular and sustainable building in its own right.
Ecological and sustainable construction principles for the German Pavilion
In line with the guiding principle and motto of circularity, the building itself is the largest exhibit of the German contribution to the Expo 2025 Osaka and will offer a tangible example of circular and sustainable construction. Every design decision is committed to the goal of creating a building that is as sustainable as possible, while applying the principles of circular construction and making them tangible.
The building combines principles of sustainable construction with those of circular construction, taking into account the entire life cycle of all materials and components used, from manufacture and construction to operation and reuse or recycling, and minimizing the carbon footprint through design decisions and construction processes as far as possible.
Of particular importance here is the holistic view of the building in connection with nature and the diverse material and substance cycles. Together with the surrounding landscape, the building becomes a tangible example of how the man-made technosphere, and the natural biosphere can be conceived in an integrated way. The landscape in the pavilion is not only a natural space that can be experienced, but also follows the principle of biophilic design and combines high-performance aspects. Although these approaches are rather exemplary given the size of the building, the building and landscape are connected in many ways within the cycles.
The building’s cubic volume and the use of passive strategies play a key role in maximizing efficiency and sustainability. The choice of materials is exemplary, with the entire life cycle being taken into account from the outset. Pre-fabricated and standardized components not only facilitate the construction process but also enable easy reuse. The concept of ‘design for disassembly’ is at the forefront: through minimal intervention in components and the reduction of modifications, the building elements are designed to remain largely generic and easy to reuse. Joints between components are minimal and designed to be easily detached.
The building is intended as a snapshot within the lifespan of the materials and components used, with reuse already taken into account in the design. Careful use of resources is reflected in the conscious decision not to use cladding or permanent connections, so that the building can be completely dismantled after the Expo. The components can either be reused in their current form, or the materials can be returned to appropriate material cycles.
The circular floor plan of the pavilion as a symbol and sign of circularity
The architecture of the pavilion conveys its theme and message – circular economy is possible – in a simple and memorable way, creating a poetic and iconographic architecture. The intertwining of park and building, nature and technology, symbolizes the essential objective of the circular economy: a harmonious coexistence of the biosphere and technosphere is necessary – and possible. The pavilion consists of a base with a wedge-shaped geometry that orients itself toward the surrounding ring of the master plan, and two groups of cylindrical structures arranged on this base.
The base integrates the back-of-house (BOH) areas, which are invisible to visitors, and its upper side provides visitors with a view of the entire property. Cylinders are arranged on this base to house the exhibition, restaurant, and lounge. The two ensembles of cylinders are connected by the open event area. This opens onto the front of the site, is accessible separately, and can be seen from the queue.
Use of sustainable building materials
The choice of materials for the German Pavilion is exemplary for sustainable and circular construction. The base stands on a slim foundation with minimal superstructure made of prefabricated steel components that can be reused. The base structure itself consists of prefabricated modular steel elements taken from an existing standardized steel construction system, which can be dismantled after the Expo and reused in any form.
Here, too, the choice of material and construction method are to be understood as examples. Modular construction and the use of standardized and prefabricated components enable reuse and are a core principle of circular construction. In terms of materials, steel is the most circular material in the world – over 90% of the steel ever produced is still in use.
The cylinders are constructed as wooden frame structures. Wood is a renewable raw material that also serves as a carbon store. The wooden elements are generic and digitally prefabricated and designed according to the principle of ‘design for disassembly’ – after the Expo, the supports and beams can be dismantled and reused in a new configuration.
The cylinder framework is filled with prefabricated panels. The materials used are exemplary for sustainable and circular construction and at the same time illustrate the use of traditional rediscovered materials and new findings from materials science: We use clay as an example of a traditional, rediscovered construction method, hemp panels as an example of German industrial products, and panels made from mushroom mycelium as an example of newly developed materials from research.
The landscape is also intended to be exemplary – the planting is being carried out in collaboration with a local tree nursery with centuries of tradition in the Osaka area. The German Pavilion will become a temporary extension of the tree nursery: trees and plants will be temporarily brought from the nursery in northern Osaka to the German Pavilion site and returned to the nursery for reuse after the Expo.
