Case Study: BK City (TU Delft)

After a fire destroyed TU Delft's architecture faculty in 2008, the university faced a choice: rebuild a building, or reimagine what an educational building could be. They chose the second option. Working with Except using SiD, the team transformed a 1920s listed monument into a didactic tool that puts sustainability at the heart of education for generations of architects.

The Setting

The newly chosen building, dubbed BK City, was a magnificent listed monument of more than 30,000 square meters. A historic 1920s labyrinthine brick structure, its contemporary funky furniture and colorful interior designs belied a far less wallet-friendly energy bill. The building housed knowledge. The question was whether it could also impart it.

Except was invited by the Technical University of Delft to design a sustainable vision for the relocated faculty. The team applied SiD with a composition drawn straight from the method's recommendations: an architect, an environmental scientist, an engineer, an ecologist, and a business analyst. Five disciplines. Five ways of seeing the same building.

The Systemic Goal

The project began from a single, powerful idea: the building should not only house knowledge but teach it. While focusing on increasing energy efficiency and decreasing operating costs, the team embraced the refurbishment as an opportunity to increase students' hands-on understanding of sustainability. Every intervention was designed to be participatory, didactic, and engaging, giving students a 21st-century knowledge base they could leverage within and beyond BK City.

The central goal: transform the building into a didactic tool that anticipates and responds to the shifting field of architecture, with an influence that extends beyond its own walls through the actions of those it has educated. BK City is more than a building. It connects the lives of many individuals, functions as a learning platform for generations of architects and urban planners, and acts as the social and functional hub of the disciplines it serves.

This is a system-level goal. It does not say "reduce energy by X percent." It says "create a building that teaches sustainability to every architect who walks through it for the next century." The energy reduction follows naturally from such a goal. So does everything else.

ELSI-Organized Interventions

The team broke the analysis into the components SiD relies on to ensure sustainability is addressed in an integrated manner. Each stream produced specific interventions, and each intervention had cross-cutting benefits across multiple categories.

Energy and Materials. Wall, roof, and window insulation saves 67% of heat loss. "Easy gains" in electrical equipment and lighting. Glass-embedded photovoltaics. A south atrium with Fresnel PV panels and ground storage. Connection to the campus bio-gas combined heat and power system. A compact volume that reduces surface exposure by 32%. And, critically, space reserved for future energy innovations that do not yet exist.

Ecosystems and Species. A pervasive building ecosystem. An enclosed atrium garden called the "Green Lung." A polyculture and monoculture greenhouse. A plant-based climatization system. Water self-sufficiency through bio-based filtering. Green roofs on existing atria. The building does not merely reduce its ecological footprint. It creates ecology.

Culture and Economy. An open-source, participatory framework. A new main entrance and west atrium. Collaborative frameworks with Wageningen University and TU Delft Botanical Gardens. An integrated campus where the technological and ecological meet. Long-term economic stability through reduced operating costs and increased space efficiency.

Health and Happiness. An upgraded heat recapture ventilation system using the existing tower as a driver. A sustainable, healthy, low-energy food system. Relaxation and natural zones. A BK City gym. And the research-backed finding that a natural environment produces a 12% performance gain in cognitive tasks, meaning the green interventions do not merely improve well-being but measurably increase academic output.

The Phased Roadmap

In addition to the four thematic streams, the team created a phased vision that interweaves easy energy gains and immediate solutions with more ambitious systemic interventions. Each phase builds on the one before it. Quick wins fund longer-term investments. Visible changes build support for less visible ones.

The result: a highly didactic building with exemplary environmental quality, an indoor plant ecosystem, more than 10,000 square meters of additional usable space, operationally sustainable energy and water usage, and a total investment of less than 25 million euros over ten years. The building would be energy and carbon neutral within a decade.

Why This Case Matters

BK City demonstrates several SiD principles in action. First, the power of a system-level goal: by aiming at "teaching sustainability through architecture" rather than "reducing emissions," the team discovered interventions that addressed multiple categories simultaneously. Second, the value of ELSI as an organizing framework: breaking the analysis into Energy/Materials, Ecosystems/Species, Culture/Economy, and Health/Happiness ensured no domain was neglected. Third, the importance of phasing: by structuring the roadmap so that each phase enables the next, the project became financially feasible and politically achievable.

Where Merredin failed for lack of stakeholder involvement, BK City succeeded because it was embedded in the institution it served. The building's users (students, faculty, staff) were both the stakeholders and the beneficiaries. The didactic framework meant that the interventions themselves became tools for engagement: every green roof, every atrium garden, every energy display was a teaching moment.