

© FDFA, Presence Switzerland
Thermal Governance - EXPO Osaka
Preliminary results of the PhD thesis "Subtropical Vienna" by Julian Raffetseder are currently on display at the World EXPO Osaka 2025. Selected from more than 200 submissions the project is part of the "Planet" exhibition running from August 15 to October 12 in the Swiss Pavilion. The project continues the chairs long term research on "Thermal Governance" highlighting the need for collective responses to the climate crisis.
The PhD project “Subtropical Vienna: Integrating Solar Governance in the Climate Adaptation of a Central European City” investigates how solar governance, the deliberate planning of daylight and shade access in cities, can guide the climate adaptation of compact urban form in Central Europe. Using scenario-based methods, it explores how the built environment can respond to future climate conditions by negotiating solar and shade access in ways that are both spatially and societally meaningful.

© FDFA, Presence Switzerland

© FDFA, Presence Switzerland

© FDFA, Presence Switzerland
The exhibited model shows a climate adaptation scenario for a “Subtropical Vienna” where the access to daylight and shade are carefully balanced. It explores how sunlight and shade can shape a city’s geometry while maintaining daylight access. Color coding reveals the relationship between claims for daylight access (blue) and shade provision (red), and the volumes that result from them. The design scenario is informed by prior stakeholder interviews collecting the sun and shade preferences of local residents.