How to design a resilient building? Lessons learnt from an architectural view

The EIA EBC Annex 80 Resilient Cooling program has focused on bringing together and extending the knowledge on the resilience of buildings to overheating (Holzer, 2024).  In the context of the Annex 80 Resilient Cooling program a research project, Recover++, has been setup to define a new resilience indicator, based on the properties and behaviour of real-world building projects under extreme climatological condition and shocks, as heatwaves under current and future weather conditions. These extreme weather conditions will become a reality for the building stock in the near future. The real impact will depend upon the RCP-scenario. As the mean life expectance of buildings in Europe is between 50 and 60 years, the building stock, which is being designed and built now, will be exposed to these future weather conditions, during its lifespan. And, as the main architectural design features such as the building envelope and the spatial concepts, are less prone to change during the lifetime of a building, it’s relevant to take the impact of these future weather conditions in account, in the architectural design and conception of new buildings. Future weather conditions to which buildings will be exposed, can be both represented by Typical Meteorological Years (TMY), by Extreme Warm and Extreme Cold Years (EWY and ECY), and by weather data which include extreme events as heatwaves (Machard, 2024).  
Up until now the impact of the architectural building features under future weather conditions have mainly been evaluated under typical future weather conditions (TMY, EWY and ECY) (Declercq, 2021, Machard, 2021, Ramon, 2023). These studies have suggested architectural strategies to reduce operational energy use for cooling under future climate conditions (Declercq, 2021 and Machard, 2021) and to reduce the embodied impacts over the full life cycle (Ramon, 2023). In this paper, parameters related to the architectural building properties have been explored which have an impact on the resilience of buildings under extreme weather conditions with shocks, such as heatwaves.  
In this context two real-life buildings of different typology, from which one is under construction and the second one is due for construction, have been modelled and simulated under future weather conditions, including future weather conditions with shocks. Several architectural building features such as thermal mass, natural ventilative cooling strategies and different mechanical cooling strategies have been analysed.  
The conclusions of (Machard, 2021 and Ramon, 2023) have been challenged towards the criteria of resilience to overheating. The case studies have confirmed that the main architectural drivers, influencing the resilience to overheating under extreme conditions, are the glazing ratio, the presence of shading, the thermal mass and the natural ventilative cooling. The design of one of the case studies was evaluated under typical future weather conditions (TMY 2070-2100 under RCP 8,5) (Declercq, 2021). This research has confirmed that the architectural design strategies, which were adopted to reduce the operational energy use for cooling under current and future climate conditions, also result in a high resilience to overheating of the building.