How can we effectively renovate millions of buildings to meet climate goals? At the recent HiDALGO2 clustering event, Christophe Prud’homme, Professor at the University of Strasbourg and leader of the Urban Buildings pilot, unveiled a massive-scale simulation framework designed to “Map, Image, Simulate, and Capitalise” urban energy usage.
The building sector is one of the largest contributors to greenhouse gas emissions and energy consumption in Europe. While EU policies demand aggressive renovation strategies, the challenge lies in scale: how do policy-makers and real estate owners prioritise which buildings to renovate first?
The answer lies in the Ktirio Urban Building pilot, a sophisticated solution to complex urban physics that leverages EuroHPC supercomputing to bridge the gap between individual building comfort and city-wide energy planning.
The presentation of Christophe Prud’homme is available here while more technical information on this pilot are available on the dedicated pilot webpage here.
The Ktirio Framework
Ktirio is designed to simulate energy consumption from a single building level up to a city scale and beyond. Its strength lies in its multiscale approach:
– Temporal: Simulations range from minute-by-minute indoor air quality and comfort checks to year-long energy consumption projections.
– Spatial: The tool bridges the gap between regional weather models (1-km resolution) and meter-level microclimate conditions within specific city streets.
– Data-Driven: By utilising open vector databases and OpenMeteo data, the framework can reconstruct urban environments from anywhere in the world, supplemented by satellite and LiDAR data for increased accuracy.
Scaling these simulations to hundreds of thousands of buildings (for entire cities or countries) requires the immense power of EuroHPC systems, such as Deucalion and Leonardo. This high-performance computing (HPC) integration allows experts to perform “what-if” scenarios, predicting how heatwaves, wildfires, or extreme pollution events will affect city energy demands and indoor comfort.
The Ktirio technical workflow is an automated end-to-end pipeline, to deploy its framework from mesh to KPIs:
– Data Selection: Users select an area of interest via a Graphical User Interface (GUI).
– Meshing: The system generates a weather-type mesh using Adaptive Mesh Refinement (AMR), accounting for roads, vegetation, and roof shapes.
– Partitioning: To ensure scalability, the computational load is distributed over thousands of cores.
– Simulation: The engine computes dynamic energy usage, solar masks (how buildings interact with sunlight), and indoor air pollution.
– Output: Automated reports provide urban planners with visualisations on key performance indicators (KPIs) regarding energy efficiency and occupant comfort.
The team has already presented evidence of the correctness of their results based on known benchmarks as well as sensors inside buidlngs to check their work.
Future Horizons and Industrial Readiness
The transition from a research pilot to a functional platform is already underway, with a strategic roadmap targeting full industrial readiness by 2026. Key milestones include:
– Broadening Access: By late March 2026, the team plans to provide external access to the platform for engineering company partners and interested cities through a configured Keycloak environment.
– Commercial Strategy: The team is currently in the contract phase with industrial partners to define commercial licensing and subscription-based service models provided by Cemosis or the University of Strasbourg.
– Scaling Impact: Building on the current TRL 7 foundation, future work will focus on reaching TRL 9, supported by technical contributions for the PPIM 2026 conference.
– Enhanced Visualisation: Future updates will integrate the full workflow within a single GUI, moving beyond specialised tools like ParaView to provide user-oriented dashboards that allow planners to “walk” through simulated districts and view real-time statistics.
By providing a “fair”, data-driven way to prioritise budgets, the Urban Building pilot (Ktirio) ensures that renovation is governed by impact, rather than qualitative estimations and whoever has the loudest voice in policy discussions.
Ηοwever as the pilot leader Christophe Prud’Homme explains,
“Simulation doesn’t replace site expertise — experts are very important; they are essential because by using the tool, they can target the work of an expert and sequence it over time, to decide what is important at the moment.”
About the Authors
This article was curated and designed by the Future Needs team, leading the Outreach, Awareness, and Impact Creation for the HiDALGO2 Center of Excellence.
Kyriaki Daskaloudi and Georgia Nikolakopoulou managed the dissemination and exploitation strategy for this pilot. This included coordinating with technical leads to group exploitable results—such as the Ktirio code and the GUI—into cohesive market distribution strategies and business models. The team also organised the HiDALGO2 Clustering Event at the High-Performance Computing Centre Stuttgart (HLRS) and continues to manage the project’s presence at major summits, such as the HPC Summit in Cyprus.
Learn more about HiDALGO2: hidalgo2.eu
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