Heat Stress assessment using an urban microclimate zonal model at the block scale coupled with building models

• Published in: Sustainable cities and society 2025-01, Vol.118, Article 106009
• Main Authors: Barone, Flavia, Merlier, Lucie, Bouquerel, Mathias, Kuznik, Frédéric
• Format: Article
• Language: English
• Subjects: Building energy model; Heat stress; Numerical coupling; Zonal microclimate model
• ISSN: 2210-6707
• DOI: 10.1016/j.scs.2024.106009

This contribution presents a toolchain consisting of a microclimate zonal model (HeatScape) coupled with a building energy model (BEM) and a radiative model developed to characterize the thermal environments within buildings and their immediate surroundings for daily and seasonal heat stress assessments. HeatScape comprises an outdoor mean radiant temperature model, a soil model, and an airflow zonal model (AZM). The phenomena involved in the coupling between HeatScape model and the BEM include convective heat exchanges and heat transfers induced by airflow related to mechanical ventilation, natural ventilation, and infiltration. A case study representing a block of buildings highlights the effects of urban form and thermal surfaces properties on the spatial distribution of the indoor and outdoor climatic variables affecting heat stress. Indoors, heat stress is mostly dependent on the air temperature and a significant positive effect is observed when natural ventilation is activated. Outdoors, the heat stress distribution is strongly correlated to the mean radiant temperature distribution. Even in the absence of direct solar radiation, overheating is observed in narrow airzones between buildings facing each other. •Characterizing urban thermal environment is key for assessing outdoor and indoor heat stress.•Heat stress analysis over a season is relevant to assess overheating impact on health.•A microclimate zonal model coupled to a building energy model is developed to assess heat stress.•The model considers the impact of urban form and buildings on airflow and temperature distribution.•The model allows comparison of urban and building cooling strategies for seasonal heat stress.