- Technische Universität Braunschweig, Institute of Geoecology, Climatology and Environmental Meteorology, Braunschweig, Germany (j.heusinger@tu-braunschweig.de)
Increasing building energy efficiency (BEE) standards in regions where HVAC systems are not prevalent, e.g., most of Europe, can lead to an increase in daytime outdoor heat exposure (Maronga et al. 2022, Heusinger et al. 2023). According to microscale simulation studies with PALM and ENVI-met, retrofitting of old buildings to highly energy efficient standards may increase ambient, near-surface temperatures up to 4 K locally at daytime (Maronga et al. 2022, Heusinger et al. 2023). Increased BEE leads to much lower conductive heat fluxes through building materials, thereby increasing building surface temperatures and sensible heat fluxes during the day. This translates into higher daytime air temperatures, which are especially noticeable in building courtyards, potentially due to lower air exchange compared to street canyons. In this study we analyzed several common heat mitigation measures in their efficacy of remediating the additional ambient heat due to higher BEE. The results demonstrate that only measures that directly target the building surfaces are able to neutralize the daytime heating effect by higher BEE, e.g., building greening. Other common heat mitigation measures such as street trees and sun sails are much less effective in this particular case. The results of these modeling experiments should motivate further observational studies to validate the findings and to get a deeper understanding of the processes involved in counteracting the outdoor heating effects caused by increasing BEE standards.
References:
Heusinger, J., Bruchmann, N., & Weber, S. (2023). Modeling the impacts of building energy efficiency on the thermal microclimate in a midsize German city. Urban Climate, 52. https://doi.org/10.1016/j.uclim.2023.101678
Maronga, B., Winkler, M., & Li, D. (2022). Can Areawide Building Retrofitting Affect the Urban Microclimate? An LES Study for Berlin, Germany. Journal of Applied Meteorology and Climatology, 61(7), 800–817. https://doi.org/10.1175/JAMC-D-21-0216.1
How to cite: Heusinger, J. and Weber, S.: How to counteract increasing daytime ambient heat caused by higher building energy efficiency standards, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-750, https://doi.org/10.5194/icuc12-750, 2025.
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