Can Areawide Building Retrofitting Affect the Urban Microclimate? An LES Study for Berlin, Germany

authored by

Björn Maronga, Matthias Winkler, Dan Li

Abstract

In this work, we investigate the effect of areawide building retrofitting on summertime, street-level outdoor temperatures in an urban district in Berlin, Germany. We perform two building-resolving, weeklong large-eddy simula-tions: one with nonretrofitted buildings and the other with retrofitted buildings in the entire domain to meet today’s energy efficiency standards. The comparison of the two simulations reveals that the mean outdoor temperatures are higher with retrofitted buildings during daytime conditions. This behavior is caused by the much smaller inertia of the outermost roof/ wall layer in the retrofitting case, which is thermally decoupled from the inner roof/wall layers by an insulation layer. As a result, the outermost layer heats up more rigorously during the daytime, leading to increased sensible heat fluxes into the atmosphere. During the nighttime, the outermost layer’s temperature drops down faster, resulting in cooling of the atmo-sphere. However, as the simulation progresses, the cooling effect becomes smaller and the warming effect becomes larger. After 1 week, we find the mean temperatures to be 4 K higher during the daytime while the cooling effects become negligible.

Organisation(s)

Institute of Meteorology and Climatology

External Organisation(s)

Fraunhofer Institute for Building Physics (IBP)
Boston University (BU)

Type

Article

Journal

Journal of Applied Meteorology and Climatology

Volume

61

Pages

800-817

No. of pages

18

ISSN

1558-8424

Publication date

07.2022

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Atmospheric Science

Sustainable Development Goals

SDG 7 - Affordable and Clean Energy

Electronic version(s)

https://doi.org/10.1175/JAMC-D-21-0216.1 (Access: Open)