Exploring the effects of rooftop mitigation strategies on 1 urban
temperatures and energy consumption
Abstract
This paper describes and evaluates novel parameterizations for
accounting for the effect of rooftop mitigation strategies on the urban
environment, in the context of the mesoscale model Weather Research and
Forecasting (WRF), coupled with a urban canopy parameterization and a
building energy model (BEP+BEM). Through the new implementation, the
sensitivity of near-surface air temperature and building energy
consumption to different rooftop mitigation strategies is evaluated by
means of numerical simulations in idealized urban areas, for typical
summer and winter conditions. Rooftop mitigation strategies considered
include cool roofs, green roofs and rooftop photovoltaic panels. Results
indicate that near-surface air temperature is reduced by all the RMSs
during the summer period: cool roofs are the most efficient in
decreasing air temperature (up to 1 °C on average), followed by green
roofs and photovoltaic panels. Green roofs reveal to be the most
efficient strategy in reducing the energy consumption by air
conditioning systems, up to 45%, while electricity produced by
photovoltaic panels overcomes energy demand by air conditioning systems.
During wintertime, green roofs maintain a higher near-surface air
temperature than standard roofs. On the other hand, photovoltaic panels
and cool roofs reduce near-surface air temperature, resulting in a
reduced thermal comfort. The results presented here show that the novel
parameterization schemes implemented in the WRF model can be a valuable
tool to evaluate the effects of mitigation strategies in the urban
environment. The new model is available as part of the public release of
WRF in version 4.3.