Evaluating the effects of green roofs and green façade as an urban heat island adaptation strategy

¹ Laboratory of General and Agricultural Meteorology, Agricultural University of Athens, Iera Odos 75, 11855, Athens, Greece
² Laboratory of Technology and Policy of Energy and the Environment, School of Applied Arts and Sustainable Design, Hellenic Open University, Parodos Aristotelous 18, Patra 26335 – Greece
³ Laboratory of Urban Planning and Architecture, Department of Civil Engineering, School of Engineering, University of West Attica, 250 Thivon & P.Ralli Str., 12241 Athens, Greece

^* Corresponding author: tseliou.areti@ac.eap.gr

Abstract

The present study investigated the potential cooling effect of green roofs and green façades on a residential neighborhood in Athens during a typical summer day. The numerical model ENVI-met was employed to simulate the thermal environment of the study area at the existing configuration. Then, different design interventions focusing on the application of green façade and green roofs on the rooftops of the existing buildings were developed in order to evaluate the potential amelioration of the adverse thermal conditions. Thermal conditions were assessed based on basic meteorological parameter values and well-known thermal indices estimations. Results showed that at a two-floor building rooftop, the thermal conditions improved only slightly. Most importantly, the inclusive green roofs did not configure a significant cooling effect compared to that of low-height vegetation existing in the exclusive green roofs. Finally, results showed that the synergetic effect of green roofs and green façade produced a greater amelioration of thermal comfort conditions, compared to that produced by the green roofs solely. The greatest amelioration of thermal sensation conditions was achieved by the combination of inclusive green roofs and green façade.