Development of microclimate modeling for enhancing neighborhood thermal performance through urban greenery cover Mohamed Dardir a,b , Umberto Berardi a,⇑ a Department of Architectural Science, Ryerson University, Toronto, ON M5B 2K3, Canada b Department of Architectural Engineering, Ain Shams University, Cairo, Egypt article info Article history: Received 5 April 2021 Revised 29 July 2021 Accepted 30 August 2021 Available online 2 September 2021 Keywords: Green infrastructure Outdoor thermal indices Urban greenery Urban climate Urban heat island abstract Green spaces and vegetation cover offer various environmental benefits, including building energy- saving. Enriching the urban vegetation is fundamental in urban heat island (UHI) mitigation policies pro- moted over the last years in many large North American cities. For example, the Greater Toronto Area (GTA) has been promoting significant increases in urban greenery by intensifying the urban trees and green roofs. In this paper, an updated version of the open-source code of the Urban Weather Generator was developed and validated to assess the effect of the increased horizontal and vertical green infrastructure on the microclimatic thermal performance of three urban typologies within the GTA. The updates of the model efficiently estimate the cooling and warming effects of the urban greenery cover on the microclimate thermal environment. The proposed enhancements included intensifying the tree canopy and incorporating the vegetated façades and green roofs. The validation ensured the model’s abil- ity to predict the cooling and warming effects of the green infrastructure. The results confirmed that tree canopy and green façades were the most effective mitigation strategies for reducing the canyon air tem- perature and building energy consumption, respectively. A parametric analysis utilizing a multi-objective algorithm was also designed to evaluate the effectiveness and affordability of the applied strategies. The results showed that the ambient peak air temperature, the outdoor heat stress index, and building energy savings were reduced by up to 4.6  C, 5.4, and 42.4%, respectively. Considering reducing the green infras- tructure cost by 50%, the parametric study resulted in a reduction of up to 3  C, 2.9, and 35.6% in the ambi- ent peak air temperature, the outdoor heat stress index, and building energy savings, respectively. Ó 2021 Elsevier B.V. All rights reserved. 1. Introduction The combined impact of climate change, Urban Heat Island (UHI), and heatwaves on ambient temperature results in intense heat stress for residents and leads to heat-related illness and death [1–3]. The severe impacts of heatwaves are associated with multi- day heat stress, warm nights, and increased relative humidity. The characteristics of the heatwaves are defined regionally according to the local climatic conditions. For example, Health Canada [4] issues heat warnings when the local weather of Southern Ontario is fore- casted as  31  C for daytime maximum temperature,  20  C for night-time minimum temperature, or 40 or more for the temperature-humidity index (humidex) for two consecutive days. If the conditions are forecasted to continue for three or more days, an extended heat warning is issued. In the last 20 years, 60 heat warnings and 37 extended heat warnings were issued for the Greater Toronto Area (GTA) region [5,6]. Moreover, days with a maximum temperature above 30  C are expected to increase in the GTA from 20 days/year in 2010 to 66 days/year in 2050 [7]. Given the large transformation and fast-growing population of the GTA, and the expected impacts of climate change, it is crucial to investigate the urban design influ- ences on urban dwellers’ heat responses. Moreover, applying heat mitigation strategies that improve the urban environment is essen- tial in the strategic planning for new and existing urban settle- ments [8,9]. The impacts of green infrastructure and increasing vegetation areas were discussed in the literature on meteorological and environmental variables and human thermal comfort [10]. The major cooling effect of the urban green infrastructure is due to the fraction of the blocked solar radiation that reaches the urban surfaces. Accordingly, the selection of the trees’ species should be carefully considered as the leaf density and branching structure significantly influences the shading ability of the trees [11,12]. The impermeable urban surfaces, like asphalt and concrete, https://doi.org/10.1016/j.enbuild.2021.111428 0378-7788/Ó 2021 Elsevier B.V. All rights reserved. ⇑ Corresponding author. E-mail address: uberardi@ryerson.ca (U. Berardi). Energy & Buildings 252 (2021) 111428 Contents lists available at ScienceDirect Energy & Buildings journal homepage: www.elsevier.com/locate/enb