Heat exposure during a power outage: A simulation study of residences across the metro Phoenix area

In the wake of growing concern for climate change, heat waves and their potential health effects (McGeehin and Mirabelli, 2001) [37] have become a recurring phenomenon (Beniston, 2004; Fouillet et al., 2006) [8,21]. Extreme heat events in the USA are responsible for more deaths as compared to other weather events such as hurricanes, lightning, tornadoes and floods (Luber and McGeehin, 2008) [33]. Heat exposure in buildings has risen due to global warming in conjunction with other factors like urbanization and associated heat island effects (Kolokotroni et al., 2012) [25], lack of thermal mass (Lomas and Porritt, 2017a) [31], exposure to solar insolation on higher stories, absence of window shading, overcrowding and envelope properties exacerbate the overheating inside the dwellings (Vellei et al., 2017). [45]. Stone et al. (2021) [43] provides a macro view of the indoor environments in buildings due to the concurrent event of power outage during heat wave in face of climate change. This paper builds on the previous publication and provides a detailed view of modeling methodology, building physics that explains the sources/sinks of heat and entails a detailed evaluation of the current building stock for the low to moderate income residences in the city of Phoenix, Arizona in terms of their thermal performance. Finite Element models of building stock were simulated using MATLAB for microclimate weather files of Phoenix generated by Weather Research and Forecasting (WRF) simulation. Significant differences in temperature were noted in same building archetypes in different pockets of the city indicating the role of urbanization in aggravating the impact of heat wave. Dwellings with high thermal mass are found to be much more resilient to high ambient temperatures as compared to code compliant residences with basements being the coolest zones in all prototypes.