The Impact of Pavement Albedo on Radiative Forcing and Building Energy Demand: Comparative Analysis of Urban Neighborhoods

Abstract

Albedo is the measure of the ratio of solar radiation reflected by the Earth’s surface. High-albedo reflective surfaces absorb less energy and reflect more shortwave radiation. The change in radiative energy balance at the top-of-atmosphere (TOA), which is called radiative forcing (RF), reduces nearby air temperatures and influences the surrounding building energy demand (BED). The impact of reflective surfaces on RF and BED has been investigated separately by researchers through modeling and observational studies, however, no one has compared RF and BED impacts under the same context and the net effect of these two phenomena remains unclear. This paper presents a comprehensive approach to assess the net impacts of pavement albedo modification strategies in selected urban neighborhoods. We apply an adapted analytical model for RF and a hybrid model framework combining two different models for BED to estimate the impacts of increasing pavement albedo from 0.1 to 0.3 for different urban neighborhoods in Boston and Phoenix. The impact of several context-specific factors, including location, urban morphology, shadings etc., are taken into account in the models. Comparative analysis reveals that the net impact of changing pavement albedo can vary from one neighborhood to another. In Phoenix downtown, reflective pavements create net global warming potential burdens, while increasing pavement albedo results in potential savings in the Boston downtown area. This work provides insights into pavement albedo impacts at urban scale and supports more informed decisions on pavement designs that save energy and counteract some of the effects of global warming.