Optimization of Urban Cooling Strategies for Parking Lots in Hot and Dry Climates: Case Study of Las Vegas and Adelaide

Abstract

Urban microclimates are distinguished by the balance between solar gain and heat lost from building envelope and ground surfaces, by convective heat exchange, and by the generation of anthropogenic heat within the city. Global climate change and the urban heat island (UHI) effect—whereby cities are up to 8 °C hotter than their surrounding countryside—carry growing threats to outdoor living, public health, and urban energy demand. Urban heat stress intensifies in cities with hot and dry summer climates such as Las Vegas (USA) and Adelaide (Australia), where the temperature goes frequently above 36 °C (97 °F). Both cities have a dry, hot, and arid climate. Possible adaptation countermeasures include cool surfaces, urban greenery, and active cooling with the consideration of higher demand for water and energy, and potential winter cooling penalties. Large open-air parking lots appear in many modern cities around shopping malls, hospitals and public venues and provide essential access to these public facilities. In this context, a comparative study of different cooling strategies informs more effective decision making for the design and implementation of UHI adaptation and mitigation strategies. This chapter compares urban cooling strategies for typical parking lots in Downtown Las Vegas, Adelaide CBD and the suburban context. Cool surface materials, tree canopy, evaporative cooling and shading scenarios are estimated, and cooling benefits and side effects of each intervention are discussed. The research shows that planting trees between car parking spaces is vital to most urban environments, especially for parking lots where it leads to 1–5 °C summer cooling.