IN-24-C001 – Using Urban Building Energy Modeling to Quantify the Energy Saving Potential for Radiative Cooling

Cooling in buildings accounts for nearly 20% of total energy consumption worldwide. Spectrum-selective radiative cooling materials (RCMs) have proven to be one of the most effective passive technologies for reducing building cooling demands and mitigating urban overheating. RCMs can reflect solar radiation and use the universe as a cold sink to dissipate heat from surfaces on Earth. Many studies have focused on assessing the energy-saving potential of RCMs. However, existing studies mainly focus on individual buildings, and the energy-saving potential of RCMs at the urban scale remains unclear. This study integrated a dynamic performance simulation of RCMs and an urban building energy model (UBEM) to assess the energy-saving potential at the urban scale. The integrated approach considered the real geometry of the building stock and shading effects among buildings, which enabled the simulation of cooling consumption at high spatiotemporal resolution. The building stock in downtown Guangzhou, China, was taken as a case study, and the annual total cooling consumption, peak cooling load, and daily load profile were analyzed. The results showed that radiative cooling could reduce the total cooling demand by 17.3% at the urban scale. The total cooling demand was reduced by 31.0% in residential buildings, while the cooling demand in commercial buildings was reduced by 6.2-17.8%. The energy-saving potential for RCMs was found for buildings of several types, although the magnitudes of the potential differed across buildings. The results showed that radiative cooling could significantly reduce cooling energy consumption and the use of active cooling measures. The proposed approach can be used to assess large-scale heat mitigation measures for urban heat islands or heat waves. This modeling framework is adaptable to other regions with sufficient input data. The findings are valuable for city managers and researchers to evaluate technology suitability and develop relevant policies.