Integration of Radiative Roof Cooling Coating into Buildings as a Zero-Energy Cool Roof Strategy in Hot and Humid Region

Radiative sky cooling has attracted worldwide attention due to its passive cooling potential with zero energy input. Daytime cooling materials with outstanding spectral properties are developing rapidly. Using these new cooling materials as roof coatings can become one of the most prominent radiative cooling methods integrated with buildings. Current existing models and numerical tools are not able to incorporate the spectral selectivity of radiative cooling materials and local precipitable water vapor, thus failing to accurately predict roof thermal performance. Therefore, we newly develops a spectral selectivity-based passive radiative roof cooling model to integrate full spectral properties of emerging cooling materials and consider precipitable water vapor-induced atmospheric radiation for precise evaluation of roof cooling performance. A field experiment was carried out to validate the developed model. The new spectral selectivity-based radiative roof cooling model can be widely employed to accurately evaluate the utilization of daytime radiative coolers as a rooftop strategy in improving building thermal and energy performance. The energy consumption assessment of buildings with radiative roof cooling coating as a zero-energy cool rooftop strategy in hot and humid region, such as Hong Kong, is conducted. Findings can help local policy makers implement cool roof scheme into low-energy building strategy.