Comparing the energy performance of spectral-dependent radiative cooling materials through building dynamic simulation

Daytime radiative cooling (DRC) is a passive cooling technique that can achieve sub-ambient superficial temperatures under direct sunlight. While its large-scale fabrication has been mainly impeded due to high costs, no real-life case studies have been implemented to evaluate this technique at a building scale. Instead, several modeling studies have been performed to assess the effects of DRC on the thermal environment of buildings. These buildings are designed for various uses and/or located in different climate zones. A majority of these studies report on the application of a specific type of DRC only – be it multilayer DRC, metamaterial DRC, randomly distributed particle DRC, or porous DRC – and these are generally applied to either residential or commercial buildings. Moreover, most of these studies fail to simulate the spectral-dependent emissivity of the tested DRC, instead presuming an average, constant-emissivity value. This study aims to model and compare the application of the 20 existing types of DRCs. We will investigate their application and effects on the thermal environment of buildings with respect to two different applications and climate contexts. This study's outcomes will offer a comprehensive evaluation of DRC performance. This is a fundamental step towards the broader real-life application in the built environment, promising improvements in both energy saving and user thermal comfort. It also lends greater resilience to the built environment.