Advancing Radiative Cooling Materials: A Comprehensive Assessment through Experimental Characterization and Advanced Numerical Heat Transfer Simulations

Using radiative cooling (RC) materials as the outer layer of building components can mitigate the Urban Heat Island (UHI) effect and achieve substantial energy savings. Our research is centred on investigating aluminium- (A) and Vikuiti- (V) based materials for selective and broadband passive radiative cooling in urban settings. These materials possess unique thermo-optical properties compared to a pure aluminium sample (reference), as they reflect most of the incoming solar radiation while efficiently releasing absorbed heat through the atmospheric window (8-13 µm). Through a comprehensive experimental characterization, we have developed and validated a numerical model to evaluate the performance of these materials in typical summer and winter conditions. Our results indicate that materials with enhanced spectral properties, such as the V-based prototype examined in this study, exhibit increased heat exchange with outer space through the atmospheric window, leading to sub-ambient surface temperatures. This innovative approach enables accurate prediction of the radiative cooling capabilities of the samples across diverse climates, offering a promising alternative to current outdoor tests that face challenges in reproducibility and comparisons. This research contributes to advancing passive radiative cooling technologies and provides valuable insights for sustainable urban development.