Carlosena Remírez, LauraRuiz-Pardo, ÁlvaroFeng, JieIrulegi, OlatzHernández-Minguillón, Rufino J.Santamouris, Mattheos2023-11-142023-11-142020Carlosena, L., Ruiz-Pardo, Á., Feng, J., Irulegi, O., Hernández-Minguillón, R. J., Santamouris, M. (2020) On the energy potential of daytime radiative cooling for urban heat island mitigation. Solar Energy, 208, 430-444. https://doi.org/10.1016/j.solener.2020.08.015.0038-092X10.1016/j.solener.2020.08.015https://academica-e.unavarra.es/handle/2454/46754The objective of this paper is to present the potential of daytime radiative cooling materials as a strategy to mitigate the Urban Heat Island effect. To evaluate the cooling potential of daytime radiative cooling materials, 15 theoretical materials and seven existing materials were simulated: two radiative cooling materials, a coolmaterial, two white paints, a thermochromic paint and a construction material. The novelty of this study is that it shows that the optimal spectral characteristics of radiative cooling materials depending on the climate conditions and the type of application. A sensitivity analysis was performed to evaluate the impact of each wavelength emissivity on the ability to achieve sub-ambient radiative cooling. The sensitivity analysis comprised a total of 90 theoretical materials with 15 different wavelength combinations and 6 emissivity values. The heat transfer model, which includes conduction, convection, and radiation, was developed using a spectrally-selective sky model. Two conditions were considered: a very conductive surface and a highly insulated one. All the materials were simulated in two cities that suffer from the Urban Heat Island effect—Phoenix and Sydney. The mean surface temperature reduction achieved was 5.30 ◦C in Phoenix and 4.21 ◦C in Sydney. The results presented suggest that the type of application (active or passive) is a determinant factor in the design of radiative cooling materials. Modifying the spectra of the materials led to a substantial change in the cooling potential. A material that performs well in a dry climate as a passive solution could perform poorly as an active solution.application/pdfapplication/mswordeng© 2020 International Solar Energy Society. Published by Elsevier Ltd. This manuscript version is made available under the CC-BY-NC-ND 4.0Daytime radiative coolingSensitivity analysisSpectrally selective materialsCooling potentialUrban Heat Islandinfo:eu-repo/semantics/article2023-11-14info:eu-repo/semantics/openAccess