Daytime radiative cooling of enclosed water using spectral selective metamaterial based cooling surfaces

Autor: Yuan Dan, Cao Peng, Jinchao Yuan, Xu Shaoyu, Hongle Yin
Rok vydání: 2020
Předmět:
Zdroj: Energy for Sustainable Development. 57:22-31
ISSN: 0973-0826
DOI: 10.1016/j.esd.2020.04.008
Popis: Recent development in spectral selective metamaterials makes daytime radiative cooling possible by engineering the material surface to achieve high reflectance in the solar irradiation waveband (0.3–2.5 μm) but high emissivity in the 8–13 μm atmospheric window. In this paper, a spectral selective polymer-based metamaterial was applied on top of a shallow aluminum box that contained with an enclosed body of water for daytime radiative cooling. The performance of such a system was compared to a similar bare Aluminum alloys plate; and a similar one with an Aluminum foil covered plate. The water temperatures were continuously measured for the three cases in a 72-hour period. The results showed that the metamaterial can effectively achieve daytime radiative cooling effect and maintain a consistent water temperature below the ambient air temperature for 2–14 °C. In contrast, the water temperatures in the aluminum foil covered plate and the bare aluminum alloy plate were above the ambient for a 10 °C and 15 °C max during the daytime. The radiative cooling power of the metamaterial water plate was also computed to be of 15–100 W/m2 during the daytime. Finally, the validated radiative cooler model was numerically studied for serving as “free cooling” source for a typical single-house building. Properly integrated into a radiant floor hydronic cooling system, the radiative cooler was found to be able to compensate >60% of annual cooling electricity consumptions. The study shed insights on the potential of applying daytime radiative cooling component and systems in buildings as a sustainable design measure to significantly reduce peak cooling load and annual cooling energy consumptions.
Databáze: OpenAIRE
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