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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

WAVELENGTH SELECTIVE COVER FOR SUB-AMBIENT PASSIVE RADIATIVE COOLING

Get access (open in a dialog) DOI: 10.1615/IHTC16.rti.023655
pages 8415-8422

要約

Materials that reject heat into Space by selectively radiating through the atmospheric 8-13 μm transparency band show promise in passive cooling applications such as peak electrical load reduction and dry cooling for arid climates. Being able to emit in the 8-13 μm "atmospheric window" while simultaneously preventing solar radiation from reaching the cold emitter is important to the performance of the device. We investigate an approach where selective emission is enabled by a selectively transparent cover on top of a broadband emitter. A theoretical study is conducted on the effects of volume fraction and material composition on the radiative properties of the cover. By tailoring the porosity and composition of the solid structure we observe a spectral region of transmittance surrounded by regions of short-wavelength scattering and long-wavelength absorption. Unlike conventional white paints that primarily reflect sunlight, a selectively transparent porous cover may enable passive cooling at temperatures lower than the surroundings.