A <i>Janus</i> emitter for passive heat release from enclosures.

Heo, Se-Yeon; Lee, Gil Ju; Kim, Do Hyeon; Kim, Yeong Jae; Ishii, Satoshi; Kim, Min Seok; Seok, Tae Joon; Lee, Bong Jae et al. · Sci Adv · 2020

basic_science · Level V

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Abstract

Passive radiative cooling functions by reflecting the solar spectrum and emitting infrared waves in broadband or selectively. However, cooling enclosed spaces that trap heat by greenhouse effect remains a challenge. We present a <i>Janus</i> emitter (<i>J</i>ET) consisting of an Ag-polydimethylsiloxane layer on micropatterned quartz substrate. The induced spoof surface plasmon polariton helps overcome inherent emissivity loss of the polymer and creates near-ideal selective and broadband emission on the separate sides. This design results in not only remarkable surface cooling when the <i>J</i>ET is attached with either side facing outwards but also space cooling when used as an enclosure wall. Thus, the <i>J</i>ET can passively mitigate the greenhouse effect in enclosures while offering surface cooling performance comparable to conventional radiative coolers.