Multilayered SiO2/Si3N4 photonic emitter to achieve high-performance all-day radiative cooling
Multilayered SiO2/Si3N4 photonic emitter to achieve high-performance all-day radiative cooling
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DOI：
10.1016/j.solmat.2020.110584
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发表时间：
2020-08-01
影响因子：
6.9
通讯作者：
Zhan, Yaohui
中科院分区：
文献类型：
--
作者：
Ma, Hongchen;Yao, Kaiqiang;Zhan, Yaohui
近年来，辐射冷却受到了广泛的关注，这主要是由于其在没有任何外部能量的情况下将多余的热量从地球物体散发到深空的自发热力学过程。然而，仍然存在挑战，以更好地满足光谱选择性的严格要求，以改善当前未优化的冷却性能，特别是对于多层型辐射冷却器。在这项工作中，我们提出了一个辐射冷却器与七层的SiO2和Si 3 N4优化使用进化算法，这首先有利于利用光阻抗失配的太阳辐射的高反射，其次使宽带发射率仅在大气窗口内的互补声子共振，第三抑制大气窗口外的发射率（不仅是太阳光谱范围）。屋顶连续测量和综合计算共同证明了辐射冷却器的优异性能，例如，在类似于900 W/m2的日光下，8 ℃的测量温度下降和87 W/m2的模拟冷却功率。此外，如果在测试期间暴露于由于高湿度而导致的干燥气候，则可以进一步增强冷却性能。我们的工作为多层辐射冷却器提供了一种替代候选方案，其冷却性能与聚合物冷却器相当，并提供了一种合理的设计方法，利用类似光热设备的结构和材料方面。
Radiative cooling has gained considerable attention recently, mainly due to its spontaneous thermodynamic process of dissipating surplus heat from the terrestrial object to deep space without any external energy. However, challenges still remain to meet better the stringent requirement on spectral selectivity for improving the current unoptimized cooling performance, especially for the multilayer-type radiative coolers. In this work, we proposed a radiative cooler with seven layers of SiO2 and Si3N4 optimized by using the evolutionary algorithm, which firstly facilitates a high reflection of solar irradiation utilizing the optical impedance mismatch, secondly enables a broadband emissivity merely within the atmospheric window by complementary phonon resonances, and thirdly suppresses the emissivity outside the atmospheric window (not only the solar spectral range). The continuous rooftop measurement and the comprehensive calculation collectively demonstrated the excellent capability of the radiative cooler, e.g., a measured temperature drop of 8 degrees C and a simulated cooling power of 87 W/m(2) under the sunlight of similar to 900 W/m(2). Besides, the cooling performance can be further enhanced if exposed to a dry climate due to the high humidity during the test. Our work contributes an alternative candidate to multilayered radiative coolers with cooling performance comparable to the polymer counterparts, and as well as providing a rational design approach exploiting both the structural and material aspects for similar photothermal devices.