Zhang Ji, Zhou Zhihua, Tang Huajie, Xing Jincheng, Quan Jiayou, Liu Junwei, Yu Junrong, Hu Mingke
Tianjin Key Laboratory of Indoor Air Environmental Quality Control, College of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China.
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
ACS Appl Mater Interfaces. 2021 Mar 31;13(12):14132-14140. doi: 10.1021/acsami.0c21204. Epub 2021 Mar 16.
As a passive cooling strategy, radiative cooling is becoming an appealing approach to dissipate heat from terrestrial emitters to the outer space. However, the currently achieved cooling performance is still underperforming due to considerable solar radiation absorbed by the emitter and nonradiative heat transferred from the surroundings. Here, we proposed a mechanically robust and spectrally selective convection shield composed of nanoporous composite fabric (NCF) to achieve daytime subambient radiative cooling. By selectively reflecting ∼95% solar radiation, transmitting ∼84% thermal radiation, and suppressing the nonradiative heat transferred from warmer surroundings, the NCF-based radiative cooler demonstrated an average daytime temperature reduction of ∼4.9 °C below the ambient temperature, resulting in an average net radiative cooling power of ∼48 W/m over a 24 h measurement. In addition, we also modeled the potential cooling capacity of the NCF-based radiative cooler and demonstrated that it can cover the cooling demands of energy-efficient residential buildings in most regions of China. Excellent spectral selectivity, mechanical strength, and weatherability of the NCF cover enable a much broader selection for the emitters, which is promising in the real-world deployment of direct daytime subambient radiative cooling.
作为一种被动冷却策略，辐射冷却正成为一种将热量从地面发射体散发到外层空间的有吸引力的方法。然而，由于发射体吸收大量太阳辐射以及周围环境传递的非辐射热，目前实现的冷却性能仍未达到理想水平。在此，我们提出了一种由纳米多孔复合织物（NCF）组成的机械坚固且光谱选择性的对流屏蔽，以实现白天低于环境温度的辐射冷却。通过选择性地反射约95%的太阳辐射、透射约84%的热辐射，并抑制从较温暖环境传递的非辐射热，基于NCF的辐射冷却器在24小时测量中显示出平均白天温度比环境温度低约4.9°C，从而产生约48 W/m²的平均净辐射冷却功率。此外，我们还对基于NCF的辐射冷却器的潜在冷却能力进行了建模，并证明它可以满足中国大部分地区节能住宅建筑的冷却需求。NCF覆盖层出色的光谱选择性、机械强度和耐候性为发射体提供了更广泛的选择，这在直接白天低于环境温度的辐射冷却的实际应用中具有广阔前景。
