Co-Innovation Center of Efficient Processing and Utilization of Forest Resource, School of Materials Science and Engineering, Nanjing Forestry University, Nanjing, Jiangsu 210037, China.
Sustainable Materials and Chemistry, Department of Wood Technology and Wood-based Composites, Georg-August-University of Göttingen, Büsgenweg 4, Göttingen 37077, Germany.
Nano Lett. 2022 May 25;22(10):4106-4114. doi: 10.1021/acs.nanolett.2c00844. Epub 2022 May 5.
A passive cooling strategy without any electricity input has shown a significant impact on overall energy consumption globally. However, designing tunable daytime radiative cooler to meet requirement of different weather conditions is still a big challenge, especially in hot, humid regions. Here, a novel type of tunable, thermally insulating and compressible cellulose nanocrystal (CNC) aerogel coolers is prepared via chemical cross-linking and unidirectional freeze casting process. Such aerogel coolers can achieve a subambient temperature drop of 9.2 °C under direct sunlight and promisingly reached the reduction of ∼7.4 °C even in hot, moist, and fickle extreme surroundings. The tunable cooling performance can be realized via controlling the compression ratio of shape-malleable aerogel coolers. Furthermore, energy consumption modeling of using such aerogel coolers in buildings in China shows 35.4% reduction of cooling energy. This work can pave the way toward designing high-performance, thermal-regulating materials for energy consumption savings.
一种无需任何电力输入的被动冷却策略已经对全球的总能源消耗产生了重大影响。然而，设计可调谐的日间辐射冷却器以满足不同天气条件的要求仍然是一个巨大的挑战，特别是在炎热、潮湿的地区。在这里，通过化学交联和单向冷冻铸造工艺制备了一种新型可调谐、绝热且可压缩的纤维素纳米晶体（CNC）气凝胶冷却器。这种气凝胶冷却器可以在阳光直射下实现低于环境温度 9.2°C 的温度下降，并且有望在炎热、潮湿和多变的极端环境中达到约 7.4°C 的降温。通过控制形状可塑的气凝胶冷却器的压缩比，可以实现可调谐的冷却性能。此外，在中国建筑物中使用这种气凝胶冷却器的能耗建模表明，冷却能耗降低了 35.4%。这项工作为设计用于节能的高性能热调节材料铺平了道路。
