EAGER: Collaborative Research: Cold vapor generation beyond the input solar energy limit and its condensation using thermal radiation

EAGER：合作研究：超出输入太阳能限制的冷蒸汽生成及其利用热辐射的冷凝

• 批准号: 1932843
• 负责人: Zongfu Yu
• 金额: $ 5万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1932843&HistoricalAwards=false
• 关键词: EAGER; Collaborative; Research; Cold; vapor

In recent years, significant interest has developed in using sunlight for electricity-free vapor generation due to its potential to address limitations in fresh water availability around the globe. However, conventional techniques for generating vapor from solar energy typically rely on costly and cumbersome optical concentration systems to enable bulk heating of a liquid, resulting in relatively low efficiencies. This project explores a new way to use solar energy to generate vapor below room temperature ("cold vapor") for solar and thermal energy management applications. Importantly, the interdisciplinary nature of this project provides an excellent educational opportunity for Electrical Engineering and Materials Science curriculum development, integrated outreach activities and student training of the next generation researchers and educators.This project considers a new process of solar vapor generation, i.e., when the evaporation temperature is lower than the room temperature. In this case, the system does not lose energy through conventional conduction, convection and radiation loss channels. Instead, the environment provides additional thermal energy for vapor generation, resulting in a total vaporization rate higher than the upper limit that can be produced using the input solar energy alone. Therefore, the total vapor generation rate can surpass the upper limit set by the input solar energy. This is the major research aim to be studied in this project: i.e. how to realize cold vapor generation below room temperature under regular sun illumination. Additionally, this project also explores moisture condensation at temperatures below ambient using radiative cooling technologies. In pursuit of these goals, this project identifies two major objectives: the first is to explore the fundamental properties of a cold solar-vapor generation system under different solar illumination conditions. The second objective is to explore the possibility of moisture condensation in a cold environment using radiative cooling technologies. The proposed research will offer a novel direction to explore and develop different water evaporation strategies, which may have applications in solar still technology, evaporative cooling and solar evaporated mining applications, evaporation-driven generators and recently reported water-evaporation-induced electricity.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

近年来，由于其解决地球仪周围淡水可用性的限制的潜力，对使用太阳光进行无电蒸汽产生了显著的兴趣。然而，用于从太阳能产生蒸汽的常规技术通常依赖于昂贵且笨重的光学聚集系统来实现液体的整体加热，从而导致相对低的效率。该项目探索了一种新的方法，利用太阳能产生低于室温的蒸汽（“冷蒸汽”），用于太阳能和热能管理应用。重要的是，该项目的跨学科性质为电气工程和材料科学课程开发，综合推广活动和下一代研究人员和教育工作者的学生培训提供了极好的教育机会。当蒸发温度低于室温时，在这种情况下，系统不会通过传统的传导、对流和辐射损失通道损失能量。相反，环境提供额外的热能用于蒸汽生成，导致总蒸发速率高于仅使用输入太阳能可以产生的上限。因此，总的蒸汽产生速率可以超过由输入太阳能设定的上限。这是本项目的主要研究目标：即如何在正常的太阳光照下实现室温以下的冷蒸汽发生。此外，该项目还探索了使用辐射冷却技术在低于环境温度下的水分冷凝。为了实现这些目标，本项目确定了两个主要目标：第一个是探索在不同太阳光照条件下冷太阳能蒸汽发生系统的基本特性。第二个目标是探索在寒冷的环境中使用辐射冷却技术的水分冷凝的可能性。拟议的研究将为探索和开发不同的水蒸发策略提供一个新的方向，这些策略可能在太阳能蒸馏技术、蒸发冷却和太阳能蒸发采矿应用中有应用，蒸发驱动的发电机和最近报道的水蒸发-该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的评估支持影响审查标准。

项目成果

Vapor condensation with daytime radiative cooling

• DOI: 10.1073/pnas.2019292118
• 发表时间: 2021-03
• 期刊: Proceedings of the National Academy of Sciences
• 作者: Ming Zhou;Haomin Song;Xingyu Xu;A. Shahsafi;Yurui Qu;Zhenyang Xia;Z. Ma;M. Kats;Jia Zhu