Harvesting Water and Energy from the Air: Developing a Fog-based Self-powered System (FSS) for Efficient Fog Harvesting

Project: Research

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Freshwater is one of the most important natural resources for human activities and the demand for clean freshwater is enormous for many areas around the globe. However, the threat that water security poses to human populations is rapidly becoming a significant global issue that is presently affecting more than 1.1 billion people. Considering this, finding a promising means to overcome the water security is an urgent task for many countries. Fog harvesting is a typical capture scheme for atmospheric water and enables rapid on-site freshwater production. Most importantly, it is a promising approach for potable water production, without requiring long-distance or ultra-long-distance transport or massive energy consumption. This proposal seeks to develop an innovative fog-based self-powered system (FSS) that captures water and energy from the air. Our preliminary lab-scale demonstrations not only set a world record of the high-power droplet-based output, but also, most importantly, open new windows for using FSS system to produce onsite freshwater from the air, and power remote electrical appliances and subsequently realize the 'off-the-grid' concept. The zero-emission characteristic of the FSS system is also perfectly in line with the global goal of carbon neutrality by 2050. Through this project, we attempt to adopt three new ‘droplet’-based approaches in order to increase the fog-harvesting rate for our benchmark FSS. The fog-collection efficiency is correlated with the dynamic interaction of droplets with solid surfaces. Understanding the fundamental mechanisms of the proposed enhancement approaches with respect to droplet dynamics will be the prioritized task of this project. In particular, the impacts of (1) electrical forces, (2) capillary cooling, and (3) vibration on droplet dynamics and fog harvesting rate will be paid attention to. We will also attempt to design a highly integrated FSS comprising an array of vertical DEGs, each of which can be seen as an independent power source. This simple but vital structure is expected to solve the limited electrical output of the conventional DEG owing to residual charges in sliding droplets. The collected theoretical and experimental results from this project will provide an important design framework for building an integrated FSS that can effectively capture water and energy effectively form the air in the outdoor environment. The acquired knowledge regarding aerodynamics, heat transfer, electronics and material science behind this project will serve as an important knowledge platform for many other applications.


Project number9043553
Grant typeGRF
Effective start/end date1/10/23 → …