Microdroplet Intaking Spinning Turbine for Active Radiation Fog Harvesting

Area of Science:

• Environmental Engineering
• Materials Science
• Fluid Dynamics

Background:

• Atmospheric fog harvesting offers a sustainable freshwater source.
• Efficient collection from low-wind, small-droplet fogs is hindered by low droplet inertia.

Purpose of the Study:

• To develop and demonstrate a bioinspired active fog collector for enhanced water harvesting.
• To overcome limitations of passive fog collectors in low-wind environments.

Main Methods:

• Designed the microdroplet intaking spinning turbine (MIST) with rotating samara-like blades.
• Incorporated biomimetic cactus spines for enhanced inertial capture and drip-tip structures for efficient drainage.
• Actively manipulated airflow to create a low-pressure zone, increasing fog flux.

Main Results:

• MIST increased incident fog flux by 5.8-fold.
• Achieved collection efficiencies of 13.8 L m^-2 h^-1 (field) and 96.8 L m^-2 h^-1 (wind tunnel).
• Demonstrated specific energy efficiency of 86 L kWh^-1, outperforming conventional dehumidifiers.

Conclusions:

• The bioinspired MIST architecture significantly enhances fog collection efficiency across diverse mist conditions, especially under low wind.
• MIST shows broad applicability for defogging, outdoor fog harvesting, and viscous oil fume collection.
• This active collection method provides a sustainable solution for freshwater generation.