Xiangwei Sun

Yes, there is a technique for harvesting atmospheric water that does not require an external energy source and can be accomplished using gravity alone. One of the most well-known methods is condensation. This technique utilizes temperature differences between day and night or between cold and warm surfaces to condense moisture from the air.

Principle of operation: Atmospheric moisture can be collected through condensation using passive systems, such as devices that use cold surfaces to collect water from humid air. When humid air comes into contact with a cold surface, the temperature on that surface drops below the dew point, causing water vapor to condense into liquid. This process can occur without any external energy input, using only temperature changes and gravity.

Examples of passive systems:

These systems do not require an external energy source (such as pumps or compressors) and can be very effective in areas with high humidity. All these processes rely on gravity to collect the condensed water, making them energy-efficient and environmentally friendly.

Thank you most sincerely.

Researchers have developed a passive atmospheric water harvesting system that uses gravity-driven droplet flow and radiative cooling. This system operates without energy input, relying on a lubricant-coated surface and a vertical architecture to collect water.