The air is full of water. The world is turning into a desert. Soon, the moisture-farming life of rural Tatooine will be a reality. In some places, it already is.
Anyone who’s ever owned an air conditioner knows that they produce a lot of water when they’re running. Most are designed to evaporate this water. Whole-house AC units often route their condensation into rain gutters or drains. (So wasteful!)
This water comes from condensation. The air is full of water. Based on the air pressure and temperature, there is a point called the dew point which determines how much water the air can hold. If the temperature or pressure change then the dew point changes, and the air will drop some of the water if the dew point moves down. Hence, dew.
This is why many surfaces are coated with water in the morning. As the temperature rises, the water evaporates back into the air. But what if it was possible to collect that water instead of letting it evaporate?
DIY Air Well Designs
Air wells are a whole family of ancient and modern inventions which extract that water from the air before it can evaporate, especially in the early hours of the morning.
Warka Water Towers are one example of a modern air well design. They use a mesh fabric to collect condensation and route it into a reservoir where people can use it for drinking or other purposes. One of these small and lightweight structures can extract up to 100 liters of water per day from thin air.
There are lots of other modern examples of simple and effective air wells like SOURCE Hydropanels which collect up to sixty liters of water every day and they power themselves from the sun.
Here’s another simple DIY air well being developed in the Negev Desert. The argument is so simple; this person simply wrapped saran wrap around two poles that support a sign. Water condenses onto the saran wrap in the morning and drops down to a reservoir.
Imagine all the ways you could stretch mesh or vinyl between things to collect that morning condensation!
The way the Warka Tower creates a cascade to speed up the process is really interesting. It reminds me of the way a marx impulse generator works. I think you could probably build a much larger structure which collects a lot more water in the same way. This seems like the perfect thing to put on the roof of an earthship so that the rain catchment system that’s already in place would also be able to catch dew on the many mornings without rain.