There's water around us all the time, we just can't see it. The air in our atmosphere contains a varying amount of water vapor, depending on the weather. When it's hot and humid, evaporated water can make up as much as 6 percent of the air we breathe. On cold, dry days it can be as low as .07 percent of the air's makeup.
This air is part of the water cycle, an Earth process. Crudely put, water evaporates out of rivers, lakes and the ocean. It's carried up into the atmosphere, where it can collect into clouds (which are actually just accumulations of water vapor). After the clouds reach the saturation point, water droplets will form, which we know as rain. This rain runs off the land and collects into bodies of water, where the whole process begins again.
The problem is, the water cycle goes through dry periods. Because of this, some inventors have begun to wonder, why wait? Why not pull the water vapor right out of the air?
Well, some have done just that. Here's a look at some of the latest technologies for creating water out of thin air.
Enrique Veiga, an 82-year-old Spanish engineer, invented a drinking water extractor that uses electricity to cool air until it condenses into water. It's the same effect that causes condensation in air conditioning units.
He's not the first person to use this technology, but his company, Aquaer, is the first to work in temperatures above 104 degrees Fahrenheit (40 degrees Celsius) and humidity as low as between 10 and 15 percent. In other words, his machine can make water in the desert, which happens to be the kind of place where people need water the most.
After perfecting the machine, Aquaer was commissioned to supply drinking water to areas of Namibia and in a refugee camp in Lebanon. Veiga founded a nonprofit, called Water Inception, with a vision to distribute his water-making machines to more refugee camps and other dry parts of the world.
Australian inventor Max Whisson is using another approach. His Whisson Windmill uses wind power to collect water out of the atmosphere. In 2018, he told the Australian Broadcasting Corporation that water vapor amounts to about "10,000 billion litres [about 2,600 billion gallons] in the bottom kilometere [about .62 miles] of air around the world." And all of this water is replaced every few hours as part of the water cycle.
Whisson's windmill uses refrigerant to cool the blades of his mill, which he's named Max Water. These blades are situated vertically rather than diagonally, so that even the slightest breeze turns them. The blades cool the air, causing water vapor to condense and become liquid water again. This condensation is then collected and stored. Whisson's windmill can collect as much as 2,600 gallons (9,842 liters) of water from the air per day.
Whisson said that his biggest challenge isn't the engineering behind his invention but finding the venture capital to back it.
Tsunami Products' Atmospheric Water Generator
Tsunami Products, a Washington-based company operating out of California, has developed a device for creating water that works similarly to an air conditioner. It dehumidifies air, extracts water vapor and then filters it so it's ready for drinking.
According to Tsunami Products, the device works by drawing air "through a series of condensing coils, where water vapor is cooled down sufficiently to reach the dew point. This converts water vapor into droplets." The converted water is then filtered for any contaminants, such as pathogens and pollen, and collected in a storage tank ready for tapping.
The higher the relative humidity, the more water there is in the air to capture. Considering fog occurs when relative humidity is nearly 100 percent, you would think that researchers would try extracting water from fog. And you would be right.
Fog-harvesting machines have been around for years and, as logic would suggest, work best in foggy climates such as coastal and mountainous regions. These relatively low-cost collection systems resemble volleyball nets with a fine mesh like a window screen. The screens capture water when wind blows through. Unfortunately, water droplets can clog the screens, preventing the wind from passing through, thus preventing the device from collecting water.
To improve upon this design, Jonathan Boreyko, who heads up the Nature-inspired Fluids and Interfaces Lab at Virginia Tech, took a cue from Mother Nature. He studied how giant sequoia trees collect water from fog on their needles, which run parallel to the ground. As the water collects on the needles, it then rolls downward and drips onto the ground essentially watering the tree's roots.
Based on this insight, Boreyko's lab designed small, lab-scale fog-harvesting "harps" with horizontal collection wires to simulate giant sequoia needles. This method resulted in a water harvest from fog three times greater than similar-sized systems using vertical wires.
Several companies currently sell water-from-air machines, such as Florida-based Drinkable Air. The company uses "atmospheric water generator technology" to pull air through an electrostatic-antimicrobial filter intended to remove airborne particles. A condensation unit receives the clean humid airflow and condenses water vapor into liquid. As the machine collects water, the water "drops into a collection tank where it is ozonated to keep the water pure and fresh," according to the company's website. The machine further chills and filters the water before adding minerals to increase the pH level and improve the taste.
And then there's Drupps, a spinoff of humidity-control company Airwatergreen. It uses a completely different water-collecting technology that relies on a liquid desiccant to pull moisture from the air. The slurry is then heated and the water is boiled off, cooled and collected. While cost effective, there are some drawbacks. As with condenser-style water collection systems, Drupps' technology is energy intensive and thus less kind to the Earth.
Speaking of the environment, why go to the trouble of collecting water out of the air? Why not simply cause more rain to fall? It may sound far-fetched, but this is actually done — at times, with catastrophic consequences.