Turning air into water? Gadget does just that

Tapping a hidden reservoir
Most environments around the world have plenty of water vapor that can be converted into liquid water. In fact, if you could wring out all the water in the air around the world and pour it into a lake, its volume would equal about 3,095 cubic miles, or more than that of Lake Superior, according to the U.S. Geological Survey.

Element Four estimates that its machine can convert between 10 percent and 40 percent of vapor into liquid water, depending on the relative humidity.

In 91 degree heat with 69 percent relative humidity, the machine tops out at a little less than 13 quarts per day. And because water vapor is continually replenished though the planet’s water cycle, removing it from the air could continue indefinitely without disrupting local ecosystems.

Ritchey said his company decided on the 13-quart capacity to maximize efficiency. Marketing data suggested that the typical family uses about half that amount of drinking water per day. But based on public perceptions that 6.5 quarts wouldn’t be enough, the company doubled the amount.

Other companies have begun producing upright units for indoor use or scaled-up outdoor units supported by fans and compressors that are capable of producing hundreds or even thousands of gallons of water per day. Miami Beach, Fla.-based Air Water Corporation, for example, can produce more than 1,000 gallons of water from a 3.5-ton mobile unit that resembles a small trailer.

Michael Zwebner, the company’s president and CEO, said 13 Air Water machines were deployed to Thailand and Sri Lanka after the 2004 tsunami. A camouflaged version is specifically aimed at the military, and units are already in use by the U.S. Marines, Indian Border Police and South African military, among other worldwide clients.

An even larger version in development can theoretically make as much as half a million liters of water a day (132,000 gallons). Later this month, the company expects to inaugurate an air-to-water facility that will give a remote Indian village its own water supply.

“The idea being that the 600 people in this village will not need to send their children many miles a day to collect water in buckets on their heads,” Zwebner said.

Likewise, Ritchey also had Third World applications in mind when he began tinkering with the WaterMill prototype in his basement nearly a decade ago.

With a model that runs on 110 volts AC and consumes about 300 watts of electricity, or the equivalent of 3,100-watt light bulbs, the company plans to branch out with a more portable unit that can operate on 12 volt DC power supplies. That modification would allow the unit to run on car batteries, photovoltaic panels, windmills or other sources of alternative energy.

More water, less energy
Greg Kail, spokesman for the American Water Works Association (AWWA), a nonprofit society focused on improving the quality and supply of drinking water, said he wasn’t familiar enough with the technology of atmospheric water generators to evaluate specific claims.

But he agreed that looming water shortages will require technological innovations, as well as more efficient devices in the home, better management at the utility level and smarter long-term planning.

Despite steady improvements in the technology that can provide fresh drinking water for about a penny per gallon in Air Water’s biggest units, according to Zwebner, that rate is still about 3.5 times more expensive than tap water production, based on the AWWA’s 2006 survey of 230 utilities throughout the U.S.

As for the WaterMill’s energy-efficient strategy, Ritchey said the unit can slow the airflow through the condenser if it needs to be cooled to a lower temperature to reach the dew point, meaning it would linger in a drier environment.

Even the WaterMill has its limits, though. Getting water when the relative humidity is less than 30 percent or 35 percent is “really pushing it,” he said.

Unlike most upright units that suck air from within a home or building, Ritchey said the WaterMill mounts on an exterior wall and uses outdoor air that is typically cleaner and more humid than indoor air.

Environmental Protection Agency-cited research suggests that the air within homes and offices can be far more polluted than outdoor air, with sources ranging from tobacco smoke and wet carpeting to cleaning products and pets.

Ritchey hopes his company’s commercial success will smooth the way for next year’s arrival of a humanitarian application called the WaterWall, essentially a stripped-down version of the WaterMill.

Within the “wall,” interconnected water condenser units can be individually engaged or disengaged as needed to overcome the problem of intermittent power in developing countries while providing a steady stream of water.

“We have a mandate as a company to do more than just make money,” he said. “We want to do some good in the world as well.”

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