Ancient Israelites collected morning dew from stones. There are prayers for dew in the Bible, and the recipe for the traditional Jewish bread —— challah —— includes how much dew to use in the batzhek (the dough). So it's not a far-fetched idea that clean technology developers in Israel look to this ancient method of water extraction to solve water scarcity problems around the globe.
An Israeli company EWA believes they have found a way to get around the enormous amount of energy needed to be input in order to collect water from air —— even in desert regions. Putting aside their solar powered air conditioning invention to take care of a more pressing concern for water, EWA, has created a new humidity collection device expected to see $5 million in sales by the end of this year, and $100 million by the end of 2009. Who's buying?
EWA (which stands for Extraction of Water from Air), has developed a clean technology that extracts water from the air, while using little energy in the process. The key they say is in its unique water adsorption technology - which employs a solid desiccant to trap the water - and a special energy saving condenser that reuses more than 85 percent of the energy input to the system.
Renewable energy sources, such as solar power, biofuel, waste heat or even the heat from organic matter are compatible with the system.
The company, which was founded in 2006, is based on nine years of research by Etan Bar, a former researcher at Ben Gurion University. The company now has representatives in the US, India, Jordan, Cyprus, Australia and West Africa where EWA is helping farmers generate carbon credits, on top of providing them with clean water for drinking and irrigating their crops.
The technology, Bar tells me when writing a story about them for ISRAEL21c, works in three steps:
1. First is the absorption of air's humidity.
2. Then the removal of water from a solid desiccant (silica based gel granules) which holds the water.
3. And third, condensation.
The absorption of the humidity is an exothermic process (involving heat release), humidity absorption occurs spontaneously, and only minimal energy is used as the air is pumped through the unit. Heat recovery techniques are integrated as part of the condenser, reducing the cost for producing water to a reasonable price, similar to other processes, such as desalination.
Water is not created equal
Making use of renewable energy sources enables EWA to supply water at cheaper cost because the need for long distance piping and infrastructure (the water consumer is the water producer) is erased from the equation.
In countries like America and Canada where freshwater is abundant, people take long showers for granted. Today in less fortunate developing and even developed nations - such as Cyprus — the cost of water is so high that even in 4-star hotels water to the shower taps is being turned off, Bar tells ISRAEL21c, after a recent experience on the Cypriot island. There a cubic meter of water costs 6 Euros, because it is transported all the way from Greece.
To compare - according to the US-based Global Policy Forum, the average American household consumes about 480 cubic meters (127 thousand gallons) of water during a year. While homeowners in Washington D.C. pay about $350 a year (72 cents per cubic meter), buying the same amount of water in the slums of Guatemala City would cost about $2,000.
More than a drop in the bucket
Even though clean water for drinking and bathing seems like a basic human right, for most of the worlds' poor it is a luxury. EWA hopes to change that: "One cubic kilometer of air contains 10 to 40 thousand tons of water — enough to supply at least 100 thousand people with all their water needs, or enough 'safe' drinking water for two million," Bar explains. EWA's device, can be scaled up or down, and will produce anywhere from a few hundred liters of water per day to 1,000 cubic meters of water in a single plant.
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