Water From Air - Of Condensation And Salt
You've heard of the "Whisson Windmill", a label that Dr Max Whisson's water from air invention seems to be stuck with.
It extracts humidity directly from air. I've told you how this works in relieving some of the effects of global warming: water shortages and drought. It has attracted a lot of attention.
Now there are also other types of water from air machines. These are available right now. One works on a similar principle to Dr Whisson's which is to cool the air and capture condensed water vapour from it. A very elegant, and practical idea.
Of course energy sources are needed to run these machines and these four are being used.
- Wind energy, as used by the Whisson machine
- Electricity from the grid
- PV solar power
- Diesel generators
Bearing in mind the causes of global warming it makes a lot of sense to run these water from air machines on renewable power wherever possible. And free wind and solar energy is better than paying for diesel.
After all, you would not want to put more emissions in the air, that in turn contribute to global warming, that cause your drought and flood problems in the first place. Do you? And free wind and solar energy is better than paying for diesel.
OK, stay with me, let's start with the "condensation approach."
Water from condensed air – Air Water Pty Ltd' Air Water Machines
Similar to "Whisson's Windmill" the Air Water Pty Ltd's Air Water Machines also harvest water from air by using a condensation method. An example of the principle is the water you see on the ground under your car's air-conditioner, or the water in the bottom of your fridge: water from air!
These machines "pull air over a condenser, chill it and harvest the resulting water." Simple! Why did I not think of that!
This company's "Lifesaver" machine is the world’s first unique PV Solar Powered system that stands alone, in any place, 24/7, while producing huge amounts of water. The Lifesaver can provide water and power independence practically anywhere.
It produces 500 litres of water in 24 hours. It needs input power of 8.8KW and consumes 0.4kwH per litre of water produced.
See it in action here but make sure you enable your Firefox browser to play it, or use Internet Explorer.
It sells many different types of water from air harvesters,ranging from domestic use to that of a village!
The "Villager" produces 1000 litres per day (264 gallons) and the "Irrigator" an impressive 5000 litres (1321 gallons). At an estimated AUS 3c cents per litre this is still costly if using a diesel generator. But with wind or solar...
But this is still cheaper than the salt approach that I discuss below.
It seems water from air harvesting is destined to be part of your future and mine. Air Water says they foresee a future where these machines are as accepted as microwaves.
Water from air – the salt approach
In 2006 Aqua Sciences of Miami Beach, Florida, USA, sold several water making units to the Federal Emergency Management Agency (FEMA) who uses them for emergency water supply in the aftermath of natural disasters.
With extensive flooding, such as happened in New Orleans, water may be abundant, but is too polluted to drink. Water from air though is clean!
These portable units can make 1.200 gallons of drinking water per day at a cost of 20-40 cents per gallon. Cost varies with air humidity levels.
Clean water can be made right on the spot, where it is needed, rather than truck it in from great distances.
It can be packaged in strong bags, resembling those in boxed wine containers, for clean and safe distribution.
Water from air – how does the salt approach work?
The water from air machine works by forcing air through a liquid lithium chloride salt solution.
This is a hydroscopic compound. That means that it attracts water from its surrounding air.
Humidity is in the air both in arid and humid regions and this compound can harvest water in both. But the higher the air's humidity of course, the more can be squeezed out of it.
After absorbing water into this salt solution, it is extracted and filtered through table salt, which acts as a natural disinfectant.
Adding chlorine to water to achieve the same objective is possible but less preferred because of taste and things that can go wrong in the process.
As always, the less complex, the better the technology is.The final step is to filter this water through a carbon filter, which adds taste.
The company claims that this machine can still produce water in low humidity conditions. That's good news if you're in the outback somewhere and things are dry!These units normally run on grid electricity or diesel. But there are no reasons why they could not be run on renewable energy.
Water from air Disadvantages?
What about the salts used in this process? Does their harvest and manufacture produce greenhouse gas emissions? How are they disposed of?
These are as yet outstanding questions. You may know the answers. If you do, I'd be interested to hear from you.
Will a ready availability of almost magical water, anywhere, anytime, further erode our sense of connection with natural cycles? I argue for example that a sense of disconnection allows people to feel they can use and misuse the Earth's resources with impunity.
On the other hand this technology could ensure that at least some of the huge proportion of people presently without access to safe water sources will have it.
Of course greater numbers of healthy survivors then leads to thinking sustainably about population pressures on the Planet! But that's for another discussion.
|About 2.6 billion people – half the developing world – lack even a simple ‘improved’ latrine and 1.1 billion people has no access to any type of improved drinking source of water. As a direct consequence:|
- 1.6 million people die every year from diarrhoeal diseases (including cholera) attributable to lack of access to safe drinking water and basic sanitation and 90% of these are children under 5, mostly in developing countries;
- 160 million people are infected with schistosomiasis causing tens of thousands of deaths yearly; 500 million people are at risk of trachoma from which 146 million are threatened by blindness and 6 million are visually impaired;
- intestinal helminths (ascariasis, trichuriasis and hookworm infection) are plaguing the developing world due to inadequate drinking water, sanitation and hygiene with 133 million suffering from high intensity intestinal helminths infections; there are around 1.5 million cases of clinical hepatitis A every year.
These are World Health Organization figures.
Water quality at home too!
Water, water everywhere and not a drop to drink", is the famous sailor's lament. Maybe we are in that boat too. When you turn the tap, in many of our homes the water quality is such that you need to invest in filtering it.
Studies show the presence of over 2,100 toxins in US drinking water. Toxins found include chlorine, lead, chemicals from large farming run offs, and other pollution.
You cannot invest in a water-from-air unit (yet) but you can install your own home water filter systems
As always, human values underlie responsible use of technology, or otherwise.
You know what you can do about that. Talk to your lonely neighbour. Help someone! Volunteer in your local Environment Friends group. Get in touch with what dependence and fragility means, and to live well - within limits. You'll maker wiser life choices as a result.
It is therefore great to see that Air Water Pty Ltd contributes to the Natures Relief Fund, a charity to help those without good water.
Water shortages, global warming, renewable energy. Rightly, these topics are taking on major roles in your life... and that of your children. Subscribe to my RSS feed to keep in touch. See the orange 'RSS/XML' box in the margin, left and up.
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