Given the continued shortage of fresh water in many parts of the world, especially in the Middle East, my thoughts again turn towards making use of the run-off water created by air conditioners during the hot, sticky summer months. This idea has also been suggested as a solution for the fresh water shortage in UAE countries like Dubai and Abu Dhabi, where it may be possible to condense the heavy humid air, with humidity levels often as high as 85%, into potable water supplies that can be used for both human consumption and agriculture.
How much AC water can this building produce?
The argument of using “AC water” for agriculture and other uses, including human consumption, has up to now been discouraged due to fears of too much bacteria and other “creepy crawlies” being present in it.
There is also the concern about the presence of harmful chemicals created by the cooling coils of an air conditioning system.
This may also be true; but when you think about it, water supplies that come from water storage reservoirs (like Lake Kinneret in Israel or Lake Aswan in Egypt for example) are similarly full of “creepy crawlies” including all kinds of swimming protozoa and water borne parasites that can find their way into our bodies and cause a number of medical problems.
All water supplies, including that derived from AC units, can be purified for drinking by water treatment plants. For those living in areas where municipal water treatment facilities are not available, a simple and very inexpensive way of killing bacteria in well or even AC water can be made by filling plastic bottles with water and allowing the filled bottles to lay in the sun for several hours. This method, mainly for use in developing countries, is now being done by a company named Sodus which involves placing a number of filled bottles in special racks on the roofs of houses.
The SODUS water purification process utilizes the sun’s ultraviolet rays to purify the water, killing harmful bacterial growth and other disease causing organisms. To enable the water to heat faster, it is recommended to paint one side of the bottle black and then place the bottle on a roof or other surface with the black side down. This acts like a miniature sun boiler, and works on a similar principle as solar water heater collecting plates. All that is left to do is some basic filtering though activated charcoal to remove any discoloring caused by soil and other particles present in the water.
(That said, we do have to wonder about the potential carcinogenic effects of leaving plastic in the sun?)
My previous article on this topic noted that a 1 hp air conditioner left running for 6-8 hours during the night will produce as much as ten liters of water, depending on how much humidity is present in the air. If this much water can be produced daily from such a unit, think of how much water can be produced from a large commercial AC system in an office building like Dubai’s Burj Khalifa Tower (pictured above) or a large shopping mall.
At present, most of this water is being literally allowed to go down the drain. But if “harvested” and purified properly, it’s possible that in the summer months, this idea could produce as much as 15% of more of our fresh water needs.
Water from air? Of course, and the time to use this hidden resource is now!
Read more on AC and “water from air” possibilities: