Water-from-air systems often use ultraviolet light means to sanitize the incoming air, the stored water, and the water as it is being dispensed. This 4-page fact sheet, by the nonprofit IUVA, is useful knowledge for the water-from-air industry community as it copes with the COVID-19 pandemic.

Recently, I was invited to discuss some aspects of water-from-air technologies as posts (each about a one minute read) in the GWW Connect Network. I posted the seventh and final article today. Here are links to the posts.

1. Significant Milestones
2. Crucial success factors for companies to remain viable in the water-from-air market
3. Where do I see the most impact from water-from-air technology solutions?
4. What should investors know before investing in the water-from-air industry?
5. What should users of water-from-air systems know about implementation and maintenance?
6. What type of training do I recommend for someone interested in entering this field?
7. What are my favourite breakthroughs in the water-from-air field?

This newly published article, by water industry experts Mary Conley Eggert and Graham Symmonds, is worthwhile reading for current perspectives about the role of water-from-air technologies in drinking water supply infrastructures.

This YouTube video by the Dutch foundation, Happy With Water Foundation, reviews several atmospheric water vapour processing methods and then states that an absorption cooling method using solar energy and vacuum tubes with heat pipes reduces the energy cost of water making it relatively more affordable and practical compared to most other options.

For some time I have wanted to highlight this interesting water-from-air system. The photo shows a prototype system using glycerol as the liquid desiccant to absorb water vapour from the air on Sal Island in the eastern tropical Atlantic Ocean (17°N, 23°W). The prototype was designed and built by Dr. Pavel Lehky who holds United States Patent 9,200,434 B2 for the system. The field trials were done during Team AKVOS's participation in the Water Abundance XPRIZE competition. I was a member of the team. During a typical night at the site, the absorption module with its 9 square metres of surface area absorbed over 4 L of water. The 0.25 sq. m. production module was able to recover about 0.3 L of this during a typical day. So, one of the lessons from the trial was the water production module area has to be better matched to the capacity of the absorption module. Improving the efficiency of the water production module is also of benefit—this is a focus of ongoing design improvements. Find out more about Stiftung Sanakvo (Team AKVOS) at their website. Sanakvo also has a video on YouTube with an explanation of the system and showing the prototype operating during the field trial.

The University of California, Berkley research group led by Omar M. Yaghi published recently an article in ACS Central Science describing how they built and tested a metal-organic framework water harvester prototype. The system produced fresh water at the rate of 0.7 L/day in the Mojave Desert during a 3-day trial (October 17–20, 2018). During this period the ambient air dew-point was less than 5 °C for 85% of the time. 

You can read the update by Jeff Szur at this link: ​https://mailchi.mp/5b1d9c7272fb/my-new-venture?fbclid=IwAR3ZLsQGIUKDRT3lPfATLn4ATO2Shjfjs1QKXEus_9L5rZRl2N1cUL0FBt0

Today, I learned about Aalto University's Water Scarcity Atlas from The Water Network. The atlas is a useful and credible resource for learning about various aspects of the water supply challenges facing humanity. For those of us in the water-from-air community it is definitely worth visiting and bookmarking. The atlas is a useful guide to the regions on which to focus water-from-air research and development efforts.The data & code section of the atlas website had a link to the City Water Map Initiative whose data source was

McDonald and others (2014). Water on an urban planet: Urbanization and the reach of urban water infrastructure. Global Environmental Change 27, 96–105.

This paper gives the results of the first global survey of the water sources for the world's largest cities. Table 2 in the paper lists the largest cities enduring water stress. The cities (in order of population) are Tokyo, Delhi, Mexico City, Shanghai, Beijing, Kolkata, Karachi, Los Angeles, Rio de Janeiro, Moscow, Istanbul, Shenzhen, Chongqing, Lima, London (UK), Wuhan, Tianjin, Chennai, Bengaluru, and Hyderabad.

Enjoy watching our 4 minute 40 second video presentation about using mechanical dehumidification technology for obtaining drinking water from the water vapour in the air. To access the video, just click on the image above.

Chemical & Engineering News published an interesting article about drinking-water-from-air technologies which may be accessed at ​by clicking on the page excerpt image above.

The September 28, 2018 earthquake and tsunami disaster in Palu has caused shortages of clean water (see for example, "Palu earthquake, tsunami victims get clean water support", The Jakarta Post). The Water-from-Air Resource Chart for Palu is a free download.  

Moscow and London among the cities that could run out of drinking water? Yes, according to a BBC report in February 2018.

Moscow's drinking water comes mostly from surface water. Industrial pollution affects surface water in Russia.

London has relatively low average annual rainfall feeding the Thames and Lea rivers which supply much of London's drinking water. Capacity limits are being approached and are likely to be exceeded in the next couple of decades.

Although Moscow and London are not ideal sites for a year-round water-from-air resource, there is enough moisture in the air during the summer months to allow machines to operate.

The new Water-from-Air Resource charts for Moscow and London, now available for purchase and download at the Atmoswater Shop, will be of interest to city planners and others concerned about ensuring water security for the people living in these two cities.
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• Nature Conservancy reference 

​Thermoelectric cooling technology has had wide appeal as an alternative to mechanical refrigeration cooling technology for at least twenty years. Thermoelectric systems avoid the use of hazardous, harmful refrigerants and noisy compressors​. Low coefficient of performance (COP, in the range of 0.9–1.2) is the main problem preventing widespread use of thermoelectric cooling especially for systems requiring large cooling capacities (Riffat & Ma, 2004). A COP of 1.2151, achieved using a multistage thermoelectric module, was considered "remarkable" by Patel and others (2016)  Only smaller capacity niche applications have been commercialized.

There have been several peer-reviewed papers published and patents issued for atmospheric water generators or dehumidifiers using thermoelectric cooling devices which use the Peltier effect. Some information and products have been featured on websites. Each reference below represents a clickable link to more information.

Examples of papers

Atta, R. M. (2011). Solar Water Condensation Using Thermoelectric Coolers. International Journal of Water Resources and Arid Environments, 1(2), 142–145.

Milani, D., Abbas, A., Vassallo, A., Chiesa, M., & Bakri, D. A. (2011). Evaluation of using thermoelectric coolers in a dehumidification system to generate freshwater from ambient air. Chemical Engineering Science 66(12), 2491-2501.

Muñoz-Garcia, M. A., Moreda, G. P., Raga-Arroyo, M. P., and Marin-González, O. (2013). Water harvesting for young trees using Peltier modules powered by photovoltaic solar energy. Computers and Electronics in Agriculture 93, 60–67.

Nandy, A., Saha, S., Ganguly, S. & Chattopadhyay, S. (2014). A Project on Atmospheric Water Generator with the Concept of Peltier Effect. International Journal of Advanced Computer Research, 4, 481–486.

Suryaningsih, S. & Nurhilal, O. (2016). Optimal design of an atmospheric water generator (AWG) based on thermo-electric cooler (TEC) for drought in rural area. AIP Conference Proceedings 1712, 030009 (2016); doi: 10.1063/1.4941874

Davidson, K. B., Asiabanpour, B., & Almusaied, Z. (2017). Applying Biomimetic Principles to Thermoelectric Cooling Devices for Water Collection. Environment and Natural Resources Research 7(3), 27–35.

Examples of Patents

Peeters, J. P. and Berkbigler, L. W. 1997. Electronic household plant watering device. United States Patent 5,634,342. [expired, now in public domain]

Wold, K. F. 1997. Plant watering device and method for promoting plant growth. United States Patent 5,601,236. [expired, now in public domain]

Reidy, J. J. 2008. Thermoelectric, High Efficiency, Water Generating Device. United States Patent 7,337,615.

​Waite, R. K. & Neumann, A. (2017). Water production, filtration, and dispensing system. United States Patent 9,731,218 B2.

​
Examples of Websites

The "instructables" website published the article "How to Make a Dehumidifier (Thermoelectric Cooling) in 2016.

Amazon.com sells several models of "thermoelectric portable compact dehumidifiers".
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​References

Patel, J., Patel, M., Patel, J., & Modi, H. (2016) Improvement in the COP of Thermoelectric Cooler. International Journal of Scientific & Technology Research 5(5), 73–76.
​
Riffat, S. B. & Ma, X. (2004) Improving the coefficient of performance of thermoelectric cooling systems: a review. Int. J. Energy Res. 28: 753-768 (DOI:10.1002/er.991)

The target market for atmospheric water generators, in the broadest sense, are people in locations with perennial water shortages due to population growth, climate change, and lack of enough sustainable surface or groundwater within a radius of 100 km. The reference for these defining conditions is: Lalasz, R. (2011). New Study: Billions of City Dwellers in Water Shortage by 2050; retrieved from https://blog.nature.org/conservancy/2011/03/28/pnas-billions-city-urban-water-shortage-2050-nature-conservancy/. A study led by the Nature Conservancy defined these conditions. At least 23 cities fit these conditions. From north to south they are: Shenyang, Beijing, Tehran, Haifa, Tel Aviv, Jerusalem, Lahore, Delhi, Dubai, Riyadh, Abu Dhabi, Kolkata, Mexico City, Mumbai, Hyderabad, Manila, Chennai, Bengaluru, Caracas, Lagos, Cotonou, Abidjan, and Johannesburg. Some small tropical islands such as Grand Turk, Turks and Caicos Islands and Sal Island, Cabo Verde also fit these defining conditions. Recent reports such as “The 11 cities most likely to run out of drinking water - like Cape Town” by the BBC (http://www.bbc.com/news/world-42982959; 11 February 2018) suggest that we could add other cities to the Nature Conservancy’s list. From the BBC report here are nine more cities to add to the list of those likely to run out of sustainable natural water supplies: Cape Town, São Paulo, Cairo, Jakarta, Moscow, Istanbul, London, Tokyo, and Miami.Water-from-Air Resource Charts are available for all the highlighted locations mentioned in this post—just click on the location name to go to the relevant page in the Atmoswater Shop. By the way, if you like bargains, the charts for the 23 water-scarce cities listed by the Nature Conservancy are all included in the book, Water-from-Air Quick Guide.

Several new water-from-air resource charts for cities in India are now available for purchase and download at ​https://www.atmoswater.com/store/c130/India.html. The cities include Bikaner, Dhubri, Dibrugarh, Kota, Srinagar, and Trivandrum. 

I have the privilege of being accepted as one of the presenters during the Technical Sessions at the 23rd Annual Caribbean Water and Wastewater Association (CWWA) Conference and Exhibition scheduled for October 6-10, 2014 at Atlantis Resorts on Paradise Island, Bahamas. Here is the Abstract of my paper:

Regional droughts in the Caribbean are common. Water managers seeking solutions to water scarcity are often unfamiliar with the option of using water-from-air technology. Maps of the specific humidity composite mean for Junes and Decembers during the ten-year period 2004–2013 quantify the water-from-air resource demonstrating it is suitable for operation of water-from-air systems in Caribbean countries. Quantitative investigations by the author found droughts and long-term climate change do not appear to affect the magnitude of the Caribbean region’s water-from-air resource. Case studies include one for a proposed water-from-air commercial greenhouse on Grand Turk. Another case is about the experience of commissioning a 2500 L/d water-from-air machine in Belize City. Lessons learned from the case studies are outlined.

Air masses with relatively high water vapor densities (exceeding 12 grams of moisture per cubic meter of moist air) surround San Francisco / San Jose and Los Angeles / San Diego. 'Good' performance is expected from water-from-air systems (atmospheric water generators) operated in these regions. Over the balance of the state, the water-from-air resource is graded as 'fair'.

This map is from the new Atmoswater Research 45-page publication, Atlas of the Water-from-Air Resource for California.

Tour Stop 8: In San Francisco, the diurnal regime of the water-from-air resource is somewhat variable with the seasons. (Click on images to enlarge them)

Abstract from my article published February 11, 2014 on Water Online:

Quantifying the water-from-air resource enables targeting selected cities where installing strategically located stand-alone processors of atmospheric water vapor will have the quickest, most beneficial impact for people facing water scarcities.