This article is a nice up-to-date review about water-from-air technologies. Tim Smedley, the writer, interviewed me about some of the information that appears in the article. You can find the online article by clicking on the image above.
For blog readers who may relish a scientific conference about water—The Welch Foundation Conference on Chemical Research "Water: Science and Technology" will take place in Houston, TX October 22-23, 2018. I am going! You can learn more about the conference at http://www.welch1.org/conference/conference-program —be warned— the experience will likely be similar to attending university lectures in chemistry and physics!
In response to a reader's comments, the July 2018 reprinted second edition incorporates enhanced temperature versus relative humidity psychrometric tables in Chapter 4 with wider temperature ranges (0–55 °C; 32–132 °F) for finding water vapour density, humidity ratio, and dew-point. This makes the tables more useful for cities like Abu Dhabi, Doha, and Dubai.
This reprint also has a revised Appendix 6: Economics of Off-grid Solar PV for WFA. There are two detailed examples in the Appendix. The first example is for a 1.05 kW input power atmospheric water generator using 1-phase electric power. The second example is for a 2.1 kW input power atmospheric water generator using 3-phase electric power.The Appendix presents clear diagrams showing the main components of single-phase and three-phase off-grid solar PV systems. The Appendix concludes by revealing, for each example, the ratio comparing the price of an off-grid solar PV system to the price of the atmospheric water generator.
The Water-from-Air Quick Guide may be purchased from Amazon.
Did you know LinkedIn has a group devoted to the topic of Atmospheric Water Generators? It has 50 members at this time. The Group Owner is Stuart Shapiro, EVP at Infinite Water, Inc.
I encourage anyone interested in the water-from-air field to join the group and contribute to discussions relevant to AWG technologies.
Five new products, of interest to professionals involved with pyschrometrics, meteorology, HVAC, dehumidification, and water-from-air systems (atmospheric water generators) have been added to the category, "Tables" in the Atmoswater Research online store:
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.
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".
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.
I discovered several interesting bits of knowledge about dew and dew condensers in this article by a team of dew researchers:
Beysens, D., Milimouk, I., Nikolayev, V. S., Berkowicz, S., Muselli, M., Heusinkveld, B. & Jacobs, A. F. G. 2006. Comment on "The moisture from the air as water resource in arid region: Hopes, doubt and facts" by Kogan and Trahtman. Journal of Arid Environments 67(2), 343–352.
Here are the bits I chose to highlight:
Cite as: Wahlgren, R. V. (2014, October) Another Water Resource for Caribbean Countries: Water-from-Air. Paper presented at the Caribbean Water & Wastewater Association, Twenty-Third Annual Water & Wastewater Conference and Exhibition, October 6–11, 2014, Atlantis, Paradise Island, Bahamas. Retrieved from https://s3.amazonaws.com/eventmobi-assets/eventsbyids/6712/documents/seminar/424180/Wahlgren,_R_11_Paper-WaterFromAir.pdf
The paper I presented at the Caribbean Water & Wastewater Association Conference 2014 is now available at https://s3.amazonaws.com/eventmobi-assets/eventsbyids/6712/documents/seminar/424180/Wahlgren,_R_11_Paper-WaterFromAir.pdf
This is Figure 3 from the paper showing the Caribbean water-from-air resource during June. The resource is represented by the composite mean specific humidity for the ten months during 2004 to 2013. Image provided by the NOAA/ESRL Physical Sciences Division, Boulder, Colorado from their web site at http://www.esrl.noaa.gov/psd/; NCEP Reanalysis dataset (Kalnay, E. and Coauthors, 1996).
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.
A Water-from-Air System Hourly Analysis Model for San Francisco, California is available as a free download on the Atmoswater Research website. During the prevailing California Drought, seventeen rural communities were identified by the California Department of Public Health as having "drinking water systems at greatest risk". Two of the affected counties, Sonoma and Santa Cruz are adjacent north and south respectively to San Francisco. Therefore, it is interesting to take a tour through the San Francisco hourly analysis model to see what it can tell us about the feasibility of using water-from-air machines (atmospheric water generators) as alternative or additional water resources in drought affected communities in Sonoma and Santa Cruz.
Tour Stop 1
Tour Stop 2
Tour Stop 3
Tour Stop 3: Daily Average Water Production by Month with an interpretation of the modeled result. In a water crisis situation, each person needs 5 L/day of drinking water. Total daily water demand per person to take care of their drinking, cooking, sanitation, and bathing needs is typically 50 L/day. (Click to enlarge)
Tour Stop 4
Tour Stop 5
Tour Stop 5: With an average daily water production of 703 L/d, one machine could serve 14 people at the 50 L/d level or 140 people at the minimal 5 L/d level of drinking water consumption. Water storage is needed to distribute the annual water production evenly over the year. Several machines can be distributed throughout a region to serve larger populations. Water-from-air is a unique decentralized way of obtaining water. It is not absolutely necessary to think of a central water production hub. The machines can be placed where they are needed.
Tour Stop 6
Tour Stop 7
Tour Stop 8
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)
I hope you found this tour interesting! The entire model output consists of 120 pages. Becoming familiar with how a water-from-air machine responds with its freshwater production to the hourly weather at a site is a unique experience that really helps make sound decisions about whether or not to use these machines in various drought situations.
The San Francisco model shown here used weather data from 1993 because that was available as a free sample from a weather data vendor. Given the realities of climate change it would be interesting to run the model with 2013 data.
I can run models for key drought locations in California. The price per model run report is [ask for quote] (USD). Please allow up to five business days for delivery as a PDF download.
Why use a Water-from-Air Resource Chart? Well, this colourful output from a computer model is a marvelous tool for understanding how well water-from-air machines (atmospheric water generators; AWGs) would perform at your location. "Knowledge is power"--there is value to being well-prepared before talking to equipment suppliers, consultants, or project colleagues.
Let me guide you through this information-packed chart.
Charts for many different locations are available from Atmoswater Research. You are welcome to ask me to produce charts for places of interest that are not listed yet.
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.
"España sufre sequías cada vez más intensas y prolongadas" _["Spain suffers droughts that are increasingly long and prolonged"; Interempresas.net]
Water-from-air Resource (WFAR) Resource Charts are available for five sites in Spain. These sites represent five climate zones. Operating conditions by month for atmospheric water generators range from unreliable to excellent depending on site latitude, elevation, distance inland, and season. Please see the charts for details.
The table below ranks the sites from highest to lowest WFAR Annual Index. Water production is poor or unreliable during the winter months. Hourly water production analyses would be useful for better understanding the feasibility of water-from-air system operation at these sites.
Jamaica has a history of droughts. The most recent was in 2013.
A Water-from-air Resource (WFAR) Resource Chart is available for Kingston, Jamaica. This site (9 m elevation) is in the equatorial | winter dry climate zone which encompasses the entire island country. Operating conditions by month for atmospheric water generators are consistently excellent.
Please see the chart for details. The Water-from-Air Resource Annual Index = 1.22.
Important environmental issues in Egypt are water scarcity, pollution of the Nile River, solid waste, and loss of biodiversity (UNEP, 2013, Arab Region Atlas of Our Changing Environment, page xiv). Can water-from-air technology address the water scarcity issue?
Water-from-air Resource (WFAR) Resource Charts are available for three sites in Egypt. These sites represent one climate zone. Operating conditions by month for atmospheric water generators range from unreliable to excellent depending on site latitude, elevation, distance inland from the Mediterranean Sea, and season. Please see the charts for details.
The table below ranks the sites from highest to lowest WFAR Annual Index. The coastal site of Alexandria is suitable for year-round effective operation of water-from-air systems even though the water-from-air resource grade ranges from poor to excellent. In contrast, Cairo and Aswan will have periods of unreliable operation during the low sun season. Hourly water production analyses would be useful for better understanding the feasibility of water-from-air system operation at these sites.
Important environmental issues in Kuwait are water scarcity, groundwater salinity, land degradation, desertification, pollution, and impacts of the Gulf War (UNEP, 2013, Arab Region Atlas of Our Changing Environment). Can water-from-air technology address the water scarcity issue?
A Water-from-air Resource (WFAR) Resource Chart is available for Kuwait City. This site (54 m elevation) is in the arid | desert | hot arid climate zone. Operating conditions by month for atmospheric water generators range from unreliable to fair.
Please see the chart for details. An hourly water production analysis would be useful for better understanding the feasibility of water-from-air system operation in Kuwait City (Water-from-Air Resource Annual Index = 0.45).
Important environmental issues in Algeria are desertification, water scarcity, and pollution (UNEP, 2013, Arab Region Atlas of Our Changing Environment, page xiv). Can water-from-air technology address the water scarcity issue?
Water-from-air Resource (WFAR) Resource Charts are available for four sites in Algeria. These sites represent three climate zones. Operating conditions by month for atmospheric water generators range from unreliable to good depending on site latitude, elevation, distance inland from the Mediterranean Sea, and season. Please see the charts for details.
The table below ranks the sites from highest to lowest WFAR Annual Index. The coastal site of Algiers is suitable for year-round effective operation of water-from-air systems even though the water-from-air resource grade ranges from poor to good. In contrast, Batna, Biskra, and I-n-Salah will have periods of unreliable operation during the low sun season. Hourly water production analyses would be useful for better understanding the feasibility of water-from-air system operation at these sites.
I have been researching and developing drinking-water-from-air technologies since 1984. As a physical geographer, I strive to contribute an accurate, scientific point-of-view to the field.