Extracting water from the air is one method to generate freshwater, and, atmospheric water generators are one of the devices that have the capability to do this.
In this guide, we look at the potential pros and cons of atmospheric water generation, and also harvesting water from air in general.
Summary – Pros & Cons Of Atmospheric Water Generation (& Harvesting Water From Air)
Harvesting water from air (the atmosphere) includes all active and passive water-from-air harvesting methods.
For example, one passive method includes fog nets and fog fences.
Atmospheric water generators on the other hand are specific devices/units (run on a power supply) that actively extract water from humid ambient air.
There’s now several different brands that sell these types of devices, each with different features and capabilities.
Some of the potential benefits of atmospheric water generation and harvesting water from air might include diversification of a water supply and protection from future water risks, increased water independence, being able to generate water off grid and in remote or isolated areas, and having one more way to address water scarcity/stress related issues (and more sustainably manage and use water across society)
Some of the potential drawbacks of atmospheric water generation and harvesting water from air might include cost effectiveness, reliance on energy use to generate water (and also how dirty some of these energy sources can be), not being able to generate water at the largest scales/quantities, and needing specific conditions for some AWG devices to work most effectively.
Although there are some benefits in generating water from air, it doesn’t appear to be a ‘perfect’ or ‘magic bullet’ type of water supply option – at least not yet.
*Note
The type of water-from-air method used, the technology used, the individual brand and model, the conditions a unit is used in, available water supply alternatives, and other factors, are all variables in the overall pros and cons of AWG and harvesting water from air.
The pros and cons in this guide are generalized points only.
Potential Pros Of Atmospheric Water Generation (& Harvesting Water From Air)
Extracting Water From Air Is It’s Own Water Source
Devices/products that can extract water from the air are tapping into a water source that is separate to other water sources
Not only does this provide an addition water source, but it also means water-from-air units and devices aren’t directly withdrawing water from other sources like surface water, ground water and underground aquifers, or sea water)
Several Different AWG Technologies Exist
Such as air passing over a cool coil (causing water to condense), or, liquids and wet desiccants that pull water from the air.
Some technologies even use solid desiccants.
Overall, there’s different options and choices available for AWG technology.
Both Small, & Large AWGs Exist
Smaller domestic and household style units exist.
However, there are also large and more industrial sized units that exist too.
There’s obviously a difference in the scale of water generation of these different sized units.
… large wet desiccation units mounted on trailers, are said to produce up to 1,200 US gallons (4,500 l) of water per day, at a ratio of up to 5 gallons of water per gallon of fuel (wikipedia.org)
Rate Of Water Production Can Be Increased When Different Variables Change
There are different variables that can be changed in order to potentially increase the rate of water production/generation from an AWG unit.
[Rate of water production can depend] on variables such as the ambient air temperature, relative humidity, the volume of air passing over the coil, and the machine’s capacity to cool the coil or the size of the compressor (wikipedia.org)
Can Provide Drinking Water Straight From Some Devices
Some units are equipped with purification and filtration technology (and UV treatment), and other features, that may make it possible to provide drinking water straight from the unit.
Some AWGs also produce ice in addition to drinkable water.
Can Be Portable
Some smaller AWG units for example are mobile/portable, or easily transported from place to place.
No Installation Required For Some AWGs
Some companies ship their units out ready to connected to an energy source, and to start operating straight away.
AWGs Work Well In Some Conditions & Environments
I.e. conditions and environments that are better suited for water generation.
One example might be greenhouses where the air inside can be hotter and more humid than outside.
Climates and regions with moist air might be another example.
Might Be Used For Some Emergencies
Especially in situations where other water supply options other than bottled water aren’t available or suitable.
Examples may include natural disasters, or recovery efforts.
Might Be Used In Some Isolated Or Rural Locations
Especially in rural or non urban (remote) locations where there isn’t a lot of public water infrastructure set up.
Can Be More Economical To Provide Water Than Some Other Water Sources
For example, AWGs may be more economical in some instances than bottled water, home distilled water, and water tanks.
GENAQ provides a water supply price breakdown chart with some information on this
Some Methods Of Collecting Water From Air Are Passive & Don’t Need External Energy
Passive air to water harvesting methods rely on natural processes.
A fog fence or a fog net is an example of this, and air wells are another (passively collecting moisture from the air).
Energy To Water Ratio (Energy Efficiency) Of Some Active AWGs May Have Increased Over Time
This may help make AWGs more feasible from an energy usage perspective in some capacities going forward into the future.
May Have Some Other Sustainability Benefits, Or Show Some Other Sustainability Improvements
Apart from potentially becoming more energy efficient over time, or using cleaner energy sources over time, some other potential sustainability benefits or improvements might include:
– Some Large AWG Units Have Shown Development In Becoming More Environmentally Friendly
From wikipedia.org:
A variation of the large wet desiccation technology has been developed that is more environmentally friendly, primarily through the use of passive solar energy and gravity [and some other AWGs may use solar panels or solar hydro panels for solar power or solar heat to generate water]
– There’s Usually No Waste By-Product
Some AWG units have neither water waste, nor solid waste by products that are produced.
This is compared to desalination for example that does involve a waste by-product, such as brine.
Might Partially Help In Addressing Some Water Stress & Water Scarcity Issues
Being able to generate water from another source – the atmosphere – may help with augmenting a water supply in a geographic area.
This may partially help in addressing some water stress and water scarcity issues, as well as other water related issues being encountered by some cities and towns.
May Form Part Of A More Diversified Water Supply Strategy
A diverse water supply strategy may help protect cities and towns against future water security issues and water risks.
AWGs may be used alongside other water supply methods like rain water harvesting, desalination, water recycling, ground water and surface water withdrawal, and so on, as part of a diversified water strategy
May Contribute To Greater Levels Of Water Independence
The more control cities and towns, and even individuals (when considering reliance on private water sources where it’s legal vs public utilities), have over their water resources and supplies, the greater their level of water independence might be.
May Make Some Forms Of Off-Grid Living Better Or Easier In Some Instances
In instances where there’s electricity or fuel available, powered AWGs can be used.
In some instances where energy isn’t available, some passive air-to-water methods might be used.
The Utilisation Of Brackish Water With Some AWGs May Increase Potential For Drinking Water Generation
Potable water generation can be enhanced in low humidity conditions by using an evaporative cooler with a brackish water supply to increase the humidity (wikipedia.org)
New Developments & Technology May Lead To Improvements In The Future
Some of these development and technology may allow AWGs to function differently or function in an improved capacity in the future.
Potential Cons Of Atmospheric Water Generation (& Harvesting Water From Air)
Can Still Require A Significant Amount Of Energy To Operate
The condenser and fan systems in particular may take significant energy to operate.
Read some examples of the amount of electricity or fuel some units use to generate a certain amount of water in this guide.
May Have A High Carbon Footprint
This might especially be the case when coal is used as an energy source for electricity.
It can be one of the worst water sources environmentally when this is the case
Some estimates say it exceeds reverse osmosis seawater desalination by three times (wikipedia.org).
Some portable AWGs may also have the capability to run on a generator, and in this instance petroleum based fuels may also lead to a notable carbon footprint.
Water Input To Output Might Be Inefficient
This is the amount of water required to generate a certain amount of water as an output.
The more water input required, the less water efficient it is.
But, it depends on the type of water being used to – whether it’s a sustainable water source or not.
[An AWG] demands more than four times as much water up the supply chain than it delivers to the user (wikipedia.org)
May Not Be As Renewable Or Sustainable As Some Other Water Sources
This of course depends on the energy efficiency, total energy used, energy source used, and other sustainability and environmental impact factors specific to each individual unit.
It also depends on the water source it’s compared against.
Cost Effectiveness May Be An Issue In Some Instances
There’s the purchase cost, operation and maintenance costs, and end of life costs to consider.
Purchase and operation costs in particular may be significant.
The cost of alternative sources of water also have to be considered.
AWG technology can sometimes be more expensive than other water supply options such as home purified water, desalination water, surface water, and ground water – GENAQ provides a comparison chart of these costs.
Cost-effectiveness of an AWG depends on the capacity of the machine, local humidity and temperature conditions and the cost to power the unit [or, the cost of electricity/power in a city or town] (wikipedia.org).
Not All Individuals Or Countries Can Afford ‘Water From Air’ Technology & Systems
Both AWG units, and passive devices like fog nets cost money.
AWG units in particular can be more expensive/costly – particularly the operation of them.
Some cities and towns, especially lesser developed locales, can’t afford to purchase or operate them unless there is external funding.
The same applies for individuals – AWG technology is unaffordable for some.
Very Large Scale Water Generation Might Be An Issue In Some Aspects
AWG technology may not be suitable for some agricultural uses due to the sheer quantity of water required for tasks like irrigation and other agricultural tasks.
It might only produce enough water for smaller scale activities like drinking, cooking, cleaning, and general human use and consumption at home an in daily living.
Some Passive Air To Water Harvesting Methods May Need Specific Conditions To Be Effective
Fog nets and fog fences for example may need specific conditions in order to collect enough water
According to quantumrun.com, fog nets may need: ‘[… high humidity], high wind speeds and an adequate temperature change are required to harvest enough water from the atmosphere …’
Some Active AWGs Might Not Work As Effectively In Some Environments
AWG technology might work better when relative humidity and air temperature is higher.
[AWGs] might not work efficiently when the temperature is below 18.3°C (65°F) or the relative humidity drops below 30% (wikipedia.org).
EWG technology may also not be good in region and countries with very dry climates and dry air (as there is no moisture to extract in the air) – although some brands may say they make units for arid climates over 50ºC (122F) and relative humidity lower than 20% (although, this should be confirmed prior to purchase or use)
Each model of AWG by different brands might work ideally in different conditions – so you have to check the specifications and product details for optimal working temperature and relative humidity.
Cleanliness, Health & Safety Of Generated Water Needs To Be Checked & Confirmed
In the case of passive ‘water harvesting from air’ methods that don’t rely on patented technology and that don’t come with water purification and filtration devices, there may be water safety and health issues to consider
Also, in the case of AWG units, you have to consider factors such as purification of the air (which might be poor quality), and the final mineral content of the water, which can both impact water quality.
AWG units should meet legal requirements and regulations for water health and safety, with the ‘Safe Water’ Act in a given area being an example of a potential safeguard to follow for water users.
Distributing Water Might Sometimes Be An Issue
Sometimes, in order to distribute the water effectively to where it needs to go, the AWG needs to be set up in the right place.
If it’s not, there might be issues transporting it.
Noise Might Be An Issue During Operation Sometimes
Depending on the noise level of some units, this might be an issue for hearing long term, and, it may also be an issue when operating near individuals or groups of people in terms of noise pollution.
Some AWGs Can Be Heavy (In Terms Of Weight)
For example, a 1000 gallon a day unit can weigh 90,000lbs (total including PowerStation and panels) (solarcoldbox.com).
Although, some AWG manufactures make much lighter weight models for home use and casual or everyday use.
Heated Water Can Carry Additional Requirements & Costs
If there’s a requirement to heat the water from some devices or units, this may incur additional costs.
Although, some AWG manufacturers make hot and cold water dispenser models for home use that may address this in some capacity.
Peltier Semi Conducting Material Units May Have Their Own Pros & Cons To Consider
For examples, their solid state nature may make them suited to being portable units, but they may have low efficiency (of condensing water at commonly experienced humidity), and high power consumption
Sources
1. https://en.wikipedia.org/wiki/Atmospheric_water_generator
2. https://www.quantumrun.com/article/atmospheric-water-harvesting-our-one-environmental-chance-against-water-crisis
3. http://akvosphere.com/4-main-benefits-of-atmospheric-water-generators/
4. http://akvosphere.com/akvo-atmospheric-water-generators/
5. https://tuafi.com/why-tuafi/
6. https://www.csiro.au/en/Do-business/Commercialisation/Marketplace/Atmospheric-water-generation-prototype
7. https://www.epa.gov/water-research/atmospheric-water-generation-research
8. https://www.watergen.com/
9. http://www.genaq.com/water/
10. https://www.skywater.com/
11. https://home.howstuffworks.com/atmospheric-water-generators.htm
12. https://solarcoldbox.com/solarwatermaker
13. https://www.watergen.com/product/gen-l/
14. https://www.watergen.com/product/genny/
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