HOW PRACTICAL IS HARVESTING WATER FROM THE AIR?

Systems such as those built by companies like Tsunami Products are referred to as atmospheric water generators of the cooling condensation type. They work on much the same principle as a modern air conditioner, relying on a refrigeration circuit. The refrigeration circuit is used to create a cold surface upon which water from the air condenses and is collected. From there, the water is filtered and purified to remove any viruses, bacteria, or other contaminants that may have been captured from the air.


A Tsunami 500 unit pictured next to a human being for size.
It seems straightforward enough; the basic principle at play is quite simple. Collect water that condenses on a cool surface, filter it, and drink it! However, there's a reason that we don't typically look to the air itself as a source of water. That's because of the energy cost, which is, in a word, significant. Essentially, running such a machine is functionally equivalent to running a large air conditioner.

For example, the smallest unit offered by Tsunami Products is the Tsunami 500, which costs on the order of $30,000 and is reportedly capable of delivering up to 204 gallons (773 liters) of water per day. That's a lot of water, approximately enough to cover the daily needs of two Americans – 82 gallons of water each. To capture that water, the Tsunami 500 uses an astonishing 5.8-7.5 kilowatts, depending on ambient conditions of temperature and relative humidity. Multiply that out over 24 hours, and that water came at the cost of 139.2-180 kilowatt-hours. Looking at the best case, that's around 0.68 kilowatt-hours per gallon. In comparison, desalinating seawater, which is already considered energy-intensive, can be done for just 0.0113 kilowatt-hours per gallon.