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.
Field trial of the AKVOS water-from-air system in January 2018 on Sal Island, Cabo Verde. The water production module is on the left and the atmospheric water vapour absorption module is on the right. Water vapour in the air is aborbed by liquid glycerol flowing on the white fabric in the metal framework. The hydrated glycerol is transferred to the water production module. Solar heat is used to evaporate water out of the glycerol. The water vapour condenses into liquid water on the bottom inside surface of the module. Photo by Roland Wahlgren.
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.
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.