Source: Nature Communications article

Background: Add review articles

The Basic Idea: Make a gel/foam with enormous surface area. Include a deliquescent salt like LiCl to pull water out of the air. Get extra clever by adding methyl propyl cellulose which has a very interesting property. It has two solid states. In the lower temperature state the polar groups are on the surface. Above 50C it changes to a different solid state with non-polar groups on the surface. If dissolved in water it will come out of solution above 50C. In this case it expels the water that isa adsorbed to the LiCl.

By cycling the temperature above and below the phase change 14 times in 24 hours they were able to collect 4 times the weight of the foam in arid desert conditions.

The New Idea: Use something like the design above to move from the laboratory to the field. This design uses only passive solar radiation.

Outstanding Questions:

• What are the thermodynamics? Is the heat of vaporization any different than the heat of desorption? How much air has to be moved? Does the air have to be heated and cooled? (Note: In condensation systems that drop the temperature below the dew point most of the energy removed is needed to cool the air. This is even more than the amount removed to condense the water.)

• Will the materials last outside in the elements?

• Will bugs eat the foam?

• Will mold grow on the foam?

• What will the built cost be?

• How long will an installation last?