This invention is about condensing water vapor from the air near the sea surface, directly onto cold freshwater, previously available in the system.

The freshwater is first cooled by one of two methods: (nothing inventive here yet)

1. Cold deep-sea water flowing through a coil or passing near heat ribs that pull the freshwater's heat into the deep sea cold water.

2. Spraying a mist of regular or even warm sea water and using the evaporation to cool the freshwater.

The damp water-vapor filled sea air is then sent through the cold freshwater to condense and add its vapor to the freshwater pool, as follows:

(a) The freshwater is pumped or sucked up and then sent to

(a1) drip down or

(a2) flow along open pathways or

(a3) to openly flow in downgoing verticle streams (like water from a home faucet) through the air, or

(a4) to be sprayed into the air creating a mist of cold droplets, or

(b) the damp air is pumped into the water creating bubbles emitting dry air and leaving the vapor condensed into the cold water. (watch Rohas' fascinating and unscientific videos boiling water with his Fresnel lens through a pipe going into a bottle of cold water)

The amount of condensed water received from the originally damp air, now added to the water in one of these five methods is compared with condensing water from damp air with:

(c1) the new materials for harvesting water in the desert, bio- mimicking beetles and desert plant surfaces, or just

(c2) cooled surfaces cooled by the same cold deep-sea water, or a combination of the two:

(c3) cooled surfaces made of the new materials.

and scientific conclusions are gathered.

I suspect that cold water droplets or several cold water streams will be cheaper and perhaps even more efficient than the new materials, and easier to construct. Thus using the cooling effects of deep-sea water, or water evaporated separately for cooling and using some pre-received freshwater to harvest freshwater from the sea.

If the sprayed mist or drops are found to work this may very well be close to the behavior of rain droplets in rain clouds.

I suspect that a counter-current system where the cooling and condensing are done in counter-current streams would be the best, in this case, sending the damp air through a very slight rise with cold freshwater dripping in all along from the top of the air pipe, from a small cold-freshwater pipe flowing downwards in the opposite direction via gravity.

The air continuously losing its vapor becomes lighter and tends to rise, but in any case, can be nudged in the right direction at the correct speed with a fan.
-- pashute, Mar 25 2018

Mist Rainmaker
[xaviergisz, Mar 25 2018]

random, halfbakery