I've just calculated that polished copper can condense water vapor at a rate 17X that of water itself.

So, if a cool, dry, polished copper surface was exposed to air with adequate humidity, it would begin condensing water.

If it was then wiped away and collected, it would continue attracting water at 17X the rate of the wet copper.

If true, that system could be a highly efficient source of water.

Today's condenser systems have the water dripping off, keeping the condenser always wet.