These are tiny little things, less than 4cm in diameter and floating on seawater. They rely on the sun shining on them to vaporize the water, and in fact the linked paper says that the convection cover is needed when outdoors in the wind.
So... it implies that you can't have anything blocking the sun from fully shining on it, because it already has enough problems gathering enough heat when the wind blows, right?
Where does this condenser go? Obviously, I don't know anything about engineering in this domain ;)
