very nice direct approach, do have questions about the diameter of the holes they choose (1/8-inch) versus the thickness of the barrier layer.

also the reservoir below will have to be significant enough that increasing the salinity below does not adversely change the buoyancy of the floating insulation with the convection holes enough to make the evaporation layer above too thin.

that is; in the closed system shown the insulation will float higher as the water is evaporated eventually self limiting