Around the world, water shortage is increasing in severity. Many large population areas are located close to seas and oceans. This invention utilizes solar energy to distill water from sea water or even brackish and dirty water sources, such as polluted rivers and lakes. The main components are (1) a large metal umbrella shaped shroud floating in the air 5 to 10 feet above the surface of the water, (2) solar heat exchanger aluminum tubes with heat collecting plates, and flotation tanks to hold them up at the surface of the water, (3) a submerged water vapor condensor tank, (4) a flexible and elongating hose/duct to transfer water vapor into the tank (the vapor may also condense along the hose) (5) water pump activated by a liquid level switch to pump water to land based water tanks.
There may be a number of heat exchangers depending on the size of the unit. This design can be scaled up or down as required. The bottom of the heat exchangers sit just below the water, about 10" to 1ft, held in place by the air-tanks. The shroud is held aloft by the heat exchangers. The net underneath the shroud prevents water splashing into the vapor intake and keeps insects out.
I chose aluminum because it is much cheaper than copper but has very good heat conduction coefficient, compared to steel, while it is resistant to corrosion. The condensor collector tanks may be made of silicon coated steel sheets to lower costs.
The shroud and the heat exchangers collect solar heat and are at high temperatures during the day. The condensor tank is submerged whereby it is held at a lower temperature enabling condensation of vapor. The pressure inside the tank is held slightly below ambient as the water is pumped away. This enhances the inward flow of vapor.
Evaporation of water also occurs during the night and the shroud is able to collect and transfer the vapor to the condensor tank. Several of these units can be placed in shallow seas, near towns, the numbers depending on water demand. The shroud that is the main visible part of the unit can be modified for aesthetics and blending in with environment.
If the pump is powered by photovoltaic cells, the unit can be placed anywhere without cables. The condensor tank may be coated with material to promote coral production.
The form and shapes can be altered to allow a specially tailored application in any location where water collects, e.g., the condensor tank may be modified in shape and even merged with the shroud to form one unit. Also, if the water level is low, the condensor tank can be placed about 10 feet under the ground where temperatures are low, while the shroud and heatexchangers are placed over the water surface. In case of soluble gas borne impurities, such as sulphurous compounds, further filtration may be required before consumption. More details are available and more enhancements are possible.