SOLAR-POWERED DESALINATION SYSTEM

Abstract

This invention has a series of multiple parallel plates that form desalination chambers between them that have seawater or other saline water flowing down the inside of one plate of each chamber. Steam which is generated by solar heat or other heat source condenses on the outside of first chamber of the series on the plate, which has seawater running down it. This releases heat that evaporates the seawater. The vapor flows to the other wall (plate) of the desalination chamber and condenses, and this releases heat that flows through the plate to the next stage of parallel plates and evaporates seawater flowing down the other side of the plate. Each succeeding stage operates at a lower temperature than the previous stage. The final stage is cooled by the evaporation of seawater into the air. One embodiment of the invention has the parallel plates sloped at an angle to the horizontal so that the seawater flows down on the lower plate and evaporates with heat supplied from below. The vapor condenses on the ceiling of the chamber. Since each succeeding stage upward is at a lower temperature, the vapor pressure will be lower in succeeding stages. This pressure differential can be used to pump the seawater from one stage to the next higher stage.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The accompanying drawings, which are incorporated into and form a part of the specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the invention. The drawings are only for the purpose of illustrating preferred embodiments of the invention and are not to be construed as limiting the invention. In the drawings:

FIG. 1 is a cross-sectional side-view schematic of one embodiment of the present invention in which the parallel plates and desalination chambers are slanted with respect to the horizontal.

FIG. 2 is a bottom view schematic of one of the plates that separate the desalination chambers showing cords that use capillary action to collect condensed water and carry it to side troughs.

FIG. 3 is a side-view schematic drawing of a u-shaped pipe that prevents vapor from flowing from one stage to the next.

FIG. 4 is a cross-sectional side-view schematic of another embodiment of the present invention in which baffle plates are inserted within each desalination chamber to guide the vapor flow so that all entrapped air will be delivered to the vent pipes.

FIG. 5 is a cross-sectional side-view schematic of another embodiment of the present invention in which the parallel plates and desalination chambers are vertical.

FIG. 6 is a side-view schematic of a simple float valve for permitting water to leave the desalination chambers.

Claims

1. A desalination system, comprising: a heat source, which could be a solar collector, for boiling water to produce steam; anda set of parallel plates forming narrow chambers between the plates, which are sealed against ambient air, the steam chamber of which receives the steam and provides heat to the first desalination chamber by the condensation of steam on the parallel plate that separates the steam chamber from the first desalination chamber, which first desalination chamber evaporates water from seawater (or other aqueous solution) flowing as a film on one parallel plate and condenses fresh water on another parallel plate; anda series of desalination chambers formed between the other parallel plates, which desalination chambers use the heat of the condensation of water vapor from the previous desalination chamber to evaporate seawater flowing on one parallel plate and condenses the water vapor to fresh water on another parallel plate, each desalination chamber being at lower temperature than the previous desalination chamber; andan evaporation tray formed with the final parallel plate adjacent to the last desalination chamber wherein a film of seawater flows on the evaporation tray and removes heat from the desalination system by evaporation of water into the ambient air.

2. A desalination system of claim 1, wherein the parallel plates are sloped at angle to the horizontal and wherein the steam chamber is located between the lowest two parallel plates and wherein the desalination chambers are located between parallel plates above the steam chamber, and each successively higher chamber operates at successively lower temperatures and lower vapor pressures and wherein seawater flows down on the top of the lower parallel plate of each evaporation chamber and evaporates, and water vapor condenses on the upper parallel plate of each desalination chamber.

3. A desalination system of claim 2, wherein incoming seawater is heated by condensation of steam on the pipe containing the incoming seawater in the steam chamber in order to preheat the seawater before the seawater enters the first desalination chamber.

4. A desalination system of claim 2, wherein the higher vapor pressure of lower desalination chambers force the seawater to flow up to the next higher desalination chamber and wherein the seawater leaving the highest desalination chamber is pumped out to the evaporation tray.

5. A desalination system of claim 2, wherein float valves prevent seawater from flowing from one desalination chamber to the next higher desalination chamber, unless sufficient seawater is present, in order to prevent water vapor from flowing from one desalination chamber to the next.

6. A desalination system of claim 2, wherein constricted vent pipes bleed entrapped air from one desalination chamber to the next.

7. A desalination system of claim 2, wherein the underside of the upper parallel plate of each desalination chamber has attached fibrous cords, which collect condensed water by capillary attraction and deposits the water in troughs at the sides of the plates.

8. A desalination system of claim 2, wherein a steam control unit prevents water or steam from flowing from the boiler to the steam chamber if insufficient steam is available.

9. A desalination system of claim 5, wherein a u-shaped pipe is substituted for the float valve assembly wherein differential heights of seawater on each side of the u-shaped pipe prevent the flow of vapor from one desalination chamber to the next.

10. A desalination system according to claims 2 through 9, wherein a baffle plate is inserted between and parallel to the parallel plates of each desalination chamber, which baffle plate extends from the lower end to near the upper end of each desalination chamber in order to force the water vapor that evaporates from the bottom parallel plate of each desalination chamber to flow from the bottom parallel plate around the end of the baffle plate near the upper end of the upper parallel plate and then flow toward the lower end of the upper parallel plate so that the vapor sweeps entrapped air in the water vapor toward the lower end of the desalination chamber where the entrapped air is removed by the vent pipes of claim 6.

11. A desalination system of claim 10, wherein the baffle plates additionally serve as catch trays to capture condensed water drops that fall from the parallel plates immediately above the baffle plates.

12. A desalination system of claim 1, wherein the parallel plates are mounted vertically and wherein steam enters the chamber between the center two parallel plates and wherein seawater flows down the parallel plates on either side of the steam chamber on the opposite surface from the steam chamber and wherein the condensation of steam on the parallel plates provides heat to evaporate the seawater and wherein the evaporated water condenses on the next outwardly parallel plate and releases heat for the next outwardly desalination chamber and wherein the condensed fresh water flows down to the bottom of the desalination chamber to be collected for use.

13. A desalination system of claim 12, wherein the hot seawater and hot fresh water flowing down the parallel plates are collected at the bottom of the desalination chambers and flow through heat exchangers to heat the incoming seawater, which seawater then flows up through a pipe inside each desalination chamber and is further heated by condensation of water vapor on the outside of the pipe, and which heated seawater flows up to float-valve-controlled water dispensers that dispense seawater to the hotter parallel plate in the desalination chamber below.

14. A desalination system of claim 12, wherein float valves at the bottom of each desalination chamber prevent seawater and fresh water from exiting when insufficient water is present.

15. A desalination system of claim 12, wherein seawater dispensers cause cool seawater to flow as a film down the outside of the outer parallel plate on each side of the desalination unit for the purpose of removing the condensation heat of the last desalination chamber by evaporation of water in the ambient air.

16. A desalination system of claim 12, wherein separator plates are placed within each desalination chamber at the bottom to separate the fresh water from the seawater.

17. A desalination system according to claim 16, wherein the separator plates are elongated to extend to near the top of the desalination chamber in order to force the evaporating water vapor from the seawater side of the chamber to flow up around the separator plate and down the freshwater side of the chamber so that the vapor sweeps entrapped air in the water vapor toward the bottom end of the desalination chamber where the entrapped air is removed by vent pipes.

18. A desalination system according to claims 12 through 17, wherein the vertical parallel plates are replaced by vertically oriented cylinders placed concentrically so that the desalination system has cylindrical geometry.

19. A desalination system of claim 1, wherein an aqueous solution is produced by collection of water from the air by a hygroscopic material and wherein the aqueous solution replaces seawater in the desalination unit to be distilled to produce fresh water.

20. A desalination system of claim 1, wherein the heat source provides hot water or other hot fluid instead of steam to flow into the equivalent of the steam chamber to supply the heat to drive the system.