Solar distillation apparatus

• US 4,194,949 A
• Filed: 10/31/1977
• Issued: 03/25/1980
• Est. Priority Date: 06/15/1977
• Status: Expired due to Term

• Current Assignee: Virgil Stark
• Original Assignee: Virgil Stark
• Inventors: Stark, Virgil
• Primary Examiner(s): Dority, Jr., Carroll B.
• Assistant Examiner(s): Jones, Larry
• Application Number:
  US05/845,862
• Time in Patent Office: 876 Days
• Field of Search: 126/270, 126/271, 60/641, 203/DIG. 1, 202/180, 159/1 S, 350/179, 350/180, 350/211, 350/299
• US Class Current: 202/180
• CPC Class Codes: B01D 3/00 Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping evaporation in general, e.g. of liquids for gas phase reactions B01B1/005; gas chromatography B01D15/08; destructive distillation C10B; preparation of alcoholic beverages by distillation C12H6/02
• CPC Class Codes: C02F 1/14 using solar energy
• CPC Class Codes: F24S 23/30 with lenses
• CPC Class Codes: Y02A 20/124 Water desalination
• CPC Class Codes: Y02A 20/142 Solar thermal; Photovoltaics
• CPC Class Codes: Y02A 20/212 Solar-powered wastewater sewage treatment, e.g. spray evaporation
• CPC Class Codes: Y02E 10/40 Solar thermal energy, e.g. solar towers
• CPC Class Codes: Y02P 70/10 Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working
• CPC Class Codes: Y02W 10/37 using solar energy
• CPC Class Codes: Y10S 203/01 Solar still
• CPC Class Codes: Y10S 203/17 Saline water conversion
• CPC Class Codes: Y10S 203/21 Acrylic acid or ester

Abstract

According to one aspect of the invention, a system is disclosed for substantially continuous distillation of water which comprises a plurality of parallel distillation units each comprising series of fluid and preferably also Fresnel-type lenses. Water to be distilled is preheated by circulating it through the fluid lenses on which evaporated water vapor is condensed to produce distilled water. The quantity of water circulated in the lenses is many more times the quantity of water evaporated by the solar energy concentrated by the lenses and condensed per unit of time to allow the circulated water to carry off heat recuperated within the lenses and the system. The preheated water circulated through the lenses is discharged into a central container in which the foci of the fluid and Fresnel-type lenses are located. Secondary containers are provided to receive overflow from the central container since preheated water may be discharged into the central container faster than it is being evaporated. Preferably heat exchangers having a heat exchange fluid therein are provided in the secondary containers to recover heat from the water therein. This system also may include or be combined with turbines and or a separate solar energy concentrator and collector used to superheat the heat exchange fluid and also preferably to heat excess water vapor removed from the distillation system and convert it to superheated steam and/or to externally condense the excess water vapor.

Claims

1. Apparatus for distillation of liquids using solar energy comprising:

first container means for containing a liquid to be distilled;

second container means for containing distilled liquid;

fluid lens means located above said first container means for concentrating the solar energy in at least one focus in said first container means to assist in the evaporation of said liquid therefrom, said fluid lens means defining an enclosure through which liquid to be distilled is passed and a planar lower surface extending at an angle with the horizontal and having a lower end disposed above said second container means, said planar surface being operative to condense evaporated liquid vapor thereon and transfer at least in part to said liquid being passed through said enclosure the heat of condensation released by condensing liquid vapor, whereby a substantial portion of the released heat of condensation is recovered, said planar surface being further operative to discharge condensed liquid vapor from said lower end into said second container means; and

means for passing the liquid to be distilled through said enclosure, said means for passing and said fluid lens means cooperating to discharge into said first container means said liquid to be distilled which has been passed through said enclosure at a rate which exceeds the rate at which said liquid is evaporated from said first container means such that the temperature of the liquid passed through said enclosure is maintained below the temperature of the evaporated liquid vapor.

2. The apparatus recited in claim 1, wherein said first container means includes a plurality of containers, a first container receiving the liquid being discharged from said fluid lens means and at least one other container operative to receive liquid from said first container, said focus of said fluid lens means being located in said first container.

3. The apparatus recited in claim 2 and further comprising first heat exchange means in said other container operative to remove heat from the liquid therein.

4. The apparatus recited in claim 2 and comprising a plurality of first container means, a plurality of second container means, a plurality of fluid lens means and a plurality of said means for circulating liquid all arranged to form a composite distillation system comprising a plurality of said apparatuses adjacently arranged and including means for interconnecting first containers of said apparatus, means for interconnecting other containers of said apparatus and means for interconnecting second container means, which comprise single common containers for each two of said apparatuses which are adjacent each other, each of said common containers being located between adjacent apparatuses and being operative to receive and contain condensed vapor from both of said two apparatuses.

5. The apparatus recited in claim 2, wherein said at least one other container is operative to store heat in the liquid therein for use during periods of reduced sunshine or without sunshine.

6. The apparatus recited in claim 3, wherein said first heat exchange means includes a heat exchange fluid to which the heat removed from the liquid is transferred, said apparatus further comprising turbine means and means for supplying said fluid to said turbine means from said first heat exchange means.

7. The apparatus recited in claim 6, and further comprising an additional solar energy system for converting solar energy to heat and second heat exchange means, said additional system including means providing heat to said second heat exchange means and means supplying said fluid to said second heat exchange means upstream of said turbine, said second heat exchange means being operative to transfer heat from said additional system to said fluid, and said apparatus also including means supplying said fluid from said second heat exchange means to said turbine.

8. The apparatus recited in claim 7, wherein the liquid is water, and further comprising third heat exchange means and means providing heat from said additional system to said third heat exchange means, said apparatus further comprising means for compressing water vapor, means for removing water vapor from said apparatus and supplying it to said means for compressing, and means for supplying compressed water vapor from said means for compressing to said third heat exchange means, said third heat exchange means being operative to transfer heat from said additional system to the compressed water vapor to produce steam.

9. The apparatus recited in claim 8, wherein said additional system includes elongated lens means and an elongated collector located at an elongated focus of said elongated lens means, said collector including at least two conduits, an inner conduit being located in another conduit, said apparatus further comprising means communicating said inner conduit serially with said third heat exchange means and thereafter with said second heat exchange means, said inner conduit being located at the elongated focus and carrying a high boiling temperature fluid having a boiling temperature greater than about 150°

C.

10. The apparatus recited in claim 8 and further comprising an additional turbine and means supplying said steam to said additional turbine.

11. The apparatus recited in claim 10, wherein the liquid is salt water and said apparatus further comprises means for electrolysizing salt water to produce sodium and chlorine from salt-rich salt water remaining after evaporation of at least some water from said first container means, both of said turbines producing electricity and providing at least part of the electrical energy required to electrolyze the salt water.

12. The apparatus recited in claim 10 and further comprising means for condensing steam discharged from said additional turbine using water to be distilled to produce additional distilled water, said means recuperating most of the heat of condensation of the condensing steam and transferring it to the water to be distilled.

13. The apparatus recited in claim 9 and further comprising means communicating said another conduit with said first container means.

14. The apparatus recited in claim 9, wherein the elongated lens means of the additional system includes at least one fluid lens.

15. The apparatus recited in claim 9, wherein the elongated lens means of the additional system includes at least one Fresnel lens.

16. The apparatus recited in claim 1 wherein the liquid is saltwater and further comprising means for recovering heat from the concentrated brine removed from the container means from time to time.

17. The apparatus recited in claim 1 and further comprising means for recovering heat from the condensed liquid.

18. The apparatus recited in claims 1 wherein the liquid is water and further comprising means for removing water vapor from said apparatus and means for externally condensing the removed water vapor to produce distilled water.