AN APPARATUS FOR PRODUCTION OF STEAM FROM AN AQUEOUS LIQUID

Abstract

An apparatus for production of steam from an aqueous liquid includes (a) a solar panel with a pliable, essentially impermeable, polymer membrane having an outer surface and an inner surface, wherein the outer surface is adapted to be directed towards the sun; a lattice structure adapted to support the inner surface of the polymer membrane; a backing, which together with the pliable polymer film, encases the lattice structure; an inlet for the aqueous liquid; an outlet for the steam produced, and (b) means for providing a vacuum connected to the outlet. The apparatus can be produced with few and relatively simple components thereby reducing the cost of the apparatus.

Claims

1. An apparatus for production of steam from an aqueous liquid, comprising a. a solar panel comprising i. A pliable, essentially impermeable, polymer membrane having an outer surface and an inner surface, wherein the outer surface is adapted to be directed towards the sun, ii. A lattice structure adapted to support the inner surface of the polymer membrane, iii. A backing, which together with the pliable polymer film, encases the lattice structure, iv. An inlet for the aqueous liquid v. an outlet for the steam produced, and b. means for providing a vacuum connected to the outlet.

2. The apparatus according to claim 1, wherein the solar panel further comprises an outlet for the treated aqueous liquid.

3. The apparatus according to claim 1, wherein at least a part of treated aqueous liquid is mixed with fresh aqueous liquid and conveyed to the inlet.

4. The apparatus according to claim 1, further comprising a heat exchanger connected to cool the treated aqueous liquid and to heat fresh aqueous liquid.

5. The apparatus according to claim 1, further comprising a mixing pump for mixing the fresh aqueous liquid and the treated aqueous liquid before it is introduced to the solar panel via the inlet.

6. The apparatus according to claim 1, wherein the polymer membrane is sealable connected to the bottom.

7. The apparatus according to claim 1, wherein the polymer membrane and the backing are prepared of the same type of material.

8. The apparatus according to claim 7, wherein the lattice structure comprises flow channels for the aqueous liquid as well as the steam produced.

9. The apparatus according to claim 8, further comprising a manifold in the upper part of the panel for distribution of the aqueous liquid in the flow channels.

10. The apparatus according to claim 1, wherein flow channels for the aqueous liquid comprises flow inhibiting elements for increase of the aqueous liquid surface and the corresponding vapor.

Description

SHORT DESCRIPTION OF THE DRAWINGS

[0019] In the following, exemplary embodiments of the device and the method according to the present disclosure will be described with reference to the drawings in which:

[0020] FIG. 1 shows an embodiment in which the solar panel is placed horizontally.

[0021] FIG. 2 depicts a frame structure with ribs and rods.

[0022] FIG. 3 shows a frame structure with ribs having flow channels.

[0023] FIG. 4 shows a horizontal embodiment with process equipment attached.

[0024] FIG. 5 depicts a cross sectional view of an embodiment of the solar panel.

[0025] FIG. 6 shows the frame structure of embodiment shown in FIG. 5.

[0026] FIG. 7 shows the embodiment of FIG. 5 with attached process equipment.

DETAILED DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 depicts an embodiment of the claimed subject matter in which the solar panel 1 is placed horizontally. The basic construction is composed of a lattice 2 illustrated on FIG. 2. The lattice comprises a number of ribs 3 distanced from each other by rods 4. The ribs are provided with lower and upper apertures suitable for allowing the flow of vapor and liquid, respectively. The lattice is provided with a first end section 7 arranged with an inlet 8 for an aqueous liquid and a second end section 9 arranged with an outlet 10 for the vapor produced. Furthermore a means for producing vacuum is provided in vapor connection with the outlet. The lattice together with the first and the second end sections are covered by a pliable, essentially impermeable polymer membrane 12.

[0028] Initially, the solar panel is provided with an aqueous liquid to be distilled. As an example, the aqueous liquid can be saline seawater. When a vacuum is provided to the solar panel, the polymer membrane will be tightly secured to the ribs and the polymer membrane will be bulging inwardly. The bulging will at least in some areas, depending on the sun height, result in the sun rays being directed perpendicular to the polymer membrane, which will increase the efficiency. The means for producing a vacuum lowers the pressure inside the solar panel, which in turn will lower the boiling temperature of the aqueous liquid. As the volume of the vapor is higher than the corresponding aqueous liquid, the vapor will flow out of the solar panel. The lower apertures in the ribs will ensure the aqueous liquid to flow freely in the solar panel and the upper apertures will allow the produced vapor to be distributed in the room above the liquid surface and eventually be directed out of the outlet.

[0029] The means for producing a vacuum may at least in the initial phase of the process be a vacuum pump. However, in a certain embodiment the vacuum is produced by condensing the vapor to distilled water. The condensation may be provided by heat exchanging with a cooler liquid, like seawater. The condensation will produce a suction effect, which after a certain process time may be sufficient to provide for the vacuum pressure in the solar panel. After a certain process time, an amount of water will have evaporated from the liquid source and a new portion may be added, either batch wise or continuously.

[0030] FIG. 3 shows a frame structure with ribs having flow channels. The lower liquid flow channels 5 provide for a free flow of aqueous liquid and the upper liquid flow channels 6 provide for a free distribution and flow of the vapor produced.

[0031] FIG. 4 shows an embodiment with process equipment attached. The process equipment includes a vacuum pump 13 for providing the initial vacuum in the solar panel 1. In addition a condenser 14 is provided which will condense the vapor to obtain a distillate product 15. The condenser may be cooled with an appropriate liquid like seawater. While the vacuum pump usually is needed in the starting phase to speed up the provision of the low pressure in the solar panel, the valve 16 may later on transfer the vapor to the condenser 14. In the vapor produced in the starting phase is usually not condensed.

[0032] The process equipment further includes a heat exchanger 17, a pump 18 and a valve 19. The pump 18 recirculates a part of the aqueous liquid that has been treated in the solar panel to the inlet. The proportion of recirculated liquid and fresh aqueous liquid 20 entering the solar panel is adjusted by the valve 19. The amount of fresh aqueous liquid 20 entering the solar panel is heat exchanged with the part of the treated aqueous liquid leaving the system in the heat exchanger 17. When the system has been operated for some time a steady state will be obtained, where the concentration of impurities is maintained at a constant level in the solar panel. When seawater is used as the aqueous liquid feed, the impurities will be sodium chloride. The treated liquid may be discharged or may be further processed to recover the sodium chloride crystals.

[0033] FIG. 5 shows a cross sectional view of an embodiment of a solar panel intended for inclined positioning and FIG. 6 shows the lattice frame used in the embodiment. The lattice includes ribs 3 distanced by plates 21. The plate 21 separates the solar panel in an upper compartment intended to be directed towards the sun and a lower compartment for transport of the cooler liquid. The ribs are provided with lower apertures 5 for transporting the cooler aqueous liquid and upper apertures for transporting the aqueous liquid being heated by the sun rays. The lattice also includes a lower end section 22 for transporting the cooler liquid from the back of the solar panel to the front side. The end section comprises channels for conveying the aqueous liquid from the lower apertures 5 on the back to the upper apertures 6 on the front side. Furthermore, the lattice includes an upper end section having an outlet for the vapor produced. Also provided is an inlet 8 for the aqueous liquid to be treated. The inlet is provided with a pipe, which extends below the surface of the aqueous liquid.

[0034] The embodiment shown in FIG. 5 and FIG. 6 is initially provided with a vacuum provided by a not shown pump connected to the outlet for the vapor 10. The relative low pressure in the solar panel will provide for a boiling of the aqueous liquid, which in turn will produce vapor. The evaporation will occur primarily in the upper layer of the liquid and on the side of the solar panel facing the sun. The evaporation will cool the aqueous liquid and the cooler aqueous liquid will be transported at the backside of the solar panel through the lower apertures and the lower end section to the front side of the solar panel. At the front side of the solar panel the aqueous liquid will be heated and thereby be raised towards the surface of the aqueous liquid. In this way a circulation is provided for inside the solar panel. Fresh aqueous liquid may be added batch wise or on a continuous basis to maintain essential the same level of the surface of the aqueous liquid.

[0035] FIG. 7 shows the embodiment of FIGS. 5 and 6 with in a continuous operation configuration. Furthermore, the system is provided with a combined generator and electrical motor 26. The combined generator and electrical motor 26 initially functions as a vacuum pump, which receives electrical power from the grid. After the start up phase, the pressure in the produced vapor is used to operate the generator, thereby producing electrical energy. The energy may be supplied the grid or may be used to operate the pump 18 or other kinds of equipment requiring electrical energy. Due to the energy savings the system may be operated a very low cost. As explained for the embodiment shown in FIG. 4, the vapor is condensed in the condenser 14 and the condensate is heat exchanged with the fresh aqueous liquid. The valve 19 and the pump 18 provides for an assisted circulation in the solar panel and at the same time maintains a steady state inside the solar panel.

[0036] FIG. 8 shows an embodiment of the solar panel in which the vapor produced is collected in a reservoir 27 in the upper part. When several solar panels are used together, the stream of the vapors may be collected and conveyed to the common pump means and/or condensation operation.