DE102006005099B4 - Desalination device - Google Patents

Abstract

Water desalination device with a solar collector as an evaporator with at least one trough-shaped parabolic or semi-cylindrical reflector (21, 29) and an absorber carrying a working medium arranged in its focal line (22, 30), the absorber being designed as a telescopic tube absorber (31), the inside diameter the telescopic pipe sections (32) of the pipe absorber (31) are dimensioned so differently that the telescoping is accompanied by a significant change in the flow rate of the working medium and salt water flows through the absorber as working medium and a collecting device is provided for its condensate.

Description

The invention relates to a water desalination apparatus according to claim 1.

From the DE 101 52 702 A1 a method and an arrangement for solar thermal desalination is known. In the focal line of parabolic trough mirrors, air is heated in heat-insulated pipes and blown from below into a reactor in which salt or brackish water is sprayed from above for evaporation. The generated steam is condensed in a cooling vessel, at the same time serving to preheat the salt water to be supplied.

For water heating various types of solar panels are known.

So revealed the US 42 39 033 A a solar collector with at least one trough-shaped parabolic or semi-cylindrical reflector and arranged in the focal line, a working medium leading pipe absorber whose outer surface is ribbed. Above the reflector, a transparent cover is arranged.

In the following shows the DE 31 01 186 A1 a solar collector with a working medium leading absorber comprising at least one dome-shaped, hemispherical or spherical wound hose.

In addition, from the EP 04 66 107 A1 a solar collector in at least approximately dome-shaped, hemispherical or spherical shape, which comprises a storage tank and this spaced enclosing transparent hood, wherein the storage tank directly serves as an absorber.

Furthermore, the shows DE 20 2004 002 535 U1 a double-walled ball / hemisphere collector with a tubular or smooth absorber surface made of plastic or metal. An inlet for a working medium opens into a gap between a transparent cover and the curved absorber surface. In the center of the absorber surface, a downpipe is provided as a drain for the working medium.

It is an object of the invention to provide a water desalination apparatus which has a high efficiency and can also be used for power and heat recovery.

According to the invention, this object is achieved by a water desalination apparatus having the features of claim 1.

With the telescoping of the tube absorber, so its change in length, is accompanied by a change in the flow rate of the working medium, which is located in the region of the reflector for heating. Furthermore, the cross sections of the pipe absorber through which the working medium flows are reduced, the largest cross section being associated with an inlet of the working medium, which is why the working medium experiences a relatively high heating and the solar collector has a high efficiency and works efficiently in a simple construction.

In an embodiment, the inner diameter of the telescoping pipe sections of the pipe absorber are dimensioned differently such that a significant change in the flow rate of the working medium is associated with the telescoping. The vaporizing working medium therefore has a high speed due to the energy conservation law of the flow of Bernoulli at the outlet of the Rohrabsorbers and is suitable for driving a downstream steam turbine, at the outlet of the condensed working fluid can be collected and fed again to the Rohrabsorber. Furthermore, behind the steam turbine, which drives, for example, a generator, a capacitor may be arranged.

In order to provide the largest possible surface area for heat transfer, at least the pipe section of the largest dimension has a ribbed outer surface. Of course, it is possible to provide all pipe sections with a ribbed or corrugated surface.

The pipe absorber can be double-walled and then leads a relatively small amount of the working medium between a transparent outer tube and an inner tube, which is why this is heated rapidly to a high temperature.

To provide a large heat transfer surface, at least one inner tube preferably has a ribbed outer surface. The serving as absorber inner tube is particularly black. Alternatively, a transparent knitted fabric through which the working medium flows is arranged between the inner tube and the outer tube. This, for example, plastic knitted fabric also causes an increase in the heat transfer surface. At the same time, the knitted fabric regulates the flow rate of the working medium.

So that the solar collector has a compact design, expediently runs the focal line within the reflector. Preferably, a translucent cover is disposed over the reflector. By the For example, made of plastic cover pollution of the reflector is reduced. In a further development, a plurality of reflectors are arranged side by side, the pipe absorbers are in fluid communication with each other. If the pipe absorbers are connected in series, the working medium is gradually heated and a high temperature can be achieved.

If the absorber is formed as a coiled tube, which of course can be replaced by a suitably shaped tube, the solar collector has a heat absorbing surface which is larger than its base. The frame determines the shape of the absorber, which never comes into contact with the frame over the entire surface, which is why heat losses through the frame without additional insulation are low and the solar collector has a high efficiency with a simple structure. The frame may for example be made of plastic or comprise a metal frame. Preferably, the frame is made of metal, for example using a laser-cut component or a wire. The individual components can be cut, for example, with a laser. It is also possible to make the frame from a metal wire.

Conveniently, a storage tank for the working medium is inserted into the frame. The storage tank is thus exposed to the heat radiation of the hose and the environment and the working fluid is heated before it is passed through the absorber.

Preferably, the storage tank made of a flexible plastic. Since the storage tank is held by the rack, it is not required to have high inherent stability.

Advantageously, the tube comprises a transparent outer skin and a dark, in particular black, inner skin. The transparent outer skin is an insulating layer to increase the efficiency of the solar collector.

In an embodiment, two absorbers are assembled into a correspondingly shaped hollow body. Accordingly, the two absorbers z. B. form a ball.

Another solar collector is designed to heat a relatively large volume of the working medium.

A solar collector for preheating is advantageously formed with the features of claim 15.

In the solar collector with a spaced from a transparent cover spanned hemispherical or lenticular absorber penetrates a coupled with a storage tank inlet pipe for the working medium as a riser the center of the absorber, so that in the existing between the cover and the absorber intermediate working medium evenly over the absorber is distributed and heated by this efficiently. A drain pipe for removing the heated working medium is inserted into the vertex of the cover.

The trained example as water working fluid is filled in the absorber and leaves it warmed up by the drain pipe, which has as inlet for the working fluid at least one, but preferably a plurality of peripheral bores immediately below the absorber. At the attached to the free end of the drain pipe plate from the bottom of the absorber.

In order to prevent a mixing of the inflowing through the inlet cold working medium with the already heated in the absorber warm working medium largely, on the one hand, the drain pipe is inserted into a bottom-mounted pipe and on the other hand, the inlet pipe is assigned a baffle. Of course, the tube has a much larger diameter than the drain pipe and ends below the absorber, so that the working fluid first reaches the pipe when it reaches a certain level and there insulating acts. Thus, the working medium is to heat without solar radiation, located inside the absorber, a heating element, which is electrically heated, for example.

The container used in the metal frame according to claim 10 can be filled with the working medium, which may also be water, and used as an absorber or reservoir. Of course, it is easily possible for a person skilled in the art to inexpensively manufacture individual parts of the metal frame, for example by means of laser cutting. So that the flexible container does not suffer any pressure-related damage in the filled state, it is inserted into the metal frame.

When filling the container, it inflates, deforming a helically wound flexible wire until the wire forms a metal frame surrounding and stabilizing the container. Of course, two interconnected spirals may be provided which engage over the container in its entire contour. Conveniently, the metal frame carries a hose wound thereon. The example filled with water hose is used for insulation.

To withstand the prevailing internal pressure, the pressurized container is preferably formed elliptical or lenticular.

In an embodiment, the inlet pipe opens into the overflow openings having serving as an absorber container and the one end of the drain pipe is disposed between the container and the cover. After the working medium has reached a certain level within the container made of a black film, it passes through the overflow openings in the outer skin of the container in an intermediate space formed between the container and the particular substantially hemispherical transparent cover for heating. The intermediate space leaves the working medium via the drain pipe, which is located approximately in the center of the cover. So that the working fluid does not escape uncontrollably from the intermediate space, the container is circumferentially sealed against the cover or the absorber.

Conveniently, the absorber and / or the container and the cover are mounted on a common plate, which in turn is arranged on an insulation.

In addition, a solar collector may advantageously be formed according to the features of claim 23.

The solar collector can be operated both with liquids, in particular water, as well as with gases and serves for desalination of water, wherein the resulting condensate is collected, and / or cooling of rooms due to the evaporation of the liquid working medium. The knitted fabric represents, on the one hand, a transparent thermal insulation and, with a corresponding darker, in particular black coloring, can be used as absorber since it causes an enlargement of the heat transfer surface and at the same time acts in a regulating manner on the flow rate of the working medium.

Of course, additionally or alternatively outer walls of the solar collector can be designed as an absorber. The knitted fabric is, for example, plate-shaped and installed in one or more layers. Is the made of glass (fibers) or plastic knitted fabric made transparent, results in a relatively large evaporation of the working medium, the associated space, eg. As a greenhouse, cools. In the case of a channel-shaped design of the fabric, the solar collector can be attached to a building facade or to a refrigerated vehicle in the manner of a jalousie for realizing cooling. In connection with a water desalination plant, a dome-shaped or channel-shaped condensate collecting device is arranged above the absorber, which collects the fresh water obtained by the evaporation and supplies it to a tunnel-shaped collecting container. The outside of the solar panel existing perforated rails are provided for holding the serving as thermal insulation fabric. By a corresponding shaping of the tissue, a relatively high strength is achieved and the solar collector can be used as a thermal insulator to save energy.

In a solar thermal desalination device at least one of the solar panels described above is used as an evaporator, wherein flows through the absorber salt water as the working medium and a collecting device for the. Condensate is provided.

In order to compensate for the advantages and disadvantages of individual solar panels, the solar panels are preferably connected in series via a pipeline for the salt water. Accordingly, the salt water is gradually heated and evaporated, with individual or all solar panels can be assigned to capture fresh water condensate.

Preferably, a spherical condenser is provided, in the center of which a vertical inlet and, to this end, a condensate outlet is inserted. Of course, the capacitor may also be channel-shaped or tunnel-shaped. Conveniently, the inlet is coupled to the pipeline. The inlet can be configured as single-walled or double-walled, wherein it is also conceivable for the inlet to have cross-sectional changes in its course and, for example, to be telescopic in order to be able to regulate the flow velocity. The condenser is preferably arranged downstream of the last of the series-connected solar collectors, so that the steam of the brine reaches the condenser at a maximum temperature, on the outer wall of which the condensate precipitates, which collects at the bottom and is discharged via the condensate drain.

Furthermore, alternatively, the working fluid may condense in a turbine.

The invention will be explained in more detail below with reference to several embodiments with reference to the accompanying drawings. It shows:

1 a schematic representation of a desalination device according to the invention with a plurality of solar panels connected in series, which serve as an evaporator,

2 a schematic representation of an advantageous solar collector,

3 a schematic representation of the solar collector after 2 on an exterior facade of a building,

4 a schematic representation of a desalination device with the solar collector after 2 .

5 a schematic representation of a second advantageous solar collector,

6 a schematic representation of a third advantageous solar collector and

7 a schematic representation of a fourth advantageous solar collector.

In the water desalination apparatus, brine flows as a working medium through an inlet 1 in a first solar collector, its absorber 2 one around a hemispherical frame 3 wrapped hose 4 includes. The frame 3 is designed as a metal frame and takes a storage tank 5 made of a flexible plastic for the salt water. In the center of a transparent cover 6 spanned absorber 2 go down a downpipe 7 from the hose 4 off, that with a pipeline 8th communicating in a floor slab 9 is admitted. The bottom plate 9 is thermally insulated and supports both the frame 3 as well as the efficiency increasing cover 6 of the solar collector. Due to the winding of the hose 4 as well as the shape of the frame 3 a uniform temperature of the salt water is achieved in a direction-independent positioning of the solar collector.

About the pipeline 8th The salt water enters a second solar collector, which also on a thermally insulated, a tank comprehensive bottom plate 10 is mounted and a transparent kalbkogelförmige cover 11 having a correspondingly shaped absorber 12 spans. The absorber 12 includes an outer wall 13 and a spaced inner wall 14 and leads in his thus formed gap 15 that via a bottom plate plate side inlet opening 16 inflowing salt water to be heated, via a in the center of the absorber 12 arranged downpipe 17 and the associated pipeline 8th get to a third solar panel. As the absorber 12 takes a relatively small amount of salt water, this is heated quickly to a high temperature. Below the absorber 12 In turn, a storage tank communicating therewith may preheat the salt water on the bottom plate 10 be arranged.

A third solar collector covers one with the pipeline 8th associated absorber 18 inside with a transparent cover 19 provided and designed as a bottom plate. The absorber 18 contributes to increase the heat transfer surface by a flow of salt water thermal insulation 20 , which is made of plastic. Instead of the cover 19 can also be provided a catcher for fresh water condensate.

About with the absorber 18 coupled pipeline 8th The salt water passes to a fourth solar collector, the two side by side, trough-shaped parabolic reflectors 21 comprising heat insulations on their backs and their focal lines within the reflectors 22 tube absorbers 23 . 24 are arranged, wherein a pipe absorber 23 consists of a smooth or ribbed pipe and the other pipe absorber 24 double-walled. Between an inner tube 25 and an outer tube 26 of the double-walled pipe absorber 24 is a traversed by the salt water transparent insulation 27 arranged. About the reflectors 21 extends a transparent cover 28 ,

A fifth solar panel over the pipeline 8th is connected to the fourth solar collector, also has a trough-shaped parabolic reflector 29 with one inside the reflector 29 extending focal line 30 along, along a telekopierbarer pipe absorber 31 is arranged, extending over the reflector 29 a transparent cover 33 extends. Due to the telescopic nature of the pipe absorber 31 This is easier to transport and install. The inner diameter of the telescopic pipe sections 32 of the pipe absorber 31 are dimensioned so differently that with the telescoping a significant change in the flow rate of salt water is accompanied. At an open outlet end of the pipe sorber 31 is a steam turbine connected to a generator 34 arranged, which is driven by the evaporated salt water.

The precipitated condensate is collected and passed through the pipeline 8th a feed 35 a spherical capacitor 36 fed, with the inlet in the center of the condenser 36 protrudes and causes a condensate drain 38 is provided.

The solar collector according to the 2 to 4 stands over a pipeline 39 With inserted pump 40 a storage container 41 for the formed as water working medium in communication, wherein the pipeline 39 into a distribution channel 42 flows through the water through openings 43 above several layers of a knitted fabric 44 got into the solar collector. Water that does not evaporate will have a return 45 in the reservoir 41 directed.

When arranging the solar collector on an external facade 46 a building serving as a greenhouse 47 is a fan 48 to create a knitted fabric 44 provided by flowing air flow, which promotes the evaporated water for cooling in the building or a room thereof, as by the arrows 49 is indicated.

For evaporating the water in a desalination device is the T-shaped arranged large-area knitted fabric 44 to 4 from a film serving as an absorber 50 covered. Here, the solar collector can be made buoyant.

The condensate produced by the evaporation is in a tunnel-shaped condensate trap 51 above the knitwear 44 collected and through a process 52 fed to a collection container.

The solar collector after 5 includes a lenticular container 61 as an absorber 53 is used and peripherally sealed to a substantially hemispherical transparent cover 54 is applied. The absorber 53 is made of a black flexible film 55 manufactured and surrounded on the outside by a stabilizing metal frame, which consists of a helically wound wire. In the absorber 53 an inlet pipe opens 56 for the working medium containing the absorber 53 inflated as it flows in. When inflating the absorber 53 nestles the metal frame on the outer wall and changes according to the size of the absorber 53 his form. The working medium passes over overflow openings 57 of the absorber 53 in a gap 58 between the cover 54 and the absorber 53 where it is at a certain level by one with a free end in the gap 58 protruding drainpipe 59 is derived. When emptying the absorber 53 this falls together and the metal frame also reduces its size, as its turns shift due to gravity. Inside the transparent cover 54 Hygrophilic materials can be provided to increase the evaporator surface, which has an advantageous effect in particular in the desalination of water.

According to the solar collector 6 is located below the transparent cover 54 a substantially hemispherical absorber 60 in the container made of a flexible material 61 is inserted circumferentially sealed. The container 61 is surrounded by a substantially consisting of a spirally wound flexible wire metal frame and is filled with air as a swim bladder. When inflating the container 61 nestles the metal frame on the outer wall and changes according to the size of the container 61 his form.

Through the inlet pipe 56 the working fluid enters a gap 58 between the cover 54 and the absorber 60 in which it is heated and at a certain level by the one with the free end in the intermediate space 58 protruding drainpipe 59 is derived.

To 7 it supports itself under the transparent cover 54 arranged hemispherical absorber 60 in its upper part on a plate 62 starting at the outlet pipe inserted into the center of the absorber 59 is attached, immediately below the absorber 60 several radially aligned holes 63 has, through which the working medium the absorber 60 leaves. The drainpipe 59 is located inside one on the thermally insulated floor 10 attached pipe 64 that's below the holes 63 ends. The inlet pipe 56 runs inside the absorber 60 as a riser parallel and spaced from the drain pipe 59 , The free end of the inlet pipe 56 is a baffle 65 assigned. Inside the absorber 60 there is an electric heating element 66 ,

LIST OF REFERENCE NUMBERS

1

inlet

2

absorber

3

frame

4

tube

5

storage tank

6

cover

7

downspout

8th

pipeline

9

baseplate

10

baseplate

11

cover

12

absorber

13

outer wall

14

inner wall

15

gap

16

inlet port

17

downspout

18

absorber

19

cover

20

Knitted

21

reflector

22

focal line

23

tube absorbers

24

tube absorbers

25

inner tube

26

outer tube

27

thermal insulation

28

cover

29

reflector

30

focal line

31

tube absorbers

32

pipe section

33

cover

34

steam turbine

35

Intake

36

capacitor

37

absorber

38

condensate drain

39

pipeline

40

pump

41

reservoir

42

distribution channel

43

openings

44

Knitted

45

returns

46

outer facade

47

building

48

fan

49

arrow

50

foil

51

Condensate collection device

52

procedure

53

absorber

54

cover

55

foil

56

supply pipe

57

overflow

58

gap

59

drain pipe

60

absorber

61

container

62

plate

63

drilling

64

pipe

65

baffle

66

heater

Claims (33)

Water desalination apparatus having a solar collector as evaporator with at least one trough-shaped parabolic or semi-cylindrical reflector ( 21 . 29 ) and one in its focal line ( 22 . 30 ), a working medium leading absorber, wherein the absorber as a telescopic tube absorber ( 31 ) is formed, the inner diameter of the telescopic pipe sections ( 32 ) of the pipe absorber ( 31 ) are dimensioned so differently that with the telescoping a significant change in the flow rate of the working fluid is accompanied and flows through the absorber salt water as the working fluid and a catcher is provided for the condensate. Water desalination apparatus according to claim 1, characterized in that at least the diameter in the largest sized pipe section has a ribbed outer surface. Water desalination apparatus according to claim 1 or 2, characterized in that the water desalination apparatus is a solar collector with at least one trough-shaped parabolic or semi-cylindrical reflector ( 21 ) and one in its focal line ( 22 ) arranged, a working medium leading absorber, the double-walled pipe absorber ( 24 ), is connected upstream. Desalination apparatus according to claim 3, characterized in that at least one inner tube ( 25 ) has a ribbed outer surface. Desalination apparatus according to claim 4, characterized in that between the inner tube ( 25 ) and the outer tube ( 26 ) a transparent thermal insulation ( 27 ) is arranged. Water desalination device according to one of claims 1 to 5, characterized in that the focal line extends within the reflector. Desalination apparatus according to one of claims 3 to 6, characterized in that a plurality of reflectors ( 21 ) are arranged side by side, whose tube absorber ( 21 ) are in fluid communication. Desalination apparatus according to one of the preceding claims, characterized in that above the reflector ( 21 . 29 ) a translucent cover ( 28 . 33 ) is arranged. Water desalination device according to one of the preceding claims, characterized in that a solar collector with a working medium leading absorber ( 2 ) having at least one dome-shaped, hemispherical or spherical wound hose ( 4 ), which takes on the form of the absorber ( 2 ) determining frame ( 3 ) is wound upstream. Desalination apparatus according to claim 9, characterized in that the frame ( 3 ) is made of metal, for example using a laser cut component or wire. Desalination apparatus according to claim 9 or 10, characterized in that in the frame ( 3 ) a storage tank ( 5 ) is used for the working medium. Desalination apparatus according to claim 11, characterized in that the storage tank ( 5 ) consists of a flexible plastic. Desalination apparatus according to claim 9, characterized in that the hose ( 4 ) comprises a transparent outer skin and a dark, especially black inner skin. Water desalination apparatus according to one of the preceding claims, characterized in that a solar collector with a spherical, hemispherical or lenticular absorber ( 60 ), which is covered by a transparent cover ( 54 ) is spanned at a distance and with a with an overflow ( 57 ) as a storage tank formed container ( 61 ) coupled inlet pipe ( 56 ) for the working medium and with a drain pipe ( 59 ) for the working medium, wherein the inlet pipe the absorber ( 60 ) and is inserted as a riser in the center of the absorber and the drain pipe in the apex of the cover is connected upstream. Water desalination device according to one of the preceding claims, characterized in that a solar collector with a spherical, hemispherical or lenticular formed as a storage tank absorber ( 60 ), which is covered by a transparent cover ( 54 ) is spaced spans and with a with the absorber ( 60 ) coupled inlet pipe ( 56 ) for the working medium and with a drain pipe ( 59 ) for the working medium, which as a riser in the center of the absorber ( 60 ) used drain pipe ( 59 ) the absorber ( 60 ) and at its free end a plate ( 62 ), at which the absorber ( 60 ) is supported, upstream. Desalination apparatus according to claim 15, characterized in that the drainpipe ( 59 ) at its upper end immediately below the absorber ( 60 ) at least one peripheral bore ( 63 ) having. Desalination apparatus according to claim 15 or 16, characterized in that the drainpipe ( 59 ) leaving the hole ( 63 ) in a bottom-mounted pipe ( 64 ) is used. Desalination apparatus according to claim 15, characterized in that the free end of the inlet pipe ( 56 ) a baffle ( 65 ) is assigned for the inflowing working medium. Desalination apparatus according to claim 15, characterized in that within the absorber ( 60 ) a heating rod ( 66 ) is arranged. Desalination apparatus according to claim 14, characterized in that the container ( 61 ) from a black film ( 55 ) is made. Desalination apparatus according to one of claims 14 to 20, characterized in that the container ( 61 ) peripherally against the cover ( 54 ) or the absorber ( 60 ) is sealed. Desalination apparatus according to one of claims 14, 20 or 21, characterized in that the absorber and / or the container ( 61 ) as well as the cover ( 54 ) are mounted on a common plate, which in turn is arranged on an insulation. Water desalination apparatus according to one of the preceding claims, characterized in that a solar collector with an at least one working medium leading absorber, which consists of a knitted fabric ( 20 . 44 ), is upstream. Desalination apparatus according to claim 23, characterized in that the knitted fabric ( 44 ) is arranged on a bottom plate of the solar collector, which is also designed as an absorber. Desalination apparatus according to claim 24, characterized in that the knitted fabric ( 44 ) made of glass (fibers), paper cells, metal or plastic. Desalination apparatus according to claim 24 or 25, characterized in that the knitted fabric ( 44 ) is arranged in one or more layers. Water desalination device according to one of claims 23 to 25, characterized in that above the absorber a condensate collecting device ( 51 ) is arranged, which communicates with a collecting container. Desalination apparatus according to one of the preceding claims, characterized in that the solar collectors are connected via a pipeline ( 8th ) are connected in series for the salt water. Water desalination apparatus according to one of the preceding claims, characterized in that a spherical condenser ( 36 ), in the center of which is a vertical inlet ( 35 ) and a condensate drain ( 38 ) is used. Desalination apparatus according to claim 29, characterized in that the feed ( 35 ) is single or double-walled. Water desalination apparatus according to one of the preceding claims, characterized in that the feed ( 35 ) Has cross-sectional changes. Desalination apparatus according to one of claims 30 to 31, characterized in that the feed ( 35 ) with the pipeline ( 8th ) is coupled. Water desalination apparatus according to one of the preceding claims, characterized in that the working medium is passed into a turbine.

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