WO2011003601A1

WO2011003601A1 - Heating and/or evaporating pipe, device for producing drinking water and device for heating fluid

Info

Publication number: WO2011003601A1
Application number: PCT/EP2010/004132
Authority: WO
Inventors: Martin Niedermaier
Original assignee: Martin Niedermaier
Priority date: 2009-07-09
Filing date: 2010-07-07
Publication date: 2011-01-13
Also published as: DE102009032482A1

Abstract

The invention describes a pipe that is designed for solar fluid heating and/or evaporation. The pipe has an elongated tubular body, which comprises a plurality of immersion sleeves arranged transversely with respect to the longitudinal extension of the tubular body. The immersion sleeves are designed to receive heat exchangers of solar collectors, in particular vacuum tube collectors, and protrude into the tubular body. The pipe is designed as a polygonal pipe, which comprises an upper and a lower wall section. When the pipe is in the installed state, the lower wall section is seated against the underside of the immersion sleeves. A channel-shaped wall section adjoins the lower wall section and forms a free space beneath the immersion sleeves that extends substantially over the entire length of the pipe and is situated at the bottom when the pipe is in the installed state. The invention further describes a device for producing drinking water, for example, from salt water or brackish water, by evaporation using such a pipe and a device for heating fluid using such a pipe.

Description

HEATING AND / OR EVAPORATING TUBE. DEVICE FOR OBTAINING DRINKING WATER AND DEVICE FOR

FLUID HEATING

The present invention relates to a tube which is designed for solar fluid heating and / or evaporation and has an elongated tubular body which comprises a plurality of immersion sleeves arranged transversely to the longitudinal extent of the tubular body, which are used to accommodate heat exchangers of solar collectors, in particular of vacuum tube collectors, are formed and project into the tubular body. Furthermore, the invention relates to a device for recovering drinking water from raw water, such. As salt or brackish water or chlorine, and to a device for fluid heating, in particular for use in solar air conditioning, directed.

Heating pipes and evaporation pipes of the type mentioned are in solar systems for heating fluid, such as water or other heat transfer fluid, or in devices for recovering drinking water from non-potable raw water, such. Salt and brackish water or chlorine water, used by evaporation by solar energy. Usually, the heating or evaporation tubes used have a circular cross-section, wherein the immersion sleeves project into the tubular body in such a way that the longitudinal axes of the immersion sleeves and the longitudinal axes of the tubular body intersect.

In order to align the solar collectors used in the immersion sleeves to the sun so that a maximum energy absorption is achieved in the sunlight, the solar panels usually have to be inclined to be ordered. As a result, the heat exchangers arranged at the ends of the solar collectors and projecting into the immersion sleeves likewise do not run horizontally but at an angle to the horizontal. In evaporation tubes, which are only partially filled with water, since the space remaining above the water level within the evaporation tube space for receiving the generated water vapor is required, this has the consequence that the heat exchangers of the solar collectors are with their free ends above the water level and thus contribute to the heating and evaporation of the water not or only very slightly. In the case of heating pipes which are completely filled with fluid to be heated, on the other hand, the diameter of the heating pipe must be selected to be very large in order to be able to receive the entire heat exchanger within the heating pipe with a circular cross section, which results in a correspondingly large amount of fluid within the heating pipe. Due to this large amount of fluid, it is often not possible to achieve sufficiently high heating of the fluid. If, however, the diameter of the heating tube is chosen correspondingly smaller in order to reduce the amount of fluid flowing within the heating tube, it is not possible to completely accommodate the heat exchangers within the heating tube.

For the reasons described thus the efficiency of the aforementioned evaporation and / or heating pipes is often unsatisfactory. Accordingly, the efficiency of devices for obtaining drinking water from raw water by evaporation is often unsatisfactory, or it must be supplied in addition to the solar energy still energy for heating the water in order to achieve a sufficient efficiency. The same applies to devices for heating fluid, as used for example in solar air conditioners.

It is an object of the present invention to provide a heating tube or an evaporation tube, which has an improved efficiency. Furthermore, corresponding devices for obtaining drinking water from raw water and a device for heating fluid are to be specified, which have an increased efficiency and in particular can be operated exclusively with solar energy.

Starting from a tube of the type mentioned above, the object concerning the tube is achieved according to the invention in that the tube is designed as a polygonal tube which comprises an upper and a lower wall section, that in the installed state of the tube the lower wall section on the underside of the immersion sleeves is applied and that adjoins the lower wall portion a channel-shaped wall portion through which a substantially over the entire length of the tube extending, in the installed state of the tube bottom side located free space is formed below the immersion sleeves.

A device according to the invention for the production of drinking water from raw water, such. For example, salt or brackish water or chlorine water, by evaporation comprises a raw water supply, an inventively designed evaporation tube for vaporizing the raw water supplied by solar energy, a plurality of in the immersion sleeves of the

Used in evaporating tube solar collectors and connected to the evaporation tube condenser for condensing the steam generated in the evaporation tube to drinking water. An inventively designed device for fluid heating comprises a supply unit for the fluid to be heated, a heating tube designed according to the invention for heating the supplied fluid by solar energy, a plurality of solar collectors inserted into the immersion sleeves of the heating tube and a discharge unit for the heated fluid from the heating tube ,

According to the invention, therefore, no tube with a circular cross-section but a polygonal tube is used as a heating tube or as an evaporation tube, which has a special optimized to increase the efficiency cross-sectional shape. This optimized, polygonal cross-sectional shape ensures that the immersion sleeves and thus the heat exchangers used in the immersion sleeves of the solar collectors are completely or at least almost completely washed by water or heat transfer fluid. At the same time, the amount of water or the heat transfer fluid can be kept low due to the special cross-sectional shape of the tube, so that a very effective heating of the water or the heat fluid is achieved. The mass of the tube used and of the fluid is thus kept very low according to the invention, which is necessary for efficient solar evaporation or heating.

Through the channel-shaped wall section is achieved that, despite the compact and compressed formation of the tube according to the invention a draining of the fluid and, when using the tube as an evaporation tube, the residues, such as the residual salt or chlorine, can be flushed out of the pipe.

With an inventively designed device for the production of drinking water, for example, from 100% raw water at least 95% germ-free and poison-free drinking water are generated. Depending on the amount of solar radiation and the size of the system, about 3 to 10 liters of drinking water per hour can be generated without the system having to be supplied with energy that goes beyond the solar energy. Furthermore, the optimized cross-sectional shape of the heating tube or evaporation tube, this can be adapted to any size system, without the amount of water per meter running pipe must be increased. Due to the optimized cross-sectional shape, the direct heat transfer surface of the immersion sleeves can be optimally utilized, with the entire insulated tubular body being additionally integrated into the heat transfer.

When using the heating tube according to the invention in combination with tube collectors, a heat transfer fluid can be heated very efficiently to temperatures above 100 ^° C., so that the operation of solar air conditioning systems with very high efficiency is possible.

According to an advantageous embodiment of the invention, the upper and lower wall sections are substantially parallel to each other. Since the solar collectors and also provided at the ends of the solar collectors heat exchanger usually have a circular cross-section and thus parallel outer walls, is achieved by the parallel arrangement of the upper and lower wall portion of the tube according to the invention that this at the upper or lower outside of the Thus, no space for fluid is provided in the area of the upper and lower wall sections above or below the immersion sleeves, so that the fluid is arranged in a concentrated manner between the individual immersion sleeves and at the same time essentially with the complete surface the immersion sleeves in contact. According to a further preferred embodiment of the invention, the channel-shaped wall section comprises one or more areas which extend transversely or obliquely to the lower wall section. In principle, the channel-shaped wall section can also have a curved shape, for example a U-shaped cross section.

Advantageously, the channel-shaped wall section connects to the end of the lower wall section towards the solar collectors.

By this arrangement it is achieved that the corresponding residues during evaporation due to gravity automatically accumulate in the free space formed by the channel-shaped wall portion. Even with heating pipes is ensured by this arrangement that the discharge of the fluid can be carried out completely, since the free space formed by the channel-shaped wall portion at the lowest point of the tube is.

According to a further advantageous embodiment of the invention in the installed state of the tube above the immersion sleeves, a substantially extending over the entire length of the tube evaporation chamber is arranged by a subsequent to the upper wall portion collector side further wall portion and by a subsequent to the lower wall portion Collector distant further wall section is limited. The further wall sections may be arranged obliquely or transversely to the upper and lower wall sections. As a result of this design, an evaporation space which can be adapted in size to the respective application can be provided above the immersion sleeves without the volume of the water flowing through the pipe having to be increased or reduced by enlarging or reducing the evaporation space. Regardless of the evaporation chamber, the immersion sleeves remain fully constantly or substantially completely disposed within the fluid, so that the efficiency of the tube during evaporation is always consistently high. The inventive design of the tube as a polygonal tube thus takes place a decoupling of evaporation space and fluid leading portion of the tube, so that both areas can be optimized independently of each other for their respective task.

Advantageously, the upper and / or the lower and / or the further wall sections have a flat surface. As a result, on the one hand, a simple and cost-effective production of the pipe designed according to the invention is possible, and on the other hand, the wall sections forming the fluid-conducting regions and the evaporation chamber can be formed optimally adapted to their tasks. Preferably, the immersion sleeves each extend substantially to the collector remote further wall portion and are in particular with their free ends on this. This ensures that, in particular in the case of an evaporation tube, the amount of water to be evaporated is heated by the solar collectors used in the immersion sleeves with maximum efficiency.

According to a further advantageous embodiment of the invention, the evaporation space is bordered by an upper wall section connecting the further wall sections in the installed state of the pipe upwards. The feeding of the water and the discharge of the generated

Steam can be achieved, for example, through openings in the upper wall section or through corresponding end openings at one or both ends of the tube. The size of the evaporation space can thus be achieved by a simple extension of the two further wall sections, which are used as the upper boundary of the evaporation zone. space are connected to each other via the upper wall portion, without the area containing the immersion sleeves and the fluid-carrying region of the tube would be affected. According to a further advantageous embodiment of the invention is in the region of the end face of the immersion sleeves between an extension of the upper wall portion, the collector remote further wall portion and an extension of the lower wall portion extending substantially over the entire length of the tube transport cavities for the fluid to be heated educated. This transport space is particularly relevant in the formation of the tube as a heating tube to allow the transport of the fluid to be heated by the heating tube and at the same time to ensure that the immersion sleeves with the heat exchangers of the solar collectors are still completely within the fluid to be heated.

In a device for recovering drinking water from raw water by evaporation may advantageously be arranged between the raw water supply and the evaporation tube, a preheating unit for preheating the raw water. As a result, the efficiency of the device can be further increased. In principle, although the preheating unit can be operated by means of additionally supplied energy. It is advantageous, however, that the preheating unit is operated by means of recirculated heat obtained within the device. For this purpose, for example, the evaporation tube can be connected to the condenser via a preheating tube, and the preheating tube can be passed through the preheating unit for preheating the raw water. The hot steam generated within the evaporation tube is thus passed through within the preheating tube through the raw water to be heated, whereby a preheating of the raw water takes place. In this way does not need to be introduced into the plant for preheating the raw water, no additional energy. If necessary, the energy of the preheating tube can also be used to heat liquids such as water or for heating or cooling.

Further advantageous embodiments of the invention are specified in the subclaims.

The invention will be described in more detail below by means of embodiments with reference to the drawings; in these show:

1 is a front view of an inventive device for recovering drinking water from raw water,

2 is a plan view of the device of FIG. 1,

4 is a perspective view of an evaporation tube according to the invention, as used in the device according to FIGS. 1 to 3, FIG.

5 is a detail view of the evaporation tube of FIG. 4,

Fig. 6 shows a cross section through the evaporation tube after

4, 7 shows a cross section through a modified embodiment of an evaporation tube according to the invention, FIG. 8 shows a cross section through a heating tube designed according to the invention, FIG.

9 is a side view of the heating tube according to FIG. 8 and FIG. 10 is a plan view of the heating tube according to FIG. 8.

1, 2 and 3 show an apparatus for recovering drinking water from raw water by evaporation with a raw water tank 1 shown schematically, in which the raw water is contained, which is connected via a raw water supply 2 with a water inlet 3 of a preheating unit 4. The preheating unit 4 extends substantially over the entire length of the device and has at its end opposite the water inlet 3 a water outlet 5, which is connected via a connecting line 6 with a float valve 7.

The output of the float valve 7 is connected to an inlet 8 of an evaporation tube 9 designed according to the invention, which extends parallel to the preheating unit 4 over the entire length of the device. At the opposite end of the inlet of the evaporation tube 9, an outlet 10 is provided, which is connected via a U-shaped connecting tube 11 with a steam inlet 12 of the preheating unit 4. The steam inlet 12 is connected via a arranged within the preheating unit 4 preheating tube 13 with a arranged on the opposite side of the preheating unit 4 Dampfau slass 14 connected. wherein the preheating tube 13 is inclined sloping from the steam inlet 12 to the steam outlet 14.

The steam outlet 14 of the preheating unit 4 is connected via a connecting pipe 15 to a conventional condenser 16, in which the water vapor supplied to the condenser 16 is condensed to produce drinking water.

The raw water to be evaporated is heated within the preheating unit 4 by the hot steam flowing through the preheating pipe 13, since the preheating pipe 13 is passed through the raw water within the preheating unit 4. Thus, the raw water supplied via the water inlet 3 of the preheating unit 4 is already increased in temperature as it exits the water outlet 5. Subsequently, the preheated raw water is supplied to the inventively designed evaporation tube 9, being ensured by the float valve 7 that the water level in the evaporation tube 9 is kept constant.

The evaporation within the evaporation tube 9 takes place by means of solar collectors 17 received solar energy, which is transmitted via arranged in the interior of the solar collectors 17 heat pipes 18 to end heat exchanger 19, which arranged in the evaporation tube 9 immersion sleeves 20 (see FIGS. 2 and 4 to 6 ) are used. The immersion sleeves 20 extend at regular intervals over the entire length of the evaporation tube 9 in each case substantially perpendicular to its longitudinal extent.

After this description of the basic structure of the apparatus for obtaining drinking water will be described below with reference to FIGS. 4 to 6 explains the optimized structure of the evaporation tube 9 according to the invention in detail.

From FIGS. 4 to 6, the special form of the evaporation tube 9 according to the invention can be seen as a polygonal tube with an optimized cross section. The evaporation tube 9 has a tubular body 47 with a wall structure comprising a plurality of successive wall sections, wherein an upper wall section 21 and a lower wall section 22 are provided which run essentially parallel to one another, the upper wall section 21 on the respective upper side 23 of FIGS Submersible sleeves 20 and the lower wall portion 22 abut the respective bottom 24 of the immersion sleeves 20. Adjoining the upper wall section 21 is a collector-side further wall section 25, which runs obliquely to the upper wall section 21 and extends substantially vertically upward in the installed state of the evaporation pipe 9. At the same time, a further wall section 26 remote from the collector joins the lower wall section 22, which together with the collector-side further wall section 25 and an upper wall section 27 connecting the two further wall sections 25, 26 delimit an evaporation space 28 of the evaporation tube 9.

As shown in FIGS. 4 to 6, the inlet 8 and the outlet 10 may be formed in the upper wall portion 27. However, it is also possible for the inlet 8 and the outlet 10 to be formed in the walls 29 delimiting the evaporation tube 9 at the end, as indicated in FIG. 4 and illustrated in FIGS. 1 to 3.

At the collector-side end of the lower wall section 22, a channel-shaped wall section 30 adjoins, which is offset from Celt regions 30 ', 30 "and 30'" consists and through which a arranged below the dip tubes 20 bottom-side space 31 is formed, which extends over the entire length of the evaporation tube 9.

As indicated in FIG. 6, the immersion sleeves 20 can each extend with their free ends as far as the collector-remote further wall section 26 and abut against it, as indicated by a dashed line 32. In this case, the immersion sleeves 20 may have up to their free ends a circular cross-section, so that the voltage applied to the collector remote further wall portion 26 inclined cross-section of the immersion sleeves 20 has an oval cross-sectional shape. However, it is also possible for the upper side of the immersion sleeves 20 to be beveled in the region of their free end, as indicated by a dashed line 33 and to be seen in greater detail from FIGS. 5 and 6. Furthermore, it is also possible that the free ends of the immersion sleeves 20 are cut at right angles, so that the free ends of the immersion sleeves 20 are arranged according to a dashed line 34 spaced from the collector remote further wall portion 26, as indicated in Fig. 6.

In all described embodiments of the immersion sleeves 20, however, due to the special cross-sectional shape of the evaporation tube 9, it is ensured that even when a small amount of water is introduced into the evaporation tube 9 substantially the entire surface of the immersion sleeves 20 is in contact with the water for heat transfer ,

For clarification, in FIG. 6, by way of example, possible water levels 35 with appropriate filling of the evaporation tube 9 with water are shown. posed. While the entire region of the evaporation tube 9 including the free space 31 located below the water level 35 is filled with water, the evaporation space 28 arranged above the water level 35 is free of water. As can be seen from FIG. 6, even with this small amount of water, the immersion sleeves 20 and thus also the heat exchangers 19 of the solar collectors 17 inserted in the immersion sleeves 20 are arranged essentially completely inside the water, so that virtually the completely absorbed solar energy is applied to the solar energy collector 17 Water can be discharged. It should be noted that also the area 45 between two adjacent immersion sleeves 18 is completely filled with water.

At the same time, the special cross-sectional shape of the evaporation tube 9 ensures that the evaporation space 28 located above the water level 35 is free of water, so that in particular the outlet 10 of the evaporation tube 9 is free of water, even if, for example, the evaporation tube 9 is filled with water low "skew" is mounted. If the size of the plant is to be extended by lengthening the evaporation tube 9 and a corresponding higher number of solar collectors 17, then only the evaporation space 28 must be increased, for example, by extending the two further wall sections 25, 26 upwards. However, this has no influence on the lower portion of the evaporation tube 9, so that the optimum amount of water per running meter can be maintained unchanged.

The trough-shaped free space 31 can serve as a flushing channel for draining off the brine (brine, chlorlake or other residual material) resulting from the evaporation. This can be done at one or both ends the evaporation tube 9 may be provided in the region of the channel-shaped wall section 30 drain valves, through which the brine can be discharged. For this purpose, for example, the upper part 36 of the device (see FIG. 3) can be designed to be pivotable relative to the lower part 37 via a hinge 38, thereby facilitating the discharge of the brine present in the free space 31. The tilting of the upper part 36 can take place, for example, via a tilting mechanism 39, in particular manually, for example with a hand crank 40. As can also be seen from FIG. 3, the lower part 37 of the device with wheels 41 can be designed to be mobile, so that the entire device can be transported.

For example, if a larger vaporization area of the water level 35 is required for certain applications, a modification of the evaporation tube 9 shown in FIG. 7 may be used. The modified evaporation tube 9 'differs from the evaporation tube 9 in that the upper wall section 21 does not bear against the upper side 23 of the immersion sleeves 20, but extends vertically upwards. At the upper wall portion 21, the obliquely extending further wall portion 25 connects. By this modification, the evaporation space 28 is enlarged in the horizontal direction, whereby a larger evaporation surface of the water level 35 is achieved. In principle, the upper wall section 21 can also be formed obliquely and the further wall section 25 can extend horizontally or vertically.

If a tube designed according to the invention is not required as an evaporation tube but as a heating tube, for example for a solar air-conditioning system, the evaporation space 28 can be dispensed with. A corresponding heating tube is shown in FIGS. 7 to 9. Similar or identical elements, as they have already been described in FIGS. 1 to 6, are provided in FIGS. 7 to 9 with the same reference numerals.

As can be seen from FIGS. 7 to 9, the heating tube 42 differs from the evaporation tube 9 essentially by the absence of the evaporation space 28 and by the fact that in the region of the front ends of the immersion sleeves 20 between an extension 21 'of the upper wall portion 21st in that the further away from the collector wall portion 26 and an extension 22 'of the lower wall portion 22 is a substantially over the entire length of the heating tube 42 extending transport space 43 for the guided from a front end of the heating tube 42 to its opposite end to be heated fluid is formed. In order to supply the fluid, an inlet 8 can again be provided at an end face of the heating tube 42, while at the opposite end there is again an outlet, not shown. Even with the heating tube 42 designed according to the invention, the immersion sleeves 20 are practically completely within the fluid 46 to be heated, so that an optimum efficiency for the heat transfer from the solar collectors 17 via the heat exchangers 19 and the immersion sleeves 20 to the fluid 46 to be heated is ensured. At the same time the amount of fluid to be heated 46 is significantly reduced by the special cross-sectional shape of the heating tube 42 compared to conventional heating tubes, whereby an increased efficiency is achieved.

The heating tube 42 also comprises a free space 31, formed by a channel-shaped wall section 30, below the immersion sleeves 20, which for example, serves as a drainage channel for the heat transfer fluid during maintenance. This can be drained, for example, via a drain valve provided on the drain valve 44.

LIST OF REFERENCE NUMBERS

1 raw water tank

2 raw water supply

3 water intake

4 preheating unit

5 water outlet

6 connection line

7 float valve

8 inlet

9 evaporation tube

10 outlet

11 U-shaped connecting pipe

12 steam inlet

13 preheating pipe

14 steam outlet

15 connecting pipe

16 capacitor

17 solar collectors

18 heatpipes

19 heat exchangers

20 immersion sleeves

21 upper wall section

21 'extension of the upper wall portion 22 lower wall portion

22 'extension of the lower wall section

23 Top of the immersion sleeves

24 Bottom of the immersion sleeves

25 collector-side further wall portion 26 collector farer further wall section 27 upper wall section

28 evaporation chamber

29 frontal walls

30 channel-shaped wall section

30 ', 30 ", 30'" regions of the channel-shaped wall section

31 free space

32 dashed line

33 dashed line

34 dashed line

35 water levels

36 upper part of the device

37 lower part of the device

38 hinge

39 tilting mechanism

40 winch

41 wheels

42 heating pipe

43 Transport room

44 drain valve

45 area of the pipe

46 fluid

47 tubular body

Claims

Sponsor claims

1. Pipe adapted for solar fluid heating and / or vaporization with an elongated tubular body (47), the one

Variety of transverse to the longitudinal extent of the tubular body (47) arranged immersion sleeves (20), which are adapted to receive heat exchangers (19) of solar collectors (18), in particular of evacuated tube collectors, and project into the rohrförmi- gene body (47)

characterized ,

the pipe (9, 42) is designed as a polygonal pipe comprising an upper and a lower wall section (21, 22) such that in the installed state of the pipe (9, 42) the lower wall section (22) on the lower side (24) of FIG Submersible sleeves (20) is present, and that adjoins the lower wall portion (22) has a groove-shaped wall portion (30) through which a substantially over the entire length of the tube (9, 42) extending in the installed state of the tube (9, 42 ) free space (31) located on the bottom side is formed below the immersion sleeves (20).

2. Pipe according to claim 1,

characterized ,

that in the installed state of the tube (9, 42), the upper wall portion (21) on the upper side (23) of the immersion sleeves (20) is present.

3. Pipe according to claim 1 or 2,

characterized ,

in that the upper and lower wall sections (21, 22) extend substantially parallel to one another.

4. Pipe according to claim 1, 2 or 3,

characterized ,

in that the channel-shaped wall section (30) comprises one or more regions (30 ', 30 ", 30"') which are transverse or oblique to the lower one

Wall section (22) extend.

5. Pipe according to at least one of the preceding claims,

characterized ,

in that the channel-shaped wall section (30) adjoins the end of the lower wall section (22) which faces the solar collectors (17).

6. Pipe according to at least one of the preceding claims,

characterized ,

that in the installed state of the tube (9, 42) above the immersion sleeves (20) a substantially over the entire length of the tube (9) extending evaporation chamber (28) is arranged, which by a to the upper wall portion (21) subsequent Kollek - Gate-side further wall portion (25) and by a to the lower wall portion (22) adjoining the collector remote further wall portion (26) is limited.

7. Pipe according to claim 6,

characterized ,

the further wall sections (25, 26) are arranged obliquely or transversely to the upper and / or lower wall sections (21, 22).

8. Pipe according to claim 4 or 7,

characterized ,

that the immersion sleeves (20) each extend substantially to the collector remote further wall portion (26) and in particular with its free ends abut against this.

9. Pipe according to claim 6, 7 or 8,

characterized ,

in that the evaporation chamber (28) is connected by an upper wall section (27) connecting the further wall sections (25, 26) in the

Installation state of the tube (9) is limited upwards.

10. Pipe according to at least one of the preceding claims,

characterized ,

that in the region of the free ends of the immersion sleeves (20) between an extension (21 ') of the upper wall portion (21), the collector distant further wall portion (26) and an extension (22') of the lower wall portion (22) is substantially over the entire length of the tube (42) extending transport space (43) for the fluid to be heated (46) is formed.

11. Pipe according to at least one of the preceding claims,

characterized ,

the upper and / or the lower and / or optionally the further wall sections (21, 22, 25, 26) have a flat surface.

12. Apparatus for recovering drinking water from raw water such. B. saline or brackish water or chlorine water by evaporation with a raw water supply (1, 2), an evaporation tube (9) according to one of the preceding claims for evaporation of the supplied raw water by solar energy, a plurality of in the immersion sleeves (20) of the evaporation tube (9) used solar collectors (17) and to the evaporation tube (9) connected to the condenser (16) for condensing the steam generated in the evaporation (9) steam to drinking water.

13. Device according to claim 12,

characterized ,

in that a preheating unit (4) for preheating the raw water is arranged between the raw water feed (1, 2) and the evaporating pipe (9).

14. Device according to claim 13,

characterized ,

that the evaporation tube (9) via a preheating tube (13) to the

Condenser (16) is connected and the preheating tube (13) for preheating the raw water through the preheating unit (4) is passed.

15. A device for heating fluid with a feed unit for the fluid to be heated (46), a heating tube (42) according to one of claims 1 to 11 for heating the supplied fluid (46) by solar energy, a plurality of in the immersion sleeves (20) of the heating tube (42) used solar collectors (17) and a discharge unit for the heated fluid (46) from the heating tube (42).