EP3333507A1 - Evaporator device - Google Patents

Abstract

The invention relates to an evaporator device comprising at least one liquid reservoir and at least two evaporator tubes.

Description

The invention relates to an evaporator device comprising at least one liquid reservoir and at least two evaporator tubes connected in parallel. The evaporator device is intended in particular for use in refrigerating machines, which preferably directly cool a gas-filled space.

For the evaporation of refrigerants, tube or tube bundle heat exchangers or plate heat exchangers are typically used in compression refrigeration. Plate heat exchangers are usually designed as flooded evaporator, in which move the vapor bubbles by their buoyancy and usually supported by a forced flow through the heat exchanger. Chillers with flooded evaporator usually have on the low-pressure side a container in which liquid refrigerant with a gas or vapor superposition is maintained under saturated steam conditions. The pressure in this container is typically maintained at a certain value, which is determined by the required temperatures in the space to be cooled.

In the case of tube or shell and tube evaporators, the refrigerant is usually trickled from outside onto a pipe with the aid of a feed system or they are also designed as flooded evaporators. Tube heat exchangers are also known in which the refrigerant evaporates in a horizontal or nearly horizontal or slightly inclined tube within a forced flow, wherein the tube heat exchangers can be formed from a plurality of juxtaposed, connected and serially flowed through tubes. Such a device is for example from the WO 2007 115 877 known. Heat pipes usually have a low flow resistance and a good heat transfer, but are present as a closed device with typically low expansion.

A disadvantage of the known from the prior art devices that flooded evaporator or tube or tube evaporator, in which the evaporation takes place within the tube, have a very small cross-sectional area for the flowing vaporized vapor stream, whereby the pressure losses are very high or a vapor movement is strongly inhibited by free convection. In addition, the liquid layer to be evaporated on the heat transferring surface is relatively thick, thereby disadvantageously increasing the thermal resistance.

Although sprinkled shell and tube heat exchangers have the advantage of a large free cross-sectional area for the vapor stream and thinner liquid layers, they do require a pressure booster to convey unevaporated liquid over the tube bundle and re-trickle. Both systems therefore have a low power density without pressure boosting devices for flow generation.

For heat pipes, the refrigerant can not escape from the heat pipes, as this would immediately lead to dehydration. Thus, the refrigerant can not participate in the refrigerant circuit in a refrigeration system. In addition, their small heat-transmitting surface due to the small spatial extent is not sufficient for the heat absorption in a refrigeration system. Especially in refrigeration systems, which directly cool a gas, a large area is needed because of the large heat resistance in the gas. Therefore, heat pipes are not suitable for use as evaporators in refrigeration systems.

Accordingly, it is an object of the present invention to provide an evaporator apparatus which does not have the disadvantages and shortcomings of the prior art, which reduces pressure losses within a refrigeration system and reduces the thermal resistance, so that the power density of the refrigeration system is increased, the operation of such apparatus in particular without pressure booster, such as a pump should be possible.

According to the invention an evaporator device is provided to solve the problem comprising at least one liquid reservoir and at least two substantially parallel evaporator tubes, wherein the evaporator tubes have a capillary structure and the liquid reservoir is disposed below the evaporator tubes and is liquid and / or vapor-conducting in communication with the evaporator tubes.

It is preferred for the purposes of the invention that the evaporator tube is preferably referred to synonymously as a vertical tube. Furthermore, the evaporator device is preferably also referred to as an evaporator. The term "connected in parallel" can preferably also be understood as "parallel in terms of flow" and, in the context of the invention, preferably means that a flow flows primarily simultaneously through the at least two evaporator tubes. In particular, a fluidic parallelism differs from one behind the other flowing through two tubes. The term "substantially" is not unclear to a person skilled in the art, since a person skilled in the art knows that a fluidic parallelism does not require strict geometric parallelism, but preferably means that the flow flows through the evaporator tubes substantially simultaneously. These are connected in parallel in the context of the invention, wherein the concept of parallel connection is known to those skilled in electrical engineering. In contrast to electrical engineering, there need not be strict parallelism in the invention, since the material flow in the pipes connected in parallel may well be of different sizes. The parallel connection of the evaporator tubes may preferably also mean that the tubes are also geometrically substantially parallel, but this geometric parallelism is not a prerequisite for the fluidic parallel connection of the evaporator tubes.

It is preferred for the purposes of the invention that the evaporator consists of at least one liquid reservoir and at least two fluidically connected in parallel vertical tubes, which connect to the liquid reservoir. It is particularly preferred according to the invention that the liquid reservoir is in communication with the evaporator tubes in such a way that liquids, gases or steam can pass the connection between the evaporator tube and the liquid reservoir.

In a preferred embodiment of the invention, the evaporator device comprises a steam passage for the passage of a steam flow in the interior of the evaporator tubes. It is preferred that the steam duct is formed inside the evaporator tubes, wherein the term "steam duct" in the sense of the invention preferably describes an area inside the evaporator tubes, through which gas or steam can flow and / or be passed.

In a preferred embodiment of the invention, the liquid reservoir is completely or substantially completely filled with a liquid, wherein the average person skilled in the art knows that substantially complete filling technically produces the same effect as a complete filling and that a substantially complete filling due to environmental influences , For example, by evaporation or loss of fluid can result from a complete filling.

It is particularly preferred that the liquid is a refrigerant, preferably water, ethanol or ammonia. The average person skilled in the art knows that water is the chemical compound having the empirical formula H2O, ethanol is the monohydric alcohol having the empirical formula C2H6O and ammonia is the chemical compound having the empirical formula NH3, these compounds being used as natural refrigerants in the Nature happen. It is preferable that the refrigerant is capable of transporting heat energy, preferably taking in heat at low temperature and low pressure, and releasing heat at higher temperature and higher pressure. An advantage of the use of natural refrigerants is that they do not release chlorofluorocarbons when used as a working medium and thus do not contribute to the depletion of the ozone layer and to promote the greenhouse effect.

A preferably particularly good transport of liquids, gases or steam from the liquid reservoir into the evaporator tubes can be achieved in a preferred embodiment of the invention in that at least one evaporator tube protrudes into the liquid reservoir. The term "projecting" in the sense of the invention preferably means that a lower end of an evaporator tube is immersed in the liquid which is located in the liquid reservoir. This immersion may be such that an opening of the evaporator tube, which preferably forms the lower end of the tube, is preferably completely or partially covered by the liquid in the liquid reservoir, it being particularly preferred if the opening of the evaporator tube is so immersed in the liquid, that the opening is completely in the liquid. In particular, will characterized the liquid and / or vapor-conducting connection between the liquid reservoir or the liquid in the liquid reservoir and the evaporator tube is formed. For the purposes of the invention, it is particularly preferred if a part of the liquid in the liquid reservoir comes to stand in the evaporator tubes, ie that in particular a lower region of the evaporator tube is filled with liquid. For the purposes of the invention, this situation is preferably referred to as partially flooded evaporator tube. It is particularly preferred for the purposes of the invention that the evaporator tubes, which preferably have a capillary structure, can be extended into the liquid reservoir.

The liquid reservoir is preferably horizontal or nearly horizontal. This means according to the invention that its bottom surface is on a substantially straight plane so that the surface of the liquid reservoir or the surface of the liquid reservoir located in the liquid reservoir preferably reflects the straight plane on which the device is located. The term "essentially" is not unclear to a person skilled in the art, because the person skilled in the art knows that refrigeration systems are advantageously to be set up on level substrates. It is particularly preferred for the purposes of the invention that the evaporation takes place from the liquid surface, i. that the evaporation effect in an upper region of the liquid in the liquid reservoir comprising the surface of the liquid, is particularly strong.

In a preferred embodiment of the invention, the evaporator tubes are arranged substantially perpendicular to the liquid reservoir. It may also be preferred according to the invention that the evaporator tubes include an angle α with the liquid reservoir, wherein the angle α is in the range of 30 to 90 °, particularly preferably 45 ° or 90 °. This preferred arrangement of the vertical tubes with respect to the liquid reservoir represents a significant departure from the prior art, according to which in compression refrigerators, for example, an angle of inclination is less than 5 °. For the purposes of the invention, it is preferred that the angle between an upper end of the liquid reservoir, which can be, for example, an upper imaginary, preferably plane, end plane of the reservoir, and the side walls of the evaporator tubes is formed. For example, a straight line lying in the final plane and a straight line, preferably arranged in the vapor direction and lying parallel to it, within a side wall of the evaporator tube form the legs of the angle α. Especially for large evaporator devices, it may be advantageous to arrange the evaporator tubes not vertically, but at an angle of inclination α to the liquid reservoir in order to support the capillary effect by the preferably oblique arrangement.

In a preferred embodiment of the invention, the capillary structure is formed by a structured surface and / or a capillary material, the capillary structure comprising materials selected from a group comprising sintered particles and / or chips, preferably metal, glass fiber fabric, structures having narrow flow cavities such as metal sponges, incised, pressed on, soldered and / or welded on channels and / or a combination thereof. It is particularly preferred for the purposes of the invention that the evaporator tubes are preferably coated on the inside with a structured surface, which advantageously causes capillary effects, whereby the liquid in the liquid reservoir is pulled up the walls and forms a thin film with a large evaporation surface.

The term "capillary effect" in the context of the invention preferably designates the behavior of liquids in narrow tubes, gaps or cavities in solids, which are preferably referred to as capillaries. Capillary effects are based on the surface tension of liquids and the interfacial tension which forms between a liquid and a solid surface, whereby advantageously liquid columns can form in capillaries contrary to the force of gravity due to capillary effects. Tests have shown that, in particular, capillary structures formed from structured surfaces within vertical evaporator tubes have good capillary action properties, especially when they are incised by particles or chips, preferably metal, incised, pressed, soldered or welded on small channels, as well as Glass fiber fabric or other structures with narrow flow cavities such as metal sponges are made. Soft structures, such as glass fiber fabric, for example, via a spiral under tension to the inside an evaporator tube are pressed or present in the interior of the evaporator tubes.

Due to the capillary action of the capillary structure, in particular the structured surface and / or the capillary material, which is preferably arranged in the evaporator tubes, the refrigerant is transported in a thin film upwards into the evaporator tube. The spatial direction "upwards" in the sense of the invention preferably describes the direction of space pointing away from the liquid reservoir, which points in the direction of a vapor withdrawal. By transporting the liquid or the refrigerant from the liquid reservoir, a thin film which is preferably formed over a large area and which is similar to a film that forms during the active external irrigation of pipes is formed within the evaporator tubes. Due to the formation of the thin film from the refrigerant advantageously remains a sufficiently large cross section within the evaporator tubes for the steam flow in the tube interior free. In addition, advantageously, the heat transfer resistance through the thin film is minimized. For the purposes of the invention, a thin film is preferably a film whose cross section leaves the predominant flow cross section of the tube free. The remaining for the steam flow cross-section of the evaporator tube is preferably referred to as "steam gate" in the context of the invention. Unevaporated refrigerant is advantageously redistributed over the surface via the capillary action of the tube surface. For this purpose, in contrast to known systems and devices of the prior art, no additional energy is needed. The evaporation inside the tubes allows for direct heat absorption from the environment around the tubes without the need for extra energy or redistribution. Thus, the present invention represents a departure from the known state of the art, in which the experts assumed that a redistribution of the unneeded refrigerant would not be possible without a further supply of energy.

In a further embodiment of the invention, it is preferred that the structured surface is firmly connectable to the evaporator tubes. This means in the context of the invention that the structured surface can be connected to the evaporator tubes and that during normal operation of the evaporator device non-detachable connection between the inside of the evaporator tube and the material of the structured surface is made. For the purposes of the invention, it is preferred if this connection, which is not detachable in normal operation, is formed by the joining methods sintering, scoring, pressing, soldering and / or welding, wherein other joining methods known to the person skilled in the art are also conceivable.

In an alternative preferred embodiment of the invention, the capillary material is detachably connectable to the evaporator tubes. This is especially the case when the capillary structure is formed by the capillary material. In the case of capillary structures not fixedly connected to the evaporator tubes, such as glass fiber fabric, extension of the evaporator tube into the liquid reservoir can be realized without simultaneous introduction of the evaporator tube thereto, for example, by placing part of the capillary material in the liquid in the liquid reservoir , reaches into or dives into it. By this type of extension, for example, a part of the capillary structure can be wetted even when the liquid reservoir is not completely filled, whereby advantageously still a good refrigerant transport is made possible in the evaporator tubes up.

In a preferred embodiment of the invention, the evaporator tubes comprise brass and / or copper. Tests have shown that copper pipes are particularly suitable as evaporator tubes in the sense of the invention, since they have a high thermal conductivity for the heat transport. In addition, these can be processed well, especially with each other. Brass pipes have the advantage of a strong corrosion resistance and can be combined particularly easily with copper parts, for example by soldering. It may also be preferred according to the invention that the evaporator tubes comprise aluminum. Aluminum has similar advantages, but is more difficult to combine in the long term with the aforementioned materials. An embodiment of the invention in which the evaporator device comprises aluminum is therefore particularly preferred when substantially all of the refrigeration system or subcomponents are made substantially entirely of aluminum.

In a preferred embodiment of the invention, an inner diameter of the evaporator tubes is less than 35 mm, preferably less than 30 mm and particularly preferably less than 27 mm. In this preferred embodiment of the invention, vapor bubbles can form in the liquid reservoir or in the preferably partially flooded evaporator tubes which can not rise above the preferred diameter in such a way that the liquid is pushed along a substantial part of the evaporator tube. As a result of the preferably substantially completely filled state of the liquid reservoir, it is preferably possible for liquid to be forced into the preferably vertical evaporator tubes in a surge-like manner, as a result of which an elevated fill level in the evaporator tubes temporarily arises. Due to the preferred inner diameter of the evaporator tube, the vapor bubbles can rise in the evaporator tubes until they burst and / or slowly flow past the liquid to be vaporized and pushed in front of the vapor bubbles. As a result, the evaporator tubes are advantageously preferably cyclically wetted from the inside with liquid, which can form a large, thin liquid film on the inside of the evaporator tubes particularly fast. Another advantage of the invention is that the height to which the evaporator tube is wetted with the liquid as well as the wetting rate, at the same time substantially increased compared to the simple wetting by the structured surface.

In a preferred embodiment of the invention, an inner diameter of the evaporator tubes is less than 20 mm, preferably less than 16 mm and particularly preferably less than 13 mm. If the evaporator tubes are designed with such a preferred inner diameter, the amount of fluid delivery through the vapor bubbles can advantageously be increased again. At the same time, for soft-structured materials with capillary action, such as glass fiber fabric, the advantage that this at the preferred diameters of this embodiment of the invention without an additional stiffening and / or pressing structure, such as the above-mentioned spiral, on the insides of the evaporator tubes stick, especially if it is voluminous capillary materials.

In a preferred embodiment, there is a direct spatial contact between the liquid reservoir and an environment of the evaporator device, said spatial contact preferably represents a thermal contact between the liquid in the liquid reservoir and the environment. This results advantageously from the fact that no heat transfer inhibiting insulation layers must be built around the liquid reservoir. For the purposes of the invention, it is particularly preferred that the environment is to be cooled, which is why it is also possible to speak of an "environment to be cooled" or a "cooling space". The term "spatial contact" in the sense of the invention preferably means that two objects are arranged next to one another and / or in the immediate vicinity of one another. In the present case, the spatial contact is preferably formed by the fact that the liquid reservoir and / or its outer walls directly adjacent to an environment, which preferably represents a gas volume, wherein a heat exchange between the liquid reservoir and / or its outer walls and the environment is made possible in the context of the invention is preferably referred to as "thermal contact".

It is preferred for the purposes of the invention to arrange the evaporator device in a space to be cooled so that the liquid reservoir is in direct thermal contact with the environment to be cooled. Advantageously, this further increases the above-described effect of the liquid delivery, so that the vapor bubbles, which are preferably formed deep in the liquid reservoir, can also convey liquid into the evaporator tubes, even if the liquid reservoir is not almost completely filled with liquid. A particular advantage in this case is that then the liquid reservoir can contribute to the evaporation of the liquid.

In a preferred embodiment, the evaporator tubes comprise a polygonal channel, wherein it is particularly preferred that the polygonal channel comprises plates which at a minimum distance have a maximum spacing of 5 to 15 mm, preferably 8 to 12 mm, particularly preferably 10 mm. It is preferred for the purposes of the invention that the evaporator tubes preferably comprise two plates which together form a wide channel and at the outer edges with each other are connected. This connection can be made, for example, directly or by a further plate. The depth of the channel according to the invention is preferably referred to as the distance between the plates and the width of the channel preferably refers to the width of the above-mentioned plates. It is particularly preferred that said numbers do not refer to the width of the plates, but preferably to their spacing, ie in particular the channel depth. In particular, this preferred embodiment involves the use of angular channels rather than tubes. Tests have shown that especially rectangular channels are particularly well suited. The preferably formed channels can have a capillary structure, for example a structured surface with capillary action, on one or more inner surfaces. It has been found that optimum distribution of refrigerant by means of vapor bubbles is made possible when a distance between the plates, which preferably represent the largest area of the rectangular channel, is a maximum of 5 to 15 mm, preferably a maximum of 8 to 12 mm, particularly preferably a maximum 10 mm.

In a preferred embodiment, the evaporator device comprises a feed system with outlet openings for the delivery of refrigerant to the evaporator tubes, the feed system preferably being arranged above the evaporator tubes. It is particularly preferred according to the invention to provide a delivery system, which is preferably located higher than the liquid reservoir. It is also preferred that the task system includes outlet openings to distribute from above refrigerant to the preferably vertical evaporator tubes and / or give up. As a result, liquid can be distributed particularly quickly from an upper region of the evaporator device over the preferably entire area of the evaporator tubes. This can be achieved, for example, by utilizing gravity, for example when the liquid is dispensed from a higher second liquid reservoir, which second liquid reservoir can be formed, for example, by the apparatus in which the evaporator device is used. For other applications, it may also be preferable to drive the task of the liquid through the use of increased pressure. In particular, by using the feed system, the size of the wetted surface of the insides of the evaporator tubes and the rate of wetting over one can solely capillary effect increased again or a temporally constant wetting of the inner tube surface with liquid in comparison to the wetting be made possible by the resulting in the liquid reservoir vapor bubbles. It is particularly preferred that the feed system can be formed by a tube having openings, for example small holes, spaced apart the evaporator tube walls. In a preferred embodiment of the feed system, the openings are oriented upwards, whereby dirt particles advantageously remain in the feed system and do not pollute the evaporator tubes and in particular do not lead to a blockage of the feed openings.

In a preferred embodiment, the evaporator device comprises a vapor vent for the escape of vaporous liquid. It is preferred for the purposes of the invention that the steam outlet is arranged at a high point of the evaporator device, more preferably at least arranged higher than half the height of the at least two evaporator tubes. It is particularly preferred that the steam outlet is located directly at a highest point of the evaporator device, wherein the vapor-extracted preferentially vaporized liquid can escape through the steam outlet. The evaporator tubes can preferably be connected together by means of a vapor combination with the steam extractor.

In a further preferred embodiment, a cavity for collecting non-condensable gases is arranged above the steam outlet. This is particularly advantageous if the steam extractor is not located at the highest point of the evaporator device, because then a free volume remains available at the top of the evaporator device, in which certain non-condensable gases accumulate, which can disadvantageously disturb other processes if they are unhindered escape through the steam exhaust. It is furthermore preferred that the evaporator device comprises an evaporator inlet for the supply of liquid to be evaporated. Advantageously, with the evaporator inlet, the liquid to be evaporated can be supplied to the evaporator device in such a way that the mixing preferably takes place in the liquid reservoir becomes. This is particularly advantageous, since in this way no liquid can accumulate outside the liquid reservoir and / or outside the at least two evaporator tubes.

In a particularly preferred embodiment of the invention, at least one inlet is arranged geometrically between the at least two evaporator tubes. Preferably, the at least one inlet between the evaporator tubes is arranged with a riser with direct thermal contact to the refrigerator. In other words, it is preferred for the purposes of the invention that the inlet comprises a riser which is in direct thermal contact with a cooling space. For the purposes of the invention, the term "cooling space" preferably describes the space which is to be cooled using the evaporator device. This may be, for example, the room in which the evaporator device is installed. The term "direct thermal contact" can be understood in the context of the invention preferably as an immediate thermal contact. This means according to the invention preferred that no additional items are provided between the inlet and the refrigerator.

It may be particularly preferred that the inlet takes place at the bottom of the riser from a port which is substantially perpendicular to a plane of the evaporator device. Preferably, the inlet pipe is formed by a preferably completely filled riser. This preferably extends over a substantial part of the height of the evaporator tubes and ends above half the height of the evaporator tubes. The upper end of the inlet pipe is preferably connected to at least one evaporator tube. It is preferred that the inlet pipe be in direct thermal contact with the space to be cooled. This is associated with a variety of benefits. On the one hand, standing in the inlet pipe or slowly flowing refrigerant is advantageously available as a cold storage for the space to be cooled. On the other hand, the increased connection with the evaporator tube for the evaporator tube surprisingly forms a kind of feed system, without having to introduce a separate component as a feed system into the evaporator device. Both effects can be enhanced if both the inlet pipe and the connected evaporator pipes from below protrude into the connection with the evaporator tubes and this compound is in particular carried out horizontally. This enables a distribution of the refrigerant via the connected evaporator tubes and an additional elevated refrigerant reservoir is formed, which in turn is available as a cold storage.

Figur 1

eine bevorzugte Ausführungsform der Verdampfervorrichtung (13) mit einem Flüssigkeitsreservoir (1) und zwei Verdampferrohren (2), sowie einer Dampfzusammenführung (3) und einem Dampfabzug (4).

Figur 2

eine bevorzugte Ausführungsform der Verdampfervorrichtung (13), wobei die Innenseite der Verdampferrohre (2) mit der zu verdampfenden Flüssigkeit (7) benetzt ist.

Figur 3

eine bevorzugte Ausführungsform der Verdampfervorrichtung (13) mit Seitenwänden (9) der Verdampferrohre (2), die in das Flüssigkeitsreservoir (1) hineinragen.

Figur 4

eine bevorzugte Ausführungsform der Verdampfervorrichtung (13), bei der sich in der Flüssigkeit (7) im Flüssigkeitsreservoir (1) Dampfblasen (10) bilden.

Figur 5

eine bevorzugte Ausführungsform der Verdampfervorrichtung (13) und die Auswirkung von Dampfblasen (10) bei nicht vollständiger Befüllung.

Figur 6

eine bevorzugte Ausführungsform der Verdampfervorrichtung (13), bei der die Verdampferrohre (2) um einen Winkel α (12) geneigt sind.

Figur 7

eine bevorzugte Ausführungsform der Verdampfervorrichtung (13) mit einem zusätzlichen Aufgabesystem (14)

Figur 8

eine bevorzugte Ausführungsform der Verdampfervorrichtung (13) mit einem Verdampferzulauf (5) in Form eines Steigrohres (15) mit einer Verdampferrohranbindung (17).

Particularly preferred embodiments are shown in the attached figures, without the invention being restricted to these. It shows

FIG. 1

a preferred embodiment of the evaporator device (13) with a liquid reservoir (1) and two evaporator tubes (2), as well as a vapor combination (3) and a steam outlet (4).

FIG. 2

a preferred embodiment of the evaporator device (13), wherein the inside of the evaporator tubes (2) is wetted with the liquid to be evaporated (7).

FIG. 3

a preferred embodiment of the evaporator device (13) with side walls (9) of the evaporator tubes (2), which protrude into the liquid reservoir (1).

FIG. 4

a preferred embodiment of the evaporator device (13), in which form in the liquid (7) in the liquid reservoir (1) vapor bubbles (10).

FIG. 5

a preferred embodiment of the evaporator device (13) and the effect of vapor bubbles (10) in incomplete filling.

FIG. 6

a preferred embodiment of the evaporator device (13), wherein the evaporator tubes (2) are inclined by an angle α (12).

FIG. 7

A preferred embodiment of the evaporator device (13) with an additional feed system (14)

FIG. 8

a preferred embodiment of the evaporator device (13) with an evaporator inlet (5) in the form of a riser (15) with a Verdampferrohranbindung (17).

FIG. 1 shows a preferred embodiment of the evaporator device (13) with a liquid reservoir (1) and two evaporator tubes (2). In particular shows FIG. 1 a capillary structure (6) which is arranged on the inner sides of the preferably two evaporator tubes (2). The evaporator tubes (2) may preferably be referred to as the first and second evaporator tubes. The capillary structure (6) can be formed, for example, by a structured surface or by a capillary material, the structured surface preferably being fixed and / or the capillary material preferably releasably connectable to the evaporator tubes (2). Preferably, the capillary structure (6) comprises materials selected from a group comprising sintered particles and / or chips, preferably metal, glass fiber fabric, structures having narrow flow cavities such as metal sponges, scribed, pressed, soldered and / or welded channels, and / or a combination of it. Accordingly, the capillary structure (6) can be present both as a structured surface on the insides of the evaporator tubes (2), which is then non-detachably connected to the sidewalls, in particular during normal operation of the evaporator device (13), and as capillary material in the interior of the evaporator tubes (FIG. 2), this then, for example, the interior of the evaporator tubes (2) fills or can be pressed by means of a spiral to the side walls of the evaporator tube (2).

Further includes in FIG. 1 illustrated preferred embodiment of the evaporator device (13) has a vapor combination (3) and a steam outlet (4). Above the liquid reservoir (1), an evaporator inlet (5) is arranged, through which the liquid to be evaporated (7) of the evaporator device (13) can be supplied so that the convergence in the liquid reservoir (1) is possible and no liquid (7) outside of the liquid reservoir (1) or outside of the evaporator tubes (2) can accumulate. It is preferred for the purposes of the invention that the steam extractor (4) is arranged at a high, in particular at the highest point of the evaporator device (13) so that the gas to be discharged from the evaporator device (13) can collect at a suitable time to be discharged from the device (13).

It is preferred that the liquid reservoir (1) is completely or substantially completely filled with liquid (7) to be evaporated and that the evaporation takes place from the surface (8) of the liquid (7). It is particularly preferred to provide a particularly large liquid surface (8) within the evaporator device (13) in order to achieve the greatest possible evaporation effect. It is preferred that the liquid reservoir (1) is oriented horizontally or nearly horizontally and is in communication with the evaporator tubes (2), this compound being in particular designed to be liquid and vapor-conducting.

The capillary structure (6), which is preferably located on the inner sides of the evaporator tubes (2), is designed such that capillary effects are produced which lead to migration or transport of the liquid (7) to be evaporated along the inner walls of the evaporator tubes (2 ), whereby the inner sides of the evaporator tubes (2) with a thin film consisting of the liquid (7), in particular the refrigerant wetted. As a result, advantageously a particularly large evaporation surface (8) of the liquid to be evaporated (7) is formed, which promotes effective evaporation of the liquid (7). It is particularly preferred if the evaporator tubes (2) comprise copper and / or brass. But there are also evaporator tubes (2) comprising aluminum or made of aluminum, conceivable. It is particularly preferred for the purposes of the invention, when the evaporator tubes (2) are wetted as high as possible with the liquid to be evaporated (7), thus forming a particularly large evaporation surface (8) and the evaporation of the liquid (7) is improved.

FIG. 2 shows a preferred embodiment of the evaporator device (13), wherein the inner sides of the evaporator tubes (2) are wetted with the liquid to be evaporated. In particular shows FIG. 2 a liquid reservoir (1) which is completely filled with the liquid (7) to be evaporated. The liquid (7) is according to FIG. 2 so high in the evaporator device (13) that the liquid (7) also extends into the lower regions of the evaporator tubes (2). The so characterized evaporator tubes (2) are preferably referred to as "partially flooded evaporator tubes" within the meaning of the invention. Due to the capillary effects of the Capillary structure (6) is caused in the evaporator tubes (2), the liquid (7) on the side walls of the evaporator tubes (2) is pulled up, in particular, forms a thin liquid film, which preferably according to the invention, an evaporation or liquid surface (8) The enlargement of this surface (8) is an object of the present invention in order to achieve the greatest possible evaporation effect with respect to the liquid (7) to be evaporated in the liquid reservoir (1).

At the in FIG. 3 In the embodiment shown, the side walls (9) of the evaporator tubes (2) protrude into the liquid reservoir (1) or the liquid (7) contained therein. This advantageously wets the capillary structure (6) provided on the side walls (9) of the evaporator tubes (2) with the liquid (7) to be evaporated. Furthermore, capillary material, which is located, for example, in the interior of the evaporator tubes (2), can come into contact with the liquid (7) in the liquid reservoir (1). This advantageously makes it possible for the liquid (7) to be sucked into the capillary material by the capillary effects and forces, whereby the surface (8) of the liquid (7) to be evaporated advantageously increases considerably, so that a particularly effective evaporation of the liquid (7) is reached, even if the reservoir (1) is not completely filled with the liquid (7).

FIG. 4 shows a preferred embodiment of the evaporator device (13), in which form in the liquid (7) in the liquid reservoir (1) vapor bubbles (10). In FIG. 4 These vapor bubbles (10) are shown, which may arise in the liquid reservoir (1) or in the partially flooded evaporator tubes (2). Especially with small inner diameters of the evaporator tubes (2), these vapor bubbles (10) can not flow freely through the evaporator tubes (2). When the liquid reservoir (1) is completely or substantially completely filled with liquid (7) to be evaporated, liquid (7) is preferably blown into the evaporator tubes (2), whereby an elevated fill level (11) in the evaporator tubes (preferably) is temporarily suspended ( 2). Due to the preferred inner diameter of the evaporator tubes (2), the vapor bubbles (10) in the evaporator tubes (2) rise until they burst or slowly past the liquid to be evaporated (7), whereby the evaporator tubes (2) preferably cyclically from the inside with Liquid (7) are wetted. As a result, the desired, flat-shaped thin liquid film on the inside of the evaporator tubes (2) or on the capillary structure (6) can form very quickly.

FIG. 5 shows a preferred embodiment of the evaporator device (13) and the effect of vapor bubbles (10) in incomplete filling of the liquid reservoir (1). In FIG. 5 In particular, the evaporator device (13) is placed in an environment to be cooled, wherein a thermal contact between the outer walls of the liquid reservoir (1) and the environment to be cooled is formed. In this preferred embodiment of the invention, the vapor bubbles (10) are formed in particular also in the vicinity of the bottom of the liquid reservoir (1), wherein the vapor bubbles (10) in this preferred embodiment of the invention in the evaporator tubes (2). As a result of the particularly deep formation of the vapor bubbles (10) within the liquid (7) in the liquid reservoir (1) close to the bottom of the liquid reservoir (1), the vapor bubbles (10) enter the evaporator tubes (2) at high speed Within the tubes (2) can rise particularly high and thus the wetting of the inner sides of the evaporator tubes (2) can advantageously further improve.

This effect is particularly enhanced when the evaporator tubes (2) have a particularly small inner diameter, particularly preferably less than 13 mm. Evaporator tubes (2) with such a small diameter also have the advantage that the capillary material, which is not firmly connected to the side walls of the evaporator tubes (2), can be held in the evaporator tubes (2) without additional stiffening or fastening structures. because it is pressed due to its voluminous structure against the side walls of the evaporator tubes (2).

FIG. 6 shows a preferred embodiment of the evaporator device (13), wherein the evaporator tubes (2) with an upper end of the liquid reservoir (1) form an angle α (12). In particular shows FIG. 6 an evaporator device (13) with inclined evaporator tubes (2), wherein the inclination takes place with the inclination angle α (12). The inclination angle (12) is between the side walls of the evaporator tubes (2) and an imaginary upper termination plane of Liquid reservoir (1) formed. Also in this preferred embodiment of the evaporator device (13) form inside the liquid (7) in the liquid reservoir (1) vapor bubbles (10), which rise in the evaporator tubes (2) and for wetting the capillary structure (6) on the side walls or in the interior contribute to the evaporator tubes (2).

FIG. 7 shows a preferred embodiment of the evaporator device (13) with an additional delivery system (14), with the liquid (7), which has reached an upper portion of the evaporator device (13), can be returned to the evaporator tubes (2) without that In addition, energy must be expended. It is particularly preferred that the feed system is formed by a tube having openings, for example small holes, spaced apart the evaporator tube walls. The provision of the delivery system (14) advantageously makes it possible to recycle refrigerant, which has collected in the region of the delivery system (14) of the evaporator device (13), into the evaporator tubes (2). This is preferably done by the use of gravity or by pressure application. The utilization of gravity is particularly advantageous if the application system (14) in an upper region of the evaporator device (13), and thus preferably above the evaporator tubes (2), is arranged, so that the refrigerant, for example, through the openings in the tube, which preferably forms the feed system (14), flow through and thus can reach into the region of the evaporator tubes (2). It has been found that the use of a feed system (14) can further greatly improve the wetting of the capillary structure (6) in the evaporator tubes (2), in particular the rate at which the capillary structure (6) is wetted compared to one alone capillary wetting increased.

FIG. 8 shows a preferred embodiment of the evaporator device (13), in which the evaporator inlet (5) is guided from behind into the evaporator device (13) and the liquid to be evaporated (7) via a riser (15) and an evaporator pipe connection (17) is supplied. As a result, the liquid to be evaporated (7) flows via the evaporator tubes (2) into the primary liquid reservoir (1). By way of the riser pipe and evaporator pipes (16) projecting into the evaporator pipe connection (17), an increased liquid reservoir (18) with the liquid surface (8) is advantageously formed.

LIST OF REFERENCE NUMBERS

1

liquid reservoir

2

vertical tube / evaporator tube

3

Steam merging

4

steam vent

5

evaporator feed

6

capillary

7

liquid to be evaporated

8th

Liquid surface / evaporation surface

9

Side walls of the evaporator tubes, which protrude into the liquid reservoir

10

vapor bubbles

11

(increased) level

12

Angle α

13

evaporator device

14

Injection system

15

Riser of the evaporator inlet

16

Side walls of the riser of the evaporator inlet, which protrude into the evaporator tube connection

17

Evaporator tube connection

18

increased fluid reservoir

Claims (15)

Evaporator device (13) comprising at least one liquid reservoir (1) and at least two substantially parallel-connected evaporator tubes (2)
characterized in that
the evaporator tubes (2) have a capillary structure (6) and the liquid reservoir (1) is arranged below the evaporator tubes (2) and communicates with the evaporator tubes (2) in liquid and / or vapor-conducting fashion. Evaporator device (13) according to claim 1
characterized in that
the evaporator device (13) comprises a steam passage for the passage of a vapor flow inside the evaporator tubes (2). Evaporator device (13) according to claim 1 and / or claim 2
characterized in that
the liquid reservoir (1) can be completely or substantially completely filled with a liquid (7), wherein the liquid (7) is a refrigerant, preferably water, ethanol or ammonia. Evaporator device (13) according to one or more of the preceding claims
characterized in that
at least one of the evaporator tubes (2) projects into the liquid reservoir (1). Evaporator device (13) according to one or more of the preceding claims
characterized in that
the evaporator tubes (2) are arranged substantially perpendicular to the liquid reservoir (1) or
in that the evaporator tubes (2) form an angle α (12) with the liquid reservoir (1), the angle α (12) being in the range of 30 to 90 ° is, more preferably at 45 ° or 90 °. Evaporator device (13) according to one or more of the preceding claims
characterized in that
the capillary structure (6) is formed by a structured surface and / or a capillary material, the capillary structure (6) comprising materials selected from a group comprising sintered particles and / or chips, preferably metal, glass fiber fabric, structures having narrow flow cavities such as metal sponges, incised, pressed on, soldered and / or welded on channels and / or a combination thereof. Evaporator device (13) according to claim 6
characterized in that
the structured surface is firmly connected to the evaporator tubes (2) or Evaporator device (13) according to claim 6
characterized in that
the capillary material is releasably connectable to the evaporator tubes (2). Evaporator device (13) according to one or more of the preceding claims
characterized in that
a direct spatial contact between the liquid reservoir (1) and an environment of the evaporator device (13), said spatial contact is a thermal contact between the liquid (7) in the liquid reservoir (1) and the environment. Evaporator device (13) according to one or more of the preceding claims
characterized in that
the evaporator tubes (2) comprise a square channel, wherein the angular Channel plates having a distance of a maximum of 5 to 15 mm, preferably 8 to 12 mm, more preferably 10 mm at a minimum distance. Evaporator device (13) according to one or more of the preceding claims
characterized in that
the evaporator device (13) comprises a feed system (14) with outlet openings for delivering refrigerant to the at least one evaporator tube (2), wherein the feed system (14) is arranged above the evaporator tubes (2). Evaporator device (13) according to one or more of the preceding claims
characterized in that
the evaporator tubes (2) comprises brass and / or copper. Evaporator device (13) according to one or more of the preceding claims
characterized in that
above the steam exhaust (4) a cavity for collecting non-condensable gases is arranged. Evaporator device (13) according to one or more of the preceding claims
characterized in that
the evaporator device (13) comprises a steam outlet (4) for the escape of vaporous liquid and / or an evaporator inlet (5) for the supply of liquid (7) to be evaporated. Evaporator device (13) according to one or more of the preceding claims
characterized in that
at least one inlet is arranged between the evaporator tubes, wherein the inlet comprises a riser, which is in direct thermal contact with a cooling space.

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