Falling film evaporator

Abstract

The invention discloses a heat exchanger (1, 100) of a horizontal tube falling film evaporator type. The heat exchanger (1, 100) comprises a shell (10, 110); at least one tube bundle (20, 120, 140) of heat exchanger tubes (21, 121, 141) arranged inside the housing (10, 110), the tube length (Lt) of the heat exchanger tubes (21, 121, 141) defining a horizontal x-direction and the vertical extension length (Htb, Htb1, Htb2) of the heat exchanger tubes (21, 121, 141) of the tube bundle (20, 120, 140) defining a z-direction orthogonal to the x-direction; and at least one refrigerant distribution layer (30, 130, 150) located above the heat exchanger tubes (21, 121, 141) of the at least one tube bundle (20, 120, 140), the at least one refrigerant distribution layer (30, 130, 150) comprising perforated tubes (31, 131, 151) having a plurality of holes (133a. 1, 133a. 2, 133a. 3, 133a. 4, 133a. 5, 133a. 6, 133a. 7) for discharging refrigerant to the heat exchanger tubes (21, 121, 141) of the tube bundle (20, 120, 140) over which the refrigerant distribution layer (30, 130, 150) is located, where the longitudinal axis of at least some of the perforated tubes (31, 131, 151) is substantially parallel to the longitudinal axis of the perforated tubes (31, 131, 151). A horizontal y direction orthogonal to the x direction defined by the heat exchanger tubes (21, 121, 141) is defined, and wherein the perforations on the perforated tubes (31, 131, 151) have a longitudinal y direction orthogonal to the x direction defined by the heat exchanger tubes (21, 121, 141) and consist of a plurality of holes (133a. 1, 133a. 2, 133a. 3, 133a. 4, 133a. 5, 133a. 6, 133a. 7) arranged in groups of holes (133a, 133b, 133c, 133d) wherein each group of hole groups (133a, 133b, 133c, 133d) is arranged on a circumference lying on a vertical xz plane passing through the heat exchanger tubes (21, 121, 141) of the tube bundle (20, 120, 140), the tube bundle (20, 120, 140) of the heat exchanger tubes (21, 121, 141) is provided with a plurality of tubes (121a. 1, 121a. 2, 121b. 1, 121b. 2, 141a. 1, 141a. 2, 141b. 1, 141b. 2) and is located above the respective heat exchanger 30 tubes (121a. 1, 121a. 2, 121b. 1, 121b. 2, 141a. 1, 141b. 2) of the tube bundle (20, 120, 140) of the heat exchanger tubes (21, 121, 141).

Description

Background Art

[0001] Conventional vapor compression refrigerant systems used for air conditioning or refrigeration include an evaporator, which is a heat exchanger where thermal energy is transferred between the process fluid that must be cooled and the system's refrigerant fluid.

[0002] Different types of evaporators have been designed. Three types offer the highest performance: flooded evaporators, pure falling film evaporators, and mixed falling film evaporators. Of these, the first and last types have achieved the greatest success in air conditioning and refrigeration applications.

[0003] All three types are characterized by multiple horizontal tubes within a shell. The process fluid to be cooled flows within the tubes and transfers heat to the refrigerant fluid that flows within the shell side of the heat exchanger and contacts the outer surface of the tubes.

[0004] Since these types of evaporators all belong to the same subcategory of the shell and tube heat exchanger family, the passage of the process fluid inside the tubes can be carried out through different structures, called single-pass (1P) or multi-pass (2P double-pass, 3P triple-pass, 4P, ....), and the design chosen depends on the available temperature difference and the volume flow rate of the fluid, so as to work with the optimal velocity inside the tubes to achieve heat exchange performance without exceeding the limit of the permissible pressure drop, the latter being proportional to the pumping power required to convey the process fluid.

[0005] In a once-through configuration, the process fluid enters the pipe on one side and exits on the other.

[0006] In a two-pass configuration, the process fluid enters only a small area on one side of the main pipeline, exits on the other side, forming the first channel, and then travels in the opposite direction of the first pass to re-enter the remaining main pipeline section.

[0007] In a structure with a greater number of channels, the fluid flows alternately in opposite directions through a number of sections of the total tube bundle equal to the number of channels.

[0008] In a flooded evaporator, the tubes are located inside the shell, roughly corresponding to the lower half of the shell. During operation, refrigerant, in the form of a liquid or a liquid-gas mixture, enters the heat exchanger through an inlet connection, typically located at the bottom of the shell. It fills the portion of the shell containing the tubes (i.e., the lower half), thereby wetting the outer surfaces of the tubes and achieving the desired high performance. Obviously, one disadvantage of this design is the high refrigerant charge required to fully wet the tube bundle.

[0009] The difference between a pure falling film evaporator and a flooded evaporator is that the refrigerant is distributed on the outer surface of the tubes in the form of liquid or liquid-gas mixture through a distribution system usually located above the tube bundle. The liquid part of the refrigerant distributed on the upper tube rows of the bundle will start to partially evaporate, the remaining part will fall on the lower tube rows and form a liquid film on the lower tube rows. The liquid film will thin as it descends the tube rows to the bottom due to the continuous evaporation process.

[0010] Since the optimal distribution of the refrigerant on the outer surface of the tubes of the bundle is complex, in order to continue to obtain good heat transfer performance similar to that of a flooded evaporator, the refrigerant must be delivered in such a way that the excess part after the evaporation process must be discharged from the lower part of the shell below the tube bundle, since in a pure falling film evaporator one does not want the refrigerant to overflow from any part of the tube bundle. Usually, this excess liquid refrigerant is recirculated through a liquid recirculation system, which complicates the system structure.

[0011] The hybrid falling film evaporator type is basically similar to the pure falling film evaporator, the difference being that instead of recirculating the excess liquid, it is allowed to accumulate at the bottom of the shell until it fills a certain part of the tube bundle, which actually operates as a flooded evaporator: hence the name hybrid.

[0012] Compared to the solution with a flooded evaporator, the hybrid structure has the advantage of reducing the refrigerant charge of the pure falling film type, which remains almost constant, while simplifying the configuration by eliminating the liquid recirculation system.

[0013] All three types can be easily implemented in a multi-circuit structure, which can be used in very common applications that require high cooling capacity, where it is necessary to use several compressors, each belonging to an independent cooling circuit: this structure is also usually required for redundancy reasons.

[0014] In this multi-circuit evaporator structure, the process fluid to be cooled is in contact with different parts of the heat exchange surface, each part being in contact with the refrigerant fluid belonging to a different refrigerant circuit. This structure is achieved by using intermediate tube sheets that separate the different circuits on the refrigerant side: in each single pass of the process fluid in any tube, the process fluid exchanges heat with different circuits.

[0015] In general, one of the key objectives of a heat exchanger is to maximize the heat transfer performance of the heat exchanger surface.

[0016] For horizontal tube falling film evaporator heat exchangers, whether they are hybrid or pure falling film, whether they are used for air conditioning or refrigeration applications, and whether the fluid to be distributed is a liquid refrigerant or a two-phase gas-liquid refrigerant, in order to maximize the heat transfer performance of the heat exchanger surface, some of the main goals that need to be achieved are the optimal distribution of the refrigerant on the outer surface of the tubes, including the mass flow rate and vapor quality per unit length of each specific tube (which in turn depends on the required cooling capacity, which is determined by the specific conditions, temperature and flow rate of the heat transfer fluid / process fluid flowing in the tubes), and the resulting optimal geometry of the liquid refrigerant film vaporizing around the tubes. The optimal distribution of the refrigerant on the outer surface of the tubes is severely constrained by several factors, as follows:

[0017] Due to cost reasons, a compact tube bundle and shell assembly structure is required;

[0018] For cost reasons, the need to reduce the number and complexity of components required;

[0019] Due to the pressure drop, the refrigerant evaporates along the distribution lines (this means that the refrigerant fluid can be distributed at different points with different vapor qualities);

[0020] The interaction between the refrigerant (single-phase or two-phase) distributed on the outer surface of the tube and the vaporized refrigerant flow generated on the outer surface of the tube (through heat exchange with the fluid to be cooled flowing in the tube) occurs inside the shell and outside the tube. This interaction leads to the destruction of the liquid falling film and has a negative impact on the heat transfer coefficient;

[0021] "Static" dispatch systems have difficulty meeting optimization goals under very different load conditions, such as full load and minimum load simultaneously; and / or

[0022] Distribution system design is difficult to meet optimization goals under very different application conditions, such as the evaporator of a water chiller for medium- and high-pressure refrigerants (where the difference between condensing and evaporating pressures is large) and low-pressure refrigerants.

[0023] One thing that all known designs have in common is that one of the main reasons for not achieving this optimal distribution is the inefficiency of the refrigerant fluid distribution on the outer surfaces of the horizontal tubes in the upper tube bank (the bank immediately below the distribution system) after leaving the universal distribution system. Due to the limited number of components and the limited space required, the design solutions often reduce the efficiency of the first distribution in the upper tube bank.

[0024] These distribution inefficiencies on the upper tube banks can only be partially recovered as the liquid film subsequently descends and is distributed to the lower tube banks, so it plays a key role in the design of any distribution system.

[0025] In the prior art, two types of refrigerant distribution systems are known: pure liquid distributors and vapor / liquid mixture distributors.

[0026] Pure liquid distributor-type refrigerant distribution systems require a vapor separation system upstream of the distribution system, which increases complexity. Typically, pure liquid distributor systems are designed as a set of parallel pipes interconnected by a manifold (also called a header). The lower portion of the parallel pipes is provided with holes of various geometric shapes (circular, oval, rectangular, etc.), allowing the liquid to fall directly onto the heat exchanger tubes along a roughly vertical trajectory (or at a slight angle to the vertical).

[0027] Typically, the distributor pipes are parallel to the heat exchanger pipes, which can reduce the necessary number of pipes for the distributor and the relative welding to the manifold.

[0028] To be efficient, these systems require a large number of holes because in the first upper row of heat exchanger tubes, the transported liquid remains localized relative to the vertical direction through the holes and slowly begins to redistribute along the length of the tubes.

[0029] For this purpose, perforated plates (or thin sheets) are often used to redistribute the liquid, but this in any case hinders the passage of the rising steam that is being generated. The damage is greatest at part load, where the flow rate is very low and the liquid tends to stay in a more localized area, thereby exacerbating the formation of dry spots on the heat exchanger tubes.

[0030] Refrigerant distribution systems of the vapor / liquid mixing distributor type generally do not use perforated tubes, but rather use nozzles designed in an optimized manner to utilize the high output velocity of the refrigerant in the two-phase state to obtain a spray effect capable of distributing the refrigerant over a large surface.

[0031] However, these systems using nozzles have some limitations:

[0032] Firstly, in order to effectively utilize the spray effect and obtain good distribution over a large area, free space is required between the nozzle and the tube bundle. Therefore, the vertical dimension of the distribution system, including the nozzle and the free space between the nozzle itself and the tube bundle, usually has a non-negligible extension. This solution is not the best choice in cases where the overall cost of the evaporator is particularly sensitive to compactness.

[0033] Furthermore, allocation efficiency can vary significantly when capacity loads change.

[0034] In addition, compared to a pure liquid distribution system, a vapor / liquid hybrid distribution system (whether using a perforated tube or a nozzle) is prone to intermittent and stratified flow phenomena inside the manifold and the pipe itself at very low refrigerant flow rates. This intermittent flow phenomenon often results in uneven distribution. One way to avoid such problems is to carefully design the dimensions of the different components and take into account the entire operating range.

[0035] Another problem that often arises when applying a horizontal tube shell and tube falling film evaporator, whether pure falling film or hybrid falling film, is that a large amount of liquid in the form of droplets and mist is entrained in the refrigerant vapor outlet stream produced and sent to the compressor. The presence of refrigerant liquid at the compressor inlet can pose a risk to the reliability of the compressor and can cause overall management of the water chiller to fail.

[0036] Embodiments of various types of falling film evaporators are disclosed, for example, in a) US 6,830,099 B2, b) US 9,759,461 B2, c) US 10,132,537 B1 and d) EP 2 482 007 B1.

[0037] All of the above evaporator designs have problems to varying degrees.

[0038] All structures from a) to c) have a single layer distribution system: since the tube bundle can have multiple rows of horizontal tubes in most cases, usually more than 4 rows, the single layer distribution system has the problem of large differences in the thickness of the falling liquid film

[0039] According to experimental evidence, the optimization range of the heat transfer coefficient thus derived is not very wide. It is necessary to ensure that the liquid film in the horizontal tube row located at the lowest position of the distribution system has sufficient thickness (or at least surface wettability), which determines that it is necessary to overfeed the first few rows of tubes. The more tube rows that need to be fed, the less ideal the distribution of refrigerant on the horizontal top tube row.

[0040] All structures from a) to c) have a counter-flow flow structure, i.e. the falling liquid flows in the opposite direction to the refrigerant vapor produced at the lower part of the evaporator: this structure, if it cannot limit the speed of the rising vapor by appropriately increasing its free passage section in different ways, will have two negative effects:

[0041] 1) the liquid film on the tube breaks, thus negatively affecting the heat transfer coefficient;

[0042] 2) the liquid droplets entrained in the vapor flow, if not sufficiently separated and recovered or evaporated using a heat source, will eventually enter the suction inlet of the compressor, negatively affecting the compressor and the water chiller.

[0043] The illustrated configuration solves this problem by creating a free passage for the rising vapor, but this results in a reduction in the number of heat exchange tubes available for a given shell size and has a significant negative impact on the product cost per unit of capacity. This again emphasizes the importance of refrigerant distribution in the uppermost rows to at least mitigate these problems.

[0044] Configuration d) solves the problem of liquid entrainment by adopting a co-current arrangement of vapor and liquid flows: Because the portion of the tube bundle dedicated to falling-film evaporation is shrouded, the generated vapor is forced to flow downwards with the distributed liquid, then suddenly changes direction and rises laterally again (between the shroud and the shell) to the vapor outlet connection, which is always located in the upper part of the shell. Configuration d) also introduces at least one additional distribution layer, thus reducing the problems caused by overfeeding.

[0045] With this configuration (d), the free path for the rising vapor is reduced but not eliminated, thus still negatively impacting the potential maximum filling of the shell and tube. The overall path of the vapor from the generating surface to the suction port is lengthened and its direction changes, increasing the overall refrigerant pressure drop and impacting overall performance.

[0046] The problem to be solved by the present invention is therefore to provide a heat exchanger of the horizontal tube falling film evaporator type which allows an optimized distribution of the refrigerant on the upper row of heat exchanger tubes of the tube bundle. Summary of the Invention

[0047] This problem is solved by a heat exchanger of the horizontal tube falling film evaporator type having the features of independent claim 1. Further advantageous features of the heat exchanger are subject matter of the dependent claims.

[0048] According to the present invention, a heat exchanger (1, 100) of the horizontal tube falling film evaporator type comprises a shell and heat exchanger tubes of at least one tube bundle arranged in the shell.

[0049] It should be emphasized that the horizontal tube falling film evaporator according to the present invention can be a mixed type evaporator or a pure falling film type evaporator; the present invention is not limited to one of these types.

[0050] The heat exchanger tube has a tube length L defining a horizontal x direction t , meaning that the tubes are essentially straight. Furthermore, because the heat exchanger is a falling-film type, this tube length necessarily defines a horizontal axis, thereby defining the heat exchanger's orientation in space. It is important to note that because the claimed heat exchanger is a falling-film type with horizontal tubes, the heat exchanger's orientation in space is clearly defined, and those skilled in the art can clearly define the "upward" and "downward" directions of a given heat exchanger by the direction of refrigerant descent.

[0051] It should also be noted that the term "tube bundle" is used to describe a group of multiple horizontally extending rows of heat exchanger tubes, where all tubes in a row are located on the same horizontal plane (i.e., at least one heat exchanger tube is positioned vertically differently from the others; typically, multiple rows of heat exchanger tubes form a tube bundle). The term "tube bundle" does not imply that the group of heat exchanger tubes is held together by some device.

[0052] Therefore, the heat exchanger tube bundle has a vertical extension length H tb 、H tb1 、H tb2 (ie a certain amount of space is required in the vertical direction), which defines the z direction orthogonal to the x direction. Preferably, the tube length L t Greater than the vertical extension length H tb .

[0053] The heat exchanger according to the present invention further comprises at least one refrigerant distribution layer located above at least one bundle of heat exchanger tubes. This condition is satisfied as long as a bundle of heat exchanger tubes is arranged below the refrigerant distribution layer, which enables the refrigerant distribution layer to also be located between two bundles of heat exchanger tubes.

[0054] The at least one refrigerant distribution layer includes perforated tubes having holes formed therein for discharging refrigerant toward a heat exchange tube bundle located above the refrigerant distribution layer. In the present invention, "discharging toward the tube bundle" means that the refrigerant discharged from these holes (these holes may also be, for example, part of a nozzle inlet; the present invention is not limited to purely liquid refrigerant systems) initially moves in a direction having a vertical component toward the tube bundle. In other words, "discharging toward the tube bundle" does not necessarily mean that the refrigerant is discharged vertically or directly toward the tube bundle.

[0055] A key feature of the present invention is that at least some of the perforated tubes have longitudinal axes defining a horizontal y-direction orthogonal to the x-direction defined by the heat exchanger tubes. Due to this geometry, perforated tubes extending along this direction extend across multiple heat exchanger tubes belonging to the tube bundle and may constitute at least a portion of a layer of heat exchanger tubes within the tube bundle. Conversely, different sections of the same heat exchanger tube within the top layer of the tube bundle are typically supplied with refrigerant by different perforated tubes arranged along this direction.

[0056] Another important feature of the present invention is that the perforations of the perforated tubes are formed by groups of holes arranged such that the longitudinal y-direction of the perforated tubes is orthogonal to the x-direction defined by the heat exchanger tubes, with each group of holes being arranged circumferentially along a vertical xz plane passing through a heat exchanger tube in the tube bundle. Furthermore, the holes in a given group of holes are positioned above a corresponding heat exchanger tube in the heat exchanger tube bundle, such that refrigerant flowing from the holes in the given group of holes is directed toward the heat exchanger tube.

[0057] As already mentioned above, the holes may also form part of the nozzle.

[0058] In particular, it should be noted that the refrigerant distribution layer does not need to be located entirely within the shell in order to achieve the claimed features. However, this is clearly a necessary condition for the perforated tube sections having hole groups, for example, a common supply line for the perforated tubes or individual supply lines for the perforated tubes may also be located outside the shell.

[0059] The perforated tube preferably has a thickness capable of withstanding an internal pressure between 10 kPa and 600 kPa. Preferred thicknesses range from 0.5 mm to 4 mm, depending on the application and material. Preferred materials are copper, carbon steel, and stainless steel.

[0060] The proposed structure is an improvement compared to the prior art since it exploits the kinetic energy of the fluid jet emerging from the orifice and the angle of impact of the jet itself with the outer surface of the heat exchanger tube to be fed, in order to obtain a better distribution of the jet itself along the longitudinal axis of the heat exchanger tube.

[0061] It is important to note that this configuration not only includes variations in the number, size, and / or shape of multiple holes between different perforated tube groups, but also in the number, size, and / or shape of multiple holes within a given perforated tube group, and even within the same group. This allows those skilled in the art to optimize refrigerant distribution for the optimal velocities of different refrigerant flows and across the entire operating range of the evaporator. This advantage is most significant under conditions of minimal load and low fluid volume distribution.

[0062] The preferred diameter of the holes is between 0.3 mm and 1 mm.

[0063] Preferably, the number of the plurality of holes in each hole group is between 5 and 11 to help reduce the number of perforated tubes required to cover the entire heat exchanger tube length.

[0064] It is also preferred that the number of multiple holes in each hole group is odd, and the position of each hole group is symmetrical relative to the central hole located at the bottom of the perforated tube, which directly faces the heat exchanger tube located below the hole group (and therefore discharges refrigerant in a substantially vertical direction).

[0065] A more even distribution of refrigerant across the heat exchanger tubes can be achieved if the holes in a given hole group are arranged around the tube circumference so that the distances between a first intersection point formed by a corresponding first line passing through a first hole and the center of the perforated tube and the heat exchanger tube located below the hole group and a second intersection point formed by a corresponding second line passing through an adjacent second hole and the center of the perforated tube and located below the hole group are equal. This way, assuming that the refrigerant discharged from the holes propagates linearly, the refrigerant will impinge on the heat exchanger tubes at equidistant locations.

[0066] Preferably, the condition 1<(A / D pp ) / n h <3, where A defines the distance between the centers of two adjacent perforated tubes having a longitudinal axis defining a horizontal y direction orthogonal to the x direction defined by the heat exchanger tubes, where D pp is the diameter of the perforated tube, n h is the number of holes that belong to a hole group.

[0067] The preferred configuration of the refrigerant distribution layer includes a central refrigerant feed tube extending parallel to the heat exchanger tubes and a plurality of perforated tubes, the longitudinal axes of which define a horizontal y-direction orthogonal to the x-direction defined by the heat exchanger tubes. The perforations in the perforated tubes are formed by groups of holes, with the holes in each group arranged circumferentially along a vertical xz plane passing through a heat exchanger tube in the bundle, the plane being located above a heat exchanger tube in the bundle. The perforated tubes are directly connected to the central feed tube. Typically, this results in an antenna-like structure.

[0068] According to a preferred embodiment of the heat exchanger, particularly suitable for use in situations where a process fluid to be cooled flows within a single-pass heat exchanger tube, the diameter and / or number of holes in each perforated tube group is greater than the diameter and / or number of holes in each perforated tube group. The longitudinal axis of the first perforated tube defines a horizontal y-direction orthogonal to the x-direction defined by the heat exchanger tube, the x-direction being located near the high-temperature end of the heat exchanger tube and corresponding to the high-temperature region of the process fluid to be cooled flowing within the heat exchanger tube. The longitudinal axis of the second perforated tube defines a horizontal y-direction orthogonal to the x-direction defined by the heat exchanger tube and located away from the high-temperature end of the heat exchanger tube. However, the higher the heat exchange capacity, the more refrigerant can evaporate, and the greater the ΔT, or temperature difference between the refrigerant being cooled and the medium within the heat exchange tube, the more refrigerant mass flow can be distributed to the high-temperature side rather than the low-temperature side.

[0069] Another way to achieve this effect that may be used alternatively or additionally is to have the distance between adjacent perforated tubes having longitudinal axes defining a horizontal y-direction orthogonal to the x-direction defined by the heat exchanger tubes near the high temperature end of the heat exchanger tubes be less than the distance between adjacent perforated tubes having longitudinal axes defining a horizontal y-direction orthogonal to the x-direction defined by the heat exchanger tubes far from the high temperature end of the heat exchanger tubes.

[0070] Preferably, the heat exchanger comprises a plurality of refrigerant distribution layers.

[0071] The refrigerant distribution layers can be arranged horizontally adjacent to one another, in particular in such a way that at least two refrigerant distribution layers arranged horizontally adjacent to one another are arranged over different sections of the same bundle of heat exchanger tubes.

[0072] Additionally or alternatively, the heat exchanger may include a plurality of refrigerant distribution layers arranged vertically up and down in a vertical z-direction and away from each other, and a plurality of heat exchanger tube bundles arranged vertically in the vertical z-direction and away from each other, the plurality of refrigerant distribution layers and the plurality of heat exchanger tube bundles being arranged in such a manner that each refrigerant distribution layer is arranged above at least one heat exchanger tube bundle, thereby forming a distribution layer.

[0073] Each refrigerant distribution layer has the characteristics of the refrigerant distribution layer described above, but these characteristics are not necessarily identical in terms of collector, tube diameter, hole diameter, hole grouping, number of holes, and the angle between holes / refrigerant discharge angle from the holes. Each distribution layer, thus defined, is arranged at a different height (level) within the shell to distribute refrigerant to a specific portion of the tube bundle located below the distribution layer in falling film mode. The proportion of refrigerant flow distributed by each distribution layer will depend on the geometric characteristics of the components designed for each refrigerant distribution layer.

[0074] In this way, each distribution layer can be designed so that the amount of refrigerant in each distribution layer is likely to be equal to the amount of refrigerant expected to evaporate in the section of the tube bundle below it, depending on the type of tubes and the conditions of the fluid at each pass in that particular section of tubes (tube inlet temperature and fluid velocity).

[0075] To illustrate the above, an example is given. In a shell and tube structure with a double water channel on the tube side, the temperature in the lower part of the first channel is higher and the temperature in the upper part of the second channel is lower. It is expected that the evaporation flow rate of the liquid refrigerant evenly distributed on the heat exchanger tubes will be higher in the tubes of the first channel than in the tubes of the second channel, and the temperature will be higher: due to the uniform distribution on all tubes, the liquid film distributed in the upper part will be excessive and will not be completely evaporated, but will fall into the lower part and partially compensate for the shortage of liquid refrigerant distributed in the lower part of the tube, and the liquid refrigerant in the lower part will be completely evaporated.

[0076] This compensation phenomenon will not be complete, since the overdistribution of the upper liquid, also due to the maximum flow rate of the steam, will also cause a non-negligible interaction between liquid and steam, leading to the rupture of the liquid film and the entrainment of liquid in the steam flow to the suction connection of the compressor.

[0077] In summary, the best practice is to distribute more refrigerant in the lower part of the tube bundle than in the upper part, which corresponds to the first passage of the fluid in the tube, and this can be achieved in the above manner.

[0078] This advantage is realized in refrigeration cycle applications where the flow of refrigerant fluid from a throttling / laminating device, typically an expansion valve, is distributed among a plurality of distribution layers.

[0079] In order to further improve this distribution, each distribution layer may comprise means for regulating the flow of refrigerant to the distribution layer, such as a valve.

[0080] Preferably, the degree of opening of the device for regulating the flow of refrigerant to the distribution layer is regulated by a control system. Typical parameters used as control set points include, but are not limited to:

[0081] Compressor inlet overheating,

[0082] The compressor outlet is overheated,

[0083] Compressor power input,

[0084] Compressor capacity regulation, or

[0085] The pressure in the distribution layer drops.

[0086] In another preferred embodiment of the present invention, the vertical distance between adjacent rows of heat exchanger tubes forming the heat exchanger tube bundle increases gradually from bottom to top. This structure limits the velocity of rising steam, which tends to increase with increasing height due to increasing total steam flow. The velocity of the rising steam interacts with the liquid film on the outer surface of the tubes. This interaction can disrupt the falling film and negatively impact the heat transfer coefficient.

[0087] The optimal increment of the distance between tubes in different row pairs (from bottom to top) can follow a linear law for a subset of tubes in each row fed by the same heat transfer fluid channel (the process fluid has the same inlet temperature for all these tubes).

[0088] In another preferred embodiment, the shell has a rectangular or square cross-section in the yz plane. This makes it easier to operate in pure falling film mode (rather than mixed falling film mode) while still maintaining high overall heat transfer performance and minimizing the total refrigerant charge, because the number of heat exchange tubes in each row and the bottom of the shell can be equal; in contrast, in a standard circular shell cross-section, the number of heat exchange tubes between adjacent rows varies greatly.

[0089] The significant difference in the number of tubes per row in a standard circular shell cross-section makes optimal distribution difficult, necessitating overfeeding of refrigerant to maintain performance. Without a hybrid configuration, a recirculation system must be used to manage overfeeding. This solution is best suited for low-pressure refrigerants such as R1233zd and R1234ze, as this shape has poor pressure resistance.

[0090] Furthermore, it is advantageous to install an active demister or integrated heat exchanger above the topmost refrigerant distribution layer. This ensures that the refrigerant is completely evaporated before entering the compressor, even under extreme operating conditions. The heat medium flowing through the pipes of this active demister or integrated heat exchanger can be liquid refrigerant from the condenser or an additional subcooler, or hot steam from the hot gas line before entering the condenser. The refrigerant flow rate flowing through the pipes can be the entire condenser flow rate or a portion thereof, adjusted by a manual or automatic bypass valve controlled by the aforementioned input parameters. This allows the remaining liquid in the rising vapor flow to evaporate and be eliminated before leaving the evaporator.

[0091] For completeness, it's worth mentioning:

[0092] -Heat exchanger tubes can be plain tubes, finned tubes / ribbed tubes, or any type of tube with enhanced surface structure or porous coating to improve heat transfer performance in specific applications,

[0093] - the distribution system can be positioned on or through the support plate / tube plate, and

[0094] Single-pass, dual-pass, or multi-pass systems can be used with the described distribution system. Returning to the clear example provided above, it is apparent from this example that, in practical applications, it is optimal to distribute more refrigerant to the lower portion of the tube bundle, corresponding to the first passage of the fluid within the tubes, than to the upper portion. Another aspect of the invention provided herein addresses this issue.

[0095] The heat exchanger according to this aspect of the invention includes a shell, at least one bundle of heat exchanger tubes arranged in the shell, the heat exchanger tubes having a tube length defining a horizontal x-direction, and the heat exchanger tube bundle having a vertical extension defining a z-direction orthogonal to the x-direction, and at least one refrigerant distribution layer located above the at least one heat exchanger tube bundle, the at least one refrigerant distribution layer including perforated tubes having holes for discharging refrigerant to the heat exchanger tube bundle above which the refrigerant distribution layer is located.

[0096] According to this aspect of the invention, the heat exchanger further comprises a plurality of refrigerant distribution layers connected to at least one throttling / laminating device, such as an expansion valve, through which the refrigerant flows and, after passing through the at least one throttling / laminating device, is distributed between at least two refrigerant distribution layers. At least one of the two refrigerant distribution layers between which the refrigerant flow is distributed comprises a device for regulating the flow of refrigerant to the distribution layer.

[0097] In this way, the distribution of refrigerant within each heat exchanger tube bundle can be effectively controlled. Preferably, each refrigerant distribution layer includes a device for regulating refrigerant flow. Furthermore, preferably, a control system is provided to control the degree of opening of the device for regulating refrigerant flow to the distribution layer.

[0098] Obviously, the specific features and advantageous embodiments of this aspect of the invention can be easily combined with the specific features and advantageous embodiments of the first aspect of the invention, so that the advantageous embodiments of the first aspect of the invention can be directly transferred to this aspect of the invention, thereby having the same benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0099] Next, the present invention will be described in more detail with reference to the accompanying drawings, which illustrate possible embodiments of the present invention. The accompanying drawings show:

[0100] Figure 1 Shown is a typical usage structure of a heat exchanger.

[0101] Figure 2 A view showing a first embodiment of a heat exchanger is shown.

[0102] Figure 3 A view showing a second embodiment of a heat exchanger is shown.

[0103] Figure 4 Shown Figure 3 Cross-sectional view of the illustrated embodiment of the heat exchanger.

[0104] Figure 5a A first view of a refrigerant distribution layer is shown.

[0105] Figure 5b Shown Figure 5a A second view of the refrigerant distribution layer is shown.

[0106] Figure 5c Shown Figure 5b Zoomed in details.

[0107] Figure 6a A first enlarged view showing the distribution of refrigerant on the heat exchanger tubes is shown.

[0108] Figure 6b A second enlarged view showing the distribution of refrigerant on the heat exchanger tubes is shown.

[0109] Figure 6c A third enlarged view showing geometrical details of the distribution of the refrigerant on the heat exchanger tubes is shown.

[0110] Figure 7a Shown Figure 6aThe variation further illustrates the distribution of refrigerant on the heat exchanger tubes.

[0111] Figure 7b Various possible configurations of the hole groups are shown.

[0112] Figures 8a to 8c Shown Figure 4 Three variations of the heat exchanger shown.

[0113] Figure 9 Shown Figure 4 A further variant of the heat exchanger shown.

[0114] Figure 10 An alternative arrangement using a heat exchanger is shown, and

[0115] Figure 11 A view showing a third embodiment of a heat exchanger is shown. DETAILED DESCRIPTION

[0116] In the drawings, unless otherwise specified, identical components are designated by identical reference numerals. However, to improve the clarity of the drawings, not all reference numerals are shown in all drawings and in all possible locations.

[0117] Figure 1 Shows a typical use structure of a heat exchanger 1, 100, wherein two figures are used to illustrate Figure 2 Heat exchanger 1 and Figure 3 The heat exchanger 100 in FIG. 1 can be used in this structure. In the structure shown, the hot fluid enters from the left side of the heat exchanger 1, 100, is cooled by interacting with the refrigerant inside the heat exchanger 1, 100, and then leaves the heat exchanger 1, 100 from the right side. Figure 1 In the embodiment of FIG. 4 , the refrigerant is provided by a heat removal heat exchanger 2 and passes through a throttling / laminating device, here represented by an expansion valve 3 , before being fed into the refrigerant distribution layer of the heat exchanger.

[0118] It should be noted that in Figure 1 In the embodiment shown, the refrigerant flow is divided between two refrigerant distribution layers 130 and 150 after passing through the expansion valve 3, wherein each distribution layer includes a device 125, 145, which can be implemented as a valve, for example, for regulating the refrigerant flow to the corresponding distribution layer. The degree of opening of the device 125, 145 for regulating the refrigerant flow to the distribution layer is determined by Figure 1 The control system can use one or more parameters as set points to control, such as compressor inlet superheat, compressor outlet superheat, compressor input power, compressor capacity modulation or distributor pressure drop.

[0119] The refrigerant is then distributed through the refrigerant distribution layers 30, 130, and 150 of heat exchangers 1 and 100, where it contacts heat exchanger tubes 21, 121, and 141. As described in detail below, the fluid to be cooled flows within the heat exchanger tubes and evaporates during the cooling process. The resulting refrigerant vapor is drawn into compressor 4, compressed, and returned to heat-removing heat exchanger 2.

[0120] Figure 1 The main figure shows the shell of the heat exchanger 1, 100, and Figure 2 、 3 4 and 5 show their corresponding internal views, respectively, from which it can be seen that the heat exchanger 1, 100 is a horizontal tube falling film evaporator type heat exchanger. Inside the shell 10, 110 having a fluid inlet 11, 111, a fluid outlet 12, 112 and a refrigerant outlet 13, 113, at least one tube bundle 20, 120, 140 of heat exchanger tubes 21, 121, 141 is arranged. The fluid to be cooled is distributed to these tube bundles, such as Figure 2 and 3 As shown by the arrows at the corresponding fluid inlets 11 and 111.

[0121] Length L of heat exchanger tubes 21, 121, 141 t (Only in Figure 2 The tube bundle 20, 120, 140 is essentially a group of heat exchanger tubes 21, 121, 141; the space required in the vertical direction for a given group 20, 120, 140 defines its vertical extension H. tb 、H tb1 and H tb2 , and defines a vertical z direction orthogonal to the x direction. As can be seen from the figure, the tube length L t Exceeds the vertical extension H tb 、H tb1 and H tb2 This means that the refrigerant is distributed primarily as a falling film, rather than primarily as a liquid that is entrained and distributed by rising vapor.

[0122] In addition, if Figure 2 and Figure 3As shown, the horizontal tube falling film evaporator type heat exchangers 1, 100 each comprise at least one refrigerant distribution layer 30, 130, 150, which is located above the heat exchanger tubes 21, 121, 141 of at least one tube bundle 20, 120, 140. The distribution layer 30, 130, 150 comprises perforated tubes 31, 131, 151 for discharging refrigerant to the heat exchanger tubes 21, 121, 141 of the tube bundle 20, 120, 140, which is located above the refrigerant distribution layer 30, 130, 150. Thus, refrigerant is discharged from the refrigerant distribution layer at multiple locations through perforations of the perforated tubes 31, 131, 151 and drops or sprays onto the heat exchanger tubes 21, 121, 141 located below. If parts of the refrigerant do not evaporate during the interaction with the heat exchanger tubes 21, 121, 141, liquid refrigerant can be present in the bottom of the shell 10, 110, as shown in Figure 4 As shown, the refrigerant level RL is indicated.

[0123] It is to be noted that the longitudinal y-direction of the perforated tubes 31, 131, 151 is orthogonal to the longitudinal x-direction defined by the heat exchanger tubes 21, 121, 141 and the vertical z-direction defined by the respective extension H tb , H tb1 and H tb2 , as shown in Figure 2 and Figure 3 orthogonal to the plane of the paper.

[0124] Figures 5a to 5c and Figures 6a to 6c The details of the refrigerant distribution layers 30, 130, 150 and the way they distribute refrigerant to the heat exchanger tubes 21, 121, 141 are described in detail with respect to the refrigerant distribution layer 130 as an example, respectively. As can be seen from these figures, the shown embodiments of the refrigerant distribution layers 30, 130, 150 comprise a central refrigerant supply tube 32, 132, 152 extending parallel to the heat exchanger tubes 21, 121, 141 and a plurality of perforated tubes 31, 131, 151, the longitudinal axes of which define a horizontal y-direction orthogonal to the x-direction defined by the heat exchanger tubes 21, 121, 141. The perforated tubes 31, 131, 151 extend opposite to each other from opposite sides of the central refrigerant supply tube 32, 132, 152. More specifically, in the present embodiments, the perforated tubes 31, 131, 151 are directly connected to the respective central supply tube 32, 132, 152, forming an antenna-like structure.

[0125] However, it is to be emphasized that the refrigerant distribution layers having the features described in claim 1 are not limited to the structures shown in Figures 2 to 5c To illustrate this, the refrigerant distribution layers 30, 130, 150 are shown in Figures 8a to 8c respectively. Figure 4The three variants 130', 150', 130", 150" and 130'", 150'" of the refrigerant distribution layer of the illustrated heat exchanger 100 variants 100', 100" and 100'". Since all other components are identical to the embodiments of Figure 4 , some additional aspects of which will be discussed below, the remaining reference numerals are omitted except for the reference numerals of the housing 10, which are identical in all variants of Figure 4 and Fig. 8.

[0126] Figure 4 The first difference between the variants illustrated in Fig. 8 is that each perforated tube 131', 151', 131", 151", 131'", 151'" illustrated in Fig. 8 extends over the entire tube bundle (in the y-direction) and is supplied with refrigerant from one side.

[0127] The difference between the variants illustrated in Fig. 8 is the way in which the perforated tubes 131', 151', 131", 151", 131'", 151'" are supplied with refrigerant. In the refrigerant supply systems 130' and 150', this is achieved by a common supply line 132', 152' which is located inside the housing 10 and is supplied from outside the housing 10. In the refrigerant supply system 130", this is achieved by passing the individual perforated tubes 131", 151" through the housing 10 and supplying them with refrigerant separately. In the refrigerant supply system 130'", this is achieved by passing the individual perforated tubes 131'", 151'" through the housing 10 and supplying them with refrigerant using a common supply line 132'", 152'".

[0128] It is clear from Figure 5c and Figure 6a that the perforations of the perforated tubes 31, 131, 151 are formed by a plurality of holes 133a.1, 133a.2, 133a.3, 133a.4, 133a.5, 133a.6, 133a.7 arranged in hole groups 133a, 133b, 133c, 133d. The plurality of holes of each hole group 133a, 133b, 133c, 133d are arranged on a circumference of a vertical xz plane which passes through a heat exchanger tube 21, 121, 141, 121a.1 of the tube bundle 20, 120, 140 and is located above the respective heat exchanger tube 121a.1, 121a.2, 121b.1, 121b.2, 141a.1, 141a.2, 141b.1, 141b.2 of the tube bundle 20, 120, 140. Ideally, this plane passes through the center line of the heat exchanger tube such that the discharged refrigerant is able to flow over the entire surface of the heat exchanger tube, thereby achieving optimal heat transfer.

[0129] In Figure 6a and Figure 6cAs can be immediately seen in the diagram, the plurality of holes 133a.1, 133a.2, 133a.3, 133a.4, 133a.5, 133a.6, and 133a.7 belonging to hole group 133a are arranged circumferentially in a perpendicular xz plane passing through the heat exchanger tubes 21, 121, 141, and 121a.1 of tube bundles 20, 120, and 140. Refrigerant exits perforated tube 131 in the form of multiple jets and is thus immediately distributed along the longitudinal x-direction of heat exchanger tube 121a.1, resulting in more uniform refrigerant distribution and a better cooling effect. Indeed, by selecting an appropriate distance A between adjacent perforated tubes 131, substantially uniform refrigerant distribution across heat exchanger tube 121a can be achieved in the portion of heat exchanger 121a directly supplied by each perforated tube 131.

[0130] Since a plurality of hole groups 133a, 133b, 133c, 133d are provided along the perforated tube 131 and are located above the corresponding heat exchanger tubes 121a.1, 121a.2, 121b.1, 121b.2, 141a.1, 141a.2, 141b.1, 141b.2 in the heat exchanger tubes 21, 121, 141 of the tube bundle 20, 120, 140, Figure 6b and Figure 4 As can be clearly seen in FIG, this effect is achieved for each of the heat exchanger tubes in the top two rows of heat exchanger tubes 21, 121, 141 of a given tube bundle 20, 120, 140. It is thus possible to distribute the refrigerant more optimally and achieve a better cooling effect than with the distribution plates known from the prior art, in particular by using several degrees of freedom, in particular with regard to the number and grouping of perforations belonging to a group, their shape and diameter, and the distance between adjacent perforated tubes, in order to ultimately optimize the refrigerant distribution.

[0131] Figure 7a and 7b Some of these degrees of freedom are shown visually. Figure 7a In the embodiment, the distance between two adjacent pairs of perforated tubes 131a, 131b / 131b, 131c / 131c, and 131d varies. Furthermore, the hole group of perforated tubes 131a and 131b includes seven holes, while the hole group of perforated tubes 131c and 131d includes five holes. This results in a change in the cross-sectional length of heat exchanger tube 121a' that receives refrigerant from the corresponding perforated tubes 131a, 131b, 131c, and 131d.

[0132] Figure 7bAnother variation is shown, illustrating different possible hole configurations within hole groups 233a, 233b, 233c, 233d, and 233e of perforated tube 231. In the figure, the cylindrical wall of perforated tube 231 is rolled up to form a square. Hole group 233a consists of seven equally spaced circular holes. Hole group 233b consists of seven equally spaced slit-like holes. Hole group 233c consists of seven equally spaced rectangular holes. Hole group 233d consists of seven circular holes with varying spacing. Hole group 233e consists of five circular holes with varying spacing. Thus, the shape and number of holes, as well as the distance between them, can be varied. Of course, the hole size can also be varied, and holes of different shapes can be combined within a hole group. By modifying the perforated tubes and their arrangement relative to each other, specific heat transfer requirements and objectives can be met. For example, more refrigerant can be distributed to areas with higher ΔT (inlet of the fluid to be cooled), or a larger number of heat exchange tubes can be arranged below a specific hole group (near the shell where there are fewer tubes and less refrigerant can be evaporated than in the center of the heat exchanger).

[0133] according to Figure 4 , Figure 8 and Figure 9 In one aspect of some illustrated embodiments of the present invention, the vertical distance between adjacent rows of heat exchanger tubes 121a.1, 121a.2, 121b.1, 121b.2, ... and 141a.1, 141a.2, 141b.1, 141b2 of the heat exchanger tubes 121, 141 of the respective tube bundles 120, 140 varies; in particular, the distance can gradually increase from bottom to top. This configuration can limit the velocity of rising steam, which tends to increase with increasing altitude due to an increase in total steam flow.

[0134] Figure 9 Another variant 100" of the heat exchanger 100 is shown. Similar to the case of FIG8 , only reference numerals related to the changed parts are added in the figure; Figure 9 The remaining features shown are similar to Figure 4 The heat exchangers 100 and 100" are identical and therefore not mentioned separately. The difference between heat exchangers 100 and 100" lies in the shape of shell 10", which is rectangular, or more precisely, substantially square. This allows for the same number of heat exchanger tubes in each row, making it easier to operate in pure falling film mode (rather than mixed mode), minimizing the total refrigerant charge. This solution is best suited for low-pressure refrigerants such as R1233zd and R1234ze, as this shape has poor pressure resistance.

[0135] Finally, if Figure 3 and Figure 4As shown, heat exchanger 100 also includes an active demister 160, an integrated regenerative heat exchanger located above the topmost refrigerant distribution layers 130, 131, and 132. This allows for more reliable complete evaporation of the refrigerant entering the compressor, even under extreme operating conditions. The heat medium flowing within the tubes of active demister 160 or the integrated heat exchanger can be liquid refrigerant from the condenser or an additional subcooler, or hot steam from the hot gas line before entering the condenser. The refrigerant flow rate within the tubes can be the full condenser flow rate or a portion of the flow rate via a manual or automatic bypass valve controlled by input parameters as described above. The heat medium enters the integrated regenerative heat exchanger through inlet connection 161, is distributed within the heat exchanger tubes, and is discharged after cooling through outlet connection 162. During the heat exchange process, the heat medium transfers heat to the rising refrigerant vapor flow generated by the heat exchanger tubes, which contacts the outer surface of the integrated regenerative heat exchanger tubes, with or without fins. In this way, the remaining liquid portion of the rising vapor flow can be evaporated and eliminated before leaving the evaporator.

[0136] Figure 10 Another configuration of heat exchanger 200 is shown. In this configuration, heat exchanger 200 operates with two refrigerant circuits. Therefore, refrigerant is provided by two different heat removal heat exchangers 202a and 202b.

[0137] Heat exchanger 200 is a third embodiment of a heat exchanger, and its structure in this embodiment is as follows: Figure 11 In a shell 210 having a fluid inlet 211, a fluid outlet 212 and two refrigerant outlets 213a, 213b, heat exchanger tubes 221, 241 of two tube bundles 220, 240 are arranged, and the fluid to be cooled is distributed to these tube bundles, as shown in FIG. Figure 10 The heat exchanger 200 includes two pairs of layers 230a, 250a and 230b, 250b, which are respectively arranged above the corresponding sections of the tube bundles 220, 240. Each cooling layer 230a, 230b, 250a and 250b can be implemented in a similar manner to the above.

[0138] from Figure 11 As can be clearly seen in FIG, the refrigerant distribution layers 230a, 230b and 250a, 250b are respectively arranged horizontally adjacent to each other and are arranged above different sections of the same tube bundle 220, 240 of the heat exchanger tubes 221, 241.

[0139] In contrast, the refrigerant distribution layers 230a, 250a and 230b, 250b are respectively arranged vertically above and below each other and away from each other in the vertical z-direction, so that each refrigerant distribution layer 230a, 230b, 250a, 250b is arranged above the heat exchanger tubes 221, 241 of at least one tube bundle relative to the heat exchanger tubes 221, 241 of the tube bundles 220, 240.

[0140] like Figure 10 As shown, after the refrigerant passes through the corresponding throttling / lamination devices (here represented as expansion valves 203a and 203b), the refrigerant is sent to the corresponding refrigerant distribution layers 230a, 250a, 230b, 250b through independent devices 225a, 225b, 245a, 245b, which are used to adjust the refrigerant flow flowing to the distribution layers 230a, 250a, 230b, 250b so that the refrigerant flow can be controlled individually, preferably by a control system (not shown).

[0141] Back to Figure 10 In the device shown, the hot fluid enters from the lower right side of the heat exchanger 200, interacts with the refrigerant inside the heat exchanger 200 to cool, and then leaves the heat exchanger 200 from the upper right side. Figure 10 In the embodiment, the refrigerant is provided by two different heat removal heat exchangers 202a and 202b and passes through a throttling / laminating device (here represented as expansion valves 203a and 203b) before being fed into the refrigerant distribution layer of the heat exchanger.

[0142] However, it should be noted that in this embodiment, before the refrigerant expands, the refrigerant passes through active demisters 260a, 260b in liquid form (and therefore hotter than the temperature of the evaporated refrigerant), which act as heating units to evaporate the remaining liquid refrigerant content in the exhaust vapor located inside the shell 210.

[0143] The refrigerant vapor thus produced is purified and then sucked into the corresponding compressors 204a, 204b, compressed and sent to the corresponding heat removal heat exchangers 202a, 202b.

[0144] Description of reference numerals:

[0145] 1. 100, 100', 100", 100'', 100'": heat exchanger

[0146] 2. 202a, 202b: heat removal heat exchanger 3. 203a, 203b: expansion valve 4. 204a, 204b: compressor 10. 10", 110, 210: shell 11. 111, 211: fluid inlet 12. 112, 212: fluid outlet 13. 113, 213a, 213b: refrigerant outlet

[0147] 20, 120, 140, 220, 240: tube bundle

[0148] 21, 121, 141, 221, 241: heat exchanger tube

[0149] 121a.1, 121a.2, 121b.1, 121b.2: heat exchanger tube

[0150] 141a.1, 141a.2, 141b.1, 141b.2: heat exchanger tube

[0151] 30, 130, 130', 130", 130": refrigerant distribution layer

[0152] 150, 150', 150", 150": refrigerant distribution layer

[0153] 31, 131, 131', 131", 131": perforated tube

[0154] 151, 151', 151", 151": perforated tube

[0155] 32, 132, 152: feed tube

[0156] 132', 132", 152, 152', 152": feed line

[0157] 133a, 133b, 133c, 133d: hole group

[0158] 133a.1, 133a.2, 133a.3, 133a.4, 133a.5, 133a.6, 133a.7: hole

[0159] 125, 145, 225a, 225b, 245a, 245b: flow regulating device

[0160] 160, 260a, 260b: active mist eliminator 161: inlet connection 162: outlet connection

[0161] 230a, 230b, 250a, 250b: refrigerant distribution layer

[0162] 233a, 233b, 233c, 233d, 233e: hole group H tb , H tb1 , H tb2 : extension length L t : tube length A: distance M: center RL: refrigerant level

Claims

1. A horizontal tube falling film evaporator type heat exchanger (1, 100, 200), comprising: Housing (10, 110, 210), The heat exchanger tubes (21, 121, 141, 221, 241) of at least one tube bundle (20, 120, 140, 220, 240) are arranged in the shell (10, 110, 210), and the tube length (L) of the heat exchanger tubes (21, 121, 141, 221, 241) is t ) defines the horizontal x direction and the vertical extension length (H) of the heat exchanger tubes (21, 121, 141, 221, 241) of the tube bundle (20, 120, 140, 220, 240) tb , H tb1 , H tb2 ) defines a z direction orthogonal to the x direction, and At least one refrigerant distribution layer (30, 130, 150, 230a, 230b, 250a, 250b) is located above the heat exchanger tubes (21, 121, 141, 221, 241) of at least one tube bundle (20, 120, 140, 220, 240), and the at least one refrigerant distribution layer (30, 130, 150, 230a, 230b, 250a, 250b) includes a plurality of holes (133a.1, 133a.2, 133a.3, 133a.4, 133a.5, 133a.6, 133a.7) of the perforated tube (31, 131, 151) for supplying a refrigerant distribution layer (30, The heat exchanger tubes (21, 121, 141, 221, 241) of the tube bundle (20, 120, 140, 220, 240) of the tube bundle (130, 150, 230a, 230b, 250a, 250b) discharge refrigerant, characterized in that The longitudinal axes of at least some of the perforated tubes (31, 131, 151) define a horizontal y-direction orthogonal to the x-direction defined by the heat exchanger tubes (21, 121, 141, 221, 241), and the perforations of the perforated tubes (31, 131, 151) consist of a plurality of holes (133a.1, 133a.2, 133a.3, 133a.4, 133a.5, 133a.6, 133a.7) arranged in hole groups (133a, 133b, 133c, 133d), wherein each hole group (133a, 133b, 133c, 133d) is arranged on a circumference provided on the heat exchanger tubes (21, 121, 141, 221, 241) passing through the tube bundle (20, 120, 140, 220, 240). ), and wherein a plurality of holes in a given hole group (133a, 133b, 133c, 133d) are located in corresponding heat exchanger tubes (121a.1, 121a.2, 121b.1, 121b.2, 121b.2) of the heat exchanger tubes (21, 121, 141, 221, 241) of the tube bundle (20, 120, 140, 220, 240) 41a.1, 141a.2, 141b.1, 141b.2) so that the refrigerant discharged from a given hole group (133a, 133b, 133c, 133d) propagates toward the heat exchanger tubes (121a.1, 121a.2, 121b.1, 121b.2, 141a.1, 141a.2, 141b.1, 141b.2).

2. The heat exchanger (1, 100, 200) according to claim 1, characterized in that The number (n) of the plurality of holes (133a.1, 133a.2, 133a.3, 133a.4, 133a.5, 133a.6, 133a.7) of each hole group h ) is between 5 and 11.

3. The heat exchanger (1, 100, 200) according to claim 1 or 2, characterized in that The number (n) of the plurality of holes (133a.1, 133a.2, 133a.3, 133a.4, 133a.5, 133a.6, 133a.7) of each hole group h ) is an odd number, and the positions of the multiple holes (133a.1, 133a.2, 133a.3, 133a.4, 133a.5, 133a.6, 133a.7) of each hole group are symmetrical with respect to the central hole (133a.4), and the central hole is located at the bottom of the perforated tube (131), and the bottom of the perforated tube (131) directly faces the heat exchanger tube (121) located below the multiple holes (133a.1, 133a.2, 133a.3, 133a.4, 133a.5, 133a.6, 133a.7) of the hole group.

4. The heat exchanger (1, 100, 200) according to any one of claims 1 to 3, characterized in that The plurality of holes (133a.1, 133a.2, 133a.3, 133a.4, 133a.5, 133a.6, 133a.7) in a given hole group (133a) are arranged in such a way that a corresponding first straight line (s1, s2, s3, s4, s5, s6) passing through the first hole (133a.1, 133a.2, 133a.3, 133a.4, 133a.5, 133a.6) and the center (M) of the perforated tube (131) and a corresponding first straight line (s1, s2, s3, s4, s5, s6) located at the given hole group (133a) are arranged in such a way that a corresponding first straight line (s1, s2, s3, s4, s5, s6) passing through the first hole (133a.1, 133a.2, 133a.3, 133a.4, 133a.5, 133a.6) and the center (M) of the perforated tube (131) are arranged in such a way that a corresponding first straight line (s1, s2, s3, s4, s5, s6) passing through the first hole (133a.1, 133a.2, 133a.3, 133a.4, The corresponding distances (x) between a first intersection point formed by the heat exchanger tube (121a.1) below the hole group (133) and a second intersection point formed by a corresponding second straight line (s2, s3, s4, s5, s6, s7) passing through the adjacent second hole (133a.2, 133a.3, 133a.4, 133a.5, 133a.6, 133a.7) and the center (M) of the perforated tube (131) and the heat exchanger (121a.1) located below the hole group (133) are 12 , x 23 , x 34 , x 45 , x 56 , x 67 ) are equal.

5. The heat exchanger (1, 100, 200) according to any one of claims 1 to 4, characterized in that Satisfy the condition 1<(A / D pp ) / n h <3, where A defines the distance between the centers (M) of two adjacent perforated tubes (131), the longitudinal axes of the two adjacent perforated tubes defining a horizontal y direction orthogonal to the x direction defined by the heat exchanger tubes (21, 121, 141, 221, 241), D pp is the diameter of the perforated tube (131) and n h It is the number of the plurality of holes (133a.1, 133a.2, 133a.3, 133a.4, 133a.5, 133a.6, 133a.7) belonging to a hole group (133a).

6. The heat exchanger (1, 100, 200) according to any one of claims 1 to 5, characterized in that The at least one refrigerant distribution layer (30, 130, 150, 230a, 230b, 250a, 250b) comprises a central refrigerant supply tube (32, 132, 152) extending parallel to the heat exchanger tubes (21, 121, 141) and a plurality of perforated tubes (31, 131, 151), wherein the longitudinal axes of the perforated tubes define a horizontal y-direction orthogonal to the x-direction defined by the heat exchanger tubes (21, 121, 141), wherein the perforations of the perforated tubes (31, 131, 151) are composed of a plurality of holes (133a.1, 133a.2, 133a.3, 133a.4, 133a.5, 133a.6, 133a.7) arranged in hole groups (133a, 133b, 133c, 133d) The invention relates to a heat exchanger bundle (20, 120, 140, 220, 240) comprising: a heat exchanger tube (21, 121, 141, 221, 241) and a heat exchanger tube (21, 121, 141, 221, 241) of the bundle (20, 120, 140, 220, 240); a heat exchanger tube (21, 121, 141, 221, 241) of the bundle (20, 120, 140, 220, 240); and a heat exchanger tube (121a.1, 121a.2, 121b.1, 121b.2, 141a.1, 141a.2, 141b.1, 141b.2) of the bundle (20, 120, 140, 220, 240).

7. The heat exchanger (1, 100, 200) according to any one of claims 1 to 6, characterized in that The heat exchanger (1, 100, 200) includes a plurality of refrigerant distribution layers (30, 130, 150, 230a, 230b, 250a, 250b).

8. The heat exchanger (1, 100, 200) according to claim 7, characterized in that The heat exchanger (1, 100, 200) includes a plurality of horizontally adjacently arranged refrigerant distribution layers (30, 130, 150, 230a, 230b, 250a, 250b).

9. The heat exchanger (1, 100, 200) according to claim 8, characterized in that At least two horizontally adjacently arranged refrigerant distribution layers (30, 130, 150, 230a, 230b, 250a, 250b) are arranged above different sections of heat exchanger tubes (21, 121, 141, 221, 241) of the same tube bundle (20, 120, 140, 220, 240).

10. The heat exchanger (1, 100, 200) according to any one of claims 7 to 9, characterized in that The heat exchanger (1, 100, 200) comprises a plurality of refrigerant distribution layers (30, 130, 150, 230a, 230b, 250a, 250b) arranged one above the other and away from each other in a vertical z-direction, and further comprises a plurality of heat exchanger tubes (21, 121, 141, 221, 241) of a tube bundle (20, 120, 140, 220, 240) arranged one above the other in a vertical z-direction, wherein the plurality of refrigerant distribution layers (30, 130, 150, 230a, 230b, 250a, 250b) are arranged one above the other and away from each other. 230b, 250a, 250b) and the heat exchanger tubes (21, 121, 141, 221, 241) of the plurality of tube bundles (20, 120, 140, 220, 240) are arranged in such a manner that each refrigerant distribution layer (30, 130, 150, 230a, 230b, 250a, 250b) is arranged above the heat exchanger tubes (21, 121, 141, 221, 241) of at least one tube bundle (20, 120, 140, 220, 240).

11. The heat exchanger (1, 100, 200) according to any one of claims 7 to 10, characterized in that The heat exchanger (1, 100, 200) is connected to a throttling / laminating device (3, 203a, 203b) through which the refrigerant flows, and the refrigerant flow passing through the throttling / laminating device (3, 203a, 203b) is distributed among the refrigerant distribution layers (30, 130, 150, 230a, 230b, 250a, 250b).

12. The heat exchanger (1, 100, 200) according to claim 11, characterized in that Each distribution layer (30, 130, 150, 230a, 230b, 250a, 250b) includes means (125, 145, 225a, 225b, 245a, 245b) for regulating the flow of refrigerant to the distribution layer (30, 130, 150, 230a, 230b, 250a, 250b).

13. The heat exchanger (1, 100, 200) according to claim 12, characterized in that The opening degree of the device (125, 145, 225a, 225b, 245a, 245b) for regulating the flow of refrigerant to the distribution layer (30, 130, 150, 230a, 230b, 250a, 250b) is adjusted by the control system.

14. The heat exchanger (1, 100, 200) according to any one of claims 10 to 13, characterized in that The vertical distance between adjacent rows of heat exchanger tubes (121a.1, 121a.2, 121b.1, 121b.2, 141a.1, 141a.2, 141b.1, 141b.2) of the heat exchanger tubes (121, 141, 221, 241) forming the tube bundle (120, 140, 220, 240) varies and advantageously increases gradually from bottom to top.

15. The heat exchanger (1, 100, 200) according to any one of claims 1 to 14, characterized in that The cross section of the housing (10, 110, 210) in the yz plane is rectangular or square.

16. The heat exchanger (1, 100, 200) according to any one of claims 1 to 15, characterized in that A heating unit for evaporating the remaining refrigerant liquid component in the exhaust vapor (160, 260a, 260b) is located above the uppermost refrigerant distribution layer (130, 230a, 230b).

17. The heat exchanger (1, 100, 200) according to any one of claims 1 to 16, characterized in that At least some of the plurality of holes (133a.1, 133a.2, 133a.3, 133a.4, 133a.5, 133a.6, 133a.7) have different shapes and / or sizes.

18. The heat exchanger (1, 100, 200) according to any one of claims 1 to 17, characterized in that At least some of the hole groups (133a, 133b, 133c, 133d) include different numbers of holes (133a.1, 133a.2, 133a.3, 133a.4, 133a.5, 133a.6, 133a.7).

19. The heat exchanger (1, 100, 200) according to the preamble of claim 1, characterized in that A heat exchanger (1, 100, 200) comprises a plurality of refrigerant distribution layers (30, 130, 150, 230a, 230b, 250a, 250b), wherein the heat exchanger (1, 100, 200) is connected to at least one throttling / laminating device (3, 203a, 203b), through which refrigerant flows, wherein the refrigerant flow after passing through the at least one throttling / laminating device (3, 203a, 203b) is divided between at least two refrigerant distribution layers (30, 130, 150, 230a, 230b, 250a, 250b), and wherein at least one of the plurality of refrigerant distribution layers (30, 130, 150, 230a, 230b, 250a, 250b) between which the refrigerant flow is divided comprises means (125, 145, 225a, 225b, 245a, 245b) for regulating the flow of refrigerant to the distribution layer (30, 130, 150, 230a, 230b, 250a, 250b).

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