Heat exchanger core and plate heat exchanger
The heat exchanger core with alternating ridges and protrusions optimizes strength, pressure resistance, and heat transfer performance by enhancing fluid distribution and turbulence, addressing the limitations of existing plate heat exchanger designs.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- ALFA LAVAL CORP AB
- Filing Date
- 2025-12-05
- Publication Date
- 2026-06-25
AI Technical Summary
Existing plate heat exchangers face challenges in achieving a balance between strength, pressure resistance, heat transfer performance, and fluid distribution, with current patterns often compromising on one or more of these aspects.
A heat exchanger core design featuring alternating ridges and protrusions on heat exchanger plates, where ridges form joints with valley regions, providing an elongated contact area and directing fluids efficiently, while protrusions enhance turbulence and distribution.
The design enhances strength, pressure resistance, and heat transfer efficiency with reduced pressure drop, allowing for improved fluid distribution and increased effective heat transfer area.
Smart Images
Figure EP2025085670_25062026_PF_FP_ABST
Abstract
Description
[0001] HEAT EXCHANGER CORE AND PLATE HEAT EXCHANGER
[0002] Technical Field
[0003] The invention relates to the field of heat exchangers. More particularly, it is related to a core for a plate heat exchanger and a plate heat exchanger comprising such a core.
[0004] The core has first heat exchanger plates, and second heat exchanger plates alternatingly stacked onto each other.
[0005] Plate heat exchangers are used in numerous applications where heat is to be transferred from one fluid to another or vice versa.
[0006] A typical plate heat exchanger includes a plate package formed of stacked heat exchanger plates. Generally, a number of first heat exchanger plates and a number of second heat exchanger plates are stacked in an alternating fashion and joined to each other. In this way a first plate interspace is formed between each pair of adjacent first and second heat exchanger plates and a second plate interspace between each pair of adjacent second and first heat exchanger plates. The first plate interspaces and the second plate interspaces are typically separated from each other and are designed to receive a respective fluid between which fluids heat is to be exchanged. To this end, respective inlet and outlet ports are typically provided to the first plate interspaces and to the second plate interspaces.
[0007] The heat exchanger plates of plate heat exchangers are generally provided with some form of pattern at least in an area forming a heat transfer area. Such pattern is typically pressed into the material forming the heat exchanger plates by deforming the heat exchanger plates. However, such pattern can also be embossed or etched into the material forming the heat exchanger plates.
[0008] In plate heat exchanger plates the pattern serves a plurality of purposes. A first typical purpose of the pattern is to define the height of an associated plate interspace by the pattern of one heat exchanger plate contacting adjacent heat exchanger plates. A second typical purpose of the pattern is to provide a tailored contact surface between adjacent heat exchanger plates such that the heat exchanger plates can be fixed to each other in a multitude of locations and not only regions closer to the edge of the heat exchanger plates. In this way, the plate heat exchanger can be made sturdier and more pressure resistant. A third general purpose of the pattern is to improve the performance of the heat exchanger in terms of heat exchange. This purpose is generally achieved by tailoring the surface area of the pattern to maximize its effective heat transfer area. Moreover, this purpose is generally achieved by introducing pattern features causing turbulence in the fluid passing by the pattern. In addition, all of the above purposes are to be achieved with an acceptable pressure drop of the fluid passing by the pattern.
[0009] The above purposes of the patten are not easily accounted for in the same pattern. In this regard, a pattern promoting a strong fixing of a heat exchanger plate to adjacent heat exchanger plates generally results in drawbacks in terms of a reduced performance in terms of heat exchange as well as an increased pressure drop. Similarly, a pattern promoting a maximized heat transfer area generally results in a less strong fixing of a heat exchanger plate to adjacent heat exchanger plates. Moreover, a pattern promoting excessive turbulence typically results in an undesired pressure drop with a reduced flow as a consequence.
[0010] To this end, it has been suggested to provide patterns which aims at optimizing strength and performance simultaneously. In this regard, it has been proposed to provide complex patterns formed of various features, where each feature seeks to optimize a certain property of the plate heat exchanger.
[0011] Even though currently available patterns provide efficient plate heat exchangers in terms of strength and performance, there is still a room for improvement how such patterns are shaped to achieve an even better functionality, but also to increase the longevity of the heat plate heat exchanger.
[0012] With the above in mind, it is an object of the present invention to provide an improved heat exchanger core for a plate heat exchanger as well a plate heat exchanger including a heat exchanger core.
[0013] Another objective is to provide such a heat exchanger core which is stronger.
[0014] Another objective is to provide such a heat exchanger core which is more pressure resistant.
[0015] Another object is to provide such a plate heat exchanger which is less prone to cracking.
[0016] Another objective is to provide such a heat exchanger core which is less prone to cracking.
[0017] Another objective is to provide such a heat exchanger core which has an improved life-time. Another objective is to provide such a heat exchanger core which has an increased performance in terms of heat transfer.
[0018] Another objective is to provide such a heat exchanger core which has an increased performance in terms of heat transfer with at relatively speaking low pressure drop.
[0019] Another objective is to provide such a heat exchanger core in which the heat transfer fluids are more evenly distributed.
[0020] Another object is to provide such a plate heat exchanger which is more cost- effective.
[0021] To achieve at least one of the above objects and also other objects that will be evident from the following description, a heat exchanger core for a plate heat exchanger, having the features defined in claim 1 , is provided according to the present inventive concept. A plate heat exchanger including a heat exchanger core for a plate heat exchanger is provided according to claim 15.
[0022] More specifically, according to a first aspect, there is provided a heat exchanger core for a plate heat exchanger comprising: first heat exchanger plates and second heat exchanger plates alternatingly stacked onto each other in a vertical direction, and extending in parallel to a horizontal extension plane, wherein each of one of a first heat exchanger plate and an adjoining second heat exchanger plate comprises a heat exchange area provided with a heat transfer pattern, wherein the heat transfer pattern comprises ridges protruding a first height in the vertical direction, and protrusions protruding a second height, in the vertical direction, wherein the ridges are arranged one after the other along a first ridge line and a second ridge line, wherein ridges of the first ridge line are arranged to opposite ridges of the second ridge line, thereby forming a respective valley region in between each pair of opposite ridges, the first and the second ridge lines extending in parallel to each other and to the horizontal extension plane, wherein the protrusions are arranged one after the other along a protrusion line, extending in between the first and second ridge lines, and being parallel to the first and second ridge lines and to the horizontal extension plane, wherein the protrusions are offset with respect to the ridges along the protrusion line, wherein the first heat exchanger plate is joined to the second heat exchanger plate by joints, each joint being formed at an interface between a respective ridge of the first heat exchanger plate and a respective valley region of the second heat exchanger plate, and wherein the first height is greater than the second height such that a space is formed along the protrusion line.
[0023] Hereby an improved heat exchanger core for a plate heat exchanger is provided.
[0024] By providing a heat transfer pattern which includes a combination of ridges and protrusions arranged along parallel ridge lines and protrusion lines, respectively, where the ridges are used for joint formation, and where the ridges are higher such that a space is formed along the protrusion lines, a stronger heat exchanger core having an improved performance in terms of heat exchange may be achieved. More specifically, joints of an elongated shape may be formed at an interface between a respective ridge of a first heat exchanger plate and a respective valley region of a second heat exchanger plate. Owing to the fact that the joints are formed between a ridge and a valley region, the joints will have an elongated shape along an extension of the ridge which results in a stronger joint as compared to e.g. state of the art joints between crossing patterns features, such as in fish bone patterns. In other words, a larger contact area may be achieved at each joint by the joints being formed at an interface between a respective ridge of a first heat exchanger plate and a respective valley region of a second heat exchanger plate. Further, by the ridges having a greater height such that a space is formed along the protrusion lines, several advantages are achieved. In this way, the heat transfer fluids may efficiently be directed to the valley regions in between each pair of opposite ridges. That is, the heat transfer fluids may efficiently be directed under and over the joints or contact points of adjacent heat exchanger plates. Further, in this way the flow disturbance and hence the turbulence in the heat transfer fluids may be increased which results in a more efficient heat transfer. Furthermore, in this way, the total area efficiently contributing to the heat transfer between the heat transfer fluids may be increased. In other words, the total effective heat transfer area may be increased.
[0025] It should be noted that within the context of this application the term “ridge” may mean any pattern feature protruding from a surface of a heat exchanger plate and having an elongated shape in the sense that the ridge has a greater extension in one direction being parallel to the horizontal extension plane than in a perpendicular direction also being parallel to the horizontal extension plane. It should be noted that within the context of this application the term “protrusion” may mean any pattern feature protruding from a surface of a heat exchanger plate and having substantially equal extensions in perpendicular directions being parallel to the horizontal extension plane. Thus, within the context of this application a ridge is more elongated than a protrusion. Further, both a ridge and a protrusion represents a feature protruding from a surface of a heat exchanger plate in a common direction in the sense that they both have a component of extension being perpendicular to the surface at hand. Thus, both a ridge and a protrusion may be regarded as a dimple when view form an opposite side of the heat exchanger plate at hand given a pressed heat transfer pattern.
[0026] It should be noted that within the context of this application the terms “first height” and “second height” may mean any height or distance in the vertical direction above a base plane of a heat exchanger plate. In this regard, the base plane may be any plane being parallel to the horizontal extension plane of the heat exchanger plate which is located below tops of the ridges and protrusions respectively. In practice, the first height and the second height may be related to a horizontal extension plane in which bottoms of the valley regions are located.
[0027] It should be noted that within the context of this application the terms “ridge line” may mean any line along which the ridges are arranged one after the other.
[0028] It should be noted that within the context of this application the term “protrusion line” may mean any line along which the protrusions are arranged one after the other.
[0029] A respective further valley region may be formed in between consecutive ridges of the first and second ridge lines, which is advantageous in that the heat transfer fluids may be even more efficiently directed to the valley regions in between each pair of opposite ridges. Thus, the heat transfer fluids may be even more efficiently directed under and over the joints or contact points of adjacent heat exchanger plates resulting in a further increased performance in terms of heat transfer.
[0030] The valley regions and the additional valley regions may be arranged in a common valley plane being parallel to the horizontal extension plane, which is advantageous in that the performance in terms of heat transfer may be further increased. In practice, by the valley regions and the additional valley regions being arranged in a common valley plane, the surface area of the heat transfer pattern may be increased, thus resulting in an increased heat transfer. At the same time, a flow of the heat transfer fluids may be promoted.
[0031] A length extension of each ridge along the associated first or second ridge line may correspond to at least 2 times, such as at least 1,5 to 5 times, of a width extension of the ridge transverse the associated first or second ridge line, which is advantageous in that strong joints between adjoining heat exchanger plates may be achieved while at the same time allowing for that the heat transfer fluids may be efficiently guided along the valley regions.
[0032] Ridges of the first ridge line may be arranged directly opposite ridges of the second ridge line, which is advantageous in that a periodic pattern allowing for an increased strength of the heat exchanger core may be provided. In practice, when the ridges of the first ridge line are aligned with the ridges of the second ridge line by being directly opposite each other, equidistant distances between adjacent joints may be achieved which allows for an overall increased strength.
[0033] The ridges may be arranged at a uniform pitch along the first and second ridge lines, which is advantageous in that a periodic pattern allowing for an increased strength of the heat exchanger core may be provided. In practice, when the ridges of the first ridge line and the ridges of the second ridge line are arranged at a uniform pitch, equidistant distances between adjacent joints may be achieved which allows for an overall increased strength.
[0034] The protrusions may be arranged at the uniform pitch along the protrusion line, which is advantageous in that a uniform distribution of the heat transfer fluids may be achieved. In practice, the heat transfer fluids may be even more efficiently directed to the valley regions in between each pair of opposite ridges. Thus, the heat transfer fluids may be even more efficiently directed under and over the joints or contact points of adjacent heat exchanger plates resulting in a further increased performance in terms of heat transfer.
[0035] The protrusions may be offset with respect to the ridges along the protrusion line with half of the uniform pitch, which is advantageous in that a uniform distribution of the heat transfer fluids may be achieved. In practice, the heat transfer fluids may be even more efficiently directed to the valley regions in between each pair of opposite ridges. Thus, the heat transfer fluids may be even more efficiently directed under and over the joints or contact points of adjacent heat exchanger plates resulting in a further increased performance in terms of heat transfer.
[0036] The second height may correspond to 30% to 90%, such as 75% to 90%, of the first height which is advantageous in that the protrusions may efficiently act as a flow disturbance for the heat transfer fluids. In other words, the protrusions may cause a significant turbulence increasing the overall performance of the heat exchanger in terms of heat transfer.
[0037] The second height may correspond to substantially 83% of the first height. The first height may be substantially 1 ,8 mm.
[0038] The second height may be substantially 1,5 mm.
[0039] The first and the second ridge lines and the protrusion line may extend at an oblique angle in a range of 30 degrees to 60 degrees, such as 40 degrees to 50 degrees, with respect to a longitudinal axis of the first and second heat exchanger plates, which is advantageous in that the performance in terms of heat transfer may be further increased. In practice, by the first and the second ridge lines and the protrusion line extending at an oblique angle in a range of 30 degrees to 60 degrees, such as 40 degrees to 50 degrees, with respect to a longitudinal axis of the first and second heat exchanger plates, a favorable balance between heat transfer and pressure drop may be achieved.
[0040] The ridges may be arranged one after the other along a plurality of ridge lines, the plurality of ridge lines extending in parallel to each other and to the horizontal extension plane, which is advantageous in that the heat transfer pattern may be provided to cover an area of an arbitrary size. In other words, the heat transfer pattern may be provided to cover an area of any size and shape.
[0041] The ridges may be arranged one after the other along a plurality of ridge lines.
[0042] The plurality of ridge lines may extend in parallel to each other and to the horizontal extension plane.
[0043] The protrusions may be arranged one after the other along a plurality of protrusion lines, each extending in between a pair of adjacent ridge lines, and being parallel to the ridge lines and to the horizontal extension plane, which is advantageous in that the heat transfer pattern may be provided to cover an area of an arbitrary size. In other words, the heat transfer pattern may be provided to cover an area of any size and shape.
[0044] Each protrusion line may extend in between a pair of adjacent ridge lines.
[0045] Each protrusion line may be parallel to the ridge lines.
[0046] Each protrusion line may be parallel to the to the horizontal extension plane.
[0047] Each first and second exchanger plate may comprise a pair of first port holes and a pair of second port holes extending therethrough, the first port holes being configured to receive and eject a first fluid and the second port holes being configured to receive and eject a second fluid.
[0048] The first heat exchanger plates and second heat exchanger plates may be of a corresponding type, and wherein the second heat exchanger plates are rotated 180 degrees in parallel with the horizontal extension plane, which is advantageous in that a single type of heat exchanger plate may be fabricated and used as both first heat exchanger plates and second heat exchanger plates. In other words, a single type of heat exchanger plate may be used as both first heat exchanger plates and second heat exchanger plates by rotating every second heat exchanger plate 180 degrees in parallel with the horizontal extension plane.
[0049] According to another aspect of the invention, there is provided a plate heat exchanger comprising: a heat exchanger core according to the first aspect, a first end plate provided at a first end of the heat exchanger core as seen along the vertical direction, and a second end plate provided at a second end of the heat exchanger core as seen along the vertical direction.
[0050] In general, features of this aspect provide similar advantages as discussed above in relation to the first aspect. Consequently, said advantages will not be repeated in order to avoid undue repetition.
[0051] It should be noted that within the context of this application the term “end plate” is here meant a plate of the heat exchanger that is void of a heat exchange area. Further, an end plate may be formed of a series of sub-plates stacked on top of each other. Such sub-plates may be of the same type or may for instance have different thicknesses or may be formed of different materials.
[0052] One end plate of the first end plate and the second end plate, may comprise a first opening in fluid communication with a first port hole, and wherein one end plate of the first end plate and the second end plate, may comprise a second opening in fluid communication with a second port hole.
[0053] By the above design the first end plate may comprise zero or more openings. Correspondingly, the second end plate may comprise zero or more openings.
[0054] The plate heat exchanger may comprise a pair of first openings in fluid communication with a respective first port hole of the pair of first port holes of the heat exchanger core.
[0055] The plate heat exchanger may comprise a pair of second openings in fluid communication with a respective second port hole of the pair of second port holes of the heat exchanger core.
[0056] In practice, the plate heat exchanger may comprise a pair of first openings in fluid communication with a respective first port hole of the pair of first port holes of the heat exchanger core, and a pair of second openings in fluid communication with a respective second port hole of the pair of second port holes of the heat exchanger core. In this case, the first openings and the second openings may be arbitrary distributed between the first end plate and the second end plate. That is, zero or more of the first openings and the second openings may be provided at the first end plate. Correspondingly, zero or more of the first openings and the second openings may be provided at the second end plate. Thus, four openings out of four may be provided at the first end plate or at the second end plate. Three openings out of four may be provided at the first end plate or at the second end plate, meaning that one opening may be provided at the other one of the first end plate and the second end plate. Two openings out of four may be provided at the first end plate or at the second end plate, meaning that two openings may be provided at the other one of the first end plate and the second end plate. Both first openings may be provided at the fist end plate and both second openings may be provided at the second end plate.
[0057] A further scope of applicability of the present invention will become apparent from the detailed description given below. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the scope of the invention will become apparent to those skilled in the art from this detailed description.
[0058] Hence, it is to be understood that this invention is not limited to the particular component parts of the device described as such device may vary. It is also to be understood that the terminology used herein is for purpose of describing particular embodiments only and is not intended to be limiting. It must be noted that, as used in the specification and the appended claim, the articles "a," "an," "the," and "said" are intended to mean that there are one or more of the elements unless the context clearly dictates otherwise. Thus, for example, reference to "a unit" or "the unit" may include several devices, and the like. Furthermore, the words "comprising", "including", "containing" and similar wordings does not exclude other elements or steps.
[0059] Brief of the
[0060] The above and other aspects of the present inventive concept will now be described in more detail, with reference to appended figures. The figures should not be considered limiting, instead, they are used for explaining and understanding.
[0061] As illustrated in the figures, the sizes of layers and regions may be exaggerated for illustrative purposes and, thus, are provided to illustrate the general structures of variants. Like reference numerals refer to like elements throughout.
[0062] Fig. 1A is a schematic exemplary side view of a plate heat exchanger. Fig. 1B is an exemplary schematic cross sectional top view of the plate heat exchanger of Fig. 1A.
[0063] Fig. 2A is a top view of a heat exchanger plate provided with a heat transfer pattern in a heat exchange area thereof.
[0064] Fig. 2B is an enlarged view of the heat transfer pattern of Fig. 2A.
[0065] Fig. 3A is a cross-sectional perspective view of a first heat exchanger plate and a second heat exchanger plate joined to each other.
[0066] Fig. 3B is a cross-sectional view of the first heat exchanger and a second heat exchanger plate of Fig. 3A.
[0067] Detailed Description
[0068] The present inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred variants or embodiments of the inventive concept are shown. This inventive concept may, however, be implemented in many different forms and should not be construed as limited to the variants set forth herein; rather, these variants are provided for thoroughness and completeness, and fully convey the scope of the present inventive concept to the skilled person.
[0069] Example embodiments of a heat exchanger core 10 and a plate heat exchanger 1 will in the below be described with reference to the drawings. The drawings are only schematic and the relative dimensions of some structures and layers may be exaggerated and not drawn to scale. Rather the dimensions may be adapted for illustrational clarity and to facilitate understanding. When present in the figures, the indicated axis H and V consistently refer to a horizontal or lateral direction H of the plate heat exchanger 1 and vertical direction V of the plate heat exchanger 1. The term “horizontal” direction H refers to any directions parallel to an extension plane P of the heat exchanger plates of the plate heat exchanger 1. The term “vertical” direction V refers to a direction parallel to a normal direction of the extension plane P of the heat exchanger plates of the plate heat exchanger 1. Further, the (positive) vertical direction refers to a direction which points out of what typically is regarded a lower end plate 402 of the plate heat exchanger 1. This means that fluid entering and exiting the plate heat exchanger 10 through ports thereof, in the depicted embodiments enters and exits the plate heat exchanger 1 in negative vertical direction, i.e. , a direction which is opposite to the vertical direction. However, according to embodiments, fluid may enter or exit the plate heat exchanger 1 in the positive vertical direction and / or in the negative vertical direction. Now turning to Figs. 1A and 1 B. Fig. 1A and 1 B schematically illustrate by way of example an exemplary plate heat exchanger 1. The plate heat exchanger 1 includes a heat exchanger core 10, which is formed by a number of heat exchanger plates 100, 200. The heat exchanger core 10 or core 10 may commonly also be referred to as a plate package. The heat exchanger plates 100, 200 forming the core 10 are typically formed from sheet metal which is cut to size and pressed to the shape of the heat exchanger plates 100, 200. The heat exchanger plates 100, 200 are stacked on top of each other in a stacking direction. In the depicted core 10 of the plate heat exchanger 1 , the heat exchanger plates 100, 200 are stacked in the vertical direction V. The core 10 of the plate heat exchanger 1 comprises two different types of heat exchanger plates, which in the following when deemed appropriates are referred to as first heat exchanger plates 100 and as second heat exchanger plate 200. Correspondingly, a first heat exchanger plate 100 or a second heat exchanger plate 200 will be referred to as a heat exchanger plate 100, 200 whenever deemed appropriate.
[0070] The core 10 includes substantially the same number of first heat exchanger plates 100 and second heat exchanger plates 200. As is clear from Fig. 1A, the heat exchanger plates 100, 200 are provided on top of each other in such a way that a first plate interspace 11 is formed between each pair of adjacent first and second heat exchanger plates 100, 200, and a second plate interspace I2 is formed between each pair of adjacent second and first heat exchanger plates 200, 100.
[0071] Every second plate interspace thus forms a respective first plate interspace 11 and the remaining plate interspaces form a respective second plate interspace I2, i.e. , the first and second plate interspaces 11 , I2 are provided in an alternating order in the core 10 of the plate heat exchanger 10. Furthermore, the first and second plate interspaces 11 , I2 are separated from each other. The first plate interspaces 11 are configured to receive a first heat transfer fluid or first fluid, and second plate interspaces I2 configured to receive a second heat transfer fluid or second fluid.
[0072] According to a non-limiting example, the plate heat exchanger 1 may be configured to operate as an evaporator in a cooling agent circuit, not disclosed. In such an evaporator application, the first plate interspaces 11 may form first passages for the first fluid being a refrigerant whereas the second plate interspaces I2 may form second passages for a second fluid, which is to be cooled by the first fluid.
[0073] According to a non-limiting example, the plate heat exchanger 1 may also be reversed, and is then configured to be operated as a condenser, wherein the first fluid, i.e. the refrigerant, is condensed in the first plate interspaces 11 , and the second fluid is conveyed through the second plate interspaces I2 for cooling the first fluid conveyed through the first plate interspaces 11.
[0074] The depicted plate heat exchanger 1 of Fig. 1A and 1 B includes a first end plate 400 in the form of an upper end plate 400, and a second end plate 402 in the form of a lower end plate 402. The first end plate 400 and the second end plate 402 are provided on a respective side of the core 10 of the plate heat exchanger 1. Thus, the first end plate 400 is provided at a first end of the heat exchanger core 10 as seen along the vertical direction V, and the second end plate 402 provided at a second end of the heat exchanger core 10 as seen along the vertical direction V of the depicted plate heat exchanger 1 of Figs. 1A and 1B.
[0075] In the core 10 of the depicted heat exchanger 1 the heat exchanger plates 100, 200 may be permanently joined to each other. Further, the heat exchanger plates 100, 200 and the end plates 400, 402 may be permanently joined to each other. Such a permanent joining may advantageously be performed through brazing, welding, by use of an adhesive and / or bonding. During joining by means of brazing a suitable number of heat exchanger plates 100 are typically stacked on top each other with a solder or braze material, such as copper or a copper alloy, located between adjacent heat exchanger plates 100, 200, at desired locations, typically where joints are to be formed. The first and second heat exchanger plates 100, 200 may to advantage be made of a metal or a metal alloy, such as stainless steel, which extends to the outer surface of the heat exchanger plates 100, 200. The outer surface of the metal or metal alloy typically has such properties that it adheres to the solder or braze material during the brazing of the plate heat exchanger 1. During such brazing the whole core 10 of the plate heat exchanger 10 is heated in an oven until said solder or braze material melts. This will result in a permanent joint between the heat exchanger plates 100, 200 of core of the plate heat exchanger 10.
[0076] Alternatively, during joining by means of brazing a suitable number of heat exchanger plates 100, 200 are typically stacked on top each other with a melting point depressant located between adjacent heat exchanger plates 100, 200 at desired locations, typically where joints are to be formed. The first and second heat exchanger plates 100, 200 may to advantage be made of a metal or a metal alloy, such as stainless steel, which extends to the outer surface of the heat exchanger plates 100, 200. The outer surface of the metal or metal alloy typically has such properties that it adheres to adjacent heat exchanger plates during brazing of the plate heat exchanger 10 when using a melting point depressant. During such brazing the whole core 10 of the plate heat exchanger 1 is heated in an oven until the material of the heat exchanger plates 100, 200 locally melts at the locations of the melting point depressant. This will result in a permanent joint between the heat exchanger plates 100, 200 of core 10 of the plate heat exchanger 1.
[0077] As schematically depicted in Fig. 1 B, the first top plate 400 of the depicted plate heat exchanger 1 has four portholes 170, 180.
[0078] Now also turning to Fig. 2A. Fig. 2A schematically illustrates a heat exchanger plate 100, 200 of the core 10 of the plate heat exchanger 1 of Figs 1A and 1 B. The depicted heat exchanger plate 100, 200 of Fig. 2A is designed such that it may function as a first heat exchanger plate 100 or a second heat exchanger plate 200 by rotating the heat exchanger plate 100, 200 180 degrees in parallel with the horizontal H extension plane P.
[0079] As depicted in Fig. 2A, the heat exchanger plate 100, 200 comprises a pair of first port holes 150 and a pair of second port holes 160 extending therethrough. The first port holes 150 are in fluid communication with the first openings 170 provided in the first end plate 400, as schematically illustrated in Fig. 1 B. Moreover, the fist port holes 150 are configured to receive and eject a first fluid or first heat transfer fluid as is known in the art.
[0080] Correspondingly, the second port holes 160 are in fluid communication with the second openings 180 provided in the first end plate 400, as schematically illustrated in Fig. 1 B. Moreover, the second port holes 160 are configured to receive and eject a second fluid or second heat transfer fluid as is known in the art.
[0081] The heat exchanger plate 100, 200 of Fig, 2A comprises a heat exchange area A. The heat exchange area A is configured to transfer heat between a first fluid present in a first plate interspace 11 and a second fluid present in a second plate interspace I2 as is known in the art.
[0082] Further, the heat exchanger plate 100, 200 of Fig, 2A comprises a fluid distribution area DA in proximity to each port hole 150, 160.
[0083] The fluid distribution areas DA in proximity to the first port holes 150 serves the general purpose of distributing and collecting a first heat transfer fluid to and from the first plate interspaces 11. Thus, the fluid distribution areas DA in proximity to the first port holes 150 are configured to distribute the first heat transfer fluid to the heat exchange areas A of every second pair of adjoining heat exchanger plates 100, 200, and to collect the first heat transfer fluid from said heat exchange areas A.
[0084] Correspondingly, the fluid distribution areas DA in proximity to the second port holes 160 serves the general purpose of distributing and collecting a second heat transfer fluid to and from the second plate interspaces I2. Thus, the fluid distribution areas DA in proximity to the second port holes 160 are configured to distribute the second heat transfer fluid to the heat exchange areas A of the other pairs of adjoining heat exchanger plates 200, 100, and to collect the second heat transfer fluid from said heat exchange areas A.
[0085] As illustrated in Fig. 2A, each fluid distribution area DA includes a plurality of more or less elongated crests or ridges 152. The crests 152 extend in a respective substantially radial direction R of their associated port hole 150, 160. The hatched line indicated by R in Fig. 2A illustrates one radial direction by way of example. By the illustrated configuration of the fluid distribution areas DA, crests 152 of overlapping fluid distribution areas DA of adjoining heat exchanger plates 100, 200 will extend, generally speaking, in different radial directions, such that more or less elongated joining areas 154 are formed in between consecutive crests 152. In this way an improved strength as well as an improved fluid distribution may be achieved in the fluid distribution areas DA of the core 10 and hence in the complete plate heat exchanger 1.
[0086] The heat exchange area A of the depicted heat exchanger plate 100, 200 is provided with a heat transfer pattern 300. In the following, the design of the heat transfer pattern 300 will be described in grater detail while also referring to Figs. 2B, 3A and 3B. It will also be described how the heat transfer pattern 300 promotes an increased overall strength as well as an increased performance of the core 10 and hence of the entire plate heat exchanger 1. When doing so, reference is made to a pair of a first heat exchanger plate 100 and an adjoining second heat exchanger plate 200. Further, it is assumed that both the first heat exchanger plate 100 and an adjoining second heat exchanger plate 200 are provided with a heat transfer pattern 300 of the depicted type. Thus, each of one of a first heat exchanger plate 100 and an adjoining second heat exchanger plate 200 comprises a heat exchange area A provided with the heat transfer pattern 300. It is also assumed that the first and second heat exchanger plates 100, 200 are of the type depicted in Fig. 2A and that the second heat exchanger plate 200 is rotated 180 degrees in parallel with the horizontal extension plane P with respect to the first heat exchanger plate 100 such that the heat transfer pattern 300 of the first and second heat exchanger plates 100, 200 becomes staggered, as will be explained below.
[0087] Now turning also to Figs. 2B, 3A and 3B. Fig. 2B illustrates an enlarged detail view of the heat transfer pattern 300 of the heat exchanger plate 100, 200 of Fig. 2A. Figs. 3A and 3B illustrates a how a pair of heat exchanger plates 100, 200 are stacked onto each other and joined to each other. To this end, Figs. 3A and 3B illustrates a single pair of adjoining heat exchanger plates 100, 200 for reasons of legibility. It is however to be understood that a multitude of heat exchanger plates 100, 200 are typically stacked onto each other and joined to each other in a core 10 of a plate heat exchanger 1.
[0088] The heat transfer pattern comprises ridges 310 and protrusions 320. As best illustrated in Fig. 2B, a plurality of the ridges 310 are arranged one after the other along a first ridge line 312a. Correspondingly, a plurality of the ridges 310 are arranged one after the other along a second ridge line 312b.
[0089] The ridges 310 of the first ridge line 312a are arranged opposite to ridges 310 of the second ridge line 312b. In the depicted heat transfer pattern 300 of Fig. 2B, the ridges 310 of the first ridge line 312a are arranged directly opposite to ridges 310 of the second ridge line 312b. In this way, a respective valley region 330 is formed in between each pair of opposite ridges 310. It is however to be understood that the ridges 310 of the first ridge line 312a may be arranged partially opposite to ridges 310 of the second ridge line 312b. In other words, the ridges 310 of the first ridge line 312a and the ridges 310 of the second ridge line 312b may be arranged in a overlapped fashion.
[0090] Further, the first and the second ridge lines 312a, 312b are extending in parallel to each other and to the horizontal extension plane P, see Fig. 2A.
[0091] A plurality of the protrusions 320 are arranged one after the other along a protrusion line 320a. The protrusion line 320a of the depicted heat transfer pattern 300 of Fig. 2B extends in between the first and second ridge lines 312a, 312b. Further, the protrusion line 320a is parallel to the first and second ridge lines 312a, 312b and to the horizontal extension plane P.
[0092] Further, as best illustrated in Fig. 2B, the protrusions 320 are offset with respect to the ridges 310 along the protrusion line 320a.
[0093] Further, as best illustrated in Fig. 2B, the ridges 310 are arranged at a uniform pitch along the first and second ridge lines 312a, 312b. It is however conceivable to arrange the ridges 310 at a non-uniform pitch along the first and second ridge lines 312a, 312b. For instance, such a non-uniform pitch may vary along the first and second ridge lines 312a, 312b.
[0094] Further, as best illustrated in Fig. 2B, the protrusions 320 are arranged at the uniform pitch along the protrusion line 320a. Thus, in the depicted heat transfer pattern 300, the ridges 310 and the protrusions 320 are arranged at the very same pitch. Moreover, as best illustrated in Fig. 2B, the protrusions 320 are offset with respect to the ridges 310 along the protrusion line 320a with half of the uniform pitch.
[0095] It is, however, conceivable to arrange the ridges 310 and the protrusions 320 at different pitches. Moreover, it is conceivable to arrange protrusions 320 at a non- uniform pitch along the protrusion line 320a. For instance, such a pitch may vary along the protrusion line 320a. Likewise, it is conceivable to offset the protrusions 320 with respect to the ridges 310 along the protrusion line 320a with another value than half of the uniform pitch. Thus, as is understood from the above, a multitude of different configurations of the ridges 310 and the protrusions 320 are conceivable.
[0096] Further, as best illustrated in Fig. 2B, the ridges 310 are arranged one after the other along a plurality of ridge lines 312a, 312b, 312x, and not just along the first ridge line 312a and the second ridge line 312b. The plurality of ridge lines 312a, 312b, 312x extend in parallel to each other and to the horizontal extension plane P.
[0097] Correspondingly, as best illustrated in Fig. 2B, the protrusions 320 are arranged one after the other along a plurality of protrusion lines 320a, 320x, and not just along the protrusion line 320a. The plurality of protrusion lines 320a, 320x each extend in between a pair of adjacent ridge lines 312a, 312b, 312x, and is parallel to the ridge lines 312a, 312b, 312x and to the horizontal extension plane P.
[0098] As best illustrated in Figs. 3A and 3B, the upper heat exchanger plate 200 is joined to the lower heat exchanger plate 100 of the illustrated pair of heat exchanger plates 100, 200. In other words, a first heat exchanger plate 100 is joined to a second heat exchanger plate 200 in Figs 3A and 3B. The first heat exchanger plate 100 is joined to the second heat exchanger plate 200 by joints 350. The joints 350 of the depicted heat exchanger plates of Figs. 3A and 3B are formed by brazing, the general principles of which has been described above. More specifically, each joint 350 is formed at an interface between a respective ridge 310 of the first heat exchanger plate 100 and a respective valley region 330 of the second heat exchanger plate 200, as best illustrated in Fig, 3B. In this way, each joint 350 will have an elongated shape along its associated valley region 330, i.e. in direction parallel to the ridge lines 312a, 312b, 312x. Such elongated shape of the joints 350 results in an increased strength of the core 10 as compared to state of the art cores in which fishbone patterns are used. In such state of the art fishbone patterns joints are formed locally at locations where pattern features of adjoining heat exchanger plates cross each other, thus resulting in more or less point shaped joints. It is to be noted that the reference numerals 310, 320, 330 in Fig. 3A refer to the upper heat exchanger plate 200 of Fig. 3A for reasons of legibility.
[0099] In Fig. 3B, a portion of a profile or height profile of the lower or first heat exchanger plate 100 is schematically illustrated below the actual illustration of the heat exchanger plates 100, 200. More specifically, a portion of the profile of the first heat exchanger plate 100 between the two vertically extending dashed lines is schematically illustrated below the actual illustration of the heat exchanger plates 100, 200. The illustrated portion of the profile includes, for illustrative purposes, two ridges 310 and a protrusion 320 located between the ridges 310. As clearly illustrated the ridges 310 protrude a first height H1 in the vertical direction V, and protrusions 320 protrude a second height H2 in the vertical direction V. Further, as clearly illustrated, the first height H1 is greater than the second height H2e. Since the joints 350 are formed at the locations of the ridges 310 having the first height H1 which is greater than the second height H2 of the protrusions 320, the protrusions 320 of the first heat exchanger plate 100 will not come into contact with the second heat exchanger plate 200. As a result, a space is formed along each protrusion line 320a, 320x of the core 10. In this way, the heat transfer fluids may efficiently be directed to the valley regions 330 in between each pair of opposite ridges 330 of the associated heat exchanger plate 100, 200. That is, the heat transfer fluids may efficiently be directed under and over the joints 350 or contact points of adjacent heat exchanger plates 100, 200. Further, in this way the flow disturbance and hence the turbulence in the heat transfer fluids may be increased which results in a more efficient heat transfer. Furthermore, in this way, the total area efficiently contributing to the heat transfer between the heat transfer fluids may be increased. In other words, the total effective heat transfer area A may be increased.
[0100] After significant experimentation it has been found that when the second height H2, i.e. the height of the protrusions 320, corresponds to 30% to 90%, of the first height H1, i.e. the height of the ridges 310, particularly favorable conditions may be achieved. In this regards, particularly favorable conditions in terms of providing turbulence, increasing heat transfer and distributing heat a transfer fluid may be achieved when the second height H2 corresponds to 30% to 90%, of the first height H1. It is currently believed that when the second height H2, corresponds to 75% to 90% of the first height H1, an optimal balance between providing turbulence, increasing heat transfer, distributing a heat transfer fluid and pressure drop may be achieved. According to an example, the first height H1 may be 1,8 mm and the second height H2 may be 1,5 mm. Thus, the second height H2 may correspond to approximately 83% of the first height H1.
[0101] In the depicted heat transfer pattern 300, and as depicted in Fig. 2B, a respective further valley region 335 is formed in between consecutive ridges 310 of the plurality of ridge lines 312a, 312b, 312x. Hence, a respective further valley region 335 is formed in between consecutive ridges 310 of the first and second ridge lines 312a, 312b. The further valley regions 335 are, each extending along an associated ridge line 312a, 312b, 312x of the plurality of ridge lines 312a, 312b, 312x. However, each further valley region 335 has a shorter extension along its associated ridge line 312a, 312b, 312x as compared to the extension of each valley region 330 along its associated protrusion line 320a, 320x.
[0102] As illustrated in Fig. 3B, the valley regions 330 and the further valley regions 335 may be arranged in a common valley plane VP being parallel to the horizontal extension plane P. By this arrangement of the valley regions 330 and the further valley regions 335, the surface area of the heat transfer pattern 300 may efficiently be increased or maximized. This because the material of the heat exchanger plate 100, 200 may be additionally stretched at the location of the heat transfer pattern 300 as compared to if, for instance, the further valley regions 335 were to be located at a level above the common valley plane. Such additional stretching of the material of the heat exchanger plate 100, 200 will for natural reasons result in an overall increased surface area of the heat transfer pattern 300.
[0103] After significant experimentation it has been found that when a length extension L of each ridge 310 along its associated ridge line 312a, 312b, 312x corresponds to at least 2 times of a width extension W of the ridge 310 transverse the associated ridge line 312a, 312b, 312x, particularly favorable conditions may be achieved. The length extension L and the width extension W of a ridge 310 is schematically illustrated in Fig. 2B. In this regards, particularly favorable conditions in terms of strength and increased heat transfer may be achieved when the length extension L of each ridge 310 corresponds to at least 2 times of the width extension W. It is currently believed that when the length extension L of each ridge 310 corresponds to at least 1,5 to 5 times of the width extension W, an optimal balance between strength, heat transfer, and pressure drop may be achieved.
[0104] As best illustrated in Fig. 2B, the ridge lines 312a, 312b, 312x and the protrusion lines 320a, 320x may typically extend at an oblique angle a with respect to a longitudinal axis LA of the exchanger plates 100, 200. After significant experimentation it has been found that when the ridge lines 312a, 312b, 312x and the protrusion lines 320a, 320x extends at an oblique angle a, in a range of 30 degrees to 60 degrees with respect to the longitudinal axis LA of the heat exchanger plates 100, 200, particularly favorable conditions may be achieved in terms of pressure drop and heat transfer. It is currently believed that when the when the ridge lines 312a, 312b, 312x and the protrusion lines 320a, 320x extends at an oblique angle a, in a range of 40 degrees to 50 degrees, such as 45 degrees, with respect to the longitudinal axis LA of the heat exchanger plates 100, 200 an optimal balance between pressure drop, heat transfer and distribution of the heat transfer fluids may be achieved. In this regard, a reduced oblique angle a will result in a lower pressure drop but will at the same time reduce the heat transfer. On the other hand, an increased oblique angle a will lead to an increased pressure drop but will at the same time enhance the heat transfer. However, if the oblique angle a becomes too large, the pressure drop will increase to a level where the flows of the heat transfer fluids are significantly inhibited potentially resulting in a decreased heat transfer.
[0105] It will be appreciated that the present inventive concept is not limited to the variants and examples shown. Several modifications and variations are thus conceivable within the scope of the invention which thus is defined by the appended claims.
Claims
CLAIMS1. A heat exchanger core (10) for a plate heat exchanger (1) comprising: first heat exchanger plates (100) and second heat exchanger plates (200) alternatingly stacked onto each other in a vertical direction (V), and extending in parallel to a horizontal (H) extension plane (P), wherein each of one of a first heat exchanger plate (100) and an adjoining second heat exchanger plate (200) comprises a heat exchange area (A) provided with a heat transfer pattern (300), wherein the heat transfer pattern comprises ridges (310) protruding a first height (H1) in the vertical direction (V), and protrusions (320) protruding a second height (H2), in the vertical direction (V), wherein the ridges (310) are arranged one after the other along a first ridge line (312a) and a second ridge line (312b), wherein ridges (310) of the first ridge line (312a) are arranged to opposite ridges (310) of the second ridge line (312b), thereby forming a respective valley region (330) in between each pair of opposite ridges (310), the first and the second ridge lines (312a, 312b) extending in parallel to each other and to the horizontal (H) extension plane (P), wherein the protrusions (320) are arranged one after the other along a protrusion line (320a), extending in between the first and second ridge lines (312a, 312b), and being parallel to the first and second ridge lines (312a, 312b) and to the horizontal (H) extension plane (P), wherein the protrusions (320) are offset with respect to the ridges (310) along the protrusion line (320a), and wherein the first height (H1) is greater than the second height (H2) such that a space is formed along the protrusion line (320a), characterized in that the first heat exchanger plate (100) is joined to the second heat exchanger plate (200) by joints (350), each joint (350) being formed at an interface between a respective ridge (310) of the first heat exchanger plate (100) and a respective valley region (330) of the second heat exchanger plate (200).
2. The heat exchanger core (10) according to claim 1, wherein a respective further valley region (335) is formed in between consecutive ridges (310) of the first and second ridge lines (312a, 312b).
3. The heat exchanger core (10) according to claim 2, wherein the valley regions (330) and the further valley regions (335) are arranged in a common valley plane (VP) being parallel to the horizontal (H) extension plane (P).
4. The heat exchanger core (10) according to any one of the preceding claims, wherein a length extension (L) of each ridge (310) along the associated first or second ridge line (312a, 312b) corresponds to at least 2 times, such as at least 1 ,5 to 5 times, of a width extension (W) of the ridge (310) transverse the associated first or second ridge line (312a, 312b).
5. The heat exchanger core (10) according to any one of the preceding claims, wherein ridges (310) of the first ridge line (312a) are arranged directly opposite ridges (310) of the second ridge line (312b).
6. The heat exchanger core (10) according to any one of the preceding claims, wherein the ridges (310) are arranged at a uniform pitch along the first and second ridge lines (312a, 312b).
7. The heat exchanger core (10) according to claim 6, wherein the protrusions (320) are arranged at the uniform pitch along the protrusion line (320a).
8. The heat exchanger core (10) according to claim 6 or 7, wherein the protrusions (320) are offset with respect to the ridges (310) along the protrusion line (320a) with half of the uniform pitch.
9. The heat exchanger core (10) according to any one of the preceding claims, wherein the second height (H2) corresponds to 30% to 90%, such as 75% to 90%, of the first height (H1e).
10. The heat exchanger core (10) according to any one of the preceding claims, wherein the first and the second ridge lines (312a, 312b) and the protrusion line (320a) extend at an oblique angle (a) in a range of 30 degrees to 60 degrees, such as 40 degrees to 50 degrees, with respect to a longitudinal axis (LA) of the first and second heat exchanger plates (100, 200).
11. The heat exchanger core (10) according to any one of the preceding claims, wherein the ridges (310) are arranged one after the other along a plurality of ridge lines (312a, 312b, 312x), the plurality of ridge lines (312a, 312b, 312x) extending in parallel to each other and to the horizontal (H) extension plane (P).
12. The heat exchanger core (10) according to claim 11, wherein the protrusions (320) are arranged one after the other along a plurality of protrusion lines (320a, 320x), each extending in between a pair of adjacent ridge lines (312a, 312b,312x), and being parallel to the ridge lines (312a, 312b, 312x) and to the horizontal (H) extension plane (P).
13. The heat exchanger core (10) according to any one of the preceding claims, wherein each first and second exchanger plate (100, 200) comprises a pair of first port holes (150) and a pair of second port holes (160) extending therethrough, the first port holes (150) being configured to receive and eject a first fluid and the second port holes (160) being configured to receive and eject a second fluid.
14. The heat exchanger core (10) according to any one of the preceding claims, wherein the first heat exchanger plates (100) and second heat exchanger plates (200) are of a corresponding type, and wherein the second heat exchanger plates (200) are rotated 180 degrees in parallel with the horizontal (H) extension plane (P).
15. A plate heat exchanger (1) comprising: a heat exchanger core (10) according to any one of the preceding claims, a first end plate (400) provided at a first end of the heat exchanger core (10) as seen along the vertical direction (V), and a second end plate (402) provided at a second end of the heat exchanger core (10) as seen along the vertical direction (V).
16. The plate heat exchanger (1) according to claim 15, when dependent on claim 13, wherein one end plate (400, 402) of the first end plate (400) and the second end plate (402), comprises a first opening (170) in fluid communication with a first port hole (150), and wherein one end plate (400, 402) of the first end plate (400) and the second end plate (402), comprises a second opening (180) in fluid communication with a second port hole (160).