Printed circuit heat exchanger

Abstract

The present invention relates to a printed circuit heat exchanger (1) comprising: a heat exchanger core (10), a first end plate (50), and a second end plate (60). The heat exchanger core (10) comprises first heat exchanger plates (100) and second heat exchanger plates (200) alternatingly stacked onto each other in a stacking direction (S), and joined to each other. The heat exchanger core (10) is arranged between the first end plate (50) and the second end plate (60). Each first heat exchanger plate (100) comprises a first heat exchange area (A1) comprising a number of first grooves (102) forming a respective first passage (104) for a first media, the first passage (104) extending between a first inlet (104:1), and a first outlet (104:2). Each second heat exchanger plate (200) comprises a second heat exchange area (A2) comprising a number of second grooves (202), forming a respective second passage (204) for a second media, the second passage (204) extending between a second inlet (204:1), and a second outlet (204:2). The printed circuit heat exchanger (1) is provided with one or more dummy holes (500) configured to reduce a thermal mass of the printed circuit heat exchanger (1), wherein each dummy (500) hole is provided in the first end plate (50), the second end plate (60), a first heat exchanger plate (100) or a second heat exchanger plate (200), and wherein each dummy hole (500) is disconnected from the first grooves (102) and the second grooves (202).

Description

[0001] PRINTED CIRCUIT HEAT EXCHANGER

[0002] Technical Field

[0003] The invention relates to the field of heat exchangers. More particularly, it is related to a printed circuit heat exchanger.

[0004] The printed circuit heat exchanger has a heat exchanger core having first heat exchanger plates and second heat exchanger plates alternatingly stacked onto each other in a stacking direction and joined to each other. Each first heat exchanger plate has a first heat exchange area having a number of passages for a first media, and each second heat exchanger plate has heat exchange area having a number of passages for a second media.

[0005] Background Art

[0006] Plate heat exchangers are used in numerous applications where heat is to be transferred from one fluid to another or vice versa. A typical plate heat exchanger includes a plate package or core formed of stacked heat exchanger plates.

[0007] One type of plate heat exchanger is the so-called printed circuit heat exchanger (PCHE). A PCHE generally has a core of a number of first heat exchanger plates and a number of second heat exchanger plates. The heat exchanger plates are typically stacked in an alternating fashion and joined to each other. Each fist heat exchanger plate generally has a heat exchange area which includes a number of passages formed by grooves which are etched into the material of the heat exchanger plate. Correspondingly, each second heat exchanger plate generally has a heat exchange area which includes a number of passages formed by grooves which are etched into the material of the heat exchanger plate. The core is typically arranged between a pair of end plates, thereby forming the PCHE.

[0008] The first heat exchanger plates and the second heat exchanger plates of a PCHE are typically joined to each other by a diffusion bonding process. Correspondingly, the end plates of a PCHE are typically joined to the core by a diffusion bonding process. In this way a strong bond is established between the respective plates of the PCHE. When heat exchanger plates are diffusion bonded to each other, a solid heat exchanger core with tailor made passages can be formed. Given the strong bond between the heat exchanger plates and the end plates, a PCHE is generally suitable for high pressure applications where the PCHE is subjected to high working pressures which would risk breaking a common state of the art plate heat exchanger with e.g. press or punch shaped heat exchanger plates. PCHEs are commonly used in hydrogen refueling stations due to the sturdy and pressure resistant nature of PCHEs. Although PCHEs have excellent resistance to high pressures, problems related to material fatigue can in practice significantly limit the lifetime of a PCHE. For instance, when a PCHE is used in a hydrogen refueling station, the PCHE will be subjected to great repeated cyclic temperature variations while at the same time being subjected to high pressures. Such great repeated cyclic temperature variations in combination with the high pressure can result in premature material fatigue with material rupture as a result. Such material fatigue may typically occur at locations of the PCHE where more dense areas meet less dense areas. For instance, at a location where an area with a significant amount of solid material meets an area with a significant number of grooves thermal stress may build up when the temperature of the PCHE changes.

[0009] It has been suggested to design heat exchanger cores of PCHEs in a way where thermally induced material stresses are reduced. To this end, it has been suggested to provide slits extending vertically, completely or partially, through the heat exchanger. Although this approach can locally reduce thermally induced material stresses it typically complicates the overall design of the heat exchanger core and reduces its performance.

[0010] The presence of a slit in a heat exchanger plate or end plate will for natural reasons limit the design freedom and potentially hamper the extension of the heat exchange area. The design can be even more hampered when the PCHE at hand is to include port holes and port openings for providing media to the respective heat exchange areas. In practice, the port holes, and port openings will compete with the slits for the valuable area available on the heat exchanger plates and the end plates. This means in practice that the presence of such slits will lower the performance of the PCHE since the slits will occupy an area which otherwise could have been used to exchange heat. Further, the introduction of such slits will typically complicate the fabrication of the PCHE and can require further manufacturing steps.

[0011] Hence, there is room for improvement when it comes to reducing thermally induced stresses in PCHEs.

[0012] Summary

[0013] With the above in mind, it is an object of the present invention to provide an improved printed circuit heat exchanger. Another object is to provide such a printed circuit heat exchanger which is capable of handling great cyclic temperature variations with a reduced risk of breaking or otherwise failing.

[0014] Another object is to provide such a printed circuit heat exchanger which is capable of handling larger temperature differences between the media used in a heat exchange process.

[0015] Another object is to provide such a printed circuit heat exchanger which has a prolonged lifetime.

[0016] Another object is to provide such a printed circuit heat exchanger which has an improved overall performance.

[0017] Another object is to provide such a printed circuit heat exchanger which is less prone to cracking.

[0018] Another object is to provide such a printed circuit heat exchanger which is more cost-effective.

[0019] To achieve at least one of the above objects and also other objects that will be evident from the following description, a printed circuit heat exchanger having the features defined in claim 1 is provided according to the present inventive concept.

[0020] More specifically, according to a first aspect, there is provided a printed circuit heat exchanger comprising: a heat exchanger core, a first end plate, and a second end plate, wherein the heat exchanger core comprises first heat exchanger plates and second heat exchanger plates alternatingly stacked onto each other in a stacking direction, and joined to each other, the heat exchanger core being arranged between the first end plate and the second end plate as seen along the stacking direction, wherein each first heat exchanger plate comprises a first heat exchange area comprising a number of first grooves, each first groove forming a respective first passage for a first media, the first passage extending between a first inlet configured to receive the first media, and a first outlet configured to output the first media, wherein each second heat exchanger plate comprises a second heat exchange area comprising a number of second grooves, each second groove forming a respective second passage for a second media, the second passage extending between a second inlet configured to receive the second media, and a second outlet configured to output the second media, and wherein the printed circuit heat exchanger is provided with one or more dummy holes configured to reduce a thermal mass of the printed circuit heat exchanger, wherein each dummy hole is provided in the first end plate, the second end plate, a first heat exchanger plate or a second heat exchanger plate, and wherein each dummy hole is disconnected from the first grooves and the second grooves. Hereby an improved printed circuit heat exchanger (PCHE) is provided.

[0021] The PCHE is designed for, and hence suitable to be used with, high pressures and large temperature differences. Further, PCHE is designed for great repeated cyclic temperature variations like when used in hydrogen refuelling stations.

[0022] Thus, the present invention is based on the realization that by providing one or more dummy holes configured to reduce a thermal mass of the printed circuit heat exchanger wherein each dummy hole is disconnected from the first grooves and the second grooves, a PCHE which is less prone to failure may be provided. Thus, the overall thermal mass of the PCHE will be reduced by the provision of the one or more dummy holes. By reducing the thermal mass of the PCHE, the PCHE may adapt more easily and rapidly to temperature while at the same time building up less stress in the material of the PCHE. Further, the thermal mass of the PCHE may be reduced in a region where most needed. Thus, the one or more dummy holes will reduce the thermal mass of the PCHE but will not receive the first media or the second media during use of the PCHE since the dummy holes are disconnected from the first grooves and the second grooves through which the first and second media will flow during use of the PCHE. This means in practice, that the heat PCHE may have a prolonged lifetime without negatively affecting its heat exchange performance. It also means that the PCHE may handle larger temperature variations as well as higher temperatures over its lifetime.

[0023] In practice, the thermal mass of a region or volume of the PCHE that would otherwise be dense and have a high thermal mass may be reduced by providing one or more dummy holes. In this way, differences in thermal inertia of different area, regions or volumes of the PCHE may be reduced. Such reduction of differences of thermal inertia within the PCHE may reduce material stress in the plates of the PCHE and hence in the complete PCHE. By reducing the material stress of the PCHE material fatigue may be counteracted. To this end, the one or more dummy holes are typically provided in the otherwise dense end plates and / or in otherwise dense edge regions of the first and second heat exchanger plates.

[0024] It should be noted that within the context of this application the term “dummy hole” may here mean any hole, throughgoing or blind, of a plate of the PCHE, where the hole is disconnected from the first grooves and the second grooves. Thus, a dummy hole is not in fluid communication with the first media and the second media between which heat is exchanged during use of the PCHE. Thus, a dummy hole may extend partially through an associated plate, thereby forming a blind hole. Thus, a dummy hole may extend completely through an associated plate, thereby forming a through hole. In this regard, it is to be understood that such trough hole will go through an associated plate before the plates of the PCHE are joined to each other. A through dummy hole may thus be closed when joining the plates of the PCHE. A dummy hole may have any shape. A dummy hole may have a varying depth. A dummy hole may extend along a major surface of an associated plate. A dummy hole may be closed and have vacuum therein. A dummy hole may be air filled.

[0025] Each dummy hole is provided in the first end plate, the second end plate, a first heat exchanger plate or a second heat exchanger plate. Thus, an individual dummy hole may be provided in a first heat exchanger plate, a second heat exchanger plate, the first end plate or the second endplate of the PCHE. In the following, when the wording “plate” is used, said wording may mean any first heat exchanger plate, any second heat exchanger plate, the first end plate or the second endplate of the PCHE. Thus, for example, when stated that a dummy hole is provided in a plate, the dummy hole may be provided in a first heat exchanger plate, a second heat exchanger plate, the first end plate or the second endplate of the PCHE.

[0026] Any number of dummy holes may to advantage be provided in a plate of the PCHE. Thus, any number of dummy holes may to advantage be provided in one or more of the first heat exchanger plates and the second heat exchanger plates. Thus, any number of dummy holes may to advantage be provided in the first end plate and / or in the second end plate.

[0027] In practice, one or more of the plates of the PCHE may comprise one or more dummy holes. In practice, one or more of the first heat exchanger plates of the heat exchanger core may comprise one or more dummy holes. In practice, one or more of the second heat exchanger plates of the heat exchanger core may comprise one or more dummy holes. In practice, the first end plate may comprise one or more dummy holes. In practice, the second end plate may comprise one or more dummy holes.

[0028] Further, each first heat exchanger plate comprises a first heat exchange area comprising a number of first grooves. Thus, each first heat exchanger plate comprises a first heat exchange area comprising one or more first grooves. Each first groove forms a respective first passage for the first media. Thus, each first passage extends between a first inlet of a first heat exchanger plate configured to receive the first media, and a first outlet of the first heat exchanger plate configured to output the first media.

[0029] Correspondingly, each second heat exchanger plate comprises a second heat exchange area comprising a number of second grooves. Thus, each second heat exchanger plate comprises a second heat exchange area comprising one or more second grooves. Each second groove forms a respective second passage for the second media. Thus, each second passage extends between a second inlet of a second heat exchanger plate configured to receive the first media, and a second outlet of the second heat exchanger plate configured to output the second media.

[0030] 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 exchanger area. Hence, an end plate is void of first grooves for the first media and second grooves for the second media. In practice, the first end plate is typically provided at a fist end of the heat exchanger core as seen along the stacking direction, and the second end plate is typically provided at a second opposite end of the heat exchanger core as seen along the stacking direction. Further, an end plate may be formed of 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.

[0031] A dummy hole, of the one or more dummy holes, may extend partially through a thickness of an associated plate, which is advantageous in that the thermal mass of the plate, and hence the PCHE, may be reduced while still maintaining the structural integrity of the plate.

[0032] A dummy hole, of the one or more dummy holes, may have a depth within a range corresponding to 20-90%, preferably 25-80%, more preferably 30-50% of the thickness of an associated plate. In this way, one or more dummy holes may be fabricated in the first and / or second heat exchanger plates simultaneously to fabricating the first grooves and / or the second grooves. Thus, no further manufacturing steps may be required for forming one or more dummy holes in the first and / or second heat exchanger plates.

[0033] A dummy hole, of the one or more dummy holes, may extend completely through a thickness of an associated plate, which is advantageous in that the thermal mass of the plate, and hence the PCHE, may be significantly reduced. Further, one or more dummy holes may be fabricated in the plate while for instance providing port holes in a first and / or second heat exchanger plate. Correspondingly, one or more dummy holes may be fabricated in the plate while for instance providing openings in the first and / or second end plate. Thus, no further manufacturing steps may be required for forming one or more dummy holes in a plate.

[0034] A dummy hole, of the one or more dummy holes, may have a circular shape, a semi-circular shape, a linear shape, a rectangular shape, a square shape, an oblong shape, an oval shape, a zig-zag shape, a wavy shape, a cross shape, an elliptical shape a semi-elliptical shape, or a curved shape. Thus, the one or more dummy holes may have any suitable shape. A dummy hole, of the one or more dummy holes, may have a lateral extension along a major surface of an associated plate.

[0035] A dummy hole, of the one or more dummy holes, may have a lateral extension along a major surface of an associated plate in any lateral direction.

[0036] Any dummy hole, of the one or more dummy holes, of a pair of neighboring plates may not overlap each other as seen along the stacking direction, which is advantageous in that the thermal mass of the PCHE may be significantly reduced while maintaining a high structural integrity of the PCHE. Thus, by providing any dummy holes of a pair of neighboring plates in a staggered fashion where the dummy holes do not overlap each other, may allow for that the neighboring plates may be joined to each other along the perimeter of each dummy hole. In other words, a pair of neighboring plates may be joined to each other around each dummy hole which allows for a strong joint between the neighboring plates.

[0037] The plates may be formed by a metal comprising material, and a dummy hole, of the one or more dummy holes, may be formed by etching, drilling, laser cutting, water cutting, punching or milling into the metal comprising material.

[0038] The plates may be formed by a metal comprising material.

[0039] A dummy hole, of the one or more dummy holes, may be formed by etching, drilling, laser cutting, water cutting, punching or milling.

[0040] The plates may be formed of metal.

[0041] The plates may be formed of a metal alloy.

[0042] The plates may be formed of stainless steel.

[0043] The plates may be formed of a nickel alloy.

[0044] The plates may comprise titanium.

[0045] One or more dummy holes may be formed by etching using a photoresist etch mask.

[0046] One or more dummy holes may be formed by etching using a negative photoresist etch mask.

[0047] One or more dummy holes may be formed simultaneously to forming the first grooves and / or the second grooves.

[0048] One or more dummy holes may be formed simultaneously to forming a port hole.

[0049] One or more dummy holes may be formed simultaneously to forming an opening for a port hole.

[0050] The plates may be joined by a diffusion bonding process.

[0051] The plates may be joined by brazing. The plates may be joined by welding.

[0052] A dummy hole, of the one or more dummy holes, may be provided outside the first or the second heat exchange area of an associated first or second heat exchanger plate, which is advantageous in that the thermal mass of the plate, and hence of the PCHE, may be reduced without affecting or without substantially affecting the thermal performance of the PCHE. Further, by providing a dummy hole outside the first or the second heat exchange area of an associated first or second heat exchanger plate, a through hole or a relatively speaking deep hole may be provided with a reduced risk of first media or the second media entering into the dummy hole during use of the PCHE. By “outside” is here meant that the dummy hole a hand does not coincide with the first or second heat exchange area of an associated plate as seen along the stacking direction.

[0053] A dummy hole, of the one or more dummy holes, may be provided between the first or the second heat exchange area and the perimeter of an associated first or second heat exchanger plate, which is advantageous in that the thermal mass of an edge region of the associated first or second heat exchanger plate may be significantly reduced.

[0054] Each first heat exchanger plate and each second heat exchanger plate may be provided with a plurality of dummy holes, which is advantageous in that the thermal mass may be reduced throughout the heat exchanger core. Hence, a significant reduction of the thermal mass of the PCHE may be achieved by providing a plurality of dummy holes in each first heat exchanger plate and each second heat exchanger plate. Moreover, differences in thermal inertia of different portions or regions of the PCHE may be efficiently reduced by providing a plurality of dummy holes in each first heat exchanger plate and each second heat exchanger plate.

[0055] The first and / or second end plate may be provided with a plurality of dummy holes, which is advantageous in that that the thermal mass of the first and / or second end plate may be reduced. Hence, a significant reduction of the thermal mass of the PCHE may be achieved by providing a plurality of dummy holes in the first and / or second end plate. Moreover, differences in thermal inertia of different portions or regions of the PCHE may be efficiently reduced by providing a plurality of dummy holes in the first and / or second end plate.

[0056] The plurality of dummy holes may be distributed over at least a major portion of an associated major surface of the first and / or second end plate, which is advantageous in that the thermal mass of at least a major portion of the first and / or second end plate may be reduced. Further, by distributing the plurality of dummy holes over at least a major portion of an associated major surface of the first and / or second end plate, one or more openings for a port hole may for example be provided without interfering with the plurality of dummy holes.

[0057] The plurality of dummy holes may be distributed over an entire associated major surface of the first and / or second end plate.

[0058] The first end plate and / or the second end plate may be formed by a stack of subplates stacked onto each other in the stacking direction, and one or more of the subplates may be provided with a dummy hole, of the one or more dummy holes, which is advantageous in that first end plate and / or the second end plate may be designed more freely while still reducing the thermal mass thereof. Further, by forming the first end plate and / or the second end plate by a stack of subplates, joining of the first end plate and / or the second end plate to the heat exchanger core may be facilitated since the stack of subplates may more easily flex and follow an end surface of the heat exchanger core as opposed to if a solid first and / or second end plate where to be used.

[0059] The first end plate and / or the second end plate may be formed by a stack of subplates stacked onto each other in the stacking direction. One or more of the subplates may be provided with a dummy hole, of the one or more dummy holes.

[0060] Any dummy hole, of the one or more dummy holes, of a pair of neighboring subplates of the first end plate and / or the second end plate may not overlap each other as seen along the stacking direction.

[0061] The stack of subplates may comprise one or more subplates provided with a dummy hole, of the one or more dummy holes, arranged between a pair of subplates void of dummy holes. By the stack of subplates comprising one or more subplates provided with a dummy hole, of the one or more dummy holes, arranged between a pair of subplates void of dummy holes, the thermal mass of the first and / or second end plate may be reduced in an invisible manner where the dummy holes may not be visible form an outside of the PCHE. Further by the stack of subplates comprising one or more subplates provided with a dummy hole, of the one or more dummy holes, arranged between a pair of subplates void of dummy holes, the thermal mass of the first and / or second end plate may be reduced while assisting in keeping the dummy holes disconnected from the first grooves and the second grooves.

[0062] The stack of subplates may comprise two or more subplates provided with a plurality of dummy holes, of the one or more dummy holes, arranged between a pair of subplates void of dummy holes, and the plurality of dummy holes may be distributed over at least a major portion of an associated major surface of the two or more subplates, which is advantageous in that the thermal mass of the first end plate and / or the second end plate may be reduced over at least a major portion of the first and / or second end plate. Further, a significant reduction of the thermal mass of the first end plate and / or the second end plate may be achieved in an invisible manner.

[0063] Furthermore, a significant reduction of the thermal mass of the first end plate and / or the second end plate may be achieved while assisting in keeping the dummy holes disconnected from the first grooves and the second grooves.

[0064] The stack of subplates may comprise two or more subplates provided with a plurality of dummy holes, of the one or more dummy holes, arranged between a pair of subplates void of dummy holes.

[0065] The plurality of dummy holes may be distributed over at least a major portion of an associated major surface of the two or more subplates.

[0066] Each first and second heat exchanger plate may comprises a pair of first port holes and a pair of second port holes, wherein each first inlet and each first outlet communicate directly with a respective first port hole of an associated first heat exchanger plate, wherein each second inlet and each second outlet communicate directly with a respective second port hole of an associated second heat exchanger plate, wherein an end plate, of the first end plate and the second end plate, comprises a first opening in fluid communication with a first port hole, and wherein an end plate of the first end plate and the second end plate, comprises a second opening in fluid communication with a second port hole.

[0067] Thus, the pair of first port holes of each first and second heat exchanger plates may form a pair of first port hole channels extending through the heat exchanger core. Correspondingly, the pair of second port holes of each first and second heat exchanger plates may form a pair of second port hole channels extending through the heat exchanger core.

[0068] In this way, the first media may be received at each first inlet of the first heat exchanger plates via one of the first port hole channels and outputted into the other one of the first port hole channels via each first outlet of the first heat exchanger plates. Correspondingly, the second media may be received at each second inlet of the second heat exchanger plates via one of the second port hole channels and outputted into the other one of the second port hole channels via each second outlet of the second heat exchanger plates. Hence, the first media and the second media may be distributed efficiently internally of the heat exchanger core.

[0069] Further, the first end plate may comprise zero or more openings. Correspondingly, the second end plate may comprise zero or more openings. The PCHE may comprise a pair of first openings in fluid communication with a respective first port hole of the pair of first port holes. Hence, the PCHE may comprise a pair of first openings in fluid communication with a respective first port hole channel.

[0070] The PCHE may comprise a pair of second openings in fluid communication with a respective second port hole of the pair of second port holes. Hence, the PCHE may comprise a pair of second openings in fluid communication with a respective second port hole channel.

[0071] In practice, PCHE may comprise a pair of first openings in fluid communication with a respective first port hole of the pair of first port holes, and a pair of second openings in fluid communication with a respective second port hole of the pair of second port holes. 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.

[0072] The printed circuit heat exchanger may further comprise first inlet and outlet headers, and second inlet and outlet headers, wherein each first inlet communicates directly with a first inlet volume defined by the first inlet header and the heat exchanger core, wherein each first outlet communicates directly with a first outlet volume defined by the first outlet header and the heat exchanger core, wherein each second inlet communicates directly with a second inlet volume defined by the second inlet header and the heat exchanger core, and wherein each second outlet communicates directly with a second outlet volume defined by the second outlet header and the heat exchanger core.

[0073] In this way, the first media may be received at each first inlet of the first heat exchanger plates via the first inlet volume defined by the first inlet header and the heat exchanger core, and outputted form each first outlet of the first heat exchanger plates into the first outlet volume defined by the first outlet header and the heat exchanger core. Correspondingly, the second media may be received at each second inlet of the second heat exchanger plates via the second inlet volume defined by the second inlet header and the heat exchanger core, and outputted form each second outlet of the second heat exchanger plates into the second outlet volume defined by the second outlet header and the heat exchanger core.

[0074] Hence, the first media and the second media may be distributed efficiently externally of the heat exchanger core by means of the first inlet and outlet headers, and the second inlet and outlet headers.

[0075] 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.

[0076] 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.

[0077] Brief Description of the Drawings

[0078] The above and other aspects of the present inventive concept will now be described in more detail, with reference to appended figures showing variants. The figures should not be considered limiting, instead, they are used for explaining and understanding. In fact, in the figures, several dummy holes are illustrated in the respective figures although just a single dummy hole in a single location at a single plate may be used to advantage according to the inventive concept.

[0079] 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.

[0080] Fig. 1 is a schematic example perspective exploded view of a PCHE according to an embodiment. Fig. 2 is a schematic plane view of a first heat exchanger plate of the heat exchanger core of the PCHE of Fig. 1.

[0081] Fig. 3 is a schematic plane view of a second heat exchanger plate of the heat exchanger core of the PCHE of Fig. 1.

[0082] Fig. 4 is a schematic example perspective exploded view of a PCHE according to another embodiment.

[0083] Fig. 5 is a schematic plane view of a first heat exchanger plate of the heat exchanger core of the PCHE of Fig. 4.

[0084] Fig. 6 is a schematic plane view of a second heat exchanger plate of the heat exchanger core of the PCHE of Fig. 4.

[0085] Fig. 7 is a schematic plane view of a first heat exchanger plate for the PCHE of Fig. 1 according to an example embodiment.

[0086] Fig. 8 is a schematic plane view of a second heat exchanger plate for the PCHE of Fig. 1 according to an example embodiment.

[0087] Fig. 9 is a schematic example perspective view of an end plate, formed of a stack of subplates, which may be used in the PCHEs of Figs. 1 and 4.

[0088] Fig. 10 is a schematic example perspective view of a general plate provided with different example designs of dummy holes.

[0089] Detailed Description

[0090] 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.

[0091] Example embodiments of a printed circuit heat exchanger (PCHE) 1 will 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 axes L and S consistently refer to lateral direction L of the PCHE 1 and stacking direction S of the PCHE 1. The term “lateral” direction L refers to any directions parallel to an extension plane of the plates of the PCHE 1. The term “stacking” direction S refers to a direction parallel to a normal direction of the extension plane of the plates of the PCHE 1. Now turning to Figs. 1 , 2 and 3. Fig 1 schematically illustrates by way of example a PCHE 1. The PCHE comprises a heat exchanger core 10, a first end plate 50 and a second end plate 60.

[0092] The heat exchanger core 10 may also be referred to as a plate package. The depicted heat exchanger core 10 will in the following be referred to as a core 10.

[0093] The core 10 is formed of a number of heat exchanger plates 100, 200. More specifically, the core 10 is formed by a number of first heat exchanger plates 100 and number second heat exchanger plates 200. Any number of first and second heat exchanger plates may be used to advantage in the core 10. The design of the first heat exchanger plates 100 of Fig 1. are illustrated in Fig. 2, to which reference is also made. Correspondingly, the design of the second heat exchanger plates 200 of Fig. 1 are illustrated in Fig. 3, to which reference is also made.

[0094] The first heat exchanger plates 100 and the second heat exchanger plates 200 are alternatingly stacked onto each other in a stacking direction S as illustrated in Fig. 1. It is to be noted that in Fig. 1 , the first and second heat exchanger plates 100, 200 are illustrated as being separated in order to clearly illustrate the design of the heat exchanger plates 100, 200. However, as is to be understood, the first heat exchanger plates 100 and the second heat exchanger plates 200 are joined to each other to form the core 10.

[0095] The first and second heat exchanger plates 100, 200 are typically formed from metal plates or sheets. The metal plates form which the first and second heat exchanger plates 100, 200 are formed may for example be stainless steel plates. However, other materials such as various other metal alloys may be used to advantage.

[0096] As illustrated in Fig. 1 , the core 10 is arranged between the first end plate 50 and the second end plate 60 as seen along the stacking direction S.

[0097] The first and second heat exchanger plates 100, 200 and the first and second end plates 50, 60 are typically joined to each other by a diffusion bonding process. Diffusion bonding as such is known in the art and will not be described in detail here. However, when the first and second heat exchanger plates 100, 200 and the first and second end plates 50, 60 are joined via a diffusion bonding process, the first and second heat exchanger plates 100, 200 and the first and second end plates 50, 60 are in short stacked onto each other and heated in a furnace under vacuum conditions while subjected to pressure. In this way, the first and second heat exchanger plates 100, 200 and the first and second end plates 50, 60 are joined to each other without using any solder or welding material. However, before the first and second heat exchanger plates 100, 200 and the first and second end plates 50, 60 are joined to each other, the first and second heat exchanger plates 100, 200 and the first and second end plates 50, 60 are in practice subjected to further processing steps aiming at forming the first and second heat exchanger plates 100, 200 and the first and second end plates 50, 60.

[0098] As illustrated in Fig. 1 the first end plate 50 may be formed by stack of subplates 50:1, 50:2 stacked onto each other in the stacking direction S. The depicted first endplate 50 is formed by a stack of five subplates 50:1 , 50:2. It is however to be understood that the fist end plate 50 may be formed of a single plate. Thus, the first end plate may not be a stack of subplates 50:1, 50:2. On the other hand, the first end plate 50 may be formed of any number of subplates 50:1, 50:2.

[0099] Correspondingly, as illustrated in Fig. 1 the second end plate 60 may formed by stack of subplates 60:1 , 60:2 stacked onto each other in the stacking direction S. The depicted second endplate 60 is formed by a stack of five subplates 60:1 , 60:2. It is however to be understood that the second end plate 60 may be formed of a single plate. Thus, the second end plate 60 may, like the first end plate 50, not be a stack of subplates 60:1, 60:2. On the other hand, the second end plate 60 may be formed of any number of subplates 60: 1 , 60:2.

[0100] According to an example, the first and second end plates 50, 60 may have a thickness in a range of 3 - 10,0 mm. According to an example, the subplates 50:1, 50:2, 60:1 , 60:2 may have a thickness in a range of 1 ,5 - 2 mm.

[0101] The depicted first end plate 50 and the second end plate 60 have the same general structure and will in the following be described in more detail jointly. As illustrated in Fig. 1 , the first and second endplates 50, 60 each include three subplates 50:2, 60:2 provided with a plurality of dummy holes 500. The three subplates 50:2, 60:2 provided with dummy holes 500 are arranged between a pair of subplates 50:1, 60:1 void of dummy holes. The dummy holes 500 are isolated from the first media and the second media during use of the PCHE. In other words, each dummy hole 500 is disconnected from any structure of the PCHE which is configured to receive the first media and the second media during use of the PCHE.

[0102] Further, the first and second heat exchanger plates 100, 200 are provided with a plurality of dummy holes 500. In the following, dummy holes 500 of the first and second end plates 50, 60 will be described first. Thereafter, the design of the first and second heat exchanger plates 100, 200 will be described along with the design of the dummy holes 500 of the first and second heat exchanger plates 100, 200. The design of the dummy holes 500 may vary. In this regard, different relevant designs of the dummy holes 500 will be described in greater detail hereinafter while referring to Figs. 1-10. In doing so, specific designs of the dummy holes 500 will be referred to as 500:XX, where XX denotes a particular design of a dummy hole 500. The refence numeral 500 is still referring to all depicted dummy holes of any design provided in any plate 50, 60, 100, 200 of the PCHE 1.

[0103] As illustrated in Fig. 1, the plurality of dummy holes 500 of the end plates 50, 60 may be distributed over a major portion of the three subplates 50:2, 60:2. In fact, in Fig. 1 , the plurality of dummy holes 500 is distributed over more or less a complete major surface of the three subplates 50:2, 60:2. It is however to be understood that the plurality of dummy holes 500 of the three subplates 50:2, 60:2 may be distributed over any portion or over a plurality of portions of the three subplates 50:2, 60:2. Further, any number of dummy holes 500 may be used to advantage the subplates 50:2, 60:2. In Fig. 1 , about 230 dummy holes 500 are provided in each one of the three subplates 50:2, 60:2. It is however to be understood that number of dummy holes may vary greatly. Even a single dummy hole 500 may be provided in a single end plate 50, 60 or in a single subplate 50:1, 50:2, 60:1 , 60:2. Further, dummy holes 500 may be provided in one or more of the subplates 50:1, 50:2, 60:1 , 60:2, including the outermost subplates of an end plate 50, 60. Moreover subplates 50:1, 60:1 void of dummy holes 500 may be arranged between subplates 50:2, 60:2 provided with dummy holes 500. Thus, to sum up, any number of dummy holes 500 may be provided at any location of the first end plate 50 and the second end plate 60.

[0104] The illustrated dummy holes 500 of the end plates 50, 60 of Fig. 1 are all illustrated as being circular through holes. In other words, the dummy holes 500 extends completely through the thickness of an associated plate. Such through going dummy holes 500 may be formed by etching, drilling, laser cutting, water cutting, punching or milling into the material of the first or second end plate 50, 60. The same holds true for dummy holes of the first and second heat exchanger plates 100, 200. More specifically, as illustrated in Fig. 1 , the dummy holes 500 may be formed by etching, drilling, laser cutting, water cutting, punching or milling into the material of the relevant subplates 50:2, 60:2.

[0105] As illustrated in Fig. 1 , the dummy holes 500 of neighboring subplates 50:2, 60:2 may not overlap each other as seen along the stacking direction S. In other words, the dummy holes 500 of neighboring subplates 50:2, 60:2 may be arranged in a staggered fashion as seen along the stacking direction S. Thus, the dummy holes 500 of neighboring subplates 50:2, 60:2 are not in fluid communication with each other. This arrangement of the dummy holes 500 generally provides for a strong bond between the neighboring subplates 50:2, 60:2 and an overall high mechanical integrity of the PCHE 1.

[0106] By providing dummy holes 500 in the first and second end plates 50, 60 as described above, the thermal mass of the first and second end plates 50, 60 may be significantly reduced. In this way, the first and second end plates 50, 60 may more quickly change temperature when subjected to temperature variations when the PCHE is used. Thus, undesired material stress in the first and second end plates 50, 60 may be mitigated. At the same time, the difference of thermal inertia between the first and second end plates 50, 60 and the first and second heat exchanger plates 100, 200 may be reduced. Such reduction of the difference of thermal inertia means in practice that the first and second end plates 50, 60 and the first and second heat exchanger plates 100, 200 may change their temperatures in a more uniform way, thus mitigating undesired material stress which otherwise may result in material fatigue and ultimately material rupture.

[0107] As illustrated in Figs. 1 and 2, each first heat exchanger plate 100 may comprise a pair of first port holes 150 and a pair of second port holes 160. Correspondingly, as illustrated in Figs. 1 and 3, each second heat exchanger plate 200 may comprise a pair of first port holes 150 and a pair of second port holes 160. As illustrated in Fig. 1, the first port holes 150 of the first heat exchanger plates 100 and of the second heat exchanger plates 200 are typically aligned so as to form a pair of port hole channels for a first media. Correspondingly, the second port holes 160 of the first heat exchanger plates 100 and of the second heat exchanger plates 200 are typically aligned so as to form a pair of port hole channels for a second media.

[0108] As illustrated in Figs. 1 and 2, each first heat exchanger plate 100 comprises, a first heat exchange area A1. The depicted first heat exchange area A1 of each first heat exchanger plate 100 comprises a plurality of first groves 102. The first grooves 102 are each forming a respective first passage 104 for the first media, i.e. the media associated with the first port holes 150 and the first port hole channels. The first passages 104 are extending between respective a first inlet 104:1 and respective a first outlet 104:2. The first inlet 104:1 is configured to receive the first media. The first outlet 104:2 is configured to output the first media. In practice, the first passages 104 are extending between the first portholes 150 of the associated first heat exchanger plate 100. Thus, each first inlet 104:1 and each first outlet 104:2 communicate directly with a first port hole 150 of an associated first heat exchanger plate 100. Correspondingly, as illustrated in Figs. 1 and 3, each second heat exchanger plate 200 comprises, a second heat exchange area A2. The depicted second heat exchange area A2 of each second heat exchanger plate 200 comprises a plurality of second grooves 202. The second grooves 202 are each forming a second passage 204 for the second media, i.e. the media associated with the second port holes 160 and the second port hole channels. The second passages 204 are extending between a respective second inlet 204:1 and a respective second outlet 204:2. The second inlet 204:1 is configured to receive the second media. The second outlet 204:2 is configured to output the second media. In practice, the second passages 204 are extending between the second portholes 160 of the associated second heat exchanger plate 200. Thus, each second inlet 204:1 and each second outlet 204:2 communicate directly with a respective second port hole 160 of an associated second heat exchanger plate 200.

[0109] The depicted PCHE 1 is designed to be used in a hydrogen refueling station. To this end, the first heat exchanger plates 100 comprises the first grooves 102 for feeding liquefied hydrogen, as a first media, between the first port holes 150 via the first heat exchange area A1. Correspondingly, the second heat exchanger plates 200 comprises the second grooves 202 for feeding a refrigerant, such as water, as a second media, between the second port holes 160 via the second heat exchange area A2. Thus, when the first media and the second media are fed via the first and second heat exchange areas A1, A2 heat will be exchanged between the first and second media depending on their temperatures. Typically, when the first media is liquefied hydrogen, the liquefied hydrogen will be cooled by the second media (water) while the medias are fed via the heat exchange areas A1, A2.

[0110] The depicted first grooves 102 and the second grooves 202 of Figs. 1 , 2 and 3 are formed via an etching process in which the metal of the first and second heat exchanger plates 100, 200 are etched away to form a dedicated pattern of grooves, i.e. the first grooves 102 in case of a first heat exchanger plate 100 and the second grooves in case of a second heat exchanger plate 200. Metal etching as such is known in the art and will not be described in detail here. However, when etching the first grooves 102 and the second grooves 202, an etch mask formed of a photoresist is typically used. The photoresist may be a positive photoresist or a negative photoresist. A negative photoresist is generally desired due to its relatively speaking high resistance to the etch chemistry used to etch the grooves 102, 202. When etching the grooves 102, 202, a major surface of a plate 100, 200 to be etched is typically coated with a photoresist, whereafter the photoresist is exposed with the groove pattern to be etched in case of positive photoresist or with an inverse of the groove pattern to be etched in case of negative photoresist. The photoresist is then developed and used as an etch mask for the etch chemistry used to etch the metal at the major surface of the plate 100, 200 to be etched.

[0111] Further, as illustrated in Figs. 1, 2 and 3, the first and second heat exchanger plates 100, 200 of the core 10 of the PCHE 1 comprises a number of dummy holes 500. The dummy holes 500 of the first and second heat exchanger plates 100, 200 are formed like grooves which extend laterally along a major surface of the associated first and second heat exchanger plates 100, 200. Thus, the dummy holes 500 of the first and second heat exchanger plates 100, 200 extend partially through a thickness of an associated plate 100, 200. Further, each dummy hole 500 of the first and second heat exchanger plates 100, 200 is disconnected from the first grooves 102 and the second grooves 102. Thus, all dummy holes 500 of any plate 50, 60, 100, 200 of the PCHE 1 are disconnected from the first grooves 102 and the second grooves 102. In other words, the dummy holes of any plate 50, 60, 100, 200 of the PCHE 1 are configured to not receive the first media or the second media when the PCHE 1 is used.

[0112] As illustrated in Figs. 2 and 3, the dummy holes 500 are extending in different lateral directions and have different lateral extensions. More specifically, the dummy holes of the first and second heat exchanger plates 100, 200 are provided in form of groups of dummy holes in form of grooves where the individual dummy holes 500: 11 , 500:21 extend straight in parallel to a portion of the perimeter 106, 206 of an associated first and second heat exchanger plate 100, 200. Thus, the dummy holes 500:11, 500:21 of different groups of dummy holes may extend in different lateral directions L as illustrated in Figs 2 and 3.

[0113] Further, a respective group of dummy holes in form of grooves where the individual dummy holes 500:12 extend straight partially between the first heat exchanger area A1 and the dummy holes 500:11 are provided at the first heat exchanger plates 100 as illustrated in Fig. 2.

[0114] The depicted dummy holes 500 of the first and second heat exchanger plates 100, 200 of Figs. 2 and 3 are like the first grooves 102 and the second grooves 202 etched into the material of the first and second heat exchanger plates 100, 200. In other words, dummy holes 500 of the first and second heat exchanger plates 100, 200 are etched into a major surface of the first heat exchanger plates 100. Correspondingly, dummy holes 500 are etched into a major surface of the second heat exchanger plates 200.

[0115] Thus, the depicted dummy holes 500 of the first and second heat exchanger plates 100, 200 of Figs. 2 and 3 are provided outside the first or the second heat exchange area A1, A2 of an associated first or second heat exchanger plate 200. Thus, the depicted dummy holes 500 of the first and second heat exchanger plates 100, 200 of Figs. 2 and 3 are provided between the first or the second heat exchange area A1, A2 and the perimeter 106, 206 of an associated first or second heat exchanger plate 100, 200.

[0116] Dummy holes 500 of the above-described type which do not extend completely through an associated plate 50, 60, 100, 200 may typically be etched to have a depth within a range corresponding to 20-90%, preferably 25-80%, more preferably 30-50% of a thickness of the associated plate 50, 60, 100, 200. Irrespective of the fact the dummy holes 500 may be etched simultaneously to the first grooves 102 and the second grooves 202, the depth of the dummy holes 500 may be adapted by tailoring a line width of the etch mask used for etching the first grooves 102, the second grooves 202 and the dummy holes 500, as is known in the art.

[0117] According to an example, the first and second heat exchanger plates 100, 200 may have a thickness in a range of 1 ,5 - 2,0 mm. In such case, the dummy holes 500 thereof may be etched to have a depth of about 0,65 mm. However, the depth of the dummy holes 500 may be about 1 ,2 mm to increase the thermal mass reduction provided by the dummy holes 500. However, it is to be understood that any suitable thickness of the first and second heat exchanger plates 100, 200 may be used to advantage. Also, any suitable depth of the dummy holes 500 may be used to advantage.

[0118] As illustrated in Figs. 2 and 3, the dummy holes 500 of neighboring first and second heat exchanger plates 100, 200 may at least partially overlap each other as seen along the stacking direction S. Oving from the fact that the depicted dummy holes 500 of the first and second heat exchanger plates 100, 200 of Figs. 2 and 3 extend partially through an associated first or second heat exchanger plates 100, 200, the dummy holes 500 of the first and second heat exchanger plates 100, 200 will be disconnected from each other. This arrangement of the dummy holes 500 provides for a strong bond between the neighboring first and second heat exchanger plates 100, 200 and an overall high mechanical integrity of the PCHE 1.

[0119] By providing the dummy holes 500 in the first and second heat exchanger plates 100, 200 as described above, the thermal mass of the first and second heat exchanger plates 100, 200 may be significantly reduced. In this way, the first and second heat exchanger plates 100, 200 may more quickly change temperature when subjected to temperature variations when the PCHE is used. Thus, undesired material stress in the first and second heat exchanger plates 100, 200 may be mitigated. At the same time, the difference of thermal inertia between the first and second end plates 50, 60 and the first and second heat exchanger plates 100, 200 may be reduced. Such reduction of the difference of thermal inertia means in practice that the first and second end plates 50, 60 and the first and second heat exchanger plates 100, 200 may change their temperatures in a more uniform way, as described above, thus mitigating undesired material stress which otherwise may result in material fatigue and ultimately material rupture.

[0120] Oving from the fact that the first and second heat exchanger plates 100, 200 of and the first and second end plates 50, 60 of the PCHE 1 typically are joined to each other by diffusion bonding under vacuum conditions, the dummy holes 500 may typically have a vacuum therein. This holds true as long as the dummy holes 500 are not open to the ambient. In such case where a dummy holes 500 is open to the ambient, the dummy holes will for natural reasons be filled with air.

[0121] Further, as illustrated in Fig. 1, the first end plate 50 may comprise a pair of first openings 170 and a pair of second openings 180. In the depicted first end plate 50 of Fig. 1 , the first openings 170 and the second openings 180 are all extending through the subplates 50:1 , 50:2 forming the first end plate 50. The first openings 170 are in fluid communication with a respective port hole channel formed by the first port holes 150. Correspondingly, the second openings 180 are in fluid communication with a respective port hole channel formed by the second port holes 160. Thus, a first media may be fed into the core 10 via one of the first openings 170 and extracted from the core 10 via the other one of the first openings 170. Hence, the first media may be fed between the first openings 170. Correspondingly, a second media may be fed into the core 10 via one of the second openings 180 and extracted from the core 10 via the other one of the second openings 180. Hence, the second media may be fed between the second openings 180. In this way, heat may be exchanged between the first media and the second media.

[0122] It is to be understood that the first openings 170 and the second openings 180 do not need to be provided at the first end plate 50. In practice, the first openings 170 may be provided at the first end plate 50 as illustrated in Fig. 1 , or at the second end plate 60. Further, one of the first openings 170 may be provided at the fist end plate 50 and the other one of the first openings 170 may be provided at the second end plate 60. Correspondingly, the second openings 180 may be provided at the first end plate 50 as illustrated in Fig. 1, or at the second end plate 60. Further, one of the second openings 180 may be provided at the fist end plate 50 and the other one of the second openings 180 may be provided at the second end plate 60. For example, the first openings 170 and the second openings 180 may be provided at opposite end plates 50, 60 For example, the first openings 170 and one of the second openings 180 may be provided at the first end plate 50, whereas the other one of the second openings 180 may be provided at the second end plate 60. For example, the second openings 180 and one of the first openings 170 may be provided at the first end plate 50, whereas the other one of the first openings 170 may be provided at the second end plate 60.

[0123] Now turning to Figs. 4, 5 and 6. Fig. 4 illustrates an alternative design of a PCHE 1. The PCHE 1 of Fig. 4 is similar to the PCHE 1 of Fig. 1. Given the similarities, mainly differences between the respective PCHE:s 1 will be described in the following. Like the PCHE 1 of Fig. 1, the PCHE 1 of Fig. 4 comprises a heat exchanger core 10, a first end plate 50 and a second end plate 60. The first end plate 50 and a second end plate 60 of the PCHE 1 of Fig. 4 are of the same type as the second end plate 60 of the PCHE 1 of Fig. 1.

[0124] However, as opposed to the PCHE 1 of Fig. 1 , the PCHE 1 of Fig. 4 comprises first inlet and outlet headers 30, 35, and second inlet and outlet headers 40, 45.

[0125] The first inlet and outlet headers 30, 35 are configured to provide the first media to the core 10 and to extract the first media from the core 10. Correspondingly, the second inlet and outlet headers 40, 45 are configured to provide the second media to the core 10 and to extract the second media from the core 10. Given the first inlet and outlet headers 30, 35, and second inlet and outlet headers 40, 45, the first and second heat exchanger plates 100, 200 of the PCHE of Fig. 4 are void of any port holes.

[0126] Thus, as illustrated in Figs. 4 and 5, each first inlet 104:1 may communicate directly with a first inlet volume V30 defined by the first inlet header 30 and the heat exchanger core 10. Further, as illustrated in Figs. 4 and 5, each first outlet 104:2 may communicate directly with a first outlet volume V35 defined by the first outlet header 35 and the heat exchanger core 10.

[0127] Correspondingly, as illustrated in Figs. 4 and 6, each second inlet 204:1 may communicate directly with a second inlet volume V40 defined by the second inlet header 40 and the heat exchanger core 10. Further as illustrated in Figs. 4 and 6, each second outlet 204:2 may communicate directly with a second outlet volume V45 defined by the second outlet header 45 and the heat exchanger core 10.

[0128] Further, as best illustrated in Fig. 5, each first heat exchanger plate 100 of the PCHE 1 of Fig. 4 is provided with a plurality of dummy holes 500. Correspondingly, as best illustrated in Fig. 6, each second heat exchanger plate 200 of the PCHE 1 of Fig. 4 is provided with a plurality of dummy holes 500. The dummy holes 500 of the first and second heat exchanger plates 100, 200 of Figs. 5 and 6 are provided in the form of grooves which extend partially through a thickness of an associated first or second heat exchanger plate 100, 200. Thus, the dummy holes 500 may generally be of the type described above in conjunction to Figs. 2 and 3.

[0129] The depicted dummy holes 500 of the first and second heat exchanger plates 100, 200 of Figs. 5 and 6 include groups of wavy or zigzag patterned dummy holes where the individual dummy holes 500:13, 500:23 extend in a zigzag fashion along a portion of the perimeter 106, 206 of an associated first and second heat exchanger plate 100, 200. Thus, the dummy holes 500:13, 500:23 of different groups of dummy holes may extend in different lateral directions L as illustrated in Figs 5 and 6.

[0130] Further, the depicted dummy holes 500 of the first and second heat exchanger plates 100, 200 of Figs. 5 and 6 include groups of straight dummy holes where the individual dummy holes 500:14, 500:24 extend straight along a portion of the perimeter 106, 206 of an associated first and second heat exchanger plate 100, 200.

[0131] Further, a respective group of dummy holes in form of grooves where the individual dummy holes 500:25 extend straight inwards from close to the perimeter 106 towards the first exchanger area A1 are provided at the second heat exchanger plates 200 as illustrated in Fig. 6.

[0132] The depicted dummy holes 500 of the first and second heat exchanger plates 100, 200 of Figs. 5 and 6 are like the first grooves 102 and the second grooves 202 etched into the material of the first and second heat exchanger plates 100, 200. In other words, dummy holes 500 of the first and second heat exchanger plates 100, 200 are etched into a major surface of the first heat exchanger plates 100. Correspondingly, dummy holes 500 are etched into a major surface of the second heat exchanger plates 200.

[0133] Now turning to Fig. 7. Fig. 7 illustrates an alternative design of a first heat exchanger plate 100 for the PCHE 1 of Fig. 1. Thus, the heat exchanger plate 100 of Fig. 7 may be used in the core 10 of the PCHE 1 of Fig. 1. The heat exchanger plate 100 of Fig. 7 may replace all or some of the first heat exchanger plates 100 of the core 10 of the PCHE 1 of Fig. 1.

[0134] The first heat exchanger plate 100 of Fig. 7 is similar to the first heat exchanger plate 100 of Fig. 2. Given the similarities, only differences between the respective first heat exchanger plates 100 will be described in the following. As illustrated in Fig. 7, the first heat exchanger plate 100 of Fig. 7 is provided with a plurality of dummy holes 500. The dummy holes 500 the first heat exchanger plate 100 of Fig. 7 include groups of circular dummy holes where the individual dummy holes 500:16 are formed of through going circular dummy holes 500:16. Hence, the dummy holes 500:16 the first heat exchanger plate 100 of Fig. 7 are of the same general type as the dummy holes of the first and second end plates 50, 60 of Fig. 1. Further, the groups of the dummy holes 500:16 of the first heat exchanger plate 100 of Fig. 7 are provided along opposites sides of the first heat exchanger plate 100.

[0135] Further, as illustrated in Fig. 7, the dummy holes 500 the first heat exchanger plate 100 of Fig. 7 include groups of straight dummy holes where the individual dummy holes 500:17 are formed of straight through going dummy holes 500:17 extending in parallel to a region of the perimeter 106 of the first heat exchanger plate 100. Hence, the dummy holes 500:17 the first heat exchanger plate 100 of Fig. 7 are generally of the same type as the dummy holes of the first and second end plates 50, 60 of Fig. 1 , although the dummy holes 500:17 have a lateral extension along a major surface of the first heat exchanger plate of Fig. 7. Further, the groups of the dummy holes 500:17 of the first heat exchanger plate 100 of Fig. 7 are provided along opposites sides of the first heat exchanger plate 100.

[0136] Further, the first heat exchanger plate of Fig. 7 is void of any dummy holes in the location of the dummy holes 500:12 of Fig. 2.

[0137] Now turning to Fig. 8. Fig. 8 illustrates an alternative design of a second heat exchanger plate 200 for the PCHE 1 of Fig. 1. Thus, the heat exchanger plate 200 of Fig. 8 may be used in the core 10 of the PCHE 1 of Fig. 1. The heat exchanger plate 100 of Fig. 8 may replace all or some of the second heat exchanger plates 200 of the core 10 of the PCHE 1 of Fig. 1.

[0138] The second heat exchanger plate 200 of Fig. 8 is similar to the second heat exchanger plate 200 of Fig. 2. Given the similarities, only differences between the respective first heat exchanger plates 200 will be described in the following. As illustrated in Fig. 8, the second heat exchanger plate 200 of Fig. 8 is provided with a plurality of dummy holes 500. The dummy holes 500 the second heat exchanger plate 200 of Fig. 8 include groups of circular dummy holes where the individual dummy holes 500:26 are formed of through going circular dummy holes 500:26. Hence, the dummy holes 500:26 the second heat exchanger plate 200 of Fig. 8 are of the same general type as the dummy holes of the first and second end plates 50, 60 of Fig. 1 , and of the same type as the dummy holes 500:16 of the first heat exchanger plate 100 of Fig. 7. Further, the groups of the dummy holes 500:26 of the second heat exchanger plate 200 of Fig. 7 are provided along opposites sides of the first heat exchanger plate 200. Further, as illustrated in Fig. 8, the dummy holes 500 the second heat exchanger plate 200 of Fig. 8 include groups of straight dummy holes where the individual dummy holes 500:27 are formed of straight through going dummy holes 500:27 extending in parallel to a region of the perimeter 206 of the second heat exchanger plate 200. Hence, the dummy holes 500:27 the second heat exchanger plate 200 of Fig. 8 are generally of the same type as the dummy holes 500:17 of the first heat exchanger plate 100 of Fig. 7. Moreover, the dummy holes 500:27 the second heat exchanger plate 200 of Fig. 8 are generally of the same type as the dummy holes of the first and second end plates 50, 60 of Fig. 1 , although the dummy holes 500:27 have a lateral extension along a major surface of the second heat exchanger plate 200 of Fig. 8. Further, the groups of the dummy holes 500:27 of the second heat exchanger plate 200 of Fig. 8 are provided along opposites sides of the first heat exchanger plate 100.

[0139] Now turning to Fig. 9. Fig. 9 illustrates an alternative design of an end plate 50,60. The end plate 50,60 depicted in Fig. 9 may be used instead of the second first end plate and / or instead of the second end plate 60 in the PCHE 1 of Fig. 4. Further, the end plate 50,60 depicted in Fig. 9 may be used instead of the second first end plate 50 and / or instead of the second end plate 60 in the PCHE 1 of Fig. 1. However, openings corresponding to the openings 170, 180 may have to be provided when the end plate 50,60 depicted in Fig. 9 is to be used in the PCHE 1 of Fig. 1.

[0140] The end plate 50,60 depicted in Fig. 9 is formed by a stack of subplates 50,60:1 , 50,60:2 stacked onto each other in the stacking direction S. The depicted end plate 50,60 is formed by a stack of four subplates 50,60:1 , 50,60:2.

[0141] As illustrated in Fig. 9, the endplate 50,60 includes two subplates 50,60:2 provided with a plurality of dummy holes 500. The two subplates 50,60:2 provided with dummy holes 500 are arranged between a pair of subplates 50,60:1 void of dummy holes. The dummy holes 500 are isolated from the first media and the second media during use of the PCHE. In other words, each dummy hole 500 is disconnected from any structure of the PCHE which is configured to receive the first media and the second media during use of the PCHE.

[0142] As illustrated in Fig. 9, the dummy holes 500 of the two subplates 50,60:2 provided with dummy holes 500 are formed of dummy holes 500 in form of grooves. Thus, the depicted dummy holes 500 of the two subplates 50,60:2 are extending partially through a thickness of the associated subplates 50,60:2. The dummy holes 500 of the endplate 50,60 of Fig. 9 may however be provided with any type of the dummy holes 500 described above in order to reduce a thermal mass thereof. Now turning to Fig. 10. As already mentioned above, the dummy holes 500 may have different shapes. In fact, any suitable shape of the dummy holes may be used to advantage. Fig. 10 illustrates a general plate 20. The general plate 20 is drawn for illustrative purposes and is intended to clearly illustrate that the dummy holes 500 may be provided in numerous shapes. Further, the general plate 20 is drawn to clearly illustrate that the dummy holes 500 irrespective of their shape may be provided as through going dummy holes 500 or as dummy holes 500 in form of blind holes which extend through a portion of a thickness of the plate 20. Importantly, any one of the dummy holes 500 provided in the general plate 20 may be used in any of the plates 50, 60, 50,60, 100, 200 described above. In other words, any one of the dummy holes 500 provided in the general plate 20 may be used in the first end plate 50, the second end plate, the first heat exchanger plates 100 and / or in the second heat exchanger plates 200 of the PCHEs of Figs. 1 and 4.

[0143] As illustrated in Fig. 10, the dummy holes 500 may have various shapes. For instance, the dummy holes 500 may have a semi-circular shape, a linear shape, an oblong shape, an oval shape, a zig-zag shape, a wavy shape, a cross shape, an elliptical shape a semi-elliptical shape, a curved shape or a combination thereof.

[0144] Further, as illustrated in the left part of Fig. 10, the dummy holes 500 may extend partially though a thickness of plate at hand, such as any of the plates 50, 60, 50,60, 100, 200 described above.

[0145] Furthermore, as illustrated in the right part of Fig. 10, the dummy holes 500 may extend completely though a thickness of plate at hand, such as any of the plates 50, 60, 50,60, 100, 200 described above.

[0146] Throughgoing dummy holes 500 and dummy holes 500 which extend partially though a thickness of plate may be combined at the same plate, such as any of the plates 50, 60, 50,60, 100, 200 described above.

[0147] The dummy holes 500 may extent to the perimeter of 26, 106, 206 of an associated plate 50, 60, 50,60, 100, 200 as illustrated in the lower left part of the plate 20 of Fig. 10.

[0148] Other shapes of dummy holes 500 than the ones depicted in Fig. 10 are conceivable. For instance, rectangular or square shaped dummy holes 500 may be used to advantage. Further, a dummy hole 500 may have shape which is a combination of the above-described and above depicted shapes. For instance, a dummy hole 500 may in part exhibit a cross shape and in part a liner shape.

[0149] Further, a width of dummy hole may vary. To this end, a dummy hole 500 which extends through a plate 50, 60, 50,60, 100, 200, may have a first mouth or opening of a first size and / or shape at a first major surface at an associated plate 50, 60, 50,60, 100, 200 while having a second mouth or opening of a second size and / or shape at a second opposite major surface at an associated plate 50, 60, 50,60, 100, 200. Thus, a dummy hole may taper or widen as seen a long the stacking direction S.

[0150] From the description above follows that, although various embodiments of the invention have been described and shown, the invention is not restricted thereto, but may also be embodied in other ways.

[0151] For instance, one or more dummy holes 500 may be provided in a single heat exchanger plate 100, 200 of a core 10.

[0152] For instance, one or more dummy holes 500 may be provided in one of the first and second end plates 50, 60.

[0153] For instance, one or more dummy holes 500 may be provided in some of the heat exchanger plates 100, 200 of a core 10.

[0154] For instance, one or more dummy holes 500 may be provided in some of the first heat exchanger plates 100 of a core 10.

[0155] For instance, one or more dummy holes 500 may be provided in some of the second heat exchanger plates 200 of a core 10.

[0156] For instance, one or more dummy holes 500 may be provided in some of the subplates 50:1, 50:2, 60:1 , 60:2, 60,50:1, 50:60:2 of an endplate 50, 60, 50,60.

[0157] For instance, one or more dummy holes 500 having a different designs or configurations may be provided at different portions of a plate 50, 60, 50,60, 100, 200 of a PCHE 1.

[0158] 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 printed circuit heat exchanger (1) comprising: a heat exchanger core (10), a first end plate (50), and a second end plate (60), wherein the heat exchanger core (10) comprises first heat exchanger plates (100) and second heat exchanger plates (200) alternatingly stacked onto each other in a stacking direction (S), and joined to each other, the heat exchanger core (10) being arranged between the first end plate (50) and the second end plate (60) as seen along the stacking direction (S), wherein each first heat exchanger plate (100) comprises a first heat exchange area (A1) comprising a number of first grooves (102), each first groove (102) forming a respective first passage (104) for a first media, the first passage (104) extending between a first inlet (104:1) configured to receive the first media, and a first outlet (104:2) configured to output the first media, wherein each second heat exchanger plate (200) comprises a second heat exchange area (A2) comprising a number of second grooves (202), each second groove (202) forming a respective second passage (204) for a second media, the second passage (204) extending between a second inlet (204:1) configured to receive the second media, and a second outlet (204:2) configured to output the second media, and wherein the printed circuit heat exchanger (1) is provided with one or more dummy holes (500) configured to reduce a thermal mass of the printed circuit heat exchanger (1), wherein each dummy (500) hole is provided in the first end plate (50), the second end plate (60), a first heat exchanger plate (100) or a second heat exchanger plate (200), and wherein each dummy hole (500) is disconnected from the first grooves (102) and the second grooves (202).

2. The printed heat exchanger (1) according to claim 1, wherein a dummy hole (500), of the one or more dummy holes (500), extends partially through a thickness of an associated plate (50, 60, 100, 200, 50,60, 20).

3. The printed circuit heat exchanger (1) according to claim 1 or 2, wherein a dummy hole (500), of the one or more dummy holes (500), has a depth within a rangecorresponding to 20-90%, preferably 25-80%, more preferably 30-50% of the thickness of an associated plate (50, 60, 100, 200, 50,60, 20).

4. The printed circuit heat exchanger (1) according to claim 1 , wherein a dummy hole (500), of the one or more dummy holes (500), extends completely through a thickness of an associated plate (50, 60, 100, 200, 50,60, 20).

5. The printed circuit heat exchanger (1) according to any one of the preceding claims, wherein a dummy hole (500), of the one or more dummy holes (500), has a circular shape, a semi-circular shape, a linear shape, a rectangular shape, a square shape, an oblong shape, an oval shape, a zig-zag shape, a wavy shape, a cross shape, an elliptical shape a semi-elliptical shape, or a curved shape.

6. The printed circuit heat exchanger (1) according to any one of the preceding claims, wherein any dummy hole (500), of the one or more dummy holes (500), of a pair of neighboring plates (50, 60, 100, 200, 50,60, 20) do not overlap each other as seen along the stacking direction (S).

7. The printed circuit heat exchanger (1) according to any one of the preceding claims, wherein the plates (50, 60, 100, 200, 50,60, 20) are formed by a metal comprising material, and wherein a dummy hole (500), of the one or more dummy holes (500), is formed by etching, drilling, laser cutting, water cutting, punching or milling into the metal comprising material.

8. The printed circuit heat exchanger (1) according to any one of the preceding claims, wherein a dummy hole (500), of the one or more dummy holes (500), is provided outside the first or the second heat exchange area (A1, A2) of an associated first or second heat exchanger plate (100, 200).

9. The printed circuit heat exchanger (1) according to any one of the preceding claims, wherein a dummy hole (500), of the one or more dummy holes (500), is provided between the first or the second heat exchange area (A1, A2) and the perimeter (106, 206) of an associated first or second heat exchanger plate (100, 200).

10. The printed circuit heat exchanger (1) according to any one of the preceding claims, wherein each first heat exchanger plate (100) and each second heat exchanger plate (200) are provided with a plurality of dummy holes (500).

11. The printed circuit heat exchanger according to any one of the preceding claims, wherein the first and / or second end plate (50, 60) is provided with a plurality of dummy holes (500).

12. The printed circuit heat exchanger (1) according claim 11 , wherein the plurality of dummy holes (500) is distributed over at least a major portion of an associated major surface of the first and / or second end plate (100, 200).

13. The printed circuit heat exchanger (1) according to any one of the preceding claims, wherein the first end plate (50) and / or the second end plate (60) is formed by a stack of subplates (50:1, 50:2, 60:1, 60:2) stacked onto each other in the stacking direction (S), and wherein one or more of the subplates (50:1, 50:2, 60:1, 60:2) is provided with a dummy hole (500), of the one or more dummy holes (500).

14. The printed circuit heat exchanger (1) according to claim 13, wherein the stack of subplates (50:1, 50:2, 60:1, 60:2) comprises one or more subplates (50:2, 60:2) provided with a dummy hole (500), of the one or more dummy holes (500), arranged between a pair of subplates (50:1, 60:1) void of dummy holes (500).

15. The printed circuit heat exchanger (1) according to claim 13, wherein the stack of subplates (50:1, 50:2, 60:1, 60:2) comprises two or more subplates (50:2, 60:2) provided with a plurality of dummy holes (500), of the one or more dummy holes (500), arranged between a pair of subplates (50:1, 60:1) void of dummy holes, and wherein the plurality of dummy holes (500) is distributed over at least a major portion of an associated major surface of the two or more subplates (50:2, 60:2).

16. The printed circuit heat exchanger (1) according to any one of the preceding claims, wherein each first and second heat exchanger plate (100, 200) comprises a pair of first port holes (150) and a pair of second port holes (160), wherein each first inlet (104:1) and each first outlet (104:2) communicate directly with a respective first port (150) hole of an associated first heat exchanger plate (100),wherein each second inlet (204:1) and each second outlet (204:2) communicate directly with a respective second port (160) hole of an associated second heat exchanger plate (200), wherein an end plate (50, 60), of the first end plate (50) and the second end plate (60), comprises a first opening (170) in fluid communication with a first port hole (150), and wherein an end plate (50, 60), of the first end plate (50) and the second end plate (60), comprises a second opening (180) in fluid communication with a second port hole (160).

17. The printed circuit heat exchanger (1) according to any one of claims 1-15, further comprising: first inlet and outlet headers (30, 35), and second inlet and outlet headers (40, 45), wherein each first inlet (104:1) communicates directly with a first inlet volume (V30) defined by the first inlet header (30) and the heat exchanger core (10), wherein each first outlet (104:2) communicates directly with a first outlet volume (V35) defined by the first outlet header (35) and the heat exchanger core (10), wherein each second inlet (204:1) communicates directly with a second inlet volume (V40) defined by the second inlet header (40) and the heat exchanger core (10), and wherein each second outlet (204:2) communicates directly with a second outlet volume (V45) defined by the second outlet header (45) and the heat exchanger core (10).

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