Heat exchanger for a compressed air refrigeration dryer

Abstract

A heat exchanger (120) configured as an evaporator for a compression refrigeration machine (110) for treating compressed air for a compressed air refrigeration dryer (100), wherein the heat exchanger (120) has a heat transfer block (222) comprising compressed air passages (323) shaped to guide the compressed air through the heat transfer block (222) and refrigerant passages (325) shaped to guide a refrigerant through the heat transfer block (222), wherein the heat transfer block (222) is constructed and shaped from baffles (224) between the passages (323, 325, 327), fins (226) in the passages (323, 325, 327) and boundary elements (228) as side walls of the passages (323, 325, 327). to effect heat transfer between compressed air guided through the compressed air passages (323) and refrigerant guided through the refrigerant passages (325), wherein the heat transfer block (222) includes at least one reducing element (228; 550;880) which is shaped and arranged with respect to the refrigerant passages (325) to make the area and / or volume available for contact with refrigerant in the refrigerant passages (325) smaller than the area and / or volume available for contact with compressed air in the compressed air passages (323).;

Description

[0001] The present invention relates to a heat exchanger, a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer with such a heat exchanger, and a compressed air refrigeration dryer with such a compression refrigeration machine.

[0002] Today, so-called safety refrigerants are commonly used in compression refrigeration systems. Due to their chemical composition, these are non-flammable and non-toxic. However, under Regulation (EU) 2024 / 573 on fluorinated greenhouse gases and the potential regulation of refrigerants through a revision of the REACH Regulation, fluorinated refrigerants, such as the components of refrigerant R-513A, are being increasingly restricted or even banned by legislation. This necessitates the use of natural refrigerants like R-290 (propane). R-290 is a flammable refrigerant.

[0003] In the plate-and-bar design commonly used for compressed air refrigerant heat exchangers, where a heat exchanger block is constructed from baffles, fins, and bars, the number and size of the necessary refrigerant passages—and thus the internal volume—depend primarily on the required compressed air passages. Since a refrigerated dryer should have the lowest possible differential pressure on the compressed air side and therefore features generously sized compressed air passages, the refrigerant passages can often be significantly larger than necessary for heat transfer. Adjusting the height of the passages, for example, is only possible in manufacturer-specified increments or, due to the design of such heat exchangers, also depends on the dimensions of the compressed air passages.These design-related restrictions can, for example, lead to an oversizing of the refrigerant passage, resulting in a higher refrigerant charge in the refrigeration circuit of the system than necessary.

[0004] Against this background, the present invention provides an improved heat exchanger, an improved compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer, and an improved compressed air refrigeration dryer according to the main claims. Advantageous embodiments are described in the dependent claims and the following description.

[0005] According to embodiments, a safe heat exchanger, optionally also suitable for flammable refrigerants, can be provided for use as an evaporator for a compression refrigeration machine for a compressed air refrigeration dryer. In the heat exchanger according to embodiments, the volume of a refrigerant path within the heat exchanger can be minimized, which is also advantageous for the safety concept of the system when handling, for example, flammable refrigerants.

[0006] A heat exchanger is presented, configured as an evaporator for a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer, wherein the heat exchanger has a heat transfer block comprising compressed air passages shaped to guide the compressed air through the heat transfer block and refrigerant passages shaped to guide a refrigerant through the heat transfer block, wherein the heat transfer block is constructed of baffles between the passages, fins in the passages, and boundary elements as side walls of the passages, and is shaped to effect heat transfer between the compressed air guided through the compressed air passages and the refrigerant guided through the refrigerant passages, wherein the heat transfer block has at least one reducing element shaped and arranged with respect to the refrigerant passages.to make the area and / or volume available for contact with refrigerant in the refrigerant passages smaller than the area and / or volume available for contact with compressed air in the compressed air passages.

[0007] The heat exchanger can also be referred to as a heat transfer device or a heat exchanger. The compressed air treatment can include drying by cooling, thus combining drying and cooling. The heat transfer block can be made of aluminum, for example, with the baffles, strips, and optionally the fins also being made of aluminum. The heat transfer block can be constructed by brazing and, additionally or alternatively, welding. In this case, the baffles, strips, and optionally the fins can be brazed and, additionally or alternatively, welded together. The refrigerant can be a flammable refrigerant. One possible design for such a heat exchanger, which functions as an evaporator, is a brazed aluminum heat exchanger.For example, the so-called plate-and-bar design can be used, in which the heat exchanger block can be constructed from baffles, fins, and bars. In a special form of such aluminum block heat exchangers, frames made of flat material can be used instead of bars. The at least one reducing element can be shaped and positioned relative to the refrigerant passages to make the area available for contact with refrigerant in at least one section of the refrigerant passages smaller than the area available for contact with compressed air in at least one section of the compressed air passages. The at least one reducing element can be located in or on at least one of the refrigerant passages. The area available for contact with refrigerant can be understood here, in particular, as the area that is contacted by the refrigerant at the baffles.Any reduction in surface area due to the fins may be excluded from this. The reduction of the surface area available for contact with refrigerant can only be achieved by the at least one reducing element. The surface area available for contact with compressed air can be understood here, in particular, as the surface that is contacted by the compressed air at the separating plates. Any reduction in surface area due to the fins may be excluded from this.

[0008] When designing a heat exchanger, it's possible to determine the required refrigerant-side heat transfer area to achieve the desired cooling capacity and the necessary flow cross-sections of the passages to ensure a permissible differential pressure is not exceeded. Based on this information, the passages can be designed so that only the required heat transfer area is exposed to refrigerant. Consequently, at least one pressure-reducing element can be dimensioned accordingly. A heat exchanger design can prioritize heat transfer capacity, heat transfer area, and the permissible differential pressure. The required passage volume is determined by adhering to these requirements.By arranging the reducing elements, a refrigerant passage can be made proportionally smaller than a compressed air passage. This allows for a minimum heat transfer surface area of ​​the refrigerant passage at a defined pressure drop, and / or to make the usable area of ​​the refrigerant passage smaller than that of the compressed air passage, thus achieving the minimum required heat transfer surface area. The heat transfer surface area can therefore be reduced, consequently reducing the volume, which requires only a smaller refrigerant charge. The charge volume can result from the structural conditions and the minimum required heat transfer surface area.

[0009] According to one embodiment, the at least one reducing element can be shaped and arranged with respect to the refrigerant passages in order to make the area available for contact with refrigerant in the refrigerant passages smaller than the area available for contact with compressed air in the compressed air passages.

[0010] It is advantageous if the area available for contact with refrigerant and / or the available volume in the refrigerant passages is at least 10 percent, 20 percent, 30 percent, 40 percent or 50 percent smaller than the area available for contact with compressed air and / or the available volume in the compressed air passages.

[0011] The reducing element can also be designed and positioned to at least partially fill a free space located outside a finned area in at least one of the refrigerant passages. In this case, the reducing element can function as a volume displacement body. Such an embodiment offers the advantage that the required refrigerant volume in the heat exchanger can be minimized in a structurally simple manner without additional components. By completely filling the unused areas, the aluminum used can advantageously improve heat conduction within the heat exchanger block. This allows heat released on the compressed air side in parallel passages in these areas to be transferred more effectively to the refrigerant. Furthermore, the installed mass can store sensible heat.

[0012] Furthermore, the at least one reducing element can be shaped and arranged to separate at least a portion of a free space located outside a finned area in at least one of the refrigerant passages from a flow cross-section of the refrigerant passages available to the refrigerant. Such a free space can optionally be at least partially filled with additional fins or other structures to increase strength. This embodiment offers the advantage that material accumulation can be avoided, thus reducing the required heat input during the soldering process.

[0013] It is also advantageous if the part of the free space separated from the flow cross-section is vented to the environment of the heat exchanger.

[0014] According to one embodiment, the at least one reducing element can have at least one of the limiting elements that limits at least one of the refrigerant passages. The at least one limiting element of the limiting elements, which functions as a reducing element and limits at least one of the refrigerant passages, can be designed as a strip or a frame. Such an embodiment offers the advantage that the heat transfer surface required in the heat exchanger on the refrigerant side can be minimized in a structurally simple manner without additional components.

[0015] The at least one reducing element can also include at least one contoured sheet metal unit formed in one or more parts. A portion of at least one of the refrigerant passages can run through the at least one contoured sheet metal unit. The contoured sheet metal unit can delimit at least one of the refrigerant passages. The contoured sheet metal unit can be attached to a section of at least one of the refrigerant passages. Such an embodiment offers the advantage of achieving a simple and reliable minimization of the required heat transfer surface area in the heat exchanger.

[0016] The at least one contour sheet unit can have a flow channel for the refrigerant. The flow channel can be bounded by wall sections of the contour sheet unit. Such an embodiment offers the advantage that the required heat transfer surface can be easily minimized by appropriately dimensioning the wall sections that bound the flow channel.

[0017] Optionally, at least a section of the flow channel can also be fitted with fins. This design offers the advantage of improved heat transfer to the refrigerant and enhanced strength of the heat exchanger block.

[0018] Furthermore, the at least one contour sheet unit can have nested sections, and the flow channel can be meandering. The flow channel can be at least partially bounded by the nested sections. The flow cross-section of the meandering flow channel can vary along its length, for example, depending on the state of matter of the refrigerant, to achieve a constant flow velocity. Such an embodiment offers the advantage that minimizing the required area and / or volume of the refrigerant passage can be easily achieved by appropriately dimensioning the nested sections that bound the flow channel, and that heat transfer into the refrigerant through the meandering flow channel can also be improved.

[0019] Furthermore, at least one contour sheet unit can have at least one cavity vented to the surrounding area of ​​the heat exchanger. Such recessed contour sheets of the contour sheet unit offer the advantage that material accumulation can be avoided, thus reducing the required heat input during the brazing process.

[0020] According to one embodiment, the at least one reducing element can have at least one additional element that is attached in at least one of the refrigerant passages. Additionally or alternatively, the at least one additional element can be arranged so that the refrigerant flows around it at least partially and / or be shaped to predefine a refrigerant flow path. The at least one additional element can be shaped to make the refrigerant flow path meandering, for example. The at least one additional element can be shaped as an insert, insert, or the like. Such an embodiment offers the advantage that a structurally simple minimization of the required refrigerant volume in the heat exchanger can be achieved.Filling the unused areas with at least one additional element can advantageously achieve improved heat conduction within the heat exchanger block, for example, through the use of aluminum. This allows heat released by the compressed air in parallel passages within these areas to be transferred more effectively to the refrigerant. Furthermore, the mass of the at least one additional element can store sensible heat.

[0021] According to one embodiment, the heat transfer block can include separation passages arranged between the refrigerant passages and the compressed air passages. These separation passages can be designed as empty passages, allowing heat flow from the compressed air to the refrigerant and otherwise vented to the atmosphere. Alternatively, the separation passages can be filled with a medium and optionally also be permeated by that medium. The medium can be, for example, a phase change material (PCM), another latent heat storage medium, or a heat transfer fluid. Such an embodiment offers the advantage that a safe heat exchanger can be implemented, particularly for flammable refrigerants.

[0022] A compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer is also presented, wherein the compression refrigeration machine comprises an embodiment of a heat exchanger mentioned herein as an evaporator, a refrigerant compressor, a condenser and a fan.

[0023] The compression refrigeration machine can be used to cool compressed air, which is generally saturated with water vapor. In the evaporator, the refrigerant extracts heat from the moist compressed air, evaporating in the process. This vapor is then drawn in and compressed by the refrigerant compressor. At this higher pressure level, the heat from the refrigerant is transferred to the cooling air via the condenser. A fan creates or forces the flow of this cooling air, or convection.

[0024] The compression refrigeration machine can also include an additional heat exchanger. The cooled compressed air can be passed through this heat exchanger after the evaporator and used to pre-cool the incoming warm compressed air. This allows the dried compressed air to be reheated and results in a lower relative humidity than the incoming compressed air.

[0025] Furthermore, a compressed air refrigeration dryer is presented, which comprises an embodiment of a compression refrigeration machine mentioned herein.

[0026] In a compressed air refrigeration dryer, the physical relationship between temperature and water vapor content of the compressed air can be used to dehumidify the compressed air by cooling it and causing the water vapor to condense. A compression refrigeration unit is used to cool the compressed air, which is generally saturated with water vapor.

[0027] The invention is explained in more detail by way of example with reference to the accompanying drawings. These show: Fig. 1 a schematic representation of a compressed air refrigeration dryer with a compression refrigeration machine according to an exemplary embodiment; Fig. 2 a schematic partial representation of a heat exchanger according to an exemplary embodiment; Fig. 3A a schematic partial representation of a heat exchanger according to an exemplary embodiment; Fig. 3B a schematic partial representation of a heat exchanger according to an exemplary embodiment; Fig. 4 a schematic partial representation of a heat exchanger according to an exemplary embodiment; Fig. 5 a schematic partial representation of a heat exchanger according to an exemplary embodiment; Fig. 6 a schematic partial representation of a heat exchanger according to an exemplary embodiment; Fig. 7 a schematic partial representation of a heat exchanger according to an exemplary embodiment; Fig. 8 a schematic partial representation of a heat exchanger according to an exemplary embodiment; Fig. 9 a schematic partial representation of a heat exchanger according to an exemplary embodiment; Fig. 10 a schematic partial representation of a heat exchanger according to an exemplary embodiment; Fig. 11 a schematic partial representation of a heat exchanger according to an exemplary embodiment; Fig. 12 a schematic partial representation of a heat exchanger according to an exemplary embodiment; Fig. 13 a schematic partial representation of a heat exchanger according to an exemplary embodiment; and Fig. 14 a schematic partial representation of a heat exchanger according to an exemplary embodiment.

[0028] In the following description of preferred embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and having a similar effect, without repeating these elements.

[0029] Fig. Figure 1 shows a schematic representation of a compressed air refrigeration dryer 100 with a compression refrigeration unit 110 according to an exemplary embodiment. Only the compression refrigeration unit 110 of the compressed air refrigeration dryer 100 is shown by way of example. The compression refrigeration unit 110 is designed to treat compressed air for the compressed air refrigeration dryer 100, more precisely to cool and dry it, or to dry it by cooling.

[0030] The compression refrigeration machine 110 comprises a refrigerant compressor 112, a condenser 114, a fan 116, and a heat exchanger 120 acting as an evaporator. The compression refrigeration machine 110 is used to cool compressed air, which is generally saturated with water vapor. A refrigerant extracts heat from the moist compressed air in the heat exchanger 120, which acts as an evaporator, thereby evaporating. The evaporated air is then drawn in and compressed by the refrigerant compressor 112. At this higher pressure level, the heat from the refrigerant is transferred to the cooling air via the condenser 114. A flow of the cooling air, or convection, is created or enforced by the fan 116. The compression refrigeration machine 110 also includes a throttling device 118, such as a capillary tube, at least one throttle valve, etc.

[0031] According to one embodiment, the compressed air refrigeration dryer 100 or the compression refrigeration machine 110 can also include a further heat exchanger, in particular an air-to-air heat exchanger for pre-cooling. The cooled compressed air can be passed through the further heat exchanger after the heat exchanger 120, which acts as an evaporator, and used to pre-cool the incoming warm compressed air. This allows the dried compressed air to be reheated and results in a lower relative moisture content than the incoming compressed air.

[0032] The heat exchanger 120, which functions as an evaporator, will be discussed in more detail with reference to the following figures.

[0033] Fig. Figure 2 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The heat exchanger 120 is designed as an evaporator for a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer. The heat exchanger 120 corresponds to or is similar to the heat exchanger functioning as an evaporator for a compression refrigeration machine from [reference to be added]. Fig. 1. Thus, the heat exchanger 120 is used as an evaporator for the compression refrigeration machine. Fig. 1 or a similar compression refrigeration machine.

[0034] The heat exchanger 120 comprises a heat transfer block 222. A section A of the heat transfer block 222 is also shown separately enlarged in the illustration. According to the embodiment shown here, the heat exchanger 120 is constructed from baffles 224, fins 226, and strips 228 as boundary elements. Thus, the heat exchanger 120 is constructed according to a so-called plate-and-bar design. One possible design of the heat exchanger 120, which functions as an evaporator, can include brazed aluminum heat exchanger units.

[0035] Fig. Figure 3A shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The heat exchanger 120 is designed as an evaporator for a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer. The heat exchanger 120 corresponds to or is similar to the heat exchanger functioning as an evaporator for a compression refrigeration machine from [reference to be added]. Fig. 1. Thus, the heat exchanger 120 is used as an evaporator for the compression refrigeration machine. Fig. 1 or a similar compression refrigeration machine. The heat exchanger 120 comprises a heat transfer block 222 and an external section outside the heat transfer block 222. The heat transfer block 222 corresponds to or is similar to that of Fig. 2. In the illustration, a section B of the heat transfer block 222 is shown separately enlarged.

[0036] The heat transfer block 222 comprises compressed air passages 323, which are shaped to guide the compressed air through the heat transfer block 222, and furthermore refrigerant passages 325, which are shaped to guide a refrigerant, optionally a flammable refrigerant, through the heat transfer block 222. With further reference to Fig. 2. The separating plates are arranged between the passages 323 and 325, with the fins arranged in the passages 323 and 325 and the limiting elements or strips serving as side walls of the passages 323 and 325. The heat transfer block 222 is designed to effect heat transfer between compressed air guided through the compressed air passages 323 and refrigerant guided through the refrigerant passages 325. The heat transfer takes place within the heat transfer block 222.

[0037] Fig. Figure 3B shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The heat exchanger 120 corresponds to the heat exchanger from Fig. 3A except that the heat transfer block 222 also includes separation passages 327 arranged between the refrigerant passages 325 and the compressed air passages 323. With further reference to Fig. 2. The separating plates are arranged between the passages 323, 325, 327, wherein the fins are arranged in the passages 323, 325, 327 and the limiting elements or strips are used as side walls of the passages 323, 325, 327. The separating passages 327 can be arranged on both sides of the refrigerant passages 325, or only one separating passage 327 can be arranged as a PCM passage on one side. In the illustration, a section C of the heat transfer block 222 is also shown separately enlarged.

[0038] In other words, according to one embodiment, the heat exchanger 120 is composed of at least three different passages 323, 325, 327: There are compressed air passages 323 through which the compressed air to be dried flows, refrigerant passages 325 through which the refrigerant flows, and there are separation passages 327 or safety passages. To prevent leakage between the compressed air and the refrigerant in the heat transfer block 222 or block area, each refrigerant passage 325 is surrounded on both sides by a separation passage 327. The separation passages 327 can be empty passages that merely ensure the heat flow from the compressed air to the refrigerant and are otherwise vented to the atmosphere. However, it is also possible to use the separation passages 327 for a different medium. One possibility is to fill these separation passages 327 with a phase change material (PCM) or to flow a heat transfer fluid through them.Apart from the fact that each refrigerant passage 325 is to be surrounded by a separation passage 327, the arrangement of the passages 323, 325, 327 is freely selectable. For example, for reasons of symmetry, several adjacent compressed air passages 323 can be implemented, or for reasons of minimum charge quantity, several adjacent separation passages 327, safety passages, or PCM passages can be implemented.

[0039] Fig. Figure 4 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The heat exchanger 120 is designed as an evaporator or as an evaporator and air-to-air heat exchanger for a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer. According to one exemplary embodiment, the evaporator and air-to-air heat exchanger or precooler are combined in a single unit. The heat exchanger 120 corresponds to or is similar to the heat exchanger functioning as an evaporator for a compression refrigeration machine from [reference to relevant figure]. Fig. 1, Fig. 2 and / or Fig. 3. The heat exchanger 120 is designed as an evaporator for the compression refrigeration machine. Fig. 1 or a similar compression refrigeration machine.

[0040] In the representation of Fig. Figure 4 is part of the heat transfer block, more precisely two finned passages, here exemplified by a compressed air passage 323 and a refrigerant passage 325, boundary elements 228 or strips, and part of an outer section with first means 430 and second means 440 are shown. In particular, a compressed air outlet 423 and a refrigerant passage 325 are shown. The outer section of the heat exchanger 120, arranged outside the heat transfer block, comprises first means 430 for distributing, collecting, and / or redirecting the compressed air from and into compressed air passages 323 of the heat transfer block and second means 440 for distributing, collecting, and / or redirecting the refrigerant from and into refrigerant passages 325 of the heat transfer block.According to one embodiment, the first means 430 comprise at least one distribution box, at least one collection box and / or at least one deflection box for the compressed air and the second means 440 comprise at least one distribution box, at least one collection box and / or at least one deflection box for the refrigerant.

[0041] Further features of the heat exchanger 120 will be discussed in more detail with reference to the following figures.

[0042] Fig. Figure 5 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The heat exchanger 120 is designed as an evaporator for a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer. The heat exchanger 120 is designed as an evaporator for the compression refrigeration machine made of Fig. 1 or a similar compression refrigeration machine. The heat exchanger 120 corresponds to or is similar to the heat exchanger functioning as an evaporator for a compression refrigeration machine from one of the figures described above.

[0043] In the representation of Fig. Figure 5 shows a part of the heat transfer block, here by way of example a compressed air passage 323 and a refrigerant passage 325, limiting elements 228 or strips, and part of an outer section with first means 430 and second means 440. Furthermore, by way of example, only one reducing element of the heat transfer block is shown, which, according to the embodiment shown here, is designed as a contour sheet unit 550. The reducing element, wherein the heat exchanger 120 has at least one such element, is shaped and arranged with respect to the refrigerant passage 325 in order to make the area and / or volume available for contact with refrigerant in the refrigerant passage 325 smaller than the area and / or volume available for contact with compressed air in the section of the compressed air passage 323 running parallel to the refrigerant passage 325.

[0044] The contour sheet unit 550 is formed in one piece or in multiple pieces. A portion of the refrigerant passage 325 runs through the contour sheet unit 550, which here functions as a reducing element. The contour sheet unit 550, acting as a reducing element, limits the refrigerant passage 325. The contour sheet unit 550 encompasses and / or forms a flow channel for the refrigerant. The flow channel is, for example, filled with fins. The contour sheet unit 550 has several, in this case three, nested sections. This results in a meandering flow channel formed by the contour sheet unit 550. This is particularly noticeable in comparison with Fig. Figure 4 shows that at least one reducing element, i.e., the contour sheet unit 550, is shaped and arranged to at least partially fill a free space located outside a finned area in the refrigerant passage 325. For this purpose, the nested sections have dimensions to at least partially fill the free space. The part of the refrigerant passage 325 shown is formed by the contour sheet unit 550, which functions as a reducing element.

[0045] Fig. Figure 6 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The heat exchanger 120 is designed as an evaporator for a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer. The heat exchanger 120 is designed as an evaporator for the compression refrigeration machine made of Fig. 1 or a similar compression refrigeration machine. The heat exchanger 120 and the illustration correspond to the heat exchanger and the illustration from Fig. 5 except that the refrigerant passage 325 is also limited by limiting elements 228 or strips, and the contour sheet unit 550, which functions as a reducing element, is surrounded on at least some of its sides by such limiting elements 228. In other words, the contour sheet unit 550, which functions as a reducing element, is inserted into the refrigerant passage 325, which is also limited by limiting elements 228 or strips.

[0046] An open area 660 is arranged, for example, between the contour sheet unit 550 and the limiting elements 228 or strips that define the refrigerant passage 325. According to the embodiment shown here, the flow channel formed by the contour sheet unit 550 is also filled with the fins. However, for example, a guide area 655, which is shaped to direct the refrigerant only to a specific location, here to one of the second means 440, can be designed without fins.

[0047] Fig. Figure 7 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The heat exchanger 120 is designed as an evaporator for a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer. The heat exchanger 120 is designed as an evaporator for the compression refrigeration machine made of Fig. 1 or a similar compression refrigeration machine. The heat exchanger 120 and the illustration correspond to the heat exchanger and the illustration from Fig. 6 except that the contour sheet unit 550, which acts as a reducing element, is shaped differently.

[0048] According to the embodiment shown here, the reducing element, designed as a contour sheet unit 550, is shaped and arranged to separate at least a portion of a free space located outside a finned area in the refrigerant passage from a flow cross-section of the refrigerant passage 325 available to the refrigerant. The flow cross-section available to the refrigerant corresponds to the flow channel formed by the contour sheet unit 550. Optionally, the portion of the free space separated from the flow cross-section is vented to the vicinity of the heat exchanger 120. For this purpose, the contour sheet unit 550, functioning as a reducing element, has at least one cavity 770 vented to the vicinity of the heat exchanger 120. According to the embodiment shown here, the contour sheet unit 550 has several such cavities 770.

[0049] Fig. Figure 8 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The heat exchanger 120 is designed as an evaporator for a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer. The heat exchanger 120 is designed as an evaporator for the compression refrigeration machine made of Fig. 1 or a similar compression refrigeration machine. The heat exchanger 120 and the illustration correspond to or resemble the heat exchanger and illustration from one of the figures described above.

[0050] In the representation of Fig. Figure 8 is part of the heat transfer block, shown here by way of example as a compressed air passage 323, a refrigerant passage 325, and limiting elements 228 or strips. Furthermore, reducing elements of the heat transfer block are shown, which, according to the embodiment presented here, have additional elements 880 and limiting elements 228 that define the refrigerant passage 325. The reducing elements are shaped and arranged with respect to the refrigerant passage 325 to make the area and / or volume available for contact with refrigerant in the refrigerant passage 325 smaller than the area and / or volume available for contact with compressed air in the compressed air passage 323. The additional elements 880, here by way of example only two, are attached in the refrigerant passage 325. For example, the additional elements 880 are arranged so that the refrigerant can flow around them, at least partially.According to the embodiment shown here, the additional elements 880 together with the limiting element 228 are also shaped, for example, to modify a flow path of the refrigerant in a predefined manner, here to make it meandering or to guide the refrigerant in a meandering manner.

[0051] Fig. Figure 9 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The heat exchanger 120 is designed as an evaporator for a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer. The heat exchanger 120 corresponds to or is similar to the heat exchanger functioning as an evaporator for a compression refrigeration machine from one of the figures described above. The heat exchanger 120 is designed as an evaporator for the compression refrigeration machine from Fig. 1 or a similar compression refrigeration machine. The one in Fig. The part of the heat exchanger 120 shown in section 9 resembles a part of the one in Fig. 4 heat exchangers shown, wherein in Fig. Figure 9 shows a compressed air passage 323, limiting elements 228 designed as strips, and a second means 440. See also the illustration in Fig. 14.

[0052] Fig. Figure 10 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The heat exchanger 120 is designed as an evaporator for a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer. The heat exchanger 120 corresponds to or is similar to the heat exchanger functioning as an evaporator for a compression refrigeration machine from one of the figures described above. The heat exchanger 120 is designed as an evaporator for the compression refrigeration machine from Fig. 1 or a similar compression refrigeration machine. The one in Fig. The part of the heat exchanger 120 shown in section 10 resembles a part of the one in Fig. 4 heat exchanger shown and corresponds to the one in Fig. 9 shown part of the heat exchanger, except that in Fig. 10 a refrigerant passage 325, reducing elements which have limiting elements 228 designed as strips and first means 430 are shown.

[0053] According to the embodiment shown here, the limiting elements 228, which function as reducing elements and are designed as strips, are shaped and arranged with respect to the refrigerant passage 325 in order to make the area and / or volume available for contact with refrigerant in the refrigerant passage 325 smaller than the area and / or volume available for contact with compressed air in a compressed air passage such as the one shown in Fig. 9 shown in the compressed air passage. The reducing elements are shaped and arranged, for example, to at least partially fill a free space located outside a finned area in the refrigerant passage 325. The limiting elements 228, designed as strips, have a greater wall thickness than the limiting elements of the compressed air passage, which are also designed as strips. Fig. 9 up.

[0054] In other words, the limiting elements 228, which function as reducing elements and are designed as strips, result in a reduced refrigerant passage 325. The refrigerant passage 325 is reduced by at least 10%, 20%, 30%, 40% or 50% compared to a compressed air passage such as the compressed air passage made of Fig. 9 reduced or reduced in area. In other words, in the refrigerant passage 325, with respect to a heat transfer surface, there is a reduction of at least 10%, preferably at least 20%, particularly preferably at least 30%, further preferably at least 40% and finally preferably at least 50% compared to a compressed air passage. Fig. 9 provided. The limiting elements 228 in the refrigerant passage 325, which function as reducing elements and are designed as strips, are designed, for example, such that in a section plane parallel to the refrigerant flow less area and / or volume is available for contact with refrigerant than in compressed air passages arranged parallel to the refrigerant passage 325 where area and / or volume is available for contact with compressed air.

[0055] Fig. Figure 11 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The in Fig. The part of the heat exchanger 120 shown in section 11 corresponds to the one in Fig. 10 depicted part of the heat exchanger, except that in Fig. 11. The limiting elements 228, which function as reducing elements and are designed as strips, are shaped differently and differently from one another. One of the limiting elements 228, shown on the left in the illustration, has an angled or curved profile. This separates a section 1170 of the refrigerant passage 325 from a flow cross-section available to the refrigerant. Section 1170 is vented to the outside or to the surroundings of the heat exchanger 120. Furthermore, one of the limiting elements 228, shown on the right in the illustration, has different wall thicknesses in different sections and acts as a solid body in one section. The design of the limiting elements 228 shown here is merely exemplary and can be modified as desired according to another embodiment, for example, with only one of the two shown in Fig. The 11 variants of the boundary elements 228 shown can be realized.

[0056] Fig. Figure 12 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The in Fig. The part of the heat exchanger 12 shown in Figure 12 corresponds to the one in Figure 12. Fig. 10 and / or Fig. 11 depicted part of the heat exchanger, with the exception that in Fig. 12 A reducing element is provided, which has a limiting element 228 designed as a frame. The heat exchanger 120 is thus designed as a frame. The limiting element 228, designed as a frame and functioning here as a reducing element, has different wall thicknesses along both long sides in order to reduce the heat transfer surface of the refrigerant passage 325.

[0057] Fig. Figure 13 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The in Fig. The part of the heat exchanger 120 shown in section 13 corresponds to the one in Fig. 12 depicted part of the heat exchanger, except that in Fig. 13 the limiting element 228, designed as a frame and also acting as a reducing element, has identical or similar wall thicknesses along both long sides in order to reduce the heat transfer surface of the refrigerant passage 325.

[0058] Fig. Figure 14 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The in Fig. The part of the heat exchanger 120 shown in section 14 corresponds to the one in Fig. 5 depicted part of the heat exchanger, in particular with the exception that in the section plane of Fig. Figure 14 shows the compressed air passage 323 in the air-to-air heat exchanger section of the heat exchanger 120 and in the air-to-refrigerant heat exchanger section of the heat exchanger 120, and illustrates a subdivision of this entire compressed air passage 323 into a compressed air passage 323a in the air-to-air heat exchanger section and a compressed air passage 323b in the air-to-refrigerant heat exchanger section. Furthermore, a compressed air path is symbolically illustrated by arrows, whereby the re-entry of the compressed air into the air-to-air heat exchanger section occurs in a different section plane than the one shown here. Furthermore, in Fig. Figure 14 shows the limiting elements 228, first means 430, second means 440, a compressed air outlet 423 and a compressed air inlet 1123, which function as reducing elements and are designed as strips.

[0059] For comparison with the surface area available for contact with refrigerant in the refrigerant passage of heat exchanger 120, only the compressed air passage 323b located in the refrigerant-compressed air heat exchanger section is to be used. In other words, the reduced (contact) area of ​​the refrigerant is to be compared only with the surface area available for contact with compressed air in the compressed air passage 323b in the air-refrigerant heat exchanger section. Here too, any area occupied by fins is to be ignored.

[0060] With reference to the figures described above, features of exemplary embodiments are summarized again below and briefly presented in other words.

[0061] Contour plates, which form the boundary of the refrigerant passage 325, are dimensioned such that only the flow channel cross-section necessary for the required heat transfer and the required refrigerant-side differential pressure is present to accommodate the fins 226. The remaining area is filled by the contour plates, thus reducing the volume on the refrigerant side. Contour plates here refer in particular to boundary elements 228 and / or the contour plate unit 550 and / or the additional elements 880.

[0062] To reduce the refrigerant charge of the entire system, particularly the heat exchanger 120, the refrigerant-side volume of the evaporator is kept as small as possible, according to the exemplary embodiments. To achieve this with appropriately generously sized compressed air passages 323, parts of the refrigerant passages 325 are filled by using such contoured plates. This can be done either by completely filling the unused areas or by creating recessed, externally vented areas or cavities 770. Inserting plates as additional elements 880 into the area is also conceivable.

[0063] If the heat exchanger 120 is constructed from strips as limiting elements 228, correspondingly large, especially wide, strips or sheets can be inserted into the refrigerant passage 325 to reduce the volume as desired. These sheets, like the additional elements 880, can be completely surrounded by the flow or also serve to guide the refrigerant along a defined path – for example, a meander.

[0064] Contour plates, such as the contour plate unit 550, can also be used in the refrigerant sections, taking over the function of the normally inserted strips or limiting elements 228. The contour plate unit 550 can be designed so that the entire space is available as an evaporator, resulting in a meandering refrigerant flow or enabling a geometrically free-form refrigerant flow path. To transfer heat to the refrigerant and to ensure strength, the areas within the contour plate or contour plate unit 550 are filled with fins. Whether certain areas, such as the guide area 655, which are only intended to direct the refrigerant to a specific location, are designed without fins can be decided depending on the required strength.Should such material accumulations not be possible or practical due to the manufacturing process, the contour sheets of the contour sheet unit 550 can also be designed to form cavities 770 that are open to the outside. Depending on the size of the cavities 770, these can optionally be provided with additional lamellae to increase strength.

[0065] The embodiments described and shown in the figures are only examples. Different embodiments can be combined completely or with respect to individual features. An embodiment can also be supplemented by features from another embodiment.

[0066] If an embodiment includes an “and / or” connection between a first feature and a second feature, this can be interpreted as meaning that the embodiment according to one embodiment has both the first feature and the second feature, and according to another embodiment either only the first feature or only the second feature. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 2024 / 573

[0002]

Claims

[1] Heat exchanger (120) configured as an evaporator for a compression refrigeration machine (110) for treating compressed air for a compressed air refrigeration dryer (100), wherein the heat exchanger (120) has a heat transfer block (222) comprising compressed air passages (323) shaped to guide the compressed air through the heat transfer block (222) and refrigerant passages (325) shaped to guide a refrigerant through the heat transfer block (222), wherein the heat transfer block (222) is constructed and shaped from baffles (224) between the passages (323, 325, 327), fins (226) in the passages (323, 325, 327) and boundary elements (228) as side walls of the passages (323, 325, 327). is to effect heat transfer between compressed air guided through the compressed air passages (323) and refrigerant guided through the refrigerant passages (325), wherein the heat transfer block (222) includes at least one reducing element (228; 550;880) which is shaped and arranged with respect to the refrigerant passages (325) to make the area and / or volume available for contact with refrigerant in the refrigerant passages (325) smaller than the area and / or volume available for contact with compressed air in the compressed air passages (323).; [2] Heat exchanger (120) according to claim 1, wherein the at least one reducing element (228; 550; 880) is shaped and arranged with respect to the refrigerant passages (325) to make an area available for contact with refrigerant in the refrigerant passages (325) smaller than an area available for contact with compressed air in the compressed air passages (323). [3] Heat exchanger (120) according to claim 1, wherein the area available for contact with refrigerant and / or the available volume in the refrigerant passages (325) is at least 10 percent, 20 percent, 30 percent, 40 percent or 50 percent smaller than the area available for contact with compressed air and / or the available volume in the compressed air passages (323). [4] Heat exchanger (120) according to one of the preceding claims, wherein the at least one reducing element (228; 550; 880) is shaped and arranged to at least partially fill a free space arranged outside a finned area fitted with the fins (226) in at least one of the refrigerant passages (325). [5] Heat exchanger (120) according to one of the preceding claims, wherein the at least one reducing element (228; 550; 880) is shaped and arranged to separate at least a part of a free space arranged outside a fin area equipped with the fins (226) in at least one of the refrigerant passages (325) from a flow cross-section of the refrigerant passages (325) available for the refrigerant. [6] Heat exchanger (120) according to claim 5, wherein the part of the free space separated from the flow cross-section is vented to an environment of the heat exchanger (120). [7] Heat exchanger (120) according to one of the preceding claims, wherein the at least one reducing element has at least one of the limiting elements (228) that limits at least one of the refrigerant passages (325). [8] Heat exchanger (120) according to one of the preceding claims, wherein the at least one reducing element has at least one contour sheet unit (550) formed in one piece or in more pieces, wherein a part of at least one of the refrigerant passages (325) passes through the at least one contour sheet unit (550). [9] Heat exchanger (120) according to claim 8, wherein the at least one contour sheet unit (550) has a flow channel for the refrigerant. [10] Heat exchanger (120) according to claim 9, wherein at least a partial section of the flow channel is equipped with the fins (226). [11] Heat exchanger (120) according to one of claims 9 to 10, wherein the at least one contour sheet unit (550) has nested sections and the flow channel is meandering. [12] Heat exchanger (120) according to one of claims 8 to 11, wherein the at least one contour sheet unit (550) has at least one cavity (770) vented to an environment of the heat exchanger (120). [13] Heat exchanger (120) according to one of the preceding claims, wherein the at least one reducing element has at least one additional element (880) which is attached in at least one of the refrigerant passages (325), and / or wherein the at least one additional element (880) is arranged to be at least partially surrounded by the refrigerant and / or is shaped to predefine a flow path of the refrigerant. [14] Heat exchanger (120) according to one of the preceding claims, wherein the heat transfer block (222) comprises separation passages (327) arranged between the refrigerant passages (325) and the compressed air passages (323). [15] Compression refrigeration machine (110) for treating compressed air for a compressed air refrigeration dryer (100), wherein the compression refrigeration machine (110) comprises a heat exchanger (120) according to one of the preceding claims as an evaporator, a refrigerant compressor (112), a condenser (114) and a fan (116). [16] Compressed air refrigeration dryer (100) with a compression refrigeration machine (110) according to claim 15.

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