Refrigeration device and heat exchanger for a refrigeration device

Abstract

A heat exchanger for a refrigeration device comprises a multiplicity of fins having a plurality of first openings, which are arranged relative to one another, and a plurality of second openings, which are arranged relative to one another and are spaced from the first openings. The fins are spaced from one another such that the first openings and the second openings are in alignment. The heat exchanger also comprises a refrigerant tube which has a multiplicity of first tube sections and a multiplicity of arcuate second tube sections, wherein in each case two first tube sections interconnected by a second tube section extend through an associated first opening and through an associated second opening. Furthermore, the heat exchanger has a defrost heater having an elongate heating element which has a multiplicity of linear sections which are in thermally conductive contact with the first sections of the refrigerant tube and with the fins.

Description

[0001] Refrigeration unit and heat exchanger for a refrigeration unit

[0002] TECHNICAL AREA

[0003] The present invention relates to a refrigeration appliance, in particular a household refrigeration appliance such as a refrigerator, a freezer or a refrigerator-freezer combination, and a heat exchanger for a refrigeration appliance, in particular an evaporator.

[0004] STATE OF THE ART

[0005] Household refrigerators use a refrigerant circuit to extract heat from a storage chamber by evaporating refrigerant in an evaporator and releasing this heat to the environment through condensation of the refrigerant in a condenser. The evaporator is thermally coupled to the storage chamber. In so-called NoFrost appliances, the evaporator is located in an evaporator chamber that is fluidically connected to the storage chamber, with a fan circulating an airflow between the evaporator chamber and the storage chamber.

[0006] The evaporator is typically a heat exchanger consisting of a refrigerant tube and numerous fins thermally connected to the tube. The fins are arranged at predetermined intervals, defining flow channels through which the air circulated by the fan is transported. Due to the low temperatures at the evaporator and the potential moisture content of the air flowing between the fins, condensation forms on the evaporator, and over time, this usually leads to icing. Therefore, the evaporator is typically equipped with a defrost heater.

[0007] When defrosting the evaporator, it is desirable for heat to be directed into the evaporator by the defrost heater. US Patent 10,386,102 B2 describes an evaporator for a household refrigeration appliance, which has a multitude of fins, a refrigerant tube, and a defrost heater. The fins have initial cutouts through which the meandering refrigerant tube extends. The defrost heater comprises a heating tube for conveying a heating fluid and a heating element for heating the fluid. The heating tube, similar to the refrigerant tube, meanders and extends through secondary cutouts in the fins.

[0008] DE 10 2010 043 542 A1 describes a further evaporator for a household refrigeration appliance in which a heating element of a defrost heater and a refrigerant pipe are guided together through respective recesses in the fins of the evaporator. The recesses of the evaporator are enlarged in cross-section to accommodate the heating element and the refrigerant pipe, with the heating element being arranged between the refrigerant pipe and an inner circumference of the respective recess of the respective fin.

[0009] Another refrigerant evaporator with a defrost heater that runs through the same recesses in the fins as the refrigerant pipe is known from WO 2007 / 045677 A1.

[0010] SUMMARY OF THE INVENTION

[0011] One of the objectives of the present invention is to provide improved solutions for defrosting heat exchangers, in particular solutions that are advantageous in terms of manufacturing technology and at the same time facilitate targeted heat input into the heat exchanger.

[0012] This problem is solved according to the invention by a heat exchanger with the features of claim 1, a refrigerant circuit with the features of claim 8 and a refrigeration device with the features of claim 10.

[0013] Advantageous embodiments and further developments result from the dependent claims, which refer back to the independent claims, in conjunction with the description. According to a first aspect of the invention, a heat exchanger for a refrigeration unit comprises a plurality of fins with a plurality of first openings spaced apart from one another in a first direction, and a plurality of second openings spaced apart from one another in the first direction and from the first openings in a second direction. The fins are spaced apart from one another in a third direction, such that the first openings and the second openings of the fins are aligned in the third direction.The heat exchanger further comprises a refrigerant tube having a plurality of first tube sections extending in the third direction and a plurality of arc-shaped second tube sections, wherein two first tube sections extend through a respective first opening and through a respective second opening, and are connected to each other by a second tube section. In addition, the heat exchanger according to the invention has a defrost heater with a longitudinal heating element having a plurality of linear sections that are in thermally conductive contact with the first sections of the refrigerant tube and the fins.

[0014] According to the invention, it is provided that two linear sections of the heating element extend through a respective first opening and through a respective second opening, and the heating element has a plurality of connecting sections that each connect two linear sections together, so that the heating element extends continuously through both the first openings and the second openings.

[0015] According to a second aspect of the invention, a refrigerant circuit for a refrigeration appliance comprises an evaporator for evaporating refrigerant by absorbing heat, which is configured by a heat exchanger according to the first aspect of the invention; a condenser for condensing refrigerant by releasing heat, which is connected to the evaporator; a compressor, which is connected to the evaporator and the condenser and is configured to compress gaseous refrigerant coming from the evaporator and supply it to the condenser; and an expansion valve for refrigerant coming from the condenser, which is arranged between the condenser and the evaporator. According to a third aspect of the invention, a refrigeration appliance is provided, in particular a household refrigeration appliance such as a refrigerator, a freezer, or a fridge-freezer combination.The refrigeration unit comprises a storage compartment for holding refrigerated goods and a refrigerant circuit according to the second aspect of the invention, wherein the evaporator is thermally coupled to the storage compartment.

[0016] One of the ideas underlying the invention is to integrate a defrost heater with a continuous, uninterrupted heating element into a heat exchanger in such a way that the heating element runs in several rows of openings that are formed next to each other in the fins of the heat exchanger.

[0017] In particular, the fins have a first row of openings and a second row of openings, the first and second rows being adjacent to each other. A refrigerant tube extends meanderingly through the first and second openings, with two preferably linear first tube sections of the refrigerant tube extending through each of the first and second openings and being in thermal contact with the respective fin, e.g., by bearing against the inner circumference of the respective opening. For example, the refrigerant tube can run successively through the first openings, e.g., from one end of the first row to the other end of the first row, and then successively through the second openings, e.g., from the other end of the second row to the first end of the second row.

[0018] The louvers are spaced apart from each other, creating a gap between adjacent louvers. This gap serves as a flow channel, either to promote natural convection or to guide a forced airflow.

[0019] The defrost heater serves to supply heat to the refrigerant pipe and the fins in order to melt or defrost any ice that may form there. For this purpose, the defrost heater has a heating element that is in thermal contact with the refrigerant pipe and the fins. The defrost heater is designed to heat the heating element. The heating element is designed as a longitudinal, preferably rigid, element. The term "rigid" here can generally be understood as the property of a component or structure whereby, when supported at a point bearing at its center of gravity, the component or structure experiences no or only minimal deflection due to its own weight.

[0020] The heating element runs as a continuous, uninterrupted, meandering section through both the first and second openings. For this purpose, the heating element has linear sections and connecting sections. Each opening contains two linear sections, and these linear sections are in thermally conductive contact with the first pipe sections of the refrigerant tube and the respective fin. A connecting section joins each pair of linear sections.

[0021] One advantage of the invention is that the heating element and the refrigerant pipe run through the same openings in the fins. This eliminates the need for additional openings for the heating element, simplifying the manufacturing and design of the fins.

[0022] Because the linear sections of the heating element are connected by the connecting sections in such a way that the heating element extends continuously through both the first and second openings, the entire heat exchanger can be defrosted with a single heating element. This not only simplifies installation but also ensures a more uniform heat input into the heat exchanger.

[0023] According to some embodiments, two first linear sections of the heating element, extending through the same first opening of a respective lamella, and two second linear sections of the heating element, extending through the same second opening of a respective lamella, are each connected at a first end by a first connecting section, wherein a second connecting section connects a second end of one of the first linear sections to a second end of one of the second linear sections. The first connecting sections each connect the first or rear ends of two linear sections extending through the respective same opening. The second connecting sections each connect a first or front end of a linear section extending through a first opening to a linear section extending through a second opening.Accordingly, the heating element can alternately pass through the first and second openings. This offers the advantage that the second connecting sections can be easily routed past the second pipe sections of the refrigerant pipe, particularly when a first pipe section of a respective first or second opening is connected by a second pipe section to a first pipe section located in an adjacent opening in the first direction. Since the first connecting sections each connect two linear sections located in the same opening, the heating element as a whole can be easily inserted into the fin openings along the third direction.

[0024] According to some embodiments, the second end of one of the two first linear sections located in a respective first opening may be connected by a respective second connecting section to the second end of one of the two second linear sections located in a second opening adjacent in the second direction, and the second end of the other of the two first linear sections located in the respective first opening may be connected by a respective second connecting section to the second end of one of the two second linear sections located in a second opening adjacent in the first direction. Thus, the second connecting sections connect linear sections arranged in a zigzag pattern, connecting sections located in adjacent and diagonally located openings.This allows for easy installation of the second connecting sections.

[0025] According to some embodiments, the second connecting sections of the heating element and the second pipe sections of the refrigerant tube each project from a fin furthest in the third direction, with the second pipe sections of the refrigerant tube projecting further from the furthest fin in the third direction than the second connecting sections of the heating element. With respect to the third direction, the second connecting sections can thus be arranged between the second pipe sections and the furthest fin of the plurality of fins. Optionally, the second connecting sections can even be in contact with the furthest fin. Since the second connecting sections and the second pipe sections run separately or spaced apart, the second pipe sections can be easily provided with a holder without the need to adapt this holder to the connecting sections of the heating element.For example, a plate-shaped holder with a multitude of recesses can be provided into which the second pipe sections protrude and are held.

[0026] According to some embodiments, the two first linear sections within the respective first opening and the two linear sections within the respective second opening may be spaced apart in the first direction. This further facilitates the routing of the connecting sections, in particular the second connecting sections, in a space-saving and easy-to-assemble manner.

[0027] According to some embodiments, the first openings and the second openings may each be designed as elongated slots, and the first pipe sections of the refrigerant pipe may be arranged at opposite ends of the respective elongated slot with respect to its longitudinal extent, and may abut the inner circumference of the respective elongated slot. The elongated slots may optionally be inclined or angled relative to the first direction. For example, the angle between a longitudinal axis of the elongated slot and the first direction may be in a range between 15 degrees and 50 degrees.

[0028] According to some embodiments, the two linear sections of the heating element are arranged in a respective elongated hole, positioned between and in contact with the two first pipe sections of the refrigerant tube, relative to the longitudinal extent of the respective elongated hole. That is, each linear section of the heating element is not located between the inner circumference of the elongated hole and the outer circumference of the respective first pipe section, but rather rests against a section of the outer circumference of the respective first pipe section that faces the other first pipe section within the elongated hole. This allows the elongated hole to be of a constant width, particularly without requiring its shape to be specifically adapted to the position of the heating element. This further simplifies the manufacturing and assembly of the heat exchanger.

[0029] In some embodiments, the heating element may be designed as an electric heating element, in particular as a resistance heating element. In other embodiments, the heating element may be designed as a tube for conveying a fluid. For example, warm refrigerant can be passed through the heating element designed as a tube. This can help to increase the energy efficiency of a refrigerant circuit.

[0030] According to some embodiments, the refrigerant circuit may include a fan designed to generate an airflow that flows between the fins of the heat exchanger, e.g., through the space between adjacent fins. Optionally, the airflow can be directed along the first direction.

[0031] The features and advantages disclosed herein in connection with one aspect of the invention are also disclosed for the other aspect and vice versa.

[0032] BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The invention will now be explained with reference to the figures in the drawings. The figures show:

[0034] Fig. 1 shows a simplified, schematic sectional view of a refrigeration unit according to an embodiment of the invention;

[0035] Fig. 2 shows a schematic side view of a heat exchanger according to an embodiment of the invention;

[0036] Fig. 3 shows a front view of the heat transfer system shown in Fig. 2;

[0037] Fig. 4 shows a perspective view of the heat exchanger shown in Fig. 2; and

[0038] Fig. 5 is an exploded view of the heat exchanger shown in Fig. 2.

[0039] In the figures, the same reference symbols denote identical or functionally equivalent components, unless otherwise stated. DETAILED DESCRIPTION OF EXAMPLES OF EXECUTION

[0040] Fig. 1 shows an example of a refrigeration appliance 300 in the form of a refrigerator. The invention is described below by way of example with reference to the refrigerator shown in Fig. 1, but is not limited thereto. For example, the invention can also be used in other household refrigeration appliances, such as a freezer, a chest freezer, or a fridge-freezer combination, or generally in refrigeration appliances.

[0041] As schematically shown in Fig. 1, the refrigeration unit 300 has a housing 302, which defines a storage compartment 310 or a storage chamber for holding refrigerated goods, such as food, beverages, medicines, or the like. A separate machine room 312, distinct from the storage compartment 310, can optionally also be at least partially defined by the housing 302.

[0042] As further shown in Fig. 1, the refrigeration unit 300 has a refrigerant circuit 200. As shown schematically in Fig. 1, the refrigerant circuit 200 comprises an evaporator 210, a compressor 230, a condenser 220, and an expansion valve 240, e.g., in the form of a capillary. Optionally, the refrigerant circuit 200 also includes a fan 250.

[0043] The evaporator 210 is thermally coupled to the storage compartment 310 in order to extract heat from it by evaporating refrigerant. For example, as shown purely schematically and by way of example in Fig. 1, the evaporator 210 can be arranged in an evaporator chamber 315 which is fluidically connected to the storage compartment 310, and the fan 250 can be arranged and configured to circulate air between the evaporator chamber 315 and the storage compartment 310. The fan 250 thus draws warm air from the storage compartment 310, passes it through or over the evaporator 210, where the air transfers heat to the refrigerant located in the evaporator 210, and then expels the air back into the storage compartment 310.

[0044] The evaporator 210 has an outlet 212, which is connected to a suction port 231 of the compressor 230. The compressor 230 compresses the gaseous refrigerant coming from the evaporator 210 and feeds it via a pressure port 232 to an inlet 221 of the condenser 220. In the condenser 220, the refrigerant condenses, releasing heat to the surroundings. An outlet 222 of the condenser 220 is connected to an inlet 211 of the evaporator 210, with the expansion valve 240 arranged between the condenser 220 and the evaporator 210, causing the refrigerant to expand. As shown schematically in Fig. 1, the compressor 230 can, for example, be arranged in the machine room 312. The condenser 220 is also shown purely schematically in Fig. 1 and can be arranged, for example, on an outer wall of the body 302 or in the engine room 312.

[0045] The refrigerant circuit 200 is generally designed to extract heat from the storage compartment 310 by evaporating refrigerant and to release this heat to the environment by condensing refrigerant.

[0046] The evaporator 210 is shown schematically in Fig. 1 and is implemented by a heat exchanger 100 with a defrost heater 3. Due to the circulation of air between the storage compartment 310 and the evaporator chamber 315, ice or frost can form on the heat exchanger 100. This icing can be removed by means of the defrost heater 3.

[0047] Figures 2 to 5 show, purely by way of example, a heat exchanger 100 which can be used as an evaporator 210 in the refrigeration unit 300 shown by way of example in Figure 1. As can be clearly seen in particular in Figures 2, 4 and 5, the heat exchanger 100 has a plurality of fins 1, a refrigerant tube 2 and a defrost heater 3.

[0048] The lamellae 1 are generally realized as planar extending parts, for example as plates. For example, the lamellae 1 can have a rectangular perimeter, as shown by way of example in Fig. 3. As is further shown in particular in Fig. 3, each lamella 1 has a plurality of first openings 11 and a plurality of second openings 12. The first openings 11 are spaced apart from each other in a first direction X1. As can be seen in Fig. 2, the first openings 11 of each lamella 1 can be arranged in a first row along the first direction X1. The second openings 12 are also spaced apart from each other in the first direction X1. Furthermore, the second openings 12 are spaced apart from the first openings 11 in a second direction X2. The second direction X2 extends perpendicular or transverse to the first direction X1. As shown in Fig.As shown in Figure 3, the second openings 12 of each lamella 1 can be arranged in a second row along the first direction X1, with the second row being spaced apart from the first row in the second direction X2.

[0049] As further shown in Fig. 3, the first and second openings 11, 12 can each be designed as elongated slots. A longitudinal axis A11, A12 of the respective elongated slot can, for example, be angled relative to the first direction X1. For instance, the angle between the longitudinal axis A11, A12 of the elongated slot and the first direction X1 can be in a range between 15 degrees and 50 degrees.

[0050] As can be seen particularly in Fig. 2, the louvers 1 are spaced apart from each other in a third direction X3. The third direction X3 runs perpendicular or transverse to the first direction X1 and the second direction X2. As shown in Fig. 2, the spacing of the louvers 1 creates a gap between any two louvers 1 adjacent in the third direction X3, which can be used, for example, as a flow channel for guiding air through. The first openings 11 and the second openings 12 of the louvers 1, in particular of all louvers 1, are aligned in the third direction X3 (Fig. 3).

[0051] The lamellae 1 can be made of a metal material, such as an aluminum sheet, a copper sheet or a steel sheet.

[0052] The refrigerant pipe 2 serves to convey refrigerant and generally has a meandering course. In particular, the refrigerant pipe 2 has a plurality of first pipe sections 21, which can extend linearly, and a plurality of arc-shaped second pipe sections 22. A second pipe section 22 connects each pair of first pipe sections 21.

[0053] As can be seen in Figures 2, 4, and 5, two first pipe sections 21 extend through the first openings 11 aligned in the third direction X3. Similarly, two first pipe sections 21 extend through the first openings 11 aligned in the third direction X3. The two first pipe sections extending through a respective first opening 11 and a respective second opening 12 are connected to each other by a second pipe section 22. Optionally, one of the two first pipe sections 21 extending through a respective first opening 11 can be connected by a second pipe section 22 to one of the two first pipe sections 21 extending through an adjacent first opening 11, as shown in Figure 3 by the second pipe sections 22 depicted with dashed lines.Similarly, it can be provided that one of two first pipe sections 21, extending through a respective second opening 12, is connected by a second pipe section 22 to one of two first pipe sections 21, extending through an adjacent second opening 12, as illustrated in Fig. 3 by the second pipe sections 22 shown in dashed lines. Optionally, one of two first pipe sections 21, extending through a first opening 11 located at the end of the first row, can be connected by a second pipe section 22 to one of two first pipe sections 21, extending through a second opening 12 located at the end of the second row. That is, the refrigerant pipe 2 can optionally meander first through the first row of first openings 11 along the first direction X1 and then in the opposite direction through the second row of second openings 12.

[0054] If the openings 11, 12 are designed as elongated holes, the first pipe sections 21 of the refrigerant pipe 2 can be positioned at opposite ends of the respective elongated hole with respect to its longitudinal extent and bear against the inner circumference of the respective elongated hole. Figure 3 shows, purely by way of example, that the refrigerant pipe 2 has a circular cross-section and accordingly bears against semicircular end sections of the elongated hole.

[0055] The defrost heater 3 has a longitudinal heating element 30, which can be designed, for example, as an electric heating element, in particular as a resistance heating element, or as a tube 33 for conveying a fluid.

[0056] As shown by way of example in Figs. 2 to 5, the heating element 30 has a plurality of linear sections 31 and a plurality of connecting sections 32, wherein a connecting section 32 connects two linear sections 31 to each other. As can be seen particularly in Figs. 4 and 5, the heating element 30 extends as a longitudinal element continuously through the first openings 11 and the second openings 12 of the fins 1. As further shown in Figs. 2 to 5, two linear sections 31 each extend through a first opening 11, i.e., the first openings 11 aligned in the third direction X3. Likewise, two linear sections 31 each extend through a second opening 12, i.e., the second openings 12 aligned in the third direction X3.

[0057] The linear sections 31 of the heating element 30 are in thermally conductive contact with the first pipe sections 21 of the refrigerant pipe 2 and the fins 1. For example, it can be provided that in a respective elongated hole, the two linear sections 31 of the heating element 30 are arranged between the two first pipe sections 21 of the refrigerant pipe 2 with respect to the longitudinal extent of the respective elongated hole and bear against them. In addition, the linear sections can bear against the inner circumference of the elongated hole, e.g., against a side section of the inner circumference extending parallel to the longitudinal axis A11, A12 of the respective elongated hole, as shown by way of example in Fig. 3. This results in a large contact area between the refrigerant pipe 2 and the fin 1, as well as between the heating element 30, the refrigerant pipe, and the fin 1.Since the refrigerant pipe 2 rests directly against the end sections of the elongated hole, a more reliable mechanical fixation of the refrigerant pipe 2 relative to the fins 1 can also be achieved, which advantageously counteracts noise development in the event of vibrations.

[0058] As can be seen particularly in Figures 2 to 4, the heating element 30 can be arranged to meander alternately through first openings 11 and second openings 12. For example, the connecting sections 32 located at a first end or rear end of the linear sections 31 can run parallel to the second pipe sections 22 of the refrigerant pipe 2 positioned there, while the connecting sections located at a second or front end of the linear sections 31 extend between the first and second openings 11, 12, as shown by way of example in Figures 2 to 4.

[0059] The linear sections 31 of the heating element 30 extending through the first openings 11 are hereinafter referred to as first linear sections 31A. The linear sections 31 of the heating element 30 extending through the second openings 12 are hereinafter referred to as first linear sections 31B. As shown in Figures 2 to 4, it can be provided that two first linear sections 31A, extending through the same first opening 11 of a respective lamella 1, are connected at their first and rear ends, respectively, by a first connecting section 32A, and that two second linear sections 31B, extending through the same second opening 12 of a respective lamella 1, are also connected at their first and rear ends, respectively, by a first connecting section 32A. As explained above, the first connecting sections 32A can run parallel to the second pipe sections 22 located there, as shown e.g. in Fig.Figure 2 shows. Furthermore, it can be provided that a second connecting section 32B connects the second or front end of one of the first linear sections 31A with a second end of one of the second linear sections 31B.

[0060] For example, as shown in Fig. 3, the second end of one of the two first linear sections 31A located in a respective first opening 11 can be connected by a respective second connecting section 32B to the second end of one of the two second linear sections 31B located in a second opening 12 adjacent in the second direction X2. Furthermore, it can be provided that the second end of the other of the two first linear sections 31A located in the respective first opening 11 is connected by a respective second connecting section 32B to the second end of one of the two second linear sections 31B located in a second opening 12 adjacent in the first direction X1.

[0061] As shown by way of example in Fig. 3, the routing of the heating element 30 described above results in a kind of zigzag pattern of the heating element 30 between adjacent rows of openings 11, 12 in the second direction X2. An advantage of this routing of the heating element 30 is that the second connecting sections 32B do not run parallel to the second pipe sections 22 of the refrigerant pipe 2. This offers several advantages. On the one hand, it simplifies the installation of the heating element 30. It can be easily inserted into the openings 11, 12 of the fins 1 along the third direction X3, as indicated by arrow P5 in Fig. 5, without any space conflict with the refrigerant pipe 2. On the other hand, the second connecting sections 32B of the heating element 30 can be positioned closer to the fins 1 than the second pipe sections 22 of the refrigerant pipe 2, as can be seen particularly well in Fig. 2.This means that the second connecting sections 32B of the heating element 30 and the second pipe sections 22 of the refrigerant pipe 3 each project from a fin 1 in the third direction X3, with the second pipe sections 22 of the refrigerant pipe 2 projecting further from the fin 1 in the third direction X3 than the second connecting sections 32B of the heating element 30. This offers the advantage that a holder 6, which is shown purely schematically in Fig. 2, can be attached to the refrigerant pipe 2 without any space conflict with the heating element 30.

[0062] Although the present invention has been explained above by way of example embodiments, it is not limited to these, but can be modified in many ways. In particular, combinations of the preceding embodiments are also conceivable.

[0063] REFERENCE MARK

[0064] 1 fin 2 refrigerant pipe

[0065] 3 defrost heaters, 6 holders

[0066] 11 first openings 12 second openings 21 first pipe sections

[0067] 22 second pipe section 30 heating element 30 longitudinal heating element 31 linear sections of the heating element 31A first linear sections 31B second linear sections 32 connecting sections of the heating element 32A first connecting sections 32B second connecting sections 100 heat exchanger 200 refrigerant circuit 210 evaporator 211 evaporator inlet 212 evaporator outlet 220 condenser 221 condenser inlet 222 condenser outlet

[0068] 230 Compressor 231 Suction port 232 Pressure port 240 Throttle 250 Fan 300 Refrigeration unit 302 Housing 310 Storage compartment 5 312 Machine room

[0069] 315 Evaporator chamber

Claims

PATENT CLAIMS 1. Heat exchanger (100) for a refrigerating appliance (300), in particular for a domestic refrigerating appliance, comprising: a plurality of fins (1) with a plurality of first openings (11) spaced apart from one another in a first direction (X1), and a plurality of second openings (12) spaced apart from one another in the first direction (X1) and from the first openings (11) in a second direction (X2), wherein the fins (1) are spaced apart from one another in a third direction (X3) such that the first openings (11) and the second openings (12) are aligned in the third direction (X3); a refrigerant pipe (2) comprising a plurality of first pipe sections (21) extending in the third direction (X3) and a plurality of arcuate second pipe sections (22), wherein a respective first opening (11) and through a respective second opening (12) two first pipe sections (21) extend, which are connected to each other by a second pipe section (22); and a defrost heater (3) with a longitudinal heating element (30) having a plurality of linear sections (31, 31A, 31B) which are in thermally conductive contact with the first sections (21) of the refrigerant pipe (2) and the fins (1); characterized in that through a respective first opening (11) and through a respective second opening (12) each of the heating element (30) extends through two linear sections (31 , 31 A, 31 B), and the heating element (30) has a plurality of connecting sections (32, 32A, 32B) which each connect two linear sections (31 , 31 A, 31 B) together, so that the heating element extends continuously through both the first openings (11) and the second openings (12).

2. Heat exchanger (100) according to claim 1, wherein two first linear sections (31A) of the heating element (30) extending through the same first opening (11) of a respective fin (1), and two second linear sections (31B) of the Heating elements (30) extending through the same second opening (12) of a respective lamella (1) are each connected at a first end by a first connecting section (32A), and wherein a second connecting section (32B) connects a second end of one of the first linear sections (31A) to a second end of one of the second linear sections (31B).

3. Heat exchanger (100) according to claim 2, wherein the second end of one of the two first linear sections (31A) located in a respective first opening (11) is connected by a respective second connecting section (32B) to the second end of one of the two second linear sections (31B) located in a second opening (12) adjacent in the second direction (X2), and wherein the second end of the other of the two first linear sections (31A) located in the respective first opening (11) is connected by a respective second connecting section (32B) to the second end of one of the two second linear sections (31B) located in a second opening (12) adjacent in the first direction (X1).

4. Heat exchanger (100) according to claim 2 or 3, wherein the second connecting sections (32B) of the heating element (30) and the second pipe sections (22) of the refrigerant pipe (3) each project from a last fin (1) in the third direction (X3), wherein the second pipe sections (22) of the refrigerant pipe (2) project further from the last fin (1) in the third direction (X3) than the second connecting sections (32B) of the heating element (30).

5. Heat exchanger (100) according to one of claims 2 to 4, wherein the two first linear sections (31A) are spaced apart within the respective first opening (11) and the two linear sections (31) are spaced apart within the respective second opening (12) in the first direction (X1).

6. Heat exchanger (100) according to one of the preceding claims, wherein the first openings (11) and the second openings (12) are each designed as elongated holes, and the first pipe sections (21) of the refrigerant pipe (2) are connected at opposite ends with respect to the longitudinal extent of the respective elongated hole. of the respective elongated hole and are located on the inner circumference of the respective elongated hole, and wherein in a respective elongated hole the two linear sections (31) of the heating element (30) are arranged between the two first pipe sections (21) of the refrigerant pipe (2) with respect to the longitudinal extent of the respective elongated hole and are located on them.

7. Heat exchanger (100) according to one of the preceding claims, wherein the heating element (30) is designed as an electric heating element, in particular as a resistance heating element or as a tube (33) for passing a fluid through it.

8. Refrigerant circuit (200) for a refrigeration appliance (300), in particular for a household refrigeration appliance, comprising: an evaporator (210) for evaporating refrigerant by absorbing heat, which is configured by a heat exchanger (100) according to one of the preceding claims; a condenser (220) for condensing refrigerant by releasing heat, which is connected to the evaporator (210); a compressor (230) which is connected to the evaporator (210) and the condenser (220) and is configured to compress gaseous refrigerant coming from the evaporator (210) and to supply it to the condenser (220); and an expansion valve (240) for expanding refrigerant coming from the condenser (220), which is arranged between the condenser (220) and the evaporator (210).

9. Refrigerant circuit (200) according to claim 8, further comprising: a fan (250) which is designed to generate an airflow which flows between the fins (1) of the heat exchanger (100).

10. Refrigeration appliance (300), in particular a household refrigeration appliance, comprising: a storage compartment (310) for receiving refrigerated goods; and a refrigerant circuit (200) according to claim 8 or 9, wherein the evaporator (210) is thermally coupled to the storage compartment (310).

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