Evaporator and refrigerator

Abstract

Evaporators and refrigerators are provided that can reduce the problem of frost clogging the air passage and improve heat exchange efficiency. The evaporator (4) includes: at least one refrigerant pipe (10), which is a plurality of flat pipe sections (11) that are arranged in a first direction (D1) for a plurality of refrigerant flow paths (14) and connected in the direction of refrigerant flow; a plurality of flat slit fins (20) or straight fins (28) that are installed on the pipe sections (11) in such a way that the pipe sections (11) pass through and are arranged with gaps in the extension direction of the pipe sections (11); and an inlet pipe (7) connected to the upstream end of the refrigerant pipe (10) and an outlet pipe (8) connected to the downstream end of the refrigerant pipe (10).

Description

Technical Field

[0001] This disclosure relates to evaporators and refrigerators. Background Technology

[0002] In refrigerators, an evaporator (or heat exchanger) is used for cooling the interior. In the evaporator described in Patent Document 1, the connecting pipes are configured to connect to a refrigerant inlet. The connecting pipes consist of a first pipe, a second pipe, and an inlet pipe. Multiple fins are provided in the evaporator. The connecting pipes pass through the notches of the plate-shaped fins. The heat exchanger described in Patent Document 2 is a finned and tubular heat exchanger. In this heat exchanger, the straight sections of the tubes also penetrate the plate-shaped fins.

[0003] Patent Document 1: International Publication No. 2023 / 005652

[0004] Patent Document 2: Japanese Patent Application Publication No. 2020-101318

[0005] When applying the aforementioned finned and tubular heat exchanger to a refrigerator, there is a problem of frost buildup blocking the airflow. Consequently, the space between the fins cannot be reduced, resulting in insufficient heat exchange capacity. Furthermore, increasing the size of the heat exchanger reduces the refrigerator's storage volume.

[0006] Besides the heat exchangers mentioned above, microchannel heat exchangers are also known, for example. In this type of heat exchanger, corrugated fins are adjacent to flat tubes with multiple refrigerant flow paths. High integration increases the thermal conductivity on the air side and also increases the heat exchange area on the refrigerant side, thereby increasing the heat flux. However, in the porous flat tubes used in typical microchannel heat exchangers, the aperture of the refrigerant flow paths is small, which can increase the pressure loss when the refrigerant passes through. Therefore, it is difficult to use it as a heat exchanger (evaporator) for refrigerators using liquid refrigerants. Furthermore, there is also the problem of frost buildup blocking the airflow due to the narrow space between the fins. Utility Model Content

[0007] This disclosure describes an evaporator and a refrigerator that can reduce the problem of frost clogging the air passage and improve heat exchange efficiency.

[0008] [1] An evaporator according to one aspect of the present disclosure comprises: at least one refrigerant tube, which is formed by having a plurality of flat tube sections that arrange a plurality of refrigerant flow paths in a first direction and connecting the tube sections in the refrigerant flow direction; a plurality of flat plate fins installed on the tube sections in such a way that the tube sections pass through and are arranged with gaps in the extension direction of the tube sections orthogonal to the first direction; and an inlet pipe connected to the upstream end of the refrigerant tube and an outlet pipe connected to the downstream end of the refrigerant tube.

[0009] According to the evaporator in [1], from the viewpoint of heat exchange efficiency, a flat tube section with multiple refrigerant flow paths arranged in a row is more advantageous than existing finned and tubular heat exchangers. Furthermore, the structure of an evaporator with refrigerant tubes composed of such a flat tube section and flat fins is less prone to frost buildup that blocks the airflow. Therefore, according to this evaporator, the problem of frost buildup blocking the airflow can be reduced, and heat exchange efficiency can be improved.

[0010] [2] Alternatively, in the evaporator of [1] described above, the refrigerant tube has an overall U-shaped structure in which two tube sections are opposed to each other in a second direction orthogonal to both the first and extending directions, and a bend is provided between the two tube sections. In this case, the bend is equivalent to a foldback section of the refrigerant tube. The inlet end and outlet end of the refrigerant tube can be arranged on the same side (at one side end face). This arrangement is advantageous in terms of heat exchange efficiency and miniaturization of the evaporator.

[0011] [3] Alternatively, in the evaporator of [1] or [2] above, each fin has a flat plate portion with at least one elongated hole through which the refrigerant tube passes, and a flange portion protruding relative to the flat plate portion is provided at the periphery of the elongated hole portion. According to this structure, good contact between the refrigerant tube portion and the fin is ensured, and contact thermal resistance is reduced.

[0012] [4] Alternatively, in any of the evaporators described in [1] to [3] above, each fin has: a flat plate portion having at least one elongated hole through which the tube portion passes; and a protruding piece formed by cutting off a portion of the flat plate portion, excluding the connecting edge, relative to the flat plate portion and obliquely lifting that portion from the flat plate portion. According to this structure, the heat exchange efficiency with air is improved by the protruding piece. The protruding piece is cantilevered (connected to the flat plate portion only by the connecting edge, with the other parts open), therefore, condensation components are less likely to accumulate, and the protruding piece also undergoes elastic deformation when frosting occurs, thus preventing damage to the slits.

[0013] [5] Alternatively, in the evaporator of [4] above, each fin has: the aforementioned protruding fin, which is formed by obliquely raising a portion of the flat plate portion on one side of the flat plate portion; and another protruding fin, which is formed by cutting off a portion of another part of the flat plate portion, excluding the connecting end edge, relative to the flat plate portion and obliquely raising that other part of the flat plate portion on the other side of the flat plate portion. The protruding fin and the other protruding fin protrude alternately on one side and the other side of the flat plate portion, thereby improving the turbulence effect of the airflow.

[0014] [6] Alternatively, in the evaporator of [5] above, the plate portion and other portions are each rectangles extending longer in a second direction orthogonal to both the first and extending directions, and the ratio (z1 / z2) of the size (z1) of each of the protruding pieces in the first direction to the spacing (z2) between the protruding pieces in the first direction is a value in the range of 0.3 or more and 0.5 or less. According to this structure, it is possible to suppress the excessively dense arrangement of the protruding pieces. Excessively dense arrangement of protruding pieces, for example, causes a decrease in airflow due to increased pressure loss. The decrease in airflow leads to a decrease in heat flux. Furthermore, during de-icing, ice easily hooks onto the protruding pieces, causing ice residue. With the above-described appropriate arrangement (density), good heat exchange can be achieved.

[0015] [7] Alternatively, in any of the above [4] to [6] evaporators, the protrusion height of the protruding piece from the flat plate can be arbitrarily set within the range of 5 mm or less. According to this structure, the protrusion height can be appropriately selected from different heights such as 1 mm, 2 mm and 3 mm, and therefore, performance adjustment is easy.

[0016] [8] Alternatively, in the evaporator of any of [1] to [7] above, multiple refrigerant pipes are provided, which are stacked in a first direction. A main connector, consisting of a flat, rectangular first connecting portion and a cylindrical second connecting portion connected to the first connecting portion, is installed at the inlet or outlet end of each refrigerant pipe. The multiple refrigerant pipes are connected in series through these main connectors. The main connector allows for easy connection between the upper and lower refrigerant pipes. Existing connectors cause significant pressure drops, but the main connector disclosed herein effectively reduces flow resistance within the pipe section. This reduces pressure drop and contributes to improved energy efficiency of the refrigerator.

[0017] [9] Alternatively, in any of the above [1] to [8] evaporators, the ratio of the length of the tube section to the width of the tube section in the first direction, i.e., the aspect ratio, is a value in the range of 4 or more and 10 or less. According to this structure, the above-mentioned effects (increased heat exchange ratio and prevention of frost adhesion, etc.) are appropriately achieved.

[0018]

[10] Alternatively, in any of the above [1] to [9] evaporators, the number of refrigerant flow paths provided in the pipe section is in the range of 3 or more and 10 or less. According to this structure, the flow resistance of the refrigerant can be suppressed, and good heat exchange can be achieved.

[0019] A refrigerator equipped with an evaporator possessing any of the aforementioned features can improve heat exchange efficiency and reduce energy consumption. Further energy consumption reduction can be achieved by extending the defrost interval. Furthermore, frost buildup is less likely to clog airflow, and heat exchange efficiency can be ensured even with a smaller evaporator than existing ones. Therefore, evaporator miniaturization is possible. As a result, the storage capacity of refrigerator 1 can be increased.

[0020] According to this disclosure, the problem of frost clogging the air passage can be reduced, and heat exchange efficiency can be improved. Attached Figure Description

[0021] Figure 1 This is a diagram showing an evaporator and a refrigerator equipped with the evaporator according to one embodiment of the present disclosure.

[0022] Figure 2 This is a perspective view of an evaporator according to one embodiment.

[0023] Figure 3 It is an exploded perspective view showing the refrigerant pipe and the multiple fins installed on the pipe section.

[0024] Figure 4 It is a diagram showing the arrangement of refrigerant flow paths at the pipe section.

[0025] Figure 5 This is a three-dimensional view of the fins.

[0026] Figure 6 (a) is the front view of the fin. Figure 6 (b) is a side view of the fin.

[0027] Figure 7 This is a 3D view of the main connector.

[0028] Figure 8 Is with Figure 5 The diagram shows three-dimensional views of different types of fins.

[0029] Explanation of reference numerals in the attached figures

[0030] 1...Refrigerator; 2...Shell; 4...Evaporator; 6...Compressor; 7...Inlet piping; 8...Outlet piping; 10...Refrigerant pipe; 11...Pipe section; 13...Bend; 14...Refrigerant flow path; 20...Slit fin; 21...Plate section; 22...Elongated hole section; 25...Flange section; 26...Protruding piece; 26b...Connecting edge; 27...Protruding piece (another type of protruding piece); 27b...Connecting edge; 28...Straight fin; 30...Main connector; 31...First connecting part; 32...Second connecting part; D1...First direction; D2...Second direction; D3...Third direction (extension direction). Detailed Implementation

[0031] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Furthermore, in the description of the drawings, the same reference numerals are used for the same elements, and repeated descriptions are omitted. In some drawings, three-dimensional orthogonal axes are indicated together for ease of explanation. In this specification, unless otherwise specified, the terms "upstream" and "downstream" are used based on the direction of refrigerant flow.

[0032] like Figure 1 As shown, the refrigerator 1 of this embodiment has a door 3 and multiple drawers 5 at the front of the casing 2. The interior space of the casing 2 is used as a storage compartment for refrigeration or freezing. The arrangement of the door 3 and drawers 5 of the refrigerator 1, and the purpose of each space divided within the casing 2 (refrigeration or freezing, etc.) can be appropriately set and changed. The refrigerator 1 includes, for example, an evaporator 4 located at an appropriate position at the rear of the casing 2 and a compressor 6 located, for example, at the lower part of the casing 2. These structures are used for a refrigeration cycle that maintains each storage space of the refrigerator 1 at a low temperature. In the refrigerator 1, for example, a suitable non-CFC liquid refrigerant (such as isobutane (R-600a)) is used. The type of refrigerant is not particularly limited.

[0033] The refrigeration cycle of refrigerator 1 is a well-known method, with refrigerant flowing within a predetermined circulation path. Although not illustrated, refrigerator 1 is equipped with necessary devices such as a condenser and an expansion valve. Evaporator 4 absorbs heat from the air, causing the refrigerant flowing in the refrigerant path to evaporate. Compressor 6 compresses the refrigerant, converting it into a high-temperature, high-pressure vapor (gas). The high-temperature, high-pressure refrigerant gas is converted into a low-temperature liquid by heat dissipation through the condenser. The liquid refrigerant is depressurized in a capillary tube and passes through the evaporator again. In refrigerator 1, the capillary tube acts as the expansion valve in the refrigeration cycle. Evaporator 4 absorbs heat from the surrounding air (endothermic action), thereby generating low-temperature cold air. Evaporator 4 is also called a cooler.

[0034] Overall, the evaporator 4 is rectangular parallelepiped in shape. The evaporator 4 is configured such that when the evaporator 4 is considered as a simple rectangular parallelepiped, the shortest side of the evaporator 4 (the portion extending along the second direction D2 described below) is aligned with the front-to-back direction of the refrigerator 1.

[0035] Reference Figure 2 The following figures provide a detailed explanation of the structure of evaporator 4. For example... Figure 2 As shown, the evaporator 4 has a structure in which five refrigerant pipes 10 are stacked in a first direction D1. The stacking direction of the refrigerant pipes 10, i.e., the first direction D1, is the same as that of the refrigerator 1 (see reference). Figure 1 The evaporator 4 is vertically positioned within the refrigerator 1. Furthermore, "stacked" simply refers to the vertical relationship between one refrigerant pipe 10 and another; it does not necessarily mean that the two refrigerant pipes 10 are in contact. Alternatively, the two refrigerant pipes 10 may be close to each other in the first direction D1, with a small gap between them.

[0036] From another perspective, the evaporator 4 is a heat exchanger. The number of refrigerant pipes 10 in the evaporator 4 is not particularly limited. The five refrigerant pipes 10 illustrated in this embodiment all have a common structure (identical structure). The five refrigerant pipes 10 are arranged vertically in the same orientation. The internal refrigerant flow paths of the five refrigerant pipes 10 are connected in series from the inlet pipe 7 to the outlet pipe 8 (generally from top to bottom). The five refrigerant pipes 10 are fixed together by suitable fixing units (not shown), forming a single unit.

[0037] Figure 3 This is an exploded perspective view showing the refrigerant pipe 10 and the multiple fins installed on the pipe section 11 of the refrigerant pipe 10. Figure 3 Only one of the five refrigerant pipes 10 described above is shown. The refrigerant pipe 10 has a structure in which two (or a pair) flat pipe portions 11 extending along a third third direction (extension direction) D3 are positioned opposite each other in a second direction D2, spaced apart by a predetermined distance. The two pipe portions 11 have identical structures and are configured to be parallel to each other.

[0038] The two tube sections 11 are opposite each other in the second direction D2. (As shown in the image) Figure 2 With the components shown separately, multiple refrigerant flow paths 14 are exposed at one end 11a of each of the two pipe sections 11 in the third direction D3. Figure 4 As shown, in the pipe section 11, a plurality of (e.g., eight) refrigerant flow paths 14 are arranged along the first direction D1. Each refrigerant flow path 14 is parallel (in other words, along the direction D1). Figure 4The refrigerant pipe 10 extends perpendicularly to the third direction (D3) of the paper. A U-shaped bend 13 is provided between the other ends 11b, 11b of the two pipe sections 11 in the third direction (D3). A straight, flat pipe containing multiple refrigerant flow paths 14 is bent at its center to form the bend 13. Thus, a refrigerant pipe 10 with two parallel pipe sections 11 is formed. Therefore, the refrigerant pipe 10 has a U-shaped structure overall.

[0039] The refrigerant pipe 10 is made of, for example, a molded aluminum. However, the material of the refrigerant pipe 10 is not limited to aluminum, as long as it is a material with excellent thermal conductivity; it can also be stainless steel, copper with high thermal conductivity, or titanium with high corrosion resistance, etc.

[0040] like Figure 3 and Figure 4 As shown, the opposing inner surfaces 11d of the two tube sections 11 form flat surfaces extending in the first direction D1 and the second direction D2. A space 15 is formed between the pair of inner surfaces 11d, allowing air to pass through in the first direction D1. Furthermore, the outer surfaces 11c of each of the two tube sections 11 also form flat surfaces extending in the first direction D1 and the second direction D2.

[0041] like Figure 4 As shown, the ratio of the length E of the pipe section 11 in the first direction D1 to the width F of the pipe section 11, i.e., the aspect ratio, is, a value in the range of 4 or more and 10 or less. The number of refrigerant flow paths 14 provided in each pipe section 11 is in the range of 3 or more and 10 or less (eight in an embodiment). Each pipe section 11 has a predetermined length E (also called height) in the first direction D1 and extends in the third direction D3, and has a relatively thin width F in the second direction D2. The distance between a pair of pipe sections 11 can also be more than 5 times the width F.

[0042] It can also be said that the U-shaped flat refrigerant pipe 10 is a new part in the evaporator 4 of the refrigerator 1 (or in the heat exchanger assembly).

[0043] return Figure 2The evaporator 4, from top to bottom, includes a first refrigerant pipe 10A, a second refrigerant pipe 10B, a third refrigerant pipe 10C, a fourth refrigerant pipe 10D, and a fifth refrigerant pipe 10E. The fourth refrigerant pipe 10D is located above the fifth refrigerant pipe 10E. The third refrigerant pipe 10C is located above the fourth refrigerant pipe 10D. The second refrigerant pipe 10B is located above the third refrigerant pipe 10C. The first refrigerant pipe 10A is located above the second refrigerant pipe 10B. An inlet pipe 7 is connected to the upstream end 11a of the first refrigerant pipe 10A via a general connector 30 (described below). An outlet pipe 8 is connected to the downstream end 11a of the fifth refrigerant pipe 10E via a general connector 30 (described below). The inlet pipe 7 is connected to the aforementioned capillary tube. The outlet pipe 8 is connected to the compressor 6. A accumulator 36 is provided midway through the outlet pipe 8 to prevent liquid refrigerant from returning to the compressor 6.

[0044] like Figure 3 and Figure 7 As shown, a main connector 30, consisting of a flat, rectangular first connecting portion 31 and an annular second connecting portion 32 connected to the first connecting portion 31, is installed at one end 11a of each refrigerant pipe 10. The main connector 30 is made of, for example, aluminum alloy and is joined by welding the same end 11a. A total of 10 main connectors 30 are provided for the five refrigerant pipes 10. Two adjacent main connectors 30 (along the first direction D1) are connected by upper and lower connecting pipes 38, which are made of U-shaped (or C-shaped) round tubes. The upper and lower connecting pipes 38 are also made of aluminum or aluminum alloy and are joined to the main connector 30, for example, by brazing. In this way, multiple refrigerant pipes 10 are connected in series by multiple main connectors 30.

[0045] like Figure 7 As shown, an opening 33 of the same shape and size as one end 11a is formed on the connecting end face 31a of the first connecting portion 31 of the main connector 30. The interiors of the first connecting portion 31 and the second connecting portion 32 are simply cavities, without any protrusions, partitions, or the like that obstruct the flow of refrigerant. As a result, the pressure drop of the refrigerant flowing from the refrigerant pipe 10 to the other refrigerant pipes 10 is reduced.

[0046] In evaporator 4, from Figure 4When viewed in the directions shown (the same reference is used throughout this paragraph), in the first refrigerant pipe 10A, the left end 11a corresponds to the upstream end (connected to the inlet pipe 7), and the right end 11a corresponds to the downstream end. In the second refrigerant pipe 10B, the right end 11a corresponds to the upstream end (connected to the right end 11a of the first refrigerant pipe 10A), and the left end 11a corresponds to the downstream end. In the third refrigerant pipe 10C, the left end 11a corresponds to the upstream end (connected to the left end 11a of the second refrigerant pipe 10B), and the right end 11a corresponds to the downstream end. In the fourth refrigerant pipe 10D, the right end 11a corresponds to the upstream end (connected to the right end 11a of the third refrigerant pipe 10C), and the left end 11a corresponds to the downstream end. Furthermore, in the fifth refrigerant pipe 10E, the left end 11a corresponds to the upstream end (connected to the left end 11a of the fourth refrigerant pipe 10D), and the right end 11a corresponds to the downstream end. One end 11a on the right side is connected to the outlet pipe 8. The connections between the refrigerant pipes 10 are made through a main connector 30 and upper and lower connecting pipes 38, which are part of a common structure.

[0047] In evaporator 4, specially designed slit fins 20 are used (see reference). Figure 5 ) and straight fin 28 with a structure simpler than slit fin 20 (see reference) Figure 8 The slit fin 20 is a new part in the evaporator 4 (or the heat exchanger assembly) of the refrigerator 1.

[0048] In evaporator 4, for example, the one configured on the downstream side Figure 2 The fourth refrigerant pipe 10D and the fifth refrigerant pipe 10E shown are equipped with slit fins 20. Alternatively, the other refrigerant pipes 10 may be equipped with straight fins 28. However, slit fins 20 may be used only if the gap between the fins in each refrigerant pipe 10 in the third direction D3 (the gap between the flat plates 21) exceeds 5 mm. The slit fins 20 have protruding pieces 26 and 27; therefore, the permissibility of the slit fin installation can be determined based on the gap between the fins in the third direction D3. Furthermore, Figure 2 The illustrations of protruding pieces 26 and 27 are omitted. Furthermore, in this embodiment, a reference value of "5 mm" is shown as the fin gap, but a value less than 5 mm can also be set as the reference value for setting the gap of the slit fin 20.

[0049] like Figure 2 and Figure 3As shown, a plurality of slit fins 20 are installed on a refrigerant pipe 10. The plurality of slit fins 20 are installed in such a way that two pipe sections 11 pass through each other. The plurality of slit fins 20 are arranged at predetermined gaps in a third direction D3. The third direction D3 is the extension direction of the pipe section 11 orthogonal to the first direction D1. The second direction D2 is a direction orthogonal to both the first direction D1 and the third direction D3.

[0050] like Figure 5 and Figure 6 As shown in (a), each slit fin 20 has a flat plate 21 with two elongated holes 22 through which two tube sections 11 pass. The thickness of the flat plate 21 is, for example, less than 1 mm. The thickness of the flat plate 21 is preferably less than 0.5 mm, more preferably less than 0.3 mm. In the rectangular flat plate 21, its thickness direction is oriented towards the third direction D3. That is, all flat plate sections 21 are arranged in an orientation orthogonal to the third direction D3. Each elongated hole 22 has a shape and size suitable for the shape of the tube section 11. The position of the two elongated holes 22 is suitable for the positional relationship of the two tube sections 11 in the refrigerant tube 10. A flange 25 protruding relative to the flat plate 21 is provided at the periphery of each elongated hole 22. The height of the flange 25, measured from the flat plate 21, is, for example, about 1.5 mm. Each tube section 11 is inserted into each elongated hole 22 and is joined to the flat plate 21 of the slit fin 20 by brazing.

[0051] Each slit fin 20 has a plurality of protruding pieces 26, which are formed by dividing a rectangular portion of a part of the flat plate 21, excluding the connecting end edge 26b, relative to the flat plate 21 and obliquely lifting the rectangular portion from the flat plate 21. Each of the plurality of protruding pieces 26 is formed by obliquely lifting the rectangular portion on one side of the flat plate 21 (the side opposite to the first surface 21a). Furthermore, each slit fin 20 has a plurality of protruding pieces (another type of protruding piece) 27, which are formed by dividing a rectangular portion of a part of the flat plate 21, excluding the connecting end edge 27b, relative to the flat plate 21 and obliquely lifting the rectangular portion from the flat plate 21. Each of the plurality of protruding pieces 27 is formed by obliquely lifting the rectangular portion on the other side of the flat plate 21 (the side opposite to the first surface 21a, the second surface 21b). Figure 6 When viewed in the direction shown in (a) (when viewed from a direction perpendicular to the plate portion 21), the rectangular portions constituting these protrusions 26, 27 extend longer in the second direction D2. The protrusions 26 and 27, for example, have the same shape and size. After removing each of the protrusions 26, 27, a rectangular slit 29 is formed on the plate portion 21.

[0052] Two protruding pieces 26 and two protruding pieces 27 are alternately arranged between a pair of short edge ends 23, 23 of the flat plate portion 21. A total of four protruding pieces 26, 27 are grouped together, and three groups (alternatingly arranged) of protruding pieces 26, 27 are provided on the flat plate portion 21. The first group of protruding pieces 26, 27 is located between one short edge end 23 and the elongated hole portion 22; the second group of protruding pieces 26, 27 is located between two elongated holes 22; and the third group of protruding pieces 26, 27 is located between another short edge end 23 and the elongated hole portion 22. The positions of the connecting edge 26b of the protruding piece 26 and the connecting edge 27b of the protruding piece 27 are both set to be opposite sides of each other. The number and arrangement of these protrusions are not limited to the above example and can be varied appropriately.

[0053] like Figure 6 As shown in (a), the ratio (z1 / z2) of the size (z1) of each of the protruding pieces 26 and 27 in the first direction D1 to the spacing (z2) of the protruding pieces 26 and 27 in the first direction D1 is, for example, a value in the range of 0.3 or more and 0.5 or less. Furthermore, as... Figure 6 As shown in (b), the protrusion height h of each of the protruding pieces 26 and 27 protruding from the flat plate portion 21 can be arbitrarily set within the range of 5 mm or less. The protrusion height h can also be uniformly shared (all the same) among the multiple slit fins 20 provided on a refrigerant pipe 10, but the protrusion height h can also be changed locally.

[0054] Compared to the case where slit fins 20 are provided, when straight fins 28 are provided on the evaporator 4, more straight fins 28 are installed on a single refrigerant pipe 10. The straight fins 28 can also be configured such that the gap between the straight fins 28 in the third direction D3 is less than 5 mm (however, in this case, measures are implemented to counteract frost buildup and blockage of the airflow). Figure 8 As shown, the only difference between the straight fin 28 and the slit fin 20 is that the straight fin 28 does not have protruding pieces 26 and 27 formed on the flat plate portion 21. The shape, size, and thickness of the flat plate portion 21 of the straight fin 28 are the same as those of the flat plate portion 21 of the slit fin 20. Furthermore, the two elongated holes 22 (and flange portions 25) formed on the flat plate portion 21 are also the same as those on the slit fin 20. The straight fin 28 can be considered a part obtained during the manufacturing process of the slit fin 20 (before the formation of the protruding pieces 26 and 27).

[0055] In the evaporator 4 with the above structure, the spacing of the plurality of straight fins 28 provided at the first refrigerant pipe 10A, the second refrigerant pipe 10B, and the third refrigerant pipe 10C is, for example, equal. Alternatively, the spacing of the straight fins 28 may be larger the lower the refrigerant pipe 10. The spacing of the plurality of slit fins 20 provided at the fourth refrigerant pipe 10D is greater than the spacing of the straight fins 28 provided at the third refrigerant pipe 10C. The spacing of the plurality of slit fins 20 provided at the fifth refrigerant pipe 10E is also further greater than the spacing of the slit fins 20 provided at the fourth refrigerant pipe 10D.

[0056] On one hand, refrigerant passes through the refrigerant flow path 14 of the multiple refrigerant pipes 10 of the evaporator 4. On the other hand, outside the multiple refrigerant pipes 10, air passes from bottom to top in the first direction D1 between the slit fins 20 and the straight fins 28 (see reference). Figure 1 The airflow direction is shown as R. The refrigerant absorbs heat from the air and evaporates.

[0057] From the viewpoint of heat exchange efficiency, the flat tube section 11 with multiple refrigerant flow paths 14 arranged according to the evaporator 4 of this embodiment is more advantageous than conventional finned and tubular heat exchangers. Furthermore, the structure of the evaporator 4, which includes refrigerant pipes 10 composed of such flat tube sections 11 and flat slit fins 20 or straight fins 28, is less prone to frost buildup blocking the airflow. Therefore, according to the evaporator 4, the problem of frost buildup blocking the airflow can be reduced, and heat exchange efficiency can be improved. According to the refrigerator 1 of this embodiment, heat exchange efficiency can be improved and energy consumption reduced. Energy consumption can be further reduced by extending the defrost interval. Moreover, since frost buildup blocking the airflow is less likely to occur, heat exchange efficiency can be ensured even with a smaller evaporator than conventional evaporators. Therefore, miniaturization of the evaporator 4 is possible. As a result, the storage capacity of the refrigerator 1 can be increased.

[0058] The refrigerant pipe 10 has an overall U-shaped structure in which two pipe sections 11 are opposed to each other in the second direction D2 and a bend 13 is provided between the two pipe sections 11. The bend 13 is equivalent to a foldback section of the refrigerant pipe 10. The inlet end and outlet end of the refrigerant pipe 10 can be arranged on the same side (one side end face). This arrangement is advantageous in terms of heat exchange efficiency and miniaturization of the evaporator 4.

[0059] Each of the slit fins 20 and straight fins 28 has a flat plate portion 21 with at least one elongated hole 22 through which the refrigerant pipe 11 passes, and a flange portion 25 protruding relative to the flat plate portion 21 is provided at the periphery of the elongated hole portion 22. This ensures good contact between the refrigerant pipe 10 portion 11 and the slit fins 20 or the straight fins 28, reducing contact thermal resistance.

[0060] By using slit fins 20, the heat exchange efficiency of the lower layer is improved. Furthermore, the area of ​​direct air contact is increased, thus promoting frost formation in the lower layer. This, in turn, suppresses frost formation at narrower sections between the fins in the upper layer.

[0061] The slit fin 20 has: a flat plate portion 21 having at least one elongated hole 22 through which the tube portion 11 passes; and a protruding piece 26 formed by dividing a portion of the flat plate portion 21, excluding the connecting end edge, relative to the flat plate portion 21 and obliquely lifting that portion from the flat plate portion 21. Thus, the heat exchange efficiency with air is improved by the protruding piece 26. The protruding piece 26 is cantilevered (connected to the flat plate portion 21 only through the connecting end edge 26b, with the rest open), therefore, condensation is less likely to accumulate, and the protruding piece 26 also undergoes elastic deformation when frost forms, thus preventing damage to the slit.

[0062] The slit fin 20 has a protruding piece 26 formed by partially raising one side of the flat plate portion 21 at an angle, and another protruding piece 27 formed by dividing a portion of another part of the flat plate portion 21, excluding the connecting end edge, relative to the flat plate portion 21 and raising that other part at an angle to the other side of the flat plate portion 21. The protruding piece 26 and the other protruding piece 27 protrude alternately on one side and the other side of the flat plate portion 21, thereby improving the turbulence effect of the airflow.

[0063] In the slit fin 20, the plate portion 21 is partially and partially rectangular, extending longer along a second direction D2 orthogonal to both the first direction D1 and the third direction D3. The ratio (z1 / z2) of the size (z1) of each of the protruding pieces 26 and 27 in the first direction D1 to the spacing (z2) between them in the first direction D1 is a value in the range of 0.3 or more and 0.5 or less. This prevents the protruding pieces 26 and 27 from being arranged too densely. Overly dense protruding pieces will, for example, cause a decrease in airflow due to increased pressure loss. The decrease in airflow leads to a decrease in heat flux. Furthermore, during de-icing, ice easily gets caught on the protruding pieces, causing ice residue. With the above-described appropriate arrangement (density), good heat exchange can be achieved.

[0064] In the slit fin 20, the protrusion height h of the protruding pieces 26 and 27 relative to the flat plate 21 can be arbitrarily set within a range of 5 mm or less. Therefore, the protrusion height h can be appropriately selected from different heights such as 1 mm, 2 mm, and 3 mm, making performance adjustments easy. For example, in areas prone to frost buildup and airflow blockage, the protrusion height can be reduced, or it can be increased to accommodate hooking. Since protruding pieces of various heights can be provided within a single fin, one protruding piece can be configured to not overlap when viewed from the airflow direction, potentially improving heat transfer efficiency. Furthermore, even when airflow speed or pressure changes due to airflow path or fan, the same evaporator can be used to adapt to various conditions.

[0065] Multiple refrigerant pipes 10 are stacked in a first direction D1. At the inlet or outlet end of each refrigerant pipe 10 section 11, a main connector 30 is installed, consisting of a flat, rectangular first connecting portion 31 and a cylindrical second connecting portion 32 connected to the first connecting portion 31. The multiple main connectors 30 connect the multiple refrigerant pipes 10 in series. The main connectors 30 allow for easy connection between upper and lower refrigerant pipes 10. While existing connectors cause significant pressure drops, the main connector 30 disclosed herein effectively reduces flow resistance within the pipe sections 11. This reduces pressure drop, decreases power consumption in the compressor 6, and contributes to improved energy efficiency of the refrigerator 1.

[0066] The ratio of the length E of the tube section 11 in the first direction D1 to the width F of the tube section 11, i.e., the aspect ratio, is a value within the range of 4 or more and 10 or less. This appropriately achieves the aforementioned effects (improved heat exchange ratio and prevention of frost adhesion, etc.). The narrower the width F, the less airflow resistance on the air side and the more effective heat conduction area. That is, air is less likely to contact the lower surface portion of the tube section 11 relative to the downstream outer surface 11c and inner surface 11d, nor the upper surface portion of the tube section 11, thus improving phenomena such as reduced heat exchange efficiency. However, if the width F is reduced, the refrigerant flow resistance also increases. Considering the balance between these factors, the aforementioned aspect ratio is preferred.

[0067] The number of refrigerant flow paths 14 provided within the pipe section 11 is between 3 and 10. This suppresses refrigerant flow resistance and ensures good heat exchange. More specifically, the refrigerant flow rate is determined based on the refrigeration cycle of the refrigerator 1. The aforementioned number is an appropriate amount that appropriately promotes refrigerant evaporation.

[0068] The embodiments of this disclosure have been described above, but the present invention is not limited to the above embodiments. For example, the design specifications related to the tube section 11 (the aspect ratio, the number of refrigerant flow paths 14, and the design specifications related to the protruding pieces 26 and 27) can also be appropriately changed. Alternatively, in the slit fin 20, the protruding piece 27 can be omitted, and only the protruding piece 26 can be formed.

[0069] Alternatively, the slit fins 20 can be omitted, and only a number of straight fins 28 can be installed in all refrigerant pipes 10.

[0070] The structure of each refrigerant pipe 10 is not limited to a U-shape. A main connector 30 may also be provided at both ends of the pipe section 11. Alternatively, a refrigerant pipe 10 may have only one pipe section 11.

Claims

1. An evaporator, characterized by have: At least one refrigerant pipe is formed by having a plurality of flat pipe sections that arrange a plurality of refrigerant flow paths in a first direction, and by connecting the pipe sections in the refrigerant flow direction. Multiple flat fins are mounted on the tube in a manner that allows the tube to pass through, and are arranged at intervals in the extending direction of the tube orthogonal to the first direction; and An inlet pipe connected to the upstream end of the refrigerant pipe and an outlet pipe connected to the downstream end of the refrigerant pipe.

2. The evaporator according to claim 1, characterized in that, The refrigerant pipe has an overall U-shaped structure in which two pipe sections are opposed to each other in a second direction orthogonal to both the first direction and the extension direction, and a bend is provided between the two pipe sections.

3. The evaporator according to claim 1 or 2, characterized in that, Each fin has a flat plate portion having at least one elongated hole through which the tube portion passes, and a flange portion protruding from the flat plate portion is provided at the periphery of the elongated hole portion.

4. The evaporator according to claim 1 or 2, characterized in that, Each fin has: a flat plate portion having at least one elongated hole through which the tube portion passes; and a protruding piece formed by cutting a portion of the flat plate portion, excluding the connecting end edge, relative to the flat plate portion and lifting the portion obliquely relative to the flat plate portion.

5. The evaporator according to claim 4, characterized in that, Each of the fins has: The protruding piece is formed by obliquely lifting the portion on one side of the flat plate; and Another type of protruding piece is formed by cutting off a portion of another part of the flat plate relative to the flat plate, excluding the connecting edge, and raising that other part obliquely on the other side of the flat plate.

6. The evaporator according to claim 5, characterized in that, The portion and the other portion of the flat plate are each a rectangle that extends relatively long in a second direction orthogonal to both the first direction and the extending direction. The ratio z1 / z2 of the size z1 of each of the protruding pieces in the first direction to the interval z2 between the protruding pieces and the other protruding piece in the first direction is a value in the range of 0.3 or more and 0.5 or less.

7. The evaporator according to claim 4, characterized in that, The protrusion height of the protruding piece relative to the flat plate can be arbitrarily set within a range of less than 5mm.

8. The evaporator according to claim 1 or 2, characterized in that, The facility is provided with a plurality of refrigerant pipes, which are stacked in the first direction. A main connector, consisting of a flat, rectangular first connecting part and a cylindrical second connecting part connected to the first connecting part, is installed at the inlet or outlet end of each of the refrigerant pipes. The refrigerant pipes are connected in series through multiple main connectors.

9. The evaporator according to claim 1 or 2, characterized in that, The ratio of the length of the tube in the first direction to the width of the tube, i.e., the aspect ratio, is a value in the range of 4 or more and 10 or less.

10. The evaporator according to claim 1 or 2, characterized in that, The number of refrigerant flow paths provided within the pipe section is in the range of 3 or more and 10 or less.

11. A refrigerator, characterized in that, It has an evaporator as described in claim 1 or 2.

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