Plate-fin stacked heat exchanger and refrigeration system using same
Patent Information
- Application Number
- JP2021101280
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2021-06-18
- Publication Date
- 2025-04-25
- Estimated Expiration
- 2041-06-18
AI Technical Summary
Existing plate-fin laminated heat exchangers suffer from insufficient heat exchange performance in the vicinity of the header flow path due to refrigerant temperature gradients, leading to cold air passing through without adequate heat exchange.
The heat transfer channel is configured to make multiple turns and extend to overlap with the header flow path, enhancing heat exchange at the turn portion, while maintaining a stable flow path resistance.
This configuration improves heat exchange performance near the header flow path, ensuring effective heat transfer and maintaining high efficiency without increasing flow resistance.
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Abstract
Description
[Technical Field]
[0001] The present disclosure relates to a plate-fin stacked heat exchanger and a refrigeration system using the same. [Background technology]
[0002] Patent Document 1 discloses a plate-fin stack-type heat exchanger. This plate-fin stack-type heat exchanger is configured by stacking multiple plate fins, each having a pair of header flow paths and a heat transfer flow path, and is configured so that a first fluid that flows from one header flow path into a heat transfer flow path flows to the other header flow path, which serves as an outlet, and heat is exchanged between the first fluid flowing in the heat transfer flow path and a second fluid, such as air, that flows through the gaps between the plate fins. [Prior art documents] [Patent documents]
[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-180856 Summary of the Invention [Problem to be solved by the invention]
[0004] The present disclosure provides a plate fin stacked heat exchanger in which the heat exchange effect in the portion of the plate fins immediately adjacent to the header flow path is improved, and a refrigeration system using the same. [Means for solving the problem]
[0005] The plate fin stack type heat exchanger of the present disclosure is configured by stacking a plurality of plate fins, each having a pair of header flow paths and a heat transfer flow path, wherein the heat transfer flow paths make several turns between the header flow paths to connect the header flow paths, and the turning portion of the heat transfer flow path that turns on one of the header flow paths extends to a position where it overlaps with at least the heat transfer flow path outlet portion of the header flow path in the flow direction of the second fluid flowing between the plate fins. [Effects of the Invention]
[0006] With the above-described configuration, the plate-fin stacked heat exchanger of the present disclosure has the second fluid passing through the portion immediately adjacent to the header flow path passing through the turning portion of the heat transfer flow path that overlaps with the heat transfer flow path outlet portion of the header flow path, thereby improving the heat exchange performance in the portion immediately adjacent to the header flow path, resulting in a high-performance plate-fin stacked heat exchanger and a refrigeration system using it. [Brief explanation of the drawings]
[0007] [Figure 1] FIG. 1 is a perspective view showing the appearance of a plate fin stack type heat exchanger according to a first embodiment. [Figure 2] FIG. 1 is an exploded perspective view of the plate fin stacked heat exchanger. [Figure 3] FIG. 10 is a perspective view showing a main part of the plate fin stack of the plate fin stack type heat exchanger. [Figure 4] FIG. 10 is a perspective view showing the plate fin stacking state of the plate fin stack type heat exchanger of the same embodiment; [Figure 5] FIG. 10 is a perspective view showing the plate fins of the plate fin stacked heat exchanger of the same embodiment; [Figure 6] Refrigeration cycle diagram of an air conditioner showing an example of a refrigeration system using the plate fin stacked type heat exchanger. [Figure 7] FIG. 3 is a cross-sectional view showing an indoor unit of the air conditioner. [Figure 8] FIG. 1 is a perspective view showing plate fins of a plate fin stack type heat exchanger prior to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION
[0008] (Findings that formed the basis of this disclosure) At the time the inventors arrived at the idea of the present disclosure, a plate fin stack type heat exchanger was configured by stacking a plurality of plate fins, each having a heat transfer flow path through which a first fluid, such as a refrigerant, flows between a pair of header flow paths, as shown in Patent Document 1. However, the heat transfer flow path was configured to branch into multiple paths via multiple branch flow paths, allowing the first fluid, such as a refrigerant, to flow, resulting in a complex flow path configuration.
[0009] Therefore, in order to simplify the configuration of the heat transfer flow path, the inventors have designed a configuration in which one heat transfer flow path 102 extending from one header flow path 101 is turned at the other end side, and this turning is repeated several times to connect to a header flow path 103 at the other end side, as shown in FIG. 8, thereby simplifying the configuration of the heat transfer flow path 102.
[0010] However, with the above configuration, in the portion immediately adjacent to the header channel 102, a portion of the second fluid passes only through the header channel outlet portion 102a of the heat transfer channel 102 as indicated by arrow Z.
[0011] Here, a temperature gradient occurs in the refrigerant flowing through the heat transfer flow path 8 from the header flow path 101 on the inlet side to the header flow path 103 on the outlet side due to heat exchange with the air, and when the heat exchanger is used as a condenser that serves as a heating heat source for an air conditioner, for example, the refrigerant becomes supercooled and has a low temperature in the portion immediately adjacent to the header flow path 103 on the outlet side. As a result, it was discovered that a sufficient heat exchange effect cannot be obtained in the portion immediately adjacent to the header flow path 103, and the indoor air passes through almost as it is in the form of cold air without heat exchange.
[0012] The present inventors have discovered this problem and have come to form the subject of the present disclosure in order to solve the problem.
[0013] Therefore, the present disclosure provides a plate-fin stacked heat exchanger that improves heat exchange performance by increasing the heat exchange action in the vicinity of the header flow path, and a refrigeration system using the same.
[0014] Hereinafter, embodiments will be described in detail with reference to the drawings. However, unnecessary detailed description may be omitted. For example, detailed description of well-known matters or redundant description of substantially the same configuration may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art.
[0015] The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.
[0016] (Embodiment 1) Hereinafter, the first embodiment will be described with reference to FIGS.
[0017] [1-1.Configuration] 1 and 2, heat exchanger 1 of this embodiment is configured by integrally joining end plates 3a, 3b, which have approximately the same shape in a plan view, to both sides of plate fin stack 2, which is made up of stacked rectangular plate fins 2a. At the ends of the plate fin stack 2, tube A4 serves as an inlet when used as a condenser and as an outlet when used as an evaporator, and tube B5 serves the opposite purpose.
[0018] The end plates 3a, 3b on both sides of the plate fin stack 2 are brazed together while sandwiching the plate fin stack 2, and both longitudinal ends are connected and fixed by fastening means 7, maintaining the rigidity of the heat exchanger.
[0019] The plate fins 2a are configured by joining a pair of plates 6a, 6b shown in Fig. 4 by brazing or the like to have heat transfer paths 8 through which a first fluid such as a refrigerant (hereinafter referred to as refrigerant) flows, and as shown in Fig. 3, a plurality of plate fins 2a are stacked to form stack gaps between the adjacent plate fins 2a through which a second fluid such as air (hereinafter referred to as air) flows. Heat is exchanged between the refrigerant flowing through the heat transfer paths 8 provided in the plate fins 2a and the air flowing through the stack gaps between the adjacent plate fins 2a.
[0020] As shown in FIG. 4, the pair of plates 6a, 6b constituting the plate fin 2a have openings A9a and B10a that form header flow paths A9 and B10 that connect to tubes A4 and B5, respectively, and ring-shaped grooves 9b and 10b provided on the opening edges, as well as a flow path-forming groove 8a that connects the header flow paths A9 and B10.
[0021] The pair of plates 6a, 6b are brazed facing each other to form the header flow path A9, the header flow path B10, and the heat transfer flow path 8 connecting the header flow path A9 and the header flow path B10.
[0022] 5, the heat transfer flow path 8 is configured such that the end of the heat transfer flow path 8 drawn out from one header flow path A9, which is the inlet side, is folded back several times and connected to the other end of the header flow path B10, which is the outlet side. In this example, the header flow paths A9 and B10 are connected together by making two turns.
[0023] Furthermore, in the heat transfer flow path 8, the turn portion 11a of the heat transfer flow path 8 that turns at least on the side of the one header flow path B10 is extended and turned to a position where it overlaps with the header flow path B10 in the flow direction of the second fluid (hereinafter referred to as air) flowing between the plate fins 2a indicated by the arrow X.
[0024] In this example, it extends to a position opposite the outermost end 10c of the header flow path B10, but it may also extend to the heat transfer flow path outlet portion 8b which is the terminal end of the flow path region L.
[0025] Furthermore, the heat transfer flow path 8 is configured to have one flow path turn, but if necessary, a plurality of flow paths may be arranged in parallel and turned between the header flow paths A9 and B10.
[0026] The plate fins 2a are provided with slits 12 between the turned heat transfer flow paths 8 to prevent heat transfer between adjacent flow paths.
[0027] Furthermore, the plate fins 2a configured as described above have a plurality of protrusions 13 (see FIG. 4) appropriately provided along the longitudinal direction of the heat transfer flow path 8 of the plate fins 2a to form stacking gaps through which air can flow.
[0028] [1-2. Operation] Next, the effects of the plate-fin stacked heat exchanger constructed as described above will be explained using as an example a case where it is used as a heat exchanger for an air conditioner.
[0029] When the heat exchanger of this embodiment is used under condensing conditions, for example, gas-phase liquid refrigerant flows from tube A4 into header flow path A9 on the inlet side of the plate fin stack 2. The gas-phase refrigerant that has flowed into header flow path A9 flows through the heat transfer flow paths 8 of each plate fin 2a, turns at each turn portion 11, and flows out of tube B5 via header flow path B10 on the outlet side into the refrigeration system's refrigerant circuit.
[0030] Then, while flowing through the heat transfer flow path 8, the refrigerant exchanges heat with the air passing through the gaps between the plate fins of the plate fin stack 2, and the gas phase refrigerant gradually becomes liquid phase and flows out of the header flow path B10.
[0031] Here, the refrigerant in the portion immediately adjacent to the header flow path B10 on the outlet side is in a supercooled state, and is in a liquid phase with a low temperature, so the temperature difference with the air passing through the gaps between the plate fins is small. Therefore, almost no heat exchange occurs in this portion.
[0032] However, in this heat exchanger, there is a turn portion 11a formed by turning back the heat transfer flow path 8 in the air flow direction of the header flow path B10, i.e., downstream of the header flow path B10. The refrigerant in the turn portion 11a immediately downstream of the header flow path B10 is in the gas phase or a gas-liquid two-phase state and is at a high temperature. Therefore, heat exchange with the air flowing in the vicinity of the header flow path B10 occurs in the turn portion 11a, enhancing the heat exchange effect in the vicinity of the header flow path B10. In other words, it is possible to prevent the air flowing in the vicinity of the header flow path B10 from passing through as cold air without undergoing heat exchange.
[0033] In particular, in this embodiment, the turn portion 11a extends beyond the heat transfer flow path outlet portion 8b to a position opposite the outermost peripheral end 10c of the header flow path B10, and therefore overlaps with the header flow path B10. Therefore, even if air flows into the header flow path B10, heat exchange can be performed in the turn portion 11a. As a result, even if the air flows into the header flow path B10, heat exchange with the air can be performed, and the air can be reliably prevented from passing through the portion immediately adjacent to the header flow path B10 as cool air.
[0034] In the above configuration, the header flow path B10, which overlaps the turn portion 11a, has a smaller flow path diameter by the amount of overlapping the turn portion 11a. However, because the refrigerant is in a liquid phase on the header flow path B10 side, flow path resistance is low even with the small diameter. Therefore, there is almost no reduction in heat exchange performance due to increased flow path resistance caused by reducing the flow path diameter. Therefore, the configuration of this embodiment, in which the turn portion 11a is provided downstream of the header flow path B10, can effectively improve heat exchange performance.
[0035] This heat exchanger may also have a turn section 11a on the other header flow path A9 side that overlaps with the header flow path B10. However, because the refrigerant is in the gas phase on the other header flow path A9 side, reducing the flow path diameter A9 increases the flow resistance of the refrigerant. This increased flow resistance reduces the heat exchange effect, and this reduction in heat exchange effect is equal to or greater than the heat exchange enhancement effect achieved by providing an overlapping turn section on the header flow path A9. For this reason, the heat exchanger of this embodiment is configured so that no overlapping turn section is provided on the header flow path A9 side through which the gas-phase refrigerant flows.
[0036] As a result, when this heat exchanger is used under condensing conditions, the heat exchange performance on the header flow path A9 side can be maintained at a high level, and the improved heat exchange performance on the header flow path B10 side can be a positive factor, making the heat exchange performance of the heat exchanger as a whole well-balanced and high.
[0037] Furthermore, in the heat exchanger of this embodiment, the slits 12 are eliminated between adjacent flow paths of the turn portion 11a that overlaps with the header flow path B10, making the heat exchanger slitless. This allows the temperature in the area where the turn portion 11a is present to be kept relatively high and stable. This further enhances the heat exchange effect of the air flowing in the vicinity of the header flow path A9.
[0038] [1-3. Effects, etc.] As described above, the plate fin stack type heat exchanger of the present disclosure is a plate fin stack type heat exchanger configured by stacking a plurality of plate fins 2a, each of which has a pair of header flow paths A9, B10b and a heat transfer flow path 8, and the heat transfer flow path 8 is configured to turn several times between the header flow paths A9, 9b to connect the header flow paths, and the turning portion 11a of the heat transfer flow path 8 that turns on the side of one header flow path B10 extends to a position where it overlaps with at least the heat transfer flow path outlet portion 10a of the header flow path B10 in the flow direction of the second fluid flowing between the plate fins 2a.
[0039] As a result, the second fluid passing through the portion immediately adjacent to the header flow path B10 passes through the turn portion 11a of the heat transfer flow path 8, which overlaps with the heat transfer flow path outlet portion 8b of the header flow path B10, and exchanges heat with the first fluid, improving the heat exchange performance in the portion immediately adjacent to the header flow path B10 and making it possible to create a high-performance plate-fin stacked type root exchanger.
[0040] Furthermore, in the plate fin stacked heat exchanger of the present disclosure, the turn portion 11a extends beyond the heat transfer flow path outlet portion 8b to a position facing the outermost peripheral end 10c of the header flow path B10, and overlaps with the header flow path B10.
[0041] This allows heat exchange with the air flowing through the header flow path B10, and the heat exchange performance in the immediate vicinity of the header flow path B10 can be improved more reliably.
[0042] Furthermore, the plate fin stacked heat exchanger of the present disclosure is configured such that the turn portion 11a is provided only on the header flow path 11b side, and does not extend in the flow direction of the second fluid on the other header flow path A9 side.
[0043] As a result, the header flow path A9 on the side where the turn portion does not extend in the flow direction of the second fluid can be ensured to have a sufficient size without its flow path diameter being restricted by the turn portion. Therefore, it is possible to prevent an increase in flow path resistance and a decrease in heat exchange action due to a restriction in the flow path diameter of the header flow path A9, and to maintain a high heat exchange action. Therefore, when the first fluid is a refrigerant and the heat exchanger is used as a condenser, it is possible to prevent cold air from passing through in the vicinity of the other header flow path B10, thereby improving heat exchange performance, and at the same time, it is possible to ensure the heat exchange action on the other header flow path A9 side without reducing it, thereby increasing the heat exchange action of the entire heat exchanger.
[0044] Furthermore, the plate-fin stacked heat exchanger of the present disclosure has slits 12 between adjacent heat transfer flow paths 8 connecting header flow paths A9 and B10, and the turn portion 11a extends to a position where it overlaps with the heat transfer flow path outlet portion 8b of one of the header flow paths B10, and the flow paths are slitless.
[0045] This allows the temperature in the vicinity of the turn portion 11a to be kept high and stable, and the heat exchange action with the second fluid passing through the portion immediately adjacent to the header flow path B10 can be more effectively enhanced.
[0046] (Embodiment 2) The second embodiment will be described below with reference to FIGS.
[0047] [2-1.Configuration] FIG. 6 is a diagram showing a refrigeration cycle of an air conditioner configured using the plate fin stacked type heat exchanger according to the first embodiment, and FIG. 7 is a schematic cross-sectional view showing an indoor unit of the same air conditioner.
[0048] 6 and 7, this air conditioner is composed of an outdoor unit 51 and an indoor unit 52 connected to the outdoor unit 51. The outdoor unit 51 is provided with a compressor 53 that compresses a refrigerant, a four-way valve 54 that switches the refrigerant circuit during cooling or heating operation, an outdoor heat exchanger 55 that exchanges heat between the refrigerant and outside air, a pressure reducer 56 that reduces the pressure of the refrigerant, and an outdoor fan 59. The indoor unit 52 is provided with an indoor heat exchanger 57 that exchanges heat between the refrigerant and indoor air, and an indoor fan 58. The indoor heat exchanger 57 is the plate-fin stacked type heat exchanger exemplified in the first embodiment, and the compressor 53, four-way valve 54, indoor heat exchanger 57, pressure reducer 56, and outdoor heat exchanger 55 are connected by a refrigerant circuit to form a heat pump refrigeration cycle.
[0049] [2-2. Operation] During cooling operation, the air conditioner configured as described above switches the four-way valve 54 so that the discharge side of the compressor 53 communicates with the outdoor heat exchanger 55. As a result, the refrigerant compressed by the compressor 53 becomes a high-temperature, high-pressure gas-phase refrigerant and is sent through the four-way valve 54 to the outdoor heat exchanger 55. The refrigerant then exchanges heat with the outside air, releasing heat, becoming a high-pressure liquid-phase refrigerant and being sent to the pressure reducer 56. The pressure is reduced in the pressure reducer 56 to become a low-temperature, low-pressure two-phase refrigerant and sent to the indoor unit 52. In the indoor unit 52, the refrigerant enters the indoor heat exchanger 57, where it exchanges heat with the indoor air, absorbing heat and evaporating to become a low-temperature gas refrigerant. At this time, the indoor air is cooled, cooling the room. The refrigerant then returns to the outdoor unit 51 and is returned to the compressor 53 via the four-way valve 54.
[0050] On the other hand, during heating operation, the four-way valve 54 is switched so that the discharge side of the compressor 53 communicates with the indoor unit 52. As a result, the refrigerant compressed by the compressor 53 becomes a high-temperature, high-pressure gas-phase refrigerant, passes through the four-way valve 54, and is sent to the indoor unit 52. The high-temperature, high-pressure gas-phase refrigerant enters the indoor heat exchanger 57, exchanges heat with the indoor air, releases heat, is cooled, and becomes a low-temperature, high-pressure liquid-phase refrigerant, which flows out of the indoor heat exchanger 57.
[0051] At this time, the indoor air is heated to heat the room. Even if the refrigerant is in a low-temperature state in the vicinity of the header flow path B10 on the refrigerant outflow side of the indoor heat exchanger 57, it is heated by heat exchange with the high-temperature, high-pressure refrigerant in the turning portion 11a downstream of the header flow path 10 on the refrigerant outflow side, as explained in the first embodiment, and is prevented from passing through as cold air, thereby providing high-quality heating with less feeling of cold air.
[0052] The refrigerant is then sent to the pressure reducer 56, where it is reduced in pressure to become a low-temperature, low-pressure two-phase refrigerant. It is then sent to the outdoor heat exchanger 55, where it exchanges heat with the outside air and evaporates, and is returned to the compressor 53 via the four-way valve 54.
[0053] [2-3. Effects, etc.] As described above, the refrigeration system of the present disclosure includes a heat exchanger and a blower fan, and the indoor heat exchanger is the plate-fin stacked type heat exchanger described in the first embodiment.
[0054] This allows for a high heat exchange effect even in the vicinity of the header flow path, resulting in a refrigeration system with high thermal efficiency and high performance.
[0055] [Other embodiments] The plate-fin stacked heat exchanger and refrigeration system using the same according to the present invention have been described above using the above-mentioned embodiments. However, the present invention is not limited to these embodiments and various modifications, substitutions, additions, omissions, etc. may be made. For example, while the first fluid is a refrigerant and the second fluid is air, the present invention is not limited to these embodiments. Furthermore, while an air conditioner is used as the refrigeration system, the present invention may also be a heat pump water heater using water as the second fluid. In other words, the embodiments disclosed herein are illustrative in all respects and are not limiting. The scope of the present invention is defined by the claims, and all modifications within the meaning and scope of the claims are intended to be included. [Industrial Applicability]
[0056] As described above, the present invention provides a high-performance plate-fin stacked-type heat exchanger and a refrigeration system using the same, which improves heat exchange performance in the vicinity of the header flow path. Therefore, the present invention can be widely used in various refrigeration equipment, such as heat exchangers used in domestic and commercial air conditioners and heat pump water heaters, and has great industrial value. [Explanation of symbols]
[0057] 1 heat exchanger 2 Plate-fin laminate 2a Plate fin 3a, 3b End plates 4 Pipe A 5 Tube B 6a Plate 6b Plate 7 Fastening means (bolts and nuts) 8 Heat transfer channel 8a Flow path forming groove 8b Heat transfer channel lead-out part 9 Header flow path A 10 Header flow path B 10a Heat transfer channel outlet 11 Turn section 11a Turn 12 Slit 13 protrusions 51 Outdoor unit 52 Indoor unit 53 Compressor 54 Four-way valve 55 Outdoor heat exchanger 56 Pressure Reducer 57 Indoor heat exchanger 58 Indoor fan 59 Outdoor blower
Claims
1. A plate-fin stacked heat exchanger constructed by stacking a plurality of plate fins, each having a pair of header flow paths and a heat transfer flow path, wherein the heat transfer flow paths make several turns between the header flow paths to connect the header flow paths, and the turning portion of the heat transfer flow path that turns on one of the header flow paths extends to a position where it overlaps with at least the heat transfer flow path outlet portion of the header flow path in the flow direction of a second fluid flowing between the plate fins.
2. 2. The plate-fin stacked heat exchanger according to claim 1, wherein the turn portion extends beyond the heat transfer flow path outlet portion to a position opposite to the outermost peripheral end of the header flow path and overlaps with the header flow path.
3. 3. The plate-fin stack type heat exchanger according to claim 1, wherein the turn portion is provided only on one header flow path side and does not extend in the flow direction of the second fluid on the other header flow path side.
4. 4. The plate-fin stacked heat exchanger according to claim 1, wherein a slit is provided between adjacent flow paths of the heat transfer flow paths connecting the header flow paths, and a slit is not provided between the flow paths of the turn section that extends to a position where it overlaps with the heat transfer flow path outlet section of one of the header flow paths.
5. A refrigeration system comprising a heat exchanger and a blower fan, wherein the heat exchanger is the plate-fin stacked type heat exchanger according to any one of claims 1 to 4.