Heat exchanger and cooling circuit device

Abstract

A heat exchanger comprises a downstream heat exchanger unit arranged downstream in the direction of airflow, an upstream heat exchanger unit arranged further upstream in the direction of airflow than the downstream heat exchanger unit, and a common headpiece. The downstream heat exchanger unit comprises a downstream heat transfer tube array with heat transfer tubes arranged and spaced in a direction that crosses the direction of airflow, and a first headpiece connected to a lower portion of the downstream heat transfer tube array. The upstream heat exchanger unit comprises an upstream heat transfer tube array with heat transfer tubes arranged and spaced in a direction that crosses the direction of airflow, and a second headpiece connected to a lower portion of the upstream heat transfer tube array.The common headpiece is connected to an upper section of the downstream heat transfer pipe series and an upper section of the upstream heat transfer pipe series, and connects the downstream heat transfer pipe series and the upstream heat transfer pipe series.Then, if the downstream heat exchanger unit and the upstream heat exchanger unit each function as condensers, the downstream heat exchanger unit and the upstream heat exchanger unit each include a first section in which the refrigerant flowing into the first headpiece flows against the direction of airflow and into the second headpiece, a second section in which the refrigerant flowing through the first section and into the second headpiece flows parallel to the direction of airflow and into the first headpiece, and a third section in which the refrigerant flowing through the second section and into the first headpiece flows against the direction of airflow and into the second headpiece.

Description

TECHNICAL FIELD

[0001] The present invention relates to a heat exchanger and a refrigeration cycle device configured to exchange refrigerant heat. STATE OF THE ART

[0002] A known heat exchanger includes an upstream heat exchanger unit and a downstream heat exchanger unit connected in series in an air flow direction. To increase the performance of the heat exchanger, when the heat exchanger functions as a condenser, the refrigerant in a downstream region of the heat exchanger, where subcooled liquid flows, is directed in a direction opposite to the flow direction of the air flowing into the heat exchanger (see, for example, Patent Document 1).

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 7-98 162 A Summary of the inventionTechnical problem

[0004] Such a heat exchanger has the problem that the heat exchange performance is reduced because the refrigerant flows in a superheated gas region parallel to the air flow direction when the heat exchanger acts as a condenser.

[0005] The present invention has been made in view of the above circumstances and has an object to provide a heat exchanger and a refrigeration cycle device having improved heat exchange performance. Solution to the problem

[0006] A heat exchanger according to an embodiment of the present invention includes a downstream heat exchanger unit arranged downstream in an air flow direction, an upstream heat exchanger unit arranged further upstream in the air flow direction than the downstream heat exchanger unit, and a common header. The downstream heat exchanger unit includes a downstream heat transfer tube row with heat transfer tubes arranged and spaced apart in a direction crossing the air flow direction, and a first header connected to a lower end portion of the downstream heat transfer tube row. The upstream heat exchanger unit includes an upstream heat transfer tube row with heat transfer tubes arranged and spaced apart in a direction crossing the air flow direction, and a second header.which is connected to a lower end region of the upstream heat transfer tube row, wherein the common header is connected to an upper end region of the downstream heat transfer tube row and an upper end region of the upstream heat transfer tube row and connects the downstream heat transfer tube row and the upstream heat transfer tube row, and when the downstream heat exchanger unit and the upstream heat exchanger unit each function as a condenser, the downstream heat exchanger unit and the upstream heat exchanger unit have a first region in which the refrigerant flowing into the first distributor flows counter to the air flow direction and into the second distributor, a second region in which the refrigerant flowing through the first region and flowing into the second header flows parallel to the air flow direction and flows into the first header,and a third region in which the refrigerant flowing through the second region and flowing into the first header flows against the air flow direction and flows into the second header. Effect of the invention

[0007] The heat exchanger according to one embodiment of the present invention includes the first region, the second region, and the third region when functioning as a condenser. In the first region, the refrigerant flows counter to the air flow direction. In the second region, the refrigerant flows through the first region parallel to the air flow direction. In the third region, the refrigerant passing through the second region flows counter to the air flow direction.

[0008] When the heat exchanger functions as a condenser, the refrigerant flows against the air flow direction, in contrast to the prior art, in the first zone, which is a superheated gas zone, and in the third zone, which is a subcooled liquid zone. This improves the heat exchanger's heat exchange performance. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view of a refrigerant cycle of an air conditioning apparatus according to Embodiment 1; Fig. 2 is a perspective view of a heat exchanger according to Embodiment 1; Fig. 3 illustrates a state of refrigerant flow in the heat exchanger according to Embodiment 1; Fig. 4 illustrates a state of the refrigerant flowing in the heat exchanger according to Embodiment 1; Fig. 5 illustrates a state of refrigerant flow in a heat exchanger of an air conditioning apparatus according to Embodiment 2; Fig. 6 shows an arrangement of first headers and second headers of the heat exchanger in the air conditioning apparatus according to Embodiment 2; Fig. Fig. 7 illustrates a state in which two first heat exchangers and two second heat exchangers according to Embodiment 2 are arranged on four sides in an outdoor unit case such that the first and second heat exchangers surround a fan, and Fig. 8 shows a state in which a heat exchanger according to Embodiment 3 is arranged inside an outdoor unit case. DESCRIPTION OF THE EMBODIMENTS

[0009] A heat exchanger of an air conditioning device according to an embodiment will be described with reference to the drawings. Note that in the drawings, the same components are denoted by the same reference numerals, and redundant description will be given only when necessary. The present invention may include any possible combination of configurations that can be combined among the configurations described in the following embodiments. In the drawings, the size relationship of the components sometimes differs from the size relationship of the actual components. The shapes of the components illustrated throughout the description are merely examples, and the components are not limited to the shapes described in the description.In particular, the combination of the components is not limited to the combination in each of the embodiments, and a component described in one embodiment may be applied to another embodiment. Embodiment 1

[0010] Fig. 1 is a schematic view of a refrigerant cycle 110 of an air conditioning apparatus 300 according to Embodiment 1.

[0011] The refrigerant circuit 110 includes a compressor 6, a condenser 100a, an expansion valve 8 and an evaporator 100b.

[0012] In the air conditioning unit 300, an outdoor heat exchanger functions as a condenser 100a and an indoor heat exchanger functions as an evaporator 100b during a cooling operation. The outdoor heat exchanger functions as an evaporator 100b and the indoor heat exchanger functions as a condenser 100a during a heating operation.

[0013] Compressor 6 compresses the refrigerant drawn in and discharges it. Although compressor 6 is not particularly limited to the following, the capacity of compressor 6 can be changed by appropriately changing the operating frequency, for example, using a converter circuit. Note that the capacity of compressor 6 represents the amount of refrigerant to be delivered per unit.

[0014] Condenser 100a exchanges heat between the refrigerant discharged from compressor 6 and air. Condenser 100a condenses the refrigerant to be condensed.

[0015] The expansion valve 8 reduces the pressure of the refrigerant to expand the refrigerant. For example, if the expansion valve 8 is an electronic expansion valve, the opening degree of the expansion valve 8 is controlled according to an instruction from, for example, a controller (not shown).

[0016] The evaporator 100b exchanges heat between the air and the refrigerant. The evaporator 100b evaporates the refrigerant to be vaporized.

[0017] The single-phase gas refrigerant discharged from the compressor 6 is condensed into a single-phase liquid in the condenser 100a. The refrigerant condensed into a single-phase liquid in the condenser 100a flows through the expansion valve 8 and is converted into a two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant, having passed through the expansion valve 8, passes through the evaporator 100b and evaporates back into a single-phase gas. The single-phase gas refrigerant, having passed through the evaporator 100b, flows into the compressor 6.

[0018] Fig. 2 is a perspective view of a heat exchanger 100 according to Embodiment 1. The heat exchanger 100 shown in Fig. The heat exchanger 100 shown in Figure 2 is used in the condenser 100a. In Fig. 2, the flow direction of the air flowing into the heat exchanger 100, as indicated by the hollow arrow, is a direction from left to right in Fig. 2. In addition, the dashed arrows indicate the flow direction of the refrigerant when the heat exchanger 100 functions as a condenser 100a.

[0019] As in Fig. As shown in Figure 2, the heat exchanger 100 includes a downstream heat exchanger unit 100_1 and an upstream heat exchanger unit 100_2. The downstream heat exchanger unit 100_1 is arranged downstream in the air flow direction. The upstream heat exchanger unit 100_2 is arranged further upstream in the air flow direction than the downstream heat exchanger unit 100_1.

[0020] The downstream heat exchanger unit 100_1 includes a downstream heat transfer tube row 1_1 with heat transfer tubes 1 arranged and spaced apart in a direction crossing the air flow direction, and a first header 21 connected to a lower end portion of the downstream heat transfer tube row 1_1. The first header 21 distributes the refrigerant in the heat transfer tubes of the downstream heat transfer tube row 1_1 or causes portions of the refrigerant flowing out of the downstream heat transfer tube row 1_1 to mix with each other. The heat transfer tubes 1 of the downstream heat transfer tube row 1_1 enable vertical refrigerant flow.

[0021] The upstream heat exchanger unit 100_2 includes an upstream heat transfer tube row 1_2 with heat transfer tubes 1 arranged and spaced apart in a direction that crosses the air flow direction, and a second header 22 connected to a lower end portion of the upstream heat transfer tube row 1_2. The second header 22 distributes refrigerant in the heat transfer tubes of the upstream heat transfer tube row 1_2 or causes portions of the refrigerant flowing out of the upstream heat transfer tube row 1_2 to mix with each other. The heat transfer tubes 1 of the upstream heat transfer tube row 1_2 enable vertical refrigerant flow.

[0022] The downstream heat exchanger unit 100_1 and the upstream heat exchanger unit 100_2 share a common header 23, which is connected to an upper end portion of the downstream heat tube row 1_1 and an upper end portion of the upstream heat tube row 1_2, and connects the downstream heat tube row 1_1 and the upstream heat tube row 1_2. The common header 23 allows the refrigerant to move in the row direction between the downstream heat tube row 1_1 and the upstream heat tube row 1_2.

[0023] Here, the air flow direction and the flow direction of the refrigerant are defined as follows. The air flow direction is defined as a direction from left to right in the figure. The refrigerant in the first header 21 flows through the downstream heat transfer tube row 1_1 into the common header 23. The refrigerant that has flowed into the common header 23 moves in the row direction of the heat exchanger 100 and flows into the upstream heat transfer tube row 1_2. The refrigerant that has flowed into the upstream heat transfer tube row 1_2 flows into the second header 22. In this case, the flow of the refrigerant is directed from right to left in the figure, that is, in a direction opposite to the air flow direction. At this point, the flow of the refrigerant is defined as flowing against the air flow direction.

[0024] In the case where the air flow direction is from left to right in the figure, the refrigerant in the second header 22 flows into the upstream heat transfer tube row 1_2. The refrigerant that has flowed into the upstream heat transfer tube row 1_2 moves in the row toward the common header 23 and flows through the downstream heat transfer tube row 1_1 into the first header 21. In this case, the refrigerant flows from left to right in the figure, that is, in the same direction as the air flow direction. At this point, the flow of the refrigerant is defined as being parallel to the air flow direction.

[0025] Fig. 3 shows a state of flow of the refrigerant in the heat exchanger 100 according to Embodiment 1. Fig. 3 shows a state of the flow of the refrigerant when the refrigerant that has flowed into the first header 21 flows out of the second header 22. In Fig. 3, the arrows indicate the flow of refrigerant, and the hollow arrow indicates the air flow direction.

[0026] When the heat exchanger 100 according to Embodiment 1 functions as a condenser, the downstream heat exchanger row 1_1 and the upstream heat exchanger row 1_2 include a first region R1, a second region R2, and a third region R3.

[0027] The first region R1 is a region where the refrigerant that has flowed into the first header 21 flows against the air flow direction and into the second header 22. The second region R2 is a region where the refrigerant that has passed through the first region R1 and flowed into the second header 22 flows parallel to the air flow direction and into the first header 21. The third region R3 is a region where the refrigerant that has passed through the second region R2 and flowed into the first header 21 flows against the air flow direction and into the second header 22.

[0028] How Fig. 3, the first header 21 includes a first header 21_1 in the first region R1, a first header 21_2 in the second region R2, and a first header 21_3 in the third region R3. The second header 22 includes a second header 22_1 in the first region R1, a second header 22_2 in the second region R2, and a second header 22_3 in the third region R3. The common header 23 includes a common header 23_1 in the first region R1, a common header 23_2 in the second region R2, and a common header 23_3 in the third region R3.

[0029] The first headpiece 21, the second headpiece 22 and the common headpiece 23 are in Fig. 3 are each divided into three parts, but do not necessarily have to be divided into three parts. For example, a partition plate provided within a headpiece can divide the interior of one headpiece into several sections.

[0030] In Fig. 3, the first region R1, the second region R2, and the third region R3 are connected in series by connecting pipes 4. In particular, the second header 22_1 is connected in series to the second header 22_2 by the connecting pipe 4. The first header 21_2 is connected in series to the first header 21_3 by the connecting pipe 4.

[0031] It should be noted that the first region R1, the second region R2 and the third region R3 can be separated from each other by partition plates in the first header 21, the second header 22 and the common header 23.

[0032] In Fig. 3, the length of the downstream heat exchanger unit 100_1 in the first region R1 in the longitudinal direction of the first header 21_1 and the length of the upstream heat exchanger unit 100_2 in the first region R1 in the longitudinal direction of the second header 22_1 are each defined as L1. The length of the downstream heat exchanger unit 100_1 in the second region R2 in the longitudinal direction of the first header 21_2 and the length of the upstream heat exchanger unit 100_2 in the second region R2 in the longitudinal direction of the second header 22_2 are each defined as L2. The length of the downstream heat exchanger 100_1 in the third region R3 in the longitudinal direction of the first header 21_3 and the length of the upstream heat exchanger 100_2 in the third region R3 in the longitudinal direction of the second header 22_3 are each defined as L3.

[0033] In Fig. 3 a point A, a point B and a point C correspond to a point A, a point B and a point C in Fig. 4, which will be described later.

[0034] Fig. 4 shows a state of the refrigerant flowing in the heat exchanger 100 according to Embodiment 1. In Fig. 4, the vertical axis represents the temperature T and the horizontal axis the entropy S. In addition, the arrow in Fig. 4 shows the direction of change of the refrigerant when the heat exchanger 100 acts as a condenser.

[0035] When the heat exchanger 100 functions as a condenser, the refrigerant typically first flows into the heat exchanger 100 in a superheated gas state, is brought into a two-phase gas-liquid state, and then into a subcooled liquid state, and then flows out. At this time, a region where the refrigerant is the superheated gas is defined as region X, a region where the refrigerant is in the two-phase gas-liquid state is defined as region Y, and a region where the refrigerant is in the subcooled liquid state is defined as region Z.

[0036] In embodiment 1, L1, L2 and L3 are in Fig. 3 so that the states of the refrigerant at points A, B and C in Fig. 4 at points A, B and C in Fig. 3. Here, point A represents the temperature T and the entropy S immediately before the refrigerant flows into region X. Point B represents the temperature T and the entropy S immediately before the refrigerant flows out of region Y and immediately before the refrigerant flows into the third region R3. Point C represents the temperature T and the entropy S immediately after the refrigerant has flowed out of region Z.

[0037] L1 is preferably determined so that the refrigerant in the form of superheated gas flowing in the region X flows within the first header 21_1 and the second header 22_1. L3 is preferably determined so that the refrigerant in the form of subcooled liquid flowing in the region Z flows within the first header 21_3 and the second header 22_3. In the heat exchanger 100 of Embodiment 1, L1, L2, and L3 are set so that the refrigerant flows in the region X and the region Y, where the refrigerant temperature changes, each form a countercurrent to the air flow direction.

[0038] Region X and region Z are each a sensible heat region. The sensible heat region is a region where the temperature of the refrigerant changes due to heat exchange in the heat exchanger 100. Region Y is a latent heat region where the temperature of the refrigerant does not change even with heat exchange in the heat exchanger 100. When heat exchange is equal, a larger temperature difference is required in the sensible heat region compared to the latent heat region; therefore, the refrigerant in the heat exchanger 100 is caused to flow against the air flow direction in the first region R1 and the third region R3, which are latent heat regions. This improves the heat exchange performance.

[0039] The refrigerant flowing in the first zone R1 contains the superheated gas, the refrigerant flowing in the second zone R2 is the two-phase gas-liquid refrigerant, and the refrigerant flowing in the third zone R3 contains the subcooled liquid.

[0040] When using a mixed refrigerant, the temperature also changes in the second region R2, where the two-phase gas-liquid refrigerant flows, even when the heat exchanger 100 functions as an evaporator. When the heat exchanger 100 functions as an evaporator, the two-phase gas-liquid refrigerant flows into the evaporator and passes through it to be converted into a single-phase gas. Even when the heat exchanger 100 functions as an evaporator, for example, by using a variable path, the heat exchanger 100 can be configured so that the refrigerant also flows in countercurrent, parallel current, and countercurrent to the air flow direction, as in the case of the condenser. Thus, the evaporation performance of the heat exchanger 100 can also be improved.

[0041] According to Embodiment 1, when the heat exchanger 100 functions as a condenser, the heat exchanger 100 can be provided in which, unlike the prior art, the refrigerant flows against the air flow direction in the first region R1, which is a superheated gas region, in addition to the third region R3, which is a subcooled liquid region. In the second region R2, which is the latent heat region where sufficient heat exchange is achieved even at a small temperature difference, the two-phase gas-liquid refrigerant is caused to flow parallel to the air flow direction. As described above, the refrigerant is caused to flow against the air flow direction when it is in the subcooled liquid state and the superheated gas state, that is, in the sensible heat regions where a large temperature difference is required.This improves the heat exchange performance of the heat exchanger 100. Embodiment 2

[0042] Fig. 5 shows a state of flow of refrigerant in a heat exchanger 100 of an air conditioning apparatus 300 according to Embodiment 2. Fig. 5 shows a state of the refrigerant flow when the refrigerant that has flowed into a first header 21 flows out of a second header 22. In Fig. 5, the arrows indicate the refrigerant flow, and the hollow arrow indicates the air flow direction.

[0043] Fig. Fig. 6 shows an arrangement of first headers 21 and second headers 22 of the heat exchanger 100 in the air conditioning device 300 according to embodiment 2. A common header 23 and heat transfer tubes 1 are shown in Fig. 5, but are omitted and are shown in Fig. 6 not shown. In Fig. 6, the arrows indicate the flow of the refrigerant and the hollow arrows indicate the air flow direction.

[0044] As an example of the three-zone heat exchanger 100, the heat exchanger 100 having two heat exchangers, namely, a first heat exchanger 11 and a second heat exchanger 12, is given in Embodiment 2. The first heat exchanger 11 includes a first header 21_1, a second header 22_1, a common header 23_1, a first header 21_2, a second header 22_2, and a common header 23_2, as well as heat transfer tubes 1 connected to these headers. In addition, the second heat exchanger 12 includes a first header 21_3, a second header 22_3, and a common header 23_3, as well as heat transfer tubes 1 connected to these headers.

[0045] As in Fig. 6, an outdoor unit casing 7 contains a fan 5, a compressor 6, the first heat exchanger 11 and the second heat exchanger 12.

[0046] The outdoor unit casing 7 is a side-flow casing with a rectangular footprint. The compressor 6 compresses the refrigerant and releases the high-pressure gaseous refrigerant. The fan 5 directs the air to the first heat exchanger 11 and the second heat exchanger 12 for heat exchange.

[0047] The first heat exchanger 11 and the second heat exchanger 12 are arranged in an L-shape so that the first heat exchanger 11 and the second heat exchanger 12 surround the fan 5.

[0048] As in Fig. As shown in Figure 6, the first heat exchanger 11 includes a first region R1 and a second region R2. The second heat exchanger 12 includes a third region R3.

[0049] The first heat exchanger 11 includes the first header 21_1 in the first region R1 and the first header 21_2 in the second region R2. A partition plate 3 is provided between the first header 21_1 and the first header 21_2, separating the first region R1 and the second region R2 from each other.

[0050] As in Fig. As shown in Figure 5, the first heat exchanger 11 also includes the common header 23_1 in the first region R1 and the common header 23_2 in the second region R2. A partition plate 3 is provided between the common header 23_1 and the common header 23_2, separating the first region R1 and the second region R2 from each other.

[0051] The second heat exchanger 12 includes the third region R3. The second heat exchanger 12 includes the first header 21_3 in the third region R3, the second header 22_3 in the third region R3, and the common header 23_3 in the third region R3.

[0052] The third region R3 is a region where the subcooled liquid flows, and if the longitudinal length L3 of the heat exchange units in the third region R3 is set excessively large, the refrigerant in the form of superheated gas may even flow into the second region R2. In this case, an effect of improving heat exchange performance due to the flow of the refrigerant being against the air flow direction in the first region R1 is reduced. Moreover, a reduction in a region into which the superheated gas refrigerant and the gas-liquid two-phase refrigerant flow, whose pressure losses are larger than those of the subcooled liquid refrigerant, leads to an increase in pressure loss, resulting in a reduction in heat exchange performance.

[0053] In Embodiment 2, (L1 + L2) / 2 > L3 holds when L1 is the longitudinal length of the first region R1, L2 is the longitudinal length of the second region R2, and L3 is the longitudinal length of the third region R3. The sum of the longitudinal length L1 of the heat exchanger units in the first region R1 and the longitudinal length L2 of the heat exchanger units in the second region R2 in the first heat exchanger 11 is greater than the longitudinal length L3 of the heat exchanger units in the third region R3 in the second heat exchanger 12. Furthermore, L2 > L1 holds in Embodiment 2.

[0054] The first header 21_1 has a refrigerant inlet 21_1_A through which refrigerant flows in. The first header 21_2 has a refrigerant outlet 21_2_B through which the refrigerant flowing in through the refrigerant inlet 21_1_A flows out.

[0055] The first header 21_3 has a refrigerant inlet 21_3_A through which the refrigerant that has flowed out through the refrigerant outlet 21_2_B flows in. The second header 22_3 has a refrigerant outlet 22_3_B through which the refrigerant flows out.

[0056] The refrigerant outlet 21_2_B and the refrigerant inlet 22_3_A are connected by a connecting pipe 4. The refrigerant inlet 21_3_A is located in a region of the first header 21_3 in the third region R3, which is further away from the refrigerant outlet 21_2_B than the other region of the first header 21_3.

[0057] The refrigerant that has flowed through the refrigerant inlet 21_1_A of the first header 21_1 into the first heat exchanger 11 first flows against the air flow direction in the first region R1. The refrigerant that has flowed through the first region R1 flows into the second header 22 in the first region R1 and flows parallel to the air flow direction in the second region R2.

[0058] The refrigerant that has flowed through the second region R2 flows into the first header 21_2 and flows out through the refrigerant outlet 21_2_B. The refrigerant that has flowed out through the refrigerant outlet 21_2_B then flows through the connecting pipe 4 and flows into the refrigerant inlet 21_3_A of the first header 21_3 in the third region R3 of the second heat exchanger 12.

[0059] The refrigerant that has flowed into the refrigerant inlet 21_3_A flows against the air flow direction in the third region R3 and flows out of the second heat exchanger 12.

[0060] Note that the heat exchanger 100 of Embodiment 2 is also applicable to a casing other than the side-flow casing. For example, in a top-flow outdoor unit casing 7 in which the air drawn through one side of the casing is discharged from an upper portion of the casing, a plurality of heat exchangers 100 may be arranged on four sides so that the plurality of heat exchangers 100 surround the fan 5.

[0061] Fig. Fig. 7 shows a state in which two heat exchangers 100_A and 100_B according to Embodiment 2 are arranged on four sides in the outdoor unit casing 7 so that the heat exchangers 100_A and 100_B surround the fan 5. In Fig. 7 are the common headpiece 23 and the Fig. 5, the heat transfer tubes 1 are omitted and not shown. In Fig. 7, the arrows indicate the flow of the refrigerant and the hollow arrows indicate the air flow direction.

[0062] As in Fig. As shown in Figure 7, two heat exchangers 100_A and 100_B are provided, each including the first heat exchanger 11 and the second heat exchanger 12. The heat exchanger 100_A and the heat exchanger 100_B are arranged such that the fan 5 is surrounded by the heat exchanger 100_A and the heat exchanger 100_B.

[0063] As in Fig. 6, the first heat exchanger 11 and the second heat exchanger 12 of the heat exchanger 100_A are arranged in an L-shape so that the first heat exchanger 11 and the second heat exchanger 12 surround the fan 5. The first heat exchanger 11 and the second heat exchanger 12 of the heat exchanger 100_B are arranged in an L-shape so that the first heat exchanger 11 and the second heat exchanger 12 surround the fan 5. <Vorteilhafte Effekte>

[0064] In the heat exchanger 100 of Embodiment 2, the first region R1 and the second region R2 are included in a first heat exchanger 11, which can save space; whereby the heat transfer area can be further increased.

[0065] Additionally, in the heat exchanger 100 of Embodiment 2, the first heat exchanger 11 includes the first region R1 and the second region R2. That is, as an example of a method for switching the refrigerant flows from countercurrent to parallel current against or to the air flowing into the heat exchanger 100, a method is used in which the partition plate 3 is used to partition the interior of the first header 21. Thus, the refrigerant flow reversal can be achieved with minimal impact on the structure of the heat exchanger 100, and the manufacturing cost can be kept low.

[0066] When a region at the end of the header of the first heat exchanger 11 and a region at the end of the header of the second heat exchanger 12, which are close to each other, are connected by the connecting pipe 4, structural limitations such as pressure loss and bending angle are likely to have an influence. When attempting to connect the headers of the first heat exchanger 11 and the second heat exchanger 12, which are close to each other, the pressure loss increases if the headers are connected by bending the connecting pipe 4 at an acute angle. In addition, since a certain bending radius cannot be exceeded depending on the diameter of the connecting pipe 4, or a component for connecting the connecting pipe 4 is attached to a region at the end of the header, the distance between the first heat exchanger 11 and the second heat exchanger 12 increases.This enlarges the casing equipped with the heat exchanger 100, including the first heat exchanger 11 and the second heat exchanger 12.

[0067] Furthermore, attempting to install the heat exchanger 100 including the first heat exchanger 11 and the second heat exchanger 12 without changing the size of the housing results in a reduction in the heat transfer area of ​​the heat exchanger 100 due to structural limitations, such as piping. This reduces the mounting area of ​​the heat exchanger 100 and reduces the performance of the heat exchanger.

[0068] In the heat exchanger 100 of Embodiment 2, the refrigerant outlet 21_2_B and the refrigerant inlet 21_3_A are connected by the connecting pipe 4. The refrigerant inlet 21_3_A is provided in one region of the first header 21_3 in the third region R3, which is farther away from the refrigerant outlet 21_2_B than the other region of the first header 21_3.

[0069] Thus, the arrangement with the maximum possible heat transfer area of ​​the first heat exchanger 11 and the second heat exchanger 12 can be manufactured, the mounting area of ​​the heat exchanger 100 can be increased, and thus an improvement in heat exchange performance can be expected. As a result, by incorporating the heat exchanger 100 of Embodiment 2, the heat exchanger 100 can maximize its capabilities. Embodiment 3

[0070] Fig. Fig. 8 shows a state in which a heat exchanger 100 according to Embodiment 3 is arranged in an outdoor unit casing 7. The outdoor unit casing 7 is a top-flow type casing. In Fig. 8 is a common headpiece 23, which corresponds to the Fig. 5, is omitted and not shown. In Fig. 8, the arrows indicate the flow of the refrigerant and the hollow arrows indicate the air flow direction.

[0071] As in Fig. 8, the heat exchanger 100 according to Embodiment 3 includes a first heat exchanger 11, a second heat exchanger 12, and a third heat exchanger 13. The first heat exchanger 11, the second heat exchanger 12, and the third heat exchanger 13 are arranged in a U-shape so that the first heat exchanger 11, the second heat exchanger 12, and the third heat exchanger 13 surround a fan 5.

[0072] The first heat exchanger 11 includes a first region R1, and the refrigerant flows countercurrently to the air flow direction. The second heat exchanger 12 includes a second region R2, and the refrigerant flows parallel to the air flow direction. The third heat exchanger 13 includes a third region R3, and the refrigerant flows countercurrently to the air flow direction.

[0073] A second header 22_1 in the first region R1 on the upstream side of the first heat exchanger 11 is connected via a connecting pipe 4 to a second header 22_2 in the second region R2 on the upstream side of the second heat exchanger 12. A first header 21_2 in the second region R2 on the downstream side of the second heat exchanger 12 is connected to a first header 21_3 in the third region R3 on the downstream side of the third heat exchanger 13 by a connecting pipe 4.

[0074] The connection between the first heat exchanger 11 and the second heat exchanger 12 is achieved by connecting the second header 22_1 on the outside to the second header 22_2 on the outside through the connecting pipe 4. The connection between the second heat exchanger 12 and the third heat exchanger 13 is established by connecting the first header 21_2 on the inside to the first header 21_3 on the inside through the connecting pipe 4.

[0075] That is, when the first heat exchanger 11 in which the refrigerant flows in countercurrent and the second heat exchanger 12 in which the refrigerant flows in parallel current are connected by the connecting pipe 4, the second header 22_1 on the outside and the second header 22_2 on the outside are connected in the second region R2.

[0076] When the second heat exchanger 12 in which the refrigerant flows in a parallel flow and the third heat exchanger 13 in which the refrigerant flows in counterflow are connected by the connecting pipe 4, the first header 21_2 on the inside and the first header 21_3 on the inside are connected.

[0077] When connecting the headers on the inside of the housing, some space is required if the connection is made by bending the pipe, as in the case where the headers are connected on the outside. As in Fig.As shown in Figure 8, a refrigerant inlet 21_3_A is provided in a portion of the first header 21_3 in the third region R3 that is farther from a refrigerant outlet 21_2_B than the other portion of the first header 21_3. Thus, in the heat exchanger 100 of Embodiment 3, space saving of the heat exchanger 100 can be achieved, and thus, improvement in heat exchange performance and optimization of the mounting area can be expected.

[0078] The embodiments are provided as examples and are not intended to limit the scope of the claims. The embodiments may be implemented in various other forms, and various omissions, substitutions, and changes may be made without departing from the gist of the embodiments. The embodiments and their modifications are included within the scope and gist of the embodiments. List of reference symbols 1 heat transfer tube 1_1 Row of upstream heat transfer tubes 1_2 Row of upstream heat transfer tubes 3 dividing plate 4 connecting pipe 5 Fan 6 compressors 7 Outdoor unit housing 8 Expansion valve 11 first heat exchanger 12 second heat exchanger 13 third heat exchanger 21 first headpiece 21_1 first headpiece in the first area 21_1_A Coolant inlet 21_2 first headpiece in the second area 21_2_B Coolant outlet 21_3 first headpiece in the third area 21_3_A Coolant inlet 22 second headpiece 22_1 second headpiece in the first area 22_2 second headpiece in the second area 22_3 second headpiece in the third area 22_3_B Refrigerant outlet 23 common headpiece 23_1 common headpiece in the first area 23_2 common headpiece in the second area 23_3 common headpiece in the third area 100, 100_A, 100_B heat exchangers 100_1 downstream heat exchanger unit 100_2 upstream heat exchanger unit 100a condenser 100b evaporator 110 Refrigerant circuit 300 air conditioning unit R1 first area R2 second area R3 third area L1 Length of the heat exchanger unit in the first area in longitudinal direction L2 Length of the heat exchanger unit in the second area in the longitudinal direction L3 Length of the heat exchanger unit in the third area in longitudinal direction T Temperature S Entropy QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] JP 7-98 162 A

[0003]

Claims

[1] Heat exchanger comprising: a downstream heat exchanger unit arranged downstream in an air flow direction; an upstream heat exchanger unit arranged further upstream than the downstream heat exchanger unit in the air flow direction; and a common headpiece, wherein the downstream heat exchanger unit comprises a downstream heat transfer tube row having heat transfer tubes arranged and spaced apart in a direction crossing the air flow direction, and a first header connected to a lower end portion of the downstream heat transfer tube row, wherein the upstream heat exchanger unit comprising an upstream heat transfer tube row having heat transfer tubes arranged and spaced apart in a direction crossing the air flow direction, and a second header connected to a lower end portion of the upstream heat transfer tube row, wherein the common header is connected to an upper region of the downstream heat transfer tube row and an upper region of the upstream heat transfer tube row and connects the downstream heat transfer tube row and the upstream heat transfer tube row when the downstream heat exchanger unit and the upstream heat exchanger unit each function as a condenser, wherein the downstream heat exchanger unit and the upstream heat exchanger unit have a first region in which the refrigerant flowing into the first header flows counter to the air flow direction and flows into the second header, have a second region in which the refrigerant flowing through the first region and flowing into the second header flows parallel to the air flow direction and flows into the first header, and have a third region in which the refrigerant flowing through the second region and into the first header flows against the air flow direction and into the second header. [2] The heat exchanger according to claim 1, wherein when the length of the downstream heat exchanger unit in the first region in the longitudinal direction of the first header and the length of the upstream heat exchanger unit in the first region in the longitudinal direction of the second header are each defined as L1, the length of the downstream heat exchanger unit in the second region in the longitudinal direction of the first header and the length of the upstream heat exchanger unit in the second region in the longitudinal direction of the second header are each defined as L2, and the length of the downstream heat exchanger unit in the third region in the longitudinal direction of the first header and the length of the upstream heat exchanger unit in the third region in the longitudinal direction of the second header are each defined as L3, the following holds: (L1 + L2) / 2 > L3. [3] Heat exchanger according to claim 2, wherein: L2 > L1. [4] Heat exchanger according to one of claims 1 to 3, wherein the common header and the first header each include a partition plate separating the first region and the second region from each other. [5] Heat exchanger according to one of claims 1 to 4, wherein the downstream heat exchanger unit and the upstream heat exchanger unit are each divided into a first heat exchanger including the first region and the second region, and a second heat exchanger containing the third area, wherein the first header of the first heat exchanger has a refrigerant outlet through which the refrigerant flows out, wherein the first header of the second heat exchanger has a refrigerant inlet through which the refrigerant flowing out through the refrigerant outlet flows in, wherein the heat exchanger further includes a connecting pipe connecting the refrigerant outlet and the refrigerant inlet, wherein the first heat exchanger and the second heat exchanger are arranged in an L-shape in plan view and wherein the refrigerant inlet is provided in a region of the first header that is farther from the refrigerant outlet than the other region of the first header. [6] A heat exchanger according to any one of claims 1 to 5, wherein the refrigerant flowing in the first region contains superheated gas and the refrigerant flowing in the third region contains subcooled liquid. [7] Heat exchanger comprising: a sidestream housing containing the heat exchanger according to any one of claims 1 to 6. [8] Heat exchanger comprising: a top flow housing incorporating the heat exchanger according to any one of claims 1 to 6. [9] Cooling circuit device comprising: the heat exchanger according to one of claims 1 to 8.

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