Air conditioner

Abstract

To provide an air conditioner capable of improving heat exchange performance of a heat exchanger in cooling operation and heating operation.SOLUTION: An outdoor heat exchanger 200 that has a plurality of rows constituted by a plurality of heat transfer pipes and performs heat exchange by causing a refrigerant to flow through each of a plurality of refrigerant flow paths formed by connecting the heat transfer pipes, a distributor 24 that merges the plurality of refrigerant flow paths in a case where the outdoor heat exchanger 200 acts as a condenser, and a subcooler 201 that has a refrigerant flow path constituted by connecting the plurality of rows of heat transfer pipes constituting the outdoor heat exchanger 200, the subcooler 201 is provided on the downstream side of the distributor 24 in the direction in which the refrigerant flows when the outdoor heat exchanger 200 acts as a condenser.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an air conditioner that achieves improved heat exchange efficiency during both cooling and heating. [Background technology]

[0002] Air conditioners are required to achieve improved performance both during cooling operation and heating operation.

[0003] One method for improving the performance of an air conditioner is, for example, to increase the heat transfer coefficient by increasing the refrigerant flow velocity. Large air conditioners, such as multi-air conditioners for buildings, maximize the use of large heat exchangers by dividing the refrigerant flow paths into multiple paths. However, dividing the paths reduces the amount of refrigerant per path, slowing the refrigerant flow velocity and reducing the heat transfer coefficient. The performance degradation associated with the reduced heat transfer coefficient is particularly pronounced when operating with a low refrigerant circulation volume (for example, during cooling operation, which is an intermediate condition (output of about 50% of the rated output)).

[0004] The total amount of refrigerant circulating through the refrigeration cycle of an air conditioner also affects its operating performance. However, the amount of refrigerant that provides peak performance during cooling operation differs from the amount of refrigerant that provides peak performance during heating operation. Therefore, charging an appropriate amount of refrigerant for one operation may result in reduced performance during the other operation. Because cooling operation has a greater impact on the performance of an air conditioner, the amount of refrigerant charged is generally determined based on the cooling operation. Therefore, during heating operation, the amount of refrigerant becomes excessive, resulting in excessive subcooling of the refrigerant, resulting in reduced operating performance.

[0005] Here, Japanese Patent Laid-Open Publication No. 2018-136121 (Patent Document 1) discloses a configuration in which a sub-cooler is provided in a heat exchanger. According to Patent Document 1, it is possible to improve the performance of the heat exchanger and provide a high-performance air conditioner.

[0006] However, in Patent Document 1, only the first row of heat transfer tubes in the heat exchanger is configured as a sub-cooler. Therefore, it is difficult to improve the heat transfer coefficient, especially during medium output cooling operation, and the effect of improving performance is limited. Furthermore, because only the first row of heat transfer tubes in the heat exchanger is configured as a sub-cooler, excess refrigerant cannot be stored during heating operation, which can also result in a decrease in operating performance.

[0007] Therefore, there was a need for further technology that could improve performance in both cooling and heating modes. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2018-136121 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in view of the problems in the prior art described above, and has an object to provide an air conditioner that improves the heat exchange performance of a heat exchanger during cooling operation and heating operation. [Means for solving the problem]

[0010] That is, according to the present invention, a heat exchanger having a plurality of rows each composed of a plurality of heat transfer tubes, and exchanging heat by passing a refrigerant through a plurality of refrigerant flow paths each formed by connecting the heat transfer tubes; a pipe that joins the plurality of refrigerant flow paths when the heat exchanger functions as a condenser; a subcooler having a refrigerant flow path formed by connecting a plurality of rows of heat transfer tubes constituting the heat exchanger; Including, the subcooler is provided downstream of the piping in a direction in which the refrigerant flows when the heat exchanger functions as a condenser. An air conditioning system is provided. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide an air conditioner that improves the heat exchange performance of a heat exchanger during cooling operation and heating operation. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view showing a typical heat exchanger. [Figure 2] FIG. 2 is a diagram illustrating a refrigeration cycle in the air conditioning apparatus. [Figure 3] FIG. 4 is a diagram illustrating an example of the relationship between the total amount of refrigerant sealed in the refrigeration cycle and the efficiency of the air conditioner. [Figure 4] FIG. 2 is a diagram showing the configuration of an outdoor heat exchanger including a sub-cooler in the present embodiment. [Figure 5] 3 is a diagram showing the configuration of an outdoor heat exchanger having a plurality of refrigerant flow paths configured as a sub-cooler in the present embodiment; FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will be described below with reference to embodiments, but the present invention is not limited to the embodiments described below. In the drawings referred to below, the same reference numerals will be used for common elements, and their description will be omitted as appropriate.

[0014] Fig. 1 is a perspective view showing a typical heat exchanger 100. Fig. 1(A) shows a heat exchange section 100' composed of a plurality of heat transfer tubes 101 and a plurality of fins 102, and Fig. 1(B) shows a heat exchanger 100 configured such that the heat transfer tubes 101 of the heat exchange section 100' are connected with joints 103.

[0015] As shown in FIG. 1A, the heat exchange section 100′ of the heat exchanger 100 includes a plurality of heat transfer tubes 101 through which a refrigerant flows in the x-axis direction. FIG. 1A illustrates an example of a heat exchange section 100′ configured with eight rows of heat transfer tubes 101 arranged at equal intervals in the z-axis direction, and three rows arranged in the y-axis direction. In the following description, the rows of heat transfer tubes 101 are referred to as the “first row,” “second row,” and “third row” from the front to the back in the y-axis direction. The heat transfer tubes 101 in the second row are offset in the z-axis direction by half the pitch of the arrangement interval of the heat transfer tubes 101 relative to the heat transfer tubes 101 in the first and third rows, forming a so-called “staggered arrangement.” This allows the air flow passing through the heat exchange section 100′ to meander, and intake air that experiences little temperature change due to heat exchange in the previous row is guided around the heat transfer tubes in the next row, thereby improving heat exchange efficiency.

[0016] The fins 102 are arranged at equal intervals in the x-axis direction and are in contact with the heat transfer tubes 101. This allows heat exchange between the air passing between the fins 102 and the refrigerant flowing inside the heat transfer tubes 101.

[0017] As shown in FIG. 1(B), the heat exchanger 100 is configured by connecting the heat transfer tubes 101 of the heat exchange section 100' shown in FIG. 1(A) with joints 103. In the heat exchanger 100, the heat transfer tubes 101 on the far side in the x-axis direction are also connected with joints 103. The heat transfer tube 101 in the lowest row of the first row is connected to a liquid refrigerant pipe, and the heat transfer tube 101 in the highest row of the third row is connected to a gas refrigerant pipe. This forms a refrigerant flow path, allowing the refrigerant to pass through each heat transfer tube 101 of the heat exchanger 100 while reciprocating in the x-axis direction.

[0018] The joint 103 is a connecting pipe that connects to the heat transfer pipe 101 and can change the direction of refrigerant flow. The joint 103 can be selected from various shapes depending on the application, and for example, a U-shape, an elbow shape, a trifurcated shape, etc. can be used.

[0019] In the following description, for convenience, both ends of the heat transfer tube 101 will be distinguished from one another and the structure of the heat exchanger 100 will be described by referring to the front side in the x-axis direction as the "front surface" of the heat exchanger 100 and the rear side in the x-axis direction as the "rear surface" of the heat exchanger 100. That is, in Figures 1(A) and 1(B), the surface on which the ends of the heat transfer tube 101 and the joints 103 are visible will be described as the "front surface."

[0020] The direction of refrigerant flow is reversed depending on whether the heat exchanger 100 functions as an evaporator or a condenser. When the heat exchanger 100 functions as an evaporator, liquid refrigerant flows in from the lowest heat transfer tube 101 in the first row connected to the liquid refrigerant pipe, passes through each heat transfer tube 101 to exchange heat, and flows out from the top heat transfer tube 101 in the third row to the gas refrigerant pipe. When the heat exchanger 100 functions as a condenser, gas refrigerant flows in from the top heat transfer tube 101 in the third row connected to the gas refrigerant pipe, passes through each heat transfer tube 101 to exchange heat, and flows out from the bottom heat transfer tube 101 in the first row to the liquid refrigerant pipe.

[0021] The present invention will be described below based on the structure of a general heat exchanger 100 shown in Fig. 1, but is not intended to limit the embodiment in any way. Therefore, the number, arrangement, number of stages, number of rows, etc. of heat transfer tubes 101 included in the heat exchanger 100 are not limited to those shown in Fig. 1 and may be arbitrary.

[0022] Next, the refrigeration cycle will be explained. Fig. 2 is a diagram illustrating the refrigeration cycle in the air conditioner 1. The air conditioner 1 is composed of an outdoor unit 2 and an indoor unit 3. In the air conditioner 1 shown in Fig. 2, the outdoor unit 2 is installed outside the building, and the indoor unit 3 is installed inside the room to be air-conditioned. The outdoor unit 2 and the indoor unit 3 are connected via refrigerant piping 4 through which a refrigerant flows. The refrigerant piping 4 includes a gas refrigerant piping 4G through which a gaseous refrigerant (gas refrigerant) flows, and a liquid refrigerant piping 4L through which a liquid refrigerant (liquid refrigerant) flows.

[0023] The outdoor unit 2 includes a four-way valve 20, a tank (accumulator) 27, a compressor 21, a gas header 22, a blower fan 23, an outdoor heat exchanger 200, a liquid-side distribution pipe 28, a distributor 24, an expansion valve 25, a liquid check valve 26, and a gas check valve 29. The compressor 21 compresses gas refrigerant in a low-temperature, low-pressure state, changing it into gas in a high-temperature, high-pressure state. The gas header 22 distributes the gas refrigerant in one flow path to multiple flow paths, or combines the gas refrigerant in multiple flow paths into one flow path. The number of branches in the gas header 22 is not limited to the number shown in FIG. 2 and can be any number.

[0024] The outdoor heat exchanger 200 exchanges heat between the refrigerant and the outdoor air. The outdoor heat exchanger 200 acts as a condenser when the air conditioner 1 is in cooling operation. In one embodiment of the present invention, which will be described later, a part of the outdoor heat exchanger 200 can be used as a sub-cooler 201. The outdoor unit 2 of this embodiment is configured as a so-called top-flow type (top-blowing type) outdoor unit, and a blower fan 23 is provided above the outdoor heat exchanger 200.

[0025] The blower fan 23 blows outside air through the outdoor heat exchanger 200. The liquid distribution pipe 28 and distributor 24 distribute the liquid refrigerant from one flow path to multiple flow paths, or combine the liquid refrigerant from multiple flow paths into one flow path. The number of branches in the liquid distribution pipe 28 and distributor 24 is not limited to the number shown in Figure 2 and can be any number. The expansion valve 25 is controlled to a fully open state during cooling, allowing the refrigerant to pass through as is, but during heating, it decompresses the refrigerant to control the evaporation pressure and the evaporator outlet state. The liquid check valve 26, together with the gas check valve 29, is used in a closed state when checking the airtightness of the piping and indoor unit parts during installation or when vacuuming, and is operated in a fully open state after installation is completed, allowing the refrigerant to pass through as is during operation.

[0026] The indoor unit 3 is equipped with an expansion valve 31, a distributor 32, a liquid side distribution pipe 35, an indoor heat exchanger 300, a gas header 33, and a blower fan 34. Note that the expansion valve 31, the distributor 32, the gas header 33, and the blower fan 34 are the same as those described for the outdoor unit 2, and therefore description thereof will be omitted. The indoor heat exchanger 300 exchanges heat between the refrigerant and the indoor air. Note that the indoor heat exchanger 300 acts as an evaporator when the air conditioner 1 is in cooling operation.

[0027] The refrigerant piping 4 is a piping that transfers refrigerant between the indoor unit 3 and the outdoor unit 2. The gas check valve 29 of the outdoor unit 2 and the gas header 33 of the indoor unit 3 are connected by gas refrigerant piping 4G. The liquid check valve 26 of the outdoor unit 2 and the expansion valve 31 of the indoor unit 3 are connected by liquid refrigerant piping 4L. In FIG. 2, the solid arrows along the refrigerant piping 4G, 4L indicate the direction of refrigerant movement when the air conditioner 1 is performing cooling operation. The direction of refrigerant movement can be reversed by the four-way valve 20, allowing switching between cooling operation and heating operation.

[0028] Below, the refrigeration cycle of the air conditioner 1 will be explained using the cooling operation as an example. Note that in heating operation, the flow of refrigerant is reversed by switching the four-way valve 20, and the functions of the indoor heat exchanger and the outdoor heat exchanger are reversed, but other operations are similar, so detailed explanations will be omitted here.

[0029] The compressor 21 compresses gas refrigerant in a low-temperature, low-pressure state, changes it to a high-temperature, high-pressure state, and discharges it. The gas refrigerant discharged from the compressor 21 passes through the four-way valve 20, branches into multiple flow paths via the gas header 22, and flows into the outdoor heat exchanger 200. The gas refrigerant that flows into the outdoor heat exchanger 200 exchanges heat with outside air supplied by the blower fan 23, condenses, and becomes liquid refrigerant. The liquid refrigerant passes through the liquid-side distribution pipe 28 and merges into one flow path by the distributor 24, then passes through the expansion valve 25 and the liquid check valve 26, is transported through the refrigerant pipe 4L, and flows into the indoor unit 3.

[0030] The liquid refrigerant is decompressed in the expansion valve 31 of the indoor unit 3 to become a low-temperature, low-pressure two-phase gas-liquid refrigerant. The refrigerant is then distributed to multiple flow paths by the distributor 32 and the liquid-side distribution pipe 35 and flows into the indoor heat exchanger 300, where it exchanges heat with indoor air supplied by the blower fan 34. When the refrigerant exchanges heat in the indoor heat exchanger 300, it evaporates to become a gas refrigerant, and the air supplied by the blower fan 34 is cooled by the latent heat of evaporation of the refrigerant and is blown into the room as cool air.

[0031] The heat-exchanged gas refrigerant has its flow paths joined by the gas header 33, then transported through the gas refrigerant pipe 4G, passes through the gas check valve 29 of the outdoor unit 2 to adjust for excess liquid return that may temporarily occur in the tank (accumulator) 27, and then flows into the compressor 21. By repeating these steps, a refrigeration cycle is formed, and the air conditioner 1 performs cooling operation, enabling the room to be at a desired temperature.

[0032] When the air conditioner 1 is in heating operation, the connection between the inflow and outflow of the refrigerant of the four-way valve 20 is as shown by the dashed lines. The dashed arrows in Fig. 2 indicate the direction in which the refrigerant flows during heating operation.

[0033] Next, the general relationship between the amount of refrigerant and the efficiency of the air conditioner 1 will be described with reference to Fig. 3. Fig. 3 is a diagram illustrating the relationship between the total amount of refrigerant charged in the refrigeration cycle and the coefficient of performance (COP) of the air conditioner 1. Note that the graph in Fig. 3 is an example showing the general relationship between the amount of refrigerant and the COP, and is not intended to limit the embodiments.

[0034] The horizontal axis of Fig. 3 represents the total amount of refrigerant sealed in the refrigeration cycle of the air conditioner 1, and the vertical axis represents the coefficient of performance of the refrigeration cycle. In Fig. 3, curve A represents the coefficient of performance during cooling operation, curve B represents the coefficient of performance during heating operation, and curve C represents the average coefficient of performance during cooling operation and heating operation.

[0035] As shown in FIG. 3, the amount of refrigerant at which the coefficient of performance peaks in cooling operation is generally greater than the amount of refrigerant at which the performance peaks in heating operation.

[0036] Generally, cooling operation has a greater impact on the performance of the air conditioner 1 than heating operation, so the amount of refrigerant is sometimes determined based on the peak performance during cooling operation. In this case, the amount of refrigerant during heating operation is excessive, resulting in a decrease in performance during heating operation. For this reason, it is preferable to adjust the amount of refrigerant passing through the heat exchanger by, for example, providing a receiver tank so as to reduce the amount of refrigerant contributing to air conditioning during heating operation. However, providing a receiver tank increases costs and increases the size of the device. Therefore, in this embodiment, a sub-cooler is provided in the heat exchanger to reduce the amount of excess refrigerant during heating operation and improve performance during cooling operation.

[0037] Fig. 4 is a diagram showing the configuration of an outdoor heat exchanger 200 including a subcooler 201 in this embodiment. The outdoor heat exchanger 200 shown in Fig. 4 is composed of three rows of heat transfer tubes, which will be referred to below for convenience as the "first row (C1)," "second row (C2)," and "third row (C3)" from the front side to the back side in the y-axis direction.

[0038] In Figure 4, the solid arrows indicate the direction in which the refrigerant flows when the air conditioning device 1 is operating in cooling mode, and the dashed arrows indicate the direction in which the refrigerant flows when the air conditioning device 1 is operating in heating mode.

[0039] In addition, elements indicated by circles in Fig. 4 represent heat transfer tubes, and multiple heat transfer tubes are connected with joints such as U-shaped tubes. In Fig. 4, the lines connecting multiple heat transfer tubes represent joints. Joints indicated by solid lines are provided on the front side in the x-axis direction, and joints indicated by dashed lines are provided on the back side in the x-axis direction.

[0040] In the outdoor heat exchanger 200 of the present embodiment shown in Fig. 4, a part of the heat transfer tube is configured as a subcooler 201. The area surrounded by a dashed line in Fig. 4 is configured as the subcooler 201. The subcooler 201 is provided downstream of the distributor 24 in the direction in which the refrigerant flows in the refrigeration cycle.

[0041] Now, consider the case where the air conditioner 1 is operating in cooling mode. When the air conditioner 1 is operating in cooling mode, gas refrigerant flows into the first row of heat transfer tubes, exchanges heat by traveling back and forth through multiple heat transfer tubes, and then flows into the third row of heat transfer tubes. In this process, the gas refrigerant changes to liquid refrigerant. The liquid refrigerant that flows out of the third row flows into the distributor 24. That is, in FIG. 4, there are five refrigerant flow paths indicated by L1 to L5, and the liquid refrigerant that has passed through each path merges in the distributor 24. Note that flow paths L4 and L5 are omitted from FIG. 4.

[0042] The liquid refrigerant merges in the distributor 24 and then flows into the subcooler 201. In the subcooler 201, the liquid refrigerant first passes through a branch pipe and is split into two flow paths. The liquid refrigerant from each flow path then passes through the first row of heat transfer tubes and merges at the second row of T-shaped joints. After the flow paths merge, the refrigerant passes through the third row of heat transfer tubes and flows into the expansion valve 25.

[0043] In the subcooler 201 of this embodiment, the flow paths are joined at the distributor 24 and then split into two again at a branch pipe, thereby improving the refrigerant distribution. Furthermore, the outdoor heat exchanger 200 in FIG. 4 has five refrigerant flow paths in locations other than the subcooler 201, but by joining the flow paths at the distributor 24, the flow velocity of the refrigerant can be improved (in other words, if each of the five flow paths were to form a subcooler, the flow velocity of the refrigerant would be slower and the heat transfer coefficient would be lower).

[0044] Furthermore, conventional subcoolers are configured using only the first row of heat transfer tubes in a heat exchanger in order to reduce pressure loss. However, the subcooler 201 of this embodiment is configured using multiple rows (i.e., the first to third rows) of heat transfer tubes, which enables the flow rate to be increased even when the refrigerant circulation volume is small, such as during cooling operation under intermediate conditions where the output is about 50% of the rated output, thereby improving heat exchange performance and the performance of the air conditioner 1.

[0045] 4, the subcooler 201 of this embodiment is provided below the outdoor heat exchanger 200, that is, at a position away from the blower fan 23 and where the amount of heat transfer required for heat exchange is small. Since the outdoor unit 2 of the embodiment to be described is configured as a top-flow (upward-blowing) outdoor unit 2, the blower fan 23 is provided above the outdoor heat exchanger 200, and the portion configured as the subcooler 201 is located below the outdoor heat exchanger 200 and away from the blower fan. For example, the heat transfer tubes that form each of the flow paths L1 to L5 in FIG. 4 are located near the blower fan 23, at a position where the main heat exchange takes place. On the other hand, the heat transfer tubes that form the subcooler 201 are located farther from the blower fan 23 than the heat transfer tubes that form each of the flow paths L1 to L5. In this way, by providing the subcooler 201 in a position where the contribution of heat exchange by the heat transfer tubes is small, excess refrigerant when the air conditioner 1 is in heating operation passes through the subcooler 201, where a small amount of heat exchange occurs, and the refrigerant is less likely to gasify. Therefore, when the air conditioner 1 is in heating operation, the subcooler 201 can be configured as a means for storing refrigerant. In this way, even when the amount of refrigerant charged is large (for example, when the amount of refrigerant charged is equal to the peak performance during cooling operation), the performance during heating operation can be improved by storing the excess refrigerant in the subcooler 201.

[0046] In this embodiment, as shown in Fig. 4, the subcooler 201 is configured to include multiple rows of heat transfer tubes, allowing for an increased amount of refrigerant to be stored. Furthermore, by using second and third rows of heat transfer tubes, the subcooler can flow a two-phase refrigerant that maintains a low dryness and high density state because the liquid refrigerant before expansion and the air-side heat transfer are low even after expansion, preventing evaporation due to a slow air velocity and low heat transfer on the air side. This suppresses subcooling in the condenser, thereby suppressing pressure increases. This improves the efficiency of the compressor and the performance of the air conditioner 1.

[0047] Generally, if refrigerant accumulates on the condenser side and the degree of subcooling increases, the heat transfer area that effectively functions as a condenser decreases, resulting in a high refrigerant pressure. Therefore, by preventing liquid refrigerant from accumulating in the condenser, excessive subcooling is prevented, and pressure increases can be suppressed. Here, if the density of the refrigerant contained in the parts of the refrigeration cycle other than the condenser increases, the amount of refrigerant in those parts increases, and the amount of refrigerant contained in the condenser decreases. In other words, the degree of subcooling in the condenser decreases, and pressure increases can be suppressed. Therefore, in this embodiment, by configuring the subcooler 201 using multiple rows of heat transfer tubes, the density of the refrigerant in the outdoor heat exchanger during heating operation can be increased (i.e., the amount of refrigerant held in the evaporator can be increased). This reduces the amount of refrigerant held in the condenser, suppressing pressure increases, improving compressor efficiency, and improving the performance of the air conditioner 1.

[0048] The outdoor heat exchanger 200 of this embodiment may be configured to include a plurality of refrigerant flow paths configured as sub-coolers 201, as shown in Fig. 5. Fig. 5 is a diagram showing the configuration of the outdoor heat exchanger 200 of this embodiment that includes a plurality of refrigerant flow paths configured as sub-coolers 201. The outdoor heat exchanger 200 shown in Fig. 5 is configured by combining two outdoor heat exchangers 200 of Fig. 4 so that they are symmetrical on the left and right.

[0049] The area surrounded by a dashed line in Fig. 5 is the sub-cooler 201 of this embodiment. As shown in Fig. 5, two distributors 24a, 24b are provided in the outdoor heat exchanger 200. Branch pipes are provided at the ends where the flow paths of the distributors 24a, 24b join, and the flow paths of the refrigerant during cooling operation are branched by the branch pipes (in other words, the flow paths of the refrigerant during heating operation are joined by the branch pipes).

[0050] During cooling operation, the refrigerant flowing through the multiple flow paths of the subcooler 201 passes through the heat transfer tubes of the heat exchanger, and then the flow paths merge at a joint 103' configured to allow the flow paths to merge (or branch), and then flow into one expansion valve 25. The refrigerant that has passed through the expansion valve 25 has its flow paths branched at a joint 103'' configured to allow the flow paths to branch (or merge), passes through the heat transfer tubes, and then flows into the indoor unit 3 through the refrigerant pipe 4L.

[0051] As shown in Fig. 5, by providing multiple refrigerant flow paths in one sub-cooler 201, the amount of refrigerant passing through the sub-cooler 201 can be increased, thereby enabling efficient heat transfer. Furthermore, since the sub-cooler 201 shown in Fig. 5 has multiple refrigerant flow paths, the amount of refrigerant that can be stored during heating operation can be increased.

[0052] As described above, in this embodiment, by configuring a part of the heat exchanger as the subcooler 201, and in particular by using a multi-stage subcooler pass structure formed by multiple rows of heat transfer tubes, it is possible to improve performance both during cooling operation and heating operation.

[0053] According to the embodiments of the present invention described above, it is possible to provide an air conditioner that improves the heat exchange performance of the heat exchanger during cooling operation and heating operation.

[0054] Although the present invention has been described above with reference to embodiments, the present invention is not limited to the above-described embodiments, and any embodiment that can be conceived by a person skilled in the art is included in the scope of the present invention as long as it exhibits the functions and effects of the present invention. [Explanation of symbols]

[0055] 1...Air conditioning equipment, 2...Outdoor unit, 3...Indoor unit, 4...refrigerant piping, 20...Four-way valve, 21...Compressor, 22...Gas header, 23...Ventilation fan, 24...Distributor, 25...Expansion valve, 26...Liquid check valve, 28...Liquid side distribution piping, 29...Gas check valve, 31...expansion valve, 32...Distributor, 33...Gas header, 34...blower fan, 35...Liquid side distribution piping, 100...heat exchanger, 101...heat transfer tube, 102... Finn, 103...Joint, 200...Outdoor heat exchanger, 201...Subcooler, 300…Indoor heat exchanger

Claims

1. a heat exchanger having a plurality of rows each composed of a plurality of heat transfer tubes, and exchanging heat by passing a refrigerant through a plurality of refrigerant flow paths each formed by connecting the heat transfer tubes; a pipe that joins the plurality of refrigerant flow paths when the heat exchanger functions as a condenser; a subcooler having a refrigerant flow path formed by connecting a plurality of rows of heat transfer tubes constituting the heat exchanger; Including, the subcooler is provided downstream of the piping in a direction in which the refrigerant flows when the heat exchanger functions as a condenser. Air conditioning equipment.

2. The subcooler is a first joint that branches the refrigerant flowing out of the piping when the heat exchanger functions as a condenser; a first refrigerant flow path and a second refrigerant flow path branched by the first joint; a second joint that joins the first refrigerant flow path and the second refrigerant flow path; having The air conditioning apparatus according to claim 1.

3. Further comprising a blower fan disposed above the heat exchanger. The air conditioning apparatus according to claim 1.

4. The subcooler is configured to include the lowest heat transfer tube of the heat exchanger. The air conditioning apparatus according to claim 3.

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