JP5704898B2 - Heat exchanger and air conditioner equipped with the heat exchanger - Google Patents

Description

  The present invention relates to a heat exchanger and an air conditioner including the heat exchanger.

  Conventionally, in order to increase the degree of supercooling of the liquid refrigerant that has flowed out of the outdoor heat exchanger during the cooling operation, an air conditioner including a double-tube heat exchanger has been proposed. As a double pipe heat exchanger used in such a conventional air conditioner, for example, “one double pipe 41 is formed of a straight portion 45 and a bent portion 48, and the straight portions 45 and the bent portion 48 are formed. It has been proposed to “wrap around one another” (see, for example, Patent Document 1).

Japanese Patent Laying-Open No. 2005-345074 (Summary, FIG. 4)

  A conventional double tube heat exchanger generally has a multi-winding double tube heat exchanger structure in which a double tube is spirally wound in order to increase the volume of a portion for heat exchange ( For example, see Patent Document 1). And such a conventional double pipe heat exchanger was provided separately from the outdoor heat exchanger. For this reason, the conventional air conditioning apparatus has a problem that a sufficient installation space is required to install the double-pipe heat exchanger, and the space efficiency is poor. In addition, the piping configuration becomes complicated, and the cost of the air conditioner increases.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a heat exchanger incorporating a double-pipe heat exchanger and an air conditioner equipped with the heat exchanger. .

The heat exchanger according to the present invention includes a plurality of paths through which the refrigerant flows, a first distribution header connected to one end of the plurality of paths, and a second distribution connected to the other end of the plurality of paths. The second distribution header is connected to the first piping connected to the other end of the plurality of paths, the branch piping for branching a part of the refrigerant flowing through the first piping, and the branch piping. A second pipe that exchanges heat between the refrigerant flowing in from the branch pipe and the refrigerant flowing in the first pipe, and a first expansion device that is provided in the branch pipe and expands the refrigerant flowing into the second pipe , The first pipe and the second pipe are arranged along the vertical direction, and the first pipe extends from the lower part to the upper part of the first pipe when the refrigerant is distributed from the first pipe to the plurality of paths. The refrigerant flows, and the cross-sectional area of the flow path of the first pipe is 1 along the flow direction of the refrigerant flowing from the bottom of the pipe to the upper one in which are larger.
The heat exchanger according to the present invention includes a plurality of paths through which the refrigerant flows, a first distribution header connected to one end of the plurality of paths, and a first connection connected to the other end of the plurality of paths. A second distribution header, wherein the second distribution header includes a first pipe connected to the other end of the plurality of paths, a branch pipe that branches a part of the refrigerant flowing through the first pipe, and a branch pipe. A second pipe that is connected and exchanges heat between the refrigerant flowing in from the branch pipe and the refrigerant flowing in the first pipe; and a first expansion device that is provided in the branch pipe and expands the refrigerant flowing into the second pipe. The first pipe and the second pipe are arranged along the up-down direction, and the first pipe is located above the first pipe in the state in which the refrigerant is distributed from the first pipe to the plurality of paths. The refrigerant flows through the first pipe, and the cross-sectional area of the flow path of the first pipe is Since the cross-sectional area of the flow path of the two pipes decreases along the flow direction of the refrigerant flowing from the lower part to the upper part of the first pipe, it increases along the flow direction of the refrigerant flowing from the lower part to the upper part of the first pipe. It is what.

  An air conditioner according to the present invention is an air conditioner including a compressor, a flow path switching device, an outdoor heat exchanger, a second expansion device, and an indoor heat exchanger, and the heat exchanger is an outdoor heat exchanger. It was used as.

  In the present invention, the second distribution header constituting the heat exchanger is a double pipe heat exchanger. That is, the heat exchanger of the present invention has a double pipe heat exchanger built in the second distribution header. For this reason, the installation space for the double-tube heat exchanger, which was conventionally necessary, is no longer necessary, and the space efficiency of the air conditioner can be improved. Moreover, since it can prevent that piping structure becomes complicated, the increase in the cost of an air conditioning apparatus can be suppressed.

It is a system configuration figure showing the air harmony device concerning Embodiment 1 of the present invention. It is a longitudinal cross-sectional schematic diagram which shows the 2nd distribution header vicinity of the outdoor heat exchanger which concerns on Embodiment 1 of this invention. It is ZZ sectional drawing of FIG. It is a longitudinal cross-sectional schematic diagram which shows another example of the 2nd distribution header which concerns on Embodiment 1 of this invention. It is a longitudinal cross-sectional schematic diagram which shows another example of the 2nd distribution header which concerns on Embodiment 1 of this invention. It is a plane cross-sectional schematic diagram which shows another example of the 2nd distribution header which concerns on Embodiment 1 of this invention. It is a plane cross-sectional schematic diagram which shows another example of the 2nd distribution header which concerns on Embodiment 1 of this invention. It is a plane cross-sectional schematic diagram which shows another example of the 2nd distribution header which concerns on Embodiment 1 of this invention. It is a system block diagram which shows the air conditioning apparatus which concerns on Embodiment 2 of this invention. It is a side view which shows the outdoor heat exchanger of the air conditioning apparatus which concerns on Embodiment 2 of this invention. It is a system block diagram which shows another example of the air conditioning apparatus which concerns on Embodiment 2 of this invention. It is a longitudinal cross-sectional schematic diagram which shows an example of the 2nd distribution header of the air conditioning apparatus which concerns on Embodiment 3 of this invention. It is a longitudinal cross-sectional schematic diagram which shows another example of the 2nd distribution header of the air conditioning apparatus which concerns on Embodiment 3 of this invention. It is a longitudinal cross-sectional schematic diagram which shows another example of the 2nd distribution header of the air conditioning apparatus which concerns on Embodiment 3 of this invention. It is a longitudinal cross-sectional schematic diagram which shows another example of the 2nd distribution header of the air conditioning apparatus which concerns on Embodiment 3 of this invention. It is a system block diagram which shows the conventional air conditioning apparatus provided with the double tube heat exchanger.

Embodiment 1 FIG.
Hereinafter, with reference to drawings, the heat exchanger concerning Embodiment 1 of the present invention and the air harmony device provided with this heat exchanger are explained. In the drawings describing the following embodiments, the size and shape of each component may be different from actual ones.

FIG. 1 is a system configuration diagram showing an air-conditioning apparatus according to Embodiment 1 of the present invention.
The air conditioner 50 according to Embodiment 1 includes a heat pump type refrigeration cycle circuit that circulates a refrigerant. The refrigeration cycle circuit includes a compressor 1, a four-way valve 3, an outdoor heat exchanger 4, an expansion device 25 such as an expansion valve, an indoor heat exchanger 26, and the like. The compressor 1 compresses and discharges the sucked refrigerant. The four-way valve 3 switches the flow path of the refrigerant discharged from the compressor 1 during the cooling operation and the heating operation. In other words, the four-way valve 3 uses a flow path of the refrigerant discharged from the compressor 1 as a flow path that flows into the outdoor heat exchanger 4 (during cooling operation) or a flow path that flows into the indoor heat exchanger 26 (during heating operation). ).

  The outdoor heat exchanger 4 exchanges heat between the refrigerant flowing through the outdoor heat exchanger 4 and outdoor air. The outdoor heat exchanger 4 has a plurality of paths through which the refrigerant flows. The plurality of paths are, for example, heat transfer tubes of a fin tube type heat exchanger. A first distribution header 5 and a second distribution header 10 are connected to the plurality of paths. The first distribution header 5 distributes the gas refrigerant to a plurality of paths when the outdoor heat exchanger 4 functions as a condenser (at the time of cooling operation). Moreover, the 1st distribution header 5 joins the gas refrigerant | coolant which flowed out from the some path | pass when the outdoor heat exchanger 4 functions as an evaporator (at the time of heating operation). When the outdoor heat exchanger 4 functions as a condenser (during cooling operation), the second distribution header 10 joins the liquid refrigerant that has flowed out from a plurality of paths. The second distribution header 10 distributes the gas-liquid two-phase refrigerant to a plurality of paths when the outdoor heat exchanger 4 functions as an evaporator (at the time of heating operation).

  The expansion device 25 expands (depressurizes) the refrigerant flowing from the outdoor heat exchanger 4 or the indoor heat exchanger 26. The indoor heat exchanger 26 exchanges heat between the refrigerant flowing through the indoor heat exchanger 26 and room air. The four-way valve 3 corresponds to the flow path switching device in the present invention, and the expansion device 25 corresponds to the second expansion device of the present invention.

  Moreover, the air conditioning apparatus 50 according to Embodiment 1 of the present invention includes the oil separator 2 and the accumulator 9. The oil separator 2 is provided on the discharge side of the compressor 1 and separates and extracts the hydraulic oil mixed in the discharge refrigerant. The accumulator 9 is provided between the four-way valve 3 and the compressor 1 and separates the liquid refrigerant and the gas refrigerant. Since the compressor 1 sucks the gas refrigerant separated by the accumulator 9, the liquid back to the compressor 1 can be prevented.

  Here, in order to compare the air conditioner 50 according to the first embodiment with the conventional air conditioner provided with the double pipe heat exchanger, the conventional air conditioner provided with the double pipe heat exchanger. explain.

FIG. 16: is a system block diagram which shows the conventional air conditioning apparatus provided with the double tube heat exchanger. In addition, in the following figures including FIG. 16, illustration of the expansion device 25 and the indoor heat exchanger 26 may be omitted.
In the conventional air conditioner 100, the second distribution header 6 of the outdoor heat exchanger 4 has only a function of joining and branching the refrigerant. Therefore, the double pipe heat exchanger 110 that increases the degree of supercooling of the liquid refrigerant flowing out of the outdoor heat exchanger 4 includes the outdoor heat exchanger 4 (more specifically, the second distribution header 6), the expansion device 25, and the like. Is provided in the liquid side pipe 27 for connecting the two. The double pipe heat exchanger 110 has two flow paths formed therein, and the refrigerant flowing through the liquid side pipe 27 passes through one of the flow paths. Further, a branch pipe 108 a branched from the liquid side pipe 27 is connected to the other flow path. That is, the refrigerant expanded by the expansion device 107 flows through the other flow path when passing through the branch pipe 108a. For example, during cooling operation, the degree of supercooling of the liquid refrigerant flowing out of the outdoor heat exchanger 4 is increased by exchanging heat between the refrigerant flowing in one channel and the refrigerant flowing in the other channel in the double pipe heat exchanger 110. (That is, the cooling performance can be improved). The refrigerant that has passed through the other flow path of the double-pipe heat exchanger 110 flows into the upstream side of the accumulator 9 through the pipe 108b.

  However, the conventional air conditioner 100 requires a sufficient space for providing the double pipe heat exchanger 110, and the air conditioner 100 becomes large. In addition, the conventional air conditioner 100 has a complicated piping configuration and increases manufacturing costs.

  Therefore, the air conditioner 50 according to Embodiment 1 improves the refrigeration performance and prevents the air conditioner 100 from increasing in size, manufacturing costs, and the like, so that the double-tube heat exchanger is used for outdoor heat exchange. Built in the container 4. Specifically, in the air conditioner 50 according to Embodiment 1, the outdoor heat exchanger 4 is configured as follows.

FIG. 2 is a schematic longitudinal sectional view showing the vicinity of the second distribution header of the outdoor heat exchanger according to Embodiment 1 of the present invention. FIG. 3 is a ZZ cross-sectional view of FIG. Hereinafter, the details of the outdoor heat exchanger 4 according to Embodiment 1 will be described with reference to FIGS. 2, 3, and 1.
The second distribution header 10 of the outdoor heat exchanger 4 according to Embodiment 1 includes, for example, a hollow cylindrical outer tube 18, for example, a hollow cylindrical inner tube 19, a branch connecting the outer tube 18 and the inner tube 19. A pipe 8a and a throttle device 7 such as an expansion valve are provided. Here, the outer tube 18 corresponds to the first piping of the present invention, the inner tube 19 corresponds to the second piping of the present invention, and the expansion device 7 corresponds to the first expansion device of the present invention.

  The outer tube 18 is disposed, for example, in the vertical direction, and is connected to a plurality of paths via the distribution lead pipe 20. The outer pipe 18 distributes the gas refrigerant to a plurality of paths when the outdoor heat exchanger 4 functions as a condenser (at the time of cooling operation). The outer pipe 18 joins the gas refrigerant flowing out from the plurality of paths when the outdoor heat exchanger 4 functions as an evaporator (at the time of heating operation). Inside the outer tube 18, an inner tube 19 having a diameter smaller than that of the outer tube 18 is arranged. The outer pipe 18 and the inner pipe 19 are connected to each other in the vicinity of their lower ends by a branch pipe 8a. The upper end portion of the inner pipe 19 is connected to the upstream side of the accumulator 9 through the pipe 8b. If the accumulator 9 is not provided in the refrigeration cycle circuit, the pipe 8b may be connected to the suction side of the compressor 1.

(Operation)
The air conditioner 50 provided with the outdoor heat exchanger 4 according to the first embodiment operates as follows.

First, the operation of the air conditioner 50 during the cooling operation will be described.
During the cooling operation, the high-pressure gas refrigerant discharged from the compressor 1 flows into the outdoor heat exchanger 4 through the four-way valve 3 after the hydraulic oil is separated by the oil separator 2. The high-pressure gas refrigerant flowing into the outdoor heat exchanger 4 is distributed by the first distribution header 5 and flows into each path. The high-pressure gas refrigerant flowing into each path is condensed by exchanging heat with outdoor air and becomes high-pressure liquid refrigerant. The high-pressure liquid refrigerant flows into the outer pipe 18 through the distribution lead pipe 20 and joins. The high-pressure liquid refrigerant merged in the outer tube 18 is cooled by the low-temperature refrigerant flowing in the inner tube 19 while flowing between the inner peripheral surface of the outer tube 18 and the outer peripheral surface of the inner tube 19, and the degree of supercooling increases. (Supercooling is promoted).

  A part of the liquid refrigerant whose degree of supercooling has increased passes through the liquid side pipe 27 and flows into the expansion device 25. On the other hand, the remaining part of the liquid refrigerant whose degree of supercooling has increased flows into the branch pipe 8a and is decompressed by the expansion device 7 to become a low-temperature gas-liquid two-phase refrigerant. The refrigerant flows into the inner pipe 19, cools the refrigerant flowing between the inner peripheral surface of the outer pipe 18 and the outer peripheral surface of the inner pipe 19, and then flows into the accumulator 9 through the pipe 8 b. In the first embodiment, the refrigerant flowing through the outer tube 18 (more specifically, the refrigerant flowing between the inner peripheral surface of the outer tube 18 and the outer peripheral surface of the inner tube 19) and the flow of the refrigerant flowing through the inner tube 19 The direction is counterflow. By making the flow direction of the refrigerant flowing through both pipes counter flow, heat exchange of the refrigerant flowing through both pipes can be promoted.

  When attention is paid again to the low-temperature liquid refrigerant flowing into the expansion device 25, the liquid refrigerant is decompressed by the expansion device 25 to become a gas-liquid two-phase refrigerant and flows into the indoor heat exchanger 26. The low-temperature and low-pressure gas-liquid two-phase refrigerant that has flowed into the indoor heat exchanger 26 evaporates while cooling the indoor air, and flows into the accumulator 9 through the four-way valve 3. The refrigerant flowing into the accumulator 9 is separated into a liquid refrigerant and a gas refrigerant. The gas refrigerant separated by the accumulator 9 is sucked into the compressor 1 and compressed again.

Next, operation | movement of the air conditioning apparatus 50 at the time of heating operation is demonstrated.
During the heating operation, the high-pressure gas refrigerant discharged from the compressor 1 flows into the indoor heat exchanger 26 through the four-way valve 3 after the hydraulic oil is separated by the oil separator 2. The high-pressure gas refrigerant that has flowed into the indoor heat exchanger 26 condenses while heating the indoor air, and becomes liquid refrigerant and flows into the expansion device 25. The liquid refrigerant flowing into the expansion device 25 is reduced in pressure to become a gas-liquid two-phase refrigerant, and then flows into the outdoor heat exchanger 4 through the liquid side pipe 27.

  The gas-liquid two-phase refrigerant that has flowed into the outdoor heat exchanger 4 is distributed by the second distribution header 10 and flows into each path. The gas-liquid two-phase refrigerant that has flowed into each path evaporates by exchanging heat with outdoor air, and becomes, for example, a low-pressure gas refrigerant. This refrigerant joins at the first distribution header 5 and flows into the accumulator 9 through the four-way valve 3. The refrigerant flowing into the accumulator 9 is separated into a liquid refrigerant and a gas refrigerant. The gas refrigerant separated by the accumulator 9 is sucked into the compressor 1 and compressed again.

  During the heating operation, the expansion device 7 may be closed so that the gas-liquid two-phase refrigerant flows only through the outer pipe 18 of the second distribution header 10, or both the outer pipe 18 and the inner pipe 19 may be closed. The opening degree of the expansion device 7 may be adjusted so that the gas-liquid two-phase refrigerant flows. By circulating the refrigerant also in the inner pipe 19, it is possible to reduce the circulation amount of the gas-liquid two-phase refrigerant that passes through the outer pipe 18 and flows into each path. Thereby, the pressure loss in the outer tube 18 and each path can be reduced. In addition, since the gas-liquid two-phase refrigerant passing through the inner pipe 19 and the gas-liquid two-phase refrigerant passing through the outer pipe 18 exchange heat, the enthalpy of the gas-liquid two-phase refrigerant flowing into each path can be reduced. The evaporation capacity of the outdoor heat exchanger 4 can be increased.

  As described above, in the outdoor heat exchanger 4 configured as in the first embodiment and the air conditioner 50 including the outdoor heat exchanger 4, the double pipe heat exchanger is replaced with the second heat exchanger 4 of the outdoor heat exchanger 4. Since it is built in the distribution header 10, the space efficiency of the air conditioner 50 can be improved while sufficiently ensuring the degree of supercooling during the cooling operation. Moreover, since a piping structure can be simplified, the increase in the cost of the air conditioning apparatus 50 can be suppressed.

  In addition, the structure of the outdoor heat exchanger 4 shown in this Embodiment 1 (FIGS. 1-3) is an example to the last, and can be set as various structures, as long as it has the effect of this invention.

  For example, during cooling operation, when the refrigerant is caused to flow into the inner pipe 19 from the vicinity of the lower end portion of the inner pipe 19, the refrigerant may stagnate in the lower part of the outdoor heat exchanger 4 (for example, in a path disposed at the lower part). is there. The refrigerant with the highest degree of supercooling in the outer pipe 18 (the refrigerant near the lower portion of the outer pipe 18, in other words, the refrigerant near the outlet of the outer pipe 18) has the lowest enthalpy among the refrigerant flowing through the inner pipe 19. This is because heat is exchanged with things. If the refrigerant lies in the lower part of the outdoor heat exchanger 4, efficient heat exchange cannot be performed in a part of the outdoor heat exchanger 4, and the condensation capacity of the outdoor heat exchanger 4 is reduced.

  In such a case, the second distribution header 10 of the outdoor heat exchanger 4 may be configured as follows, for example, so that the refrigerant subcooling balance in the vicinity of the outlet of each pass is made uniform.

FIG. 4 is a schematic longitudinal sectional view showing another example of the second distribution header according to Embodiment 1 of the present invention.
For example, as shown in FIG. 4, a branch pipe 8 a may be connected to a substantially central part (a position not near the lower part) of the inner pipe 19. By configuring the second distribution header 10 in this way, heat exchange with the refrigerant having the largest degree of supercooling in the outer pipe 18 (refrigerant near the lower portion of the outer pipe 18, in other words, refrigerant near the outlet of the outer pipe 18). The refrigerant in the inner pipe 19 is in a state with a high enthalpy. Thereby, the supercooling degree balance of the refrigerant | coolant in the exit vicinity of each path | pass can be equalize | homogenized, and it can suppress that a refrigerant | coolant sleeps in the lower part of the outdoor heat exchanger 4. FIG.

FIG. 5 is a schematic longitudinal sectional view showing still another example of the second distribution header according to Embodiment 1 of the present invention.
For example, the second distribution header 10 shown in FIG. 5 is provided with a plurality of branch bypass pipes 29 at the end of the branch pipe 8a. These branch bypass pipes 29 are connected to the inner pipe 19 along the refrigerant flow direction in the inner pipe 19 (longitudinal direction of the inner pipe 19). That is, the branch pipe 8 a is branched into a plurality of flow paths and connected to the inner pipe 19. By configuring the second distribution header 10 in this way, the refrigerant having substantially the same enthalpy flows into the inner pipe 19, and the refrigerant flowing out from each path exchanges heat with the refrigerant having substantially the same enthalpy. It will be. Thereby, the supercooling degree balance of the refrigerant | coolant in the exit vicinity of each path | pass can be equalize | homogenized, and it can suppress that a refrigerant | coolant sleeps in the lower part of the outdoor heat exchanger 4. FIG.

  Further, for example, the configuration of the second distribution header 10 (first piping and second piping) having a double tube heat exchanger structure is also limited to the configuration of the outer tube 18 and the inner tube 19 shown in FIGS. It is not something.

6 to 8 are schematic cross-sectional views showing another example of the second distribution header according to Embodiment 1 of the present invention. These drawings show a cross-section at the same position as FIG.
For example, as shown in FIG. 6, one pipe is divided by a partition plate, and the first pipe 24 (corresponding to the outer pipe 18 in FIG. 3) and the second pipe 23 (corresponding to the inner pipe 19 in FIG. 3) are integrated. It may be formed.
Further, for example, as shown in FIG. 7, the outer peripheral surface of the first pipe 24 (corresponding to the outer tube 18 in FIG. 3) and the outer peripheral surface of the second pipe 23 (corresponding to the inner tube 19 in FIG. 3) are in contact with each other. The second distribution header 10 may be configured.
Further, for example, as shown in FIG. 8, the inner peripheral surface of the first pipe 24 (corresponding to the outer tube 18 in FIG. 3) and the outer peripheral surface of the second pipe 23 (corresponding to the inner tube 19 in FIG. 3) are in contact. The second distribution header 10 may be configured.
In the second distribution header 10 shown in FIGS. 6 to 8, the refrigerant flowing out from each path flows through the first pipe 24 during the cooling operation. Further, the refrigerant that has been decompressed by the expansion device 7 through the branch pipe 8 a flows through the second pipe 23.

  Here, in the case of the 2nd distribution header 10 shown in FIGS. 6-8, it is good to make the cross-sectional area of the 2nd piping 23 smaller than the cross-sectional area of the 1st piping 24. FIG. This is because the flow rate of the refrigerant flowing through the second pipe 23 can be controlled by the expansion device 7 and the flow rate of the refrigerant flowing through the second pipe 23 is sufficiently smaller than the flow rate of the refrigerant flowing through the first pipe 24. Moreover, it is for preventing the pressure loss of the 1st piping 24 becoming excessive when circulating a refrigerant | coolant only to the 1st piping 24 at the time of heating operation.

Embodiment 2. FIG.
In preparation for the case where the refrigerant has fallen into the outdoor heat exchanger 4 during the cooling operation, for example, the air conditioner 50 may be provided with a stagnation correction device such as the following. In the second embodiment, items that are not particularly described are the same as those in the first embodiment, and the same functions and configurations are described using the same reference numerals.

FIG. 9 is a system configuration diagram showing an air-conditioning apparatus according to Embodiment 2 of the present invention. FIG. 10 is a side view showing an outdoor heat exchanger of the air conditioner.
The air conditioner 50 according to the second embodiment is provided with a stagnation correction device that corrects the stagnation of the refrigerant in the outdoor heat exchanger 4 in the air conditioner 50 shown in the first embodiment. This stagnation correcting apparatus includes a bypass pipe 13, an opening / closing device 14 that is a solenoid valve, and a throttling device 15 that is a capillary, for example. Here, the diaphragm device 15 corresponds to a third diaphragm device of the present invention.

  One end of the bypass pipe 13 is connected to the discharge side of the compressor 1, and the other end passes through the outdoor heat exchanger 4 and the other end is the suction side of the compressor 1 (in the case of the second embodiment, the upstream side of the accumulator 9). It is connected to the. The high-pressure bypass pipe inlet 22 where the refrigerant flowing through the bypass pipe 13 (refrigerant discharged from the compressor 1) flows into the outdoor heat exchanger 4 is in the vicinity of the lower pass outlet 21 having the highest degree of supercooling. Is provided. The opening / closing device 14 opens and closes the flow path of the bypass pipe 13, and is provided in the bypass pipe 13 (pipe shown as the bypass pipe 13a in FIG. 9) between the discharge side of the compressor 1 and the outdoor heat exchanger 4. It has been. The expansion device 15 depressurizes the refrigerant flowing through the bypass pipe 13, and is provided in the bypass pipe 13 (pipe shown as the bypass pipe 13b in FIG. 9) between the outdoor heat exchanger 4 and the suction side of the compressor 1. It has been.

  The outdoor heat exchanger 4 of the air-conditioning apparatus 50 according to Embodiment 2 is provided with a thermistor 12 that detects the stagnation of the refrigerant. The thermistor 12 is provided, for example, at the exit of the lower path where the refrigerant is likely to sleep.

  When the refrigerant stagnation is detected based on the temperature detected by the thermistor 12, the opening / closing device 14 is opened, and the high-pressure gas refrigerant discharged from the compressor 1 is caused to flow to the bypass pipe 13. The high-pressure gas refrigerant flows through the bypass pipe 13 disposed in the outdoor heat exchanger 4, whereby the refrigerant that has stagnated in the outdoor heat exchanger 4 can be evaporated. At this time, the refrigerant flowing through the bypass pipe 13 b that has been cooled and liquefied by flowing through the bypass pipe 13 disposed in the outdoor heat exchanger 4 is decompressed (expanded) by the expansion device 15, and therefore is supplied to the compressor 1. The liquid back can be prevented.

  In addition, the stagnation correction apparatus which correct | amends that a refrigerant | coolant stagnates in the inside of the outdoor heat exchanger 4 is not limited to what is shown in FIG. 9, For example, you may make the following structures.

FIG. 11 is a system configuration diagram showing another example of the air-conditioning apparatus according to Embodiment 2 of the present invention.
The air conditioning apparatus 50 shown in FIG. 11 includes a bypass pipe 13c, an opening / closing device 14 that is a solenoid valve, and a throttling device 15 that is a capillary, for example, as a stagnation correction device. Here, the bypass pipe 13c corresponds to the first recovery pipe of the present invention.

  The bypass pipe 13c includes a suction side of the compressor 1 (upstream side of the accumulator 9 in the case of the second embodiment) and a part of a path of the outdoor heat exchanger 4 (for example, a path disposed in the lower part). Are connected. The opening / closing device 14 opens and closes the flow path of the bypass pipe 13c, and is provided in the bypass pipe 13c. The expansion device 15 depressurizes the refrigerant flowing through the bypass pipe 13c, and is provided in the bypass pipe 13c. Further, the outdoor heat exchanger 4 of the air conditioner 50 shown in FIG. 11 is also provided with a thermistor 12 that detects the stagnation of the refrigerant.

  When refrigerant stagnation is detected based on the temperature detected by the thermistor 12, the refrigerant trapped in the outdoor heat exchanger 4 can be sucked by the compressor 1 by opening the opening / closing device 14. At this time, since the refrigerant in the bypass pipe 13c is depressurized (expanded) by the expansion device 15, liquid back to the compressor 1 can be prevented.

  As described above, by providing the stagnation correction device like the air conditioner 50 according to the second embodiment, it is possible to correct the stagnation of the refrigerant in the outdoor heat exchanger 4.

Embodiment 3 FIG.
During the heating operation, the gas-liquid two-phase refrigerant flows into the first pipe (for example, the outer pipe 18 in FIG. 2) of the second distribution header 10, and this refrigerant is distributed to each path. At this time, the pressure loss increases as the gas-liquid two-phase refrigerant flowing in from the lower part of the first pipe (for example, the outer pipe 18 in FIG. 2) flows above the first pipe (for example, the outer pipe 18 in FIG. 2). Increases dryness. For this reason, in heating operation, in order to suppress an increase in pressure loss of the refrigerant flowing through the first pipe (for example, the outer pipe 18 in FIG. 2), the second distribution header 10 may be configured as follows, for example. In the first embodiment, several configurations of the second distribution header 10 are shown (for example, FIG. 2 and FIGS. 6 to 8). In the third embodiment, the second distribution header 10 shown in FIG. Explained as an example. In the third embodiment, items that are not particularly described are the same as those in the first or second embodiment, and the same functions and configurations are described using the same reference numerals.

FIG. 12 is a schematic longitudinal sectional view showing an example of the second distribution header of the air-conditioning apparatus according to Embodiment 3 of the present invention.
The inner pipe 19 of the second distribution header 10 shown in FIG. 12 has a diameter along the flow direction of the refrigerant flowing in the outer pipe 18 when the outdoor heat exchanger 4 functions as an evaporator (that is, from the lower part to the upper part). Is getting smaller step by step. That is, the inner pipe 19 of the second distribution header 10 shown in FIG. 12 is along the flow direction of the refrigerant flowing through the outer pipe 18 when the outdoor heat exchanger 4 functions as an evaporator (that is, from the lower part to the upper part). The cross-sectional area of the channel is gradually reduced. Thereby, when the outdoor heat exchanger 4 functions as an evaporator, the flow path of the outer tube 18 can be increased stepwise along the flow direction of the refrigerant flowing through the outer tube 18 (that is, from the lower part to the upper part). For this reason, since it can suppress that a pressure loss increases as it goes above the outer tube | pipe 18, the dryness of the refrigerant | coolant in the entrance of each path | pass of the outdoor heat exchanger 4 can be equalized, and a refrigerant | coolant is distributed equally to each path | pass. can do. In addition, the inner pipe 19 shown in FIG. 12 has a stepped portion having a C-plane cut shape 30 in order to suppress an increase in pressure loss due to a sudden shape change at the stepped portion.

FIG. 13 is a schematic longitudinal sectional view showing another example of the second distribution header of the air-conditioning apparatus according to Embodiment 3 of the present invention.
The inner pipe 19 of the second distribution header 10 shown in FIG. 13 has a diameter along the flow direction of the refrigerant flowing through the outer pipe 18 when the outdoor heat exchanger 4 functions as an evaporator (that is, from the lower part to the upper part). Is asymptotically smaller (in other words, it has a Taber shape). That is, the inner pipe 19 of the second distribution header 10 shown in FIG. 13 is along the flow direction of the refrigerant flowing through the outer pipe 18 when the outdoor heat exchanger 4 functions as an evaporator (that is, from the lower part to the upper part). The cross-sectional area of the flow path is asymptotically reduced. Thereby, when the outdoor heat exchanger 4 functions as an evaporator, the flow path of the outer tube 18 can be asymptotically increased along the flow direction of the refrigerant flowing through the outer tube 18 (that is, from the lower part to the upper part). For this reason, since it can suppress that a pressure loss increases as it goes above the outer tube | pipe 18, the dryness of the refrigerant | coolant in the entrance of each path | pass of the outdoor heat exchanger 4 can be equalized, and a refrigerant | coolant is distributed equally to each path | pass. can do.

FIG. 14 is a schematic longitudinal sectional view illustrating still another example of the second distribution header of the air-conditioning apparatus according to Embodiment 3 of the present invention.
The outer pipe 18 of the second distribution header 10 shown in FIG. 14 has a diameter along the flow direction of the refrigerant flowing through the outer pipe 18 when the outdoor heat exchanger 4 functions as an evaporator (that is, from the lower part to the upper part). Is gradually increasing. That is, the outer pipe 18 of the second distribution header 10 shown in FIG. 14 is along the flow direction of the refrigerant flowing through the outer pipe 18 when the outdoor heat exchanger 4 functions as an evaporator (that is, from the lower part to the upper part). The cross-sectional area of the flow path is increased stepwise. For this reason, since it can suppress that a pressure loss increases as it goes above the outer tube | pipe 18, the dryness of the refrigerant | coolant in the entrance of each path | pass of the outdoor heat exchanger 4 can be equalized, and a refrigerant | coolant is distributed equally to each path | pass. can do. In addition, the outer tube 18 shown in FIG. 14 has a stepped portion having a C-plane cut shape 30 in order to suppress an increase in pressure loss due to a sudden shape change at the stepped portion.

FIG. 15 is a schematic longitudinal sectional view showing still another example of the second distribution header of the air-conditioning apparatus according to Embodiment 3 of the present invention.
The outer pipe 18 of the second distribution header 10 shown in FIG. 15 has a diameter along the flow direction of the refrigerant flowing through the outer pipe 18 when the outdoor heat exchanger 4 functions as an evaporator (that is, from the lower part to the upper part). Is asymptotically larger (in other words, a taber shape). That is, the outer pipe 18 of the second distribution header 10 shown in FIG. 15 is along the flow direction of the refrigerant flowing through the outer pipe 18 when the outdoor heat exchanger 4 functions as an evaporator (that is, from the lower part to the upper part). The cross-sectional area of the flow path increases asymptotically. For this reason, since it can suppress that a pressure loss increases as it goes above the outer tube | pipe 18, the dryness of the refrigerant | coolant in the entrance of each path | pass of the outdoor heat exchanger 4 can be equalized, and a refrigerant | coolant is distributed equally to each path | pass. can do.

  As described above, when the outdoor heat exchanger 4 functions as an evaporator, the flow path of the outer tube 18 is increased along the flow direction of the refrigerant flowing through the outer tube 18 (that is, from the lower part to the upper part). Thereby, the dryness of the refrigerant | coolant in the entrance of each path | pass of the outdoor heat exchanger 4 can be equalize | homogenized, and a refrigerant | coolant can be equally distributed to each path | pass.

  In the third embodiment, the diameter of one of the outer tube 18 and the inner tube 19 is changed. However, the diameters of both the outer tube 18 and the inner tube 19 may be changed. Moreover, also in the 2nd distribution header 10 shown in FIGS. 6-8 of Embodiment 1, each path | pass of the outdoor heat exchanger 4 is changed by changing the flow-path cross-sectional area of the 1st piping 24 as mentioned above. The degree of dryness of the refrigerant at the inlet can be made uniform, and the refrigerant can be evenly distributed to each path.

  1 compressor, 2 oil separator, 3 four-way valve, 4 outdoor heat exchanger (cooling: condenser, heating: evaporator), 5 first distribution header, 6 second distribution header, 7 throttling device, 8a branch piping, 8b Piping, 9 Accumulator, 10 Second distribution header, 12 Thermistor, 13 (13a, 13b) Bypass pipe, 13c Bypass pipe, 14 Opening / closing device, 15 Throttle device, 18 Outer pipe, 19 Inner pipe, 20 Distribution lead pipe, 21 Pass outlet, 22 High-pressure bypass pipe inlet, 23 Second pipe, 24 First pipe, 25 Throttle device, 26 Indoor heat exchanger (cooling: evaporator, heating: condenser), 27 Liquid side pipe, 29 Branch bypass pipe, 30 C surface cut shape, 50 air conditioner, 100 air conditioner (conventional), 107 throttle device (conventional), 108a branch pipe (conventional), 1 08b Piping (conventional), 110 Double pipe heat exchanger (conventional).

Claims (10)

Multiple paths through which the refrigerant flows;
A first distribution header connected to one end of the plurality of paths;
A second distribution header connected to the other end of the plurality of paths;
With
The second distribution header is
A first pipe connected to the other end of the plurality of paths;
A branch pipe for branching a part of the refrigerant flowing through the first pipe;
A second pipe that is connected to the branch pipe and that exchanges heat between the refrigerant flowing in from the branch pipe and the refrigerant flowing in the first pipe;
A first expansion device that is provided in the branch pipe and expands the refrigerant flowing into the second pipe;
Equipped with a,
The first pipe and the second pipe are arranged along the vertical direction,
The first pipe has a configuration in which the refrigerant flows from the lower part to the upper part of the first pipe in a state where the refrigerant is distributed from the first pipe to the plurality of paths.
The heat exchanger according to claim 1, wherein a cross-sectional area of the flow path of the first pipe is increased along a flow direction of the refrigerant flowing from the lower part to the upper part of the first pipe . Multiple paths through which the refrigerant flows;
A first distribution header connected to one end of the plurality of paths;
A second distribution header connected to the other end of the plurality of paths;
With
The second distribution header is
A first pipe connected to the other end of the plurality of paths;
A branch pipe for branching a part of the refrigerant flowing through the first pipe;
A second pipe that is connected to the branch pipe and that exchanges heat between the refrigerant flowing in from the branch pipe and the refrigerant flowing in the first pipe;
A first expansion device that is provided in the branch pipe and expands the refrigerant flowing into the second pipe;
Equipped with a,
The first pipe and the second pipe are arranged along the vertical direction,
The first pipe has a configuration in which the refrigerant flows from the lower part to the upper part of the first pipe in a state where the refrigerant is distributed from the first pipe to the plurality of paths.
The cross-sectional area of the flow path of the first pipe is reduced as the cross-sectional area of the flow path of the second pipe decreases along the flow direction of the refrigerant flowing from the lower part to the upper part of the first pipe. A heat exchanger characterized by increasing in the flow direction of the refrigerant flowing from the lower part to the upper part of the pipe . When the refrigerant flowing out from the plurality of paths is viewed along the flow direction when flowing through the first pipe,
The connection position of the branch pipe to the second pipe is as follows:
The heat exchanger according to claim 1 or 2 , wherein the heat exchanger is located at a position upstream of a downstream end of the second pipe. The flow direction of the refrigerant when the refrigerant flowing out from the plurality of paths flows through the first pipe and the flow direction of the refrigerant flowing through the second pipe are counterflows,
The second pipe is configured such that the refrigerant flowing into the second pipe flows out from the upper end of the second pipe.
A plurality of branch bypass pipes connected to the second pipe along the flow direction of the refrigerant in the second pipe;
The heat exchanger according to any one of claims 1 to 3, wherein the branch pipe is connected to the second pipe via a plurality of branch bypass pipes . The first pipe and the second pipe are:
The heat exchanger according to any one of claims 1 to 4 , wherein the heat exchanger is integrally formed by dividing the inside of the pipe member with a partition plate. The heat exchanger according to any one of claims 1 to 4 , wherein an outer peripheral surface of the second pipe is provided in contact with an inner peripheral surface of the first pipe. The heat exchanger according to any one of claims 1 to 4 , wherein an outer peripheral surface of the second pipe is provided in contact with an outer peripheral surface of the first pipe. In an air conditioner including a compressor, a flow path switching device, an outdoor heat exchanger, a second expansion device, and an indoor heat exchanger,
An air conditioner using the heat exchanger according to any one of claims 1 to 7 as an outdoor heat exchanger. A stagnation correction device that corrects the stagnation of refrigerant in the outdoor heat exchanger ;
A thermistor provided in the outdoor heat exchanger;
Equipped with a,
The sleep correction device
A bypass pipe having one end connected to the discharge side of the compressor and the other end connected to the suction side of the compressor through the outdoor heat exchanger;
When it is provided in the bypass pipe between the discharge side of the compressor and the outdoor heat exchanger, and when it is detected that the refrigerant has stagnated in the outdoor heat exchanger in operation based on the detected temperature of the thermistor An opening and closing device that opens and allows the refrigerant to flow through the bypass pipe;
A third expansion device provided in the bypass pipe between the outdoor heat exchanger and the suction side of the compressor;
Air conditioner according to claim 8, characterized in that with a. A stagnation correction device that corrects the stagnation of refrigerant in the outdoor heat exchanger ;
A thermistor provided in the outdoor heat exchanger;
Equipped with a,
The sleep correction device
A first recovery pipe connecting the suction side of the compressor and a part of the plurality of paths of the outdoor heat exchanger;
An opening / closing device that is provided in the first recovery pipe and opens when it is detected that the refrigerant has fallen into the outdoor heat exchanger that is operating based on the temperature detected by the thermistor, and flows the refrigerant through the first recovery pipe When,
A third expansion device provided in the first recovery pipe;
Air conditioner according to claim 8, characterized in that with a.

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