JP6641070B1 - Air conditioner - Google Patents

Abstract

An air conditioner including an indoor unit and an outdoor unit, wherein the indoor unit has an indoor heat exchanger, the outdoor unit has an expansion valve, and the indoor heat exchanger is provided with two rows of heat transfer tubes. A two-row heat exchanger, and a one-row heat exchanger on which one-row heat transfer tubes are arranged, wherein the expansion valve has at least a part of one row of the two-row heat exchanger and two rows. It is connected to the single-row heat exchanger via at least a part of the other row of the heat exchanger.

Description

  The present invention relates to an air conditioner having an indoor unit and an outdoor unit.

  An air conditioner has an outdoor unit and an indoor unit. Each of the outdoor unit and the indoor unit is provided with a heat exchanger for exchanging heat between air and a refrigerant, and a blower for generating a flow of air. During the cooling operation, a low-temperature refrigerant flows inside the heat exchanger provided in the indoor unit, and air inside the building flows outside the heat exchanger, thereby cooling the air inside the building. At this time, a part of the water vapor contained in the air in the building is cooled on the surface of the heat exchanger, so that dew condensation occurs. Condensed water on the surface of the heat exchanger is discharged from the drain hose to the outside through a drain pan via a fin of the heat exchanger and a drain pan.

  If the heat exchanger has a temperature distribution, some air may be excessively cooled and some air may be undercooled. When air having such a temperature difference is blown out of the heat exchanger, dew condensation may occur on the airflow path of the blowing unit of the indoor unit. Condensation on the air passage may be blown into the room from the outlet by the wind, or may be dropped into the room along the air passage. On the other hand, in Patent Document 1, a heat sensor is provided in a heat exchanger of an indoor unit in order to prevent dew condensation inside the indoor unit, and an expansion valve is controlled in accordance with the measured temperature to thereby control the heat exchanger. There is disclosed a technique for controlling such that a temperature difference does not occur inside. Further, from the viewpoint of cost reduction and compactness, application of a heat exchanger composed of a single-row heat exchanger and a double-row heat exchanger is desired.

JP-A-8-159538

  However, in a heat exchanger composed of a single-row heat exchanger and a two-row heat exchanger, air flows more easily in the first row than in the second row. For this reason, there is a problem that the air temperature after passing through the heat exchanger tends to be different.

  The present invention has been made in view of such a problem, and has as its object to prevent dew condensation inside an indoor unit while using a heat exchanger having a single-row heat exchanger and a two-row heat exchanger.

Therefore, the present invention is an air conditioner including an indoor unit and an outdoor unit, wherein the indoor unit has an indoor heat exchanger, the outdoor unit has an expansion valve, and the indoor heat exchanger is A two-row heat exchanger in which two rows of heat transfer tubes are arranged, and a one-row heat exchanger in which one row of heat transfer tubes are arranged, wherein the two-row heat exchanger is provided on a front surface of the indoor unit. Side, the single-row heat exchanger is disposed on the rear side of the indoor unit, and during a cooling operation, the expansion valve is at least a part of one row of the two-row heat exchanger, and The two-row heat exchanger is connected to the one-row heat exchanger via at least a part of the other row, and a flow path of the indoor heat exchanger is formed in one pass.
Another embodiment of the present invention is an air conditioner including an indoor unit and an outdoor unit, wherein the indoor unit has an indoor heat exchanger, the outdoor unit has an expansion valve, and the indoor heat exchange The heat exchanger includes a two-row heat exchanger in which two rows of heat transfer tubes are arranged, and a one-row heat exchanger in which one row of heat exchanger tubes is arranged. , The indoor heat exchanger has a first single-row heat exchanger and a second single-row heat exchanger, and the first single-row heat exchanger is And the second single-row heat exchanger is disposed below the double-row heat exchanger, and during cooling operation, the expansion valve is connected to one of the double-row heat exchangers. Connected to the single-row heat exchanger via at least a part of the row and at least a part of the other row of the two-row heat exchanger, wherein the flow path of the indoor heat exchanger is formed in one pass Is And said that you are.
Still another embodiment is an air conditioner including an indoor unit and an outdoor unit, wherein the indoor unit has an indoor heat exchanger, the outdoor unit has an expansion valve, and the indoor heat exchanger is A two-row heat exchanger in which two rows of heat transfer tubes are arranged, and a one-row heat exchanger in which one row of heat transfer tubes are arranged, wherein the two-row heat exchanger is provided on a front surface of the indoor unit. , The single-row heat exchanger is disposed on the rear side of the indoor unit, and during cooling operation, the expansion valve is connected to the single-row heat exchanger via at least a part of the double-row heat exchanger. And the pipes are connected so that the temperature of the connecting portion between the single-row heat exchanger and the double-row heat exchanger becomes a temperature determined according to the dew point temperature, and the indoor heat exchange is performed. The flow path of the vessel is formed in one pass.
Still another embodiment is an air conditioner including an indoor unit and an outdoor unit, wherein the indoor unit has an indoor heat exchanger, the outdoor unit has an expansion valve, and the indoor heat exchanger is A two-row heat exchanger in which two rows of heat transfer tubes are arranged, a first one-row heat exchanger in which one row of heat transfer tubes is arranged, and a second one-row heat in which one row of heat exchanger tubes are arranged An air conditioner, wherein the two-row heat exchanger is disposed on the front side of the indoor unit, the first single-row heat exchanger is disposed on the rear side of the indoor unit, The single-row heat exchanger is disposed below the double-row heat exchanger, and during a cooling operation, the expansion valve is connected to the first single-row heat exchanger via at least a part of the double-row heat exchanger. is connected to a vessel and the second one column heat exchanger, the two rows heat exchanger is determined temperature of the connecting portion before Symbol said one column heat exchanger and the second row heat exchanger according to the dew point temperature Warm Plumbed so that the flow path of the indoor heat exchanger is characterized in that it is formed in one pass.
Another embodiment is an air conditioner including an indoor unit and an outdoor unit, wherein the indoor unit has an indoor heat exchanger, and the indoor heat exchanger has two rows of heat transfer tubes. A row heat exchanger, and a single row heat exchanger on which a single row of heat transfer tubes are arranged, wherein the double row heat exchanger is disposed on the front side of the indoor unit, and the single row heat exchanger Is disposed on the rear side of the indoor unit, the outdoor unit has an expansion valve, and during the cooling operation, the expansion valve is configured so that the entire flow of the two-row heat exchanger in the two-row heat exchanger The passage is connected to the single-row heat exchanger through at least half of the passages, and the passage of the indoor heat exchanger is formed in one pass.
Another embodiment is an air conditioner including an indoor unit and an outdoor unit, wherein the indoor unit has an indoor heat exchanger, and the indoor heat exchanger has two rows of heat transfer tubes. A row heat exchanger, a first single-row heat exchanger in which a single row of heat transfer tubes are arranged, and a second single-row heat exchanger in which a single row of heat transfer tubes are arranged; The row heat exchanger is arranged on the front side of the indoor unit, the first single-row heat exchanger is arranged below the double-row heat exchanger, and the second single-row heat exchanger is The outdoor unit has an expansion valve, which is disposed on the back side of the indoor unit. When the cooling operation is performed, the expansion valve is disposed in the two-row heat exchanger in the entire flow path of the two-row heat exchanger. Of the indoor heat exchanger are connected to the first single-row heat exchanger and the second single-row heat exchanger through at least half of the flow paths. Being And it features.
Still another embodiment is an air conditioner including an indoor unit and an outdoor unit, wherein the indoor unit has an indoor heat exchanger, the outdoor unit has an expansion valve, and the indoor heat exchanger is , M (m is an integer of 2 or more) rows of heat transfer tubes, and n (n is an integer of 1 or more and less than m) rows of heat exchangers. Wherein the m-row heat exchanger is disposed on the front side of the indoor unit, and the n-row heat exchanger is disposed on the back side of the indoor unit, and the cooling valve operates during the cooling operation. Is connected to the n-row heat exchanger via at least a part of the first row of the m-row heat exchanger and at least a part of the second row of the m-row heat exchanger, and The flow path of the vessel is formed in one pass.
Still another embodiment is an air conditioner including an indoor unit and an outdoor unit, wherein the indoor unit has an indoor heat exchanger, the outdoor unit has an expansion valve, and the indoor heat exchanger is , M (m is an integer of 2 or more) rows of heat transfer tubes, and n (n is an integer of 1 or more and less than m) rows of first heat exchangers. a column heat exchanger, and a second n rows heat exchanger heat transfer tube of the n rows is arranged, has the m column heat exchanger is disposed on the front side of the indoor unit, the first The n-row heat exchanger is disposed below the m-row heat exchanger, the second n-row heat exchanger is disposed on the back side of the indoor unit, and during the cooling operation, the expansion valve is Via at least a portion of a first row of the m-row heat exchanger and at least a portion of a second row of the m-row heat exchanger, the first n-row heat exchanger and the second n Row heat Is connected to the exchanger, the flow path of the indoor heat exchanger is characterized in that it is formed in one pass.

  Advantageous Effects of Invention According to the present invention, it is possible to prevent dew condensation inside an indoor unit while using a heat exchanger having a single-row heat exchanger and a two-row heat exchanger.

It is a figure showing the structure of an indoor unit. It is sectional drawing of an indoor heat exchanger. It is a figure which shows the modification of an indoor heat exchanger. FIG. 1 is an overall configuration diagram of an air conditioner. It is sectional drawing of the indoor heat exchanger which concerns on 2nd Embodiment. It is sectional drawing of the indoor heat exchanger which concerns on 3rd Embodiment. It is sectional drawing of the indoor heat exchanger which concerns on 4th Embodiment. It is a figure showing the heat exchanger concerning a comparative example. It is a figure showing the heat exchanger concerning a comparative example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments, and various modifications and application examples are included in the technical concept of the present invention. Is included in the range.

(First embodiment)
FIG. 1 is a diagram illustrating a structure of an indoor unit 100 of the air conditioner according to the first embodiment. FIG. 1 is a cross-sectional view perpendicular to the rear surface 120 of the indoor unit 100 and parallel to the vertical direction of the indoor unit 100. Hereinafter, the x-axis direction (the depth direction of the paper) in the three-dimensional coordinates as shown in FIG. 1 is the horizontal direction of the indoor unit 100, and the y-axis direction (the vertical direction of the paper) is the vertical direction of the indoor unit 100 (the upper side of the paper is upward). Direction) and the z-axis direction (horizontal direction on the paper) are defined as the depth direction of the indoor unit 100.

  The indoor unit 100 is installed near the ceiling of the room such that the rear surface 120 faces the wall A. In FIG. 1, a room as a space to be air-conditioned extends on the lower left side of the drawing, and the indoor unit 100 has a structure in which air flows so as to adjust the temperature of the room.

  Inside the indoor unit 100, an indoor heat exchanger 110 and an indoor fan 102 are mounted. In the indoor heat exchanger 110, heat is exchanged by blowing air from the indoor fan 102. The indoor unit 100 is further provided with a filter device 103, a back casing 104, a front casing 105, a louver 106, and a vertical louver 107.

  The air is sucked into the indoor unit 100 from the upper side of FIG. 1, that is, the upper side of the indoor unit 100, and large dust and the like are removed by the filter device 103, and passes through the indoor heat exchanger 110. The indoor fan 102 blows air to the indoor heat exchanger 110. As the indoor fan 102, a once-through fan can be used. When a once-through fan is used, a front nose 109 is provided on the front side of the indoor fan 102, and a back nose 108 is provided on the rear side (back side 120 side). The front nose 109 and the back nose 108 separate the air suction side and the air blowing side of the indoor fan 102, and the indoor fan 102 exhibits a blowing function.

  When sucking air from above the indoor heat exchanger 110 and flowing air to the space below as shown in FIG. 1, the indoor fan 102, as shown in FIG. Rotate clockwise. After being blown out by the indoor fan 102, the air passes through the air path formed by the front nose 109 and the back casing 104, and further flows out into the room with the blowing direction controlled by the louver 106 and the vertical louver 107. The louver 106 controls the wind direction of the blowing wind in the vertical direction. The vertical louver 107 controls the wind direction in the horizontal direction (left-right direction).

  The indoor heat exchanger 110 has a heat transfer tube through which the refrigerant flows, and fins connected around the heat transfer tube. In FIG. 1, a plurality of circles 110a shown inside the indoor heat exchanger 110 indicate heat transfer tubes. The heat transfer tube extends in the depth direction, and is connected at the right end or the left end by a U-shaped tube, thereby forming one flow path (one pass) of the refrigerant. The fins are aluminum plates having a thickness of about 0.1 mm, and are arranged in a horizontal direction of the indoor heat exchanger 110 at intervals of about 1 mm. The fins and the heat transfer tube are in close contact, and the refrigerant passes through the inside of the heat transfer tube.

  In the cooling operation, the outdoor unit 200 supplies a refrigerant having a temperature lower than the indoor air temperature to the indoor heat exchanger 110. The temperature of the fins of the indoor heat exchanger 110 is close to the temperature of the supplied refrigerant. The warm air in the room is flown by the indoor fan 102 and cooled by the indoor heat exchanger 110. When the temperature of the fins of the indoor heat exchanger 110 is lower than the dew point of the indoor air flowing through the indoor heat exchanger 110, moisture in the air condenses on the fin surfaces of the indoor heat exchanger 110. The condensed water flows below the indoor heat exchanger 110 via the fins, flows along a drain flow path provided inside the casing, and flows out of the room. As described above, when the cooling operation is performed, moisture in the air may condense in the indoor heat exchanger 110. Further, the air that has passed through the indoor heat exchanger 110 is cooled by the indoor heat exchanger 110 and a part of moisture is condensed, but the relative humidity is kept close to 100%.

  FIG. 2 is a diagram showing the structure of the indoor heat exchanger 110. The indoor heat exchanger 110 includes a two-row heat exchanger 111, a front-side single-row heat exchanger 112, and a back-side single-row heat exchanger 113. The two-row heat exchanger 111 is provided on the upper front side of the indoor unit 100 so that two rows of heat transfer tubes are arranged along the depth direction. In the two-row heat exchanger 111, two rows of heat transfer tubes are arranged along the direction in which air flows when the indoor fan 102 is driven. The front row, that is, the row on the windward side of the two-row heat exchanger 111 is referred to as a windward row 1111. The rear row, that is, the leeward row of the two-row heat exchanger 111 is referred to as a leeward row 1112. The front-side single-row heat exchanger 112 is disposed so as to extend downward from below the double-row heat exchanger 111. The rear-side single-row heat exchanger 113 is arranged to extend from the upper side of the double-row heat exchanger 111 to the rear side. The lowermost stage 111a of the two-row heat exchanger 111, which serves as a refrigerant inlet during the cooling operation, is connected to an expansion valve of an outdoor unit via a pipe. Further, the lowermost stage 13b of the rear heat exchanger 113 serving as an outlet for cooling during cooling operation is connected to a four-way valve of the outdoor unit via a pipe.

  The indoor heat exchanger 110 of the present embodiment thus has a single row. In a conventional heat exchanger, a double-row heat exchanger is often used on both the front side and the rear side. On the other hand, in the indoor heat exchanger 110 of the present embodiment, the material of the heat exchanger is reduced by forming a part of the front side and the back side into a single-row heat exchanger. As a result, not only effective use of resources but also compactness and energy saving can be expected.

  However, in the first row and the second row, the ventilation resistance of air at the same wind speed is about twice different. Therefore, if simply considered from the wind speed, the amount of air passing through the single-row heat exchanger and the amount of air passing through the two-row heat exchanger may differ by about 1.4 times. Note that, since the air is actually sucked from the ceiling side (upper side) of the indoor unit 100, in the arrangement of the indoor heat exchanger 110 shown in FIG. The front-side single-row heat exchanger 112 located below the position is harder to suck in air. For this reason, it is considered that the difference in air volume is smaller than 1.4 times. Also in the back side single-row heat exchanger 113, the back nose 108 can be a wall that obstructs the flow from the back side single-row heat exchanger 113 to the indoor fan 102. For this reason, even in the back side single-row heat exchanger 113, it is difficult to suck in air as compared with the two-row heat exchanger 111. That is, the two-row heat exchanger 111 has a higher heat exchange efficiency than the front-side single-row heat exchanger 112 and the rear-side single-row heat exchanger 113.

  Further, as described above, the indoor heat exchanger 110 of the present embodiment has one refrigerant path that does not branch off in the middle. This corresponds to the fact that when using a flammable refrigerant, it is desirable that the refrigerant path in the heat exchanger is simple, and that the smaller the number of brazing parts due to branching or the like can reduce the risk of leakage. . Examples of the flammable refrigerant include propane (R290). Examples of the slightly flammable refrigerant include difluoromethane (R32) and 2,3,3,3-tetrafluoropropene (R1234yf).

  Further, in the present embodiment, the heat transfer tube is formed of aluminum or an aluminum alloy. As described above, when aluminum or an aluminum alloy is used for the heat transfer tube, the brazing property is not good as compared with a copper tube or the like. Therefore, reducing the number of brazed portions leads to an improvement in the productivity of the heat exchanger. Aluminum is considered to have more reserves than copper, and it may be effective to reduce the copper used and replace it with aluminum in order to achieve a sustainable society. In addition, a portion where the aluminum tube and the copper tube are joined may be corroded when dew condensation occurs. Therefore, it is desirable that unnecessary condensation does not occur. For the above reasons, one pass is adopted for the two-row heat exchanger 111 according to the present embodiment.

  During the cooling operation, the refrigerant has a large liquid phase near the inlet of the two-row heat exchanger 111, and when passing through the two-row heat exchanger 111, the liquid phase in the refrigerant evaporates, and Cool down. Therefore, when passing through the two-row heat exchanger 111, the gas phase in the refrigerant increases. Therefore, the speed of the refrigerant in the refrigerant flow path in the two-row heat exchanger 111 also increases. In a conventional heat exchanger, a branch is provided in a pipe in the heat exchanger, and a refrigerant pressure loss inside the two-row heat exchanger has been reduced by dividing and flowing the refrigerant. On the other hand, in the two-row heat exchanger 111 of the present embodiment, since one pass is employed, the acceleration of the refrigerant due to the pressure loss is greater than in the case where two passes are employed. As the pressure loss increases, the pressure in the second half of the flow path of the two-row heat exchanger 111 decreases compared to the first half, and the saturation temperature also decreases accordingly. Thereby, the temperature difference of the refrigerant inside the heat exchanger increases. In contrast, the indoor heat exchanger 110 of the present embodiment can prevent dew condensation due to this temperature difference with the following configuration.

  The arrows shown in FIG. 2 indicate the flow of the refrigerant during the cooling operation. During the cooling operation, the refrigerant which has been decompressed by the expansion valve of the outdoor unit to be described later and is in a low-temperature two-phase state has a two-row heat exchanger with the lowest stage 111a of the upwind row 1111 of the two-row heat exchanger 111 as an inlet. It flows into 111. Thereafter, the refrigerant flows in the leeward row 1111 in a direction opposite to the direction of gravity, that is, upwards, and after flowing to the uppermost stage 111b, flows into the leeward row 1112 thereafter. In the leeward row 1112, the refrigerant flows downward from the uppermost stage 111c, flows to the lowermost stage 111d, and subsequently flows into the uppermost stage 112a of the front-side single-row heat exchanger 112. In the front-side single-row heat exchanger 112 as well, the refrigerant flows downward, and when flowing to the lowermost stage 112b, flows into the rear-side single-row heat exchanger 113. In the rear-side single-row heat exchanger 113, the refrigerant flows downward from the uppermost stage 113a to the lowermost stage 113b, and flows out using the lowermost stage 113b as an outlet.

  In the above configuration, the refrigerant on the cooling inlet side of the indoor heat exchanger 110 exchanges heat with air in the two-row heat exchanger 111 having a large heat transfer area. Further, the refrigerant whose temperature has decreased by passing through the two-row heat exchanger 111 exchanges heat with air in the front-side single-row heat exchanger 112 and the rear-side single-row heat exchanger 113 having small heat transfer areas. Thereby, the air temperature after passing through the indoor heat exchanger 110 can be made uniform. That is, it is possible to suppress the occurrence of dew condensation in the ventilation path at the subsequent stage of the indoor heat exchanger 110.

  In addition, it is preferable that the refrigerant flowing out of the two-row heat exchanger 111 flows into a position as close as possible to the two-row heat exchanger 111 among the front-side single-row heat exchanger 112 and the rear-side single-row heat exchanger 113. . From this viewpoint, in the present embodiment, in both the front-side single-row heat exchanger 112 and the rear-side single-row heat exchanger 113, the refrigerant is piped so as to flow into the uppermost stages 112a and 113a.

  Further, FIG. 2 shows the flow of the refrigerant during the cooling operation, but the flow of the refrigerant during the heating operation is opposite to that during the cooling operation. During the heating operation, the pipe that has become the refrigerant inlet during cooling becomes the outlet. In the heating operation, the gas refrigerant flows into the indoor heat exchanger 110 and is liquefied by warming the air. At the heating outlet of the indoor heat exchanger 110, the refrigerant is cooled, becomes almost liquid, and flows out at a lower temperature than the inlet. Therefore, in order to transfer the heat to the air while making the temperature difference between the air and the air as large as possible, the windward side in contact with the air that has not passed through the indoor heat exchanger 110 is preferable. Further, when the path on the heating outlet side flows from the upper stage to the lower stage along the gravity, the liquid flows more easily, and the stagnation of the refrigerant can be suppressed. From these viewpoints, the indoor heat exchanger 110 of the present embodiment sets the outlet during heating, that is, the heat exchange inlet during cooling as the lowermost stage 111a of the windward row 1111 of the two-row heat exchanger 111, and the upper stage from there. Flow to

  Further, the lowermost stage 112b of the front-side single-row heat exchanger 112 and the uppermost stage 113a of the rear-side single-row heat exchanger 113 are connected by piping. This piping also contributes to pressure loss. Therefore, this pipe is made thicker than the other pipes. Furthermore, in order to avoid heat exchange with the air other than the blown air, it is covered with a heat insulating material.

  FIG. 8 is a diagram illustrating a heat exchanger 800 according to a comparative example. The heat exchanger 800 includes a two-row heat exchanger 801, a front-side single-row heat exchanger 802, and a back-side single-row heat exchanger 803, similarly to the indoor heat exchanger 110 of the present embodiment. I have. The front-side single-row heat exchanger 802 is provided below the double-row heat exchanger 801, and the rear-side single-row heat exchanger 803 is provided on the rear side so as to extend from above the double-row heat exchanger 801. ing.

  In the heat exchanger 800, the refrigerant flows into the heat exchanger 800 with the lowermost stage 801a of the upwind row 8011 of the two-row heat exchanger 801 as an inlet. Thereafter, the refrigerant flows upward in the windward row 8011 and flows to the uppermost stage 801b, and then flows into the lowermost stage 802a of the front-side single-row heat exchanger 802. After flowing upward from the lowermost stage 802a to the uppermost stage 802b, the refrigerant further flows upward from the lowermost stage 801c of the leeward row 8012 of the two-row heat exchanger 801 to the uppermost stage 801d. Thereafter, the refrigerant flows downward from the uppermost stage 803a to the lowermost stage 803b of the back-side single-row heat exchanger 803.

  In the above configuration, the temperature of the refrigerant near the cooling inlet side is not sufficiently lowered, and therefore, the front-side single-row heat exchanger through which the refrigerant that has passed only one row of the two-row heat exchanger 801 flows. In 802, sufficient heat exchange cannot be performed, and cooling and dehumidification become insufficient. On the other hand, especially in the vicinity of the uppermost stage 801d of the leeward row 8012 of the two-row heat exchanger 801, the temperature is remarkably reduced as compared with the other parts because of the two-row portion and the flow of the cooled refrigerant. Therefore, the cold air near the leeward row 8012 and the warm air near the front-side single-row heat exchanger 802 are mixed, and this may cause dew condensation in the ventilation path.

  On the other hand, as shown in FIG. 2, in the indoor heat exchanger 110 of the present embodiment, piping that flows into the front-side single-row heat exchanger 112 after passing through all the two-row heat exchangers 111 is used. did. Thereby, the refrigerant at the cooling inlet side, which has a relatively high temperature, flows through the two-row heat exchanger 111 that easily lowers the temperature of the air. Then, the cooled refrigerant flows through the front-side single-row heat exchanger 112 and the rear-side single-row heat exchanger 113. Thereby, the difference in air temperature in the entire indoor heat exchanger 110 can be reduced.

  FIG. 3 is a diagram showing a modification of the indoor heat exchanger 110. FIG. 9 is a diagram showing a comparative example corresponding to the modification shown in FIG. In the example shown in FIG. 3, the refrigerant flows through the two-row heat exchanger 111, flows through the front-side single-row heat exchanger 112, and then flows into the lowermost stage 113b of the back-side single-row heat exchanger 113. It flows upward to the upper stage 113a. As described above, the inlet of the refrigerant to the single-row heat exchanger does not necessarily have to be provided at a position closest to the double-row heat exchanger.

  On the other hand, in the heat exchanger 900 of the comparative example shown in FIG. 9, the refrigerant flows downward from the uppermost stage 901 a to the lowermost stage 901 b of the two-row heat exchanger 901, and before flowing into the leeward side, the front side. It enters the lowermost stage 902a of the single-row heat exchanger 902 and flows upward to the uppermost stage 902b. Thereafter, the refrigerant flows from the lowermost stage 901c on the leeward side of the two-row heat exchanger 901 to the uppermost stage 901d, and then flows from the uppermost stage 903a of the back-side single-row heat exchanger 113 to the lowermost stage 903b.

  In the indoor heat exchanger 110 according to the modification shown in FIG. 3, the cooling inlet temperature is 16.2 ° C., and the temperature of the uppermost stage 111c of the two-row heat exchanger 111 is 15.7 based on theoretical calculations under the rated cooling condition. ° C, the temperature of the lowermost stage 112b of the front-side single-row heat exchanger 112 is 14.5 ° C, and the temperature of the uppermost stage 113a of the rear-side single-row heat exchanger 113, that is, the outlet temperature is 13.2 ° C. On the other hand, in the heat exchanger 900 according to the comparative example shown in FIG. 9, the cooling inlet temperature is 16.3 ° C., the temperature of the lowermost stage 902a of the front-side single-row heat exchanger 902 is 15.8 ° C., and the temperature of the uppermost stage 902b is The temperature is 15.3 ° C., the temperature of the uppermost stage 901d of the two-row heat exchanger 901 is 14.3 ° C., and the temperature of the lowermost stage 803b of the back-side single-row heat exchanger 903, ie, the outlet temperature is 13.1 ° C.

  As described above, in the comparative example, the lowermost stage 902a of the front-side single-row heat exchanger 902 is insufficiently cooled and dehumidified, whereas the uppermost stage 901d is excessively cooled. On the other hand, in the indoor heat exchanger 110 according to the modified example, the temperature of the uppermost stage 112a of the front-side single-row heat exchanger 112 is lower than the corresponding position (the lowermost stage 902a) of the comparative example. It turns out that it is cooled sufficiently. Further, in the indoor heat exchanger 110 according to the modified example, the temperature of the uppermost stage 111c of the two-row heat exchanger 111 is higher than the corresponding position (the uppermost stage 901d) of the comparative example, and excessive cooling is eliminated. You can see that it is. As described above, in the present embodiment, dew condensation inside the indoor unit 100 can be prevented while using the indoor heat exchanger 110 having the single-row heat exchanger and the double-row heat exchanger.

  FIG. 4 is an overall configuration diagram of the air conditioner 10 including the indoor unit 100. The air conditioner 10 includes an indoor unit 100 and an outdoor unit 200. The indoor unit 100 and the outdoor unit 200 are connected by a refrigerant connection pipe. The outdoor unit 200 includes a four-way valve 201, a compressor 202, an accumulator 203, an expansion valve 204, an outdoor heat exchanger 205, and an outdoor fan 206.

  The arrow 12 indicates the direction in which the refrigerant flows during the heating operation. During the heating operation, a high-temperature, high-pressure gas refrigerant is supplied from the outdoor unit 200 to the indoor unit 100. The refrigerant flowing through the indoor heat exchanger 110 warms indoor air supplied by the indoor fan 102. Conversely, the gas refrigerant is cooled by the low-temperature air and condenses, and becomes a high-pressure liquid refrigerant. The refrigerant liquefied in the indoor unit 100 flows toward the outdoor unit 200 and reaches the expansion valve 204.

  The high-pressure liquid refrigerant is decompressed and cooled to a low temperature by the expansion valve 204 to form a gas-liquid two-phase flow. The low-pressure, low-temperature refrigerant reaches the outdoor heat exchanger 205. Outdoor air is passed through the outdoor heat exchanger 205 by the outdoor fan 206. Since the refrigerant is depressurized by the expansion valve 204 so as to have a lower temperature than the outside air, the refrigerant is heated by the outside air in the outdoor heat exchanger 205, and the liquid refrigerant evaporates to become a gas refrigerant.

  The low-temperature, low-pressure refrigerant gasified in the outdoor heat exchanger 205 reaches the four-way valve 201. At this time, the four-way valve 201 is switched such that the gas refrigerant flowing out of the outdoor heat exchanger 205 is returned to the suction side of the compressor 202 via the accumulator 203. The low-temperature, low-pressure gas refrigerant reaches the compressor 202 from the four-way valve 201 via the accumulator 203. The accumulator 203 has a function of preventing a large amount of liquid refrigerant from flowing into the compressor 202.

  Arrow 11 indicates the direction in which the refrigerant flows during cooling. The compressor 202 compresses a low-pressure, low-temperature refrigerant and discharges a high-temperature, high-pressure gas refrigerant. The high-temperature, high-pressure gas refrigerant discharged from the compressor 202 reaches the four-way valve 201. The four-way valve 201 is switched so that the gas refrigerant flowing from the compressor 202 flows to the outdoor heat exchanger 205 side. In the case of the cooling operation, a high-temperature and high-pressure gas refrigerant flows into the outdoor heat exchanger 205. By flowing outdoor air having a lower temperature than the gas refrigerant to the outdoor heat exchanger 205, the outdoor heat exchanger 205 cools and condenses the gas refrigerant and changes its phase to a liquid refrigerant. In the outdoor heat exchanger 205, the refrigerant in which some or all of the gas refrigerant has been liquefied reaches the expansion valve 204, where the pressure is reduced. When the pressure is reduced, a part of the refrigerant is gasified, and the heat of vaporization lowers the temperature of the refrigerant. Then, the low-temperature refrigerant flows to the indoor unit 100 through the refrigerant connection pipe.

  The amount of pressure reduction of the refrigerant at the expansion valve 204 can be adjusted by the degree of opening of the valve inside the expansion valve 204. The smaller the degree of opening, the greater the amount of pressure reduction and the lower the temperature of the refrigerant. On the other hand, if the degree of opening is increased, the pressure reduction amount is reduced, and the decrease in the temperature of the refrigerant is reduced. Under the cooling operation condition, the opening degree of the expansion valve 204 is adjusted so that the temperature of the refrigerant reaching the indoor unit 100 is lower than the indoor air temperature.

  As a first modified example, the indoor heat exchanger 110 is configured such that the refrigerant passes through at least a part of the leeward row 1111 and at least a part of the leeward row 1112 of the two-row heat exchanger 111, and It is sufficient that the pipes are connected so as to flow into the row heat exchanger 112 or the back-side single-row heat exchanger 113, and other pipe states are not limited to the embodiment.

  For example, the refrigerant passes through a part of the leeward row 1111, then passes through all the heat transfer tubes of the leeward row 1112, and then passes through the remaining flow paths of the leeward row 1111 again, and then passes through the front side row 1 The pipe may be provided so as to flow into the heat exchanger 112 or the back-side single-row heat exchanger 113. Further, for example, piping may be provided so that the refrigerant passes through the rear-side single-row heat exchanger 113 after passing through the two-row heat exchanger 111, and then flows into the front-side single-row heat exchanger 112. . In addition, for example, the refrigerant flows into the front-side single-row heat exchanger 112 with the uppermost stages 111b and 111c of the two-row heat exchanger 111 remaining, and thereafter, the uppermost stages 111b and 111c of the two-row heat exchanger 111 After passing through, the pipes may flow so as to flow to the rear-side single-row heat exchanger 113.

  However, from the viewpoint of preventing dew condensation, when flowing from the two-row heat exchanger 111 to the front-side single-row heat exchangers 112 and 113, the refrigerant needs to be sufficiently cooled, and the refrigerant temperature is close to the dew point temperature. Preferably, it has been cooled down. Therefore, the indoor heat exchanger 110 passes through the two-row heat exchanger 111 so that the connection between the front-side one-row heat exchanger 112 and the two-row heat exchanger 111 has a temperature determined according to the dew point temperature. It is assumed that a flow path from the two-row heat exchanger to the one-row heat exchanger is piped. Here, the connection portion is a region from the two-row heat exchanger 111d to the uppermost stage 112a of the one-row heat exchanger 112. Further, the temperature determined according to the dew point temperature may be the dew point temperature, or may be a value higher or lower by a certain temperature than the dew point temperature. Further, the temperature determined according to the dew point temperature may have a predetermined temperature range.

  In addition, from the viewpoint of preventing dew condensation, the refrigerant may flow into the single-row heat exchanger 111 after passing through half or more of all the flow paths of the indoor heat exchanger 110 in the two-row heat exchanger 111. In the flow path of the two-row heat exchanger 111, the expansion valve and the front-side heat exchanger 112 may be connected via a flow path that is at least half the distance of the entire flow path of the indoor heat exchanger 110. Good.

  As a second modification, the indoor heat exchanger 110 may have a plurality of heat exchangers having different numbers of rows, and the combination of the numbers of rows is not limited to the embodiment. For example, the indoor heat exchanger 110 may have a three-row heat exchanger and a two-row heat exchanger. Also in this case, the indoor heat exchanger 110 passes through a heat exchanger having a smaller number of rows after the refrigerant first passes through a heat exchanger having a larger number of rows and passes through a distance to be cooled to a temperature near the dew point temperature. Pipes shall be provided so as to flow into the exchanger. Further, for example, a heat exchanger having three or more rows such as a three-row heat exchanger, a two-row heat exchanger, and a one-row heat exchanger may be provided. Also in this case, it is assumed that the indoor heat exchanger 110 is piped such that the refrigerant passes from the heat exchanger having the larger number of rows in the order corresponding to the number of rows.

(Second embodiment)
Next, the differences between the indoor heat exchanger 110 according to the second embodiment and the indoor heat exchanger 110 according to the first embodiment will be mainly described. FIG. 5 is a cross-sectional view of the indoor heat exchanger 110 according to the second embodiment. In the indoor heat exchanger 110 according to the second embodiment, the refrigerant flows into the two-row heat exchanger 111 through one flow path and branches into two flow paths (two passes) in the two-row heat exchanger 111. I do. The expansion valve and the lowermost stage 111a of the two-row heat exchanger 111 are connected via piping, and the refrigerant flows into the lowermost stage 111a of the two-row heat exchanger 111 as shown in FIG. The flow path flowing upward from the lowermost stage 111a is branched into two flow paths in the third stage 111e from the top of the windward row 1111. One flow path moves from the third stage 111e to the upper stage 111f and the uppermost stage 111b, and then flows to the second stage 111g from the top of the leeward row 1112, then to the uppermost stage 111c, and then to the rear side 1st. This is a flow path that flows from the uppermost stage 113a of the row heat exchanger 113 to the lowermost stage 113b. The other flow path flows from the third stage 111 e from the top of the leeward row 1111 to the third stage 111 h from the top of the leeward row 1112, and then flows downward in the leeward row 1112, and furthermore, heat in the front side row This is a flow path that flows from the uppermost stage 112a of the exchanger 112 to the lowermost stage 112b.

  As described above, by using the two-pass configuration, the pressure loss of the refrigerant in the heat transfer tubes of the indoor heat exchanger 110 is reduced. However, since the pressure loss is not zero, the refrigerant temperature on the inlet side is high and the refrigerant temperature on the refrigerant outlet side is low. Therefore, in this two-pass configuration, a path is first provided in which the refrigerant flows through the two-row heat exchanger 111, and then flows through the front-side single-row heat exchanger 112 or the rear-side one-row heat exchanger 113. . Thus, after branching into two passes, a sufficiently cooled refrigerant can flow in both the front-side single-row heat exchanger 112 and the rear-side single-row heat exchanger 113. Therefore, the insufficient cooling of the air can be resolved, and the temperature difference between the air passing through the indoor heat exchanger 110 can be reduced.

  As a modified example of the second embodiment, the branch position and the flow path after the branch are not limited to the embodiment. However, it is preferable that the branch position is in the two-row heat exchanger 111. Further, it is preferable that the branch position is determined so that the distance of each path after the branch becomes equal. Also, in the indoor heat exchanger 110 of the second embodiment, the outlet of the indoor heat exchanger 110 is provided in the front-side single-row heat exchanger 112 or the rear-side single-row heat exchanger 113. .

(Third embodiment)
Next, the differences between the indoor heat exchanger according to the third embodiment and the indoor heat exchanger according to the other embodiments will be mainly described. FIG. 6 is a cross-sectional view of the indoor heat exchanger 210 according to the third embodiment. The indoor heat exchanger 210 according to the third embodiment is different from the indoor heat exchanger 110 according to the first embodiment in that the two-row heat exchanger 111 and the front-side single-row heat exchanger 112 are replaced by a front upper part. It has a two-row heat exchanger 221 integrally provided to the lower part.

  Also in such a configuration, the refrigerant that has flowed into the indoor heat exchanger 210 during the cooling operation first passes through the two-row heat exchanger 221 and is then piped to flow the refrigerant to the back-side single-row heat exchanger 222. I have. The flow path of the refrigerant is one pass. In the indoor heat exchanger 210 of the present embodiment, during the cooling operation, first, the refrigerant flows into the two-row heat exchanger 221 with the lowest stage 221a of the upwind row 2211 of the two-row heat exchanger 221 as the inlet. Thereafter, the refrigerant flows upward from the lowermost stage 221a to the uppermost stage 221b, and subsequently flows downward from the uppermost stage 221c of the leeward row 2212 to the lowermost stage 221d. Thereafter, the refrigerant flows into the uppermost stage 222a of the back-side single-row heat exchanger 222, flows downward to the lowermost stage 222b, and flows out using the lowermost stage 222b as an outlet.

  In the indoor heat exchanger 210 according to the third embodiment, similarly to the indoor heat exchangers in the other embodiments, the refrigerant first flows into the two-row heat exchanger 221 and all of the two-row heat exchanger 221 After passing through the flow path, the refrigerant flows into the back-side single-row heat exchanger 222. That is, the sufficiently cooled refrigerant flows into the back-side single-row heat exchanger 222. Therefore, the temperature difference of the air that has passed through the indoor heat exchanger 210 can be reduced, and dew condensation can be prevented.

(Fourth embodiment)
Next, the differences between the indoor heat exchanger 210 according to the fourth embodiment and the indoor heat exchanger 210 according to the third embodiment will be mainly described. FIG. 7 is a cross-sectional view of the indoor heat exchanger 210 according to the fourth embodiment. In the indoor heat exchanger 210 according to the fourth embodiment, the refrigerant flows into the two-row heat exchanger 221 through one flow path, and branches into two flow paths in the two-row heat exchanger 221.

  As shown in FIG. 7, the refrigerant flows into the fifth stage 221e from the bottom of the upwind row 2211 of the two-row heat exchanger 221. The refrigerant flows upward from the fifth stage 221e to the uppermost stage 221b. The flow path branches into two flow paths at the uppermost stage 221b. In one flow path, the refrigerant flows from the uppermost stage 221b of the leeward row 2211 to the tenth stage 221f from the top of the leeward row 2212 and flows upward to the uppermost stage 221c, where the rear-side single-row heat exchanger 222 Of the uppermost stage 222a, and the fourth stage 222c from the top as an outlet. The other flow path flows from the uppermost stage 221b of the leeward row 2211 to the sixth stage 221g from the bottom of the leeward column 2212, passes through the stage 221g one stage below, and passes through the fourth stage from the bottom of the leeward column 2211. Flows downward from the lower stage 221i to the lowermost stage 221a, flows into the lowermost stage 222b of the rear-side single-row heat exchanger 222, and has the fourth stage 222d from the bottom as an outlet.

  As described in the second embodiment, even in the two-pass configuration, the refrigerant flows first through the two-row heat exchanger 221 and then flows through the rear-side single-row heat exchanger 222 in this manner. The difference in the temperature of the air that has passed through the heat exchanger 210 can be reduced. Further, in the present embodiment, all the outlets of each path are provided in the rear-side single-row heat exchanger 222. If one path outlet is provided in the back-side single-row heat exchanger 222 and the other path outlet is provided in the two-row heat exchanger 221, the outlet-side refrigerant whose temperature has decreased is discharged into the two-row heat exchanger 221. And the air may be excessively cooled. In order to avoid such overcooling, in the present embodiment, the outlet of each path is provided in the back-side single-row heat exchanger 222 as described above.

Reference Signs List 10 air conditioner 100 indoor unit 110 heat exchanger 111 double row heat exchanger 112 front side single row heat exchanger 113 rear side single row heat exchanger

Claims (17)

An air conditioner including an indoor unit and an outdoor unit,
The indoor unit has an indoor heat exchanger,
The outdoor unit has an expansion valve,
The indoor heat exchanger has a two-row heat exchanger in which two rows of heat transfer tubes are arranged, and a single-row heat exchanger in which one row of heat transfer tubes is arranged,
The two-row heat exchanger is arranged on the front side of the indoor unit,
The single-row heat exchanger is disposed on the rear side of the indoor unit,
During the cooling operation, the expansion valve is connected to the one-row heat exchanger via at least a part of one row of the two-row heat exchanger and at least a part of the other row of the two-row heat exchanger. Connected to
The air conditioner according to claim 1, wherein a flow path of the indoor heat exchanger is formed in one pass. An air conditioner including an indoor unit and an outdoor unit,
The indoor unit has an indoor heat exchanger,
The outdoor unit has an expansion valve,
The indoor heat exchanger has a two-row heat exchanger in which two rows of heat transfer tubes are arranged, and a single-row heat exchanger in which one row of heat transfer tubes is arranged,
The two-row heat exchanger is arranged on the front side of the indoor unit,
The indoor heat exchanger has a first single-row heat exchanger and a second single-row heat exchanger,
The first single-row heat exchanger is disposed on a rear side of the indoor unit,
The second single-row heat exchanger is disposed below the double-row heat exchanger;
During the cooling operation, the expansion valve is connected to the one-row heat exchanger via at least a part of one row of the two-row heat exchanger and at least a part of the other row of the two-row heat exchanger. Connected to
The air conditioner according to claim 1, wherein a flow path of the indoor heat exchanger is formed in one pass.   The air conditioner according to claim 1, wherein the expansion valve is connected to at least a part of the other row through the entirety of the one row.   The air conditioner according to any one of claims 1 to 3, wherein the expansion valve is connected to the single-row heat exchanger via all flow paths in the double-row heat exchanger. Machine.   2. The double-row heat exchanger is piped such that a temperature of a connecting portion between the single-row heat exchanger and the double-row heat exchanger becomes a temperature determined according to a dew point temperature. 3. The air conditioner according to any one of claims 4 to 4.   The expansion valve is connected to the single-row heat exchanger via at least half of all the flow paths of the double-row heat exchanger in the double-row heat exchanger. The air conditioner according to any one of claims 1 to 5, wherein   The said two-row heat exchanger is connected to the heat exchanger tube provided in the position closest to the said two-row heat exchanger among the said one-row heat exchangers, The Claim 1 characterized by the above-mentioned. Item 2. The air conditioner according to item 1.   The air conditioner according to any one of claims 1 to 7, wherein the one row of the two-row heat exchanger is piped from the expansion valve side along a direction opposite to a direction of gravity. Machine. The one row is arranged on the windward side of the wind flowing into the two-row heat exchanger,
The air conditioner according to any one of claims 1 to 8, wherein the other row is arranged on a leeward side of wind flowing into the two-row heat exchanger.   The air conditioner according to any one of claims 1 to 9, wherein an outlet during the cooling operation of the indoor heat exchanger is provided in the single-row heat exchanger.   The air conditioner according to any one of claims 1 to 10, wherein the heat transfer tube of the indoor heat exchanger is formed of aluminum or an aluminum alloy. An air conditioner including an indoor unit and an outdoor unit,
The indoor unit has an indoor heat exchanger,
The outdoor unit has an expansion valve,
The indoor heat exchanger has a two-row heat exchanger in which two rows of heat transfer tubes are arranged, and a single-row heat exchanger in which one row of heat transfer tubes is arranged,
The two-row heat exchanger is arranged on the front side of the indoor unit,
The single-row heat exchanger is disposed on the rear side of the indoor unit,
During a cooling operation, the expansion valve is connected to the single-row heat exchanger via at least a part of the double-row heat exchanger,
The double-row heat exchanger is piped such that the temperature of the connection between the single-row heat exchanger and the double-row heat exchanger is a temperature determined according to the dew point temperature,
The air conditioner according to claim 1, wherein a flow path of the indoor heat exchanger is formed in one pass. An air conditioner including an indoor unit and an outdoor unit,
The indoor unit has an indoor heat exchanger,
The outdoor unit has an expansion valve,
The indoor heat exchanger includes a two-row heat exchanger in which two rows of heat transfer tubes are arranged, a first single-row heat exchanger in which one row of heat exchanger tubes is arranged, and a one-row heat exchanger tube. A second single-row heat exchanger;
The two-row heat exchanger is arranged on the front side of the indoor unit,
The first single-row heat exchanger is disposed below the double-row heat exchanger;
The second single-row heat exchanger is disposed on a rear side of the indoor unit,
During cooling operation, the expansion valve is connected to the first single-row heat exchanger and the second single-row heat exchanger via at least a part of the double-row heat exchanger ,
The two rows heat exchanger is a pipe such that the temperature of the connecting portion before Symbol the two rows heat exchanger first 1 column heat exchanger is determined temperature depending on the dew point temperature,
The air conditioner according to claim 1, wherein a flow path of the indoor heat exchanger is formed in one pass. An air conditioner including an indoor unit and an outdoor unit,
The indoor unit has an indoor heat exchanger,
The indoor heat exchanger has a two-row heat exchanger in which two rows of heat transfer tubes are arranged, and a single-row heat exchanger in which one row of heat transfer tubes is arranged,
The two-row heat exchanger is arranged on the front side of the indoor unit,
The single-row heat exchanger is disposed on the rear side of the indoor unit,
The outdoor unit has an expansion valve,
During the cooling operation, the expansion valve is connected to the single-row heat exchanger via half or more of all the flow paths of the double-row heat exchanger in the double-row heat exchanger,
The air conditioner according to claim 1, wherein a flow path of the indoor heat exchanger is formed in one pass. An air conditioner including an indoor unit and an outdoor unit,
The indoor unit has an indoor heat exchanger,
The indoor heat exchanger includes a two-row heat exchanger in which two rows of heat transfer tubes are arranged, a first single-row heat exchanger in which one row of heat exchanger tubes is arranged, and a one-row heat exchanger tube. A second single-row heat exchanger,
The two-row heat exchanger is arranged on the front side of the indoor unit,
The first single-row heat exchanger is disposed below the double-row heat exchanger;
The second single-row heat exchanger is disposed on a rear side of the indoor unit,
The outdoor unit has an expansion valve,
At the time of cooling operation, the expansion valve is connected to the first single-row heat exchanger and the first single-row heat exchanger through half or more of all the flow paths of the double-row heat exchanger in the double-row heat exchanger. Connected to a second single-row heat exchanger ,
The air conditioner according to claim 1, wherein a flow path of the indoor heat exchanger is formed in one pass. An air conditioner including an indoor unit and an outdoor unit,
The indoor unit has an indoor heat exchanger,
The outdoor unit has an expansion valve,
The indoor heat exchanger includes an m-row heat exchanger in which m (m is an integer of 2 or more) rows of heat transfer tubes and an n-row (n is an integer of 1 or more and less than m) rows of heat transfer tubes. N-row heat exchanger,
The m-row heat exchanger is disposed on the front side of the indoor unit,
The n-row heat exchanger is disposed on the rear side of the indoor unit,
During the cooling operation, the expansion valve is connected to the n-row heat exchanger via at least a part of the first row of the m-row heat exchanger and at least a part of the second row of the m-row heat exchanger. Connected
The air conditioner according to claim 1, wherein a flow path of the indoor heat exchanger is formed in one pass. An air conditioner including an indoor unit and an outdoor unit,
The indoor unit has an indoor heat exchanger,
The outdoor unit has an expansion valve,
The indoor heat exchanger includes an m-row heat exchanger in which m (m is an integer of 2 or more) rows of heat transfer tubes and an n-row (n is an integer of 1 or more and less than m) rows of heat transfer tubes. A first n-row heat exchanger, and a second n-row heat exchanger in which n-row heat transfer tubes are arranged,
The m-row heat exchanger is disposed on the front side of the indoor unit,
The first n-row heat exchanger is disposed below the m-row heat exchanger;
The second n-row heat exchanger is disposed on the rear side of the indoor unit,
During the cooling operation, the expansion valve, at least a portion of the first column of m column heat exchanger, and through at least a portion of the second column of the m columns heat exchanger, the first n columns fever An exchanger and said second n-row heat exchanger ;
The air conditioner according to claim 1, wherein a flow path of the indoor heat exchanger is formed in one pass.

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