JP2019011941A - Heat exchanger - Google Patents

Abstract

To shorten a time required for melting frost adhering to a bottom heat exchange part in defrosting operation in a case where a heat exchanger is employed in an air conditioner where heating operation and defrosting operation are performed separately, wherein the heat exchanger comprises: a plurality of flat tubes arrayed vertically and formed with a refrigerant passage therein; and a plurality of fins configured to section a clearance between adjacent flat tubes into a plurality of ventilation flues where air flows.SOLUTION: Flat tube (63) constituting a heat exchanger (11) are sectioned into a plurality of heat exchange parts (60A-60G). Each heat exchange part (60A-60G) comprises a main heat exchange part (61A-61G), and a sub heat exchange part (62A-62G) connected to the main heat exchange part (61A-61G) in series at different vertical positions. The first heat exchange part (60A) containing the bottom flat tube (63A) is arranged so that the first main heat exchange part (61A) contains the bottom flat tube (63A).SELECTED DRAWING: Figure 6

Description

  The present invention relates to a heat exchanger, in particular, a plurality of flat tubes arranged vertically and having a refrigerant passage formed therein, and a plurality of air passages partitioned into air between adjacent flat tubes. And a heat exchanger having fins.

  Conventionally, as a heat exchanger housed in an outdoor unit (heat exchange unit) of an air conditioner, a plurality of flat tubes arranged vertically and a plurality of ventilation paths through which air flows between adjacent flat tubes In some cases, a heat exchanger having a plurality of fins is employed. And as such a heat exchanger, as shown, for example in patent documents 1 (Unexamined-Japanese-Patent No. 2012-163313), a plurality of flat tubes are divided into a plurality of heat exchanging parts arranged up and down, Some heat exchange parts are formed to have a main heat exchange part and a sub heat exchange part connected in series to the main heat exchange part below the main heat exchange part.

  The conventional heat exchanger may be employed in an air conditioner that switches between heating operation and defrosting operation. Here, when the air conditioner performs the heating operation, the conventional heat exchanger is used as an evaporator of the refrigerant, and when the air conditioner performs the defrosting operation, the conventional heat exchanger is Used as a refrigerant radiator. Specifically, when the conventional heat exchanger is used as a refrigerant evaporator, the refrigerant in a gas-liquid two-phase state branches and flows into the sub heat exchange units constituting each heat exchange unit, The refrigerant in the gas-liquid two-phase state that has flowed into the sub heat exchange section passes through the sub heat exchange section and the main heat exchange section in this order and is heated, and flows out from each heat exchange section to join. When the conventional heat exchanger is used as a refrigerant radiator, the gas refrigerant branches and flows into the main heat exchange section of each heat exchange section, and flows into the main heat exchange section. The refrigerant in the state passes through the main heat exchange unit and the sub heat exchange unit in order and is cooled, and flows out from each heat exchange unit and joins.

  However, in the air conditioner employing the above-described conventional heat exchanger, the time required for melting the frost adhering to the heat exchanging portion constituting the lowermost heat exchanging portion during the defrosting operation is lower than the lowermost step. It tends to be longer than the time required to melt the frost attached to the heat exchange part on the upper stage side than the heat exchange part. For this reason, even after the defrosting operation, frost melting residue may occur in the lowermost heat exchanging part and the defrosting may be insufficient, and frost remaining unmelted in the lowermost heat exchanging part may occur. In order to suppress this, it is necessary to lengthen the time of the defrosting operation.

  An object of the present invention is to provide a plurality of flat tubes arranged vertically and having a refrigerant passage formed therein, and a plurality of fins partitioned into a plurality of ventilation paths through which air flows between adjacent flat tubes. When the heat exchanger is used in an air conditioner that switches between heating operation and defrosting operation, the time required to melt the frost adhering to the lowermost heat exchange part during the defrosting operation is To shorten it.

  The heat exchanger according to the first aspect includes a plurality of flat tubes arranged vertically and having a refrigerant passage formed therein, and a plurality of air passages that partition between adjacent flat tubes into a plurality of ventilation paths. And fins. The flat tube is divided into a plurality of heat exchanging parts, and each heat exchanging part is a main heat exchanging part and a sub heat exchanging part connected in series to the main heat exchanging part at a different vertical position from the main heat exchanging part. And have. And here, let the heat exchange part containing the lowest flat tube among heat exchange parts be the 1st heat exchange part, and the main heat exchange part and sub heat exchange part which constitute the 1st heat exchange part are the 1st main heat exchange. If it is set as an exchange part and a 1st sub heat exchange part, the 1st main heat exchange part is arrange | positioned so that the lowermost flat tube may be included.

  First, when the conventional heat exchanger is used in an air conditioner that switches between heating operation and defrosting operation, it is necessary to melt the frost adhering to the lowest heat exchange part during the defrosting operation. The reason why the long time is likely to be longer than the time required to melt the frost attached to the heat exchange part on the upper stage side than the heat exchange part on the lowermost stage will be described.

  In the conventional heat exchanger, a plurality of flat tubes are divided into a plurality of heat exchanging portions arranged in the vertical direction, and each heat exchanging portion has a main heat exchanging portion below the main heat exchanging portion and the main heat exchanging portion. And a sub heat exchange section connected in series to the section. For this reason, in the said conventional heat exchanger, the sub heat exchange part which comprises the lowest heat exchange part among heat exchange parts is arrange | positioned so that a flat tube of the lowest stage may be included.

  In this conventional configuration, when switching from heating operation (used as a refrigerant evaporator) to defrosting operation (used as a refrigerant radiator), a liquid state is placed in the lowermost sub heat exchange section including the lowermost flat tube. The refrigerant is easy to accumulate. Then, when the defrosting operation is performed in such a state, the refrigerant in the gas state first flows into the lowermost main heat exchange part, and then flows into the lowermost sub heat exchange part. It takes time to evaporate the liquid refrigerant accumulated in the sub heat exchange section. That is, in the configuration of the conventional heat exchanger, the lowermost sub heat exchange part including the lowermost flat tube during the defrosting operation is located on the downstream side of the refrigerant flow. It is presumed that this is one of the causes that the time required to melt the frost adhering to the heat exchange part becomes long.

  In addition, in this configuration, when the refrigerant in the gas state branches during the defrosting operation and flows into the main heat exchange part of each heat exchange part, the refrigerant is affected by the liquid head of the refrigerant and the heat exchange part on the upper stage side. In comparison, the flow rate of the refrigerant in the gas state flowing into the lowermost heat exchanging portion is reduced, and the time required for melting the frost attached to the lowermost heat exchanging portion is lengthened. Since the degree of the liquid head is affected by the height position of the flat tube included in the sub heat exchange unit constituting the heat exchange unit, the lowermost sub heat exchange unit includes the lowermost flat tube. And the liquid head of a refrigerant | coolant is large and the flow volume of the refrigerant | coolant of the gas state which flows in at the time of a defrost operation further decreases. That is, in the configuration of the conventional heat exchanger described above, the flow rate of the refrigerant in the gas state flowing into the lowermost heat exchanging section by the refrigerant liquid head during the defrosting operation is reduced, so that the lowermost heat exchange is performed during the defrosting operation. It is estimated that this is one of the causes that the time required to melt the frost attached to the part becomes longer.

  Further, in this conventional configuration, since the lower end portion of the fin close to the lowermost flat tube is in contact with the drain pan, heat is easily generated from the lowermost sub heat exchange portion including the lowermost flat tube to the drain pan. . And, when the defrosting operation is performed in such a state, the heat in the lowermost heat exchanging portion is less likely to rise than the upper heat exchanging portion due to heat radiation from the lowermost sub heat exchanging portion to the drain pan. The time required to melt the frost adhering to the lowermost heat exchanging portion is lengthened. That is, in the configuration of the conventional heat exchanger described above, the heat radiation from the lowermost sub heat exchange part including the lowermost flat tube to the drain pan melts the frost attached to the lowermost heat exchange part during the defrosting operation. It is presumed that this is one of the causes of the long time required for this.

  As described above, the conventional heat exchanger is employed in an air conditioner that switches between heating operation and defrosting operation because the lowermost sub heat exchange section includes the lowermost flat tube. In this case, the time required to melt the frost attached to the lowermost heat exchange part is longer than the time required to melt the frost attached to the upper heat exchange part than the lowermost heat exchange part. Is also estimated to be longer.

  Therefore, here, unlike the conventional heat exchanger, as described above, the first main heat exchanging part constituting the first heat exchanging part including the lowermost flat tube among the heat exchanging parts is the lowermost stage. It arrange | positions so that a flat tube may be included.

  And when the heat exchanger which has this structure is employ | adopted for the air conditioning apparatus which switches heating operation and defrost operation, when it pays attention to a 1st heat exchange part, heating operation (uses it as an evaporator of a refrigerant | coolant). Sometimes the gas-liquid two-phase refrigerant flows into the first sub heat exchange section, and the gas-liquid two-phase refrigerant flowing into the first sub heat exchange section is the first sub heat exchange section, the lowermost flat tube The first main heat exchanging part including the heat is passed through and heated and flows out of the first heat exchanging part. Further, during the defrosting operation (used as a refrigerant radiator), the gaseous refrigerant flows into the first main heat exchange section, and the gaseous refrigerant flowing into the first main heat exchange section is the lowermost flat tube. The first main heat exchange part including the first heat exchange part and the first sub heat exchange part are passed through in order to be cooled and flow out of the first heat exchange part. That is, here, at the time of the defrosting operation, the first main heat exchange unit including the lowermost flat tube is positioned on the upstream side of the refrigerant flow. Therefore, here, the refrigerant in the gas state is caused to flow into the first main heat exchange section including the lowermost flat tube, and the liquid refrigerant accumulated in the first sub heat exchange section at the lowermost stage is actively heated. As well as evaporating, it becomes possible to quickly increase the temperature in the first heat exchange section at the lowermost stage, which makes it possible to reduce the temperature at the lowermost stage during the defrosting operation as compared with the case where the conventional heat exchanger is employed. The time required to melt the frost adhering to the heat exchange part can be shortened.

  Thus, here, by adopting the heat exchanger having the above-described configuration in an air conditioner that switches between heating operation and defrosting operation, frost adhering to the lowermost heat exchange section during the defrosting operation The time required to melt the can be shortened.

  In the heat exchanger according to the second aspect, in the heat exchanger according to the first aspect, all the heat exchange parts other than the first heat exchange part are arranged above the first heat exchange part. And the 1st main heat exchange part is arrange | positioned under the 1st sub heat exchange part at the 1st heat exchange part.

  When the heat exchanger having this configuration is employed in an air conditioner that switches between heating operation and defrosting operation, paying attention to the first heat exchange unit, during heating operation (used as a refrigerant evaporator), The gas-liquid two-phase refrigerant flows into the first sub heat exchange unit, and the gas-liquid two-phase refrigerant that flows into the first sub heat exchange unit flows into the first sub heat exchange unit and the first sub heat exchange unit. The first main heat exchanging part located below is passed through and heated, and flows out of the first heat exchanging part. Further, during the defrosting operation (used as a refrigerant radiator), the gaseous refrigerant flows into the first main heat exchange unit, and the gaseous refrigerant that has flowed into the first main heat exchange unit undergoes the first main heat exchange. And the first sub heat exchanging part located above the first main heat exchanging part are cooled in this order and flow out of the first heat exchanging part.

  The heat exchanger according to the third aspect is the heat exchanger according to the second aspect, wherein the number of flat tubes constituting the first main heat exchange unit is equal to the number of flat tubes constituting the first sub heat exchange unit. The ratio is set to be smaller than the ratio of the number of flat tubes constituting the main heat exchange unit to the number of flat tubes constituting the sub heat exchange unit in the other heat exchange unit.

  As described above, the heat exchanger according to the second aspect includes the first heat exchange part in which the first main heat exchange part is disposed below the first sub heat exchange part. For this reason, when the heat exchanger according to the second aspect is employed in an air conditioner that switches between heating operation and defrosting operation, the first heat is generated during the heating operation (used as a refrigerant evaporator). The exchange unit functions as a so-called downflow type evaporator in which the refrigerant passes through the first main heat exchange unit disposed below the first sub heat exchange unit after passing through the first sub heat exchange unit. Become. Here, in a downflow type evaporator, when a fluid in a gas-liquid two-phase state is sent downward and accompanied by a fluid diversion, fluid drift tends to occur. For this reason, also in the 1st heat exchanging part, when a refrigerant is sent from the flat tube which constitutes the 1st sub heat exchanging part to the flat tube which constitutes the 1st main heat exchanging part downward, it is accompanied by a branch of refrigerant. There is a risk of refrigerant drift. At this time, if the ratio of the number of flat tubes constituting the first main heat exchange portion to the number of flat tubes constituting the first sub heat exchange portion is increased, the risk of refrigerant drift increases.

  Therefore, here, as described above, for the first heat exchange part, the ratio of the number of flat tubes constituting the main heat exchange part to the number of flat pipes constituting the sub heat exchange part is determined as another heat exchange part. It is set to be smaller.

  Thereby, here, at the time of heating operation (used as an evaporator of the refrigerant), when the refrigerant is sent downward from the flat tube constituting the first sub heat exchange unit to the flat tube constituting the first main heat exchange unit In addition, it is possible to suppress the refrigerant drift due to the refrigerant split.

  In the heat exchanger according to the fourth aspect, in the heat exchanger according to the first aspect, all the heat exchange parts other than the first heat exchange part are arranged above the first heat exchange part. The first sub heat exchange section includes a first upper sub heat exchange section and a first lower sub heat exchange section below the first upper sub heat exchange section. In addition, the first main heat exchanging unit includes a first upper main heat exchanging unit connected to the first upper sub heat exchanging unit above the first upper sub heat exchanging unit and a lower portion of the first lower sub heat exchanging unit. And a first lower main heat exchange section connected to the first lower sub heat exchange section.

  When the heat exchanger having this configuration is employed in an air conditioner that switches between heating operation and defrosting operation, paying attention to the first heat exchange unit, during heating operation (used as a refrigerant evaporator), The gas-liquid two-phase refrigerant flows into the first upper sub heat exchange unit and the first lower sub heat exchange unit. The refrigerant in the gas-liquid two-phase state that has flowed into the first upper sub heat exchange section is in the order of the first upper sub heat exchange section and the first upper main heat exchange section located above the first upper sub heat exchange section. It passes through and is heated and flows out of the first heat exchange section. The refrigerant in the gas-liquid two-phase state that has flowed into the first lower sub heat exchange unit is a first lower main heat exchange unit located below the first lower sub heat exchange unit and the first lower sub heat exchange unit. Are passed through in this order and heated to flow out of the first heat exchange section. Further, during the defrosting operation (used as a refrigerant radiator), the gaseous refrigerant flows into the first upper main heat exchange unit and the first lower main heat exchange unit. The gas refrigerant flowing into the first upper main heat exchange section passes through the first upper main heat exchange section and the first upper sub heat exchange section located below the first upper main heat exchange section in this order. It is cooled and flows out of the first heat exchange part. The refrigerant in the gas state that has flowed into the first lower main heat exchange section passes through the first lower main heat exchange section and the first lower sub heat exchange section located above the first lower main heat exchange section in this order. Then, it is cooled and flows out of the first heat exchange section.

  A heat exchanger according to a fifth aspect is the heat exchanger according to the fourth aspect, wherein the flats constituting the first lower main heat exchange part with respect to the number of flat tubes constituting the first lower sub heat exchange part are provided. The ratio of the number of tubes is set to be smaller than the ratio of the number of flat tubes constituting the first upper main heat exchange unit to the number of flat tubes constituting the first upper sub heat exchange unit.

  In the heat exchanger according to the fourth aspect, as described above, the first upper sub heat exchange unit is disposed below the first upper main heat exchange unit, and the first lower sub heat exchange unit is below. 1st lower main heat exchange part has the 1st heat exchange part arranged. For this reason, when the heat exchanger according to the fourth aspect is employed in an air conditioner that switches between heating operation and defrosting operation, the first heat is generated during the heating operation (used as a refrigerant evaporator). The first lower sub heat exchange part and the first lower main heat exchange part among the exchange parts are disposed below the first lower sub heat exchange part after the refrigerant passes through the first lower sub heat exchange part. In addition, it functions as a so-called downflow type evaporator that passes through the first lower main heat exchange section. Here, in a downflow type evaporator, when a fluid in a gas-liquid two-phase state is sent downward and accompanied by a fluid diversion, fluid drift tends to occur. Therefore, also in the first lower sub heat exchange section and the first lower main heat exchange section, the flat pipe constituting the first lower main heat exchange section from the flat pipe constituting the first lower sub heat exchange section. When the refrigerant is sent downward, the refrigerant is diverted, and there is a possibility that the refrigerant drifts. At this time, if the ratio of the number of flat tubes constituting the first lower main heat exchange portion to the number of flat tubes constituting the first lower sub heat exchange portion is increased, there is a high risk of refrigerant drift. .

  Therefore, here, as described above, for the first heat exchange part, the number of flat tubes constituting the first lower main heat exchange part with respect to the number of flat pipes constituting the first lower sub heat exchange part. The ratio is set to be smaller than the ratio of the number of flat tubes constituting the first upper main heat exchange portion to the number of flat tubes constituting the first upper sub heat exchange portion.

  Thereby, here, at the time of heating operation (used as an evaporator of the refrigerant), the refrigerant is moved downward from the flat tube constituting the first lower sub heat exchange portion to the flat tube constituting the first lower main heat exchange portion. When sending the refrigerant, it is possible to suppress the drift of the refrigerant accompanying the flow of the refrigerant.

  A heat exchanger according to a sixth aspect is the heat exchanger according to any one of the first to fifth aspects, wherein the heat exchange units are arranged side by side, and heat other than the first heat exchange unit The sub heat exchange part is arrange | positioned under the main heat exchange part at the exchange part.

  When the heat exchanger having this configuration is adopted in an air conditioner that performs switching between heating operation and defrosting operation, when attention is paid to the heat exchange unit other than the first heat exchange unit, the heating operation (refrigerant evaporator) The gas-liquid two-phase refrigerant flows into the sub heat exchange section, and the gas-liquid two-phase refrigerant flowing into the sub heat exchange section is located above the sub heat exchange section and the sub heat exchange section. The main heat exchanging parts that pass through are heated by passing through the heat exchanging parts. In addition, during the defrosting operation (used as a radiator radiator), the gaseous refrigerant flows into the main heat exchange unit, and the gaseous refrigerant that flows into the main heat exchange unit includes the main heat exchange unit and the main heat exchange unit. It passes through the sub heat exchanging part located in the lower part in order, is cooled, and flows out of the heat exchanging part.

  As described in the above description, according to the present invention, the first main heat exchanging portion constituting the first heat exchanging portion including the lowermost flat tube is arranged to include the lowermost flat tube. By adopting a heat exchanger with an air conditioner that switches between heating operation and defrosting operation, the time required to melt the frost adhering to the lowest heat exchange part during the defrosting operation is shortened be able to.

It is a schematic block diagram of the air conditioning apparatus by which the outdoor heat exchanger as a heat exchanger concerning one Embodiment of this invention was employ | adopted. It is an external appearance perspective view of an outdoor unit. It is a front view of an outdoor unit (shown excluding refrigerant circuit components other than the outdoor heat exchanger). It is a schematic perspective view of an outdoor heat exchanger. It is a partial expansion perspective view of the heat exchange part of FIG. It is a schematic block diagram of an outdoor heat exchanger. It is the figure which tabulated schematic structure of the outdoor heat exchanger. FIG. 7 is an enlarged view of the vicinity of the lowermost heat exchange section (first heat exchange section) in FIG. 6 (the refrigerant flow during heating operation is illustrated). FIG. 7 is an enlarged view of the lowermost heat exchange section (first heat exchange section) in FIG. 6 (the refrigerant flow during the defrosting operation is illustrated). It is a schematic perspective view of the outdoor heat exchanger as a heat exchanger concerning a modification. It is a schematic block diagram of the outdoor heat exchanger concerning a modification. It is the figure which tabulated schematic structure of the outdoor heat exchanger concerning a modification. FIG. 12 is an enlarged view of the vicinity of the lowermost heat exchange section (first heat exchange section) in FIG. 11 (the refrigerant flow during heating operation is illustrated). FIG. 12 is an enlarged view of the vicinity of the lowermost heat exchange section (first heat exchange section) in FIG. 11 (the refrigerant flow during the defrosting operation is illustrated).

  Hereinafter, an embodiment of a heat exchanger concerning the present invention and its modification are described based on a drawing. In addition, the specific structure of the heat exchanger concerning this invention is not restricted to the following embodiment and its modification, It can change in the range which does not deviate from the summary of invention.

(1) Configuration of Air Conditioner FIG. 1 is a schematic configuration diagram of an air conditioner 1 in which an outdoor heat exchanger 11 as a heat exchanger according to an embodiment of the present invention is employed.

  The air conditioner 1 is a device capable of cooling and heating a room such as a building by performing a vapor compression refrigeration cycle. The air conditioner 1 mainly includes an outdoor unit 2, indoor units 3a and 3b, a liquid refrigerant communication tube 4 and a gas refrigerant communication tube 5 that connect the outdoor unit 2 and the indoor units 3a and 3b, an outdoor unit 2 and And a control unit 23 that controls the constituent devices of the indoor units 3a and 3b. The vapor compression refrigerant circuit 6 of the air conditioner 1 is configured by connecting the outdoor unit 2 and the indoor units 3 a and 3 b via the refrigerant communication tubes 4 and 5.

  The outdoor unit 2 is installed outdoors (on the roof of a building, in the vicinity of the wall surface of the building, etc.) and constitutes a part of the refrigerant circuit 6. The outdoor unit 2 mainly includes an accumulator 7, a compressor 8, a four-way switching valve 10, an outdoor heat exchanger 11, an outdoor expansion valve 12 as an expansion mechanism, a liquid side shut-off valve 13, and a gas side shut-off valve. 14 and an outdoor fan 15. Each device and the valve are connected by refrigerant pipes 16 to 22.

  The indoor units 3 a and 3 b are installed indoors (such as a living room or a ceiling space) and constitute a part of the refrigerant circuit 6. The indoor unit 3a mainly has an indoor expansion valve 31a, an indoor heat exchanger 32a, and an indoor fan 33a. The indoor unit 3b mainly includes an indoor expansion valve 31b as an expansion mechanism, an indoor heat exchanger 32b, and an indoor fan 33b.

  The refrigerant communication pipes 4 and 5 are refrigerant pipes that are constructed on site when the air conditioner 1 is installed at an installation location such as a building. One end of the liquid refrigerant communication tube 4 is connected to the liquid side closing valve 13 of the indoor unit 2, and the other end of the liquid refrigerant communication tube 4 is connected to the liquid side ends of the indoor expansion valves 31a and 31b of the indoor units 3a and 3b. Has been. One end of the gas refrigerant communication pipe 5 is connected to the gas side shut-off valve 14 of the indoor unit 2, and the other end of the gas refrigerant communication pipe 5 is connected to the gas side ends of the indoor heat exchangers 32a and 32b of the indoor units 3a and 3b. It is connected.

  The control unit 23 is configured by communication connection of control boards and the like (not shown) provided in the outdoor unit 2 and the indoor units 3a and 3b. In FIG. 1, for the sake of convenience, the outdoor unit 2 and the indoor units 3a and 3b are illustrated at positions away from each other. The control unit 23 controls the components 8, 10, 12, 15, 31a, 31b, 33a, 33b of the air conditioner 1 (here, the outdoor unit 2 and the indoor units 3a, 3b), that is, the air conditioner 1 The whole operation control is performed.

(2) Operation | movement of an air conditioning apparatus Next, operation | movement of the air conditioning apparatus 1 is demonstrated using FIG. In the air conditioner 1, the cooling operation in which the refrigerant is circulated in the order of the compressor 8, the outdoor heat exchanger 11, the outdoor expansion valve 12, the indoor expansion valves 31a and 31b, and the indoor heat exchangers 32a and 32b, the compressor 8, the indoor Heating operation is performed in which the refrigerant is circulated in the order of the heat exchangers 32a and 32b, the indoor expansion valves 31a and 31b, the outdoor expansion valve 12, and the outdoor heat exchanger 11. Moreover, at the time of heating operation, the defrost operation for melting the frost adhering to the outdoor heat exchanger 11 is performed. Here, similarly to the cooling operation, the reverse cycle defrosting operation in which the refrigerant is circulated in the order of the compressor 8, the outdoor heat exchanger 11, the outdoor expansion valve 12, the indoor expansion valves 31a and 31b, and the indoor heat exchangers 32a and 32b. Is done. The cooling operation, the heating operation, and the defrosting operation are performed by the control unit 23.

  During the cooling operation, the four-way switching valve 10 is switched to the outdoor heat dissipation state (the state shown by the solid line in FIG. 1). In the refrigerant circuit 6, the low-pressure gas refrigerant in the refrigeration cycle is sucked into the compressor 8 and is compressed until it reaches the high pressure in the refrigeration cycle, and then discharged. The high-pressure gas refrigerant discharged from the compressor 8 is sent to the outdoor heat exchanger 11 through the four-way switching valve 10. The high-pressure gas refrigerant sent to the outdoor heat exchanger 11 dissipates heat by exchanging heat with outdoor air supplied as a cooling source by the outdoor fan 15 in the outdoor heat exchanger 11 that functions as a refrigerant radiator. Become a high-pressure liquid refrigerant. The high-pressure liquid refrigerant radiated in the outdoor heat exchanger 11 is sent to the indoor expansion valves 31 a and 31 b through the outdoor expansion valve 12, the liquid-side closing valve 13, and the liquid refrigerant communication pipe 4. The refrigerant sent to the indoor expansion valves 31a and 31b is decompressed to the low pressure of the refrigeration cycle by the indoor expansion valves 31a and 31b, and becomes a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant decompressed by the indoor expansion valves 31a and 31b is sent to the indoor heat exchangers 32a and 32b. The low-pressure gas-liquid two-phase refrigerant sent to the indoor heat exchangers 32a and 32b exchanges heat with indoor air supplied as a heating source by the indoor fans 33a and 33b in the indoor heat exchangers 32a and 32b. Evaporate. As a result, the room air is cooled and then supplied to the room to cool the room. The low-pressure gas refrigerant evaporated in the indoor heat exchangers 32 a and 32 b is again sucked into the compressor 8 through the gas refrigerant communication pipe 5, the gas side closing valve 14, the four-way switching valve 10, and the accumulator 7.

  During the heating operation, the four-way selector valve 10 is switched to the outdoor evaporation state (the state indicated by the broken line in FIG. 1). In the refrigerant circuit 6, the low-pressure gas refrigerant in the refrigeration cycle is sucked into the compressor 8 and is compressed until it reaches the high pressure in the refrigeration cycle, and then discharged. The high-pressure gas refrigerant discharged from the compressor 8 is sent to the indoor heat exchangers 32 a and 32 b through the four-way switching valve 10, the gas side closing valve 14, and the gas refrigerant communication pipe 5. The high-pressure gas refrigerant sent to the indoor heat exchangers 32a and 32b dissipates heat by exchanging heat with indoor air supplied as a cooling source by the indoor fans 33a and 33b in the indoor heat exchangers 32a and 32b. Becomes a high-pressure liquid refrigerant. Thereby, indoor air is heated, and indoor heating is performed by being supplied indoors after that. The high-pressure liquid refrigerant radiated by the indoor heat exchangers 32 a and 32 b is sent to the outdoor expansion valve 12 through the indoor expansion valves 31 a and 31 b, the liquid refrigerant communication tube 4 and the liquid-side closing valve 13. The refrigerant sent to the outdoor expansion valve 12 is decompressed to the low pressure of the refrigeration cycle by the outdoor expansion valve 12, and becomes a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant decompressed by the outdoor expansion valve 12 is sent to the outdoor heat exchanger 11. The low-pressure gas-liquid two-phase refrigerant sent to the outdoor heat exchanger 11 exchanges heat with outdoor air supplied as a heating source by the outdoor fan 15 in the outdoor heat exchanger 11 that functions as a refrigerant evaporator. Go and evaporate into a low-pressure gas refrigerant. The low-pressure refrigerant evaporated in the outdoor heat exchanger 11 is again sucked into the compressor 8 through the four-way switching valve 10 and the accumulator 7.

  During the heating operation described above, when frost formation in the outdoor heat exchanger 11 is detected due to the refrigerant temperature in the outdoor heat exchanger 11 being lower than a predetermined temperature, that is, defrosting of the outdoor heat exchanger 11 is performed. When the conditions to start are reached, a defrosting operation is performed to melt frost attached to the outdoor heat exchanger 11.

  As in the cooling operation, the defrosting operation is performed by switching the four-way switching valve 22 to the outdoor heat radiation state (the state indicated by the solid line in FIG. 1) and causing the outdoor heat exchanger 11 to function as a refrigerant radiator. Is called. Thereby, the frost adhering to the outdoor heat exchanger 11 can be thawed. The defrosting operation is performed outdoors until the defrosting time set in consideration of the state of the heating operation before defrosting, or the temperature of the refrigerant in the outdoor heat exchanger 11 becomes higher than a predetermined temperature. This is performed until it is determined that the defrosting in the heat exchanger 11 is completed, and then the heating operation is resumed. In addition, since the flow of the refrigerant | coolant in the refrigerant circuit 10 at the time of a defrost operation is the same as that of a cooling operation, description is abbreviate | omitted here.

(3) Configuration of Outdoor Unit FIG. 2 is an external perspective view of the outdoor unit 2. FIG. 3 is a front view of the outdoor unit 2 (illustrated excluding refrigerant circuit components other than the outdoor heat exchanger 11). FIG. 4 is a schematic perspective view of the outdoor heat exchanger 11. FIG. 5 is a partially enlarged view of the heat exchange units 60A to 60F in FIG. FIG. 6 is a schematic configuration diagram of the outdoor heat exchanger 11. FIG. 7 is a table listing the schematic configuration of the outdoor heat exchanger 11. FIG. 8 is an enlarged view (the refrigerant flow during heating operation is illustrated) in the vicinity of the lowermost heat exchange section (first heat exchange section 60A) of FIG. FIG. 9 is an enlarged view (the refrigerant flow during the defrosting operation is illustrated) in the vicinity of the lowermost heat exchange section (first heat exchange section 60A) of FIG.

<Overall>
The outdoor unit 2 is a top blow type heat exchange unit that sucks air from the side surface of the casing 40 and blows air from the top surface of the casing 40. The outdoor unit 2 mainly includes a substantially rectangular parallelepiped box-shaped casing 40, an outdoor fan 15 as a blower, devices 7, 8, 11 such as a compressor and an outdoor heat exchanger, a four-way switching valve, an outdoor expansion valve, and the like. And refrigerant circuit components that constitute part of the refrigerant circuit 6 including the valves 10, 12 to 14, the refrigerant pipes 16 to 22, and the like. In the following description, “top”, “bottom”, “left”, “right”, “front”, “back”, “front”, and “back” are shown in FIG. 2 unless otherwise specified. The direction when the outdoor unit 2 to be viewed is viewed from the front (left oblique front side of the drawing) is meant.

  The casing 40 mainly includes a bottom frame 42 that spans a pair of installation legs 41 that extend in the left-right direction, a column 43 that extends vertically from a corner of the bottom frame 42, and a fan module 44 that is attached to the upper end of the column 43. And a front panel 45, and air inlets 40a, 40b, 40c are formed on the side surfaces (here, the rear surface and the left and right side surfaces), and an air outlet 40d is formed on the top surface.

  The bottom frame 42 forms the bottom surface of the casing 40, and the outdoor heat exchanger 11 is provided on the bottom frame 42. Here, the outdoor heat exchanger 11 is a substantially U-shaped heat exchanger in plan view facing the back surface and both left and right side surfaces of the casing 40, and substantially forms the back surface and both left and right side surfaces of the casing 40. . The bottom frame 42 is in contact with the lower end portion of the outdoor heat exchanger 11 and functions as a drain pan that receives drain water generated in the outdoor heat exchanger 11 during cooling operation or defrosting operation.

  A fan module 44 is provided on the upper side of the outdoor heat exchanger 11, and forms a portion above the front and rear surfaces of the casing 40 and the right and left both-side support columns 43 and the top surface of the casing 40. . Here, the fan module 44 is an assembly in which the outdoor fan 15 is accommodated in a substantially rectangular parallelepiped box having an upper surface and a lower surface opened. The opening on the top surface of the fan module 44 is an air outlet 40d, and an air outlet grill 46 is provided at the air outlet 40d. The outdoor fan 15 is disposed in the casing 40 so as to face the air outlet 40d, and is a blower that takes air into the casing 40 from the suction ports 40a, 40b, and 40c and discharges it from the air outlet 40d.

  The front panel 45 is spanned between the support columns 43 on the front side, and forms the front surface of the casing 40.

  In the casing 40, refrigerant circuit components (the accumulator 7 and the compressor 8 are shown in FIG. 2) other than the outdoor fan 15 and the outdoor heat exchanger 11 are also accommodated. Here, the compressor 8 and the accumulator 7 are provided on the bottom frame 42.

  As described above, the outdoor unit 2 includes the casing 40 in which the air suction ports 40a, 40b, and 40c are formed on the side surfaces (here, the rear surface and the left and right side surfaces), and the air outlet 40d is formed on the top surface. It has the outdoor fan 15 arrange | positioned facing the blower outlet 40d in the inside, and the outdoor heat exchanger 11 arrange | positioned in the casing 40 under the outdoor fan 15 inside.

<Outdoor heat exchanger>
The outdoor heat exchanger 11 is a heat exchanger that performs heat exchange between the refrigerant and the outdoor air, and mainly includes a first header collecting pipe 80, a second header collecting pipe 90, a plurality of flat tubes 63, and a plurality of flat tubes 63. And fins 64. Here, all of the first header collecting pipe 80, the second header collecting pipe 90, the flat pipe 63, and the fins 64 are formed of aluminum or an aluminum alloy, and are joined to each other by brazing or the like.

  Each of the first header collecting pipe 80 and the second header collecting pipe 90 is a vertically long hollow cylindrical member with its upper end and lower end closed. The first header collecting pipe 80 is erected on one end side of the outdoor heat exchanger 11 (here, the left front end side in FIG. 4 or the left end side in FIG. 6), and the second header collecting pipe 90 is It is erected on the other end side of the outdoor heat exchanger 11 (here, the right front end side in FIG. 4 or the right end side in FIG. 6).

  The flat tube 63 is a flat multi-hole tube having a flat surface portion 63a facing the vertical direction serving as a heat transfer surface, and a large number of small passages 63b through which a refrigerant formed inside flows. A plurality of flat tubes 63 are arranged vertically, and both ends thereof are connected to the first header collecting tube 80 and the second header collecting tube 90. The fins 64 are partitioned into a plurality of ventilation paths through which air flows between adjacent flat tubes 63, and a plurality of cutouts 64a extending horizontally are formed so that the plurality of flat tubes 63 can be inserted. . The shape of the notch 64 a of the fin 64 substantially matches the outer shape of the cross section of the flat tube 63.

  In the outdoor heat exchanger 11, the plurality of flat tubes 63 are divided into a plurality of (here, six) heat exchange units 60A to 60F arranged vertically. Specifically, here, in order from the bottom to the top, the first heat exchange unit 60A, the second heat exchange unit 60B,..., The fifth heat exchange unit 60E, and the sixth heat, which are the lowest heat exchange units. An exchange part 60F is formed. The first heat exchanging part 60A has 21 flat tubes 63 including a flat tube 63A at the lowest stage. The second heat exchanging unit 60B has 18 flat tubes 63. The third heat exchanging part 60 </ b> C has 15 flat tubes 63. The fourth heat exchanging unit 60D has 13 flat tubes 63. The fifth heat exchanging unit 60E has eleven flat tubes 63. The sixth heat exchanging unit 60F has nine flat tubes 63.

  The first header collecting pipe 80 is partitioned into upper and lower portions by a partition plate 81 to form entrance / exit communication spaces 82A to 82F corresponding to the heat exchange portions 60A to 60F. Further, each of the inlet / outlet communication spaces 82B to 82F excluding the first inlet / outlet communication space 82A corresponding to the first heat exchange section 60A is divided into two upper and lower portions by the partition plate 83, so that the upper gas side inlet / outlet communication space 84B. To 84F and lower liquid side inlet / outlet communication spaces 85B to 85F are formed. The first inlet / outlet communication space 82A corresponding to the first heat exchange section 60A is partitioned into two upper and lower parts by two partition plates 86, so that the first upper gas side inlet / outlet communication space 84AU and A first liquid side inlet / outlet communication space 85A and a first lower gas side inlet / outlet communication space 84AL are formed. Here, the first upper gas side inlet / outlet communication space 84AU and the first lower gas side inlet / outlet communication space 84AL are collectively referred to as a first gas side inlet / outlet communication space 84A.

  The second gas side inlet / outlet communication space 84B communicates with the top twelve of the flat tubes 63 that constitute the second heat exchange section 60B, and the second liquid side inlet / outlet communication space 85B includes the second heat exchange section 60B. The remaining six flat tubes 63 communicate with the remaining flat tubes 63. The third gas side inlet / outlet communication space 84C communicates with the top ten of the flat tubes 63 constituting the third heat exchange part 60C, and the third liquid side inlet / outlet communication space 85C constitutes the third heat exchange part 60C. The remaining five flat tubes 63 communicate with the remaining flat tubes 63. The fourth gas side inlet / outlet communication space 84D communicates with nine of the flat tubes 63 constituting the fourth heat exchange part 60D from above, and the fourth liquid side inlet / outlet communication space 85D constitutes the fourth heat exchange part 60D. The remaining four flat tubes 63 communicate with the remaining flat tubes 63. The fifth gas side inlet / outlet communication space 84E communicates with seven of the flat tubes 63 constituting the fifth heat exchange unit 60E from the top, and the fifth liquid side inlet / outlet communication space 85E constitutes the fifth heat exchange unit 60E. The remaining four flat tubes 63 communicate with the remaining flat tubes 63. The sixth gas side inlet / outlet communication space 84F communicates with the top six of the flat tubes 63 constituting the sixth heat exchange part 60F, and the sixth liquid side inlet / outlet communication space 85F constitutes the sixth heat exchange part 60F. The remaining three flat tubes 63 communicate with the remaining flat tubes 63. The first upper gas side inlet / outlet communication space 84AU communicates with twelve from the top among the flat tubes 63 constituting the first heat exchange section 60A, and the first lower gas side inlet / outlet communication space 84AL is the first heat exchange section. Of the flat tubes 63 constituting 60A, the lower one including the lowest flat tube 63A communicates with the bottom two, and the first liquid side inlet / outlet communication space 85A is the remaining 7 of the flat tubes 63 constituting the first heat exchange section 60A. Communicate with the book.

  Here, the flat tubes 63 communicating with the gas side inlet / outlet communication spaces 84A to 84F are referred to as main heat exchange portions 61A to 61F, and the flat tubes 63 connected to the liquid side inlet / outlet communication spaces 85A to 85F are sub heat exchange portions 62A to 62F. And That is, in the second inlet / outlet communication space 82B, the second gas side inlet / outlet communication space 84B communicates with twelve from the top of the flat tubes 63 constituting the second heat exchange section 60B (second main heat exchange section 61B), The second liquid side inlet / outlet communication space 85B communicates with the remaining six flat tubes 63 of the flat tube 63 constituting the second heat exchange portion 60B (second sub heat exchange portion 62B). In the third inlet / outlet communication space 82C, the third gas-side inlet / outlet communication space 84C communicates with the top ten of the flat tubes 63 constituting the third heat exchange section 60C (third main heat exchange section 61C), the third The liquid side inlet / outlet communication space 85C communicates with the remaining five flat tubes 63 of the flat tubes 63 constituting the third heat exchange portion 60C (third sub heat exchange portion 62C). In the fourth inlet / outlet communication space 82D, the fourth gas side inlet / outlet communication space 84D communicates with the top nine of the flat tubes 63 constituting the fourth heat exchange section 60D (fourth main heat exchange section 61D), the fourth. The liquid side inlet / outlet communication space 85D communicates with the remaining four flat tubes 63 of the flat tube 63 constituting the fourth heat exchange portion 60D (fourth sub heat exchange portion 62D). In the fifth inlet / outlet communication space 82E, the fifth gas side inlet / outlet communication space 84E communicates with the top seven of the flat tubes 63 constituting the fifth heat exchange section 60E (fifth main heat exchange section 61E), The liquid side inlet / outlet communication space 85E communicates with the remaining four flat tubes 63 of the flat tube 63 constituting the fifth heat exchange unit 60E (fifth sub heat exchange unit 62E). In the sixth inlet / outlet communication space 82F, the sixth gas side inlet / outlet communication space 84F communicates with the top six of the flat tubes 63 constituting the sixth heat exchange section 60F (sixth main heat exchange section 61F), sixth The liquid side inlet / outlet communication space 85F communicates with the remaining three flat tubes 63 of the flat tube 63 constituting the sixth heat exchanging portion 60F (sixth sub heat exchanging portion 62F). In the first inlet / outlet communication space 82A, the first upper gas side inlet / outlet communication space 84AU, which is one of the first gas side inlet / outlet communication spaces 84A, communicates with the top twelve of the flat tubes 63 constituting the first heat exchange section 60A. (The first upper main heat exchanging portion 61AU which is one of the first main heat exchanging portions 61A). In the first inlet / outlet communication space 82A, the first lower gas side inlet / outlet communication space 84AL, which is the other side of the first gas side inlet / outlet communication space 84A, has two flat pipes 63 constituting the first heat exchange section 60A from the bottom. It communicates with the book (the first lower main heat exchange section 61AL which is the other of the first main heat exchange sections 61A). Furthermore, in the first inlet / outlet communication space 82A, the first liquid side inlet / outlet communication space 85A communicates with the remaining seven flat tubes 63 constituting the first heat exchange section 60A (first sub heat exchange section 62A).

  Further, the first header collecting pipe 80 includes a liquid side diverting member 70 for diverting the refrigerant sent from the outdoor expansion valve 12 (see FIG. 1) during heating operation to the liquid side inlet / outlet communication spaces 85A to 85F, and for cooling. A gas side diverting member 75 that diverts and sends the refrigerant sent from the compressor 8 (see FIG. 1) during operation to the gas side inlet / outlet communication spaces 84A to 84F is connected.

  The liquid side diverting member 70 extends from the liquid side refrigerant diverter 71 connected to the refrigerant pipe 20 (see FIG. 1) and the liquid side refrigerant diverter 71 and is connected to the liquid side inlet / outlet communication spaces 85A to 85F. Liquid side refrigerant distribution pipes 72A to 72F. Here, the liquid side refrigerant distribution pipes 72A to 72F have capillary tubes, and those having a length and an inner diameter corresponding to the distribution ratio to the sub heat exchange parts 62A to 62F are used.

  The gas side branch member 75 extends from the gas side refrigerant branch mother pipe 76 connected to the refrigerant pipe 19 (see FIG. 1) and the gas side refrigerant branch mother pipe 76 and is connected to the gas side inlet / outlet communication spaces 84A to 84F. Gas side refrigerant branch branch pipes 77A to 77F. Here, since the first gas side inlet / outlet communication space 84A includes the first upper gas side inlet / outlet communication space 84AU and the first lower gas side inlet / outlet communication space 84AL, the gas side refrigerant branch main pipe 76 is provided. The first gas-side refrigerant branch branch tube 77A extending from the first pipe also has a first upper gas-side refrigerant branch branch tube 77AU and a first lower gas-side refrigerant branch branch tube 77AL.

  As for the 2nd header collection pipe 90, the internal space is divided up and down by the partition plate 91, and the folding | returning communication space 92A-92F corresponding to each heat exchange part 60A-60F is formed. The first folded communication space 92A corresponding to the first heat exchange section 60A is partitioned into two upper and lower parts by the partition plate 93, so that the upper first upper folded communication space 92AU and the lower first lower side are separated. A folded communication space 92AL is formed. As described above, the internal space of the second header collecting pipe 90 is not limited to the configuration that is only partitioned by the partition plates 91 and 93, but the refrigerant flow state in the second header collecting pipe 90 The structure by which the device for maintaining favorable was made may be sufficient.

  And each return | turnback communication space 92A-92F is connected to all the flat tubes 63 which comprise the corresponding heat exchange parts 60A-60F. That is, the second folded communication space 92B communicates with all of the 18 flat tubes 63 that constitute the second heat exchange section 60B. The third folded communication space 92C communicates with all of the 15 flat tubes 63 constituting the third heat exchange unit 60C. The fourth folded communication space 92D communicates with all of the 13 flat tubes 63 constituting the fourth heat exchange unit 60D. The fifth folded communication space 92E communicates with all the eleven flat tubes 63 constituting the fifth heat exchange unit 60E. The sixth folded communication space 92F communicates with all nine flat tubes 63 constituting the sixth heat exchange unit 60F. The first folded communication space 92A communicates with all of the 21 flat tubes 63 constituting the first heat exchange section 60A. Here, the first upper folded communication space 92AU, which is the upper portion of the first folded communication space 92A, communicates with the top 17 of the 21 flat tubes 63 constituting the first heat exchange section 60A. Further, the first lower folded communication space 92AL, which is the lower portion of the first folded communication space 92A, includes a lowermost flat tube 63A among the 21 flat tubes 63 constituting the first heat exchange section 60A. It communicates with four. Of the 17 flat tubes 63 communicating with the first upper folded communication space 92AU, the twelve flat tubes 63 from the top serve as the first upper main heat exchange portion 61AU, which is one of the first main heat exchange portions 61A. The remaining five flat tubes 63 constitute a first upper sub heat exchange portion 62AU that is an upper portion of the first sub heat exchange portion 62A. Of the four flat tubes 63 communicating with the first lower folded communication space 92AL, the two flat tubes 63 including the lowermost flat tube 63A are the other of the first main heat exchange portions 61A. The first lower main heat exchanging part 61AL is configured, and the remaining two flat tubes 63 configure the first lower sub heat exchanging part 62AL which is the lower part of the first sub heat exchanging part 62A. Yes.

  Thereby, each heat exchange part 60A-60F is the sub heat exchange part connected in series to main heat exchange part 61A-61F in the vertical position different from main heat exchange part 61A-61F and main heat exchange part 61A-61F. 62A-62F. That is, the second heat exchange unit 60B is positioned directly below the 12 flat tubes 63 constituting the second main heat exchange unit 61B communicating with the second gas side inlet / outlet communication space 84B and the second main heat exchange unit 61B. And the six flat tubes 63 constituting the second sub heat exchange section 62B communicating with the second liquid side inlet / outlet communication space 85B are connected in series through the second folded communication space 92B. Yes. The third heat exchange part 60C is located immediately below the ten flat tubes 63 constituting the third main heat exchange part 61C communicating with the third gas side inlet / outlet communication space 84C and the third main heat exchange part 61C. The five flat tubes 63 constituting the third sub heat exchange portion 62C communicating with the third liquid side inlet / outlet communication space 85C are connected in series through the third folded communication space 92C. The fourth heat exchange part 60D is located directly below the nine flat tubes 63 constituting the fourth main heat exchange part 61D communicating with the fourth gas side inlet / outlet communication space 84D and the fourth main heat exchange part 61D. The four flat tubes 63 constituting the fourth sub heat exchanging portion 62D communicating with the fourth liquid side inlet / outlet communication space 85D are connected in series through the fourth folded communication space 92D. The fifth heat exchanging part 60E is located immediately below the seven flat tubes 63 constituting the fifth main heat exchanging part 61E communicating with the fifth gas side inlet / outlet communication space 84E and the fifth main heat exchanging part 61E. The four flat tubes 63 constituting the fifth sub heat exchange section 62E communicating with the fifth liquid side inlet / outlet communication space 85E are connected in series through the fifth return communication space 92E. The sixth heat exchange part 60F is located directly below the six flat tubes 63 constituting the sixth main heat exchange part 61F communicating with the sixth gas side inlet / outlet communication space 84F and the sixth main heat exchange part 61F. The three flat tubes 63 constituting the sixth sub heat exchange part 62F communicating with the sixth liquid side inlet / outlet communication space 85F are connected in series through the sixth folded communication space 92F. The first heat exchange unit 60A includes fourteen flat tubes 63 constituting the first main heat exchange unit 61A communicating with the first gas side inlet / outlet communication space 84A and the first liquid side inlet / outlet communication space 85A. The seven flat tubes 63 constituting the sub heat exchange section 62A are connected in series through the first folded communication space 92A. Here, the first heat exchanging unit 60A has two upper and lower heat exchanging units 60AU and 60AL. The first upper heat exchange unit AU includes twelve flat tubes 63 constituting the first upper main heat exchange unit 61AU communicating with the first upper gas side inlet / outlet communication space 84AU, and directly below the first upper main heat exchange unit 61AU. The five flat tubes 63 constituting the first upper sub heat exchanging portion 62AU communicating with the first liquid side inlet / outlet communication space 85A are connected in series through the first upper folded communication space 92AU. have. The first lower heat exchange portion AL includes two flat tubes 63 including a lowermost flat tube 63A constituting the first lower main heat exchange portion 61AL communicating with the first lower gas side inlet / outlet communication space 84AL. Two flat tubes 63 that constitute the first lower sub heat exchange portion 62AL that is located immediately above the first lower main heat exchange portion 61AL and communicates with the first liquid side inlet / outlet communication space 85A. 1 It has the structure connected in series through the lower return communication space 92AL.

  Thus, here, a plurality of flat tubes 63 arranged vertically and having a refrigerant passage 63b formed therein, and a plurality of ventilation paths through which air flows between the adjacent flat tubes 63 are divided. And fins 64. The flat tube 63 is divided into a plurality of heat exchange units 60A to 60F. The heat exchange units 60A to 60F are main heat exchange units 61A to 61F and main positions at different vertical positions from the main heat exchange units 61A to 61F. And sub heat exchange units 62A to 62F connected in series to the heat exchange units 61A to 61F. And the 1st main heat exchange part 61A which comprises the 1st heat exchange part 60A containing the lowermost flat tube 63A among several heat exchange parts 60A-60F is arrange | positioned so that the lowermost flat pipe 63A may be included. ing.

  In addition, here, all of the heat exchange units 60B to 60F other than the first heat exchange unit 60A are arranged above the first heat exchange unit 60A. The first sub heat exchange unit 62A includes a first upper sub heat exchange unit 62AU and a first lower sub heat exchange unit 62AL below the first upper sub heat exchange unit 62AU. Moreover, the first main heat exchange unit 61A includes a first upper main heat exchange unit 61AU connected to the first upper sub heat exchange unit 62AU above the first upper sub heat exchange unit 62AU, and a first lower sub heat exchange. A first lower main heat exchange unit 61AL connected to the first lower sub heat exchange unit 62AL is provided below the exchange unit 62AL.

  In addition, here, the ratio of the number (two) of the flat tubes 63 constituting the first lower main heat exchange section 61AL to the number (two) of the flat tubes 63 constituting the first lower sub heat exchange section 62AL. (= 2/2 = 1.0) is the number of flat tubes 63 constituting the first upper main heat exchanging portion 61AU with respect to the number of flat tubes 63 constituting the first upper sub heat exchanging portion 62AU (five). 12) is set to be smaller than the ratio (= 12/5 = 2.4). The ratio of the number of flat tubes 63 constituting the first lower main heat exchange portion 61AL to the number of flat tubes 63 constituting the first lower sub heat exchange portion 62AL is not limited to 1.0. However, it is preferably within the range of 0.5 to 1.5. The ratio of the number of flat tubes 63 constituting the first upper main heat exchange portion 61AU to the number of flat tubes 63 constituting the first upper sub heat exchange portion 62AU is not limited to 2.4. It is preferable to be within the range of 1.7 to 3.0.

  In addition, here, the heat exchange units 60A to 60F are arranged side by side, and the heat exchange units 60B to 60F other than the first heat exchange unit 60A are sub-heated below the main heat exchange units 61B to 61F. Exchange parts 62B-62F are arranged.

  Next, the flow of the refrigerant in the outdoor heat exchanger 11 having the above configuration will be described.

  During the cooling operation, the outdoor heat exchanger 11 functions as a radiator for the refrigerant discharged from the compressor 8 (see FIG. 1).

  The refrigerant discharged from the compressor 8 (see FIG. 1) is sent to the gas side branch member 75 through the refrigerant pipe 19 (see FIG. 1). The refrigerant sent to the gas side diverting member 75 is diverted from the gas side refrigerant diverting mother pipe 76 to the gas side refrigerant diverting branch pipes 77AU, 77AL, 77B to 77F, and the respective gas side inlets and outlets of the first header collecting pipe 80. It is sent to the communication spaces 84AU, 84AL, 84B to 84F.

  The refrigerant sent to the gas side inlet / outlet communication spaces 84AU, 84AL, 84B to 84F is a flat tube 63 that constitutes the main heat exchange portions 61AU, 61AL, 61B to 61F of the corresponding heat exchange portions 60AU, 60AL, 60B to 60F. To be diverted to The refrigerant sent to each flat tube 63 is dissipated by heat exchange with outdoor air while flowing through the passage 63b, and merges in the folded communication spaces 92AU, 92AL, 92B to 92F of the second header collecting pipe 90. . That is, the refrigerant passes through the main heat exchange units 61AU, 61AL, 61B to 61F. At this time, the refrigerant dissipates heat from the superheated gas state until it becomes a liquid state close to a gas-liquid two-phase state or a saturated state.

  The refrigerant merged in each of the folded communication spaces 92AU, 92L, 92B to 92F is diverted to the flat tubes 63 that constitute the sub heat exchange portions 62AU, 62AL, 62B to 62F of the corresponding heat exchange portions 60AU, 60AL, 60B to 60F. The The refrigerant sent to each flat tube 63 dissipates heat by exchanging heat with outdoor air while flowing through the passage 63b, and merges in the liquid side inlet / outlet communication spaces 85A to 85F of the first header collecting pipe 80. That is, the refrigerant passes through the sub heat exchange units 62AU, 62AL, 62B to 62F. At this time, the refrigerant further dissipates heat until it becomes a supercooled liquid state from a liquid state close to a gas-liquid two-phase state or a saturated state.

  The refrigerant sent to each of the liquid side inlet / outlet communication spaces 85 </ b> A to 85 </ b> F is sent to the liquid side refrigerant diversion pipes 72 </ b> A to 72 </ b> F of the liquid side refrigerant diversion member 70 and merges in the liquid side refrigerant diverter 71. The refrigerant merged in the liquid side refrigerant divider 71 is sent to the outdoor expansion valve 12 (see FIG. 1) through the refrigerant pipe 20 (see FIG. 1).

  During the heating operation, the outdoor heat exchanger 11 functions as an evaporator for the refrigerant decompressed by the outdoor expansion valve 12 (see FIG. 1).

  The refrigerant decompressed in the outdoor expansion valve 12 is sent to the liquid side refrigerant distribution member 70 through the refrigerant pipe 20 (see FIG. 1). The refrigerant sent to the liquid side refrigerant diverting member 70 is diverted from the liquid side refrigerant diverter 71 to the liquid side refrigerant diverting pipes 72A to 72F, and the liquid side inlet / outlet communication spaces 85A to 85F of the first header collecting pipe 80 are separated. Sent to.

  The refrigerant sent to each of the liquid side inlet / outlet communication spaces 85A to 85F is diverted to the flat tubes 63 constituting the sub heat exchange portions 62AU, 62AL, 62B to 62F of the corresponding heat exchange portions 60AU, 60AL, 60B to 60F. . The refrigerant sent to each flat tube 63 evaporates by heat exchange with outdoor air while flowing through the passage 63b, and merges in each folded communication space 92AU, 92AL, 92B to 92F of the second header collecting tube 90. . That is, the refrigerant passes through the sub heat exchange units 62AU, 62AL, 62B to 62F. At this time, the refrigerant evaporates from a gas-liquid two-phase state with a lot of liquid components to a gas state close to a saturated state with a gas-liquid two-phase state with many gas components.

  The refrigerant merged in each of the folded communication spaces 92AU, 92AL, 92B to 92F is diverted to the flat pipe 63 constituting the main heat exchange portions 61AU, 61AL, 61B to 61F of the corresponding heat exchange portions 60AU, 60AL, 60B to 60F. The The refrigerant sent to each flat tube 63 is evaporated (heated) by heat exchange with outdoor air while flowing through the passage 63b, and the gas side inlet / outlet communication spaces 84AU, 84AL of the first header collecting pipe 80 are evaporated. , 84B to 84F. That is, the refrigerant passes through the main heat exchange units 61AU, 61AL, 61B to 61F. At this time, the refrigerant is further evaporated (heated) from a gas-liquid two-phase state with a lot of gas components or a gas state close to saturation to a superheated gas state.

  The refrigerant sent to the gas side inlet / outlet communication spaces 84AU, 84AL, 84B to 84F is sent to the gas side refrigerant branch branches 77AU, 77AL, 77B to 77F of the gas side refrigerant diverting member 75, and the gas side refrigerant diversion base. Merge at the pipe 76. The refrigerant merged in the gas-side refrigerant branch mother pipe 76 is sent to the suction side of the compressor 8 (see FIG. 1) through the refrigerant pipe 19 (see FIG. 1).

  During the defrosting operation, the outdoor heat exchanger 11 functions as a radiator for the refrigerant discharged from the compressor 8 (see FIG. 1), similarly to the cooling operation. In addition, since the flow of the refrigerant in the outdoor heat exchanger 11 during the defrosting operation is the same as that during the cooling operation, the description thereof is omitted here. However, unlike the cooling operation, during the defrosting operation, the refrigerant mainly dissipates heat while melting the frost attached to the heat exchange units 60AU, 60AL, 60B to 60F.

(4) Features The outdoor heat exchanger 11 (heat exchanger) of this embodiment has the following features.

<A>
As described above, the heat exchanger 11 of the present embodiment includes a plurality of flat tubes 63 that are arranged one above the other and that have a refrigerant passage 63b formed therein, and a plurality of air that flows between adjacent flat tubes 63. And a plurality of fins 64 that are partitioned into the ventilation path. The flat tube 63 is divided into a plurality of heat exchange units 60A to 60F. The heat exchange units 60A to 60F are main heat exchange units 61A to 61F and main positions at different vertical positions from the main heat exchange units 61A to 61F. And sub heat exchange units 62A to 62F connected in series to the heat exchange units 61A to 61F. And here, the 1st main heat exchanging part 61A which constitutes the 1st heat exchanging part 60A containing the lowermost flat tube 63A among a plurality of heat exchanging parts 60A-60F seems to contain the lowermost flat pipe 63A. Is arranged.

  On the other hand, in the conventional heat exchanger, a plurality of flat tubes are divided into a plurality of heat exchanging portions arranged vertically, and each heat exchanging portion is below the main heat exchanging portion and the main heat exchanging portion. And a sub heat exchange part connected in series to the main heat exchange part. For this reason, in the conventional heat exchanger, the sub heat exchanging portion constituting the lowermost heat exchanging portion of the heat exchanging portions is arranged to include the lowermost flat tube (flat tube 63A in the present embodiment). ing. And when such a conventional heat exchanger is employed in an air conditioner that switches between heating operation and defrosting operation, it melts the frost adhering to the lowermost heat exchange part during the defrosting operation. The required time tends to be longer than the time required to melt the frost attached to the heat exchange part on the upper stage side than the lowermost heat exchange part. First, the cause will be described.

  In this conventional configuration, when switching from heating operation (used as a refrigerant evaporator) to defrosting operation (used as a refrigerant radiator), a liquid state is placed in the lowermost sub heat exchange section including the lowermost flat tube. The refrigerant is easy to accumulate. Then, when the defrosting operation is performed in such a state, the refrigerant in the gas state first flows into the lowermost main heat exchange part, and then flows into the lowermost sub heat exchange part. It takes time to evaporate the liquid refrigerant accumulated in the sub heat exchange section. That is, in the configuration of the conventional heat exchanger, the lowermost sub heat exchange section including the lowermost flat tube during the defrosting operation is located on the downstream side of the refrigerant flow. It is estimated that this is one of the causes that the time required to melt the frost attached to the replacement part becomes long.

  Further, in this conventional configuration, when the refrigerant in the gas state branches during defrosting operation and flows into the main heat exchange part of each heat exchange part, the heat exchange on the upper stage side is affected by the influence of the liquid head of the refrigerant. The flow rate of the refrigerant in the gas state flowing into the lowermost heat exchanging portion is smaller than that of the lower portion, and the time required for melting the frost attached to the lowermost heat exchanging portion is lengthened. Since the degree of the liquid head is affected by the height position of the flat tube included in the sub heat exchange unit constituting the heat exchange unit, the lowermost sub heat exchange unit includes the lowermost flat tube. And the liquid head of a refrigerant | coolant is large and the flow volume of the refrigerant | coolant of the gas state which flows in at the time of a defrost operation further decreases. That is, in the configuration of the conventional heat exchanger, the flow rate of the refrigerant in the gas state flowing into the lowermost heat exchanging part by the refrigerant liquid head during the defrosting operation is reduced. It is presumed that this is one of the causes that the time required to melt the frost attached to the surface becomes longer.

  Further, in this conventional configuration, since the lower end portion of the fin close to the lowermost flat tube is in contact with the drain pan (the bottom frame 42 in the present embodiment), the lowermost sub heat exchange section including the lowermost flat tube Heat is easily generated from to the drain pan. And, when the defrosting operation is performed in such a state, the heat in the lowermost heat exchanging portion is less likely to rise than the upper heat exchanging portion due to heat radiation from the lowermost sub heat exchanging portion to the drain pan. The time required to melt the frost adhering to the lowermost heat exchanging portion is lengthened. That is, in the conventional heat exchanger configuration, the heat radiation from the lowermost sub heat exchange part including the lowermost flat tube to the drain pan melts the frost adhering to the lowermost heat exchange part during the defrosting operation. It is presumed that this is one of the causes of the longer time required for

  As described above, in the conventional heat exchanger, when the lowermost sub heat exchanging portion includes the lowermost flat tube, the heating exchanger and the defrosting operation are switched to each other and the air conditioner is used. In addition, the time required to melt the frost attached to the lowermost heat exchange part is longer than the time required to melt the frost attached to the upper heat exchange part than the lowermost heat exchange part. Presumed to be longer.

  Therefore, here, unlike the conventional heat exchanger, as described above, the first main heat exchange part constituting the first heat exchange part 60A including the lowermost flat tube 63A among the heat exchange parts 60A to 60F. 61A is arranged so as to include the lowermost flat tube 63A.

  And when the heat exchanger 11 which has this structure is employ | adopted for the air conditioning apparatus 1 which switches between heating operation and defrost operation as mentioned above, when it pays attention to the 1st heat exchange part 60A, heating operation At the time of (used as a refrigerant evaporator), as shown in FIG. 8, the gas-liquid two-phase refrigerant flows into the first sub-heat exchanger 62A and flows into the first sub-heat exchanger 62A, as shown in FIG. The refrigerant in the state passes through the first sub heat exchange part 62A and the first main heat exchange part 61A including the lowermost flat tube 63A and is heated in this order, and flows out from the first heat exchange part 60A. Further, during the defrosting operation (used as a refrigerant radiator), as shown in FIG. 9, the gas state refrigerant flows into the first main heat exchange unit 61 </ b> A and into the first main heat exchange unit 61 </ b> A. The refrigerant passes through the first main heat exchange unit 61A including the lowermost flat tube 63A and the first sub heat exchange unit 62A in order, is cooled, and flows out from the first heat exchange unit 60A. That is, here, during the defrosting operation, the first main heat exchanging portion 61A including the lowermost flat tube 63A is positioned on the upstream side of the refrigerant flow. Therefore, here, the refrigerant in the gas state is allowed to flow into the first main heat exchange section 61A including the lowermost flat tube 63A, and the refrigerant in the liquid state collected in the first sub heat exchange section 62A in the lowermost stage is positively While heating and evaporating, it becomes possible to quickly increase the temperature in the first heat exchange section 60A in the lowermost stage, and thereby, during the defrosting operation as compared with the case where a conventional heat exchanger is employed. The time required to melt the frost attached to the lowermost heat exchange section 63A can be shortened.

  Thus, here, by adopting the heat exchanger 11 having the above-described configuration in the air conditioner 1 that performs switching between the heating operation and the defrosting operation, the lowermost heat exchanging unit 60A is used in the defrosting operation. The time required for melting the attached frost can be shortened.

<B>
In the heat exchanger 11 of the present embodiment, as described above, all of the heat exchange units 60B to 60F other than the first heat exchange unit 60A are arranged above the first heat exchange unit 60A. The first sub heat exchange unit 62A includes a first upper sub heat exchange unit 62AU and a first lower sub heat exchange unit 62AL below the first upper sub heat exchange unit 62AU. Moreover, the first main heat exchange unit 61A includes a first upper main heat exchange unit 61AU connected to the first upper sub heat exchange unit 62AU above the first upper sub heat exchange unit 62AU, and a first lower sub heat exchange. A first lower main heat exchange unit 61AL connected to the first lower sub heat exchange unit 62AL is provided below the exchange unit 62AL.

  In this configuration, when focusing on the first heat exchange unit 60A, during heating operation (used as a refrigerant evaporator), as shown in FIG. 8, the gas-liquid two-phase refrigerant is converted into the first upper sub heat exchange unit 62AU and It flows into the first lower sub heat exchanger 62AL. The refrigerant in the gas-liquid two-phase state that has flowed into the first upper sub heat exchange unit 62AU is the first upper main heat exchange located above the first upper sub heat exchange unit 62AU and the first upper sub heat exchange unit 62AU. It passes through the part 61AU in order, is heated, and flows out from 60 A of 1st heat exchange parts. The refrigerant in the gas-liquid two-phase state that has flowed into the first lower sub heat exchange unit 62AL is a first lower main located below the first lower sub heat exchange unit 62AL and the first lower sub heat exchange unit 62AL. The heat exchange unit 61AL is passed through in order and heated, and flows out from the first heat exchange unit 60A. Further, during the defrosting operation (used as a refrigerant radiator), as shown in FIG. 9, the gaseous refrigerant flows into the first upper main heat exchange unit 61AU and the first lower main heat exchange unit 61AL. And the refrigerant | coolant of the gas state which flowed into 1st upper side main heat exchange part 61AU is 1st upper side main heat exchange part 61AU and 1st upper side sub heat exchange part 62AU located under 1st upper side main heat exchange part 61AU. It passes through in order, is cooled, and flows out from 60 A of 1st heat exchange parts. The refrigerant in the gas state flowing into the first lower main heat exchange unit 61AL is the first lower main heat exchange unit 61AL and the first lower sub heat exchange unit located above the first lower main heat exchange unit 61AL. It passes through 62AL in order, is cooled, and flows out from the first heat exchange section 60A.

<C>
Further, as described above, the heat exchanger 11 of the present embodiment has the flat tubes 63 constituting the first lower main heat exchange portion 61AL corresponding to the number of flat tubes 63 constituting the first lower sub heat exchange portion 62AL. Is set to be smaller than the ratio of the number of flat tubes 63 constituting the first upper main heat exchanging portion 61AU to the number of flat tubes 63 constituting the first upper sub-heat exchanging portion 62AU. Yes.

  In the configuration <B>, the first upper sub heat exchange unit 62AU is disposed below the first upper main heat exchange unit 61AU, and the first lower main heat exchange unit 62AL is disposed below the first lower sub heat exchange unit 62AL. It becomes the structure which has 60 A of 1st heat exchange parts by which heat exchange part 61AL is arrange | positioned. In this configuration, during heating operation (used as a refrigerant evaporator), as shown in FIG. 8, the first lower sub heat exchange unit 62AL and the first lower main heat exchange unit 61AL in the first heat exchange unit 60A. The first lower main heat exchanging part (first lower heat exchanging part 60AL) is arranged below the first lower sub heat exchanging part 62AL after the refrigerant has passed through the first lower sub heat exchanging part 62AL. It will function as a so-called downflow type evaporator passing through 61AL. Here, in a downflow type evaporator, when a fluid in a gas-liquid two-phase state is sent downward and accompanied by a fluid diversion, fluid drift tends to occur. Therefore, also in the first lower sub heat exchange unit 62AL and the first lower main heat exchange unit 61AL, the first lower main heat exchange unit 61AL from the flat tube 63 constituting the first lower sub heat exchange unit 62AL. Since the refrigerant is diverted when the refrigerant is sent downward to the flat tube 63 constituting the refrigerant, there is a possibility that the refrigerant drifts. At this time, if the ratio of the number of flat tubes 63 constituting the first lower main heat exchange portion 61AL to the number of flat tubes 63 constituting the first lower sub heat exchange portion 62AL increases, refrigerant drift occurs. The fear increases.

  Therefore, here, as described above, for the first heat exchange section 60A, the flatness constituting the first lower main heat exchange section 61AL with respect to the number of flat tubes 63 constituting the first lower sub heat exchange section 62AL. The ratio of the number of tubes 63 is set so as to be smaller than the ratio of the number of flat tubes 63 constituting the first upper main heat exchange section 61AU to the number of flat tubes 63 constituting the first upper sub heat exchange section 62AU. doing.

  Accordingly, here, during the heating operation (used as a refrigerant evaporator), from the flat tube 63 constituting the first lower sub heat exchange portion 62AL to the flat tube 63 constituting the first lower main heat exchange portion 61AU. When sending the refrigerant downward, it is possible to suppress the drift of the refrigerant accompanying the flow of the refrigerant.

<D>
Moreover, as for the heat exchanger 11 of this embodiment, the heat exchange parts 60A-60F are arrange | positioned along with the upper and lower sides as mentioned above, and heat exchange parts 60B-60F other than 60 A of 1st heat exchange parts, Sub heat exchange parts 62B-62F are arranged below main heat exchange parts 61B-61F.

  In this configuration, focusing on the heat exchange units 60B to 60F other than the first heat exchange unit 60A, the refrigerant in the gas-liquid two-phase state is transferred to the sub heat exchange units 62B to 62F during heating operation (used as a refrigerant evaporator). The refrigerant in the gas-liquid two-phase state that flows in and flows into the sub heat exchange units 62B to 62F passes through the sub heat exchange units 62B to 62F and the main heat exchange units 61B to 61F located above the sub heat exchange units 62B to 62F. It passes and heats in order, and flows out from the heat exchange parts 60B-60F. Further, during the defrosting operation (used as a refrigerant radiator), the gaseous refrigerant flows into the main heat exchange units 61B to 61F, and the gaseous refrigerant that has flowed into the main heat exchange units 61B to 61F undergoes main heat exchange. The parts 61B to 61F and the sub heat exchanging parts 62B to 62F located below the main heat exchanging parts 61B to 61F are passed through and cooled in this order, and flow out of the heat exchanging parts 60B to 60F.

(5) Modification <A>
In the outdoor heat exchanger 11 (heat exchanger) of the above-described embodiment, the lowermost first heat exchange unit 60A including the lowermost flat tube 63A is included in the main heat exchange unit 61A so that the lowermost flat tube 63A is included. The first heat exchanging unit 60A, the first upper heat exchanging unit 60AU, and the first lower main heat exchanging unit 61AL are arranged to include the lowermost flat tube 63A. This is realized by dividing into an exchange unit 60AL (see FIGS. 6 to 9). In this configuration, two partition plates 86 are provided in the first header collecting pipe 80 so as to partition the first inlet / outlet communication space 82A corresponding to the first heat exchange part 60A into three inlet / outlet communication spaces 84AU, 85A, 84AL, and The partition plate 93 is provided in the second header collecting pipe 90 so as to partition the first folded communication space 92A corresponding to the first heat exchange section 60A into two folded communication spaces 92AU and 92AL. In this configuration, the first liquid side inlet / outlet communication space 85A is a liquid side inlet / outlet communication space common to the first upper heat exchange part 60AU and the first lower heat exchange part 60AL, and in this sense, the first upper heat The exchange unit 60AU and the first lower heat exchange unit 60AL are not independent heat exchange units.

  However, the configuration in which the lowermost first heat exchanging portion 60A including the lowermost flat tube 63A is arranged so that the main heat exchanging portion 61A includes the lowermost flat tube 63A is not limited thereto.

  For example, in the heat exchanger 11 of the above embodiment, the first header collecting pipe 80 is further provided with a partition plate that divides the first liquid side inlet / outlet communication space 85A into two upper and lower parts, thereby providing two liquid side inlet / outlet communication spaces, The first upper heat exchange unit 60AU and the first lower heat exchange unit 60AL may be independent heat exchange units.

  Specifically, in the outdoor heat exchanger 11 of this modification, as shown in FIGS. 10 to 14, a plurality of (here, seven) heat exchange units 60 </ b> A to 60 </ b> G in which a plurality of flat tubes 63 are arranged vertically. It is divided into. Specifically, here, in order from the bottom to the top, the first heat exchange unit 60A, the second heat exchange unit 60B, which is the lowest heat exchange unit, the sixth heat exchange unit 60F, and the seventh heat An exchange unit 60G is formed. The first heat exchange section 60A has four flat tubes 63 including a flat tube 63A at the lowest stage. The second heat exchanging unit 60B has 17 flat tubes 63. The third heat exchanging unit 60 </ b> C has 18 flat tubes 63. The fourth heat exchanging unit 60 </ b> D has 15 flat tubes 63. The fifth heat exchanging unit 60 </ b> E has 13 flat tubes 63. The sixth heat exchange part 60F has eleven flat tubes 63. The seventh heat exchanging part 60G has nine flat tubes 63.

  The first header collecting pipe 80 is partitioned into upper and lower portions by a partition plate 81, thereby forming entrance / exit communication spaces 82 </ b> A to 82 </ b> G corresponding to the heat exchange units 60 </ b> A to 60 </ b> G. In addition, each of the entrance / exit communication spaces 82 </ b> A to 82 </ b> G is divided into two vertically by a partition plate 83. Thereby, the upper side gas side inlet / outlet communication spaces 84B to 84G and the lower side liquid side inlet / outlet communication space are provided in the inlet / outlet communication spaces 82B to 82G excluding the first inlet / outlet communication space 82A corresponding to the first heat exchange section 60A. 85B to 85G are formed, and an upper first liquid side inlet / outlet communication space 85A and a lower first gas side inlet / outlet communication are provided in the first inlet / outlet communication space 82A corresponding to the first heat exchange section 60A. A space 84A is formed.

  The second gas side inlet / outlet communication space 84B communicates with the top twelve of the flat tubes 63 that constitute the second heat exchange section 60B, and the second liquid side inlet / outlet communication space 85B includes the second heat exchange section 60B. Are communicated with the remaining five flat tubes 63. The third gas side inlet / outlet communication space 84C communicates with twelve from the top of the flat tubes 63 constituting the third heat exchange part 60C, and the third liquid side inlet / outlet communication space 85C constitutes the third heat exchange part 60C. The remaining six flat tubes 63 communicate with the remaining flat tubes 63. The fourth gas side inlet / outlet communication space 84D communicates with the top ten of the flat tubes 63 that constitute the fourth heat exchange part 60D, and the fourth liquid side inlet / outlet communication space 85D constitutes the fourth heat exchange part 60D. The remaining five flat tubes 63 communicate with the remaining flat tubes 63. The fifth gas side inlet / outlet communication space 84E communicates with nine of the flat tubes 63 constituting the fifth heat exchanging part 60E from the top, and the fifth liquid side inlet / outlet communication space 85E constitutes the fifth heat exchange part 60E. The remaining four flat tubes 63 communicate with the remaining flat tubes 63. The sixth gas side inlet / outlet communication space 84F communicates with seven of the flat tubes 63 constituting the sixth heat exchange part 60F from the top, and the sixth liquid side inlet / outlet communication space 85F constitutes the sixth heat exchange part 60F. The remaining four flat tubes 63 communicate with the remaining flat tubes 63. The seventh gas side inlet / outlet communication space 84G communicates with the top six of the flat tubes 63 constituting the seventh heat exchange part 60G, and the seventh liquid side inlet / outlet communication space 85G constitutes the seventh heat exchange part 60G. The remaining three flat tubes 63 communicate with the remaining flat tubes 63. The first gas side inlet / outlet communication space 84A communicates from the bottom including the lowermost flat tube 63A among the flat tubes 63 constituting the first heat exchange section 60A, and the first liquid side inlet / outlet communication space 85A It communicates with the remaining two of the flat tubes 63 constituting the first heat exchange part 60A.

  Here, the flat tubes 63 communicating with the gas side inlet / outlet communication spaces 84A to 84G are referred to as main heat exchange portions 61A to 61G, and the flat tubes 63 communicating with the liquid side inlet / outlet communication spaces 85A to 85G are sub heat exchange portions 62A to 62G. And That is, in the second inlet / outlet communication space 82B, the second gas side inlet / outlet communication space 84B communicates with twelve from the top of the flat tubes 63 constituting the second heat exchange section 60B (second main heat exchange section 61B), The second liquid side inlet / outlet communication space 85B communicates with the remaining five flat tubes 63 of the flat tubes 63 constituting the second heat exchange section 60B (second sub heat exchange section 62B). In the third inlet / outlet communication space 82C, the third gas side inlet / outlet communication space 84C communicates with the top twelve of the flat tubes 63 constituting the third heat exchange section 60C (third main heat exchange section 61C), the third The liquid side inlet / outlet communication space 85C communicates with the remaining six flat tubes 63 of the flat tube 63 constituting the third heat exchange unit 60C (third sub heat exchange unit 62C). In the fourth inlet / outlet communication space 82D, the fourth gas-side inlet / outlet communication space 84D communicates with the top ten of the flat tubes 63 constituting the fourth heat exchange section 60D (fourth main heat exchange section 61D), the fourth. The liquid side inlet / outlet communication space 85D communicates with the remaining five flat tubes 63 of the flat tubes 63 constituting the fourth heat exchange portion 60D (fourth sub heat exchange portion 62D). In the fifth inlet / outlet communication space 82E, the fifth gas side inlet / outlet communication space 84E communicates with the top nine of the flat tubes 63 constituting the fifth heat exchange section 60E (fifth main heat exchange section 61E), fifth The liquid side inlet / outlet communication space 85E communicates with the remaining four flat tubes 63 of the flat tube 63 constituting the fifth heat exchange unit 60E (fifth sub heat exchange unit 62E). In the sixth inlet / outlet communication space 82F, the sixth gas side inlet / outlet communication space 84F communicates with the top seven of the flat tubes 63 constituting the sixth heat exchange section 60F (sixth main heat exchange section 61F), The liquid side inlet / outlet communication space 85F communicates with the remaining four flat tubes 63 of the flat tube 63 constituting the fifth heat exchanging portion 60F (sixth sub heat exchanging portion 62F). In the seventh inlet / outlet communication space 82G, the seventh gas side inlet / outlet communication space 84G communicates with the top six of the flat tubes 63 constituting the seventh heat exchange unit 60G (seventh main heat exchange unit 61G), The liquid side inlet / outlet communication space 85G communicates with the remaining three flat tubes 63 of the flat tube 63 constituting the seventh heat exchange unit 60G (seventh sub heat exchange unit 62G). In the first inlet / outlet communication space 82A, the first gas side inlet / outlet communication space 84A communicates from the bottom including the lowest flat tube 63A among the flat tubes 63 constituting the first heat exchange section 60A (first main The heat exchange part 61A) and the first liquid side inlet / outlet communication space 85A communicate with the remaining two flat tubes 63 constituting the first heat exchange part 60A (first sub heat exchange part 62A).

  Further, the first header collecting pipe 80 includes a liquid side diverting member 70 for diverting the refrigerant sent from the outdoor expansion valve 12 (see FIG. 1) during the heating operation to the liquid side inlet / outlet communication spaces 85A to 85G, and for cooling. A gas side diverting member 75 that diverts and sends the refrigerant sent from the compressor 8 (see FIG. 1) during operation to the gas side inlet / outlet communication spaces 84A to 84G is connected.

  The liquid side flow dividing member 70 extends from the liquid side refrigerant flow divider 71 connected to the refrigerant pipe 20 (see FIG. 1) and the liquid side refrigerant flow divider 71 and is connected to the liquid side inlet / outlet communication spaces 85A to 85G. Liquid side refrigerant distribution pipes 72A to 72G. Here, the liquid side refrigerant distribution pipes 72A to 72G have capillary tubes, and those having a length and an inner diameter corresponding to the distribution ratio to the sub heat exchange units 62A to 62G are used.

  The gas side branch member 75 extends from the gas side refrigerant branch mother pipe 76 connected to the refrigerant pipe 19 (see FIG. 1) and the gas side refrigerant branch mother pipe 76, and is connected to the gas side inlet / outlet communication spaces 84A to 84G. Gas side refrigerant branch branch pipes 77A to 77G.

  As for the 2nd header collection pipe 90, the internal space is divided up and down with the partition plate 91, and the folding | returning communication space 92A-92G corresponding to each heat exchange part 60A-60G is formed. As described above, the internal space of the second header collecting pipe 90 is not limited to the configuration just partitioned by the partition plate 91, and the flow state of the refrigerant in the second header collecting pipe 90 is good. It is also possible to adopt a configuration that is devised for maintaining the above.

  And each return | turnback communication space 92A-92G is connected to all the flat tubes 63 which comprise the corresponding heat exchange parts 60A-60G. That is, the second folded communication space 92B communicates with all of the 17 flat tubes 63 constituting the second heat exchange unit 60B. The third folded communication space 92C communicates with all of the 18 flat tubes 63 constituting the third heat exchange unit 60C. The fourth folded communication space 92D communicates with all of the 15 flat tubes 63 that constitute the fourth heat exchange unit 60D. The fifth folded communication space 92E communicates with all of the 13 flat tubes 63 constituting the fifth heat exchange unit 60E. The sixth folded communication space 92F communicates with all of the eleven flat tubes 63 constituting the sixth heat exchange unit 60F. The seventh folded communication space 92G communicates with all nine flat tubes 63 constituting the seventh heat exchange unit 60G. The first folded communication space 92A communicates with all of the four flat tubes 63 including the lowermost flat tube 63A constituting the first heat exchange section 60A.

  Thereby, each heat exchange part 60A-60G is the sub heat exchange part connected in series to main heat exchange part 61A-61G in the upper and lower positions different from main heat exchange part 61A-61G, and main heat exchange part 61A-61G. 62A-62G. That is, the second heat exchange unit 60B is positioned directly below the 12 flat tubes 63 constituting the second main heat exchange unit 61B communicating with the second gas side inlet / outlet communication space 84B and the second main heat exchange unit 61B. The five flat tubes 63 constituting the second sub heat exchange portion 62B communicating with the second liquid side inlet / outlet communication space 85B are connected in series through the second folded communication space 92B. Yes. The third heat exchange unit 60C is positioned directly below the twelve flat tubes 63 constituting the third main heat exchange unit 61C communicating with the third gas side inlet / outlet communication space 84C, and the third main heat exchange unit 61C. The six flat tubes 63 constituting the third sub heat exchange portion 62C communicating with the third liquid side inlet / outlet communication space 85C are connected in series through the third folded communication space 92C. The fourth heat exchange part 60D is located immediately below the ten flat tubes 63 constituting the fourth main heat exchange part 61D communicating with the fourth gas side inlet / outlet communication space 84D and the fourth main heat exchange part 61D. The five flat tubes 63 constituting the fourth sub heat exchange section 62D communicating with the fourth liquid side inlet / outlet communication space 85D are connected in series through the fourth folded communication space 92D. The fifth heat exchanging part 60E is located immediately below the nine flat tubes 63 constituting the fifth main heat exchanging part 61E communicating with the fifth gas side inlet / outlet communication space 84E and the fifth main heat exchanging part 61E. The four flat tubes 63 constituting the fifth sub heat exchange section 62E communicating with the fifth liquid side inlet / outlet communication space 85E are connected in series through the fifth return communication space 92E. The sixth heat exchange part 60F is located directly below the seven flat tubes 63 constituting the sixth main heat exchange part 61F communicating with the sixth gas side inlet / outlet communication space 84F and the sixth main heat exchange part 61F. The four flat tubes 63 constituting the sixth sub heat exchange part 62F communicating with the sixth liquid side inlet / outlet communication space 85F are connected in series through the sixth folded communication space 92F. The seventh heat exchanging part 60G is located immediately below the six flat tubes 63 constituting the seventh main heat exchanging part 61G communicating with the seventh gas side inlet / outlet communication space 84G and the seventh main heat exchanging part 61G. The three flat tubes 63 constituting the seventh sub heat exchange portion 62G communicating with the seventh liquid side inlet / outlet communication space 85G are connected in series through the seventh folded communication space 92G. The first heat exchange section 60A includes two flat pipes 63 including a lowermost flat pipe 63A constituting the first main heat exchange section 61A communicating with the first gas side inlet / outlet communication space 84A, and the first main heat exchange. Two flat tubes 63 that constitute the first sub heat exchange portion 62A that is located immediately above the portion 61A and communicates with the first liquid side inlet / outlet communication space 85A are connected in series through the first folded communication space 92A. It has a configuration.

  As described above, as in the above-described embodiment, a plurality of flat tubes 63 that are arranged one above the other and that have a refrigerant passage 63b formed therein, and a plurality of air that flows between adjacent flat tubes 63 are provided. And a plurality of fins 64 partitioned into the ventilation path. The flat tube 63 is divided into a plurality of heat exchange units 60A to 60G, and each of the heat exchange units 60A to 60G is a main heat exchange unit 61A to 61G and a main position at a different vertical position from the main heat exchange units 61A to 61G. Sub heat exchange units 62A to 62G connected in series to the heat exchange units 61A to 61G. And the 1st main heat exchange part 61A which comprises the 1st heat exchange part 60A containing the lowermost flat tube 63A among several heat exchange parts 60A-60G is arrange | positioned so that the lowermost flat pipe 63A may be included. ing.

  For this reason, in the structure of this modification, the time required for melting the frost adhering to the heat exchange part 60A of the lowest stage at the time of a defrost operation can be shortened similarly to the said embodiment.

  In addition, here, all of the heat exchange units 60B to 60G other than the first heat exchange unit 60A are arranged above the first heat exchange unit 60A. In the first heat exchange unit 60A, the first main heat exchange unit 61A is disposed below the first sub heat exchange unit 62A.

  In the configuration of the present modification, focusing on the first heat exchange unit 60A, during heating operation (used as a refrigerant evaporator), as shown in FIG. 13, the gas-liquid two-phase refrigerant is converted into the first sub heat exchange unit. The refrigerant in the gas-liquid two-phase state that flows into 62A and flows into the first sub heat exchange unit 62A is a first main heat exchange unit positioned below the first sub heat exchange unit 62A and the first sub heat exchange unit 62A. It passes through 61A in order, is heated, and flows out from 60A of 1st heat exchange parts. Further, during the defrosting operation (used as a radiator radiator), as shown in FIG. 14, the gaseous refrigerant flows into the first main heat exchanging part 61A and into the first main heat exchanging part 61A. The refrigerant passes through the first main heat exchanging part 61A and the first sub heat exchanging part 62A located above the first main heat exchanging part 61A in order, is cooled, and flows out of the first heat exchanging part 60A. Become.

  In the above configuration, since the first main heat exchanging part 61A is disposed below the first sub heat exchanging part 62A, the heating operation (refrigerant) is performed as in the above embodiment. As shown in FIG. 13, the first heat exchanging part 60A is disposed below the first sub heat exchanging part 62A after the refrigerant has passed through the first sub heat exchanging part 62A. It functions as a so-called downflow type evaporator that passes through the 1 main heat exchange section 61A. For this reason, also in the first heat exchanging part 60A of the present modification, the refrigerant is directed downward from the flat pipe 63 constituting the first sub heat exchanging part 62A to the flat pipe 63 constituting the first main heat exchanging part 61A. Since the refrigerant is diverted when it is sent, there is a risk of refrigerant drift. At this time, if the ratio of the number of the flat tubes 63 constituting the first main heat exchange portion 61A to the number of the flat tubes 63 constituting the first sub heat exchange portion 62A is increased, the risk of refrigerant drift increases. .

  Therefore, here, the ratio of the number (two) of the flat tubes 63 constituting the first main heat exchange portion 61A to the number (two) of the flat tubes 63 constituting the first sub heat exchange portion 62A (= 2 / 2 = 1.0), the flat tubes constituting the main heat exchange portions 61A to 61G with respect to the number of flat tubes (3 to 6) constituting the sub heat exchange portions 62B to 62G in the other heat exchange portions 60B to 60G It is set to be smaller than the ratio of 63 numbers (6 to 12) (= 7/4 to 12/5 = 1.8 to 2.4). The ratio of the number of flat tubes 63 constituting the first main heat exchange portion 61A to the number of flat tubes 63 constituting the first sub heat exchange portion 62A is not limited to 1.0, but is 0. It is preferable to be within the range of .5 to 1.5. Further, the ratio of the number of flat tubes 63 constituting the other main heat exchange portions 61B to 61G to the number of flat tubes 63 constituting the other sub heat exchange portions 62B to 62G is limited to 1.8 to 2.4. Although it is not performed, it is preferable to set it within the range of 1.7 to 3.0.

  Thereby, here, similarly to the above-described embodiment, during the heating operation (used as a refrigerant evaporator), the flat tube 63 constituting the first main heat exchange unit 61A from the flat tube 63 constituting the first sub heat exchange unit 62A is used. When the refrigerant is sent downward to the pipe 63, it is possible to suppress the drift of the refrigerant accompanying the flow of the refrigerant.

<B>
In the said embodiment and modification <A>, although this invention was applied with respect to the outdoor heat exchanger 11 which has six or seven heat exchange parts, it is not limited to this, The number of heat exchange parts is There may be fewer than six or more than seven.

  In addition, the number of flat tubes 63 constituting each heat exchange unit 60A to 60G and how to divide the number of main heat exchange units 61A to 61G and sub heat exchange units 62A to 62G in each heat exchange unit 60A to 60G The present invention is not limited to the embodiment and the modified example <A>.

  In the above embodiment and the modified example <A>, the present invention is applied to the outdoor heat exchanger 11 provided in the top-blowing outdoor unit 2, but the outdoor unit provided in another type of outdoor unit is used. The present invention may be applied to a heat exchanger.

  The present invention includes a plurality of flat tubes arranged vertically and having a refrigerant passage formed therein, and a plurality of fins that are divided into a plurality of ventilation paths through which air flows between adjacent flat tubes. Widely applicable to exchangers.

11 Outdoor heat exchanger (heat exchanger)
60A-60G heat exchange part 60A first heat exchange part 61A-61G main heat exchange part 61A first main heat exchange part 61AU first upper main heat exchange part 61AL first lower main heat exchange part 62A-62G sub heat exchange part 62A 1st sub heat exchange part 62AU 1st upper sub heat exchange part 62AL 1st lower sub heat exchange part 63 Flat tube 63b Passage 64 Fin

JP 2012-163313 A

  The present invention relates to a heat exchanger, in particular, a plurality of flat tubes arranged vertically and having a refrigerant passage formed therein, and a plurality of air passages partitioned into air between adjacent flat tubes. And a heat exchanger having fins.

  Conventionally, as a heat exchanger housed in an outdoor unit (heat exchange unit) of an air conditioner, a plurality of flat tubes arranged vertically and a plurality of ventilation paths through which air flows between adjacent flat tubes In some cases, a heat exchanger having a plurality of fins is employed. And as such a heat exchanger, as shown, for example in patent documents 1 (Unexamined-Japanese-Patent No. 2012-163313), a plurality of flat tubes are divided into a plurality of heat exchanging parts arranged up and down, Some heat exchange parts are formed to have a main heat exchange part and a sub heat exchange part connected in series to the main heat exchange part below the main heat exchange part.

  The conventional heat exchanger may be employed in an air conditioner that switches between heating operation and defrosting operation. Here, when the air conditioner performs the heating operation, the conventional heat exchanger is used as an evaporator of the refrigerant, and when the air conditioner performs the defrosting operation, the conventional heat exchanger is Used as a refrigerant radiator. Specifically, when the conventional heat exchanger is used as a refrigerant evaporator, the refrigerant in a gas-liquid two-phase state branches and flows into the sub heat exchange units constituting each heat exchange unit, The refrigerant in the gas-liquid two-phase state that has flowed into the sub heat exchange section passes through the sub heat exchange section and the main heat exchange section in this order and is heated, and flows out from each heat exchange section to join. When the conventional heat exchanger is used as a refrigerant radiator, the gas refrigerant branches and flows into the main heat exchange section of each heat exchange section, and flows into the main heat exchange section. The refrigerant in the state passes through the main heat exchange unit and the sub heat exchange unit in order and is cooled, and flows out from each heat exchange unit and joins.

  However, in the air conditioner employing the above-described conventional heat exchanger, the time required for melting the frost adhering to the heat exchanging portion constituting the lowermost heat exchanging portion during the defrosting operation is lower than the lowermost step. It tends to be longer than the time required to melt the frost attached to the heat exchange part on the upper stage side than the heat exchange part. For this reason, even after the defrosting operation, frost melting residue may occur in the lowermost heat exchanging part and the defrosting may be insufficient, and frost remaining unmelted in the lowermost heat exchanging part may occur. In order to suppress this, it is necessary to lengthen the time of the defrosting operation.

  An object of the present invention is to provide a plurality of flat tubes arranged vertically and having a refrigerant passage formed therein, and a plurality of fins partitioned into a plurality of ventilation paths through which air flows between adjacent flat tubes. When the heat exchanger is used in an air conditioner that switches between heating operation and defrosting operation, the time required to melt the frost adhering to the lowermost heat exchange part during the defrosting operation is To shorten it.

The heat exchanger according to the first aspect includes a plurality of flat tubes arranged vertically and having a refrigerant passage formed therein, and a plurality of air passages that partition between adjacent flat tubes into a plurality of ventilation paths. And fins. The flat tube is divided into a plurality of heat exchange sections, and each heat exchange section is connected to the main heat exchange section connected to the gas side inlet / outlet communication space, and the main heat exchange section at a different vertical position from the main heat exchange section. And a sub heat exchange section connected in series and connected to the liquid side inlet / outlet communication space . And here, let the heat exchange part containing the lowest flat tube among heat exchange parts be the 1st heat exchange part, and the main heat exchange part and sub heat exchange part which constitute the 1st heat exchange part are the 1st main heat exchange. If it is set as an exchange part and a 1st sub heat exchange part, the 1st main heat exchange part is arrange | positioned so that the lowermost flat tube may be included.

  First, when the conventional heat exchanger is used in an air conditioner that switches between heating operation and defrosting operation, it is necessary to melt the frost adhering to the lowest heat exchange part during the defrosting operation. The reason why the long time is likely to be longer than the time required to melt the frost attached to the heat exchange part on the upper stage side than the heat exchange part on the lowermost stage will be described.

  In the conventional heat exchanger, a plurality of flat tubes are divided into a plurality of heat exchanging portions arranged in the vertical direction, and each heat exchanging portion has a main heat exchanging portion below the main heat exchanging portion and the main heat exchanging portion. And a sub heat exchange section connected in series to the section. For this reason, in the said conventional heat exchanger, the sub heat exchange part which comprises the lowest heat exchange part among heat exchange parts is arrange | positioned so that a flat tube of the lowest stage may be included.

  In this conventional configuration, when switching from heating operation (used as a refrigerant evaporator) to defrosting operation (used as a refrigerant radiator), a liquid state is placed in the lowermost sub heat exchange section including the lowermost flat tube. The refrigerant is easy to accumulate. Then, when the defrosting operation is performed in such a state, the refrigerant in the gas state first flows into the lowermost main heat exchange part, and then flows into the lowermost sub heat exchange part. It takes time to evaporate the liquid refrigerant accumulated in the sub heat exchange section. That is, in the configuration of the conventional heat exchanger, the lowermost sub heat exchange part including the lowermost flat tube during the defrosting operation is located on the downstream side of the refrigerant flow. It is presumed that this is one of the causes that the time required to melt the frost adhering to the heat exchange part becomes long.

  In addition, in this configuration, when the refrigerant in the gas state branches during the defrosting operation and flows into the main heat exchange part of each heat exchange part, the refrigerant is affected by the liquid head of the refrigerant and the heat exchange part on the upper stage side. In comparison, the flow rate of the refrigerant in the gas state flowing into the lowermost heat exchanging portion is reduced, and the time required for melting the frost attached to the lowermost heat exchanging portion is lengthened. Since the degree of the liquid head is affected by the height position of the flat tube included in the sub heat exchange unit constituting the heat exchange unit, the lowermost sub heat exchange unit includes the lowermost flat tube. And the liquid head of a refrigerant | coolant is large and the flow volume of the refrigerant | coolant of the gas state which flows in at the time of a defrost operation further decreases. That is, in the configuration of the conventional heat exchanger described above, the flow rate of the refrigerant in the gas state flowing into the lowermost heat exchanging section by the refrigerant liquid head during the defrosting operation is reduced, so that the lowermost heat exchange is performed during the defrosting operation. It is estimated that this is one of the causes that the time required to melt the frost attached to the part becomes longer.

  Further, in this conventional configuration, since the lower end portion of the fin close to the lowermost flat tube is in contact with the drain pan, heat is easily generated from the lowermost sub heat exchange portion including the lowermost flat tube to the drain pan. . And, when the defrosting operation is performed in such a state, the heat in the lowermost heat exchanging portion is less likely to rise than the upper heat exchanging portion due to heat radiation from the lowermost sub heat exchanging portion to the drain pan. The time required to melt the frost adhering to the lowermost heat exchanging portion is lengthened. That is, in the configuration of the conventional heat exchanger described above, the heat radiation from the lowermost sub heat exchange part including the lowermost flat tube to the drain pan melts the frost attached to the lowermost heat exchange part during the defrosting operation. It is presumed that this is one of the causes of the long time required for this.

  As described above, the conventional heat exchanger is employed in an air conditioner that switches between heating operation and defrosting operation because the lowermost sub heat exchange section includes the lowermost flat tube. In this case, the time required to melt the frost attached to the lowermost heat exchange part is longer than the time required to melt the frost attached to the upper heat exchange part than the lowermost heat exchange part. Is also estimated to be longer.

  Therefore, here, unlike the conventional heat exchanger, as described above, the first main heat exchanging part constituting the first heat exchanging part including the lowermost flat tube among the heat exchanging parts is the lowermost stage. It arrange | positions so that a flat tube may be included.

  And when the heat exchanger which has this structure is employ | adopted for the air conditioning apparatus which switches heating operation and defrost operation, when it pays attention to a 1st heat exchange part, heating operation (uses it as an evaporator of a refrigerant | coolant). Sometimes the gas-liquid two-phase refrigerant flows into the first sub heat exchange section, and the gas-liquid two-phase refrigerant flowing into the first sub heat exchange section is the first sub heat exchange section, the lowermost flat tube The first main heat exchanging part including the heat is passed through and heated and flows out of the first heat exchanging part. Further, during the defrosting operation (used as a refrigerant radiator), the gaseous refrigerant flows into the first main heat exchange section, and the gaseous refrigerant flowing into the first main heat exchange section is the lowermost flat tube. The first main heat exchange part including the first heat exchange part and the first sub heat exchange part are passed through in order to be cooled and flow out of the first heat exchange part. That is, here, at the time of the defrosting operation, the first main heat exchange unit including the lowermost flat tube is positioned on the upstream side of the refrigerant flow. Therefore, here, the refrigerant in the gas state is caused to flow into the first main heat exchange section including the lowermost flat tube, and the liquid refrigerant accumulated in the first sub heat exchange section at the lowermost stage is actively heated. As well as evaporating, it becomes possible to quickly increase the temperature in the first heat exchange section at the lowermost stage, which makes it possible to reduce the temperature at the lowermost stage during the defrosting operation as compared with the case where the conventional heat exchanger is employed. The time required to melt the frost adhering to the heat exchange part can be shortened.

  Thus, here, by adopting the heat exchanger having the above-described configuration in an air conditioner that switches between heating operation and defrosting operation, frost adhering to the lowermost heat exchange section during the defrosting operation The time required to melt the can be shortened.

  In the heat exchanger according to the second aspect, in the heat exchanger according to the first aspect, all the heat exchange parts other than the first heat exchange part are arranged above the first heat exchange part. And the 1st main heat exchange part is arrange | positioned under the 1st sub heat exchange part at the 1st heat exchange part.

  When the heat exchanger having this configuration is employed in an air conditioner that switches between heating operation and defrosting operation, paying attention to the first heat exchange unit, during heating operation (used as a refrigerant evaporator), The gas-liquid two-phase refrigerant flows into the first sub heat exchange unit, and the gas-liquid two-phase refrigerant that flows into the first sub heat exchange unit flows into the first sub heat exchange unit and the first sub heat exchange unit. The first main heat exchanging part located below is passed through and heated, and flows out of the first heat exchanging part. Further, during the defrosting operation (used as a refrigerant radiator), the gaseous refrigerant flows into the first main heat exchange unit, and the gaseous refrigerant that has flowed into the first main heat exchange unit undergoes the first main heat exchange. And the first sub heat exchanging part located above the first main heat exchanging part are cooled in this order and flow out of the first heat exchanging part.

  The heat exchanger according to the third aspect is the heat exchanger according to the second aspect, wherein the number of flat tubes constituting the first main heat exchange unit is equal to the number of flat tubes constituting the first sub heat exchange unit. The ratio is set to be smaller than the ratio of the number of flat tubes constituting the main heat exchange unit to the number of flat tubes constituting the sub heat exchange unit in the other heat exchange unit.

  As described above, the heat exchanger according to the second aspect includes the first heat exchange part in which the first main heat exchange part is disposed below the first sub heat exchange part. For this reason, when the heat exchanger according to the second aspect is employed in an air conditioner that switches between heating operation and defrosting operation, the first heat is generated during the heating operation (used as a refrigerant evaporator). The exchange unit functions as a so-called downflow type evaporator in which the refrigerant passes through the first main heat exchange unit disposed below the first sub heat exchange unit after passing through the first sub heat exchange unit. Become. Here, in a downflow type evaporator, when a fluid in a gas-liquid two-phase state is sent downward and accompanied by a fluid diversion, fluid drift tends to occur. For this reason, also in the 1st heat exchanging part, when a refrigerant is sent from the flat tube which constitutes the 1st sub heat exchanging part to the flat tube which constitutes the 1st main heat exchanging part downward, it is accompanied by a branch of refrigerant. There is a risk of refrigerant drift. At this time, if the ratio of the number of flat tubes constituting the first main heat exchange portion to the number of flat tubes constituting the first sub heat exchange portion is increased, the risk of refrigerant drift increases.

  Therefore, here, as described above, for the first heat exchange part, the ratio of the number of flat tubes constituting the main heat exchange part to the number of flat pipes constituting the sub heat exchange part is determined as another heat exchange part. It is set to be smaller.

  Thereby, here, at the time of heating operation (used as an evaporator of the refrigerant), when the refrigerant is sent downward from the flat tube constituting the first sub heat exchange unit to the flat tube constituting the first main heat exchange unit In addition, it is possible to suppress the refrigerant drift due to the refrigerant split.

  In the heat exchanger according to the fourth aspect, in the heat exchanger according to the first aspect, all the heat exchange parts other than the first heat exchange part are arranged above the first heat exchange part. The first sub heat exchange section includes a first upper sub heat exchange section and a first lower sub heat exchange section below the first upper sub heat exchange section. In addition, the first main heat exchanging unit includes a first upper main heat exchanging unit connected to the first upper sub heat exchanging unit above the first upper sub heat exchanging unit and a lower portion of the first lower sub heat exchanging unit. And a first lower main heat exchange section connected to the first lower sub heat exchange section.

  When the heat exchanger having this configuration is employed in an air conditioner that switches between heating operation and defrosting operation, paying attention to the first heat exchange unit, during heating operation (used as a refrigerant evaporator), The gas-liquid two-phase refrigerant flows into the first upper sub heat exchange unit and the first lower sub heat exchange unit. The refrigerant in the gas-liquid two-phase state that has flowed into the first upper sub heat exchange section is in the order of the first upper sub heat exchange section and the first upper main heat exchange section located above the first upper sub heat exchange section. It passes through and is heated and flows out of the first heat exchange section. The refrigerant in the gas-liquid two-phase state that has flowed into the first lower sub heat exchange unit is a first lower main heat exchange unit located below the first lower sub heat exchange unit and the first lower sub heat exchange unit. Are passed through in this order and heated to flow out of the first heat exchange section. Further, during the defrosting operation (used as a refrigerant radiator), the gaseous refrigerant flows into the first upper main heat exchange unit and the first lower main heat exchange unit. The gas refrigerant flowing into the first upper main heat exchange section passes through the first upper main heat exchange section and the first upper sub heat exchange section located below the first upper main heat exchange section in this order. It is cooled and flows out of the first heat exchange part. The refrigerant in the gas state that has flowed into the first lower main heat exchange section passes through the first lower main heat exchange section and the first lower sub heat exchange section located above the first lower main heat exchange section in this order. Then, it is cooled and flows out of the first heat exchange section.

  A heat exchanger according to a fifth aspect is the heat exchanger according to the fourth aspect, wherein the flats constituting the first lower main heat exchange part with respect to the number of flat tubes constituting the first lower sub heat exchange part are provided. The ratio of the number of tubes is set to be smaller than the ratio of the number of flat tubes constituting the first upper main heat exchange unit to the number of flat tubes constituting the first upper sub heat exchange unit.

  In the heat exchanger according to the fourth aspect, as described above, the first upper sub heat exchange unit is disposed below the first upper main heat exchange unit, and the first lower sub heat exchange unit is below. 1st lower main heat exchange part has the 1st heat exchange part arranged. For this reason, when the heat exchanger according to the fourth aspect is employed in an air conditioner that switches between heating operation and defrosting operation, the first heat is generated during the heating operation (used as a refrigerant evaporator). The first lower sub heat exchange part and the first lower main heat exchange part among the exchange parts are disposed below the first lower sub heat exchange part after the refrigerant passes through the first lower sub heat exchange part. In addition, it functions as a so-called downflow type evaporator that passes through the first lower main heat exchange section. Here, in a downflow type evaporator, when a fluid in a gas-liquid two-phase state is sent downward and accompanied by a fluid diversion, fluid drift tends to occur. Therefore, also in the first lower sub heat exchange section and the first lower main heat exchange section, the flat pipe constituting the first lower main heat exchange section from the flat pipe constituting the first lower sub heat exchange section. When the refrigerant is sent downward, the refrigerant is diverted, and there is a possibility that the refrigerant drifts. At this time, if the ratio of the number of flat tubes constituting the first lower main heat exchange portion to the number of flat tubes constituting the first lower sub heat exchange portion is increased, there is a high risk of refrigerant drift. .

  Therefore, here, as described above, for the first heat exchange part, the number of flat tubes constituting the first lower main heat exchange part with respect to the number of flat pipes constituting the first lower sub heat exchange part. The ratio is set to be smaller than the ratio of the number of flat tubes constituting the first upper main heat exchange portion to the number of flat tubes constituting the first upper sub heat exchange portion.

  Thereby, here, at the time of heating operation (used as an evaporator of the refrigerant), the refrigerant is moved downward from the flat tube constituting the first lower sub heat exchange portion to the flat tube constituting the first lower main heat exchange portion. When sending the refrigerant, it is possible to suppress the drift of the refrigerant accompanying the flow of the refrigerant.

  A heat exchanger according to a sixth aspect is the heat exchanger according to any one of the first to fifth aspects, wherein the heat exchange units are arranged side by side, and heat other than the first heat exchange unit The sub heat exchange part is arrange | positioned under the main heat exchange part at the exchange part.

  When the heat exchanger having this configuration is adopted in an air conditioner that performs switching between heating operation and defrosting operation, when attention is paid to the heat exchange unit other than the first heat exchange unit, the heating operation (refrigerant evaporator) The gas-liquid two-phase refrigerant flows into the sub heat exchange section, and the gas-liquid two-phase refrigerant flowing into the sub heat exchange section is located above the sub heat exchange section and the sub heat exchange section. The main heat exchanging parts that pass through are heated by passing through the heat exchanging parts. In addition, during the defrosting operation (used as a radiator radiator), the gaseous refrigerant flows into the main heat exchange unit, and the gaseous refrigerant that flows into the main heat exchange unit includes the main heat exchange unit and the main heat exchange unit. It passes through the sub heat exchanging part located in the lower part in order, is cooled, and flows out of the heat exchanging part.

  As described in the above description, according to the present invention, the first main heat exchanging portion constituting the first heat exchanging portion including the lowermost flat tube is arranged to include the lowermost flat tube. By adopting a heat exchanger with an air conditioner that switches between heating operation and defrosting operation, the time required to melt the frost adhering to the lowest heat exchange part during the defrosting operation is shortened be able to.

It is a schematic block diagram of the air conditioning apparatus by which the outdoor heat exchanger as a heat exchanger concerning one Embodiment of this invention was employ | adopted. It is an external appearance perspective view of an outdoor unit. It is a front view of an outdoor unit (shown excluding refrigerant circuit components other than the outdoor heat exchanger). It is a schematic perspective view of an outdoor heat exchanger. It is a partial expansion perspective view of the heat exchange part of FIG. It is a schematic block diagram of an outdoor heat exchanger. It is the figure which tabulated schematic structure of the outdoor heat exchanger. FIG. 7 is an enlarged view of the vicinity of the lowermost heat exchange section (first heat exchange section) in FIG. 6 (the refrigerant flow during heating operation is illustrated). FIG. 7 is an enlarged view of the lowermost heat exchange section (first heat exchange section) in FIG. 6 (the refrigerant flow during the defrosting operation is illustrated). It is a schematic perspective view of the outdoor heat exchanger as a heat exchanger concerning a modification. It is a schematic block diagram of the outdoor heat exchanger concerning a modification. It is the figure which tabulated schematic structure of the outdoor heat exchanger concerning a modification. FIG. 12 is an enlarged view of the vicinity of the lowermost heat exchange section (first heat exchange section) in FIG. 11 (the refrigerant flow during heating operation is illustrated). FIG. 12 is an enlarged view of the vicinity of the lowermost heat exchange section (first heat exchange section) in FIG. 11 (the refrigerant flow during the defrosting operation is illustrated).

  Hereinafter, an embodiment of a heat exchanger concerning the present invention and its modification are described based on a drawing. In addition, the specific structure of the heat exchanger concerning this invention is not restricted to the following embodiment and its modification, It can change in the range which does not deviate from the summary of invention.

(1) Configuration of Air Conditioner FIG. 1 is a schematic configuration diagram of an air conditioner 1 in which an outdoor heat exchanger 11 as a heat exchanger according to an embodiment of the present invention is employed.

  The air conditioner 1 is a device capable of cooling and heating a room such as a building by performing a vapor compression refrigeration cycle. The air conditioner 1 mainly includes an outdoor unit 2, indoor units 3a and 3b, a liquid refrigerant communication tube 4 and a gas refrigerant communication tube 5 that connect the outdoor unit 2 and the indoor units 3a and 3b, an outdoor unit 2 and And a control unit 23 that controls the constituent devices of the indoor units 3a and 3b. The vapor compression refrigerant circuit 6 of the air conditioner 1 is configured by connecting the outdoor unit 2 and the indoor units 3 a and 3 b via the refrigerant communication tubes 4 and 5.

  The outdoor unit 2 is installed outdoors (on the roof of a building, in the vicinity of the wall surface of the building, etc.) and constitutes a part of the refrigerant circuit 6. The outdoor unit 2 mainly includes an accumulator 7, a compressor 8, a four-way switching valve 10, an outdoor heat exchanger 11, an outdoor expansion valve 12 as an expansion mechanism, a liquid side shut-off valve 13, and a gas side shut-off valve. 14 and an outdoor fan 15. Each device and the valve are connected by refrigerant pipes 16 to 22.

  The indoor units 3 a and 3 b are installed indoors (such as a living room or a ceiling space) and constitute a part of the refrigerant circuit 6. The indoor unit 3a mainly has an indoor expansion valve 31a, an indoor heat exchanger 32a, and an indoor fan 33a. The indoor unit 3b mainly includes an indoor expansion valve 31b as an expansion mechanism, an indoor heat exchanger 32b, and an indoor fan 33b.

  The refrigerant communication pipes 4 and 5 are refrigerant pipes that are constructed on site when the air conditioner 1 is installed at an installation location such as a building. One end of the liquid refrigerant communication tube 4 is connected to the liquid side closing valve 13 of the indoor unit 2, and the other end of the liquid refrigerant communication tube 4 is connected to the liquid side ends of the indoor expansion valves 31a and 31b of the indoor units 3a and 3b. Has been. One end of the gas refrigerant communication pipe 5 is connected to the gas side shut-off valve 14 of the indoor unit 2, and the other end of the gas refrigerant communication pipe 5 is connected to the gas side ends of the indoor heat exchangers 32a and 32b of the indoor units 3a and 3b. It is connected.

  The control unit 23 is configured by communication connection of control boards and the like (not shown) provided in the outdoor unit 2 and the indoor units 3a and 3b. In FIG. 1, for the sake of convenience, the outdoor unit 2 and the indoor units 3a and 3b are illustrated at positions away from each other. The control unit 23 controls the components 8, 10, 12, 15, 31a, 31b, 33a, 33b of the air conditioner 1 (here, the outdoor unit 2 and the indoor units 3a, 3b), that is, the air conditioner 1 The whole operation control is performed.

(2) Operation | movement of an air conditioning apparatus Next, operation | movement of the air conditioning apparatus 1 is demonstrated using FIG. In the air conditioner 1, the cooling operation in which the refrigerant is circulated in the order of the compressor 8, the outdoor heat exchanger 11, the outdoor expansion valve 12, the indoor expansion valves 31a and 31b, and the indoor heat exchangers 32a and 32b, the compressor 8, the indoor Heating operation is performed in which the refrigerant is circulated in the order of the heat exchangers 32a and 32b, the indoor expansion valves 31a and 31b, the outdoor expansion valve 12, and the outdoor heat exchanger 11. Moreover, at the time of heating operation, the defrost operation for melting the frost adhering to the outdoor heat exchanger 11 is performed. Here, similarly to the cooling operation, the reverse cycle defrosting operation in which the refrigerant is circulated in the order of the compressor 8, the outdoor heat exchanger 11, the outdoor expansion valve 12, the indoor expansion valves 31a and 31b, and the indoor heat exchangers 32a and 32b. Is done. The cooling operation, the heating operation, and the defrosting operation are performed by the control unit 23.

  During the cooling operation, the four-way switching valve 10 is switched to the outdoor heat dissipation state (the state shown by the solid line in FIG. 1). In the refrigerant circuit 6, the low-pressure gas refrigerant in the refrigeration cycle is sucked into the compressor 8 and is compressed until it reaches the high pressure in the refrigeration cycle, and then discharged. The high-pressure gas refrigerant discharged from the compressor 8 is sent to the outdoor heat exchanger 11 through the four-way switching valve 10. The high-pressure gas refrigerant sent to the outdoor heat exchanger 11 dissipates heat by exchanging heat with outdoor air supplied as a cooling source by the outdoor fan 15 in the outdoor heat exchanger 11 that functions as a refrigerant radiator. Become a high-pressure liquid refrigerant. The high-pressure liquid refrigerant radiated in the outdoor heat exchanger 11 is sent to the indoor expansion valves 31 a and 31 b through the outdoor expansion valve 12, the liquid-side closing valve 13, and the liquid refrigerant communication pipe 4. The refrigerant sent to the indoor expansion valves 31a and 31b is decompressed to the low pressure of the refrigeration cycle by the indoor expansion valves 31a and 31b, and becomes a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant decompressed by the indoor expansion valves 31a and 31b is sent to the indoor heat exchangers 32a and 32b. The low-pressure gas-liquid two-phase refrigerant sent to the indoor heat exchangers 32a and 32b exchanges heat with indoor air supplied as a heating source by the indoor fans 33a and 33b in the indoor heat exchangers 32a and 32b. Evaporate. As a result, the room air is cooled and then supplied to the room to cool the room. The low-pressure gas refrigerant evaporated in the indoor heat exchangers 32 a and 32 b is again sucked into the compressor 8 through the gas refrigerant communication pipe 5, the gas side closing valve 14, the four-way switching valve 10, and the accumulator 7.

  During the heating operation, the four-way selector valve 10 is switched to the outdoor evaporation state (the state indicated by the broken line in FIG. 1). In the refrigerant circuit 6, the low-pressure gas refrigerant in the refrigeration cycle is sucked into the compressor 8 and is compressed until it reaches the high pressure in the refrigeration cycle, and then discharged. The high-pressure gas refrigerant discharged from the compressor 8 is sent to the indoor heat exchangers 32 a and 32 b through the four-way switching valve 10, the gas side closing valve 14, and the gas refrigerant communication pipe 5. The high-pressure gas refrigerant sent to the indoor heat exchangers 32a and 32b dissipates heat by exchanging heat with indoor air supplied as a cooling source by the indoor fans 33a and 33b in the indoor heat exchangers 32a and 32b. Becomes a high-pressure liquid refrigerant. Thereby, indoor air is heated, and indoor heating is performed by being supplied indoors after that. The high-pressure liquid refrigerant radiated by the indoor heat exchangers 32 a and 32 b is sent to the outdoor expansion valve 12 through the indoor expansion valves 31 a and 31 b, the liquid refrigerant communication tube 4 and the liquid-side closing valve 13. The refrigerant sent to the outdoor expansion valve 12 is decompressed to the low pressure of the refrigeration cycle by the outdoor expansion valve 12, and becomes a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant decompressed by the outdoor expansion valve 12 is sent to the outdoor heat exchanger 11. The low-pressure gas-liquid two-phase refrigerant sent to the outdoor heat exchanger 11 exchanges heat with outdoor air supplied as a heating source by the outdoor fan 15 in the outdoor heat exchanger 11 that functions as a refrigerant evaporator. Go and evaporate into a low-pressure gas refrigerant. The low-pressure refrigerant evaporated in the outdoor heat exchanger 11 is again sucked into the compressor 8 through the four-way switching valve 10 and the accumulator 7.

  During the heating operation described above, when frost formation in the outdoor heat exchanger 11 is detected due to the refrigerant temperature in the outdoor heat exchanger 11 being lower than a predetermined temperature, that is, defrosting of the outdoor heat exchanger 11 is performed. When the conditions to start are reached, a defrosting operation is performed to melt frost attached to the outdoor heat exchanger 11.

  As in the cooling operation, the defrosting operation is performed by switching the four-way switching valve 22 to the outdoor heat radiation state (the state indicated by the solid line in FIG. 1) and causing the outdoor heat exchanger 11 to function as a refrigerant radiator. Is called. Thereby, the frost adhering to the outdoor heat exchanger 11 can be thawed. The defrosting operation is performed outdoors until the defrosting time set in consideration of the state of the heating operation before defrosting, or the temperature of the refrigerant in the outdoor heat exchanger 11 becomes higher than a predetermined temperature. This is performed until it is determined that the defrosting in the heat exchanger 11 is completed, and then the heating operation is resumed. In addition, since the flow of the refrigerant | coolant in the refrigerant circuit 10 at the time of a defrost operation is the same as that of a cooling operation, description is abbreviate | omitted here.

(3) Configuration of Outdoor Unit FIG. 2 is an external perspective view of the outdoor unit 2. FIG. 3 is a front view of the outdoor unit 2 (illustrated excluding refrigerant circuit components other than the outdoor heat exchanger 11). FIG. 4 is a schematic perspective view of the outdoor heat exchanger 11. FIG. 5 is a partially enlarged view of the heat exchange units 60A to 60F in FIG. FIG. 6 is a schematic configuration diagram of the outdoor heat exchanger 11. FIG. 7 is a table listing the schematic configuration of the outdoor heat exchanger 11. FIG. 8 is an enlarged view (the refrigerant flow during heating operation is illustrated) in the vicinity of the lowermost heat exchange section (first heat exchange section 60A) of FIG. FIG. 9 is an enlarged view (the refrigerant flow during the defrosting operation is illustrated) in the vicinity of the lowermost heat exchange section (first heat exchange section 60A) of FIG.

<Overall>
The outdoor unit 2 is a top blow type heat exchange unit that sucks air from the side surface of the casing 40 and blows air from the top surface of the casing 40. The outdoor unit 2 mainly includes a substantially rectangular parallelepiped box-shaped casing 40, an outdoor fan 15 as a blower, devices 7, 8, 11 such as a compressor and an outdoor heat exchanger, a four-way switching valve, an outdoor expansion valve, and the like. And refrigerant circuit components that constitute part of the refrigerant circuit 6 including the valves 10, 12 to 14, the refrigerant pipes 16 to 22, and the like. In the following description, “top”, “bottom”, “left”, “right”, “front”, “back”, “front”, and “back” are shown in FIG. 2 unless otherwise specified. The direction when the outdoor unit 2 to be viewed is viewed from the front (left oblique front side of the drawing) is meant.

  The casing 40 mainly includes a bottom frame 42 that spans a pair of installation legs 41 that extend in the left-right direction, a column 43 that extends vertically from a corner of the bottom frame 42, and a fan module 44 that is attached to the upper end of the column 43. And a front panel 45, and air inlets 40a, 40b, 40c are formed on the side surfaces (here, the rear surface and the left and right side surfaces), and an air outlet 40d is formed on the top surface.

  The bottom frame 42 forms the bottom surface of the casing 40, and the outdoor heat exchanger 11 is provided on the bottom frame 42. Here, the outdoor heat exchanger 11 is a substantially U-shaped heat exchanger in plan view facing the back surface and both left and right side surfaces of the casing 40, and substantially forms the back surface and both left and right side surfaces of the casing 40. . The bottom frame 42 is in contact with the lower end portion of the outdoor heat exchanger 11 and functions as a drain pan that receives drain water generated in the outdoor heat exchanger 11 during cooling operation or defrosting operation.

  A fan module 44 is provided on the upper side of the outdoor heat exchanger 11, and forms a portion above the front and rear surfaces of the casing 40 and the right and left both-side support columns 43 and the top surface of the casing 40. . Here, the fan module 44 is an assembly in which the outdoor fan 15 is accommodated in a substantially rectangular parallelepiped box having an upper surface and a lower surface opened. The opening on the top surface of the fan module 44 is an air outlet 40d, and an air outlet grill 46 is provided at the air outlet 40d. The outdoor fan 15 is disposed in the casing 40 so as to face the air outlet 40d, and is a blower that takes air into the casing 40 from the suction ports 40a, 40b, and 40c and discharges it from the air outlet 40d.

  The front panel 45 is spanned between the support columns 43 on the front side, and forms the front surface of the casing 40.

  In the casing 40, refrigerant circuit components (the accumulator 7 and the compressor 8 are shown in FIG. 2) other than the outdoor fan 15 and the outdoor heat exchanger 11 are also accommodated. Here, the compressor 8 and the accumulator 7 are provided on the bottom frame 42.

  As described above, the outdoor unit 2 includes the casing 40 in which the air suction ports 40a, 40b, and 40c are formed on the side surfaces (here, the rear surface and the left and right side surfaces), and the air outlet 40d is formed on the top surface. It has the outdoor fan 15 arrange | positioned facing the blower outlet 40d in the inside, and the outdoor heat exchanger 11 arrange | positioned in the casing 40 under the outdoor fan 15 inside.

<Outdoor heat exchanger>
The outdoor heat exchanger 11 is a heat exchanger that performs heat exchange between the refrigerant and the outdoor air, and mainly includes a first header collecting pipe 80, a second header collecting pipe 90, a plurality of flat tubes 63, and a plurality of flat tubes 63. And fins 64. Here, all of the first header collecting pipe 80, the second header collecting pipe 90, the flat pipe 63, and the fins 64 are formed of aluminum or an aluminum alloy, and are joined to each other by brazing or the like.

  Each of the first header collecting pipe 80 and the second header collecting pipe 90 is a vertically long hollow cylindrical member with its upper end and lower end closed. The first header collecting pipe 80 is erected on one end side of the outdoor heat exchanger 11 (here, the left front end side in FIG. 4 or the left end side in FIG. 6), and the second header collecting pipe 90 is It is erected on the other end side of the outdoor heat exchanger 11 (here, the right front end side in FIG. 4 or the right end side in FIG. 6).

  The flat tube 63 is a flat multi-hole tube having a flat surface portion 63a facing the vertical direction serving as a heat transfer surface, and a large number of small passages 63b through which a refrigerant formed inside flows. A plurality of flat tubes 63 are arranged vertically, and both ends thereof are connected to the first header collecting tube 80 and the second header collecting tube 90. The fins 64 are partitioned into a plurality of ventilation paths through which air flows between adjacent flat tubes 63, and a plurality of cutouts 64a extending horizontally are formed so that the plurality of flat tubes 63 can be inserted. . The shape of the notch 64 a of the fin 64 substantially matches the outer shape of the cross section of the flat tube 63.

  In the outdoor heat exchanger 11, the plurality of flat tubes 63 are divided into a plurality of (here, six) heat exchange units 60A to 60F arranged vertically. Specifically, here, in order from the bottom to the top, the first heat exchange unit 60A, the second heat exchange unit 60B,..., The fifth heat exchange unit 60E, and the sixth heat, which are the lowest heat exchange units. An exchange part 60F is formed. The first heat exchanging part 60A has 21 flat tubes 63 including a flat tube 63A at the lowest stage. The second heat exchanging unit 60B has 18 flat tubes 63. The third heat exchanging part 60 </ b> C has 15 flat tubes 63. The fourth heat exchanging unit 60D has 13 flat tubes 63. The fifth heat exchanging unit 60E has eleven flat tubes 63. The sixth heat exchanging unit 60F has nine flat tubes 63.

  The first header collecting pipe 80 is partitioned into upper and lower portions by a partition plate 81 to form entrance / exit communication spaces 82A to 82F corresponding to the heat exchange portions 60A to 60F. Further, each of the inlet / outlet communication spaces 82B to 82F excluding the first inlet / outlet communication space 82A corresponding to the first heat exchange section 60A is divided into two upper and lower portions by the partition plate 83, so that the upper gas side inlet / outlet communication space 84B. To 84F and lower liquid side inlet / outlet communication spaces 85B to 85F are formed. The first inlet / outlet communication space 82A corresponding to the first heat exchange section 60A is partitioned into two upper and lower parts by two partition plates 86, so that the first upper gas side inlet / outlet communication space 84AU and A first liquid side inlet / outlet communication space 85A and a first lower gas side inlet / outlet communication space 84AL are formed. Here, the first upper gas side inlet / outlet communication space 84AU and the first lower gas side inlet / outlet communication space 84AL are collectively referred to as a first gas side inlet / outlet communication space 84A.

  The second gas side inlet / outlet communication space 84B communicates with the top twelve of the flat tubes 63 that constitute the second heat exchange section 60B, and the second liquid side inlet / outlet communication space 85B includes the second heat exchange section 60B. The remaining six flat tubes 63 communicate with the remaining flat tubes 63. The third gas side inlet / outlet communication space 84C communicates with the top ten of the flat tubes 63 constituting the third heat exchange part 60C, and the third liquid side inlet / outlet communication space 85C constitutes the third heat exchange part 60C. The remaining five flat tubes 63 communicate with the remaining flat tubes 63. The fourth gas side inlet / outlet communication space 84D communicates with nine of the flat tubes 63 constituting the fourth heat exchange part 60D from above, and the fourth liquid side inlet / outlet communication space 85D constitutes the fourth heat exchange part 60D. The remaining four flat tubes 63 communicate with the remaining flat tubes 63. The fifth gas side inlet / outlet communication space 84E communicates with seven of the flat tubes 63 constituting the fifth heat exchange unit 60E from the top, and the fifth liquid side inlet / outlet communication space 85E constitutes the fifth heat exchange unit 60E. The remaining four flat tubes 63 communicate with the remaining flat tubes 63. The sixth gas side inlet / outlet communication space 84F communicates with the top six of the flat tubes 63 constituting the sixth heat exchange part 60F, and the sixth liquid side inlet / outlet communication space 85F constitutes the sixth heat exchange part 60F. The remaining three flat tubes 63 communicate with the remaining flat tubes 63. The first upper gas side inlet / outlet communication space 84AU communicates with twelve from the top among the flat tubes 63 constituting the first heat exchange section 60A, and the first lower gas side inlet / outlet communication space 84AL is the first heat exchange section. Of the flat tubes 63 constituting 60A, the lower one including the lowest flat tube 63A communicates with the bottom two, and the first liquid side inlet / outlet communication space 85A is the remaining 7 of the flat tubes 63 constituting the first heat exchange section 60A. Communicate with the book.

  Here, the flat tubes 63 communicating with the gas side inlet / outlet communication spaces 84A to 84F are referred to as main heat exchange portions 61A to 61F, and the flat tubes 63 connected to the liquid side inlet / outlet communication spaces 85A to 85F are sub heat exchange portions 62A to 62F. And That is, in the second inlet / outlet communication space 82B, the second gas side inlet / outlet communication space 84B communicates with twelve from the top of the flat tubes 63 constituting the second heat exchange section 60B (second main heat exchange section 61B), The second liquid side inlet / outlet communication space 85B communicates with the remaining six flat tubes 63 of the flat tube 63 constituting the second heat exchange portion 60B (second sub heat exchange portion 62B). In the third inlet / outlet communication space 82C, the third gas-side inlet / outlet communication space 84C communicates with the top ten of the flat tubes 63 constituting the third heat exchange section 60C (third main heat exchange section 61C), the third The liquid side inlet / outlet communication space 85C communicates with the remaining five flat tubes 63 of the flat tubes 63 constituting the third heat exchange portion 60C (third sub heat exchange portion 62C). In the fourth inlet / outlet communication space 82D, the fourth gas side inlet / outlet communication space 84D communicates with the top nine of the flat tubes 63 constituting the fourth heat exchange section 60D (fourth main heat exchange section 61D), the fourth. The liquid side inlet / outlet communication space 85D communicates with the remaining four flat tubes 63 of the flat tube 63 constituting the fourth heat exchange portion 60D (fourth sub heat exchange portion 62D). In the fifth inlet / outlet communication space 82E, the fifth gas side inlet / outlet communication space 84E communicates with the top seven of the flat tubes 63 constituting the fifth heat exchange section 60E (fifth main heat exchange section 61E), The liquid side inlet / outlet communication space 85E communicates with the remaining four flat tubes 63 of the flat tube 63 constituting the fifth heat exchange unit 60E (fifth sub heat exchange unit 62E). In the sixth inlet / outlet communication space 82F, the sixth gas side inlet / outlet communication space 84F communicates with the top six of the flat tubes 63 constituting the sixth heat exchange section 60F (sixth main heat exchange section 61F), sixth The liquid side inlet / outlet communication space 85F communicates with the remaining three flat tubes 63 of the flat tube 63 constituting the sixth heat exchanging portion 60F (sixth sub heat exchanging portion 62F). In the first inlet / outlet communication space 82A, the first upper gas side inlet / outlet communication space 84AU, which is one of the first gas side inlet / outlet communication spaces 84A, communicates with the top twelve of the flat tubes 63 constituting the first heat exchange section 60A. (The first upper main heat exchanging portion 61AU which is one of the first main heat exchanging portions 61A). In the first inlet / outlet communication space 82A, the first lower gas side inlet / outlet communication space 84AL, which is the other side of the first gas side inlet / outlet communication space 84A, has two flat pipes 63 constituting the first heat exchange section 60A from the bottom. It communicates with the book (the first lower main heat exchange section 61AL which is the other of the first main heat exchange sections 61A). Furthermore, in the first inlet / outlet communication space 82A, the first liquid side inlet / outlet communication space 85A communicates with the remaining seven flat tubes 63 constituting the first heat exchange section 60A (first sub heat exchange section 62A).

  Further, the first header collecting pipe 80 includes a liquid side diverting member 70 for diverting the refrigerant sent from the outdoor expansion valve 12 (see FIG. 1) during heating operation to the liquid side inlet / outlet communication spaces 85A to 85F, and for cooling. A gas side diverting member 75 that diverts and sends the refrigerant sent from the compressor 8 (see FIG. 1) during operation to the gas side inlet / outlet communication spaces 84A to 84F is connected.

  The liquid side diverting member 70 extends from the liquid side refrigerant diverter 71 connected to the refrigerant pipe 20 (see FIG. 1) and the liquid side refrigerant diverter 71 and is connected to the liquid side inlet / outlet communication spaces 85A to 85F. Liquid side refrigerant distribution pipes 72A to 72F. Here, the liquid side refrigerant distribution pipes 72A to 72F have capillary tubes, and those having a length and an inner diameter corresponding to the distribution ratio to the sub heat exchange parts 62A to 62F are used.

  The gas side branch member 75 extends from the gas side refrigerant branch mother pipe 76 connected to the refrigerant pipe 19 (see FIG. 1) and the gas side refrigerant branch mother pipe 76 and is connected to the gas side inlet / outlet communication spaces 84A to 84F. Gas side refrigerant branch branch pipes 77A to 77F. Here, since the first gas side inlet / outlet communication space 84A includes the first upper gas side inlet / outlet communication space 84AU and the first lower gas side inlet / outlet communication space 84AL, the gas side refrigerant branch main pipe 76 is provided. The first gas-side refrigerant branch branch tube 77A extending from the first pipe also has a first upper gas-side refrigerant branch branch tube 77AU and a first lower gas-side refrigerant branch branch tube 77AL.

  As for the 2nd header collection pipe 90, the internal space is divided up and down by the partition plate 91, and the folding | returning communication space 92A-92F corresponding to each heat exchange part 60A-60F is formed. The first folded communication space 92A corresponding to the first heat exchange section 60A is partitioned into two upper and lower parts by the partition plate 93, so that the upper first upper folded communication space 92AU and the lower first lower side are separated. A folded communication space 92AL is formed. As described above, the internal space of the second header collecting pipe 90 is not limited to the configuration that is only partitioned by the partition plates 91 and 93, but the refrigerant flow state in the second header collecting pipe 90 The structure by which the device for maintaining favorable was made may be sufficient.

  And each return | turnback communication space 92A-92F is connected to all the flat tubes 63 which comprise the corresponding heat exchange parts 60A-60F. That is, the second folded communication space 92B communicates with all of the 18 flat tubes 63 that constitute the second heat exchange section 60B. The third folded communication space 92C communicates with all of the 15 flat tubes 63 constituting the third heat exchange unit 60C. The fourth folded communication space 92D communicates with all of the 13 flat tubes 63 constituting the fourth heat exchange unit 60D. The fifth folded communication space 92E communicates with all the eleven flat tubes 63 constituting the fifth heat exchange unit 60E. The sixth folded communication space 92F communicates with all nine flat tubes 63 constituting the sixth heat exchange unit 60F. The first folded communication space 92A communicates with all of the 21 flat tubes 63 constituting the first heat exchange section 60A. Here, the first upper folded communication space 92AU, which is the upper portion of the first folded communication space 92A, communicates with the top 17 of the 21 flat tubes 63 constituting the first heat exchange section 60A. Further, the first lower folded communication space 92AL, which is the lower portion of the first folded communication space 92A, includes a lowermost flat tube 63A among the 21 flat tubes 63 constituting the first heat exchange section 60A. It communicates with four. Of the 17 flat tubes 63 communicating with the first upper folded communication space 92AU, the twelve flat tubes 63 from the top serve as the first upper main heat exchange portion 61AU, which is one of the first main heat exchange portions 61A. The remaining five flat tubes 63 constitute a first upper sub heat exchange portion 62AU that is an upper portion of the first sub heat exchange portion 62A. Of the four flat tubes 63 communicating with the first lower folded communication space 92AL, the two flat tubes 63 including the lowermost flat tube 63A are the other of the first main heat exchange portions 61A. The first lower main heat exchanging part 61AL is configured, and the remaining two flat tubes 63 configure the first lower sub heat exchanging part 62AL which is the lower part of the first sub heat exchanging part 62A. Yes.

  Thereby, each heat exchange part 60A-60F is the sub heat exchange part connected in series to main heat exchange part 61A-61F in the vertical position different from main heat exchange part 61A-61F and main heat exchange part 61A-61F. 62A-62F. That is, the second heat exchange unit 60B is positioned directly below the 12 flat tubes 63 constituting the second main heat exchange unit 61B communicating with the second gas side inlet / outlet communication space 84B and the second main heat exchange unit 61B. And the six flat tubes 63 constituting the second sub heat exchange section 62B communicating with the second liquid side inlet / outlet communication space 85B are connected in series through the second folded communication space 92B. Yes. The third heat exchange part 60C is located immediately below the ten flat tubes 63 constituting the third main heat exchange part 61C communicating with the third gas side inlet / outlet communication space 84C and the third main heat exchange part 61C. The five flat tubes 63 constituting the third sub heat exchange portion 62C communicating with the third liquid side inlet / outlet communication space 85C are connected in series through the third folded communication space 92C. The fourth heat exchange part 60D is located directly below the nine flat tubes 63 constituting the fourth main heat exchange part 61D communicating with the fourth gas side inlet / outlet communication space 84D and the fourth main heat exchange part 61D. The four flat tubes 63 constituting the fourth sub heat exchanging portion 62D communicating with the fourth liquid side inlet / outlet communication space 85D are connected in series through the fourth folded communication space 92D. The fifth heat exchanging part 60E is located immediately below the seven flat tubes 63 constituting the fifth main heat exchanging part 61E communicating with the fifth gas side inlet / outlet communication space 84E and the fifth main heat exchanging part 61E. The four flat tubes 63 constituting the fifth sub heat exchange section 62E communicating with the fifth liquid side inlet / outlet communication space 85E are connected in series through the fifth return communication space 92E. The sixth heat exchange part 60F is located directly below the six flat tubes 63 constituting the sixth main heat exchange part 61F communicating with the sixth gas side inlet / outlet communication space 84F and the sixth main heat exchange part 61F. The three flat tubes 63 constituting the sixth sub heat exchange part 62F communicating with the sixth liquid side inlet / outlet communication space 85F are connected in series through the sixth folded communication space 92F. The first heat exchange unit 60A includes fourteen flat tubes 63 constituting the first main heat exchange unit 61A communicating with the first gas side inlet / outlet communication space 84A and the first liquid side inlet / outlet communication space 85A. The seven flat tubes 63 constituting the sub heat exchange section 62A are connected in series through the first folded communication space 92A. Here, the first heat exchanging unit 60A has two upper and lower heat exchanging units 60AU and 60AL. The first upper heat exchange unit AU includes twelve flat tubes 63 constituting the first upper main heat exchange unit 61AU communicating with the first upper gas side inlet / outlet communication space 84AU, and directly below the first upper main heat exchange unit 61AU. The five flat tubes 63 constituting the first upper sub heat exchanging portion 62AU communicating with the first liquid side inlet / outlet communication space 85A are connected in series through the first upper folded communication space 92AU. have. The first lower heat exchange portion AL includes two flat tubes 63 including a lowermost flat tube 63A constituting the first lower main heat exchange portion 61AL communicating with the first lower gas side inlet / outlet communication space 84AL. Two flat tubes 63 that constitute the first lower sub heat exchange portion 62AL that is located immediately above the first lower main heat exchange portion 61AL and communicates with the first liquid side inlet / outlet communication space 85A. 1 It has the structure connected in series through the lower return communication space 92AL.

  Thus, here, a plurality of flat tubes 63 arranged vertically and having a refrigerant passage 63b formed therein, and a plurality of ventilation paths through which air flows between the adjacent flat tubes 63 are divided. And fins 64. The flat tube 63 is divided into a plurality of heat exchange units 60A to 60F. The heat exchange units 60A to 60F are main heat exchange units 61A to 61F and main positions at different vertical positions from the main heat exchange units 61A to 61F. And sub heat exchange units 62A to 62F connected in series to the heat exchange units 61A to 61F. And the 1st main heat exchange part 61A which comprises the 1st heat exchange part 60A containing the lowermost flat tube 63A among several heat exchange parts 60A-60F is arrange | positioned so that the lowermost flat pipe 63A may be included. ing.

  In addition, here, all of the heat exchange units 60B to 60F other than the first heat exchange unit 60A are arranged above the first heat exchange unit 60A. The first sub heat exchange unit 62A includes a first upper sub heat exchange unit 62AU and a first lower sub heat exchange unit 62AL below the first upper sub heat exchange unit 62AU. Moreover, the first main heat exchange unit 61A includes a first upper main heat exchange unit 61AU connected to the first upper sub heat exchange unit 62AU above the first upper sub heat exchange unit 62AU, and a first lower sub heat exchange. A first lower main heat exchange unit 61AL connected to the first lower sub heat exchange unit 62AL is provided below the exchange unit 62AL.

  In addition, here, the ratio of the number (two) of the flat tubes 63 constituting the first lower main heat exchange section 61AL to the number (two) of the flat tubes 63 constituting the first lower sub heat exchange section 62AL. (= 2/2 = 1.0) is the number of flat tubes 63 constituting the first upper main heat exchanging portion 61AU with respect to the number of flat tubes 63 constituting the first upper sub heat exchanging portion 62AU (five). 12) is set to be smaller than the ratio (= 12/5 = 2.4). The ratio of the number of flat tubes 63 constituting the first lower main heat exchange portion 61AL to the number of flat tubes 63 constituting the first lower sub heat exchange portion 62AL is not limited to 1.0. However, it is preferably within the range of 0.5 to 1.5. The ratio of the number of flat tubes 63 constituting the first upper main heat exchange portion 61AU to the number of flat tubes 63 constituting the first upper sub heat exchange portion 62AU is not limited to 2.4. It is preferable to be within the range of 1.7 to 3.0.

  In addition, here, the heat exchange units 60A to 60F are arranged side by side, and the heat exchange units 60B to 60F other than the first heat exchange unit 60A are sub-heated below the main heat exchange units 61B to 61F. Exchange parts 62B-62F are arranged.

  Next, the flow of the refrigerant in the outdoor heat exchanger 11 having the above configuration will be described.

  During the cooling operation, the outdoor heat exchanger 11 functions as a radiator for the refrigerant discharged from the compressor 8 (see FIG. 1).

  The refrigerant discharged from the compressor 8 (see FIG. 1) is sent to the gas side branch member 75 through the refrigerant pipe 19 (see FIG. 1). The refrigerant sent to the gas side diverting member 75 is diverted from the gas side refrigerant diverting mother pipe 76 to the gas side refrigerant diverting branch pipes 77AU, 77AL, 77B to 77F, and the respective gas side inlets and outlets of the first header collecting pipe 80. It is sent to the communication spaces 84AU, 84AL, 84B to 84F.

  The refrigerant sent to the gas side inlet / outlet communication spaces 84AU, 84AL, 84B to 84F is a flat tube 63 that constitutes the main heat exchange portions 61AU, 61AL, 61B to 61F of the corresponding heat exchange portions 60AU, 60AL, 60B to 60F. To be diverted to The refrigerant sent to each flat tube 63 is dissipated by heat exchange with outdoor air while flowing through the passage 63b, and merges in the folded communication spaces 92AU, 92AL, 92B to 92F of the second header collecting pipe 90. . That is, the refrigerant passes through the main heat exchange units 61AU, 61AL, 61B to 61F. At this time, the refrigerant dissipates heat from the superheated gas state until it becomes a liquid state close to a gas-liquid two-phase state or a saturated state.

  The refrigerant merged in each of the folded communication spaces 92AU, 92L, 92B to 92F is diverted to the flat tubes 63 that constitute the sub heat exchange portions 62AU, 62AL, 62B to 62F of the corresponding heat exchange portions 60AU, 60AL, 60B to 60F. The The refrigerant sent to each flat tube 63 dissipates heat by exchanging heat with outdoor air while flowing through the passage 63b, and merges in the liquid side inlet / outlet communication spaces 85A to 85F of the first header collecting pipe 80. That is, the refrigerant passes through the sub heat exchange units 62AU, 62AL, 62B to 62F. At this time, the refrigerant further dissipates heat until it becomes a supercooled liquid state from a liquid state close to a gas-liquid two-phase state or a saturated state.

  The refrigerant sent to each of the liquid side inlet / outlet communication spaces 85 </ b> A to 85 </ b> F is sent to the liquid side refrigerant diversion pipes 72 </ b> A to 72 </ b> F of the liquid side refrigerant diversion member 70 and merges in the liquid side refrigerant diverter 71. The refrigerant merged in the liquid side refrigerant divider 71 is sent to the outdoor expansion valve 12 (see FIG. 1) through the refrigerant pipe 20 (see FIG. 1).

  During the heating operation, the outdoor heat exchanger 11 functions as an evaporator for the refrigerant decompressed by the outdoor expansion valve 12 (see FIG. 1).

  The refrigerant decompressed in the outdoor expansion valve 12 is sent to the liquid side refrigerant distribution member 70 through the refrigerant pipe 20 (see FIG. 1). The refrigerant sent to the liquid side refrigerant diverting member 70 is diverted from the liquid side refrigerant diverter 71 to the liquid side refrigerant diverting pipes 72A to 72F, and the liquid side inlet / outlet communication spaces 85A to 85F of the first header collecting pipe 80 are separated. Sent to.

  The refrigerant sent to each of the liquid side inlet / outlet communication spaces 85A to 85F is diverted to the flat tubes 63 constituting the sub heat exchange portions 62AU, 62AL, 62B to 62F of the corresponding heat exchange portions 60AU, 60AL, 60B to 60F. . The refrigerant sent to each flat tube 63 evaporates by heat exchange with outdoor air while flowing through the passage 63b, and merges in each folded communication space 92AU, 92AL, 92B to 92F of the second header collecting tube 90. . That is, the refrigerant passes through the sub heat exchange units 62AU, 62AL, 62B to 62F. At this time, the refrigerant evaporates from a gas-liquid two-phase state with a lot of liquid components to a gas state close to a saturated state with a gas-liquid two-phase state with many gas components.

  The refrigerant merged in each of the folded communication spaces 92AU, 92AL, 92B to 92F is diverted to the flat pipe 63 constituting the main heat exchange portions 61AU, 61AL, 61B to 61F of the corresponding heat exchange portions 60AU, 60AL, 60B to 60F. The The refrigerant sent to each flat tube 63 is evaporated (heated) by heat exchange with outdoor air while flowing through the passage 63b, and the gas side inlet / outlet communication spaces 84AU, 84AL of the first header collecting pipe 80 are evaporated. , 84B to 84F. That is, the refrigerant passes through the main heat exchange units 61AU, 61AL, 61B to 61F. At this time, the refrigerant is further evaporated (heated) from a gas-liquid two-phase state with a lot of gas components or a gas state close to saturation to a superheated gas state.

  The refrigerant sent to the gas side inlet / outlet communication spaces 84AU, 84AL, 84B to 84F is sent to the gas side refrigerant branch branches 77AU, 77AL, 77B to 77F of the gas side refrigerant diverting member 75, and the gas side refrigerant diversion base. Merge at the pipe 76. The refrigerant merged in the gas-side refrigerant branch mother pipe 76 is sent to the suction side of the compressor 8 (see FIG. 1) through the refrigerant pipe 19 (see FIG. 1).

  During the defrosting operation, the outdoor heat exchanger 11 functions as a radiator for the refrigerant discharged from the compressor 8 (see FIG. 1), similarly to the cooling operation. In addition, since the flow of the refrigerant in the outdoor heat exchanger 11 during the defrosting operation is the same as that during the cooling operation, the description thereof is omitted here. However, unlike the cooling operation, during the defrosting operation, the refrigerant mainly dissipates heat while melting the frost attached to the heat exchange units 60AU, 60AL, 60B to 60F.

(4) Features The outdoor heat exchanger 11 (heat exchanger) of this embodiment has the following features.

<A>
As described above, the heat exchanger 11 of the present embodiment includes a plurality of flat tubes 63 that are arranged one above the other and that have a refrigerant passage 63b formed therein, and a plurality of air that flows between adjacent flat tubes 63. And a plurality of fins 64 that are partitioned into the ventilation path. The flat tube 63 is divided into a plurality of heat exchange units 60A to 60F, and each of the heat exchange units 60A to 60F includes a main heat exchange unit 61A to 61F connected to the gas side inlet / outlet communication spaces 84A to 84F, and a main Sub heat exchange units 62A to 62F connected in series to the main heat exchange units 61A to 61F and connected to the liquid side inlet / outlet communication spaces 85A to 85F at vertical positions different from the heat exchange units 61A to 61F. And here, the 1st main heat exchanging part 61A which constitutes the 1st heat exchanging part 60A containing the lowermost flat tube 63A among a plurality of heat exchanging parts 60A-60F seems to contain the lowermost flat pipe 63A. Is arranged.

  On the other hand, in the conventional heat exchanger, a plurality of flat tubes are divided into a plurality of heat exchanging portions arranged vertically, and each heat exchanging portion is below the main heat exchanging portion and the main heat exchanging portion. And a sub heat exchange part connected in series to the main heat exchange part. For this reason, in the conventional heat exchanger, the sub heat exchanging portion constituting the lowermost heat exchanging portion of the heat exchanging portions is arranged to include the lowermost flat tube (flat tube 63A in the present embodiment). ing. And when such a conventional heat exchanger is employed in an air conditioner that switches between heating operation and defrosting operation, it melts the frost adhering to the lowermost heat exchange part during the defrosting operation. The required time tends to be longer than the time required to melt the frost attached to the heat exchange part on the upper stage side than the lowermost heat exchange part. First, the cause will be described.

  In this conventional configuration, when switching from heating operation (used as a refrigerant evaporator) to defrosting operation (used as a refrigerant radiator), a liquid state is placed in the lowermost sub heat exchange section including the lowermost flat tube. The refrigerant is easy to accumulate. Then, when the defrosting operation is performed in such a state, the refrigerant in the gas state first flows into the lowermost main heat exchange part, and then flows into the lowermost sub heat exchange part. It takes time to evaporate the liquid refrigerant accumulated in the sub heat exchange section. That is, in the configuration of the conventional heat exchanger, the lowermost sub heat exchange section including the lowermost flat tube during the defrosting operation is located on the downstream side of the refrigerant flow. It is estimated that this is one of the causes that the time required to melt the frost attached to the replacement part becomes long.

  Further, in this conventional configuration, when the refrigerant in the gas state branches during defrosting operation and flows into the main heat exchange part of each heat exchange part, the heat exchange on the upper stage side is affected by the influence of the liquid head of the refrigerant. The flow rate of the refrigerant in the gas state flowing into the lowermost heat exchanging portion is smaller than that of the lower portion, and the time required for melting the frost attached to the lowermost heat exchanging portion is lengthened. Since the degree of the liquid head is affected by the height position of the flat tube included in the sub heat exchange unit constituting the heat exchange unit, the lowermost sub heat exchange unit includes the lowermost flat tube. And the liquid head of a refrigerant | coolant is large and the flow volume of the refrigerant | coolant of the gas state which flows in at the time of a defrost operation further decreases. That is, in the configuration of the conventional heat exchanger, the flow rate of the refrigerant in the gas state flowing into the lowermost heat exchanging part by the refrigerant liquid head during the defrosting operation is reduced. It is presumed that this is one of the causes that the time required to melt the frost attached to the surface becomes longer.

  Further, in this conventional configuration, since the lower end portion of the fin close to the lowermost flat tube is in contact with the drain pan (the bottom frame 42 in the present embodiment), the lowermost sub heat exchange section including the lowermost flat tube Heat is easily generated from to the drain pan. And, when the defrosting operation is performed in such a state, the heat in the lowermost heat exchanging portion is less likely to rise than the upper heat exchanging portion due to heat radiation from the lowermost sub heat exchanging portion to the drain pan. The time required to melt the frost adhering to the lowermost heat exchanging portion is lengthened. That is, in the conventional heat exchanger configuration, the heat radiation from the lowermost sub heat exchange part including the lowermost flat tube to the drain pan melts the frost adhering to the lowermost heat exchange part during the defrosting operation. It is presumed that this is one of the causes of the longer time required for

  As described above, in the conventional heat exchanger, when the lowermost sub heat exchanging portion includes the lowermost flat tube, the heating exchanger and the defrosting operation are switched to each other and the air conditioner is used. In addition, the time required to melt the frost attached to the lowermost heat exchange part is longer than the time required to melt the frost attached to the upper heat exchange part than the lowermost heat exchange part. Presumed to be longer.

  Therefore, here, unlike the conventional heat exchanger, as described above, the first main heat exchange part constituting the first heat exchange part 60A including the lowermost flat tube 63A among the heat exchange parts 60A to 60F. 61A is arranged so as to include the lowermost flat tube 63A.

  And when the heat exchanger 11 which has this structure is employ | adopted for the air conditioning apparatus 1 which switches between heating operation and defrost operation as mentioned above, when it pays attention to the 1st heat exchange part 60A, heating operation At the time of (used as a refrigerant evaporator), as shown in FIG. 8, the gas-liquid two-phase refrigerant flows into the first sub-heat exchanger 62A and flows into the first sub-heat exchanger 62A, as shown in FIG. The refrigerant in the state passes through the first sub heat exchange part 62A and the first main heat exchange part 61A including the lowermost flat tube 63A and is heated in this order, and flows out from the first heat exchange part 60A. Further, during the defrosting operation (used as a refrigerant radiator), as shown in FIG. 9, the gas state refrigerant flows into the first main heat exchange unit 61 </ b> A and into the first main heat exchange unit 61 </ b> A. The refrigerant passes through the first main heat exchange unit 61A including the lowermost flat tube 63A and the first sub heat exchange unit 62A in order, is cooled, and flows out from the first heat exchange unit 60A. That is, here, during the defrosting operation, the first main heat exchanging portion 61A including the lowermost flat tube 63A is positioned on the upstream side of the refrigerant flow. Therefore, here, the refrigerant in the gas state is allowed to flow into the first main heat exchange section 61A including the lowermost flat tube 63A, and the refrigerant in the liquid state collected in the first sub heat exchange section 62A in the lowermost stage is positively While heating and evaporating, it becomes possible to quickly increase the temperature in the first heat exchange section 60A in the lowermost stage, and thereby, during the defrosting operation as compared with the case where a conventional heat exchanger is employed. The time required to melt the frost attached to the lowermost heat exchange section 63A can be shortened.

  Thus, here, by adopting the heat exchanger 11 having the above-described configuration in the air conditioner 1 that performs switching between the heating operation and the defrosting operation, the lowermost heat exchanging unit 60A is used in the defrosting operation. The time required for melting the attached frost can be shortened.

<B>
In the heat exchanger 11 of the present embodiment, as described above, all of the heat exchange units 60B to 60F other than the first heat exchange unit 60A are arranged above the first heat exchange unit 60A. The first sub heat exchange unit 62A includes a first upper sub heat exchange unit 62AU and a first lower sub heat exchange unit 62AL below the first upper sub heat exchange unit 62AU. Moreover, the first main heat exchange unit 61A includes a first upper main heat exchange unit 61AU connected to the first upper sub heat exchange unit 62AU above the first upper sub heat exchange unit 62AU, and a first lower sub heat exchange. A first lower main heat exchange unit 61AL connected to the first lower sub heat exchange unit 62AL is provided below the exchange unit 62AL.

  In this configuration, when focusing on the first heat exchange unit 60A, during heating operation (used as a refrigerant evaporator), as shown in FIG. 8, the gas-liquid two-phase refrigerant is converted into the first upper sub heat exchange unit 62AU and It flows into the first lower sub heat exchanger 62AL. The refrigerant in the gas-liquid two-phase state that has flowed into the first upper sub heat exchange unit 62AU is the first upper main heat exchange located above the first upper sub heat exchange unit 62AU and the first upper sub heat exchange unit 62AU. It passes through the part 61AU in order, is heated, and flows out from 60 A of 1st heat exchange parts. The refrigerant in the gas-liquid two-phase state that has flowed into the first lower sub heat exchange unit 62AL is a first lower main located below the first lower sub heat exchange unit 62AL and the first lower sub heat exchange unit 62AL. The heat exchange unit 61AL is passed through in order and heated, and flows out from the first heat exchange unit 60A. Further, during the defrosting operation (used as a refrigerant radiator), as shown in FIG. 9, the gaseous refrigerant flows into the first upper main heat exchange unit 61AU and the first lower main heat exchange unit 61AL. And the refrigerant | coolant of the gas state which flowed into 1st upper side main heat exchange part 61AU is 1st upper side main heat exchange part 61AU and 1st upper side sub heat exchange part 62AU located under 1st upper side main heat exchange part 61AU. It passes through in order, is cooled, and flows out from 60 A of 1st heat exchange parts. The refrigerant in the gas state flowing into the first lower main heat exchange unit 61AL is the first lower main heat exchange unit 61AL and the first lower sub heat exchange unit located above the first lower main heat exchange unit 61AL. It passes through 62AL in order, is cooled, and flows out from the first heat exchange section 60A.

<C>
Further, as described above, the heat exchanger 11 of the present embodiment has the flat tubes 63 constituting the first lower main heat exchange portion 61AL corresponding to the number of flat tubes 63 constituting the first lower sub heat exchange portion 62AL. Is set to be smaller than the ratio of the number of flat tubes 63 constituting the first upper main heat exchanging portion 61AU to the number of flat tubes 63 constituting the first upper sub-heat exchanging portion 62AU. Yes.

  In the configuration <B>, the first upper sub heat exchange unit 62AU is disposed below the first upper main heat exchange unit 61AU, and the first lower main heat exchange unit 62AL is disposed below the first lower sub heat exchange unit 62AL. It becomes the structure which has 60 A of 1st heat exchange parts by which heat exchange part 61AL is arrange | positioned. In this configuration, during heating operation (used as a refrigerant evaporator), as shown in FIG. 8, the first lower sub heat exchange unit 62AL and the first lower main heat exchange unit 61AL in the first heat exchange unit 60A. The first lower main heat exchanging part (first lower heat exchanging part 60AL) is arranged below the first lower sub heat exchanging part 62AL after the refrigerant has passed through the first lower sub heat exchanging part 62AL. It will function as a so-called downflow type evaporator passing through 61AL. Here, in a downflow type evaporator, when a fluid in a gas-liquid two-phase state is sent downward and accompanied by a fluid diversion, fluid drift tends to occur. Therefore, also in the first lower sub heat exchange unit 62AL and the first lower main heat exchange unit 61AL, the first lower main heat exchange unit 61AL from the flat tube 63 constituting the first lower sub heat exchange unit 62AL. Since the refrigerant is diverted when the refrigerant is sent downward to the flat tube 63 constituting the refrigerant, there is a possibility that the refrigerant drifts. At this time, if the ratio of the number of flat tubes 63 constituting the first lower main heat exchange portion 61AL to the number of flat tubes 63 constituting the first lower sub heat exchange portion 62AL increases, refrigerant drift occurs. The fear increases.

  Therefore, here, as described above, for the first heat exchange section 60A, the flatness constituting the first lower main heat exchange section 61AL with respect to the number of flat tubes 63 constituting the first lower sub heat exchange section 62AL. The ratio of the number of tubes 63 is set so as to be smaller than the ratio of the number of flat tubes 63 constituting the first upper main heat exchange section 61AU to the number of flat tubes 63 constituting the first upper sub heat exchange section 62AU. doing.

  Accordingly, here, during the heating operation (used as a refrigerant evaporator), from the flat tube 63 constituting the first lower sub heat exchange portion 62AL to the flat tube 63 constituting the first lower main heat exchange portion 61AU. When sending the refrigerant downward, it is possible to suppress the drift of the refrigerant accompanying the flow of the refrigerant.

<D>
Moreover, as for the heat exchanger 11 of this embodiment, the heat exchange parts 60A-60F are arrange | positioned along with the upper and lower sides as mentioned above, and heat exchange parts 60B-60F other than 60 A of 1st heat exchange parts, Sub heat exchange parts 62B-62F are arranged below main heat exchange parts 61B-61F.

  In this configuration, focusing on the heat exchange units 60B to 60F other than the first heat exchange unit 60A, the refrigerant in the gas-liquid two-phase state is transferred to the sub heat exchange units 62B to 62F during heating operation (used as a refrigerant evaporator). The refrigerant in the gas-liquid two-phase state that flows in and flows into the sub heat exchange units 62B to 62F passes through the sub heat exchange units 62B to 62F and the main heat exchange units 61B to 61F located above the sub heat exchange units 62B to 62F. It passes and heats in order, and flows out from the heat exchange parts 60B-60F. Further, during the defrosting operation (used as a refrigerant radiator), the gaseous refrigerant flows into the main heat exchange units 61B to 61F, and the gaseous refrigerant that has flowed into the main heat exchange units 61B to 61F undergoes main heat exchange. The parts 61B to 61F and the sub heat exchanging parts 62B to 62F located below the main heat exchanging parts 61B to 61F are passed through and cooled in this order, and flow out of the heat exchanging parts 60B to 60F.

(5) Modification <A>
In the outdoor heat exchanger 11 (heat exchanger) of the above-described embodiment, the lowermost first heat exchange unit 60A including the lowermost flat tube 63A is included in the main heat exchange unit 61A so that the lowermost flat tube 63A is included. The first heat exchanging unit 60A, the first upper heat exchanging unit 60AU, and the first lower main heat exchanging unit 61AL are arranged to include the lowermost flat tube 63A. This is realized by dividing into an exchange unit 60AL (see FIGS. 6 to 9). In this configuration, two partition plates 86 are provided in the first header collecting pipe 80 so as to partition the first inlet / outlet communication space 82A corresponding to the first heat exchange part 60A into three inlet / outlet communication spaces 84AU, 85A, 84AL, and The partition plate 93 is provided in the second header collecting pipe 90 so as to partition the first folded communication space 92A corresponding to the first heat exchange section 60A into two folded communication spaces 92AU and 92AL. In this configuration, the first liquid side inlet / outlet communication space 85A is a liquid side inlet / outlet communication space common to the first upper heat exchange part 60AU and the first lower heat exchange part 60AL, and in this sense, the first upper heat The exchange unit 60AU and the first lower heat exchange unit 60AL are not independent heat exchange units.

  However, the configuration in which the lowermost first heat exchanging portion 60A including the lowermost flat tube 63A is arranged so that the main heat exchanging portion 61A includes the lowermost flat tube 63A is not limited thereto.

  For example, in the heat exchanger 11 of the above embodiment, the first header collecting pipe 80 is further provided with a partition plate that divides the first liquid side inlet / outlet communication space 85A into two upper and lower parts, thereby providing two liquid side inlet / outlet communication spaces, The first upper heat exchange unit 60AU and the first lower heat exchange unit 60AL may be independent heat exchange units.

  Specifically, in the outdoor heat exchanger 11 of this modification, as shown in FIGS. 10 to 14, a plurality of (here, seven) heat exchange units 60 </ b> A to 60 </ b> G in which a plurality of flat tubes 63 are arranged vertically. It is divided into. Specifically, here, in order from the bottom to the top, the first heat exchange unit 60A, the second heat exchange unit 60B, which is the lowest heat exchange unit, the sixth heat exchange unit 60F, and the seventh heat An exchange unit 60G is formed. The first heat exchange section 60A has four flat tubes 63 including a flat tube 63A at the lowest stage. The second heat exchanging unit 60B has 17 flat tubes 63. The third heat exchanging unit 60 </ b> C has 18 flat tubes 63. The fourth heat exchanging unit 60 </ b> D has 15 flat tubes 63. The fifth heat exchanging unit 60 </ b> E has 13 flat tubes 63. The sixth heat exchange part 60F has eleven flat tubes 63. The seventh heat exchanging part 60G has nine flat tubes 63.

  The first header collecting pipe 80 is partitioned into upper and lower portions by a partition plate 81, thereby forming entrance / exit communication spaces 82 </ b> A to 82 </ b> G corresponding to the heat exchange units 60 </ b> A to 60 </ b> G. In addition, each of the entrance / exit communication spaces 82 </ b> A to 82 </ b> G is divided into two vertically by a partition plate 83. Thereby, the upper side gas side inlet / outlet communication spaces 84B to 84G and the lower side liquid side inlet / outlet communication space are provided in the inlet / outlet communication spaces 82B to 82G excluding the first inlet / outlet communication space 82A corresponding to the first heat exchange section 60A. 85B to 85G are formed, and an upper first liquid side inlet / outlet communication space 85A and a lower first gas side inlet / outlet communication are provided in the first inlet / outlet communication space 82A corresponding to the first heat exchange section 60A. A space 84A is formed.

  The second gas side inlet / outlet communication space 84B communicates with the top twelve of the flat tubes 63 that constitute the second heat exchange section 60B, and the second liquid side inlet / outlet communication space 85B includes the second heat exchange section 60B. Are communicated with the remaining five flat tubes 63. The third gas side inlet / outlet communication space 84C communicates with twelve from the top of the flat tubes 63 constituting the third heat exchange part 60C, and the third liquid side inlet / outlet communication space 85C constitutes the third heat exchange part 60C. The remaining six flat tubes 63 communicate with the remaining flat tubes 63. The fourth gas side inlet / outlet communication space 84D communicates with the top ten of the flat tubes 63 that constitute the fourth heat exchange part 60D, and the fourth liquid side inlet / outlet communication space 85D constitutes the fourth heat exchange part 60D. The remaining five flat tubes 63 communicate with the remaining flat tubes 63. The fifth gas side inlet / outlet communication space 84E communicates with nine of the flat tubes 63 constituting the fifth heat exchanging part 60E from the top, and the fifth liquid side inlet / outlet communication space 85E constitutes the fifth heat exchange part 60E. The remaining four flat tubes 63 communicate with the remaining flat tubes 63. The sixth gas side inlet / outlet communication space 84F communicates with seven of the flat tubes 63 constituting the sixth heat exchange part 60F from the top, and the sixth liquid side inlet / outlet communication space 85F constitutes the sixth heat exchange part 60F. The remaining four flat tubes 63 communicate with the remaining flat tubes 63. The seventh gas side inlet / outlet communication space 84G communicates with the top six of the flat tubes 63 constituting the seventh heat exchange part 60G, and the seventh liquid side inlet / outlet communication space 85G constitutes the seventh heat exchange part 60G. The remaining three flat tubes 63 communicate with the remaining flat tubes 63. The first gas side inlet / outlet communication space 84A communicates from the bottom including the lowermost flat tube 63A among the flat tubes 63 constituting the first heat exchange section 60A, and the first liquid side inlet / outlet communication space 85A It communicates with the remaining two of the flat tubes 63 constituting the first heat exchange part 60A.

  Here, the flat tubes 63 communicating with the gas side inlet / outlet communication spaces 84A to 84G are referred to as main heat exchange portions 61A to 61G, and the flat tubes 63 communicating with the liquid side inlet / outlet communication spaces 85A to 85G are sub heat exchange portions 62A to 62G. And That is, in the second inlet / outlet communication space 82B, the second gas side inlet / outlet communication space 84B communicates with twelve from the top of the flat tubes 63 constituting the second heat exchange section 60B (second main heat exchange section 61B), The second liquid side inlet / outlet communication space 85B communicates with the remaining five flat tubes 63 of the flat tubes 63 constituting the second heat exchange section 60B (second sub heat exchange section 62B). In the third inlet / outlet communication space 82C, the third gas side inlet / outlet communication space 84C communicates with the top twelve of the flat tubes 63 constituting the third heat exchange section 60C (third main heat exchange section 61C), the third The liquid side inlet / outlet communication space 85C communicates with the remaining six flat tubes 63 of the flat tube 63 constituting the third heat exchange unit 60C (third sub heat exchange unit 62C). In the fourth inlet / outlet communication space 82D, the fourth gas-side inlet / outlet communication space 84D communicates with the top ten of the flat tubes 63 constituting the fourth heat exchange section 60D (fourth main heat exchange section 61D), the fourth. The liquid side inlet / outlet communication space 85D communicates with the remaining five flat tubes 63 of the flat tubes 63 constituting the fourth heat exchange portion 60D (fourth sub heat exchange portion 62D). In the fifth inlet / outlet communication space 82E, the fifth gas side inlet / outlet communication space 84E communicates with the top nine of the flat tubes 63 constituting the fifth heat exchange section 60E (fifth main heat exchange section 61E), fifth The liquid side inlet / outlet communication space 85E communicates with the remaining four flat tubes 63 of the flat tube 63 constituting the fifth heat exchange unit 60E (fifth sub heat exchange unit 62E). In the sixth inlet / outlet communication space 82F, the sixth gas side inlet / outlet communication space 84F communicates with the top seven of the flat tubes 63 constituting the sixth heat exchange section 60F (sixth main heat exchange section 61F), The liquid side inlet / outlet communication space 85F communicates with the remaining four flat tubes 63 of the flat tube 63 constituting the fifth heat exchanging portion 60F (sixth sub heat exchanging portion 62F). In the seventh inlet / outlet communication space 82G, the seventh gas side inlet / outlet communication space 84G communicates with the top six of the flat tubes 63 constituting the seventh heat exchange unit 60G (seventh main heat exchange unit 61G), The liquid side inlet / outlet communication space 85G communicates with the remaining three flat tubes 63 of the flat tube 63 constituting the seventh heat exchange unit 60G (seventh sub heat exchange unit 62G). In the first inlet / outlet communication space 82A, the first gas side inlet / outlet communication space 84A communicates from the bottom including the lowest flat tube 63A among the flat tubes 63 constituting the first heat exchange section 60A (first main The heat exchange part 61A) and the first liquid side inlet / outlet communication space 85A communicate with the remaining two flat tubes 63 constituting the first heat exchange part 60A (first sub heat exchange part 62A).

  Further, the first header collecting pipe 80 includes a liquid side diverting member 70 for diverting the refrigerant sent from the outdoor expansion valve 12 (see FIG. 1) during the heating operation to the liquid side inlet / outlet communication spaces 85A to 85G, and for cooling. A gas side diverting member 75 that diverts and sends the refrigerant sent from the compressor 8 (see FIG. 1) during operation to the gas side inlet / outlet communication spaces 84A to 84G is connected.

  The liquid side flow dividing member 70 extends from the liquid side refrigerant flow divider 71 connected to the refrigerant pipe 20 (see FIG. 1) and the liquid side refrigerant flow divider 71 and is connected to the liquid side inlet / outlet communication spaces 85A to 85G. Liquid side refrigerant distribution pipes 72A to 72G. Here, the liquid side refrigerant distribution pipes 72A to 72G have capillary tubes, and those having a length and an inner diameter corresponding to the distribution ratio to the sub heat exchange units 62A to 62G are used.

  The gas side branch member 75 extends from the gas side refrigerant branch mother pipe 76 connected to the refrigerant pipe 19 (see FIG. 1) and the gas side refrigerant branch mother pipe 76, and is connected to the gas side inlet / outlet communication spaces 84A to 84G. Gas side refrigerant branch branch pipes 77A to 77G.

  As for the 2nd header collection pipe 90, the internal space is divided up and down with the partition plate 91, and the folding | returning communication space 92A-92G corresponding to each heat exchange part 60A-60G is formed. As described above, the internal space of the second header collecting pipe 90 is not limited to the configuration just partitioned by the partition plate 91, and the flow state of the refrigerant in the second header collecting pipe 90 is good. It is also possible to adopt a configuration that is devised for maintaining the above.

  And each return | turnback communication space 92A-92G is connected to all the flat tubes 63 which comprise the corresponding heat exchange parts 60A-60G. That is, the second folded communication space 92B communicates with all of the 17 flat tubes 63 constituting the second heat exchange unit 60B. The third folded communication space 92C communicates with all of the 18 flat tubes 63 constituting the third heat exchange unit 60C. The fourth folded communication space 92D communicates with all of the 15 flat tubes 63 that constitute the fourth heat exchange unit 60D. The fifth folded communication space 92E communicates with all of the 13 flat tubes 63 constituting the fifth heat exchange unit 60E. The sixth folded communication space 92F communicates with all of the eleven flat tubes 63 constituting the sixth heat exchange unit 60F. The seventh folded communication space 92G communicates with all nine flat tubes 63 constituting the seventh heat exchange unit 60G. The first folded communication space 92A communicates with all of the four flat tubes 63 including the lowermost flat tube 63A constituting the first heat exchange section 60A.

  Thereby, each heat exchange part 60A-60G is the sub heat exchange part connected in series to main heat exchange part 61A-61G in the upper and lower positions different from main heat exchange part 61A-61G, and main heat exchange part 61A-61G. 62A-62G. That is, the second heat exchange unit 60B is positioned directly below the 12 flat tubes 63 constituting the second main heat exchange unit 61B communicating with the second gas side inlet / outlet communication space 84B and the second main heat exchange unit 61B. The five flat tubes 63 constituting the second sub heat exchange portion 62B communicating with the second liquid side inlet / outlet communication space 85B are connected in series through the second folded communication space 92B. Yes. The third heat exchange unit 60C is positioned directly below the twelve flat tubes 63 constituting the third main heat exchange unit 61C communicating with the third gas side inlet / outlet communication space 84C, and the third main heat exchange unit 61C. The six flat tubes 63 constituting the third sub heat exchange portion 62C communicating with the third liquid side inlet / outlet communication space 85C are connected in series through the third folded communication space 92C. The fourth heat exchange part 60D is located immediately below the ten flat tubes 63 constituting the fourth main heat exchange part 61D communicating with the fourth gas side inlet / outlet communication space 84D and the fourth main heat exchange part 61D. The five flat tubes 63 constituting the fourth sub heat exchange section 62D communicating with the fourth liquid side inlet / outlet communication space 85D are connected in series through the fourth folded communication space 92D. The fifth heat exchanging part 60E is located immediately below the nine flat tubes 63 constituting the fifth main heat exchanging part 61E communicating with the fifth gas side inlet / outlet communication space 84E and the fifth main heat exchanging part 61E. The four flat tubes 63 constituting the fifth sub heat exchange section 62E communicating with the fifth liquid side inlet / outlet communication space 85E are connected in series through the fifth return communication space 92E. The sixth heat exchange part 60F is located directly below the seven flat tubes 63 constituting the sixth main heat exchange part 61F communicating with the sixth gas side inlet / outlet communication space 84F and the sixth main heat exchange part 61F. The four flat tubes 63 constituting the sixth sub heat exchange part 62F communicating with the sixth liquid side inlet / outlet communication space 85F are connected in series through the sixth folded communication space 92F. The seventh heat exchanging part 60G is located immediately below the six flat tubes 63 constituting the seventh main heat exchanging part 61G communicating with the seventh gas side inlet / outlet communication space 84G and the seventh main heat exchanging part 61G. The three flat tubes 63 constituting the seventh sub heat exchange portion 62G communicating with the seventh liquid side inlet / outlet communication space 85G are connected in series through the seventh folded communication space 92G. The first heat exchange section 60A includes two flat pipes 63 including a lowermost flat pipe 63A constituting the first main heat exchange section 61A communicating with the first gas side inlet / outlet communication space 84A, and the first main heat exchange. Two flat tubes 63 that constitute the first sub heat exchange portion 62A that is located immediately above the portion 61A and communicates with the first liquid side inlet / outlet communication space 85A are connected in series through the first folded communication space 92A. It has a configuration.

  As described above, as in the above-described embodiment, a plurality of flat tubes 63 that are arranged one above the other and that have a refrigerant passage 63b formed therein, and a plurality of air that flows between adjacent flat tubes 63 are provided. And a plurality of fins 64 partitioned into the ventilation path. The flat tube 63 is divided into a plurality of heat exchange units 60A to 60G, and each of the heat exchange units 60A to 60G is a main heat exchange unit 61A to 61G and a main position at a different vertical position from the main heat exchange units 61A to 61G. Sub heat exchange units 62A to 62G connected in series to the heat exchange units 61A to 61G. And the 1st main heat exchange part 61A which comprises the 1st heat exchange part 60A containing the lowermost flat tube 63A among several heat exchange parts 60A-60G is arrange | positioned so that the lowermost flat pipe 63A may be included. ing.

  For this reason, in the structure of this modification, the time required for melting the frost adhering to the heat exchange part 60A of the lowest stage at the time of a defrost operation can be shortened similarly to the said embodiment.

  In addition, here, all of the heat exchange units 60B to 60G other than the first heat exchange unit 60A are arranged above the first heat exchange unit 60A. In the first heat exchange unit 60A, the first main heat exchange unit 61A is disposed below the first sub heat exchange unit 62A.

  In the configuration of the present modification, focusing on the first heat exchange unit 60A, during heating operation (used as a refrigerant evaporator), as shown in FIG. 13, the gas-liquid two-phase refrigerant is converted into the first sub heat exchange unit. The refrigerant in the gas-liquid two-phase state that flows into 62A and flows into the first sub heat exchange unit 62A is a first main heat exchange unit positioned below the first sub heat exchange unit 62A and the first sub heat exchange unit 62A. It passes through 61A in order, is heated, and flows out from 60A of 1st heat exchange parts. Further, during the defrosting operation (used as a radiator radiator), as shown in FIG. 14, the gaseous refrigerant flows into the first main heat exchanging part 61A and into the first main heat exchanging part 61A. The refrigerant passes through the first main heat exchanging part 61A and the first sub heat exchanging part 62A located above the first main heat exchanging part 61A in order, is cooled, and flows out of the first heat exchanging part 60A. Become.

  In the above configuration, since the first main heat exchanging part 61A is disposed below the first sub heat exchanging part 62A, the heating operation (refrigerant) is performed as in the above embodiment. As shown in FIG. 13, the first heat exchanging part 60A is disposed below the first sub heat exchanging part 62A after the refrigerant has passed through the first sub heat exchanging part 62A. It functions as a so-called downflow type evaporator that passes through the 1 main heat exchange section 61A. For this reason, also in the first heat exchanging part 60A of the present modification, the refrigerant is directed downward from the flat pipe 63 constituting the first sub heat exchanging part 62A to the flat pipe 63 constituting the first main heat exchanging part 61A. Since the refrigerant is diverted when it is sent, there is a risk of refrigerant drift. At this time, if the ratio of the number of the flat tubes 63 constituting the first main heat exchange portion 61A to the number of the flat tubes 63 constituting the first sub heat exchange portion 62A is increased, the risk of refrigerant drift increases. .

  Therefore, here, the ratio of the number (two) of the flat tubes 63 constituting the first main heat exchange portion 61A to the number (two) of the flat tubes 63 constituting the first sub heat exchange portion 62A (= 2 / 2 = 1.0), the flat tubes constituting the main heat exchange portions 61A to 61G with respect to the number of flat tubes (3 to 6) constituting the sub heat exchange portions 62B to 62G in the other heat exchange portions 60B to 60G It is set to be smaller than the ratio of 63 numbers (6 to 12) (= 7/4 to 12/5 = 1.8 to 2.4). The ratio of the number of flat tubes 63 constituting the first main heat exchange portion 61A to the number of flat tubes 63 constituting the first sub heat exchange portion 62A is not limited to 1.0, but is 0. It is preferable to be within the range of .5 to 1.5. Further, the ratio of the number of flat tubes 63 constituting the other main heat exchange portions 61B to 61G to the number of flat tubes 63 constituting the other sub heat exchange portions 62B to 62G is limited to 1.8 to 2.4. Although it is not performed, it is preferable to set it within the range of 1.7 to 3.0.

  Thereby, here, similarly to the above-described embodiment, during the heating operation (used as a refrigerant evaporator), the flat tube 63 constituting the first main heat exchange unit 61A from the flat tube 63 constituting the first sub heat exchange unit 62A is used. When the refrigerant is sent downward to the pipe 63, it is possible to suppress the drift of the refrigerant accompanying the flow of the refrigerant.

<B>
In the said embodiment and modification <A>, although this invention was applied with respect to the outdoor heat exchanger 11 which has six or seven heat exchange parts, it is not limited to this, The number of heat exchange parts is There may be fewer than six or more than seven.

  In addition, the number of flat tubes 63 constituting each heat exchange unit 60A to 60G and how to divide the number of main heat exchange units 61A to 61G and sub heat exchange units 62A to 62G in each heat exchange unit 60A to 60G The present invention is not limited to the embodiment and the modified example <A>.

  In the above embodiment and the modified example <A>, the present invention is applied to the outdoor heat exchanger 11 provided in the top-blowing outdoor unit 2, but the outdoor unit provided in another type of outdoor unit is used. The present invention may be applied to a heat exchanger.

  The present invention includes a plurality of flat tubes arranged vertically and having a refrigerant passage formed therein, and a plurality of fins that are divided into a plurality of ventilation paths through which air flows between adjacent flat tubes. Widely applicable to exchangers.

11 Outdoor heat exchanger (heat exchanger)
60A-60G heat exchange part 60A first heat exchange part 61A-61G main heat exchange part 61A first main heat exchange part 61AU first upper main heat exchange part 61AL first lower main heat exchange part 62A-62G sub heat exchange part 62A 1st sub heat exchange part 62AU 1st upper sub heat exchange part 62AL 1st lower sub heat exchange part 63 Flat tube 63b Passage 64 Fin

JP 2012-163313 A

Claims (6)

A plurality of flat tubes (63) arranged vertically and having a refrigerant passage (63b) formed therein;
A plurality of fins (64) partitioning into a plurality of ventilation paths through which air flows between the adjacent flat tubes;
Have
The flat tube is divided into a plurality of heat exchange parts (60A to 60G),
Each of the heat exchange units includes a main heat exchange unit (61A to 61G), a sub heat exchange unit (62A to 62G) connected in series to the main heat exchange unit at a different vertical position from the main heat exchange unit, Have
The heat exchange part including the lowermost flat tube among the heat exchange parts is defined as a first heat exchange part (60A), and the main heat exchange part and the sub heat exchange part constituting the first heat exchange part are the first mains. When the heat exchange part (61A) and the first sub heat exchange part (62A) are used,
The first main heat exchange part is disposed so as to include the flattened tube at the lowermost stage,
Heat exchanger (11). All the heat exchange parts other than the first heat exchange part are arranged above the first heat exchange part,
The first main heat exchange unit has the first main heat exchange unit disposed below the first sub heat exchange unit.
The heat exchanger according to claim 1. The ratio of the number of the flat tubes constituting the first main heat exchange portion to the number of the flat tubes constituting the first sub heat exchange portion constitutes the sub heat exchange portion in the other heat exchange portion. It is set to be smaller than the ratio of the number of the flat tubes constituting the main heat exchange part to the number of the flat tubes,
The heat exchanger according to claim 2. All the heat exchange parts other than the first heat exchange part are arranged above the first heat exchange part,
The first sub heat exchange part includes a first upper sub heat exchange part (62AU) and a first lower sub heat exchange part (62AL) below the first upper sub heat exchange part. ,
The first main heat exchange section includes a first upper main heat exchange section (61AU) connected to the first upper sub heat exchange section above the first upper sub heat exchange section, and the first lower sub heat exchange section. A first lower main heat exchange part (61AL) connected to the first lower sub heat exchange part below the heat exchange part,
The heat exchanger according to claim 1. The ratio of the number of the flat tubes constituting the first lower main heat exchange portion to the number of the flat tubes constituting the first lower sub heat exchange portion constitutes the first upper sub heat exchange portion. It is set to be smaller than the ratio of the number of the flat tubes constituting the first upper main heat exchange section with respect to the number of the flat tubes,
The heat exchanger according to claim 4. The heat exchange part is arranged side by side up and down,
The heat exchange unit other than the first heat exchange unit has the sub heat exchange unit disposed below the main heat exchange unit,
The heat exchanger according to any one of claims 1 to 5.

Images