CN110603421A - Heat exchanger - Google Patents

Heat exchanger Download PDF

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Publication number
CN110603421A
CN110603421A CN201880030000.2A CN201880030000A CN110603421A CN 110603421 A CN110603421 A CN 110603421A CN 201880030000 A CN201880030000 A CN 201880030000A CN 110603421 A CN110603421 A CN 110603421A
Authority
CN
China
Prior art keywords
heat exchange
exchange portion
flat tubes
refrigerant
sub
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN201880030000.2A
Other languages
Chinese (zh)
Inventor
佐藤健
山田甲树
神藤正宪
织谷好男
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Daikin Industries Ltd
Original Assignee
Daikin Industries Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Daikin Industries Ltd filed Critical Daikin Industries Ltd
Publication of CN110603421A publication Critical patent/CN110603421A/en
Pending legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D1/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators
    • F28D1/02—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid
    • F28D1/04—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits
    • F28D1/047—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits the conduits being bent, e.g. in a serpentine or zig-zag
    • F28D1/0475—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits the conduits being bent, e.g. in a serpentine or zig-zag the conduits having a single U-bend
    • F28D1/0476—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits the conduits being bent, e.g. in a serpentine or zig-zag the conduits having a single U-bend the conduits having a non-circular cross-section
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D1/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators
    • F28D1/02—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid
    • F28D1/0233—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with air flow channels
    • F28D1/024—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with air flow channels with an air driving element
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D1/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators
    • F28D1/02—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid
    • F28D1/04—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits
    • F28D1/053—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits the conduits being straight
    • F28D1/0535—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits the conduits being straight the conduits having a non-circular cross-section
    • F28D1/05366—Assemblies of conduits connected to common headers, e.g. core type radiators
    • F28D1/05383—Assemblies of conduits connected to common headers, e.g. core type radiators with multiple rows of conduits or with multi-channel conduits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
    • F28F9/02—Header boxes; End plates
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
    • F28F9/02—Header boxes; End plates
    • F28F9/0202—Header boxes having their inner space divided by partitions
    • F28F9/0204—Header boxes having their inner space divided by partitions for elongated header box, e.g. with transversal and longitudinal partitions
    • F28F9/0209—Header boxes having their inner space divided by partitions for elongated header box, e.g. with transversal and longitudinal partitions having only transversal partitions
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
    • F28F9/02—Header boxes; End plates
    • F28F9/026—Header boxes; End plates with static flow control means, e.g. with means for uniformly distributing heat exchange media into conduits
    • F28F9/027—Header boxes; End plates with static flow control means, e.g. with means for uniformly distributing heat exchange media into conduits in the form of distribution pipes
    • F28F9/0275—Header boxes; End plates with static flow control means, e.g. with means for uniformly distributing heat exchange media into conduits in the form of distribution pipes with multiple branch pipes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B39/00—Evaporators; Condensers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
    • F28D2021/0019—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for
    • F28D2021/0068—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for refrigerant cycles
    • F28D2021/0071—Evaporators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F1/00—Tubular elements; Assemblies of tubular elements
    • F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
    • F28F1/12—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element
    • F28F1/24—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely
    • F28F1/32—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely the means having portions engaging further tubular elements

Abstract

The flat tubes (63) that constitute the heat exchanger (11) are divided into a plurality of heat exchange sections (60A-60G). Each of the heat exchange sections (60A-60G) has a main heat exchange section (61A-61G); and sub heat exchange sections (62A-62G) connected in series with the main heat exchange sections (61A-61G) at different upper and lower positions. The 1 st heat exchange part (60A) comprising the lowermost flat tube (63A), and the 1 st main heat exchange part (61A) thereof are arranged to comprise the lowermost flat tube (63A).

Description

Heat exchanger
Technical Field
The present invention relates to a heat exchanger, and more particularly, to a heat exchanger having a plurality of flat tubes arranged in a vertical direction and having a refrigerant passage formed therein, and a plurality of fins dividing a space between the adjacent flat tubes into a plurality of air passages through which air flows.
Background
A heat exchanger conventionally housed in an outdoor unit (heat exchange unit) of an air conditioning apparatus generally employs a heat exchanger having a plurality of flat tubes arranged one above another and a plurality of fins that divide between adjacent flat tubes a plurality of air passages through which air flows. As shown in patent document 1 (japanese unexamined patent publication No. 2012-163313), the heat exchanger includes a plurality of flat tubes divided into a plurality of heat exchange portions arranged vertically, each of the heat exchange portions including a main heat exchange portion and a sub heat exchange portion located below the main heat exchange portion and connected in series with the main heat exchange portion.
Documents of the prior art
Patent document
Patent document 1:
japanese unexamined patent publication No. 2012-163313
Disclosure of Invention
Problems to be solved by the invention
The above-described conventional heat exchanger is used in an apparatus for air conditioning by switching between a heating operation and a defrosting operation. In this case, the conventional heat exchanger is used as an evaporator of the refrigerant during the air-warming operation of the air-conditioning apparatus, and the conventional heat exchanger is used as a radiator of the refrigerant during the defrosting operation of the air-conditioning apparatus. Specifically, when the conventional heat exchanger is used as an evaporator of refrigerant, refrigerant in a gas-liquid two-phase state is branched and flows into the sub heat exchange portions constituting the respective heat exchange portions, and the refrigerant in the gas-liquid two-phase state flowing into the sub heat exchange portions passes through the sub heat exchange portion and the main heat exchange portion in this order, is heated, and flows out through the respective heat exchange portions and is collected. In addition, when the conventional heat exchanger is used as a radiator of refrigerant, gaseous refrigerant is branched and flows into the main heat exchange portion of each heat exchanger, and the gaseous refrigerant flowing into the main heat exchange portion is cooled by passing through the main heat exchange portion and the sub heat exchange portion in order, and then flows out of each heat exchange portion and is collected.
However, in the air-conditioning apparatus using the conventional heat exchanger, it takes time to melt frost attached to the heat exchange portion constituting the lowermost stage and it takes time to melt frost attached to the heat exchange portion of the lowermost stage rather than to melt frost attached to the heat exchange portion of the uppermost stage in the defrosting operation. Therefore, frost may remain in the lowermost heat exchange portion after the defrosting operation, resulting in incomplete defrosting, and the defrosting operation time needs to be extended to prevent frost from remaining in the lowermost heat exchange portion.
Means for solving the problems
The invention provides a heat exchanger having a plurality of flat tubes arranged vertically and forming a refrigerant passage therein, and a plurality of fins dividing a space between adjacent flat tubes into a plurality of air passages through which air flows, wherein the time for melting frost adhering to a lowermost heat exchange portion in a defrosting operation is shortened in an air conditioning apparatus for switching between a heating operation and the defrosting operation.
Effects of the invention
The heat exchanger according to claim 1 includes a plurality of flat tubes arranged in a vertical direction and having a refrigerant passage formed therein, and a plurality of fins for partitioning a space between the adjacent flat tubes into a plurality of air passages through which air flows. The flat tube is divided into a plurality of heat exchange portions, each heat exchange portion having a main heat exchange portion connected to the gas side inlet and outlet communication space; and an auxiliary heat exchange part which is located at a different upper and lower position from the main heat exchange part, and is connected in series with the main heat exchange part and is connected with the liquid side inlet and outlet communication space. Among them, in the heat exchange portion, if the heat exchange portion including the flat tube of the lowermost stage is regarded as the 1 st heat exchange portion, and the main heat exchange portion and the sub heat exchange portion constituting the 1 st heat exchange portion are regarded as the 1 st main heat exchange portion and the 1 st sub heat exchange portion, the 1 st main heat exchange portion is arranged to include the flat tube of the lowermost stage.
First, the reason why it takes time to melt frost adhering to the lowermost heat exchange portion in the defrosting operation of the conventional heat exchanger in the air conditioning apparatus for switching between the air-warming operation and the defrosting operation rather than melting frost adhering to the upper stage of the lowermost heat exchange portion will be described.
In the above-described conventional heat exchanger, the plurality of flat tubes are divided into a plurality of heat exchange portions arranged vertically, each of the heat exchange portions having a main heat exchange portion and an auxiliary heat exchange portion located below the main heat exchange portion and connected in series with the main heat exchange portion. Therefore, in the conventional heat exchanger, the sub heat exchange portion constituting the lowermost heat exchange portion among the heat exchange portions is arranged to include the lowermost flat tubes.
In such a conventional configuration, when switching from the heating operation (used as a refrigerant evaporator) to the defrosting operation (used as a refrigerant radiator), the liquid refrigerant tends to be retained in the lowermost sub heat exchange portion including the lowermost flat tubes. In the defrosting operation in this state, the gaseous refrigerant flows into the lowermost sub heat exchange unit after first flowing into the main heat exchange unit, and then flows into the lowermost sub heat exchange unit. That is, in the conventional heat exchanger structure, the lowermost sub heat exchange portion including the lowermost flat tubes is located on the downstream side where the refrigerant flows during the defrosting operation, and therefore, it is estimated that this is one of the reasons why the time required to melt the frost adhering to the lowermost heat exchange portion during the defrosting operation is long.
In this configuration, when the gaseous refrigerant is branched and flows into the main heat exchange portion of each heat exchange portion during the defrosting operation, the flow rate of the gaseous refrigerant flowing into the heat exchange portion of the lowest stage is smaller than that of the heat exchange portion of the upper stage due to the influence of the refrigerant liquid head, and therefore, the time required for melting the frost adhering to the heat exchange portion of the lowest stage is longer. Further, since the level of the liquid head is affected by the height position of the flat tubes in the sub heat exchange portions constituting the heat exchange portion, if the sub heat exchange portion at the lowermost stage includes the flat tubes at the lowermost stage, the refrigerant liquid head is large, and the amount of the gaseous refrigerant flowing in during the defrosting operation is small. That is, in the above-described conventional heat exchanger structure, since the flow rate of the gaseous refrigerant flowing into the lowermost heat exchange portion is decreased by the liquid head of the refrigerant during the defrosting operation, it is estimated that this is one of the reasons why the time required to melt the frost adhering to the lowermost heat exchange portion is long during the defrosting operation.
In addition, in such a conventional structure, the lower end portions of the fins located in the vicinity of the lowermost flat tubes are in contact with the water collection tray, and therefore, the lowermost sub heat exchange portions including the lowermost flat tubes easily radiate heat to the water collection tray. In this case, if the defrosting operation is performed, the heat exchange portion at the lowest stage is less likely to increase in temperature than the heat exchange portion at the upper stage because the sub heat exchange portion at the lowest stage radiates heat to the water collection tray, and therefore, the time required to melt the frost adhering to the heat exchange portion at the lowest stage is longer. That is, in the above-described conventional heat exchanger structure, the sub heat exchange portion including the lowermost flat tubes radiates heat to the water collection tray, and therefore, it is estimated that this is one of the reasons why the time required to melt the frost adhering to the lowermost heat exchange portion during the defrosting operation is long.
As described above, in the conventional heat exchanger, since the sub heat exchange portion at the lowermost stage includes the flat tubes at the lowermost stage, in the defrosting operation on the apparatus for air conditioning by switching between the air-warming operation and the defrosting operation, it takes more time to melt frost adhering to the heat exchange portion at the lowermost stage than to melt frost adhering to the heat exchange portion at the upper stage of the heat exchange portion at the lowermost stage.
Therefore, the heat exchanger of the present invention is different from the above-described conventional heat exchanger, and as described above, it is configured such that: in the heat exchange portion, the 1 st main heat exchange portion constituting the 1 st heat exchange portion including the lowermost flat tubes includes the lowermost flat tubes.
When the heat exchanger having such a configuration is used in an apparatus for air conditioning by switching between a heating operation and a defrosting operation, when attention is paid to the 1 st heat exchange unit, during a heating operation (when used as an evaporator of a refrigerant), a refrigerant in a gas-liquid two-phase state flows into the 1 st sub heat exchange unit, and the refrigerant in a gas-liquid two-phase state flowing into the 1 st sub heat exchange unit passes through the 1 st sub heat exchange unit and the 1 st main heat exchange unit including the lowermost flat tubes in this order, is heated, and flows out of the 1 st heat exchange unit. In the defrosting operation (when used as a radiator of the refrigerant), the refrigerant in the gaseous state flows into the 1 st main heat exchange unit, and the refrigerant in the gaseous state flowing into the 1 st main heat exchange unit passes through the 1 st main heat exchange unit and the 1 st sub heat exchange unit including the lowermost flat tubes in this order, is cooled, and flows out from the 1 st heat exchange unit. That is, at this time, during the defrosting operation, the 1 st main heat exchange portion including the lowermost flat tube is located at the upstream side position where the refrigerant flows. Therefore, at this time, the gaseous refrigerant flows into the 1 st main heat exchange portion including the lowermost flat tubes, and the liquid refrigerant staying in the 1 st sub heat exchange portion at the lowermost portion is actively heated and evaporated, whereby the temperature in the 1 st heat exchange portion at the lowermost portion can be rapidly increased.
As described above, by adopting the heat exchanger having the above-described configuration in an apparatus for air conditioning using switching between the air-warming operation and the defrosting operation, it is possible to shorten the time required for melting frost adhering to the heat exchange portion at the lowermost stage during the defrosting operation.
The heat exchanger according to claim 2 is the heat exchanger according to claim 1, wherein all of the heat exchange portions except the 1 st heat exchange portion are disposed above the 1 st heat exchange portion. Wherein, the 1 st heat exchange part is provided with a 1 st main heat exchange part below the 1 st auxiliary heat exchange part.
When the heat exchanger having such a configuration is used in an apparatus for air conditioning by switching between a heating operation and a defrosting operation, focusing on the 1 st heat exchange unit, in the heating operation (when used as an evaporator of a refrigerant), a refrigerant in a gas-liquid two-phase state flows into the 1 st sub heat exchange unit, and the refrigerant in a gas-liquid two-phase state flowing into the 1 st sub heat exchange unit passes through the 1 st sub heat exchange unit and the 1 st main heat exchange unit located below the 1 st sub heat exchange unit in this order, is heated, and flows out from the 1 st heat exchange unit. In the defrosting operation (when used as a radiator of refrigerant), the refrigerant in the gaseous state flows into the 1 st main heat exchanger, and the refrigerant in the gaseous state flowing into the 1 st main heat exchanger passes through the 1 st main heat exchanger and the 1 st sub heat exchanger located above the 1 st main heat exchanger in this order, is cooled, and flows out from the 1 st heat exchanger.
The heat exchanger according to claim 3 is the heat exchanger according to claim 2, wherein: the ratio of the number of flat tubes constituting the 1 st main heat exchange portion to the number of flat tubes constituting the 1 st sub heat exchange portion is smaller than the ratio of the number of flat tubes constituting the main heat exchange portion to the number of flat tubes constituting the sub heat exchange portion in the other heat exchange portions.
The heat exchanger according to the above-mentioned 2 nd aspect has the 1 st heat exchange unit, and the 1 st main heat exchange unit is disposed below the 1 st sub heat exchange unit, as described above. Therefore, in the apparatus for air conditioning by switching between the air-warming operation and the defrosting operation, the heat exchanger of claim 2, in which the 1 st heat exchanger functions as a so-called down-flow type evaporator in the air-warming operation (when used as an evaporator of the refrigerant), that is, the 1 st main heat exchanger disposed below the 1 st sub heat exchanger after the refrigerant passes through the 1 st sub heat exchanger, functions as a heat exchanger of the so-called down-flow type. Among these, in the downflow type evaporator, when a fluid in a gas-liquid two-phase state is sent downward, a drift of the fluid is likely to occur along with the diversion of the fluid. Therefore, when the refrigerant is sent from the flat tube constituting the 1 st sub heat exchange portion to the flat tube constituting the 1 st main heat exchange portion, the refrigerant may be unevenly flowed in the 1 st heat exchange portion along with the flow division of the refrigerant. At this time, if the ratio of the number of flat tubes constituting the 1 st main heat exchange portion to the number of flat tubes constituting the 1 st sub heat exchange portion is large, the possibility of occurrence of refrigerant drift becomes high.
Therefore, here, as described above, the 1 st heat exchange portion is set as follows: the ratio of the number of flat tubes constituting the main heat exchange portion to the number of flat tubes constituting the sub heat exchange portion is smaller than that of the other heat exchange portions.
In this case, during a heating operation (when used as an evaporator of refrigerant), when refrigerant is sent from the flat tube constituting the 1 st sub heat exchange portion to the flat tube constituting the 1 st main heat exchange portion, refrigerant drift accompanying refrigerant diversion can be suppressed.
The heat exchanger according to claim 4 is the heat exchanger according to claim 1, wherein all of the heat exchange portions except the 1 st heat exchange portion are disposed above the 1 st heat exchange portion. And the 1 st sub heat exchange unit has a 1 st upper sub heat exchange unit and a 1 st lower sub heat exchange unit below the 1 st upper sub heat exchange unit. The 1 st sub heat exchange unit has a 1 st upper main heat exchange unit connected to the 1 st upper sub heat exchange unit above the 1 st upper sub heat exchange unit; and a 1 st lower main heat exchange unit connected to the 1 st lower sub heat exchange unit below the 1 st lower sub heat exchange unit.
When the heat exchanger having such a configuration is used in an apparatus for air conditioning by switching between a heating operation and a defrosting operation, focusing on the 1 st heat exchanger, during the heating operation (when used as an evaporator of a refrigerant), the refrigerant in a gas-liquid two-phase state flows into the 1 st upper sub heat exchanger and the 1 st lower sub heat exchanger. The refrigerant in the gas-liquid two-phase state flowing into the 1 st upper side sub heat exchange portion passes through the 1 st upper side sub heat exchange portion and the 1 st upper side main heat exchange portion located above the 1 st upper side sub heat exchange portion in this order, is heated, and then flows out of the 1 st heat exchange portion. The refrigerant in the gas-liquid two-phase state flowing into the 1 st lower sub heat exchanger passes through the 1 st lower sub heat exchanger and the 1 st lower main heat exchanger located below the 1 st lower sub heat exchanger in this order, is heated, and then flows out of the 1 st heat exchanger. In the defrosting operation (used as a radiator of the refrigerant), the gaseous refrigerant flows into the 1 st upper side main heat exchange portion and the 1 st lower side main heat exchange portion. The gaseous refrigerant flowing into the 1 st upper side main heat exchanger passes through the 1 st upper side main heat exchanger, the 1 st upper side sub heat exchanger located below the 1 st upper side main heat exchanger in this order, is cooled, and then flows out of the 1 st heat exchanger. The gaseous refrigerant flowing into the 1 st lower side main heat exchange part passes through the 1 st lower side main heat exchange part and the 1 st lower side auxiliary heat exchange part located above the 1 st lower side main heat exchange part in order, is cooled, and then flows out of the 1 st heat exchange part.
The heat exchanger according to claim 5 is the heat exchanger according to claim 4, wherein: the ratio of the number of flat tubes constituting the 1 st lower side main heat exchange portion to the number of flat tubes constituting the 1 st lower side sub heat exchange portion is smaller than the ratio of the number of flat tubes constituting the 1 st upper side main heat exchange portion to the number of flat tubes constituting the 1 st upper side sub heat exchange portion.
The heat exchanger according to the above-mentioned 4 th aspect has the 1 st heat exchange unit in which the 1 st upper side sub heat exchange unit is disposed below the 1 st upper side main heat exchange unit and the 1 st lower side main heat exchange unit is disposed below the 1 st lower side sub heat exchange unit, as described above. Therefore, in the heat exchanger according to the above-mentioned 4, in the device for air conditioning by switching between the heating operation and the defrosting operation, in the 1 st heat exchanger, the 1 st lower sub heat exchanger and the 1 st lower main heat exchanger function as so-called down flow type evaporators in the heating operation (used as evaporators of the refrigerant), that is, after the refrigerant passes through the 1 st lower sub heat exchanger, the 1 st lower main heat exchanger disposed below the 1 st lower sub heat exchanger is passed through. In this case, in the downflow type evaporator, when the fluid in the gas-liquid two-phase state is sent downward, the drift of the fluid is likely to occur along with the diversion of the fluid. Therefore, when the refrigerant is sent from the flat tube constituting the 1 st lower sub heat exchange portion to the flat tube constituting the 1 st lower main heat exchange portion, the refrigerant may be unevenly flowed in the 1 st lower sub heat exchange portion and the 1 st lower main heat exchange portion due to the refrigerant being branched. At this time, if the ratio of the number of flat tubes constituting the 1 st lower side main heat exchange portion to the number of flat tubes constituting the 1 st lower side sub heat exchange portion is large, the possibility of occurrence of refrigerant drift becomes high.
Therefore, as described above, the 1 st heat exchange portion is set as follows: the ratio of the number of flat tubes constituting the 1 st lower side main heat exchange portion to the number of flat tubes constituting the 1 st lower side sub heat exchange portion is smaller than the ratio of the number of flat tubes constituting the 1 st upper side main heat exchange portion to the number of flat tubes constituting the 1 st upper side sub heat exchange portion.
In this case, during a heating operation (when used as an evaporator of refrigerant), when refrigerant is sent from the flat tube constituting the 1 st lower sub heat exchange portion to the flat tube constituting the 1 st lower main heat exchange portion, refrigerant drift accompanying refrigerant diversion can be suppressed.
The heat exchanger according to claim 6 is the heat exchanger according to any one of claims 1 to 5, wherein the heat exchange portion is disposed vertically, and the sub heat exchange portion is disposed below the main heat exchange portion in all of the heat exchange portions except the 1 st heat exchange portion.
In the case of the heat exchanger having such a configuration, in an apparatus for air conditioning by switching between the heating operation and the defrosting operation, when attention is paid to the heat exchange portion other than the 1 st heat exchange portion, in the heating operation (when used as an evaporator of the refrigerant), the refrigerant in the gas-liquid two-phase state flows into the sub heat exchange portion, and the refrigerant in the gas-liquid two-phase state flowing into the sub heat exchange portion passes through the sub heat exchange portion and the main heat exchange portion located above the sub heat exchange portion in this order, is heated, and then flows out from the heat exchange portion. In the defrosting operation (used as a radiator for the refrigerant), the gaseous refrigerant flows into the main heat exchange portion, and the gaseous refrigerant flowing into the main heat exchange portion passes through the main heat exchange portion and the sub heat exchange portion located below the main heat exchange portion in this order, is cooled, and then flows out of the heat exchange portion.
Drawings
Fig. 1 is a schematic diagram of an air conditioning apparatus using an outdoor heat exchanger as a heat exchanger according to an embodiment of the present invention.
Fig. 2 is an external perspective view of the outdoor unit.
Fig. 3 is a front view of the outdoor unit (illustrating components constituting the refrigerant circuit except the outdoor heat exchanger). Fig. 4 is a schematic perspective view of the outdoor heat exchanger.
Fig. 5 is a partially enlarged perspective view of the heat exchange part of fig. 4.
Fig. 6 is a schematic configuration diagram of an outdoor heat exchanger.
Fig. 7 is a schematic configuration table of the outdoor heat exchanger.
Fig. 8 is an enlarged view (illustrating the flow of the refrigerant during the heating operation) of fig. 6, in the vicinity of the lowermost heat exchange unit (1 st heat exchange unit).
Fig. 9 is an enlarged view of the vicinity of the lowermost heat exchange unit (1 st heat exchange unit) in fig. 6 (illustrating the flow of the refrigerant during the defrosting operation).
Fig. 10 is a schematic perspective view of a heat exchanger of a variation example in which an outdoor heat exchanger is used as a heat exchanger.
Fig. 11 is a schematic configuration diagram of an outdoor heat exchanger according to a variation example.
Fig. 12 is a summary configuration table of an outdoor heat exchanger of a variation example.
Fig. 13 is an enlarged view (illustrating the flow of the refrigerant during the heating operation) of fig. 11, in the vicinity of the lowermost heat exchange unit (1 st heat exchange unit).
Fig. 14 is an enlarged view of the vicinity of the lowermost heat exchange unit (1 st heat exchange unit) in fig. 11 (illustrating the flow of the refrigerant during the defrosting operation).
Detailed Description
Embodiments of the heat exchanger of the present invention and modified examples thereof will be explained below with reference to the drawings. The specific configuration of the heat exchanger according to the present invention is not limited to the following embodiments and modifications thereof, and may be modified without departing from the spirit of the present invention.
(1) Air conditioner structure
Fig. 1 is a schematic diagram of an air-conditioning apparatus 1 according to an embodiment of the present invention, which employs an outdoor heat exchanger 11 as a heat exchanger.
The air-conditioning apparatus 1 is an apparatus capable of performing cooling operation and heating operation in a room such as a building by a vapor compression type cooling cycle. The air conditioning apparatus 1 mainly includes: an outdoor unit 2, indoor units 3a and 3b, a liquid refrigerant connection pipe 4 and a gas refrigerant connection pipe 5 connected to the outdoor unit 2 and the indoor units 3a and 3b, and a control unit 23 for controlling devices constituting the outdoor unit 2 and the indoor units 3a and 3 b. The vapor compression type refrigerant circuit 6 of the air conditioner 1 is connected to the outdoor unit 2 and the indoor units 3a and 3b through refrigerant connection pipes 4 and 5.
The outdoor unit 2 is installed outdoors (near a building roof or a building wall) and constitutes a part of the refrigerant circuit 6. The outdoor unit 2 mainly has: 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 isolation valve 13, a gas-side isolation valve 14, and an outdoor fan 15. All the devices and the valves are connected through refrigerant pipes 16-22.
The indoor units 3a and 3b are installed indoors (behind a living room or a ceiling), 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 33 a. The indoor unit 3b mainly has: an indoor expansion valve 31b, an indoor heat exchanger 32b, and an indoor fan 33b as expansion means.
The refrigerant connection pipes 4 and 5 are refrigerant pipes that need to be constructed on site when the air-conditioning apparatus 1 is installed in an installation place such as a building. One end of the liquid refrigerant connection pipe 4 is connected to the liquid side isolation valve 13 of the indoor unit 2, and the other end of the liquid refrigerant connection pipe 4 is connected to the liquid ends of the indoor expansion valves 31a and 31b of the indoor units 3a and 3 b. One end of the gas refrigerant connection pipe 5 is connected to the gas side isolation valve 14 of the indoor unit 2, and the other end of the gas refrigerant connection pipe 5 is connected to the gas side of the indoor heat exchangers 32a and 32b of the indoor units 3a and 3 b.
The control unit 23 is connected to a control main board or the like (not shown) provided in the outdoor unit 2 or the indoor units 3a and 3b in a communication manner. In addition, the control section is far from the outdoor unit 2 and the indoor units 3a and 3b in fig. 1 for convenience. The control unit 23 controls the constituent devices 8, 10, 12, 15, 31a, 31b, 33a, and 33b of the air-conditioning apparatus 1 (here, the outdoor unit 2 or the indoor units 3a and 3b), that is, controls the overall operation of the air-conditioning apparatus 1.
(2) Operation of air conditioner
The operation of the air conditioner 1 will be described below with reference to fig. 1. The air conditioning apparatus 1 performs a cooling operation and a heating operation in which a 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 to perform the cooling operation; the refrigerant is circulated in the order of the compressor 8, the indoor heat exchangers 32a and 32b, the indoor expansion valves 31a and 31b, the outdoor expansion valve 12, and the outdoor heat exchanger 11 to perform a heating operation. A defrosting operation in which frost adhering to the outdoor heat exchanger 11 is dissolved while the air-warming operation is performed. At this time, the defrosting operation is performed by reversing the refrigerant cycle 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, as in the cooling operation. The cooling operation, the heating operation, and the defrosting operation are all executed by the control unit 23.
During the cooling operation, the four-way switching valve 10 is switched to the outdoor heat radiation state (the state indicated by the solid line in fig. 1). In the refrigerant circuit 6, a low-pressure gas refrigerant of the refrigeration cycle is sucked into the compressor 8, compressed to a high pressure of the refrigeration cycle, and discharged. The high-pressure gas refrigerant discharged from the compressor 8 is sent to the exterior heat exchanger 11 through the four-way switching valve 10. The high-pressure gas refrigerant sent to the exterior heat exchanger 11 exchanges heat with the outdoor air corresponding to the cooling source supplied from the outdoor fan 15 in the exterior heat exchanger 11 functioning as a radiator of the refrigerant to dissipate the heat, and becomes a high-pressure liquid refrigerant. The high-pressure liquid refrigerant having dissipated heat in the exterior heat exchanger 11 passes through the exterior expansion valve 12, the liquid side isolation valve 13, and the liquid refrigerant connection pipe 4, and is sent to the interior expansion valves 31a and 31 b. The refrigerant sent to the indoor expansion valves 31a and 31b is decompressed to a low pressure in the refrigeration cycle by the indoor expansion valves 31a and 31b, and becomes a low-pressure refrigerant in a gas-liquid two-phase state. 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 32 b. The low-pressure gas-liquid two-phase refrigerant sent to the indoor heat exchangers 32a and 32b exchanges heat with indoor air, which is supplied from the indoor fans 33a and 33b and serves as a heat source, in the indoor heat exchangers 32a and 32b, and evaporates. In this way, the indoor air is cooled and then supplied to the room for cooling. The low-pressure gas refrigerant evaporated in the indoor heat exchangers 32a and 32b passes through the gas refrigerant connection pipe 5, the gas side isolation valve 14, the four-way switching valve 10, and the accumulator 7, and is sucked into the compressor 8 again.
During the air-warming operation, the four-way switching valve 10 is switched to the outdoor evaporation state (the state indicated by the broken line in fig. 1). In the refrigerant circuit 6, a low-pressure gas refrigerant of the refrigeration cycle is sucked into the compressor 8, compressed to a high pressure of the refrigeration cycle, and discharged. The high-pressure gas refrigerant discharged from the compressor 8 is sent to the indoor heat exchangers 32a and 32b through the four-way switching valve 10, the gas-side isolation valve 14, and the gas refrigerant connection pipe 5. The high-pressure gas refrigerant sent to the indoor heat exchangers 32a and 32b exchanges heat with indoor air corresponding to a cooling source supplied from the indoor fans 33a and 33b in the indoor heat exchangers 32a and 32b, and radiates heat, thereby becoming a high-pressure liquid refrigerant. In this way, the indoor air is heated and then supplied to the room to perform the indoor air-warming operation. The high-pressure liquid refrigerant, which has dissipated heat in the indoor heat exchangers 32a and 32b, passes through the indoor expansion valves 31a and 31b, the liquid refrigerant connection pipe 4, and the liquid side isolation valve 13, and is sent to the outdoor expansion valve 12. The refrigerant sent to the outdoor expansion valve 12 is decompressed by the outdoor expansion valve 12 to a low pressure in the refrigeration cycle, and becomes a low-pressure refrigerant in a gas-liquid two-phase state. 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 exterior heat exchanger 11 is evaporated by heat exchange with outdoor air, which is supplied from the outdoor fan 15 and serves as a heat source, in the exterior heat exchanger 11 functioning as a radiator of the refrigerant, and becomes a low-pressure gas refrigerant. The low-pressure refrigerant evaporated by the exterior heat exchanger 11 passes through the four-way switching valve 10 and the accumulator 7, and is sucked into the compressor 8 again.
In the above-described air-warming operation, when frost is detected in the exterior heat exchanger 11 due to the refrigerant temperature in the exterior heat exchanger 11 falling below a predetermined temperature or the like, that is, when a condition for starting defrosting of the exterior heat exchanger 11 is reached, the defrosting operation is started by dissolving the frost adhering to the exterior heat exchanger 11.
The defrosting operation is the same as the cooling operation, and the four-way switching valve 22 is switched to the outdoor heat radiation state (the state shown by the solid line in fig. 1) to cause the outdoor heat exchanger 11 to function as a radiator of the refrigerant. This can dissolve frost adhering to the outdoor heat exchanger 11. The defrosting operation in the outdoor heat exchanger 11 is determined to have ended until a defrosting time set by referring to the state of the heating operation before defrosting has elapsed or until the temperature of the refrigerant in the outdoor heat exchanger 11 becomes higher than a certain temperature, and the defrosting operation is continued during this time, and then the heating operation is resumed. The flow of the refrigerant in the refrigerant circuit 10 during the defrosting operation is the same as that during the cooling operation, and therefore, the description thereof is omitted.
(3) Construction 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 (illustrating components constituting the refrigerant circuit other than the exterior 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 portions 60A to 60F of fig. 4. Fig. 6 is a schematic configuration diagram of the outdoor heat exchanger 11. Fig. 7 is a schematic configuration list of the outdoor heat exchanger 11. Fig. 8 is an enlarged view (illustrating the flow of the refrigerant during the heating operation) of the vicinity of the lowermost heat exchange portion (the 1 st heat exchange portion 60A) in fig. 6. Fig. 9 is an enlarged view of the vicinity of the lowermost heat exchange portion (the 1 st heat exchange portion 60A) in fig. 6 (illustrating the flow of the refrigerant during the defrosting operation).
< entirety >
The outdoor unit 2 is an upward-discharge type heat exchange unit that takes in air from the side surface of the casing 40 and discharges the air from the top surface of the casing 40. The outdoor unit 2 mainly includes a housing 40 having a substantially rectangular box shape, an outdoor fan 15 serving as a blower, devices 7, 8, and 11 such as a compressor and an outdoor heat exchanger, valves 10, 12 to 14 including a four-way switching valve and an outdoor expansion valve, and refrigerant circuit components constituting a part of the refrigerant circuit 6 such as refrigerant pipes 16 to 22. In the following description, unless otherwise specified, the top, bottom, left, right, front, rear, front, and rear surfaces indicate directions in which the outdoor unit 2 shown in fig. 2 is viewed from the front (left oblique front side in the drawing).
The housing 40 mainly includes a bottom frame 42 that is bridged over a pair of mounting brackets 41 extending in the left-right direction; a pillar 43 extending vertically from a corner of the bottom frame 42; a fan module 44 mounted on an upper section of the strut 43; and a front panel 45. Air inlets 40a, 40b, and 40c are formed in the side surfaces (here, the back surface and the left and right side surfaces), and an air outlet 40d is formed in the top surface.
The bottom frame 42 forms a bottom surface of the casing 40, and the outdoor heat exchanger 11 is provided on the bottom frame 42. The outdoor heat exchanger 11 is a substantially U-shaped heat exchanger in plan view, and substantially forms the back surface and the left and right side surfaces of the casing 40 toward the back surface and the left and right side surfaces of the casing 40. Meanwhile, the bottom frame 42 is connected to the lower end portion of the outdoor heat exchanger 11, and may also function as a water collecting tray for receiving the melt water generated in the outdoor heat exchanger 11 during the cooling operation or the defrosting operation.
The upper side of the outdoor heat exchanger 11 is provided with a fan module 44 which is formed higher than the upper side portions of the front, rear, and left and right side supports 43 of the casing 40 and the top surface of the casing 40. The fan module 44 is an assembly in which the outdoor fan 15 is accommodated in a box having substantially rectangular openings in the upper and lower surfaces. The top opening of the fan module 44 is an air blowing port 40d, and an air blowing grill 46 is provided in the air blowing port 40 d. The outdoor fan 15 is a blower, and is disposed in the casing 40 so as to face the air outlet 40d, and air is sucked into the casing 40 from the air inlets 40a, 40b, and 40c and discharged from the air outlet 40 d.
The front panel 45 is bridged between the front side support posts 43 to form the front surface of the housing 40.
The casing 40 accommodates therein components of the refrigerant circuit (the accumulator 7 and the compressor 8 are shown in fig. 2) other than the outdoor fan 15 and the outdoor heat exchanger 11. The compressor 8 and the accumulator 7 are provided in the bottom frame 42.
To sum up, the outdoor unit 2 has a casing 40 whose side surfaces (here, the back surface and the left and right side surfaces) form air suction ports 40a, 40b, 40c and whose top surface forms an air blowing port 40 d; and an outdoor fan 15 disposed in the casing 40 so as to face the air outlet 40 d; and an outdoor heat exchanger 11 disposed below the outdoor fan 15 in the casing 40.
< outdoor heat exchanger >
The outdoor heat exchanger 11 is a heat exchanger in which a refrigerant and outdoor air exchange heat, and mainly includes a 1 st header pipe 80, a 2 nd header pipe 90, a plurality of flat tubes 63, and a plurality of fins 64. The 1 st header assembly 80, the 2 nd header assembly 90, the flat tubes 63, and the fins 64 are made of aluminum or an aluminum alloy, and are joined to each other by brazing or the like.
The upper and lower ends of the 1 st header manifold 80 and the 2 nd header manifold 90 are both closed vertical long hollow cylindrical materials. The 1 st header 80 stands 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 2 nd header 90 stands 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 perforated tube having: a planar portion 63a oriented in a direction equal to a vertical direction which is a heat transfer surface; and a plurality of small passages 63b in which a refrigerant flows. The flat tubes 63 are arranged in a plurality in the vertical direction, and both ends thereof are connected to the 1 st header collecting pipe 80 and the 2 nd header collecting pipe 90. The fins 64 divide the space between the adjacent flat tubes 63 into a plurality of air passages for the flow of air, and form a plurality of notches 64a elongated in the water direction so as to be insertable into the plurality of flat tubes 63. The notches 64a of the fins 64 are shaped to substantially conform to the cross-sectional profile of the flat tubes 63.
In the outdoor heat exchanger 11, the plurality of flat tubes 63 are divided into a plurality of (6 in this case) heat exchange portions 60A to 60F arranged in the vertical direction. Specifically, the 1 st heat exchange unit 60A, the 2 nd heat exchange unit 60B · the 5 th heat exchange unit 60E, and the 6 th heat exchange unit 60F, which are the lowermost heat exchange units, are formed in this order from bottom to top. The 1 st heat exchange portion 60A has 21 flat tubes 63 including the lowermost flat tube 63A. The 2 nd heat exchange portion 60B has 18 flat tubes 63. The 3 rd heat exchange portion 60C has 15 flat tubes 63. The 4 th heat exchange portion 60D has 13 flat tubes 63. The 5 th heat exchange portion 60E has 11 flat tubes 63. The 6 th heat exchange portion 60F has 9 flat tubes 63.
The 1 st header tank 80 has its internal space partitioned into upper and lower spaces by a partition plate 81, thereby forming inlet and outlet communicating spaces 82A to 82F corresponding to the heat exchange portions 60A to 60F. The inlet/outlet communication spaces 82B to 82F except for the 1 st inlet/outlet communication space 82A corresponding to the 1 st heat exchange unit 60A are partitioned into upper and lower spaces by the partition plate 83, and upper gas side inlet/outlet communication spaces 84B to 84F and lower liquid side inlet/outlet communication spaces 85B to 85F are formed. The 1 st inlet/outlet communication space 82A corresponding to the 1 st heat exchange unit 60A is divided into upper and lower 3 parts by 2 partitions 86, and a 1 st upper gas side inlet/outlet communication space 84AU, a 1 st liquid side inlet/outlet communication space 85A, and a 1 st lower gas side inlet/outlet communication space 84AL are formed in this order from top to bottom. The 1 st upper gas side inlet/outlet communication space 84AU and the 1 st lower gas side inlet/outlet communication space 84AL are collectively referred to as a 1 st gas side inlet/outlet communication space 84A.
The 2 nd gas side inlet/outlet communication space 84B communicates with the upper 12 flat tubes 63 constituting the 2 nd heat exchange portion 60B, and the 2 nd liquid side inlet/outlet communication space 85B communicates with the remaining 6 flat tubes 63 among the flat tubes 63 constituting the 2 nd heat exchange portion 60B. The 3 rd gas side inlet/outlet communication space 84C communicates with the upper 10 flat tubes 63 constituting the 3 rd heat exchange portion 60C, and the 3 rd liquid side inlet/outlet communication space 85C communicates with the remaining 5 flat tubes 63 among the flat tubes 63 constituting the 3 rd heat exchange portion 60C. The 4 th gas side inlet/outlet communication space 84D communicates with the upper 9 flat tubes 63 constituting the 4 th heat exchange portion 60D, and the 4 th liquid side inlet/outlet communication space 85D communicates with the remaining 4 flat tubes 63 among the flat tubes 63 constituting the 4 th heat exchange portion 60D.
The 5 th gas side inlet/outlet communication space 84E communicates with the upper 7 flat tubes 63 constituting the 5 th heat exchange portion 60E, and the 5 th liquid side inlet/outlet communication space 85E communicates with the remaining 4 flat tubes 63 among the flat tubes 63 constituting the 5 th heat exchange portion 60E. The 6 th gas side inlet/outlet communication space 84F communicates with the upper 6 flat tubes 63 of the 6 th heat exchange portion 60F, and the 6 th liquid side inlet/outlet communication space 85F communicates with the remaining 3 flat tubes 63 of the 6 th heat exchange portion 60F. The 1 st upper gas side inlet/outlet communication space 84AU communicates with the upper 12 flat tubes 63 constituting the 1 st heat exchange portion 60A, the 1 st lower liquid side inlet/outlet communication space 84AL communicates with the lower 2 flat tubes 63 including the lowermost flat tube 63A among the flat tubes 63 constituting the 1 st heat exchange portion 60A, and the 1 st liquid side inlet/outlet communication space 85A communicates with the remaining 7 flat tubes 63 constituting the 1 st heat exchange portion 60A.
The flat tubes 63 communicating with the gas-side inlet/outlet communication spaces 84A to 84F serve as the main heat exchange portions 61A to 61F, and the flat tubes 63 communicating with the liquid-side inlet/outlet communication spaces 85A to 85F serve as the sub heat exchange portions 62A to 62F. That is, in the 2 nd inlet/outlet communication space 82B, the 2 nd gas side inlet/outlet communication space 84B communicates with the upper 12 of the flat tubes 63 constituting the 2 nd heat exchange portion 60B (the 2 nd main heat exchange portion 61B), and the 2 nd liquid side inlet/outlet communication space 85B communicates with the remaining 6 of the flat tubes 63 constituting the 2 nd heat exchange portion 60B (the 2 nd sub heat exchange portion 62B).
In the 3 rd port communication space 82C, the 3 rd gas side port communication space 84C communicates with the upper 10 of the flat tubes 63 constituting the 3 rd heat exchange portion 60C (the 3 rd main heat exchange portion 61C), and the 3 rd liquid side port communication space 85C communicates with the remaining 5 of the flat tubes 63 constituting the 3 rd heat exchange portion 60C (the 3 rd sub heat exchange portion 62C). In the 4 th port communication space 82D, the 4 th gas side port communication space 84D communicates with the upper 9 of the flat tubes 63 constituting the 4 th heat exchange portion 60D (the 4 th main heat exchange portion 61D), and the 4 th liquid side port communication space 85D communicates with the remaining 4 of the flat tubes 63 constituting the 4 th heat exchange portion 60D (the 4 th sub heat exchange portion 62D).
In the 5 th port communication space 82E, the 5 th gas side port communication space 84E communicates with the upper 7 of the flat tubes 63 constituting the 5 th heat exchange portion 60E (the 5 th main heat exchange portion 61E), and the 5 th liquid side port communication space 85E communicates with the remaining 4 of the flat tubes 63 constituting the 5 th heat exchange portion 60E (the 5 th sub heat exchange portion 62E).
In the 6 th port communication space 82F, the 6 th gas side port communication space 84F communicates with the upper 6 of the flat tubes 63 constituting the 6 th heat exchange portion 60F (the 6 th main heat exchange portion 61F), and the 6 th liquid side port communication space 85F communicates with the remaining 3 of the flat tubes 63 constituting the 6 th heat exchange portion 60F (the 6 th sub heat exchange portion 62F).
In the 1 st inlet/outlet communication space 82A, the 1 st upper gas side inlet/outlet communication space 84AU, which is one of the 1 st gas side inlet/outlet communication spaces 84A, communicates with the upper 12 of the flat tubes 63 constituting the 1 st heat exchange unit 60A (the 1 st upper main heat exchange unit 61AU, which is one of the 1 st main heat exchange units 61A).
Meanwhile, in the 1 st inlet/outlet communication space 82A, the other 1 st lower gas side inlet/outlet communication space 84AL of the 1 st gas side inlet/outlet communication space 84A communicates with the next 2 (the other 1 st lower main heat exchange portion 61AL of the 1 st main heat exchange portion 61A) of the flat tubes 63 constituting the 1 st heat exchange portion 60A.
In the 1 st inlet/outlet communication space 82A, the 1 st liquid-side inlet/outlet communication space 85A communicates with the remaining 7 flat tubes 63 constituting the 1 st heat exchange portion 60A (the 1 st sub heat exchange portion 62A).
Further, the following components are connected to the 1 st header tank 80: a liquid-side flow splitting member 70 that splits and conveys the refrigerant from the outdoor expansion valve 12 (see fig. 1) to the liquid-side inlet/outlet communication spaces 85A to 85F during the air-warming operation; and a gas-side flow splitting member 75 that splits and conveys the refrigerant from the compressor 8 (see fig. 1) to the gas-side inlet/outlet communicating spaces 84A to 84F during the cooling operation.
The liquid side flow dividing member 70 includes a liquid side refrigerant flow divider 71 connected to the refrigerant pipe 20 (see fig. 1), and liquid side refrigerant flow dividing pipes 72A to 72F extending from the liquid side refrigerant flow divider 71 and connected to the liquid side inlet/outlet communication spaces 85A to 85F. The liquid-side refrigerant flow-dividing pipes 72A to 72F each have a narrow pipe whose length and inner diameter are matched with the flow-dividing ratio to the sub heat exchange portions 62A to 62F.
The gas-side branch flow member 75 includes a gas-side refrigerant branch header pipe 76 connected to the refrigerant pipe 19 (see fig. 1), and gas-side refrigerant branch pipes 77A to 77F extending from the gas-side refrigerant branch header pipe 76 and connected to the gas-side inlet/outlet communication spaces 84A to 84F, respectively. The 1 st gas side inlet/outlet communication space 84A has a 1 st upper gas side inlet/outlet communication space 84AU and a 1 st lower gas side inlet/outlet communication space 84AL, and therefore the 1 st gas side refrigerant branch pipe 77A extending from the gas side refrigerant flow header pipe 76 also has a 1 st upper gas side refrigerant branch pipe 77AU and a 1 st lower gas side refrigerant branch pipe 77 AL.
The header 2 pipe 90 has its internal space divided into upper and lower spaces by partitions 91, thereby forming return communicating spaces 92A to 92F corresponding to the heat exchange portions 60A to 60F. Meanwhile, the 1 st turn-back communication space 92A corresponding to the 1 st heat exchange unit 60A is divided into upper and lower portions by the partition plate 93, and thus an upper 1 st upper turn-back communication space 92AU and a lower 1 st lower turn-back communication space 92AL are formed. The internal space of the 2 nd header collecting pipe 90 is not limited to the space divided by the partition plates 91 and 93 as described above, and may be other structures as long as the flow state of the refrigerant in the 2 nd header collecting pipe 90 can be maintained well.
The respective turn communication spaces 92A to 92F communicate with all the flat tubes 63 constituting the heat exchange portions 60A to 60F. That is, the 2 nd turn-around communication space 92B communicates with all of the 18 flat tubes 63 constituting the 2 nd heat exchange portion 60B. The 3 rd turn communication space 92C communicates with all of the 15 flat tubes 63 constituting the 3 rd heat exchange portion 60C. The 4 th turn communication space 92D communicates with all of the 13 flat tubes 63 constituting the 4 th heat exchange portion 60D. The 5 th turn communication space 92E communicates with all of the 11 flat tubes 63 constituting the 5 th heat exchange portion 60E. The 6 th folded communication space 92F communicates with all of the 9 flat tubes 63 constituting the 6 th heat exchange portion 60F. The 1 st turn communication space 92A communicates with all of the 21 flat tubes 63 constituting the 1 st heat exchange portion 60A. The 1 st upper folded communication space 92AU, which is an upper portion of the 1 st folded communication space 92A, communicates with 17 flat tubes 63 among the 21 flat tubes 63 constituting the 1 st heat exchange unit 60A.
Meanwhile, the 1 st lower turn communication space 92AL, which is a lower portion of the 1 st turn communication space 92A, communicates with the lower 4 of the 21 flat tubes 63 constituting the 1 st heat exchange portion 60A, including the lowermost flat tube 63A. Among these, the upper 12 flat tubes 63 out of the 17 flat tubes 63 communicating with the 1 st upper turn communication space 92AU constitute the 1 st upper main heat exchange portion 61AU which is one of the 1 st main heat exchange portions 61A, and the remaining 5 flat tubes 63 constitute the 1 st upper sub heat exchange portion 62AU which is an upper portion of the 1 st sub heat exchange portion 62A. Meanwhile, the lower 2 flat tubes 63 among the 4 flat tubes 63 communicating with the 1 st lower turn communication space 92AL include the lower 2 flat tubes 63 of the lowermost flat tube 63A, and constitute the other 1 st lower main heat exchange portion 61AL of the 1 st main heat exchange portion 61A, and the remaining 2 flat tubes 63 constitute the 1 st lower sub heat exchange portion 62AL which is the lower portion of the 1 st sub heat exchange portion 62A.
As described above, each of the heat exchange sections 60A to 60F includes the main heat exchange sections 61A to 61F; and sub heat exchange units 62A to 62F connected in series with the main heat exchange units 61A to 61F at upper and lower positions different from the main heat exchange units 61A to 61F. That is, the 2 nd heat exchange portion 60B has 12 flat tubes 63 constituting the 2 nd main heat exchange portion 61B communicating with the 2 nd gas side inlet/outlet communication space 84B; and 6 flat tubes 63 located directly below the 2 nd main heat exchange portion 61B and constituting the 2 nd sub heat exchange portion 62B communicating with the 2 nd liquid side inlet/outlet communication space 85B; the flat tubes are connected in series by the 2 nd turn-around communicating space 92B. The 3 rd heat exchange portion 60C has 10 flat tubes 63 constituting the 3 rd main heat exchange portion 61C communicating with the 3 rd gas side inlet/outlet communication space 84C; and 5 flat tubes 63 located directly below the 3 rd main heat exchange portion 61C and constituting the 3 rd sub heat exchange portion 62C communicating with the 3 rd liquid side inlet/outlet communication space 85C; the flat tubes are connected in series by the 3 rd turn-around communicating space 92C. The 4 th heat exchange portion 60D has 9 flat tubes 63 constituting the 4 th main heat exchange portion 61D communicating with the 4 th gas side inlet/outlet communication space 84D; and 4 flat tubes 63 located directly below the 4 th main heat exchange portion 61D and constituting the 4 th sub heat exchange portion 62D communicating with the 4 th liquid side inlet/outlet communication space 85D; the flat tubes are connected in series by the 4 th turn-back communication space 92D. The 5 th heat exchange portion 60E has 7 flat tubes 63 constituting the 5 th main heat exchange portion 61E communicating with the 5 th gas side inlet/outlet communication space 84E; and 4 flat tubes 63 located directly below the 5 th main heat exchange portion 61E and constituting the 5 th sub heat exchange portion 62E communicating with the 5 th liquid side inlet/outlet communication space 85E; the flat tubes are connected in series by the 5 th turn-around communicating space 92E. The 6 th heat exchange portion 60F has 6 flat tubes 63 constituting the 6 th main heat exchange portion 61F communicating with the 6 th gas side inlet/outlet communication space 84F; and 3 flat tubes 63 located directly below the 6 th main heat exchange portion 61F and constituting the 6 th sub heat exchange portion 62F communicating with the 6 th liquid side inlet/outlet communication space 85F; the flat tubes are connected in series by the 6 th turn-back communication space 92F. The 1 st heat exchange portion 60A has 14 flat tubes 63 constituting the 1 st main heat exchange portion 61A communicating with the 1 st gas side inlet/outlet communication space 84A; and 7 flat tubes 63 constituting the 1 st sub heat exchange portion 62A communicating with the 1 st liquid side inlet/outlet communication space 85A; the flat tubes are connected in series by the 1 st turn-around communicating space 92A. The 1 st heat exchange unit 60A includes two upper and lower heat exchange units 60AU and 60 AL. The 1 st upper heat exchange unit AU has 12 flat tubes 63 constituting the 1 st upper main heat exchange unit 61AU communicating with the 1 st upper gas inlet/outlet communication space 84 AU; and 5 flat tubes 63 located directly below the 1 st upper main heat exchange unit 61AU and constituting the 1 st upper sub heat exchange unit 62AU communicating with the 1 st liquid side inlet/outlet communication space 85A; the flat tubes are connected in series by the 1 st upper turn communication space 92 AU. The 1 st lower heat exchange portion AL includes 2 flat tubes 63 including the lowermost flat tube 63A constituting the 1 st lower main heat exchange portion 61AL communicating with the 1 st lower gas inlet/outlet communication space 84 AL; and 2 flat tubes 63 located directly above the 1 st lower main heat exchange portion 61AL and constituting the 1 st lower sub heat exchange portion 62AL communicating with the 1 st liquid side inlet/outlet communication space 85A; the flat tubes are connected in series by the 1 st lower turn-around communication space 92 AL.
As described above, the present invention includes a plurality of flat tubes 63 arranged vertically and having refrigerant passages 63b formed therein, and a plurality of fins 64 for partitioning spaces between adjacent flat tubes 63 into a plurality of air passages through which air flows. The flat tube 63 is divided into a plurality of heat exchange portions 60A to 60F, and each of the heat exchange portions 60A to 60F has a main heat exchange portion 61A to 61F; and sub heat exchange units 62A to 62F connected in series with the main heat exchange units 61A to 61F at upper and lower positions different from the main heat exchange units 61A to 61F. Among the plurality of heat exchange portions 60A to 60F, the 1 st main heat exchange portion 61A constituting the 1 st heat exchange portion 60A including the lowermost flat tubes 63A is configured to include the lowermost flat tubes 63A.
All the heat exchange units 60B to 60F except the 1 st heat exchange unit 60A are disposed above the 1 st heat exchange unit 60A. The 1 st sub heat exchanger 62A includes a 1 st upper sub heat exchanger 62AU and a 1 st lower sub heat exchanger 62AL below the 1 st upper sub heat exchanger 62 AU. The 1 st main heat exchanger 61A includes a 1 st upper main heat exchanger 61AU connected to the 1 st upper sub heat exchanger 62AU above the 1 st upper sub heat exchanger 62 AU; and a 1 st lower main heat exchange unit 61AL connected to the 1 st lower sub heat exchange unit 62AL below the 1 st lower sub heat exchange unit 62 AL.
The ratio of the number of flat tubes 63 (2) constituting the 1 st lower main heat exchange portion 61AL to the number of flat tubes 63 (2) constituting the 1 st lower sub heat exchange portion 62AL (2/2 is 1.0) is set as follows: the ratio of the number of flat tubes 63 (12) constituting the 1 st upper main heat exchange portion 61AU to the number of flat tubes 63 (5) constituting the 1 st upper sub heat exchange portion 62AU is smaller (12/5 is 2.4). The ratio of the number of flat tubes 63 constituting the 1 st lower main heat exchange portion 61AL to the number of flat tubes 63 constituting the 1 st lower sub heat exchange portion 62AL is not limited to 1.0, but is preferably in the range of 0.5 to 1.5. The ratio of the number of flat tubes 63 constituting the 1 st upper main heat exchange portion 61AU to the number of flat tubes 63 constituting the 1 st upper sub heat exchange portion 62AU is not limited to 2.4, but is preferably within a range of 1.7 to 3.0.
Here, the heat exchange portions 60A to 60F are arranged vertically, and the heat exchange portions 60B to 60F except for the 1 st heat exchange portion 60A are all arranged with the sub heat exchange portions 62B to 62F below the main heat exchange portions 61B to 61F.
The flow of the refrigerant in the exterior heat exchanger 11 having the above-described configuration will be described below.
During the cooling operation, the exterior heat exchanger 11 functions as a radiator, and radiates heat to 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 flow dividing member 75 through the refrigerant pipe 19 (see fig. 1). The refrigerant sent to the gas side branch member 75 is branched from the gas side refrigerant branch header pipe 76 to the gas side refrigerant branch pipes 77AU, 77AL, and 77B to 77F, and then sent to the gas side inlet/outlet communication spaces 84AU, 84AL, and 84B to 84F of the 1 st header pipe 80.
The refrigerant sent to the gas side inlet/outlet communication spaces 84AU, 84AL, 84B to 84F is branched to the flat tubes 63 of the main heat exchange portions 61AU, 61AL, 61B to 61F constituting the corresponding heat exchange portions 60AU, 60AL, 60B to 60F. The refrigerant sent to each flat tube 63 exchanges heat with outdoor air to dissipate heat while flowing through the channel 63B thereof, and is collected in each return communication space 92AU, 92AL, 92B to 92F of the 2 nd header collecting pipe 90. That is, the refrigerant passes through the main heat exchange units 61AU, 61AL, and 61B to 61F. At this time, the refrigerant radiates heat from the superheated gas state until the refrigerant transits to a gas-liquid two-phase state or a liquid state close to a saturated state.
The refrigerant collected in each of the return communication spaces 92AU, 92L, 92B to 92F is branched to the flat tubes 63 of the sub heat exchange portions 62AU, 62AL, 62B to 62F constituting the corresponding heat exchange portions 60AU, 60AL, 60B to 60F. The refrigerant sent to each flat tube 63 exchanges heat with outdoor air to dissipate heat while flowing through the passage 63b thereof, and is collected in each of the liquid side inlet/outlet communication spaces 85A to 85F of the 1 st header collecting tube 80. That is, the refrigerant passes through the sub heat exchange units 62AU, 62AL, 62B to 62F. At this time, the refrigerant starts to radiate heat from a gas-liquid two-phase state or a liquid state close to a saturated state until it transitions to a supercooled liquid state.
The refrigerant sent to the liquid side inlet/outlet communication spaces 85A to 85F is sent to the liquid side refrigerant flow dividing pipes 72A to 72F of the liquid side refrigerant flow dividing member 70, and is collected in the liquid side refrigerant flow dividing pipe 71. The refrigerant collected in the liquid-side refrigerant flow divider 71 is sent to the outdoor expansion valve 12 (see fig. 1) through the refrigerant pipe 20 (see fig. 1).
During the air-warming operation, the refrigerant decompressed by the outdoor heat exchanger 11 with respect to the outdoor expansion valve 12 (see fig. 1) functions as an evaporator.
The refrigerant decompressed by the outdoor expansion valve 12 is sent to the liquid-side refrigerant flow dividing member 70 through the refrigerant pipe 20 (see fig. 1). The refrigerant sent to the liquid-side refrigerant flow dividing member 70 is divided from the liquid-side refrigerant flow divider 71 to the liquid-side refrigerant flow dividing pipes 72A to 72F, and then sent to the liquid-side inlet/outlet communication spaces 85A to 85F of the 1 st header pipe 80.
The refrigerant sent to the liquid side inlet and outlet communication spaces 85A to 85F is branched to the flat tubes 63 of the sub heat exchange portions 62AU, 62AL, 62B to 62F constituting the corresponding heat exchange portions 60AU, 60AL, 60B to 60F. The refrigerant sent to each flat tube 63 exchanges heat with outdoor air and evaporates while flowing through the channel 63B, and is collected in each return communication space 92AU, 92AL, 92B to 92F of the 2 nd header collecting pipe 90. That is, the refrigerant passes through the sub heat exchange units 62AU, 62AL, 62B to 62F. At this time, the refrigerant starts to evaporate from a gas-liquid two-phase state with a large liquid component until the refrigerant transits to a gas-liquid two-phase state with a large gas component or a gas state close to a saturated state.
The refrigerant collected in each of the return communication spaces 92AU, 92AL, 92B to 92F is branched to the flat tubes 63 of the main heat exchange portions 61AU, 61AL, 61B to 61F constituting the corresponding heat exchange portions 60AU, 60AL, 60B to 60F. The refrigerant sent to each flat tube 63 is evaporated (heated) by heat exchange with outdoor air while flowing through the passage 63B, and is collected in each gas-side inlet/outlet communication space 84AU, 84AL, 84B to 84F of the 1 st header collecting tube 80. That is, the refrigerant passes through the main heat exchange units 61AU, 61AL, and 61B to 61F. At this time, the refrigerant starts to evaporate from a gas-liquid two-phase state or a gas state close to saturation in which the gas component is large until the refrigerant transits to a superheated gas state (is heated).
The refrigerant sent to the gas side inlet/outlet communication spaces 84AU, 84AL, and 84B to 84F is sent to the gas side refrigerant branch pipes 77AU, 77AL, and 77B to 77F of the gas side refrigerant branch member 75, and is collected in the liquid side refrigerant branch header pipe 76. The refrigerant collected in the gas-side refrigerant branch header 76 is sent to the suction side of the compressor valve 8 (see fig. 1) through the refrigerant pipe 19 (see fig. 1).
In the defrosting operation, the outdoor heat exchanger 11 functions as a radiator for the refrigerant discharged from the compressor 8 (see fig. 1) as in the cooling operation. The flow of the refrigerant in the exterior heat exchanger 11 during the defrosting operation is the same as that during the cooling operation, and therefore, the description thereof will not be repeated. However, unlike in the cooling operation, the refrigerant mainly dissolves frost adhering to the heat exchange portions 60AU, 60AL, and 60B to 60F and radiates heat at the same time in the defrosting operation.
(4) Characteristics of
The outdoor heat exchanger 11 (heat exchanger) of the present embodiment has the following features.
＜A＞
As described above, the heat exchanger 11 of the present embodiment includes the plurality of flat tubes 63 arranged in the vertical direction and having the refrigerant passages 63b formed therein, and the plurality of fins 64 partitioning the space between the adjacent flat tubes 63 into a plurality of air passages through which air flows. The flat tube 63 is divided into a plurality of heat exchange portions 60A to 60F, and each of the heat exchange portions 60A to 60F has a main heat exchange portion 61A to 61F connected to the gas side inlet and outlet communication spaces 84A to 84F; and sub heat exchange units 62A to 62F which are located at different vertical positions from the main heat exchange units 61A to 61F, are connected in series with the main heat exchange units 61A to 61F, and are connected to the liquid side inlet/outlet communication spaces 85A to 85F. Among the plurality of heat exchange portions 60A to 60F, the 1 st main heat exchange portion 61A of the 1 st heat exchange portion 60A including the lowermost flat tubes 63A is configured to include the lowermost flat tubes 63A.
In contrast, in the conventional heat exchanger, the plurality of flat tubes are divided into a plurality of heat exchange portions arranged up and down, each of the heat exchange portions having a main heat exchange portion and a sub heat exchange portion located below the main heat exchange portion and connected in series with the main heat exchange portion. Therefore, in the conventional heat exchanger, of the heat exchange portions thereof, the sub heat exchange portion constituting the lowermost heat exchange portion is configured to include the lowermost flat tube (the flat tube 63A in the present embodiment). Therefore, when the above-described conventional heat exchanger is used in an apparatus for air conditioning by switching between the air-warming operation and the defrosting operation, it takes more time to melt frost adhering to the lowermost heat exchange portion than to melt frost adhering to the upper heat exchange portion. The reason for this will be explained first.
In such a conventional configuration, when switching from the heating operation (used as a refrigerant evaporator) to the defrosting operation (used as a refrigerant radiator), the liquid-side refrigerant tends to stagnate in the lowermost sub heat exchange portion including the lowermost flat tubes. In the defrosting operation in this state, the gaseous refrigerant flows into the lowermost sub heat exchange unit after first flowing into the main heat exchange unit, and then flows into the lowermost sub heat exchange unit. That is, in the conventional heat exchanger, since the lowermost sub heat exchange portion including the lowermost flat tubes is located on the downstream side where the refrigerant flows during the defrosting operation, it is estimated that this is one of the reasons why the time required to melt the frost adhering to the lowermost heat exchange portion during the defrosting operation is long.
In the conventional configuration, when the gaseous refrigerant is branched and flows into the main heat exchange unit of each heat exchange unit during the defrosting operation, the flow rate of the gaseous refrigerant flowing into the heat exchange unit of the lowest stage is smaller than that of the heat exchange unit of the upper stage due to the influence of the refrigerant liquid head, and therefore, the time required for melting the frost adhering to the heat exchange unit of the lowest stage is longer. Further, since the level of the liquid head is affected by the height position of the flat tubes in the sub heat exchange portions constituting the heat exchange portion, if the sub heat exchange portion at the lowermost stage includes the flat tubes at the lowermost stage, the refrigerant liquid head is large, and the amount of the gaseous refrigerant flowing in during the defrosting operation is small. That is, in the conventional heat exchanger, since the flow rate of the gaseous refrigerant flowing into the lowermost heat exchange portion is decreased by the liquid head of the refrigerant during the defrosting operation, it is estimated that this is one of the reasons that the time required to melt the frost adhering to the lowermost heat exchange portion is long during the defrosting operation.
In addition, in such a conventional configuration, the lower end portions of the fins located near the lowermost flat tubes are in contact with the water collection tray (the bottom frame 42 in the present embodiment), and therefore the lowermost sub heat exchange portions including the lowermost flat tubes easily radiate heat to the water collection tray. In this case, if the defrosting operation is performed, the heat exchange portion at the lowest stage is less likely to increase in temperature than the heat exchange portion at the upper stage because the sub heat exchange portion at the lowest stage radiates heat to the water collection tray, and therefore, the time required to melt the frost adhering to the heat exchange portion at the lowest stage is longer. That is, in the conventional heat exchanger structure, the sub heat exchange portion including the lowermost flat tube radiates heat to the water collection tray, and therefore, it is estimated that this is one of the reasons why it takes a long time to melt frost adhering to the lowermost heat exchange portion during the defrosting operation.
As described above, in the conventional heat exchanger, since the sub heat exchanger at the lowermost stage includes the flat tubes at the lowermost stage, in the apparatus for air conditioning by switching between the air-warming operation and the defrosting operation, it is estimated that the time taken to melt the frost adhering to the heat exchange portion at the lowermost stage is longer than the time taken to melt the frost adhering to the heat exchange portion at the upper stage of the heat exchange portion at the lowermost stage.
Therefore, here, unlike the above-described conventional heat exchanger, as described above, it is configured such that: of the heat exchange portions 60A to 60F, the 1 st main heat exchange portion 61A of the 1 st heat exchange portion 60A including the lowermost flat tubes 63A is configured to include the lowermost flat tubes 63A.
As described above, in the heat exchanger 11 having such a configuration, when the apparatus 1 is used for air conditioning by switching between the heating operation and the defrosting operation, when attention is paid to the 1 st heat exchange portion 60A and the heating operation (when used as an evaporator of the refrigerant), as shown in fig. 8, the refrigerant in the gas-liquid two-phase state flows into the 1 st sub heat exchange portion 62A, and the refrigerant in the gas-liquid two-phase state flowing into the 1 st sub heat exchange portion 62A passes through the 1 st sub heat exchange portion 62A and the 1 st main heat exchange portion 61A including the lowermost flat tubes 63A in this order, is heated, and flows out of the 1 st heat exchange portion 60A. In the defrosting operation (when used as a radiator of the refrigerant), as shown in fig. 9, the refrigerant in the gaseous state flows into the 1 st main heat exchange portion 61A, and the refrigerant in the gaseous state flowing into the 1 st main heat exchange portion 61A passes through the 1 st main heat exchange portion 61A and the 1 st sub heat exchange portion 62A including the lowermost flat tubes 63A in this order, is cooled, and flows out from the 1 st heat exchange portion 60A. That is, at this time, during the defrosting operation, the 1 st main heat exchange portion 61A including the lowermost flat tubes 63A is located at the upstream side position in the refrigerant flow. Therefore, at this time, the gaseous refrigerant flows into the 1 st main heat exchange portion 61A including the lowermost flat tubes 63A, and the liquid refrigerant staying in the 1 st sub heat exchange portion 62A at the lowermost portion is actively heated and evaporated, whereby the temperature in the 1 st heat exchange portion 60A at the lowermost portion can be rapidly increased, and therefore, the time required for melting the frost adhering to the heat exchange portion 63A at the lowermost portion in the defrosting operation can be shortened as compared with the case of using the conventional heat exchanger.
As described above, in the apparatus 1 for air conditioning by switching between the air-warming operation and the defrosting operation, by using the heat exchanger 11 having the above-described configuration, the time required to melt frost adhering to the lowermost heat exchange portion 60A during the defrosting operation can be shortened.
＜B＞
Here, in the heat exchanger 11 of the present embodiment, as described above, all the heat exchange portions 60B to 60F except the 1 st heat exchange portion 60A are disposed above the 1 st heat exchange portion 60A. The 1 st sub heat exchanger 62A includes a 1 st upper sub heat exchanger 62AU and a 1 st lower sub heat exchanger 62AL below the 1 st upper sub heat exchanger 62 AU. The 1 st main heat exchanger 61A includes a 1 st upper main heat exchanger 61AU connected to the 1 st upper sub heat exchanger 62AU above the 1 st upper sub heat exchanger 62 AU; and a 1 st lower main heat exchange unit 61AL connected to the 1 st lower sub heat exchange unit 62AL below the 1 st lower sub heat exchange unit 62 AL.
In this configuration, when attention is paid to the 1 st heat exchange portion 60A and a heating operation (when used as an evaporator of a refrigerant) is performed, the refrigerant in a gas-liquid two-phase state flows into the 1 st upper side sub heat exchange portion 62AU and the 1 st lower side sub heat exchange portion 62AL as shown in fig. 8. The refrigerant in the gas-liquid two-phase state flowing into the 1 st upper sub heat exchanger 62AU passes through the 1 st upper sub heat exchanger 62AU and the 1 st upper main heat exchanger 61AU located above the 1 st upper sub heat exchanger 62AU in this order, is heated, and then flows out of the 1 st heat exchanger 60A. The refrigerant in the gas-liquid two-phase state flowing into the 1 st lower sub heat exchanger 62AL passes through the 1 st lower sub heat exchanger 62AL and the 1 st lower main heat exchanger 61AL located below the 1 st lower sub heat exchanger 62AL in this order, is heated, and then flows out of the 1 st heat exchanger 60A. In the defrosting operation (used as a radiator of the refrigerant), as shown in fig. 9, the refrigerant in the gaseous state flows into the 1 st upper main heat exchange unit 61AU and the 1 st lower main heat exchange unit 61 AL. The gaseous refrigerant flowing into the 1 st upper main heat exchanger 61AU passes through the 1 st upper main heat exchanger 61AU and the 1 st upper sub heat exchanger 62AU located below the 1 st upper main heat exchanger 61AU in this order to be cooled, and then flows out of the 1 st heat exchanger 60A. The gaseous refrigerant flowing into the 1 st lower main heat exchanger 61AL passes through the 1 st lower main heat exchanger 61AL and the 1 st lower sub heat exchanger 62AL located above the 1 st lower main heat exchanger 61AL in this order, is cooled, and then flows out of the 1 st heat exchanger 60A.
＜C＞
As described above, the heat exchanger 11 of the present embodiment is configured such that: the ratio of the number of flat tubes 63 constituting the 1 st lower side main heat exchange portion 61AL to the number of flat tubes 63 constituting the 1 st lower side sub heat exchange portion 62AL is smaller than the ratio of the number of flat tubes 63 constituting the 1 st upper side main heat exchange portion 61AU to the number of flat tubes 63 constituting the 1 st upper side sub heat exchange portion 62 AU.
In the above-described < B > configuration, the 1 st heat exchange unit 60A is provided, in which the 1 st upper side sub heat exchange unit 62AU is disposed below the 1 st upper side main heat exchange unit 61AU, and the 1 st lower side main heat exchange unit 61AL is disposed below the 1 st lower side sub heat exchange unit 62 AL. In the above-described configuration, during the air-warming operation (used as an evaporator of the refrigerant), as shown in fig. 8, in the 1 st heat exchange unit 60A, the 1 st lower sub heat exchange unit 62AL and the 1 st lower main heat exchange unit 61AL (the 1 st lower heat exchange unit 60AL) function as a so-called downflow type evaporator, that is, after the refrigerant passes through the 1 st lower sub heat exchange unit 62AL, the refrigerant passes through the 1 st lower main heat exchange unit 61AL disposed below the 1 st lower sub heat exchange unit 62 AL. In this case, in the downflow type evaporator, when the fluid in the gas-liquid two-phase state is sent downward, the drift of the fluid is likely to occur along with the diversion of the fluid. Therefore, when the refrigerant is sent from the flat tubes 63 constituting the 1 st lower sub heat exchange portion 62AL to the flat tubes 63 constituting the 1 st lower main heat exchange portion 61AL, the refrigerant may be unevenly flowed in the 1 st lower sub heat exchange portion 62AL and the 1 st lower main heat exchange portion 61AL in accordance with the refrigerant flow division. At this time, if the ratio of the number of flat tubes 63 constituting the 1 st lower main heat exchange portion 61AL to the number of flat tubes 63 constituting the 1 st lower sub heat exchange portion 62AL is large, the possibility of refrigerant drift is high.
Therefore, here, as described above, the 1 st heat exchange portion 60A is set as follows: the ratio of the number of flat tubes 63 constituting the 1 st lower side main heat exchange portion 61AL to the number of flat tubes 63 constituting the 1 st lower side sub heat exchange portion 62AL is smaller than the ratio of the number of flat tubes 63 constituting the 1 st upper side main heat exchange portion 61AU to the number of flat tubes 63 constituting the 1 st upper side sub heat exchange portion 62 AU. As described above, in this case, when the refrigerant is sent downward from the flat tubes 63 constituting the 1 st lower sub heat exchanger 62AL to the flat tubes 63 constituting the 1 st lower main heat exchanger 61AU during the air-warming operation (when used as an evaporator of the refrigerant), the refrigerant drift accompanying the refrigerant diversion can be suppressed.
＜D＞
In the heat exchanger 11 of the present embodiment, as described above, the heat exchange portions 60A to 60F are arranged vertically, and the heat exchange portions 60B to 60F other than the 1 st heat exchange portion 60A are all arranged with the sub heat exchange portions 62B to 62F below the main heat exchange portions 61B to 61F.
In this configuration, when attention is paid to the heat exchange portions 60B to 60F other than the 1 st heat exchange portion 60A, in the heating operation (when used as an evaporator of the refrigerant), the refrigerant in the gas-liquid two-phase state flows into the sub heat exchange portions 62B to 62F, the refrigerant in the gas-liquid two-phase state flowing into the sub heat exchange portions 62B to 62F passes through the sub heat exchange portions 62B to 62F and the main heat exchange portions 61B to 61F located above the sub heat exchange portions 62B to 62F in this order, is heated, and then flows out from the heat exchange portions 60B to 60F. In the defrosting operation (used as a radiator of the refrigerant), the gaseous refrigerant flows into the main heat exchangers 61B to 61F, and the gaseous refrigerant flowing into the main heat exchangers 61B to 61F passes through the main heat exchangers 61B to 61F and the sub heat exchangers 62B to 62F located below the main heat exchangers 61B to 61F in this order, is cooled, and then flows out from the heat exchangers 60B to 60F.
(5) Variant examples
＜A＞
In the outdoor heat exchanger 11 (heat exchanger) according to the above embodiment, the configuration in which the lowermost 1 st heat exchanger 60A including the lowermost flat tubes 63A is disposed so that the main heat exchanger 61A includes the lowermost flat tubes 63A is divided into the 1 st heat exchange portion 60A disposed so as to be the 1 st upper heat exchange portion 60AU and the 1 st lower main heat exchange portion 60AL including the lowermost flat tubes 63A (see fig. 6 to 9).
This structure is formed by providing 2 partition plates 86 in the 1 st header collecting pipe 80 to divide the 1 st inlet/outlet communication space 82A corresponding to the 1 st heat exchanging unit 60A into 3 inlet/outlet communication spaces 84AU, 85A, 84AL, and providing a partition plate 93 in the 2 nd header collecting pipe 90 to divide the 1 st return communication space 92A corresponding to the 1 st heat exchanging unit 60A into 2 return communication spaces 92AU, 92 AL. In this configuration, the 1 st upper heat exchange unit 60AU and the 1 st lower heat exchange unit 60AL are not heat exchange units independent of each other in the sense that the 1 st liquid side inlet/outlet communication space 85A and the 1 st upper heat exchange unit 60AU and the 1 st lower heat exchange unit 60AL form a common liquid side inlet/outlet communication space.
However, the configuration in which the lowermost 1 st heat exchange portion 60A including the lowermost flat tubes 63A is arranged such that the main heat exchange portion 61A includes the lowermost flat tubes 63A is not limited thereto.
For example, in the heat exchanger 11 of the above embodiment, the 1 st upper heat exchange unit 60AU and the 1 st lower heat exchange unit 60AL which are independent of each other can be formed by providing the 1 st header collecting pipe 80 with a partition plate to divide the 1 st liquid side inlet/outlet communication space 85A into two upper and lower portions and by using these as 2 liquid side inlet/outlet communication spaces.
Specifically, in the outdoor heat exchanger 11 of the present modified example, as shown in fig. 10 to 14, the plurality of flat tubes 63 are divided into a plurality of (here, 7) heat exchange portions 60A to 60G arranged vertically. Specifically, the 1 st heat exchange unit 60A, the 2 nd heat exchange unit 60B · the 6 th heat exchange unit 60F, and the 7 th heat exchange unit 60G, which are the lowermost heat exchange units, are formed in this order from bottom to top. The 1 st heat exchange portion 60A has 4 flat tubes 63 including the lowermost flat tube 63A. The 2 nd heat exchange portion 60B has 17 flat tubes 63. The 3 rd heat exchange portion 60C has 18 flat tubes 63. The 4 th heat exchange portion 60D has 15 flat tubes 63. The 5 th heat exchange portion 60E has 13 flat tubes 63. The 6 th heat exchange portion 60F has 11 flat tubes 63. The 7 th heat exchange portion 60G has 9 flat tubes 63.
The 1 st header tank 80 has its internal space partitioned into upper and lower spaces by a partition plate 81, thereby forming inlet and outlet communicating spaces 82A to 82G corresponding to the heat exchange portions 60A to 60G, respectively. The inlet and outlet communicating spaces 82A to 82G are divided into upper and lower portions by a partition plate 83. Therefore, upper gas side inlet/outlet communication spaces 84B to 84G and lower liquid side inlet/outlet communication spaces 85B to 85G are formed in the inlet/outlet communication spaces 82B to 82G excluding the 1 st inlet/outlet communication space 82A corresponding to the 1 st heat exchange unit 60A, and the upper 1 st liquid side inlet/outlet communication space 85A and the lower 1 st gas side inlet/outlet communication space 84A are formed in the 1 st inlet/outlet communication space 82A corresponding to the 1 st heat exchange unit 60A.
The 2 nd gas side inlet/outlet communication space 84B communicates with the upper 12 flat tubes 63 constituting the 2 nd heat exchange portion 60B, and the 2 nd liquid side inlet/outlet communication space 85B communicates with the remaining 5 flat tubes 63 among the flat tubes 63 constituting the 2 nd heat exchange portion 60B. The 3 rd gas side inlet/outlet communication space 84C communicates with the upper 12 flat tubes 63 constituting the 3 rd heat exchange portion 60C, and the 3 rd liquid side inlet/outlet communication space 85C communicates with the remaining 6 flat tubes 63 among the flat tubes 63 constituting the 3 rd heat exchange portion 60C. The 4 th gas side inlet/outlet communication space 84D communicates with the upper 10 flat tubes 63 constituting the 4 th heat exchange portion 60D, and the 4 th liquid side inlet/outlet communication space 85D communicates with the remaining 5 flat tubes 63 among the flat tubes 63 constituting the 4 th heat exchange portion 60D. The 5 th gas side inlet/outlet communication space 84E communicates with the upper 9 flat tubes 63 constituting the 5 th heat exchange portion 60E, and the 5 th liquid side inlet/outlet communication space 85E communicates with the remaining 4 flat tubes 63 among the flat tubes 63 constituting the 5 th heat exchange portion 60E.
The 6 th gas side inlet/outlet communication space 84F communicates with the upper 7 flat tubes 63 of the flat tubes 63 constituting the 6 th heat exchange portion 60F, and the 6 th liquid side inlet/outlet communication space 85F communicates with the remaining 4 flat tubes 63 of the flat tubes 63 constituting the 6 th heat exchange portion 60F. The 7 th gas side inlet/outlet communication space 84G communicates with the upper 6 flat tubes 63 constituting the 7 th heat exchange portion 60G, and the 7 th liquid side inlet/outlet communication space 85G communicates with the remaining 3 flat tubes 63 among the flat tubes 63 constituting the 7 th heat exchange portion 60G. The 1 st gas side inlet/outlet communication space 84A communicates with the next 2 flat tubes 63, including the lowermost flat tube 63A, among the flat tubes 63 constituting the 1 st heat exchange portion 60A, and the 1 st liquid side inlet/outlet communication space 85A communicates with the remaining 2 flat tubes 63 constituting the 1 st heat exchange portion 60A.
The flat tubes 63 communicating with the gas-side inlet/outlet communication spaces 84A to 84G serve as the main heat exchange portions 61A to 61G, and the flat tubes 63 communicating with the liquid-side inlet/outlet communication spaces 85A to 85G serve as the sub heat exchange portions 62A to 62G. That is, in the 2 nd inlet/outlet communication space 82B, the 2 nd gas side inlet/outlet communication space 84B communicates with the upper 12 of the flat tubes 63 constituting the 2 nd heat exchange portion 60B (the 2 nd main heat exchange portion 61B), and the 2 nd liquid side inlet/outlet communication space 85B communicates with the remaining 5 of the flat tubes 63 constituting the 2 nd heat exchange portion 60B (the 2 nd sub heat exchange portion 62B).
In the 3 rd port communication space 82C, the 3 rd gas side port communication space 84C communicates with the upper 12 of the flat tubes 63 constituting the 3 rd heat exchange portion 60C (the 3 rd main heat exchange portion 61C), and the 3 rd liquid side port communication space 85C communicates with the remaining 6 of the flat tubes 63 constituting the 3 rd heat exchange portion 60C (the 3 rd sub heat exchange portion 62C).
In the 4 th port communication space 82D, the 4 th gas side port communication space 84D communicates with the upper 10 of the flat tubes 63 constituting the 4 th heat exchange portion 60D (the 4 th main heat exchange portion 61D), and the 4 th liquid side port communication space 85D communicates with the remaining 5 of the flat tubes 63 constituting the 4 th heat exchange portion 60D (the 4 th sub heat exchange portion 62D).
In the 5 th port communication space 82E, the 5 th gas side port communication space 84E communicates with the upper 9 of the flat tubes 63 constituting the 5 th heat exchange portion 60E (the 5 th main heat exchange portion 61E), and the 5 th liquid side port communication space 85E communicates with the remaining 4 of the flat tubes 63 constituting the 5 th heat exchange portion 60E (the 5 th sub heat exchange portion 62E).
In the 6 th inlet/outlet communication space 82F, the 6 th gas side inlet/outlet communication space 84F communicates with the upper 7 flat tubes 63 of the flat tubes 63 constituting the 6 th heat exchange portion 60F (the 6 th main heat exchange portion 61F), and the 6 th liquid side inlet/outlet communication space 85F communicates with the remaining 4 flat tubes 63 of the flat tubes 63 constituting the 5 th heat exchange portion 60F (the 6 th sub heat exchange portion 62F).
In the 7 th port communication space 82G, the 7 th gas side port communication space 84G communicates with the upper 6 of the flat tubes 63 constituting the 7 th heat exchange portion 60G (the 7 th main heat exchange portion 61G), and the 7 th liquid side port communication space 85G communicates with the remaining 3 of the flat tubes 63 constituting the 7 th heat exchange portion 60G (the 7 th sub heat exchange portion 62G).
In the 1 st inlet/outlet communication space 82A, the 1 st gas side inlet/outlet communication space 84A communicates with the next 2 flat tubes 63 including the lowermost flat tube 63A among the flat tubes 63 constituting the 1 st heat exchange portion 60A (the 1 st main heat exchange portion 61A), and the 1 st liquid side inlet/outlet communication space 85A communicates with the remaining 2 flat tubes 63 constituting the 1 st heat exchange portion 60A (the 1 st sub heat exchange portion 62A).
Further, the following components are connected to the 1 st header tank 80: a liquid-side flow splitting member 70 that splits and conveys the refrigerant from the outdoor expansion valve 12 (see fig. 1) to the liquid-side inlet/outlet communication spaces 85A to 85G during the air-warming operation; and a gas-side flow splitting member 75 that splits and conveys the refrigerant from the compressor 8 (see fig. 1) to the gas-side inlet/outlet communication spaces 84A to 84G during the cooling operation.
The liquid side flow dividing member 70 includes a liquid side refrigerant flow divider 71 connected to the refrigerant pipe 20 (see fig. 1), and liquid side refrigerant flow dividing pipes 72A to 72G extending from the liquid side refrigerant flow divider 71 and connected to the liquid side inlet/outlet communication spaces 85A to 85G, respectively. The liquid-side refrigerant flow-dividing pipes 72A to 72G each have a narrow pipe whose length and inner diameter are matched with the flow-dividing ratio to the sub heat exchange units 62A to 62G.
The gas-side branch flow member 75 includes a gas-side refrigerant branch header pipe 76 connected to the refrigerant pipe 19 (see fig. 1), and gas-side refrigerant branch pipes 77A to 77G extending from the gas-side refrigerant branch header pipe 76 and connected to the gas-side inlet/outlet communication spaces 84A to 84G, respectively.
The header 2 pipe 90 has its internal space divided into upper and lower spaces by partitions 91, thereby forming return communicating spaces 92A to 92G corresponding to the heat exchange portions 60A to 60G, respectively. The internal space of the 2 nd header collecting pipe 90 is not limited to the space divided by the partition plate 91 as described above, and may be other structures as long as the flow state of the refrigerant in the 2 nd header collecting pipe 90 is maintained well.
The respective turn communication spaces 92A to 92G communicate with all the flat tubes 63 constituting the heat exchange portions 60A to 60G. That is, the 2 nd turn-around communication space 92B communicates with all of the 17 flat tubes 63 constituting the 2 nd heat exchange portion 60B.
The 3 rd turn communication space 92C communicates with all of the 18 flat tubes 63 constituting the 3 rd heat exchange portion 60C. The 4 th turn communication space 92D communicates with all of the 15 flat tubes 63 constituting the 4 th heat exchange portion 60D. The 5 th turn communication space 92E communicates with all of the 13 flat tubes 63 constituting the 5 th heat exchange portion 60E. The 6 th folded communication space 92F communicates with all of the 11 flat tubes 63 constituting the 6 th heat exchange portion 60F. The 7 th turn communication space 92G communicates with all of the 9 flat tubes 63 constituting the 7 th heat exchange portion 60G. The 1 st turn communication space 92A communicates with all of the 4 flat tubes 63 including the lowermost flat tube 63A constituting the 1 st heat exchange portion 60A.
As described above, each of the heat exchange sections 60A to 60G includes the main heat exchange sections 61A to 61G; and sub heat exchange units 62A to 62G connected in series with the main heat exchange units 61A to 61G at different upper and lower positions from the main heat exchange units 61A to 61G.
That is, the 2 nd heat exchange portion 60B has 12 flat tubes 63 constituting the 2 nd main heat exchange portion 61B communicating with the 2 nd gas side inlet/outlet communication space 84B; and 5 flat tubes 63 located directly below the 2 nd main heat exchange portion 61B and constituting the 2 nd sub heat exchange portion 62B communicating with the 2 nd liquid side inlet/outlet communication space 85B; the flat tubes are connected in series by the 2 nd turn-around communicating space 92B. The 3 rd heat exchange portion 60C has 12 flat tubes 63 constituting the 3 rd main heat exchange portion 61C communicating with the 3 rd gas side inlet/outlet communication space 84C; and 6 flat tubes 63 located directly below the 3 rd main heat exchange portion 61C and constituting the 3 rd sub heat exchange portion 62C communicating with the 3 rd liquid side inlet/outlet communication space 85C; the flat tubes are connected in series by the 3 rd turn-around communicating space 92C.
The 4 th heat exchange portion 60D has 10 flat tubes 63 constituting the 4 th main heat exchange portion 61D communicating with the 4 th gas side inlet/outlet communication space 84D; and 5 flat tubes 63 located directly below the 4 th main heat exchange portion 61D and constituting the 4 th sub heat exchange portion 62D communicating with the 4 th liquid side inlet/outlet communication space 85D; the flat tubes are connected in series by the 4 th turn-back communication space 92D.
The 5 th heat exchange portion 60E has 9 flat tubes 63 constituting the 5 th main heat exchange portion 61E communicating with the 5 th gas side inlet/outlet communication space 84E; and 4 flat tubes 63 located directly below the 5 th main heat exchange portion 61E and constituting the 5 th sub heat exchange portion 62E communicating with the 5 th liquid side inlet/outlet communication space 85E; the flat tubes are connected in series by the 5 th turn-around communicating space 92E.
The 6 th heat exchange portion 60F has 7 flat tubes 63 constituting the 6 th main heat exchange portion 61F communicating with the 6 th gas side inlet/outlet communication space 84F; and 4 flat tubes 63 located directly below the 6 th main heat exchange portion 61F and constituting the 6 th sub heat exchange portion 62F communicating with the 6 th liquid side inlet/outlet communication space 85F; the flat tubes are connected in series by the 6 th turn-back communication space 92F.
The 7 th heat exchange portion 60G has 6 flat tubes 63 constituting the 7 th main heat exchange portion 61G communicating with the 7 th gas side inlet/outlet communication space 84G; and 3 flat tubes 63 located directly below the 7 th main heat exchange portion 61G and constituting the 7 th sub heat exchange portion 62G communicating with the 7 th liquid side inlet/outlet communication space 85G; the flat tubes are connected in series by the 7 th turn-back communication space 92G.
The 1 st heat exchange portion 60A has 2 flat tubes 63 including the lowermost flat tube 63A constituting the 1 st main heat exchange portion 61A communicating with the 1 st lower gas side inlet/outlet communication space 84A; and 2 flat tubes 63 located directly above the 1 st main heat exchange portion 61A and constituting the 1 st sub heat exchange portion 62A communicating with the 1 st liquid side inlet/outlet communication space 85A; the flat tubes are connected in series by the 1 st turn-around communicating space 92A.
As described above, the present embodiment has the plurality of flat tubes 63 arranged vertically and having the refrigerant passages 63b formed therein, and the plurality of fins 64 dividing the space between the adjacent flat tubes 63 into the plurality of air passages through which air flows, similarly to the above-described embodiment. The flat tube 63 is divided into a plurality of heat exchange portions 60A to 60G, and each of the heat exchange portions 60A to 60G has a main heat exchange portion 61A to 61G; and sub heat exchange units 62A to 62G connected in series with the main heat exchange units 61A to 61G at upper and lower positions different from the main heat exchange units 61A to 61G. Among the plurality of heat exchange portions 60A to 60G, the 1 st main heat exchange portion 61A of the 1 st heat exchange portion 60A including the lowermost flat tubes 63A is configured to include the lowermost flat tubes 63A.
As described above, the configuration of the present modification example is similar to the above embodiment, and the time required to melt frost adhering to the lowermost heat exchange portion 60A can be shortened in the defrosting operation.
All the heat exchange units 60B to 60G except the 1 st heat exchange unit 60A are disposed above the 1 st heat exchange unit 60A. The 1 st heat exchange unit 60A is disposed below the 1 st sub heat exchange unit 62A in the 1 st main heat exchange unit 61A.
In the configuration of this modification, when attention is paid to the 1 st heat exchange portion 60A, during a heating operation (when used as an evaporator of a refrigerant), as shown in fig. 13, a refrigerant in a gas-liquid two-phase state flows into the 1 st sub heat exchange portion 62A, and a refrigerant in a gas-liquid two-phase state flowing into the 1 st sub heat exchange portion 62A passes through the 1 st sub heat exchange portion 62A and the 1 st main heat exchange portion 61A located above the 1 st sub heat exchange portion 62A in this order and is heated, and then flows out from the 1 st heat exchange portion 60A.
In the defrosting operation (when used as a radiator of the refrigerant), as shown in fig. 14, the refrigerant in the gaseous state flows into the 1 st main heat exchanger 61A, and the refrigerant in the gaseous state flowing into the 1 st main heat exchanger 61A passes through the 1 st main heat exchanger 61A and the 1 st sub heat exchanger 62A located above the 1 st main heat exchanger 61A in this order, is cooled, and flows out from the 1 st heat exchanger 60A.
In the above configuration, since the 1 st heat exchange unit 60A is provided and the 1 st main heat exchange unit 61A is disposed below the 1 st sub heat exchange unit 62A, in the same manner as in the above embodiment, during the heating operation (when used as an evaporator of the refrigerant), as shown in fig. 13, the 1 st heat exchange unit 60A functions as a so-called downflow type evaporator, that is, the 1 st main heat exchange unit 61A disposed below the 1 st sub heat exchange unit 62A after the refrigerant passes through the 1 st sub heat exchange unit 62A.
Therefore, in the 1 st heat exchange portion 60A of the present modification example, when the refrigerant is sent downward from the flat tubes 63 constituting the 1 st sub heat exchange portion 62A to the flat tubes 63 constituting the 1 st main heat exchange portion 61A, the refrigerant may be unevenly flowed along with the refrigerant being branched.
At this time, if the ratio of the number of flat tubes 63 constituting the 1 st main heat exchange portion 61A to the number of flat tubes 63 constituting the 1 st sub heat exchange portion 62A is increased, the possibility of occurrence of refrigerant drift becomes high.
Therefore, here, the ratio of the number (2) of the flat tubes 63 constituting the 1 st main heat exchange portion 61A to the number (2) of the flat tubes 63 constituting the 1 st sub heat exchange portion 62A (2/2 is 1.0) is set as follows: the ratio of the number of flat tubes 63 (6 to 12) constituting the main heat exchange portions 61A to 61G to the number of flat tubes (3 to 6) constituting the sub heat exchange portions 62B to 62G is smaller than that in the other heat exchange portions 60B to 60G (7/4 to 12/5 are 1.8 to 2.4).
The ratio of the number of flat tubes 63 constituting the 1 st main heat exchange portion 61A to the number of flat tubes 63 constituting the 1 st sub heat exchange portion 62A is not limited to 1.0, but is preferably in the range of 0.5 to 1.5. 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 not limited to 1.8 to 2.4, but is preferably in the range of 1.7 to 3.0.
As described above, in this case, similarly to the above embodiment, when the refrigerant is sent from the flat tubes 63 constituting the 1 st sub heat exchange portion 62A to the flat tubes 63 constituting the 1 st main heat exchange portion 61A during the heating operation (when used as an evaporator of the refrigerant), the refrigerant drift accompanying the refrigerant diversion can be suppressed.
＜B＞
In the above-described embodiment and modified example < a >, the present invention is applied to the outdoor heat exchanger 11 having 6 or 7 heat exchange portions, but is not limited thereto, and the number of the heat exchange portions may be less than 6 or more than 7.
The number of flat tubes 63 constituting each of the heat exchange portions 60A to 60G, and the number of division methods of the main heat exchange portions 61A to 61G and the sub heat exchange portions 62A to 62G in each of the heat exchange portions 60A to 60G are not limited to the above-described embodiment and modified example < a >.
In the above-described embodiment and modified example < a >, the present invention is applied to the outdoor heat exchanger 11 provided in the up-blowing type outdoor unit 2, but the present invention is also applied to an outdoor heat exchanger provided in another outdoor unit.
Possibility of industrial application
The present invention is widely applicable to a heat exchanger having a plurality of flat tubes arranged in a vertical direction and having a refrigerant passage formed therein, and a plurality of fins for dividing the space between the adjacent flat tubes into a plurality of air passages through which air flows.
Description of reference numerals:
11 outdoor heat exchanger (Heat exchanger)
60A-60G heat exchange unit
60A 1 st Heat exchange section
61A-61G main heat exchange unit
61A 1 st Main Heat exchange portion
61AU 1 st upper side main heat exchange unit
61AL 1 st lower main heat exchange unit
62A-62G sub heat exchange part
62A 1 st sub heat exchange unit
62AU 1 st upper side sub heat exchange unit
62AL 1 st lower side sub heat exchange part
63 flat tube
63b channel
64 fin

Claims (6)

1. A heat exchanger (11) having: a plurality of flat tubes (63) arranged vertically and having a refrigerant passage (63b) formed therein; and a plurality of fins (64) that divide the space between the adjacent flat tubes into a plurality of air passages through which air flows, the flat tubes being divided into a plurality of heat exchange portions (60A-60G), each of the heat exchange portions having: main heat exchange units (61A-61G) connected to the gas side inlet/outlet communication spaces (84A-84G); and sub heat exchange portions (62A-62G) which are located at different vertical positions from the main heat exchange portion, are connected in series with the main heat exchange portion, and are connected to liquid side inlet/outlet communication spaces (85A-85G), wherein the heat exchange portion including the flat tube at the lowermost stage is set as a 1 st heat exchange portion (60A), the main heat exchange portion and the sub heat exchange portions constituting the 1 st heat exchange portion are set as a 1 st main heat exchange portion (61A) and a 1 st sub heat exchange portion (62A), and the 1 st main heat exchange portion is disposed so as to include the flat tube at the lowermost stage.
2. The heat exchanger according to claim 1, wherein all of the heat exchange portions except the 1 st heat exchange portion are disposed above the 1 st heat exchange portion, and the 1 st heat exchange portion is disposed below the 1 st sub heat exchange portion in the 1 st main heat exchange portion.
3. The heat exchanger as claimed in claim 2, the number ratio of the flat tubes is set to: the ratio of the number of the flat tubes constituting the 1 st main heat exchange portion to the number of the flat tubes constituting the 1 st sub heat exchange portion is smaller than the ratio of the number of the flat tubes constituting the main heat exchange portion to the number of the flat tubes constituting the sub heat exchange portion in the other heat exchange portions.
4. The heat exchanger according to claim 1, wherein all of the heat exchange sections except the 1 st heat exchange section are disposed above the 1 st heat exchange section, the 1 st sub heat exchange section has a 1 st upper sub heat exchange section (62AU) and a 1 st lower sub heat exchange section (62AL) below the 1 st upper sub heat exchange section, and the 1 st main heat exchange section has a 1 st upper main heat exchange section (61AU) connected to the 1 st upper sub heat exchange section above the 1 st upper sub heat exchange section; and a 1 st lower main heat exchange unit (61AL) connected to the 1 st lower sub heat exchange unit below the 1 st lower sub heat exchange unit.
5. The heat exchanger as claimed in claim 4, wherein the number ratio of the flat tubes is set to: the ratio of the number of the flat tubes constituting the 1 st lower side main heat exchange portion to the number of the flat tubes constituting the 1 st lower side sub heat exchange portion is smaller than the ratio of the number of the flat tubes constituting the 1 st upper side main heat exchange portion to the number of the flat tubes constituting the 1 st upper side sub heat exchange portion.
6. The heat exchanger according to any one of claims 1 to 5, wherein the heat exchange units are arranged vertically, and the sub heat exchange units are arranged below the main heat exchange unit in all of the heat exchange units except the 1 st heat exchange unit.
CN201880030000.2A 2017-07-03 2018-06-27 Heat exchanger Pending CN110603421A (en)

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EP3633306A1 (en) 2020-04-08
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EP3633306A4 (en) 2020-06-03
JP2019011941A (en) 2019-01-24

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