JP2013083419A

JP2013083419A - Heat exchanger and air conditioner

Info

Publication number: JP2013083419A
Application number: JP2011280360A
Authority: JP
Inventors: Masanori Shindo; 正憲神藤; Yoshio Oritani; 好男織谷
Original assignee: Daikin Industries Ltd
Current assignee: Daikin Industries Ltd
Priority date: 2011-09-30
Filing date: 2011-12-21
Publication date: 2013-05-09

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger capable of sufficiently exerting both condensing capability and evaporative capability.SOLUTION: A plurality of flat tubes (33) are classified into a main heat exchanging part (34) and an auxiliary heat exchanging part (35) in the arrangement direction. When they function as a condenser, a refrigerant passes through the main heat exchanging part (34) and the auxiliary heat exchanging part (35) in order. When the tubes function as an evaporator, the refrigerant passes through the auxiliary heat exchanging part (35) and the main heat exchanging part (34) in order. A ratio of a super-cooling degree SC of the refrigerant flown out to header collection tubes (31, 32) from the auxiliary heat exchanging part (35) to a temperature difference ΔT between a condensing temperature of the refrigerant and an air temperature before heat exchange when the tubes function as the condenser is in a range of 20-80% and a ratio of a heat transfer area of the flat tubes (33) of the auxiliary heat exchanging part (35) to the whole heat transfer area of the plurality of the flat tubes (33) is set in 0-35%.

Description

本発明は、一対のヘッダ集合管と、各ヘッダ集合管に接続する複数の扁平管とを備え、扁平管内を流れる冷媒を空気と熱交換させる熱交換器およびそれを備えた空気調和機に関する。 The present invention relates to a heat exchanger that includes a pair of header collecting pipes and a plurality of flat pipes connected to each header collecting pipe and that exchanges heat between the refrigerant flowing in the flat pipes and air, and an air conditioner including the heat exchanger.

従来より、一対のヘッダと、各ヘッダに接続される複数の扁平管とを備えた熱交換器が知られており、例えば特許文献１に開示されている。この特許文献１の熱交換器は、冷暖可能な空気調和機に用いられている。この熱交換器は、凝縮器として機能する場合、各扁平管を流れる冷媒が空気と熱交換して凝縮し、蒸発器として機能する場合、各扁平管を流れる冷媒が空気と熱交換して蒸発する。 Conventionally, a heat exchanger including a pair of headers and a plurality of flat tubes connected to each header is known, and is disclosed in, for example, Patent Document 1. The heat exchanger of this patent document 1 is used for an air conditioner capable of cooling and heating. When this heat exchanger functions as a condenser, the refrigerant flowing through each flat tube exchanges heat with air to condense, and when it functions as an evaporator, the refrigerant flowing through each flat tube evaporates by exchanging heat with air. To do.

また、特許文献２に開示されている熱交換器は、一対のヘッダと、各ヘッダに接続される複数の扁平管とを備えて、凝縮器として機能する。この熱交換器には、凝縮用の主熱交換部と過冷却用の補助熱交換部とが形成されている。そして、この熱交換器へ流入した冷媒は、主熱交換部を通過する間に凝縮して実質的に液単相状態となり、その後に補助熱交換部へ流入してさらに冷却される。 Moreover, the heat exchanger currently disclosed by patent document 2 is equipped with a pair of header and the some flat tube connected to each header, and functions as a condenser. In this heat exchanger, a main heat exchanging part for condensation and an auxiliary heat exchanging part for supercooling are formed. Then, the refrigerant that has flowed into the heat exchanger is condensed while passing through the main heat exchanging section to be substantially in a liquid single-phase state, and thereafter flows into the auxiliary heat exchanging section to be further cooled.

特開２０１１−９４８４１号公報JP 2011-94841 A 特開２０１０−２５４４７号公報JP 2010-25447 A

ところで、上述した特許文献２の熱交換器を特許文献１のように冷暖可能な空気調和機に用いると、熱交換器は凝縮器として機能する場合と蒸発器として機能する場合とに切り換わる。この場合、全体に対する補助熱交換部の割合を単に設定すると、凝縮能力および蒸発能力を十分に発揮させることができないという問題があった。 By the way, if the heat exchanger of patent document 2 mentioned above is used for the air conditioner which can be cooled and heated like patent document 1, a heat exchanger will switch to the case where it functions as a condenser, and the case where it functions as an evaporator. In this case, there is a problem that if the ratio of the auxiliary heat exchanging part to the whole is simply set, the condensation capacity and the evaporation capacity cannot be fully exhibited.

つまり、補助熱交換部の割合が低すぎると、例えば図７（Ｅ）〜（Ｇ）に示す状態のように、補助熱交換部だけでなく主熱交換部にまで過冷却領域（液領域）が及んでしまう。そうなると、主熱交換部における液冷媒の存在によって冷媒の偏流が生じてしまう。そのため、凝縮能力が著しく低下してしまう。一方、補助熱交換部の割合が高すぎると、主熱交換部の割合が減少するため、特に蒸発器として機能する場合において空気との温度差を大きくとれる蒸発領域が実質的に減少して、その結果、蒸発能力が低下してしまう。 That is, if the ratio of the auxiliary heat exchange section is too low, for example, as shown in FIGS. 7E to 7G, the supercooling area (liquid area) extends not only to the auxiliary heat exchange section but also to the main heat exchange section. Will reach. Then, the refrigerant flow is caused by the presence of the liquid refrigerant in the main heat exchange section. As a result, the condensing capacity is significantly reduced. On the other hand, if the ratio of the auxiliary heat exchange section is too high, the ratio of the main heat exchange section is reduced, so that the evaporation region where the temperature difference from the air can be greatly reduced particularly when functioning as an evaporator, As a result, the evaporation capability is reduced.

本発明は、かかる点に鑑みてなされたものであり、その目的は、複数の扁平管が主熱交換部と補助熱交換部とに区分された熱交換器において、凝縮能力と蒸発能力の両方を十分に発揮させることにある。 The present invention has been made in view of such a point, and the object thereof is a heat exchanger in which a plurality of flat tubes are divided into a main heat exchange section and an auxiliary heat exchange section. Is to fully demonstrate.

第１の発明は、管軸と直交する方向に配列された複数の扁平管（33）と、該各扁平管（33）の両端に接続された第１ヘッダ集合管（31）および第２ヘッダ集合管（32）とを備え、冷媒が可逆に循環して冷凍サイクルを行う冷媒回路に接続されて冷媒を空気と熱交換させる熱交換器を対象としている。 The first invention includes a plurality of flat tubes (33) arranged in a direction perpendicular to the tube axis, and a first header collecting tube (31) and a second header connected to both ends of each flat tube (33). A heat exchanger that includes a collecting pipe (32) and is connected to a refrigerant circuit that circulates reversibly and performs a refrigeration cycle to exchange heat between the refrigerant and air.

そして、上記複数の扁平管（33）は、その配列方向に主熱交換部（34）と補助熱交換部（35）とに区分され、凝縮器として機能する場合は冷媒が上記主熱交換部（34）から上記補助熱交換部（35）の順に通過し、蒸発器として機能する場合は冷媒が上記補助熱交換部（35）から上記主熱交換部（34）の順に通過するように構成されている。 The plurality of flat tubes (33) are divided into a main heat exchanging portion (34) and an auxiliary heat exchanging portion (35) in the arrangement direction, and when functioning as a condenser, the refrigerant is the main heat exchanging portion. (34) through the auxiliary heat exchanger (35) in this order, and when functioning as an evaporator, the refrigerant passes through the auxiliary heat exchanger (35) through the main heat exchanger (34) in this order. Has been.

さらに、本発明の熱交換器は、凝縮器として機能する場合の冷媒の凝縮温度と熱交換前の空気の温度との温度差ΔＴに対する上記補助熱交換部（35）から上記ヘッダ集合管（31,32）へ流出した冷媒の過冷却度ＳＣの割合が２０％〜８０％の範囲で、上記複数の扁平管（33）の全体の伝熱面積に対する上記補助熱交換部（35）の扁平管（33）の伝熱面積の割合は０％よりも高く且つ３５％以下に設定されている。 Furthermore, the heat exchanger according to the present invention includes the header collecting pipe (31) from the auxiliary heat exchange part (35) to the temperature difference ΔT between the refrigerant condensing temperature and the air temperature before heat exchange when functioning as a condenser. , 32) The flat tube of the auxiliary heat exchanging part (35) with respect to the total heat transfer area of the plurality of flat tubes (33) when the ratio of the supercooling degree SC of the refrigerant flowing out to the range is 20% to 80% The ratio of the heat transfer area of (33) is set higher than 0% and 35% or less.

上記第１の発明の熱交換器では、補助熱交換部（35）の扁平管（33）の伝熱面積が主熱交換部（34）の扁平管（33）の伝熱面積よりも小さく設定され、さらに、複数の扁平管（33）の全体の伝熱面積に対する補助熱交換部（35）の扁平管（33）の伝熱面積の割合が０％よりも高く且つ３５％以下に設定されている。そのため、熱交換器が凝縮器として機能する場合、例えば図７（Ｄ）に示す状態のように、主熱交換部（34）の全体がガス領域（凝縮領域）となり、補助熱交換部（35）の全体が液領域（過冷却領域）となる。 In the heat exchanger of the first invention, the heat transfer area of the flat tube (33) of the auxiliary heat exchange part (35) is set smaller than the heat transfer area of the flat tube (33) of the main heat exchange part (34). Furthermore, the ratio of the heat transfer area of the flat tube (33) of the auxiliary heat exchange part (35) to the total heat transfer area of the plurality of flat tubes (33) is set to be higher than 0% and 35% or lower. ing. Therefore, when the heat exchanger functions as a condenser, for example, as shown in FIG. 7D, the main heat exchange part (34) as a whole becomes a gas region (condensation region), and the auxiliary heat exchange unit (35 ) Becomes the liquid region (supercooling region).

なお、ここで言う「ガス領域」とは、ガス単相の冷媒だけでなく気液二相の冷媒も含む概念であり、図７および図８における「ガス」の記載についてもガス単相だけでなく気液二相の冷媒も含む意味である。以降、説明において記載する「ガス領域」についても同様である。 The “gas region” referred to here is a concept including not only a gas single-phase refrigerant but also a gas-liquid two-phase refrigerant, and the description of “gas” in FIG. 7 and FIG. The term also includes a gas-liquid two-phase refrigerant. Hereinafter, the same applies to the “gas region” described in the description.

第２の発明は、上記第１の発明において、上記複数の扁平管（33）が、互いに同一の伝熱面積を有している。そして、本発明の熱交換器は、凝縮器として機能する場合の冷媒の凝縮温度と熱交換前の空気の温度との温度差ΔＴに対して上記補助熱交換部（35）から上記ヘッダ集合管（31,32）へ流出した冷媒の過冷却度ＳＣの割合が２０％〜８０％の範囲で、上記複数の扁平管（33）の全体本数に対する上記補助熱交換部（35）の扁平管（33）の本数の割合は０％よりも高く且つ３５％以下に設定されている。 In a second aspect based on the first aspect, the plurality of flat tubes (33) have the same heat transfer area. The heat exchanger of the present invention is configured so that the header collecting pipe is connected to the header collecting pipe from the auxiliary heat exchange section (35) with respect to a temperature difference ΔT between the refrigerant condensing temperature and the air temperature before heat exchange when functioning as a condenser. The flat tubes (35) of the auxiliary heat exchanging portion (35) with respect to the total number of the plurality of flat tubes (33) in a range where the ratio of the degree of supercooling SC of the refrigerant flowing out to (31, 32) is 20% to 80% ( The ratio of the number of 33) is set higher than 0% and 35% or less.

上記第２の発明では、全体本数に対する補助熱交換部（35）の扁平管（33）の本数の割合が所定の範囲で設定される。 In the said 2nd invention, the ratio of the number of the flat tubes (33) of the auxiliary heat exchange part (35) with respect to the whole number is set in the predetermined range.

第３の発明は、上記第１または第２の発明において、上記主熱交換部（34）および補助熱交換部（35）では、上記扁平管（33）の配列方向に、互いに複数且つ同数の熱交換領域（34a〜34c,35a〜35c）に区分されている。そして、上記第１ヘッダ集合管（31）には、その内部空間を上記扁平管（33）の配列方向に仕切ることによって、上記主熱交換部（34）の全ての熱交換領域（34a〜34c）に対応した単一の連通空間（61）と、上記補助熱交換部（35）の各熱交換領域（35a〜35c）に対応した該熱交換領域（35a〜35c）と同数の連通空間（62a〜62c）とが形成されている。また、上記第２ヘッダ集合管（32）には、その内部空間を上記扁平管（33）の配列方向に仕切ることによって、互いに隣り合う上記主熱交換部（34）の熱交換領域（34a）と上記補助熱交換部（35）の熱交換領域（35c）を除く上記両熱交換部（34,35）の各熱交換領域（34b,34c,35a,35b）に対応した該熱交換領域（34b,34c,35a,35b）と同数の連通空間（71a,71b,71d,71e）が形成されると共に、上記互いに隣り合う上記主熱交換部（34）の熱交換領域（34a）と上記補助熱交換部（35）の熱交換領域（35c）に共通に対応した単一の連通空間（71c）が形成されている。さらに、上記第２ヘッダ集合管（32）には、上記互いに隣り合う上記主熱交換部（34）の熱交換領域（34a）と上記補助熱交換部（35）の熱交換領域（35c）に共通に対応した単一の連通空間（71c）を除く上記主熱交換部（34）の各連通空間（71d,71e）と上記補助熱交換部（35）の各連通空間（71a,71b）とが各一で対となり、該対となる連通空間同士を接続する連通管（72,73）が設けられている。 According to a third invention, in the first or second invention, the main heat exchange section (34) and the auxiliary heat exchange section (35) have a plurality of and the same number in the arrangement direction of the flat tubes (33). It is divided into heat exchange regions (34a to 34c, 35a to 35c). In the first header collecting pipe (31), the internal space is partitioned in the arrangement direction of the flat pipe (33), so that all the heat exchanging regions (34a to 34c) of the main heat exchanging section (34) are formed. ) And the same number of communication spaces (35a to 35c) corresponding to the heat exchange regions (35a to 35c) of the auxiliary heat exchange section (35) ( 62a to 62c). Further, the second header collecting pipe (32) has its internal space partitioned in the arrangement direction of the flat tubes (33), so that the heat exchanging regions (34a) of the main heat exchanging portions (34) adjacent to each other are separated. And the heat exchange regions (34b, 34c, 35a, 35b) corresponding to the heat exchange regions (34b, 34c, 35a, 35b) of both the heat exchange units (34, 35) excluding the heat exchange region (35c) of the auxiliary heat exchange unit (35). 34b, 34c, 35a, 35b) and the same number of communication spaces (71a, 71b, 71d, 71e) are formed, and the heat exchange region (34a) of the main heat exchange section (34) adjacent to each other and the auxiliary A single communication space (71c) corresponding to the heat exchange region (35c) of the heat exchange section (35) is formed. Further, the second header collecting pipe (32) includes a heat exchange area (34a) of the main heat exchange section (34) adjacent to each other and a heat exchange area (35c) of the auxiliary heat exchange section (35). Each communication space (71d, 71e) of the main heat exchange part (34) excluding a single communication space (71c) corresponding to the common and each communication space (71a, 71b) of the auxiliary heat exchange part (35) Are connected to each other, and communication pipes (72, 73) for connecting the communication spaces are provided.

上記第３の発明の熱交換器では、凝縮器として機能する場合、冷媒回路から第１ヘッダ集合管（31）に流入したガス冷媒が、主熱交換部（34）の各熱交換領域（34a〜34c）へ分流して通過し、その後、第２ヘッダ集合管（32）および連通管（72,73）で折り返して補助熱交換部（35）の各熱交換領域（35a〜35c）へ流れて通過し、冷媒回路へ流出する。また、第３の発明の熱交換器では、蒸発器として機能する場合、冷媒回路から第１ヘッダ集合管（31）に流入した液冷媒が、補助熱交換器（23）の各熱交換領域（35a〜35c）を通過し、その後、第２ヘッダ集合管（32）および連通管（72,73）で折り返して主熱交換部（34）の各熱交換領域（34a〜34c）を通過し、冷媒回路へ流出する。つまり、本発明の熱交換器は、凝縮器として機能する場合も蒸発器として機能する場合も、主熱交換部（34）と補助熱交換部（35）を１回ずつ通過する。 In the heat exchanger of the third invention, when functioning as a condenser, the gas refrigerant flowing into the first header collecting pipe (31) from the refrigerant circuit is transferred to each heat exchange region (34a) of the main heat exchange section (34). To 34c), and then flows back to each heat exchange area (35a to 35c) of the auxiliary heat exchange section (35) by folding back at the second header collecting pipe (32) and the communication pipe (72, 73). Pass through and flow out into the refrigerant circuit. Moreover, in the heat exchanger of 3rd invention, when functioning as an evaporator, the liquid refrigerant which flowed into the 1st header collecting pipe (31) from the refrigerant circuit is each heat exchange area | region (23) of an auxiliary heat exchanger (23). 35a-35c), and then folded back at the second header collecting pipe (32) and the communication pipe (72, 73) and passed through each heat exchange region (34a-34c) of the main heat exchange section (34), It flows out to the refrigerant circuit. In other words, the heat exchanger of the present invention passes through the main heat exchange section (34) and the auxiliary heat exchange section (35) once, both when functioning as a condenser and as an evaporator.

第４の発明は、上記第３の発明において、上記補助熱交換部（35）では、上記各熱交換領域（35a〜35c）の扁平管（33）の総流路断面積が互いに同一である。 In a fourth aspect based on the third aspect, in the auxiliary heat exchanging portion (35), the total flow path cross-sectional areas of the flat tubes (33) of the heat exchanging regions (35a to 35c) are the same. .

上記第４の発明では、補助熱交換部（35）における各熱交換領域（35a〜35c）の扁平管（33）の総流路断面積が互いに同一であるため、各熱交換領域（35a〜35c）の冷媒の圧力損失が同等となる。例えば、補助熱交換部（35）において各扁平管（33）の流路断面積が互いに同一である場合は、補助熱交換部（35）における各熱交換領域（35a〜35c）の扁平管（33）の本数を互いに同一とすることで、各熱交換領域（35a〜35c）の扁平管（33）の総流路断面積が互いに同一となる。 In the said 4th invention, since the total flow-path cross-sectional area of the flat tube (33) of each heat exchange area | region (35a-35c) in an auxiliary heat exchange part (35) is mutually the same, each heat exchange area | region (35a- The pressure loss of the refrigerant of 35c) is equivalent. For example, when the flow passage cross-sectional areas of the flat tubes (33) are the same in the auxiliary heat exchange section (35), the flat tubes (35a to 35c) of the heat exchange regions (35a to 35c) in the auxiliary heat exchange section (35) By making the numbers of 33) the same, the total flow path cross-sectional areas of the flat tubes (33) of the respective heat exchange regions (35a to 35c) become the same.

第５の発明は、空気調和機（10）を対象とし、上記第１乃至第４の何れか一つの発明の熱交換器（23）が設けられた冷媒回路（20）を備え、上記冷媒回路（20）において冷媒を可逆に循環させて冷凍サイクルを行うものである。 A fifth invention is directed to the air conditioner (10), and includes a refrigerant circuit (20) provided with the heat exchanger (23) of any one of the first to fourth inventions, and the refrigerant circuit In (20), the refrigerant is reversibly circulated to perform a refrigeration cycle.

上記第５の発明では、上記第１乃至第４の何れか一つの発明の熱交換器（23）が冷媒回路（20）に接続される。熱交換器（23）が凝縮器として機能する場合、冷媒が主熱交換部（34）の扁平管（33）を通過した後に補助熱交換部（35）の扁平管（33）を通過し、その通過の際に冷媒は空気と熱交換して凝縮する。熱交換器（23）が蒸発器として機能する場合、冷媒が補助熱交換器（23）の扁平管（33）を通過した後に主熱交換部（34）の扁平管（33）を通過し、その通過の際に冷媒は空気と熱交換して蒸発する。 In the fifth aspect, the heat exchanger (23) of any one of the first to fourth aspects is connected to the refrigerant circuit (20). When the heat exchanger (23) functions as a condenser, the refrigerant passes through the flat tube (33) of the auxiliary heat exchange unit (35) after passing through the flat tube (33) of the main heat exchange unit (34), During the passage, the refrigerant exchanges heat with air and condenses. When the heat exchanger (23) functions as an evaporator, the refrigerant passes through the flat tube (33) of the main heat exchanger (34) after passing through the flat tube (33) of the auxiliary heat exchanger (23), During the passage, the refrigerant exchanges heat with air and evaporates.

本発明によれば、過冷却度ＳＣ／温度差ΔＴが２０％〜８０％の範囲において、複数の扁平管（33）の全体の伝熱面積に対する上記補助熱交換部（35）の扁平管（33）の伝熱面積の割合が、０％よりも高く且つ３５％以下に設定される。また、第２の発明によれば、過冷却度ＳＣ／温度差ΔＴが２０％〜８０％の範囲において、複数の扁平管（33）の全体本数に対する補助熱交換部（35）の扁平管（33）の本数の割合が、０％よりも高く且つ３５％以下に設定される。 According to the present invention, in the range where the degree of supercooling SC / temperature difference ΔT is 20% to 80%, the flat tubes (35) of the auxiliary heat exchange section (35) with respect to the entire heat transfer area of the plurality of flat tubes (33) ( The ratio of the heat transfer area of 33) is set higher than 0% and 35% or less. Moreover, according to 2nd invention, in the range whose supercooling degree SC / temperature difference (DELTA) T is 20%-80%, the flat tube (of the auxiliary heat exchange part (35) with respect to the whole number of several flat tubes (33) ( The number ratio of 33) is set higher than 0% and 35% or less.

そのため、熱交換器（23）が凝縮器として機能する場合、図７（Ｄ）に示す状態のように、主熱交換部（34）の全体がガス領域（凝縮領域）となり、補助熱交換部（35）の全体が液領域（過冷却領域）となる。これによって、必要な過冷却度ＳＣを保持して最高の凝縮能力を発揮させる一方、できるだけ高い蒸発能力を発揮させ得る熱交換器を提供することができる。つまり、凝縮能力および蒸発能力の両方を最適化し得る熱交換器を提供できる。 Therefore, when the heat exchanger (23) functions as a condenser, as shown in FIG. 7D, the entire main heat exchange part (34) becomes a gas region (condensation region), and the auxiliary heat exchange unit The whole of (35) becomes the liquid region (supercooling region). As a result, it is possible to provide a heat exchanger that can exhibit the highest condensing capacity while maintaining the necessary supercooling degree SC and at the same time exhibit the highest possible evaporation capacity. That is, it is possible to provide a heat exchanger that can optimize both the condensation capacity and the evaporation capacity.

第３の発明によれば、主熱交換部（34）の複数の熱交換領域（34a〜34c）が扁平管（33）の配列方向における片側へ集合して配列され、補助熱交換部（35）の複数の熱交換領域（35a〜35c）が反対側の片側へ集合して配列されている。これにより、互いに冷媒温度の異なる主熱交換部（34）の熱交換領域（34a〜34c）と補助熱交換部（35）の熱交換領域（35a〜35c）とが隣接する箇所を最少の１箇所に抑えることができる。そのため、互いに隣接する主熱交換部（34）の扁平管（33）と補助熱交換部（35）の扁平管（33）との間で熱が移動することによる熱ロスを最大限に抑制することができる。その結果、熱交換器（23）の熱交換効率の低下を大幅に抑制することができる。 According to the third aspect of the invention, the plurality of heat exchange regions (34a to 34c) of the main heat exchange section (34) are gathered and arranged on one side in the arrangement direction of the flat tubes (33), and the auxiliary heat exchange section (35 A plurality of heat exchange regions (35a to 35c) are gathered and arranged on one side on the opposite side. As a result, the heat exchange region (34a to 34c) of the main heat exchange unit (34) having different refrigerant temperatures and the heat exchange region (35a to 35c) of the auxiliary heat exchange unit (35) are adjacent to each other at a minimum. It can be held in place. Therefore, heat loss due to heat transfer between the flat tube (33) of the adjacent main heat exchanger (34) and the flat tube (33) of the auxiliary heat exchanger (35) is suppressed to the maximum. be able to. As a result, a decrease in the heat exchange efficiency of the heat exchanger (23) can be significantly suppressed.

第４の発明によれば、補助熱交換部（35）における各熱交換領域（35a〜35c）の扁平管（33）の総流路断面積を互いに同一としたため、各熱交換領域（35a〜35c）の冷媒の圧力損失が同等となる。ここで、熱交換器（23）全体の扁平管（33）の伝熱面積（本数）に対する補助熱交換部（35）全体の扁平管（33）の伝熱面積（本数）の割合は３５％以下と低い。そのため、熱交換器（23）全体の圧力損失は、主熱交換部（34）の圧力損失よりも補助熱交換部（35）の圧力損失が支配的となる。そのため、熱交換器（23）の冷媒の流量は、概ね補助熱交換部（35）の圧力損失に応じた流量となる。そして、本発明の補助熱交換部（35）では、上述したように各熱交換領域（35a〜35c）の圧力損失が互いに同等であるため、各熱交換領域（35a〜35c）の冷媒の流量も同等となる。これに伴い、主熱交換部（34）では、各熱交換領域（34a〜34c）の冷媒の流量も同等となる。 According to the fourth aspect of the invention, since the total cross-sectional areas of the flat tubes (33) of the heat exchange regions (35a to 35c) in the auxiliary heat exchange section (35) are the same, the heat exchange regions (35a to 35a) The pressure loss of the refrigerant of 35c) is equivalent. Here, the ratio of the heat transfer area (number) of the flat tubes (33) of the entire auxiliary heat exchanger (35) to the heat transfer area (number) of the flat tubes (33) of the entire heat exchanger (23) is 35%. Less than or below. Therefore, the pressure loss of the auxiliary heat exchange part (35) is more dominant than the pressure loss of the main heat exchange part (34). Therefore, the flow rate of the refrigerant in the heat exchanger (23) is approximately the flow rate corresponding to the pressure loss of the auxiliary heat exchange unit (35). And in the auxiliary heat exchange part (35) of this invention, since the pressure loss of each heat exchange area | region (35a-35c) is mutually equal as mentioned above, the flow volume of the refrigerant | coolant of each heat exchange area | region (35a-35c) Is equivalent. Along with this, in the main heat exchange section (34), the flow rate of the refrigerant in each heat exchange region (34a to 34c) is also equal.

これにより、例えば、主熱交換部（34）において、風速が大きい熱交換領域（34a〜34c）では風速が小さい熱交換領域（34a〜34c）よりも扁平管（33）の伝熱面積（本数）を少なくして、各熱交換領域（34a〜34c）の熱負荷を均一にすることが容易に成し得る。上述したように主熱交換部（34）の冷媒流量は補助熱交換部（35）の圧力損失に支配されることから、扁平管（33）の伝熱面積（本数）を少なくした主熱交換部（34）の熱交換領域（34a〜34c）における冷媒流量は減少するがその減少量はごく僅かとなる。したがって、主熱交換部（34）において各熱交換領域（34a〜34c）の冷媒流量は概ね同等のまま維持される。このように、風速分布に応じて主熱交換部（34）の各熱交換領域（34a〜34c）の熱負荷を均一にする際、各熱交換領域（34a〜34c）の冷媒流量のバランスをそれ程崩すことなく（各熱交換領域（34a〜34c）の冷媒流量にそれ程影響を及ぼすことなく）成し得るので、熱負荷を均一にする設計が容易となる。 Thereby, for example, in the main heat exchanging part (34), the heat transfer area (number) of the flat tubes (33) in the heat exchange area (34a to 34c) with a high wind speed is smaller than the heat exchange area (34a to 34c) with a low wind speed. ) And the heat load in each heat exchange region (34a to 34c) can be easily made uniform. As described above, since the refrigerant flow rate in the main heat exchanging section (34) is governed by the pressure loss in the auxiliary heat exchanging section (35), the main heat exchange in which the heat transfer area (number) of the flat tubes (33) is reduced. The refrigerant flow rate in the heat exchange region (34a to 34c) of the section (34) decreases, but the amount of decrease is negligible. Therefore, the refrigerant flow rates in the heat exchange regions (34a to 34c) are maintained substantially the same in the main heat exchange section (34). As described above, when the heat load of each heat exchange region (34a to 34c) of the main heat exchange unit (34) is made uniform according to the wind speed distribution, the refrigerant flow rate balance of each heat exchange region (34a to 34c) is balanced. Since it can be achieved without much disruption (without significantly affecting the refrigerant flow rate in each of the heat exchange regions (34a to 34c)), it is easy to design a uniform heat load.

第５の発明によれば、冷房能力および暖房能力の両方を十分に稼げる空気調和機を提供することができる。 According to 5th invention, the air conditioner which can fully earn both a cooling capability and a heating capability can be provided.

図１は、実施形態に係る空気調和機の冷媒回路図である。FIG. 1 is a refrigerant circuit diagram of an air conditioner according to an embodiment. 図２は、実施形態に係る室外熱交換器の正面を示す一部断面図である。Drawing 2 is a partial sectional view showing the front of the outdoor heat exchanger concerning an embodiment. 図３は、図２のIII−III断面の一部を示す熱交換器の断面図である。FIG. 3 is a cross-sectional view of the heat exchanger showing a part of the III-III cross section of FIG. 2. 図４は、過冷却度ＳＣ／温度差ΔＴと補助熱交割合の関係を示すグラフである。FIG. 4 is a graph showing the relationship between the degree of supercooling SC / temperature difference ΔT and the auxiliary heat exchange rate. 図５は、補助熱交割合と凝縮能力の関係を示すグラフである。FIG. 5 is a graph showing the relationship between the auxiliary heat exchange rate and the condensation capacity. 図６は、過冷却度ＳＣと凝縮能力の関係を示すグラフである。FIG. 6 is a graph showing the relationship between the degree of supercooling SC and the condensation capacity. 図７（Ａ）〜（Ｇ）は、室外熱交換器におけるガス領域と液領域の状態を示す模式図である。FIGS. 7A to 7G are schematic views showing the states of the gas region and the liquid region in the outdoor heat exchanger. 図８は、実施形態の変形例に係る室外熱交換器の概略構成を示す正面図である。Drawing 8 is a front view showing a schematic structure of an outdoor heat exchanger concerning a modification of an embodiment. 図９は、実施形態の変形例に係る室外熱交換器の正面を示す一部断面図である。FIG. 9 is a partial cross-sectional view showing the front of an outdoor heat exchanger according to a modification of the embodiment.

以下、本発明の実施形態を図面に基づいて詳細に説明する。なお、以下の実施形態および変形例は、本質的に好ましい例示であって、本発明、その適用物、あるいはその用途の範囲を制限することを意図するものではない。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the following embodiments and modifications are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

本実施形態の熱交換器は、空気調和機（10）に設けられた室外熱交換器（23）である。 The heat exchanger of this embodiment is an outdoor heat exchanger (23) provided in the air conditioner (10).

〈空気調和機の構成〉
空気調和機（10）について、図１を参照しながら説明する。 <Configuration of air conditioner>
The air conditioner (10) will be described with reference to FIG.

空気調和機（10）は、室外ユニット（11）および室内ユニット（12）を備えている。室外ユニット（11）と室内ユニット（12）は、液側連絡配管（13）およびガス側連絡配管（14）を介して互いに接続されている。空気調和機（10）では、室外ユニット（11）、室内ユニット（12）、液側連絡配管（13）およびガス側連絡配管（14）によって、冷媒回路（20）が形成されている。 The air conditioner (10) includes an outdoor unit (11) and an indoor unit (12). The outdoor unit (11) and the indoor unit (12) are connected to each other via a liquid side connecting pipe (13) and a gas side connecting pipe (14). In the air conditioner (10), a refrigerant circuit (20) is formed by the outdoor unit (11), the indoor unit (12), the liquid side communication pipe (13), and the gas side communication pipe (14).

冷媒回路（20）には、圧縮機（21）と、四方切換弁（22）と、室外熱交換器（23）と、膨張弁（24）と、室内熱交換器（25）とが設けられている。圧縮機（21）、四方切換弁（22）、室外熱交換器（23）、および膨張弁（24）は、室外ユニット（11）に収容されている。室外ユニット（11）には、室外熱交換器（23）へ室外空気を供給するための室外ファン（15）が設けられている。一方、室内熱交換器（25）は、室内ユニット（12）に収容されている。室内ユニット（12）には、室内熱交換器（25）へ室内空気を供給するための室内ファン（16）が設けられている。 The refrigerant circuit (20) is provided with a compressor (21), a four-way switching valve (22), an outdoor heat exchanger (23), an expansion valve (24), and an indoor heat exchanger (25). ing. The compressor (21), the four-way switching valve (22), the outdoor heat exchanger (23), and the expansion valve (24) are accommodated in the outdoor unit (11). The outdoor unit (11) is provided with an outdoor fan (15) for supplying outdoor air to the outdoor heat exchanger (23). On the other hand, the indoor heat exchanger (25) is accommodated in the indoor unit (12). The indoor unit (12) is provided with an indoor fan (16) for supplying room air to the indoor heat exchanger (25).

冷媒回路（20）は、冷媒が充填された閉回路である。冷媒回路（20）において、圧縮機（21）は、その吐出側が四方切換弁（22）の第１のポートに、その吸入側が四方切換弁（22）の第２のポートに、それぞれ接続されている。また、冷媒回路（20）では、四方切換弁（22）の第３のポートから第４のポートへ向かって順に、室外熱交換器（23）と、膨張弁（24）と、室内熱交換器（25）とが配置されている。 The refrigerant circuit (20) is a closed circuit filled with a refrigerant. In the refrigerant circuit (20), the compressor (21) has its discharge side connected to the first port of the four-way switching valve (22) and its suction side connected to the second port of the four-way switching valve (22). Yes. In the refrigerant circuit (20), the outdoor heat exchanger (23), the expansion valve (24), and the indoor heat exchanger are sequentially arranged from the third port to the fourth port of the four-way switching valve (22). (25) and are arranged.

圧縮機（21）は、スクロール型またはロータリ型の全密閉型圧縮機である。四方切換弁（22）は、第１のポートが第３のポートと連通し且つ第２のポートが第４のポートと連通する第１状態（図１に破線で示す状態）と、第１のポートが第４のポートと連通し且つ第２のポートが第３のポートと連通する第２状態（図１に実線で示す状態）とに切り換わる。膨張弁（24）は、いわゆる電子膨張弁である。 The compressor (21) is a scroll type or rotary type hermetic compressor. The four-way switching valve (22) has a first state (state indicated by a broken line in FIG. 1) in which the first port communicates with the third port and the second port communicates with the fourth port, The port is switched to a second state (state indicated by a solid line in FIG. 1) in which the port communicates with the fourth port and the second port communicates with the third port. The expansion valve (24) is a so-called electronic expansion valve.

室外熱交換器（23）は、冷媒を室外空気と熱交換させる。室外熱交換器（23）については後述する。一方、室内熱交換器（25）は、冷媒を室内空気と熱交換させる。室内熱交換器（25）は、円管である伝熱管を備えたいわゆるクロスフィン型のフィン・アンド・チューブ熱交換器によって構成されている。 The outdoor heat exchanger (23) exchanges heat between the refrigerant and the outdoor air. The outdoor heat exchanger (23) will be described later. On the other hand, the indoor heat exchanger (25) exchanges heat between the refrigerant and room air. The indoor heat exchanger (25) is constituted by a so-called cross fin type fin-and-tube heat exchanger provided with a heat transfer tube which is a circular tube.

〈空気調和機の運転動作〉
空気調和機（10）は、冷房運転と暖房運転を選択的に行う。 <Operation of air conditioner>
The air conditioner (10) selectively performs a cooling operation and a heating operation.

冷房運転中の冷媒回路（20）では、四方切換弁（22）を第１状態に設定した状態で、冷凍サイクルが行われる。この状態では、室外熱交換器（23）、膨張弁（24）、室内熱交換器（25）の順に冷媒が循環し、室外熱交換器（23）が凝縮器として機能し、室内熱交換器（25）が蒸発器として機能する。室外熱交換器（23）では、圧縮機（21）から流入したガス冷媒が室外空気へ放熱して凝縮し、凝縮後の冷媒が膨張弁（24）へ向けて流出してゆく。 In the refrigerant circuit (20) during the cooling operation, the refrigeration cycle is performed with the four-way switching valve (22) set to the first state. In this state, the refrigerant circulates in the order of the outdoor heat exchanger (23), the expansion valve (24), and the indoor heat exchanger (25), and the outdoor heat exchanger (23) functions as a condenser. (25) functions as an evaporator. In the outdoor heat exchanger (23), the gas refrigerant flowing from the compressor (21) dissipates heat to the outdoor air and condenses, and the condensed refrigerant flows out toward the expansion valve (24).

暖房運転中の冷媒回路（20）では、四方切換弁（22）を第２状態に設定した状態で、冷凍サイクルが行われる。この状態では、室内熱交換器（25）、膨張弁（24）、室外熱交換器（23）の順に冷媒が循環し、室内熱交換器（25）が凝縮器として機能し、室外熱交換器（23）が蒸発器として機能する。室外熱交換器（23）には、膨張弁（24）を通過する際に膨張して気液二相状態となった冷媒が流入する。室外熱交換器（23）へ流入した冷媒は、室外空気から吸熱して蒸発し、その後に圧縮機（21）へ向けて流出してゆく。 In the refrigerant circuit (20) during the heating operation, the refrigeration cycle is performed with the four-way switching valve (22) set to the second state. In this state, the refrigerant circulates in the order of the indoor heat exchanger (25), the expansion valve (24), and the outdoor heat exchanger (23), and the indoor heat exchanger (25) functions as a condenser. (23) functions as an evaporator. The refrigerant that has expanded into the gas-liquid two-phase state flows into the outdoor heat exchanger (23) when passing through the expansion valve (24). The refrigerant that has flowed into the outdoor heat exchanger (23) absorbs heat from the outdoor air and evaporates, and then flows out toward the compressor (21).

〈室外熱交換器の構成〉
室外熱交換器（23）について、図２〜４を適宜参照しながら説明する。なお、以下の説明に示す扁平管（33）の本数は、何れも単なる一例である。 <Configuration of outdoor heat exchanger>
The outdoor heat exchanger (23) will be described with reference to FIGS. Note that the number of flat tubes (33) shown in the following description is merely an example.

図２および図３に示すように、室外熱交換器（23）は、一つの第１ヘッダ集合管（31）と、一つの第２ヘッダ集合管（32）と、複数の扁平管（33）と、多数のフィン（36）とを備えている。第１ヘッダ集合管（31）、第２ヘッダ集合管（32）、扁平管（33）およびフィン（36）は、何れもアルミニウム合金製の部材であって、互いにロウ付けによって接合されている。 As shown in FIGS. 2 and 3, the outdoor heat exchanger (23) includes one first header collecting pipe (31), one second header collecting pipe (32), and a plurality of flat tubes (33). And a large number of fins (36). The first header collecting pipe (31), the second header collecting pipe (32), the flat pipe (33), and the fin (36) are all made of an aluminum alloy and are joined to each other by brazing.

第１ヘッダ集合管（31）と第２ヘッダ集合管（32）は、何れも両端が閉塞された細長い中空円筒状に形成されている。図２では、室外熱交換器（23）の左端に第１ヘッダ集合管（31）が立設され、室外熱交換器（23）の右端に第２ヘッダ集合管（32）が立設されている。つまり、第１ヘッダ集合管（31）と第２ヘッダ集合管（32）は、それぞれの軸方向が上下方向となる状態で設置されている。 Each of the first header collecting pipe (31) and the second header collecting pipe (32) is formed in an elongated hollow cylindrical shape whose both ends are closed. In FIG. 2, the first header collecting pipe (31) is erected at the left end of the outdoor heat exchanger (23), and the second header collecting pipe (32) is erected at the right end of the outdoor heat exchanger (23). Yes. That is, the first header collecting pipe (31) and the second header collecting pipe (32) are installed in a state where the respective axial directions are in the vertical direction.

図３にも示すように、扁平管（33）は、その断面形状が扁平な長円形あるいは角の丸い矩形となった伝熱管である。室外熱交換器（23）において、複数の扁平管（33）は、その伸長方向が左右方向となり、それぞれの平坦な側面が対向する状態で配置されている。また、複数の扁平管（33）は、互いに一定の間隔をおいて上下に並んで配置され、それぞれの伸長方向が実質的に平行になっている。つまり、複数の扁平管（33）は、管軸と直交する方向に配列されている。図２に示すように、各扁平管（33）は、その一端が第１ヘッダ集合管（31）に挿入され、その他端が第２ヘッダ集合管（32）に挿入されている。 As shown also in FIG. 3, the flat tube (33) is a heat transfer tube whose cross-sectional shape is a flat oval or a rounded rectangle. In the outdoor heat exchanger (23), the plurality of flat tubes (33) are arranged in a state in which the extending direction is the left-right direction and the respective flat side surfaces face each other. In addition, the plurality of flat tubes (33) are arranged side by side at regular intervals and their extending directions are substantially parallel to each other. That is, the plurality of flat tubes (33) are arranged in a direction orthogonal to the tube axis. As shown in FIG. 2, each flat tube (33) has one end inserted into the first header collecting tube (31) and the other end inserted into the second header collecting tube (32).

図３に示すように、各扁平管（33）には、複数の流体通路（33a）が形成されている。各流体通路（33a）は、扁平管（33）の伸長方向に延びる通路である。各扁平管（33）において、複数の流体通路（33a）は、扁平管（33）の伸長方向と直交する幅方向に一列に並んでいる。各扁平管（33）に形成された複数の流体通路（33a）は、それぞれの一端が第１ヘッダ集合管（31）の内部空間に連通し、それぞれの他端が第２ヘッダ集合管（32）の内部空間に連通している。室外熱交換器（23）へ供給された冷媒は、扁平管（33）の流体通路（33a）を流れる間に空気と熱交換する。 As shown in FIG. 3, a plurality of fluid passages (33a) are formed in each flat tube (33). Each fluid passage (33a) is a passage extending in the extending direction of the flat tube (33). In each flat tube (33), the plurality of fluid passages (33a) are arranged in a line in the width direction orthogonal to the extending direction of the flat tube (33). One end of each of the plurality of fluid passages (33a) formed in each flat tube (33) communicates with the internal space of the first header collecting pipe (31), and the other end of each of the plurality of fluid passages (33a) is the second header collecting pipe (32). ). The refrigerant supplied to the outdoor heat exchanger (23) exchanges heat with air while flowing through the fluid passage (33a) of the flat tube (33).

図３に示すように、フィン（36）は、金属板をプレス加工することによって形成された縦長の板状フィンである。フィン（36）には、フィン（36）の前縁（即ち、風上側の縁部）からフィン（36）の幅方向に延びる細長い切欠き部（45）が、多数形成されている。フィン（36）では、多数の切欠き部（45）が、フィン（36）の長手方向（上下方向）に一定の間隔で形成されている。切欠き部（45）の風下寄りの部分は、管挿入部（46）を構成している。管挿入部（46）は、上下方向の幅が扁平管（33）の厚さと実質的に等しく、長さが扁平管（33）の幅と実質的に等しい。扁平管（33）は、フィン（36）の管挿入部（46）に挿入され、管挿入部（46）の周縁部とロウ付けによって接合される。また、フィン（36）には、伝熱を促進するためのルーバー（40）が形成されている。そして、複数のフィン（36）は、扁平管（33）の伸長方向に配列されることで、隣り合う扁平管（33）の間を空気が流れる複数の通風路（37）に区画している。 As shown in FIG. 3, the fin (36) is a vertically long plate-like fin formed by pressing a metal plate. The fin (36) is formed with a number of elongated notches (45) extending in the width direction of the fin (36) from the front edge (ie, the windward edge) of the fin (36). In the fin (36), a large number of notches (45) are formed at regular intervals in the longitudinal direction (vertical direction) of the fin (36). The portion closer to the lee of the notch (45) constitutes the tube insertion portion (46). The tube insertion portion (46) has a vertical width substantially equal to the thickness of the flat tube (33) and a length substantially equal to the width of the flat tube (33). The flat tube (33) is inserted into the tube insertion portion (46) of the fin (36) and joined to the peripheral portion of the tube insertion portion (46) by brazing. Moreover, the louver (40) for promoting heat transfer is formed in the fin (36). The plurality of fins (36) are arranged in the extending direction of the flat tube (33), thereby partitioning between the adjacent flat tubes (33) into a plurality of ventilation paths (37) through which air flows. .

図２に示すように、室外熱交換器（23）の扁平管（33）は、上下に二つの熱交換部（34,35）に区分されている。具体的に、室外熱交換器（23）において、複数の扁平管（33）は、その配列方向（上下方向）に上側の主熱交換部（34）と下側の補助熱交換部（35）とに区分されている。補助熱交換部（35）は、室外熱交換器（23）が凝縮器として機能する際、冷媒を過冷却する役割を担っている。 As shown in FIG. 2, the flat tube (33) of the outdoor heat exchanger (23) is divided into two heat exchange parts (34, 35) in the vertical direction. Specifically, in the outdoor heat exchanger (23), the plurality of flat tubes (33) include an upper main heat exchange section (34) and a lower auxiliary heat exchange section (35) in the arrangement direction (vertical direction). It is divided into and. The auxiliary heat exchanger (35) plays a role of supercooling the refrigerant when the outdoor heat exchanger (23) functions as a condenser.

第１ヘッダ集合管（31）の内部空間は、１つの仕切板（39）によって、上下に２つの連通空間（31a,31b）に仕切られている。具体的に、第１ヘッダ集合管（31）の内部空間は、主熱交換部（34）の扁平管（33）に対応した（連通した）単一の上側連通空間（31a）と、補助熱交換部（35）の扁平管（33）に対応した（連通した）単一の下側連通空間（31b）とに仕切られている。つまり、室外熱交換器（23）では、第１ヘッダ集合管（31）の仕切板（39）の位置が、主熱交換部（34）と補助熱交換部（35）の境界部（55）となっている。一方、第２ヘッダ集合管（32）の内部空間は、仕切られておらず、主熱交換部（34）および補助熱交換部（35）の全ての扁平管（33）に共通に対応した（連通した）単一の連通空間（32a）である。 The internal space of the first header collecting pipe (31) is partitioned into two communicating spaces (31a, 31b) up and down by one partition plate (39). Specifically, the internal space of the first header collecting pipe (31) includes a single upper communication space (31a) corresponding to (in communication with) the flat pipe (33) of the main heat exchange section (34), and auxiliary heat. It is partitioned into a single lower communication space (31b) corresponding to (in communication with) the flat tube (33) of the exchange part (35). That is, in the outdoor heat exchanger (23), the position of the partition plate (39) of the first header collecting pipe (31) is the boundary part (55) between the main heat exchange part (34) and the auxiliary heat exchange part (35). It has become. On the other hand, the internal space of the second header collecting pipe (32) is not partitioned and corresponds to all the flat pipes (33) of the main heat exchange part (34) and the auxiliary heat exchange part (35) ( It is a single communication space (32a).

図２に示すように、室外熱交換器（23）には、ガス側接続管（51）と液側接続管（52）とが設けられている。ガス側接続管（51）および液側接続管（52）は、第１ヘッダ集合管（31）に取り付けられている。 As shown in FIG. 2, the outdoor heat exchanger (23) is provided with a gas side connection pipe (51) and a liquid side connection pipe (52). The gas side connection pipe (51) and the liquid side connection pipe (52) are attached to the first header collecting pipe (31).

ガス側接続管（51）は、比較的大径の配管で構成されている。ガス側接続管（51）の一端は、室外熱交換器（23）と四方切換弁（22）の第３のポートを繋ぐ配管と接続されている。ガス側接続管（51）の他端は、第１ヘッダ集合管（31）における上側連通空間（31a）の上端寄りの部分に開口している。 The gas side connection pipe (51) is constituted by a relatively large diameter pipe. One end of the gas side connection pipe (51) is connected to a pipe connecting the outdoor heat exchanger (23) and the third port of the four-way switching valve (22). The other end of the gas side connection pipe (51) opens to a portion near the upper end of the upper communication space (31a) in the first header collecting pipe (31).

液側接続管（52）は、比較的小径の配管で構成されている。液側接続管（52）の一端は、室外熱交換器（23）と膨張弁（24）を繋ぐ配管と接続されている。液側接続管（52）の他端は、第１ヘッダ集合管（31）における下側連通空間（31b）の下端寄りの部分に開口している。 The liquid side connection pipe (52) is constituted by a relatively small diameter pipe. One end of the liquid side connection pipe (52) is connected to a pipe connecting the outdoor heat exchanger (23) and the expansion valve (24). The other end of the liquid side connection pipe (52) opens to a portion near the lower end of the lower communication space (31b) in the first header collecting pipe (31).

室外熱交換器（23）は、凝縮器として機能する場合、ガス側接続管（51）から第１ヘッダ集合管（31）に流入した冷媒（ガス冷媒）が、主熱交換部（34）、補助熱交換部（35）の順に通過して凝縮するように構成されている。つまり、室外熱交換器（23）が凝縮器として機能する場合、第１ヘッダ集合管（31）の上側連通空間（31a）に流入した冷媒は、主熱交換部（34）の扁平管（33）を通過する間に凝縮して実質的に液単相状態となり、その後に補助熱交換部（35）の扁平管（33）へ流入してさらに冷却（過冷却）される。 When the outdoor heat exchanger (23) functions as a condenser, the refrigerant (gas refrigerant) flowing into the first header collecting pipe (31) from the gas side connection pipe (51) is converted into the main heat exchange section (34), It is configured to pass through the auxiliary heat exchange section (35) in order and condense. That is, when the outdoor heat exchanger (23) functions as a condenser, the refrigerant that has flowed into the upper communication space (31a) of the first header collecting pipe (31) flows into the flat pipe (33 ) Is condensed to substantially become a liquid single-phase state, and thereafter flows into the flat tube (33) of the auxiliary heat exchange section (35) to be further cooled (supercooled).

また、室外熱交換器（23）は、蒸発器として機能する場合、液側接続管（52）から第１ヘッダ集合管（31）の下側連通空間（31b）に流入した冷媒（液冷媒）が、補助熱交換部（35）、主熱交換部（34）の順に通過して蒸発するように構成されている。 When the outdoor heat exchanger (23) functions as an evaporator, the refrigerant (liquid refrigerant) that flows into the lower communication space (31b) of the first header collecting pipe (31) from the liquid side connection pipe (52) However, it is configured to pass through the auxiliary heat exchanging section (35) and the main heat exchanging section (34) in this order to evaporate.

このように、本実施形態の室外熱交換器（23）は、凝縮器として機能する場合も蒸発器として機能する場合も、冷媒が第２ヘッダ集合管（32）を介して主熱交換部（34）と補助熱交換部（35）の間を折り返して流れる箇所は１箇所である。 As described above, in the outdoor heat exchanger (23) of the present embodiment, the refrigerant passes through the second header collecting pipe (32), regardless of whether it functions as a condenser or an evaporator. 34) and the auxiliary heat exchanging part (35) fold back and flow at one place.

〈補助熱交換部の割合〉
本実施形態の室外熱交換器（23）は、複数の扁平管（33）の全体の伝熱面積に対する補助熱交換部（35）の扁平管（33）の伝熱面積の割合（以下、補助熱交割合Ｙともいう。）が所定の範囲に設定されている。ここで言う扁平管（33）の伝熱面積は、冷媒が流通する流体通路（33a）の表面積である。 <Proportion of auxiliary heat exchanger>
The outdoor heat exchanger (23) of this embodiment is a ratio of the heat transfer area of the flat tube (33) of the auxiliary heat exchange part (35) to the total heat transfer area of the plurality of flat tubes (33) (hereinafter referred to as auxiliary The heat exchange ratio Y is also set within a predetermined range. The heat transfer area of the flat tube (33) here is the surface area of the fluid passage (33a) through which the refrigerant flows.

補助熱交割合Ｙは、温度差ΔＴに対する過冷却度ＳＣの割合（過冷却度ＳＣ／温度差ΔＴ、以下、過冷却割合Ｘともいう。）に基づいて設定される。温度差ΔＴは、凝縮器として機能する室外熱交換器（23）において、冷媒の凝縮温度と熱交換前の空気の温度との温度差である。冷媒の凝縮温度は、室外熱交換器（27）における冷媒の凝縮飽和温度である。熱交換前の空気の温度は、室外熱交換器（23）へ流入する空気の温度である。冷媒の過冷却度ＳＣは、凝縮器として機能する室外熱交換器（23）において補助熱交換部（35）から第１ヘッダ集合管（31）へ流出した冷媒の過冷却度である。この過冷却度ＳＣは、上述した冷媒の凝縮温度（凝縮飽和温度）から室外熱交換器（23）から流出した冷媒（液冷媒）の温度を差し引いた値である。上述した冷媒の凝縮温度、熱交換前の空気の温度、過冷却度ＳＣは、室外熱交換器（23）を設計するに当たって予め設定される条件値である。 The auxiliary heat exchange ratio Y is set based on the ratio of the degree of supercooling SC to the temperature difference ΔT (supercooling degree SC / temperature difference ΔT, hereinafter also referred to as supercooling ratio X). The temperature difference ΔT is a temperature difference between the refrigerant condensation temperature and the air temperature before heat exchange in the outdoor heat exchanger (23) functioning as a condenser. The condensation temperature of the refrigerant is the condensation saturation temperature of the refrigerant in the outdoor heat exchanger (27). The temperature of the air before heat exchange is the temperature of the air flowing into the outdoor heat exchanger (23). The subcooling degree SC of the refrigerant is the degree of subcooling of the refrigerant that has flowed from the auxiliary heat exchanging section (35) to the first header collecting pipe (31) in the outdoor heat exchanger (23) functioning as a condenser. The degree of supercooling SC is a value obtained by subtracting the temperature of the refrigerant (liquid refrigerant) flowing out of the outdoor heat exchanger (23) from the above-described refrigerant condensation temperature (condensation saturation temperature). The above-described refrigerant condensing temperature, air temperature before heat exchange, and supercooling degree SC are condition values set in advance when designing the outdoor heat exchanger (23).

図４に示すように、補助熱交割合Ｙ（図４の縦軸）は、過冷却割合Ｘ（過冷却度ＳＣ／温度差ΔＴ、図４の横軸）が２０％〜８０％の範囲で、０％よりも高く且つ３５％以下に設定される。０％よりも高い値というのは、図４に示す●の曲線（温度差ΔＴ＝５℃の曲線）において過冷却割合Ｘ＝２０％から導かれ、３５％以下は、図４に示す□の曲線（温度差ΔＴ＝２０℃の曲線）において過冷却割合Ｘ＝８０％から導かれる。 As shown in FIG. 4, the auxiliary heat exchange ratio Y (vertical axis in FIG. 4) is within a range where the supercooling ratio X (supercooling degree SC / temperature difference ΔT, horizontal axis in FIG. 4) is 20% to 80%. , Higher than 0% and lower than 35%. The value higher than 0% is derived from the supercooling ratio X = 20% in the curve of ● shown in FIG. 4 (curve of temperature difference ΔT = 5 ° C.), and 35% or less is the value of □ shown in FIG. It is derived from the supercooling ratio X = 80% in the curve (curve with temperature difference ΔT = 20 ° C.).

ここで、上述した過冷却割合Ｘの範囲の下限値２０％および上限値８０％は、空気調和機（10）における冷媒回路（20）のＣＯＰ（成績係数）を考慮して一般に用いられる数値である。 Here, the lower limit 20% and the upper limit 80% of the range of the supercooling ratio X described above are generally used numerical values in consideration of the COP (coefficient of performance) of the refrigerant circuit (20) in the air conditioner (10). is there.

言い換えると、補助熱交割合Ｙは、室外熱交換器（23）が凝縮器として機能する場合、主熱交換部（34）および補助熱交換部（35）のうち補助熱交換部（35）のみに液冷媒が存在し且つその液冷媒で補助熱交換部（35）が概ね満たされた状態（図７（Ｄ）の状態）となるように、上述した所定の範囲に設定される。つまり、図７（Ｄ）は主熱交換部（34）には過冷却領域（液領域）は存在せず、補助熱交換部（35）の全体が過冷却領域（液領域）となる状態である。さらに、言い換えると、補助熱交割合Ｙは、室外熱交換器（23）が凝縮器として機能する際の凝縮能力と蒸発器として機能する際の蒸発能力とを十分に発揮させるように、上述した所定の範囲に設定される。 In other words, when the outdoor heat exchanger (23) functions as a condenser, the auxiliary heat exchange ratio Y is only the auxiliary heat exchange part (35) of the main heat exchange part (34) and the auxiliary heat exchange part (35). Is set to the predetermined range described above so that the auxiliary heat exchange section (35) is substantially filled with the liquid refrigerant (the state shown in FIG. 7D). That is, in FIG. 7D, the main heat exchange section (34) has no supercooling area (liquid area), and the auxiliary heat exchange section (35) as a whole becomes a supercooling area (liquid area). is there. Furthermore, in other words, the auxiliary heat exchange ratio Y is described above so that the outdoor heat exchanger (23) sufficiently exhibits the condensation ability when functioning as a condenser and the evaporation ability when functioning as an evaporator. A predetermined range is set.

より具体的に、補助熱交割合Ｙは、図４に示すように、過冷却割合Ｘを変数とする切片がゼロの二次関数で求められる。この二次関数は、室外熱交換器（23）が凝縮器として機能する場合、過冷却割合Ｘに応じて、室外熱交換器（23）が図７（Ｄ）に示す状態となる補助熱交割合Ｙの値がプロットされることで導出される。この二次関数は、図４に示すように、温度差ΔＴの値によって異なるものが用いられる。ここで、温度差ΔＴ＝１５℃，２０℃は主として夏期に行う定格運転の場合を示し、温度差ΔＴ＝５℃，１０℃は主として中間期に行う部分負荷運転の場合を示す。 More specifically, as shown in FIG. 4, the auxiliary heat exchange rate Y is obtained by a quadratic function having zero intercept with the subcooling rate X as a variable. This quadratic function indicates that when the outdoor heat exchanger (23) functions as a condenser, the auxiliary heat exchange in which the outdoor heat exchanger (23) is in the state shown in FIG. The value of the ratio Y is derived by plotting. As this quadratic function, a different one is used depending on the value of the temperature difference ΔT, as shown in FIG. Here, the temperature differences ΔT = 15 ° C. and 20 ° C. indicate the case of rated operation performed mainly in summer, and the temperature differences ΔT = 5 ° C. and 10 ° C. indicate the case of partial load operation performed mainly in the intermediate period.

図５は、過冷却割合Ｘ（過冷却度ＳＣ／温度差ΔＴ）＝５０％で固定した条件下で、補助熱交割合Ｙ（横軸）と凝縮能力（縦軸）の関係を示す。凝縮能力は、凝縮器として機能する室外熱交換器（23）において冷媒と空気の熱交換量である。図５によれば、温度差ΔＴに関係なく、補助熱交割合Ｙが低すぎても高すぎても凝縮能力が低下することが分かる。つまり、室外熱交換器（23）では、凝縮能力が最高となる最適な補助熱交割合Ｙが存在する。 FIG. 5 shows the relationship between the auxiliary heat exchange ratio Y (horizontal axis) and the condensing capacity (vertical axis) under the condition that the supercooling ratio X (supercooling degree SC / temperature difference ΔT) is fixed at 50%. The condensation capacity is the amount of heat exchange between the refrigerant and air in the outdoor heat exchanger (23) that functions as a condenser. According to FIG. 5, it can be seen that regardless of the temperature difference ΔT, the condensing capacity decreases if the auxiliary heat exchange ratio Y is too low or too high. That is, in the outdoor heat exchanger (23), there is an optimum auxiliary heat exchange rate Y that maximizes the condensation capacity.

具体的に、凝縮器として機能する室外熱交換器（23）において、補助熱交割合Ｙが高くなると、全体における主熱交換部（34）の割合が低くなるため、冷媒が空気と熱交換して凝縮する領域が減少し凝縮能力が低下する。一方、室外熱交換器（23）が蒸発器として機能する場合について考えると、補助熱交割合Ｙが高くなって主熱交換部（34）の割合が低くなると、冷媒が空気と熱交換して蒸発する領域が減少するため、蒸発能力が低下する。つまり、主熱交換部（34）は冷媒と空気の温度差を大きくとれる部分であるため、主熱交換部（34）の割合が減少すると、凝縮能力および蒸発能力の何れもが低下してしまう。 Specifically, in the outdoor heat exchanger (23) functioning as a condenser, when the auxiliary heat exchange ratio Y increases, the ratio of the main heat exchange section (34) in the whole decreases, so that the refrigerant exchanges heat with air. As a result, the condensation area decreases and the condensation capacity decreases. On the other hand, considering the case where the outdoor heat exchanger (23) functions as an evaporator, when the auxiliary heat exchange ratio Y increases and the ratio of the main heat exchange section (34) decreases, the refrigerant exchanges heat with air. Since the area to evaporate decreases, the evaporation capability decreases. That is, since the main heat exchanging portion (34) is a portion where the temperature difference between the refrigerant and the air can be greatly increased, if the ratio of the main heat exchanging portion (34) is decreased, both the condensing capacity and the evaporating capacity are decreased. .

また、凝縮器として機能する室外熱交換器（23）において、補助熱交割合Ｙが低くなると、全体における主熱交換部（34）の割合は高くなるが、過冷却領域（液領域）が主熱交換部（34）の一部にまで及んでしまう。つまり、補助熱交割合Ｙが低くなると、図７の（Ｅ）〜（Ｇ）に示すように、補助熱交換部（35）の領域だけでなく、主熱交換部（34）における補助熱交換部（35）の直近の領域が過冷却領域（液領域）となる。そうすると、主熱交換部（34）では液冷媒の存在によって冷媒の偏流が生じてしまう。これによって、第２ヘッダ集合管（32）において主熱交換部（34）に対応する部分に液冷媒が溜まってしまい、冷媒流れが阻害される。その結果、室外熱交換器（23）における冷媒循環量が減少し、凝縮能力が低下してしまう。一方、室外熱交換器（23）が蒸発器として機能する場合について考えると、補助熱交割合Ｙが低くなって主熱交換部（34）の割合が高くなると、冷媒が空気と熱交換して蒸発する領域が増大するため、蒸発能力が高くなる。 In addition, in the outdoor heat exchanger (23) functioning as a condenser, when the auxiliary heat exchange ratio Y decreases, the ratio of the main heat exchange section (34) increases, but the supercooling area (liquid area) is mainly used. It reaches even a part of the heat exchange section (34). That is, when the auxiliary heat exchange ratio Y is low, as shown in FIGS. 7E to 7G, the auxiliary heat exchange is performed not only in the area of the auxiliary heat exchange section (35) but also in the main heat exchange section (34). The area immediately adjacent to the part (35) becomes the supercooling area (liquid area). Then, in the main heat exchanging part (34), the refrigerant drifts due to the presence of the liquid refrigerant. As a result, the liquid refrigerant accumulates in the portion corresponding to the main heat exchange section (34) in the second header collecting pipe (32), and the refrigerant flow is obstructed. As a result, the amount of refrigerant circulating in the outdoor heat exchanger (23) decreases, and the condensing capacity decreases. On the other hand, considering the case where the outdoor heat exchanger (23) functions as an evaporator, when the auxiliary heat exchange ratio Y decreases and the ratio of the main heat exchanger (34) increases, the refrigerant exchanges heat with air. Since the area to evaporate increases, the evaporation capability increases.

このように、室外熱交換器（23）において、補助熱交割合Ｙが低くなりすぎると、蒸発能力は高くなるが、上述したように液冷媒が主熱交換部（34）にまであふれてしまうため凝縮能力は著しく低下する。また、室外熱交換器（23）において、補助熱交割合Ｙが高くなりすぎると、凝縮能力および蒸発能力は低下する。このことから、凝縮能力が最高となる最適な補助熱交割合Ｙ（図５に示す各曲線のピーク点）が存在することが分かる。そして、この最適な補助熱交割合Ｙを採ることで、凝縮能力を最高としつつ、できるだけ高い蒸発能力を稼ぐことができる。 As described above, in the outdoor heat exchanger (23), if the auxiliary heat exchange ratio Y is too low, the evaporation capacity increases, but the liquid refrigerant overflows to the main heat exchange section (34) as described above. Therefore, the condensation capacity is significantly reduced. Further, in the outdoor heat exchanger (23), when the auxiliary heat exchange ratio Y becomes too high, the condensation capacity and the evaporation capacity are lowered. From this, it can be seen that there is an optimum auxiliary heat exchange ratio Y (the peak point of each curve shown in FIG. 5) at which the condensing capacity is maximized. And by taking this optimal auxiliary | assistant heat exchange ratio Y, it can earn as high a vaporization capability as possible, making the condensation capability the highest.

また、図５によれば、温度差ΔＴが高くなるほど、凝縮能力が最高となる補助熱交割合Ｙの値は高くなることも分かる。 Further, according to FIG. 5, it can be seen that the value of the auxiliary heat exchange ratio Y at which the condensing capacity is maximized increases as the temperature difference ΔT increases.

図６は、温度差ΔＴを固定した条件下で、過冷却度ＳＣ（横軸）と凝縮能力（縦軸）の関係を示す。図６によれば、過冷却度ＳＣが高くなると、即ち過冷却割合Ｘ（過冷却度ＳＣ／温度差ΔＴ）が高くなると、凝縮能力が少しずつ低下していくが、過冷却割合Ｘが所定値になると急激に凝縮能力が低下することが分かる。 FIG. 6 shows the relationship between the degree of supercooling SC (horizontal axis) and the condensing capacity (vertical axis) under the condition that the temperature difference ΔT is fixed. According to FIG. 6, when the degree of supercooling SC increases, that is, when the supercooling ratio X (supercooling degree SC / temperature difference ΔT) increases, the condensing capacity gradually decreases, but the supercooling ratio X is predetermined. It can be seen that the condensing capacity suddenly decreases when the value is reached.

具体的に、過冷却度ＳＣ（過冷却割合Ｘ）が比較的低く、凝縮能力が１００％発揮されている場合（図６に示す「Ａ」）、室外熱交換器（23）は図７（Ａ）に示す状態となる。つまり、室外熱交換器（23）において、補助熱交換部（35）の一部が過冷却領域（液領域）となり、それ以外の主熱交換部（34）の全体と補助熱交換部（35）の残りの部分が凝縮領域（ガス領域）となる。そして、過冷却度ＳＣが高くなると（図６に示す「Ｂ」、「Ｃ」）、室外熱交換器（23）は図７（Ｂ）および（Ｃ）に示す状態となる。つまり、過冷却度ＳＣが高くなると、補助熱交換部（35）における過冷却領域（液領域）が増大する。このように、過冷却領域（液領域）が増大すると、その増大した分だけ凝縮領域（ガス領域）が減少するため、凝縮能力が低下する。図７（Ａ）〜（Ｃ）に示す状態は、補助熱交換部（35）の領域が無駄に設けられていることとなる。 Specifically, when the degree of supercooling SC (supercooling ratio X) is relatively low and the condensing capacity is 100% ("A" shown in FIG. 6), the outdoor heat exchanger (23) is shown in FIG. The state shown in A) is obtained. That is, in the outdoor heat exchanger (23), a part of the auxiliary heat exchange part (35) becomes a supercooling area (liquid area), and the other main heat exchange part (34) and the auxiliary heat exchange part (35) The remaining part of) becomes a condensation region (gas region). When the degree of supercooling SC becomes high (“B” and “C” shown in FIG. 6), the outdoor heat exchanger (23) is in the state shown in FIGS. 7B and 7C. That is, when the degree of supercooling SC increases, the supercooling region (liquid region) in the auxiliary heat exchange section (35) increases. As described above, when the supercooling region (liquid region) increases, the condensation region (gas region) decreases by the increased amount, and the condensing capacity decreases. In the state shown in FIGS. 7A to 7C, the auxiliary heat exchange section (35) is provided in vain.

さらに、過冷却度ＳＣが高くなると（図６に示す「Ｄ」）、室外熱交換器（23）は図７（Ｄ）に示す状態となる。この状態は、上述したように、主熱交換部（34）の全体が凝縮領域（ガス領域）となり、補助熱交換部（35）の全体が過冷却領域（液領域）となる。図７の（Ａ）から（Ｄ）までは、補助熱交換部（35）において過冷却領域（液領域）が増大し、その増大した分だけ凝縮領域（ガス領域）が減少するので、凝縮能力が少しずつ低下する。 Further, when the degree of supercooling SC becomes high (“D” shown in FIG. 6), the outdoor heat exchanger (23) is in the state shown in FIG. 7D. In this state, as described above, the entire main heat exchanging section (34) becomes a condensation area (gas area), and the entire auxiliary heat exchanging section (35) becomes a supercooling area (liquid area). From (A) to (D) of FIG. 7, the subcooling region (liquid region) increases in the auxiliary heat exchanger (35), and the condensation region (gas region) decreases by the increased amount. Gradually decreases.

さらに、図６において、過冷却度ＳＣが高くなると、温度差ΔＴ＝７℃の場合は「Ｄ」から「Ｆ」へ、温度差ΔＴ＝１４℃の場合は「Ｄ」から「Ｅ」へ凝縮能力が急激に低下する。この図６の「Ｅ」および「Ｆ」の場合、室外熱交換器（23）は図７（Ｅ）および（Ｆ）に示す状態となる。この状態は、上述したように、補助熱交換部（35）の全体と主熱交換部（34）の一部が過冷却領域（液領域）となり、主熱交換部（34）の残りの部分が凝縮領域（ガス領域）となる。この状態では、凝縮領域（ガス領域）が減少しただけではなく、上述したように主熱交換部（34）において冷媒の偏流が生じるため、凝縮能力が著しく低下する。 Further, in FIG. 6, when the degree of supercooling SC is increased, the temperature difference ΔT = 7 ° C. is condensed from “D” to “F”, and the temperature difference ΔT = 14 ° C. is condensed from “D” to “E”. Ability drops rapidly. In the case of “E” and “F” in FIG. 6, the outdoor heat exchanger (23) is in the state shown in FIGS. 7 (E) and (F). In this state, as described above, the entire auxiliary heat exchanging part (35) and a part of the main heat exchanging part (34) become a supercooling area (liquid area), and the remaining part of the main heat exchanging part (34). Becomes a condensation region (gas region). In this state, not only the condensing region (gas region) is reduced, but also the refrigerant drifts in the main heat exchanging portion (34) as described above, so the condensing capacity is significantly reduced.

そして、温度差ΔＴ＝１４℃の場合、さらに過冷却度ＳＣが高くなると（図６に示す「Ｆ」、「Ｇ」）、室外熱交換器（23）は図７（Ｆ）および（Ｇ）に示す状態となる。この状態では、主熱交換部（34）における過冷却領域（液領域）がさらに増大し凝縮領域（ガス領域）が減少するため、凝縮能力がさらに低下する。 When the temperature difference ΔT = 14 ° C. and the supercooling degree SC is further increased (“F” and “G” shown in FIG. 6), the outdoor heat exchanger (23) is shown in FIGS. 7 (F) and (G). It will be in the state shown in In this state, the supercooling region (liquid region) in the main heat exchange section (34) further increases and the condensing region (gas region) decreases, so that the condensing capacity further decreases.

以上より、図７（Ａ）〜（Ｃ）に示す状態は、補助熱交換部（35）の領域が無駄に設けられているため、主熱交換部（34）の領域が必要以上に少なくなっている。そうすると、蒸発能力が無駄に削減されることとなるので、補助熱交換部（35）の領域（補助熱交割合Ｙ）を必要以上にとることは蒸発能力を無駄に低下させる結果となる。そこで、単に補助熱交換部（35）の領域（補助熱交割合Ｙ）を減少させると、図７（Ｅ）〜（Ｇ）に示す状態のように、補助熱交換部（35）の領域が不足して過冷却領域（液領域）が主熱交換部（34）にまで及んでしまう。そうなると、上述したように凝縮能力が著しく低下する。つまり、この場合、蒸発能力は高くなるものの、凝縮能力を著しく低下させることとなる。このことから、室外熱交換器（23）が凝縮器として機能する場合は、図７（Ｄ）に示す状態のように、主熱交換部（34）の全体がガス領域となり補助熱交換部（35）の全体が過冷却領域（液領域）となるのが最適となる。つまり、室外熱交換器（23）が凝縮器として機能する場合は図７（Ｄ）に示す状態となるように、補助熱交割合Ｙを設定することで、凝縮能力および蒸発能力を最適に発揮させることができる。なお、図６に示す「Ａ」〜「Ｇ」は、それぞれ図７の（Ａ）〜（Ｇ）に対応している。 From the above, in the states shown in FIGS. 7A to 7C, the area of the auxiliary heat exchange section (35) is provided unnecessarily, so the area of the main heat exchange section (34) is unnecessarily small. ing. As a result, the evaporation capacity is unnecessarily reduced. Therefore, taking the area (auxiliary heat exchange ratio Y) of the auxiliary heat exchanging section (35) more than necessary results in an unnecessary decrease in the evaporation capacity. Therefore, if the area (auxiliary heat exchange ratio Y) of the auxiliary heat exchange section (35) is simply decreased, the area of the auxiliary heat exchange section (35) becomes as shown in FIGS. 7 (E) to (G). Insufficiently, the supercooling region (liquid region) reaches the main heat exchange section (34). Then, as described above, the condensation capacity is significantly reduced. That is, in this case, although the evaporation capability is increased, the condensation capability is remarkably reduced. From this, when the outdoor heat exchanger (23) functions as a condenser, as shown in FIG. 7D, the entire main heat exchange part (34) becomes a gas region, and the auxiliary heat exchange part ( It is optimal that the whole of 35) becomes the supercooling region (liquid region). In other words, when the outdoor heat exchanger (23) functions as a condenser, the auxiliary heat exchange rate Y is set so that the state shown in FIG. Can be made. Note that “A” to “G” illustrated in FIG. 6 correspond to (A) to (G) in FIG. 7, respectively.

以上の観点から、過冷却割合Ｘが２０％〜８０％の範囲において、過冷却割合Ｘに応じて室外熱交換器（23）が図７（Ｄ）に示す状態となる補助熱交割合Ｙ（０％よりも高く且つ３５％以下）を導出したのが図４に示す各曲線（二次曲線）となる。 From the above viewpoint, in the range where the supercooling ratio X is 20% to 80%, the auxiliary heat exchange ratio Y () in which the outdoor heat exchanger (23) is in the state shown in FIG. Each curve (second-order curve) shown in FIG. 4 is derived from higher than 0% and 35% or less.

また、本実施形態の室外熱交換器（23）は、複数の扁平管（33）が互いに同一の伝熱面積を有する場合、補助熱交割合Ｙは本数で規定してもよい。つまり、室外熱交換器（23）において、複数の扁平管（33）の全体本数に対する補助熱交換部（35）の扁平管（33）の本数の割合が、０％よりも高く且つ３５％以下に設定される。 In the outdoor heat exchanger (23) of the present embodiment, the auxiliary heat exchange ratio Y may be defined by the number when the plurality of flat tubes (33) have the same heat transfer area. That is, in the outdoor heat exchanger (23), the ratio of the number of flat tubes (33) of the auxiliary heat exchange section (35) to the total number of flat tubes (33) is higher than 0% and not more than 35%. Set to

−実施形態の効果−
本実施形態の室外熱交換器（23）は、過冷却割合Ｘ（過冷却度ＳＣ／温度差ΔＴ）が２０％〜８０％の設計条件において、複数の扁平管（33）の全体の伝熱面積に対する上記補助熱交換部（35）の扁平管（33）の伝熱面積の割合が、０％よりも高く且つ３５％以下に設定される。また、本実施形態の室外熱交換器（23）は、過冷却割合Ｘ（過冷却度ＳＣ／温度差ΔＴ）が２０％〜８０％の設計条件において、複数の扁平管（33）の全体本数に対する補助熱交換部（35）の扁平管（33）の本数の割合が、０％よりも高く且つ３５％以下に設定される。 -Effect of the embodiment-
In the outdoor heat exchanger (23) of the present embodiment, the overall heat transfer of the plurality of flat tubes (33) under the design condition where the supercooling ratio X (supercooling degree SC / temperature difference ΔT) is 20% to 80%. The ratio of the heat transfer area of the flat tube (33) of the auxiliary heat exchange section (35) to the area is set to be higher than 0% and 35% or less. Further, the outdoor heat exchanger (23) of the present embodiment has the total number of flat tubes (33) under the design condition where the supercooling ratio X (supercooling degree SC / temperature difference ΔT) is 20% to 80%. The ratio of the number of the flat tubes (33) of the auxiliary heat exchange section (35) to is set to be higher than 0% and 35% or less.

そのため、室外熱交換器（23）が凝縮器として機能する場合、図７（Ｄ）に示す状態のように、主熱交換部（34）の全体がガス領域（凝縮領域）となり、補助熱交換部（35）の全体が液領域（過冷却領域）となる。これによって、必要な過冷却度ＳＣを保持して最高の凝縮能力を発揮させる一方、できるだけ高い蒸発能力を確保し得る室外熱交換器（23）を提供することができる。つまり、凝縮能力および蒸発能力の両方を最適化し得る室外熱交換器（23）を提供できる。 Therefore, when the outdoor heat exchanger (23) functions as a condenser, as shown in FIG. 7 (D), the entire main heat exchange part (34) becomes a gas region (condensation region), and auxiliary heat exchange is performed. The entire part (35) becomes a liquid region (supercooling region). As a result, it is possible to provide an outdoor heat exchanger (23) that can maintain the necessary supercooling degree SC and exhibit the highest condensing capacity while ensuring as high an evaporation capacity as possible. That is, an outdoor heat exchanger (23) that can optimize both the condensation capacity and the evaporation capacity can be provided.

これによって、冷房能力および暖房能力の両方を十分に稼げる空気調和機（10）を提供することができる。 Thus, it is possible to provide the air conditioner (10) that can sufficiently obtain both the cooling capacity and the heating capacity.

−実施形態の変形例−
本変形例は、図８および図９に示すように、上記実施形態の室外熱交換器（23）の構成を変更したものである。ここでは、上記実施形態の室外熱交換器（23）と異なる部分について説明する。 -Modification of the embodiment-
In this modification, as shown in FIGS. 8 and 9, the configuration of the outdoor heat exchanger (23) of the above embodiment is changed. Here, a different part from the outdoor heat exchanger (23) of the said embodiment is demonstrated.

図８に示すように、本変形例の室外熱交換器（23）において、主熱交換部（34）および補助熱交換部（35）は、それぞれ上下に三つずつの熱交換領域（34a〜34c,35a〜35c）に区分されている。具体的に、主熱交換部（34）には、下から上に向かって順に、第１主熱交換領域（34a）と、第２主熱交換領域（34b）と、第３主熱交換領域（34c）とが形成されている。補助熱交換部（35）には、下から上に向かって順に、第１補助熱交換領域（35a）と、第２補助熱交換領域（35b）と、第３補助熱交換領域（35c）とが形成されている。このように、本変形例の主熱交換部（34）および補助熱交換部（35）では、扁平管（33）の配列方向（上下方向）に、互いに複数且つ同数の熱交換領域（34a〜34c,35a〜35c）に区分されている。なお、各熱交換部（34,35）に形成される熱交換領域（34a〜34c,35a〜35c）の数は、二つであってもよいし、四つ以上であってもよい。 As shown in FIG. 8, in the outdoor heat exchanger (23) of the present modification, the main heat exchange part (34) and the auxiliary heat exchange part (35) each have three heat exchange regions (34a to 34a 34c, 35a to 35c). Specifically, the main heat exchange section (34) includes a first main heat exchange region (34a), a second main heat exchange region (34b), and a third main heat exchange region in order from bottom to top. (34c) is formed. The auxiliary heat exchange section (35) includes, in order from the bottom to the top, a first auxiliary heat exchange region (35a), a second auxiliary heat exchange region (35b), and a third auxiliary heat exchange region (35c). Is formed. Thus, in the main heat exchange part (34) and the auxiliary heat exchange part (35) of the present modification, a plurality of and the same number of heat exchange regions (34a to 34a) are arranged in the arrangement direction (vertical direction) of the flat tubes (33). 34c, 35a to 35c). The number of heat exchange regions (34a to 34c, 35a to 35c) formed in each heat exchange part (34, 35) may be two, or may be four or more.

また、補助熱交換部（35）では、各補助熱交換領域（35a〜35c）の扁平管（33）の本数が互いに同一（本変形例では、三本ずつ）となっている。つまり、本変形例の補助熱交換部（35）では、各補助熱交換領域（35a〜35c）の扁平管（33）の総流路断面積（即ち、各補助熱交換領域（35a〜35c）における流体通路（33a）の通路断面積の合計）が互いに同一となっている。なお、本変形例に係る各扁平管（33）も、上記実施形態と同様、互いに同一の流路断面積を有している。 Further, in the auxiliary heat exchange section (35), the number of flat tubes (33) in each auxiliary heat exchange region (35a to 35c) is the same (three in this modification). That is, in the auxiliary heat exchange part (35) of this modification, the total flow path cross-sectional area of the flat tubes (33) of each auxiliary heat exchange region (35a to 35c) (that is, each auxiliary heat exchange region (35a to 35c)) The sum of the passage sectional areas of the fluid passages (33a) is the same. In addition, each flat tube (33) which concerns on this modification also has the mutually same flow-path cross-sectional area similarly to the said embodiment.

第１ヘッダ集合管（31）および第２ヘッダ集合管（32）の内部空間は、複数の仕切板（39）によって上下に仕切られている。 The internal space of the first header collecting pipe (31) and the second header collecting pipe (32) is partitioned up and down by a plurality of partition plates (39).

具体的に、第１ヘッダ集合管（31）の内部空間は、主熱交換部（34）に対応したガス冷媒の主連通空間（61）と、補助熱交換部（35）に対応した液冷媒の補助連通空間（62）とに仕切られている。なお、ここで言う液冷媒とは、液単相状態の冷媒または気液二相状態の冷媒を意味する。主連通空間（61）は、全ての主熱交換領域（34a〜34c）に共通に対応した単一の空間である。つまり、主連通空間（61）は、全ての主熱交換領域（34a〜34c）の扁平管（33）と連通している。補助連通空間（62）は、更に仕切板（39）によって、各補助熱交換領域（35a〜35c）に対応した該補助熱交換領域（35a〜35c）と同数（三つ）の連通空間（62a〜62c）に上下に仕切られている。つまり、補助連通空間（62）では、第１補助熱交換領域（35a）の扁平管（33）と連通する第１連通空間（62a）と、第２補助熱交換領域（35b）の扁平管（33）と連通する第２連通空間（62b）と、第３補助熱交換領域（35c）の扁平管（33）と連通する第３連通空間（62c）とが形成されている。 Specifically, the internal space of the first header collecting pipe (31) includes a gas refrigerant main communication space (61) corresponding to the main heat exchange section (34) and a liquid refrigerant corresponding to the auxiliary heat exchange section (35). The auxiliary communication space (62). The liquid refrigerant referred to here means a liquid single-phase refrigerant or a gas-liquid two-phase refrigerant. The main communication space (61) is a single space corresponding to all the main heat exchange regions (34a to 34c) in common. That is, the main communication space (61) communicates with the flat tubes (33) of all the main heat exchange regions (34a to 34c). The auxiliary communication space (62) is further divided by the partition plate (39) into the same number (three) of communication spaces (62a) as the auxiliary heat exchange regions (35a to 35c) corresponding to the auxiliary heat exchange regions (35a to 35c). To 62c). That is, in the auxiliary communication space (62), the first communication space (62a) communicating with the flat tube (33) in the first auxiliary heat exchange region (35a) and the flat tube ( A second communication space (62b) communicating with 33) and a third communication space (62c) communicating with the flat tube (33) of the third auxiliary heat exchange region (35c) are formed.

第２ヘッダ集合管（32）の内部空間は、上下に五つの連通空間（71a〜71e）に仕切られている。具体的に、第２ヘッダ集合管（32）の内部空間は、主熱交換部（34）において最下に位置する第１主熱交換領域（34a）と補助熱交換部（35）において最上に位置する第３補助熱交換領域（35c）を除く各主熱交換領域（34b,34c）および各補助熱交換領域（35a,35b）に対応した四つの連通空間（71a,71b,71d,71e）と、第１主熱交換領域（34a）および第３補助熱交換領域（35c）に共通に対応した単一の連通空間（71c）とに仕切られている。つまり、第２ヘッダ集合管（32）の内部空間では、第１補助熱交換領域（35a）の扁平管（33）と連通する第１連通空間（71a）と、第２補助熱交換領域（35b）の扁平管（33）と連通する第２連通空間（71b）と、第３補助熱交換領域（35c）および第１主熱交換領域（34a）の双方の扁平管（33）と連通する第３連通空間（71c）と、第２主熱交換領域（34b）の扁平管（33）と連通する第４連通空間（71d）と、第３主熱交換領域（34c）の扁平管（33）と連通する第５連通空間（71e）とが形成されている。第１主熱交換領域（34a）と第３補助熱交換領域（35c）は、両熱交換部（34,35）において互いに隣り合う熱交換領域である。 The internal space of the second header collecting pipe (32) is partitioned into five communication spaces (71a to 71e) vertically. Specifically, the internal space of the second header collecting pipe (32) is located at the uppermost position in the first main heat exchange region (34a) and the auxiliary heat exchange section (35) located at the lowermost position in the main heat exchange section (34). Four communication spaces (71a, 71b, 71d, 71e) corresponding to each main heat exchange region (34b, 34c) and each auxiliary heat exchange region (35a, 35b) excluding the third auxiliary heat exchange region (35c) located And a single communication space (71c) corresponding to the first main heat exchange region (34a) and the third auxiliary heat exchange region (35c) in common. That is, in the internal space of the second header collecting pipe (32), the first communication space (71a) communicating with the flat pipe (33) of the first auxiliary heat exchange area (35a) and the second auxiliary heat exchange area (35b). ) Communicated with the second communication space (71b) communicating with the flat tube (33) and the flat tubes (33) of both the third auxiliary heat exchange region (35c) and the first main heat exchange region (34a). Three communication spaces (71c), a fourth communication space (71d) communicating with the flat tube (33) in the second main heat exchange region (34b), and a flat tube (33) in the third main heat exchange region (34c) A fifth communication space (71e) that communicates with the first communication space is formed. The first main heat exchange region (34a) and the third auxiliary heat exchange region (35c) are heat exchange regions adjacent to each other in both heat exchange portions (34, 35).

第２ヘッダ集合管（32）では、第４連通空間（71d）および第５連通空間（71e）と、第１連通空間（71a）および第２連通空間（71b）とが、各一で対となっている。具体的に、第１連通空間（71a）と第５連通空間（71e）が対となり、第２連通空間（71b）と第４連通空間（71d）が対となっている。そして、第２ヘッダ集合管（32）には、第２連通空間（71b）と第４連通空間（71d）とを接続する第１連通管（72）と、第１連通空間（71a）と第５連通空間（71e）とを接続する第２連通管（73）とが設けられている。つまり、本変形例の室外熱交換器（23）では、第１主熱交換領域（34a）と第３補助熱交換領域（35c）が対となり、第２主熱交換領域（34b）と第２補助熱交換領域（35b）が対となり、第３主熱交換領域（34c）と第１補助熱交換領域（35a）が対となっている。 In the second header collecting pipe (32), the fourth communication space (71d) and the fifth communication space (71e), and the first communication space (71a) and the second communication space (71b) are in pairs. It has become. Specifically, the first communication space (71a) and the fifth communication space (71e) are paired, and the second communication space (71b) and the fourth communication space (71d) are paired. The second header collecting pipe (32) includes a first communication pipe (72) connecting the second communication space (71b) and the fourth communication space (71d), a first communication space (71a), and a second communication space. A second communication pipe (73) that connects the five communication spaces (71e) is provided. That is, in the outdoor heat exchanger (23) of this modification, the first main heat exchange region (34a) and the third auxiliary heat exchange region (35c) are paired, and the second main heat exchange region (34b) and the second The auxiliary heat exchange region (35b) is paired, and the third main heat exchange region (34c) and the first auxiliary heat exchange region (35a) are paired.

そして、図９に示すように、室外熱交換器（23）では、第２ヘッダ集合管（32）における上側二つの仕切板（39）のそれぞれの側方に位置する部分が、主熱交換領域（34a〜34c）同士の境界部（53）となっている。また、室外熱交換器（23）では、第１ヘッダ集合管（31）における下側二つの仕切板（39）と第２ヘッダ集合管（32）における下側二つの仕切板（39）との間の部分が、補助熱交換領域（35a〜35c）同士の境界部（54）となっている。また、室外熱交換器（23）では、第１ヘッダ集合管（31）における最上の仕切板（39）の側方に位置する部分が、第１主熱交換領域（34a）と第３補助熱交換領域（35c）の境界部（55）、即ち主熱交換部（34）の主熱交換領域（34a）と補助熱交換部（35）の補助熱交換領域（35c）の境界部（55）となっている。 And in the outdoor heat exchanger (23), as shown in FIG. 9, the part located in each side of the upper two partition plates (39) in the second header collecting pipe (32) is the main heat exchange region. It is the boundary part (53) between (34a-34c). In the outdoor heat exchanger (23), the lower two partition plates (39) in the first header collecting pipe (31) and the lower two partition plates (39) in the second header collecting pipe (32) The part in between is the boundary part (54) between the auxiliary heat exchange regions (35a to 35c). In the outdoor heat exchanger (23), a portion of the first header collecting pipe (31) located on the side of the uppermost partition plate (39) is the first main heat exchange region (34a) and the third auxiliary heat. The boundary part (55) of the exchange region (35c), that is, the boundary part (55) between the main heat exchange region (34a) of the main heat exchange part (34) and the auxiliary heat exchange region (35c) of the auxiliary heat exchange part (35). It has become.

図８に示すように、第１ヘッダ集合管（31）には、ガス側接続管（51）と液側接続管（52）とが設けられている。液側接続管（52）は、一つの分流器（52d）と、三本の細径管（52a〜52c）とを備えている。分流器（52d）の下端部には、室外熱交換器（23）と膨張弁（24）を繋ぐ配管が接続されている。分流器（52d）の上端部には、各細径管（52a〜52c）の一端が接続されている。分流器（52d）の内部では、その下端部に接続された配管と、各細径管（52a〜52c）とが連通している。各細径管（52a〜52c）の他端は、第１ヘッダ集合管（31）の補助連通空間（62）に接続され、対応する連通空間（62a〜62c）に連通している。 As shown in FIG. 8, the first header collecting pipe (31) is provided with a gas side connecting pipe (51) and a liquid side connecting pipe (52). The liquid side connection pipe (52) includes one shunt (52d) and three small diameter pipes (52a to 52c). A pipe connecting the outdoor heat exchanger (23) and the expansion valve (24) is connected to the lower end of the flow divider (52d). One end of each small-diameter pipe (52a to 52c) is connected to the upper end of the flow divider (52d). Inside the flow divider (52d), the pipe connected to the lower end portion thereof communicates with the small diameter pipes (52a to 52c). The other end of each small-diameter pipe (52a to 52c) is connected to the auxiliary communication space (62) of the first header collecting pipe (31) and communicates with the corresponding communication space (62a to 62c).

図９にも示すように、各細径管（52a〜52c）は、対応する連通空間（62a〜62c）の下端寄りの部分に開口している。つまり、第１細径管（52a）は第１連通空間（62a）の下端寄りの部分に開口し、第２細径管（52b）は第２連通空間（62b）の下端寄りの部分に開口し、第３細径管（52c）は第３連通空間（62c）の下端寄りの部分に開口している。なお、各細径管（52a〜52c）の長さは、各補助熱交換領域（35a〜35c）へ流入する冷媒の流量の差がなるべく小さくなるように、個別に設定されている。 As shown also in FIG. 9, each small diameter pipe (52a-52c) is opened in the part near the lower end of corresponding communication space (62a-62c). That is, the first small diameter pipe (52a) opens at a portion near the lower end of the first communication space (62a), and the second small diameter pipe (52b) opens at a portion near the lower end of the second communication space (62b). The third small-diameter pipe (52c) opens at a portion near the lower end of the third communication space (62c). In addition, the length of each small diameter pipe | tube (52a-52c) is set individually so that the difference in the flow volume of the refrigerant | coolant which flows into each auxiliary heat exchange area | region (35a-35c) may become as small as possible.

ガス側接続管（51）は、上記実施形態と同様、比較的大径の一つの配管で構成されている。ガス側接続管（51）の一端は、室外熱交換器（23）と四方切換弁（22）の第３のポートを繋ぐ配管と接続されている。ガス側接続管（51）の他端は、第１ヘッダ集合管（31）における主連通空間（61）の上端寄りの部分に開口している。 The gas side connecting pipe (51) is configured by one pipe having a relatively large diameter, as in the above embodiment. One end of the gas side connection pipe (51) is connected to a pipe connecting the outdoor heat exchanger (23) and the third port of the four-way switching valve (22). The other end of the gas side connection pipe (51) opens to a portion near the upper end of the main communication space (61) in the first header collecting pipe (31).

本変形例の室外熱交換器（23）は、凝縮器として機能する場合、ガス側接続管（51）から第１ヘッダ集合管（31）に流入した冷媒（ガス冷媒）が、主熱交換部（34）の各主熱交換領域（34a〜34c）、補助熱交換部（35）の各補助熱交換領域（35a〜35c）の順に通過して凝縮するように構成されている。つまり、室外熱交換器（23）が凝縮器として機能する場合、第１ヘッダ集合管（31）の主連通空間（61）に流入した冷媒は、各主熱交換領域（34a〜34c）の扁平管（33）を通過する間に凝縮して実質的に液単相状態となる。その後、第４連通空間（71d）および第５連通空間（71e）の冷媒は、連通管（72,73）、第１連通空間（71a）および第２連通空間（71b）を介して第１補助熱交換領域（35a）および第２補助熱交換領域（35b）へ流入する。一方、第１主熱交換領域（34a）を通過した冷媒は、第３連通空間（71c）を介して第３補助熱交換領域（35c）へ流入する。そして、各補助熱交換領域（35a〜35c）の扁平管（33）では冷媒がさらに冷却（過冷却）されて、補助連通空間（62）から液側接続管（52）を介して冷媒回路（20）へ流出する。 When the outdoor heat exchanger (23) of the present modification functions as a condenser, the refrigerant (gas refrigerant) flowing into the first header collecting pipe (31) from the gas side connection pipe (51) is used as the main heat exchange section. Each main heat exchange area (34a to 34c) of (34) and each auxiliary heat exchange area (35a to 35c) of the auxiliary heat exchange section (35) are passed through in this order to condense. That is, when the outdoor heat exchanger (23) functions as a condenser, the refrigerant flowing into the main communication space (61) of the first header collecting pipe (31) is flattened in each main heat exchange region (34a to 34c). While passing through the pipe (33), it condenses into a substantially liquid single phase state. Thereafter, the refrigerant in the fourth communication space (71d) and the fifth communication space (71e) is first auxiliary via the communication pipe (72, 73), the first communication space (71a), and the second communication space (71b). It flows into the heat exchange area (35a) and the second auxiliary heat exchange area (35b). On the other hand, the refrigerant that has passed through the first main heat exchange region (34a) flows into the third auxiliary heat exchange region (35c) through the third communication space (71c). Then, the refrigerant is further cooled (supercooled) in the flat tubes (33) of each auxiliary heat exchange region (35a to 35c), and the refrigerant circuit (from the auxiliary communication space (62) through the liquid side connecting tube (52) ( To 20).

また、室外熱交換器（23）は、蒸発器として機能する場合、液側接続管（52）から第１ヘッダ集合管（31）の補助連通空間（62）に流入した冷媒（液冷媒）が、補助熱交換部（35）の各補助熱交換領域（35a〜35c）、主熱交換部（34）の各主熱交換領域（34a〜34c）の順に通過して蒸発するように構成されている。 Further, when the outdoor heat exchanger (23) functions as an evaporator, the refrigerant (liquid refrigerant) flowing into the auxiliary communication space (62) of the first header collecting pipe (31) from the liquid side connecting pipe (52) The auxiliary heat exchange section (35) passes through each auxiliary heat exchange area (35a to 35c) and the main heat exchange section (34) passes through each main heat exchange area (34a to 34c) in this order to evaporate. Yes.

そして、本変形例の室外熱交換器（23）においても、上記実施形態と同様、過冷却割合Ｘ（過冷却度ＳＣ／温度差ΔＴ）が２０％〜８０％の範囲で、補助熱交割合Ｙが０％よりも高く且つ３５％以下に設定される。つまり、室外熱交換器（23）が凝縮器として機能する場合、図８に示すように、主熱交換部（34）の全体（即ち、三つの主熱交換領域（34a〜34c）の全体）がガス領域となり、補助熱交換部（35）の全体（即ち、三つの補助熱交換領域（35a〜35c）の全体）が液量域（過冷却領域）となるように、補助熱交割合Ｙが設定される。こうすることで、上記実施形態と同様の作用効果を奏する。 And also in the outdoor heat exchanger (23) of this modification, as with the above embodiment, the auxiliary heat exchange rate is within the range where the supercooling rate X (supercooling degree SC / temperature difference ΔT) is 20% to 80%. Y is set higher than 0% and 35% or less. That is, when the outdoor heat exchanger (23) functions as a condenser, as shown in FIG. 8, the entire main heat exchange section (34) (that is, the entire three main heat exchange regions (34a to 34c)). Becomes the gas region, and the auxiliary heat exchange ratio Y so that the entire auxiliary heat exchange section (35) (that is, the entire three auxiliary heat exchange regions (35a to 35c)) becomes the liquid amount region (supercooling region). Is set. By doing so, the same operational effects as the above-described embodiment can be obtained.

また、本変形例の室外熱交換器（23）では、順に冷媒が流通する主熱交換領域（34a〜34c）および補助熱交換領域（35a〜35c）の対を複数有し、複数の主熱交換領域（34a〜34c）が上下に並ぶ主熱交換部（34）と、複数の補助熱交換領域（35a〜35c）が上下に並ぶ補助熱交換部（35）とに区分されている。つまり、本変形例の室外熱交換器（23）では、複数の主熱交換領域（34a〜34c）が上下方向における片側（上側）へ集合して配列され、複数の補助熱交換領域（35a〜35c）が反対側の片側（下側）へ集合して配列されている。これにより、主熱交換領域と補助熱交換領域が互いに隣接する箇所を最少の１箇所に抑えることができる。つまり、本変形例の室外熱交換器（23）において、主熱交換領域（34a〜34c）と補助熱交換領域（35a〜35c）とが隣接する箇所は、主熱交換部（34）において最下に位置する第１主熱交換領域（34a）と補助熱交換部（35）において最上に位置する第３補助熱交換領域（35c）とが隣接する箇所のみである。 Further, the outdoor heat exchanger (23) of the present modification has a plurality of pairs of main heat exchange regions (34a to 34c) and auxiliary heat exchange regions (35a to 35c) through which the refrigerant flows in order, and a plurality of main heat The main heat exchange section (34) in which the exchange areas (34a to 34c) are arranged vertically and the auxiliary heat exchange section (35) in which the plurality of auxiliary heat exchange areas (35a to 35c) are arranged in the vertical direction are divided. That is, in the outdoor heat exchanger (23) of the present modification, a plurality of main heat exchange regions (34a to 34c) are arranged and arranged on one side (upper side) in the vertical direction, and a plurality of auxiliary heat exchange regions (35a to 35a) are arranged. 35c) are gathered and arranged on one side (lower side) of the opposite side. Thereby, the location where the main heat exchange region and the auxiliary heat exchange region are adjacent to each other can be suppressed to a minimum of one location. That is, in the outdoor heat exchanger (23) of the present modification, the portion where the main heat exchange region (34a to 34c) and the auxiliary heat exchange region (35a to 35c) are adjacent is the most in the main heat exchange part (34). The first main heat exchange region (34a) located below and the third auxiliary heat exchange region (35c) located at the top in the auxiliary heat exchange part (35) are only adjacent to each other.

そして、主熱交換領域（34a〜34c）を流通する冷媒の温度は、補助熱交換領域（35a〜35c）を流通する冷媒の温度よりも高い。そのため、互いに隣接する主熱交換領域の扁平管（33）と補助熱交換領域の扁平管（33）との間では、その隣接間のフィン（36）を通じて互いの冷媒同士が熱交換してしまい、その分冷媒と空気との間で交換する熱量が減少する。いわゆる熱ロスが生じる。その結果、室外熱交換器（23）の熱交換効率が低下してしまう。このような冷媒の熱ロスは、主熱交換領域と補助熱交換領域が互いに隣接する箇所が多いほど増大する。そのため、主熱交換領域と補助熱交換領域が互いに隣接する箇所が少ないほど、熱交換効率の低下を抑制することができる。この点、本変形例の室外熱交換器（23）によれば、主熱交換領域（34a〜34c）と補助熱交換領域（35a〜35c）との隣接箇所が最少の１箇所になるため、冷媒の熱ロスを最大限に抑制でき熱交換効率の低下を大幅に抑制することができる。 And the temperature of the refrigerant | coolant which distribute | circulates the main heat exchange area | region (34a-34c) is higher than the temperature of the refrigerant | coolant which distribute | circulates an auxiliary | assistant heat exchange area | region (35a-35c). Therefore, between the flat tubes (33) in the main heat exchange region and the flat tubes (33) in the auxiliary heat exchange region that are adjacent to each other, the refrigerants exchange heat with each other through the fins (36) between the adjacent ones. Accordingly, the amount of heat exchanged between the refrigerant and the air decreases. So-called heat loss occurs. As a result, the heat exchange efficiency of the outdoor heat exchanger (23) decreases. The heat loss of such a refrigerant increases as the number of places where the main heat exchange region and the auxiliary heat exchange region are adjacent to each other increases. Therefore, a decrease in heat exchange efficiency can be suppressed as the number of locations where the main heat exchange region and the auxiliary heat exchange region are adjacent to each other is smaller. In this respect, according to the outdoor heat exchanger (23) of the present modification, the adjacent portion between the main heat exchange region (34a to 34c) and the auxiliary heat exchange region (35a to 35c) is a minimum of one place. The heat loss of the refrigerant can be suppressed to the maximum, and the decrease in heat exchange efficiency can be greatly suppressed.

また、本変形例の補助熱交換部（35）では、各補助熱交換領域（35a〜35c）の扁平管（33）の本数を同一（三本ずつ）にしているため、各補助熱交換領域（35a〜35c）の冷媒の圧力損失が同等となる。 Moreover, in the auxiliary heat exchange part (35) of this modification, since the number of the flat tubes (33) of each auxiliary heat exchange area (35a-35c) is made the same (three pieces each), each auxiliary heat exchange area The pressure loss of the refrigerants (35a to 35c) is equivalent.

ここで、室外熱交換器（23）全体の扁平管（33）の本数に対する補助熱交換部（35）全体の扁平管（33）の本数の割合（補助熱交割合Ｙ）は３５％以下と低い。そのため、室外熱交換器（23）全体の冷媒の圧力損失（以下、単に圧力損失とも言う。）は、主熱交換部（34）の圧力損失よりも補助熱交換部（35）の圧力損失が支配的となる。この支配的度は、補助熱交割合Ｙが低くなるほど大きくなる。そのため、室外熱交換器（23）の冷媒の流量は、概ね補助熱交換部（35）の圧力損失に応じた流量となる。そして、補助熱交換部（35）では、上述したように各補助熱交換領域（35a〜35c）の圧力損失が互いに同等であることから、各補助熱交換領域（35a〜35c）の冷媒の流量も同等となり、これに伴い、各主熱交換領域（34a〜34c）34c）の冷媒の流量も同等となる。 Here, the ratio of the number of flat tubes (33) in the entire auxiliary heat exchanger (35) to the number of flat tubes (33) in the entire outdoor heat exchanger (23) (auxiliary heat exchange ratio Y) is 35% or less. Low. Therefore, the pressure loss of the refrigerant in the entire outdoor heat exchanger (23) (hereinafter also simply referred to as pressure loss) is greater than the pressure loss of the main heat exchange unit (34). Become dominant. This degree of dominance increases as the auxiliary heat exchange ratio Y decreases. Therefore, the flow rate of the refrigerant in the outdoor heat exchanger (23) is approximately a flow rate corresponding to the pressure loss of the auxiliary heat exchange unit (35). And in an auxiliary heat exchange part (35), since the pressure loss of each auxiliary heat exchange area (35a-35c) is mutually equal as above-mentioned, the flow volume of the refrigerant | coolant of each auxiliary heat exchange area (35a-35c) Accordingly, the flow rate of the refrigerant in each main heat exchange region (34a to 34c) 34c) is also equivalent.

この構成により、例えば、主熱交換部（34）において、風速が大きい主熱交換領域では風速が小さい主熱交換領域よりも扁平管（33）の本数を少なくして、各主熱交換領域（34a〜34c）の熱負荷を均一にすることが容易に成し得る。上述のように主熱交換部（34）の冷媒流量は補助熱交換部（35）の圧力損失に支配されるため、扁平管（33）の本数を少なくした主熱交換領域の冷媒流量は減少するがその減少量はごく僅かとなる。したがって、各主熱交換領域（34a〜34c）の冷媒流量は概ね同等のまま維持される。このように、風速分布に応じて各主熱交換領域（34a〜34c）の熱負荷を均一にする際、各主熱交換領域（34a〜34c）の冷媒流量のバランスを殆ど崩すことなく（各主熱交換領域（34a〜34c）の冷媒流量に殆ど影響を及ぼすことなく）成し得るので、熱負荷を均一にする設計が容易となる。 With this configuration, for example, in the main heat exchange section (34), the number of the flat tubes (33) is reduced in the main heat exchange area where the wind speed is large compared to the main heat exchange area where the wind speed is small, and each main heat exchange area ( It can be easily achieved to make the heat load of 34a to 34c) uniform. As described above, the refrigerant flow rate in the main heat exchange section (34) is governed by the pressure loss in the auxiliary heat exchange section (35), so the refrigerant flow rate in the main heat exchange area with a reduced number of flat tubes (33) decreases. However, the decrease is negligible. Therefore, the refrigerant flow rates in the main heat exchange regions (34a to 34c) are maintained substantially the same. As described above, when the heat load of each main heat exchange region (34a to 34c) is made uniform according to the wind speed distribution, the balance of the refrigerant flow rate in each main heat exchange region (34a to 34c) is hardly lost (each Therefore, it is easy to design a uniform heat load.

また、本変形例の室外熱交換器（23）では、液側接続管（52）の各細径管（52a〜52c）によって各補助熱交換領域（35a〜35c）の冷媒流量が調整される。本変形例では、上述したように各補助熱交換領域（35a〜35c）の圧力損失が同等であるため、三本共に管内径や管長がほぼ同仕様の細径管（52a〜52c）を用いることで、各補助熱交換領域（35a〜35c）の冷媒流量を同等にすることができる。これにより、細径管（52a〜52c）の設計が容易となる。 Moreover, in the outdoor heat exchanger (23) of this modification, the refrigerant | coolant flow rate of each auxiliary | assistant heat exchange area (35a-35c) is adjusted with each small diameter pipe | tube (52a-52c) of a liquid side connection pipe (52). . In this modification, the pressure loss of each auxiliary heat exchange region (35a to 35c) is the same as described above, and therefore, the small diameter tubes (52a to 52c) having the same specifications for the inner diameter and the length of the three tubes are used. Thereby, the refrigerant | coolant flow volume of each auxiliary | assistant heat exchange area | region (35a-35c) can be made equivalent. This facilitates the design of the small diameter tubes (52a to 52c).

以上説明したように、本発明は、複数の扁平管がヘッダ集合管に接続された熱交換器およびそれを備えた空気調和機について有用である。 As described above, the present invention is useful for a heat exchanger in which a plurality of flat tubes are connected to a header collecting tube and an air conditioner including the heat exchanger.

10 空気調和機
20 冷媒回路
23 室外熱交換器（熱交換器）
31 第１ヘッダ集合管
32 第２ヘッダ集合管
33 扁平管
34 主熱交換部
35 補助熱交換部
34a,34b,34c 主熱交換領域（熱交換領域）
35a,35b,35c 補助熱交換領域（熱交換領域）
61 主連通空間（連通空間）
62a,62b,62c 連通空間
71a,71b,71c,71d,71e 連通空間
72,73 連通管 10 Air conditioner
20 Refrigerant circuit
23 Outdoor heat exchanger (heat exchanger)
31 First header collecting pipe
32 Second header collecting pipe
33 Flat tube
34 Main heat exchanger
35 Auxiliary heat exchanger
34a, 34b, 34c Main heat exchange area (heat exchange area)
35a, 35b, 35c Auxiliary heat exchange area (heat exchange area)
61 Main communication space (communication space)
62a, 62b, 62c Communication space
71a, 71b, 71c, 71d, 71e Communication space
72,73 communication pipe

Claims

A plurality of flat tubes (33) arranged in a direction perpendicular to the tube axis, and a first header collecting tube (31) and a second header collecting tube (32) connected to both ends of each flat tube (33) A heat exchanger that is connected to a refrigerant circuit that circulates the refrigerant in a reversible manner and performs a refrigeration cycle to exchange heat between the refrigerant and air,
The plurality of flat tubes (33) are divided into a main heat exchanging portion (34) and an auxiliary heat exchanging portion (35) in the arrangement direction, and when functioning as a condenser, a refrigerant is used for the main heat exchanging portion (34). ) To the auxiliary heat exchanger (35) in this order, and when functioning as an evaporator, the refrigerant is configured to pass from the auxiliary heat exchanger (35) to the main heat exchanger (34) in this order,
Supercooling of refrigerant flowing out from the auxiliary heat exchanger (35) to the header collecting pipe (31, 32) with respect to a temperature difference ΔT between the refrigerant condensing temperature and the temperature of air before heat exchange when functioning as a condenser The ratio of the heat transfer area of the flat tube (33) of the auxiliary heat exchange part (35) to the total heat transfer area of the plurality of flat tubes (33) is 20% to 80%. A heat exchanger characterized by being set to be higher than 0% and not higher than 35%.

In claim 1,
The plurality of flat tubes (33) have the same heat transfer area.
When the refrigerant functions as a condenser, the refrigerant flowing out from the auxiliary heat exchanger (35) to the header collecting pipe (31, 32) with respect to the temperature difference ΔT between the refrigerant condensing temperature and the air temperature before heat exchange. The ratio of the number of flat tubes (33) of the auxiliary heat exchange part (35) to the total number of the plurality of flat tubes (33) is less than 0% in the range of the supercooling degree SC in the range of 20% to 80%. And is set to 35% or less.

In claim 1 or 2,
The main heat exchange section (34) and the auxiliary heat exchange section (35) are divided into a plurality of and the same number of heat exchange areas (34a to 34c, 35a to 35c) in the arrangement direction of the flat tubes (33),
In the first header collecting pipe (31), the internal space is partitioned in the arrangement direction of the flat pipe (33), so that all the heat exchanging areas (34a to 34c) of the main heat exchanging section (34) are provided. A corresponding single communication space (61) and the same number of communication spaces (62a to 35a) as the heat exchange regions (35a to 35c) corresponding to the heat exchange regions (35a to 35c) of the auxiliary heat exchange unit (35). 62c) is formed,
In the second header collecting pipe (32), the internal space is partitioned in the arrangement direction of the flat tubes (33), so that the heat exchanging area (34a) of the main heat exchanging section (34) adjacent to each other and the above The heat exchange regions (34b, 34c, 35a, 35b) corresponding to the heat exchange regions (34b, 34c, 35a, 35b) of both the heat exchange units (34, 35) excluding the heat exchange region (35c) of the auxiliary heat exchange unit (35) 34c, 35a, 35b) and the same number of communication spaces (71a, 71b, 71d, 71e) are formed, and the heat exchange region (34a) of the adjacent main heat exchange part (34) and the auxiliary heat exchange are formed. A single communication space (71c) corresponding to the heat exchange area (35c) of the portion (35) is formed,
The second header collecting pipe (32) has a common heat exchange area (34a) of the main heat exchange section (34) adjacent to each other and a heat exchange area (35c) of the auxiliary heat exchange section (35). Each communication space (71d, 71e) of the main heat exchange part (34) excluding a corresponding single communication space (71c) and each communication space (71a, 71b) of the auxiliary heat exchange part (35) A heat exchanger characterized in that communication pipes (72, 73) are provided which are paired together and connect the communication spaces to be paired.

In claim 3,
In the auxiliary heat exchanging section (35), the total flow path cross-sectional areas of the flat tubes (33) of the heat exchanging regions (35a to 35c) are the same as each other.

A refrigerant circuit (20) provided with the heat exchanger (23) according to any one of claims 1 to 4,
An air conditioner that performs a refrigeration cycle by reversibly circulating refrigerant in the refrigerant circuit (20).