JP6990795B1

JP6990795B1 - Indoor unit and outdoor unit

Info

Publication number: JP6990795B1
Application number: JP2021109971A
Authority: JP
Inventors: 政▲眠▼ 李; 賢治松村; 修平多田; 宏治内藤
Original assignee: Hitachi Johnson Controls Air Conditioning Inc
Current assignee: Hitachi Johnson Controls Air Conditioning Inc
Priority date: 2021-01-28
Filing date: 2021-07-01
Publication date: 2022-01-12
Anticipated expiration: 2041-01-28
Also published as: JP2022115781A

Abstract

【課題】交換のための冷媒として非共沸混合冷媒を用いた場合の熱交換性能を向上させることを目的とする。【解決手段】非共沸混合冷媒を用いる空気調和機であって、蒸発器及び凝縮器として動作可能な熱交換器を備え、熱交換器内の冷媒流路は、熱交換器が蒸発器として動作する場合の冷媒入口側である蒸発器入口側における冷媒の流れる方向が空気の流れに対して並行流となるように、蒸発器入口側において、空気の流れる方向に設けられた複数列の伝熱管を通過し、かつ熱交換器が蒸発器として動作する場合の冷媒出口側である蒸発器出口側において、前記複数の列の伝熱管の情報に設けられた１列の伝熱管を通過するように設けられ、蒸発器出口は、蒸発器入口よりも鉛直方向の上側に設けられる。【選択図】図２PROBLEM TO BE SOLVED: To improve heat exchange performance when a non-azeotropic mixed refrigerant is used as a refrigerant for replacement. SOLUTION: This is an air conditioner using a non-co-boiling mixed refrigerant, comprising a heat exchanger that can operate as an evaporator and a condenser, and the refrigerant flow path in the heat exchanger is such that the heat exchanger acts as an evaporator. Multiple rows of transmissions provided in the direction of air flow on the evaporator inlet side so that the flow direction of the refrigerant on the evaporator inlet side, which is the refrigerant inlet side when operating, is parallel to the air flow. Pass through the heat pipes and on the evaporator outlet side, which is the refrigerant outlet side when the heat exchanger operates as an evaporator, to pass through one row of heat transfer tubes provided in the information of the plurality of rows of heat transfer tubes. The evaporator outlet is provided on the upper side in the vertical direction with respect to the evaporator inlet. [Selection diagram] Fig. 2

Description

本発明は、室内機及び室外機に関する。 The present invention relates to an indoor unit and an outdoor unit .

空気調和機においては、地球温暖化防止のため、ＧＷＰ（Global Warming Potential：地球温暖化係数）が低い冷媒を使う必要がある。低ＧＷＰ冷媒として、非共沸混合冷媒が多く提案されている。非共沸混合冷媒は、単一冷媒と違い、組成成分それぞれの沸点の違いから温度勾配があるため、同じ圧力で乾き度が大きくなるにつれて、温度が上昇する。このため、凝縮器基準で冷媒と空気の流れを対向流にし、蒸発器として利用する場合には、空気と冷媒との温度差を取るのが難しい。これに対し、特許文献１には、熱交換器を蒸発器あるいは凝縮器として利用する場合に、空気流に対して冷媒の流れが並行流となる伝熱管と、対向流となる伝熱管とを備える技術が開示されている。 In an air conditioner, it is necessary to use a refrigerant having a low GWP (Global Warming Potential) in order to prevent global warming. As a low GWP refrigerant, many non-azeotropic mixed refrigerants have been proposed. Unlike a single refrigerant, the non-azeotropic mixed refrigerant has a temperature gradient due to the difference in boiling point of each composition component, so that the temperature rises as the dryness increases at the same pressure. Therefore, when the flow of the refrigerant and the air is countercurrent on the basis of the condenser and used as an evaporator, it is difficult to take the temperature difference between the air and the refrigerant. On the other hand, in Patent Document 1, when the heat exchanger is used as an evaporator or a condenser, a heat transfer tube in which the flow of the refrigerant is parallel to the air flow and a heat transfer tube in which the flow of the refrigerant is countercurrent are described. The technology to be provided is disclosed.

特開２００２－１９５６７５号公報Japanese Unexamined Patent Publication No. 2002-195675

特許文献１の技術においては、熱交換器が蒸発器として動作する場合に、対向流となる区間では、風上側の熱交換器列に対し風下側の熱交換器列は、同じ蒸発圧力の場合に、冷媒温度が下がり、冷媒と空気に温度差があるため、熱交換性能の低下を抑制することができる。しかしながら、蒸発器として動作する場合に対向流となる区間は、熱交換器が凝縮器として動作する場合には並行流となる。このため、風上側の熱交換器列において冷媒ガスと熱交換した空気が、風下側の熱交換列を通過する際には、冷媒と空気の温度差が確保されない可能性がある。また、空気と風上側の熱交換列で２相冷媒と熱交換した後の空気が風下側の熱交換器列で低乾き度の冷媒と熱交換する際に温度が確保されず、単一冷媒相当の過冷却を達成できない可能性がある。これらのことから、熱交換性能が大幅に低下し、空気調和機の総合的な性能低下に繋がる可能性があるという問題があった。 In the technique of Patent Document 1, when the heat exchanger operates as an evaporator, in the section where the countercurrent flow occurs, the heat exchanger row on the leeward side has the same evaporation pressure as the heat exchanger row on the wind side. In addition, since the refrigerant temperature drops and there is a temperature difference between the refrigerant and air, it is possible to suppress the deterioration of heat exchange performance. However, the section that becomes a countercurrent when operating as an evaporator becomes a parallel flow when the heat exchanger operates as a condenser. Therefore, when the air that has exchanged heat with the refrigerant gas in the heat exchanger row on the leeward side passes through the heat exchange row on the leeward side, the temperature difference between the refrigerant and the air may not be secured. In addition, the temperature is not secured when the air after heat exchange with the two-phase refrigerant in the heat exchange row on the leeward side exchanges heat with the low-dryness refrigerant in the heat exchanger row on the leeward side, and a single refrigerant is used. It may not be possible to achieve significant overcooling. From these facts, there is a problem that the heat exchange performance is significantly deteriorated, which may lead to the overall performance deterioration of the air conditioner.

本発明は、このような問題点に鑑みなされたもので、熱交換のための冷媒として非共沸混合冷媒を用いた場合の熱交換性能を向上させることを目的とする。 The present invention has been made in view of such problems, and an object of the present invention is to improve heat exchange performance when a non-azeotropic mixed refrigerant is used as a refrigerant for heat exchange.

本発明は、非共沸混合冷媒を用いる室内機であって、蒸発器及び凝縮器として動作可能な熱交換器を備え、前記熱交換器内の冷媒流路は、前記熱交換器が前記蒸発器として動作する場合の冷媒入口側である蒸発器入口側における冷媒の流れる方向が空気の流れに対して並行流となるように、前記蒸発器入口側において、空気の流れる方向に設けられた複数列の伝熱管を通過し、かつ前記熱交換器が前記蒸発器として動作する場合の冷媒出口側である蒸発器出口側において、前記複数の列の伝熱管の上方に設けられた１列の伝熱管を通過するように設けられ、前記蒸発器出口は、前記蒸発器入口よりも鉛直方向の上側に設けられる。
本発明の他の形態は、非共沸混合冷媒を用いる室内機であって、蒸発器及び凝縮器として動作可能な熱交換器を備え、前記熱交換器内の冷媒流路は、前記熱交換器が前記蒸発器として動作する場合の冷媒入口側である蒸発器入口側における冷媒の流れる方向が空気の流れに対して並行流となるように、前記蒸発器入口側において、空気の流れる方向に設けられた複数列の伝熱管を通過し、かつ前記熱交換器が前記蒸発器として動作する場合の冷媒出口側である蒸発器出口側において、前記複数の列の伝熱管の上方に設けられた１列の伝熱管を通過するように設けられ、前記熱交換器は、前記複数列の伝熱管に対応した伝熱面積が、前記１列の伝熱管に対応した伝熱面積以下となるように形成される。 The present invention is an indoor unit using a non-cobo-boiling mixed refrigerant, comprising a heat exchanger that can operate as an evaporator and a condenser, and the refrigerant flow path in the heat exchanger is such that the heat exchanger evaporates. A plurality of units provided in the direction of air flow on the evaporator inlet side so that the flow direction of the refrigerant on the evaporator inlet side, which is the refrigerant inlet side when operating as a vessel, is parallel to the air flow. One row of heat transfer tubes provided above the plurality of rows of heat transfer tubes on the evaporator outlet side, which is the refrigerant outlet side when the heat exchanger operates as the refrigerant while passing through the heat transfer tubes in the rows. It is provided so as to pass through the heat pipe, and the evaporator outlet is provided on the upper side in the vertical direction with respect to the evaporator inlet.
Another embodiment of the present invention is an indoor unit using a non-coborous mixed refrigerant, comprising a heat exchanger that can operate as an evaporator and a condenser, and the refrigerant flow path in the heat exchanger is the heat exchange. In the direction of air flow on the evaporator inlet side, the flow direction of the refrigerant on the evaporator inlet side, which is the refrigerant inlet side when the vessel operates as the evaporator, is parallel to the air flow. It is provided above the plurality of rows of heat transfer tubes on the evaporator outlet side, which is the refrigerant outlet side when the heat exchanger operates as the evaporator while passing through the provided plurality of rows of heat transfer tubes. The heat exchanger is provided so as to pass through one row of heat transfer tubes so that the heat transfer area corresponding to the plurality of rows of heat transfer tubes is equal to or less than the heat transfer area corresponding to the one row of heat transfer tubes. It is formed.

本発明の他の形態は、非共沸混合冷媒を用いる室外機であって、蒸発器及び凝縮器として動作可能な熱交換器を備え、前記熱交換器内の冷媒流路は、前記熱交換器が前記蒸発器として動作する場合の冷媒入口側である蒸発器入口側における冷媒の流れる方向が空気の流れに対して並行流となるように、前記蒸発器入口側において、空気の流れる方向に設けられた複数列の伝熱管を通過し、かつ前記熱交換器が前記蒸発器として動作する場合の冷媒出口側である蒸発器出口側において、前記複数の列の伝熱管の上方に設けられた１列の伝熱管を通過するように設けられ、前記蒸発器出口は、前記蒸発器入口よりも鉛直方向の上側に設けられる。
本発明の他の形態は、非共沸混合冷媒を用いる室外機であって、蒸発器及び凝縮器として動作可能な熱交換器を備え、前記熱交換器内の冷媒流路は、前記熱交換器が前記蒸発器として動作する場合の冷媒入口側である蒸発器入口側における冷媒の流れる方向が空気の流れに対して並行流となるように、前記蒸発器入口側において、空気の流れる方向に設けられた複数列の伝熱管を通過し、かつ前記熱交換器が前記蒸発器として動作する場合の冷媒出口側である蒸発器出口側において、前記複数の列の伝熱管の上方に設けられた１列の伝熱管を通過するように設けられ、前記複数列の伝熱管に対応した伝熱面積が、前記１列の伝熱管に対応した伝熱面積以下となるように形成される。
Another embodiment of the present invention is an outdoor unit using a non-cobo-boiling mixed refrigerant , comprising a heat exchanger that can operate as an evaporator and a condenser, and the refrigerant flow path in the heat exchanger is the heat exchange. In the direction of air flow on the evaporator inlet side, the flow direction of the refrigerant on the refrigerant inlet side, which is the refrigerant inlet side when the vessel operates as the evaporator, is parallel to the air flow. It is provided above the plurality of rows of heat transfer tubes on the evaporator outlet side, which is the refrigerant outlet side when the heat exchanger operates as the evaporator while passing through the plurality of rows of heat transfer tubes provided. It is provided so as to pass through a row of heat transfer tubes, and the evaporator outlet is provided on the upper side in the vertical direction with respect to the evaporator inlet.
Another embodiment of the present invention is an outdoor unit using a non-co-boiling mixed refrigerant , comprising a heat exchanger that can operate as an evaporator and a condenser, and the refrigerant flow path in the heat exchanger is the heat exchange. In the direction of air flow on the evaporator inlet side, the flow direction of the refrigerant on the evaporator inlet side, which is the refrigerant inlet side when the vessel operates as the evaporator, is parallel to the air flow. It is provided above the plurality of rows of heat transfer tubes on the evaporator outlet side, which is the refrigerant outlet side when the heat exchanger operates as the evaporator while passing through the provided plurality of rows of heat transfer tubes. It is provided so as to pass through one row of heat transfer tubes, and is formed so that the heat transfer area corresponding to the plurality of rows of heat transfer tubes is equal to or less than the heat transfer area corresponding to the one row of heat transfer tubes.

本発明によれば、熱交換のための冷媒として非共沸混合冷媒を用いた場合の熱交換性能を向上させることができる。 According to the present invention, it is possible to improve the heat exchange performance when a non-azeotropic mixed refrigerant is used as the refrigerant for heat exchange.

空気調和機の全体図である。It is an overall view of an air conditioner. 熱交換器を模式的に示す図である。It is a figure which shows the heat exchanger schematically. ｐ－ｈ線図を示す図である。It is a figure which shows the ph diagram. 伝熱管内冷媒の温度変化を示す図である。It is a figure which shows the temperature change of the refrigerant in a heat transfer tube. ２列部伝熱面積の割合と、効率増加率との関係を示すグラフを示す図である。It is a figure which shows the graph which shows the relationship between the ratio of the heat transfer area of a two-row part, and the efficiency increase rate. 第２の変形例に係る熱交換器を模式的に示す図である。It is a figure which shows typically the heat exchanger which concerns on the 2nd modification. 第３の変形例に係る熱交換器を模式的に示す図である。It is a figure which shows typically the heat exchanger which concerns on the 3rd modification. 第３の変形例に係る熱交換器を模式的に示す図である。It is a figure which shows typically the heat exchanger which concerns on the 3rd modification. 扁平管を用いた熱交換器における流路面積の説明図である。It is explanatory drawing of the flow path area in a heat exchanger using a flat tube. 第６の変形例に係る熱交換器を模式的に示す図である。It is a figure which shows typically the heat exchanger which concerns on the 6th modification.

図１は、実施形態に係る空気調和機１の全体図である。空気調和機１は、冷凍サイクル（ヒートポンプサイクル）で冷媒を循環させることによって、空調を行う。本実施形態の空気調和機１においては、熱交換のための冷媒として非共沸混合冷媒が用いられる。図１に示すように、空気調和機１は、屋外（室外）に設置される室外機１０と、室内（被空調空間）に設置される室内機２０と、を備えている。 FIG. 1 is an overall view of the air conditioner 1 according to the embodiment. The air conditioner 1 performs air conditioning by circulating a refrigerant in a refrigeration cycle (heat pump cycle). In the air conditioner 1 of the present embodiment, a non-azeotropic mixed refrigerant is used as the refrigerant for heat exchange. As shown in FIG. 1, the air conditioner 1 includes an outdoor unit 10 installed outdoors (outdoors) and an indoor unit 20 installed indoors (air-conditioned space).

室外機１０は、圧縮機１１と、四方弁１２と、アキュムレータ１３と、室外熱交換器１１４と、室外ファン１５と、室外膨張弁１６と、を有している。圧縮機１１は、低温低圧のガス冷媒を圧縮し、高温高圧のガス冷媒として吐出する機器である。室外熱交換器１４において、冷凍サイクルを循環する冷媒と、室外ファン１５から送り込まれる外気と、の間で熱交換が行われる。室外熱交換器１４は、四方弁１２の切り替えにより凝縮器及び蒸発器として動作する。 The outdoor unit 10 includes a compressor 11, a four-way valve 12, an accumulator 13, an outdoor heat exchanger 114, an outdoor fan 15, and an outdoor expansion valve 16. The compressor 11 is a device that compresses a low-temperature low-pressure gas refrigerant and discharges it as a high-temperature high-pressure gas refrigerant. In the outdoor heat exchanger 14, heat exchange is performed between the refrigerant circulating in the refrigeration cycle and the outside air sent from the outdoor fan 15. The outdoor heat exchanger 14 operates as a condenser and an evaporator by switching the four-way valve 12.

室内機２０は、室内熱交換器２１と、室内ファン２２、を有している。室内熱交換器２１において、冷凍サイクルを循環する冷媒と、室内ファン２２から送り混まれる室内空気と、の間で熱交換が行われる。室内熱交換器２１は、四方弁１２の切り替えにより凝縮器及び蒸発器として動作する。なお、他の例としては、空気調和機１がビル用マルチエアコン等の場合には、室内機２０は、室内熱交換器２１から延びる冷媒管２及び室外膨張弁１６から延びる冷媒管２と接続する室内膨張弁２３をさらに備えてもよい。 The indoor unit 20 has an indoor heat exchanger 21 and an indoor fan 22. In the indoor heat exchanger 21, heat exchange is performed between the refrigerant circulating in the refrigeration cycle and the indoor air sent and mixed from the indoor fan 22. The indoor heat exchanger 21 operates as a condenser and an evaporator by switching the four-way valve 12. As another example, when the air conditioner 1 is a multi air conditioner for a building or the like, the indoor unit 20 is connected to the refrigerant pipe 2 extending from the indoor heat exchanger 21 and the refrigerant pipe 2 extending from the outdoor expansion valve 16. An indoor expansion valve 23 may be further provided.

冷房運転では、実線矢印で示すように、圧縮機１１より吐出された高温高圧のガス冷媒は、室外熱交換器１４に送られ、室外熱交換器１４に付設された室外ファン１５の駆動により室外空気と熱交換して凝縮し、高圧の液冷媒となる。液冷媒は、全開の室外膨張弁１６を通過し、冷媒管２を通じて室内機２０に送られる。そして、液冷媒は、室内熱交換器２１で、付設された室内ファン２２の駆動により室内空気と熱交換して低圧低温のガス冷媒となり、四方弁１２、アキュムレータ１３を通り圧縮機１１に戻る。 In the cooling operation, as shown by the solid line arrow, the high-temperature and high-pressure gas refrigerant discharged from the compressor 11 is sent to the outdoor heat exchanger 14, and is driven by the outdoor fan 15 attached to the outdoor heat exchanger 14 to be outdoors. It exchanges heat with air and condenses to become a high-pressure liquid refrigerant. The liquid refrigerant passes through the fully opened outdoor expansion valve 16 and is sent to the indoor unit 20 through the refrigerant pipe 2. Then, the liquid refrigerant exchanges heat with the indoor air by the drive of the attached indoor fan 22 in the indoor heat exchanger 21, becomes a low-pressure low-temperature gas refrigerant, passes through the four-way valve 12 and the accumulator 13, and returns to the compressor 11.

一方、暖房運転では、破線矢印で示すように、圧縮機１１で圧縮された高圧ガス冷媒が四方弁１２を通り、冷媒管２を通して、室内機２０の室内熱交換器２１に供給される。ガス冷媒は、室内熱交換器２１で室内空気を加熱しながら凝縮されて液冷媒となり、冷媒管２を通じて室外機１０に戻る。その後、冷媒は室外膨張弁１６を通り、室外熱交換器１４で室外空気と熱交換をすることで蒸発してガス冷媒となり、四方弁１２、アキュムレータ１３を通り、圧縮機１１に戻る。 On the other hand, in the heating operation, as shown by the broken line arrow, the high-pressure gas refrigerant compressed by the compressor 11 passes through the four-way valve 12 and is supplied to the indoor heat exchanger 21 of the indoor unit 20 through the refrigerant pipe 2. The gas refrigerant is condensed while heating the indoor air by the indoor heat exchanger 21 to become a liquid refrigerant, and returns to the outdoor unit 10 through the refrigerant pipe 2. After that, the refrigerant passes through the outdoor expansion valve 16 and evaporates by exchanging heat with the outdoor air in the outdoor heat exchanger 14, becomes a gas refrigerant, passes through the four-way valve 12 and the accumulator 13, and returns to the compressor 11.

図２は、室外熱交換器１４及び室内熱交換器２１として用いられる熱交換器３０を模式的に示す図である。なお、図２に示す３次元座標におけるＸ軸方向（紙面の奥行方向）を熱交換器３０の横方向、Ｙ軸方向（紙面の縦方向）を熱交換器３０の上下方向（紙面上側が上方向）、Ｚ軸方向（紙面の横方向）を熱交換器３０の奥行方向とする。熱交換器３０は、室外機１０及び室内機２０が設置された状態において、熱交換器３０の上下方向が鉛直方向に沿うように設けられる。また、ファン（室外ファン１５、室内ファン２２）により空気の流れる方向を矢印Ａで示す。熱交換器３０のうち紙面において左側が風上側、右側が風下側となる。 FIG. 2 is a diagram schematically showing a heat exchanger 30 used as an outdoor heat exchanger 14 and an indoor heat exchanger 21. The X-axis direction (depth direction of the paper surface) in the three-dimensional coordinates shown in FIG. 2 is the horizontal direction of the heat exchanger 30, and the Y-axis direction (vertical direction of the paper surface) is the vertical direction of the heat exchanger 30 (the upper side of the paper surface is up). The direction) and the Z-axis direction (horizontal direction of the paper surface) are defined as the depth direction of the heat exchanger 30. The heat exchanger 30 is provided so that the vertical direction of the heat exchanger 30 is along the vertical direction in a state where the outdoor unit 10 and the indoor unit 20 are installed. Further, the direction in which air flows by the fans (outdoor fan 15, indoor fan 22) is indicated by an arrow A. Of the heat exchanger 30, the left side is the windward side and the right side is the leeward side on the paper surface.

熱交換器３０は、複数の伝熱管３１と、複数のフィン３２とを有している。フィン３２は、その面方向がＸ軸に垂直になるように設けられている。図２においては、１つのフィン３２のみを示しているが、複数のフィン３２が一定の間隔でＸ軸方向に配置されている。複数の伝熱管３１は、フィン３２を貫通するように設けられている。 The heat exchanger 30 has a plurality of heat transfer tubes 31 and a plurality of fins 32. The fin 32 is provided so that its surface direction is perpendicular to the X axis. Although only one fin 32 is shown in FIG. 2, a plurality of fins 32 are arranged at regular intervals in the X-axis direction. The plurality of heat transfer tubes 31 are provided so as to penetrate the fins 32.

さらに、熱交換器３０の下側の領域には、空気の流れる方向Ａに沿って２列の伝熱管３１が配設されている。また、熱交換器３０の上側の領域においては、空気の流れる方向Ａに沿って１列の伝熱管３１が配設されている。以下においては、２列の伝熱管が配設された領域を２列部３２２と称し、１列の伝熱管が配設された領域を１列部３２１と称する。また、２列部３２２のうち、風上側の列を風上列３３１と称し、風下側の列を風下列３３２と称する。１列部３２１の伝熱管３１には、その内側の断面積Ｍ１が、２列部３２２の伝熱管３１の内側の断面積Ｍ２よりも大きいものが用いられる。 Further, in the lower region of the heat exchanger 30, two rows of heat transfer tubes 31 are arranged along the air flow direction A. Further, in the upper region of the heat exchanger 30, a row of heat transfer tubes 31 is arranged along the air flow direction A. In the following, a region in which two rows of heat transfer tubes are arranged is referred to as a two-row portion 322, and a region in which one row of heat transfer tubes is arranged is referred to as a one-row portion 321. Further, of the two rows 322, the row on the leeward side is referred to as the leeward row 331, and the row on the leeward side is referred to as the leeward row 332. As the heat transfer tube 31 of the first row portion 321, a heat transfer tube 31 having an inner cross-sectional area M1 larger than the inner cross-sectional area M2 of the heat transfer tube 31 of the second row portion 322 is used.

熱交換器３０は、２列部３２２と、１列部３２１のすべての伝熱管３１とフィン３２が一体に形成されたものとする。ただし、他の例としては、１列部３２１のユニットと、風上列３３１のユニットと、風下列３３２のユニット、というように、複数のユニットを組み合わせることで熱交換器３０が形成されてもよい。 In the heat exchanger 30, it is assumed that the two-row portion 322, all the heat transfer tubes 31 of the one-row portion 321 and the fins 32 are integrally formed. However, as another example, even if the heat exchanger 30 is formed by combining a plurality of units such as a unit of the one row portion 321 and a unit of the upwind row 331 and a unit of the leeward row 332. good.

伝熱管３１の第１冷媒出入口３１１は、風上側に設けられ、冷媒管２を介して膨張弁（室外膨張弁１６）に接続する。伝熱管３１の第２冷媒出入口３１２は、1列部３２１の上側に設けられ、四方弁１２及びアキュムレータ１３を介して圧縮機１１に接続する。熱交換器３０において、伝熱管３１の第１冷媒出入口３１１及び第２冷媒出入口３１２は、それぞれ、熱交換器３０が蒸発器として動作する場合に、冷媒入口及び冷媒出口となる。以下、蒸発器として動作する場合の冷媒入口及び冷媒出口をそれぞれ蒸発器入口及び蒸発器出口と称する。 The first refrigerant inlet / outlet 311 of the heat transfer pipe 31 is provided on the windward side and is connected to the expansion valve (outdoor expansion valve 16) via the refrigerant pipe 2. The second refrigerant inlet / outlet 312 of the heat transfer tube 31 is provided on the upper side of the first row portion 321 and is connected to the compressor 11 via the four-way valve 12 and the accumulator 13. In the heat exchanger 30, the first refrigerant inlet / outlet 311 and the second refrigerant inlet / outlet 312 of the heat transfer tube 31 become a refrigerant inlet and a refrigerant outlet, respectively, when the heat exchanger 30 operates as an evaporator. Hereinafter, the refrigerant inlet and the refrigerant outlet when operating as an evaporator are referred to as an evaporator inlet and an evaporator outlet, respectively.

熱交換器３０が蒸発器として動作する場合に、蒸発器入口（第１冷媒出入口３１１）から風下に向かい、２列部３２２の端部３１３から、１列部３２１の下側の端部３１４へ入り、１列部３２１を経由して、蒸発器出口（第２冷媒出入口３１２）へ向かう冷媒経路が形成されている。なお、熱交換器３０が凝縮器として動作する場合には、この冷媒流路を熱交換器３０が蒸発器として動作する場合と逆向きに冷媒が流れる。 When the heat exchanger 30 operates as an evaporator, it goes downwind from the evaporator inlet (first refrigerant inlet / outlet 311) and goes from the end 313 of the second row portion 322 to the lower end 314 of the first row portion 321. A refrigerant path is formed which enters and goes to the evaporator outlet (second refrigerant inlet / outlet 312) via the first row portion 321. When the heat exchanger 30 operates as a condenser, the refrigerant flows in the refrigerant flow path in the opposite direction to the case where the heat exchanger 30 operates as an evaporator.

このような冷媒流路においては、熱交換器３０が凝縮器として動作する場合に、蒸発器入口側、すなわち２列部３２２において、冷媒の流れが空気の流れに対して対向流となる。したがって、凝縮器として動作する場合の熱交換効率を向上させることができる。また、従来例のように、熱交換器３０を蒸発器として動作させた場合に、蒸発器出口側が対向流となるようにした場合には、熱交換器３０を凝縮器として動作させた場合に、蒸発器出口側の冷媒の流れが並行流となり、熱交換効率が低下してしまう。これに対し、本実施形態においては、蒸発器出口側を１列の伝熱管とすることで、凝縮器としての性能が低下するのを防ぐことができる。 In such a refrigerant flow path, when the heat exchanger 30 operates as a condenser, the flow of the refrigerant is countercurrent to the flow of air on the evaporator inlet side, that is, in the two-row portion 322. Therefore, it is possible to improve the heat exchange efficiency when operating as a condenser. Further, as in the conventional example, when the heat exchanger 30 is operated as an evaporator and the outlet side of the evaporator is countercurrent, the heat exchanger 30 is operated as a condenser. , The flow of the refrigerant on the outlet side of the evaporator becomes a parallel flow, and the heat exchange efficiency is lowered. On the other hand, in the present embodiment, by using a single row of heat transfer tubes on the outlet side of the evaporator, it is possible to prevent the performance of the condenser from deteriorating.

さらに、熱交換器３０においては、蒸発器としての性能の低下を防ぐため、圧力損失による温度低下が非共沸混合冷媒の温度勾配による温度上昇に比べて優勢になるように、２列部３２２の伝熱管３１の断面積Ｍ２が設計されている。ここで、温度勾配とは、熱交換器での蒸発又は凝縮における開始温度と終了温度が異なることである。圧力損失が大きくなると、圧力損失による温度低下が温度勾配による温度上昇に比べて優勢となる。このように圧力損失が優勢となる結果、蒸発器入口から伝熱管を流れるにつれて冷媒の温度が徐々に低下する。すなわち、蒸発器入口から、空気の流れに沿って、冷媒の温度が低下する。これにより、風上から風下に向かう方向において、空気と冷媒の温度差を同程度とすることができる。このため、風上側及び風下側の伝熱管がいずれも熱交換に有効に利用され、熱交換の効率を向上させることができる。 Further, in the heat exchanger 30, in order to prevent the performance as an evaporator from deteriorating, the temperature decrease due to the pressure loss becomes dominant over the temperature increase due to the temperature gradient of the non-co-boiling mixed refrigerant. The cross-sectional area M2 of the heat transfer tube 31 is designed. Here, the temperature gradient means that the start temperature and the end temperature in evaporation or condensation in the heat exchanger are different. When the pressure loss becomes large, the temperature decrease due to the pressure loss becomes dominant over the temperature increase due to the temperature gradient. As a result of the predominance of pressure loss in this way, the temperature of the refrigerant gradually decreases as it flows from the evaporator inlet to the heat transfer tube. That is, the temperature of the refrigerant drops from the evaporator inlet along the flow of air. As a result, the temperature difference between the air and the refrigerant can be made about the same in the direction from the windward to the leeward. Therefore, both the windward and leeward heat transfer tubes are effectively used for heat exchange, and the efficiency of heat exchange can be improved.

さらに、１列部３２１の伝熱管として、その断面積Ｍ１が２列部３２２の断面積Ｍ２よりも大きいものが用いられる。すなわち、１列部３２１の流路面積は、２列部３２２の流路面積よりも大きくなる。これにより、１列部３２１において冷媒の流速が遅くなり、圧力損失が小さくなる。したがって、２列部３２１においては、非共沸混合冷媒の温度勾配による温度上昇が圧力損失による温度上昇に比べて優勢になり、１列部３２１において圧力損失が増加することによる、蒸発器としての熱交換性能の低下を防ぐことができる。 Further, as the heat transfer tube of the one-row portion 321, a tube having a cross-sectional area M1 larger than the cross-sectional area M2 of the two-row portion 322 is used. That is, the flow path area of the first row portion 321 is larger than the flow path area of the second row portion 322. As a result, the flow velocity of the refrigerant becomes slower in the first row portion 321 and the pressure loss becomes smaller. Therefore, in the second row portion 321 the temperature rise due to the temperature gradient of the non-azeotropic mixed refrigerant becomes dominant over the temperature rise due to the pressure loss, and the pressure loss increases in the first row portion 321 as an evaporator. It is possible to prevent deterioration of heat exchange performance.

図３は、ｐ－ｈ線図を示す図である。グラフの横軸及び縦軸は、それぞれ比エンタルピー及び圧力を示す。実線は、本実施形態の冷凍サイクルを模式的に示している。またＴ１、Ｔ２は、等温線の一部である。図中の冷凍サイクルでの各状態を説明する。図中においてＨ１は圧縮機吸入、Ｈ２は圧縮機吐出および凝縮器入口、Ｈ３は凝縮器出口、Ｈ４は蒸発器入口、Ｈ５は蒸発器入口部と蒸発器出口の中間部を示している。このような順序で冷媒状態が変化し冷凍サイクルが形成される。熱交換のための冷媒として非共沸混合冷媒を用いることから、圧力が一定の場合、冷媒蒸発時に温度が上昇する。しかしながら、前述の通り、蒸発器入口側では、非共沸混合冷媒の温度勾配に対し圧力損失が優勢となることに起因して、温度が低下する。図３におけるＳ１の範囲は、この圧力損失に起因して、冷媒の温度が徐々に低下する蒸発器入口側の領域である。Ｓ１の範囲は、熱交換器３０が蒸発器として動作する場合に並行流となる、２列部３２２の伝熱管３１に対応する。また、Ｓ２の範囲は、圧力損失よりも非共沸混合冷媒の温度勾配が優勢となり、冷媒の温度が徐々に上昇する蒸発器出口側の領域である。Ｓ２の範囲は、１列部３２１の伝熱管３１に対応する。 FIG. 3 is a diagram showing a ph diagram. The horizontal and vertical axes of the graph indicate specific enthalpy and pressure, respectively. The solid line schematically shows the refrigeration cycle of this embodiment. Further, T1 and T2 are a part of the isotherm. Each state in the refrigeration cycle in the figure will be described. In the figure, H1 indicates the compressor suction, H2 indicates the compressor discharge and the condenser inlet, H3 indicates the condenser outlet, H4 indicates the evaporator inlet, and H5 indicates the intermediate portion between the evaporator inlet and the evaporator outlet. The refrigerant state changes in this order to form a refrigeration cycle. Since a non-azeotropic mixed refrigerant is used as the refrigerant for heat exchange, the temperature rises when the refrigerant evaporates when the pressure is constant. However, as described above, the temperature on the inlet side of the evaporator decreases due to the predominance of pressure loss with respect to the temperature gradient of the non-azeotropic mixed refrigerant. The range of S1 in FIG. 3 is a region on the inlet side of the evaporator in which the temperature of the refrigerant gradually decreases due to this pressure loss. The range of S1 corresponds to the heat transfer tube 31 of the two-row portion 322, which becomes a parallel flow when the heat exchanger 30 operates as an evaporator. Further, the range of S2 is a region on the evaporator outlet side where the temperature gradient of the non-azeotropic mixed refrigerant becomes dominant over the pressure loss and the temperature of the refrigerant gradually rises. The range of S2 corresponds to the heat transfer tube 31 of the one row portion 321.

図４は、冷媒の流れによる、伝熱管内の冷媒の温度変化を示す図である。図４に示すグラフの横軸及び縦軸はそれぞれ、伝熱管長及び伝熱管内冷媒温度を示す。ここで、伝熱管長は、蒸発器入口からの冷媒流路の距離である。図４に示すように、２列部３２２に対応する範囲（Ｓ１）においては、圧力損失に起因して伝熱管内冷媒温度は、蒸発器入口における冷媒温度Ｔ１１から徐々に低下する。その後、非共沸混合冷媒の温度勾配が優勢になり、伝熱管内冷媒温度は低下から上昇に切り替わり、１列部３２１に対応する範囲（Ｓ２）においては、２列部３２２における最低温度Ｔ１２から蒸発器出口における冷媒温度Ｔ１３まで伝熱管内冷媒温度は徐々に上昇する。 FIG. 4 is a diagram showing a temperature change of the refrigerant in the heat transfer tube due to the flow of the refrigerant. The horizontal axis and the vertical axis of the graph shown in FIG. 4 indicate the heat transfer tube length and the refrigerant temperature in the heat transfer tube, respectively. Here, the heat transfer tube length is the distance of the refrigerant flow path from the evaporator inlet. As shown in FIG. 4, in the range (S1) corresponding to the two-row portion 322, the refrigerant temperature in the heat transfer tube gradually decreases from the refrigerant temperature T11 at the inlet of the evaporator due to the pressure loss. After that, the temperature gradient of the non-co-boiling mixed refrigerant becomes dominant, and the temperature of the refrigerant in the heat transfer tube switches from a decrease to an increase, and in the range (S2) corresponding to the first row portion 321 from the lowest temperature T12 in the second row portion 322. The temperature of the refrigerant in the heat transfer tube gradually rises up to the temperature of the refrigerant T13 at the outlet of the evaporator.

すなわち、前述の通り、１列部３２１においては、風上側から風下側に向けて空気の温度が低下するため、伝熱管内の冷媒の温度変化を空気の温度変化と同様にすることができる。これにより、熱交換効率を向上させることができる。 That is, as described above, in the one-row portion 321 the temperature of the air decreases from the windward side to the leeward side, so that the temperature change of the refrigerant in the heat transfer tube can be made the same as the temperature change of the air. This makes it possible to improve the heat exchange efficiency.

また、本実施の形態においては、図４に示すように、蒸発器出口における冷媒温度Ｔ１３が、１列部３２１と２列部３２２の切り替え点の冷媒温度Ｔ１２よりも高く、かつ空気の温度Ｔａよりも低くなるように、伝熱管３１（伝熱管３１の流路面積）が設計されているものとする。このように、１列部３２１の冷媒温度Ｔ１２よりも高くように設計されることで、１列部３２１における圧力損失を減らし、吸い込み圧力を下げ過ぎないようにすることができる。また、１列部３２１の冷媒温度を空気の温度Ｔａよりも低い温度とすることで、熱交換効率が低下するのを防ぐことができる。なお、空気の温度は、熱交換器３０により熱交換される空気の温度であり、熱交換される空気の温度は、天候等により変動する。そこで、実際には、空気調和機１が設置される地域において取り得るすべての温度条件において、空気の温度ＴａとＴ１２の温度差が、Ｔ１３とＴ１２の温度差よりも大きくなるように設計れればよい。 Further, in the present embodiment, as shown in FIG. 4, the refrigerant temperature T13 at the evaporator outlet is higher than the refrigerant temperature T12 at the switching point between the first row portion 321 and the second row portion 322, and the air temperature Ta. It is assumed that the heat transfer tube 31 (flow path area of the heat transfer tube 31) is designed so as to be lower than the above. In this way, by designing to be higher than the refrigerant temperature T12 of the first row portion 321 it is possible to reduce the pressure loss in the first row portion 321 and prevent the suction pressure from being lowered too much. Further, by setting the refrigerant temperature of the first row portion 321 to a temperature lower than the air temperature Ta, it is possible to prevent the heat exchange efficiency from deteriorating. The temperature of the air is the temperature of the air exchanged by the heat exchanger 30, and the temperature of the air exchanged with heat varies depending on the weather and the like. Therefore, in practice, if the temperature difference between the air temperatures Ta and T12 is designed to be larger than the temperature difference between T13 and T12 under all possible temperature conditions in the area where the air conditioner 1 is installed. good.

さらに、熱交換器３０は、蒸発器入口と蒸発器出口の温度が等しくなるように設計されるのが好ましい。１列部３２１と２列部３２２の伝熱管の流路面積等を設計することにより、蒸発器入口と蒸発器出口の温度を等しくすることができる。このように、蒸発器入口と蒸発器出口の温度を等しくすることにより、熱交換器３０の全体の熱交換効率を向上させることができる。 Further, the heat exchanger 30 is preferably designed so that the temperatures of the evaporator inlet and the evaporator outlet are equal to each other. By designing the flow path area and the like of the heat transfer tubes of the first row portion 321 and the second row portion 322, the temperatures of the evaporator inlet and the evaporator outlet can be made equal. By making the temperatures of the evaporator inlet and the evaporator outlet equal in this way, the heat exchange efficiency of the entire heat exchanger 30 can be improved.

また、熱交換器３０は、２列部３２２に対応した伝熱面積が、１列部３２１に対応した伝熱面積以下となるように形成される。ここで、２列部３２２の伝熱面積は、２列部３２２におけるフィン３２の表面積であり、２列部３２１の伝熱面積は、１列部３２１におけるフィン３２の表面積である。以下、この伝熱面積の関係について説明する。図５は、２列部伝熱面積の割合と、効率増加率との関係を示すグラフを示す図である。横軸は、２列部伝熱面積の割合を示し、縦軸は、効率増加率を示す。ここで、２列部伝熱面積とは、熱交換器３０の全体の伝熱面積に対する、２列部に対応した伝熱面積の割合である。また、効率増加率は、蒸発器入口側及び蒸発器出口側がいずれも対向流となる熱交換器を基準とした場合の、本実施形態に示すように蒸発器入口側が並行流となる熱交換器におけるエネルギー効率の増加率である。なお、冷媒としては、同一の非共沸混合冷媒を用いた。エネルギー効率としては、ＡＰＦ（Annual Performance Factor：通年エネルギー消費効率）の値を用いた。 Further, the heat exchanger 30 is formed so that the heat transfer area corresponding to the two-row portion 322 is equal to or less than the heat transfer area corresponding to the one-row portion 321. Here, the heat transfer area of the second row portion 322 is the surface area of the fins 32 in the second row portion 322, and the heat transfer area of the second row portion 321 is the surface area of the fins 32 in the first row portion 321. Hereinafter, the relationship between the heat transfer areas will be described. FIG. 5 is a diagram showing a graph showing the relationship between the ratio of the heat transfer area in the two rows and the efficiency increase rate. The horizontal axis shows the ratio of the heat transfer area in the two rows, and the vertical axis shows the efficiency increase rate. Here, the heat transfer area of the two rows is the ratio of the heat transfer area corresponding to the two rows to the total heat transfer area of the heat exchanger 30. Further, the efficiency increase rate is a heat exchanger in which the evaporator inlet side is a parallel flow as shown in this embodiment when the heat exchanger in which both the evaporator inlet side and the evaporator outlet side are countercurrent is used as a reference. The rate of increase in energy efficiency in. The same non-azeotropic mixed refrigerant was used as the refrigerant. As the energy efficiency, the value of APF (Annual Performance Factor) was used.

図５に示す線Ｑは、シミュレーションにより求めた、ある非共沸混合冷媒を用いた場合の効率増加率の変化を示している。同様に、温度勾配の異なる複数の非共沸混合冷媒を用いて、シミュレーション及び実験を行った。これらのシミュレーション及び実験の結果、明らかな効率増加がみられるのは、２列部伝熱面積の割合が１０％～５０％の範囲であることが分かった。さらに、効率増加率が最高値を取る範囲は、２列部伝熱面積の割合が２０％～３５％の範囲であることがわかった。 The line Q shown in FIG. 5 shows the change in the efficiency increase rate when a certain non-azeotropic mixed refrigerant is used, which is obtained by simulation. Similarly, simulations and experiments were performed using a plurality of non-azeotropic mixed refrigerants having different temperature gradients. As a result of these simulations and experiments, it was found that the ratio of the heat transfer area in the two rows was in the range of 10% to 50%, where a clear increase in efficiency was observed. Furthermore, it was found that the range in which the efficiency increase rate takes the highest value is the range in which the ratio of the heat transfer area in the two rows is 20% to 35%.

以上のことから、熱交換器３０は、２列部３２２の伝熱面積が１列部３２１の伝熱面積以下となるように形成されるのが好ましい。さらに、２列部伝熱面積の割合が１０％以上５０％以下の範囲Ｐ１となるように形成されるのが好ましい。また、熱交換器３０は、２列部伝熱面積の割合が１５％以上４０％以下の範囲Ｐ２となるように形成されるのがさらに好ましい。なお、１５％以上４０％以下の範囲は、効率増加率が最高値を取る範囲にマージンを含めた範囲である。 From the above, it is preferable that the heat exchanger 30 is formed so that the heat transfer area of the two-row portion 322 is equal to or less than the heat transfer area of the one-row portion 321. Further, it is preferable that the heat transfer area in the two rows is formed so as to be in the range P1 of 10% or more and 50% or less. Further, it is more preferable that the heat exchanger 30 is formed so that the ratio of the heat transfer area in the two rows is in the range P2 of 15% or more and 40% or less. The range of 15% or more and 40% or less is a range in which the margin is included in the range in which the efficiency increase rate takes the maximum value.

なお、フィン３２の幅方向の長さが、フィン３２の上下方向の位置によらず一定の場合には、上記伝熱面積の割合は、フィン３２の高さ方向の割合と等しくなる。ここで、幅方向とは、空気の流れる方向Ａに対応した方向である。 When the length of the fin 32 in the width direction is constant regardless of the position in the vertical direction of the fin 32, the ratio of the heat transfer area becomes equal to the ratio in the height direction of the fin 32. Here, the width direction is a direction corresponding to the air flow direction A.

さらに、１列部３２１におけるフィン３２の幅と、２列部３２２におけるフィン３２の幅とが、等しくなるように形成されるのが好ましい。ここで、フィン３２の横幅とは、空気の流れる方向Ａに沿ったフィン３２の幅（長さ）である。このように、１列部３２１におけるフィン３２の幅を２列部３２２におけるフィン３２の幅と等しくすることで、所定の高さに含まれる伝熱管３１の数が１列部３２１の方が２列部３２２に比べて少ないことによる、１列部３２１の熱交換効率の低下を補うことができる。 Further, it is preferable that the width of the fin 32 in the first row portion 321 and the width of the fin 32 in the second row portion 322 are formed to be equal to each other. Here, the width of the fin 32 is the width (length) of the fin 32 along the direction A in which the air flows. In this way, by making the width of the fins 32 in the first row portion 321 equal to the width of the fins 32 in the second row portion 322, the number of heat transfer tubes 31 included in the predetermined height is 2 in the one row portion 321. It is possible to compensate for the decrease in heat exchange efficiency of the one row portion 321 due to the fact that the number is smaller than that of the row portion 322.

なお、例えば、１列部３２１のフィン３２の幅が２列部３２２のフィン３２の幅よりも小さい場合には、１列部３２１における熱交換性能が低下する。一方で、１列部３２１のフィン３２の幅が２列部３２２のフィン３２の幅よりも大きい場合には、１列部３２１のフィン３２のうち、２列部３２２のフィン３２よりも長い部分に霜が付き、除霜できず、熱交換器３０の破損に繋がる可能性がある。したがって、１列部３２１のフィン３２と２列部３２２のフィンの幅は、両フィンの幅の差が、熱交換性能の低下や及び着霜が起こらない程度に等しければよい。 For example, when the width of the fin 32 of the first row portion 321 is smaller than the width of the fin 32 of the second row portion 322, the heat exchange performance in the first row portion 321 deteriorates. On the other hand, when the width of the fin 32 of the first row portion 321 is larger than the width of the fin 32 of the second row portion 322, the portion of the fin 32 of the first row portion 321 that is longer than the fin 32 of the second row portion 322. Is frosted and cannot be defrosted, which may lead to damage to the heat exchanger 30. Therefore, the widths of the fins 32 of the first row portion 321 and the fins of the second row portion 322 may be equal to such that the difference in width between the two fins does not cause deterioration of heat exchange performance and frost formation.

なお、２列部３２２の風上列３３１と風下列３３２とが別のユニットとして形成されている場合には、風上列３３１のフィンの幅と風下列のフィンの幅の合計値を２列部３２２のフィンの幅とし、２列部３２２のフィンの幅と１列部のフィンの幅が等しいものとする。なお、複数列の伝熱管が複数のユニットで形成されている場合には、各ユニットのフィンの幅の合計値を複数列の伝熱管におけるフィンの幅とする。 When the upwind row 331 and the downwind row 332 of the two-row portion 322 are formed as separate units, the total value of the fin width of the upwind row 331 and the fin width of the downwind row is two rows. It is assumed that the width of the fins of the portion 322 is equal to the width of the fins of the second row portion 322 and the width of the fins of the first row portion. When a plurality of rows of heat transfer tubes are formed by a plurality of units, the total value of the fin widths of each unit is taken as the fin width in the plurality of rows of heat transfer tubes.

本実施形態に係る空気調和機１において利用される非共沸混合冷媒は、熱交換時の温度勾配が２℃以上の冷媒であることが好ましい。温度勾配が２℃以上の非共沸混合冷媒を用いることで、蒸発器として動作する場合に温度勾配が圧力損失に比べて優勢になる領域においても、効率的に熱交換を行うことができる。さらに、非共沸混合冷媒は、熱交換時の温度勾配が７℃以下の冷媒であることが好ましい。温度勾配が７℃を超えると、熱交換時の冷媒温度の低下により熱交換器３０に霜が付く可能性が高くなるためである。すなわち、温度勾配が７℃以下の非共沸混合冷媒を用いることにより、霜の付着を防ぐことができる。非共沸混合冷媒としては、Ｒ３２やＲ１２５など熱交換のための性能を確保するための冷媒と、ＨＦＯ－１２３４ｙｆ、ＨＦＯ－１２３４ｚｅ（Ｅ）、ＨＦＯ-１１２３、ＨＦＯ１１３２ａ、ＨＦＯ－１１３２（Ｅ）Ｒ７４４、Ｒ２９０、Ｒ６００ａ、ＣＦ_３Ｉ（トリフルオロヨードメタン）のようにＧＷＰが比較的低い冷媒の混合冷媒が挙げられる。これらの冷媒の混合冷媒において、上記温度勾配の範囲になるように、混合割合などが調整されるものとする。 The non-azeotropic mixed refrigerant used in the air conditioner 1 according to the present embodiment is preferably a refrigerant having a temperature gradient of 2 ° C. or higher during heat exchange. By using a non-azeotropic mixed refrigerant having a temperature gradient of 2 ° C. or higher, heat exchange can be efficiently performed even in a region where the temperature gradient becomes dominant over the pressure loss when operating as an evaporator. Further, the non-azeotropic mixed refrigerant is preferably a refrigerant having a temperature gradient of 7 ° C. or less at the time of heat exchange. This is because if the temperature gradient exceeds 7 ° C., there is a high possibility that frost will form on the heat exchanger 30 due to a decrease in the refrigerant temperature during heat exchange. That is, by using a non-azeotropic mixed refrigerant having a temperature gradient of 7 ° C. or lower, adhesion of frost can be prevented. As the non-co-boiling mixed refrigerant, a refrigerant for ensuring the performance for heat exchange such as R32 and R125, and HFO-1234yf, HFO-1234ze (E), HFO-1123, HFO1132a, HFO-1132 (E) R744 , R290, R600a, CF ₃ I (trifluoroiodomethane) and other mixed refrigerants with relatively low GWP. In the mixed refrigerant of these refrigerants, the mixing ratio and the like shall be adjusted so as to be within the range of the above temperature gradient.

また、図２に示すように、室外機１０及び室内機２０が設置された状態において、熱交換器３０の蒸発器出口は、蒸発器入口よりも鉛直方向の上側に設けられている。熱交換器３０においては、フィン３２に霜が付くことがある。この場合に、熱交換器３０を凝縮器として動作させることで除霜を行う。除霜を行う場合に、凝縮入口側（蒸発器出口側）は冷媒が流れにくく、霜が溶けにくい。一方、凝縮出口側（蒸発器入口側）は流速が速く、冷媒が流れやすいため、霜が溶けやすい。本実施形態の熱交換器３０においては、蒸発器入口側の流速が蒸発器出口側の流速に比べて速いため、上記の通り、蒸発器出口側を蒸発器入口側よりも鉛直方向上側に設けられるようにした。これにより、熱交換器３０の下側において徐霜において霜が溶け切らずに残ってしまうのを防ぐことができる。さらには、熱交換器３０の下側にはドレン水を受けるためのドレンパン（不図示）やドレン水の排出口（不図示）において氷が成長し、徐霜により生じた水を排出できなくなるのを防ぐことができる。 Further, as shown in FIG. 2, in a state where the outdoor unit 10 and the indoor unit 20 are installed, the evaporator outlet of the heat exchanger 30 is provided on the upper side in the vertical direction with respect to the evaporator inlet. In the heat exchanger 30, the fins 32 may be frosted. In this case, defrosting is performed by operating the heat exchanger 30 as a condenser. When defrosting, the refrigerant does not easily flow on the condensation inlet side (evaporator outlet side), and the frost does not melt easily. On the other hand, on the condensation outlet side (evaporator inlet side), the flow velocity is high and the refrigerant easily flows, so that frost easily melts. In the heat exchanger 30 of the present embodiment, the flow velocity on the inlet side of the evaporator is faster than the flow velocity on the outlet side of the evaporator. Therefore, as described above, the outlet side of the evaporator is provided on the upper side in the vertical direction with respect to the inlet side of the evaporator. I made it possible. This makes it possible to prevent the frost from remaining unmelted in the slow frost on the lower side of the heat exchanger 30. Further, ice grows on the lower side of the heat exchanger 30 at the drain pan (not shown) for receiving the drain water and the drain water discharge port (not shown), and the water generated by the slow frost cannot be discharged. Can be prevented.

以上のように、本実施形態に係る空気調和機１の室外熱交換器１４及び室内熱交換器２１として利用される熱交換器３０においては、蒸発器入口側に１列の伝熱管が設けられ、蒸発器出口側に２列の伝熱管が設けられている。さらに、熱交換器３０は、蒸発器として動作する場合に、蒸発器入口側の冷媒の流れが並行流になるように形成され、２列部の流路面積が１列部の流路面積よりも大きくなるように形成されている。これにより、熱交換器３０は、蒸発器として動作する場合も凝縮器として動作する場合も、熱交換性能が低下するのを防ぐことができる。すなわち、熱交換のための冷媒として、非共沸混合冷媒を用いた場合の熱交換器の熱交換性能を向上させることができる。 As described above, in the heat exchanger 30 used as the outdoor heat exchanger 14 and the indoor heat exchanger 21 of the air conditioner 1 according to the present embodiment, a row of heat transfer tubes is provided on the evaporator inlet side. , Two rows of heat transfer tubes are provided on the outlet side of the evaporator. Further, the heat exchanger 30 is formed so that the flow of the refrigerant on the inlet side of the evaporator becomes a parallel flow when operating as an evaporator, and the flow path area of the two rows is larger than the flow path area of the first row. Is also formed to be large. Thereby, the heat exchanger 30 can prevent the heat exchange performance from deteriorating regardless of whether the heat exchanger operates as an evaporator or a condenser. That is, it is possible to improve the heat exchange performance of the heat exchanger when a non-azeotropic mixed refrigerant is used as the refrigerant for heat exchange.

第１の変形例としては、本実施形態においては、室外熱交換器１４及び室内熱交換器２１として熱交換器３０が用いられることとしたが、室外熱交換器１４及び室内熱交換器２１の少なくとも一方に熱交換器３０が用いられればよい。 As a first modification, in the present embodiment, the heat exchanger 30 is used as the outdoor heat exchanger 14 and the indoor heat exchanger 21, but the outdoor heat exchanger 14 and the indoor heat exchanger 21 are used. A heat exchanger 30 may be used for at least one of them.

次に第２の変形例としては、１列部３２１の伝熱管３１の流路面積が２列部３２２の流路面積よりも大きくなるように設計されていればよく、そのための具体的な構成は実施形態に限定されるものではない。例えば、１列部３２１における冷媒流路（パス）の数が２列部３２２におけるパスの数よりも多くなるように設計されてもよい。図６は、第２の変形例に係る熱交換器４０を模式的に示す図である。熱交換器４０においては、１列部３２１と２列部３２２において、内側の断面積の等しい伝熱管３１が用いられる。そして、熱交換器４０においては、１列部３２１の端部３１３から２つの冷媒経路（２パス）に分岐する。これら２つの冷媒流路のうち一方は、１列部３２１において、上側の端部３１４ａから第２冷媒出入口３１２ａまで下方向に流れ、他方は、１列部３２１において、下側の端部３１４ｂから冷媒出口３１２ｂまで上方向に流れる。このように、１列部３２１と２列部３２２において断面積の等しい伝熱管を用いた上で、１列部３２１のパスの数を増やすことで、１列部３２１の流路面積を２列部３２２の流路面積よりも大きくしてもよい。 Next, as a second modification, it is sufficient that the flow path area of the heat transfer tube 31 of the first row portion 321 is designed to be larger than the flow path area of the second row portion 322, and a specific configuration for that purpose is sufficient. Is not limited to embodiments. For example, it may be designed so that the number of refrigerant flow paths (passes) in the first row portion 321 is larger than the number of passes in the second row portion 322. FIG. 6 is a diagram schematically showing the heat exchanger 40 according to the second modification. In the heat exchanger 40, in the first row portion 321 and the second row portion 322, heat transfer tubes 31 having the same inner cross-sectional area are used. Then, in the heat exchanger 40, the end portion 313 of the one row portion 321 branches into two refrigerant paths (2 paths). One of these two refrigerant channels flows downward from the upper end 314a to the second refrigerant inlet / outlet 312a in the one-row portion 321 and the other flows downward from the lower end 314b in the one-row portion 321. It flows upward to the refrigerant outlet 312b. In this way, by using heat transfer tubes having the same cross-sectional area in the 1st row portion 321 and the 2nd row portion 322 and increasing the number of passes in the 1st row portion 321, the flow path area of the 1st row portion 321 is reduced to 2 rows. It may be larger than the flow path area of the portion 322.

なお、このように、断面積の等しい伝熱管３１を用いる場合において、１列部３２１におけるパスの数は、３以上でもよい。また、他の例としては、１列部３２１における伝熱管３１の断面積が２列部３２２における伝熱管３１の断面積よりも大きく、かつ２列部３２２におけるパスの数を１列部のパスの数よりも多い、というように、目標の圧力損失となるように伝熱管の断面積及びパスの数の両方をパラメータとして設計してもよい。 As described above, when the heat transfer tubes 31 having the same cross-sectional area are used, the number of passes in the one row portion 321 may be 3 or more. Further, as another example, the cross-sectional area of the heat transfer tube 31 in the 1-row portion 321 is larger than the cross-sectional area of the heat transfer tube 31 in the 2-row portion 322, and the number of passes in the 2-row portion 322 is the number of passes in the 1-row portion. Both the cross-sectional area of the heat transfer tube and the number of paths may be designed as parameters so as to obtain the target pressure loss, such as more than the number of.

第３の変形例としては、伝熱管の形状は、図２に示すように断面が円形となる丸管に限定されるものではない。例えば、断面が扁平な扁平管が伝熱管として用いられてもよい。また、他の例としては、内面溝付管のように、内側に溝が形成されていてもよい。図７は、扁平管を備えた熱交換器４１を示す図である。伝熱管４０１として扁平管を用いることにより、同一の高さにおいて、流路面積が扁平管と等しい丸管を用いた場合よりも、多い数の伝熱管を配列することができる。さらに、扁平管を用いることで、伝熱管からフィン４０２の風上側及び風下側の端４０２ａ，４０２ｂまでの距離を短くすることができるため、丸管に比べて熱交換効率を向上させることができる。なお、この場合、１列の扁平多孔管を２つ固定することで２列部が形成されてもよく、２列の扁平管が２列部として一体に形成されてもよい。また、１列部のユニットと２列部のユニットが上下方向に固定されることで熱交換器４１が形成されてもよく、１列部と２列部とが熱交換器４１として一体に形成されてもよい。 As a third modification, the shape of the heat transfer tube is not limited to the round tube having a circular cross section as shown in FIG. For example, a flat tube having a flat cross section may be used as a heat transfer tube. Further, as another example, a groove may be formed inside, such as an inner grooved pipe. FIG. 7 is a diagram showing a heat exchanger 41 provided with a flat tube. By using a flat tube as the heat transfer tube 401, a larger number of heat transfer tubes can be arranged at the same height than when a round tube having a flow path area equal to that of the flat tube is used. Further, by using the flat tube, the distance from the heat transfer tube to the windward and leeward ends 402a and 402b of the fin 402 can be shortened, so that the heat exchange efficiency can be improved as compared with the round tube. .. In this case, two rows of flat perforated pipes may be fixed to form a two-row portion, or two rows of flat pipes may be integrally formed as a two-row portion. Further, the heat exchanger 41 may be formed by fixing the unit of the first row portion and the unit of the second row portion in the vertical direction, and the first row portion and the second row portion are integrally formed as the heat exchanger 41. May be done.

さらに、扁平管など丸管以外の場合においては、１列部３２１の伝熱管の管幅が２列部３２２の伝熱管の管幅に比べて長くなるように伝熱管が形成されてもよい。ここで、管幅とは、空気の流れる方向Ａに沿った方向における伝熱管の幅である。図７の例では、１列部３２１の伝熱管４０１の管幅はＮ１であり、２列部３２２の伝熱管４０１の管幅はＮ２である。このように、１列部３２１の管幅が２列部３２２の管幅に比べて長くなるように伝熱管を形成することで、１列部３２１において、伝熱管４０１からフィン４０２の端４０２ａ、４０２ｂまでの距離が遠くなることによる熱交換効率の低下を防ぐことができる。 Further, in the case of a flat tube or the like other than a round tube, the heat transfer tube may be formed so that the tube width of the heat transfer tube of the first row portion 321 is longer than the tube width of the heat transfer tube of the second row portion 322. Here, the tube width is the width of the heat transfer tube in the direction along the air flow direction A. In the example of FIG. 7, the tube width of the heat transfer tube 401 of the first row portion 321 is N1, and the tube width of the heat transfer tube 401 of the second row portion 322 is N2. In this way, by forming the heat transfer tube so that the tube width of the one-row portion 321 is longer than the tube width of the two-row portion 322, the end 402a of the fins 402 from the heat transfer tube 401 in the one-row portion 321. It is possible to prevent a decrease in heat exchange efficiency due to a long distance to 402b.

さらに、扁平管を用いた熱交換器においては、目標の圧力損失に対応した流路面積になるように、伝熱管の断面積と、分岐パスの数とをパラメータとして設計されてもよい。図８に示すように、熱交換器４２において、扁平管を用い、分岐ヘッダ４２１ａ、４２１ｂを使うことで流路面積を調整することができる。扁平多孔管を使用した熱交換器４２では扁平管４２２とフィン４２３が一体に形成され、さらにこの両端に分岐ヘッダ４２１ａ、４２１ｂが配置される。そして、熱交換器４２においては、分岐ヘッダ４２１ａ、４２１ｂを用いて一度に複数本の冷媒管（扁平管）へ冷媒を分岐させることができる。このように使用する伝熱管の断面積のみではなく分岐本数の調節によっても、合計の流路面積、すなわち圧力損失が目標値になるよう設計することができる。蒸発器出口側において蒸発器入口部側に比べて分岐させる伝熱管の数を増やしていくことで伝熱管内の流速を低下させ、圧力損失を低下させることができる。また蒸発器出口側において、順次伝熱管の本数を増加させることでも同様に圧力損失を低下させることができる。 Further, in the heat exchanger using the flat tube, the cross-sectional area of the heat transfer tube and the number of branch paths may be designed as parameters so as to have a flow path area corresponding to the target pressure loss. As shown in FIG. 8, in the heat exchanger 42, the flow path area can be adjusted by using a flat tube and using the branch headers 421a and 421b. In the heat exchanger 42 using the flat perforated tube, the flat tube 422 and the fin 423 are integrally formed, and branch headers 421a and 421b are arranged at both ends thereof. Then, in the heat exchanger 42, the refrigerant can be branched to a plurality of refrigerant pipes (flat pipes) at one time by using the branch headers 421a and 421b. By adjusting not only the cross-sectional area of the heat transfer tube used in this way but also the number of branches, the total flow path area, that is, the pressure loss can be designed to be the target value. By increasing the number of heat transfer tubes to be branched on the evaporator outlet side as compared with the evaporator inlet side, the flow velocity in the heat transfer tubes can be reduced and the pressure loss can be reduced. Further, the pressure loss can be similarly reduced by sequentially increasing the number of heat transfer tubes on the outlet side of the evaporator.

第４の変形例としては、熱交換器の下側の伝熱管の列の数は複数であればよく、２列に限定されるものではない。他の例としては、熱交換器は、例えば、３列の伝熱管を備えてもよい。図９は、３列の伝熱管４３１を備えた熱交換器４３を示す図である。図９には、伝熱管が扁平管の例を示している。この場合も、冷媒流路は、蒸発器入口から風上、中央、風下の冷媒管を順に経由して、１列の伝熱管に繋がる。これにより、蒸発器入口側における冷媒の流れる方向を空気の流れに対して並行流とすることができる。 As a fourth modification, the number of rows of heat transfer tubes on the lower side of the heat exchanger may be a plurality, and is not limited to two rows. As another example, the heat exchanger may include, for example, three rows of heat transfer tubes. FIG. 9 is a diagram showing a heat exchanger 43 provided with three rows of heat transfer tubes 431. FIG. 9 shows an example in which the heat transfer tube is a flat tube. In this case as well, the refrigerant flow path is connected to a row of heat transfer pipes from the evaporator inlet via the upwind, center, and leeward refrigerant pipes in this order. As a result, the flow direction of the refrigerant on the inlet side of the evaporator can be made parallel to the air flow.

第５の変形例としては、蒸発器出口は、蒸発器入口よりも鉛直方向の上側に設けられていればよく、蒸発器出口と蒸発器入口のＸ軸方向及びＺ軸方向の位置関係は、実施形態に限定されるものではない。例えば、熱交換器３０の上部側が風上側に傾いた状態に設けられ、蒸発器出口は、蒸発器入口よりも風上側に設けられていてもよい。 As a fifth modification, the evaporator outlet may be provided above the evaporator inlet in the vertical direction, and the positional relationship between the evaporator outlet and the evaporator inlet in the X-axis direction and the Z-axis direction is determined. It is not limited to the embodiment. For example, the upper side of the heat exchanger 30 may be provided in a state of being inclined to the windward side, and the evaporator outlet may be provided on the windward side of the evaporator inlet.

第６の変形例としては、図１０に示す熱交換器４４のように、１列部３２１と２列部３２２の伝熱管の断面積は等しくてもよい。この場合も、蒸発器出口側を１列の伝熱管とすることで、凝縮器としての性能が低下するのを防ぐことができる。 As a sixth modification, as in the heat exchanger 44 shown in FIG. 10, the cross-sectional areas of the heat transfer tubes of the first row portion 321 and the second row portion 322 may be the same. Also in this case, by using a single row of heat transfer tubes on the outlet side of the evaporator, it is possible to prevent the performance of the condenser from deteriorating.

本発明は係る特定の実施形態に限定されるものではなく、例えばある実施形態の変形例を他の実施形態に適用するなど、特許請求の範囲に記載された本発明の要旨の範囲内において、種々の変形・変更が可能である。 The present invention is not limited to such a specific embodiment, and within the scope of the gist of the present invention described in the claims, for example, applying a modification of one embodiment to another embodiment. Various modifications and changes are possible.

１空気調和機
１０室外機
１１圧縮機
１２四方弁
１３アキュムレータ
１４室外熱交換器
１５室外ファン
１６室外膨張弁
２０室内機
２１室内熱交換器
２２室内ファン
２３室内膨張弁
３０、４０、４１、４２、４３、４４熱交換器
３１伝熱管
３２フィン
３１１第１冷媒出入口
３１２第２冷媒出入口 1 Air conditioner 10 Outdoor unit 11 Compressor 12 Four-way valve 13 Accumulator 14 Outdoor heat exchanger 15 Outdoor fan 16 Outdoor expansion valve 20 Indoor unit 21 Indoor heat exchanger 22 Indoor fan 23 Indoor expansion valve 30, 40, 41, 42, 43, 44 Heat exchanger 31 Heat transfer tube 32 Fin 311 1st refrigerant inlet / outlet 312 2nd refrigerant inlet / outlet

Claims

An indoor unit that uses a non-azeotropic mixed refrigerant.
Equipped with a heat exchanger that can operate as an evaporator and condenser,
In the refrigerant flow path in the heat exchanger, the flow direction of the refrigerant on the evaporator inlet side, which is the refrigerant inlet side when the heat exchanger operates as the evaporator, is parallel to the air flow. In addition, on the inlet side of the evaporator, on the outlet side of the refrigerant, which is the outlet side of the refrigerant when the heat exchanger operates as the evaporator while passing through a plurality of rows of heat transfer tubes provided in the direction of air flow. , Provided so as to pass through one row of heat transfer tubes provided above the plurality of rows of heat transfer tubes.
The evaporator outlet is an indoor unit provided above the evaporator inlet in the vertical direction.

An indoor unit that uses a non-azeotropic mixed refrigerant.
Equipped with a heat exchanger that can operate as an evaporator and condenser,
In the refrigerant flow path in the heat exchanger, the flow direction of the refrigerant on the evaporator inlet side, which is the refrigerant inlet side when the heat exchanger operates as the evaporator, is parallel to the air flow. In addition, on the inlet side of the evaporator, on the outlet side of the refrigerant, which is the outlet side of the refrigerant when the heat exchanger operates as the evaporator while passing through a plurality of rows of heat transfer tubes provided in the direction of air flow. , Provided so as to pass through one row of heat transfer tubes provided above the plurality of rows of heat transfer tubes.
The heat exchanger is an indoor unit formed so that the heat transfer area corresponding to the plurality of rows of heat transfer tubes is equal to or less than the heat transfer area corresponding to the one row of heat transfer tubes.

An outdoor unit that uses a non-azeotropic mixed refrigerant.
Equipped with a heat exchanger that can operate as an evaporator and condenser ,
In the refrigerant flow path in the heat exchanger, the flow direction of the refrigerant on the evaporator inlet side, which is the refrigerant inlet side when the heat exchanger operates as the evaporator, is parallel to the air flow. In addition, on the inlet side of the evaporator, on the outlet side of the refrigerant, which is the outlet side of the refrigerant when the heat exchanger operates as the evaporator while passing through a plurality of rows of heat transfer tubes provided in the direction of air flow. , Provided so as to pass through one row of heat transfer tubes provided above the plurality of rows of heat transfer tubes.
The evaporator outlet is an outdoor unit provided above the evaporator inlet in the vertical direction.

An outdoor unit that uses a non-azeotropic mixed refrigerant.
Equipped with a heat exchanger that can operate as an evaporator and condenser ,
In the refrigerant flow path in the heat exchanger, the flow direction of the refrigerant on the evaporator inlet side, which is the refrigerant inlet side when the heat exchanger operates as the evaporator, is parallel to the air flow. In addition, on the inlet side of the evaporator, on the outlet side of the refrigerant, which is the outlet side of the refrigerant when the heat exchanger operates as the evaporator while passing through a plurality of rows of heat transfer tubes provided in the direction of air flow. , Provided so as to pass through one row of heat transfer tubes provided above the plurality of rows of heat transfer tubes.
An outdoor unit formed so that the heat transfer area corresponding to the plurality of rows of heat transfer tubes is equal to or less than the heat transfer area corresponding to the one row of heat transfer tubes.