JP2015078799A

JP2015078799A - Air conditioner

Info

Publication number: JP2015078799A
Application number: JP2013216585A
Authority: JP
Inventors: 浩昭中宗; Hiroaki Nakamune; 洋次尾中; Yoji Onaka; 松本　崇; Takashi Matsumoto; 崇松本; 村上　泰城; Taijo Murakami; 泰城村上; 瑞朗酒井; Mizuro Sakai; 青木　正則; Masanori Aoki; 正則青木; 柴　広有; Hirokuni Shiba; 広有柴
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2013-10-17
Filing date: 2013-10-17
Publication date: 2015-04-23

Abstract

【課題】圧縮機の信頼性が損なわれることを抑制する空気調和装置を提供することを目的としている。【解決手段】圧縮機の吸入側に接続され、他方が蒸発器に接続された吸入配管と、一方が蒸発器と凝縮器とを接続する冷媒配管に接続されたレシーバと、一方がレシーバに接続され、他方が吸入配管に接続され、レシーバ内の冷媒を吸入配管に供給するバイパス配管と、吸入配管のうちバイパス配管との接続位置よりも下流側に設けられ、蒸発器側及びバイパス配管側から吸入配管に流入した冷媒とレシーバ内の冷媒とを熱交換させる熱回収部と、を備えたものである。【選択図】図１An object of the present invention is to provide an air conditioner that suppresses deterioration of the reliability of a compressor. A suction pipe connected to the suction side of the compressor and the other connected to the evaporator, a receiver connected to a refrigerant pipe connecting the evaporator and the condenser, and one connected to the receiver The other is connected to the suction pipe, and is provided on the downstream side of the connection position between the bypass pipe and the bypass pipe for supplying the refrigerant in the receiver to the suction pipe, and from the evaporator side and the bypass pipe side. And a heat recovery unit that exchanges heat between the refrigerant flowing into the suction pipe and the refrigerant in the receiver. [Selection] Figure 1

Description

本発明は、空気調和装置に関するものである。 The present invention relates to an air conditioner.

空気調和装置には、圧縮機、四方弁、凝縮器、気液分離器、膨張弁及び蒸発器を有し、気液分離器を蒸発器と膨張弁との間に配置したものが提案されている（たとえば、特許文献１参照）。特許文献１に記載の技術は、一方が気液分離器内の空間に連通するように気液分離器に接続され、他方が圧縮機の吸入側に接続されたバイパス通路を設けたものである。 As an air conditioner, a compressor, a four-way valve, a condenser, a gas-liquid separator, an expansion valve and an evaporator are proposed, and the gas-liquid separator is arranged between the evaporator and the expansion valve. (For example, see Patent Document 1). The technique described in Patent Document 1 is provided with a bypass passage in which one is connected to the gas-liquid separator so as to communicate with the space in the gas-liquid separator and the other is connected to the suction side of the compressor. .

蒸発器では外気から熱を吸収し、気液二相冷媒がガス冷媒となる。蒸発器中の冷媒に供給された二相冷媒のうちのガス冷媒は、二相冷媒のうちの液冷媒と比較すると熱交換の寄与が小さい。このため、特許文献１に記載の技術は、バイパス通路を設けることでガス冷媒と液冷媒とを分離し、蒸発器に供給されるガス冷媒量を低減させることで、蒸発器における冷媒の圧力損失を低下させ、蒸発温度を上昇させることで性能向上を図っている。 In the evaporator, heat is absorbed from outside air, and the gas-liquid two-phase refrigerant becomes a gas refrigerant. The gas refrigerant of the two-phase refrigerant supplied to the refrigerant in the evaporator has a smaller contribution to heat exchange than the liquid refrigerant of the two-phase refrigerant. For this reason, the technique described in Patent Document 1 separates the gas refrigerant and the liquid refrigerant by providing a bypass passage, and reduces the amount of gas refrigerant supplied to the evaporator, thereby reducing the pressure loss of the refrigerant in the evaporator. The performance is improved by lowering the temperature and raising the evaporation temperature.

特開２００３−２５４６３２号公報（たとえば、図２参照）JP 2003-254632 A (see, for example, FIG. 2)

特許文献１に記載の技術は、気液分離器及びバイパス通路により、二相冷媒中のガス冷媒を分離し、圧縮機の吸入側に戻すことで、蒸発器の圧力損失の増加を抑制している。ここで、外気温度、室内負荷の急激な変化などが生じた場合には、一時的に気液分離器内に貯留する液冷媒が増加したり、あるいは気液分離器に流入する二相冷媒の流量が増加したりすることがある。このような場合には、バイパス通路に液冷媒が流入し、バイパス通路と連通する圧縮機の吸入側に液冷媒が流入してしまう場合がある（液バック）。液バックが生じると、圧縮機の信頼性を損なう可能性がある。すなわち、特許文献１に記載の技術では、液バックにより、圧縮機の信頼性を損なう可能性があるという課題がある。 The technique described in Patent Document 1 suppresses an increase in the pressure loss of the evaporator by separating the gas refrigerant in the two-phase refrigerant by the gas-liquid separator and the bypass passage and returning it to the suction side of the compressor. Yes. Here, when a sudden change occurs in the outside air temperature or the indoor load, the liquid refrigerant temporarily stored in the gas-liquid separator increases or the two-phase refrigerant flowing into the gas-liquid separator The flow rate may increase. In such a case, the liquid refrigerant may flow into the bypass passage, and the liquid refrigerant may flow into the suction side of the compressor communicating with the bypass passage (liquid back). If liquid back occurs, the reliability of the compressor may be impaired. In other words, the technique described in Patent Document 1 has a problem that the liquid back may impair the reliability of the compressor.

本発明は、以上のような課題を解決するためになされたもので、圧縮機の信頼性が損なわれることを抑制する空気調和装置を提供することを目的としている。 The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an air conditioner that suppresses the deterioration of the reliability of the compressor.

本発明に係る空気調和装置は、圧縮機、凝縮器、膨張弁、及び蒸発器を冷媒配管で接続して構成された冷凍サイクルを有する空気調和装置において、一方が圧縮機の吸入側に接続され、他方が蒸発器に接続された吸入配管と、蒸発器と凝縮器とを接続する冷媒配管に接続されたレシーバと、一方がレシーバに接続され、他方が吸入配管に接続され、レシーバ内の冷媒を吸入配管に供給するバイパス配管と、吸入配管のうちバイパス配管との接続位置よりも下流側に設けられ、蒸発器側及びバイパス配管側から吸入配管に流入した冷媒とレシーバ内の冷媒とを熱交換させる熱回収部と、を備えたものである。 An air conditioner according to the present invention is an air conditioner having a refrigeration cycle configured by connecting a compressor, a condenser, an expansion valve, and an evaporator with a refrigerant pipe, one of which is connected to the suction side of the compressor. A suction pipe connected to the evaporator on the other side, a receiver connected to a refrigerant pipe connecting the evaporator and the condenser, one connected to the receiver, the other connected to the suction pipe, and a refrigerant in the receiver Is provided downstream of the connection position between the bypass pipe and the bypass pipe, and the refrigerant flowing into the suction pipe from the evaporator side and the bypass pipe side and the refrigerant in the receiver are heated. And a heat recovery unit to be exchanged.

本発明に係る空気調和装置によれば、上記構成を有しているため、圧縮機の信頼性が損なわれることを抑制することができる。 Since the air conditioner according to the present invention has the above-described configuration, it is possible to prevent the reliability of the compressor from being impaired.

本発明の実施の形態１に係る空気調和装置の冷媒回路構成の一例である。It is an example of the refrigerant circuit structure of the air conditioning apparatus which concerns on Embodiment 1 of this invention. 本発明の実施の形態２に係る空気調和装置の冷媒回路構成の一例である。It is an example of the refrigerant circuit structure of the air conditioning apparatus which concerns on Embodiment 2 of this invention. 本発明の実施の形態３に係る空気調和装置の冷媒回路構成の一例である。It is an example of the refrigerant circuit structure of the air conditioning apparatus which concerns on Embodiment 3 of this invention. 本発明の実施の形態４に係る空気調和装置の冷媒回路構成の一例である。It is an example of the refrigerant circuit structure of the air conditioning apparatus which concerns on Embodiment 4 of this invention.

以下、本発明の実施の形態を図面に基づいて説明する。
実施の形態１．
図１は、実施の形態１に係る空気調和装置３００の冷媒回路構成の一例である。
本実施の形態１に係る空気調和装置３００は、圧縮機１の信頼性が損なわれることを抑制することができる改良が加えられたものである。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is an example of a refrigerant circuit configuration of an air-conditioning apparatus 300 according to Embodiment 1.
The air conditioning apparatus 300 according to the first embodiment is provided with an improvement that can suppress the deterioration of the reliability of the compressor 1.

［構成説明］
空気調和装置３００は、たとえば屋外などに設置される室外ユニット１００と、たとえば空調対象空間、天井裏などに設置される室内ユニット２００とを有するものである。そして、空気調和装置３００は、圧縮機１、四方弁２、室内熱交換器３、第１膨張弁４、レシーバ５、第２膨張弁６、室外熱交換器７、及び流量制御弁１１などが、吸入配管８、バイパス配管１０及び冷媒配管５０Ａ〜５０Ｄなどで接続されて構成された冷媒回路を有している。また、空気調和装置３００は、四方弁２の接続の切り換えなどを行う制御手段２０を有している。 [Description of configuration]
The air conditioner 300 includes an outdoor unit 100 that is installed, for example, outdoors, and an indoor unit 200 that is installed, for example, in a space to be air-conditioned or on the ceiling. The air conditioner 300 includes a compressor 1, a four-way valve 2, an indoor heat exchanger 3, a first expansion valve 4, a receiver 5, a second expansion valve 6, an outdoor heat exchanger 7, a flow control valve 11, and the like. The refrigerant circuit is configured to be connected by the suction pipe 8, the bypass pipe 10, the refrigerant pipes 50A to 50D, and the like. In addition, the air conditioner 300 includes a control unit 20 that switches connection of the four-way valve 2 and the like.

（室外ユニット１００）
室外ユニット１００は、圧縮機１、四方弁２、第１膨張弁４、レシーバ５、第２膨張弁６、室外熱交換器７、及び流量制御弁１１が搭載されているものである。室外ユニット１００は、冷媒配管５０Ａ及び冷媒配管５０Ｂを介して室内ユニット２００に接続されている。また、室外ユニット１００には、室外熱交換器７に空気を供給し、当該供給した空気と室外熱交換器７を流れる冷媒とを熱交換させる送風手段（図示省略）が搭載されている。なお、送風手段としては、たとえば、送風機を用いることができる。 (Outdoor unit 100)
The outdoor unit 100 includes a compressor 1, a four-way valve 2, a first expansion valve 4, a receiver 5, a second expansion valve 6, an outdoor heat exchanger 7, and a flow control valve 11. The outdoor unit 100 is connected to the indoor unit 200 via the refrigerant pipe 50A and the refrigerant pipe 50B. In addition, the outdoor unit 100 is equipped with air blowing means (not shown) for supplying air to the outdoor heat exchanger 7 and exchanging heat between the supplied air and the refrigerant flowing through the outdoor heat exchanger 7. In addition, as a ventilation means, a blower can be used, for example.

（室内ユニット２００）
室内ユニット２００は、室内熱交換器３が搭載されているものである。室内ユニット２００は、冷媒配管５０Ａ及び冷媒配管５０Ｂを介して室外ユニット１００に接続されている。また、室内ユニット２００には、室内熱交換器３に空気を供給し、当該供給した空気と室内熱交換器３を流れる冷媒とを熱交換させ、空調対象空間（たとえば、部屋、ビルの一室、倉庫など）に供給する送風機（図示省略）が搭載されている。 (Indoor unit 200)
The indoor unit 200 is mounted with the indoor heat exchanger 3. The indoor unit 200 is connected to the outdoor unit 100 via the refrigerant pipe 50A and the refrigerant pipe 50B. Further, the indoor unit 200 supplies air to the indoor heat exchanger 3 and exchanges heat between the supplied air and the refrigerant flowing through the indoor heat exchanger 3, so that an air-conditioning target space (for example, a room, a room of a building) A blower (not shown) for supplying to a warehouse or the like is mounted.

（圧縮機１）
圧縮機１は、冷媒を吸入し、その冷媒を圧縮して高温・高圧の状態にして吐出するものである。圧縮機１は、冷媒吐出側が四方弁２に接続され、冷媒吸入側がレシーバ５に接続されている。なお、圧縮機１は、たとえばインバーター圧縮機などで構成するとよい。 (Compressor 1)
The compressor 1 sucks a refrigerant, compresses the refrigerant, and discharges the refrigerant in a high temperature / high pressure state. The compressor 1 has a refrigerant discharge side connected to the four-way valve 2 and a refrigerant suction side connected to the receiver 5. In addition, the compressor 1 is good to comprise, for example with an inverter compressor.

（四方弁２）
四方弁２は、冷媒の流路を切り換えるのに利用されるものである。四方弁２は、暖房運転時には、圧縮機１の吐出側と室内熱交換器３とを接続するとともに、圧縮機１の吸入側と室外熱交換器７とを接続するものである。四方弁２は、冷房運転時には、圧縮機１の吐出側と室外熱交換器７とを接続するとともに、圧縮機１の吸入側と室内熱交換器３とを接続するものである。なお、四方弁２の代わりに、複数の２方弁などを組み合わせて四方弁２と同様の機能を持たせたものを用いてもよい。 (Four-way valve 2)
The four-way valve 2 is used to switch the refrigerant flow path. The four-way valve 2 connects the discharge side of the compressor 1 and the indoor heat exchanger 3 and connects the suction side of the compressor 1 and the outdoor heat exchanger 7 during heating operation. The four-way valve 2 connects the discharge side of the compressor 1 and the outdoor heat exchanger 7 and also connects the suction side of the compressor 1 and the indoor heat exchanger 3 during the cooling operation. Instead of the four-way valve 2, a combination of a plurality of two-way valves and the like having the same function as the four-way valve 2 may be used.

（室内熱交換器３）
室内熱交換器３は、暖房運転時には凝縮器（放熱器）として機能し、圧縮機１から吐出された冷媒と空気との間で熱交換を行わせるものである。また、室内熱交換器３は、冷房運転時には蒸発器として機能し、第１膨張弁４から流出した冷媒と空気との間で熱交換を行わせるものである。室内熱交換器３は、一方が冷媒配管５０Ａを介して四方弁２に接続され、他方が冷媒配管５０Ｂを介して第１膨張弁４に接続されている。なお、室内熱交換器３は、たとえば、室内熱交換器３を流れる冷媒とフィンを通過する空気との間で熱交換ができるようなプレートフィンアンドチューブ型熱交換器で構成するとよい。 (Indoor heat exchanger 3)
The indoor heat exchanger 3 functions as a condenser (heat radiator) during heating operation, and performs heat exchange between the refrigerant discharged from the compressor 1 and air. The indoor heat exchanger 3 functions as an evaporator during the cooling operation, and exchanges heat between the refrigerant flowing out of the first expansion valve 4 and the air. One of the indoor heat exchangers 3 is connected to the four-way valve 2 via the refrigerant pipe 50A, and the other is connected to the first expansion valve 4 via the refrigerant pipe 50B. In addition, the indoor heat exchanger 3 is good to comprise for example a plate fin and tube type heat exchanger which can exchange heat between the refrigerant | coolant which flows through the indoor heat exchanger 3, and the air which passes a fin.

（第１膨張弁４及び第２膨張弁６）
第１膨張弁４及び第２膨張弁６は、冷媒を膨張させるのに利用されるものである。第１膨張弁４は、一方が室内熱交換器３に接続され、他方がレシーバ５に接続されているものである。また、第２膨張弁６は、一方がレシーバ５に接続され、他方が室外熱交換器７に接続されているものである。 (First expansion valve 4 and second expansion valve 6)
The first expansion valve 4 and the second expansion valve 6 are used for expanding the refrigerant. One of the first expansion valves 4 is connected to the indoor heat exchanger 3 and the other is connected to the receiver 5. Further, one of the second expansion valves 6 is connected to the receiver 5 and the other is connected to the outdoor heat exchanger 7.

（レシーバ５）
レシーバ５（気液分離器）は、液冷媒を貯留するのに利用されるものであり、液側が冷媒配管５０Ｂを介して第１膨張弁４に接続されるとともに、冷媒配管５０Ｃを介して第２膨張弁６に接続されている。また、レシーバ５は、ガス側がバイパス配管１０を介して流量制御弁１１にも接続されている。なお、レシーバ５は、図１に示すように、レシーバ５の上部にバイパス配管１０が接続されている。そして、バイパス配管１０のレシーバ５内に配置された端部は、たとえばレシーバ５内に貯留される液冷媒の液面よりも上側にくるように配置される。 (Receiver 5)
The receiver 5 (gas-liquid separator) is used to store the liquid refrigerant, and the liquid side is connected to the first expansion valve 4 via the refrigerant pipe 50B and is connected to the first via the refrigerant pipe 50C. 2 connected to the expansion valve 6. The receiver 5 is also connected to the flow control valve 11 on the gas side via the bypass pipe 10. The receiver 5 has a bypass pipe 10 connected to the upper part of the receiver 5 as shown in FIG. And the edge part arrange | positioned in the receiver 5 of the bypass piping 10 is arrange | positioned so that it may come above the liquid level of the liquid refrigerant stored in the receiver 5, for example.

さらに、レシーバ５は、吸入配管８がレシーバ５内を通るように接続されている。この吸入配管８のうちレシーバ５内に設けられている部分は、レシーバ５内の冷媒が有する熱を吸入配管８を流れる冷媒に伝達させて熱を回収する熱回収部９である。レシーバ５内には、この熱回収部９が設けられている。 Further, the receiver 5 is connected so that the suction pipe 8 passes through the receiver 5. A portion of the suction pipe 8 provided in the receiver 5 is a heat recovery unit 9 that recovers heat by transmitting heat of the refrigerant in the receiver 5 to the refrigerant flowing through the suction pipe 8. The heat recovery unit 9 is provided in the receiver 5.

（室外熱交換器７）
室外熱交換器７は、暖房運転時には蒸発器として機能し、第２膨張弁６から流出した冷媒と空気との間で熱交換を行わせるものである。また、室外熱交換器７は、冷房運転時には凝縮器として機能し、圧縮機１から吐出した冷媒と空気との間で熱交換を行わせるものである。室外熱交換器７は、一方が冷媒配管５０Ｃを介して第２膨張弁６に接続され、他方が冷媒配管５０Ｄを介して四方弁２に接続されている。なお、室外熱交換器７は、室内熱交換器３と同様に、たとえば、室内熱交換器３を流れる冷媒とフィンを通過する空気との間で熱交換ができるようなプレートフィンアンドチューブ型熱交換器で構成するとよい。 (Outdoor heat exchanger 7)
The outdoor heat exchanger 7 functions as an evaporator during heating operation, and exchanges heat between the refrigerant flowing out of the second expansion valve 6 and the air. The outdoor heat exchanger 7 functions as a condenser during the cooling operation, and exchanges heat between the refrigerant discharged from the compressor 1 and the air. One of the outdoor heat exchangers 7 is connected to the second expansion valve 6 via the refrigerant pipe 50C, and the other is connected to the four-way valve 2 via the refrigerant pipe 50D. The outdoor heat exchanger 7 is, for example, a plate fin and tube type heat that can exchange heat between the refrigerant flowing through the indoor heat exchanger 3 and the air passing through the fins, like the indoor heat exchanger 3. It may be configured with an exchanger.

（吸入配管８）
吸入配管８は、一方が四方弁２に接続され、他方が圧縮機１の吸入側に接続されているものである。また、吸入配管８は、その一部がレシーバ５内に配置されている。すなわち、吸入配管８は、レシーバ５の内部に延出した後に、レシーバ５の外側に延出し、圧縮機１の吸入側に接続されている。 (Suction pipe 8)
One of the suction pipes 8 is connected to the four-way valve 2 and the other is connected to the suction side of the compressor 1. A part of the suction pipe 8 is disposed in the receiver 5. That is, the suction pipe 8 extends to the inside of the receiver 5, then extends to the outside of the receiver 5, and is connected to the suction side of the compressor 1.

（熱回収部９）
吸入配管８のうちのレシーバ５内の部分が、熱回収部９である。なお、図１の例では、熱回収部９の形状は、レシーバ５内にて上側から下側に延出した後に、レシーバ５内にて水平方向に延出し、さらに、レシーバ５内にて下側から上側に延出するような形状を図示しているがそれに限定されるものではない。熱回収部９は、たとえば、レシーバ５内にて螺旋状に曲げられた形状を有していてもよい。これにより、レシーバ５内の冷媒と熱回収部９内の冷媒との熱交換量を大きくすることができる。また、熱回収部９は、たとえば、レシーバ５の底部側まで延出するように形成されていてもよい。これにより、熱回収部９が液冷媒に浸漬され、レシーバ５内の冷媒と熱回収部９内の冷媒との熱交換量を増大させることができる。 (Heat recovery unit 9)
A portion of the suction pipe 8 in the receiver 5 is a heat recovery unit 9. In the example of FIG. 1, the shape of the heat recovery unit 9 extends from the upper side to the lower side in the receiver 5, then extends in the horizontal direction in the receiver 5, and further in the receiver 5. Although a shape extending from the side to the upper side is illustrated, the shape is not limited thereto. The heat recovery unit 9 may have, for example, a shape bent spirally in the receiver 5. Thereby, the amount of heat exchange between the refrigerant in the receiver 5 and the refrigerant in the heat recovery unit 9 can be increased. Moreover, the heat recovery unit 9 may be formed to extend to the bottom side of the receiver 5, for example. Thereby, the heat recovery unit 9 is immersed in the liquid refrigerant, and the amount of heat exchange between the refrigerant in the receiver 5 and the refrigerant in the heat recovery unit 9 can be increased.

（バイパス配管１０）
バイパス配管１０は、一方がレシーバ５に接続され、バイパス配管１０の端部の開口がレシーバ５内に位置している。バイパス配管１０は、他方が吸入配管８に接続されている。なお、バイパス配管１０には、流量制御弁１１が接続されている。なお、バイパス配管１０と吸入配管８との接続位置は、吸入配管８のうちレシーバ５の内部に入るよりも上流側である。 (Bypass piping 10)
One of the bypass pipes 10 is connected to the receiver 5, and the opening at the end of the bypass pipe 10 is located in the receiver 5. The other side of the bypass pipe 10 is connected to the suction pipe 8. The bypass pipe 10 is connected with a flow control valve 11. Note that the connection position between the bypass pipe 10 and the suction pipe 8 is upstream of the suction pipe 8 from the inside of the receiver 5.

（流量制御弁１１）
流量制御弁１１は、バイパス配管１０に設けられ、バイパス配管１０を流れる冷媒量を調整するのに利用されるものである。流量制御弁１１は、一方がレシーバ５内の空間と連通し、他方が吸入配管８に接続されている。なお、上記の第１膨張弁４及び第２膨張弁６とともに、流量制御弁１１は、たとえば開度が可変である電子膨張弁などで構成するとよいが、バイパス流量を固定とする場合は、電磁弁やキャピラリーチューブを用いてもよい。 (Flow control valve 11)
The flow control valve 11 is provided in the bypass pipe 10 and is used to adjust the amount of refrigerant flowing through the bypass pipe 10. One of the flow control valves 11 communicates with the space in the receiver 5, and the other is connected to the suction pipe 8. In addition to the first expansion valve 4 and the second expansion valve 6 described above, the flow control valve 11 may be composed of an electronic expansion valve having a variable opening, for example. A valve or a capillary tube may be used.

（冷媒配管５０Ａ〜冷媒配管５０Ｄ）
冷媒配管５０Ａは、四方弁２と室内熱交換器３とを接続する配管である。また、室外ユニット１００と室内ユニット２００とを接続する配管でもある。冷媒配管５０Ｂは、室内熱交換器３とレシーバ５とを接続する配管である。また、冷媒配管５０Ｂには、途中に第１膨張弁４が接続されている。また、冷媒配管５０Ｂは、室外ユニット１００と室内ユニット２００とを接続する配管でもある。冷媒配管５０Ｃは、レシーバ５と室外熱交換器７とを接続する配管である。また、冷媒配管５０Ｃには、途中に第２膨張弁６が接続されている。冷媒配管５０Ｃは室外ユニット１００に設けられている。冷媒配管５０Ｄは、室外熱交換器７と四方弁２とを接続する配管である。冷媒配管５０Ｄは室外ユニット１００に設けられている。 (Refrigerant piping 50A to refrigerant piping 50D)
The refrigerant pipe 50 </ b> A is a pipe that connects the four-way valve 2 and the indoor heat exchanger 3. Further, it is a pipe connecting the outdoor unit 100 and the indoor unit 200. The refrigerant pipe 50 </ b> B is a pipe that connects the indoor heat exchanger 3 and the receiver 5. Moreover, the 1st expansion valve 4 is connected to the refrigerant | coolant piping 50B on the way. The refrigerant pipe 50B is also a pipe that connects the outdoor unit 100 and the indoor unit 200. The refrigerant pipe 50 </ b> C is a pipe that connects the receiver 5 and the outdoor heat exchanger 7. The second expansion valve 6 is connected to the refrigerant pipe 50C in the middle. The refrigerant pipe 50 </ b> C is provided in the outdoor unit 100. The refrigerant pipe 50D is a pipe that connects the outdoor heat exchanger 7 and the four-way valve 2. The refrigerant pipe 50D is provided in the outdoor unit 100.

（制御手段２０）
制御手段２０は、圧縮機１の回転数（運転／停止含む）、室内熱交換器３及び室外熱交換器７に付設される図示省略の送風手段の回転数（運転／停止含む）、第１膨張弁４、第２膨張弁６及び流量制御弁１１の開度などを制御するものである。制御手段２０は、たとえば、マイコンなどで構成される制御装置である。図１では、制御手段２０が室外ユニット１００及び室内ユニット２００の外側に搭載された場合を例に示しているが、それに限定されるものではなく、たとえば、室外ユニット１００及び室内ユニット２００のいずれか一方に搭載されていてもよい。 (Control means 20)
The control means 20 includes the rotation speed (including operation / stop) of the compressor 1, the rotation speed (including operation / stop) of a blower means (not shown) attached to the indoor heat exchanger 3 and the outdoor heat exchanger 7, The opening degree of the expansion valve 4, the second expansion valve 6, and the flow rate control valve 11 is controlled. The control means 20 is a control device composed of, for example, a microcomputer. In FIG. 1, the case where the control means 20 is mounted outside the outdoor unit 100 and the indoor unit 200 is shown as an example. However, the present invention is not limited to this. For example, any one of the outdoor unit 100 and the indoor unit 200 is used. It may be mounted on one side.

［動作説明］
凝縮器は、冷房運転時においては室外熱交換器７であり、暖房運転時においては室内熱交換器３である。蒸発器は、冷房運転時においては室内熱交換器３であり、暖房運転時においては室外熱交換器７である。このような構成を有する空気調和装置３００の動作について次に説明する。 [Description of operation]
The condenser is the outdoor heat exchanger 7 during the cooling operation, and the indoor heat exchanger 3 during the heating operation. The evaporator is the indoor heat exchanger 3 during the cooling operation, and the outdoor heat exchanger 7 during the heating operation. Next, the operation of the air conditioning apparatus 300 having such a configuration will be described.

（暖房動作の場合）
圧縮機１で高温高圧に圧縮された冷媒ガスは四方弁２の実線に沿って室内熱交換器３に流入し、図示しないファンなどの送風手段によって、室内空気との熱交換がなされて室内に熱を放出し、高温高圧の液冷媒に凝縮する。高温高圧の液冷媒は、第１膨張弁４により減圧されて中間圧力の二相冷媒となり、レシーバ５に貯留される。レシーバ５に貯留された二相冷媒は、熱回収部９の一部を構成する吸入配管８を流れる低温のガス冷媒と熱交換し、液冷媒は中間圧力となる。なお、レシーバ５に貯留された二相冷媒と比較すると、吸入配管８にて低温のガス冷媒が流れるのは、吸入配管８を流れる冷媒が蒸発器として機能する室外熱交換器７を通過しているためである。 (In case of heating operation)
The refrigerant gas compressed to high temperature and high pressure by the compressor 1 flows into the indoor heat exchanger 3 along the solid line of the four-way valve 2, and heat is exchanged with room air by a blowing means such as a fan (not shown). Releases heat and condenses into high-temperature and high-pressure liquid refrigerant. The high-temperature and high-pressure liquid refrigerant is depressurized by the first expansion valve 4 to become an intermediate-pressure two-phase refrigerant and stored in the receiver 5. The two-phase refrigerant stored in the receiver 5 exchanges heat with the low-temperature gas refrigerant flowing through the suction pipe 8 constituting a part of the heat recovery unit 9, and the liquid refrigerant becomes an intermediate pressure. Compared with the two-phase refrigerant stored in the receiver 5, the low-temperature gas refrigerant flows in the suction pipe 8 through the outdoor heat exchanger 7 in which the refrigerant flowing in the suction pipe 8 functions as an evaporator. Because it is.

レシーバ５から流出した液冷媒は、第２膨張弁６により減圧されて低温低圧の二相冷媒になる。二相冷媒は室外熱交換器７に流入し、図示しないファンなどの送風手段によって、室外空気との熱交換がなされて外気の熱を吸収し、低温低圧のガス冷媒に蒸発する。
室外熱交換器７から流出した低温低圧のガス冷媒は、四方弁２を介して吸入配管８に流入し、その後、バイパス配管１０を流れる冷媒と合流する。この合流した冷媒は、レシーバ５内の熱回収部９に流入し、レシーバ５内の冷媒と熱交換をする。これにより、合流した冷媒に液冷媒が存在している場合には、その液冷媒のガス化が促される。熱回収部９から流出した冷媒は、圧縮機１の吸入側から吸引される。 The liquid refrigerant flowing out from the receiver 5 is decompressed by the second expansion valve 6 and becomes a low-temperature and low-pressure two-phase refrigerant. The two-phase refrigerant flows into the outdoor heat exchanger 7, heat exchange with the outdoor air is performed by a blowing means such as a fan (not shown), absorbs the heat of the outdoor air, and evaporates into a low-temperature and low-pressure gas refrigerant.
The low-temperature and low-pressure gas refrigerant that has flowed out of the outdoor heat exchanger 7 flows into the suction pipe 8 via the four-way valve 2, and then merges with the refrigerant that flows through the bypass pipe 10. The merged refrigerant flows into the heat recovery unit 9 in the receiver 5 and exchanges heat with the refrigerant in the receiver 5. Thereby, when the liquid refrigerant exists in the merged refrigerant, gasification of the liquid refrigerant is promoted. The refrigerant flowing out from the heat recovery unit 9 is sucked from the suction side of the compressor 1.

（実施の形態１に係る空気調和装置３００の有する効果：暖房動作の場合）
本実施の形態１に係る空気調和装置３００ではレシーバ５内のガス冷媒を圧縮機１の吸入側にバイパスするバイパス配管１０を設け、室外熱交換器７で蒸発に寄与しないガス冷媒をバイパスさせるので蒸発器での冷媒圧力損失を低減でき、蒸発圧力を上昇させることができる。これにより、圧縮機１の電気入力を低減でき、その結果、空気調和装置３００の省エネ性を向上させることができる。なお、ガス冷媒をバイパスさせる量は、制御手段２０が流量制御弁１１の開度を制御することで調節される。 (Effects of the air-conditioning apparatus 300 according to Embodiment 1: heating operation)
In the air conditioner 300 according to the first embodiment, the bypass refrigerant 10 that bypasses the gas refrigerant in the receiver 5 on the suction side of the compressor 1 is provided, and the gas refrigerant that does not contribute to evaporation is bypassed by the outdoor heat exchanger 7. The refrigerant pressure loss in the evaporator can be reduced, and the evaporation pressure can be increased. Thereby, the electrical input of the compressor 1 can be reduced, As a result, the energy-saving property of the air conditioning apparatus 300 can be improved. The amount of bypassing the gas refrigerant is adjusted by the control means 20 controlling the opening degree of the flow control valve 11.

外気温度、室内負荷などの急激な変化などが生じた場合には、レシーバ５内に貯留される二相冷媒の一時的な増加、あるいはレシーバ５に流入する二相冷媒の流量の増加などが生じ、バイパス配管１０に液冷媒が流入する場合がある。仮に、液冷媒が、圧縮機１の吸入側に連通するバイパス配管１０に流入してしまう液バックが生じると、圧縮機１の信頼性を損なう可能性がある。 When a sudden change such as the outside air temperature or the indoor load occurs, the two-phase refrigerant stored in the receiver 5 temporarily increases or the flow rate of the two-phase refrigerant flowing into the receiver 5 increases. The liquid refrigerant may flow into the bypass pipe 10. If a liquid back in which the liquid refrigerant flows into the bypass pipe 10 communicating with the suction side of the compressor 1 occurs, the reliability of the compressor 1 may be impaired.

しかし、本実施の形態１に係る空気調和装置３００は、熱回収部９を有するとともに、バイパス配管１０の他方を、吸入配管８のうち四方弁２と熱回収部９との間に接続したものである。このため、バイパス配管１０に液冷媒が流入しても、この流入した液冷媒は、バイパス配管１０の下流側に位置する熱回収部９に流れ込む。この熱回収部９に流れ込んだ液冷媒は、レシーバ５に貯留される冷媒から熱を受け取って蒸発ガス化する。このため、本実施の形態１に係る空気調和装置３００は、バイパス配管１０に液冷媒が流入してしまっても、圧縮機１の吸入側に液冷媒が流れ込むことが抑制され、圧縮機１の信頼性を損なうことが抑制される。すなわち、本実施の形態１に係る空気調和装置３００は、圧縮機１の信頼性を確保することができる。 However, the air-conditioning apparatus 300 according to Embodiment 1 has the heat recovery unit 9 and the other of the bypass pipes 10 connected between the four-way valve 2 and the heat recovery unit 9 in the suction pipe 8. It is. For this reason, even if the liquid refrigerant flows into the bypass pipe 10, the liquid refrigerant that has flowed in flows into the heat recovery unit 9 located on the downstream side of the bypass pipe 10. The liquid refrigerant that has flowed into the heat recovery unit 9 receives heat from the refrigerant stored in the receiver 5 and evaporates. For this reason, the air-conditioning apparatus 300 according to the first embodiment suppresses the liquid refrigerant from flowing into the suction side of the compressor 1 even when the liquid refrigerant flows into the bypass pipe 10. Impairing reliability is suppressed. That is, the air conditioning apparatus 300 according to Embodiment 1 can ensure the reliability of the compressor 1.

（冷房動作の場合）
圧縮機１で高温高圧に圧縮された冷媒ガスは、四方弁２の破線に沿って室外熱交換器７に流入し、図示しないファンなどの送風手段によって、室外空気との熱交換がなされて室外に熱を放出し、高温高圧の液冷媒に凝縮する。高温高圧の液冷媒は、第２膨張弁６により減圧されて中間圧力の二相冷媒となり、レシーバ５に貯留される。
レシーバ５に貯留された二相冷媒は、熱回収部９により低温のガス冷媒と熱交換し、液冷媒は、中間圧力の液冷媒となる。なお、レシーバ５に貯留された二相冷媒と比較すると、吸入配管８にて低温のガス冷媒が流れるのは、吸入配管８を流れる冷媒が蒸発器として機能する室内熱交換器３を通過しているためである。 (Cooling operation)
The refrigerant gas compressed to high temperature and high pressure by the compressor 1 flows into the outdoor heat exchanger 7 along the broken line of the four-way valve 2, and heat exchange with the outdoor air is performed by a blowing means such as a fan (not shown). The heat is discharged into the liquid and condensed into a high-temperature and high-pressure liquid refrigerant. The high-temperature and high-pressure liquid refrigerant is decompressed by the second expansion valve 6 to become a two-phase refrigerant having an intermediate pressure, and is stored in the receiver 5.
The two-phase refrigerant stored in the receiver 5 exchanges heat with a low-temperature gas refrigerant by the heat recovery unit 9, and the liquid refrigerant becomes a liquid refrigerant at an intermediate pressure. Compared with the two-phase refrigerant stored in the receiver 5, the low-temperature gas refrigerant flows through the suction pipe 8 because the refrigerant flowing through the suction pipe 8 passes through the indoor heat exchanger 3 functioning as an evaporator. Because it is.

レシーバ５から流出した液冷媒は、第１膨張弁４により減圧されて低温低圧の二相冷媒になる。二相冷媒は室内熱交換器３に流入し、図示しないファンなどの送風手段によって、室内空気との熱交換がなされて室内の熱を吸収し、低温低圧のガス冷媒に蒸発する。
室内熱交換器３から流出した低温低圧のガス冷媒は、四方弁２を介して吸入配管８に流入し、その後、バイパス配管１０を流れる冷媒と合流する。この合流した冷媒は、レシーバ５内の熱回収部９に流入し、レシーバ５内の冷媒と熱交換をする。これにより、合流した冷媒に液冷媒が存在している場合には、その液冷媒のガス化が促される。熱回収部９から流出した冷媒は、圧縮機１の吸入側から吸引される。 The liquid refrigerant flowing out from the receiver 5 is decompressed by the first expansion valve 4 and becomes a low-temperature and low-pressure two-phase refrigerant. The two-phase refrigerant flows into the indoor heat exchanger 3, and heat exchange with room air is performed by a blowing means such as a fan (not shown) to absorb room heat and evaporate into a low-temperature and low-pressure gas refrigerant.
The low-temperature and low-pressure gas refrigerant that has flowed out of the indoor heat exchanger 3 flows into the suction pipe 8 through the four-way valve 2, and then merges with the refrigerant that flows through the bypass pipe 10. The merged refrigerant flows into the heat recovery unit 9 in the receiver 5 and exchanges heat with the refrigerant in the receiver 5. Thereby, when the liquid refrigerant exists in the merged refrigerant, gasification of the liquid refrigerant is promoted. The refrigerant flowing out from the heat recovery unit 9 is sucked from the suction side of the compressor 1.

（実施の形態１に係る空気調和装置３００の有する効果：冷房動作の場合）
本実施の形態１に係る空気調和装置３００では、レシーバ５内のガス冷媒を圧縮機１の吸入側にバイパスするバイパス配管１０を設け、室内熱交換器３で蒸発に寄与しないガス冷媒をバイパスさせるので蒸発器での冷媒圧力損失を低減でき、蒸発圧力を上昇させることができる。これにより、圧縮機１の電気入力を低減でき、その結果、空気調和装置３００の省エネ性を向上させることができる。なお、ガス冷媒をバイパスさせる量は、制御手段２０が流量制御弁１１の開度を制御することで調節される。 (Effects of the air-conditioning apparatus 300 according to Embodiment 1: in the case of cooling operation)
In the air conditioning apparatus 300 according to the first embodiment, a bypass pipe 10 that bypasses the gas refrigerant in the receiver 5 to the suction side of the compressor 1 is provided, and the gas refrigerant that does not contribute to evaporation is bypassed by the indoor heat exchanger 3. Therefore, the refrigerant pressure loss in the evaporator can be reduced, and the evaporation pressure can be increased. Thereby, the electrical input of the compressor 1 can be reduced, As a result, the energy-saving property of the air conditioning apparatus 300 can be improved. The amount of bypassing the gas refrigerant is adjusted by the control means 20 controlling the opening degree of the flow control valve 11.

外気温度、室内負荷などの急激な変化などが生じた場合には、レシーバ５内に貯留される二相冷媒の一時的な増加、あるいはレシーバ５に流入する二相冷媒の流量の増加などが生じる。このため、暖房運転で説明したように、バイパス配管１０に液冷媒が流入する場合がある。 When a sudden change such as the outside air temperature or the indoor load occurs, the two-phase refrigerant stored in the receiver 5 temporarily increases or the flow rate of the two-phase refrigerant flowing into the receiver 5 increases. . For this reason, the liquid refrigerant may flow into the bypass pipe 10 as described in the heating operation.

一方、本実施の形態１に係る空気調和装置３００は、熱回収部９を有するとともに、バイパス配管１０の他方を、吸入配管８のうち四方弁２と熱回収部９との間に接続したものである。このため、バイパス配管１０に液冷媒が流入しても、この流入した液冷媒は、バイパス配管１０の下流側に位置する熱回収部９に流れ込む。この熱回収部９に流れ込んだ液冷媒は、レシーバ５に貯留される冷媒から熱を受け取って蒸発ガス化する。このため、本実施の形態１に係る空気調和装置３００は、バイパス配管１０に液冷媒が流入してしまっても、圧縮機１の吸入側に液冷媒が流れ込むことが抑制され、圧縮機１の信頼性を損なうことが抑制される。すなわち、本実施の形態１に係る空気調和装置３００は、圧縮機１の信頼性を確保することができる。 On the other hand, the air-conditioning apparatus 300 according to Embodiment 1 has the heat recovery unit 9 and the other of the bypass pipes 10 connected between the four-way valve 2 and the heat recovery unit 9 in the suction pipe 8. It is. For this reason, even if the liquid refrigerant flows into the bypass pipe 10, the liquid refrigerant that has flowed in flows into the heat recovery unit 9 located on the downstream side of the bypass pipe 10. The liquid refrigerant that has flowed into the heat recovery unit 9 receives heat from the refrigerant stored in the receiver 5 and evaporates. For this reason, the air-conditioning apparatus 300 according to the first embodiment suppresses the liquid refrigerant from flowing into the suction side of the compressor 1 even when the liquid refrigerant flows into the bypass pipe 10. Impairing reliability is suppressed. That is, the air conditioning apparatus 300 according to Embodiment 1 can ensure the reliability of the compressor 1.

実施の形態２．
図２は、実施の形態２に係る空気調和装置３０１の冷媒回路構成の一例である。なお、本実施の形態２では、実施の形態１と同一部分には同一符号とし、実施の形態１との相違点を中心に説明するものとする。 Embodiment 2. FIG.
FIG. 2 is an example of a refrigerant circuit configuration of the air-conditioning apparatus 301 according to Embodiment 2. In the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and differences from the first embodiment will be mainly described.

実施の形態２において、室外熱交換器７にはヘッダ型分配器が用いられている。このため、室外熱交換器７は、並列の関係にある複数の冷媒流路を有している。ここで、冷媒流路とは熱交換器の伝熱管に対応するものである。そして、室外熱交換器７は、室外熱交換器７の冷媒流入側（入口側）に取り付けられ、室外熱交換器７に供給された冷媒を複数の冷媒流路に分配するのに利用される第１のヘッダと、室外熱交換器７の冷媒流出側（出口側）に取り付けられ、複数の冷媒流路の冷媒を合流させる第２のヘッダとを有するものである。 In the second embodiment, a header type distributor is used for the outdoor heat exchanger 7. For this reason, the outdoor heat exchanger 7 has a plurality of refrigerant channels in a parallel relationship. Here, the refrigerant flow path corresponds to the heat transfer tube of the heat exchanger. The outdoor heat exchanger 7 is attached to the refrigerant inflow side (inlet side) of the outdoor heat exchanger 7 and is used to distribute the refrigerant supplied to the outdoor heat exchanger 7 to a plurality of refrigerant flow paths. The first header and a second header that is attached to the refrigerant outflow side (outlet side) of the outdoor heat exchanger 7 and joins the refrigerants in the plurality of refrigerant channels.

熱交換器の高性能化（たとえば、熱交換効率の向上など）の手法として冷媒が流れる伝熱管を細径化する手法がある。この場合、細径化による冷媒圧力損失増加を抑制するために、冷媒の分岐数（パス数）を増加させること（多パス分配）が必要になる。
伝熱管の直径が約７ｍｍの場合には、業務用の空気調和装置では冷媒の分岐数は２０前後であるが、伝熱管の直径が約３ｍｍ以下の場合には、分岐数が４０前後かそれ以上となる。通常の空気調和装置の動作条件における蒸発器入口側の二相冷媒の乾き度（約０．１〜約０．３）では、二相冷媒を均等な量に多パス分配することは難しく、蒸発器への冷媒分布に偏りが生じ、熱交換器の本来持つ性能が発揮できない場合が多い。
なお、冷媒分布の偏りは、たとえば重力の作用などにより、上側の冷媒流路よりも下側の方に液冷媒が流れやすい、あるいは二相冷媒中のガス冷媒により液冷媒が上側の冷媒流路に押し上げられるなどに起因している。 As a technique for improving the performance of the heat exchanger (for example, improving the heat exchange efficiency), there is a technique of reducing the diameter of the heat transfer tube through which the refrigerant flows. In this case, it is necessary to increase the number of refrigerant branches (the number of passes) (multi-pass distribution) in order to suppress an increase in refrigerant pressure loss due to a reduction in diameter.
When the heat transfer tube diameter is about 7 mm, the commercial air conditioner has about 20 refrigerant branches. However, when the heat transfer tube diameter is about 3 mm or less, the branch number is about 40 or so. That's it. With the dryness of the two-phase refrigerant on the evaporator inlet side (about 0.1 to about 0.3) under normal air conditioner operating conditions, it is difficult to distribute the two-phase refrigerant in multiple passes evenly. In many cases, the refrigerant distribution to the heat exchanger is biased, and the performance inherent in the heat exchanger cannot be exhibited.
Note that the refrigerant distribution is biased by the fact that the liquid refrigerant tends to flow downward from the upper refrigerant flow path due to, for example, the action of gravity, or the liquid refrigerant flows upward due to the gas refrigerant in the two-phase refrigerant. It is caused by being pushed up.

本実施の形態２に係る空気調和装置３０１では、レシーバ５内のガス冷媒を圧縮機１の吸入側にバイパスするバイパス配管１０を設け、室内熱交換器３で蒸発に寄与しないガス冷媒をバイパスさせるように構成している。このため、暖房運転時において蒸発器となる室外熱交換器７の冷媒流入側となる第１のヘッダ型分配器２１の二相冷媒の乾き度を約０．１以下に低下させることができる。その結果、第１のヘッダ型分配器２１内が液冷媒単相の状態に近くなり、多パス分配による室外熱交換器７への冷媒分布の偏りが改善され、室外熱交換器７の性能が低減してしまうことが抑制される。 In the air conditioning apparatus 301 according to the second embodiment, a bypass pipe 10 that bypasses the gas refrigerant in the receiver 5 to the suction side of the compressor 1 is provided, and the gas refrigerant that does not contribute to evaporation is bypassed by the indoor heat exchanger 3. It is configured as follows. For this reason, the dryness of the two-phase refrigerant of the first header-type distributor 21 on the refrigerant inflow side of the outdoor heat exchanger 7 serving as an evaporator during the heating operation can be reduced to about 0.1 or less. As a result, the inside of the first header type distributor 21 is close to a liquid refrigerant single-phase state, the uneven distribution of the refrigerant distribution to the outdoor heat exchanger 7 due to multi-pass distribution is improved, and the performance of the outdoor heat exchanger 7 is improved. The reduction is suppressed.

なお、図２では室外熱交換器７が伝熱管の細径化により多分岐になる場合を説明したが、室内熱交換器３が伝熱管の細径化により多分岐になる場合でも、室内熱交換器３側に多パス分岐を行うヘッダを設ければ、室内熱交換器３が蒸発器となる場合（冷房運転）でも同様の効果を有する。 Note that FIG. 2 illustrates the case where the outdoor heat exchanger 7 becomes multi-branched by reducing the diameter of the heat transfer tube. However, even if the indoor heat exchanger 3 becomes multi-branched by reducing the diameter of the heat transfer tube, the indoor heat If a header that performs multi-pass branching is provided on the exchanger 3 side, the same effect can be obtained even when the indoor heat exchanger 3 is an evaporator (cooling operation).

実施の形態３．
図３は、実施の形態３に係る空気調和装置３０２の冷媒回路構成の一例である。なお、本実施の形態３では、実施の形態２と同一部分には同一符号とし、実施の形態２との相違点を中心に説明するものとする。 Embodiment 3 FIG.
FIG. 3 is an example of a refrigerant circuit configuration of the air-conditioning apparatus 302 according to Embodiment 3. In the third embodiment, the same parts as those in the second embodiment are denoted by the same reference numerals, and differences from the second embodiment will be mainly described.

実施の形態３に係る空気調和装置３０２は、暖房運転時に蒸発器として機能する室外熱交換器７の複数の冷媒流路（伝熱管）のうちの少なくとも２つに設けられ、室外熱交換器７の冷媒流出側の温度を検出する複数の温度検出手段１３と、複数の温度検出手段１３の検出結果に基づいて流量制御弁１１の開度を制御する制御手段２０とを備えているものである。そして、制御手段２０は、複数の温度検出手段１３の検出結果に基づいて複数の冷媒流路ごとに冷媒の過熱度を算出し、算出した複数の過熱度の値に基づいて流量制御弁１１の開度を制御する。このように、空気調和装置３０２は、温度検出手段１３の検出結果に基づいて流量制御弁１１の開度を制御し、バイパス配管１０を介して圧縮機１の吸入側に戻すガス冷媒の量を調整するものである。 The air conditioner 302 according to Embodiment 3 is provided in at least two of the plurality of refrigerant channels (heat transfer tubes) of the outdoor heat exchanger 7 that functions as an evaporator during heating operation, and the outdoor heat exchanger 7 A plurality of temperature detection means 13 for detecting the temperature of the refrigerant outflow side, and a control means 20 for controlling the opening degree of the flow control valve 11 based on the detection results of the plurality of temperature detection means 13. . And the control means 20 calculates the superheat degree of a refrigerant | coolant for every some refrigerant | coolant flow path based on the detection result of the several temperature detection means 13, and the flow control valve 11 of the flow control valve 11 based on the calculated value of several superheat degrees. Control the opening. Thus, the air conditioner 302 controls the opening degree of the flow rate control valve 11 based on the detection result of the temperature detection means 13, and sets the amount of gas refrigerant to be returned to the suction side of the compressor 1 via the bypass pipe 10. To be adjusted.

なお、複数の温度検出手段１３は、暖房運転時に蒸発器となる室外熱交換器７の冷媒出口側の第２のヘッダ型分配器２２に設けられている。また、図３では温度検出手段１３が３個設けられている場合を例に示している。また、温度検出手段１３としては、たとえば熱電対や、サーミスタなどを用いることができる。 In addition, the several temperature detection means 13 is provided in the 2nd header type | mold divider | distributor 22 by the side of the refrigerant | coolant outlet of the outdoor heat exchanger 7 used as an evaporator at the time of heating operation. FIG. 3 shows an example in which three temperature detecting means 13 are provided. Moreover, as the temperature detection means 13, a thermocouple, a thermistor, etc. can be used, for example.

多パス分配による蒸発器への冷媒分布の偏りが発生すると、蒸発器出口側の冷媒過熱度にばらつきが生じる。本実施の形態３に係る空気調和装置３０２では、蒸発器出口側の温度を複数の温度検出手段１３で検出し、制御手段２０は、この検出した温度に基づいてそれぞれの冷媒流路の過熱度を算出する。そして、制御手段２０は、これらの算出した過熱度の値が予め設定された値になるように、流量制御弁１１を制御する。なお、過熱度についての予め設定された値とは、複数の温度検出手段１３が設置された冷媒流路ごとに設定される値である。これにより、多パス分配による蒸発器への冷媒分布の偏りが改善され、室外熱交換器７の性能が低減してしまうことが抑制される。なお、この時、第２膨張弁６の弁開度は一定値に固定しても良い。 When the distribution of the refrigerant distribution to the evaporator due to multi-pass distribution occurs, the refrigerant superheat degree on the evaporator outlet side varies. In the air conditioner 302 according to the third embodiment, the temperature at the outlet side of the evaporator is detected by the plurality of temperature detection means 13, and the control means 20 determines the degree of superheat of each refrigerant channel based on the detected temperature. Is calculated. Then, the control means 20 controls the flow rate control valve 11 so that these calculated superheat values become preset values. The preset value for the degree of superheat is a value set for each refrigerant flow path in which a plurality of temperature detection means 13 are installed. Thereby, the bias of the refrigerant distribution to the evaporator due to the multi-pass distribution is improved, and the performance of the outdoor heat exchanger 7 is suppressed from being reduced. At this time, the opening degree of the second expansion valve 6 may be fixed to a constant value.

なお、図３では室外熱交換器７が伝熱管の細径化により多分岐になる場合を説明したが、室内熱交換器３が伝熱管の細径化により多分岐になる場合でも、室内熱交換器３側に多パス分岐を行うヘッダを設ければ、室内熱交換器３が蒸発器となる場合（冷房運転）でも同様の効果を有する。 In addition, although FIG. 3 demonstrated the case where the outdoor heat exchanger 7 became multi-branch by diameter reduction of a heat exchanger tube, even when the indoor heat exchanger 3 becomes multi-branch by diameter reduction of a heat exchanger tube, indoor heat If a header that performs multi-pass branching is provided on the exchanger 3 side, the same effect can be obtained even when the indoor heat exchanger 3 is an evaporator (cooling operation).

なお、上述した蒸発器出口側の冷媒過熱度のばらつきとは、液冷媒だけでなく、ガス冷媒が混入しやすいかどうかということも指している。すなわち、レシーバ５の冷媒配管５０Ｃ側から流出する冷媒は、主に液冷媒であるが、ガス冷媒も混入している。蒸発器の複数の冷媒流路は、液冷媒が供給されやすい流路もあれば、ガス冷媒が供給されやすい流路もある。このガス冷媒が供給されやすい冷媒流路では、液冷媒に混じってガス冷媒が供給されやすい分、この冷媒流路に設けられた温度検出手段１３の検出結果がばらつきやすく、その結果として過熱度の値もばらつきやすくなる。 Note that the above-described variation in the degree of superheat of the refrigerant on the outlet side of the evaporator also indicates whether not only liquid refrigerant but also gas refrigerant is likely to be mixed. That is, the refrigerant flowing out from the refrigerant pipe 50C side of the receiver 5 is mainly liquid refrigerant, but gas refrigerant is also mixed therein. The plurality of refrigerant channels of the evaporator include a channel through which liquid refrigerant is easily supplied and a channel through which gas refrigerant is easily supplied. In the refrigerant flow path where the gas refrigerant is easily supplied, the detection result of the temperature detection means 13 provided in the refrigerant flow path is likely to vary because the gas refrigerant is likely to be mixed with the liquid refrigerant. The value also tends to vary.

実施の形態４．
図４は、実施の形態４に係る空気調和装置３０３の冷媒回路構成の一例である。なお、本実施の形態４では、実施の形態３と同一部分には同一符号とし、実施の形態３との相違点を中心に説明するものとする。 Embodiment 4 FIG.
FIG. 4 is an example of a refrigerant circuit configuration of the air-conditioning apparatus 303 according to Embodiment 4. In the fourth embodiment, the same parts as those in the third embodiment are denoted by the same reference numerals, and differences from the third embodiment will be mainly described.

本実施の形態４では、実施の形態３とは異なり、複数の冷媒流路（伝熱管）に温度検出手段１３を設置したのではなく、１つの冷媒流路に温度検出手段１３を設置している。その他の点では、実施の形態３と同様である。実施の形態４に係る空気調和装置３０３は、温度検出手段１３が設置される冷媒流路を、複数の冷媒流路のうち過熱度のばらつきが生じやすい冷媒流路としている。蒸発器の冷媒流路の冷媒分布と冷媒流路の過熱度との間には関連性があるからである。すなわち、多パス分配による蒸発器への冷媒分布の偏りが発生すると、蒸発器出口側の冷媒過熱度にばらつきが生じるということである。
なお、複数の冷媒流路のうちの最上段の冷媒流路は、特に、過熱度のばらつきが生じやすい冷媒流路である。このため、図４に示すように、実施の形態４では、温度検出手段１３が最上段の冷媒流路に設置されている場合を例として説明する。 In the fourth embodiment, unlike the third embodiment, the temperature detection means 13 is not installed in a plurality of refrigerant flow paths (heat transfer tubes), but the temperature detection means 13 is installed in one refrigerant flow path. Yes. The other points are the same as in the third embodiment. In the air conditioner 303 according to Embodiment 4, the refrigerant flow path in which the temperature detection means 13 is installed is a refrigerant flow path in which the degree of superheat is likely to vary among the plurality of refrigerant flow paths. This is because there is a relationship between the refrigerant distribution of the refrigerant flow path of the evaporator and the degree of superheat of the refrigerant flow path. That is, if the distribution of the refrigerant distribution to the evaporator due to multi-pass distribution occurs, the refrigerant superheat degree on the evaporator outlet side varies.
It should be noted that the uppermost refrigerant flow channel among the plurality of refrigerant flow channels is a refrigerant flow channel that is particularly susceptible to variations in the degree of superheat. For this reason, as shown in FIG. 4, Embodiment 4 demonstrates as an example the case where the temperature detection means 13 is installed in the uppermost refrigerant | coolant flow path.

本実施の形態４に係る空気調和装置３０３では、複数の冷媒流路のうち過熱度のばらつきが生じやすい冷媒流路に温度検出手段１３を設置したものである。さらに、温度検出手段１３は、その冷媒流路のうちの蒸発器出口側の位置に配置される。このように、実施の形態４では、冷媒分布により敏感に応答する蒸発器出口側の温度を温度検出手段１３で検出し、この検出された温度に基づいて制御手段２０が過熱度の値を算出する。そして、制御手段２０は、算出した過熱度が予め設定された値になるように、流量制御弁１１の開度を制御し、バイパス配管１０を介して圧縮機１の吸入側に戻されるガス冷媒の量を調節する。これにより、より簡素な方法で、パス分配による蒸発器への冷媒分布の偏りが改善され、室外熱交換器７の性能が低減してしまうことが抑制される。なお、この時、第２膨張弁６の弁開度は一定値に固定してもよい。 In the air conditioner 303 according to the fourth embodiment, the temperature detection unit 13 is installed in a refrigerant flow path in which a variation in superheat degree is likely to occur among a plurality of refrigerant flow paths. Furthermore, the temperature detection means 13 is arrange | positioned in the position of the evaporator exit side among the refrigerant | coolant flow paths. As described above, in the fourth embodiment, the temperature detection means 13 detects the temperature at the evaporator outlet side that responds more sensitively to the refrigerant distribution, and the control means 20 calculates the superheat value based on the detected temperature. To do. And the control means 20 controls the opening degree of the flow control valve 11 so that the calculated superheat degree becomes a preset value, and the gas refrigerant returned to the suction side of the compressor 1 via the bypass pipe 10 Adjust the amount. Thereby, the bias of the refrigerant distribution to the evaporator by the path distribution is improved by a simpler method, and the performance of the outdoor heat exchanger 7 is suppressed from being reduced. At this time, the opening degree of the second expansion valve 6 may be fixed to a constant value.

実施の形態５．
本実施の形態５では、レシーバ５内のガス冷媒を、バイパス配管１０を介して圧縮機１の吸入側に戻すにあたり、蒸発器側の膨張弁の弁開度を全開とするものである。すなわち、暖房運転時においては、室外熱交換器７が蒸発器として機能するので、蒸発器側の膨張弁である第２膨張弁６の開度を全開とする。また、冷房運転時においては、室内熱交換器３が蒸発器として機能するので、蒸発器側の膨張弁である第１膨張弁４の開度を全開とする。 Embodiment 5 FIG.
In the fifth embodiment, when the gas refrigerant in the receiver 5 is returned to the suction side of the compressor 1 via the bypass pipe 10, the opening degree of the expansion valve on the evaporator side is fully opened. That is, during the heating operation, since the outdoor heat exchanger 7 functions as an evaporator, the opening degree of the second expansion valve 6 that is an expansion valve on the evaporator side is fully opened. Further, during the cooling operation, the indoor heat exchanger 3 functions as an evaporator, so that the opening degree of the first expansion valve 4 that is an expansion valve on the evaporator side is fully opened.

暖房運転時において、第２膨張弁６の開度を全開にしないと、バイパス配管１０にガス冷媒をバイパスさせた後の、レシーバ５に残る液冷媒は第２膨張弁６で減圧されて低圧になる。このため、蒸発器である室外熱交換器７に流入する二相冷媒の乾き度が上昇することになる。 If the opening of the second expansion valve 6 is not fully opened during the heating operation, the liquid refrigerant remaining in the receiver 5 after the gas refrigerant is bypassed in the bypass pipe 10 is reduced in pressure by the second expansion valve 6 to a low pressure. Become. For this reason, the dryness of the two-phase refrigerant flowing into the outdoor heat exchanger 7 as an evaporator increases.

本実施の形態５では、暖房運転時において、第２膨張弁６の開度を全開とし、レシーバ５内が減圧されるようにする。これにより、バイパス配管１０にガス冷媒をバイパスさせた後の、レシーバ５に残る液冷媒の乾き度の上昇が抑制される。すなわち、本実施の形態５に係る空気調和装置では、暖房運転時において、蒸発器として機能する室外熱交換器７に流入する二相冷媒の乾き度を低く抑える効果があり、蒸発器での冷媒圧力損失を低減でき、蒸発圧力を上昇させることができる。これにより、圧縮機１の電気入力を低減でき、その結果、空気調和装置の省エネ性を向上させることができる。なお、上記では、暖房運転時についての説明をしたが、冷房運転時には、第１膨張弁４を全開にすることで同様の効果を得ることができる。 In the fifth embodiment, during the heating operation, the opening of the second expansion valve 6 is fully opened, and the interior of the receiver 5 is decompressed. Thereby, the increase in the dryness of the liquid refrigerant remaining in the receiver 5 after the gas refrigerant is bypassed in the bypass pipe 10 is suppressed. That is, the air-conditioning apparatus according to Embodiment 5 has an effect of reducing the dryness of the two-phase refrigerant flowing into the outdoor heat exchanger 7 functioning as an evaporator during heating operation, and the refrigerant in the evaporator Pressure loss can be reduced and evaporation pressure can be increased. Thereby, the electrical input of the compressor 1 can be reduced, As a result, the energy-saving property of an air conditioning apparatus can be improved. In the above description, the heating operation is described, but the same effect can be obtained by fully opening the first expansion valve 4 during the cooling operation.

実施の形態６．
本実施の形態６に係る空気調和装置の冷媒回路では、バイパス配管１０で吸入配管８に戻すガス冷媒に液冷媒を混入させて吸入配管８に液バックさせるものである。吸入配管８に液バックさせても本実施の形態６に係る空気調和装置の冷媒回路では、バイパス配管１０を熱回収部９と四方弁２との間に設けたので、バイパス配管１０を通してレシーバ５内の液冷媒が吸入配管８に流入した場合でも、液冷媒は熱回収部９によりガス化されるので、圧縮機１の信頼性が確保される。 Embodiment 6 FIG.
In the refrigerant circuit of the air-conditioning apparatus according to Embodiment 6, the liquid refrigerant is mixed into the gas refrigerant that is returned to the suction pipe 8 by the bypass pipe 10 and is liquid-backed to the suction pipe 8. In the refrigerant circuit of the air-conditioning apparatus according to Embodiment 6 even if the liquid is returned to the suction pipe 8, the bypass pipe 10 is provided between the heat recovery unit 9 and the four-way valve 2. Even when the liquid refrigerant inside flows into the suction pipe 8, the liquid refrigerant is gasified by the heat recovery unit 9, so that the reliability of the compressor 1 is ensured.

レシーバ５からバイパス配管１０を通してガス冷媒をバイパスさせる場合、レシーバ５内に貯留する二相冷媒の内で、液バックさせずにバイパスできるガス冷媒量の割合はレシーバ５の構造にも依存するが、およそ３０％〜６０％程度である。このため、液バックさせずにガス冷媒をバイパスさせる場合には、蒸発器での冷媒圧力損失の低減量は制限されるので、空気調和装置の性能（省エネ性）向上は制限される。 When the gas refrigerant is bypassed from the receiver 5 through the bypass pipe 10, the ratio of the amount of gas refrigerant that can be bypassed without liquid back in the two-phase refrigerant stored in the receiver 5 depends on the structure of the receiver 5. About 30% to 60%. For this reason, when the gas refrigerant is bypassed without liquid back, the reduction amount of the refrigerant pressure loss in the evaporator is limited, so that the performance (energy saving) improvement of the air conditioner is limited.

本実施の形態６に係る空気調和装置は、吸入配管８に戻すガス冷媒に液冷媒を混入させて吸入配管８に液バックさせるものである。こうすることでレシーバ５内に貯留する二相冷媒の内で、液バックさせずにバイパスできるガス冷媒量の割合を９０％程度まで増加できる。このため、蒸発器での冷媒圧力損失はより低減され、圧縮機１の信頼性を確保しつつ空気調和装置の性能（省エネ性）をより向上させることができる。 In the air conditioner according to the sixth embodiment, the liquid refrigerant is mixed into the gas refrigerant returned to the suction pipe 8 and the liquid is returned to the suction pipe 8. By doing so, the ratio of the amount of gas refrigerant that can be bypassed without causing liquid back in the two-phase refrigerant stored in the receiver 5 can be increased to about 90%. For this reason, the refrigerant | coolant pressure loss in an evaporator is reduced more, and the performance (energy-saving property) of an air conditioning apparatus can be improved more, ensuring the reliability of the compressor 1. FIG.

１圧縮機、２四方弁、３室内熱交換器、４第１膨張弁、５レシーバ、６第２膨張弁、７室外熱交換器、８吸入配管、９熱回収部、１０バイパス配管、１１流量制御弁、１３温度検出手段、２０制御手段、２１第１のヘッダ型分配器、２２第２のヘッダ型分配器、５０Ａ冷媒配管、５０Ｂ冷媒配管、５０Ｃ冷媒配管、５０Ｄ冷媒配管、１００室外ユニット、２００室内ユニット、３００空気調和装置、３０１空気調和装置、３０２空気調和装置、３０３空気調和装置。 DESCRIPTION OF SYMBOLS 1 Compressor, 2 Four way valve, 3 Indoor heat exchanger, 4 1st expansion valve, 5 Receiver, 6 2nd expansion valve, 7 Outdoor heat exchanger, 8 Intake piping, 9 Heat recovery part, 10 Bypass piping, 11 Flow rate Control valve, 13 Temperature detecting means, 20 Control means, 21 First header type distributor, 22 Second header type distributor, 50A Refrigerant pipe, 50B Refrigerant pipe, 50C Refrigerant pipe, 50D Refrigerant pipe, 100 Outdoor unit, 200 indoor unit, 300 air conditioner, 301 air conditioner, 302 air conditioner, 303 air conditioner.

Claims

In an air conditioner having a refrigeration cycle configured by connecting a compressor, a condenser, an expansion valve, and an evaporator with refrigerant piping,
A suction pipe, one connected to the suction side of the compressor and the other connected to the evaporator;
A receiver connected to a refrigerant pipe connecting the evaporator and the condenser;
One bypass is connected to the receiver, the other is connected to the suction pipe, and a bypass pipe that supplies the refrigerant in the receiver to the suction pipe;
Heat recovery that is provided on the downstream side of the connection position with the bypass pipe in the suction pipe, and exchanges heat between the refrigerant flowing into the suction pipe from the evaporator side and the bypass pipe side and the refrigerant in the receiver. And
An air conditioner comprising:

The heat recovery unit is
The air conditioner according to claim 1, wherein a part of the suction pipe is arranged in the receiver.

The evaporator is
A plurality of heat transfer tubes in a parallel relationship;
A header-type distributor attached to the refrigerant inflow side of the evaporator and used to distribute the refrigerant supplied to the evaporator to the plurality of heat transfer tubes. The air conditioning apparatus described in 1.

A flow control valve connected to the bypass pipe;
A temperature detecting means provided on the heat transfer tube of the evaporator for detecting a temperature of a refrigerant outflow side of the evaporator;
Control means for controlling the opening of the flow control valve based on the detection result of the temperature detection means,
The control means includes
The air conditioner according to claim 3, wherein the opening degree of the flow rate control valve is controlled based on a detection result of the temperature detection means.

The temperature detecting means includes
Provided in at least two of the plurality of heat transfer tubes of the evaporator;
The control means includes
The air conditioner according to claim 4, wherein the opening degree of the flow rate control valve is controlled based on detection results of the plurality of temperature detection means.

The temperature detecting means includes
Among the plurality of heat transfer tubes, provided in the heat transfer tubes that are likely to vary in the degree of superheat,
The control means includes
The air conditioner according to claim 4, wherein the opening degree of the flow control valve is controlled based on a detection result of the temperature detection means.

The control means includes
The degree of superheat of the refrigerant is calculated based on the detection result of the temperature detecting means, and the opening degree of the flow rate control valve is controlled based on the calculated value of the superheat degree. Air conditioner.

Comprising control means for controlling the opening of the expansion valve;
The expansion valve is
Connected between the receiver and the evaporator;
The control means includes
The opening degree of the expansion valve is fully opened when returning the gas refrigerant in the receiver to the compressor via the bypass pipe. Air conditioner.

The liquid refrigerant that has flowed into the suction pipe via the bypass pipe is returned to the compressor after being gasified by the heat recovery unit. Air conditioner.