JP2004101150A

JP2004101150A - Air-conditioner

Info

Publication number: JP2004101150A
Application number: JP2002267537A
Authority: JP
Inventors: Ryoichi Takato; 高藤　亮一; Shoji Takaku; 高久　昭二; Masayuki Nonaka; 野中　正之; Hiroo Nakamura; 中村　啓夫; Kazutoshi Ota; 太田　和利
Original assignee: Hitachi Home and Life Solutions Inc
Current assignee: Hitachi Appliances Inc
Priority date: 2002-09-13
Filing date: 2002-09-13
Publication date: 2004-04-02

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air-conditioner of improved performance by enhancing the vapor-liquid separation efficiency while maintaining the quantity of sealed refrigerant in a vapor-liquid separation cycle. <P>SOLUTION: The air-conditioner has an auxiliary heat exchanger having a configuration in which a pipe line at an outlet of an outdoor heat exchanger forms one system or the pipe line forms one system when the outdoor heat exchanger works as a condenser. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は冷暖房や除湿を行う空気調和機に関する。
【０００２】
【従来の技術】
従来の空気調和機において、絞り装置と室内熱交換器との間の管路に気液分離器を設け、冷房運転時に絞り装置により減圧した低圧冷媒を気液分離し、この分離したガス冷媒を直接圧縮機吸込側の管路へ流し、室内熱交換器へは液冷媒のみを流すことで、室内熱交換器および接続配管などの低圧側配管での圧力損失を低減して性能の向上を図ったものがある。このような空気調和機として、特開平７−１２００７６号公報（特許文献１）、特開２００２−８９９８８号公報（特許文献２）に記載されたものが知られている。この空気調和機では気液分離器から圧縮機吸込側の管路の間にバイパス管路を設け、このバイパス管路中にキャピラリーチューブおよび開閉弁を設けている。
【０００３】
【特許文献１】
特開平７−１２００７６号公報（図１）
【特許文献２】
特開２００２−８９９８８号公報（図１）
【０００４】
【発明が解決しようとする課題】
図６の破線は図７に示すような気液分離器がついていない冷凍サイクルの冷媒の流れをモリエ線図に示したものである。図７において、四方弁１２は冷房サイクルを構成するように切替えられており、圧縮機１１によって圧縮された冷媒は、実践で示すように四方弁１２、室外熱交換器１３、絞り装置１４、室内熱交換器１５の順に流れる。
【０００５】
図６において、圧縮機１１を出た冷媒は７−８−９−１０のように順次状態が変化する。この冷凍サイクルに対し、図６の実線は図８に示した上記公報に記載された従来の空気調和機の冷媒の流れをモリエ線図に示したものである。
【０００６】
図８において、圧縮機１１を出た高温高圧のガスは凝縮器１３によりモリエ線図１−２のように凝縮し、絞り装置１４により２−３で減圧される。モリエ線図の３で気液分離器１８内に流れた冷媒は４，５のようにガスと液に分離する。ガスはバイパス流路（２方弁１９とキャピラリーチューブ２０が直列接続された）を通ってキャピラリチューブ２０で５−６のように減圧され、圧縮機１１の吸込側の管路に流れる。液は４−６のように蒸発器１５により蒸発し、６でバイパスされたガスと合流して圧縮機１１へ戻る。３での二相冷媒の渇き度は約０．２であり、冷媒のガスと液の質量流量比は２０％と８０％である。このため４−６を流れる蒸発器１５内の冷媒流量は全流量の８０％となり、気液分離器１８がない冷凍サイクルに比べ圧力損失が６０〜７０％程度まで減少する。また、蒸発能力は冷媒流量が減少するものの、気液分離器１８により蒸発器１５の入口の渇き度が減少するためエンタルピー差は増大し、気液分離器１８のない冷凍サイクルでの蒸発能力とほぼ等しくなる。したがって、蒸発器１５や低圧側の接続配管の圧力損失が減少することで、圧縮機仕事が減少し、冷凍サイクルの運転効率（ＣＯＰ）が向上する。
【０００７】
ところが、この従来の空気調和機では、冷房運転時に気液分離器１８より室内側（室内熱交換器１５）へ出た冷媒の乾き度が小さいため、気液分離器１８がない冷凍サイクルに比べ、気液分離器１８や接続配管、蒸発器１５での液冷媒の割合が増加し、最適な封入冷媒量が増加するという問題がある。このことは、低外温時に室外機の中の液冷媒滞留量が多くなり、冷凍機油がより多く冷媒へ溶解するため潤滑不良となったり、起動時の液圧縮により圧縮機１１への負担が大きくなるため圧縮機１１の信頼性の低下を招く。また、封入冷媒量の増加は地球環境保護の観点から好ましくない。
【０００８】
本発明は上記のことを鑑みてなされたもので、本発明の目的は、気液分離器を付けることによる最適な封入冷媒量の増分を可能な限り少なくすることで圧縮機の信頼性を満足しながら効率を向上させた空気調和機を提供することである。
【０００９】
【課題を解決するための手段】
上記目的は、圧縮機と、この圧縮機に接続された運転切換弁と、この運転切換弁に接続された室外熱交換器と、この室外機に接続された絞り装置と、この絞り装置接続された気液分離器と、この気液分離機及び前記運転切換弁に接続された室内熱交換器と、前記気液分離器と圧縮機吸込管路を接続するバイパス管路と、このバイパス管路途中に設けられた二方弁とを備えた空気調和機において、前記室外熱交換器が凝縮器として作用する場合に、その出口の管路がこの室外熱交換器内で１系統となるような管路構成とすることにより達成される。
【００１０】
また上記目的は、圧縮機と、この圧縮機に接続された運転切換弁と、この運転切換弁に接続された室外熱交換器と、この室外機に接続された絞り装置と、この絞り装置接続された気液分離器と、この気液分離機及び前記運転切換弁に接続された室内熱交換器と、前記気液分離器と圧縮機吸込管路を接続するバイパス管路と、このバイパス管路途中に設けられた二方弁とを備えた空気調和機において、前記室外熱交換器が凝縮器として作用する場合に、その出口に管路が１系統となる補助熱交換器を設けることにより達成される。
【００１１】
【発明の実施の形態】
以下、本発明の第一の実施例を図８に示す空気調和機の系統図に基づいて説明する。
【００１２】
図８において１１は圧縮機、１２は冷房サイクルと暖房サイクルを切換える運転切換弁である四方弁、１３は室外熱交換器、１４は冷房運転及び暖房運転の時に絞り作用を行う電動膨張弁等の絞り装置、１５は室内熱交換器である。また、１８は気液分離器、１９は全閉可能な二方弁、２０はキャピラリーチューブ等の減圧装置である。１９、２０は全閉可能な電動膨張弁等で代用も可能である。
【００１３】
これらは、冷媒配管により順次接続されて冷凍サイクルを構成する。ただし、１９、２０を含む管路は気液分離器１８と圧縮機１１の吸込管路を結ぶバイパス管路となっている。
【００１４】
以上のように構成された空気調和機の動作について説明する。冷房運転時、冷媒は図８の実線矢印の方向に流れる。圧縮機１１で圧縮された冷媒は室外熱交換器１３で凝縮して空気へ放熱し、絞り装置１４によって減圧膨張し、気液分離器１８により液とガスに分離される。液冷媒は室内熱交換器１５で蒸発して空気から吸熱して圧縮機１１へ戻り、ガス冷媒は二方弁１９を開くことで、キャピラリーチューブ２０によって圧縮機１１へ液が戻らない最適な減圧量で減圧され圧縮機へ戻る。
【００１５】
上記動作をする空気調和機において、室外熱交換器１３の管路構成を図１と図２で比較する。冷媒は実線矢印の方向に流れる。流れは管路２１で２系統に別れ、その後管路２２、２３で４系統となり、管路２４で再び２系統となる。図２は熱交換器を出た後に１系統に合流するが、図１は管路２４で凝縮した液冷媒が熱交換器下部で１系統に合流することで、流速が上がって管内熱伝達率が高くなり、図２よりも過冷却度が十分取れた状態となる。
【００１６】
気液分離器１８がない最適な冷媒量による冷凍サイクルを図９のモリエ線図の破線に示す。仮にこれと同じ冷媒量で気液分離器１８を設け、室内側への液冷媒の割合を増加すると、気液分離サイクルにより蒸発側のエンタルピー差が広がっても、冷媒流量が低下するため、冷媒不足の冷凍サイクルとなり冷房能力は低下する。このためモリエ線図は図９の実線のように凝縮圧力、過冷却度が減少すし、性能は低下してしまう。このため封入冷媒量を増やす必要が生じる。
【００１７】
しかし、封入冷媒量の増加は、低外温時に室外機の中の液冷媒滞留量が多くなり、冷凍機油がより多く冷媒へ溶解するため潤滑不良となったり、起動時の液圧縮により圧縮機への負担が大きくなるため圧縮機の信頼性の低下を招く。また、封入冷媒量の増加は地球環境保護の観点から好ましくない。したがって上述した過冷却度が十分取れる図１の管路構成にすることで封入冷媒量の増分を抑えることができる。例えば、定格冷房能力２．８ｋＷのセパレート型ルームエアコンの場合を図１０に示す。図は横軸に冷媒追加量、縦軸に運転効率（ＣＯＰ）向上率をとったもので、実線４０は図１の管路構成、破線４１は図２の管路構成である。このグラフより図１の管路構成では図２に比べ冷媒量が約５０ｇ少なくても同等の運転効率（ＣＯＰ）向上率であることがわかる。
【００１８】
暖房運転時、冷媒は図８の破線矢印の方向に流れる。二方弁１９は閉じる。圧縮機１１で圧縮された冷媒は室内熱交換器１５で凝縮して空気へ放熱し、絞り装置１４によって減圧膨張し、室外熱交換器１３で蒸発して空気から吸熱して圧縮機１１へ戻る。このとき気液分離器１８内部には凝縮した液冷媒が滞留する。ルームエアコン等では室内熱交換器は通常室外熱交換器よりも小さいので暖房運転時の最適冷媒量は冷房運転時よりも少ない。したがって気液分離器１８が受液器の役割を果たすことで、冷房運転と暖房運転で冷媒量を調節でき、最適な運転状態にすることができる。
【００１９】
上記動作をする空気調和機において、室外熱交換器１３の管路構成を図１と図２で比較する。冷媒は破線矢印の方向に流れる。図１では管路２５の１系統から管路２４の２系統、図２では入口で管路２４の２系統となる。その後管路２２、２３で４系統となり、管路２１で再び２系統となる。
【００２０】
図２の管路構成に比べ図１の管路構成では入口の管路が１系統であるためガス冷媒の圧力損失が大きくなる。しかし、室外熱交換器１３が１系統の管路に比べて十分大きく、入口の二相冷媒の乾き度が小さいので、圧力損失の影響は少なくなり、気液分離器１８により冷媒量が最適に調整されるため性能の低下は、ほとんど問題ない。
【００２１】
したがって、図１の管路構成にすることで、暖房運転時に性能低下することなく、冷房運転時に気液分離器を付けることによる最適な封入冷媒量の増分を可能な限り少なくするできる。
【００２２】
本実施例では、室外熱交換器１３の管路構成を図１のように冷房運転時の入口管路を管路２２、管路２３の４系統としたが、図３のように冷房運転時の入口管路を管路２７の２系統とし、出口管路２８を１系統としたり、図４のように冷房運転時の入口管路を管路２９、３０の４系統とし、出口管路３１を１系統としてもよい。
【００２３】
次に、本発明の第二の実施例を図面に基づいて説明する。本実施例における空気調和機の系統図は第一の実施例と同様である。図５は本発明における室外熱交換器の具体的構成の別の例を示したものである。
【００２４】
冷房運転時、冷媒は図５の実線矢印の方向に流れる。流れは管路２１で２系統に別れ、その後管路２２、２３で４系統となり、管路２４で再び２系統となる。その後管路２４で凝縮した液冷媒は補助熱交換器２６で１系統に合流することで、流速が上がって管内熱伝達率が高くなり、過冷却度が十分取れた状態となる。第一の実施例と比較して１系統の管路を別体の補助熱交換器としたため、室外熱交換器１３の管路と伝熱管を異なるものにすることができる。例えば補助熱交換器の管径を小さくすれば、さらに管内熱伝達率が高くなり過冷却度を取ることができるので、冷房運転時の封入冷媒量の増加を抑えることができる。
【００２５】
暖房運転時、冷媒は図５の破線矢印の方向に流れる。流れは入口で補助熱交換器２６の１系統となる。その後２系統の管路２４を通って管路２２、２３で４系統となり、管路２１で再び２系統となる。補助熱交換器は１系統であるためガス冷媒の圧力損失が大きくなる。しかし、室外熱交換器１３が１系統の管路に比べて十分大きく、入口の二相冷媒の乾き度が小さいので、圧力損失の影響は少なくなり、気液分離器１８により冷媒量が最適に調整されるため性能の低下は、ほとんど問題ない。
【００２６】
したがって、図５の管路構成にすることで、暖房運転時に性能低下することなく、冷房運転時に気液分離器を付けることによる最適な封入冷媒量の増分を可能な限り少なくするできる。
【００２７】
【発明の効果】
以上の実施の形態から明らかなように、本発明によれば、室外熱交換器が凝縮器として作用する場合に、その出口の管路が一系統となるような管路構成、あるいは管路が一系統となるような補助熱交換器を設けることで、気液分離器を付けることによる最適な封入冷媒量の増分を可能な限り少なくするでき、圧縮機の信頼性を満足しながら効率を向上させることができる。
【図面の簡単な説明】
【図１】本発明の第一の実施例における室外熱交換器の管路構成図。
【図２】本発明の第一の実施例における室外熱交換器の管路構成図。
【図３】本発明の第一の実施例における室外熱交換器の管路構成図。
【図４】本発明の第一の実施例における室外熱交換器の管路構成図。
【図５】本発明の第二の実施例における室外熱交換器の管路構成図。
【図６】気液分離サイクルと通常サイクルの動作を示すモリエ線図。
【図７】気液分離器がない空気調和機の系統図。
【図８】気液分離器を有する空気調和機の系統図。
【図９】本発明の第一の実施例における動作を示すモリエ線図。
【図１０】本発明の第一の実施例における冷媒追加量とＣＯＰ効率向上率の関係図。
【符号の説明】
１１…圧縮機、１２…四方弁、１３…室外熱交換器、１４…絞り装置、１５…室内熱交換器、１８…気液分離器、１９…二方弁、２０…キャピラリーチューブ。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an air conditioner that performs cooling and heating and dehumidification.
[0002]
[Prior art]
In a conventional air conditioner, a gas-liquid separator is provided in a pipe between the expansion device and the indoor heat exchanger, and the low-pressure refrigerant depressurized by the expansion device during cooling operation is separated into gas and liquid. By flowing directly to the pipeline on the compressor suction side and flowing only the liquid refrigerant to the indoor heat exchanger, pressure loss in the indoor heat exchanger and low-pressure side piping such as connection piping is reduced, and performance is improved. There are things. As such an air conditioner, those described in Japanese Patent Application Laid-Open No. Hei 7-12076 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2002-89988 (Patent Document 2) are known. In this air conditioner, a bypass pipe is provided between the gas-liquid separator and a pipe on the compressor suction side, and a capillary tube and an on-off valve are provided in the bypass pipe.
[0003]
[Patent Document 1]
JP-A-7-12076 (FIG. 1)
[Patent Document 2]
JP-A-2002-89988 (FIG. 1)
[0004]
[Problems to be solved by the invention]
The broken line in FIG. 6 is a Mollier diagram showing the flow of the refrigerant in the refrigeration cycle without the gas-liquid separator as shown in FIG. In FIG. 7, the four-way valve 12 is switched so as to constitute a cooling cycle, and the refrigerant compressed by the compressor 11 is supplied to the four-way valve 12, the outdoor heat exchanger 13, the expansion device 14, the indoor It flows in the order of the heat exchanger 15.
[0005]
In FIG. 6, the state of the refrigerant that has exited the compressor 11 changes sequentially as indicated by 7-8-9-10. For this refrigeration cycle, the solid line in FIG. 6 is a Mollier diagram showing the flow of the refrigerant of the conventional air conditioner described in the above publication shown in FIG.
[0006]
In FIG. 8, the high-temperature and high-pressure gas exiting the compressor 11 is condensed by the condenser 13 as shown in the Mollier diagram 1-2 and decompressed by the expansion device 14 at 2-3. The refrigerant flowing into the gas-liquid separator 18 at 3 in the Mollier diagram is separated into gas and liquid as indicated at 4 and 5. The gas is decompressed in the capillary tube 20 as shown in 5-6 through the bypass flow passage (the two-way valve 19 and the capillary tube 20 are connected in series), and flows into the suction-side pipe line of the compressor 11. The liquid is evaporated by the evaporator 15 as in 4-6, merges with the gas bypassed in 6 and returns to the compressor 11. The dryness of the two-phase refrigerant at 3 is about 0.2 and the refrigerant gas to liquid mass flow ratios are 20% and 80%. Therefore, the flow rate of the refrigerant in the evaporator 15 flowing through 4-6 is 80% of the total flow rate, and the pressure loss is reduced to about 60 to 70% as compared with the refrigeration cycle without the gas-liquid separator 18. In addition, although the refrigerant capacity is reduced, the enthalpy difference is increased because the degree of thirst at the inlet of the evaporator 15 is reduced by the gas-liquid separator 18, and the evaporation capacity is reduced with the evaporation capacity in the refrigeration cycle without the gas-liquid separator 18. They are almost equal. Therefore, the pressure loss of the evaporator 15 and the connection pipe on the low pressure side is reduced, so that the work of the compressor is reduced, and the operation efficiency (COP) of the refrigeration cycle is improved.
[0007]
However, in this conventional air conditioner, since the degree of dryness of the refrigerant that has flown indoors (the indoor heat exchanger 15) from the gas-liquid separator 18 during the cooling operation is small, compared to a refrigeration cycle without the gas-liquid separator 18. In addition, there is a problem that the ratio of the liquid refrigerant in the gas-liquid separator 18, the connection pipe, and the evaporator 15 increases, and the optimal amount of the enclosed refrigerant increases. This means that the liquid refrigerant stagnation amount in the outdoor unit at a low outdoor temperature increases, and the refrigerating machine oil dissolves in the refrigerant more, resulting in poor lubrication, and a load on the compressor 11 due to liquid compression at startup. As a result, the reliability of the compressor 11 is reduced. Further, an increase in the amount of the enclosed refrigerant is not preferable from the viewpoint of global environmental protection.
[0008]
The present invention has been made in view of the above, and an object of the present invention is to satisfy the reliability of a compressor by minimizing the optimal increase in the amount of charged refrigerant by attaching a gas-liquid separator as much as possible. Another object of the present invention is to provide an air conditioner with improved efficiency.
[0009]
[Means for Solving the Problems]
The above object is achieved by connecting a compressor, an operation switching valve connected to the compressor, an outdoor heat exchanger connected to the operation switching valve, a throttle device connected to the outdoor unit, and the throttle device. A gas-liquid separator, an indoor heat exchanger connected to the gas-liquid separator and the operation switching valve, a bypass line connecting the gas-liquid separator and a compressor suction line, and a bypass line In an air conditioner provided with a two-way valve provided on the way, when the outdoor heat exchanger acts as a condenser, the outlet pipe becomes one system in the outdoor heat exchanger. This is achieved by adopting a pipeline configuration.
[0010]
Further, the object is to provide a compressor, an operation switching valve connected to the compressor, an outdoor heat exchanger connected to the operation switching valve, a throttle device connected to the outdoor unit, and a connection of the throttle device. Gas-liquid separator, an indoor heat exchanger connected to the gas-liquid separator and the operation switching valve, a bypass line connecting the gas-liquid separator and a compressor suction line, and a bypass line In an air conditioner provided with a two-way valve provided in the middle of a path, when the outdoor heat exchanger acts as a condenser, by providing an auxiliary heat exchanger having a pipe at one outlet at the outlet thereof. Achieved.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to the system diagram of the air conditioner shown in FIG.
[0012]
In FIG. 8, reference numeral 11 denotes a compressor, 12 denotes a four-way valve which is an operation switching valve for switching between a cooling cycle and a heating cycle, 13 denotes an outdoor heat exchanger, and 14 denotes an electric expansion valve or the like which performs a throttling function during cooling operation and heating operation. The expansion device 15 is an indoor heat exchanger. Reference numeral 18 is a gas-liquid separator, 19 is a two-way valve that can be fully closed, and 20 is a decompression device such as a capillary tube. Reference numerals 19 and 20 denote electric expansion valves that can be fully closed, and can be substituted.
[0013]
These are sequentially connected by a refrigerant pipe to form a refrigeration cycle. However, the pipeline including 19 and 20 is a bypass pipeline connecting the gas-liquid separator 18 and the suction pipeline of the compressor 11.
[0014]
The operation of the air conditioner configured as described above will be described. During the cooling operation, the refrigerant flows in the direction of the solid arrow in FIG. The refrigerant compressed by the compressor 11 is condensed in the outdoor heat exchanger 13 and radiates heat to the air, is decompressed and expanded by the expansion device 14, and is separated into liquid and gas by the gas-liquid separator 18. The liquid refrigerant evaporates in the indoor heat exchanger 15, absorbs heat from the air and returns to the compressor 11, and the gas refrigerant opens the two-way valve 19, so that the capillary tube 20 prevents the liquid from returning to the compressor 11, thereby achieving optimal pressure reduction. The pressure is reduced by the amount and returned to the compressor.
[0015]
In the air conditioner that operates as described above, the pipe configuration of the outdoor heat exchanger 13 is compared between FIG. 1 and FIG. The refrigerant flows in the direction of the solid arrow. The flow is split into two systems at line 21, then four lines at lines 22 and 23, and again at two lines at line 24. FIG. 2 merges into one system after exiting the heat exchanger. FIG. 1 shows that the liquid refrigerant condensed in line 24 merges into one system at the lower part of the heat exchanger, so that the flow velocity increases and the heat transfer coefficient in the tube increases. And the supercooling degree is sufficiently higher than in FIG.
[0016]
A refrigeration cycle using an optimal amount of refrigerant without the gas-liquid separator 18 is shown by a broken line in the Mollier diagram in FIG. If the gas-liquid separator 18 is provided with the same refrigerant amount and the ratio of the liquid refrigerant to the indoor side is increased, even if the enthalpy difference on the evaporation side is widened by the gas-liquid separation cycle, the refrigerant flow rate is reduced. Insufficient refrigeration cycle will result and cooling capacity will decrease. For this reason, in the Mollier diagram, as shown by the solid line in FIG. 9, the condensing pressure and the degree of supercooling decrease, and the performance decreases. Therefore, it is necessary to increase the amount of the charged refrigerant.
[0017]
However, the increase in the amount of enclosed refrigerant is caused by the increase in the amount of liquid refrigerant retained in the outdoor unit at low outside temperatures, and the refrigerating machine oil is dissolved in the refrigerant, resulting in poor lubrication. The load on the compressor increases, leading to a decrease in the reliability of the compressor. Further, an increase in the amount of the enclosed refrigerant is not preferable from the viewpoint of global environmental protection. Therefore, the increase in the amount of the charged refrigerant can be suppressed by adopting the pipe configuration shown in FIG. 1 in which the degree of supercooling can be sufficiently obtained. For example, FIG. 10 shows a case of a separate room air conditioner having a rated cooling capacity of 2.8 kW. In the figure, the horizontal axis indicates the amount of added refrigerant, and the vertical axis indicates the operating efficiency (COP) improvement rate. The solid line 40 indicates the pipeline configuration in FIG. 1 and the broken line 41 indicates the pipeline configuration in FIG. From this graph, it can be seen that the operating efficiency (COP) improvement rate in the pipe configuration of FIG. 1 is the same even if the amount of refrigerant is about 50 g smaller than that of FIG.
[0018]
During the heating operation, the refrigerant flows in the direction of the dashed arrow in FIG. The two-way valve 19 closes. The refrigerant compressed in the compressor 11 is condensed in the indoor heat exchanger 15 and radiates heat to the air, decompressed and expanded by the expansion device 14, evaporated in the outdoor heat exchanger 13 to absorb heat from the air, and returned to the compressor 11. . At this time, the condensed liquid refrigerant stays inside the gas-liquid separator 18. In a room air conditioner or the like, the indoor heat exchanger is usually smaller than the outdoor heat exchanger, so the optimal refrigerant amount in the heating operation is smaller than that in the cooling operation. Therefore, by the gas-liquid separator 18 serving as a liquid receiver, the amount of refrigerant can be adjusted in the cooling operation and the heating operation, and the operation state can be optimized.
[0019]
In the air conditioner that operates as described above, the pipe configuration of the outdoor heat exchanger 13 is compared between FIG. 1 and FIG. The refrigerant flows in the direction of the dashed arrow. In FIG. 1, two systems of the pipeline 24 are provided from one system of the pipeline 25, and two systems of the pipeline 24 are provided at the entrance in FIG. Thereafter, four systems are provided by the pipes 22 and 23, and two systems are provided again by the pipe 21.
[0020]
Compared with the pipeline configuration of FIG. 2, the pipeline configuration of FIG. 1 has one pipeline at the inlet, so that the pressure loss of the gas refrigerant increases. However, since the outdoor heat exchanger 13 is sufficiently large as compared with the one-system pipe and the dryness of the two-phase refrigerant at the inlet is small, the influence of the pressure loss is reduced, and the refrigerant amount is optimally adjusted by the gas-liquid separator 18. There is almost no problem in performance degradation due to adjustment.
[0021]
Therefore, by adopting the pipe configuration shown in FIG. 1, it is possible to minimize the increase in the optimal amount of the charged refrigerant by attaching the gas-liquid separator during the cooling operation without reducing the performance during the heating operation.
[0022]
In the present embodiment, the pipe configuration of the outdoor heat exchanger 13 is the inlet pipe at the time of the cooling operation as shown in FIG. 1 as the four pipes of the pipe 22 and the pipe 23, but as shown in FIG. In this case, the inlet line is made up of two lines of line 27, and the outlet line 28 is made up of one line. As shown in FIG. May be one system.
[0023]
Next, a second embodiment of the present invention will be described with reference to the drawings. The system diagram of the air conditioner of the present embodiment is the same as that of the first embodiment. FIG. 5 shows another example of the specific configuration of the outdoor heat exchanger according to the present invention.
[0024]
During the cooling operation, the refrigerant flows in the direction of the solid arrow in FIG. The flow is split into two systems at line 21, then four lines at lines 22 and 23, and again at two lines at line 24. Thereafter, the liquid refrigerant condensed in the pipe 24 is combined into one system by the auxiliary heat exchanger 26, so that the flow rate increases, the heat transfer coefficient in the pipe increases, and a sufficient degree of supercooling is obtained. Compared with the first embodiment, one system pipe is a separate auxiliary heat exchanger, so that the pipe of the outdoor heat exchanger 13 and the heat transfer tube can be different. For example, if the tube diameter of the auxiliary heat exchanger is reduced, the heat transfer coefficient in the tube is further increased and a supercooling degree can be obtained, so that an increase in the amount of the enclosed refrigerant during the cooling operation can be suppressed.
[0025]
During the heating operation, the refrigerant flows in the direction of the dashed arrow in FIG. The stream forms one system of the auxiliary heat exchanger 26 at the inlet. After that, the system passes through the two pipelines 24 to become four systems in the pipelines 22 and 23, and the pipeline 21 becomes two systems again. Since the auxiliary heat exchanger is a single system, the pressure loss of the gas refrigerant increases. However, since the outdoor heat exchanger 13 is sufficiently large as compared with the one-system pipe and the dryness of the two-phase refrigerant at the inlet is small, the influence of the pressure loss is reduced, and the refrigerant amount is optimally adjusted by the gas-liquid separator 18. There is almost no problem in performance degradation due to adjustment.
[0026]
Therefore, by adopting the pipe configuration shown in FIG. 5, it is possible to minimize the increase in the optimal amount of the charged refrigerant due to the addition of the gas-liquid separator during the cooling operation without deteriorating the performance during the heating operation.
[0027]
【The invention's effect】
As is clear from the above embodiments, according to the present invention, when the outdoor heat exchanger acts as a condenser, the pipe configuration such that the pipe at the outlet becomes one system, or the pipe is By installing an auxiliary heat exchanger that is a single system, the optimal increase in the amount of charged refrigerant due to the addition of a gas-liquid separator can be minimized as much as possible, improving efficiency while satisfying compressor reliability. Can be done.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a pipe of an outdoor heat exchanger according to a first embodiment of the present invention.
FIG. 2 is a configuration diagram of a pipe of the outdoor heat exchanger according to the first embodiment of the present invention.
FIG. 3 is a configuration diagram of a pipe of the outdoor heat exchanger according to the first embodiment of the present invention.
FIG. 4 is a configuration diagram of a pipe of the outdoor heat exchanger according to the first embodiment of the present invention.
FIG. 5 is a configuration diagram of a pipe of an outdoor heat exchanger according to a second embodiment of the present invention.
FIG. 6 is a Mollier diagram showing operations in a gas-liquid separation cycle and a normal cycle.
FIG. 7 is a system diagram of an air conditioner without a gas-liquid separator.
FIG. 8 is a system diagram of an air conditioner having a gas-liquid separator.
FIG. 9 is a Mollier diagram showing an operation in the first embodiment of the present invention.
FIG. 10 is a diagram showing a relationship between a refrigerant addition amount and a COP efficiency improvement rate in the first embodiment of the present invention.
[Explanation of symbols]
11: compressor, 12: four-way valve, 13: outdoor heat exchanger, 14: throttle device, 15: indoor heat exchanger, 18: gas-liquid separator, 19: two-way valve, 20: capillary tube.

Claims

A compressor, an operation switching valve connected to the compressor, an outdoor heat exchanger connected to the operation switching valve, a restrictor connected to the outdoor unit, and a gas-liquid separator connected to the restrictor An indoor heat exchanger connected to the gas-liquid separator and the operation switching valve; a bypass line connecting the gas-liquid separator and the compressor suction line; and a midway portion of the bypass line. In the air conditioner provided with a two-way valve, when the outdoor heat exchanger acts as a condenser, a pipe configuration such that an outlet pipe becomes one system in the outdoor heat exchanger. Air conditioner.

A compressor, an operation switching valve connected to the compressor, an outdoor heat exchanger connected to the operation switching valve, a restrictor connected to the outdoor unit, and a gas-liquid separator connected to the restrictor An indoor heat exchanger connected to the gas-liquid separator and the operation switching valve; a bypass line connecting the gas-liquid separator and the compressor suction line; and a midway portion of the bypass line. An air conditioner provided with a two-way valve, wherein when the outdoor heat exchanger acts as a condenser, an auxiliary heat exchanger having a single conduit at an outlet thereof is provided.