JP5990972B2

JP5990972B2 - Air conditioner

Info

Publication number: JP5990972B2
Application number: JP2012075158A
Authority: JP
Inventors: 雅恵笹野
Original assignee: Fujitsu General Ltd
Current assignee: Fujitsu General Ltd
Priority date: 2012-03-28
Filing date: 2012-03-28
Publication date: 2016-09-14
Anticipated expiration: 2032-03-28
Also published as: JP2013204936A

Description

本発明は、混合冷媒を用いた空気調和機に関するものである。 The present invention relates to an air conditioner using a mixed refrigerant.

現在、空気調和機には冷媒としてＲ４１０ＡやＲ４０７Ｃが主に使われている。これらの冷媒はオゾン破壊係数（ＯＤＰ）が０であるが地球温暖化係数（＝ＧＷＰ）が高く（Ｒ４１０ＡのＧＷＰ＝２０９０、Ｒ４０７ＣのＧＷＰ＝１７７０）、地球温暖化防止の観点からＧＷＰの低い冷媒への置き換えが検討されている。ＧＷＰの低い冷媒の候補として挙げられている冷媒としては、ＨＦＣ系ではＲ３２（ＧＷＰ＝６７５）やＲ１２３４ｙｆ（ＧＷＰ＝４）、自然系冷媒ではプロパン（ＧＷＰ＝３）などがある。 Currently, R410A and R407C are mainly used as refrigerants in air conditioners. These refrigerants have an ozone depletion potential (ODP) of 0 but a high global warming potential (= GWP) (GWP of R410A = 2090, GWP = 1770 of R407C) and low GWP from the viewpoint of preventing global warming. A replacement with is being considered. Refrigerants listed as candidates for low GWP refrigerants include R32 (GWP = 675) and R1234yf (GWP = 4) in the HFC system, and propane (GWP = 3) in the natural refrigerant.

このうちＲ１２３４ｙｆは、圧力が低く定置用空調機用途では性能が悪いために製品の大型化が必要になり、従来機器と同仕様の製品設計は難しい。また、自然系冷媒は冷媒としての性能は良いが、強燃性のために製品に封入できる冷媒量がＩＥＣ規格により制限されており、一部の小型の空気調和機にしか適用できない。 Among these, R1234yf has a low pressure and has poor performance in stationary air conditioner applications, so it is necessary to increase the size of the product, and product design with the same specifications as conventional devices is difficult. Although natural refrigerants have good performance as refrigerants, the amount of refrigerant that can be enclosed in products is limited by the IEC standards due to their strong flammability, and can only be applied to some small air conditioners.

一方、Ｒ３２は、Ｒ４１０Ａの５０ｗｔ％を占める成分で冷媒の性能としてはＲ４１０Ａよりも良い。また微燃性冷媒だが、機器側で所定の防爆対応を行なえば適用できる可能性がある。しかし、Ｒ４１０Ａに比べ同一凝縮温度での圧力が若干高く、また吐出温度が上がりやすい特性を持つ。そのため従来のＲ４１０Ａ用機器に単独で適用しようとすると設計圧力の変更や吐出温度上昇への対応など、若干の設計変更が必要になる。 On the other hand, R32 is a component that occupies 50 wt% of R410A, and has a better refrigerant performance than R410A. Although it is a slightly flammable refrigerant, there is a possibility that it can be applied if a predetermined explosion-proof measure is taken on the device side. However, the pressure at the same condensation temperature is slightly higher than that of R410A, and the discharge temperature tends to rise. Therefore, if it is intended to be applied alone to the conventional R410A device, some design changes such as a change in the design pressure and a response to a rise in the discharge temperature are required.

このように、低ＧＷＰ冷媒の候補のうち、単一の冷媒で従来のＲ４１０Ａ機器の置き換えとなりうるものが存在しないことから、いくつかの冷媒を適当な割合で混合してそれぞれの問題を解決する方法が提案されている。例えば、性能は良いが同一凝縮温度での圧力の高いＲ３２と性能は劣るが同一凝縮温度での圧力の低いＲ１２３４ｙｆ、または、これと圧力−温度特性の似たＲ１３４ａの組み合わせなどが知られている。しかし、Ｒ３２とＲ１２３４ｙｆまたはＲ１３４ａは沸点が大きく異なるため（Ｒ３２：−５１．７℃、Ｒ１２３４ｙｆ：−２９．５℃、Ｒ１３４ａ：−２６．１℃）、これらの冷媒を混合すると温度勾配が発生し、制御しづらい、性能が出にくいなどの問題がある。 Thus, there is no single low refrigerant candidate that can replace the conventional R410A device among the low GWP refrigerant candidates, so that several refrigerants are mixed at an appropriate ratio to solve each problem. A method has been proposed. For example, R32 having good performance but high pressure at the same condensation temperature and R1234yf having low performance but low pressure at the same condensation temperature, or a combination of this and R134a having similar pressure-temperature characteristics are known. . However, since the boiling points of R32 and R1234yf or R134a are greatly different (R32: −51.7 ° C., R1234yf: −29.5 ° C., R134a: −26.1 ° C.), a temperature gradient is generated when these refrigerants are mixed. There are problems such as difficulty in controlling and difficulty in performance.

こうした混合冷媒を用いた空気調和機に関して、本発明者は既に特願２０１１−１０５５５６および特願２０１１−１０５５５７に示される空気調和機を提案している。図３に示すように、この空気調和機の冷凍サイクル回路は、圧縮機１２と、凝縮器（室外機）１４と、減圧手段１６と、蒸発器（室内機）１８と、四方弁２０とからなる。作動冷媒としては、Ｒ３２とＲ１３４ａのみ、または、Ｒ３２とＲ１２３４ｙｆのみからなる混合冷媒を用いる。 Regarding the air conditioner using such a mixed refrigerant, the present inventor has already proposed the air conditioners shown in Japanese Patent Application Nos. 2011-105556 and 2011-105557. As shown in FIG. 3, the refrigeration cycle circuit of the air conditioner includes a compressor 12, a condenser (outdoor unit) 14, a decompression unit 16, an evaporator (indoor unit) 18, and a four-way valve 20. Become. As the working refrigerant, a mixed refrigerant consisting of only R32 and R134a or only R32 and R1234yf is used.

圧縮機１２からの混合冷媒は、配管２６を通って第一凝縮器１４ａに入り、気液分離器２２で気液に分離される。気液分離器２２に溜まったＲ１３４ａ（またはＲ１２３４ｙｆ）リッチな液冷媒は、流量調整弁２４を通って配管３２で圧縮機１２にインジェクションされる。一方、気液分離器２２で分離された飽和蒸気冷媒は第二凝縮器１４ｂから配管２８および減圧手段１６を通って蒸発器１８に入る。この蒸発器１８に入る冷媒としてはＲ３２の割合が多くなる。蒸発器１８からの冷媒は配管３０を通じて圧縮機１２に送られる。 The mixed refrigerant from the compressor 12 enters the first condenser 14 a through the pipe 26 and is separated into gas and liquid by the gas-liquid separator 22. The R134a (or R1234yf) rich liquid refrigerant accumulated in the gas-liquid separator 22 is injected into the compressor 12 through the flow rate adjustment valve 24 and through the pipe 32. On the other hand, the saturated vapor refrigerant separated by the gas-liquid separator 22 enters the evaporator 18 from the second condenser 14 b through the pipe 28 and the decompression means 16. The ratio of R32 as the refrigerant entering the evaporator 18 is increased. The refrigerant from the evaporator 18 is sent to the compressor 12 through the pipe 30.

ここで、気液分離器２２が凝縮器１４の容積比Ａ％：（１００−Ａ）％となる位置に取り付けてあり、これにより凝縮器１４は凝縮器全体に対する容積割合がＡ％の第一凝縮器１４ａと（１００−Ａ）％の第二凝縮器１４ｂとで構成されることになる。気液分離器２２の取り付け位置としては、想定される運転条件下で冷媒が二相域にある位置を選定する必要がある。Ｒ３２とＲ１３４ａのみからなる混合冷媒でＲ３２の混合割合が８０ｗｔ％の場合を例とする。凝縮温度６８℃で運転するときに吐出温度が従来冷媒のＲ４１０Ａを使った機器と同じ９０℃になるように液インジェクションを制御し、また凝縮器出口での過冷却度が一般的な冷凍サイクルと同じ５ｄｅｇになるように冷凍サイクル全体を制御すると、図４に示すように、凝縮器で冷媒が放出するエネルギーの割合はガス域：２４％、二相域：６９％、過冷却域：７％となる。凝縮器の単位容積あたりの熱交換量は概ね一様とみなせるので、上述した熱交換器の容積割合よりＡを決めるとＡの値は２４〜９３％の範囲になる。 Here, the gas-liquid separator 22 is attached at a position where the volume ratio A% :( 100−A)% of the condenser 14 is obtained, whereby the condenser 14 has a first volume ratio of A% with respect to the whole condenser. The condenser 14a and the (100-A)% second condenser 14b are configured. As the attachment position of the gas-liquid separator 22, it is necessary to select a position where the refrigerant is in the two-phase region under the assumed operation conditions. An example is a case where a mixed refrigerant composed of only R32 and R134a and the mixing ratio of R32 is 80 wt%. When operating at a condensing temperature of 68 ° C, the liquid injection is controlled so that the discharge temperature is 90 ° C, which is the same as the equipment using the conventional refrigerant R410A, and the degree of supercooling at the condenser outlet is a general refrigeration cycle. When the entire refrigeration cycle is controlled so as to be the same 5 deg, as shown in FIG. 4, the proportion of energy released by the refrigerant in the condenser is as follows: gas region: 24%, two-phase region: 69%, supercooling region: 7% It becomes. Since the heat exchange amount per unit volume of the condenser can be regarded as substantially uniform, when A is determined from the volume ratio of the heat exchanger described above, the value of A is in the range of 24 to 93%.

なお凝縮器を通過する混合冷媒は、沸点の高い冷媒の方が先に液化する。ここで図５は、図４における二相域の冷媒内の液相冷媒の組成を示すものであり、二相域のうち凝縮器の入口側に近い方が、高沸点冷媒の割合が多くなることを示している。よって、二相域にあるＢ区間（図４参照）の液を取り出す際には、上記Ａを凝縮器の入口側に配置することが望ましい。 In addition, the mixed refrigerant passing through the condenser is liquefied first in the refrigerant having a higher boiling point. Here, FIG. 5 shows the composition of the liquid-phase refrigerant in the refrigerant in the two-phase region in FIG. 4, and the proportion of the high-boiling refrigerant increases in the two-phase region closer to the inlet side of the condenser. It is shown that. Therefore, when taking out the liquid of B section (refer FIG. 4) in a two-phase area | region, it is desirable to arrange | position said A to the inlet side of a condenser.

このように、二相域から先に液化しやすいＲ１３４ａ（またはＲ１２３４ｙｆ）の液冷媒を予め分離することで、蒸発器１８に回る冷媒のうちＲ３２の割合がより大きくなり、蒸発器１８での温度勾配を小さくすることができる。 Thus, by separating in advance the liquid refrigerant of R134a (or R1234yf) that is liable to liquefy first from the two-phase region, the ratio of R32 in the refrigerant that goes to the evaporator 18 becomes larger, and the temperature at the evaporator 18 The gradient can be reduced.

一方、圧縮機１２にインジェクションされた冷媒は液状態のため、それが気化する熱により最終的に吐出される冷媒の温度を抑制することができる。さらにこの液冷媒はＲ３２に比べて断熱圧縮指数の小さいＲ１３４ａ（またはＲ１２３４ｙｆ）の割合が大きいので、Ｒ１３４ａ（またはＲ１２３４ｙｆ）の割合が小さい液冷媒をインジェクションするよりも大きな吐出温度抑制効果を持つ。このため、非共沸混合冷媒の持つ短所の影響を小さくすると同時に、その主成分であるＲ３２に起因する短所の影響も小さくすることができる。 On the other hand, since the refrigerant injected into the compressor 12 is in a liquid state, the temperature of the refrigerant finally discharged can be suppressed by the heat that it vaporizes. Furthermore, since this liquid refrigerant has a larger ratio of R134a (or R1234yf) having a smaller adiabatic compression index than R32, the liquid refrigerant has a larger discharge temperature suppression effect than injection of a liquid refrigerant having a smaller ratio of R134a (or R1234yf). For this reason, it is possible to reduce the influence of the disadvantages of the non-azeotropic refrigerant mixture and to reduce the influence of the disadvantages due to R32 as the main component.

ところで、上記の従来の混合冷媒を用いた空気調和機において、温度勾配による蒸発器の性能低下と運転中の吐出温度過昇とを防止するとともに、冷房・暖房ともに使用することが可能な運転温度範囲の広い空気調和機の開発が望まれていた。 By the way, in the above-described conventional air conditioner using a mixed refrigerant, an operating temperature that can be used for both cooling and heating as well as preventing deterioration in the performance of the evaporator due to a temperature gradient and excessive discharge temperature during operation. The development of a wide range of air conditioners has been desired.

本発明は、上記に鑑みてなされたものであって、混合冷媒を用いた空気調和機において、温度勾配による蒸発器の性能低下と運転中の吐出温度過昇とを防止するとともに、冷房・暖房ともに使用することが可能な運転温度範囲の広い空気調和機を提供することを目的とする。 The present invention has been made in view of the above, and in an air conditioner using a mixed refrigerant, prevents deterioration in the performance of the evaporator due to a temperature gradient and excessive discharge temperature during operation, and cooling and heating. An object is to provide an air conditioner with a wide operating temperature range that can be used together.

上記した課題を解決し、目的を達成するために、本発明の請求項１に係る空気調和機は、圧縮機、第一熱交換器、減圧手段、第二熱交換器を冷媒配管で接続して形成した冷媒回路に、第一の冷媒であるＲ３２を第二の冷媒であるＲ１３４ａまたはＲ１２３４ｙｆより大きい混合比で混合した２種混合冷媒を流通させ、冷房運転と暖房運転とに切換可能な空気調和機であって、前記冷媒回路は、冷房運転時において、凝縮器として機能する前記第一熱交換器の前記第二の冷媒が液リッチである位置から分岐した前記２種混合冷媒から気液分離器を介して分離した液冷媒を、前記圧縮機の中間圧にインジェクションする一方、暖房運転時において、凝縮器として機能する前記第二熱交換器と前記減圧手段との間に前記気液分離器が接続配置されるように回路を切り換える切換え弁を有することを特徴とする。 In order to solve the above-described problems and achieve the object, an air conditioner according to claim 1 of the present invention includes a compressor, a first heat exchanger, a decompression unit, and a second heat exchanger connected by a refrigerant pipe. Air that can be switched between a cooling operation and a heating operation by circulating a two-type mixed refrigerant in which R32, which is the first refrigerant, is mixed at a mixing ratio larger than R134a or R1234yf, which is the second refrigerant. In the air conditioner, the refrigerant circuit includes a gas-liquid from the two-type mixed refrigerant branched from a position where the second refrigerant of the first heat exchanger functioning as a condenser is liquid-rich during cooling operation. While the liquid refrigerant separated through the separator is injected into the intermediate pressure of the compressor, the gas-liquid separation is performed between the second heat exchanger functioning as a condenser and the pressure reducing means during heating operation. Connected And having a switching valve for switching the sea urchin circuit.

また、本発明の請求項２に係る空気調和機は、上述した請求項１において、前記第一の冷媒の混合比は８０〜９０ｗｔ％であることを特徴とする。 The air conditioner according to claim 2 of the present invention is characterized in that, in the above-described claim 1, the mixing ratio of the first refrigerant is 80 to 90 wt%.

また、本発明の請求項３に係る空気調和機は、上述した請求項１または２において、冷房運転時において、凝縮器として機能する前記第一熱交換器内の冷媒が気液二相状態となる位置から前記液冷媒を分離することを特徴とする。 The air conditioner according to claim 3 of the present invention is the air conditioner according to claim 1 or 2, wherein the refrigerant in the first heat exchanger functioning as a condenser is in a gas-liquid two-phase state in the cooling operation. The liquid refrigerant is separated from the position.

また、本発明の請求項４に係る空気調和機は、上述した請求項１〜３のいずれか一つにおいて、冷房運転時において、前記気液分離器の使用／不使用を切り換える切換え弁を有することを特徴とする。 Moreover, the air conditioner which concerns on Claim 4 of this invention has the switching valve which switches use / non-use of the said gas-liquid separator in the cooling operation in any one of Claims 1-3 mentioned above. It is characterized by that.

また、本発明の請求項５に係る空気調和機は、上述した請求項１〜４のいずれか一つにおいて、暖房運転時において、前記気液分離器の容器内の圧力を凝縮圧と蒸発圧の間の任意の値に制御するための絞り機構を、前記気液分離器の容器と凝縮器として機能する前記第二熱交換器との間に設けたことを特徴とする。 An air conditioner according to a fifth aspect of the present invention is the air conditioner according to any one of the first to fourth aspects, wherein during the heating operation, the pressure in the container of the gas-liquid separator is reduced to a condensation pressure and an evaporation pressure. A throttling mechanism for controlling to an arbitrary value between is provided between the container of the gas-liquid separator and the second heat exchanger functioning as a condenser.

本発明によれば、圧縮機、第一熱交換器、減圧手段、第二熱交換器を冷媒配管で接続して形成した冷媒回路に、第一の冷媒であるＲ３２を第二の冷媒であるＲ１３４ａまたはＲ１２３４ｙｆより大きい混合比で混合した２種混合冷媒を流通させ、冷房運転と暖房運転とに切換可能な空気調和機であって、前記冷媒回路は、冷房運転時において、凝縮器として機能する前記第一熱交換器の前記第二の冷媒が液リッチである位置から分岐した前記２種混合冷媒から気液分離器を介して分離した液冷媒を、前記圧縮機の中間圧にインジェクションする一方、暖房運転時において、凝縮器として機能する前記第二熱交換器と前記減圧手段との間に前記気液分離器が接続配置されるように回路を切り換える切換え弁を有する。 According to the present invention, R32 which is the first refrigerant is the second refrigerant in the refrigerant circuit formed by connecting the compressor, the first heat exchanger, the pressure reducing means, and the second heat exchanger with the refrigerant pipe. The air conditioner is capable of switching between a cooling operation and a heating operation by circulating a two-type mixed refrigerant mixed at a mixing ratio larger than R134a or R1234yf, and the refrigerant circuit functions as a condenser during the cooling operation. While the liquid refrigerant separated from the two-type mixed refrigerant branched from the position where the second refrigerant of the first heat exchanger is liquid-rich through a gas-liquid separator is injected into the intermediate pressure of the compressor And a switching valve for switching the circuit so that the gas-liquid separator is connected between the second heat exchanger functioning as a condenser and the pressure reducing means during heating operation.

このため、冷房運転時においては、二相域から先に液化しやすいＲ１３４ａ（またはＲ１２３４ｙｆ）リッチの液冷媒を予め分離することで、蒸発器として機能する第二熱交換器に回る冷媒のうちＲ３２の割合が大きくなり、蒸発器での温度勾配を小さくすることができる。また、圧縮機にインジェクションされた冷媒は液状態のため、それが気化する熱により最終的に吐出される冷媒の温度を抑制することができる。さらにこの液冷媒はＲ３２に比べて吐出温度が低い物性を持つＲ１３４ａ（またはＲ１２３４ｙｆ）を多く含むので、封入時の組成割合の液冷媒をインジェクションするよりも大きな吐出温度抑制効果を持つ。 For this reason, during the cooling operation, R32a (or R1234yf) rich liquid refrigerant, which is liable to be liquefied first from the two-phase region, is separated in advance, so that R32 out of the refrigerant circulating to the second heat exchanger functioning as an evaporator. And the temperature gradient in the evaporator can be reduced. Further, since the refrigerant injected into the compressor is in a liquid state, the temperature of the refrigerant finally discharged can be suppressed by the heat that it vaporizes. Further, since this liquid refrigerant contains a larger amount of R134a (or R1234yf) having a lower discharge temperature than R32, it has a larger discharge temperature suppression effect than injection of liquid refrigerant having a composition ratio at the time of encapsulation.

また、切換え弁の切り換えにより、第二熱交換器と減圧手段との間に気液分離器を接続配置することで、この空気調和機は暖房運転も行うことができる。したがって、温度勾配による蒸発器の性能低下と運転中の吐出温度過昇とを防止するとともに、冷房・暖房ともに使用することが可能な運転温度範囲の広い空気調和機を提供することができるという効果を奏する。 Moreover, this air conditioner can also perform heating operation by connecting and disposing a gas-liquid separator between the second heat exchanger and the pressure reducing means by switching the switching valve. Therefore, it is possible to provide an air conditioner with a wide operating temperature range that can be used for both cooling and heating, while preventing a decrease in the performance of the evaporator due to a temperature gradient and an excessive increase in the discharge temperature during operation. Play.

図１は、本発明に係る空気調和機の冷房運転時の冷媒回路図である。FIG. 1 is a refrigerant circuit diagram during cooling operation of the air conditioner according to the present invention. 図２は、本発明に係る空気調和機の暖房運転時の冷媒回路図である。FIG. 2 is a refrigerant circuit diagram during heating operation of the air conditioner according to the present invention. 図３は、従来の空気調和機の冷房運転時の冷媒回路図である。FIG. 3 is a refrigerant circuit diagram during cooling operation of a conventional air conditioner. 図４は、図１および図３の回路に関するｐ−ｈ線図である。FIG. 4 is a ph diagram for the circuits of FIGS. 図５は、凝縮温度６８℃を想定した場合の、凝縮器内の二相域における液冷媒（液相）の組成を示す図である。FIG. 5 is a diagram showing the composition of the liquid refrigerant (liquid phase) in the two-phase region in the condenser when a condensation temperature of 68 ° C. is assumed.

以下に、本発明に係る空気調和機の実施の形態を図面に基づいて詳細に説明する。なお、この実施例によりこの発明が限定されるものではない。 Embodiments of an air conditioner according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

本発明に係る空気調和機では、Ｒ３２にＲ１３４ａ、または、Ｒ３２にＲ１２３４ｙｆを混合した二成分の混合冷媒を用いる。このとき、Ｒ３２の混合割合は熱帯地域での冷房運転を想定し、凝縮温度６５〜６８℃での圧力がＲ４１０Ａの設計圧力（４．１５ＭＰａＧ）未満となるように８０〜９０ｗｔ％とする。以下の説明では、例としてＲ３２とＲ１３４ａをそれぞれ８０ｗｔ％、２０ｗｔ％の割合で混合した冷媒を、蒸発温度１５℃／凝縮温度６８℃の条件で運転した場合を想定する。ここで、混合冷媒の二つの成分は沸点が異なるために凝縮および蒸発過程において温度勾配が発生する。蒸発器における温度勾配は２．５度となる。 In the air conditioner according to the present invention, a two-component mixed refrigerant obtained by mixing R134a with R32 or R1234yf with R32 is used. At this time, the mixing ratio of R32 is assumed to be cooling operation in the tropical region, and is set to 80 to 90 wt% so that the pressure at the condensation temperature of 65 to 68 ° C. is less than the design pressure (4.15 MPaG) of R410A. In the following description, as an example, it is assumed that a refrigerant in which R32 and R134a are mixed at a ratio of 80 wt% and 20 wt%, respectively, is operated under the conditions of an evaporation temperature of 15 ° C./condensation temperature of 68 ° C. Here, since the two components of the mixed refrigerant have different boiling points, a temperature gradient is generated in the condensation and evaporation processes. The temperature gradient in the evaporator is 2.5 degrees.

また、Ｒ３２の混合割合が８０ｗｔ％以上の場合、温度勾配はＲ１３４ａの混合比が少なくなると小さくなるため、蒸発器に流入する冷媒はＲ１３４ａの割合が少ない方が望ましい。一方で、凝縮器での冷媒が凝縮する際には沸点の高いＲ１３４ａの方が先に凝縮する。すなわち、混合冷媒が凝縮している間（全体の乾き度が０〜１の間）の液冷媒成分には冷媒サイクル回路に封入時の冷媒組成の組成比より多い割合のＲ１３４ａ成分が含まれる（図５を参照）。凝縮器の途中から液冷媒の一部を分離することにより、蒸発器に流入する冷媒Ｒ１３４ａの割合を少なくできる。 In addition, when the mixing ratio of R32 is 80 wt% or more, the temperature gradient becomes smaller when the mixing ratio of R134a decreases, so that the refrigerant flowing into the evaporator preferably has a smaller ratio of R134a. On the other hand, when the refrigerant in the condenser condenses, R134a having a higher boiling point condenses first. That is, the liquid refrigerant component while the mixed refrigerant is condensed (the entire dryness is between 0 and 1) includes the R134a component in a proportion larger than the composition ratio of the refrigerant composition when sealed in the refrigerant cycle circuit ( (See FIG. 5). By separating a part of the liquid refrigerant from the middle of the condenser, the ratio of the refrigerant R134a flowing into the evaporator can be reduced.

Ｒ３２はＲ４１０Ａに比べて吐出温度が高い傾向を持つ。例えば、Ｒ３２だけを冷媒とする冷凍サイクルで蒸発温度１５℃／凝縮温度６８℃の条件で運転した場合を想定すると、吐出温度は１０４℃を越える（Ｒ４１０Ａの場合は約９０℃）。Ｒ１３４ａを２０ｗｔ％含んだ混合冷媒でも同じ条件での吐出温度は１００℃を越えるため、Ｒ４１０Ａを用いる空気調和機と同じ設計の冷媒サイクルでこの混合冷媒を使用するためには吐出温度を１０度ほど下げる必要がある。 R32 tends to have a higher discharge temperature than R410A. For example, assuming a case where the operation is performed under conditions of an evaporation temperature of 15 ° C./condensation temperature of 68 ° C. in a refrigeration cycle using only R32 as a refrigerant, the discharge temperature exceeds 104 ° C. (in the case of R410A, about 90 ° C.). Even in a mixed refrigerant containing 20 wt% of R134a, the discharge temperature under the same conditions exceeds 100 ° C. Therefore, in order to use this mixed refrigerant in the refrigerant cycle of the same design as the air conditioner using R410A, the discharge temperature is about 10 degrees. Need to lower.

次に、同じ冷媒で暖房運転も行う場合を考える。寒冷地での暖房運転を想定して蒸発温度−２５℃／凝縮温度３７℃とすると、Ｒ３２とＲ１３４ａのみからなる混合冷媒でＲ３２の混合割合が８０ｗｔ％の場合、理論上の吐出温度は約８６℃となる（Ｒ４１０Ａの場合は約６７℃）。但し、これは圧縮機内での損失を無視した値であり、実際の運転状態では吐出温度が１００℃を超える可能性もある。したがって、この冷媒を暖房運転に使う場合も、冷房と同様に吐出温度を下げる工夫が必要になる。 Next, consider a case where the heating operation is performed with the same refrigerant. Assuming a heating operation in a cold region and assuming an evaporation temperature of −25 ° C./condensation temperature of 37 ° C., when the mixing ratio of R32 is 80 wt% with a mixed refrigerant consisting only of R32 and R134a, the theoretical discharge temperature is about 86 (In the case of R410A, about 67 ° C.). However, this is a value ignoring the loss in the compressor, and the discharge temperature may exceed 100 ° C. in an actual operation state. Therefore, even when this refrigerant is used for heating operation, it is necessary to devise a technique for lowering the discharge temperature as in the case of cooling.

そこで、本発明に係る空気調和機の冷凍サイクル回路を、図１の冷房運転時の回路と、図２の暖房運転時の回路とに切り換え可能に構成する。以下、本発明の空気調和機を冷房運転時、暖房運転時とに分けて説明する。 Therefore, the refrigeration cycle circuit of the air conditioner according to the present invention is configured to be switchable between the circuit during the cooling operation of FIG. 1 and the circuit during the heating operation of FIG. Hereinafter, the air conditioner of the present invention will be described separately for cooling operation and heating operation.

［冷房運転時］
図１の冷媒回路図および図４のｐ−ｈ線図に示すように、本発明に係る空気調和機１０は、圧縮機１２と、第一熱交換器１４と、減圧手段１６と、第二熱交換器１８と、四方弁２０と、気液分離器２２と、切換え弁４４、４６、３６、３８とからなる。冷房運転時においては、第一熱交換器１４は凝縮器（室外機）として機能し、第二熱交換器１８は蒸発器（室内機）として機能する。 [During cooling operation]
As shown in the refrigerant circuit diagram of FIG. 1 and the ph diagram of FIG. 4, the air conditioner 10 according to the present invention includes a compressor 12, a first heat exchanger 14, a decompression means 16, a second The heat exchanger 18, the four-way valve 20, the gas-liquid separator 22, and the switching valves 44, 46, 36, and 38 are included. During the cooling operation, the first heat exchanger 14 functions as a condenser (outdoor unit), and the second heat exchanger 18 functions as an evaporator (indoor unit).

ここで、吐出温度の抑制のために、凝縮器（第一熱交換器１４）から分離した液冷媒を用いる。具体的には圧縮機１２の中間圧力部分に液冷媒を注入する。Ｒ１３４ａはＲ４１０Ａに比べて吐出温度が低い傾向を持つ。したがって、Ｒ１３４ａを多く含むＲ１３４ａリッチな液冷媒を圧縮機１２の中間圧に注入することにより、最終的な吐出温度を抑制することができる。 Here, the liquid refrigerant separated from the condenser (first heat exchanger 14) is used to suppress the discharge temperature. Specifically, liquid refrigerant is injected into the intermediate pressure portion of the compressor 12. R134a tends to have a lower discharge temperature than R410A. Therefore, the final discharge temperature can be suppressed by injecting the liquid refrigerant rich in R134a containing a large amount of R134a into the intermediate pressure of the compressor 12.

なお、従来技術として液冷媒を圧縮機に注入することが知られているが、それらの技術では冷媒の凝縮が完了し過冷却のとれた状態（凝縮器（第一熱交換器１４）出口〜減圧手段１６の手前）の冷媒を分離して注入している。しかし、本発明では、混合冷媒の成分が全て凝縮（全体の乾き度が０以下）してしまうとＲ３２とＲ１３４ａの組成比は冷媒サイクル回路に封入時の冷媒組成の組成比と同じになり、蒸発器（第二熱交換器１８）へ流入する冷媒の組成比を変えられない。したがって、圧縮機１２に注入するための液冷媒の分離は凝縮器（第一熱交換器１４）の二相域から行なう。気液分離器２２を用いて飽和液冷媒を取り出すことにより沸点の高い冷媒（Ｒ１３４ａ）をより多く液インジェクションにまわすことができる。 In addition, it is known as a prior art that liquid refrigerant is injected into a compressor. However, in those techniques, the refrigerant is completely condensed and supercooled (from the outlet of the condenser (first heat exchanger 14)). The refrigerant in front of the decompression means 16 is separated and injected. However, in the present invention, when all the components of the mixed refrigerant are condensed (the overall dryness is 0 or less), the composition ratio of R32 and R134a becomes the same as the composition ratio of the refrigerant composition when sealed in the refrigerant cycle circuit, The composition ratio of the refrigerant flowing into the evaporator (second heat exchanger 18) cannot be changed. Therefore, the liquid refrigerant for injection into the compressor 12 is separated from the two-phase region of the condenser (first heat exchanger 14). By taking out the saturated liquid refrigerant using the gas-liquid separator 22, a larger amount of refrigerant having a high boiling point (R134a) can be used for liquid injection.

より具体的には、気液分離器２２が凝縮器（第一熱交換器１４）の容積比Ａ％：（１００−Ａ）％となる位置に配管４０、４２を介して取り付けてあり、これにより凝縮器（第一熱交換器１４）は凝縮器全体に対する容積割合がＡ％の第一凝縮器１４ａと（１００−Ａ）％の第二凝縮器１４ｂとで構成されることになる。気液分離器２２の取り付け位置としては、想定される運転条件下で冷媒が二相域にある位置を選定する必要がある。 More specifically, the gas-liquid separator 22 is attached via piping 40 and 42 at a position where the volume ratio A% :( 100-A)% of the condenser (first heat exchanger 14) is obtained. Thus, the condenser (first heat exchanger 14) is composed of a first condenser 14a having a volume ratio of A% with respect to the whole condenser and a second condenser 14b having (100-A)%. As the attachment position of the gas-liquid separator 22, it is necessary to select a position where the refrigerant is in the two-phase region under the assumed operation conditions.

Ｒ３２とＲ１３４ａのみからなる混合冷媒でＲ３２の混合割合が８０ｗｔ％の場合、凝縮温度６８℃で運転するときに吐出温度が従来冷媒のＲ４１０Ａを使った機器と同じ９０℃になるように液インジェクションを制御し、また、凝縮器出口での過冷却度が一般的な冷凍サイクルと同じ５度になるように冷凍サイクル全体を制御すると、図４に示すように、凝縮器で冷媒が放出するエネルギーの割合はガス域：２４％、二相域：６９％、過冷却域：７％となる。凝縮器の単位容積あたりの熱交換量は概ね一様とみなせるので、上記放熱量の割合よりＡを決めるとＡの値は２４〜９３％の範囲になる。なお混合比によって冷媒の物性（上記放熱量の割合）が変わるため混合比に応じた位置を選定することが望ましい。 When the mixed ratio of R32 and R134a is Rwt and the mixing ratio of R32 is 80 wt%, liquid injection is performed so that the discharge temperature is 90 ° C, which is the same as the equipment using the conventional refrigerant R410A when operating at a condensation temperature of 68 ° C. If the overall refrigeration cycle is controlled so that the degree of supercooling at the outlet of the condenser is 5 degrees, which is the same as that of a typical refrigeration cycle, as shown in FIG. The ratio is 24% for the gas region, 69% for the two-phase region, and 7% for the supercooling region. Since the heat exchange amount per unit volume of the condenser can be regarded as almost uniform, if A is determined from the ratio of the heat radiation amount, the value of A is in the range of 24 to 93%. In addition, since the physical property of the refrigerant (the ratio of the heat release amount) varies depending on the mixing ratio, it is desirable to select a position corresponding to the mixing ratio.

なお、凝縮器（第一熱交換器１４）を通過する混合冷媒は、沸点の高い冷媒の方が先に液化する。ここで図５は、図４における二相域の冷媒内の液相冷媒の組成を示すものであり、二相域のうち凝縮器の入口側に近い方が、高沸点冷媒の割合が多くなることを示している。よって、二相域にあるＢ区間（図４参照）の液を取り出す際には、上記Ａを凝縮器の入口側に配置することが望ましい。 As for the mixed refrigerant passing through the condenser (first heat exchanger 14), the refrigerant having a higher boiling point is liquefied first. Here, FIG. 5 shows the composition of the liquid-phase refrigerant in the refrigerant in the two-phase region in FIG. 4, and the proportion of the high-boiling refrigerant increases in the two-phase region closer to the inlet side of the condenser. It is shown that. Therefore, when taking out the liquid of B section (refer FIG. 4) in a two-phase area | region, it is desirable to arrange | position said A to the inlet side of a condenser.

上記構成の動作を説明する。
圧縮機１２からの混合冷媒は、配管２６を通って第一凝縮器１４ａに入り、気液分離器２２で気液に分離される。気液分離器２２に溜まったＲ１３４ａリッチな液冷媒は、流量調整弁２４を通って配管３２で圧縮機１２にインジェクションされる。この流量調整弁２４は、前述したとおり、圧縮機１２より吐出される冷媒の温度に応じて制御され、これにより液インジェクション制御される。一方、気液分離器２２で分離された飽和蒸気冷媒は第二凝縮器１４ｂから減圧手段１６および配管５４、２８を通って蒸発器（第二熱交換器１８）に入る。この蒸発器に入る冷媒としてはＲ３２の割合が多くなる。蒸発器からの冷媒は配管３０を通じて圧縮機１２に送られる。 The operation of the above configuration will be described.
The mixed refrigerant from the compressor 12 enters the first condenser 14 a through the pipe 26 and is separated into gas and liquid by the gas-liquid separator 22. The R134a rich liquid refrigerant accumulated in the gas-liquid separator 22 is injected into the compressor 12 through the flow rate adjusting valve 24 and through the pipe 32. As described above, the flow rate adjusting valve 24 is controlled in accordance with the temperature of the refrigerant discharged from the compressor 12, and thereby liquid injection is controlled. On the other hand, the saturated vapor refrigerant separated by the gas-liquid separator 22 enters the evaporator (second heat exchanger 18) from the second condenser 14b through the decompression means 16 and the pipes 54 and 28. As a refrigerant entering this evaporator, the ratio of R32 increases. The refrigerant from the evaporator is sent to the compressor 12 through the pipe 30.

このように、二相域から先に液化しやすいＲ１３４ａの液冷媒を予め分離することで、蒸発器（第二熱交換器１８）に回る冷媒のうちＲ３２の割合がより大きくなり、蒸発器での温度勾配を小さくすることができる。 In this way, by separating the R134a liquid refrigerant that is liable to be liquefied first from the two-phase region in advance, the ratio of R32 in the refrigerant that goes to the evaporator (second heat exchanger 18) becomes larger. The temperature gradient can be reduced.

一方、圧縮機１２にインジェクションされた冷媒は液状態のため、それが気化する熱により最終的に吐出される冷媒の温度を抑制することができる。さらにこの液冷媒はＲ３２に比べて断熱圧縮指数の小さいＲ１３４ａを多く含むので、Ｒ１３４ａを多く含まない液冷媒をインジェクションするよりも大きな吐出温度抑制効果を持つ。このため、本発明の空気調和機１０によれば、非共沸混合冷媒の持つ短所の影響を小さくすると同時に、その主成分であるＲ３２に起因する短所の影響も小さくすることができる。 On the other hand, since the refrigerant injected into the compressor 12 is in a liquid state, the temperature of the refrigerant finally discharged can be suppressed by the heat that it vaporizes. Further, since this liquid refrigerant contains a larger amount of R134a having a smaller adiabatic compression index than R32, it has a greater discharge temperature suppression effect than injection of a liquid refrigerant that does not contain much R134a. For this reason, according to the air conditioner 10 of the present invention, the influence of the disadvantages of the non-azeotropic refrigerant mixture can be reduced, and at the same time, the influence of the disadvantages caused by the main component R32 can be reduced.

ここで、気液分離器２２に流入する冷媒（二相）のうち、飽和蒸気冷媒は気液分離器から流出していくが、飽和液冷媒は外気温度が冷媒温度より低いためにガス化しない。したがって冷媒循環量が一定の状態では時間とともに気液分離器２２内に飽和液冷媒が蓄積されていくことになる。この場合、気液分離器２２の容器２２ａ内の液面の高さが増し、飽和蒸気状態の冷媒が取り出せなくなると凝縮性能が低下してしまうため、この液面高さは容器２２ａ内に挿入された出口管の下端部より低い位置を保つように制御する必要がある。 Here, of the refrigerant (two phases) flowing into the gas-liquid separator 22, the saturated vapor refrigerant flows out of the gas-liquid separator, but the saturated liquid refrigerant is not gasified because the outside air temperature is lower than the refrigerant temperature. . Therefore, when the refrigerant circulation amount is constant, the saturated liquid refrigerant is accumulated in the gas-liquid separator 22 with time. In this case, the liquid level in the container 22a of the gas-liquid separator 22 increases, and if the saturated vapor state refrigerant cannot be taken out, the condensing performance deteriorates. Therefore, the liquid level is inserted into the container 22a. It is necessary to control so as to keep the position lower than the lower end of the outlet pipe.

そこで、図１に示すように、凝縮器１４と気液分離器２２を接続する冷媒回路上にバイパス３４と切換え弁３６、３８を設けるとともに、容器２２ａ内に長さの異なる配管４０、４２を挿入し、空気調和機の運転中に必要に応じて気液分離器２２の使用／不使用を切換えられるようにしておく。この切換えの条件としては、例えば短い配管４２の下端の連通口４２ａより低い位置に図示しない液面検知センサを設け、このセンサで検知される容器２２ａ内の液面が所定の高さを上回るか否かによって定めてもよい。 Therefore, as shown in FIG. 1, a bypass 34 and switching valves 36 and 38 are provided on the refrigerant circuit connecting the condenser 14 and the gas-liquid separator 22, and pipes 40 and 42 having different lengths are provided in the container 22a. It is inserted so that the use / nonuse of the gas-liquid separator 22 can be switched as necessary during operation of the air conditioner. As a condition for this switching, for example, a liquid level detection sensor (not shown) is provided at a position lower than the communication port 42a at the lower end of the short pipe 42, and whether the liquid level in the container 22a detected by this sensor exceeds a predetermined height. It may be determined depending on whether or not.

この場合、検知液面が所定の高さを下回る通常時においては、液冷媒の貯留量は許容範囲内であるので、切換え弁３６、３８の状態を、第一凝縮器１４ａと配管４０、第二凝縮器１４ｂと配管４２をそれぞれ連通し、バイパス３４を遮断するようにしておく。これにより、気液分離器２２は使用状態となり、第一凝縮器１４ａからの二相冷媒は配管４０を介して気液分離器２２に流入し、容器２２ａに溜まった冷媒は配管３２を通じて液インジェクションに使われる。 In this case, at a normal time when the detected liquid level is lower than a predetermined height, the amount of liquid refrigerant stored is within an allowable range, so that the state of the switching valves 36 and 38 is changed to the first condenser 14a, the piping 40, the first The two condensers 14b and the pipe 42 are communicated with each other so that the bypass 34 is shut off. As a result, the gas-liquid separator 22 is in use, the two-phase refrigerant from the first condenser 14a flows into the gas-liquid separator 22 via the pipe 40, and the refrigerant accumulated in the container 22a is liquid-injected through the pipe 32. Used for.

一方、検知液面が所定の高さを上回った時には、液冷媒の貯留量は過剰であることから、第一凝縮器１４ａとバイパス３４と第二凝縮器１４ｂとを連通し、第一凝縮器１４ａと配管４０、第二凝縮器１４ｂと配管４２の連通をそれぞれ遮断するように切換え弁３６、３８を切り換える。これにより、気液分離器２２は不使用状態とされ、第一凝縮器１４ａからの二相冷媒は気液分離器２２に流入しないでそのままバイパスを通り第二凝縮器１４ｂへ流入する。これにより、第二凝縮器１４ｂに液冷媒のみが流通することがなくなるので、この場合に比べ凝縮器１４全体としての凝縮能力の低下を避けることができる。なお、上記の液面検知センサの検知に基づく切換え弁３６、３８の切り換え制御は、図示しない制御手段により行うことができる。 On the other hand, when the detected liquid level exceeds a predetermined height, the storage amount of the liquid refrigerant is excessive, so that the first condenser 14a, the bypass 34, and the second condenser 14b are communicated with each other. The switching valves 36 and 38 are switched so that the communication between the pipe 14a and the pipe 40, and the communication between the second condenser 14b and the pipe 42 are cut off. As a result, the gas-liquid separator 22 is not used, and the two-phase refrigerant from the first condenser 14a does not flow into the gas-liquid separator 22 but flows directly into the second condenser 14b through the bypass. Thereby, since only a liquid refrigerant does not distribute | circulate through the 2nd condenser 14b, compared with this case, the fall of the condensing capability as the whole condenser 14 can be avoided. The switching control of the switching valves 36 and 38 based on the detection by the liquid level detection sensor can be performed by a control means (not shown).

［暖房運転時］
図２に示すように、同じ空気調和機１０で暖房運転を行う場合、第一熱交換器１４は蒸発器（室外機）として機能し、第二熱交換器１８は凝縮器（室内機）として機能する。蒸発過程の途中に気液分離器が存在すると、冷房時と同様に気液分離が行なわれるが、容器内の冷媒温度が周囲温度よりも低いために、分離された液の一部は容器内で蒸発する。一方、気液分離されてガスだけが蒸発器を流れる状態になると、性能が著しく低下するために容器から液冷媒を取り出したいが、冷媒循環量一定の条件で液冷媒だけを下流の蒸発器に流そうとすると時間と共に気液分離器内の飽和液冷媒は減少してしまう。したがって、暖房運転中は蒸発器（第一熱交換器１４）と気液分離器２２の間を前述の切換え弁３６、３８により遮断し、冷媒は常にバイパス３４を通るようにする。 [During heating operation]
As shown in FIG. 2, when heating operation is performed with the same air conditioner 10, the first heat exchanger 14 functions as an evaporator (outdoor unit), and the second heat exchanger 18 serves as a condenser (indoor unit). Function. If a gas-liquid separator is present during the evaporation process, gas-liquid separation is performed in the same way as during cooling. However, since the refrigerant temperature in the container is lower than the ambient temperature, a part of the separated liquid is contained in the container. Evaporate at. On the other hand, when gas and liquid are separated and only the gas flows through the evaporator, the performance is significantly reduced, so it is desired to take out the liquid refrigerant from the container, but only the liquid refrigerant is sent to the downstream evaporator under the condition that the refrigerant circulation amount is constant. If it tries to flow, the saturated liquid refrigerant in a gas-liquid separator will decrease with time. Therefore, during the heating operation, the gap between the evaporator (first heat exchanger 14) and the gas-liquid separator 22 is blocked by the aforementioned switching valves 36 and 38 so that the refrigerant always passes the bypass 34.

ここで、この気液分離器２２が暖房運転時の過冷却域（第二熱交換器１８出口と減圧手段１６の間）に挿入されるように冷凍サイクル回路を構成しておく。これにより、凝縮器（第二熱交換器１８）を出た液冷媒を従来と同様にして気液分離器２２の容器２２ａに溜めて液インジェクションに使うことができる。但し、この部分を接続する回路（凝縮器（第二熱交換器１８）〜気液分離器２２〜減圧手段１６）は冷房運転時には冷媒が通らないようにする必要があるため、切換え弁４４、４６により冷房運転時と暖房運転時とで冷媒回路を切り換える。 Here, the refrigeration cycle circuit is configured so that the gas-liquid separator 22 is inserted into a supercooling region (between the outlet of the second heat exchanger 18 and the decompression means 16) during heating operation. As a result, the liquid refrigerant exiting the condenser (second heat exchanger 18) can be stored in the container 22a of the gas-liquid separator 22 and used for liquid injection in the same manner as before. However, since the circuit (condenser (second heat exchanger 18) to gas-liquid separator 22 to decompression means 16) connecting these portions needs to prevent refrigerant from passing during the cooling operation, the switching valve 44, 46, the refrigerant circuit is switched between the cooling operation and the heating operation.

このとき、冷凍サイクル全体の減圧手段１６の他に凝縮器（第二熱交換器１８）と気液分離器２２の間に開度可変の絞り機構４８を設けておく。これら二つの減圧手段１６、絞り機構４８の組み合わせにより気液分離器２２の容器２２ａ内の圧力を蒸発圧〜凝縮圧の間で調節することができる。容器２２ａ内の液冷媒の割合は気液分離器２２内の圧力が高い時に多く、圧力が低い時に少なくなる。したがって、気液分離器２２内の圧力を調節することにより、結果として冷凍サイクル全体の冷媒分布を制御できる。 At this time, in addition to the decompression means 16 for the entire refrigeration cycle, a throttle mechanism 48 having a variable opening is provided between the condenser (second heat exchanger 18) and the gas-liquid separator 22. By the combination of these two decompression means 16 and the throttle mechanism 48, the pressure in the container 22a of the gas-liquid separator 22 can be adjusted between the evaporation pressure and the condensation pressure. The ratio of the liquid refrigerant in the container 22a increases when the pressure in the gas-liquid separator 22 is high, and decreases when the pressure is low. Therefore, adjusting the pressure in the gas-liquid separator 22 can control the refrigerant distribution of the entire refrigeration cycle as a result.

上記構成の動作を説明する。
圧縮機１２からの混合冷媒は、配管３０を通って凝縮器（第二熱交換器１８）に入り、配管２８、５０、絞り機構４８を介して配管４２から気液分離器２２に入って気液に分離される。気液分離器２２に溜まった液冷媒は、流量調整弁２４を通って配管３２で圧縮機１２にインジェクションされる一方で、配管４０、５２、減圧手段１６を通って蒸発器（第一熱交換器１４）に入り、その内部のバイパス３４を通過して配管２６を介して圧縮機１２に送られる。 The operation of the above configuration will be described.
The mixed refrigerant from the compressor 12 enters the condenser (second heat exchanger 18) through the pipe 30 and enters the gas-liquid separator 22 from the pipe 42 through the pipes 28 and 50 and the throttle mechanism 48. Separated into liquid. The liquid refrigerant accumulated in the gas-liquid separator 22 is injected into the compressor 12 through the flow rate adjusting valve 24 and through the pipe 32, while passing through the pipes 40 and 52 and the decompression means 16 to the evaporator (first heat exchange). 14), passes through the bypass 34 inside thereof, and is sent to the compressor 12 via the pipe 26.

ここで、気液分離器２２内の圧力の調節は、凝縮器（第二熱交換器１８）出口での過冷却度、および蒸発器（第一熱交換器１４）出口での過熱度を所定の値に保つことを目指すものである。最適な過冷却度および過熱度は、運転条件（空気温度や出そうとする能力）によって異なるために、運転条件に応じた目標過冷却度となるように上記絞り機構４８の開度を調節し、また、運転条件に応じた目標過熱度になるように減圧手段１６の開度を調節する。 Here, the pressure in the gas-liquid separator 22 is adjusted by setting the degree of supercooling at the outlet of the condenser (second heat exchanger 18) and the degree of superheating at the outlet of the evaporator (first heat exchanger 14). It aims to keep the value of. Since the optimum degree of supercooling and superheat varies depending on the operating conditions (air temperature and ability to output), the opening degree of the throttle mechanism 48 is adjusted so that the target supercooling degree according to the operating conditions is obtained. Moreover, the opening degree of the decompression means 16 is adjusted so that the target superheat degree according to the operating conditions is obtained.

また、容器２２ａ内で気液分離させることにより液相の冷媒は沸点の高い冷媒（Ｒ１３４ａ）が若干多い組成となるため、吐出温度を抑制する効果の高い冷媒が圧縮機１２にインジェクションされることになる。なお、気液分離器２２から蒸発器（第一熱交換器１４）に入る冷媒も液相から取り出されることになりＲ１３４ａが若干多い組成となるが、液インジェクションで冷媒循環量を増やすことにより暖房能力（凝縮熱量）の低下を抑えることができる。このように、本発明によれば、同じ気液分離器２２を冷房運転だけでなく暖房運転にも使用することで、運転温度範囲の広い空気調和機を提供することができる。 In addition, since the liquid-phase refrigerant has a composition with a little higher boiling point refrigerant (R134a) by gas-liquid separation in the container 22a, the refrigerant having a high effect of suppressing the discharge temperature is injected into the compressor 12. become. Note that the refrigerant entering the evaporator (first heat exchanger 14) from the gas-liquid separator 22 is also taken out of the liquid phase and has a slightly larger composition of R134a. However, heating is performed by increasing the refrigerant circulation rate by liquid injection. A decrease in ability (heat of condensation) can be suppressed. Thus, according to the present invention, an air conditioner having a wide operating temperature range can be provided by using the same gas-liquid separator 22 not only for cooling operation but also for heating operation.

以上説明したように、本発明に係る空気調和機によれば、圧縮機、第一熱交換器、減圧手段、第二熱交換器を冷媒配管で接続して形成した冷媒回路に、第一の冷媒であるＲ３２を第二の冷媒であるＲ１３４ａまたはＲ１２３４ｙｆより大きい混合比で混合した２種混合冷媒を流通させ、冷房運転と暖房運転とに切換可能な空気調和機であって、前記冷媒回路は、冷房運転時において、凝縮器として機能する前記第一熱交換器の前記第二の冷媒が液リッチである位置から分岐した前記２種混合冷媒から気液分離器を介して分離した液冷媒を、前記圧縮機の中間圧にインジェクションする一方、暖房運転時において、凝縮器として機能する前記第二熱交換器と前記減圧手段との間に前記気液分離器が接続配置されるように回路を切り換える切換え弁を有する。 As described above, according to the air conditioner according to the present invention, the refrigerant circuit formed by connecting the compressor, the first heat exchanger, the pressure reducing means, and the second heat exchanger with the refrigerant pipes has the first An air conditioner capable of switching between a cooling operation and a heating operation by circulating a two-type mixed refrigerant obtained by mixing R32 as a refrigerant at a mixing ratio larger than R134a or R1234yf as a second refrigerant, wherein the refrigerant circuit includes: In the cooling operation, the liquid refrigerant separated from the two-type mixed refrigerant branched from the position where the second refrigerant of the first heat exchanger functioning as a condenser is liquid-rich through a gas-liquid separator. The circuit is arranged such that the gas-liquid separator is connected between the second heat exchanger functioning as a condenser and the pressure reducing means during the heating operation while injecting the intermediate pressure of the compressor. Switching to switch Having.

このため、冷房運転時においては、二相域から先に液化しやすいＲ１３４ａ（またはＲ１２３４ｙｆ）リッチの液冷媒を予め分離することで、蒸発器として機能する第二熱交換器に循環する冷媒に含まれるＲ３２の割合が大きくなり、蒸発器での温度勾配を小さくすることができる。また、圧縮機にインジェクションされた冷媒は液状態のため、それが気化する熱により最終的に吐出される冷媒の温度を抑制することができる。さらにこの液冷媒はＲ３２に比べて断熱圧縮指数の小さい物性を持つＲ１３４ａ（またはＲ１２３４ｙｆ）を多く含むので、封入時の組成割合の液冷媒をインジェクションするよりも大きな吐出温度抑制効果を持つ。このため、非共沸混合冷媒の持つ短所の影響を小さくすることができると同時に、その主成分であるＲ３２に起因する短所の影響も小さくすることができる。 For this reason, during cooling operation, the R134a (or R1234yf) rich liquid refrigerant that is liable to liquefy first from the two-phase region is included in the refrigerant circulating in the second heat exchanger that functions as an evaporator by separating in advance. The ratio of R32 to be increased increases, and the temperature gradient in the evaporator can be reduced. Further, since the refrigerant injected into the compressor is in a liquid state, the temperature of the refrigerant finally discharged can be suppressed by the heat that it vaporizes. Further, since this liquid refrigerant contains a larger amount of R134a (or R1234yf) having a physical property with a smaller adiabatic compression index than R32, it has a larger discharge temperature suppression effect than injection of liquid refrigerant having a composition ratio at the time of encapsulation. For this reason, the influence of the disadvantages of the non-azeotropic refrigerant mixture can be reduced, and at the same time, the influence of the disadvantages caused by R32 as the main component can be reduced.

以上のように、本発明に係る空気調和機は、混合冷媒を用いた空気調和機に有用であり、特に、温度勾配による蒸発器の性能低下と運転中の吐出温度過昇とを防止するとともに、冷房・暖房ともに使用することが可能な運転温度範囲の広い空気調和機を提供するのに適している。 As described above, the air conditioner according to the present invention is useful for an air conditioner using a mixed refrigerant, and in particular, prevents deterioration in the performance of the evaporator due to a temperature gradient and excessive discharge temperature during operation. It is suitable for providing an air conditioner with a wide operating temperature range that can be used for both cooling and heating.

１０空気調和機
１２圧縮機
１４第一熱交換器（室外機）
１６減圧手段
１８第二熱交換器（室内機）
２０四方弁
２２気液分離器
２２ａ容器
２４流量調整弁
２６，２８，３０，３２，４０，４２，５０，５２，５４配管
３４バイパス
３６，３８，４４，４６切換え弁
４８絞り機構
10 Air Conditioner 12 Compressor 14 First Heat Exchanger (Outdoor Unit)
16 Pressure reducing means 18 Second heat exchanger (indoor unit)
20 Four-way valve 22 Gas-liquid separator 22a Container 24 Flow rate adjustment valve 26, 28, 30, 32, 40, 42, 50, 52, 54 Piping 34 Bypass 36, 38, 44, 46 Switching valve 48 Throttle mechanism

Claims

圧縮機、第一熱交換器、減圧手段、第二熱交換器を冷媒配管で接続して形成した冷媒回路に、第一の冷媒であるＲ３２を第二の冷媒であるＲ１３４ａまたはＲ１２３４ｙｆより大きい混合比で混合した２種混合冷媒を流通させ、冷房運転と暖房運転とに切換可能な空気調和機であって、
前記冷媒回路は、
冷房運転時において、凝縮器として機能する前記第一熱交換器の前記第二の冷媒が液リッチである位置から分岐した前記２種混合冷媒から気液分離器を介して分離した液冷媒を、前記圧縮機の中間圧にインジェクションする一方、
暖房運転時において、凝縮器として機能する前記第二熱交換器と前記減圧手段との間に前記気液分離器が接続配置されるように回路を切り換える切換え弁を有することを特徴とする空気調和機。 In the refrigerant circuit formed by connecting the compressor, the first heat exchanger, the decompression means, and the second heat exchanger with the refrigerant pipe, the first refrigerant R32 is mixed with the second refrigerant R134a or R1234yf. An air conditioner capable of switching between a cooling operation and a heating operation by circulating a two-type mixed refrigerant mixed at a ratio,
The refrigerant circuit is
During the cooling operation, the liquid refrigerant separated from the two-type mixed refrigerant branched from the position where the second refrigerant of the first heat exchanger functioning as a condenser is liquid rich via a gas-liquid separator, While injecting into the intermediate pressure of the compressor,
An air conditioner comprising a switching valve for switching a circuit so that the gas-liquid separator is connected and disposed between the second heat exchanger functioning as a condenser and the pressure reducing means during heating operation. Machine.

前記第一の冷媒の混合比は８０〜９０ｗｔ％であることを特徴とする請求項１に記載の空気調和機。 The air conditioner according to claim 1, wherein a mixing ratio of the first refrigerant is 80 to 90 wt%.

冷房運転時において、凝縮器として機能する前記第一熱交換器内の冷媒が気液二相状態となる位置から前記液冷媒を分離することを特徴とする請求項１または２に記載の空気調和機。 3. The air conditioning according to claim 1, wherein during the cooling operation, the liquid refrigerant is separated from a position where the refrigerant in the first heat exchanger functioning as a condenser is in a gas-liquid two-phase state. Machine.

冷房運転時において、前記気液分離器の使用／不使用を切り換える切換え弁を有することを特徴とする請求項１〜３のいずれか一つに記載の空気調和機。 The air conditioner according to any one of claims 1 to 3, further comprising a switching valve that switches use / nonuse of the gas-liquid separator during cooling operation.

暖房運転時において、前記気液分離器の容器内の圧力を凝縮圧と蒸発圧の間の任意の値に制御するための絞り機構を、前記気液分離器の容器と凝縮器として機能する前記第二熱交換器との間に設けたことを特徴とする請求項１〜４のいずれか一つに記載の空気調和機。 In the heating operation, the throttle mechanism for controlling the pressure in the gas-liquid separator container to an arbitrary value between the condensing pressure and the evaporation pressure functions as the gas-liquid separator container and the condenser. It provided between 2nd heat exchangers, The air conditioner as described in any one of Claims 1-4 characterized by the above-mentioned.