JP5696084B2 - Air conditioner - Google Patents
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- JP5696084B2 JP5696084B2 JP2012075400A JP2012075400A JP5696084B2 JP 5696084 B2 JP5696084 B2 JP 5696084B2 JP 2012075400 A JP2012075400 A JP 2012075400A JP 2012075400 A JP2012075400 A JP 2012075400A JP 5696084 B2 JP5696084 B2 JP 5696084B2
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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 air conditioning apparatus.
従来、空気調和装置を簡単に大容量化する方法として、室外機を複数台接続する方法が提案されており、現地での据付工事性を向上するために、各室外機の接続方法として均油管を用いない方式が種々提案されており、その１つの方法として特許文献１に記載の方法がある。 Conventionally, as a method of easily increasing the capacity of an air conditioner, a method of connecting a plurality of outdoor units has been proposed, and in order to improve the installation workability in the field, an oil equalizing pipe is used as a connection method of each outdoor unit. Various methods that do not use the method have been proposed, and one of the methods is described in Patent Document 1.
この従来技術のものは、圧縮機、油分離器、室外熱交換器、減圧装置、アキュムレータを有して成る室外機と、室内熱交換器と減圧装置を有して成る室内機を、それぞれ並列に複数台接続して成る空気調和装置において、前記アキュムレータ内に貯留される液量によってアキュムレータから流出する油循環量が可変可能となるようにアキュムレータ油流出調整手段と、前記アキュムレータと前記油分離器の下部とを接続するバイパス回路と、該バイパス回路にはバイパス回路を流れる油循環量が前記アキュムレータに貯留される液量の上限値と下限値で決定されるアキュムレータから流出する油循環量の上限値と下限値の間となるように調整する油循環量調整手段とを設けたことにより、アキュムレータと油分離器の下部とを接続するバイパス回路を流れる油循環量が、アキュムレータに貯留される液量の下限値で決定されるアキュムレータから流出する油循環量よりも多いため、油分離器内に余剰の冷凍機油が貯留されず、全ての余剰の冷凍機油はアキュムレータに貯留されることになり、各室外機に対して冷凍機油が不均一に戻される場合、各室外機でのアキュムレータに貯留される冷凍機油の量が可変し、アキュムレータに貯留される冷凍機油が上限値を越えた室外機からは冷凍機油が多く排出されるため冷凍機油が減った室外機に対して冷凍機油を供給することができ、均油管を用いなくても各室外機の油量を一定量以上確保することができ、現地での据付工事性を向上することができる。また、均油のために新たな冷媒回路を用いていないため、室外機の製造コストを安価に抑えることもできる。 In this prior art, a compressor, an oil separator, an outdoor heat exchanger, a pressure reducing device, an outdoor unit having an accumulator, and an indoor unit having an indoor heat exchanger and a pressure reducing device are arranged in parallel. A plurality of air conditioners connected to the accumulator, the accumulator oil outflow adjustment means, the accumulator and the oil separator so that the amount of oil circulation flowing out from the accumulator can be varied according to the amount of liquid stored in the accumulator A bypass circuit for connecting the lower part of the accumulator, and an upper limit of the oil circulation amount flowing out from the accumulator in which the oil circulation amount flowing in the bypass circuit is determined by an upper limit value and a lower limit value of the liquid amount stored in the accumulator By connecting the accumulator and the lower part of the oil separator by providing the oil circulation amount adjusting means for adjusting so that it is between the lower limit value and the lower limit value Since the amount of oil circulating through the circuit is larger than the amount of oil circulating out of the accumulator determined by the lower limit of the amount of liquid stored in the accumulator, excess refrigeration oil is not stored in the oil separator, Excess refrigeration oil will be stored in the accumulator, and if the refrigeration oil is returned unevenly to each outdoor unit, the amount of refrigerating machine oil stored in the accumulator in each outdoor unit will vary, and the accumulator will Refrigerating machine oil can be supplied to outdoor units with a reduced amount of refrigerating machine oil because much refrigerating machine oil is discharged from outdoor units where the stored refrigerating machine oil exceeds the upper limit. The amount of oil in the outdoor unit can be secured above a certain level, and on-site installation workability can be improved. In addition, since a new refrigerant circuit is not used for oil leveling, the manufacturing cost of the outdoor unit can be reduced.
上記特許文献１に記載のものは、複数台の室外機の均油方法として各室外機を接続する均油管を必要とせず均油のために新たな冷媒回路を用いていないため、現地での据付工事性の向上及び室外機の製造コストを安価にすることはできるが、アキュムレータから圧縮機に流出する油循環量に対しては考慮されていないため、アキュムレータから圧縮機に流出する油循環量が多くなると、油分離器で分離した油をアキュムレータに戻すバイパス回路を流れる油及び冷媒ガスの流量が増大し、圧縮機吸入冷媒のガス温度が上昇して冷媒密度が低下するため、圧縮機から流出する冷媒循環量が低下し性能が低下するという問題が生じる。 Since the thing of the said patent document 1 does not require the oil equalization pipe | tube which connects each outdoor unit as an oil equalization method of a plurality of outdoor units, and does not use a new refrigerant circuit for oil equalization, Although the installation workability can be improved and the manufacturing cost of the outdoor unit can be reduced, the amount of oil circulating from the accumulator to the compressor is not considered because the amount of oil circulating from the accumulator to the compressor is not considered. Increases the flow rate of the oil and refrigerant gas flowing through the bypass circuit that returns the oil separated by the oil separator to the accumulator, the gas temperature of the refrigerant sucked into the compressor rises, and the refrigerant density decreases. There arises a problem that the refrigerant circulation amount that flows out decreases and the performance decreases.
本発明の目的は、冷凍サイクル中への冷凍機油の流出を抑制すること又は均油管を用いずに室外機を複数台接続して成る空気調和装置の油分配性能を維持することができ、且つ空気調和装置としての性能を最大限に向上できる安価な空気調和装置を提供することである。
An object of the present invention, it is possible to maintain the oil distribution performance of the air conditioning apparatus formed by connecting multiple outdoor units without using the or oil equalizing tube to suppress the outflow of refrigeration oil into the refrigeration cycle, and An object is to provide an inexpensive air conditioner capable of maximizing the performance as an air conditioner.
上記の目的を達成するために本発明の空気調和装置では、圧縮機、油分離器、室外熱交換器、減圧装置、アキュムレータを有した室外機と、室内熱交換器と減圧装置を有した室内機を接続して成る空気調和装置において、前記アキュムレータには、油流量調整機構として容器内の導出管の下部に第１油戻し穴を形成し、前記第１油戻し穴によるかわき度をＸ１、第１油戻し穴径をｄ１、導出管内径をＤ、圧縮機最大油上がり率をα、アキュムレータ内冷媒溶解度をＣｒとした場合、ｄ１＝Ａ×（Ｄ）0.9、且つ０.１＜Ａ＜０.１６で、且つα＜（１−Ｘ１）×（１−Ｃｒ）となるように前記アキュムレータの導出管内径Ｄ、第１油戻し穴径ｄ１を設定すると共に、（返油回路を流れる油流量）≧（アキュムレータの第１油戻し穴で圧縮機に戻る油流量）となるように返油回路のキャピラリチューブの内径及び長さを設定し、余剰油が常にアキュムレータ内に貯留されるようにしたことを特徴とするものである。 In order to achieve the above object, in the air conditioner of the present invention, a compressor, an oil separator, an outdoor heat exchanger, a decompressor, an outdoor unit having an accumulator, an indoor heat exchanger and a decompressor In the air conditioner configured by connecting a machine, the accumulator is provided with a first oil return hole in the lower part of the outlet pipe in the container as an oil flow rate adjusting mechanism, and the degree of clearance by the first oil return hole is X1, When the first oil return hole diameter is d1, the outlet pipe inner diameter is D, the compressor maximum oil rise rate is α, and the refrigerant solubility in the accumulator is Cr, d1 = A × (D) 0.9 and 0.1 <A < The outlet pipe inner diameter D and the first oil return hole diameter d1 of the accumulator are set so that 0.16 and α <(1-X1) × (1-Cr) (the oil flowing through the oil return circuit) Flow rate) ≥ (Oil returning to the compressor at the first oil return hole of the accumulator Set the inner diameter and length of the capillary tube of an oil return circuit so that the amount), is characterized in that the excess oil is always to be stored in the accumulator.
また、上記のものにおいて、室外機及び室内機を複数台接続して成る空気調和装置のアキュムレータに第２の油流量調整機構として容器内の導出管の中部に第２油戻し穴を形成し、前記第２油戻し穴径ｄ２、導出管内径Ｄ、アキュムレータ内冷媒溶解度Ｃｒとした場合、ｄ２≦（（０.２５×（Ｄ）0.9）2−（ｄ１）2）0.5、且つ（返油量調整装置を流れる油循環量）＜（アキュムレータの第１油戻し穴と第２油戻し穴の両方で圧縮機に戻る油循環量）となるように第２油戻し穴径ｄ２の寸法を設定し、且つ第２油戻し穴の高さ位置から底面までのアキュムレータ内容積をＶＡ２、該空気調和装置に封入する油体積量をＶ０、圧縮機に保有される油体積量をＶＣ、アキュムレータ内冷媒溶解度をＣｒとした場合に、ＶＡ２＞（Ｖ０−ＶＣ）／（１−Ｃｒ）の関係が成り立つように前記第２油戻し穴の高さ位置を設定した構造が望ましい。 Further, in the above, a second oil return hole is formed in the middle of the outlet pipe in the container as a second oil flow rate adjustment mechanism in the accumulator of the air conditioner formed by connecting a plurality of outdoor units and indoor units, When the second oil return hole diameter d2, the outlet pipe inner diameter D, and the refrigerant solubility Cr in the accumulator, d2 ≦ ((0.25 × (D) 0.9 ) 2 − (d1) 2 ) 0.5 and (oil return amount) The size of the second oil return hole diameter d2 is set so that the amount of oil circulation flowing through the adjusting device) <(the amount of oil circulation returning to the compressor through both the first oil return hole and the second oil return hole of the accumulator). , The internal volume of the accumulator from the height position of the second oil return hole to the bottom surface is VA2, the volume of oil enclosed in the air conditioner is V0, the volume of oil held in the compressor is VC, the refrigerant solubility in the accumulator When Cr is Cr, VA2> (V0−VC) / A structure in which the height position of the second oil return hole is set so that the relationship (1-Cr) is established is desirable.
本発明によれば、余剰油が常にアキュムレータ内に貯留されるように返油量調整装置を流れる油流量を調整することで、以下に示すような効果がある。
（１）アキュムレータから圧縮機に流出する油循環量の最大値を抑制することにより、圧縮機吸入側の冷媒ガス過熱度が抑制されるため、圧縮機吸入側の冷媒ガス密度の低下を抑制することができ、同一周波数で運転される圧縮機から流出する冷媒量を多くすることができるため、該空気調和装置の能力を向上することができる。また、この能力向上分を圧縮機周波数を抑制するように制御すれば、運転周波数を下げることができるため、圧縮機への電気入力量が低減でき、この電気入力の低減分だけ省エネルギー性が向上する。
（２）また、余剰油を常にアキュムレータ内に貯留しているため、油分離器内を常に空の状態で使用するため、油分離器の分離効率を常に最大で使用することができ、冷凍サイクル内に流出する油量を低減することができる。更に油分離器に流入する油循環量は、アキュムレータから圧縮機に流出する油循環量と等しいことから、油分離器に流入する油循環量の最大値を抑制しているため、油分離器の分離効率が同等の場合でも、油分離器に流入する油循環量を低減しているため、更に冷凍サイクル内に流出する油量を低減でき、接続配管や熱交換器等での圧力損失が軽減され、且つ熱交換器の配管内に油膜が形成されにくいため熱交換効率も高くなり、冷凍サイクルの効率向上が可能となる。
According to the present invention, by adjusting the oil flow through the oil return quantity adjusting device so that excess Amaabura is stored at all times in the accumulator, there are the following effects.
(1) By suppressing the maximum value of the amount of circulating oil flowing out from the accumulator to the compressor, the degree of refrigerant gas superheating on the compressor suction side is suppressed, so that a decrease in refrigerant gas density on the compressor suction side is suppressed. Since the amount of refrigerant flowing out from the compressor operated at the same frequency can be increased, the capacity of the air conditioner can be improved. Also, if this capacity improvement is controlled so as to suppress the compressor frequency, the operating frequency can be lowered, so the amount of electrical input to the compressor can be reduced, and energy saving is improved by this reduction in electrical input. To do.
(2) Since the excess oil is always stored in the accumulator, the oil separator is always used in an empty state, so that the separation efficiency of the oil separator can always be used at the maximum, and the refrigeration cycle The amount of oil flowing out into the inside can be reduced. Furthermore, since the amount of oil circulation flowing into the oil separator is equal to the amount of oil circulation flowing out of the accumulator to the compressor, the maximum value of the oil circulation amount flowing into the oil separator is suppressed. Even when the separation efficiency is the same, the amount of oil circulating into the oil separator is reduced, so the amount of oil flowing out into the refrigeration cycle can be further reduced, and pressure loss in connecting pipes and heat exchangers is reduced. In addition, since an oil film is not easily formed in the pipe of the heat exchanger, the heat exchange efficiency is increased, and the efficiency of the refrigeration cycle can be improved.
また、本発明によれば、室外機及び室内機を複数台接続して成る空気調和装置のアキュムレータに第２の油流量調整機構として容器内の導出管の中部に第２油戻し穴を形成し、前記第２油戻し穴径をｄ２、導出管内径をＤ、アキュムレータ内冷媒溶解度をＣｒとした場合、ｄ２≦（（０.２５×（Ｄ）0.9）2−（ｄ１）2）0.5、且つ（返油回路を流れる油流量）＜（アキュムレータの第１油戻し穴と第２油戻し穴の両方で圧縮機に戻る油流量）となるように第２油戻し穴径ｄ２の寸法を設定し、且つ第２油戻し穴の高さ位置から底面までのアキュムレータ内容積をＶＡ２、該空気調和装置に封入する油体積量をＶ０、圧縮機に保有される油体積量をＶＣ、アキュムレータ内冷媒溶解度をＣｒとした場合に、ＶＡ２＞（Ｖ０−ＶＣ）／（１−Ｃｒ）の関係が成り立つように前記第２油戻し穴の高さ位置を設定したことにより、各室外機に対して冷凍機油が不均一に戻される場合は、各室外機でのアキュムレータに貯留される冷凍機油の量が可変し、アキュムレータに貯留される冷凍機油が第２油戻し穴を越えた室外機からは冷凍機油が多く排出されるため冷凍機油が減った室外機に対して冷凍機油を供給することができ、均油管を用いなくても各室外機の油量を一定量以上確保することができる。また、第２油戻し穴径の最大値をアキュムレータに付設する導出管内径と第１油戻し穴径の関係を用いて、冷媒かわき度が所定の値以下とならないように設定しているため、第２油戻し穴を越えてアキュムレータに液冷媒が戻った場合でも、圧縮機内の冷凍機油の粘度を確保可能な液量に調整されるため、圧縮機の信頼性を確保できる。更に、本室外機を単体で用いた場合や、複数台で用いた場合に各室外機に対して冷凍機油が均一に戻される場合は、アキュムレータ内に貯留される油と冷媒の混合流体の容積は、常に第２油戻し穴の位置よりも低いため、アキュムレータから圧縮機に流出する油循環量は、第１油戻し穴のみで決定されるため、圧縮機吸入側の冷媒ガス過熱度が抑制されるため、圧縮機吸入側の冷媒ガス密度の低下を抑制することができ、同一周波数で運転される圧縮機から流出する冷媒量を多くすることができるため、該空気調和装置の能力を向上することができる。また、この能力向上分を圧縮機周波数を抑制するように制御すれば、運転周波数を下げることができるため、圧縮機への電気入力量が低減でき、この電気入力の低減分だけ省エネルギー性が向上する。 Further, according to the present invention, the second oil return hole is formed in the middle of the outlet pipe in the container as the second oil flow rate adjusting mechanism in the accumulator of the air conditioner formed by connecting a plurality of outdoor units and indoor units. When the diameter of the second oil return hole is d2, the inner diameter of the outlet pipe is D, and the refrigerant solubility in the accumulator is Cr, d2 ≦ ((0.25 × (D) 0.9 ) 2 − (d1) 2 ) 0.5 The size of the second oil return hole diameter d2 is set so that (the oil flow rate flowing through the oil return circuit) <(the oil flow rate returning to the compressor through both the first oil return hole and the second oil return hole of the accumulator). , The internal volume of the accumulator from the height position of the second oil return hole to the bottom surface is VA2, the volume of oil enclosed in the air conditioner is V0, the volume of oil held in the compressor is VC, the refrigerant solubility in the accumulator When Cr is Cr, VA2> (V0-VC) / (1-C When the height position of the second oil return hole is set so that the relationship of r) is established, if the refrigeration oil is returned unevenly to each outdoor unit, it is stored in the accumulator in each outdoor unit. The amount of refrigerating machine oil that is variable and the refrigerating machine oil stored in the accumulator is discharged from the outdoor unit that has passed through the second oil return hole. The oil amount of each outdoor unit can be secured at a certain level or more without using an oil equalizing pipe. In addition, because the maximum value of the second oil return hole diameter is set so that the refrigerant degree does not become a predetermined value or less by using the relationship between the inner diameter of the outlet pipe attached to the accumulator and the first oil return hole diameter, Even when the liquid refrigerant returns to the accumulator beyond the second oil return hole, the liquid quantity is adjusted so that the viscosity of the refrigerating machine oil in the compressor can be secured, so that the reliability of the compressor can be secured. Furthermore, when the outdoor unit is used alone, or when the refrigeration oil is uniformly returned to each outdoor unit when multiple outdoor units are used, the volume of the mixed fluid of oil and refrigerant stored in the accumulator Is always lower than the position of the second oil return hole, and the amount of oil circulating from the accumulator to the compressor is determined only by the first oil return hole, so that the degree of refrigerant gas superheat on the compressor suction side is suppressed. Therefore, it is possible to suppress a decrease in refrigerant gas density on the compressor suction side, and to increase the amount of refrigerant flowing out from the compressor operated at the same frequency, thereby improving the performance of the air conditioner. can do. Also, if this capacity improvement is controlled so as to suppress the compressor frequency, the operating frequency can be lowered, so the amount of electrical input to the compressor can be reduced, and energy saving is improved by this reduction in electrical input. To do.
以下、本発明の一実施の形態を図１ないし図７を参照して説明する。 Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
図１は、本発明の実施例１における空気調和装置の冷媒回路図である。図１に示す空気調和装置は、少なくとも１台の室外機１と１台の室内機１０から構成されている。室外機１は、圧縮機２、油分離器３、逆止弁４、四方弁５、室外膨張弁６、室外熱交換器７、アキュムレータ８から構成され、図に示す如く順次配管接続されている。また、室外機１には、油分離器３の下部からアキュムレータ８の入口側に対してバイパス回路が形成され、該バイパス回路を流れる油量を調整するために油循環量調整装置９（例えば、キャピラリチューブ）が設けられている。さらに、圧縮機２下部の油貯留部には、圧縮機２内の油量が所定量以上となった場合に、圧縮機２の吐出側配管に油を排出するための排油管１５が設けられている。 FIG. 1 is a refrigerant circuit diagram of an air-conditioning apparatus according to Embodiment 1 of the present invention. The air conditioner shown in FIG. 1 includes at least one outdoor unit 1 and one indoor unit 10. The outdoor unit 1 includes a compressor 2, an oil separator 3, a check valve 4, a four-way valve 5, an outdoor expansion valve 6, an outdoor heat exchanger 7, and an accumulator 8, which are sequentially connected by piping as shown in the figure. . Further, in the outdoor unit 1, a bypass circuit is formed from the lower part of the oil separator 3 to the inlet side of the accumulator 8, and an oil circulation amount adjusting device 9 (for example, for adjusting the amount of oil flowing through the bypass circuit) Capillary tube) is provided. Further, the oil storage section below the compressor 2 is provided with an oil drain pipe 15 for discharging oil to the discharge side pipe of the compressor 2 when the amount of oil in the compressor 2 exceeds a predetermined amount. ing.
また、室内機１０は、室内熱交換器１１と室内膨張弁１２から構成され、前記室外機１と室内機１０は、ガス配管と液配管により配管接続されている。 The indoor unit 10 includes an indoor heat exchanger 11 and an indoor expansion valve 12. The outdoor unit 1 and the indoor unit 10 are connected by gas piping and liquid piping.
次に、本発明の空気調和装置に付設するアキュムレータ８の構造について説明する。 Next, the structure of the accumulator 8 attached to the air conditioner of the present invention will be described.
図２は、本発明の実施例１における空気調和装置に用いたアキュムレータ８の構造図である。冷媒及び油を貯留するための容器２０に対して、アキュムレータ８内に冷媒及び油を導入するための導入管２１と、アキュムレータ８から圧縮機２に冷媒及び油を排出するための導出管２２を設けた構造である。前記導出管２２には、該導出管２２の最下部に冷媒と油の混合液体を所定量だけ吸い込むための第１油戻し穴２３が、アキュムレータ８の容器２０の最下端部から所定の距離Ｈ１の位置に設けられ、前記導出管２２の上部には導出管２２内部と容器２０内の圧力差を解消するための均圧穴２４が設けられた構造となっている。 FIG. 2 is a structural diagram of the accumulator 8 used in the air conditioner according to the first embodiment of the present invention. An inlet pipe 21 for introducing refrigerant and oil into the accumulator 8 and a lead-out pipe 22 for discharging the refrigerant and oil from the accumulator 8 to the compressor 2 with respect to the container 20 for storing the refrigerant and oil. This is the structure provided. The outlet pipe 22 has a first oil return hole 23 for sucking a predetermined amount of the mixed liquid of refrigerant and oil into the lowermost portion of the outlet pipe 22 from the lowermost end portion of the container 20 of the accumulator 8 at a predetermined distance H1. The pressure equalizing hole 24 for eliminating the pressure difference between the inside of the outlet tube 22 and the inside of the container 20 is provided in the upper portion of the outlet tube 22.
次に、本発明の空気調和装置の冷媒及び冷凍機油の流れについて説明する。 Next, the flow of the refrigerant and the refrigerating machine oil of the air conditioner of the present invention will be described.
まず、冷房運転の場合は、室外機１の圧縮機２から吐出される高温、高圧の冷凍機油とガス冷媒は油分離器３に流入し、油分離器３で冷凍機油とガス冷媒に分離され、大部分の冷凍機油は油循環量調整装置９で流量が調整されアキュムレータ８に流入する。一方、油分離器３で分離しきれなかった冷凍機油とガス冷媒は、逆止弁４、四方弁５を通り室外熱交換器７に流入する。ここで、室外熱交換器７に流入する空気と熱交換して放熱し高圧の液冷媒となり、室外膨張弁６を通り室外機１を出て液接続配管を通り室内機１０に流入する。室内機１０に流入した液冷媒と冷凍機油は、室内膨張弁１２で減圧され低圧となり、室内熱交換器１１に流入し室内熱交換器１１に流入する空気と熱交換して吸熱しガス化して、室内機１０から流出してガス接続配管を通り室外機１に流入し、四方弁５を通りアキュムレータ８に流入し、アキュムレータ８で圧縮機２に流入する油循環量が調整されガス冷媒と一緒に圧縮機２に戻ることで冷凍サイクルが形成される。 First, in the case of cooling operation, high-temperature and high-pressure refrigeration oil and gas refrigerant discharged from the compressor 2 of the outdoor unit 1 flow into the oil separator 3 and are separated into refrigeration oil and gas refrigerant by the oil separator 3. Most of the refrigerating machine oil is adjusted in flow rate by the oil circulation amount adjusting device 9 and flows into the accumulator 8. On the other hand, the refrigerating machine oil and the gas refrigerant that could not be separated by the oil separator 3 flow into the outdoor heat exchanger 7 through the check valve 4 and the four-way valve 5. Here, heat is exchanged with the air flowing into the outdoor heat exchanger 7 to dissipate heat to become a high-pressure liquid refrigerant, passes through the outdoor expansion valve 6, exits the outdoor unit 1, and flows into the indoor unit 10 through the liquid connection pipe. The liquid refrigerant and the refrigeration oil that flowed into the indoor unit 10 are decompressed by the indoor expansion valve 12 to become low pressure, exchange heat with the air that flows into the indoor heat exchanger 11 and flows into the indoor heat exchanger 11, absorbs heat, and is gasified. , Flows out from the indoor unit 10, flows into the outdoor unit 1 through the gas connection pipe, flows into the accumulator 8 through the four-way valve 5, and the amount of oil circulation flowing into the compressor 2 is adjusted by the accumulator 8 together with the gas refrigerant. Returning to the compressor 2, a refrigeration cycle is formed.
次に、暖房運転の場合は、室外機１の圧縮機２から吐出される高温、高圧の冷凍機油とガス冷媒は油分離器３に流入し、油分離器３で冷凍機油とガス冷媒に分離され、大部分の冷凍機油は油循環量調整装置９で流量が調整されアキュムレータ８に流入する。一方、油分離器３で分離しきれなかった冷凍機油とガス冷媒は、逆止弁４、四方弁５を通り室外機１を出てガス接続配管を通り室内機１０に流入する。室内機１０に流入した冷凍機油とガス冷媒は、室内熱交換器１１に流入し、室内熱交換器１１に流入する空気と熱交換して放熱し液化して、室内膨張弁１２を通り室内機１０ａから流出して液接続配管を通り、室外機１に流入される。そして、室外機１に流入した冷凍機油と液冷媒は室外膨張弁６で減圧され低圧となり室外熱交換器７に流入し、室外熱交換器７に流入する空気と熱交換して吸熱しガス化して、四方弁５を通りアキュムレータ８に流入し、アキュムレータ８で圧縮機２に流入する油循環量が調整されガス冷媒と一緒に圧縮機２に戻ることで冷凍サイクルが形成される。 Next, in the case of heating operation, the high-temperature and high-pressure refrigeration oil and gas refrigerant discharged from the compressor 2 of the outdoor unit 1 flow into the oil separator 3 and are separated into refrigeration oil and gas refrigerant by the oil separator 3. The flow rate of most of the refrigeration oil is adjusted by the oil circulation amount adjusting device 9 and flows into the accumulator 8. On the other hand, the refrigerating machine oil and the gas refrigerant that could not be separated by the oil separator 3 pass through the check valve 4 and the four-way valve 5, exit the outdoor unit 1, and flow into the indoor unit 10 through the gas connection pipe. The refrigerating machine oil and the gas refrigerant that have flowed into the indoor unit 10 flow into the indoor heat exchanger 11, exchange heat with the air that flows into the indoor heat exchanger 11, dissipate and liquefy, and pass through the indoor expansion valve 12. The liquid flows out from 10a, passes through the liquid connection pipe, and flows into the outdoor unit 1. The refrigerating machine oil and the liquid refrigerant flowing into the outdoor unit 1 are decompressed by the outdoor expansion valve 6 and become low pressure, flow into the outdoor heat exchanger 7, exchange heat with the air flowing into the outdoor heat exchanger 7, and absorb heat to gasify. Then, the refrigerant flows into the accumulator 8 through the four-way valve 5, the amount of oil circulating into the compressor 2 is adjusted by the accumulator 8, and the refrigeration cycle is formed by returning to the compressor 2 together with the gas refrigerant.
次に、本実施例１の空気調和装置の全運転範囲内における油循環量特性について説明する。 Next, the oil circulation amount characteristic in the entire operation range of the air conditioner of the first embodiment will be described.
図３は、本発明の実施例１で用いられるアキュムレータと返油量調整装置の油循環量の関係を表した特性図である。本図の横軸は冷凍サイクルの吸入圧力Ｐｓを示し、縦軸は図２に示す構造のアキュムレータ８及び油循環量調整装置９を流れる油循環量Ｇｏを示す。 FIG. 3 is a characteristic diagram showing the relationship between the accumulator used in Example 1 of the present invention and the oil circulation amount of the oil return amount adjusting device. The horizontal axis of this figure represents the suction pressure Ps of the refrigeration cycle, and the vertical axis represents the oil circulation amount Go flowing through the accumulator 8 and the oil circulation amount adjusting device 9 having the structure shown in FIG.
本実施例１の空気調和装置の全運転範囲内における油循環量調整装置９を流れる油循環量は、実線矩形で囲まれた範囲内に調整され、図２に示す構造のアキュムレータ８から流出する油循環量は、一点鎖線で示される状態に調整される。 The oil circulation amount flowing through the oil circulation amount adjusting device 9 within the entire operation range of the air conditioner of Embodiment 1 is adjusted within the range surrounded by the solid line rectangle, and flows out from the accumulator 8 having the structure shown in FIG. The amount of oil circulation is adjusted to the state indicated by the alternate long and short dash line.
本実施例１の空気調和装置では、アキュムレータ８の油循環量は、常に油循環量調整装置９の油循環量よりも少ない状態に調整されるため、油分離器３に流入する油循環量よりも油分離器３から流出する油循環量の方が常に多くなるため、油分離器３内は常に空の状態となり、油循環量調整装置９は冷凍機油とガス冷媒の混合流体として流れることで、油分離器３の流入と流出の油循環量のバランスが保たれる。このため、空気調和装置に封入された冷凍機油の内、冷凍サイクル内を循環する冷凍機油以外の余剰冷凍機油は、全てアキュムレータ８に貯留されることになる。 In the air conditioner of the first embodiment, the oil circulation amount of the accumulator 8 is always adjusted to a state smaller than the oil circulation amount of the oil circulation amount adjustment device 9, so that the oil circulation amount flowing into the oil separator 3 Since the oil circulation amount flowing out from the oil separator 3 is always larger, the oil separator 3 is always empty, and the oil circulation amount adjusting device 9 flows as a mixed fluid of refrigerating machine oil and gas refrigerant. The balance between the oil circulation amount of the inflow and the outflow of the oil separator 3 is maintained. For this reason, of the refrigerating machine oil sealed in the air conditioner, all the surplus refrigerating machine oil other than the refrigerating machine oil circulating in the refrigerating cycle is stored in the accumulator 8.
上記のように設定されたアキュムレータ８及び油循環量調整装置９を用いた場合の冷凍サイクル中の油上がり率αｓは、油分離器３内には冷凍機油が溜まらない状態であるため、冷凍機油とガス冷媒を分離する空間を常に最大にすることができ、油分離器３の分離効率を最大に引き出すことが可能となり、冷凍サイクル中に流出する冷凍機油を最小に抑えることができる。 The oil rising rate αs during the refrigeration cycle when the accumulator 8 and the oil circulation amount adjusting device 9 set as described above are used is a state in which the refrigeration oil does not accumulate in the oil separator 3. The space for separating the gas refrigerant can be maximized at all times, the separation efficiency of the oil separator 3 can be maximized, and the refrigerating machine oil flowing out during the refrigeration cycle can be minimized.
本実施例１の冷凍サイクル中の油上がり率をαｓとした場合、以下に示す計算式により求めることができる。
αｓ＝（１−ηｏ）×（１−Ｘ１）×（１−Ｃｒ） …（数式１）
When the oil rising rate in the refrigeration cycle of Example 1 is αs, it can be obtained by the following calculation formula.
αs = (1-ηo) × (1-X1) × (1-Cr) (Formula 1)
ここで、ηｏは、油分離器３の分離効率、Ｘ１はアキュムレータ８の第１油戻し穴２３による冷媒かわき度、Ｃｒはアキュムレータ８内の冷媒と油の溶解比率である冷媒溶解度を表している。前述したように、本実施例１では、余剰冷凍機油を常にアキュムレータ８内に貯留しているため、油分離器３の分離効率を最大（例えば、０.９８）にすることができるため、冷凍サイクル中の油上がり率αｓも小さくすることができる。しかし、アキュムレータ８の第１油戻し穴２３による冷媒かわき度が大きい場合は、油分離器３の分離効率が高い場合でも、冷凍サイクル中の油上がり率は大きくなってしまう。 Here, ηo represents the separation efficiency of the oil separator 3, X 1 represents the degree of refrigerant clearance by the first oil return hole 23 of the accumulator 8, and Cr represents the refrigerant solubility, which is the dissolution ratio of refrigerant to oil in the accumulator 8. . As described above, in the first embodiment, surplus refrigeration oil is always stored in the accumulator 8, so that the separation efficiency of the oil separator 3 can be maximized (for example, 0.98). The oil rising rate αs during the cycle can also be reduced. However, when the degree of refrigerant pumping by the first oil return hole 23 of the accumulator 8 is large, even if the separation efficiency of the oil separator 3 is high, the oil rising rate in the refrigeration cycle becomes large.
そこで、本発明の実施例１では、第１油戻し穴２３による冷媒かわき度をある範囲に規定することで、冷凍サイクル中の油上がり率を小さく抑えて、空気調和装置の性能を向上するようにした。空気調和装置の性能を向上するためには、接続配管や熱交換器等での圧力損失を低減し、且つ熱交換器の配管内の油膜が形成されにくくして熱交換効率を高くする必要があり、そのためには冷凍サイクル中の油上がり率を０.１wt％以下にする必要がある。本実施例では油上がり率を０.１wt％以下とするために冷媒かわき度がある範囲内となるようにするものであり、このための第１油戻し穴２３と導出管２２との関係を特定するものである。なお、空気調和装置の通常運転範囲からアキュムレータの冷媒溶解度Ｃｒを０.３とすると（数式１）から油上がり率を０.１wt％以下するための第１油戻し穴２３による冷媒かわき度は０.９３以上とする必要がある。 Therefore, in the first embodiment of the present invention, the degree of refrigerant pumping by the first oil return hole 23 is regulated within a certain range, so that the oil rising rate in the refrigeration cycle is suppressed to be small and the performance of the air conditioner is improved. I made it. In order to improve the performance of the air conditioner, it is necessary to reduce the pressure loss in the connection pipes and heat exchangers, and to increase the heat exchange efficiency by making it difficult to form an oil film in the pipes of the heat exchangers. For this purpose, the oil rising rate in the refrigeration cycle needs to be 0.1 wt% or less. In this embodiment, in order to set the oil rising rate to 0.1 wt% or less, the degree of refrigerant is within a certain range, and the relationship between the first oil return hole 23 and the outlet pipe 22 for this purpose is as follows. It is something to identify. Note that if the refrigerant solubility Cr of the accumulator is 0.3 from the normal operating range of the air conditioner, the refrigerant pumping degree by the first oil return hole 23 for reducing the oil rising rate to 0.1 wt% or less from (Equation 1) is 0. It should be .93 or higher.
なお、アキュムレータ８の第１油戻し穴２３による冷媒かわき度は、導出管２２の入口から第１油戻し穴２３までを流れるガス冷媒の抵抗と、第１油戻し穴２３から流入する冷凍機油と冷媒が混合した液体の抵抗のバランスにより決定される。そこで、発明者等は、第１油戻し穴２３の穴径をｄ１、導出管２２の内径をＤ、Ａを比例定数として以下に示す数式１を考え、このＡがどの範囲内にあれば冷媒かわき度が０.９３〜０.９７の範囲内になるか実験により求めた。なお、この場合の冷媒かわき度は、定格運転を行ったときのものである。
ｄ１＝Ａ×（Ｄ）0.9 …（数式２）
Note that the degree of refrigerant pumping by the first oil return hole 23 of the accumulator 8 is the resistance of the gas refrigerant flowing from the inlet of the outlet pipe 22 to the first oil return hole 23, and the refrigerating machine oil flowing from the first oil return hole 23. It is determined by the balance of the resistance of the liquid mixed with the refrigerant. Accordingly, the inventors consider the following Equation 1 where the hole diameter of the first oil return hole 23 is d1, the inner diameter of the outlet pipe 22 is D, and A is a proportionality constant. It was experimentally determined whether the degree of clearance was in the range of 0.93 to 0.97. In this case, the degree of refrigerant pumping is that when rated operation is performed.
d1 = A × (D) 0.9 (Expression 2)
空気調和装置の信頼性を確保するためアキュムレータ８から圧縮機２に油を供給する第１油戻し穴２３の詰まり防止から、第１油戻し穴２３の穴径ｄ１は少なくとも１.０mm以上を確保する必要がある。ここで一般的に空気調和装置に用いられているアキュムレータ８の導出管２２の内径寸法としてφ１３.８８mm〜φ２３mmを考えると、第１油戻し穴２３の穴径ｄ１は１mm以上、かつ、導出管２２の内径をＤはφ１３.８８mm以上を満たすためのＡの範囲は０.１＜Ａとなる。本発明者等の実験によれば、Ａを０.１よりわずかに大きな範囲とすると、冷媒かわき度は約０.９７となることが確認された。 To prevent the clogging of the first oil return hole 23 that supplies oil from the accumulator 8 to the compressor 2 in order to ensure the reliability of the air conditioner, the hole diameter d1 of the first oil return hole 23 should be at least 1.0 mm or more. There is a need to. Here, considering φ13.88 mm to φ23 mm as the inner diameter of the outlet pipe 22 of the accumulator 8 generally used in an air conditioner, the hole diameter d1 of the first oil return hole 23 is 1 mm or more, and the outlet pipe The range of A for satisfying the inner diameter of 22 and D being φ13.88 mm or more is 0.1 <A. According to the experiments by the present inventors, it has been confirmed that when A is set in a range slightly larger than 0.1, the refrigerant clearance is about 0.97.
一方で上記した通り、冷媒かわき度は０.９３以上とする必要があり、この場合のＡの範囲は、発明者等の実験により、Ａを０.１６より小さい範囲とすることで冷媒かわき度が０.９３以上となることが分かった。以上に説明したように、（数式２）に示すＡの値を０.１＜Ａ＜０.１６とすることで冷媒かわき度を０.９３〜０.９７とすることができる。したがって、このＡの範囲となるようにアキュムレータ８の導出管２２及び第１油戻し穴径２３を決定することで、冷凍サイクル中の油上がり率を０.１wt％以下にすることができ、空気調和装置の性能を向上することができる。 On the other hand, as described above, it is necessary that the refrigerant draft is 0.93 or more. In this case, the range of A is determined by an experiment by the inventors and the like by setting A to a range smaller than 0.16. Was found to be 0.93 or more. As described above, by setting the value of A shown in (Equation 2) to 0.1 <A <0.16, the refrigerant writing degree can be set to 0.93 to 0.97. Therefore, by determining the outlet pipe 22 and the first oil return hole diameter 23 of the accumulator 8 so as to be in the range of A, the oil rising rate in the refrigeration cycle can be reduced to 0.1 wt% or less. The performance of the harmony device can be improved.
図４は、本発明の実施例２における空気調和装置の冷媒回路図である。本実施例２の空気調和装置は、２つの室外機１ａ、１ｂと２つの室内機１０ａ、１０ｂから構成されている。室外機１ａは、圧縮機２ａ、油分離器３ａ、逆止弁４ａ、四方弁５ａ、室外膨張弁６ａ、室外熱交換器７ａ、アキュムレータ８ａから構成され図の如く順次配管接続され、室外機１ｂも室外機１ａと同様に圧縮機２ｂ、油分離器３ｂ、逆止弁４ｂ、四方弁５ｂ、室外膨張弁６ｂ、室外熱交換器７ｂ、アキュムレータ８ｂから構成され図の如く順次配管接続されている。また、室内機１０ａは、室内熱交換器１１ａと室内膨張弁１２ａから構成され、室内機１０ｂも室内機１０ａと同様に室内熱交換器１１ｂと室内膨張弁１２ｂから構成されている。そして、前記室外機１ａ、室外機１ｂと室内機１０ａ、室内機１０ｂは、ガス側分配器１３と液側分配器１４を介して並列に配管接続されている。 FIG. 4 is a refrigerant circuit diagram of the air-conditioning apparatus according to Embodiment 2 of the present invention. The air conditioner according to the second embodiment includes two outdoor units 1a and 1b and two indoor units 10a and 10b. The outdoor unit 1a is composed of a compressor 2a, an oil separator 3a, a check valve 4a, a four-way valve 5a, an outdoor expansion valve 6a, an outdoor heat exchanger 7a, and an accumulator 8a. Similarly to the outdoor unit 1a, the compressor 2b, the oil separator 3b, the check valve 4b, the four-way valve 5b, the outdoor expansion valve 6b, the outdoor heat exchanger 7b, and the accumulator 8b are connected in series as shown in the figure. . Moreover, the indoor unit 10a is comprised from the indoor heat exchanger 11a and the indoor expansion valve 12a, and the indoor unit 10b is comprised from the indoor heat exchanger 11b and the indoor expansion valve 12b similarly to the indoor unit 10a. The outdoor unit 1a, the outdoor unit 1b, the indoor unit 10a, and the indoor unit 10b are connected to each other in parallel via a gas side distributor 13 and a liquid side distributor 14.
また、室外機１ａ、１ｂには、油分離器３ａ、３ｂの下部からアキュムレータ８ａ、８ｂの入口側に対してバイパス回路が形成され、該バイパス回路の油循環量を調整する油循環量調整装置９ａ、９ｂ（例えば、キャピラリチューブ）が設けられている。また、圧縮機２ａ、２ｂ下部の油貯留部には、圧縮機２ａ、２ｂ内の油量が所定量以上となった場合に、圧縮機２ａ、２ｂの吐出側配管に油を排出するための排油管１５ａ、１５ｂが設けられている。 Further, in the outdoor units 1a and 1b, a bypass circuit is formed from the lower part of the oil separators 3a and 3b to the inlet side of the accumulators 8a and 8b, and an oil circulation amount adjusting device for adjusting the oil circulation amount of the bypass circuit 9a and 9b (for example, capillary tubes) are provided. In addition, an oil storage section below the compressors 2a and 2b is used to discharge oil to the discharge side piping of the compressors 2a and 2b when the amount of oil in the compressors 2a and 2b exceeds a predetermined amount. Oil drain pipes 15a and 15b are provided.
また、図５は、本実施例２の空気調和装置の室外機１ａ、１ｂに用いたアキュムレータ８ａ、８ｂの断面を示した構造図である。ここで、図２と同符号のものは同一のものを示す。本実施例２のアキュムレータ８ａ、８ｂは、実施例１で用いたアキュムレータ８に対して、第１油戻し穴２３の高さＨ１より高く、均圧穴２４の高さより低い高さＨ２の位置の導出管２２に第２油戻し穴２５を設けた構成となっている。 FIG. 5 is a structural diagram showing a cross section of accumulators 8a and 8b used in the outdoor units 1a and 1b of the air-conditioning apparatus of the second embodiment. Here, the same reference numerals as those in FIG. 2 denote the same elements. The accumulators 8a and 8b of the second embodiment derive the position of the height H2 that is higher than the height H1 of the first oil return hole 23 and lower than the height of the pressure equalizing hole 24 with respect to the accumulator 8 used in the first embodiment. The second oil return hole 25 is provided in the pipe 22.
本実施例の空気調和装置は、この室外機１ａ、１ｂと２台を接続するため、一方の室外機への冷凍機油の分配比が少なくなると冷凍機油の保有量が減少し、冷凍機油不足を起こす可能性がある。そこで本実施例では実施例１に比べてアキュムレータ８ａ、８ｂからの油を多く戻すことが望ましい。これにより油分配の多い室外機は、後で説明する図７のＡ点以上の油封入量となるため、室外機から流出する油上がり率は、他方の室外機と比較して多くなるため、分配比の少ない室外機側にも十分な冷凍機油を供給することが可能となり、分配比の少ない室外機側のアキュムレータ内の液面低下が止まり、各室外機の油量を一定量以上確保することができる。 Since the air conditioner of this embodiment connects the two outdoor units 1a and 1b, when the distribution ratio of the refrigerating machine oil to one outdoor unit decreases, the amount of refrigerating machine oil decreases, and the refrigerating machine oil shortage occurs. There is a possibility of waking up. Therefore, in this embodiment, it is desirable to return more oil from the accumulators 8a and 8b than in the first embodiment. As a result, the outdoor unit with a lot of oil distribution has an oil filling amount equal to or higher than point A in FIG. 7 to be described later, so the oil rising rate flowing out of the outdoor unit is larger than that of the other outdoor unit, Sufficient refrigeration oil can be supplied to the outdoor unit with a small distribution ratio, the liquid level in the accumulator on the outdoor unit with a low distribution ratio stops, and the amount of oil in each outdoor unit is secured above a certain level. be able to.
ここで、前記第２油戻し穴２５の径をｄ２とした場合、上記の理由からｄ２の径を大きくして多くの冷凍機油を第２油戻し穴２５から戻すことが望ましい。しかしながら、あまりにもｄ２の径を大きくすると、冷凍機油とともに冷媒が圧縮機に戻るため、冷凍機油の粘度低下を招く虞があるため、これを防止する必要がある。そこで、本実施例においては、この粘度低下の限界値として、アキュムレータから戻る冷媒の冷媒かわき度を０.８４以上とする。この冷媒かわき度を０.８４以上とするときの数式２のＡを本発明者等が実験により求めたところ、Ａを０.２５以下とすることが必要であることが分かった。すると導出管２２の内径をＤ、第１油戻し穴２３の径をｄ１とした場合、以下に示す式により第２油戻し穴２５の最大値が決定される。
ｄ２≦（（０.２５×（Ｄ）0.9）2−（ｄ１）2）0.5 …（数式３）
Here, when the diameter of the second oil return hole 25 is d2, it is desirable to increase the diameter of d2 and return a lot of refrigerating machine oil from the second oil return hole 25 for the above reason. However, if the diameter of d2 is too large, the refrigerant returns to the compressor together with the refrigerating machine oil, which may cause a decrease in the viscosity of the refrigerating machine oil. Therefore, in the present embodiment, as the limit value of the viscosity decrease, the refrigerant degree of the refrigerant returning from the accumulator is set to 0.84 or more. As a result of experiments conducted by the present inventors to obtain A in Formula 2 when the refrigerant degree is 0.84 or more, it has been found that A needs to be 0.25 or less. Then, when the inner diameter of the outlet pipe 22 is D and the diameter of the first oil return hole 23 is d1, the maximum value of the second oil return hole 25 is determined by the following equation.
d2 ≦ ((0.25 × (D) 0.9 ) 2 − (d1) 2 ) 0.5 (Expression 3)
また、（返油量調整装置を流れる油循環量）＜（アキュムレータの第１油戻し穴と第２油戻し穴の両方で圧縮機に戻る油循環量）となるように第２油戻し穴２５の穴径ｄ２が設定される。また、第２油戻し穴２５の高さ位置Ｈ２から底面までのアキュムレータ８ａ、８ｂの内容積をＶＡ２、該空気調和装置に封入する油体積量をＶ０、圧縮機２ａ、２ｂに保有される油体積量をＶＣ、アキュムレータ８ａ、８ｂ内の冷媒溶解度をＣｒとした場合、以下に示す式が成り立つように第２油戻し穴２５の高さ位置Ｈ２が設定される。
ＶＡ２＞（Ｖ０−ＶＣ）／（１−Ｃｒ） …（数式４）
Further, the second oil return hole 25 so that (the amount of oil circulation flowing through the oil return amount adjusting device) <(the amount of oil circulation returning to the compressor through both the first oil return hole and the second oil return hole of the accumulator). The hole diameter d2 is set. Further, the internal volume of the accumulators 8a and 8b from the height position H2 to the bottom surface of the second oil return hole 25 is VA2, the volume of oil sealed in the air conditioner is V0, and the oil held in the compressors 2a and 2b. When the volume is VC and the refrigerant solubility in the accumulators 8a and 8b is Cr, the height position H2 of the second oil return hole 25 is set so that the following formula is established.
VA2> (V0-VC) / (1-Cr) (Formula 4)
次に、本実施例２の空気調和装置の全運転範囲内における油循環量特性について説明する。 Next, the oil circulation amount characteristic in the entire operation range of the air conditioner of the second embodiment will be described.
図６は、本発明の実施例２で用いられるアキュムレータ８ａ、８ｂと油循環量調整装置９ａ、９ｂの油循環量の関係を表した特性図である。本図の横軸は冷凍サイクルの吸入圧力Ｐｓを示し、縦軸は図２に示す構造のアキュムレータ８ａ、８ｂ及び油循環量調整装置９ａ、９ｂを流れる油循環量Ｇｏを示す。 FIG. 6 is a characteristic diagram showing the relationship between the oil circulation amounts of the accumulators 8a and 8b and the oil circulation amount adjusting devices 9a and 9b used in the second embodiment of the present invention. The horizontal axis of this figure indicates the suction pressure Ps of the refrigeration cycle, and the vertical axis indicates the oil circulation amount Go flowing through the accumulators 8a and 8b and the oil circulation amount adjusting devices 9a and 9b having the structure shown in FIG.
本実施例２の空気調和装置の全運転範囲内における油循環量調整装置９ａ、９ｂを流れる油循環量は、実線矩形で囲まれた範囲内に調整され、図５に示す構造のアキュムレータ８ａ、８ｂの第２油戻し穴２５の位置Ｈ２よりも少ない液量の場合、すなわち第１油戻し穴２３のみで流出する油循環量は、油循環量調整装置９ａ、９ｂを流れる油循環量よりも少ない一点鎖線で示される状態に調整される。また、第２油戻し穴２５位置Ｈ２よりも多い液量の場合、すなわち第１油戻し穴２３と第２油戻し穴２５の両方で流出する油循環量は、油循環量調整装置９ａ、９ｂを流れる油循環量よりも多い破線の状態に調整される。 The oil circulation amount flowing through the oil circulation amount adjusting devices 9a and 9b within the entire operation range of the air conditioner of the second embodiment is adjusted within the range surrounded by the solid line rectangle, and the accumulator 8a having the structure shown in FIG. In the case where the amount of liquid is smaller than the position H2 of the second oil return hole 25 of 8b, that is, the oil circulation amount flowing out only by the first oil return hole 23 is larger than the oil circulation amount flowing through the oil circulation amount adjusting devices 9a and 9b. It is adjusted to the state shown by a few alternate long and short dash lines. Further, when the amount of liquid is larger than the position H2 of the second oil return hole 25, that is, the amount of oil circulation flowing out from both the first oil return hole 23 and the second oil return hole 25 is the oil circulation amount adjusting device 9a, 9b. It is adjusted to the state of a broken line that is larger than the amount of circulating oil.
次に、本実施例２の空気調和装置の冷凍サイクル中の油上がり率αｓについて説明する。 Next, the oil rising rate αs during the refrigeration cycle of the air conditioner of Embodiment 2 will be described.
図７は、本実施例２の空気調和装置において、冷凍サイクルシステム内に封入される油封入量Ｗｏとサイクル内油上がり率αｓの関係を表した特性図である。本図に示すＡ点は、アキュムレータ８ａ、８ｂ内に貯留される冷凍機油と冷媒の混合液体が、第２油戻し穴２５の位置Ｈ２の状態を表している。 FIG. 7 is a characteristic diagram showing the relationship between the oil filling amount Wo enclosed in the refrigeration cycle system and the oil rise rate αs in the cycle in the air conditioner of the second embodiment. Point A shown in the drawing represents the state of the position H2 of the second oil return hole 25 where the mixed liquid of the refrigerating machine oil and the refrigerant stored in the accumulators 8a and 8b.
すなわち、アキュムレータ８ａ、８ｂ内に貯留される液量が、第２油戻し穴２５の位置Ｈ２よりも少なくなるようなシステム内の油封入量Ｗ１の場合、アキュムレータ８ａ、８ｂと油循環量調整装置９ａ、９ｂの油循環量の関係が図６に示す一点鎖線の状態となるため、常に油分離器３ａ、３ｂ内には冷凍機油が溜まらない状態となり、冷凍機油とガス冷媒を分離する空間を常に最大にすることができ、油分離器３ａ、３ｂの分離効率を最大に引き出すことが可能となり、冷凍サイクル中に流出する冷凍機油を最小に抑えることができる。また、本図に示すＡ点を越えるようなシステム内の油封入量Ｗ２の場合は、アキュムレータ８ａ、８ｂと油循環量調整装置９ａ、９ｂの油循環量の関係が図６に示す破線の状態となるため、返油量調整装置の油循環量よりも常にアキュムレータから流出する油循環量が多くなるため、アキュムレータ内に貯留されている冷凍機油が油分離器内に移動し、冷凍機油とガス冷媒を分離する空間が減少するため、油分離器３ａ、３ｂの分離効率が低下するため冷凍サイクル内の油上がり率αｓも急激に多くなる特性となる。 That is, when the amount of liquid stored in the accumulators 8a and 8b is the oil filling amount W1 in the system such that the amount of liquid stored in the accumulators 8a and 8b is smaller than the position H2 of the second oil return hole 25, the accumulators 8a and 8b and the oil circulation amount adjusting device Since the relationship between the oil circulation amounts of 9a and 9b is in the state of the alternate long and short dash line shown in FIG. It can always be maximized, the separation efficiency of the oil separators 3a, 3b can be maximized, and the refrigerating machine oil flowing out during the refrigeration cycle can be minimized. Further, in the case of the oil filling amount W2 in the system exceeding the point A shown in this figure, the relationship between the oil circulation amounts of the accumulators 8a and 8b and the oil circulation amount adjusting devices 9a and 9b is the state of the broken line shown in FIG. Therefore, the amount of oil circulation that always flows out of the accumulator is larger than the amount of oil circulation of the oil return amount adjustment device, so that the refrigerating machine oil stored in the accumulator moves into the oil separator, and the refrigerating machine oil and gas Since the space for separating the refrigerant is reduced, the separation efficiency of the oil separators 3a and 3b is lowered, so that the oil rising rate αs in the refrigeration cycle also increases rapidly.
すなわち、各室外機への油分配が均一な場合は、それぞれの室外機の油封入量は、Ａ点以下に調整されるため、各々の室外機から流出する油上がり率は、非常に小さな値となるため、冷凍サイクルの性能を向上することができる。また、各室外機への油分配が不均一な場合は、油分配の少ない室外機は、Ａ点以下の油封入量となるため室外機から流出する油上がり率は非常に小さな値となるが、（室外機からの油流出量）＞（室内から戻される油流入量）となるため、この室外機の冷凍機油の保有量が減少し、冷凍機油不足を起こす可能性がある。但し、油分配の多い室外機は、Ａ点以上の油封入量となるため、室外機から流出する油上がり率は、他方の室外機と比較して多くなるため、分配比の少ない室外機側にも十分な冷凍機油を供給することが可能となり、分配比の少ない室外機側のアキュムレータ内の液面低下が止まり、各室外機の油量を一定量以上確保することができる。すなわち、複数台の室外機を接続した場合において、油上がり率を最小減に抑えつつ、均油管無しで油分配を可能にすることができる。 That is, when the oil distribution to each outdoor unit is uniform, the oil filling amount of each outdoor unit is adjusted to the point A or less, so the oil rising rate flowing out from each outdoor unit is a very small value. Therefore, the performance of the refrigeration cycle can be improved. In addition, when the oil distribution to each outdoor unit is uneven, the outdoor unit with a small oil distribution has an oil filling amount of point A or less, so the rate of oil rising from the outdoor unit is very small. Since (Oil outflow from outdoor unit)> (Oil inflow returned from indoor), the amount of refrigerating machine oil held by this outdoor unit decreases, which may cause shortage of refrigerating machine oil. However, since the outdoor unit with a lot of oil distribution has an oil filling amount of point A or higher, the oil rising rate flowing out from the outdoor unit is larger than that of the other outdoor unit, so the outdoor unit side with a small distribution ratio In addition, sufficient refrigeration oil can be supplied, the liquid level in the accumulator on the outdoor unit side with a small distribution ratio can be stopped, and the oil amount of each outdoor unit can be secured at a certain level or more. That is, when a plurality of outdoor units are connected, it is possible to distribute oil without an oil equalizing pipe while suppressing the oil rising rate to a minimum.
ここで、実施例１ないし実施例２において、２台の室外機を並列に接続した内容について説明したが、３台ないし４台の室外機を並列に接続した場合も同様の効果があり、本発明の域を脱するものではない。 Here, in Embodiments 1 and 2, the content of connecting two outdoor units in parallel has been described. However, the same effect can be obtained when three or four outdoor units are connected in parallel. It does not depart from the scope of the invention.
１、１ａ、１ｂ 室外機
２、２ａ、２ｂ 圧縮機
３、３ａ、３ｂ 油分離器
６、６ａ、６ｂ 室外膨張弁
７、７ａ、７ｂ 室外熱交換器
８、８ａ、８ｂ アキュムレータ
９、９ａ、９ｂ 油循環量調整装置
１０、１０ａ、１０ｂ 室内機
１１、１１ａ、１１ｂ 室内熱交換器
１２、１２ａ、１２ｂ 室内膨張弁
１３ ガス側分配器
１４ 液側分配器
１５、１５ａ、１５ｂ 排油管
２０ 容器
２１ 導入管
２２ 導出管
２３ 第１油戻し穴
２４ 均圧穴
２５ 第２油戻し穴
1, 1a, 1b Outdoor unit 2, 2a, 2b Compressor 3, 3a, 3b Oil separator 6, 6a, 6b Outdoor expansion valve 7, 7a, 7b Outdoor heat exchanger 8, 8a, 8b Accumulator 9, 9a, 9b Oil circulation amount adjusting device 10, 10a, 10b Indoor unit 11, 11a, 11b Indoor heat exchanger 12, 12a, 12b Indoor expansion valve 13 Gas side distributor 14 Liquid side distributor 15, 15a, 15b Drain oil pipe 20 Container 21 Introduction Pipe 22 Lead pipe 23 First oil return hole 24 Pressure equalization hole 25 Second oil return hole
Claims (3)
室内熱交換器と減圧装置と、を有した室内機と、を接続して成る空気調和装置において、
前記アキュムレータは、油流量調整機構として容器内の導出管の下部に第１油戻し穴が形成されるとともに、前記第１油戻し穴によるかわき度をＸ１、該第１油戻し穴の径をｄ１、前記導出管の内径をＤ、前記圧縮機の最大油上がり率をα、前記アキュムレータ内の冷媒溶解度をＣｒとした場合、ｄ１＝Ａ×（Ｄ）0.9、且つ０.１＜Ａ＜０.１６で、且つα＜（１−Ｘ１）×（１−Ｃｒ）となるように前記導出管の内径Ｄ、前記第１油戻し穴の径ｄ１が設定され、
（前記油循環量調装置を流れる油流量）≧（アキュムレータの第１油戻し穴で圧縮機に戻る油流量）となるように前記油循環量調装置の内径及び長さを設定し、余剰油がアキュムレータ内に貯留されるようにしたことを特徴とする空気調和装置。 A compressor, an oil separator, an outdoor heat exchanger, a pressure reducing device, an accumulator, and an oil circulation amount adjusting device that is installed in a refrigerant pipe from the oil separator to the accumulator and through which refrigeration oil flows. Outdoor unit,
In an air conditioner formed by connecting an indoor unit having an indoor heat exchanger and a pressure reducing device,
In the accumulator, a first oil return hole is formed in the lower part of the outlet pipe in the container as an oil flow rate adjusting mechanism, the degree of clearance by the first oil return hole is X1, and the diameter of the first oil return hole is d1. When the inner diameter of the outlet pipe is D, the maximum oil rising rate of the compressor is α, and the refrigerant solubility in the accumulator is Cr, d1 = A × (D) 0.9 and 0.1 <A <0.00. 16 and the inner diameter D of the outlet pipe and the diameter d1 of the first oil return hole are set so that α <(1-X1) × (1-Cr).
The inner diameter and length of the oil circulation amount adjusting device are set so that (the oil flow amount flowing through the oil circulation amount adjusting device) ≧ (the oil flow rate returning to the compressor through the first oil return hole of the accumulator), and surplus oil Is stored in an accumulator.
前記第１油戻し穴で流出される冷媒かわき度が０．９３〜０．９７に設定されることを特徴とする空気調和装置。The air conditioner is characterized in that the degree of the refrigerant flowing out of the first oil return hole is set to 0.93 to 0.97.
室内熱交換器と減圧装置と、を有した複数台の室内機と、を接続して成る空気調和装置において、
前記アキュムレータは、第１の油流量調整機構として容器内の導出管の下部に第１油戻し穴が形成されるとともに、第２の油流量調整機構として前記導出管の中部に第２油戻し穴が形成され、
前記第１油戻し穴の径をｄ１、前記第２油戻し穴の径をｄ２、前記導出管の内径をＤ、とした場合に、
ｄ２≦（（０.２５×（Ｄ）0.9）2−（ｄ１）2）0.5、且つ（前記油循環量調整装置を流れる油循環量）＜（前記第１油戻し穴及び前記第２油戻し穴の両方から前記圧縮機に戻る油循環量）となるように設定され、且つ、
前記第２油戻し穴の高さ位置から底面までのアキュムレータ内容積をＶＡ２、該空気調和装置に封入する油体積量をＶ０、前記圧縮機に保有される油体積量をＶＣ、前記アキュムレータ内の冷媒溶解度をＣｒとした場合に、ＶＡ２＞（Ｖ０−ＶＣ）／（１−Ｃｒ）となるように前記第２油戻し穴の高さ位置が設定されたことを特徴とする空気調和装置。 A compressor, an oil separator, an outdoor heat exchanger, a pressure reducing device, an accumulator, and an oil circulation amount adjusting device that is installed in a refrigerant pipe from the oil separator to the accumulator and through which refrigeration oil flows. Multiple outdoor units,
In an air conditioner formed by connecting a plurality of indoor units having an indoor heat exchanger and a pressure reducing device,
The accumulator has a first oil return hole formed in the lower part of the outlet pipe in the container as a first oil flow rate adjusting mechanism, and a second oil return hole in the middle part of the outlet pipe as a second oil flow rate adjusting mechanism. Formed,
When the diameter of the first oil return hole is d1, the diameter of the second oil return hole is d2, and the inner diameter of the outlet pipe is D,
d2 ≦ ((0.25 × (D) 0.9 ) 2 − (d1) 2 ) 0.5 and (the amount of oil circulating through the oil circulation amount adjusting device) <(the first oil return hole and the second oil return) Oil circulation amount returning to the compressor from both of the holes), and
The internal volume of the accumulator from the height position of the second oil return hole to the bottom surface is VA2, the volume of oil enclosed in the air conditioner is V0, the volume of oil held in the compressor is VC, and the volume in the accumulator is An air conditioner in which the height position of the second oil return hole is set so that VA2> (V0-VC) / (1-Cr) when the refrigerant solubility is Cr.
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