JP2006125738A

JP2006125738A - Refrigeration unit

Info

Publication number: JP2006125738A
Application number: JP2004315080A
Authority: JP
Inventors: Hiroaki Tanaka; 宏明田中
Original assignee: Sanyo Electric Co Ltd
Current assignee: Sanyo Electric Co Ltd
Priority date: 2004-10-29
Filing date: 2004-10-29
Publication date: 2006-05-18
Anticipated expiration: 2024-10-29
Also published as: JP4601392B2

Abstract

PROBLEM TO BE SOLVED: To increase COP and to effectively cool a compressor while simplifying piping in a refrigeration unit of a constitution comprising a compressor, a heat source-side heat exchanger, a pressure reducer and a use-side heat exchanger, having a supercooling circuit between the pressure reducer and the use-side heat exchanger, and cooling the compressor by returning a liquid refrigerant to a suction pipe of the compressor when a discharge temperature of the compressor rises. SOLUTION: In an outdoor unit 2A of an air conditioner 1, an auxiliary cooling circuit 28 is mounted in a state of being communicated with a pipe 33 connecting between an expansion valve 26 and a liquid pipe 8, an outer pipe of the auxiliary cooling circuit 28 is connected to communicated with a branch pipe 34 and a refrigerant pipe 35, and an electrically-driven expansion valve 29 is mounted on the auxiliary cooling circuit 28. A valve opening of the electrically-driven expansion valve 29 is controlled by an outdoor controller 100. COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、過冷却熱交換器を備えた冷凍装置に関する。 The present invention relates to a refrigeration apparatus including a supercooling heat exchanger.

一般に、圧縮機、熱源側熱交換器、減圧装置及び利用側熱交換器を備えた冷凍装置が知られている。この種のものでは、冷凍装置のＣＯＰ（成績係数）を増大させるため、減圧装置と利用側熱交換器との間に、過冷却回路（例えば、熱交換器）を備えたものが提案されている（例えば、特許文献１参照）。また、この種のものでは、冷媒回路中の液管と、圧縮機の吸込管とをリキッド管で接続し、圧縮機の吐出温度が設定値を超えて大きく上昇した場合、圧縮機のモータ巻線を保護するため、リキッド管を通じて冷媒回路中の液冷媒を圧縮機の吸込管に戻して当該圧縮機を冷却するものが提案されている。
特許第２６６４４２１号公報 In general, a refrigeration apparatus including a compressor, a heat source side heat exchanger, a decompression device, and a use side heat exchanger is known. In this kind of thing, in order to increase COP (coefficient of performance) of a refrigerating machine, what provided the subcooling circuit (for example, heat exchanger) between a pressure reduction device and a use side heat exchanger is proposed. (For example, refer to Patent Document 1). Also, in this type, when the liquid pipe in the refrigerant circuit and the suction pipe of the compressor are connected by a liquid pipe and the discharge temperature of the compressor rises greatly exceeding the set value, the motor winding of the compressor In order to protect the wire, it has been proposed that the liquid refrigerant in the refrigerant circuit is returned to the suction pipe of the compressor through the liquid pipe to cool the compressor.
Japanese Patent No. 2664421

しかしながら、従来の構成では、ＣＯＰ（成績係数）の増大、並びに圧縮機の効果的な冷却を実現するため、上記冷媒回路中に、過冷却回路、並びにリキッド管等を設けなければならず、余分な配管、弁類が必要になり、それに伴い制御が煩雑化すると共に、製造コストが増大する等の問題があった。 However, in the conventional configuration, in order to realize an increase in COP (coefficient of performance) and effective cooling of the compressor, a supercooling circuit, a liquid pipe, and the like must be provided in the refrigerant circuit. Piping and valves are required, which causes problems such as complicated control and increased manufacturing costs.

そこで、本発明の目的は、上述した従来の技術が有する課題を解消し、配管類の簡素化を図った上で、ＣＯＰ（成績係数）の増大、並びに圧縮機の効果的な冷却を実現することができる冷凍装置を提供することにある。 Accordingly, an object of the present invention is to solve the problems of the conventional techniques described above, simplify piping, and increase COP (coefficient of performance) and effectively cool the compressor. An object of the present invention is to provide a refrigeration apparatus that can be used.

上記課題を解決するため、本発明は、圧縮機、熱源側熱交換器、減圧装置及び利用側熱交換器を備えた冷凍装置において、前記減圧装置と前記利用側熱交換器との間に、前記減圧装置を経た冷媒をそのまま利用側熱交換器に導く第１冷媒通路と、前記減圧装置を経て、更に別の膨張弁を経た冷媒を前記圧縮機の吸込管に導く第２冷媒通路とを含み、各冷媒通路を流れる冷媒間で熱交換させて、前記第１冷媒通路を流れる冷媒を過冷却する過冷却熱交換器を備え、前記圧縮機の吸込ガス過熱度に応じて前記別の膨張弁の弁開度を制御すると共に、前記圧縮機の吐出温度が予め設定された設定値に達した場合には、前記圧縮機の吸込ガス過熱度に係わらず、前記別の膨張弁の弁開度を増大させる制御手段を備えたことを特徴とする。 In order to solve the above problems, the present invention provides a refrigeration apparatus including a compressor, a heat source side heat exchanger, a decompression device, and a use side heat exchanger, and between the decompression device and the use side heat exchanger, A first refrigerant passage that guides the refrigerant that has passed through the decompression device to the use-side heat exchanger as it is, and a second refrigerant passage that guides the refrigerant that has passed through another expansion valve to the suction pipe of the compressor through the decompression device. Including a supercooling heat exchanger that supercools the refrigerant flowing through the first refrigerant passage by exchanging heat between the refrigerants flowing through the respective refrigerant passages, and the additional expansion according to the degree of superheat of the suction gas of the compressor When the valve opening degree of the valve is controlled and the discharge temperature of the compressor reaches a preset set value, the valve of the other expansion valve is opened regardless of the degree of superheat of the suction gas of the compressor. A control means for increasing the degree is provided.

また、本発明において、前記制御手段が、前記圧縮機の吐出温度の上昇に応じて前記膨張弁の弁開度を徐々に増大させる制御を行うようにしてもよい。 In the present invention, the control means may perform control to gradually increase the valve opening of the expansion valve in accordance with an increase in the discharge temperature of the compressor.

さらに、本発明において、前記制御手段が、前記圧縮機の吸込ガス過熱度の上昇に応じて前記膨張弁の弁開度を徐々に増大させる制御を行うようにしてもよい。 Furthermore, in the present invention, the control means may perform control to gradually increase the valve opening of the expansion valve in accordance with an increase in the suction gas superheat degree of the compressor.

また、前記制御手段が、前記圧縮機の吐出温度が予め設定された温度を超えた場合は、前記膨張弁の弁開度を増大させる制御を行い、前記圧縮機の吐出温度が予め設定された温度以下であり、かつ、前記圧縮機の吸込ガス過熱度が、予め設定された過熱度を超えた場合は、前記膨張弁の弁開度を増大させる制御を行い、前記圧縮機の吐出温度が予め定められた温度以下であり、かつ、前記圧縮機の吸込ガス過熱度が予め設定された過熱度以下であった場合は、前記膨張弁の弁開度を減少させる制御を行うようにしてもよい。 Further, when the discharge temperature of the compressor exceeds a preset temperature, the control means performs control to increase the valve opening of the expansion valve, and the discharge temperature of the compressor is preset. When the temperature is equal to or lower than the temperature and the suction gas superheat degree of the compressor exceeds a preset superheat degree, control is performed to increase the valve opening of the expansion valve, and the discharge temperature of the compressor is If the suction gas superheat degree of the compressor is equal to or lower than a predetermined temperature and the superheat degree is equal to or lower than a preset superheat degree, control may be performed to reduce the valve opening of the expansion valve. Good.

本発明によれば、２重管によって、室外熱交換器から室内ユニットへ供給される冷媒を冷却するとともに、この２重管の外管を通った冷媒を圧縮機に戻すことで、圧縮機を冷却することができる。これにより、圧縮機を冷却するためのリキッド管を別途設ける必要がなくなるので、配管の簡略化を実現できる。 According to the present invention, the refrigerant supplied from the outdoor heat exchanger to the indoor unit is cooled by the double pipe, and the refrigerant passing through the outer pipe of the double pipe is returned to the compressor. Can be cooled. This eliminates the need to separately provide a liquid pipe for cooling the compressor, thereby simplifying the piping.

以下、図面を参照しつつ本発明の実施の形態について説明する。
図１において、１は空気調和装置（冷凍装置）を示す。この空気調和装置１は、複数台（２台）の室外ユニット２Ａ、２Ｂと、複数台（２台）の室内ユニット３Ａ、３Ｂとを備えている。この空気調和装置１では、室外ユニット２Ａ、２Ｂと室内ユニット３Ａ、３Ｂとを接続する冷媒配管５が、低圧ガス管６と、高圧ガス管７と、液管８とから構成され、室内ユニット３Ａ、３Ｂを同時に冷房運転若しくは暖房運転可能とし、または、これらの冷房運転（ドライ運転を含む）と暖房運転とを混在して実施可能としている。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In FIG. 1, 1 shows an air conditioning apparatus (refrigeration apparatus). The air conditioner 1 includes a plurality (two) of outdoor units 2A and 2B and a plurality (two) of indoor units 3A and 3B. In the air conditioner 1, the refrigerant pipe 5 that connects the outdoor units 2A, 2B and the indoor units 3A, 3B includes a low-pressure gas pipe 6, a high-pressure gas pipe 7, and a liquid pipe 8, and the indoor unit 3A 3B can be simultaneously operated for cooling or heating, or the cooling operation (including dry operation) and the heating operation can be mixed.

室内ユニット３Ａは、室内熱交換器（利用側熱交換器）１０と膨張弁１１とを備えて構成され、この室内熱交換器１０の一端は、膨張弁１１を介して液管８に配管接続されている。また、室内熱交換器１０の他端には、分岐管１２が接続され、この分岐管１２は、高圧ガス分岐管１２Ａと低圧ガス分岐管１２Ｂとに分岐し、一方の高圧ガス分岐管１２Ａは第１開閉弁（例えば、電磁弁）１３を介して高圧ガス管７に接続され、他方の低圧ガス分岐管１２Ｂは第２開閉弁（例えば、電磁弁）１４を介して低圧ガス管６に接続されている。また、室内ユニット３Ａには、室外熱交換器２１の出入口温度や室温を検出する温度センサ等が配置される他、これらセンサの検出結果を入力してこの室内ユニット３Ａの制御を行う室内制御装置（図示せず）を備えている。
室内ユニット３Ｂは、室内ユニット３Ａと略同一の構成であるため、同一の部分に同一の符号を付して示し、重複する説明は省略する The indoor unit 3 A includes an indoor heat exchanger (use side heat exchanger) 10 and an expansion valve 11, and one end of the indoor heat exchanger 10 is connected to the liquid pipe 8 via the expansion valve 11. Has been. A branch pipe 12 is connected to the other end of the indoor heat exchanger 10, and this branch pipe 12 branches into a high-pressure gas branch pipe 12A and a low-pressure gas branch pipe 12B. The first open / close valve (for example, electromagnetic valve) 13 is connected to the high pressure gas pipe 7, and the other low pressure gas branch pipe 12 B is connected to the low pressure gas pipe 6 via the second open / close valve (for example, electromagnetic valve) 14. Has been. The indoor unit 3A is provided with a temperature sensor or the like for detecting the inlet / outlet temperature or room temperature of the outdoor heat exchanger 21, and an indoor controller for controlling the indoor unit 3A by inputting the detection results of these sensors. (Not shown).
Since the indoor unit 3B has substantially the same configuration as the indoor unit 3A, the same portions are denoted by the same reference numerals, and redundant description is omitted.

図２は、室外ユニット２Ａの構成を拡大して示す回路図である。なお、室外ユニット２Ｂは略同様の構成であり、その説明を省略する。
室外ユニット２Ａは、能力可変型の圧縮機（ＤＣインバータ圧縮機）２０Ａと、能力一定型の圧縮機（ＡＣ圧縮機）２０Ｂ１、２０Ｂ２と、オイルセパレータ２５と、室外熱交換器（熱源側熱交換器）２１と、膨張弁（減圧装置）２６と、レシーバタンク２３等から概略構成されている。以下、各圧縮機２０Ａ、２０Ｂ１、２０Ｂ２を特に区別する必要がない場合は、圧縮機２０と表記する。 FIG. 2 is an enlarged circuit diagram showing the configuration of the outdoor unit 2A. The outdoor unit 2B has substantially the same configuration, and a description thereof is omitted.
The outdoor unit 2A includes a variable capacity compressor (DC inverter compressor) 20A, constant capacity compressors (AC compressors) 20B1 and 20B2, an oil separator 25, and an outdoor heat exchanger (heat source side heat exchange). Device) 21, an expansion valve (decompression device) 26, a receiver tank 23, and the like. Hereinafter, the compressors 20 A, 20 B 1, 20 B 2 are referred to as the compressors 20 when it is not necessary to distinguish between them.

各圧縮機２０Ａ、２０Ｂ１、２０Ｂ２は、圧縮動作時に内部が高圧となる高圧容器の圧縮機であり、一の圧縮機２０の高圧部（高圧容器内）と他の圧縮機２０の低圧部（吸込管内）とがオイル管６１で連結され、このオイル管６１にはキャピラリーチューブ（絞り）６２が設けられている。 Each of the compressors 20A, 20B1, and 20B2 is a high-pressure vessel compressor that has a high pressure inside during a compression operation. The high-pressure portion (inside the high-pressure vessel) of one compressor 20 and the low-pressure portion (suction) of another compressor 20 The oil pipe 61 is connected with an oil pipe 61, and the oil pipe 61 is provided with a capillary tube (throttle) 62.

各圧縮機２０Ａ、２０Ｂ１、２０Ｂ２は、並列接続され、各圧縮機２０Ａ、２０Ｂ１、２０Ｂ２の吸込口に共通接続された吸込管３０が、アキュムレータ２４を介して低圧ガス管６に接続される。また、各圧縮機２０Ａ、２０Ｂ１、２０Ｂ２の吐出口に接続された吐出管３１は、オイルセパレータ２５を経て延出し、２つに分岐し、一方の冷媒吐出分岐管３１Ａが高圧ガス管７に接続され、他方の冷媒吐出分岐管３１Ｂが室外熱交換器２１に接続されている。 The compressors 20A, 20B1, and 20B2 are connected in parallel, and the suction pipe 30 that is commonly connected to the suction ports of the compressors 20A, 20B1, and 20B2 is connected to the low-pressure gas pipe 6 via the accumulator 24. The discharge pipe 31 connected to the discharge port of each compressor 20A, 20B1, 20B2 extends through the oil separator 25 and branches into two, and one refrigerant discharge branch pipe 31A is connected to the high-pressure gas pipe 7. The other refrigerant discharge branch pipe 31B is connected to the outdoor heat exchanger 21.

ここで、上記冷媒吐出分岐管３１Ｂには、切換弁４０が設けられ、この切換弁４０が開くと、圧縮機２０の吐出冷媒が、室外熱交換器２１に供給される。
上記切換弁４０と室外熱交換器２１の間には、一つのポートＡが塞がれた、四方弁４１が設けられ、この四方弁４１は、室外熱交換器２１の一端と、切換弁４０につながる管路３１Ｂとを連通し、或いは、室外熱交換器２１の一端と、圧縮機２０の吸込管３０につながる管路３２とを連通する。 Here, the refrigerant discharge branch pipe 31B is provided with a switching valve 40. When the switching valve 40 is opened, the refrigerant discharged from the compressor 20 is supplied to the outdoor heat exchanger 21.
Between the switching valve 40 and the outdoor heat exchanger 21, there is provided a four-way valve 41 in which one port A is blocked. The four-way valve 41 includes one end of the outdoor heat exchanger 21 and the switching valve 40. Or a pipe 32 connected to one end of the outdoor heat exchanger 21 and a suction pipe 30 of the compressor 20.

補助冷却回路（過冷却熱交換器）２８は、いわゆる２重管式熱交換器であり、内管には、レシーバタンク２３と液管８とに接続される配管（第１冷媒通路）３３が連通し、外管には、配管３３から分岐して冷媒吸込管３０に接続される分岐管（第２冷媒通路）３４が連通する。分岐管３４には、後述する電動膨張弁（別の膨張弁）２９が配設される。 The auxiliary cooling circuit (supercooling heat exchanger) 28 is a so-called double pipe heat exchanger, and a pipe (first refrigerant passage) 33 connected to the receiver tank 23 and the liquid pipe 8 is provided in the inner pipe. The branch pipe (second refrigerant passage) 34 branched from the pipe 33 and connected to the refrigerant suction pipe 30 communicates with the outer pipe. The branch pipe 34 is provided with an electric expansion valve (another expansion valve) 29 described later.

後述するように、室内ユニット３Ａ、３Ｂの冷房運転に対応して、室外ユニット２Ａにおいて圧縮機２０から吐出された冷媒が室外熱交換器２１を通り、液管８を介して室内ユニット３Ａ、３Ｂに流れる場合、補助冷却回路２８の内管には、レシーバタンク２３から液管８に流れる冷媒が通る。一方、補助冷却回路２８の外管には電動膨張弁２９を通って膨張した冷媒が通り、内管を通る冷媒との間で熱交換され、内管を通る冷媒が冷却される。 As will be described later, in response to the cooling operation of the indoor units 3A and 3B, the refrigerant discharged from the compressor 20 in the outdoor unit 2A passes through the outdoor heat exchanger 21 and passes through the liquid pipe 8 to the indoor units 3A and 3B. , The refrigerant flowing from the receiver tank 23 to the liquid pipe 8 passes through the inner pipe of the auxiliary cooling circuit 28. On the other hand, the refrigerant expanded through the electric expansion valve 29 passes through the outer pipe of the auxiliary cooling circuit 28, heat exchange is performed with the refrigerant passing through the inner pipe, and the refrigerant passing through the inner pipe is cooled.

これにより、レシーバタンク２３から液管８に流れる冷媒が冷却されるので、例えばこの冷媒が気体と液体の２相であった場合、冷却により液体１相となって、液管８を通る際の圧力損失が減少し、ＣＯＰの改善に寄与する。これは、補助冷却回路２８の冷却容量を、レシーバタンク２３から液管８に流れる冷媒が液体１相となるよう設計すれば、容易に実現できる。 As a result, the refrigerant flowing from the receiver tank 23 to the liquid pipe 8 is cooled. For example, when the refrigerant has two phases of gas and liquid, the liquid becomes one phase by cooling and passes through the liquid pipe 8. Pressure loss is reduced, contributing to improvement of COP. This can be easily realized if the cooling capacity of the auxiliary cooling circuit 28 is designed so that the refrigerant flowing from the receiver tank 23 to the liquid pipe 8 is in a single liquid phase.

また、補助冷却回路２８の外管を通った冷媒は、冷媒配管（第２冷媒通路）３５を介して圧縮機２０の冷媒吸込管３０に戻される。これにより、圧縮機２０の吸込口に低温の冷媒が流入するので、圧縮機２０が冷却される。
電動膨張弁２９は、ステッピングモータ（図示略）を備え、このステッピングモータの動作により開閉される膨張弁である。電動膨張弁２９が備えるステッピングモータは、室外制御装置１００から入力されるパルスに従って所定角度ずつ回転し、電動膨張弁２９の弁開度を全閉から全開まで調節する。この電動膨張弁２９の弁開度が調節されることにより、分岐管３４から補助冷却回路２８の外管に流れる冷媒の量が調節される。 The refrigerant that has passed through the outer pipe of the auxiliary cooling circuit 28 is returned to the refrigerant suction pipe 30 of the compressor 20 through the refrigerant pipe (second refrigerant passage) 35. Thereby, since a low-temperature refrigerant | coolant flows in into the suction inlet of the compressor 20, the compressor 20 is cooled.
The electric expansion valve 29 includes a stepping motor (not shown), and is an expansion valve that is opened and closed by the operation of the stepping motor. The stepping motor included in the electric expansion valve 29 rotates by a predetermined angle according to a pulse input from the outdoor control device 100, and adjusts the valve opening degree of the electric expansion valve 29 from fully closed to fully open. By adjusting the valve opening degree of the electric expansion valve 29, the amount of refrigerant flowing from the branch pipe 34 to the outer pipe of the auxiliary cooling circuit 28 is adjusted.

オイルセパレータ２５には、オイルセパレータ２５に溜められたオイル量が所定量以上の場合に、余剰のオイル（潤滑油）を圧縮機２０の吸込管３０に戻す冷媒戻し管４５と、当該オイルセパレータ２５と他の室外ユニット２Ｂのオイルセパレータ２５とを接続するためのオイルバランス管４６とが接続される。冷媒戻し管４５にはキャピラリーチューブ３６が配設され、オイルバランス管４６にはキャピラリーチューブ３７、バランス弁４２、および逆止弁４８が直列に配設されている。 The oil separator 25 includes a refrigerant return pipe 45 that returns excess oil (lubricating oil) to the suction pipe 30 of the compressor 20 when the amount of oil stored in the oil separator 25 is a predetermined amount or more, and the oil separator 25. And an oil balance pipe 46 for connecting the oil separator 25 of the other outdoor unit 2B. A capillary tube 36 is disposed in the refrigerant return pipe 45, and a capillary tube 37, a balance valve 42, and a check valve 48 are disposed in series in the oil balance pipe 46.

オイルバランス管４６は、図１に示すように、オイル管４７を介して他の室外ユニット２Ｂのオイルセパレータ２５と接続されると共に、このオイルバランス管４６から分岐する分岐管４５Ａを介して冷媒戻し管４５に接続される。この分岐管４５Ａには、開閉弁４４が設けられる。このため、オイルバランス管４６の開閉弁４２が開き、オイル分岐管４５Ａの開閉弁４４が閉じると、オイルセパレータ２５に貯留されたオイルが他の室外ユニット２Ｂに供給される。また、開閉弁４２が閉じ、開閉弁４４が開くと、他の室外ユニット２Ｂから供給されたオイルが、逆止弁４８により止められてオイル分岐管４５Ａへ流れ、分岐管４５Ａを介して冷媒戻し管４５に供給され、これによって、室外ユニット２Ａ、２Ｂ間をオイルが行き来可能に構成されている。 As shown in FIG. 1, the oil balance pipe 46 is connected to the oil separator 25 of another outdoor unit 2B via an oil pipe 47, and returns to the refrigerant via a branch pipe 45A branched from the oil balance pipe 46. Connected to tube 45. The branch pipe 45A is provided with an on-off valve 44. For this reason, when the on-off valve 42 of the oil balance pipe 46 is opened and the on-off valve 44 of the oil branch pipe 45A is closed, the oil stored in the oil separator 25 is supplied to the other outdoor unit 2B. When the on-off valve 42 is closed and the on-off valve 44 is opened, the oil supplied from the other outdoor unit 2B is stopped by the check valve 48 and flows into the oil branch pipe 45A, and the refrigerant is returned through the branch pipe 45A. The oil is supplied to the pipe 45 so that the oil can go back and forth between the outdoor units 2A and 2B.

さらに、オイルバランス管４６には、バランス弁４２と逆止弁４８との間において、冷媒吐出分岐管３１Ａから分岐する冷媒吐出分岐管３１Ｃが接続される。冷媒吐出分岐管３１Ｃにはバイパス弁４３が配設され、このバイパス弁４３が開くと、冷媒吐出分岐管３１Ｃからオイルバランス管４６に高圧の冷媒が流入する。上述のようにオイルバランス管４６の開閉弁４２を開き、オイル分岐管４５Ａの開閉弁４４を閉じて、オイルセパレータ２５内のオイルを他の室外ユニット２Ｂに供給する場合に、バイパス弁４３が開くと、高圧の冷媒によってオイルバランス管４６内のオイルがオイル管４７へ押し流され、他の室外ユニット２Bに速やかにオイルが供給される。 Further, a refrigerant discharge branch pipe 31C branched from the refrigerant discharge branch pipe 31A is connected to the oil balance pipe 46 between the balance valve 42 and the check valve 48. A bypass valve 43 is disposed in the refrigerant discharge branch pipe 31C. When the bypass valve 43 is opened, a high-pressure refrigerant flows from the refrigerant discharge branch pipe 31C into the oil balance pipe 46. As described above, when the on-off valve 42 of the oil balance pipe 46 is opened, the on-off valve 44 of the oil branch pipe 45A is closed, and the oil in the oil separator 25 is supplied to the other outdoor unit 2B, the bypass valve 43 is opened. Then, the oil in the oil balance pipe 46 is forced to flow into the oil pipe 47 by the high-pressure refrigerant, and the oil is quickly supplied to the other outdoor unit 2B.

また、レシーバタンク２３の上部には分岐管５１の一端が接続される。分岐管５１の他端は二股に分岐して、その一方は、開閉弁５０およびキャピラリーチューブ５２を介して低圧ガス管６に接続され、他方は、キャピラリーチューブ５４および開閉弁５３を介して、冷媒吐出分岐管３１Ａに接続される。レシーバタンク２３の内部には気体の冷媒と液体の冷媒とが存在するが、レシーバタンク２３に分岐管５１が接続される部分は気体の冷媒に接する位置となっている。 One end of the branch pipe 51 is connected to the upper part of the receiver tank 23. The other end of the branch pipe 51 is bifurcated, one of which is connected to the low-pressure gas pipe 6 via the on-off valve 50 and the capillary tube 52, and the other is connected to the refrigerant via the capillary tube 54 and the on-off valve 53. Connected to the discharge branch pipe 31A. A gas refrigerant and a liquid refrigerant exist inside the receiver tank 23, but a portion where the branch pipe 51 is connected to the receiver tank 23 is in a position in contact with the gas refrigerant.

開閉弁５３が開放されると、冷媒吐出分岐管３１Ａからの高圧の冷媒がキャピラリーチューブ５４を介してレシーバタンク２３に流入し、レシーバタンク２３内の冷媒が液管８に向けて押し出される。例えば、室内ユニット３Ａ、３Ｂにおいて冷媒不足が生じた場合に、開閉弁５３を開放すると、レシーバタンク２３内に貯留された冷媒が室内ユニット３Ａ、３Ｂに供給され、冷媒不足を解消できる。 When the on-off valve 53 is opened, high-pressure refrigerant from the refrigerant discharge branch pipe 31 A flows into the receiver tank 23 via the capillary tube 54, and the refrigerant in the receiver tank 23 is pushed out toward the liquid pipe 8. For example, when the refrigerant shortage occurs in the indoor units 3A and 3B, if the on-off valve 53 is opened, the refrigerant stored in the receiver tank 23 is supplied to the indoor units 3A and 3B, and the refrigerant shortage can be solved.

一方、開閉弁５０が開放されると、レシーバタンク２３内の気体の冷媒が分岐管５１を介して低圧ガス管６に流出する。例えば、空気調和装置１の運転を停止する際に、空気調和装置１を循環する冷媒をレシーバタンク２３に集めようとする場合、キャピラリーチューブ５２を開放すると、レシーバタンク２３内の高圧の冷媒ガスが低圧ガス管６に供給され、室内ユニット３Ａ、３Ｂ内の冷媒が室外ユニット２Ａ、２Ｂに向けて押し流されるので、冷媒をレシーバタンク２３に集めることができる。 On the other hand, when the on-off valve 50 is opened, the gaseous refrigerant in the receiver tank 23 flows out to the low-pressure gas pipe 6 through the branch pipe 51. For example, when the operation of the air conditioner 1 is stopped, when the refrigerant circulating in the air conditioner 1 is to be collected in the receiver tank 23, when the capillary tube 52 is opened, the high-pressure refrigerant gas in the receiver tank 23 is increased. Since the refrigerant in the indoor units 3A, 3B is supplied to the low-pressure gas pipe 6 and is pushed toward the outdoor units 2A, 2B, the refrigerant can be collected in the receiver tank 23.

室外ユニット２Ａにおいて、各圧縮機２０Ａ、２０Ｂ１、２０Ｂ２には、それぞれ、吐出ガスの圧力を検出する圧力センサＳＢ１、ＳＢ２、ＳＢ３と、吐出ガスの温度を検出する温度センサＳＰ１、ＳＰ２、ＳＰが配設される。また、冷媒吸込管３０には、圧縮機２０の吸込ガス圧力を検出する圧力センサＳＡ１と、吸込ガス温度を検出するＳＰ４とが配設される。さらに、室外熱交換器２１には、室外熱交換器２１の出入口温度を検出する温度センサＳＯ１、ＳＯ２が配設される。これらの圧力センサおよび温度センサは、いずれも室外制御装置１００に接続され、室外制御装置１００は、これら各センサにより検出された圧力または温度を取得する。なお、室外ユニット２Ａにおいて、さらに別の圧力センサまたは温度センサを備えることは勿論可能である。 In the outdoor unit 2A, each of the compressors 20A, 20B1, and 20B2 includes pressure sensors SB1, SB2, and SB3 that detect the pressure of the discharge gas, and temperature sensors SP1, SP2, and SP that detect the temperature of the discharge gas. Established. The refrigerant suction pipe 30 is provided with a pressure sensor SA1 for detecting the suction gas pressure of the compressor 20 and SP4 for detecting the suction gas temperature. Furthermore, the outdoor heat exchanger 21 is provided with temperature sensors SO1 and SO2 for detecting the inlet / outlet temperature of the outdoor heat exchanger 21. Both of these pressure sensors and temperature sensors are connected to the outdoor control device 100, and the outdoor control device 100 acquires the pressure or temperature detected by these sensors. Of course, the outdoor unit 2A can further include another pressure sensor or temperature sensor.

１００は、室外制御装置である。
この空気調和装置１は、図示を省略したリモートコントローラを備え、室外ユニット２Ａ、２Ｂのいずれかの室外制御装置１００が、リモートコントローラを介して入力したユーザ指示等に応じて、他の室外制御装置１００や室内制御装置と通信し、この空気調和装置１全体の運転制御を行う。具体的には、室外制御装置１００は、ユーザにより指示された動作を実現するため、自ユニットが備える圧力センサ、温度センサにより検出された圧力および温度に基づき、各種弁を開閉・切換する制御を行う。 Reference numeral 100 denotes an outdoor control device.
The air conditioner 1 includes a remote controller (not shown), and the outdoor control device 100 of any of the outdoor units 2A and 2B receives another outdoor control device according to a user instruction or the like input via the remote controller. It communicates with 100 and an indoor control apparatus, and performs operation control of this air conditioning apparatus 1 whole. Specifically, the outdoor control device 100 performs control for opening / closing / switching various valves based on the pressure and temperature detected by the pressure sensor and the temperature sensor of the own unit in order to realize the operation instructed by the user. Do.

全ての室内ユニット３Ａ、３Ｂを同時に冷房運転する場合、各室外ユニット２Ａ、２Ｂでは、切換弁４０が開くと共に四方弁４１が切換制御され、また、各室内ユニット３Ａ、３Ｂでは第１開閉弁１３が閉じ、第２開閉弁１４が開く。この場合、圧縮機２０の吐出冷媒が、オイルセパレータ２５を介して室外熱交換器２１に供給され、ここで放熱・凝縮して液冷媒となり、レシーバタンク２３及び補助冷却回路２８を経て液管８に供給される。
そして、室内ユニット３Ａ、３Ｂにおいては、液管８を介して液冷媒が膨張弁１１を介して室内熱交換器１０に供給され、ここで吸熱・蒸発し、低温低圧のガス冷媒となり、第２開閉弁１４を介して低圧ガス管６に供給される。
この低圧ガス管６に供給されたガス冷媒は、室外ユニット２Ａ、２Ｂの吸込管３０を介して圧縮機２０で再び圧縮される。これによって、全ての室内ユニット３Ａ、３Ｂで同時に冷房運転が可能になる。 When all the indoor units 3A, 3B are simultaneously cooled, the switching valve 40 is opened in each outdoor unit 2A, 2B and the four-way valve 41 is controlled to be switched. In each indoor unit 3A, 3B, the first on-off valve 13 is controlled. Is closed and the second on-off valve 14 is opened. In this case, the refrigerant discharged from the compressor 20 is supplied to the outdoor heat exchanger 21 via the oil separator 25, where it dissipates and condenses to become liquid refrigerant, and passes through the receiver tank 23 and the auxiliary cooling circuit 28 to the liquid pipe 8. To be supplied.
In the indoor units 3A and 3B, the liquid refrigerant is supplied to the indoor heat exchanger 10 via the liquid pipe 8 via the expansion valve 11, where it absorbs and evaporates to become a low-temperature and low-pressure gas refrigerant. The gas is supplied to the low-pressure gas pipe 6 through the on-off valve 14.
The gas refrigerant supplied to the low-pressure gas pipe 6 is compressed again by the compressor 20 through the suction pipes 30 of the outdoor units 2A and 2B. As a result, all the indoor units 3A and 3B can simultaneously perform the cooling operation.

一方、全ての室内ユニット３Ａ、３Ｂを同時に暖房運転する場合、各室外ユニット２Ａ、２Ｂでは、切換弁４０が閉じると共に四方弁４１が切換制御され、各室内ユニット３Ａ、３Ｂでは第１開閉弁１３が開き、第２開閉弁１４が閉じる。この場合、圧縮機２０が吐出した高温高圧のガス冷媒が、オイルセパレータ２５を介して高圧ガス管７に供給される。そして、室内ユニット３Ａ、３Ｂにおいては、高圧ガス管７を介してガス冷媒が室内熱交換器１０に供給され、ここで、放熱・凝縮して液冷媒となった後、膨張弁１１を介して液管８に供給される。この液管８に供給された液冷媒は、室外ユニット２Ａ、２Ｂの冷媒配管３３及びレシーバタンク２３を介して室外熱交換器２１に供給され、ここで、吸熱・蒸発し、ここで低温低圧のガス冷媒となり、吸込管３０を介して圧縮機２０で再び圧縮される。これによって、全ての室内ユニット３Ａ、３Ｂで同時に暖房運転が可能になる。 On the other hand, when all the indoor units 3A and 3B are simultaneously operated for heating, the switching valve 40 is closed and the four-way valve 41 is switched in each of the outdoor units 2A and 2B, and the first on-off valve 13 is controlled in each of the indoor units 3A and 3B. Opens and the second on-off valve 14 closes. In this case, the high-temperature and high-pressure gas refrigerant discharged from the compressor 20 is supplied to the high-pressure gas pipe 7 through the oil separator 25. In the indoor units 3A and 3B, the gas refrigerant is supplied to the indoor heat exchanger 10 through the high-pressure gas pipe 7, where after the heat is radiated and condensed to become liquid refrigerant, the refrigerant is passed through the expansion valve 11. It is supplied to the liquid pipe 8. The liquid refrigerant supplied to the liquid pipe 8 is supplied to the outdoor heat exchanger 21 through the refrigerant pipes 33 and the receiver tank 23 of the outdoor units 2A and 2B, where it absorbs heat and evaporates, where It becomes a gas refrigerant and is compressed again by the compressor 20 through the suction pipe 30. Thereby, the heating operation can be simultaneously performed in all the indoor units 3A and 3B.

また、暖房運転と冷房運転の混在運転を行う場合、例えば、室内ユニット３Ａを暖房運転し、室内ユニット３Ｂを冷房運転する場合、室外ユニット２Ａ、２Ｂが上記同時暖房運転の場合と同様に制御される一方、室内ユニット３Ａにおいては、第１開閉弁１３が閉じ、第２開閉弁１４が開き、室内ユニット３Ｂにおいては、第１開閉弁１３が開き、第２開閉弁１５が閉じる。この場合、各室外ユニット２Ａ、２Ｂから高温高圧のガス冷媒が高圧ガス管７に供給され、室内ユニット３Ａにおいては、高圧ガス管７を介してガス冷媒が室内熱交換器１０に供給され、ここで放熱・凝縮して液冷媒となった後、膨張弁１１を介して液管８に供給される。この液管８に供給された液冷媒の一部は室外ユニット２Ａ、２Ｂへ戻り、室外熱交換器２１で吸熱・蒸発し、低温低圧のガス冷媒となる。 Further, when performing a mixed operation of heating operation and cooling operation, for example, when the indoor unit 3A is operated for heating and the indoor unit 3B is operated for cooling, the outdoor units 2A and 2B are controlled in the same manner as in the above-mentioned simultaneous heating operation. On the other hand, in the indoor unit 3A, the first on-off valve 13 is closed and the second on-off valve 14 is opened, and in the indoor unit 3B, the first on-off valve 13 is opened and the second on-off valve 15 is closed. In this case, high-temperature and high-pressure gas refrigerant is supplied from the outdoor units 2A and 2B to the high-pressure gas pipe 7, and in the indoor unit 3A, gas refrigerant is supplied to the indoor heat exchanger 10 via the high-pressure gas pipe 7. After being radiated / condensed to form a liquid refrigerant, it is supplied to the liquid pipe 8 via the expansion valve 11. A part of the liquid refrigerant supplied to the liquid pipe 8 returns to the outdoor units 2A and 2B, absorbs heat and evaporates in the outdoor heat exchanger 21, and becomes a low-temperature and low-pressure gas refrigerant.

一方、液管８に供給された液冷媒の残りは、室内ユニット３Ｂの室内熱交換器１０に供給され、ここで吸熱・蒸発し、低温低圧のガス冷媒となった後、第２開閉弁１４を介して低圧ガス管６に供給される。
そして、低圧ガス管６に供給された冷媒は、室外熱交換器２１を経た上記ガス冷媒と共に、吸込管３０を介して圧縮機２０で再び圧縮される。これによって、室内ユニット３Ａ、３Ｂ毎に暖房運転と冷房運転とが可能になる。 On the other hand, the remainder of the liquid refrigerant supplied to the liquid pipe 8 is supplied to the indoor heat exchanger 10 of the indoor unit 3B, where it absorbs heat and evaporates to become a low-temperature and low-pressure gas refrigerant, and then the second on-off valve 14. Is supplied to the low-pressure gas pipe 6.
The refrigerant supplied to the low-pressure gas pipe 6 is compressed again by the compressor 20 through the suction pipe 30 together with the gas refrigerant passed through the outdoor heat exchanger 21. Thereby, heating operation and cooling operation can be performed for each of the indoor units 3A and 3B.

ここで、室外ユニット２Ａにおいて、室内ユニット３Ａ、３Ｂの冷房運転に対応した動作をする場合、すなわち、切換弁４０が開くと共に四方弁４１が切換制御され、圧縮機２０の吐出冷媒が室外熱交換器２１およびレシーバタンク２３を経て液管８に供給される場合における、電動膨張弁２９の制御について説明する。 Here, in the outdoor unit 2A, when the operation corresponding to the cooling operation of the indoor units 3A and 3B is performed, that is, the switching valve 40 is opened and the four-way valve 41 is switched and the refrigerant discharged from the compressor 20 is exchanged with the outdoor heat. The control of the electric expansion valve 29 when it is supplied to the liquid pipe 8 via the container 21 and the receiver tank 23 will be described.

図３は、室外制御装置１００による電動膨張弁２９の弁開度制御に係る動作を示すフローチャートである。
この図３に示す動作に先立って、室外ユニット２Ａにおいては、予め、圧縮機２０の吐出温度および圧縮機２０の吸込ガスの過熱度について設定が行われ、室外制御装置１００は、設定された値を記憶する。 FIG. 3 is a flowchart showing an operation related to the valve opening degree control of the electric expansion valve 29 by the outdoor control device 100.
Prior to the operation shown in FIG. 3, in the outdoor unit 2 A, the discharge temperature of the compressor 20 and the superheat degree of the suction gas of the compressor 20 are set in advance, and the outdoor control device 100 sets the set values. Remember.

室外制御装置１００は、まず、温度センサＳＰ１、ＳＰ２、ＳＰ３により検出される圧縮機２０の吐出温度を取得し、圧縮機２０の吐出ガスの温度が、予め設定された値を超えたか否かを判別する（ステップＳ１）。このステップＳ１で、室外制御装置１００は、温度センサＳＢ１、ＳＢ２、ＳＢ３のうちいずれか一つにより検出された温度が設定値を超えていた場合は、吐出ガスの温度が設定値を超えたと判別する。このため、ステップＳ１では、３つの圧縮機２０Ａ、２０Ｂ１、２０Ｂ２のうち、少なくとも１台の圧縮機における吐出ガス温度が設定値を超えた場合、Ｙｅｓとなる。 The outdoor control device 100 first acquires the discharge temperature of the compressor 20 detected by the temperature sensors SP1, SP2, and SP3, and determines whether or not the temperature of the discharge gas of the compressor 20 exceeds a preset value. It discriminate | determines (step S1). In step S1, the outdoor control device 100 determines that the temperature of the discharge gas has exceeded the set value when the temperature detected by any one of the temperature sensors SB1, SB2, and SB3 exceeds the set value. To do. For this reason, in step S1, when the discharge gas temperature in at least one compressor out of the three compressors 20A, 20B1, and 20B2 exceeds the set value, Yes.

ここで、圧縮機２０の吐出温度が設定値を超えていた場合（ステップＳ１；Ｙｅｓ）、室外制御装置１００は電動膨張弁２９を制御して、現在の状態よりもさらに開かせる（ステップＳ２）。このステップＳ２で、室外制御装置１００は、電動膨張弁２９が備えるステッピングモータ（図示略）に対して所定数のパルスを送出し、電動膨張弁２９を開く方向に、所定の角度だけステッピングモータを回転させる。これにより、電動膨張弁２９の弁開度が、現在の状態よりも増大する。
このステップＳ２の後、室外制御装置１００はステップＳ１の動作に戻る。 Here, when the discharge temperature of the compressor 20 exceeds the set value (step S1; Yes), the outdoor control device 100 controls the electric expansion valve 29 so that it opens more than the current state (step S2). . In step S2, the outdoor control device 100 sends a predetermined number of pulses to a stepping motor (not shown) provided in the electric expansion valve 29, and opens the stepping motor by a predetermined angle in the direction of opening the electric expansion valve 29. Rotate. Thereby, the valve opening degree of the electric expansion valve 29 is increased from the current state.
After this step S2, the outdoor control device 100 returns to the operation of step S1.

また、圧縮機２０の吐出温度が設定値を超えていなかった場合（ステップＳ１；Ｎｏ）、室外制御装置１００は、圧縮機２０の吸込ガスの過熱度が、予め設定された値を超えたか否かを判別する（ステップＳ３）。このステップＳ３で、室外制御装置１００は、圧力センサＳＡ１により検出された、圧縮機２０の吸込ガスの圧力をもとに飽和温度を算出し、算出した飽和温度と、温度センサＳＰ４により検出された実際の吸込ガスの温度との温度差に基づいて、吸込ガスの過熱度を求める。そして、求めた過熱度が設定値を超えているか否かを判別する。 When the discharge temperature of the compressor 20 does not exceed the set value (step S1; No), the outdoor control device 100 determines whether the superheat degree of the suction gas of the compressor 20 exceeds a preset value. Is determined (step S3). In step S3, the outdoor control device 100 calculates a saturation temperature based on the pressure of the suction gas of the compressor 20 detected by the pressure sensor SA1, and the detected saturation temperature and the temperature sensor SP4 detect the saturation temperature. Based on the temperature difference from the actual suction gas temperature, the degree of superheat of the suction gas is determined. And it is discriminate | determined whether the calculated | required superheat degree exceeds the setting value.

ここで、吸込ガスの過熱度が設定値を超えていた場合（ステップＳ３；Ｙｅｓ）、室外制御装置１００は、ステップＳ２に移行して、電動膨張弁２９を開く制御を行う。
また、吸込ガスの過熱度が設定値を超えていなかった場合には（ステップＳ３；Ｎｏ）、室外制御装置１００は、電動膨張弁２９を、現在の状態よりもさらに閉じる制御を行う（ステップＳ４）。このステップＳ４で、室外制御装置１００は、電動膨張弁２９が備えるステッピングモータ（図示略）に対して所定数のパルスを送出し、電動膨張弁２９を閉じる方向に、所定の角度だけステッピングモータを回転させる。これにより、電動膨張弁２９の弁開度が、現在の状態よりも減少する。
このステップＳ４の後、室外制御装置１００はステップＳ１の動作に戻る。 Here, if the superheat degree of the suction gas exceeds the set value (step S3; Yes), the outdoor control device 100 proceeds to step S2 and performs control to open the electric expansion valve 29.
When the superheat degree of the suction gas does not exceed the set value (step S3; No), the outdoor control device 100 performs control to further close the electric expansion valve 29 than the current state (step S4). ). In step S4, the outdoor control device 100 sends a predetermined number of pulses to a stepping motor (not shown) provided in the electric expansion valve 29, and closes the electric expansion valve 29 to move the stepping motor by a predetermined angle. Rotate. Thereby, the valve opening degree of the electric expansion valve 29 is reduced from the current state.
After step S4, the outdoor control device 100 returns to the operation of step S1.

図３に示す動作によれば、圧縮機２０の吸込ガスの過熱度が設定値以下の場合、電動膨張弁２９の弁開度を減少させる制御が行われ、圧縮機２０の吸込ガスの過熱度が設定値を超えた場合は、電動膨張弁２９の弁開度を増大させる制御が行われるので、液圧縮を起こす可能性が高まらない範囲において、圧縮機２０に冷媒が供給される。さらに、圧縮機２０の吐出温度が設定値よりも高い場合には、圧縮機２０の吸込ガスの過熱度に係わらず電動膨張弁２９の弁開度を増大させる制御が行われ、圧縮機２０が冷却される。
また、空気調和装置１の運転中に図３に示す動作を繰り返し実行することで、室外制御装置１００により、圧縮機２０の吐出温度の上昇に応じて電動膨張弁２９の弁開度を徐々に増大させ、また、圧縮機２０の吸込ガス過熱度の上昇に応じて電動膨張弁２９の弁開度を徐々に増大させるように、制御が行われる。 According to the operation shown in FIG. 3, when the superheat degree of the suction gas of the compressor 20 is equal to or less than the set value, the valve opening degree of the electric expansion valve 29 is controlled, and the superheat degree of the suction gas of the compressor 20 is controlled. When the value exceeds the set value, control to increase the valve opening degree of the electric expansion valve 29 is performed, so that the refrigerant is supplied to the compressor 20 within a range where the possibility of causing liquid compression does not increase. Furthermore, when the discharge temperature of the compressor 20 is higher than the set value, control is performed to increase the valve opening degree of the electric expansion valve 29 regardless of the degree of superheat of the suction gas of the compressor 20, and the compressor 20 is To be cooled.
Further, by repeatedly executing the operation shown in FIG. 3 during the operation of the air conditioner 1, the outdoor control device 100 gradually increases the valve opening degree of the electric expansion valve 29 in accordance with the increase in the discharge temperature of the compressor 20. Control is performed so that the valve opening degree of the electric expansion valve 29 is gradually increased as the suction gas superheat degree of the compressor 20 increases.

以上のように、本発明の実施の形態にかかる空気調和装置１によれば、室外ユニット２Ａ、２Ｂにおいて、室外熱交換器２１から膨張弁２６を経て吐出される冷媒をそのまま室内ユニット３Ａ、３Ｂが備える室内熱交換器１０に導く配管３３と、室外熱交換器２１から膨張弁２６を経て吐出される冷媒を、電動膨張弁２９を経て圧縮機２０の吸込口に導く分岐管３４および冷媒配管３５とに連通する補助冷却回路２８において、各冷媒通路を流れる冷媒間で熱交換させる構成として、室外制御装置１００により、圧縮機２０の吸込ガス過熱度に応じて電動膨張弁２９の弁開度を制御すると共に、圧縮機２０の吐出温度が予め設定された設定値に達した場合には、圧縮機２０の吸込ガス過熱度に係わらず、電動膨張弁２９の弁開度を増大させるので、膨張弁２６から液管８を介して室内ユニット３Ａ、３Ｂへ流れる冷媒を過冷却するとともに、圧縮機２０の吸込口に冷媒を供給して圧縮機２０を冷却することができる。さらに、電動膨張弁２９の弁開度を圧縮機２０の吸込ガスの過熱度に基づいて制御することで、例えば、圧縮機２０の吸込ガスの過熱度が低い場合、すなわち、圧縮機２０が液圧縮を起こす可能性が高い場合に、電動膨張弁２９の弁開度を減少させて、液圧縮を防止できる。
これにより、ＣＯＰの増大を図るとともに、圧縮機２０を効果的に冷却することが可能である。さらに、従来用いられてきた圧縮機２０を冷却するためのリキッド管を備える必要がなく、配管類の簡素化を図ることが可能である。 As described above, according to the air conditioner 1 according to the embodiment of the present invention, in the outdoor units 2A and 2B, the refrigerant discharged from the outdoor heat exchanger 21 via the expansion valve 26 is directly used as the indoor units 3A and 3B. A pipe 33 that leads to the indoor heat exchanger 10, a branch pipe 34 that leads the refrigerant discharged from the outdoor heat exchanger 21 via the expansion valve 26 to the suction port of the compressor 20 via the electric expansion valve 29, and refrigerant pipe In the auxiliary cooling circuit 28 that communicates with the refrigerant 35, the outdoor control device 100 has a valve opening degree of the electric expansion valve 29 according to the degree of superheat of the suction gas of the compressor 20. When the discharge temperature of the compressor 20 reaches a preset set value, the valve opening degree of the electric expansion valve 29 is increased regardless of the degree of superheat of the suction gas of the compressor 20. In, it is possible to cool the indoor units 3A from the expansion valve 26 via the liquid pipe 8, the refrigerant flowing into the 3B while subcooling, the compressor 20 supplies refrigerant to the suction port of the compressor 20. Further, by controlling the valve opening degree of the electric expansion valve 29 based on the degree of superheat of the suction gas of the compressor 20, for example, when the degree of superheat of the suction gas of the compressor 20 is low, that is, the compressor 20 is liquid. When the possibility of causing compression is high, the valve opening degree of the electric expansion valve 29 can be reduced to prevent liquid compression.
As a result, the COP can be increased and the compressor 20 can be effectively cooled. Furthermore, it is not necessary to provide a liquid pipe for cooling the compressor 20 that has been conventionally used, and the piping can be simplified.

また、図３を参照して説明したように、室外制御装置１００により、温度センサＳＰ１、ＳＰ２、ＳＰ３により検出される圧縮機２０の吐出温度の上昇に基づいて、電動膨張弁２９の弁開度が徐々に増大するように電動膨張弁２９を制御するので、圧縮機２０の過熱状態に応じた量の冷媒を圧縮機２０に供給し、圧縮機２０を効果的に、かつ十分に冷却することができる。 Further, as described with reference to FIG. 3, the valve opening degree of the electric expansion valve 29 is determined based on the increase in the discharge temperature of the compressor 20 detected by the outdoor control device 100 by the temperature sensors SP1, SP2, and SP3. Since the electric expansion valve 29 is controlled so as to gradually increase, an amount of refrigerant corresponding to the overheated state of the compressor 20 is supplied to the compressor 20 to effectively and sufficiently cool the compressor 20. Can do.

さらに、図３を参照して説明したように、室外制御装置１００により、圧力センサＳＡ１により検出される吸込ガスの圧力から飽和温度を算出し、算出した飽和温度と、温度センサＳＰ４により検出される吸込ガスの温度とをもとに吸込ガスの過熱度を求め、求めた過熱度の上昇に応じて電動膨張弁２９の弁開度が徐々に増大するよう電動膨張弁２９を制御するので、多量の冷媒が冷媒配管３５から圧縮機２０に供給される状態で、圧縮機２０が液圧縮を起こす可能性が高くなると、電動膨張弁２９の弁開度が減少する。これにより、圧縮機２０における液圧縮の発生を確実に防止し、効果的に圧縮機２０を冷却できる。 Furthermore, as described with reference to FIG. 3, the outdoor control device 100 calculates the saturation temperature from the pressure of the suction gas detected by the pressure sensor SA1, and the detected saturation temperature and the temperature sensor SP4 detect the saturation temperature. Since the superheat degree of the suction gas is obtained based on the temperature of the suction gas, and the electric expansion valve 29 is controlled so that the valve opening degree of the electric expansion valve 29 gradually increases as the obtained superheat degree rises, In a state where the refrigerant is supplied from the refrigerant pipe 35 to the compressor 20, the valve opening degree of the electric expansion valve 29 decreases when the possibility that the compressor 20 causes liquid compression becomes high. Thereby, generation | occurrence | production of the liquid compression in the compressor 20 can be prevented reliably, and the compressor 20 can be cooled effectively.

具体的には、室外制御装置１００は、圧縮機２０の吐出温度が予め設定された温度を超えた場合は、電動膨張弁２９の弁開度を増大させる制御を行い、圧縮機２０の吐出温度が予め設定された値以下であり、かつ、圧縮機２０の吸込ガスの過熱度が、予め設定された値を超えた場合は、電動膨張弁２９の弁開度を増大させる制御を行い、圧縮機２０の吐出温度が予め定められた値以下であり、かつ、圧縮機２０の吸込ガスの過熱度が予め設定された値以下であった場合は、電動膨張弁２９の弁開度を減少させる制御を行う。これにより、圧縮機２０を、液圧縮を防止しつつ十分に冷却することができる。 Specifically, the outdoor control device 100 performs control to increase the valve opening degree of the electric expansion valve 29 when the discharge temperature of the compressor 20 exceeds a preset temperature, and the discharge temperature of the compressor 20 Is less than or equal to a preset value, and when the degree of superheat of the suction gas of the compressor 20 exceeds a preset value, control is performed to increase the valve opening degree of the electric expansion valve 29 and compression is performed. When the discharge temperature of the compressor 20 is not more than a predetermined value and the superheat degree of the suction gas of the compressor 20 is not more than a preset value, the valve opening degree of the electric expansion valve 29 is decreased. Take control. Thereby, the compressor 20 can be sufficiently cooled while preventing liquid compression.

なお、上述した実施の形態は、本発明の一実施態様を示すものであり、本発明の範囲内で任意に変形及び応用可能であることは勿論である。例えば、上述した実施の形態では、空気調和装置１が２台の室内ユニットと２台の室外ユニットとを備える構成としたが、本発明はこれに限定されず、室外ユニットの数および室内ユニットの数は任意であり、その他の細部構成についても任意に変更可能である。 The embodiment described above shows one embodiment of the present invention, and it is needless to say that the embodiment can be arbitrarily modified and applied within the scope of the present invention. For example, in the above-described embodiment, the air conditioner 1 is configured to include two indoor units and two outdoor units. However, the present invention is not limited to this, and the number of outdoor units and the number of indoor units are The number is arbitrary, and other details can be arbitrarily changed.

本発明の実施の形態にかかる空気調和装置の冷媒回路図である。It is a refrigerant circuit figure of the air harmony device concerning an embodiment of the invention. 図１に示す室外ユニットの冷媒回路図である。It is a refrigerant circuit figure of the outdoor unit shown in FIG. 室外制御装置による補助冷却回路の電動膨張弁の弁開度制御に係る動作を示すフローチャートである。It is a flowchart which shows the operation | movement which concerns on the valve opening degree control of the electric expansion valve of the auxiliary | assistant cooling circuit by an outdoor control apparatus.

Explanation of symbols

１空気調和装置（冷凍装置）
２Ａ、２Ｂ室外ユニット
３Ａ、３Ｂ室内ユニット
５冷媒配管
１０室内熱交換器（利用側熱交換器）
２０Ａ、２０Ｂ１、２０Ｂ２圧縮機
２１室外熱交換器（熱源側熱交換器）
２２膨張弁
２３レシーバタンク
２４アキュムレータ
２５オイルセパレータ
２６膨張弁（減圧装置）
２８補助冷却回路（過冷却熱交換器）
２９電動膨張弁（別の膨張弁）
３０冷媒吸込管
３１冷媒吐出管
３１Ａ、３１Ｂ、３１Ｃ冷媒吐出分岐管
３２暖房経路用配管
３３配管（第１冷媒通路）
３４分岐管（第２冷媒通路）
３５冷媒配管（第２冷媒通路）
１００室外制御装置（制御手段）
ＳＡ１圧力センサ
ＳＰ１、ＳＰ２、ＳＰ３、ＳＰ４温度センサ 1 Air conditioning equipment (refrigeration equipment)
2A, 2B Outdoor unit 3A, 3B Indoor unit 5 Refrigerant piping 10 Indoor heat exchanger (use side heat exchanger)
20A, 20B1, 20B2 Compressor 21 Outdoor heat exchanger (heat source side heat exchanger)
22 expansion valve 23 receiver tank 24 accumulator 25 oil separator 26 expansion valve (pressure reduction device)
28 Auxiliary cooling circuit (supercooling heat exchanger)
29 Electric expansion valve (another expansion valve)
30 Refrigerant suction pipe 31 Refrigerant discharge pipe 31A, 31B, 31C Refrigerant discharge branch pipe 32 Heating path pipe 33 Pipe (first refrigerant path)
34 Branch pipe (second refrigerant passage)
35 Refrigerant piping (second refrigerant passage)
100 Outdoor control device (control means)
SA1 Pressure sensor SP1, SP2, SP3, SP4 Temperature sensor

Claims

In a refrigeration apparatus comprising a compressor, a heat source side heat exchanger, a decompression device and a use side heat exchanger,
A first refrigerant passage that guides the refrigerant that has passed through the pressure reducing device to the user side heat exchanger as it is between the pressure reducing device and the use side heat exchanger, and a refrigerant that has passed through the pressure reducing device and another expansion valve. And a second refrigerant passage that leads to a suction pipe of the compressor, and includes a supercooling heat exchanger that causes heat exchange between the refrigerant flowing through each refrigerant passage and supercools the refrigerant flowing through the first refrigerant passage,
Control the valve opening of the other expansion valve according to the suction gas superheat degree of the compressor, and when the discharge temperature of the compressor reaches a preset set value, the suction of the compressor Regardless of the degree of gas superheating, provided with a control means for increasing the valve opening of the other expansion valve,
A refrigeration apparatus characterized by.

The refrigeration apparatus according to claim 1, wherein the control means gradually increases the valve opening degree of the expansion valve in accordance with an increase in discharge temperature of the compressor.

The refrigeration apparatus according to claim 1 or 2, wherein the control means gradually increases the valve opening degree of the expansion valve in accordance with an increase in the degree of superheat of the suction gas of the compressor.

The control means includes
When the discharge temperature of the compressor exceeds a preset temperature, control to increase the valve opening of the expansion valve,
When the discharge temperature of the compressor is equal to or lower than a preset temperature and the suction gas superheat degree of the compressor exceeds the preset superheat degree, the valve opening degree of the expansion valve is increased. Control
When the discharge temperature of the compressor is equal to or lower than a predetermined temperature and the suction gas superheat degree of the compressor is equal to or lower than a preset superheat degree, the valve opening degree of the expansion valve is decreased. Doing control,
The refrigeration apparatus according to claim 1.