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JP5296658B2 - Refrigerant circuit - Google Patents

Refrigerant circuit Download PDF

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JP5296658B2
JP5296658B2 JP2009251050A JP2009251050A JP5296658B2 JP 5296658 B2 JP5296658 B2 JP 5296658B2 JP 2009251050 A JP2009251050 A JP 2009251050A JP 2009251050 A JP2009251050 A JP 2009251050A JP 5296658 B2 JP5296658 B2 JP 5296658B2
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refrigerant
compressor
discharge
temperature
path
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JP2011094921A (en
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啓二 杉森
良和 大田
恭子 野村
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Yanmar Co Ltd
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Yanmar Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerant circuit having a configuration in which a plurality of compressors are provided in parallel in the common refrigerant circuit and capable of sensing a backflow of a discharged refrigerant in the state where the compressor during operation and the compressor during stop are mixed. <P>SOLUTION: The refrigerant circuit 1 includes a control device 10 detecting a sensed pressure PH of a discharge route 12, a sensed pressure PL of a suction route 11, sensed temperatures TD1, TD2 on discharge sides of the respective compressors 21, 22 and a sensed temperature TS in the suction route 11, calculating a theoretical refrigerant discharge temperature TDt based on compressor efficiency, determining whether the sensed temperature TD1 on the discharge side of the compressor 21 during operation is abnormally higher than the theoretical refrigerant discharge temperature TDt, outputting instruction to stop all of the compressors 21, 22 during operation when it is determined that the sensed temperature TD1 is abnormally higher than the theoretical refrigerant discharge temperature TDt, determining whether the sensed pressures PL, PH of the discharge route 12 and the suction route 11 reach a pressure equalization state for a predetermined time without opening a bypass valve 23 after the stop instruction, and determining that a refrigerant backflow occurs when it is determined that the sensed pressures PL, PH reach the pressure equalization state. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

本発明は、1台または2台以上の圧縮機を駆動するように構成された冷媒回路に関するものである。   The present invention relates to a refrigerant circuit configured to drive one or more compressors.

従来より、2台の圧縮機を共通の冷媒経路に並列に設けた冷媒回路が開示されている(特許文献1参照)。   Conventionally, a refrigerant circuit in which two compressors are provided in parallel in a common refrigerant path has been disclosed (see Patent Document 1).

上記従来の冷媒回路は、空調容量に対応して、何れか1台または2台の圧縮機を駆動するようになされていた。   The conventional refrigerant circuit is configured to drive any one or two compressors corresponding to the air conditioning capacity.

特開2000−304373号公報JP 2000-304373 A

しかし、上記従来の冷媒回路の場合、次のような不都合を生じることとなる。   However, in the case of the conventional refrigerant circuit, the following inconvenience occurs.

すなわち、何れか1台の圧縮機を駆動し、他方を停止する運転状態において、停止中の圧縮機内部の気密性能が劣化していると、運転中の圧縮機からの吐出冷媒が停止中の圧縮機の吐出口から吸入口に逆流する短絡現象が発生する。このような吐出冷媒の短絡状態が発生すれば、運転中の圧縮機の吐出温度が急激に上昇し、許容上限温度に達するため、空調運転を継続できない等の不具合が発生する。   That is, when the airtight performance inside the stopped compressor is deteriorated in the operation state in which any one compressor is driven and the other is stopped, the refrigerant discharged from the operating compressor is stopped. A short-circuit phenomenon occurs that flows backward from the discharge port of the compressor to the suction port. If such a short circuit state of the discharged refrigerant occurs, the discharge temperature of the compressor during operation suddenly rises and reaches the allowable upper limit temperature, which causes problems such as the inability to continue the air conditioning operation.

本発明は係る実情に鑑みてなされたものであって、複数の圧縮機を共通の冷媒回路に並列に設ける構成であって、運転中と停止中の圧縮機が混在する状態において、吐出冷媒の逆流による停止側圧縮機の逆転を検知することができる冷媒回路を提供することを目的としている。   The present invention has been made in view of such circumstances, and is configured to provide a plurality of compressors in parallel in a common refrigerant circuit, and in a state where compressors that are operating and stopped are mixed, It aims at providing the refrigerant circuit which can detect reverse rotation of the stop side compressor by backflow.

上記課題を解決するための本発明の冷媒回路は、複数の圧縮機を共通の吸入経路および吐出経路に対して並列に設け、各圧縮機の吐出側に温度センサを設け、共通の吸入経路に温度センサを設け、共通の吸入経路および吐出経路のそれぞれに圧力センサを設け、通常時閉のバイパス弁を備えた共通の吐出経路と吸入経路の接続経路を設け、計時手段を設けた冷媒回路であって、運転中と停止中の圧縮機が混在する運転状態において、共通の吐出経路の検知圧力と、共通の吸入経路の検知圧力と、検知温度および圧縮機効率に基づき理論冷媒吐出温度を算出し、運転中の圧縮機の吐出側の検知温度が理論冷媒吐出温度よりも異常に高温であるか否かを判定し、異常に高温であると判定した場合に運転中の全ての圧縮機を停止する指令を出力し、停止指令の出力後でバイパス弁を開くことなく所定時間の間に共通の吐出経路と吸入経路の検知圧力が均圧状態に達するか否かを判定し、停止指令の出力後でバイパス弁を開くまでに均圧状態に達したと判定した場合に冷媒逆流が発生していると判定する、演算出段を有するものである。   In the refrigerant circuit of the present invention for solving the above problems, a plurality of compressors are provided in parallel to a common suction path and a discharge path, a temperature sensor is provided on the discharge side of each compressor, and a common suction path is provided. A refrigerant circuit having a temperature sensor, a pressure sensor in each of the common suction path and the discharge path, a common discharge path having a normally closed bypass valve, a connection path for the suction path, and a timing means Therefore, in an operating state where both operating and stopped compressors are mixed, the theoretical refrigerant discharge temperature is calculated based on the detection pressure of the common discharge path, the detection pressure of the common suction path, the detection temperature, and the compressor efficiency. If the detected temperature on the discharge side of the operating compressor is abnormally higher than the theoretical refrigerant discharge temperature, and if it is determined that the detected temperature is abnormally high, all the operating compressors are Output a command to stop, After the stop command is output, it is determined whether or not the detected pressure in the common discharge path and suction path reaches a pressure equalized state for a predetermined time without opening the bypass valve, and the bypass valve is opened after the stop command is output. When it is determined that the pressure equalization state has been reached by the time, it is determined that the refrigerant backflow has occurred.

また、上記冷媒回路において、圧縮機台数が2台であり、一方の圧縮機が運転中で、他方が停止中の運転状態で冷媒逆流が発生していると判定した場合に当該判定後は冷媒逆流判定時に停止中の圧縮機が運転中のときだけ冷媒逆流判定時に運転中だった圧縮機を運転するよう、設定する手段を有するものである。   In the refrigerant circuit, when it is determined that the number of compressors is two, one of the compressors is in operation, and the other is in a stopped operation state, a refrigerant reverse flow is generated. It has a means to set so that the compressor which was operating at the time of refrigerant backflow judgment is operated only when the compressor stopped at the time of backflow judgment is in operation.

以上述べたように、本発明の冷媒回路によると、複数の圧縮機を共通の冷媒回路に並列に設ける構成であって、運転中と停止中の圧縮機が混在する状態において、吐出冷媒の逆流による停止側圧縮機の逆転を検知することができる。   As described above, according to the refrigerant circuit of the present invention, a configuration in which a plurality of compressors are provided in parallel in a common refrigerant circuit, and in a state where compressors in operation and stopped are mixed, backflow of discharged refrigerant It is possible to detect the reverse rotation of the stop side compressor.

また、請求項2記載の冷媒回路によると、気密性が劣化している圧縮機が停止中にもう一方の圧縮機を運転することを防止して、吐出冷媒の逆流による停止側圧縮機の逆転を防止できる。   Further, according to the refrigerant circuit of claim 2, it is possible to prevent the compressor having deteriorated airtightness from operating the other compressor while it is stopped, and to reverse the stop side compressor due to the reverse flow of the discharged refrigerant. Can be prevented.

本発明に係る冷媒回路の冷房時の冷媒の流れを示す回路図である。It is a circuit diagram which shows the flow of the refrigerant | coolant at the time of cooling of the refrigerant circuit which concerns on this invention. 本発明に係る冷媒回路の暖房時の冷媒の流れを示す回路図である。It is a circuit diagram which shows the flow of the refrigerant | coolant at the time of the heating of the refrigerant circuit which concerns on this invention. 本発明に係る冷媒回路の圧縮機部分の要部構成の概略を示す回路図である。It is a circuit diagram which shows the outline of the principal part structure of the compressor part of the refrigerant circuit which concerns on this invention. 本発明に係る冷媒回路の制御装置のブロック図である。It is a block diagram of the control apparatus of the refrigerant circuit which concerns on this invention. 本発明に係る冷媒回路の制御装置のフローチャートである。It is a flowchart of the control apparatus of the refrigerant circuit which concerns on this invention. 本発明に係る冷媒回路において、エンジンによる圧縮機の駆動を説明する概略図である。It is the schematic explaining the drive of the compressor by an engine in the refrigerant circuit which concerns on this invention. 本発明に係る冷媒回路において通常運転時と逆流時とにおる圧縮機の吐出温度の違いを説明するグラフである。It is a graph explaining the difference of the discharge temperature of the compressor at the time of normal operation and the time of a reverse flow in the refrigerant circuit which concerns on this invention. 本発明に係る冷媒回路において通常運転時と逆流時とにおける吐出経路の圧力と吸入経路の圧力との関係を示すグラフである。6 is a graph showing the relationship between the pressure in the discharge path and the pressure in the suction path during normal operation and reverse flow in the refrigerant circuit according to the present invention.

以下、本発明の実施の形態を図面を参照して説明する。   Hereinafter, embodiments of the present invention will be described with reference to the drawings.

図1および図2は冷媒回路1の冷暖房時の冷媒の流れを示し、図3は同冷媒回路1の圧縮機21,22の部分の概略を示し、図4は同冷媒回路1において、冷媒が、圧縮機21,22の吐出側経路21b,22bから吸入側経路21a,22aに逆流しているか否かを検知する制御装置10のブロック図を示し、図5は同制御装置10による制御フロー図を示している。   1 and 2 show the flow of refrigerant during cooling and heating of the refrigerant circuit 1, FIG. 3 shows an outline of the compressors 21 and 22 of the refrigerant circuit 1, and FIG. FIG. 5 is a block diagram of the control device 10 that detects whether or not the discharge-side passages 21b and 22b of the compressors 21 and 22 are flowing back to the suction-side passages 21a and 22a, and FIG. Is shown.

この冷媒回路1は、2台の圧縮機21,22を共通の吸入経路11および吐出経路12に対して並列に設け、各圧縮機21,22の吐出側経路21b,22bに温度センサ31,32を設け、共通の吸入経路11に温度センサ33を設け、共通の吸入経路11および吐出経路12のそれぞれに圧力センサ41,42を設け、通常時閉のバイパス弁23を備えた共通の吐出経路12と吸入経路11の接続経路13を設けて構成されている。   In the refrigerant circuit 1, two compressors 21 and 22 are provided in parallel to the common suction path 11 and the discharge path 12, and temperature sensors 31 and 32 are provided in the discharge-side paths 21b and 22b of the compressors 21 and 22, respectively. , A temperature sensor 33 is provided in the common suction path 11, pressure sensors 41 and 42 are provided in each of the common suction path 11 and the discharge path 12, and the common discharge path 12 having the normally closed bypass valve 23 is provided. And a connection path 13 of the suction path 11 is provided.

各圧縮機21,22の吐出側経路21b,22bに設けた温度センサ31,32は、圧縮機21,22から吐出される冷媒の温度を測定することができる位置であれば、吐出側経路21b,22bの何処に設けたものであってもよい。   If the temperature sensors 31 and 32 provided in the discharge side paths 21b and 22b of the compressors 21 and 22 are positions where the temperature of the refrigerant discharged from the compressors 21 and 22 can be measured, the discharge side path 21b. , 22b may be provided anywhere.

共通の吸入経路11に設けた温度センサ33は、圧縮機21,22に吸入される冷媒の温度を測定することができる位置であれば、共通の吸入経路11の何処に設けたものであってもよい。図1および図2では、共通の吸入経路11に設けられたキャピラリチューブ11aよりも上流側に設けられている。この場合、キャピラリチューブ11aによる冷媒のガス化が促進される手前の位置なので、冷媒の温度は不安定にならず、測定位置としては好ましい。   The temperature sensor 33 provided in the common suction path 11 is provided anywhere in the common suction path 11 as long as the temperature of the refrigerant sucked into the compressors 21 and 22 can be measured. Also good. In FIG. 1 and FIG. 2, it is provided upstream of the capillary tube 11 a provided in the common suction path 11. In this case, since the position before the gasification of the refrigerant by the capillary tube 11a is promoted, the temperature of the refrigerant does not become unstable and is preferable as a measurement position.

共通の吸入経路11に設けた圧力センサ41は、圧縮機21,22に吸入される冷媒の圧力を測定することができる位置であれば、吸入経路11の何処に設けたものであってもよい。図1および図2では、共通の吸入経路11に設けられたキャピラリチューブ11aよりも上流側に設けられている。この場合、キャピラリチューブ11aによる冷媒のガス化が促進される手前の位置なので、冷媒の圧力は不安定にならず、測定位置としては好ましい。   The pressure sensor 41 provided in the common suction path 11 may be provided anywhere in the suction path 11 as long as the pressure of the refrigerant sucked into the compressors 21 and 22 can be measured. . In FIG. 1 and FIG. 2, it is provided upstream of the capillary tube 11 a provided in the common suction path 11. In this case, since the position before the gasification of the refrigerant by the capillary tube 11a is promoted, the pressure of the refrigerant does not become unstable and is preferable as a measurement position.

共通の吐出経路12に設けた圧力センサ42は、圧縮機21,22から吐出される冷媒の圧力を測定することができる位置であれば、吐出経路12の何処に設けたものであってもよい。図1および図2では、オイルセパレータ24の圧力が加わっている接続経路13で測定している。この場合、オイルセパレータ24の容量があるので、圧縮機21,22からの冷媒の圧力は不安定にならず、測定位置としては好ましい。   The pressure sensor 42 provided in the common discharge path 12 may be provided anywhere in the discharge path 12 as long as the pressure of the refrigerant discharged from the compressors 21 and 22 can be measured. . In FIG. 1 and FIG. 2, the measurement is performed in the connection path 13 to which the pressure of the oil separator 24 is applied. In this case, since the capacity of the oil separator 24 is sufficient, the pressure of the refrigerant from the compressors 21 and 22 does not become unstable, which is preferable as a measurement position.

まず、冷媒回路1のヒートポンプサイクルについて説明する。   First, the heat pump cycle of the refrigerant circuit 1 will be described.

図1に示すように、冷房運転時、圧縮機21,22で圧縮された冷媒ガスは、オイルセパレータ24でオイルから分離された後、四方弁25を介して室外熱交換器26a,26bへと流入する。その後、室外熱交換器26a,26bからブリッジ回路27を経た冷媒は、リキッドレシーバ28で液冷媒として貯留される。この液冷媒は、再度ブリッジ回路27を経て閉鎖弁BV1から室内機5の電子膨張弁51を経て室内熱交換器52で蒸発気化した後、閉鎖弁BV2から圧縮機21,22へと吸引される。この際の冷房は、電子膨張弁51の開度調整を行うことによって制御される。また、冷房能力が不足する場合、冷媒は、リキッドレシーバ28からブリッジ回路27へと向かう冷媒の一部が、電子膨張弁EV1を開度調整して過冷却器28aへと導かれる。これによってリキッドレシーバ28内の液冷媒は、過冷却され冷房能力の不足を解消するように制御される。過冷却器28aを通過した冷媒は、通常の冷媒経路を通過するガス冷媒と合流する。   As shown in FIG. 1, during cooling operation, the refrigerant gas compressed by the compressors 21 and 22 is separated from the oil by the oil separator 24, and then to the outdoor heat exchangers 26 a and 26 b through the four-way valve 25. Inflow. Thereafter, the refrigerant that has passed through the bridge circuit 27 from the outdoor heat exchangers 26 a and 26 b is stored as liquid refrigerant in the liquid receiver 28. The liquid refrigerant passes through the bridge circuit 27 again, evaporates and evaporates in the indoor heat exchanger 52 through the electronic expansion valve 51 of the indoor unit 5 from the closing valve BV1, and then is sucked into the compressors 21 and 22 from the closing valve BV2. . The cooling at this time is controlled by adjusting the opening degree of the electronic expansion valve 51. When the cooling capacity is insufficient, a part of the refrigerant from the liquid receiver 28 to the bridge circuit 27 is led to the supercooler 28a by adjusting the opening of the electronic expansion valve EV1. As a result, the liquid refrigerant in the liquid receiver 28 is supercooled and controlled so as to eliminate the lack of cooling capacity. The refrigerant that has passed through the subcooler 28a merges with the gas refrigerant that passes through the normal refrigerant path.

図2に示すように、暖房運転時、圧縮機21,22で圧縮された冷媒ガスは、オイルセパレータ24でオイルから分離された後、四方弁25を介して閉鎖弁BV2から室内機5へ供給され、室内熱交換器52で凝縮液化した後、電子膨張弁51を経て室外機2へと導かれる。   As shown in FIG. 2, during heating operation, the refrigerant gas compressed by the compressors 21 and 22 is separated from the oil by the oil separator 24 and then supplied from the closing valve BV2 to the indoor unit 5 via the four-way valve 25. After being condensed and liquefied by the indoor heat exchanger 52, it is led to the outdoor unit 2 through the electronic expansion valve 51.

室外機2へと導かれた液冷媒は、閉鎖弁BV1からブリッジ回路27を経てリキッドレシーバ28へと回収される。この液冷媒は、再度ブリッジ回路27の電子膨張弁EV2で開度調整して室外熱交換器26a,26bへと導かれる。この室外熱交換器26a,26bで蒸発気化した冷媒は、四方弁25から再度圧縮機21,22へと吸引される。また、暖房運転では、室外熱交換器26a,26bの蒸発能力の不足を補うため、冷媒の一部が電子膨張弁EV3から廃熱回収器29へ導かれる。この廃熱回収器29を通過する冷媒は、圧縮機21,22の駆動源であるエンジン20(図6参照)の廃熱によって蒸発気化し、通常の冷媒経路を通過するガス冷媒と合流する。   The liquid refrigerant guided to the outdoor unit 2 is collected from the closing valve BV1 to the liquid receiver 28 via the bridge circuit 27. The liquid refrigerant is led to the outdoor heat exchangers 26a and 26b after the opening degree is adjusted again by the electronic expansion valve EV2 of the bridge circuit 27. The refrigerant evaporated by the outdoor heat exchangers 26a and 26b is sucked again from the four-way valve 25 to the compressors 21 and 22. In the heating operation, part of the refrigerant is led from the electronic expansion valve EV3 to the waste heat recovery device 29 in order to compensate for the shortage of the evaporation capability of the outdoor heat exchangers 26a and 26b. The refrigerant that passes through the waste heat recovery device 29 is evaporated by the waste heat of the engine 20 (see FIG. 6) that is the drive source of the compressors 21 and 22, and merges with the gas refrigerant that passes through the normal refrigerant path.

上記した冷房運転時または暖房運転時において、冷媒回路1は、通常時はバイパス弁23が閉じた状態となされているが、圧縮機21,22の吸入経路11に吸引される冷媒の湿り度が大きくなると、液ハンマによる圧縮機21,22の破損を防止するために、バイパス弁23が開かれる。   During the cooling operation or the heating operation described above, the refrigerant circuit 1 is normally in a state where the bypass valve 23 is closed, but the wetness of the refrigerant sucked into the suction passages 11 of the compressors 21 and 22 is high. When it becomes larger, the bypass valve 23 is opened to prevent the compressors 21 and 22 from being damaged by the liquid hammer.

なお、図1において、冷媒回路1は、室内機3が1台しか接続されていないが、閉鎖弁BV1と閉鎖弁BV2との間に複数台の室内機5が接続可能となされている。また、圧縮機21,22は、これら接続された室内機5の運転状況に応じて何れか1台または2台が運転される。これら圧縮機21,22の運転切り替えは、図6に示すように、駆動源のエンジン20に2台の圧縮機21,22が、ベルトやチェーンなどの駆動連結手段20aによって駆動連結されており、クラッチ(図示省略)のオンオフで何れか1台または2台同時の駆動が可能となるように構成されている。   In FIG. 1, only one indoor unit 3 is connected to the refrigerant circuit 1, but a plurality of indoor units 5 can be connected between the closing valve BV1 and the closing valve BV2. Further, one or two of the compressors 21 and 22 are operated according to the operation status of the connected indoor units 5. As shown in FIG. 6, the operation switching of these compressors 21 and 22 is such that two compressors 21 and 22 are drivingly connected to a driving source engine 20 by driving connecting means 20a such as a belt or a chain, One or two of them can be driven simultaneously by turning on and off a clutch (not shown).

上記構成において、本発明の冷媒回路1の制御装置10は、例えば圧縮機21が運転し、圧縮機22が停止している状態において、圧縮機22の吐出側経路22bから吸入側経路22aへの冷媒の逆流発生を判定することができるようになされている。   In the above configuration, the control device 10 of the refrigerant circuit 1 according to the present invention, for example, when the compressor 21 is operating and the compressor 22 is stopped, is connected from the discharge side path 22b of the compressor 22 to the suction side path 22a. The generation of the reverse flow of the refrigerant can be determined.

図4は冷媒の逆流を判定する制御装置10のブロック図を示し、図5は同判定を行う際の制御フローを示している。以下において、説明の便宜上、圧縮機21が運転し、圧縮機22が停止している状態を仮定する。   FIG. 4 shows a block diagram of the control device 10 for determining the reverse flow of the refrigerant, and FIG. 5 shows a control flow when the same determination is performed. In the following, for convenience of explanation, it is assumed that the compressor 21 is operating and the compressor 22 is stopped.

この制御装置10には、圧縮機21,22の吐出側経路21b,22bに設けた温度センサ31,32からの検知温度TD1,TD2と、共通の吐出経路12に設けた圧力センサ42からの検知圧力PHと、共通の吸入経路11に設けた圧力センサ41からの検知圧力PLと、共通の吸入経路11に設けた温度センサ33からの検知温度TSとが入力され、これらの入力情報に基づいて圧縮機21,22を駆動するエンジン20の停止または始動の指令を出したり、圧縮機21,22の補修指令を出したりするように構成されている。   The control device 10 includes detection temperatures TD1 and TD2 from temperature sensors 31 and 32 provided in the discharge-side paths 21b and 22b of the compressors 21 and 22 and detection from a pressure sensor 42 provided in the common discharge path 12. The pressure PH, the detected pressure PL from the pressure sensor 41 provided in the common suction path 11, and the detected temperature TS from the temperature sensor 33 provided in the common suction path 11 are input, and based on these input information The engine 20 that drives the compressors 21 and 22 is configured to issue a stop or start command, or to issue a repair command for the compressors 21 and 22.

制御装置10では、まず、実際の冷媒吐出温度TD1が、理論上の冷媒吐出温度TDtよりも異常に高温であるか否かを判定する。その方法としては、図7に示すように、入力情報に基づいて圧縮機21の理論上の冷媒吐出温度TDtを算出する。制御装置10では、この算出された理論上の冷媒吐出温度TDtに圧縮機21の最低運転効率を考慮して冷媒吐出温度TDrに換算し、実際の冷媒吐出温度TD1が、理論上の冷媒吐出温度TDtから換算した最低運転効率の冷媒吐出温度TDrまでの範囲内に有るか否かを判定する(ステップ1)。   In the control device 10, first, it is determined whether or not the actual refrigerant discharge temperature TD1 is abnormally higher than the theoretical refrigerant discharge temperature TDt. As the method, as shown in FIG. 7, the theoretical refrigerant discharge temperature TDt of the compressor 21 is calculated based on the input information. In the control device 10, the calculated theoretical refrigerant discharge temperature TDt is converted into the refrigerant discharge temperature TDr in consideration of the minimum operation efficiency of the compressor 21, and the actual refrigerant discharge temperature TD1 is converted into the theoretical refrigerant discharge temperature. It is determined whether or not it is within the range from the TDt to the refrigerant discharge temperature TDr with the lowest operating efficiency (step 1).

実際の冷媒吐出温度TD1が、この範囲内にある場合、制御装置10は、逆流していない通常運転時と判断し、あらかじめ設定した時間毎に上記した判定を繰り返す。実際の冷媒吐出温度TD1が、この範囲よりも高温である場合、逆流による停止側圧縮機22の逆転時と仮判断し、制御装置10は、運転中の圧縮機21を駆動するエンシン20の停止指令を出力する(ステップ2)。   When the actual refrigerant discharge temperature TD1 is within this range, the control device 10 determines that the normal operation is not in reverse flow, and repeats the above determination every preset time. When the actual refrigerant discharge temperature TD1 is higher than this range, it is temporarily determined that the stop-side compressor 22 is reversely rotated due to the backflow, and the control device 10 stops the engine 1 that drives the compressor 21 during operation. A command is output (step 2).

なお、上記では、実際の冷媒吐出温度TD1が、理論上の冷媒吐出温度TDtから換算した冷媒吐出温度TDrまでの範囲内に有るか否か、その温度差によって判定しているが、実際の冷媒吐出温度TD1と、理論上の冷媒吐出温度TDtとを比較した比率によって判定してもよい。すなわち、理論上の冷媒吐出温度TDtの場合の圧縮機21の運転効率を100とし、この理論上の冷媒吐出温度TDtと、実際の冷媒吐出温度TD1との比率から、実際の冷媒吐出温度TD1の場合の圧縮機21の運転効率を求める。この実際の冷媒吐出温度TD1における圧縮機21の運転効率が、あらかじめ設定した運転効率、例えば、100〜75%に有るか否かを判定する(ステップ1)。制御装置10は、この範囲内の比率に納まっている場合、通常運転時と判断し、あらかじめ設定した時間毎に上記の判定を繰り返す。範囲内の比率から外れていれば、逆流による停止側圧縮機22の逆転時と仮判断し、制御装置10は、運転中の圧縮機21を駆動するエンジン20の停止指令を出力する(ステップ2)。   In the above description, whether or not the actual refrigerant discharge temperature TD1 is within the range from the theoretical refrigerant discharge temperature TDt to the converted refrigerant discharge temperature TDr is determined based on the temperature difference. You may determine by the ratio which compared discharge temperature TD1 and theoretical refrigerant | coolant discharge temperature TDt. That is, the operation efficiency of the compressor 21 in the case of the theoretical refrigerant discharge temperature TDt is set to 100, and the actual refrigerant discharge temperature TD1 is calculated from the ratio of the theoretical refrigerant discharge temperature TDt and the actual refrigerant discharge temperature TD1. In this case, the operation efficiency of the compressor 21 is obtained. It is determined whether or not the operation efficiency of the compressor 21 at the actual refrigerant discharge temperature TD1 is within a preset operation efficiency, for example, 100 to 75% (step 1). When the control device 10 falls within the ratio within this range, the control device 10 determines that the operation is normal, and repeats the above determination every preset time. If the ratio is out of the range, it is temporarily determined that the stop-side compressor 22 is reversely rotated due to the backflow, and the control device 10 outputs a stop command for the engine 20 that drives the compressor 21 in operation (step 2). ).

次に、制御装置10では、エンジン20の停止指令を出してから後、バイパス弁23を開くことなく、共通の吐出経路12の検知圧力PHと、共通の吸入経路11の検知圧力PLとをモニターし、所定の時間内に均等の圧力になるか否かを判定する(ステップ3)。図8に示すように、エンジン20を停止しても、正常の場合は、バイパス弁23を開くまでの間は、吐出経路12の検知圧力PHと、吸入経路11の検知圧力PLとは、その圧力が保たれている。しかし、逆流による停止側圧縮機22の逆転を生じている場合は、エンジン20を停止すると、吐出経路12の検知圧力PHと、吸入経路11の検知圧力PLとは、バイパス弁23を開かずとも所定の時間内に均等の圧力になる。   Next, the control device 10 monitors the detected pressure PH of the common discharge path 12 and the detected pressure PL of the common suction path 11 without opening the bypass valve 23 after issuing a stop command for the engine 20. Then, it is determined whether or not the pressure becomes equal within a predetermined time (step 3). As shown in FIG. 8, even if the engine 20 is stopped, in the normal case, until the bypass valve 23 is opened, the detected pressure PH of the discharge path 12 and the detected pressure PL of the suction path 11 are Pressure is maintained. However, when reverse rotation of the stop-side compressor 22 is caused by backflow, when the engine 20 is stopped, the detection pressure PH in the discharge path 12 and the detection pressure PL in the suction path 11 do not open the bypass valve 23. The pressure becomes equal within a predetermined time.

したがって、バイパス弁23を開かない状態で所定の時間内に均等の圧力にならなかった場合は、通常運転時と判断し、エンジン20が再始動されて通常運転に戻り(ステップ4)、以後、ステップ1からの判定が繰り返される。   Therefore, when the pressure is not equalized within a predetermined time without opening the bypass valve 23, it is determined that the engine is in normal operation, the engine 20 is restarted and returns to normal operation (step 4). The determination from step 1 is repeated.

バイパス弁23を開かない状態で所定の時間内に均等の圧力になった場合は、停止している圧縮機22で吐出側経路22bから吸入側経路22aへの冷媒の逆流による停止側だった圧縮機22の逆転が発生しているものとして検知され(ステップ5)、圧縮機22の補修指令が出される(ステップ6)。この補修指令は、逆流を意味するエラー信号を制御機器画面に表示したり、エラーを知らせるランプの点灯、ブザー音の発生などによって行われる。   When the pressure is equalized within a predetermined time without opening the bypass valve 23, the compressor 22 that has been stopped is the compressor that has been stopped due to the reverse flow of the refrigerant from the discharge side passage 22b to the suction side passage 22a. It is detected that reverse rotation of the machine 22 has occurred (step 5), and a repair command for the compressor 22 is issued (step 6). This repair command is issued by displaying an error signal indicating backflow on the control device screen, turning on a lamp notifying an error, or generating a buzzer sound.

なお、吐出経路12の検知圧力PHと、吸入経路11の検知圧力PLとが、所定の時間内に均等の圧力になるか否かについては、吐出経路12の検知圧力PHと、吸入経路11の検知圧力PLとの差圧をモニターし、この差圧が、あらかじめ設定した圧力差以下になった場合に均等の圧力になると判断するものであってもよいし、吐出経路12の検知圧力PHと、吸入経路11の検知圧力PLとの比率をモニターし、この比率が、あらかじめ設定した比率の範囲内から外れた場合に均等の圧力になると判断するものであってもよい。   Whether or not the detected pressure PH of the discharge path 12 and the detected pressure PL of the suction path 11 become equal pressures within a predetermined period of time depends on the detected pressure PH of the discharge path 12 and the suction path 11. The differential pressure with respect to the detection pressure PL may be monitored, and when this differential pressure becomes equal to or less than a preset pressure difference, it may be determined that the pressure becomes equal, or the detection pressure PH of the discharge path 12 The ratio with the detected pressure PL of the suction path 11 may be monitored, and it may be determined that the pressure becomes equal when the ratio is out of the preset ratio range.

この制御装置10を備えた冷媒回路1によると、停止中の圧縮機22において、吐出側経路22bから吸入側経路22aへの冷媒の逆流による停止側圧縮機22の逆転が発生しているか否かを検知することができる。   According to the refrigerant circuit 1 provided with the control device 10, in the stopped compressor 22, whether or not the stop-side compressor 22 is reversed due to the reverse flow of the refrigerant from the discharge side passage 22b to the suction side passage 22a. Can be detected.

なお、停止中の圧縮機22が逆流による逆転を生じた場合であっても、運転中だった圧縮機21までもが逆流による逆転を生じるわけではない。したがって、停止中の圧縮機22が逆流による逆転を生じた場合は、この逆流による逆転を生じる圧縮機22を常に他方の圧縮機21に優先して運転させるように指令するプログラムを制御装置10に追加してもよい。これによって、気密性が劣化している圧縮機22が停止中にもう一方の圧縮機21を運転することを防止して、吐出冷媒の逆流による停止側圧縮機21の逆転を防止できる。   In addition, even if the stopped compressor 22 causes reverse rotation due to backflow, the compressor 21 that has been operating does not cause reverse rotation due to backflow. Therefore, when the stopped compressor 22 is reversed due to the reverse flow, the control device 10 is instructed to always operate the compressor 22 causing the reverse rotation due to the reverse flow with priority over the other compressor 21. May be added. As a result, the compressor 22 whose airtightness has deteriorated can be prevented from operating the other compressor 21 while it is stopped, and the reverse rotation of the stop-side compressor 21 due to the backflow of the discharged refrigerant can be prevented.

なお、本実施の形態では、説明の便宜上、圧縮機21が運転し、圧縮機22が停止している状態を仮定しているが、圧縮機22が運転し、圧縮機21が停止している状態であってもよい。   In this embodiment, for convenience of explanation, it is assumed that the compressor 21 is operating and the compressor 22 is stopped. However, the compressor 22 is operating and the compressor 21 is stopped. It may be in a state.

また、本実施の形態では、圧縮機21,22は2台となされているが、3台以上の場合であってもよい。   In the present embodiment, two compressors 21 and 22 are provided, but three or more compressors may be used.

本発明に係る冷媒回路は、複数台の圧縮機を有する冷媒回路を用いた各種空調装置に使用される。   The refrigerant circuit according to the present invention is used in various air conditioners using a refrigerant circuit having a plurality of compressors.

1 冷媒回路
10 制御装置(演算手段)
11 共通の吸入経路
12 共通の吐出経路
13 接続経路
2 室外機
21 圧縮機
21a 吸入側経路
21b 吐出側経路
22 圧縮機
22a 吸入側経路
22b 吐出側経路
23 バイパス弁
31 温度センサ
32 温度センサ
33 温度センサ
41 圧力センサ
42 圧力センサ
TD1 吐出経路の検知温度
TD2 吐出経路の検知温度
TS 吸入経路の検知温度
PL 吸入経路の検知圧力
PH 吐出経路の検知圧力
1 Refrigerant circuit 10 Control device (calculation means)
DESCRIPTION OF SYMBOLS 11 Common suction path 12 Common discharge path 13 Connection path 2 Outdoor unit 21 Compressor 21a Suction side path 21b Discharge side path 22 Compressor 22a Suction side path 22b Discharge side path 23 Bypass valve 31 Temperature sensor 32 Temperature sensor 33 Temperature sensor 41 pressure sensor 42 pressure sensor TD1 discharge path detection temperature TD2 discharge path detection temperature TS suction path detection temperature PL suction path detection pressure PH discharge path detection pressure

Claims (2)

複数の圧縮機を共通の吸入経路および吐出経路に対して並列に設け、各圧縮機の吐出側に温度センサを設け、共通の吸入経路に温度センサを設け、共通の吸入経路および吐出経路のそれぞれに圧力センサを設け、通常時閉のバイパス弁を備えた共通の吐出経路と吸入経路の接続経路を設け、計時手段を設けた冷媒回路であって、
運転中と停止中の圧縮機が混在する運転状態において、
共通の吐出経路の検知圧力と、共通の吸入経路の検知圧力と、各圧縮機の吐出側の検知温度と、共通の吸入経路の検知温度とを検知し、
圧縮機効率に基づき理論冷媒吐出温度を算出し、
運転中の圧縮機の吐出側の検知温度が理論冷媒吐出温度よりも異常に高温であるか否かを判定し、
異常に高温であると判定した場合に運転中の全ての圧縮機を停止する指令を出力し、
停止指令の出力後でバイパス弁を開くことなく所定時間の間に共通の吐出経路と吸入経路の検知圧力が均圧状態に達するか否かを判定し、
停止指令の出力後でバイパス弁を開くまでに均圧状態に達したと判定した場合に冷媒逆流が発生していると判定する、演算出段を有することを特徴とする冷媒回路。
A plurality of compressors are provided in parallel to a common suction path and discharge path, a temperature sensor is provided on the discharge side of each compressor, a temperature sensor is provided in the common suction path, and each of the common suction path and discharge path is provided. A refrigerant circuit provided with a pressure sensor, a common discharge path provided with a normally closed bypass valve, a connection path of a suction path, and a timing means,
In an operating state where both operating and stopped compressors are mixed,
Detecting the detection pressure of the common discharge path, the detection pressure of the common suction path, the detection temperature of the discharge side of each compressor, and the detection temperature of the common suction path,
Calculate the theoretical refrigerant discharge temperature based on the compressor efficiency,
Determine whether the detected temperature on the discharge side of the compressor during operation is abnormally higher than the theoretical refrigerant discharge temperature,
When it is determined that the temperature is abnormally high, a command to stop all compressors in operation is output.
Determine whether the detected pressure of the common discharge path and suction path reaches a pressure equalized state for a predetermined time without opening the bypass valve after outputting the stop command,
A refrigerant circuit having a calculation output stage for determining that a refrigerant reverse flow has occurred when it is determined that a pressure equalization state has been reached before the bypass valve is opened after a stop command is output.
請求項1記載の冷媒回路において、
圧縮機台数が2台であり、
一方の圧縮機が運転中で、他方が停止中の運転状態で冷媒逆流が発生していると判定した場合に当該判定後は冷媒逆流判定時に停止中の圧縮機が運転中のときだけ冷媒逆流判定時に運転中だった圧縮機を運転するよう、設定する手段を有することを特徴とする冷媒回路。
The refrigerant circuit according to claim 1,
The number of compressors is 2,
When it is determined that refrigerant backflow is occurring while one compressor is operating and the other is stopped, after the determination, refrigerant backflow is only performed when the stopped compressor is operating at the time of refrigerant backflow determination. A refrigerant circuit comprising means for setting so as to operate a compressor that was operating at the time of determination.
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