JP3705251B2

JP3705251B2 - Refrigeration cycle equipment

Info

Publication number: JP3705251B2
Application number: JP2002209107A
Authority: JP
Inventors: 茂生 ▲高▼田
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2002-07-18
Filing date: 2002-07-18
Publication date: 2005-10-12
Anticipated expiration: 2020-03-30
Also published as: JP2003042582A

Description

【０００１】
【発明の属する技術分野】
本発明は、冷凍機や空調機に用いられる冷凍サイクル装置に係り、特に、圧縮機の保護と各室内機における適正な冷媒温度の確保に関するものである。
【０００２】
【従来の技術】
従来の冷凍サイクル装置は、一般的に、図９に示すような構成がとられている。図において、１は圧縮機、２は凝縮器、３は絞り装置、４は蒸発器であり、これらは環状配置に連通して主冷媒回路を形成している。そして、圧縮機１、凝縮器２等により熱源機Ａが構成され、絞り装置３、蒸発器４等により室内機Ｂが構成されている。５は冷媒配管であり、熱源機Ａと、１台ないし複数台の室内機Ｂとを連通している。
熱源機Ａには、上記のほかに、凝縮器熱交換量調整手段としてのファン６、ガスバイパス手段７、液バイパス手段８等のアクチュエータが配備されている。また、圧縮機吐出圧力検出手段９、圧縮機吸入圧力検出手段１０、圧縮機吐出温度検知手段１１等のセンサも配備されている。そして、制御手段１４Ａは、各センサの検出値がそれぞれの許容範囲を逸脱しないよう、各アクチュエータを個々に制御している。例えば、圧縮機吐出圧力検出手段９により検出された冷媒吐出圧力に基づいて凝縮器２へのファン６の風量が制御され、圧縮機吸入圧力検出手段１０により検出された冷媒吸入圧力に基づいてガスバイパス手段７が開閉制御され、圧縮機吐出温度検知手段１１により検出された冷媒吐出温度に基づいて液バイパス手段８が開閉制御されていた。また、室内機Ｂにおいては、熱源機Ａの冷媒吸入圧力に相当する圧力に基づいて蒸発器４の蒸発圧力が一意に決まる運転が行なわれている。従来の冷凍サイクル装置は、このように構成されており、圧縮機１の適正な運転範囲を保つ保護制御を行ないつつ、室内機Ｂが設置されている環境を冷凍したり空調したりするようになっていた。
【０００３】
【発明が解決しようとする課題】
従来の冷凍サイクル装置は上記のように構成されていたので、以下のような課題があった。
特に、熱源機Ａと、蒸発器４および絞り手段３とが個別に自律分散制御される上記の冷凍サイクル装置においては、蒸発能力の変化に伴って圧縮機１の運転状態が大幅に変化することがある。かかる場合には、冷凍能力の安定供給や圧縮機１の安全運転範囲の確保ができなくなったり、保護制御による圧縮機１のサーモ発停頻度の増加をまねいたり、あるいは、蒸発温度低下に起因したデフロスト運転頻度の増加による室内温度変化の増大をまねいたりすることがあった。
また、冷媒配管５での圧力損失等により、室内側熱交換器４で要求される凝縮能力または蒸発能力が不足することがあった。
あるいは、複数台の室内側熱交換器４で要求される凝縮温度または蒸発温度が異なる場合に、例えば最高の凝縮温度、最低の蒸発温度に設定したことによる暖め過ぎや冷え過ぎ、あるいは、それに伴うサーモ発停頻度の増大やデフロスト運転頻度の増大等による室内温度変化の増大をまねくことがあった。
また、インバータ等を用いた容量制御による複雑な冷凍能力制御ではなく、簡便な冷凍能力制御手段が求められていた。
【０００４】
【課題を解決するための手段】
この発明に係る冷凍サイクル装置は、圧縮機、室外熱交換器等を接続してなる熱源機と、絞り手段、室内側熱交換器等を接続して成る複数台の室内機とを冷媒配管で連通したものであり、前記室内側熱交換器のガス冷媒側の冷媒回路に、ガス冷媒を加圧する冷媒加圧手段を設けることで、圧縮機の吸入圧力に対応した冷媒飽和温度以下の蒸発温度を実現させ、前記複数台の室内機で要求される室内側熱交換器の蒸発温度が異なるようにしたものである。
【０００５】
また、この発明に係る冷凍サイクル装置は、圧縮機、室外熱交換器等を接続してなる熱源機と、絞り手段、室内側熱交換器等を接続して成る複数台の室内機とを冷媒配管で連通したものであり、前記室内側熱交換器のガス冷媒側の冷媒回路に、ガス冷媒を加圧する冷媒加圧手段を設けることで、圧縮機の吐出圧力に対応した冷媒飽和温度以上の凝縮温度を実現させ、前記複数台の室内機で要求される室内側熱交換器の凝縮温度が異なるようにしたものである。
【０００６】
また、冷媒加圧手段と並列に、前記冷媒加圧手段の未使用時に低圧損経路を形成する第１バイパス手段を設けたものである。
【０００７】
また、冷媒を加圧して単方向に流通させる冷媒加圧手段と第２四方弁とを、圧縮機の吐出側に設けられた第１四方弁と室内側熱交換器との間に配備し、前記冷媒加圧手段の吐出側を前記第２四方弁の高圧側入口に接続するとともに、前記冷媒加圧手段の吸入側を前記第２四方弁の低圧側出口に接続し、前記第２四方弁の流路切替えにより冷媒を双方向に切替えて流通させる構成としたものである。
【００１０】
【発明の実施の形態】
実施の形態１．
図１は実施の形態１に係る冷凍サイクル装置の冷媒回路を示す構成図である。図１において、１は圧縮機、２は室外側熱交換器（冷房時は凝縮器）、３は絞り装置、４は室内側熱交換器（冷房時は蒸発器）であり、これらは環状配置に連通して主冷媒回路を形成している。ここでは、圧縮機１、凝縮器２等より熱源機Ａが構成され、絞り装置３、蒸発器４等より室内機Ｂが構成される。５は冷媒配管であり、熱源機Ａと１台ないし複数台の室内機Ｂとを連通している。熱源機Ａには、上記のほかに、凝縮器熱交換量調整手段としてのファン６、圧縮機１の吐出側と吸入側間の冷媒回路に圧縮機１を迂回して接続されたガスバイパス手段７、室外側熱交換器２の出側と圧縮機１の吸入側間の冷媒回路に絞り手段３および室内側熱交換器４を迂回して接続された液バイパス手段８等といったアクチュエータが配備されている。
また、熱源機Ａには、圧縮機１の吐出側における冷媒吐出圧力を検出する圧縮機吐出圧力検出手段９、圧縮機１の吸入側における冷媒圧力を検出する圧縮機吸入圧力検出手段１０、圧縮機１の吐出側における冷媒温度を検出する圧縮機吐出温度検知手段１１、圧縮機１の吸入側における冷媒温度を検出する圧縮機吸入温度検知手段１２、室内側熱交換器４の冷媒出側における冷媒温度を検出する凝縮器出口温度検知手段１３等といったセンサも配備されている。そして、制御装置１４により、各センサの検出値に基づいて各アクチュエータが連係制御されるようになっている。
【００１１】
ここで、制御装置１４による連係制御について説明する。まず、圧縮機１を含む熱源機Ａの適正な運転範囲のパラメータとして、圧縮機吐出温度、凝縮器出口サブクール、および、圧縮機吸入スーパーヒートをとる。ここで、凝縮機出口サブクールは凝縮器出口温度検知手段１３の検出温度と圧縮機吐出圧力検出手段９の検出圧力に対応する冷媒飽和温度との差より求められ、圧縮機吸入スーパーヒートは圧縮機吸入温度検知手段１２の検出温度と圧縮機吸入圧力検出手段１０の検出圧力に対応する冷媒飽和温度との差より求められる。
すなわち、凝縮器出口温度検知手段１３と圧縮機吐出圧力検出手段９と制御装置１４との組み合わせ構成が、室外側熱交換器（凝縮器）２の出側における冷媒サブクール量を検出する凝縮器出口サブクール検知手段の一例となる。また、圧縮機吸入温度検知手段１２と圧縮機吸入圧力検出手段１０と制御装置１４との組み合わせ構成が、圧縮機１の吸入側における冷媒スーパーヒート量を検出する圧縮機吸入スーパーヒート検知手段の一例となる。
【００１２】
また、各アクチュエータの動作による冷凍サイクルのモリエル線図上の変化を示すと、運転状況および制御量にもよるが、図２に示すようになる。ガスバイパス手段７の動作では、同図（ａ）に示すように、弁の開方向動作にて、圧縮機吐出温度低下、凝縮器出口サブクール減少、圧縮機吸入スーパーヒート増加、の方向に制御される。液バイパス手段８の動作では、同図（ｂ）に示すように、弁の開方向動作にて、圧縮機吐出温度低下、凝縮記出口サブクール増加、圧縮機吸入スーパーヒート減少、の方向に制御される。凝縮器熱交換量制御手段であるファン６の動作では、同図（ｃ）に示すように、ファン６の増速方向動作にて、圧縮機吐出温度低下、凝縮器出口サブクール増加、圧縮機吸入スーパーヒート減少、の方向に制御される。この場合、制御装置４によりファン６の風量を制御する構成が、室外側熱交換器２における冷媒の熱交換量を変化させる凝縮器熱交換量変化手段の一例となる。
このように、各アクチュエータの制御動作により、上記３つのパラメータはすべて変動する。したがって、１つのパラメータに一つのアクチュエータを対応させる従来の考え方では、制御変数が目標値に向けて収束せず揺れるといった振動的な制御になる可能性がある。そこで、下式を導入し、下式に基づく連係制御を実現する。
【００１３】
【数１】

【００１４】
ここで、式中のａないしｉは実験等で予め求めた関数である。
また、目標値―検出値としては最大値を規定することにより急激な制御量の変化を抑制するとともに、上式による制御を周期的に繰り返す。また、目標値としては許容できる範囲で幅を持たせ、制御動作の振動を抑制するようにした。
【００１５】
このように、制御装置１４の第１制御手段１４ａにより、各センサによるそれぞれの検出値が各センサ毎に予め設定されている所定の目標範囲内に収まるように、各アクチュエータを連係して制御することができる。すなわち、熱源機Ａと、蒸発器４および絞り手段３とが完全に自律分散制御される冷凍サイクルであっても、熱源機Ａ内で閉じたアクチュエータとセンサによる連係制御によって、蒸発能力の変化に伴い圧縮機１の運転状態が大幅に変化したり、冷凍能力の安定供給および圧縮機１の安全な運転範囲の確保ができなくなったり、保護制御により圧縮機１のサーモ発停頻度が増加したり、あるいは、蒸発温度低下によるデフロスト運転頻度が増加することに起因して室内温度変化が増大したりといった不具合を解消することができる。
また、インバータ等の容量制御による複雑な冷凍能力制御ではなく、ガスバイパスおよび液バイパスといった簡便な冷凍能力制御を実現することができる。
なお、ここでは圧縮機吐出圧力検出手段９の検出圧力を制御に用いたが、凝縮器２の中間部等で検出した高圧冷媒飽和温度を用いても、同様の制御ができることは言うまでもない。
【００１６】
実施の形態２．
図３ないし図５を用いて、実施の形態２を説明する。
図３において、１は圧縮機、２は室外側熱交換器、３は絞り装置、４は室内側熱交換器であり、これらは環状配置に連通して主冷媒回路を形成している。そして、圧縮機１、室外側熱交換器２等により熱源機Ａが構成され、絞り装置３、室内側熱交換器４等により室内機Ｂが構成される。５は冷媒配管であり、熱源機Ａと１台ないし複数台の室内機Ｂとを連通している。熱源機Ａは、上記のほかに、弁流路の切替えにより冷媒回路における冷媒の流れ方向を切替える第１四方弁１５を備えている。
室内機Ｂは、上記のほかに、室内側熱交換器４のガス冷媒側の冷媒回路に設けられてガス冷媒を加圧し単方向に流通させるガスポンプ等の冷媒加圧手段１６、冷媒加圧手段１６と並列に冷媒回路に配備されて冷媒加圧手段１６の未使用時に低圧損経路を形成する第１バイパス手段１８、弁流路の切替えにより冷媒回路における冷媒流れ方向を双方向に切替えて流通させる第２四方弁１７を備えている。冷媒加圧手段１６と第２四方弁１７は、第１四方弁１５と室内側熱交換器４の間の冷媒回路に配備されている。冷媒加圧手段１６の吐出側は第２四方弁１７の高圧側入口１７ａに接続されている。冷媒加圧手段１６の吸入側は第２四方弁１７の低圧側出口１７ｂに接続されている。室内機Ｂには、さらに、冷媒加圧手段１６の室内側熱交換器４側の冷媒圧力に対応した圧力相当値を検出する第１圧力検出手段１９、冷媒加圧手段１６の熱源機Ａ側の冷媒圧力に対応した圧力相当値を検出する第２圧力検出手段２０、および、室内環境温度の目標温度を設定するための室内環境温度設定手段（図示せず。以下同じ）がそれぞれ配備されている。
【００１７】
このように構成したことで、室内機Ｂにおける冷媒の流れ方向に応じて第２四方弁１７の流路を切替え制御することにより、冷媒加圧手段１６を常に加圧方向で働かせることができる。また、冷媒加圧手段１６が不要な場合には、第１バイパス手段１８を全開とすることで、圧力損失なしに、従来どおりの室内機Ｂとして動作させることができる。
【００１８】
次に、制御動作について図４に基づいて説明する。
図４（ａ）は冷房運転の場合を示している。図において、制御装置１４の第２制御手段１４ｂは、各々の室内機Ｂにおける室内環境温度設定手段の設定温度に基づく目標圧力値または実際の室内環境温度に基づく目標圧力値に向けて、第１圧力検出手段１９の検出圧力を近づけるように、冷媒加圧手段１６の加圧制御量を変化させる。
このように構成したことで、熱源機Ａにおける圧縮機１の吸入圧力に対応した冷媒飽和温度よりも低い蒸発温度を室内機Ｂ毎に実現でき、高い蒸発温度で良い室内機Ｂに合わせた熱源機Ａの動作により、その室内機Ｂでの冷え過ぎに起因するサーモ発停頻度の増大、室内デフロスト運転頻度の増大を抑制することができる。
【００１９】
図４（ｂ）は暖房運転の場合を示している。図において、制御装置１４の第２制御手段１４ｂは、各々の室内機Ｂにおける室内環境温度設定手段の設定温度値に基づく目標圧力値または実際の室内環境温度に基づく目標圧力値に向けて、第１圧力検出手段１９の検出圧力を近づけるように、冷媒加圧手段１６の加圧制御量を変化させる。
このように構成したことで、熱源機Ａにおける圧縮機１の吐出圧力に対応した冷媒飽和温度よりも高い凝縮温度を室内機Ｂ毎に実現でき、低い蒸発温度で良い室内機Ｂに合わせた熱源機Ａの動作により、その室内機Ｂでの暖め過ぎに起因するサーモ発停頻度の増大を抑制することができる。
【００２０】
次の制御動作につき、図５に基づいて説明する。
図５（ａ）は冷房（冷凍）運転の場合を示す。図において、制御装置１４の第３制御手段１４ｃは、熱源機Ａの圧縮機吸入圧力の目標値に各々の室内機Ｂに接続される冷媒配管５での圧力損失相当分を加えた目標圧力値に向けて、第２圧力検出手段２０の検出圧力を近づけるように、冷媒加圧手段１６の加圧制御量を変化させる。
このように構成したことで、熱源機Ａにおける圧縮機吸入圧力が低下して適正運転範囲を逸脱したり、冷媒回路の冷媒循環量が低下したり、あるいは、熱源機Ａ側から逆算して室内機Ｂでの蒸発圧力が上昇し室内側熱交換器４での空気と冷媒の温度差が減少したりするといったことがなく、室内側熱交換器４で要求される蒸発能力の不足を抑制できる。
【００２１】
図５（ｂ）は暖房運転の場合を示す。図において、制御装置１４の第３制御手段１４ｃは、熱源機Ａの圧縮機吐出圧力の目標値に各々の室内機Ｂに接続される冷媒配管５での圧力損失相当分を減算した目標圧力値に向けて、第２圧力検出手段２０の検出圧力を近づけるように、冷媒加圧手段１６の加圧制御量を変化させる。
このように構成したことで、熱源機Ａにおける圧縮機吐出圧力の上昇や圧縮機吐出温度の上昇によって適正運転範囲を逸脱したり、あるいは、熱源機Ａ側から逆算して室内機Ｂでの凝縮温度が低下して室内側熱交換器４での空気と冷媒の温度差が減少するといったことがなく、室内側熱交換器４で要求される凝縮能力が不足することを抑制できる。
【００２２】
実施の形態３．
図６ないし図８を用いて、実施の形態３を説明する。
図６において、１は圧縮機、２は室外側熱交換器、３は絞り装置、４は室内側熱交換器であり、これらは環状配置に連通して主冷媒回路を形成している。そして、圧縮機１、室外側熱交換器２等より熱源機Ａが構成され、絞り装置３、室内側熱交換器４等より室内機Ｂが構成される。５は冷媒配管であり、熱源機Ａと１台ないし複数台の室内機Ｂとを連通している。熱源機Ａは、上記のほかに、第１四方弁１５を備えている。室内機Ｂは、上記のほかに、室内側熱交換器４のガス冷媒側における冷媒回路に配備されてガス冷媒を減圧する冷媒減圧手段２１と、冷媒減圧手段２１と並列に冷媒回路に配備されて冷媒減圧手段２１の未使用時に低圧損経路を形成する第２バイパス手段２２を備えている。さらに、室内機Ｂは、冷媒減圧手段２１の室内側熱交換器４側における冷媒圧力に対応した圧力相当値を検出する第３圧力検出手段２３、冷媒減圧手段２１の熱源機Ａ側の冷媒回路における冷媒圧力を検出する第２圧力検出手段２４、室内環境温度を検出する室内環境温度検知手段２５、室内環境温度設定手段を備えている。
【００２３】
このように構成したことにより，室内機Ｂにおいて、冷媒減圧手段２１が不要な場合に、第２バイパス手段２２を全開とすることで、圧力損失なしに、従来どおりの室内機として動作することができる。
【００２４】
次に、制御動作に付き、図７に基づいて説明する。
図７（ａ）は冷房運転の場合を示している。図において、制御装置１４の第４制御手段１４ｄは、各々の室内機Ｂにおける室内環境温度設定手段の設定温度に基づく目標圧力値または実際の室内環境温度に基づく目標圧力値に向けて、第３圧力検出手段２３の検出圧力を近づけるように、冷媒減圧手段２１の減圧制御量を変化させる。
このように構成したことで、熱源機Ａにおける圧縮機１の吸入圧力に対応した冷媒飽和温度よりも高い蒸発温度を各々の室内機Ｂ毎に実現でき、低い蒸発温度の室内機Ｂに合わせた熱源機Ａの動作により、高い蒸発温度で良い室内機Ｂにおける冷え過ぎに起因したサーモ発停頻度の増大や室内デフロスト運転頻度の増大を抑制できる。
【００２５】
図７（ｂ）は暖房運転の場合を示す。図において、制御装置１４の第４制御手段１４ｄは、各々の室内機Ｂにおける室内環境温度設定手段の設定温度に基づく目標圧力値または実際の室内環境温度に基づく目標圧力値に向けて、第３圧力検出手段２３の検出圧力を近づけるように、冷媒減圧手段２１の減圧制御量を変化させる。
このように構成したことで、熱源機Ａにおける圧縮機吐出圧力に対応した冷媒飽和温度よりも低い凝縮圧力を各々の室内機Ｂ毎に実現でき、高い蒸発温度の室内機Ｂに合わせた熱源機Ａの動作により、低い凝縮温度で良い室内機Ｂにおける暖め過ぎに起因するサーモ発停頻度の増大を抑制できる。
【００２６】
次の制御動作に付き、図８に基づいて説明する。
図８は冷房（冷凍）運転の場合を示す。図において、各々の室内機Ｂにおける室内環境温度設定手段の設定値と室内環境温度検知手段２５の検出値との差が小さくなった場合に、制御装置１４の第５制御手段１４ｅは、室内機Ｂの蒸発能力を抑制するため、熱源機Ａにおける圧縮機吸入圧力に対応する目標圧力値を低下させる。さらに、第５制御手段１４ｅは第４圧力検出手段２４の検出圧力をその目標値に近づけるように、冷媒減圧手段２１の減圧制御量を変化させる。
このように構成したことで、熱源機Ａにおける圧縮機１の吸入圧力が低下して冷媒回路の冷媒循環量が抑制される。これにより、冷凍能力を抑制することができる。そして、室内機Ｂでの冷え過ぎに起因するサーモ発停頻度の増大や、室内デフロスト運転頻度の増大を抑制できる。
【００２７】
【発明の効果】
本発明は、室内側熱交換器のガス冷媒側に冷媒加圧手段を設けたことにより、接続配管での圧損等による室内側熱交換器で要求される凝縮能力や蒸発能力が不足することを抑制できる。そのうえ、複数台の室内機で要求される室内側熱交換器の凝縮温度または蒸発温度が異なる場合でも、目標温度を最高の凝縮温度や最低の蒸発温度に設定したことによる暖め過ぎや冷え過ぎ、あるいはそれらに伴うサーモ発停頻度の増加やデフロスト運転頻度の増加等による室内温度変化の増大を抑制することができる。
【図面の簡単な説明】
【図１】本発明の実施の形態１に係る冷凍サイクル装置の冷媒回路を示す構成図である。
【図２】実施の形態１の冷凍サイクル装置の動作を説明するためのものであって、（ａ）はガスバイパス手段を制御する場合のｐ−ｈ線図、（ｂ）は液バイパス手段を制御する場合のｐ−ｈ線図、（ｃ）は凝縮器熱交換量変化手段を制御する場合のｐ−ｈ線図である。
【図３】本発明の実施の形態２に係る冷凍サイクル装置の冷媒回路を示す構成図である。
【図４】実施の形態２の冷凍サイクル装置の動作を説明するためのものであって、（ａ）は冷房運転時のｐ−ｈ線図、（ｂ）は暖房運転時のｐ−ｈ線図である。
【図５】実施の形態２の冷凍サイクル装置の別の動作を説明するためのものであって、（ａ）は冷房運転時のｐ−ｈ線図、（ｂ）は暖房運転時のｐ−ｈ線図である。
【図６】本発明の実施の形態３に係る冷凍サイクル装置の冷媒回路を示す構成図である。
【図７】実施の形態３の冷凍サイクル装置の動作を説明するためのものであって、（ａ）は冷房運転時のｐ−ｈ線図、（ｂ）は暖房運転時のｐ−ｈ線図である。
【図８】実施の形態３の冷凍サイクル装置における冷房運転時の別の動作を説明するためのｐ−ｈ線図である。
【図９】従来例の冷媒回路を示す構成図である。
【符号の説明】
１圧縮機、２室外側熱交換器（凝縮器）、３絞り装置、４室内側熱交換器（蒸発器）、５冷媒配管、６ファン、７ガスバイパス手段、８液バイパス手段、９圧縮機吐出圧力検出手段、１０圧縮機吸入圧力検出手段、１１圧縮機吐出温度検知手段、１２圧縮機吸入温度検知手段、１３凝縮器出口温度検知手段、１４制御装置、１４ａ第１制御手段、１４ｂ第２制御手段、１４ｃ第３制御手段、１４ｄ第４制御手段、１４ｅ第５制御手段、１５第１四方弁、１６冷媒加圧手段、１７第２四方弁、１７ａ高圧側入口、１７ｂ低圧側出口、１８第１バイパス手段、１９第１圧力検出手段、２０第２圧力検出手段、２１冷媒減圧手段、２２第２バイパス手段、２３第３圧力検出手段、２４第４圧力検出手段、２５室内環境温度検知手段、Ａ熱源機、Ｂ室内機。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a refrigeration cycle apparatus used for a refrigerator or an air conditioner, and particularly relates to protection of a compressor and ensuring of an appropriate refrigerant temperature in each indoor unit.
[0002]
[Prior art]
A conventional refrigeration cycle apparatus is generally configured as shown in FIG. In the figure, 1 is a compressor, 2 is a condenser, 3 is a throttling device, and 4 is an evaporator, which communicate with an annular arrangement to form a main refrigerant circuit. And the heat source machine A is comprised by the compressor 1, the condenser 2, etc., and the indoor unit B is comprised by the expansion apparatus 3, the evaporator 4, etc. FIG. Reference numeral 5 denotes a refrigerant pipe that communicates the heat source unit A with one or more indoor units B.
In addition to the above, the heat source machine A is provided with actuators such as a fan 6, a gas bypass means 7, and a liquid bypass means 8 as condenser heat exchange amount adjusting means. Sensors such as a compressor discharge pressure detecting means 9, a compressor suction pressure detecting means 10, a compressor discharge temperature detecting means 11 are also provided. Then, the control means 14A individually controls each actuator so that the detection value of each sensor does not deviate from the permissible range. For example, the air volume of the fan 6 to the condenser 2 is controlled based on the refrigerant discharge pressure detected by the compressor discharge pressure detection means 9, and the gas is determined based on the refrigerant suction pressure detected by the compressor suction pressure detection means 10. The bypass means 7 was controlled to open and close, and the liquid bypass means 8 was controlled to open and close based on the refrigerant discharge temperature detected by the compressor discharge temperature detecting means 11. Further, in the indoor unit B, an operation is performed in which the evaporation pressure of the evaporator 4 is uniquely determined based on the pressure corresponding to the refrigerant suction pressure of the heat source unit A. The conventional refrigeration cycle apparatus is configured as described above so that the environment in which the indoor unit B is installed is frozen or air-conditioned while performing protection control for maintaining an appropriate operating range of the compressor 1. It was.
[0003]
[Problems to be solved by the invention]
Since the conventional refrigeration cycle apparatus is configured as described above, there are the following problems.
In particular, in the above-described refrigeration cycle apparatus in which the heat source unit A, the evaporator 4 and the throttle means 3 are autonomously distributed and controlled individually, the operating state of the compressor 1 changes significantly as the evaporation capacity changes. There is. In such a case, the stable supply of the refrigeration capacity and the safe operation range of the compressor 1 cannot be ensured, the frequency of the thermo-start / stop of the compressor 1 due to protection control is increased, or the evaporation temperature is lowered. In some cases, the increase in the indoor temperature change was caused by the increase in the defrost operation frequency.
Moreover, the condensation capacity or the evaporation capacity required for the indoor heat exchanger 4 may be insufficient due to a pressure loss in the refrigerant pipe 5 or the like.
Alternatively, when the condensation temperatures or evaporation temperatures required by the plurality of indoor heat exchangers 4 are different, for example, the temperature is too warm or too cold due to the setting of the highest condensation temperature and the lowest evaporation temperature, or accompanying it. In some cases, the indoor temperature change increased due to an increase in the frequency of starting and stopping the thermo and an increase in the frequency of defrost operation.
In addition, simple refrigeration capacity control means has been demanded instead of complicated refrigeration capacity control by capacity control using an inverter or the like.
[0004]
[Means for Solving the Problems]
The refrigeration cycle apparatus according to the present invention includes a refrigerant pipe that connects a heat source device that connects a compressor, an outdoor heat exchanger, and the like, and a plurality of indoor units that are connected to a throttle means, an indoor heat exchanger, and the like. An evaporating temperature equal to or lower than the refrigerant saturation temperature corresponding to the suction pressure of the compressor by providing a refrigerant pressurizing unit that pressurizes the gas refrigerant in the refrigerant circuit on the gas refrigerant side of the indoor heat exchanger. The evaporation temperature of the indoor side heat exchanger required by the plurality of indoor units is made different.
[0005]
Further, the refrigeration cycle apparatus according to the present invention is a refrigerant comprising a heat source device connected to a compressor, an outdoor heat exchanger, etc., and a plurality of indoor units connected to a throttle means, an indoor heat exchanger, etc. The refrigerant circuit is connected by piping, and the refrigerant circuit on the gas refrigerant side of the indoor heat exchanger is provided with a refrigerant pressurizing means for pressurizing the gas refrigerant, so that the refrigerant saturation temperature or higher corresponding to the discharge pressure of the compressor is exceeded. The condensation temperature is realized, and the condensation temperatures of the indoor heat exchangers required for the plurality of indoor units are made different.
[0006]
Further, in parallel with the refrigerant pressurizing means, a first bypass means for forming a low pressure loss path when the refrigerant pressurizing means is not used is provided.
[0007]
In addition, a refrigerant pressurizing means that pressurizes the refrigerant and circulates in one direction and a second four-way valve are arranged between the first four-way valve provided on the discharge side of the compressor and the indoor heat exchanger, The discharge side of the refrigerant pressurizing means is connected to the high pressure side inlet of the second four-way valve, the suction side of the refrigerant pressurizing means is connected to the low pressure side outlet of the second four-way valve, and the second four-way valve In this configuration, the refrigerant is switched in both directions by switching the flow path.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
1 is a configuration diagram illustrating a refrigerant circuit of a refrigeration cycle apparatus according to Embodiment 1. FIG. In FIG. 1, 1 is a compressor, 2 is an outdoor heat exchanger (condenser at the time of cooling), 3 is an expansion device, 4 is an indoor heat exchanger (an evaporator at the time of cooling), and these are annularly arranged. To form a main refrigerant circuit. Here, the heat source unit A is configured by the compressor 1, the condenser 2, and the like, and the indoor unit B is configured by the expansion device 3, the evaporator 4, and the like. Reference numeral 5 denotes a refrigerant pipe that communicates the heat source unit A with one or more indoor units B. In addition to the above, the heat source A includes a fan 6 as a condenser heat exchange amount adjusting unit, and a gas bypass unit that bypasses the compressor 1 and is connected to a refrigerant circuit between the discharge side and the suction side of the compressor 1. 7. Actuators such as a liquid bypass means 8 and the like connected to the refrigerant circuit between the outlet side of the outdoor heat exchanger 2 and the suction side of the compressor 1 by bypassing the throttle means 3 and the indoor heat exchanger 4 are provided. ing.
The heat source machine A includes a compressor discharge pressure detecting means 9 for detecting the refrigerant discharge pressure on the discharge side of the compressor 1, a compressor suction pressure detecting means 10 for detecting the refrigerant pressure on the suction side of the compressor 1, and a compression. Compressor discharge temperature detection means 11 for detecting the refrigerant temperature on the discharge side of the machine 1, compressor intake temperature detection means 12 for detecting the refrigerant temperature on the suction side of the compressor 1, and on the refrigerant outlet side of the indoor heat exchanger 4 Sensors such as a condenser outlet temperature detecting means 13 for detecting the refrigerant temperature are also provided. Then, the actuator is linked and controlled by the control device 14 based on the detection value of each sensor.
[0011]
Here, the linkage control by the control device 14 will be described. First, the compressor discharge temperature, the condenser outlet subcool, and the compressor suction superheat are taken as parameters of an appropriate operating range of the heat source apparatus A including the compressor 1. Here, the condenser outlet subcool is obtained from the difference between the detected temperature of the condenser outlet temperature detecting means 13 and the refrigerant saturation temperature corresponding to the detected pressure of the compressor discharge pressure detecting means 9, and the compressor suction superheat is the compressor. It is obtained from the difference between the detected temperature of the intake temperature detecting means 12 and the refrigerant saturation temperature corresponding to the detected pressure of the compressor intake pressure detecting means 10.
That is, the condenser outlet temperature detecting means 13, the compressor discharge pressure detecting means 9 and the control device 14 detect the refrigerant subcooling amount on the outlet side of the outdoor heat exchanger (condenser) 2. This is an example of subcool detection means. The compressor suction temperature detection means 12, the compressor suction pressure detection means 10, and the control device 14 are examples of compressor suction superheat detection means for detecting the refrigerant superheat amount on the suction side of the compressor 1. It becomes.
[0012]
Further, changes on the Mollier diagram of the refrigeration cycle due to the operation of each actuator are as shown in FIG. 2 depending on the operation state and the control amount. In the operation of the gas bypass means 7, as shown in FIG. 5A, the valve opening direction operation is controlled in the direction of decreasing the compressor discharge temperature, decreasing the condenser outlet subcool, and increasing the compressor suction superheat. The In the operation of the liquid bypass means 8, as shown in FIG. 5B, the valve discharge direction operation is controlled in the direction of the compressor discharge temperature decrease, the condensation outlet subcool increase, and the compressor suction superheat decrease. The In the operation of the fan 6 which is the condenser heat exchange amount control means, as shown in FIG. 5C, the operation of the fan 6 in the speed increasing direction reduces the compressor discharge temperature, increases the condenser outlet subcool, and sucks the compressor. Controlled in the direction of superheat reduction. In this case, the configuration in which the air volume of the fan 6 is controlled by the control device 4 is an example of a condenser heat exchange amount changing unit that changes the heat exchange amount of the refrigerant in the outdoor heat exchanger 2.
As described above, all of the above three parameters vary depending on the control operation of each actuator. Therefore, according to the conventional idea of associating one actuator with one parameter, there is a possibility that the control variable vibrates such that the control variable does not converge toward the target value and swings. Therefore, the following formula is introduced to realize linkage control based on the following formula.
[0013]
[Expression 1]

[0014]
Here, a to i in the equation are functions obtained in advance through experiments or the like.
Further, by defining a maximum value as the target value-detection value, a rapid change in the control amount is suppressed, and the control according to the above equation is periodically repeated. Further, the target value has an allowable range to suppress the vibration of the control operation.
[0015]
In this way, the first control means 14a of the control device 14 controls the actuators in association with each other so that the detection values of the sensors are within a predetermined target range set in advance for each sensor. be able to. That is, even in a refrigeration cycle in which the heat source unit A, the evaporator 4 and the throttling means 3 are completely autonomously distributed controlled, the evaporation capacity can be changed by the linkage control by the actuator and sensor closed in the heat source unit A. As a result, the operating state of the compressor 1 changes drastically, it becomes impossible to ensure a stable supply of refrigeration capacity and a safe operating range of the compressor 1, or the frequency of thermo on / off of the compressor 1 increases due to protection control. Alternatively, it is possible to eliminate problems such as an increase in indoor temperature change due to an increase in the defrosting operation frequency due to a decrease in evaporation temperature.
In addition, simple refrigeration capacity control such as gas bypass and liquid bypass can be realized instead of complicated refrigeration capacity control by capacity control of an inverter or the like.
Although the detected pressure of the compressor discharge pressure detecting means 9 is used for the control here, it goes without saying that the same control can be performed even if the high-pressure refrigerant saturation temperature detected at the intermediate portion of the condenser 2 or the like is used.
[0016]
Embodiment 2. FIG.
The second embodiment will be described with reference to FIGS.
In FIG. 3, 1 is a compressor, 2 is an outdoor heat exchanger, 3 is an expansion device, 4 is an indoor heat exchanger, and these communicate with an annular arrangement to form a main refrigerant circuit. And the heat source machine A is comprised by the compressor 1, the outdoor side heat exchanger 2, etc., and the indoor unit B is comprised by the expansion apparatus 3, the indoor side heat exchanger 4, etc. Reference numeral 5 denotes a refrigerant pipe that communicates the heat source unit A with one or more indoor units B. In addition to the above, the heat source machine A includes a first four-way valve 15 that switches the flow direction of the refrigerant in the refrigerant circuit by switching the valve flow path.
In addition to the above, the indoor unit B is provided in the refrigerant circuit on the gas refrigerant side of the indoor heat exchanger 4, and pressurizes the gas refrigerant to circulate in a unidirectional manner. The first bypass means 18 is arranged in the refrigerant circuit in parallel with the refrigerant pressure line 16 to form a low-pressure loss path when the refrigerant pressurizing means 16 is not used, and the refrigerant flow direction in the refrigerant circuit is switched bidirectionally by switching the valve flow path. A second four-way valve 17 is provided. The refrigerant pressurizing means 16 and the second four-way valve 17 are arranged in the refrigerant circuit between the first four-way valve 15 and the indoor heat exchanger 4. The discharge side of the refrigerant pressurizing means 16 is connected to the high pressure side inlet 17 a of the second four-way valve 17. The suction side of the refrigerant pressurizing means 16 is connected to the low pressure side outlet 17 b of the second four-way valve 17. The indoor unit B further includes a first pressure detecting unit 19 that detects a pressure equivalent value corresponding to the refrigerant pressure on the indoor heat exchanger 4 side of the refrigerant pressurizing unit 16, and the heat source unit A side of the refrigerant pressurizing unit 16. The second pressure detecting means 20 for detecting the pressure equivalent value corresponding to the refrigerant pressure of the room, and the indoor environment temperature setting means (not shown; the same applies hereinafter) for setting the target temperature of the indoor environment temperature are respectively provided. Yes.
[0017]
With this configuration, the refrigerant pressurizing means 16 can always be operated in the pressurizing direction by switching and controlling the flow path of the second four-way valve 17 according to the flow direction of the refrigerant in the indoor unit B. When the refrigerant pressurizing means 16 is not necessary, the first bypass means 18 is fully opened, so that it can be operated as a conventional indoor unit B without pressure loss.
[0018]
Next, the control operation will be described with reference to FIG.
FIG. 4A shows the case of the cooling operation. In the figure, the second control means 14b of the control device 14 is directed toward the target pressure value based on the set temperature of the indoor environment temperature setting means in each indoor unit B or the target pressure value based on the actual indoor environment temperature. The pressurization control amount of the refrigerant pressurizing unit 16 is changed so that the detected pressure of the pressure detecting unit 19 is close.
With such a configuration, an evaporation temperature lower than the refrigerant saturation temperature corresponding to the suction pressure of the compressor 1 in the heat source unit A can be realized for each indoor unit B, and the heat source matched to the indoor unit B that requires a high evaporation temperature By the operation of the machine A, it is possible to suppress an increase in the frequency of thermo-start / stop and the increase in the frequency of the indoor defrost operation due to the overcooling in the indoor unit B.
[0019]
FIG. 4B shows the case of heating operation. In the figure, the second control means 14b of the control device 14 sets the target pressure value based on the set temperature value of the indoor environment temperature setting means in each indoor unit B or the target pressure value based on the actual indoor environment temperature. The pressurization control amount of the refrigerant pressurizing means 16 is changed so that the detected pressure of the 1 pressure detecting means 19 approaches.
By comprising in this way, the condensation temperature higher than the refrigerant | coolant saturation temperature corresponding to the discharge pressure of the compressor 1 in the heat source A can be implement | achieved for every indoor unit B, and the heat source match | combined with the indoor unit B with which low evaporation temperature is good Due to the operation of the machine A, it is possible to suppress an increase in the frequency of starting and stopping the thermo, which is caused by overheating in the indoor unit B.
[0020]
The next control operation will be described with reference to FIG.
FIG. 5A shows the case of cooling (freezing) operation. In the figure, the third control means 14c of the control device 14 is a target pressure value obtained by adding the equivalent value of the pressure loss in the refrigerant pipe 5 connected to each indoor unit B to the target value of the compressor suction pressure of the heat source unit A. The pressure control amount of the refrigerant pressurizing means 16 is changed so that the detected pressure of the second pressure detecting means 20 approaches.
With this configuration, the compressor suction pressure in the heat source unit A decreases and deviates from the proper operating range, or the refrigerant circulation amount in the refrigerant circuit decreases, or the room is calculated backward from the heat source unit A side. The evaporation pressure in the machine B does not increase and the temperature difference between the air and the refrigerant in the indoor heat exchanger 4 does not decrease, and the shortage of evaporation capacity required in the indoor heat exchanger 4 can be suppressed. .
[0021]
FIG. 5B shows the case of heating operation. In the figure, the third control means 14c of the control device 14 is a target pressure value obtained by subtracting the pressure loss equivalent in the refrigerant pipe 5 connected to each indoor unit B from the target value of the compressor discharge pressure of the heat source unit A. The pressure control amount of the refrigerant pressurizing means 16 is changed so that the detected pressure of the second pressure detecting means 20 approaches.
With this configuration, the proper operating range deviates due to an increase in the compressor discharge pressure and the compressor discharge temperature in the heat source unit A, or the condensation in the indoor unit B is calculated backward from the heat source unit A side. The temperature does not decrease and the temperature difference between the air and the refrigerant in the indoor heat exchanger 4 does not decrease, and the condensing capacity required in the indoor heat exchanger 4 can be suppressed from being insufficient.
[0022]
Embodiment 3 FIG.
The third embodiment will be described with reference to FIGS.
In FIG. 6, 1 is a compressor, 2 is an outdoor heat exchanger, 3 is an expansion device, 4 is an indoor heat exchanger, and these communicate with an annular arrangement to form a main refrigerant circuit. And the heat source machine A is comprised from the compressor 1, the outdoor side heat exchanger 2, etc., and the indoor unit B is comprised from the expansion apparatus 3, the indoor side heat exchanger 4, etc. Reference numeral 5 denotes a refrigerant pipe that communicates the heat source unit A with one or more indoor units B. The heat source machine A includes the first four-way valve 15 in addition to the above. In addition to the above, the indoor unit B is provided in the refrigerant circuit on the gas refrigerant side of the indoor heat exchanger 4 and is provided in the refrigerant circuit in parallel with the refrigerant depressurization means 21 that decompresses the gas refrigerant. And a second bypass means 22 for forming a low pressure loss path when the refrigerant decompression means 21 is not used. Furthermore, the indoor unit B includes a third pressure detection unit 23 that detects a pressure equivalent value corresponding to the refrigerant pressure on the indoor heat exchanger 4 side of the refrigerant decompression unit 21, and a refrigerant circuit on the heat source unit A side of the refrigerant decompression unit 21. Are provided with second pressure detecting means 24 for detecting the refrigerant pressure, indoor environment temperature detecting means 25 for detecting the indoor environment temperature, and indoor environment temperature setting means.
[0023]
With this configuration, in the indoor unit B, when the refrigerant decompression unit 21 is unnecessary, the second bypass unit 22 is fully opened so that it can operate as a conventional indoor unit without pressure loss. it can.
[0024]
Next, the control operation will be described with reference to FIG.
FIG. 7A shows the case of the cooling operation. In the figure, the fourth control means 14d of the control device 14 sets the third pressure toward the target pressure value based on the set temperature of the indoor environment temperature setting means in each indoor unit B or the target pressure value based on the actual indoor environment temperature. The depressurization control amount of the refrigerant depressurizing means 21 is changed so that the detected pressure of the pressure detecting means 23 approaches.
With this configuration, an evaporation temperature higher than the refrigerant saturation temperature corresponding to the suction pressure of the compressor 1 in the heat source unit A can be realized for each indoor unit B, and is adjusted to the indoor unit B having a low evaporation temperature. By the operation of the heat source unit A, it is possible to suppress an increase in the frequency of thermo on / off and an increase in the frequency of the indoor defrost operation due to overcooling in the indoor unit B that may have a high evaporation temperature.
[0025]
FIG. 7B shows the case of heating operation. In the figure, the fourth control means 14d of the control device 14 sets the third pressure toward the target pressure value based on the set temperature of the indoor environment temperature setting means in each indoor unit B or the target pressure value based on the actual indoor environment temperature. The depressurization control amount of the refrigerant depressurizing means 21 is changed so that the detected pressure of the pressure detecting means 23 approaches.
With this configuration, a condensing pressure lower than the refrigerant saturation temperature corresponding to the compressor discharge pressure in the heat source unit A can be realized for each indoor unit B, and the heat source unit adapted to the indoor unit B having a high evaporation temperature By the operation of A, it is possible to suppress an increase in the frequency of starting and stopping the thermo, which is caused by excessive warming in the indoor unit B that requires a low condensation temperature.
[0026]
The following control operation will be described with reference to FIG.
FIG. 8 shows the case of cooling (freezing) operation. In the figure, when the difference between the set value of the indoor environment temperature setting means and the detected value of the indoor environment temperature detection means 25 in each indoor unit B becomes small, the fifth control means 14e of the control device 14 In order to suppress the evaporation capability of B, the target pressure value corresponding to the compressor suction pressure in the heat source device A is reduced. Further, the fifth control means 14e changes the pressure reduction control amount of the refrigerant pressure reducing means 21 so that the detected pressure of the fourth pressure detection means 24 approaches the target value.
With this configuration, the suction pressure of the compressor 1 in the heat source device A is reduced, and the refrigerant circulation amount in the refrigerant circuit is suppressed. Thereby, refrigerating capacity can be suppressed. And the increase in the frequency of thermo on / off resulting from the overcooling in the indoor unit B and the increase in the indoor defrost operation frequency can be suppressed.
[0027]
【The invention's effect】
According to the present invention, by providing the refrigerant pressurizing means on the gas refrigerant side of the indoor heat exchanger, the condensing capacity and the evaporation capacity required for the indoor heat exchanger due to pressure loss in the connection pipe are insufficient. Can be suppressed. Moreover, even when the condensation temperature or evaporation temperature of the indoor heat exchanger required by multiple indoor units is different, the target temperature is set too high or too low due to the setting of the highest condensation temperature or lowest evaporation temperature. Or the increase of the indoor temperature change by the increase in the thermo start / stop frequency accompanying them, the increase in the defrost operation frequency, etc. can be suppressed.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a refrigerant circuit of a refrigeration cycle apparatus according to Embodiment 1 of the present invention.
2A and 2B are diagrams for explaining the operation of the refrigeration cycle apparatus according to the first embodiment, wherein FIG. 2A is a ph diagram for controlling the gas bypass means, and FIG. 2B is a liquid bypass means. A ph diagram in the case of controlling, (c) is a ph diagram in the case of controlling the condenser heat exchange amount changing means.
FIG. 3 is a configuration diagram showing a refrigerant circuit of a refrigeration cycle apparatus according to Embodiment 2 of the present invention.
4A and 4B are diagrams for explaining the operation of the refrigeration cycle apparatus according to the second embodiment, wherein FIG. 4A is a ph diagram during cooling operation, and FIG. 4B is a ph diagram during heating operation. FIG.
5A and 5B are diagrams for explaining another operation of the refrigeration cycle apparatus according to the second embodiment, where FIG. 5A is a ph diagram during cooling operation, and FIG. 5B is p- during heating operation. FIG.
FIG. 6 is a configuration diagram showing a refrigerant circuit of a refrigeration cycle apparatus according to Embodiment 3 of the present invention.
7A and 7B are diagrams for explaining the operation of the refrigeration cycle apparatus according to Embodiment 3, wherein FIG. 7A is a ph diagram during cooling operation, and FIG. 7B is a ph diagram during heating operation. FIG.
FIG. 8 is a ph diagram for explaining another operation during cooling operation in the refrigeration cycle apparatus of the third embodiment.
FIG. 9 is a configuration diagram showing a conventional refrigerant circuit.
[Explanation of symbols]
1 compressor, 2 outdoor heat exchanger (condenser), 3 expansion device, 4 indoor heat exchanger (evaporator), 5 refrigerant pipe, 6 fan, 7 gas bypass means, 8 liquid bypass means, 9 compressor Discharge pressure detection means, 10 Compressor suction pressure detection means, 11 Compressor discharge temperature detection means, 12 Compressor suction temperature detection means, 13 Condenser outlet temperature detection means, 14 Control device, 14a First control means, 14b Second Control means, 14c Third control means, 14d Fourth control means, 14e Fifth control means, 15 First four-way valve, 16 Refrigerant pressurizing means, 17 Second four-way valve, 17a High pressure side inlet, 17b Low pressure side outlet, 18 First bypass means, 19 First pressure detection means, 20 Second pressure detection means, 21 Refrigerant decompression means, 22 Second bypass means, 23 Third pressure detection means, 24 Fourth pressure detection means, 25 Indoor environment temperature detection Means, A heat source unit, B indoor unit.

Claims

In the refrigeration cycle apparatus in which a heat source device formed by connecting a compressor, an outdoor heat exchanger, and the like, and a plurality of indoor units formed by connecting a throttle means, an indoor heat exchanger, etc. are connected by a refrigerant pipe.
The refrigerant circuit on the gas refrigerant side of the indoor heat exchanger is provided with a refrigerant pressurizing unit that pressurizes the gas refrigerant, thereby realizing an evaporation temperature equal to or lower than a refrigerant saturation temperature corresponding to the suction pressure of the compressor, A refrigeration cycle apparatus characterized in that the evaporating temperature of the indoor side heat exchanger required for the indoor unit is different .

In the refrigeration cycle apparatus in which a heat source device formed by connecting a compressor, an outdoor heat exchanger, and the like, and a plurality of indoor units formed by connecting a throttle means, an indoor heat exchanger, etc. are connected by a refrigerant pipe.
The refrigerant circuit on the gas refrigerant side of the indoor heat exchanger is provided with a refrigerant pressurizing unit that pressurizes the gas refrigerant, thereby realizing a condensation temperature equal to or higher than the refrigerant saturation temperature corresponding to the discharge pressure of the compressor. A refrigeration cycle apparatus characterized in that the condensation temperature of the indoor side heat exchanger required for the indoor unit of the base is different .

3. The refrigeration cycle apparatus according to claim 1, wherein a first bypass unit that forms a low-pressure loss path when the refrigerant pressurizing unit is not used is provided in parallel with the refrigerant pressurizing unit .

A refrigerant pressurizing means that pressurizes the refrigerant and circulates in one direction and a second four-way valve are disposed between the first four-way valve provided on the discharge side of the compressor and the indoor heat exchanger, and the refrigerant The discharge side of the pressurizing means is connected to the high pressure side inlet of the second four-way valve, the suction side of the refrigerant pressurizing means is connected to the low pressure side outlet of the second four-way valve, and the flow of the second four-way valve The refrigeration cycle apparatus according to any one of claims 1 and 2, wherein the refrigerant is bidirectionally switched to flow through path switching .