JP2004060602A - Compressor for refrigerating cycle device and refrigerating cycle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compressor capable of performing a highly efficient operation while avoiding such problems with a compressor for a refrigerating cycle device that, since the ambient temperature of electrically moving elements is raised, the insulators of the electrically moving elements are deteriorated and the reliability of the compressor is lowered in the compressor for the refrigerating cycle device in which CO<SB>2</SB>refrigerant is used, at least compression elements and electrically moving elements are stored in a closed container, and a pressure in the closed container is generally the same as a high-pressure side pressure in a refrigerating cycle, and a refrigerating cycle device using the compressor. <P>SOLUTION: This compressor uses a refrigerating machine oil formed mainly of at least one of a mineral oil based oil, an alkyl benzene oil, and a mixture thereof. The insulators of the electrically moving elements are formed of at least one of polyvinyl formal, polyphenylene sulfide, polyester imide, polyamide, polyamide imide, and polyimide. Also the refrigerating cycle device using the compressor can be provided. <P>COPYRIGHT: (C)2004,JPO

Description

【００１９】
表１から明らかなように、電動要素１３の雰囲気温度が上昇する密閉容器１０内が冷凍サイクルにおける高圧側圧力と略同圧力である圧縮機であっても、絶縁材料として、従来、用いられてきたポリエチレンテレフタレート、ポリブチレンテレルタレート、ポリエチレンナフタレートなどより、耐熱性に優れたポリビニルホルマール、ポリフェニレンサルファイド、ポリエステルイミド、ポリアミド、ポリアミドイミド、ポリイミドなどを使用すると、絶縁材料が変質し、圧縮機の信頼性を低下させるといった問題が生じることがない。
【００２０】
したがって、密閉容器１０内を冷凍サイクルにおける高圧側圧力と略同圧力とし、電動要素１３の絶縁材料をポリビニルホルマール、ポリフェニレンサルファイド、ポリエステルイミド、ポリアミド、ポリアミドイミド、ポリイミドのうちの少なくとも１つとすることで、信頼性の低下を回避しつつ、高効率な圧縮機を実現できる。
【００２１】
さらに、表１から明らかなように、絶縁材料の変質をさらに低減し信頼性の低下を回避しつつ高効率な圧縮機を実現する上で、冷凍機油１４に含まれる水分の重量含有率は好ましくは１００重量ｐｐｍ以下、より好ましくは５０重量ｐｐｍ以下とするのが良い。また、冷凍機油１４に含まれる水分の重量含有率を好ましくは１００重量ｐｐｍ以下、より好ましくは５０重量ｐｐｍ以下とするためには、表２から明らかなように吸湿性の小さい、パラフィン油やナフテン油などの鉱油系油、アルキルベンゼン油およびそれらの混合物から選ばれるいずれか一つを主成分とした冷凍機油１４を用いることで水分管理が容易となる。
【００２２】
【表２】

【００２３】
よって、二酸化炭素を冷媒として用い、少なくとも圧縮要素と電動要素とを密閉容器内に収納し、かつ、鉱油系油、アルキルベンゼン油およびそれらの混合物から選ばれるいずれか一つを主成分とする冷凍機油を封入した冷凍サイクル装置用圧縮機において、前記密閉容器内が冷凍サイクルにおける高圧側圧力と略同圧力であり、前記電動要素の絶縁材料がポリビニルホルマール、ポリフェニレンサルファイド、ポリエステルイミド、ポリアミド、ポリアミドイミド、ポリイミドのうちの少なくとも１つからなることを特徴とする圧縮機は、信頼性の低下を回避しつつ高効率な圧縮機として価値あるものである。なお、冷凍機油による摺動損失を減らすために冷凍機油の粘度を適切に設定することが好ましい。ＣＯ_２冷媒は上記の冷凍機油への溶け込み量が少ない。従って、上記の冷凍機油については、４０℃での動粘度を４０ｍｍ^２／ｓ以下に保つことが好ましい。
【００２４】
以上のような本発明の冷凍サイクル装置用圧縮機は、圧縮機、放熱器、減圧器、吸熱器を接続した冷凍サイクル装置における圧縮機として用いられる。冷凍サイクル装置が圧縮機と吸熱器との間の冷媒と、放熱器と減圧器との間の冷媒を熱交換させる内部熱交換器をさらに備えている場合、圧縮機の冷媒吐出温度はさらに上昇する傾向になるため、本発明の冷凍サイクル装置用圧縮機を使用することの効果はより高くなる。
【００２５】
また、二酸化炭素を冷媒として用い、少なくとも、圧縮機、放熱器、減圧器、吸熱器を接続した冷凍サイクル装置において、前記圧縮機の冷媒吐出温度を検知する吐出温度検知器と、前記吐出温度検知器が検知した冷媒吐出温度に応じて前記減圧器の開度を操作し冷媒吐出温度を調整する減圧器吐出温度制御器と、前記放熱器の冷媒出口温度を検知する出口温度検知器と、前記出口温度検知器が検知した冷媒出口温度に応じて前記減圧器の開度を操作し高圧を調整する減圧器最適高圧制御器と、前記吐出温度検知器が検知した冷媒吐出温度に応じて前記減圧器吐出温度制御器と前記減圧器最適高圧制御器とを切り替えて前記減圧器の開度を操作する減圧器開度操作器と、前記吸熱器の冷媒蒸発温度を検知する蒸発温度検知器と、前記蒸発温度検知器が検知した冷媒蒸発温度に応じて前記圧縮機の回転数を操作し能力を調整する圧縮機能力制御器とを備えたことを特徴とする冷凍サイクル装置における圧縮機として、本発明の圧縮機を用いてもよい。この冷凍サイクル装置は、減圧器吐出温度制御器、減圧器最適高圧制御器、減圧器開度操作器、圧縮機能力制御器によって減圧器と圧縮機を適正に制御することで、利用者等から要求された能力に応じ、かつ、効率の高い状態で運転を維持しながら、圧縮機の電動要素の絶縁材料が変質するほどに圧縮機の冷媒吐出温度が上昇することを防止した運転が実現できるものであり、このような冷凍サイクル装置に本発明の圧縮機を用いれば、導電要素の絶縁材料の変質による信頼性の低下は、より確実に阻止できる（以下、この冷凍サイクル装置を実施の形態Ａと位置付ける）。
【００２６】
図２は、この冷凍サイクル装置の概略を示す構成図である。
図２の冷凍サイクル装置は、ＣＯ_２冷媒を使用し、圧縮機２１、放熱器２２、低圧側流路２３ａと高圧側流路２３ｂが熱交換するように構成された内部熱交換器２３、減圧器２４、吸熱器２５を基本構成要素としている。なお、内部熱交換器２３の低圧側流路２３ａは吸熱器２５〜圧縮機２１吸入の間の冷媒が流れるように構成されており、高圧側流路２３ｂは放熱器２２〜減圧器２４の間の冷媒が流れるように構成されている。
図２において、３１は圧縮機２１の冷媒吐出温度を検知する吐出温度検知器、３２は吐出温度検知器３１で検知された冷媒吐出温度が設定温度となるように減圧器２４の開度を制御する減圧器吐出温度制御器、３３は放熱器２２の冷媒出口温度を検知する出口温度検知器、３４は出口温度検知器３３で検知された冷媒出口温度からＣＯＰ（Ｃｏｅｆｆｉｃｉｅｎｔ　ｏｆ　Ｐｅｒｆｏｒｍａｎｃｅ）が最大となる冷凍サイクルにおける高圧側圧力（圧縮機２１吐出〜放熱器２２〜内部熱交換器の高圧側流路２３ｂ〜減圧器２４入口）（以下、最適高圧という）を演算する最適高圧演算器、３５は高圧側圧力を検知する高圧検知器、３６は高圧検知器３５で検知された高圧側圧力が最適高圧演算器３４で演算された最適高圧となるように減圧器２４の開度を制御する減圧器最適高圧制御器、３７は減圧器吐出温度制御器３２と減圧器最適高圧制御器３６の出力を吐出温度検知器３１で検知された冷媒吐出温度に応じて切り替えあるいは融合して減圧器２４の開度を操作する減圧器開度操作器である。また、４１は吸熱器２５での冷媒蒸発温度を検知する蒸発温度検知器、４２は蒸発温度検知器４１で検知された冷媒蒸発温度が、吸熱器２５が凍結することのないようにあらかじめ定められた冷媒蒸発温度（以下、第１設定温度ともいう）以上になるように圧縮機２１の回転数を制御する圧縮機フロスト制御器、４３は蒸発温度検知器４１で検知された冷媒蒸発温度が、利用者等から要求された能力を供給するのに必要なあらかじめ定められた冷媒蒸発温度（以下、第２設定温度という）になるように圧縮機２１の回転数を制御する圧縮機能力制御器、４４は圧縮機フロスト制御器４２と圧縮機能力制御器４３の出力を蒸発温度検知器４１で検知された冷媒蒸発温度に応じて切り替えあるいは融合して圧縮機２１の回転数を操作する圧縮機回転数操作器である。
【００２７】
本冷凍サイクル装置の動作のうちＣＯ_２冷媒の流れについては以下の通りである。すなわち、図中において、実線の矢印はＣＯ_２冷媒の流れ方向を示している。圧縮機２１で圧縮されたＣＯ_２冷媒は高温高圧状態となり放熱器２２へ導入される。放熱器２２では、ＣＯ_２冷媒は超臨界状態であるので、気液二相状態とはならずに空気や水などの外部流体に放熱する。その後、ＣＯ_２冷媒は、内部熱交換器２３の高圧側流路２３ｂにおいてさらに冷却される。さらに、減圧器２４では減圧されて低圧の気液二相状態となり吸熱器２５へ導入される。吸熱器２５では、空気や水などの外部流体を冷却しＣＯ_２冷媒は吸熱する。その後、内部熱交換器２３の低圧側流路２３ａにおいてガス状態となり、再び圧縮機２１に吸入される。このようなサイクルを繰り返すことにより、放熱器２２で放熱による加熱作用、例えば、暖房や水加熱、吸熱器２５で吸熱による冷却作用、例えば、冷房や除湿を行うことができる。
【００２８】
本冷凍サイクル装置は、ＣＯ_２冷媒を用いていることと、圧縮機２１を密閉容器内を冷凍サイクルにおける高圧側圧力と略同圧力とした圧縮機とした場合、従来用いられてきたフロン類を冷媒として用いた場合や、密閉容器内を冷凍サイクルにおける低圧側圧力と略同圧力とした圧縮機を用いた場合に比べて、圧縮機２１の電動要素の雰囲気温度が上昇して、圧縮機２１の電動要素の絶縁材料が変質し、圧縮機の信頼性を低下させるといった問題が生じる恐れがある。
【００２９】
しかし、本実施の形態においては、圧縮機回転数操作器４４によって圧縮機２１が適切に操作され、減圧器開度操作器３７によって減圧器２４が適切に操作されることから、上記のような問題の発生を未然に防止することができる。図３は圧縮機回転数操作器４４による圧縮機２１の動作と、減圧器開度操作器３７による減圧器２４の動作を示すフローチャートである。以下、このフローチャートを用いて説明する。
【００３０】
まず、圧縮機２１の動作について説明する。蒸発温度検知器４１で検知された冷媒蒸発温度と第１蒸発温度閾値Ｔｅ１（例えば吸熱器２５が凍結する冷媒蒸発温度をもとに設定）との比較を行い（ステップ２０１）、冷媒蒸発温度が第１蒸発温度閾値Ｔｅ１よりも低い場合には蒸発温度メンバシップ値を０に設定し（ステップ２０２）、冷媒蒸発温度が第１蒸発温度閾値Ｔｅ１より高い場合には第１蒸発温度閾値Ｔｅ１より高い第２蒸発温度閾値Ｔｅ２（例えば吸熱器２５が凍結する冷媒蒸発温度より若干高い温度に設定）との比較を行い（ステップ２０３）、冷媒蒸発温度が第２蒸発温度閾値Ｔｅ２よりも低い場合には温度に応じて０から１までの範囲で単調で連続した変化をする蒸発温度メンバシップ値を設定し（ステップ２０４）、冷媒蒸発温度が第２蒸発温度閾値Ｔｅ２より高い場合には蒸発温度メンバシップ値を１に設定する（ステップ２０５）。なお、第１蒸発温度閾値は、第１設定温度と同じ温度を設定してもよいが、これにこだわる必要はなく、例えば、第１設定温度より、若干低めの温度を設定してもよい。また、第２蒸発温度閾値についても、第１蒸発温度閾値より若干高く、第１設定温度より、若干低い温度を設定してもよい。
【００３１】
それから、圧縮機能力制御器４３による圧縮機２１の回転数と蒸発温度メンバシップ値との積量と、圧縮機フロスト制御器４２による圧縮機２１の回転数と１から蒸発温度メンバシップ値を減じた値との積量の和として圧縮機回転数を決定して圧縮機２１を操作する（ステップ２０６）。ここで、圧縮機能力制御器４３は、蒸発温度検知器４１で検知された冷媒蒸発温度が、利用者等から要求された能力を供給するのに必要なあらかじめ定められた冷媒蒸発温度（第２設定温度）となるように、圧縮機２１の回転数を決定するものである（図３中では能力制御という）。一方、圧縮機フロスト制御器４２は、蒸発温度検知器４１で検知された冷媒蒸発温度が、吸熱器２５が凍結することのないようにあらかじめ定められた冷媒蒸発温度（第１設定温度）以上になるように、圧縮機２１の回転数を決定するものである（図３中ではフロスト防止制御という）。
【００３２】
すなわち、蒸発温度検知器４１で検知される冷媒蒸発温度がステップ２０１で第１蒸発温度閾値Ｔｅ１より低いと判断されたときは、冷媒蒸発温度が低く吸熱器２５が凍結してしまう恐れがあることから、ステップ２０６では圧縮機フロスト制御器４２による圧縮機回転数を最優先にして、圧縮機２１の回転数を低下させて冷媒蒸発温度を上昇させる。また蒸発温度検知器４１で検知される冷媒蒸発温度がステップ２０１で第１蒸発温度閾値Ｔｅ１より高いと判断され、かつ、ステップ２０３で第２蒸発温度閾値Ｔｅ２より高いと判断されたときには、冷媒蒸発温度は吸熱器２５が凍結してしまう恐れのない状態であることから、ステップ２０６では圧縮機能力制御器４３による圧縮機回転数を最優先にして、利用者等から要求された能力を供給するのに必要なあらかじめ定められた冷媒蒸発温度（第２設定温度）となるように、圧縮機回転数を決定する。この時、蒸発温度検知器４１で検知された冷媒蒸発温度が第２設定温度よりも高いときには、能力が不足していると判断し圧縮機能力制御器４３により圧縮機回転数を増加方向に決定し、冷媒循環量を増大させる。逆に蒸発温度検知器４１で検知された冷媒蒸発温度が第２設定温度よりも低いときには、能力が過剰であると判断し圧縮機能力制御器４３により圧縮機回転数を減少方向に決定し、冷媒循環量を減少させる。また蒸発温度検知器４１で検知された冷媒蒸発温度がステップ２０１で第１蒸発温度閾値Ｔｅ１より高いと判断され、かつ、ステップ２０３で第２蒸発温度閾値Ｔｅ２より低いと判断されたときには、冷媒蒸発温度が低く、吸熱器２５がすぐに凍結してしまう恐れはないが、あまり好ましくない状態であるので、ステップ２０６では圧縮機フロスト制御器４２による圧縮機回転数と圧縮機能力制御器４３による圧縮機回転数とを混合して圧縮機２１を操作することから、吸熱器２５の凍結を防止しつつ、利用者等から要求された能力に応じた冷媒蒸発温度となるような運転が実現できる。
【００３３】
次に、減圧器２４の動作について説明する。吐出温度検知器３１で検知された冷媒吐出温度と第１吐出温度閾値Ｔｄ１（例えば圧縮機２１の許容使用範囲上限をもとに設定）との比較を行い（ステップ３０１）、冷媒吐出温度が第１吐出温度閾値Ｔｄ１よりも高い場合には吐出温度メンバシップ値を０に設定し（ステップ３０２）、冷媒吐出温度が第１吐出温度閾値Ｔｄ１より低い場合には第１吐出温度閾値Ｔｄ１より低い第２吐出温度閾値Ｔｄ２（例えば圧縮機２１の常用使用範囲上限をもとに設定）との比較を行い（ステップ３０３）、冷媒吐出温度が第２吐出温度閾値Ｔｄ２よりも高い場合には冷媒吐出温度に応じて０から１までの範囲で単調で連続した変化をする吐出温度メンバシップ値を設定し（ステップ３０４）、冷媒吐出温度が第２吐出温度閾値Ｔｄ２より低い場合には吐出温度メンバシップ値を１に設定する（ステップ３０５）。
【００３４】
それから、減圧器最適高圧制御器３６による減圧器２４の開度と吐出温度メンバシップ値との積量と、減圧器吐出温度制御器３２による減圧器２４の開度と１から吐出温度メンバシップ値を減じた値との積量の和として減圧器２４の開度を決定して減圧器２４の開度を操作する（ステップ３０６）。ここで、減圧器最適高圧制御器３６は、高圧検知器３５で検知された高圧側圧力が、出口温度検知器３３で検知された冷媒出口温度に基づいて最適高圧演算器３４で演算された最適高圧よりも高ければ減圧器２４の開度を増加方向に、低ければ減圧器２４の開度を減少方向に減圧器２４の開度を決定するものである（図３中では最適高圧制御という）。一方、減圧器吐出温度制御器３２は、吐出温度検知器３１で検知された冷媒吐出温度が、あらかじめ定められた冷媒吐出温度より高ければ減圧器２４の開度を増加方向に、低ければ減圧器２４の開度を減少方向に減圧器２４の開度を決定するものである（図３中では吐出温度制御という）。
【００３５】
すなわち、吐出温度検知器３１で検知される冷媒吐出温度がステップ３０１で第１吐出温度閾値Ｔｄ１より高いと判断されたときは、冷媒吐出温度が圧縮機２１の許容使用範囲をはずれており圧縮機２１の信頼性を著しく損なう状態であることから、ステップ３０６では減圧器吐出温度制御器３２による減圧器開度を最優先にして、減圧器２４の開度を増加させて冷媒吐出温度を低下させる。また吐出温度検知器３１で検知される冷媒吐出温度がステップ３０１で第１吐出温度閾値Ｔｄ１より低いと判断され、かつ、ステップ３０３で第２吐出温度閾値Ｔｄ２より低いと判断されたときには、冷媒吐出温度は圧縮機２１の常用使用範囲内であり圧縮機２１の信頼性には問題ない状態であることから、ステップ３０６では減圧器最適高圧制御器３６による減圧器開度を最優先にして減圧器開度を決定する。この時、高圧検知器３５で検知された冷凍サイクルにおける高圧側圧力が、出口温度検知器３３で検知された冷媒出口温度に基づいて、最適高圧演算器３４により演算された最適高圧よりも高いときには減圧器最適高圧制御器３６により減圧器２４の開度を増加方向に決定する。この結果、高圧側（圧縮機２１吐出〜放熱器２２〜内部熱交換器の高圧側流路２３ｂ〜減圧器２４入口）の冷媒が低圧側（減圧器２４出口〜吸熱器２５〜内部熱交換器の低圧側流路２３ａ〜圧縮機２１吸入）へ移動して高圧側圧力が低下するので、高圧側圧力を最適高圧に一致させることができ、ＣＯＰの高い状態での運転が実現できる。逆に高圧検知器３５で検知された高圧側圧力が最適高圧演算器３４により演算された最適高圧よりも低いときには、減圧器最適高圧制御器３６により減圧器２４の開度を減少方向に決定する。この結果、低圧側の冷媒が高圧側へ移動して高圧側圧力が上昇するので、高圧側圧力を最適高圧に一致させることができ、ＣＯＰの高い状態での運転が実現できる。また吐出温度検知器３１で検知される冷媒吐出温度がステップ３０１で第１吐出温度閾値Ｔｄ１より低いと判断され、かつ、ステップ３０３で第２吐出温度閾値Ｔｄ２より高いと判断されたときには、冷媒吐出温度は圧縮機２１の使用許容範囲内ではあるが常用使用範囲外であり圧縮機２１の信頼性の面からはあまり好ましくない状態であるので、ステップ３０６では減圧器吐出温度制御器３２による減圧器２４の開度と減圧器最適高圧制御器３６による減圧器２４の開度とを混合して減圧器２４を操作することから、冷媒吐出温度を圧縮機２１の常用使用範囲内に収めつつ、高圧側圧力を最適高圧に一致させることができ、ＣＯＰの高い状態での運転が実現できる。
【００３６】
以上のような操作を一定時間間隔で繰り返し行うことで、ＣＯ_２冷媒を用い、圧縮機２１が密閉容器内を冷凍サイクルにおける高圧側圧力と略同圧力とした圧縮機であっても、圧縮機能力制御器４３による能力制御と圧縮機フロスト制御器４２によるフロスト防止制御を圧縮機回転数操作器４４が切り替えあるいは融合することで吸熱器２５の凍結を防止しつつ、利用者等から要求された能力に応じた冷凍サイクル装置の運転が実現でき、かつ、減圧器最適高圧制御器３６による最適高圧制御と減圧器吐出温度制御器３２による吐出温度制御を減圧器開度操作器３７が切り替えあるいは融合することで、圧縮機２１の電動要素の絶縁材料が変質するほど、圧縮機２１の冷媒吐出温度が上昇するのを防止しながら、冷凍サイクル装置を効率の高い状態での運転が実現できる。
【００３７】
なお、吸熱器２５が水冷式などの熱交換器であって、吸熱器２５が凍結する恐れがない場合などでは、圧縮機フロスト制御器４２を省略し、上記説明した操作から圧縮機フロスト制御器４２にまつわる部分を省略することも可能である。さらに、吐出温度検知器３１、出口温度検知器３３、蒸発温度検知器４１による冷媒吐出温度、冷媒出口温度、冷媒蒸発温度の検知は、圧縮機２１や放熱器２２や吸熱器２５の温度を直接測定することで検知しても良いし、圧縮機２１や放熱器２２や吸熱器２５の周囲温度を測定して間接的に検知しても良い。また、高圧検知器３５についても、直接圧力を検知しても良いし、冷凍サイクルの状態の一部を検知して推定するようにしても良い。最適高圧演算器３４も、出口温度検知器３３が検知した温度により最適高圧を算出すると説明しているが、冷凍サイクルの状態の少なくとも一つを検知して最適高圧を算出するようにしても良い。また、本実施の形態では圧縮機２１の操作による冷媒循環量の変更を、圧縮機２１の回転数で行うものとして説明したが、圧縮機２１により冷媒循環量を変更する他の手段、例えば、往復型圧縮機のピストンのストローク量の増減などで行っても良い。
【００３８】
また、二酸化炭素を冷媒として用い、少なくとも、圧縮機、放熱器、減圧器、吸熱器を接続した冷凍サイクル装置において、前記吸熱器出口から前記圧縮機吸入までのいずれかの位置での冷媒過熱度を演算する過熱度演算器と、前記過熱度演算器が演算した冷媒過熱度に応じて前記減圧器の開度を操作し冷媒過熱度を調整する減圧器過熱度制御器と、前記放熱器の冷媒出口温度を検知する出口温度検知器と、前記出口温度検知器が検知した冷媒出口温度に応じて前記減圧器の開度を操作し高圧を調整する減圧器最適高圧制御器と、前記過熱度演算器が演算した冷媒過熱度に応じて前記減圧器過熱度制御器と前記減圧器最適高圧制御器とを切り替えて前記減圧器の開度を操作する減圧器開度操作器と、前記吸熱器の冷媒蒸発温度を検知する蒸発温度検知器と、前記蒸発温度検知器が検知した冷媒蒸発温度に応じて前記圧縮機の回転数を操作し能力を調整する圧縮機能力制御器とを備えたことを特徴とする冷凍サイクル装置における圧縮機として、本発明の圧縮機を用いてもよい。この冷凍サイクル装置は、減圧器過熱度制御器、減圧器最適高圧制御器、減圧器開度操作器、圧縮機能力制御器によって減圧器と圧縮機を適正に制御することで、利用者等から要求された能力に応じ、かつ、効率の高い状態で運転を維持しながら、圧縮機の電動要素の絶縁材料が変質するほどに圧縮機の冷媒吐出温度が上昇することを防止した運転が実現できるものであり、このような冷凍サイクル装置に本発明の圧縮機を用いれば、導電要素の絶縁材料の変質による信頼性の低下は、より確実に阻止できる（以下、この冷凍サイクル装置を実施の形態Ｂと位置付ける）。
【００３９】
図４は、この冷凍サイクル装置の概略を示す構成図である。図４においては、図２と同じ構成要素については同一の符号を付し、説明を省略する。図４において、５１は吸熱器２５出口での冷媒過熱度を演算する過熱度演算器（なお、冷媒過熱度は吸熱器２５出口の冷媒温度と冷媒蒸発温度の差であり、検知した吸熱器２５出口の温度から蒸発温度検知器４１で検知した温度を引いて冷媒過熱度を演算すると良い。）、５２は過熱度演算器５１で演算された冷媒過熱度が設定値となるように減圧器２４の開度を制御する減圧器過熱度制御器、５３は減圧器過熱度制御器５２と減圧器最適高圧制御器３６の出力を過熱度演算器５１で演算された冷媒過熱度に応じて切り替えあるいは融合して減圧器２４の開度を操作する減圧器開度操作器である。
【００４０】
本冷凍サイクル装置は、ＣＯ_２冷媒を用いていることと、圧縮機２１を密閉容器内を冷凍サイクルにおける高圧側圧力と略同圧力とした圧縮機とした場合、従来用いられてきたフロン類を冷媒として用いた場合や、密閉容器内を冷凍サイクルにおける低圧側圧力と略同圧力とした圧縮機を用いた場合に比べて、圧縮機２１の電動要素の雰囲気温度が上昇して、圧縮機２１の電動要素の絶縁材料が変質し、圧縮機の信頼性を低下させるといった問題が生じる恐れがある。
【００４１】
しかし、本実施の形態においては、圧縮機回転数操作器４４によって圧縮機２１が適切に操作され、減圧器開度操作器５３によって減圧器２４が適切に操作されることから、上記のような問題の発生を未然に防止することができる。図５は圧縮機回転数操作器４４による圧縮機２１の動作と、減圧器開度操作器５３による減圧器２４の動作を示すフローチャートである。以下、このフローチャートを用いて説明する。
【００４２】
圧縮機２１の動作については（実施の形態Ａ）と同様であるため、説明を省略する。
次に、減圧器２４の動作について説明する。過熱度演算器５１で演算された冷媒過熱度と第１過熱度閾値ＳＨ１（例えば圧縮機２１の冷媒吐出温度が許容使用範囲上限となる冷媒過熱度をもとに設定）との比較を行い（ステップ４０１）、冷媒過熱度が第１過熱度閾値ＳＨ１よりも大きい場合には過熱度メンバシップ値を０に設定し（ステップ４０２）、冷媒過熱度が第１過熱度閾値ＳＨ１より小さい場合には第１過熱度閾値ＳＨ１より小さい第２過熱度閾値ＳＨ２（例えば圧縮機２１の冷媒吐出温度が常用使用範囲上限となる冷媒過熱度をもとに設定）との比較を行い（ステップ４０３）、冷媒過熱度が第２過熱度閾値ＳＨ２よりも大きい場合には冷媒過熱度に応じて０から１までの範囲で単調で連続した変化をする過熱度メンバシップ値を設定し（ステップ４０４）、冷媒過熱度が第２過熱度閾値ＳＨ２より小さい場合には過熱度メンバシップ値を１に設定する（ステップ４０５）。
【００４３】
それから、減圧器最適高圧制御器３６による減圧器２４の開度と過熱度メンバシップ値との積量と、減圧器過熱度制御器５２による減圧器２４の開度と１から過熱度メンバシップ値を減じた値との積量の和として減圧器２４の開度を決定して減圧器２４の開度を操作する（ステップ４０６）。ここで、減圧器最適高圧制御器３６は、高圧検知器３５で検知された高圧側圧力が、出口温度検知器３３で検知された冷媒出口温度に基づいて最適高圧演算器３４で演算された最適高圧よりも高ければ減圧器２４の開度を増加方向に、低ければ減圧器２４の開度を減少方向に減圧器２４の開度を決定するものである（図５中では最適高圧制御という）。一方、減圧器過熱度制御器５２は、過熱度演算器５１で演算された過熱度が、あらかじめ定められた過熱度より大きければ減圧器２４の開度を増加方向に、小さければ減圧器２４の開度を減少方向に減圧器２４の開度を決定するものである（図５中では過熱度制御という）。
【００４４】
すなわち、過熱度演算器５１で演算される冷媒過熱度がステップ４０１で第１過熱度閾値ＳＨ１より大きいと判断されたときは、冷媒過熱度が大きいために圧縮機２１の冷媒吐出温度が許容使用範囲をはずれており圧縮機２１の信頼性を著しく損なう状態であることから、ステップ４０６では減圧器過熱度制御器５２による減圧器開度を最優先にして、減圧器２４の開度を増加させて冷媒過熱度を小さくすることにより冷媒吐出温度を低下させる。また過熱度演算器５１で演算される冷媒過熱度がステップ４０１で第１過熱度閾値ＳＨ１より小さいと判断され、かつ、ステップ４０３で第２過熱度閾値ＳＨ２より小さいと判断されたときには、冷媒過熱度は適正値であり圧縮機２１の冷媒吐出温度は圧縮機２１の常用使用範囲内であり信頼性には問題ない状態であることから、ステップ４０６では減圧器最適高圧制御器３６による減圧器開度を最優先にして減圧器開度を決定する。この時、高圧検知器３５で検知された冷凍サイクルにおける高圧側圧力が、出口温度検知器３３で検知された冷媒出口温度に基づいて、最適高圧演算器３４により演算された最適高圧よりも高いときには減圧器最適高圧制御器３６により減圧器２４の開度を増加方向に決定する。この結果、高圧側の冷媒が低圧側へ移動して高圧側圧力が低下するので、高圧側圧力を最適高圧に一致させることができ、ＣＯＰの高い状態での運転が実現できる。逆に高圧検知器３５で検知された高圧側圧力が最適高圧演算器３４により演算された最適高圧よりも低いときには、減圧器最適高圧制御器３６により減圧器２４の開度を減少方向に決定する。この結果、低圧側の冷媒が高圧側へ移動して高圧側圧力が上昇するので、高圧側圧力を最適高圧に一致させることができ、ＣＯＰの高い状態での運転が実現できる。また過熱度演算器５１で演算される冷媒過熱度がステップ４０１で第１過熱度閾値ＳＨ１より小さいと判断され、かつ、ステップ４０３で第２過熱度閾値ＳＨ２より大きいと判断されたときには、圧縮機２１の冷媒吐出温度が圧縮機２１の使用許容範囲内ではあるが常用使用範囲外となり圧縮機２１の信頼性の面からはあまり好ましくない状態となる冷媒過熱度であるので、ステップ４０６では減圧器過熱度制御器５２による減圧器２４の開度と減圧器最適高圧制御器３６による減圧器２４の開度とを混合して減圧器２４を操作することから、冷媒吐出温度が圧縮機２１の常用使用範囲内となる冷媒過熱度を保ちつつ、高圧側圧力を最適高圧に一致させることができ、ＣＯＰの高い状態での運転が実現できる。
【００４５】
以上のような操作を一定時間間隔で繰り返し行うことで、ＣＯ_２冷媒を用い、圧縮機２１が密閉容器内を冷凍サイクルにおける高圧側圧力と略同圧力とした圧縮機であっても、圧縮機能力制御器４３による能力制御と圧縮機フロスト制御器４２によるフロスト防止制御を圧縮機回転数操作器４４が切り替えあるいは融合することで吸熱器２５の凍結を防止しつつ、利用者等から要求された能力に応じた冷凍サイクル装置の運転が実現でき、かつ、減圧器最適高圧制御器３６による最適高圧制御と減圧器過熱度制御器５２による過熱度制御を減圧器開度操作器５３が切り替えあるいは融合することで、圧縮機２１の電動要素の絶縁材料が変質するほど、圧縮機２１の冷媒吐出温度が上昇するのを防止しながら、冷凍サイクル装置を効率の高い状態での運転が実現できる。
【００４６】
なお、本実施の形態では過熱度演算器５１は、吸熱器２５出口〜内部熱交換器の低圧側流路２３ａ入口での冷媒過熱度を演算するものとして説明したが、内部熱交換器の低圧側流路内や、内部熱交換器の低圧側流路２３ａ出口〜圧縮機２１吸入での冷媒過熱度を演算してもよい。
【００４７】
また、二酸化炭素を冷媒として用い、少なくとも、圧縮機、放熱器、減圧器、吸熱器を接続した冷凍サイクル装置において、前記吸熱器出口から前記圧縮機吸入までのいずれかの位置での冷媒乾き度を演算する乾き度演算器と、前記乾き度演算器が演算した冷媒乾き度に応じて前記減圧器の開度を操作し冷媒乾き度を調整する減圧器乾き度制御器と、前記放熱器の冷媒出口温度を検知する出口温度検知器と、前記出口温度検知器が検知した冷媒出口温度に応じて前記減圧器の開度を操作し高圧を調整する減圧器最適高圧制御器と、前記乾き度演算器が演算した冷媒乾き度に応じて前記減圧器乾き度制御器と前記減圧器最適高圧制御器とを切り替えて前記減圧器の開度を操作する減圧器開度操作器と、前記吸熱器の冷媒蒸発温度を検知する蒸発温度検知器と、前記蒸発温度検知器が検知した冷媒蒸発温度に応じて前記圧縮機の回転数を操作し能力を調整する圧縮機能力制御器とを備えたことを特徴とする冷凍サイクル装置における圧縮機として、本発明の圧縮機を用いてもよい。この冷凍サイクル装置は、減圧器乾き度制御器、減圧器最適高圧制御器、減圧器開度操作器、圧縮機能力制御器によって減圧器と圧縮機を適正に制御することで、利用者等から要求された能力に応じ、かつ、効率の高い状態で運転を維持しながら、圧縮機の電動要素の絶縁材料が変質するほどに圧縮機の冷媒吐出温度が上昇することを防止した運転が実現できるものであり、このような冷凍サイクル装置に本発明の圧縮機を用いれば、導電要素の絶縁材料の変質による信頼性の低下は、より確実に阻止できる（以下、この冷凍サイクル装置を実施の形態Ｃと位置付ける）。
【００４８】
図６は、この冷凍サイクル装置の概略を示す構成図であり、図４と同じ構成要素については同一の符号を付すか図から省略し、説明を省略する。図６において、６１は吸熱器２５出口での冷媒乾き度を演算する乾き度演算器、６２は乾き度演算器６１で演算された冷媒乾き度が設定値となるように減圧器２４の開度を制御する減圧器乾き度制御器、６３は減圧器乾き度制御器６２と減圧器最適高圧制御器３６の出力を乾き度演算器６１で演算された冷媒乾き度に応じて切り替えあるいは融合して減圧器２４の開度を操作する減圧器開度操作器である。乾き度演算器６１は、吐出温度検知器３１が検知した冷媒吐出温度、高圧検知器３５が検知した冷凍サイクルにおける高圧側圧力、蒸発温度検知器４１が検知した冷媒蒸発温度をもとに、冷媒乾き度を演算する。すなわち、図７に示すモリエル線図から、吐出温度検知器３１が検知した冷媒吐出温度Ｔｄと高圧検知器３５が検知した高圧側圧力Ｐｈから、点１が求められ、さらに、あらかじめ定められた圧縮機の効率を考慮したエントロピの傾きｓの点１を通る直線と、蒸発温度検知器４１が検知した冷媒蒸発温度Ｔｅを飽和温度として演算して求めた低圧側圧力Ｐｅとの交点により、点２が求められる。求められた点２のエンタルピと、冷媒蒸発温度Ｔｅ、あるいは、低圧側圧力Ｐｅから演算できる点Ｌおよび点Ｖのエンタルピの関係から乾き度を求めるとよい。
【００４９】
図８は圧縮機回転数操作器４４による圧縮機２１の動作と、減圧器開度操作器６３による減圧器２４の動作を示すフローチャートである。以下、このフローチャートを用いて説明する。
【００５０】
圧縮機２１の動作については（実施の形態Ａ）や（実施の形態Ｂ）と同様であるため、説明を省略する。
次に、減圧器２４の動作について説明する。乾き度演算器６１で演算された冷媒乾き度と第１乾き度閾値χ１（例えば圧縮機２１の冷媒吐出温度が許容使用範囲上限となる冷媒乾き度をもとに設定）との比較を行い（ステップ５０１）、冷媒乾き度が第１乾き度閾値χ１よりも大きい場合には乾き度メンバシップ値を０に設定し（ステップ５０２）、冷媒乾き度が第１乾き度閾値χ１より小さい場合には第１乾き度閾値χ１より小さい第２乾き度閾値χ２（例えば圧縮機２１の冷媒吐出温度が常用使用範囲上限となる冷媒乾き度をもとに設定）との比較を行い（ステップ５０３）、冷媒乾き度が第２乾き度閾値χ２よりも大きい場合には冷媒乾き度に応じて０から１までの範囲で単調で連続した変化をする乾き度メンバシップ値を設定し（ステップ５０４）、冷媒乾き度が第２乾き度閾値χ２より小さい場合には乾き度メンバシップ値を１に設定する（ステップ５０５）。
【００５１】
それから、減圧器最適高圧制御器３６による減圧器２４の開度と乾き度メンバシップ値との積量と、減圧器乾き度制御器６２による減圧器２４の開度と１から乾き度メンバシップ値を減じた値との積量の和として減圧器２４の開度を決定して減圧器２４の開度を操作する（ステップ５０６）。ここで、減圧器最適高圧制御器３６は、高圧検知器３５で検知された高圧側圧力が、出口温度検知器３３で検知された冷媒出口温度に基づいて最適高圧演算器３４で演算された最適高圧よりも高ければ減圧器２４の開度を増加方向に、低ければ減圧器２４の開度を減少方向に減圧器２４の開度を決定するものである（図８中では最適高圧制御という）。一方、減圧器乾き度制御器６２は、乾き度演算器６１で演算された乾き度が、あらかじめ定められた乾き度より大きければ減圧器２４の開度を増加方向に、小さければ減圧器２４の開度を減少方向に減圧器２４の開度を決定するものである（図８中では乾き度制御という）。
【００５２】
すなわち、乾き度演算器６１で演算される冷媒乾き度がステップ５０１で第１乾き度閾値χ１より大きいと判断されたときは、冷媒乾き度が大きいために圧縮機２１の冷媒吐出温度が許容使用範囲をはずれており圧縮機２１の信頼性を著しく損なう状態であることから、ステップ５０６では減圧器乾き度制御器６２による減圧器開度を最優先にして、減圧器２４の開度を増加させて冷媒乾き度を小さくすることにより冷媒吐出温度を低下させる。また乾き度演算器６１で演算される冷媒乾き度がステップ５０１で第１乾き度閾値χ１より小さいと判断され、かつ、ステップ５０３で第２乾き度閾値χ２より小さいと判断されたときには、冷媒乾き度は適正値であり圧縮機２１の冷媒吐出温度は圧縮機２１の常用使用範囲内であり信頼性には問題ない状態であることから、ステップ５０６では減圧器最適高圧制御器３６による減圧器開度を最優先にして減圧器開度を決定する。この時、高圧検知器３５で検知された冷凍サイクルにおける高圧側圧力が、出口温度検知器３３で検知された冷媒出口温度に基づいて、最適高圧演算器３４により演算された最適高圧よりも高いときには減圧器最適高圧制御器３６により減圧器２４の開度を増加方向に決定する。この結果、高圧側の冷媒が低圧側へ移動して高圧側圧力が低下するので、高圧側圧力を最適高圧に一致させることができ、ＣＯＰの高い状態での運転が実現できる。逆に高圧検知器３５で検知された高圧側圧力が最適高圧演算器３４により演算された最適高圧よりも低いときには、減圧器最適高圧制御器３６により減圧器２４の開度を減少方向に決定する。この結果、低圧側の冷媒が高圧側へ移動して高圧側圧力が上昇するので、高圧側圧力を最適高圧に一致させることができ、ＣＯＰの高い状態での運転が実現できる。また乾き度演算器６１で演算される冷媒乾き度がステップ５０１で第１乾き度閾値χ１より小さいと判断され、かつ、ステップ５０３で第２乾き度閾値χ２より大きいと判断されたときには、圧縮機２１の冷媒吐出温度が圧縮機２１の使用許容範囲内ではあるが常用使用範囲外となり圧縮機２１の信頼性の面からはあまり好ましくない状態となる冷媒乾き度であるので、ステップ５０６では減圧器乾き度制御器６２による減圧器２４の開度と減圧器最適高圧制御器３６による減圧器２４の開度とを混合して減圧器２４を操作することから、冷媒吐出温度が圧縮機２１の常用使用範囲内となる冷媒乾き度を保ちつつ、高圧側圧力を最適高圧に一致させることができ、ＣＯＰの高い状態での運転が実現できる。
【００５３】
すなわち、本実施の形態においては、（実施の形態Ａ）や（実施の形態Ｂ）と同様に、減圧器開度操作器６３によって減圧器２４が適切に操作されるために、ＣＯ_２冷媒を用い、圧縮機２１が密閉容器内を冷凍サイクルにおける高圧側圧力と略同圧力とした圧縮機であっても、圧縮機能力制御器４３による能力制御と圧縮機フロスト制御器４２によるフロスト防止制御を圧縮機回転数操作器４４が切り替えあるいは融合することで吸熱器２５の凍結を防止しつつ、利用者等から要求された能力に応じた冷凍サイクル装置の運転が実現でき、かつ、減圧器最適高圧制御器３６による最適高圧制御と減圧器乾き度制御器６２による乾き度制御を減圧器開度操作器６３が切り替えあるいは融合することで、圧縮機２１の電動要素の絶縁材料が変質するほど、圧縮機２１の冷媒吐出温度が上昇するのを防止しながら、冷凍サイクル装置を効率の高い状態での運転が実現できる。
【００５４】
（実施の形態Ｂ）のような構成の冷凍サイクル装置と（実施の形態Ｃ）のような構成の冷凍サイクル装置で評価を行い、図９（ａ）に示すような吸熱器２５出口の冷媒過熱度または冷媒乾き度と圧縮機２１の冷媒吐出温度の関係を得た。図９（ａ）の縦軸は冷媒過熱度が０Ｋでの冷媒吐出温度を基準にした差であり、横軸は冷媒過熱度が０Ｋでの吸入エンタルピを基準にした差の軸に、冷媒過熱度と冷媒乾き度の軸を併せて表示している。図９（ａ）より冷媒過熱度を０Ｋ以上（すなわち冷媒乾き度１．０以上）の領域では、冷媒乾き度１．０以下（すなわち冷媒過熱度０Ｋ以下）の領域より、吸入エンタルピの増加に対する冷媒吐出温度の上昇が大きいことがわかる。すなわち、冷媒吐出温度の上昇を低減し、圧縮機２１の電動要素の絶縁材料が変質するのを防止するには、吸熱器２５出口の冷媒過熱度を０Ｋ以下、すなわち、冷媒乾き度を１．０以下となるように制御することが望ましい。次に、能力測定の結果を図９（ｂ）に示す。図９（ｂ）の縦軸は、冷媒過熱度が０Ｋでの能力を１００とした比である。図９（ｂ）より吸熱器２５出口における冷媒乾き度が０．８以下の場合には、吸熱器２５の入口と出口のエンタルピ差が減少するため、圧縮機能力制御器４３により圧縮機回転数を調整しているにも関わらず、能力が低下し冷凍サイクル装置として十分に機能しないことがわかる。したがって、これら両方の特性を考慮すると、冷媒乾き度を０．８以上１．０以下となるように制御することが望ましい。
【００５５】
【発明の効果】
以上述べたところから明らかなように、本発明によれば、二酸化炭素を冷媒として用い、少なくとも圧縮要素と電動要素とを密閉容器内に収納し、前記密閉容器内が冷凍サイクルにおける高圧側圧力と略同圧力である冷凍サイクル装置用圧縮機であっても、絶縁材料として耐熱性に優れたポリビニルホルマール、ポリフェニレンサルファイド、ポリエステルイミド、ポリアミド、ポリアミドイミド、ポリイミドのうちの少なくとも１つを使用し、かつ、鉱油系油、アルキルベンゼン油およびそれらの混合物から選ばれるいずれか一つを主成分とする冷凍機油を使用しているために、電動要素の雰囲気温度が上昇して絶縁材料が変質し、その結果、圧縮機の信頼性が低下してしまうといったことがなく、高効率な圧縮機を実現できる。
さらに、圧縮機に封入される冷凍機油に含まれる水分の重量含有率を１００重量ｐｐｍ以下、望ましくは５０重量ｐｐｍ以下とすると、絶縁材料が変質し圧縮機の信頼性が低下してしまうことをさらに防止できる。
ここで、吸湿性の小さい、鉱油系油、アルキルベンゼン油およびそれらの混合物から選ばれるいずれか一つを主成分とする冷凍機油を用いることで、冷凍機油に含まれる水分の重量含有率を１００重量ｐｐｍ以下、望ましくは５０重量ｐｐｍ以下とすることが水分管理上容易となる。
また、上記圧縮機を用いれば、圧縮機の信頼性を低下させることなく、かつ、ＣＯ_２冷媒とともに吐出される冷凍機油を低減できるために、吐出される冷凍機油によって、放熱器や吸熱器での熱伝達が阻害され、冷凍サイクル装置の性能を低下させることがない効率の高い冷凍サイクル装置を実現することができる。
【図面の簡単な説明】
【図１】本発明の冷凍サイクル装置用圧縮機の一例の概略を示す構成図
【図２】本発明の冷凍サイクル装置用圧縮機が好適に用いられる冷凍サイクル装置（実施の形態Ａ）の概略を示す構成図
【図３】この冷凍サイクル装置の動作を示すフローチャート
【図４】本発明の冷凍サイクル装置用圧縮機が好適に用いられる冷凍サイクル装置（実施の形態Ｂ）の概略を示す構成図
【図５】この冷凍サイクル装置の動作を示すフローチャート
【図６】本発明の冷凍サイクル装置用圧縮機が好適に用いられる冷凍サイクル装置（実施の形態Ｃ）の概略を示す構成図
【図７】冷媒過熱度または冷媒乾き度と冷媒吐出温度、高圧、低圧の関係を示すモリエル線図
【図８】この冷凍サイクル装置の動作を示すフローチャート
【図９】冷媒過熱度または冷媒乾き度と冷媒吐出温度の関係
【図１０】従来の冷凍サイクル装置の概略を示す構成図
【符号の説明】
１、２１　　圧縮機
２、２２　　放熱器
３、２３　　内部熱交換器
４、２４　　減圧器
５、２５　　吸熱器
１０　　　　密閉容器
１１　　　　圧縮要素
１１０　　　圧縮室
１１１　　　吐出孔
１２　　　　吸入管
１３　　　　電動要素
１３１　　　ステータ
１３２　　　ロータ
１４　　　　冷凍機油
１５　　　　駆動軸
１５０　　　冷凍機油経路
１５１　　　ポンプ
１６　　　　コア
１７　　　　マグネットワイヤ
１８　　　　絶縁フィルム
１９　　　　吐出管
３１　　　　吐出温度検知器
３２　　　　減圧器吐出温度制御器
３３　　　　出口温度検知器
３４　　　　最適高圧演算器
３５　　　　高圧検知器
３６　　　　減圧器最適高圧制御器
３７、５３、６３　減圧器開度操作器
４１　　　　蒸発温度検知器
４２　　　　圧縮機フロスト制御器
４３　　　　圧縮機能力制御器
４４　　　　圧縮機回転数操作器
５１　　　　過熱度演算器
５２　　　　減圧器過熱度制御器
６１　　　　乾き度演算器
６２　　　　減圧器乾き度制御器[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a compressor for a refrigeration cycle device using carbon dioxide as a refrigerant and a refrigeration cycle device.
[0002]
[Prior art]
Air conditioners, car air conditioners, water heaters, etc. use a refrigeration cycle device that connects a compressor, a radiator, a decompressor, a heat absorber, etc. For these, hydrocarbons containing fluorine atoms (fluorocarbons) have been used. However, fluorocarbons are not necessarily satisfactory refrigerants because they have the property of destroying the ozone layer, and have a long greenhouse effect in the atmosphere, which has a large greenhouse effect and affects global warming. .
[0003]
Therefore, instead of CFCs, carbon dioxide (hereinafter referred to as CO2) has an ozone depletion potential of zero and a significantly lower global warming potential than CFCs. ₂ The possibility of a refrigeration cycle device using ethane or the like as a refrigerant is being studied. For example, Japanese Patent No. ₂ A refrigeration cycle device using a refrigerant is disclosed.
[0004]
The outline of the configuration of the refrigeration cycle apparatus disclosed in Japanese Patent No. 2132329 will be described with reference to FIG. The refrigeration cycle apparatus of FIG. ₂ Basic components including a compressor 1, a radiator 2, an internal heat exchanger 3, a pressure reducer 4, and a heat absorber 5 configured to exchange heat between a low pressure side flow path 3a and a high pressure side flow path 3b using a refrigerant. And The low pressure side flow path 3a of the internal heat exchanger 3 is configured so that the refrigerant flows between the heat sink 5 and the suction of the compressor 1, and the high pressure side flow path 3b is connected between the radiator 2 and the pressure reducer 4. Is configured to flow.
[0005]
The operation of the refrigeration cycle device will be described. In the drawings, solid arrows indicate the flow direction of the refrigerant. CO compressed by compressor 1 ₂ The refrigerant enters a high-temperature and high-pressure state and is introduced into the radiator 2. In the radiator 2, CO ₂ Since the refrigerant is in a supercritical state, the refrigerant radiates heat to an external fluid such as air or water without being in a gas-liquid two-phase state. Then, CO ₂ The refrigerant is further cooled in the high-pressure side passage 3b of the internal heat exchanger 3. Further, the pressure is reduced in the pressure reducer 4 to be in a low-pressure gas-liquid two-phase state, and is introduced into the heat absorber 5. The heat absorber 5 cools an external fluid such as air or water to reduce CO 2 ₂ The refrigerant absorbs heat. Thereafter, the gas enters the gas state in the low-pressure side passage 3 a of the internal heat exchanger 3 and is sucked into the compressor 1 again. By repeating such a cycle, the radiator 2 can perform a heating action by heat radiation, for example, heating or water heating, and the heat absorber 5 can perform a cooling action by heat absorption, for example, cooling or dehumidification.
[0006]
Where CO ₂ It has been found that the refrigerant discharge temperature of the compressor 1 using the refrigerant is about 20K higher than fluorocarbons (HCFC22, R410A, R407C, etc.) which are conventionally used refrigerants. Therefore, as for the compressor 1 used in such a refrigeration cycle apparatus, for example, as disclosed in Japanese Patent Application Laid-Open No. 2000-97177, a low pressure in the refrigeration cycle Side pressure (outlet of pressure reducer 4-heat sink 5-low pressure side flow path 3a of internal heat exchanger-pressure of suction of compressor 1), and the insulating material of the electric element housed in the sealed container is frozen. It has been proposed to prevent deterioration due to a rise in temperature of machine oil or the like and to improve the reliability of the compressor.
[0007]
Insulating layers such as windings of electric elements of compressors using conventional refrigerants and insulating materials such as connection portions of electric wires, insulating films, tying yarns, etc., have refrigerant resistance characteristics, good workability, and easy supply. From the viewpoint of the quality, organic materials such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate are widely used.
[0008]
[Problems to be solved by the invention]
However, when polyalkylene glycol oil or polyol ester oil is used as a refrigerator oil, ₂ Assuming that the pressure in the closed vessel of the compressor 1 using the refrigerant is substantially the same as the low pressure side pressure in the refrigeration cycle, CO ₂ Since the refrigerant dissolves in these refrigerating machine oils in a larger amount than conventional refrigerants, the viscosity of the refrigerating machine oil decreases, and the amount of the refrigerating machine oil discharged to the outside of the closed container together with the refrigerant (hereinafter, the oil discharge amount) Increase). It has been clarified that the discharged refrigerating machine oil inhibits heat transfer in the radiator 2 and the heat absorber 5 and causes a new problem such as a decrease in performance of the refrigeration cycle device.
[0009]
As a means for solving such a problem that the oil discharge amount increases, as in the case of the conventional refrigerant, the inside of the closed vessel of the compressor 1 is set to the high pressure side pressure in the refrigeration cycle (compressor 1 discharge to radiator 2 to internal (The pressure at the high pressure side flow path 3b to the inlet of the pressure reducer 4) of the heat exchanger, and the compressor oil discharged together with the refrigerant from the compression element in the compressor 1 is discharged into the closed vessel once. It is conceivable to reduce the amount of oil discharged to the outside of the closed container of the compressor 1.
[0010]
However, the ambient temperature of the electric element of the compressor, in which the inside of the closed vessel is substantially the same as the high-pressure side pressure in the refrigeration cycle, is the same as the low-pressure side pressure in the refrigeration cycle, because the atmosphere of the compressor is a discharged refrigerant atmosphere. Since the temperature rises as compared with the compressor, the insulating material of the electric element sealed in the sealed container may be deteriorated, which may cause a problem that the reliability of the compressor is reduced. ₂ In the case of the refrigerant, as described above, the discharge temperature is higher than that of the conventional fluorocarbons, which may cause a serious problem.
[0011]
Therefore, the present invention solves the above-described problem by reducing CO2 ₂ An object of the present invention is to provide a compressor and a refrigeration cycle device that use a refrigerant and that are highly efficient while avoiding a decrease in reliability in a compressor for a refrigeration cycle device and a refrigeration cycle device.
[0012]
[Means for Solving the Problems]
In order to solve the above problems, a first aspect of the present invention (corresponding to claim 1) uses carbon dioxide as a refrigerant, stores at least a compression element and an electric element in a closed container, and uses a mineral oil-based oil. In a compressor for a refrigerating cycle device, which contains a refrigerating machine oil containing at least one selected from an alkylbenzene oil and a mixture thereof, the pressure in the closed vessel is substantially the same as the high-pressure side pressure in the refrigerating cycle, A compressor characterized in that an insulating material of the electric element is made of at least one of polyvinyl formal, polyphenylene sulfide, polyester imide, polyamide, polyamide imide and polyimide.
A second aspect of the present invention (corresponding to claim 2) is the compressor according to the first aspect, wherein the weight content of water contained in the refrigerating machine oil is 100 ppm by weight or less. .
A third aspect of the present invention (corresponding to claim 3) is the compressor according to the first or second aspect, wherein the weight content of water contained in the refrigerating machine oil is 50 ppm by weight or less. It is.
Further, a fourth invention (corresponding to claim 4) provides a refrigeration cycle apparatus in which at least a compressor, a radiator, a decompressor, and a heat absorber are connected, and the compressor according to any one of the first to third inventions as a compressor. A refrigeration cycle apparatus characterized by using the compressor of (1). A fifth aspect of the present invention (corresponding to claim 5) is the fourth aspect of the present invention, wherein the refrigerant between the compressor and the heat absorber and the refrigerant between the radiator and the pressure reducer are different from each other. A refrigeration cycle apparatus further comprising an internal heat exchanger for exchanging heat.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014]
FIG. 1 is a configuration diagram schematically illustrating an example of a compressor for a refrigeration cycle device of the present invention. The compressor shown in FIG. ₂ A refrigerant is used, and a compression element 11 for compressing the refrigerant and an electric element 13 for operating the compression element 11 are provided in the closed container 10, and a refrigerator oil 14 in which the refrigerant is dissolved is stored at the bottom. . Here, the pressure in the closed container 10 is substantially the same as the high pressure side pressure in the refrigeration cycle. The compression element 11 is connected to the electric element 13 by a drive shaft 15, and a compression chamber 110 is formed between the compression elements 11. Further, a refrigerating machine oil path 150 is formed in the drive shaft 15. The electric element 13 is supplied with electricity from a power supply terminal (not shown) via a connection portion (not shown).
[0015]
The electric element 13 is constituted by a cylindrical stator 131 whose outer peripheral surface is supported by the closed casing 10, and a rotor 132 supported by the drive shaft 15 so as to keep a constant distance from the inner peripheral surface of the stator 131. I have. The stator 131 includes a core 16 in which iron plates are stacked in a cylindrical shape, a magnet wire 17 passing through slots formed in a large number in the cylindrical direction of the core 16, a space between the core 16 and the magnet wire 17, and a magnet wire 17. And a binding thread (not shown) binding the magnet wire 17 protruding from the end face of the core 16. Here, the connecting portion of the stator 131, the insulating film 18 and the insulating material such as the binding yarn include at least one selected from heat-resistant polyvinyl formal, polyphenylene sulfide, polyester imide, polyamide, polyamide imide, and polyimide. Use organic materials.
[0016]
Next, the operation of the compressor will be described. When the rotor 132 of the electric element 13 rotates, its rotational power is transmitted to the compression element 11 via the drive shaft 15, and the CO 2 ₂ The refrigerant is sucked from the suction pipe 12 into the compression chamber 110, and as the compression chamber 110 shrinks, CO ₂ The refrigerant is compressed and discharged from the discharge hole 111 into the closed container 10. CO discharged into the closed container 10 ₂ The refrigerant is discharged out of the compressor through the discharge pipe 19. On the other hand, the refrigerating machine oil 14 is supplied to each sliding portion of the compression element 11 via the refrigerating machine oil path 150 by the pump 151. The refrigerating machine oil 14 only needs to lubricate the sliding parts, but actually flows into the compression chamber 110, and as a result, CO 2 ₂ The refrigerant is discharged from the compression chamber 110 via the discharge hole 111 together with the refrigerant.
[0017]
As described above, in the case of the compressor in which the pressure in the closed container 10 is substantially the same as the high-pressure side pressure in the refrigeration cycle, the CO discharged from the discharge hole 111 ₂ Since the refrigerant and the refrigerating machine oil are once discharged into the closed container 10, most of the discharged refrigerating machine oil is CO ₂ It is separated from the refrigerant and stored in the bottom of the closed container 10 again. Therefore, the discharged refrigerating machine oil hinders heat transfer in the radiator and the heat absorber, and can realize an efficient compressor without deteriorating the performance of the refrigeration cycle device. Table 1 shows that the compressor in which the insulating material of the electric element 13 and the weight content of water contained in the refrigerating machine oil 14 were changed was operated for 2000 hours under the test conditions of a discharge pressure of about 10 MPa and a refrigerant discharge temperature of about 160 ° C. The results of examining the degree of deterioration of the insulating material such as oligomer extraction and blister generation are shown.
[0018]
[Table 1]

[0019]
As is evident from Table 1, even if the inside of the closed vessel 10 in which the ambient temperature of the electric element 13 rises is substantially the same as the high-pressure side pressure in the refrigeration cycle, it has been conventionally used as an insulating material. Polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc., the use of polyvinyl formal, polyphenylene sulfide, polyester imide, polyamide, polyamide imide, polyimide, etc., which has excellent heat resistance, deteriorates the insulating material, There is no problem that reliability is reduced.
[0020]
Therefore, the inside of the closed vessel 10 is set to substantially the same pressure as the high pressure side pressure in the refrigeration cycle, and the insulating material of the electric element 13 is at least one of polyvinyl formal, polyphenylene sulfide, polyester imide, polyamide, polyamide imide, and polyimide. Thus, a highly efficient compressor can be realized while avoiding a decrease in reliability.
[0021]
Further, as is apparent from Table 1, the weight content of the water contained in the refrigerating machine oil 14 is preferable for realizing a highly efficient compressor while further reducing the deterioration of the insulating material and avoiding a decrease in reliability. Is preferably 100 ppm by weight or less, more preferably 50 ppm by weight or less. Further, in order to make the weight content of water contained in the refrigerating machine oil 14 preferably 100 ppm by weight or less, more preferably 50 ppm by weight or less, as is clear from Table 2, paraffin oil or naphthene having a low hygroscopicity is used. The use of the refrigerating machine oil 14 containing, as a main component, any one selected from mineral oils such as oils, alkylbenzene oils, and mixtures thereof facilitates water management.
[0022]
[Table 2]

[0023]
Accordingly, using carbon dioxide as a refrigerant, at least the compression element and the electric element are housed in a closed container, and a refrigerating machine oil containing, as a main component, any one selected from a mineral oil, an alkylbenzene oil, and a mixture thereof. In the compressor for a refrigeration cycle device, the inside of the closed vessel is substantially the same pressure as the high pressure side pressure in the refrigeration cycle, and the insulating material of the electric element is polyvinyl formal, polyphenylene sulfide, polyester imide, polyamide, polyamide imide, A compressor characterized by being made of at least one of polyimide is valuable as a highly efficient compressor while avoiding a decrease in reliability. Preferably, the viscosity of the refrigerating machine oil is appropriately set in order to reduce sliding loss due to the refrigerating machine oil. CO ₂ The amount of the refrigerant dissolved in the refrigerating machine oil is small. Therefore, for the above refrigerating machine oil, the kinematic viscosity at 40 ° C. is 40 mm. ² / S or less.
[0024]
The compressor for a refrigeration cycle device of the present invention as described above is used as a compressor in a refrigeration cycle device in which a compressor, a radiator, a decompressor, and a heat absorber are connected. When the refrigeration cycle apparatus further includes an internal heat exchanger that exchanges heat between the refrigerant between the compressor and the heat absorber and the refrigerant between the radiator and the pressure reducer, the refrigerant discharge temperature of the compressor further increases. Therefore, the effect of using the compressor for a refrigeration cycle device of the present invention becomes higher.
[0025]
Also, in a refrigeration cycle apparatus using carbon dioxide as a refrigerant and connecting at least a compressor, a radiator, a decompressor, and a heat sink, a discharge temperature detector for detecting a refrigerant discharge temperature of the compressor; A decompressor discharge temperature controller for adjusting the refrigerant discharge temperature by operating the degree of opening of the decompressor in accordance with the refrigerant discharge temperature detected by the device, an outlet temperature detector for detecting a refrigerant outlet temperature of the radiator, and A decompressor optimal high-pressure controller for adjusting the high pressure by operating the opening of the decompressor in accordance with the refrigerant outlet temperature detected by the outlet temperature detector, and the decompression in accordance with the refrigerant discharge temperature detected by the discharge temperature detector A pressure-reducing device opening degree operating device that switches the device discharge temperature controller and the pressure-reducing device optimal high-pressure controller to control the opening degree of the pressure reducing device, and an evaporation temperature detector that detects a refrigerant evaporation temperature of the heat absorber. The evaporation temperature A compressor according to the present invention as a compressor in a refrigeration cycle device, comprising: a compression function force controller that controls the rotation speed of the compressor according to the refrigerant evaporation temperature detected by the sensor to adjust the capacity. Machine may be used. This refrigeration cycle device is designed to control the decompressor and the compressor properly by the decompressor discharge temperature controller, depressurizer optimal high-pressure controller, decompressor opening controller, and compression function force controller, so that users and the like can According to the required capacity and while maintaining the operation in a state of high efficiency, it is possible to realize an operation in which the refrigerant discharge temperature of the compressor is prevented from rising as the insulating material of the electric element of the compressor is deteriorated. When the compressor of the present invention is used in such a refrigeration cycle apparatus, a decrease in reliability due to deterioration of the insulating material of the conductive element can be more reliably prevented (hereinafter, this refrigeration cycle apparatus according to the embodiment will be described). A).
[0026]
FIG. 2 is a configuration diagram schematically showing the refrigeration cycle apparatus.
The refrigeration cycle apparatus of FIG. ₂ Basic components including a compressor 21, a radiator 22, an internal heat exchanger 23, a pressure reducer 24, and a heat absorber 25 configured to exchange heat between the low pressure side flow path 23a and the high pressure side flow path 23b using a refrigerant. And The low-pressure side flow path 23a of the internal heat exchanger 23 is configured so that the refrigerant flows between the heat absorber 25 and the suction of the compressor 21, and the high-pressure side flow path 23b is connected between the radiator 22 and the pressure reducer 24. Is configured to flow.
In FIG. 2, reference numeral 31 denotes a discharge temperature detector for detecting a refrigerant discharge temperature of the compressor 21, and reference numeral 32 denotes an opening degree of the pressure reducer 24 so that the refrigerant discharge temperature detected by the discharge temperature detector 31 becomes a set temperature. A decompressor discharge temperature controller 33, an outlet temperature detector 33 for detecting a refrigerant outlet temperature of the radiator 22, and a refrigerant outlet temperature detected by the outlet temperature detector 33, a COP (Coefficient of Performance) becomes maximum. Optimum high-pressure calculator for calculating high-pressure side pressure (compressor 21 discharge-radiator 22-internal heat exchanger high-pressure side channel 23b-decompressor 24 inlet) (hereinafter referred to as optimum high pressure) in the refrigeration cycle; The high-pressure detector 36 for detecting the side pressure is provided with a pressure reducing device 2 such that the high-pressure side pressure detected by the high-pressure detector 35 becomes the optimum high pressure calculated by the optimum high-pressure calculator 34. Optimal high-pressure controller for controlling the opening degree of the compressor, 37 switches the output of the decompressor discharge temperature controller 32 and the output of the optimal depressurizer high-pressure controller 36 in accordance with the refrigerant discharge temperature detected by the discharge temperature detector 31 or This is a pressure reducing device opening degree operating device that operates the opening degree of the pressure reducing device 24 by fusing. Reference numeral 41 denotes an evaporation temperature detector for detecting the refrigerant evaporation temperature in the heat absorber 25, and reference numeral 42 denotes a predetermined refrigerant evaporation temperature detected by the evaporation temperature detector 41 so that the heat absorber 25 does not freeze. The compressor frost controller 43 controls the number of revolutions of the compressor 21 so as to be equal to or higher than the refrigerant evaporation temperature (hereinafter, also referred to as a first set temperature). The refrigerant frost controller 43 detects the refrigerant evaporation temperature detected by the evaporation temperature detector 41. A compression function force controller that controls the number of revolutions of the compressor 21 so as to reach a predetermined refrigerant evaporation temperature (hereinafter, referred to as a second set temperature) required to supply a capacity requested by a user or the like; Reference numeral 44 denotes a compressor circuit that switches or fuses the outputs of the compressor frost controller 42 and the compression function force controller 43 in accordance with the refrigerant evaporation temperature detected by the evaporation temperature detector 41 to operate the rotation speed of the compressor 21. It is the number operating device.
[0027]
Of the operation of this refrigeration cycle device, CO ₂ The flow of the refrigerant is as follows. That is, in the figure, the solid arrow indicates CO 2 ₂ 2 shows the flow direction of the refrigerant. CO compressed by the compressor 21 ₂ The refrigerant enters a high temperature and high pressure state and is introduced into the radiator 22. In the radiator 22, CO ₂ Since the refrigerant is in a supercritical state, the refrigerant radiates heat to an external fluid such as air or water without being in a gas-liquid two-phase state. Then, CO ₂ The refrigerant is further cooled in the high-pressure side channel 23b of the internal heat exchanger 23. Further, the pressure is reduced in the pressure reducer 24 to be in a low-pressure gas-liquid two-phase state, and is introduced into the heat absorber 25. In the heat absorber 25, an external fluid such as air or water is cooled and CO ₂ The refrigerant absorbs heat. Thereafter, the gas enters the gas state in the low-pressure side channel 23 a of the internal heat exchanger 23, and is sucked into the compressor 21 again. By repeating such a cycle, the radiator 22 can perform a heating action by heat radiation, for example, heating or water heating, and the heat absorber 25 can perform a cooling action by heat absorption, for example, cooling or dehumidification.
[0028]
This refrigeration cycle apparatus ₂ In the case where the refrigerant is used and the compressor 21 is a compressor in which the pressure in the sealed container is substantially the same as the high pressure side pressure in the refrigeration cycle, the case where conventionally used fluorocarbons are used as the refrigerant, The atmospheric temperature of the electric element of the compressor 21 increases, and the insulating material of the electric element of the compressor 21 deteriorates as compared with the case where a compressor in which the inside of the container has the same pressure as the low pressure side pressure in the refrigeration cycle is used. However, there is a possibility that the reliability of the compressor is reduced.
[0029]
However, in the present embodiment, since the compressor 21 is appropriately operated by the compressor rotation speed operator 44 and the decompressor 24 is appropriately operated by the decompressor opening degree operator 37, Problems can be prevented from occurring. FIG. 3 is a flowchart showing the operation of the compressor 21 by the compressor speed controller 44 and the operation of the pressure reducer 24 by the pressure reducer opening degree controller 37. Hereinafter, description will be made with reference to this flowchart.
[0030]
First, the operation of the compressor 21 will be described. A comparison is made between the refrigerant evaporation temperature detected by the evaporation temperature detector 41 and a first evaporation temperature threshold Te1 (for example, set based on the refrigerant evaporation temperature at which the heat absorber 25 freezes) (Step 201), and the refrigerant evaporation temperature is determined. If the temperature is lower than the first evaporation temperature threshold Te1, the evaporation temperature membership value is set to 0 (step 202). If the refrigerant evaporation temperature is higher than the first evaporation temperature threshold Te1, the temperature is higher than the first evaporation temperature threshold Te1. A comparison is made with a second evaporation temperature threshold Te2 (for example, set to a temperature slightly higher than the refrigerant evaporation temperature at which the heat absorber 25 freezes) (step 203). If the refrigerant evaporation temperature is lower than the second evaporation temperature threshold Te2, An evaporation temperature membership value that changes monotonously and continuously from 0 to 1 according to the temperature is set (step 204), and the refrigerant evaporation temperature is higher than the second evaporation temperature threshold Te2. Sets the evaporation temperature membership value to 1 if (step 205). Note that the first evaporation temperature threshold may be set to the same temperature as the first set temperature, but it is not necessary to stick to this. For example, a temperature slightly lower than the first set temperature may be set. Also, the second evaporation temperature threshold may be set slightly higher than the first evaporation temperature threshold and slightly lower than the first set temperature.
[0031]
Then, the evaporation temperature membership value is subtracted from the product of the rotation speed of the compressor 21 and the evaporation temperature membership value by the compression function force controller 43 and the rotation speed of the compressor 21 by the compressor frost controller 42 and 1. The compressor speed is determined as the sum of the product values of the two values and the compressor 21 is operated (step 206). Here, the compression function force controller 43 determines that the refrigerant evaporation temperature detected by the evaporation temperature detector 41 is equal to the predetermined refrigerant evaporation temperature (the second refrigerant evaporation temperature required to supply the capability requested by the user or the like). This is to determine the rotation speed of the compressor 21 so as to reach the (set temperature) (referred to as capacity control in FIG. 3). On the other hand, the compressor frost controller 42 determines that the refrigerant evaporation temperature detected by the evaporation temperature detector 41 is equal to or higher than a predetermined refrigerant evaporation temperature (first set temperature) so that the heat absorber 25 does not freeze. Thus, the rotation speed of the compressor 21 is determined (referred to as frost prevention control in FIG. 3).
[0032]
That is, when it is determined in step 201 that the refrigerant evaporation temperature detected by the evaporation temperature detector 41 is lower than the first evaporation temperature threshold Te1, the refrigerant evaporation temperature is low and the heat absorber 25 may freeze. Thus, in step 206, the compressor rotation speed by the compressor frost controller 42 is given top priority, and the rotation speed of the compressor 21 is reduced to increase the refrigerant evaporation temperature. When the refrigerant evaporation temperature detected by the evaporation temperature detector 41 is determined to be higher than the first evaporation temperature threshold Te1 in Step 201 and is determined to be higher than the second evaporation temperature threshold Te2 in Step 203, the refrigerant evaporation is performed. Since the temperature is in a state where there is no possibility that the heat absorber 25 is frozen, in Step 206, the compressor rotation speed by the compression function force controller 43 is given the highest priority, and the capacity requested by the user or the like is supplied. The number of revolutions of the compressor is determined so as to reach a predetermined refrigerant evaporation temperature (second set temperature) necessary for the above. At this time, if the refrigerant evaporating temperature detected by the evaporating temperature detector 41 is higher than the second set temperature, it is determined that the capacity is insufficient, and the compression function force controller 43 determines the compressor rotational speed in the increasing direction. Then, the refrigerant circulation amount is increased. Conversely, when the refrigerant evaporation temperature detected by the evaporation temperature detector 41 is lower than the second set temperature, it is determined that the capacity is excessive, and the compression function power controller 43 determines the compressor rotation speed in a decreasing direction, Reduce the amount of refrigerant circulation. When the refrigerant evaporation temperature detected by the evaporation temperature detector 41 is determined to be higher than the first evaporation temperature threshold Te1 in Step 201 and lower than the second evaporation temperature threshold Te2 in Step 203, the refrigerant evaporation is performed. Although the temperature is low and there is no possibility that the heat absorber 25 freezes immediately, it is not so preferable. Therefore, in step 206, the compressor rotation speed by the compressor frost controller 42 and the compression by the compression function force controller 43 are set. Since the compressor 21 is operated by mixing the rotation speed with the machine speed, it is possible to prevent the heat absorber 25 from freezing, and realize an operation in which the refrigerant evaporates at a temperature corresponding to the capacity required by a user or the like.
[0033]
Next, the operation of the pressure reducer 24 will be described. A comparison is made between the refrigerant discharge temperature detected by the discharge temperature detector 31 and a first discharge temperature threshold value Td1 (for example, set based on the upper limit of the allowable use range of the compressor 21) (Step 301), and the refrigerant discharge temperature becomes the second refrigerant temperature. If it is higher than the first discharge temperature threshold Td1, the discharge temperature membership value is set to 0 (step 302), and if the refrigerant discharge temperature is lower than the first discharge temperature threshold Td1, the discharge temperature membership value is lower than the first discharge temperature threshold Td1. A comparison is made with the second discharge temperature threshold Td2 (for example, set based on the upper limit of the normal use range of the compressor 21) (step 303), and when the refrigerant discharge temperature is higher than the second discharge temperature threshold Td2, the refrigerant discharge temperature (Step 304), and if the refrigerant discharge temperature is lower than the second discharge temperature threshold value Td2, the discharge temperature membership value is changed monotonically and continuously in the range from 0 to 1. Out to set the temperature membership value to 1 (step 305).
[0034]
Then, the product of the opening degree of the pressure reducer 24 and the discharge temperature membership value by the pressure reducer optimum high pressure controller 36 and the opening degree of the pressure reducer 24 by the pressure reducer discharge temperature controller 32 and the discharge temperature membership value from 1 The opening of the pressure reducer 24 is determined as the sum of the product amounts of the values obtained by subtracting the above, and the opening of the pressure reducer 24 is operated (step 306). Here, the decompressor optimum high-pressure controller 36 calculates the optimum high-pressure calculator 34 based on the high-pressure side pressure detected by the high-pressure detector 35 based on the refrigerant outlet temperature detected by the outlet temperature detector 33. If the pressure is higher than the high pressure, the opening of the pressure reducer 24 is determined in the increasing direction. If the pressure is lower than the high pressure, the opening of the pressure reducing device 24 is determined in the decreasing direction. . On the other hand, when the refrigerant discharge temperature detected by the discharge temperature detector 31 is higher than a predetermined refrigerant discharge temperature, the depressurizer discharge temperature controller 32 increases the opening degree of the decompressor 24 in the increasing direction. The opening degree of the pressure reducer 24 is determined in a direction in which the opening degree of the pressure reducing unit 24 decreases (referred to as discharge temperature control in FIG. 3).
[0035]
That is, when it is determined in step 301 that the refrigerant discharge temperature detected by the discharge temperature detector 31 is higher than the first discharge temperature threshold Td1, the refrigerant discharge temperature is out of the allowable use range of the compressor 21, and Since the reliability of the pressure reducer 21 is significantly impaired, in step 306, the opening degree of the pressure reducer by the pressure reducer discharge temperature controller 32 is given top priority, and the opening degree of the pressure reducer 24 is increased to lower the refrigerant discharge temperature. . When the refrigerant discharge temperature detected by the discharge temperature detector 31 is determined in step 301 to be lower than the first discharge temperature threshold Td1, and in step 303, the refrigerant discharge temperature is determined to be lower than the second discharge temperature threshold Td2. Since the temperature is within the normal use range of the compressor 21 and there is no problem in the reliability of the compressor 21, in Step 306, the pressure-reducing device opening by the pressure-reducing device optimal high-pressure controller 36 is given the highest priority, and the pressure reducing device Determine the opening. At this time, when the high-pressure side pressure in the refrigeration cycle detected by the high-pressure detector 35 is higher than the optimum high pressure calculated by the optimum high-pressure calculator 34 based on the refrigerant outlet temperature detected by the outlet temperature detector 33. The opening degree of the pressure reducer 24 is determined in the increasing direction by the pressure reducer optimum high pressure controller 36. As a result, the refrigerant on the high pressure side (the discharge from the compressor 21 to the radiator 22 to the high pressure side channel 23b of the internal heat exchanger to the inlet of the pressure reducer 24) is cooled by the refrigerant on the low pressure side (the outlet of the pressure reducer 24 to the heat absorber 25 to the internal heat exchanger). To the low-pressure side flow path 23a to the compressor 21 suction), and the high-pressure side pressure is reduced. Therefore, the high-pressure side pressure can be made to match the optimum high pressure, and operation in a state where the COP is high can be realized. Conversely, when the high-pressure side pressure detected by the high-pressure detector 35 is lower than the optimum high-pressure calculated by the optimum high-pressure calculator 34, the opening of the pressure reducer 24 is determined by the pressure-reducing device optimum high-pressure controller 36 in a decreasing direction. . As a result, the low-pressure side refrigerant moves to the high-pressure side and the high-pressure side pressure rises, so that the high-pressure side pressure can be made to match the optimum high pressure, and operation in a high COP state can be realized. When the refrigerant discharge temperature detected by the discharge temperature detector 31 is determined in step 301 to be lower than the first discharge temperature threshold Td1 and in step 303 to be higher than the second discharge temperature threshold Td2, Since the temperature is within the allowable use range of the compressor 21 but outside the normal use range and is not very desirable from the viewpoint of the reliability of the compressor 21, in Step 306, the decompressor by the decompressor discharge temperature controller 32 is used. By operating the decompressor 24 by mixing the opening of the compressor 24 and the opening of the decompressor 24 by the decompressor optimum high-pressure controller 36, the refrigerant discharge temperature is kept within the normal use range of the compressor 21, The side pressure can be made to match the optimum high pressure, and operation in a high COP state can be realized.
[0036]
By repeating the above operation at regular time intervals, CO2 ₂ Even if the compressor 21 uses a refrigerant and the inside of the closed vessel has the same pressure as the high-pressure side pressure in the refrigeration cycle, the compressor 21 controls the capacity by the compression function force controller 43 and prevents the frost by the compressor frost controller 42. The control of the compressor rotation speed controller 44 switches or fuses the control, thereby preventing the heat absorber 25 from freezing and realizing the operation of the refrigeration cycle device according to the ability requested by the user or the like. By switching or merging the optimal high-pressure control by the optimal high-pressure controller 36 and the discharge temperature control by the decompressor discharge temperature controller 32 with the decompressor opening degree operating device 37, the more the insulating material of the electric element of the compressor 21 is deteriorated, the better. In addition, the refrigeration cycle apparatus can be operated in a highly efficient state while preventing the refrigerant discharge temperature of the compressor 21 from rising.
[0037]
When the heat absorber 25 is a water-cooled heat exchanger or the like and there is no possibility that the heat absorber 25 is frozen, the compressor frost controller 42 is omitted, and the operation of the compressor frost controller It is also possible to omit the part related to 42. Further, the detection of the refrigerant discharge temperature, the refrigerant outlet temperature, and the refrigerant evaporation temperature by the discharge temperature detector 31, the outlet temperature detector 33, and the evaporating temperature detector 41 directly detects the temperatures of the compressor 21, the radiator 22, and the heat absorber 25. It may be detected by measuring, or may be detected indirectly by measuring the ambient temperature of the compressor 21, the radiator 22, and the heat absorber 25. Further, the high pressure detector 35 may directly detect the pressure, or may detect and estimate a part of the state of the refrigeration cycle. Although the optimum high-pressure calculator 34 calculates that the optimum high pressure is calculated based on the temperature detected by the outlet temperature detector 33, the optimum high pressure may be calculated by detecting at least one of the states of the refrigeration cycle. . Further, in the present embodiment, the change of the refrigerant circulation amount by the operation of the compressor 21 has been described as being performed by the rotation speed of the compressor 21, but other means of changing the refrigerant circulation amount by the compressor 21, for example, This may be performed by increasing or decreasing the stroke amount of the piston of the reciprocating compressor.
[0038]
Further, in a refrigeration cycle apparatus using carbon dioxide as a refrigerant and connecting at least a compressor, a radiator, a decompressor, and a heat absorber, the degree of superheat of the refrigerant at any position from the outlet of the heat absorber to the suction of the compressor. A superheat degree calculator that calculates the degree of superheat degree, a depressurizer superheat degree controller that operates the opening degree of the decompressor according to the refrigerant superheat degree calculated by the superheat degree calculator to adjust the refrigerant superheat degree, and the radiator An outlet temperature detector that detects a refrigerant outlet temperature, a decompressor optimal high-pressure controller that controls an opening degree of the decompressor and adjusts a high pressure according to the refrigerant outlet temperature detected by the outlet temperature detector, and the superheat degree A decompressor opening degree manipulator for operating the opening degree of the decompressor by switching between the decompressor superheat degree controller and the decompressor optimum high-pressure controller in accordance with the refrigerant superheat degree calculated by an arithmetic unit, and the heat absorber To detect refrigerant evaporation temperature A refrigeration cycle device comprising: a temperature detector; and a compression function force controller that controls the number of revolutions of the compressor and adjusts the performance in accordance with the refrigerant evaporation temperature detected by the evaporation temperature detector. The compressor of the present invention may be used as a compressor. This refrigeration cycle device is designed to properly control the decompressor and compressor by the decompressor superheat degree controller, depressurizer optimal high-pressure controller, depressor opening controller, and compression function force controller. According to the required capacity and while maintaining the operation in a state of high efficiency, it is possible to realize an operation in which the refrigerant discharge temperature of the compressor is prevented from rising as the insulating material of the electric element of the compressor is deteriorated. When the compressor of the present invention is used in such a refrigeration cycle apparatus, a decrease in reliability due to deterioration of the insulating material of the conductive element can be more reliably prevented (hereinafter, this refrigeration cycle apparatus according to the embodiment will be described). B)).
[0039]
FIG. 4 is a configuration diagram schematically showing the refrigeration cycle apparatus. 4, the same components as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 4, reference numeral 51 denotes a superheat degree calculator for calculating the degree of superheat of the refrigerant at the outlet of the heat absorber 25 (the refrigerant superheat is the difference between the refrigerant temperature at the outlet of the heat absorber 25 and the refrigerant evaporation temperature. The refrigerant superheat degree may be calculated by subtracting the temperature detected by the evaporating temperature detector 41 from the outlet temperature.) 52 is a decompressor 24 so that the refrigerant superheat degree calculated by the superheat degree calculator 51 becomes a set value. The decompressor superheat degree controller 53 for controlling the opening degree of the depressurizer superheat degree controller 52 and the output of the decompressor optimum high-pressure controller 36 are switched according to the refrigerant superheat degree calculated by the superheat degree calculator 51 or This is a pressure reducing device opening degree operating device that operates the opening degree of the pressure reducing device 24 by fusing.
[0040]
This refrigeration cycle apparatus ₂ In the case where the refrigerant is used and the compressor 21 is a compressor in which the pressure in the sealed container is substantially the same as the high pressure side pressure in the refrigeration cycle, the case where conventionally used fluorocarbons are used as the refrigerant, The atmospheric temperature of the electric element of the compressor 21 increases, and the insulating material of the electric element of the compressor 21 deteriorates as compared with the case where a compressor in which the inside of the container has the same pressure as the low pressure side pressure in the refrigeration cycle is used. However, there is a possibility that the reliability of the compressor is reduced.
[0041]
However, in the present embodiment, the compressor 21 is appropriately operated by the compressor rotation speed operator 44 and the decompressor 24 is appropriately operated by the decompressor opening degree operator 53. Problems can be prevented from occurring. FIG. 5 is a flowchart showing the operation of the compressor 21 by the compressor speed controller 44 and the operation of the pressure reducer 24 by the pressure reducer opening degree controller 53. Hereinafter, description will be made with reference to this flowchart.
[0042]
The operation of the compressor 21 is the same as that of (Embodiment A), and the description is omitted.
Next, the operation of the pressure reducer 24 will be described. The refrigerant superheat calculated by the superheat calculator 51 is compared with a first superheat threshold SH1 (for example, set based on the refrigerant superheat at which the refrigerant discharge temperature of the compressor 21 becomes the upper limit of the allowable use range) ( Step 401), if the refrigerant superheat is larger than the first superheat threshold SH1, set the superheat membership value to 0 (Step 402); if the refrigerant superheat is smaller than the first superheat threshold SH1, A comparison is made with a second superheat threshold SH2 that is smaller than the first superheat threshold SH1 (for example, set based on the refrigerant superheat at which the refrigerant discharge temperature of the compressor 21 is at the upper limit of the normal use range) (step 403). If the superheat degree is larger than the second superheat degree threshold value SH2, a superheat degree membership value that changes monotonously and continuously in the range from 0 to 1 according to the refrigerant superheat degree is set (step 404), and the refrigerant superheat is set. Degree If 2 superheating degree threshold SH2 smaller sets the superheat membership value to 1 (step 405).
[0043]
Then, the product of the opening degree of the pressure reducer 24 and the superheat degree membership value by the pressure reducer optimum high pressure controller 36, the opening degree of the pressure reducer 24 by the pressure reducer superheat degree controller 52, and the superheat degree membership value from 1 The opening of the pressure reducer 24 is determined as the sum of the product amounts of the pressure reduction and the opening of the pressure reducer 24 (step 406). Here, the decompressor optimum high-pressure controller 36 calculates the optimum high-pressure calculator 34 based on the high-pressure side pressure detected by the high-pressure detector 35 based on the refrigerant outlet temperature detected by the outlet temperature detector 33. If the pressure is higher than the high pressure, the opening of the pressure reducer 24 is determined in the increasing direction. If the pressure is lower than the high pressure, the opening of the pressure reducing device 24 is determined in the decreasing direction. . On the other hand, if the degree of superheat calculated by the degree of superheat calculator 51 is greater than a predetermined degree of superheat, the degree of opening of the pressure reducer 24 is increased. The degree of opening of the pressure reducer 24 is determined in the direction of decreasing the degree of opening (referred to as superheat degree control in FIG. 5).
[0044]
That is, when it is determined in step 401 that the refrigerant superheat calculated by the superheat calculator 51 is larger than the first superheat threshold SH1, the refrigerant discharge temperature of the compressor 21 is allowed because the refrigerant superheat is large. Since the range is out of the range and the reliability of the compressor 21 is significantly impaired, in Step 406, the opening degree of the depressurizer 24 is increased by giving the highest priority to the opening degree of the depressurizer by the depressurizer superheat degree controller 52. Thus, the refrigerant discharge temperature is reduced by reducing the degree of superheat of the refrigerant. When it is determined in step 401 that the superheat degree of the refrigerant calculated by the superheat degree calculator 51 is smaller than the first superheat degree threshold SH1, and in step 403 it is determined that the refrigerant superheat degree is smaller than the second superheat degree threshold SH2, Since the temperature is an appropriate value and the refrigerant discharge temperature of the compressor 21 is within the normal use range of the compressor 21 and there is no problem in reliability, in Step 406, the decompressor is opened by the decompressor optimal high-pressure controller 36. The degree of decompressor opening is determined with priority given to the degree. At this time, when the high-pressure side pressure in the refrigeration cycle detected by the high-pressure detector 35 is higher than the optimum high pressure calculated by the optimum high-pressure calculator 34 based on the refrigerant outlet temperature detected by the outlet temperature detector 33. The opening degree of the pressure reducer 24 is determined in the increasing direction by the pressure reducer optimum high pressure controller 36. As a result, the high-pressure side refrigerant moves to the low-pressure side and the high-pressure side pressure decreases, so that the high-pressure side pressure can be made to match the optimum high pressure, and operation in a state where the COP is high can be realized. Conversely, when the high-pressure side pressure detected by the high-pressure detector 35 is lower than the optimum high-pressure calculated by the optimum high-pressure calculator 34, the opening of the pressure reducer 24 is determined by the pressure-reducing device optimum high-pressure controller 36 in a decreasing direction. . As a result, the low-pressure side refrigerant moves to the high-pressure side and the high-pressure side pressure rises, so that the high-pressure side pressure can be made to match the optimum high pressure, and operation in a high COP state can be realized. When the refrigerant superheat calculated by the superheat calculator 51 is determined in step 401 to be smaller than the first superheat threshold SH1 and in step 403 to be larger than the second superheat threshold SH2, the compressor Since the refrigerant discharge temperature of the refrigerant 21 is within the allowable use range of the compressor 21 but out of the normal use range and the refrigerant superheat degree is not so preferable from the viewpoint of the reliability of the compressor 21, the decompressor Since the opening degree of the decompressor 24 by the superheat degree controller 52 and the opening degree of the decompressor 24 by the optimal decompressor high-pressure controller 36 are mixed to operate the decompressor 24, the refrigerant discharge temperature becomes lower than that of the compressor 21. The high-pressure side pressure can be made to match the optimum high pressure while the superheat degree of the refrigerant within the usage range is maintained, and operation in a state where the COP is high can be realized.
[0045]
By repeating the above operation at regular time intervals, CO2 ₂ Even if the compressor 21 uses a refrigerant and the inside of the closed vessel has the same pressure as the high-pressure side pressure in the refrigeration cycle, the compressor 21 controls the capacity by the compression function force controller 43 and prevents the frost by the compressor frost controller 42. The control of the compressor rotation speed controller 44 switches or fuses the control, thereby preventing the heat absorber 25 from freezing and realizing the operation of the refrigeration cycle device according to the ability requested by the user or the like. By switching or merging the depressurizer opening degree operator 53 between the optimal high-pressure control by the optimal high-pressure controller 36 and the superheat control by the decompressor superheat degree controller 52, the quality of the insulating material of the electric element of the compressor 21 changes. In addition, the refrigeration cycle apparatus can be operated in a highly efficient state while preventing the refrigerant discharge temperature of the compressor 21 from rising.
[0046]
In the present embodiment, the superheat degree calculator 51 has been described as calculating the refrigerant superheat degree from the outlet of the heat absorber 25 to the inlet of the low-pressure side flow passage 23a of the internal heat exchanger. It is also possible to calculate the degree of superheat of the refrigerant in the side flow passage or from the outlet of the low-pressure flow passage 23a of the internal heat exchanger to the suction of the compressor 21.
[0047]
Further, in a refrigeration cycle apparatus using carbon dioxide as a refrigerant and connecting at least a compressor, a radiator, a decompressor, and a heat sink, the refrigerant dryness at any position from the heat sink outlet to the compressor suction. A dryness calculator that calculates the dryness calculator, a pressure reducer dryness controller that controls the degree of dryness of the refrigerant by operating the opening degree of the pressure reducer according to the refrigerant dryness calculated by the dryness calculator, and An outlet temperature detector for detecting a refrigerant outlet temperature, a decompressor optimum high-pressure controller for adjusting the high pressure by operating the opening of the decompressor in accordance with the refrigerant outlet temperature detected by the outlet temperature detector, and the dryness A decompressor opening operation device for switching the decompressor dryness controller and the decompressor optimum high-pressure controller in accordance with the refrigerant dryness calculated by the computing unit to operate the opening of the decompressor; and the heat absorber To detect refrigerant evaporation temperature A refrigeration cycle device comprising: a temperature detector; and a compression function force controller that controls the number of revolutions of the compressor and adjusts the performance in accordance with the refrigerant evaporation temperature detected by the evaporation temperature detector. The compressor of the present invention may be used as a compressor. This refrigeration cycle device is designed to control the decompressor and the compressor properly by the decompressor dryness controller, decompressor optimal high-pressure controller, decompressor opening controller, and compression function force controller. According to the required capacity and while maintaining the operation in a state of high efficiency, it is possible to realize an operation in which the refrigerant discharge temperature of the compressor is prevented from rising as the insulating material of the electric element of the compressor is deteriorated. When the compressor of the present invention is used in such a refrigeration cycle apparatus, a decrease in reliability due to deterioration of the insulating material of the conductive element can be more reliably prevented (hereinafter, this refrigeration cycle apparatus according to the embodiment will be described). C).
[0048]
FIG. 6 is a configuration diagram schematically showing the refrigeration cycle apparatus. The same components as those in FIG. 4 are denoted by the same reference numerals or are omitted from the drawing, and description thereof is omitted. In FIG. 6, reference numeral 61 denotes a dryness calculator for calculating the dryness of the refrigerant at the outlet of the heat absorber 25, and 62 denotes the opening of the pressure reducer 24 so that the dryness of the refrigerant calculated by the dryness calculator 61 becomes a set value. The depressurizer dryness controller 63 controls the output of the depressurizer dryness controller 62 and the decompressor optimum high-pressure controller 36 in accordance with the refrigerant dryness calculated by the dryness calculator 61 or merges. This is a pressure reducer opening degree operation device that operates the opening degree of the pressure reducer 24. The dryness calculator 61 calculates the refrigerant based on the refrigerant discharge temperature detected by the discharge temperature detector 31, the high-pressure side pressure in the refrigeration cycle detected by the high-pressure detector 35, and the refrigerant evaporation temperature detected by the evaporation temperature detector 41. Calculate the dryness. That is, the point 1 is obtained from the refrigerant discharge temperature Td detected by the discharge temperature detector 31 and the high pressure side pressure Ph detected by the high pressure detector 35 from the Mollier diagram shown in FIG. The intersection of the straight line passing through the point 1 of the slope s of the entropy in consideration of the efficiency of the compressor and the low-pressure side pressure Pe obtained by calculating the refrigerant evaporation temperature Te detected by the evaporation temperature detector 41 as the saturation temperature is represented by a point 2 Is required. The degree of dryness may be obtained from the relationship between the determined enthalpy at point 2 and the enthalpy at points L and V, which can be calculated from the refrigerant evaporation temperature Te or the low-pressure side pressure Pe.
[0049]
FIG. 8 is a flowchart showing the operation of the compressor 21 by the compressor speed controller 44 and the operation of the pressure reducer 24 by the pressure reducer opening degree controller 63. Hereinafter, description will be made with reference to this flowchart.
[0050]
The operation of the compressor 21 is the same as that of (Embodiment A) and (Embodiment B), and thus the description is omitted.
Next, the operation of the pressure reducer 24 will be described. A comparison is made between the refrigerant dryness calculated by the dryness calculator 61 and the first dryness threshold χ1 (for example, set based on the refrigerant dryness at which the refrigerant discharge temperature of the compressor 21 becomes the upper limit of the allowable use range) ( Step 501), if the refrigerant dryness is greater than the first dryness threshold χ1, the dryness membership value is set to 0 (Step 502); if the refrigerant dryness is smaller than the first dryness threshold χ1, A comparison is made with a second dryness threshold よ り 小 さ い 2 smaller than the first dryness threshold χ1 (for example, set based on the refrigerant dryness at which the refrigerant discharge temperature of the compressor 21 is at the upper limit of the normal use range) (step 503), If the dryness is greater than the second dryness threshold χ2, a dryness membership value that changes monotonously and continuously in a range from 0 to 1 according to the dryness of the refrigerant is set (step 504). The degree is the second dryness threshold χ If less than it sets the dryness of membership value to 1 (step 505).
[0051]
Then, the product of the opening degree of the pressure reducer 24 and the dryness membership value by the pressure reducer optimum high pressure controller 36, the opening degree of the pressure reducer 24 by the pressure reducer dryness controller 62, and the dryness membership value from 1 Then, the opening of the pressure reducer 24 is determined as the sum of the product amount with the value obtained by subtracting, and the opening of the pressure reducer 24 is operated (step 506). Here, the decompressor optimum high-pressure controller 36 calculates the optimum high-pressure calculator 34 based on the high-pressure side pressure detected by the high-pressure detector 35 based on the refrigerant outlet temperature detected by the outlet temperature detector 33. If the pressure is higher than the high pressure, the opening of the pressure reducer 24 is determined in the increasing direction. If the pressure is lower than the high pressure, the opening of the pressure reducing device 24 is determined in the decreasing direction. . On the other hand, if the dryness calculated by the dryness calculator 61 is greater than a predetermined dryness, the decompressor dryness controller 62 increases the opening of the decompressor 24 in the increasing direction. This is for determining the opening of the pressure reducer 24 in the direction of decreasing the opening (in FIG. 8, it is called dryness control).
[0052]
That is, when it is determined in step 501 that the refrigerant dryness calculated by the dryness calculator 61 is larger than the first dryness threshold χ1, the refrigerant discharge temperature of the compressor 21 is allowed because the refrigerant dryness is large. Since the range is out of the range and the reliability of the compressor 21 is significantly impaired, in Step 506, the opening degree of the depressurizer 24 is increased by giving the highest priority to the opening degree of the depressurizer by the depressurizer dryness controller 62. As a result, the refrigerant discharge temperature is lowered by reducing the dryness of the refrigerant. On the other hand, when it is determined in step 501 that the refrigerant dryness calculated by the dryness calculator 61 is smaller than the first dryness threshold ５０1, and in step 503 it is smaller than the second dryness threshold χ2, the refrigerant dryness is determined. Since the temperature is an appropriate value and the refrigerant discharge temperature of the compressor 21 is within the normal use range of the compressor 21 and there is no problem in reliability, in step 506, the decompressor is opened by the decompressor optimal high-pressure controller 36. The degree of decompressor opening is determined with priority given to the degree. At this time, when the high-pressure side pressure in the refrigeration cycle detected by the high-pressure detector 35 is higher than the optimum high pressure calculated by the optimum high-pressure calculator 34 based on the refrigerant outlet temperature detected by the outlet temperature detector 33. The opening degree of the pressure reducer 24 is determined in the increasing direction by the pressure reducer optimum high pressure controller 36. As a result, the high-pressure side refrigerant moves to the low-pressure side and the high-pressure side pressure decreases, so that the high-pressure side pressure can be made to match the optimum high pressure, and operation in a state where the COP is high can be realized. Conversely, when the high-pressure side pressure detected by the high-pressure detector 35 is lower than the optimum high-pressure calculated by the optimum high-pressure calculator 34, the opening of the pressure reducer 24 is determined by the pressure-reducing device optimum high-pressure controller 36 in a decreasing direction. . As a result, the low-pressure side refrigerant moves to the high-pressure side and the high-pressure side pressure rises, so that the high-pressure side pressure can be made to match the optimum high pressure, and operation in a high COP state can be realized. If it is determined in step 501 that the refrigerant dryness calculated by the dryness calculator 61 is smaller than the first dryness threshold χ1, and if it is determined in step 503 that it is larger than the second dryness threshold χ2, the compressor Although the refrigerant discharge temperature of the refrigerant 21 is within the allowable use range of the compressor 21 but out of the normal use range, the refrigerant dryness is in a state that is not preferable from the viewpoint of the reliability of the compressor 21, so that the decompressor Since the opening degree of the decompressor 24 by the dryness controller 62 and the opening degree of the decompressor 24 by the optimal decompressor high-pressure controller 36 are mixed to operate the decompressor 24, the refrigerant discharge temperature is lower than that of the compressor 21. The high-pressure side pressure can be made to match the optimum high pressure while maintaining the dryness of the refrigerant within the usage range, and operation in a state where the COP is high can be realized.
[0053]
That is, in the present embodiment, similarly to (Embodiment A) and (Embodiment B), since the decompressor 24 is appropriately operated by the decompressor opening degree operating device 63, CO ₂ Even if the compressor 21 uses a refrigerant and the inside of the closed vessel has the same pressure as the high-pressure side pressure in the refrigeration cycle, the compressor 21 controls the capacity by the compression function force controller 43 and prevents the frost by the compressor frost controller 42. The control of the compressor rotation speed controller 44 switches or fuses the control, thereby preventing the heat absorber 25 from freezing and realizing the operation of the refrigeration cycle device according to the ability requested by the user or the like. By switching or merging the optimal high-pressure control by the optimal high-pressure controller 36 and the dryness control by the decompressor dryness controller 62 with the depressurizer opening degree operating unit 63, the quality of the insulating material of the electric element of the compressor 21 changes. In addition, the refrigeration cycle apparatus can be operated in a highly efficient state while preventing the refrigerant discharge temperature of the compressor 21 from rising.
[0054]
An evaluation was performed by using a refrigeration cycle apparatus having the configuration as in (Embodiment B) and a refrigeration cycle apparatus having a configuration as in (Embodiment C), and the refrigerant was superheated at the outlet of the heat absorber 25 as shown in FIG. The relationship between the temperature or the dryness of the refrigerant and the refrigerant discharge temperature of the compressor 21 was obtained. The vertical axis of FIG. 9A is the difference based on the refrigerant discharge temperature when the refrigerant superheat degree is 0K, and the horizontal axis is the difference axis based on the suction enthalpy when the refrigerant superheat degree is 0K. The axis of the degree and the refrigerant dryness are shown together. According to FIG. 9A, in the region where the refrigerant superheat degree is 0K or more (that is, the refrigerant dryness is 1.0 or more), the region where the refrigerant dryness is 1.0 or less (that is, the refrigerant superheat degree is 0K or less) is more effective in increasing the suction enthalpy. It can be seen that the rise in the refrigerant discharge temperature is large. That is, in order to reduce the rise in the refrigerant discharge temperature and prevent the insulating material of the electric element of the compressor 21 from being deteriorated, the refrigerant superheat degree at the outlet of the heat absorber 25 is 0K or less, that is, the refrigerant dryness is 1. It is desirable to control so as to be 0 or less. Next, the result of the capability measurement is shown in FIG. The vertical axis of FIG. 9 (b) is a ratio where the capacity at a refrigerant superheat of 0K is 100. According to FIG. 9B, when the dryness of the refrigerant at the outlet of the heat absorber 25 is 0.8 or less, the enthalpy difference between the inlet and the outlet of the heat absorber 25 decreases. It can be seen that, despite the adjustment of refrigeration, the capacity is reduced and the refrigeration cycle apparatus does not function sufficiently. Therefore, in consideration of both of these characteristics, it is desirable to control the dryness of the refrigerant so as to be 0.8 or more and 1.0 or less.
[0055]
【The invention's effect】
As is apparent from the above description, according to the present invention, carbon dioxide is used as a refrigerant, at least the compression element and the electric element are housed in a closed vessel, and the inside of the closed vessel is at a high pressure side pressure in a refrigeration cycle. Even a compressor for a refrigeration cycle device having substantially the same pressure, using at least one of polyvinyl formal, polyphenylene sulfide, polyester imide, polyamide, polyamide imide, polyimide excellent in heat resistance as an insulating material, and The use of refrigerating machine oil containing at least one selected from the group consisting of mineral oil, alkylbenzene oil and a mixture thereof increases the ambient temperature of the electric element and alters the insulating material. Thus, a highly efficient compressor can be realized without lowering the reliability of the compressor.
Further, when the weight content of water contained in the refrigerating machine oil enclosed in the compressor is 100 wt ppm or less, preferably 50 wt ppm or less, the insulating material is deteriorated and the reliability of the compressor is reduced. It can be further prevented.
Here, by using a refrigerating machine oil having as a main component any one selected from a mineral oil-based oil, an alkylbenzene oil and a mixture thereof having a low hygroscopicity, the weight content of water contained in the refrigerating machine oil can be reduced to 100% by weight. ppm or less, desirably 50 ppm by weight or less facilitates moisture management.
Further, if the compressor is used, the reliability of the compressor is not reduced and CO2 is reduced. ₂ Since the refrigerating machine oil discharged together with the refrigerant can be reduced, the refrigerating machine oil discharged disturbs the heat transfer in the radiator and the heat sink, and does not reduce the performance of the refrigerating cycle device. Can be realized.
[Brief description of the drawings]
FIG. 1 is a configuration diagram schematically showing an example of a compressor for a refrigeration cycle device of the present invention.
FIG. 2 is a configuration diagram schematically showing a refrigeration cycle apparatus (Embodiment A) in which the compressor for a refrigeration cycle apparatus of the present invention is suitably used.
FIG. 3 is a flowchart showing the operation of the refrigeration cycle apparatus.
FIG. 4 is a configuration diagram schematically showing a refrigeration cycle apparatus (Embodiment B) in which the compressor for a refrigeration cycle apparatus of the present invention is preferably used.
FIG. 5 is a flowchart showing the operation of the refrigeration cycle apparatus.
FIG. 6 is a configuration diagram schematically showing a refrigeration cycle apparatus (Embodiment C) in which the compressor for a refrigeration cycle apparatus of the present invention is preferably used.
FIG. 7 is a Mollier diagram showing the relationship between refrigerant superheat or refrigerant dryness and refrigerant discharge temperature, high pressure, and low pressure.
FIG. 8 is a flowchart showing the operation of the refrigeration cycle apparatus.
FIG. 9 shows the relationship between refrigerant superheat or refrigerant dryness and refrigerant discharge temperature.
FIG. 10 is a configuration diagram schematically showing a conventional refrigeration cycle device.
[Explanation of symbols]
1,21 Compressor
2,22 radiator
3,23 Internal heat exchanger
4, 24 decompressor
5, 25 heat absorber
10 Closed container
11 Compression element
110 Compression chamber
111 discharge hole
12 suction pipe
13 Electric elements
131 Stator
132 rotor
14 Refrigeration oil
15 Drive shaft
150 Refrigerator oil path
151 pump
16 cores
17 Magnet wire
18 Insulating film
19 Discharge pipe
31 Discharge temperature detector
32 Decompressor discharge temperature controller
33 outlet temperature detector
34 Optimal high-pressure calculator
35 High pressure detector
36 Optimal high pressure controller for pressure reducer
37, 53, 63 Pressure reducer opening degree controller
41 Evaporation temperature detector
42 Compressor frost controller
43 Compression function force controller
44 Compressor speed controller
51 Superheat degree calculator
52 Decompressor superheat controller
61 Dryness calculator
62 Decompressor dryness controller

Claims (5)

Using carbon dioxide as a refrigerant, at least the compression element and the electric element are housed in a closed container, and a refrigerator oil mainly composed of one selected from mineral oil, alkylbenzene oil and a mixture thereof is enclosed. In the compressor for a refrigeration cycle device, the pressure in the closed vessel is substantially the same as the high pressure side pressure in the refrigeration cycle, and the insulating material of the electric element is polyvinyl formal, polyphenylene sulfide, polyester imide, polyamide, polyamide imide, or polyimide. A compressor comprising at least one of the above. The compressor according to claim 1, wherein a weight content of water contained in the refrigerating machine oil is 100 ppm by weight or less. The compressor according to claim 1 or 2, wherein the weight content of water contained in the refrigerating machine oil is 50 ppm by weight or less. A refrigeration cycle apparatus comprising at least a compressor, a radiator, a decompressor, and a heat absorber, wherein the compressor according to any one of claims 1 to 3 is used as the compressor. The refrigeration cycle according to claim 4, further comprising an internal heat exchanger that exchanges heat between the refrigerant between the compressor and the heat absorber and the refrigerant between the radiator and the pressure reducer. apparatus.

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