【０００１】
【発明の属する技術分野】
本発明は、二酸化炭素など超臨界となる冷媒を用いた冷凍サイクルによる冷凍空調装置に関するものである。
【０００２】
【従来の技術】
従来の密閉形膨張機内蔵圧縮機では、密閉容器７に一本の駆動軸８により互いに動力伝達を受ける膨張機構部９と圧縮機構部１０を収納し、この圧縮機構部１０はモータ１１によって駆動され、圧縮吸入管１８から吸入した冷媒ガスを圧縮し、吐出ポート１９より密閉容器７内に吐出する。そして、密閉容器の上部に設けた圧縮吐出管２０から流出して冷媒回路の凝縮器を経た冷媒は膨張吸入管１６から吸入され、膨張機用シリンダ１２内で減圧・膨張して膨張吐出管１７から吐出し、冷媒回路の蒸発器を経て圧縮吸入管１８に戻る。冷媒が膨張機構部９を通過するときの膨張過程で発生した動力は駆動軸８を介して圧縮機構部１０側の圧縮動力の一部として回収され、モータ１１の出力が軽減されるものがある（例えば、特許文献１参照）。
【０００３】
また、第２の従来の膨張機内蔵圧縮機では、密閉容器７の下部に圧縮機構部１０、上部には膨張機構部９を配設し、これらの間の中央部にモータ１１が配置され、モータの駆動軸８の下端部が圧縮機構部１０に連結され、上端部が膨張機構部９に連結されている。密閉容器の上部に設けた膨張吸入管１６から冷媒が吸入され、スクロール式の膨張機構部９内で膨張し、膨張吐出管１７から吐出される冷媒の膨張過程からの回収動力は、駆動軸８を介してモータ１１による圧縮機構部１０の駆動動力の一部として用いられるものがある（例えば、特許文献２参照）。
【０００４】
また、第３の従来例として、ランキンサイクル駆動空調システム用膨張機内蔵圧縮機において、密閉容器７内の右側に膨張機構部９が、左側に圧縮機構部１０がそれぞれ配置され、冷凍サイクルを構成する圧縮機構部１０の吐出ガスとランキンサイクルを構成する膨張機構部９の吐出ガスが密閉容器ケース７に吐出される一流体方式となっている。膨張吸入管１６から吸入されたランキンサイクル側の高圧冷媒ガスは、膨張機構部９で減圧された後、密閉容器７内に吐出される。減圧の過程で回収された膨張動力が駆動軸８及び継手６５、圧縮機構部の駆動軸６３を介して圧縮機構部１０を駆動し、圧縮吸入管１８から吸入された冷凍サイクル側の低圧冷媒ガスを圧縮する。そして、圧縮された冷媒ガスは密閉容器７内で膨張機構部９で膨張後の冷媒ガスと合流し、吐出管１７からランキンサイクル側と冷凍サイクル側それぞれの回路へ分岐されるようになっている（例えば、特許文献３参照）。
【０００５】
【特許文献１】
特開昭５９−２５０９７号公報（第２頁、第７図）
【特許文献２】
特開２００１−１０７８８１号公報（第３−４頁、第１図）
【特許文献３】
特開平９−２５０４７４号公報（第２−３頁、第１図）
【０００６】
【発明が解決しようとする課題】
上述第３の従来例は、膨張機構部９が図６に示すランキンサイクルの膨張過程、圧縮機構部１０が図６に示す冷凍サイクルの圧縮過程に用いられ、膨張後と圧縮後の冷媒ガスの状態量が同じとなる所謂一流体方式に対応しているので、密閉容器７内を一つの空間として用いることが可能である。なお、図６は縦軸に圧力、横軸にエンタルピとしたモリエル線図に、圧縮、凝縮、膨張、蒸発の各過程を示すものである。
【０００７】
これに対して、ランキンサイクルではなく冷凍サイクルにおける膨張過程で回収した動力を圧縮過程の圧縮動力の一部として利用する場合、圧縮後と膨張前が共に高圧、或いは膨張後と圧縮前が共に低圧、であっても状態量は異なるのでこれを一流体として密閉容器内で合流させて用いることはできない。
【０００８】
また、上述第２の従来例では、密閉容器の内部は膨張機構部側空間が膨張機の吐出すなはち低圧雰囲気で、モータ及び圧縮機構部のある側が圧縮機の吐出すなはち高圧雰囲気となっている。 このため膨張機構部を保持するフレームを貫通する駆動軸には、差圧による軸方向の力が作用するとともに、軸受の微小なすきまを介して高低圧をシールすることになる。
【０００９】
また、上述第１の従来例では、密閉容器内は圧縮機構部の吐出圧雰囲気となっており、駆動軸に軸方向力が作用することはないが、可動部品である駆動軸及びローリングピストンの微小すきまで高低圧をシールする必要がある。
【００１０】
さらに、密閉容器内が高圧で圧縮機構部の可動部品の微小すきまで高低圧をシールしなければならないという状況は、通常のローリングピストン式の冷媒圧縮機でも同様であるが、二酸化炭素など超臨界となる作動冷媒の場合は差圧が大きくなるため、圧縮機であれば二段圧縮で密閉容器内を中間圧雰囲気にするなど、差圧を小さく抑える工夫をすることが必要である。
【００１１】
以上のように、冷凍サイクルの膨張過程から動力を回収し圧縮過程の動力の一部として利用するような膨張機においては、膨張機構部と圧縮機構部の間で駆動軸などによる動力の伝達を行ないながら、作動冷媒の圧力または状態量の異なる空間を隔離しなければならない。
【００１２】
本発明は、かかる課題を解消するためになされたもので、膨張機構部と圧縮機構部を一つの密閉容器に収めた膨張機において、膨張側と圧縮側との差圧をシールすることによる摺動等の損失を低く抑えながら、膨張機構部と圧縮機構部を確実に分離する膨張機内蔵圧縮機を用いた冷凍空調装置を得ることを目的とする。
【００１３】
【課題を解決するための手段】
この発明に係わる冷凍空調装置は、電動機によって駆動される第１圧縮機と、第１圧縮機で圧縮された高圧の冷媒ガスを冷却するガスクーラと、ガスクーラによって冷却された冷媒ガスを減圧することにより動力を回収する膨張機構部と、膨張機構部により減圧された冷媒を加熱する蒸発器と、膨張機構部と同一の密閉容器に内設され膨張機構部の回収動力により駆動される第２圧縮機とを備え、第１圧縮機と第２圧縮機は冷媒配管により直列に接続されるとともに、密閉容器内の第２圧縮機が内設された空間は二段圧縮の中間圧力で満たされるように構成したものである。
【００１４】
また、第２圧縮機は第１圧縮機による圧縮後の冷媒を圧縮し、密閉容器内の膨張機構部が内設された空間は高圧雰囲気となるように構成したものである。
【００１５】
また、第１圧縮機は第２圧縮機による圧縮後の冷媒を圧縮し、密閉容器内の膨張機機構部が内設された空間は低圧雰囲気となるように構成したものである。
【００１６】
また、冷媒として二酸化炭素を用いたものである。
【００１７】
【発明の実施の形態】
実施の形態１．
以下この発明の実施の形態１について説明する。 図１は本発明に係る冷凍空調装置に用いる動力回収ができる膨張機の断面図で、この膨張機により回収する動力で駆動する圧縮機構部を二段圧縮の高段側となる第２圧縮機として用いるものである。 図１の膨張機１は、密閉容器７内部の左側に膨張機構部９、もう一方の右側に第２圧縮機となる圧縮機構部１０を内設し、それぞれを駆動軸６３で連結して回転動力を伝達する構成となっている。図において、密閉容器７内で膨張側フレーム３３に固定された膨張機構部９側の密閉容器７内空間に膨張吸入管１６より吸入された高圧の冷媒ガスは、固定スクロール１２、揺動スクロール１５よりなる膨張機構部９で減圧され、膨張後の冷媒は膨張吐出管１７から直接蒸発器へ排出される。
【００１８】
冷媒の膨張過程において回収された動力は、膨張機構部９側の揺動スクロール１５に固定した膨張側駆動軸８と、この膨張側駆動軸８の回転を圧縮側駆動軸６３に伝達する継手６５から圧縮側駆動軸６３を介して圧縮側フレーム２４に固定された圧縮機構部１０側の揺動スクロール２３に伝えられる。冷媒配管で接続された後述する第１圧縮機９９で圧縮された後、密閉容器７の圧縮機構側に設けられた圧縮吸入管１８から密閉容器内部に流入した高圧凝縮と低圧蒸発の間にある中間圧の冷媒ガスは、上記膨張機構部９における膨張過程による回収動力により、圧縮側の揺動スクロール２３と固定スクロール１２との相互動作による高段の圧縮行程が行われ、圧縮機構部１０から密閉容器７内に流出することなく直接圧縮吐出管２０から直接ガスクーラへ排出される構成である。
【００１９】
上記のように構成された膨張機では一つの密閉容器７内の空間が、膨張側フレーム３３を有した膨張機構部９側は高圧冷媒の状態、一方、継手６５および圧縮側駆動軸６３から圧縮機構部１０側は中間圧冷媒の状態となり、膨張側フレーム３３にある膨張側駆動軸８の軸受け保持部に設けたシール部材６４が高圧／中間圧間の差圧をシールする。 膨張過程における回収動力は作動冷媒のガスクーラと蒸発器間における高低圧間の全圧縮動力に対する割合としては大きくない（１／３以下）ので、この二段圧縮における中間圧は高圧に近い中間圧となり、密閉容器７内の膨張機構部側と圧縮機構部側との間をシールしなければならない差圧は小さくなる。しかし、前述のように圧縮吐出管２０から吐出後、ガスクーラを通過して膨張吸入管１６に流入する過程のなかで、冷媒はこのガスクーラ前後で過熱ガスから過冷却域の液または超臨界状態へと状態量が異なっているので確実に冷媒を分離しなければならない。
【００２０】
膨張機構部９側の容器内空間と圧縮機構部１０側の容器内空間の隔離に関しては、前述の第２の従来例のように駆動軸／フレーム間のすべり軸受すきまによりシールするという方法も考えられるが、非接触シールの場合はある程度の漏れを許容しなければならない。 これに対して図１に示す形態では、膨張側フレーム３３と膨張側駆動軸８間の接触式のシール部材６４により確実にシールすることが可能であるが摺動ロスが生じるので、これが過大とならないようにシールする差圧をできるだけ小さくすことが必要であり、本発明の動力回収できる膨張機ではシール前後を高圧と中間圧になるようにしているので、圧縮機構部側と膨張機構部側とを確実にシールしながら、このシールに伴う摺動損失を少なくすることができ、動力回収効率の良い高性能のＣＯ２冷媒を用いた超臨界サイクルによる冷凍空調装置を得ることができる。
【００２１】
このような構成の膨張機を用いた冷凍空調装置の冷媒回路を図２に示す。図２（ａ）は冷房運転を示し、超臨界となる二酸化炭素の冷媒を用い、低圧（Ｐｌ）の冷媒はモータにより駆動される低段側の第１圧縮機９９で圧縮されて中間圧（Ｐｈ−ΔＰ）となり、その後、第１圧縮機９９に直列に配管接続された膨張機１内設の高段側となる圧縮機構部１０に吸入・圧縮され、高圧（Ｐｈ）のガス状態で四方弁９２を経て凝縮行程を行ないガスクーラとなる室外機熱交換器９８に至る。このガスクーラで冷却された冷媒は、膨張機１の膨張機構部９で減圧する過程で動力回収され、圧縮機構部１０におけるガス圧縮動力を供給する。この膨張機構部９で減圧されて低圧（Ｐｌ）となった冷媒は、蒸発器となる室内機熱交換器９７で加熱され、その後、四方弁９２、アキュムレータ９３を経て再び低段側の第１圧縮機９９に戻り、冷凍サイクルを形成する。
【００２２】
このとき、第１圧縮機９９の形式（スクロール圧縮、ロータリー圧縮等）及び密閉容器内が吸入圧であるか吐出圧であるかは問わないが、この実施の形態では高段側の第２圧縮機となる膨張機１内設の圧縮機構部１０での密閉容器７内空間は、第１圧縮機９９吐出側の中間圧雰囲気（Ｐｈ−Δ）としている。 潤滑が必要な第１圧縮機９９と膨張機１に内設の圧縮機構部１０および膨張機構部９の３ヶ所に潤滑油を保持し、図１に示す膨張側フレーム３３に設けられ密閉容器７内の膨張側空間と圧縮側空間を繋ぐ微小孔７０と油戻し毛細管７１により密閉容器７内に貯留される潤滑油量をバランスさせる。第１圧縮機９９と膨張機１に内設した圧縮機構部１０に関しては必要レベルの油持出しを許容し、膨張機構部９入口の空間部分で油循環率極小化を図ることができる。膨張機構部９側から微小孔７０を介して圧縮機構部１０側へ、圧縮機構部１０側からアキュムレータ９３と第１圧縮機９９間の冷媒配管へ油戻し毛細管７１を用いて、それぞれ潤滑油（冷凍機油）を戻すことにより、上流の貯留部の冷凍機油が下流の貯留部へ移動してしまうのを避けることができる。
【００２３】
この形態の膨張機は膨張機構部が一つの１ＷＡＹ（一方向）の構成なので、図２（ｂ）に示す暖房運転時は膨張機１による動力回収を行なわない。図２（ｂ）において、膨張機１の圧縮機構部１０側の容器から四方弁９２へ接続するシェル吐出管２０に設けたバイパス弁９４を開いて、第１圧縮機９９から膨張機１に吸入された冷媒ガスが圧縮機構部１０で圧縮されずに素通りしてシェル吐出管２０から四方弁９２を介してガスクーラとなる室内機熱交換器９７を経て、室内機熱交換器９７と室外機熱交換器９８とを接続して膨張機１をバイパスする配管に設けた膨張弁９６で減圧されるように構成されている。膨張弁９６にて減圧された後の冷媒は蒸発器である室外機熱交換器９８で加熱後、四方弁９２，アキュムレータ９３を経て第１圧縮機９９へ戻る。
【００２４】
上述の暖房運転では膨張機１に内設の圧縮機構部１０では圧縮を行なわないので、第１圧縮機９９にて低圧（Ｐｌ）から高圧（Ｐｈ）までの圧縮を行ない、圧縮機構部１０側の密閉容器７内空間の圧力はＰｈとなる。そして、室外機熱交換器９８と膨張機１に内設の膨張機構部９側を接続する配管に膨張機１から室外機熱交換器９８への流れを止める逆止弁９５があるため、膨張機１の膨張機構部９側の密閉容器７内空間も高圧（Ｐｈ）状態となり、膨張機１内では差圧シールおよび油戻し共に機能せずその必要もなくなる。 膨張機１は圧縮機構部１０側の空間が油分離器として機能し、アキュムレータ９３と第１圧縮機９９を接続する配管へ毛細管７１で油戻しを行なうのは冷房運転時と同様である。
【００２５】
実施の形態２．
次にこの発明の実施の形態２について、図３、図４により説明する。図３は本発明に係る冷凍空調装置用の別の膨張機の断面図で、膨張機１に内設した圧縮機構部１０を低段側の第二圧縮機として用いることを想定している。 図において、密閉容器７の左側に膨張機構部９側、もう一方の右側に圧縮機構部１０側を配設し、それぞれを駆動軸６３で連結して回転動力を伝達する構成であり、図１と同一また相当部分は同一符号を付けている。膨張機１の密閉容器７の膨張機構部９側に貫通した吸入管１６により膨張機構部９に直接吸入された高圧の冷媒ガスは、固定スクロール１２と揺動スクロール１５よりなる膨張機構９で減圧され、膨張後の冷媒は密閉容器７内に固定された膨張側フレーム３３の膨張機構側の空間から吐出管１７により蒸発器へ排出される。
【００２６】
冷媒の膨張過程において回収された動力は駆動軸８、継手６５，駆動軸６３を介してロータリー圧縮方式の圧縮機構部１０側のローリングピストン２６に伝えられる。一方、吸入管１８から圧縮機構部１０に直接に流入した低圧の冷媒ガスは、圧縮機構部１０が回収動力で駆動されることにより、低段の圧縮を行なわれ密閉容器７内の圧縮機構部１０側の空間に吐出され、密閉容器７に貫通接続したシェル吐出管２０により第１圧縮機９９へ排出されるように構成されている。
【００２７】
上記のように構成された膨張機では密閉容器７内の空間が、膨張側フレーム３３の膨張機構部９側は低圧、圧縮機構部１０側は中間圧となり、シール部材６４が中間圧と低圧との間の差圧をシールすることになる。前述の如く膨張過程の回収動力は高低圧間の全圧縮動力に対して１／３以下なので、中間圧は低圧に近い中間圧となり、シールしなければならない差圧は小さくなるが、ガスクーラをはさんで状態量が異なっているので確実に分離しなければならないことも同様である。
【００２８】
この膨張機１における膨張機構部９側の空間と圧縮機構部１０側の空間の隔離に関しては、接触式のシール部材６４により確実にシールし、摺動ロスが過大とならないようにシール前後を中間圧と低圧として差圧を小さく抑えている。
【００２９】
このような構成の膨張機１を用いた冷凍空調装置の冷媒回路を図４に示す。図４（ａ）に示す冷房運転時では、低圧（Ｐｌ）の冷媒ガスは膨張機１の回収動力によって駆動される圧縮機構部１０で圧縮されて中間圧（Ｐｌ＋ΔＰ）まで昇圧された後、モータにより駆動される高圧シェルタイプの第１圧縮機９９に中間圧（Ｐｌ＋ΔＰ）で吸入してさらに圧縮昇圧後、高圧（Ｐｈ）状態で吐出され四方弁９２を経てガスクーラとなる室外機熱交換器９８に流入する。 ガスクーラで冷却された冷媒は、膨張機１の膨張機構部９で減圧する過程で動力回収され、圧縮機構部１０における圧縮動力を供給する。 膨張機構部９にて低圧（Ｐｌ）となった冷媒は蒸発器である室内機熱交換器９７で加熱蒸発され、四方弁９２からアキュムレータ９３を経て低段側である膨張機１の圧縮機構部１０に戻り、冷凍サイクルを形成する。
【００３０】
このとき、潤滑が必要な第１圧縮機９９と膨張機１の圧縮機構部１０および膨張機構部９の３ヶ所に潤滑油（冷凍機油）を保持するため、膨張側フレーム３３に設けられて密閉容器７内の膨張側空間と圧縮側空間を繋ぐ微小孔７０と第１圧縮機９９からの油戻し毛細管７２で貯留される潤滑油量をバランスさせる。膨張機１の圧縮機構部１０に関しては必要レベルの油持出しを許容し、吐出圧雰囲気の第１圧縮機９９で圧縮後のシェル内空間において冷媒から冷凍機油を分離することにより油循環率極小化を図ることができる。第１圧縮機９９のシェル内空間からアキュムレータ９３と膨張機１に内設された圧縮機構部１０を接続する配管へ毛細管７２を設けて冷凍機油を戻すことにより、上記圧縮機構部１０から第１圧縮機９９への冷凍機油の移動に対してバランスさせる。また、膨張機１に内設された膨張機構部９に必要な潤滑油は、微小孔７０により圧縮機構部側から約ΔＰの差圧により供給される。
【００３１】
この形態では、膨張機構部が一つの１ＷＡＹ膨張機の構成なので、図４（ｂ）に示す暖房運転時は膨張機１による動力回収を行なわない。アキュムレータ９３から第１圧縮機９９の吸入側へ導き膨張機１をバイパスする配管に設けたバイパス弁９４を開いて、アキュムレータ９３からの低圧冷媒は膨張機１に内設された圧縮機構部１０を経由せずに第１圧縮機９９に吸入して圧縮される。そして、圧縮後吐出された高圧の冷媒は、四方弁９２から室内機熱交換器９７のガスクーラを経て、室内機熱交換器９７と室外機熱交換器９８とを接続して膨張機１をバイパスする配管に設けた膨張弁９６にて減圧される。減圧後の冷媒は室外機熱交換器９８の蒸発器で加熱後、四方弁９２からアキュムレータ９３を経て第１圧縮機９９へ戻り、冷凍サイクルを形成する。
【００３２】
この暖房運転時においては、膨張機１の圧縮機構部１０では圧縮を行なわないので、密閉容器７内の圧縮機構部側の空間は圧力が低圧（Ｐｌ）のままで第１圧縮機９９にて低圧（Ｐｌ）から高圧（Ｐｈ）まで昇圧する圧縮を行なう。室内機熱交換器９７と膨張機１の膨張機構部９側を接続する配管に設けられ、室内機熱交換器９７から膨張機１への冷媒流れを阻止する逆止弁９５のため、密閉容器７内の膨張機構部９側の空間も低圧（Ｐｌ）状態となり、膨張機１内での差圧シールおよび油戻し共に必要がなくなる。冷房運転時と同様、第１圧縮機９９からの油戻し毛細管７２により、アキュムレータ９３と第１圧縮機９９吸入側間の配管へ油戻しを行なう。
【００３３】
以上の説明は、何れも冷房運転時用の膨張機１に内設した膨張機構９と流量マッチング用の膨張弁９６を備え、暖房運転時は逆止弁により膨張機１を経由せずに膨張弁９６にて減圧・膨張させるような形態に関するものであるが、それとは逆に暖房運転時のみ膨張動力回収を行ない、冷房運転時に膨張機をバイパスするような形態も同様に構成できる。
【００３４】
実施の形態３．
次に、本発明の実施の形態３について、図５を用いて説明する。
ここでは、図３と同様に構成することが可能な第２圧縮機部分の両側に冷房用および暖房用それぞれの膨張機構部を備えた、所謂２ＷＡＹ膨張機について説明する。この場合、膨張機に内設した圧縮機構部とその両側に配置した膨張機構部の駆動軸間の継手を一方向にのみ回転伝達可能なローラクラッチとし、片方の膨張機構部により圧縮機構部が駆動される時には、他方の膨張機構部に回転が伝達されないようにする。
【００３５】
図５は、２ＷＡＹ膨張機を用いた冷凍空調装置の冷媒回路図である。図５（ａ）に示す冷房運転時には、膨張機１に内設した第２圧縮機である圧縮機構部１０は冷房用膨張機構部９ａの回収動力によって駆動され、低圧（Ｐｌ）の冷媒ガスが圧縮昇圧されて中間圧（Ｐｌ＋ΔＰ）となってから、モータにより駆動される高圧シェルタイプの第１圧縮機９９に吸入される。この第１圧縮機９９にて高圧（Ｐｈ）まで圧縮された後、第１圧縮機から吐出した冷媒ガスは、四方弁９２を経てガスクーラとなる室外機熱交換器９８で冷却され、膨張機１の冷房用膨張機構部９ａで減圧そして動力回収され、冷房用膨張機構部９ａと駆動軸により連結された圧縮機構部１０における圧縮動力を供給する。冷房用膨張機構部９ａにて低圧（Ｐｌ）まで減圧された冷媒は、室内機熱交換器９７へ流入しそこで加熱され、四方弁９２からアキュムレータ９３を経て低段側に相当する２ＷＡＹタイプの膨張機１に内設された圧縮機構部１０に戻り、冷凍サイクルを形成する。
【００３６】
このとき、潤滑が必要な第１圧縮機９９と膨張機１に潤滑油（冷凍機油）を貯留し、膨張機１内の圧縮機構部１０と膨張機構部９ａ間に設けた微小孔（図示せず）と第１圧縮機９９からアキュムレータ９３と膨張機１の圧縮機構部１０入口側との接続配管に接続した油戻し毛細管７２で冷凍サイクル内に分布する潤滑油量をバランスさせる。膨張機１に内設された圧縮機構部１０について最小限の油持出しを許容し、吐出圧雰囲気の第１圧縮機９９内部で冷凍機油を含む冷媒から油分離するのは実施の形態２で述べた１ＷＡＹタイプの膨張機１での形態と同じである。第１圧縮機９９からアキュムレータ９３と圧縮機構部１０間の接続配管への毛細管７２での返油や、微小孔７０ａによる圧縮機構部１０側から膨張機構部９ａ側への差圧ΔＰによる給油についても同様である。
【００３７】
また、図５（ｂ）に示す暖房運転時は、四方弁９２及び冷房用膨張機構部９ａ出口側と室内機熱交換器９７の間に設けられ室内機熱交換器７２から冷房用膨張機構部９ａへの流れを閉塞する逆止弁９５ａ，暖房用膨張機構部９ｂ出口側と室外機熱交換器９８の間に設けられ室外機熱交換器９８から暖房用膨張機構部９ｂへの流れを閉塞する逆止弁９５ｂにより、室内機熱交換器９７のガスクーラで冷却された高圧（Ｐｈ）の冷媒は膨張機１の暖房用膨張機構部９ｂに流入し、動力回収しながら減圧された後、室外機熱交換器９８，四方弁９２，アキュムレータ９３を経て圧縮機構部１０で低段側圧縮、そして連続して第１圧縮機９９で高段側圧縮の二段圧縮される。このとき、膨張機１内部の圧縮機構部１０と膨張機構部９ｂ間の隔離部に設けた微小孔７０ｂにより膨張機構部９ｂ側へ差圧給油すると共に、第１圧縮機９９からの油戻し毛細管７２でアキュムレータ９３と圧縮機構部１０間への返油を行なう。
【００３８】
また、本発明の実施の形態１〜３に係るいずれの冷凍空調装置も、使用する冷媒として超臨界となる二酸化炭素を用いているので、オゾン層破壊や地球温暖化など地球環境への悪影響が小さい冷凍空調装置を得ることができる。
【００３９】
【発明の効果】
以上のように、この発明の冷凍空調装置によれば、電動機によって駆動される第１圧縮機と、第１圧縮機で圧縮された高圧の冷媒ガスを冷却するガスクーラと、ガスクーラによって冷却された冷媒ガスを減圧することにより動力を回収する膨張機構部と、膨張機構部により減圧された冷媒を加熱する蒸発器と、膨張機構部と同一の密閉容器に内設され膨張機構部の回収動力により駆動される第２圧縮機とを備え、第１圧縮機と第２圧縮機は冷媒配管により直列に接続されるとともに、密閉容器内の第２圧縮機が内設された空間は二段圧縮の中間圧力で満たされるように構成したので、圧縮機構部側と膨張機構部側を確実にシールしながら、シールに伴なう摺動損失を少なくすることができ、回収効率の良い高性能の超臨界サイクルによる冷凍空調装置を得ることができる。
【００４０】
また、第２圧縮機は第１圧縮機による圧縮後の冷媒を圧縮し、密閉容器内の膨張機構部が内設された空間は高圧雰囲気となるように構成したので、動力回収運転時のガスクーラ以外の熱交換器での油循環率が低い高効率の冷凍空調装置を得ることができる。
【００４１】
また、第１圧縮機は第２圧縮機による圧縮後の冷媒を圧縮し、密閉容器内の膨張機機構部が内設された空間は低圧雰囲気となるように構成したので、動力回収運転時の蒸発器以外の熱交換器での油循環率が低い高効率の冷凍空調装置を得ることができる。
【００４２】
また、冷媒として二酸化炭素を用いたので、地球環境への悪影響の小さい冷凍空調装置を得ることができる。
【図面の簡単な説明】
【図１】本発明の実施の形態１に係る膨張機を示す断面図である。
【図２】本発明の実施の形態１に係り図１の膨張機を用いた冷媒回路図である。
【図３】本発明の実施の形態２に係る膨張機を示す断面図である。
【図４】本発明の実施の形態２に係り図３の膨張機を用いた冷媒回路図である。
【図５】本発明の実施の形態３に係る冷媒回路図である。
【図６】従来の更に別の膨張機が用いられるサイクルの運転状態を示す説明図である。
【符号の説明】
１ 膨張機、 ７ 密閉容器、 ８ 駆動軸、 ９，９ａ，９ｂ 膨張機構部、 １０ 圧縮機構部、 １１ モータ、 １２ （膨張）シリンダ／固定スクロール、 １５ （膨張）ローリングピストン／揺動スクロール、 １６ （膨張）吸入管、 １７ （膨張）吐出管、 １８ （圧縮）吸入管、 １９ （圧縮）吐出管、 ２０ （シェル）吐出管、 ２１ （圧縮）固定スクロール、 ２３ （圧縮）揺動スクロール、 ２４ （圧縮）フレーム、 ２５ （圧縮）シリンダヘッド、 ２６ ローリングピストン、 ３３ （膨張）フレーム、 ６３ （圧縮）駆動軸、６４ シール部材、 ６５ 継手、 ７０，７０ａ，７０ｂ 微小孔、 ７１油戻し管、 ７２ 油戻し管、 ９２ 四方弁、 ９３ アキュムレータ、 ９４ バイパス弁、 ９５，９５ａ，９５ｂ 逆止弁、 ９６ 膨張弁、 ９７
室内機、 ９８ 室外機、９９ 第１圧縮機。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a refrigeration air conditioner using a refrigeration cycle using a supercritical refrigerant such as carbon dioxide.
[0002]
[Prior art]
In a conventional compressor with a built-in hermetic expander, an expansion mechanism 9 and a compression mechanism 10 that receive power transmission from each other by a single drive shaft 8 are housed in a hermetic container 7, and the compression mechanism 10 is driven by a motor 11. Then, the refrigerant gas sucked from the compression suction pipe 18 is compressed and discharged from the discharge port 19 into the closed container 7. Then, the refrigerant flowing out of the compression discharge pipe 20 provided at the upper part of the closed container and passing through the condenser of the refrigerant circuit is sucked from the expansion suction pipe 16, and decompressed and expanded in the expander cylinder 12 to expand and discharge the expansion discharge pipe 17. And returns to the compression suction pipe 18 through the evaporator of the refrigerant circuit. The power generated in the expansion process when the refrigerant passes through the expansion mechanism 9 is recovered as a part of the compression power on the compression mechanism 10 side via the drive shaft 8, and the output of the motor 11 is reduced. (For example, see Patent Document 1).
[0003]
In the second conventional compressor with a built-in expander, a compression mechanism 10 is provided at a lower portion of the closed casing 7 and an expansion mechanism 9 is provided at an upper portion, and a motor 11 is provided at a central portion therebetween. The lower end of the drive shaft 8 of the motor is connected to the compression mechanism 10, and the upper end is connected to the expansion mechanism 9. Refrigerant is sucked from an expansion suction pipe 16 provided in the upper portion of the closed container, expanded in the scroll-type expansion mechanism 9, and recovered from the expansion process of the refrigerant discharged from the expansion discharge pipe 17 by the drive shaft 8. (See, for example, Patent Document 2).
[0004]
Further, as a third conventional example, in a compressor with a built-in expander for a Rankine cycle drive air conditioning system, an expansion mechanism 9 is arranged on the right side in a closed container 7 and a compression mechanism 10 is arranged on the left side in a closed vessel 7 to constitute a refrigeration cycle. This is a one-fluid system in which the discharge gas from the compression mechanism 10 and the discharge gas from the expansion mechanism 9 constituting the Rankine cycle are discharged to the closed container case 7. The high-pressure refrigerant gas on the Rankine cycle side sucked from the expansion suction pipe 16 is decompressed by the expansion mechanism 9 and then discharged into the closed container 7. The expansion power recovered in the process of decompression drives the compression mechanism 10 via the drive shaft 8, the joint 65, and the drive shaft 63 of the compression mechanism, and the low-pressure refrigerant gas on the refrigeration cycle side sucked from the compression suction pipe 18. Compress. Then, the compressed refrigerant gas merges with the refrigerant gas expanded in the expansion mechanism section 9 in the closed vessel 7, and is branched from the discharge pipe 17 to the circuits on the Rankine cycle side and the refrigeration cycle side. (For example, see Patent Document 3).
[0005]
[Patent Document 1]
JP-A-59-25097 (page 2, FIG. 7)
[Patent Document 2]
JP 2001-107881A (Page 3-4, FIG. 1)
[Patent Document 3]
JP-A-9-250474 (page 2-3, FIG. 1)
[0006]
[Problems to be solved by the invention]
In the third conventional example, the expansion mechanism 9 is used in the expansion process of the Rankine cycle shown in FIG. 6, and the compression mechanism 10 is used in the compression process of the refrigeration cycle shown in FIG. Since it corresponds to a so-called one-fluid system in which the state quantities are the same, the inside of the sealed container 7 can be used as one space. FIG. 6 is a Mollier diagram with pressure on the vertical axis and enthalpy on the horizontal axis, showing each process of compression, condensation, expansion and evaporation.
[0007]
On the other hand, when the power recovered in the expansion process in the refrigeration cycle instead of the Rankine cycle is used as part of the compression power in the compression process, both high pressure is used after compression and before expansion, or low pressure is used both after expansion and before compression. However, since they have different state quantities, they cannot be used as a single fluid in a closed container.
[0008]
Further, in the above-mentioned second conventional example, the inside of the sealed container is in a low-pressure atmosphere where the expansion mechanism side space discharges the expander, and the high pressure atmosphere is where the side where the motor and the compression mechanism section discharge the compressor is high. Has become. For this reason, an axial force due to the differential pressure acts on the drive shaft that penetrates the frame holding the expansion mechanism, and seals high and low pressures through minute clearances in the bearing.
[0009]
Further, in the first conventional example described above, the inside of the closed container is in the discharge pressure atmosphere of the compression mechanism portion, and no axial force acts on the drive shaft. It is necessary to seal high and low pressure even to a small gap.
[0010]
Furthermore, the situation in which the inside of a closed vessel must be sealed at high and low pressures up to the minute clearance of the moving parts of the compression mechanism section is the same as in a normal rolling piston type refrigerant compressor, but it is similar to a supercritical fluid such as carbon dioxide. In the case of a working refrigerant, the differential pressure increases, so that in the case of a compressor, it is necessary to take measures to reduce the differential pressure, for example, to make the inside of the closed vessel an intermediate pressure atmosphere by two-stage compression.
[0011]
As described above, in an expander that recovers power from the expansion process of the refrigeration cycle and uses it as part of the power in the compression process, transmission of power by a drive shaft or the like between the expansion mechanism and the compression mechanism is performed. In doing so, spaces having different working refrigerant pressures or state quantities must be isolated.
[0012]
SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and in an expander in which an expansion mechanism section and a compression mechanism section are housed in a single hermetic container, sliding by sealing a differential pressure between the expansion side and the compression side. An object of the present invention is to provide a refrigeration / air-conditioning apparatus using a compressor with a built-in expander that reliably separates an expansion mechanism and a compression mechanism while suppressing loss such as movement.
[0013]
[Means for Solving the Problems]
A refrigeration / air-conditioning apparatus according to the present invention is configured such that a first compressor driven by an electric motor, a gas cooler for cooling high-pressure refrigerant gas compressed by the first compressor, and a refrigerant gas cooled by the gas cooler are depressurized. An expansion mechanism for recovering power, an evaporator for heating the refrigerant decompressed by the expansion mechanism, and a second compressor provided in the same closed container as the expansion mechanism and driven by the recovery power of the expansion mechanism The first compressor and the second compressor are connected in series by a refrigerant pipe, and the space in which the second compressor is provided in the closed vessel is filled with the intermediate pressure of the two-stage compression. It is composed.
[0014]
The second compressor compresses the refrigerant after compression by the first compressor, and the space in which the expansion mechanism in the closed container is provided has a high-pressure atmosphere.
[0015]
The first compressor compresses the refrigerant compressed by the second compressor, and the space in which the expander mechanism is provided in the closed vessel has a low-pressure atmosphere.
[0016]
Further, carbon dioxide is used as a refrigerant.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
Hereinafter, Embodiment 1 of the present invention will be described. FIG. 1 is a cross-sectional view of an expander capable of recovering power used in a refrigeration / air-conditioning apparatus according to the present invention. Is used. The expander 1 shown in FIG. 1 has an expansion mechanism 9 on the left side inside a sealed container 7 and a compression mechanism 10 serving as a second compressor on the other right side, which are connected by a drive shaft 63 and rotated. It is configured to transmit power. In the drawing, the high-pressure refrigerant gas sucked from the expansion suction pipe 16 into the space inside the closed casing 7 on the side of the expansion mechanism 9 fixed to the expansion frame 33 in the closed casing 7 is supplied to the fixed scroll 12 and the oscillating scroll 15. The refrigerant after being decompressed and expanded by the expansion mechanism 9 is directly discharged from the expansion discharge pipe 17 to the evaporator.
[0018]
The power recovered in the expansion process of the refrigerant is supplied to the expansion-side drive shaft 8 fixed to the orbiting scroll 15 on the expansion mechanism 9 side, and a joint 65 for transmitting the rotation of the expansion-side drive shaft 8 to the compression-side drive shaft 63. Is transmitted to the orbiting scroll 23 on the compression mechanism 10 side fixed to the compression side frame 24 via the compression side drive shaft 63. After being compressed by a first compressor 99, which will be described later, connected by a refrigerant pipe, it is between a high-pressure condensation and a low-pressure evaporation flowing into a closed container from a compression suction pipe 18 provided on a compression mechanism side of the closed container 7. The intermediate-pressure refrigerant gas is subjected to a high-stage compression stroke by the reciprocal operation of the orbiting scroll 23 and the fixed scroll 12 on the compression side by the recovered power in the expansion process of the expansion mechanism 9. The gas is directly discharged from the compression discharge pipe 20 to the gas cooler without flowing out into the closed container 7.
[0019]
In the expander configured as described above, the space in one closed container 7 is in a state of high-pressure refrigerant on the side of the expansion mechanism 9 having the expansion-side frame 33, while the space is compressed from the joint 65 and the compression-side drive shaft 63. The mechanism section 10 is in the state of intermediate-pressure refrigerant, and the seal member 64 provided on the bearing holding section of the expansion-side drive shaft 8 in the expansion-side frame 33 seals the differential pressure between high pressure and intermediate pressure. Since the recovered power in the expansion process is not large (1/3 or less) as a percentage of the total compression power between the high and low pressures of the working refrigerant between the gas cooler and the evaporator, the intermediate pressure in this two-stage compression is an intermediate pressure close to the high pressure. The differential pressure required to seal between the expansion mechanism side and the compression mechanism side in the sealed container 7 is reduced. However, during the process of passing through the gas cooler and flowing into the expansion suction pipe 16 after discharging from the compression discharge pipe 20 as described above, the refrigerant changes from the superheated gas to a liquid in the supercooled region or a supercritical state before and after this gas cooler. And the state quantity is different, so that the refrigerant must be surely separated.
[0020]
Concerning the separation of the space inside the container on the side of the expansion mechanism 9 and the space inside the container on the side of the compression mechanism 10, as in the second conventional example described above, a method of sealing with a slide bearing clearance between the drive shaft and the frame may be considered. However, in the case of non-contact seals, some leakage must be allowed. On the other hand, in the embodiment shown in FIG. 1, it is possible to reliably seal with the contact-type sealing member 64 between the expansion-side frame 33 and the expansion-side drive shaft 8, but a sliding loss occurs. It is necessary to reduce the differential pressure for sealing as much as possible, and in the expander capable of recovering power according to the present invention, the high pressure and the intermediate pressure are set before and after the seal, so that the compression mechanism side and the expansion mechanism side And the sliding loss associated with this seal can be reduced, and a refrigeration / air-conditioning apparatus using a supercritical cycle using a high-performance CO2 refrigerant with high power recovery efficiency can be obtained.
[0021]
FIG. 2 shows a refrigerant circuit of a refrigeration / air-conditioning apparatus using an expander having such a configuration. FIG. 2A shows a cooling operation in which a refrigerant of supercritical carbon dioxide is used, and a low-pressure (P1) refrigerant is compressed by a first compressor 99 on a low-stage side driven by a motor to have an intermediate pressure (P1). (Ph−ΔP), and then sucked and compressed by the compression mechanism 10 on the higher stage inside the expander 1 that is connected in series with the first compressor 99 by piping. Through the valve 92, the heat reaches an outdoor unit heat exchanger 98 serving as a gas cooler which performs a condensation process. The refrigerant cooled by the gas cooler is recovered in the process of reducing pressure in the expansion mechanism 9 of the expander 1, and supplies gas compression power in the compression mechanism 10. The refrigerant that has been reduced in pressure by the expansion mechanism 9 to a low pressure (Pl) is heated in the indoor unit heat exchanger 97 serving as an evaporator, and then passes through the four-way valve 92 and the accumulator 93 again to the low-stage first. Returning to the compressor 99, a refrigeration cycle is formed.
[0022]
At this time, it does not matter whether the type of the first compressor 99 (scroll compression, rotary compression, or the like) and the pressure inside the sealed container is the suction pressure or the discharge pressure. The space inside the sealed container 7 in the compression mechanism unit 10 inside the expander 1 serving as a compressor is an intermediate pressure atmosphere (Ph-Δ) on the discharge side of the first compressor 99. The lubricating oil is held at three places of the first compressor 99 and the expander 1 which require lubrication, ie, the compression mechanism 10 and the expansion mechanism 9 provided in the expander 1, and is provided on the expansion-side frame 33 shown in FIG. The amount of the lubricating oil stored in the closed container 7 is balanced by the minute holes 70 connecting the expansion side space and the compression side space inside and the oil return capillary tube 71. The first compressor 99 and the compression mechanism 10 provided in the expander 1 allow a required level of oil take-out, and the oil circulation rate can be minimized in the space at the entrance of the expansion mechanism 9. Using an oil return capillary 71 from the expansion mechanism 9 to the compression mechanism 10 via the micro holes 70 and from the compression mechanism 10 to the refrigerant pipe between the accumulator 93 and the first compressor 99, lubricating oil ( By returning the refrigerating machine oil), the refrigerating machine oil in the upstream storage unit can be prevented from moving to the downstream storage unit.
[0023]
Since the expander of this embodiment has a one-way (one-way) expansion mechanism, the power recovery by the expander 1 is not performed during the heating operation shown in FIG. In FIG. 2B, the bypass valve 94 provided in the shell discharge pipe 20 connected to the four-way valve 92 from the container on the compression mechanism 10 side of the expander 1 is opened, and the first compressor 99 sucks into the expander 1. The refrigerant gas passed through without being compressed by the compression mechanism section 10 passes through the indoor unit heat exchanger 97 serving as a gas cooler from the shell discharge pipe 20 via the four-way valve 92, and the indoor unit heat exchanger 97 and the outdoor unit heat The pressure is reduced by an expansion valve 96 provided in a pipe connecting the exchanger 98 and bypassing the expander 1. The refrigerant after being decompressed by the expansion valve 96 is heated by the outdoor unit heat exchanger 98 as an evaporator, and then returns to the first compressor 99 via the four-way valve 92 and the accumulator 93.
[0024]
In the above-mentioned heating operation, since the compression mechanism 10 provided inside the expander 1 does not perform compression, the first compressor 99 performs compression from low pressure (Pl) to high pressure (Ph), and the compression mechanism 10 side. The pressure in the space inside the closed container 7 becomes Ph. Since there is a check valve 95 for stopping the flow from the expander 1 to the outdoor unit heat exchanger 98 in a pipe connecting the outdoor unit heat exchanger 98 and the expansion mechanism 9 provided inside the expander 1, the expansion is performed. The space inside the sealed container 7 on the side of the expansion mechanism 9 of the machine 1 is also in a high-pressure (Ph) state, and the differential pressure seal and the oil return do not function nor need in the expander 1. In the expander 1, the space on the side of the compression mechanism 10 functions as an oil separator, and the oil is returned to the pipe connecting the accumulator 93 and the first compressor 99 by the capillary 71 in the same manner as in the cooling operation.
[0025]
Embodiment 2 FIG.
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a cross-sectional view of another expander for a refrigeration / air-conditioning apparatus according to the present invention. It is assumed that the compression mechanism 10 provided inside the expander 1 is used as a second compressor on the lower stage. In the figure, the expansion mechanism 9 side is provided on the left side of the sealed container 7 and the compression mechanism section 10 side is provided on the other right side, and each is connected by a drive shaft 63 to transmit rotational power. The same or corresponding parts are denoted by the same reference numerals. The high-pressure refrigerant gas directly sucked into the expansion mechanism 9 by the suction pipe 16 penetrating the expansion mechanism 9 of the closed casing 7 of the expander 1 is decompressed by the expansion mechanism 9 including the fixed scroll 12 and the orbiting scroll 15. The expanded refrigerant is discharged from the space on the expansion mechanism side of the expansion-side frame 33 fixed in the closed container 7 to the evaporator by the discharge pipe 17.
[0026]
The power recovered in the expansion process of the refrigerant is transmitted to the rolling piston 26 on the side of the rotary compression type compression mechanism 10 via the drive shaft 8, the joint 65, and the drive shaft 63. On the other hand, the low-pressure refrigerant gas that has flowed directly from the suction pipe 18 into the compression mechanism 10 is compressed at a low stage by the compression mechanism 10 being driven by the recovery power, so that the compression mechanism in the closed container 7 is compressed. It is configured to be discharged to the space on the side of the 10 and discharged to the first compressor 99 by a shell discharge pipe 20 penetratingly connected to the closed container 7.
[0027]
In the expander configured as described above, the space in the sealed container 7 is such that the expansion mechanism section 9 side of the expansion side frame 33 has a low pressure, the compression mechanism section 10 has an intermediate pressure, and the seal member 64 has an intermediate pressure and a low pressure. To seal the pressure difference between the two. As described above, the recovery power in the expansion process is 1/3 or less of the total compression power between high and low pressures. Therefore, the intermediate pressure becomes an intermediate pressure close to low pressure, and the differential pressure that must be sealed becomes small. The same is true of the fact that the state quantities are different and must be reliably separated.
[0028]
Regarding the separation of the space on the side of the expansion mechanism 9 and the space on the side of the compression mechanism 10 in the expander 1, the contact-type seal member 64 is used to reliably seal the space between the seals before and after the seal so that the sliding loss is not excessive. The differential pressure is kept small as pressure and low pressure.
[0029]
FIG. 4 shows a refrigerant circuit of a refrigeration air conditioner using the expander 1 having such a configuration. In the cooling operation shown in FIG. 4A, the low-pressure (Pl) refrigerant gas is compressed by the compression mechanism 10 driven by the recovery power of the expander 1, and after being boosted to the intermediate pressure (Pl + ΔP), An outdoor unit heat exchanger 98 which is sucked at an intermediate pressure (Pl + ΔP) into a first compressor 99 of a high-pressure shell driven by a compressor, further compressed and pressurized, discharged in a high-pressure (Ph) state, passes through a four-way valve 92 and becomes a gas cooler 98. Flows into. The refrigerant cooled by the gas cooler is recovered in the process of being decompressed by the expansion mechanism 9 of the expander 1, and supplies compression power in the compression mechanism 10. The refrigerant which has become low pressure (Pl) in the expansion mechanism 9 is heated and evaporated in the indoor unit heat exchanger 97 as an evaporator, passes through the four-way valve 92 via the accumulator 93, and the compression mechanism of the expander 1 on the lower stage. Returning to 10, a refrigeration cycle is formed.
[0030]
At this time, in order to hold lubricating oil (refrigerating machine oil) in three places of the first compressor 99 and the compression mechanism section 10 and the expansion mechanism section 9 of the expander 1 which require lubrication, the lubricating oil is provided on the expansion side frame 33 and hermetically sealed. The amount of lubricating oil stored in the micro holes 70 connecting the expansion side space and the compression side space in the container 7 and the oil return capillary tube 72 from the first compressor 99 is balanced. With respect to the compression mechanism section 10 of the expander 1, the required level of oil can be taken out, and the refrigerating machine oil is minimized by separating the refrigerating machine oil from the refrigerant in the space in the shell after compression by the first compressor 99 in the discharge pressure atmosphere. Can be achieved. By providing a capillary tube 72 from the inner space of the shell of the first compressor 99 to the pipe connecting the accumulator 93 and the compression mechanism unit 10 provided in the expander 1, and returning the refrigerating machine oil, the first compression mechanism unit 10 The movement of the refrigerating machine oil to the compressor 99 is balanced. Further, the lubricating oil required for the expansion mechanism section 9 provided inside the expander 1 is supplied from the compression mechanism section side by a small pressure difference pressure of about ΔP.
[0031]
In this embodiment, since the expansion mechanism is configured as one 1-way expander, power recovery by the expander 1 is not performed during the heating operation shown in FIG. By opening the bypass valve 94 provided in the pipe that leads from the accumulator 93 to the suction side of the first compressor 99 and bypasses the expander 1, the low-pressure refrigerant from the accumulator 93 passes through the compression mechanism 10 provided in the expander 1. It is sucked into the first compressor 99 and compressed without passing through. The high-pressure refrigerant discharged after compression passes through the gas cooler of the indoor unit heat exchanger 97 from the four-way valve 92, connects the indoor unit heat exchanger 97 and the outdoor unit heat exchanger 98, and bypasses the expander 1. The pressure is reduced by an expansion valve 96 provided in the piping. After the depressurized refrigerant is heated by the evaporator of the outdoor unit heat exchanger 98, the refrigerant returns from the four-way valve 92 to the first compressor 99 via the accumulator 93 to form a refrigeration cycle.
[0032]
During the heating operation, since the compression mechanism 10 of the expander 1 does not perform compression, the space on the compression mechanism side in the sealed container 7 remains at a low pressure (Pl) by the first compressor 99. Compression is performed to increase the pressure from low pressure (Pl) to high pressure (Ph). A sealed container for a check valve 95 provided on a pipe connecting the indoor unit heat exchanger 97 and the expansion mechanism 9 side of the expander 1 to prevent a refrigerant flow from the indoor unit heat exchanger 97 to the expander 1 The space on the side of the expansion mechanism 9 inside the expansion unit 7 is also in a low pressure (Pl) state, and there is no need for both the differential pressure seal and the oil return in the expansion machine 1. As in the cooling operation, the oil is returned to the pipe between the accumulator 93 and the suction side of the first compressor 99 by the oil return capillary tube 72 from the first compressor 99.
[0033]
Each of the above descriptions includes the expansion mechanism 9 provided inside the expansion unit 1 for the cooling operation and the expansion valve 96 for the flow rate matching. In the heating operation, the expansion valve 9 is expanded without passing through the expansion unit 1 by the check valve. Although this embodiment relates to a mode in which the pressure is reduced and expanded by the valve 96, a mode in which the expansion power is recovered only during the heating operation and the expander is bypassed during the cooling operation can be similarly configured.
[0034]
Embodiment 3 FIG.
Next, a third embodiment of the present invention will be described with reference to FIG.
Here, a so-called 2WAY expander will be described in which expansion mechanisms for cooling and heating are provided on both sides of a second compressor portion that can be configured in the same manner as in FIG. In this case, the joint between the compression mechanism provided inside the expander and the drive shafts of the expansion mechanisms disposed on both sides thereof is a roller clutch capable of transmitting rotation in only one direction, and the compression mechanism is controlled by one of the expansion mechanisms. When driven, rotation is prevented from being transmitted to the other expansion mechanism.
[0035]
FIG. 5 is a refrigerant circuit diagram of a refrigeration / air-conditioning apparatus using a 2-way expander. During the cooling operation shown in FIG. 5A, the compression mechanism unit 10 as the second compressor provided in the expander 1 is driven by the recovery power of the cooling expansion mechanism unit 9a, and the low-pressure (Pl) refrigerant gas is discharged. After being compressed and raised to an intermediate pressure (Pl + ΔP), it is sucked into a high-pressure shell-type first compressor 99 driven by a motor. After being compressed to a high pressure (Ph) by the first compressor 99, the refrigerant gas discharged from the first compressor is cooled by an outdoor unit heat exchanger 98 serving as a gas cooler via a four-way valve 92, and The pressure is reduced and the power is recovered by the cooling expansion mechanism 9a, and the compression power is supplied to the compression mechanism 10 connected to the cooling expansion mechanism 9a by a drive shaft. The refrigerant decompressed to a low pressure (Pl) by the cooling expansion mechanism 9a flows into the indoor unit heat exchanger 97, is heated there, passes through the four-way valve 92, passes through the accumulator 93, and is a 2-way type expansion corresponding to the lower stage. Returning to the compression mechanism section 10 provided inside the machine 1, a refrigeration cycle is formed.
[0036]
At this time, lubricating oil (refrigerating machine oil) is stored in the first compressor 99 and the expander 1 that require lubrication, and micro holes (not shown) provided in the expander 1 between the compression mechanism 10 and the expansion mechanism 9a. And the oil return capillary 72 connected to the connection pipe from the first compressor 99 to the accumulator 93 and the inlet of the compression mechanism 10 of the expander 1 to balance the amount of lubricating oil distributed in the refrigeration cycle. As described in the second embodiment, the compression mechanism unit 10 provided inside the expander 1 allows a minimum amount of oil to be taken out, and oil is separated from the refrigerant including the refrigerating machine oil inside the first compressor 99 in the discharge pressure atmosphere. The configuration is the same as that of the 1-way type expander 1 described above. Oil return from the first compressor 99 to the connection pipe between the accumulator 93 and the compression mechanism unit 10 by the capillary tube 72 and oil supply by the differential pressure ΔP from the compression mechanism unit 10 side to the expansion mechanism unit 9a side by the micro holes 70a. The same is true for
[0037]
In the heating operation shown in FIG. 5B, the cooling mechanism is provided between the four-way valve 92 and the outlet side of the cooling expansion mechanism 9 a and the indoor unit heat exchanger 97. A check valve 95a for blocking the flow to 9a, and provided between the outlet side of the heating expansion mechanism 9b and the outdoor unit heat exchanger 98 to block the flow from the outdoor unit heat exchanger 98 to the heating expansion mechanism 9b. The high-pressure (Ph) refrigerant cooled by the gas cooler of the indoor unit heat exchanger 97 flows into the heating expansion mechanism 9b of the expander 1 by the check valve 95b, and is decompressed while recovering power. Through the heat exchanger 98, the four-way valve 92, and the accumulator 93, the compression mechanism section 10 performs low-stage compression, and successively performs first-compressor two-stage compression using the first compressor 99. At this time, the differential pressure oil supply to the expansion mechanism 9b side is performed by the minute holes 70b provided in the separation portion between the compression mechanism 10 and the expansion mechanism 9b inside the expander 1, and the oil return capillary from the first compressor 99 is supplied. At 72, oil return between the accumulator 93 and the compression mechanism 10 is performed.
[0038]
In addition, any of the refrigerating and air-conditioning apparatuses according to Embodiments 1 to 3 of the present invention uses supercritical carbon dioxide as a refrigerant to be used, so that adverse effects on the global environment such as ozone depletion and global warming are reduced. A small refrigeration air conditioner can be obtained.
[0039]
【The invention's effect】
As described above, according to the refrigeration / air-conditioning apparatus of the present invention, the first compressor driven by the electric motor, the gas cooler for cooling the high-pressure refrigerant gas compressed by the first compressor, and the refrigerant cooled by the gas cooler An expansion mechanism that recovers power by reducing the pressure of the gas, an evaporator that heats the refrigerant decompressed by the expansion mechanism, and an expansion mechanism that is installed in the same closed container as the expansion mechanism and is driven by the recovery power of the expansion mechanism The first compressor and the second compressor are connected in series by a refrigerant pipe, and the space in the closed vessel where the second compressor is provided is an intermediate space between the two-stage compression. The structure is designed to be filled with pressure, so that the compression mechanism and expansion mechanism can be reliably sealed, and sliding loss associated with the seal can be reduced. Refrigeration by cycle It is possible to obtain a control apparatus.
[0040]
Further, the second compressor compresses the refrigerant after compression by the first compressor, and the space in which the expansion mechanism in the closed vessel is provided has a high-pressure atmosphere. A high-efficiency refrigeration and air-conditioning system having a low oil circulation rate in other heat exchangers can be obtained.
[0041]
In addition, the first compressor compresses the refrigerant after compression by the second compressor, and the space in which the expander mechanism in the closed vessel is provided has a low-pressure atmosphere. A high-efficiency refrigeration / air-conditioning device having a low oil circulation rate in a heat exchanger other than the evaporator can be obtained.
[0042]
Further, since carbon dioxide is used as the refrigerant, a refrigeration / air-conditioning apparatus having a small adverse effect on the global environment can be obtained.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an expander according to Embodiment 1 of the present invention.
FIG. 2 is a refrigerant circuit diagram using the expander of FIG. 1 according to the first embodiment of the present invention.
FIG. 3 is a sectional view showing an expander according to Embodiment 2 of the present invention.
FIG. 4 is a refrigerant circuit diagram using the expander of FIG. 3 according to the second embodiment of the present invention.
FIG. 5 is a refrigerant circuit diagram according to Embodiment 3 of the present invention.
FIG. 6 is an explanatory diagram showing an operating state of a cycle in which another conventional expander is used.
[Explanation of symbols]
Reference Signs List 1 expander, 7 sealed container, 8 drive shaft, 9, 9a, 9b expansion mechanism, 10 compression mechanism, 11 motor, 12 (expansion) cylinder / fixed scroll, 15 (expansion) rolling piston / oscillating scroll, 16 (Expansion) suction pipe, 17 (expansion) discharge pipe, 18 (compression) suction pipe, 19 (compression) discharge pipe, 20 (shell) discharge pipe, 21 (compression) fixed scroll, 23 (compression) oscillating scroll, 24 (Compression) frame, 25 (compression) cylinder head, 26 rolling piston, 33 (expansion) frame, 63 (compression) drive shaft, 64 seal member, 65 joint, 70, 70a, 70b micro hole, 71 oil return pipe, 72 Oil return pipe, 92 four-way valve, 93 accumulator, 94 bypass valve, 95, 95a, 95b check valve, 96 expansion valve, 97
Indoor unit, 98 outdoor unit, 99 first compressor.
