JP3738760B2

JP3738760B2 - Refrigeration equipment

Info

Publication number: JP3738760B2
Application number: JP2002374387A
Authority: JP
Inventors: 章藤高; 寿夫若林; 伸二渡辺; 浩直沼本; 幸男渡邊; 完爾羽根田; 義典小林; 雄一薬丸; 成人山口
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2002-12-25
Filing date: 2002-12-25
Publication date: 2006-01-25
Anticipated expiration: 2015-12-21
Also published as: JP2003207237A

Description

【０００１】
【発明の属する技術分野】
本発明は、非共沸混合冷媒を用いた冷凍装置に関するものである。
【０００２】
【従来の技術】
近年、ＣＦＣおよびＨＣＦＣフロンの規制にともない冷凍装置の代替冷媒として混合冷媒が注目をあびている。従来の非共沸混合冷媒を用いた冷凍装置の一例について、以下図面を参照しながら説明する。
【０００３】
図２１は従来の非共沸混合冷媒を用いた冷凍装置の冷凍サイクルを示すものである。
【０００４】
図２１において５０は圧縮機、５１は四方弁、５２は室内熱交換器、５３は絞り装置、５４は室外熱交換器で、順次環状に接続されて主回路を構成している。
【０００５】
以上のように構成された冷凍装置について、以下その動作について説明する。
【０００６】
圧縮機５０で圧縮された高温高圧の冷媒蒸気は、四方弁５１を介して室内熱交換器５２において放熱し、凝縮液化する。その後、絞り装置５３で減圧膨張されて低温低圧の冷媒となる。そして、室外熱交換器５４で吸熱して蒸発、気化した後、低温低圧の冷媒蒸気となり、再び圧縮機５０で圧縮され冷凍サイクルを繰り返す（例えば特開平３−１３７６６号公報）。
【０００７】
【発明が解決しようとする課題】
暖房運転時の室外熱交換器は蒸発器として作用し、冷媒は気液二相状態で変化する。単一冷媒の場合は熱交換器の入口冷媒温度と出口冷媒温度は同じであるが、非共沸混合冷媒は非等温性があり、冷媒の乾き度が大きくなるに従い温度が高くなるため室外熱交換器入口冷媒温度の方が室外熱交換器出口冷媒温度よりも低くなる。そのため上記のような構成では、暖房運転時、単一冷媒の場合では室外熱交換器に着霜しないような室外温度でも、非共沸混合冷媒を用いると室外熱交換器の入口に着霜し、暖房能力が低下することが考えられる。
【０００８】
本発明は上記従来例の課題を解決するもので、室外熱交換器の部分的な着霜を防ぎ効率の良い暖房運転を可能とすることを目的としたものである。
【０００９】
【課題を解決するための手段】
上記問題点を解決するために本発明は、非共沸混合冷媒を用い、圧縮機、四方弁、室内熱交換器、絞り装置、第１室外熱交換器、制御弁、第２室外熱交換器を環状に接続し、前記第１室外熱交換器より前記第２室外熱交換器の大きさを大きくするとともに、前記制御弁と並列に設けた第２絞り装置を備え、前記制御弁の開閉動作を行う設定温度は、第１設定温度、第２設定温度、第３設定温度となるに従い値は小さく設定されており、前記第１室外熱交換器の冷媒温度が前記第３設定温度より低い時は前記制御弁を開き、前記第３設定温度以上で前記第２設定温度より低い時は前記制御弁を閉じ、前記第１設定温度以上の時は前記制御弁を開く構成としたことを特徴とする冷凍装置である。上記制御弁と並列に設けられた第２絞り装置によって、第１室外熱交換器が着霜を起こすような温度条件下において、制御弁が動作すると、冷媒は第２絞り装置に流れ、第２絞り装置の前後で冷媒に差圧が生じ、第１室外熱交換器の圧力は第２室外熱交換器の圧力より高くなり第１室外熱交換器を流れる冷媒の温度は高くなるため、第１熱交換器入口の着霜を防ぐことができ、
効率の良い暖房運転を可能にできる。
【００１０】
【発明の実施の形態】
上記の課題を解決するための本発明は、制御弁、前記制御弁と並列に第２絞り装置を設けたものである。このことにより、第１室外熱交換器が着霜を起こすような温度条件下において、制御弁が動作すると、冷媒は第２絞り装置に流れ、第２絞り装置の前後で冷媒に差圧が生じ、第１室外熱交換器の圧力は第２室外熱交換器の圧力より高くなり第１室外熱交換器を流れる冷媒の温度は高くなるため、第１熱交換器入口の着霜を防ぐことができ、効率の良い暖房運転を可能にできる。
【００１１】
また、本発明は、第１室外熱交換器、第２室外熱交換器の間に減圧機構を有し形状記憶合金バネを内蔵した制御弁を設けることで、室外熱交換器が着霜を起こすような条件下において形状記憶合金バネが変態しバイアスバネにより押されてたわみ、弁体を弁座に押しつけ冷媒の流路を狭めると、冷媒は制御弁の前後で差圧が生じ、第１室外熱交換器の圧力は第２室外熱交換器の圧力より高くなり第１室外熱交換器を流れる冷媒の温度は高くなるため、第１熱交換器入口の着霜を防ぐことができ、別の絞り装置、弁制御装置が不要で、より簡単な構成で効率の良い暖房運転を可能にできる。
【００１２】
【実施例】
以下、本発明の実施例について、図面を参照して説明する。
【００１３】
（実施例１）
図１は、本発明の冷凍装置の第１の実施例における冷凍サイクル図である。
【００１４】
図１において、１は圧縮機、２は四方弁、３は室内熱交換器、４は絞り装置、５は第１室外熱交換器、６は制御弁、７は第２室外熱交換器で、順次環状に接続されて主回路を構成し、制御弁６と並列に第２絞り装置８を設け冷凍サイクルを構成し、第２室外熱交換器７の大きさは第１室外熱交換器５より大きい。２２は制御弁６の開閉を制御する弁制御装置、２４は第１室外熱交換器５の冷媒温度を検出して温度検出信号を出力する冷媒温度検出器である。
【００１５】
図２は図１に示す冷凍装置の電気接続を示す電気回路図である。図中、２４は第１室外熱交換器５の冷媒温度を検知するための冷媒温度検出器、２５はＡ／Ｄ変換装置、２６はマイクロコンピュータ（以下ＬＳＩと称す）であり、入力回路２７、ＣＰＵ２８、メモリ２９、出力回路３０を有している。入力回路２７には、第１室外熱交換器５の冷媒温度検出器２４の出力が、Ａ／Ｄ変換装置２５を介して入力される。３１は電磁コイルで、出力回路３０の出力により制御弁６の開閉を動作させる。
【００１６】
ここで図３に示すブロック図と図２に示す電気回路図について説明すると、図２の第１室外熱交換器５の冷媒温度検出器２４は、図３の第１室外熱交換器５の冷媒温度を検出して出力する冷媒温度検出手段、図２のＬＳＩ２６は、図３の冷媒温度検出手段により検出された値と設定値とを比較し制御信号を出力する比較手段と、制御弁６の開閉を制御する出力モードを記憶した記憶手段と、比較手段から発生する出力信号により、前記記憶手段の出力モードの一つを選択する選択手段に相当する。そして、図２の制御弁６を開閉させる電磁コイル３１は、図３の出力手段に相当する。
【００１７】
上記構成において、冷凍装置運転時の制御回路の構成と動作を図４を参考に説明する。図４はＬＳＩ２６のメモリ２９に記憶された冷凍装置のプログラムを示すフローチャートである。
【００１８】
運転の指示が出ると、冷凍装置の運転が始まり、同時に図４に示すステップ４０が実行され第１室外熱交換器５の冷媒温度Ｔ_eが検出され、ステップ４１で第１室外熱交換器５の冷媒温度Ｔ_eと第２設定温度Ｔ₂（例えば−２℃）との比較演算を行い、Ｔ_e≧Ｔ₂であれば「ＮＯ」の判定によりステップ４２に進みメモリ２９内蔵の選択手段により記憶回路の第１の出力モードが選択され、電磁コイル３１への通電されず、制御弁６が開いたままの状態でステップ４０に戻る。つまり、第１室外熱交換器５入口に着霜が成長しないような条件では、制御弁６は開いたままとなる。
【００１９】
次に室外気温が低くなると、蒸発器として作用する第１室外熱交換器５、第２室外熱交換器７の冷媒温度は室外気温より低くなり、大気から吸熱する。ここで非共沸混合冷媒を用いると、その非等温性のために冷媒の乾き度が大きくなるに従い冷媒温度は上昇する。そのため、第１室外熱交換器５の中央から出口までや第２室外熱交換器７の温度が０℃以上な場合でも、第１室外熱交換器５の入口は０℃に低下し第１室外熱交換器５の入口のみに着霜が始まる。そして、Ｔ_e＜Ｔ₂となり、第１室外熱交換器５に着霜が成長する温度条件になるとステップ４１で「ＹＥＳ」の判定がなされ、ステップ４３に進みメモリ２９内蔵の選択手段により記憶回路の第２出力モードが選択され、出力回路３０より出力が出て電磁コイル３１へ通電されて制御弁６が閉まる。制御弁６が閉まると冷媒は第２絞り装置８に流れ第２絞り装置８前後で圧力差が生じる。この時、第２室外熱交換器７の大きさは第１室外熱交換器５より大きいため、第２室外熱交換器７の冷媒圧力は余り変化せず、第１室外熱交換器５の冷媒圧力が上昇し、第１室外熱交換器５の冷媒温度も上昇する。そして、ステップ４４で第１室外熱交換器５の冷媒温度Ｔ_eを検出し、ステップ４５で第１室外熱交換器５の冷媒温度Ｔ_eと第１設定温度Ｔ₁（例えば１℃）との比較演算を行う。ステップ４５でＴ_e＜Ｔ _１であれば「ＮＯ」の判定によりステップ４６に進む。ステップ４６では第１室外熱交換器５の冷媒温度Ｔ_eと第３設定温度Ｔ₃（例えば−５℃）との比較演算を行い、Ｔ_e≧Ｔ _３であれば「ＮＯ」の判定によりステップ４３に戻り、記憶回路の第２出力モードが選択され続け、出力回路３０より信号が出力されて電磁コイル３１へ通電されて制御弁６が閉まったままとなり、第１室外熱交換器５の霜は解ける。そして、室外気温が上昇する等してＴ_e≧Ｔ₁となると、ステップ４２に進み、記憶回路の第１の出力モードが選択され、電磁コイル３１への通電されず、制御弁６が開き、ステップ４０に戻る。従って、第１室外熱交換器５の霜は解け成長しない。
【００２０】
さらに、外気温が下がり第１および第２室外熱交換器５、７全体に着霜が成長する状態になると、ステップ４６で第１室外熱交換器５の冷媒温度Ｔ_eと第３設定温度Ｔ₃との比較演算を行い、Ｔ_e ＜Ｔ₃となると記憶回路の第１の出力モードが選択され、電磁コイル３１への通電されず、制御弁６が開く。冷媒は第２絞り装置８を流れず減圧されないため、制御弁６前後で冷媒温度の差は生じない。このように制御弁６前後で圧力差は付かないため、第１、第２室外熱交換器５、７を有効に利用し効率の良い暖房運転を可能にできる。
【００２１】
この様に、室外熱交換器の着霜を防ぎ、効率の良い暖房運転が可能となる。
【００２２】
なお、上記説明は制御弁６とそれと並列に設けた第２絞り装置８を用いて説明したが、制御弁６に絞り機構を設け、制御弁６が動作した場合に、制御弁６内の冷媒流路が狭められ、制御弁６前後で圧力差が生じるようにすれば、より簡単な構成で室外熱交換器の着霜を防ぎ、効率の良い暖房運転が可能となる。
【００２３】
（実施例２）
図５において、１は圧縮機、２は四方弁、３は室内熱交換器、４は絞り装置、５は第１室外熱交換器、９は制御弁、７は第２室外熱交換器で、順次環状に接続されて主回路を構成し、制御弁９と並列に第２絞り装置８を設け冷凍サイクルを構成している。なお、第２室外熱交換器７の大きさは第１室外熱交換器５より大きい。ここで、第１の実施例と異な
るのは第１熱交換器の温度を検出して温度検出信号を出力する冷媒温度検出器２４と弁制御装置２２がないことと、制御弁９の構造である。
【００２４】
図６は、制御弁９の断面図である。
【００２５】
図６において、１０は弁体、１１は弁座、１２はバイアスバネ、１３は第１形状記憶合金バネ、１４は第１流路である。
【００２６】
図７は第１形状記憶合金バネ１３の温度−ひずみ曲線（ヒステリシス曲線）である。加熱時と冷却時の動作温度には温度差、すなわち温度ヒステリシスがあり、第１形状記憶合金バネ１３は加熱時の変態温度Ｔ１（例えば０℃）に、冷却時の変態温度Ｔ２（例えば−２℃）に調節している。
【００２７】
上記構成において、制御弁９の動作を説明する。
【００２８】
第１形状記憶合金バネ１３は設定した変態温度Ｔ１以上になると伸長し、バイアスバネ１２のバネ力に抗して弁体１０を押動し第１流路１４は開状態となり、冷媒は第２絞り装置８を流れず第１流路１４を流れる。一方、第１形状記憶合金バネ１３は設定変態温度Ｔ２より低くなると、バイアスバネ１２に押動され弁体１０は弁座１１に当たり、第１流路１４は閉状態となる。そのため、冷媒は第２絞り装置８しか流れることができず減圧され、冷媒の温度は低下する。
【００２９】
次に冷凍装置運転時の制御弁９の動作を説明する。
【００３０】
暖房運転時、室外気温が高く、制御弁９を流れる冷媒の温度が設定変態温度Ｔ２より高い時は、第１形状記憶合金バネ１３はバイアスバネ１２のバネ力に抗して弁体１０を押動しバイアスバネ１２を圧縮するため、第１流路１４は開状態となる。冷媒は第２絞り装置８に流れないため減圧されず、制御弁９前後で冷媒温度の差は生じない。
【００３１】
しかし室外気温が低くなると、蒸発器として作用する第１室外熱交換器５、第２室外熱交換器７の温度は室外気温より低くなり、大気から吸熱するが、非共沸混合冷媒を用いると、その非等温性のために冷媒の乾き度が大きくなるに従い冷媒温度は上昇する。そのため、第１室外熱交換器５の中央から出口までや第２室外熱交換器７の温度が０℃以上な場合でも、第１室外熱交換器５の入口は０℃以下に低下し第１室外熱交換器５の入口のみに着霜が始まる。そして、制御弁９を流れる冷媒の温度が第１形状記憶合金バネ１３の設定変態温度Ｔ２より低くなると、図８のように第１形状記憶合金バネ１３はバイアスバネ１２に押動され弁体１０を弁座１１に押し当て、第１流路１４は閉状態となる。冷媒は第２絞り装置８しか流れることができず第２絞り装置８前後で圧力差が生じる。この時、第２室外熱交換器７の大きさは第１室外熱交換器５より大きいため、第２室外熱交換器７の冷媒圧力は余り変化せず、第１室外熱交換器５の冷媒圧力が上昇し、第１室外熱交換器５の入口冷媒温度も上昇する。従って、第１室外熱交換器５の入口の霜は解け成長しない。
【００３２】
また、制御弁９が動作している状態で、室外気温が上昇する等して第１室外熱交換器５に着霜が起こらないような状態で、制御弁９の冷媒温度が第１形状記憶合金バネ１３の設定変態温度Ｔ１より高くなると、図６のように第１形状記憶合金バネ１３は変態し伸びバイアスバネ１２を圧縮し弁体１０を弁座１１から離して、第１流路１４は開状態となる。冷媒は第２絞り装置８を流れず減圧されないため、制御弁９前後で冷媒温度の差は生じない。
【００３３】
このように、室外熱交換器の着霜を防ぎ、効率の良い暖房運転が可能となる。
【００３４】
（実施例３）
図９において、１は圧縮機、２は四方弁、３は室内熱交換器、４は絞り装置、５は第１室外熱交換器、１８は制御弁、７は第２室外熱交換器で、順次環状に接続されて主回路を構成し、制御弁１８と並列に第２絞り装置８を設け冷凍サイクルを構成している。なお、第２室外熱交換器７の大きさは第１室外熱交換器５より大きい。ここで、第２の実施例と異なるのは制御弁１８の構造である。
【００３５】
図１０は、制御弁１８の断面図である。
【００３６】
図１０において、１０は弁体、１１は摺動可能な弁座、１２は第１バイアスバネ、１３は第１形状記憶合金バネ、１４は第１流路、１５は第２バイアスバネ、１６は第２形状記憶合金バネ、１７は弁体１０の移動を止めるストッパである。
【００３７】
図１１は第１形状記憶合金バネで１３と第２形状記憶合金バネ１６の温度−ひずみ曲線（ヒステリシス曲線）である。加熱時と冷却時の動作温度には温度差、すなわち温度ヒステリシスがあり、第１形状記憶合金バネ１３は加熱時の変態温度Ｔ１（例えば０℃）に、冷却時の変態温度Ｔ２（例えば−２℃）に調節し、第２形状記憶合金バネ１６は加熱時の変態温度Ｔ３（例えば−３℃）に、冷却時の変態温度Ｔ４（例えば−５℃）に調節している。
【００３８】
上記構成において、制御弁１８の動作を説明する。
【００３９】
第１形状記憶合金バネ１３は設定した変態温度Ｔ１以上になると伸長し、第１バイアスバネ１２のバネ力に抗して弁体１０を押動し第１流路１４は開状態となる。一方、第１形状記憶合金バネ１３は設定変態温度Ｔ２より低くなると、第１バイアスバネ１２に押動された弁体１０は弁座１１に当たり、第１流路１４は閉状態となる。そのため、冷媒は第２絞り装置８しか流れることができず、第２絞り装置８前後で減圧され、冷媒の温度は低下する。また、第２形状記憶合金バネ１６は設定変態温度Ｔ４より低くなると、第２バイアスバネ１５のバネ力に抗することができず収縮する。弁座１１は第２バイアスバネ１５により押動されるが、弁体１０はストッパ１７により止められてしまうため、弁座１１の移動距離を弁体１０の移動距離よりも長くなるように第１バイアスバネ１２、第１形状記憶合金バネ１３、第２バイアスバネ１５、第２形状記憶合金バネ１６の力を調整すれば、第１流路１４は開状態となる。
【００４０】
次に冷凍装置運転時の制御弁１８の動作を説明する。
【００４１】
暖房運転時、室外気温が高く、制御弁１８を流れる冷媒の温度が設定変態温度Ｔ２より高い時は、図１０のように第１形状記憶合金バネ１３は第１バイアスバネ１２のバネ力に抗して弁体１０を押動し第１バイアスバネ１２を圧縮し、第２形状記憶合金バネ１６は第２バイアスバネ１５のバネ力に抗して弁座１１を押動し第２バイアスバネ１５を圧縮するため、第１流路１４は開状態となる。冷媒は第２絞り装置８を流れないため減圧されず、制御弁１８前後で冷媒温度の差は生じない。
【００４２】
しかし室外気温が低くなると、蒸発器として作用する第１室外熱交換器５、第２室外熱交換器７の温度は室外気温より低くなり、大気から吸熱するが、非共沸混合冷媒を用いると、その非等温性のために冷媒の乾き度が大きくなるに従い冷媒温度は上昇する。そのため、第１室外熱交換器５の中央から出口までや第２室外熱交換器７の温度が０℃以上な場合でも、第１室外熱交換器５の入口は０℃以下に低下し第１室外熱交換器５の入口のみに着霜が始まる。そして、制御弁１８を流れる冷媒の温度が第１形状記憶合金バネ１３の設
定変態温度Ｔ２より低く第２形状記憶合金バネ１６の設定変態温度Ｔ４より高いと、図１２のように第１形状記憶合金バネ１３は第１バイアスバネ１２に押動され弁体１０を弁座１１に押し当て、第２形状記憶合金バネ１６は第２バイアスバネ１５のバネ力に抗して弁座１１を押し第２バイアスバネ１５を圧縮するため、第１流路１４は閉状態となる。その結果、冷媒は第２絞り装置８しか流れることができず第２絞り装置８前後で圧力差が生じる。この時、第２室外熱交換器７の大きさは第１室外熱交換器５より大きいため、第２室外熱交換器７の冷媒圧力は余り変化せず、第１室外熱交換器５の冷媒圧力が上昇し、第１室外熱交換器５の入口冷媒温度も上昇する。従って、第１室外熱交換器５の入口の霜は解け成長しない。
【００４３】
さらに、制御弁１８の冷媒の温度が第２形状記憶合金バネ１６の設定変態温度Ｔ４より低くなると、第１および第２室外熱交換器５、７全体に着霜が成長する状態であるため、図１３のように第２形状記憶合金バネ１６は第２バイアスバネ１５のバネ力に抗すことができず収縮し、弁座１１は第２バイアスバネ１５に押動されるが、弁体１０はストッパ１７により止められてしまうため、第１流路１４は開状態となる。冷媒は第２絞り装置８を流れず減圧されないため、制御弁１８前後で冷媒温度の差は生じない。このように制御弁１８前後で圧力差は付かないため、第１、第２室外熱交換器５、７を有効に利用し効率の良い暖房運転を可能にできる。
【００４４】
また、制御弁１８の温度が低く、図１３のように第１、第２バイアスバネ１２、１５に押動され、第１、第２形状記憶合金バネ１３、１６が変態し収縮し、制御弁１８が開いている状態から、室外気温が上昇する等で制御弁１８を流れている冷媒の温度が上昇し、第２形状記憶合金バネ１６の設定変態温度Ｔ３より高くなり、第１および第２室外熱交換器５、７全体に着霜せず、第１室外熱交換器５の入口のみに着霜するような状態になると、図１２のように第２形状記憶合金バネ１６は変態し伸び第２バイアスバネ１５を圧縮し弁座１１を弁体１０に押し当てるため、第１流路１４は閉状態となる。その結果、冷媒は第２絞り装置８しか流れることができず第２絞り装置８前後で圧力差が生じ、第１室外熱交換器５の冷媒圧力が上昇し、第１室外熱交換器５の入口冷媒温度も上昇する。従って、第１室外熱交換器５の入口の霜は解け成長しない。
【００４５】
さらに、室外気温が上昇し、第１室外熱交換器５に着霜が起こらないような状態で、制御弁１８を流れる冷媒の温度が第１形状記憶合金バネ１３の設定変態温度Ｔ１より高くなると、図１０のように第１形状記憶合金バネ１３は変態し伸び第１バイアスバネ１２を圧縮し弁体１０を弁座１１から離して、第１流路１４は開状態となる。冷媒は第２絞り装置８を流れず減圧されないため、制御弁１８前後で冷媒温度の差は生じない。
【００４６】
このように、室外熱交換器の部分的な着霜を防ぎ、また、室外熱交換器全体に着霜するような状態では制御弁を開き効率の良い暖房運転が可能となる。
【００４７】
（実施例４）
図１４は、本発明の冷凍装置の第４の実施例における冷凍サイクル図である。
【００４８】
図１４において、１は圧縮機、２は四方弁、３は室内熱交換器、４は絞り装置、５は第１室外熱交換器、１９は制御弁、７は第２室外熱交換器で、順次環状に接続されて冷凍サイクルを構成し、第２室外熱交換器の大きさは第１室外熱交換器より大きい。ここで、第２の実施例と異なるのは制御弁１９の構造で、減圧機構を持つことである。
【００４９】
図１５は、制御弁１９の断面図である。
【００５０】
図１５において、９は弁本体、１０は弁体、１１は弁座、１２はバイアスバネ、１３は
第１形状記憶合金バネ、１４は第１流路、２０は第２流路である。
【００５１】
第１形状記憶合金バネ１３の温度−ひずみ曲線（ヒステリシス曲線）は、図７の第２の実施例のものと同一である。
【００５２】
上記構成において、制御弁１９の動作を説明する。
【００５３】
第１形状記憶合金バネ１３は設定した変態温度Ｔ１以上になると伸長し、バイアスバネ１２のバネ力に抗して弁体１０を押動し第１流路１４は開状態となり、冷媒は第１流路１４を流れる。一方、第１形状記憶合金バネ１３は設定変態温度Ｔ２より低くなると、バイアスバネ１２に押動され弁体１０は弁座１１に当たり、第１流路１４は閉状態となる。そのため、冷媒は第２流路２０しか流れることができず流路が狭められるため、減圧され、冷媒の温度は低下する。
【００５４】
次に冷凍装置運転時の制御弁１９の動作を説明する。
【００５５】
暖房運転時、室外気温が高く、制御弁１９を流れる冷媒の温度が設定変態温度Ｔ２より高い時は、図１５のように第１形状記憶合金バネ１３はバイアスバネ１２のバネ力に抗して弁体１０を押動しバイアスバネ１２を圧縮するため、第１流路１４は開状態となる。冷媒は制御弁１９により減圧されず、制御弁１９前後で冷媒温度の差は生じない。
【００５６】
しかし室外気温が低くなると、蒸発器として作用する第１室外熱交換器５、第２室外熱交換器７の温度は室外気温より低くなり、大気から吸熱するが、非共沸混合冷媒を用いると、その非等温性のために冷媒の乾き度が大きくなるに従い冷媒温度は上昇する。そのため、第１室外熱交換器５の中央から出口までや第２室外熱交換器７の温度が０℃以上な場合でも、第１室外熱交換器５の入口は０℃以下に低下し第１室外熱交換器５の入口のみに着霜が始まる。そして、制御弁１９を流れる冷媒の温度が第１形状記憶合金バネ１３の設定変態温度Ｔ２より低くなると、図１６のように第１形状記憶合金バネ１３はバイアスバネ１２に押動され弁体１０を弁座１１に押し当て、第１流路１４は閉状態となる。冷媒は第２流路２０しか流れることができず流路が狭められるため、制御弁１９前後で圧力差が生じる。この時、第２室外熱交換器７の大きさは第１室外熱交換器５より大きいため、第２室外熱交換器７の冷媒圧力は余り変化せず、第１室外熱交換器５の冷媒圧力が上昇し、第１室外熱交換器５の入口冷媒温度も上昇する。従って第１室外熱交換器５の入口の霜は解け成長しない。
【００５７】
また、制御弁１９が動作している状態で、室外気温が上昇する等して第１室外熱交換器５に着霜が起こらないような状態で、制御弁１９の冷媒温度が第１形状記憶合金バネ１３の設定変態温度Ｔ１より高くなると、図１５のように第１形状記憶合金バネ１３は変態し伸びバイアスバネ１２を圧縮し弁体１０を弁座１１から離して、第１流路１４は開状態となる。冷媒は減圧されないため、制御弁１９前後で冷媒温度の差は生じない。
【００５８】
このように、減圧機構を持つ制御弁を用いることで第２絞り装置は不要となり、室外熱交換器の部分的な着霜を防ぎ、効率の良い暖房運転が可能となる。
【００５９】
（実施例５）
図１７において、１は圧縮機、２は四方弁、３は室内熱交換器、４は絞り装置、５は第１室外熱交換器、２１は制御弁、７は第２室外熱交換器で、順次環状に接続されて冷凍サイクルを構成している。なお、第２室外熱交換器７の大きさは第１室外熱交換器５より大きい。ここで、第４の実施例と異なるのは制御弁２１の構造である。
【００６０】
図１８は、制御弁２１の断面図である。
【００６１】
図１８において、１０は弁体、１１は摺動可能な弁座、１２は第１バイアスバネ、１３は第１形状記憶合金バネ、１４は第１流路、１５は第２バイアスバネ、１６は第２形状記憶合金バネ、１７は弁体１０の移動を止めるストッパ、２０は第２流路である。
【００６２】
第１形状記憶合金バネ１３と第２形状記憶合金バネ１６の温度−ひずみ曲線（ヒステリシス曲線）は第３の実施例の図１１と同一である。
【００６３】
上記構成において、制御弁２１の動作を説明する。
【００６４】
第１形状記憶合金バネ１３は設定した変態温度Ｔ１以上になると伸長し、第１バイアスバネ１２のバネ力に抗して弁体１０を押動し第１流路１４は開状態となる。一方、第１形状記憶合金バネ１３は設定変態温度Ｔ２より低くなると、第１バイアスバネ１２に押動された弁体１０は弁座１１に当たり、第１流路１４は閉状態となる。そのため、冷媒は第２流路２０しか流れることができず流路が狭められるため、減圧され、冷媒の温度は低下する。
【００６５】
また、第２形状記憶合金バネ１６は設定変態温度Ｔ４より低くなると、第２バイアスバネ１５のバネ力に抗すことができず収縮する。弁座１１は第２バイアスバネ１５により押動されるが、弁体１０はストッパ１７により止められてしまうため、弁座１１の移動距離を弁体１０の移動距離よりも長くなるように第１バイアスバネ１２、第１形状記憶合金バネ１３、第２バイアスバネ１５、第２形状記憶合金バネ１６の力を調整すれば、第１流路１４は開状態となる。
【００６６】
次に冷凍装置運転時の制御弁２１の動作を説明する。
【００６７】
暖房運転時、室外気温が高く、制御弁２１を流れる冷媒の温度が設定変態温度Ｔ２より高い時は、図１８のように第１形状記憶合金バネ１３は第１バイアスバネ１２のバネ力に抗して弁体１０を押動し第１バイアスバネ１２を圧縮し、第２形状記憶合金バネ１６は第２バイアスバネ１５のバネ力に抗して弁座１１を押動し第２バイアスバネ１５を圧縮するため、第１流路１４は開状態となり、冷媒は減圧されず、制御弁２１前後で冷媒温度の差は生じない。
【００６８】
しかし室外気温が低くなると、蒸発器として作用する第１室外熱交換器５、第２室外熱交換器７の温度は室外気温より低くなり、大気から吸熱するが、非共沸混合冷媒を用いると、その非等温性のために冷媒の乾き度が大きくなるに従い冷媒温度は上昇する。そのため、第１室外熱交換器５の中央から出口までや第２室外熱交換器７の温度が０℃以上な場合でも、第１室外熱交換器５の入口は０℃以下に低下し第１室外熱交換器５の入口のみに着霜が始まる。そして、制御弁２１を流れる冷媒の温度が第１形状記憶合金バネ１３の設定変態温度Ｔ２より低く第２形状記憶合金バネ１６の設定変態温度Ｔ４より高いと、図１９のように第１形状記憶合金バネ１３は第１バイアスバネ１２に押動され弁体１０を弁座１１に押し当て、第２形状記憶合金バネ１６は第２バイアスバネ１５のバネ力に抗して弁座１１を押し第２バイアスバネ１５を圧縮するため、第１流路１４は閉状態となる。その結果、冷媒は第２流路２０しか流れることができず流路が狭められるため、制御弁２１前後で圧力差が生じる。この時、第２室外熱交換器７の大きさは第１室外熱交換器５より大きいため、第２室外熱交換器７の冷媒圧力は余り変化せず、第１室外熱交換器５の冷媒圧力が上昇し、第１室外熱交換器５の入口冷媒温度も上昇する。従って、第１室外熱交換器５の入口の霜は解け成長しない。
【００６９】
さらに、制御弁２１の冷媒の温度が第２形状記憶合金バネ１６の設定変態温度Ｔ４より低くなると、第１および第２室外熱交換器５、７全体に着霜が成長する状態であるため、図２０のように第２形状記憶合金バネ１６は第２バイアスバネ１５のバネ力に抗すことができず収縮し、弁座１１は第２バイアスバネ１５に押動されるが、弁体１０はストッパ１７により止められてしまうため、第１流路１４は開状態となる。冷媒は減圧されないため、制御弁２１前後で冷媒温度の差は生じない。このように制御弁２１前後で圧力差は付かないため、第１、第２室外熱交換器５、７を有効に利用し効率の良い暖房運転を可能にできる。
【００７０】
また、制御弁２１の温度が低く図２０のように、第１、第２バイアスバネ１２、１５に押動され、第１、第２形状記憶合金バネ１３、１６が変態し収縮し、制御弁２１が開いている状態から、室外気温が上昇する等で制御弁２１を流れている冷媒の温度が上昇し、第２形状記憶合金バネ１６の設定変態温度Ｔ３より高くなり、第１および第２室外熱交換器５、７全体に着霜せず、第１室外熱交換器５の入口のみに着霜するような状態になると、図１９のように第２形状記憶合金バネ１６は変態し伸び第２バイアスバネ１５を圧縮し弁座１１を弁体１０に押し当てるため、第１流路１４は閉状態となる。その結果、冷媒は第２流路２０しか流れることができず流路が狭められるため、制御弁２１前後で圧力差が生じ、第１室外熱交換器５の冷媒圧力が上昇し、第１室外熱交換器５の入口冷媒温度も上昇する。従って、第１室外熱交換器５の入口の霜は解け成長しない。
【００７１】
さらに、室外気温が上昇し、第１室外熱交換器５に着霜が起こらないような状態で、制御弁２１を流れる冷媒の温度が第１形状記憶合金バネ１３の設定変態温度Ｔ１より高くなると、図１８のように第１形状記憶合金バネ１３は変態し伸び第１バイアスバネ１２を圧縮し弁体１０を弁座１１から離して、第１流路１４は開状態となる。冷媒は減圧されないため、制御弁２１前後で冷媒温度の差は生じない。
【００７２】
このように、室外熱交換器の部分的な着霜を防ぎ、また、室外熱交換器全体に着霜するような状態では制御弁２１を開き効率の良い暖房運転が可能となる。
【００７３】
【発明の効果】
上記実施例より明らかなように本発明によれば、第１室外熱交換器、第２室外熱交換器の間に制御弁と、その制御弁と並列に第２絞り装置を設けることで、第１室外熱交換器が着霜を起こすような温度条件下において、制御弁が動作すると、冷媒は第２絞り装置に流れ、第２絞り装置の前後で冷媒に差圧が生じ、第１室外熱交換器の圧力は第２室外熱交換器の圧力より高くなり第１室外熱交換器を流れる冷媒の温度は高くなるため、第１熱交換器入口の着霜を防ぐことができ、効率の良い暖房運転を可能にできる。
【００７４】
また、本発明のように、第１室外熱交換器、第２室外熱交換器の間に減圧機構を有し形状記憶合金バネを内蔵した制御弁を設けることで、室外熱交換器が着霜を起こすような条件下において形状記憶合金バネが変態しバイアスバネにより押されてたわみ、弁体を弁座に押しつけ冷媒の流路を狭めると、冷媒は制御弁の前後で冷媒に差圧が生じ、第１室外熱交換器の圧力は第２室外熱交換器の圧力より高くなり第１室外熱交換器を流れる冷媒の温度は高くなるため、第１熱交換器の着霜を防ぐことができ、効率の良い暖房運転を可能にできるとともに、別の絞り装置が不要となる。
【図面の簡単な説明】
【図１】本発明の実施例を示す冷凍装置の冷凍サイクル図
【図２】本発明の実施例を示す冷凍装置の弁制御装置の電気回路図
【図３】本発明の実施例を示す冷凍装置の弁制御装置のブロック図
【図４】本発明の実施例を示す冷凍装置の弁制御装置のフローチャート
【図５】本発明の他の実施例を示す冷凍装置の冷凍サイクル図
【図６】本発明の他の冷凍装置に用いる制御弁の断面図
【図７】本発明の他の冷凍装置に用いる制御弁の形状記憶合金バネの温度−ひずみ曲線図
【図８】本発明の他の冷凍装置に用いる制御弁の動作を示す断面図
【図９】本発明の他の実施例を示す冷凍装置の冷凍サイクル図
【図１０】本発明の他の実施例を示す冷凍装置に用いる制御弁の断面図
【図１１】本発明の他の実施例を示す冷凍装置に用いる制御弁の形状記憶合金バネの温度−ひずみ曲線図
【図１２】本発明の他の実施例を示す冷凍装置に用いる制御弁の動作を示す断面図
【図１３】本発明の他の実施例を示す冷凍装置に用いる制御弁の動作を示す断面図
【図１４】本発明のさらに他の実施例を示す冷凍装置の冷凍サイクル図
【図１５】本発明のさらに他の実施例を示す冷凍装置に用いる制御弁の断面図
【図１６】本発明のさらに他の実施例を示す冷凍装置に用いる制御弁の動作を示す断面図
【図１７】本発明のさらに他の実施の形態を示す冷凍装置の冷凍サイクル図
【図１８】本発明のさらに他の実施の形態を示す冷凍装置に用いる制御弁の断面図
【図１９】本発明のさらに他の実施の形態を示す冷凍装置に用いる制御弁の動作を示す断面図
【図２０】本発明のさらに他の実施の形態を示す冷凍装置に用いる制御弁の動作を示す断面図
【図２１】従来の冷凍装置の冷凍サイクル図
【符号の説明】
１圧縮機
２四方弁
３室内熱交換器
４絞り装置
５第１室外熱交換器
６制御弁
７第２室外熱交換器
８第２絞り装置
９制御弁
１０弁体
１１弁座
１２バイアスバネ
１３第１形状記憶合金バネ
１４第１流路
１５第２バイアスバネ
１６第２形状記憶合金バネ
１７ストッパ
１８制御弁
１９制御弁
２０第２流路
２１制御弁
２２弁制御装置
２３電源スイッチ
２４冷媒温度検出器
２５Ａ／Ｄ変換装置
２６マイクロコンピュータ（ＬＳＩ）
２７入力回路
２８ＣＰＵ
２９メモリ
３０出力回路
３１電磁コイル[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a refrigeration apparatus using a non-azeotropic refrigerant mixture.
[0002]
[Prior art]
  In recent years, mixed refrigerants have attracted attention as alternative refrigerants for refrigeration equipment in accordance with regulations on CFCs and HCFCs. An example of a conventional refrigeration apparatus using a non-azeotropic refrigerant mixture will be described below with reference to the drawings.
[0003]
  FIG. 21 shows a refrigeration cycle of a refrigeration apparatus using a conventional non-azeotropic refrigerant mixture.
[0004]
  In FIG. 21, 50 is a compressor, 51 is a four-way valve, 52 is an indoor heat exchanger, 53 is an expansion device, and 54 is an outdoor heat exchanger, which are sequentially connected in an annular form to constitute a main circuit.
[0005]
  The operation of the refrigeration apparatus configured as described above will be described below.
[0006]
  The high-temperature and high-pressure refrigerant vapor compressed by the compressor 50 dissipates heat in the indoor heat exchanger 52 through the four-way valve 51 and is condensed and liquefied. Thereafter, it is expanded under reduced pressure by the expansion device 53 to become a low-temperature and low-pressure refrigerant. Then, after absorbing heat by the outdoor heat exchanger 54 and evaporating and vaporizing it, it becomes low-temperature and low-pressure refrigerant vapor, and is compressed again by the compressor 50 to repeat the refrigeration cycle (for example, JP-A-3-13766).
[0007]
[Problems to be solved by the invention]
  The outdoor heat exchanger during heating operation acts as an evaporator, and the refrigerant changes in a gas-liquid two-phase state. In the case of a single refrigerant, the inlet refrigerant temperature and outlet refrigerant temperature of the heat exchanger are the same, but the non-azeotropic refrigerant mixture is non-isothermal, and the temperature increases as the degree of dryness of the refrigerant increases. The exchanger inlet refrigerant temperature is lower than the outdoor heat exchanger outlet refrigerant temperature. Therefore, in the configuration as described above, at the time of heating operation, even if the outdoor temperature does not frost on the outdoor heat exchanger in the case of a single refrigerant, frost is formed at the inlet of the outdoor heat exchanger if a non-azeotropic refrigerant mixture is used. It is conceivable that the heating capacity decreases.
[0008]
  The present invention solves the above-described problems of the conventional example, and aims to prevent partial frost formation of an outdoor heat exchanger and enable efficient heating operation.
[0009]
[Means for Solving the Problems]
  In order to solve the above problems, the present inventionUsing a non-azeotropic refrigerant mixture, the compressor, the four-way valve, the indoor heat exchanger, the expansion device, the first outdoor heat exchanger, the control valve, and the second outdoor heat exchanger are connected in an annular shape, and the first outdoor heat exchange The second outdoor heat exchanger is made larger than the condenser, and includes a second expansion device provided in parallel with the control valve. The set temperature for opening and closing the control valve is the first set temperature, The value is set smaller as the second set temperature and the third set temperature are reached. When the refrigerant temperature of the first outdoor heat exchanger is lower than the third set temperature, the control valve is opened, and the third set temperature is set. The refrigeration apparatus is configured to close the control valve when the temperature is lower than the second set temperature and open the control valve when the temperature is equal to or higher than the first set temperature.is there. Provided in parallel with the control valveBy the second diaphragmWhen the control valve operates under a temperature condition that causes the first outdoor heat exchanger to form frost, the refrigerant flows into the second expansion device, and a differential pressure is generated in the refrigerant before and after the second expansion device. Since the pressure of the outdoor heat exchanger becomes higher than the pressure of the second outdoor heat exchanger and the temperature of the refrigerant flowing through the first outdoor heat exchanger becomes high, frosting at the inlet of the first heat exchanger can be prevented,
Efficient heating operation is possible.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
  To solve the above problemsThe present inventionControl valve, saidControl valve andA second diaphragm device is provided in parallel. As a result, when the control valve operates under a temperature condition in which the first outdoor heat exchanger causes frost formation, the refrigerant flows into the second expansion device, and a differential pressure is generated in the refrigerant before and after the second expansion device. Since the pressure of the first outdoor heat exchanger becomes higher than the pressure of the second outdoor heat exchanger and the temperature of the refrigerant flowing through the first outdoor heat exchanger becomes higher, it is possible to prevent frost formation at the inlet of the first heat exchanger. And efficient heating operation is possible.
[0011]
  Also,The present inventionIs provided with a control valve having a pressure reducing mechanism between the first outdoor heat exchanger and the second outdoor heat exchanger and having a shape memory alloy spring built therein, so that the outdoor heat exchanger is frosted. When the shape memory alloy spring is transformed and bent by the bias spring and the valve body is pressed against the valve seat to narrow the flow path of the refrigerant, the refrigerant has a differential pressure before and after the control valve, and the first outdoor heat exchanger Since the pressure is higher than the pressure of the second outdoor heat exchanger and the temperature of the refrigerant flowing through the first outdoor heat exchanger is increased, frosting at the inlet of the first heat exchanger can be prevented, and another throttle device, valve A control device is unnecessary, and efficient heating operation can be realized with a simpler configuration.
[0012]
【Example】
  Embodiments of the present invention will be described below with reference to the drawings.
[0013]
  (Example 1)
  FIG. 1 is a refrigeration cycle diagram in the first embodiment of the refrigeration apparatus of the present invention.
[0014]
  In FIG. 1, 1 is a compressor, 2 is a four-way valve, 3 is an indoor heat exchanger, 4 is a throttle device, 5 is a first outdoor heat exchanger, 6 is a control valve, and 7 is a second outdoor heat exchanger. A main circuit is formed by sequentially connecting in an annular manner, and a refrigeration cycle is configured by providing a second expansion device 8 in parallel with the control valve 6. The size of the second outdoor heat exchanger 7 is larger than that of the first outdoor heat exchanger 5. large. 22 is a valve control device that controls the opening and closing of the control valve 6, and 24 is a refrigerant temperature detector that detects the refrigerant temperature of the first outdoor heat exchanger 5 and outputs a temperature detection signal.
[0015]
  FIG. 2 is an electric circuit diagram showing an electrical connection of the refrigeration apparatus shown in FIG. In the figure, 24 is a refrigerant temperature detector for detecting the refrigerant temperature of the first outdoor heat exchanger 5, 25 is an A / D converter, 26 is a microcomputer (hereinafter referred to as LSI), and an input circuit 27, A CPU 28, a memory 29, and an output circuit 30 are provided. The output of the refrigerant temperature detector 24 of the first outdoor heat exchanger 5 is input to the input circuit 27 via the A / D conversion device 25. 31 is an electromagnetic coil that operates to open and close the control valve 6 according to the output of the output circuit 30.
[0016]
  Here, the block diagram shown in FIG. 3 and the electric circuit diagram shown in FIG. 2 will be described. The refrigerant temperature detector 24 of the first outdoor heat exchanger 5 in FIG. 2 is the refrigerant of the first outdoor heat exchanger 5 in FIG. The refrigerant temperature detecting means for detecting and outputting the temperature, the LSI 26 in FIG. 2, compares the value detected by the refrigerant temperature detecting means in FIG. 3 with the set value and outputs a control signal, and the control valve 6 This corresponds to a storage unit that stores an output mode for controlling opening and closing, and a selection unit that selects one of the output modes of the storage unit based on an output signal generated from the comparison unit. And the electromagnetic coil 31 which opens and closes the control valve 6 of FIG. 2 is equivalent to the output means of FIG.
[0017]
  In the above configuration, the configuration and operation of the control circuit during operation of the refrigeration apparatus will be described with reference to FIG. FIG. 4 is a flowchart showing a program of the refrigeration apparatus stored in the memory 29 of the LSI 26.
[0018]
  When the operation instruction is issued, the operation of the refrigeration apparatus starts, and at the same time, the step 40 shown in FIG. 4 is executed, and the refrigerant temperature T of the first outdoor heat exchanger 5 is_eIs detected, and in step 41, the refrigerant temperature T of the first outdoor heat exchanger 5 is detected._eWhenSecondSet temperature T₂(For example, −2 ° C.)_e≧ T₂If “NO”, the process proceeds to step 42 and the first output mode of the memory circuit is selected by the selection means built in the memory 29, the electromagnetic coil 31 is not energized, and the control valve 6 remains open. Return to step 40. That is, the control valve 6 remains open under the condition that frost does not grow at the inlet of the first outdoor heat exchanger 5.
[0019]
  Next, when the outdoor temperature is lowered, the refrigerant temperatures of the first outdoor heat exchanger 5 and the second outdoor heat exchanger 7 acting as an evaporator become lower than the outdoor temperature and absorb heat from the atmosphere. Here, when a non-azeotropic refrigerant mixture is used, the refrigerant temperature rises as the dryness of the refrigerant increases due to its non-isothermal property. Therefore, even when the temperature from the center of the first outdoor heat exchanger 5 to the outlet or the temperature of the second outdoor heat exchanger 7 is 0 ° C. or higher, the inlet of the first outdoor heat exchanger 5 is lowered to 0 ° C. Frosting begins only at the inlet of the heat exchanger 5. And T_e<T₂When the temperature condition is reached in which frost grows in the first outdoor heat exchanger 5, “YES” is determined in step 41, the process proceeds to step 43, and the second output mode of the storage circuit is selected by the selection means built in the memory 29. Then, an output is output from the output circuit 30 and the electromagnetic coil 31 is energized to close the control valve 6. When the control valve 6 is closed, the refrigerant flows into the second expansion device 8 and a pressure difference occurs between the front and rear of the second expansion device 8. At this time, since the size of the second outdoor heat exchanger 7 is larger than that of the first outdoor heat exchanger 5, the refrigerant pressure in the second outdoor heat exchanger 7 does not change so much, and the refrigerant in the first outdoor heat exchanger 5 does not change. The pressure rises and the refrigerant temperature of the first outdoor heat exchanger 5 also rises. In step 44, the refrigerant temperature T of the first outdoor heat exchanger 5 is obtained._eIn step 45, the refrigerant temperature T of the first outdoor heat exchanger 5 is detected._eAnd the first set temperature T₁Comparison operation with (for example, 1 ° C.) is performed. T in step 45_e<T ₁If so, the process proceeds to step 46 by determining “NO”. In step 46, the refrigerant temperature T of the first outdoor heat exchanger 5 is determined._eAnd the third set temperature T_Three(For example, −5 ° C.)_e≧T ₃If “NO”, the process returns to step 43, the second output mode of the memory circuit is continuously selected, a signal is output from the output circuit 30 and the electromagnetic coil 31 is energized, and the control valve 6 remains closed. The frost in the first outdoor heat exchanger 5 is thawed. And the T_e≧ T₁Then, the process proceeds to step 42 where the first output mode of the memory circuit is selected, the electromagnetic coil 31 is not energized, the control valve 6 is opened, and the process returns to step 40. Therefore, the frost of the first outdoor heat exchanger 5 does not melt and grow.
[0020]
  Further, when the outside air temperature decreases and frost forms on the entire first and second outdoor heat exchangers 5 and 7, the refrigerant temperature T of the first outdoor heat exchanger 5 is determined in step 46._eAnd the third set temperature T_ThreeAnd comparison operation with T_e <T_ThreeThen, the first output mode of the memory circuit is selected, the electromagnetic coil 31 is not energized, and the control valve 6 is opened. Since the refrigerant does not flow through the second expansion device 8 and is not depressurized, there is no refrigerant temperature difference before and after the control valve 6. Since there is no pressure difference before and after the control valve 6 in this way, the first and second outdoor heat exchangers 5 and 7 can be used effectively to enable efficient heating operation.
[0021]
  In this way, frosting of the outdoor heat exchanger is prevented and efficient heating operation is possible.
[0022]
  Although the above description has been made using the control valve 6 and the second throttle device 8 provided in parallel therewith, when the control valve 6 is provided with a throttle mechanism and the control valve 6 operates, the refrigerant in the control valve 6 If the flow path is narrowed and a pressure difference is generated before and after the control valve 6, frosting of the outdoor heat exchanger can be prevented with a simpler structure, and an efficient heating operation can be performed.
[0023]
  (Example 2)
  In FIG. 5, 1 is a compressor, 2 is a four-way valve, 3 is an indoor heat exchanger, 4 is a throttle device, 5 is a first outdoor heat exchanger, 9 is a control valve, and 7 is a second outdoor heat exchanger. The main circuit is configured by being sequentially connected in an annular shape, and a second expansion device 8 is provided in parallel with the control valve 9 to configure a refrigeration cycle. The size of the second outdoor heat exchanger 7 is larger than that of the first outdoor heat exchanger 5. Here, different from the first embodiment
This is because there is no refrigerant temperature detector 24 and a valve control device 22 for detecting the temperature of the first heat exchanger and outputting a temperature detection signal, and the structure of the control valve 9.
[0024]
  FIG. 6 is a cross-sectional view of the control valve 9.
[0025]
  In FIG. 6, 10 is a valve body, 11 is a valve seat, 12 is a bias spring, 13 is a first shape memory alloy spring, and 14 is a first flow path.
[0026]
  FIG. 7 is a temperature-strain curve (hysteresis curve) of the first shape memory alloy spring 13. There is a temperature difference, ie, temperature hysteresis, between the operating temperature during heating and cooling, and the first shape memory alloy spring 13 has a transformation temperature T2 during cooling (for example, -2) to a transformation temperature T1 during heating (for example, 0 ° C.). ℃).
[0027]
  In the above configuration, the operation of the control valve 9 will be described.
[0028]
  The first shape memory alloy spring 13 expands when it reaches the set transformation temperature T1 or higher, pushes the valve body 10 against the spring force of the bias spring 12, opens the first flow path 14, and the refrigerant is in the second state. It flows through the first flow path 14 without flowing through the expansion device 8. On the other hand, when the first shape memory alloy spring 13 becomes lower than the set transformation temperature T2, the bias spring 12 pushes the valve body 10 against the valve seat 11, and the first flow path 14 is closed. Therefore, the refrigerant can only flow through the second expansion device 8 and is depressurized, and the temperature of the refrigerant decreases.
[0029]
  Next, the operation of the control valve 9 during operation of the refrigeration apparatus will be described.
[0030]
  During the heating operation, when the outdoor air temperature is high and the temperature of the refrigerant flowing through the control valve 9 is higher than the set transformation temperature T2, the first shape memory alloy spring 13 pushes the valve body 10 against the spring force of the bias spring 12. In order to move and compress the bias spring 12, the 1st flow path 14 will be in an open state. Since the refrigerant does not flow to the second expansion device 8, it is not depressurized, and there is no difference in refrigerant temperature before and after the control valve 9.
[0031]
  However, when the outdoor air temperature decreases, the temperatures of the first outdoor heat exchanger 5 and the second outdoor heat exchanger 7 acting as an evaporator become lower than the outdoor air temperature and absorb heat from the atmosphere. However, when a non-azeotropic refrigerant mixture is used, Because of its non-isothermal property, the refrigerant temperature rises as the dryness of the refrigerant increases. Therefore, even when the temperature from the center of the first outdoor heat exchanger 5 to the outlet or the temperature of the second outdoor heat exchanger 7 is 0 ° C. or higher, the inlet of the first outdoor heat exchanger 5 is reduced to 0 ° C. or lower and the first Frosting begins only at the entrance of the outdoor heat exchanger 5. When the temperature of the refrigerant flowing through the control valve 9 becomes lower than the set transformation temperature T2 of the first shape memory alloy spring 13, the first shape memory alloy spring 13 is pushed by the bias spring 12 as shown in FIG. Is pressed against the valve seat 11, and the first flow path 14 is closed. The refrigerant can only flow through the second expansion device 8, and a pressure difference occurs between the front and rear of the second expansion device 8. At this time, since the size of the second outdoor heat exchanger 7 is larger than that of the first outdoor heat exchanger 5, the refrigerant pressure in the second outdoor heat exchanger 7 does not change so much, and the refrigerant in the first outdoor heat exchanger 5 does not change. The pressure rises and the inlet refrigerant temperature of the first outdoor heat exchanger 5 also rises. Therefore, the frost at the inlet of the first outdoor heat exchanger 5 does not melt and grow.
[0032]
  Further, the refrigerant temperature of the control valve 9 is stored in the first shape memory in such a state that frosting does not occur in the first outdoor heat exchanger 5 due to, for example, the outdoor temperature rising while the control valve 9 is operating. When the temperature becomes higher than the set transformation temperature T1 of the alloy spring 13, the first shape memory alloy spring 13 is transformed to compress the extension bias spring 12 and release the valve body 10 from the valve seat 11 as shown in FIG. Is open. Since the refrigerant does not flow through the second expansion device 8 and is not depressurized, there is no refrigerant temperature difference before and after the control valve 9.
[0033]
  Thus, frost formation of the outdoor heat exchanger is prevented, and efficient heating operation is possible.
[0034]
  (Example 3)
  9, 1 is a compressor, 2 is a four-way valve, 3 is an indoor heat exchanger, 4 is a throttle device, 5 is a first outdoor heat exchanger, 18 is a control valve, and 7 is a second outdoor heat exchanger. The main circuit is configured by sequentially connecting in an annular manner, and the second expansion device 8 is provided in parallel with the control valve 18 to configure the refrigeration cycle. The size of the second outdoor heat exchanger 7 is larger than that of the first outdoor heat exchanger 5. Here, the structure of the control valve 18 is different from the second embodiment.
[0035]
  FIG. 10 is a cross-sectional view of the control valve 18.
[0036]
  FIG.10 is a valve body, 11 is a slidable valve seat, 12 is a first bias spring, 13 is a first shape memory alloy spring, 14 is a first flow path, 15 is a second bias spring, and 16 is a second bias spring. A shape memory alloy spring 17 is a stopper that stops the movement of the valve body 10.
[0037]
  FIG. 11 is a temperature-strain curve (hysteresis curve) of the first shape memory alloy spring 13 and the second shape memory alloy spring 16. There is a temperature difference, ie, temperature hysteresis, between the operating temperature during heating and cooling, and the first shape memory alloy spring 13 has a transformation temperature T2 during cooling (for example, -2) to a transformation temperature T1 during heating (for example, 0 ° C.). The second shape memory alloy spring 16 is adjusted to a transformation temperature T3 (for example, −3 ° C.) during heating and a transformation temperature T4 (for example −5 ° C.) during cooling.
[0038]
  In the above configuration, the operation of the control valve 18 will be described.
[0039]
  The first shape memory alloy spring 13 expands when it reaches the set transformation temperature T1 or higher, pushes the valve body 10 against the spring force of the first bias spring 12, and the first flow path 14 is opened. On the other hand, when the first shape memory alloy spring 13 becomes lower than the set transformation temperature T2, the valve body 10 pushed by the first bias spring 12 hits the valve seat 11, and the first flow path 14 is closed. Therefore, the refrigerant can only flow through the second expansion device 8 and is decompressed before and after the second expansion device 8, and the temperature of the refrigerant decreases. Further, when the second shape memory alloy spring 16 becomes lower than the set transformation temperature T4, the second shape memory alloy spring 16 cannot resist the spring force of the second bias spring 15 and contracts. Although the valve seat 11 is pushed by the second bias spring 15, the valve body 10 is stopped by the stopper 17, so that the first travel distance of the valve seat 11 is longer than the travel distance of the valve body 10. If the force of the bias spring 12, the first shape memory alloy spring 13, the second bias spring 15, and the second shape memory alloy spring 16 is adjusted, the first flow path 14 is opened.
[0040]
  Next, the operation of the control valve 18 during operation of the refrigeration apparatus will be described.
[0041]
  During the heating operation, when the outdoor air temperature is high and the temperature of the refrigerant flowing through the control valve 18 is higher than the set transformation temperature T2, the first shape memory alloy spring 13 resists the spring force of the first bias spring 12 as shown in FIG. Then, the valve body 10 is pushed and the first bias spring 12 is compressed, and the second shape memory alloy spring 16 pushes the valve seat 11 against the spring force of the second bias spring 15 and the second bias spring 15. Therefore, the first flow path 14 is in an open state. Since the refrigerant does not flow through the second expansion device 8, it is not depressurized, and there is no difference in refrigerant temperature before and after the control valve 18.
[0042]
  However, when the outdoor air temperature decreases, the temperatures of the first outdoor heat exchanger 5 and the second outdoor heat exchanger 7 acting as an evaporator become lower than the outdoor air temperature and absorb heat from the atmosphere. However, when a non-azeotropic refrigerant mixture is used, Because of its non-isothermal property, the refrigerant temperature rises as the dryness of the refrigerant increases. Therefore, even when the temperature from the center of the first outdoor heat exchanger 5 to the outlet or the temperature of the second outdoor heat exchanger 7 is 0 ° C. or higher, the inlet of the first outdoor heat exchanger 5 is reduced to 0 ° C. or lower and the first Frosting begins only at the entrance of the outdoor heat exchanger 5. Then, the temperature of the refrigerant flowing through the control valve 18 is set at the first shape memory alloy spring 13.
When the temperature is lower than the constant transformation temperature T2 and higher than the set transformation temperature T4 of the second shape memory alloy spring 16, the first shape memory alloy spring 13 is pushed by the first bias spring 12 as shown in FIG. 11, the second shape memory alloy spring 16 presses the valve seat 11 against the spring force of the second bias spring 15 and compresses the second bias spring 15, so that the first flow path 14 is closed. . As a result, the refrigerant can only flow through the second expansion device 8, and a pressure difference occurs between the second expansion device 8 and the second expansion device 8. At this time, since the size of the second outdoor heat exchanger 7 is larger than that of the first outdoor heat exchanger 5, the refrigerant pressure in the second outdoor heat exchanger 7 does not change so much, and the refrigerant in the first outdoor heat exchanger 5 does not change. The pressure rises and the inlet refrigerant temperature of the first outdoor heat exchanger 5 also rises. Therefore, the frost at the inlet of the first outdoor heat exchanger 5 does not melt and grow.
[0043]
  Furthermore, when the temperature of the refrigerant of the control valve 18 becomes lower than the set transformation temperature T4 of the second shape memory alloy spring 16, frost forms on the entire first and second outdoor heat exchangers 5 and 7, As shown in FIG. 13, the second shape memory alloy spring 16 cannot resist the spring force of the second bias spring 15 and contracts, and the valve seat 11 is pushed by the second bias spring 15. Is stopped by the stopper 17, the first flow path 14 is opened. Since the refrigerant does not flow through the second expansion device 8 and is not depressurized, there is no difference in refrigerant temperature before and after the control valve 18. Thus, since there is no pressure difference before and after the control valve 18, the first and second outdoor heat exchangers 5 and 7 can be effectively used to enable efficient heating operation.
[0044]
  Further, the temperature of the control valve 18 is low, and it is pushed by the first and second bias springs 12 and 15 as shown in FIG. 13, so that the first and second shape memory alloy springs 13 and 16 are transformed and contracted, and the control valve From the open state, the temperature of the refrigerant flowing through the control valve 18 rises due to, for example, an increase in the outdoor air temperature, becomes higher than the set transformation temperature T3 of the second shape memory alloy spring 16, and the first and second When the entire outdoor heat exchangers 5 and 7 are not frosted and only the inlet of the first outdoor heat exchanger 5 is frosted, the second shape memory alloy spring 16 is transformed and stretched as shown in FIG. Since the second bias spring 15 is compressed and the valve seat 11 is pressed against the valve body 10, the first flow path 14 is closed. As a result, the refrigerant can only flow through the second expansion device 8 and a pressure difference occurs between the second expansion device 8 and the refrigerant, the refrigerant pressure in the first outdoor heat exchanger 5 rises, and the first outdoor heat exchanger 5 The inlet refrigerant temperature also increases. Therefore, the frost at the inlet of the first outdoor heat exchanger 5 does not melt and grow.
[0045]
  Furthermore, when the outdoor air temperature rises and the first outdoor heat exchanger 5 is not frosted, the temperature of the refrigerant flowing through the control valve 18 becomes higher than the set transformation temperature T1 of the first shape memory alloy spring 13. As shown in FIG. 10, the first shape memory alloy spring 13 is transformed and stretched, the first bias spring 12 is compressed, the valve body 10 is separated from the valve seat 11, and the first flow path 14 is opened. Since the refrigerant does not flow through the second expansion device 8 and is not depressurized, there is no difference in refrigerant temperature before and after the control valve 18.
[0046]
  Thus, partial frost formation of the outdoor heat exchanger is prevented, and in a state where frost formation occurs on the entire outdoor heat exchanger, the control valve is opened to enable efficient heating operation.
[0047]
  (Example 4)
  FIG. 14 is a refrigeration cycle diagram in the fourth embodiment of the refrigeration apparatus of the present invention.
[0048]
  In FIG. 14, 1 is a compressor, 2 is a four-way valve, 3 is an indoor heat exchanger, 4 is a throttle device, 5 is a first outdoor heat exchanger, 19 is a control valve, and 7 is a second outdoor heat exchanger. The refrigeration cycle is configured by sequentially connecting in an annular shape, and the size of the second outdoor heat exchanger is larger than that of the first outdoor heat exchanger. Here, the second embodiment is different from the second embodiment in the structure of the control valve 19 and having a pressure reducing mechanism.
[0049]
  FIG. 15 is a cross-sectional view of the control valve 19.
[0050]
  In FIG. 15, 9 is a valve body, 10 is a valve body, 11 is a valve seat, 12 is a bias spring, 13 is
A first shape memory alloy spring, 14 is a first flow path, and 20 is a second flow path.
[0051]
  The temperature-strain curve (hysteresis curve) of the first shape memory alloy spring 13 is the same as that of the second embodiment of FIG.
[0052]
  In the above configuration, the operation of the control valve 19 will be described.
[0053]
  The first shape memory alloy spring 13 expands when it reaches the set transformation temperature T1 or higher, pushes the valve element 10 against the spring force of the bias spring 12, opens the first flow path 14, and the refrigerant is the first. It flows through the flow path 14. On the other hand, when the first shape memory alloy spring 13 becomes lower than the set transformation temperature T2, the bias spring 12 pushes the valve body 10 against the valve seat 11, and the first flow path 14 is closed. Therefore, since the refrigerant can only flow through the second flow path 20 and the flow path is narrowed, the pressure is reduced and the temperature of the refrigerant decreases.
[0054]
  Next, the operation of the control valve 19 during operation of the refrigeration apparatus will be described.
[0055]
  During the heating operation, when the outdoor air temperature is high and the temperature of the refrigerant flowing through the control valve 19 is higher than the set transformation temperature T2, the first shape memory alloy spring 13 resists the spring force of the bias spring 12 as shown in FIG. Since the valve body 10 is pushed and the bias spring 12 is compressed, the first flow path 14 is opened. The refrigerant is not depressurized by the control valve 19, and there is no refrigerant temperature difference before and after the control valve 19.
[0056]
  However, when the outdoor air temperature decreases, the temperatures of the first outdoor heat exchanger 5 and the second outdoor heat exchanger 7 acting as an evaporator become lower than the outdoor air temperature and absorb heat from the atmosphere. However, when a non-azeotropic refrigerant mixture is used, Because of its non-isothermal property, the refrigerant temperature rises as the dryness of the refrigerant increases. Therefore, even when the temperature from the center of the first outdoor heat exchanger 5 to the outlet or the temperature of the second outdoor heat exchanger 7 is 0 ° C. or higher, the inlet of the first outdoor heat exchanger 5 is reduced to 0 ° C. or lower and the first Frosting begins only at the entrance of the outdoor heat exchanger 5. When the temperature of the refrigerant flowing through the control valve 19 becomes lower than the set transformation temperature T2 of the first shape memory alloy spring 13, the first shape memory alloy spring 13 is pushed by the bias spring 12 as shown in FIG. Is pressed against the valve seat 11, and the first flow path 14 is closed. Since the refrigerant can only flow through the second flow path 20 and the flow path is narrowed, a pressure difference is generated before and after the control valve 19. At this time, since the size of the second outdoor heat exchanger 7 is larger than that of the first outdoor heat exchanger 5, the refrigerant pressure in the second outdoor heat exchanger 7 does not change so much, and the refrigerant in the first outdoor heat exchanger 5 does not change. The pressure rises and the inlet refrigerant temperature of the first outdoor heat exchanger 5 also rises. Therefore, the frost at the inlet of the first outdoor heat exchanger 5 does not melt and grow.
[0057]
  Further, the refrigerant temperature of the control valve 19 is stored in the first shape memory in such a state that frosting does not occur in the first outdoor heat exchanger 5 due to, for example, the outdoor temperature rising while the control valve 19 is operating. When the temperature becomes higher than the set transformation temperature T1 of the alloy spring 13, the first shape memory alloy spring 13 is transformed to compress the extension bias spring 12 and release the valve body 10 from the valve seat 11 as shown in FIG. Is open. Since the refrigerant is not depressurized, there is no difference in refrigerant temperature before and after the control valve 19.
[0058]
  As described above, the use of the control valve having the pressure reducing mechanism eliminates the need for the second expansion device, prevents partial frosting of the outdoor heat exchanger, and enables efficient heating operation.
[0059]
  (Example 5)
  In FIG. 17, 1 is a compressor, 2 is a four-way valve, 3 is an indoor heat exchanger, 4 is a throttle device, 5 is a first outdoor heat exchanger, 21 is a control valve, and 7 is a second outdoor heat exchanger. The refrigeration cycle is configured by sequentially connecting in an annular shape. The size of the second outdoor heat exchanger 7 is larger than that of the first outdoor heat exchanger 5. Here, the difference from the fourth embodiment is the structure of the control valve 21.
[0060]
  FIG. 18 is a cross-sectional view of the control valve 21.
[0061]
  In FIG. 18, 10 is a valve body, 11 is a slidable valve seat, 12 is a first bias spring, 13 is a first shape memory alloy spring, 14 is a first flow path, 15 is a second bias spring, and 16 is A second shape memory alloy spring, 17 is a stopper for stopping the movement of the valve body 10, and 20 is a second flow path.
[0062]
  The temperature-strain curve (hysteresis curve) of the first shape memory alloy spring 13 and the second shape memory alloy spring 16 is the same as FIG. 11 of the third embodiment.
[0063]
  In the above configuration, the operation of the control valve 21 will be described.
[0064]
  The first shape memory alloy spring 13 expands when it reaches the set transformation temperature T1 or higher, pushes the valve body 10 against the spring force of the first bias spring 12, and the first flow path 14 is opened. On the other hand, when the first shape memory alloy spring 13 becomes lower than the set transformation temperature T2, the valve body 10 pushed by the first bias spring 12 hits the valve seat 11, and the first flow path 14 is closed. Therefore, since the refrigerant can only flow through the second flow path 20 and the flow path is narrowed, the pressure is reduced and the temperature of the refrigerant decreases.
[0065]
  Further, when the second shape memory alloy spring 16 becomes lower than the set transformation temperature T4, it cannot resist the spring force of the second bias spring 15 and contracts. Although the valve seat 11 is pushed by the second bias spring 15, the valve body 10 is stopped by the stopper 17, so that the first travel distance of the valve seat 11 is longer than the travel distance of the valve body 10. If the force of the bias spring 12, the first shape memory alloy spring 13, the second bias spring 15, and the second shape memory alloy spring 16 is adjusted, the first flow path 14 is opened.
[0066]
  Next, the operation of the control valve 21 during operation of the refrigeration apparatus will be described.
[0067]
  During the heating operation, when the outdoor air temperature is high and the temperature of the refrigerant flowing through the control valve 21 is higher than the set transformation temperature T2, the first shape memory alloy spring 13 resists the spring force of the first bias spring 12 as shown in FIG. Then, the valve body 10 is pushed and the first bias spring 12 is compressed, and the second shape memory alloy spring 16 pushes the valve seat 11 against the spring force of the second bias spring 15 and the second bias spring 15. Therefore, the first flow path 14 is opened, the refrigerant is not depressurized, and there is no refrigerant temperature difference before and after the control valve 21.
[0068]
  However, when the outdoor air temperature decreases, the temperatures of the first outdoor heat exchanger 5 and the second outdoor heat exchanger 7 acting as an evaporator become lower than the outdoor air temperature and absorb heat from the atmosphere. However, when a non-azeotropic refrigerant mixture is used, Because of its non-isothermal property, the refrigerant temperature rises as the dryness of the refrigerant increases. Therefore, even when the temperature from the center of the first outdoor heat exchanger 5 to the outlet or the temperature of the second outdoor heat exchanger 7 is 0 ° C. or higher, the inlet of the first outdoor heat exchanger 5 is reduced to 0 ° C. or lower and the first Frosting begins only at the entrance of the outdoor heat exchanger 5. Then, when the temperature of the refrigerant flowing through the control valve 21 is lower than the set transformation temperature T2 of the first shape memory alloy spring 13 and higher than the set transformation temperature T4 of the second shape memory alloy spring 16, the first shape memory as shown in FIG. The alloy spring 13 is pushed by the first bias spring 12 to press the valve body 10 against the valve seat 11, and the second shape memory alloy spring 16 pushes the valve seat 11 against the spring force of the second bias spring 15. In order to compress the 2 bias spring 15, the first flow path 14 is closed. As a result, the refrigerant can only flow through the second flow path 20 and the flow path is narrowed, so that a pressure difference occurs between the front and rear of the control valve 21. At this time, since the size of the second outdoor heat exchanger 7 is larger than that of the first outdoor heat exchanger 5, the refrigerant pressure in the second outdoor heat exchanger 7 does not change so much, and the refrigerant in the first outdoor heat exchanger 5 does not change. The pressure rises and the inlet refrigerant temperature of the first outdoor heat exchanger 5 also rises. Therefore, the frost at the inlet of the first outdoor heat exchanger 5 does not melt and grow.
[0069]
  Furthermore, when the temperature of the refrigerant of the control valve 21 becomes lower than the set transformation temperature T4 of the second shape memory alloy spring 16, frost forms on the entire first and second outdoor heat exchangers 5 and 7, As shown in FIG. 20, the second shape memory alloy spring 16 cannot resist the spring force of the second bias spring 15 and contracts, and the valve seat 11 is pushed by the second bias spring 15. Is stopped by the stopper 17, the first flow path 14 is opened. Since the refrigerant is not depressurized, there is no difference in refrigerant temperature before and after the control valve 21. Thus, since there is no pressure difference before and after the control valve 21, the first and second outdoor heat exchangers 5 and 7 can be effectively used to enable efficient heating operation.
[0070]
  Further, the temperature of the control valve 21 is low, and the first and second bias springs 12 and 15 are pushed by the first and second shape memory alloy springs 13 and 16 as shown in FIG. From the open state, the temperature of the refrigerant flowing through the control valve 21 rises due to, for example, the outdoor air temperature rising, and becomes higher than the set transformation temperature T3 of the second shape memory alloy spring 16, and the first and second When the entire outdoor heat exchangers 5 and 7 are not frosted and only the inlet of the first outdoor heat exchanger 5 is frosted, the second shape memory alloy spring 16 is transformed and stretched as shown in FIG. Since the second bias spring 15 is compressed and the valve seat 11 is pressed against the valve body 10, the first flow path 14 is closed. As a result, since the refrigerant can only flow through the second flow path 20 and the flow path is narrowed, a pressure difference occurs between the control valve 21 and the refrigerant pressure in the first outdoor heat exchanger 5 increases, and the first outdoor The inlet refrigerant temperature of the heat exchanger 5 also rises. Therefore, the frost at the inlet of the first outdoor heat exchanger 5 does not melt and grow.
[0071]
  Furthermore, when the outdoor air temperature rises and the first outdoor heat exchanger 5 is not frosted, the temperature of the refrigerant flowing through the control valve 21 becomes higher than the set transformation temperature T1 of the first shape memory alloy spring 13. As shown in FIG. 18, the first shape memory alloy spring 13 is transformed and stretched, the first bias spring 12 is compressed, the valve body 10 is separated from the valve seat 11, and the first flow path 14 is opened. Since the refrigerant is not depressurized, there is no difference in refrigerant temperature before and after the control valve 21.
[0072]
  Thus, partial frost formation of the outdoor heat exchanger is prevented, and in a state where frost is formed on the entire outdoor heat exchanger, the control valve 21 is opened to enable efficient heating operation.
[0073]
【The invention's effect】
  As is clear from the above exampleThe present inventionAccording to the present invention, there is provided a control valve between the first outdoor heat exchanger and the second outdoor heat exchanger, and the second throttle device in parallel with the control valve.SetTherefore, when the control valve operates under a temperature condition in which the first outdoor heat exchanger causes frost formation, the refrigerant flows into the second expansion device, and a differential pressure is generated in the refrigerant before and after the second expansion device. Since the pressure of the first outdoor heat exchanger becomes higher than the pressure of the second outdoor heat exchanger and the temperature of the refrigerant flowing through the first outdoor heat exchanger becomes higher, it is possible to prevent frost formation at the inlet of the first heat exchanger. And efficient heating operation is possible.
[0074]
  MaBookAs in the invention, by providing a control valve having a pressure reducing mechanism between the first outdoor heat exchanger and the second outdoor heat exchanger and incorporating a shape memory alloy spring, the outdoor heat exchanger may cause frost formation. When the shape memory alloy spring transforms and bends by being biased by the bias spring under a narrow condition, and the valve body is pressed against the valve seat to narrow the flow path of the refrigerant, a differential pressure is generated in the refrigerant before and after the control valve, and the first Since the pressure of the outdoor heat exchanger becomes higher than the pressure of the second outdoor heat exchanger and the temperature of the refrigerant flowing through the first outdoor heat exchanger becomes high, frosting of the first heat exchanger can be prevented, A good heating operation can be performed and a separate throttle device is not required.
[Brief description of the drawings]
FIG. 1 is a refrigeration cycle diagram of a refrigeration apparatus showing an embodiment of the present invention.
FIG. 2 is an electric circuit diagram of a valve control device of a refrigeration apparatus showing an embodiment of the present invention.
FIG. 3 is a block diagram of a valve control device of a refrigeration apparatus showing an embodiment of the present invention.
FIG. 4 is a flowchart of a valve control device of a refrigeration apparatus showing an embodiment of the present invention.
FIG. 5 is a refrigeration cycle diagram of a refrigeration apparatus showing another embodiment of the present invention.
FIG. 6 is a sectional view of a control valve used in another refrigeration apparatus of the present invention.
FIG. 7 is a temperature-strain curve diagram of a shape memory alloy spring of a control valve used in another refrigeration apparatus of the present invention.
FIG. 8 is a cross-sectional view showing the operation of a control valve used in another refrigeration apparatus of the present invention.
FIG. 9 is a refrigeration cycle diagram of a refrigeration apparatus showing another embodiment of the present invention.
FIG. 10 is a cross-sectional view of a control valve used in a refrigeration apparatus showing another embodiment of the present invention.
FIG. 11 is a temperature-strain curve diagram of a shape memory alloy spring of a control valve used in a refrigeration apparatus showing another embodiment of the present invention.
FIG. 12 is a sectional view showing the operation of a control valve used in a refrigeration apparatus showing another embodiment of the present invention.
FIG. 13 is a sectional view showing the operation of a control valve used in a refrigeration apparatus showing another embodiment of the present invention.
FIG. 14 is a refrigeration cycle diagram of a refrigeration apparatus showing still another embodiment of the present invention.
FIG. 15 is a sectional view of a control valve used in a refrigeration apparatus showing still another embodiment of the present invention.
FIG. 16 is a cross-sectional view showing the operation of a control valve used in a refrigeration apparatus showing still another embodiment of the present invention.
FIG. 17 is a refrigeration cycle diagram of a refrigeration apparatus showing still another embodiment of the present invention.
FIG. 18 is a cross-sectional view of a control valve used in a refrigeration apparatus showing still another embodiment of the present invention.
FIG. 19 is a cross-sectional view showing the operation of a control valve used in a refrigeration apparatus showing still another embodiment of the present invention.
FIG. 20 is a cross-sectional view showing the operation of a control valve used in a refrigeration apparatus showing still another embodiment of the present invention.
FIG. 21 is a refrigeration cycle diagram of a conventional refrigeration apparatus.
[Explanation of symbols]
  1 Compressor
  2 Four-way valve
  3 Indoor heat exchanger
  4 Aperture device
  5 1st outdoor heat exchanger
  6 Control valve
  7 Second outdoor heat exchanger
  8 Second diaphragm device
  9 Control valve
  10 Disc
  11 Valve seat
  12 Bias spring
  13 First shape memory alloy spring
  14 First flow path
  15 Second bias spring
  16 Second shape memory alloy spring
  17 Stopper
  18 Control valve
  19 Control valve
  20 Second flow path
  21 Control valve
  22 Valve control device
  23 Power switch
  24 Refrigerant temperature detector
  25 A / D converter
  26 Microcomputer (LSI)
  27 Input circuit
  28 CPU
  29 memory
  30 Output circuit
  31 Electromagnetic coil

Claims

Using a non-azeotropic refrigerant mixture, the compressor, the four-way valve, the indoor heat exchanger, the expansion device, the first outdoor heat exchanger, the control valve, and the second outdoor heat exchanger are connected in an annular shape, and the first outdoor heat exchange The second outdoor heat exchanger is made larger than the condenser, and includes a second expansion device provided in parallel with the control valve. The set temperature for opening and closing the control valve is the first set temperature, The value is set smaller as the second set temperature and the third set temperature are reached. When the refrigerant temperature of the first outdoor heat exchanger is lower than the third set temperature, the control valve is opened, and the third set temperature is set. When the temperature is lower than the second set temperature, the control valve is closed, and when the temperature is equal to or higher than the first set temperature, the control valve is opened .

In the refrigeration system using the non-azeotropic refrigerant mixture, the compressor, the four-way valve, the indoor heat exchanger, the expansion device, the first outdoor heat exchanger, the control valve, and the second outdoor heat exchanger are connected in an annular shape. The second outdoor heat exchanger is larger than the outdoor heat exchanger, and includes a pressure reducing mechanism provided in the control valve. The set temperatures for opening and closing the control valve are the first set temperature and the second set temperature. The value is set to be smaller as the temperature becomes the third set temperature, and when the refrigerant temperature of the first outdoor heat exchanger is lower than the third set temperature, the control valve is opened, and the temperature is equal to or higher than the third set temperature. The refrigeration apparatus is configured to close the control valve when the temperature is lower than the second set temperature and to open the control valve when the temperature is equal to or higher than the first set temperature .

The control valve includes a first shape memory alloy spring, a first bias spring, a slidable valve body sandwiched between the first shape memory alloy spring and the first bias spring, a second shape memory alloy spring, The refrigeration apparatus according to claim 1 or 2 , further comprising: a second bias spring, a valve seat sandwiched between the second shape memory alloy spring and the second bias spring .

The temperature hysteresis is 2 to 3 degrees , the transformation temperature during cooling is −2 to −4 ° C., this is the second set temperature, and the transformation temperature during heating is 0 to −2 ° C. and this is the first set temperature. 4. The refrigeration apparatus according to claim 3 , wherein a first shape memory alloy spring and a second shape memory alloy spring having a third set temperature as a transformation temperature during cooling are used as control valves.

The first outdoor heat exchanger refrigerant temperature detecting means for detecting and outputting the refrigerant temperature of the first outdoor heat exchanger, and the comparison for comparing the first outdoor heat exchanger refrigerant temperature and the set temperature and outputting a control signal Storage means storing output mode for controlling the opening and closing of the control valve, selection means for selecting one of the output modes of the storage means based on an output signal generated from the comparison means, and claim 1 Symbol placement of the refrigerating apparatus is characterized in that a valve control device constructed in accordance with the output means for opening and closing said control valve in accordance with the output mode.