JP2002188860A5 - - Google Patents

Description

【書類名】 明細書
【発明の名称】 ヒートポンプ給湯機
【特許請求の範囲】
【請求項１】 圧縮機、冷媒対水熱交換器、冷媒の流量を制御する減圧装置、蒸発器を設けた冷媒循環回路と、貯湯槽、循環ポンプ、前記冷媒対水熱交換器を設けた給湯回路と、前記圧縮機の吐出温度を検出する吐出温度検出手段とを有し、前記圧縮機の吐出温度が給湯運転の効率をよくするように設定された目標吐出温度になるように前記減圧装置の弁開度を制御するヒートポンプ給湯機。
【請求項２】 圧縮機、冷媒対水熱交換器、冷媒の流量を制御する減圧装置、蒸発器を設けた冷媒循環回路と、貯湯槽、循環ポンプ、前記冷媒対水熱交換器を設けた給湯回路と、前記圧縮機の吐出温度を検出する吐出温度検出手段とを有し、前記圧縮機の吐出温度は給湯運転の効率が極大近傍となる目標吐出温度になるように減圧装置の開度を制御するヒートポンプ給湯機。
【請求項３】 圧縮機の起動時は前記減圧装置の弁開度を予め設定された初期弁開度に設定する請求項１または２記載のヒートポンプ給湯機。
【請求項４】 圧縮機が起動する時に、前記圧縮機が温まっている熱時起動と前記圧縮機が冷えている冷時起動とを判断する熱時冷時検出手段と、冷時起動と熱時起動とに応じて、初期弁開度を設定する請求項３記載のヒートポンプ給湯機。
【請求項５】 熱時冷時検出手段は、圧縮機の吐出温度を検出する吐出温度検出手段と外気温度を検出する外気温度検出手段である請求項４記載のヒートポンプ給湯機。
【請求項６】 熱時冷時検出手段は、圧縮機の高圧側の温度を検出する圧縮機温度検出手段である請求項４記載のヒートポンプ給湯機。
【請求項７】 熱時冷時検出手段は、前回の運転停止からの経過時間を計測する時間計測手段と外気温度を検出する外気温度検出手段である請求項４記載のヒートポンプ給湯機。
【請求項８】 外気温度を検出する外気温度検出手段からの信号に応じて、初期弁開度を設定する請求項３記載のヒートポンプ給湯機。
【請求項９】 冷媒対水熱交換器の水側入口水温である給水温度を検出する給水温度検出手段からの信号に応じて、初期弁開度を設定する請求項３記載のヒートポンプ給湯機。
【請求項１０】 冷媒対水熱交換器の水側入口水温である給水温度を検出する給水温度検出手段からの信号と外気温度を検出する外気温度検出手段からの信号とに応じて、初期弁開度を設定する請求項３記載のヒートポンプ給湯機。
【請求項１１】 外気温度を検出する外気温度検出手段からの信号に応じて、目標吐出温度を設定する請求項１または２記載のヒートポンプ給湯機。
【請求項１２】 冷媒対水熱交換器の水側入口水温である給水温度を検出する給水温度検出手段からの信号に応じて、目標吐出温度を決定する制御手段を備えていること特徴とする請求項１または２記載のヒートポンプ給湯機。
【請求項１３】 冷媒対水熱交換器の水側出口水温である沸き上げ温度の到達目標温度である目標沸き上げ温度に応じて、目標吐出温度を決定する制御手段を備えていること特徴とする請求項１または２記載のヒートポンプ給湯機。
【請求項１４】 冷媒は二酸化炭素であることを特徴とする請求項１〜１３いずれか１項に記載のヒートポンプ給湯機。
【発明の詳細な説明】
【０００１】
【発明の属する技術分野】
本発明は貯湯式のヒートポンプ給湯機に関するものである。
【０００２】
【従来の技術】
従来のこの種のヒートポンプ給湯機は特開昭６０−１６４１５７号公報に示すようなものがある。図２８は従来のヒートポンプ給湯機の構成図である。図２８において、圧縮機１、冷媒対水熱交換器２、減圧装置３、蒸発器４からなる冷媒循環回路と、貯湯槽５、循環ポンプ６、前記冷媒対水熱交換器２、補助加熱器７を接続した給湯回路ならなり前記圧縮機１より吐出された高温高圧の過熱ガス冷媒は前記冷媒対水熱交換器２に流入し、ここで前記循環ポンプ６から送られてきた水を加熱する。そして、この水と熱交換した冷媒は前記減圧装置３で減圧され、前記蒸発器４に流入し、ここで大気熱を吸熱して蒸発ガス化し、前記圧縮機１に戻る。一方、前記冷媒対水熱交換器２で加熱された湯は前記貯湯槽５の上部に流入し、上から次第に貯湯されていく。そして、前記冷媒対水熱交換器２の入口水温が設定値に達すると給水温度検出手段８が検知し、前記圧縮機１によるヒートポンプ運転を停止して、前記補助加熱器７の単独運転に切り換えるものである。
【０００３】
【発明が解決しようとする課題】
上記図２８に示す従来例のヒートポンプ給湯機では、減圧装置３としてキャピラリーチューブや温度式膨張弁を用いていた。減圧装置３としてキャピラリーチューブを用いる場合、一般的に、冷媒循環量の多い夏季の温度条件を基準にキャピラリーチューブの仕様を設計する。そのため、夏季以外の特に冬季の運転開始時には、必要以上に冷媒が流れるので、圧縮機１の温度上昇が遅く、冷媒対水熱交換器２出口の湯は低温のまま貯湯槽５の上部に流入し貯湯される。それ故、貯湯槽５の中の高温の湯と混合し、貯湯槽５の湯温を低下させてしまい、時としては、湯切れを起こすという課題があった。また、圧縮機１の温度が上昇した後の定常運転時にも、同様に、冷媒循環回路に必要以上の冷媒が循環するため、運転の効率が悪くなるという課題を有していた。さらに場合によっては、圧縮機１に液冷媒が吸い込まれ、その結果、液圧縮となり圧縮機１の耐久性が悪くなるという課題も有していた。
【０００４】
他方、減圧装置３として温度式膨張弁を用いる場合、一般的に、蒸発器４の出口の冷媒は一定の過熱度がとれた過熱ガス状態となるように、減圧装置３としての温度式膨張弁の仕様を設計する。しかし、運転開始時には冷媒回路中の冷媒の分布が安定しないため、圧縮機１の吐出圧力や吐出温度がハンチング（上下変動）し、上限吐出圧力や上限吐出温度を超える場合があり、圧縮機１の耐久性が悪くなるという課題を有していた。また、定常運転時においても、設計した外気温度よりも高い時には吐出圧力が上昇したり、外気温度の低い冬季には吐出温度が上昇したりして圧縮機の耐久性が悪くなるという課題を有していた。
【０００５】
本発明の目的は、湯切れが少なく、効率の良い給湯加熱運転を実現することにある。
【０００６】
【課題を解決するための手段】
前記従来の課題を解決するために、本発明のヒートポンプ給湯機は、圧縮機、冷媒対水熱交換器、冷媒の流量を制御する減圧装置、蒸発器を設けた冷媒循環回路と、貯湯槽、循環ポンプ、前記冷媒対水熱交換器を設けた給湯回路と、前記圧縮機の吐出温度を検出する吐出温度検出手段とを有し、前記圧縮機の吐出温度が給湯運転の効率をよくするように設定された目標吐出温度になるように前記減圧装置の弁開度を制御するものである。
【０００７】
これによって、目標吐出温度になるように前記減圧装置の弁開度を制御するため、常に冷媒回路に適正な冷媒が循環し、圧力と温度とも安定することになる。
【０００８】
【発明の実施の形態】
本発明は各請求項に記載の形態で実施できるものであり、請求項１記載の発明は、圧縮機、冷媒対水熱交換器、冷媒の流量を制御する減圧装置、蒸発器を設けた冷媒循環回路と、貯湯槽、循環ポンプ、前記冷媒対水熱交換器を設けた給湯回路と、前記圧縮機の吐出温度を検出する吐出温度検出手段とを有し、前記圧縮機の吐出温度が給湯運転の効率をよくするように設定された目標吐出温度になるように前記減圧装置の弁開度を制御するようにしており、また、請求項２記載の発明は、圧縮機、冷媒対水熱交換器、冷媒の流量を制御する減圧装置、蒸発器を設けた冷媒循環回路と、貯湯槽、循環ポンプ、前記冷媒対水熱交換器を設けた給湯回路と、前記圧縮機の吐出温度を検出する吐出温度検出手段とを有し、前記圧縮機の吐出温度は給湯運転の効率が極大近傍となる目標吐出温度になるように減圧装置の開度を制御するようにしているため、常に冷媒回路に適正な冷媒が循環するので、運転効率を良くすることができる。
【０００９】
請求項３記載の発明は、前記圧縮機の起動時には前記減圧装置の弁開度を予め設定された初期弁開度に設定する制御手段を具備することにより、運転の起動時にも、冷媒回路に適正な冷媒が循環するので、前記圧縮機の吐出温度や吐出圧力のハンチングによる異常温度上昇や異常圧力上昇がなく耐久性が高く、また、圧縮機の温度上昇が速く、すぐに冷媒対水熱交換器出口の湯は高温となるので、湯切れの可能性も少くすることができる。
【００１０】
請求項４記載の発明は、前記圧縮機が起動する時に、前記圧縮機が温まっている熱時起動と前記圧縮機が冷えている冷時起動とを判断する熱時冷時検出手段と、冷時起動と熱時起動とに応じて初期弁開度を決定する制御手段とを具備することにより、前記圧縮機の初期温度に応じた前記減圧装置の弁開度を設定するため、運転起動時にも冷媒回路に適正な冷媒が循環するので、特に冷時においても圧縮機の温度上昇が速く、すぐに冷媒対水熱交換器出口の湯は高温となるので、湯切れの可能性も少くすることができる。
【００１１】
請求項５記載の発明は、熱時冷時検出手段として、前記圧縮機の吐出温度を検出する吐出温度検出手段と外気温度を検出する外気温度検出手段とを具備することにより、外気温度が変化してもその外気温度に対して、前記圧縮機の初期温度に応じた前記減圧装置の弁開度を設定するため、運転起動時にも冷媒回路に適正な冷媒が循環するので、特に冷時においても圧縮機の温度上昇が速く、すぐに冷媒対水熱交換器出口の湯は高温となるので、湯切れの可能性も少くすることができる。
【００１２】
請求項６の発明は、熱時冷時検出手段として、前記圧縮機の高圧側の温度を検出する圧縮機温度検出手段を具備することにより、上記のように、直接前記圧縮機の温度を検出するため、熱時冷時判定のための待機時間が無く、運転起動と同時に前記減圧装置の弁開度を最適値に設定できるので、運転効率を良くすることができる。
【００１３】
請求項７の発明は、熱時冷時検出手段として、前回の運転停止からの経過時間を計測する時間計測手段と外気温度を検出する外気温度検出手段とを具備することにより、前回の運転停止からの経過時間と外気温度とから熱時と冷時の判断を行うので、運転起動と同時に判断ができ、外気温度が変化しても常に運転効率を良くすることができる。
【００１４】
請求項８の発明は、外気温度を検出する前記外気温度検出手段からの信号に応じて、初期弁開度を決定する制御手段を具備することにより、外気温度に対して前記減圧装置の初期弁開度を設定するため、外気温度が変化しても運転の起動時に適正な冷媒が循環するので、前記圧縮機の吐出温度や吐出圧力のハンチングによる異常温度上昇や異常圧力上昇がなく耐久性が高く、また、圧縮機の温度上昇が速く、すぐに冷媒対水熱交換器出口の湯は高温となるので、湯切れの可能性も少くすることができる。
【００１５】
請求項９の発明は、前記冷媒対水熱交換器の水側入口水温である給水温度を検出する給水温度検出手段からの信号に応じて、初期弁開度を決定する制御手段を具備することにより、貯湯槽の湯水混合層領域の湯も沸き上げることができ、そのため、貯湯槽の湯容積を有効に利用できるので、湯切れの可能性も少くすることができる。
【００１６】
請求項１０の発明は、前記冷媒対水熱交換器の水側入口水温である前記給水温度を検出する前記給水温度検出手段からの信号と外気温度を検出する前記外気温度検出手段からの信号とに応じて、初期弁開度を決定する制御手段を具備することにより、貯湯槽の湯水混合層領域の湯も沸き上げることができ、そのため、外気温度が変化しても常に貯湯槽の湯容積を有効に利用できるので、湯切れの可能性も少くすることができる。
【００１７】
請求項１１の発明は、外気温度を検出する前記外気温度検出手段からの信号に応じて、目標吐出温度を決定する制御手段を具備することにより、目標吐出温度になるように前記減圧装置の弁開度を制御するため、外気温度が変化しても常に冷媒回路に適正な冷媒が循環するので、異常温度上昇や異常圧力上昇がなく、耐久性が高く、運転効率も良くすることができる。
【００１８】
請求項１２の発明は、前記冷媒対水熱交換器の水側入口水温である給水温度を検出する前記給水温度検出手段からの信号に応じて、目標吐出温度を決定する制御手段を具備することにより、給水温度が高くなった時に目標吐出温度を低く設定し、さらに、この低く設定した目標吐出温度になるように前記減圧装置の弁開度を制御するため、給水温度が変化しても常に冷媒回路に適正な冷媒が循環するので、異常温度上昇や異常圧力上昇がなく、耐久性が高く、運転効率も良くすることができる。
【００１９】
請求項１３の発明は、冷媒対水熱交換器の水側出口水温である沸き上げ温度の到達目標温度である目標沸き上げ温度に応じて、目標吐出温度を決定する制御手段を具備することにより、目標吐出温度になるように前記減圧装置の弁開度を制御するため、目標沸き上げ温度を変更しても常に冷媒回路に適正な冷媒が循環するので、異常温度上昇や異常圧力上昇がなく、耐久性が高く、運転効率も良くすることができる。また、請求項１４の発明は、冷媒は二酸化炭素であることを特徴とするものである。
【００２０】
【実施例】
以下、本発明の実施例について図面を用いて説明する。
【００２１】
（実施例１）
図１は本発明の実施例１のヒートポンプ給湯機の構成図、図２は同ヒートポンプ給湯機の減圧装置の開度に対する吐出温度と吐出圧力と効率を示す説明図である。なお、従来例で説明した図２８と同じ構成部材には同一符号を用い説明を省略する。
【００２２】
図１において、冷媒対水熱交換器２の水側出口に設けられた沸き上げ温度検出手段９からの信号で回転数制御手段１０は循環ポンプ６の回転数を制御して、冷媒対水熱交換器２の出口水温（沸き上げ温度）をほぼ一定になるように沸き上げる。また、制御手段１１は、目標吐出温度を記憶している目標吐出温度記憶手段１２と圧縮機１の吐出温度を検出する吐出温度検出手段１３からの信号で減圧装置３を制御する。なお、減圧装置３として電動膨張弁（図示せず）等がある。
【００２３】
次に動作、作用について説明する。図２は横軸に減圧装置３の弁開度をとり、縦軸に吐出温度と吐出圧力と効率をとって、ある外気温度の時の減圧装置３の弁開度に対する吐出温度と吐出圧力と効率の関係を示したものである。同図からわかるように、効率は減圧装置３の弁開度に対して極大値がある。また、同図において、一点鎖線は圧縮機の通常使用時の上限吐出温度（常用最大吐出温度）であり、二点鎖線は圧縮機の通常使用時の上限吐出圧力（常用最大吐出圧力）である。
【００２４】
ここで、効率が極大になる減圧装置３の弁開度Ｘに対する吐出温度を目標吐出温度Ｙとする。この目標吐出温度Ｙを目標吐出温度記憶手段１２に予め記憶させる。
【００２５】
つまり、給湯運転が始まり圧縮機１が起動すると、制御手段１１は吐出温度検出手段１３からの信号で吐出温度を検出する。そして、目標吐出温度を記憶している目標吐出温度記憶手段１２からの情報で、今の吐出温度が目標吐出温度よりも高ければ、制御手段１１は減圧装置３の弁開度を大きくする（開く）ように制御する。逆に、今の吐出温度が目標吐出温度よりも低ければ、制御手段１１は減圧装置３の弁開度を小さくする（閉じる）ように制御する。
【００２６】
上記のように、制御手段１１による吐出温度制御をある時間毎に行えば、常に効率の良い給湯運転が可能となる。また、目標吐出温度になるように減圧装置３の弁開度を制御するため、常に冷媒回路に適正な冷媒が循環するので、異常温度上昇や異常圧力上昇がなく、耐久性も良くすることができる。
【００２７】
（実施例２）
図３は本発明の実施例２のヒートポンプ給湯機の構成図、図４は同ヒートポンプ給湯機の運転時間に対する吐出温度を示す説明図である。
【００２８】
本実施例において、実施例１と異なる点は、運転起動時における減圧装置３の弁開度を記憶している初期弁開度記憶手段１４を設けた構成としていることである。なお、実施例１と同符号の部分は同一構成を有し、説明は省略する。
【００２９】
次に動作、作用について説明する。図３において、運転起動時には、制御手段１１は、起動時における減圧装置３の弁開度（初期弁開度）を記憶している初期弁開度記憶手段１４からの信号で減圧装置３の弁開度を前記初期弁開度に設定した後、給湯加熱運転を開始する。
【００３０】
図４は横軸に運転時間をとり、縦軸に吐出温度をとって、運転時間に対する吐出温度変化を示したものである。同図において、Ｔｇは目標吐出温度である。また、Ｔｄ０は制御開始吐出温度で、吐出温度がこの温度になるまでは減圧装置３の弁開度は初期弁開度で一定とし、吐出温度がこの制御開始吐出温度Ｔｄ０以上になれば、実施例１で説明したように、吐出温度制御運転を行う。すなわち、制御手段１１は吐出温度検出手段１３からの信号で吐出温度を検出する。そして、目標吐出温度を記憶している目標吐出温度記憶手段１２からの情報で、今の吐出温度が目標吐出温度よりも高ければ、制御手段１１は減圧装置３の弁開度を大きくする（開く）ように制御する。逆に、今の吐出温度が目標吐出温度よりも低ければ、制御手段１１は減圧装置３の弁開度を小さくする（閉じる）ように制御する。
【００３１】
今、図４において、吐出温度が目標吐出温度に達して、定常状態になった時の減圧装置３の弁開度を到達弁開度とする。同図において、実線Ａは運転起動から減圧装置３の弁開度を到達弁開度で運転した場合の吐出温度の変化を示したものである。もし、この到達弁開度よりも小さい（閉じた）弁開度で運転した場合は、一点鎖線Ｂのようになり、吐出温度がハンチング（上下変動）し、場合によっては上限吐出温度を超えることもある。逆に、この到達弁開度よりも大きい（開いた）弁開度で運転した場合は、点線Ｃのようになり、吐出温度の上昇が遅く、目標吐出温度に達するのに時間がかかる。
【００３２】
そこで、この到達弁開度である弁開度Ｚを予め求めておいて、初期弁開度記憶手段１４に記憶させておく。給湯運転の起動時に、制御手段１１は初期弁開度記憶手段１４からの信号で減圧装置３の初期弁開度（弁開度Ｚ）を求める。そして、制御手段１１は減圧装置３の弁開度を弁開度Ｚに設定した後、給湯加熱運転を開始する。
【００３３】
上記のように、運転の起動時に減圧装置３の弁開度を予め設定された初期弁開度に設定することにより、冷媒回路に適正な冷媒が循環するので、圧縮機１の吐出温度や吐出圧力のハンチングによる異常温度上昇や異常圧力上昇がなく耐久性が高く、また、圧縮機１の吐出温度上昇が速く、すぐに冷媒対水熱交換器２出口の湯は高温となるので、湯切れの可能性も少くすることができる。
【００３４】
（実施例３）
図５は本発明の実施例３のヒートポンプ給湯機の構成図、図６は同ヒートポンプ給湯機の運転時間に対する吐出温度を示す説明図である。
【００３５】
本実施例において、実施例２と異なる点は、圧縮機１が温まっている熱時起動と圧縮機１が冷えている冷時起動とを検出する熱時冷時検出手段１５を備えた構成としていることである。ここでは、熱時冷時検出手段１５として吐出温度検出手段１３を用いる。なお、実施例２と同符号の部分は同一構成を有し、説明は省略する。
【００３６】
次に動作、作用について説明する。図６は横軸に運転時間をとり、縦軸に吐出温度をとって、運転時間に対する吐出温度の変化を示したものである。同図において、Ｔｇは目標吐出温度である。また、Ｔｄ０は制御開始吐出温度で、吐出温度がこの温度になるまでは減圧装置３の弁開度は初期弁開度で一定とし、吐出温度がこの制御開始吐出温度Ｔｄ０以上になれば、実施例１で説明したように、吐出温度制御運転を行う。同図の実線で示す吐出温度の変化は、運転起動時に圧縮機１が温まっている熱時起動の場合であり、一点鎖線で示す吐出温度の変化は、運転起動時に圧縮機１が冷えている冷時起動の場合である。同図からわかるように、熱時起動の場合は立ち上がりが速く、すぐに定常状態になる。一方、冷時起動の場合は立ち上がりが遅く、定常状態に達するまでに時間がかかる。熱時起動の場合も冷時起動の場合も、定常状態に達したときの減圧装置３の弁開度（実施例２で説明した弁開度Ｚ）は同じである。冷時起動の立ち上がりを速くするために、冷時起動の場合は、熱時起動の場合よりも、減圧装置３の初期弁開度を小さく設定する。そうすれば、同図中の点線（冷時の改良）で示すように、吐出温度の立ち上がりが比較的速くなる。
【００３７】
図６において、Ｔｊｄを熱時起動と冷時起動との区別を判定する熱時冷時判定吐出温度とし、運転起動して所定の待機時間ｔ後にこの熱時起動と冷時起動との区別を判定するものとする。すなわち、給湯運転の起動時に、制御手段１１は初期弁開度記憶手段１４からの信号で減圧装置３の初期弁開度（弁開度Ｚ）を求める。そして、制御手段１１は減圧装置３の弁開度を弁開度Ｚに設定した後、給湯加熱運転を開始する。そして、起動して所定の待機時間ｔ後、吐出温度検出手段１３からの信号から得た吐出温度が、熱時冷時判定吐出温度Ｔｊｄ以上の温度（点Ａ）であれば熱時起動と判定し、熱時冷時判定吐出温度Ｔｊｄより低い温度（点Ｂ）であれば冷時起動と判定する。判定の結果、熱時起動の場合にはそのままの弁開度（弁開度Ｚ）で運転を続ける。一方、冷時起動の場合には、制御手段１１は減圧装置３の弁開度を弁開度Ｚより小さい弁開度（弁開度Ｚｍ）に設定し運転を続ける。なお、この弁開度Ｚｍは、吐出温度の大きなオーバーシュートが無い範囲で予め求めておく。そして、熱時起動の場合も冷時起動の場合も、吐出温度が制御開始吐出温度Ｔｄ０以上になれば、実施例１で説明したように、吐出温度制御運転を行う。すなわち、制御手段１１は吐出温度検出手段１３からの信号で吐出温度を検出する。そして、目標吐出温度を記憶している目標吐出温度記憶手段１２からの情報で、今の吐出温度が目標吐出温度よりも高ければ、制御手段１１は減圧装置３の弁開度を大きくする（開く）ように制御する。逆に、今の吐出温度が目標吐出温度よりも低ければ、制御手段１１は減圧装置３の弁開度を小さくする（閉じる）ように制御する。
【００３８】
上記のように、圧縮機１の起動時の温度に応じて減圧装置３の弁開度を設定するため、運転起動時にも冷媒回路に適正な冷媒が循環するので、特に冷時においても圧縮機１の温度上昇が速く、すぐに冷媒対水熱交換器２出口の湯は高温となるので、湯切れの可能性も少くすることができる。
【００３９】
（実施例４）
図７は本発明の実施例４のヒートポンプ給湯機の構成図、図８は同ヒートポンプ給湯機の運転停止後の圧縮機の温度に対する吐出温度検出手段を付けている配管の温度を示す説明図である。
【００４０】
本実施例において、実施例３と異なる点は、熱時冷時検出手段１５として吐出温度検出手段１３と外気温度検出手段１６とを用いた構成としていることである。なお、実施例３と同符号の部分は同一構成を有し、説明は省略する。
【００４１】
次に動作、作用について説明する。図８は横軸に運転停止後の圧縮機１の温度をとり、縦軸に吐出温度検出手段１３を付けている配管の温度をとって、運転停止後の圧縮機１の温度に対する吐出温度検出手段１３を付けている配管の温度変化の関係を示したものである。いま、吐出温度を検出する吐出温度検出手段１３は圧縮機１の吐出口に接続された配管に設けられている。運転中は冷媒が循環しているため、圧縮機１の温度と吐出温度検出手段１３の取り付けている配管部の温度とはほぼ等しいが、運転を停止すると、圧縮機１の温度と吐出温度検出手段１３の取り付けている配管部の温度とは差ができてくる。すなわち、圧縮機１は熱容量が吐出温度検出手段１３の取り付けている配管よりも大きく、さらに、圧縮機１は通常、防音のため断熱材で覆われている。このため、圧縮機１の温度低下の速さは吐出温度検出手段１３の取り付けている配管の温度低下の速さよりも小さい。また、温度の低下の速さは外気温度によっても異なる。当然、外気温度が低いほど温度の低下の速さは大きい。
【００４２】
同図において、Ｔｇは目標吐出温度であり、Ｔｊは熱時起動と冷時起動との区別を判定する熱時冷時判定圧縮機温度である。つまり、運転起動時に、圧縮機１の温度が、Ｔｊ以上であれば熱時起動であり、Ｔｊより小さければ冷時起動である。また、実線は夏（例えば外気温度３５゜Ｃ）における運転停止後の圧縮機１の温度と吐出温度検出手段１３を取り付けている配管の温度との関係を示したものである。同様に、一点鎖線および点線はそれぞれ中間期（例えば外気温度２０゜Ｃ）及び冬（例えば外気温度５゜Ｃ）における関係を示している。夏、中間期、冬における前述した関係において、運転停止後の圧縮機１の温度が熱時冷時判定圧縮機温度Ｔｊになる時の吐出温度検出手段１３を取り付けている配管の温度はそれぞれＴ１、Ｔ２、Ｔ３となる。そして、この外気温度（例えば３５゜Ｃ、２０゜Ｃ、５゜Ｃ）に対して、Ｔ１、Ｔ２、Ｔ３を予め求めておけば、吐出温度検出手段１３からの信号によって、熱時起動か冷時起動かの判断ができる。
【００４３】
上記のように、外気温度が変化してもその外気温度に対して、圧縮機１の初期温度に応じた減圧装置３の弁開度を設定するため、運転起動時にも冷媒回路に適正な冷媒が循環するので、特に冷時においても圧縮機の温度上昇が速く、すぐに冷媒対水熱交換器出口の湯は高温となるので、湯切れの可能性も少くすることができる。
【００４４】
（実施例５）
図９は本発明の実施例５のヒートポンプ給湯機の構成図である。本実施例において、実施例３と異なる点は、熱時冷時検出手段１５として圧縮機温度検出手段１７を用いた構成としていることである。なお、実施例３と同符号の部分は同一構成を有し、説明は省略する。
【００４５】
次に動作、作用について説明する。実施例４で説明したように、熱時起動と冷時起動との区別を判定する圧縮機１の温度を熱時冷時判定圧縮機温度Ｔｊとすると、運転起動時に、圧縮機１の温度が、Ｔｊ以上であれば熱時起動であり、Ｔｊより小さければ冷時起動である。
【００４６】
すなわち、給湯運転の起動時に、制御手段１１は圧縮機温度検出手段１７からの信号で圧縮機１の温度を求める。そして、この求めた温度が前述した熱時冷時判定圧縮機温度Ｔｊよりも大きいか等しければ、制御手段１１は熱時起動と判断し、減圧装置３の弁開度を弁開度Ｚに設定した後、給湯加熱運転を開始する。逆に求めた温度が前述した熱時冷時判定圧縮機温度Ｔｊよりも小さければ、制御手段１１は冷時起動と判断し、減圧装置３の弁開度を弁開度Ｚより小さい弁開度（弁開度Ｚｍ）に設定した後、給湯加熱運転を開始する。
【００４７】
上記のように、直接圧縮機１の温度を検出するため、熱時冷時判定のための待機時間が無く、運転起動と同時に減圧装置３の弁開度を最適値に設定できるので、運転効率を良くすることができる。
【００４８】
（実施例６）
図１０は本発明の実施例６のヒートポンプ給湯機の構成図、図１１は同ヒートポンプ給湯機の運転停止後の時間に対する吐出温度検出手段１３を付けている配管の温度を示す説明図、図１２は同ヒートポンプ給湯機の外気温度に対する熱時冷時判定時間を示す説明図である。
【００４９】
本実施例において、実施例３と異なる点は、熱時冷時検出手段１５として前回の運転停止からの経過時間を計測する時間計測手段１８と外気温度を検出する外気温度検出手段１６とを用いた構成としていることである。なお、実施例３と同符号の部分は同一構成を有し、説明は省略する。
【００５０】
次に動作、作用について説明する。図１１は横軸に運転停止後の時間をとり、縦軸に吐出温度検出手段１３を付けている配管の温度をとって、運転停止後の時間に対する吐出温度検出手段１３を付けている配管の温度の変化の関係を示したものである。同図において、Ｔｇは目標吐出温度であり、Ｔｊｈは熱時起動と冷時起動との区別を判定する熱時冷時判定吐出配管温度である。いま、吐出温度を検出する吐出温度検出手段１３は圧縮機１の吐出口に接続された配管に設けられている。そして、運転を停止すると圧縮機１の温度が低下するとともに、吐出温度検出手段１３を付けている配管の温度も低下する。また、温度の低下の速さは外気温度によっても異なる。当然、外気温度が低いほど温度の低下の速さは大きい。同図において、実線は、夏（例えば外気温度３５゜Ｃ）の場合における、運転停止後の時間に対する吐出温度検出手段１３を付けている配管の温度の変化を示す。同様に、一点鎖線および点線はそれぞれ中間期（例えば外気温度２０゜Ｃ）及び冬（例えば外気温度５゜Ｃ）における吐出温度検出手段１３を付けている配管の温度の変化を示す。また、吐出温度検出手段１３を付けている配管の温度が、熱時起動と冷時起動との区別を判定する熱時冷時判定吐出配管温度Ｔｊｈ以上であれば熱時起動であり、熱時冷時判定吐出配管温度Ｔｊｈ未満であれば冷時起動である。夏、中間期、冬における吐出温度検出手段１３を付けている配管の温度が熱時冷時判定吐出配管温度Ｔｊｈに等しくなる運転停止後の時間はそれぞれｔ１、ｔ２、ｔ３となる。この時間を熱時冷時判定時間とする。つまり、運転を起動する場合に、前回の運転停止後からの時間が、この熱時冷時判定時間以下であれば熱時起動であり、この熱時冷時判定時間より大きければ冷時起動となる。
【００５１】
図１２は横軸に外気温度をとり、縦軸に熱時冷時判定時間をとって、外気温度に対する熱時冷時判定時間の関係を示したものである。同図において、実線よりしたの部分が熱時起動で、上の部分が冷時起動である。この図１２の関係を予め求めておくことによって、時間計測手段１８からの信号と外気温度検出手段１６とによって、熱時起動か冷時起動かの判断ができる。
【００５２】
すなわち、給湯運転の起動時に、制御手段１１は、時間計測手段１８からの信号で前回の運転停止からの経過時間を求め、さらに、外気温度検出手段１６からの信号で外気温度を求める。そして、この求めた外気温度おいて、前回の運転停止からの経過時間が前述の熱時冷時判定時間以下であれば、制御手段１１は熱時起動と判断し、減圧装置３の弁開度を弁開度Ｚに設定した後、給湯加熱運転を開始する。逆に前回の運転停止からの経過時間が前述の熱時冷時判定時間より大きければ、制御手段１１は冷時起動と判断し、減圧装置３の弁開度を弁開度Ｚより小さい弁開度（弁開度Ｚｍ）に設定した後、給湯加熱運転を開始する。
【００５３】
上記のように、前回の運転停止からの経過時間と外気温度とから熱時と冷時の判断を行うので、運転起動と同時に判断ができ、外気温度が変化しても常に運転効率を良くすることができる。
【００５４】
（実施例７）
図１３は本発明の実施例７のヒートポンプ給湯機の構成図、図１４は同ヒートポンプ給湯機の外気温度に対する減圧装置の弁開度と冷媒循環量とを示す説明図である。
【００５５】
本実施例において、実施例２と異なる点は、外気温度検出手段１６からの信号に応じて減圧装置３の初期弁開度を決定する制御手段１１を設けた構成としていることである。なお、実施例２と同符号の部分は同一構成を有し、説明は省略する。
【００５６】
次に動作、作用について説明する。図１４は横軸に外気温度をとり、縦軸に冷媒循環量と減圧装置３の弁開度とをとって、外気温度に対する冷媒循環量と減圧装置３の弁開度の変化を示したものである。一般に、外気温度が高くなると、蒸発器４が大気熱から得るエネルギーは大きくなる。それに従って、同図に示すように、冷媒循環量が増加するので、圧縮機１の吐出温度と吐出圧力とを上限吐出温度および上限吐出圧力以下にするためには、減圧装置３の弁開度を大きく（開く）する必要がある。
【００５７】
そこで、実施例２で説明した到達弁開度である弁開度Ｚを、外気温度に対して予め求めておいて、初期弁開度記憶手段１４に記憶させておく。給湯運転の起動時に、制御手段１１は外気温度検出手段１６からの信号と初期弁開度記憶手段１４からの信号とで減圧装置３の初期弁開度（弁開度Ｚ）を求める。そして、制御手段１１は減圧装置３の弁開度を弁開度Ｚに設定した後、給湯加熱運転を開始する。
【００５８】
上記のように、外気温度に対して減圧装置３の初期弁開度を設定するため、外気温度が変化しても運転の起動時に適正な冷媒が循環するので、圧縮機１の吐出度や吐出圧力のハンチングによる異常温度上昇や異常圧力上昇がなく耐久性が高く、また、圧縮機１の温度上昇が速く、すぐに冷媒対水熱交換器２出口の湯は高温となるので、湯切れの可能性も少くすることができる。
【００５９】
（実施例８）
図１５は本発明の実施例８のヒートポンプ給湯機の構成図、図１６は同ヒートポンプ給湯機の貯湯槽の高さ方向に対する貯湯槽内の湯の温度を示す説明図、図１７は同ヒートポンプ給湯機の給水温度に対する吐出圧力を示す説明図、図１８は同ヒートポンプ給湯機の給水温度に対する減圧装置の弁開度を示す説明図である。
【００６０】
本実施例において、実施例２と異なる点は、冷媒対水熱交換器２の水側入口水温である給水温度を検出する給水温度検出手段８からの信号に応じて、初期弁開度を決定する制御手段１１を設けた構成としていることである。なお、実施例２と同符号の部分は同一構成を有し、説明は省略する。
【００６１】
次に動作、作用について説明する。図１６は横軸に貯湯槽５内の湯の温度をとり、縦軸に貯湯槽５の高さをとって、貯湯槽内の湯の温度分布を示したものである。前述したように、冷媒対水熱交換器２の水側出口に設けられた沸き上げ温度検出手段９からの信号で回転数制御手段１０は循環ポンプ６の回転数を制御して、冷媒対水熱交換器２の出口水温（沸き上げ温度）をほぼ一定になるように沸き上げる。しかしながら、沸き上げ運転時間の経過とともに貯湯槽５内の高温湯と低温水の接する部分で高温湯と低温水が混合した混合層が生じ、その層は次第に拡大していく。同図中において、前述の混合層は、高温湯と低温湯の熱伝導および対流により発生するものであり、高温湯から低温湯へ伝熱されその境界部分で高温湯は温度低下し、逆に低温湯は温度上昇する。従って、沸き上げ運転完了近くになると、前記冷媒対水熱交換器２に流入する水温は、時間とともに急激に高くなる。図１７は横軸に冷媒対水熱交換器２の水側入口水温である給水温度をとり、縦軸に吐出圧力をとって、減圧装置３の弁開度をパラメータとして、給水温度に対する吐出圧力の関係を示したものである。同図からわかるように、給水温度が高くなるほど吐出圧力も高くなるが、同一の給水温度に対しては、減圧装置３の弁開度が大きい方が、吐出圧力が低くなる。いま、設計吐出圧力をＰｓとすると、減圧装置３の弁開度大、中、小に対して、設計吐出圧力Ｐｓになる給水温度は、それぞれ、Ｔｗ１、Ｔｗ２、Ｔｗ３となる。さらに、図１８はこの関係を給水温度と減圧装置３の弁開度について表したものである。すなわち、横軸に冷媒対水熱交換器２の水側入口水温である給水温度をとり、縦軸に減圧装置３の弁開度をとって、給水温度に対する減圧装置３の弁開度の関係を示したものである。
【００６２】
そこで、実施例２で説明した到達弁開度である弁開度Ｚを、給水温度に対して予め求めておいて、初期弁開度記憶手段１４に記憶させておく。給湯運転の起動時に、制御手段１１は給水温度検出手段８からの信号と初期弁開度記憶手段１４からの信号とで減圧装置３の初期弁開度（弁開度Ｚ）を求める。そして、制御手段１１は減圧装置３の弁開度を弁開度Ｚに設定した後、給湯加熱運転を開始する。
【００６３】
上記のように、給水温度に応じて初期弁開度を設定するため、貯湯槽５の湯水混合層領域の湯も沸き上げることができ、そのため、貯湯槽５の湯容積を有効に利用できるので、湯切れの可能性も少くすることができる。
【００６４】
（実施例９）
図１９は本発明の実施例９のヒートポンプ給湯機の構成図、図２０は同ヒートポンプ給湯機の給水温度に対する吐出圧力を示す説明図、図２１は同ヒートポンプ給湯機の給水温度に対する減圧装置の弁開度を示す説明図である。
【００６５】
本実施例において、実施例２と異なる点は、冷媒対水熱交換器２の水側入口水温である給水温度を検出する給水温度検出手段８からの信号と外気温度を検出する外気温度検出手段１６からの信号とに応じて、初期弁開度を決定する制御手段１１を設けた構成としていることである。なお、実施例２と同符号の部分は同一構成を有し、説明は省略する。
【００６６】
次に動作、作用について説明する。図２０は横軸に冷媒対水熱交換器２の水側入口水温である給水温度をとり、縦軸に吐出圧力をとって、外気温度（例えば夏３５゜Ｃ、中間期２０゜Ｃ、冬５゜Ｃ）をパラメータとして、減圧装置３の弁開度を一定とした場合の給水温度に対する吐出圧力の関係を示したものである。同図からわかるように、蒸発器４が大気熱から得るエネルギー（夏＞中間期＞冬）が大きい方が、吐出圧力が高くなる。いま、図２０において、各外気温度（夏、中間期、冬）に対して、図１７で説明したことが成り立つ。さらに、図１８で説明した給水温度と減圧装置３の弁開度との関係を、各外気温度（夏、中間期、冬）に対して、求めれば図２１のようになる。すなわち、図２１は、横軸に冷媒対水熱交換器２の水側入口水温である給水温度をとり、縦軸に減圧装置３の弁開度をとって、外気温度（例えば夏３５゜Ｃ、中間期２０゜Ｃ、冬５゜Ｃ）をパラメータとして、給水温度に対する減圧装置３の弁開度の関係を示したものである。
【００６７】
そこで、実施例２で説明した到達弁開度である弁開度Ｚを、外気温度をパラメータとして、給水温度に対して予め求めておいて、初期弁開度記憶手段１４に記憶させておく。給湯運転の起動時に、制御手段１１は給水温度検出手段８からの信号と外気温度検出手段１６からの信号と初期弁開度記憶手段１４からの信号とで減圧装置３の初期弁開度（弁開度Ｚ）を求める。そして、制御手段１１は減圧装置３の弁開度を弁開度Ｚに設定した後、給湯加熱運転を開始する。
【００６８】
上記のように、給水温度と外気温度とに応じて、初期弁開度を設定するため、貯湯槽５の湯水混合層領域の湯も沸き上げることができ、そのため、外気温度が変化しても常に貯湯槽５の湯容積を有効に利用できるので、湯切れの可能性も少くすることができる。
【００６９】
（実施例１０）
図２２は本発明の実施例１０のヒートポンプ給湯機の構成図、図２３は同ヒートポンプ給湯機の外気温度に対する目標吐出温度を示す説明図である。
【００７０】
本実施例において、実施例１と異なる点は、外気温度を検出する外気温度検出手段１６からの信号に応じて、目標吐出温度を決定する制御手段１１を設けた構成としていることである。なお、実施例１と同符号の部分は同一構成を有し、説明は省略する。
【００７１】
次に動作、作用について説明する。一般に、外気温度が高くなると、蒸発器４が大気熱から得るエネルギーは大きくなる。それに従って、冷媒循環量が増加するので、圧縮機１の吐出温度と吐出圧力とを上限吐出温度および上限吐出圧力以下にするためには、減圧装置３の弁開度を大きく（開く）する必要がある。そこで、予め、実施例１で示した図２の関係を外気温度を変えて求める。そして、その外気温度に対して目標吐出温度Ｙを求めると図２３のようになる。すなわち、図２３は横軸に外気温度をとり、縦軸に目標吐出温度をとって、外気温度に対する目標吐出温度の変化を示したものである。
【００７２】
そこで、この外気温度に対する目標吐出温度の変化を予め求めておいて、目標吐出温度記憶手段１２に記憶させておく。給湯運転の起動時に、制御手段１１は外気温度検出手段１６からの信号と目標吐出温度記憶手段１２からの信号とによって、目標吐出温度を求める。さらに、制御手段１１は吐出温度検出手段１３からの信号で吐出温度を検出する。そして、今の吐出温度が目標吐出温度よりも高ければ、制御手段１１は減圧装置３の開度を大きくする（開く）ように制御する。逆に、今の吐出温度が目標吐出温度よりも低ければ、制御手段１１は減圧装置３の開度を小さくする（閉じる）ように制御する。
【００７３】
上記のように、目標吐出温度になるように減圧装置３の弁開度を制御するため、外気温度が変化しても常に冷媒回路に適正な冷媒が循環するので、異常温度上昇や異常圧力上昇がなく、耐久性が高く、運転効率も良くすることができる。
【００７４】
（実施例１１）
図２４は本発明の実施例１１のヒートポンプ給湯機の構成図、図２５は同ヒートポンプ給湯機の給水温度に対する目標吐出温度と吐出圧力とを示す説明図である。
【００７５】
本実施例において、実施例１と異なる点は、冷媒対水熱交換器２の水側入口水温である給水温度を検出する給水温度検出手段８からの信号に応じて、目標吐出温度を決定する制御手段１１を設けた構成としていることである。なお、実施例１と同符号の部分は同一構成を有し、説明は省略する。
【００７６】
次に動作、作用について説明する。実施例８の図１６で説明したように、貯湯槽５内の高温湯と低温水の接する部分で高温湯と低温水が混合した混合層が生じる。そして、この混合槽内の水が冷媒対水熱交換器２に送られるが、この冷媒対水熱交換器２に送られる水の温度（給水温度）は時間とともに高くなる。図２５は横軸に給水温度をとり、縦軸に目標吐出温度と吐出圧力とをとって、給水温度に対する目標吐出温度と吐出圧力の変化を示したものである。同図中、一点鎖線は、目標吐出温度を一定（目標吐出温度Ｔｇ１）とした場合である。そしてこの場合は、給水温度の上昇とともに、吐出圧力も上昇し、時には、上限吐出圧力を越える場合もある。
【００７７】
そこで、冷媒対水熱交換器２の水側入口水温である給水温度がＴｗｘの時に、目標吐出温度Ｔｇ１を、この目標吐出温度Ｔｇ１より低い目標吐出温度Ｔｇ２（Ｔｇ１＞Ｔｇ２）に変更する。さらに、制御手段１１は吐出温度検出手段１３からの信号で吐出温度を検出する。この場合、今の吐出温度は目標吐出温度よりも高いので、制御手段１１は減圧装置３の開度を大きくする（開く）ように制御する。その結果、図２５の実線に示すように、吐出圧力はＰ１からＰ２（Ｐ１＞Ｐ２）に減少しする。
【００７８】
上記のように、貯湯槽５における混合層から冷媒対水熱交換器２に送られた給水温度が高くなった時に目標吐出温度を低く設定し、さらに、この低く設定した目標吐出温度になるように減圧装置３の弁開度を制御するため、給水温度が変化しても常に冷媒回路に適正な冷媒が循環するので、異常温度上昇や異常圧力上昇がなく、耐久性が高く、運転効率を良くするこことができる。
【００７９】
（実施例１２）
図２６は本発明の実施例１２のヒートポンプ給湯機の構成図、図２７は同ヒートポンプ給湯機の沸き上げ温度に対する目標吐出温度を示す説明図である。
【００８０】
本実施例において、実施例１と異なる点は、冷媒対水熱交換器２の水側出口水温である沸き上げ温度の到達目標温度である目標沸き上げ温度を記憶している目標沸き上げ温度記憶手段１９に応じて、目標吐出温度を決定する制御手段１１を設けた構成としていることである。なお、実施例１と同符号の部分は同一構成を有し、説明は省略する。
【００８１】
次に動作、作用について説明する。一般に、沸き上げ温度を高くするには、冷媒対水熱交換器２を循環する冷媒の温度を高くする必要がある。そこで、予め、実施例１で示した図２の関係を沸き上げ温度を変えて求める。そして、その沸き上げ温度に対して目標吐出温度Ｙを求めると図２７のようになる。すなわち、図２７は横軸に沸き上げ温度をとり、縦軸に目標吐出温度をとって、沸き上げ温度に対する目標吐出温度の関係を示したものである。
【００８２】
そこで、この沸き上げ温度に対する目標吐出温度の関係を予め求めておいて、目標吐出温度記憶手段１２に記憶させておく。給湯運転の起動時に、制御手段１１は目標沸き上げ温度記憶手段１９からの信号と目標吐出温度記憶手段１２からの信号とによって、目標吐出温度を求める。さらに、制御手段１１は吐出温度検出手段１３からの信号で吐出温度を検出する。そして、吐出温度が目標吐出温度になるように減圧装置３の弁開度を制御する。
【００８３】
図２７に示す沸き上げ温度に対する目標吐出温度の関係の代わりに、次のように簡略化した関係で目標吐出温度を求めてもほぼ同様の効果が得られる。すなわち、目標吐出温度を目標沸き上げ温度よりも所定の温度ΔＴだけ高く設定する。動作、作用は上述と同様なので説明は省略する。
【００８４】
なお、上記各実施例においては冷媒を特に記載していないが、このような装置に使用する冷媒であればどのようなものであっても良く、例えばＨＣＦＣ（Ｒ２２）冷媒、ＨＦＣ冷媒（Ｒ４１０Ａ）冷媒、ＣＯ2冷媒、プロパン冷媒等が考えられる。
【００８５】
上記のように、目標吐出温度になるように減圧装置３の弁開度を制御するため、沸き上げ温度を変更しても常に冷媒回路に適正な冷媒が循環するので、異常温度上昇や異常圧力上昇がなく、耐久性が高く、運転効率も良くすることができる。
【００８６】
【発明の効果】
以上のように、本発明によれば、目標吐出温度になるように減圧装置の弁開度を制御するため、常に冷媒回路に適正な冷媒が循環するので、運転効率を良くすることができる。
【図面の簡単な説明】
【図１】
本発明の実施例１のヒートポンプ給湯機を示す構成図
【図２】
同ヒートポンプ給湯機の減圧装置の開度に対する吐出温度と吐出圧力と効率を示す説明図
【図３】
本発明の実施例２のヒートポンプ給湯機の構成図
【図４】
同ヒートポンプ給湯機の運転時間に対する吐出温度を示す説明図
【図５】
本発明の実施例３のヒートポンプ給湯機の構成図
【図６】
同ヒートポンプ給湯機の運転時間に対する吐出温度を示す説明図
【図７】
本発明の実施例４のヒートポンプ給湯機の構成図
【図８】
同ヒートポンプ給湯機の運転停止後の圧縮機の温度に対する吐出温度検出手段を付けている配管の温度を示す説明図
【図９】
本発明の実施例５のヒートポンプ給湯機の構成図
【図１０】
本発明の実施例６のヒートポンプ給湯機の構成図
【図１１】
同ヒートポンプ給湯機の運転停止後の時間に対する吐出温度検出手段を付けている配管の温度を示す説明図
【図１２】
同ヒートポンプ給湯機の外気温度に対する熱時冷時判定時間を示す説明図
【図１３】
本発明の実施例７のヒートポンプ給湯機の構成図
【図１４】
同ヒートポンプ給湯機の外気温度に対する減圧装置の弁開度と冷媒循環量とを示す説明図
【図１５】
本発明の実施例８のヒートポンプ給湯機の構成図
【図１６】
同ヒートポンプ給湯機の貯湯槽の高さ方向に対する貯湯槽内の湯の温度を示す説明図
【図１７】
同ヒートポンプ給湯機の給水温度に対する吐出圧力を示す説明図
【図１８】
同ヒートポンプ給湯機の給水温度に対する減圧装置の弁開度を示す説明図
【図１９】
本発明の実施例９のヒートポンプ給湯機の構成図
【図２０】
同ヒートポンプ給湯機の給水温度に対する吐出圧力を示す説明図
【図２１】
同ヒートポンプ給湯機の給水温度に対する減圧装置の弁開度を示す説明図
【図２２】
本発明の実施例１０のヒートポンプ給湯機の構成図
【図２３】
同ヒートポンプ給湯機の外気温度に対する目標吐出温度を示す説明図
【図２４】
本発明の実施例１１のヒートポンプ給湯機の構成図
【図２５】
同ヒートポンプ給湯機の給水温度に対する目標吐出温度と吐出圧力とを示す説明図
【図２６】
本発明の実施例１２のヒートポンプ給湯機の構成図
【図２７】
同ヒートポンプ給湯機の沸き上げ温度に対する目標吐出温度を示す説明図
【図２８】
従来例におけるヒートポンプ給湯機の構成図
【符号の説明】
１ 圧縮機
２ 冷媒対水熱交換器
３ 減圧装置
４ 蒸発器
５ 貯湯槽
６ 循環ポンプ
８ 給水温度検出手段
１１ 制御手段
１３ 吐出温度検出手段
１６ 外気温度検出手段
１７ 圧縮機温度検出手段
１８ 時間計測手段 [Document name] statement
Patent application title: Heat pump water heater
[Claim of claim]
  1. A compressor, a refrigerant-to-water heat exchanger, a pressure reducing device for controlling the flow rate of a refrigerant, and an evaporatorProvidedA refrigerant circulation circuit, a hot water storage tank, a circulation pump, and the refrigerant-to-water heat exchanger;ProvidedHot water supply circuit and discharge temperature detection means for detecting discharge temperature of the compressorAnd the discharge temperature of the compressor is set to improve the efficiency of the hot water supply operation.The valve opening degree of the pressure reducing device is controlled to achieve the target discharge temperature.RuiPump water heater.
  [Claim 2] A compressor, a refrigerant-to-water heat exchanger, a pressure reducing device for controlling the flow rate of the refrigerant, a refrigerant circulation circuit provided with an evaporator, a hot water storage tank, a circulation pump, a hot water supply circuit provided with the refrigerant-to-water heat exchanger, A discharge temperature detection means for detecting a discharge temperature of the compressor, and controlling the opening degree of the pressure reducing device such that the discharge temperature of the compressor becomes a target discharge temperature at which the efficiency of the hot water supply operation approaches the maximumPump water heater.
  [Claim3A compressor opening degree of the pressure reducing device is set to a preset initial valve opening degree at startup of the compressor.Or 2Heat pump water heater as described.
  [Claim4A thermal cold detection means for determining a thermal start when the compressor is warm and a cold start when the compressor is cold when the compressor starts, and a cold start and a thermal start Setting the initial valve opening accordingly3Heat pump water heater as described.
  [Claim5A hot-cold detection means is a discharge temperature detection means for detecting the discharge temperature of the compressor and an outside air temperature detection means for detecting the outside air temperature.4Heat pump water heater as described.
  [Claim6A hot-cold detection means is a compressor temperature detection means for detecting the temperature on the high pressure side of the compressor.4Heat pump water heater as described.
  [Claim7A thermal time cold detection means is a time measurement means for measuring an elapsed time from the previous operation stop and an outside air temperature detection means for detecting an outside air temperature.4Heat pump water heater as described.
  [Claim8An initial valve opening degree is set according to a signal from outside air temperature detecting means for detecting outside air temperature.3Heat pump water heater as described.
  [Claim9An initial valve opening degree is set according to a signal from a feed water temperature detecting means for detecting a feed water temperature which is a water side inlet water temperature of a refrigerant-to-water heat exchanger.3Heat pump water heater as described.
  [Claim10An initial valve opening degree is set according to a signal from a feed water temperature detecting means for detecting a feed water temperature which is a water side inlet water temperature of a refrigerant-to-water heat exchanger and a signal from an outside air temperature detecting means for detecting an outside air temperature. Claim to do3Heat pump water heater as described.
  [Claim11A target discharge temperature is set according to a signal from outside air temperature detecting means for detecting outside air temperature.Or 2Heat pump water heater as described.
  [Claim12A control means is provided for determining a target discharge temperature according to a signal from a feed water temperature detection means for detecting a feed water temperature which is a water side inlet water temperature of a refrigerant-to-water heat exchanger.Or 2Heat pump water heater as described.
  [Claim13A control means for determining a target discharge temperature in accordance with a target boiling temperature which is an ultimate target temperature of a boiling temperature which is a water side outlet water temperature of a refrigerant-to-water heat exchanger is characterized.Or 2Heat pump water heater as described.
  14. The heat pump water heater according to any one of claims 1 to 13, wherein the refrigerant is carbon dioxide.
Detailed Description of the Invention
      [0001]
  Field of the Invention
  The present invention relates to a hot water storage type heat pump water heater.
      [0002]
  [Prior Art]
  A conventional heat pump water heater of this type is disclosed in Japanese Patent Application Laid-Open No. 60-164157. FIG. 28 is a block diagram of a conventional heat pump water heater. In FIG. 28, a refrigerant circulation circuit comprising a compressor 1, a refrigerant-to-water heat exchanger 2, a pressure reducing device 3 and an evaporator 4, a hot water storage tank 5, a circulation pump 6, the refrigerant-to-water heat exchanger 2, a supplementary heater A high temperature and high pressure superheated gas refrigerant discharged from the compressor 1 flows into the refrigerant-to-water heat exchanger 2, where it heats the water sent from the circulation pump 6 . Then, the refrigerant heat-exchanged with this water is decompressed by the pressure reducing device 3 and flows into the evaporator 4, where it absorbs the heat of the atmosphere to be evaporated and gasified, and returns to the compressor 1. On the other hand, the hot water heated by the refrigerant-to-water heat exchanger 2 flows into the upper portion of the hot water storage tank 5 and is gradually stored from above. Then, when the inlet water temperature of the refrigerant-to-water heat exchanger 2 reaches the set value, the feed water temperature detection means 8 detects it, stops the heat pump operation by the compressor 1, and switches to the sole operation of the auxiliary heater 7. It is a thing.
      [0003]
  [Problems to be solved by the invention]
  In the heat pump water heater of the conventional example shown in FIG. 28, a capillary tube or a thermal expansion valve is used as the pressure reducing device 3. When a capillary tube is used as the decompression device 3, generally, the specifications of the capillary tube are designed based on the temperature conditions of summer when the amount of refrigerant circulation is large. Therefore, since the refrigerant flows more than necessary at the start of operation especially in winter except summer, the temperature rise of the compressor 1 is slow, and the hot water at the outlet of the refrigerant-to-water heat exchanger 2 flows into the upper part of the hot water tank 5 with low temperature. It is stored hot water. Therefore, it mixes with the hot water in the hot water storage tank 5, and the hot water temperature of the hot water storage tank 5 is made to fall, and there existed a subject that a hot water shortage might occur. In addition, even during steady operation after the temperature of the compressor 1 has risen, more refrigerant than necessary is circulated in the refrigerant circuit, so that the operation efficiency is degraded. Furthermore, in some cases, the liquid refrigerant is sucked into the compressor 1, and as a result, there is also a problem that the liquid is compressed to deteriorate the durability of the compressor 1.
      [0004]
  On the other hand, when a thermal expansion valve is used as the decompression device 3, generally, the thermal expansion valve as the decompression device 3 is set so that the refrigerant at the outlet of the evaporator 4 is in the superheated gas state with a certain degree of superheat. Design the specifications of However, since the distribution of the refrigerant in the refrigerant circuit is not stable at the start of operation, the discharge pressure or discharge temperature of the compressor 1 may be hunting (vertical fluctuation) and exceed the upper limit discharge pressure or upper limit discharge temperature. The problem was that the durability of the In addition, even during steady operation, when the temperature is higher than the designed outside air temperature, the discharge pressure rises, or in winter when the outside air temperature is low, the discharge temperature rises, and the durability of the compressor becomes worse. Was.
      [0005]
  The object of the present invention is to reduce the number of hot water, EffectiveIt is about realizing a hot water supply heating operation with a good rate.
      [0006]
  [Means for Solving the Problems]
  In order to solve the above-mentioned conventional problems, a heat pump water heater according to the present invention includes a compressor, a refrigerant-to-water heat exchanger, a pressure reducing device for controlling the flow rate of refrigerant, and an evaporator.ProvidedA refrigerant circulation circuit, a hot water storage tank, a circulation pump, and the refrigerant-to-water heat exchanger;ProvidedHot water supply circuit and discharge temperature detection means for detecting discharge temperature of the compressorAnd the discharge temperature of the compressor is set to improve the efficiency of the hot water supply operation.The valve opening degree of the pressure reducing device is controlled to achieve the target discharge temperature.RumoIt is
      [0007]
  By this, in order to control the valve opening degree of the pressure reducing device so as to reach the target discharge temperature, the proper refrigerant is always circulated in the refrigerant circuit, and both the pressure and the temperature are stabilized.
      [0008]
  BEST MODE FOR CARRYING OUT THE INVENTION
  The present invention can be practiced in the form described in each claim, and the invention described in claim 1 includes a compressor, a refrigerant-to-water heat exchanger, a pressure reducing device for controlling the flow rate of the refrigerant, and an evaporator.ProvidedA refrigerant circulation circuit, a hot water storage tank, a circulation pump, and the refrigerant-to-water heat exchanger;ProvidedHot water supply circuit and discharge temperature detection means for detecting discharge temperature of the compressorAnd the discharge temperature of the compressor is set to improve the efficiency of the hot water supply operation.The valve opening degree of the pressure reducing device is controlled to achieve the target discharge temperature.According to the present invention, the compressor, the refrigerant-to-water heat exchanger, the pressure reducing device for controlling the flow rate of the refrigerant, the refrigerant circulation circuit provided with the evaporator, the hot water tank, the circulation pump A hot water supply circuit provided with the refrigerant-to-water heat exchanger, and a discharge temperature detection means for detecting a discharge temperature of the compressor, the discharge temperature of the compressor being a target at which the efficiency of the hot water supply operation is near maximum The opening degree of the pressure reducing device is controlled to reach the discharge temperatureBecause the proper refrigerant always circulates in the refrigerant circuit, Driving efficiencyYou can do better.
      [0009]
  Claim3The invention described herein includes control means for setting the valve opening degree of the pressure reducing device to a preset initial valve opening degree at the time of starting the compressor, so that a refrigerant appropriate for the refrigerant circuit can be obtained also at the start of operation. Is circulated, so there is no abnormal temperature rise or pressure rise due to hunting of the discharge temperature or discharge pressure of the compressor and durability is high, and the temperature rise of the compressor is fast, and the refrigerant-to-water heat exchanger outlet immediately Because the hot water becomes hot, the possibility of running out of water can be reduced.
      [0010]
  Claim4The invention described herein includes a thermal cold detection means for determining a thermal start when the compressor is warm and a cold start when the compressor is cold when the compressor starts, and a cold start In order to set the valve opening degree of the pressure reducing device according to the initial temperature of the compressor by providing control means for determining the initial valve opening degree according to the heat start-up, the refrigerant circuit also at the operation start Because the proper refrigerant circulates, the temperature of the compressor rises rapidly even when it is particularly cold, and the hot water at the outlet of the refrigerant-to-water heat exchanger quickly becomes hot, so the possibility of hot water leakage can be reduced. .
      [0011]
  Claim5The invention described herein is provided with discharge temperature detection means for detecting the discharge temperature of the compressor and outside air temperature detection means for detecting the outside air temperature as heat-time cold detection means, even if the outside air temperature changes. In order to set the valve opening degree of the pressure reducing device according to the initial temperature of the compressor with respect to the outside air temperature, an appropriate refrigerant circulates in the refrigerant circuit also at the start of operation. The temperature rise of the water rapidly increases, and the hot water at the outlet of the refrigerant to the water heat exchanger immediately becomes hot, so the possibility of water loss can be reduced.
      [0012]
  Claim6In order to directly detect the temperature of the compressor as described above, the invention of the present invention comprises the compressor temperature detection means for detecting the temperature on the high pressure side of the compressor as the hot / cold detection means. Since there is no waiting time for hot hour cold determination and the valve opening degree of the pressure reducing device can be set to the optimum value simultaneously with the operation start, the operating efficiency can be improved.
      [0013]
  Claim7The invention of the present application includes, as the hot cold detection means, a time measuring means for measuring an elapsed time from the previous operation stop and an outside air temperature detection means for detecting the outside air temperature. Since heat and cold are judged from the time and the outside air temperature, the judgment can be made at the same time as the operation start, and the operation efficiency can always be improved even if the outside air temperature changes.
      [0014]
  Claim8According to the present invention, the control device for determining the initial valve opening degree according to the signal from the outside air temperature detection means for detecting the outside air temperature controls the initial valve opening degree of the pressure reducing device with respect to the outside air temperature. In order to set, even when the outside air temperature changes, the proper refrigerant circulates at the start of operation, so there is no abnormal temperature rise or abnormal pressure rise due to hunting of discharge temperature or discharge pressure of the compressor, and durability is high. Since the temperature rise of the compressor is fast and the hot water at the outlet of the refrigerant to the water heat exchanger immediately becomes hot, the possibility of the hot water leakage can be reduced.
      [0015]
  Claim9According to the invention, the storage of hot water by providing a control means for determining an initial valve opening degree according to a signal from a feed water temperature detection means for detecting a feed water temperature which is a water side inlet water temperature of the refrigerant to water heat exchanger. The hot water in the hot and cold water mixing layer area of the tank can also be boiled, so that the hot water volume of the hot water storage tank can be effectively used, so the possibility of running out of hot water can be reduced.
      [0016]
  Claim10According to the invention, the signal from the feed water temperature detecting means for detecting the feed water temperature which is the water side inlet water temperature of the refrigerant-to-water heat exchanger and the signal from the outside air temperature detecting means for detecting the outside air temperature By providing control means for determining the initial valve opening degree, the hot water of the hot water / water mixing layer area of the hot water storage tank can also be boiled up, so that the hot water volume of the hot water storage tank is always effective even if the outside air temperature changes. Because it can be used, the possibility of running out of water can be reduced.
      [0017]
  Claim11According to the present invention, the control device for determining the target discharge temperature is provided according to the signal from the outside air temperature detection means for detecting the outside air temperature, so that the valve opening degree of the pressure reducing device is adjusted to the target discharge temperature. In order to control, even when the outside air temperature changes, the proper refrigerant is always circulated in the refrigerant circuit, so there is no abnormal temperature rise and abnormal pressure rise, and the durability is high, and the operating efficiency can be improved.
      [0018]
  Claim12According to the invention, the feed water is provided by comprising control means for determining a target discharge temperature in accordance with a signal from the feed water temperature detection means for detecting the feed water temperature which is the water side inlet water temperature of the refrigerant to water heat exchanger. In order to set the target discharge temperature low when the temperature rises and to control the valve opening of the pressure reducing device so that the target discharge temperature set low is achieved, the refrigerant circuit is always used even if the water supply temperature changes. Since a proper refrigerant circulates, there is no abnormal temperature rise and abnormal pressure rise, the durability is high, and the operating efficiency can be improved.
      [0019]
  Claim13According to the invention, the target discharge is achieved by providing control means for determining the target discharge temperature in accordance with the target boiling temperature which is the target temperature to be reached of the boiling temperature which is the water side outlet water temperature of the refrigerant to water heat exchanger. In order to control the valve opening degree of the pressure reducing device so as to reach the temperature, the proper refrigerant is always circulated in the refrigerant circuit even if the target boiling temperature is changed, so there is no abnormal temperature rise and abnormal pressure rise, and durability The driving efficiency can also be improved.The invention according to claim 14 is characterized in that the refrigerant is carbon dioxide.
      [0020]
  【Example】
  Hereinafter, embodiments of the present invention will be described with reference to the drawings.
      [0021]
  Example 1
  FIG. 1 is a block diagram of a heat pump water heater according to a first embodiment of the present invention, and FIG. 2 is an explanatory view showing a discharge temperature, a discharge pressure and an efficiency with respect to an opening degree of a pressure reducing device of the heat pump water heater. The same reference numerals are used for the same components as in FIG. 28 described in the conventional example, and the description is omitted.
      [0022]
  In FIG. 1, the rotational speed control means 10 controls the rotational speed of the circulation pump 6 by the signal from the boiling temperature detection means 9 provided at the water side outlet of the refrigerant to water heat exchanger 2, and the refrigerant to water heat is The outlet water temperature (boiling temperature) of the exchanger 2 is boiled to be substantially constant. Further, the control means 11 controls the pressure reducing device 3 by the signals from the target discharge temperature storage means 12 storing the target discharge temperature and the discharge temperature detection means 13 detecting the discharge temperature of the compressor 1. There is an electric expansion valve (not shown) or the like as the pressure reducing device 3.
      [0023]
  Next, the operation and action will be described. In FIG. 2, the abscissa represents the valve opening degree of the pressure reducing device 3, and the ordinate axis represents the discharge temperature and the discharge pressure, and the discharge temperature and the discharge pressure with respect to the valve opening degree of the pressure reducing device 3 at a certain outside temperature. It shows the relationship of efficiency. As can be seen from the figure, the efficiency has a maximum value with respect to the valve opening degree of the pressure reducing device 3. Further, in the figure, the alternate long and short dash line indicates the upper limit discharge temperature (normal maximum discharge temperature) during normal use of the compressor, and the two dotted line indicates the upper limit discharge pressure (normal maximum discharge pressure) during normal use of the compressor. .
      [0024]
  Here, the discharge temperature with respect to the valve opening degree X of the pressure reducing device 3 at which the efficiency is maximized is set as the target discharge temperature Y. The target discharge temperature Y is stored in advance in the target discharge temperature storage means 12.
      [0025]
  That is, when the hot water supply operation starts and the compressor 1 is started, the control means 11 detects the discharge temperature by the signal from the discharge temperature detection means 13. Then, with the information from the target discharge temperature storage means 12 storing the target discharge temperature, if the current discharge temperature is higher than the target discharge temperature, the control means 11 increases the valve opening degree of the pressure reducing device 3 (open ) To control. On the contrary, if the current discharge temperature is lower than the target discharge temperature, the control means 11 performs control to reduce (close) the valve opening degree of the pressure reducing device 3.
      [0026]
  As described above, if the discharge temperature control by the control means 11 is performed at certain intervals, efficient hot water supply operation can always be performed. Further, since the proper refrigerant is always circulated in the refrigerant circuit in order to control the valve opening degree of the pressure reducing device 3 so as to reach the target discharge temperature, there is no abnormal temperature rise or abnormal pressure rise, and the durability is also improved. it can.
      [0027]
  (Example 2)
  FIG. 3 is a block diagram of the heat pump water heater according to the second embodiment of the present invention, and FIG. 4 is an explanatory view showing the discharge temperature with respect to the operation time of the heat pump water heater.
      [0028]
  The present embodiment differs from the first embodiment in that an initial valve opening degree storage means 14 is provided which stores the valve opening degree of the pressure reducing device 3 at the time of operation start. In addition, the part of the same code as Example 1 has the same structure, and description is abbreviate | omitted.
      [0029]
  Next, the operation and action will be described. In FIG. 3, at the time of operation start, the control means 11 controls the valve of the pressure reducing device 3 by the signal from the initial valve opening degree storing means 14 storing the valve opening degree (initial valve opening degree) of the pressure reducing device 3 at the time of starting. After the opening degree is set to the initial valve opening degree, the hot water supply heating operation is started.
      [0030]
  FIG. 4 shows the operation temperature on the horizontal axis and the discharge temperature on the vertical axis, and shows the discharge temperature change with respect to the operation time. In the figure, Tg is a target discharge temperature. Further, Td0 is the control start discharge temperature, and the valve opening degree of the pressure reducing device 3 is made constant at the initial valve opening degree until the discharge temperature reaches this temperature, and if the discharge temperature becomes this control start discharge temperature Td0 or more, As described in Example 1, the discharge temperature control operation is performed. That is, the control means 11 detects the discharge temperature by the signal from the discharge temperature detection means 13. Then, with the information from the target discharge temperature storage means 12 storing the target discharge temperature, if the current discharge temperature is higher than the target discharge temperature, the control means 11 increases the valve opening degree of the pressure reducing device 3 (open ) To control. On the contrary, if the current discharge temperature is lower than the target discharge temperature, the control means 11 performs control to reduce (close) the valve opening degree of the pressure reducing device 3.
      [0031]
  Now, in FIG. 4, the discharge temperature reaches the target discharge temperature, and the valve opening degree of the pressure reducing device 3 when the steady state is reached is referred to as the reaching valve opening degree. In the same figure, the solid line A shows the change of the discharge temperature when the valve opening degree of the pressure reducing device 3 is operated at the reaching valve opening degree after the operation start. If the valve is operated at a valve opening smaller (closed) than the ultimate valve opening, it will be as shown by the alternate long and short dash line B, the discharge temperature will be hunting (vertical fluctuation), and in some cases the upper limit discharge temperature will be exceeded There is also. Conversely, when operating at a valve opening degree larger (open) than the ultimate valve opening degree, it becomes as shown by a dotted line C, and the discharge temperature rises slowly, and it takes time to reach the target discharge temperature.
      [0032]
  Therefore, the valve opening degree Z, which is the ultimate valve opening degree, is obtained in advance and stored in the initial valve opening degree storage means 14. At the start of the hot water supply operation, the control means 11 obtains an initial valve opening degree (valve opening degree Z) of the pressure reducing device 3 in accordance with a signal from the initial valve opening degree storage means 14. Then, after setting the valve opening degree of the pressure reducing device 3 to the valve opening degree Z, the control means 11 starts the hot water supply heating operation.
      [0033]
  As described above, by setting the valve opening degree of the pressure reducing device 3 to the preset initial valve opening degree at the start of operation, the appropriate refrigerant circulates in the refrigerant circuit, so the discharge temperature and discharge of the compressor 1 There is no abnormal temperature rise and pressure rise due to pressure hunting, and the durability is high, and the discharge temperature rise of the compressor 1 is fast, and the hot water at the outlet of the refrigerant-to-water heat exchanger 2 quickly becomes hot. There is also the possibility of
      [0034]
  (Example 3)
  FIG. 5 is a block diagram of the heat pump water heater according to the third embodiment of the present invention, and FIG. 6 is an explanatory view showing the discharge temperature with respect to the operation time of the heat pump water heater.
      [0035]
  The present embodiment is different from the second embodiment in that a configuration is provided with thermal cold detection means 15 for detecting thermal start when the compressor 1 is warm and cold start when the compressor 1 is cold. It is that you are. Here, the discharge temperature detection means 13 is used as the hot cold detection means 15. In addition, the part of the same code as Example 2 has the same structure, and description is abbreviate | omitted.
      [0036]
  Next, the operation and action will be described. In FIG. 6, the abscissa represents the operation time, and the ordinate represents the discharge temperature, and shows the change of the discharge temperature with respect to the operation time. In the figure, Tg is a target discharge temperature. Further, Td0 is the control start discharge temperature, and the valve opening degree of the pressure reducing device 3 is made constant at the initial valve opening degree until the discharge temperature reaches this temperature, and if the discharge temperature becomes this control start discharge temperature Td0 or more, As described in Example 1, the discharge temperature control operation is performed. The change of the discharge temperature shown by the solid line in the figure is the case of thermal start-up when the compressor 1 is warm at the time of operation start, and the change of the discharge temperature shown by the alternate long and short dash line is that the compressor 1 is cold at the time of operation start It is the case of cold start. As can be seen from the figure, in the case of thermal start-up, the rise is fast and the steady state is immediately reached. On the other hand, in the case of cold start, the rise is slow, and it takes time to reach a steady state. The valve opening degree (the valve opening degree Z described in the second embodiment) of the pressure reducing device 3 when the steady state is reached is the same in both the heat activation and the cold activation. In order to speed up the start of the cold start, in the case of the cold start, the initial valve opening degree of the pressure reducing device 3 is set smaller than in the case of the heat start. Then, as shown by the dotted line (improved when cold) in the same figure, the rise of the discharge temperature becomes relatively fast.
      [0037]
  In FIG. 6, Tjd is defined as the hot cold judgment discharge temperature for determining the distinction between hot start and cold start, and after the operation start and after a predetermined waiting time t, the hot start and cold start are distinguished. It shall judge. That is, at the start of the hot water supply operation, the control means 11 obtains the initial valve opening degree (valve opening degree Z) of the pressure reducing device 3 based on the signal from the initial valve opening degree storage means 14. Then, after setting the valve opening degree of the pressure reducing device 3 to the valve opening degree Z, the control means 11 starts the hot water supply heating operation. Then, if the discharge temperature obtained from the signal from the discharge temperature detection means 13 is a temperature at the hot cold judgment discharge temperature Tjd or more (point A) after a predetermined standby time t after activation, the heat start judgment is made. If the temperature (point B) is lower than the hot cold determination discharge temperature Tjd, the cold start is determined. As a result of the determination, in the case of heat activation, the operation is continued with the valve opening degree (valve opening degree Z) as it is. On the other hand, in the case of cold start, the control means 11 sets the valve opening degree of the pressure reducing device 3 to a valve opening degree (valve opening degree Zm) smaller than the valve opening degree Z and continues the operation. The valve opening degree Zm is determined in advance in the range where there is no large overshoot of the discharge temperature. When the discharge temperature becomes equal to or higher than the control start discharge temperature Td0 in both the heat start and the cold start, the discharge temperature control operation is performed as described in the first embodiment. That is, the control means 11 detects the discharge temperature by the signal from the discharge temperature detection means 13. Then, with the information from the target discharge temperature storage means 12 storing the target discharge temperature, if the current discharge temperature is higher than the target discharge temperature, the control means 11 increases the valve opening degree of the pressure reducing device 3 (open ) To control. On the contrary, if the current discharge temperature is lower than the target discharge temperature, the control means 11 performs control to reduce (close) the valve opening degree of the pressure reducing device 3.
      [0038]
  As described above, in order to set the valve opening degree of the pressure reducing device 3 according to the temperature at startup of the compressor 1, the proper refrigerant circulates in the refrigerant circuit also at startup, so that the compressor is particularly cold The temperature rise of 1 is quick, and the hot water at the outlet of the refrigerant-to-water heat exchanger 2 quickly becomes hot, so the possibility of the hot water leakage can be reduced.
      [0039]
  (Example 4)
  FIG. 7 is a block diagram of a heat pump water heater according to a fourth embodiment of the present invention, and FIG. 8 is an explanatory view showing the temperature of the pipe to which the discharge temperature detecting means is attached with respect to the temperature of the compressor after the operation of the heat pump water heater is stopped. is there.
      [0040]
  The present embodiment differs from the third embodiment in that the discharge temperature detection unit 13 and the outside air temperature detection unit 16 are used as the hot-cold detection unit 15. In addition, the part of the same code as Example 3 has the same structure, and description is abbreviate | omitted.
      [0041]
  Next, the operation and action will be described. In FIG. 8, the abscissa represents the temperature of the compressor 1 after the operation is stopped, and the ordinate represents the temperature of the pipe to which the discharge temperature detecting means 13 is attached, and the discharge temperature detection with respect to the temperature of the compressor 1 after the operation is stopped. The relationship of the temperature change of piping which has attached the means 13 is shown. Now, the discharge temperature detection means 13 for detecting the discharge temperature is provided in a pipe connected to the discharge port of the compressor 1. Since the refrigerant circulates during operation, the temperature of the compressor 1 and the temperature of the piping portion attached with the discharge temperature detection means 13 are almost equal, but when the operation is stopped, the temperature of the compressor 1 and the discharge temperature detection The temperature is different from the temperature of the piping unit to which the means 13 is attached. That is, the heat capacity of the compressor 1 is larger than that of the pipe attached to the discharge temperature detection means 13, and the compressor 1 is usually covered with a heat insulating material for soundproofing. For this reason, the speed of temperature reduction of the compressor 1 is smaller than the speed of temperature reduction of the pipe attached to the discharge temperature detection means 13. In addition, the rate of temperature decrease also depends on the outside air temperature. Naturally, the lower the outside air temperature, the faster the temperature drops.
      [0042]
  In the figure, Tg is the target discharge temperature, and Tj is the temperature of the hot cold determination compressor which determines the distinction between hot start and cold start. That is, when the temperature of the compressor 1 is Tj or more at the start of operation, it is a heat start, and when it is smaller than Tj, it is a cold start. The solid line shows the relationship between the temperature of the compressor 1 after the operation is stopped in summer (for example, the outside air temperature of 35 ° C.) and the temperature of the pipe to which the discharge temperature detection means 13 is attached. Similarly, the alternate long and short dash line and the dotted line indicate the relationship in the middle period (for example, the outside air temperature 20 ° C.) and in the winter (for example, the outside air temperature 5 ° C.). In the above-mentioned relationship in summer, middle period, and winter, the temperature of the pipe attached with the discharge temperature detection means 13 when the temperature of the compressor 1 after operation stoppage becomes the hot cold determination compressor temperature Tj is T1 respectively , T2 and T3. Then, if T1, T2 and T3 are obtained in advance with respect to the outside air temperature (for example, 35 ° C., 20 ° C. and 5 ° C.), heat start-up or cooling is performed by the signal from the discharge temperature detection means 13 You can judge when it is activated.
      [0043]
  As described above, even if the outside air temperature changes, the degree of valve opening of the pressure reducing device 3 corresponding to the initial temperature of the compressor 1 is set with respect to the outside air temperature. The temperature of the compressor rises rapidly even when it is cold, and the hot water at the outlet of the refrigerant-to-water heat exchanger quickly becomes hot, so that the possibility of hot water can be reduced.
      [0044]
  (Example 5)
  FIG. 9 is a block diagram of a heat pump water heater according to a fifth embodiment of the present invention. The present embodiment differs from the third embodiment in that a compressor temperature detection unit 17 is used as the hot-cold detection unit 15. In addition, the part of the same code as Example 3 has the same structure, and description is abbreviate | omitted.
      [0045]
  Next, the operation and action will be described. As described in the fourth embodiment, assuming that the temperature of the compressor 1 that determines the distinction between the hot start and the cold start is the hot cold determination compressor temperature Tj, the temperature of the compressor 1 at the start of operation is If the temperature is equal to or greater than Tj, it is a heat activation, and if smaller than Tj, it is a cold activation.
      [0046]
  That is, at the start of the hot water supply operation, the control means 11 obtains the temperature of the compressor 1 by the signal from the compressor temperature detection means 17. Then, if the obtained temperature is equal to or higher than the above-mentioned hot cold determination compressor temperature Tj, the control means 11 determines that the hot start is performed and sets the valve opening degree of the pressure reducing device 3 to the valve opening degree Z. After that, the hot water supply heating operation is started. Conversely, if the temperature determined above is lower than the above-described hot hour cold determination compressor temperature Tj, the control means 11 determines cold start and the valve open degree of the pressure reducing device 3 is smaller than the valve open degree Z After the valve opening degree Zm is set, the hot water supply heating operation is started.
      [0047]
  As described above, since the temperature of the compressor 1 is directly detected, there is no waiting time for hot cold determination, and the valve opening degree of the pressure reducing device 3 can be set to an optimal value simultaneously with operation start. Can be improved.
      [0048]
  (Example 6)
  FIG. 10 is a block diagram of a heat pump water heater according to a sixth embodiment of the present invention, FIG. 11 is an explanatory view showing the temperature of the pipe to which the discharge temperature detecting means 13 is attached with respect to the time after the operation of the heat pump water heater is stopped, These are explanatory drawings which show the heat | fever cold determination time with respect to the external temperature of the heat pump water heater.
      [0049]
  The present embodiment differs from the third embodiment in that the hot cold detection means 15 uses a time measuring means 18 for measuring the elapsed time from the previous operation stop and an outside air temperature detection means 16 for detecting the outside air temperature. It is to have a configuration. In addition, the part of the same code as Example 3 has the same structure, and description is abbreviate | omitted.
      [0050]
  Next, the operation and action will be described. In FIG. 11, the abscissa represents the time after the operation is stopped, and the ordinate represents the temperature of the pipe to which the discharge temperature detection means 13 is attached, and the pipe to which the discharge temperature detection means 13 is attached with respect to the time after the operation stop It shows the relationship of temperature change. In the figure, Tg is a target discharge temperature, and Tjh is a heat-temperature-cold determination discharge piping temperature for determining the distinction between heat-activation and cold-activation. Now, the discharge temperature detection means 13 for detecting the discharge temperature is provided in a pipe connected to the discharge port of the compressor 1. When the operation is stopped, the temperature of the compressor 1 decreases, and the temperature of the pipe to which the discharge temperature detection means 13 is attached also decreases. In addition, the rate of temperature decrease also depends on the outside air temperature. Naturally, the lower the outside air temperature, the faster the temperature drops. In the figure, the solid line shows the change of the temperature of the pipe to which the discharge temperature detecting means 13 is attached with respect to the time after the operation is stopped in summer (for example, the outside air temperature 35 ° C.). Similarly, the alternate long and short dash line and the dotted line respectively indicate the change in temperature of the pipe to which the discharge temperature detection means 13 is attached in the middle period (for example, outside temperature 20 ° C.) and in winter (for example, outside temperature 5 ° C.). Also, if the temperature of the pipe to which the discharge temperature detection means 13 is attached is the heat cold determination judgment pipe temperature Tjh for determining the distinction between heat start and cold start, it is heat start, it is heat start If it is less than the cold determination discharge pipe temperature Tjh, it is cold start. The time after operation shutdown when the temperature of the piping to which the discharge temperature detection means 13 is attached in summer, middle period, and winter becomes equal to the hot cold determination discharge piping temperature Tjh is t1, t2, and t3, respectively. This time is taken as the heat cold judgment time. That is, when starting operation, if the time from the previous operation stop is less than this hot cold judgment time, it is hot start, and if it is larger than this hot cold judgment time, cold boot and Become.
      [0051]
  In FIG. 12, the abscissa represents the outside air temperature, and the ordinate represents the hot cold determination time. The relationship between the hot cold determination time and the outside air temperature is shown. In the figure, the part shown by the solid line is the heat activation, and the upper part is the cold activation. By obtaining the relationship of FIG. 12 in advance, it is possible to determine whether the heat activation or the cold activation is performed by the signal from the time measuring unit 18 and the outside air temperature detecting unit 16.
      [0052]
  That is, at the start of the hot water supply operation, the control means 11 obtains the elapsed time from the previous operation stop by the signal from the time measuring means 18 and further obtains the outside air temperature by the signal from the outside air temperature detection means 16. Then, if the elapsed time from the previous operation stop is equal to or less than the above hot cold determination time at the calculated outside air temperature, the control means 11 determines that it is hot start, and the valve opening degree of the pressure reducing device 3 After the valve opening degree Z is set, the hot water supply heating operation is started. On the contrary, if the elapsed time from the previous operation stop is longer than the above-mentioned hot cold determination time, the control means 11 determines that it is cold start, and the valve opening degree of the pressure reducing device 3 is smaller than the valve opening degree Z After the degree (valve opening degree Zm) is set, the hot water supply heating operation is started.
      [0053]
  As described above, since heat and cold are judged from the elapsed time from the previous operation stop and the outside air temperature, judgment can be made at the same time as the operation start, and operation efficiency is always improved even if the outside air temperature changes. be able to.
      [0054]
  (Example 7)
  FIG. 13 is a block diagram of a heat pump water heater according to a seventh embodiment of the present invention, and FIG. 14 is an explanatory view showing the valve opening degree of the pressure reducing device with respect to the outside air temperature of the heat pump water heater.
      [0055]
  The present embodiment differs from the second embodiment in that a control means 11 for determining the initial valve opening degree of the pressure reducing device 3 in accordance with a signal from the outside air temperature detection means 16 is provided. In addition, the part of the same code as Example 2 has the same structure, and description is abbreviate | omitted.
      [0056]
  Next, the operation and action will be described. In FIG. 14, the abscissa represents the outside air temperature, and the ordinate represents the refrigerant circulation amount and the valve opening degree of the pressure reducing device 3, showing changes in the refrigerant circulation amount and the valve opening degree of the pressure reducing device 3 with respect to the outside air temperature. It is. Generally, when the outside air temperature rises, the energy the evaporator 4 obtains from atmospheric heat increases. Accordingly, as shown in the figure, the refrigerant circulation amount increases, so that the discharge temperature and the discharge pressure of the compressor 1 become equal to or lower than the upper limit discharge temperature and the upper limit discharge pressure. Need to be large (open).
      [0057]
  Therefore, the valve opening degree Z, which is the ultimate valve opening degree described in the second embodiment, is obtained in advance with respect to the outside air temperature, and stored in the initial valve opening degree storage unit 14. At the start of the hot water supply operation, the control means 11 obtains the initial valve opening degree (valve opening degree Z) of the pressure reducing device 3 from the signal from the outside air temperature detection means 16 and the signal from the initial valve opening degree storage means 14. Then, after setting the valve opening degree of the pressure reducing device 3 to the valve opening degree Z, the control means 11 starts the hot water supply heating operation.
      [0058]
  As described above, since the initial degree of valve opening of the pressure reducing device 3 is set with respect to the outside air temperature, the appropriate refrigerant circulates at the start of operation even if the outside air temperature changes. There is no abnormal temperature rise and pressure rise due to pressure hunting, and the durability is high, and the temperature rise of the compressor 1 is fast, and the hot water at the outlet of the refrigerant-to-water heat exchanger 2 quickly becomes hot. The possibility can also be reduced.
      [0059]
  (Example 8)
  FIG. 15 is a block diagram of a heat pump water heater according to an eighth embodiment of the present invention, FIG. 16 is an explanatory view showing the temperature of hot water in the hot water storage tank with respect to the height direction of the hot water tank of the heat pump water heater, FIG. FIG. 18 is an explanatory drawing showing the valve opening degree of the pressure reducing device with respect to the water supply temperature of the heat pump water heater of the same.
      [0060]
  The present embodiment differs from the second embodiment in that the initial valve opening degree is determined according to the signal from the feed water temperature detection means 8 for detecting the feed water temperature which is the water side inlet water temperature of the refrigerant to water heat exchanger 2. The control means 11 is provided. In addition, the part of the same code as Example 2 has the same structure, and description is abbreviate | omitted.
      [0061]
  Next, the operation and action will be described. FIG. 16 shows the temperature of the hot water in the hot water storage tank 5 on the horizontal axis, and the height of the hot water storage tank 5 on the vertical axis to show the temperature distribution of the hot water in the hot water storage tank. As described above, the rotational speed control means 10 controls the rotational speed of the circulation pump 6 by the signal from the boiling temperature detection means 9 provided at the water side outlet of the refrigerant to water heat exchanger 2, and the refrigerant to water The outlet water temperature (boiling temperature) of the heat exchanger 2 is boiled to be substantially constant. However, with the passage of the boiling operation time, a mixed layer in which the high temperature water and the low temperature water are mixed is formed in the portion where the high temperature water and the low temperature water in the hot water storage tank 5 are in contact. In the figure, the above-mentioned mixed layer is generated by heat conduction and convection of high temperature water and low temperature water, and the heat is transferred from the high temperature water to the low temperature water, and the temperature of the high temperature water decreases at the boundary. Low temperature water rises in temperature. Therefore, near the completion of the boiling operation, the temperature of the water flowing into the refrigerant-to-water heat exchanger 2 rapidly rises with time. In FIG. 17, the abscissa represents the feed water temperature which is the water-side inlet water temperature of the refrigerant to water heat exchanger 2, the ordinate represents the discharge pressure, and the valve opening degree of the pressure reducing device 3 is a parameter. Shows the relationship of As can be seen from the figure, the higher the feed water temperature, the higher the discharge pressure, but for the same feed water temperature, the larger the valve opening of the pressure reducing device 3, the lower the discharge pressure. Now, assuming that the design discharge pressure is Ps, the feed water temperatures at which the design discharge pressure Ps is reached are Tw1, Tw2 and Tw3, respectively, for large, medium and small valve openings of the pressure reducing device 3. Further, FIG. 18 shows this relationship with respect to the water supply temperature and the valve opening degree of the pressure reducing device 3. That is, the horizontal axis is the feedwater temperature which is the water-side inlet water temperature of the refrigerant to water heat exchanger 2, and the vertical axis is the valve opening degree of the pressure reducing device 3, and the relation of the valve opening degree of the pressure reducing device 3 to the water supply temperature Is shown.
      [0062]
  Therefore, the valve opening degree Z, which is the ultimate valve opening degree described in the second embodiment, is obtained in advance with respect to the water supply temperature, and stored in the initial valve opening degree storage unit 14. At the start of the hot water supply operation, the control means 11 obtains the initial valve opening degree (valve opening degree Z) of the pressure reducing device 3 from the signal from the feed water temperature detection means 8 and the signal from the initial valve opening degree storage means 14. Then, after setting the valve opening degree of the pressure reducing device 3 to the valve opening degree Z, the control means 11 starts the hot water supply heating operation.
      [0063]
  As described above, since the initial valve opening degree is set according to the water supply temperature, the hot water in the hot and cold water mixing layer area of the hot water storage tank 5 can be boiled, and therefore, the hot water volume of the hot water storage tank 5 can be effectively used. The possibility of running out of water can also be reduced.
      [0064]
  (Example 9)
  FIG. 19 is a block diagram of a heat pump water heater according to a ninth embodiment of the present invention, FIG. 20 is an explanatory view showing the discharge pressure with respect to the water supply temperature of the heat pump water heater, and FIG. 21 is a valve of the pressure reducing device with respect to the water supply temperature of the heat pump water heater It is an explanatory view showing an opening.
      [0065]
  The present embodiment differs from the second embodiment in the outside air temperature detection means for detecting the signal from the water supply temperature detection means 8 for detecting the water supply temperature which is the water side inlet water temperature of the refrigerant to water heat exchanger 2 and the outside air temperature. According to the signal from 16, the control means 11 which determines an initial stage valve-opening degree is provided. In addition, the part of the same code as Example 2 has the same structure, and description is abbreviate | omitted.
      [0066]
  Next, the operation and action will be described. In FIG. 20, the horizontal axis is the feed water temperature, which is the water-side inlet water temperature of the refrigerant to water heat exchanger 2, and the vertical axis is the discharge pressure, so that the outside air temperature (eg, summer 35 ° C., mid-term 20 ° C., winter The relationship between the discharge pressure and the feed water temperature when the valve opening degree of the pressure reducing device 3 is constant with 5 ° C. as a parameter is shown. As can be seen from the figure, the larger the energy (summer> intermediate> winter) that the evaporator 4 obtains from atmospheric heat, the higher the discharge pressure. Now, in FIG. 20, for each outside air temperature (summer, middle period, winter), what is described in FIG. 17 holds. Furthermore, if the relationship between the water supply temperature and the valve opening degree of the pressure reducing device 3 described in FIG. 18 is obtained for each outside air temperature (summer, middle period, winter), it is as shown in FIG. That is, in FIG. 21, the horizontal axis is the feed water temperature which is the water-side inlet water temperature of the refrigerant to water heat exchanger 2, and the vertical axis is the valve opening degree of the pressure reducing device 3. The relationship between the feed water temperature and the valve opening degree of the pressure reducing device 3 is shown with the intermediate period 20 ° C. and winter 5 ° C. as parameters.
      [0067]
  Therefore, the valve opening degree Z, which is the ultimate valve opening degree described in the second embodiment, is previously obtained with respect to the water supply temperature using the outside air temperature as a parameter, and stored in the initial valve opening degree storage unit 14. At the start of the hot water supply operation, the control means 11 receives the signal from the feed water temperature detection means 8, the signal from the outside air temperature detection means 16 and the signal from the initial valve opening degree storage means 14 Find the opening degree Z). Then, after setting the valve opening degree of the pressure reducing device 3 to the valve opening degree Z, the control means 11 starts the hot water supply heating operation.
      [0068]
  As described above, since the initial valve opening degree is set according to the water supply temperature and the outside air temperature, the hot water of the hot and cold water mixing layer area of the hot water storage tank 5 can also be boiled up, so even if the outside air temperature changes. Since the hot water volume of the hot water storage tank 5 can be used effectively at all times, the possibility of running out of water can also be reduced.
      [0069]
  (Example 10)
  22 is a block diagram of a heat pump water heater of Embodiment 10 of the present invention, and FIG. 23 is an explanatory view showing a target discharge temperature with respect to the outside air temperature of the heat pump water heater.
      [0070]
  The present embodiment differs from the first embodiment in that a control means 11 for determining a target discharge temperature is provided in accordance with a signal from an outside air temperature detection means 16 for detecting an outside air temperature. In addition, the part of the same code as Example 1 has the same structure, and description is abbreviate | omitted.
      [0071]
  Next, the operation and action will be described. Generally, when the outside air temperature rises, the energy the evaporator 4 obtains from atmospheric heat increases. Accordingly, the amount of refrigerant circulation increases, so to make the discharge temperature and discharge pressure of the compressor 1 equal to or lower than the upper limit discharge temperature and the upper limit discharge pressure, it is necessary to increase (open) the valve opening degree of the pressure reducing device 3 There is. Therefore, the relationship of FIG. 2 shown in the first embodiment is obtained in advance by changing the outside air temperature. Then, when the target discharge temperature Y is obtained with respect to the outside air temperature, it becomes as shown in FIG. That is, FIG. 23 shows the change of the target discharge temperature with respect to the outside air temperature with the outside air temperature taken along the horizontal axis and the target discharge temperature taken along the vertical axis.
      [0072]
  Therefore, the change of the target discharge temperature with respect to the outside air temperature is obtained in advance, and stored in the target discharge temperature storage means 12. At the start of the hot water supply operation, the control means 11 obtains a target discharge temperature from the signal from the outside air temperature detection means 16 and the signal from the target discharge temperature storage means 12. Further, the control means 11 detects the discharge temperature by the signal from the discharge temperature detection means 13. Then, if the current discharge temperature is higher than the target discharge temperature, the control means 11 controls the pressure reducing device 3 to increase (open) the opening degree. Conversely, if the current discharge temperature is lower than the target discharge temperature, the control means 11 controls the pressure reducing device 3 to reduce (close) the opening degree.
      [0073]
  As described above, since the valve opening degree of the pressure reducing device 3 is controlled to reach the target discharge temperature, the appropriate refrigerant is always circulated in the refrigerant circuit even if the outside air temperature changes, so the abnormal temperature rise or abnormal pressure rise The durability is high and the driving efficiency can be improved.
      [0074]
  (Example 11)
  FIG. 24 is a block diagram of a heat pump water heater of Embodiment 11 of the present invention, and FIG. 25 is an explanatory view showing a target discharge temperature and a discharge pressure with respect to a water supply temperature of the heat pump water heater.
      [0075]
  The present embodiment differs from the first embodiment in that the target discharge temperature is determined according to the signal from the feed water temperature detection means 8 that detects the feed water temperature which is the water side inlet water temperature of the refrigerant to water heat exchanger 2. The configuration is such that the control means 11 is provided. In addition, the part of the same code as Example 1 has the same structure, and description is abbreviate | omitted.
      [0076]
  Next, the operation and action will be described. As described with reference to FIG. 16 of the eighth embodiment, a mixed layer in which the high temperature water and the low temperature water are mixed is formed in the portion of the hot water storage tank 5 in contact with the high temperature water and the low temperature water. Then, the water in the mixing tank is sent to the refrigerant-to-water heat exchanger 2, and the temperature (feed water temperature) of the water sent to the refrigerant-to-water heat exchanger 2 increases with time. In FIG. 25, the abscissa represents the feed water temperature, and the ordinate represents the target discharge temperature and the discharge pressure, and shows changes in the target discharge temperature and the discharge pressure with respect to the water supply temperature. In the figure, the dashed-dotted line is the case where the target discharge temperature is constant (target discharge temperature Tg1). In this case, as the feed water temperature rises, the discharge pressure also rises, and sometimes the upper limit discharge pressure is exceeded.
      [0077]
  Therefore, when the feed water temperature, which is the water-side inlet water temperature of the refrigerant-to-water heat exchanger 2, is Twx, the target discharge temperature Tg1 is changed to a target discharge temperature Tg2 (Tg1> Tg2) lower than the target discharge temperature Tg1. Further, the control means 11 detects the discharge temperature by the signal from the discharge temperature detection means 13. In this case, since the present discharge temperature is higher than the target discharge temperature, the control means 11 controls the pressure reducing device 3 to increase (open) the opening degree. As a result, the discharge pressure decreases from P1 to P2 (P1> P2) as shown by the solid line in FIG.
      [0078]
  As described above, when the temperature of the water supplied from the mixed layer in the hot water storage tank 5 to the refrigerant-to-water heat exchanger 2 becomes high, the target discharge temperature is set low, and this set low target discharge temperature In order to control the valve opening degree of the pressure reducing device 3, the proper refrigerant is always circulated in the refrigerant circuit even if the feed water temperature changes, so there is no abnormal temperature rise and abnormal pressure rise, and the durability is high and the operating efficiency is high. You can do better.
      [0079]
  (Example 12)
  FIG. 26 is a block diagram of a heat pump water heater of Embodiment 12 of the present invention, and FIG. 27 is an explanatory view showing a target discharge temperature with respect to a boiling temperature of the heat pump water heater.
      [0080]
  The present embodiment differs from the first embodiment in the target boiling temperature memory which stores a target boiling temperature which is an ultimate target temperature of the boiling temperature which is the water side outlet water temperature of the refrigerant to water heat exchanger 2. According to the means 19, the control means 11 for determining the target discharge temperature is provided. In addition, the part of the same code as Example 1 has the same structure, and description is abbreviate | omitted.
      [0081]
  Next, the operation and action will be described. Generally, in order to increase the boiling temperature, it is necessary to increase the temperature of the refrigerant circulating in the refrigerant-to-water heat exchanger 2. Therefore, the relationship of FIG. 2 shown in the first embodiment is obtained in advance by changing the boiling temperature. Then, when the target discharge temperature Y is obtained with respect to the boiling temperature, it is as shown in FIG. That is, FIG. 27 shows the relationship between the boiling temperature and the target discharge temperature with the boiling temperature taken on the horizontal axis and the target discharge temperature taken on the vertical axis.
      [0082]
  Therefore, the relationship between the target discharge temperature and the boiling temperature is obtained in advance, and stored in the target discharge temperature storage means 12. At the start of the hot water supply operation, the control means 11 obtains a target discharge temperature from the signal from the target heating temperature storage means 19 and the signal from the target discharge temperature storage means 12. Further, the control means 11 detects the discharge temperature by the signal from the discharge temperature detection means 13. Then, the valve opening degree of the pressure reducing device 3 is controlled so that the discharge temperature becomes the target discharge temperature.
      [0083]
  Instead of the relationship between the target discharge temperature and the boiling temperature shown in FIG. 27, almost the same effect can be obtained even if the target discharge temperature is determined by the following simplified relationship. That is, the target discharge temperature is set higher than the target boiling temperature by a predetermined temperature ΔT. The operation and action are the same as described above, and therefore the description is omitted.
      [0084]
  Although the refrigerant is not particularly described in the above embodiments, any refrigerant may be used as long as it is used in such an apparatus, for example, HCFC (R22) refrigerant, HFC refrigerant (R410A) A refrigerant, a CO2 refrigerant, a propane refrigerant, etc. can be considered.
      [0085]
  As described above, in order to control the valve opening degree of the pressure reducing device 3 so as to reach the target discharge temperature, the appropriate refrigerant is always circulated in the refrigerant circuit even if the boiling temperature is changed. There is no rise, the durability is high, and the driving efficiency can be improved.
      [0086]
  【Effect of the invention】
  As above,BookAccording to the invention, since the valve opening degree of the pressure reducing device is controlled to reach the target discharge temperature, the proper refrigerant is always circulated in the refrigerant circuit., Driving efficiencyYou can do better.
Brief Description of the Drawings
  [Fig. 1]
  The block diagram which shows the heat pump water heater of Example 1 of this invention.
  [Fig. 2]
  Explanatory drawing which shows discharge temperature, discharge pressure, and efficiency with respect to the opening degree of the decompression device of the heat pump water heater
  [Fig. 3]
  The block diagram of the heat pump water heater of Example 2 of this invention
  [Fig. 4]
  Explanatory drawing which shows the discharge temperature with respect to the operating time of the heat pump water heater
  [Fig. 5]
  The block diagram of the heat pump water heater of Example 3 of this invention
  [Fig. 6]
  Explanatory drawing which shows the discharge temperature with respect to the operating time of the heat pump water heater
  [Fig. 7]
  The block diagram of the heat pump water heater of Example 4 of this invention
  [Fig. 8]
  Explanatory drawing which shows the temperature of piping which attached the discharge temperature detection means with respect to the temperature of the compressor after the shutdown of the heat pump water heater.
  [Fig. 9]
  The block diagram of the heat pump water heater of Example 5 of this invention
  [Fig. 10]
  The block diagram of the heat pump water heater of Example 6 of this invention
  [Fig. 11]
  Explanatory drawing which shows the temperature of piping which attached the discharge temperature detection means with respect to the time after the shutdown of the heat pump water heater of the same.
  [Fig. 12]
  Explanatory drawing which shows the heat | fever cold time determination time with respect to the external temperature of the heat pump water heater
  [Fig. 13]
  The block diagram of the heat pump water heater of Example 7 of this invention
  [Fig. 14]
  Explanatory drawing which shows the valve opening degree of a pressure-reduction apparatus with respect to the external temperature of the heat pump water heater, and a refrigerant | coolant circulation amount
  [Fig. 15]
  The block diagram of the heat pump water heater of Example 8 of this invention
  [Fig. 16]
  Explanatory drawing which shows the temperature of the hot water in a storage tank with respect to the height direction of the storage tank of the heat pump water heater
  [Fig. 17]
  Explanatory drawing which shows the discharge pressure with respect to the water supply temperature of the heat pump water heater
  [Fig. 18]
  Explanatory drawing which shows the valve-opening degree of the decompression device with respect to the water supply temperature of the heat pump water heater
  [Fig. 19]
  The block diagram of the heat pump water heater of Example 9 of this invention
  [Fig. 20]
  Explanatory drawing which shows the discharge pressure with respect to the water supply temperature of the heat pump water heater
  [Fig. 21]
  Explanatory drawing which shows the valve-opening degree of the decompression device with respect to the water supply temperature of the heat pump water heater
  [Fig. 22]
  The block diagram of the heat pump water heater of Example 10 of this invention
  [Fig. 23]
  An explanatory view showing the target discharge temperature to the open air temperature of the heat pump water heater
  [Fig. 24]
  The block diagram of the heat pump water heater of Example 11 of this invention
  [Fig. 25]
  Explanatory drawing which shows the target discharge temperature with respect to the feed water temperature of the heat pump water heater, and discharge pressure.
  [FIG. 26]
  The block diagram of the heat pump water heater of Example 12 of this invention
  [Fig. 27]
  Explanatory drawing which shows the target discharge temperature with respect to the boiling temperature of the heat pump water heater
  [Fig. 28]
  Diagram of heat pump water heater in prior art
  [Description of the code]
  1 Compressor
  2 Refrigerant to water heat exchanger
  3 Pressure reducing device
  4 evaporator
  5 hot water storage tank
  6 Circulating pump
  8 Water supply temperature detection means
  11 Control means
  13 Discharge temperature detection means
  16 Outside temperature detection means
  17 Compressor temperature detection means
  18-hour measuring means