JP3719161B2

JP3719161B2 - Heat pump water heater

Info

Publication number: JP3719161B2
Application number: JP2001149073A
Authority: JP
Inventors: 昌宏尾浜; 竹司渡辺; 松本　　聡
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2001-05-18
Filing date: 2001-05-18
Publication date: 2005-11-24
Anticipated expiration: 2021-05-18
Also published as: JP2002340401A

Description

【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１３は従来のヒートポンプ給湯機の構成図である。図１３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、凝縮液化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】
しかしながら、上記のような従来例の構成では、沸き上げ運転時間の経過とともに貯湯槽５内の湯と水の接する部分で湯水混合層が生じ、その層は次第に拡大していく。図１４は貯湯槽５内の湯の温度分布を示す。同図中において、Ｔ１は沸き上げ温度（高温湯）であり、Ｔ２は市水温度（低温湯）である。前述の湯水混合層は、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、貯湯槽５の沸き上げ完了近くになると、冷媒対水熱交換器２に流入する給水温度は高くなるため、圧縮機１の吐出圧力は上昇して、モータの巻線温度の上昇など圧縮機１の耐久性が課題となってくる。
【０００４】
図１５は横軸に冷媒対水熱交換器２に流入する給水温度をとり、縦軸にその時の圧縮機１の吐出圧力をとって、給水温度に対する圧縮機１の吐出圧力の関係を示したグラフである。同図中の圧力Ｐは常用上限圧力であり、圧縮機１の耐久性を保証するためには、通常運転ではこの圧力以下で運転する必要がある。圧力Ｐの時の給水温度は同図中よりＴ３となる。また、有効な湯温の下限をＴｕ（例えば４５℃）とし、このＴ３とＴｕを図１４に示す。同図の左側に示す貯湯槽５の断面図において、湯温Ｔ３以下の領域は沸き上げ可能な領域であり、Ｔｕ以上の領域は有効な湯として使用できる領域である。しかし、湯温Ｔ３とＴｕの間の領域（斜線の部分）は有効な湯として利用できない領域である。
【０００５】
このように従来例の構成では、冷媒対水熱交換器２に流れる水温が低い状態で運転を停
止せざるをえないので、貯湯槽５の下部が低温の水の状態で停止することになり、貯湯槽５の湯容量を有効に利用できない。そのため、貯湯熱量は減少し、給湯負荷を満足することができない。これを解決する方法の一つとして、貯湯槽５の容量を大きくすることが考えられる。しかし、この場合には、貯湯槽５の設置面積が大きくなり、設置の自由度が制限され、かつ、コストが高くなるという課題がある。また、他の方法として、ヒートポンプ運転を停止した後、補助加熱器７の単独運転で貯湯熱量を増加する方法がある。しかし、この場合には、ヒータなどで加熱するため、消費電力が大きくなり、効率が悪くなるという課題がある。
【０００６】
本発明は、上記従来の課題を解決するもので、圧縮機の異常温度上昇ならびに異常圧力上昇もなく、低消費電力量で貯湯槽の下部まで高温湯を貯湯し、湯容量を有効に利用可能としたヒートポンプ給湯機の提供を目的とする。
【０００７】
【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、貯湯槽の沸き上げを行う給湯加熱運転中において、給水温度検出手段が沸き上げ完了直前解除温度を検出した時点より以前に沸き上げ完了直前解除温度よりも高温である沸き上げ完了直前検出温度を検出して減圧装置の弁開度を大きくしていれば、給水温度検出手段が沸き上げ完了直前解除温度を検出した時に減圧装置の弁開度を小さくするように制御する制御手段を備えたものである。
【０００８】
これにより、沸き上げ完了に近づき、圧縮機の吐出圧力が上昇する場合に減圧装置の弁開度を開くように制御し、吐出圧力を低く押さえるので、高温の給水温度まで給湯加熱運転が可能となり、さらに、その後、出湯等で給水温度が低くなった場合には、減圧装置の弁開度を閉じるように制御するので、効率の良い給湯加熱運転が可能となるものである。
【０００９】
【発明の実施の形態】
請求項１に記載の発明は、能力可変の圧縮機、冷媒対水熱交換器、減圧装置を接続した冷媒循環回路と、貯湯槽下部に蓄えられる水を冷媒対水熱交換器へ供給した後に貯湯槽上部へ流入させる給湯回路と、冷媒対水熱交換器の水側出口水温を所定値にするために給湯回路の流量を制御する流量調整弁と、冷媒対水熱交換器の水側入口において貯湯槽下部から給水される水の給水温度を検出する給水温度検出手段と、貯湯槽の沸き上げを行う給湯加熱運転中において、給水温度検出手段が沸き上げ完了直前解除温度を検出した時点より以前に沸き上げ完了直前解除温度よりも高温である沸き上げ完了直前検出温度を検出して減圧装置の弁開度を大きくしていれば、給水温度検出手段が沸き上げ完了直前解除温度を検出した時に減圧装置の弁開度を小さくするように制御する制御手段とを備えたことにより、沸き上げ完了に近づき、圧縮機の吐出圧力が上昇する場合に、減圧装置の弁開度を変更し、吐出圧力を低く押さえ、高温の給水温度まで給湯加熱運転が可能となり、有効な湯として利用できない無駄な領域がより少なくなるため、貯湯槽の湯容量を有効に利用できるものであり、さらに、その後、出湯等で給水温度が低くなった場合には、減圧装置の開度を閉じるように制御するので、効率の良い給湯加熱運転が可能となるものである。
【００１０】
請求項２に記載の発明は、能力可変の圧縮機、冷媒対水熱交換器、減圧装置を接続した冷媒循環回路と、貯湯槽下部に蓄えられる水を冷媒対水熱交換器へ供給した後に貯湯槽上部へ流入させる給湯回路と、冷媒対水熱交換器の水側出口水温を所定値にするために給湯回路の流量を制御する流量調整弁と、圧縮機の吐出圧力を検出する吐出圧力検出手段と、貯湯槽の沸き上げを行う給湯加熱運転中において、吐出圧力検出手段が沸き上げ完了直前解除圧力を検出した時点より以前に沸き上げ完了直前解除圧力よりも高圧である沸き上げ完了直前検出圧力を検出して減圧装置の弁開度を大きくしていれば、吐出圧力検出手段が沸き上げ完了直前解除圧力を検出した時に減圧装置の弁開度を小さくするように制御する制御手段とを備えたことにより、直接吐出圧力を制御して吐出圧力に応じた最適な減圧装置の弁開度の変更を行うので、圧縮機のより確実な耐久性の向上となり、また、効率の良い給湯加熱運転ができるものである。
【００１１】
請求項３に記載の発明は、能力可変の圧縮機、冷媒対水熱交換器、減圧装置を接続した冷媒循環回路と、貯湯槽下部に蓄えられる水を冷媒対水熱交換器へ供給した後に貯湯槽上部へ流入させる給湯回路と、冷媒対水熱交換器の水側出口水温を所定値にするために給湯回路の流量を制御する流量調整弁と、冷媒対水熱交換器の水側入口において貯湯槽下部から給水される水の給水温度を検出する給水温度検出手段と、貯湯槽から出湯したことを検出する出湯検出手段と、貯湯槽の沸き上げを行う給湯加熱運転中において、出湯検出手段による出湯検出時間が所定時間を計測した時点より以前に沸き上げ完了直前検出手段が沸き上がり直前を検出して減圧装置の弁開度を大きくしていれば、出湯検出手段による出湯検出時間が所定時間を計測した時に減圧装置の弁開度を小さくするように制御する制御手段とを備えたことにより、沸き上げ完了直前検出時には減圧装置の弁開度を変更するので、貯湯槽の湯容量を有効に利用でき、かつ、効率の良い給湯加熱運転ができるものであり、その後、出湯したことを検出して沸き上げ完了直前の検知を解除した時には給水温度が下がるため減圧装置の弁開度を変更するので、効率の良い給湯加熱運転が可能となるものである。
【００１２】
請求項４に記載の発明は、出湯検出手段として、貯湯槽から出湯される湯温を検出する出湯温度検出手段を備えたことにより、出湯温度検出手段が出湯温度を検出して出湯を検知した時には、給水温度が下がるため減圧装置の弁開度を閉じるように制御するので、効率の良い給湯加熱運転が可能となるものである。
【００１３】
請求項５に記載の発明は、能力可変の圧縮機、冷媒対水熱交換器、減圧装置を接続した冷媒循環回路と、貯湯槽下部に蓄えられる水を冷媒対水熱交換器へ供給した後に貯湯槽上部へ流入させる給湯回路と、冷媒対水熱交換器の水側出口水温を所定値にするために給湯回路の流量を制御する流量調整弁と、貯湯槽の下部温度を検出する貯湯槽温度検出手段と、貯湯槽の沸き上げを行う給湯加熱運転中において、貯湯槽温度検出手段が沸き上げ完了直前解除温度を検出した時点より以前に沸き上げ完了直前解除温度よりも高温である沸き上げ完了直前検出温度を検出して減圧装置の弁開度を大きくしていれば、貯湯槽温度検出手段が沸き上げ完了直前解除温度を検出した時に減圧装置の弁開度を小さくするように制御する制御手段とを備えたことにより、直接貯湯槽温度の検出を行い、この貯湯槽温度に応じた最適な減圧装置の弁開度の変更を行うので、圧縮機のより確実な耐久性の向上となり、また、効率の良い給湯加熱運転ができるものである。
【００１４】
【実施例】
以下、本発明の実施例について、図面を参照しながら説明する。
【００１５】
（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沸き上げ完了直前解除がない場合の運転時間に対する沸き上げ完了直前検出手段の検出状態と圧縮機の運転状態と減圧装置の弁開度と吐出圧力と給水温度とを示すグラフ、図３は同ヒートポンプ給湯機の貯湯槽の温度分布を示す説明図、図４は同ヒートポンプ給湯機の沸き上げ完了直前解除がある場合の運転時間に対する沸き上げ完了直前検出手段の検出状態と圧縮機の運転状態と減圧装置の弁開度と吐出圧力と給水温度とを示すグラフである。なお、従来例で説明した図１３と同じ構成部材には同一符号を用い説明を省略する。
【００１６】
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からの信号で流量制御手段１０は流量調整弁１１の開度を制御して、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１２は、沸き上げ完了の直前を検出する沸き上げ完了直前検出手段１３からの信号、または、沸き上げ完了の直前を検出したことを解除する沸き上げ完了直前解除手段１４からの信号で、減圧装置３の弁開度を制御するものである。さらに、状態記憶手段１５は、沸き上げ完了直前検出手段１３が沸き上げ完了の直前を検出したか否かを記憶するものであり、１６は給水管である。
【００１７】
なお、沸き上げ完了直前検出手段１３および沸き上げ完了直前解除手段１４として、ここでは、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を用いる。また、流量調整弁１１としてはステッピングモータで駆動する電動バルブ（図示せず）などがあり、さらに、減圧装置３として電動膨張弁（図示せず）などがある。
【００１８】
次に動作、作用について説明する。まず、沸き上げ完了直前解除がない場合について説明する。図２は横軸に運転時間をとり、縦軸に沸き上げ完了直前検出手段１３の検出状態と圧縮機１の運転状態と減圧装置３の弁開度と吐出圧力と給水温度とをとって、運転時間に対する沸き上げ完了直前検出手段１３の検出状態と圧縮機１の運転状態と減圧装置３の弁開度と吐出圧力と給水温度との関係を示したものである。従来例で説明したように、貯湯槽５の沸き上げ完了近くになると、冷媒対水熱交換器２に流入する給水温度は高くなる。つまり、冷媒対水熱交換器２に流入する水が前述した湯水混合層の部分になると、同図に示すように、運転時間とともに給水温度が上昇する。そして、沸き上げ完了直前検出手段１３である給水温度検出手段８が（沸き上げ温度Ｔ１よりも低い温度である）沸き上げ完了直前検出温度Ｔｈを検出すると、制御手段１２は、減圧装置３の弁開度を大きくする（開く）とともに、制御手段１２からの信号で、状態記憶手段１５は、沸き上げ完了直前検出手段１３が沸き上げ完了の直前を検出したことを記憶する。この時、吐出圧力はＰ１からＰ２に減少する。その後、運転時間の経過とともに給水温度が更に上昇し、それに従って吐出圧力が上昇する。そして、給水温度検出手段８が、常用上限圧力Ｐになる給水温度Ｔ３ａを検出すると、圧縮機を停止し、給湯加熱運転を終了する。なお、同図中の太い点線は、減圧装置３の弁開度の制御を行わない従来例の場合である。運転限界の給水温度がＴ３からＴ３ａへと高くなり、運転範囲が大きくなることがわかる。図３は貯湯槽５内の湯の温度分布を示す。同図の左側に示す貯湯槽５の断面図において、湯温Ｔ３ａ以下の領域は沸き上げ可能な領域であり、Ｔｕ以上の領域は有効な湯として使用できる領域である。有効な湯として利用できない領域は図１４で示した従来例の場合には湯温Ｔ３とＴｕの間の領域であったが、本実施例の場合は湯温Ｔ３ａとＴｕの間の領域（斜線の部分）である。つまり、湯温Ｔ３とＴ３ａの間の領域（点線による斜線の部分）が、本実施例によって、有効になった湯の領域である。
【００１９】
次に、沸き上げ完了直前解除がある場合について説明する。図４は、図２と同様に、横軸に運転時間をとり、縦軸に沸き上げ完了直前検出手段１３の検出状態と圧縮機１の運転状態と減圧装置３の弁開度と吐出圧力と給水温度とをとって、運転時間に対する沸き上げ完了直前検出手段１３の検出状態と圧縮機１の運転状態と減圧装置３の弁開度と吐出圧力と給水温度との関係を示したものである。前述の場合と同様、沸き上げ完了直前検出手段１３である給水温度検出手段８が沸き上げ完了直前検出温度Ｔｈを検出すると、制御手段１２は、減圧装置３の弁開度を大きくする（開く）とともに、制御手段１２からの信号で、状態記憶手段１５は、沸き上げ完了直前検出手段１３が沸き上げ完了の直前を検出したことを記憶する。この時、吐出圧力はＰ１からＰ２に減少する。そして、運転時間の経過とともに給水温度が更に上昇し、それに従って吐出圧力が上昇する。その後、運転時間ｔにおいて、貯湯槽５から出湯されるとともに冷たい水が給水管１６から貯湯槽５に流入すると、給水温度検出手段８が検出する給水温度も低下する。そして、ついに給水温度が沸き上げ完了直前解除温度Ｔｒになると、制御手段１２は状態記憶手段１５の内容を検出する。そして、状態記憶手段１５の内容が、沸き上げ完了の直前を検出したことを記憶しておれば、減圧装置３の弁開度を小さくする（閉める）とともに、状態記憶手段１５は、沸き上げ完了直前検出手段１３が沸き上げ完了の直前を検出した記憶を解除する（もし、状態記憶手段１５の内容が、沸き上げ完了の直前を検出したことを記憶していなければ、減圧装置３の弁開度の制御は行わない）。
【００２０】
その後、運転時間の経過とともに給水温度が更に上昇し、沸き上げ完了直前検出手段１３である給水温度検出手段８が、再度、沸き上げ完了直前検出温度Ｔｈを検出すると、制御手段１２は、再び、減圧装置３の弁開度を大きくするとともに、制御手段１２からの信号で、状態記憶手段１５は、沸き上げ完了直前検出手段１３が沸き上げ完了の直前を検出したことを記憶する。その後、運転時間の経過とともに給水温度が更に上昇し、それに従って吐出圧力が上昇する。そして、給水温度検出手段８が、給水温度Ｔ３ａを検出すると、圧縮機を停止し、給湯加熱運転を終了する。
【００２１】
以上のように、本実施例においては、貯湯槽５全体が沸き上がる直前を検出する沸き上げ完了直前検出手段１３と、貯湯槽５全体が沸き上がる直前を検出したことを解除する沸き上げ完了直前解除手段１４と、沸き上げ完了直前検出手段１３からの信号が所定の第一の信号になった時に減圧装置３の弁開度を開き、その後、沸き上げ完了直前解除手段１４からの信号が所定の第二の信号になった時に減圧装置３の弁開度を閉じるように制御する制御手段１２とを備えたことにより、沸き上げ完了に近づき、圧縮機１の吐出圧力が上昇する場合に、減圧装置３の弁開度を開くように制御し、吐出圧力を低く押さえ、高温の給水温度まで給湯加熱運転が可能となり、貯湯槽５の湯容量を有効に利用できるものであり、その後、出湯等で給水温度が低くなった場合には、減圧装置３の弁開度を閉じるように制御するので、効率の良い給湯加熱運転が可能となるものである。
【００２２】
なお、本実施例において、循環ポンプ６を冷媒対水熱交換器２の水側入口と貯湯槽５との間に設け、流量調整弁１１を循環ポンプ６と冷媒対水熱交換器２の水側入口との間に設けたが、流量調整弁１１の位置としては、循環ポンプ６の入口と貯湯槽５との間に設けても、冷媒対水熱交換器２の水側出口と貯湯槽５との間に設けも、図１の実施例と同様の作用、効果が得られる。
【００２３】
また、冷凍サイクルとしては、図１３の従来例で説明したように、冷媒対水熱交換器２を凝縮器として使用する吐出圧力が臨界点より低い通常のヒートポンプサイクルであってもよいし、冷媒対水熱交換器２をガスクーラとして使用する吐出圧力が臨界点より高い超臨界ヒートポンプサイクルであってもよい。
【００２４】
（実施例２）
図５は本発明の実施例２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沸き上げ完了直前検出手段の検出状態と圧縮機の運転状態と減圧装置の弁開度と吐出圧力とを示すグラフである。
【００２５】
本実施例において、実施例１と異なる点は、沸き上げ完了直前検出手段１３および沸き上げ完了直前解除手段１４として、圧縮機１の吐出圧力を検出する吐出圧力検出手段１７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。
【００２６】
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、縦軸に沸き上げ完了直前検出手段１３の検出状態と圧縮機１の運転状態と減圧装置３の弁開度と吐出圧力とをとって、運転時間に対する沸き上げ完了直前検出手段１３の検出状態と圧縮機１の運転状態と減圧装置３の弁開度と吐出圧力との関係を示したものである。実施例１で説明したように、冷媒対水熱交換器２に流入する水が湯水混合層の部分になると、運転時間とともに給水温度が上昇し、それに従って、同図に示すように、吐出圧も上昇する。そして、沸き上げ完了直前検出手段１３である吐出圧力検出手段１７が沸き上げ完了直前検出圧力Ｐｈを検出すると、制御手段１２は、減圧装置３の弁開度を大きくする（開く）とともに、制御手段１２からの信号で、状態記憶手段１５は、沸き上げ完了直前検出手段１３が沸き上げ完了の直前を検出したことを記憶する。この時、吐出圧力は減少する。そして、運転時間の経過とともに給水温度が更に上昇し、それに従って吐出圧力が上昇する。その後、運転時間ｔにおいて、貯湯槽５から出湯されるとともに冷たい水が給水管１６から貯湯槽５に流入すると、吐出圧力検出手段１７が検出する吐出圧力も低下する。そして、ついに吐出圧力が沸き上げ完了直前解除圧力Ｐｒになると、制御手段１２は状態記憶手段１５の内容を検出する。そして、状態記憶手段１５の内容が、沸き上げ完了の直前を検出したことを記憶しておれば、減圧装置３の弁開度を小さくする（閉める）とともに、状態記憶手段１５は、沸き上げ完了直前検出手段１３が沸き上げ完了の直前を検出した記憶を解除する（もし、状態記憶手段１５の内容が、沸き上げ完了の直前を検出したことを記憶していなければ、減圧装置３の弁開度の制御は行わない）。その後、運転時間の経過とともに給水温度が更に上昇することによって吐出圧力も上昇する。そして、沸き上げ完了直前検出手段１３である吐出圧力検出手段１７が、再度、沸き上げ完了直前検出圧力Ｐｈを検出すると、制御手段１２は、再び、減圧装置３の弁開度を大きくするとともに、制御手段１２からの信号で、状態記憶手段１５は、沸き上げ完了直前検出手段１３が沸き上げ完了の直前を検出したことを記憶する。その後、運転時間の経過とともに給水温度が更に上昇し、それに従って吐出圧力も上昇する。そして、吐出圧力検出手段１７が、常用上限圧力Ｐを検出すると、圧縮機を停止し、給湯加熱運転を終了する。
【００２７】
以上のように、本実施例においては、沸き上げ完了直前検出手段および沸き上げ完了直前解除手段として吐出圧力検出手段を備えたことにより、沸き上げ完了に近づき、圧縮機１の吐出圧力が上昇する場合に、減圧装置３の開度を開くように制御し、吐出圧力を低く押さえ、高温の給水温度まで給湯加熱運転が可能となり、貯湯槽５の湯容量を有効に利用できるものである。その後、出湯等で給水温度が低くなった場合には、減圧装置３の開度を閉じるように制御するので、効率の良い給湯加熱運転が可能となるものである。また、直接吐出圧力で制御するので、圧縮機１のより確実な耐久性の向上になるものである。
【００２８】
（実施例３）
図７は本発明の実施例３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時間に対する沸き上げ完了直前検出手段の検出状態と出湯の有無と減圧装置の弁開度と吐出圧力と給水温度とを示すグラフである。
【００２９】
本実施例において、実施例１と異なる点は、沸き上げ完了直前解除手段１４として貯湯槽５から出湯したことを検出する出湯検出手段１８と前記出湯検出手段１８が出湯したことを検出している時間を計測するタイマー１９とを設けた構成としていることである。また、前記出湯検出手段１８として、ここでは、出湯した湯の流れの有無を検出する流れ検出手段２０を用いる。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。
【００３０】
次に動作、作用について説明する。図８は、横軸に運転時間をとり、縦軸に沸き上げ完了直前検出手段１３の検出状態と出湯の有無と減圧装置３の弁開度と吐出圧力と給水温度とをとって、運転時間に対する沸き上げ完了直前検出手段１３の検出状態と出湯の有無と減圧装置３の弁開度と吐出圧力と給水温度との関係を示したものである。貯湯槽５の沸き上げ完了近くになると、実施例１で説明したように、運転時間とともに給水温度が上昇し、それに従って、同図に示すように、吐出圧力も上昇する。そして、沸き上げ完了直前検出手段１３である給水温度検出手段８が沸き上げ完了直前検出温度Ｔｈを検出すると、制御手段１２は、減圧装置３の弁開度を大きくする（開く）とともに、制御手段１２からの信号で、状態記憶手段１５は、沸き上げ完了直前検出手段１３が沸き上げ完了の直前を検出したことを記憶する。この時、吐出圧力は減少する。そして、運転時間の経過とともに給水温度が更に上昇し、それに従って吐出圧力が上昇する。その後、運転時間ｔにおいて、貯湯槽５から出湯されると、出湯検出手段１８である流れ検出手段２０が出湯した湯の流れを検出し、タイマー１９は出湯している時間を計測する。このタイマー１９の計測した時間が所定の出湯時間ｔｏになると、制御手段１２は状態記憶手段１５の内容を検出する。そして、状態記憶手段１５の内容が、沸き上げ完了の直前を検出したことを記憶しておれば、減圧装置３の弁開度を小さくする（閉める）とともに、状態記憶手段１５は、沸き上げ完了直前検出手段１３が沸き上げ完了の直前を検出したという記憶を解除する（もし、状態記憶手段１５の内容が、沸き上げ完了の直前を検出したことを記憶していなければ、減圧装置３の弁開度の制御は行わない）。
【００３１】
以上のように、本実施例においては、沸き上げ完了直前検出手段として給水温度検出手段８を備え、沸き上げ完了直前解除手段として流れ検出手段２０とタイマー１９とを備えたことにより、沸き上げ完了に近づき、圧縮機１の吐出圧力が上昇する場合に、減圧装置３の弁開度を開くように制御し、吐出圧力を低く押さえ、高温の給水温度まで給湯加熱運転が可能となり、貯湯槽５の湯容量を有効に利用できるものである。その後、所定の時間の出湯を検出した場合には、減圧装置３の弁開度を閉じるように制御するので、効率の良い給湯加熱運転が可能となるものである。また、直接出湯の流れの有無を検出して制御するので、より確実性のある運転が可能である。
【００３２】
（実施例４）
図９は本発明の実施例４のヒートポンプ給湯機の構成図、図１０は同ヒートポンプ給湯機の運転時間に対する沸き上げ完了直前検出手段の検出状態と出湯温度と減圧装置の弁開度と吐出圧力と給水温度とを示すグラフである。本実施例において、実施例３と異なる点は、出湯検出手段１８として貯湯槽５から出湯した湯の温度を検出する出湯温度検出手段２１を設け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。
【００３３】
次に動作、作用について説明する。図１０は、横軸に運転時間をとり、縦軸に沸き上げ完了直前検出手段１３の検出状態と出湯温度と減圧装置３の弁開度と吐出圧力と給水温度とをとって、運転時間に対する沸き上げ完了直前検出手段１３の検出状態と出湯温度と減圧装置３の弁開度と吐出圧力と給水温度との関係を示したものである。実施例３で説明したように、冷媒対水熱交換器２に流入する水が湯水混合層の部分になると、運転時間とともに給水温度が上昇し、それに従って、同図に示すように、吐出圧力も上昇する。そして、沸き上げ完了直前検出手段１３である給水温度検出手段８が沸き上げ完了直前検出温度Ｔｈを検出すると、制御手段１２は、減圧装置３の弁開度を大きくする（開く）とともに、制御手段１２からの信号で、状態記憶手段１５は、沸き上げ完了直前検出手段１３が沸き上げ完了の直前を検出したことを記憶する。そして、運転時間の経過とともに給水温度が更に上昇し、それに従って吐出圧力が上昇する。いま、運転時間ｔにおいて、貯湯槽５から出湯されると、出湯検出手段１８である出湯温度検出手段２１が出湯基準温度Ｔｏ以上の温度を検出することによって出湯を検知する。そして、タイマー１９は出湯している時間を計測する。このタイマー１９の計測した時間が所定の出湯時間ｔｏになると、制御手段１２は状態記憶手段１５の内容を検出する。そして、状態記憶手段１５の内容が、沸き上げ完了の直前を検出したことを記憶しておれば、減圧装置３の弁開度を小さくする（閉める）とともに、状態記憶手段１５は、沸き上げ完了直前検出手段１３が沸き上げ完了の直前を検出したという記憶を解除する（もし、状態記憶手段１５の内容が、沸き上げ完了の直前を検出したことを記憶していなければ、減圧装置３の弁開度の制御は行わない）。
【００３４】
以上のように、本実施例においては、沸き上げ完了直前検出手段として給水温度検出手段８を備え、沸き上げ完了直前解除手段として出湯温度検出手段２１とタイマー１９とを備えたことにより、沸き上げ完了に近づき、圧縮機１の吐出圧力が上昇する場合に、減圧装置３の弁開度を開くように制御し、吐出圧力を低く押さえ、高温の給水温度まで給湯加熱運転が可能となり、貯湯槽５の湯容量を有効に利用できるものである。その後、所定の時間の出湯を検出した場合には、減圧装置３の弁開度を閉じるように制御するので、効率の良い給湯加熱運転が可能となるものである。また、直接出湯温度を検出して制御するので、より確実性のある運転が可能である。
【００３５】
（実施例５）
図１１は本発明の実施例５のヒートポンプ給湯機の構成図、図１２は同ヒートポンプ給湯機の沸き上げ完了直前解除がある場合の運転時間に対する沸き上げ完了直前検出手段の検出状態と圧縮機の運転状態と減圧装置の弁開度と吐出圧力と貯湯槽の下部温度とを示すグラフである。本実施例において、実施例１と異なる点は、沸き上げ完了直前検出手段１３および沸き上げ完了直前解除手段１４として、貯湯槽５の下部温度を検出する貯湯槽温度検出手段２２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。
【００３６】
次に動作、作用について説明する。沸き上げ完了直前解除がある場合について説明する。図１２は、横軸に運転時間をとり、縦軸に沸き上げ完了直前検出手段１３の検出状態と圧縮機１の運転状態と減圧装置３の弁開度と吐出圧力と貯湯槽５の下部温度とをとって、運転時間に対する沸き上げ完了直前検出手段１３の検出状態と圧縮機１の運転状態と減圧装置３の弁開度と吐出圧力と貯湯槽５の下部温度との関係を示したものである。沸き上げ完了直前検出手段１３である貯湯槽温度検出手段２２が沸き上げ完了直前検出温度Ｔｈを検出すると、制御手段１２は、減圧装置３の弁開度を大きくする（開く）とともに、制御手段１２からの信号で、状態記憶手段１５は、沸き上げ完了直前検出手段１３が沸き上げ完了の直前を検出したことを記憶する。この時、吐出圧力はＰ１からＰ２に減少する。そして、運転時間の経過とともに貯湯槽の下部温度が更に上昇し、それに従って吐出圧力が上昇する。その後、運転時間ｔにおいて、貯湯槽５から出湯されるとともに冷たい水が給水管１６から貯湯槽５に流入すると、貯湯槽温度検出手段２２が検出する貯湯槽の下部温度も低下する。そして、ついに貯湯槽の下部温度が沸き上げ完了直前解除温度Ｔｒになると、制御手段１２は状態記憶手段１５の内容を検出する。そして、状態記憶手段１５の内容が、沸き上げ完了の直前を検出したことを記憶しておれば、減圧装置３の弁開度を小さくする（閉める）とともに、状態記憶手段１５は、沸き上げ完了直前検出手段１３が沸き上げ完了の直前を検出した記憶を解除する（もし、状態記憶手段１５の内容が、沸き上げ完了の直前を検出したことを記憶していなければ、減圧装置３の弁開度の制御は行わない）。その後、運転時間の経過とともに貯湯槽の下部温度が更に上昇し、沸き上げ完了直前検出手段１３である貯湯槽温度検出手段２２が、再度、沸き上げ完了直前検出温度Ｔｈを検出すると、制御手段１２は、再び、減圧装置３の弁開度を大きくするとともに、制御手段１２からの信号で、状態記憶手段１５は、沸き上げ完了直前検出手段１３が沸き上げ完了の直前を検出したことを記憶する。その後、運転時間の経過とともに貯湯槽の下部温度が更に上昇し、それに従って吐出圧力が上昇する。そして、貯湯槽温度検出手段２２が、貯湯槽の下部温度Ｔ３ａを検出すると、圧縮機を停止し、給湯加熱運転を終了する。
【００３７】
以上のように、本実施例においては、沸き上げ完了直前検出手段および沸き上げ完了直前解除手段として貯湯槽５の下部温度を検出する貯湯槽温度検出手段２２を備えたことにより、沸き上げ完了に近づき、圧縮機１の吐出圧力が上昇する場合に、減圧装置３の弁開度を開くように制御し、吐出圧力を低く押さえ、高温の給水温度まで給湯加熱運転が可能となり、貯湯槽５の湯容量を有効に利用できるものである。その後、出湯等で給水温度が低くなった場合には、減圧装置３の弁開度を閉じるように制御するので、効率の良い給湯加熱運転が可能となるものである。また、直接貯湯槽１の下部温度で制御するので、圧縮機１のより確実な耐久性の向上になるものである。
【００３８】
【発明の効果】
以上のように、請求項１から請求項５に記載の発明によれば、沸き上げ完了に近づき、圧縮機の吐出圧力が上昇する場合に、減圧装置の弁開度を変更し、吐出圧力を低く押さえ、高温の給水温度まで給湯加熱運転が可能となるので、有効な湯として利用できない無駄な領域がより少なくなるため、貯湯槽の湯容量を有効に利用できる。その結果、従来と同じ大きさの貯湯槽でより大きな給湯負荷を満足し、逆に、従来と同じ大きさの給湯負荷を満足するためには従来より小形の貯湯槽でよいので、設置の自由度が大きく、コスト低減にもなる。さらに、効率の良い給湯加熱運転ができるものである。その後、出湯等で給水温度が低くなった場合には、減圧装置３の弁開度を変更するので、効率の良い給湯加熱運転が可能となるものである。
【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沸き上げ完了直前解除がない場合の運転時間に対する沸き上げ完了直前検出手段の検出状態と圧縮機の運転状態と減圧装置の弁開度と吐出圧力と給水温度とを示すグラフ
【図３】同ヒートポンプ給湯機の貯湯槽の温度分布を示す説明図
【図４】同ヒートポンプ給湯機の沸き上げ完了直前解除がある場合の運転時間に対する沸き上げ完了直前検出手段の検出状態と圧縮機の運転状態と減圧装置の弁開度と吐出圧力と給水温度とを示すグラフ
【図５】本発明の実施例２のヒートポンプ給湯機を示す構成図
【図６】同ヒートポンプ給湯機の運転時間に対する沸き上げ完了直前検出手段の検出状態と圧縮機の運転状態と減圧装置の弁開度と吐出圧力とを示すグラフ
【図７】本発明の実施例３のヒートポンプ給湯機を示す構成図
【図８】同ヒートポンプ給湯機の運転時間に対する沸き上げ完了直前検出手段の検出状態と出湯の有無と減圧装置の弁開度と吐出圧力と給水温度とを示すグラフ
【図９】本発明の実施例４のヒートポンプ給湯機を示す構成図
【図１０】同ヒートポンプ給湯機の運転時間に対する沸き上げ完了直前検出手段の検出状態と出湯温度と減圧装置の弁開度と吐出圧力と給水温度とを示すグラフ
【図１１】本発明の実施例５のヒートポンプ給湯機を示す構成図
【図１２】同ヒートポンプ給湯機の沸き上げ完了直前解除がある場合の運転時間に対する沸き上げ完了直前検出手段の検出状態と圧縮機の運転状態と減圧装置の弁開度と吐出圧力と貯湯槽の下部温度とを示すグラフ
【図１３】従来例におけるヒートポンプ給湯機を示す構成図
【図１４】同ヒートポンプ給湯機の貯湯槽の温度分布を示す説明図
【図１５】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グラフ
【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
１０流量制御手段
１１流量調整弁
１２制御手段
１３沸き上げ完了直前検出手段
１４沸き上げ完了直前解除手段[0001]
BACKGROUND 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 shown in Japanese Patent Laid-Open No. 60-164157. FIG. 13 is a configuration diagram of a conventional heat pump water heater. In FIG. 13, a refrigerant circulation circuit including a compressor 1, a refrigerant-to-water heat exchanger 2, a decompression device 3, and an evaporator 4, a hot water tank 5, a circulation pump 6, the refrigerant-to-water heat exchanger 2, and an auxiliary heater 7 is connected to a hot water supply circuit, and the high-temperature and high-pressure superheated gas refrigerant discharged from the compressor 1 flows into the refrigerant-to-water heat exchanger 2 where the water sent from the circulation pump 6 is heated. To do. The condensed and liquefied refrigerant is decompressed by the decompression device 3 and flows into the evaporator 4, where it absorbs atmospheric heat to evaporate and returns to the compressor 1. On the other hand, the hot water heated in the refrigerant-to-water heat exchanger 2 flows into the upper part of the hot water storage tank 5 and is gradually stored from above. When the inlet water temperature of the refrigerant-to-water heat exchanger 2 reaches a set value, the feed water temperature detecting means 8 detects it, stops the heat pump operation by the compressor 1, and switches to the independent operation of the auxiliary heater 7. Is.
[0003]
[Problems to be solved by the invention]
  However, in the configuration of the conventional example as described above, a hot water mixed layer is formed at the portion where the hot water in the hot water tank 5 is in contact with water with the elapse of the boiling operation time, and the layer gradually expands. FIG. 14 shows the temperature distribution of hot water in the hot water tank 5. In the figure, T1 is the boiling temperature (high temperature hot water), and T2 is the city water temperature (low temperature hot water). The above-mentioned hot / cold mixed layer is generated by heat conduction and convection between hot and cold hot water, and heat is transferred from the hot water to the low temperature hot water. To rise. Therefore, when the boiling of the hot water storage tank 5 is nearly completed, the temperature of the feed water flowing into the refrigerant-to-water heat exchanger 2 increases, so that the discharge pressure of the compressor 1 rises and compression such as an increase in the winding temperature of the motor occurs. The durability of the machine 1 becomes an issue.
[0004]
  FIG. 15 shows the relationship between the discharge pressure of the compressor 1 with respect to the feed water temperature, with the horizontal axis representing the feed water temperature flowing into the refrigerant-to-water heat exchanger 2 and the vertical axis representing the discharge pressure of the compressor 1 at that time. It is a graph. The pressure P in the figure is a normal upper limit pressure, and in order to guarantee the durability of the compressor 1, it is necessary to operate at or below this pressure in normal operation. The water supply temperature at the pressure P is T3 from the figure. Further, the lower limit of the effective hot water temperature is Tu (for example, 45 ° C.), and T3 and Tu are shown in FIG. In the cross-sectional view of the hot water storage tank 5 shown on the left side of the figure, the area below the hot water temperature T3 is an area that can be heated, and the area above the Tu is an area that can be used as effective hot water. However, the region between the hot water temperatures T3 and Tu (shaded portion) is a region that cannot be used as effective hot water.
[0005]
  Thus, in the configuration of the conventional example, the operation is stopped in a state where the water temperature flowing through the refrigerant-to-water heat exchanger 2 is low.
Since it must be stopped, the lower part of the hot water tank 5 stops in a state of low-temperature water, and the hot water capacity of the hot water tank 5 cannot be used effectively. Therefore, the amount of stored hot water is reduced and the hot water supply load cannot be satisfied. One way to solve this is to increase the capacity of the hot water tank 5. However, in this case, there is a problem that the installation area of the hot water tank 5 is increased, the degree of freedom of installation is limited, and the cost is increased. As another method, there is a method of increasing the amount of stored hot water by the independent operation of the auxiliary heater 7 after stopping the heat pump operation. However, in this case, since heating is performed with a heater or the like, there is a problem that power consumption increases and efficiency decreases.
[0006]
  The present invention solves the above-described conventional problems, and can store hot water to the lower part of the hot water tank with low power consumption without any abnormal temperature rise and pressure rise of the compressor, and can effectively use the hot water capacity. The purpose is to provide a heat pump water heater.
[0007]
[Means for Solving the Problems]
  In order to solve the conventional problem, the heat pump water heater of the present invention isDuring the hot water heating operation that heats up the hot water tank, the detection temperature immediately before the completion of boiling is detected that is higher than the release temperature immediately before the completion of boiling before the time when the feed water temperature detecting means detects the release temperature immediately before the completion of boiling. If the valve opening of the pressure reducing device is increased, a control means is provided for controlling the valve opening of the pressure reducing device to be reduced when the feed water temperature detecting means detects the release temperature immediately before the completion of boiling. Is.
[0008]
  ThisWhen the discharge pressure of the compressor approaches the completion of boiling, the valve opening of the decompression device is controlled to open, and the discharge pressure is kept low, so hot water heating operation can be performed up to a high water supply temperature. Thereafter, when the feed water temperature becomes low due to hot water or the like, the valve opening degree of the pressure reducing device is controlled to be closed, so that an efficient hot water heating operation can be performed.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
  The invention described in claim 1A refrigerant circulation circuit connected with a variable capacity compressor, a refrigerant-to-water heat exchanger, a decompression device, and a hot water supply circuit for supplying water stored in the lower part of the hot water tank to the refrigerant-to-water heat exchanger and then flowing into the upper part of the hot water tank A water flow adjustment valve for controlling the flow rate of the hot water supply circuit to set the water-side outlet water temperature of the refrigerant-to-water heat exchanger to a predetermined value, and water supplied from the lower part of the hot water tank at the water-side inlet of the refrigerant-to-water heat exchanger During the hot water heating operation for boiling the hot water storage tank, the feed water temperature detecting means detects the release temperature immediately before the completion of boiling before the boiling temperature release temperature. However, if the detected temperature just before the completion of boiling is detected and the valve opening of the pressure reducing device is increased, the valve opening of the pressure reducing device is decreased when the feed water temperature detecting means detects the release temperature immediately before the completion of boiling. To control And a control meansTherefore, when the boiling pressure is nearing completion and the discharge pressure of the compressor rises, the valve opening of the decompression device is changed, the discharge pressure is kept low, and hot water heating operation can be performed up to a high water supply temperature. Since there are fewer wasted areas that cannot be used as hot water, the hot water capacity of the hot water tank can be used effectively.Furthermore, when the feed water temperature decreases due to hot water, etc. Since the control is performed so as to be closed, an efficient hot water supply heating operation is possible.
[0010]
  The invention described in claim 2A refrigerant circulation circuit connected with a variable capacity compressor, a refrigerant-to-water heat exchanger, a decompression device, and a hot water supply circuit for supplying water stored in the lower part of the hot water tank to the refrigerant-to-water heat exchanger and then flowing into the upper part of the hot water tank , A flow rate adjustment valve that controls the flow rate of the hot water supply circuit to set the water-side outlet water temperature of the refrigerant-to-water heat exchanger to a predetermined value, discharge pressure detection means that detects the discharge pressure of the compressor, and boiling of the hot water tank During the hot water heating operation, the discharge pressure detection means detects the detection pressure immediately before the completion of boiling, which is higher than the release pressure immediately before the completion of boiling, before the detection of the release pressure immediately before the completion of boiling. And a control means for controlling so that the valve opening of the pressure reducing device is reduced when the discharge pressure detecting means detects the release pressure immediately before the completion of boiling if the valve opening is increased.By controlling the discharge pressure directly and changing the valve opening of the optimum pressure reducing device according to the discharge pressure, the durability of the compressor is improved more reliably and more efficient hot water heating operation is possible. It can be done.
[0011]
  The invention according to claim 3A refrigerant circulation circuit connected with a variable capacity compressor, a refrigerant-to-water heat exchanger, a decompression device, and a hot water supply circuit for supplying water stored in the lower part of the hot water tank to the refrigerant-to-water heat exchanger and then flowing into the upper part of the hot water tank A water flow adjustment valve for controlling the flow rate of the hot water supply circuit to set the water-side outlet water temperature of the refrigerant-to-water heat exchanger to a predetermined value, and water supplied from the lower part of the hot water tank at the water-side inlet of the refrigerant-to-water heat exchanger During the hot water heating operation for heating the hot water storage tank, the hot water detection time for the hot water detection means is set to a predetermined time during the hot water heating operation for heating the hot water storage tank. If the detection means immediately before the completion of boiling is detected immediately before boiling, and the valve opening of the pressure reducing device is increased, the temperature of the pressure reducing device is increased when the time for detecting the hot water detected by the hot water detecting means is measured for a predetermined time. Small valve opening And control means for controlling the Kusuru soBecause the valve opening of the decompression device is changed at the time of detection just before the completion of boiling, the hot water capacity of the hot water tank can be used effectively and the hot water heating operation can be performed efficiently. When the detection just before the completion of boiling is canceled, the feed water temperature falls, and the valve opening of the pressure reducing device is changed, so that an efficient hot water heating operation is possible.
[0012]
  The invention described in claim 4 is provided with a hot water temperature detecting means for detecting the temperature of hot water discharged from the hot water tank as the hot water detection means, so that the hot water temperature detecting means detects the hot water temperature and detects the hot water. In some cases, since the feed water temperature is lowered, the valve opening degree of the pressure reducing device is controlled to be closed, so that an efficient hot water heating operation can be performed.
[0013]
  The invention described in claim 5A refrigerant circulation circuit connected with a variable capacity compressor, a refrigerant-to-water heat exchanger, a decompression device, and a hot water supply circuit for supplying water stored in the lower part of the hot water tank to the refrigerant-to-water heat exchanger and then flowing into the upper part of the hot water tank , A flow rate adjusting valve for controlling the flow rate of the hot water supply circuit to set the water-side outlet water temperature of the refrigerant-to-water heat exchanger to a predetermined value, hot water tank temperature detecting means for detecting the lower temperature of the hot water tank, and boiling of the hot water tank During hot water heating operation to raise the temperature, the hot water tank temperature detection means detects the detection temperature immediately before the completion of boiling that is higher than the release temperature immediately before the completion of boiling before detecting the release temperature immediately before the completion of boiling. If the valve opening degree of the apparatus is increased, the hot water tank temperature detecting means includes a control means for controlling the valve opening degree of the pressure reducing apparatus to be reduced when detecting the release temperature immediately before the completion of boiling.By directly detecting the hot water tank temperature and changing the valve opening of the optimum pressure reducing device according to the hot water tank temperature, the durability of the compressor can be improved more reliably and more efficiently. Hot water heating operation is possible.
[0014]
【Example】
  Embodiments of the present invention will be described below with reference to the drawings.
[0015]
  Example 1
  FIG. 1 is a block diagram of the heat pump water heater according to the first embodiment of the present invention, and FIG. 2 is a diagram showing the detection state of the heating means immediately before the completion of boiling and the compressor state with respect to the operation time when there is no release immediately before the boiling of the heat pump water heater. FIG. 3 is an explanatory diagram showing the temperature distribution of the hot water storage tank of the heat pump water heater, and FIG. 4 is just before completion of boiling of the heat pump water heater. It is a graph which shows the detection state of the detection means immediately before completion of boiling with respect to the operation time when there is a release, the operation state of the compressor, the valve opening degree of the decompression device, the discharge pressure, and the feed water temperature. In addition, the same code | symbol is used for the same component as FIG. 13 demonstrated in the prior art example, and description is abbreviate | omitted.
[0016]
  In FIG. 1, the flow rate control means 10 controls the opening degree of the flow rate adjustment valve 11 by a 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 The outlet water temperature (boiling temperature) of the exchanger 2 is boiled so as to be substantially constant. Further, the control means 12 is a signal from the boiling completion just before detection means 13 for detecting immediately before the completion of boiling, or a signal from the boiling completion immediately before releasing means 14 for canceling that the detection is immediately before the completion of boiling. Thus, the valve opening degree of the decompression device 3 is controlled. Further, the state storage means 15 stores whether or not the immediately before boiling completion detecting means 13 has detected the immediately before boiling completion, and 16 is a water supply pipe.
[0017]
  In addition, here, the feed water temperature detection means 8 that detects the feed water temperature that is the water-side inlet water temperature of the refrigerant-to-water heat exchanger 2 is used as the boiling completion just before detection means 13 and the boiling completion just before release means 14. The flow rate adjusting valve 11 includes an electric valve (not shown) driven by a stepping motor, and the pressure reducing device 3 includes an electric expansion valve (not shown).
[0018]
  Next, the operation and action will be described. First, a case where there is no cancellation immediately before completion of boiling will be described. FIG. 2 shows the operation time on the horizontal axis, the detection state of the detection means 13 immediately before the completion of boiling, the operation state of the compressor 1, the valve opening of the pressure reducing device 3, the discharge pressure, and the feed water temperature on the vertical axis. The relationship between the detection state of the detection means 13 immediately before the completion of boiling with respect to the operation time, the operation state of the compressor 1, the valve opening degree of the decompression device 3, the discharge pressure, and the feed water temperature is shown. As explained in the conventional example, when the boiling of the hot water tank 5 is nearly completed, the temperature of the feed water flowing into the refrigerant-to-water heat exchanger 2 increases. That is, when the water flowing into the refrigerant-to-water heat exchanger 2 becomes a part of the hot water / water mixture layer described above, the feed water temperature rises with the operation time as shown in FIG. When the feed water temperature detection means 8 which is the detection means 13 immediately before the completion of boiling detects the detection temperature Th immediately before the completion of boiling (which is lower than the boiling temperature T1), the control means 12 In addition to increasing (opening) the opening degree, the state storage means 15 stores that the immediately preceding boiling completion detection means 13 has detected that the boiling has just been completed by a signal from the control means 12. At this time, the discharge pressure decreases from P1 to P2. Thereafter, as the operation time elapses, the feed water temperature further rises, and the discharge pressure rises accordingly. And if the feed water temperature detection means 8 detects the feed water temperature T3a used as the normal upper limit pressure P, a compressor will be stopped and hot water supply heating operation will be complete | finished. In addition, the thick dotted line in the same figure is the case of the prior art example which does not control the valve opening degree of the decompression device 3. It can be seen that the water supply temperature at the operating limit increases from T3 to T3a, and the operating range increases. FIG. 3 shows the temperature distribution of hot water in the hot water tank 5. In the cross-sectional view of the hot water tank 5 shown on the left side of the figure, the area below the hot water temperature T3a is an area where boiling can be performed, and the area above the Tu is an area that can be used as effective hot water. In the case of the conventional example shown in FIG. 14, the region that cannot be used as effective hot water is the region between the hot water temperatures T3 and Tu. In the present embodiment, the region between the hot water temperatures T3a and Tu (hatched line). Part). That is, the region between the hot water temperatures T3 and T3a (the hatched portion by the dotted line) is the hot water region that has become effective according to this embodiment.
[0019]
  Next, a case where there is a release immediately before completion of boiling will be described. In FIG. 4, as in FIG. 2, the horizontal axis indicates the operation time, and the vertical axis indicates the detection state of the detection means 13 immediately before the completion of boiling, the operation state of the compressor 1, the valve opening degree and the discharge pressure of the decompression device 3. It shows the relationship between the detection state of the detection means 13 immediately before the completion of boiling, the operation state of the compressor 1, the valve opening degree of the pressure reducing device 3, the discharge pressure, and the supply water temperature by taking the supply water temperature. . As in the case described above, when the feed water temperature detection means 8 which is the detection means 13 immediately before the completion of boiling detects the detection temperature Th immediately before the completion of boiling, the control means 12 increases (opens) the valve opening of the decompression device 3. At the same time, with the signal from the control means 12, the state storage means 15 stores that the immediately preceding boiling completion detection means 13 has detected the immediately preceding boiling completion. At this time, the discharge pressure decreases from P1 to P2. As the operation time elapses, the feed water temperature further rises, and the discharge pressure rises accordingly. Thereafter, when the hot water is discharged from the hot water storage tank 5 and cold water flows into the hot water storage tank 5 from the water supply pipe 16 at the operation time t, the water supply temperature detected by the water supply temperature detecting means 8 is also lowered. Then, when the feed water temperature finally reaches the release temperature Tr immediately before the completion of boiling, the control means 12 detects the contents of the state storage means 15. And if the content of the state memory | storage means 15 memorize | stores that the immediately before boiling completion was detected, while reducing the valve opening degree of the decompression device 3, the state memory | storage means 15 will complete boiling. The memory immediately before the completion of boiling is detected by the immediately preceding detection means 13 is canceled (if the content of the state storage means 15 does not store the detection of immediately before the completion of boiling, the valve opening of the decompressor 3 is opened. Do not control the degree).
[0020]
  Thereafter, the feed water temperature further rises as the operation time elapses, and when the feed water temperature detection means 8 which is the detection means 13 immediately before the completion of boiling detects the detection temperature Th immediately before the completion of boiling, the control means 12 again While increasing the valve opening degree of the decompression device 3, the state storage means 15 stores that the immediately preceding boiling completion detecting means 13 has detected that the boiling has just been completed by a signal from the control means 12. Thereafter, as the operation time elapses, the feed water temperature further rises, and the discharge pressure rises accordingly. And if the feed water temperature detection means 8 detects feed water temperature T3a, a compressor will be stopped and hot water supply heating operation will be complete | finished.
[0021]
  As described above, in the present embodiment, the boiling just before detection means 13 for detecting just before the entire hot water tank 5 is boiled, and the just before boiling completion canceling means for canceling the detection immediately before the hot water tank 5 is completely boiled. 14 and when the signal from the detection means 13 immediately before the completion of boiling is a predetermined first signal, the valve opening of the decompression device 3 is opened, and then the signal from the release means 14 immediately before the completion of boiling is a predetermined first signal. And the control means 12 for controlling the valve opening of the decompression device 3 to close when the second signal is reached, the decompression device is approached when the discharge pressure of the compressor 1 rises when the boiling is approaching completion. 3 is controlled to open the valve opening, the discharge pressure is kept low, hot water supply heating operation is possible up to a high water supply temperature, and the hot water capacity of the hot water tank 5 can be used effectively. The water supply temperature is If it becomes Ku Since the control to close the valve opening of the pressure reducing device 3, in which good hot water supply heat efficient operation is possible.
[0022]
  In this embodiment, the circulation pump 6 is provided between the water-side inlet of the refrigerant-to-water heat exchanger 2 and the hot water storage tank 5, and the flow rate adjusting valve 11 is connected to the water of the circulation pump 6 and the refrigerant-to-water heat exchanger 2. Although provided between the inlet and the side inlet, the flow rate adjusting valve 11 may be provided between the inlet of the circulation pump 6 and the hot water tank 5, or the water side outlet and the hot water tank of the refrigerant-to-water heat exchanger 2. The same operation and effect as in the embodiment of FIG.
[0023]
  The refrigeration cycle may be a normal heat pump cycle in which the discharge pressure using the refrigerant-to-water heat exchanger 2 as a condenser is lower than the critical point, as described in the conventional example of FIG. A supercritical heat pump cycle in which the discharge pressure using the anti-water heat exchanger 2 as a gas cooler is higher than the critical point may be used.
[0024]
  (Example 2)
  FIG. 5 is a block diagram of the heat pump water heater according to the second embodiment of the present invention, and FIG. 6 is a detection state of the detection means immediately before completion of boiling with respect to the operation time of the heat pump water heater, the operating state of the compressor, and the valve opening of the pressure reducing device. It is a graph which shows discharge pressure.
[0025]
  In the present embodiment, the difference from the first embodiment is that a discharge pressure detection means 17 for detecting the discharge pressure of the compressor 1 is provided as the boiling completion detection means 13 and the heating completion release means 14. That is. In addition, the part of the same code | symbol as Example 1 has the same structure, and abbreviate | omits description.
[0026]
  Next, the operation and action will be described. In FIG. 6, the horizontal axis indicates the operation time, and the vertical axis indicates the detection state of the detection means 13 immediately before the completion of boiling, the operation state of the compressor 1, the valve opening of the decompression device 3, and the discharge pressure. The relationship between the detection state of the detection means 13 immediately before the completion of boiling, the operating state of the compressor 1, the valve opening degree of the decompression device 3, and the discharge pressure is shown. As described in the first embodiment, when the water flowing into the refrigerant-to-water heat exchanger 2 becomes part of the hot / cold water mixed layer, the water supply temperature rises with the operation time, and accordingly, as shown in FIG. Also rises. When the discharge pressure detection means 17 that is the detection means 13 immediately before the completion of boiling detects the detection pressure Ph immediately before the completion of boiling, the control means 12 increases (opens) the valve opening degree of the decompression device 3 and the control means. With the signal from 12, the state storage means 15 stores that the immediately before boiling completion detection means 13 has detected that the boiling has just been completed. At this time, the discharge pressure decreases. As the operation time elapses, the feed water temperature further rises, and the discharge pressure rises accordingly. Thereafter, when the hot water is discharged from the hot water storage tank 5 and cold water flows into the hot water storage tank 5 from the water supply pipe 16 at the operation time t, the discharge pressure detected by the discharge pressure detecting means 17 is also reduced. Then, when the discharge pressure finally reaches the release pressure Pr immediately before the completion of boiling, the control means 12 detects the contents of the state storage means 15. And if the content of the state memory | storage means 15 memorize | stores that the immediately before boiling completion was detected, while reducing the valve opening degree of the decompression device 3, the state memory | storage means 15 will complete boiling. The memory immediately before the completion of boiling is detected by the immediately preceding detection means 13 is canceled (if the content of the state storage means 15 does not store the detection of immediately before the completion of boiling, the valve opening of the decompressor 3 is opened. Do not control the degree). Thereafter, the discharge pressure also rises as the feed water temperature further rises as the operation time elapses. When the discharge pressure detection means 17 that is the detection means 13 immediately before the completion of boiling again detects the detection pressure Ph immediately before the completion of boiling, the control means 12 again increases the valve opening of the decompression device 3, By means of a signal from the control means 12, the state storage means 15 stores that the immediately before boiling completion detection means 13 has detected the immediately before boiling completion. Thereafter, as the operation time elapses, the feed water temperature further rises, and the discharge pressure rises accordingly. And if the discharge pressure detection means 17 detects the regular upper limit pressure P, a compressor will be stopped and hot water supply heating operation will be complete | finished.
[0027]
  As described above, in the present embodiment, the discharge pressure detection means is provided as the boiling immediately before completion detection means and the boiling completion immediately before release means, so that the discharge pressure of the compressor 1 increases as the boiling closes. In this case, the opening of the decompression device 3 is controlled to be opened, the discharge pressure is kept low, the hot water supply heating operation can be performed up to a high temperature of the hot water supply, and the hot water capacity of the hot water storage tank 5 can be used effectively. Thereafter, when the temperature of the feed water becomes low due to hot water or the like, the opening of the decompression device 3 is controlled to be closed, so that an efficient hot water heating operation can be performed. Moreover, since it controls by direct discharge pressure, the more reliable durability of the compressor 1 is improved.
[0028]
  (Example 3)
  FIG. 7 is a block diagram of a heat pump water heater according to a third embodiment of the present invention, and FIG. 8 is a detection state of detection means immediately before the completion of boiling with respect to the operation time of the heat pump water heater, presence or absence of hot water, valve opening of a pressure reducing device, and discharge It is a graph which shows a pressure and feed water temperature.
[0029]
  In the present embodiment, the difference from the first embodiment is that the hot water detection means 18 for detecting that the hot water has been discharged from the hot water storage tank 5 as the release means 14 immediately before the completion of boiling is detected and that the hot water detection means 18 has been discharged. In other words, a timer 19 for measuring time is provided. In addition, as the hot water detection means 18, here, flow detection means 20 for detecting the presence or absence of the flow of hot water is used. In addition, the part of the same code | symbol as Example 1 has the same structure, and abbreviate | omits description.
[0030]
  Next, the operation and action will be described. In FIG. 8, the horizontal axis represents the operation time, the vertical axis represents the detection state of the detection means 13 immediately before the completion of boiling, the presence or absence of hot water, the valve opening of the pressure reducing device 3, the discharge pressure, and the feed water temperature. The relationship between the detection state of the detection means 13 immediately before the completion of boiling, the presence or absence of hot water, the valve opening of the pressure reducing device 3, the discharge pressure, and the feed water temperature is shown. When the boiling of the hot water tank 5 is nearly completed, as described in the first embodiment, the water supply temperature rises with the operation time, and the discharge pressure rises accordingly, as shown in FIG. Then, when the feed water temperature detection means 8 which is the detection means 13 immediately before the completion of boiling detects the detection temperature Th immediately before the completion of boiling, the control means 12 increases (opens) the valve opening degree of the decompression device 3, and the control means. With the signal from 12, the state storage means 15 stores that the immediately before boiling completion detection means 13 has detected that the boiling has just been completed. At this time, the discharge pressure decreases. As the operation time elapses, the feed water temperature further rises, and the discharge pressure rises accordingly. Thereafter, when the hot water is discharged from the hot water storage tank 5 at the operation time t, the flow detection means 20 which is the hot water detection means 18 detects the flow of the hot water, and the timer 19 measures the time during which the hot water is discharged. When the time measured by the timer 19 reaches a predetermined hot water time to, the control means 12 detects the contents of the state storage means 15. And if the content of the state memory | storage means 15 memorize | stores that the immediately before boiling completion was detected, while reducing the valve opening degree of the decompression device 3, the state memory | storage means 15 will complete boiling. The memory that the immediately preceding detecting means 13 has detected that the boiling has been completed is canceled (if the content of the state storing means 15 does not store that the immediately preceding boiling has been detected, the valve of the decompressor 3 The opening is not controlled.)
[0031]
  As described above, in this embodiment, the feed water temperature detection means 8 is provided as the detection means immediately before the completion of boiling, and the flow detection means 20 and the timer 19 are provided as the release means immediately before the completion of boiling. When the discharge pressure of the compressor 1 rises, the valve opening of the decompression device 3 is controlled to be opened, the discharge pressure is kept low, and the hot water supply heating operation is possible up to a high water supply temperature. The hot water capacity can be used effectively. Thereafter, when hot water is detected for a predetermined time, the valve opening degree of the decompression device 3 is controlled to be closed, so that an efficient hot water supply heating operation is possible. In addition, since the presence or absence of direct hot water flow is detected and controlled, a more reliable operation is possible.
[0032]
  Example 4
  FIG. 9 is a block diagram of a heat pump water heater according to a fourth embodiment of the present invention, and FIG. 10 is a detection state of the detection means immediately before the completion of boiling with respect to the operation time of the heat pump water heater, a tapping temperature, a valve opening of a pressure reducing device, and a discharge pressure. It is a graph which shows water supply temperature. The present embodiment is different from the third embodiment in that a tapping temperature detecting means 21 for detecting the temperature of the hot water discharged from the hot water storage tank 5 is provided as the tapping detection means 18. In addition, the part of the same code | symbol as Example 3 has the same structure, and description is abbreviate | omitted.
[0033]
  Next, the operation and action will be described. In FIG. 10, the horizontal axis represents the operation time, and the vertical axis represents the detection state of the detection means 13 immediately before the completion of boiling, the hot water temperature, the valve opening of the pressure reducing device 3, the discharge pressure, and the feed water temperature. The relationship between the detection state of the detection means 13 immediately before the completion of boiling, the hot water temperature, the valve opening degree of the pressure reducing device 3, the discharge pressure, and the feed water temperature is shown. As described in the third embodiment, when the water flowing into the refrigerant-to-water heat exchanger 2 becomes a part of the hot water / mixed water layer, the feed water temperature rises with the operation time, and accordingly, as shown in FIG. Also rises. Then, when the feed water temperature detection means 8 which is the detection means 13 immediately before the completion of boiling detects the detection temperature Th immediately before the completion of boiling, the control means 12 increases (opens) the valve opening degree of the decompression device 3, and the control means. With the signal from 12, the state storage means 15 stores that the immediately before boiling completion detection means 13 has detected that the boiling has just been completed. As the operation time elapses, the feed water temperature further rises, and the discharge pressure rises accordingly. Now, when the hot water is discharged from the hot water storage tank 5 during the operation time t, the hot water temperature detecting means 21 serving as the hot water detecting means 18 detects the hot water by detecting a temperature equal to or higher than the hot water reference temperature To. The timer 19 measures the time during which the hot water is discharged. When the time measured by the timer 19 reaches a predetermined hot water time to, the control means 12 detects the contents of the state storage means 15. And if the content of the state memory | storage means 15 memorize | stores that the immediately before boiling completion was detected, while reducing the valve opening degree of the decompression device 3, the state memory | storage means 15 will complete boiling. The memory that the immediately preceding detecting means 13 has detected that the boiling has been completed is canceled (if the content of the state storing means 15 does not store that the immediately preceding boiling has been detected, the valve of the decompressor 3 The opening is not controlled.)
[0034]
  As described above, in the present embodiment, the feed water temperature detecting means 8 is provided as the detecting means immediately before the completion of boiling, and the hot water temperature detecting means 21 and the timer 19 are provided as the releasing means immediately before the completion of boiling. When the discharge pressure of the compressor 1 rises nearing completion, the valve opening of the decompression device 3 is controlled to be opened, the discharge pressure is kept low, and hot water heating operation is possible up to a high hot water supply temperature. The hot water capacity of 5 can be used effectively. Thereafter, when hot water is detected for a predetermined time, the valve opening degree of the decompression device 3 is controlled to be closed, so that an efficient hot water supply heating operation is possible. In addition, since the hot water temperature is directly detected and controlled, more reliable operation is possible.
[0035]
  (Example 5)
  FIG. 11 is a block diagram of a heat pump water heater according to a fifth embodiment of the present invention, and FIG. 12 shows the detection state of the immediately before boiling completion detection means relative to the operation time when there is a release immediately before the boiling completion of the heat pump water heater and the compressor. It is a graph which shows a driving | running state, the valve opening degree of a decompression device, discharge pressure, and the lower temperature of a hot water tank. In the present embodiment, the difference from the first embodiment is that a hot water tank temperature detecting means 22 for detecting the lower temperature of the hot water tank 5 is provided as the boiling immediately preceding detection means 13 and the boiling completion immediately before releasing means 14. It is that you are. In addition, the part of the same code | symbol as Example 1 has the same structure, and abbreviate | omits description.
[0036]
  Next, the operation and action will be described. A case where there is a release immediately before completion of boiling will be described. In FIG. 12, the abscissa indicates the operation time, and the ordinate indicates the detection state of the detection means 13 immediately before the completion of boiling, the operation state of the compressor 1, the valve opening degree of the decompression device 3, the discharge pressure, and the lower temperature of the hot water tank 5. The relationship between the detection state of the detection means 13 immediately before the completion of boiling with respect to the operation time, the operation state of the compressor 1, the valve opening of the pressure reducing device 3, the discharge pressure, and the lower temperature of the hot water tank 5 is shown. It is. When the hot water tank temperature detection means 22, which is the detection means 13 immediately before the completion of boiling, detects the detection temperature Th immediately before the completion of boiling, the control means 12 increases (opens) the valve opening of the decompression device 3, and the control means 12. The state storage means 15 stores that the immediately preceding boiling completion detection means 13 has detected the immediately preceding boiling completion. At this time, the discharge pressure decreases from P1 to P2. Then, as the operation time elapses, the lower temperature of the hot water tank further increases, and the discharge pressure increases accordingly. Thereafter, when the hot water is discharged from the hot water tank 5 and cold water flows into the hot water tank 5 from the water supply pipe 16 at the operation time t, the lower temperature of the hot water tank detected by the hot water tank temperature detecting means 22 is also lowered. And finally, when the lower temperature of the hot water storage tank becomes the release temperature Tr immediately before the completion of boiling, the control means 12 detects the contents of the state storage means 15. And if the content of the state memory | storage means 15 memorize | stores that the immediately before boiling completion was detected, while reducing the valve opening degree of the decompression device 3, the state memory | storage means 15 will complete boiling. The memory immediately before the completion of boiling is detected by the immediately preceding detection means 13 is canceled (if the content of the state storage means 15 does not store the detection of immediately before the completion of boiling, the valve opening of the decompressor 3 is opened. Do not control the degree). Thereafter, as the operating time elapses, the lower temperature of the hot water tank further rises, and when the hot water tank temperature detection means 22 which is the detection means 13 immediately before the completion of boiling detects the detection temperature Th immediately before the completion of boiling, the control means 12. Again, the valve opening of the decompression device 3 is increased, and the state storage means 15 stores that the detection immediately before the completion of boiling has been detected by the state storage means 15 with a signal from the control means 12. . Thereafter, as the operation time elapses, the lower temperature of the hot water tank further rises, and the discharge pressure rises accordingly. And if the hot water storage tank temperature detection means 22 detects the lower temperature T3a of a hot water storage tank, a compressor will be stopped and hot water supply heating operation will be complete | finished.
[0037]
  As described above, in the present embodiment, the hot water storage tank temperature detecting means 22 for detecting the lower temperature of the hot water tank 5 is provided as the boiling immediately preceding detection means and the boiling completion immediately before releasing means. When the discharge pressure of the compressor 1 rises, the valve opening of the decompression device 3 is controlled to open, the discharge pressure is kept low, hot water supply heating operation is possible up to a high water supply temperature, The hot water capacity can be used effectively. Thereafter, when the feed water temperature becomes low due to hot water or the like, the valve opening degree of the decompression device 3 is controlled to be closed, so that an efficient hot water supply heating operation is possible. Moreover, since it controls by the lower temperature of the hot water tank 1 directly, the more reliable durability of the compressor 1 is improved.
[0038]
【The invention's effect】
  As described above, according to the first to fifth aspects of the present invention, when the boiling pressure is approaching completion and the discharge pressure of the compressor increases, the valve opening of the decompression device is changed, and the discharge pressure is reduced. Since the hot water supply heating operation can be performed up to a high temperature of the hot water supply, it is possible to effectively use the hot water capacity of the hot water storage tank because there is less wasted area that cannot be used as effective hot water. As a result, the hot water storage tank of the same size as before can satisfy a larger hot water supply load. Conversely, in order to satisfy the hot water supply load of the same size as the conventional one, a smaller hot water tank can be used. The degree is large and the cost is reduced. Furthermore, an efficient hot water supply heating operation can be performed. Thereafter, when the feed water temperature becomes low due to hot water or the like, the valve opening degree of the decompression device 3 is changed, so that an efficient hot water supply heating operation is possible.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a heat pump water heater according to a first embodiment of the present invention.
FIG. 2 shows the detection state of the detection means immediately before the completion of boiling, the operation state of the compressor, the valve opening degree of the decompression device, the discharge pressure, and the feed water temperature with respect to the operation time when there is no release immediately before the completion of boiling of the heat pump water heater. Graph showing
FIG. 3 is an explanatory diagram showing temperature distribution in a hot water storage tank of the heat pump water heater
FIG. 4 shows the detection state of the detection means immediately before the completion of boiling, the operation state of the compressor, the valve opening of the pressure reducing device, the discharge pressure, and the feed water temperature with respect to the operation time when there is a release immediately before the completion of boiling of the heat pump water heater. Graph showing
FIG. 5 is a block diagram showing a heat pump water heater according to a second embodiment of the present invention.
FIG. 6 is a graph showing the detection state of the detection means immediately before completion of boiling, the operation state of the compressor, the valve opening degree of the decompression device, and the discharge pressure with respect to the operation time of the heat pump water heater.
FIG. 7 is a block diagram showing a heat pump water heater according to a third embodiment of the present invention.
FIG. 8 is a graph showing the detection state of the detection means immediately before the completion of boiling with respect to the operation time of the heat pump water heater, the presence or absence of hot water, the valve opening of the pressure reducing device, the discharge pressure, and the feed water temperature.
FIG. 9 is a block diagram showing a heat pump water heater according to a fourth embodiment of the present invention.
FIG. 10 is a graph showing a detection state of the detection means immediately before completion of boiling, a hot water temperature, a valve opening of a pressure reducing device, a discharge pressure, and a water supply temperature with respect to an operation time of the heat pump water heater.
FIG. 11 is a configuration diagram showing a heat pump water heater according to a fifth embodiment of the present invention.
FIG. 12 shows the detection state of the detection means immediately before the completion of boiling, the operation state of the compressor, the valve opening degree of the pressure reducing device, the discharge pressure, and the hot water tank of the heat pump water heater when there is a release immediately before the completion of boiling. Graph showing lower temperature
FIG. 13 is a configuration diagram showing a heat pump water heater in a conventional example.
FIG. 14 is an explanatory view showing the temperature distribution of the hot water storage tank of the heat pump water heater.
FIG. 15 is a graph showing discharge pressure with respect to feed water temperature of the heat pump water heater.
[Explanation of symbols]
  1 Compressor
  2 Refrigerant-to-water heat exchanger
  3 Pressure reducing device
  4 Evaporator
  5 Hot water storage tank
  6 Circulation pump
  10 Flow control means
  11 Flow control valve
  12 Control means
  13 Detection means immediately before completion of boiling
  14 Release means immediately before boiling is completed

Claims

A refrigerant circulation circuit connected to a variable capacity compressor, a refrigerant-to-water heat exchanger, a decompression device, and hot water supply for supplying water stored in the lower part of the hot water tank to the upper part of the hot water tank after being supplied to the refrigerant-to-water heat exchanger A circuit, a flow rate adjusting valve for controlling a flow rate of the hot water supply circuit to set a water-side outlet water temperature of the refrigerant-to-water heat exchanger to a predetermined value, and the hot water storage tank at a water-side inlet of the refrigerant-to-water heat exchanger During the hot water heating operation for heating the hot water tank , the water temperature detecting means for detecting the temperature of the water supplied from the lower part and before the time when the water temperature detecting means detects the release temperature immediately before the completion of boiling. If the detected temperature immediately before the completion of boiling is higher than the release temperature immediately before the completion of boiling and the valve opening of the pressure reducing device is increased, the feed water temperature detecting means sets the release temperature immediately before the completion of boiling. Detected The heat pump water heater and a control means for controlling so as to reduce the valve opening of the pressure reducing device.

A refrigerant circulation circuit connected to a variable capacity compressor, a refrigerant-to-water heat exchanger, a decompression device, and hot water supply for supplying water stored in the lower part of the hot water tank to the upper part of the hot water tank after being supplied to the refrigerant-to-water heat exchanger A circuit, a flow rate adjustment valve that controls the flow rate of the hot water supply circuit to set the water-side outlet water temperature of the refrigerant-to-water heat exchanger to a predetermined value, and discharge pressure detection means that detects the discharge pressure of the compressor, During the hot water heating operation for boiling the hot water tank, detection immediately before the completion of boiling that is higher than the release pressure immediately before the completion of boiling before the time when the discharge pressure detecting means detects the release pressure immediately before the completion of boiling Control that controls to reduce the valve opening of the pressure reducing device when the discharge pressure detecting means detects the release pressure immediately before the completion of boiling if the pressure is detected to increase the valve opening of the pressure reducing device means Heat pump water heater with a.

A refrigerant circulation circuit connected to a variable capacity compressor, a refrigerant-to-water heat exchanger, a decompression device, and hot water supply for supplying water stored in the lower part of the hot water tank to the upper part of the hot water tank after being supplied to the refrigerant-to-water heat exchanger A circuit, a flow rate adjusting valve for controlling a flow rate of the hot water supply circuit to set a water-side outlet water temperature of the refrigerant-to-water heat exchanger to a predetermined value, and the hot water storage tank at a water-side inlet of the refrigerant-to-water heat exchanger During the hot water heating operation for heating the hot water storage tank, the hot water detection means for detecting the temperature of the hot water supplied from the lower part, the hot water detection means for detecting the hot water from the hot water tank, and the hot water detection operation If the detection means immediately before the completion of boiling is detected immediately before boiling and the valve opening of the pressure reducing device is increased before the time when the hot water detection time by the means measures the predetermined time, the hot water detection by the discharge hot water detection means detection During the heat pump water heater and a control means for controlling so as to reduce the valve opening of the pressure reducing device when measuring a predetermined time.

The heat pump water heater according to claim 3, further comprising a hot water temperature detecting means for detecting a temperature of hot water discharged from the hot water storage tank as the hot water detecting means.

A refrigerant circulation circuit connected to a variable capacity compressor, a refrigerant-to-water heat exchanger, a decompression device, and hot water supply for supplying water stored in the lower part of the hot water tank to the upper part of the hot water tank after being supplied to the refrigerant-to-water heat exchanger A circuit, a flow rate adjusting valve for controlling the flow rate of the hot water supply circuit to set the water-side outlet water temperature of the refrigerant-to-water heat exchanger to a predetermined value, and hot water tank temperature detecting means for detecting a lower temperature of the hot water tank. In the hot water heating operation for boiling the hot water tank, the boiling completion is higher than the release temperature immediately before the completion of boiling before the time when the hot water tank temperature detecting means detects the release temperature immediately before the completion of boiling. If the valve opening degree of the pressure reducing device is increased by detecting the immediately preceding detected temperature, the valve opening degree of the pressure reducing device is reduced when the hot water tank temperature detecting means detects the release temperature immediately before the completion of boiling. Control Heat pump water heater and means.