JP2004156849A

JP2004156849A - Heat pump hot-water supply device

Info

Publication number: JP2004156849A
Application number: JP2002323457A
Authority: JP
Inventors: Tatsumura Mo; 立群毛; Takeji Watanabe; 竹司渡辺; Keijiro Kunimoto; 啓次郎國本; Satoshi Matsumoto; 松本　　聡; Ryuta Kondo; 龍太近藤; Nobuhiko Fujiwara; 宣彦藤原; Kazuhiko Marumoto; 一彦丸本
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2002-11-07
Filing date: 2002-11-07
Publication date: 2004-06-03

Abstract

<P>PROBLEM TO BE SOLVED: To provide an instantaneous water heater type heat pump hot-water supply device having a wide capacity width and capable of efficiently supplying hot water with favorable controllability. <P>SOLUTION: The heat pump hot-water supply device is provided with a refrigerant circulation circuit 20, a heat exchanger 25 provided with a water passage 26 exchanging heat with a radiator 22, a water supply pipe 27 supplying tap water to the water passage, a hot-water supply circuit 28 connected to a hot-water supply terminal 28a so as to pass water, and a first compressor 21a and a second compressor 21b with different capacities. By this the heat pump hot-water supply device with a wide capacity width, having compatibility between stability and responsiveness of hot-water supply control, and capable of efficiently supplying hot water can be provided. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、ヒートポンプ給湯装置に関するものである。
【０００２】
【従来の技術】
従来のヒートポンプ給湯装置としては、特許文献１に記載されているような給湯装置が提案されていた。このヒートポンプ給湯装置は図４に示すように、閉回路に構成される冷媒流路１で圧縮機２、放熱器３、減圧手段４、吸熱器５が接続された冷媒循環回路７と、放熱器３の冷媒流路ａ８と熱交換を行う水流路９を備えた熱交換器１０と、この水流路９に水道水を供給する給水管１１と、前記水流路９とシャワーや蛇口等の給湯端末１２とを接続する給湯回路１３と、給湯回路１３に設け給湯温度を検出する温度センサ１４と、圧縮機２の回転数を制御するインバータ１５を備え、圧縮機２を温度センサ１４の検出温度と設定温度との差に応じてインバータ１５の出力周波数を変換するようにしていた。すなわち従来の給湯装置では設定温度に対して給湯温度が低い場合は圧縮機２の回転数を上げ、給湯温度が高い場合は回転数を下げるように制御するようにしていた。
【０００３】
しかし、上記従来例の給湯装置の構成では、給湯時における給湯負荷が一定ではない。特に流量は使用者が給湯目的によってさまざまに変化させるために給湯負荷は大きく変ってしまう。例えば家庭用の給湯の場合、シャワーや風呂への湯張りに給湯する場合は１０〜２０Ｌ／ｍｉｎの大流量となるが、台所で食器を洗う場合や洗面への給湯では３〜５Ｌ／ｍｉｎと少流量である。また、季節による給水温度の変化によっても給湯負荷は大きく変る。
【０００４】
こうした流量や水温の変化により大きくかわる給湯負荷を、従来のヒートポンプ給湯装置のように単一の圧縮機の回転数を変えるだけで給湯熱量を制御しようとした場合に、まずシャワー等の大流量の給湯負荷に対応するために大型の圧縮機に大型の熱交換器や吸熱器が必用になる。しかし、こうした大型圧縮機では、回転数を下げて小さな給湯負荷に対して能力を低くしようとするには限界があり、低負荷に対応し切れない課題があった。
【０００５】
このように、従来のヒートポンプ給湯装置では、大型の装置で単一の圧縮機の回転数を変えるだけの制御では能力変更幅に限界があり、例えば冬場のシャワーと風呂の湯張りの同時使用といった大能力から、夏場の食器洗いなどの微小能力までの幅広い給湯能力をカバーできなかった。そのためシャワー温度が低下したり、食器洗いで熱い湯がでたりするなどの不都合がでる可能性があった。
【０００６】
また、気温や水温や給湯負荷によりヒートポンプサイクルの運転条件が変ると、運転効率も変化するが、従来のヒートポンプ給湯装置では給湯温度に応じて大型の圧縮機の回転数を変えるだけなので、温度立ち上がりが遅くなるだけでなく、給湯負荷が小さい場合でも大型圧縮機を運転するために機械損失が大きく運転効率の悪い条件で運転されていた。したがって条件によっては極端に効率が悪化し、能力が発揮できなくなるばかりでなく、ランニングコストも高いものなる可能性もあった。
【０００７】
以上のように従来のヒートポンプ給湯装置では給湯負荷や外気条件の大小に関わりなく単一の熱交換器や吸熱器に対して単一の圧縮機により運転を行うために幅広い給湯負荷への対応が困難であったり、応答性が悪化したり、効率が悪化するなどの問題があった。
【０００８】
【特許文献１】
特開平２−２２３７６７号公報
【０００９】
【発明が解決しようとする課題】
本発明は、上記従来の課題を解決するもので、広い能力幅を有し、制御性と効率のよい給湯ができるヒートポンプ給湯装置を提供することを目的とする。
【００１０】
【課題を解決するための手段】
本発明は上記課題を解決するために、本発明のヒートポンプ給湯装置は、容量の異なる第一圧縮機と第二圧縮機と放熱器と減圧手段と吸熱器とを含む冷媒循環回路と、放熱器と熱交換を行う水流路を備えた熱交換器と、水流路に水道水を供給する給水管と、水流路から給湯端末へと通水するように接続する給湯回路とからなるヒートポンプ給湯装置とする。
【００１１】
この発明によれば、幅広い給湯負荷や外気条件に応じて構成要素の運転台数や運転条件あるいは冷媒循環経路の運転条件を変更することで対応できる。
【００１２】
【発明の実施の形態】
請求項１に記載の発明のヒートポンプ給湯装置は、容量の異なる第一圧縮機と第二圧縮機と放熱器と減圧手段と吸熱器とを含む冷媒循環回路と、放熱器と熱交換を行う水流路を備えた熱交換器と、水流路に水道水を供給する給水管と、水流路から給湯端末へと通水するように接続する給湯回路とからなるヒートポンプ給湯装置とする。
【００１３】
この発明によれば、冷媒循環回路において、容量の異なる第一圧縮機と第二圧縮機とが設けられているので、運転台数を変えることにより冷媒循環回路の冷媒循環量や吐出圧力を幅広く可変できる。小さな給湯負荷が要求されている時に、容量の小さな圧縮機を作動させて対応し、大きいな給湯負荷が要求されるときに、容量の大きな圧縮機もしくわ容量の小さな圧縮機と容量の大きな圧縮機とを同時に動かして対応する。このように、大容量の圧縮機の回転数を落としても対応しきれない小さな給湯負荷が、小容量の圧縮機をもって対応させることによって、給湯負荷の変化に幅広く対応できる。したがって、例えば冬場のシャワーと風呂の湯張りの同時使用といった大能力から、夏場の食器洗いなどの微小能力までの幅広い給湯負荷に対応した給湯制御ができる。
【００１４】
請求項２に記載の発明のヒートポンプ給湯装置は、請求項１に記載の第一圧縮機と第二圧縮機とが並設されたものである。
【００１５】
この発明によれば、並設された第一圧縮機と第二圧縮機の運転を変えることにより冷媒循環回路の冷媒循環量や吐出圧力を幅広く可変でき、その結果熱交換器での水路の加熱量が幅広く制御できる。したがって、例えば冬場のシャワーと風呂の湯張りの同時使用といった大能力から、夏場の食器洗いなどの微小能力までの幅広い給湯負荷に対応した給湯制御ができる。
【００１６】
請求項３に記載の発明のヒートポンプ給湯装置は、請求項１または２に記載の第一圧縮機の冷媒吸入状態と第二圧縮機の冷媒吸入状態とを、第一圧縮機の冷媒吐出状態と第二圧縮機の冷媒吐出状態とをそれぞれ略同様にする平衡制御手段を備えたものである。
【００１７】
この発明によれば、平衡制御手段が第一圧縮機の冷媒吸入状態と第二圧縮機の冷媒吸入状態とを、第一圧縮機の冷媒吐出状態と第二圧縮機の冷媒吐出状態とをそれぞれ略同様にすることによって、第一圧縮機と第二圧縮機とが同様な吸入と吐出状態となり、安定した同時並列運転ができる。
【００１８】
請求項４に記載の発明のヒートポンプ給湯装置は、要求される負荷を判断する負荷判断手段と、この負荷判断手段に基づき請求項１〜３いずれか１項記載の第一圧縮機または第二圧縮機を選択起動させる起動制御手段を備えたものである。
【００１９】
この発明によれば、要求される負荷を判断する負荷判断手段に基づき第一圧縮機または第二圧縮機を選択起動させる起動制御手段を備えているので、給湯端末から要求される給湯負荷に応じて最適な起動制御ができる。よって、運転効率の向上が図れるとともに、立ち上がりが速くて要求される給湯負荷への応答時間短縮が可能となる。
【００２０】
請求項５に記載の発明のヒートポンプ給湯装置は、瞬時負荷を判断する負荷判断手段と、この負荷判断手段に基づき請求項１〜４いずれか１項記載の第一圧縮機または第二圧縮機の起動停止を制御する切替制御手段とを備えたものである。
【００２１】
この発明によれば、瞬時負荷を判断する負荷判断手段に基づき一圧縮機または第二圧縮機の起動停止を制御する切替制御手段とを備えているので、例えば使用中、給湯端末の給湯負荷が急激に変動した場合において、瞬時負荷を判断する負荷判断手段に基づき第一圧縮機または第二圧縮機の運転を制御し最適な起動停止切替制御ができるため、変動された給湯負荷へ速く応答でき適切な湯温で適切な湯量を提供することができる。
【００２２】
請求項６に記載の発明のヒートポンプ給湯装置は、請求項４または５に記載の負荷判断手段が、給水管を流れる給水温度を検出する給湯温度検出手段と給湯端末へ供給する温水の温度を設定する温度設定手段と水流路を流れる水の流量を計測流量検知手段の少なくともとどちらか一つを用いたものである。
【００２３】
この発明によれば、負荷判断手段が、給水管を流れる給水温度を検出する給湯温度検出手段と給湯端末へ供給する温水の温度を設定する温度設定手段と水流路を流れる水の流量を計測流量検知手段の少なくともとどちらか一つを用いたため、正確に給湯負荷を判断することができる。
【００２４】
請求項７に記載の発明のヒートポンプ給湯装置は、請求項１〜６のいずれか１項に記載の第一圧縮機を常時運転するようにしたものである。
【００２５】
この発明によれば、例えば容量の小さな第一圧縮機を常時運転するようにしているので、常時小さな給湯負荷に対応できるとともに、大きな給湯負荷の時、容量の大きな第二圧縮機と同時に運転して対応するため、第一圧縮機と第二圧縮機の最大出力をもって最大給湯負荷に対応し、第二圧縮機の容量及び最大出力を押さえることもできる。
【００２６】
請求項８に記載の発明のヒートポンプ給湯装置は、請求項１〜７のいずれか１項に記載の第一圧縮機の回転数を制御する第一圧縮機制御手段を備えたもので、第一圧縮機の能力を可変範囲内で調整できるので、第二圧縮機と合わせて幅広い給湯負荷に対応しながら、微細な湯温設定にも対応することができる。
【００２７】
請求項９に記載の発明のヒートポンプ給湯装置は、請求項１〜８のいずれか１項に記載の第二圧縮機の回転数を制御する第二圧縮機制御手段を備えたもので、第二圧縮機の能力を可変範囲内で調整できるので、例えば第一圧縮機制御手段を有する第一圧縮機と合わせて幅広い給湯負荷に対応しながら、より微細な湯温設定にも対応することができる。
【００２８】
請求項１０に記載の発明のヒートポンプ給湯装置は、請求項１〜９のいずれか１項に記載の大容量の第二圧縮機の最小出力は、小容量の第一圧縮機の最大出力に等しくもしくわ小さくしたものである。
【００２９】
この発明によれば、第二圧縮機の最小出力は第一圧縮機の最大出力に等しくもしくわ小さくしたことによって、給湯負荷が変動し第一圧縮機と第二圧縮機を切替えして運転する時、第一圧縮機と第二圧縮機が重複してカバーできる給湯負荷ゾンが存在するので、給湯負荷への対応を順調に行うことができる。
【００３０】
請求項１１に記載の発明のヒートポンプ給湯装置は、請求項１〜１０のいずれか１項に記載の第一圧縮機または第二圧縮機の冷媒の逆流防止手段を備えたもので、各圧縮機の吐出圧に差が生じても圧縮機の冷媒や潤滑油が逆流することを防止できる。
【００３１】
請求項１２に記載の発明のヒートポンプ給湯装置は、請求項１〜１１のいずれか１項に記載の第一圧縮機と第二圧縮機内の潤滑油の量を平準化する平準化手段を備えたもので、第一圧縮機と第二圧縮機の吐出圧に差が生じても圧縮機の冷媒や潤滑油が逆流することを防止できる。
【００３２】
請求項１３に記載の発明のヒートポンプ給湯装置は、請求項１〜１２のいずれか１項に記載の第一圧縮機と第二圧縮機とを同一断熱空間内に収納したもので、運転している第一圧縮機或いは第二圧縮機が発生した熱をもって、停止している第二圧縮機或いは第一圧縮機を暖機することになるので、停止中の圧縮機もすばやく起動でき所定の運転状態まで短時間で到達でき負荷変動への応答性を高めることができる。
【００３３】
請求項１４に記載の発明のヒートポンプ給湯装置は、請求項１〜１３のいずれか１項に記載の冷媒循環回路は、冷媒の圧力が臨界圧力以上となる超臨界ヒートポンプサイクルであり、前記臨界圧力以上に昇圧された冷媒により熱交換器の水流路の流水を加熱する構成である。
【００３４】
そして、熱交換器の放熱器を流れる冷媒は、圧縮機で臨界圧力以上に加圧されているので、熱交換器の水流路の流水により熱を奪われて温度低下しても凝縮することがない。したがって熱交換器全域で冷媒と水とに温度差を形成しやすくなり、高温の湯が得られ、かつ熱交換効率を高めることができる。
【００３５】
【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。なお、従来例および各実施例において、同じ構成、同じ動作をする部分については同一符号を付与し、詳細な説明を省略する。
【００３６】
（実施例１）
図１は本発明の実施例１におけるヒートポンプ式給湯装置の構成図である。図１において、２０は冷媒循環回路で、圧縮機群２１、放熱器２２、減圧手段２３、吸熱器２４が冷媒流路２０により閉回路に接続されている。この圧縮機群２１は容量が異なる第一圧縮機２１ａ、第二圧縮機２１ｂを並列に配置して構成しており、第一圧縮機２１ａの容量は第二圧縮機の容量と比べ小さくなっている。冷媒循環回路２０は、例えば炭酸ガス（ＣＯ_２）を冷媒として使用し、高圧側の冷媒圧力が冷媒の臨界圧以上となる超臨界ヒートポンプサイクルを使用している。そして第一圧縮機２１ａと第二圧縮機２１ｂは、それぞれに内蔵する電動モータ（図示せず）によって駆動され、吸引した冷媒を臨界圧力以上圧縮して吐出する。減圧手段２３はステッピングモータ（図示せず）により駆動する絞り弁で、冷媒流路抵抗を制御している。
【００３７】
また、２５は放熱器２２の冷媒流路と熱交換を行う水流路２６を備えた熱交換器である。この水流路２６に水道水を直接供給する給水管２７と、水流路２６から出湯される湯をシャワー２８ａや蛇口２８ｂ等より成る給湯端末へ通水させるための給湯回路２８が接続されている。
【００３８】
２９ａ、２９ｂは、第一圧縮機２１ａと第二圧縮機２１ｂの冷媒の逆流を防止するための逆流防止手段で、それぞれの圧縮機２１ａ、２１ｂ吐出側に設けた逆止弁より成っている。これは圧縮機２１ａ、２１ｂの運転を変更する際に、停止している圧縮機に冷媒が逆流して吐出圧が低下するのを防止し、各圧縮機２１ａ、２１ｂ内の潤滑油が不均一になるのを防止することができる。なお、ここでは逆止弁を用いたが、電磁弁や、モータ駆動の電動弁でもよい。
【００３９】
また、３０は第一圧縮機２１ａ、第二圧縮機２１ｂ内の潤滑油の量を平準化する平準化手段で、それぞれの圧縮機２１ａ、２１ｂの潤滑油を連通するパイプより構成している。
【００４０】
以上の構成において、その動作、作用について説明する。図１に示す実施例において、水道水が給水管２７から熱交換器２５内の水流路２６へ流れ、そこで放熱器２２の冷媒流路２２ａを流れる冷媒と熱交換し、温度上昇して所定の温度となり給湯端末２８ａや２８ｂへ給湯する。一方、放熱器２２で熱を奪われ温度低下した冷媒が放熱器を出た後、減圧手段である絞り弁２３を経て、低温低圧となり吸熱器２４へ流れる。そして、吸熱器２４で例えば大気熱などを吸収し、圧縮機群２１へ流れる。圧縮機群２１において、給湯端末２８ａや２８ｂへ供給される給湯負荷に応じて、第一圧縮機２１ａ単独または第二圧縮機２１ｂ単独あるいは第一圧縮機２１ａ、第二圧縮機２１ｂ同時に運転している。そこで、作動している圧縮機が圧縮機群２１へ流れる冷媒を吸引し臨界圧力以上となるように圧縮して吐出する。この吐出される高温高圧の冷媒が放熱器２２で給水管２７からの水道水と熱交換をし、温度低下して放熱器２２を流出する。このように、ＣＯ_２を冷媒とする超臨界ヒートポンプサイクルが形成され、水道水を加熱し給湯するヒートポンプ給湯装置が構成される。
【００４１】
そして、小容量の第一圧縮機２１ａと大容量の圧縮機２１ｂを並列に備えたことによって、第一圧縮機２１ａまたは第二圧縮機２１ｂを運転させることにより冷媒循環回路２０の冷媒循環量や吐出圧力を幅広く可変できる。例えば小さな給湯負荷が要求されている時に、容量の小さな第一圧縮機２１ａを作動させて対応し、大きいな給湯負荷が要求されるときに、容量の大きな第二圧縮機２１ｂもしくわ第一圧縮機２１ａと第二圧縮機２１ｂとを同時に動かして対応する。このように、大容量の圧縮機の回転数を落としても対応しきれない小さな給湯負荷が、小容量の第一圧縮機２１ａをもって対応させることによって、給湯負荷の変化に幅広く対応できる。したがって、例えば冬場のシャワーと風呂の湯張りの同時使用といった大能力から、夏場の食器洗いなどの微小能力までの幅広い給湯負荷に対応した給湯制御ができる。
【００４２】
また、このヒートポンプ給湯装置は、全給湯負荷範囲において、第一圧縮機２１ａを常時運転することによって、常時小さな給湯負荷に対応できるとともに、大きな給湯負荷が要求される時、容量の大きな第二圧縮機２１ｂと同時に運転して対応するため、第一圧縮機２１ａと第二圧縮機２１ｂの最大出力をもって最大給湯負荷に対応し、第二圧縮機２１ｂの容量及び最大出力を押さえることもできる。
【００４３】
また、第一圧縮機２１ａと第二圧縮機２１ｂ間の潤滑油の油面に差が生じても平準化手段３０によって、油面の高い圧縮機から油面の低い圧縮機へ潤滑油が流れて常に平準化される。したがって、潤滑油不足によって加圧機構が焼け付いたりするトラブルが解消される。
【００４４】
また、第一圧縮機２１ａと第二圧縮機２１ｂの吐出口に、それぞれ冷媒の逆流防止手段２９ａ、２９ｂを備えたことによって、運転していない圧縮機に冷媒や潤滑油が逆流することを防止し、また、各圧縮機の吐出圧に差が生じても圧縮機の冷媒や潤滑油が逆流することを防止できる。
【００４５】
（実施例２）
図２は本発明の実施例２におけるヒートポンプ給湯装置の構成図である。なお、実施例１の給湯装置と同一構造のものは同一符号を付与し、説明を省略する。
【００４６】
図２において、実施例１の構成と異なるところは、第一圧縮機２１ａの冷媒吸入状態と第二圧縮機２１ｂの冷媒吸入状態とを、第一圧縮機２１ａの冷媒吐出状態と第二圧縮機２１ｂの冷媒吐出状態とをそれぞれ略同様にする平衡制御手段３１と、第一圧縮機２１ａの回転数を制御する第一圧縮機制御手段３２ａと、第二圧縮機２１ｂの回転数を制御する第二圧縮機制御手段３２ｂとを備えたことである。また、図２において、３３は吸熱器２４における大気温度を検知する大気温検知手段、３４は給湯端末２８ａや２８ｂへ供給する温水温度を検知する湯温検知手段、３５ａ、３５ｂはそれぞれ第一圧縮機２１ａと第二圧縮機２１ｂの冷媒吐出状態例えば吐出圧力を検知する吐出状態検出手段、３６ａ、３６ｂはそれぞれ第一圧縮機２１ａと第二圧縮機２１ｂの冷媒吸入状態例えば吸入圧力を検知する吸入状態検出手段である。
【００４７】
以上の構成において、その動作、作用について説明する。第一圧縮機２１ａと第二圧縮機２１ｂが同時に並列運転する時、吐出状態検出手段３５ａ、３５ｂと吸入状態検出手段３６ａ、３６ｂがそれぞれ第一圧縮機２１ａと第二圧縮機２１ｂの吐出圧力と吸入圧力を検知し、検知信号を平衡制御手段３１へ送り、平衡制御手段３１でこれらの吐出圧力と吸入圧力を比較する。そして、例えば第一圧縮機２１ａと第二圧縮機２１ｂとの吐出圧力が同様とならない場合は、平衡制御手段３１から第一圧縮機制御手段３２ａあるいは第二圧縮機制御手段３２ｂへ修正指令を出し、第一圧縮機２１ａまたは第二圧縮機２１ｂの回転数を制御しそれぞれ圧縮機の吐出圧力を略同様にする。
【００４８】
また、大気温検知手段３３が大気温度を、湯温検知手段３４が湯温を検知し、これらの検知信号を平衡制御手段３１へ送り、平衡制御手段３１で第一圧縮機制御手段３２ａと第二圧縮機制御手段３２ｂから送ってきた第一圧縮機２１ａの回転数信号と第二圧縮機２１ｂの回転数信号とこれらの信号を合わせて、さらに経験値などに基づきそれぞれ圧縮機の冷媒吐出状態と吸入狂態を推定する。そして、この推定値に基づいて平衡制御手段３１から第一圧縮機制御手段３２ａあるいは第二圧縮機制御手段３２ｂへ修正指令を出し、第一圧縮機２１ａまたは第二圧縮機２１ｂの回転数を制御しそれぞれ圧縮機の吐出圧力を略同様にすることもできる。
【００４９】
このように、平衡制御手段３１が第一圧縮機２１ａの冷媒吸入状態と第二圧縮機２１ｂの冷媒吸入状態とを、第一圧縮機２１ａの冷媒吐出状態と第二圧縮機２１ｂの冷媒吐出状態とをそれぞれ略同様にすることによって、第一圧縮機２１ａと第二圧縮機２１ｂとが同様な吸入と吐出状態となり、安定した同時並列運転ができる。
【００５０】
また、第一圧縮機２１ａの回転数を制御する第一圧縮機制御手段３９と第二圧縮機２１ｂの回転数を制御する第二圧縮機制御手段４０とが設けられているため、第一圧縮機２１ａと第二圧縮機２１ｂがそれぞれ可変範囲内で調整できるので、幅広い給湯負荷に対応しながら、より微細な湯温設定に対応することができる。
【００５１】
（実施例３）
図３は本発明の実施例３におけるヒートポンプ給湯装置の構成図である。なお、実施例１の給湯装置と同一構造のものは同一符号を付与し、説明を省略する。
【００５２】
図３において、実施例１の構成と異なるところは、起動時または運転中において、給湯端末２８ａや２８ｂから要求される給湯負荷を判断する負荷判断手段３３と、この負荷判断手段３３に基づき第一圧縮機２１ａまたは第二圧縮機２１ｂを選択起動させる起動制御手段３４と、この負荷判断手段３３に基づき第一圧縮機２１ａまたは第二圧縮機２１ｂの切替を制御する切替制御手段３５とを備えたことと、第一圧縮機２１ａの最大出力は第二圧縮機２１ｂの最小出力に等しくもしくわ大きくしたことである。また、３６は給水管２７を流れる給水温度を検知する給水温度検知手段、３７は水流路を流れる水の流量を計測する流量検知手段、３８は給湯回路へ供給される温水の温度を検知する給湯温度検知手段、３９は給湯端末へ供給する温水の温度を設定する温度設定手段である。負荷判断手段３３はこの給水温度検知手段３６と流量検知手段３７と給湯温度検知手段３８と給湯温度設定手段３９とを用いて算出されるものである。
【００５３】
以上の構成において、その動作、作用について説明する。給湯端末２８ａまたは２８ｂが開くと、水道水が給水管２７から熱交換器２５へ流れ、吸熱し温度設定手段３９によって予め設定された温度となろうとする。この水道水の流量を流量検知手段３７が検知し負荷判断手段３３へ信号を送り、負荷判断手段３３で給水温度検知手段３６によって検知された給水温度と合わせて給湯負荷が算定される。この給湯負荷の算定値に基づいて起動制御手段３４が第一圧縮機２１ａ単独または第二圧縮機２１ｂ単独あるいは第一圧縮機２１ａと第二圧縮機２１ｂ順次起動させる。すなわち、給水管２７から水道水が流れ込むのに連動して給湯負荷に応じて、例えば小さな給湯負荷に対して第一圧縮機２１ａ単独を起動させ、大きな給湯負荷に対して第一圧縮機と第二圧縮機を順次起動させることによって、適切に圧縮機が動作し、ヒートポンプサイクルが運転されるものである。
【００５４】
このように、給湯端末２８ａまたは２８ｂから要求される給湯負荷に応じて最適な起動制御ができる。よって、運転効率の向上が図れるとともに、立ち上がりが速くて要求される給湯負荷への応答時間短縮が可能となる。
【００５５】
また、使用中において、給湯端末２８ａや２８ｂからの給湯負荷が急激に変動した場合、流量検知手段３７、給湯温度検知手段３８、温度設定手段３９などからの検知信号は負荷判断手段３３へ送り、変動前と変動後の瞬時負荷をそれぞれ算出比較する。そして、負荷判断手段３３で算出された結果に基づき第一圧縮機２１ａまたは第二圧縮機２１ｂの運転を制御し最適な起動停止切替制御ができるため、変動された給湯負荷へ速く応答でき適切な湯温で適切な湯量を提供することができる。
【００５６】
また、第一圧縮機２１ａの最大出力は第二圧縮機２１ｂの最小出力に等しくもしくわ大きくしたため、給湯負荷が変動し第一圧縮機２１ａと第二圧縮機２１ｂを切替えして運転する時、第一圧縮機２１ａと第二圧縮機２１ｂが重複してカバーできる給湯負荷ゾンが存在するので、給湯負荷への対応を順調に行うことができる。
【００５７】
上記各実施例では、ヒートポンプサイクルを、冷媒の圧力が臨界圧力以上となる超臨界ヒートポンプサイクルとしたが、もちろん一般の臨界圧力以下のヒートポンプサイクルでもよい。またこの場合、冷媒としてはフロンガス、アンモニアなどを用いても良い。
【００５８】
【発明の効果】
以上のように、本発明によれば、広い能力幅を有し、給湯制御の応答性と安定性が両立し、効率のよい給湯ができるヒートポンプ給湯装置を提供することができる。
【図面の簡単な説明】
【図１】本発明の実施例１におけるヒートポンプ給湯装置の構成図
【図２】本発明の実施例２におけるヒートポンプ給湯装置の構成図
【図３】本発明の実施例３におけるヒートポンプ給湯装置の構成図
【図４】従来のヒートポンプ給湯装置の構成図
【符号の説明】
２０冷媒循環回路
２１ａ第一圧縮機
２１ｂ第二圧縮機
２２、２２ａ、２２ｂ放熱器
２３、２３ａ、２３ｂ減圧手段
２４、２４ａ、２４ｂ吸熱器
２５熱交換器
２６水流路
２７給水管
２８給湯回路
２８ａ、２８ｂ給湯端末
２９ａ、２９ｂ逆流防止手段
３０平準化手段
３１平衡制御手段
３２ａ第一圧縮機制御手段
３２ｂ第二圧縮機制御手段
３３負荷判断手段
３４起動制御手段
３５切替制御手段
３６給水温度検知手段
３７流量検知手段
３９温度設定手段[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a heat pump water heater.
[0002]
[Prior art]
As a conventional heat pump hot water supply device, a hot water supply device as described in Patent Document 1 has been proposed. As shown in FIG. 4, this heat pump hot water supply apparatus has a refrigerant circulation circuit 7 in which a compressor 2, a radiator 3, a decompression means 4, and a heat absorber 5 are connected in a refrigerant flow path 1 formed in a closed circuit; A heat exchanger 10 having a water flow path 9 for performing heat exchange with the third refrigerant flow path a8, a water supply pipe 11 for supplying tap water to the water flow path 9, and a hot water supply terminal such as the water flow path 9 and a shower or a faucet. A hot water supply circuit 13 for connecting to the hot water supply circuit 12; a temperature sensor 14 provided in the hot water supply circuit 13 for detecting a hot water supply temperature; and an inverter 15 for controlling the number of revolutions of the compressor 2; The output frequency of the inverter 15 is converted according to the difference from the set temperature. That is, in the conventional hot water supply apparatus, when the hot water supply temperature is lower than the set temperature, the rotation speed of the compressor 2 is increased, and when the hot water supply temperature is high, the rotation speed is controlled to decrease.
[0003]
However, in the configuration of the conventional hot water supply apparatus, the hot water supply load during hot water supply is not constant. In particular, since the flow rate is varied by the user depending on the purpose of hot water supply, the hot water supply load greatly changes. For example, in the case of hot water for home use, a large flow rate of 10 to 20 L / min is required when hot water is supplied to a shower or bath, but 3 to 5 L / min when washing dishes in a kitchen or supplying hot water to a wash surface. Low flow rate. The hot water supply load also changes greatly due to seasonal changes in the water supply temperature.
[0004]
When the hot water supply load, which greatly changes due to such changes in flow rate and water temperature, is to be controlled by simply changing the rotation speed of a single compressor as in a conventional heat pump hot water supply device, a large flow rate such as a shower is first used. In order to cope with the hot water supply load, a large compressor requires a large heat exchanger and a heat sink. However, in such a large compressor, there is a limit to lowering the rotation speed to lower the capacity for a small hot water supply load, and there is a problem that it is difficult to cope with the low load.
[0005]
As described above, in the conventional heat pump hot water supply device, there is a limit to the capacity change width in the control of simply changing the rotation speed of a single compressor in a large-sized device, for example, simultaneous use of a shower in a winter and bathing in a bath. It could not cover a wide range of hot water supply capacity from large capacity to small capacity such as dishwashing in summer. For this reason, there is a possibility that the shower temperature may drop, or hot water may be generated during dishwashing, and the like.
[0006]
In addition, if the operating conditions of the heat pump cycle change due to the temperature, water temperature, and hot water supply load, the operating efficiency also changes.However, with the conventional heat pump hot water supply device, only the rotation speed of the large compressor is changed according to the hot water supply temperature. Not only slows down, but also when the hot water supply load is small, the large compressor is operated under conditions of large mechanical loss and poor operating efficiency. Therefore, depending on the conditions, the efficiency is extremely deteriorated, and not only the performance cannot be exhibited, but also the running cost may be high.
[0007]
As described above, in the conventional heat pump hot water supply system, a single heat exchanger or heat absorber is operated by a single compressor regardless of the size of the hot water supply load and the outside air condition, so that it can support a wide range of hot water load. There have been problems such as difficulty, responsiveness, and efficiency.
[0008]
[Patent Document 1]
JP-A-2-223767
[Problems to be solved by the invention]
An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a heat pump hot water supply apparatus having a wide capacity range, capable of controlling and supplying hot water efficiently.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a heat pump water heater, comprising: a refrigerant circulation circuit including a first compressor, a second compressor, a radiator, a pressure reducing unit, and a heat absorber having different capacities; A heat exchanger having a water flow path for performing heat exchange with a water pump, a water supply pipe for supplying tap water to the water flow path, and a heat pump hot water supply apparatus including a hot water supply circuit connected so that water flows from the water flow path to the hot water supply terminal. I do.
[0011]
According to the present invention, it is possible to respond by changing the number of operating components and operating conditions or operating conditions of the refrigerant circulation path according to a wide range of hot water supply load and outside air conditions.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
The heat pump water heater according to the first aspect of the present invention provides a refrigerant circulation circuit including a first compressor, a second compressor, a radiator, a pressure reducing means, and a heat absorber having different capacities, and a water flow for performing heat exchange with the radiator. The heat pump hot water supply apparatus includes a heat exchanger provided with a channel, a water supply pipe for supplying tap water to the water flow path, and a hot water supply circuit connected to the water flow path to the hot water supply terminal.
[0013]
According to the present invention, since the first and second compressors having different capacities are provided in the refrigerant circuit, the refrigerant circulation amount and the discharge pressure of the refrigerant circuit can be widely varied by changing the number of operating units. it can. When a small hot water supply load is required, a small capacity compressor is operated to respond.When a large hot water load is required, a large capacity compressor or a small capacity compressor and a large capacity compression are used. Move the machine at the same time to respond. As described above, a small-capacity compressor is used to cope with a small hot-water supply load that cannot be coped with even when the rotation speed of the large-capacity compressor is reduced. Therefore, it is possible to control hot water supply corresponding to a wide range of hot water supply loads from a large capacity such as simultaneous use of a shower and a hot water bath in winter to a small capacity such as dishwashing in summer.
[0014]
According to a second aspect of the present invention, there is provided a heat pump water heater in which the first compressor and the second compressor according to the first aspect are arranged in parallel.
[0015]
According to the present invention, by changing the operation of the first compressor and the second compressor arranged side by side, the amount of refrigerant circulated in the refrigerant circuit and the discharge pressure can be varied widely, and as a result, the heating of the water channel in the heat exchanger The amount can be controlled widely. Therefore, it is possible to control hot water supply corresponding to a wide range of hot water supply loads from a large capacity such as simultaneous use of a shower and a hot water bath in winter to a small capacity such as dishwashing in summer.
[0016]
According to a third aspect of the present invention, a heat pump water heater includes a refrigerant suction state of the first compressor and a refrigerant suction state of the second compressor according to the first or second aspect, and a refrigerant discharge state of the first compressor. It is provided with equilibrium control means for making the refrigerant discharge state of the second compressor substantially the same.
[0017]
According to the present invention, the balance control means sets the refrigerant suction state of the first compressor and the refrigerant suction state of the second compressor, and sets the refrigerant discharge state of the first compressor and the refrigerant discharge state of the second compressor, respectively. By making them substantially the same, the first compressor and the second compressor are in a similar suction and discharge state, and stable simultaneous parallel operation can be performed.
[0018]
According to a fourth aspect of the present invention, there is provided a heat pump hot water supply apparatus including: a load determining unit configured to determine a required load; and the first compressor or the second compressor according to any one of the first to third aspects, based on the load determining unit. It is provided with start control means for selectively starting the machine.
[0019]
According to the present invention, since the start control means for selectively starting the first compressor or the second compressor based on the load judgment means for judging the required load is provided, the start control means is provided in accordance with the hot water supply load requested from the hot water supply terminal. And optimal startup control can be performed. As a result, the operating efficiency can be improved, and the response time to the required hot water supply load can be shortened due to a quick start-up.
[0020]
According to a fifth aspect of the present invention, there is provided a heat pump hot water supply apparatus comprising: a load determining unit configured to determine an instantaneous load; and the first compressor or the second compressor according to any one of the first to fourth aspects, based on the load determining unit. Switching control means for controlling starting and stopping.
[0021]
According to the present invention, since there is provided the switching control means for controlling the start and stop of the first compressor or the second compressor based on the load determination means for determining the instantaneous load, for example, during use, the hot water supply load of the hot water supply terminal is reduced. In the case of a sudden change, the operation of the first compressor or the second compressor is controlled based on the load judgment means for judging the instantaneous load, and the optimal start / stop switching control can be performed. An appropriate amount of hot water can be provided at an appropriate temperature.
[0022]
According to a sixth aspect of the present invention, in the heat pump hot water supply apparatus, the load determining means according to the fourth or fifth aspect sets a hot water temperature detecting means for detecting a temperature of the hot water flowing through the water pipe and a temperature of the hot water supplied to the hot water terminal. At least one of the temperature setting means and the flow rate detecting means for measuring the flow rate of the water flowing through the water flow path is used.
[0023]
According to the present invention, the load determining means detects hot water temperature flowing through the water pipe, hot water temperature detecting means, temperature setting means for setting the temperature of hot water supplied to the hot water supply terminal, and measures the flow rate of water flowing through the water flow path. Since at least one of the detection means is used, the hot water supply load can be accurately determined.
[0024]
According to a seventh aspect of the present invention, there is provided a heat pump hot water supply apparatus in which the first compressor according to any one of the first to sixth aspects is constantly operated.
[0025]
According to the present invention, for example, since the first compressor having a small capacity is always operated, it is possible to always cope with a small hot water supply load, and is operated simultaneously with the second compressor having a large capacity at a large hot water load. Therefore, the maximum output of the first compressor and the second compressor can correspond to the maximum hot water supply load, and the capacity and the maximum output of the second compressor can be suppressed.
[0026]
An eighth aspect of the present invention provides a heat pump hot water supply apparatus comprising a first compressor control means for controlling a rotation speed of the first compressor according to any one of the first to seventh aspects. Since the capacity of the compressor can be adjusted within a variable range, it is possible to cope with a wide range of hot water supply load together with the second compressor and also to cope with a minute hot water temperature setting.
[0027]
A heat pump hot water supply apparatus according to a ninth aspect of the present invention includes a second compressor control unit that controls a rotation speed of the second compressor according to any one of the first to eighth aspects. Since the capacity of the compressor can be adjusted within a variable range, for example, it is possible to cope with a wider range of hot water supply load together with the first compressor having the first compressor control means and also to cope with finer hot water temperature setting. .
[0028]
In the heat pump hot water supply apparatus according to the tenth aspect, the minimum output of the large capacity second compressor according to any one of the first to ninth aspects is equal to the maximum output of the small capacity first compressor. If the hoes are smaller.
[0029]
According to the present invention, the minimum output of the second compressor is made equal to or smaller than the maximum output of the first compressor, so that the hot water supply load fluctuates and the first compressor and the second compressor are switched to operate. At this time, since there is a hot water supply load zone that the first compressor and the second compressor can cover in an overlapping manner, it is possible to smoothly cope with the hot water supply load.
[0030]
A heat pump hot water supply apparatus according to an eleventh aspect of the present invention includes the means for preventing a refrigerant from flowing back of the first compressor or the second compressor according to any one of the first to tenth aspects. Even if there is a difference in the discharge pressure of the compressor, it is possible to prevent the refrigerant and the lubricating oil of the compressor from flowing back.
[0031]
A heat pump hot water supply apparatus according to a twelfth aspect of the present invention includes a leveling means for leveling the amount of lubricating oil in the first compressor and the second compressor according to any one of the first to eleventh aspects. Thus, even if a difference occurs between the discharge pressures of the first compressor and the second compressor, it is possible to prevent the refrigerant and the lubricating oil of the compressor from flowing backward.
[0032]
A heat pump hot water supply apparatus according to a thirteenth aspect is a heat pump hot water supply apparatus in which the first compressor and the second compressor according to any one of the first to twelfth aspects are housed in the same adiabatic space. With the heat generated by the first compressor or the second compressor, the stopped second compressor or the first compressor is warmed up. The state can be reached in a short time, and the responsiveness to a load change can be improved.
[0033]
The heat pump hot water supply apparatus of the invention according to claim 14, wherein the refrigerant circulation circuit according to any one of claims 1 to 13 is a supercritical heat pump cycle in which the pressure of the refrigerant is equal to or higher than a critical pressure, The configuration is such that the flowing water in the water flow path of the heat exchanger is heated by the pressurized refrigerant.
[0034]
Since the refrigerant flowing through the radiator of the heat exchanger is pressurized to a critical pressure or higher by the compressor, the refrigerant may condense even if the temperature is lowered due to the loss of heat by the flowing water in the water flow path of the heat exchanger. Absent. Therefore, it is easy to form a temperature difference between the refrigerant and the water in the entire region of the heat exchanger, so that hot water can be obtained and the heat exchange efficiency can be improved.
[0035]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the conventional example and each embodiment, the same reference numerals are given to portions having the same configuration and the same operation, and detailed description will be omitted.
[0036]
(Example 1)
FIG. 1 is a configuration diagram of a heat pump hot water supply apparatus according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 20 denotes a refrigerant circulation circuit, in which a compressor group 21, a radiator 22, a pressure reducing means 23, and a heat absorber 24 are connected in a closed circuit by a refrigerant flow path 20. This compressor group 21 is configured by arranging a first compressor 21a and a second compressor 21b having different capacities in parallel, and the capacity of the first compressor 21a is smaller than the capacity of the second compressor. I have. The refrigerant circuit 20 uses, for example, carbon dioxide gas (CO ₂ ) as a refrigerant, and uses a supercritical heat pump cycle in which the refrigerant pressure on the high pressure side is equal to or higher than the critical pressure of the refrigerant. The first compressor 21a and the second compressor 21b are driven by electric motors (not shown) incorporated therein, respectively, and compress and discharge the sucked refrigerant at a critical pressure or higher. The pressure reducing means 23 is a throttle valve driven by a stepping motor (not shown), and controls the refrigerant flow path resistance.
[0037]
Reference numeral 25 denotes a heat exchanger provided with a water flow path 26 for performing heat exchange with the refrigerant flow path of the radiator 22. A water supply pipe 27 for directly supplying tap water to the water flow path 26 and a hot water supply circuit 28 for passing hot water from the water flow path 26 to a hot water supply terminal including a shower 28a and a faucet 28b are connected.
[0038]
Reference numerals 29a and 29b denote backflow preventing means for preventing backflow of the refrigerant in the first compressor 21a and the second compressor 21b, and are constituted by check valves provided on the discharge sides of the respective compressors 21a and 21b. This prevents the refrigerant from flowing backward to the stopped compressor and lowering the discharge pressure when the operation of the compressors 21a and 21b is changed, and the lubricating oil in each of the compressors 21a and 21b becomes uneven. Can be prevented. Although a check valve is used here, a solenoid valve or a motor-driven electric valve may be used.
[0039]
Reference numeral 30 denotes leveling means for leveling the amount of lubricating oil in the first compressor 21a and the second compressor 21b, and is constituted by a pipe for communicating the lubricating oil of each of the compressors 21a and 21b.
[0040]
The operation and operation of the above configuration will be described. In the embodiment shown in FIG. 1, tap water flows from a water supply pipe 27 to a water flow path 26 in a heat exchanger 25, where it exchanges heat with a refrigerant flowing through a refrigerant flow path 22a of a radiator 22, and the temperature rises to a predetermined level. It becomes temperature and supplies hot water to hot water supply terminals 28a and 28b. On the other hand, the refrigerant whose temperature has been reduced due to heat deprived by the radiator 22 exits the radiator, and then flows through the throttle valve 23 as a pressure reducing means to a low temperature and low pressure to the heat absorber 24. Then, the heat absorber 24 absorbs, for example, atmospheric heat and flows to the compressor group 21. In the compressor group 21, the first compressor 21a alone or the second compressor 21b alone, or the first compressor 21a and the second compressor 21b are simultaneously operated according to the hot water supply load supplied to the hot water supply terminals 28a and 28b. I have. Therefore, the operating compressor sucks the refrigerant flowing to the compressor group 21, compresses the refrigerant to a pressure equal to or higher than the critical pressure, and discharges the compressed refrigerant. The discharged high-temperature and high-pressure refrigerant exchanges heat with the tap water from the water supply pipe 27 in the radiator 22, and the temperature drops to flow out of the radiator 22. In this way, a supercritical heat pump cycle using CO ₂ as a refrigerant is formed, and a heat pump hot water supply device for heating tap water and supplying hot water is configured.
[0041]
And, by providing the first compressor 21a of small capacity and the compressor 21b of large capacity in parallel, by operating the first compressor 21a or the second compressor 21b, the refrigerant circulation amount of the refrigerant circuit 20 The discharge pressure can be varied widely. For example, when a small hot water supply load is required, the first compressor 21a having a small capacity is operated to cope with the demand. When a large hot water load is required, the second compressor 21b having a large capacity is also used. The compressor 21a and the second compressor 21b are simultaneously operated to correspond. As described above, by using the small capacity first compressor 21a to cope with a small hot water supply load that cannot be coped with even when the rotation speed of the large capacity compressor is reduced, it is possible to widely cope with a change in the hot water supply load. Therefore, it is possible to control hot water supply corresponding to a wide range of hot water supply loads from a large capacity such as simultaneous use of a shower and a hot water bath in winter to a small capacity such as dishwashing in summer.
[0042]
Further, this heat pump hot water supply apparatus can always cope with a small hot water supply load by constantly operating the first compressor 21a in the entire hot water load range, and when a large hot water supply load is required, the second compressor 21 having a large capacity. Since the operation is performed simultaneously with the compressor 21b, the maximum output of the first compressor 21a and the second compressor 21b corresponds to the maximum hot water supply load, and the capacity and the maximum output of the second compressor 21b can be suppressed.
[0043]
Even if a difference occurs in the oil level of the lubricating oil between the first compressor 21a and the second compressor 21b, the lubricating oil flows from the compressor having a high oil level to the compressor having a low oil level by the leveling means 30. And is always leveled. Therefore, the trouble that the pressurizing mechanism is seized due to lack of lubricating oil is solved.
[0044]
In addition, since the discharge ports of the first compressor 21a and the second compressor 21b are provided with the backflow prevention means 29a and 29b, respectively, the refrigerant and the lubricating oil are prevented from flowing back to the compressor that is not operating. Further, even if a difference occurs in the discharge pressure of each compressor, it is possible to prevent the refrigerant and the lubricating oil of the compressor from flowing back.
[0045]
(Example 2)
FIG. 2 is a configuration diagram of a heat pump hot water supply apparatus according to Embodiment 2 of the present invention. The same components as those of the hot water supply device of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
[0046]
In FIG. 2, the difference from the configuration of the first embodiment is that the refrigerant suction state of the first compressor 21a and the refrigerant suction state of the second compressor 21b are different from the refrigerant discharge state of the first compressor 21a and the second compressor 21a. An equilibrium control means 31 for making the refrigerant discharge states of the first compressor 21b substantially the same, a first compressor control means 32a for controlling the rotational speed of the first compressor 21a, and a second control means for controlling the rotational speed of the second compressor 21b. That is, two compressor control means 32b are provided. In FIG. 2, reference numeral 33 denotes an atmospheric temperature detecting means for detecting the atmospheric temperature in the heat absorber 24, reference numeral 34 denotes a hot water temperature detecting means for detecting the temperature of hot water supplied to the hot water supply terminals 28a and 28b, and reference numerals 35a and 35b denote first compression, respectively. State detection means for detecting the refrigerant discharge state, for example, the discharge pressure of the compressor 21a and the second compressor 21b, and the suction for detecting the refrigerant suction state, for example, the suction pressure of the first compressor 21a and the second compressor 21b, respectively. It is a state detecting means.
[0047]
The operation and operation of the above configuration will be described. When the first compressor 21a and the second compressor 21b are operated in parallel at the same time, the discharge state detecting means 35a, 35b and the suction state detecting means 36a, 36b respectively determine the discharge pressure of the first compressor 21a and the second compressor 21b. The suction pressure is detected, a detection signal is sent to the balance control means 31, and the discharge pressure and the suction pressure are compared by the balance control means 31. If the discharge pressures of the first compressor 21a and the second compressor 21b are not the same, for example, the balance controller 31 issues a correction command to the first compressor controller 32a or the second compressor controller 32b. , The number of revolutions of the first compressor 21a or the second compressor 21b is controlled to make the discharge pressures of the compressors substantially the same.
[0048]
The ambient temperature detecting means 33 detects the atmospheric temperature, and the hot water temperature detecting means 34 detects the hot water temperature, and sends these detection signals to the balance control means 31. The balance control means 31 and the first compressor control means 32a The rotational speed signal of the first compressor 21a and the rotational speed signal of the second compressor 21b sent from the second compressor control means 32b are combined with these signals, and the refrigerant discharge state of each compressor is further determined based on empirical values and the like. And infer madness. Then, a correction command is issued from the balance control means 31 to the first compressor control means 32a or the second compressor control means 32b based on the estimated value to control the rotation speed of the first compressor 21a or the second compressor 21b. The discharge pressures of the compressors can be made substantially the same.
[0049]
As described above, the balance control means 31 determines the refrigerant suction state of the first compressor 21a and the refrigerant suction state of the second compressor 21b by changing the refrigerant discharge state of the first compressor 21a and the refrigerant discharge state of the second compressor 21b. Are substantially the same, the first compressor 21a and the second compressor 21b are in the same suction and discharge state, and stable simultaneous parallel operation can be performed.
[0050]
Further, since the first compressor control means 39 for controlling the rotation speed of the first compressor 21a and the second compressor control means 40 for controlling the rotation speed of the second compressor 21b are provided, the first compression Since the compressor 21a and the second compressor 21b can be adjusted within the respective variable ranges, it is possible to cope with a finer hot water temperature setting while coping with a wide range of hot water supply load.
[0051]
(Example 3)
FIG. 3 is a configuration diagram of a heat pump hot water supply apparatus according to Embodiment 3 of the present invention. The same components as those of the hot water supply device of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
[0052]
In FIG. 3, a difference from the configuration of the first embodiment is that a load determining unit 33 that determines a hot water supply load required from the hot water supply terminals 28 a and 28 b at the time of startup or during operation, and a first determination based on the load determining unit 33. A start control unit 34 for selectively starting the compressor 21a or the second compressor 21b and a switching control unit 35 for controlling switching of the first compressor 21a or the second compressor 21b based on the load determining unit 33 are provided. That is, the maximum output of the first compressor 21a is equal to or larger than the minimum output of the second compressor 21b. Reference numeral 36 denotes water supply temperature detection means for detecting the temperature of water supply flowing through the water supply pipe 27; 37, flow rate detection means for measuring the flow rate of water flowing through the water flow path; 38, hot water supply for detecting the temperature of hot water supplied to the hot water supply circuit The temperature detecting means 39 is a temperature setting means for setting the temperature of the hot water supplied to the hot water supply terminal. The load determining means 33 is calculated using the supplied water temperature detecting means 36, the flow rate detecting means 37, the supplied hot water temperature detecting means 38 and the supplied water temperature setting means 39.
[0053]
The operation and operation of the above configuration will be described. When the hot water supply terminal 28a or 28b is opened, the tap water flows from the water supply pipe 27 to the heat exchanger 25, absorbs heat, and tries to reach a temperature preset by the temperature setting means 39. The flow rate detecting means 37 detects the flow rate of the tap water and sends a signal to the load determining means 33. The load determining means 33 calculates the hot water supply load together with the feed water temperature detected by the feed water temperature detecting means 36. The activation control means 34 activates the first compressor 21a alone or the second compressor 21b alone or sequentially activates the first compressor 21a and the second compressor 21b based on the calculated value of the hot water supply load. That is, the first compressor 21a alone is started for a small hot water supply load in response to the hot water supply load in conjunction with the flow of tap water from the water supply pipe 27, and the first compressor 21a and the second compressor 21 are started for a large hot water load. By sequentially starting the two compressors, the compressors operate properly and the heat pump cycle is operated.
[0054]
In this way, optimal startup control can be performed according to the hot water supply load required from hot water supply terminal 28a or 28b. As a result, the operating efficiency can be improved, and the response time to the required hot water supply load can be shortened due to a quick start-up.
[0055]
In addition, when the hot water supply load from the hot water supply terminals 28a and 28b fluctuates rapidly during use, detection signals from the flow rate detecting means 37, the hot water temperature detecting means 38, the temperature setting means 39, and the like are sent to the load determining means 33, The instantaneous loads before and after the change are calculated and compared. Then, since the operation of the first compressor 21a or the second compressor 21b is controlled based on the result calculated by the load determining means 33 and the optimal start / stop switching control can be performed, the apparatus can quickly respond to the fluctuated hot water supply load, and An appropriate amount of hot water can be provided at the hot water temperature.
[0056]
Further, since the maximum output of the first compressor 21a is equal to or larger than the minimum output of the second compressor 21b, when the hot water supply load fluctuates and the first compressor 21a and the second compressor 21b are switched and operated, Since there is a hot water supply load zone that the first compressor 21a and the second compressor 21b can cover in an overlapping manner, it is possible to smoothly cope with the hot water supply load.
[0057]
In each of the above embodiments, the heat pump cycle is a supercritical heat pump cycle in which the pressure of the refrigerant is equal to or higher than the critical pressure. In this case, as the refrigerant, Freon gas, ammonia, or the like may be used.
[0058]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a heat pump hot water supply apparatus that has a wide capacity range, achieves both responsiveness and stability of hot water supply control, and can supply hot water efficiently.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a heat pump hot water supply device according to a first embodiment of the present invention. FIG. 2 is a configuration diagram of a heat pump hot water supply device according to a second embodiment of the present invention. FIG. FIG. 4 is a configuration diagram of a conventional heat pump hot water supply apparatus.
Reference Signs List 20 refrigerant circulation circuit 21a first compressor 21b second compressor 22, 22a, 22b radiator 23, 23a, 23b decompression means 24, 24a, 24b heat absorber 25 heat exchanger 26 water flow path 27 water supply pipe 28 hot water supply circuit 28a, 28b Hot water supply terminals 29a, 29b Backflow prevention means 30 Leveling means 31 Balancing control means 32a First compressor control means 32b Second compressor control means 33 Load judgment means 34 Start-up control means 35 Switching control means 36 Water supply temperature detection means 37 Flow rate Detection means 39 temperature setting means

Claims

A heat exchanger including a first compressor, a second compressor having a capacity different from that of the first compressor, a radiator, a refrigerant circulation circuit including a decompression unit, and a heat absorber, and a water flow path performing heat exchange with the radiator. A heat pump hot water supply apparatus comprising: a water supply pipe that supplies tap water to the water flow path; and a hot water supply circuit that connects the water flow path to a hot water supply terminal.

The heat pump hot water supply device according to claim 1, wherein the first compressor and the second compressor are provided side by side.

Equilibrium control means is provided for making the refrigerant suction state of the first compressor and the refrigerant suction state of the second compressor substantially the same as the refrigerant discharge state of the first compressor and the refrigerant discharge state of the second compressor, respectively. The heat pump water heater according to claim 1.

The heat pump according to any one of claims 1 to 3, further comprising: load determination means for determining a required load; and start control means for selectively starting the first compressor and the second compressor based on the load determination means. Water heater.

The heat pump according to any one of claims 1 to 4, further comprising: load determination means for determining an instantaneous load; and switching control means for controlling start / stop of the first compressor and the second compressor based on the load determination means. Water heater.

Load determining means, comprising: a feedwater temperature detecting means for detecting a temperature of feedwater flowing through a feedwater pipe; a temperature setting means for setting a temperature of hot water supplied to a hot water supply terminal; and a flow rate detecting means for measuring a flow rate of water flowing through a water flow path. 6. The heat pump water heater according to claim 4, wherein at least one of said temperature detecting means, temperature setting means and flow rate detecting means is used.

The heat pump hot water supply apparatus according to any one of claims 1 to 6, wherein the smaller capacity of the first compressor and the second compressor is always operated in the full load range.

The heat pump water heater according to any one of claims 1 to 7, further comprising first compressor control means for controlling the number of revolutions of the first compressor.

The heat pump hot water supply apparatus according to any one of claims 1 to 8, further comprising a second compressor control unit that controls a rotation speed of the second compressor.

The heat pump water heater according to any one of claims 1 to 9, wherein the maximum output of the first compressor is equal to or larger than the minimum output of the second compressor.

The heat pump water heater according to any one of claims 1 to 10, further comprising a refrigerant backflow prevention unit for the compressor.

The heat pump hot water supply apparatus according to any one of claims 1 to 11, further comprising a leveling means for leveling an amount of lubricating oil in the compressor.

The first compressor and the second compressor are housed in the same adiabatic space, and the operating compressor warms up the stopped compressor, according to any one of claims 1 to 12. Heat pump water heater.

The refrigerant circulation circuit is a supercritical heat pump cycle in which the pressure of the refrigerant is equal to or higher than the critical pressure, and heats the flowing water in the water flow path of the heat exchanger with the refrigerant pressurized to the critical pressure or higher. 2. The heat pump water heater according to claim 1.