JP4104261B2

JP4104261B2 - Water heater

Info

Publication number: JP4104261B2
Application number: JP33975099A
Authority: JP
Inventors: 誠治三輪; 久介榊原; 忠幸百瀬; 正彦伊藤; 健一藤原; 智明小早川; 和俊草刈; 路之斉川
Original assignee: Central Research Institute of Electric Power Industry; Tokyo Electric Power Co Inc; Denso Corp
Current assignee: Central Research Institute of Electric Power Industry; Tokyo Electric Power Co Inc; Denso Corp
Priority date: 1999-11-30
Filing date: 1999-11-30
Publication date: 2008-06-18
Anticipated expiration: 2019-11-30
Also published as: JP2001153458A

Description

【０００１】
【発明の属する技術分野】
本発明は、蓄熱式の給湯装置に関する。
【０００２】
【従来の技術】
従来技術として、例えば特開平５−９９５０７号公報に開示された蓄熱式給湯装置がある。この給湯装置は、図１３に示すように、蓄熱用流体を貯留するタンク１００と、このタンク１００の外部に設けられた熱交換器１１０を備え、タンク１００内の蓄熱用流体をヒータ１２０で加熱し、その加熱された蓄熱用流体をポンプ１３０で熱交換器１１０に循環させ、蓄熱用流体に蓄熱された熱エネルギーで熱交換器１１０を流通する給湯用水を加熱するものである。
【０００３】
【発明が解決しようとする課題】
ところが、上記の給湯装置では、熱交換器１１０で放熱した蓄熱用流体の温度と熱交換器１１０で加熱される前の給湯用水（未加熱の給湯用水）の温度との温度差ΔＴが大きくなる。この温度差ΔＴに相当する熱量は、熱交換に使われることなく捨てられる熱量であるため、効率の悪い給湯システムであった。
本発明は、上記事情に基づいて成されたもので、その目的は、熱交換能力に優れ、且つ効率の良い給湯装置を提供することにある。
【０００４】
【課題を解決するための手段】
（請求項１の手段）
蓄熱用流体が流通する第１の配管と給湯用水が流通する第２の配管とを隣接して設け、且つ蓄熱用流体と給湯用水とが対向流となるように構成され、両者間で熱交換を行う対向流式熱交換器と、第２の配管と接続され、給湯用水を端末へと導く給湯管と、タンクの上部から加熱された蓄熱用流体を取り出し、第１の配管を通過させた後、タンクの下部に戻すための循環通路と、この循環通路に蓄熱用流体を循環させるポンプ手段と、循環通路を介して第１の配管を流通する蓄熱用流体の流量を制御する流量制御手段とを備えている。
この構成では、対向流式熱交換器を使用し、且つ第１の配管を流れる蓄熱用流体の流量を制御することにより、第１の配管を通過した後の蓄熱用流体の温度を加熱前の給湯用水の温度近傍まで低減できる。これにより、蓄熱用流体と給湯用水との熱交換時における熱ロスを極力小さくすることが可能となり、効率の良い給湯システムを実現できる。
【０００５】
また、タンク内の下部から蓄熱用流体を取り出して加熱手段へ供給し、加熱手段で加熱された蓄熱用流体をタンク内の上部へ戻す流体加熱用通路を備えている。
タンク内の上部から蓄熱用流体を取り出して対向流式熱交換器の第１の配管へ流し、熱交換後の蓄熱用流体をタンク内の下部へ戻しているため、給湯用水との熱交換によって温度低下した蓄熱用流体をタンク内の下部から取り出して加熱手段で加熱し、タンク内の上部へ戻すことで効率的に蓄熱用流体に蓄熱することができる。
また、流量制御手段は、第２の配管に流入する給湯用水の温度を検出する第１の温度検出手段と、第２の配管を通過する給湯用水の流量を検出する流量検出手段とを備え、前記給湯管から出湯される給湯用水の目標温度、第１の温度検出手段によって検出される給湯用水の温度、及び流量検出手段によって検出される給湯用水の流量に基づいて、熱交換後の蓄熱用流体の温度と第２の配管に流入する給湯用水の温度との温度差が所定範囲となるように、第１の配管を流通する蓄熱用流体の流量を調節する。
この構成では、給湯用水の温度及び流量に応じて第１の配管を流通する蓄熱用流体の流量を調節することにより、給湯用水を目標温度まで加熱するために必要十分な流量の蓄熱用流体を第１の配管に流通させることができる。その結果、蓄熱用流体が第１の配管から流出するときには、この蓄熱用流体の温度を加熱前の給湯用水の温度近傍まで確実に低下させることができる。
そして、第１の配管を流通する前記蓄熱用流体と熱交換し、第２の配管から流出した給湯用水と未加熱の給湯用水とを混合する混合手段を備え、目標温度は、実際に給湯される温度よりも所定温度高い温度に設定され、この目標温度まで加熱された給湯用水を混合手段によって未加熱の給湯用水と混合することにより、給湯用水の温度を給湯すべき温度まで低下させる。流量制御手段の流量制御によって、直接、給湯用水の温度を調節すると、温度変化の応答性が遅いため、温度制御の精度が低下する場合がある。しかし、本手段に記載したように、混合手段を用いると、給湯用水の温度を実際に給湯される温度に精度よく調節できる。
【０００６】
（請求項２の手段）
加熱手段は、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、臨界圧力以上に昇圧された冷媒により蓄熱用流体を加熱する。
超臨界ヒートポンプサイクルにおいては、蓄熱用流体を目標温度（例えば６５〜９０度）まで加熱する場合、加熱前の給湯用水の温度が低いほど、高圧圧力が低くなることでサイクル効率（ＣＯＰ＝加熱能力／消費電力）が向上する。従って、加熱前の給湯用水の温度近傍まで低減された蓄熱用流体を超臨界ヒートポンプサイクルにて加熱することにより、サイクル効率が向上し、省動力運転を行うことができる。
【０００８】
（請求項３の手段）
流量制御手段は、第２の配管から流出する給湯用水の温度を検出する第２の温度検出手段を備え、この第２の温度検出手段によって検出される給湯用水の温度が目標温度となるように、第１の配管を流通する蓄熱用流体の流量を補正する。
これにより、給湯用水の温度を目標温度に精度良く調節することができる。
【００１０】
（請求項４の手段）
目標温度は、通常使用される給湯水温度よりも高い一定温度に設定される。実際の設定給湯温度に関わらず、目標温度を一定温度にすることにより、混合手段による冷温水混合を精度良く行うことができる。
【００１１】
（請求項５の手段）
熱交換器がタンク内に配置されている。
この構成によれば、加熱された蓄熱用流体と給湯用水とをタンクの内部で熱交換できるので、放熱による熱損失が少なく、給湯能力を向上できる。
さらに、熱交換器で加熱された湯に熱交換器で加熱される前の水を混合して給湯用水の温度調節を行う給湯温度調節手段を具備している。この場合、循環通路を流れる流体流量を変更する必要がなく、流体流量を一定に保つことができるので、熱交換器で加熱された湯の温度変動を小さくできる。これにより、設定温度に対して給湯用水の温度制御を精度良く行うことができる。
【００１２】
（請求項６の手段）
循環通路及びポンプ手段は、タンク内に設けられている。この場合、加熱された蓄熱用流体がタンクの外部へ取り出されることがないため、熱交換器だけをタンク内に配置した場合より更に熱損失を少なくできる。
【００１３】
（請求項７の手段）
タンク内に貯留されている蓄熱用流体の温度がタンク内の上下方向で異なる場合（例えばタンク内の上部側では流体温度が高く、下部側では流体温度が低くなっている場合）は、熱交換器を断熱材で覆うことにより、熱交換器を流れる高温流体の熱がタンク内の低温流体へ放出されることを防止できる。
【００１４】
（請求項８の手段）
ポンプ手段は、給湯用配管を流れる給湯用水のエネルギーを受けて回転する第１の羽根車と、循環通路に設けられ、第１の羽根車の回転が伝達されて回転する第２の羽根車とを備え、この第２の羽根車の回転によって循環通路に蓄熱用流体を循環させることを特徴とする。この構成によれば、給水圧のエネルギーだけで潤滑通路に蓄熱用流体を流すことができるので、ポンプ手段として一般的な電動ポンプを用いた場合の駆動電力が不要となる。
【００１５】
（請求項９の手段）
大気開放型のタンクを使用することにより、有圧タンクのような耐圧設計が不要となるため、タンク自体を樹脂によって成形することができる。この場合、通常タンク材料として用いられるステンレス鋼加工に必要なプレス工程や溶接工程が不要となり、従来より製作コストを低く抑えることができる。
また、有圧タンクを使用する構成に必要となる減圧弁、圧力逃がし弁、負圧作動弁、缶体保護弁等の部品が不要となる。更に、有圧タンクのように、耐圧上から円筒形状とする必要がなく、タンク形状の設計自由度を高くできる。
【００１８】
（請求項１０の手段）
請求項５に記載した給湯温度調節手段は、給湯用配管の熱交換器下流に設けられた混合弁と、熱交換器の上流で給湯用配管から分岐して混合弁に接続された分岐配管と、混合弁より下流の給湯用水温度を検出する水温センサとを有し、この水温センサの検出温度に基づいて混合弁での湯と水との混合割合を調節することができる。この構成によれば、混合弁で湯と水との混合割合を調節することで給湯用水の温度を制御できるので、設定温度に対する温度制御が容易である。
【００１９】
【発明の実施の形態】
次に、本発明の実施例を図面に基づいて説明する。
（第１実施例）
図１は給湯装置の構成を示す模式図である。
本実施例の給湯装置１は、一般家庭用として使用されるもので、蓄熱用流体Ｗを貯留するタンク２、このタンク２内の蓄熱用流体Ｗを加熱する加熱手段（後述する）、タンク２内の蓄熱用流体Ｗを汲み上げる電動ポンプ３、この電動ポンプ３により汲み上げられた蓄熱用流体Ｗと給湯用配管（給水管４と給湯管５）に給水された給湯用水とを熱交換させる給湯用熱交換器６、及び本給湯システムの作動を制御する制御装置（ポンプ制御部７とサイクル制御部８）等より構成されている。
【００２０】
ａ）タンク２は、空気孔２ａを通じて大気に開放され、タンク２内部が大気圧に保たれている。このタンク２は、例えば樹脂材料で形成され、直方体形状に設けられている。また、タンク２内の蓄熱用流体Ｗに蓄えられた熱がタンク２の壁面より大気中へ放出されることを低減するために、タンク２の外周をグラスウールやウレタン等の断熱材で覆っても良い。
蓄熱用流体Ｗは、主成分が水であり、防腐剤、凍結防止剤、ＬＬＣ等が必要に応じて添加されている。
【００２１】
ｂ）加熱手段は、例えば炭酸ガスを冷媒として使用することにより、高圧側の冷媒圧力が冷媒の臨界圧力以上となる超臨界ヒートポンプサイクルＣを使用している。
このヒートポンプサイクルＣは、圧縮機９、蓄熱用熱交換器１０、膨張弁１１、蒸発器１２、アキュムレータ１３等の機能部品より構成されている。
圧縮機９は、内蔵する電動モータ（図示しない）によって駆動され、アキュムレータ１３より吸引した気相冷媒を臨界圧力以上まで圧縮して吐出する。
【００２２】
蓄熱用熱交換器１０は、冷媒と蓄熱用流体Ｗとを熱交換するもので、例えば冷媒が流れる冷媒通路１０ａと蓄熱用流体Ｗが流れる蓄熱用流体通路１０ｂとが二重管構造に設けられ、且つ冷媒の流れ方向と蓄熱用流体Ｗの流れ方向とが対向するように構成された対向流式の蓄熱用熱交換器１０である。
膨張弁１１は、蓄熱用熱交換器１０から流出する冷媒を減圧して蒸発器１２に供給する。
蒸発器１２は、膨張弁１１で減圧された冷媒を大気との熱交換によって蒸発させる。
アキュムレータ１３は、蒸発器１２より流出する冷媒を気液分離して、気相冷媒のみ圧縮機９に吸引させるとともに、サイクル中の余剰冷媒を蓄えている。
【００２３】
蓄熱用熱交換器１０の蓄熱用流体通路１０ｂは、流入管１４と流出管１５を介してタンク２に接続され、流入管１４に設けられた電動ポンプ１６が作動することでタンク２内の蓄熱用流体Ｗが循環する。但し、流入管１４の上流端はタンク２内の底部に開口し、流出管１５の下流端はタンク２内の上部に開口している。これにより、蓄熱用熱交換器１０で冷媒との熱交換により加熱された蓄熱用流体Ｗが流出管１５を通じてタンク２内の上部へ送り込まれるため、タンク２内の上部側から下部側へ向かって順次蓄熱用流体Ｗに蓄熱されていく。なお、タンク２内の蓄熱用流体Ｗは、家庭の給湯使用量に応じた蓄熱量を確保できれば良いため、必ずしもタンク２内の蓄熱用流体全体が高温に維持されている必要はない。
【００２４】
従って、給湯使用量が少ない家庭では、例えばタンク２内の半分程度の蓄熱用流体Ｗに蓄熱されていれば良い。この場合、タンク２内では、図１に示すように、蓄熱用流体Ｗの温度による比重差によって、タンク２内の上部側から下部側へ向かって温度の高い蓄熱用流体Ｗ１、中間温度の蓄熱用流体Ｗ２、温度の低い蓄熱用流体Ｗ３に自然に分離され、中間温度の蓄熱用流体Ｗ２は、温度の高い蓄熱用流体Ｗ１と温度の低い蓄熱用流体Ｗ３との間を断熱する役割も果たしており、その厚みは蓄熱用流体全体に比べれば僅かである。
【００２５】
ｃ）電動ポンプ３は、例えばタンク２の上部に設置されて、吸入管１７を介してタンク２に接続され、吐出管１８を介して給湯用熱交換器６に接続されている。なお、吸入管１７は、その上流端（吸込口）がタンク２内の上部（温度の高い蓄熱用流体Ｗ１）に開口している。従って、電動ポンプ３が作動すると、温度の高い蓄熱用流体Ｗ１を汲み上げて給湯用熱交換器６へ圧送することができる。
【００２６】
ｄ）給湯用熱交換器６は、電動ポンプ３によって汲み上げられた蓄熱用流体Ｗが流れる一次側通路６ａと、給湯用配管（給水管４と給湯管５）に接続された二次側通路６ｂとを有し、例えば図２に示すように、一次側通路６ａを形成する外側管６Ａの内部に二次側通路６ｂを形成する内側管６Ｂが挿通する二重管構造である。
ここで、外側管６Ａは、熱ロスを低く抑えるために樹脂材を使用し、内側管６Ｂは熱伝導率の高い銅材を使用することが望ましい。また、内側管６Ｂは、外側管６Ａと同様に円筒管でも良いが、例えば図２に示すように、その壁面に径方向の凹凸形状を設けても良い。この場合、一次側通路６ａと二次側通路６ｂとの伝熱面積が増加して、蓄熱用流体Ｗと給湯用水との熱交換効率を向上できる。
【００２７】
この給湯用熱交換器６は、図１に示すように、タンク２の内部で上下方向に配置されて、一次側通路６ａの上端が吐出管１８を介して電動ポンプ３に接続され、一次側通路６ａの下端（流出口）がタンク２内の底部に開口している。また、二次側通路６ｂは、その下端がタンク２内の低部で給水管４に接続され、上端がタンク２の上部へ突出して給湯管５に接続されている。従って、給湯用熱交換器６は、図１に矢印で示すように、一次側通路６ａを上から下へ向かって流れる蓄熱用流体Ｗの流れ方向と二次側通路６ｂを下から上へ向かって流れる給湯用水の流れ方向とが対向する対向流式として構成されている。なお、給水管４と給湯管５は、給湯用配管の一部である。
【００２８】
ｅ）制御装置は、電動ポンプ３の作動を制御するポンプ制御部７を有し、このポンプ制御部７に「水流」の有無を検出する給湯水検出センサ１９及び給湯用水の温度を検出する水温センサ２０の検出信号が入力され、給湯水検出センサ１９の検出結果に基づいて電動ポンプ３のＯＮ／ＯＦＦ制御を行い、水温センサ２０の検出結果に基づいて電動ポンプ３の回転数制御を行う。なお、給湯水検出センサ１９は、給水管４または給湯管５に設けられ、水温センサ２０は、給湯管５に設けられている。
【００２９】
また、制御装置は、ヒートポンプサイクルＣの圧縮機９に内蔵されている電動モータ、及び流入管１４に設けられている電動ポンプ１６を制御するサイクル制御部８を有している。このサイクル制御部８は、蓄熱用熱交換器１０で加熱された蓄熱用流体Ｗの温度を一定温度に保つために、加熱後の蓄熱用流体温度を検出する蓄熱温度センサ２１の検出温度に基づいて電動ポンプ１６の回転数制御を行っている。
【００３０】
次に、本実施例の作動を説明する。
タンク２内の蓄熱用流体Ｗは、例えば深夜電力を利用してヒートポンプサイクルＣと電動ポンプ１６を作動させることにより、必要量だけ加熱されて蓄熱される。その後、使用者が給湯栓（図示しない）を開いて給湯用配管（給湯管５）に水流が生じると、給湯水検出センサ１９によって「水流」が検出され、ポンプ制御部７より出力される制御信号（ＯＮ信号）を受けて電動ポンプ３が起動する。この電動ポンプ３が作動すると、タンク２内の上部から高温の蓄熱用流体Ｗが汲み上げられ、給湯用熱交換器６の一次側通路６ａに蓄熱用流体Ｗの流れが生じる。これにより、給湯用熱交換器６の二次側通路６ｂを流れる給湯用水が蓄熱用流体Ｗの熱エネルギーを受けて加熱される。
【００３１】
ここで、ポンプ制御部７は、水温センサ２０によって検出される湯の温度が所望の給湯温度（使用者によって設定される給湯温度）になるように電動ポンプ３の駆動状態（回転数）を制御する。即ち、水温センサ２０によって検出される湯の温度が所望の給湯温度より低い時は、電動ポンプ３の回転数を大きくして一次側通路６ａを流れる蓄熱用流体Ｗの循環量を増加させる。これにより、一次側通路６ａを流れる蓄熱用流体Ｗと二次側通路６ｂを流れる給湯用水との熱交換量が増加するため、湯の温度が上昇する。また、水温センサ２０によって検出される湯の温度が所望の給湯温度より高い時は、電動ポンプ３の回転数を小さくして一次側通路６ａを流れる蓄熱用流体Ｗの循環量を減少させる。これにより、一次側通路６ａを流れる蓄熱用流体Ｗと二次側通路６ｂを流れる給湯用水との熱交換量が減少するため、湯の温度が低下する。
【００３２】
（第１実施例の効果）
本実施例の給湯装置１は、給湯用熱交換器６をタンク２内に配置しているので、蓄熱用流体Ｗと給湯用水との熱交換をタンク２の内部で行うことができる。この結果、大気への放熱による熱損失が少なくなるため、その分、給湯能力を向上できる。また、給湯用熱交換器６をタンク２の外部に配置した場合と比較して省スペースが可能となる。
【００３３】
本実施例では、大気開放型のタンク２を使用しているので、有圧タンク（密閉型タンク）のような耐圧設計が不要となるため、タンク２を樹脂によって成形することができる。この場合、通常タンク材料として用いられるステンレス鋼加工に必要なプレス工程や溶接工程が不要となり、従来より製作コストを低く抑えることができる。また、有圧タンクを使用する構成に必要となる減圧弁、圧力逃がし弁、負圧作動弁、缶体保護弁等の部品が不要となる。更に、有圧タンクのように、耐圧上から円筒形状とする必要がなく、タンク形状の設計自由度を高くできる効果がある。
【００３４】
給湯用熱交換器６の内側管６Ｂを凹凸形状とすることにより、蓄熱用流体Ｗが流れる一次側通路６ａと給湯用水が流れる二次側通路６ｂとの熱交換面積を大きく取ることができる。このため、内側管６Ｂを丸管で構成した場合より熱交換能力が向上し、給湯用熱交換器６の全長を短くすることが可能である。
蓄熱用流体Ｗの加熱手段としてヒートポンプサイクルＣを用いているので、ガス式や灯油式の加熱手段と比較してランニングコスト（主に電気代）が格段に安価である。
なお、加熱された蓄熱用流体Ｗは、給湯用だけでなく、床暖房用、室内空調用としても使用できる。また、蓄熱用流体Ｗを風呂のお湯として使用することもできる。この場合、蓄熱用流体Ｗを熱ロス無しで使用できるので、全体の蓄熱量を有効に活用することができる。
【００３５】
（第２実施例）
本実施例は、給湯用熱交換器６に蓄熱用流体Ｗを循環させる手段としてタービンを用いた一例である。
タービンは、図３に示すように、給湯用水の流れを受けて回転する第１の羽根車２２と、この第１の羽根車２２の回転が伝達されて回転する第２の羽根車２３より構成される。
【００３６】
第１の羽根車２２は、給湯管５に設けられた収納室２４に収納され、給湯管５に水流が生じると、その流量に応じた回転数で回転することができる。
第２の羽根車２３は、吸入管１７と吐出管１８との間に設けられた収納室２５に収納され、自身の回転により汲み上げた蓄熱用流体Ｗを一次側通路６ａへ圧送することができる。
第１の羽根車２２と第２の羽根車２３は、それぞれに埋設された磁石（図示しない）の吸引力によって連動することができる。この構成では、第１の羽根車２２と第２の羽根車２３とをシャフト等によって連結する必要がないので、収納室２４と収納室２５とを完全に隔離することができ、給湯用水と蓄熱用流体Ｗとが混合することは起こり得ない。
【００３７】
本実施例の構成によれば、給湯管５に生じる水流のエネルギーだけで蓄熱用流体Ｗを一次側通路６ａに循環させることができるので、第１実施例に示した電動ポンプ３を使用する必要がなく、電動ポンプ３を駆動するための電力が不要となる。
また、予め給湯用水流量と各羽根車２２、２３の回転数と一次側通路６ａを流れる蓄熱用流体Ｗの流量とが目的の給湯温度となるように配管圧損を付ける設計をすれば、第１実施例に示した給湯水検出センサ１９、水温センサ２０、及びポンプ制御部７が不要となるため、安価なシステムを提供できる。
【００３８】
（第３実施例）
本実施例は、図４に示すように、一次側通路６ａを流れる蓄熱用流体Ｗの流量を電動式流量制御弁２６によって制御する一例である。
電動式流量制御弁２６は、電動ポンプ３の前後どちらかに設置され、ポンプ制御部７からの指令を受けて蓄熱用流体流量を可変する。
この構成によれば、電動式流量制御弁２６によって蓄熱用流体流量を可変するので、電動ポンプ３の回転数を一定にできる。第１実施例のように電動ポンプ３の回転数を変更する場合は、交流であればインバータ等の速度可変回路が必要であるが、電動ポンプ３の回転数を一定にすることで速度可変回路が不要となる。
なお、本実施例の構成（電動式流量制御弁２６）は、第２実施例に示したタービンを使用するシステムにも適用できる。
【００３９】
（第４実施例）
本実施例は、図５に示すように、一次側通路６ａを流れる蓄熱用流体Ｗの流量を温度検知式流量制御弁２７によって制御する一例である。
温度検知式流量制御弁２７は、不活性ガスが封入されたガス封入部２７ａを有し、このガス封入部２７ａの内部圧力に応じて弁開度を可変する構造であり、そのガス封入部２７ａは、給湯用熱交換器６で加熱された給湯用水の温度を感知できる位置に設置されている。
この温度検知式流量制御弁２７は、例えば給湯温度が低くなると、ガス封入部２７ａの内部圧力が低下することで弁開度が大きくなり、蓄熱用流体流量を増やして給湯温度を上げようとする。また、給湯温度が高くなると、ガス封入部２７ａの内部圧力が上昇することで弁開度が小さくなり、蓄熱用流体流量を減らして給湯温度を下げようとする。
【００４０】
本実施例の構成によれば、温度検知式流量制御弁２７が機械的に給湯温度を所望の設定温度に維持しようと働くため、第３実施例の場合と同様に、電動ポンプ３の回転数を一定にでき、インバータ等の速度可変回路が不要となる。
また、温度検知式流量制御弁２７は、ガス封入部２７ａの内部圧力に応じて弁開度を可変する構造であるため、給湯用水の温度を検出する水温センサ２０が不要である。
なお、本実施例の構成（温度検知式流量制御弁２７）は、第２実施例に示したタービンを使用するシステムにも適用できる。
【００４１】
（第５実施例）
本実施例は、給湯用熱交換器６で加熱された湯に給湯用熱交換器６で加熱される前の水を混合して給湯用水の温度調節を行う一例である。具体的には、図６に示すように、給水管４に分岐接続された分岐配管２８を有し、この分岐配管２８の下流端を給湯管５に設けられた混合弁２９に接続して構成される。
混合弁２９は、分岐配管２８より流入する水の量を可変し、水温センサ２０で検出される給湯用水の温度が設定された給湯温度になるように、ポンプ制御部７からの指令を受けて水量を調節している。
【００４２】
この構成によれば、混合弁２９によって給湯用水の温度を調節できるので、給湯用熱交換器６で加熱された湯に多少の温度変動があっても、設定温度に対して給湯用水の温度制御をより精度良く行うことができる。
なお、本実施例の構成は、第２実施例に示したタービンを使用するシステムにも適用できる。
【００４３】
（第６実施例）
本実施例は、図７に示すように、加熱手段であるヒートポンプサイクルＣの蓄熱用熱交換器１０をタンク２内に配置した一例である。また、蓄熱用熱交換器１０の移動に伴って、電動ポンプ１６を流出管１５に設けている。この電動ポンプ１６は、第１実施例と同様に、蓄熱温度センサ２１で検出される蓄熱用流体温度が一定となるように、サイクル制御部８によって回転数制御される。
【００４４】
この構成によれば、蓄熱用熱交換器１０をタンク２内に配置するため、タンク２の外部に構成されるヒートポンプサイクルＣの必要体積を減らしてコンパクトにできる。また、蓄熱用熱交換器１０から大気中への熱ロスが無くなるため、蓄熱能力が向上する。
本実施例の構成は、第２実施例に示したタービンを使用するシステムにも適用できる。
【００４５】
（第７実施例）
本実施例は、図８に示すように、給湯用熱交換器６に蓄熱用流体Ｗを循環させるポンプ機能と、蓄熱用熱交換器１０に蓄熱用流体Ｗを循環させるポンプ機能を１つの電動ポンプ３０で行う一例である。なお、ヒートポンプサイクルＣは、第６実施例と同様に、蓄熱用熱交換器１０をタンク２内に配置した構成である。
この場合、１つの電動ポンプ３０で蓄熱動作と給湯動作を行うため、蓄熱動作を行う場合と給湯動作を行う場合とで、蓄熱用流体Ｗの循環通路を切り替える必要が生じる。そこで、図８に示すように、電動ポンプ３０の前後にそれぞれ三方弁３１、３２を配置し、制御装置５０（ポンプ制御部、サイクル制御部）の指令によって各三方弁３１、３２の通路方向を切り替えている。
【００４６】
ここで、各三方弁３１、３２の通路方向を切り替えた場合の蓄熱用流体Ｗの流れを説明する。
ａ）蓄熱時
タンク２内下部（低温蓄熱用流体Ｗ３）→蓄熱用熱交換器１０の蓄熱用流体通路１０ｂ→第１流出管１５ａ→三方弁３１→共通配管３３→電動ポンプ３０→共通配管３４→三方弁３２→第２流出管１５ｂ→タンク２内上部（高温蓄熱用流体Ｗ１）へと蓄熱用流体Ｗが流れる。
【００４７】
ｂ）給湯時
タンク２内上部（高温蓄熱用流体Ｗ１）→吸入管１７→三方弁３１→共通配管３３→電動ポンプ３０→共通配管３４→三方弁３２→吐出管１８→給湯用熱交換器６の一次側通路６ａ→タンク２内下部（低温蓄熱用流体Ｗ３）へと蓄熱用流体Ｗが流れる。
本実施例の構成によれば、蓄熱動作と給湯動作を１つの電動ポンプ３０で行うことができるため、電動ポンプを２個使用する場合と比較してコストダウンを図ることができる。
【００４８】
（第８実施例）
本実施例は、第７実施例と同様に、給湯用熱交換器６に蓄熱用流体Ｗを循環させるポンプ機能と、蓄熱用熱交換器１０に蓄熱用流体Ｗを循環させるポンプ機能を１つの電動ポンプ３０で行うもので、図９に示すように、ヒートポンプサイクルＣの蓄熱用熱交換器１０をタンク２の外部に配置した構成（第１実施例と同じ）である。この場合も、第７実施例と同じ作用及び効果を得ることができる。
【００４９】
（第９実施例）
本実施例は、図１０に示すように、電動ポンプ３をタンク２内に配置した一例である。この場合、加熱された蓄熱用流体Ｗがタンク２の外部へ取り出されることがないため、給湯用熱交換器６だけをタンク２内に配置した場合より更に熱損失を少なくできる効果がある。
なお、本実施例では、給湯用熱交換器６の一次側通路６ａに蓄熱用流体Ｗを循環させる手段として電動ポンプ３を使用しているが、第２実施例で説明したタービンを使用する場合でも、同様にタービン（第１の羽根車２２と第２の羽根車２３）をタンク２内に配置しても良い。
【００５０】
（第１０実施例）
本実施例は、図１１に示すように、給湯用熱交換器６をタンク２の外部に配置した給湯システムの一例である。
本実施例の給湯装置１は、蓄熱用流体Ｗを貯留するタンク２、蓄熱用流体Ｗを加熱する加熱手段（後述する）、タンク２内の蓄熱用流体Ｗを汲み上げる電動ポンプ３、この電動ポンプ３により汲み上げられた蓄熱用流体Ｗと給湯用水とを熱交換させる給湯用熱交換器６、給湯用熱交換器６で加熱された給湯用水と加熱される前の給湯用水とを混合させる混合弁２９、及び給湯装置１の作動を制御する制御装置（下述する）等より構成される。
【００５１】
タンク２は、空気孔２ａを通じて大気に開放され、タンク２の内部が大気圧に保たれている。
加熱手段は、第１実施例と同じく、例えば炭酸ガスを冷媒として使用する超臨界ヒートポンプサイクルＣであり、第１実施例と同様に、流入管１４と流出管１５を介してタンク２に接続されている。なお、本発明の流体加熱用通路は、タンク２内の底部から電動ポンプ１６の作動によって蓄熱用流体ＷをヒートポンプサイクルＣに供給する流入管１４と、ヒートポンプサイクルＣで加熱された蓄熱用流体Ｗをタンク２内の上部に戻す流出管１５とで構成される。
【００５２】
電動ポンプ３は、吸入管１７を通じてタンク２内の上部から蓄熱用流体Ｗを汲み上げて、給湯用熱交換器６へ圧送し、給湯用熱交換器６で給湯用水と熱交換された蓄熱用流体Ｗをタンク２内の下部へ戻している。なお、本実施例では電動ポンプ３を給湯用熱交換器６の上流側（圧送する側）に設置しているが、給湯用熱交換器６の下流側（吸込み側）に設置しても良い。
【００５３】
給湯用熱交換器６は、図２に示したように、外側管６Ａ（第１の配管）と内側管６Ｂ（第２の配管）から成る二重管構造に設けられ、内側管６Ｂと外側管６Ａの間に形成される環状の一次側通路６ａを蓄熱用流体Ｗが流通し、内側管６Ｂの内部に形成される二次側通路６ｂを給湯用水が流通する。但し、一次側通路６ａを流れる蓄熱用流体Ｗの流れ方向と二次側通路６ｂを流れる給湯用水の流れ方向とが互いに反対方向となる対向流式として構成されている。
給湯用水が流通する給湯用配管は、第５実施例と同様に、給湯管５に混合弁２９が設けられ、この混合弁２９に給水管４から分岐接続された分岐配管２８の下流端が接続されている。
【００５４】
制御装置は、電動ポンプ３の作動を制御するポンプ制御部７と、ヒートポンプサイクルＣの作動を制御するサイクル制御部８を有している。
ポンプ制御部７では、給水管４に設けられた第１の温度センサ５１と流量センサ５４、給湯管５に設けられた第２の温度センサ５２と第３の温度センサ５３よりそれぞれ信号を入力し、これらの信号を基に、予めインプットされたプログラムに沿って所定の演算を行い、その演算結果に従って電動ポンプ３の回転数を制御している。
【００５５】
なお、第１の温度センサ５１は、給水管４に供給される給湯用水（未加熱の給湯用水）の温度Ｔ2iを検出し、第２の温度センサ５２は、給湯用熱交換器６を通って加熱された給湯用水の温度Ｔ2oを検出し、第３の温度センサ５３は、未加熱の給湯用水と加熱された給湯用水とを混合弁２９で混合して得られる給湯用水の温度Ｔ2 を検出する。また、流量センサ５４は、給水管４に供給される給湯用水の流量を検出する。
サイクル制御部８では、加熱後の蓄熱用流体Ｗの温度を検出する蓄熱温度センサ２１の検出温度に基づいて電動ポンプ１６の回転数制御を行っている。
【００５６】
次に、本システムの作動を説明する。
給湯装置１の設定温度は、３５〜５０℃（通常の使用温度）の範囲で１℃刻みに設定可能であり、給湯用熱交換器６から流出する給湯水温度は５０℃を目標温度とされる。なお、設定温度は５０℃以上にも設定可能であるが、その場合は、設定温度＋αの温度を目標温度とするか、もしくは設定温度そのものを目標温度とする。また、通常の使用温度において、目標温度を設定温度＋αの温度（変動値）とすることも可能である。
【００５７】
一定の給湯水温度を得るためには、第１の温度センサ５１で検出される給水温度、流量センサ５４で検出される給水流量、蓄熱温度センサ２１で検出される蓄熱用流体Ｗの温度をパラメータとする関係式から蓄熱用流体Ｗの流量を算出する。この場合、給水温度が低くなるほど、給水流量が増加するほど、また蓄熱用流体Ｗの温度が低くなるほど、蓄熱用流体Ｗの流量が増加するように、蓄熱用流体Ｗの流量が計算される。このようにして得られた流量の蓄熱用流体Ｗから給湯用水へ熱が十分に移動することにより、熱交換後の蓄熱用流体Ｗの温度Ｔ1oを給湯用水の温度Ｔ2i近傍まで低下させることが可能である（例えば温度差ΔＴが５℃以内）。
もちろん、前提として、給湯用熱交換器６は、蓄熱用流体Ｗから給湯用水へ熱を十分に移動させることができるだけの熱交換能力を有する必要があり、そのために、蓄熱用流体Ｗの流れ方向と給湯用水の流れ方向とが対向する対向流式熱交換器として構成されている。
【００５８】
上記の制御は、ある流量及び温度を有する給湯用水を目標温度まで加熱するための必要な蓄熱用流体Ｗの流量及び温度を考慮して求めるものであり、所謂フィードフォワード制御である。
このため、実際に演算した蓄熱用流体Ｗの流量では、目標温度に対して給湯用水の加熱温度が高過ぎたり、低過ぎたりする場合が生じる。このため、第２の温度センサ５２によって実際に加熱された給湯用水の温度Ｔ2oを検出し、その温度が目標温度となるように、蓄熱用流体Ｗの流量を補正しても良い。
【００５９】
また、目標温度を通常使用される給湯水温度より所定温度高い温度に設定することにより、給湯用水の温度を実際の給湯温度に精度良く調節することができる。即ち、ポンプ制御部７（流量制御手段）の流量制御によって、直接、給湯用水の温度を調節すると、温度変化の応答性が遅いため、温度制御の精度が低下する場合がある。しかし、本実施例のように、混合弁２９を用いて給湯用熱交換器６で加熱された温水と加熱される前の冷水とを混合させると、給湯用水の温度を実際に給湯される温度に精度よく調節できる。この場合、実際に使用される給湯用水の温度Ｔ2 を第３の温度センサ５３で検出しながら、目標温度まで加熱された給湯用水と未加熱の給湯用水とを混合弁２９で混合することにより、給湯用水の温度を給湯すべき温度まで低下させることができる。
また、目標温度を通常使用される給湯水温度より高い一定温度にすることで、冷温水の混合を安定して精度良く行うことができる。
【００６０】
本給湯システムでは、蓄熱用流体Ｗの加熱手段として超臨界ヒートポンプサイクルＣを使用しているが、この超臨界ヒートポンプサイクルＣでは、蓄熱用流体Ｗの温度によって高圧圧力（圧縮機９の吐出圧力）が決まるため、蓄熱用流体Ｗの温度が低下するほど、高圧圧力が低下してサイクル効率の良い領域で運転することができる。従って、上述の流量制御によってタンク２内の下部に溜められる蓄熱用流体Ｗの温度を給湯用水の温度近傍まで低下させ、その蓄熱用流体Ｗをタンク２内の下部から導入してヒートポンプサイクルＣにより加熱し、タンク２内の上部に戻すことにより、ヒートポンプサイクルＣのサイクル効率が向上し、省動力運転を行うことが可能になる。
【００６１】
なお、給水温度は、第１の温度センサ５１によって直接給水管４の水温を検出しても良いし、水温に関連する他のパラメータから水温を推定することにより、間接的に求めても良い。例えば、外気温度と水温とは関連性があるため、外気温度から水温を推定しても良いし、一年間における平均水温の変化を記憶し、カレンダー機能を有するタイマにより給水温度と見做すべき水温を演算しても良い。
また、蓄熱用流体Ｗの温度は、ヒートポンプサイクルＣ側において、所定の目標温度となるように蓄熱用流体Ｗを加熱しているので、ヒートポンプサイクルＣ側から蓄熱用流体Ｗの温度を得ることが可能である。
【００６２】
蓄熱用流体Ｗの温度として、予め一年を通じて目標温度が設定されていれば、その設定目標温度を蓄熱用流体Ｗの温度として利用すれば良い。
流量センサ５４は、給水管４と分岐配管２８との分岐点の上流側、もしくは混合弁２９の下流側に設置して、全体の給湯流量を検出しても良い。この場合、温度センサ５１、５２、５３の値より、給湯用熱交換器６と分岐配管２８の流量を各々熱量計算により推定することができる。
【００６３】
（変形例）
各実施例に示すタンク２は、必ずしも樹脂材料を使用する必要はなく、金属材料で成形しても良い。また、タンク２の形状は、直方体形状でなくても、例えば円筒形状でも良い。
第１実施例で説明した給湯用熱交換器６は、一次側通路６ａの内側に二次側通路６ｂを設けているが、その逆に一次側通路６ａの外側に二次側通路６ｂを設けても良い。また、上述した内側管６Ｂ及び外側管６Ａに使用される材料は一例であり、例えば内側管６Ｂは熱伝導率の高いアルミニウムを使用することができ、外側管６Ａは金属製でも良い。更に、給湯用熱交換器６の外周面を断熱材３５で覆っても良い（図２参照）。
【００６４】
また、各実施例に示す給湯用熱交換器６は、内側管６Ｂと外側管６Ａから成る二重管構造に限定されるものではなく、例えば図１２に示すような多穴管構造でも良い。これは、複数の一次側通路６ａが形成された一次側プレート３６と、同様に複数の二次側通路６ｂが形成された二次側プレート３７とを接着剤等で貼り合わせて構成される。各プレート３６、３７は、熱伝導率の高い銅、アルミニウム等を使用することができ、貼り合わせた２枚のプレート３６、３７の周囲を断熱材３８で覆っても良い。
各実施例に示した電動ポンプ３及びタービンをタンク２内に配置しても良い。この場合、加熱された蓄熱用流体Ｗがタンク２の外部へ取り出されることがないため、給湯用熱交換器６だけをタンク２内に配置した場合より更に熱ロスを少なくできる。
【図面の簡単な説明】
【図１】給湯装置の構成を示す全体図である（第１実施例）。
【図２】給湯用熱交換器を構成する外側管と内側管の断面図である。
【図３】給湯装置の構成を示す全体図である（第２実施例）。
【図４】蓄熱用流体の流量制御機構を示す構成図である（第３実施例）。
【図５】蓄熱用流体の流量制御機構を示す構成図である（第４実施例）。
【図６】給湯装置の構成を示す全体図である（第５実施例）。
【図７】給湯装置の構成を示す全体図である（第６実施例）。
【図８】給湯装置の構成を示す全体図である（第７実施例）。
【図９】給湯装置の構成を示す全体図である（第８実施例）。
【図１０】給湯装置の構成を示す全体図である（第９実施例）。
【図１１】給湯装置の構成を示す全体図である（第１０実施例）。
【図１２】給湯用熱交換器の断面図である（変形例）。
【図１３】従来の給湯装置の断面図である。
【符号の説明】
１給湯装置
２タンク
３電動ポンプ（ポンプ手段）
４給水管（給湯用配管）
５給湯管（給湯用配管）
６給湯用熱交換器（対向流式熱交換器）
６Ａ外側管（第１の配管）
６Ｂ内側管（第２の配管）
７ポンプ制御部（流量制御手段）
１４流入管（流体加熱用通路）
１５流出管（流体加熱用通路）
１７吸入管（循環通路）
１８吐出管（循環通路）
２０水温センサ（給湯温度調節手段）
２２第１の羽根車（ポンプ手段）
２３第２の羽根車（ポンプ手段）
２６電動式流量制御弁（流量制御弁）
２７温度検知式流量制御弁（流量制御弁）
２８分岐配管（給湯温度調節手段）
２９混合弁（給湯温度調節手段）
３５断熱材
５１第１の温度センサ（第１の温度検出手段）
５２第２の温度センサ（第２の温度検出手段）
５４流量センサ（流量検出手段）
Ｃヒートポンプサイクル（加熱手段）
Ｗ蓄熱用流体[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat storage type hot water supply apparatus.
[0002]
[Prior art]
As a conventional technique, for example, there is a regenerative hot water supply apparatus disclosed in Japanese Patent Laid-Open No. 5-99507. As shown in FIG. 13, this hot water supply apparatus includes a tank 100 for storing heat storage fluid and a heat exchanger 110 provided outside the tank 100, and heat storage fluid in the tank 100 is heated by a heater 120. Then, the heated heat storage fluid is circulated to the heat exchanger 110 by the pump 130, and the hot water supply water flowing through the heat exchanger 110 is heated by the heat energy stored in the heat storage fluid.
[0003]
[Problems to be solved by the invention]
However, in the hot water supply apparatus described above, the temperature difference ΔT between the temperature of the heat storage fluid radiated by the heat exchanger 110 and the temperature of hot water before being heated by the heat exchanger 110 (unheated hot water) increases. . Since the amount of heat corresponding to this temperature difference ΔT is the amount of heat that is discarded without being used for heat exchange, it is an inefficient hot water supply system.
The present invention has been made based on the above circumstances, and an object of the present invention is to provide a hot water supply apparatus that is excellent in heat exchange capability and efficient.
[0004]
[Means for Solving the Problems]
(Means of Claim 1)
The first pipe through which the heat storage fluid flows and the second pipe through which the hot water supply water are provided are adjacent to each other, and the heat storage fluid and the hot water supply are configured to face each other, and heat exchange is performed between the two. A counter-flow heat exchanger that performs A hot water pipe connected to the second pipe and leading hot water to the terminal; A circulation passage for taking out the heat storage fluid heated from the upper portion of the tank and passing it through the first pipe, and then returning it to the lower portion of the tank; pump means for circulating the heat storage fluid in the circulation passage; and circulation passage And a flow rate control means for controlling the flow rate of the heat storage fluid flowing through the first pipe.
In this configuration, the temperature of the heat storage fluid after passing through the first pipe is adjusted by using a counter-flow heat exchanger and controlling the flow rate of the heat storage fluid flowing through the first pipe before heating. It can be reduced to near the temperature of hot water. As a result, it is possible to minimize heat loss during heat exchange between the heat storage fluid and the hot water supply water, thereby realizing an efficient hot water supply system.
[0005]
Also, a fluid heating passage is provided that takes out the heat storage fluid from the lower part in the tank and supplies it to the heating means, and returns the heat storage fluid heated by the heating means to the upper part in the tank.
The heat storage fluid is taken out from the upper part of the tank and flows to the first pipe of the counter flow heat exchanger, and the heat storage fluid after the heat exchange is returned to the lower part of the tank. The heat storage fluid whose temperature has been lowered is taken out from the lower part in the tank, heated by the heating means, and returned to the upper part in the tank, whereby heat can be efficiently stored in the heat storage fluid.
The flow rate control means includes first temperature detection means for detecting the temperature of the hot water for water flowing into the second pipe, and flow rate detection means for detecting the flow of the hot water for water passing through the second pipe, Based on the target temperature of hot water discharged from the hot water pipe, the temperature of hot water detected by the first temperature detection means, and the flow rate of hot water detected by the flow rate detection means, The temperature difference between the temperature of the heat storage fluid after heat exchange and the temperature of the hot water supply water flowing into the second pipe is within a predetermined range. The flow rate of the heat storage fluid flowing through the first pipe is adjusted.
In this configuration, by adjusting the flow rate of the heat storage fluid flowing through the first pipe in accordance with the temperature and flow rate of the hot water supply water, the heat storage fluid having a flow rate sufficient to heat the hot water supply water to the target temperature is obtained. It can be made to distribute | circulate to 1st piping. As a result, when the heat storage fluid flows out from the first pipe, the temperature of the heat storage fluid can be reliably lowered to the vicinity of the temperature of the hot water supply water before heating.
And 1st piping Heat mixing with the heat storage fluid flowing through the second pipe and mixing means for mixing hot water and unheated hot water flowing out from the second pipe, and the target temperature is a predetermined temperature higher than the temperature at which the hot water is actually supplied The hot water supply water set to a high temperature and heated to the target temperature is mixed with the unheated hot water supply water by the mixing means, thereby lowering the temperature of the hot water supply water to a temperature at which the hot water is to be supplied. If the temperature of the hot water supply water is directly adjusted by the flow rate control of the flow rate control means, the responsiveness of the temperature change is slow, so the accuracy of the temperature control may be reduced. However, as described in this means, when the mixing means is used, the temperature of the hot water supply water can be accurately adjusted to the temperature at which the hot water is actually supplied.
[0006]
( Claim 2 Means)
The heating means is a supercritical heat pump cycle in which the pressure of the refrigerant becomes equal to or higher than the critical pressure, and heats the heat storage fluid with the refrigerant whose pressure is increased to the critical pressure or higher.
In the supercritical heat pump cycle, when the heat storage fluid is heated to a target temperature (for example, 65 to 90 degrees), the lower the temperature of the hot water supply water before heating, the lower the high-pressure pressure, and thus the cycle efficiency (COP = heating capacity) / Power consumption) is improved. Therefore, by heating the heat storage fluid reduced to near the temperature of hot water before heating with a supercritical heat pump cycle, cycle efficiency is improved and power saving operation can be performed.
[0008]
(Claims 3 Means)
The flow rate control means includes second temperature detection means for detecting the temperature of the hot water for water flowing out from the second pipe, so that the temperature of the hot water for water detected by the second temperature detection means becomes the target temperature. The flow rate of the heat storage fluid flowing through the first pipe is corrected.
Thereby, the temperature of the hot water supply water can be accurately adjusted to the target temperature.
[0010]
(Claims 4 Means)
The target temperature is set to a constant temperature higher than the normally used hot water temperature. Regardless of the actual set hot water supply temperature, by making the target temperature constant, cold / hot water mixing by the mixing means can be performed with high accuracy.
[0011]
(Claims 5 Means)
heat An exchanger is located in the tank.
According to this configuration, since heat can be exchanged between the heated heat storage fluid and hot water supply water inside the tank, heat loss due to heat radiation is small, and hot water supply capability can be improved.
Furthermore, the hot water heated by the heat exchanger is mixed with the water before being heated by the heat exchanger, and hot water supply temperature adjusting means for adjusting the temperature of the hot water is provided. In this case, it is not necessary to change the flow rate of the fluid flowing through the circulation passage, and the fluid flow rate can be kept constant, so that the temperature fluctuation of the hot water heated by the heat exchanger can be reduced. Thereby, the temperature control of the hot water supply water can be accurately performed with respect to the set temperature.
[0012]
(Claims 6 Means)
The circulation passage and the pump means are provided in the tank. In this case, since the heated heat storage fluid is not taken out of the tank, heat loss can be further reduced as compared with the case where only the heat exchanger is arranged in the tank.
[0013]
(Claims 7 Means)
When the temperature of the heat storage fluid stored in the tank differs in the vertical direction in the tank (for example, when the fluid temperature is high on the upper side and the fluid temperature is low on the lower side), heat exchange is performed. By covering the vessel with a heat insulating material, it is possible to prevent the heat of the high-temperature fluid flowing through the heat exchanger from being released to the low-temperature fluid in the tank.
[0014]
(Claims 8 Means)
The pump means includes a first impeller that rotates in response to the energy of the hot water flowing through the hot water supply pipe, a second impeller that is provided in the circulation passage, and that rotates by transmitting the rotation of the first impeller. The heat storage fluid is circulated in the circulation passage by the rotation of the second impeller. According to this configuration, since the heat storage fluid can be caused to flow through the lubrication passage only by the energy of the supply water pressure, the driving power in the case where a general electric pump is used as the pump means becomes unnecessary.
[0015]
(Claims 9 Means)
By using a tank that is open to the atmosphere, a pressure-resistant design like a pressurized tank is not required, so that the tank itself can be molded from resin. In this case, a pressing process and a welding process necessary for processing stainless steel, which is usually used as a tank material, are unnecessary, and the manufacturing cost can be kept lower than before.
In addition, parts such as a pressure reducing valve, a pressure relief valve, a negative pressure operation valve, and a can body protection valve, which are necessary for a configuration using a pressure tank, are not necessary. Further, unlike the pressure tank, it is not necessary to form a cylindrical shape from the viewpoint of pressure resistance, and the degree of freedom in designing the tank shape can be increased.
[0018]
(Claims 10 Means)
Claim 5 The hot water supply temperature adjusting means described in 1 is a mixing valve provided downstream of the heat exchanger of the hot water supply pipe, a branch pipe branched from the hot water supply pipe upstream of the heat exchanger and connected to the mixing valve, and a mixing valve A water temperature sensor that detects the temperature of the hot water supply water downstream is provided, and the mixing ratio of hot water and water in the mixing valve can be adjusted based on the temperature detected by the water temperature sensor. According to this configuration, since the temperature of the hot water supply water can be controlled by adjusting the mixing ratio of hot water and water with the mixing valve, temperature control with respect to the set temperature is easy.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a schematic diagram showing a configuration of a hot water supply apparatus.
The hot water supply apparatus 1 of this embodiment is used for general household use, and includes a tank 2 for storing a heat storage fluid W, a heating means (to be described later) for heating the heat storage fluid W in the tank 2, and a tank 2 The electric pump 3 for pumping up the heat storage fluid W in the inside, and for hot water supply for exchanging heat between the heat storage fluid W pumped up by the electric pump 3 and the hot water supplied to the hot water supply pipes (the water supply pipe 4 and the hot water supply pipe 5) It is comprised from the heat exchanger 6, the control apparatus (pump control part 7 and cycle control part 8) etc. which control the action | operation of this hot water supply system.
[0020]
a) The tank 2 is opened to the atmosphere through the air hole 2a, and the inside of the tank 2 is maintained at atmospheric pressure. The tank 2 is formed of a resin material, for example, and is provided in a rectangular parallelepiped shape. In order to reduce the heat stored in the heat storage fluid W in the tank 2 from being released into the atmosphere from the wall surface of the tank 2, the outer periphery of the tank 2 may be covered with a heat insulating material such as glass wool or urethane. good.
The main component of the heat storage fluid W is water, and a preservative, an antifreezing agent, LLC, and the like are added as necessary.
[0021]
b) The heating means uses a supercritical heat pump cycle C in which, for example, carbon dioxide gas is used as a refrigerant, so that the refrigerant pressure on the high pressure side becomes equal to or higher than the critical pressure of the refrigerant.
The heat pump cycle C includes functional parts such as a compressor 9, a heat storage heat exchanger 10, an expansion valve 11, an evaporator 12, and an accumulator 13.
The compressor 9 is driven by a built-in electric motor (not shown), and compresses and discharges the gas-phase refrigerant sucked from the accumulator 13 to a critical pressure or higher.
[0022]
The heat storage heat exchanger 10 exchanges heat between the refrigerant and the heat storage fluid W. For example, a refrigerant passage 10a through which the refrigerant flows and a heat storage fluid passage 10b through which the heat storage fluid W flows are provided in a double tube structure. The counter flow type heat storage heat exchanger 10 is configured so that the flow direction of the refrigerant and the flow direction of the heat storage fluid W are opposed to each other.
The expansion valve 11 decompresses the refrigerant flowing out from the heat storage heat exchanger 10 and supplies the decompressed refrigerant to the evaporator 12.
The evaporator 12 evaporates the refrigerant decompressed by the expansion valve 11 by heat exchange with the atmosphere.
The accumulator 13 gas-liquid separates the refrigerant flowing out from the evaporator 12 and causes the compressor 9 to suck only the gas-phase refrigerant and stores excess refrigerant in the cycle.
[0023]
The heat storage fluid passage 10b of the heat storage heat exchanger 10 is connected to the tank 2 via an inflow pipe 14 and an outflow pipe 15, and the electric pump 16 provided in the inflow pipe 14 is activated to store heat in the tank 2. The working fluid W circulates. However, the upstream end of the inflow pipe 14 opens at the bottom of the tank 2, and the downstream end of the outflow pipe 15 opens at the top of the tank 2. As a result, the heat storage fluid W heated by heat exchange with the refrigerant in the heat storage heat exchanger 10 is sent to the upper part of the tank 2 through the outflow pipe 15, so that the upper part in the tank 2 moves from the lower side toward the lower side. The heat is sequentially stored in the heat storage fluid W. In addition, since the heat storage fluid W in the tank 2 only needs to secure a heat storage amount corresponding to the amount of hot water used in the home, the entire heat storage fluid in the tank 2 is not necessarily maintained at a high temperature.
[0024]
Therefore, in a home where the amount of hot water used is small, for example, heat may be stored in about half of the heat storage fluid W in the tank 2. In this case, in the tank 2, as shown in FIG. 1, due to the specific gravity difference due to the temperature of the heat storage fluid W, the heat storage fluid W <b> 1 having a higher temperature from the upper side toward the lower side in the tank 2, the heat storage at the intermediate temperature Naturally separated into a heat storage fluid W3 and a low temperature heat storage fluid W3, the intermediate temperature heat storage fluid W2 also serves to insulate between the high temperature heat storage fluid W1 and the low temperature heat storage fluid W3. The thickness is small compared to the entire heat storage fluid.
[0025]
c) The electric pump 3 is installed, for example, in the upper part of the tank 2, connected to the tank 2 through the suction pipe 17, and connected to the hot water supply heat exchanger 6 through the discharge pipe 18. In addition, the upstream end (suction port) of the suction pipe 17 is open to the upper part (high temperature heat storage fluid W1) in the tank 2. Therefore, when the electric pump 3 is operated, the heat storage fluid W1 having a high temperature can be pumped and pumped to the hot water supply heat exchanger 6.
[0026]
d) The hot water supply heat exchanger 6 includes a primary side passage 6a through which the heat storage fluid W pumped up by the electric pump 3 flows, and a secondary side passage 6b connected to the hot water supply pipes (the water supply pipe 4 and the hot water supply pipe 5). For example, as shown in FIG. 2, the inner tube 6B that forms the secondary passage 6b is inserted into the outer tube 6A that forms the primary passage 6a.
Here, the outer tube 6A preferably uses a resin material in order to keep heat loss low, and the inner tube 6B preferably uses a copper material having a high thermal conductivity. Further, the inner tube 6B may be a cylindrical tube as with the outer tube 6A. However, for example, as shown in FIG. In this case, the heat transfer area between the primary side passage 6a and the secondary side passage 6b increases, and the heat exchange efficiency between the heat storage fluid W and the hot water supply water can be improved.
[0027]
As shown in FIG. 1, the hot water supply heat exchanger 6 is arranged in the vertical direction inside the tank 2, and the upper end of the primary passage 6 a is connected to the electric pump 3 via the discharge pipe 18. The lower end (outlet) of the passage 6 a is open at the bottom of the tank 2. Further, the lower end of the secondary passage 6 b is connected to the water supply pipe 4 at the lower part in the tank 2, and the upper end protrudes to the upper part of the tank 2 and is connected to the hot water supply pipe 5. Accordingly, the hot water supply heat exchanger 6 has a flow direction of the heat storage fluid W flowing from the top to the bottom in the primary passage 6a and a secondary passage 6b from the bottom to the top, as indicated by arrows in FIG. It is configured as a counterflow type in which the flow direction of hot water for water flowing in the opposite direction. The water supply pipe 4 and the hot water supply pipe 5 are part of the hot water supply pipe.
[0028]
e) The control device includes a pump control unit 7 that controls the operation of the electric pump 3, and the pump control unit 7 detects hot water supply sensor 19 that detects the presence or absence of “water flow” and a water temperature that detects the temperature of hot water supply water. The detection signal of the sensor 20 is input, the ON / OFF control of the electric pump 3 is performed based on the detection result of the hot water detection sensor 19, and the rotation speed control of the electric pump 3 is performed based on the detection result of the water temperature sensor 20. The hot water detection sensor 19 is provided in the hot water supply pipe 4 or the hot water supply pipe 5, and the water temperature sensor 20 is provided in the hot water supply pipe 5.
[0029]
Further, the control device includes a cycle control unit 8 that controls an electric motor built in the compressor 9 of the heat pump cycle C and an electric pump 16 provided in the inflow pipe 14. The cycle control unit 8 is based on the detected temperature of the heat storage temperature sensor 21 that detects the temperature of the heat storage fluid after heating in order to keep the temperature of the heat storage fluid W heated by the heat storage heat exchanger 10 at a constant temperature. Thus, the rotational speed of the electric pump 16 is controlled.
[0030]
Next, the operation of this embodiment will be described.
The heat storage fluid W in the tank 2 is heated and stored by a necessary amount, for example, by operating the heat pump cycle C and the electric pump 16 using midnight power. Thereafter, when the user opens the hot water tap (not shown) and a water flow is generated in the hot water supply pipe (hot water supply pipe 5), a “water flow” is detected by the hot water detection sensor 19 and is output from the pump control unit 7. The electric pump 3 is activated in response to the signal (ON signal). When the electric pump 3 is operated, a high-temperature heat storage fluid W is pumped from the upper portion of the tank 2, and a flow of the heat storage fluid W is generated in the primary passage 6 a of the hot water supply heat exchanger 6. Thereby, the hot water supply water flowing through the secondary side passage 6b of the hot water supply heat exchanger 6 receives the heat energy of the heat storage fluid W and is heated.
[0031]
Here, the pump control unit 7 controls the driving state (the number of rotations) of the electric pump 3 so that the temperature of the hot water detected by the water temperature sensor 20 becomes a desired hot water supply temperature (a hot water supply temperature set by the user). To do. That is, when the hot water temperature detected by the water temperature sensor 20 is lower than the desired hot water supply temperature, the rotational speed of the electric pump 3 is increased to increase the circulation amount of the heat storage fluid W flowing through the primary passage 6a. As a result, the amount of heat exchange between the heat storage fluid W flowing through the primary passage 6a and the hot water supply water flowing through the secondary passage 6b increases, and the temperature of the hot water rises. When the temperature of the hot water detected by the water temperature sensor 20 is higher than the desired hot water supply temperature, the rotational speed of the electric pump 3 is reduced to reduce the circulation amount of the heat storage fluid W flowing through the primary side passage 6a. As a result, the amount of heat exchange between the heat storage fluid W flowing through the primary side passage 6a and the hot water supply water flowing through the secondary side passage 6b is reduced, so that the temperature of the hot water is lowered.
[0032]
(Effects of the first embodiment)
Since the hot water supply device 1 of the present embodiment has the hot water supply heat exchanger 6 disposed in the tank 2, heat exchange between the heat storage fluid W and the hot water supply water can be performed inside the tank 2. As a result, since heat loss due to heat radiation to the atmosphere is reduced, the hot water supply capacity can be improved accordingly. In addition, space can be saved as compared with the case where the hot water heat exchanger 6 is disposed outside the tank 2.
[0033]
In the present embodiment, since the atmosphere open type tank 2 is used, the pressure resistance design such as a pressure tank (sealed type tank) is not required, and therefore the tank 2 can be formed of resin. In this case, a pressing process and a welding process necessary for processing stainless steel, which is usually used as a tank material, are unnecessary, and the manufacturing cost can be kept lower than before. In addition, parts such as a pressure reducing valve, a pressure relief valve, a negative pressure operation valve, and a can body protection valve, which are necessary for a configuration using a pressure tank, are not necessary. Further, unlike the pressure tank, it is not necessary to form a cylindrical shape from the viewpoint of pressure resistance, and there is an effect that the degree of freedom in designing the tank shape can be increased.
[0034]
By making the inner pipe 6B of the hot water supply heat exchanger 6 uneven, it is possible to increase the heat exchange area between the primary side passage 6a through which the heat storage fluid W flows and the secondary side passage 6b through which hot water supply water flows. For this reason, heat exchange capability improves compared with the case where the inner side pipe 6B is comprised with a round tube, and it is possible to shorten the full length of the heat exchanger 6 for hot water supply.
Since the heat pump cycle C is used as the heating means for the heat storage fluid W, the running cost (mainly electricity bill) is much lower than that of the gas type or kerosene type heating means.
The heated heat storage fluid W can be used not only for hot water supply but also for floor heating and indoor air conditioning. Further, the heat storage fluid W can be used as hot water for a bath. In this case, since the heat storage fluid W can be used without heat loss, the entire heat storage amount can be effectively utilized.
[0035]
(Second embodiment)
This embodiment is an example in which a turbine is used as means for circulating the heat storage fluid W in the hot water supply heat exchanger 6.
As shown in FIG. 3, the turbine includes a first impeller 22 that rotates in response to the flow of hot water supply water, and a second impeller 23 that rotates by transmitting the rotation of the first impeller 22. Is done.
[0036]
The first impeller 22 is stored in a storage chamber 24 provided in the hot water supply pipe 5, and when a water flow is generated in the hot water supply pipe 5, the first impeller 22 can rotate at a rotation speed corresponding to the flow rate.
The second impeller 23 is accommodated in a storage chamber 25 provided between the suction pipe 17 and the discharge pipe 18 and can pump the heat storage fluid W pumped up by its own rotation to the primary passage 6a. .
The first impeller 22 and the second impeller 23 can be interlocked by the attractive force of a magnet (not shown) embedded in each. In this configuration, since it is not necessary to connect the first impeller 22 and the second impeller 23 by a shaft or the like, the storage chamber 24 and the storage chamber 25 can be completely separated, and hot water supply water and heat storage Mixing with the working fluid W cannot occur.
[0037]
According to the configuration of the present embodiment, the heat storage fluid W can be circulated to the primary side passage 6a only by the energy of the water flow generated in the hot water supply pipe 5, and therefore it is necessary to use the electric pump 3 shown in the first embodiment. There is no need for electric power for driving the electric pump 3.
In addition, if the piping pressure loss is designed so that the hot water flow rate, the rotational speed of each impeller 22 and 23, and the flow rate of the heat storage fluid W flowing through the primary passage 6a are the target hot water temperature, the first is performed. Since the hot water detection sensor 19, the water temperature sensor 20, and the pump controller 7 shown in the embodiment are not required, an inexpensive system can be provided.
[0038]
(Third embodiment)
In this embodiment, as shown in FIG. 4, the flow rate of the heat storage fluid W flowing through the primary passage 6 a is controlled by an electric flow control valve 26.
The electric flow control valve 26 is installed either before or after the electric pump 3, and receives a command from the pump control unit 7 to vary the heat storage fluid flow rate.
According to this configuration, since the heat storage fluid flow rate is varied by the electric flow control valve 26, the rotational speed of the electric pump 3 can be made constant. When the rotational speed of the electric pump 3 is changed as in the first embodiment, a speed variable circuit such as an inverter is required if it is alternating current. However, the speed variable circuit is made constant by making the rotational speed of the electric pump 3 constant. Is no longer necessary.
The configuration of the present embodiment (electric flow control valve 26) can also be applied to a system that uses the turbine shown in the second embodiment.
[0039]
(Fourth embodiment)
In the present embodiment, as shown in FIG. 5, the flow rate of the heat storage fluid W flowing through the primary passage 6 a is controlled by the temperature detection type flow control valve 27.
The temperature detection type flow control valve 27 has a gas sealing part 27a in which an inert gas is sealed, and has a structure in which the valve opening degree is varied according to the internal pressure of the gas sealing part 27a. Is installed at a position where the temperature of the hot water heated by the hot water heat exchanger 6 can be sensed.
For example, when the hot water supply temperature decreases, the temperature detection type flow control valve 27 increases the valve opening degree by decreasing the internal pressure of the gas sealing portion 27a, and increases the heat storage fluid flow rate to increase the hot water supply temperature. . Further, when the hot water supply temperature is increased, the internal pressure of the gas sealing portion 27a is increased so that the valve opening is reduced, and the hot water supply temperature is decreased by reducing the heat storage fluid flow rate.
[0040]
According to the configuration of the present embodiment, the temperature detection type flow control valve 27 works to maintain the hot water supply temperature at a desired set temperature mechanically, so that the rotational speed of the electric pump 3 is the same as in the third embodiment. Can be kept constant, and a speed variable circuit such as an inverter becomes unnecessary.
Moreover, since the temperature detection type flow control valve 27 has a structure in which the valve opening degree is varied in accordance with the internal pressure of the gas sealing portion 27a, the water temperature sensor 20 for detecting the temperature of the hot water supply water is unnecessary.
In addition, the structure (temperature detection type flow control valve 27) of a present Example is applicable also to the system which uses the turbine shown in 2nd Example.
[0041]
(5th Example)
The present embodiment is an example in which the temperature of hot water supply water is adjusted by mixing hot water heated by the hot water supply heat exchanger 6 with water before being heated by the hot water supply heat exchanger 6. Specifically, as shown in FIG. 6, it has a branch pipe 28 branchedly connected to the water supply pipe 4, and the downstream end of the branch pipe 28 is connected to a mixing valve 29 provided in the hot water supply pipe 5. Is done.
The mixing valve 29 varies the amount of water flowing from the branch pipe 28 and receives a command from the pump control unit 7 so that the temperature of the hot water supply water detected by the water temperature sensor 20 becomes the set hot water supply temperature. The amount of water is adjusted.
[0042]
According to this configuration, since the temperature of the hot water supply water can be adjusted by the mixing valve 29, the temperature control of the hot water supply water with respect to the set temperature is possible even if there is some temperature fluctuation in the hot water heated by the hot water supply heat exchanger 6. Can be performed with higher accuracy.
The configuration of this embodiment can also be applied to a system that uses the turbine shown in the second embodiment.
[0043]
(Sixth embodiment)
In this embodiment, as shown in FIG. 7, the heat storage heat exchanger 10 of the heat pump cycle C, which is a heating means, is arranged in the tank 2. Moreover, the electric pump 16 is provided in the outflow pipe 15 with the movement of the heat storage heat exchanger 10. As in the first embodiment, the rotational speed of the electric pump 16 is controlled by the cycle control unit 8 so that the heat storage fluid temperature detected by the heat storage temperature sensor 21 is constant.
[0044]
According to this configuration, since the heat storage heat exchanger 10 is arranged in the tank 2, the required volume of the heat pump cycle C configured outside the tank 2 can be reduced and the heat exchanger cycle can be made compact. Moreover, since the heat loss from the heat storage heat exchanger 10 to the atmosphere is eliminated, the heat storage capacity is improved.
The configuration of this embodiment can also be applied to a system using the turbine shown in the second embodiment.
[0045]
(Seventh embodiment)
In this embodiment, as shown in FIG. 8, the pump function for circulating the heat storage fluid W in the hot water supply heat exchanger 6 and the pump function for circulating the heat storage fluid W in the heat storage heat exchanger 10 are electrically operated. This is an example performed by the pump 30. In addition, the heat pump cycle C is the structure which has arrange | positioned the heat exchanger 10 for thermal storage in the tank 2 similarly to 6th Example.
In this case, since the heat storage operation and the hot water supply operation are performed by one electric pump 30, it is necessary to switch the circulation path of the heat storage fluid W between the case of performing the heat storage operation and the case of performing the hot water supply operation. Therefore, as shown in FIG. 8, three-way valves 31 and 32 are respectively arranged before and after the electric pump 30, and the passage directions of the three-way valves 31 and 32 are determined according to instructions from the control device 50 (pump control unit, cycle control unit). Switching.
[0046]
Here, the flow of the heat storage fluid W when the passage directions of the three-way valves 31 and 32 are switched will be described.
a) When storing heat
Lower part in tank 2 (low temperature heat storage fluid W3) → heat storage fluid passage 10b of the heat storage heat exchanger 10 → first outlet pipe 15a → three-way valve 31 → common pipe 33 → electric pump 30 → common pipe 34 → three-way valve 32 → The second outflow pipe 15b → the heat storage fluid W flows into the upper part of the tank 2 (high temperature heat storage fluid W1).
[0047]
b) During hot water supply
Upper part of tank 2 (high temperature heat storage fluid W1) → suction pipe 17 → three-way valve 31 → common pipe 33 → electric pump 30 → common pipe 34 → three-way valve 32 → discharge pipe 18 → primary side passage of hot water supply heat exchanger 6 6a → The heat storage fluid W flows to the lower part of the tank 2 (low temperature heat storage fluid W3).
According to the configuration of the present embodiment, the heat storage operation and the hot water supply operation can be performed by one electric pump 30, so that the cost can be reduced compared to the case where two electric pumps are used.
[0048]
(Eighth embodiment)
As in the seventh embodiment, the present embodiment has one pump function for circulating the heat storage fluid W in the hot water supply heat exchanger 6 and one pump function for circulating the heat storage fluid W in the heat storage heat exchanger 10. As shown in FIG. 9, the heat storage heat exchanger 10 of the heat pump cycle C is arranged outside the tank 2 (the same as in the first embodiment). In this case, the same operation and effect as the seventh embodiment can be obtained.
[0049]
(Ninth embodiment)
This embodiment is an example in which the electric pump 3 is disposed in the tank 2 as shown in FIG. In this case, since the heated heat storage fluid W is not taken out of the tank 2, the heat loss can be further reduced as compared with the case where only the hot water supply heat exchanger 6 is disposed in the tank 2.
In this embodiment, the electric pump 3 is used as a means for circulating the heat storage fluid W in the primary passage 6a of the hot water supply heat exchanger 6. However, when the turbine described in the second embodiment is used. However, the turbine (the first impeller 22 and the second impeller 23) may be disposed in the tank 2 in the same manner.
[0050]
(Tenth embodiment)
The present embodiment is an example of a hot water supply system in which a hot water supply heat exchanger 6 is arranged outside the tank 2 as shown in FIG.
The hot water supply apparatus 1 of the present embodiment includes a tank 2 for storing the heat storage fluid W, a heating means (to be described later) for heating the heat storage fluid W, an electric pump 3 for pumping up the heat storage fluid W in the tank 2, and this electric pump. 3 for mixing the heat storage fluid W pumped up by the heat storage water 6 and the hot water supply water, the hot water supply water heated by the hot water supply heat exchanger 6 and the hot water supply water before being heated. 29 and a control device (described below) for controlling the operation of the hot water supply device 1.
[0051]
The tank 2 is opened to the atmosphere through the air hole 2a, and the inside of the tank 2 is maintained at atmospheric pressure.
The heating means is, for example, a supercritical heat pump cycle C that uses carbon dioxide as a refrigerant, as in the first embodiment, and is connected to the tank 2 via the inflow pipe 14 and the outflow pipe 15 as in the first embodiment. ing. The fluid heating passage of the present invention includes the inflow pipe 14 that supplies the heat storage fluid W to the heat pump cycle C by the operation of the electric pump 16 from the bottom of the tank 2, and the heat storage fluid W heated in the heat pump cycle C. And an outflow pipe 15 for returning the gas to the upper part in the tank 2.
[0052]
The electric pump 3 pumps the heat storage fluid W from the upper part of the tank 2 through the suction pipe 17, pumps it to the hot water supply heat exchanger 6, and exchanges heat with the hot water supply water in the hot water supply heat exchanger 6. W is returned to the lower part in the tank 2. In this embodiment, the electric pump 3 is installed on the upstream side (pressure feeding side) of the hot water supply heat exchanger 6, but may be installed on the downstream side (suction side) of the hot water supply heat exchanger 6. .
[0053]
As shown in FIG. 2, the hot water supply heat exchanger 6 is provided in a double-pipe structure including an outer pipe 6A (first pipe) and an inner pipe 6B (second pipe). The heat storage fluid W flows through the annular primary passage 6a formed between the pipes 6A, and hot water supply water flows through the secondary passage 6b formed inside the inner pipe 6B. However, the flow direction of the heat storage fluid W flowing through the primary side passage 6a and the flow direction of the hot water supply water flowing through the secondary side passage 6b are configured as opposite flow types.
As with the fifth embodiment, the hot water supply pipe through which the hot water supply circulates is provided with a mixing valve 29 in the hot water supply pipe 5, and the downstream end of the branch pipe 28 branched from the water supply pipe 4 is connected to the mixing valve 29. Has been.
[0054]
The control device includes a pump control unit 7 that controls the operation of the electric pump 3 and a cycle control unit 8 that controls the operation of the heat pump cycle C.
In the pump control unit 7, signals are input from a first temperature sensor 51 and a flow rate sensor 54 provided in the water supply pipe 4, and a second temperature sensor 52 and a third temperature sensor 53 provided in the hot water supply pipe 5, respectively. Based on these signals, a predetermined calculation is performed in accordance with a program inputted in advance, and the rotational speed of the electric pump 3 is controlled according to the calculation result.
[0055]
The first temperature sensor 51 detects the temperature T2i of the hot water supply water (unheated hot water supply water) supplied to the water supply pipe 4, and the second temperature sensor 52 passes through the hot water supply heat exchanger 6. The temperature T2o of the heated hot water supply water is detected, and the third temperature sensor 53 detects the temperature T2 of the hot water supply water obtained by mixing the unheated hot water supply water and the heated hot water supply water with the mixing valve 29. . The flow rate sensor 54 detects the flow rate of hot water supplied to the water supply pipe 4.
In the cycle control unit 8, the rotational speed of the electric pump 16 is controlled based on the temperature detected by the heat storage temperature sensor 21 that detects the temperature of the heat storage fluid W after heating.
[0056]
Next, the operation of this system will be described.
The set temperature of the hot water supply device 1 can be set in increments of 1 ° C. within a range of 35 to 50 ° C. (normal use temperature), and the temperature of the hot water flowing out from the hot water heat exchanger 6 is set to 50 ° C. as a target temperature. The Note that the set temperature can be set to 50 ° C. or more. In this case, the set temperature + α is set as the target temperature, or the set temperature itself is set as the target temperature. In addition, the target temperature can be set to a set temperature + α (variation value) at a normal use temperature.
[0057]
In order to obtain a constant hot water supply water temperature, the feed water temperature detected by the first temperature sensor 51, the feed water flow rate detected by the flow sensor 54, and the temperature of the heat storage fluid W detected by the heat storage temperature sensor 21 are parameters. The flow rate of the heat storage fluid W is calculated from the relational expression In this case, the flow rate of the heat storage fluid W is calculated such that the lower the feed water temperature, the higher the feed water flow rate, and the lower the temperature of the heat storage fluid W, the greater the flow rate of the heat storage fluid W. By sufficiently transferring heat from the heat storage fluid W having the flow rate thus obtained to the hot water supply water, the temperature T1o of the heat storage fluid W after heat exchange can be lowered to the vicinity of the temperature T2i of the hot water supply water. (For example, the temperature difference ΔT is within 5 ° C.).
Of course, as a premise, the heat exchanger for hot water supply 6 needs to have a heat exchanging capacity capable of sufficiently transferring heat from the heat storage fluid W to the hot water supply water, and for that reason, the flow direction of the heat storage fluid W It is comprised as a counterflow type heat exchanger with which the flow direction of hot water supply water opposes.
[0058]
The above control is so-called feedforward control, which is obtained in consideration of the flow rate and temperature of the heat storage fluid W necessary for heating hot water having a certain flow rate and temperature to the target temperature.
For this reason, in the flow volume of the heat storage fluid W actually calculated, the heating temperature of the hot water supply water may be too high or too low with respect to the target temperature. For this reason, the temperature T2o of hot water actually heated by the second temperature sensor 52 may be detected, and the flow rate of the heat storage fluid W may be corrected so that the temperature becomes the target temperature.
[0059]
In addition, by setting the target temperature to a temperature that is a predetermined temperature higher than the normally used hot water temperature, the temperature of the hot water can be accurately adjusted to the actual hot water temperature. That is, if the temperature of the hot water supply water is directly adjusted by the flow rate control of the pump control unit 7 (flow rate control means), the temperature control accuracy may be lowered because the responsiveness of the temperature change is slow. However, when the hot water heated by the hot water supply heat exchanger 6 and the cold water before being heated are mixed using the mixing valve 29 as in the present embodiment, the temperature of the hot water is actually set to the temperature at which the hot water is supplied. Can be adjusted accurately. In this case, while the temperature T2 of the hot water supply actually used is detected by the third temperature sensor 53, the hot water supply water heated to the target temperature and the unheated hot water supply water are mixed by the mixing valve 29. The temperature of the hot water supply water can be lowered to the temperature at which hot water should be supplied.
Moreover, by setting the target temperature to a constant temperature higher than the normally used hot water temperature, it is possible to stably and accurately mix cold / hot water.
[0060]
In this hot water supply system, a supercritical heat pump cycle C is used as a heating means for the heat storage fluid W. In this supercritical heat pump cycle C, a high pressure (the discharge pressure of the compressor 9) depends on the temperature of the heat storage fluid W. Therefore, as the temperature of the heat storage fluid W decreases, the high pressure decreases and the operation can be performed in a region where the cycle efficiency is good. Therefore, the temperature of the heat storage fluid W stored in the lower part of the tank 2 is lowered to the vicinity of the temperature of the hot water supply water by the flow rate control described above, and the heat storage fluid W is introduced from the lower part of the tank 2 to By heating and returning to the upper part in the tank 2, the cycle efficiency of the heat pump cycle C is improved, and a power saving operation can be performed.
[0061]
The water supply temperature may be directly detected by the first temperature sensor 51, or may be obtained indirectly by estimating the water temperature from other parameters related to the water temperature. For example, since the outside air temperature and the water temperature are related, the water temperature may be estimated from the outside air temperature, the change in the average water temperature over the course of one year is memorized, and the water supply temperature should be regarded as a calendar function. The water temperature may be calculated.
Moreover, since the heat storage fluid W is heated so that the temperature of the heat storage fluid W becomes a predetermined target temperature on the heat pump cycle C side, the temperature of the heat storage fluid W can be obtained from the heat pump cycle C side. Is possible.
[0062]
If the target temperature is set in advance throughout the year as the temperature of the heat storage fluid W, the set target temperature may be used as the temperature of the heat storage fluid W.
The flow rate sensor 54 may be installed upstream of the branch point between the water supply pipe 4 and the branch pipe 28 or downstream of the mixing valve 29 to detect the entire hot water supply flow rate. In this case, from the values of the temperature sensors 51, 52, and 53, the flow rates of the hot water supply heat exchanger 6 and the branch pipe 28 can be estimated by calorie calculation.
[0063]
(Modification)
The tank 2 shown in each embodiment does not necessarily need to use a resin material, and may be formed of a metal material. Moreover, the shape of the tank 2 may not be a rectangular parallelepiped shape but may be a cylindrical shape, for example.
In the hot water supply heat exchanger 6 described in the first embodiment, the secondary side passage 6b is provided inside the primary side passage 6a, but conversely, the secondary side passage 6b is provided outside the primary side passage 6a. May be. Moreover, the material used for the inner tube 6B and the outer tube 6A described above is an example. For example, the inner tube 6B can use aluminum having high thermal conductivity, and the outer tube 6A can be made of metal. Furthermore, you may cover the outer peripheral surface of the heat exchanger 6 for hot water supply with the heat insulating material 35 (refer FIG. 2).
[0064]
Further, the hot water supply heat exchanger 6 shown in each embodiment is not limited to the double tube structure including the inner tube 6B and the outer tube 6A, and may be a multi-hole tube structure as shown in FIG. 12, for example. This is configured by adhering a primary side plate 36 in which a plurality of primary side passages 6a are formed and a secondary side plate 37 in which a plurality of secondary side passages 6b are similarly formed with an adhesive or the like. Each of the plates 36 and 37 can be made of copper, aluminum, or the like having high thermal conductivity, and the periphery of the two plates 36 and 37 that are bonded together may be covered with a heat insulating material 38.
The electric pump 3 and the turbine shown in each embodiment may be arranged in the tank 2. In this case, since the heated heat storage fluid W is not taken out of the tank 2, the heat loss can be further reduced as compared with the case where only the hot water supply heat exchanger 6 is disposed in the tank 2.
[Brief description of the drawings]
FIG. 1 is an overall view showing a configuration of a hot water supply apparatus (first embodiment).
FIG. 2 is a cross-sectional view of an outer tube and an inner tube that constitute a heat exchanger for hot water supply.
FIG. 3 is an overall view showing the configuration of a hot water supply apparatus (second embodiment).
FIG. 4 is a configuration diagram showing a flow rate control mechanism for a heat storage fluid (third embodiment).
FIG. 5 is a configuration diagram showing a flow rate control mechanism for a heat storage fluid (fourth embodiment).
FIG. 6 is an overall view showing a configuration of a hot water supply apparatus (fifth embodiment).
FIG. 7 is an overall view showing the configuration of a hot water supply apparatus (sixth embodiment).
FIG. 8 is an overall view showing the configuration of a hot water supply apparatus (seventh embodiment).
FIG. 9 is an overall view showing the configuration of a hot water supply apparatus (eighth embodiment).
FIG. 10 is an overall view showing a configuration of a hot water supply apparatus (9th embodiment).
FIG. 11 is an overall view showing the configuration of a hot water supply apparatus (a tenth embodiment).
FIG. 12 is a cross-sectional view of a heat exchanger for hot water supply (modified example).
FIG. 13 is a cross-sectional view of a conventional hot water supply apparatus.
[Explanation of symbols]
1 Water heater
2 tanks
3 Electric pump (pump means)
4 Water supply pipe (pipe for hot water supply)
5 Hot water supply pipe (Pipe for hot water supply)
6 Heat exchanger for hot water supply (opposite flow heat exchanger)
6A Outer pipe (first pipe)
6B Inner pipe (second pipe)
7 Pump controller (flow rate control means)
14 Inflow pipe (fluid heating passage)
15 Outflow pipe (fluid heating passage)
17 Suction pipe (circulation passage)
18 Discharge pipe (circulation passage)
20 Water temperature sensor (hot water temperature control means)
22 First impeller (pump means)
23 Second impeller (pump means)
26 Electric flow control valve (flow control valve)
27 Temperature detection flow control valve (flow control valve)
28 Branch piping (hot water temperature control means)
29 Mixing valve (hot water temperature control means)
35 Insulation
51 1st temperature sensor (1st temperature detection means)
52 2nd temperature sensor (2nd temperature detection means)
54 Flow rate sensor (flow rate detection means)
C heat pump cycle (heating means)
W Heat storage fluid

Claims

A tank for storing heat storage fluid;
Heating means for heating the heat storage fluid in the tank;
A first pipe through which the heat storage fluid circulates and a second pipe through which hot water supply water flows are provided adjacent to each other, and the heat storage fluid and hot water supply water are opposed to each other. A counter-flow heat exchanger that performs heat exchange;
A hot water supply pipe connected to the second pipe and leading hot water supply water to the terminal;
A circulation path for taking out the heat storage fluid heated from the upper part in the tank, passing the first pipe, and returning it to the lower part in the tank;
Pump means for circulating the heat storage fluid in the circulation passage;
Flow rate control means for controlling the flow rate of the heat storage fluid flowing through the first pipe through the circulation passage;
A fluid heating passage for taking out the heat storage fluid from the lower part in the tank and supplying it to the heating means, and returning the heat storage fluid heated by the heating means to the upper part in the tank;
Heat exchange with the heat storage fluid flowing through the first pipe, and mixing means for mixing the hot water and the unheated hot water flowing out of the second pipe,
The flow rate control means is
First temperature detecting means for detecting the temperature of hot water for water flowing into the second pipe;
Flow rate detecting means for detecting the flow rate of hot water for water passing through the second pipe,
Based on the target temperature of hot water supplied from the hot water pipe, the temperature of hot water detected by the first temperature detecting means, and the flow rate of hot water detected by the flow rate detecting means , Adjusting the flow rate of the heat storage fluid flowing through the first pipe so that the temperature difference between the temperature of the heat storage fluid and the temperature of the hot water supply water flowing into the second pipe falls within a predetermined range ;
The target temperature is set to a temperature that is higher by a predetermined temperature than the temperature at which hot water is actually supplied, and hot water heated up to the target temperature is mixed with unheated hot water by the mixing means, so that the temperature of the hot water is increased. The hot water supply device is characterized in that the temperature is lowered to a temperature at which the hot water should be supplied.

2. The hot water supply according to claim 1, wherein the heating means is a supercritical heat pump cycle in which a pressure of the refrigerant is equal to or higher than a critical pressure, and the heat storage fluid is heated by the refrigerant whose pressure is increased to the critical pressure or higher. apparatus.

The flow rate control means includes second temperature detection means for detecting the temperature of hot water for water flowing out from the second pipe,
As the temperature of the water for hot water supply to be detected by the second temperature detecting means becomes the target temperature, according to claim 1, characterized in that to correct the flow rate of the heat storage fluid flowing through the first pipe Water heater.

The hot water supply apparatus according to any one of claims 1 to 3, wherein the target temperature is set to a constant temperature higher than a normally used hot water temperature .

Hot water supply temperature adjustment means for adjusting the temperature of hot water for hot water supply by mixing the water heated by the heat exchanger with the hot water heated by the heat exchanger,
The hot water supply apparatus according to any one of claims 1 to 4, wherein the heat exchanger is disposed in the tank .

The hot water supply apparatus according to claim 5, wherein the circulation passage and the pump means are provided in the tank .

The hot water supply apparatus according to claim 5 or 6, wherein the heat exchanger is covered with a heat insulating material .

The pump means is provided with a first impeller that rotates in response to the energy of hot water flowing through the hot water supply pipe, and a second impeller that is provided in the circulation passage and is rotated by transmission of rotation of the first impeller. The hot water supply device according to any one of claims 5 to 7, further comprising an impeller, wherein the heat storage fluid is circulated through the circulation passage by the rotation of the second impeller .

The hot water supply apparatus according to any one of claims 1 to 8, wherein the tank is open to an atmospheric pressure .

The hot water supply temperature adjusting means includes:
A mixing valve provided downstream of the heat exchanger in the hot water supply pipe;
A branch pipe branched from the hot water supply pipe upstream of the heat exchanger and connected to the mixing valve;
A water temperature sensor that detects the temperature of the hot water supply downstream from the mixing valve;
6. The hot water supply apparatus according to claim 5 , wherein a mixing ratio of hot water and water in the mixing valve is adjusted based on a temperature detected by the water temperature sensor .