JP2004233009A

JP2004233009A - Operation control method of ice storage type water cooler

Info

Publication number: JP2004233009A
Application number: JP2003025046A
Authority: JP
Inventors: Tetsushi Nakai; 哲志中井; Koji Matsubayashi; 浩司松林; Taizo Matsukawa; 泰三松川; Shinji Horikawa; 伸二堀川
Original assignee: Miura Co Ltd
Current assignee: Miura Co Ltd
Priority date: 2003-01-31
Filing date: 2003-01-31
Publication date: 2004-08-19

Abstract

<P>PROBLEM TO BE SOLVED: To provide an operation control method of an ice storage type water cooler whereby freezing of a heat exchanger which frequently occurs at the end of the time of ice storage can be effectively prevented especially when an ice storage type water cooler of an external water supply system is used. <P>SOLUTION: In this operation control method of the ice storage type water cooler equipped with a freezer, the heat exchanger, an ice storage tank, and an external water supply passage intervening in a water supply passage for connecting the heat exchanger and the ice storage tank and supplying water from the outside, a water supply temperature of water flowing in the external water supply passage and/or an atmosphere temperature of the freezer is detected until a water level of the ice storage tank reaches a predetermined reference water level at the time of ice storage, an upper limit water level in accordance with the detected temperature is set when the water level of the ice storage tank reaches the reference water level, and an outlet temperature of the heat exchanger is adjusted so as to prevent supercooling when the water level of the ice storage tank is raised to the upper limit water level. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、空調設備や食品冷却装置等に冷水を供給する蓄氷型冷水装置の運転制御方法に関するものであり、特に、蓄氷時において熱交換器の凍結防止を目的とした、蓄氷型冷水装置の運転制御方法に関するものである。
【０００２】
【従来の技術】
従来、蓄氷型冷水装置としては、図７に示すように、蓄氷タンク３１、ポンプ３４及び熱交換器２１が水供給路３２で順次接続されるとともに、上記熱交換器２１と上記蓄氷タンク３１が水還流路３３で接続されてなる水循環路と、冷凍機１１と上記熱交換器２１がそれぞれ冷媒供給路１２と冷媒還流路１３で接続された冷媒循環路とからなり、これに加えて、上記水供給路３２に外部給水路４１を接続して、外部から常温水を供給するようにした、いわゆる外部給水方式を採用したものがある（例えば、特許文献１参照）。また、上記熱交換器２１は、外管２１ａを螺旋状に形成し、その内部に内管２１ｂを挿入した二重管構造であって、外管２１ａと内管２１ｂとの間に蓄氷タンク３１から供給される水が流通し、内管２１ｂには冷凍機１１より供給される冷媒が流通する。この蓄氷型冷水装置は、電力料金の安い深夜電力を利用して、蓄氷タンク３１内に蓄熱媒体としての氷を蓄えておき、負荷の要求に応じて蓄氷タンク３１の上方から配管を通じて解氷水を供給して、タンク３１下部より冷水を取り出して使用される。
【０００３】
このタイプの蓄氷型冷水装置の製氷運転は、概略次のように行なわれる。まず、蓄氷タンク３１に所定水位まで蓄熱媒体としての水を満たした後、冷凍機１１を起動して、冷媒を熱交換器２１内に供給して循環させるとともに、蓄氷タンク３１内にある水を熱交換器２１へ送り込んで熱交換し、この熱交換により過冷却状態とされた水を蓄氷タンク３１内へ還流する。そして、この還流された水は所定の過冷却解除作用を受けることにより、スラリー状の氷を生成し、これにより製氷が始まる。
【０００４】
蓄氷タンク３１内で蓄氷がある程度進むと、水循環路を流通する水の温度が低下して熱交換器２１内で凍結が起きやすくなる。このような凍結が頻繁に発生すると製氷効率が悪化する。そこで、これを回避するために、外部給水方式による蓄氷型冷水装置では、外部給水路４１に設けた流量調節弁４３の開度を調節して、水供給路３２を流通する冷水の温度に応じた量の常温水を外部から供給して冷水と混合することにより、所定温度の冷水とし、さらにこの冷水の循環流量を一定にして熱交換器２１へ供給する。
【０００５】
ところで、蓄氷が進んで蓄氷タンク３１内の水位がある程度高くなると、氷が熱交換器２１の出口に向かって氷筍となって登って行き、熱交換器２１が凍結に至ることがしばしばある。そこで、従来では、かかる熱交換器２１の凍結が発生した場合、例えば、冷凍機１１の運転を停止するとともに、外部給水路４１から常温水を所定時間供給する等の凍結解除動作を行なった後、さらに熱交換器２１の出口を流通する水を過冷却にならない温度に調節することが行なわれている（例えば、特許文献２参照）。しかしながら、かかる運転方法では、せっかく製氷した氷を一部解かすことになるので、蓄氷量が低下することは避けられない。
【０００６】
【特許文献１】
特開平９−１５２１４９号公報（文献１）
【特許文献２】
特開平９−１６６３７４号公報（文献２）
【０００７】
【発明が解決しようとする課題】
本発明は、かかる事情に鑑みてなされたものであり、特に、外部給水方式の蓄氷型冷水装置を用いた場合に、蓄氷時の終期に頻発する熱交換器の凍結を効果的に防止することのできる蓄氷型冷水装置の運転制御方法を提供することを主たる目的とするものである。
【０００８】
【課題を解決するための手段】
上記目的を達成するため、本発明は、冷凍機と、この冷凍機から吐出される冷媒と熱交換することにより蓄熱媒体を過冷却状態とする熱交換器と、上記蓄熱媒体が収容されるとともに、蓄熱媒体の過冷却の解除により生成した氷を蓄える蓄氷タンクとを備え、上記熱交換器と上記蓄氷タンクを接続する水供給路には、外部から水を供給するための外部給水路が介設されてなる蓄氷型冷水装置の運転制御方法において、蓄氷時において、上記外部給水路を流通する水の給水温度及び／又は上記冷凍機の雰囲気温度を検知し、次いで、蓄氷タンクの水位があらかじめ設定された基準水位に達したとき、上記検知された温度に対応した上限水位を設定し、上記蓄氷タンクの水位が上限水位まで上昇すると、熱交換器の出口温度を過冷却にならない温度に調節することを特徴とする。
【０００９】
また、本発明では、上記の上限水位は、蓄氷タンクの水位が基準水位に達したときに検知された温度若しくは蓄氷タンクの水位が基準水位に達するまでに検知された平均温度に基づいて設定することが好ましい。
【００１０】
また、上記の運転制御方法を効果的に達成できる蓄氷型冷水装置としては、冷凍機と、この冷凍機から吐出される冷媒と熱交換することにより蓄熱媒体を過冷却状態とする熱交換器と、上記蓄熱媒体が収容されるとともに、蓄熱媒体の過冷却の解除により生成した氷を蓄える蓄氷タンクと、上記熱交換器と上記蓄氷タンクを接続する水供給路に介設された、外部から水を供給する外部給水路と、上記蓄氷タンクに設けられた水位検出手段とを備え、蓄氷時において、上記外部給水路を流通する水の給水温度及び／又は上記冷凍機の雰囲気温度を検知し、次いで、蓄氷タンクの水位があらかじめ設定された基準水位に達したとき、上記検知された温度に対応した上限水位を設定し、上記蓄氷タンクの水位が上限水位まで上昇すると、熱交換器の出口温度を過冷却にならない温度に調節する制御手段を備えることが好ましい。
【００１１】
【発明の実施の形態】
本発明は、いわゆる外部給水方式を採用した蓄氷型冷水装置に適用される運転制御方法であり、特に蓄氷終期に頻発する熱交換器の凍結を効果的に防止するために好適な運転制御方法である。
【００１２】
本発明の運転制御方法を実現するためには、冷凍機と、この冷凍機から吐出される冷媒と熱交換することにより蓄熱媒体を過冷却状態とする熱交換器と、上記蓄熱媒体が収容されるとともに、蓄熱媒体の過冷却の解除により生成した氷を蓄える蓄氷タンクと、上記熱交換器と上記蓄氷タンクを接続する水供給路に介設された、外部から水を供給する外部給水路と、上記蓄氷タンクに設けられた水位検出手段とから概略構成される蓄氷型冷水装置を用いることが好適である。ここで、前記冷凍機から吐出される冷媒とは、具体的には、圧縮機から吐出され、凝縮器にて凝縮されて液状となった冷媒が減圧されて気化されたものをいう。
【００１３】
そして、本発明の運転制御方法は、蓄氷時において、上記外部給水路を流通する水の給水温度及び／又は上記冷凍機（具体的には前記凝縮器）の雰囲気温度を検知し、次いで、蓄氷タンクの水位があらかじめ設定された基準水位に達したとき、上記検知された温度に対応した上限水位を設定し、上記蓄氷タンクの水位が上限水位まで上昇すると、熱交換器の出口温度を過冷却にならない温度に調節することを要旨とするものである。
【００１４】
外部給水方式による蓄氷型冷水装置では、上述した如く、水供給路を流通する冷水の温度に応じた量の常温水を外部から供給して冷水と混合することにより、所定温度の冷水とし、さらにこの冷水の循環流量を一定にして熱交換器へ供給することにより製氷運転を行なう。そして、製氷時においては、上記蓄氷型冷水装置を構成する蓄氷タンクの水位は徐々に高くなり、このままの状態で製氷運転を続けた場合、蓄氷終期において、氷が熱交換器の出口に向かって氷筍となって登って行き、熱交換器が凍結に至ることがしばしばある。
【００１５】
上記熱交換器の凍結現象は、蓄氷量がある限度を超えた場合に生じるものであるが、外部給水方式を採用する蓄氷型冷水装置にあっては、その蓄氷量は、製氷運転前における蓄氷タンクの貯水量だけで一義的に定まるものではなく、外部給水路を流通する常温水の給水温度や冷凍機の雰囲気温度によって変動する。
【００１６】
具体的に説明すると、過冷却度、循環流量、蓄氷タンクの有効貯水量及び熱交換器の入口温度を一定として、熱量保存の関係を考慮すると、蓄氷量は、給水温度が高いほど増加する。他方、冷凍機は、その周囲の温度が低下すると、冷却能力が増加する。この結果、過冷却度が増加するため、結果として、冷凍機の雰囲気温度が低いほど蓄氷量が増加する。したがって、蓄氷終期にあっては、たとえ蓄氷タンクの水位が同じでも、その時の蓄氷能力に応じて熱交換器が凍結に至るまでの時間が変動する場合もある。すなわち、外部給水方式を採用した蓄氷型冷水装置を用いる場合には、蓄氷能力が大きいほど短時間で熱交換器が凍結に至る。
【００１７】
そこで、本発明では、蓄氷時において、上記蓄氷タンクの水位が、あらかじめ設定された基準水位に達するまでは、上記外部給水路を流通する水の給水温度若しくは冷凍機の雰囲気温度のどちらか一方、または給水温度と冷凍機の雰囲気温度の両方を検知し、次いで、蓄氷タンクの水位が上記基準水位に達したとき、上記検知された温度に対応した上限水位を設定し、上記蓄氷タンクの水位が上限水位まで上昇すると、熱交換器の出口温度を過冷却にならない温度に調節する。
【００１８】
ここで、本発明において上限水位とは、その水位に達した時点で、非過冷却状態とされた蓄熱媒体（例えば、０．１℃程度の冷水）を所定量蓄氷タンクに供給すれば熱交換器の凍結を避けることができる限界水位のことであり、この水位は熱交換器の凍結速度に影響を与える給水温度や冷凍機の雰囲気温度の条件に応じて、あらかじめ設定された複数の水位のうちから一つを選択して定められるものである。また、本発明において基準水位とは、上記上限水位としてあらかじめ設定された複数の水位のうち、最低水位よりも低い水位をいう。
【００１９】
続いて、蓄氷タンクの水位に分けて、本発明の運転制御方法を詳細に説明する。まず、蓄氷タンクの水位が基準水位に達するまでは、蓄氷タンクが設置される環境に応じて、外部給水路を流通する水の給水温度若しくは冷凍機の雰囲気温度のどちらか一方、または給水温度と冷凍機の雰囲気温度の両方を検知する。検知する対象としては、例えば、冷凍機が屋内に設置されていて、冷凍機の運転中において、外気温度の変化が比較的小さい場合には、給水温度のみを検知すればよい。また、冷凍機が屋外に設置されていて、外気温度の変化が比較的大きい場合には、冷凍機の雰囲気温度（屋外温度）のみ、あるいは給水温度と冷凍機の雰囲気温度の両方を検知すればよい。
【００２０】
上記の温度は、温度センサを用いて常時検知することが好ましい。また、基準水位や後述する上限水位は、上記水位検出手段を用いて検出されるが、この水位検出手段としては、電極棒方式、フロート方式、水圧検出方式など公知の水位検出装置を採用することができる。そして、温度センサと水位検出手段は、ともに回線を介して制御器に接続されている。
【００２１】
つぎに、蓄氷タンクの水位が基準水位に達したときは、上記検知された温度に対応した上限水位が設定される。ここで、上限水位が設定されるとは、あらかじめ設定された複数の上限水位のうちから一つを選択することをいう。具体的には、給水温度のみを検知する場合にあっては、検知された給水温度があらかじめ設定した温度より高いときは、あらかじめ設定した複数の上限水位のうち、低い方の水位を選択し、他方、検知された給水温度があらかじめ設定した温度より低いときは、あらかじめ設定した複数の上限水位のうち、高い方の水位を選択する。
【００２２】
また、冷凍機の雰囲気温度のみを検知する場合にあっては、検知された雰囲気温度があらかじめ設定した温度より低いときは、あらかじめ設定した複数の上限水位のうち、低い方の水位を選択し、他方、検知された雰囲気温度があらかじめ設定した温度より高いときは、あらかじめ設定した複数の上限水位のうち、高い方の水位を選択する。
【００２３】
また、給水温度と冷凍機の雰囲気温度の両方を検知する場合には、上記の方法を組み合わせることになる。具体的には、検知された給水温度があらかじめ設定した温度より低いかどうか、検知された冷凍機の雰囲気温度があらかじめ設定した温度より高いかどうかにより４つの場合分けがあるが、（１）給水温度が設定温度よりも低く、雰囲気温度が設定温度よりも高いときは、あらかじめ設定した４つの上限水位のうち最も高い水位（Ｈａ）を選択し、（２）給水温度が設定温度よりも低く、雰囲気温度が設定温度よりも低いときは、あらかじめ設定した４つの上限水位のうち２番目に高い水位（Ｈｂ）を選択する。また、（３）給水温度が設定温度よりも高く、雰囲気温度が設定温度よりも高いときは、あらかじめ設定した４つの上限水位のうち３番目に高い水位（Ｈｃ）を選択し、（４）給水温度が設定温度よりも高く、雰囲気温度が設定温度よりも低いときは、あらかじめ設定した４つの上限水位のうち４番目に高い水位（Ｈｄ）（すなわち、最低上限水位）を選択する。
【００２４】
ここで、本発明では、上限水位としてＨａ＞Ｈｂ≧Ｈｃ≧Ｈｄであれば良く、例えば上記４パターンのうち、熱交換器の凍結速度は上記（１）の場合が他の場合に比べて最も遅いので、上限水位として、（１）の場合に選択する上限水位と、（２）・（３）・（４）のいずれの場合にも選択する共通の上限水位の２通りに分けるようにしてもよい。
【００２５】
また、本発明では、上限水位を選択する際の指標となる検知温度は、蓄氷タンクの水位が基準水位に達したときに検知された温度のみを基準としてもよいし、蓄氷タンクの水位が基準水位に達するまでに検知された平均温度を基準としてもよい。前者は、蓄氷運転中に温度変化がほとんどない場合に好適な基準となり、後者は、蓄氷運転中に温度変化が激しい場合に好適な基準となるものである。
【００２６】
そして、蓄氷タンクの水位が上記で設定された上限水位まで上昇すると、熱交換器の出口温度が過冷却にならない温度（例えば、０．２〜０．３℃程度）に調節する。具体的には、上記外部給水路に設けた温度調節手段を用いて、常温水と水供給路を流通する冷水とを混合して上記温度よりやや高い温度の冷水とし、これを熱交換器の入口へ供給することにより、熱交換器の出口温度が過冷却にならない温度に調節する。この温度調節は、蓄氷タンクの水位が最終水位に到達するまで続け、これで製氷運転を終了する。ここで、上記温度調節手段による温度調節方法としては、流量調節弁（例えば、モータバルブ、比例制御弁）を用いた、弁の開度の調整による常温水の流量調整による方法、電熱ヒーターなどの加熱手段を用いた、常温水の直接的な温度調整による方法などが挙げられる。
【００２７】
以上説明した運転制御方法によれば、蓄氷タンクの水位が上限水位に達した後、蓄氷タンク内へ非過冷却状態の蓄熱媒体（水）が必要最小限供給されて、かつ熱交換器の凍結を生じることなく蓄氷工程が終了する。したがって、本発明は、従来技術に比べて、蓄氷量（率）を向上させることができるとともに、蓄氷時間を短縮して省エネルギー化を図ることができる。
【００２８】
【実施例】
以下、本発明の実施例を図面に基づいて詳細に説明する。図１は、本発明の運転制御方法が適用される蓄氷型冷水装置の第１実施例を示す概略構成図である。
【００２９】
図１において、蓄氷型冷水装置は、冷凍機１１と熱交換器２１と蓄氷タンク３１とから概略構成されており、冷凍機１１と熱交換器２１はそれぞれ冷媒供給路１２と冷媒還流路１３で接続されて、全体として冷媒循環路を構成している。また、蓄氷タンク３１、第１温度センサ３５、ポンプ３４、及び熱交換器２１が水供給路３２で順次接続されるとともに、熱交換器２１と蓄氷タンク３１が水還流路３３で接続されて、全体として水循環路を構成している。そして、上記水供給路３２に介設された第１温度センサ３５と蓄氷タンク３１との間には、外部から常温水を供給する外部給水路４１が接続されている。この外部給水路４１には、水供給路３２に向かって、第２温度センサ４２と流量調節弁４３が接続されている。ここで、上記熱交換器２１は、上述した図７と同型の熱交換器を使用している。
【００３０】
蓄氷タンク３１内には、水位検出手段として、電極棒方式の水位検出装置３６が設けられている。この水位検出装置３６は、Ｌ、Ｓ、Ｈ１、Ｈ２、Ｈの５本の電極棒により構成されており、それぞれの電極棒の下端部をそれぞれ下限水位（Ｌ）、基準水位（Ｓ）、第１上限水位（Ｈ１）、第２上限水位（Ｈ２）及び最終水位（Ｈ）として検出する。そして、上記第１温度センサ３５、第２温度センサ４２、流量調節弁４３、水位検出装置３６は信号線を介して制御器５１にそれぞれ接続されている。
【００３１】
つぎに、上記構成の蓄氷型冷水装置を用いた製氷運転を図２に基づいて説明する。まず、蓄氷タンクの下限水位（Ｌ）まで蓄熱媒体としての水を入れた後、冷凍機１１を起動して、冷媒を熱交換器２１に供給して循環させるとともに、ポンプ３４を起動して蓄氷タンク３１内の水を水供給路３２を介して上記熱交換器２１へ供給する。そして、熱交換により過冷却状態とされた過冷却水は水還流路３３を経て蓄氷タンクに還流し、さらに水面に衝突することにより過冷却状態が解除されてスラリー状の氷を生成し、これにより製氷が始まる（ステップＳ１）。
【００３２】
しばらくすると、水供給路３２を流通する冷水の温度が低下してくるが、この場合は、第１温度センサ３５で検知された温度条件に基づいて、外部給水路４１に設けた流量調節弁４３の開度を調節して、上記水供給路３２を流通する冷水の温度に応じた量の常温水を供給して、上記冷水と混合することにより所定温度の冷水とする。また、これと並行して、第２温度センサ４２を用いて、外部給水路４１を流通する常温水の給水温度を常時検知する。
【００３３】
製氷が進んで、蓄氷タンク３１の水位が基準水位（Ｓ）に達したとき、給水温度が２０℃未満かどうかを判断して（ステップＳ２）、この基準水位で検知された給水温度に応じた上限水位が設定される。具体的には、給水温度が２０℃未満のときは、第２上限水位（Ｈ２）が選択され（ステップＳ３）、他方、給水温度が２０℃以上のときは、第１上限水位（Ｈ１）が選択される（ステップＳ４）。そして、蓄氷タンク３１の水位が上記選択された上限水位まで上昇すると、第１温度センサ３５からの信号に基づき、外部給水路４１に設けた流量調節弁４３の開度を調節して、所定流量に調節した常温水を水供給路３２に供給することにより、熱交換器２１の出口で過冷却にならない温度（０．２℃）の冷水を供給する（ステップＳ５）。そして、蓄氷タンク３１の水位が最終水位（Ｈ）に達したかどうか判定し（ステップＳ６）、達した時点で蓄氷を終了する（ステップＳ７）。以上説明したように、本実施例の運転制御方法によれば、蓄氷タンク３１の水位が上限水位に達した後、蓄氷タンク内へ非過冷却状態の蓄熱媒体（水）が必要最小限供給されて、かつ熱交換器の凍結を生じることなく蓄氷工程が終了する。
【００３４】
つぎに、本発明の第２実施例を図３に基づいて説明する。図３に示す実施例は、図１で示した給水温度を検知する代わりに、冷凍機を構成する凝縮器の雰囲気温度（本実施例では外気温度に相当する）を検知するものである。この冷凍機の雰囲気温度は、冷凍機１１の近くに設置された第３温度センサ１４を用いて検知される。本実施例に適用される蓄氷型冷水装置の基本構成は、上記第１実施例によるものと基本的に同じであり、相違点は、第１実施例では、外部給水路４１に第２温度センサ４２を設けて給水温度を検知するのに対して、本実施例では、冷凍機１１の近くに第３温度センサ１４を設けて冷凍機１１の雰囲気温度を検知する点にある。また、本実施例では、上限水位を設定する条件として、基準水位（Ｓ）に達したとき、冷凍機１１の雰囲気温度が２０℃以上かどうかを判定する（図４のステップＳ８）。雰囲気温度が２０℃以上のときは、第２上限水位（Ｈ２）が選択され（同図のステップＳ３）、他方、給水温度が２０℃未満のときは、第１上限水位（Ｈ１）が選択される（同図のステップＳ４）。以下、図４において、図２と同じ符号を付した処理は、同じ処理を示すものであり、説明は省略する。
【００３５】
つぎに、本発明の第３実施例を図５に基づいて説明する。図５に示す実施例は、給水温度と冷凍機の雰囲気温度（本実施例では、外気温度に相当する）の両方を検知するものである。本実施例による蓄氷型冷水装置の運転制御方法は、上記第１実施例と第２実施例を組み合わせたものである（図６参照）。具体的には、蓄氷タンク３１の水位が基準水位（Ｓ）に達したとき、まず、給水温度が２０℃未満かどうかを判定する（ステップＳ２）。給水温度が２０℃未満のときは、これに続けて雰囲気温度が２０℃以上かどうかを判定する（ステップＳ８）。そして、雰囲気温度が２０℃以上のときは、第２上限水位（Ｈ２）が選択され（ステップＳ３）、他方、これ以外の判定結果がでたときは、第１上限水位（Ｈ１）が選択される（ステップＳ４）。以下、図６において、図２及び図４と同じ符号を付した処理は、同じ処理を示すものであり、説明は省略する。
【００３６】
【発明の効果】
以上説明したように、本発明にかかる蓄氷型冷水装置の運転制御方法によれば、蓄氷タンクの水位が上限水位に達した後、蓄氷タンク内へ非過冷却状態の蓄熱媒体（水）が必要最小限供給されて、かつ熱交換器の凍結を生じることなく蓄氷工程が終了するとともに、蓄氷量（率）を向上させることができ、さらに蓄氷時間を短縮して省エネルギー化を図ることができる。
【図面の簡単な説明】
【図１】本発明の運転制御方法が適用される蓄氷型冷水装置の第１実施例を示す概略構成図である。
【図２】図１の蓄氷型冷水装置における運転制御方法を示すフローチャートである。
【図３】本発明の運転制御方法が適用される蓄氷型冷水装置の第２実施例を示す概略構成図である。
【図４】図３の蓄氷型冷水装置における運転制御方法を示すフローチャートである。
【図５】本発明の運転制御方法が適用される蓄氷型冷水装置の第３実施例を示す概略構成図である。
【図６】図５の蓄氷型冷水装置における運転制御方法を示すフローチャートである。
【図７】従来の蓄氷型冷水装置を示す概略構成図である。
【符号の説明】
１１冷凍機
１２冷媒供給路
１３冷媒還流路
１４第３温度センサ
２１熱交換器
２１ａ外管
２１ｂ内管
３１蓄氷タンク
３２水供給路
３３水還流路
３４ポンプ
３５第１温度センサ
３６水位検出装置
４１外部給水路
４２第２温度センサ
４３流量調節弁
５１制御器[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an operation control method of an ice storage type chilled water device for supplying cold water to an air conditioner, a food cooling device, and the like, and particularly to an ice storage type chiller for preventing a heat exchanger from freezing during ice storage. The present invention relates to an operation control method for a chilled water device.
[0002]
[Prior art]
Conventionally, as an ice storage type chilled water device, as shown in FIG. 7, an ice storage tank 31, a pump 34 and a heat exchanger 21 are sequentially connected by a water supply path 32, and the heat exchanger 21 and the ice storage A water circulation path in which the tank 31 is connected by a water return path 33, and a refrigerant circulation path in which the refrigerator 11 and the heat exchanger 21 are connected by a refrigerant supply path 12 and a refrigerant return path 13, respectively, are additionally provided. There is a so-called external water supply system in which an external water supply path 41 is connected to the water supply path 32 to supply room-temperature water from outside (for example, see Patent Document 1). The heat exchanger 21 has a double pipe structure in which an outer pipe 21a is formed in a spiral shape and an inner pipe 21b is inserted therein, and an ice storage tank is provided between the outer pipe 21a and the inner pipe 21b. The water supplied from 31 flows, and the refrigerant supplied from refrigerator 11 flows through inner tube 21b. This ice storage type chilled water device stores ice as a heat storage medium in the ice storage tank 31 by using late-night power at a low electricity rate, and through a pipe from above the ice storage tank 31 in response to a load request. Defrosting water is supplied, and cold water is taken out from the lower part of the tank 31 and used.
[0003]
The ice making operation of this type of ice storage type chiller is performed as follows. First, after the ice storage tank 31 is filled with water as a heat storage medium to a predetermined water level, the refrigerator 11 is started to supply and circulate the refrigerant into the heat exchanger 21 and to store the refrigerant in the ice storage tank 31. The water is sent to the heat exchanger 21 for heat exchange, and the supercooled water is returned to the ice storage tank 31 by the heat exchange. Then, the recirculated water undergoes a predetermined supercooling release action, thereby generating slurry ice, thereby starting ice making.
[0004]
When the ice storage progresses to a certain extent in the ice storage tank 31, the temperature of the water flowing through the water circulation path decreases, and freezing easily occurs in the heat exchanger 21. Frequent occurrence of such freezing deteriorates the ice making efficiency. Therefore, in order to avoid this, in the ice storage type chilled water device using the external water supply system, the opening degree of the flow control valve 43 provided in the external water supply passage 41 is adjusted to adjust the temperature of the cold water flowing through the water supply passage 32. An appropriate amount of room temperature water is supplied from the outside and mixed with the cold water to make cold water of a predetermined temperature, and further, the cooling water is supplied to the heat exchanger 21 at a constant circulation flow rate.
[0005]
By the way, when the ice storage advances and the water level in the ice storage tank 31 rises to a certain extent, the ice climbs as ice bamboo shoots toward the exit of the heat exchanger 21 and the heat exchanger 21 often freezes. is there. Therefore, conventionally, when the heat exchanger 21 is frozen, for example, after the operation of the refrigerator 11 is stopped, and after the freezing release operation such as supplying normal temperature water from the external water supply channel 41 for a predetermined time is performed, Further, the water flowing through the outlet of the heat exchanger 21 is adjusted to a temperature at which the water does not become supercooled (for example, see Patent Document 2). However, in such an operation method, since the ice that has been made is partially melted, it is inevitable that the ice storage amount is reduced.
[0006]
[Patent Document 1]
JP-A-9-152149 (Reference 1)
[Patent Document 2]
JP-A-9-166374 (Reference 2)
[0007]
[Problems to be solved by the invention]
The present invention has been made in view of such circumstances, and in particular, when an external water supply type ice storage chiller is used, it is possible to effectively prevent the heat exchanger from frequently freezing at the end of ice storage. It is a main object of the present invention to provide an operation control method for an ice storage type chilled water device that can perform the operation.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a refrigerator, a heat exchanger that superheats the heat storage medium by exchanging heat with a refrigerant discharged from the refrigerator, and the heat storage medium is housed therein. An ice storage tank for storing ice generated by releasing supercooling of the heat storage medium, and a water supply path connecting the heat exchanger and the ice storage tank has an external water supply path for supplying water from outside. In the operation control method of the ice storage type chilled water device provided with the above, at the time of ice storage, the water supply temperature of the water flowing through the external water supply passage and / or the ambient temperature of the refrigerator is detected, and then the ice storage is performed. When the water level in the tank reaches a preset reference water level, an upper limit water level corresponding to the detected temperature is set, and when the water level in the ice storage tank rises to the upper limit water level, the outlet temperature of the heat exchanger is exceeded. Temperature that does not cool And adjusting the.
[0009]
In the present invention, the upper limit water level is based on a temperature detected when the water level of the ice storage tank reaches the reference water level or an average temperature detected until the water level of the ice storage tank reaches the reference water level. It is preferable to set.
[0010]
Further, the ice storage type chilled water device that can effectively achieve the above operation control method includes a refrigerator and a heat exchanger that exchanges heat with a refrigerant discharged from the refrigerator to make a heat storage medium in a supercooled state. And the heat storage medium is accommodated, and an ice storage tank for storing ice generated by releasing the supercooling of the heat storage medium, and a water supply path connecting the heat exchanger and the ice storage tank are provided. An external water supply channel for supplying water from the outside; and a water level detecting means provided in the ice storage tank, wherein at the time of ice storage, a water supply temperature of water flowing through the external water supply channel and / or an atmosphere of the refrigerator. Temperature is detected, and then, when the water level of the ice storage tank reaches a preset reference water level, an upper limit water level corresponding to the detected temperature is set, and when the water level of the ice storage tank rises to the upper limit water level. , Heat exchanger Preferably includes a control means for regulating the temperature that does not mouth temperature supercooled.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention relates to an operation control method applied to an ice storage type chilled water device employing a so-called external water supply system, and in particular, an operation control method suitable for effectively preventing freezing of a heat exchanger which frequently occurs at the end of ice storage. Is the way.
[0012]
In order to realize the operation control method of the present invention, a refrigerator, a heat exchanger that superheats the heat storage medium by exchanging heat with the refrigerant discharged from the refrigerator, and the heat storage medium are housed. And an external water supply for supplying water from the outside, which is provided in an ice storage tank for storing ice generated by canceling the supercooling of the heat storage medium and a water supply path connecting the heat exchanger and the ice storage tank. It is preferable to use an ice storage type chilled water device that is roughly composed of a road and water level detection means provided in the ice storage tank. Here, the refrigerant discharged from the refrigerator specifically means a refrigerant discharged from the compressor and condensed by the condenser to be in a liquid state, which is decompressed and vaporized.
[0013]
Then, the operation control method of the present invention detects the supply temperature of water flowing through the external water supply channel and / or the ambient temperature of the refrigerator (specifically, the condenser) during ice storage, When the water level of the ice storage tank reaches a preset reference water level, an upper limit water level corresponding to the detected temperature is set, and when the water level of the ice storage tank rises to the upper limit water level, the outlet temperature of the heat exchanger is increased. Is adjusted to a temperature that does not cause supercooling.
[0014]
In the ice storage type chilled water device by the external water supply method, as described above, the normal temperature water in an amount corresponding to the temperature of the chilled water flowing through the water supply path is supplied from the outside and mixed with the chilled water to obtain chilled water of a predetermined temperature, Further, an ice making operation is performed by supplying the chilled water with a constant circulation flow rate to the heat exchanger. At the time of ice making, the water level of the ice storage tank constituting the ice storage type chilled water device gradually rises, and when the ice making operation is continued in this state, at the end of the ice storage, ice is discharged from the outlet of the heat exchanger. Ascending as ice bamboo shoots, the heat exchanger often freezes.
[0015]
The above-mentioned freezing phenomenon of the heat exchanger occurs when the amount of ice stored exceeds a certain limit.However, in an ice storage type chilled water device employing an external water supply system, the amount of ice stored is controlled by the ice making operation. It is not uniquely determined only by the amount of water stored in the ice storage tank before, but varies depending on the supply temperature of room-temperature water flowing through the external water supply passage and the ambient temperature of the refrigerator.
[0016]
More specifically, when the degree of supercooling, the circulation flow rate, the effective storage amount of the ice storage tank and the inlet temperature of the heat exchanger are fixed, and the relationship of heat storage is considered, the ice storage amount increases as the supply water temperature increases. I do. On the other hand, as the temperature of the refrigerator decreases, the cooling capacity increases. As a result, the degree of supercooling increases, and as a result, the ice storage amount increases as the atmospheric temperature of the refrigerator decreases. Therefore, at the end of ice storage, even if the water level in the ice storage tank is the same, the time until the heat exchanger reaches freezing may vary depending on the ice storage capacity at that time. That is, in the case of using the ice storage type chilled water device employing the external water supply method, the heat exchanger is frozen in a shorter time as the ice storage capacity is larger.
[0017]
Therefore, in the present invention, at the time of ice storage, until the water level of the ice storage tank reaches a preset reference water level, either the water supply temperature of the water flowing through the external water supply channel or the ambient temperature of the refrigerator. On the other hand, when both the water supply temperature and the ambient temperature of the refrigerator are detected, and then when the water level of the ice storage tank reaches the reference water level, an upper limit water level corresponding to the detected temperature is set, and the ice storage is performed. When the water level in the tank rises to the upper limit, the outlet temperature of the heat exchanger is adjusted to a temperature that does not cause supercooling.
[0018]
Here, in the present invention, the upper limit water level means that when a predetermined amount of a non-supercooled heat storage medium (for example, cold water of about 0.1 ° C.) is supplied to the ice storage tank when the water level is reached. This is the limit water level at which the freezing of the exchanger can be avoided.This water level depends on the conditions of the feedwater temperature and the ambient temperature of the refrigerator that affect the freezing speed of the heat exchanger. It is determined by selecting one of them. Further, in the present invention, the reference water level refers to a water level lower than the minimum water level among a plurality of water levels preset as the upper limit water level.
[0019]
Next, the operation control method of the present invention will be described in detail for each water level of the ice storage tank. First, until the water level of the ice storage tank reaches the reference water level, depending on the environment in which the ice storage tank is installed, either the water supply temperature of the water flowing through the external water supply channel or the ambient temperature of the refrigerator, or the water supply Detects both the temperature and the ambient temperature of the refrigerator. As an object to be detected, for example, when the refrigerator is installed indoors and the change in the outside air temperature is relatively small during the operation of the refrigerator, only the supply water temperature may be detected. In addition, when the refrigerator is installed outdoors and the change in the outside air temperature is relatively large, if only the ambient temperature of the refrigerator (outdoor temperature) or both the supply water temperature and the ambient temperature of the refrigerator are detected, Good.
[0020]
It is preferable that the above temperature is always detected using a temperature sensor. In addition, the reference water level and the upper limit water level described later are detected using the above-described water level detection means. As the water level detection means, a known water level detection device such as an electrode rod system, a float system, and a water pressure detection system may be employed. Can be. The temperature sensor and the water level detection means are both connected to the controller via a line.
[0021]
Next, when the water level in the ice storage tank reaches the reference water level, an upper limit water level corresponding to the detected temperature is set. Here, setting the upper limit water level means selecting one from a plurality of preset upper limit water levels. Specifically, when detecting only the feedwater temperature, when the detected feedwater temperature is higher than a preset temperature, a lower one of a plurality of preset upper limit water levels is selected, On the other hand, when the detected supply water temperature is lower than the preset temperature, a higher water level is selected from a plurality of preset upper limit water levels.
[0022]
Also, when only the ambient temperature of the refrigerator is detected, when the detected ambient temperature is lower than a preset temperature, a lower one of a plurality of preset upper limit water levels is selected, On the other hand, when the detected ambient temperature is higher than the preset temperature, the higher water level is selected from a plurality of preset upper limit water levels.
[0023]
In addition, when both the supply water temperature and the ambient temperature of the refrigerator are detected, the above methods are combined. Specifically, there are four cases depending on whether the detected feedwater temperature is lower than a preset temperature and whether the detected atmospheric temperature of the refrigerator is higher than a preset temperature. When the temperature is lower than the set temperature and the ambient temperature is higher than the set temperature, the highest water level (Ha) among the four upper limit water levels set in advance is selected, and (2) the water supply temperature is lower than the set temperature; When the ambient temperature is lower than the set temperature, the second highest water level (Hb) is selected from the four upper limit water levels set in advance. (3) When the feed water temperature is higher than the set temperature and the ambient temperature is higher than the set temperature, the third highest water level (Hc) is selected from among the four upper limit water levels set in advance, and When the temperature is higher than the set temperature and the ambient temperature is lower than the set temperature, the fourth highest water level (Hd) (that is, the lowest upper water level) is selected from among four preset upper water levels.
[0024]
Here, in the present invention, the upper limit water level may be Ha> Hb ≧ Hc ≧ Hd. For example, among the above four patterns, the freezing speed of the heat exchanger is the most in the case of the above (1) as compared with the other cases. Since it is late, the upper limit water level is divided into two types, the upper limit water level selected in the case of (1) and the common upper limit water level selected in any of (2), (3) and (4). Is also good.
[0025]
In the present invention, the detected temperature serving as an index when selecting the upper limit water level may be based on only the temperature detected when the water level of the ice storage tank has reached the reference water level, or may be based on the water level of the ice storage tank. Alternatively, the average temperature detected until the water reaches the reference water level may be used as the reference. The former is a suitable criterion when there is almost no temperature change during the ice storage operation, and the latter is a suitable criterion when the temperature changes drastically during the ice storage operation.
[0026]
Then, when the water level of the ice storage tank rises to the upper limit water level set above, the outlet temperature of the heat exchanger is adjusted to a temperature (for example, about 0.2 to 0.3 ° C.) at which supercooling does not occur. Specifically, using the temperature adjusting means provided in the external water supply passage, the normal temperature water and cold water flowing through the water supply passage are mixed to form cold water at a temperature slightly higher than the above temperature, and this is used as a heat exchanger. By supplying to the inlet, the outlet temperature of the heat exchanger is adjusted to a temperature that does not cause supercooling. This temperature adjustment is continued until the water level in the ice storage tank reaches the final water level, and the ice making operation is terminated. Here, examples of the temperature control method by the temperature control means include a method using a flow rate control valve (for example, a motor valve, a proportional control valve), a method by adjusting a flow rate of room temperature water by adjusting a valve opening, and an electric heater. A method of directly adjusting the temperature of normal-temperature water using a heating means may be used.
[0027]
According to the operation control method described above, after the water level in the ice storage tank reaches the upper limit water level, the heat storage medium (water) in a non-supercooled state is supplied to the ice storage tank in the minimum necessary amount, and the heat exchanger The ice storage step ends without freezing of the ice. Therefore, according to the present invention, it is possible to improve the ice storage amount (rate) and to shorten the ice storage time and save energy as compared with the related art.
[0028]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a first embodiment of an ice storage type chilled water device to which the operation control method of the present invention is applied.
[0029]
In FIG. 1, the ice storage type chiller is schematically composed of a refrigerator 11, a heat exchanger 21, and an ice storage tank 31, and the refrigerator 11 and the heat exchanger 21 are connected to a refrigerant supply path 12 and a refrigerant return path, respectively. 13 to form a refrigerant circuit as a whole. Further, the ice storage tank 31, the first temperature sensor 35, the pump 34, and the heat exchanger 21 are sequentially connected by a water supply path 32, and the heat exchanger 21 and the ice storage tank 31 are connected by a water return path 33. As a whole, it constitutes a water circulation path. An external water supply channel 41 for supplying room temperature water from outside is connected between the first temperature sensor 35 provided in the water supply channel 32 and the ice storage tank 31. A second temperature sensor 42 and a flow control valve 43 are connected to the external water supply passage 41 toward the water supply passage 32. Here, the heat exchanger 21 uses the same type of heat exchanger as in FIG. 7 described above.
[0030]
In the ice storage tank 31, an electrode rod type water level detecting device 36 is provided as water level detecting means. The water level detection device 36 is composed of five electrode rods L, S, H1, H2, and H, and the lower ends of the electrode rods are respectively set to a lower limit water level (L), a reference water level (S), It is detected as a first upper limit water level (H1), a second upper limit water level (H2), and a final water level (H). The first temperature sensor 35, the second temperature sensor 42, the flow control valve 43, and the water level detection device 36 are connected to a controller 51 via signal lines.
[0031]
Next, an ice making operation using the ice storage type chilled water device having the above configuration will be described with reference to FIG. First, after water as a heat storage medium is filled up to the lower limit water level (L) of the ice storage tank, the refrigerator 11 is started, and the refrigerant is supplied to the heat exchanger 21 to be circulated, and the pump 34 is started. The water in the ice storage tank 31 is supplied to the heat exchanger 21 via a water supply path 32. Then, the supercooled water in the supercooled state by heat exchange is returned to the ice storage tank through the water return path 33, and further collides with the water surface, whereby the supercooled state is released to generate slurry ice, This starts ice making (step S1).
[0032]
After a while, the temperature of the cold water flowing through the water supply passage 32 decreases. In this case, the flow control valve 43 provided in the external water supply passage 41 is provided based on the temperature condition detected by the first temperature sensor 35. Of the cold water flowing through the water supply passage 32 is supplied at room temperature in an amount corresponding to the temperature of the cold water flowing through the water supply path 32, and mixed with the cold water to obtain cold water at a predetermined temperature. In parallel with this, the supply temperature of room temperature water flowing through the external water supply channel 41 is constantly detected using the second temperature sensor 42.
[0033]
When the ice making progresses and the water level of the ice storage tank 31 reaches the reference water level (S), it is determined whether or not the water supply temperature is lower than 20 ° C. (step S2), and according to the water supply temperature detected at this reference water level. The upper limit water level is set. Specifically, when the supply water temperature is lower than 20 ° C., the second upper limit water level (H2) is selected (step S3). On the other hand, when the supply water temperature is higher than 20 ° C., the first upper limit water level (H1) is set. Selected (step S4). When the water level of the ice storage tank 31 rises to the selected upper limit water level, the opening degree of the flow control valve 43 provided in the external water supply passage 41 is adjusted based on a signal from the first temperature sensor 35 to a predetermined level. By supplying the normal temperature water adjusted to the flow rate to the water supply path 32, cold water having a temperature (0.2 ° C.) that does not become supercooled at the outlet of the heat exchanger 21 is supplied (step S5). Then, it is determined whether or not the water level of the ice storage tank 31 has reached the final water level (H) (step S6), and when the water level has reached, the ice storage is terminated (step S7). As described above, according to the operation control method of the present embodiment, after the water level of the ice storage tank 31 reaches the upper limit water level, the heat storage medium (water) in the non-supercooled state enters the ice storage tank to a necessary minimum. The ice storage step is completed as supplied and without freezing of the heat exchanger.
[0034]
Next, a second embodiment of the present invention will be described with reference to FIG. In the embodiment shown in FIG. 3, instead of detecting the feed water temperature shown in FIG. 1, the ambient temperature of the condenser constituting the refrigerator (corresponding to the outside air temperature in this embodiment) is detected. The ambient temperature of the refrigerator is detected by using a third temperature sensor 14 installed near the refrigerator 11. The basic configuration of the ice storage type chilled water device applied to the present embodiment is basically the same as that of the first embodiment, and the difference is that in the first embodiment, the second temperature In contrast to the provision of the sensor 42 for detecting the supply water temperature, the present embodiment is characterized in that the third temperature sensor 14 is provided near the refrigerator 11 to detect the ambient temperature of the refrigerator 11. Further, in this embodiment, as a condition for setting the upper limit water level, when the reference water level (S) is reached, it is determined whether or not the ambient temperature of the refrigerator 11 is equal to or higher than 20 ° C. (step S8 in FIG. 4). When the ambient temperature is equal to or higher than 20 ° C., the second upper limit water level (H2) is selected (Step S3 in the same drawing). On the other hand, when the supply water temperature is lower than 20 ° C., the first upper limit water level (H1) is selected. (Step S4 in the figure). Hereinafter, in FIG. 4, processes denoted by the same reference numerals as those in FIG. 2 indicate the same processes, and description thereof will be omitted.
[0035]
Next, a third embodiment of the present invention will be described with reference to FIG. The embodiment shown in FIG. 5 detects both the supply water temperature and the ambient temperature of the refrigerator (corresponding to the outside air temperature in this embodiment). The operation control method of the ice storage type chilled water device according to the present embodiment is a combination of the first embodiment and the second embodiment (see FIG. 6). Specifically, when the water level in the ice storage tank 31 has reached the reference water level (S), first, it is determined whether or not the water supply temperature is lower than 20 ° C (step S2). If the water supply temperature is lower than 20 ° C., it is subsequently determined whether or not the ambient temperature is equal to or higher than 20 ° C. (step S8). If the ambient temperature is equal to or higher than 20 ° C., the second upper limit water level (H2) is selected (step S3). On the other hand, if any other determination result is obtained, the first upper limit water level (H1) is selected. (Step S4). Hereinafter, in FIG. 6, the processes denoted by the same reference numerals as those in FIGS. 2 and 4 indicate the same processes, and the description thereof will be omitted.
[0036]
【The invention's effect】
As described above, according to the operation control method of the ice storage type chilled water device according to the present invention, after the water level of the ice storage tank reaches the upper limit water level, the non-supercooled heat storage medium (water) is charged into the ice storage tank. ) Is supplied to the minimum required, the ice storage process is completed without freezing the heat exchanger, the amount of ice storage (rate) can be improved, and the ice storage time is shortened to save energy. Can be achieved.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a first embodiment of an ice storage type chilled water device to which an operation control method of the present invention is applied.
FIG. 2 is a flowchart showing an operation control method in the ice storage type chilled water device of FIG.
FIG. 3 is a schematic configuration diagram showing a second embodiment of the ice storage type chilled water device to which the operation control method of the present invention is applied.
FIG. 4 is a flowchart illustrating an operation control method in the ice storage type chilled water device of FIG. 3;
FIG. 5 is a schematic configuration diagram showing a third embodiment of an ice storage type chilled water device to which the operation control method of the present invention is applied.
FIG. 6 is a flowchart showing an operation control method in the ice storage type chilled water device of FIG.
FIG. 7 is a schematic configuration diagram showing a conventional ice storage type chilled water device.
[Explanation of symbols]
11 Refrigerator 12 Refrigerant supply path 13 Refrigerant return path 14 Third temperature sensor 21 Heat exchanger 21a Outer pipe 21b Inner pipe 31 Ice storage tank 32 Water supply path 33 Water return path 34 Pump 35 First temperature sensor 36 Water level detecting device 41 External water supply channel 42 Second temperature sensor 43 Flow control valve 51 Controller

Claims

A refrigerator, a heat exchanger that superheats the heat storage medium by exchanging heat with the refrigerant discharged from the refrigerator, and the heat storage medium is accommodated and generated by releasing the supercooling of the heat storage medium. An ice storage tank for storing ice, wherein a water supply path connecting the heat exchanger and the ice storage tank is provided with an external water supply path for supplying water from outside; In the operation control method,
At the time of ice storage, detecting a supply temperature of water flowing through the external water supply channel and / or an ambient temperature of the refrigerator,
Next, when the water level of the ice storage tank reaches a preset reference water level, an upper limit water level corresponding to the detected temperature is set, and when the water level of the ice storage tank rises to the upper limit water level, An operation control method for an ice storage type chilled water device, comprising adjusting an outlet temperature to a temperature that does not cause supercooling.

The method according to claim 1, wherein the upper limit water level is set based on a temperature detected when the water level in the ice storage tank reaches the reference water level. .

2. The method according to claim 1, wherein the upper limit water level is set based on an average temperature detected until the water level of the ice storage tank reaches the reference water level. .

A refrigerator, a heat exchanger that superheats the heat storage medium by exchanging heat with the refrigerant discharged from the refrigerator, and the heat storage medium is accommodated and generated by releasing the supercooling of the heat storage medium. An ice storage tank for storing ice, an external water supply path interposed between a water supply path connecting the heat exchanger and the ice storage tank to supply water from outside, and a water level detection provided in the ice storage tank Means,
At the time of ice storage, detecting a supply temperature of water flowing through the external water supply channel and / or an ambient temperature of the refrigerator,
Next, when the water level of the ice storage tank reaches a preset reference water level, an upper limit water level corresponding to the detected temperature is set, and when the water level of the ice storage tank rises to the upper limit water level, An ice storage type chilled water device comprising a control means for adjusting an outlet temperature to a temperature that does not cause supercooling.