JP2004176931A

JP2004176931A - Ice thermal storage refrigerating device with secondary carbon dioxide cooling medium

Info

Publication number: JP2004176931A
Application number: JP2002339914A
Authority: JP
Inventors: Yukinobu Ikemoto; 幸信池本
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-11-22
Filing date: 2002-11-22
Publication date: 2004-06-24
Anticipated expiration: 2022-11-22
Also published as: JP4043348B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ice thermal storage refrigerating device with a secondary carbon dioxide cooling medium, preventing excessive pressure rise in part of the device when the operation of part of the device is stopped. <P>SOLUTION: The device comprises a refrigerating machine system A, an ice thermal storage system B in which the secondary cooling medium heat-exchanged in the refrigerating machine system is introduced into an ice making heat exchanger 6 for thermal storage operation, a secondary carbon dioxide cooling medium cooling system C for cooling the secondary carbon dioxide cooling medium using cold water obtained by ice thermally stored in the ice thermal storage system, a load side cooling system D for cooling load side cold water using the secondary carbon dioxide cooling medium cooled by the cold water in the secondary carbon dioxide cooling medium cooling system, and a first pressure rise restricting part F for restricting pressure rise to a set value or higher in the load side cooling system. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、炭酸ガス２次冷媒氷蓄熱冷凍装置に関し、特に、冷却用に大量の冷水又はブラインを必要とし、夜間電力による氷蓄熱を利用する薬品工場、食品工場、化学工場などの冷凍装置として利用が可能な炭酸ガス２次冷媒氷蓄熱冷凍装置に関する。
【０００２】
【従来の技術】
（１）冷媒を直接製氷コイルで蒸発させる直膨式冷凍装置により、又は冷凍機によりブラインを冷却し、そのブラインを製氷コイルにブラインポンプで搬送する間接式冷凍装置により、夜間に氷蓄熱し、昼間に蓄熱された氷により得られる冷水を直接ポンプにより搬送する冷凍装置が実用化されている。
【０００３】
（２）夜間の氷蓄熱を昼間に冷却能力の一部に利用し、冷凍機を昼間にも運転して冷水を作り、冷却に利用する冷凍装置が実用化されている。
【０００４】
（３）製氷方法は、上述のアイスオンコイル式の他に過冷却水による方法もある。
【０００５】
【特許文献１】
特開平１１−３０５９９号公報
【特許文献２】
特開２００１−１９９４４号公報
【特許文献３】
特開２００２−４８４２２号公報
【特許文献４】
特開２００２−９７０１１号公報
【特許文献５】
特開平１１−１４１７２号公報
【０００６】
【発明が解決しようとする課題】
（１）直膨式氷蓄熱冷凍装置は、冷媒充填量を多く必要とする。特に地球温暖化に与える影響の大きいＨＦＣ冷媒を利用する場合や、毒性・可燃性のあるアンモニア冷媒を利用する場合には充填量を少なくすることが望まれる。
【０００７】
（２）ブラインによる間接式氷蓄熱の場合は、ブラインの熱伝導率が悪く、冷凍機の蒸発温度を低くしなければならず、消費電力を多く必要とする。また、ブラインの顕熱による冷却であるから搬送量を多く必要とし、搬送のためのポンプの消費電力を多く必要とする。この氷蓄熱運転中の冷凍機及びポンプの消費電力を少なくすることが望まれる。
【０００８】
（３）蓄熱された氷により得られる冷水をそのまま搬送する場合、顕熱のみによる冷却であるから搬送量が多く搬送動力を多く必要とする。また、大きい配管径も必要で配管距離が長い場合は配管コストもかさむ。冷水搬送動力の低減と冷水配管コストを低減することが望まれる。
【０００９】
（４）例えば昼間又は夜間などに、装置の一部の運転が停止される場合に、装置の一部の圧力が過度に高まることがないことが望まれている。
【００１０】
本発明の目的は、装置の一部の運転が停止される場合に、装置の一部の圧力が過度に高まることがない炭酸ガス２次冷媒氷蓄熱冷凍装置を提供することである。
本発明の他の目的は、装置の一部の圧力が過度に高まることがなく、冷媒充填量が少なくて済む炭酸ガス２次冷媒氷蓄熱冷凍装置を提供することである。
【００１１】
本発明の更に他の目的は、装置の一部の運転が停止される場合に、装置の一部の圧力が過度に高まることがなく、冷凍機の消費電力を抑えることができる炭酸ガス２次冷媒氷蓄熱冷凍装置を提供することである。
本発明の更に他の目的は、装置の一部の運転が停止される場合に、装置の一部の圧力が過度に高まることがなく、ポンプの消費電力を抑えることができる炭酸ガス２次冷媒氷蓄熱冷凍装置を提供することである。
【００１２】
本発明の更に他の目的は、装置の一部の運転が停止される場合に、装置の一部の圧力が過度に高まることがなく、冷水搬送動力を抑えることができる炭酸ガス２次冷媒氷蓄熱冷凍装置を提供することである。
本発明の更に他の目的は、装置の一部の運転が停止される場合に、装置の一部の圧力が過度に高まることがなく、配管コストを抑えることができる炭酸ガス２次冷媒氷蓄熱冷凍装置を提供することである。
【００１３】
【課題を解決するための手段】
以下に、［発明の実施の形態］で使用する番号・符号を用いて、［課題を解決するための手段］を説明する。これらの番号・符号は、［特許請求の範囲］の記載と［発明の実施の形態］の記載との対応関係を明らかにするために付加されたものであるが、［特許請求の範囲］に記載されている発明の技術的範囲の解釈に用いてはならない。
【００１４】
本発明の炭酸ガス２次冷媒氷蓄熱冷凍装置は、冷凍機系統（Ａ）と、前記冷凍機系統（Ａ）で熱交換された２次冷媒が製氷用熱交換器（６）に導入されて蓄熱が行われる氷蓄熱系統（Ｂ）と、前記氷蓄熱系統（Ｂ）で蓄熱された氷により得られた冷水により炭酸ガス２次冷媒を冷却する炭酸ガス２次冷媒冷却系統（Ｃ）と、前記炭酸ガス２次冷媒冷却系統（Ｃ）の前記冷水により冷却された前記炭酸ガス２次冷媒により負荷側冷水を冷却する負荷側冷却系統（Ｄ）と、前記負荷側冷却系統（Ｄ）の圧力が設定値以上になることを抑制する第１圧力上昇抑制部（Ｆ）とを備えている。
【００１５】
本発明の炭酸ガス２次冷媒氷蓄熱冷凍装置において、前記冷凍機系統（Ａ）で熱交換される前記２次冷媒は、炭酸ガス２次冷媒である。
【００１６】
本発明の炭酸ガス２次冷媒氷蓄熱冷凍装置において、前記負荷側冷却系統（Ｄ）は、前記冷水により冷却されて液化した前記炭酸ガス２次冷媒を溜める第１受液器（１１）を含み、前記氷蓄熱系統（Ｂ）は、前記冷凍機系統（Ａ）で前記熱交換されて液化した前記炭酸ガス２次冷媒を溜める第２受液器（７）を含み、前記第１圧力上昇抑制部（Ｆ）では、前記第１受液器（１１）内のガスが前記第２受液器（７）に移送されることにより、前記負荷側冷却系統（Ｄ）の圧力が前記設定値以上になることが抑制される。
【００１７】
本発明の炭酸ガス２次冷媒氷蓄熱冷凍装置において、前記第２受液器（７）に移送される前記第１受液器（１１）内のガスは、前記第１受液器（１１）内の炭酸ガス液が自己蒸発したものである。
【００１８】
本発明の炭酸ガス２次冷媒氷蓄熱冷凍装置は、冷凍機系統（Ａ）と、前記冷凍機系統（Ａ）で熱交換された炭酸ガス２次冷媒が製氷用熱交換器（６）に導入されて蓄熱が行われる氷蓄熱系統（Ｂ）と、前記氷蓄熱系統（Ｂ）で蓄熱された氷により得られた冷水により炭酸ガス２次冷媒を冷却する炭酸ガス２次冷媒冷却系統（Ｃ）と、前記炭酸ガス２次冷媒冷却系統（Ｃ）の前記冷水により冷却された前記炭酸ガス２次冷媒により負荷側冷水を冷却する負荷側冷却系統（Ｄ）と、前記氷蓄熱系統（Ｂ）の圧力が所定値以上になることを抑制する第２圧力上昇抑制部（Ｆ）とを備えている。
【００１９】
本発明の炭酸ガス２次冷媒氷蓄熱冷凍装置において、前記負荷側冷却系統（Ｄ）は、前記冷水により冷却されて液化した前記炭酸ガス２次冷媒を溜める第１受液器（１１）を含み、前記氷蓄熱系統（Ｂ）は、前記冷凍機系統（Ａ）で前記熱交換されて液化した前記炭酸ガス２次冷媒を溜める第２受液器（７）を含み、前記第２圧力上昇抑制部（Ｆ）は、補助圧縮機（１７）と水冷凝縮器（１８）とを含み、前記補助圧縮機（１７）は、前記第２受液器（７）内のガスを圧縮し、前記水冷凝縮器（１８）は、前記補助圧縮機（１７）により圧縮された前記ガスを前記冷水により凝縮させ、前記凝縮してなる炭酸ガス液は、前記第１受液器（１１）に移送される。
【００２０】
本発明の炭酸ガス２次冷媒氷蓄熱冷凍装置は、冷凍機系統（Ａ）と、前記冷凍機系統（Ａ）で熱交換された炭酸ガス２次冷媒が製氷用熱交換器（６）に導入されて蓄熱が行われる氷蓄熱系統（Ｂ）と、前記氷蓄熱系統（Ｂ）で蓄熱された氷により得られた冷水により炭酸ガス２次冷媒を冷却する炭酸ガス２次冷媒冷却系統（Ｃ）と、前記炭酸ガス２次冷媒冷却系統（Ｃ）の前記冷水により冷却された前記炭酸ガス２次冷媒により負荷側冷水を冷却する負荷側冷却系統（Ｄ）と、前記負荷側冷却系統（Ｄ）の圧力が設定値以上になることを抑制すると共に前記氷蓄熱系統（Ｂ）の圧力が所定値以上になることを抑制する圧力上昇抑制部（Ｆ）とを備えている。
【００２１】
本発明の炭酸ガス２次冷媒氷蓄熱冷凍装置において、前記負荷側冷却系統（Ｄ）は、前記冷水により冷却されて液化した前記炭酸ガス２次冷媒を溜める第１受液器（１１）を含み、前記氷蓄熱系統（Ｂ）は、前記冷凍機系統（Ａ）で前記熱交換されて液化した前記炭酸ガス２次冷媒を溜める第２受液器（７）を含み、前記圧力上昇抑制部（Ｆ）は、補助圧縮機（１７）と水冷凝縮器（１８）とを含み、前記圧力上昇抑制部（Ｆ）では、前記第１受液器（１１）内のガスが前記第２受液器（７）に移送されることにより、前記負荷側冷却系統（Ｄ）の圧力が前記設定値以上になることが抑制され、前記補助圧縮機（１７）は、前記第２受液器（７）内のガスを圧縮し、前記水冷凝縮器（１８）は、前記補助圧縮機（１７）により圧縮された前記ガスを前記冷水により凝縮させ、前記凝縮してなる炭酸ガス液が、前記第１受液器（１１）に移送されることにより、前記氷蓄熱系統（Ｂ）の圧力が前記所定値以上になることが抑制される。
【００２２】
本発明の炭酸ガス２次冷媒氷蓄熱冷凍装置において、前記冷凍機系統（Ａ）及び前記氷蓄熱系統（Ｂ）は、昼間、運転が停止される。
【００２３】
本発明の炭酸ガス２次冷媒氷蓄熱冷凍装置において、前記炭酸ガス２次冷媒冷却系統（Ｃ）及び前記負荷側冷却系統（Ｄ）は、夜間、運転が停止される。
【００２４】
（１）本発明は、製氷に炭酸ガス２次冷媒を利用することで冷凍機の冷媒充填量を減少させることができる。
【００２５】
（２）本発明では、間接式氷蓄熱方式において、ブラインの代わりに熱伝導率の良い炭酸ガスを利用することで、製氷コイル内の２次冷媒温度を高くすることができる。また、炭酸ガス２次冷媒の蒸発潜熱により冷却するため、コイル内温度を製氷に最適な温度とすることができ、冷凍機の蒸発温度を高くすることができるので氷蓄熱運転中の冷凍機の消費電力を少なくすることができる。
また、氷蓄熱回路の炭酸ガス２次冷媒の大きい潜熱を利用できるため循環量を少なくできるので搬送のための消費電力を大幅に低減することができる。
【００２６】
（３）本発明では、負荷側に顕熱を利用する多量の冷水を長配管で搬送する代わりに、大きい潜熱を利用できる少量の炭酸ガス２次冷媒を搬送するために、搬送動力を低減することができる。また、配管径を小径化できるので配管コストも低減することができる。
【００２７】
【発明の実施の形態】
添付図面を参照して、本発明の炭酸ガス２次冷媒氷蓄熱冷凍装置の一実施形態を説明する。
【００２８】
図１は、本実施形態に係る炭酸ガス２次冷媒氷蓄熱冷凍装置の系統図である。本実施形態の炭酸ガス２次冷媒氷蓄熱冷凍装置は、冷凍機系統Ａと、氷蓄熱系統Ｂと、炭酸ガス２次冷媒冷却系統Ｃと、負荷側冷却系統Ｄと、負荷冷水系統Ｅと、補助冷凍機系統Ｆとを備えている。
【００２９】
冷凍機系統Ａは、炭酸ガス２次冷媒を冷却する系統である。冷凍機系統Ａは、圧縮機１と、凝縮器２と、膨張弁３と、カスケード蒸発器４により構成される。カスケード蒸発器４は、氷蓄熱系統Ｂの炭酸ガス２次冷媒の凝縮器を兼ねている。
【００３０】
氷蓄熱系統Ｂは、炭酸ガス２次冷媒で製氷する系統である。氷蓄熱系統Ｂは、蓄熱槽５と、蓄熱槽５内に配置される製氷用熱交換器６と、製氷用熱交換器６の出口から戻る液とガスの２相流炭酸ガスのガスを液化するカスケード蒸発器４と、その液化された炭酸ガス液を溜める受液器７と、その炭酸ガス液を製氷用熱交換器６へ搬送する炭酸ガスポンプ８を備えている。
【００３１】
炭酸ガス２次冷媒冷却系統Ｃは、蓄熱された氷により得られる冷水で炭酸ガス２次冷媒を冷却する系統である。炭酸ガス２次冷媒冷却系統Ｃは、冷水ポンプ９と、水冷凝縮器１０を備えている。
【００３２】
負荷側冷却系統Ｄは、炭酸ガス２次冷媒により負荷冷水系統Ｅの負荷側冷水を冷却する系統である。負荷側冷却系統Ｄは、水冷凝縮器１０と、水冷凝縮器１０で液化した炭酸ガス液を溜める受液器１１と、その炭酸ガス液を搬送する炭酸ガスポンプ１２と、その搬送された炭酸ガス液により負荷冷水系統Ｅの負荷側冷水を冷却する熱交換器１３を備えている。
【００３３】
負荷冷水系統Ｅは、負荷を冷水で冷却する系統である。負荷冷水系統Ｅは、熱交換器１３と、熱交換器１３で得られた冷水を負荷側に搬送する冷水ポンプ１４と、負荷側熱交換器１５とを備えている。
【００３４】
補助冷凍機系統Ｆは、昼間の作業時間帯以外の夜間などの時間帯に、負荷側冷却系統Ｄが停止している間に、負荷側冷却系統Ｄの圧力が上昇したときに電磁弁１６ａを開いて受液器１１内のガスを低圧側の受液器７に移送させ、蒸発による自己冷却により設計圧力以上に圧力が上昇することを防ぐ回路を有している。
【００３５】
また、補助冷凍機系統Ｆでは、作業時間帯である昼間などの時間帯に、冷凍機系統Ａが停止している間に、氷蓄熱系統Ｂの圧力が設計圧力以上に上昇したときに電磁弁１６ｂを開いて受液器７の上部から炭酸ガスを補助圧縮機１７により吸入し、補助圧縮機１７から吐出したガスを水冷凝縮器１８にて冷水ポンプ１９により搬送される冷水で冷却する。その凝縮した炭酸ガス液は、受液器１１に入る。
【００３６】
本実施形態では、間接式冷凍装置を採用し、製氷に炭酸ガス２次冷媒を利用することで、冷凍機系統Ａの冷媒充填量を減少させることができる。
【００３７】
氷蓄熱系統Ｂでは、間接式氷蓄熱方式において、ブラインの代わりに熱伝達率の良い炭酸ガスを利用することで、製氷コイル（製氷用熱交換器６）内の２次冷媒温度（製氷用熱交換器６に導入される炭酸ガス液の温度）を高くすることができる。また、製氷用熱交換器６での炭酸ガス２次冷媒の蒸発潜熱により蓄熱槽５内の冷水を冷却するため、製氷用熱交換器６のコイル内温度を製氷に最適な温度とすることができ、冷凍機系統Ａのカスケード蒸発器４での蒸発温度を高くすることができる（図２の運転条件参照）ので氷蓄熱系統Ｂの運転中の冷凍機系統Ａの消費電力を少なくすることができる。
【００３８】
また、氷蓄熱系統Ｂの炭酸ガス２次冷媒の大きい潜熱を利用でき、製氷用熱交換器６への循環量を少なくできるので、搬送のための炭酸ガスポンプ８の消費電力を大幅に低減させることができる。
【００３９】
さらに、本実施形態では、顕熱を利用する多量の冷水を負荷側まで長い配管内を搬送する代わりに、大きい潜熱を利用できる少量の炭酸ガス２次冷媒（負荷側冷却系統Ｄの炭酸ガス２次冷媒）を搬送するために、搬送動力を低減させることができる。また、負荷側冷却系統Ｄの配管の径を小径化できるので配管コストも低減させることができる。
【００４０】
本実施形態の炭酸ガス２次冷媒氷蓄熱冷凍装置では、夜間の電力を用いた氷蓄熱のために氷蓄熱系統Ｂにおいて炭酸ガス２次冷媒が用いられ、その夜間の氷蓄熱を用いて昼間、負荷冷水系統Ｅにおいて負荷冷却が行われる。
【００４１】
氷蓄熱系統Ｂの炭酸ガス２次冷媒は、夜間、冷凍機系統Ａにより冷却されることで、蓄熱槽５において氷蓄熱が行われる。昼間は、冷凍機系統Ａが停止され、蓄熱槽５において夜間蓄熱された氷により得られる冷水により、負荷側冷却系統Ｄの炭酸ガス２次冷媒が冷却される。その冷却された負荷側冷却系統Ｄの炭酸ガス２次冷媒により、負荷が直接的または間接的に冷却される。
【００４２】
氷蓄熱系統Ｂの炭酸ガス２次冷媒は、夜間、冷凍機系統Ａにより冷却され氷蓄熱のために利用される。負荷側冷却系統Ｄの炭酸ガス２次冷媒は、昼間、炭酸ガス２次冷媒冷却系統Ｃにより要求される温度に冷却され、負荷を直接又は間接に冷却するために利用される。
【００４３】
昼間の作業時間以外の夜間などの時間帯は、負荷側冷却系統Ｄの炭酸ガス２次冷媒回路が停止している。その停止している間に、負荷側冷却系統Ｄの炭酸ガス２次冷媒の圧力が設定値以上に上昇することを防ぐ必要がある。そのために、負荷側冷却系統Ｄの受液器１１のガスを低圧の氷蓄熱系統Ｂの受液器７へ連通させ、受液器１１の炭酸ガス液を自己蒸発させて温度上昇を防ぎ、設計圧力以上に圧力が上昇しないようにする。
【００４４】
一方、昼間の作業時間帯は、氷蓄熱系統Ｂの炭酸ガス２次冷媒回路が停止している。その停止している間に、氷蓄熱系統Ｂの炭酸ガス２次冷媒の圧力が所定値以上に上昇することを防ぐ必要がある。そのために、氷蓄熱系統Ｂの受液器７のガスを補助圧縮機１７により吸込み圧縮した後、水冷凝縮器１８においてポンプ１９により送出される蓄熱された氷による冷水で凝縮させ、その後、高圧側の受液器１１へ移送する補助冷却回路Ｆが設けられている。
【００４５】
図２は、本実施形態による圧縮機およびポンプの消費電力を従来のブライン方式と比較したものである。運転条件は、図２に示す以下の通りである。冷凍機系統の冷媒は、本実施形態及び従来ブライン方式共に、ＨＦＣ系冷媒であるＲ４０４Ａを用いる。本実施形態のカスケード蒸発器４での凝縮／蒸発温度は、５０／−７℃であり、従来ブライン方式では５０／−１５℃である。本実施形態の氷蓄熱系統Ｂの炭酸ガス２次冷媒の温度は、−７℃である。従来ブライン方式のブラインの温度は、−１０℃→−５℃である。負荷は、本実施形態及び従来ブライン方式共に、１００ＫＷである。これらの運転条件の下では、図２に示すように、従来ブライン方式に比べて本実施形態は、圧縮機およびポンプの消費電力の合計で、２３％低減することができた。
【００４６】
図３は、本実施形態による負荷側冷却系統Ｄの配管工事費と保冷工事費の合計を対応する従来の装置（冷水循環方式）と比較したものである。条件は、図３に示す以下の通りである。配管長（片道）は、本実施形態及び従来冷水循環方式共に、５０ｍである。配管材料は、本実施形態では圧力配管用炭素鋼々管であり、従来冷水循環方式ではステンレス鋼々管である。配管寸法は、本実施形態では２５Ａであり、従来冷水循環方式では６０Ｓｕである。負荷は、本実施形態及び従来冷水循環方式共に、１００ＫＷである。流体の温度は、本実施形態では２℃であり、従来冷水循環方式では３℃である。これらの条件の下では、図３に示すように、従来冷水循環方式に比べて本実施形態は、配管工事費と保冷工事費の合計で、４５％低減することができた。
【００４７】
以上のように構成された本実施形態の炭酸ガス２次冷媒氷蓄熱冷凍装置は、従来の直膨式氷蓄熱装置に比べて冷媒充填量を大幅に減少することができ、また、ブライン式氷蓄熱装置に比べて図２に示すように消費電力を減少することができることで地球環境負荷の少ない冷凍装置を提供することができる。更に、図３に示す通り、負荷側冷却系統Ｄの配管寸法を細径化できるため、その配管工事費と断熱工事費を従来の装置に比べて低減することができる。
【００４８】
【発明の効果】
本発明の炭酸ガス２次冷媒氷蓄熱冷凍装置によれば、装置の一部の運転が停止された場合にも圧力が過度に高まることを抑制することができる。
【図面の簡単な説明】
【図１】図１は、本発明の炭酸ガス２次冷媒氷蓄熱冷凍装置の一実施形態の構成を示す図である。
【図２】図２は、本発明の炭酸ガス２次冷媒氷蓄熱冷凍装置の一実施形態と従来のブライン方式の消費電力を比較した図である。
【図３】図３は、本発明の炭酸ガス２次冷媒氷蓄熱冷凍装置の一実施形態と従来の冷水循環方式の配管・保冷工事費を比較した図である。
【符号の説明】
Ａ冷凍機系統
Ｂ氷蓄熱系統
Ｃ炭酸ガス２次冷媒冷却系統
Ｄ負荷側冷却系統
Ｅ負荷冷水系統
Ｆ補助冷凍機系統
１圧縮機
２凝縮器
３膨張弁
４カスケード蒸発器
５蓄熱槽
６製氷用熱交換器
７受液器
８炭酸ガスポンプ
９冷水ポンプ
１０水冷凝縮器
１１受液器
１２炭酸ガスポンプ
１３熱交換器
１４冷水ポンプ
１５負荷側熱交換器
１６ａ、１６ｂ電磁弁
１７補助圧縮機
１８水冷凝縮器
１９ポンプ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a carbon dioxide gas secondary refrigerant ice heat storage refrigeration apparatus, and particularly requires a large amount of cold water or brine for cooling, and is used as a refrigeration apparatus such as a drug factory, a food factory, and a chemical factory that uses ice heat storage by nighttime electric power. The present invention relates to a carbon dioxide secondary refrigerant ice storage refrigeration apparatus that can be used.
[0002]
[Prior art]
(1) The ice is stored at night by a direct expansion type refrigeration unit that directly evaporates the refrigerant with an ice making coil, or by an indirect refrigeration unit that cools the brine by a refrigerator and conveys the brine to the ice making coil by a brine pump, A refrigeration apparatus that directly conveys cold water obtained by ice stored in the daytime by a pump has been put to practical use.
[0003]
(2) A refrigerating apparatus has been put to practical use in which ice heat storage at night is used as part of a cooling capacity in the daytime and a refrigerator is operated during the daytime to produce cold water for cooling.
[0004]
(3) As an ice making method, there is a method using supercooled water in addition to the above-mentioned ice-on-coil method.
[0005]
[Patent Document 1]
JP-A-11-30599 [Patent Document 2]
Japanese Patent Application Laid-Open No. 2001-19944 [Patent Document 3]
Japanese Patent Application Laid-Open No. 2002-48422 [Patent Document 4]
JP-A-2002-97011 [Patent Document 5]
JP-A-11-14172
[Problems to be solved by the invention]
(1) The direct expansion type ice heat storage refrigeration apparatus requires a large amount of refrigerant to be charged. In particular, when using an HFC refrigerant having a large effect on global warming or when using a toxic / flammable ammonia refrigerant, it is desired to reduce the filling amount.
[0007]
(2) In the case of indirect ice heat storage using brine, the thermal conductivity of the brine is poor, and the evaporating temperature of the refrigerator must be lowered, requiring a large amount of power consumption. Further, since the cooling is performed by the sensible heat of the brine, a large transport amount is required, and a large power consumption of a pump for transport is required. It is desired to reduce the power consumption of the refrigerator and the pump during the ice heat storage operation.
[0008]
(3) When the cold water obtained by the stored ice is transported as it is, cooling is performed only by sensible heat, so that the transport amount is large and the transport power is large. Also, a large piping diameter is required, and if the piping distance is long, piping costs are also increased. It is desired to reduce the chilled water conveyance power and the chilled water piping cost.
[0009]
(4) It is desired that when the operation of a part of the apparatus is stopped, for example, during the daytime or at night, the pressure of the part of the apparatus does not excessively increase.
[0010]
An object of the present invention is to provide a carbon dioxide secondary refrigerant ice heat storage refrigeration apparatus in which the pressure of a part of the apparatus does not excessively increase when the operation of the part of the apparatus is stopped.
Another object of the present invention is to provide a carbon dioxide secondary refrigerant ice heat storage refrigeration apparatus that does not require excessively high pressure in a part of the apparatus and requires only a small amount of refrigerant.
[0011]
Still another object of the present invention is to provide a secondary carbon dioxide gas capable of suppressing the power consumption of a refrigerator without excessively increasing the pressure of a part of the device when the operation of a part of the device is stopped. An object of the present invention is to provide a refrigerant ice heat storage refrigeration apparatus.
Still another object of the present invention is to provide a carbon dioxide secondary refrigerant that can suppress the power consumption of a pump without excessively increasing the pressure of a part of the device when the operation of a part of the device is stopped. An object of the present invention is to provide an ice storage refrigerator.
[0012]
Still another object of the present invention is to provide a carbon dioxide secondary refrigerant ice that can suppress the chilled water conveyance power without excessively increasing the pressure of a part of the device when the operation of the device is partially stopped. It is to provide a heat storage refrigeration apparatus.
Still another object of the present invention is to provide a secondary storage device for storing carbon dioxide secondary refrigerant ice in which when the operation of a part of the apparatus is stopped, the pressure of the part of the apparatus is not excessively increased and the piping cost can be reduced. It is to provide a refrigeration device.
[0013]
[Means for Solving the Problems]
Hereinafter, [Means for Solving the Problems] will be described using the numbers and symbols used in [Embodiments of the Invention]. These numbers and symbols are added to clarify the correspondence between the description of [Claims] and the description of [Embodiments of the Invention]. It should not be used to interpret the technical scope of the described invention.
[0014]
In the carbon dioxide gas secondary refrigerant ice heat storage refrigeration apparatus of the present invention, a refrigerator system (A) and a secondary refrigerant heat-exchanged in the refrigerator system (A) are introduced into an ice making heat exchanger (6). An ice heat storage system (B) in which heat is stored, a carbon dioxide gas secondary refrigerant cooling system (C) for cooling the carbon dioxide gas secondary refrigerant with cold water obtained by ice stored in the ice heat storage system (B), A load side cooling system (D) for cooling load side cold water by the carbon dioxide gas secondary refrigerant cooled by the cold water of the carbon dioxide gas secondary refrigerant cooling system (C); and a pressure of the load side cooling system (D). And a first pressure rise suppressing section (F) for suppressing the pressure from becoming equal to or more than a set value.
[0015]
In the carbon dioxide gas secondary refrigerant ice storage refrigeration apparatus of the present invention, the secondary refrigerant that is heat-exchanged in the refrigerator system (A) is a carbon dioxide gas secondary refrigerant.
[0016]
In the carbon dioxide secondary refrigerant ice heat storage refrigeration apparatus of the present invention, the load side cooling system (D) includes a first liquid receiver (11) for storing the carbon dioxide secondary refrigerant cooled and liquefied by the cold water. The ice heat storage system (B) includes a second liquid receiver (7) that stores the carbon dioxide secondary refrigerant that has been heat-exchanged and liquefied in the refrigerator system (A), and that the first pressure rise suppression is performed. In the section (F), the gas in the first liquid receiver (11) is transferred to the second liquid receiver (7) so that the pressure of the load-side cooling system (D) is equal to or higher than the set value. Is suppressed.
[0017]
In the carbon dioxide secondary refrigerant ice heat storage refrigeration apparatus of the present invention, the gas in the first liquid receiver (11) transferred to the second liquid receiver (7) is the first liquid receiver (11). The carbon dioxide gas inside is self-evaporated.
[0018]
According to the carbon dioxide secondary refrigerant ice heat storage refrigeration apparatus of the present invention, the refrigerator system (A) and the carbon dioxide secondary refrigerant heat-exchanged in the refrigerator system (A) are introduced into the ice making heat exchanger (6). An ice heat storage system (B) in which heat is stored by being cooled, and a carbon dioxide gas secondary refrigerant cooling system (C) that cools the carbon dioxide gas secondary refrigerant with cold water obtained by ice stored in the ice heat storage system (B). A load-side cooling system (D) for cooling load-side cold water with the carbon dioxide secondary refrigerant cooled by the cold water of the carbon dioxide gas secondary refrigerant cooling system (C), and an ice heat storage system (B). A second pressure rise suppression unit (F) for suppressing the pressure from being equal to or higher than a predetermined value.
[0019]
In the carbon dioxide secondary refrigerant ice heat storage refrigeration apparatus of the present invention, the load side cooling system (D) includes a first liquid receiver (11) for storing the carbon dioxide secondary refrigerant cooled and liquefied by the cold water. The ice heat storage system (B) includes a second liquid receiver (7) for storing the carbon dioxide secondary refrigerant liquefied by the heat exchange in the refrigerator system (A), and the second pressure rise suppression. The section (F) includes an auxiliary compressor (17) and a water-cooled condenser (18), and the auxiliary compressor (17) compresses gas in the second liquid receiver (7), and The condenser (18) condenses the gas compressed by the auxiliary compressor (17) with the cold water, and the condensed carbon dioxide liquid is transferred to the first liquid receiver (11). .
[0020]
According to the carbon dioxide secondary refrigerant ice heat storage refrigeration apparatus of the present invention, the refrigerator system (A) and the carbon dioxide secondary refrigerant heat-exchanged in the refrigerator system (A) are introduced into the ice making heat exchanger (6). An ice heat storage system (B) in which heat is stored by being cooled, and a carbon dioxide gas secondary refrigerant cooling system (C) that cools the carbon dioxide gas secondary refrigerant with cold water obtained by ice stored in the ice heat storage system (B). A load side cooling system (D) for cooling load side cold water by the carbon dioxide gas secondary refrigerant cooled by the cold water of the carbon dioxide gas secondary refrigerant cooling system (C), and the load side cooling system (D) And a pressure rise suppressing portion (F) for suppressing the pressure of the ice heat storage system (B) from becoming equal to or more than a predetermined value while suppressing the pressure of the ice heat storage system (B) from becoming equal to or more than a set value.
[0021]
In the carbon dioxide secondary refrigerant ice heat storage refrigeration apparatus of the present invention, the load side cooling system (D) includes a first liquid receiver (11) for storing the carbon dioxide secondary refrigerant cooled and liquefied by the cold water. The ice heat storage system (B) includes a second liquid receiver (7) that stores the carbon dioxide secondary refrigerant that has been heat-exchanged and liquefied in the refrigerator system (A), and the pressure rise suppression unit ( F) includes an auxiliary compressor (17) and a water-cooled condenser (18), and in the pressure rise suppression section (F), the gas in the first liquid receiver (11) is changed to the second liquid receiver. By being transferred to (7), the pressure of the load side cooling system (D) is suppressed from becoming equal to or higher than the set value, and the auxiliary compressor (17) is connected to the second liquid receiver (7). The water-cooled condenser (18) is compressed by the auxiliary compressor (17). The condensed carbon dioxide gas is condensed by the cold water, and the condensed carbon dioxide gas liquid is transferred to the first liquid receiver (11), so that the pressure of the ice heat storage system (B) becomes equal to or higher than the predetermined value. Is suppressed.
[0022]
In the carbon dioxide secondary refrigerant ice heat storage refrigeration system of the present invention, the refrigerator system (A) and the ice heat storage system (B) are stopped during daytime operation.
[0023]
In the carbon dioxide secondary refrigerant ice heat storage refrigeration apparatus of the present invention, the operation of the carbon dioxide secondary refrigerant cooling system (C) and the load-side cooling system (D) is stopped at night.
[0024]
(1) According to the present invention, the amount of refrigerant charged in the refrigerator can be reduced by using the carbon dioxide secondary refrigerant for ice making.
[0025]
(2) In the present invention, in the indirect ice heat storage method, the temperature of the secondary refrigerant in the ice making coil can be increased by using carbon dioxide having good thermal conductivity instead of brine. Further, since cooling is performed by the latent heat of vaporization of the carbon dioxide secondary refrigerant, the temperature in the coil can be set to an optimum temperature for ice making, and the evaporation temperature of the refrigerator can be increased. Power consumption can be reduced.
Further, since the large latent heat of the carbon dioxide secondary refrigerant in the ice heat storage circuit can be used, the amount of circulation can be reduced, so that the power consumption for transportation can be significantly reduced.
[0026]
(3) In the present invention, instead of transporting a large amount of chilled water using sensible heat to the load side by a long pipe, a small amount of carbon dioxide secondary refrigerant capable of using large latent heat is transported, so that the transport power is reduced. be able to. Further, since the pipe diameter can be reduced, the pipe cost can be reduced.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
With reference to the attached drawings, an embodiment of a carbon dioxide secondary refrigerant ice heat storage refrigeration apparatus of the present invention will be described.
[0028]
FIG. 1 is a system diagram of a carbon dioxide secondary refrigerant ice heat storage refrigeration apparatus according to the present embodiment. The carbon dioxide gas secondary refrigerant ice heat storage refrigeration apparatus of this embodiment includes a refrigerator system A, an ice heat storage system B, a carbon dioxide gas secondary refrigerant cooling system C, a load side cooling system D, a load chilled water system E, And an auxiliary refrigerator system F.
[0029]
The refrigerator system A is a system for cooling the carbon dioxide secondary refrigerant. The refrigerator system A includes a compressor 1, a condenser 2, an expansion valve 3, and a cascade evaporator 4. The cascade evaporator 4 also serves as a condenser for the secondary refrigerant of carbon dioxide in the ice heat storage system B.
[0030]
The ice heat storage system B is a system that makes ice with a carbon dioxide secondary refrigerant. The ice heat storage system B liquefies a heat storage tank 5, a heat exchanger 6 for ice making arranged in the heat storage tank 5, and a two-phase flow carbon dioxide gas of a liquid and a gas returning from an outlet of the heat exchanger 6 for ice making. A cascade evaporator 4, a liquid receiver 7 for storing the liquefied carbon dioxide gas liquid, and a carbon dioxide pump 8 for transporting the carbon dioxide gas to the ice making heat exchanger 6.
[0031]
The carbon dioxide secondary refrigerant cooling system C is a system that cools the carbon dioxide secondary refrigerant with cold water obtained by stored ice. The carbon dioxide secondary refrigerant cooling system C includes a chilled water pump 9 and a water-cooled condenser 10.
[0032]
The load side cooling system D is a system that cools the load side chilled water of the load chilled water system E with the carbon dioxide secondary refrigerant. The load-side cooling system D includes a water-cooled condenser 10, a receiver 11 for storing the carbon dioxide gas liquefied by the water-cooled condenser 10, a carbon dioxide pump 12 for transporting the carbon dioxide gas, and a And a heat exchanger 13 for cooling the load side chilled water of the load chilled water system E.
[0033]
The load chilled water system E is a system that cools the load with chilled water. The load chilled water system E includes a heat exchanger 13, a chilled water pump 14 that conveys the chilled water obtained by the heat exchanger 13 to the load side, and a load side heat exchanger 15.
[0034]
The auxiliary refrigerator system F activates the solenoid valve 16a when the pressure of the load-side cooling system D rises while the load-side cooling system D is stopped during a time period such as nighttime other than the daytime working time period. It has a circuit that opens to transfer the gas in the receiver 11 to the receiver 7 on the low pressure side and prevents the pressure from rising above the design pressure due to self-cooling by evaporation.
[0035]
Further, in the auxiliary refrigerator system F, when the pressure of the ice heat storage system B rises to a design pressure or more while the refrigerator system A is stopped during a time period such as daytime, which is a working time period, the solenoid valve is operated. By opening 16b, carbon dioxide gas is sucked in from the upper part of the liquid receiver 7 by the auxiliary compressor 17, and the gas discharged from the auxiliary compressor 17 is cooled by the water-cooled condenser 18 with cold water conveyed by the cold water pump 19. The condensed carbon dioxide gas enters the receiver 11.
[0036]
In the present embodiment, the refrigerant filling amount of the refrigerator system A can be reduced by employing an indirect refrigeration device and using a carbon dioxide secondary refrigerant for ice making.
[0037]
In the ice heat storage system B, in the indirect ice heat storage method, by using carbon dioxide having a high heat transfer rate instead of brine, the secondary refrigerant temperature (heat for ice making) in the ice making coil (ice heat exchanger 6) is used. The temperature of the carbon dioxide gas introduced into the exchanger 6) can be increased. Further, in order to cool the cold water in the heat storage tank 5 by the latent heat of evaporation of the carbon dioxide gas secondary refrigerant in the ice making heat exchanger 6, the temperature inside the coil of the ice making heat exchanger 6 may be set to an optimum temperature for ice making. As a result, the evaporation temperature in the cascade evaporator 4 of the refrigerator system A can be increased (see the operating conditions in FIG. 2), so that the power consumption of the refrigerator system A during the operation of the ice storage system B can be reduced. it can.
[0038]
Further, since the large latent heat of the secondary carbon dioxide gas refrigerant of the ice heat storage system B can be used and the amount of circulation to the ice making heat exchanger 6 can be reduced, the power consumption of the carbon dioxide gas pump 8 for transportation can be significantly reduced. Can be.
[0039]
Further, in the present embodiment, instead of transporting a large amount of cold water using sensible heat to the load side through a long pipe, a small amount of carbon dioxide secondary refrigerant (carbon dioxide 2 of the load side cooling system D) capable of using large latent heat is used. In order to transport the next refrigerant, the transport power can be reduced. Further, since the diameter of the pipe of the load side cooling system D can be reduced, the cost of the pipe can be reduced.
[0040]
In the carbon dioxide gas secondary refrigerant ice heat storage refrigeration apparatus of the present embodiment, the carbon dioxide gas secondary refrigerant is used in the ice heat storage system B for ice heat storage using electric power at night, and during the daytime using the ice heat storage at night, Load cooling is performed in the load chilled water system E.
[0041]
The carbon dioxide secondary refrigerant in the ice heat storage system B is cooled by the refrigerator system A at night, so that ice heat is stored in the heat storage tank 5. During the daytime, the refrigerator system A is stopped, and the carbon dioxide secondary refrigerant in the load side cooling system D is cooled by cold water obtained by ice stored in the heat storage tank 5 at night. The load is cooled directly or indirectly by the cooled secondary carbon dioxide gas in the load side cooling system D.
[0042]
The secondary carbon dioxide gas refrigerant in the ice heat storage system B is cooled by the refrigerator system A at night to be used for ice heat storage. The carbon dioxide secondary refrigerant in the load side cooling system D is cooled to a temperature required by the carbon dioxide secondary refrigerant cooling system C during the daytime, and is used for directly or indirectly cooling the load.
[0043]
During a time zone such as nighttime other than the daytime working hours, the carbon dioxide secondary refrigerant circuit of the load side cooling system D is stopped. During the stop, it is necessary to prevent the pressure of the carbon dioxide secondary refrigerant in the load side cooling system D from rising above a set value. For this purpose, the gas in the receiver 11 of the load-side cooling system D is communicated with the receiver 7 of the low-pressure ice heat storage system B, and the carbon dioxide gas in the receiver 11 is self-evaporated to prevent the temperature from rising. Ensure that the pressure does not rise above the pressure.
[0044]
On the other hand, in the daytime working hours, the secondary carbon dioxide gas circuit of the ice heat storage system B is stopped. During the stop, it is necessary to prevent the pressure of the carbon dioxide secondary refrigerant in the ice heat storage system B from rising to a predetermined value or more. For this purpose, the gas in the receiver 7 of the ice heat storage system B is sucked and compressed by the auxiliary compressor 17 and then condensed with cold water of the stored ice sent out by the pump 19 in the water-cooled condenser 18, and then the high-pressure side An auxiliary cooling circuit F for transferring the liquid to the liquid receiver 11 is provided.
[0045]
FIG. 2 compares the power consumption of the compressor and the pump according to the present embodiment with that of the conventional brine system. The operating conditions are as shown in FIG. The refrigerant of the refrigerator system uses R404A, which is an HFC-based refrigerant, in both the present embodiment and the conventional brine system. The condensation / evaporation temperature in the cascade evaporator 4 of the present embodiment is 50 / -7 ° C, and 50 / -15 ° C in the conventional brine method. The temperature of the carbon dioxide secondary refrigerant in the ice heat storage system B of the present embodiment is −7 ° C. The temperature of the brine in the conventional brine system is −10 ° C. → −5 ° C. The load is 100 KW in both the present embodiment and the conventional brine system. Under these operating conditions, as shown in FIG. 2, the present embodiment was able to reduce the total power consumption of the compressor and the pump by 23% as compared with the conventional brine system.
[0046]
FIG. 3 is a diagram comparing the total of the piping work cost and the cold insulation work cost of the load side cooling system D according to the present embodiment with the corresponding conventional device (cold water circulation system). The conditions are as shown in FIG. The pipe length (one way) is 50 m in both the present embodiment and the conventional cold water circulation system. The pipe material is a carbon steel pipe for a pressure pipe in the present embodiment, and a stainless steel pipe in a conventional cold water circulation system. The pipe size is 25 A in the present embodiment, and 60 Su in the conventional cold water circulation system. The load is 100 KW in both the present embodiment and the conventional cold water circulation system. The temperature of the fluid is 2 ° C. in the present embodiment, and 3 ° C. in the conventional cold water circulation system. Under these conditions, as shown in FIG. 3, the present embodiment was able to reduce the piping work cost and the cold insulation work cost by 45% as compared with the conventional cold water circulation system.
[0047]
The carbon dioxide secondary refrigerant ice heat storage refrigeration system of the present embodiment configured as described above can greatly reduce the refrigerant charge amount as compared with the conventional direct expansion type ice heat storage device, and has a brine type ice storage system. As shown in FIG. 2, power consumption can be reduced as compared with the heat storage device, so that a refrigeration device with less environmental load can be provided. Further, as shown in FIG. 3, since the piping size of the load side cooling system D can be reduced in diameter, the piping construction cost and the heat insulation construction cost can be reduced as compared with the conventional apparatus.
[0048]
【The invention's effect】
According to the carbon dioxide secondary refrigerant ice heat storage refrigeration apparatus of the present invention, it is possible to suppress the pressure from excessively increasing even when the operation of a part of the apparatus is stopped.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an embodiment of an ice thermal storage refrigeration system for a secondary carbon dioxide gas refrigerant of the present invention.
FIG. 2 is a diagram comparing the power consumption of an embodiment of the carbon dioxide secondary refrigerant ice heat storage refrigeration apparatus of the present invention and the conventional brine type power consumption.
FIG. 3 is a diagram comparing an embodiment of the carbon dioxide gas secondary refrigerant ice heat storage refrigeration apparatus of the present invention with the piping / cooling construction cost of a conventional chilled water circulation system.
[Explanation of symbols]
A Refrigerator system B Ice storage system C Carbon dioxide secondary refrigerant cooling system D Load side cooling system E Load chilled water system F Auxiliary refrigerator system 1 Compressor 2 Condenser 3 Expansion valve 4 Cascade evaporator 5 Heat storage tank 6 Heat for ice making Exchanger 7 Liquid receiver 8 Carbon dioxide gas pump 9 Cold water pump 10 Water cooled condenser 11 Liquid receiver 12 Carbon dioxide gas pump 13 Heat exchanger 14 Cold water pump 15 Load side heat exchangers 16a, 16b Solenoid valve 17 Auxiliary compressor 18 Water cooled condenser 19 pump

Claims

Refrigerator system,
An ice heat storage system in which the secondary refrigerant that has been heat-exchanged in the refrigerator system is introduced into the ice making heat exchanger to perform heat storage,
A carbon dioxide gas secondary refrigerant cooling system that cools the carbon dioxide gas secondary refrigerant with cold water obtained by the ice stored in the ice heat storage system,
A load-side cooling system that cools load-side chilled water with the carbon dioxide gas secondary refrigerant cooled by the chilled water of the carbon dioxide gas secondary refrigerant cooling system;
A second-refrigerant-carbon-carbon-refrigerant ice storage refrigeration system comprising: a first pressure-rise suppressing unit that suppresses the pressure of the load-side cooling system from becoming equal to or higher than a set value.

The carbon dioxide secondary refrigerant ice heat storage refrigeration apparatus according to claim 1,
The secondary heat exchanged in the refrigerator system is a carbon dioxide secondary refrigerant ice heat storage refrigeration apparatus that is a carbon dioxide secondary refrigerant.

The carbon dioxide secondary refrigerant ice heat storage refrigeration apparatus according to claim 2, wherein the load-side cooling system includes a first receiver for storing the carbon dioxide secondary refrigerant cooled and liquefied by the cold water,
The ice heat storage system includes a second liquid receiver that stores the carbon dioxide secondary refrigerant that has been heat-exchanged and liquefied in the refrigerator system,
In the first pressure rise suppression unit, the gas in the first liquid receiver is transferred to the second liquid receiver, so that the pressure of the load-side cooling system is suppressed from being equal to or higher than the set value. Refrigeration system for carbon dioxide secondary refrigerant ice storage.

4. The carbon dioxide secondary refrigerant ice heat storage refrigeration apparatus according to claim 3, wherein the gas in the first liquid receiver transferred to the second liquid receiver is a carbon dioxide gas liquid in the first liquid receiver. 5. An ice heat storage refrigeration system for a secondary carbon dioxide gas that has been evaporated.

Refrigerator system,
An ice heat storage system in which the carbon dioxide secondary refrigerant heat-exchanged in the refrigerator system is introduced into the ice-making heat exchanger to perform heat storage,
A carbon dioxide gas secondary refrigerant cooling system that cools the carbon dioxide gas secondary refrigerant with cold water obtained by the ice stored in the ice heat storage system,
A load-side cooling system that cools load-side chilled water with the carbon dioxide gas secondary refrigerant cooled by the chilled water of the carbon dioxide gas secondary refrigerant cooling system;
A second carbon dioxide refrigerant ice heat storage refrigeration apparatus, comprising: a second pressure rise suppression unit that suppresses the pressure of the ice heat storage system from reaching a predetermined value or higher.

The carbon dioxide secondary refrigerant ice heat storage refrigeration apparatus according to claim 5, wherein the load-side cooling system includes a first receiver for storing the carbon dioxide secondary refrigerant cooled and liquefied by the cold water,
The ice heat storage system includes a second liquid receiver that stores the carbon dioxide secondary refrigerant that has been heat-exchanged and liquefied in the refrigerator system,
The second pressure rise suppression unit includes an auxiliary compressor and a water-cooled condenser,
The auxiliary compressor compresses gas in the second liquid receiver, and the water-cooled condenser condenses the gas compressed by the auxiliary compressor with the cold water, and the condensed carbon dioxide gas liquid. Is an ice thermal storage refrigeration system for a secondary carbon dioxide gas transferred to the first liquid receiver.

Refrigerator system,
An ice heat storage system in which the carbon dioxide secondary refrigerant heat-exchanged in the refrigerator system is introduced into the ice-making heat exchanger to perform heat storage,
A carbon dioxide gas secondary refrigerant cooling system that cools the carbon dioxide gas secondary refrigerant with cold water obtained by the ice stored in the ice heat storage system,
A load-side cooling system that cools load-side chilled water with the carbon dioxide gas secondary refrigerant cooled by the chilled water of the carbon dioxide gas secondary refrigerant cooling system;
A carbon dioxide secondary refrigerant ice storage refrigeration system comprising: a pressure rise suppression unit that suppresses the pressure of the load-side cooling system from becoming equal to or higher than a set value and that prevents the pressure of the ice heat storage system from becoming equal to or higher than a predetermined value. apparatus.

The carbon dioxide secondary refrigerant ice heat storage refrigeration apparatus according to claim 7, wherein the load-side cooling system includes a first receiver for storing the carbon dioxide secondary refrigerant cooled and liquefied by the cold water,
The ice heat storage system includes a second liquid receiver that stores the carbon dioxide secondary refrigerant that has been heat-exchanged and liquefied in the refrigerator system,
The pressure rise suppression unit includes an auxiliary compressor and a water-cooled condenser,
In the pressure rise suppression unit, the gas in the first liquid receiver is transferred to the second liquid receiver, so that the pressure of the load-side cooling system is suppressed from being equal to or higher than the set value,
The auxiliary compressor compresses the gas in the second liquid receiver, and the water-cooled condenser condenses the gas compressed by the auxiliary compressor with the cold water, and the condensed carbon dioxide gas liquid. Is transferred to the first liquid receiver, whereby the pressure of the ice heat storage system is suppressed from becoming equal to or higher than the predetermined value.

The carbon dioxide gas secondary refrigerant ice heat storage refrigeration apparatus according to any one of claims 5, 6, 7, and 8,
An operation of the refrigerator system and the ice storage system is stopped during daytime.

The carbon dioxide gas secondary refrigerant ice storage refrigeration apparatus according to any one of claims 1, 2, 3, 4, 7, and 8,
An operation of the carbon dioxide secondary refrigerant cooling system and the load side cooling system is stopped at night, and the operation of the carbon dioxide secondary refrigerant ice storage refrigeration system is stopped.