JP2004205116A

JP2004205116A - Cold and hot water generator and control method thereof

Info

Publication number: JP2004205116A
Application number: JP2002375208A
Authority: JP
Inventors: Yasuji Ogoshi; 靖二大越; Tomoaki Tanabe; 智明田邉
Original assignee: Toshiba Carrier Corp
Current assignee: Carrier Japan Corp
Priority date: 2002-12-25
Filing date: 2002-12-25
Publication date: 2004-07-22

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high performance cold/hot water generator capable of supplying hot water at a high temperature. <P>SOLUTION: The cold/hot water generator is provided with a refrigerant amount control mechanism provided at the outlet of a water heat exchanger provided in a heat pump refrigerating cycle. The refrigerant amount control mechanism controls the amount of a cooling medium to be circulated in the refrigerating cycle depending on a boiling temperature target value. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明はヒートポンプを用いた冷温水発生装置およびその制御方法に係わり、特に冷媒を制御し高温の出湯温度が得られる冷温水発生装置およびその制御方法に関する。
【０００２】
【従来の技術】
従来、冷温水発生装置は、図９に示すように、圧縮機３３、四方弁３４、水熱交換器３５、絞り装置３７、空気熱交換器３８が順次連結されて冷凍サイクル３２が構成されていた。従来の冷温水発生装置において、温水発生時、圧縮機３３から吐出される冷媒は、四方弁３４を通り水熱交換器３５で凝縮され、絞り装置３７、空気熱交換器３８を介して圧縮機３３に還流するようになっており、水熱交換器３８で熱交換された給水は、温水になり、ポンプ３９で給湯されていた。
【０００３】
しかしながら、従来の冷温水発生装置では、表１および図２に示すように、温水発生運転時、性能が最もよい冷媒量と、最高沸上温度が得られる冷媒量が異なっていたため、いずれか（性能あるいは最高沸上温度）を優先させた冷媒量としていた。例えば、最高沸上温度８０℃が必要な冷温水発生装置の場合は、冷媒量を８００ｇとしていた。そのため、沸上温度６５℃の場合では、循環する冷媒量が少なく、過冷却量が少なくなり性能が悪かった。
【０００４】
また、従来の冷温水発生装置の制御方法においては、絞り装置３７は、目標沸上温度にかかわらず、スーパーヒート量（吸込み温度Ｔｓ−蒸発温度Ｔｅ）（以下、ＳＨという。）が一定となるようコントロールされていた。このため、表２に示すように、吐出温度（以下、Ｔｄという。）＜１０５℃以下という圧縮機の信頼性上の制約から、運転可能Ｈｚが制限され、最高沸上温度をあまり高くできなかった。
【０００５】
なお、特許文献１には、外気温度および／または給水温度に応じて、リキッドタンクの温度調整手段を備え、季節に関係なく、冷凍サイクル内に適量の冷媒を循環させて、長期に連続運転が可能で、安定した出湯運転が可能な冷温水発生装置が記載されているが、特許文献１の冷温水発生装置は、ＣＯＰが最もよい冷媒量と最も高い沸上温度を得られる冷媒量とに容易に変更することができず、高温の出湯温度が可能あるいは性能がよい冷温水発生装置が得られない。
【０００６】
また、特許文献２には、除霜バイパス弁を設け、除霜時、流量制御弁を所定の開度に制御して、スーパーヒート量一定制御を行ない、除霜を短時間で行なう冷温水発生装置が記載されているが、沸上温度目標値に応じて、液冷媒の絞りを変え、スーパーヒート量を制御し、高温の沸上温度が得られるものではない。
【０００７】
【特許文献１】
特開平２００２−１１５９２４号公報（段落番号［００２６］、００２７、００３０、図１）
【０００８】
【特許文献２】
特開平２００２−２４３２７６号公報（段落番号［００７９］、図１）
【０００９】
【発明が解決しようとする課題】
本発明は上述した事情を考慮してなされたもので、高温の沸上温度が得られ、かつ、性能がよい冷温水発生装置およびその制御方法を提供することを目的とする。
【００１０】
【課題を解決するための手段】
上記目的を達成するため、本発明の１つの態様によれば、圧縮機、四方弁、水熱交換器、絞り装置、空気熱交換器が順次連結されて冷凍サイクルが構成され、前記水熱交換器に給水ロおよび出湯口が連結された冷温水発生装置において、前記水熱交換器の出口に冷媒量調整機構を設け、沸上温度目標値に応じて、前記冷媒量調整機構により前記冷凍サイクル内を循環する冷媒量を調整することを特徴とする冷温水発生装置が提供される。これにより、必要に応じて最高沸上温度が得られ、さらに、通常は冷凍サイクルのＣＯＰが最高での運転が実現される。
【００１１】
好適な一例では、前記冷媒量調整機構は、前記水熱交換器出口に、二方弁、リキッドタンクを順次連結するとともに、前記二方弁、リキッドタンクと並列にキャピラリチューブを連結させる。これにより、構造が簡単であり、かつ冷媒を確実に溜めることができ、信頼性が高い。
【００１２】
また、他の好適な一例では、沸上目標温度が高い場合は、前記リキッドタンクに冷媒を溜め、沸上目標温度が低い場合は、前記リキッドタンクに冷媒を溜めないようにする。これにより、最高沸上温度と高ＣＯＰ運転が実現される。
【００１３】
また、他の好適な一例では、前記リキッドタンクは、最高ＣＯＰが得られる冷媒量と、最高沸上温度が得られる冷媒量の差を吸収できる容量である。これにより、ＣＯＰが最もよい冷媒量と最も高い沸上温度を得られる冷媒量との変更が容易に実現される。
【００１４】
また、他の好適な一例では、前記冷凍サイクルに充填される冷媒量は、最高ＣＯＰが得られる量とする。
【００１５】
また、本発明の他の態様によれば、能力可変の圧縮機、四方弁、水熱交換器、絞り装置、空気熱交換器を順次連結することで冷凍サイクルが構成され、水熱交換器には給水口、出湯口が連結された冷温水発生装置の制御方法において、沸上温度目標値に応じた目標スーパーヒート量を設定し、前記絞り装置の絞り量を変え、スーパーヒート量を制御することを特徴とする冷温水発生装置の制御方法が提供される。これにより、沸上温度目標値に応じて、液冷媒の絞りを変え、スーパーヒート量を制御し、従来と比較し高温の沸上温度が実現される。
【００１６】
また、他の好適な一例では、沸上目標温度が低い場合は、目標スーパーヒート量一定制御を行ない、沸上目標温度が高い場合は、吐出温度一定制御を行なう。これにより、効率よくかつ安全に高い沸上温度が実現される。
【００１７】
また、他の好適な一例では、沸上目標温度が高い場合は、目標スーパーヒート量が小さい状態で運転を開始し、吐出温度が一定値以上となった場合、吐出温度一定制御へ切り換える。これにより、圧縮機の周波数をアップでき、吐出温度に制約があっても、高Ｈｚまで運転可能となり、高い沸上温度が実現される。
【００１８】
また、他の好適な一例では、沸上目標温度が高くなるにつれ目標スーパーヒート量を小さくする。冷媒にＲ４１０ＡまたはＲ４０７Ｃを用いることで、ＣＯ_２を用いた場合に比べ圧縮機の吐出圧力がさほど高くなく特別な高耐圧設計を不要としてコストの低減が実現される。
【００１９】
【発明の実施の形態】
以下、本発明に係わる冷温水発生装置の一実施形態について添付図面を参照して説明する。
【００２０】
図３は本発明に係わる一実施形態の冷温水発生装置の概念図を示す。
【００２１】
図３に示すように、本実施形態の冷温水発生装置１は、ヒートポンプ式の冷凍サイクル２を有しており、この冷凍サイクル２は、能力可変の圧縮機３、四方弁４、水熱交換器５が順次連結され、さらに、二方弁６ａ、リキッドタンク６ｂが順次連結されるとともに、二方弁６ａ、リキッドタンク６ｂと並列にキャピラリチューブ６ｃが連結されてなる冷媒量調整機構６が連結され、それぞれの回路は合流後、絞り装置７、空気熱交換器８、四方弁４を介して圧縮機３に連結されることで形成されている。冷媒量調整機構６は、上記構造を有するので、構造が簡単であり、かつ冷媒を確実に溜めることができ、信頼性が高い。
【００２２】
また、冷温水発生装置１には、水系統１１が設けられており、この水系統１１には、上記水熱交換器５と、貯水タンク１２の頂部側に設けられた給湯口１３と、貯水タンク１２と、貯水タンク１２の底部に設けられた取水口１４と、給水側パイプ１６ｂに設けられたポンプ１５が順次連通されてなる循環路１６が形成され、また、給湯口１３には、台所等の蛇口（図示せず）等に接続される配管１７が接続され、さらに、貯湯タンク１２の底部側には、給水圧を加えながら貯湯タンク１２に市水を供給するための給水配管１８が接続されている。
【００２３】
また、出湯側パイプ１６ａには、温度センサ１９が取付けられており、温水の沸上温度（Ｔｗ）は、温度センサ１９の温度が一定となるように、装置全体を制御しインバータ回路（図示せず）を含む制御装置２０を介して、圧縮機３の運転周波数を可変させることで制御されるようになっている。冷凍サイクル２に充填される冷媒は、例えばＲ４１０Ａであり、その量は、定格運転時（例えば、沸上温度６５℃時）にＣＯＰが最もよい冷媒量（例えば、１０００ｇ）であり、リキッドタンク８の容量は、最も高い沸上温度を得られる冷媒量（８００ｇ）との差を吸収できる容量（例えば、２００ｃｃ）であるのが好ましい。これにより、ＣＯＰが最もよい冷媒量と最も高い沸上温度を得られる冷媒量との変更が容易にできる。また、冷媒にＲ４１０Ａを用いることにより、ＣＯ_２を用いた場合に比べて圧縮機の吐出圧力がさほど高くなく冷凍サイクルの構成部品に特別な高耐圧設計をする必要がないので、信頼性が高い上に、コストの低減ができる。更には、冷凍サイクルに既存の空調機の室外ユニットを流用できる。
【００２４】
上記冷凍サイクル２は、予め行われた試験により、表１に示すような特性を有するように設定されている。
【００２５】
【表１】

【００２６】
なお、図１中、符号２１は吐出温度センサ、２２は吸込み温度センサ、２３は蒸発温度センサ、２４は温度センサであり、各々取付け部の温度を検出して、制御装置２０に温度信号を送るようになっている。
【００２７】
次に、本実施形態の冷温水発生装置を用いた給湯方法について説明する。
【００２８】
「最高（８０℃）沸上時」
図1に示すように、最高（８０℃）沸上を希望する使用者により、リモート操作により、制御装置２０に入力され、この制御装置２０を介して予め二方弁６ａは開放される。二方弁６ａが開放された状態で、冷凍サイクル２は運転され、安定状態になると図２に示すモリエル線図のような状態になる。このような状態において、圧縮機３から吐出された冷媒は、四方弁４を通り、水熱交換器５に接続された給水側パイプ１６ｂを流れる給水と熱交換し、冷却されて凝縮され、給水は加熱される。凝縮された冷媒は、二方弁６ａ、リキッドタンク６ｂ、絞り装置７を流れ、空気熱交換器８で蒸発し、四方弁４を介して圧縮機１に吸入されて還流される。このような冷媒の循環過程において、水熱交換器５で凝縮液化された冷媒は、リキッドタンク６ｂに溜められる。リキッドタンク６ｂは、当初に冷凍サイクル２に充填した冷媒量（１０００ｇ）のうち、最高沸上温度が得られる冷媒量との余剰分（２００ｃｃ）を吸収できる容量となっているため、冷凍サイクル２を流れる冷媒量は８００ｇとなり、圧縮機１の最高運転可能周波数は８０Ｈｚとなり、最高沸上温度８０℃が得られる。図２からもわかるように、この時のＣＯＰ（成績係数）＝Ｑ_８００／ｑであるＣＯＰは表１に示すように３．６となる。
【００２９】
「６５℃沸上時」
図３に示すように、６５℃沸上を希望する使用者によりリモート操作により、予め二方弁６ａは閉止される。二方弁６ａが閉止された状態で、冷凍サイクル２は運転され、圧縮機３から吐出された冷媒は、四方弁４を通り、水熱交換器５に設けられた給水側パイプ１６ｂを流れる給水と熱交換し、冷却されて凝縮され、給水は加熱される。凝縮された冷媒は、二方弁６ａが閉止状態にあるためキャピラリチューブ６ｃへ流れ、空気熱交換器８で蒸発した後、四方弁４を介して圧縮機３に吸入されて環流される。このような冷媒の循環過程において、水熱交換器５で凝縮液化された冷媒は、キャピラリチューブを通って流れるため、リキッドタンク８に液冷媒が溜められることはない。従って、冷凍サイクル２を流れる冷媒量は、当初に冷凍サイクル２に充填した冷媒量、すなわち１０００ｇが常時冷凍サイクル内を循環することになり、定常運転時の沸上温度６５℃が得られる。図２からもわかるように、この時のＣＯＰ（成績係数）＝Ｑ_１０００／ｑであるＣＯＰは表１に示すように最高の４．０となる。
【００３０】
上記のように本実施形態の冷温水発生装置によれば、水熱交換器５の出口に冷媒量調整機構６が設けられ、沸上目標温度に応じて循環冷媒量を調整することで、必要に応じて最高沸上温度が得られ、さらに、通常は冷凍サイクル２のＣＯＰが最高での運転が可能になる。
【００３１】
次に本発明に係わる冷温水発生装置の制御方法について説明する。
【００３２】
上記一実施形態が冷媒量調整機構により冷凍サイクル内を循環する冷媒量を調整して沸上温度を制御するのに対して、本発明に係わる冷温水発生装置の制御方法は、冷媒の絞り制御してスーパーヒート量を制御し、さらに、圧縮機の回転数も制御するものである。
【００３３】
例えば、図４に示すように、本発明に係わる冷温水発生装置の制御方法に用いられる冷温水発生装置１Ａは、ヒートポンプ式の冷凍サイクル２Ａを有しており、この冷凍サイクル２Ａは、能力可変の圧縮機３Ａ、四方弁４Ａ、水熱交換器５Ａ、絞り装置７Ａ、空気熱交換器８Ａ、四方弁４Ａを介して圧縮機３Ａに連結されることで形成されている。また、出湯側パイプ１６Ａａには、温度センサ１９Ａが取付けられており、温水の沸上温度（Ｔｗ）は、温度センサ１９Ａの温度が一定となるように、制御装置２０Ａを介して、圧縮機３Ａの運転周波数を可変させることで制御されるようになっている。
【００３４】
上記絞り装置７Ａは、流量調整自在な電動膨張弁により構成されており、制御装置２０Ａからの入力により、そこを流れる冷媒流量を制御できるようになっている。また、圧縮機３Ａの吸込み側連通管２Ａａには吸込み温度センサ２２Ａが設けられて、さらに、空気熱交換器８Ａには蒸発温度を検知する蒸発温度センサ２３Ａが設けられており、吸込み温度Ｔｓ−蒸発温度Ｔｅから冷媒の空気熱交換器８ＡにおけるＳＨが演算できるようになっており、また、圧縮機３Ａから吐出される冷媒のＴｄは、吐出側連通管２Ａｂに取付けられた吐出温度センサ２１Ａによって検知されるようになっている。
【００３５】
従って、絞り装置７Ａにより空気熱交換器８Ａに流入される冷媒量を制御して、冷媒の空気熱交換器８Ａの出口におけるＳＨを制御でき、圧縮機３Ａから吐出される冷媒の温度を制御できるようになっている。ここで、ＳＨは、目標沸上温度な応じて目標値が設定され、絞り装置７Ａにより制御される。
【００３６】
上記冷凍サイクル２Ａは、予め行われた試験によれば、表２に示すような特性を有するように設定されている。他の構成は図１に示す冷温水発生装置と異ならないので、同一符号を付して説明は省略する。
【００３７】
また、本発明に係わる冷温水発生装置の制御方法について説明する。
【００３８】
【表２】

【００３９】
「６５℃沸上時」
図４に示すような冷凍サイクル２Ａが定常運転になった状態で、６５℃沸上を希望する使用者により、制御装置２０Ａを介して、絞り装置７Ａは、表２に示すように、目的ＳＨが５ｄｅｇになるように開度が制御され、図５に示すように、空気熱交換器８Ａのガス冷媒量が多くなり、ＳＨ＝５ｄｅｇで制御される。このようにＳＨが制御された状態で、冷凍サイクル２Ａは運転され、安定状態になると図２に示すモリエル線図のような状態になる。このような状態において、圧縮機３Ａから吐出された冷媒は、四方弁４Ａを通り、水熱交換器５Ａに接続された給水側パイプ１６Ａｂを流れる給水と熱交換し、冷却されて凝縮され、給水は６５℃に加熱される。凝縮された冷媒は、絞り装置７Ａを流れ、空気熱交換器８Ａで蒸発し、四方弁４Ａを介して圧縮機１Ａに吸入されて環流される。
【００４０】
このような冷媒の循環過程において、空気熱交換器８Ａの出口側に取付けられた吸込み温度センサ２２Ａにより、検知された空気熱交換器８Ａの出口の冷媒温度と、温度センサ２４Ａで検出される蒸発温度との差、すなわちＳＨが演算され、目標ＳＨ量が一定、５ｄｅｇになるように圧縮機３Ａの運転周波数が制御され、保持される。
【００４１】
この時、沸上目標温度は６５℃と低いため吐出温度が低くてもよく、適度のスーパーヒート量が取れた効率的な運転が可能となる。
【００４２】
「７０℃沸上時」
制御装置２０Ａを介して、絞り装置７Ａは、表２に示すように目的ＳＨが３ｄｅｇになるように開度が制御され、ＳＨ＝３ｄｅｇで制御される。このＳＨが制御された状態で、冷凍サイクル２Ａは運転される。水熱交換器５Ａに接続された給水側パイプ１６Ａｂを流れる給水と熱交換し、冷却されて凝縮され、給水は７０℃に加熱される。６５℃沸上時に比べＴｄ温度は上がる傾向であるが、ＳＨが３ｄｅｇで制御されているためＴｄが１００℃を超えることはなく、７０℃沸上げが可能となる。
【００４３】
「７５℃沸上時」
制御装置２０Ａを介して、絞り装置７Ａは、表２に示すように目的ＳＨが２ｄｅｇになるように開度が制御され、ＳＨ＝２ｄｅｇで制御される。このＳＨが制御された状態で、冷凍サイクル２Ａは運転される。水熱交換器５Ａに接続された給水側パイプ１６Ａｂを流れる給水と熱交換し、冷却されて凝縮され、給水は７５℃に加熱される。７０℃沸上時と同様、ＳＨが２ｄｅｇで制御されているためＴｄが１００℃を超えることはなく、７５℃沸上げが可能となる。
【００４４】
「８０℃沸上時」
制御装置２０Ａを介して、絞り装置７Ａは、表２に示すように目的ＳＨが１ｄｅｇになるように開度が制御され、ＳＨ＝１ｄｅｇに制御される。
【００４５】
このＳＨが制御された状態で、冷凍サイクル２Ａは運転される。水熱交換器５Ａに接続された給水側パイプ１６Ａｂを流れる給水と熱交換し、冷却されて凝縮され、給水は８０℃に加熱される。
【００４６】
このような８０℃沸上時、圧縮機３ＡのＴｄが上昇し、１０４℃を超えると、絞り装置７Ａは、Ｔｄセンサの値が１０３℃になるように制御される。これにより、圧縮機３Ａの周波数をアップでき、Ｔｄ＜１０５℃という制約条件下でも、最高Ｈｚ９０まで運転可能となり、８０℃の沸上温度が得られる。
【００４７】
上記のように本発明に係わる冷温水発生装置の制御方法によれば、沸上温度目標値に応じて、液冷媒の絞りを変え、スーパーヒート量を制御し、従来と比較し高温の沸上温度が得られる。
【００４８】
また、上記一実施形態に用いられる冷媒量調整機構の第１変形例について説明する。
【００４９】
本第１変形例は、図１に示す一実施形態に用いられる冷媒量調整機構のキャピラリチューブと直列に第２の二方弁が付加されたものである。
【００５０】
例えば、図７に示すように、冷媒量調整機構６Ｂのキャピラリチューブ６Ｂｃに直列に第２の二方弁６Ｂｄが設けられている。これにより、第１実施形態と同様の効果が得られるほか、キャピラリチューブ６Ｂｃを介して流れる冷媒を完全に止めることができる。
【００５１】
さらに、一実施形態に用いられる冷媒量調整機構の第２変形例について説明する。
【００５２】
本第２変形例は、図１に示す第１実施形態に用いられる冷媒量調整機構のリキッドタンクと直列に第２のキャピラリチューブが付加されたものである。
【００５３】
例えば、図８に示すように、冷媒量調整機構６Ｃのリキッドタンク６Ｂｂに直列に第２のキャピラリチューブ６Ｂｅが設けられている。これにより、第１実施形態と同様の効果が得られるほか、冷媒の逆流が防止される。
【００５４】
また、上記第１変形例と上記第２変形例を組合せた構造、すなわち、図７に示すリキッドタンク６ｂと直列に、図８に示すように第２のキャピラリチューブ６Ｂｅを設けるようにしてもよい。
【００５５】
【発明の効果】
本発明に係わる冷温水発生装置によれば、高温の沸上温度が得られ、かつ、性能がよい冷温水発生装置を提供することができる。
【図面の簡単な説明】
【図１】本発明に係わる冷温水発生装置の一実施形態の概念図。
【図２】本発明に係わる冷温水発生装置に用いられる冷凍サイクルのモリエル線図。
【図３】本発明に係わる冷温水発生装置の一実施形態の動作状態を示す概念図。
【図４】本発明に係わる冷温水発生装置の制御方法に用いられる冷温水発生装置の概念図。
【図５】本発明に係わる冷温水発生装置の制御方法に用いられる冷温水発生装置の空気熱交換器の状態を示す概念図。
【図６】本発明に係わる冷温水発生装置の制御方法に用いられる冷温水発生装置の絞り装置の制御図。
【図７】本発明に係わる冷温水発生装置の第１実施形態に用いられる冷媒量調整機構の第１変形例の概念図。
【図８】本発明に係わる冷温水発生装置の第１実施形態に用いられる冷媒量調整機構の第２変形例の概念図。
【図９】従来の冷温水発生装置の概念図。
【符号の説明】
１冷温水発生装置
２冷凍サイクル
３圧縮機
４四方弁
５水熱交換器
６冷媒量調整機構
６ａ二方弁
６ｂリキッドタンク
６ｃキャピラリチューブ
７絞り装置
８空気熱交換器
１１水系統
１２貯水タンク
１３給湯口
１４取水口
１５ポンプ
１６循環路
１６ａ出湯側パイプ
１６ｂ給水側パイプ
１７配管
１８給水配管
１９温度センサ
２０制御装置
２１〜２４温度センサ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hot / cold water generator using a heat pump and a control method thereof, and more particularly to a cold / hot water generator capable of controlling a refrigerant to obtain a high tap water temperature and a control method thereof.
[0002]
[Prior art]
Conventionally, as shown in FIG. 9, in a cold / hot water generator, a refrigeration cycle 32 is configured by sequentially connecting a compressor 33, a four-way valve 34, a water heat exchanger 35, a throttle device 37, and an air heat exchanger 38. Was. In the conventional cold / hot water generator, when hot water is generated, the refrigerant discharged from the compressor 33 passes through the four-way valve 34, is condensed in the water heat exchanger 35, and is condensed through the expansion device 37 and the air heat exchanger 38. The feed water is returned to the feed water 33, and the feed water that has been heat-exchanged by the water heat exchanger 38 has become hot water and has been fed by the pump 39.
[0003]
However, in the conventional cold / hot water generator, as shown in Table 1 and FIG. 2, during the hot water generation operation, the amount of refrigerant having the best performance and the amount of refrigerant at which the highest boiling temperature is obtained are different. Performance or maximum boiling temperature). For example, in the case of a cold / hot water generator requiring a maximum boiling temperature of 80 ° C., the amount of the refrigerant is set to 800 g. Therefore, when the boiling temperature was 65 ° C., the amount of circulating refrigerant was small, the amount of supercooling was small, and the performance was poor.
[0004]
Further, in the conventional control method of the cold / hot water generator, the expansion device 37 has a constant superheat amount (suction temperature Ts-evaporation temperature Te) (hereinafter referred to as SH) regardless of the target boiling temperature. Was controlled as follows. Therefore, as shown in Table 2, the operable Hz is limited due to the restriction on the reliability of the compressor that the discharge temperature (hereinafter, referred to as Td) <105 ° C. or less, and the maximum boiling temperature cannot be too high. Was.
[0005]
In addition, Patent Document 1 includes a liquid tank temperature adjusting means in accordance with the outside air temperature and / or the supply water temperature, irrespective of the season, circulates an appropriate amount of refrigerant in the refrigeration cycle, and continuously operates for a long time. Although a cold and hot water generator capable of performing a stable tapping operation is described, the cold and hot water generator of Patent Document 1 has a COP having the best refrigerant amount and a refrigerant amount capable of obtaining the highest boiling temperature. Since it cannot be easily changed, a hot and cold water generating device capable of a high tap water temperature or having good performance cannot be obtained.
[0006]
Further, in Patent Document 2, a defrost bypass valve is provided, and at the time of defrost, the flow rate control valve is controlled to a predetermined opening to perform constant control of the superheat amount to generate defrost in a short time. Although an apparatus is described, it is not possible to obtain a high boiling temperature by controlling the amount of superheat by changing the throttle of the liquid refrigerant according to the boiling temperature target value.
[0007]
[Patent Document 1]
JP-A-2002-115924 (paragraph numbers [0026], 0027, 0030, FIG. 1)
[0008]
[Patent Document 2]
JP-A-2002-243276 (paragraph number [0079], FIG. 1)
[0009]
[Problems to be solved by the invention]
The present invention has been made in consideration of the above-described circumstances, and has as its object to provide a cold and hot water generating apparatus capable of obtaining a high boiling temperature and having good performance, and a control method thereof.
[0010]
[Means for Solving the Problems]
According to one embodiment of the present invention, a compressor, a four-way valve, a water heat exchanger, a throttle device, and an air heat exchanger are sequentially connected to form a refrigeration cycle. In a cold / hot water generator in which a water supply unit and a hot water outlet are connected to a heat exchanger, a refrigerant amount adjusting mechanism is provided at an outlet of the water heat exchanger, and the refrigeration cycle is controlled by the refrigerant amount adjusting mechanism in accordance with a boiling temperature target value. There is provided a cold and hot water generator characterized by adjusting the amount of refrigerant circulating in the inside. As a result, a maximum boiling temperature can be obtained if necessary, and furthermore, the operation of the refrigeration cycle with the highest COP is usually realized.
[0011]
In a preferred example, the refrigerant amount adjusting mechanism sequentially connects a two-way valve and a liquid tank to the water heat exchanger outlet, and connects a capillary tube in parallel with the two-way valve and the liquid tank. Thus, the structure is simple, the refrigerant can be reliably stored, and the reliability is high.
[0012]
In another preferred example, when the boiling target temperature is high, the refrigerant is stored in the liquid tank, and when the boiling target temperature is low, the refrigerant is not stored in the liquid tank. Thereby, the maximum boiling temperature and the high COP operation are realized.
[0013]
In another preferred example, the liquid tank has a capacity capable of absorbing a difference between a refrigerant amount at which a maximum COP is obtained and a refrigerant amount at which a maximum boiling temperature is obtained. This makes it easy to change between the amount of refrigerant having the best COP and the amount of refrigerant capable of obtaining the highest boiling temperature.
[0014]
Further, in another preferred example, the amount of the refrigerant charged into the refrigeration cycle is an amount that allows the highest COP to be obtained.
[0015]
According to another aspect of the present invention, a refrigeration cycle is configured by sequentially connecting a variable capacity compressor, a four-way valve, a water heat exchanger, a throttle device, and an air heat exchanger. Is a method for controlling a hot / cold water generator in which a water inlet and a tap is connected, wherein a target superheat amount is set according to a boiling temperature target value, a throttle amount of the throttle device is changed, and a superheat amount is controlled. A method for controlling a cold / hot water generator is provided. Thereby, the throttle of the liquid refrigerant is changed in accordance with the boiling temperature target value, the amount of superheat is controlled, and a higher boiling temperature than that of the related art is realized.
[0016]
In another preferred example, when the boiling target temperature is low, the target superheat amount constant control is performed, and when the boiling target temperature is high, the discharge temperature constant control is performed. Thereby, a high boiling temperature is realized efficiently and safely.
[0017]
In another preferred example, when the boiling target temperature is high, the operation is started in a state where the target superheat amount is small, and when the discharge temperature becomes equal to or higher than a predetermined value, the control is switched to the discharge temperature constant control. As a result, the frequency of the compressor can be increased, and even if the discharge temperature is restricted, the compressor can be operated up to a high Hz, and a high boiling temperature can be realized.
[0018]
In another preferred example, the target superheat amount is reduced as the boiling target temperature increases. By using R410A or R407C the refrigerant, the discharge pressure of the compressor compared with the case of using CO ₂ to reduce the cost of is achieved a special high-voltage design as required not so high.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a cold and hot water generator according to the present invention will be described with reference to the accompanying drawings.
[0020]
FIG. 3 shows a conceptual diagram of the cold / hot water generator of one embodiment according to the present invention.
[0021]
As shown in FIG. 3, the cold / hot water generator 1 of the present embodiment has a heat pump type refrigeration cycle 2, and this refrigeration cycle 2 has a variable capacity compressor 3, a four-way valve 4, a water heat exchange The vessel 5 is sequentially connected, and further, the two-way valve 6a and the liquid tank 6b are sequentially connected, and the refrigerant amount adjusting mechanism 6, which is connected to the capillary tube 6c in parallel with the two-way valve 6a and the liquid tank 6b, is connected. The respective circuits are formed by being connected to the compressor 3 via the expansion device 7, the air heat exchanger 8, and the four-way valve 4 after the merging. Since the refrigerant amount adjusting mechanism 6 has the above structure, the structure is simple, the refrigerant can be reliably stored, and the reliability is high.
[0022]
Further, the cold / hot water generator 1 is provided with a water system 11. The water system 11 includes the water heat exchanger 5, a hot water supply port 13 provided on the top side of the water storage tank 12, and a water storage system. A circulation path 16 is formed in which a tank 12, a water intake port 14 provided at the bottom of the water storage tank 12, and a pump 15 provided on a water supply side pipe 16 b are sequentially communicated. A pipe 17 connected to a faucet (not shown) or the like is connected to the bottom of the hot water storage tank 12, and a water supply pipe 18 for supplying city water to the hot water storage tank 12 while applying water supply pressure. It is connected.
[0023]
A temperature sensor 19 is attached to the tapping-side pipe 16a. The temperature of the boiling water (Tw) of the hot water is controlled by controlling the entire apparatus so that the temperature of the temperature sensor 19 becomes constant. ) Is controlled by varying the operating frequency of the compressor 3 via the control device 20 including The refrigerant to be charged into the refrigeration cycle 2 is, for example, R410A, the amount of which is the refrigerant amount (for example, 1000 g) having the best COP at the time of rated operation (for example, at a boiling temperature of 65 ° C.). Is preferably a capacity (for example, 200 cc) capable of absorbing a difference from a refrigerant amount (800 g) at which the highest boiling temperature can be obtained. Thereby, it is possible to easily change the amount of refrigerant having the best COP and the amount of refrigerant capable of obtaining the highest boiling temperature. Also, by using R410A for the refrigerant, the discharge pressure of the compressor is not so high as compared with the case of using CO _2, and there is no need to design special high pressure resistance for the components of the refrigeration cycle. In addition, costs can be reduced. Furthermore, the outdoor unit of the existing air conditioner can be used for the refrigeration cycle.
[0024]
The refrigeration cycle 2 is set so as to have characteristics as shown in Table 1 by a test performed in advance.
[0025]
[Table 1]

[0026]
In FIG. 1, reference numeral 21 denotes a discharge temperature sensor, 22 denotes a suction temperature sensor, 23 denotes an evaporation temperature sensor, and 24 denotes a temperature sensor, each of which detects the temperature of the mounting portion and sends a temperature signal to the control device 20. It has become.
[0027]
Next, a hot water supply method using the cold / hot water generator of the present embodiment will be described.
[0028]
"At maximum (80 ° C) boiling"
As shown in FIG. 1, a user who desires the maximum (80 ° C.) boiling is input to the control device 20 by remote operation, and the two-way valve 6a is opened in advance via the control device 20. The refrigeration cycle 2 is operated in a state where the two-way valve 6a is opened, and when the refrigeration cycle 2 is in a stable state, the state is as shown in a Mollier diagram shown in FIG. In such a state, the refrigerant discharged from the compressor 3 passes through the four-way valve 4 and exchanges heat with the feedwater flowing through the feedwater pipe 16b connected to the water heat exchanger 5, and is cooled and condensed to supply water. Is heated. The condensed refrigerant flows through the two-way valve 6a, the liquid tank 6b, and the expansion device 7, evaporates in the air heat exchanger 8, is drawn into the compressor 1 via the four-way valve 4, and is returned. In such a refrigerant circulation process, the refrigerant condensed and liquefied in the water heat exchanger 5 is stored in the liquid tank 6b. The liquid tank 6b has a capacity capable of absorbing a surplus (200 cc) of the refrigerant amount (1000 g) initially charged into the refrigeration cycle 2 with the refrigerant amount at which the maximum boiling temperature is obtained. Is 800 g, the maximum operable frequency of the compressor 1 is 80 Hz, and a maximum boiling temperature of 80 ° C. is obtained. As can be seen from FIG. 2, the COP (coefficient of performance) = Q ₈₀₀ / q at this time is 3.6 as shown in Table 1.
[0029]
"When boiling at 65 ° C"
As shown in FIG. 3, the two-way valve 6a is previously closed by a remote operation by a user who wants to heat up to 65 ° C. With the two-way valve 6a closed, the refrigeration cycle 2 is operated, and the refrigerant discharged from the compressor 3 passes through the four-way valve 4 and flows through the water supply pipe 16b provided in the water heat exchanger 5 to supply water. Heat exchange with the water, cooled and condensed, and the feed water is heated. The condensed refrigerant flows to the capillary tube 6c because the two-way valve 6a is in the closed state, evaporates in the air heat exchanger 8, is drawn into the compressor 3 via the four-way valve 4, and is recirculated. In such a refrigerant circulation process, the refrigerant condensed and liquefied in the water heat exchanger 5 flows through the capillary tube, so that the liquid refrigerant is not stored in the liquid tank 8. Therefore, the amount of the refrigerant flowing through the refrigeration cycle 2 is the amount of the refrigerant initially charged in the refrigeration cycle 2, that is, 1000 g constantly circulates in the refrigeration cycle, and a boiling temperature of 65 ° C. at the time of steady operation is obtained. As can be seen from FIG. 2, the COP (coefficient of performance) = Q ₁₀₀₀ / q at this time is the highest 4.0 as shown in Table 1.
[0030]
As described above, according to the cold / hot water generator of the present embodiment, the refrigerant amount adjusting mechanism 6 is provided at the outlet of the water heat exchanger 5, and the required amount of circulating refrigerant is adjusted according to the target boiling temperature. , The maximum boiling temperature is obtained, and the operation of the refrigeration cycle 2 with the highest COP is generally possible.
[0031]
Next, a control method of the cold / hot water generator according to the present invention will be described.
[0032]
While the above embodiment controls the boiling temperature by adjusting the amount of refrigerant circulating in the refrigeration cycle by the refrigerant amount adjustment mechanism, the control method of the chilled / hot water generator according to the present invention employs the throttle control of the refrigerant. In this way, the amount of superheat is controlled, and the number of revolutions of the compressor is also controlled.
[0033]
For example, as shown in FIG. 4, the cold / hot water generator 1A used in the control method of the cold / hot water generator according to the present invention has a heat pump type refrigeration cycle 2A. 3A, a four-way valve 4A, a water heat exchanger 5A, a throttle device 7A, an air heat exchanger 8A, and a compressor 3A via a four-way valve 4A. A temperature sensor 19A is attached to the tapping-side pipe 16Aa, and the boiling temperature (Tw) of the hot water is controlled by the compressor 3A via the control device 20A so that the temperature of the temperature sensor 19A becomes constant. Is controlled by varying the operating frequency of the motor.
[0034]
The expansion device 7A is configured by an electric expansion valve whose flow rate can be adjusted, and the flow rate of the refrigerant flowing therethrough can be controlled by an input from the control device 20A. The suction side communication pipe 2Aa of the compressor 3A is provided with a suction temperature sensor 22A, and the air heat exchanger 8A is further provided with an evaporation temperature sensor 23A for detecting an evaporation temperature. The SH of the refrigerant in the air heat exchanger 8A can be calculated from the evaporation temperature Te, and the Td of the refrigerant discharged from the compressor 3A is calculated by a discharge temperature sensor 21A attached to the discharge communication pipe 2Ab. It is to be detected.
[0035]
Therefore, by controlling the amount of refrigerant flowing into the air heat exchanger 8A by the expansion device 7A, SH at the outlet of the air heat exchanger 8A of the refrigerant can be controlled, and the temperature of the refrigerant discharged from the compressor 3A can be controlled. It has become. Here, a target value of SH is set according to the target boiling temperature, and is controlled by the expansion device 7A.
[0036]
The refrigeration cycle 2A is set to have characteristics as shown in Table 2 according to a test performed in advance. The other configuration is the same as that of the cold / hot water generator shown in FIG.
[0037]
Further, a control method of the cold / hot water generator according to the present invention will be described.
[0038]
[Table 2]

[0039]
"When boiling at 65 ° C"
In a state where the refrigeration cycle 2A shown in FIG. 4 is in a steady operation, the user who desires to raise the temperature to 65 ° C. through the control device 20A causes the expansion device 7A to perform the target SH as shown in Table 2. Is set to 5 deg, and as shown in FIG. 5, the gas refrigerant amount of the air heat exchanger 8A increases, and control is performed at SH = 5 deg. The refrigeration cycle 2A is operated in a state where the SH is controlled as described above. When the refrigeration cycle 2A becomes stable, a state as shown in a Mollier diagram shown in FIG. 2 is obtained. In such a state, the refrigerant discharged from the compressor 3A passes through the four-way valve 4A, exchanges heat with the feedwater flowing through the feedwater pipe 16Ab connected to the water heat exchanger 5A, is cooled, condensed, and supplied with water. Is heated to 65 ° C. The condensed refrigerant flows through the expansion device 7A, evaporates in the air heat exchanger 8A, is sucked into the compressor 1A via the four-way valve 4A, and is recirculated.
[0040]
In such a refrigerant circulation process, the refrigerant temperature at the outlet of the air heat exchanger 8A detected by the suction temperature sensor 22A attached to the outlet side of the air heat exchanger 8A and the evaporation temperature detected by the temperature sensor 24A. The difference from the temperature, that is, SH is calculated, and the operating frequency of the compressor 3A is controlled and maintained so that the target SH amount is constant at 5 deg.
[0041]
At this time, since the boiling target temperature is as low as 65 ° C., the discharge temperature may be low, and efficient operation with an appropriate amount of superheat can be performed.
[0042]
"When boiling at 70 ° C"
The opening degree of the expansion device 7A is controlled via the control device 20A so that the target SH becomes 3 deg as shown in Table 2, and is controlled at SH = 3 deg. With this SH controlled, the refrigeration cycle 2A is operated. It exchanges heat with the feedwater flowing through the feedwater pipe 16Ab connected to the water heat exchanger 5A, is cooled and condensed, and the feedwater is heated to 70 ° C. Although the Td temperature tends to rise as compared with the case of boiling at 65 ° C., since SH is controlled at 3 deg, Td does not exceed 100 ° C., and boiling at 70 ° C. becomes possible.
[0043]
"When boiling at 75 ° C"
The opening degree of the expansion device 7A is controlled via the control device 20A so that the target SH becomes 2 deg as shown in Table 2, and is controlled at SH = 2 deg. With this SH controlled, the refrigeration cycle 2A is operated. It exchanges heat with the feedwater flowing through the feedwater pipe 16Ab connected to the water heat exchanger 5A, is cooled and condensed, and the feedwater is heated to 75 ° C. As in the case of boiling at 70 ° C., since SH is controlled at 2 deg, Td does not exceed 100 ° C., and boiling at 75 ° C. becomes possible.
[0044]
"When boiling at 80 ° C"
The opening degree of the expansion device 7A is controlled via the control device 20A so that the target SH becomes 1 deg as shown in Table 2, and is controlled to SH = 1 deg.
[0045]
With this SH controlled, the refrigeration cycle 2A is operated. It exchanges heat with the feedwater flowing through the feedwater pipe 16Ab connected to the water heat exchanger 5A, is cooled and condensed, and the feedwater is heated to 80 ° C.
[0046]
At the time of such 80 ° C. boiling, the Td of the compressor 3A rises, and when it exceeds 104 ° C., the expansion device 7A is controlled such that the value of the Td sensor becomes 103 ° C. As a result, the frequency of the compressor 3A can be increased, and the compressor 3A can be operated up to a maximum of 90 even under the constraint condition of Td <105 ° C., and a boiling temperature of 80 ° C. can be obtained.
[0047]
As described above, according to the method for controlling the cold / hot water generator according to the present invention, the throttle of the liquid refrigerant is changed according to the boiling temperature target value, and the superheat amount is controlled. The temperature is obtained.
[0048]
Further, a first modification of the refrigerant amount adjusting mechanism used in the embodiment will be described.
[0049]
In the first modification, a second two-way valve is added in series with the capillary tube of the refrigerant amount adjusting mechanism used in the embodiment shown in FIG.
[0050]
For example, as shown in FIG. 7, a second two-way valve 6Bd is provided in series with the capillary tube 6Bc of the refrigerant amount adjusting mechanism 6B. Accordingly, the same effect as that of the first embodiment can be obtained, and the refrigerant flowing through the capillary tube 6Bc can be completely stopped.
[0051]
Further, a second modified example of the refrigerant amount adjusting mechanism used in the embodiment will be described.
[0052]
In the second modified example, a second capillary tube is added in series with the liquid tank of the refrigerant amount adjusting mechanism used in the first embodiment shown in FIG.
[0053]
For example, as shown in FIG. 8, a second capillary tube 6Be is provided in series with the liquid tank 6Bb of the refrigerant amount adjusting mechanism 6C. Thereby, the same effect as that of the first embodiment is obtained, and the backflow of the refrigerant is prevented.
[0054]
In addition, a structure combining the first modification and the second modification, that is, a second capillary tube 6Be may be provided in series with the liquid tank 6b shown in FIG. 7 as shown in FIG. .
[0055]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the cold / hot water generator according to the present invention, a high boiling temperature can be obtained, and a cold / hot water generator with good performance can be provided.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of one embodiment of a cold / hot water generator according to the present invention.
FIG. 2 is a Mollier diagram of a refrigeration cycle used in the cold / hot water generator according to the present invention.
FIG. 3 is a conceptual diagram showing an operation state of an embodiment of the cold and hot water generation device according to the present invention.
FIG. 4 is a conceptual diagram of a cold / hot water generator used in the method for controlling a cold / hot water generator according to the present invention.
FIG. 5 is a conceptual diagram showing a state of an air heat exchanger of the cold / hot water generator used in the method for controlling the cold / hot water generator according to the present invention.
FIG. 6 is a control diagram of a throttle device of the cold / hot water generator used in the method of controlling the cold / hot water generator according to the present invention.
FIG. 7 is a conceptual diagram of a first modified example of the refrigerant amount adjusting mechanism used in the first embodiment of the cold and hot water generation device according to the present invention.
FIG. 8 is a conceptual diagram of a second modification of the refrigerant amount adjusting mechanism used in the first embodiment of the cold / hot water generator according to the present invention.
FIG. 9 is a conceptual diagram of a conventional cold / hot water generator.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cold and hot water generator 2 Refrigeration cycle 3 Compressor 4 Four-way valve 5 Water heat exchanger 6 Refrigerant amount adjustment mechanism 6a Two-way valve

6b Liquid tank

6c Capillary tube 7 Throttling device 8 Air heat exchanger 11 Water system 12 Water tank 13 Hot water supply Mouth 14 Intake 15 Pump 16 Circulation path 16a Hot-water supply pipe 16b Water supply pipe 17 Pipe 18 Water supply pipe 19 Temperature sensor 20 Control devices 21 to 24 Temperature sensor

Claims

A compressor, a four-way valve, a water heat exchanger, a throttling device, an air heat exchanger are sequentially connected to form a refrigeration cycle, and a cold and hot water generator in which a water supply port and a tap hole are connected to the water heat exchanger Providing a refrigerant amount adjusting mechanism at an outlet of the water heat exchanger, and adjusting a refrigerant amount circulating in the refrigeration cycle by the refrigerant amount adjusting mechanism according to a boiling temperature target value. apparatus.

2. The cooling / heating water generating device according to claim 1, wherein the refrigerant amount adjusting mechanism sequentially connects a two-way valve and a liquid tank to the outlet of the water heat exchanger, and a capillary in parallel with the two-way valve and the liquid tank. A cold / hot water generator characterized by connecting tubes.

In the cold / hot water generator according to claim 2, when the boiling target temperature is high, the refrigerant is stored in the liquid tank, and when the boiling target temperature is low, the refrigerant is not stored in the liquid tank. A cold / hot water generator.

4. The cold / hot water generator according to claim 2, wherein the liquid tank has a capacity capable of absorbing a difference between a refrigerant amount at which a maximum COP is obtained and a refrigerant amount at which a maximum boiling temperature is obtained. 5. Cold and hot water generator.

The cold / hot water generator according to any one of claims 1 to 4, wherein the amount of refrigerant charged into the refrigeration cycle is an amount at which a maximum COP is obtained.

A refrigeration cycle is configured by connecting a compressor, a four-way valve, a water heat exchanger, a throttle device, and an air heat exchanger in order, with variable capacity, and the water heat exchanger is connected to a water supply port and a tap water port. A method for controlling a cold / hot water generating apparatus, comprising: setting a target superheat amount according to a boiling temperature target value, changing a throttle amount of the throttle device, and controlling a superheat amount. .

In the method for controlling a cold and hot water generator according to claim 6, when the boiling target temperature is low, the target superheat amount constant control is performed, and when the boiling target temperature is high, the discharge temperature constant control is performed. A method for controlling a cold / hot water generator.

The method according to claim 7, wherein when the boiling target temperature is high, the operation is started in a state where the target superheat amount is small, and when the discharge temperature is equal to or higher than a predetermined value, the discharge temperature is increased. A method for controlling a cold / hot water generator, characterized by switching to constant control.

9. The method for controlling a chilled / hot water generator according to claim 6, wherein the target superheat amount is reduced as the boiling target temperature is increased.

The cold / hot water generator according to any one of claims 1 to 5, wherein R410A or R407C is selected as the refrigerant.

The method for controlling a chilled / hot water generator according to any one of claims 6 to 9, wherein R410A or R407C is selected as the refrigerant.