JP2004324902A - Freezing refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a freezing refrigerator for saving energy by improving the efficiency of a cooling cycle during cooling a freezing chamber. <P>SOLUTION: The freezing refrigerator comprises a first evaporator 7 and a second evaporator 9 provided in a refrigerating chamber 2 and in a freezing chamber 3, respectively, a refrigerating chamber cooling cycle 14 having a first condenser 16, a second condenser 17 and the first evaporator 7 in the refrigerating chamber 2, a freezing chamber cooling cycle 15 having the fist condenser 16, a third condenser 20 and the second evaporator 9 in the freezing chamber 3, and a switching means 10 for switching the cooling cycles, the third condenser 20 being arranged in the refrigerating chamber 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００８２】
また、従来の冷凍室冷却サイクルのより詳細な条件を示す。図３の破線で示した従来の冷凍室冷却サイクルにおいてキャピラリ減圧前（ｈ２２）は過冷却を１Ｋとったポイントを示してある。凝縮温度（Ｔ２１）は冷蔵室２と同様に３０度であり、凝縮圧力は０．７７０２ＭＰａとなる。蒸発温度（Ｔ２３）は−２５度であり、蒸発圧力は０．１０６４ＭＰａを示す。圧縮機吸入ポイント（ｈ２４）は蒸発圧力０．１０６４ＭＰａ、温度３０度のポイントを示してある。第二の蒸発器９の出口を飽和蒸気線上のポイント（ｈ２５）とし、圧縮比７．２における圧縮機４での圧縮効率を７７％、機械効率を９０％とする。
【００８３】
また、冷媒の圧力損失を無視すると、この時の冷凍効果は１４３．１ｋＪ／ｋｇであり圧縮仕事は７４．６ｋＪ／ｋｇとなるので、成績係数は１．９２であることがわかる。ここで冷凍室３の負荷量をＱ２（Ｗ）、とし圧縮機４の冷凍室冷却における所要動力をＷ２（Ｗ）とすると、（数２）で表せられる。
【００８４】
【数２】

【００８５】
冷蔵室２の所要動力Ｗ１（Ｗ）と冷凍室３の所要動力Ｗ２（Ｗ）の合計が冷却サイクルの所要動力Ｗ０（Ｗ）となるので、（数１）と（数２）とから、（数３）で表すことができる。
【００８６】
【数３】

【００８７】
よって、断熱箱体の合計負荷量Ｑ０（Ｗ）として冷蔵室負荷量Ｑ１と冷凍室負荷量Ｑ２の比を１：１とすると、従来の冷却サイクルの成績係数は（数４）で求められるように、２．８６となる。
【００８８】
【数４】

【００８９】
同様に本冷却サイクルにおける冷凍室冷却サイクル１５のより詳細な条件を示す。図３の実線で示した冷凍室冷却サイクル１５においてキャピラリ減圧前（ｈ３３）は過冷却を１Ｋとったポイントを示してある。圧縮機吸入ポイント（ｈ２４）は従来と同様に蒸発圧力０．１０６４ＭＰａ、温度３０度のポイントを示してある。これは第二の蒸発器９の出口を飽和蒸気線上のポイント（ｈ２５）とし、また圧縮比３．９における圧縮機４での圧縮効率を８４％、機械効率を９４％としている。
【００９０】
また、冷媒の圧力損失を無視すると、この時の冷凍効果は１７１．２ｋＪ／ｋｇであり圧縮仕事は４３．６ｋＪ／ｋｇとなるので、成績係数は３．９３であることがわかる。
【００９１】
ここで従来と同一負荷量として冷蔵室２の負荷量Ｑ１（Ｗ）、冷凍室３の負荷量をＱ２（Ｗ）とする。圧縮機４の冷凍室冷却サイクル１５における所要動力をＷ２´（Ｗ）とすると、（数５）で表せられる。
【００９２】
【数５】

【００９３】
この時、図３中の（ｈ３２）から（ｈ３３）に至る第二の凝縮器１９の放熱負荷は冷蔵室２の庫内負荷Ｑ３（Ｗ）となる。今、（ｈ３２）を温度２５度のポイントとすると第三の凝縮器２０における放熱の比エンタルピ差は２０６．１ｋＪ／ｋｇとなる。
【００９４】
また、第一の凝縮器１６の放熱比エンタルピ差（ｈ３１）〜（ｈ３２）は３４．４であり、第三の凝縮器１９は第一の凝縮器１６の約６倍以上の放熱能力を必要とすればよい。
【００９５】
ここで冷蔵室２への放熱負荷量Ｑ３（Ｗ）は、冷凍室冷却サイクル１５の冷凍効果と冷凍室負荷量Ｑ２と冷媒循環量Ｇ（ｋｇ／ｈ）から（数６）となり、冷凍室負荷量Ｑ２の１．２倍の負荷量が冷蔵室２に加えられる。これを考慮して圧縮機４の冷蔵室冷却サイクル１４における所要動力Ｗ１´（Ｗ）は、（数７）と表せられる。
【００９６】
【数６】

【００９７】
【数７】

【００９８】
冷蔵室２の所要動力Ｗ１´（Ｗ）と冷凍室３の所要動力Ｗ２´（Ｗ）の合計が冷却サイクルの所要動力Ｗ０´（Ｗ）となるので、（数６）と（数７）とから、（数８）となる。
【００９９】
【数８】

【０１００】
ここで従来と同じく、断熱箱体１の合計負荷量Ｑ０（Ｗ）として冷蔵室負荷量Ｑ１と冷凍室負荷量Ｑ２の比を１：１とすると、本冷却サイクルの成績係数は（数９）で求められるように、３．０８となる。
【０１０１】
【数９】

【０１０２】
以上のように、本実施の形態１の冷凍冷蔵庫は冷蔵室２と冷凍室３を構成する断熱箱体１と、冷蔵室冷却サイクル１４と冷凍室冷却サイクル１５を並列に構成し、切替手段である電動三方弁１０により各サイクルを切替可能としてある。
【０１０３】
また、冷蔵室冷却サイクル１４は圧縮機４と第一の凝縮器１６と切替手段である電動三方弁１０と第二の凝縮器１７と第一のドライヤ１８と第一の減圧手段であるキャピラリ６と第一の蒸発器７と第一のサクションパイプ１９とを環状に接続構成してある。
【０１０４】
さらにまた、冷凍室冷却サイクル１５は圧縮機４と第一の凝縮器１６と電動三方弁１０と第三の凝縮器２０と第二のドライヤ２１と第二の減圧手段であるキャピラリ８と第二の蒸発器９と第二のサクションパイプ２２を環状に接続構成してある。
【０１０５】
また、第二の凝縮器１７は冷蔵室冷却サイクル１４の主要な放熱手段であり、第三の凝縮器２０は冷凍室冷却サイクル１５の主要な放熱手段であり、冷蔵室２庫内に熱交換可能に配置される。
【０１０６】
また一般的に冷却サイクルにはＲ１３４ａやＲ６００ａなどの冷媒が用いられる。さらに、図示しない制御手段と温度検知手段によって、圧縮機４や電動三方弁１０や電動ファン１２、１３等が動作される。
【０１０７】
以上のように構成されるので上記の計算結果が示すように、成績係数を８％向上させることができ、冷蔵庫の消費電力量を削減することができる。
【０１０８】
また、冷凍室冷却サイクル１５の圧縮比が非常に低減されるので、圧縮機４の吐出ガス温度が低減でき、圧縮機４の信頼性向上に効果がある。
【０１０９】
さらに、冷蔵室冷却サイクル１４を高蒸発温度化した場合に圧縮機４の冷凍能力は冷凍室のそれに比べて増加し冷蔵室２の負荷量とのバランスが崩れ、冷却運転時間が非常に短くなり効率の悪い過渡状態で冷却時間が終了するなど効率を低下させてしまう可能性があるが、冷凍室３の放熱負荷を冷蔵室２に転換することで高蒸発温度化に見合った負荷バランスをとることが容易である。
【０１１０】
また、逆止弁１１を設けることにより冷却運転停止中電動三方弁１０を閉止することでサイクルの高低圧を維持しガスカットすることが可能であり、冷媒流入による冷凍室３庫内への熱侵入を低減することができる。
【０１１１】
さらに、本実施の形態１において、冷凍室３の温度設定を一般的な冷凍温度としたが、冷凍保鮮性の向上や急凍のために、冷凍室３温度を通常冷凍温度である−２０℃より低温の、例えば−３０度以下の温度や、特に業務用などで一般的に存在する−４０度の設定を行うなどする場合、従来の冷凍サイクルでは圧縮比は非常に大きくなるが、これを低減することが可能である。この圧縮比の低減により、成績係数の向上ができ消費電力の低減ができる。
【０１１２】
特に圧縮比が１０を超えて大きくなると、圧縮効率や機械効率が大幅に低下してくるので低圧縮比化による効率向上効果は大きい。そして圧縮機４の信頼性が、吐出ガス温度の低減や摺動部の磨耗軽減などの面で向上する。
【０１１３】
また、本実施の形態１において、第一、第二のサクションパイプ１９、２０は各々第一、第二のキャピラリ６，８と、たとえば半田付けや溝つきサクションパイプの溝部にキャピラリを圧接し埋め込むなど熱交換可能に構成することで、キャピラリ通過冷媒の冷却を行い冷凍効果を増加せしめることと、圧縮機４の吸い込みガス温度を周囲温度程度に上昇させ、圧縮機４の吸い込みガスの受熱損失を軽減するとともに、断熱箱体１の外部に配設されたサクションパイプの温度低下による結露、さび付きを防止することを両立するものである。
【０１１４】
特に冷凍室冷却サイクル１５の凝縮温度を大きく低減する場合は熱交換温度差が減少し熱交換量が減少するので、第二のキャピラリ８の代わりに圧縮機４や吐出配管部を含む第一の凝縮器１６などで熱交換を行えば冷凍効果を増加させて成績係数の向上が可能である。
【０１１５】
また、本実施の形態１において、冷蔵室２庫内の第三の凝縮器２０から冷凍室３庫内の第二の蒸発器９までのサイクル構成部品及び接続配管を断熱箱体１のウレタン内に埋設し断熱することにより、冷媒が凝縮後の再加熱による受熱損失を受けて成績係数の低下が生じることを防止する。また、凝縮器出口以降の配管で再加熱によるフラッシュガスの発生を防止することができる。
【０１１６】
また、本実施の形態１において、第二の凝縮器１７は図示しない扉外周部のシール部近傍に配設された結露防止手段、いわゆるドライパイプとして配設するものを含むことにより、冷凍室冷却サイクル１５の配管を配設した場合にくらべて、凝縮温度の低下により結露促進させてしまうことなく防滴が可能であるとともに、冷蔵室冷却運転時だけに放熱パイプの断熱箱体１庫内への熱侵入を抑制できるので消費電力量を低減できる。
【０１１７】
また、本実施の形態１において、断熱箱体１はウレタンを断熱材に使用し、冷蔵室２の負荷量と冷凍室３の負荷量を１：１としているが、（数３）と（数８）から所要動力の計算式においてＱ１の係数は０．１８と等しく、Ｑ２の係数差が所要動力の低減に寄与しているので、冷蔵室２の負荷量Ｑ１が小さいか、もしくは冷凍室３の負荷量Ｑ２が大きければより所要動力の低減が大きくなる。特に冷蔵室外周部に真空断熱材を用いることで、内容積や外容積を犠牲にすることなく負荷量を低減すると、さらに成績係数の向上が見こめる。
【０１１８】
また、本実施の形態１において、冷却サイクルは並列の回路構成により冷蔵室２と冷凍室３とを独立に構成することで各々の部屋の温度影響を受けにくく、冷凍室３庫内にある第二の蒸発器９の低温化や、冷蔵室２庫内にある第一の蒸発器７の高蒸発温度化などに有利であるが、第一の蒸発器７と第二の蒸発器９との直列回路と第二の蒸発器９の単独回路とで構成されたバイパス回路（第一の蒸発器７への冷媒の流れを必要に応じてバイパスさせる）タイプの冷却サイクルにおいても、第二の蒸発器９単独回路における成績係数の向上が可能である。また、上記バイパス回路タイプにおいて、直列接続する第一の蒸発器７と第二の蒸発器９との間に流量制御弁を設けてもよい。この場合、流量制御弁により第一の蒸発器７の蒸発温度を可変でき、第一の蒸発器７と第二の蒸発器９の両方を冷却する状態でも冷蔵室２に適した高蒸発温度設定が可能になり冷蔵室２の湿度を高く保つことができる。
【０１１９】
また、本実施の形態１において、圧縮機４にインバーター能力可変タイプを用いて、冷蔵室冷却運転時の冷凍能力低減を行い、高蒸発温度化における冷凍能力の増加を相殺し抑えることで熱交換器を大幅に能力向上させることなく、大型蒸発器によるスペース効率の低下などを防止できる。
【０１２０】
なお、本実施の形態１において、切替手段は電動三方弁１０としたが、二方弁の組み合わせとしてもよいし、一つの二方弁とキャピラリなどの流路抵抗差によって切り替えてもよい。かつ、電動三方弁１０等の切替手段は、もちろん省エネのためにパルスモーター式の自己保持型であり、バルブ開閉維持のために電力消費をしない。
【０１２１】
また、本実施の形態１においてドライヤ１８，２１は各キャピラリ６，８の前に２個設けたが、いずれか一方でもかまわない。また、電動三方弁１０手前に一つ設けても良く低コスト化が可能であるが、冷媒はガス状態でドライヤを通過するために、圧力損失が大きくなるなどの問題が生じる。さらに、ドライヤ１８，２１をキャピラリ６，８手前に設けない場合はストレーナを設けて、ごみなどを除去するとなお良い。
【０１２２】
また、本実施の形態１において、第三の凝縮器２０の配管径を蒸発器を構成する配管の径よりも小さい配管を用いて構成することで、凝縮器の容量が減少するので冷媒量が低減できる。特にＲ６００ａなどの可燃性冷媒を用いる場合に安全設計にたいして有利となる。細径管には例えば外径４ｍｍ〜３ｍｍの配管で内径３．３ｍｍ〜２．０ｍｍの標準的な配管を選択する。
【０１２３】
（実施の形態２）
図５は本発明による実施の形態２における冷凍冷蔵庫の概略断面図である。
【０１２４】
本実施の形態２は実施の形態１による冷凍冷蔵庫にさらに、第三の凝縮器２０の少なくとも一部が冷蔵室２庫内の冷蔵室ダクト２３内に設けられた第一の蒸発器７と熱交換可能に配設されて構成してある。
【０１２５】
以上ように構成された冷凍冷蔵庫について以下その動作を説明する。
【０１２６】
冷蔵室２は扉開閉や食品の収納などによって生じる水分を冷蔵室冷却サイクル１４の運転時に第一の蒸発器７で冷却する際に除湿する。そのため第一の蒸発器７には着霜が進行する。着霜が進行すると、第一の蒸発器７を通過する空気の風路抵抗が増加し、風量が低下することで冷却能力が低下する。これを防止するために、従来は定期的にヒーターなどで除霜を行っているが、冷凍室冷却サイクル１５運転時に第三の凝縮器２０を第一の蒸発器７と熱交換可能に配設してあるので、ヒーターの代わりに第一の蒸発器７を加熱して除霜を行う。冷却運転は冷蔵室冷却サイクル１４と冷凍室冷却サイクル１５とを並列に構成し交互に切り替えて行うので、第一の蒸発器７の冷却運転（着霜運転）と、第三の凝縮器２０の放熱運転（除霜運転）が同時ではなく、交互に運転を行う。
【０１２７】
以上のように、本実施の形態２の冷凍冷蔵庫は実施の形態１による冷凍冷蔵庫にさらに、第三の凝縮器２０の少なくとも一部分が冷蔵室２庫内の冷蔵室ダクト２３内に設けられた第一の蒸発器７と熱交換可能に設けて構成されてあるので、冷蔵室除霜におけるヒーター入力を削減できる。
【０１２８】
また、第三の凝縮器２０の冷却に潜熱の大きい霜や氷、水の融解・蒸発現象を利用するので、比較的大きな能力を得ることができ、冷凍室冷却サイクル１５の効率をより向上させることが可能である。
【０１２９】
さらにまた、第三の凝縮器２０の放熱による庫内への熱影響を緩和することができる。
【０１３０】
さらに、冷蔵室２庫内の高湿度化をヒーター入力消費せずに行う方法として従来第一の電動ファン１２によってオフサイクル運転（冷蔵室冷却サイクル１４運転停止中のファン運転）を行い庫内空気を循環させて着霜した水分を庫内還元していたが、食品に風速を与えることなく高湿化ができるので一層保鮮性を向上させることが低消費電力でできる。
【０１３１】
なお、本実施の形態２においてはフィンコイルタイプである第一の蒸発器７と第三の凝縮器２０とが各々フィンを共用して配管パスを構成すると、第一の蒸発器７と第三の凝縮器２０の熱伝導がよくなり、除霜及び凝縮器の放熱能力が向上する。また一つの熱交換器を兼用して用いるので低コストに構成でき、工場での部品管理も簡素化できる。
【０１３２】
また、本実施の形態２において、第一の蒸発器７と第三の凝縮器２０の熱交換部に蓄冷材を備えたので冷蔵室冷却サイクル１４の運転中に蓄冷し、冷凍室冷却サイクル１５の運転中に放熱を行うことで、第三の凝縮器２０の放熱能力を向上させるとともに、冷蔵室２庫内への熱影響を低減することができる。
【０１３３】
また、本実施の形態２において第三の凝縮器２０の配管径を比較的細径管とすることで、凝縮器の容量が減少するので冷媒量が低減できる。特にＲ６００ａなどの可燃性冷媒を用いる場合に安全設計にたいして有利となる。細径管には例えば外径４ｍｍ〜３ｍｍの配管で内径３．３ｍｍ〜２．０ｍｍの標準的な配管を選択する。
【０１３４】
（実施の形態３）
図６は本発明による実施の形態３における冷凍冷蔵庫の概略断面図である。
【０１３５】
本実施の形態３は実施の形態１または実施の形態２いずれかによる冷凍冷蔵庫にさらに、第三の凝縮器２０のすくなくとも一部の配管を冷蔵室２庫内の温度補償用の加熱手段２５として、加熱を必要とする部位に熱交換可能に配設する構成としてある。
【０１３６】
なお、加熱手段２５を配設する部位としては、冷凍室３に設けられた図示しない自動製氷装置と冷蔵室２に設けられた給水装置を備え、給水装置水タンクの設置場所の下面もしくは側面に設ける。側面が側壁パネルの場合は側壁パネル断熱材側に加熱手段２５を貼りつけ構成する。これにより給水タンクの凍結防止が容易に行える。
【０１３７】
また、別の加熱手段２５を配設する部位としては冷蔵室２庫内の冷蔵室ダクト２３を構成するダクトパネル２６の背面に当接する。これにより冷蔵室冷却サイクル１４運転時に蒸発器７が低温となって熱伝導によりダクトパネル２６が冷やされ表面結露するのを防止する。
【０１３８】
（実施の形態４）
図７は本発明による実施の形態４における冷凍冷蔵庫の概略断面図である。
本実施の形態４は実施の形態１から実施の形態３のいずれかによる冷凍冷蔵庫にさらに、第三の凝縮器２０のすくなくとも一部の配管を冷蔵室２庫内の蒸発手段２７として、第一の蒸発器７の下方に除霜水を受けるように配設されたドレンパン２８を加熱するようドレンパン２８近傍に配設する。ドレンパン２８から除霜水を断熱箱体１の外部へと放出する経路であるドレンチューブ２９を設け、ドレンチューブ２９の下方で圧縮機４の上方近傍に蒸発皿３０を配置する構成としてある。
【０１３９】
以上のように構成された冷凍冷蔵庫の動作を説明する。
【０１４０】
冷蔵室２は扉開閉や食品の収納などによって生じる水分を冷蔵室冷却サイクル１４の運転時に第一の蒸発器７は着霜する。定期的に除霜することで蒸発器の能力を確保する。除霜時には除霜水が発生し、ドレンパン２８へと流れ込み、ドレンチューブ２９を通り断熱箱体１の外部へと排出される。排出された水は蒸発皿３０に保留される。圧縮機４の運転により蒸発皿３０は暖められるので除霜水は徐々に蒸発していく。一方、ドレンパン２８に霜が落下するなどしてドレンパン２８が凍結することを防止するために従来ヒーターを設けていたが、本実施の形態では、ヒーターの代わりに設けた蒸発手段２７により冷凍室冷却サイクル１５運転時に加熱されるので、従来のように特別なヒーターを必要とせず、低コスト化が図れる。
【０１４１】
以上のように本実施の形態４の冷凍冷蔵庫は、実施の形態１から実施の形態３のいずれかによる冷凍冷蔵庫にさらに、第三の凝縮器２０のすくなくとも一部の配管を冷蔵室２庫内の蒸発手段２７として、第一の蒸発器７の下方に除霜水を受けるように配設されたドレンパン２８を加熱するようドレンパン２８近傍に配設する。ドレンパン２８から除霜水を断熱箱体１の外部へと放出する経路であるドレンチューブ２９を設け、ドレンチューブ２９の下方で圧縮機４の上方近傍に蒸発皿３０を配置する構成としてあるので、ヒーター入力を消費することなくドレンパン２８の温度補償が可能である。
【０１４２】
なお、本実施の形態４においては通常ドレンパン２８を傾斜させてドレンチューブ２９へと排水を促進する構造をとるが、ドレンチューブ２９の開口部より下方に水受けを構成することで除霜水を一旦庫内に保水する。これを蒸発手段２７によって徐々に蒸発させることで恒常的に冷蔵室２の高湿度化が可能である。
【０１４３】
なお、本実施の形態４において、蒸発手段２７はドレンパン２８の上方に除霜水に着水する構成としたが、ドレンパン２８下部に当接して配設することでも同様であり、かつ蒸発手段２７の防錆処理を行わずにすむのでコスト的に有利である。
【０１４４】
また、本実施の形態４において蒸発皿３０は圧縮機４の上方に配置するとしたが、第一の凝縮器１６のすくなくとも一部で構成される配管部を蒸発皿３０に熱交換可能に設けることで、自由度が高くスペース効率のよい蒸発皿の配置が可能となる。
【０１４５】
また、本実施の形態４においてはドレンチューブ２９により断熱箱体１の外部へ除霜水を放出する構成としたが、ドレンパン２８と蒸発手段２７により冷蔵室２庫内で除霜水を保持して蒸発させ、ドレンチューブ２９や、蒸発皿３０を設けない構成とすることで、コスト的に有利であり、また圧縮機４の収納部のスペースを、内容積を大きくしたり、断熱壁を厚くするなど有効に使用することが可能である。
【０１４６】
【発明の効果】
以上説明したように請求項１に記載の発明は、冷蔵室と冷凍室を構成する断熱箱体と、前記冷蔵室庫内に第一の蒸発器と前記冷凍室庫内に第二の蒸発器と、第一の凝縮器と第二の凝縮器と前記第一の蒸発器とを備えた冷蔵室冷却サイクルと、前記第一の凝縮器と第三の凝縮器と前記第二の蒸発器とを備えた冷凍室冷却サイクルと、各冷却サイクルを切り替える切替手段とを設け、前記第三の凝縮器を前記冷蔵室に配設したことを特徴とするものであり、冷凍室冷却サイクル運転時において、従来は凝縮器が周囲温度により熱交換されて放熱するけれども、約０℃〜５℃の庫内温度設定である冷蔵室で第三の凝縮器が放熱するので凝縮温度の一層の低減が可能である。よって低い圧縮比での冷凍室冷却サイクルの運転が可能となり、成績係数の向上が図られる。
【０１４７】
また、冷蔵室の負荷量は凝縮器からの放熱負荷により増加するが、冷蔵室の冷却効率は、比較的高い蒸発温度設定により低圧縮比化が可能であり、冷凍室に比べて成績係数が良いので、消費電力の増加は比較的少なく、総合して冷却サイクルの成績係数が向上し、冷蔵庫の負荷量に対する消費電力量が低減できる。
【０１４８】
また、圧縮比の低減により圧縮機の吐出ガス温度が下がるなど信頼性の向上が可能である冷凍冷蔵庫を提供できる。
【０１４９】
また、請求項２に記載の発明は、請求項１に記載の発明に加え、前記冷凍室庫内温度を通常冷凍温度である−２０℃より低温の温度設定を可能としたことを特徴とするものであり、蒸発温度はより低く設定した場合においても、冷凍室冷却サイクルの圧縮比を大きくすることなく運転可能であり、成績係数を向上することができ、低温冷凍における消費電力量の低減が可能である。また、低蒸発温度における圧縮機の信頼性を向上することが可能である冷凍冷蔵庫を提供できる。
【０１５０】
また、請求項３に記載の発明は、請求項１または請求項２に記載の発明に加えて、前記冷蔵室冷却サイクルは圧縮機と前記第一の凝縮器と前記第二の凝縮器と第一の減圧手段と前記第一の蒸発器と第一のサクションパイプを環状に接続してあり、前記冷凍室冷却サイクルは前記圧縮機と前記第一の凝縮器と前記第三の凝縮器と第二の減圧手段と前記第二の蒸発器と第二のサクションパイプを環状に接続してあり、前記第二のサクションパイプと前記第一の凝縮器とを熱交換可能に配設したことにより、キャピラリ通過冷媒の冷却を行い冷凍効果を増加せしめることと、圧縮機の吸い込みガス温度を周囲温度程度に上昇させ、圧縮機の吸い込みガスの受熱損失を軽減するとともに、断熱箱体の外部に配設されたサクションパイプの温度低下による結露、さび付きを防止することを両立するものである。
【０１５１】
特に冷凍室冷却サイクルの凝縮温度を大きく低減する場合は熱交換温度差が減少し熱交換量が減少するので、温度の高い第一の凝縮器で熱交換を行えば冷凍効果を増加させて成績係数の向上が可能であり、消費電力量の低減が可能である冷凍冷蔵庫を提供できる。
【０１５２】
また、請求項４に記載の発明は、請求項１から請求項３のいずれか一項に記載の発明に加えて、前記第三の凝縮器から前記第二の蒸発器までのサイクル構成部品及び接続配管を前記断熱箱体内に埋設し断熱することにより、断熱箱体外部には配置しないので、冷蔵室で低温に熱交換後は再加熱を防止でき冷却サイクルの成績係数を低下させることがなく、またフラッシュガスの発生を防止することができ信頼性の高い消費電力量を低減した冷凍冷蔵庫を提供できる。
【０１５３】
また、請求項５に記載の発明は、請求項１から請求項４のいずれか一項に記載の発明に加えて、前記第二の凝縮器のすくなくとも一部が前記断熱箱体の開口シール部近傍に配設した結露防止手段としたものであり、冷凍室冷却サイクルの配管を配設した場合にくらべて、凝縮温度の低下により結露促進させてしまうことなく防滴が可能であるとともに、冷蔵室冷却運転時だけに放熱パイプの断熱箱体庫内への熱侵入を抑制できるので冷蔵庫負荷量が低減でき消費電力量を低減可能な冷凍冷蔵庫を提供できる。
【０１５４】
また、請求項６に記載の発明は、請求項１から請求項５のいずれか一項に記載の発明に加えて、前記冷蔵室周囲断熱壁に真空断熱材を用い冷蔵室負荷量を冷凍室負荷量より小さくしたものであり、内容積を減少させたり、外形を大きくすることなく冷蔵室負荷量を低減することができる。そして冷蔵室負荷量と冷凍室負荷量と比べると冷蔵室負荷量が小さくなるので冷凍室冷却サイクルの成績係数改善による消費電力量削減の効果が大きくなり、一層の低消費電力の冷凍冷蔵庫を提供できる。
【０１５５】
また、請求項７に記載の発明は、請求項１から請求項６のいずれか一項に記載の発明に加えて、前記第三の凝縮器の少なくとも一部が前記冷蔵室庫内にある前記第一の蒸発器と熱交換可能に配設したものであり、冷蔵室冷却サイクルの運転により第一の蒸発器に付着した霜の顕熱及び潜熱を利用して、第三の凝縮器と熱交換を行うので、除霜用の加熱手段が不要であり、その加熱に必要な電力を低減可能である。さらに霜の蒸発潜熱は熱量が顕熱に比べてはるかに大きいため、第三の凝縮器の熱交換量も大きくなり、さらに大きな成績係数の向上が可能であり消費電力量を一層低減可能な冷凍冷蔵庫を提供できる。
【０１５６】
また、請求項８に記載の発明は、請求項７に記載の発明に加えて、前記第一の蒸発器と前記第三の凝縮器とがフィンコイルタイプであり、各々フィンを共用して配管パスを構成するものであり、冷蔵室の庫内を冷却するために熱交換面積を増加させるフィンを兼用して凝縮器の熱交換に用いるためにスペース効率が向上するとともに、凝縮器の熱交換面積を増加させるために、さらに大きな成績係数の向上が可能でありかつ兼用により低コストで消費電力量を低減できる冷凍冷蔵庫を提供できる。
【０１５７】
また、請求項９に記載の発明は、請求項７または請求項８のいずれか一項に記載の発明に加えて、前記第一の蒸発器と前記第三の凝縮器の熱交換部に蓄冷材を備えたものであり、冷蔵室冷却時に蓄冷材に蓄えた冷却能力により凝縮器の放熱を行うので大きな能力が得られるとともに、冷蔵室庫内への温度変動影響を低減することができる。
【０１５８】
また、請求項１０に記載の発明は、請求項１から請求項９のいずれか一項に記載の発明に加えて、前記第三の凝縮器は、蒸発器を構成する配管の径よりも小さい配管を用いて構成するものであり、第三の凝縮器の配管下流部には冷媒が液化して存在するので、管内の容積を減少させることで冷却サイクルに必要な冷媒の使用量を低減することが可能となる。特にＲ６００ａなどの可燃性冷媒を用いる場合は安全設計が比較的容易となる。
【０１５９】
また、請求項１１に記載の発明は、請求項１から請求項１０のいずれか一項に記載の発明に加えて、前記第三の凝縮器の少なくとも一部の配管が冷蔵室庫内の温度補償用の加熱手段であり、加熱を必要とする部位に熱交換可能に配設するものであり、庫内電気ヒーターを用いずに凝縮器の放熱により凍結防止や庫内結露防止が可能でありヒーター入力の低減が可能な省エネ冷凍冷蔵庫を提供できる。
【０１６０】
また、請求項１２に記載の発明は、請求項１１記載の発明に加えて、前記冷凍室に自動製氷機と前記冷蔵室に給水装置とを備え、前記給水装置水タンクの凍結防止のために、前記加熱手段を前記水タンク近傍に設けたものであり、庫内電気ヒーターを用いずに凝縮器の放熱により凍結防止や庫内結露防止が可能であり信頼性の高い冷凍冷蔵庫をヒーター入力低減しつつ提供できる。
【０１６１】
また、請求項１３に記載の発明は、請求項１１記載の発明に加えて、前記冷蔵室庫内に冷蔵室ダクトを設けたもので、前記冷蔵室ダクトを構成するダクトパネル背面に前記第三の凝縮器を当接するものであり、庫内電気ヒーターを用いずに凝縮器の放熱により凍結防止や庫内結露防止が可能であり信頼性の高い冷凍冷蔵庫をヒーター入力低減しつつ提供できる。
【０１６２】
また、請求項１４に記載の発明は、請求項１から請求項１１のいずれかに記載の発明に加えて、前記冷蔵室庫内に前記第一の蒸発器からの除霜水を受けるドレンパンと除霜水を外部排出するドレンチューブとを備え、前記第三の凝縮器の少なくとも一部の配管が前記ドレンパンを加熱するよう近傍に配設された蒸発手段としたものであり、第一の蒸発器からドレンパンに落下した霜や除霜水を蒸発促進させて、霜残りやドレン凍結を防止するためのヒーター電力を削減することが可能な省エネ冷凍冷蔵庫を提供できる。
【０１６３】
また、請求項１５に記載の発明は、請求項１４に記載の発明に加えて、前記ドレンパンは前記ドレンチューブの開口部より下方に除霜水を一旦保水する受け構造であり、前記蒸発手段により庫内加湿することを特徴とするので、庫内に食品が少ない状態であっても、ドレンパンに除霜水を保留し、これを凝縮器で加熱するので、凝縮器の能力向上とともに冷蔵室庫内加湿が可能であり、冷蔵室の高湿度化を維持でき、冷蔵室庫内食品の保鮮性を向上する冷凍冷蔵庫を提供できる。
【０１６４】
また、請求項１６に記載の発明は、請求項１から請求項１１のいずれかに記載の発明に加えて、前記ドレンパンと前記蒸発手段により前記冷蔵室庫内で除霜水を保持して蒸発させ、ドレンチューブや、蒸発皿を設けない構成としたものであり、部品点数の削減が可能であり低コストな冷凍冷蔵庫を提供できる。
【図面の簡単な説明】
【図１】本発明の実施の形態１の冷凍冷蔵庫の概略断面図
【図２】同実施の形態の冷凍冷蔵庫の冷蔵室冷却サイクルのモリエル線図
【図３】同実施の形態の冷凍冷蔵庫の冷凍室冷却サイクルのモリエル線図
【図４】同実施の形態の圧縮機効率の特性図
【図５】本発明の実施の形態２の冷凍冷蔵庫の概略断面図
【図６】本発明の実施の形態３の冷凍冷蔵庫の概略断面図
【図７】本発明の実施の形態４の冷凍冷蔵庫の概略断面図
【図８】従来の冷凍冷蔵庫の概略断面図
【符号の説明】
１ 断熱箱体
２ 冷蔵室
３ 冷凍室
４ 圧縮機
６ 第一のキャピラリ
７ 第一の蒸発器
８ 第二のキャピラリ
９ 第二の蒸発器
１０ 電動三方弁
１１ 逆止弁
１２ 第一の電動ファン
１３ 第二の電動ファン
１４ 冷蔵室冷却サイクル
１５ 冷凍室冷却サイクル
１６ 第一の凝縮器
１７ 第二の凝縮器
１９ 第一のサクションパイプ
２０ 第三の凝縮器
２２ 第二のサクションパイプ
２３ 冷蔵室ダクト
２４ 冷凍室ダクト
２５ 加熱手段
２６ ダクトパネル
２７ 蒸発手段
２８ ドレンパン
２９ ドレンチューブ
３０ 蒸発皿[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a refrigerator having a plurality of storage rooms and a plurality of evaporators.
[0002]
[Prior art]
2. Description of the Related Art In recent years, refrigerators have been improved in energy efficiency by independently cooling a refrigerator compartment and a freezer compartment with separate evaporators (for example, see Patent Document 1).
[0003]
Hereinafter, the conventional refrigerator-freezer will be described with reference to the drawings.
[0004]
FIG. 8 shows a schematic sectional view of a conventional cooling cycle and a refrigerator.
[0005]
The heat-insulating box 1 is composed of a refrigerator compartment 2 and a freezer compartment 3, and the object to be cooled such as food is taken in and out by opening and closing a door (not shown) provided in each compartment.
[0006]
In the cooling cycle, the compressor 4, the condenser 5, the first capillary (first decompression means) 6, and the first evaporator 7 provided in the refrigerator compartment 2 are connected in a ring, and the second capillary is connected. (Second depressurizing means) 8 and a second evaporator 9 disposed in the freezer 3 are connected in parallel via an electric three-way valve (switching means) 10 so that the cooling circuit can be switched. A check valve 11 is provided at the outlet pipe of the low-temperature second evaporator 9.
[0007]
A first electric fan (first blowing means) 12 for circulating cool air exchanged with the first evaporator 7 is provided in the refrigerator compartment 2 and a second evaporator is provided in the freezer compartment 3. A second electric fan (second blowing means) 13 for circulating cool air that has exchanged heat with the vessel 9 is provided.
[0008]
The operation of the conventional refrigerator configured as described above will be described below.
[0009]
The operation of the cooling cycle is performed as follows. First, the refrigerant compressed by the compressor 4 is condensed and liquefied in the condenser 5. The condensed refrigerant is decompressed by the first capillary 6 or the second capillary 8, flows into the first evaporator 7 and the second evaporator 9, respectively, is evaporated and vaporized, and then returns to the compressor 4 again. Inhaled.
[0010]
The first fan 12 and the second fan 13 evaporate and evaporate the refrigerant to make the first evaporator 7, the second evaporator 9 and the air in the refrigerating room 2 and the freezing room 3 each of which has a relatively low temperature. Each chamber is cooled by heat exchange and circulation of cool air.
[0011]
The cooling operation of the refrigerator-freezer is performed as follows by temperature detecting means and control means of each room (not shown).
[0012]
When each of the temperature detecting means of the refrigerator compartment 2 and the freezing compartment 3 detects a temperature rise above a predetermined value, the compressor 4 is started, and the cooling cycle is operated until the temperature falls below the predetermined value.
[0013]
When the temperature detecting means of the refrigerating compartment 2 becomes equal to or higher than a predetermined value, the refrigerant flows only into the first evaporator 7 without flowing into the second evaporator 9 by the switching valve 10. The evaporation temperature at this time is 0 to −15 ° C. when the temperature of the refrigerator compartment 2 is set to about 5 ° C., and the coefficient of performance is 2 to 2.5 times the normal evaporation temperature of −25 to −30 ° C. The operation of the compressor is performed.
[0014]
When the temperature detection means of the freezing room 3 becomes equal to or higher than a predetermined value, the refrigerant flows into the second evaporator 9 by the switching valve 10 to cool the freezing room 3. At this time, the evaporating temperature is cooled at a normal evaporating temperature of −25 ° C. to −30 ° C. while the temperature setting of the freezing room is about −20 ° C.
[0015]
As described above, since the refrigerating compartment 2 and the freezing compartment 3 are alternately and repeatedly cooled, the refrigerant is independently circulated to the first evaporator 7 when the refrigerating compartment 2 is cooled, so that the high evaporating temperature (0 to −−) is obtained. 20 ° C.), the compression ratio of the compressor 4 can be reduced, operation is performed with a high coefficient of performance, efficiency is improved, and temperature fluctuation is reduced by reducing the difference between the room temperature and the evaporation temperature of the refrigerator compartment 2. The aim is to reduce the temperature of the refrigerator compartment 2 to reduce the temperature.
[0016]
[Patent Document 1]
JP 11-148761 A
[0017]
[Problems to be solved by the invention]
However, in the above-described conventional configuration, although the efficiency of the cooling cycle has been improved, there is a limit for further improving the efficiency. In particular, since the cooling cycle when cooling the freezing compartment 3 is operated at a relatively low evaporation temperature, the compression ratio is large and the coefficient of performance is inferior to that of the refrigerator compartment 2 cooling operation. The freezing room 3 sets the temperature of the second evaporator 9 at -25 to -30C in order to cool the temperature in the refrigerator to about -20C. Since the temperature difference between the evaporator and the air in the refrigerator is small, there is a limit in the performance of the heat exchanger even when the evaporating temperature is increased to form a cooling cycle with a low compression ratio and a good coefficient of performance.
[0018]
Even in the case where the heat insulating performance of the heat insulating box 1 is improved to pursue energy saving, the temperature difference between the freezing room 3 and the ambient temperature is large because the temperature inside the refrigerator is low, so that the amount of heat passing is reduced. Difficult. Increasing the thickness of the heat insulating wall causes a problem that the internal volume decreases and the outer dimensions of the heat insulating box 1 increase, making it difficult to secure an installation space.
[0019]
Furthermore, the lower the temperature setting of the freezing compartment 3, the lower the temperature of the second evaporator 9 of the freezing compartment 3 must be set, so that the compression ratio increases.
[0020]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, and to improve the efficiency of a cooling cycle at the time of cooling a freezer compartment and to provide an energy-saving refrigerator-freezer.
[0021]
In particular, it is an object of the present invention to improve the efficiency of a cooling cycle in a low-temperature freezer and provide an energy-saving refrigerator.
[0022]
Further, in the conventional refrigerator, since the first evaporator 7 is provided in the refrigerator compartment 2, there is a drawback that the amount of power consumption is increased by using a heating means for defrosting.
[0023]
Another object of the present invention is to reduce power consumption for defrosting a first evaporator provided in a refrigerator.
[0024]
In addition, the conventional refrigerator has a drawback that the temperature of the refrigerator 2 is heated by using a temperature compensation heater to prevent freezing and dew condensation, thereby increasing power consumption.
[0025]
Another object of the present invention is to reduce power consumption for temperature compensation in a refrigerator.
[0026]
Further, in the conventional refrigerator, in order to improve the freshness of the refrigerator compartment 2, the first electric fan 12 of the refrigerator compartment 2 is operated during non-cooling, and the inside of the refrigerator is made using the frosted first evaporator 7. However, there is a disadvantage that sufficient humidification cannot be performed when the amount of frost is small.
[0027]
It is another object of the present invention to provide a refrigerator-freezer which enables high-quality freshness to be maintained by stable humidification of a refrigerator compartment.
[0028]
[Means for Solving the Problems]
The invention according to claim 1 of the present invention is a heat insulating box constituting a refrigerator compartment and a freezer compartment, a first evaporator in the refrigerator compartment and a second evaporator in the refrigerator compartment, A refrigerating compartment cooling cycle including a first condenser, a second condenser, and the first evaporator, including a first condenser, a third condenser, and the second evaporator. And a switching means for switching each cooling cycle, and the third condenser is disposed in the refrigerator compartment.
[0029]
Thus, during the freezing room cooling cycle operation, the third condenser radiates heat in the refrigerator compartment, which is conventionally set at a temperature of about 0 ° C. to 5 ° C., although the condenser conventionally exchanges heat according to the ambient temperature and radiates heat. Therefore, the condensation temperature can be further reduced. Therefore, the freezing room cooling cycle can be operated at a low compression ratio.
[0030]
In addition, the load of the refrigerator compartment increases due to the heat radiation load from the condenser, but the cooling efficiency of the refrigerator compartment can be lowered by setting a relatively high evaporation temperature, and the coefficient of performance is lower than that of the freezer compartment. Since it is good, the increase in power consumption is relatively small, and the effect is that the coefficient of performance of the cooling cycle is improved as a whole.
[0031]
According to a second aspect of the present invention, in addition to the first aspect, the temperature in the freezer compartment can be set at a temperature lower than the normal freezing temperature of −20 ° C. Yes, when the evaporating temperature is set lower, the compression ratio becomes very large in the conventional freezer compartment cooling cycle, and the efficiency coefficient of the compressor is reduced. Has the effect of increasing the coefficient of performance by reducing the compression ratio.
[0032]
According to a third aspect of the present invention, in addition to the first or second aspect, the refrigerating compartment cooling cycle includes a compressor, the first condenser, the second condenser, and a first condenser. The decompression means, the first evaporator, and the first suction pipe are connected in a ring shape, and the freezing room cooling cycle includes the compressor, the first condenser, the third condenser, and the second condenser. The pressure reducing means, the second evaporator, and the second suction pipe are connected in a ring shape, and the second suction pipe and the first condenser are disposed so as to be able to exchange heat. .
[0033]
With the above configuration, the refrigerant passing through the capillary is cooled to increase the refrigerating effect, the temperature of the gas sucked into the compressor is raised to about the ambient temperature, the heat loss of the gas sucked into the compressor is reduced, and the heat insulating box is formed. This prevents both dew condensation and rust due to a decrease in the temperature of the suction pipe disposed outside.
[0034]
In particular, when the condensing temperature in the freezer compartment cooling cycle is greatly reduced, the heat exchange temperature difference decreases and the amount of heat exchange decreases. The coefficient can be improved.
[0035]
According to a fourth aspect of the present invention, in addition to the first aspect of the present invention, a cycle component and a connection pipe from the third condenser to the second evaporator are provided. Since it is characterized in that it is buried in the heat insulation box and insulated, it is not disposed outside the heat insulation box, so it is possible to prevent reheating after heat exchange to a low temperature in the refrigerator compartment and reduce the coefficient of performance of the cooling cycle. Has the effect that there is no.
[0036]
According to a fifth aspect of the present invention, in addition to any one of the first to fourth aspects, at least a part of the second condenser is provided near an opening seal portion of the heat insulating box. Since it is characterized by the arrangement of dew condensation prevention means, it is possible to prevent drip without promoting condensation due to a decrease in condensation temperature, compared to the case where piping for a freezing room cooling cycle is provided, Only during the cooling operation of the refrigerator compartment, it is possible to suppress the heat intrusion of the heat radiating pipe into the insulated box storage, so that the load on the refrigerator can be reduced and the power consumption can be reduced.
[0037]
According to a sixth aspect of the present invention, in addition to the first aspect of the present invention, the load of the refrigerator compartment is reduced by using a vacuum heat insulating material for the heat insulation wall around the refrigerator compartment. Is smaller than the load in the freezer compartment, so that the load in the refrigerator compartment can be reduced without reducing the internal volume or increasing the outer shape. Since the load of the refrigerator compartment is smaller than the load of the refrigerator compartment and the load of the freezer compartment, the effect of reducing the power consumption by improving the coefficient of performance of the freezer compartment cooling cycle is increased.
[0038]
According to a seventh aspect of the present invention, in addition to the first aspect, at least a part of the third condenser is provided in the refrigerator compartment. It is characterized by being arranged so as to be able to exchange heat with the evaporator of the third condenser using the sensible heat and latent heat of the frost attached to the first evaporator by the operation of the refrigerator compartment cooling cycle. Since the heat exchange is performed, there is an effect that a heating unit for defrosting is unnecessary, and power consumption required for the heating can be suppressed.
[0039]
Furthermore, since the latent heat of vaporization of frost has a much larger amount of heat than sensible heat, the amount of heat exchange of the third condenser is also increased, and the effect of further improving the coefficient of performance is possible.
[0040]
Further, even in the refrigerator compartment, exchanging heat with the first evaporator, which has a relatively low temperature, has the effect of increasing the amount of heat exchange.
According to an eighth aspect of the present invention, in addition to the seventh aspect of the present invention, the first evaporator and the third condenser are of a fin coil type, and the fins are shared and the piping path is shared. The fins, which increase the heat exchange area to cool the inside of the refrigerator compartment, are used for the heat exchange of the condenser, so that the space efficiency is improved and the heat of the condenser is improved. In order to increase the exchange area, there is an effect that it is possible to further improve the coefficient of performance.
[0041]
According to a ninth aspect of the present invention, in addition to the seventh aspect of the present invention, a regenerator is provided in a heat exchange part of the first evaporator and the third condenser. The cooling capacity stored in the cold storage material at the time of cooling the refrigerator compartment radiates the heat of the condenser, so that a large capacity can be obtained, and the effect of reducing the temperature fluctuation influence inside the refrigerator compartment can be obtained. Have.
[0042]
According to a tenth aspect of the present invention, in addition to any one of the first to ninth aspects, the third condenser uses a pipe smaller than a diameter of a pipe constituting an evaporator. Since the refrigerant is liquefied downstream of the pipe of the third condenser, the volume of the refrigerant required for the cooling cycle can be reduced by reducing the volume in the pipe. It has the effect that it can be reduced. In particular, when a flammable refrigerant such as R600a is used, safety design becomes relatively easy.
[0043]
According to an eleventh aspect of the present invention, in addition to any one of the first to tenth aspects, at least a part of the pipes of the third condenser is used for temperature compensation in a refrigerator compartment. It is characterized by being arranged so that heat can be exchanged where heat is required, so that freezing and condensation inside the refrigerator can be prevented by radiating heat from the condenser without using an electric heater inside the refrigerator. It has the effect of being.
[0044]
The invention according to claim 12 includes, in addition to the invention according to claim 11, an automatic ice maker in the freezing room and a water supply device in the refrigerator compartment, and the water supply device water tank is prevented from freezing by the water supply device. Since the heating means is provided in the vicinity of the water tank, there is an effect that freezing and dew condensation can be prevented by radiating heat of the condenser without using the electric heater in the refrigerator.
[0045]
According to a thirteenth aspect of the present invention, in addition to the eleventh aspect, a refrigerator compartment duct is provided in the refrigerator compartment, and the third condenser is provided on a rear surface of a duct panel constituting the refrigerator compartment duct. Since it is characterized by contacting the container, it has the effect of preventing freezing and dew condensation inside the refrigerator by radiating heat from the condenser without using the electric heater inside the refrigerator.
[0046]
According to a fourteenth aspect of the present invention, in addition to the first aspect, the drain pan receives defrost water from the first evaporator in the refrigerator compartment and a defroster. A drain tube that discharges water to the outside, wherein at least a part of the piping of the third condenser is an evaporating means disposed in the vicinity so as to heat the drain pan. It has the effect of promoting the evaporation of frost and defrost water that has fallen from the evaporator to the drain pan, thereby reducing heater power for preventing frost residue and drain freezing.
[0047]
According to a fifteenth aspect of the present invention, in addition to the fourteenth aspect, the drain pan has a receiving structure for temporarily holding defrost water below an opening of the drain tube, and is provided inside the refrigerator by the evaporating means. Because it is characterized by humidification, even if there is little food in the refrigerator, the defrost water is retained in the drain pan and heated by the condenser, so the condenser capacity is improved and the refrigerator compartment is humidified. And has an effect that the humidity in the refrigerator compartment can be kept high.
[0048]
According to a sixteenth aspect of the present invention, in addition to any one of the first to eleventh aspects, the drain pan and the evaporating means retain and evaporate defrost water in the refrigerator compartment, Since the drain tube and the evaporating dish are not provided, the number of parts can be reduced.
[0049]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a refrigerator-freezer according to the present invention will be described with reference to the drawings. The same components as those of the related art are denoted by the same reference numerals to avoid duplication, and detailed description is omitted.
[0050]
(Embodiment 1)
FIG. 1 is a schematic sectional view of a refrigerator-freezer according to a first embodiment of the present invention, and FIGS. 2 and 3 are Mollier diagrams of a cooling cycle of the refrigerator-freezer in FIG.
[0051]
A heat insulating box 1 having a heat insulating structure made of urethane or the like includes a refrigerating room 2 and a freezing room 3, and a cooled object such as food is taken in and out by opening and closing a door (not shown) provided in each room. The refrigerator compartment 2 may be further subdivided into a refrigerator compartment, a vegetable compartment, a bottle compartment, and a new temperature zone compartment (partial compartment, chilled compartment, etc.). In addition, the freezing room 3 includes an automatic ice maker, and may be subdivided into an ice making room and a switching room in which a user can set a temperature zone.
[0052]
Doors made of heat-insulating material (not shown) can be rotated and opened or pulled out, and the doors can be opened and closed. In some cases, a drawer-storable basket is arranged in a multi-stage so as to be able to be separately stored inside the door. In the case of the drawer type, usually, a basket for storing food is held by the door, and the basket is pulled out by the door withdrawing operation.
[0053]
The abutting portion between the heat-insulating door and the heat-insulating box is sealed by a packing provided along the outer periphery of the door (not shown) to prevent cold air leakage.
[0054]
In the cooling cycle, a refrigerating compartment cooling cycle 14 and a freezing compartment cooling cycle 15 are configured in parallel, and each cycle can be switched by an electric three-way valve 10 as a switching means.
[0055]
The refrigerating compartment cooling cycle 14 includes a compressor 4, a first condenser 16, an electric three-way valve 10 as switching means, a second condenser 17, a first dryer 18, and a capillary 6 as first pressure reducing means. And the first evaporator 7 and the first suction pipe 19 are connected in a ring shape.
[0056]
The freezing room cooling cycle 15 includes a compressor 4, a first condenser 16, an electric three-way valve 10, a third condenser 20, a second dryer 21, a capillary 8 as a second pressure reducing means, and a second condenser 21. The evaporator 9 and the second suction pipe 22 are connected in a ring shape. On the way, the second suction pipe 22 is provided with the check valve 11 just before the junction with the first suction pipe 19.
[0057]
Inside the refrigerator compartment 2, a first electric fan (first blowing means) 12 for circulating the cold air exchanged with the first evaporator 7 and the first evaporator 7 are placed in a refrigerator compartment duct 23 forming an air passage. In the same manner as the second electric fan (second blowing means) 13 for circulating cool air exchanged with the second evaporator 9 in the freezer compartment 3, it is provided with freezing in the freezer compartment 3. It is provided in the chamber duct 24. As the electric fans 12, 13, an axial fan, a sirocco fan, a cross flow fan, or the like is used.
[0058]
The second condenser 17 is a main heat radiating means of the refrigerating room cooling cycle 14, and heat exchanges with a forced air cooling type using an electric fan (not shown) provided outside the heat insulating box 1, and heat exchange with the heat insulating box outer peripheral wall panel. A natural air-cooled type in which piping is arranged as much as possible, or a combination thereof is used.
[0059]
The third condenser 20 is a main heat radiating means of the freezing room cooling cycle 15 and is arranged in the refrigerator compartment 2 so as to be able to exchange heat. Considering the effect of heat radiation on the temperature inside the refrigerator, it is desirable to provide it in the refrigerator compartment duct 21.
[0060]
Generally, a refrigerant such as R134a or R600a is used in the cooling cycle.
[0061]
Further, the compressor 4, the electric three-way valve 10, the electric fans 12, 13 and the like are operated by a control means and a temperature detecting means (not shown).
[0062]
The operation of the refrigerator-freezer configured as described above will be described below.
[0063]
FIG. 2 is a Mollier chart of the refrigerator compartment cooling cycle, and FIG. 4 is a chart showing an example of the compression efficiency and mechanical efficiency of the compressor.
[0064]
The cooling of each room is performed by alternately switching the cooling of the refrigerating room 2 and the cooling of the freezing room 3 by a control means (not shown) and a temperature detecting means provided in each room. The internal cooling of the refrigerator compartment 2 and the freezer compartment 3 is performed by cooling the first evaporator 7 and the second evaporator 9 and the air in the refrigerator compartment 2 and the freezer compartment 3 which have become relatively low in temperature by the operation of the cooling cycle. The heat is exchanged by the electric fan 12 and the second electric fan 13 to circulate cool air.
[0065]
The operation of the cooling cycle includes the operation of the refrigerator compartment cooling cycle 14 and the operation of the freezer compartment operation cycle 15, and is performed as follows. The points in parentheses indicate points on the Mollier diagram. In the operation of the refrigerating compartment cooling cycle 14, the refrigerant (h11) compressed by the compressor 4 is radiated by the first condenser 16. The radiated refrigerant is condensed and liquefied in the second condenser 17 by selecting a cooling circuit in the electric three-way valve 10. The liquefied refrigerant is supplied to the first capillary 6 after the impurities such as residual moisture and dust are removed by the first dryer 18 (h12). The refrigerant decompressed by the first capillary 6 flows into the first evaporator 7 (h13), and evaporates and evaporates by exchanging heat with the air in the refrigerator compartment 2. The vaporized refrigerant passes through the first suction pipe 19, returns to the compressor 4 (h14), and is discharged again (h11).
[0066]
Assuming that the compression work of the compressor 4 is theoretically an isentropic change, the discharge point is (h16). However, the efficiency of the compressor 4 decreases due to the pressure drop of the discharge valve and the suction valve, the gas leakage between the piston and the cylinder, and the loss due to heat reception. Generally, a reduction in efficiency due to these losses is represented by compression efficiency. Further, the efficiency is further reduced due to mechanical loss such as friction of each sliding portion of the compressor 4. Generally, the efficiency reduction due to these losses is represented by mechanical efficiency. As an example, as shown in FIG. 4, these efficiencies generally decrease as the compression ratio increases.
[0067]
The actual compression work is calculated by adding the compression efficiency and the mechanical efficiency to the theoretical compression work in consideration of the above-mentioned efficiency reduction. On the Mollier diagram, the specific enthalpy increases from the theoretical compressor discharge point (h16) (h11).
[0068]
At this time, for example, assuming that the ambient temperature of the heat insulating box 1 is 25 degrees, the condensing temperature (T11) of the recent energy-saving refrigerator is reduced to about 30 degrees with a temperature difference of about 5K. Assuming that the evaporating temperature (T12) is, for example, 0 degree with a temperature difference of about 5K with respect to the inside temperature of the refrigerator compartment 2 of 5 degrees, at this time, if the refrigerant is R134a, the condensing pressure is 0. It becomes 7702 MPa, the evaporation pressure becomes 0.2928 MPa, and the compression ratio is calculated to be about 2.6. Actually, the compression ratio is slightly higher because the pressure loss is caused by the flow path resistance in the pipe.
[0069]
Since the coefficient of performance is indicated by the ratio of the refrigerating effect to the compression work, the larger the refrigerating effect and the smaller the compression work, the higher the coefficient of performance. On the Mollier diagram, the refrigeration effect represents the specific enthalpy difference from the inlet to the outlet of the evaporator, and the compression work is represented by the specific enthalpy difference from the suction to the discharge of the compressor.Therefore, the smaller the compression ratio, the smaller the compression work. The coefficient of performance improves. Further, as the compression ratio is smaller, the compression efficiency and mechanical efficiency of the compressor 4 are improved, and the compression work is smaller, so that the coefficient of performance is improved.
[0070]
On the other hand, FIG. 3 shows a Mollier diagram of the freezing room cooling cycle 15, and a broken line in the figure shows a Mollier diagram of the conventional freezing room cooling cycle for comparison.
[0071]
The operation of the freezer compartment cooling cycle 15 is the same as that of the refrigerator compartment cooling cycle 14 until the refrigerant compressed by the compressor 4 (h31) is radiated by the first condenser 16 (h32), but the electric three-way valve At 10, the cooling circuit is selected for refrigeration, and the refrigerant is supplied to the third condenser 20. The third condenser 20 is disposed so as to be able to exchange heat with the temperature in the refrigerator compartment 2. The refrigerant is condensed and liquefied and supplied to the second capillary 8 through the second dryer 21 (h33). ).
[0072]
The refrigerant decompressed by the second capillary 8 flows into the second evaporator 9 (h34), and evaporates and evaporates by exchanging heat with air in the freezer compartment 3. After passing through the second suction pipe 22, the evaporated refrigerant returns to the compressor 4 via a junction with the first suction pipe 19 (h35), and is discharged again (h31). A check valve 11 is provided on the second suction pipe 22 on the way to prevent a backflow from the refrigerator compartment cooling cycle 14 during the refrigerator compartment cooling operation.
[0073]
The first and second suction pipes 19 and 22 are constituted by pipes having a relatively large inner diameter to reduce low pressure loss.
[0074]
At this time, for example, assuming that the ambient temperature of the heat insulating box 1 is 25 degrees, the condensing temperature (T21) of the recent energy-saving refrigerator is reduced to about 30 degrees with a temperature difference of about 5K. Assuming that the evaporation temperature (T23) is, for example, -25 degrees with respect to the inside temperature of the cold building room 3 of about -20 degrees, at this time, if the refrigerant is R134a, the condensing pressure is 0.7702 MPa from the pressure corresponding to each saturation temperature. , The evaporation pressure becomes 0.1064 MPa, and the compression ratio is calculated to be about 7.2.
[0075]
However, according to the first embodiment, heat is dissipated in the first condenser 16 to an ambient temperature of about 25 degrees (h32), and thereafter, heat is exchanged with the refrigerator compartment 2 in the third condenser 20, The condensing temperature (T22) condenses and liquefies the refrigerant at a temperature difference of about 5K from the temperature in the refrigerator at about 10 degrees.
[0076]
At this time, the compression ratio of the freezing room cooling cycle 15 is calculated to be about 3.9 from the condensing pressure of 0.4146 MPa and the evaporating pressure of 0.1064 MPa.
[0077]
However, on the other hand, since the heat radiation load of the freezer compartment 3 is added as the load of the refrigerator compartment 2, improvement of the coefficient of performance must take this into consideration.
[0078]
Hereinafter, the calculation of the coefficient of performance of the present cooling system will be described with reference to the Mollier diagrams of FIGS.
[0079]
First, a conventional cooling cycle is calculated. 2 shows more detailed conditions of a conventional refrigerator compartment cooling cycle. Before the capillary decompression (h12) in the refrigerator compartment cooling cycle 14 in FIG. 2, the point at which the supercooling is set to 1K is shown. The compressor suction point (h14) indicates a point where the evaporation pressure is 0.2928 MPa and the temperature is 30 degrees. The outlet of the first evaporator 7 is set to a point (h15) on the saturated vapor line, and the compression efficiency in the compressor 4 at the compression ratio of 2.6 is 85% and the mechanical efficiency is 95%.
[0080]
Also, ignoring the pressure loss of the refrigerant, the refrigerating effect at this time is 158.3 kJ / kg and the compression work is 28.6 kJ / kg, so that the coefficient of performance is 5.53. Here, assuming that the load amount of the refrigerator compartment 2 is Q1 (W) and the required power of the compressor 4 in the conventional refrigerator compartment cooling cycle is W1 (W), it is represented by (Equation 1).
[0081]
(Equation 1)

[0082]
Further, more detailed conditions of the conventional freezing room cooling cycle will be described. In the conventional freezing room cooling cycle shown by the broken line in FIG. 3, before the capillary decompression (h22), a point at which the supercooling is set to 1K is shown. The condensing temperature (T21) is 30 degrees like the refrigerating room 2, and the condensing pressure is 0.7702 MPa. The evaporation temperature (T23) is −25 degrees, and the evaporation pressure indicates 0.1064 MPa. The compressor suction point (h24) indicates a point at an evaporation pressure of 0.1064 MPa and a temperature of 30 degrees. The outlet of the second evaporator 9 is set to a point (h25) on the saturated vapor line, and the compression efficiency of the compressor 4 at a compression ratio of 7.2 is 77% and the mechanical efficiency is 90%.
[0083]
If the pressure loss of the refrigerant is neglected, the refrigerating effect at this time is 143.1 kJ / kg and the compression work is 74.6 kJ / kg, so that the coefficient of performance is 1.92. Here, assuming that the load amount of the freezing compartment 3 is Q2 (W) and the required power for cooling the freezing compartment of the compressor 4 is W2 (W), it can be expressed by (Equation 2).
[0084]
(Equation 2)

[0085]
Since the sum of the required power W1 (W) of the refrigerating compartment 2 and the required power W2 (W) of the freezing compartment 3 is the required power W0 (W) of the cooling cycle, (Equation 1) and (Equation 2) give It can be expressed by Equation 3).
[0086]
[Equation 3]

[0087]
Therefore, assuming that the ratio of the load of the refrigerator compartment Q1 to the load of the freezer compartment Q2 is 1: 1 as the total load Q0 (W) of the heat insulating box, the coefficient of performance of the conventional cooling cycle can be obtained by (Equation 4). Is 2.86.
[0088]
(Equation 4)

[0089]
Similarly, more detailed conditions of the freezing room cooling cycle 15 in the present cooling cycle will be described. In the freezing room cooling cycle 15 shown by the solid line in FIG. 3, before the capillary decompression (h33), a point at which the supercooling is set to 1K is shown. The compressor suction point (h24) indicates a point at an evaporation pressure of 0.1064 MPa and a temperature of 30 degrees, as in the conventional case. This means that the outlet of the second evaporator 9 is set at a point (h25) on the saturated vapor line, and the compression efficiency of the compressor 4 at the compression ratio of 3.9 is 84% and the mechanical efficiency is 94%.
[0090]
Also, ignoring the pressure loss of the refrigerant, the refrigerating effect at this time is 171.2 kJ / kg and the compression work is 43.6 kJ / kg, so that the coefficient of performance is 3.93.
[0091]
Here, it is assumed that the load amount of the refrigerator compartment 2 is Q1 (W) and the load amount of the freezer compartment 3 is Q2 (W) as the same load amount as in the related art. Assuming that the required power in the freezing room cooling cycle 15 of the compressor 4 is W2 ′ (W), it is expressed by (Equation 5).
[0092]
(Equation 5)

[0093]
At this time, the heat radiation load of the second condenser 19 from (h32) to (h33) in FIG. 3 is the load Q3 (W) in the refrigerator 2. Now, assuming that (h32) is a point at a temperature of 25 degrees, the specific enthalpy difference of heat radiation in the third condenser 20 is 206.1 kJ / kg.
[0094]
In addition, the heat radiation ratio enthalpy differences (h31) to (h32) of the first condenser 16 are 34.4, and the third condenser 19 needs a heat radiation capacity that is about six times or more that of the first condenser 16. And it is sufficient.
[0095]
Here, the heat radiation load amount Q3 (W) to the refrigerator compartment 2 becomes (Equation 6) from the refrigerating effect of the refrigerator compartment cooling cycle 15, the refrigerator compartment load Q2 and the refrigerant circulation amount G (kg / h), and A load of 1.2 times the amount Q2 is applied to the refrigerator compartment 2. Taking this into consideration, the required power W1 '(W) in the refrigerator compartment cooling cycle 14 of the compressor 4 is expressed by (Equation 7).
[0096]
(Equation 6)

[0097]
(Equation 7)

[0098]
Since the sum of the required power W1 '(W) of the refrigerator compartment 2 and the required power W2' (W) of the freezer compartment 3 is the required power W0 '(W) of the cooling cycle, (Equation 6) and (Equation 7) are obtained. , (Equation 8).
[0099]
(Equation 8)

[0100]
Here, if the ratio of the load Q1 of the refrigerator compartment to the load Q2 of the freezer compartment is set to 1: 1 as the total load Q0 (W) of the heat insulating box 1, the coefficient of performance of this cooling cycle is (Equation 9). Is 3.08, as determined by
[0101]
(Equation 9)

[0102]
As described above, the refrigerator-freezer of the first embodiment includes the heat-insulating box 1 forming the refrigerator compartment 2 and the refrigerator compartment 3, the refrigerator cooling cycle 14, and the refrigerator cooling cycle 15 arranged in parallel. Each cycle can be switched by a certain electric three-way valve 10.
[0103]
The refrigerating compartment cooling cycle 14 includes a compressor 4, a first condenser 16, an electric three-way valve 10 as switching means, a second condenser 17, a first dryer 18, and a capillary 6 as first pressure reducing means. And the first evaporator 7 and the first suction pipe 19 are connected in a ring shape.
[0104]
Furthermore, the freezer compartment cooling cycle 15 includes the compressor 4, the first condenser 16, the electric three-way valve 10, the third condenser 20, the second dryer 21, the second decompression means capillary 8, and the second decompression means. And the second suction pipe 22 are annularly connected.
[0105]
The second condenser 17 is a main radiator of the refrigerator compartment cooling cycle 14, and the third condenser 20 is a main radiator of the refrigerator compartment cooling cycle 15. It is arranged as possible.
[0106]
Generally, a refrigerant such as R134a or R600a is used in the cooling cycle. Further, the compressor 4, the electric three-way valve 10, the electric fans 12, 13 and the like are operated by a control means and a temperature detecting means (not shown).
[0107]
With the above configuration, the coefficient of performance can be improved by 8% as shown by the above calculation results, and the power consumption of the refrigerator can be reduced.
[0108]
Further, since the compression ratio of the freezing room cooling cycle 15 is significantly reduced, the temperature of the discharge gas of the compressor 4 can be reduced, which is effective in improving the reliability of the compressor 4.
[0109]
Further, when the temperature of the refrigerating compartment cooling cycle 14 is raised to a high evaporating temperature, the refrigerating capacity of the compressor 4 increases as compared with that of the refrigerating compartment, the balance with the load of the refrigerating compartment 2 is lost, and the cooling operation time becomes extremely short. Although there is a possibility that the cooling time ends in an inefficient transient state, the efficiency may be reduced. However, by switching the heat radiation load of the freezing room 3 to the refrigerating room 2, a load balance appropriate for the high evaporation temperature is obtained. It is easy.
[0110]
In addition, by providing the check valve 11, by closing the electric three-way valve 10 while the cooling operation is stopped, it is possible to maintain the high and low pressures of the cycle and cut off the gas. Intrusion can be reduced.
[0111]
Further, in the first embodiment, the temperature of the freezing compartment 3 is set to a general freezing temperature. However, the freezing compartment 3 is set to a normal freezing temperature of −20 ° C. in order to improve the freezing and freshness and to rapidly freeze. In the case of setting a lower temperature, for example, a temperature of -30 degrees or less, and especially a setting of -40 degrees, which is generally present in business use, the compression ratio becomes very large in the conventional refrigeration cycle. It is possible to reduce. By reducing the compression ratio, the coefficient of performance can be improved and the power consumption can be reduced.
[0112]
In particular, when the compression ratio exceeds 10 and becomes large, the compression efficiency and the mechanical efficiency are greatly reduced, and the effect of improving the efficiency by reducing the compression ratio is great. Further, the reliability of the compressor 4 is improved in terms of reduction of the discharge gas temperature and reduction of abrasion of the sliding portion.
[0113]
Also, in the first embodiment, the first and second suction pipes 19 and 20 are respectively buried by pressing and contacting the first and second capillaries 6 and 8 with, for example, grooves of the suction pipe with soldering or grooves. Such a configuration that allows heat exchange enables cooling of the refrigerant passing through the capillary to increase the refrigeration effect, and raises the temperature of the suction gas of the compressor 4 to about the ambient temperature, thereby reducing the heat loss of the suction gas of the compressor 4. In addition to reducing the temperature, it is possible to prevent condensation and rust due to a decrease in the temperature of the suction pipe disposed outside the heat-insulating box 1.
[0114]
In particular, when the condensation temperature of the freezing room cooling cycle 15 is greatly reduced, the heat exchange temperature difference is reduced and the heat exchange amount is reduced. Therefore, the first capillary including the compressor 4 and the discharge pipe section instead of the second capillary 8 is used. If heat exchange is performed in the condenser 16 or the like, the refrigeration effect can be increased and the coefficient of performance can be improved.
[0115]
In the first embodiment, the cycle components and connection pipes from the third condenser 20 in the refrigerator compartment 2 to the second evaporator 9 in the freezer compartment 3 are connected to the urethane of the heat-insulating box 1. By being buried in the heat insulation, it is possible to prevent the refrigerant from receiving the heat loss due to the reheating after the condensation, thereby lowering the coefficient of performance. Further, it is possible to prevent the generation of flash gas due to reheating in the piping after the condenser outlet.
[0116]
Further, in the first embodiment, the second condenser 17 includes a dew condensation preventing means disposed near the seal portion on the outer peripheral portion of the door (not shown), that is, a second condenser 17 disposed as a so-called dry pipe, thereby cooling the freezer compartment. Compared to the case where the piping of the cycle 15 is provided, drip-proofing is possible without promoting dew condensation due to a decrease in the condensation temperature, and the heat radiation pipes are inserted into the heat-insulating box 1 only during the cooling operation of the refrigerator compartment. Power consumption can be reduced because the heat intrusion can be suppressed.
[0117]
Further, in the first embodiment, the heat insulating box 1 uses urethane as a heat insulating material, and the load of the refrigerator compartment 2 and the load of the freezer compartment 3 are 1: 1. 8), the coefficient of Q1 is equal to 0.18 in the calculation formula of the required power, and the coefficient difference of Q2 contributes to the reduction of the required power. Therefore, the load Q1 of the refrigerator compartment 2 is small or the freezer compartment 3 , The required power is more greatly reduced. In particular, by using a vacuum heat insulating material on the outer periphery of the refrigerator compartment to reduce the load without sacrificing the internal volume or the external volume, it is possible to further improve the coefficient of performance.
[0118]
In the first embodiment, the cooling cycle is configured such that the refrigerating compartment 2 and the freezing compartment 3 are independently configured by a parallel circuit configuration, so that the cooling cycle is hardly affected by the temperature of each compartment. This is advantageous for lowering the temperature of the second evaporator 9 and increasing the temperature of the first evaporator 7 in the refrigerator compartment 2. Even in a cooling circuit of a bypass circuit type (by which the flow of the refrigerant to the first evaporator 7 is bypassed as necessary) composed of a series circuit and a single circuit of the second evaporator 9, the second evaporation It is possible to improve the coefficient of performance in the single circuit of the device 9. In the bypass circuit type, a flow control valve may be provided between the first evaporator 7 and the second evaporator 9 connected in series. In this case, the evaporating temperature of the first evaporator 7 can be varied by the flow control valve, and even when both the first evaporator 7 and the second evaporator 9 are cooled, a high evaporating temperature setting suitable for the refrigerator compartment 2 can be achieved. And the humidity of the refrigerator compartment 2 can be kept high.
[0119]
In the first embodiment, the compressor 4 is of a variable inverter capacity type to reduce the refrigerating capacity during the cooling operation of the refrigerator and to offset the increase in the refrigerating capacity at a high evaporation temperature to thereby suppress heat exchange. It is possible to prevent a reduction in space efficiency due to a large evaporator without significantly improving the capacity of the vessel.
[0120]
In the first embodiment, the switching means is the electric three-way valve 10. However, the switching means may be a combination of two-way valves, or may be switched by one two-way valve and a flow path resistance difference of a capillary or the like. The switching means such as the electric three-way valve 10 is of a pulse motor type self-holding type for energy saving, and does not consume power for maintaining the opening and closing of the valve.
[0121]
In the first embodiment, two dryers 18 and 21 are provided in front of the capillaries 6 and 8, however, either one may be used. Further, one may be provided in front of the electric three-way valve 10 to reduce the cost. However, since the refrigerant passes through the dryer in a gaseous state, a problem such as an increase in pressure loss occurs. Further, when the dryers 18 and 21 are not provided in front of the capillaries 6 and 8, it is more preferable to provide a strainer to remove dust and the like.
[0122]
Further, in the first embodiment, by configuring the pipe diameter of the third condenser 20 using a pipe smaller than the diameter of the pipe constituting the evaporator, the capacity of the condenser is reduced, so that the refrigerant amount is reduced. Can be reduced. In particular, when a flammable refrigerant such as R600a is used, it is advantageous for safety design. For the small diameter pipe, for example, a standard pipe having an outer diameter of 4 mm to 3 mm and an inner diameter of 3.3 mm to 2.0 mm is selected.
[0123]
(Embodiment 2)
FIG. 5 is a schematic sectional view of a refrigerator-freezer according to Embodiment 2 of the present invention.
[0124]
The second embodiment differs from the refrigerator-freezer according to the first embodiment in that at least a part of the third condenser 20 is connected to the first evaporator 7 provided in the refrigerator compartment duct 23 in the refrigerator compartment 2 and heat. It is arranged so as to be exchangeable.
[0125]
The operation of the refrigerator having the above-described structure will be described below.
[0126]
The refrigerating compartment 2 dehumidifies the moisture generated by opening and closing the door and storing the food when the first evaporator 7 cools the moisture during the operation of the refrigerating compartment cooling cycle 14. Therefore, frost formation progresses on the first evaporator 7. As the frost formation progresses, the resistance of the air passing through the first evaporator 7 increases, and the cooling capacity decreases due to a decrease in the air volume. In order to prevent this, conventionally, defrosting is periodically performed by a heater or the like, but the third condenser 20 is disposed so as to be able to exchange heat with the first evaporator 7 when the freezing room cooling cycle 15 is operated. Therefore, instead of the heater, the first evaporator 7 is heated to perform defrosting. The cooling operation is performed by alternately switching the refrigerating room cooling cycle 14 and the freezing room cooling cycle 15 in parallel and performing the cooling operation (frosting operation) of the first evaporator 7 and the cooling operation of the third condenser 20. The heat dissipation operation (defrosting operation) is performed not alternately but alternately.
[0127]
As described above, the refrigerator-freezer according to the second embodiment is different from the refrigerator-freezer according to the first embodiment in that at least a part of the third condenser 20 is provided in the refrigerator compartment duct 23 in the refrigerator compartment 2. Since it is provided so as to be able to exchange heat with one evaporator 7, it is possible to reduce the heater input in the defrosting of the refrigerator compartment.
[0128]
Further, since the melting and evaporation of frost, ice and water having a large latent heat is used for cooling the third condenser 20, a relatively large capacity can be obtained, and the efficiency of the freezing room cooling cycle 15 is further improved. It is possible.
[0129]
Furthermore, the influence of heat on the inside of the refrigerator due to the heat radiation of the third condenser 20 can be reduced.
[0130]
Further, as a method for increasing the humidity in the refrigerator compartment 2 without consuming the heater input, off-cycle operation (fan operation while the refrigerator compartment cooling cycle 14 is stopped) is performed by the conventional first electric fan 12 and air inside the refrigerator compartment is controlled. The frost is circulated to reduce the frosted water in the refrigerator, but the food can be humidified without giving a wind speed, so that the freshness can be further improved with low power consumption.
[0131]
In the second embodiment, when the first evaporator 7 and the third condenser 20 of the fin coil type share a fin to form a piping path, the first evaporator 7 and the third The heat conduction of the condenser 20 is improved, and the defrosting and the heat radiation performance of the condenser are improved. In addition, since one heat exchanger is also used, it can be configured at a low cost, and parts management in a factory can be simplified.
[0132]
Further, in the second embodiment, since the regenerator is provided in the heat exchanging section of the first evaporator 7 and the third condenser 20, the regenerative storage is performed during the operation of the refrigerating compartment cooling cycle 14, and the refrigerating compartment cooling cycle 15 By radiating heat during the operation, the heat radiation capability of the third condenser 20 can be improved, and the influence of heat on the inside of the refrigerator compartment 2 can be reduced.
[0133]
Further, in the second embodiment, by setting the pipe diameter of the third condenser 20 to a relatively small diameter pipe, the capacity of the condenser is reduced, so that the refrigerant amount can be reduced. In particular, when a flammable refrigerant such as R600a is used, it is advantageous for safety design. For the small diameter pipe, for example, a standard pipe having an outer diameter of 4 mm to 3 mm and an inner diameter of 3.3 mm to 2.0 mm is selected.
[0134]
(Embodiment 3)
FIG. 6 is a schematic sectional view of a refrigerator-freezer according to Embodiment 3 of the present invention.
[0135]
Embodiment 3 is different from the refrigerator-freezer according to Embodiment 1 or Embodiment 2 in that at least a part of the piping of the third condenser 20 is used as a heating means 25 for temperature compensation in the refrigerator compartment 2. , And is arranged so as to be able to exchange heat at a portion requiring heating.
[0136]
The heating unit 25 is provided with an automatic ice making device (not shown) provided in the freezer compartment 3 and a water supply device provided in the refrigerator compartment 2. Provide. When the side surface is a side wall panel, the heating means 25 is attached to the side wall panel heat insulating material side. This makes it possible to easily prevent the water supply tank from freezing.
[0137]
In addition, as a portion where another heating means 25 is disposed, it comes into contact with the back surface of a duct panel 26 constituting the refrigerator compartment duct 23 in the refrigerator compartment 2. This prevents the evaporator 7 from being cooled to a low temperature during the operation of the refrigerating compartment cooling cycle 14, thereby preventing the duct panel 26 from being cooled by heat conduction and dew condensation on the surface.
[0138]
(Embodiment 4)
FIG. 7 is a schematic sectional view of a refrigerator-freezer according to Embodiment 4 of the present invention.
Embodiment 4 is different from the refrigerator-freezer according to any of Embodiments 1 to 3 in that at least a part of the piping of the third condenser 20 is used as the evaporating means 27 in the refrigerator compartment 2. Is disposed in the vicinity of the drain pan 28 so as to heat the drain pan 28 disposed below the evaporator 7 so as to receive the defrost water. A drain tube 29 which is a path for discharging defrost water from the drain pan 28 to the outside of the heat insulating box 1 is provided, and an evaporating dish 30 is disposed below the drain tube 29 and near the upper portion of the compressor 4.
[0139]
The operation of the refrigerator-freezer configured as described above will be described.
[0140]
In the refrigerator compartment 2, the first evaporator 7 frosts moisture generated by opening and closing the door and storing foods during the operation of the refrigerator compartment cooling cycle 14. Periodically defrost to ensure evaporator capacity. During defrosting, defrosting water is generated, flows into the drain pan 28, and is discharged to the outside of the heat insulating box 1 through the drain tube 29. The discharged water is retained in the evaporating dish 30. Since the evaporating dish 30 is warmed by the operation of the compressor 4, the defrost water evaporates gradually. On the other hand, a heater is conventionally provided to prevent the drain pan 28 from freezing due to frost falling on the drain pan 28, but in the present embodiment, the freezing chamber is cooled by the evaporating means 27 provided instead of the heater. Since heating is performed during the operation of the cycle 15, a special heater is not required unlike the related art, and the cost can be reduced.
[0141]
As described above, the refrigerator-freezer of the fourth embodiment differs from the refrigerator-freezer of any one of the first to third embodiments in that at least a part of the piping of the third condenser 20 is connected to the refrigerator compartment 2. Is disposed near the drain pan 28 so as to heat a drain pan 28 disposed below the first evaporator 7 so as to receive defrost water. Since a drain tube 29 which is a path for discharging defrost water from the drain pan 28 to the outside of the heat insulating box 1 is provided, and the evaporating dish 30 is arranged below the drain tube 29 and near the upper part of the compressor 4, The temperature of the drain pan 28 can be compensated without consuming the heater input.
[0142]
In the fourth embodiment, the drain pan 28 is generally inclined to facilitate drainage to the drain tube 29. However, the defrosting water is formed by forming a water receiver below the opening of the drain tube 29. Keep the water in the refrigerator once. By gradually evaporating this by the evaporating means 27, it is possible to constantly increase the humidity of the refrigerator compartment 2.
[0143]
In the fourth embodiment, the evaporating means 27 is configured to land on the defrost water above the drain pan 28. However, the same applies when the evaporating means 27 is disposed in contact with the lower part of the drain pan 28. This is advantageous in terms of cost because it is not necessary to perform the rust prevention treatment.
[0144]
In the fourth embodiment, the evaporating dish 30 is arranged above the compressor 4. However, a pipe portion formed of at least a part of the first condenser 16 is provided on the evaporating dish 30 so as to be able to exchange heat. Thus, it is possible to arrange an evaporating dish with a high degree of freedom and space efficiency.
[0145]
In the fourth embodiment, the defrost water is discharged to the outside of the heat insulating box 1 by the drain tube 29. However, the defrost water is held in the refrigerator compartment 2 by the drain pan 28 and the evaporating means 27. It is advantageous in terms of cost by employing a configuration in which the drain tube 29 and the evaporating dish 30 are not provided, and the space for the storage section of the compressor 4 can be increased in internal volume or the heat insulation wall can be thickened. It can be used effectively.
[0146]
【The invention's effect】
As described above, the invention according to claim 1 includes a heat-insulating box constituting a refrigerator compartment and a freezer compartment, a first evaporator in the refrigerator compartment, and a second evaporator in the refrigerator compartment. And a refrigerator cooling cycle including a first condenser, a second condenser, and the first evaporator, and the first condenser, the third condenser, and the second evaporator. And a switching means for switching between the respective cooling cycles is provided, wherein the third condenser is disposed in the refrigerator compartment, and when the freezing compartment cooling cycle is operated. Conventionally, the condenser exchanges heat according to the ambient temperature and radiates heat, but the third condenser radiates heat in the refrigerator compartment where the temperature inside the refrigerator is set to about 0 to 5 ° C, so that the condensing temperature can be further reduced. It is. Therefore, the freezing room cooling cycle can be operated at a low compression ratio, and the coefficient of performance is improved.
[0147]
In addition, the load of the refrigerator compartment increases due to the heat radiation load from the condenser, but the cooling efficiency of the refrigerator compartment can be lowered by setting a relatively high evaporation temperature, and the coefficient of performance is lower than that of the freezer compartment. Since it is good, the increase in power consumption is relatively small, the coefficient of performance of the cooling cycle is generally improved, and the power consumption with respect to the load of the refrigerator can be reduced.
[0148]
Further, it is possible to provide a refrigerating refrigerator capable of improving reliability, for example, by lowering the discharge gas temperature of the compressor by reducing the compression ratio.
[0149]
According to a second aspect of the present invention, in addition to the first aspect, the temperature in the freezer compartment can be set to a temperature lower than the normal freezing temperature of −20 ° C. Even when the evaporation temperature is set lower, it can be operated without increasing the compression ratio of the freezing room cooling cycle, the coefficient of performance can be improved, and the power consumption in low-temperature refrigeration can be reduced. It is possible. Further, it is possible to provide a refrigerator-freezer capable of improving the reliability of the compressor at a low evaporation temperature.
[0150]
According to a third aspect of the present invention, in addition to the first or second aspect, the refrigerating room cooling cycle includes a compressor, the first condenser, the second condenser, and a second condenser. One decompression means, the first evaporator, and the first suction pipe are connected in a ring, and the freezing room cooling cycle includes the compressor, the first condenser, the third condenser, and the The second decompression means and the second evaporator and the second suction pipe are connected in a ring, and the second suction pipe and the first condenser are disposed so as to be able to exchange heat, Cooling the refrigerant passing through the capillary to increase the refrigeration effect, raise the temperature of the suction gas of the compressor to the ambient temperature, reduce the heat loss of the suction gas of the compressor, and arrange it outside the heat insulation box. Temperature of the suction pipe Condensation is for both to prevent corrosion.
[0151]
In particular, when the condensing temperature in the freezer compartment cooling cycle is greatly reduced, the heat exchange temperature difference decreases and the amount of heat exchange decreases. It is possible to provide a refrigerator-freezer capable of improving the coefficient and reducing the power consumption.
[0152]
According to a fourth aspect of the present invention, in addition to the first aspect of the present invention, a cycle component from the third condenser to the second evaporator and By burying and insulating the connection pipe in the heat insulating box, since it is not disposed outside the heat insulating box, it is possible to prevent reheating after heat exchange to a low temperature in the refrigerator compartment without lowering the coefficient of performance of the cooling cycle. In addition, it is possible to provide a refrigerating refrigerator which can prevent generation of flash gas and has a reduced power consumption with high reliability.
[0153]
According to a fifth aspect of the present invention, in addition to any one of the first to fourth aspects, at least a part of the second condenser has an opening seal portion of the heat insulating box. It is a means of preventing condensation that is provided in the vicinity, and compared to the case where piping for the freezing room cooling cycle is provided, it is possible to prevent drip without accelerating condensation due to a decrease in condensation temperature, and refrigeration Since the heat intrusion of the heat radiating pipe into the insulated box housing can be suppressed only during the room cooling operation, a refrigerator having a reduced refrigerator load and reduced power consumption can be provided.
[0154]
According to a sixth aspect of the present invention, in addition to any one of the first to fifth aspects, a vacuum heat insulating material is used for the heat insulating wall around the cold room to reduce the load of the cold room. Since the load is smaller than the load, the load of the refrigerator compartment can be reduced without reducing the internal volume or increasing the external shape. Since the load of the refrigerator compartment is smaller than the load of the refrigerator compartment and the load capacity of the refrigerator compartment, the effect of reducing the power consumption by improving the coefficient of performance of the refrigerator compartment cooling cycle is increased, and a refrigerator with even lower power consumption is provided. it can.
[0155]
According to a seventh aspect of the present invention, in addition to the first aspect of the invention, at least a part of the third condenser is provided in the refrigerator compartment. It is arranged so as to be able to exchange heat with the first evaporator, and uses the sensible heat and latent heat of the frost attached to the first evaporator by the operation of the refrigerator cooling cycle to form heat with the third condenser. Since the replacement is performed, a heating unit for defrosting is unnecessary, and the electric power required for the heating can be reduced. Furthermore, since the latent heat of evaporation of frost is much larger than the sensible heat, the amount of heat exchange in the third condenser is also large, and the refrigeration that can further improve the coefficient of performance and reduce power consumption further Refrigerator can be provided.
[0156]
According to an eighth aspect of the present invention, in addition to the seventh aspect, the first evaporator and the third condenser are of a fin coil type, and each fin is shared by a pipe. The fins increase the heat exchange area to cool the inside of the refrigerator compartment and are used for heat exchange of the condenser. In order to increase the area, it is possible to provide a refrigerator-freezer which can further increase the coefficient of performance and can reduce the power consumption at low cost by using the same.
[0157]
According to a ninth aspect of the present invention, in addition to any one of the seventh and eighth aspects of the present invention, the heat storage section of the first evaporator and the third condenser has cold storage. Since the heat is radiated from the condenser by the cooling capacity stored in the cold storage material at the time of cooling the refrigerator compartment, a large capacity can be obtained, and the influence of the temperature fluctuation in the refrigerator compartment can be reduced.
[0158]
According to a tenth aspect of the present invention, in addition to the first aspect of the present invention, the third condenser is smaller than a diameter of a pipe constituting an evaporator. Because the refrigerant is liquefied in the downstream part of the pipe of the third condenser, the amount of the refrigerant required for the cooling cycle is reduced by reducing the volume in the pipe. It becomes possible. In particular, when a flammable refrigerant such as R600a is used, safety design becomes relatively easy.
[0159]
According to an eleventh aspect of the present invention, in addition to any one of the first to tenth aspects, at least a part of the piping of the third condenser has a temperature inside the refrigerator compartment. It is a heating means for compensation and is arranged so that heat can be exchanged in the area where heating is required.It is possible to prevent freezing and dew condensation in the refrigerator by radiating the condenser without using the electric heater in the refrigerator. It is possible to provide an energy-saving refrigerator-freezer capable of reducing the heater input.
[0160]
According to a twelfth aspect of the present invention, in addition to the eleventh aspect of the present invention, an automatic ice maker is provided in the freezing room and a water supply device is provided in the refrigeration room to prevent the water tank of the water supply device from freezing. The heating means is provided in the vicinity of the water tank, and it is possible to prevent the freezing and dew condensation in the refrigerator by radiating heat of the condenser without using the electric heater in the refrigerator. Can be provided.
[0161]
According to a thirteenth aspect of the present invention, in addition to the eleventh aspect of the present invention, a refrigerator compartment duct is provided in the refrigerator compartment warehouse, and the third panel is provided on a rear surface of a duct panel constituting the refrigerator compartment duct. The refrigerator can be prevented from freezing and dew condensation by the heat radiation of the condenser without using the electric heater inside the refrigerator, and a highly reliable refrigerator can be provided while reducing the heater input.
[0162]
According to a fourteenth aspect of the present invention, in addition to any one of the first to eleventh aspects, the drain pan receives defrost water from the first evaporator in the refrigerator compartment. A drain tube for discharging the defrost water to the outside, wherein at least a part of the piping of the third condenser is provided as evaporating means arranged in the vicinity so as to heat the drain pan; It is possible to provide an energy-saving refrigerator-freezer that can promote evaporation of frost and defrost water that has fallen from a vessel to a drain pan and reduce heater power for preventing frost residue and drain freezing.
[0163]
According to a fifteenth aspect of the present invention, in addition to the fourteenth aspect, the drain pan has a receiving structure for temporarily retaining defrost water below an opening of the drain tube, and It is characterized by humidification in the refrigerator, so even if there is little food in the refrigerator, the defrost water is retained in the drain pan and this is heated by the condenser. It is possible to provide a refrigerating refrigerator that can humidify the interior, maintain high humidity in the refrigerator compartment, and improve the freshness of the food in the refrigerator compartment.
[0164]
According to a sixteenth aspect of the present invention, in addition to any one of the first to eleventh aspects, the drain pan and the evaporating means hold defrost water in the refrigerator compartment and evaporate. As a result, a drain tube and an evaporating dish are not provided, so that the number of parts can be reduced and a low-cost refrigerator-freezer can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of a refrigerator-freezer according to a first embodiment of the present invention.
FIG. 2 is a Mollier diagram of a refrigerating room cooling cycle of the refrigerator according to the embodiment.
FIG. 3 is a Mollier diagram of a freezing room cooling cycle of the refrigerator according to the embodiment.
FIG. 4 is a characteristic diagram of compressor efficiency according to the embodiment.
FIG. 5 is a schematic sectional view of a refrigerator-freezer according to a second embodiment of the present invention.
FIG. 6 is a schematic sectional view of a refrigerator-freezer according to a third embodiment of the present invention.
FIG. 7 is a schematic sectional view of a refrigerator-freezer according to a fourth embodiment of the present invention.
FIG. 8 is a schematic sectional view of a conventional refrigerator-freezer.
[Explanation of symbols]
1 Insulated box
2 Cold room
3 Freezer compartment
4 Compressor
6 first capillary
7 First evaporator
8 The second capillary
9 Second evaporator
10 Electric three-way valve
11 Check valve
12 First electric fan
13 Second electric fan
14. Cold room cooling cycle
15 Freezer cooling cycle
16 First condenser
17 Second condenser
19 First suction pipe
20 Third condenser
22 Second suction pipe
23 Refrigerator compartment duct
24 Freezer duct
25 heating means
26 Duct panel
27 Evaporation means
28 drain pan
29 drain tube
30 evaporating dishes

Claims (16)

A heat insulating box constituting a refrigerator compartment and a freezer compartment, a first evaporator in the refrigerator compartment, a second evaporator in the freezer compartment, a first condenser and a second condenser, Refrigerator compartment cooling cycle including the first evaporator, and freezing compartment cooling cycle including the first condenser, the third condenser, and the second evaporator, and each cooling cycle is switched. A refrigerator comprising: a switching unit; and the third condenser is disposed in the refrigerator compartment. 2. The refrigerator according to claim 1, wherein the temperature in the freezer compartment can be set to a temperature lower than -20 [deg.] C. which is a normal freezing temperature. The refrigerating compartment cooling cycle has a compressor, the first condenser, the second condenser, the first decompression means, the first evaporator, and the first suction pipe connected in a ring shape, The freezer compartment cooling cycle has the compressor, the first condenser, the third condenser, the second decompression means, the second evaporator, and the second suction pipe connected in a ring shape, The refrigerator according to claim 1 or 2, wherein a second suction pipe and the first condenser are arranged so as to be able to exchange heat. The cycle component and the connection pipe from the third condenser to the second evaporator are buried in the heat-insulating box to be thermally insulated. 5. Refrigerator-freezer. The refrigeration apparatus according to any one of claims 1 to 4, wherein at least a part of the second condenser is a dew-condensation prevention means disposed near an opening seal portion of the heat-insulating box. refrigerator. The refrigerator according to any one of claims 1 to 5, wherein a load on the refrigerator compartment is made smaller than a load on the refrigerator compartment by using a vacuum heat insulating material for the heat insulation wall around the refrigerator compartment. The at least one part of the said 3rd condenser was arrange | positioned so that heat exchange with the said 1st evaporator in the said refrigerator compartment storage was possible, The Claim 1 characterized by the above-mentioned. A refrigerator as described. The refrigerator according to claim 7, wherein the first evaporator and the third condenser are of a fin coil type, and each of the fins is shared to form a piping path. The refrigerator according to any one of claims 7 to 8, wherein a heat storage material is provided in a heat exchange part of the first evaporator and the third condenser. The refrigerator according to any one of claims 1 to 9, wherein the third condenser is configured using a pipe smaller than a diameter of a pipe forming an evaporator. 2. The apparatus according to claim 1, wherein at least a part of the piping of the third condenser is a heating means for temperature compensation in the refrigerator compartment, and is disposed so as to be capable of exchanging heat at a portion requiring heating. 3. The refrigerator according to claim 10. 12. The refrigerator according to claim 11, wherein an automatic ice maker is provided in the freezer compartment and a water supply device is provided in the refrigerator compartment, and the heating means is provided near the water tank to prevent the water supply device water tank from freezing. Refrigerator-freezer. The refrigerator according to claim 11, wherein a refrigerator compartment duct is provided in the refrigerator compartment, and the third condenser is in contact with a rear surface of a duct panel constituting the refrigerator compartment duct. A drain pan for receiving defrost water from the first evaporator and a drain tube for discharging defrost water to the outside are provided in the refrigerator compartment, and at least a part of piping of the third condenser is connected to the drain pan. The refrigerator according to any one of claims 1 to 11, characterized in that the refrigerator is an evaporating means arranged in the vicinity so as to be heated. 15. The refrigerator according to claim 14, wherein the drain pan has a receiving structure for temporarily retaining defrost water below an opening of the drain tube, and the inside of the refrigerator is humidified by the evaporating means. 12. The structure according to claim 1, wherein the drain pan and the evaporating means hold and evaporate defrost water in the refrigerator compartment and evaporate without providing a drain tube or an evaporating dish. The refrigerator according to claim 1.

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