JP4284789B2

JP4284789B2 - refrigerator

Info

Publication number: JP4284789B2
Application number: JP31056899A
Authority: JP
Inventors: 泰樹浜野; 義人木村; 哲哉斎藤
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 1999-11-01
Filing date: 1999-11-01
Publication date: 2009-06-24
Anticipated expiration: 2019-11-01
Also published as: JP2001133113A

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerator in which energy can be saved and the quantity of refrigerant can be reduced by cooling a refrigeration compartment and a freezing compartment while switching thereby enhancing the efficiency of a cooling system. SOLUTION: In a cooling cycle where a refrigeration compartment 4 and a freezing compartment 6 are cooled independently by switching the flow of refrigerant to a refrigeration compartment side cooling circuit having a first evaporator 3 of relatively high evaporation temperature and a freezing compartment side cooling circuit having a second evaporator 5 of relatively low evaporation temperature through a channel control means 12, the quantity of refrigerant required by the refrigeration compartment side cooling circuit for cooling the refrigeration compartment 4 is set smaller as compared with the quantity of refrigerant required by the freezing compartment side cooling circuit for cooling the freezing compartment 6.

Description

【０００１】
【発明の属する技術分野】
本発明は、冷凍室と冷蔵室とを互いに独立に冷却を行う冷却システムの高効率化と冷媒量削減および安全性向上に関するものである。
【０００２】
【従来の技術】
図１６に従来の冷却サイクル並びに冷蔵庫の一例として、特公昭６２−２２３９６号公報に開示されている冷蔵庫の冷却サイクル図を示す。
【０００３】
１は圧縮機、２は凝縮器、３は冷蔵室４内に配設された第一の蒸発器であり、５は冷凍室６内に配設された第二の蒸発器である。
【０００４】
７は冷蔵室冷却用である第一の蒸発器３の冷媒回路上流側に配設された第一のキャピラリであり、８は冷凍室冷却用である第二の蒸発器５の冷媒回路上流側に配設された第二のキャピラリであり、９は冷凍室冷却用の第二の蒸発器５の下流側に設けた逆止弁である。
【０００５】
１０は第一の蒸発器３の冷媒回路下流側に配設された第一の開閉弁であり、１１は第二のキャピラリ８の冷媒回路上流側に設けられた第二の開閉弁である。
【０００６】
以上のように構成された従来例の冷蔵庫について、以下その動作を説明する。
【０００７】
冷凍サイクルの運転は以下のように行われる。まず圧縮機１により圧縮された冷媒が凝縮器２で凝縮液化される。凝縮された冷媒は第一のキャピラリ７もしくは第二のキャピラリ８で減圧されて、それぞれ第一の蒸発器３、第二の蒸発器５へ流入，蒸発気化された後、再び圧縮機１へと吸入される。
【０００８】
冷媒が蒸発気化することにより比較的低温となった第一の蒸発器３、第二の蒸発器５と冷蔵室４，冷凍室６の空気が熱交換することにより各室が冷却される。
【０００９】
冷蔵庫の冷却運転は図示しない各室の温度検知手段と制御手段により以下のように行われる。
【００１０】
冷蔵室４，冷凍室６の各温度検知手段が所定値以上の温度手段を検知すると圧縮機１が起動し、冷凍サイクルの運転が行われる。冷蔵室４の温度検知手段が所定値以下となるまで第一の開閉弁１０が開放となり、第二の開閉弁１１は閉止となる。
【００１１】
これにより冷媒は第二の蒸発器５には流入することなく、第一の蒸発器３へのみ流れる。このときの冷凍サイクルの蒸発温度の設定は、冷蔵室４の温度設定が５℃程度に対して−５〜０℃であり、通常の−３０〜−２５℃の蒸発温度に対して２〜２．５倍の成績係数で圧縮機の運転が可能である。
【００１２】
冷蔵室４が冷却されて温度が低下し、温度検知手段が所定値以下を検知すると、第一の開閉弁１０が閉止し、第二の開閉弁１１が開放となる。
【００１３】
これにより冷媒は第二の蒸発器５へと流入し、冷凍室６の冷却が行われる。このときの冷凍サイクルの蒸発温度は冷凍室の温度設定が−１８℃程度に対し通常の蒸発温度（−３０〜−２５℃）で冷却される。
【００１４】
以上のように冷蔵室４と冷凍室６とを蒸発器への冷媒供給時間を分配して、交互に繰り返し冷却するので、冷蔵室４冷却時は独立的に冷媒を第一の蒸発器へと循環させることで低圧圧力調整弁が不要で高蒸発温度（−５〜０℃）が可能であり、圧縮機１の圧縮比を小さくでき、高い成績係数で運転を行い効率化を図るものである。
【００１５】
さらに、逆止弁９は冷蔵室４冷却中の蒸発温度が高いので、第二の蒸発器５に冷媒が流れ込むのを防止するものである。
【００１６】
また、冷凍室６の冷却を行う場合、冷蔵室４の冷却中に比較して冷媒量が少なくてすむので、通常は冷媒量過多となる。しかしながら第一の開閉弁１０が第一の蒸発器３の下流側に設けてあり、これを閉止するので第一の蒸発器３に冷媒を溜め込むことが可能であり、冷媒量調節ができる。
【００１７】
【発明が解決しようとする課題】
上記従来の冷蔵庫にあっては、冷蔵室４と冷凍室６とを蒸発器への冷媒供給時間を分配して、交互に繰り返し冷却することで冷蔵室４冷却時の冷凍サイクルを圧縮機１の成績係数がよい比較的高蒸発温度（−５〜０℃）で運転することを可能としている。
【００１８】
しかし、冷凍室６内に配設された第二の蒸発器５の蒸発温度（−３０〜−２５℃）は、冷蔵室４内に配設された第一の蒸発器３の蒸発温度（−５〜０℃）と比較してかなり低い温度であり圧力も低い状態となっている。
【００１９】
また、冷蔵室４の冷却中は冷蔵室４内に配設された第一の蒸発器３の温度は−５〜０℃であるが、冷凍室６内の温度は例えば約−１８℃と低いために冷凍室６内に配設された第二の蒸発器５の温度も約−１８℃程度であり、第一の蒸発器３の温度と比較して第二の蒸発器５の温度がかなり低いため、圧力も低い状態となっているので、第二の蒸発器５に滞留した冷媒は第二の蒸発器５から流出しにくい。その結果、第一の蒸発器３に充分な冷媒が供給されず、冷媒循環量不足となり冷蔵室４の冷却効率が低下することとなる。
【００２０】
特に、冷蔵室４の冷却を行う場合の必要冷媒量が冷凍室６の冷却を行う場合の必要冷媒量と比較して多い場合は、冷蔵室４の冷却時において、冷凍室６内に配設された低温，低圧の第二の蒸発器５に滞留した冷媒を第一の蒸発器３から全て回収しなければならないため、第一の蒸発器３に充分な冷媒が供給されず、冷媒循環量不足となり冷蔵室４の冷却効率が低下する傾向は強くなる。
【００２１】
また、上記した冷蔵室４の冷却時の冷媒循環量不足による冷却効率低下を防止する施策として、第一の蒸発器３の出口側または第二の蒸発器５の出口側に冷媒貯留手段を設け、必要以上に冷媒を封入する方法が考えられるが、この方法では冷却サイクル内に存在する冷媒量が増大するため、可燃性自然冷媒を用いる場合には冷媒漏洩時の危険性が高く問題がある。
【００２２】
本発明は、以上のような従来の課題を解決するもので、冷蔵室と冷凍室の冷却を切り替えて行う冷却システムの効率向上を行うことで、省エネルギーが可能である冷蔵庫を提供することを目的とする。
【００２３】
また、上記の結果より冷媒を効率よく利用することができるので冷媒量を削減でき、特に可燃性自然冷媒（イソブタン，プロパン等）を用いる場合には、その冷媒量削減により、冷媒漏洩時の安全性を高めることが可能な冷蔵庫を提供することを目的とする。
【００２４】
【課題を解決するための手段】
この目的を達成するために本発明の冷蔵庫は、圧縮機と、凝縮器と、流路制御手段と、第一の減圧手段と、冷蔵室内に配設された第一の蒸発器と、第一の送風手段と、第二の減圧手段と、冷凍室内に配設された第二の蒸発器と、第二の送風手段と、逆止弁とを備え、前記圧縮機と前記凝縮器と前記流路制御手段と前記第一の減圧手段と前記第一の蒸発器とで冷蔵室側冷却回路を形成するとともに、前記第一の減圧手段と前記第一の蒸発器に並列となるように前記第二の減圧手段と前記第二の蒸発器と前記逆止弁とを接続し、前記圧縮機と前記凝縮器と前記流路制御手段と前記第二の減圧手段と前記第二の蒸発器と前記逆止弁とで冷凍室側冷却回路を形成し、前記流路制御手段により各冷却回路への冷媒の流れを切り替えることで前記冷蔵室と前記冷凍室の冷却を互いに独立して行うものであり、第一の蒸発器を構成する配管内の容量が第二の蒸発器を構成する配管内の容量と比較して小容量とすることで、前記冷蔵室を冷却するための前記冷蔵室冷却回路の必要冷媒量が前記冷凍室を冷却するための前記冷凍室側冷却回路の必要冷媒量と比較して少なくし、圧縮機は能力可変型であり、冷蔵室の冷却を開始する際に、所定時間のあいだ圧縮機を通常の回転数より高い回転数で運転することで、前記冷凍室の冷却から前記冷蔵室の冷却へ切り換わった時に、第二の蒸発器に滞留した冷媒の一部を第一の蒸発器に循環させて、前記冷蔵室を冷却するための必要冷媒量を確保したことを特徴とする。
【００２６】
また、第一の減圧手段による減圧量が０．２ＭＰａ以上０．５ＭＰａ以下であることを特徴とする。
【００２８】
また、第二の蒸発器の除霜を定期的に行う除霜ヒータを備え、冷蔵室の冷却を開始する際に、所定時間のあいだ除霜ヒータに通電することを特徴とする。
【００２９】
また、第二の蒸発器の除霜を定期的に行う除霜ヒータを備え、冷蔵室の冷却を開始する際に、所定時間のあいだ除霜ヒータに断続的に通電することを特徴とする。
【００３０】
さらに、冷蔵室の冷却を開始する際に、所定時間のあいだ第二の送風手段を運転することを特徴とする。
【００３１】
また、圧縮機は低圧容器型であり、冷却サイクルの冷媒に可燃性自然冷媒（イソブタン，プロパン等）を用いたことを特徴とする。
【００３２】
この本発明によれば、冷蔵室と冷凍室の冷却を切り替えて行う冷却システムの冷媒量削減と効率向上を行うことで、省エネルギーが可能である冷蔵庫を提供することができる。
【００３３】
また、上記の結果より冷媒を効率よく利用することができるので冷媒量を削減でき、特に可燃性自然冷媒（イソブタン，プロパン等）を用いる場合には、その冷媒量削減により、冷媒漏洩時の安全性を高めることが可能な冷蔵庫を提供することができる。
【００３４】
【発明の実施の形態】
本発明の請求項１に記載の発明は、圧縮機と、凝縮器と、流路制御手段と、第一の減圧手段と、冷蔵室内に配設された第一の蒸発器と、第一の送風手段と、第二の減圧手段と、冷凍室内に配設された第二の蒸発器と、第二の送風手段と、逆止弁とを備え、前記圧縮機と前記凝縮器と前記流路制御手段と前記第一の減圧手段と前記第一の蒸発器とで冷蔵室側冷却回路を形成するとともに、前記第一の減圧手段と前記第一の蒸発器に並列となるように前記第二の減圧手段と前記第二の蒸発器と前記逆止弁とを接続し、前記圧縮機と前記凝縮器と前記流路制御手段と前記第二の減圧手段と前記第二の蒸発器と前記逆止弁とで冷凍室側冷却回路を形成し、前記流路制御手段により各冷却回路への冷媒の流れを切り替えることで前記冷蔵室と前記冷凍室の冷却を互いに独立して行うものであり、第一の蒸発器を構成する配管内の容量が第二の蒸発器を構成する配管内の容量と比較して小容量とすることで、前記冷蔵室を冷却するための前記冷蔵室冷却回路の必要冷媒量が前記冷凍室を冷却するための前記冷凍室側冷却回路の必要冷媒量と比較して少なくし、圧縮機は能力可変型であり、冷蔵室の冷却を開始する際に、所定時間のあいだ圧縮機を通常の回転数より高い回転数で運転することで、前記冷凍室の冷却から前記冷蔵室の冷却へ切り換わった時に、第二の蒸発器に滞留した冷媒の一部を第一の蒸発器に循環させて、前記冷蔵室を冷却するための必要冷媒量を確保したことを特徴とする。
【００３５】
以上の構成により、冷蔵室を冷却するための必要冷媒量が冷凍室を冷却するための必要冷媒量と比較して少ないことにより、冷蔵室の冷却を行う際に、低温，低圧の第二の蒸発器に滞留した冷媒の一部が第一の蒸発器に循環すれば、冷蔵室を冷却するための必要冷媒量を確保できるため、第一の蒸発器の循環量不足を解消し、冷蔵室の冷却効率を向上することで省エネルギー化が可能となる。
【００３６】
また、上記の結果より冷媒を効率よく利用することができるので冷媒量を削減でき、特に可燃性自然冷媒（イソブタン，プロパン等）を用いる場合には、その冷媒量削減により、冷媒漏洩時の安全性を高めることが可能となる。
冷却システムにおいて蒸発器を構成する配管内の容量が小さいほど、必要冷媒量が減少する傾向があるため、第一の蒸発器を構成する配管内の容量が第二の蒸発器を構成する配管内の容量と比較して小容量である場合には、冷蔵室を冷却するための必要冷媒量が冷凍室を冷却するための必要冷媒量と比較して少ない傾向となり、冷蔵室の冷却を行う際に、低温，低圧の第二の蒸発器に滞留した冷媒の一部が第二の蒸発器に循環すれば、冷蔵室を冷却するための必要冷媒量を確保できるため、第一の蒸発器の循環量不足を解消し、冷蔵室の冷却効率を向上することで省エネルギー化が可能となる。
冷蔵室の冷却を開始する際に、所定時間のあいだ圧縮機を通常の回転数より高い回転数で運転することにより、低温，低圧の第二の蒸発器に滞留した冷媒の回収能力を高めるとともに、冷媒を強い力で多量に第一の蒸発器に押し出すことができるため、冷媒循環量不足にならず、冷蔵室の冷却効率向上が可能となる。
【００３９】
請求項２に記載の発明は、第一の減圧手段による減圧量が０．２ＭＰａ以上０．５ＭＰａ以下であることを特徴とする。
【００４０】
第一の減圧手段による減圧量を通常の減圧量（０．６ＭＰａ程度）より小さい０．２ＭＰａ以上０．５ＭＰａ以下とすることで冷媒が第一の減圧手段を通過する際の抵抗が小さく、冷媒が流れ易くなり、冷蔵室の冷却を開始した際、冷媒が抵抗の小さい第一の減圧手段を介して第一の蒸発器に速やかに移動するため冷媒循環量不足にならず、冷蔵室の冷却効率向上が可能となる。
【００４３】
請求項３に記載の発明は、第二の蒸発器の除霜を定期的に行う除霜ヒータを設け、冷蔵室の冷却を開始する際に、所定時間のあいだ除霜ヒータに通電することを特徴とする。
【００４４】
冷蔵室の冷却を行う際に、所定時間のあいだ除霜ヒータに通電することにより、冷蔵室の冷却中に第二の蒸発器の温度及び圧力の上昇を促進できるため、第二の蒸発器に滞留した冷媒を回収する効率を向上させることができ、第一の蒸発器の冷媒循環量不足の時間を短縮し、冷蔵室の冷却効率向上が可能となる。
【００４５】
請求項４に記載の発明は、第二の蒸発器の除霜を定期的に行う除霜ヒータを設け、冷蔵室の冷却を開始する際に、所定時間のあいだ除霜ヒータに断続的に通電することを特徴とする。
【００４６】
冷蔵室の冷却を行う際に、除霜ヒータに通電することにより、冷蔵室の冷却中に第二の蒸発器の温度及び圧力の上昇を促進できるため、第二の蒸発器に滞留した冷媒を回収する効率を向上させることができ、第一の蒸発器の冷媒循環量不足の時間を短縮することができるが、例えば冷凍室内及び冷蔵室内の温度差が小さい場合のように、負荷状態によってはポンプダウン後の冷蔵室の冷却時に所定時間のあいだ連続して通電しなくても、冷媒循環量不足の時間が充分に短い場合がある。このような場合には、ポンプダウン後の冷蔵室の冷却時の除霜ヒータの通電を、例えばデューティ制御等により断続的に行うことにより、除霜ヒータによる消費電力を低減することが可能となる。
【００４７】
請求項５に記載の発明は、冷蔵室の冷却を開始する際に、所定時間のあいだ第二の送風手段を運転することを特徴とする。
【００４８】
冷蔵室の冷却を行う際に、所定時間のあいだ第二の送風手段を運転することにより、冷蔵室の冷却中に第二の蒸発器の温度及び圧力の上昇を促進できるため、第二の蒸発器に滞留した冷媒を回収する効率を向上させることができ、第一の蒸発器の冷媒循環量不足の時間を短縮し、冷蔵室の冷却効率向上が可能な冷蔵庫を提供できる。
【００４９】
請求項６に記載の発明は、圧縮機は低圧容器型であり、冷却サイクルの冷媒に可燃性自然冷媒（イソブタン，プロパン等）を用いたことを特徴とする。
【００５０】
上記の結果より、冷凍室の冷却から冷蔵室の冷却に切り替わる際の第一の蒸発器の冷媒循環量不足を解消または緩和することにより、冷媒を効率よく利用できるので冷媒量を削減でき、特に可燃性自然冷媒（イソブタン，プロパン等）を用いる場合には、その冷媒量削減により、冷媒漏洩時の安全性を高めることが可能となる。
【００５１】
以下、本発明の実施の形態について図１から図１５を用いて説明する。従来例と同一構成についてはその詳細な説明を省略し、同一符号を付す。
【００５２】
（実施の形態１）
図１は本発明の一実施の形態による冷蔵庫の冷却サイクル図、図２は同実施の形態による流路制御手段の概略断面図、図３は同実施の形態による第一の蒸発器の冷媒封入量特性図、図４は同実施の形態による第二の蒸発器の冷媒封入量特性図、図５は同実施の形態による冷蔵庫の運転タイムチャートである。
【００５３】
圧縮機１と、凝縮器２と、流路制御手段１２と、第一の減圧手段７と、冷蔵室４内に配設された第一の蒸発器３と、第一の送風手段１３と、第二の減圧手段８と、冷凍室６内に配設された第二の蒸発器５と、第二の送風手段１４と、逆止弁９とを備え、圧縮機１と凝縮器２と第一の減圧手段７と第一の蒸発器３とで冷蔵室側冷却回路を形成するとともに、第一の減圧手段７と第一の蒸発器３に並列となるように第二の減圧手段８と第二の蒸発器５と逆止弁９とを接続し、圧縮機１と凝縮器２と第二の減圧手段８と第二の蒸発器５と逆止弁９とで冷凍室側冷却回路を形成している。
【００５４】
１５は冷蔵庫箱体であり、上方部に比較的高温の区画である冷蔵室４を、下方部に比較的低温の区画である冷凍室６を配置してあり、例えばウレタンのような断熱材で周囲と断熱して構成している。食品等の収納物の出し入れは図示しない断熱ドアを介して行われる。
【００５５】
圧縮機１と凝縮器２と流路制御手段１２は可燃性自然冷媒を使用した場合に安全性向上の面から冷蔵庫箱体１５内での配管接続箇所削減のために機械室１６に配設されている。
【００５６】
冷蔵室４と冷凍室６には区画内温度を検出する図示しない温度検出手段をそれぞれ設けてあり、圧縮機１と流路制御手段１２と第一の送風手段１３と第二の送風手段１４を制御する図示しない制御手段とを備えている。
【００５７】
図２に示すように、流路制御手段１２は三方弁であり、凝縮器２から第二の減圧手段８への冷媒の流れを遮断し、第一の減圧手段７への冷媒の流れを開放（第一の状態）し、冷蔵室側冷却回路を形成する第一の位置１７と、凝縮器２から第一の減圧手段７への冷媒の流れを遮断し、第二の減圧手段８への冷媒の流れを開放（第二の状態）し、冷凍室側冷却回路を形成する第二の位置１８と、凝縮器２の出口側を閉止することにより第一の減圧手段７と第二の減圧手段８への冷媒の流れをともに遮断し、冷却サイクルの高圧側と低圧側を遮断（第三の状態）する第三の位置１９とを備えている。回転軸２０に偏芯して固定されたシール部材２１がシリンダ２２内を回転移動し、第一，第二，第三の位置にそれぞれ停止することで各位置に接続された配管を閉止するものである。回転は図示しない駆動手段と伝達手段により行われる。各位置への位置決めは、例えばパルスモーターの駆動パルス数により制御される。
【００５８】
冷蔵室４を冷却するための冷蔵室側冷却回路の必要冷媒量について図３を用いて説明する。
【００５９】
図３は、例えば外気温度が３０℃程度において、流路制御手段１２を第一の状態とし、冷蔵室４を冷却するための冷蔵室側冷却回路を形成し、圧縮機１及び第一の送風手段１３を連続して運転させた状態で、冷蔵室側冷却回路に封入する冷媒量（冷媒封入量）を変化させた場合の安定時における第一の蒸発器３の冷媒入口温度，冷媒出口温度、及び冷蔵室４の庫内温度の関係を表す。
【００６０】
冷媒封入量が４０ｇの場合は、第一の蒸発器３の冷媒出口温度が冷媒入口温度と比較して高く、冷媒循環量が不足している状態であり、冷蔵室４の冷却効率が悪く、冷蔵室４の庫内温度も高い状態となっている。
【００６１】
冷媒封入量が５０ｇにおいて、第一の蒸発器３の冷媒入口温度と冷媒出口温度は同等の温度となり、冷媒循環量が過不足のない状態であり、冷蔵室４の冷却効率が良く、冷蔵室４の庫内温度も低い状態となっている。
【００６２】
一般的には、圧縮機１の起動時等の過渡運転状態における圧縮機１への液バック現象を防止するために、第一の蒸発器３の冷媒出口側には冷媒貯留手段が設けられる。冷媒封入量が６０ｇ〜８０ｇのあいだは、冷媒封入量としては過封入の状態であるが、この冷媒貯留手段による貯留効果（余裕度）により、第一の蒸発器３の冷媒入口温度と冷媒出口温度は同等の温度を保ち、冷蔵室４の冷却効率が良く、冷蔵室４の庫内温度も低い状態を保つ。冷媒封入量が９０ｇをこえると、冷媒貯留手段による貯留効果（余裕度）以上の冷媒が存在することになり、圧縮機１に液冷媒が吸入されるという液バック現象を起こし、第一の蒸発器３の蒸発温度は上昇し、冷蔵室４の冷却効率も悪化する。
【００６３】
冷蔵室４を冷却するための冷蔵室側冷却回路の冷媒循環量が過不足のない状態における冷媒封入量（この場合は５０ｇ）を冷蔵室４を冷却するための必要冷媒量とする。
【００６４】
図４は、例えば外気温度が３０℃程度において、流路制御手段１２を第二の状態とし、冷凍室６を冷却するための冷凍室側冷却回路を形成し、圧縮機１及び第二の送風手段１４を連続して運転させた状態で、冷凍室側冷却回路に封入する冷媒量（冷媒封入量）を変化させた場合の安定時における第二の蒸発器５の冷媒入口温度，冷媒出口温度、及び冷凍室６の庫内温度の関係を表す。
【００６５】
冷媒封入量が７０ｇの場合は、第二の蒸発器５の冷媒出口温度が冷媒入口温度と比較して高く、冷媒循環量が不足している状態であり、冷凍室５の冷却効率が悪く、冷凍室５の庫内温度も高い状態となっている。
【００６６】
冷媒封入量が８０ｇにおいて、第二の蒸発器５の冷媒入口温度と冷媒出口温度は同等の温度となり、冷媒循環量が過不足のない状態であり、冷凍室６の冷却効率が良く、冷凍室６の庫内温度も低い状態となっている。
【００６７】
一般的には、圧縮機１の起動時等の過渡運転状態における圧縮機１への液バック現象を防止するために、第二の蒸発器５の冷媒出口側には冷媒貯留手段が設けられる。冷媒封入量が９０ｇ〜１１０ｇのあいだは、冷媒封入量としては過封入の状態であるが、この冷媒貯留手段による貯留効果（余裕度）により、第二の蒸発器５の冷媒入口温度と冷媒出口温度は同等の温度を保ち、冷凍室６の冷却効率が良く、冷凍室６の庫内温度も低い状態を保つ。冷媒封入量が１２０ｇをこえると、冷媒貯留手段による貯留効果（余裕度）以上の冷媒が存在することになり、圧縮機１に液冷媒が吸入されるという液バック現象を起こし、第二の蒸発器５の蒸発温度は上昇し、冷凍室６の冷却効率も悪化する。
【００６８】
冷凍室６を冷却するための冷凍室側冷却回路の冷媒循環量が過不足のない状態における冷媒封入量（この場合は８０ｇ）を冷凍室６を冷却するための必要冷媒量とする。
【００６９】
上記したように、冷蔵室４を冷却するための必要冷媒量（この例では５０ｇ）が冷凍室６を冷却するための必要冷媒量（この例では８０ｇ）と比較して少ないことを特徴とする。
【００７０】
以上のように構成された冷蔵庫について、冷蔵室４と冷凍室６の冷却のタイミングについて図５のタイムチャートを元に説明する。
【００７１】
冷凍室６の冷却中は、流路制御手段１２は第二の状態であり、第二の蒸発器５へと冷媒が流れ、第二の送風手段１４は運転している。
【００７２】
圧縮機１の運転により吐出された高温高圧の冷媒は、凝縮器２により凝縮液化し、流路制御手段１２を経て第二の減圧手段８で減圧された後、第二の蒸発器５へと流入し、第二の送風手段１４の運転により、冷凍室６内の空気と熱交換することで、第二の蒸発器５内の冷媒は蒸発気化し、熱交換された空気は、より低温の空気となり冷凍室６の冷却を行う。
【００７３】
冷凍室６の冷却中に冷蔵室４の温度検知手段が予め設定された所定の温度を越えていることを検知すると、流路制御手段１２は第一の状態となり、第一の蒸発器３に冷媒が流れ、第一の送風手段１３を運転し、第二の送風手段１４を停止する（Ｔ０１）。
【００７４】
冷媒は、圧縮機１，凝縮器２，流路制御手段１２を経て第一の減圧手段７で減圧された後、第一の蒸発器３へと流入し、第一の送風手段１３の運転により、冷蔵室４内の空気と熱交換することで、第一の蒸発器３内の冷媒は蒸発気化し、熱交換された空気は、より低温の空気となり冷蔵室４の冷却を行う。
【００７５】
冷蔵室４の冷却中に冷凍室６の温度検知手段が予め設定された所定の温度を越えていることを検知すると、流路制御手段１２は第二の状態となり第二の蒸発器５に冷媒が流れ、第一の送風手段１３を停止し、第二の送風手段１４を運転し、冷凍室６の冷却を開始する（Ｔ０２）。
【００７６】
冷媒は、圧縮機１，凝縮器２，第二の開閉弁１１を経て第二の減圧手段８で減圧された後、第二の蒸発器５へと流入し、第二の送風ファン１４の運転により、冷凍室６内の空気と熱交換することで、第二の蒸発器５内の冷媒は蒸発気化し、熱交換された空気は、より低温の空気となり冷凍室６の冷却を行う。
【００７７】
以上の動作を繰り返し、流路制御手段１２により冷媒の流れを切り替えることで冷蔵室４と冷凍室６を交互に冷却し、冷蔵室４と冷凍室６の温度検知手段が予め設定された所定の温度より低いことを検知すると、流路制御手段は第三の状態となり、第一の送風手段１３と第二の送風手段１４をともに停止し、圧縮機１を停止する（Ｔ０３）。
【００７８】
以上述べたように、冷蔵室４の冷却を行う際に、低温，低圧の第二の蒸発器５に滞留した冷媒の一部が第一の蒸発器３に循環すれば、冷蔵室を冷却するための必要冷媒量を確保できるため、第一の蒸発器３の循環量不足を解消し、冷蔵室４の冷却効率を向上することで省エネルギー化が可能となる。
【００７９】
また、上記の結果より冷媒を効率よく利用することができるので冷媒量を削減でき、特に可燃性自然冷媒（イソブタン，プロパン等）を用いる場合には、その冷媒量削減により、冷媒漏洩時の安全性を高めることが可能となる。
【００８０】
なお、流路制御手段１２は三方弁としたが、第一の減圧手段７，第二の減圧手段８の入口側にそれぞれ二方弁を設置しても同等の効果が得られる。
【００８１】
（実施の形態２）
図６（ａ）は他の実施の形態による第一の蒸発器の正面図、図６（ｂ）は同実施の形態による第二の蒸発器の正面図である。
【００８２】
図６に示すように、第一の蒸発器３を構成する配管の長さをＬ１、内径をＤ１、内容量をＶ１とし、第二の蒸発器５を構成する配管の長さをＬ２、内径をＤ２、内容量をＶ２とすると、第一の蒸発器３，第二の蒸発器５を構成する配管の内容量はそれぞれＶ１＝１／４πＤ１²Ｌ１，Ｖ２＝１／４πＤ２²Ｌ２であらわされ、第一の蒸発器３の配管の内容量Ｖ１と第二の蒸発器５の配管の内容量Ｖ２はＶ１＜Ｖ２となるように構成されている。
【００８３】
冷却システムにおいて蒸発器を構成する配管内の容量が小さいほど、必要冷媒量が減少する傾向があるため、第一の蒸発器３を構成する配管内の容量が第二の蒸発器５を構成する配管内の容量と比較して小容量である場合には、冷蔵室４を冷却するための必要冷媒量が冷凍室６を冷却するための必要冷媒量と比較して少ない傾向となり、冷蔵室４の冷却を行う際に、低温，低圧の第二の蒸発器５に滞留した冷媒の一部を回収すれば、冷蔵室４を冷却するのに必要な冷媒量を確保できるため、凝縮器２の出口側流路を、流路制御手段１２により閉鎖した状態で圧縮機１を運転するポンプダウンによる冷媒回収効率を向上することができ、冷蔵室４の冷却効率を向上することで省エネルギー化が可能となる。
【００８４】
また、上記の結果より冷媒を効率よく利用することができるので冷媒量を削減でき、特に可燃性自然冷媒（イソブタン，プロパン等）を用いる場合には、その冷媒量削減により、冷媒漏洩時の安全性を高めることが可能となる。
【００８５】
（実施の形態３）
図７は本発明の他の実施の形態による冷蔵庫の冷却サイクル図、図８は同実施の形態による冷蔵庫の運転タイムチャートである。
【００８６】
図７に示すように、第一の減圧手段７による減圧量Ｒ１は０．２ＭＰａ〜０．５ＭＰａ、通常の減圧量である第二の減圧手段８による減圧量Ｒ２は０．６ＭＰａ程度でありＲ１＜Ｒ２という構成になっている。
【００８７】
冷蔵室４と冷凍室６の冷却のタイミングについて図８のタイムチャートを元に説明する。
【００８８】
冷凍室６の冷却中に冷蔵室４の温度検知手段が予め設定された所定の温度を越えていることを検知すると、流路制御手段１２は第一の状態となり、第一の蒸発器３に冷媒が流れ、第一の送風手段１３を運転し、第二の送風手段１４を停止し、冷蔵室４の冷却を開始する（Ｔ１１）。
【００８９】
冷蔵室４の冷却中に冷凍室６の温度検知手段が予め設定された所定の温度を越えていることを検知すると、流路制御手段１２は第二の状態となり第二の蒸発器５に冷媒が流れ、第一の送風手段１３を停止し、第二の送風手段１４を運転し、冷凍室６の冷却を開始する（Ｔ１２）。
【００９０】
以上の動作を繰り返し、流路制御手段１２により冷媒の流れを切り替えることで冷蔵室４と冷凍室６を交互に冷却し、冷蔵室４と冷凍室６の温度検知手段が予め設定された所定の温度より低いことを検知すると、流路制御手段は第三の状態となり、第一の送風手段１３と第二の送風手段１４をともに停止し、圧縮機１を停止する（Ｔ１３）。
【００９１】
第一の減圧手段７による減圧量を第二の減圧手段８のような通常の減圧量（０．６ＭＰａ程度）より小さい０．２ＭＰａ〜０．５ＭＰａとすることで冷媒が第一の減圧手段７を通過する際の抵抗が小さく、冷媒が流れ易くなり、冷蔵室４の冷却を行う際に、冷媒が抵抗の小さい第一の減圧手段７を介して第一の蒸発器３に速やかに移動するため冷媒循環量不足にならず、冷蔵室４の冷却効率を向上することで省エネルギー化が可能となる。
【００９２】
また、冷媒を効率よく利用することができるので冷媒量を削減でき、特に可燃性自然冷媒（イソブタン，プロパン等）を用いる場合には、その冷媒量削減により、冷媒漏洩時の安全性を高めることが可能となる。
【００９３】
尚、ここでいう減圧手段の減圧量は、減圧手段の入口に窒素ガスにより１．２ＭＰａ（１２ｋｇｆ／ｃｍ²Ｇ）の圧力をかけた場合における減圧手段の入口と出口の圧力差（差圧）とする。
【００９４】
また、減圧量が０．２ＭＰａ〜０．５ＭＰａの状態では、減圧手段による窒素ガスの流量は１２Ｌ／ｍｉｎ〜３０Ｌ／ｍｉｎである。
【００９５】
（実施の形態４）
図９は本発明の他の実施の形態による冷蔵庫の冷却サイクル図、図１０は同実施の形態による冷蔵庫の運転タイムチャートである。
【００９６】
２３は能力可変型の圧縮機である。
【００９７】
冷蔵室４と冷凍室６の冷却のタイミングについて図１０のタイムチャートを元に説明する。
【００９８】
冷凍室６の冷却中に冷蔵室４の温度検知手段が予め設定された所定の温度を越えていることを検知すると、流路制御手段１２は第一の状態となり、第一の蒸発器３に冷媒が流れ、第一の送風手段１３を運転し、第二の送風手段１４を停止し、冷蔵室４の冷却を開始する（Ｔ２１）。
【００９９】
冷蔵室の冷却を開始すると同時に、圧縮機１は通常の回転数より高い回転数で所定の時間（Ｔｂ０）のあいだ運転する。
【０１００】
冷蔵室４の冷却中に冷凍室６の温度検知手段が予め設定された所定の温度を越えていることを検知すると、流路制御手段１２は第二の状態となり第二の蒸発器５に冷媒が流れ、第一の送風手段１３を停止し、第二の送風手段１４を運転し、冷凍室６の冷却を開始する（Ｔ２２）。
【０１０１】
以上の動作を繰り返し、流路制御手段１２により冷媒の流れを切り替えることで冷蔵室４と冷凍室６を交互に冷却し、冷蔵室４と冷凍室６の温度検知手段が予め設定された所定の温度より低いことを検知すると、流路制御手段は第三の状態となり、第一の送風手段１３と第二の送風手段１４をともに停止し、圧縮機１を停止する（Ｔ２３）。
【０１０２】
冷蔵室４の冷却を行う際に、所定時間のあいだ圧縮機１を通常の回転数より高い回転数で運転することにより、冷媒を強い力で多量に第一の蒸発器３に押し出すことができるため、冷媒循環量不足にならず、冷蔵室４の冷却効率を向上することで省エネルギー化が可能となる。
【０１０３】
また、冷媒を効率よく利用することができるので冷媒量を削減でき、特に可燃性自然冷媒（イソブタン，プロパン等）を用いる場合には、その冷媒量削減により、冷媒漏洩時の安全性を高めることが可能となる。
【０１０４】
（実施の形態５）
図１１は本発明の他の実施の形態による冷蔵庫の冷却サイクル図、図１２は同実施の形態による冷蔵庫の運転タイムチャートである。
【０１０５】
２４は第二の蒸発器５の除霜を定期的に行う除霜ヒータである。
【０１０６】
冷蔵室４と冷凍室６の冷却のタイミングについて図１２のタイムチャートを元に説明する。
【０１０７】
冷凍室６の冷却中に冷蔵室４の温度検知手段が予め設定された所定の温度を越えていることを検知すると、流路制御手段１２は第一の状態となり、第一の蒸発器３に冷媒が流れ、第一の送風手段１３を運転し、第二の送風手段１４を停止し、冷蔵室４の冷却を開始する（Ｔ３１）。
【０１０８】
冷蔵室の冷却を開始すると同時に、除霜ヒータ２４を所定の時間（Ｔｂ１）のあいだ通電する。
【０１０９】
冷蔵室４の冷却中に冷凍室６の温度検知手段が予め設定された所定の温度を越えていることを検知すると、流路制御手段１２は第二の状態となり第二の蒸発器５に冷媒が流れ、第一の送風手段１３を停止し、第二の送風手段１４を運転し、冷凍室６の冷却を開始する（Ｔ３２）。
【０１１０】
以上の動作を繰り返し、流路制御手段１２により冷媒の流れを切り替えることで冷蔵室４と冷凍室６を交互に冷却し、冷蔵室４と冷凍室６の温度検知手段が予め設定された所定の温度より低いことを検知すると、流路制御手段は第三の状態となり、第一の送風手段１３と第二の送風手段１４をともに停止し、圧縮機１を停止する（Ｔ３３）。
【０１１１】
冷蔵室４の冷却を行う際、所定時間のあいだ除霜ヒータ２４に通電することにより、冷蔵室４の冷却中に第二の蒸発器５の温度及び圧力の上昇を促進できるため、第二の蒸発器５に滞留した冷媒を回収する効率を向上させることができ、第一の蒸発器３の冷媒循環量不足の時間を短縮し、冷蔵室４の冷却効率を向上することで省エネルギー化が可能となる。
【０１１２】
また、冷媒を効率よく利用することができるので冷媒量を削減でき、特に可燃性自然冷媒（イソブタン，プロパン等）を用いる場合には、その冷媒量削減により、冷媒漏洩時の安全性を高めることが可能となる。
【０１１３】
（実施の形態６）
図１３は本発明の他の実施の形態による冷蔵庫の運転タイムチャートである。
【０１１４】
冷蔵室４と冷凍室６の冷却のタイミングについて図１３のタイムチャートを元に説明する。
【０１１５】
冷凍室６の冷却中に冷蔵室４の温度検知手段が予め設定された所定の温度を越えていることを検知すると、流路制御手段１２は第一の状態となり、第一の蒸発器３に冷媒が流れ、第一の送風手段１３を運転し、第二の送風手段１４を停止し、冷蔵室４の冷却を開始する（Ｔ４１）。
【０１１６】
冷蔵室の冷却を開始すると同時に、除霜ヒータ２４を所定の時間（Ｔｂ２）のあいだデューティ制御等により断続的に通電する。
【０１１７】
冷蔵室４の冷却中に冷凍室６の温度検知手段が予め設定された所定の温度を越えていることを検知すると、流路制御手段１２は第二の状態となり第二の蒸発器５に冷媒が流れ、第一の送風手段１３を停止し、第二の送風手段１４を運転し、冷凍室６の冷却を開始する（Ｔ４２）。
【０１１８】
以上の動作を繰り返し、流路制御手段１２により冷媒の流れを切り替えることで冷蔵室４と冷凍室６を交互に冷却し、冷蔵室４と冷凍室６の温度検知手段が予め設定された所定の温度より低いことを検知すると、流路制御手段は第三の状態となり、第一の送風手段１３と第二の送風手段１４をともに停止し、圧縮機１を停止する（Ｔ４３）。
【０１１９】
冷蔵室４の冷却を行う際に、除霜ヒータ２４に通電することにより、冷蔵室４の冷却中に第二の蒸発器５の温度及び圧力の上昇を促進できるため、第二の蒸発器５に滞留した冷媒を回収する効率を向上させることができ、第一の蒸発器の冷媒循環量不足の時間を短縮することができるが、例えば冷凍室６内及び冷蔵室４内の温度差が小さい場合のように、負荷状態によっては冷蔵室４の冷却時に所定時間のあいだ連続して通電しなくても、冷媒循環量不足の時間が充分に短い場合がある。このような場合には、ポンプダウン後の冷蔵室４の冷却時の除霜ヒータ２３の通電を、例えばデューティ制御等により断続的に行うことにより、除霜ヒータ２３による消費電力を低減することが可能となる。
【０１２０】
また、冷媒を効率よく利用することができるので冷媒量を削減でき、特に可燃性自然冷媒（イソブタン，プロパン等）を用いる場合には、その冷媒量削減により、冷媒漏洩時の安全性を高めることが可能となる。
【０１２１】
（実施の形態７）
図１４は本発明の他の実施の形態による冷蔵庫の運転タイムチャートである。
【０１２２】
冷蔵室４と冷凍室６の冷却のタイミングについて図１４のタイムチャートを元に説明する。
【０１２３】
冷凍室６の冷却中に冷蔵室４の温度検知手段が予め設定された所定の温度を越えていることを検知すると、流路制御手段１２は第一の状態となり、第一の蒸発器３に冷媒が流れ、第一の送風手段１３を運転し、冷蔵室４の冷却を開始する（Ｔ５１）。
【０１２４】
冷蔵室の冷却を開始後、所定の時間（Ｔｂ３）のあいだ第二の送風手段１４は運転する。
【０１２５】
冷蔵室４の冷却中に冷凍室６の温度検知手段が予め設定された所定の温度を越えていることを検知すると、流路制御手段１２は第二の状態となり第二の蒸発器５に冷媒が流れ、第一の送風手段１３を停止し、第二の送風手段１４を運転し、冷凍室６の冷却を開始する（Ｔ５２）。
【０１２６】
以上の動作を繰り返し、流路制御手段１２により冷媒の流れを切り替えることで冷蔵室４と冷凍室６を交互に冷却し、冷蔵室４と冷凍室６の温度検知手段が予め設定された所定の温度より低いことを検知すると、流路制御手段は第三の状態となり、第一の送風手段１３と第二の送風手段１４をともに停止し、圧縮機１を停止する（Ｔ５３）。
【０１２７】
冷蔵室４の冷却を行う際に、所定時間のあいだ第二の送風手段１４を運転することにより、冷蔵室４の冷却中に第二の蒸発器５の温度及び圧力の上昇を促進できるため、第二の蒸発器５に滞留した冷媒を回収する効率を向上させることができ、第一の蒸発器５の冷媒循環量不足の時間を短縮し、冷蔵室４の冷却効率を向上することで省エネルギー化が可能となる。
【０１２８】
また、冷媒を効率よく利用することができるので冷媒量を削減でき、特に可燃性自然冷媒（イソブタン，プロパン等）を用いる場合には、その冷媒量削減により冷媒漏洩時の安全性を高めることが可能となる。
【０１２９】
（実施の形態８）
図１５は本発明の他の実施の形態による冷蔵庫の冷却サイクル概略図である。
【０１３０】
２５は低圧容器型の圧縮機である。
【０１３１】
冷却サイクルの冷媒に図示しない可燃性自然冷媒（イソブタン，プロパン等）を用いている。
【０１３２】
冷蔵室４の冷却時における冷媒循環量不足を解消することにより、冷蔵室４の冷却効率を向上することで、冷媒量を削減でき、特に可燃性自然冷媒（イソブタン，プロパン等）を用いる場合には、その冷媒量削減により、冷媒漏洩時の安全性を高めることが可能となる。
【０１３３】
【発明の効果】
以上のように本発明によれば、冷蔵室と冷凍室の冷却を切り替えて行う冷却システムの冷媒量削減と効率向上を行うことで、省エネルギーが可能である冷蔵庫を提供することができる。
【０１３４】
また、上記の結果より冷媒を効率よく利用することができるので冷媒量を削減でき、特に可燃性自然冷媒（イソブタン，プロパン等）を用いる場合には、その冷媒量削減により、冷媒漏洩時の安全性を高めることが可能な冷蔵庫を提供することができる。
【図面の簡単な説明】
【図１】本発明の一実施の形態による冷蔵庫の冷却サイクル図
【図２】同実施の形態による流路制御手段の概略断面図
【図３】同実施の形態による第一の蒸発器の冷媒封入量特性図
【図４】同実施の形態による第二の蒸発器の冷媒封入量特性図
【図５】同実施の形態による冷蔵庫の運転タイムチャート
【図６】本発明の他の実施の形態による第一，第二の蒸発器の正面図
【図７】本発明の他の実施の形態による冷蔵庫の冷却サイクル図
【図８】同実施の形態による冷蔵庫の運転タイムチャート
【図９】本発明の他の実施の形態による冷蔵庫の冷却サイクル図
【図１０】同実施の形態による冷蔵庫の運転タイムチャート
【図１１】本発明の他の実施の形態による冷蔵庫の冷却サイクル図
【図１２】同実施の形態による冷蔵庫の運転タイムチャート
【図１３】本発明の他の実施の形態による冷蔵庫の運転タイムチャート
【図１４】本発明の他の実施の形態による冷蔵庫の運転タイムチャート
【図１５】本発明の他の実施の形態による冷蔵庫の冷却サイクル図
【図１６】従来の冷蔵庫の冷却サイクル図
【符号の説明】
１圧縮機
２凝縮器
３第一の蒸発器
４冷蔵室
５第二の蒸発器
６冷凍室
７第一の減圧手段
８第二の減圧手段
９逆止弁
１０第一の開閉弁
１１第二の開閉弁
１２流路制御手段
１３第一の送風手段
１４第二の送風手段
１５冷蔵庫箱体
１６機械室
１７第一の位置
１８第二の位置
１９第三の位置
２０回転軸
２１シール部材
２２シリンダ
２３能力可変型の圧縮機
２４除霜ヒータ
２５低圧容器型の圧縮機[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement in efficiency of a cooling system that cools a freezer compartment and a refrigerator compartment independently of each other, reduction in the amount of refrigerant, and improvement in safety.
[0002]
[Prior art]
FIG. 16 shows a cooling cycle diagram of a refrigerator disclosed in Japanese Patent Publication No. 62-22396 as an example of a conventional cooling cycle and a refrigerator.
[0003]
Reference numeral 1 denotes a compressor, 2 a condenser, 3 a first evaporator disposed in the refrigerator compartment 4, and 5 a second evaporator disposed in the freezer compartment 6.
[0004]
Reference numeral 7 denotes a first capillary disposed upstream of the refrigerant circuit of the first evaporator 3 for cooling the refrigerator compartment, and reference numeral 8 denotes an upstream side of the refrigerant circuit of the second evaporator 5 for cooling the freezer compartment. 9 is a check valve provided on the downstream side of the second evaporator 5 for cooling the freezer compartment.
[0005]
Reference numeral 10 denotes a first on-off valve disposed on the downstream side of the refrigerant circuit of the first evaporator 3, and reference numeral 11 denotes a second on-off valve provided on the upstream side of the refrigerant circuit of the second capillary 8.
[0006]
About the refrigerator of the prior art example comprised as mentioned above, the operation | movement is demonstrated below.
[0007]
The operation of the refrigeration cycle is performed as follows. First, the refrigerant compressed by the compressor 1 is condensed and liquefied by the condenser 2. The condensed refrigerant is depressurized by the first capillary 7 or the second capillary 8, flows into the first evaporator 3 and the second evaporator 5, and is evaporated and evaporated, and then returns to the compressor 1 again. Inhaled.
[0008]
Each chamber is cooled by heat exchange between the air in the first and second evaporators 3 and 5 and the refrigerator compartment 4 and the freezer compartment 6 which have become relatively low temperatures due to the evaporation of the refrigerant.
[0009]
The cooling operation of the refrigerator is performed as follows by the temperature detection means and control means of each room (not shown).
[0010]
When each temperature detection means in the refrigerator compartment 4 and the freezer compartment 6 detects a temperature means having a predetermined value or more, the compressor 1 is activated and the refrigeration cycle is operated. The first on-off valve 10 is opened and the second on-off valve 11 is closed until the temperature detecting means of the refrigerator compartment 4 becomes a predetermined value or less.
[0011]
Thus, the refrigerant flows only to the first evaporator 3 without flowing into the second evaporator 5. At this time, the evaporating temperature of the refrigeration cycle is set to −5 to 0 ° C. when the temperature setting of the refrigerator compartment 4 is about 5 ° C., and 2 to 2 with respect to the normal evaporating temperature of −30 to −25 ° C. The compressor can be operated with a coefficient of performance of 5 times.
[0012]
When the refrigerator compartment 4 is cooled to lower the temperature and the temperature detecting means detects a predetermined value or less, the first on-off valve 10 is closed and the second on-off valve 11 is opened.
[0013]
Thereby, a refrigerant | coolant flows in into the 2nd evaporator 5, and the freezer compartment 6 is cooled. The evaporating temperature of the refrigeration cycle at this time is cooled at a normal evaporating temperature (-30 to -25 [deg.] C.) with respect to the temperature setting of the freezer compartment of about -18 [deg.] C.
[0014]
As described above, the refrigerant supply time to the evaporator is distributed between the refrigerator compartment 4 and the freezer compartment 6 and is alternately and repeatedly cooled. Therefore, when the refrigerator compartment 4 is cooled, the refrigerant is independently supplied to the first evaporator. By circulating, a low pressure control valve is unnecessary and a high evaporation temperature (−5 to 0 ° C.) is possible, the compression ratio of the compressor 1 can be reduced, and the operation is performed with a high coefficient of performance to improve efficiency. .
[0015]
Furthermore, the check valve 9 prevents the refrigerant from flowing into the second evaporator 5 because the evaporation temperature during the cooling of the refrigerator compartment 4 is high.
[0016]
When the freezer compartment 6 is cooled, the amount of refrigerant is smaller than that during the cooling of the refrigerator compartment 4, so that the amount of refrigerant is usually excessive. However, since the first on-off valve 10 is provided on the downstream side of the first evaporator 3 and is closed, the refrigerant can be stored in the first evaporator 3 and the amount of refrigerant can be adjusted.
[0017]
[Problems to be solved by the invention]
In the above-described conventional refrigerator, the refrigerant supply time to the evaporator is distributed between the refrigerator compartment 4 and the freezer compartment 6 and is alternately and repeatedly cooled, whereby the refrigerating cycle at the time of cooling the refrigerator compartment 4 is reduced. It is possible to operate at a relatively high evaporation temperature (−5 to 0 ° C.) with a good coefficient of performance.
[0018]
However, the evaporation temperature (−30 to −25 ° C.) of the second evaporator 5 disposed in the freezer compartment 6 is equal to the evaporation temperature (− of the first evaporator 3 disposed in the refrigerator compartment 4). Compared to 5 to 0 ° C.), the temperature is considerably lower and the pressure is also lower.
[0019]
Further, during the cooling of the refrigerator compartment 4, the temperature of the first evaporator 3 disposed in the refrigerator compartment 4 is −5 to 0 ° C., but the temperature in the freezer compartment 6 is as low as about −18 ° C., for example. Therefore, the temperature of the second evaporator 5 disposed in the freezer compartment 6 is also about −18 ° C., and the temperature of the second evaporator 5 is considerably higher than the temperature of the first evaporator 3. Since it is low, the pressure is also low, so that the refrigerant staying in the second evaporator 5 is unlikely to flow out of the second evaporator 5. As a result, sufficient refrigerant is not supplied to the first evaporator 3, and the refrigerant circulation amount becomes insufficient, and the cooling efficiency of the refrigerator compartment 4 is lowered.
[0020]
In particular, when the amount of refrigerant required for cooling the refrigerator compartment 4 is larger than the amount of refrigerant required for cooling the freezer compartment 6, the refrigerant compartment 4 is disposed in the refrigerator compartment 6 when the refrigerator compartment 4 is cooled. Since all of the refrigerant that has accumulated in the low-temperature, low-pressure second evaporator 5 must be recovered from the first evaporator 3, sufficient refrigerant is not supplied to the first evaporator 3, and the refrigerant circulation amount The tendency to become insufficient and the cooling efficiency of the refrigerator compartment 4 to decrease becomes strong.
[0021]
Further, as a measure for preventing the cooling efficiency from being lowered due to insufficient refrigerant circulation amount when the refrigerator compartment 4 is cooled, a refrigerant storage means is provided on the outlet side of the first evaporator 3 or the outlet side of the second evaporator 5. However, it is possible to enclose a refrigerant more than necessary, but this method increases the amount of refrigerant present in the cooling cycle, so there is a high risk of refrigerant leakage when using a flammable natural refrigerant. .
[0022]
The present invention solves the above-described conventional problems, and an object of the present invention is to provide a refrigerator capable of saving energy by improving the efficiency of a cooling system that switches between cooling of a refrigerator compartment and a freezer compartment. And
[0023]
Moreover, since the refrigerant can be used efficiently from the above results, the amount of the refrigerant can be reduced. Especially when a flammable natural refrigerant (isobutane, propane, etc.) is used, the refrigerant amount is reduced, so that the safety at the time of refrigerant leakage is reduced. It aims at providing the refrigerator which can improve the property.
[0024]
[Means for Solving the Problems]
  To achieve this object, the refrigerator of the present invention includes a compressor, a condenser, a flow path control means, a first pressure reducing means, a first evaporator disposed in a refrigerator compartment, and a first evaporator. Air blowing means, a second pressure reducing means, a second evaporator disposed in the freezer compartment, a second air blowing means, and a check valve, the compressor, the condenser, and the flow The path control means, the first pressure reducing means, and the first evaporator form a refrigerating chamber side cooling circuit, and the first pressure reducing means and the first evaporator are arranged in parallel with each other. A second pressure reducing means, the second evaporator, and the check valve, and the compressor, the condenser, the flow path control means, the second pressure reducing means, the second evaporator, and the A freezer compartment side cooling circuit is formed with the check valve, and the flow control means switches the flow of the refrigerant to each cooling circuit, The cooling of the serial freezer compartment is intended to carry out independently of each other,By making the capacity in the pipe constituting the first evaporator smaller than the capacity in the pipe constituting the second evaporator,The refrigerant quantity required for the refrigerator compartment cooling circuit for cooling the refrigerator compartment is smaller than the refrigerant quantity necessary for the freezer compartment side cooling circuit for cooling the freezer compartment.The compressor is of a variable capacity type, and when the refrigerator is started to cool, the compressor is operated at a higher rotational speed than the normal rotational speed for a predetermined time, so that the refrigerator is cooled to the refrigerator. When switching to cooling of the chamber, a part of the refrigerant staying in the second evaporator was circulated to the first evaporator to secure a necessary amount of refrigerant for cooling the refrigerator compartmentIt is characterized by that.
[0026]
Moreover, the amount of pressure reduction by the first pressure reduction means is 0.2 MPa or more and 0.5 MPa or less.
[0028]
In addition, a defrost heater that periodically defrosts the second evaporator is provided, and the defrost heater is energized for a predetermined time when the refrigerator is started to cool.
[0029]
In addition, a defrost heater that periodically defrosts the second evaporator is provided, and when the refrigerator is started, the defrost heater is intermittently energized for a predetermined time.
[0030]
Furthermore, when the cooling of the refrigerator compartment is started, the second air blowing means is operated for a predetermined time.
[0031]
The compressor is a low-pressure vessel type, and is characterized in that a flammable natural refrigerant (isobutane, propane, etc.) is used as a refrigerant in the cooling cycle.
[0032]
According to the present invention, it is possible to provide a refrigerator capable of saving energy by reducing the amount of refrigerant and improving the efficiency of a cooling system that switches between cooling of a refrigerator compartment and a freezer compartment.
[0033]
Moreover, since the refrigerant can be used efficiently from the above results, the amount of the refrigerant can be reduced. Especially when a flammable natural refrigerant (isobutane, propane, etc.) is used, the refrigerant amount is reduced, so that the safety at the time of refrigerant leakage is reduced. It is possible to provide a refrigerator capable of enhancing the performance.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
  The invention according to claim 1 of the present invention includes a compressor, a condenser, a flow path control means, a first pressure reducing means, a first evaporator disposed in a refrigerator compartment, The compressor, the condenser, and the flow path are provided with a blowing means, a second decompression means, a second evaporator disposed in the freezer compartment, a second blowing means, and a check valve. The control means, the first pressure reducing means, and the first evaporator form a refrigerating chamber side cooling circuit, and the second pressure reduction means and the first evaporator are arranged in parallel with each other. The decompression means, the second evaporator, and the check valve are connected, and the compressor, the condenser, the flow path control means, the second decompression means, the second evaporator, and the reverse A freezer compartment side cooling circuit is formed with the stop valve, and the flow control means switches the flow of the refrigerant to each cooling circuit, whereby the refrigerator compartment and the freezer compartment And it performs cooling independently of each other,By making the capacity in the pipe constituting the first evaporator smaller than the capacity in the pipe constituting the second evaporator,The refrigerant quantity required for the refrigerator compartment cooling circuit for cooling the refrigerator compartment is smaller than the refrigerant quantity necessary for the freezer compartment side cooling circuit for cooling the freezer compartment.The compressor is of a variable capacity type, and when the refrigerator is started to cool, the compressor is operated at a higher rotational speed than the normal rotational speed for a predetermined time, so that the refrigerator is cooled to the refrigerator. When switching to cooling of the chamber, a part of the refrigerant staying in the second evaporator was circulated to the first evaporator to secure a necessary amount of refrigerant for cooling the refrigerator compartmentIt is characterized by that.
[0035]
With the above configuration, the amount of refrigerant necessary for cooling the refrigerator compartment is small compared to the amount of refrigerant necessary for cooling the freezer compartment. If a part of the refrigerant staying in the evaporator circulates to the first evaporator, the amount of refrigerant necessary for cooling the refrigeration room can be secured. Energy efficiency can be saved by improving the cooling efficiency.
[0036]
  Moreover, since the refrigerant can be used efficiently from the above results, the amount of the refrigerant can be reduced. Especially when a flammable natural refrigerant (isobutane, propane, etc.) is used, the refrigerant amount is reduced, so that the safety at the time of refrigerant leakage is reduced. It becomes possible to improve the nature.
In the cooling system, the smaller the capacity in the piping that constitutes the evaporator, the more the required amount of refrigerant tends to decrease, so the capacity in the piping that constitutes the first evaporator is in the piping that constitutes the second evaporator. When the capacity is small compared to the capacity of the refrigerator, the amount of refrigerant necessary for cooling the refrigerator compartment tends to be smaller than the amount of refrigerant necessary for cooling the freezer compartment. In addition, if a part of the refrigerant staying in the low-temperature, low-pressure second evaporator is circulated to the second evaporator, the amount of refrigerant necessary for cooling the refrigerator compartment can be secured. It is possible to save energy by eliminating the shortage of circulation and improving the cooling efficiency of the refrigerator compartment.
When the refrigerator is started to cool, the compressor is operated at a higher rotational speed than the normal rotational speed for a predetermined time, thereby improving the recovery capability of the refrigerant accumulated in the low-temperature, low-pressure second evaporator. Since a large amount of refrigerant can be pushed out to the first evaporator with a strong force, the refrigerant circulation rate is not insufficient, and the cooling efficiency of the refrigerator compartment can be improved.
[0039]
  Claim2The invention described in 1 is characterized in that the amount of pressure reduction by the first pressure reducing means is 0.2 MPa or more and 0.5 MPa or less.
[0040]
By reducing the pressure reduction amount by the first pressure reducing means to 0.2 MPa or more and 0.5 MPa or less, which is smaller than the normal pressure reduction amount (about 0.6 MPa), the resistance when the refrigerant passes through the first pressure reducing means is small, and the refrigerant When the cooling chamber is started to cool, the refrigerant quickly moves to the first evaporator through the first pressure reducing means having a low resistance, so that the refrigerant circulation amount is not insufficient and the cooling chamber is cooled. Efficiency can be improved.
[0043]
  Claim3The invention described in 1 is characterized in that a defrost heater that periodically defrosts the second evaporator is provided, and the defrost heater is energized for a predetermined time when cooling of the refrigerator compartment is started. .
[0044]
When cooling the refrigerator compartment, the temperature and pressure of the second evaporator can be increased during cooling of the refrigerator compartment by energizing the defrost heater for a predetermined time. The efficiency of collecting the staying refrigerant can be improved, the time of the refrigerant circulation shortage of the first evaporator can be shortened, and the cooling efficiency of the refrigerator compartment can be improved.
[0045]
  Claim4The invention described inProvide a defrost heater that periodically defrosts the second evaporator,When starting to cool the refrigerator compartment, the defrost heater is energized intermittently for a predetermined time.
[0046]
When cooling the refrigerating chamber, by energizing the defrost heater, the temperature and pressure of the second evaporator can be increased during the cooling of the refrigerating chamber, so that the refrigerant that has accumulated in the second evaporator is removed. The recovery efficiency can be improved, and the refrigerant circulation amount shortage time of the first evaporator can be shortened, but depending on the load condition, for example, when the temperature difference between the freezer compartment and the refrigerator compartment is small Even if the energization is not continuously performed for a predetermined time when the refrigerator compartment is cooled after the pump is down, there may be a case where the refrigerant circulation shortage time is sufficiently short. In such a case, power consumption by the defrost heater can be reduced by intermittently energizing the defrost heater during cooling of the refrigerator compartment after the pump is down, for example, by duty control or the like. .
[0047]
  Claim5The invention described in 1 is characterized in that the second air blowing means is operated for a predetermined time when the cooling of the refrigerator compartment is started.
[0048]
When cooling the refrigerating room, by operating the second air blowing means for a predetermined time, the temperature and pressure of the second evaporator can be increased during cooling of the refrigerating room. It is possible to improve the efficiency of collecting the refrigerant staying in the refrigerator, to shorten the time of insufficient refrigerant circulation in the first evaporator, and to provide a refrigerator capable of improving the cooling efficiency of the refrigerator compartment.
[0049]
  Claim6In the invention described in item 1, the compressor is a low-pressure vessel type, and a combustible natural refrigerant (isobutane, propane, or the like) is used as a refrigerant in the cooling cycle.
[0050]
From the above results, by eliminating or mitigating the shortage of refrigerant circulation in the first evaporator when switching from cooling in the freezer to cooling in the refrigerator, the refrigerant can be used efficiently, and in particular, the amount of refrigerant can be reduced. When a flammable natural refrigerant (isobutane, propane, etc.) is used, it is possible to increase the safety at the time of refrigerant leakage by reducing the amount of the refrigerant.
[0051]
Hereinafter, embodiments of the present invention will be described with reference to FIGS. Detailed description of the same configuration as the conventional example is omitted, and the same reference numerals are given.
[0052]
(Embodiment 1)
1 is a cooling cycle diagram of a refrigerator according to an embodiment of the present invention, FIG. 2 is a schematic cross-sectional view of a flow path control means according to the embodiment, and FIG. 3 is a refrigerant filling of a first evaporator according to the embodiment. FIG. 4 is an amount characteristic diagram, FIG. 4 is a refrigerant filling amount characteristic diagram of the second evaporator according to the embodiment, and FIG. 5 is an operation time chart of the refrigerator according to the embodiment.
[0053]
A compressor 1, a condenser 2, a flow path control means 12, a first decompression means 7, a first evaporator 3 disposed in the refrigerator compartment 4, a first blower means 13, A second decompression means 8, a second evaporator 5 disposed in the freezer compartment 6, a second blowing means 14, and a check valve 9 are provided, and the compressor 1, the condenser 2, and the first The first decompression means 7 and the first evaporator 3 form a refrigerating chamber side cooling circuit, and the second decompression means 8 and the first decompression means 8 are arranged in parallel with the first decompression means 7 and the first evaporator 3. The second evaporator 5 and the check valve 9 are connected, and the freezer compartment side cooling circuit is constituted by the compressor 1, the condenser 2, the second pressure reducing means 8, the second evaporator 5 and the check valve 9. Forming.
[0054]
Reference numeral 15 denotes a refrigerator box, in which a refrigerator compartment 4 which is a relatively high temperature compartment is arranged in the upper part, and a freezer compartment 6 which is a relatively low temperature compartment is arranged in the lower part. Insulated from the surroundings. The storage of food and other items is performed through a heat insulating door (not shown).
[0055]
The compressor 1, the condenser 2, and the flow path control means 12 are disposed in the machine room 16 in order to reduce the number of pipe connections in the refrigerator box 15 from the aspect of improving safety when a flammable natural refrigerant is used. ing.
[0056]
The refrigerator compartment 4 and the freezer compartment 6 are respectively provided with temperature detection means (not shown) for detecting the temperature in the compartment, and the compressor 1, the flow path control means 12, the first blower means 13, and the second blower means 14 are provided. Control means (not shown) for controlling.
[0057]
As shown in FIG. 2, the flow path control means 12 is a three-way valve that blocks the flow of refrigerant from the condenser 2 to the second pressure reduction means 8 and opens the flow of refrigerant to the first pressure reduction means 7. (First state), and the flow of the refrigerant from the condenser 2 to the first decompression means 7 is blocked by the first position 17 forming the refrigerating room side cooling circuit, and to the second decompression means 8 By opening the refrigerant flow (second state) and closing the second position 18 forming the freezer compartment side cooling circuit and the outlet side of the condenser 2, the first decompression means 7 and the second decompression A third position 19 is provided for blocking the refrigerant flow to the means 8 and blocking the high-pressure side and the low-pressure side of the cooling cycle (third state). A seal member 21 that is eccentrically fixed to the rotary shaft 20 rotates in the cylinder 22 and stops at the first, second, and third positions, thereby closing the pipes connected to the respective positions. It is. The rotation is performed by drive means and transmission means (not shown). Positioning at each position is controlled by the number of drive pulses of a pulse motor, for example.
[0058]
The required refrigerant amount of the refrigerator compartment side cooling circuit for cooling the refrigerator compartment 4 will be described with reference to FIG.
[0059]
FIG. 3 shows that, for example, when the outside air temperature is about 30 ° C., the flow path control means 12 is in the first state, the refrigerator compartment side cooling circuit for cooling the refrigerator compartment 4 is formed, the compressor 1 and the first air blower The refrigerant inlet temperature and the refrigerant outlet temperature of the first evaporator 3 at the stable time when the refrigerant quantity (refrigerant quantity) enclosed in the refrigerator compartment side cooling circuit is changed while the means 13 is continuously operated. , And the relationship between the temperatures in the refrigerator compartment 4.
[0060]
When the refrigerant filling amount is 40 g, the refrigerant outlet temperature of the first evaporator 3 is higher than the refrigerant inlet temperature, the refrigerant circulation amount is insufficient, the cooling efficiency of the refrigerator compartment 4 is poor, The internal temperature of the refrigerator compartment 4 is also high.
[0061]
When the refrigerant filling amount is 50 g, the refrigerant inlet temperature and the refrigerant outlet temperature of the first evaporator 3 are equal to each other, the refrigerant circulation amount is not excessive and insufficient, the cooling efficiency of the refrigerator compartment 4 is good, and the refrigerator compartment The inside temperature of 4 is also in a low state.
[0062]
Generally, a refrigerant storage means is provided on the refrigerant outlet side of the first evaporator 3 in order to prevent a liquid back phenomenon to the compressor 1 in a transient operation state such as when the compressor 1 is started. While the refrigerant filling amount is between 60 g and 80 g, the refrigerant filling amount is in an overfilled state, but due to the storage effect (margin) by this refrigerant storage means, the refrigerant inlet temperature and the refrigerant outlet of the first evaporator 3 The temperature is maintained at an equivalent temperature, the cooling efficiency of the refrigerator compartment 4 is good, and the temperature inside the refrigerator compartment 4 is kept low. When the amount of refrigerant filled exceeds 90 g, there is a refrigerant exceeding the storage effect (margin) by the refrigerant storage means, causing a liquid back phenomenon that the liquid refrigerant is sucked into the compressor 1, and the first evaporation The evaporation temperature of the vessel 3 rises and the cooling efficiency of the refrigerator compartment 4 also deteriorates.
[0063]
The refrigerant filling amount (in this case, 50 g) when the refrigerant circulation amount of the refrigerating chamber side cooling circuit for cooling the refrigerating chamber 4 is not excessive or insufficient is set as a necessary refrigerant amount for cooling the refrigerating chamber 4.
[0064]
FIG. 4 shows that, for example, when the outside air temperature is about 30 ° C., the flow path control means 12 is in the second state, the freezer compartment side cooling circuit for cooling the freezer compartment 6 is formed, the compressor 1 and the second air blower The refrigerant inlet temperature and the refrigerant outlet temperature of the second evaporator 5 at the stable time when the refrigerant quantity (refrigerant quantity) enclosed in the freezer compartment side cooling circuit is changed while the means 14 is continuously operated. , And the relationship between the temperatures in the freezer compartment 6.
[0065]
When the refrigerant filling amount is 70 g, the refrigerant outlet temperature of the second evaporator 5 is higher than the refrigerant inlet temperature, the refrigerant circulation amount is insufficient, the cooling efficiency of the freezer compartment 5 is poor, The internal temperature of the freezer compartment 5 is also high.
[0066]
When the refrigerant charging amount is 80 g, the refrigerant inlet temperature and the refrigerant outlet temperature of the second evaporator 5 are equal to each other, the refrigerant circulation amount is not excessive and insufficient, the cooling efficiency of the freezer compartment 6 is good, and the freezer compartment The inside temperature of 6 is also in a low state.
[0067]
Generally, in order to prevent a liquid back phenomenon to the compressor 1 in a transient operation state such as when the compressor 1 is started, a refrigerant storage means is provided on the refrigerant outlet side of the second evaporator 5. While the refrigerant filling amount is between 90 g and 110 g, the refrigerant filling amount is in an overfilled state, but due to the storage effect (margin) by this refrigerant storage means, the refrigerant inlet temperature and the refrigerant outlet of the second evaporator 5 The temperature is maintained at an equivalent temperature, the cooling efficiency of the freezer compartment 6 is good, and the internal temperature of the freezer compartment 6 is kept low. When the amount of refrigerant filled exceeds 120 g, there is a refrigerant exceeding the storage effect (margin) by the refrigerant storage means, causing the liquid back phenomenon that the liquid refrigerant is sucked into the compressor 1, and the second evaporation The evaporation temperature of the vessel 5 rises and the cooling efficiency of the freezer compartment 6 also deteriorates.
[0068]
The refrigerant filling amount (80 g in this case) when the refrigerant circulation amount of the freezer compartment side cooling circuit for cooling the freezer compartment 6 is not excessive or insufficient is set as the necessary refrigerant amount for cooling the freezer compartment 6.
[0069]
As described above, the amount of refrigerant necessary for cooling the refrigerator compartment 4 (50 g in this example) is smaller than the amount of refrigerant necessary for cooling the freezer compartment 6 (80 g in this example). .
[0070]
About the refrigerator comprised as mentioned above, the timing of the cooling of the refrigerator compartment 4 and the freezer compartment 6 is demonstrated based on the time chart of FIG.
[0071]
While the freezer compartment 6 is being cooled, the flow path control means 12 is in the second state, the refrigerant flows to the second evaporator 5, and the second air blowing means 14 is operating.
[0072]
The high-temperature and high-pressure refrigerant discharged by the operation of the compressor 1 is condensed and liquefied by the condenser 2 and is reduced in pressure by the second pressure-reducing means 8 via the flow path control means 12 and then to the second evaporator 5. The refrigerant in the second evaporator 5 evaporates by the heat exchange with the air in the freezer compartment 6 by the operation of the second air blowing means 14, and the heat exchanged air has a lower temperature. It becomes air and cools the freezer compartment 6.
[0073]
When it is detected that the temperature detection means of the refrigerator compartment 4 exceeds a preset predetermined temperature during the cooling of the freezer compartment 6, the flow path control means 12 enters the first state, and the first evaporator 3 A refrigerant | coolant flows, the 1st ventilation means 13 is drive | operated, and the 2nd ventilation means 14 is stopped (T01).
[0074]
The refrigerant is decompressed by the first decompression means 7 through the compressor 1, the condenser 2, the flow path control means 12, and then flows into the first evaporator 3, and the first air blowing means 13 is operated. By exchanging heat with the air in the refrigerator compartment 4, the refrigerant in the first evaporator 3 evaporates, and the heat-exchanged air becomes cooler air and cools the refrigerator compartment 4.
[0075]
When the temperature detecting means of the freezer compartment 6 detects that the temperature in the freezer compartment 6 exceeds a predetermined temperature during the cooling of the refrigerator compartment 4, the flow path control means 12 enters the second state and the second evaporator 5 receives the refrigerant. Flows, the first blowing means 13 is stopped, the second blowing means 14 is operated, and cooling of the freezer compartment 6 is started (T02).
[0076]
The refrigerant is decompressed by the second decompression means 8 through the compressor 1, the condenser 2, and the second on-off valve 11, and then flows into the second evaporator 5 to operate the second blower fan 14. Thus, by exchanging heat with the air in the freezer compartment 6, the refrigerant in the second evaporator 5 evaporates, and the heat-exchanged air becomes cooler air and cools the freezer compartment 6.
[0077]
The above operation is repeated, and the refrigerant flow is switched by the flow path control means 12 so that the refrigerator compartment 4 and the freezer compartment 6 are alternately cooled, and the temperature detecting means of the refrigerator compartment 4 and the freezer compartment 6 is set to a predetermined value. When it is detected that the temperature is lower than the temperature, the flow path control unit enters the third state, stops both the first blower unit 13 and the second blower unit 14, and stops the compressor 1 (T03).
[0078]
As described above, when cooling the refrigerator compartment 4, if a part of the refrigerant staying in the low-temperature, low-pressure second evaporator 5 circulates in the first evaporator 3, the refrigerator compartment is cooled. Therefore, it is possible to save energy by eliminating the circulation amount shortage of the first evaporator 3 and improving the cooling efficiency of the refrigerator compartment 4.
[0079]
Moreover, since the refrigerant can be used efficiently from the above results, the amount of the refrigerant can be reduced. Especially when a flammable natural refrigerant (isobutane, propane, etc.) is used, the refrigerant amount is reduced, so that the safety at the time of refrigerant leakage is reduced. It becomes possible to improve the nature.
[0080]
Although the flow path control means 12 is a three-way valve, the same effect can be obtained even if a two-way valve is provided on the inlet side of the first pressure reducing means 7 and the second pressure reducing means 8.
[0081]
(Embodiment 2)
FIG. 6A is a front view of a first evaporator according to another embodiment, and FIG. 6B is a front view of a second evaporator according to the embodiment.
[0082]
As shown in FIG. 6, the length of the pipe constituting the first evaporator 3 is L1, the inner diameter is D1, the internal capacity is V1, the length of the pipe constituting the second evaporator 5 is L2, and the inner diameter. Is D2 and the internal capacity is V2, the internal capacity of the pipes constituting the first evaporator 3 and the second evaporator 5 is V1 = 1 / 4πD1, respectively.²L1, V2 = 1 / 4πD2²The internal capacity V1 of the pipe of the first evaporator 3 and the internal capacity V2 of the pipe of the second evaporator 5 are expressed by L2, and are configured such that V1 <V2.
[0083]
Since the required amount of refrigerant tends to decrease as the capacity in the pipe constituting the evaporator in the cooling system decreases, the capacity in the pipe constituting the first evaporator 3 constitutes the second evaporator 5. When the capacity is small compared to the capacity in the pipe, the amount of refrigerant necessary for cooling the refrigerator compartment 4 tends to be smaller than the amount of refrigerant necessary for cooling the freezer compartment 6, and the refrigerator compartment 4 When cooling the refrigerant, if a part of the refrigerant staying in the low-temperature, low-pressure second evaporator 5 is recovered, the amount of refrigerant necessary to cool the refrigerator compartment 4 can be secured. Refrigerant recovery efficiency can be improved by pumping down to operate the compressor 1 with the outlet side flow path closed by the flow path control means 12, and energy can be saved by improving the cooling efficiency of the refrigerator compartment 4. It becomes.
[0084]
Moreover, since the refrigerant can be used efficiently from the above results, the amount of the refrigerant can be reduced. Especially when a flammable natural refrigerant (isobutane, propane, etc.) is used, the refrigerant amount is reduced, so that the safety at the time of refrigerant leakage is reduced. It becomes possible to improve the nature.
[0085]
(Embodiment 3)
FIG. 7 is a cooling cycle diagram of a refrigerator according to another embodiment of the present invention, and FIG. 8 is an operation time chart of the refrigerator according to the embodiment.
[0086]
As shown in FIG. 7, the pressure reduction amount R1 by the first pressure reduction means 7 is 0.2 MPa to 0.5 MPa, and the pressure reduction amount R2 by the second pressure reduction means 8 which is a normal pressure reduction amount is about 0.6 MPa. <R2 is configured.
[0087]
The cooling timing of the refrigerator compartment 4 and the freezer compartment 6 will be described based on the time chart of FIG.
[0088]
When it is detected that the temperature detection means of the refrigerator compartment 4 exceeds a preset predetermined temperature during the cooling of the freezer compartment 6, the flow path control means 12 enters the first state, and the first evaporator 3 A refrigerant | coolant flows, the 1st ventilation means 13 is drive | operated, the 2nd ventilation means 14 is stopped, and cooling of the refrigerator compartment 4 is started (T11).
[0089]
When the temperature detecting means of the freezer compartment 6 detects that the temperature in the freezer compartment 6 exceeds a predetermined temperature during the cooling of the refrigerator compartment 4, the flow path control means 12 enters the second state and the second evaporator 5 receives the refrigerant. Flows, the first blowing means 13 is stopped, the second blowing means 14 is operated, and cooling of the freezer compartment 6 is started (T12).
[0090]
The above operation is repeated, and the refrigerant flow is switched by the flow path control means 12 so that the refrigerator compartment 4 and the freezer compartment 6 are alternately cooled, and the temperature detecting means of the refrigerator compartment 4 and the freezer compartment 6 is set to a predetermined value. When it is detected that the temperature is lower than the temperature, the flow path control unit enters the third state, stops both the first blower unit 13 and the second blower unit 14, and stops the compressor 1 (T13).
[0091]
The amount of pressure reduced by the first pressure reducing means 7 is set to 0.2 MPa to 0.5 MPa, which is smaller than the normal pressure reducing amount (about 0.6 MPa) as in the second pressure reducing means 8, so that the refrigerant becomes the first pressure reducing means 7. When the refrigerator compartment 4 is cooled, the refrigerant quickly moves to the first evaporator 3 via the first pressure reducing means 7 having a low resistance. Therefore, the refrigerant circulation amount is not insufficient, and energy saving can be achieved by improving the cooling efficiency of the refrigerator compartment 4.
[0092]
In addition, since the refrigerant can be used efficiently, the amount of refrigerant can be reduced, especially when using flammable natural refrigerants (isobutane, propane, etc.) to increase the safety at the time of refrigerant leakage by reducing the amount of refrigerant. Is possible.
[0093]
Here, the amount of pressure reduction of the pressure reducing means is 1.2 MPa (12 kgf / cm 2) by nitrogen gas at the inlet of the pressure reducing means.²The pressure difference (differential pressure) between the inlet and outlet of the pressure reducing means when the pressure of G) is applied.
[0094]
Moreover, in the state where the pressure reduction amount is 0.2 MPa to 0.5 MPa, the flow rate of nitrogen gas by the pressure reducing means is 12 L / min to 30 L / min.
[0095]
(Embodiment 4)
FIG. 9 is a cooling cycle diagram of a refrigerator according to another embodiment of the present invention, and FIG. 10 is an operation time chart of the refrigerator according to the embodiment.
[0096]
Reference numeral 23 denotes a variable capacity compressor.
[0097]
The cooling timing of the refrigerator compartment 4 and the freezer compartment 6 will be described based on the time chart of FIG.
[0098]
When it is detected that the temperature detection means of the refrigerator compartment 4 exceeds a preset predetermined temperature during the cooling of the freezer compartment 6, the flow path control means 12 enters the first state, and the first evaporator 3 A refrigerant | coolant flows, the 1st ventilation means 13 is drive | operated, the 2nd ventilation means 14 is stopped, and cooling of the refrigerator compartment 4 is started (T21).
[0099]
Simultaneously with the start of cooling of the refrigerator compartment, the compressor 1 is operated for a predetermined time (Tb0) at a higher rotational speed than the normal rotational speed.
[0100]
When the temperature detecting means of the freezer compartment 6 detects that the temperature in the freezer compartment 6 exceeds a predetermined temperature during the cooling of the refrigerator compartment 4, the flow path control means 12 enters the second state and the second evaporator 5 receives the refrigerant. Flows, the first blowing means 13 is stopped, the second blowing means 14 is operated, and cooling of the freezer compartment 6 is started (T22).
[0101]
The above operation is repeated, and the refrigerant flow is switched by the flow path control means 12 so that the refrigerator compartment 4 and the freezer compartment 6 are alternately cooled, and the temperature detecting means of the refrigerator compartment 4 and the freezer compartment 6 is set to a predetermined value. When it is detected that the temperature is lower than the temperature, the flow path control unit enters the third state, stops both the first blower unit 13 and the second blower unit 14, and stops the compressor 1 (T23).
[0102]
When the refrigerator compartment 4 is cooled, the refrigerant can be pushed out to the first evaporator 3 with a strong force by operating the compressor 1 at a higher rotational speed than the normal rotational speed for a predetermined time. Therefore, the refrigerant circulation amount is not insufficient, and energy saving can be achieved by improving the cooling efficiency of the refrigerator compartment 4.
[0103]
In addition, since the refrigerant can be used efficiently, the amount of refrigerant can be reduced, especially when using flammable natural refrigerants (isobutane, propane, etc.) to increase the safety at the time of refrigerant leakage by reducing the amount of refrigerant. Is possible.
[0104]
(Embodiment 5)
FIG. 11 is a cooling cycle diagram of a refrigerator according to another embodiment of the present invention, and FIG. 12 is an operation time chart of the refrigerator according to the embodiment.
[0105]
A defrost heater 24 periodically defrosts the second evaporator 5.
[0106]
The cooling timing of the refrigerator compartment 4 and the freezer compartment 6 is demonstrated based on the time chart of FIG.
[0107]
When it is detected that the temperature detection means of the refrigerator compartment 4 exceeds a preset predetermined temperature during the cooling of the freezer compartment 6, the flow path control means 12 enters the first state, and the first evaporator 3 A refrigerant | coolant flows, the 1st ventilation means 13 is drive | operated, the 2nd ventilation means 14 is stopped, and cooling of the refrigerator compartment 4 is started (T31).
[0108]
Simultaneously with the start of cooling of the refrigerator compartment, the defrost heater 24 is energized for a predetermined time (Tb1).
[0109]
When the temperature detecting means of the freezer compartment 6 detects that the temperature in the freezer compartment 6 exceeds a predetermined temperature during the cooling of the refrigerator compartment 4, the flow path control means 12 enters the second state and the second evaporator 5 receives the refrigerant. Flows, the first blowing means 13 is stopped, the second blowing means 14 is operated, and cooling of the freezer compartment 6 is started (T32).
[0110]
The above operation is repeated, and the refrigerant flow is switched by the flow path control means 12 so that the refrigerator compartment 4 and the freezer compartment 6 are alternately cooled, and the temperature detecting means of the refrigerator compartment 4 and the freezer compartment 6 is set to a predetermined value. When it is detected that the temperature is lower than the temperature, the flow path control unit enters the third state, stops both the first blower unit 13 and the second blower unit 14, and stops the compressor 1 (T33).
[0111]
When the refrigerator compartment 4 is cooled, the temperature and pressure of the second evaporator 5 can be increased during the cooling of the refrigerator compartment 4 by energizing the defrost heater 24 for a predetermined time. The efficiency of collecting the refrigerant staying in the evaporator 5 can be improved, the time of the refrigerant circulation shortage of the first evaporator 3 can be shortened, and the cooling efficiency of the refrigerator compartment 4 can be improved to save energy. It becomes.
[0112]
In addition, since the refrigerant can be used efficiently, the amount of refrigerant can be reduced, especially when using flammable natural refrigerants (isobutane, propane, etc.) to increase the safety at the time of refrigerant leakage by reducing the amount of refrigerant. Is possible.
[0113]
(Embodiment 6)
FIG. 13 is an operation time chart of the refrigerator according to another embodiment of the present invention.
[0114]
The cooling timing of the refrigerator compartment 4 and the freezer compartment 6 is demonstrated based on the time chart of FIG.
[0115]
When it is detected that the temperature detection means of the refrigerator compartment 4 exceeds a preset predetermined temperature during the cooling of the freezer compartment 6, the flow path control means 12 enters the first state, and the first evaporator 3 A refrigerant | coolant flows, the 1st ventilation means 13 is drive | operated, the 2nd ventilation means 14 is stopped, and cooling of the refrigerator compartment 4 is started (T41).
[0116]
Simultaneously with the start of cooling of the refrigerator compartment, the defrost heater 24 is intermittently energized by duty control or the like for a predetermined time (Tb2).
[0117]
When the temperature detecting means of the freezer compartment 6 detects that the temperature in the freezer compartment 6 exceeds a predetermined temperature during the cooling of the refrigerator compartment 4, the flow path control means 12 enters the second state and the second evaporator 5 receives the refrigerant. Flows, the first blowing means 13 is stopped, the second blowing means 14 is operated, and cooling of the freezer compartment 6 is started (T42).
[0118]
The above operation is repeated, and the refrigerant flow is switched by the flow path control means 12 so that the refrigerator compartment 4 and the freezer compartment 6 are alternately cooled, and the temperature detecting means of the refrigerator compartment 4 and the freezer compartment 6 is set to a predetermined value. When it is detected that the temperature is lower than the temperature, the flow path control unit enters the third state, stops both the first blowing unit 13 and the second blowing unit 14, and stops the compressor 1 (T43).
[0119]
When the refrigerator compartment 4 is cooled, by energizing the defrost heater 24, the temperature and pressure of the second evaporator 5 can be increased during the cooling of the refrigerator compartment 4, so that the second evaporator 5 The efficiency of collecting the refrigerant accumulated in the first evaporator can be improved and the time of the refrigerant circulation shortage of the first evaporator can be shortened. However, for example, the temperature difference between the freezer compartment 6 and the refrigerator compartment 4 is small. In some cases, depending on the load state, the refrigerant circulation amount shortage time may be sufficiently short even if the energization is not continuously performed for a predetermined time when the refrigerator compartment 4 is cooled. In such a case, the power consumption by the defrost heater 23 can be reduced by intermittently energizing the defrost heater 23 during cooling of the refrigerator compartment 4 after the pump is down, for example, by duty control or the like. It becomes possible.
[0120]
In addition, since the refrigerant can be used efficiently, the amount of refrigerant can be reduced, especially when using flammable natural refrigerants (isobutane, propane, etc.) to increase the safety at the time of refrigerant leakage by reducing the amount of refrigerant. Is possible.
[0121]
(Embodiment 7)
FIG. 14 is an operation time chart of the refrigerator according to another embodiment of the present invention.
[0122]
The cooling timing of the refrigerator compartment 4 and the freezer compartment 6 is demonstrated based on the time chart of FIG.
[0123]
When it is detected that the temperature detection means of the refrigerator compartment 4 exceeds a preset predetermined temperature during the cooling of the freezer compartment 6, the flow path control means 12 enters the first state, and the first evaporator 3 A refrigerant | coolant flows, the 1st ventilation means 13 is drive | operated and cooling of the refrigerator compartment 4 is started (T51).
[0124]
After starting the cooling of the refrigerator compartment, the second blowing means 14 is operated for a predetermined time (Tb3).
[0125]
When the temperature detecting means of the freezer compartment 6 detects that the temperature in the freezer compartment 6 exceeds a predetermined temperature during the cooling of the refrigerator compartment 4, the flow path control means 12 enters the second state and the second evaporator 5 receives the refrigerant. Flows, the 1st ventilation means 13 is stopped, the 2nd ventilation means 14 is drive | operated, and cooling of the freezer compartment 6 is started (T52).
[0126]
The above operation is repeated, and the refrigerant flow is switched by the flow path control means 12 so that the refrigerator compartment 4 and the freezer compartment 6 are alternately cooled, and the temperature detecting means of the refrigerator compartment 4 and the freezer compartment 6 is set to a predetermined value. When it is detected that the temperature is lower than the temperature, the flow path control unit enters the third state, stops both the first blower unit 13 and the second blower unit 14, and stops the compressor 1 (T53).
[0127]
When cooling the refrigerator compartment 4, by operating the second blowing means 14 for a predetermined time, the temperature and pressure of the second evaporator 5 can be increased during the cooling of the refrigerator compartment 4. The efficiency of collecting the refrigerant accumulated in the second evaporator 5 can be improved, the time of the refrigerant circulation shortage of the first evaporator 5 is shortened, and the cooling efficiency of the refrigerator compartment 4 is improved to save energy. Can be realized.
[0128]
In addition, since the refrigerant can be used efficiently, the amount of refrigerant can be reduced. In particular, when a flammable natural refrigerant (isobutane, propane, etc.) is used, the safety at the time of refrigerant leakage can be improved by reducing the amount of refrigerant. It becomes possible.
[0129]
(Embodiment 8)
FIG. 15 is a schematic diagram of a cooling cycle of a refrigerator according to another embodiment of the present invention.
[0130]
Reference numeral 25 denotes a low-pressure vessel type compressor.
[0131]
A flammable natural refrigerant (isobutane, propane, etc.) (not shown) is used as the refrigerant in the cooling cycle.
[0132]
By eliminating the shortage of refrigerant circulation during cooling of the refrigerator compartment 4, the amount of refrigerant can be reduced by improving the cooling efficiency of the refrigerator compartment 4, especially when combustible natural refrigerants (isobutane, propane, etc.) are used. By reducing the amount of refrigerant, it becomes possible to improve the safety at the time of refrigerant leakage.
[0133]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a refrigerator capable of saving energy by reducing the amount of refrigerant and improving the efficiency of a cooling system that switches between cooling of a refrigerator compartment and a freezer compartment.
[0134]
Moreover, since the refrigerant can be used efficiently from the above results, the amount of the refrigerant can be reduced. Especially when a flammable natural refrigerant (isobutane, propane, etc.) is used, the refrigerant amount is reduced, so that the safety at the time of refrigerant leakage is reduced. It is possible to provide a refrigerator capable of enhancing the performance.
[Brief description of the drawings]
FIG. 1 is a cooling cycle diagram of a refrigerator according to an embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view of flow path control means according to the same embodiment
FIG. 3 is a characteristic diagram of refrigerant filling amount of the first evaporator according to the same embodiment;
FIG. 4 is a refrigerant filling amount characteristic diagram of the second evaporator according to the same embodiment;
FIG. 5 is an operation time chart of the refrigerator according to the embodiment.
FIG. 6 is a front view of first and second evaporators according to another embodiment of the present invention.
FIG. 7 is a cooling cycle diagram of a refrigerator according to another embodiment of the present invention.
FIG. 8 is an operation time chart of the refrigerator according to the embodiment.
FIG. 9 is a cooling cycle diagram of a refrigerator according to another embodiment of the present invention.
FIG. 10 is an operation time chart of the refrigerator according to the embodiment.
FIG. 11 is a cooling cycle diagram of a refrigerator according to another embodiment of the present invention.
FIG. 12 is an operation time chart of the refrigerator according to the embodiment.
FIG. 13 is an operation time chart of a refrigerator according to another embodiment of the present invention.
FIG. 14 is an operation time chart of a refrigerator according to another embodiment of the present invention.
FIG. 15 is a cooling cycle diagram of a refrigerator according to another embodiment of the present invention.
FIG. 16 is a cooling cycle diagram of a conventional refrigerator.
[Explanation of symbols]
1 Compressor
2 Condenser
3 First evaporator
4 Cold room
5 Second evaporator
6 Freezer room
7 First decompression means
8 Second decompression means
9 Check valve
10 First on-off valve
11 Second on-off valve
12 Channel control means
13 First blowing means
14 Second blowing means
15 Refrigerator box
16 Machine room
17 First position
18 Second position
19 Third position
20 Rotating shaft
21 Seal member
22 cylinders
23 Variable capacity compressor
24 Defrost heater
25 Low pressure container type compressor

Claims

Compressor, condenser, flow path control means, first decompression means, first evaporator disposed in the refrigerator compartment, first blower means, second decompression means, refrigeration A second evaporator disposed in the room; a second blowing means; and a check valve; the compressor, the condenser, the flow path control means, the first pressure reducing means, and the first A refrigerating room side cooling circuit is formed with one evaporator, and the second pressure reducing means, the second evaporator, and the second pressure reducing means are arranged in parallel with the first pressure reducing means and the first evaporator. A check valve is connected, and a freezer compartment side cooling circuit is formed by the compressor, the condenser, the flow path control means, the second pressure reducing means, the second evaporator, and the check valve. The cooling chamber and the freezing chamber are independently cooled by switching the flow of refrigerant to each cooling circuit by the flow path control means. Ri, by volume of the pipe constituting the first evaporator and capacity as compared to a small volume in the pipe constituting the second evaporator, the refrigerating chamber cooling for cooling the refrigerating compartment small comb compared required refrigerant amount of the freezing chamber side cooling circuit for required amount of refrigerant circuit cools the freezer compartment, the compressor is a variable capacity type, when starting the cooling of the refrigerating compartment, By operating the compressor at a rotational speed higher than the normal rotational speed for a predetermined time, a part of the refrigerant staying in the second evaporator when switching from cooling of the freezer compartment to cooling of the refrigerator compartment is performed. Is circulated through the first evaporator to secure a necessary amount of refrigerant for cooling the refrigerator compartment .

2. The refrigerator according to claim 1 , wherein the amount of decompression by the first decompression means is 0.2 MPa or more and 0.5 MPa or less.

Periodically defrosting heater provided defrosted second evaporator, when starting the cooling of the refrigerating compartment, to claim 1 or 2, characterized in that energizing the between defrosting heater for a predetermined time The refrigerator described.

The defrosting heater which performs defrosting of a 2nd evaporator regularly is provided, and when starting cooling of a refrigerator compartment, it supplies electricity to a defrosting heater intermittently for a predetermined period of time. The refrigerator according to any one of claims 3 to 4.

When starting the cooling of the refrigerating compartment, the refrigerator according to any one of claims 1 to 4, characterized in that operating the second blowing means during the predetermined time.

The refrigerator according to any one of claims 1 to 5 , wherein the compressor is a low-pressure container type, and a combustible natural refrigerant is used as a refrigerant in a cooling cycle.