JP3807755B2

JP3807755B2 - Multi-room air conditioner

Info

Publication number: JP3807755B2
Application number: JP00648095A
Authority: JP
Inventors: 利彰吉川; 浩招牧野; 英行尾形; 基夫佐野; 威倉持; 広征小田木; 奈津子今城
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 1995-01-19
Filing date: 1995-01-19
Publication date: 2006-08-09
Anticipated expiration: 2021-08-09
Also published as: JPH08193763A

Description

【０００１】
【産業上の利用分野】
この発明は、一台の室外機で複数台の室内機を運転して、冷房運転及び暖房運転ができるマルチタイプの空気調和機に関するものである。
【０００２】
【従来の技術】
（従来例１）
図１４は従来のマルチタイプの空気調和機の冷媒回路図で、１は冷媒を圧縮する圧縮機、２は該圧縮機１の接続されて、冷媒の流れを冷房または暖房のサイクルに切り換える四方弁、３は一方が該四方弁２に接続された室外熱交換器、４ａ〜４ｃは主回路から並列分岐された複数の電子膨張弁、５ａ〜５ｃは一方が該電子膨張弁４ａ〜４ｃに接続され、他方が主回路の四方弁２に接続された室内熱交換器、６は四方弁２と圧縮機１の間に設けられたアキュムレータ、７は蒸発温度を測定するために設けられた蒸発温度生成回路の毛細管である。そして、圧縮機１の吐出管とアキュムレータ６の入口管の間に毛細管８、１０とそれらに挟まれた電磁弁９からなるバイパス回路が形成されている。
【０００３】
次に動作を説明する。図１４に示す従来のマルチタイプの空気調和機では、圧縮機１の運転停止時には、バイパス回路の電磁弁９を開くと共に、電子膨張弁４ａ〜４ｃを最大開度まで開けることによって、冷媒を急速に移動させ、高低圧をより早くバランスさせて冷媒回路内の圧力を均一にして、次回の起動を容易にしている。
しかし、バイパス回路をアキュムレータ６の入口側に接続しているので、圧縮機１の停止時に電磁弁９を開くと、高圧の冷媒がバイパス回路を流れ、アキュムレータ６に溜まっている冷媒液が圧縮機１に押し出されて圧縮機１に冷媒液が溜る。
さらに、圧縮機１の停止時に電子膨張弁４ａ〜４ｃを最大開度まで開くと、冷房運転時蒸発器として動作する室内熱交換器５ａ〜５ｃ内の冷媒が急速にアキュムレータ６に移動して、アキュムレータ６が溢れて圧縮機１に冷媒が溜まる。
【０００４】
（従来例２）
図１５は他の従来のマルチタイプの空気調和機を示す冷媒回路図であり、符号１〜３、４ａ〜４ｃ、５ａ〜５ｃは従来例１と同様であるのでその説明は省略する。１３ａ〜１３ｃは室内熱交換器５ａ〜５ｃの反電子膨張弁側に設けられた二方弁、１４は圧縮機１の吸入管に設けられ、吸入冷媒温度を検出する吸入冷媒温度センサ、１５ａ〜１５ｃは冷房運転用の蒸発温度センサ、１８は暖房運転用の蒸発温度センサ、２０はマルチコントローラで、電子膨張弁４ａ〜４ｃ、二方弁１３ａ〜１３ｃはこのマルチコントローラ２０の部分に配設されている。
【０００５】
次に動作について説明する。吸入冷媒温度センサ１４と蒸発温度センサ１５ａ〜１５ｃ、１８の各検知信号はマルチコントローラ１０の演算部に送られ、マルチコントローラ１０で圧縮機１の吸入冷媒温度と蒸発器の蒸発温度の差から、冷房時及び暖房時における吸入ガスの過熱度が検出され、その結果に基づいて電子膨張弁４ａ〜４ｃの開度を決定して過熱度制御を行なう。
特に冷房運転の場合、室内熱交換器５ａ〜５ｃが蒸発器として動作するが、室内熱交換器５ａ〜５ｃの出口付近では冷媒の温度がそれぞれの回路で異なるが上記過熱度制御ではこの部分の制御が行なわれていない。
【０００６】
【発明が解決しようとする課題】
従来のマルチタイプの空気調和機は以上のように構成されているので、次のような問題点があった。
１．従来例１の課題
（１）圧縮機１停止時に、バイパス回路が開放されてアキュムレータ６の冷媒液が圧縮機１に溜まり、この状態で再起動すると圧縮機１内の潤滑油が外部に持ち出され潤滑油が不足するために圧縮機１の寿命が低下する。
（２）また、圧縮機１停止時に、電子膨張弁４が最大に開かれるので、蒸発器内の冷媒が急速にアキュムレータ６に移動し、アキュムレータ６から冷媒が溢れて圧縮機１に冷媒が溜まると同時に、急速な冷媒の移動による冷媒音が騒音となる。
（３）圧縮機１の吐出側と吸入側の圧力差が十分小さくなってから再起動するので、再起動後安定状態になるまでの所要時間が長かった。
２．従来例２の課題
（１）過熱度制御は、冷房運転時室内熱交換器５ａ〜５ｃの入口側と圧縮機１の吸入管の温度で行なっているため、室内熱交換器５ａ〜５ｃ（蒸発器）の冷媒温度は各分岐回路で異なり、延長配管を用いる場合とか、室内負荷が変動した場合は、合流後の圧縮機１の吸入管の過熱度は適正であっても個々の分岐回路の合流前の冷媒の過熱度が付き過ぎるものも出てきて、その場合には室内熱交換器の温度分布が一様でなく温度勾配が発生し、吹出空気の温度もバラツクため、露飛び或は能力低下等の問題が発生しやすい。
【０００７】
この発明は以上のような問題点を解決するためになされたもので、その目的とするところは次の通りである。
（１）圧縮機の停止時に圧縮機に冷媒液が溜らないようにし、起動時の潤滑油不足を防止して、圧縮機の長寿命化を目指す。
（２）圧縮機停止時の冷媒の移動により発生する冷媒音を防止する。
（３）圧縮機停止時に室外熱交換器から液冷媒が蒸発温度生成回路を通ってアキュムレータに流入し、溢れるのを防止する。
（４）室内熱交換器の温度分布ムラによる露飛び、能力低下を防止する。
【０００８】
【課題を解決するための手段】
請求項１の多室形空気調和機は、圧縮機、四方弁、室外熱交換器、主回路から並列分岐された分岐配管間夫々に冷媒の流量を調整する電子膨張弁、アキュムレータを順次接続して冷媒回路を構成し、室外熱交換器と電子膨張弁との間に一端が接続され他端がアキュムレータの入口側に接続された蒸発温度生成回路を設けた、冷暖房切り換え可能な室外機と、電子膨張弁夫々に室内熱交換器を接続した室内機とを有する多室形空気調和機において、蒸発温度生成回路は蒸発温度生成用電子膨張弁を有し、圧縮機と四方弁の間と圧縮機とアキュムレータの間に設けられ、圧縮機の運転中は閉じた電磁弁と毛細管とを有するバイパス回路と、圧縮機の停止時に、電子膨張弁を最小開度まで閉じる又は電子膨張弁を閉じ、室外熱交換器からアキュムレータに液冷媒が流れ込むのを抑制するために蒸発温度生成用電子膨張弁を最小開度まで閉じ、更にバイパス回路の電磁弁を開く制御手段とを備えたことを特徴とする。
【０００９】
請求項２の多室形空気調和機は、圧縮機、四方弁、室外熱交換器、主回路から並列分岐された分岐配管間夫々に冷媒の流量を調整する電子膨張弁、アキュムレータを順次接続して冷媒回路を構成し、室外熱交換器と電子膨張弁との間に一端が接続され他端がアキュムレータの入口側に接続された蒸発温度生成回路を設けた、冷暖房切り換え可能な室外機と、電子膨張弁夫々に室内熱交換器を接続した室内機とを有する多室形空気調和機において、蒸発温度生成回路は蒸発温度生成用電子膨張弁を有し、圧縮機と四方弁の間と圧縮機とアキュムレータの間に設けられ、圧縮機の運転中は閉じた電磁弁と毛細管とを有するバイパス回路と、圧縮機の停止時に、電子膨張弁を最小開度まで閉じる又は電子膨張弁を閉じ、室外熱交換器からアキュムレータに液冷媒が流れ込むのを抑制するために蒸発温度生成用電子膨張弁を閉じ、更にバイパス回路の電磁弁を開く制御手段とを備えたことを特徴とする。
【００１０】
請求項３の多室形空気調和機は、請求項２記載のもので、制御手段はバイパス回路の電磁弁が開き高低圧が平衡した後に電子膨張弁を所定開度に開くことを特徴とする。
【００１１】
【作用】
請求項１の多室形空気調和機は、蒸発温度生成用電子膨張弁を最小開度まで閉じることにより室外熱交換器から蒸発温度生成回路を通ってアキュムレータへ移動する液冷媒が略なくなる。
【００１２】
請求項２の多室形空気調和機は、蒸発温度生成用電子膨張弁を閉じることにより室外熱交換器から蒸発温度生成回路を通ってアキュムレータへ移動する液冷媒がなくなる。
【００１３】
請求項３の多室形空気調和機は、高低圧平衡後に蒸発温度生成用電子膨張弁を所定開度に開くので、長期間使用されない場合蒸発温度生成用電子膨張弁が閉じたままの状態にならない。
【００１４】
【実施例】
参考例１．
（参考例１の概要）
空気調和機は運転を止めた停止中、一般に次の起動に備えて電子膨張弁を開いて高低圧を平衡させる。しかし、再起動後の冷房（暖房）運転の立上がりを早くするには停止時に電子膨張弁をむしろ閉じるか最小開度にして、凝縮器や蒸発器の冷媒を移動させない方が良い。その場合高低圧はバランスしないので、再起動時圧縮機は起動しにくいが、例えばスクロール式圧縮機のように差圧起動可能なものにすれば、高低圧がバランスしていない場合でも起動可能になる。但し、真夏の厳しい状態では、高低圧差が大きく、差圧起動の可能な圧縮機といえども起動できない場合がある。その為高低圧をバランスさせるためのバスパイ回路を設けるが、従来のようにアキュムレータの上流側にバイパス回路を接続すると、アキュムレータ内の液冷媒が圧縮機に押し出されて圧縮機に溜り様々な悪影響を与える。そこでこの実施例ではバイパス回路をアキュムレータの後流側に接続して、バイパス回路が動作して高低圧がバランスする際にアキュムレータ内の液冷媒が圧縮機へ押し出されるのを防止するものである。
【００１５】
以下、この発明の参考例１について説明する。図１はこの発明の参考例１による空気調和機の冷媒回路図であり、図において、符号１〜７は従来の装置と全く同一のものでありその説明は省略する。１２は液化した高圧冷媒がガス管側冷媒と熱交換してサブクールを大きくとるための二重管熱交換器である。従来の装置と異なる重要なポイントは、毛細管８、１０と電磁弁９で構成されたバイパス回路がアキュムレータ６の出口側に接続されていることである。
そして、圧縮機１、四方弁２、電子膨張弁４ａ〜４ｃ、電磁弁９は図２に示すように、制御基板２０（マイコン）からの信号によって制御されている。
【００１６】
次に動作について説明する。圧縮機１の運転中は、バイパス回路の電磁弁９は閉じており、バイパス回路は動作しない。図３のフローチャートにおいて、ステップ３０でスイッチがオフされると、圧縮機１が停止し（ステップ３１）、続いて、ステップ３２で電子膨張弁４ａ〜４ｃを最小開度まで閉じて各熱交換器の冷媒が移動しないようにする。そして、再起動を容易にする目的でバイパス回路の電磁弁９を開いて高圧冷媒ガスを圧縮機１の吸入側に流して圧縮機１の吐出側と吸入側をバランスさせる（ステップ３３）。この時バイパス回路を通過した冷媒はアキュムレータ６を通らないので、アキュムレータ６内の冷媒液が圧縮機１に流れこむことがない。
このように、この参考例では起動後の運転の立上りを早くするために、圧縮機１の停止時に電子膨張弁４ａ〜４ｃを最小開度まで閉じるので、本来は差圧起動可能な例えばスクロール式圧縮機が適するが、起動を確実にするために、バイパス回路によって高低圧のバランスを強制的に行うので、差圧起動に向かない例えばロータリー圧縮機も使用可能になる。
また、圧縮機１停止時に、電子膨張弁４ａ〜４ｃを全閉にしないで、最小開度にするのは、空気調和機が使用されないで、長時間全閉の状態が続くと機械的に動作不良になることがあるためである。
【００１７】
この参考例によれば、圧縮機１停止時に、電子膨張弁４ａ〜４ｃを最小開度まで閉じるもので、起動を容易にするために設けられた、高低圧をバランスさせるバイパス回路を圧縮機１の吐出側からアキュムレータ６の出口側に接続したので、バイパス回路動作時にアキュムレータ６内の液冷媒を圧縮機１に押し出すことがなく、圧縮機１の再起動時の潤滑油不足を防止することができる。
【００１８】
参考例２．
（参考例２の概要）
参考例１では、圧縮機の停止時に主回路の電子膨張弁を最小開度まで閉じるようにしたが、蒸発器（室内熱交換器）での冷媒の移動が多少あるため冷媒音の問題が残る。そこで、この実施例では、圧縮機の停止時に主回路の電子膨張弁を閉じることにより、蒸発器の冷媒音を無くしたものである。
【００１９】
以下、この発明の参考例２を図について説明する。冷媒回路の構成は、実施例１と全く同一であるので、その説明は省略する。
【００２０】
次に動作を図４のフローチャートに従って説明する。ステップ４０でスイッチがオフされると、ステップ４１で圧縮機１が停止し、続いてステップ４２で各熱交換器内の冷媒の移動を防止するために、電子膨張弁４ａ〜４ｃを完全に閉じる。電子膨張弁４ａ〜４ｃを閉じることによって蒸発器（室内熱交換器）で冷媒が移動しないため冷媒音が発生しない。そして、ステップ４３で高低圧をバランスさせて再起動を容易にするためにバイパス回路の電磁弁９を開く。これらは、参考例１と同様である。
【００２１】
この参考例によれば、圧縮機１の停止時に電子膨張弁４ａ〜４ｃを完全に閉じ、さらに圧縮機１の吐出側からアキュムレータ６の出口側に接続されたバイパス回路の電磁弁９を開くようにしたので、実施例１と同様の効果を奏すると共に、圧縮機１の停止時における蒸発器（室内熱交換器５ａ〜５ｃ）での冷媒音を防止できる。
【００２２】
参考例３．
なお、参考例２では圧縮機１の停止時に電子膨張弁４ａ〜４ｃを完全に閉じるものを示したが、長期間空気調和機を使用しない場合に、電子膨張弁４ａ〜４ｃが閉じたままとなり機械的な原因による動作不良を起こすことがあるので、圧縮機１の停止時に電子膨張弁４ａ〜４ｃを閉じ、次に、電磁弁９を開いて高低圧がバランスしたら電子膨張弁４ａ〜４ｃを所定開度に開くようにしても良い。この場合のフローチャートを図５に示す。図４のフローチャートに電子膨張弁４ａ〜４ｃを所定開度に開くステップ４４を追加したものである。
【００２３】
実施例１．
（実施例１の概要）
参考例１、２では、蒸発温度生成回路に毛細管を用いたものを示したが、マルチタイプの空気調和機の場合、例えば使用されない室内ユニットがあると余った冷媒がアキュムレータに溜り液面レベルが上り、蒸発温度生成回路を通して圧縮機停止時に室外熱交換器からアキュムレータに流れ込む液冷媒の影響が無視できなくなる。この実施例はそれを防止するため蒸発温度生成回路の毛細管の代わりに電子膨張弁を使用し、圧縮機停止時の蒸発温度生成回路を通して室外熱交換器からアキュムレータに液冷媒が流れ込むのを防止する。
【００２４】
以下、この発明の実施例１を図について説明する。図６はこの発明の実施例４による空気調和機の冷媒回路図である。図において、符号１１以外は参考例１の図１と全く同一のものであり、その説明は省略する。１１は室外熱交換器３と電子膨張弁４ａ〜４ｃの間に一端が接続され他端がアキュムレータの入口側に接続された蒸発温度生成回路に設けられた電子膨張弁である。
【００２５】
次に動作を図７のフローチャートに従って説明する。ステップ５０でスイッチがオフされると、ステップ５１で圧縮機１が停止し、続いて参考例１または参考例２と同様の目的でステップ５２で電子膨張弁４ａ〜４ｃを最小開度まで閉じるか、または閉じる。さらに、ステップ５３で電子膨張弁１１を最小開度まで閉じることにより、室内熱交換器３から蒸発温度生成回路を通ってアキュムレータ６に液冷媒が流れ込むのを極力抑えアキュムレータ６から液冷媒が溢れ出るのを防止する。そしてステップ５４でバイパス回路の電磁弁９を開いて高低圧をバランスさせる。
電子膨張弁１１を全閉にしないのは、参考例１の電子膨張弁４ａ〜４ｃのケースと同じ理由による。
【００２６】
この実施例によれば、圧縮機１の停止時に、電子膨張弁４ａ〜４ｃを最小開度まで閉じるか、または閉じて各熱交換器の冷媒の移動を抑制し、かつ蒸発温度生成回路の電子膨張弁１１を最小開度まで閉じるようにしたので、使用されない室内ユニットがあってアキュムレータ６の液面レベルが高くなる場合でも、アキュムレータ６から冷媒液が溢れ出るのを抑制する。
【００２７】
実施例２．
なお、実施例１では、電子膨張弁１１を最小開度まで閉じるものを示したが、これを完全に閉じても良い。図８にその場合のフローチャートを示す。このようにすれば、圧縮機１の停止時室外熱交換器３から蒸発温度生成回路を通ってアキュムレータ６へ流れ込む液冷媒を無くすことができる。
【００２８】
実施例３．
また、実施例２でバイパス回路の電磁弁９を開いた後、図９のフローチャートに示すように、ステップ６５で高低圧バランス後電子膨張弁１１を所定開度に開けておくことにより長期間空気調和機を使用しない場合の、電子膨張弁１１の機械的な動作不良を防止することができる。
【００２９】
参考例４．
（参考例４の概要）
この参考例は、各室内ユニットのガス配管側に温度センサを設けて各ガス管温度を検出し、蒸発温度センサによる蒸発温度と比較することにより各室内出口ＳＨ（過熱度）を求め、この中の最小値を基準値にしてその他の室内出口ＳＨの前記基準値との公差を求める。そしてその各室内出口ＳＨ公差が、吸入ＳＨ及び吐出温度も含めて目標範囲に入るまで各室内ユニットの電子膨張弁の補正を繰返す。このようにして、室内負荷変動・延長配管の差異がある場合でも、各室内ユニット出口ＳＨを一定範囲に納め、室内ユニットで発生する露飛び、能力低下等の発生を防止するものである。
【００３０】
以下、この発明の参考例４を図について説明する。図１０はこの発明の参考例４による空気調和機の冷媒回路図である。図において、符号１〜７、１４は従来の装置と全く同一のものでありその説明は省略する。１５は室外熱交換器３と電子膨張弁４ａ〜４ｃの間から分岐して圧縮機１の吸入側へ接続され、毛細管７が設けられた蒸発温度生成回路の蒸発温度を検出する蒸発温度センサ、１６ａ〜１６ｃは各室内熱交換器５ａ〜５ｃの出口温度を検出するガス管温度センサ、２１は圧縮機１の吐出温度を検出する吐出温度センサ、３０は電子膨張弁制御用のコントローラである。
【００３１】
次に動作について説明する。
吸入冷媒温度センサ１４、蒸発温度センサ１５、ガス管温度センサ１６ａ〜１６ｃ及び吐出温度センサ２１の出力値を電子膨張弁制御用のコントローラ３０に入力し、以下に述べる手順により各電子膨張弁４ａ〜４ｃの弁開度制御を行う。弁開度制御の内容について説明するが、その説明に用いる吸入ＳＨ、各室内出口ＳＨ（ａ，ｂ，ｃ）、各室内出口ＳＨ公差（ａ，ｂ，ｃ）の算出式を（１）〜（３）式で定義しておく。
【００３２】
【数１】

【００３３】
図１１のフローチャートにより弁開度制御の内容を説明する。ステップ１００で室内ユニットの運転がスタートし、次にステップ１０１でコントローラ３０が電子膨張弁４ａ〜４ｃの開度と圧縮機１の運転周波数の初期値を設定する。この場合電子膨張弁４ａ〜４ｃの開度は室内ユニットの能力にて開度比率が変更される。ステップ１０２で（１）式で定義される吸入ＳＨが目標値の範囲に入っているかチェックし、ステップ１０３にて電子膨張弁４ａ〜４ｃの開度補正を図１３（ａ）に従ってそれぞれ均一に行う。次にステップ１０４で吐出温度が目標値に範囲に入っているかチェックし、ステップ１０５で電子膨張弁４ａ〜４ｃの開度を図１３（ｂ）に従ってそれぞれ均一に補正する。ステップ１０５の過程終了后に（２）式で定義される各室内出口ＳＨ（ａ，ｂ，ｃ）及び（３）式で定義される各室内出口ＳＨ公差（ａ，ｂ，ｃ）を算出しステップ１０６ａで各室内出口ＳＨ公差（ａ，ｂ，ｃ）が目標範囲に入っているか判断する。もし目標範囲に入っていない場合は、ステップ１０７ａで電子膨張弁４ａ〜４ｃの最小値以外のものの開度を図１３（ｃ）に従って補正する。目標範囲に入っている場合は、ステップ１０８で吸入ＳＨ及び吐出温度が目標値に入っているか判断し、目標値に入っていればステップ１０９で電子膨張弁４ａ〜４ｃの開度を固定する。そして目標値に入っていなければステップ１０２に戻り、吸入ＳＨ、吐出温度、室内出口ＳＨ公差の全てが目標値に入るまで上記過程を繰り返す。
【００３４】
室内出口ＳＨの最小値を基準値として、その他の室内ユニットの出口ＳＨをこれに近づける制御を行なう故であるが、室内出口ＳＨの最小値は圧縮機１の吸入温度の過熱度（吸入ＳＨ）と圧縮機１の吐出温度を制御することにより所望の範囲に入るので、その最小値との公差が目標範囲に入れば各室内出口ＳＨは適正な値になり、各室内熱交換器の温度分布にムラが無く、露飛び、能力ダウンを防止することができる。
【００３５】
参考例５．
参考例４では、室内出口ＳＨ公差を利用して、電子膨張弁４ａ〜４ｃの補正を行ったが、室内出口ＳＨ公差の代わりにガス管温度公差を用いても良い。
冷媒回路図は図１０と同じである。
制御の内容の説明に用いるガス管温度公差を（４）式で定義しておく。
【００３６】
【数２】

【００３７】
図１２のフローチャートに基づいて弁開度制御の内容を説明する。ステップ１０６ｂ、１０７ｂ以外は図１１のフローチャートと全く同じであり、ステップ１０６ｂで（４）式で定義される各ガス管温度（ａ，ｂ，ｃ）が目標範囲に入っているか判断し、もし目標範囲に入っていない場合はステップ１０７ｂで最小値となるものを除く電子膨張弁（４ａ，４ｂ，４ｃ）の開度を図１３（ｄ）に従って補正する。各ガス管温度（ａ，ｂ，ｃ）が目標範囲に入っていない場合は、ステップ８に行く。その他の過程は図１１と同じであるのでその説明は省略する。
【００３８】
室内出口ＳＨ公差の代りにガス管温公差を利用するこの参考例の基本的な作用効果、即ち室内熱交換器の温度分布を均一にして露飛び、能力ダウンを防止するという点は参考例４と同じであるが、参考例５では室内出口ＳＨの代りにガス管温度公差を利用するので、ガス管温度センサ（１６ａ〜１６ｃ）の検出温度と蒸発温度センサ１５の検出温度の比較をする必要がなく、計算処理が簡単になるという効果を奏する。
【００３９】
【発明の効果】
請求項１の多室形空気調和機は、圧縮機、四方弁、室外熱交換器、主回路から並列分岐された分岐配管間夫々に冷媒の流量を調整する電子膨張弁、アキュムレータを順次接続して冷媒回路を構成し、室外熱交換器と電子膨張弁との間に一端が接続され他端がアキュムレータの入口側に接続された蒸発温度生成回路を設けた、冷暖房切り換え可能な室外機と、電子膨張弁夫々に室内熱交換器を接続した室内機とを有する多室形空気調和機において、蒸発温度生成回路は蒸発温度生成用電子膨張弁を有し、圧縮機と四方弁の間と圧縮機とアキュムレータの間に設けられ、圧縮機の運転中は閉じた電磁弁と毛細管とを有するバイパス回路と、圧縮機の停止時に、電子膨張弁を最小開度まで閉じる又は電子膨張弁を閉じ、室外熱交換器からアキュムレータに液冷媒が流れ込むのを抑制するために蒸発温度生成用電子膨張弁を最小開度まで閉じ、更にバイパス回路の電磁弁を開く制御手段とを備えた構成にしたので、余剰冷媒がアキュムレータに溜っている場合でもアキュムレータから冷媒液が溢れ出る恐れがなく、圧縮機の潤滑性能低下を防止できる。
【００４０】
請求項２の多室形空気調和機は、圧縮機、四方弁、室外熱交換器、主回路から並列分岐された分岐配管間夫々に冷媒の流量を調整する電子膨張弁、アキュムレータを順次接続して冷媒回路を構成し、室外熱交換器と電子膨張弁との間に一端が接続され他端がアキュムレータの入口側に接続された蒸発温度生成回路を設けた、冷暖房切り換え可能な室外機と、電子膨張弁夫々に室内熱交換器を接続した室内機とを有する多室形空気調和機において、蒸発温度生成回路は蒸発温度生成用電子膨張弁を有し、圧縮機と四方弁の間と圧縮機とアキュムレータの間に設けられ、圧縮機の運転中は閉じた電磁弁と毛細管とを有するバイパス回路と、圧縮機の停止時に、電子膨張弁を最小開度まで閉じる又は電子膨張弁を閉じ、室外熱交換器からアキュムレータに液冷媒が流れ込むのを抑制するために蒸発温度生成用電子膨張弁を閉じ、更にバイパス回路の電磁弁を開く制御手段とを備えた構成にしたので、余剰冷媒がアキュムレータに溜っている場合でもアキュムレータから冷媒液が溢れ出ることがなく、圧縮機の潤滑性能低下を防止できる。
【００４１】
請求項３の多室形空気調和機は、請求項２記載のもので、制御手段はバイパス回路の電磁弁を開き高低圧が平衡した後に蒸発温度生成用電子膨張弁を所定開度に開く構成にしたので、長期間空気調和機を使用しない場合の蒸発温度生成用電子膨張弁の機械的な動作不良を無くすことができる。
【図面の簡単な説明】
【図１】この発明の参考例１による多室形空気調和機の冷媒回路図である。
【図２】この発明の参考例１による多室形空気調和機の制御ブロック図である。
【図３】この発明の参考例１による多室形空気調和機の制御内容を示すフローチャート図である。
【図４】この発明の参考例２による多室形空気調和機の制御内容を示すフローチャート図である。
【図５】この発明の参考例３による多室形空気調和機の制御内容を示すフローチャート図である。
【図６】この発明の実施例１による多室形空気調和機の冷媒回路図である。
【図７】この発明の実施例１による多室形空気調和機の制御内容を示すフローチャート図である。
【図８】この発明の実施例２による多室形空気調和機の制御内容を示すフローチャート図である。
【図９】この発明の実施例３による多室形空気調和機の制御内容を示すフローチャート図である。
【図１０】この発明の参考例４による多室形空気調和機の冷媒回路図である。
【図１１】この発明の参考例４による多室形空気調和機の制御内容を示すフローチャート図である。
【図１２】この発明の参考例５による多室形空気調和機の制御内容を示すフローチャート図である。
【図１３】この発明の参考例４、５による多室形空気調和機の制御の具体的動作を示す図である。
【図１４】従来の多室形空気調和機（従来例１）の冷媒回路図である。
【図１５】従来の多室形空気調和機（従来例２）の冷媒回路図である。
【符号の説明】
１圧縮機、２四方弁、３室外熱交換器、４ａ〜４ｃ電子膨張弁、５ａ〜５ｃ室内熱交換器、６アキュムレータ、９電磁弁、１１蒸発温度生成用電子膨張弁、１４吸入温度センサ、１５蒸発温度センサ、１６ａ〜１６ｃガス管温度センサ、２１吐出温度センサ。[0001]
[Industrial application fields]
The present invention relates to a multi-type air conditioner that can perform a cooling operation and a heating operation by operating a plurality of indoor units with one outdoor unit.
[0002]
[Prior art]
(Conventional example 1)
FIG. 14 is a refrigerant circuit diagram of a conventional multi-type air conditioner, in which 1 is a compressor that compresses refrigerant, 2 is a four-way valve that is connected to the compressor 1 and switches the refrigerant flow to a cooling or heating cycle. 3 is an outdoor heat exchanger, one of which is connected to the four-

way valve

2, 4a to 4c are a plurality of electronic expansion valves branched in parallel from the main circuit, and 5a to 5c are connected to the electronic expansion valves 4a to 4c. And the other is an indoor heat exchanger connected to the four-way valve 2 of the main circuit, 6 is an accumulator provided between the four-way valve 2 and the compressor 1, and 7 is an evaporation temperature provided for measuring the evaporation temperature. It is a capillary of the generation circuit. A bypass circuit is formed between the discharge pipe of the compressor 1 and the inlet pipe of the accumulator 6 and includes the

capillary tubes

8 and 10 and the electromagnetic valve 9 sandwiched between them.
[0003]
Next, the operation will be described. In the conventional multi-type air conditioner shown in FIG. 14, when the operation of the compressor 1 is stopped, the solenoid valve 9 of the bypass circuit is opened, and the electronic expansion valves 4a to 4c are opened to the maximum opening, whereby the refrigerant is rapidly discharged. To make the pressure in the refrigerant circuit uniform by balancing the high and low pressures more quickly, thereby facilitating the next start-up.
However, since the bypass circuit is connected to the inlet side of the accumulator 6, when the electromagnetic valve 9 is opened when the compressor 1 is stopped, the high-pressure refrigerant flows through the bypass circuit, and the refrigerant liquid accumulated in the accumulator 6 is discharged from the compressor. The refrigerant liquid is accumulated in the compressor 1 by being pushed out by 1.
Further, when the electronic expansion valves 4a to 4c are opened to the maximum opening degree when the compressor 1 is stopped, the refrigerant in the indoor heat exchangers 5a to 5c operating as an evaporator during cooling operation rapidly moves to the accumulator 6, The accumulator 6 overflows and the refrigerant accumulates in the compressor 1.
[0004]
(Conventional example 2)
FIG. 15 is a refrigerant circuit diagram showing another conventional multi-type air conditioner, and reference numerals 1 to 3, 4 a to 4 c, and 5 a to 5 c are the same as those in the first conventional example, and the description thereof is omitted. Reference numerals 13a to 13c denote two-way valves provided on the side opposite to the electronic expansion valves of the indoor heat exchangers 5a to 5c, reference numeral 14 denotes an intake refrigerant temperature sensor provided on the intake pipe of the compressor 1 for detecting the intake refrigerant temperature, and 15a to 15c. 15c is an evaporating temperature sensor for cooling operation, 18 is an evaporating temperature sensor for heating operation, 20 is a multi-controller, and the electronic expansion valves 4a to 4c and the two-way valves 13a to 13c are arranged in the multi-controller 20 part. ing.
[0005]
Next, the operation will be described. The detection signals of the suction refrigerant temperature sensor 14 and the evaporation temperature sensors 15a to 15c, 18 are sent to the calculation unit of the multi-controller 10, where the multi-controller 10 determines the difference between the suction refrigerant temperature of the compressor 1 and the evaporation temperature of the evaporator. The degree of superheat of the intake gas during cooling and heating is detected, and based on the result, the opening degree of the electronic expansion valves 4a to 4c is determined to perform superheat degree control.
Especially in the case of cooling operation, the indoor heat exchangers 5a to 5c operate as evaporators, but the refrigerant temperatures differ in the respective circuits near the outlets of the indoor heat exchangers 5a to 5c, but in the superheat control, this portion There is no control.
[0006]
[Problems to be solved by the invention]
Since the conventional multi-type air conditioner is configured as described above, it has the following problems.
1. Problems of Conventional Example 1
(1) When the compressor 1 is stopped, the bypass circuit is opened and the refrigerant liquid in the accumulator 6 is accumulated in the compressor 1, and when restarted in this state, the lubricating oil in the compressor 1 is taken out and the lubricating oil becomes insufficient. For this reason, the life of the compressor 1 is reduced.
(2) Since the electronic expansion valve 4 is opened to the maximum when the compressor 1 is stopped, the refrigerant in the evaporator rapidly moves to the accumulator 6, and the refrigerant overflows from the accumulator 6 and accumulates in the compressor 1. At the same time, the refrigerant noise caused by the rapid movement of the refrigerant becomes noise.
(3) Since the restart is performed after the pressure difference between the discharge side and the suction side of the compressor 1 becomes sufficiently small, it takes a long time to reach a stable state after the restart.
2. Problems of Conventional Example 2
(1) Since the superheat control is performed at the temperatures of the inlet side of the indoor heat exchangers 5a to 5c and the suction pipe of the compressor 1 during the cooling operation, the refrigerant temperature of the indoor heat exchangers 5a to 5c (evaporator) Is different in each branch circuit, and when the extension pipe is used or the indoor load fluctuates, even if the superheat degree of the suction pipe of the compressor 1 after merging is appropriate, the refrigerant before merging in the individual branch circuits Some of them are too superheated. In that case, the temperature distribution of the indoor heat exchanger is not uniform and a temperature gradient occurs, and the temperature of the blown air varies, causing problems such as dewdrops or reduced capacity. Is likely to occur.
[0007]
The present invention has been made to solve the above-described problems, and its object is as follows.
(1) The refrigerant liquid is prevented from accumulating in the compressor when the compressor is stopped, and a shortage of lubricating oil at the start-up is prevented, thereby aiming to extend the life of the compressor.
(2) Refrigerant noise generated by refrigerant movement when the compressor is stopped is prevented.
(3) When the compressor is stopped, liquid refrigerant flows from the outdoor heat exchanger through the evaporation temperature generation circuit and flows into the accumulator and is prevented from overflowing.
(4) Prevent dew owing to uneven temperature distribution of the indoor heat exchanger and decrease in capacity.
[0008]
[Means for Solving the Problems]
The multi-room air conditioner according to claim 1 is a compressor, a four-way valve, an outdoor heat exchanger. An electronic expansion valve that adjusts the flow rate of refrigerant and an accumulator are connected in series between the branch pipes branched in parallel from the main circuit to form a refrigerant circuit, and one end is connected between the outdoor heat exchanger and the electronic expansion valve The other end is connected to the inlet side of the accumulator. In a multi-room air conditioner having an outdoor unit and an indoor unit in which an indoor heat exchanger is connected to each of the electronic expansion valves, the evaporation temperature generation circuit has an electronic expansion valve for generating the evaporation temperature, and the compressor and the four-way valve And a bypass circuit having a solenoid valve and a capillary tube closed during operation of the compressor and when the compressor is stopped, the electronic expansion valve is closed to the minimum opening or when the compressor is stopped. Control means for closing the valve, closing the electronic expansion valve for generating the evaporation temperature to the minimum opening degree, and further opening the electromagnetic valve of the bypass circuit in order to prevent the liquid refrigerant from flowing from the outdoor heat exchanger to the accumulator It is characterized by.
[0009]
The multi-room air conditioner according to claim 2 includes a compressor, a four-way valve, and an outdoor heat exchanger. An electronic expansion valve that adjusts the flow rate of refrigerant and an accumulator are connected in series between the branch pipes branched in parallel from the main circuit to form a refrigerant circuit, and one end is connected between the outdoor heat exchanger and the electronic expansion valve The other end is connected to the inlet side of the accumulator. In a multi-room air conditioner having an outdoor unit and an indoor unit in which an indoor heat exchanger is connected to each of the electronic expansion valves, the evaporation temperature generation circuit has an electronic expansion valve for generating the evaporation temperature, and the compressor and the four-way valve And a bypass circuit having a solenoid valve and a capillary tube closed during operation of the compressor and when the compressor is stopped, the electronic expansion valve is closed to the minimum opening or when the compressor is stopped. Control means for closing the valve, closing the evaporating temperature generating electronic expansion valve, and further opening the electromagnetic valve of the bypass circuit in order to prevent the liquid refrigerant from flowing into the accumulator from the outdoor heat exchanger. .
[0010]
The multi-chamber air conditioner according to claim 3 is the one according to claim 2, wherein the control means opens the electronic expansion valve to a predetermined opening after the electromagnetic valve of the bypass circuit is opened and the high and low pressures are balanced. .
[0011]
[Action]
In the multi-room air conditioner according to the first aspect, the liquid refrigerant moving from the outdoor heat exchanger to the accumulator through the evaporation temperature generation circuit is substantially eliminated by closing the electronic expansion valve for generating the evaporation temperature to the minimum opening.
[0012]
In the multi-chamber air conditioner according to the second aspect, the liquid refrigerant moving from the outdoor heat exchanger to the accumulator through the evaporation temperature generation circuit is eliminated by closing the electronic expansion valve for generating the evaporation temperature.
[0013]
The multi-chamber air conditioner of claim 3 opens the evaporating temperature generating electronic expansion valve to a predetermined opening after high-low pressure equilibration, so that the evaporating temperature generating electronic expansion valve remains closed when not used for a long time. Don't be.
[0014]
【Example】
Reference example 1 .
( Reference example 1 Overview)
While the air conditioner is stopped, the air conditioner generally opens the electronic expansion valve to equilibrate the high and low pressures in preparation for the next start-up. However, in order to speed up the rise of the cooling (heating) operation after restarting, it is better not to move the refrigerant in the condenser or the evaporator by closing the electronic expansion valve or setting it to the minimum opening degree when stopping. In that case, since the high and low pressures are not balanced, the compressor is difficult to start at the time of restart, but if it is possible to start differential pressure, such as a scroll compressor, it can be started even when high and low pressure are not balanced Become. However, in a severe state in midsummer, the high / low pressure difference is large, and even a compressor capable of starting differential pressure may not be started. For this reason, a Vaspy circuit for balancing high and low pressures is provided, but if a bypass circuit is connected upstream of the accumulator as in the past, the liquid refrigerant in the accumulator is pushed out by the compressor and accumulates in the compressor, causing various adverse effects. give. In this embodiment, therefore, the bypass circuit is connected to the downstream side of the accumulator to prevent the liquid refrigerant in the accumulator from being pushed out to the compressor when the bypass circuit operates and the high and low pressures are balanced.
[0015]
Hereinafter, the present invention Reference example 1 Will be described. FIG. 1 illustrates the present invention. Reference example 1 Is a refrigerant circuit diagram of an air conditioner, in which the reference numerals 1 to 7 are the same as those of the conventional apparatus, and the description thereof is omitted. Reference numeral 12 denotes a double pipe heat exchanger for exchanging heat between the liquefied high-pressure refrigerant and the gas pipe side refrigerant to obtain a large subcool. An important point different from the conventional apparatus is that a bypass circuit composed of the

capillaries

8 and 10 and the electromagnetic valve 9 is connected to the outlet side of the accumulator 6.
The compressor 1, the four-way valve 2, the electronic expansion valves 4a to 4c, and the electromagnetic valve 9 are controlled by signals from a control board 20 (microcomputer) as shown in FIG.
[0016]
Next, the operation will be described. During operation of the compressor 1, the solenoid valve 9 of the bypass circuit is closed and the bypass circuit does not operate. In the flowchart of FIG. 3, when the switch is turned off in step 30, the compressor 1 is stopped (step 31). Subsequently, in step 32, the electronic expansion valves 4a to 4c are closed to the minimum opening, and each heat exchanger is closed. Prevent the refrigerant from moving. Then, for the purpose of facilitating restart, the solenoid valve 9 of the bypass circuit is opened, and the high-pressure refrigerant gas is caused to flow to the suction side of the compressor 1 to balance the discharge side and suction side of the compressor 1 (step 33). At this time, since the refrigerant that has passed through the bypass circuit does not pass through the accumulator 6, the refrigerant liquid in the accumulator 6 does not flow into the compressor 1.
Like this Reference example Then, in order to speed up the start-up of the operation after starting, the electronic expansion valves 4a to 4c are closed to the minimum opening degree when the compressor 1 is stopped, so that, for example, a scroll type compressor capable of starting differential pressure is suitable. In order to ensure that the high pressure and the low pressure are forcibly balanced by the bypass circuit, for example, a rotary compressor that is not suitable for differential pressure activation can be used.
In addition, when the compressor 1 is stopped, the electronic expansion valves 4a to 4c are not fully closed, and the minimum opening is set to the minimum opening degree when the air conditioner is not used and the state is fully closed for a long time. It is because it may become defective.
[0017]
this Reference example According to the present invention, when the compressor 1 is stopped, the electronic expansion valves 4a to 4c are closed to the minimum opening, and a bypass circuit provided for facilitating the start-up to balance high and low pressures is provided on the discharge side of the compressor 1. Since the liquid refrigerant in the accumulator 6 is not pushed out to the compressor 1 when the bypass circuit is operated, the lack of lubricating oil when the compressor 1 is restarted can be prevented.
[0018]
Reference example 2 .
( Reference example 2 Overview)
Reference example 1 In this case, the electronic expansion valve of the main circuit is closed to the minimum opening degree when the compressor is stopped. However, there is a problem of refrigerant noise because there is some movement of the refrigerant in the evaporator (indoor heat exchanger). Therefore, in this embodiment, the refrigerant sound of the evaporator is eliminated by closing the electronic expansion valve of the main circuit when the compressor is stopped.
[0019]
Hereinafter, the present invention Reference example 2 Will be described with reference to FIG. Since the configuration of the refrigerant circuit is exactly the same as that of the first embodiment, the description thereof is omitted.
[0020]
Next, the operation will be described with reference to the flowchart of FIG. When the switch is turned off in step 40, the compressor 1 is stopped in step 41, and then in step 42, the electronic expansion valves 4a to 4c are completely closed in order to prevent the refrigerant from moving in each heat exchanger. . Since the refrigerant does not move in the evaporator (indoor heat exchanger) by closing the electronic expansion valves 4a to 4c, no refrigerant noise is generated. In step 43, the solenoid valve 9 of the bypass circuit is opened in order to balance the high and low pressures to facilitate restarting. They are, Reference example 1 It is the same.
[0021]
this Reference example According to the above, when the compressor 1 is stopped, the electronic expansion valves 4a to 4c are completely closed, and further, the electromagnetic valve 9 of the bypass circuit connected from the discharge side of the compressor 1 to the outlet side of the accumulator 6 is opened. In addition to the same effects as in the first embodiment, it is possible to prevent refrigerant noise in the evaporator (indoor heat exchangers 5a to 5c) when the compressor 1 is stopped.
[0022]
Reference example 3 .
In addition, Reference example 2 However, when the compressor 1 is stopped, the electronic expansion valves 4a to 4c are completely closed. However, when the air conditioner is not used for a long period of time, the electronic expansion valves 4a to 4c remain closed due to mechanical causes. Since malfunction may occur, the electronic expansion valves 4a to 4c are closed when the compressor 1 is stopped, and then the electromagnetic valve 9 is opened to open the electronic expansion valves 4a to 4c to a predetermined opening when the high and low pressures are balanced. You may do it. A flowchart in this case is shown in FIG. A step 44 for opening the electronic expansion valves 4a to 4c to a predetermined opening is added to the flowchart of FIG.
[0023]
Example 1 .
( Example 1 Overview)
Reference examples 1 and 2 In the case of a multi-type air conditioner, for example, if there is an indoor unit that is not used, excess refrigerant accumulates in the accumulator and the liquid level rises to generate the evaporation temperature. The influence of the liquid refrigerant flowing from the outdoor heat exchanger to the accumulator when the compressor is stopped through the circuit cannot be ignored. This embodiment uses an electronic expansion valve in place of the capillary tube of the evaporation temperature generation circuit to prevent this, and prevents liquid refrigerant from flowing from the outdoor heat exchanger to the accumulator through the evaporation temperature generation circuit when the compressor is stopped. .
[0024]
Hereinafter, the present invention Example 1 Will be described with reference to FIG. FIG. 6 is a refrigerant circuit diagram of an air conditioner according to Embodiment 4 of the present invention. In the figure, except for reference numeral 11 Reference example 1 1 is exactly the same as FIG. 1, and the description thereof is omitted. Reference numeral 11 denotes an electronic expansion valve provided in an evaporation temperature generating circuit having one end connected between the outdoor heat exchanger 3 and the electronic expansion valves 4a to 4c and the other end connected to the inlet side of the accumulator.
[0025]
Next, the operation will be described with reference to the flowchart of FIG. When the switch is turned off at step 50, the compressor 1 is stopped at step 51, Reference example 1 Or Reference example 2 For the same purpose, the electronic expansion valves 4a to 4c are closed to the minimum opening or are closed in step 52. Furthermore, by closing the electronic expansion valve 11 to the minimum opening degree in step 53, the liquid refrigerant overflows from the accumulator 6 while suppressing the liquid refrigerant from flowing from the indoor heat exchanger 3 through the evaporation temperature generation circuit to the accumulator 6 as much as possible. To prevent. In step 54, the solenoid valve 9 of the bypass circuit is opened to balance the high and low pressures.
The reason why the electronic expansion valve 11 is not fully closed is that Reference example 1 For the same reason as the case of the electronic expansion valves 4a to 4c.
[0026]
According to this embodiment, when the compressor 1 is stopped, the electronic expansion valves 4a to 4c are closed to the minimum opening degree or closed to suppress the movement of the refrigerant of each heat exchanger, and the electrons of the evaporation temperature generation circuit Since the expansion valve 11 is closed to the minimum opening, even when there is an indoor unit that is not used and the liquid level of the accumulator 6 becomes high, the refrigerant liquid is prevented from overflowing from the accumulator 6.
[0027]
Example 2 .
In addition, Example 1 In the above description, the electronic expansion valve 11 is closed to the minimum opening, but may be completely closed. FIG. 8 shows a flowchart in that case. If it does in this way, the liquid refrigerant which flows into the accumulator 6 through the evaporation temperature production | generation circuit from the outdoor heat exchanger 3 at the time of the stop of the compressor 1 can be eliminated.
[0028]
Example 3 .
Also, Example 2 After the solenoid valve 9 of the bypass circuit is opened, the air conditioner is not used for a long time by opening the electronic expansion valve 11 after the high / low pressure balance at a predetermined opening in step 65 as shown in the flowchart of FIG. In this case, it is possible to prevent mechanical malfunction of the electronic expansion valve 11.
[0029]
Reference example 4 .
( Reference example 4 Overview)
this Reference example Provides a temperature sensor on the gas piping side of each indoor unit, detects the temperature of each gas pipe, and compares the evaporation temperature with the evaporation temperature sensor to determine each indoor outlet SH (superheat degree). Is used as a reference value, and a tolerance of the other indoor outlet SH with the reference value is obtained. And the correction | amendment of the electronic expansion valve of each indoor unit is repeated until each indoor exit SH tolerance enters into the target range also including suction | inhalation SH and discharge temperature. In this way, even when there is a difference in indoor load fluctuation / extension piping, each indoor unit outlet SH is kept within a certain range to prevent the occurrence of dew jumping, capacity reduction, etc. occurring in the indoor unit.
[0030]
Hereinafter, the present invention Reference example 4 Will be described with reference to FIG. FIG. 10 shows the present invention. Reference example 4 It is a refrigerant circuit figure of the air conditioner by. In the figure, reference numerals 1 to 7 and 14 are the same as those of the conventional apparatus, and the description thereof is omitted. 15 is an evaporation temperature sensor that branches from between the outdoor heat exchanger 3 and the electronic expansion valves 4a to 4c, is connected to the suction side of the compressor 1, and detects the evaporation temperature of the evaporation temperature generation circuit provided with the capillary tube 7. 16a to 16c are gas pipe temperature sensors for detecting the outlet temperatures of the indoor heat exchangers 5a to 5c, 21 is a discharge temperature sensor for detecting the discharge temperature of the

compressor

1, and 30 is a controller for controlling the electronic expansion valve.
[0031]
Next, the operation will be described.
The output values of the intake refrigerant temperature sensor 14, the evaporation temperature sensor 15, the gas pipe temperature sensors 16a to 16c and the discharge temperature sensor 21 are input to the controller 30 for electronic expansion valve control, and the electronic expansion valves 4a to 4a are operated according to the procedure described below. The valve opening degree control of 4c is performed. The contents of the valve opening control will be described. The calculation formulas of the intake SH, each indoor outlet SH (a, b, c), and each indoor outlet SH tolerance (a, b, c) used for the description are (1) to (3) It defines with a formula.
[0032]
[Expression 1]

[0033]
The contents of the valve opening control will be described with reference to the flowchart of FIG. In step 100, the operation of the indoor unit is started. Next, in step 101, the controller 30 sets the opening degree of the electronic expansion valves 4a to 4c and the initial value of the operation frequency of the compressor 1. In this case, the opening ratio of the electronic expansion valves 4a to 4c is changed by the capacity of the indoor unit. In step 102, it is checked whether the suction SH defined by the equation (1) is within the target value range, and in step 103, the opening correction of the electronic expansion valves 4a to 4c is performed uniformly according to FIG. 13 (a). . Next, in step 104, it is checked whether the discharge temperature is within the target value range, and in step 105, the opening degrees of the electronic expansion valves 4a to 4c are each uniformly corrected according to FIG. 13 (b). After the process of step 105 is finished, each indoor outlet SH (a, b, c) defined by equation (2) and each indoor outlet SH tolerance (a, b, c) defined by equation (3) are calculated. In step 106a, it is determined whether each indoor outlet SH tolerance (a, b, c) is within the target range. If it is not within the target range, the opening of the electronic expansion valves 4a to 4c other than the minimum value is corrected in step 107a according to FIG. 13 (c). If it is within the target range, it is determined at step 108 whether the intake SH and the discharge temperature are within the target values. If they are within the target values, the openings of the electronic expansion valves 4a-4c are fixed at step 109. If the target value is not reached, the process returns to step 102, and the above process is repeated until all of the suction SH, the discharge temperature, and the indoor outlet SH tolerances reach the target value.
[0034]
This is because the control is performed so that the outlet SH of the other indoor units is brought close to this with the minimum value of the indoor outlet SH as a reference value. The minimum value of the indoor outlet SH is the degree of superheat of the intake temperature of the compressor 1 (intake SH). Therefore, if the tolerance with the minimum value falls within the target range, each indoor outlet SH becomes an appropriate value, and the temperature distribution of each indoor heat exchanger There is no unevenness, and it is possible to prevent dew jumping and capacity reduction.
[0035]
Reference Example 5 .
Reference example 4 Then, although correction | amendment of the electronic expansion valves 4a-4c was performed using the indoor exit SH tolerance, you may use a gas pipe temperature tolerance instead of the indoor exit SH tolerance.
The refrigerant circuit diagram is the same as FIG.
The gas pipe temperature tolerance used to explain the contents of the control is defined by equation (4).
[0036]
[Expression 2]

[0037]
The contents of the valve opening degree control will be described based on the flowchart of FIG. Except for

steps

106b and 107b, it is exactly the same as the flowchart of FIG. 11. In step 106b, it is determined whether each gas pipe temperature (a, b, c) defined by equation (4) is within the target range. If it is not within the range, the opening of the electronic expansion valves (4a, 4b, 4c) except for the minimum value is corrected in step 107b according to FIG. 13 (d). If each gas pipe temperature (a, b, c) is not within the target range, go to step 8. Since other processes are the same as those in FIG.
[0038]
This uses the gas pipe temperature tolerance instead of the indoor outlet SH tolerance. Reference example The basic function and effect, that is, the temperature distribution of the indoor heat exchanger is made uniform to prevent dew and prevent the capacity from being reduced. Reference example 4 Is the same as Reference Example 5 In this case, since the gas pipe temperature tolerance is used instead of the indoor outlet SH, it is not necessary to compare the detection temperature of the gas pipe temperature sensors (16a to 16c) with the detection temperature of the evaporation temperature sensor 15, and the calculation process is simplified. There is an effect.
[0039]
【The invention's effect】
The multi-room air conditioner according to claim 1 is a compressor, a four-way valve, an outdoor heat exchanger. An electronic expansion valve that adjusts the flow rate of refrigerant and an accumulator are connected in series between the branch pipes branched in parallel from the main circuit to form a refrigerant circuit, and one end is connected between the outdoor heat exchanger and the electronic expansion valve The other end is connected to the inlet side of the accumulator. In a multi-room air conditioner having an outdoor unit and an indoor unit in which an indoor heat exchanger is connected to each of the electronic expansion valves, the evaporation temperature generation circuit has an electronic expansion valve for generating the evaporation temperature, and the compressor and the four-way valve And a bypass circuit having a solenoid valve and a capillary tube closed during operation of the compressor and when the compressor is stopped, the electronic expansion valve is closed to the minimum opening or when the compressor is stopped. A control means for closing the valve, closing the evaporating temperature generating electronic expansion valve to the minimum opening degree, and further opening the electromagnetic valve of the bypass circuit in order to prevent liquid refrigerant from flowing into the accumulator from the outdoor heat exchanger Therefore, even when surplus refrigerant is accumulated in the accumulator, there is no fear that the refrigerant liquid overflows from the accumulator, and it is possible to prevent deterioration in the lubrication performance of the compressor.
[0040]
The multi-room air conditioner according to claim 2 includes a compressor, a four-way valve, and an outdoor heat exchanger. An electronic expansion valve that adjusts the flow rate of refrigerant and an accumulator are connected in series between the branch pipes branched in parallel from the main circuit to form a refrigerant circuit, and one end is connected between the outdoor heat exchanger and the electronic expansion valve The other end is connected to the inlet side of the accumulator. In a multi-room air conditioner having an outdoor unit and an indoor unit in which an indoor heat exchanger is connected to each of the electronic expansion valves, the evaporation temperature generation circuit has an electronic expansion valve for generating the evaporation temperature, and the compressor and the four-way valve And a bypass circuit having a solenoid valve and a capillary tube closed during operation of the compressor and when the compressor is stopped, the electronic expansion valve is closed to the minimum opening or when the compressor is stopped. Since the valve is closed, the electronic expansion valve for generating the evaporation temperature is closed in order to prevent the liquid refrigerant from flowing from the outdoor heat exchanger to the accumulator, and the control means for opening the electromagnetic valve of the bypass circuit is provided. Even when surplus refrigerant is accumulated in the accumulator, the refrigerant liquid does not overflow from the accumulator, and a reduction in the lubricating performance of the compressor can be prevented.
[0041]
The multi-chamber air conditioner according to claim 3 is the structure according to claim 2, wherein the control means opens the electromagnetic valve of the bypass circuit and opens the electronic expansion valve for generating the evaporation temperature to a predetermined opening after the high and low pressures are balanced. Therefore, it is possible to eliminate the mechanical malfunction of the evaporating temperature generating electronic expansion valve when the air conditioner is not used for a long time.
[Brief description of the drawings]
FIG. 1 of the present invention Reference example 1 It is a refrigerant circuit diagram of the multi-room air conditioner by.
FIG. 2 of the present invention Reference example 1 It is a control block diagram of the multi-room air conditioner by.
FIG. 3 of the present invention Reference example 1 It is a flowchart figure which shows the control content of the multi-room air conditioner by.
FIG. 4 of the present invention Reference example 2 It is a flowchart figure which shows the control content of the multi-room air conditioner by.
FIG. 5 of the present invention Reference example 3 It is a flowchart figure which shows the control content of the multi-room air conditioner by.
FIG. 6 of the present invention Example 1 It is a refrigerant circuit diagram of the multi-room air conditioner by.
FIG. 7 of the present invention Example 1 It is a flowchart figure which shows the control content of the multi-room air conditioner by.
FIG. 8 of the present invention Example 2 It is a flowchart figure which shows the control content of the multi-room air conditioner by.
FIG. 9 shows the present invention. Example 3 It is a flowchart figure which shows the control content of the multi-room air conditioner by.
FIG. 10 shows the present invention. Reference example 4 It is a refrigerant circuit diagram of the multi-room air conditioner by.
FIG. 11 shows the present invention. Reference example 4 It is a flowchart figure which shows the control content of the multi-room air conditioner by.
FIG. 12 shows the present invention. Reference Example 5 It is a flowchart figure which shows the control content of the multi-room air conditioner by.
FIG. 13 shows the present invention. Reference examples 4 and 5 It is a figure which shows the specific operation | movement of the control of the multi-room air conditioner by.
FIG. 14 is a refrigerant circuit diagram of a conventional multi-room air conditioner (conventional example 1).
FIG. 15 is a refrigerant circuit diagram of a conventional multi-room air conditioner (conventional example 2).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Compressor, 2 Four way valve, 3 Outdoor heat exchanger, 4a-4c Electronic expansion valve, 5a-5c Indoor heat exchanger, 6 Accumulator, 9 Solenoid valve, 11 Electronic expansion valve for evaporating temperature generation, 14 Inhalation temperature sensor, 15 Evaporation temperature sensor, 16a-16c Gas pipe temperature sensor, 21 Discharge temperature sensor.

Claims

A compressor circuit , a four-way valve, an outdoor heat exchanger , an electronic expansion valve that adjusts the flow rate of refrigerant between the branch pipes branched in parallel from the main circuit, and an accumulator are sequentially connected to form a refrigerant circuit, and the outdoor heat exchanger And an outdoor unit capable of switching between heating and cooling provided with an evaporation temperature generating circuit having one end connected between the electronic expansion valve and the other end connected to the inlet side of the accumulator, and indoor heat exchange for each of the electronic expansion valves In the multi-room air conditioner having an indoor unit connected to the chamber, the evaporating temperature generating circuit includes an evaporating temperature generating electronic expansion valve, and between the compressor and the four-way valve and between the compressor and the accumulator. A bypass circuit having a solenoid valve and a capillary tube that are closed during operation of the compressor, and when the compressor is stopped, the electronic expansion valve is closed to a minimum opening or the electronic expansion valve is closed, Outdoor heat exchange Control means for closing the evaporating temperature generating electronic expansion valve to a minimum opening degree and further opening the electromagnetic valve of the bypass circuit in order to prevent liquid refrigerant from flowing into the accumulator Multi-room air conditioner.

A compressor circuit , a four-way valve, an outdoor heat exchanger , an electronic expansion valve that adjusts the flow rate of refrigerant between the branch pipes branched in parallel from the main circuit, and an accumulator are sequentially connected to form a refrigerant circuit, and the outdoor heat exchanger And an outdoor unit capable of switching between heating and cooling provided with an evaporation temperature generating circuit having one end connected between the electronic expansion valve and the other end connected to the inlet side of the accumulator, and indoor heat exchange for each of the electronic expansion valves In the multi-room air conditioner having an indoor unit connected to the chamber, the evaporating temperature generating circuit includes an evaporating temperature generating electronic expansion valve, and between the compressor and the four-way valve and between the compressor and the accumulator. A bypass circuit having a solenoid valve and a capillary tube that are closed during operation of the compressor, and when the compressor is stopped, the electronic expansion valve is closed to a minimum opening or the electronic expansion valve is closed, Outdoor heat exchange Control means for closing the evaporating temperature generating electronic expansion valve and further opening the electromagnetic valve of the bypass circuit in order to prevent liquid refrigerant from flowing into the accumulator from the multi-chamber air Harmony machine.

3. The multi-chamber air conditioner according to claim 2 , wherein the control means opens the electronic expansion valve for generating the evaporation temperature to a predetermined opening after the electromagnetic valve of the bypass circuit is opened and the high and low pressures are balanced.