JP4131630B2

JP4131630B2 - Multi-chamber air conditioner and control method thereof

Info

Publication number: JP4131630B2
Application number: JP2002049743A
Authority: JP
Inventors: 健二白井; 徳哉浅田; 康裕中村; 義和西原; 博荒島
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2002-02-26
Filing date: 2002-02-26
Publication date: 2008-08-13
Anticipated expiration: 2022-02-26
Also published as: JP2003247742A

Description

【０００１】
【発明の属する技術分野】
本発明は、１台の室外機に複数台の室内機を接続し、圧縮機容量（周波数）制御で能力を制御する多室形空気調和装置及びその制御方法に関するものである。
【０００２】
【従来の技術】
従来、１台の室外機に複数台の室内機を接続した多室形空気調和装置において、容量可変圧縮機を用い、冷凍サイクルの液側冷媒配管に、各室内機への冷媒流量を制御する冷媒流量制御弁を設け、室内からの要求負荷に応じて、最大負荷の室内機があるなかで室外機の能力に余裕がある場合には、その能力余裕分を最大負荷の室内機に供給するように圧縮機容量を制御するものが提案されている（例えば特開平９−１４５１３０号公報）。
【０００３】
以下、図面を参照しながら上記従来の多室形空気調和装置について説明する。図４は、従来の多室形空気調和装置の冷凍サイクル図である。この多室形空気調和装置は１台の室外機２０に複数台（図４では、３台）の室内機２１ａ、２１ｂ、２１cを接続して構成されている。室外機２０内には、インバータ駆動の周波数可変形圧縮機２２（以下単に圧縮機と称す）、室外熱交換器２３、冷暖房切り替え用の四方弁２４が設けられる一方、室内機２１ａ、２１ｂ、２１ｃ内にはそれぞれ室内熱交換器２５ａ、２５ｂ、２５ｃが設けられている。室外機２０と室内機２１a、２１ｂ、２１cとは、室外機２０内に設けた液側主管２６より分岐した液側分岐管２７a、２７b、２７cおよび室外機２０内に設けたガス側主管２８より分岐したガス側分岐管２９a、２９b、２９cとで接続されている。液側分岐管２７a、２７b、２７cには、弁開度を電気的に制御可能な電動膨張弁３０a、３０b、３０cをそれぞれ介装し、また液側主管２６上には冷媒液を貯留可能なレシーバ３１を設け、このレシーバ３１を冷暖房共中間圧に保つために補助絞り３２が設けられている。
【０００４】
また、レシーバ３１と圧縮機２２への吸入管３３とを結ぶバイパス回路３４が設けられ、このバイパス回路３４には補助絞り３５が設けられている。各室内機２１a、２１b、２１cには各室内機２１a、２１b、２１cが設置されている部屋の室温を検出する室内温度センサ３６a、３６b、３６cおよび居住者が希望する運転モード（冷房または暖房）と室温と運転、停止を設定できる運転設定回路３７a、３７b、３７cが設けられている。
【０００５】
上記冷凍サイクルにおいて、冷房時は圧縮機２２から吐出された冷媒は、四方弁２４より室外熱交換器２３へと流れてここで室外空気と熱交換して凝縮液化し、補助絞り３２で減圧されて中間圧となる。そして、レシーバ３１に一部の液冷媒を貯留し、残りは液側分岐管２７a、２７b、２７cへと分岐する。電動膨張弁３０a、３０b、３０cの弁開度は、後述する制御方法でそれぞれの部屋の負荷に見合った開度になるように制御されるため、冷媒もそれぞれの負荷に応じた流量で低圧となって室内熱交換器２５a、２５b、２５cへと流れて蒸発した後、ガス側分岐管２９a、２９b、２９cよりガス側主管２８、四方弁２４を通過して再び圧縮機２２に吸入される。また、レシーバ３１からごくわずかの液冷媒がバイパス回路３４へと流れ、補助絞り３５で減圧されて吸入管３３へと流れる。圧縮機周波数は総負荷に応じて後述する制御方法で決定される。
【０００６】
一方、暖房時は四方弁２４が切り替えられ、圧縮機２２から吐出された冷媒は、ガス側主管２８よりガス側分岐管２９a、２９b、２９cへと分岐し、室内熱交換器２５a、２５b、２５cへと流れて凝縮液化し、液側分岐管２７a、２７b、２７c上の電動膨張弁３０a、３０b、３０cで減圧されて中間圧となる。電動膨張弁３０a、３０b、３０cの弁開度は冷房時と同様に後述する制御方法でそれぞれの部屋の負荷に見合った開度に制御されるため、冷媒もそれに応じた流量で室内熱交換器２５a、２５b、２５cを流れる。中間圧となった冷媒は、レシーバ３１に一部の液冷媒が貯留され、残りは補助絞り３２で減圧されて低圧となって室外熱交換器２３を流れて蒸発した後、四方弁２４を通過して再び圧縮機２２に吸入される。また、レシーバ３１からごくわずかの液冷媒がバイパス回路３４へと流れ、補助絞り３５で減圧されて吸入管３３へと流れる。圧縮機周波数は冷房時と同様に総負荷に応じて後述する制御方法で決定される。
【０００７】
図５は従来例の圧縮機周波数および電動膨張弁開度の制御の流れを示すブロック図であり、図６は従来例の室内温度Ｔrと設定温度Ｔsとの差温△Ｔの温度ゾーン分割図である。
【０００８】
まず、室内機２１ａにおいて、室内温度センサ３６ａの出力を室内温度検出回路４１より温度信号Ｔｒとして差温演算回路４２に送出するとともに、設定判別回路４３にて運転設定回路３７ａで設定された設定温度Ｔｓおよび運転モードを判別して、差温演算回路４２に送出する。差温演算回路４２では、差温△Ｔ（＝Ｔｒ−Ｔｓ）を算出し、図６に示す負荷ナンバーＬｎ値に変換してこれを差温信号とする。たとえば、冷房運転時でＴｒ＝２９．３℃、Ｔｓ＝２６℃とすると、差温△Ｔ＝３．３℃で空調負荷極大ゾーンＬｎ＝８となる。また、ＯＮ―ＯＦＦ判別回路４４にて、運転設定回路３７ａで設定された室内機２１ａの運転（ＯＮ）または停止（ＯＦＦ）を判別し、さらに定格容量記憶回路４５に室内機２１ａの定格容量を記憶しておき、これらの定格容量信号、差温信号、運転モード信号、ＯＮ―ＯＦＦ判別信号を信号送出回路４６より室外機２０の信号受信回路４７へ送る。室内機２１ｂ、２１ｃからも同様の信号が信号受信回路４７へ送られる。信号受信回路４７で受信した信号は、圧縮機周波数演算回路４８と膨張弁開度演算回路４９へ送出される。ただし、異なる運転モード信号が存在する場合、最初に運転を開始した室内機の運転モードが優先され、異なる運転モードの室内機は停止しているとみなしてＯＮ―ＯＦＦ判別回路４４は常にＯＦＦの信号を送出する。
【０００９】
圧縮機周波数演算回路４８にて室内機２１ａ、２１ｂ、２１ｃのそれぞれの定格容量信号、差温信号、運転モード信号、ＯＮ―ＯＦＦ判別信号より表１に示す負荷定数テーブル５０から負荷定数を読み出し、この負荷定数の総和に定数を乗じて圧縮機２２の周波数を決定する。
【表１】

【００１０】
一例として、冷房時の運転開始時において、室内機２１ａ、２１ｂ、２１ｃからの信号が表２の場合について説明する。
【表２】

【００１１】
表１と表２より、室内機２１ａ、２１ｂ、２１ｃの負荷定数はそれぞれ２．４，３．０，０となり、したがって圧縮機２２の周波数Ｈｚは、Ａを定数とするとＨｚ＝Ａ×（２．４＋３．０＋０）＝Ａ×５．４となる。圧縮機２２の運転許容値は室内機２１ａ、２１ｂ、２１ｃの定格容量に相当する２．０，２．５，３．２の合計値７．７とすれば、周波数の演算結果は圧縮機２２の運転許容値に達しておらず、約３割の余裕度を残しており、この演算結果を周波数信号として圧縮機駆動回路（図示せず）に送出して、圧縮機２２の周波数制御を行う。以降、所定周期毎に室内機２１ａ、２１ｂ、２１ｃのそれぞれの定格容量信号、差温信号、運転モード信号、ＯＮ―ＯＦＦ判別信号より演算を行い、稼動中の室内機２台ともＬｎ＝７になるまで上記周波数を継続し、演算結果を周波数信号として圧縮機駆動回路（図示せず）に送出して圧縮機２２の周波数制御を行う。
【００１２】
次に、表３のように室内機２１ａ、２１ｂが低負荷で運転中に、室内機２１ｃを運転開始した場合について説明する。
【表３】

【００１３】
表１と表２より、室内機２１ａ、２１ｂ、２１ｃの負荷定数はそれぞれ０．８，１．０，３．８となり、したがって圧縮機２２の周波数Ｈｚは、同様にＨｚ＝Ａ×（０．８＋１．０＋３．８）＝Ａ×５．６となり、周波数の演算結果は圧縮機２２の運転許容値に達しておらず、約３割の余裕度を残しており、この演算結果を周波数信号として圧縮機駆動回路（図示せず）に送出して、圧縮機２２の周波数制御を行う。以降、所定周期毎に室内機２１ａ、２１ｂ、２１ｃのそれぞれの定格容量信号、差温信号、運転モード信号、ＯＮ―ＯＦＦ判別信号より演算を行い、室内機２１ａ、２１ｂの負荷が同じであれば、室内機２１ｃがＬｎ＝７になるまで上記周波数を継続し、演算結果を周波数信号として圧縮機駆動回路（図示せず）に送出して圧縮機２２の周波数制御を行う。なお、室内機２１ａ、２１ｂの負荷がＬｎ＝７の場合には、Ｈｚ＝Ａ×（２．０＋２．５＋３．８）＝Ａ×８．３となり、圧縮機２２の運転許容値を越えるため、圧縮機２２の運転許容値Ｈｚ＝７．７に対応する周波数信号を圧縮機駆動回路に送出して、圧縮機２２の周波数制御を行う。
【００１４】
膨張弁開度演算回路４９においても同様に、室内機２１ａ、２１ｂ、２１ｃそれぞれの定格容量信号、差温信号、運転モード信号、ＯＮ―ＯＦＦ判別信号より表１に示す負荷定数テーブル５０から負荷定数を選び、さらに室内機２１ａ、２１ｂ、２１ｃそれぞれの定格容量より、表４に示す定格容量毎の弁初期開度テーブル５１から読み出す。なお、弁初期開度は、異なる定格容量の室内機の組み合わせでも、各室内機が所定の能力制御ができるように決定する。
【表４】

【００１５】
電動膨張弁３０ａ、３０ｂ、３０ｃの弁開度はそれぞれの負荷定数をその負荷定数の所定値で除したものに弁初期開度を乗じたものである。圧縮機周波数算出例の場合と同様に、まず室内機２１ａ、２１ｂ、１ｃからの信号が表２の場合について説明する。
【００１６】
室内機２１ａ、２１ｂ、２１ｃの（負荷定数/所定負荷定数）はそれぞれ（２．４／２．０）、（３．０／２．５）、（０／３．２）であり、弁初期開度はそれぞれ１００、１３０、１８０であるので、電動膨張弁３０ａ、３０ｂ、３０ｃの弁開度は、１２０、１５６、０となる。この演算結果を膨張弁開度信号として膨張弁駆動回路（図示せず）に送出する。以降、所定周期毎に、差温信号、運転モード信号、ＯＮ―ＯＦＦ判別信号より電動膨張弁３０ａ、３０ｂ、３０ｃの弁開度を算出し、これらの演算結果を膨張弁開度信号として膨張弁駆動回路（図示せず）に送出する。
【００１７】
次に、表３の場合について説明する。表２の場合と同様に、室内機２１ａ、２１ｂ、２１ｃの（負荷定数/所定負荷定数）はそれぞれ（０．８／２．０）、（１．０／２．５）、（３．８／３．２）であり、弁初期開度はそれぞれ１００、１３０、１８０であるので、電動膨張弁３０ａ、３０ｂ、３０ｃの弁開度は、４０、５２、２１４となる（小数点以下第一位を四捨五入）。この演算結果を膨張弁開度信号として膨張弁駆動回路（図示せず）に送出する。以降、所定周期毎に、差温信号、運転モード信号、ＯＮ―ＯＦＦ判別信号より電動膨張弁３０ａ、３０ｂ、３０ｃの弁開度を算出し、これらの演算結果を膨張弁開度信号として膨張弁駆動回路（図示せず）に送出する。
【００１８】
このように、負荷の少ない室内機に対しては、その負荷に応じた能力を供給し、空調負荷極大ゾーンにある室内機にのみ、室内機の定格容量を上回る能力を目標に、余裕ある室外能力を供給するよう圧縮機周波数を制御するため、設定温度に到達するまでの時間を早くすることができ、快適性の向上および省エネルギーを図ることができる。
【００１９】
【発明が解決しようとする課題】
しかしながら、上記従来の多室形空気調和装置には以下のような課題があった。すなわち、例えば冷房運転で室内機２１ａの差温信号がＬｎ＝６で運転中に、室内機２１ｂが最大負荷で運転開始した後、室内機２１ａの負荷が低下した場合、室内機２１ｂの負荷が最大で能力が欲しいにも関わらず、室内機２１ａの負荷が低下するに従い圧縮機容量（周波数）が低下し、室内機２１ｂが設定温度に達するのに多くの時間を要してしまう。
【００２０】
図７（ａ）は、従来の制御方法による暖房時の圧縮機周波数、吸込み、吹き出し温度変化図であり、高負荷側の吸込み、吹き出し温度は上がっておらず負荷が高いままなのに低負荷側の負荷低下により周波数が低下していることが分かる。つまり、膨張弁開度で能力の欲しい室内機２１ｂ側に冷媒を多く分配しても室内機容量への依存度は圧縮機容量（周波数）が支配的なため、ある室内機の負荷が低下する場合は圧縮機容量（周波数）が低下してしまい、負荷が低下した室内だけでなく最大能力が必要な他の室内機の容量も低下してしまっていた。
【００２１】
本発明は、従来技術の有するこのような問題点に鑑みてなされたものであり、ある室内の負荷が大きいが他室の負荷が下がっている場合でも圧縮機容量（周波数）をアップし、負荷の大きい部屋が設定温度に達する時間を短縮することのできる快適性の向上した多室形空気調和装置及びその制御方法を提供することを目的としている。
【００２２】
【課題を解決するための手段】
上記目的を達成するために、本発明は、容量可変圧縮機と室外熱交換器を有する１台の室外機と、室内熱交換器を有する複数台の室内機とを互いに接続した多室形空気調和機であって、各室内機が設置される室内の温度を任意に設定する室内温度設定手段と、室内温度を検出する室内温度検出手段と、前記室内温度設定手段により設定された温度と前記室内温度検出手段により検出された室内温度との差温を算出する差温演算手段と、各室内機の定格容量を判別する容量判別手段と、各室内機が運転中か停止中かを判別するオンオフ判別手段と、前記差温が取り得る温度範囲を分割した複数個の温度ゾーンの各温度ゾーン毎かつ各室内機の定格容量毎に室内負荷に対応して設定された負荷定数を記憶する負荷定数記憶手段と、前記差温演算手段、前記容量判別手段、前記オンオフ判別手段及び前記負荷定数記憶手段より得られるデータを用いて、運転台数に応じて所定周期毎に前記圧縮機の容量を算出する容量演算手段とを備え、運転中の各室内の温度ゾーンの最大値が所定時間以上所定のゾーン以上を連続した場合に、能力供給中の全室内機の負荷定数に所定値αｉを加算し、該αｉを加算した負荷定数に基づいて前記容量可変圧縮機の容量を制御することを特徴とする。
【００２３】
また、前記αｉの加算回数に上限値を設定し、前記αｉを加算した負荷定数に基づく前記容量可変圧縮機の容量制御を、運転中の各室内の温度ゾ−ンの最大値が所定ゾーン未満のゾーンに低下するまで前記αｉの加算を所定時間ごとに繰り返して行うようにすることもできる。
【００２４】
さらに、前記αｉの加算回数の上限値を各室内の温度ゾーンの最大値のゾーンにより設定し、加算回数上限指定ゾーンで温度ゾーンが上昇した場合、現行のαｉ加算回数を維持するようにしてもよい。
【００２５】
好ましくは、前記室外機と前記複数台の室内機とを、前記室外機に設けられ主に冷媒液が流れる液側主管から分岐した液側分岐管と前記室外機に設けられ主に冷媒ガスが流れるガス側主管から分岐したガス側分岐管を介して接続するとともに、弁開度を電気的に制御可能な電動膨張弁を前記液側分岐管に取り付け、所定時間以上所定温度ゾーン以下の温度ゾーンを連続した室内機については前記電動膨張弁の開度を絞るように設定される。
【００２６】
また、暖房運転時においては、能力供給停止中で室温サンプリング中の室内機にも前記αｉの加算を行い、室温サンプリング終了後前記αｉの加算を解除するようにしてもよい。
【００２７】
さらに、本発明は、容量可変圧縮機と室外熱交換器を有する１台の室外機と、室内熱交換器を有する複数台の室内機とを互いに接続した多室形空気調和装置の制御方法であって、各室内機が設置される室内の設定温度と検出温度との差温に応じて複数個の温度ゾーンを設定するとともに、各温度ゾーン毎に室内負荷に対応する負荷定数を設定し、室内機の運転台数及び各室内機の負荷定数に基づいて容量可変圧縮機の容量を算出し、各室内の温度ゾーンの最大値が所定時間以上所定のゾーン以上を連続した場合に、能力供給中の全室内機の負荷定数に所定値αｉを加算し、該αｉを加算した負荷定数に基づいて容量可変圧縮機の容量を制御することを特徴とする。
【００２８】
この場合、前記室外機に設けられ主に冷媒液が流れる液側主管から分岐した液側分岐管に弁開度を電気的に制御可能な電動膨張弁を取り付け、所定時間以上所定温度ゾーン以下の温度ゾーンを連続した室内機については前記電動膨張弁の開度を絞るようにするのが好ましい。
【００２９】
【発明の実施の形態】
以下、本発明の実施の形態について、図面を参照しながら説明する。
【００３０】
実施の形態１．
本実施の形態にかかる多室形空気調和装置の冷凍サイクル図は、図４に示される従来例と同じであり、本実施の形態においても、１台の室外機２０に３台の室外機２１ａ、２１ｂ、２１ｃを接続した場合について説明する。
【００３１】
図１は圧縮機周波数の制御の流れを示すブロック図であり、図２は室内温度Ｔｒと設定温度Ｔｓとの差温△Ｔの温度ゾーン分割図である。
【００３２】
まず、室内機２１ａにおいて、室内温度センサ３６ａの出力を室内温度検出回路１より温度信号として差温演算回路２に送出するとともに、設定判別回路３にて運転設定回路３７ａで設定された設定温度および運転モードを判別して、差温演算回路２に送出する。差温演算回路２では差温△Ｔ（＝Ｔｒ−Ｔｓ）を算出し、図２に示す温度ゾーン値に変換してこれを差温信号とする。たとえば、冷房運転時でＴｒ＝２９．３℃、Ｔｓ＝２６℃とすると、差温△Ｔ＝３．３℃で温度ゾーンＬｎ＝９となる。また、ＯＮ―ＯＦＦ判別回路４にて、運転設定回路３７ａで設定された室内機２１ａの運転（ＯＮ）または停止（ＯＦＦ）を判別し、さらに定格容量記憶回路５に室内機２１ａの定格容量を記憶しておき、これらの定格容量信号、差温信号、運転モード信号、ＯＮ―ＯＦＦ判別信号を信号送出回路６より室外機２０の信号受信回路７へ送る。室内機２１ｂ、２１ｃからも同様の信号が室外機７の信号受信回路７へ送られる。信号受信回路７で受信した信号は、圧縮機周波数演算回路８と膨張弁開度演算回路９へ送出される。ただし、異なる運転モード信号が存在する場合、最初に運転を開始した室内機の運転モードが優先され、異なる運転モードの室内機は停止しているとみなしてＯＮ―ＯＦＦ判別回路４は常にＯＦＦの信号を送出する。
【００３３】
圧縮機周波数演算回路８にて室内機２１ａ、２１ｂ、２１ｃのそれぞれの定格容量信号、差温信号、運転モード信号、ＯＮ―ＯＦＦ判別信号より表５に示す負荷定数テーブル１０と表６に示す定格容量テーブル４０から負荷定数αｎと定格容量定数Ｑｎを読み出し、この負荷定数αｎと定格容量定数Ｑｎの積により各室の能力負荷定数Ｈｎを次式により求める。
Ｈｎ＝αｎ×Ｑｎ
【００３４】
さらに、次式に示すように各室の能力負荷定数の総和ΣＨｎを求め、ΣＨｎの１次式にて圧縮機２２の周波数を決定する。
ΣＨｎ＝（Ｈ_２１ａ＋Ｈ_２１ｂ＋Ｈ_２１ｃ）
圧縮機周波数＝Ａ×ΣＨｎ＋Ｂ（Ａ、Ｂは定数）
【００３５】
【表５】

【表６】

【００３６】
このとき、表７に一例を示すように運転中の各室内の温度ゾーンの最大値が所定時間Ｔmaxα一定の高いゾーンＺmaxα以上を連続した場合に能力供給中の全室内機の負荷定数に一定値αｉを加算する。従って各室の能力負荷係数Ｈｎは
Ｈｎ＝（αｎ＋αｉ）×Ｑｎ
【表７】

【００３７】
一例として、暖房時の室内機２１ａ、２１ｂ、２１ｃからの信号が表８の場合について説明する。
【表８】

【００３８】
表５、表６より、室内機２１ａ、２１ｂ、２１ｃの能力負荷係数はＨ_２１ａ＝２２×１．００＝２２．０、Ｈ_２１ｂ＝２２×１．００＝２２．０、Ｈ_２１ｃ＝０であるからΣＨｎ＝４４．０であるが、室内機２１ａの温度ゾーンが８から７に低下すると、Ｈ_２１ａ＝１８×１．００＝１８．０となり、ΣＨｎ＝４０．０となる。この場合、従来の制御では、室内機２１ｂは最大負荷が続いているにかかわらず圧縮機周波数が低下することになる。
【００３９】
しかしながら、本実施の形態においては、温度ゾーン８以上が３分以上継続している室内機が１台でもあれば、能力供給中の全室内機の負荷定数にαｉ＝３を追加するため、Ｈ_２１ａ＝（２２＋３）×１．００＝２５．０、Ｈ_２１ｂ＝（１８＋３）×１．００＝２１．０となり、ΣＨｎ＝２５．０＋２１．０＝４６．０となる。この演算結果を周波数信号として圧縮機駆動回路（図示せず）に送出して、圧縮機２２の周波数制御を行う。以降、所定周期毎に室内機２１ａ、２１ｂ、２１ｃのそれぞれの定格容量信号、差温信号、運転モード信号、ＯＮ―ＯＦＦ判別信号より演算を行い、各室内機の温度ゾーンの最大値が８未満に低下するまで能力供給中の全室内機の負荷定数にαｉを追加して圧縮機２２の周波数制御を行う。
【００４０】
図７（ｂ）は、本実施の形態にかかる上記制御を実施した場合の暖房時の周波数、吸込み、吹き出し温度変化図であり、低負荷側の負荷が低下しても高負荷側の負荷が高い場合は圧縮機容量（周波数）が上昇していることがわかる。
【００４１】
上記説明は、主に暖房時について行ったが、冷房時についても同様に制御可能である。また、表７に示すＴmaxα、Ｚmaxα、αｉの定数を変更することでさらに圧縮機周波数制御の幅を広げることができる。このように、ある室内の負荷が大きいが他室の負荷が下がっている場合でも圧縮機容量（周波数）をアップし、負荷の大きい部屋が設定温度に達する時間を速くして快適性の向上を図ることができる。
【００４２】
実施の形態２．
本実施の形態にかかる多室形空気調和装置の冷凍サイクル図も、図４に示される従来例と同じである。また、圧縮機周波数制御の流れを示すブロック図、室内温度Ｔｒと設定温度Ｔｓとの差温△Ｔの温度ゾーン分割図は実施の形態１と同様である。実施の形態１との違いは、表９に示すように前記αｉの加算を、運転中の各室内機の温度ゾーンの最大値が所定時間Ｔmaxα以上一定の高いゾーンＺmaxα以上を連続した場合、Ｚmaxα未満のゾーンに低下するまで加算の回数ｎに上限を設けて所定時間Ｔmaxαごとに繰り返す点にある。
【表９】

【００４３】
実施の形態１と同様に表８の場合で説明すると、表５、表６より、室内機２１ａ、２１ｂ、２１ｃの能力負荷係数はＨ_２１ａ＝２２×１．００＝２２．０、Ｈ_２１ｂ＝２２×１．００＝２２．０、Ｈ_２１ｃ＝０であるから、ΣＨｎ＝４４．０であるが、室内機２１ａの温度ゾーンが８から７に低下すると、Ｈ_２１ａ＝１８×１．００＝１８．０となり、ΣＨｎ＝４０．０となる。したがって、従来の制御では、室内機２１ｂは最大負荷が続いているにかかわらず圧縮機周波数が低下する。
【００４４】
しかしながら、本実施の形態においては、温度ゾーン８以上が３分以上継続している室内機が１台でもあれば、能力供給中の全室内機の負荷定数にαｉ＝２を追加することを所定時間Ｔmaxα＝３分ごとにｎ＝４回まで繰り返すため、Ｈ_２１ａ＝（２２＋２）×１．００＝２４．０、Ｈ_２１ｂ＝（１８＋２）×１．００＝２０．０となり、ΣＨｎ＝２４．０＋２０．０＝４４．０となる。、さらに、Ｈ_２１ａ＝（２２＋２＋２）×１．００＝２６．０、Ｈ_２１ｂ＝（１８＋２＋２）×１．００＝２２．０となりΣＨｎ＝２６．０＋２２．０＝４８．０というように、所定周期毎に室内機２１ａ、２１ｂ、２１ｃのそれぞれの定格容量信号、差温信号、運転モード信号、ＯＮ―ＯＦＦ判別信号より演算を行い、各室内機の温度ゾーンの最大値が８未満に低下するまで能力供給中の全室内機の負荷定数にαｉを追加することを繰り返し圧縮機２２の周波数制御を行う。なお上記説明は、室内機２１ａの温度ゾーンが８から７に低下した場合であるが、温度ゾーン７からさらに低下した場合は圧縮機周波数がさらに低下するため、αｉの追加を繰り返すことによる効果はさらに大きくなる。
【００４５】
このように、ある室内の負荷が大きいが他室の負荷が下がり続けた場合でも、圧縮機容量（周波数）低下による負荷の大きい部屋の能力不足を防ぎ、負荷の大きい部屋が設定温度に達する時間をより速くし快適性の向上を図ることができる。
【００４６】
実施の形態３．
本実施の形態にかかる多室形空気調和装置の冷凍サイクル図も、図４に示される従来例と同じである。また、本実施の形態の圧縮機周波数制御の流れを示すブロック図、室内温度Ｔｒと設定温度Ｔｓとの差温△Ｔの温度ゾーン分割図は実施の形態１及び２と同様である。図３は温度ゾーンによる前記αｉ加算回数上限設定図である。実施の形態２との違いは、図３に示すように、温度ゾーンをＺmaxαを境にαｉ×ｎ加算領域とαｉ加算回数上限指定領域に分け、現在の温度ゾーンＺとαｉ×ｎ加算領域での加算回数Ｎによりαｉ加算回数上限値ｎｍａｘ＝Ｎ−（Ｚmaxα−Ｚ）を設定し、加算回数上限指定ゾーン（Ｚmaxα−Ｎ＋１≦温度ゾーン＜Ｚmaxα）で温度ゾーンが上昇した場合は現行加算回数を維持し、運転中の各室内機の温度ゾーンの最大値がＺmaxα以上になった場合現行の加算回数を維持し、連続Ｔmaxα（分）の間Ｚmaxα以上の場合に能力供給中の全室内機に更にαｉを追加している点である。
【００４７】
このような制御を行うことにより、各室内の温度ゾーンの最大値がある一定未満のゾーンに下がった場合に一気に加算された全てのαｉをクリアせず温度ゾーンが下がるとともに段階的にαｉをクリアすることができ圧縮機容量（周波数）の急低下による空調のハンチングを防ぐことができ快適性の向上を図ることができる。
【００４８】
実施の形態４．
本実施の形態にかかる多室形空気調和装置の冷凍サイクル図も、図４に示される従来例と同じである。また、本実施の形態の圧縮機周波数制御の流れを示すブロック図、室内温度Ｔｒと設定温度Ｔｓとの差温△Ｔの温度ゾーン分割図は実施の形態１乃至３と同様である。実施の形態１，２及び３との違いは、表１０に示すように、ある一定の低い温度ゾーンＺminα以下になった室内機に接続されている電動膨張弁３０の開度を膨張弁開度演算回路９により一定開度絞るようにした点にある。
【表１０】

【００４９】
このため、ある室内の負荷が大きいが他室の負荷が下がっている場合でも圧縮機容量（周波数）をアップするとともに、負荷の低下している室内機の電動膨張弁３０の開度を絞り低負荷室内機への能力供給をできるだけ抑え、負荷の大きい室内機への能力供給を増やすことができ、負荷の大きい部屋が設定温度に達する時間をより速くし快適性の向上を図ることができる。
【００５０】
なお、電動膨張弁３０の開度制御は、上述した従来制御と同じであり、図１に示される弁初期開度テーブル１１は図５の弁初期開度テーブル５１と同じものである。
【００５１】
実施の形態５．
本実施の形態にかかる多室形空気調和装置の冷凍サイクル図も、図４に示される従来例と同じである。また、本実施の形態の圧縮機周波数制御の流れを示すブロック図、室内温度Ｔｒと設定温度Ｔｓとの差温△Ｔの温度ゾーン分割図は実施の形態１乃至４と同様である。本実施の形態と実施の形態１乃至４との違いは以下の点である。
【００５２】
暖房運転時においては運転ＯＦＦ機の電動膨張弁３０を冷媒の溜まり込みを防止するため全閉せず微小開度に保ち冷媒を流している。
【表１１】

【００５３】
そのため、表１１を例にとり説明すると、室内機２１ｂは運転中であるが温度ゾーンが０のため、設定温度に達したと判断し能力供給は停止中（室内ファン停止で膨張弁開度微小）である。能力供給停止中は定期的に室内ファンを回して室温サンプリング（室内温度センサ３６ｂにより室内温度検出を行い、差温演算回路２により温度ゾーンを判定）を行っている。
【００５４】
従来、暖房時は運転ＯＦＦ機にも冷媒が流れているため、室温サンプリング中に室内ファンを回すと放熱され、能力供給中の室内機の放熱量が低下し能力が不足する問題があったが、本実施の形態においては、運転中の各室内の温度ゾーンの最大値が前記所定時間Ｔmaxα以上前記一定の高いゾーンＺmaxα以上を連続した場合に、能力供給中の全室内機と能力供給停止中で室温サンプリング中の負荷定数に一定値αｉを加算するとともに、室温サンプリング終了後能力供給停止中については前記αｉの加算を解除するようにしている。
【００５５】
このように、室温サンプリング中の室内機で放熱される能力分を加算しているため、室温サンプリング中に負荷の大きい部屋の能力を低下することなく負荷の大きい部屋が設定温度に達する時間をより速くし快適性の向上を図ることができる。
【００５６】
【発明の効果】
本発明は、以上説明したように構成されているので、以下に記載されるような効果を奏する。
本発明の多室形空気調和機によれば、運転中の各室内の温度ゾーンの最大値が所定時間以上所定のゾーン以上を連続した場合に、能力供給中の全室内機の負荷定数に所定値αｉを加算し、このαｉを加算した負荷定数に基づいて容量可変圧縮機の容量を制御するようにしたので、ある室内の負荷が大きいが他室の負荷が下がっている場合でも圧縮機容量（周波数）をアップし、負荷の大きい部屋が設定温度に達する時間を速くし快適性の向上を図ることができる。
【００５７】
また、αｉの加算回数に上限値を設定し、αｉを加算した負荷定数に基づく容量可変圧縮機の容量制御を、運転中の各室内の温度ゾ−ンの最大値が所定ゾーン未満のゾーンに低下するまでαｉの加算を所定時間ごとに繰り返して行うようにすると、ある室内の負荷が大きいが他室の負荷が下がり続けた場合でも圧縮機容量低下による負荷の大きい部屋の能力不足を防ぎ、負荷の大きい部屋が設定温度に達する時間をより速くし快適性の向上を図ることができる。
【００５８】
さらに、αｉの加算回数の上限値を各室内の温度ゾーンの最大値のゾーンにより設定し、加算回数上限指定ゾーンで温度ゾーンが上昇した場合、現行のαｉ加算回数を維持するようにすると、各室内の温度ゾーンの最大値がある一定未満のゾーンに下がった場合に一気に加算された全てのαｉをクリアせず温度ゾーンが下がるとともに、段階的にαｉをクリアすることができ圧縮機容量の急低下による空調のハンチングを防ぐことができ快適性の向上を図ることができる。
【００５９】
また、所定時間以上所定温度ゾーン以下の温度ゾーンを連続した室内機については、液側分岐管に取り付けられた電動膨張弁の開度を絞るようにすれば、ある室内の負荷が大きいが他室の負荷が下がっている場合でも、圧縮機容量がアップし、負荷の低下している室内機への能力の供給をできるだけ抑える一方、負荷の大きい室内機への能力供給を増やすことができ、負荷の大きい部屋が設定温度に達する時間をより速くし快適性の向上を図ることができる。
【００６０】
また、暖房運転時においては、能力供給停止中で室温サンプリング中の室内機にもαｉの加算を行い、室温サンプリング終了後αｉの加算を解除するようにすれば、室温サンプリング中の室内機で放熱される能力分を加算しているため、負荷の大きい部屋の設定温度への遅延を防止することができ、快適性の向上を図ることができる。
【図面の簡単な説明】
【図１】本発明の実施の形態１にかかる多室形空気調和装置における圧縮機周波数及び電動膨張弁開度の制御を示すブロック図である。
【図２】室内設定温度と検出温度との差温に基づく温度ゾーン分割図であり、（ａ）は冷房時のものを、（ｂ）は暖房時のものをそれぞれ示している。
【図３】本発明の実施の形態３にかかる多室形空気調和装置における各温度ゾーン毎の負荷定数への加算値の加算回数上限設定図である。
【図４】本発明にかかる多室形空気調和装置の冷凍サイクル図である。
【図５】従来の多室形空気調和装置における圧縮機周波数及び電動膨張弁開度の制御を示すブロック図である。
【図６】従来の多室形空気調和装置における室内設定温度と検出温度との差温に基づく温度ゾーン分割図であり、（ａ）は冷房時のものを、（ｂ）は暖房時のものをそれぞれ示している。
【図７】暖房時における圧縮機周波数の変化と吸込及び吹き出し温度の変化を示すグラフであり、（ａ）は従来制御のものを、（ｂ）は本発明による制御のものをそれぞれ示している。
【符号の説明】
１室内温度検出回路
２差温演算回路
３設定判別回路
４ＯＮ―ＯＦＦ判別回路
５定格容量記憶回路
６信号送出回路
７信号受信回路
８圧縮機周波数演算回路
９膨張弁開度演算回路
１０負荷定数テーブル
１１弁初期開度テーブル
２０室外機
２１ａ，２１ｂ，２１ｃ室内機
２２周波数可変形圧縮機
２３室外熱交換器
２４四方弁
２５ａ，２５ｂ，２５ｃ室内熱交換器
２６液側主管
２７ａ，２７ｂ，２７ｃ液側分岐管
２８ガス側主管
２９ａ，２９ｂ，２９ｃガス側分岐管
３０ａ，３０ｂ，３０ｃ電動膨張弁
３１レシーバ
３２，３５補助絞り
３３吸入管
３４バイパス管
３６ａ，３６ｂ，３６ｃ室内温度センサ
３７ａ，３７ｂ，３７ｃ運転設定回路
４０定格容量テーブル[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multi-room air conditioner in which a plurality of indoor units are connected to one outdoor unit, and the capacity is controlled by compressor capacity (frequency) control, and a control method thereof.
[0002]
[Prior art]
Conventionally, in a multi-room air conditioner in which a plurality of indoor units are connected to a single outdoor unit, a variable capacity compressor is used to control the refrigerant flow rate to each indoor unit in the liquid refrigerant piping of the refrigeration cycle. A refrigerant flow control valve is provided, and if the capacity of the outdoor unit is sufficient in the presence of the maximum load indoor unit according to the required load from the room, the capacity margin is supplied to the maximum load indoor unit. In this manner, a compressor for controlling the compressor capacity has been proposed (for example, JP-A-9-145130).
[0003]
The conventional multi-room air conditioner will be described below with reference to the drawings. FIG. 4 is a refrigeration cycle diagram of a conventional multi-chamber air conditioner. This multi-room air conditioner is configured by connecting a plurality of (three in FIG. 4)

indoor units

21a, 21b, and 21c to one outdoor unit 20. In the outdoor unit 20, there are provided an inverter-driven variable frequency compressor 22 (hereinafter simply referred to as a compressor), an outdoor heat exchanger 23, and a four-way valve 24 for switching between air conditioning and heating, while

indoor units

21a, 21b, 21c. Inside,

indoor heat exchangers

25a, 25b, and 25c are provided, respectively. The outdoor unit 20 and the

indoor units

21 a, 21 b, and 21 c are from liquid

side branch pipes

27 a, 27 b, 27 c branched from the liquid side main pipe 26 provided in the outdoor unit 20 and a gas side main pipe 28 provided in the outdoor unit 20. The branched gas

side branch pipes

29a, 29b, and 29c are connected. The liquid

side branch pipes

27a, 27b, and 27c are respectively provided with

electric expansion valves

30a, 30b, and 30c capable of electrically controlling the valve opening degree, and the refrigerant liquid can be stored on the liquid side main pipe 26. A receiver 31 is provided, and an auxiliary throttle 32 is provided to keep the receiver 31 at an intermediate pressure for both heating and cooling.
[0004]
Further, a bypass circuit 34 connecting the receiver 31 and the suction pipe 33 to the compressor 22 is provided, and an auxiliary throttle 35 is provided in the bypass circuit 34. Each

indoor unit

21a, 21b, 21c has

indoor temperature sensors

36a, 36b, 36c for detecting the room temperature of the room in which each

indoor unit

21a, 21b, 21c is installed, and an operation mode (cooling or heating) desired by the resident. Operation setting

circuits

37a, 37b, and 37c that can set the room temperature, operation and stop are provided.
[0005]
In the refrigeration cycle, during cooling, the refrigerant discharged from the compressor 22 flows from the four-way valve 24 to the outdoor heat exchanger 23 where it is heat-exchanged with the outdoor air to be condensed and liquefied and decompressed by the auxiliary throttle 32. Intermediate pressure. Then, a part of the liquid refrigerant is stored in the receiver 31, and the rest branches to the liquid

side branch pipes

27a, 27b, and 27c. Since the valve opening degree of the

electric expansion valves

30a, 30b, and 30c is controlled to be an opening degree corresponding to the load of each room by a control method to be described later, the refrigerant also has a low pressure at a flow rate corresponding to each load. After flowing into the

indoor heat exchangers

25a, 25b, and 25c and evaporating, the gas

side branch pipes

29a, 29b, and 29c pass through the gas side main pipe 28 and the four-way valve 24 and are again sucked into the compressor 22. Further, a very small amount of liquid refrigerant flows from the receiver 31 to the bypass circuit 34, is decompressed by the auxiliary throttle 35, and flows to the suction pipe 33. The compressor frequency is determined by a control method described later according to the total load.
[0006]
On the other hand, the four-way valve 24 is switched during heating, and the refrigerant discharged from the compressor 22 branches from the gas side main pipe 28 to the gas

side branch pipes

29a, 29b, 29c, and the

indoor heat exchangers

25a, 25b, 25c. And is condensed and liquefied, and is depressurized by the

electric expansion valves

30a, 30b, and 30c on the liquid

side branch pipes

27a, 27b, and 27c to become an intermediate pressure. Since the opening degrees of the

electric expansion valves

30a, 30b, and 30c are controlled to the opening degree corresponding to the load of each room by the control method described later in the same manner as at the time of cooling, the indoor heat exchanger at a flow rate corresponding to the refrigerant. It flows through 25a, 25b, and 25c. The refrigerant that has reached the intermediate pressure is partially stored in the receiver 31, and the rest is reduced in pressure by the auxiliary throttle 32, becomes low pressure, evaporates through the outdoor heat exchanger 23, and then passes through the four-way valve 24. Then, it is sucked into the compressor 22 again. Further, a very small amount of liquid refrigerant flows from the receiver 31 to the bypass circuit 34, is decompressed by the auxiliary throttle 35, and flows to the suction pipe 33. The compressor frequency is determined by a control method which will be described later according to the total load as in the case of cooling.
[0007]
FIG. 5 is a block diagram showing a flow of control of the compressor frequency and the electric expansion valve opening degree in the conventional example, and FIG. 6 is a temperature zone division diagram of the difference temperature ΔT between the indoor temperature Tr and the set temperature Ts in the conventional example. It is.
[0008]
First, in the indoor unit 21a, the output of the indoor temperature sensor 36a is sent from the indoor temperature detection circuit 41 to the differential temperature calculation circuit 42 as a temperature signal Tr, and the set temperature set in the operation setting circuit 37a by the setting determination circuit 43. Ts and the operation mode are discriminated and sent to the differential temperature calculation circuit 42. The differential temperature calculation circuit 42 calculates the differential temperature ΔT (= Tr−Ts) and converts it into a load number Ln value shown in FIG. For example, if Tr = 29.3 ° C. and Ts = 26 ° C. during the cooling operation, the air conditioning load maximum zone Ln = 8 at the temperature difference ΔT = 3.3 ° C. Further, the ON-OFF discriminating circuit 44 discriminates the operation (ON) or stop (OFF) of the indoor unit 21a set by the operation setting circuit 37a, and the rated capacity of the indoor unit 21a is set in the rated capacity storage circuit 45. The rated capacity signal, the differential temperature signal, the operation mode signal, and the ON / OFF discrimination signal are sent from the signal sending circuit 46 to the signal receiving circuit 47 of the outdoor unit 20. Similar signals are also sent from the

indoor units

21b and 21c to the signal receiving circuit 47. The signal received by the signal receiving circuit 47 is sent to the compressor frequency calculation circuit 48 and the expansion valve opening calculation circuit 49. However, when there are different operation mode signals, the operation mode of the indoor unit that started operation first is given priority, and the indoor unit in the different operation mode is considered to be stopped, and the ON-OFF determination circuit 44 is always OFF. Send a signal.
[0009]
The compressor frequency calculation circuit 48 reads the load constants from the load constant table 50 shown in Table 1 from the rated capacity signals, differential temperature signals, operation mode signals, and ON-OFF discrimination signals of the

indoor units

21a, 21b, and 21c. The frequency of the compressor 22 is determined by multiplying the sum of the load constants by the constant.
[Table 1]

[0010]
As an example, the case where the signals from the

indoor units

21a, 21b, and 21c are as shown in Table 2 at the start of operation during cooling will be described.
[Table 2]

[0011]
From Tables 1 and 2, the load constants of the

indoor units

21a, 21b, and 21c are 2.4, 3.0, and 0, respectively. Therefore, the frequency Hz of the compressor 22 is Hz = A × (2 .4 + 3.0 + 0) = A × 5.4. If the allowable operation value of the compressor 22 is a total value of 7.7 of 2.0, 2.5, and 3.2 corresponding to the rated capacity of the

indoor units

21a, 21b, and 21c, the frequency calculation result is the compressor 22 The operation allowable value is not reached and a margin of about 30% remains, and this calculation result is sent as a frequency signal to a compressor drive circuit (not shown) to control the frequency of the compressor 22. . Thereafter, calculation is performed from the rated capacity signal, the differential temperature signal, the operation mode signal, and the ON / OFF discrimination signal of each of the

indoor units

21a, 21b, and 21c at predetermined intervals, and both of the operating indoor units are set to Ln = 7. The above-described frequency is continued until the calculation result is reached, and the calculation result is sent as a frequency signal to a compressor drive circuit (not shown) to control the frequency of the compressor 22.
[0012]
Next, the case where the indoor unit 21c is started to operate while the

indoor units

21a and 21b are operating at a low load as shown in Table 3 will be described.
[Table 3]

[0013]
From Tables 1 and 2, the load constants of the

indoor units

21a, 21b, and 21c are 0.8, 1.0, and 3.8, respectively. Therefore, the frequency Hz of the compressor 22 is similarly Hz = A × (0. 8 + 1.0 + 3.8) = A × 5.6, and the frequency calculation result does not reach the allowable operation value of the compressor 22, leaving a margin of about 30%. This calculation result is used as a frequency signal. The signal is sent to a compressor drive circuit (not shown) to control the frequency of the compressor 22. Thereafter, calculation is performed from the rated capacity signal, the differential temperature signal, the operation mode signal, and the ON / OFF discrimination signal of each of the

indoor units

21a, 21b, and 21c at predetermined intervals, and the loads on the

indoor units

21a and 21b are the same. The frequency is continued until the indoor unit 21c reaches Ln = 7, and the calculation result is sent as a frequency signal to a compressor drive circuit (not shown) to control the frequency of the compressor 22. When the load of the

indoor units

21a and 21b is Ln = 7, Hz = A × (2.0 + 2.5 + 3.8) = A × 8.3, which exceeds the allowable operation value of the compressor 22, A frequency signal corresponding to the operation allowable value Hz = 7.7 of the compressor 22 is sent to the compressor drive circuit to control the frequency of the compressor 22.
[0014]
Similarly, in the expansion valve opening calculation circuit 49, load constants from the load constant table 50 shown in Table 1 are obtained from the rated capacity signals, differential temperature signals, operation mode signals, and ON-OFF discrimination signals of the

indoor units

21a, 21b, and 21c. Is read out from the valve initial opening degree table 51 for each rated capacity shown in Table 4 from the rated capacity of each of the

indoor units

21a, 21b, and 21c. Note that the initial valve opening is determined so that each indoor unit can perform a predetermined capacity control even in a combination of indoor units having different rated capacities.
[Table 4]

[0015]
The valve openings of the

electric expansion valves

30a, 30b, and 30c are obtained by multiplying each load constant by a predetermined value of the load constant and multiplying the initial valve opening. As in the case of the compressor frequency calculation example, the case where the signals from the

indoor units

21a, 21b, and 1c are shown in Table 2 will be described first.
[0016]
The (load constant / predetermined load constant) of the

indoor units

21a, 21b, and 21c are (2.4 / 2.0), (3.0 / 2.5), and (0 / 3.2), respectively. Since the opening degrees are 100, 130, and 180, respectively, the valve opening degrees of the

electric expansion valves

30a, 30b, and 30c are 120, 156, and 0, respectively. The calculation result is sent to an expansion valve drive circuit (not shown) as an expansion valve opening signal. Thereafter, the valve openings of the

electric expansion valves

30a, 30b, and 30c are calculated from the differential temperature signal, the operation mode signal, and the ON-OFF discrimination signal at predetermined intervals, and the expansion valve opening signal is used as the calculation result. It is sent to a drive circuit (not shown).
[0017]
Next, the case of Table 3 will be described. As in the case of Table 2, the (load constant / predetermined load constant) of the

indoor units

21a, 21b, and 21c are (0.8 / 2.0), (1.0 / 2.5), and (3.8), respectively. /3.2), and the initial valve openings are 100, 130, and 180, respectively, and the valve openings of the

electric expansion valves

30a, 30b, and 30c are 40, 52, and 214 (the first decimal place). Rounded off). The calculation result is sent to an expansion valve drive circuit (not shown) as an expansion valve opening signal. Thereafter, the valve openings of the

electric expansion valves

30a, 30b, and 30c are calculated from the differential temperature signal, the operation mode signal, and the ON-OFF discrimination signal at predetermined intervals, and the expansion valve opening signal is used as the calculation result. It is sent to a drive circuit (not shown).
[0018]
In this way, for indoor units with a low load, the capacity corresponding to the load is supplied, and only the indoor units in the air conditioning load maximum zone are targeted for the capacity exceeding the rated capacity of the indoor unit. Since the compressor frequency is controlled so as to supply the capacity, the time required to reach the set temperature can be shortened, and the comfort can be improved and the energy can be saved.
[0019]
[Problems to be solved by the invention]
However, the conventional multi-room air conditioner has the following problems. That is, for example, when the load of the indoor unit 21a decreases after the indoor unit 21b starts operating at the maximum load while the differential temperature signal of the indoor unit 21a is operating at Ln = 6 in the cooling operation, the load of the indoor unit 21b is reduced. Although the capacity is desired at the maximum, the compressor capacity (frequency) decreases as the load of the indoor unit 21a decreases, and it takes a long time for the indoor unit 21b to reach the set temperature.
[0020]
FIG. 7 (a) is a diagram showing changes in compressor frequency, suction, and blowing temperature during heating according to the conventional control method. The suction and blowing temperature on the high load side has not risen and the load remains high but the load on the low load side remains high. It can be seen that the frequency decreases due to the load decrease. In other words, even if a large amount of refrigerant is distributed to the indoor unit 21b side where the capacity is desired by the opening degree of the expansion valve, the dependence on the indoor unit capacity is dominated by the compressor capacity (frequency), so the load on a certain indoor unit is reduced. In this case, the capacity (frequency) of the compressor is reduced, and not only the room where the load is reduced, but also the capacity of other indoor units that require the maximum capacity is also reduced.
[0021]
The present invention has been made in view of such problems of the prior art, and increases the capacity (frequency) of the compressor even when the load in a certain room is large but the load in the other room is reduced. An object of the present invention is to provide a multi-room air conditioner with improved comfort and a control method thereof that can shorten the time required for a large room to reach a set temperature.
[0022]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a multi-room air in which one outdoor unit having a variable capacity compressor and an outdoor heat exchanger and a plurality of indoor units having an indoor heat exchanger are connected to each other. It is a conditioner, an indoor temperature setting means for arbitrarily setting the temperature of the room in which each indoor unit is installed, an indoor temperature detection means for detecting the indoor temperature, a temperature set by the indoor temperature setting means, Differential temperature calculation means for calculating the temperature difference from the indoor temperature detected by the indoor temperature detection means, capacity determination means for determining the rated capacity of each indoor unit, and whether each indoor unit is in operation or stopped On-off determination means and a load for storing a load constant set corresponding to the indoor load for each temperature zone of the plurality of temperature zones and the rated capacity of each indoor unit divided from the temperature range that the differential temperature can take Constant storage means and the temperature difference calculator A capacity calculating means for calculating the capacity of the compressor at predetermined intervals according to the number of operating units using data obtained from the capacity determining means, the on / off determining means and the load constant storing means, Based on the load constant obtained by adding the predetermined value αi to the load constant of all indoor units that are supplying the capacity and the maximum value of the temperature zones in each room for a predetermined time or longer for a predetermined time or longer. And controlling the capacity of the variable capacity compressor.
[0023]
Further, an upper limit value is set for the number of times αi is added, and the capacity control of the variable capacity compressor based on the load constant obtained by adding αi, the maximum value of the temperature zone in each room during operation is less than a predetermined zone It is also possible to repeat the addition of αi every predetermined time until it falls to the zone.
[0024]
Furthermore, the upper limit value of the number of additions of αi is set by the zone of the maximum value of the temperature zone in each room, and when the temperature zone rises in the addition number upper limit designation zone, the current number of additions of αi may be maintained. Good.
[0025]
Preferably, the outdoor unit and the plurality of indoor units are provided in the outdoor unit, a liquid side branch pipe branched from a liquid side main pipe through which a refrigerant liquid mainly flows, and a refrigerant gas mainly provided in the outdoor unit. Connected via a gas side branch pipe branched from the flowing gas side main pipe, and an electric expansion valve capable of electrically controlling the valve opening degree is attached to the liquid side branch pipe, and a temperature zone of a predetermined temperature zone and below a predetermined temperature zone Is set so that the opening degree of the electric expansion valve is reduced.
[0026]
In addition, during heating operation, the αi may be added to the indoor units whose capacity supply is stopped and sampling at room temperature, and the addition of αi may be canceled after the completion of the room temperature sampling.
[0027]
Furthermore, the present invention provides a control method for a multi-room air conditioner in which one outdoor unit having a variable capacity compressor and an outdoor heat exchanger and a plurality of indoor units having an indoor heat exchanger are connected to each other. In addition to setting a plurality of temperature zones according to the difference between the set temperature and the detected temperature of the room where each indoor unit is installed, a load constant corresponding to the indoor load is set for each temperature zone, The capacity of the variable capacity compressor is calculated based on the number of indoor units operated and the load constant of each indoor unit, and the capacity is being supplied when the maximum value of the temperature zone in each room continues for a predetermined time or longer. A predetermined value αi is added to the load constants of all indoor units, and the capacity of the variable capacity compressor is controlled based on the load constant obtained by adding the αi.
[0028]
In this case, an electric expansion valve capable of electrically controlling the valve opening degree is attached to a liquid side branch pipe that is provided in the outdoor unit and branched from a liquid side main pipe through which a refrigerant liquid mainly flows, and is at a predetermined temperature zone and below a predetermined temperature zone. For an indoor unit having a continuous temperature zone, it is preferable to reduce the opening of the electric expansion valve.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0030]
Embodiment 1 FIG.
The refrigeration cycle diagram of the multi-room air conditioner according to the present embodiment is the same as the conventional example shown in FIG. 4, and also in the present embodiment, one outdoor unit 20 includes three outdoor units 21a. , 21b, 21c will be described.
[0031]
FIG. 1 is a block diagram showing the flow of control of the compressor frequency, and FIG. 2 is a temperature zone division diagram of the temperature difference ΔT between the room temperature Tr and the set temperature Ts.
[0032]
First, in the indoor unit 21a, the output of the indoor temperature sensor 36a is sent as a temperature signal from the indoor temperature detection circuit 1 to the differential temperature calculation circuit 2, and the set temperature set by the operation setting circuit 37a in the setting determination circuit 3 and The operation mode is determined and sent to the differential temperature calculation circuit 2. The differential temperature calculation circuit 2 calculates a differential temperature ΔT (= Tr−Ts), converts it into a temperature zone value shown in FIG. 2, and uses it as a differential temperature signal. For example, if Tr = 29.3 ° C. and Ts = 26 ° C. during the cooling operation, the temperature zone Ln = 9 at the temperature difference ΔT = 3.3 ° C. Further, the ON-OFF discriminating circuit 4 discriminates the operation (ON) or stop (OFF) of the indoor unit 21a set by the operation setting circuit 37a, and the rated capacity of the indoor unit 21a is set in the rated capacity storage circuit 5. The rated capacity signal, the differential temperature signal, the operation mode signal, and the ON-OFF discrimination signal are sent from the signal sending circuit 6 to the signal receiving circuit 7 of the outdoor unit 20. A similar signal is also sent from the

indoor units

21 b and 21 c to the signal receiving circuit 7 of the outdoor unit 7. The signal received by the signal receiving circuit 7 is sent to the compressor frequency calculation circuit 8 and the expansion valve opening calculation circuit 9. However, when there are different operation mode signals, the operation mode of the indoor unit that has started operation is given priority, and the indoor unit in the different operation mode is considered to be stopped, and the ON-OFF determination circuit 4 is always OFF. Send a signal.
[0033]
From the rated capacity signal, differential temperature signal, operation mode signal, and ON-OFF discrimination signal of the

indoor units

21a, 21b, 21c in the compressor frequency calculation circuit 8, the load constant table 10 shown in Table 5 and the rating shown in Table 6 are given. The load constant αn and the rated capacity constant Qn are read from the capacity table 40, and the capacity load constant Hn of each chamber is obtained from the following equation by the product of the load constant αn and the rated capacity constant Qn.
Hn = αn × Qn
[0034]
Further, as shown in the following equation, the sum ΣHn of capacity load constants of the respective chambers is obtained, and the frequency of the compressor 22 is determined by a linear equation of ΣHn.
ΣHn = (H _21a + H _21b + H _21c )
Compressor frequency = A x ΣHn + B (A and B are constants)
[0035]
[Table 5]

[Table 6]

[0036]
At this time, as shown in an example in Table 7, when the maximum value of the temperature zone in each room during operation is continuously higher than the high zone Zmaxα, which is constant for a predetermined time Tmaxα, a constant value is set for the load constants of all indoor units that are supplying capacity. Add αi. Therefore, the capacity load coefficient Hn of each room is
Hn = (αn + αi) × Qn
[Table 7]

[0037]
As an example, the case where the signals from the

indoor units

21a, 21b, and 21c during heating are shown in Table 8 will be described.
[Table 8]

[0038]
From Tables 5 and 6, the capacity load coefficient of the

indoor units

21a, 21b, and 21c is H. _21a = 22 × 1.00 = 22.0, H _21b = 22 × 1.00 = 22.0, H _21c Since = 0, ΣHn = 44.0, but when the temperature zone of the indoor unit 21a decreases from 8 to 7, _21a = 18 × 1.00 = 18.0, and ΣHn = 40.0. In this case, in the conventional control, the compressor frequency decreases in the indoor unit 21b even though the maximum load continues.
[0039]
However, in this embodiment, if there is even one indoor unit in which the temperature zone 8 or higher continues for 3 minutes or longer, αi = 3 is added to the load constant of all indoor units whose capacity is being supplied. _21a = (22 + 3) x 1.00 = 25.0, H _21b = (18 + 3) × 1.00 = 21.0, and ΣHn = 25.0 + 21.0 = 46.0. The calculation result is sent as a frequency signal to a compressor drive circuit (not shown) to control the frequency of the compressor 22. Thereafter, calculation is performed from the rated capacity signal, the differential temperature signal, the operation mode signal, and the ON-OFF discrimination signal of each

indoor unit

21a, 21b, and 21c at predetermined intervals, and the maximum value of the temperature zone of each indoor unit is less than 8. The frequency control of the compressor 22 is performed by adding αi to the load constants of all the indoor units that are supplying the capacity until the power decreases to.
[0040]
FIG. 7B is a diagram showing changes in frequency, suction, and blowing temperature during heating when the above control according to the present embodiment is performed. Even if the load on the low load side decreases, the load on the high load side remains unchanged. When it is high, it can be seen that the compressor capacity (frequency) is increased.
[0041]
Although the above description was mainly performed during heating, the same control can be performed during cooling. Further, by changing the constants of Tmaxα, Zmaxα, and αi shown in Table 7, the width of the compressor frequency control can be further expanded. In this way, even when the load in one room is large but the load in another room is low, the compressor capacity (frequency) is increased, and the time for the heavily loaded room to reach the set temperature is increased to improve comfort. Can be planned.
[0042]
Embodiment 2. FIG.
The refrigeration cycle diagram of the multi-chamber air conditioner according to the present embodiment is also the same as the conventional example shown in FIG. Further, the block diagram showing the flow of the compressor frequency control and the temperature zone division diagram of the temperature difference ΔT between the room temperature Tr and the set temperature Ts are the same as in the first embodiment. The difference from Embodiment 1 is that, as shown in Table 9, the addition of αi is performed when the maximum value of the temperature zone of each indoor unit in operation is continuously higher than the constant zone Zmaxα for a predetermined time Tmaxα or more. The upper limit is set for the number of additions n until the zone falls to a lower zone, and is repeated every predetermined time Tmaxα.
[Table 9]

[0043]
As in the case of Embodiment 1, the case of Table 8 will be described. From Tables 5 and 6, the capacity load coefficients of the

indoor units

21a, 21b, and 21c are H. _21a = 22 × 1.00 = 22.0, H _21b = 22 × 1.00 = 22.0, H _21c = 0, so ΣHn = 44.0, but when the temperature zone of the indoor unit 21a decreases from 8 to 7, _21a = 18 × 1.00 = 18.0, and ΣHn = 40.0. Therefore, in the conventional control, the compressor frequency decreases in the indoor unit 21b regardless of the maximum load continuing.
[0044]
However, in the present embodiment, if there is even one indoor unit in which the temperature zone 8 or higher continues for 3 minutes or longer, it is predetermined that αi = 2 is added to the load constant of all the indoor units whose capacity is being supplied. Since the time Tmaxα = repeated up to n = 4 times every 3 minutes, H _21a = (22 + 2) x 1.00 = 24.0, H _21b = (18 + 2) × 1.00 = 20.0, and ΣHn = 24.0 + 20.0 = 44.0. And H _21a = (22 + 2 + 2) × 1.00 = 26.0, H _21b = (18 + 2 + 2) × 1.00 = 22.0 and ΣHn = 26.0 + 22.0 = 48.0, so that the rated capacity signal, the differential temperature signal of each of the

indoor units

21a, 21b, 21c, Compressor that repeatedly calculates αi from the operation mode signal and ON-OFF discrimination signal, and adds αi to the load constants of all indoor units that are supplying capacity until the maximum value of the temperature zone of each indoor unit drops below 8. 22 frequency control is performed. The above explanation is for the case where the temperature zone of the indoor unit 21a is lowered from 8 to 7. However, when the temperature zone 7 is further lowered, the compressor frequency is further lowered. It gets bigger.
[0045]
In this way, even when the load in one room is large but the load in the other room continues to decrease, the lack of capacity of the heavily loaded room due to a decrease in compressor capacity (frequency) is prevented, and the time for the heavily loaded room to reach the set temperature Can be made faster and comfort can be improved.
[0046]
Embodiment 3 FIG.
The refrigeration cycle diagram of the multi-chamber air conditioner according to the present embodiment is also the same as the conventional example shown in FIG. Further, the block diagram showing the flow of the compressor frequency control of the present embodiment and the temperature zone division diagram of the temperature difference ΔT between the room temperature Tr and the set temperature Ts are the same as in the first and second embodiments. FIG. 3 is an upper limit setting diagram of the αi addition count according to the temperature zone. As shown in FIG. 3, the difference from the second embodiment is that the temperature zone is divided into an αi × n addition region and an αi addition number upper limit designation region with Zmaxα as a boundary, and the current temperature zone Z and αi × n addition region are divided. Αi addition number upper limit value nmax = N- (Zmaxα-Z) is set by the number of additions N, and if the temperature zone rises in the addition number upper limit designation zone (Zmaxα-N + 1 ≦ temperature zone <Zmaxα), the current addition number is set. If the maximum value of the temperature zone of each indoor unit in operation is greater than or equal to Zmaxα, the current number of additions will be maintained, and if it is greater than or equal to Zmaxα for continuous Tmaxα (minutes), all indoor units that are supplying capacity will be maintained Further, αi is added.
[0047]
By performing such control, when the maximum value of the temperature zone in each room falls to a zone below a certain level, not all αi added at once are cleared, but the temperature zone falls and αi is cleared step by step Therefore, it is possible to prevent air-conditioning hunting due to a sudden decrease in compressor capacity (frequency), and to improve comfort.
[0048]
Embodiment 4 FIG.
The refrigeration cycle diagram of the multi-chamber air conditioner according to the present embodiment is also the same as the conventional example shown in FIG. Further, the block diagram showing the flow of the compressor frequency control of the present embodiment and the temperature zone division diagram of the temperature difference ΔT between the room temperature Tr and the set temperature Ts are the same as in the first to third embodiments. As shown in Table 10, the difference between the first, second, and third embodiments is that the opening degree of the electric expansion valve 30 connected to the indoor unit that is equal to or lower than a certain low temperature zone Zminα is the opening degree of the expansion valve. The arithmetic circuit 9 is designed to reduce the opening degree by a certain amount.
[Table 10]

[0049]
Therefore, even when the load in a certain room is large but the load in the other room is reduced, the compressor capacity (frequency) is increased and the opening of the electric expansion valve 30 of the indoor unit where the load is reduced is reduced. The capacity supply to the load indoor unit can be suppressed as much as possible, the capacity supply to the indoor unit with a large load can be increased, and the time for the room with a large load to reach the set temperature can be made faster and the comfort can be improved.
[0050]
The opening control of the electric expansion valve 30 is the same as the conventional control described above, and the valve initial opening table 11 shown in FIG. 1 is the same as the valve initial opening table 51 shown in FIG.
[0051]
Embodiment 5. FIG.
The refrigeration cycle diagram of the multi-chamber air conditioner according to the present embodiment is also the same as the conventional example shown in FIG. Further, the block diagram showing the flow of the compressor frequency control of the present embodiment and the temperature zone division diagram of the temperature difference ΔT between the room temperature Tr and the set temperature Ts are the same as in the first to fourth embodiments. The difference between the present embodiment and the first to fourth embodiments is as follows.
[0052]
During the heating operation, the electric expansion valve 30 of the operation-off machine is not fully closed in order to prevent the refrigerant from accumulating, and is kept at a very small opening to allow the refrigerant to flow.
[Table 11]

[0053]
For this reason, taking Table 11 as an example, the indoor unit 21b is in operation but the temperature zone is 0, so it is determined that the set temperature has been reached and the supply of capacity is stopped (expansion valve opening is very small when the indoor fan is stopped). It is. While the supply of capacity is stopped, the indoor fan is periodically rotated to perform room temperature sampling (the room temperature is detected by the room temperature sensor 36b and the temperature zone is determined by the differential temperature calculation circuit 2).
[0054]
Conventionally, since the refrigerant also flows to the operation OFF machine during heating, there is a problem that heat is dissipated when the indoor fan is turned during the room temperature sampling, and the heat dissipation of the indoor unit that is supplying the capacity is reduced, resulting in insufficient capacity. In the present embodiment, when the maximum value of the temperature zone in each room during operation continues for the predetermined time Tmaxα or more and the predetermined high zone Zmaxα or more, all the indoor units that are supplying the capacity and the capacity supply are stopped. Thus, the constant value αi is added to the load constant during the room temperature sampling, and the addition of αi is canceled when the capacity supply is stopped after the completion of the room temperature sampling.
[0055]
In this way, because the amount of heat dissipated by the indoor unit during room temperature sampling is added, the time for a room with a heavy load to reach the set temperature without degrading the capacity of the room with a heavy load during room temperature sampling is further increased. Faster and more comfortable.
[0056]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
According to the multi-room air conditioner of the present invention, when the maximum value of the temperature zone in each room during operation continues for a predetermined time or more for a predetermined zone or more, the load constant of all indoor units for which capacity is being supplied is predetermined. Since the value αi is added and the capacity of the variable capacity compressor is controlled based on the load constant obtained by adding this αi, the compressor capacity is increased even when the load in one room is large but the load in the other room is reduced. (Frequency) can be increased, and the time for a room with a large load to reach the set temperature can be shortened to improve comfort.
[0057]
In addition, an upper limit is set for the number of times αi is added, and the capacity control of the capacity variable compressor based on the load constant obtained by adding αi is set to a zone where the maximum value of the temperature zone in each operating room is less than the predetermined zone. By repeatedly adding αi every predetermined time until it decreases, even if the load in one room is large but the load in other rooms continues to decrease, it prevents the capacity shortage of the room with a large load due to the compressor capacity reduction, It is possible to improve the comfort by increasing the time required for a room with a large load to reach the set temperature.
[0058]
Furthermore, when the upper limit value of the number of additions of αi is set by the zone of the maximum value of the temperature zone in each room, and the temperature zone rises in the addition number upper limit designation zone, the current αi addition number is maintained, When the maximum value of the indoor temperature zone falls to a zone below a certain level, not all αi added at once are cleared, but the temperature zone goes down and αi can be cleared step by step, resulting in a sudden increase in compressor capacity. Air conditioning hunting due to lowering can be prevented, and comfort can be improved.
[0059]
In addition, for indoor units that continue a temperature zone that is longer than a predetermined time and lower than or equal to a predetermined temperature zone, if the opening of the electric expansion valve attached to the liquid side branch pipe is reduced, Even if the load of the compressor is reduced, the capacity of the compressor is increased and the supply of capacity to the indoor unit with a reduced load is suppressed as much as possible, while the capacity supply to the indoor unit with a heavy load can be increased. It is possible to improve the comfort by increasing the time required for the room having a large size to reach the set temperature.
[0060]
In addition, during heating operation, αi is also added to indoor units that have been stopped at room temperature sampling, and the addition of αi is canceled after the completion of room temperature sampling. Since the amount of capacity to be added is added, it is possible to prevent delay to the set temperature of a room with a large load, and to improve comfort.
[Brief description of the drawings]
FIG. 1 is a block diagram showing control of a compressor frequency and an electric expansion valve opening degree in a multi-chamber air conditioner according to Embodiment 1 of the present invention.
FIGS. 2A and 2B are temperature zone division diagrams based on a temperature difference between an indoor set temperature and a detected temperature. FIG. 2A shows a cooling time, and FIG. 2B shows a heating time.
FIG. 3 is an upper limit setting diagram of the number of additions to the load constant for each temperature zone in the multi-room air conditioner according to the third embodiment of the present invention.
FIG. 4 is a refrigeration cycle diagram of a multi-chamber air conditioner according to the present invention.
FIG. 5 is a block diagram showing control of a compressor frequency and an electric expansion valve opening degree in a conventional multi-chamber air conditioner.
FIGS. 6A and 6B are temperature zone division diagrams based on a temperature difference between a set indoor temperature and a detected temperature in a conventional multi-room air conditioner, where FIG. 6A is for cooling and FIG. 6B is for heating. Respectively.
FIGS. 7A and 7B are graphs showing a change in compressor frequency and a change in suction and blowing temperature during heating, where FIG. 7A shows a conventional control, and FIG. 7B shows a control according to the present invention. .
[Explanation of symbols]
1 Indoor temperature detection circuit
2 Differential temperature calculation circuit
3 Setting discrimination circuit
4 ON-OFF discrimination circuit
5 Rated capacity memory circuit
6 Signal transmission circuit
7 Signal receiving circuit
8 Compressor frequency calculation circuit
9 Expansion valve opening calculation circuit
10 Load constant table
11 Valve initial opening table
20 Outdoor unit
21a, 21b, 21c indoor unit
22 Frequency variable compressor
23 Outdoor heat exchanger
24 Four way valve
25a, 25b, 25c Indoor heat exchanger
26 Liquid side main pipe
27a, 27b, 27c Liquid side branch pipe
28 Gas side main pipe
29a, 29b, 29c Gas side branch pipe
30a, 30b, 30c Electric expansion valve
31 receiver
32, 35 Auxiliary aperture
33 Suction tube
34 Bypass pipe
36a, 36b, 36c Indoor temperature sensor
37a, 37b, 37c Operation setting circuit
40 Rated capacity table

Claims

A multi-room air conditioner in which one outdoor unit having a variable capacity compressor and an outdoor heat exchanger and a plurality of indoor units having an indoor heat exchanger are connected to each other,
An indoor temperature setting means for arbitrarily setting the temperature of the room where each indoor unit is installed, an indoor temperature detection means for detecting the indoor temperature, a temperature set by the indoor temperature setting means, and a detection by the indoor temperature detection means A temperature difference calculating means for calculating a temperature difference from the indoor temperature, a capacity determining means for determining the rated capacity of each indoor unit, an on / off determining means for determining whether each indoor unit is operating or stopped, and Load constant storage means for storing a load constant set corresponding to the indoor load for each temperature zone of each of the plurality of temperature zones and for each rated capacity of each indoor unit that divides the temperature range that the differential temperature can take; and Capacity calculation means for calculating the capacity of the compressor at predetermined intervals according to the number of operating units using data obtained from the differential temperature calculation means, the capacity determination means, the on / off determination means, and the load constant storage means. Preparation A load obtained by adding a predetermined value αi to the load constant of all indoor units that are supplying capacity, and adding the αi when the maximum value of the temperature zone in each room during operation continues for a predetermined time or longer for a predetermined time or longer. While controlling the capacity of the variable capacity compressor based on a constant, an upper limit value is set to the number of additions of the αi, and the capacity control of the variable capacity compressor based on the load constant obtained by adding the αi The multi-room air conditioner characterized in that the addition of αi is repeated every predetermined time until the maximum value of the temperature zone in each room decreases to a zone below a predetermined zone .

The upper limit of the number of additions of the αi is set by the zone of the maximum value of the temperature zone of each chamber, when the temperature zone rises with the number of additions limit specified zone, claims and maintains the current αi number of additions Item 4. The multi-chamber air conditioner according to Item 1 .

The outdoor unit and the plurality of indoor units are provided in the outdoor unit, a liquid side branch pipe branched from a liquid side main pipe through which refrigerant liquid mainly flows, and a gas side provided in the outdoor unit and through which refrigerant gas mainly flows. Connected via a gas-side branch pipe branched from the main pipe, and an electric expansion valve capable of electrically controlling the valve opening degree was attached to the liquid-side branch pipe, and a temperature zone of a predetermined temperature zone and lower than a predetermined temperature zone was continued. The multi-room air conditioner according to claim 1 or 2, wherein the opening of the electric expansion valve is reduced for the indoor unit.

In the heating operation, in the indoor unit in the room temperature samples in capacity outages performs addition of the .alpha.i, any one of claims 1 to 3, characterized in that to release the addition of the room temperature samples after the end the .alpha.i The multi-chamber air conditioner according to claim 1.

A control method of a multi-room air conditioner in which one outdoor unit having a variable capacity compressor and an outdoor heat exchanger and a plurality of indoor units having an indoor heat exchanger are connected to each other,
Set multiple temperature zones according to the temperature difference between the set temperature and the detected temperature in the room where each indoor unit is installed, and set the load constant corresponding to the indoor load for each temperature zone.
Calculate the capacity of the variable capacity compressor based on the number of indoor units operated and the load constant of each indoor unit,
When the maximum value of the temperature zones in each room continues for a predetermined time or more and a predetermined zone or more, a predetermined value αi is added to the load constants of all indoor units that are supplying capacity, and based on the load constant obtained by adding the αi The capacity of the variable capacity compressor is controlled, an upper limit is set for the number of times αi is added, and the capacity control of the capacity variable compressor based on the load constant obtained by adding αi The control method for a multi-room air conditioner is characterized in that the addition of αi is repeated at predetermined time intervals until the maximum value of − is decreased to a zone less than the predetermined zone .