JPH052902B2 - - Google Patents

Description

【発明の詳細な説明】[Detailed description of the invention]

（産業上の利用分野） 本発明は、運転容量を可変にする圧縮機を備え
た冷凍装置において、冷媒循環量に応じて電動膨
張弁の開度を制御するものに関する。 （従来の技術） 容量可変の圧縮機を備えた冷凍装置において、
従来より圧縮機の容量に応じて冷媒の減圧機構で
ある電動膨張弁の開度を大小制御するものが知ら
れている。 例えば、特開昭58−205057号公報に開示される
ごとく、運転周波数により圧縮機の容量を可変に
駆動するインバータを備え、室内負荷に応じてイ
ンバータの出力周波数を制御し、同時に該インバ
ータの出力周波数に応じて電動膨張弁の開度を固
定値に設定して、制御の応答性を高めるようにし
たものがある。 一方、例えば特開昭56−105272号公報に開示さ
れる如く、冷媒の凝縮圧力と蒸発能力との圧力差
に応じて減圧機構の減圧度を可変に調節する手段
を設けることにより、負荷の変動の大きい場合で
も適正な過冷却度を保持しようとするものは公知
の技術である。 （発明が解決しようとする問題点） しかしながら、上記前者の公報のものでは、電
動膨張弁の開度が単に圧縮機の容量に応じた固定
値に制御されるため、冷媒の状態の変化、例えば
蒸発温度や凝縮温度の変化に即応できず、冷媒の
過熱運転あるいは湿り運転となる状態が生じ、電
動膨張弁を常に適切な開度に制御できないという
問題がある。 一方、上記後者の公報のものでは、凝縮圧力と
蒸発圧力との差圧に応じて減圧度を変化させるた
め、圧縮機の容量が固定される装置では所定の効
果を得られるものの、圧縮機の容量が変化すると
所定の効果を得られない虞れが生じる。すなわ
ち、同じ圧力差でも圧縮機の容量が異なると冷媒
の循環量が変わつてくるからである。 本発明は斯かる点に鑑みてなされたものであ
り、その目的は、圧縮機の容量変化に対して、蒸
発温度と凝縮温度とをパラメータとする異なる適
正開度計算式に基づいて電動膨張弁の開度を制御
することにより、過熱運転あるいは湿り運転を防
止することにある。 （問題点を解決するための手段） 上記目的を達成するため、本発明の解決手段
は、第１図に示すように、容量可変の圧縮機１、
凝縮器１２、冷媒の減圧作用を行う電動膨張弁
８、および蒸発器６を順次接続した冷凍サイクル
を備えた冷凍装置を対象とする。そして、上記蒸
発器６における冷媒の蒸発温度を検出する蒸発温
度検出手段TH５と、上記凝縮器１２における冷
媒の凝縮温度を検出する凝縮温度検出手段Ｐ１と
を設ける。さらに、上記圧縮機１の容量毎に、冷
媒の蒸発温度および凝縮温度をパラメータとし
て、容量で定まる冷媒循環量に適合するよう設定
された電動膨張弁８の適正開度計算式を記憶する
記憶手段５０と、上記蒸発温度検出手段TH５お
よび凝縮温度検出手段Ｐ１の信号を受け、これら
の信号と圧縮機１の運転容量とに基づいて上記記
憶手段５０の適正開度計算式により電動膨張弁８
の適正開度を演算する演算手段５１と、該演算手
段５１の信号を受け、電動膨張弁８の開度を上記
適正開度になるように制御する制御手段５２とを
設ける構成としたものである。 （作用） 以上の構成により、本発明では、予め圧縮機１
の運転容量毎に、冷媒の蒸発温度および凝縮温度
とをパラメータとして、電動膨張弁８の適正開度
を計算する適正開度計算式が記憶手段５０に記憶
されている。そして、冷凍装置の運転中に各凝縮
器１２，…における冷凍負荷の変動等により圧縮
機１の運転容量が変化した時、変化後の運転容量
と、蒸発温度検出手段TH５により検出される蒸
発温度と、凝縮温度検出手段Ｐ１により検出され
る凝縮温度とに関する信号を受け、演算手段５１
により上記記憶手段５０の適正開度計算式に基づ
いて電動膨張弁８の適正開度が演算され、その演
算結果に応じて、制御手段５２により電動膨張弁
８の開度が上記適正開度に制御される。 すなわち、冷凍負荷の変動に応じて圧縮機１の
容量が変化すると、冷媒循環量が変わるため、凝
縮温度及び蒸発温度が同じでも適正な過熱度を与
える電動膨張弁８の開度も変化することになる
が、本発明では、電動膨張弁８の開度が圧縮機１
の容量に応じて変化する冷媒循環量に適合した適
正開度にオープンループ制御されるので、ハンチ
ングを生じることなく安定な制御で過熱度が適正
範囲に保持され、過熱運転及び湿り運転が防止さ
れることになる。 （実施例） 以下、本発明の実施例を第２図以下の図面に基
づき説明する。 第２図は本発明を適用したマルチ型空気調和装
置の冷媒配管系統を示し、Ａは室外ユニツト、Ｂ
〜Ｆが該室外ユニツトＡに並列に接続された室内
ユニツトである。上記室外ユニツトＡの内部に
は、出力周波数を30〜70Hzの範囲で10Hz毎に可変
に切換えられるインバータ２ａにより容量が調整
される第１圧縮機１ａと、パイロツト圧の高低で
差動するアンローダ２ｂにより容量がフルロード
（100％）およびアンロード（50％）状態の２段階
に調整される第２圧縮機１ｂとを逆止弁１ｅを介
して並列に接続して構成される圧縮機１と、該圧
縮機１から吐出されるガス中の油を分離する油分
離器４と、暖房運転時には図中実線の如く切換わ
り冷房運転時には図中破線の如く切換わる四路切
換弁５と、冷房運転時に凝縮器、暖房運転時に蒸
発器となる室外熱交換器６およびそのフアン６ａ
と、過冷却コイル７と、冷房運転時には冷媒流量
を調節し、暖房運転時には冷媒の絞り作用を行う
室外電動膨張弁８と、液化した冷媒を貯蔵するレ
シーバ９と、アキユムレータ１０とが主要機器と
して内蔵されていて、該各機器１〜１０は各々冷
媒の連絡配管１１で冷媒の流通可能に接続されて
いる。また上記室内ユニツトＢ〜Ｆは同一構成で
あり、各々、冷房運転時には蒸発器、暖房運転時
には凝縮器となる室内熱交換器１２…およびその
フアン１２ａ…を備え、かつ該室内熱交換器１２
…の液冷媒分岐管１１ａ…には、暖房運転時に冷
媒流量を調節し、冷房運転時に冷媒の絞り作用を
行う室内電動膨張弁１３…がそれぞれ介設されて
いて、該各室内ユニツトＢ〜Ｆは、各冷媒分岐管
１１ａ…を手動閉鎖弁１７を介設した連絡配管１
１ｂで並列に接続せしめて、室外ユニツトＡに冷
媒循環可能に接続されている。また、TH１…は
各室内温度を検出する室温サーモスタツト、TH
２…およびTH３…は各々室内熱交換器１２…の
液側およびガス側配管における冷媒の温度を検出
する温度センサ、TH４は圧縮機１の吐出管にお
ける冷媒の温度を検出する温度センサ、TH５は
暖房運転時に室外熱交換器６（蒸発器）における
蒸発温度を検出する蒸発温度検出手段としての温
度センサ、TH６は圧縮機１に吸入される吸入ガ
スの温度を検出する蒸発温度検出手段としての温
度センサ、Ｐ１は冷媒の凝縮温度を検出するため
に暖房運転時に吐出ガスの圧力を検知する凝縮温
度検出手段としての圧力センサである。 なお、第２図において上記各主要機器以外に補
助用の諸機器が設けられている。１ｆは第２圧縮
機１ｂのバイパス回路１１ｃに介設されて、第２
圧縮機１ｂの停止時およびアンロード状態時に
「開」となり、フルロード状態で「閉」となるア
ンローダ用電磁弁、１ｇはキヤピラリーチユー
ブ、１ｈおよび１ｉは油分離器４から油戻し配管
１１ｕを経て第１圧縮機１ａおよび第２圧縮機１
ｂに潤滑油を戻す分岐管１１ｖおよび１１ｗに介
設されて返油量をコントロールするキヤピラリー
チユーブ、２１は吐出管と吸入管とを接続する均
圧ホツトガスバイパス回路１１ｄに介設されて、
冷房運転時室内熱交換器１２（蒸発器）が低負荷
状態のときおよびデフロスト時等に開作動するホ
ツトガス用電磁弁である。また、１１ｅは暖房過
負荷制御用バイパス回路であつて、該バイパス回
路１１ｅには、補助コンデンサ２２、第１逆止弁
２３、暖房運転時室内熱交換器１２（凝縮器）が
低負荷時のとき開作動する高圧制御弁２４および
第２逆止弁２５が順次直列に接続されており、そ
の一部には運転停止時に液封を防止するための液
封防止バイパス回路１１ｆが第３逆止弁２７およ
びキヤピラリーチユーブCP３を介して設けられ
ている。さらに、１１ｇは上記暖房過負荷バイパ
ス回路１１ｅの液冷媒側配管と主配管の吸入ガス
管との間を接続し、冷暖房運転時に吸入ガスの過
熱度を調節するためのリキツドインジエクシヨン
バイパス回路であつて、該リキツドインジエクシ
ヨンバイパス回路１１ｇには圧縮機１のオン・オ
フと連動して開閉するインジエクシヨン用電磁弁
２９と、感温筒TP１により検出される吸入ガス
の過熱度に応じて開度を調節される自動膨張弁３
０とが介設されている。 また、第２図中、Ｆ１〜Ｆ６は冷媒回路あるい
は油戻し管中に介設された液浄化用フイルタ、
HPSは圧縮機保護用の高圧圧力開閉器、SPはサ
ービスポートである。 そして、上記各電磁弁およびセンサ類は各主要
機器と共に後述の室外制御ユニツト１５に信号線
で接続され、該室外制御ユニツト１５は各室内制
御ユニツト１６…に連絡配線によつて信号の授受
可能に接続されている。 第３図は上記室外ユニツトＡ側に配置される室
外制御ユニツト１５の内部および接続される各機
器の配線関係を示す電気回路図である。図中、
MC１はインバータ２ａの周波数変換回路INVに
接続された第１圧縮機１ａのモータ、MC２は第
２圧縮機１ｂのモータ、MFは室外フアン６ａの
モータ、５２Ｆ，５２Ｃ１および５２Ｃ２は各々
フアンモータMF、周波数変換回路INVおよびモ
ータMC２を作動させる電磁接触器で、上記各機
器はヒユーズボツクスFS、漏電ブレーカBR１を
介して三相交流電源に接続されるとともに、室外
制御ユニツト１５とは単相交流電源で接続されて
いる。次に、室外制御ユニツト１５の内部にあつ
ては、電磁リレーの常開接点RY１〜RY７が単
相交流電流に対して並列に接続され、これらは順
に、四路切換弁５の電磁リレー２０Ｓ、周波数変
換回路INVの電磁接触器５２Ｃ１、第２圧縮機
１ｂの電磁接触器５２Ｃ２、室外フアン用電磁接
触器５２Ｆ、アンローダ用電磁弁１ｆの電磁リレ
ーSVL、ホツトガス用電磁弁２１の電磁リレー
SVPおよびインジエクシヨン用電磁弁２９の電
磁リレーSVTのコイルに直列に接続され、室外
制御ユニツト１５に入力される室温サーモスタツ
トTH１および温度センサTH２〜TH６の信号
に応じて開閉されて、上記各電磁接触器あるいは
電磁リレーの接点を開閉させるものである。ま
た、端子CNには、室外電動膨張弁８の開度を調
節するパルスモータEVのコイルが接続されてい
る。なお、第３図右側の回路において、CH１，
CH２はそれぞれ第１圧縮機１ａ、第２圧縮機１
ｃのオイルフオーミング防止用ヒータで、それぞ
れ電磁接触器５２Ｃ１，５２Ｃ２と直列に接続さ
れ上記各圧縮機１ａ，１ｂが停止時に電流が流れ
るようになされている。さらに、５１Ｃ２はモー
タMC２の過電流リレー、４９Ｃ１，４９Ｃ２は
それぞれ第１圧縮機１ａ、第２圧縮機１ｂの温度
上昇保護用スイツチ、６３Ｈ１，６３Ｈ２はそれ
ぞれ第１圧縮機１ａ、第２圧縮機１ｂの圧力上昇
保護用スイツチ、５１ＦはフアンモータMFの過
電流リレーであつて、これらは直列に接続されて
起動時には電磁リレー３０Fxをオン状態にし、
故障にはオフ状態にさせる保護回路を構成してい
る。そして、室外制御ユニツト１５には破線で示
される室外制御装置１５ａが内蔵され、該室外制
御装置１５ａによつて各室内制御ユニツト１６…
あるいは各センサ類から入力される信号に応じて
各機器の動作が制御される。 次に、第４図は室内制御ユニツト１６の内部お
よび接続される各機器の主な配線を示す電気回路
図である。第４図で、MFは室内フアン１２ａの
モータで、単相交流電源を受けて各リレー端子
RY１〜RY３によつて風量を強風と弱風とに切
換え、暖房運転時室温サーモスタツトTH１の信
号による停止時のみ微風にするようになされてい
る。そして、室内制御ユニツト１５のプリント基
板の端子CNには室内電動膨張弁１３の開度を調
節するパルスモータEVが接続される一方、室温
サーモスタツトTH１および温度センサーTH２，
TH３の信号が入力されている。また、各室内制
御ユニツト１６は室外制御ユニツト１５に信号線
を介して信号の授受可能に接続されるとともに、
リモートコントロールスイツチRCSからは入力
可能に接続されている。そして、室内制御ユニツ
ト１６には破線で示される室内制御装置１６ａが
内蔵され、該室内制御装置１６ａによつて、各セ
ンサ類あるいは室外制御ユニツト１５からの信号
に応じて室内電動膨張弁１３あるいは室内フアン
１２ａの動作が制御される。 第２図において、空気調和装置の暖房運転時、
冷媒はガス状態で圧縮機１により圧縮され、四路
切換弁５を経て各室内ユニツトＢ〜Ｆに分岐して
送られる。各室内ユニツトＢ〜Ｆでは、各室内熱
交換器１２…で熱交換を受けて凝縮された後合流
し、室外ユニツトＡで、レシーバ９に液貯蔵さ
れ、液状態で室外電動膨張弁８によつて絞り作用
を受けて室外熱交換器６で蒸発し、ガス状態とな
つて圧縮機１に戻る。 以上の冷媒の流れの暖房運転時において、室内
ユニツトＢ〜Ｆではその室内の空調負荷に応じて
調整される各室内電動膨張弁１３…開度が制御さ
れ、全体の冷媒流量の各室内ユニツトＢ〜Ｆへの
分配流量が下記手順により決定される。 第５図は、室温サーモスタツトTH１の設定値
（Ts）と吸込空気温度（Ta）との偏差（Ta−
Ta）と室内電動膨張弁１３の目標開度ARとの関
係を示すグラフであつて、ここに（Amax）は最
大開度、（Amin）は閉じる場合の最小制御開度、
Aoは全閉を示す。したがつて、偏差値（Ts−
Ta）が増大すると目標開度もリニアに増大する
ようになされている。 そして、室内制御ユニツト１６は室温サーモス
タツトTH１の信号を受けて、所定のサンプリン
グ時間ごとに目標開度ARを演算して現在の開度
Ａと比較し、室内電動膨張弁１３の開度をAR＜
Ａのときには所定パルスずつ閉じ、AR＞Ａのと
きには所定パルスずつ開く開度変更信号を出力す
る。このように、室内電動膨張弁１６の開度Ａが
変更されて各開度に応じて冷媒流量が分配され
る。 次に、室外ユニツトＡでは、各室内熱交換器１
２…（凝縮器）における冷媒の凝縮温度の平均値
Tcを一定に保持するために圧縮機１の容量制御
が行われる。 尚、凝縮温度Tcの制御目標値Tcsが室外制御
ユニツト１５内部のスイツチにより、Ｈ，Ｍ，Ｌ
（Ｈ：Tcs＝48℃、Ｍ：Tcs＝46℃，Ｌ：Tcs＝44
℃）の３通りに切換可能にしている。 まず、圧力センサＰ１により凝縮温度の平均値
Tcが検知されると、制御目標値Tcsとの差に応
じて下式により圧縮機１の運転周波数（容量）の
変更量ΔFkを求める。 ΔFk＝Kc［｛ｅ（ｔ）−ｅ（ｔ−Δt）｝ ＋（Δt／2Ti）｛ｅ（ｔ） ＋ｅ（ｔ−Δt）｝］ …(1) ここで、Kcはゲイン、ｅ（ｔ）は時刻ｔにおけ
る実側凝縮温度Tcと制御目標値tcsとの偏差値す
なわち、Te（ｔ）−Tcs（ｔ）、ｅ（ｔ−Δt）は同様
にサンプリング開始前の偏差値、Δtはサンプリ
ング時間、Tiは積分時間である。 そして、以上のように算出されたΔFkの値と
変更前の運転周波数Fkとの和に応じて、例えば
10Hzきざみで圧縮機１の運転容量が変更される。 ここで、第２圧縮機１ｂの運転容量は、フルロ
ード時で60Hz、アンロード時で30Hzとなるので、
第１圧縮機１ａのインバータ２ａの10Hzきざみの
容量変化と組み合わせることにより、合計０〜
130Hzの範囲で10Hzきざみに調節され得るもので
ある。 以上の手順により圧縮機１の運転周波数（容
量）が定められると、その運転容量に応じて室外
制御ユニツト１５ａにより室外電動膨張弁８の開
度制御が行われる。以下にその手順を説明する。 第６図は、室外制御ユニツト１５に内蔵される
室外制御装置１５ａの信号伝達経路図である。第
６図において、４０は室外制御ユニツト１５の第
１圧縮機１ａ、及び第２圧縮機１ｂの運転容量を
検出するサンプリング回路、４１および４２はそ
れぞれ、第１圧縮機１ａおよび第２圧縮機１ｃの
容量に応じた室外電動膨張弁の開度を演算する後
述の開度計算式を予め記憶する第１記憶回路およ
び第２記憶回路、４３および４４はそれぞれ該第
１記憶回路４１および第２記憶回路４２の記憶内
容に基づき、蒸発温度Teおよび凝縮温度Tcの値
に応じて室外電動膨張弁８の開度を演算する第１
演算回路および第２演算回路、４５は該第１演算
回路４３および第２演算回路４４の演算結果を加
算する加算回路、４６は上記加算回路４５の信号
と室外電動膨張弁８のパルスモータEVの回転位
置から得られる現在の開度とを比較して、新開度
に変更するための信号を出力する比較回路、４７
は該比較回路４６の信号に応じてパルス信号を発
生するパルス発生回路である。 次に、第６図における信号の伝達経路を説明す
るにあたつて、上記第１記憶回路４１、第２記憶
回路４２に予め設定される室外電動膨張弁１５の
開度計算式を決定する手順を説明する。 第７図は、インバータ１ｂの出力周波数に応じ
た第１圧縮機１ａの運転容量、アンローダのフル
ロード、およびアンロード状態に応じた第２圧縮
機１ｂの運転容量に対して第７図温度センサTH
５により検出される冷媒の蒸発温度に対する圧縮
機１の容量一定時の流量特性の例を示すような蒸
発温度Teの上昇に対し冷媒循環量が増大する特
性曲線が圧力センサＰ１により検出される凝縮温
度Tcをパラメータとして求められる。一方、冷
媒流量と電動膨張弁の開度の間には、一般に電動
膨張弁の一定の差圧に対して第８図に示すように
開度の増大に対し冷媒流量がほぼリニアに増大す
る関係がある。したがつて、上記の関係より、第
１圧縮機１ａ、および第２圧縮機１ｂの各運転容
量に応じて、室外電動膨張弁８の開度Ａが蒸発温
度Te、凝縮温度Tcの計算式として求められる。
例えば、 Ａ＝K1・Te・Tc＋K2・Te＋K3・ Tc＋K4 …(2) と近似して、第７図および第８図の関係より数
値計算すれば、各定数K1〜K4が求められる。そ
の値の例を下記第１表に示す。 (Industrial Application Field) The present invention relates to a refrigeration system equipped with a compressor whose operating capacity is variable, in which the opening degree of an electric expansion valve is controlled according to the amount of refrigerant circulation. (Prior art) In a refrigeration system equipped with a variable capacity compressor,
2. Description of the Related Art Conventionally, it has been known to control the opening degree of an electric expansion valve, which is a refrigerant pressure reduction mechanism, in accordance with the capacity of a compressor. For example, as disclosed in Japanese Unexamined Patent Publication No. 58-205057, an inverter is provided that variably drives the capacity of a compressor depending on the operating frequency, and the output frequency of the inverter is controlled according to the indoor load, and at the same time the output of the inverter is There is one in which the opening degree of the electric expansion valve is set to a fixed value depending on the frequency to improve control responsiveness. On the other hand, as disclosed in JP-A-56-105272, for example, by providing means for variably adjusting the degree of pressure reduction of the pressure reduction mechanism according to the pressure difference between the condensation pressure and the evaporation capacity of the refrigerant, it is possible to It is a known technique to maintain an appropriate degree of supercooling even when the temperature is large. (Problem to be Solved by the Invention) However, in the former publication, the opening degree of the electric expansion valve is simply controlled to a fixed value according to the capacity of the compressor, so changes in the state of the refrigerant, e.g. There is a problem in that the refrigerant cannot immediately respond to changes in the evaporation temperature or condensation temperature, resulting in overheating or wet operation of the refrigerant, and the electric expansion valve cannot always be controlled to an appropriate opening degree. On the other hand, in the latter publication, the degree of pressure reduction is changed according to the differential pressure between the condensing pressure and the evaporation pressure, so although a certain effect can be obtained in a device where the capacity of the compressor is fixed, If the capacitance changes, there is a risk that the desired effect may not be obtained. That is, even if the pressure difference is the same, if the capacity of the compressor differs, the amount of refrigerant circulated will change. The present invention has been made in view of the above, and its purpose is to provide an electric expansion valve based on different appropriate opening calculation formulas using evaporation temperature and condensation temperature as parameters in response to changes in compressor capacity. The purpose is to prevent overheating or wet operation by controlling the opening degree of the valve. (Means for solving the problem) In order to achieve the above object, the solving means of the present invention includes a variable capacity compressor 1, as shown in FIG.
The object is a refrigeration system equipped with a refrigeration cycle in which a condenser 12, an electric expansion valve 8 that reduces the pressure of refrigerant, and an evaporator 6 are sequentially connected. An evaporation temperature detection means TH5 for detecting the evaporation temperature of the refrigerant in the evaporator 6 and a condensation temperature detection means P1 for detecting the condensation temperature of the refrigerant in the condenser 12 are provided. Further, storage means stores, for each capacity of the compressor 1, a formula for calculating the appropriate opening of the electric expansion valve 8, which is set to match the refrigerant circulation amount determined by the capacity, using the evaporation temperature and condensation temperature of the refrigerant as parameters. 50, the evaporating temperature detecting means TH5 and the condensing temperature detecting means P1, and based on these signals and the operating capacity of the compressor 1, the electric expansion valve 8 is determined by the appropriate opening calculation formula of the storing means 50.
A calculation means 51 for calculating the appropriate opening degree of the electric expansion valve 8, and a control means 52 for receiving the signal from the calculation means 51 and controlling the opening degree of the electric expansion valve 8 to the above-mentioned appropriate opening degree. be. (Function) With the above configuration, in the present invention, the compressor 1
An appropriate opening degree calculation formula for calculating the appropriate opening degree of the electric expansion valve 8 is stored in the storage means 50 for each operating capacity of the refrigerant, using the evaporation temperature and condensation temperature of the refrigerant as parameters. When the operating capacity of the compressor 1 changes due to changes in the refrigeration load in each condenser 12, etc. during operation of the refrigeration system, the operating capacity after the change and the evaporation temperature detected by the evaporation temperature detection means TH5 are determined. and the condensation temperature detected by the condensation temperature detection means P1, the calculation means 51
The appropriate opening degree of the electric expansion valve 8 is calculated based on the appropriate opening degree calculation formula in the storage means 50, and according to the calculation result, the opening degree of the electric expansion valve 8 is adjusted to the above-mentioned appropriate opening degree by the control means 52. controlled. In other words, when the capacity of the compressor 1 changes in response to fluctuations in the refrigeration load, the amount of refrigerant circulation changes, so even if the condensing temperature and evaporation temperature are the same, the opening degree of the electric expansion valve 8 that provides the appropriate degree of superheating also changes. However, in the present invention, the opening degree of the electric expansion valve 8 is the same as that of the compressor 1.
Open-loop control is performed to the appropriate opening degree that matches the refrigerant circulation amount, which changes depending on the capacity of the refrigerant, so the degree of superheating is maintained within the appropriate range with stable control without causing hunting, and overheating and wet operation are prevented. That will happen. (Example) Hereinafter, an example of the present invention will be described based on the drawings from FIG. 2 onwards. Figure 2 shows the refrigerant piping system of a multi-type air conditioner to which the present invention is applied, where A is the outdoor unit and B is the outdoor unit.
-F are indoor units connected in parallel to the outdoor unit A. Inside the outdoor unit A, there is a first compressor 1a whose capacity is adjusted by an inverter 2a whose output frequency is variably switched in 10Hz increments in the range of 30 to 70Hz, and an unloader 2b which operates differentially depending on the pilot pressure. The compressor 1 is configured by connecting in parallel via a check valve 1e a second compressor 1b whose capacity is adjusted in two stages: full load (100%) and unload (50%). , an oil separator 4 that separates oil from the gas discharged from the compressor 1; a four-way switching valve 5 that switches as shown by the solid line in the figure during heating operation and as shown by the broken line in the figure during cooling operation; The outdoor heat exchanger 6 and its fan 6a serve as a condenser during operation and an evaporator during heating operation.
The main equipment includes a subcooling coil 7, an outdoor electric expansion valve 8 that adjusts the refrigerant flow rate during cooling operation and throttles the refrigerant during heating operation, a receiver 9 that stores liquefied refrigerant, and an accumulator 10. Each of the devices 1 to 10 is connected through a refrigerant communication pipe 11 so that refrigerant can flow therein. In addition, the indoor units B to F have the same configuration, and are each equipped with an indoor heat exchanger 12 that serves as an evaporator during cooling operation and a condenser during heating operation, and its fans 12a...
The liquid refrigerant branch pipes 11a of... are respectively provided with indoor electric expansion valves 13 that adjust the refrigerant flow rate during heating operation and perform a throttling action on the refrigerant during cooling operation, and each of the indoor units B to F , each refrigerant branch pipe 11a... is connected to a connecting pipe 1 with a manual shutoff valve 17 interposed therebetween.
They are connected in parallel at 1b and connected to the outdoor unit A so that refrigerant can circulate there. In addition, TH1... is a room temperature thermostat that detects each room temperature, TH
2... and TH3... are temperature sensors that detect the temperature of the refrigerant in the liquid side and gas side piping of the indoor heat exchanger 12... respectively, TH4 is a temperature sensor that detects the temperature of the refrigerant in the discharge pipe of the compressor 1, and TH5 is a temperature sensor that detects the temperature of the refrigerant in the discharge pipe of the compressor 1. A temperature sensor serves as an evaporation temperature detection means to detect the evaporation temperature in the outdoor heat exchanger 6 (evaporator) during heating operation, and TH6 serves as an evaporation temperature detection means to detect the temperature of the suction gas taken into the compressor 1. A sensor P1 is a pressure sensor serving as a condensing temperature detecting means that detects the pressure of discharged gas during heating operation in order to detect the condensing temperature of the refrigerant. In addition, in FIG. 2, various auxiliary devices are provided in addition to the above-mentioned main devices. 1f is interposed in the bypass circuit 11c of the second compressor 1b, and the second
An unloader solenoid valve that opens when the compressor 1b is stopped and unloaded and closes when fully loaded; 1g is a capillary reach tube; 1h and 1i are oil return pipes 11u from the oil separator 4; The first compressor 1a and the second compressor 1
A capillary reach tube 21 is installed in the branch pipes 11v and 11w that return lubricating oil to control the amount of oil returned;
This is a hot gas electromagnetic valve that opens when the indoor heat exchanger 12 (evaporator) is in a low load state during cooling operation and during defrosting. Further, 11e is a heating overload control bypass circuit, and the bypass circuit 11e includes an auxiliary condenser 22, a first check valve 23, and an indoor heat exchanger 12 (condenser) during heating operation when the load is low. A high-pressure control valve 24 and a second check valve 25, which open when the operation is stopped, are connected in series, and part of them includes a liquid seal prevention bypass circuit 11f for preventing liquid seal when the operation is stopped. It is provided via a valve 27 and a capillary reach tube CP3. Furthermore, 11g is a liquid injector bypass circuit that connects between the liquid refrigerant side pipe of the heating overload bypass circuit 11e and the suction gas pipe of the main pipe, and adjusts the degree of superheat of the suction gas during heating and cooling operation. The liquid injection bypass circuit 11g includes an injection extraction solenoid valve 29 that opens and closes in conjunction with the on/off of the compressor 1, and a solenoid valve 29 that opens and closes in conjunction with the on/off of the compressor 1, and a solenoid valve 29 that responds to the degree of superheat of the intake gas detected by the temperature sensing tube TP1. Automatic expansion valve 3 whose opening degree is adjusted by
0 is interposed. In addition, in FIG. 2, F1 to F6 are liquid purification filters installed in the refrigerant circuit or oil return pipe,
HPS is a high pressure switch for compressor protection, and SP is a service port. The above-mentioned solenoid valves and sensors are connected to an outdoor control unit 15, which will be described later, by signal lines along with each main equipment, and the outdoor control unit 15 can send and receive signals to each indoor control unit 16 through connection wiring. It is connected. FIG. 3 is an electric circuit diagram showing the interior of the outdoor control unit 15 disposed on the outdoor unit A side and the wiring relationship of each connected device. In the diagram,
MC1 is the motor of the first compressor 1a connected to the frequency conversion circuit INV of the inverter 2a, MC2 is the motor of the second compressor 1b, MF is the motor of the outdoor fan 6a, 52F, 52C1 and 52C2 are each fan motor MF, This is an electromagnetic contactor that operates the frequency conversion circuit INV and motor MC2, and each of the above devices is connected to a three-phase AC power source via a fuse box FS and an earth leakage breaker BR1, and is connected to the outdoor control unit 15 by a single-phase AC power source. It is connected. Next, inside the outdoor control unit 15, the normally open contacts RY1 to RY7 of the electromagnetic relays are connected in parallel to the single-phase alternating current, and these are sequentially connected to the electromagnetic relay 20S of the four-way switching valve 5, Electromagnetic contactor 52C1 of frequency conversion circuit INV, electromagnetic contactor 52C2 of second compressor 1b, electromagnetic contactor 52F for outdoor fan, electromagnetic relay SVL of electromagnetic valve 1f for unloader, electromagnetic relay of electromagnetic valve 21 for hot gas.
The electromagnetic contacts mentioned above are connected in series to the coil of the electromagnetic relay SVT of the SVP and injection solenoid valve 29, and are opened and closed in response to signals from the room temperature thermostat TH1 and temperature sensors TH2 to TH6 input to the outdoor control unit 15. It opens and closes the contacts of a device or an electromagnetic relay. Further, a coil of a pulse motor EV that adjusts the opening degree of the outdoor electric expansion valve 8 is connected to the terminal CN. In addition, in the circuit on the right side of Figure 3, CH1,
CH2 is the first compressor 1a and the second compressor 1, respectively.
The oil forming prevention heater c is connected in series with the electromagnetic contactors 52C1 and 52C2, respectively, so that current flows when the compressors 1a and 1b are stopped. Furthermore, 51C2 is an overcurrent relay for motor MC2, 49C1 and 49C2 are temperature rise protection switches for first compressor 1a and second compressor 1b, respectively, and 63H1 and 63H2 are for first compressor 1a and second compressor 1b, respectively. The pressure rise protection switch 51F is the overcurrent relay for the fan motor MF, and these are connected in series and turn on the electromagnetic relay 30Fx at startup.
It has a protection circuit that turns it off in the event of a failure. The outdoor control unit 15 includes an outdoor control device 15a shown by a broken line, and the outdoor control device 15a controls each indoor control unit 16...
Alternatively, the operation of each device is controlled according to signals input from each sensor. Next, FIG. 4 is an electrical circuit diagram showing the interior of the indoor control unit 16 and the main wiring of each connected device. In Fig. 4, MF is the motor of the indoor fan 12a, which receives single-phase AC power and connects to each relay terminal.
The air volume is switched between strong and weak winds using RY1 to RY3, and the light breeze is set only when the heating operation is stopped by a signal from the room temperature thermostat TH1. A pulse motor EV for adjusting the opening degree of the indoor electric expansion valve 13 is connected to the terminal CN of the printed circuit board of the indoor control unit 15, while a room temperature thermostat TH1, a temperature sensor TH2,
TH3 signal is input. Further, each indoor control unit 16 is connected to the outdoor control unit 15 via a signal line so that signals can be sent and received.
It is connected for input from the remote control switch RCS. The indoor control unit 16 has a built-in indoor control device 16a shown by a broken line, and the indoor electric expansion valve 13 or the indoor The operation of the fan 12a is controlled. In Figure 2, during heating operation of the air conditioner,
The refrigerant is compressed in a gas state by a compressor 1, and is branched and sent to each of the indoor units B to F via a four-way switching valve 5. In each of the indoor units B to F, the water undergoes heat exchange in each of the indoor heat exchangers 12 and is condensed, and then merges. In the outdoor unit A, the liquid is stored in the receiver 9, and in a liquid state is passed through the outdoor motorized expansion valve 8. It is then evaporated in the outdoor heat exchanger 6 under the throttling action and returned to the compressor 1 in a gas state. During the heating operation of the above refrigerant flow, the opening degree of each indoor electric expansion valve 13 is controlled according to the indoor air conditioning load in indoor units B to F, and the opening degree of each indoor electric expansion valve 13 is controlled depending on the overall refrigerant flow rate. The distribution flow rate to ~F is determined by the following procedure. Figure 5 shows the deviation (Ta-
This is a graph showing the relationship between Ta) and the target opening AR of the indoor electric expansion valve 13, where (Amax) is the maximum opening, (Amin) is the minimum control opening when closing,
Ao indicates fully closed. Therefore, the deviation value (Ts−
As Ta) increases, the target opening degree also increases linearly. Then, the indoor control unit 16 receives the signal from the room temperature thermostat TH1, calculates the target opening degree AR at every predetermined sampling time, compares it with the current opening degree A, and adjusts the opening degree of the indoor electric expansion valve 13 to AR. <
When AR>A, an opening degree change signal is output which closes the opening by a predetermined pulse and opens by a predetermined pulse when AR>A. In this way, the opening degree A of the indoor electric expansion valve 16 is changed, and the refrigerant flow rate is distributed according to each opening degree. Next, in outdoor unit A, each indoor heat exchanger 1
2. Average value of refrigerant condensation temperature in (condenser)
Capacity control of the compressor 1 is performed to keep Tc constant. The control target value Tcs of the condensing temperature Tc is set to H, M, L by a switch inside the outdoor control unit 15.
(H: Tcs=48℃, M: Tcs=46℃, L: Tcs=44
It can be switched in three ways (°C). First, the average value of the condensing temperature is determined by pressure sensor P1.
When Tc is detected, the amount of change ΔFk in the operating frequency (capacity) of the compressor 1 is determined by the following formula according to the difference from the control target value Tcs. ΔFk=Kc [{e(t)−e(t−Δt)} +(Δt/2Ti){e(t) +e(t−Δt)}] …(1) Here, Kc is the gain, e(t ) is the deviation value between the actual condensing temperature Tc and the control target value tcs at time t, that is, Te (t) - Tcs (t), e (t - Δt) is the deviation value before the start of sampling, and Δt is the sampling Time, Ti is the integration time. Then, depending on the sum of the value of ΔFk calculated as above and the operating frequency Fk before change, for example,
The operating capacity of compressor 1 is changed in 10Hz steps. Here, the operating capacity of the second compressor 1b is 60Hz when fully loaded and 30Hz when unloaded, so
By combining the capacity change in 10Hz steps of the inverter 2a of the first compressor 1a, the total
It can be adjusted in 10Hz increments within a range of 130Hz. When the operating frequency (capacity) of the compressor 1 is determined by the above procedure, the opening degree of the outdoor electric expansion valve 8 is controlled by the outdoor control unit 15a according to the operating capacity. The procedure will be explained below. FIG. 6 is a signal transmission path diagram of the outdoor control device 15a built in the outdoor control unit 15. In FIG. 6, 40 is a sampling circuit for detecting the operating capacities of the first compressor 1a and the second compressor 1b of the outdoor control unit 15, and 41 and 42 are the first compressor 1a and the second compressor 1c, respectively. A first memory circuit and a second memory circuit 43 and 44, which store in advance an opening degree calculation formula described below for calculating the opening degree of the outdoor electric expansion valve according to the capacity of the outdoor electric expansion valve, are the first memory circuit 41 and the second memory circuit, respectively. A first circuit that calculates the opening degree of the outdoor electric expansion valve 8 according to the values of the evaporation temperature Te and the condensation temperature Tc based on the memory contents of the circuit 42.
An arithmetic circuit and a second arithmetic circuit, 45 an adder circuit that adds the arithmetic results of the first arithmetic circuit 43 and the second arithmetic circuit 44, and 46 a signal of the adder circuit 45 and the pulse motor EV of the outdoor electric expansion valve 8; a comparison circuit that compares the current opening degree obtained from the rotational position and outputs a signal for changing to a new opening degree; 47;
is a pulse generation circuit that generates a pulse signal in response to the signal from the comparison circuit 46. Next, in explaining the signal transmission path in FIG. 6, the procedure for determining the opening degree calculation formula of the outdoor electric expansion valve 15, which is preset in the first storage circuit 41 and the second storage circuit 42, will be explained. Explain. FIG. 7 shows the temperature sensor in FIG. T.H.
A characteristic curve in which the amount of refrigerant circulation increases with respect to an increase in the evaporation temperature Te, which is an example of the flow rate characteristic when the capacity of the compressor 1 is constant with respect to the evaporation temperature of the refrigerant detected by the pressure sensor P1, is detected by the pressure sensor P1. It is determined using temperature Tc as a parameter. On the other hand, there is generally a relationship between the refrigerant flow rate and the opening degree of the electric expansion valve, as shown in Figure 8 for a certain differential pressure of the electric expansion valve, the refrigerant flow rate increases almost linearly as the opening degree increases. There is. Therefore, from the above relationship, the opening degree A of the outdoor electric expansion valve 8 can be calculated as the evaporation temperature Te and condensation temperature Tc according to the operating capacities of the first compressor 1a and the second compressor 1b. Desired.
For example, by approximating A=K1・Te・Tc+K2・Te+K3・Tc+K4 (2) and performing numerical calculations from the relationships shown in FIGS. 7 and 8, each of the constants K1 to K4 can be obtained. Examples of the values are shown in Table 1 below.

【表】【table】

【表】 上記第１表において、左端の番号は圧縮機の区
別を示し、「１」第１圧縮機１ａ，「２」は第２圧
縮機１ｃである。 第１圧縮機１ａおよび第２圧縮機１ｂの各運転
容量に対応して上記第１表の定数を用いた開度計
算式が、第６図の第１記憶回路４１および第２記
憶回路４２に予め記憶されている。 そして、第６図において、第１記憶回路４１、
第２記憶回路４２に設定された開度計算式に基づ
き第１演算回路４３、第２演算回路４４によつて
蒸発温度Te、凝縮温度Tcの値に応じて、第１圧
縮機１ａ、第２圧縮機１ｂの容量に対する室外電
動膨張弁８の開度A1，A2がそれぞれ演算され
る。例えば、第１圧縮機１ｂの運転容量が60Hz、
第２圧縮機１ｂの運転容量がフルロードのとき、 A1＝−0.346・Te・Tc＋24.6・ Te−7.08・Te＋540 A2＝−0.329・Te・Tc＋23.0・ Te−6.63・Tc＋504 で表される開度計算式に基づき演算が行われ
る。 次に、加算回路４５により上記演算結果が加算
され、合計の開度Ａ（＝A1＋A2）が算出された
後、比較回路４６により現在の開度と比較され
る。そして、現在の開度との偏差分だけ増分する
ための信号が出力されて、パルス発生回路４７に
よりパルス信号として出力され、パルスモータ
EVのステツプ数が変更されて室外電動膨張弁８
の開度が制御される。 上記第１記憶回路４１および第２記憶回路４２
により、圧縮機の運転容量毎に、蒸発温度Te、
凝縮温度Tcをパラメータとして、冷媒の循環量
に適合するよう設定された室外電動膨張弁１５の
適正開度計算式（上記(2)式）予め記憶する記憶手
段５０が構成され、第１演算回路４３、第２演算
回路４４、加算回路４５および比較回路４６によ
り、上記記憶手段５０の記憶内容に基づき適正開
度を演算する演算手段５１が構成されている。ま
た、パルス発生回路４７およびパルスモータEV
により、上記演算手段５１の演算結果に基づいて
室外電動膨張弁８の開度を適正開度になるように
制御する制御手段５２が構成されている。 上記構成により、例えば室内ユニツトＢ〜Ｆが
配置されている室内の負荷が増すと第５図に示す
ように室内電動膨張弁１３の開度が増大して平均
凝縮温度Tcが下降し、その変化に応じてTcを一
定に保持するように圧縮機１の運転容量が増大す
る。そして、増大した圧縮機１の運転容量、蒸発
温度および凝縮温度によつて定まる冷媒の循環量
に応じて室外電動膨張弁８の開度が修正される。
このように室内負荷変化後の制御状態において
Tcを一定に保持すべく圧縮機１の容量を変化さ
せる一方、そのときの圧縮機１の容量により定ま
る冷媒の流量に適合するよう室外電動膨張弁８の
開度が制御されるので、多数の室内熱交換器１２
…を配置したマルチ型空気調和装置のように広範
な範囲で冷凍負荷が変化し、それに応じて圧縮機
１の容量が変化する場合にも、室外熱交換器６に
おける冷媒の比体積が適正範囲に保持されて過熱
度がほぼ適正範囲に保持されるのである。室内負
荷が減少する場合にも同様にして過熱度がほぼ適
正範囲に保持される。 以上の制御では空調負荷の変化に応じて、系が
変化するべき正常な制御状態を予測して圧縮機１
の容量に対する室外電動膨張弁８の開度を制御す
るので、きわめて速く応答するものであり、単に
過熱度を検知して例えばPID制御等により電動膨
張弁の開度をフイードバツク制御するときに生ず
るような制御遅れによるハンチングは生じない。
また、上記開度の変更により蒸発温度Teあるい
は凝縮温度Tcが変化したときにもすぐに開度を
補正して過熱度を適正範囲に保持するので、圧縮
機１の運転容量に対し室外電動膨張弁８の開度を
固定する方法に比べ、過熱運転あるいは湿り運転
に入るのが有効に防止されている。また制御の構
成も比較的簡素である。 以上、本発明をマルチ型空気調和装置に適用し
た例について説明したが、本発明はかかる実施例
に限定されるものではなく、例えば一台の室内ユ
ニツトのみを備えたいわゆるセパレート型空気調
和装置や給湯装置等についても適用しうるもので
ある。 （発明の効果） 以上説明したように、本発明によれば、容量可
変の圧縮機、凝縮器、電動膨張弁及び蒸発器を順
次接続した冷凍サイクルを備えた冷凍装置におい
て、圧縮機の容量毎に冷媒の凝縮温度及び蒸発温
度をパラメータとして圧縮機の容量から定まる圧
縮機の冷媒流量に適合するように設定された電動
膨張弁の適正開度計算式を予め記憶しておき、そ
の適正開度計算式に基づいて電動膨張弁の開度を
制御するようにしたので、広範な冷凍負荷の変動
に対してもハンチングのない安定な制御で過熱運
転および湿り運転を有効に防止することができ
る。また、制御のための構成も比較適簡素に済
む。[Table] In Table 1 above, the numbers on the left end indicate the different compressors, and "1" is the first compressor 1a, and "2" is the second compressor 1c. Opening calculation formulas using the constants in Table 1 above are stored in the first storage circuit 41 and the second storage circuit 42 in FIG. It is stored in advance. In FIG. 6, the first memory circuit 41,
Based on the opening degree calculation formula set in the second storage circuit 42, the first arithmetic circuit 43 and the second arithmetic circuit 44 determine whether the first compressor 1a or the second compressor Opening degrees A1 and A2 of the outdoor electric expansion valve 8 with respect to the capacity of the compressor 1b are respectively calculated. For example, if the operating capacity of the first compressor 1b is 60Hz,
When the operating capacity of the second compressor 1b is at full load, it is expressed as A1=-0.346・Te・Tc+24.6・Te−7.08・Te+540 A2=−0.329・Te・Tc+23.0・Te−6.63・Tc+504 Calculations are performed based on the opening calculation formula. Next, the addition circuit 45 adds the above calculation results to calculate the total opening degree A (=A1+A2), which is then compared with the current opening degree by the comparison circuit 46. Then, a signal for incrementing by the deviation from the current opening degree is output, and the pulse generation circuit 47 outputs it as a pulse signal, and the pulse motor
The number of EV steps has been changed and outdoor electric expansion valve 8
The opening degree is controlled. The first memory circuit 41 and the second memory circuit 42
For each operating capacity of the compressor, the evaporation temperature Te,
A storage means 50 is configured to store in advance an appropriate opening degree calculation formula (formula (2) above) for the outdoor electric expansion valve 15 set to match the circulating amount of refrigerant using the condensing temperature Tc as a parameter, and the first calculation circuit 43, the second arithmetic circuit 44, the addition circuit 45, and the comparison circuit 46 constitute a calculation means 51 that calculates the appropriate opening degree based on the contents stored in the storage means 50. In addition, the pulse generation circuit 47 and the pulse motor EV
Thus, a control means 52 is configured which controls the opening degree of the outdoor electric expansion valve 8 to a proper opening degree based on the calculation result of the calculation means 51. With the above configuration, for example, when the load in the room where indoor units B to F are arranged increases, the opening degree of the indoor electric expansion valve 13 increases and the average condensing temperature Tc decreases, as shown in FIG. Accordingly, the operating capacity of the compressor 1 increases so as to keep Tc constant. Then, the opening degree of the outdoor electric expansion valve 8 is corrected in accordance with the refrigerant circulation amount determined by the increased operating capacity of the compressor 1, evaporation temperature, and condensation temperature.
In this way, in the control state after changing the indoor load,
While the capacity of the compressor 1 is changed to keep Tc constant, the opening degree of the outdoor electric expansion valve 8 is controlled to match the flow rate of refrigerant determined by the capacity of the compressor 1 at that time. Indoor heat exchanger 12
Even when the refrigerating load changes over a wide range and the capacity of the compressor 1 changes accordingly, as in a multi-type air conditioner equipped with..., the specific volume of the refrigerant in the outdoor heat exchanger 6 is within the appropriate range. The degree of superheat is maintained within an approximately appropriate range. Even when the indoor load decreases, the degree of superheat is maintained within an approximately appropriate range in the same manner. The above control predicts the normal control state in which the system should change in response to changes in the air conditioning load, and
Since it controls the opening degree of the outdoor electric expansion valve 8 with respect to the capacity of No hunting occurs due to control delay.
In addition, even when the evaporation temperature Te or condensation temperature Tc changes due to the above-mentioned change in the opening degree, the opening degree is immediately corrected to maintain the degree of superheat within the appropriate range. Compared to the method of fixing the opening degree of the valve 8, overheating or wet operation is effectively prevented. Furthermore, the control configuration is relatively simple. Although an example in which the present invention is applied to a multi-type air conditioner has been described above, the present invention is not limited to such an embodiment. It can also be applied to water heaters, etc. (Effects of the Invention) As explained above, according to the present invention, in a refrigeration system equipped with a refrigeration cycle in which a variable capacity compressor, a condenser, an electric expansion valve, and an evaporator are sequentially connected, each capacity of the compressor is A formula for calculating the appropriate opening of the electric expansion valve, which is set to match the refrigerant flow rate of the compressor determined from the capacity of the compressor using the refrigerant condensation temperature and evaporation temperature as parameters, is stored in advance, and the appropriate opening is calculated. Since the opening degree of the electric expansion valve is controlled based on a calculation formula, overheating operation and wet operation can be effectively prevented with stable control without hunting even over a wide range of refrigeration load fluctuations. Furthermore, the configuration for control is relatively simple.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は本発明の構成を示す冷媒系統図であ
る。第２図〜第８図は本発明の実施例を示し、第
２図はその冷媒系統図、第３図は室外制御ユニツ
トの電気回路図、第４図は室内制御ユニツトの電
気回路図、第５図は室温サーモスタツトの設定値
と吸込空気温度との偏差（Ts−Ta）と室内電動
膨張弁１３の開度との関係を示すグラフ、第６図
は室外制御装置の内部構成を示す信号伝達回路
図、第７図は蒸発温度Teと冷媒流量との関係を
示す圧縮機の特性線図、第８図は室外電動膨張弁
の開度と冷媒流量との関係を示す特性線図であ
る。 １……圧縮機、６……室外熱交換器（蒸発器）、
８……室外電動膨張弁、１２……室内熱交換器
（凝縮器）、５０……記憶手段、５１……演算手
段、５２……制御手段、TH５……温度センサ
（蒸発温度検出手段）、Ｐ１……圧力センサ（凝縮
温度検出手段）。 FIG. 1 is a refrigerant system diagram showing the configuration of the present invention. 2 to 8 show embodiments of the present invention, FIG. 2 is a refrigerant system diagram, FIG. 3 is an electric circuit diagram of the outdoor control unit, FIG. 4 is an electric circuit diagram of the indoor control unit, and FIG. Figure 5 is a graph showing the relationship between the deviation (Ts - Ta) between the set value of the room temperature thermostat and the intake air temperature and the opening degree of the indoor electric expansion valve 13, and Figure 6 is a graph showing the internal configuration of the outdoor control device. The transmission circuit diagram, Fig. 7 is a characteristic line diagram of the compressor showing the relationship between the evaporation temperature Te and the refrigerant flow rate, and Fig. 8 is a characteristic line diagram showing the relationship between the opening degree of the outdoor electric expansion valve and the refrigerant flow rate. . 1...Compressor, 6...Outdoor heat exchanger (evaporator),
8...Outdoor electric expansion valve, 12...Indoor heat exchanger (condenser), 50...Storage means, 51...Calculation means, 52...Control means, TH5...Temperature sensor (evaporation temperature detection means), P1...Pressure sensor (condensing temperature detection means).

Claims (1)

【特許請求の範囲】[Claims] １ 容量可変の圧縮機１、凝縮器１２、冷媒の減
圧作用を行う電動膨張弁８、および蒸発器６を順
次接続した冷凍サイクルを備えた冷凍装置におい
て、上記蒸発器６における冷媒の蒸発温度を検出
する蒸発温度検出手段TH５と、上記凝縮器１２
における冷媒の凝縮温度を検出する凝縮温度検出
手段Ｐ１とを備えるとともに、圧縮機１の容量毎
に、冷媒の蒸発温度および凝縮温度をパラメータ
として、容量で定まる冷媒循環量に適合するよう
設定された電動膨張弁８の適正開度計算式を記憶
する記憶手段５０と、上記蒸発温度検出手段TH
５および凝縮温度検出手段Ｐ１の信号を受け、こ
れらの信号と圧縮機１の運転容量とに基づいて上
記記憶手段５０の適正開度計算式により電動膨張
弁８の適正開度を演算する演算手段５１と、該演
算手段５１の信号を受け、電動膨張弁８の開度を
上記適正開度になるように制御する制御手段５２
とを備えたことを特徴とする冷凍装置。1. In a refrigeration system equipped with a refrigeration cycle in which a variable capacity compressor 1, a condenser 12, an electric expansion valve 8 for reducing the pressure of refrigerant, and an evaporator 6 are sequentially connected, the evaporation temperature of the refrigerant in the evaporator 6 is determined. evaporation temperature detection means TH5 to detect and the condenser 12
and a condensation temperature detection means P1 for detecting the condensation temperature of the refrigerant in the compressor 1, and the evaporation temperature and condensation temperature of the refrigerant are set as parameters for each capacity of the compressor 1 to match the refrigerant circulation amount determined by the capacity. a storage means 50 for storing an appropriate opening degree calculation formula for the electric expansion valve 8; and the evaporation temperature detection means TH.
5 and the condensing temperature detection means P1, and calculates the appropriate opening degree of the electric expansion valve 8 based on the appropriate opening degree calculation formula of the storage means 50 based on these signals and the operating capacity of the compressor 1. 51, and a control means 52 which receives the signal from the calculation means 51 and controls the opening degree of the electric expansion valve 8 to the above-mentioned appropriate opening degree.
A refrigeration device characterized by comprising: