JP4483141B2

JP4483141B2 - Air conditioner

Info

Publication number: JP4483141B2
Application number: JP2001217518A
Authority: JP
Inventors: 亮一高藤; 啓夫中村; 正之野中; 厚大塚
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 2001-07-18
Filing date: 2001-07-18
Publication date: 2010-06-16
Anticipated expiration: 2021-07-18
Also published as: JP2003028536A

Description

【０００１】
【発明の属する技術分野】
本発明は、冷凍サイクルの凝縮熱で室内空気を加熱する除湿運転が可能な空気調和機の制御に関する。
【０００２】
【従来の技術】
従来、サイクル再熱除湿可能な空気調和機が特開昭５４-４７３５３公報（文献１）に記載のものが知られている。この文献１には、室内熱交換器を冷却（除湿）部分と加熱部分とに分割し、室外熱交換器を凝縮器とした冷房サイクルによるいわゆる冷房サイクル除湿運転に加えて、室外熱交換器を蒸発器とした暖房サイクルによるいわゆる暖房サイクル除湿運転も行えるようにし吹き出し空気温度を十分高くできるようにすることが記載されている。
【０００３】
なお、この種の空気調和機として特開平１０-２６４３５公報（文献２）、及び特開平１１-３２５６３７公報（文献３）が知られている。
【０００４】
【発明が解決しようとする課題】
ところが、これら文献には、暖房サイクル除湿運転を具体的な制御手段が示されていない。
【０００５】
本発明の目的は、低外気温度においても吹き出し温度低下の少ない暖房サイクル除湿運転において、室内機の吹き出し空気温度と除湿量を制御する手段を提供することにある。
【０００６】
【課題を解決するための手段】
上記目的は、圧縮機、室外熱交換器、第１の絞り装置、除湿運転の時に動作する第２の絞り装置を介して分割された室内熱交換器を備えた空気調和機において、前記室外熱交換器が蒸発器となる暖房サイクル除湿運転時は、前記室外熱交換器のファンの風量を制御することで、前記室外熱交換器が凝縮器となる冷房サイクル除湿運転時は、前記圧縮機の能力を制御することで、前記分割された室内熱交換器のうち冷媒流れ方向後段の室内熱交換器の温度を調節することで達成される。
【０００７】
また上記目的は、圧縮機、室外熱交換器、第１の絞り装置、除湿運転の時に動作する第２の絞り装置を介して分割された室内熱交換器を備えた空気調和機において、前記室外熱交換器が蒸発器となる暖房サイクル除湿運転時は、前記室外熱交換器のファンの風量を制御することで、前記室外熱交換器が凝縮器となる冷房サイクル除湿運転時は、前記圧縮機の能力を制御することで、前記分割された室内熱交換器のうち冷媒流れ方向後段の室内熱交換器の温度を調節するようにし、前記室外熱交換器が蒸発器となる暖房サイクル除湿運転時は、前記圧縮機の回転数を制御することで、前記室外熱交換器が凝縮器となる冷房サイクル除湿運転時は、前記室外熱交換器のファンの風量を制御することで、前記分割された室内熱交換器のうち冷媒流れ方向前段の室内熱交換器の温度を調節することで達成される。
【０００８】
【発明の実施の形態】
以下、本発明の一実施例を図面に基づいて説明する。図１は本発明の一実施例に係る空気調和機の系統図である。
【０００９】
図１において、圧縮機１、冷房サイクルと暖房サイクルを切換える四方弁２、室外熱交換器３、冷房運転及び暖房運転の時に絞り作用を行う電動膨張弁等の第１の絞り装置４、除湿運転時に絞り作用を行う第２の絞り装置(除湿弁ともいう)７及び第２の絞り装置７を介して二分割された室内熱交換器５，６が冷媒配管によって接続されている。圧縮機１、四方弁２、室外熱交換器３、第１の絞り装置４、室内熱交換器６、第２の絞り装置７及び室内熱交換器５がこの順に接続されることで冷凍サイクルが形成される。
【００１０】
図示しない室外機には、圧縮機１、四方弁２、室外熱交換器３、第１の絞り弁４及び室外熱交換器３に通風する室外ファン８が備えられ、図示しない室内機には、室内熱交換器５、６、第２の絞り装置７及び室内熱交換器５、６に通風し空調対象空間(室内)に熱交換された空気を通風する貫流タイプの室内ファン９が備えられている。
【００１１】
室内温度検出手段１０は、室内熱交換器５、６の風上側に配置され室内の温度を検出する。室内湿度検出手段１１は、室内熱交換器５、６の風上側に配置され室内の湿度を検出する。室外温度検出手段１２は、室外機に取り付けられ室外の温度(外気温)を検出する。
【００１２】
圧縮機駆動回路１３は、密閉チャンバ内に設けられスクロールなどの圧縮要素を駆動する直流ブラシレス電動機や誘導電動機等を回転数可変に制御するインバータ及びインバータのスイッチング制御を行う制御回路等を備えている。室外ファン駆動回路１４は、室外ファン８のファンモータをインバータ等により回転数可変に駆動制御する。室内ファン駆動回路１５は、室内ファン９のファンモータをインバータ等により回転数可変に駆動制御する。室内制御装置１６は、室内温度検出手段(室内温度センサ)１０及び室内湿度検出手段(室内湿度センサ)１１からの検出データ、リモコン２０によって設定された設定温度及び設定湿度等の運転条件、室外制御装置１７から送出された各種データに基づいて各種制御指令を生成する。具体的には、室内ファン駆動回路１５、第２の絞り装置７等を制御する。室外制御装置１７は、室外温度検出手段(室外温度センサ)１２等からの信号を取り込み、圧縮機駆動回路１３、室外ファン駆動回路１４、第１の絞り装置４等の制御を行う。
【００１３】
室外制御装置１７と室内制御装置１６とは互いに通信を行う。そして各温度、湿度検出手段からの信号や各駆動回路への回転数等の指令は、必要ならば室外制御装置１７と室内制御装置１６の間で通信が行われる。
【００１４】
冷房運転時または冷房サイクル除湿運転においては、四方弁２を図１の実線のように切り替え、図１の実線矢印の方向に冷媒が流れることでサイクルを構成する。
【００１５】
以上のように構成された空気調和機の動作について説明する。
【００１６】
冷房運転時は、圧縮機１で圧縮された高温高圧のガス冷媒が室外熱交換器３で空気へ放熱することで凝縮して液冷媒となり、第１の絞り装置４によって膨張して室内熱交換器５、６で空気から吸熱することで蒸発して圧縮機１へ戻る。第２の絞り装置７は、絞り量が全開状態(流路抵抗が冷媒配管に近い状態)と絞った状態を選択可能なものであり、冷房運転時には全開にする。なお、この第２の絞り装置７は、２方弁とオリフィスの並列回路でもよく、この場合冷房運転時には、２方弁を全開にする。
【００１７】
暖房運転時は、四方弁２を図１の破線の方向に切り替え、破線の方向に冷媒を流す。このとき圧縮機１で圧縮されたガス冷媒は、室内熱交換器５、６で空気へ放熱することで凝縮し、第１の絞り装置４によって膨張して室外熱交換器３で空気から吸熱することで蒸発して圧縮機１へ戻る。暖房運転時でも第２の絞り装置７を全開にする。
【００１８】
冷房サイクル除湿運転時は、冷房運転時と冷媒の流れる方向は同じであるが、第１の絞り装置４を全開にし、第２の絞り装置７を絞った状態にする。室内熱交換器５によって冷媒は空気へ放熱することで凝縮するので、この室内熱交換器５は加熱器(凝縮器)として動作し、室内熱交換器６によって冷媒は、空気から吸熱することで蒸発するので、この室内熱交換器６は冷却器(蒸発器)として動作する。
【００１９】
このとき圧縮機１の回転数を変化させることにより、冷却器として働く室内熱交換器６における冷媒の蒸発温度を変化させて、潜熱能力(空気中の水分を液化させる能力)を変化させることができる。したがって室内の湿度は、主として圧縮機１の回転数を変化させる(冷媒循環量を変化させる)ことにより制御される。
【００２０】
一方、室外ファン８の回転数を変化させることにより、加熱器として働く室内熱交換器５における加熱能力を変化させることができる。したがって室内の温度は、主として室外ファン８の回転数を変化させる(室内熱交換器６に流入する冷媒の温度を変化させる)ことにより制御される。
【００２１】
このように、加熱と冷却の両方を室内熱交換器５、６で行うことにより、空気の温度を低下させずに空気中の水分のみを取り除く等温除湿運転、空気を加熱しながら水分を取り除く暖房気味除湿運転、空気を冷やしながら除湿を行う冷房気味除湿運転のいずれの運転も可能となる。
【００２２】
暖房サイクル除湿運転時は、暖房運転時と冷媒の流れる方向は同じであるが、第１の絞り装置４を全開にし、第２の絞り装置７を絞った状態にすることにより、室内熱交換器５によって冷媒は空気へ放熱することで凝縮するので、この室内熱交換器５は加熱器として動作する。また、第２の絞り装置７によって膨張した冷媒は室内熱交換器６に流入し、空気から吸熱することで蒸発するので、この室内熱交換器６は冷却器として動作する。
【００２３】
このとき室外ファン８の回転数を変化させることにより、冷却器として働く室内熱交換器６における冷媒の蒸発温度が変化して、潜熱能力を変化させることができる。この理由を説明する。暖房サイクル除湿運転において蒸発器となる熱交換器は室外熱交換器３及び室内熱交換器６である。室外ファン８の回転数の変化は室外熱交換器３の能力を変化させることを意味する。室外熱交換器３及び室内熱交換器６の蒸発器としての仕事量は他の条件が同一条件であれば一定である。ここで室外ファン８の回転数のみを増加させて室外熱交換器３の能力を増大させると、室外熱交換器３の仕事量が増加する。この増加分室内熱交換器６の仕事量が低下するため、潜熱能力(除湿能力)が低下する。したがって室内の湿度は、主として室外ファン８の回転数を変化させることにより制御することができる。
【００２４】
一方圧縮機１の回転数を変化させることにより、加熱器として働く室内熱交換器５における加熱能力を変化させることができる。この理由は、圧縮機の回転数を増加させることで冷媒循環量が増加し、室内熱交換器５に流入する高温高圧の冷媒量が増加するためである。したがって室内の温度は、主として圧縮機１の回転数を変化させることにより制御することができる。このように、加熱と冷却の両方を室内熱交換器５、６で行うことにより、暖房サイクル除湿運転において、空気の温度を低下させずに空気中の水分のみを取り除く等温除湿運転、空気を加熱しながら水分を取り除く暖房気味除湿運転が可能となる。特に暖房サイクル除湿運転では室外温度が低下しても、吹き出し温度を高く保つことが出来るため、低室外温度においても快適性を損なわない。
【００２５】
以上、冷房除湿運転及び暖房除湿運転における温度制御及び湿度制御の基本的な考え方を説明した。ところで、暖房除湿運転を行う際には種々の制約条件があり、この条件下で運転を行わないと各種問題が生じることが判明した。以下、この点について説明する。
【００２６】
図２（ａ）に暖房サイクル除湿運転における圧縮機回転数と吹き出し空気温度の関係を示す。暖房サイクル除湿運転において、圧縮機の回転数を増大させることで吹出し空気温度を上昇させることができることが理解される。図２において室内の温度、湿度は一定とする。図２（ａ）によれば、圧縮機回転数が低下すると冷媒循環量が低下するので、加熱能力だけでなく、潜熱能力も低下する。このため室内熱交換器５の温度が露点以下にならず除湿運転が設定されているにもかかわらず除湿しなくなってしまう。したがって、圧縮機回転数の下限を設定する必要がある。例えば室外ファン回転数３の下限(室外ファン３が停止した状態であり、この状態が最も室内熱交換器の仕事量が増加する)を、除湿量が０となる圧縮機回転数とする。その下限を白丸で示す。圧縮機回転数が高くなれば加熱能力が高くなるので空気吹出し温度は上昇する。しかし、圧縮機回転数が低下すると室内熱交換器５の冷却能力が低下するので圧縮機回転数の下限を設けている。しかも、この圧縮回転数の下限は外気温度によって変化させている。
【００２７】
図２（ｂ）は外気温度が変化した場合の圧縮機回転数の下限を結んだものである。外気温度が高くなるほど圧縮機回転数の下限が高くなるように設定している。これは、外気温が高いと室温も高くなり、室内熱交換器５の蒸発温度が高い低圧縮機回転数条件では、室内熱交換器５の温度が露点以下にならず除湿しないためである。なお、この外気温度に対応した圧縮機回転数の下限を、想定される外気温度範囲において、除湿可能な一定値としてもよい。
【００２８】
次に、圧縮機回転数の上限について説明する。図１において、熱交換器温度検出手段１８は、暖房サイクル除湿運転時に加熱器として機能する室内熱交換器６の温度を検出する。暖房サイクル除湿運転時における室温と加熱器である室内熱交換器６の温度の関係を図３（ａ）に示す。図３において外気温度を一定とする。圧縮機回転数を変化させない条件において室温が高いほど加熱器（室内熱交換器６）温度は高くなり、冷媒の凝縮量が減少するため凝縮圧力が高くなってしまう。暖房サイクル除湿運転において凝縮器として動作する熱交換器は加熱器として作用する室内熱交換器５のみであり、冷房サイクル除湿運転において凝縮器として動作する熱交換器は室外熱交換器及び加熱器として作用する室内熱交換器６である。これらの伝熱管容積を比較すると、明らかに暖房サイクル除湿運転時における凝縮器のほうが少ない。このため、暖房サイクル除湿運転の凝縮圧力が冷房サイクル除湿運転の凝縮圧力よりも上昇しやすい。この状態は圧縮機の信頼性の点で問題となる。そこで、加熱器温度に対する圧縮機回転数の上限を設ける必要がある。
【００２９】
詳細に説明する。加熱器として作用する室内熱交換器６の凝縮圧力が上昇する要因として２つの要因が挙げられる。第１は圧縮機回転数であり、第２は室温（外気温）である。圧縮機回転数が高いほど吹き出し空気温度は高くなるが、加熱器である室内熱交換器６の凝縮圧力も上昇するため、圧縮機の信頼性の点からあまり圧縮機回転数を高くすることができない。さらに、外気温が高いと、室外熱交換器３の蒸発圧力が増加し、圧縮機の吸込圧力が増大するので、加熱器である室内熱交換器５の凝縮圧力も上昇するため、外気温度が高いほど圧縮機回転数の上限は低下し、加熱能力だけでなく除湿量も低下してしまう。このため外気温度に対する圧縮機回転数の上限を設定する必要がある。
【００３０】
暖房サイクル除湿運転時に室温（外気温）が上昇し、加熱器である室内熱交換器６の温度も上昇した場合、熱交換器温度検出手段１２より検出された温度より図３（ｂ）に示す関係から圧縮機回転数が算出され、室外制御装置１７より圧縮機駆動回路１３へ出力される。この結果圧縮機回転数は低下し、室内熱交換器６の温度は一定の温度を保つことが出来る。このことで凝縮圧力の過上昇を防ぎ室内の温度が高くても信頼性の高い除湿運転が可能となる。
【００３１】
なお、後述するが、暖房サイクル除湿における圧縮機回転数の上限は必ずしも設ける必要はない。
【００３２】
暖房サイクル除湿運転における室外ファン回転数と除湿量の関係を図４（ａ）に示す。図４において室内の温度、湿度は一定とする。前述したように室外ファン回転数が高いほど除湿量は少なくなる。その上限(除湿量が０となる回転数)を白丸で示す。これは、前述したように、室外熱交換器３と共に蒸発器として作用する室内熱交換器６（冷却器）の能力が低下するためである。
【００３３】
また、外気温度が低下すると室外熱交換器の能力が低下するので、室外ファン８の回転数の上限は増加する。図４（ｂ）に外気温度が変化した場合の室外ファン回転数の上限を結んだグラフを示した。
【００３４】
次に、本実施の形態における暖房サイクル除湿運転制御のアルゴリズムを図５に基づいて説明する。
【００３５】
ステップ１０１においてリモコン２０により室温Ｔｓと湿度Ｈｓの目標値が設定されると、ステップ１０２において現在の室温Ｔｒ、湿度Ｈｒ、外気温度Ｔｏを読み込む。室温は、図１における室内温度検出手段１０、湿度は室内湿度検出手段１１、外気温度は室外温度検出手段１２により検出される。
【００３６】
ステップ１０３において現在の室外温度Ｔｏが暖房サイクル除湿運転が可能な室外温度の上限Ｔｏｓｅｔ以下であるかどうか判定し、現在の室外温度Ｔｏが室外温度上限Ｔｏｓｅｔ以上であれば、冷房サイクル除湿運転を行うモードに入る。
【００３７】
ステップ１０３において現在の室外温度Ｔｏが室外温度上限Ｔｏｓｅｔ以下であれば、ステップ１０５において現在の室温Ｔｒと設定室温Ｔｓの差ΔＴを算出し、ステップ１０６において除湿運転を行うか他の運転を行うか判定する。ここで、除湿運転を行うか否かの判定は、設定温度の上下一定範囲に入っているか否かで判定する。この範囲からはずれている場合は、除湿運転が設定されている場合であっても冷房運転や暖房運転を行う。このようにした理由は、設定温度から現在の室温から大きく外れている場合、まず室温を設定温度近傍にしてから除湿を行うと言う考え方に基づく。ΔＴが大きい場合、冷房が選択されると湿気もとれ、暖房が選択されると室内の相対湿度が減少するので、湿度も低下する。したがって、その後除湿運転に入ってもある程度湿度が低下しているので、使用者の要求に適合する。
【００３８】
ステップ１０７において除湿運転範囲よりも室温が高い場合は冷房運転を行い、除湿運転範囲よりも室温が低い場合は暖房運転を行う。
【００３９】
除湿運転の範囲は、暖房サイクル除湿運転では吹き出し空気温度を高くできるので、室温が低い場合については下限を大きくとることができる(例えば設定温度+２℃〜-５℃)。
【００４０】
ステップ１０６において除湿運転の範囲にΔＴが入っていると判断されたならば、ステップ１０８において、外気温度Ｔｏに対応した初期圧縮機回転数Ｎｃｍｉｎおよび初期室外ファン回転数Ｎｆｍｉｎを読み込む。ここでＮｃｍｉｎは図２（ｂ）に示した圧縮機回転数の下限で、外気温より図２（ｂ）に示した関係を用いて算出する。また、Ｎｆｍａｘは図４（ｂ）に示した室外ファン回転数の上限で、外気温より図４（ｂ）に示した関係を用いて算出する。
【００４１】
ステップ１０９においては、設定温度Ｔｓと室内温度Ｔｒとの差によって、初期圧縮機回転数Ｎｃｍｉｎを補正して圧縮機回転数Ｎｃを求める。室温上昇力の最も小さい圧縮機最小回転数に温度偏差に応じた値を加算して圧縮機１の回転数を決定するという考え方である。設定温度Ｔｓと室内温度Ｔｒとの差が負になった時は、この値を０として扱う。すなわち、圧縮機は最小回転数Ｎｃｍｉｎで運転されることとなる。
【００４２】
また、設定湿度Ｈｓと室内湿度Ｈｒとの差によって、初期室外ファン回転数Ｎｆｍａｘを補正して室外ファン回転数Ｎｆを求める。除湿能力が最も小さい最大室外ファン回転数から湿度偏差に応じた値を引いて室外ファン８の回転数を決定するという考え方である。
【００４３】
このように圧縮機回転数と室外ファン回転数を設定することにより、室内の温度と湿度を独立に制御することができる。
【００４４】
圧縮機回転数は除湿運転時における最高回転数Ｎｃmaxをあらかじめ定め、室外ファン回転数は最低回転数Ｎｆｍｉｎをあらかじめ定めておいて、ステップ１０９において計算されたＮｃまたはＮｆがそれらを越えるときには、ステップ１１０において最大値または最小値を超えないように設定する。
【００４５】
圧縮機回転数の上限は、前述したように外気温が高い時は小さく、外気温が低い時は高くなるように決めている。
【００４６】
ステップ１１１において圧縮機回転数Ｎｃと室外ファン回転数Ｎｆとをそれぞれの駆動回路に出力する。最後にステップ１１２のタイマで一定時間経過したならば、ステップ１０２の室温、湿度、外気温度の読み込みに戻って以下のステップを繰り返す。
【００４７】
なお、図３に示した室内熱交換器５の温度に応じて圧縮機回転数の上限を設定する制御を保護機能として組み込むことも可能であるが、暖房サイクル除湿運転は、室内熱交換器５の凝縮能力を十分に取ることができる温度帯（外気温が低い場合のみ）で行うことをステップ１０３において設定されるので、外気温に対する圧縮機回転数の最大値を設定（ステップ１１０）しておくことで十分である。すなわち、外気温が高い時は暖房サイクル除湿ではなく冷房サイクル除湿が設定されることで、上記保護機能を必ずしも組み込む必要はない。
【００４８】
また、本図では省略したが、ステップ１０４以降にもステップ１０５以降のステップと同様のステップが存在し、△Ｔが除湿運転可能な範囲かどうかを判定することによって、冷房または暖房運転が実行される。
【００４９】
本実施の形態の制御により、使用者の好みに応じて湿度と温度の設定ができ、快適性の面で優れている。
【００５０】
本発明の第２の実施の形態の空気調和機について説明する。本実施の形態における空気調和機の構成は、第１の実施の形態で示した図１において第２の絞り装置７を絞り量可変にしたもので、それ以外の構成は第１の実施の形態と同様である。
【００５１】
このような構成にすることにより暖房サイクル除湿運転時は、暖房運転時と冷媒の流れる方向は同じであるが、第１の絞り装置４を全開にし、第２の絞り装置７を絞った状態にすることにより、室内熱交換器５は冷媒が蒸発して空気から吸熱する冷却器となり、室内熱交換器６は冷媒が凝縮して空気へ放熱する加熱器となる。このとき第２の絞り装置７の絞り量を変化させることにより、冷却器として働く室内熱交換器６における冷媒の蒸発温度が変化して、潜熱能力を変化させることができる。したがって室内の湿度は、主として第２の絞り装置７の絞り量を変化させることにより制御される。一方圧縮機１の回転数を変化させることにより、加熱器として働く室内熱交換器５における加熱能力を変化させることができる。したがって室内の温度は、主として圧縮機１の回転数を変化させることにより制御される。
【００５２】
このように、加熱と冷却の両方を室内熱交換器５、６で行うことにより、暖房サイクル除湿運転において、空気の温度を低下させずに空気中の水分のみを取り除く等温除湿運転、空気を加熱しながら水分を取り除く暖房気味除湿運転が可能となる。特に暖房サイクル除湿運転では室外温度が低下しても、吹き出し温度を高く保つことが出来るため、低室外温度においても快適性を損なわない。
【００５３】
暖房サイクル除湿運転における第２の絞り装置７の絞り量と除湿量の関係を図６（ａ）に示す。図６において室内の温度、湿度は一定とする。第２の絞り装置７の絞り量が大きいほど除湿量は多くなることが理解される。しかし、第２の絞り装置７の絞り量を増加させる（絞る）と、吹き出し空気温度も高くなり加熱器である室内熱交換器６の凝縮圧力も上昇するため、圧縮機の信頼性の点からあまり絞り装置７の絞り量を大きくすることができない。したがってその上限を設ける必要がある。この上限を白丸で示す。図６（ｂ）は外気温度が変化した場合の絞り装置７の絞り量の上限を結んだものである。前述したように、外気温度が高くなると室内熱交換器５の凝縮圧力が上昇するので、外気温度が高いほど第２の絞り装置７の絞り量の上限が小さくなるように設定した。
【００５４】
本実施の形態による暖房サイクル除湿運転制御のアルゴリズムを図７に示す。図７においてステップ２０８、ステップ２０９、ステップ２１０以外の動作は、第１の実施の形態と同様である。ステップ２０８において外気温度Ｔｏに対応した初期圧縮機回転数Ｎｃｍｉｎおよび第２の絞り装置７の初期絞り量Ｎｅｍｉｎを読み込む。初期圧縮機回転数Ｎｃｍｉｎは第１の実施の形態と同様であり、初期絞り量Ｎｅｍｉｎは、絞り量を０とした値（全開）である。
【００５５】
ステップ２０９においては、設定湿度Ｈｒと室内湿度Ｈｓとの差に応じた値を補正値として、第２の絞り装置７の初期絞り量Ｎｅｍｉｎを補正して絞り量Ｎｅを求める。、圧縮機回転数Ｎｃは第１の実施の形態と同様に補正し求める。このように圧縮機回転数と第２の絞り装置７の絞り量を設定することにより、室内の温度と湿度を独立に制御することができる。
【００５６】
圧縮機回転数は除湿運転時における最高回転数Ｎｃmaxをあらかじめ定め、第２の絞り装置７の絞り量は、図６（ｂ）に示した絞り量の上限である最大絞り量Ｎｅｍａｘとし、ステップ２０９において計算されたＮｃまたはＮｅがそれらを越えるときには、ステップ２１０において最大値を超えないように設定する。ステップ２１１において圧縮機回転数Ｎｃと第２の絞り装置７の絞り量Ｎｅとをそれぞれの駆動回路に出力する。その後の動作は第１の実施の形態と同様である。
【００５７】
本実施の形態による制御により、使用者の好みに応じて湿度と温度の設定ができる。
【００５８】
さらに第３の実施の形態の空気調和機について説明する。
【００５９】
本実施の形態における空気調和機の構成を図８に示す。図８は、第１の実施の形態で示した図１において第２の絞り装置７を示すものである。図８の絞り部３１、３２は絞り量が全開と絞った状態を制御できるもので、冷房運転時と暖房運転時は全開の状態に制御される。また３３は逆止弁である。
【００６０】
暖房サイクル除湿運転において、冷媒が空気から吸熱する蒸発器は、室内熱交換器６および室外熱交換器であり、冷房サイクル除湿運転に比べ蒸発器が大きい。したがって、冷却器である室内熱交換器６の潜熱能力を確保するためには、第２の絞り装置７の絞り量を冷房サイクル除湿運転時よりも大きくする必要がある。
【００６１】
冷房サイクル除湿運転時は冷媒は図８の実線の方向に流れ、逆止弁３３の作用により絞り部３１のみを通る。また暖房サイクル除湿運転時は冷媒は破線の方向に流れ、逆止弁３３は作用しないので絞り部３１、３２を通る。
【００６２】
このような構成にすることにより、絞り部３１、３２の絞り量を適切に設定することで、暖房サイクル除湿運転時の第２の除湿弁７の絞り量を冷房サイクル除湿運転時よりも大きくすることが出来る。
【００６３】
以上より冷房サイクル除湿運転時と暖房サイクル除湿運転時で、第２の絞り装置７の絞り量を変えることで、室内、室外の広い温度範囲において除湿運転が可能となる。
【００６４】
以上実施の形態から明らかなように、暖房サイクル除湿運転において圧縮機回転数と室外ファン回転数を制御することにより、室内の温度と湿度を独立に制御でき使用者の好みに応じて湿度と温度の設定ができる。さらに、暖房サイクル除湿運転時に室温の上昇に応じて上昇する加熱器となる室内熱交換器の温度により圧縮機回転数を補正したり、冷房サイクル除湿時と暖房サイクル除湿時で第２の絞り装置の絞り量を変えることで、室内、室外の広い温度範囲において信頼性の高い除湿運転が可能となる。
【００６５】
【発明の効果】
以上本発明によれば、暖房サイクル除湿運転を具体的な制御手段を提供することができる。
【図面の簡単な説明】
【図１】本発明の実施の形態における空気調和機の系統図。
【図２】（ａ）、（ｂ）ともに本発明の吹き出し空気温度によって圧縮機回転数を決定する特性図。
【図３】（ａ）、（ｂ）ともに本発明の加熱器温度によって圧縮機回転数を決定する特性図。
【図４】（ａ）、（ｂ）ともに本発明の除湿量によって室外ファン回転数を決定する特性図。
【図５】本発明の第１の実施の形態における除湿運転の制御アルゴリズムを示すフローチャート。
【図６】（ａ）、（ｂ）ともに本発明の除湿量によって第２の絞り装置の絞り量を決定する特性図。
【図７】本発明の第２の実施の形態における除湿運転の制御アルゴリズムを示すフローチャート。
【図８】本発明の第３の実施の形態における第２の絞り装置の概略図。
【符号の説明】
１…圧縮機、２…四方弁、３…室外熱交換器、４…第１の絞り装置、５、６…室内熱交換器、７…第２の絞り装置、８…室外ファン、９…室内ファン、１０…室内温度検出手段、１１…室内湿度検出手段、１２…室外温度検出手段、１３…圧縮機駆動回路、１４…室外ファン駆動回路、１５…室内ファン駆動回路、１６…室内制御装置、１７…室外制御装置、１８…熱交換器温度検出手段、２０…リモコン、３１、３２…絞り部、３３…逆止弁。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to control of an air conditioner capable of dehumidifying operation in which indoor air is heated by condensation heat of a refrigeration cycle.
[0002]
[Prior art]
Conventionally, an air conditioner that can perform cycle reheat dehumidification is disclosed in JP-A-54-47353 (Reference 1). In this document 1, an indoor heat exchanger is divided into a cooling (dehumidification) portion and a heating portion, and in addition to a so-called cooling cycle dehumidification operation by a cooling cycle using an outdoor heat exchanger as a condenser, an outdoor heat exchanger is provided. It is described that a so-called heating cycle dehumidifying operation can be performed by a heating cycle as an evaporator so that the blown air temperature can be sufficiently increased.
[0003]
As this type of air conditioner, Japanese Patent Application Laid-Open No. 10-26435 (Reference 2) and Japanese Patent Application Laid-Open No. 11-325637 (Reference 3) are known.
[0004]
[Problems to be solved by the invention]
However, these documents do not show specific control means for the heating cycle dehumidifying operation.
[0005]
An object of the present invention is to provide means for controlling the blown air temperature and the amount of dehumidification of an indoor unit in a heating cycle dehumidification operation in which the blowout temperature decreases little even at low outside air temperatures.
[0006]
[Means for Solving the Problems]
The above object is achieved in an air conditioner having an indoor heat exchanger divided through a compressor, an outdoor heat exchanger, a first expansion device, and a second expansion device that operates during a dehumidifying operation. The exchanger becomes an evaporator Heating cycle During dehumidifying operation By controlling the air volume of the fan of the outdoor heat exchanger, and during the cooling cycle dehumidifying operation in which the outdoor heat exchanger becomes a condenser, by controlling the capacity of the compressor, This is achieved by adjusting the temperature of the indoor heat exchanger at the latter stage in the refrigerant flow direction among the divided indoor heat exchangers.
[0007]
The above object is also provided in an air conditioner having an indoor heat exchanger divided through a compressor, an outdoor heat exchanger, a first expansion device, and a second expansion device that operates during a dehumidifying operation. Heat exchanger becomes evaporator Heating cycle During dehumidifying operation In the cooling cycle dehumidifying operation in which the outdoor heat exchanger serves as a condenser by controlling the air volume of the fan of the outdoor heat exchanger, the capacity of the compressor is controlled by controlling the capacity of the compressor. In the heat exchanger, the temperature of the indoor heat exchanger downstream of the refrigerant flow direction is adjusted, and during the heating cycle dehumidifying operation in which the outdoor heat exchanger serves as an evaporator, the rotational speed of the compressor is controlled. In the cooling cycle dehumidifying operation in which the outdoor heat exchanger becomes a condenser, by controlling the air volume of the fan of the outdoor heat exchanger, This is achieved by adjusting the temperature of the indoor heat exchanger in the upstream of the refrigerant flow direction among the divided indoor heat exchangers.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a system diagram of an air conditioner according to an embodiment of the present invention.
[0009]
In FIG. 1, a compressor 1, a four-way valve 2 that switches between a cooling cycle and a heating cycle, an outdoor heat exchanger 3, a first expansion device 4 such as an electric expansion valve that performs a throttling operation during cooling and heating operations, and a dehumidifying operation A second throttle device (also referred to as a dehumidifying valve) 7 that sometimes performs a throttle action and the indoor heat exchangers 5 and 6 that are divided into two through the second throttle device 7 are connected by a refrigerant pipe. The compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the first expansion device 4, the indoor heat exchanger 6, the second expansion device 7, and the indoor heat exchanger 5 are connected in this order so that the refrigeration cycle is achieved. It is formed.
[0010]
The outdoor unit (not shown) includes the compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the first throttle valve 4, and the outdoor fan 8 that ventilates the outdoor heat exchanger 3, and the indoor unit (not shown) includes There is provided a once-through type indoor fan 9 that ventilates the indoor heat exchangers 5 and 6, the second expansion device 7, and the indoor heat exchangers 5 and 6 and ventilates the air that has been heat-exchanged into the air-conditioning target space (indoor). Yes.
[0011]
The indoor temperature detection means 10 is disposed on the windward side of the indoor heat exchangers 5 and 6 and detects the indoor temperature. The indoor humidity detecting means 11 is disposed on the windward side of the indoor heat exchangers 5 and 6 and detects the indoor humidity. The outdoor temperature detection means 12 is attached to the outdoor unit and detects an outdoor temperature (outside air temperature).
[0012]
The compressor drive circuit 13 includes a DC brushless motor that drives a compression element such as a scroll, an induction motor, and the like that are provided in a sealed chamber, and an inverter that controls the rotational speed of the compressor, a control circuit that performs inverter switching control, and the like. . The outdoor fan drive circuit 14 drives and controls the fan motor of the outdoor fan 8 with an inverter or the like so that the rotational speed can be varied. The indoor fan drive circuit 15 drives and controls the fan motor of the indoor fan 9 with an inverter or the like so that the rotational speed can be varied. The indoor control device 16 includes detection data from the indoor temperature detection means (indoor temperature sensor) 10 and the indoor humidity detection means (indoor humidity sensor) 11, operating conditions such as set temperature and set humidity set by the remote controller 20, outdoor control. Various control commands are generated based on various data sent from the device 17. Specifically, the indoor fan drive circuit 15, the second expansion device 7 and the like are controlled. The outdoor control device 17 takes in a signal from the outdoor temperature detecting means (outdoor temperature sensor) 12 and controls the compressor driving circuit 13, the outdoor fan driving circuit 14, the first throttling device 4, and the like.
[0013]
The outdoor control device 17 and the indoor control device 16 communicate with each other. And, if necessary, commands such as signals from each temperature and humidity detection means and the number of rotations to each drive circuit are communicated between the outdoor control device 17 and the indoor control device 16.
[0014]
In the cooling operation or in the cooling cycle dehumidifying operation, the four-way valve 2 is switched as shown by the solid line in FIG. 1, and the refrigerant flows in the direction of the solid line arrow in FIG.
[0015]
The operation of the air conditioner configured as described above will be described.
[0016]
During the cooling operation, the high-temperature and high-pressure gas refrigerant compressed by the compressor 1 is condensed to a liquid refrigerant by radiating heat to the air in the outdoor heat exchanger 3, and is expanded by the first expansion device 4 to exchange indoor heat. By absorbing heat from the air in the units 5 and 6, it evaporates and returns to the compressor 1. The second throttling device 7 can select a throttling amount in a fully open state (a state in which the flow path resistance is close to that of the refrigerant pipe) or a throttling state, and is fully open during the cooling operation. The second expansion device 7 may be a parallel circuit of a two-way valve and an orifice. In this case, the two-way valve is fully opened during the cooling operation.
[0017]
During the heating operation, the four-way valve 2 is switched in the direction of the broken line in FIG. 1 and the refrigerant flows in the direction of the broken line. At this time, the gas refrigerant compressed by the compressor 1 is condensed by radiating heat to the air in the indoor heat exchangers 5 and 6, expanded by the first expansion device 4, and absorbs heat from the air in the outdoor heat exchanger 3. Thus, it evaporates and returns to the compressor 1. Even during the heating operation, the second expansion device 7 is fully opened.
[0018]
During the cooling cycle dehumidifying operation, the direction of refrigerant flow is the same as that during the cooling operation, but the first throttle device 4 is fully opened and the second throttle device 7 is in the throttled state. Since the indoor heat exchanger 5 condenses the refrigerant by releasing heat to the air, the indoor heat exchanger 5 operates as a heater (condenser), and the indoor heat exchanger 6 absorbs heat from the air. Since it evaporates, this indoor heat exchanger 6 operates as a cooler (evaporator).
[0019]
At this time, by changing the rotation speed of the compressor 1, the evaporation temperature of the refrigerant in the indoor heat exchanger 6 serving as a cooler can be changed to change the latent heat capability (ability to liquefy moisture in the air). it can. Therefore, the indoor humidity is controlled mainly by changing the rotation speed of the compressor 1 (changing the refrigerant circulation amount).
[0020]
On the other hand, by changing the rotation speed of the outdoor fan 8, the heating capacity in the indoor heat exchanger 5 that functions as a heater can be changed. Therefore, the indoor temperature is controlled mainly by changing the rotational speed of the outdoor fan 8 (changing the temperature of the refrigerant flowing into the indoor heat exchanger 6).
[0021]
Thus, by performing both heating and cooling with the indoor heat exchangers 5 and 6, an isothermal dehumidifying operation that removes only moisture in the air without lowering the temperature of the air, heating that removes moisture while heating the air Both the dehumidifying operation and the air-cooling dehumidifying operation in which dehumidification is performed while cooling the air can be performed.
[0022]
During the heating cycle dehumidifying operation, the direction of refrigerant flow is the same as that during the heating operation, but by opening the first expansion device 4 and closing the second expansion device 7, the indoor heat exchanger Since the refrigerant is condensed by releasing heat to the air by 5, the indoor heat exchanger 5 operates as a heater. Further, the refrigerant expanded by the second expansion device 7 flows into the indoor heat exchanger 6 and evaporates by absorbing heat from the air, so that the indoor heat exchanger 6 operates as a cooler.
[0023]
At this time, by changing the rotation speed of the outdoor fan 8, the evaporating temperature of the refrigerant in the indoor heat exchanger 6 acting as a cooler changes, and the latent heat capacity can be changed. The reason for this will be explained. The heat exchangers that serve as evaporators in the heating cycle dehumidifying operation are the outdoor heat exchanger 3 and the indoor heat exchanger 6. The change in the rotational speed of the outdoor fan 8 means that the capacity of the outdoor heat exchanger 3 is changed. The work amount of the outdoor heat exchanger 3 and the indoor heat exchanger 6 as the evaporator is constant if other conditions are the same. Here, if only the rotational speed of the outdoor fan 8 is increased to increase the capacity of the outdoor heat exchanger 3, the work of the outdoor heat exchanger 3 increases. Since the work amount of the indoor heat exchanger 6 is reduced by this increase, the latent heat capability (dehumidification capability) is reduced. Therefore, the indoor humidity can be controlled mainly by changing the rotational speed of the outdoor fan 8.
[0024]
On the other hand, by changing the rotation speed of the compressor 1, the heating capacity in the indoor heat exchanger 5 that functions as a heater can be changed. This is because the amount of refrigerant circulation increases by increasing the rotation speed of the compressor, and the amount of high-temperature and high-pressure refrigerant flowing into the indoor heat exchanger 5 increases. Therefore, the indoor temperature can be controlled mainly by changing the rotational speed of the compressor 1. In this way, by performing both heating and cooling with the indoor heat exchangers 5 and 6, in the heating cycle dehumidifying operation, the isothermal dehumidifying operation for removing only moisture in the air without lowering the temperature of the air, heating the air In addition, a heating-like dehumidifying operation that removes moisture is possible. Especially in the heating cycle dehumidifying operation, even if the outdoor temperature is lowered, the blowing temperature can be kept high, so that comfort is not impaired even at a low outdoor temperature.
[0025]
The basic concept of temperature control and humidity control in the cooling and dehumidifying operation has been described above. By the way, when performing heating dehumidification operation, there exist various restrictions, and it became clear that various problems will arise if operation is not performed under these conditions. Hereinafter, this point will be described.
[0026]
FIG. 2A shows the relationship between the compressor speed and the blown air temperature in the heating cycle dehumidifying operation. In the heating cycle dehumidifying operation, it is understood that the blown air temperature can be increased by increasing the rotation speed of the compressor. In FIG. 2, the room temperature and humidity are constant. According to FIG. 2A, since the refrigerant circulation rate decreases as the compressor rotational speed decreases, not only the heating capacity but also the latent heat capacity decreases. For this reason, the temperature of the indoor heat exchanger 5 does not fall below the dew point and the dehumidification operation is set, but the dehumidification is not performed. Therefore, it is necessary to set the lower limit of the compressor speed. For example, the lower limit of the outdoor fan rotation speed 3 (the state in which the outdoor fan 3 is stopped and this state increases the work amount of the indoor heat exchanger most) is set as the compressor rotation speed at which the dehumidification amount becomes zero. The lower limit is indicated by a white circle. As the compressor speed increases, the heating capacity increases and the air blowing temperature rises. However, since the cooling capacity of the indoor heat exchanger 5 decreases when the compressor rotational speed decreases, a lower limit for the compressor rotational speed is provided. In addition, the lower limit of the compression speed is changed by the outside air temperature.
[0027]
FIG. 2B connects the lower limits of the compressor speed when the outside air temperature changes. The lower limit of the compressor speed is set higher as the outside air temperature becomes higher. This is because when the outside air temperature is high, the room temperature is also high, and the temperature of the indoor heat exchanger 5 does not fall below the dew point and does not dehumidify under the low compressor rotation speed condition where the evaporation temperature of the indoor heat exchanger 5 is high. In addition, it is good also considering the lower limit of the compressor rotation speed corresponding to this outside temperature as a fixed value which can dehumidify in the assumed outside temperature range.
[0028]
Next, the upper limit of the compressor rotation speed will be described. In FIG. 1, the heat exchanger temperature detection means 18 detects the temperature of the indoor heat exchanger 6 that functions as a heater during the heating cycle dehumidifying operation. FIG. 3A shows the relationship between the room temperature and the temperature of the indoor heat exchanger 6 that is a heater during the heating cycle dehumidifying operation. In FIG. 3, the outside air temperature is constant. The higher the room temperature is, the higher the room temperature is, the higher the temperature of the heater (indoor heat exchanger 6) is, and the more the refrigerant is condensed, the higher the condensing pressure. The heat exchanger that operates as a condenser in the heating cycle dehumidifying operation is only the indoor heat exchanger 5 that acts as a heater, and the heat exchanger that operates as a condenser in the cooling cycle dehumidifying operation is an outdoor heat exchanger and a heater. It is the indoor heat exchanger 6 which acts. Comparing these heat transfer tube volumes, obviously there are fewer condensers during the heating cycle dehumidification operation. For this reason, the condensation pressure in the heating cycle dehumidification operation is likely to rise higher than the condensation pressure in the cooling cycle dehumidification operation. This state becomes a problem in terms of the reliability of the compressor. Therefore, it is necessary to provide an upper limit of the compressor speed with respect to the heater temperature.
[0029]
This will be described in detail. There are two factors that increase the condensation pressure of the indoor heat exchanger 6 acting as a heater. The first is the compressor rotation speed, and the second is the room temperature (outside temperature). The higher the compressor speed, the higher the temperature of the blown air, but the condensing pressure of the indoor heat exchanger 6 that is a heater also increases, so the compressor speed may be increased too much from the viewpoint of the reliability of the compressor. Can not. Furthermore, when the outside air temperature is high, the evaporation pressure of the outdoor heat exchanger 3 increases, and the suction pressure of the compressor increases. Therefore, the condensation pressure of the indoor heat exchanger 5 that is a heater also increases, so the outside air temperature is increased. As the value increases, the upper limit of the compressor rotation speed decreases, and not only the heating capacity but also the dehumidification amount decreases. For this reason, it is necessary to set the upper limit of the compressor speed with respect to the outside air temperature.
[0030]
When the room temperature (outside air temperature) rises during the heating cycle dehumidifying operation and the temperature of the indoor heat exchanger 6 as a heater also rises, the temperature detected by the heat exchanger temperature detecting means 12 is shown in FIG. The compressor rotation speed is calculated from the relationship, and is output from the outdoor control device 17 to the compressor drive circuit 13. As a result, the rotational speed of the compressor decreases, and the temperature of the indoor heat exchanger 6 can be kept constant. This prevents an excessive increase in the condensation pressure and enables a highly reliable dehumidifying operation even if the room temperature is high.
[0031]
In addition, although mentioned later, the upper limit of the compressor rotation speed in heating cycle dehumidification does not necessarily need to be provided.
[0032]
FIG. 4A shows the relationship between the outdoor fan rotation speed and the dehumidifying amount in the heating cycle dehumidifying operation. In FIG. 4, the room temperature and humidity are constant. As described above, the higher the outdoor fan rotation speed, the smaller the dehumidification amount. The upper limit (the number of rotations at which the dehumidification amount becomes 0) is indicated by white circles. As described above, this is because the capacity of the indoor heat exchanger 6 (cooler) acting as an evaporator together with the outdoor heat exchanger 3 is reduced.
[0033]
Moreover, since the capability of an outdoor heat exchanger will fall if external temperature falls, the upper limit of the rotation speed of the outdoor fan 8 increases. FIG. 4B shows a graph connecting the upper limits of the outdoor fan rotation speed when the outside air temperature changes.
[0034]
Next, the algorithm of the heating cycle dehumidifying operation control in the present embodiment will be described based on FIG.
[0035]
When the target values of the room temperature Ts and the humidity Hs are set by the remote controller 20 in step 101, the current room temperature Tr, humidity Hr, and outside air temperature To are read in step 102. The room temperature is detected by the indoor temperature detecting means 10 in FIG. 1, the humidity is detected by the indoor humidity detecting means 11, and the outdoor temperature is detected by the outdoor temperature detecting means 12.
[0036]
In step 103, it is determined whether or not the current outdoor temperature To is equal to or lower than the upper limit Toset of the outdoor temperature at which the heating cycle dehumidifying operation is possible. If the current outdoor temperature To is equal to or higher than the outdoor temperature upper limit Toset, the cooling cycle dehumidifying operation is performed. Enter the mode.
[0037]
If the current outdoor temperature To is equal to or lower than the outdoor temperature upper limit Toset in step 103, the difference ΔT between the current room temperature Tr and the set room temperature Ts is calculated in step 105, and whether the dehumidifying operation or other operation is performed in step 106. judge. Here, whether or not to perform the dehumidifying operation is determined by whether or not the dehumidifying operation is within a certain range of the set temperature. When deviating from this range, the cooling operation or the heating operation is performed even when the dehumidifying operation is set. The reason for this is based on the idea that if the set temperature deviates significantly from the current room temperature, the room temperature is first brought close to the set temperature and then dehumidification is performed. When ΔT is large, humidity is reduced when cooling is selected, and the relative humidity inside the room decreases when heating is selected, so the humidity also decreases. Therefore, since the humidity is lowered to some extent even after the dehumidifying operation is started, the user's request is met.
[0038]
If the room temperature is higher than the dehumidifying operation range in step 107, the cooling operation is performed, and if the room temperature is lower than the dehumidifying operation range, the heating operation is performed.
[0039]
As for the range of the dehumidifying operation, since the blown air temperature can be increased in the heating cycle dehumidifying operation, the lower limit can be increased when the room temperature is low (for example, the set temperature + 2 ° C to -5 ° C).
[0040]
If it is determined in step 106 that ΔT is in the range of the dehumidifying operation, in step 108, the initial compressor rotational speed Ncmin and the initial outdoor fan rotational speed Nfmin corresponding to the outside air temperature To are read. Here, Ncmin is the lower limit of the compressor rotational speed shown in FIG. 2B, and is calculated from the outside air temperature using the relationship shown in FIG. 2B. Nfmax is the upper limit of the outdoor fan rotation speed shown in FIG. 4B, and is calculated from the outside air temperature using the relationship shown in FIG. 4B.
[0041]
In step 109, the compressor speed Nc is determined by correcting the initial compressor speed Ncmin based on the difference between the set temperature Ts and the room temperature Tr. The idea is to determine the number of revolutions of the compressor 1 by adding a value corresponding to the temperature deviation to the minimum number of revolutions of the compressor having the smallest room temperature increasing force. When the difference between the set temperature Ts and the room temperature Tr becomes negative, this value is treated as zero. That is, the compressor is operated at the minimum rotational speed Ncmin.
[0042]
Further, the outdoor fan rotational speed Nf is determined by correcting the initial outdoor fan rotational speed Nfmax based on the difference between the set humidity Hs and the indoor humidity Hr. The idea is to determine the rotational speed of the outdoor fan 8 by subtracting a value corresponding to the humidity deviation from the maximum outdoor fan rotational speed with the smallest dehumidifying capacity.
[0043]
By setting the compressor speed and the outdoor fan speed in this way, the indoor temperature and humidity can be controlled independently.
[0044]
The compressor rotational speed is determined in advance as the maximum rotational speed Ncmax during the dehumidifying operation, and the outdoor fan rotational speed is determined in advance as the minimum rotational speed Nfmin. If Nc or Nf calculated in step 109 exceeds these values, step 110 is performed. Set so that the maximum or minimum value is not exceeded.
[0045]
As described above, the upper limit of the rotational speed of the compressor is determined to be small when the outside air temperature is high and high when the outside air temperature is low.
[0046]
In step 111, the compressor rotation speed Nc and the outdoor fan rotation speed Nf are output to the respective drive circuits. Finally, when a predetermined time has elapsed in the timer of step 112, the process returns to reading of the room temperature, humidity, and outside air temperature in step 102, and the following steps are repeated.
[0047]
In addition, although it is also possible to incorporate the control which sets the upper limit of a compressor rotation speed according to the temperature of the indoor heat exchanger 5 shown in FIG. 3 as a protection function, heating cycle dehumidification operation is the indoor heat exchanger 5 Since it is set in step 103 that it is performed in a temperature range (only when the outside air temperature is low) in which sufficient condensation capacity can be obtained, the maximum value of the compressor speed with respect to the outside air temperature is set (step 110). It is enough to leave. That is, when the outside air temperature is high, not the heating cycle dehumidification but the cooling cycle dehumidification is set, so that the protection function does not necessarily need to be incorporated.
[0048]
Although omitted in this figure, steps similar to the steps after step 105 exist after step 104, and cooling or heating operation is executed by determining whether or not ΔT is within a dehumidifying range. The
[0049]
The control according to the present embodiment allows the humidity and temperature to be set according to the user's preference, which is excellent in terms of comfort.
[0050]
An air conditioner according to a second embodiment of the present invention will be described. The configuration of the air conditioner in the present embodiment is obtained by making the second diaphragm device 7 variable in FIG. 1 shown in the first embodiment, and the other configurations are the first embodiment. It is the same.
[0051]
With this configuration, during the heating cycle dehumidifying operation, the direction of refrigerant flow is the same as that during the heating operation, but the first expansion device 4 is fully opened and the second expansion device 7 is in the closed state. Thus, the indoor heat exchanger 5 becomes a cooler that evaporates the refrigerant and absorbs heat from the air, and the indoor heat exchanger 6 becomes a heater that condenses the refrigerant and radiates heat to the air. At this time, by changing the throttle amount of the second throttle device 7, the evaporation temperature of the refrigerant in the indoor heat exchanger 6 that functions as a cooler changes, and the latent heat capability can be changed. Therefore, the humidity in the room is controlled mainly by changing the amount of diaphragm of the second diaphragm device 7. On the other hand, by changing the rotation speed of the compressor 1, the heating capacity in the indoor heat exchanger 5 that functions as a heater can be changed. Therefore, the indoor temperature is controlled mainly by changing the rotational speed of the compressor 1.
[0052]
In this way, by performing both heating and cooling with the indoor heat exchangers 5 and 6, in the heating cycle dehumidifying operation, the isothermal dehumidifying operation for removing only moisture in the air without lowering the temperature of the air, heating the air In addition, a heating-like dehumidifying operation that removes moisture is possible. Especially in the heating cycle dehumidifying operation, even if the outdoor temperature is lowered, the blowing temperature can be kept high, so that comfort is not impaired even at a low outdoor temperature.
[0053]
FIG. 6A shows the relationship between the throttle amount of the second throttle device 7 and the dehumidifying amount in the heating cycle dehumidifying operation. In FIG. 6, the room temperature and humidity are constant. It is understood that the amount of dehumidification increases as the amount of expansion of the second expansion device 7 increases. However, if the throttle amount of the second throttle device 7 is increased (squeezed), the temperature of the blown air increases and the condensing pressure of the indoor heat exchanger 6 that is a heater also rises. Therefore, from the point of reliability of the compressor The diaphragm amount of the diaphragm device 7 cannot be increased too much. Therefore, it is necessary to set the upper limit. This upper limit is indicated by a white circle. FIG. 6B connects the upper limit of the throttle amount of the throttle device 7 when the outside air temperature changes. As described above, since the condensation pressure of the indoor heat exchanger 5 increases as the outside air temperature increases, the upper limit of the amount of restriction of the second expansion device 7 is set to be smaller as the outside air temperature is higher.
[0054]
FIG. 7 shows an algorithm for heating cycle dehumidifying operation control according to this embodiment. In FIG. 7, operations other than step 208, step 209, and step 210 are the same as those in the first embodiment. In step 208, the initial compressor rotational speed Ncmin corresponding to the outside air temperature To and the initial throttle amount Nemin of the second throttle device 7 are read. The initial compressor rotational speed Ncmin is the same as in the first embodiment, and the initial throttle amount Nemin is a value (full open) where the throttle amount is zero.
[0055]
In step 209, the aperture value Ne is obtained by correcting the initial aperture amount Nemin of the second aperture device 7 using a value corresponding to the difference between the set humidity Hr and the room humidity Hs as a correction value. The compressor rotation speed Nc is corrected and obtained in the same manner as in the first embodiment. Thus, by setting the compressor rotation speed and the throttle amount of the second throttle device 7, the indoor temperature and humidity can be controlled independently.
[0056]
The compressor rotational speed is determined in advance as the maximum rotational speed Ncmax during the dehumidifying operation, and the throttle amount of the second throttle device 7 is set to the maximum throttle amount Nemax which is the upper limit of the throttle amount shown in FIG. When Nc or Ne calculated in (1) exceeds them, step 210 is set so as not to exceed the maximum value. In step 211, the compressor rotational speed Nc and the throttle amount Ne of the second throttle device 7 are output to the respective drive circuits. The subsequent operation is the same as that of the first embodiment.
[0057]
By the control according to the present embodiment, the humidity and temperature can be set according to the user's preference.
[0058]
Furthermore, the air conditioner of 3rd Embodiment is demonstrated.
[0059]
The structure of the air conditioner in this Embodiment is shown in FIG. FIG. 8 shows the second diaphragm device 7 in FIG. 1 shown in the first embodiment. The throttle portions 31 and 32 in FIG. 8 can control a state where the throttle amount is fully opened, and are controlled to be fully open during the cooling operation and the heating operation. Reference numeral 33 denotes a check valve.
[0060]
In the heating cycle dehumidifying operation, the evaporator in which the refrigerant absorbs heat from the air is the indoor heat exchanger 6 and the outdoor heat exchanger, and the evaporator is larger than that in the cooling cycle dehumidifying operation. Therefore, in order to ensure the latent heat capability of the indoor heat exchanger 6 that is a cooler, it is necessary to make the amount of expansion of the second expansion device 7 larger than that in the cooling cycle dehumidifying operation.
[0061]
During the cooling cycle dehumidifying operation, the refrigerant flows in the direction of the solid line in FIG. 8 and passes only through the throttle portion 31 by the action of the check valve 33. Further, during the heating cycle dehumidifying operation, the refrigerant flows in the direction of the broken line and the check valve 33 does not act, so it passes through the throttle portions 31 and 32.
[0062]
With such a configuration, by appropriately setting the throttle amounts of the throttle units 31 and 32, the throttle amount of the second dehumidifying valve 7 during the heating cycle dehumidifying operation is made larger than that during the cooling cycle dehumidifying operation. I can do it.
[0063]
As described above, the dehumidifying operation can be performed in a wide temperature range indoors and outdoors by changing the throttle amount of the second expansion device 7 during the cooling cycle dehumidifying operation and the heating cycle dehumidifying operation.
[0064]
As is apparent from the above embodiments, the indoor temperature and humidity can be controlled independently by controlling the compressor speed and the outdoor fan speed in the heating cycle dehumidifying operation, so that the humidity and temperature can be controlled according to the user's preference. Can be set. Further, the compressor rotation speed is corrected by the temperature of the indoor heat exchanger that becomes a heater that rises as the room temperature rises during the heating cycle dehumidifying operation, and the second throttle device is used at the time of cooling cycle dehumidification and heating cycle dehumidification. By changing the amount of squeezing, it is possible to perform a highly reliable dehumidifying operation in a wide temperature range indoors and outdoors.
[0065]
【The invention's effect】
As described above, according to the present invention, specific control means can be provided for the heating cycle dehumidifying operation.
[Brief description of the drawings]
FIG. 1 is a system diagram of an air conditioner according to an embodiment of the present invention.
FIGS. 2A and 2B are characteristic diagrams for determining the compressor rotational speed based on the blown air temperature of the present invention.
FIGS. 3A and 3B are characteristic diagrams for determining the compressor rotation speed according to the heater temperature of the present invention.
FIGS. 4A and 4B are characteristic diagrams for determining the outdoor fan rotation speed according to the dehumidification amount of the present invention.
FIG. 5 is a flowchart showing a control algorithm of the dehumidifying operation in the first embodiment of the present invention.
FIGS. 6A and 6B are characteristic diagrams for determining the aperture amount of the second aperture device according to the dehumidification amount of the present invention.
FIG. 7 is a flowchart showing a control algorithm of a dehumidifying operation in the second embodiment of the present invention.
FIG. 8 is a schematic view of a second diaphragm device according to the third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Four-way valve, 3 ... Outdoor heat exchanger, 4 ... 1st expansion device, 5, 6 ... Indoor heat exchanger, 7 ... 2nd expansion device, 8 ... Outdoor fan, 9 ... Indoor Fan 10, indoor temperature detection means 11, indoor humidity detection means 12, outdoor temperature detection means 13, compressor drive circuit 14, outdoor fan drive circuit 15, indoor fan drive circuit 16, indoor control device DESCRIPTION OF SYMBOLS 17 ... Outdoor control apparatus, 18 ... Heat exchanger temperature detection means, 20 ... Remote control, 31, 32 ... Throttle part, 33 ... Check valve.

Claims

In an air conditioner including an indoor heat exchanger divided through a compressor, an outdoor heat exchanger, a first expansion device, and a second expansion device that operates during a dehumidifying operation, the outdoor heat exchanger is evaporated During the heating cycle dehumidifying operation as a cooler, the air volume of the fan of the outdoor heat exchanger is controlled, and during the cooling cycle dehumidifying operation as the condenser as a condenser, the capacity of the compressor is controlled. it is, air conditioner so as to adjust the temperature of the refrigerant flow direction downstream of the indoor heat exchanger of the divided interior heat exchanger.

2. The air conditioner according to claim 1, wherein, during the heating cycle dehumidifying operation in which the outdoor heat exchanger serves as an evaporator, the upper limit of the rotational speed of the fan of the outdoor heat exchanger is increased as the outside air temperature is lower.

In an air conditioner including an indoor heat exchanger divided through a compressor, an outdoor heat exchanger, a first expansion device, and a second expansion device that operates during a dehumidifying operation, the outdoor heat exchanger is evaporated During the heating cycle dehumidifying operation as a cooler, the air volume of the fan of the outdoor heat exchanger is controlled, and during the cooling cycle dehumidifying operation as the condenser as a condenser, the capacity of the compressor is controlled. By adjusting the temperature of the indoor heat exchanger in the downstream of the refrigerant flow direction among the divided indoor heat exchangers, and during the heating cycle dehumidifying operation in which the outdoor heat exchanger serves as an evaporator, the compressor In the cooling cycle dehumidifying operation in which the outdoor heat exchanger serves as a condenser, the air volume of the fan of the outdoor heat exchanger is controlled to control the number of rotations of the indoor heat exchanger. Of which, room heat in front of refrigerant flow direction Air conditioner so as to adjust the temperature of the exchanger.

4. In the heating cycle dehumidifying operation in which the outdoor heat exchanger is an evaporator according to claim 3, the lower the outside air temperature, the higher the upper limit of the rotational speed of the fan of the outdoor heat exchanger, The air conditioner which made the minimum of the rotation speed of the said compressor low, so that it is low.

5. The throttle amount of the second expansion device according to claim 1 , wherein the amount of expansion of the second expansion device is determined in a dehumidifying operation in which the outdoor heat exchanger is a condenser and in a dehumidifying operation in which the outdoor heat exchanger is an evaporator. An air conditioner designed to be different.