JP4265868B2

JP4265868B2 - Air conditioner

Info

Publication number: JP4265868B2
Application number: JP2000376518A
Authority: JP
Inventors: 円小田島
Original assignee: Toshiba Carrier Corp
Current assignee: Toshiba Carrier Corp
Priority date: 2000-12-11
Filing date: 2000-12-11
Publication date: 2009-05-20
Anticipated expiration: 2020-12-11
Also published as: JP2002181408A

Description

【０００１】
【発明の属する技術分野】
本発明は、冷，暖房および除湿運転可能のヒートポンプ式空気調和機に係り、特に高外気温（室外温度）と低室温（室内温度）との温度差が所定値以上である場合に、除湿運転時に閉弁される除湿絞り装置の弁体を断続的に開弁させることにより、圧縮機の潤滑特性の低下の防止ないし抑制を図った空気調和機に関する。
【０００２】
【従来の技術】
従来、この種の除湿運転可能のヒートポンプ式空気調和機の一例としては、等温ドライサイクル等の除湿制御運転サイクルを実現するために、除湿運転時、凝縮器と蒸発器としてそれぞれ作用する隣り合う２つの室内熱交換器同士の間の冷媒通路に、冷媒を絞る除湿絞り弁として絞り機能を備えたプリートポート二方弁等の除湿絞り装置を介装したものがある。この除湿絞り装置は、上記凝縮器と蒸発器とを、冷媒流に対して低損失で連結する低損失冷媒連通路を開閉する弁体と、弁座の接合面等に形成されたＶ溝等の冷媒絞り通路とを有し、除湿運転時には弁体を閉じて低損失冷媒通路を閉鎖し、冷媒絞り通路に冷媒を通して絞るようになっている。
【０００３】
【発明が解決しようとする課題】
しかしながら、このような従来の除湿絞り装置では、例えば外気温（室外温度）が室温（室内温度）よりも高く、その温度差が大きいために圧縮機の液戻りが増大し易い場合においても、除湿運転時には、除湿絞り装置の弁体により低圧力損失冷媒通路を常時閉弁して冷媒流量を冷媒絞り通路により常時絞っているために圧縮機の潤滑特性が悪化するという課題がある。
【０００４】
すなわち、一般に外気温が高い場合には、冷凍サイクルの高圧側圧力が高くなるので、室外設置の室外機内の圧縮機における吐出冷媒流量が減少し、冷凍サイクルを循環する冷媒流量は減少する。一方、室温が低い場合には、室内設置の室内機内の蒸発器における冷媒の蒸発量が減少して冷媒が液状態で圧縮機に戻る液戻り（液バック）量が増大する。しかも、液冷媒はガス状冷媒に比して潤滑油の含有量（希釈度）が少ないので、液バック量が多い場合には、冷媒と共に圧縮機内に戻る潤滑油量が不足して潤滑特性が悪化するという不具合が発生する。
【０００５】
図７はこのような外気温（室外温度）と室温（室内温度）との温度差と、圧縮機内の摺動部等所要の測定箇所の油膜の厚さとの相対関係を示している。この図７に示すように、高外気温と低室温との温度差が例えば１０℃以上の場合には被測定部の油膜の厚さが薄くなり、例えば図７中三角形で示される領域では圧縮機の潤滑特性が悪化する領域を示している。
【０００６】
そして、このように圧縮機の潤滑特性が悪化する場合には、冷凍サイクルを循環する冷媒流量を減少させることにより液戻りを減少させて圧縮機の潤滑性能を改善させることは可能であるが、この方法では同時に冷媒流量の減少による空調能力の低下等の新たな不具合が発生するという課題がある。
【０００７】
本発明はこのような事情を考慮されてなされたものであり、その目的は、除湿運転時において高外気温と低室温との温度差が所定値よりも大きいときに圧縮機の潤滑特性が悪化するのを防止ないし抑制して信頼性を向上させることができる空気調和機を提供することにある。
【０００８】
【課題を解決するための手段】
本願請求項１に係る発明は、冷凍サイクルを構成する利用側熱交換器を熱的に２分割してなり、除湿運転時には凝縮器と蒸発器としてそれぞれ運転される第１の利用側熱交換器および第２の利用側熱交換器と、これら第１，第２の利用側熱交換器同士を冷媒流に対して低圧力損失で連結する低圧力損失冷媒通路およびこの低圧力損失冷媒通路を除湿運転時に閉鎖する弁体およびこの弁体による低圧力損失冷媒通路の閉鎖時に上記第１，第２の利用側熱交換器同士を連通させるように形成されて冷媒流を絞る冷媒絞り通路を備えた除湿絞り装置と、室外温度を検出する室外温度センサと、室内温度を検出する室内温度センサと、を具備している空気調和機において、除湿運転時に上記室内温度センサにより検出された室内温度よりも上記室外温度センサにより検出された室外温度の方が高く、かつこれらの温度差が所定値以上のときに、上記除湿絞り装置の弁体の閉弁を断続的に開弁させる制御装置を設けたことを特徴とする空気調和機である。
【０００９】
この発明によれば、除湿運転時、室外温度（外気温）と室内温度（室温）との温度差が所定値（例えば１１℃）以上であると、制御装置により検出されると、除湿絞り装置の弁体の閉鎖（閉弁）が制御装置により断続的に開放（開弁）される。
【００１０】
このために、第１の利用側熱交換器から除湿絞り装置に流入した液冷媒は、その弁体の閉弁時に、冷媒絞り通路のみを通って流量と圧力が共に絞られてから第２の利用側熱交換器内へ流入し、ここで蒸発してから再び圧縮機内へ戻される。この圧縮機内へ戻される冷媒流量は除湿絞り弁により絞られているので、減少するうえに、その冷媒中には潤滑油の含有量が少ない液冷媒が含まれているので、その分、潤滑油の圧縮機内への戻し量が減少する。
【００１１】
しかし、除湿絞り装置の弁体は所定時間閉弁後、所定時間開弁されて低圧力損失冷媒通路が開通されるので、その開弁時、第１，第２の利用側熱交換器同士がこの低圧力損失冷媒通路を介して連結される。このために、第１の利用側熱交換器から除湿絞り弁に流入した冷媒流は、低圧力損失冷媒通路を通って流量と圧力が殆ど絞られずに第２の利用側熱交換器内へ流入し、ここで蒸発してから再び圧縮機内へ戻される。この圧縮機内へ戻される冷媒流量は除湿絞り装置により殆ど絞られないので、その冷媒戻し量が増加する。このために、冷媒中に含まれている潤滑油の圧縮機内への戻し量も増大する。したがって、この後の除湿絞り弁の弁体の開閉の繰返しにより圧縮機内へ戻される潤滑油量の不足を防止できるので、圧縮機の潤滑特性の悪化を防止ないし低減できる。
【００１２】
請求項２に係る発明は、上記制御装置は、上記室外温度と上記室内温度との差に応じて上記除湿絞り装置の弁体の閉時間と開時間とをそれぞれ制御する開閉時間制御手段を具備していることを特徴とする請求項１記載の空気調和機である。
【００１３】
この発明によれば、除湿運転時に閉弁される除湿絞り装置の弁体の閉弁時間と、断続的に開弁される開弁時間とを、室外温度と室内温度との温度差に応じて制御装置により制御するので、室外温度と室内温度との温度差に応じた適切な量の潤滑油を冷媒を介して圧縮機内に戻すことができる。このために、圧縮機の潤滑特性の向上を図ることができる。
【００１４】
請求項３に係る発明は、上記制御装置は、上記室外温度と上記室内温度との温度差が所定値以下のときに上記圧縮機の運転周波数を所定値高くする圧縮機制御手段を具備していることを特徴とする請求項１または２記載の空気調和機である。
【００１５】
この発明によれば、上記請求項１に係る発明のように除湿運転時に閉弁される除湿絞り弁の弁体を断続的に開弁し、または請求項２に係る発明のように除湿絞り装置の開弁時間または閉弁時間を制御する一方、室外温度と室内温度との差が所定値以下のときには、圧縮機の運転周波数を所定値高くして回転数を増加させるので、高外気温時でも圧縮機から吐出される冷媒流量を増加させることができる。これにより、圧縮機内へ戻る冷媒流量が増加するので、この冷媒流量に含まれている潤滑油量も増加させることができ、圧縮機の潤滑特性の最適化を図ることができる。
【００１６】
【発明の実施の形態】
以下、本発明の実施形態を図１〜図７に基づいて説明する。なお、これらの図中、同一または相当部分には同一符号を付している。
【００１７】
図３は本発明の一実施形態である空気調和機１の冷凍サイクル図である。
【００１８】
この図３に示すようにこの空気調和機１は、図示しないインバータにより運転周波数が制御されて回転数が制御される圧縮機２、流路切換用の四方弁３、室外熱交換器４、減圧装置の一例である膨張弁５、第１の利用側となす第１の室内熱交換器６、開閉弁と絞り機能を備えた電磁弁等の除湿絞り装置７、第２の利用側となる第２の室内熱交換器８をこの順に順次冷媒配管９により接続して冷媒を循環させる閉じた冷凍サイクルを構成している。
【００１９】
また、室外熱交換器４には、これに外気を送風して熱交換を促進させるプロペラファン等の室外ファン１０を設け、これら室外ファン１０と室外熱交換器４等を収容する図示しない室外機ケース内には外気温（室外温度）を検出する外気温センサ１１とを設けている。一方、室内設置の図示しない室内機ケースには、第１，第２の室内熱交換器６，８等と、これら第１，第２の室内熱交換器６，８に室内空気を送風して熱交換を促進させると共に、熱交換された空調空気を室内へ送風する横流ファン等の共通の室内ファン１２と、室温（室内温度）を検出する室温センサ１３とを設けている。
【００２０】
さらに、この冷凍サイクルは、四方弁３の切換操作により冷媒を、図中実線矢印方向に循環させることにより冷房または除湿運転され、図中破線矢印方向に循環させることにより暖房運転される。この四方弁３の切換操作は図示しない室内制御器により制御される。また、圧縮機２、外気温センサ１１、除湿絞り装置７、室温センサ１３には、図中一点鎖線で示す信号線により制御装置１４を電気的に接続している。制御装置１４は後述するように冷暖房運転時に除湿絞り装置７の弁体を開弁させる一方、除湿運転時に、除湿絞り装置７の弁体を閉弁させると共に、外気温と室温との温度差が所定値（例えば１１℃）以上であるときに、除湿絞り装置７の閉弁を所定時間毎（断続的）に開弁させるものである。
【００２１】
図４は上記除湿絞り装置７の閉弁時の概略縦断面図、図５は同開弁時の概略縦断面図である。これらの図に示すように、この除湿絞り装置７は、冷，暖房運転時に弁体を全開して冷媒を低圧力損失の冷媒通路を通すことにより、冷媒を殆ど絞らずにそのまま通過させる一方、除湿運転時には絞り弁として作用する電磁二方弁よりなる。
【００２２】
すなわち、図４，図５に示すように除湿絞り装置７は弁箱１５内に第１，第２の２つの弁室１６，１７を設け、除湿運転時には第１の弁室１６が冷媒の高圧側となり、第２の弁室１７が冷媒の低圧側となる。
【００２３】
この第１の弁室１６には図３で示す第１の室内熱交換器６側の第１の冷媒配管９ａを連通自在に連結する一方、第２の弁室１７には第２の室内熱交換器８側の第２の冷媒配管９ｂを連通自在に連結している。除湿運転時には図４，図５中白矢印に示すように第１の冷媒配管９ａが冷媒の入口管となって第１の弁室１６が高圧側となる一方、第２の冷媒配管９ｂが冷媒の出口管となって第２の弁室１７が低圧側となる。
【００２４】
そして、図４，図５に示すように第１，第２の弁室１６，１７の境界では、第１の弁室１３側に突出した円筒状の弁座部１８を弁箱１２と一体に連成している。この弁座部１８は、その図中上端に弁ポート１９を形成し、この弁ポート１９の内側に弁座１９ａを形成している。したがって、第１，第２の弁室１６，１７とこれらを連通させる弁ポート１９とは冷媒流を殆ど絞らずにそのまま通す低圧力損失冷媒通路に形成される。一方、図６にも示すように弁座１９ａの内周面には第１の弁室１６と第２の弁室１７とを連通させる冷媒絞り通路の一例である複数の切込溝１９ｂを冷媒の流れ方向に平行、かつ弁ポート１９の中心に対して互いに対称位置になるようにそれぞれ設けている。これら切込溝１９ｂは図４に示すように弁体２１が弁座１９ａに着座して弁ポート１９を閉じたときに、第１の弁室１６と第２の弁室１７とを連通させる狭隘な冷媒絞り通路としてそれぞれ形成される。
【００２５】
一方、第１の弁室１６内には弁棒２０を図４，図５中上下方向に移動可能に設け、この弁棒２０の先端部（図４，図５では下端部）には弁棒２０よりも大径の円筒状の弁体２１を一体に連成している。
【００２６】
図４，図５に示すように弁体２１は弁ポート１９よりも若干大きい外径を有する円筒形をなし、その開口先端部には先細のテーパ面２１ａを形成し、この弁体テーパ面２１ａが円錐状弁座１９ａに液密かつ気密に着座して弁ポート１９を閉塞するようになっている。
【００２７】
そして、弁棒２０は、その弁体２１とは軸方向反対側の端部（図４，図５では上端部）に、有底円筒状のプランジャ２２の底部を同心状に一体に形成し、このプランジャ２２の上部開口端部内に励磁ガイド２３の中央突出端部２３ａを同心状に嵌入されるように配置して、プランジャ２２が軸方向（図４では上下方向）に移動する際に、その移動を励磁ガイド２３の中央突出端部２３ａによりガイドすると共に、上端のストッパとして機能するように構成されている。
【００２８】
また、プランジャ２２の底面と、弁箱１５内に固定されたストッパ２４との間において、弁棒２０の外周にコイル状のばね２５を外嵌し、このばね２５のばね力により常時プランジャ２２および弁体２１を図４，図５中上方に押し上げるように付勢されており、励磁ガイド２３の外側にはこの励磁ガイド２３を励磁する励磁コイル２６を設けている。このために、励磁コイル２６の無励磁時にはばね２５のばね力によりプランジャ２２を弁座部１８の反対側（図４では上方）へ押し上げることより、弁ポート１９、すなわち、低圧力損失冷媒通路を常時全開させるようになっている。
【００２９】
図１は上記制御装置１４の除湿運転時の制御プログラムのフローチャートであり、図中Ｓ１〜Ｓ７はフローチャートの各ステップを示す。制御装置１４は例えばマイクロプロセッサよりなり、その機能を図示しない室内制御器に設けてもよい。
【００３０】
まず、図１に示すように制御装置１４は、除湿運転時の制御プログラムを起動してスタートさせると、Ｓ１で、運転モードとして除湿運転モードが選択されているか否かを、例えば図示しないリモートコントローラまたはこのリモートコントローラから運転モード信号を読み出した図示しない室内制御器から繰返し読み出し、除湿運転モードが選択されていると判断したときは、ＹｅｓとしてＳ２で除湿絞り装置７の励磁コイル２６を通電励磁する。すると、励磁ガイド２３とプランジャ２２との間に発生する大きな電磁力により弁体２１をばね２５のばね力に抗して図４中下方へ押し下げて弁座１９ａに着座させて弁ポート１９を閉じる。
【００３１】
これにより、弁ポート１９に連通する低圧力損失の冷媒通路が閉鎖されるので、第１（上流側）の利用熱交換器６で放熱凝縮して液化し除湿絞り装置７の第１の弁室１６に流入した液冷媒が低圧力損失の冷媒通路を通るのを弁体２１により阻止される。
【００３２】
しかし、この弁体２１の閉弁時には、複数の切込溝１９ｂが絞り冷媒通路として弁体２１の外周面と弁座１９の内周面との間にそれぞれ形成され、これら切込溝１９ｂを介して第１の弁室１６と第２の弁室１７とが連通する。このために、上流側の第１の室内熱交換器６内で凝縮して周囲空気（室内空気）に放熱して加熱する一方で液化した液冷媒が除湿絞り弁７の第１の弁室１６内に流入する。すると、この液冷媒は、弁ポート１９を閉鎖中の弁体２１により低圧力損失冷媒通路を通ることが阻止されるので、絞り冷媒通路の各切込溝１９ｂのみを通り、その際に流量と圧力が絞られて第２の弁室１７を経て第２の室内熱交換器８内へ流入し、ここで蒸発して周囲空気を冷却する一方で気化し、ガス状態で四方弁３を経て圧縮機２の吸込口へ戻される。
【００３３】
したがって、第２の室内熱交換器８の冷却作用により周囲空気を除湿する一方で、その冷却作用により冷却した空気を、第１の室内熱交換器６の放熱作用により加熱するので、室内機から室内へ吹き出される空気の温度をあまり下げずに湿度を下げることができる。
【００３４】
次のＳ３でこの除湿絞り装置７の閉弁状態が所定時間、例えば３分間経過したか否か繰返し判断し、３分経過したときには、冷凍サイクルを循環する冷媒流が安定したと判断して、Ｙｅｓとして次のＳ４へ進む。
【００３５】
Ｓ４では制御装置１４が外気温センサ１１から外気温を読み出す一方、室温センサ１３から室温を読み出し、次の（１）式が成立するか否か判断する。
【００３６】
【外１】

【００３７】
この（１）式が成立するとき、すなわちＹｅｓのときは圧縮機２の摺動部等の油膜が薄くなり、図７で示す圧縮機２の潤滑特性が悪化する領域に入ると判断してＳ５へ進み、ＮｏのときはＳ６へ進む。
【００３８】
Ｓ５では、上記Ｓ２で閉じた除湿絞り装置７の弁体２１の断続開閉制御を実行する。すなわち、除湿絞り装置７の弁体２１を所定時間閉弁と開弁とを繰り返す。すなわち、除湿絞り装置７の閉弁状態を続行すると、上述したように圧縮機２への液バック量が増大し、圧縮機２内へ冷媒と共に戻る潤滑油量が不足して圧縮機２の潤滑特性が悪化するので、弁体２１を所定時間閉弁した後は所定時間開弁させる。
【００３９】
この弁体２１の開弁時に、除湿絞り装置７の弁ポート１９が開通し、その弁ポート１９に連通する低圧力損失冷媒通路が開通するので、第１の室内熱交換器６からの液冷媒はこの低圧力損失冷媒通路を通って冷媒の圧力と流量が殆ど絞られずに第２の室内熱交換器８内へ流入し、さらに四方弁３を経て圧縮機２の吸込口へ戻る。したがって、圧縮機２へ戻る冷媒流量が断続的に増加するので、この冷媒中に含有されている潤滑油量を増加させることができる。このために、潤滑油不足による圧縮機２の潤滑特性の悪化を防止ないし抑制することができる。このＳ５の後は再びＳ４へ戻り、Ｓ４以下のステップを繰り返す。すなわち、弁体２１の閉弁が断続的に開弁される。
【００４０】
一方、上記Ｓ４でＮｏのときは、Ｓ６で次の（２）式が成立するか否か判断する。
【００４１】
【外２】
室外温度−室内温度≦１０℃ ……（２）
【００４２】
この（２）式が成立する場合、すなわち、Ｙｅｓの場合には、除湿絞り装置７の弁体２１の閉弁状態を続行しても圧縮機２へ戻る潤滑油量の不足を招く虞が少ないので、次のＳ７で除湿絞り装置７の弁体２１の閉弁を維持続行させる。Ｓ７の後は再びＳ４へ戻り、Ｓ４以下のステップを繰り返す。
【００４３】
図２は本発明の第２実施形態を説明するためのグラフであり、図中、ほぼＵ字状の曲線は外気温（Ｔ０）と室温（Ｔａ）との温度差の軌跡を示し、横軸は時間を示している。この第２の実施形態は除湿絞り装置７の弁体２１の閉弁を断続的に開弁制御する場合に、その開弁時間と閉弁時間とを外気温Ｔ０と室温Ｔａとの温度差Ｔ０−Ｔａに対応して制御装置１４により制御する点に特徴がある。
【００４４】
すなわち、図２に示すように除湿絞り装置７の弁体２１の開閉制御を行うゾーンを、外気温と室温Ｔａとの温度差Ｔ０−Ｔａに基づいて３つのゾーンＡ，Ｂ，Ｃに分割している。例えば、外気温と室温Ｔａとの温度差Ｔ０−Ｔａが１０℃以上である場合は同弁体２１の閉状態を維持し、弁体２１を断続的に開弁させないＡゾーンと、同温度差Ｔ０−Ｔａが１１℃〜１５℃の場合は、弁体２１の閉弁時間を３分間に設定する一方、開弁時間を５分間に設定するＢゾーンと、同温度差Ｔ０−Ｔａが１５℃以上の場合は、弁体２１の閉弁時間を５分間に、開弁時間を５分間にそれぞれ設定するＣゾーンの３つのゾーンにそれぞれ分割している。
【００４５】
そして、これら各ゾーンＡ〜Ｃは温度差Ｔ０−Ｔａが縮小して行く方向にある場合には、その逆に温度差Ｔ０−Ｔａが拡大して行く方向にある場合よりも、その温度差設定範囲を、所定温度、例えば１℃ずつ高くなるように設定している。例えば、Ｂゾーンは温度差Ｔ０−Ｔａが拡大して行く方向にあるときは、その温度差設定範囲が１１℃〜１５℃に設定されるが、温度差Ｔ０−Ｔａが縮小して行く方向にあるときは、その温度差設定範囲は１０℃〜１４℃に設定されている。これと同様に、Ａ，Ｃゾーンも温度差Ｔ０−Ｔａが縮小して行く方向にあるときには、それらの温度差の設定値は１０℃，１４℃以上にそれぞれ設定される。
【００４６】
したがって、この制御方法によれば、除湿絞り弁７の弁体２１の各開閉時間を外気温Ｔ０と室温Ｔａとの温度差Ｔ０−Ｔａに応じた適切な量の潤滑油を圧縮機２内に戻すので、圧縮機２の潤滑特性の最適化を図ることができる。
【００４７】
さらに、外気温Ｔ０と室温Ｔａとの温度差Ｔ０−Ｔａが１０℃以下の場合には、除湿絞り装置７の弁体２１の閉弁維持と共に、圧縮機２の運転周波数を、図示しないインバータを介して所定周波数高くする制御手段を制御装置１４に設けてもよい。
【００４８】
これによれば、圧縮機２から吐出される冷媒吐出流量自体が増加し、冷凍サイクルを循環する冷媒流量が増加するので、除湿絞り装置７の冷媒絞り通路である各切込溝１９ｂにより冷媒流量自体が絞られても、これら切込溝１９ｂを通って圧縮機２へ戻される冷媒流量が増加するので、この冷媒中に含有されている潤滑油量も増加する。このために、圧縮機２の潤滑特性がさらに向上する。
【００４９】
【発明の効果】
以上説明したように本発明によれば、除湿運転時に閉弁される除湿絞り装置の弁体を断続的に開弁させるので、その開弁時に圧縮機へ戻る冷媒流量を増加させることができる。このために、この圧縮機へ戻る冷媒中に含有されている潤滑油量を増加させることができるので、圧縮機の潤滑特性を向上させることができる。
【図面の簡単な説明】
【図１】本発明の第１の実施形態に係る空気調和機の除湿運転制御用プログラムのチャート。
【図２】本発明の第２の実施形態に係る空気調和機の除湿運転制御方法を示すグラフ。
【図３】図１で示す除湿運転制御用プログラムを備えた制御装置を有する空気調和機の冷凍サイクル図。
【図４】図１で示す除湿絞り装置の閉弁状態を示す要部縦断面図。
【図５】図１で示す除湿絞り装置の開弁状態を示す要部縦断面図。
【図６】図５のＶＩ矢視図。
【図７】従来の圧縮機における室外温度（外気温）と室内温度（室温）との温度差と、圧縮機の油膜厚との相対関係を示すグラフ。
【符号の説明】
１空気調和機
２圧縮機
３四方弁
４室外熱交換器
５膨張弁
６第１の室内熱交換器
７除湿絞り装置
８第２の室内熱交換器
９，９ａ，９ｂ冷媒配管
１１外気温センサ
１３室温センサ
１４制御装置
１６第１の弁室
１７第２の弁室
１８弁座部
１９弁ポート
１９ａ弁座
１９ｂ切込溝（冷媒絞り通路）
２０弁棒
２１弁体
２３励磁ガイド
２６励磁コイル[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat pump type air conditioner capable of cooling, heating and dehumidifying operation, and in particular, when the temperature difference between a high outdoor temperature (outdoor temperature) and a low room temperature (indoor temperature) is a predetermined value or more, The present invention relates to an air conditioner in which a valve body of a dehumidifying throttling device that is sometimes closed is intermittently opened to prevent or suppress a decrease in lubrication characteristics of a compressor.
[0002]
[Prior art]
Conventionally, as an example of a heat pump type air conditioner capable of this type of dehumidifying operation, two adjacent two that act as a condenser and an evaporator during the dehumidifying operation in order to realize a dehumidifying control operating cycle such as an isothermal dry cycle. Some refrigerant passages between two indoor heat exchangers are equipped with a dehumidifying throttle device such as a two-way pre-port valve having a throttling function as a dehumidifying throttle valve for throttling the refrigerant. The dehumidifying throttle device includes a valve body that opens and closes a low-loss refrigerant communication path that connects the condenser and the evaporator with a low-loss to the refrigerant flow, a V-groove formed on a joint surface of the valve seat, and the like. In the dehumidifying operation, the valve body is closed to close the low-loss refrigerant passage, and the refrigerant is throttled through the refrigerant throttle passage.
[0003]
[Problems to be solved by the invention]
However, in such a conventional dehumidifying squeezing device, for example, when the outside air temperature (outdoor temperature) is higher than the room temperature (indoor temperature) and the temperature difference is large, the liquid return of the compressor is likely to increase. During operation, the low pressure loss refrigerant passage is always closed by the valve body of the dehumidifying throttle device, and the refrigerant flow rate is always throttled by the refrigerant throttle passage, so that there is a problem that the lubrication characteristics of the compressor deteriorate.
[0004]
That is, in general, when the outside air temperature is high, the high-pressure side pressure of the refrigeration cycle increases, so the discharge refrigerant flow rate in the compressor in the outdoor unit installed outdoors decreases, and the refrigerant flow rate circulating in the refrigeration cycle decreases. On the other hand, when the room temperature is low, the amount of refrigerant evaporated in the evaporator in the indoor unit installed indoors decreases, and the amount of liquid return (liquid back) returning to the compressor in the liquid state increases. Moreover, since the liquid refrigerant has a smaller amount (dilution degree) of lubricating oil than the gaseous refrigerant, when the amount of liquid back is large, the amount of lubricating oil that returns to the compressor together with the refrigerant is insufficient, resulting in poor lubrication characteristics. The problem of getting worse occurs.
[0005]
FIG. 7 shows the relative relationship between the temperature difference between the outside air temperature (outdoor temperature) and the room temperature (indoor temperature) and the thickness of the oil film at a required measurement location such as a sliding portion in the compressor. As shown in FIG. 7, when the temperature difference between the high outside air temperature and the low room temperature is 10 ° C. or more, for example, the thickness of the oil film of the measured portion becomes thin. For example, in the region indicated by the triangle in FIG. This shows the area where the lubrication characteristics of the machine deteriorate.
[0006]
And when the lubrication characteristics of the compressor deteriorate in this way, it is possible to improve the lubrication performance of the compressor by reducing the liquid return by reducing the refrigerant flow rate circulating in the refrigeration cycle, In this method, there is a problem that a new problem such as a decrease in air conditioning capacity due to a decrease in the refrigerant flow rate occurs at the same time.
[0007]
The present invention has been made in consideration of such circumstances, and its purpose is to deteriorate the lubrication characteristics of the compressor when the temperature difference between the high outside air temperature and the low room temperature is larger than a predetermined value during the dehumidifying operation. An object of the present invention is to provide an air conditioner that can improve or improve reliability by preventing or suppressing this.
[0008]
[Means for Solving the Problems]
The invention according to claim 1 of the present application is a first usage-side heat exchanger that is formed by thermally dividing a usage-side heat exchanger that constitutes a refrigeration cycle and that is operated as a condenser and an evaporator during dehumidification operation. And the second use side heat exchanger, the low pressure loss refrigerant passage connecting the first and second use side heat exchangers to the refrigerant flow with low pressure loss, and the low pressure loss refrigerant passage. A valve body that is closed during operation, and a refrigerant throttle passage that is formed so as to connect the first and second usage-side heat exchangers when the low pressure loss refrigerant passage is closed by the valve body and restricts a refrigerant flow. In an air conditioner that includes a dehumidifying throttle device, an outdoor temperature sensor that detects an outdoor temperature, and an indoor temperature sensor that detects a room temperature, the air temperature is higher than the room temperature detected by the room temperature sensor during the dehumidifying operation. Above outdoor temperature A control device is provided that intermittently opens the valve body of the dehumidifying throttle device when the outdoor temperature detected by the sensor is higher and the temperature difference is equal to or greater than a predetermined value. It is an air conditioner.
[0009]
According to the present invention, when the controller detects that the temperature difference between the outdoor temperature (outside air temperature) and the indoor temperature (room temperature) is a predetermined value (for example, 11 ° C.) or more during the dehumidifying operation, The valve body is closed (closed) intermittently (opened) by the control device.
[0010]
For this reason, the liquid refrigerant that has flowed into the dehumidifying throttle device from the first use-side heat exchanger passes through the refrigerant throttle passage only when the valve body is closed, and after the flow rate and pressure are both reduced, It flows into the use side heat exchanger, evaporates here, and returns to the compressor again. Since the flow rate of the refrigerant returned into the compressor is reduced by the dehumidifying throttle valve, the refrigerant flow is reduced and the refrigerant contains a liquid refrigerant with a small amount of lubricating oil. The amount of return to the compressor is reduced.
[0011]
However, after the valve body of the dehumidifying throttle device is closed for a predetermined time, the valve is opened for a predetermined time and the low pressure loss refrigerant passage is opened. It connects via this low pressure loss refrigerant path. For this reason, the refrigerant flow that has flowed into the dehumidification throttle valve from the first use-side heat exchanger flows into the second use-side heat exchanger through the low pressure loss refrigerant passage, with almost no flow rate and pressure being throttled. Then, after evaporating, it is returned to the compressor. Since the flow rate of the refrigerant returned into the compressor is hardly throttled by the dehumidifying throttle device, the refrigerant return amount increases. For this reason, the return amount of the lubricating oil contained in the refrigerant into the compressor also increases. Accordingly, since it is possible to prevent a shortage of the amount of lubricating oil returned to the compressor by repeatedly opening and closing the valve body of the dehumidifying throttle valve thereafter, deterioration of the lubricating characteristics of the compressor can be prevented or reduced.
[0012]
According to a second aspect of the present invention, the control device includes opening / closing time control means for controlling a closing time and an opening time of the valve body of the dehumidifying throttle device according to a difference between the outdoor temperature and the indoor temperature. The air conditioner according to claim 1, wherein the air conditioner is provided.
[0013]
According to this invention, the valve closing time of the valve body of the dehumidifying throttle device that is closed during the dehumidifying operation and the valve opening time that is intermittently opened are determined according to the temperature difference between the outdoor temperature and the indoor temperature. Since the control is performed by the control device, an appropriate amount of lubricating oil corresponding to the temperature difference between the outdoor temperature and the indoor temperature can be returned to the compressor via the refrigerant. For this reason, the lubrication characteristics of the compressor can be improved.
[0014]
According to a third aspect of the present invention, the control device includes compressor control means for increasing the operating frequency of the compressor by a predetermined value when a temperature difference between the outdoor temperature and the indoor temperature is not more than a predetermined value. It is an air conditioner of Claim 1 or 2 characterized by the above-mentioned.
[0015]
According to the present invention, the valve body of the dehumidifying throttle valve that is closed during the dehumidifying operation is intermittently opened as in the invention according to the first aspect, or the dehumidifying throttling apparatus as in the invention according to the second aspect. When the difference between the outdoor temperature and the indoor temperature is below a predetermined value, the compressor operating frequency is increased by a predetermined value to increase the rotation speed. However, the refrigerant flow rate discharged from the compressor can be increased. Thereby, since the refrigerant | coolant flow rate which returns into a compressor increases, the amount of lubricating oil contained in this refrigerant | coolant flow rate can also be increased, and the optimization of the lubrication characteristic of a compressor can be aimed at.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. In these drawings, the same or corresponding parts are denoted by the same reference numerals.
[0017]
FIG. 3 is a refrigeration cycle diagram of the air conditioner 1 according to the embodiment of the present invention.
[0018]
As shown in FIG. 3, the air conditioner 1 includes a compressor 2 whose operation frequency is controlled by an inverter (not shown) and a rotation speed, a four-way valve 3 for switching a channel, an outdoor heat exchanger 4, a decompression unit. An expansion valve 5, which is an example of the device, a first indoor heat exchanger 6 serving as a first use side, a dehumidifying throttle device 7 such as an electromagnetic valve having an on-off valve and a throttling function, and a second use side serving as a second use side The two indoor heat exchangers 8 are sequentially connected in this order by the refrigerant pipe 9 to constitute a closed refrigeration cycle for circulating the refrigerant.
[0019]
The outdoor heat exchanger 4 is provided with an outdoor fan 10 such as a propeller fan that blows outside air to promote heat exchange, and an outdoor unit (not shown) that accommodates the outdoor fan 10 and the outdoor heat exchanger 4 and the like. An outside air temperature sensor 11 for detecting outside air temperature (outdoor temperature) is provided in the case. On the other hand, indoor unit cases (not shown) installed indoors send indoor air to the first and second indoor heat exchangers 6 and 8 and the first and second indoor heat exchangers 6 and 8. While promoting heat exchange, a common indoor fan 12 such as a cross-flow fan that blows heat-exchanged conditioned air into the room and a room temperature sensor 13 that detects room temperature (room temperature) are provided.
[0020]
Further, the refrigeration cycle is cooled or dehumidified by circulating the refrigerant in the direction of the solid arrow in the figure by switching the four-way valve 3, and is heated by circulating in the direction of the broken arrow in the figure. The switching operation of the four-way valve 3 is controlled by an indoor controller (not shown). Further, a control device 14 is electrically connected to the compressor 2, the outside air temperature sensor 11, the dehumidifying and throttling device 7, and the room temperature sensor 13 through a signal line indicated by a one-dot chain line in the drawing. As will be described later, the control device 14 opens the valve body of the dehumidifying throttle device 7 during the cooling and heating operation, while closing the valve body of the dehumidifying throttle device 7 during the dehumidifying operation, and the temperature difference between the outside air temperature and the room temperature is When the temperature is equal to or higher than a predetermined value (for example, 11 ° C.), the valve of the dehumidifying throttle device 7 is opened every predetermined time (intermittently).
[0021]
4 is a schematic longitudinal sectional view when the dehumidifying and throttling device 7 is closed, and FIG. 5 is a schematic longitudinal sectional view when the valve is opened. As shown in these figures, the dehumidifying and throttling device 7 allows the refrigerant to pass through it almost without being squeezed by fully opening the valve body during cooling and heating operation and passing the refrigerant through a low pressure loss refrigerant passage, It consists of an electromagnetic two-way valve that acts as a throttle valve during dehumidifying operation.
[0022]
That is, as shown in FIGS. 4 and 5, the dehumidifying throttle device 7 is provided with the first and second two

valve chambers

16 and 17 in the valve box 15, and the first valve chamber 16 serves as a refrigerant high pressure during the dehumidifying operation. And the second valve chamber 17 is on the low pressure side of the refrigerant.
[0023]
A first refrigerant pipe 9 a on the first indoor heat exchanger 6 side shown in FIG. 3 is connected to the first valve chamber 16 so as to be freely communicated, while a second indoor heat is connected to the second valve chamber 17. The second refrigerant pipe 9b on the exchanger 8 side is connected to be freely communicated. In the dehumidifying operation, as indicated by white arrows in FIGS. 4 and 5, the first refrigerant pipe 9 a serves as an inlet pipe for the refrigerant and the first valve chamber 16 serves as a high-pressure side, while the second refrigerant pipe 9 b serves as a refrigerant. The second valve chamber 17 is on the low pressure side.
[0024]
4 and 5, at the boundary between the first and

second valve chambers

16 and 17, a cylindrical valve seat portion 18 protruding toward the first valve chamber 13 is integrated with the valve box 12. It is coupled. The valve seat portion 18 forms a valve port 19 at the upper end in the figure, and forms a valve seat 19 a inside the valve port 19. Therefore, the first and

second valve chambers

16 and 17 and the valve port 19 for communicating them are formed in a low pressure loss refrigerant passage that allows the refrigerant flow to pass therethrough almost without being throttled. On the other hand, as shown in FIG. 6, the inner peripheral surface of the valve seat 19 a is provided with a plurality of cut grooves 19 b as an example of a refrigerant throttle passage that communicates the first valve chamber 16 and the second valve chamber 17. Are provided so as to be parallel to the flow direction and symmetrical with respect to the center of the valve port 19. As shown in FIG. 4, these cut grooves 19 b are narrow passages that allow the first valve chamber 16 and the second valve chamber 17 to communicate with each other when the valve body 21 is seated on the valve seat 19 a and the valve port 19 is closed. Each is formed as a simple refrigerant throttle passage.
[0025]
On the other hand, a valve rod 20 is provided in the first valve chamber 16 so as to be movable in the vertical direction in FIGS. 4 and 5, and a valve rod is provided at the tip of the valve rod 20 (the lower end in FIGS. 4 and 5). A cylindrical valve body 21 having a diameter larger than 20 is integrally formed.
[0026]
As shown in FIGS. 4 and 5, the valve body 21 has a cylindrical shape having an outer diameter slightly larger than that of the valve port 19, and a tapered tapered surface 21a is formed at the opening tip, and this valve body tapered surface 21a is formed. Is seated on the conical valve seat 19a in a liquid-tight and air-tight manner to close the valve port 19.
[0027]
The valve stem 20 is formed by concentrically and integrally forming the bottom of the bottomed cylindrical plunger 22 at the end opposite to the valve body 21 in the axial direction (the upper end in FIGS. 4 and 5). When the plunger 22 moves in the axial direction (vertical direction in FIG. 4), the central projecting end portion 23a of the excitation guide 23 is disposed so as to be concentrically inserted into the upper opening end portion of the plunger 22. The movement is guided by the central projecting end portion 23a of the excitation guide 23 and functions as a stopper at the upper end.
[0028]
A coiled spring 25 is fitted on the outer periphery of the valve stem 20 between the bottom surface of the plunger 22 and a stopper 24 fixed in the valve box 15. The valve body 21 is urged so as to push upward in FIGS. 4 and 5, and an excitation coil 26 for exciting the excitation guide 23 is provided outside the excitation guide 23. Therefore, when the exciting coil 26 is not excited, the plunger 22 is pushed up to the opposite side (upward in FIG. 4) of the valve seat 18 by the spring force of the spring 25, so that the valve port 19, that is, the low pressure loss refrigerant passage is formed. It is designed to be fully open at all times.
[0029]
FIG. 1 is a flowchart of a control program during the dehumidifying operation of the control device 14, and S1 to S7 in the figure indicate the steps of the flowchart. The control device 14 is formed of, for example, a microprocessor, and the function thereof may be provided in an indoor controller (not shown).
[0030]
First, as shown in FIG. 1, when the control device 14 starts and starts a control program at the time of dehumidifying operation, whether or not the dehumidifying operation mode is selected as the operation mode at S1, for example, a remote controller (not shown) Alternatively, when it is determined that the dehumidifying operation mode is selected by repeatedly reading from an indoor controller (not shown) that has read the operation mode signal from the remote controller, the excitation coil 26 of the dehumidifying throttle device 7 is energized and excited in S2 as Yes. . Then, the valve body 21 is pushed down in FIG. 4 against the spring force of the spring 25 by a large electromagnetic force generated between the excitation guide 23 and the plunger 22 to be seated on the valve seat 19a and the valve port 19 is closed. .
[0031]
As a result, the low pressure loss refrigerant passage communicating with the valve port 19 is closed, so that the heat is condensed and liquefied by the first (upstream side) heat exchanger 6 to be liquefied and the first valve chamber of the dehumidifying throttle device 7. The valve body 21 prevents the liquid refrigerant flowing into the refrigerant 16 from passing through the low pressure loss refrigerant passage.
[0032]
However, when the valve body 21 is closed, a plurality of cut grooves 19b are formed as throttle refrigerant passages between the outer peripheral surface of the valve body 21 and the inner peripheral surface of the valve seat 19, respectively. The first valve chamber 16 and the second valve chamber 17 communicate with each other. For this purpose, the first refrigerant chamber 16 of the dehumidifying throttle valve 7 is cooled while condensing in the first indoor heat exchanger 6 on the upstream side and dissipating heat to the surrounding air (indoor air) and heating. Flows in. Then, since this liquid refrigerant is prevented from passing through the low pressure loss refrigerant passage by the valve body 21 closing the valve port 19, it passes only through the cut grooves 19b of the throttle refrigerant passage, The pressure is squeezed and flows into the second indoor heat exchanger 8 through the second valve chamber 17, where it evaporates and cools the ambient air while being vaporized, and compressed in the gas state through the four-way valve 3. It is returned to the suction port of the machine 2.
[0033]
Therefore, while the ambient air is dehumidified by the cooling action of the second indoor heat exchanger 8, the air cooled by the cooling action is heated by the heat radiation action of the first indoor heat exchanger 6. Humidity can be lowered without significantly reducing the temperature of the air blown into the room.
[0034]
In the next S3, it is repeatedly determined whether or not the valve closing state of the dehumidifying throttle device 7 has passed for a predetermined time, for example, 3 minutes. When 3 minutes have passed, it is determined that the refrigerant flow circulating in the refrigeration cycle is stable, It progresses to following S4 as Yes.
[0035]
In S4, the control device 14 reads the outside air temperature from the outside air temperature sensor 11, while reading the room temperature from the room temperature sensor 13, and determines whether or not the following equation (1) is satisfied.
[0036]
[Outside 1]

[0037]
When this equation (1) is satisfied, that is, Yes, it is determined that the oil film such as the sliding portion of the compressor 2 becomes thin and enters the region where the lubrication characteristics of the compressor 2 shown in FIG. If No, go to S6.
[0038]
In S5, the intermittent opening / closing control of the valve body 21 of the dehumidifying throttle device 7 closed in S2 is executed. That is, the valve body 21 of the dehumidifying and throttling device 7 is repeatedly closed and opened for a predetermined time. That is, when the dehumidifying and throttling device 7 continues to be closed, the amount of liquid back to the compressor 2 increases as described above, and the amount of lubricating oil that returns to the compressor 2 together with the refrigerant is insufficient to lubricate the compressor 2. Since the characteristics deteriorate, the valve element 21 is opened for a predetermined time after being closed for a predetermined time.
[0039]
When the valve body 21 is opened, the valve port 19 of the dehumidifying and throttling device 7 is opened, and the low pressure loss refrigerant passage communicating with the valve port 19 is opened. Therefore, the liquid refrigerant from the first indoor heat exchanger 6 is opened. The refrigerant flows through the low pressure loss refrigerant passage into the second indoor heat exchanger 8 with almost no refrigerant pressure and flow rate, and further returns to the suction port of the compressor 2 through the four-way valve 3. Accordingly, since the refrigerant flow rate returning to the compressor 2 increases intermittently, the amount of lubricating oil contained in the refrigerant can be increased. For this reason, deterioration of the lubrication characteristics of the compressor 2 due to lack of lubricating oil can be prevented or suppressed. After S5, the process returns to S4 again, and the steps after S4 are repeated. That is, the closing of the valve body 21 is intermittently opened.
[0040]
On the other hand, when the result in S4 is No, it is determined in S6 whether or not the following equation (2) is established.
[0041]
[Outside 2]
Outdoor temperature-Indoor temperature ≤ 10 ° C (2)
[0042]
When this formula (2) is satisfied, that is, in the case of Yes, there is little possibility of causing a shortage of the amount of lubricating oil that returns to the compressor 2 even if the valve body 21 of the dehumidifying throttle device 7 is kept closed. Therefore, in the next S7, the valve body 21 of the dehumidifying and throttling device 7 is kept closed. After S7, the process returns to S4 again, and the steps after S4 are repeated.
[0043]
FIG. 2 is a graph for explaining a second embodiment of the present invention. In the figure, a substantially U-shaped curve indicates a locus of a temperature difference between the outside air temperature (T0) and room temperature (Ta), and the horizontal axis Indicates time. In the second embodiment, when valve closing control of the valve element 21 of the dehumidifying and throttling device 7 is intermittently performed, the valve opening time and the valve closing time are set to a temperature difference T0 between the outside air temperature T0 and the room temperature Ta. It is characterized in that it is controlled by the control device 14 corresponding to -Ta.
[0044]
That is, as shown in FIG. 2, the zone for performing opening / closing control of the valve element 21 of the dehumidifying throttle device 7 is divided into three zones A, B, and C based on the temperature difference T0-Ta between the outside air temperature and the room temperature Ta. ing. For example, when the temperature difference T0−Ta between the outside air temperature and the room temperature Ta is 10 ° C. or more, the valve body 21 is kept closed and the valve body 21 is not intermittently opened, and the same temperature difference. When T0-Ta is 11 ° C. to 15 ° C., the valve closing time of the valve element 21 is set to 3 minutes, while the B zone in which the valve opening time is set to 5 minutes and the temperature difference T0-Ta is 15 ° C. In the above case, the valve element 21 is divided into three zones, C zone, in which the valve closing time is set to 5 minutes and the valve opening time is set to 5 minutes.
[0045]
And, in each of these zones A to C, when the temperature difference T0-Ta is in the direction of decreasing, the temperature difference setting is more conversely than when the temperature difference T0-Ta is in the direction of increasing. The range is set to be higher by a predetermined temperature, for example, 1 ° C. For example, when the zone B is in the direction in which the temperature difference T0-Ta increases, the temperature difference setting range is set to 11 ° C. to 15 ° C., but in the direction in which the temperature difference T0-Ta decreases. In some cases, the temperature difference setting range is set to 10 ° C to 14 ° C. Similarly, when the temperature difference T0-Ta is also in the direction of decreasing, the A and C zones are set to 10 ° C. and 14 ° C. or more, respectively.
[0046]
Therefore, according to this control method, an appropriate amount of lubricating oil corresponding to the temperature difference T0-Ta between the outside air temperature T0 and the room temperature Ta is set in the compressor 2 for each opening / closing time of the valve body 21 of the dehumidifying throttle valve 7. Therefore, the lubrication characteristics of the compressor 2 can be optimized.
[0047]
Further, when the temperature difference T0-Ta between the outside air temperature T0 and the room temperature Ta is 10 ° C. or less, the valve body 21 of the dehumidifying and throttling device 7 is kept closed and the operation frequency of the compressor 2 is changed to an inverter (not shown). The control device 14 may be provided with control means for increasing the frequency by a predetermined frequency.
[0048]
According to this, since the refrigerant discharge flow rate discharged from the compressor 2 itself increases and the refrigerant flow rate circulating in the refrigeration cycle increases, the refrigerant flow rate is set by the cut grooves 19b which are the refrigerant throttle passages of the dehumidifying throttle device 7. Even if it is squeezed, the flow rate of the refrigerant returned to the compressor 2 through the cut grooves 19b increases, so that the amount of lubricating oil contained in the refrigerant also increases. For this reason, the lubrication characteristics of the compressor 2 are further improved.
[0049]
【The invention's effect】
As described above, according to the present invention, the valve body of the dehumidifying throttle device that is closed during the dehumidifying operation is intermittently opened, so that the refrigerant flow rate returning to the compressor when the valve is opened can be increased. For this reason, since the amount of lubricating oil contained in the refrigerant returning to the compressor can be increased, the lubricating characteristics of the compressor can be improved.
[Brief description of the drawings]
FIG. 1 is a chart of a dehumidifying operation control program for an air conditioner according to a first embodiment of the present invention.
FIG. 2 is a graph showing a dehumidifying operation control method for an air conditioner according to a second embodiment of the present invention.
FIG. 3 is a refrigeration cycle diagram of an air conditioner having a control device including the dehumidifying operation control program shown in FIG.
4 is a longitudinal sectional view of a main part showing a valve closing state of the dehumidifying throttle device shown in FIG. 1. FIG.
5 is a longitudinal sectional view of a main part showing a valve opening state of the dehumidifying and throttling device shown in FIG. 1. FIG.
6 is a view taken along arrow VI in FIG. 5;
FIG. 7 is a graph showing a relative relationship between a temperature difference between an outdoor temperature (outside air temperature) and an indoor temperature (room temperature) in a conventional compressor and an oil film thickness of the compressor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Air conditioner 2 Compressor 3 Four-way valve 4 Outdoor heat exchanger 5 Expansion valve 6 First indoor heat exchanger 7 Dehumidifying throttling device 8 Second

indoor heat exchangers

9, 9a, 9b Refrigerant piping 11 Outside air temperature sensor 13 Room temperature sensor 14 Controller 16 First valve chamber 17 Second valve chamber 18 Valve seat portion 19 Valve port 19a Valve seat 19b Cut groove (refrigerant throttle passage)
20 Valve stem 21 Valve body 23 Excitation guide 26 Excitation coil

Claims

A first use side heat exchanger and a second use side heat exchanger, which are divided into two thermally by the use side heat exchanger constituting the refrigeration cycle and are operated as a condenser and an evaporator during dehumidification operation, respectively. When,
A low pressure loss refrigerant passage that connects the first and second use side heat exchangers to the refrigerant flow with low pressure loss, a valve body that closes the low pressure loss refrigerant passage during dehumidification operation, and the valve body A dehumidifying squeezing device comprising a refrigerant squeezing passage formed to connect the first and second usage-side heat exchangers when the low pressure loss refrigerant passage is closed;
An outdoor temperature sensor for detecting the outdoor temperature;
An indoor temperature sensor for detecting the indoor temperature;
In an air conditioner equipped with
The valve body of the dehumidifying throttle device when the outdoor temperature detected by the outdoor temperature sensor is higher than the indoor temperature detected by the indoor temperature sensor during the dehumidifying operation and the temperature difference is not less than a predetermined value. An air conditioner provided with a control device that intermittently opens the valve.

The control device includes opening / closing time control means for controlling a closing time and an opening time of a valve body of the dehumidifying throttle device according to a difference between the outdoor temperature and the indoor temperature. The air conditioner according to claim 1.

The said control apparatus is equipped with the compressor control means which makes the operating frequency of the said compressor high predetermined value when the temperature difference of the said outdoor temperature and the said indoor temperature is below a predetermined value, It is characterized by the above-mentioned. The air conditioner according to 1 or 2.