JP3909520B2

JP3909520B2 - Cooling system

Info

Publication number: JP3909520B2
Application number: JP2002250172A
Authority: JP
Inventors: 多佳志岡崎; 晋亀山; 康文畑村; 嘉夫上野; 弘滝
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2002-08-29
Filing date: 2002-08-29
Publication date: 2007-04-25
Anticipated expiration: 2022-08-29
Also published as: JP2004085151A

Description

【０００１】
【発明の属する技術分野】
本発明は冷媒自然循環による冷却運転を利用する冷却装置に関するものであり、特に起動時などに液冷媒がガス配管を逆流して逆循環が発生するのを防止する構造に関する。
【０００２】
【従来の技術】
近年、移動体通信の中継電子機器を納めた通信基地局に代表されるような電子機器の発熱を除去する分野が急速に広がっており、これらの場所では年間を通しての冷却運転が必要となっている。
これらの用途では、冬季、夜間のように外気温度が低い場合には、換気によって冷房することも可能であるが、霧、雨、雪、塵埃の侵入を防ぐ装置が必要となり、しかも外気温度の変動によって室内温度も変動するため安定した冷却が行えない。
この様な条件では、室内温度と外気温度との温度差を利用して、室内から室外へ冷媒により熱を運ぶ冷媒自然循環を利用した冷却装置を用いることができる。この冷媒自然循環を利用した冷却装置は、通常の蒸気圧縮式の冷却装置よりも年間消費電力を大幅に低減することができる。
【０００３】
ところで、冷媒自然循環（以下，自然循環という）を利用した冷却装置の例としては、特開平９−２４３１１１号公報に開示のものが知られている。
図１２はかかる公報に開示の従来の冷却装置の構成を示す模式図である。
従来の冷房装置は，２つの冷媒回路を有している。１つの冷媒回路は、冷却器１００、ガス配管１０１、熱交換器１０２、液配管１０３の順に冷媒が循環する自然循環回路１０４であり、他の冷媒回路は、コンデンシングユニット２００、液配管２０１、膨張弁２０２、熱交換器１０２、ガス配管２０３の順に冷媒が循環する冷却補助回路２０４である。
【０００４】
このうち、自然循環回路１０４はビル内に縦にめぐらされた回路であり、この回路内の冷媒によりビルの室内が冷房される。すなわち、冷却器１００は室内に配置され，ファン１０５は冷却器１００に室内空気を当てて効果的な冷房を行うものである。
熱交換器１０２は自然循環回路１０４の上端部に、ガス配管１０１との接続口を上にし、液配管１０３との接続口を下にして、鉛直に配置される。通常、熱交換器１０２はコンデンシングユニット２００など冷却補助回路２０４の他の構成要素とともに、ビル最上部に設置される。
冷却補助回路２０４は、コンデンシングユニット２００に圧縮機と凝縮器とを有し、一般的に知られた蒸気圧縮冷凍サイクルである。自然循環回路１０４と冷却補助回路２０４とは、異なる冷媒回路系であるが、熱交換器１０２において熱交換が行われ，自然循環回路１０４に対しては凝縮器として機能し、冷却補助回路２０４に対しては蒸発器（冷却器）として機能する。
【０００５】
次に，従来の冷却装置の動作を説明する。
自然循環回路１０４の冷媒は，冷却器１００において蒸発・気化し冷媒ガスとなる。冷却器１００において発生した冷媒ガスは、ガス配管１０１を通って、冷却器１００から熱交換器１０２に導かれる。この冷媒ガスは熱交換器１０２において、冷却補助回路２０４の冷媒液（湿り蒸気）と熱交換して冷却され凝縮・液化される。
熱交換器１０２は鉛直に配置されているので、液化された自然循環回路１０４の冷媒は、重力により熱交換器１０２内を流下する。凝縮した液冷媒は，下部の液配管１０３との接続口から流出し，液配管１０３を通って冷却器１００に再び供給される。
【０００６】
上述のように、熱交換器１０２が鉛直に配置されていることにより、熱交換器１０２内の冷媒液の流れは必ず下向きとなり、冷媒ガスが常にガス配管１０１を上昇する向きに冷媒が循環する。もしも冷媒の循環が逆転したならば、冷媒ガスは液配管１０３を上昇することとなり、冷媒ガスの圧力損失によって、冷媒の循環速度が所期の値よりも減少して冷却能力が低下するが，従来の冷房装置は，常に正しい方向に冷媒が循環するので、所期の高い冷却能力を安定して発揮することができるというものである。
【０００７】
【発明が解決しようとする課題】
従来の自然循環回路を備えた冷却装置は，熱交換器１０２を自然循環回路１０４の上端部に，ガス配管１０１との接続口を上にし，液配管１０３との接続口を下にして，鉛直に配置する構成であるが，プレートフィン型熱交換器を自然循環回路に用いる場合，一般に熱交換器は複数の冷媒流路とそれらの冷媒流路が接続される分岐管および合流管を有しており，それらとガス配管および液配管の接続構造については冷媒の逆循環の発生を防止するという点が考慮されていないという課題があった。
また，従来の冷却装置は，熱交換器１０２を鉛直に配置する構成であるが，冷媒流路が水平に配置される場合についても冷媒の逆循環の発生を防止するという点が考慮されていないという課題があった。
【０００８】
本発明は上記のような従来の課題を解決するためになされたもので、冷媒自然循環を用いる冷却装置において，起動時などに液冷媒がガス配管を逆流して逆循環が発生するのを防止できる安価で簡素な構成の冷却装置を提供することを目的とするものである。
【０００９】
【課題を解決するための手段】
この発明の請求項１に係わる冷却装置は、少なくとも凝縮器，液配管，蒸発器及びガス配管を順次接続して冷媒回路を構成し，前記凝縮器を前記蒸発器よりも高所に設置するとともに、前記液配管および前記ガス配管を傾斜させて配置して冷媒自然循環により冷却運転を行う冷却装置において，前記凝縮器が複数の冷媒流路を有するプレートフィンチューブ型熱交換器で構成され，前記複数の冷媒流路の流入管及び流出管がそれぞれ第１の分岐管及び第１の合流管に接続されると共に，前記ガス配管が冷媒流れ方向に下り勾配部を設けて前記第１の分岐管の上方に接続され、前記蒸発器が複数の冷媒流路を有するプレートフィンチューブ型熱交換器で構成され，前記複数の冷媒流路の流入管および流出管がそれぞれ第２の分岐管及び第２の合流管に接続されると共に，前記液配管が冷媒流れ方向に上り勾配部を設けて前記第２の分岐管の下方に接続され、前記第１の合流管の下方から略垂直の下り勾配部を設けて前記傾斜した液配管を接続すると共に，第２の合流管の上方から略垂直の上り勾配部を設けて前記傾斜したガス配管を接続することを特徴とするものである。
【００１０】
この発明の請求項２に係わる冷却装置は，前記構成に加え，前記ガス配管の下り勾配部の最高位置を前記凝縮器の最高位置よりも２０ｍｍ以上高くする構成と，前記液配管の上り勾配部の最低位置を前記蒸発器の最低位置よりも２０ｍｍ以上低くする構成とを有することを特徴とするものである。
【００１１】
この発明の請求項３に係わる冷却装置は，前記構成に加え，前記凝縮器における複数の冷媒流路及び前記蒸発器における複数の冷媒流路の少なくとも一方が，列方向が垂直となるように配置されると共に，段方向が水平となるように配置されることを特徴とするものである。
【００１２】
この発明の請求項４に係わる冷却装置は，少なくとも凝縮器，液配管，蒸発器及びガス配管を順次配管で接続して冷媒回路を構成し，前記凝縮器を前記蒸発器よりも高所に設置して冷媒自然循環により冷却運転を行う冷却装置において，前記凝縮器が複数の冷媒流路を有するプレートフィンチューブ型熱交換器で構成されるとともに、前記複数の冷媒流路の列方向が垂直に配置され、段方向が水平に配置され，前記複数の冷媒流路の流入管及び流出管がそれぞれ第１の分岐管及び第１の合流管に接続されると共に，前記流入管が第１の分岐管の下方から冷媒の流れ方向に下り勾配部を設けて前記凝縮器の入口部に接続され，前記流出管が前記凝縮器の出口部から冷媒の流れ方向に下り勾配部を設けて第１の合流管の上方に接続され，前記第１の分岐管を前記凝縮器の最高位置よりも高所に，前記第１の合流管を前記凝縮器の最低位置よりも低所に設置し、前記蒸発器が複数の冷媒流路を有するプレートフィンチューブ型熱交換器で構成されるとともに、前記複数の冷媒流路の列方向が垂直に配置され、段方向が水平に配置され，前記複数の冷媒流路の流入管及び流出管がそれぞれ第２の分岐管及び第２の合流管に接続されると共に，前記流入管が第２の分岐管の上方から冷媒の流れ方向に上り勾配部を設けて前記蒸発器の入口部に接続され，
前記流出管が前記蒸発器の出口部から冷媒の流れ方向に上り勾配部を設けて第２の合流管の下方に接続され，前記第２の分岐管を前記蒸発器の最低位置よりも低所に，前記第２の合流管を前記蒸発器の最高位置よりも高所に設置するようにしたことを特徴とするものである。
【００１３】
この発明の請求項５に係わる冷却装置は，前記蒸発器の近傍に蒸気圧縮式冷凍サイクル装置の蒸発器を配置したことを特徴とするものである。
【００１４】
この発明の請求項６に係わる冷却装置は，前記蒸発器出口と前記凝縮器入口とを接続する前記ガス配管に第１開閉弁を設け、該ガス配管で該第１開閉弁より前記凝縮器側に圧縮機を接続し、前記凝縮器出口と前記蒸発器入口とを接続する前記液配管に膨張弁を設け、該膨張弁をバイパスする配管に第２開閉弁を設け、前記圧縮機，凝縮器，膨張弁及び蒸発器の経路で冷凍サイクルを構成し，前記第１開閉弁及び第２開閉弁を開閉することにより，圧縮機運転による強制循環運転と圧縮機停止による自然循環運転とを切り換え可能に構成したことを特徴とするものである。
【００１８】
【発明の実施の形態】
実施の形態１（参考例）．
図１はこの発明の実施形態１に係る冷却装置の構成を示す模式図、図２は同冷却装置の凝縮器の構成を示す斜視図、図３は同冷却装置の逆循環が生じる原理を示す模式図である。
図１に示すように、凝縮器１及び蒸発器２とそれらを接続するための液配管３及びガス配管４から構成されている。
凝縮器１には，複数の流入管１２及び流出管９が接続され，流入管１２の他端は第１の分岐管８に接続され，流出管９の他端は第１の合流管５に接続されている。同様に，蒸発器２には，複数の流入管１０及び流出管１１が接続され，流入管１０の他端は第２の分岐管６に接続され，流出管１１の他端は第２の合流管７に接続されている。
【００１９】
また，第１の合流管５と第２の分岐管６は液配管３で接続され，第１の分岐管８と第２の合流管７は第１の分岐管８の上方に接続される冷媒流れ方向の下り勾配部１３を設けた逆Ｕ字型配管２０を介してガス配管４で接続されている。ここで，上り勾配や下り勾配の定義は，冷媒が正方向に自然循環する場合の冷媒流れ方向（凝縮器１，液配管３，蒸発器２，ガス配管４の順に冷媒が循環）に対する勾配を意味するものとする。
この逆Ｕ字型配管２０は，その最高位置が凝縮器１の最高位置に対して２０ｍｍ以上高く設定されている。
また，凝縮器１には室外送風機４０が，蒸発器２には室内送風機４１が備えられており，凝縮器１の外表面へ室外空気が，蒸発器２の外表面へ室内空気が強制的に供給される。なお，凝縮器１は蒸発器２よりも高所に設置されており，凝縮器１上面と蒸発器２下面は，例えば数十ｃｍ程度の高低差を設けて設置されている。
【００２０】
図２において、凝縮器１は，プレートフィン３０と流入管１２，流出管９等のチューブ（伝熱管）から構成されるプレートフィンチューブ型熱交換器であり，列方向が垂直に，段方向が水平に配置される。
また，複数の流入管１２が第１の分岐管８に，複数の流出管９が第１の合流管５に接続され，流入管１２と流出管９を両端とする複数の冷媒流路は水平に配置されると共に，第１の分岐管８及び第１の合流管５も水平に配置されている。第１の分岐管８の上方には，冷媒流れ方向に下り勾配部１３を備えた逆Ｕ字型配管２０が接続され，管端部３１でガス配管４に接続されている。
また，第１の合流管５には，冷媒流れ方向に下り勾配を備えた直管が接続され，管端部３２で液配管３に接続されている。
なお，流入管１２や流出管９などの伝熱管は例えば６ｍｍ〜１３ｍｍ程度のものが，分岐管８，合流管５，液配管３，ガス配管４は例えば９ｍｍ〜２０ｍｍ程度のものが使用される。
【００２１】
上記のように構成されたこの発明の実施の形態１に係る冷却装置の運転動作を図１に基づいて説明する。
この冷却装置は例えば年間を通して冷却が必要な場所に利用され、室内温度が外気温度よりも高い場合に室内と外気との温度差を利用して冷媒自然循環による冷却運転を行う。
自然循環運転では、凝縮器１で凝縮した液冷媒が複数の流出管９より流出して第１の合流管５に合流し，液配管３を下降する。液配管３を下降した液冷媒は，第２の分岐管６で複数の流入管１０に分岐され，蒸発器２に流入する。
蒸発器２で蒸発したガス冷媒は、流出管１１より流出して第２の合流管７に合流し，ガス配管４を上昇する。ガス配管４を上昇した冷媒は，逆Ｕ字型配管２０を通って下り勾配部１３を下降し，第１の分岐管８で複数の流入管１２に分岐され，凝縮器１に戻ることで自然循環サイクルが形成される。
【００２２】
ここで，起動時や室内温度低下防止のため室外送風機４０を停止すると，冷媒が逆に循環する場合が生じる。この原理について図３を用いて説明する。
図３において，（ａ）は，室内送風機４１が運転され，室外送風機４０が停止された状態，（ｂ）は（ａ）の状態から室外送風機４１を起動した状態，（ｃ）は（ｂ）の状態から逆循環が発生した状態を示している。また，凝縮器１及び蒸発器２内の黒塗りは冷媒液を示している。
図３の（ａ）に示すように室外送風機４０の停止状態では，凝縮器１での凝縮量が非常に小さく，冷媒は主に蒸発器２内に存在する。この状態で室外送風機４０を起動すると，（ｂ）に示すように凝縮器１での熱交換性能が増加して圧力が低下するため，冷媒は蒸発器２から凝縮器１に液配管３及びガス配管４を通って移動する。
【００２３】
この冷媒移動がほぼ終了した段階（冷媒回路内がほぼ均圧した段階）で，（ｃ）に示すように液配管３がガス冷媒のみとなり，ガス配管４に液冷媒が取り残された状態が発生すると，取り残された液冷媒がガス配管４から蒸発器２へ逆流する。蒸発器２に逆流した液冷媒は，蒸発器２内で蒸発して冷媒ガスとなるため，圧力が上昇し，凝縮器１から液冷媒が流下（正方向に循環）するのを妨げる。
この逆循環現象は，ガス配管４内に存在する液冷媒が蒸発器２及び凝縮器１内に存在する液冷媒と繋れば常に循環駆動力となる液ヘッドが生じて継続的に発生することになる。
なお，この逆循環現象は，室外送風機４０の停止時における蒸発器２内の冷媒量の分布状態（偏在）に依存し，この分布状態は蒸発器２を内蔵する図示しない室内ユニットの吸込み空気の温度分布などに依存する。
【００２４】
本実施の形態１では，第１の分岐管８の上方に，冷媒流れ方向の下り勾配部１３を備えた逆Ｕ字型配管２０が接続されており，ガス配管４に液冷媒が取り残された状態となる場合でも，逆Ｕ字型配管２０により液冷媒が途切れ、送循環駆動力である液ヘッドを切断して継続的な逆循環を防止することができる。
また，逆Ｕ字型配管２０の最高位置を凝縮器１の最高位置に対して２０ｍｍ以上高くしているため，凝縮器１の最高位置の伝熱管内が飽和液で満たされる場合でも逆Ｕ字型配管２０内をガス冷媒で満たすことができ，確実に逆循環を防止することが可能な冷却装置を提供することができる。
【００２５】
また，本実施の形態１では，第１の分岐管８の上方に，冷媒流れ方向の下り勾配部１３を備えた逆Ｕ字型配管２０が接続される構成を示したが，図４に示すように下り勾配部１３を備えた逆Ｖ字型配管２０で構成しても同様の効果を発揮することは勿論である。
【００２６】
さらに，本実施の形態１では，凝縮器１における複数の冷媒流路と蒸発器における複数の冷媒流路が水平に配置され，第１及び第２の合流管５，７と第１及び第２の分岐管８，６も水平に配置されているため，冷却装置が設置される通信基地局などに地上からの高さ制約がある場合にも，冷媒自然循環に必要な高低差を確保でき，かつ蒸発器２下面から凝縮器１上面までの高さを低く抑えることができるため，冷却装置を小型化できるという効果がある。
【００２７】
実施の形態２（参考例）．
図５はこの発明の実施の形態２に係る冷却装置の構成を示す模式図である。
本実施の形態２における冷却装置において，実施の形態１と同構成については同一符号を付し，詳細な説明を省略する。
本実施の形態２において，実施の形態１と異なる構成は，液配管３と第２の分岐管６の間にも冷媒流れ方向に上り勾配部１４を備えたＵ字型配管２１が設けられ，そのＵ字型配管２１が第２の分岐管６の下方に接続されている点である。
このＵ字型配管２１は，その最低位置が蒸発器２の最低位置よりも２０ｍｍ以上低く設定されている。
【００２８】
本実施の形態２では，実施の形態１の効果に加え，第２の分岐管６の下方に，冷媒流れ方向に上り勾配部１４を設けたＵ字型配管２１が接続されているため，上り勾配１４内が常に液冷媒で満たされ，蒸発器２内で蒸発したガス冷媒の逆流を防止でき，常に流出管１１へガス冷媒を供給して逆循環を防止することができる。
また，Ｕ字型配管２１の最低位置を蒸発器２の最低位置よりも２０ｍｍ以上低くしているため，蒸発器２の最低位置の伝熱管内がガス冷媒で満たされる場合でもガス冷媒の逆流を抑制し，確実に逆循環を防止することができる冷却装置を提供することができる。
【００２９】
実施の形態３．
図６はこの発明の実施の形態３に係る冷却装置の構成を示す模式図、図７は同冷却装置の凝縮器の構成を示す斜視図である。
本実施の形態３の冷却装置において，実施の形態２と同構成については同一符号を付し，詳細な説明を省略する。
本実施の形態３において，実施の形態２と異なる構成は，第１の合流管５と液配管３との間に第１の合流管５の下方に接続される冷媒流れ方向の下り勾配部１５を設けると共に，第２の合流管７とガス配管４の間にも第２の合流管７の上方に接続される冷媒流れ方向の上り勾配部１６を設けた点である。
【００３０】
図７に示す凝縮器１は実施の形態１と異なり，第１の合流管５の下方に，冷媒流れ方向に下り勾配部１５を備えたＬ字型配管が接続され，管端部３２で液配管３に接続される。
【００３１】
本実施の形態３では，実施の形態２の効果に加え，第１の合流管５の下方に冷媒流れ方向に下り勾配部１５を設けたため，第１の合流管５に合流した液冷媒を重力により確実に液配管３へ流下させることができ，液冷媒の逆循環を防止することができる。
また，第２の合流管７の上方に冷媒流れ方向に上り勾配１６を設けたため，第２の合流管７に合流したガス冷媒を確実にガス配管４へ流入させることができ，ガス冷媒の逆循環を防止することができる。
【００３２】
実施の形態４．
図８はこの発明の実施の形態４に係る冷却装置の構成を示す模式図である。
本実施の形態４の冷却装置において，実施の形態３と同構成については同一符号を付し，詳細な説明を省略する。
本実施の形態４において，実施の形態３と異なる構成は，ガス配管４と第１の分岐管８との間に設けらた逆Ｕ字型配管２０及び液配管３と第２の分岐管６との間に設けられたＵ字型配管２１並びに第１の合流管５と液配管３との間に設けられた冷媒流れ方向の下り勾配部１５及び第２の合流管７とガス配管４との間に設けられた冷媒流れ方向の上り勾配部１６の代わりに、ガス配管４に接続された第１の分岐管８の下方に冷媒流れ方向の下り勾配部２２を備えた流入管１２が接続され，第１の合流管５の上方に冷媒流れ方向の下り勾配部２３を備えた流出管９が接続され，液配管３に接続された第２の分岐管６の上方に冷媒流れ方向の上り勾配部２４を備えた流入管１０が接続され，第２の合流管７の下方に冷媒流れ方向の上り勾配部２５を備えた流出管１１が接続される点である。
また，上記下り勾配２２，２３や上り勾配２４，２５を設けたことにより，第１の分岐管８は凝縮器１の最高位置よりも高所に，第１の合流管５は凝縮器１の最低位置よりも低所に，第２の分岐管６は蒸発器２の最低位置よりも低所に，第２の合流管７は蒸発器２の最高位置よりも高所に設置されている。
【００３３】
本実施の形態４では，第１の分岐管８が凝縮器１の最高位置よりも高所となるように第１の分岐管８の下方に冷媒流れ方向の下り勾配部２２を設けたため，実施の形態１と同様に液冷媒の逆流を防止することができる。
また，第１の合流管５が凝縮器の最低位置よりも低所となるように第１の合流管５の上方に冷媒流れ方向の下り勾配部２３を設けたため，実施の形態３と同様に凝縮器１で凝縮した液冷媒を確実に第１の合流管５に供給でき，液冷媒の逆循環を防止することができる。
また，第２の分岐管６が蒸発器２の最低位置よりも低所となるように第２の分岐管６の上方に冷媒流れ方向の上り勾配部２４を設けたため，実施の形態２と同様に蒸発器２で蒸発したガス冷媒の逆流を防止することができる。
また，第２の合流管７が蒸発器２の最高位置よりも高所となるように第２の合流管７の下方に冷媒流れ方向の上り勾配部２５を設けたため，実施の形態３と同様に蒸発器２で蒸発したガス冷媒を確実に第２の合流管７に流入させ，ガス冷媒の逆循環を防止することができる。
【００３４】
なお，第１の分岐管８を凝縮器１の最高位置よりも２０ｍｍ以上高所に，第１の合流管５を凝縮器１の最低位置よりも２０ｍｍ以上低所に，第２の分岐管６を蒸発器２の最低位置よりも２０ｍｍ以上低所に，第２の合流管７を蒸発器２の最高位置よりも２０ｍｍ以上高所に設置すれば，実施の形態１および実施の形態２と同様の効果を発揮することは言うまでもない。
【００３５】
実施の形態５．
図９はこの発明の実施の形態５に係る通信基地局５０に設置された冷却装置を示す構成図である。
冷媒自然循環を用いる冷却装置が，圧縮機を用いる蒸気圧縮式冷凍サイクル装置と併用して用いられる例を示している。
図９に示すように、室外ユニット５３は通信基地局５０の外壁上部に室外ユニット支持台５２によって固定され，室内ユニット５４と室外ユニット５３は，ガス配管４及び液配管３により接続されている。また，通信基地局５０には，発熱体である通信機器５８と室内ユニット５４が収納され，通信機器５８からの発熱が室内ユニット５４によって冷却される。
図９において，５１ａは室外ユニット吸込み口、５１ｂは室外ユニット吹出し口，５５ａは室内ユニット吸込み口、５５ｂは室内ユニット吹出し口である。
【００３６】
室内ユニット５４内には，自然循環サイクルおよび蒸気圧縮式サイクルに対応した２つの蒸発器２及び蒸発器５７が収納され，通信機器５８の発熱負荷を冷却する。また，室内空気を強制的に蒸発器２および蒸発器５７の外表面に送風するための室内送風機４１，蒸発器２及び蒸発器５７の吸込み側空間と吹き出し側空間とをそれぞれ仕切る仕切り板５６ａ及び５６ｂより構成されている。
また、室外ユニット５３は、凝縮器１、室外送風機４０より構成され，第１の分岐管８とガス配管４との間には，凝縮器１で凝縮した液冷媒の逆流を防止するための逆Ｕ字型配管２０が設けられると共に，第２の分岐管６と液配管３との間には，蒸発器２で蒸発したガス冷媒の逆流を防止するためのＵ字型配管２１が設けられている。
また，圧縮機を用いる蒸気圧縮式冷凍サイクルの室外ユニット５９は通信基地局５０の横に設置され，蒸発器５７と配管で接続されている。
なお、室外ユニット５３の凝縮器１は室内ユニット５４の蒸発器２よりも高所に配置されており、ここでは例えば５０ｃｍ程度の高低差を設けて配置している。
【００３７】
次に、本実施の形態５における冷却装置の運転動作について説明する。
この冷却装置は，室内温度が外気温度よりも高い場合に室内と外気との温度差を利用して冷媒自然循環による冷却運転を行う。
自然循環運転では、凝縮器１で凝縮した液冷媒が液配管３を下降し、Ｕ字型配管２１を通って蒸発器２に流入する。蒸発器２で蒸発したガス冷媒は、ガス配管４を上昇し，逆Ｕ字型配管２０を通って凝縮器１に戻ることで自然循環サイクルが形成される。
【００３８】
本実施の形態５では，圧縮機を用いる蒸気圧縮式の冷凍サイクル装置と併用される冷却装置において，第１の分岐管８とガス配管４との間に液冷媒の逆流を防止するための逆Ｕ字型配管２０を設けると共に，第２の分岐管６と液配管３との間にガス冷媒の逆流を防止するためのＵ字型配管２１を設けたため，確実に冷媒の逆循環を防止することができる。
また，蒸気圧縮式冷凍サイクル装置を設けたので、自然循環運転だけでは冷却能力が不足する発熱負荷に対しても蒸気圧縮式冷凍サイクル装置によって対応可能な冷却装置を提供することができる。
【００３９】
実施の形態６．
図１０はこの発明の実施の形態６による冷却装置の構成を示す模式図、図１１は同冷却装置の凝縮器を示す斜視図である。
この冷却装置は，通信基地局や電算機室などの扉や壁などに設置され，凝縮器１，蒸発器２，液配管３，ガス配管４を共用し，圧縮機による蒸気圧縮式の冷凍サイクル装置と自然循環サイクルを切り換えて通信機器などの発熱を冷却する冷却装置である。
図１０において，６０は冷却装置の筐体，６１はガス配管４に逆止弁６６を介して接続された圧縮機，６２はガス配管４に開閉弁６５を介して接続されたアキュムレータ，６３は液配管３中に設けられた絞り装置として例えば電子式膨張弁，６４はガス配管４中に設けられた第１開閉弁である逆止弁，６７は液配管３に接続され、電子式膨張弁６３をバイパスする配管に設けられた第２開閉弁であり，実施の形態５と同構成については同一符号を付し，詳細な説明を省略する。
【００４０】
本実施の形態６による冷却装置は，筐体６０内部が仕切り板６８によって室外空間７０と室内空間７１に分離されている。
その室外空間７０内には、冷媒ガスを圧縮するための圧縮機６１、この冷媒ガスを冷却・液化させるための凝縮器１、室外送風機４０、凝縮器１を出た高温高圧の冷媒液を減圧して二相状態の湿り蒸気とする電子式膨張弁６３、過渡的現象や冷媒の過充填などの場合に圧縮機６１への液戻りを防止するためのアキュムレータ６２、圧縮機６１及びアキュムレータ６２をバイパスするための開閉弁６５とガス配管４中に設けられた第１開閉弁である逆止弁６４、自然循環運転時に圧縮機６１への冷媒の流入を防止する逆止弁６６、電子式膨張弁６３をバイパスする配管に設けられた第２開閉弁６７が配置されている。
また、室内空間７１内には，液配管３から流入した湿り蒸気を発熱負荷によって蒸発させる蒸発器２、室内送風機４１が配置されている。
さらに，室外空間７０内の第１の分岐管８とガス配管４との間には，凝縮器１で凝縮した液冷媒の逆流を防止するための逆Ｕ字型配管２０が設けられると共に，室内空間７１内の第２の分岐管６と液配管３との間には，蒸発器２で蒸発したガス冷媒の逆流を防止するためのＵ字型配管２１が設けられている。
【００４１】
本実施の形態６における凝縮器１を図１１に示しており、その凝縮器１は，プレートフィン３０と流入管１２，流出管９等のチューブ（伝熱管）から構成されるプレートフィンチューブ型熱交換器であり，複数の流入管１２が第１の分岐管８に，複数の流出管９が第１の合流管５に接続され，流入管１２と流出管９を両端とする複数の冷媒流路は水平に配置され，第１の分岐管８と第１の合流管５は重力方向に対して傾斜して配置されている。
第１の分岐管８の上方には，冷媒流れ方向に下り勾配部１３を備えた逆Ｕ字型配管２０が接続され，管端部３１でガス配管４に接続されている。
また，第１の合流管５には，冷媒流れ方向に下り勾配１５を備えたＬ字型配管が接続され，管端部３２で液配管３に接続されている。
【００４２】
本実施の形態６による冷却装置では、圧縮機６１による強制循環運転を行う場合、第２開閉弁６７を閉、開閉弁６５を開とし、電子式膨張弁６７の開度を凝縮器１から流出した冷媒液が減圧されて二相状態の湿り蒸気となる適切な開度に設定し、圧縮機６１を運転する。
そうすると，第１開閉弁である逆止弁６４は圧縮機６１の吐出圧力と吸入圧力との圧力差で閉止されて圧縮機６１による強制循環サイクルが形成される。
また、自然循環運転を行う場合、開閉弁６５を閉、第２開閉弁６７を開とし、電子式膨張弁６３を全開すると、逆止弁６４は冷媒の流れにより開放され、自然循環サイクルが形成される。
【００４３】
本実施の形態６による冷却装置では，圧縮機を用いる蒸気圧縮式の冷凍サイクル装置と自然循環サイクルを切り換え可能な冷却装置において，第１の分岐管８とガス配管４との間に液冷媒の逆流を防止するための逆Ｕ字型配管２０を設けると共に，第２の分岐管６と液配管３との間にガス冷媒の逆流を防止するためのＵ字型配管２１を設けたため，確実に冷媒の逆循環を防止することができる。
また，自然循環運転だけでは冷却能力が不足する発熱負荷に対しても蒸気圧縮式冷凍サイクル装置によって対応可能な冷却装置を提供することができる。
【００４４】
以上，この発明の冷媒自然循環を用いる冷却装置の実施の形態について詳述したが，この発明は，上記の実施の形態に限定されるものではなく，種々の変形が可能である。
例えば，逆Ｕ字型配管は，一端が凝縮器入口部の分岐管に，他端がガス配管に接続される構成を示したが，凝縮器入口部の分岐管近傍であればガス配管の途中に設ける構成としてもよい。
また，Ｕ字型配管についても，一端が蒸発器入口部の分岐管に，他端が液配管に接続される構成を示したが，蒸発器入口部の分岐管近傍であれば液配管の途中に設ける構成としてもよい。
【００４５】
【発明の効果】
以上説明したとおり，少なくとも凝縮器，液配管，蒸発器及びガス配管を順次接続して冷媒回路を構成し，前記凝縮器を前記蒸発器よりも高所に設置するとともに、前記液配管および前記ガス配管を傾斜させて配置して冷媒自然循環により冷却運転を行う冷却装置において，前記凝縮器が複数の冷媒流路を有するプレートフィンチューブ型熱交換器で構成され，前記複数の冷媒流路の流入管及び流出管がそれぞれ第１の分岐管及び第１の合流管に接続されると共に，前記ガス配管が冷媒流れ方向に下り勾配部を設けて前記第１の分岐管の上方に接続され、前記蒸発器が複数の冷媒流路を有するプレートフィンチューブ型熱交換器で構成され，前記複数の冷媒流路の流入管および流出管がそれぞれ第２の分岐管及び第２の合流管に接続されると共に，前記液配管が冷媒流れ方向に上り勾配部を設けて前記第２の分岐管の下方に接続され、前記第１の合流管の下方から略垂直の下り勾配部を設けて前記傾斜した液配管を接続すると共に，第２の合流管の上方から略垂直の上り勾配部を設けて前記傾斜したガス配管を接続するため，安価で簡素な構成で起動時などに発生する冷媒の逆循環を防止でき，安定した冷却性能が得られる冷却装置を提供することができる。
【図面の簡単な説明】
【図１】この発明の実施の形態１に係る冷却装置の構成を示す模式図である。
【図２】同冷却装置の凝縮器の構成を示す斜視図である。
【図３】同冷却装置の逆循環が生じる原理を示す模式図である。
【図４】同冷却装置の凝縮器の他の構成を示す構成図である。
【図５】この発明の実施の形態２に係る冷却装置の構成を示す模式図である。
【図６】この発明の実施の形態３に係る冷却装置の構成を示す模式図である。
【図７】同冷却装置の凝縮器の構成を示す斜視図である。
【図８】この発明の実施の形態４に係る冷却装置の構成を示す模式図である。
【図９】この発明の実施の形態５に係る冷却装置の構成を示す模式図である。
【図１０】この発明の実施の形態６に係る冷却装置の構成を示す模式図である。
【図１１】同冷却装置の凝縮器の構成を示す斜視図である。
【図１２】従来の冷媒自然循環を利用する冷却装置の構成を示す模式図である。
【符号の説明】
１凝縮器，２蒸発器，３液配管，４ガス配管，５第１の合流管，６第２の分岐管，７第２の合流管，８第１の分岐管，９，１１流出管，１０，１２流入管，１３上り勾配部，２０逆Ｕ字型配管，４０室外送風機，４１室内送風機。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cooling device that uses a cooling operation by natural refrigerant circulation, and more particularly, to a structure that prevents reverse circulation from occurring due to a liquid refrigerant flowing backward in a gas pipe during startup.
[0002]
[Prior art]
In recent years, the field of removing heat generated by electronic devices such as communication base stations containing relay electronic devices for mobile communication has been rapidly expanding, and these places require cooling operation throughout the year. Yes.
In these applications, when the outside air temperature is low, such as in winter or at night, it is possible to cool it by ventilation, but a device that prevents intrusion of fog, rain, snow and dust is necessary, and the outside air temperature is Since the room temperature also fluctuates due to fluctuations, stable cooling cannot be performed.
Under such conditions, it is possible to use a cooling device that utilizes the natural circulation of the refrigerant that transports heat from the room to the room by using the refrigerant by utilizing the temperature difference between the room temperature and the outside air temperature. The cooling device using natural refrigerant circulation can significantly reduce the annual power consumption as compared with a normal vapor compression cooling device.
[0003]
By the way, as an example of a cooling device using natural refrigerant circulation (hereinafter referred to as natural circulation), one disclosed in JP-A-9-243111 is known.
FIG. 12 is a schematic diagram showing a configuration of a conventional cooling device disclosed in this publication.
The conventional cooling device has two refrigerant circuits. One refrigerant circuit is a natural circulation circuit 104 in which the refrigerant circulates in the order of the cooler 100, the gas pipe 101, the heat exchanger 102, and the liquid pipe 103, and the other refrigerant circuit includes the condensing unit 200, the liquid pipe 201, This is a cooling auxiliary circuit 204 in which the refrigerant circulates in the order of the expansion valve 202, the heat exchanger 102, and the gas pipe 203.
[0004]
Of these, the natural circulation circuit 104 is a circuit that runs vertically in the building, and the interior of the building is cooled by the refrigerant in the circuit. That is, the cooler 100 is disposed indoors, and the fan 105 applies the indoor air to the cooler 100 to perform effective cooling.
The heat exchanger 102 is arranged vertically at the upper end of the natural circulation circuit 104 with the connection port with the gas pipe 101 facing up and the connection port with the liquid pipe 103 facing down. Typically, the heat exchanger 102 is installed at the top of the building along with other components of the auxiliary cooling circuit 204 such as the condensing unit 200.
The cooling auxiliary circuit 204 includes a compressor and a condenser in the condensing unit 200, and is a generally known vapor compression refrigeration cycle. The natural circulation circuit 104 and the cooling auxiliary circuit 204 are different refrigerant circuit systems. However, heat exchange is performed in the heat exchanger 102, and the natural circulation circuit 104 functions as a condenser. On the other hand, it functions as an evaporator (cooler).
[0005]
Next, the operation of the conventional cooling device will be described.
The refrigerant in the natural circulation circuit 104 is evaporated and vaporized in the cooler 100 to become refrigerant gas. The refrigerant gas generated in the cooler 100 is guided from the cooler 100 to the heat exchanger 102 through the gas pipe 101. The refrigerant gas is cooled and condensed / liquefied in the heat exchanger 102 by exchanging heat with the refrigerant liquid (wet steam) in the cooling auxiliary circuit 204.
Since the heat exchanger 102 is arranged vertically, the liquefied refrigerant in the natural circulation circuit 104 flows down in the heat exchanger 102 due to gravity. The condensed liquid refrigerant flows out from the connection port with the lower liquid pipe 103 and is supplied again to the cooler 100 through the liquid pipe 103.
[0006]
As described above, since the heat exchanger 102 is arranged vertically, the flow of the refrigerant liquid in the heat exchanger 102 is always downward, and the refrigerant circulates in such a direction that the refrigerant gas always rises up the gas pipe 101. . If the circulation of the refrigerant is reversed, the refrigerant gas will rise in the liquid pipe 103, and due to the pressure loss of the refrigerant gas, the refrigerant circulation speed will decrease below the expected value, and the cooling capacity will decrease. In the conventional cooling device, since the refrigerant always circulates in the correct direction, the desired high cooling capacity can be stably exhibited.
[0007]
[Problems to be solved by the invention]
A conventional cooling device equipped with a natural circulation circuit has a heat exchanger 102 at the upper end of the natural circulation circuit 104, with the connection port with the gas pipe 101 up and with the connection port with the liquid pipe 103 down, However, when a plate fin type heat exchanger is used in a natural circulation circuit, the heat exchanger generally has a plurality of refrigerant flow paths and branch pipes and junction pipes to which the refrigerant flow paths are connected. However, there is a problem that the connection structure between the gas pipe and the liquid pipe is not considered in terms of preventing the reverse circulation of the refrigerant.
Further, the conventional cooling device has a configuration in which the heat exchanger 102 is arranged vertically, but the point of preventing the reverse circulation of the refrigerant is not considered even when the refrigerant flow path is arranged horizontally. There was a problem.
[0008]
The present invention has been made to solve the above-described conventional problems, and in a cooling device using natural refrigerant circulation, prevents liquid refrigerant from flowing back through a gas pipe and causing reverse circulation at the time of startup or the like. An object of the present invention is to provide a cooling device with a simple and inexpensive structure.
[0009]
[Means for Solving the Problems]
  The cooling device according to claim 1 of the present invention includes at least a condenser, a liquid pipe, an evaporator, and a gas pipe.Sequential connectionTo construct a refrigerant circuit and install the condenser at a higher position than the evaporatorIn addition, the liquid pipe and the gas pipe are inclined and arranged.In a cooling device that performs a cooling operation by natural refrigerant circulation, the condenser is configured by a plate fin tube heat exchanger having a plurality of refrigerant flow paths, and an inflow pipe and an outflow pipe of the plurality of refrigerant flow paths are respectively first. And the gas pipe is connected to the upper side of the first branch pipe by providing a descending gradient portion in the refrigerant flow direction.The evaporator is composed of a plate fin tube heat exchanger having a plurality of refrigerant flow paths, and an inflow pipe and an outflow pipe of the plurality of refrigerant flow paths are connected to a second branch pipe and a second junction pipe, respectively. In addition, the liquid pipe is provided with an ascending slope portion in the refrigerant flow direction and connected to the lower side of the second branch pipe, and is provided with a substantially vertical descending slope portion from the lower side of the first merging pipe to be inclined. Connect the liquid pipe and connect the inclined gas pipe by providing a substantially vertical ascending portion from above the second junction pipe.It is characterized by this.
[0010]
  The cooling device according to claim 2 of the present invention has the above-described configuration,A configuration in which the highest position of the descending slope portion of the gas pipe is set 20 mm or more higher than the highest position of the condenser, and a configuration in which the lowest position of the rising slope portion of the liquid pipe is set 20 mm or more lower than the lowest position of the evaporator. HavingIt is a feature.
[0011]
  The cooling device according to claim 3 of the present invention is:In addition to the above configuration, at least one of the plurality of refrigerant channels in the condenser and the plurality of refrigerant channels in the evaporator is arranged so that the column direction is vertical, and the stage direction is horizontal. Characterized by being placedIs.
[0012]
  According to a fourth aspect of the present invention, there is provided a cooling device in which at least a condenser, a liquid pipe, an evaporator and a gas pipe are sequentially connected to form a refrigerant circuit, and the condenser is installed at a higher position than the evaporator. In the cooling device that performs the cooling operation by natural circulation of the refrigerant, the condenser is configured by a plate fin tube type heat exchanger having a plurality of refrigerant flow paths.In addition, the row direction of the plurality of refrigerant channels is arranged vertically, and the step direction is arranged horizontally.The inflow pipes and the outflow pipes of the plurality of refrigerant flow paths are connected to the first branch pipe and the first junction pipe, respectively, and the inflow pipe descends in the refrigerant flow direction from below the first branch pipe. A gradient portion is provided and connected to the inlet portion of the condenser, and the outflow pipe is provided from the outlet portion of the condenser with a downward gradient portion in the refrigerant flow direction and connected to the upper side of the first junction pipe, 1 branch pipe is placed higher than the highest position of the condenser, and the first junction pipe is placed lower than the lowest position of the condenser,The evaporator is composed of a plate fin tube type heat exchanger having a plurality of refrigerant channels, the column direction of the plurality of refrigerant channels is arranged vertically, the stage direction is arranged horizontally, The inflow pipe and the outflow pipe of the refrigerant flow path are connected to the second branch pipe and the second junction pipe, respectively, and the inflow pipe is provided with an ascending slope portion in the refrigerant flow direction from above the second branch pipe. Connected to the inlet of the evaporator,
The outflow pipe is provided with an ascending slope in the refrigerant flow direction from the outlet of the evaporator and is connected to the lower side of the second junction pipe, and the second branch pipe is located at a position lower than the lowest position of the evaporator. In addition, the second junction pipe is installed at a higher position than the highest position of the evaporator.It is characterized by.
[0013]
  The cooling device according to claim 5 of the present invention is:An evaporator of a vapor compression refrigeration cycle apparatus is disposed in the vicinity of the evaporator.Is.
[0014]
  The cooling device according to claim 6 of the present invention is:A first on-off valve is provided in the gas pipe connecting the evaporator outlet and the condenser inlet, a compressor is connected to the condenser side of the gas pipe from the first on-off valve, and the condenser outlet An expansion valve is provided in the liquid pipe connecting the evaporator inlet, a second on-off valve is provided in the pipe bypassing the expansion valve, and a refrigeration cycle is performed in the path of the compressor, condenser, expansion valve, and evaporator. And is configured to be able to switch between forced circulation operation by compressor operation and natural circulation operation by compressor stop by opening and closing the first on-off valve and the second on-off valve.Is.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1(Reference example).
  1 is a schematic diagram showing the configuration of a cooling device according to Embodiment 1 of the present invention, FIG. 2 is a perspective view showing the configuration of a condenser of the cooling device, and FIG. 3 shows the principle of reverse circulation of the cooling device. It is a schematic diagram.
  As shown in FIG. 1, it is comprised from the condenser 1 and the evaporator 2, and the liquid piping 3 and the gas piping 4 for connecting them.
  A plurality of inflow pipes 12 and outflow pipes 9 are connected to the condenser 1, the other end of the inflow pipe 12 is connected to the first branch pipe 8, and the other end of the outflow pipe 9 is connected to the first junction pipe 5. It is connected. Similarly, a plurality of inflow pipes 10 and outflow pipes 11 are connected to the evaporator 2, the other end of the inflow pipe 10 is connected to the second branch pipe 6, and the other end of the outflow pipe 11 is connected to the second junction. Connected to tube 7.
[0019]
Further, the first junction pipe 5 and the second branch pipe 6 are connected by the liquid pipe 3, and the first branch pipe 8 and the second junction pipe 7 are connected to the upper side of the first branch pipe 8. The gas pipe 4 is connected via an inverted U-shaped pipe 20 provided with a downward gradient portion 13 in the flow direction. Here, ascending and descending slopes are defined as the gradient with respect to the refrigerant flow direction (refrigerant circulates in the order of condenser 1, liquid pipe 3, evaporator 2 and gas pipe 4) when the refrigerant naturally circulates in the positive direction. Shall mean.
The highest position of the inverted U-shaped pipe 20 is set 20 mm or more higher than the highest position of the condenser 1.
The condenser 1 is provided with an outdoor fan 40, and the evaporator 2 is provided with an indoor fan 41. Outdoor air is forced to the outer surface of the condenser 1, and indoor air is forced to the outer surface of the evaporator 2. Supplied. The condenser 1 is installed at a higher position than the evaporator 2, and the upper surface of the condenser 1 and the lower surface of the evaporator 2 are installed with a height difference of about several tens of centimeters, for example.
[0020]
In FIG. 2, the condenser 1 is a plate fin tube type heat exchanger composed of a plate fin 30 and tubes (heat transfer tubes) such as an inflow pipe 12 and an outflow pipe 9, and the column direction is vertical and the step direction is Placed horizontally.
A plurality of inflow pipes 12 are connected to the first branch pipe 8, a plurality of outflow pipes 9 are connected to the first junction pipe 5, and a plurality of refrigerant flow paths having the inflow pipe 12 and the outflow pipe 9 at both ends are horizontal. The first branch pipe 8 and the first junction pipe 5 are also arranged horizontally. Above the first branch pipe 8, an inverted U-shaped pipe 20 having a downward slope portion 13 in the refrigerant flow direction is connected, and a pipe end 31 is connected to the gas pipe 4.
Further, a straight pipe having a downward gradient in the refrigerant flow direction is connected to the first junction pipe 5, and is connected to the liquid pipe 3 at the pipe end portion 32.
The heat transfer tubes such as the inflow tube 12 and the outflow tube 9 are about 6 mm to 13 mm, for example, and the branch tube 8, the merge tube 5, the liquid pipe 3, and the gas pipe 4 are about 9 mm to 20 mm, for example. .
[0021]
The operation of the cooling apparatus configured as described above according to Embodiment 1 of the present invention will be described with reference to FIG.
This cooling device is used, for example, in places where cooling is required throughout the year. When the room temperature is higher than the outside air temperature, a cooling operation by natural refrigerant circulation is performed using the temperature difference between the room and the outside air.
In the natural circulation operation, the liquid refrigerant condensed in the condenser 1 flows out from the plurality of outflow pipes 9, joins the first joining pipe 5, and descends the liquid pipe 3. The liquid refrigerant descending the liquid pipe 3 is branched into a plurality of inflow pipes 10 by the second branch pipe 6 and flows into the evaporator 2.
The gas refrigerant evaporated in the evaporator 2 flows out from the outflow pipe 11, joins the second joining pipe 7, and ascends the gas pipe 4. The refrigerant that has risen in the gas pipe 4 passes through the inverted U-shaped pipe 20, descends the descending slope portion 13, is branched into a plurality of inflow pipes 12 by the first branch pipe 8, and returns to the condenser 1. A circulation cycle is formed.
[0022]
Here, when the outdoor blower 40 is stopped at the time of start-up or to prevent a decrease in indoor temperature, the refrigerant may circulate in reverse. This principle will be described with reference to FIG.
In FIG. 3, (a) is a state in which the indoor blower 41 is operated and the outdoor blower 40 is stopped, (b) is a state in which the outdoor blower 41 is started from the state (a), and (c) is (b). The state where the reverse circulation has occurred from the state of is shown. Moreover, the black coating in the condenser 1 and the evaporator 2 indicates the refrigerant liquid.
As shown in FIG. 3A, when the outdoor blower 40 is stopped, the amount of condensation in the condenser 1 is very small, and the refrigerant mainly exists in the evaporator 2. When the outdoor blower 40 is started in this state, as shown in (b), the heat exchange performance in the condenser 1 increases and the pressure decreases, so that the refrigerant flows from the evaporator 2 to the condenser 1 and the liquid pipe 3 and gas. It moves through the pipe 4.
[0023]
At the stage when the movement of the refrigerant is almost completed (stage where the pressure in the refrigerant circuit is almost equalized), the liquid pipe 3 becomes only the gas refrigerant and the liquid refrigerant is left in the gas pipe 4 as shown in (c). Then, the remaining liquid refrigerant flows backward from the gas pipe 4 to the evaporator 2. The liquid refrigerant that has flowed back to the evaporator 2 evaporates in the evaporator 2 to become refrigerant gas, so that the pressure rises and prevents the liquid refrigerant from flowing down (circulating in the forward direction) from the condenser 1.
This reverse circulation phenomenon occurs continuously when the liquid refrigerant existing in the gas pipe 4 is connected to the liquid refrigerant existing in the evaporator 2 and the condenser 1 to generate a liquid head that always becomes a circulation driving force. become.
Note that this reverse circulation phenomenon depends on the distribution state (uneven distribution) of the refrigerant amount in the evaporator 2 when the outdoor blower 40 is stopped, and this distribution state is caused by the intake air of an indoor unit (not shown) incorporating the evaporator 2. Depends on temperature distribution.
[0024]
In the first embodiment, an inverted U-shaped pipe 20 having a downward gradient portion 13 in the refrigerant flow direction is connected above the first branch pipe 8, and the liquid refrigerant is left behind in the gas pipe 4. Even in such a state, the liquid refrigerant is interrupted by the inverted U-shaped pipe 20, and the liquid head which is the feeding and circulation driving force can be cut to prevent continuous reverse circulation.
In addition, since the highest position of the inverted U-shaped pipe 20 is higher than the highest position of the condenser 1 by 20 mm or more, the inverted U-character is formed even when the heat transfer tube at the highest position of the condenser 1 is filled with the saturated liquid. It is possible to provide a cooling device that can fill the mold pipe 20 with a gas refrigerant and reliably prevent reverse circulation.
[0025]
Further, in the first embodiment, the configuration in which the inverted U-shaped pipe 20 provided with the downward gradient portion 13 in the refrigerant flow direction is connected above the first branch pipe 8 is shown in FIG. Of course, even if the inverted V-shaped pipe 20 having the descending slope portion 13 is used, the same effect can be obtained.
[0026]
Further, in the first embodiment, a plurality of refrigerant flow paths in the condenser 1 and a plurality of refrigerant flow paths in the evaporator are arranged horizontally, and the first and second merge pipes 5 and 7 and the first and second flow paths are arranged. Since the branch pipes 8 and 6 are also arranged horizontally, even if there is a height restriction from the ground on the communication base station where the cooling device is installed, the height difference necessary for natural refrigerant circulation can be secured, Moreover, since the height from the lower surface of the evaporator 2 to the upper surface of the condenser 1 can be kept low, there is an effect that the cooling device can be reduced in size.
[0027]
Embodiment 2(Reference example).
  FIG. 5 is a schematic diagram showing a configuration of a cooling device according to Embodiment 2 of the present invention.
  In the cooling device according to the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
  In the second embodiment, the configuration different from the first embodiment is that a U-shaped pipe 21 having an up-gradient portion 14 is provided between the liquid pipe 3 and the second branch pipe 6 in the refrigerant flow direction, The U-shaped pipe 21 is connected to the lower side of the second branch pipe 6.
  The lowest position of the U-shaped pipe 21 is set 20 mm or more lower than the lowest position of the evaporator 2.
[0028]
In the second embodiment, in addition to the effects of the first embodiment, a U-shaped pipe 21 provided with an up-gradient portion 14 in the refrigerant flow direction is connected below the second branch pipe 6. The inside of the gradient 14 is always filled with liquid refrigerant, the backflow of the gas refrigerant evaporated in the evaporator 2 can be prevented, and the backflow can be prevented by always supplying the gas refrigerant to the outflow pipe 11.
Further, since the lowest position of the U-shaped pipe 21 is 20 mm or more lower than the lowest position of the evaporator 2, even if the heat transfer tube in the lowest position of the evaporator 2 is filled with the gas refrigerant, the reverse flow of the gas refrigerant is prevented. It is possible to provide a cooling device that can suppress and reliably prevent reverse circulation.
[0029]
Embodiment 3 FIG.
FIG. 6 is a schematic diagram showing a configuration of a cooling device according to Embodiment 3 of the present invention, and FIG. 7 is a perspective view showing a configuration of a condenser of the cooling device.
In the cooling device of the third embodiment, the same components as those of the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
In the third embodiment, the configuration different from that of the second embodiment is that a down-gradient portion 15 in the refrigerant flow direction is connected between the first merging pipe 5 and the liquid pipe 3 below the first merging pipe 5. And an ascending gradient portion 16 in the refrigerant flow direction connected above the second junction pipe 7 is also provided between the second junction pipe 7 and the gas pipe 4.
[0030]
Unlike the first embodiment, the condenser 1 shown in FIG. 7 is connected to an L-shaped pipe having a downward gradient portion 15 in the refrigerant flow direction below the first merging pipe 5. Connected to the pipe 3.
[0031]
In the third embodiment, in addition to the effects of the second embodiment, the downward gradient portion 15 is provided in the refrigerant flow direction below the first merging pipe 5, so that the liquid refrigerant merged in the first merging pipe 5 is Therefore, it is possible to reliably flow down to the liquid pipe 3 and to prevent reverse circulation of the liquid refrigerant.
Further, since the upward gradient 16 is provided in the refrigerant flow direction above the second merging pipe 7, the gas refrigerant merged in the second merging pipe 7 can be surely flowed into the gas pipe 4, and the reverse of the gas refrigerant. Circulation can be prevented.
[0032]
Embodiment 4 FIG.
FIG. 8 is a schematic diagram showing a configuration of a cooling device according to Embodiment 4 of the present invention.
In the cooling device of the fourth embodiment, the same components as those of the third embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
The fourth embodiment is different from the third embodiment in that the inverted U-shaped pipe 20 and the liquid pipe 3 and the second branch pipe 6 provided between the gas pipe 4 and the first branch pipe 8 are different. A U-shaped pipe 21 provided between the first and second merging pipes 5 and the liquid pipe 3, and a downward gradient portion 15 in the refrigerant flow direction and the second merging pipe 7 and the gas pipe 4. An inflow pipe 12 having a downflow gradient portion 22 in the refrigerant flow direction is connected below the first branch pipe 8 connected to the gas pipe 4 instead of the upflow gradient portion 16 provided between An outflow pipe 9 having a downward gradient portion 23 in the refrigerant flow direction is connected to the upper side of the first merging pipe 5, and an upward flow in the refrigerant flow direction is above the second branch pipe 6 connected to the liquid pipe 3. An inflow pipe 10 having a gradient portion 24 is connected, and an upward gradient portion 25 in the refrigerant flow direction is provided below the second junction pipe 7. Outflow pipe 11 is a point connected was e.
Further, by providing the descending slopes 22 and 23 and the ascending slopes 24 and 25, the first branch pipe 8 is higher than the highest position of the condenser 1, and the first junction pipe 5 is provided in the condenser 1. The second branch pipe 6 is installed at a lower position than the lowest position of the evaporator 2, and the second junction pipe 7 is installed at a higher position than the highest position of the evaporator 2.
[0033]
In the fourth embodiment, the downward gradient portion 22 in the refrigerant flow direction is provided below the first branch pipe 8 so that the first branch pipe 8 is higher than the highest position of the condenser 1. As in the first embodiment, the back flow of the liquid refrigerant can be prevented.
In addition, since the downward gradient portion 23 in the refrigerant flow direction is provided above the first merge pipe 5 so that the first merge pipe 5 is lower than the lowest position of the condenser, similarly to the third embodiment. The liquid refrigerant condensed by the condenser 1 can be reliably supplied to the first junction pipe 5, and the reverse circulation of the liquid refrigerant can be prevented.
Further, since the upward gradient portion 24 in the refrigerant flow direction is provided above the second branch pipe 6 so that the second branch pipe 6 is lower than the lowest position of the evaporator 2, the same as in the second embodiment. Further, the back flow of the gas refrigerant evaporated in the evaporator 2 can be prevented.
Further, since the ascending gradient portion 25 in the refrigerant flow direction is provided below the second merging pipe 7 so that the second merging pipe 7 is higher than the highest position of the evaporator 2, the same as in the third embodiment. Thus, the gas refrigerant evaporated in the evaporator 2 can surely flow into the second junction pipe 7 to prevent reverse circulation of the gas refrigerant.
[0034]
The first branch pipe 8 is 20 mm or more higher than the highest position of the condenser 1, the first junction pipe 5 is 20 mm or higher lower than the lowest position of the condenser 1, and the second branch pipe 6 Is installed at a position 20 mm or more lower than the lowest position of the evaporator 2, and the second junction pipe 7 is installed at a height 20 mm or more higher than the highest position of the evaporator 2, as in the first and second embodiments. Needless to say, the effects of
[0035]
Embodiment 5 FIG.
FIG. 9 is a block diagram showing a cooling device installed in the communication base station 50 according to Embodiment 5 of the present invention.
This shows an example in which a cooling device using natural refrigerant circulation is used in combination with a vapor compression refrigeration cycle device using a compressor.
As shown in FIG. 9, the outdoor unit 53 is fixed to the upper part of the outer wall of the communication base station 50 by an outdoor unit support base 52, and the indoor unit 54 and the outdoor unit 53 are connected by the gas pipe 4 and the liquid pipe 3. In addition, the communication base station 50 accommodates the communication device 58 and the indoor unit 54 that are heating elements, and the heat generated from the communication device 58 is cooled by the indoor unit 54.
In FIG. 9, 51a is an outdoor unit inlet, 51b is an outdoor unit outlet, 55a is an indoor unit inlet, and 55b is an indoor unit outlet.
[0036]
Two evaporators 2 and 57 corresponding to the natural circulation cycle and the vapor compression cycle are accommodated in the indoor unit 54, and the heat generation load of the communication device 58 is cooled. Further, the indoor fan 41 for forcing the indoor air to the outer surfaces of the evaporator 2 and the evaporator 57, the partition plate 56a for partitioning the suction side space and the blowout side space of the evaporator 2 and the evaporator 57, and 56b.
The outdoor unit 53 is composed of the condenser 1 and the outdoor blower 40, and the reverse unit is provided between the first branch pipe 8 and the gas pipe 4 to prevent backflow of the liquid refrigerant condensed in the condenser 1. A U-shaped pipe 20 is provided, and a U-shaped pipe 21 is provided between the second branch pipe 6 and the liquid pipe 3 to prevent the backflow of the gas refrigerant evaporated in the evaporator 2. Yes.
An outdoor unit 59 of a vapor compression refrigeration cycle using a compressor is installed beside the communication base station 50 and connected to the evaporator 57 by a pipe.
Note that the condenser 1 of the outdoor unit 53 is arranged at a higher position than the evaporator 2 of the indoor unit 54, and is arranged with a height difference of about 50 cm here, for example.
[0037]
Next, the operation of the cooling device in the fifth embodiment will be described.
When the indoor temperature is higher than the outside air temperature, the cooling device performs a cooling operation by natural refrigerant circulation using a temperature difference between the room and the outside air.
In the natural circulation operation, the liquid refrigerant condensed in the condenser 1 descends the liquid pipe 3 and flows into the evaporator 2 through the U-shaped pipe 21. The gas refrigerant evaporated in the evaporator 2 rises in the gas pipe 4 and returns to the condenser 1 through the inverted U-shaped pipe 20 to form a natural circulation cycle.
[0038]
In the fifth embodiment, in a cooling device that is used in combination with a vapor compression refrigeration cycle device that uses a compressor, a reverse flow for preventing the backflow of the liquid refrigerant between the first branch pipe 8 and the gas pipe 4. Since the U-shaped pipe 20 is provided and the U-shaped pipe 21 for preventing the backflow of the gas refrigerant is provided between the second branch pipe 6 and the liquid pipe 3, the reverse circulation of the refrigerant is surely prevented. be able to.
Further, since the vapor compression refrigeration cycle apparatus is provided, it is possible to provide a cooling apparatus that can cope with a heat generation load whose cooling capacity is insufficient only by natural circulation operation by the vapor compression refrigeration cycle apparatus.
[0039]
Embodiment 6 FIG.
FIG. 10 is a schematic view showing a configuration of a cooling device according to Embodiment 6 of the present invention, and FIG. 11 is a perspective view showing a condenser of the cooling device.
This cooling device is installed on a door or wall of a communication base station, computer room, etc., and shares a condenser 1, an evaporator 2, a liquid pipe 3, and a gas pipe 4, and uses a vapor compression refrigeration cycle by a compressor. This is a cooling device that switches between the device and the natural circulation cycle to cool the heat generated by communication equipment.
In FIG. 10, 60 is a casing of the cooling device, 61 is a compressor connected to the gas pipe 4 via a check valve 66, 62 is an accumulator connected to the gas pipe 4 via an on-off valve 65, and 63 is As an expansion device provided in the liquid pipe 3, for example, an electronic expansion valve, 64 is a check valve which is a first on-off valve provided in the gas pipe 4, and 67 is connected to the liquid pipe 3 and is an electronic expansion valve. The second on-off valve is provided in the pipe bypassing 63, and the same reference numerals are given to the same components as those in the fifth embodiment, and detailed description thereof is omitted.
[0040]
In the cooling device according to the sixth embodiment, the interior of the housing 60 is separated into an outdoor space 70 and an indoor space 71 by a partition plate 68.
In the outdoor space 70, the compressor 61 for compressing the refrigerant gas, the condenser 1 for cooling and liquefying the refrigerant gas, the outdoor blower 40, and the high-temperature and high-pressure refrigerant liquid exiting the condenser 1 are decompressed. An electronic expansion valve 63 for generating two-phase wet steam, an accumulator 62 for preventing liquid return to the compressor 61 in the case of a transient phenomenon or refrigerant overfilling, the compressor 61 and the accumulator 62 On-off valve 65 for bypassing, check valve 64 as a first on-off valve provided in the gas pipe 4, check valve 66 for preventing refrigerant from flowing into the compressor 61 during natural circulation operation, electronic expansion A second on-off valve 67 provided in a pipe that bypasses the valve 63 is disposed.
In the indoor space 71, an evaporator 2 and an indoor blower 41 that evaporate the wet steam flowing in from the liquid pipe 3 by a heat generation load are disposed.
Further, an inverted U-shaped pipe 20 is provided between the first branch pipe 8 and the gas pipe 4 in the outdoor space 70 to prevent the backflow of the liquid refrigerant condensed by the condenser 1. Between the second branch pipe 6 and the liquid pipe 3 in the space 71, a U-shaped pipe 21 for preventing the backflow of the gas refrigerant evaporated by the evaporator 2 is provided.
[0041]
The condenser 1 in the sixth embodiment is shown in FIG. 11, and the condenser 1 is a plate fin tube type heat composed of a plate fin 30 and tubes (heat transfer tubes) such as the inflow pipe 12 and the outflow pipe 9. A plurality of inflow pipes 12 connected to the first branch pipe 8, a plurality of outflow pipes 9 connected to the first junction pipe 5, and a plurality of refrigerant flows having the inflow pipe 12 and the outflow pipe 9 at both ends. The path is horizontally arranged, and the first branch pipe 8 and the first junction pipe 5 are arranged to be inclined with respect to the direction of gravity.
Above the first branch pipe 8, an inverted U-shaped pipe 20 having a downward slope portion 13 in the refrigerant flow direction is connected, and a pipe end 31 is connected to the gas pipe 4.
Further, an L-shaped pipe having a downward gradient 15 in the refrigerant flow direction is connected to the first merging pipe 5, and is connected to the liquid pipe 3 at the pipe end 32.
[0042]
In the cooling device according to the sixth embodiment, when the forced circulation operation by the compressor 61 is performed, the second on-off valve 67 is closed, the on-off valve 65 is opened, and the opening degree of the electronic expansion valve 67 flows out of the condenser 1. The compressor 61 is operated by setting the opening degree so that the refrigerant liquid is decompressed and becomes a two-phase wet steam.
Then, the check valve 64, which is the first on-off valve, is closed by the pressure difference between the discharge pressure and the suction pressure of the compressor 61, and a forced circulation cycle by the compressor 61 is formed.
Further, when performing natural circulation operation, when the on-off valve 65 is closed, the second on-off valve 67 is opened, and the electronic expansion valve 63 is fully opened, the check valve 64 is opened by the flow of the refrigerant to form a natural circulation cycle. Is done.
[0043]
In the cooling apparatus according to the sixth embodiment, the liquid refrigerant is interposed between the first branch pipe 8 and the gas pipe 4 in a vapor compression refrigeration cycle apparatus using a compressor and a cooling apparatus capable of switching between natural circulation cycles. Since the reverse U-shaped pipe 20 for preventing the backflow is provided and the U-shaped pipe 21 for preventing the backflow of the gas refrigerant is provided between the second branch pipe 6 and the liquid pipe 3, it is ensured. The reverse circulation of the refrigerant can be prevented.
In addition, it is possible to provide a cooling device that can cope with a heat generation load whose cooling capacity is insufficient only by natural circulation operation by the vapor compression refrigeration cycle device.
[0044]
As mentioned above, although the embodiment of the cooling device using the natural refrigerant circulation of the present invention has been described in detail, the present invention is not limited to the above embodiment, and various modifications are possible.
For example, an inverted U-shaped pipe has a configuration in which one end is connected to the branch pipe at the condenser inlet and the other end is connected to the gas pipe. It is good also as a structure provided in.
In addition, the U-shaped pipe has a configuration in which one end is connected to the branch pipe at the evaporator inlet and the other end is connected to the liquid pipe. It is good also as a structure provided in.
[0045]
【The invention's effect】
  As explained above, at least the condenser, liquid piping, evaporator and gas pipingSequential connectionTo construct a refrigerant circuit and install the condenser at a higher position than the evaporatorIn addition, the liquid pipe and the gas pipe are inclined and arranged.In a cooling device that performs a cooling operation by natural refrigerant circulation, the condenser is configured by a plate fin tube heat exchanger having a plurality of refrigerant flow paths, and an inflow pipe and an outflow pipe of the plurality of refrigerant flow paths are respectively first. And the gas pipe is connected to the upper side of the first branch pipe by providing a descending gradient portion in the refrigerant flow direction.The evaporator is composed of a plate fin tube heat exchanger having a plurality of refrigerant flow paths, and an inflow pipe and an outflow pipe of the plurality of refrigerant flow paths are connected to a second branch pipe and a second junction pipe, respectively. In addition, the liquid pipe is provided with an ascending slope portion in the refrigerant flow direction and connected to the lower side of the second branch pipe, and is provided with a substantially vertical descending slope portion from the lower side of the first merging pipe to be inclined. Connect the liquid pipe and connect the inclined gas pipe by providing a substantially vertical ascending portion from above the second junction pipe.Therefore, it is possible to provide a cooling device that can prevent the reverse circulation of the refrigerant generated at the time of start-up or the like with an inexpensive and simple configuration and obtain a stable cooling performance.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a configuration of a cooling device according to Embodiment 1 of the present invention.
FIG. 2 is a perspective view showing a configuration of a condenser of the cooling device.
FIG. 3 is a schematic diagram showing the principle of reverse circulation of the cooling device.
FIG. 4 is a configuration diagram showing another configuration of the condenser of the cooling device.
FIG. 5 is a schematic diagram showing a configuration of a cooling device according to Embodiment 2 of the present invention.
FIG. 6 is a schematic diagram showing a configuration of a cooling device according to Embodiment 3 of the present invention.
FIG. 7 is a perspective view showing a configuration of a condenser of the cooling device.
FIG. 8 is a schematic diagram showing a configuration of a cooling device according to Embodiment 4 of the present invention.
FIG. 9 is a schematic diagram showing a configuration of a cooling device according to Embodiment 5 of the present invention.
FIG. 10 is a schematic diagram showing a configuration of a cooling device according to Embodiment 6 of the present invention.
FIG. 11 is a perspective view showing a configuration of a condenser of the cooling device.
FIG. 12 is a schematic diagram showing a configuration of a conventional cooling device using natural refrigerant circulation.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Condenser, 2 Evaporator, 3 Liquid piping, 4 Gas piping, 5 1st merge pipe, 6 2nd branch pipe, 7 2nd merge pipe, 8 1st branch pipe, 9, 11 Outflow pipe, 10, 12 Inflow pipe, 13 Ascending slope, 20 Inverted U-shaped pipe, 40 Outdoor fan, 41 Indoor fan.

Claims

At least a condenser, a liquid pipe, an evaporator and a gas pipe are sequentially connected to form a refrigerant circuit, the condenser is installed at a higher position than the evaporator, and the liquid pipe and the gas pipe are inclined. In a cooling device that is arranged and performs cooling operation by natural circulation of refrigerant,
The condenser is composed of a plate fin tube heat exchanger having a plurality of refrigerant flow paths, and an inflow pipe and an outflow pipe of the plurality of refrigerant flow paths are connected to a first branch pipe and a first junction pipe, respectively. And the gas pipe is connected to the upper side of the first branch pipe by providing a downward gradient portion in the refrigerant flow direction,
The evaporator is composed of a plate fin tube heat exchanger having a plurality of refrigerant flow paths, and an inflow pipe and an outflow pipe of the plurality of refrigerant flow paths are connected to a second branch pipe and a second junction pipe, respectively. And the liquid pipe is connected to the lower side of the second branch pipe by providing an upward gradient portion in the refrigerant flow direction,
The inclined gas pipe is connected to the inclined liquid pipe by providing a substantially vertical down-gradient portion from the lower side of the first merge pipe, and the inclined gas pipe is provided with a substantially vertical up-gradient section from the upper side of the second merge pipe. A cooling device characterized by connecting .

A configuration in which the highest position of the descending gradient portion connected to the gas pipe is set 20 mm or more higher than the highest position of the condenser, and the lowest position of the ascending gradient portion connected to the liquid pipe is lower than the lowest position of the evaporator. The cooling device according to claim 1, wherein the cooling device is configured to be lower by 20 mm or more.

At least one of the plurality of refrigerant channels in the condenser and the plurality of refrigerant channels in the evaporator is arranged so that the column direction is vertical and the stage direction is horizontal. The cooling device according to claim 1 or 2, characterized by the above.

At least a condenser, a liquid pipe, an evaporator, and a gas pipe are sequentially connected to form a refrigerant circuit, and the condenser is installed at a higher position than the evaporator to perform a cooling operation by natural refrigerant circulation. In
Consists of a plate fin tube heat exchanger in which the condenser has a plurality of refrigerant flow paths Rutotomoni, said plurality of column direction of the coolant flow path is disposed vertically, the column direction are arranged horizontally, the plurality of The inflow pipe and the outflow pipe of the refrigerant flow path are connected to the first branch pipe and the first junction pipe, respectively, and the inflow pipe is provided with a downward gradient portion in the refrigerant flow direction from below the first branch pipe. Connected to the inlet of the condenser, and the outlet pipe is provided above the first junction pipe with a descending slope in the refrigerant flow direction from the outlet of the condenser, and connected to the first branch pipe. At a position higher than the highest position of the condenser and the first junction pipe at a lower position than the lowest position of the condenser,
The evaporator is composed of a plate fin tube type heat exchanger having a plurality of refrigerant channels, the column direction of the plurality of refrigerant channels is arranged vertically, the stage direction is arranged horizontally, The inflow pipe and the outflow pipe of the refrigerant flow path are connected to the second branch pipe and the second junction pipe, respectively, and the inflow pipe is provided with an ascending slope portion in the refrigerant flow direction from above the second branch pipe. Connected to the inlet of the evaporator,
The outflow pipe is provided with an ascending slope in the refrigerant flow direction from the outlet of the evaporator and is connected to the lower side of the second junction pipe, and the second branch pipe is located at a position lower than the lowest position of the evaporator. In addition, the second merging pipe is installed at a higher position than the highest position of the evaporator .

The cooling device according to any one of claims 1 to 4 , wherein an evaporator of a vapor compression refrigeration cycle apparatus is disposed in the vicinity of the evaporator.

A first on-off valve is provided in the gas pipe connecting the evaporator outlet and the condenser inlet, a compressor is connected to the condenser side of the gas pipe from the first on-off valve, and the condenser outlet An expansion valve is provided in the liquid pipe connecting the evaporator inlet, a second on-off valve is provided in the pipe bypassing the expansion valve, and a refrigeration cycle is performed in the path of the compressor, condenser, expansion valve, and evaporator. 2. The system according to claim 1, wherein the first on-off valve and the second on-off valve are opened and closed to switch between forced circulation operation by compressor operation and natural circulation operation by compressor stop. The cooling device according to any one of 5 .