JP4031849B2 - Refrigeration air conditioner - Google Patents

Refrigeration air conditioner Download PDF

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Publication number
JP4031849B2
JP4031849B2 JP25694697A JP25694697A JP4031849B2 JP 4031849 B2 JP4031849 B2 JP 4031849B2 JP 25694697 A JP25694697 A JP 25694697A JP 25694697 A JP25694697 A JP 25694697A JP 4031849 B2 JP4031849 B2 JP 4031849B2
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compressor
expansion mechanism
refrigerant
radiator
refrigerating
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JPH1194379A (en
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正美 根岸
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Sanden Holdings Corp
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Sanden Corp
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
    • F25B9/002—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant
    • F25B9/008—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant the refrigerant being carbon dioxide
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B1/00—Compression machines, plants or systems with non-reversible cycle
    • F25B1/10—Compression machines, plants or systems with non-reversible cycle with multi-stage compression
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
    • F25B9/06—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point using expanders
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2309/00—Gas cycle refrigeration machines
    • F25B2309/06—Compression machines, plants or systems characterised by the refrigerant being carbon dioxide
    • F25B2309/061—Compression machines, plants or systems characterised by the refrigerant being carbon dioxide with cycle highest pressure above the supercritical pressure

Description

【０００１】
【発明の属する技術分野】
本発明は、二酸化炭素を冷媒として使用する冷凍空調装置に関するものである。
【０００２】
【従来の技術】
従来、この種の二酸化炭素（ＣＯ2）を冷媒として使用する冷凍空調装置として図４に示す冷凍空調装置が一般的に知られている。
【０００３】
この冷凍空調装置は圧縮機１、放熱器２、膨張弁３及び蒸発器４を有し、二酸化炭素冷媒を圧縮機１→放熱器２→膨張弁３→蒸発器４→圧縮機１と矢印に示すよう順次循環させることにより、室内の冷房等の空調を行っている。
【０００４】
【発明が解決しようとする課題】
ところで、ＣＯ2冷媒を使用する冷凍空調装置で、大気に熱放出を行う方式のものにあっては、外気温度が高いときでも所定の冷凍能力を確保するために、高い吐出圧力が得られる圧縮機が必要となる。
【０００５】
即ち、図５のＣＯ2モリエル線図で説明すれば、通常運転では、圧縮機１でＣＯ2冷媒を圧縮して飽和液線及び飽和蒸気線の臨界点を越えた１００kg/cm2まで圧縮する（図５のＡ→Ｂ）。次いで、この圧縮されたＣＯ2冷媒を放熱器２で大気に放熱し（図５のＢ→Ｃ）、更にこの放熱されたＣＯ2冷媒を膨張弁３で等エンタルピ線に沿って膨張させ圧力降下させる（図５のＣ→Ｄ）。この圧力降下により湿り蒸気となったＣＯ2冷媒を蒸発器４で気化し、室内を冷却する（図５のＤ→Ａ）。
【０００６】
一方、外気温度が高く３５℃となったときでも十分な冷却能力を得るためには、図５のＡ→Ｂ’→Ｃ’→Ｄ’とＣＯ2冷媒を循環しなければならず、ここでは１５０kg/cm2程度の吐出圧力が必要となる。
【０００７】
従って、外気温度が高いときでも十分に室内を冷房等できるようにするには、圧縮機１として冷凍能力の大きいものを設置する必要があり、圧縮機１の駆動動力の割には効率の悪いものとなっていた。
【０００８】
本発明の目的は前記従来の課題に鑑み、圧縮機全体の動力を大きくすることなく、かつ、冷凍効果が向上する冷凍空調装置を提供することにある。
【０００９】
【課題を解決するための手段】
本発明は前記課題を解決するため、請求項１の発明は、二酸化炭素の冷媒を圧縮機、放熱器、膨張機構及び蒸発器に順次循環し、超臨界状態で放熱器から熱を放出する蒸気圧縮式の冷凍空調装置において、放熱器を順次直列に接続された第１放熱器と第２放熱器とから構成するとともに、該各放熱器の間に他の圧縮機を挿入し、該他の圧縮機の駆動軸と前記膨張機構の出力軸を連係し、前記他の圧縮機のガス吸入口とガス吐出口を接続し該他方の圧縮機を迂回するバイパス管を設けた構造となっている。
【００１０】
この発明によれば、ＣＯ2冷媒は一方の圧縮機→第１放熱器→他方の圧縮機→第２放熱器→膨張機構→蒸発器→一方の圧縮機と順次循環し、室内冷房等を行う。
【００１１】
この冷凍サイクルで、一方の圧縮機では例えば１００kg/cm2程度まで圧縮し、また、他の圧縮機ではこの冷媒を１５０kg/cm2程度まで圧縮し、所要の吐出圧力を得る。ここで、他方の圧縮機の動力（他方の圧縮機で吐出圧力を１００kg/cm2から１５０kg/cm2まで上昇させるために費やされる動力）と一方の圧縮機の動力（一方の圧縮機で１００kg/cm2から１５０kg/cm2まで上昇させるために費やされる動力）とを比較すると、他方の圧縮機に吸入される冷媒が第１放熱器で一部放熱され、エンタルピが小さくなった分（他方の圧縮機における等エントロピ線の傾きが大きくなった分）、その動力が小さくなる。
【００１２】
また、圧縮機の駆動軸と膨張機構の出力軸が連係しているため、膨張機構での冷媒膨張作用に伴う動力が、他方の圧縮機の冷媒圧縮作用に利用される。さらに、冷凍空調装置の運転始動時で一方の圧縮機がガス圧縮を開始すると、蒸発器及び膨張機構出口部の圧力が降下するとともに、一方の圧縮機で昇圧される圧力は、逆止弁、バイパス管を介して第２放熱器及び膨張機構入口に伝達される。これにより、膨張機構の出口と入口との圧力差が所定圧力差となり、膨張機構が駆動するとともに、この膨張機構の駆動力が他方の圧縮機の駆動力として利用され、他方の圧縮機が駆動する。この他方の圧縮機が駆動した後は、他方の圧縮機の吸入力により全てのＣＯ 2 冷媒が他方の圧縮機に流れ込み、室内冷房等を行う。
【００１３】
請求項２の発明は、請求項１の冷凍空調装置において、バイパス管にガス吐出口からガス吸入口への冷媒流通を規制する逆止弁を設けた構造となっている。
【００１４】
この発明によれば、バイパス管に逆止弁を設けることにより、他の圧縮機から吐出した冷媒がバイパス管を通じて戻ることを防止している。
【００１５】
請求項３の発明は、請求項１又は請求項２の冷凍空調装置において、他方の圧縮機と膨張機構をスクロール式圧縮・膨張機構で構成している。この発明によれば、膨張機構では等エントロピ線に沿って断熱膨張するため、蒸発器への吸入直前のエンタルピが小さくなり、冷凍効果が向上する。
【００１６】
なお、この他方の圧縮機と膨張機構とを一体に形成し両者をユニット化するようにしても良い。
【００１７】
【発明の実施の形態】
図１乃至図３は本発明に係る冷凍空調装置の一実施形態を示すもので、図１は冷凍空調装置の冷媒回路図、図２は第２圧縮機と膨張機構との連係構造を示す概略図、図３は冷凍空調装置のＣＯ2モリエル線図である。なお、図４及び図５で既に説明した従来例と同一構成部分は同一符号をもって表す。
【００１８】
この冷凍空調装置はＣＯ2を冷媒として使用するもので、図１に示すように、一方の圧縮機（以下、第１圧縮機という）１ａ、第１放熱器２ａ、他方の圧縮機（以下、第２圧縮機という）１ｂ、第２放熱器２ｂ、膨張機構３ａ及び蒸発器４を順次冷媒管５で接続し、ＣＯ2冷媒を第１圧縮機１→第１放熱器２ａ→第２圧縮機１ｂ→第２放熱器２ｂ→膨張機構３ａ→蒸発器４→第１圧縮機１ａと順次循環し、蒸発器４の吸熱作用により室内冷房を行っている。また、第２圧縮機１ｂのガス吸入口側の冷媒管５とガス吐出口側の冷媒管５はバイパス管６で接続され、このバイパス管６により第２圧縮機１ｂを迂回するようになっている。また、このバイパス管６には逆止弁７が設置されており、この逆止弁７により第２圧縮機１ｂから吐出したＣＯ2冷媒がこのバイパス管６を通じて戻ることがないよう規制している。
【００１９】
このように構成された冷凍空調装置において、第２圧縮機１ｂ及び膨張機構３ａは図２に示すように構成されている。即ち、第２圧縮機１ｂ及び膨張機構３ａは共にスクロール式の圧縮・膨張機構を採用している。まず、第２圧縮機１ｂはガス吸入口１１を外側にガス吐出口１２を中央にそれぞれ有するもので、旋回スクロール１３を図２の矢印方向（図２に向かって右回り）に回転してガス吸入口１１から流入したＣＯ2冷媒を固定スクロール１４との間で圧縮し、ガス吐出口１２から吐出する構成となっている。
【００２０】
一方、膨張機構３ａは前記第２圧縮機１ｂとは逆の構成、即ちガス吐出口３１を外側にガス吸入口３２を内側にそれぞれ有し、旋回スクロール３３を図２の矢印方向（図２に向かって左回り）に回転してガス吸入口３２から流入したＣＯ2冷媒を固定スクロール３４との間で膨張させ、ガス吐出口３１から吐出する構成となっている。
【００２１】
更に、第２圧縮機１ｂの駆動軸と膨張機構３ａの出力軸は図２に示すようにシャフト８で連結しており、膨張機構３ａの駆動により第２圧縮機１ｂが駆動するとともに、第２圧縮機１ｂと膨張機構３ａをユニット化し一体に形成している。
【００２２】
次に本実施形態に係る冷凍空調装置の駆動状態を説明する。まず、第１圧縮機１ａを稼働するときＣＯ2冷媒が圧縮され、更に第１放熱器２ａに流入して屋外に放熱される。この放熱されたＣＯ2冷媒は第２圧縮機１ｂが未だ駆動していないため、バイパス管６に流れ第２放熱器２ｂに流入する。この第２放熱器２ｂに流れたＣＯ2冷媒は再度放熱され、膨張機構３ａ側に流れる。ここで、膨張機構３ａのガス吸入口３２のガス圧は上昇する一方、膨張機構３ａのガス吐出口３１及び蒸発器４側の圧力が降下するため、膨張機構３ａのガス吸入口３２とガス吐出口３１との圧力差が所定の圧力差となる。これにより、膨張機構３ａのガス吸入口３２からＣＯ2冷媒が流入し、ＣＯ2冷媒の膨張力により旋回スクロール３３が回転するとともに、ＣＯ2冷媒が断熱膨張しながらガス吐出口３１から吐出される。
【００２３】
このような膨張機構３ａの旋回スクロール３３の回転により、この膨張機構３ａに連結する第２圧縮機１ｂが駆動する。ここで、冷凍空調装置の稼働初期時ではバイパス管６にＣＯ2冷媒が流れたが、この第２圧縮機１ｂの駆動により全てのＣＯ2冷媒が第２圧縮機１ｂに吸い込まれる。この第２圧縮機１ｂに吸入されたＣＯ2冷媒はこの第２圧縮機１ｂにより再度断熱圧縮され、この圧縮されたＣＯ2冷媒が第２放熱器２ｂで放熱され、更に膨張機構３ａで断熱膨張される。このように断熱膨張されたＣＯ2冷媒は蒸発器４で室内空気と熱交換し、室内冷房を行う。
【００２４】
以上のような冷凍空調装置の冷却サイクルを図３のモリエル線図で説明すると、第１圧縮機１ａでＣＯ2冷媒が１００kg/cm2程度まで圧縮され（Ａ→Ｂ）、更に第１放熱器２ａで放熱され（Ｂ→Ｃ）、これが再度第２圧縮機１ｂで圧縮され１５０kg/cm2程度となる（Ｃ→Ｂ”）。この再圧縮されたＣＯ2冷媒は再度第２放熱器２ｂで放熱され（Ｂ”→Ｃ’）、更に膨張機構３ａで断熱膨張される（Ｃ’→Ｄ”）。この断熱膨張されたＣＯ2冷媒は蒸発器４で吸熱し（Ｄ”→Ａ）、室内冷房を行う。この図３でＡ→Ｂ→Ｃ→Ｄは従来例で説明した第１圧縮機１ａのみでＣＯ2冷媒を１００kg/cm2程度まで圧縮するときの冷媒変化（以下、従来例１という）、Ａ→Ｂ’→Ｃ’→Ｄ’は従来例で説明した第１圧縮機１ａのみでＣＯ2冷媒を１５０kg/cm2程度まで圧縮するときの冷媒変化（以下、従来例２という）をそれぞれ示している。
【００２５】
そこで、本実施形態に係る冷凍空調装置の冷却作用を従来例２に係る冷凍空調装置の冷却作用と比較して説明する。なお、図３で（ｈ）はエンタルピを示す。
【００２６】
即ち、従来例２の冷凍空調装置では圧縮機の動力は、（ｈＢ’ーｈＡ）＝（ｈＢーｈＡ）＋（ｈＢ’ーｈＢ）、一方、本実施形態に係る冷凍空調装置の各圧縮機１ａ，１ｂの動力は、（ｈＢーｈＡ）＋（ｈＢ”ーｈＣ）である。
【００２７】
ここで、従来例に係る（ｈＢ’ーｈＢ）をＷ１、（ｈＢ”ーｈＣ）をＷ２とするとき、Ｂ→Ｂ’への断熱圧縮に係る等エントロピ線とＣ→Ｂ”への断熱圧縮に係る等エントロピ線とを比較するとき、本実施形態に係る冷凍空調装置のＣ点におけるエンタルピがＢ点よりも小さくなっている分、その傾きが大きく、これにより、Ｗ１＞Ｗ２となる。
【００２８】
従って、本実施形態に係る冷凍空調装置は従来の冷凍空調装置と比較し、圧縮機１ａ，１ｂ全体の動力が小さくなっている。
【００２９】
また、本実施形態に係る冷凍空調装置の膨張機構３ａはＣＯ2冷媒を断熱膨張するため、等エントロピ線上に沿って変化し、Ｃ’→Ｄ”と変化する、これにより、冷凍効果が（ｈＡーｈＤ”）となり従来例２の冷凍効果（ｈＡーｈＤ’）よりも大きくなる。
【００３０】
更に、第２圧縮機１ｂの駆動軸と膨張機構３ａの出力軸をシャフト８で連結しているため、膨張機構３ａでの冷媒膨張作用に伴う動力が第２圧縮機１ｂの冷媒圧縮作用に利用される。
【００３１】
【発明の効果】
以上説明したように、本発明によれば、圧縮機全体の動力が小さくて済み、また、冷凍効果の大きな冷凍空調装置を実現することができる。
【００３２】
また、圧縮機の駆動軸と膨張機構の出力軸を連係し膨張機構での冷媒膨張作用に伴う動力を、他方の圧縮機の冷媒圧縮作用に利用でき、運転コストが安くなる。
【図面の簡単な説明】
【図１】本実施形態に係る冷凍空調装置の冷媒回路図
【図２】第２圧縮機と膨張機構との連係構造を示す概略図
【図３】本実施形態に係る冷凍空調装置のＣＯ2モリエル線図
【図４】従来の冷凍空調装置の冷媒回路図
【図５】従来の冷凍空調装置のＣＯ2モリエル線図
【符号の説明】
１ａ…第１圧縮機、１ｂ…圧縮機、２ａ…第１放熱器、２ｂ…第２放熱器、３ａ…膨張機構、４…蒸発器、５…冷媒管、６…バイパス管、７…逆止弁。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a refrigeration air conditioner that uses carbon dioxide as a refrigerant.
[0002]
[Prior art]
Conventionally, a refrigerating and air-conditioning apparatus shown in FIG. 4 is generally known as a refrigerating and air-conditioning apparatus that uses this type of carbon dioxide (CO 2 ) as a refrigerant.
[0003]
This refrigeration air conditioner has a compressor 1, a radiator 2, an expansion valve 3, and an evaporator 4, and carbon dioxide refrigerant is converted into an arrow with the compressor 1 → the radiator 2 → the expansion valve 3 → the evaporator 4 → the compressor 1. By sequentially circulating as shown, air conditioning such as indoor cooling is performed.
[0004]
[Problems to be solved by the invention]
By the way, in a refrigerating and air-conditioning apparatus using CO 2 refrigerant that releases heat to the atmosphere, a compression that provides a high discharge pressure to ensure a predetermined refrigerating capacity even when the outside air temperature is high. A machine is required.
[0005]
That is, if described in a CO 2 Mollier diagram of FIG. 5, in the normal operation, it is compressed by the compressor 1 to 100 kg / cm 2 beyond the critical point of the saturated liquid line and the saturated vapor line to compress the CO 2 refrigerant (A → B in FIG. 5). Next, the compressed CO 2 refrigerant is radiated to the atmosphere by the radiator 2 (B → C in FIG. 5), and the radiated CO 2 refrigerant is expanded along the isenthalpy line by the expansion valve 3 to reduce the pressure. (C → D in FIG. 5). The CO 2 refrigerant that has become wet steam due to this pressure drop is vaporized by the evaporator 4 to cool the room (D → A in FIG. 5).
[0006]
On the other hand, in order to obtain a sufficient cooling capacity even when the outside air temperature becomes high at 35 ° C., the CO 2 refrigerant must be circulated through A → B ′ → C ′ → D ′ in FIG. A discharge pressure of about 150 kg / cm 2 is required.
[0007]
Accordingly, in order to sufficiently cool the room even when the outside air temperature is high, it is necessary to install a compressor 1 having a large refrigerating capacity, and the efficiency of the driving power of the compressor 1 is low. It was a thing.
[0008]
An object of the present invention is to provide a refrigeration air-conditioning apparatus that improves the refrigeration effect without increasing the power of the entire compressor in view of the conventional problems.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the invention of claim 1 is a vapor which releases a heat from a radiator in a supercritical state by sequentially circulating a refrigerant of carbon dioxide to a compressor, a radiator, an expansion mechanism and an evaporator. In the compression-type refrigeration and air-conditioning apparatus, the radiator is composed of a first radiator and a second radiator sequentially connected in series, and another compressor is inserted between the radiators. The drive shaft of the compressor is linked to the output shaft of the expansion mechanism, and a bypass pipe that bypasses the other compressor by connecting the gas suction port and the gas discharge port of the other compressor is provided . .
[0010]
According to the present invention, the CO 2 refrigerant circulates in order of one compressor → the first radiator → the other compressor → the second radiator → the expansion mechanism → the evaporator → the one compressor to perform indoor cooling or the like. .
[0011]
In this refrigeration cycle, one compressor compresses to about 100 kg / cm 2 , and the other compressor compresses the refrigerant to about 150 kg / cm 2 to obtain a required discharge pressure. Here, the power of the other compressor (power consumed by the other compressor to increase the discharge pressure from 100 kg / cm 2 to 150 kg / cm 2 ) and the power of one compressor (100 kg for one compressor) compared to the power consumed to increase from 150 cm / cm 2 to 150 kg / cm 2 ), the refrigerant sucked into the other compressor is partly dissipated by the first radiator and the enthalpy is reduced (the other As the slope of the isentropic line in the compressor increases, the power decreases.
[0012]
Further, since the drive shaft of the compressor and the output shaft of the expansion mechanism are linked, the power accompanying the refrigerant expansion action in the expansion mechanism is used for the refrigerant compression action of the other compressor. Furthermore, when one compressor starts gas compression at the start of operation of the refrigeration air conditioner, the pressure at the outlet of the evaporator and the expansion mechanism drops, and the pressure increased by one compressor is a check valve, It is transmitted to the second radiator and the expansion mechanism inlet via the bypass pipe. As a result, the pressure difference between the outlet and the inlet of the expansion mechanism becomes a predetermined pressure difference, the expansion mechanism is driven, the driving force of the expansion mechanism is used as the driving force of the other compressor, and the other compressor is driven. To do. After the other compressor is driven, all the CO 2 refrigerant flows into the other compressor by the suction input of the other compressor, and performs indoor cooling and the like.
[0013]
According to a second aspect of the present invention, in the refrigerating and air-conditioning apparatus of the first aspect, the bypass pipe is provided with a check valve for restricting refrigerant flow from the gas discharge port to the gas suction port .
[0014]
According to this invention, by providing the check valve in the bypass pipe, the refrigerant discharged from the other compressor is prevented from returning through the bypass pipe.
[0015]
According to a third aspect of the present invention, in the refrigerating and air-conditioning apparatus of the first or second aspect, the other compressor and the expansion mechanism are constituted by a scroll type compression / expansion mechanism. According to the present invention, since the expansion mechanism adiabatically expands along the isentropic line, the enthalpy immediately before inhalation into the evaporator is reduced and the refrigeration effect is improved.
[0016]
Note that the other compressor and the expansion mechanism may be integrally formed so that both are unitized.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
1 to 3 show an embodiment of a refrigerating and air-conditioning apparatus according to the present invention. FIG. 1 is a refrigerant circuit diagram of the refrigerating and air-conditioning apparatus, and FIG. 2 is a schematic diagram showing a linkage structure between a second compressor and an expansion mechanism. FIG. 3 is a CO 2 Mollier diagram of the refrigeration air conditioner. The same components as those of the conventional example already described in FIGS. 4 and 5 are denoted by the same reference numerals.
[0018]
This refrigeration air conditioner uses CO 2 as a refrigerant, and as shown in FIG. 1, one compressor (hereinafter referred to as a first compressor) 1a, a first radiator 2a, and the other compressor (hereinafter referred to as a first compressor). (Referred to as a second compressor) 1b, a second radiator 2b, an expansion mechanism 3a, and an evaporator 4 are sequentially connected by a refrigerant pipe 5, and the CO 2 refrigerant is supplied to the first compressor 1 → the first radiator 2a → the second compressor. 1b → second radiator 2b → expansion mechanism 3a → evaporator 4 → first compressor 1a is circulated in order, and the room 4 is cooled by the endothermic action of the evaporator 4. Further, the refrigerant pipe 5 on the gas inlet side of the second compressor 1b and the refrigerant pipe 5 on the gas outlet side are connected by a bypass pipe 6, and this bypass pipe 6 bypasses the second compressor 1b. Yes. The bypass pipe 6 is provided with a check valve 7, and the check valve 7 regulates the CO 2 refrigerant discharged from the second compressor 1 b from returning through the bypass pipe 6. .
[0019]
In the refrigerating and air-conditioning apparatus thus configured, the second compressor 1b and the expansion mechanism 3a are configured as shown in FIG. That is, both the second compressor 1b and the expansion mechanism 3a employ scroll-type compression / expansion mechanisms. First, the second compressor 1b has a gas suction port 11 on the outside and a gas discharge port 12 in the center. The orbiting scroll 13 is rotated in the direction of the arrow in FIG. The CO 2 refrigerant flowing in from the suction port 11 is compressed between the fixed scroll 14 and discharged from the gas discharge port 12.
[0020]
On the other hand, the expansion mechanism 3a has a configuration opposite to that of the second compressor 1b, that is, has the gas discharge port 31 on the outside and the gas suction port 32 on the inside, respectively, and the orbiting scroll 33 in the direction of the arrow in FIG. The CO 2 refrigerant flowing in the gas suction port 32 by rotating counterclockwise) is expanded between the fixed scroll 34 and discharged from the gas discharge port 31.
[0021]
Further, the drive shaft of the second compressor 1b and the output shaft of the expansion mechanism 3a are connected by a shaft 8 as shown in FIG. 2, and the second compressor 1b is driven by the drive of the expansion mechanism 3a. The compressor 1b and the expansion mechanism 3a are unitized and formed integrally.
[0022]
Next, the drive state of the refrigerating and air-conditioning apparatus according to this embodiment will be described. First, when the first compressor 1a is operated, the CO 2 refrigerant is compressed, and further flows into the first radiator 2a to be radiated to the outdoors. The radiated CO 2 refrigerant flows through the bypass pipe 6 and into the second radiator 2b because the second compressor 1b is not yet driven. The CO 2 refrigerant that has flowed to the second radiator 2b is radiated again and flows toward the expansion mechanism 3a. Here, the gas pressure at the gas suction port 32 of the expansion mechanism 3a increases, while the pressure at the gas discharge port 31 and the evaporator 4 side of the expansion mechanism 3a decreases. The pressure difference with the outlet 31 becomes a predetermined pressure difference. Thus, CO 2 refrigerant flows from the gas inlet port 32 of the expansion mechanism 3a, together with the orbiting scroll 33 is rotated by the expansion force of the CO 2 refrigerant, CO 2 refrigerant is discharged from the gas discharge port 31 while adiabatically expanded .
[0023]
The rotation of the orbiting scroll 33 of the expansion mechanism 3a drives the second compressor 1b connected to the expansion mechanism 3a. Here, at the initial operation of the refrigeration air conditioner, the CO 2 refrigerant flows into the bypass pipe 6, but all the CO 2 refrigerant is sucked into the second compressor 1b by the driving of the second compressor 1b. The CO 2 refrigerant sucked into the second compressor 1b is adiabatically compressed again by the second compressor 1b, the compressed CO 2 refrigerant is radiated by the second radiator 2b, and further adiabatically expanded by the expansion mechanism 3a. Is done. The CO 2 refrigerant adiabatically expanded in this way exchanges heat with room air in the evaporator 4 and performs room cooling.
[0024]
The cooling cycle of the refrigerating and air-conditioning apparatus as described above will be described with reference to the Mollier diagram of FIG. 3. The CO 2 refrigerant is compressed to about 100 kg / cm 2 by the first compressor 1a (A → B), and further the first radiator. 2a is radiated (B → C), and is compressed again by the second compressor 1b to about 150 kg / cm 2 (C → B ″). This recompressed CO 2 refrigerant is again circulated by the second radiator 2b. The heat is dissipated (B ″ → C ′), and further adiabatically expanded by the expansion mechanism 3a (C ′ → D ″). This adiabatic expanded CO 2 refrigerant absorbs heat by the evaporator 4 (D ″ → A), Cool down. In FIG. 3, A → B → C → D is a change in refrigerant when the CO 2 refrigerant is compressed to about 100 kg / cm 2 only by the first compressor 1a described in the conventional example (hereinafter referred to as Conventional Example 1), A → B ′ → C ′ → D ′ respectively indicate the change in refrigerant (hereinafter referred to as Conventional Example 2) when the CO 2 refrigerant is compressed to about 150 kg / cm 2 by only the first compressor 1a described in the conventional example. Yes.
[0025]
Therefore, the cooling action of the refrigeration air conditioner according to the present embodiment will be described in comparison with the cooling action of the refrigeration air conditioner according to Conventional Example 2. In FIG. 3, (h) indicates enthalpy.
[0026]
That is, in the refrigeration air conditioner of Conventional Example 2, the power of the compressor is (hB′−hA) = (hB−hA) + (hB′−hB), while each compressor of the refrigeration air conditioner according to the present embodiment. The power of 1a and 1b is (hB−hA) + (hB ″ −hC).
[0027]
Here, when (hB′−hB) according to the conventional example is W1 and (hB ″ −hC) is W2, isentropic lines related to adiabatic compression from B → B ′ and adiabatic compression from C → B ″ When the enthalpy line is compared with the isentropic line, the enthalpy at the point C of the refrigerating and air-conditioning apparatus according to the present embodiment is smaller than the point B, so that the inclination is large, and thus W1> W2.
[0028]
Therefore, the refrigeration air conditioner according to the present embodiment has a smaller power of the compressors 1a and 1b than the conventional refrigeration air conditioner.
[0029]
Further, since the expansion mechanism 3a of the refrigerating and air-conditioning apparatus according to the present embodiment adiabatically expands the CO 2 refrigerant, the expansion mechanism 3a changes along the isentropic line and changes from C ′ → D ″. −hD ″), which is larger than the refrigeration effect (hA−hD ′) of Conventional Example 2.
[0030]
Further, since the drive shaft of the second compressor 1b and the output shaft of the expansion mechanism 3a are connected by the shaft 8, the power accompanying the refrigerant expansion action in the expansion mechanism 3a is used for the refrigerant compression action of the second compressor 1b. Is done.
[0031]
【The invention's effect】
As described above, according to the present invention, the power of the entire compressor can be reduced, and a refrigeration air conditioner with a large refrigeration effect can be realized.
[0032]
Further, the driving shaft of the compressor and the output shaft of the expansion mechanism are linked so that the power accompanying the refrigerant expansion action of the expansion mechanism can be used for the refrigerant compression action of the other compressor, and the operating cost is reduced.
[Brief description of the drawings]
A refrigerant circuit diagram of a refrigeration air conditioning system according to the disclosed exemplary embodiment [Fig. 2] CO 2 of the refrigerating and air-conditioning apparatus according to the schematic diagram FIG. 3 according to the embodiment shown an association structure between the expansion mechanism second compressor Mollier diagram [Fig. 4] Refrigerant circuit diagram of a conventional refrigeration air conditioner [Fig. 5] CO 2 Mollier diagram of a conventional refrigeration air conditioner [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1a ... 1st compressor, 1b ... Compressor, 2a ... 1st radiator, 2b ... 2nd radiator, 3a ... Expansion mechanism, 4 ... Evaporator, 5 ... Refrigerant pipe, 6 ... Bypass pipe, 7 ... Check valve.

Claims (4)

二酸化炭素の冷媒を圧縮機、放熱器、膨張機構及び蒸発器に順次循環し、超臨界状態で放熱器から熱を放出する蒸気圧縮式の冷凍空調装置において、
前記放熱器を順次直列に接続された第１放熱器と第２放熱器とから構成するとともに、該各放熱器の間に他の圧縮機を挿入し、該他の圧縮機の駆動軸と前記膨張機構の出力軸を連係し、
前記他の圧縮機のガス吸入口とガス吐出口を接続し該他方の圧縮機を迂回するバイパス管を設けた
ことを特徴とする冷凍空調装置。In a vapor compression refrigeration air conditioner that sequentially circulates a carbon dioxide refrigerant to a compressor, a radiator, an expansion mechanism, and an evaporator, and releases heat from the radiator in a supercritical state,
The radiator is composed of a first radiator and a second radiator sequentially connected in series, and another compressor is inserted between the radiators, and the drive shaft of the other compressor and the Link the output shaft of the expansion mechanism ,
A refrigerating and air-conditioning apparatus comprising a bypass pipe that connects a gas suction port and a gas discharge port of the other compressor and bypasses the other compressor . 前記バイパス管に該ガス吐出口から該ガス吸入口への冷媒流通を規制する逆止弁を設けた
ことを特徴とする請求項１記載の冷凍空調装置。The refrigerating and air-conditioning apparatus according to claim 1, wherein the bypass pipe is provided with a check valve for regulating refrigerant flow from the gas discharge port to the gas suction port . 前記他の圧縮機と前記膨張機構をスクロール式圧縮・膨張機構で構成した
ことを特徴とする請求項１又は請求項２記載の冷凍空調装置。The refrigerating and air-conditioning apparatus according to claim 1 or 2, wherein the other compressor and the expansion mechanism are configured by a scroll compression / expansion mechanism. 前記他の圧縮機と前記膨張機構とを一体に形成した
ことを特徴とする請求項１乃至請求項３の何れか１項記載の冷凍空調装置。The refrigerating and air-conditioning apparatus according to any one of claims 1 to 3, wherein the other compressor and the expansion mechanism are integrally formed.
JP25694697A 1997-09-22 1997-09-22 Refrigeration air conditioner Expired - Fee Related JP4031849B2 (en)

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JP3953871B2 (en) 2002-04-15 2007-08-08 サンデン株式会社 Refrigeration air conditioner
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JP4976970B2 (en) * 2007-09-27 2012-07-18 パナソニック株式会社 Refrigeration cycle equipment
JP4974851B2 (en) * 2007-11-01 2012-07-11 三菱電機株式会社 Refrigeration air conditioner
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