JP2004309027A - Control method for heat pump device - Google Patents

Control method for heat pump device Download PDF

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Publication number
JP2004309027A
JP2004309027A JP2003103973A JP2003103973A JP2004309027A JP 2004309027 A JP2004309027 A JP 2004309027A JP 2003103973 A JP2003103973 A JP 2003103973A JP 2003103973 A JP2003103973 A JP 2003103973A JP 2004309027 A JP2004309027 A JP 2004309027A
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Japan
Prior art keywords
pressure
evaporator
refrigerant
heat pump
pump device
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JP2003103973A
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Japanese (ja)
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JP2004309027A5 (en
Inventor
Yasushi Watabe
安司 渡部
Yoshitsugu Nishiyama
吉継 西山
Tetsuei Kuramoto
哲英 倉本
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Panasonic Holdings Corp
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Matsushita Electric Industrial Co Ltd
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Priority to JP2003103973A priority Critical patent/JP2004309027A/en
Publication of JP2004309027A publication Critical patent/JP2004309027A/en
Publication of JP2004309027A5 publication Critical patent/JP2004309027A5/ja
Pending legal-status Critical Current

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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
    • 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
    • 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
    • F25B2339/00—Details of evaporators; Details of condensers
    • F25B2339/04—Details of condensers
    • F25B2339/047—Water-cooled condensers
    • 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
    • F25B2600/00—Control issues
    • F25B2600/11—Fan speed control
    • F25B2600/112—Fan speed control of evaporator fans
    • 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
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/19—Pressures
    • F25B2700/193—Pressures of the compressor
    • F25B2700/1933—Suction pressures
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

<P>PROBLEM TO BE SOLVED: To avoid refrigeration cycle instability symptom occurring when the low pressure side refrigerant pressure of a heat pump device nears or exceeds a critical pressure. <P>SOLUTION: In the heat pump device formed by annularly connecting a compressor, a radiator, a pressure reducing device, and an evaporator through refrigerant pipes, a pressure detection means is installed between a pressure reducing device outlet and the compressor. When the refrigerant pressure nears or exceeds the critical pressure of the refrigerant used by the pressure detection means, a pressure in the evaporator is reduced by a heat absorption amount varying means reducing the refrigerating capacity of the evaporator. The heat absorption amount varying means reduces the speed of an evaporator side fan less than in a normal operation or stops the operation of the fan so that the evaporator can be stably operated even under overload conditions. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【産業上の利用分野】
本発明は、臨界圧力を超えた範囲で使用するヒートポンプ装置の制御方法に関するものである。
【０００２】
【従来の技術】
従来の技術として、ヒートポンプ装置は図７に示すような圧縮機１、放熱器（凝縮器）２、減圧装置３、蒸発器４を環状に接続して構成され、特に臨界圧力以上まで加圧される冷媒（例えば二酸化炭素）を使用した場合、このヒートポンプ装置のモリエル線図は図８となる。
【０００３】
【発明が解決しようとする課題】
ここで、日本での過負荷条件（４３℃）で蒸発器が空冷式のファンによって吸込空気から吸熱する場合、図２に示すようなモリエル線図となる。つまり、蒸発器内の圧力が臨界圧力Ｐｃに近づくことにより、蒸発潜熱△ｈｅが急激に減少する。この装置の圧縮機運転回転数、減圧装置の絞り開度、放熱量が一定とした場合、この吸熱側の過負荷条件により、蒸発器の能力は著しく低下し、吐出圧力及び吐出温度等の冷凍サイクルが不安定になる。更に、前記減圧装置の弁開度が電気的に調整可能な場合、吐出温度等の急激な変化によって弁開度の増減が発生し、圧力の増減を生じる。圧力の急増は、設計圧力の増大につながり冷凍サイクル部品の耐圧強化のため多大なコストを招き、また保安用の圧力スイッチにより高圧保護制御を行っている場合、頻繁に高圧保護制御が作動し、運転できないといった問題を生じる。
【０００４】
【課題を解決するための手段】
上記課題を解決するために、請求項１記載の本発明のヒートポンプ装置の制御方法は、圧縮機、放熱器、減圧装置、蒸発器を冷媒配管によって環状に接続して構成されるヒートポンプ装置において、前記減圧装置出口から前記圧縮機までの間に圧力検出手段を具備し、前記圧力検出手段が冷媒の臨界圧力に近づくまたは超えると、前記蒸発器の冷凍能力を減少させる吸熱量変化手段により前記蒸発器内の圧力を減少させるものであって、この吸熱量変化手段は、前記蒸発器のファン速度を通常運転より減少または停止させることを特徴とする。
【０００５】
請求項２記載の本発明のヒートポンプ装置の制御方法は、前記圧力検出手段は、前記冷媒配管に取りつけた温度検出手段であることを特徴とする。
【０００６】
請求項３記載の本発明のヒートポンプ装置の制御方法は、前記温度検出手段は、前記減圧装置と前記蒸発器の中間点との間に設けることを特徴とする。
【０００７】
請求項４記載の本発明のヒートポンプ装置の制御方法は、前記ヒートポンプ装置に使用される冷媒は、二酸化炭素であることを特徴とする。
【０００８】
【発明の実施の形態】
本発明の第１の実施の形態におけるヒートポンプ装置の制御方法は、圧力検出手段が冷媒の臨界圧力に近づくまたは超えると、蒸発器の冷凍能力を減少させる吸熱量変化手段により蒸発器内の圧力を減少させるものであって、前記吸熱量変化手段は、前記蒸発器のファンの速度を通常運転より減少または停止させるものである。これによれば、蒸発器の負荷が高い等によって発生する臨界圧力付近までの圧力上昇を未然に検知し、吸熱量を減少させることにより、蒸発器における蒸発潜熱を確保し、安定した運転が確保できる。その結果、蒸発器の負荷が高い状態でも急激な圧力上昇及び減少変化が発生せず、圧力容器や機能部品（電磁膨張弁、開閉弁等）の設計圧力低減が可能となり、信頼性確保の為のコスト増大（肉圧アップ等）を防止できる。吸熱量変化手段は、蒸発器に設けた既存部品を使用することが可能となり、機能付加によるコスト増大を防止することが可能である。
【０００９】
本発明の第２の実施の形態におけるヒートポンプ装置の制御方法は、圧力検出手段を前記冷媒配管に取りつけた温度検出手段とするものである。これによれば、冷媒２相域の温度を検出することにより圧力を推定可能とする為、圧力検出手段（圧力スイッチ、圧力センサ）等の複雑な構造及びシール機能を有しない安価な温度センサで、低圧側の圧力を推定することができる。
【００１０】
本発明の第３の実施の形態におけるヒートポンプ装置の制御方法は、温度検出手段は、前記減圧装置と前記蒸発器の中間点との間に設けるものである。これによれば、蒸発器の負荷が過負荷条件になったり、過渡的に蒸発器内の冷媒が過熱域となっても、常時冷媒２相域であるため、精度良く圧力を推定することができる。
【００１１】
本発明の第４の実施の形態におけるヒートポンプ装置の制御方法は、ヒートポンプ装置に使用される冷媒は、二酸化炭素である。この場合、サイクル内の圧力が冷媒の臨界圧力以上まで加圧されるが、低圧側部品を臨界圧力以下で運転することができ、急激な高圧上昇を防止することで高圧部品の設計圧力、更には耐圧部品を臨界圧力以下で運転することで低圧部品の設計圧力を各々抑制させ、圧力容器（蒸発器）や機能部品（膨張弁）のシステムコストを抑制することができる。
【００１２】
【実施例】
以下、本発明の実施例を図面に基づいて説明する。
【００１３】
（第１の実施例）
図１は、第一の実施例におけるヒートポンプ装置を示したものである。本実施例のヒートポンプ装置は、圧縮機１、放熱器２、減圧装置３、蒸発器４を冷媒配管５によって環状に接続して構成され、冷媒として二酸化炭素を使用している。
【００１４】
図２は、本装置におけるモリエル線図（ｐ−ｈ線図）を示したものである。圧縮機１は、吸引した冷媒を臨界圧力Ｐｃ以上まで圧縮して吐出し、吐出された高温高圧の冷媒は、貯湯槽６内から供給された液体（水）と放熱器２を介して熱交換される。放熱器２を流れる冷媒（二酸化炭素）は圧縮機１によって臨界圧力Ｐｃ以上に加圧されている為、放熱器２を通過する液体に放熱して温度低下しても凝縮（冷媒２相域）することはない。減圧装置３は、放熱器２から流出する冷媒（二酸化炭素）を減圧する装置のことで、毛細管によるキャピラリーチューブや制御装置によって弁開度を電気的に制御する電磁式膨張弁である。冷媒（二酸化炭素）は、この減圧装置３によって冷媒２相域となるまで減圧されたのち、蒸発器４によって吸熱冷媒が蒸発気化した後、再び圧縮機１に吸引される。しかし、図２に示すように、蒸発器側の負荷が過負荷条件（空冷の場合、吸込空気温度が４３℃以上、水冷の場合、入水温度が４５℃以上）となると、蒸発器内圧力△Ｐｅ（図２では減圧装置出口〜蒸発器入口での圧力）が臨界圧力Ｐｃに近づくことにより、蒸発潜熱△ｈｅが急激に減少する。この装置の圧縮機運転回転数、減圧装置の絞り開度、放熱量が一定とした場合、この吸熱側の過負荷条件により、蒸発器の能力は著しく低下し、吐出圧力及び吐出温度等の冷凍サイクルが不安定になる。更に、前記減圧装置の弁開度が電気的に調整可能な場合、吐出温度等の急激な変化によって弁開度の増減が発生し、更に圧力の増減を生じる。圧力の急増は、設計圧力の増大につながり冷凍サイクル部品の耐圧強化のため多大なコストを招き、また保安用の圧力スイッチにより高圧保護制御を行っている場合、頻繁に高圧保護制御が作動し、運転できないといった問題を生じる。このような課題を解決する為に、本発明は減圧装置３出口から圧縮機１までの低圧側に圧力検出手段１２を具備し、圧力検出手段１２が使用する冷媒の臨界圧力Ｐｃに近づくまたは超えると、マイクロコンピュータ１０により蒸発器側の冷凍能力を減少させる吸熱量変化手段（図１の場合、蒸発器側ファン１１）を通常運転時より減少または停止させることにより、蒸発器４内の圧力を減少させ、定格条件に近い蒸発圧力Ｐｅ１を得ることができ、圧縮機の吐出・吸入における圧力及び温度を安定して運転させることができる。
【００１５】
なお、吸熱量変化手段は、水冷における蒸発器４側ポンプの速度を減少または停止させたり、蒸発器４の開口面積を減少させたり、吸熱負荷より低い媒体を付加（例えば、冷却水噴霧等）する付加手段も同様の効果がある。
【００１６】
（第２の実施例）
図３は、第２の実施例におけるヒートポンプ装置を示したものである。図１の圧力検出手段１２に対して、低圧側ヒートポンプ装置の冷媒配管５に温度検出手段１３を設ける構成である。これによれば、冷媒２相域の温度を検出することにより圧力を推定可能となる為、圧力検出手段（圧力スイッチ、圧力センサ）等の複雑な構造及びシール機能を有しない安価な温度センサで、低圧側の圧力を推定することができる。また、除霜用センサと共用化することでコストアップ無く安価な装置を提供することが可能となる。
【００１７】
（第３の実施例）
図４は、第３の実施例におけるヒートポンプ装置を示したものである。本発明は、温度検出手段１３が、減圧装置３と蒸発器３の中間点との間に設ける構成となる。ここで本実施例の作用を図５及び図６を用いて説明する。図５は、ヒートポンプ装置における圧縮機１等の機能部品が動作し、冷凍サイクルの各部の圧力及び温度が安定した状態を示したものであり、図６は、圧縮機１が起動した時や負荷が急変した場合の過渡的な状態を示したものである。図５より、使用される冷媒が二酸化炭素で安定した状態の場合、圧縮機１から吐出された高温高圧の冷媒は放熱器２の入口から減圧装置入口３−ａまで臨界圧力域の冷媒状態となり、減圧装置３により気液２相の冷媒状態１５−ｂとなり、蒸発器４により冷媒は蒸発し、蒸発器４を出た後、冷媒は気相域１５−ｃとなり圧縮機１に吸引されるため、温度検出手段１３−ａにより、気液二相域の冷媒温度を検出することにより、低圧側圧力を推定することが可能である。しかし、図６のような蒸発器側の負荷が高くなる過負荷条件では、図２で説明した通り、蒸発器４内の圧力が臨界圧力Ｐｃに近づき蒸発潜熱△Ｐｅが減少する為に、蒸発器中間点から蒸発器出口まで気相域の冷媒状態１５−ｃとなり、安定した運転状態でも温度検出手段１３−ａでは、冷媒気相（過熱）域での温度を検出することができず、正確な圧力を推定することができない。そこで、減圧装置出口３−ｂと蒸発器の中間点４−ａとの間に温度検出手段１３−ｂを設けることにより、過負荷における安定運転状態や圧縮機起動等の過渡運転時でも、気液二相域冷媒状態における温度を検出し正確な圧力を推定することが可能となる。したがって、使用する冷媒が二酸化炭素のような過負荷時に低圧側圧力が臨界圧力に近づく二酸化炭素のような冷媒でも、温度検出手段１３−ｂにより低圧側ヒートポンプ装置の圧力を推定し、吸熱量変化手段、すなわち吸熱側ファン１１の速度を減少または停止させることにより、安定運転可能な圧力まで低圧側ヒートポンプ装置の圧力を減少させることが可能である。なお、第１〜３実施例に示したように、貯湯槽６内の液体は、給湯用に用いるだけではなく、床暖房用、室内空調用としても使用して良く、また、放熱器２の放熱手段として貯湯槽６の液体を用いず、ファン１４により放熱しても良い。
【００１８】
更に、圧縮機１の冷媒吸込側に冷媒を貯留するアキュムレータが設置されていても、第１〜３実施例の効果は同様に得られる。
【００１９】
また、減圧装置３において弁開度を電気的に制御可能な電磁式膨張弁によって、蒸発器４内の圧力を減圧することが可能であるが、その際、吐出圧力が急増するため、得策ではない。
【００２０】
【発明の効果】
上記の実施例から明らかなように、本発明は、臨界圧力を超える冷媒を使用するヒートポンプ装置において、様々な負荷に対して安定した冷凍サイクル制御をコストの増大を可能な限り伴わない手段で可能とするものである。
【図面の簡単な説明】
【図１】本発明の第１の実施例におけるヒートポンプ装置の冷凍サイクル図
【図２】本発明の第１の実施例における運転動作の説明図
【図３】本発明の第２の実施例におけるヒートポンプ装置の冷凍サイクル図
【図４】本発明の第３の実施例におけるヒートポンプ装置の冷凍サイクル図
【図５】本発明の第３の実施例におけるヒートポンプ装置の標準負荷・定格運転時の冷媒状態説明図
【図６】本発明の第３の実施例におけるヒートポンプ装置の過負荷条件・定格運転時の冷媒状態説明図
【図７】従来の実施例におけるヒートポンプ装置の冷凍サイクル図
【図８】従来の実施例における運転動作の説明図
【符号の説明】
１ 圧縮機
２ 放熱器
３ 減圧装置
３−ａ 減圧装置入口
３−ｂ 減圧装置出口
４ 蒸発器（蒸発器）
４−ａ 蒸発器中間点
５ 冷媒配管
６ 貯湯槽
７ ポンプ（ウォーターポンプ）
８ 水配管
１０ マイクロコンピュータ（制御部）
１１ 蒸発器側ファン
１２ 圧力検出手段
１３ 温度検出手段（センサ）
１３−ａ 温度検出手段（請求項２の手段）
１３−ｂ 温度検出手段（請求項３の手段）
１４ 放熱器側ファン
１５ 管内冷媒状態（二酸化炭素）
１５−ａ 臨界圧力域の冷媒状態
１５−ｂ 気液二相域の冷媒状態
１５−ｃ 気相（過熱）域の冷媒状態[0001]
[Industrial applications]
The present invention relates to a method for controlling a heat pump device used in a range exceeding a critical pressure.
[0002]
[Prior art]
As a conventional technique, a heat pump device is configured by connecting a compressor 1, a radiator (condenser) 2, a pressure reducing device 3, and an evaporator 4 in a ring shape as shown in FIG. When a refrigerant (for example, carbon dioxide) is used, a Mollier diagram of this heat pump device is shown in FIG.
[0003]
[Problems to be solved by the invention]
Here, when the evaporator absorbs heat from the intake air by an air-cooled fan under overload conditions (43 ° C.) in Japan, a Mollier diagram as shown in FIG. 2 is obtained. That is, when the pressure in the evaporator approaches the critical pressure Pc, the latent heat of evaporation △ he sharply decreases. If the compressor operation speed of this device, the throttle opening of the pressure reducing device, and the amount of heat radiation are constant, the overload condition on the heat absorption side will significantly reduce the capacity of the evaporator and reduce the refrigeration such as discharge pressure and discharge temperature. The cycle becomes unstable. Further, when the valve opening of the pressure reducing device is electrically adjustable, the valve opening is increased or decreased due to a sudden change in the discharge temperature or the like, and the pressure is increased or decreased. The sudden increase in pressure leads to an increase in the design pressure, resulting in a large cost for strengthening the withstand pressure of the refrigeration cycle parts.When the high pressure protection control is performed by the pressure switch for security, the high pressure protection control is frequently activated. A problem such as inability to drive occurs.
[0004]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, a control method of a heat pump device according to the present invention according to claim 1 is a heat pump device configured by connecting a compressor, a radiator, a decompression device, and an evaporator in a ring by a refrigerant pipe. A pressure detecting means between the outlet of the pressure reducing device and the compressor, wherein when the pressure detecting means approaches or exceeds the critical pressure of the refrigerant, the heat absorption amount changing means for reducing the refrigerating capacity of the evaporator causes the evaporation to occur. The endothermic pressure changing means reduces or stops the fan speed of the evaporator from a normal operation.
[0005]
According to a second aspect of the present invention, in the control method of the heat pump device, the pressure detecting means is a temperature detecting means attached to the refrigerant pipe.
[0006]
According to a third aspect of the present invention, in the control method of the heat pump device, the temperature detecting means is provided between the pressure reducing device and an intermediate point of the evaporator.
[0007]
According to a fourth aspect of the present invention, in the control method of the heat pump device, the refrigerant used in the heat pump device is carbon dioxide.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
In the control method of the heat pump device according to the first embodiment of the present invention, when the pressure detection unit approaches or exceeds the critical pressure of the refrigerant, the pressure in the evaporator is changed by the heat absorption amount changing unit that reduces the refrigeration capacity of the evaporator. The heat absorption amount changing means reduces or stops the speed of the fan of the evaporator from the normal operation. According to this, the pressure rise near the critical pressure generated due to the high load of the evaporator, etc. is detected beforehand, and the amount of heat absorbed is reduced, thereby securing the latent heat of evaporation in the evaporator and ensuring stable operation. it can. As a result, even when the load on the evaporator is high, there is no sudden increase or decrease in pressure, and the design pressure of the pressure vessel and functional parts (electromagnetic expansion valve, on-off valve, etc.) can be reduced, and reliability is ensured. Cost increase (such as an increase in meat pressure) can be prevented. As the heat absorption amount changing means, it is possible to use existing parts provided in the evaporator, and it is possible to prevent an increase in cost due to the addition of a function.
[0009]
In the control method of the heat pump device according to the second embodiment of the present invention, the pressure detecting means is a temperature detecting means attached to the refrigerant pipe. According to this, since the pressure can be estimated by detecting the temperature of the refrigerant two-phase region, an inexpensive temperature sensor having no complicated structure such as pressure detecting means (pressure switch, pressure sensor) and a sealing function is used. , The pressure on the low pressure side can be estimated.
[0010]
In the control method of the heat pump device according to the third embodiment of the present invention, the temperature detecting means is provided between the pressure reducing device and an intermediate point of the evaporator. According to this, even if the load of the evaporator is in an overload condition or the refrigerant in the evaporator is transiently overheated, the pressure is accurately estimated because it is always in the refrigerant two-phase region. it can.
[0011]
In the control method of the heat pump device according to the fourth embodiment of the present invention, the refrigerant used in the heat pump device is carbon dioxide. In this case, the pressure in the cycle is pressurized to the critical pressure of the refrigerant or higher, but the low-pressure side component can be operated at the critical pressure or lower, and by preventing a sudden high pressure rise, the design pressure of the high-pressure component, By operating the pressure-resistant parts at a critical pressure or less, the design pressure of the low-pressure parts can be suppressed, and the system cost of the pressure vessel (evaporator) and the functional parts (expansion valve) can be suppressed.
[0012]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0013]
(First embodiment)
FIG. 1 shows a heat pump device according to the first embodiment. The heat pump device of the present embodiment is configured by connecting a compressor 1, a radiator 2, a decompression device 3, and an evaporator 4 in a ring shape by a refrigerant pipe 5, and uses carbon dioxide as a refrigerant.
[0014]
FIG. 2 is a Mollier diagram (ph diagram) of the present apparatus. The compressor 1 compresses the sucked refrigerant to a pressure higher than the critical pressure Pc and discharges the refrigerant. The discharged high-temperature and high-pressure refrigerant exchanges heat with the liquid (water) supplied from the hot water storage tank 6 through the radiator 2. Is done. Since the refrigerant (carbon dioxide) flowing through the radiator 2 is pressurized by the compressor 1 to a pressure equal to or higher than the critical pressure Pc, the refrigerant radiates heat to the liquid passing through the radiator 2 and condenses even if the temperature decreases (two-phase refrigerant region) I will not. The decompression device 3 is a device that decompresses refrigerant (carbon dioxide) flowing out of the radiator 2, and is an electromagnetic expansion valve that electrically controls a valve opening degree by a capillary tube formed by a capillary tube or a control device. After the refrigerant (carbon dioxide) is decompressed by the decompression device 3 until it reaches the refrigerant two-phase region, the endothermic refrigerant is evaporated and vaporized by the evaporator 4 and then sucked into the compressor 1 again. However, as shown in FIG. 2, when the load on the evaporator side becomes an overload condition (in the case of air cooling, the intake air temperature is 43 ° C. or higher, and in the case of water cooling, the inlet water temperature is 45 ° C. or higher), the pressure in the evaporator △ When Pe (in FIG. 2, the pressure from the outlet of the pressure reducing device to the inlet of the evaporator) approaches the critical pressure Pc, the latent heat of evaporation △ he sharply decreases. If the compressor operation speed of this device, the throttle opening of the pressure reducing device, and the amount of heat radiation are constant, the overload condition on the heat absorption side will significantly reduce the capacity of the evaporator and reduce the refrigeration such as discharge pressure and discharge temperature. The cycle becomes unstable. Further, when the valve opening of the pressure reducing device is electrically adjustable, the valve opening is increased or decreased due to a sudden change in the discharge temperature or the like, and the pressure is further increased or decreased. The sudden increase in pressure leads to an increase in the design pressure, resulting in a large cost for strengthening the withstand pressure of the refrigeration cycle parts.When the high pressure protection control is performed by the pressure switch for security, the high pressure protection control is frequently activated. A problem such as inability to drive occurs. In order to solve such a problem, the present invention includes a pressure detecting means 12 on the low pressure side from the outlet of the pressure reducing device 3 to the compressor 1, and approaches or exceeds the critical pressure Pc of the refrigerant used by the pressure detecting means 12. The pressure in the evaporator 4 is reduced by reducing or stopping the heat absorption amount changing means (in FIG. 1, the evaporator-side fan 11) for reducing the refrigerating capacity on the evaporator side from the normal operation by the microcomputer 10. The evaporating pressure Pe1 close to the rated condition can be obtained by reducing the pressure, and the pressure and temperature at the discharge and suction of the compressor can be stably operated.
[0015]
The endothermic amount changing means reduces or stops the speed of the evaporator 4 side pump in water cooling, reduces the opening area of the evaporator 4, and adds a medium lower than the endothermic load (for example, cooling water spray). The additional means having the same effect has the same effect.
[0016]
(Second embodiment)
FIG. 3 shows a heat pump device according to the second embodiment. In contrast to the pressure detecting means 12 of FIG. 1, a temperature detecting means 13 is provided in the refrigerant pipe 5 of the low-pressure side heat pump device. According to this, since the pressure can be estimated by detecting the temperature of the refrigerant two-phase region, an inexpensive temperature sensor having no complicated structure such as pressure detecting means (pressure switch, pressure sensor) and the like and no sealing function is used. , The pressure on the low pressure side can be estimated. In addition, it is possible to provide an inexpensive device without increasing the cost by sharing the sensor with the defrosting sensor.
[0017]
(Third embodiment)
FIG. 4 shows a heat pump device according to the third embodiment. The present invention has a configuration in which the temperature detecting means 13 is provided between the pressure reducing device 3 and an intermediate point of the evaporator 3. Here, the operation of this embodiment will be described with reference to FIGS. FIG. 5 shows a state where the functional components such as the compressor 1 in the heat pump device operate and the pressure and temperature of each part of the refrigeration cycle are stabilized. FIG. Shows a transitional state when a sudden change occurs. From FIG. 5, when the refrigerant used is stable with carbon dioxide, the high-temperature and high-pressure refrigerant discharged from the compressor 1 is in a critical pressure region from the inlet of the radiator 2 to the pressure reducing device inlet 3-a. Then, the refrigerant becomes a gas-liquid two-phase refrigerant state 15-b by the pressure reducing device 3, the refrigerant evaporates by the evaporator 4, and after leaving the evaporator 4, the refrigerant becomes a gas phase region 15-c and is sucked into the compressor 1. Therefore, the low pressure side pressure can be estimated by detecting the refrigerant temperature in the gas-liquid two-phase region by the temperature detecting means 13-a. However, under the overload condition in which the load on the evaporator side is increased as shown in FIG. 6, the pressure in the evaporator 4 approaches the critical pressure Pc and the latent heat of evaporation 蒸 発 Pe decreases, as described with reference to FIG. The refrigerant state 15-c in the gaseous phase region from the middle point of the evaporator to the outlet of the evaporator is obtained, and even in a stable operation state, the temperature detecting means 13-a cannot detect the temperature in the refrigerant gaseous phase (overheating) region, Precise pressure cannot be estimated. Therefore, by providing the temperature detecting means 13-b between the decompression device outlet 3-b and the intermediate point 4-a of the evaporator, the temperature can be reduced even in a stable operation state under overload or during a transient operation such as starting the compressor. It is possible to detect the temperature in the state of the liquid two-phase region refrigerant and estimate the pressure accurately. Therefore, even if the refrigerant to be used is a refrigerant such as carbon dioxide whose low pressure side pressure approaches the critical pressure at the time of overload such as carbon dioxide, the pressure of the low pressure side heat pump device is estimated by the temperature detecting means 13-b, and the heat absorption amount change. By reducing or stopping the speed of the heat-absorbing side fan 11, it is possible to reduce the pressure of the low-pressure side heat pump device to a pressure at which stable operation is possible. In addition, as shown in the first to third embodiments, the liquid in the hot water storage tank 6 may be used not only for hot water supply but also for floor heating and indoor air conditioning. The heat may be dissipated by the fan 14 without using the liquid in the hot water tank 6 as the heat dissipating means.
[0018]
Further, even if an accumulator for storing the refrigerant is provided on the refrigerant suction side of the compressor 1, the effects of the first to third embodiments can be similarly obtained.
[0019]
In addition, the pressure in the evaporator 4 can be reduced by an electromagnetic expansion valve capable of electrically controlling the valve opening in the pressure reducing device 3, but at this time, the discharge pressure rapidly increases. Absent.
[0020]
【The invention's effect】
As is apparent from the above embodiment, in the heat pump device using the refrigerant exceeding the critical pressure, the present invention enables stable refrigeration cycle control for various loads by means that does not involve an increase in cost as much as possible. It is assumed that.
[Brief description of the drawings]
FIG. 1 is a refrigeration cycle diagram of a heat pump device according to a first embodiment of the present invention. FIG. 2 is an explanatory diagram of an operation in the first embodiment of the present invention. FIG. FIG. 4 is a refrigeration cycle diagram of the heat pump device according to the third embodiment of the present invention. FIG. 5 is a refrigerant state at a standard load and rated operation of the heat pump device according to the third embodiment of the present invention. FIG. 6 is an explanatory diagram of a refrigerant state at the time of overload condition and rated operation of the heat pump device according to the third embodiment of the present invention. FIG. 7 is a refrigeration cycle diagram of the heat pump device according to the conventional embodiment. Explanatory drawing of the driving operation in the embodiment of the present invention.
DESCRIPTION OF SYMBOLS 1 Compressor 2 Radiator 3 Decompression device 3-a Decompression device inlet 3-b Decompression device outlet 4 Evaporator (evaporator)
4-a middle point of evaporator 5 refrigerant pipe 6 hot water storage tank 7 pump (water pump)
8 water piping 10 microcomputer (control unit)
11 evaporator side fan 12 pressure detecting means 13 temperature detecting means (sensor)
13-a Temperature detecting means (means of claim 2)
13-b Temperature detecting means (means of claim 3)
14 Radiator side fan 15 Refrigerant state in pipe (carbon dioxide)
15-a Refrigerant state in critical pressure region 15-b Refrigerant state in gas-liquid two-phase region 15-c Refrigerant state in gas phase (overheated) region

Claims (4)

圧縮機、放熱器、減圧装置、蒸発器を冷媒配管によって環状に接続して構成されるヒートポンプ装置において、前記減圧装置出口から前記圧縮機までの間に圧力検出手段を具備し、前記圧力検出手段が冷媒の臨界圧力に近づくまたは超えると、前記蒸発器の冷凍能力を減少させる吸熱量変化手段により前記蒸発器内の圧力を減少させるものであって、この吸熱量変化手段は、前記蒸発器のファン速度を通常運転より減少または停止させることを特徴とするヒートポンプ装置の制御方法。In a heat pump device configured by connecting a compressor, a radiator, a decompression device, and an evaporator in a ring by a refrigerant pipe, the heat pump device includes a pressure detection unit between an outlet of the decompression device and the compressor, and the pressure detection unit When the pressure approaches or exceeds the critical pressure of the refrigerant, the pressure in the evaporator is reduced by endothermic amount changing means for reducing the refrigerating capacity of the evaporator, and the endothermic amount changing means A method for controlling a heat pump device, wherein a fan speed is reduced or stopped from a normal operation. 前記圧力検出手段は、前記冷媒配管に取りつけた温度検出手段であることを特徴とする請求項１記載のヒートポンプ装置の制御方法。The control method for a heat pump device according to claim 1, wherein the pressure detecting means is a temperature detecting means attached to the refrigerant pipe. 前記温度検出手段は、前記減圧装置と前記蒸発器の中間点との間に設けることを特徴とする請求項２記載のヒートポンプ装置の制御方法。3. The method according to claim 2, wherein the temperature detecting means is provided between the pressure reducing device and an intermediate point of the evaporator. 前記ヒートポンプ装置に使用される冷媒は、二酸化炭素であることを特徴とする請求項１〜３のいずれか１項に記載のヒートポンプ装置の制御方法。The method for controlling a heat pump device according to claim 1, wherein the refrigerant used in the heat pump device is carbon dioxide.
JP2003103973A 2003-04-08 2003-04-08 Control method for heat pump device Pending JP2004309027A (en)

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007524059A (en) * 2003-06-23 2007-08-23 キャリア　コーポレイション Refrigeration system with variable speed fan
WO2010043829A2 (en) * 2008-10-17 2010-04-22 Orhan Togrul Heat pump
FR2937410A1 (en) * 2008-10-17 2010-04-23 Orhan Togrul Heat pump for transporting e.g. refrigerant, in e.g. building, has compressor protection kit collecting excess energy to protect movement setting unit, with temperature of fluid at suction compatible with characteristics of compressor
US20120131933A1 (en) * 2009-05-01 2012-05-31 Lg Electronics Inc. Air conditioner and method for operating same
EP2952833A3 (en) * 2014-05-16 2016-04-06 Lennox Industries Inc. Compressor operation management in air conditioners
GB2546586A (en) * 2015-11-19 2017-07-26 G A H (Refrigeration) Ltd Refrigeration system and method
JPWO2016189810A1 (en) * 2015-05-28 2018-03-15 パナソニックＩｐマネジメント株式会社 Heat pump equipment
JPWO2016189813A1 (en) * 2015-05-28 2018-03-15 パナソニックＩｐマネジメント株式会社 Heat pump equipment

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007524059A (en) * 2003-06-23 2007-08-23 キャリア　コーポレイション Refrigeration system with variable speed fan
WO2010043829A2 (en) * 2008-10-17 2010-04-22 Orhan Togrul Heat pump
FR2937410A1 (en) * 2008-10-17 2010-04-23 Orhan Togrul Heat pump for transporting e.g. refrigerant, in e.g. building, has compressor protection kit collecting excess energy to protect movement setting unit, with temperature of fluid at suction compatible with characteristics of compressor
WO2010043829A3 (en) * 2008-10-17 2010-08-26 Orhan Togrul Heat pump
US20120131933A1 (en) * 2009-05-01 2012-05-31 Lg Electronics Inc. Air conditioner and method for operating same
US9109809B2 (en) * 2009-05-01 2015-08-18 Lg Electronics Inc. Method of conditioning air with a refrigeration loop connected to a water circuit
EP2952833A3 (en) * 2014-05-16 2016-04-06 Lennox Industries Inc. Compressor operation management in air conditioners
US9482454B2 (en) 2014-05-16 2016-11-01 Lennox Industries Inc. Compressor operation management in air conditioners
JPWO2016189810A1 (en) * 2015-05-28 2018-03-15 パナソニックＩｐマネジメント株式会社 Heat pump equipment
JPWO2016189813A1 (en) * 2015-05-28 2018-03-15 パナソニックＩｐマネジメント株式会社 Heat pump equipment
GB2546586A (en) * 2015-11-19 2017-07-26 G A H (Refrigeration) Ltd Refrigeration system and method
GB2546586B (en) * 2015-11-19 2020-05-20 G A H Refrigeration Ltd Method and system for controlling performance of an evaporator of a refrigeration system

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