JP7019070B2 - Air conditioner - Google Patents

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JP7019070B2
JP7019070B2 JP2020556504A JP2020556504A JP7019070B2 JP 7019070 B2 JP7019070 B2 JP 7019070B2 JP 2020556504 A JP2020556504 A JP 2020556504A JP 2020556504 A JP2020556504 A JP 2020556504A JP 7019070 B2 JP7019070 B2 JP 7019070B2
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expansion valve
temperature
refrigerant
outside air
opening degree
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JPWO2020100228A1 (en
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大輔 伊東
拓未 西山
健太 村田
幹 佐藤
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Mitsubishi Electric 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
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • 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
    • 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
    • F25B13/00—Compression machines, plants or systems, with reversible cycle
    • 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
    • F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
    • F25B2313/031—Sensor arrangements
    • F25B2313/0314—Temperature sensors near the indoor heat exchanger
    • 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
    • F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
    • F25B2313/031—Sensor arrangements
    • F25B2313/0315—Temperature sensors near the outdoor heat exchanger
    • 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
    • F25B2500/00—Problems to be solved
    • F25B2500/19—Calculation of parameters
    • 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
    • F25B2600/25—Control of valves
    • F25B2600/2513—Expansion valves
    • 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
    • F25B2700/1931—Discharge pressures
    • 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
    • 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
    • F25B2700/21—Temperatures
    • F25B2700/2106—Temperatures of fresh outdoor air
    • 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
    • F25B2700/21—Temperatures
    • F25B2700/2115—Temperatures of a compressor or the drive means therefor
    • F25B2700/21151—Temperatures of a compressor or the drive means therefor at the suction side of the compressor
    • 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
    • F25B2700/21—Temperatures
    • F25B2700/2115—Temperatures of a compressor or the drive means therefor
    • F25B2700/21152—Temperatures of a compressor or the drive means therefor at the discharge side of the compressor
    • 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
    • F25B2700/21—Temperatures
    • F25B2700/2116—Temperatures of a condenser

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Air Conditioning Control Device (AREA)

Description

本発明は、空気調和機に関する。 The present invention relates to an air conditioner.

ＨＣ冷媒は、地球温暖化係数が小さい冷媒として知られている。特許文献１（特開平１１－２３０６２６号公報）には、ＨＣ（Hydrocarbon）冷媒を含む混合冷媒を用いた冷凍サイクル装置が記載されている。特許文献１では、この混合冷媒を用いたときに、圧縮機の吐出温度が高くなるのを回避するために、吐出温度が予め設定された設定温度以下になるように、膨張弁の開度を調整することが記載されている。 The HC refrigerant is known as a refrigerant having a small global warming potential. Patent Document 1 (Japanese Unexamined Patent Publication No. 11-23626) describes a refrigerating cycle apparatus using a mixed refrigerant containing an HC (Hydrocarbon) refrigerant. In Patent Document 1, in order to prevent the discharge temperature of the compressor from becoming high when this mixed refrigerant is used, the opening degree of the expansion valve is set so that the discharge temperature becomes equal to or lower than a preset set temperature. It is stated that adjustments will be made.

特開平１１－２３０６２６号公報Japanese Unexamined Patent Publication No. 11-23626

しかしながら、特許文献１のように、ＨＣ冷媒を用いて、吐出温度が設定温度以下となるように制御した場合には、圧縮機の吐出過熱度が過大、かつ圧縮機の吸入温度および吸入過熱度が過小となる。その結果、ＨＣ冷媒を用いると、ＨＦＣ（Hydrofluorocarbon）冷媒の一種であるＲ３２よりも、ＣＯＰ（Coefficient Of Performance）が低下するという問題がある。 However, as in Patent Document 1, when the discharge temperature is controlled to be equal to or lower than the set temperature by using the HC refrigerant, the discharge superheat degree of the compressor is excessive, and the suction temperature and the suction superheat degree of the compressor are excessive. Becomes too small. As a result, when an HC refrigerant is used, there is a problem that the COP (Coefficient Of Performance) is lower than that of R32, which is a kind of HFC (Hydrofluorocarbon) refrigerant.

それゆえに、本発明の目的は、地球温暖化係数が小さいＨＣ冷媒を用い、かつＲ３２を用いたときよりもＣＯＰを高くすることができる空気調和機を提供することである。 Therefore, an object of the present invention is to provide an air conditioner capable of using an HC refrigerant having a small global warming potential and having a higher COP than when using R32.

本発明の空気調和機は、圧縮機と、凝縮器と、膨張弁と、蒸発器とを含み、冷媒を循環させるように構成された冷媒回路と、圧縮機への冷媒の吸入温度を検出するように構成された第１のセンサと、外気温度を検出するように構成された第２のセンサとを備える。冷媒は、Ｒ２９０およびＲ１２７０のうちの少なくとも一方を含む。暖房運転時に、吸入温度と外気温度との差が（－２．０℃）を下回ると、膨張弁の開度が減少し、差が（＋０．６℃）を超えるときに、膨張弁の開度が増加する。 The air conditioner of the present invention includes a compressor, a condenser, an expansion valve, an evaporator, a refrigerant circuit configured to circulate the refrigerant, and detects the suction temperature of the refrigerant into the compressor. A first sensor configured as described above and a second sensor configured to detect the outside air temperature are provided. The refrigerant comprises at least one of R290 and R1270. During heating operation, when the difference between the suction temperature and the outside air temperature is less than (-2.0 ° C), the opening of the expansion valve decreases, and when the difference exceeds (+ 0.6 ° C), the expansion valve is opened. The degree increases.

本発明によれば、地球温暖化係数が小さいＨＣ冷媒を用い、かつＲ３２を用いたときよりもＣＯＰを高くすることができる。 According to the present invention, the COP can be made higher than that when the HC refrigerant having a small global warming potential is used and R32 is used.

実施の形態１に係る空気調和機の構成を表わす図である。It is a figure which shows the structure of the air conditioner which concerns on Embodiment 1. FIG. 制御装置６０と、制御装置６０と接続される構成要素を表わす図である。It is a figure which shows the control device 60, and the component which is connected to the control device 60. 冷房運転時の冷媒回路７０内の冷媒の流れを表わす図である。It is a figure which shows the flow of the refrigerant in the refrigerant circuit 70 at the time of a cooling operation. 暖房運転時の冷媒回路７０内の冷媒の流れを表わす図である。It is a figure which shows the flow of the refrigerant in the refrigerant circuit 70 at the time of a heating operation. 吸入過熱度ＳＨｓと理論ＣＯＰとの関係を表わす図である。It is a figure which shows the relationship between the inhalation superheat degree SHs, and the theoretical COP. 外気温度ＴＯと規格化ＣＯＰとの関係を表わす図である。It is a figure which shows the relationship between the outside air temperature TO and the normalized COP. （ａ）～（ｃ）は、Ｒ２９０とＲ３２における吸入温度ＴＳと規格化ＣＯＰとの関係を表わす図である。(A) to (c) are diagrams showing the relationship between the suction temperature TS and the normalized COP in R290 and R32. 実施の形態１の暖房運転時の空気調和機の制御手順を表わすフローチャートである。It is a flowchart which shows the control procedure of the air conditioner at the time of the heating operation of Embodiment 1. FIG. 実施の形態２の暖房運転時の空気調和機の制御手順を表わすフローチャートである。It is a flowchart which shows the control procedure of the air conditioner at the time of the heating operation of Embodiment 2. （ａ）～（ｃ）は、Ｒ２９０とＲ３２における吐出過熱度ＳＨｄと規格化ＣＯＰとの関係を表わす図である。(A) to (c) are diagrams showing the relationship between the discharge superheat degree SHd and the normalized COP in R290 and R32. Ｒ３２のＣＯＰよりもＲ２９０のＣＯＰが高くなり、かつ圧縮機１が液バック運転しない吐出過熱度ＳＨｄの範囲を表わす図である。It is a figure which shows the range of the discharge superheat degree SHd which the COP of R290 becomes higher than the COP of R32, and the compressor 1 does not perform a liquid back operation. 実施の形態３の暖房運転時の空気調和機の制御手順を表わすフローチャートである。It is a flowchart which shows the control procedure of the air conditioner at the time of the heating operation of Embodiment 3.

以下、実施の形態について、図面を参照して説明する。
実施の形態１．
図１は、実施の形態１に係る空気調和機の構成を表わす図である。Hereinafter, embodiments will be described with reference to the drawings.
Embodiment 1.
FIG. 1 is a diagram showing a configuration of an air conditioner according to the first embodiment.

図１に示すように、空気調和機は、室外機５０と、室内機５１とを備える。
室外機５０は、圧縮機１と、四方弁２と、室外熱交換器３と、膨張弁４と、室外送風機６と、外気温度センサ１１と、吐出温度センサ２３と、吐出圧力センサ２４と、吸入圧力センサ２２と、吸入温度センサ２１と、制御装置６０とを備える。As shown in FIG. 1, the air conditioner includes an outdoor unit 50 and an indoor unit 51.
The outdoor unit 50 includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, an expansion valve 4, an outdoor blower 6, an outside air temperature sensor 11, a discharge temperature sensor 23, and a discharge pressure sensor 24. It includes a suction pressure sensor 22, a suction temperature sensor 21, and a control device 60.

圧縮機１は、吸入した冷媒を圧縮して吐出する。
室外熱交換器３は、冷房運転時には、凝縮器として機能する。室外熱交換器３は、暖房運転時には、蒸発器として機能する。The compressor 1 compresses and discharges the sucked refrigerant.
The outdoor heat exchanger 3 functions as a condenser during the cooling operation. The outdoor heat exchanger 3 functions as an evaporator during the heating operation.

膨張弁４は、冷媒を膨張させる。膨張弁４は、電子膨張弁であって、開度（開口面積）をゼロ（全閉）から全開まで数段階で変化させることができる。 The expansion valve 4 expands the refrigerant. The expansion valve 4 is an electronic expansion valve, and the opening degree (opening area) can be changed in several steps from zero (fully closed) to fully open.

室外送風機６は、室外熱交換器３に室外空気（外気）を送る。
外気温度センサ１１は、室外熱交換器３の外気吸込側に室外機５０の筐体から数ｃｍ離して設置される。外気温度センサ１１は、外気温度ＴＯを計測する。The outdoor blower 6 sends outdoor air (outside air) to the outdoor heat exchanger 3.
The outside air temperature sensor 11 is installed on the outside air suction side of the outdoor heat exchanger 3 at a distance of several cm from the housing of the outdoor unit 50. The outside air temperature sensor 11 measures the outside air temperature TO.

吐出温度センサ２３は、圧縮機１から吐出される冷媒の吐出温度ＴＤ（以下、圧縮機１の吐出温度という）を検出する。 The discharge temperature sensor 23 detects the discharge temperature TD of the refrigerant discharged from the compressor 1 (hereinafter referred to as the discharge temperature of the compressor 1).

吐出圧力センサ２４は、圧縮機１から吐出される冷媒の吐出圧力ＰＤ（以下、圧縮機１の吐出圧力という）を検出する。この圧力は、冷媒回路７０における冷媒の最大圧力である。 The discharge pressure sensor 24 detects the discharge pressure PD of the refrigerant discharged from the compressor 1 (hereinafter referred to as the discharge pressure of the compressor 1). This pressure is the maximum pressure of the refrigerant in the refrigerant circuit 70.

吸入圧力センサ２２は、圧縮機１に吸入される冷媒の吸入圧力ＰＳ（以下、圧縮機１の吸入圧力という）を検出する。この圧力は、冷媒回路７０における冷媒の最小圧力である。 The suction pressure sensor 22 detects the suction pressure PS of the refrigerant sucked into the compressor 1 (hereinafter referred to as the suction pressure of the compressor 1). This pressure is the minimum pressure of the refrigerant in the refrigerant circuit 70.

吸入温度センサ２１は、圧縮機１に吸入される冷媒の吸入温度ＴＳ（以下、圧縮機１の吸入温度という）を検出する。 The suction temperature sensor 21 detects the suction temperature TS (hereinafter referred to as the suction temperature of the compressor 1) of the refrigerant sucked into the compressor 1.

室外熱交換器用温度センサ３５は、暖房運転時に室外熱交換器３内の冷媒の蒸発温度ＴＥを測定する。室外熱交換器用温度センサ３５は、冷房運転時に室外熱交換器３内の冷媒の凝縮温度を測定する。 The outdoor heat exchanger temperature sensor 35 measures the evaporation temperature TE of the refrigerant in the outdoor heat exchanger 3 during the heating operation. The outdoor heat exchanger temperature sensor 35 measures the condensation temperature of the refrigerant in the outdoor heat exchanger 3 during the cooling operation.

室内機５１は、室内熱交換器５と、室内送風機７とを備える。
室内熱交換器５は、冷房運転時には、蒸発器として機能する。室内熱交換器５は、暖房運転時には、凝縮器として機能する。The indoor unit 51 includes an indoor heat exchanger 5 and an indoor blower 7.
The indoor heat exchanger 5 functions as an evaporator during the cooling operation. The indoor heat exchanger 5 functions as a condenser during the heating operation.

室内送風機７は、室内熱交換器５に室内空気を送る。
室内熱交換器用温度センサ２５は、暖房運転時に室内熱交換器５内の冷媒の凝縮温度ＴＣを測定する。室内熱交換器用温度センサ２５は、冷房運転時に室内熱交換器５内の冷媒の蒸発温度を測定する。The indoor blower 7 sends indoor air to the indoor heat exchanger 5.
The temperature sensor 25 for the indoor heat exchanger measures the condensation temperature TC of the refrigerant in the indoor heat exchanger 5 during the heating operation. The temperature sensor 25 for the indoor heat exchanger measures the evaporation temperature of the refrigerant in the indoor heat exchanger 5 during the cooling operation.

冷媒回路７０は、圧縮機１、四方弁２、室外熱交換器３、膨張弁４、および室内熱交換器５を含む。 The refrigerant circuit 70 includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, an expansion valve 4, and an indoor heat exchanger 5.

四方弁２は、ポートａ、ｂ、ｃ、ｄを有する四方弁である。
ポートａと圧縮機１の吐出側とが配管Ｐ１で接続される。ポートｂと室外熱交換器３とが配管Ｐ２で接続される。ポートｃと圧縮機１の吸入側が配管Ｐ３で接続される。ポートｄと室内熱交換器５とが配管Ｐ４で接続される。室内熱交換器５と膨張弁４とが配管Ｐ５で接続される。膨張弁４と室外熱交換器３とが配管Ｐ６で接続される。The four-way valve 2 is a four-way valve having ports a, b, c, and d.
The port a and the discharge side of the compressor 1 are connected by a pipe P1. The port b and the outdoor heat exchanger 3 are connected by a pipe P2. The port c and the suction side of the compressor 1 are connected by a pipe P3. The port d and the indoor heat exchanger 5 are connected by a pipe P4. The indoor heat exchanger 5 and the expansion valve 4 are connected by a pipe P5. The expansion valve 4 and the outdoor heat exchanger 3 are connected by a pipe P6.

図２は、制御装置６０と、制御装置６０と接続される構成要素を表わす図である。
制御装置６０は、外気温度センサ１１から外気温度を表わす信号を受ける。制御装置６０は、吐出温度センサ２３から検出された吐出温度を表わす信号を受ける。制御装置６０は、吐出圧力センサ２４から検出された吐出圧力を表わす信号を受ける。制御装置６０は、吸入圧力センサ２２から検出された吸入圧力を表わす信号を受ける。制御装置６０は、吸入温度センサ２１から検出された吸入温度を表わす信号を受ける。制御装置６０は、室内熱交換器用温度センサ２５から検出された室内熱交換器５の温度を表わす信号を受ける。FIG. 2 is a diagram showing a control device 60 and components connected to the control device 60.
The control device 60 receives a signal indicating the outside air temperature from the outside air temperature sensor 11. The control device 60 receives a signal representing the discharge temperature detected from the discharge temperature sensor 23. The control device 60 receives a signal representing the discharge pressure detected from the discharge pressure sensor 24. The control device 60 receives a signal indicating the suction pressure detected from the suction pressure sensor 22. The control device 60 receives a signal indicating the suction temperature detected from the suction temperature sensor 21. The control device 60 receives a signal indicating the temperature of the indoor heat exchanger 5 detected from the indoor heat exchanger temperature sensor 25.

制御装置６０は、四方弁２に切替を指示する信号を送る。制御装置６０は、圧縮機１に起動、停止、または回転数を指示する信号を送る。制御装置６０は、室外送風機６に起動または停止を指示する信号を送る。制御装置６０は、室内送風機７に起動または停止を指示する信号を送る。制御装置６０は、膨張弁４の開度を制御する信号を送る。 The control device 60 sends a signal instructing switching to the four-way valve 2. The control device 60 sends a signal indicating start, stop, or rotation speed to the compressor 1. The control device 60 sends a signal instructing the outdoor blower 6 to start or stop. The control device 60 sends a signal instructing the indoor blower 7 to start or stop. The control device 60 sends a signal for controlling the opening degree of the expansion valve 4.

制御装置６０は、処理回路によって構成される。処理回路が専用のハードウエアの場合、処理回路は、たとえば、単一回路、複合回路、プログラム化したプロセッサ、ＡＳＩＣ（Application Specific Integrated Circuit）、ＦＰＧＡ（Field Programmable Gate Array）、またはこれらを組み合わせたものとすることができる。処理回路がＣＰＵの場合、制御装置６０の機能は、ソフトウエア、ファームウエア、またはソフトウエアとファームウエアとの組み合わせによって実現される。ソフトウエアおよびファームウエアは、プログラムとして記述され、メモリに格納される。処理回路は、メモリに記憶されたプログラムを実行することによって、制御装置６０の機能を実現する。ここで、メモリとは、ＲＡＭ、ＲＯＭ、フラッシュメモリ、ＥＰＲＯＭ、ＥＥＰＲＯＭなどの不揮発性または揮発性の半導体メモリ、または磁気ディスク、フレキシブルディスク、光ディスク、コンパンクトディスク、ミニディスク、ＤＶＤなどが該当する。なお、制御装置６０の各機能について、一部を専用のハードウエアで実現し、一部をソフトウエアまたはファームウエアで実現するようにしてもよい。 The control device 60 is composed of a processing circuit. When the processing circuit is dedicated hardware, the processing circuit is, for example, a single circuit, a composite circuit, a programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. Can be. When the processing circuit is a CPU, the function of the control device 60 is realized by software, firmware, or a combination of software and firmware. Software and firmware are written as programs and stored in memory. The processing circuit realizes the function of the control device 60 by executing the program stored in the memory. Here, the memory corresponds to a non-volatile or volatile semiconductor memory such as RAM, ROM, flash memory, EPROM, EEPROM, or a magnetic disk, flexible disk, optical disk, compact disk, mini disk, DVD, or the like. It should be noted that some of the functions of the control device 60 may be realized by dedicated hardware, and some may be realized by software or firmware.

まず、冷媒回路７０の冷房運転時の動作について説明する。
図３は、冷房運転時の冷媒回路７０内の冷媒の流れを表わす図である。First, the operation of the refrigerant circuit 70 during the cooling operation will be described.
FIG. 3 is a diagram showing the flow of the refrigerant in the refrigerant circuit 70 during the cooling operation.

制御装置６０は、冷媒回路７０の冷房運転時には、四方弁２を第１の状態とする。四方弁２は、第１の状態では、ポートａとポートｂとが連通し、ポートｃとポートｄとが連通する。これにより、室内熱交換器５から出力された冷媒が圧縮機１に流入し、圧縮機１から出力された冷媒が室外熱交換器３に流入する。制御装置６０は、圧縮機１の周波数と膨張弁４の開度を冷房運転に適した値に設定し、圧縮機１を起動する。これによって、冷媒回路７０は以下のように動作する。 The control device 60 sets the four-way valve 2 in the first state during the cooling operation of the refrigerant circuit 70. In the first state of the four-way valve 2, the port a and the port b communicate with each other, and the port c and the port d communicate with each other. As a result, the refrigerant output from the indoor heat exchanger 5 flows into the compressor 1, and the refrigerant output from the compressor 1 flows into the outdoor heat exchanger 3. The control device 60 sets the frequency of the compressor 1 and the opening degree of the expansion valve 4 to values suitable for the cooling operation, and starts the compressor 1. As a result, the refrigerant circuit 70 operates as follows.

圧縮機１において高温高圧にされた蒸気冷媒は、四方弁２を通過し、室外熱交換器３に流入する。室外熱交換器３は、冷房運転時には、昇圧された冷媒を冷却する凝縮器として機能する。室外送風機６によって室外熱交換器３に送られた室外空気に対して、高温高圧の蒸気冷媒は、放熱することによって凝縮し、高圧の液冷媒となる。 The high-temperature and high-pressure steam refrigerant in the compressor 1 passes through the four-way valve 2 and flows into the outdoor heat exchanger 3. The outdoor heat exchanger 3 functions as a condenser for cooling the boosted refrigerant during the cooling operation. The high-temperature and high-pressure steam refrigerant condenses by radiating heat with respect to the outdoor air sent to the outdoor heat exchanger 3 by the outdoor blower 6, and becomes a high-pressure liquid refrigerant.

その後、この高圧の液冷媒は、膨張弁４を通過することによって、減圧膨張して低温低圧の気液二相冷媒となり、室内熱交換器５に流入する。室内熱交換器５は、冷房運転時には、減圧膨張された冷媒を吸熱する蒸発器として機能する。室内送風機７によって室内熱交換器５に送られた室内空気から、低温低圧の気液二相冷媒が吸熱することによって蒸発し、低圧の蒸気冷媒となる。その後、低圧の蒸気冷媒は、四方弁２を経由して、圧縮機１に吸入される。 After that, the high-pressure liquid refrigerant passes through the expansion valve 4 and expands under reduced pressure to become a low-temperature low-pressure gas-liquid two-phase refrigerant, which flows into the indoor heat exchanger 5. The indoor heat exchanger 5 functions as an evaporator that absorbs heat of the refrigerant expanded under reduced pressure during the cooling operation. The low-temperature low-pressure gas-liquid two-phase refrigerant evaporates by absorbing heat from the indoor air sent to the indoor heat exchanger 5 by the indoor blower 7, and becomes a low-pressure steam refrigerant. After that, the low-pressure steam refrigerant is sucked into the compressor 1 via the four-way valve 2.

以降、同様の過程で、冷媒が冷媒回路７０内を圧縮機１、室外熱交換器３、膨張弁４、室内熱交換器５の順に循環する。 After that, in the same process, the refrigerant circulates in the refrigerant circuit 70 in the order of the compressor 1, the outdoor heat exchanger 3, the expansion valve 4, and the indoor heat exchanger 5.

次に、冷媒回路７０の暖房運転時の動作について説明する。
図４は、暖房運転時の冷媒回路７０内の冷媒の流れを表わす図である。Next, the operation of the refrigerant circuit 70 during the heating operation will be described.
FIG. 4 is a diagram showing the flow of the refrigerant in the refrigerant circuit 70 during the heating operation.

制御装置６０は、冷媒回路７０の暖房運転時には、四方弁２を第２の状態とする。四方弁２は、第２の状態では、ポートａとポートｄとが連通し、ポートｂとポートｃとが連通する。これにより、四方弁２が第２の状態のときには、室外熱交換器３から出力された冷媒が圧縮機１に流入し、圧縮機１から出力された冷媒が室内熱交換器５に流入する。 The control device 60 sets the four-way valve 2 in the second state during the heating operation of the refrigerant circuit 70. In the second state of the four-way valve 2, the port a and the port d communicate with each other, and the port b and the port c communicate with each other. As a result, when the four-way valve 2 is in the second state, the refrigerant output from the outdoor heat exchanger 3 flows into the compressor 1, and the refrigerant output from the compressor 1 flows into the indoor heat exchanger 5.

制御装置６０は、圧縮機１の周波数と膨張弁４の開度を暖房運転に適した値に設定し、圧縮機１を起動する。これによって、冷媒回路７０は以下のように動作する。 The control device 60 sets the frequency of the compressor 1 and the opening degree of the expansion valve 4 to values suitable for the heating operation, and starts the compressor 1. As a result, the refrigerant circuit 70 operates as follows.

圧縮機１において高温高圧にされた蒸気冷媒は、四方弁２を通過し、室内熱交換器５に流入する。室内熱交換器５は、暖房運転時には、昇圧された冷媒を冷却する凝縮器として機能する。室内送風機７によって室内熱交換器５に送られた室内空気に対して、高温高圧の蒸気冷媒は、放熱することによって凝縮し、高圧の液冷媒となる。 The high-temperature and high-pressure steam refrigerant in the compressor 1 passes through the four-way valve 2 and flows into the indoor heat exchanger 5. The indoor heat exchanger 5 functions as a condenser for cooling the boosted refrigerant during the heating operation. The high-temperature and high-pressure steam refrigerant condenses by dissipating heat to the indoor air sent to the indoor heat exchanger 5 by the indoor blower 7, and becomes a high-pressure liquid refrigerant.

その後、この高圧の液冷媒は、膨張弁４を通過することによって、減圧膨張して低温低圧の気液二相冷媒となり、室外熱交換器３に流入する。室外熱交換器３は、暖房運転時には、減圧膨張された冷媒を吸熱する蒸発器として機能する。室外送風機６によって室外熱交換器３に送られた室外空気から、低温低圧の気液二相冷媒が吸熱することによって蒸発し、低圧の蒸気冷媒となる。その後、低圧の蒸気冷媒は、四方弁２を経由して、圧縮機１に吸入される。 After that, the high-pressure liquid refrigerant passes through the expansion valve 4 and expands under reduced pressure to become a low-temperature low-pressure gas-liquid two-phase refrigerant, which flows into the outdoor heat exchanger 3. The outdoor heat exchanger 3 functions as an evaporator that absorbs heat of the refrigerant expanded under reduced pressure during the heating operation. The low-temperature low-pressure gas-liquid two-phase refrigerant evaporates by absorbing heat from the outdoor air sent to the outdoor heat exchanger 3 by the outdoor blower 6, and becomes a low-pressure steam refrigerant. After that, the low-pressure steam refrigerant is sucked into the compressor 1 via the four-way valve 2.

以降、同様の過程で、冷媒が冷媒回路７０内を圧縮機１、室内熱交換器５、膨張弁４、室外熱交換器３の順に循環する。 After that, in the same process, the refrigerant circulates in the refrigerant circuit 70 in the order of the compressor 1, the indoor heat exchanger 5, the expansion valve 4, and the outdoor heat exchanger 3.

暖房運転時において、制御装置６０は、吸入温度ＴＳと、吸入圧力ＰＳとに基づいて、吸入過熱度ＳＨｓを算出することができる。また、暖房運転時において、制御装置６０は、吸入温度ＴＳと、室外熱交換器３内の冷媒の蒸発温度ＴＥとに基づいて、吸入過熱度ＳＨｓを算出することができる。 During the heating operation, the control device 60 can calculate the suction superheat degree SHs based on the suction temperature TS and the suction pressure PS. Further, during the heating operation, the control device 60 can calculate the suction superheat degree SHs based on the suction temperature TS and the evaporation temperature TE of the refrigerant in the outdoor heat exchanger 3.

暖房運転時において、制御装置６０は、吐出温度ＴＤと、吐出圧力Ｐｄとに基づいて、吐出過熱度ＳＨｄを算出することができる。また、暖房運転時において、制御装置６０は、吐出温度ＴＤと、室内熱交換器４内の冷媒の凝縮温度ＴＣとに基づいて、吐出過熱度ＳＨｄを算出することができる。 During the heating operation, the control device 60 can calculate the discharge superheat degree SHd based on the discharge temperature TD and the discharge pressure Pd. Further, during the heating operation, the control device 60 can calculate the discharge superheat degree SHd based on the discharge temperature TD and the condensation temperature TC of the refrigerant in the indoor heat exchanger 4.

制御装置６０は、外気温度ＴＯに基づいて、圧縮機１の周波数、および室外送風機６のファン回転数などを制御する。 The control device 60 controls the frequency of the compressor 1, the fan rotation speed of the outdoor blower 6, and the like based on the outside air temperature TO.

次に、本実施の形態の空気調和機で使用する冷媒について説明する。
地球温暖化への影響から地球温暖化係数の小さい冷媒への転換が求められている。このため、空気調和機においてＲ４１０Ａ(GWP2088)、Ｒ３２(GWP675)などのＨＦＣ冷媒からＲ２９０（GWP4)、Ｒ１２７０などのＨＣ系冷媒への転換が期待されている。Next, the refrigerant used in the air conditioner of the present embodiment will be described.
Due to the impact on global warming, there is a need to switch to refrigerants with a smaller global warming potential. Therefore, it is expected that the air conditioner will switch from HFC refrigerants such as R410A (GWP2088) and R32 (GWP675) to HC-based refrigerants such as R290 (GWP4) and R1270.

たとえば、Ｒ２９０はＲ３２に比べて、１．２倍の凝縮潜熱有し、かつ吸入過熱度ＳＨｓの増加に対する凝縮器の出入口エンタルピ差を示す冷凍効果も大きい。したがって、吸入過熱度ＳＨｓが同一のときに、ある能力に必要な冷媒循環量は、Ｒ２９０は、Ｒ３２に比べて０．８倍でよいことになる。その結果、Ｒ２９０を用いたときには、Ｒ３２を用いるときよりも、圧縮機１の理論仕事が小さくなるため、理論ＣＯＰが高くなる。 For example, R290 has 1.2 times the latent heat of condensation as compared with R32, and has a large freezing effect showing a difference in enthalpy of entrance and exit of the condenser with respect to an increase in suction superheat degree SHs. Therefore, when the suction superheat degree SHs is the same, the amount of refrigerant circulation required for a certain capacity may be 0.8 times that of R32 in R290. As a result, when R290 is used, the theoretical work of the compressor 1 is smaller than when R32 is used, so that the theoretical COP is higher.

図５は、吸入過熱度ＳＨｓと理論ＣＯＰとの関係を表わす図である。
図５に示すように、吸入過熱度ＳＨｓが増加すると、Ｒ３２およびＲ４１０Ａなどのフロン系冷媒の理論ＣＯＰは低下するが、Ｒ２９０の理論ＣＯＰは増加する。これは、吸入過熱度ＳＨｓが増加するときに、Ｒ２９０はフロン系冷媒に比べて、冷媒循環量の低下率以上に冷凍効果が増加するためである。FIG. 5 is a diagram showing the relationship between the inhalation superheat degree SHs and the theoretical COP.
As shown in FIG. 5, when the suction superheat degree SHs increases, the theoretical COP of Freon-based refrigerants such as R32 and R410A decreases, but the theoretical COP of R290 increases. This is because when the suction superheat degree SHs increases, the refrigerating effect of R290 increases more than the rate of decrease in the amount of refrigerant circulation as compared with the fluorocarbon-based refrigerant.

したがって、本実施の形態では、冷媒回路７０内を循環する冷媒は、低ＧＷＰである可燃性のＨＣ系自然冷媒であるＲ２９０およびＲ１２７０のうち少なくとも一方を含む。言い換えると、冷媒回路７０内に流れる冷媒は、Ｒ２９０単独、Ｒ１２７０単独、またはこれらのうち少なくとも１つを主成分とした混合冷媒である。 Therefore, in the present embodiment, the refrigerant circulating in the refrigerant circuit 70 includes at least one of R290 and R1270, which are flammable HC-based natural refrigerants having a low GWP. In other words, the refrigerant flowing in the refrigerant circuit 70 is R290 alone, R1270 alone, or a mixed refrigerant containing at least one of these as a main component.

従来のＲ３２を用いた空気調和機では、Ｒ３２の特性から、圧縮機１の吐出温度の上昇による潤滑油およびモータの劣化が起こり易い。このため、従来のＲ３２を用いた空気調和機は、圧縮機１の吸入過熱度ＳＨｓを小さくし、吐出温度ＴＤの制御によって、吐出温度ＴＤの上昇を抑制しながら動作している。地球温暖化係数の小さいＲ２９０を用いて、Ｒ３２と同様の制御を行うと、吐出過熱度ＳＨｄが過大になり、吸入温度ＴＳおよび吸入過熱度ＳＨｓが過小になるため、ＣＯＰが低下するという問題がある。つまり、Ｒ２９０は、Ｒ３２よりも理論ＣＯＰは高いが、従来の制御では、Ｒ２９０を用いた場合、Ｒ３２を用いた場合と同等以上のＣＯＰを得ることが難しい。 In the conventional air conditioner using R32, deterioration of the lubricating oil and the motor is likely to occur due to an increase in the discharge temperature of the compressor 1 due to the characteristics of R32. Therefore, the conventional air conditioner using R32 operates while suppressing the increase in the discharge temperature TD by reducing the suction superheat degree SHs of the compressor 1 and controlling the discharge temperature TD. If the same control as R32 is performed using R290 having a small global warming potential, the discharge superheat degree SHd becomes excessive, and the suction temperature TS and the suction superheat degree SHs become too small, so that there is a problem that the COP decreases. be. That is, although the theoretical COP of R290 is higher than that of R32, it is difficult to obtain a COP equal to or higher than that of R32 when R290 is used by conventional control.

従来の炭化水素冷媒用の潤滑油として、パラフィン系炭化水素、ナフテン系炭化水素、アルキルベンゼン単体、またはこれらの混合油が用いられるが、相溶性が高いため、安全性確保の観点から冷媒充填量を規定(IEC 60335-2-40)されている強燃性のＲ２９０、Ｒ１２７０冷媒には適さない。さらに、これらの潤滑油は、粘度が低いため高圧シェルを用いた一般的な空気調和機には適さない。 Paraffinic hydrocarbons, naphthenic hydrocarbons, alkylbenzenes alone, or a mixture of these are used as lubricating oils for conventional hydrocarbon refrigerants, but since they are highly compatible, the amount of refrigerant charged should be adjusted from the viewpoint of ensuring safety. Not suitable for the highly flammable R290 and R1270 refrigerants specified (IEC 60335-2-40). Furthermore, these lubricating oils have low viscosities and are not suitable for general air conditioners using high pressure shells.

本実施の形態では、圧縮機１の潤滑油として、エーテル結合を有するポリアルキレングリコール系のＰＡＧ（Poly-Alkylene-Glycol）、ポリビニルエーテル系のＰＶＥ（Poly-vinyl-Ether）、エステル結合を有するポリオールエステル（Poly-Ol-Ester）系のＰＯＥ等の冷媒に比べ密度の高い油を使用する。冷媒として、Ｒ２９０を使用する場合には、ＰＡＧがＲ２９０との相溶性が低いため、ＰＡＧをＲ２９０用の潤滑油として使用するのが好ましい。 In the present embodiment, as the lubricating oil of the compressor 1, a polyalkylene glycol-based PAG (Poly-Alkylene-Glycol) having an ether bond, a polyvinyl ether-based PVE (Poly-vinyl-Ether), and a polyol having an ester bond are used. Use an oil with a higher density than a refrigerant such as POE based on ester (Poly-Ol-Ester). When R290 is used as the refrigerant, it is preferable to use PAG as a lubricating oil for R290 because PAG has low compatibility with R290.

室外機５０の機械室は、圧縮機１、四方弁２、膨張弁４が冷媒配管により接続されている。これらの機器と、外気とは板金製の前面、側面、後面パネルと仕切り板で覆われている。このため、圧縮機１の放熱による機械室内の周囲空気温度が外気温度ＴＯよりも高くなることがある。機械室内の空気による過熱、および四方弁２内における吐出温度ＴＤを介した冷媒の吸熱によって、吸入温度ＴＳが外気温度ＴＯよりも高くなることがある。 In the machine room of the outdoor unit 50, the compressor 1, the four-way valve 2, and the expansion valve 4 are connected by a refrigerant pipe. These devices and the outside air are covered with sheet metal front, side, rear panels and dividers. Therefore, the ambient air temperature in the machine room due to the heat radiation of the compressor 1 may be higher than the outside air temperature TO. The suction temperature TS may be higher than the outside air temperature TO due to overheating by the air in the machine room and endothermic heat of the refrigerant through the discharge temperature TD in the four-way valve 2.

欧州では、ルームエアコンの消費電力削減のため、ErP指令Lot10によって、所望の外気温におけるＣＯＰから求めたＳＣＯＰ(Seasonal Coefficient of Performance)によって規制されている。 In Europe, in order to reduce the power consumption of room air conditioners, it is regulated by the ErP Directive Lot10 by the SCOP (Seasonal Coefficient of Performance) obtained from the COP at the desired outside temperature.

図６は、外気温度ＴＯと規格化ＣＯＰとの関係を表わす図である。
規格化ＣＯＰは、各温度のＣＯＰの外気温度ＴＯが１２℃のときのＣＯＰに対する比率を表す。FIG. 6 is a diagram showing the relationship between the outside air temperature TO and the normalized COP.
The normalized COP represents the ratio of the COP at each temperature to the COP when the outside air temperature TO is 12 ° C.

外気温度ＴＯが高くなると、建物および室内の負荷が減るため、ＣＯＰは高くなる。外気温度ＴＯが－７℃のＣＯＰ（Ａ）で、２℃のＣＯＰ（Ｂ）、７℃のＣＯＰ（Ｃ）、１２℃のＣＯＰ（Ｄ）によって、ＳＣＯＰは、以下の式で表される。 When the outside air temperature TO becomes high, the load on the building and the room decreases, so that the COP becomes high. With an outside air temperature TO of -7 ° C. COP (A), a 2 ° C. COP (B), a 7 ° C. COP (C), and a 12 ° C. COP (D), SCOP is expressed by the following equation.

SCOP=0.17×COP(A)＋0.51×COP(B)+0.23×COP(C)+0.09×COP(D)・・・(1)
外気温度ＴＯが７℃のＣＯＰ（Ｃ）と外気温度ＴＯが２℃のＣＯＰ（Ｂ）のＳＣＯＰへの寄与度が特に高い。外気温度ＴＯが７℃のＣＯＰ（Ｃ）と外気温度ＴＯが２℃のＣＯＰ（Ｂ）のＳＣＯＰへの寄与度は、７４％である。外気温度ＴＯが７℃のＣＯＰ（Ｃ）と外気温度ＴＯが２℃のＣＯＰ（Ｂ）と外気温度ＴＯが１２℃のＣＯＰ（Ｄ）のＳＣＯＰへの寄与度は、８３％である。SCOP = 0.17 x COP (A) +0.51 x COP (B) +0.23 x COP (C) +0.09 x COP (D) ・ ・ ・ (1)
The contribution of COP (C) having an outside air temperature TO of 7 ° C. and COP (B) having an outside air temperature TO of 2 ° C. to SCOP is particularly high. The contribution of COP (C) having an outside air temperature TO of 7 ° C. and COP (B) having an outside air temperature TO of 2 ° C. to SCOP is 74%. The contribution of COP (C) having an outside air temperature TO of 7 ° C., COP (B) having an outside air temperature TO of 2 ° C., and COP (D) having an outside air temperature TO of 12 ° C. to SCOP is 83%.

また、図６に示すように、外気温度ＴＯに対して、空気調和機のＣＯＰは、線形に変化する。よって、空気調和機の３つの外気温度ＴＯに対するＣＯＰが決まると、空気調機器のＳＣＯＰは概ね決定される。ただし、外気温度ＴＯが負の場合の暖房運転では、除霜運転を伴うため、理論上のＣＯＰと実際のＣＯＰとにずれが生じることがある。よって、本実施の形態では、外気温度ＴＯがＳＣＯＰを求める際の条件である外気温度ＴＯが－７℃、２℃、７℃、１２℃のうち、２℃、７℃、１２℃の３つの外気温度ＴＯについて検討する。 Further, as shown in FIG. 6, the COP of the air conditioner changes linearly with respect to the outside air temperature TO. Therefore, when the COP for the three outside air temperature TOs of the air conditioner is determined, the SCOP of the air conditioner is generally determined. However, in the heating operation when the outside air temperature TO is negative, the defrosting operation is involved, so that the theoretical COP and the actual COP may deviate from each other. Therefore, in the present embodiment, the outside air temperature TO, which is a condition for obtaining the SCOP, is -7 ° C, 2 ° C, 7 ° C, and 12 ° C, of which 2 ° C, 7 ° C, and 12 ° C. Consider the outside air temperature TO.

図７（ａ）～（ｃ）は、Ｒ２９０とＲ３２における吸入温度ＴＳと規格化ＣＯＰとの関係を表わす図である。図７（ａ）～（ｃ）には、外気温度ＴＯが２℃、７℃、１２℃において、ＳＣＯＰを定める条件である吸入過熱度ＳＨｓが０．１～２０ｄｅｇに変化するときの、吸入温度ＴＳと規格化ＣＯＰとの関係が示されている。吸入過熱度ＳＨｓが０．１ｄｅｇのときに、吸入温度ＴＳが最小となる。吸入過熱度ＳＨｓが２０ｄｅｇのときに、吸入温度ＴＳが最大となる。Ｒ３２の吸入過熱度ＳＨｓが０．１ｄｅｇのときのＣＯＰをＸとすると、規格化ＣＯＰは、（ＣＯＰ／Ｘ）×１００で表わされる。 7 (a) to 7 (c) are diagrams showing the relationship between the suction temperature TS and the normalized COP in R290 and R32. 7 (a) to 7 (c) show the suction temperature when the outside air temperature TO is 2 ° C., 7 ° C., and 12 ° C. and the suction superheat degree SHs, which is a condition for determining SCOP, changes from 0.1 to 20 deg. The relationship between TS and standardized COP is shown. When the suction superheat degree SHs is 0.1 deg, the suction temperature TS becomes the minimum. When the suction superheat degree SHs is 20 deg, the suction temperature TS becomes maximum. Assuming that the COP when the inhalation superheat degree SHs of R32 is 0.1 deg is X, the normalized COP is represented by (COP / X) × 100.

図７（ａ）～（ｃ）における水平な直線Ｌ１、Ｌ２、Ｌ３は、他の外気温度ＴＯにおいてＣＯＰがＲ３２と同等である場合に、Ｒ３２と同等のＳＣＯＰとなるためのＣＯＰの下限を示す。ここで、外気温度ＴＯが２℃、７℃において、Ｌ１、Ｌ２は９７％を表わす。外気温度ＴＯが１２℃において、Ｌ３は９３％を示す。 The horizontal straight lines L1, L2, and L3 in FIGS. 7 (a) to 7 (c) indicate the lower limit of the COP for achieving the SCOP equivalent to R32 when the COP is equivalent to R32 at another outside air temperature TO. .. Here, when the outside air temperature TO is 2 ° C. and 7 ° C., L1 and L2 represent 97%. When the outside air temperature TO is 12 ° C., L3 shows 93%.

図７（ａ）に示すように、外気温度ＴＯが２℃の時、吸入温度ＴＳを０℃～６．６℃の範囲、すなわちΔＴが－２．０℃～＋４．６℃の範囲内において、Ｒ３２を用いるよりもＲ２９０を用いた方が、空気調和器のＣＯＰが高くなる。ΔＴ＜－２℃のときには、吸入温度ＴＳが０℃よりも小さくなるため、吸入配管が着霜し、ＣＯＰが著しく低下する。 As shown in FIG. 7A, when the outside air temperature TO is 2 ° C., the suction temperature TS is in the range of 0 ° C. to 6.6 ° C., that is, ΔT is in the range of −2.0 ° C. to + 4.6 ° C. , The COP of the air conditioner is higher when R290 is used than when R32 is used. When ΔT <-2 ° C., the suction temperature TS becomes smaller than 0 ° C., so that the suction pipe is frosted and the COP is significantly lowered.

図７（ｂ）に示すように、外気温度ＴＯが７℃の時、吸入温度ＴＳを３．０℃～７．６℃の範囲、すなわちΔＴが－４．０℃～＋０．６℃の範囲内において、Ｒ３２を用いるよりもＲ２９０を用いた方が、空気調和器のＣＯＰが高くなる。ΔＴ(＝ＴＳ－ＴＯ)＞０．６℃のときには、Ｒ２９０を用いたときのＣＯＰがＲ３２を用いたときのＣＯＰよりも小さくなるため、Ｒ３２よりも理論ＣＯＰの高いＲ２９０の特性を活かした運転ができなくなる。 As shown in FIG. 7B, when the outside air temperature TO is 7 ° C., the suction temperature TS is in the range of 3.0 ° C. to 7.6 ° C., that is, ΔT is in the range of -4.0 ° C. to + 0.6 ° C. Among them, the COP of the air conditioner is higher when R290 is used than when R32 is used. When ΔT (= TS-TO)> 0.6 ° C., the COP when using R290 is smaller than the COP when using R32, so the operation utilizing the characteristics of R290, which has a higher theoretical COP than R32. Cannot be done.

図７（ｃ）に示すように、外気温度ＴＯが１２℃の時、吸入温度ＴＳを９．４℃～１３．６℃の範囲、すなわちΔＴが－２．６℃～＋１．６℃の範囲内において、Ｒ３２を用いるよりもＲ２９０を用いた方が、空気調和器のＣＯＰが高くなる。 As shown in FIG. 7 (c), when the outside air temperature TO is 12 ° C., the suction temperature TS is in the range of 9.4 ° C. to 13.6 ° C., that is, ΔT is in the range of -2.6 ° C. to + 1.6 ° C. Among them, the COP of the air conditioner is higher when R290 is used than when R32 is used.

以上のように外気温度ＴＯごとのΔTの範囲で制御することにより、Ｒ３２を用いた運転よりも高いＣＯＰで、Ｒ２９０を用いた運転が可能である。 By controlling in the range of ΔT for each outside air temperature TO as described above, it is possible to operate using R290 at a higher COP than the operation using R32.

さらに、ΔＴ(＝ＴＳ－ＴＯ)を－２．０℃～＋０．６℃の範囲にすることによって、外気温度ＴＯに依らずに、Ｒ３２を用いた運転よりも高いＣＯＰで、Ｒ２９０を用いた運転が可能となる。 Furthermore, by setting ΔT (= TS-TO) in the range of −2.0 ° C. to + 0.6 ° C., R290 was used at a higher COP than the operation using R32, regardless of the outside air temperature TO. It becomes possible to drive.

以上より、本実施の形態では、制御装置６０は、暖房運転時、吸入温度ＴＳと外気温度ＴＯの差ΔＴ（ＴＳ－ＴＯ)が範囲Ｗ（－２．０～＋０．６）内となるように、膨張弁４を制御する。これによって、冷媒にＲ２９０を用いた時に、Ｒ３２を用いた時よりも、同等以上のＳＣＯＰで空気調和機を暖房運転することができる。Ｒ２９０を例に説明したが、Ｒ２９０と沸点および動作圧などの特性が類似しているＲ１２７０でも同様の効果が得られる。 From the above, in the present embodiment, in the control device 60, the difference ΔT (TS-TO) between the suction temperature TS and the outside air temperature TO is within the range W (−2.0 to +0.6) during the heating operation. In addition, the expansion valve 4 is controlled. As a result, when R290 is used as the refrigerant, the air conditioner can be heated and operated with a SCOP equal to or higher than that when R32 is used. Although R290 has been described as an example, the same effect can be obtained with R1270 having similar characteristics such as boiling point and operating pressure to R290.

図８は、実施の形態１の空気調和機の暖房運転時の制御手順を表わすフローチャートである。 FIG. 8 is a flowchart showing a control procedure during the heating operation of the air conditioner according to the first embodiment.

ステップＳ１０１において、外気温度センサ１１が、外気温度ＴＯを検出する。制御装置６０は、外気温度センサ１１から外気温度ＴＯを表わす信号を受ける。 In step S101, the outside air temperature sensor 11 detects the outside air temperature TO . The control device 60 receives a signal representing the outside air temperature TO from the outside air temperature sensor 11 .

ステップＳ１０２において、吸入温度センサ２１は、圧縮機１の吸入温度ＴＳを検出する。制御装置６０は、吸入温度センサ２１から検出された吸入温度ＴＳを表わす信号を受ける。 In step S120, the suction temperature sensor 21 detects the suction temperature TS of the compressor 1 . The control device 60 receives a signal representing the suction temperature TS detected from the suction temperature sensor 21.

ステップＳ１０３において、制御装置６０は、温度差ΔＴ＝ＴＳ－ＴＯを算出する。
ステップＳ１０４において、温度差ΔＴが（－２．０）℃未満のときには（Ｓ１０４：ＹＥＳ）、処理がステップＳ１０５に進む。ステップＳ１０６において、温度差ΔＴが（＋０．６）℃を超えるときには（Ｓ１０６：ＹＥＳ）、処理がステップＳ１０７に進む。温度差ΔＴが（－２．０）℃以上、かつ（＋０．６）℃以下のときには（Ｓ１０４：ＮＯ、Ｓ１０６：ＮＯ）、処理が終了する。In step S103, the control device 60 calculates the temperature difference ΔT = TS-TO.
In step S104, when the temperature difference ΔT is less than (−2.0) ° C. (S104: YES), the process proceeds to step S105. In step S106, when the temperature difference ΔT exceeds (+0.6) ° C. (S106: YES), the process proceeds to step S107. When the temperature difference ΔT is (−2.0) ° C. or higher and (+0.6) ° C. or lower (S104: NO, S106: NO), the process ends.

ステップＳ１０５において、制御装置６０は、膨張弁４の開度を一定量だけ減少させる。その後、処理がステップＳ１０１に戻る。 In step S105, the control device 60 reduces the opening degree of the expansion valve 4 by a certain amount. After that, the process returns to step S101.

ステップＳ１０７において、制御装置６０は、膨張弁４の開度を一定量だけ増加させる。その後、処理がステップＳ１０１に戻る。 In step S107, the control device 60 increases the opening degree of the expansion valve 4 by a certain amount. After that, the process returns to step S101.

実施の形態２．
図７（ａ）～（ｃ）に示すように、外気温度ＴＯと吸入温度ＴＳとが等しくなるように制御すると、Ｒ３２は、冷媒の特性から外気温度ＴＯよりも高い吸入温度ＴＳにおいて、ＣＯＰが最大となるため、高いＣＯＰでの運転はできない。一方、Ｒ２９０は高いＣＯＰでの運転が可能である。Embodiment 2.
As shown in FIGS. 7A to 7C, when the outside air temperature TO and the suction temperature TS are controlled to be equal to each other, R32 has a COP at a suction temperature TS higher than the outside air temperature TO due to the characteristics of the refrigerant. Since it is the maximum, it cannot be operated at a high COP. On the other hand, the R290 can be operated at a high COP.

本実施の形態では、制御装置６０は、吸入温度ＴＳが外気温度ＴＯとが等しくなるよう膨張弁４を制御する。 In the present embodiment, the control device 60 controls the expansion valve 4 so that the suction temperature TS becomes equal to the outside air temperature TO.

図９は、実施の形態２の暖房運転時の空気調和機の制御手順を表わすフローチャートである。 FIG. 9 is a flowchart showing a control procedure of the air conditioner during the heating operation of the second embodiment.

ステップＳ２０１において、外気温度センサ１１が、外気温度ＴＯを検出する。制御装置６０は、外気温度センサ１１から外気温度ＴＯを表わす信号を受ける。 In step S201, the outside air temperature sensor 11 detects the outside air temperature TO. The control device 60 receives a signal representing the outside air temperature TO from the outside air temperature sensor 11.

ステップＳ２０２において、吸入温度センサ２１は、圧縮機１の吸入温度ＴＳを検出する。制御装置６０は、吸入温度センサ２１から検出された吸入温度ＴＳを表わす信号を受ける。 In step S202, the suction temperature sensor 21 detects the suction temperature TS of the compressor 1. The control device 60 receives a signal representing the suction temperature TS detected from the suction temperature sensor 21.

ステップＳ２０３において、制御装置６０は、温度差ΔＴ＝ＴＳ－ＴＯを算出する。
ステップＳ２０３において、吸入温度ＴＳが外気温度ＴＯ未満のときには（Ｓ２０３：ＹＥＳ）、処理がステップＳ２０４に進む。ステップＳ２０５において、吸入温度ＴＳが外気温度ＴＯを超えるときには（Ｓ２０５：ＹＥＳ）、処理がステップＳ２０６に進む。吸入温度ＴＳが外気温度ＴＯと等しいときには（Ｓ２０３：ＮＯ、Ｓ２０５：ＮＯ）、処理が終了する。In step S203, the control device 60 calculates the temperature difference ΔT = TS-TO.
In step S203, when the suction temperature TS is lower than the outside air temperature TO (S203: YES), the process proceeds to step S204. In step S205, when the suction temperature TS exceeds the outside air temperature TO (S205: YES), the process proceeds to step S206. When the suction temperature TS is equal to the outside air temperature TO (S203: NO, S205: NO), the process ends.

ステップＳ２０４において、制御装置６０は、膨張弁４の開度を一定量だけ減少させる。その後、処理がステップＳ２０１に戻る。 In step S204, the control device 60 reduces the opening degree of the expansion valve 4 by a certain amount. After that, the process returns to step S201 .

ステップＳ２０６において、制御装置６０は、膨張弁４の開度を一定量だけ増加させる。その後、処理がステップＳ２０１に戻る。 In step S206, the control device 60 increases the opening degree of the expansion valve 4 by a certain amount. After that, the process returns to step S201 .

本実施の形態によれば、外気温度ＴＯの変化に応じて、高いＣＯＰを確保しながらの運転が可能になる。制御装置６０は、外気温度ＴＯを検知しながら吸入温度ＴＳを制御するため、吸入過熱度ＳＨｓで制御を行う場合に比べて、圧縮機１に吸入される冷媒を過熱ガスにしながら制御することができる。すなわち、蒸発温度ＴＥ＜外気温度ＴＯで空気調和機は、運転されるが、本実施の形態では外気温度ＴＯ＝吸入温度ＴＳとなるように制御されるので、蒸発温度ＴＥ＜吸入温度ＴＳとなる。これによって、確実に圧縮機１に吸入される冷媒を過熱ガスにできる。その結果、圧縮機１の故障の要因となる液戻り運転を防止できるため、安定した運転が実現できる。また、吸入温度が０℃以下となる運転を回避し易くなるため、吸入配管の着霜を防止できるので、霜により熱抵抗が増大した配管内の冷媒の再凝縮を抑制できる。 According to this embodiment, it is possible to operate while ensuring a high COP in response to a change in the outside air temperature TO. Since the control device 60 controls the suction temperature TS while detecting the outside air temperature TO, it is possible to control the refrigerant sucked into the compressor 1 while using the superheated gas as compared with the case where the control is performed by the suction superheat degree SHs. can. That is, the air conditioner is operated with the evaporation temperature TE <outside air temperature TO, but in the present embodiment, it is controlled so that the outside air temperature TO = suction temperature TS, so that the evaporation temperature TE <suction temperature TS. .. As a result, the refrigerant surely sucked into the compressor 1 can be made into a superheated gas. As a result, the liquid return operation that causes the failure of the compressor 1 can be prevented, so that stable operation can be realized. Further, since it becomes easy to avoid the operation in which the suction temperature becomes 0 ° C. or lower, frost formation in the suction pipe can be prevented, so that recondensation of the refrigerant in the pipe whose thermal resistance has increased due to frost can be suppressed.

実施の形態３．
図１０（ａ）～（ｃ）は、Ｒ２９０とＲ３２における吐出過熱度ＳＨｄと規格化ＣＯＰとの関係を表わす図である。Embodiment 3.
10 (a) to 10 (c) are diagrams showing the relationship between the discharge superheat degree SHd and the normalized COP in R290 and R32.

図１０（ａ）～（ｃ）には、外気温度ＴＯが２℃、７℃、１２℃において、ＳＣＯＰを定める条件である吸入過熱度ＳＨｓが０．１～２０ｄｅｇに変化するときの、吐出過熱度ＳＨｄと規格化ＣＯＰとの関係が示されている。吸入過熱度ＳＨｓが０．１ｄｅｇのときに、吐出過熱度ＳＨｄが最小となる。吸入過熱度ＳＨｓが２０ｄｅｇのときに、吐出過熱度ＳＨｄが最大となる。Ｒ３２の吸入過熱度ＳＨｓが０．１ｄｅｇのときのＣＯＰをＸとすると、規格化ＣＯＰは、（ＣＯＰ／Ｘ）×１００で表わされる。 10 (a) to 10 (c) show the discharge superheat when the intake superheat degree SHs, which is a condition for determining SCOP, changes from 0.1 to 20 deg when the outside air temperature TO is 2 ° C, 7 ° C, and 12 ° C. The relationship between degree SHd and normalized COP is shown. When the suction superheat degree SHs is 0.1 deg, the discharge superheat degree SHd becomes the minimum. When the suction superheat degree SHs is 20 deg, the discharge superheat degree SHd becomes maximum. Assuming that the COP when the inhalation superheat degree SHs of R32 is 0.1 deg is X, the normalized COP is represented by (COP / X) × 100.

図１０（ａ）～図１０（ｃ）に示すように、各外気温度ＴＯにおいて、Ｒ３２よりもＲ２９０のＣＯＰが高くなる吐出過熱度ＳＨｄの範囲が存在する。この範囲の最大値をＵ（ＳＨｄ）とする。 As shown in FIGS. 10A to 10C, there is a range of discharge superheat degree SHd in which the COP of R290 is higher than that of R32 at each outside air temperature TO. The maximum value in this range is U (SHd).

図１０（ａ）～（ｃ）に示すように、外気温度ＴＯに対し、Ｒ３２よりもＣＯＰが高くあるＲ２９０の吐出過熱度ＳＨｄは、Ｒ３２に比べ小さくなっている。これは、Ｒ２９０とＲ３２冷媒の物性の違いによるものである。 As shown in FIGS. 10A to 10C, the discharge superheat degree SHd of R290, which has a higher COP than R32 with respect to the outside air temperature TO, is smaller than that of R32. This is due to the difference in physical properties between the R290 and R32 refrigerants.

外気温度ＴＯに対して、Ｕ（ＳＨｄ）は、以下の式で表わすことができる。
U(SHd)=-1.1559×TO+19.574・・・(2)
一方、外気温度ＴＯに対して、圧縮機１が液バック運転しない吐出過熱度ＳＨｄの下限をＬ（ＳＨｄ）とすると、Ｌ（ＳＨｄ）は、以下の式で表わすことができる。With respect to the outside air temperature TO, U (SHd) can be expressed by the following equation.
U (SHd) =-1.1559 × TO + 19.574 ・ ・ ・ (2)
On the other hand, assuming that the lower limit of the discharge superheat degree SHd in which the compressor 1 does not perform the liquid back operation with respect to the outside air temperature TO is L (SHd), L (SHd) can be expressed by the following equation.

L(SHd)=-0.4526×TO+9.5755・・・(3)
図１１は、Ｒ３２のＣＯＰよりもＲ２９０のＣＯＰが高くなり、かつ圧縮機１が液バック運転しない吐出過熱度ＳＨｄの範囲を表わす図である。L (SHd) =-0.4526 × TO +9.5755 ・ ・ ・ (3)
FIG. 11 is a diagram showing a range of discharge superheat degree SHd in which the COP of R290 is higher than the COP of R32 and the compressor 1 does not perform the liquid back operation.

図１１において、直線Ｒ１は、式（２）で表される。直線Ｒ２は、式（３）で表される。直線Ｒ１と直線Ｒ２の間の範囲（直線Ｒ１およびＲ２を含む）において、Ｒ３２のＣＯＰよりもＲ２９０のＣＯＰが高くなり、かつ圧縮機１が液バック運転しない。図１１において、外気温度ＴＯが高くなるほど、空調負荷が小さくなるため、Ｒ２９０を用いたときに、Ｒ３２を用いたときよりも高いＣＯＰで運転可能な吐出過熱度ＳＨｄの範囲は小さくなる。 In FIG. 11, the straight line R1 is represented by the equation (2). The straight line R2 is represented by the equation (3). In the range between the straight lines R1 and R2 (including the straight lines R1 and R2), the COP of R290 is higher than the COP of R32, and the compressor 1 does not operate in liquid back. In FIG. 11, the higher the outside air temperature TO, the smaller the air conditioning load. Therefore, when R290 is used, the range of the discharge superheat degree SHd that can be operated at a higher COP than when R32 is used becomes smaller.

本実施の形態では、制御装置６０は、外気温度ＴＯに基づいて、吐出過熱度ＳＨｄが式（３）で表されるＬ（ＳＨｄ）以上、かつ式（２）で表されるＵ（ＳＨｄ）以下となるように、膨張弁４の開度を制御する。 In the present embodiment, the control device 60 has a discharge superheat degree SHd equal to or higher than L (SHd) represented by the formula (3) and U (SHd) represented by the formula (2) based on the outside air temperature TO. The opening degree of the expansion valve 4 is controlled so as to be as follows.

図１２は、実施の形態３の暖房運転時の空気調和機の制御手順を表わすフローチャートである。 FIG. 12 is a flowchart showing a control procedure of the air conditioner during the heating operation of the third embodiment.

ステップＳ３００において、外気温度センサ１１が、外気温度ＴＯを検出する。制御装置６０は、外気温度センサ１１から外気温度ＴＯを表わす信号を受ける。 In step S300, the outside air temperature sensor 11 detects the outside air temperature TO. The control device 60 receives a signal representing the outside air temperature TO from the outside air temperature sensor 11.

ステップＳ３０１において、吐出温度センサ２３が、圧縮機１の吐出温度ＴＤを検出する。制御装置６０は、吐出温度センサ２３から吐出温度ＴＤを表わす信号を受ける。 In step S301, the discharge temperature sensor 23 detects the discharge temperature TD of the compressor 1 . The control device 60 receives a signal representing the discharge temperature TD from the discharge temperature sensor 23 .

ステップＳ３０２において、室内熱交換器用温度センサ２５が、室内熱交換器５内の冷媒の凝縮温度ＴＣを検出する。制御装置６０は、室内熱交換器用温度センサ２５から冷媒の凝縮温度ＴＣを表わす信号を受ける。 In step S302, the indoor heat exchanger temperature sensor 25 detects the condensation temperature TC of the refrigerant in the indoor heat exchanger 5. The control device 60 receives a signal indicating the condensation temperature TC of the refrigerant from the temperature sensor 25 for the indoor heat exchanger.

ステップＳ３０３において、制御装置６０は、ＴＤからＴＣを減算することによって、吐出過熱度ＳＨｄ（＝ＴＤ－ＴＣ）を求める。 In step S303, the control device 60 obtains the discharge superheat degree SHd (= TD-TC) by subtracting TC from TD.

ステップＳ３０４において、制御装置６０は、式（３）によって、外気温度ＴＯからＬ（ＳＨｄ）を算出する。 In step S304, the control device 60 calculates L (SHd) from the outside air temperature TO by the equation ( 3 ).

ステップＳ３０５において、制御装置６０は、式（２）によって、外気温度ＴＯからＵ（ＳＨｄ）を算出する。 In step S305, the control device 60 calculates U ( SHd ) from the outside air temperature TO by the equation ( 2 ).

ステップＳ３０６において、吐出過熱度ＳＨｄがＬ（ＳＨｄ）未満のときには（Ｓ３０６：ＹＥＳ）、処理がステップＳ３０７に進む。ステップＳ３０８において、吐出過熱度ＳＨｄがＵ（ＳＨｄ）を超えるときには（Ｓ３０８：ＹＥＳ）、処理がステップＳ３０９に進む。吐出過熱度ＳＨｄがＬ（ＳＨｄ）以上、かつＵ（ＳＨｄ）以下のときには（Ｓ３０６：ＮＯ、Ｓ３０８：ＮＯ）、処理が終了する。 In step S306, when the discharge superheat degree SHd is less than L ( SHd ) (S306: YES), the process proceeds to step S307. In step S308, when the discharge superheat degree SHd exceeds U (SHd) (S308: YES), the process proceeds to step S309. When the discharge superheat degree SHd is L (SHd) or more and U ( SHd ) or less (S306: NO, S308: NO), the process ends.

ステップＳ３０７において、制御装置６０は、膨張弁４の開度を一定量だけ減少させる。その後、処理がステップＳ３００に戻る。 In step S307, the control device 60 reduces the opening degree of the expansion valve 4 by a certain amount. After that, the process returns to step S300 .

ステップＳ３０９において、制御装置６０は、膨張弁４の開度を一定量だけ増加させる。その後、処理がステップＳ３００に戻る。 In step S309, the control device 60 increases the opening degree of the expansion valve 4 by a certain amount. After that, the process returns to step S300 .

本実施の形態では、Ｒ２９０を用いてもＲ３２よりも高いＣＯＰで制御可能になる。また、外気温度ＴＯの変化に対して追従性が高く、かつ細かい制御が可能になるため、従来の吐出温度の制御に比べ、より高い省エネ性を得られる。Ｒ２９０と沸点および動作圧などの特性が類似しているＲ１２７０でも同様の効果が得られる。 In this embodiment, even if R290 is used, control is possible at a higher COP than R32. Further, since the followability to the change of the outside air temperature TO is high and fine control is possible, higher energy saving can be obtained as compared with the conventional control of the discharge temperature. Similar effects can be obtained with R1270, which has similar characteristics such as boiling point and operating pressure to R290.

また、吐出過熱度ＳＨｄが上述の範囲となるように制御するときには、冷媒としてＲ２９０を用い、圧縮機１の潤滑油としてＰＡＧを用いた場合に、ＰＡＧ内に冷媒が溶解する割合を３０％以下に制御することができる。その結果、冷媒充填量を許容冷媒量以下とすることができる。Ｒ２９０と沸点および動作圧などの特性が類似しているＲ１２７０を用いても、同様の効果が得られる。 Further, when the discharge superheat degree SHd is controlled to be within the above range, when R290 is used as the refrigerant and PAG is used as the lubricating oil of the compressor 1, the ratio of the refrigerant dissolved in the PAG is 30% or less. Can be controlled to. As a result, the refrigerant filling amount can be set to be equal to or less than the allowable refrigerant amount. Similar effects can be obtained by using R1270, which has similar characteristics such as boiling point and operating pressure to R290.

（変形例）
本発明は、上記の実施形態に限定されるものではなく、たとえば、以下のような変形例も含む。(Modification example)
The present invention is not limited to the above embodiment, and includes, for example, the following modifications.

（１）膨張弁の制御
実施の形態１の図８のステップＳ１０５、Ｓ１０７において、制御装置は、膨張弁の開度を一定量だけ変化させたが、これに限定されるものではない。制御装置は、膨張弁の開度をΔＴと（－２．０℃）の差、またはΔＴと（＋０．６℃）との差の大きさに応じた量だけ変化させるものとしてもよい。 (1) Control of expansion valve In steps S105 and S107 of FIG. 8 of the first embodiment, the control device changes the opening degree of the expansion valve by a certain amount, but the control device is not limited thereto. The control device may change the opening degree of the expansion valve by an amount corresponding to the magnitude of the difference between ΔT and (−2.0 ° C. ) or the difference between ΔT and (+ 0.6 ° C. ).

同様に、実施の形態２の図９のステップＳ２０４、Ｓ２０６において、制御装置は、膨張弁の開度を一定量だけ変化させたが、これに限定されるものではない。制御装置は、膨張弁の開度をＴＳとＴＯとの差の大きさに応じた量だけ変化させるものとしてもよい。 Similarly, in steps S204 and S206 of FIG. 9 of the second embodiment, the control device changes the opening degree of the expansion valve by a certain amount, but is not limited thereto. The control device may change the opening degree of the expansion valve by an amount corresponding to the magnitude of the difference between TS and TO.

同様に、実施の形態３の図１２のステップＳ３０７、Ｓ３０９において、制御装置は、膨張弁の開度を一定量だけ変化させたが、これに限定されるものではない。制御装置は、膨張弁の開度をＳＨｄとＬ（ＳＨｄ）との差、またはＳＨｄとＵ（ＳＨｄ）との差の大きさに応じた量だけ変化させるものとしてもよい。 Similarly, in steps S307 and S309 of FIG. 12 of the third embodiment, the control device changes the opening degree of the expansion valve by a certain amount, but is not limited thereto. The control device may change the opening degree of the expansion valve by an amount corresponding to the difference between SHd and L (SHd) or the difference between SHd and U (SHd).

（２）外気温度に応じた制御
制御装置は、外気温度ＴＯが２℃の時、ΔＴ（＝吸入温度ＴＳ－外気温度ＴＯ）が範囲Ｗ（－２．０℃～＋４．６℃）内となるように、膨張弁を制御するものとしてもよい。すなわち、制御装置は、外気温度ＴＯが２℃のときに、ΔＴが（－２．０℃）未満の場合に、膨張弁の開度を一定量だけ減少させ、ΔＴが（＋４．６℃）を超えるときに、膨張弁の開度を一定量だけ増加させるものとしてもよい。 (2) Control according to the outside air temperature When the outside air temperature TO is 2 ° C, ΔT (= suction temperature TS-outside air temperature TO) is within the range W (-2.0 ° C to + 4.6 ° C). The expansion valve may be controlled so as to be. That is, when the outside air temperature TO is 2 ° C. and ΔT is less than (−2.0 ° C. ), the control device reduces the opening degree of the expansion valve by a certain amount, and ΔT is (+4.6 ° C. ). When it exceeds, the opening degree of the expansion valve may be increased by a certain amount.

制御装置は、外気温度ＴＯが７℃の時、ΔＴが範囲Ｗ（－４．０℃～＋０．６℃）内となるように、膨張弁を制御するものとしてもよい。すなわち、制御装置は、外気温度ＴＯが７℃のときに、ΔＴが（－４．０℃）未満の場合に、膨張弁の開度を一定量だけ減少させ、ΔＴが（＋０．６℃）を超えるときに、膨張弁の開度を一定量だけ増加させるものとしてもよい。 The control device may control the expansion valve so that ΔT is within the range W (-4.0 ° C to + 0.6 ° C) when the outside air temperature TO is 7 ° C. That is, when the outside air temperature TO is 7 ° C. and ΔT is less than (-4.0 ° C. ), the control device reduces the opening degree of the expansion valve by a certain amount, and ΔT is (+ 0.6 ° C. ). When it exceeds, the opening degree of the expansion valve may be increased by a certain amount.

制御装置は、外気温度ＴＯが１２℃の時、ΔＴが範囲Ｗ（－２．６℃～＋１．６℃）内となるように、膨張弁を制御するものとしてもよい。すなわち、制御装置は、外気温度ＴＯが７℃のときに、ΔＴが（－２．６℃）未満の場合に、膨張弁の開度を一定量だけ減少させ、ΔＴが（＋１．６℃）を超えるときに、膨張弁の開度を一定量だけ増加させるものとしてもよい。 The control device may control the expansion valve so that ΔT is within the range W (-2.6 ° C to + 1.6 ° C) when the outside air temperature TO is 12 ° C. That is, when the outside air temperature TO is 7 ° C. and ΔT is less than (-2.6 ° C. ), the control device reduces the opening degree of the expansion valve by a certain amount, and ΔT is (+ 1.6 ° C. ). When it exceeds, the opening degree of the expansion valve may be increased by a certain amount.

制御装置は、外気温度が２℃、７℃、または１２℃以外の時には、範囲Ｗの上限、および下限を線形補間によって求めるものとしてもよい。 When the outside air temperature is other than 2 ° C., 7 ° C., or 12 ° C., the control device may obtain the upper limit and the lower limit of the range W by linear interpolation.

今回開示された実施の形態はすべての点で例示であって制限的なものではないと考えられるべきである。本発明の範囲は上記した説明ではなくて請求の範囲によって示され、請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。 It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope of the claims.

１ 圧縮機、２ 四方弁、３ 室外熱交換器、４ 膨張弁、５ 室内熱交換器、６ 室外送風機、７ 室内送風機、１１ 外気温度センサ、２１ 吸入温度センサ、２２ 吸入圧力センサ、２３ 吐出温度センサ、２４ 吐出圧力センサ、２５ 室内熱交換器用温度センサ、３５ 室外熱交換器用温度センサ、 ５０ 室外機、５１ 室内機、６０ 制御装置、７０ 冷媒回路、Ｐ４，Ｐ５，Ｐ６ 配管。 1 Compressor, 2 4-way valve, 3 Outdoor heat exchanger, 4 Expansion valve, 5 Indoor heat exchanger, 6 Outdoor blower, 7 Indoor blower, 11 Outdoor air temperature sensor, 21 Intake temperature sensor, 22 Intake pressure sensor, 23 Discharge temperature Sensor, 24 Discharge pressure sensor, 25 Temperature sensor for indoor heat exchanger, 35 Temperature sensor for outdoor heat exchanger, 50 Outdoor unit, 51 Indoor unit, 60 Control device, 70 Refrigerator circuit, P4, P5, P6 piping.

Claims (14)

圧縮機と、凝縮器と、膨張弁と、蒸発器とを含み、冷媒を循環させるように構成された冷媒回路と、
前記圧縮機への前記冷媒の吸入温度を検出するように構成された第１のセンサと、
外気温度を検出するように構成された第２のセンサとを備え、
前記冷媒は、Ｒ２９０およびＲ１２７０のうちの少なくとも一方を含み、
暖房運転時に、前記吸入温度から前記外気温度を減算することによって得られる値が（－２．０℃）を下回ると、前記膨張弁の開度が減少し、前記値が（＋０．６℃）を超えるときに、前記膨張弁の開度が増加する、空気調和機。 A refrigerant circuit including a compressor, a condenser, an expansion valve, and an evaporator, which is configured to circulate the refrigerant.
A first sensor configured to detect the suction temperature of the refrigerant into the compressor, and
Equipped with a second sensor configured to detect outside air temperature,
The refrigerant comprises at least one of R290 and R1270.
When the value obtained by subtracting the outside air temperature from the suction temperature during the heating operation is less than (−2.0 ° C.), the opening degree of the expansion valve decreases and the value becomes (+ 0.6 ° C.). An air conditioner in which the opening degree of the expansion valve increases when the temperature exceeds. 暖房運転時に、前記値が（－２．０℃）を下回ると、前記値と（－２．０℃）との差の大きさに応じた量だけ前記膨張弁の開度が減少し、前記値が（＋０．６℃）を超えるときに、前記値と（＋０．６℃）との差の大きさに応じた量だけ前記膨張弁の開度が増加する、請求項１記載の空気調和機。When the value falls below (-2.0 ° C.) during the heating operation, the opening degree of the expansion valve decreases by an amount corresponding to the magnitude of the difference between the value and (-2.0 ° C.), and the above-mentioned The air conditioning according to claim 1, wherein when the value exceeds (+ 0.6 ° C.), the opening degree of the expansion valve increases by an amount corresponding to the magnitude of the difference between the value and (+ 0.6 ° C.). Machine. 外気温度が２℃のときに、前記値が（－２．０℃）未満の場合に、前記膨張弁の開度を一定量だけ減少させ、前記値が（＋４．６℃）を超える場合に、前記膨張弁の開度を一定量だけ増加させる、請求項１記載の空気調和機。When the outside air temperature is 2 ° C., the value is less than (-2.0 ° C.), the opening degree of the expansion valve is reduced by a certain amount, and the value exceeds (+ 4.6 ° C.). The air conditioner according to claim 1, wherein the opening degree of the expansion valve is increased by a certain amount. 外気温度が７℃のときに、前記値が（－４．０℃）未満の場合に、前記膨張弁の開度を一定量だけ減少させ、前記値が（＋０．６℃）を超える場合に、前記膨張弁の開度を一定量だけ増加させる、請求項１記載の空気調和機。When the outside air temperature is 7 ° C. and the value is less than (-4.0 ° C.), the opening degree of the expansion valve is reduced by a certain amount, and when the value exceeds (+ 0.6 ° C.). The air conditioner according to claim 1, wherein the opening degree of the expansion valve is increased by a certain amount. 外気温度が１２℃のときに、前記値が（－２．６℃）未満の場合に、前記膨張弁の開度を一定量だけ減少させ、前記値が（＋１．６℃）を超える場合に、前記膨張弁の開度を一定量だけ増加させる、請求項１記載の空気調和機。When the outside air temperature is 12 ° C. and the value is less than (-2.6 ° C.), the opening degree of the expansion valve is reduced by a certain amount, and when the value exceeds (+ 1.6 ° C.). The air conditioner according to claim 1, wherein the opening degree of the expansion valve is increased by a certain amount. 暖房運転時に、前記吸入温度が前記外気温度よりも小さいときに、前記膨張弁の開度が減少し、前記吸入温度が前記外気温度よりも大きいときに、前記膨張弁の開度が増加する、請求項１記載の空気調和機。 During the heating operation, when the suction temperature is smaller than the outside air temperature, the opening degree of the expansion valve decreases, and when the suction temperature is larger than the outside air temperature, the opening degree of the expansion valve increases. The air conditioner according to claim 1. 前記吸入温度と前記外気温度との差の大きさに応じた量だけ、前記膨張弁の開度が変化する、請求項６記載の空気調和機。The air conditioner according to claim 6, wherein the opening degree of the expansion valve changes by an amount corresponding to the magnitude of the difference between the suction temperature and the outside air temperature. 圧縮機と、凝縮器と、膨張弁と、蒸発器とを含み、冷媒を循環させるように構成された冷媒回路と、
前記圧縮機から吐出される前記冷媒の吐出温度を検出するように構成された第１のセンサとを備え、
前記冷媒は、Ｒ２９０およびＲ１２７０のうちの少なくとも一方を含み、
暖房運転時において、前記圧縮機から吐出される前記冷媒の吐出過熱度が、予め定められた範囲よりも小さい場合に、前記膨張弁の開度が減少し、前記吐出過熱度が、前記予め定められた範囲よりも大きい場合に、前記膨張弁の開度が増加し、
前記予め定められた範囲において、前記冷媒回路を前記冷媒が循環するときのＣＯＰ（Coefficient Of Performance）が前記冷媒回路をＲ３２が循環するときのＣＯＰよりも高く、かつ前記圧縮機が液バック運転しない、空気調和機。 A refrigerant circuit including a compressor, a condenser, an expansion valve, and an evaporator, which is configured to circulate the refrigerant.
A first sensor configured to detect the discharge temperature of the refrigerant discharged from the compressor is provided.
The refrigerant comprises at least one of R290 and R1270.
When the discharge superheat degree of the refrigerant discharged from the compressor is smaller than a predetermined range during the heating operation, the opening degree of the expansion valve is reduced and the discharge superheat degree is determined in advance. When it is larger than the specified range, the opening degree of the expansion valve increases.
Within the predetermined range, the COP (Coefficient Of Performance) when the refrigerant circulates in the refrigerant circuit is higher than the COP when the R32 circulates in the refrigerant circuit, and the compressor does not operate in liquid back. , Air conditioner. 外気温度を検出するように構成された第２のセンサを備え、
前記外気温度がＴＯのときに、前記予め定められた範囲の下限Ｌ（ＳＨｄ）は、以下の式で表される、
L(SHd)=-0.4526*T0+9.575…(A1)
請求項８記載の空気調和機。 Equipped with a second sensor configured to detect outside air temperature,
When the outside air temperature is TO, the lower limit L (SHd) in the predetermined range is expressed by the following equation.
L (SHd) =-0.4526 * T0 + 9.575… (A1)
The air conditioner according to claim 8 . 暖房運転時において、前記圧縮機から吐出される前記冷媒の吐出過熱度が、予め定められた範囲よりも小さい場合に、前記吐出過熱度と前記下限Ｌ（ＳＨｄ）との差の大きさに応じた量だけ、前記膨張弁の開度が減少する、請求項９記載の空気調和機。When the discharge superheat degree of the refrigerant discharged from the compressor is smaller than a predetermined range during the heating operation, it depends on the size of the difference between the discharge superheat degree and the lower limit L (SHd). The air conditioner according to claim 9, wherein the opening degree of the expansion valve is reduced by a certain amount. 外気温度を検出するように構成された第２のセンサを備え、
前記外気温度がＴＯのときに、前記予め定められた範囲の上限Ｕ（ＳＨｄ）は、以下の式で表される、
U(SHd)=-1.1559*T0+19.574…(A2)
請求項８記載の空気調和機。 Equipped with a second sensor configured to detect outside air temperature,
When the outside air temperature is TO, the upper limit U (SHd) in the predetermined range is expressed by the following equation.
U (SHd) =-1.1559 * T0 + 19.574… (A2)
The air conditioner according to claim 8 . 暖房運転時において、前記圧縮機から吐出される前記冷媒の吐出過熱度が、予め定められた範囲よりも大きい場合に、前記吐出過熱度と前記上限Ｕ（ＳＨｄ）との差の大きさに応じた量だけ、前記膨張弁の開度が増加する、請求項１１記載の空気調和機。When the discharge superheat degree of the refrigerant discharged from the compressor is larger than a predetermined range during the heating operation, the difference between the discharge superheat degree and the upper limit U (SHd) is large. The air conditioner according to claim 11, wherein the opening degree of the expansion valve is increased by the amount of the expansion valve. 前記冷媒の凝縮温度を検出するように構成された第２のセンサを備え、前記吐出過熱度は、前記吐出温度から前記凝縮温度を減算することによって得られる値である、請求項８記載の空気調和機。 The air according to claim 8 , further comprising a second sensor configured to detect the condensation temperature of the refrigerant, wherein the discharge superheat degree is a value obtained by subtracting the condensation temperature from the discharge temperature. Harmony machine. 前記圧縮機の潤滑油としてＰＡＧを含む、請求項８記載の空気調和機。 The air conditioner according to claim 8 , which contains PAG as a lubricating oil for the compressor.
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