WO2011070954A1 - Air conditioner and refrigerant amount detection method for air conditioner - Google Patents

Air conditioner and refrigerant amount detection method for air conditioner Download PDF

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Publication number
WO2011070954A1
WO2011070954A1 PCT/JP2010/071481 JP2010071481W WO2011070954A1 WO 2011070954 A1 WO2011070954 A1 WO 2011070954A1 JP 2010071481 W JP2010071481 W JP 2010071481W WO 2011070954 A1 WO2011070954 A1 WO 2011070954A1
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Prior art keywords
refrigerant
liquid level
circuit
temperature
level detection
Prior art date
Application number
PCT/JP2010/071481
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French (fr)
Japanese (ja)
Inventor
隆博 加藤
篤 塩谷
Original Assignee
三菱重工業株式会社
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Application filed by 三菱重工業株式会社 filed Critical 三菱重工業株式会社
Priority to CN201080032591.0A priority Critical patent/CN102472542B/en
Priority to EP10835875.5A priority patent/EP2511630B1/en
Publication of WO2011070954A1 publication Critical patent/WO2011070954A1/en

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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00Arrangement or mounting of control or safety devices
    • F25B49/005Arrangement or mounting of control or safety devices of safety devices
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B40/00Subcoolers, desuperheaters or superheaters
    • F25B40/02Subcoolers
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B40/00Subcoolers, desuperheaters or superheaters
    • F25B40/06Superheaters
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B45/00Arrangements for charging or discharging refrigerant
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00Arrangement or mounting of control or safety devices
    • F25B49/02Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2345/00Details for charging or discharging refrigerants; Service stations therefor
    • F25B2345/003Control issues for charging or collecting refrigerant to or from a cycle
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2345/00Details for charging or discharging refrigerants; Service stations therefor
    • F25B2345/007Details for charging or discharging refrigerants; Service stations therefor characterised by the weighing of refrigerant or oil
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2400/00General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/13Economisers
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2400/00General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/16Receivers
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00Control issues
    • F25B2600/05Refrigerant levels
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00Sensing or detecting of parameters; Sensors therefor
    • F25B2700/04Refrigerant level

Definitions

  • the present invention relates to an air conditioner that can always be filled with an optimum amount of refrigerant at the time of installation, and a refrigerant amount detection method for the air conditioner.
  • a multi-type air conditioner used for air conditioning of buildings and the like includes a compressor, a four-way switching valve, an outdoor heat exchanger, an expansion valve for heating, a receiver and an outdoor fan, an indoor heat exchanger, A plurality of indoor units including a cooling expansion valve, an indoor fan, and the like are connected locally by gas refrigerant pipes and liquid refrigerant pipes.
  • a pipe length that connects between the outdoor unit and the indoor unit when the outdoor unit is preliminarily filled with a predetermined amount of refrigerant and the air conditioner is installed in the field and then trial run is performed.
  • an insufficient amount of refrigerant is additionally charged according to the number of indoor units connected.
  • Patent Documents 1 and 2 disclose techniques for determining that a necessary amount of refrigerant is filled in the refrigerant circuit.
  • Patent Document 1 shows a technique in which a bypass circuit is connected from the predetermined height position of the receiver to the compressor suction side, and an on-off valve, a pressure reducing mechanism, and a temperature detection unit are provided in the bypass circuit. Further, Patent Document 2 is provided with an on-off valve, a pressure reducing mechanism, a heating unit, and a temperature detection unit in the bypass circuit.
  • JP 2002-350014 A Japanese Patent No. 3719246 (see FIG. 1)
  • the liquid level detection circuit is provided with heating means for heating the refrigerant decompressed by the decompression mechanism, and the refrigerant taken out from the receiver is in a gas state.
  • the temperature rise due to heating is large, and in the liquid state, the heat energy from heating is consumed as latent heat of evaporation and the temperature rise is small, so that a sufficient temperature difference can be secured to improve detection accuracy. I have to.
  • it is indispensable to install a heating means in the liquid level detection circuit there is a problem that the configuration becomes complicated.
  • the present invention has been made in view of such circumstances, and is an air that can always detect the refrigerant charging amount with high accuracy without providing any special heating means in the liquid level detection circuit and even under low outside air temperature conditions. It aims at providing the refrigerant
  • the air conditioner and the refrigerant amount detection method for the air conditioner of the present invention employ the following means. That is, the air conditioner according to the first aspect of the present invention shunts a compressor, a compressor, an outdoor heat exchanger, a heating expansion valve, a receiver that stores liquid refrigerant, and a part of the liquid refrigerant, An outdoor unit equipped with a supercooling circuit, etc., which exchanges heat with liquid refrigerant in a supercooling heat exchanger and returns to the suction side of the compressor after decompressing the refrigerant with a decompression mechanism, an indoor heat exchanger, and an expansion valve for cooling
  • an air conditioner that configures a closed-cycle refrigerant circuit by connecting an indoor unit equipped with a gas refrigerant pipe and a liquid refrigerant pipe to the indoor unit including the receiver and the like via the predetermined height position of the receiver and the supercooling circuit
  • a first liquid level detection circuit having an on-off valve and a pressure
  • a bypass circuit connecting a predetermined height position of the receiver and a suction side of the compressor via a supercooling circuit is provided with an opening / closing valve and a pressure reducing mechanism.
  • a temperature detection unit that detects the temperature of the decompressed refrigerant through the circuit or the subcooling circuit including the second liquid level detection circuit, and the first liquid level detection circuit or the second liquid level detection circuit that is taken out from the receiver
  • a refrigerant amount detection unit that detects the temperature of the refrigerant after being depressurized by a temperature detection unit and determines a refrigerant charge amount based on the temperature; Therefore, under a temperature condition of about the cooling rating, by flowing the refrigerant from the receiver into the first liquid level detection
  • the predetermined liquid level is set in the receiver from the temperature difference from when the saturated liquid refrigerant is taken out. It is possible to reliably detect that the liquid refrigerant has accumulated. Therefore, it is possible to detect the refrigerant charge amount with high accuracy by ensuring sufficient temperature difference under a wide range of temperature conditions without being affected by high pressure fluctuations due to outside air temperature, etc. It becomes possible to fill the amount of refrigerant and to stably operate the air conditioner. Further, since the refrigerant can be heated using the supercooling circuit, it is not necessary to provide a heating means specially on the first liquid level detection circuit side, and the configuration can be simplified.
  • An air conditioner according to a second aspect of the present invention is the air conditioner described above, wherein the air conditioner is closed in the vicinity of a branch portion from the refrigerant circuit of the supercooling circuit during the refrigerant charging operation and opened during the normal air conditioning operation.
  • An electromagnetic on-off valve is provided.
  • the air conditioner according to the second aspect is provided with an electromagnetic on-off valve that is closed during the refrigerant charging operation and opened during the normal cooling / heating operation near the branch portion from the refrigerant circuit of the supercooling circuit. Therefore, it is possible to easily switch between the refrigerant charging operation and the normal cooling / heating operation only by opening / closing the electromagnetic opening / closing valve. Therefore, the supercooling circuit can be used in combination as a liquid level detection circuit during the refrigerant charging operation, in addition to the improvement in the capacity during the normal operation, and can contribute to an improvement in the detection accuracy of the refrigerant filling amount.
  • An air conditioner includes an outdoor unit including a compressor, an outdoor heat exchanger, a heating expansion valve, and a receiver for storing liquid refrigerant, an indoor heat exchanger, and a cooling expansion valve.
  • an outdoor unit including a compressor, an outdoor heat exchanger, a heating expansion valve, and a receiver for storing liquid refrigerant, an indoor heat exchanger, and a cooling expansion valve.
  • a gas refrigerant pipe and a liquid refrigerant pipe to form a closed-cycle refrigerant circuit, the predetermined height position of the receiver and the suction side of the compressor
  • a liquid level detection circuit having an on-off valve and a pressure reducing mechanism interposed in a bypass circuit connecting between them, and an on-off valve and a pressure reducing mechanism capable of introducing a part of hot gas from the discharge side to the suction side of the compressor
  • a hot gas bypass circuit a temperature detection unit capable of detecting the temperature of the refrigerant that has passed through the liquid level detection circuit or a mixture of the refriger
  • a liquid level detection circuit including an open / close valve and a pressure reducing mechanism in a bypass circuit connecting between a predetermined height position of the receiver and the suction side of the compressor;
  • a hot gas bypass circuit having an on-off valve and a pressure reducing mechanism capable of introducing a part of hot gas from the discharge side to the suction side of the compressor, and the refrigerant passing through the liquid level detection circuit or the refrigerant and the hot gas bypass circuit
  • the temperature detection unit capable of detecting the temperature of the refrigerant mixed with the introduced hot gas, and the refrigerant taken out from the receiver to the liquid level detection circuit or the refrigerant and the refrigerant introduced via the hot gas bypass circuit
  • a refrigerant amount detection unit that detects the temperature of the refrigerant after being depressurized by a temperature detection unit and determines a refrigerant charge amount based on the temperature; Therefore, under the temperature condition of about the cooling rating, the refrigerant temperature after decompression is detected when the
  • Heating is performed by mixing hot gas, and a sufficient degree of superheat can be secured, so that it is possible to detect that liquid refrigerant of a predetermined liquid level has accumulated in the receiver from the temperature difference from when saturated liquid refrigerant is taken out. . Therefore, the refrigerant charge amount can be detected with high accuracy by sufficiently ensuring the temperature difference under a wide range of temperature conditions without being affected by fluctuations in high pressure due to the outside air temperature, and there is no excess or deficiency. It is possible to fill the optimal amount of refrigerant and to stably operate the air conditioner.
  • the refrigerant quantity detection method for an air conditioner is the above-described refrigerant quantity detection method for an air conditioner, wherein the second liquid level is measured under a temperature condition of a cooling rating during the refrigerant charging operation.
  • a detection circuit is closed by the on-off valve and the first liquid level detection circuit is used.
  • the first liquid level detection circuit is closed by the on-off valve, and the second liquid level detection circuit The liquid level is detected by using each of the above.
  • the second liquid level detection circuit is closed by the on-off valve and the first liquid level detection circuit is closed under the temperature condition of the cooling rating during the refrigerant charging operation.
  • the first liquid level detection circuit is closed by an on-off valve, and the liquid level detection is performed using the second liquid level detection circuit.
  • the saturated gas refrigerant is taken out under a wide range of temperature conditions by using either the first liquid level detection circuit or the second liquid level detection circuit without being influenced by the outside air temperature.
  • the refrigerant quantity detection method for an air conditioner according to a fifth aspect of the present invention is the above-described refrigerant quantity detection method for an air conditioner, wherein the liquid level detection circuit is used in a refrigerant charging operation under a temperature condition of about a cooling rating.
  • the liquid level detection is performed using both the liquid level detection circuit and the hot gas bypass circuit under a low outside air temperature condition.
  • the liquid level detection circuit is used under the temperature condition of the cooling rating during the refrigerant charging operation, and the liquid level detection circuit is used under the low outside air temperature condition.
  • the hot gas bypass circuit are used to detect the liquid level.
  • the saturated gas refrigerant is taken out from the receiver by flowing the refrigerant from the receiver into the first liquid level detection circuit under a temperature condition of about the cooling rating. And when the saturated liquid refrigerant is taken out, it is possible to detect the refrigerant temperature after depressurization and reliably detect that the liquid refrigerant of a predetermined liquid level has accumulated in the receiver from the temperature difference. it can. On the other hand, under a low outside air temperature condition, the saturated gas refrigerant taken out from the receiver flows into the supercooling circuit via the second liquid level detection circuit, so that heat is exchanged with the liquid refrigerant in the supercooling heat exchanger.
  • the degree of superheat can be sufficiently increased, it is possible to reliably detect that the liquid refrigerant of a predetermined liquid level has accumulated in the receiver from the temperature difference from the case where the saturated liquid refrigerant is taken out.
  • the refrigerant charge amount can be detected with high accuracy by ensuring a sufficient temperature difference under a wide range of temperature conditions without being affected by fluctuations in high pressure due to the outside air temperature, and there is no excess or deficiency. It is possible to fill the optimal amount of refrigerant and to stably operate the air conditioner. Further, since the refrigerant can be heated using the supercooling circuit, it is not necessary to provide a heating means specially on the first liquid level detection circuit side, and the configuration can be simplified.
  • the air conditioner and the air conditioner refrigerant amount detection method of the present invention under the temperature condition of the cooling rating, when the saturated gas refrigerant is taken out from the receiver to the liquid level detection circuit, When the liquid refrigerant is taken out, it is possible to detect the refrigerant temperature after depressurization and to detect that a predetermined level of liquid refrigerant has accumulated in the receiver from the temperature difference.
  • the saturated gas refrigerant taken out from the receiver can be heated by mixing the hot gas introduced through the hot gas bypass circuit, and the degree of superheat can be sufficiently increased.
  • the refrigerant charge amount can be detected with high accuracy by sufficiently ensuring the temperature difference under a wide range of temperature conditions without being affected by fluctuations in high pressure due to the outside air temperature, and there is no excess or deficiency. It is possible to fill the optimal amount of refrigerant and to stably operate the air conditioner.
  • FIG. 2 is a pressure-enthalpy diagram when saturated gas refrigerant is bypassed through a first liquid level detection circuit at a high temperature in the air conditioner shown in FIG. 1.
  • FIG. 2 is a pressure-enthalpy diagram when saturated liquid refrigerant is bypassed through a first liquid level detection circuit at a high temperature in the air conditioner shown in FIG. 1.
  • FIG. 2 is a pressure-enthalpy diagram when the saturated gas refrigerant is bypassed through the first liquid level detection circuit at a low temperature in the air conditioner shown in FIG. 1.
  • FIG. 2 is a pressure-enthalpy diagram when the saturated gas refrigerant is bypassed through the second liquid level detection circuit at a low temperature in the air conditioner shown in FIG. 1. It is a refrigerant circuit diagram (a part of which is omitted) of an air conditioner according to a second embodiment of the present invention.
  • 7 is a pressure-enthalpy diagram when a mixed refrigerant of saturated gas refrigerant and hot gas is bypassed through a liquid level detection circuit and a hot gas bypass circuit at a low temperature in the air conditioner shown in FIG. 7 is a pressure-enthalpy diagram when a mixed refrigerant of saturated liquid refrigerant and hot gas is bypassed through a liquid level detection circuit and a hot gas bypass circuit at a low temperature in the air conditioner shown in FIG.
  • FIG. 1 shows a refrigerant circuit diagram of an air conditioner according to the first embodiment of the present invention.
  • the air conditioner 1 is a multi-type air conditioner that is applied to air conditioning of buildings and the like, and includes an outdoor unit 2 and a plurality of indoor units 3 connected in parallel to each other (FIG. 1 shows only one unit). It is composed of).
  • a compressor 10 that compresses the refrigerant, a four-way switching valve 11 that switches the circulation direction of the refrigerant, an outdoor heat exchanger 12 that exchanges heat between the outside air and the refrigerant, and the outside air are passed through the outdoor heat exchanger 12.
  • An outdoor fan 13 for heating, an electric expansion valve for heating (heating expansion valve) 14, a receiver 15 for accumulating condensed liquid refrigerant, and the like are disposed, and a compressor 10, a four-way switching valve 11, an outdoor heat exchanger 12,
  • the outdoor refrigerant circuit 17 is configured by sequentially connecting the heating electric expansion valve 14 and the receiver 15 via the refrigerant pipe 16.
  • a part of the liquid refrigerant is divided into the outdoor refrigerant circuit 17, and the liquid refrigerant is decompressed by the supercooling expansion valve (decompression mechanism) 18, and then sucked into the compressor 10 through the supercooling heat exchanger 19.
  • a supercooling circuit 20 for providing supercooling to the liquid refrigerant in the supercooling heat exchanger 19 is provided.
  • an indoor heat exchanger 30, an indoor fan 31 that circulates indoor air through the indoor heat exchanger 30, an electric expansion valve for cooling (an expansion valve for cooling) 32, and the like are disposed inside the indoor unit 3.
  • the indoor unit 3 and the outdoor unit 2 are connected through a gas refrigerant pipe 33 and a liquid refrigerant pipe 34, whereby a closed cycle refrigerant circuit 35 is configured.
  • the plurality of indoor units 3 are connected in parallel to each other via a gas refrigerant pipe 33 and a liquid refrigerant pipe 34 branched from the gas refrigerant pipe 33 and the liquid refrigerant pipe 34.
  • the air conditioner 1 circulates the refrigerant discharged from the compressor 10 to the outdoor heat exchanger 12 side via the four-way switching valve 11, and receives the receiver 15, the supercooling heat exchanger 19, the cooling electric expansion valve 32, By circulating the indoor heat exchanger 30, the four-way switching valve 11 and the compressor 10 in the clockwise direction, the outdoor heat exchanger 12 functions as a condenser and the indoor heat exchanger 30 functions as an evaporator so that the cooling operation can be performed. It has become.
  • the cooling capacity can be improved.
  • the refrigerant discharged from the compressor 10 is circulated to the indoor heat exchanger 30 side via the four-way switching valve 11, and the supercooling heat exchanger 19, the receiver 15, the heating electric expansion valve 14, the outdoor heat exchanger. 12, the four-way switching valve 11 and the compressor 10 are circulated in the counterclockwise direction so that the indoor heat exchanger 30 functions as a condenser and the outdoor heat exchanger 12 functions as an evaporator, so that a heating operation can be performed. .
  • the lengths of the gas refrigerant pipe 33 and the liquid refrigerant pipe 34 connecting the outdoor unit 2 and the indoor unit 3 vary depending on the environment in which the air conditioner 1 is installed. For this reason, when the outdoor unit 2 is preliminarily filled with a predetermined amount of refrigerant and the air conditioner 1 is installed in the field, the length of the pipe connecting the outdoor unit 2 and the indoor unit 3 when the test operation is performed Insufficient amount of refrigerant must be charged according to the number of indoor units 3 connected. When the refrigerant is additionally charged, the following first liquid level detection circuit 40 and second liquid level detection circuit 45 described below are used so that an appropriate amount of refrigerant can be always charged without depending on the construction level at the site. In addition, a refrigerant amount detection unit 48 is incorporated.
  • the first liquid level detection circuit 40 includes a bypass circuit 41 that can take out a refrigerant from a predetermined height position in the receiver 15 to the suction side of the compressor 10, a capillary tube provided in the bypass circuit 41, an expansion
  • the bypass circuit 41 is connected and joined to the supercooling circuit 20 near the connection portion where the supercooling circuit 20 is connected to the suction pipe of the compressor 10. ing.
  • a thermistor or the like that detects the temperature of the refrigerant depressurized by the depressurization mechanism 42 or the depressurization mechanism 18 that flows through the bypass circuit 41 and the subcooling circuit 20 at a position closer to the suction pipe side of the compressor 10 than the connection junction of the bypass circuit 41
  • a temperature sensor (temperature detection unit) 44 is installed.
  • the second liquid level detection circuit 45 is branched from a position before the decompression mechanism 42 in the bypass circuit 41 constituting the first liquid level detection circuit 40, and is a subcooling expansion valve (decompression mechanism) of the supercooling circuit 20.
  • the circuit connected to the 18 inlet side is provided with an electromagnetic on-off valve 46.
  • the second liquid level detection circuit 45 passes through the supercooling expansion valve (decompression mechanism) 18 and the supercooling heat exchanger 19 in the supercooling circuit 20 for the refrigerant taken out from the receiver 15 during the refrigerant charging operation.
  • 10 is a circuit that returns to the suction side.
  • an electromagnetic on-off valve 47 is provided near the branch portion of the supercooling circuit 20 in order to stop the liquid refrigerant from being diverted to the supercooling circuit 20.
  • the refrigerant amount detector 48 is for determining whether or not an appropriate amount of refrigerant has been charged based on the temperature detected by the temperature sensor 44.
  • liquid refrigerant accumulates in the receiver 15, Detection from the temperature sensor 44 when the liquid level reaches the height position where the bypass circuit 31 is opened and the saturated liquid refrigerant is taken out by the first liquid level detection circuit 40 or the second liquid level detection circuit 45. Detection from the temperature sensor 44 when the saturated gas refrigerant is taken out by the first liquid level detection circuit 40 or the second liquid level detection circuit 45 until the temperature and the liquid refrigerant reach a predetermined height position. Based on the temperature difference from the temperature, it is possible to determine whether or not an appropriate amount of refrigerant has been charged.
  • the refrigerant amount detection unit 48 closes the electromagnetic on-off valve 47 provided in the supercooling circuit 20 during the refrigerant charging operation, and the first liquid level detection circuit 40 or the first level according to the outside air temperature, the high pressure side pressure, or the like.
  • it has a function of controlling opening and closing of the electromagnetic on-off valves 43 and 46. That is, when using the first liquid level detection circuit 40, the electromagnetic switching valve 43 is opened and the electromagnetic switching valve 46 is closed.
  • the electromagnetic switching valve 43 is closed and the electromagnetic switching valve is closed.
  • the valve 46 is opened.
  • the refrigerant circuit 35 is operated as a cooling cycle.
  • the outdoor fan 13 is controlled so that the condensation pressure in the outdoor heat exchanger 12 becomes a predetermined value, and at the outlet of the indoor heat exchanger 30, a predetermined superheat degree is given to the refrigerant.
  • the opening degree of the electric expansion valve 32 is controlled. Thereby, the refrigerant can be filled in the refrigerant circuit 35 in a state where the liquid refrigerant pipe 34 is filled with the liquid refrigerant having a predetermined density.
  • the electromagnetic on-off valve 47 in the supercooling circuit 20 is closed and, for example, when the outside air temperature is high, such as a cooling rating, the electromagnetic on-off valve 43 is opened, the electromagnetic on-off valve 46 is closed, and the low outside air temperature is low. Sometimes, the electromagnetic on-off valve 43 is closed and the electromagnetic on-off valve 46 is opened.
  • the refrigerant circulation amount in the refrigerant circuit 35 is gradually increased, and the liquid level of the refrigerant in the receiver 15 gradually increases.
  • the liquid refrigerant is placed in the receiver 15 up to a height position where the bypass circuit 41 is open. Until the gas level is accumulated, the saturated gas refrigerant in the receiver 15 flows to the first liquid level detection circuit 40, and when the liquid level of the liquid refrigerant rises to a height position where the bypass circuit 41 is opened, The saturated liquid refrigerant flows into the first liquid level detection circuit 40.
  • the high pressure may be lowered by controlling the rotation speed of the compressor 10, the rotation speed of the outdoor fan 13, and the like.
  • the saturated gas refrigerant or saturated liquid refrigerant is decompressed to a low pressure state by the decompression mechanism 43, and the temperature drops.
  • the refrigerant amount detection unit looks at the temperature difference between the temperature drop from the saturated gas refrigerant state and the temperature drop from the saturated liquid refrigerant state. 48 detects that the liquid refrigerant of a predetermined liquid level has accumulated in the receiver 15, and determines that the required amount of refrigerant has been filled. At this point, the refrigerant filling operation is terminated.
  • the temperature difference is sufficiently secured.
  • the pressure in the receiver 15 is around 2 MPa (when the refrigerant is R410A).
  • the pressure is reduced by the pressure reducing mechanism 43, the temperature is lowered to the point A, and a certain degree of superheat SH can be secured.
  • the electromagnetic on-off valve 43 is closed and the electromagnetic on-off valve 46 is opened.
  • the liquid level detection circuit is switched to the second liquid level detection circuit 45, the refrigerant taken out from the receiver 15 is allowed to flow to the supercooling circuit 20 via the second liquid level detection circuit 45.
  • the refrigerant taken out to the supercooling circuit 20 via the second liquid level detection circuit 45 is decompressed by the supercooling expansion valve (decompression mechanism) 18, and then is cooled by the supercooling heat exchanger 19. The heat is exchanged and heated, evaporated, and returned to the suction side of the compressor 10.
  • a temperature difference of a certain value or more is secured between when the saturated gas refrigerant is taken out and when the saturated liquid refrigerant is taken out.
  • the saturated liquid refrigerant is depressurized by the depressurization mechanism 18 and dropped in temperature, then heated and evaporated by the supercooling heat exchanger 19, and the superheat degree is 0 at point D on the saturated gas line. It becomes a refrigerant at °C.
  • the saturated gas refrigerant is depressurized and drops in temperature to the point C, and then heated by the supercooling heat exchanger 19, whereby the superheat degree SH is increased to the point E. For this reason, a sufficient temperature difference can be ensured, and the refrigerant amount detection unit 48 can reliably detect that an appropriate amount of refrigerant has been charged.
  • the saturated gas refrigerant taken out from the receiver 15 is allowed to flow into the supercooling circuit 20 via the second liquid level detection circuit 45 even under conditions where the pressure on the high pressure side cannot be secured at low outside air temperature. Therefore, the supercooling heat exchanger 19 heats the liquid refrigerant for heating, and the degree of superheat can be sufficiently increased. Therefore, the liquid refrigerant of a predetermined liquid level is introduced into the receiver 15 from the temperature difference from when the saturated liquid refrigerant is taken out. Can be reliably detected.
  • the refrigerant charge amount is detected with high accuracy by ensuring a sufficient temperature difference between the saturated gas refrigerant and the saturated liquid refrigerant under a wide range of temperature conditions without being influenced by high pressure fluctuations caused by the outside air temperature. It is possible to fill the optimal amount of refrigerant without excess and deficiency, and to operate the air conditioner 1 stably. Further, since the refrigerant can be heated using the supercooling circuit 20, it is not necessary to provide a heating means specially on the first liquid level detection circuit 40 side, and the configuration can be simplified.
  • an electromagnetic on-off valve 47 that is closed during the refrigerant charging operation and opened during the normal cooling / heating operation is provided near the branch portion from the refrigerant circuit 35 of the supercooling circuit 20. Switching between the refrigerant charging operation and the normal air conditioning operation can be easily performed only by opening / closing the electromagnetic opening / closing valve 47. Therefore, the supercooling circuit 20 can be used in combination as a liquid level detection circuit during the refrigerant charging operation, in addition to improving the capability during the normal cooling / heating operation, and can contribute to an improvement in the detection accuracy of the refrigerant filling amount. Moreover, since the existing temperature sensor provided in the supercooling circuit 20 can be shared as the temperature sensor 44, a temperature sensor can be saved.
  • FIGS. 6 differs from the first embodiment described above in that a hot gas bypass circuit 50 is provided instead of the second liquid level detection circuit 45. Since other points are the same as those in the first embodiment, description thereof will be omitted.
  • a capillary is connected to a bypass circuit 41 that connects a predetermined height position in the receiver 15 and the suction side of the compressor 10.
  • a liquid level detection circuit 40 having a pressure reducing mechanism 42 and an electromagnetic opening / closing valve 43 including a tube, an expansion valve, etc., an electromagnetic opening / closing valve 51 capable of introducing a part of hot gas from the discharge side to the suction side of the compressor 10
  • Temperature of a hot gas bypass circuit 50 having a pressure reducing mechanism 52 including a capillary tube, an expansion valve, etc., and a refrigerant that has passed through the liquid level detection circuit 40 or a mixture of the refrigerant and hot gas introduced from the hot gas bypass circuit 50
  • a temperature sensor 53 for detecting.
  • the refrigerant amount detection unit 48 detects that liquid refrigerant of a predetermined liquid level has accumulated in the receiver 15 based on the detection value from the temperature sensor 53, and fills the refrigerant. The amount can be determined. In addition, the refrigerant quantity detection unit 48 determines whether to use only the liquid level detection circuit 40 according to the outside air temperature, the high pressure side pressure, or the like during the refrigerant charging operation, or to perform the liquid level detection using the hot gas bypass circuit 50 together. When the determination is made, the electromagnetic on / off valves 43 and 51 are controlled to open / close.
  • the electromagnetic switching valve 43 is opened and the electromagnetic switching valve 51 is closed, and when the liquid level detection circuit 40 and the hot gas bypass circuit 50 are used together, the electromagnetic switching is performed. Both valves 43 and 51 are opened.
  • the liquid level detection circuit 40 including the pressure reducing mechanism 42 and the electromagnetic opening / closing valve 43 is provided between the predetermined height position of the receiver 15 and the suction side of the compressor 10, and the discharge side and suction of the compressor 10 are provided.
  • a hot gas bypass circuit 50 in which an electromagnetic on-off valve 41 and a pressure reducing mechanism 42 are interposed is provided between the compressor 10 and the hot gas discharged from the compressor 10 via the hot gas bypass circuit 50.
  • the electromagnetic on-off valve 51 When the outside air temperature is low, the electromagnetic on-off valve 51 is opened, and hot gas decompressed by the decompression mechanism 52 is introduced to the suction side of the compressor 10 via the hot gas bypass circuit 50, so that the hot gas is discharged from the receiver 15.
  • the refrigerant can be mixed with the refrigerant taken out by the surface detection circuit 40 and heated. For this reason, the saturated gas refrigerant taken out from the receiver 15 to the liquid level detection circuit 40 is mixed with hot gas decompressed to the point G after being decompressed and dropped to the point F as shown in FIG.
  • the degree of superheat SH is raised to the H point.
  • the saturated liquid refrigerant taken out from the receiver 15 is depressurized and evaporated, drops in temperature to the I point, and then mixed with the hot gas depressurized to the J point to obtain the K point.
  • the degree of superheat cannot be ensured. Therefore, a sufficient temperature difference can be ensured, and the refrigerant amount detection unit 48 can reliably detect that an appropriate amount of refrigerant has been charged.
  • the air conditioner 1 can be stably operated by filling an optimal amount of refrigerant without excess or deficiency.
  • the hot gas is directly mixed with the refrigerant from the liquid level detection circuit 40 to heat the refrigerant, so that the temperature can be detected without a time delay, and therefore the refrigerant charge amount is detected.
  • the accuracy can be further increased.
  • the existing suction temperature sensor provided in the suction pipe of the compressor 10 can be shared as the temperature sensor 53, the temperature sensor can be saved.
  • the present invention is not limited to the invention according to the above-described embodiment, and can be modified as appropriate without departing from the scope of the invention.
  • the supercooling circuit 20 is omitted in the second embodiment
  • the invention according to the second embodiment may be applied to the air conditioner 1 including the supercooling circuit 20.
  • the bypass circuit 41 of the first liquid level detection circuit (liquid level detection circuit) 40 is inserted and connected from the upper surface of the receiver 15. As long as it is connected so as to be opened at a predetermined height position, it may be inserted from the side surface or the lower surface of the receiver 15 so as to be opened at a predetermined height position.

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  • Physics & Mathematics (AREA)
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Abstract

Provided are an air conditioner and refrigerant amount detection method for an air conditioner, which make it possible to constantly detect the amount of charged refrigerant with high accuracy without a heating means specially provided in a liquid level detecting circuit and even under low external temperature. An air conditioner (1), which is provided with a supercooling circuit (20), comprises: a first liquid level detecting circuit (40) which connects one position at a predetermined height inside a receiver (15) to the inlet side of a compressor (10) via the supercooling circuit (20); a second liquid level detecting circuit (45) which is branched from a bypass circuit (41) of the first liquid level detecting circuit (40) and acts as a bypass for leading, to the supercooling circuit (20), the refrigerant that has been taken out from the receiver (15); a temperature detecting unit (44) which detects the temperature of the refrigerant that has been depressurized by passing through the first liquid level detecting circuit (40) or the second liquid level detecting circuit (45); and a refrigerant amount detecting unit (48) which detects, by the temperature detecting unit (44), the post-depressurization temperature of the refrigerant that has been taken out from the receiver (15) via the first liquid level detecting circuit (40) or the second liquid level detecting circuit (45), and determines the amount of charged refrigerant on the basis of the thus detected temperature.

Description

空気調和機および空気調和機の冷媒量検出方法Air conditioner and refrigerant amount detection method for air conditioner
 本発明は、据付け時に、常に最適な量の冷媒を充填することができる空気調和機および空気調和機の冷媒量検出方法に関するものである。 The present invention relates to an air conditioner that can always be filled with an optimum amount of refrigerant at the time of installation, and a refrigerant amount detection method for the air conditioner.
 ビル等の空調に用いられるマルチタイプの空気調和機は、圧縮機、四方切換弁、室外熱交換器、暖房用膨張弁、レシーバおよび室外ファン等を備えている室外機と、室内熱交換器、冷房用膨張弁および室内ファン等を備えている複数台の室内機との間を現地でガス冷媒配管および液冷媒配管により接続するようにしている。このような空気調和機では、予め室外機に所定量の冷媒を充填しておき、現地において空気調和機を据付けした後、試運転するときに、室外機と室内機との間を接続する配管長さや室内機の接続台数等に応じて不足量の冷媒を追加充填するようにしている。 A multi-type air conditioner used for air conditioning of buildings and the like includes a compressor, a four-way switching valve, an outdoor heat exchanger, an expansion valve for heating, a receiver and an outdoor fan, an indoor heat exchanger, A plurality of indoor units including a cooling expansion valve, an indoor fan, and the like are connected locally by gas refrigerant pipes and liquid refrigerant pipes. In such an air conditioner, a pipe length that connects between the outdoor unit and the indoor unit when the outdoor unit is preliminarily filled with a predetermined amount of refrigerant and the air conditioner is installed in the field and then trial run is performed. In addition, an insufficient amount of refrigerant is additionally charged according to the number of indoor units connected.
 かかる空気調和機において、追加する冷媒の充填量を現地の工事レベルに依存することなく、常に適正な量の冷媒を充填できるようにするため、冷媒充填運転時に、冷媒回路中のレシーバ内に溜まってくる液冷媒が所定の液面レベルに達したことを検出する液面検出回路を設け、この液面検出回路によりレシーバ内に所定液面の液冷媒が溜まったことが検出されたことを以って、冷媒回路内に必要量の冷媒が充填されていると判定するようにした技術が特許文献1,2により開示されている。 In such an air conditioner, in order to always be able to charge an appropriate amount of refrigerant without depending on the local construction level, the amount of refrigerant to be added is always stored in the receiver in the refrigerant circuit during the refrigerant charging operation. A liquid level detection circuit is provided for detecting that the incoming liquid refrigerant has reached a predetermined liquid level, and the liquid level detection circuit detects that the liquid refrigerant of the predetermined liquid level has accumulated in the receiver. Thus, Patent Documents 1 and 2 disclose techniques for determining that a necessary amount of refrigerant is filled in the refrigerant circuit.
 この特許文献1は、レシーバの所定高さ位置から圧縮機吸入側にバイパス回路を接続し、このバイパス回路中に開閉弁、減圧機構、温度検出部を設けた技術を示している。また、特許文献2は、バイパス回路中に開閉弁、減圧機構、加熱手段、温度検出部を設けたものであり、バイパス回路にレシーバから飽和状態のガス冷媒が取出された場合と、飽和状態の液冷媒が取出された場合とにおいて、それぞれ減圧後の冷媒温度を測定し、その温度差からレシーバ内に所定液面の液冷媒が溜まったことを検出することにより、冷媒量を判定するようにした技術を示している。 This Patent Document 1 shows a technique in which a bypass circuit is connected from the predetermined height position of the receiver to the compressor suction side, and an on-off valve, a pressure reducing mechanism, and a temperature detection unit are provided in the bypass circuit. Further, Patent Document 2 is provided with an on-off valve, a pressure reducing mechanism, a heating unit, and a temperature detection unit in the bypass circuit. When the saturated gas refrigerant is taken out from the receiver to the bypass circuit, When the liquid refrigerant is taken out, the refrigerant temperature after depressurization is measured, and the refrigerant amount is determined by detecting that the liquid refrigerant of the predetermined liquid level has accumulated in the receiver from the temperature difference. Show the technology.
特開2002-350014号公報(図1参照)JP 2002-350014 A (see FIG. 1) 特許第3719246号公報(図1参照)Japanese Patent No. 3719246 (see FIG. 1)
 しかしながら、特許文献1に開示された技術の場合、外気温等が高く、圧縮機の吐出側圧力(高圧)が高くなって、圧力-エンタルピ線図上の飽和ガス線の傾きが左肩上がりとなる圧力条件下では、飽和状態のガス冷媒を取出して減圧したとき、気液二相状態となることがある。この場合、冷媒の急激な温度降下を検出してしまい、液冷媒が所定液面レベルに到達していると誤判定してしまうおそれがあり、検出精度を確保できないという課題があった。 However, in the case of the technique disclosed in Patent Document 1, the outside air temperature is high, the discharge side pressure (high pressure) of the compressor is high, and the slope of the saturated gas line on the pressure-enthalpy diagram increases to the left. Under pressure conditions, a gas-liquid two-phase state may occur when a saturated gas refrigerant is taken out and decompressed. In this case, a sudden temperature drop of the refrigerant is detected, and it may be erroneously determined that the liquid refrigerant has reached a predetermined liquid level, and there is a problem that the detection accuracy cannot be ensured.
 一方、特許文献2に開示された技術は、上記課題を解決するため、液面検出回路に減圧機構で減圧された冷媒を加熱する加熱手段を設け、レシーバから取出された冷媒がガス状態の場合は加熱による温度上昇が大きく、液状態の場合は加熱による熱エネルギーが蒸発潜熱として消費されて温度上昇が小さいことを利用し、温度差を十分に確保できるようにして、検出精度を向上させるようにしている。しかし、液面検出回路に加熱手段を設置することが不可欠となるため、構成が複雑化するという問題があった。また、特許文献1,2のいずれの技術においても、低外気温時等で吐出側圧力(高圧圧力)が十分に上昇されない場合、レシーバから取出されるガス冷媒の過熱度が確保できなくなり、検出精度が低下するという問題が内在している。 On the other hand, in the technique disclosed in Patent Document 2, in order to solve the above problem, the liquid level detection circuit is provided with heating means for heating the refrigerant decompressed by the decompression mechanism, and the refrigerant taken out from the receiver is in a gas state. The temperature rise due to heating is large, and in the liquid state, the heat energy from heating is consumed as latent heat of evaporation and the temperature rise is small, so that a sufficient temperature difference can be secured to improve detection accuracy. I have to. However, since it is indispensable to install a heating means in the liquid level detection circuit, there is a problem that the configuration becomes complicated. Also, in any of the techniques disclosed in Patent Documents 1 and 2, if the discharge side pressure (high pressure) is not sufficiently increased at low outside air temperature, the degree of superheat of the gas refrigerant taken out from the receiver cannot be secured, and detection is performed. The problem of reduced accuracy is inherent.
 本発明は、このような事情に鑑みてなされたものであって、液面検出回路に特別に加熱手段を設けることなく、また低外気温条件下でも冷媒充填量を常に高精度で検出できる空気調和機および空気調和機の冷媒量検出方法を提供することを目的とする。 The present invention has been made in view of such circumstances, and is an air that can always detect the refrigerant charging amount with high accuracy without providing any special heating means in the liquid level detection circuit and even under low outside air temperature conditions. It aims at providing the refrigerant | coolant amount detection method of a conditioner and an air conditioner.
 上記した課題を解決するために、本発明の空気調和機および空気調和機の冷媒量検出方法は、以下の手段を採用する。
 すなわち、本発明の第1の態様にかかる空気調和機は、圧縮機、圧縮機、室外熱交換器、暖房用膨張弁、液冷媒を貯留するレシーバ、および液冷媒の一部を分流し、該冷媒を減圧機構で減圧した後、過冷却熱交換器で液冷媒と熱交換させ、前記圧縮機の吸入側に戻す過冷却回路等を備えた室外機と、室内熱交換器、冷房用膨張弁等を備えた室内機とをガス冷媒配管および液冷媒配管により接続し、閉サイクルの冷媒回路を構成している空気調和機において、前記レシーバの所定高さ位置と前記過冷却回路を介して前記圧縮機の吸入側との間を接続するバイパス回路に開閉弁および減圧機構を介装した第1液面検出回路と、前記バイパス回路から分岐され、前記レシーバから取出された冷媒を前記過冷却回路の減圧機構の入口側にバイパスする開閉弁を介装した第2液面検出回路と、前記第1液面検出回路または前記第2液面検出回路を含む前記過冷却回路を経て減圧された冷媒の温度を検出する温度検出部と、前記レシーバから前記第1液面検出回路または前記第2液面検出回路を介して取出された冷媒の減圧後の温度を前記温度検出部で検出し、該温度に基づいて冷媒充填量を判定する冷媒量検出部と、を備えていることを特徴とする。
In order to solve the above-described problems, the air conditioner and the refrigerant amount detection method for the air conditioner of the present invention employ the following means.
That is, the air conditioner according to the first aspect of the present invention shunts a compressor, a compressor, an outdoor heat exchanger, a heating expansion valve, a receiver that stores liquid refrigerant, and a part of the liquid refrigerant, An outdoor unit equipped with a supercooling circuit, etc., which exchanges heat with liquid refrigerant in a supercooling heat exchanger and returns to the suction side of the compressor after decompressing the refrigerant with a decompression mechanism, an indoor heat exchanger, and an expansion valve for cooling In an air conditioner that configures a closed-cycle refrigerant circuit by connecting an indoor unit equipped with a gas refrigerant pipe and a liquid refrigerant pipe to the indoor unit including the receiver and the like via the predetermined height position of the receiver and the supercooling circuit A first liquid level detection circuit having an on-off valve and a pressure reducing mechanism interposed in a bypass circuit connecting to the suction side of the compressor; and a refrigerant branched from the bypass circuit and taken out from the receiver Bypass to the inlet side of the decompression mechanism A second liquid level detection circuit provided with a valve closing; and a temperature detection unit that detects the temperature of the refrigerant decompressed through the first liquid level detection circuit or the supercooling circuit including the second liquid level detection circuit; The temperature detection unit detects the temperature after depressurization of the refrigerant taken out from the receiver via the first liquid level detection circuit or the second liquid level detection circuit, and determines the refrigerant filling amount based on the temperature And a refrigerant amount detection unit.
 前記第1の態様にかかる空気調和機は、レシーバの所定高さ位置と過冷却回路を介して圧縮機の吸入側との間を接続するバイパス回路に開閉弁および減圧機構を介装した第1液面検出回路と、バイパス回路から分岐され、レシーバから取出された冷媒を過冷却回路の減圧機構の入口側にバイパスする開閉弁を介装した第2液面検出回路と、第1液面検出回路または第2液面検出回路を含む過冷却回路を経て減圧された冷媒の温度を検出する温度検出部と、レシーバから第1液面検出回路または第2液面検出回路を介して取出された冷媒の減圧後の温度を温度検出部で検出し、該温度に基づいて冷媒充填量を判定する冷媒量検出部と、を備えている。従って、冷房定格程度の温度条件下では、レシーバからの冷媒を第1液面検出回路に流し込むことにより、レシーバから飽和ガス冷媒が取出された場合と、飽和液冷媒が取出された場合とにおいて、それぞれ減圧後の冷媒温度を検出し、その温度差からレシーバ内に所定液面の液冷媒が溜まったことを確実に検出することができる。一方、低外気温条件下では、高圧の低下によりレシーバの圧力が低下し、飽和ガス冷媒が取出されている場合、減圧後の冷媒温度を検出しても過熱度を十分確保できないことから、飽和液冷媒が取出された場合との峻別ができず、誤判定される可能性があったが、かかる条件下でも、レシーバから取出された飽和ガス冷媒を、第2液面検出回路を介して過冷却回路に流し込むことにより、過冷却熱交換器で液冷媒と熱交換させて加熱し、過熱度を十分大きくできるため、飽和液冷媒が取出された場合との温度差からレシーバ内に所定液面の液冷媒が溜まったことを確実に検出することができる。従って、外気温による高圧の変動等に左右されることなく、広範囲な温度条件下において、上記温度差を十分に確保して高精度で冷媒充填量を検出することができ、過不足のない最適量の冷媒を充填し、空気調和機を安定して運転することが可能となる。また、過冷却回路を利用して冷媒を加熱できるため、第1液面検出回路側に特別に加熱手段を設ける必要がなく、構成を簡素化することができる。 In the air conditioner according to the first aspect, a bypass circuit connecting a predetermined height position of the receiver and a suction side of the compressor via a supercooling circuit is provided with an opening / closing valve and a pressure reducing mechanism. A liquid level detection circuit; a second liquid level detection circuit including an on-off valve that bypasses the refrigerant branched from the bypass circuit and taken out from the receiver to the inlet side of the decompression mechanism of the supercooling circuit; and the first liquid level detection A temperature detection unit that detects the temperature of the decompressed refrigerant through the circuit or the subcooling circuit including the second liquid level detection circuit, and the first liquid level detection circuit or the second liquid level detection circuit that is taken out from the receiver A refrigerant amount detection unit that detects the temperature of the refrigerant after being depressurized by a temperature detection unit and determines a refrigerant charge amount based on the temperature; Therefore, under a temperature condition of about the cooling rating, by flowing the refrigerant from the receiver into the first liquid level detection circuit, when the saturated gas refrigerant is taken out from the receiver, and when the saturated liquid refrigerant is taken out, It is possible to detect the refrigerant temperature after depressurization and reliably detect that the liquid refrigerant of a predetermined liquid level has accumulated in the receiver from the temperature difference. On the other hand, under low outside air temperature conditions, when the pressure of the receiver decreases due to a decrease in high pressure and saturated gas refrigerant is taken out, it is not possible to secure a sufficient degree of superheat even if the refrigerant temperature after decompression is detected. There was a possibility that the liquid refrigerant could not be distinguished from the case where it was taken out and could be misjudged. However, even under such conditions, the saturated gas refrigerant taken out from the receiver was excessively passed through the second liquid level detection circuit. By flowing into the cooling circuit, heat is exchanged with the liquid refrigerant in the supercooling heat exchanger and heating is performed, and the degree of superheat can be sufficiently increased.Therefore, the predetermined liquid level is set in the receiver from the temperature difference from when the saturated liquid refrigerant is taken out. It is possible to reliably detect that the liquid refrigerant has accumulated. Therefore, it is possible to detect the refrigerant charge amount with high accuracy by ensuring sufficient temperature difference under a wide range of temperature conditions without being affected by high pressure fluctuations due to outside air temperature, etc. It becomes possible to fill the amount of refrigerant and to stably operate the air conditioner. Further, since the refrigerant can be heated using the supercooling circuit, it is not necessary to provide a heating means specially on the first liquid level detection circuit side, and the configuration can be simplified.
 本発明の第2の態様にかかる空気調和機は、上記の空気調和機において、前記過冷却回路の前記冷媒回路からの分岐部付近に、冷媒充填運転時に閉とされ、通常の冷暖房運転時には開とされる電磁開閉弁が設けられていることを特徴とする。 An air conditioner according to a second aspect of the present invention is the air conditioner described above, wherein the air conditioner is closed in the vicinity of a branch portion from the refrigerant circuit of the supercooling circuit during the refrigerant charging operation and opened during the normal air conditioning operation. An electromagnetic on-off valve is provided.
前記第2の態様にかかる空気調和機は、過冷却回路の冷媒回路からの分岐部付近に、冷媒充填運転時に閉とされ、通常の冷暖房運転時には開とされる電磁開閉弁が設けられているため、電磁開閉弁の開閉操作のみによって簡単に冷媒充填運転と通常の冷暖房運転との切換えを行うことができる。従って、過冷却回路を、通常運転時の能力向上以外に、冷媒充填運転時の液面検出回路として併用し、冷媒充填量の検出精度の向上に資することができる。 The air conditioner according to the second aspect is provided with an electromagnetic on-off valve that is closed during the refrigerant charging operation and opened during the normal cooling / heating operation near the branch portion from the refrigerant circuit of the supercooling circuit. Therefore, it is possible to easily switch between the refrigerant charging operation and the normal cooling / heating operation only by opening / closing the electromagnetic opening / closing valve. Therefore, the supercooling circuit can be used in combination as a liquid level detection circuit during the refrigerant charging operation, in addition to the improvement in the capacity during the normal operation, and can contribute to an improvement in the detection accuracy of the refrigerant filling amount.
 本発明の第3の態様にかかる空気調和機は、圧縮機、室外熱交換器、暖房用膨張弁および液冷媒を貯留するレシーバ等を備えた室外機と、室内熱交換器、冷房用膨張弁等を備えた室内機とをガス冷媒配管および液冷媒配管により接続し、閉サイクルの冷媒回路を構成している空気調和機において、前記レシーバの所定高さ位置と前記圧縮機の吸入側との間を接続するバイパス回路に開閉弁および減圧機構を介装した液面検出回路と、前記圧縮機の吐出側から吸入側にホットガスの一部を導入可能な開閉弁および減圧機構を備えているホットガスバイパス回路と、前記液面検出回路を経た冷媒または該冷媒と前記ホットガスバイパス回路を経て導入されたホットガスとが混合された冷媒の温度を検出可能な温度検出部と、前記レシーバから前記液面検出回路に取出された冷媒または該冷媒と前記ホットガスバイパス回路を経て導入された冷媒との混合冷媒の減圧後の温度を前記温度検出部で検出し、該温度に基づいて冷媒充填量を判定する冷媒量検出部と、を備えていることを特徴とする。 An air conditioner according to a third aspect of the present invention includes an outdoor unit including a compressor, an outdoor heat exchanger, a heating expansion valve, and a receiver for storing liquid refrigerant, an indoor heat exchanger, and a cooling expansion valve. Are connected to each other by a gas refrigerant pipe and a liquid refrigerant pipe to form a closed-cycle refrigerant circuit, the predetermined height position of the receiver and the suction side of the compressor A liquid level detection circuit having an on-off valve and a pressure reducing mechanism interposed in a bypass circuit connecting between them, and an on-off valve and a pressure reducing mechanism capable of introducing a part of hot gas from the discharge side to the suction side of the compressor A hot gas bypass circuit, a temperature detection unit capable of detecting the temperature of the refrigerant that has passed through the liquid level detection circuit or a mixture of the refrigerant and the hot gas introduced through the hot gas bypass circuit, and the receiver in front A temperature after decompression of the refrigerant taken out by the liquid level detection circuit or a mixed refrigerant of the refrigerant and the refrigerant introduced through the hot gas bypass circuit is detected by the temperature detection unit, and the refrigerant filling amount based on the temperature A refrigerant amount detection unit for determining whether or not.
 前記第3の態様にかかる空気調和機によれば、レシーバの所定高さ位置と圧縮機の吸入側との間を接続するバイパス回路に開閉弁および減圧機構を介装した液面検出回路と、圧縮機の吐出側から吸入側にホットガスの一部を導入可能な開閉弁および減圧機構を備えているホットガスバイパス回路と、液面検出回路を経た冷媒または該冷媒とホットガスバイパス回路を経て導入されたホットガスとが混合された冷媒の温度を検出可能な温度検出部と、レシーバから液面検出回路に取出された冷媒または該冷媒とホットガスバイパス回路を経て導入された冷媒との混合冷媒の減圧後の温度を温度検出部で検出し、該温度に基づいて冷媒充填量を判定する冷媒量検出部と、を備えている。従って、冷房定格程度の温度条件下では、レシーバから液面検出回路に飽和状態のガス冷媒が取出された場合と、飽和液冷媒が取出された場合とにおいて、それぞれ減圧後の冷媒温度を検出し、その温度差からレシーバ内に所定液面の液冷媒が溜まったことを検出することができる。一方、低外気温条件下では、高圧の低下によりレシーバ内の圧力が低下し、飽和ガス冷媒が取出されている場合、減圧後の冷媒温度を検出しても過熱度が確保できないことから、飽和液冷媒が取出された場合との峻別ができず、誤判定される可能性があったが、かかる条件下でも、レシーバから取出された飽和ガス冷媒に対してホットガスバイパス回路を経て導入されたホットガスを混合することにより加熱し、過熱度を十分確保できるため、飽和液冷媒が取出された場合との温度差からレシーバ内に所定液面の液冷媒が溜まったことを検出することができる。従って、外気温による高圧の変動等にも左右されることなく、広範囲な温度条件下において、上記温度差を十分に確保して高精度で冷媒充填量を検出することができ、過不足のない最適量の冷媒を充填し、空気調和機を安定して運転することが可能となる。 According to the air conditioner according to the third aspect, a liquid level detection circuit including an open / close valve and a pressure reducing mechanism in a bypass circuit connecting between a predetermined height position of the receiver and the suction side of the compressor; A hot gas bypass circuit having an on-off valve and a pressure reducing mechanism capable of introducing a part of hot gas from the discharge side to the suction side of the compressor, and the refrigerant passing through the liquid level detection circuit or the refrigerant and the hot gas bypass circuit The temperature detection unit capable of detecting the temperature of the refrigerant mixed with the introduced hot gas, and the refrigerant taken out from the receiver to the liquid level detection circuit or the refrigerant and the refrigerant introduced via the hot gas bypass circuit A refrigerant amount detection unit that detects the temperature of the refrigerant after being depressurized by a temperature detection unit and determines a refrigerant charge amount based on the temperature; Therefore, under the temperature condition of about the cooling rating, the refrigerant temperature after decompression is detected when the saturated gas refrigerant is taken out from the receiver to the liquid level detection circuit and when the saturated liquid refrigerant is taken out, respectively. From the temperature difference, it can be detected that liquid refrigerant of a predetermined liquid level has accumulated in the receiver. On the other hand, under low outside air temperature conditions, when the pressure in the receiver decreases due to a decrease in high pressure and saturated gas refrigerant is taken out, the degree of superheat cannot be secured even if the refrigerant temperature after decompression is detected. Although it could not be distinguished from the case where the liquid refrigerant was taken out, there was a possibility of erroneous determination, but even under such conditions, the saturated gas refrigerant taken out from the receiver was introduced via the hot gas bypass circuit. Heating is performed by mixing hot gas, and a sufficient degree of superheat can be secured, so that it is possible to detect that liquid refrigerant of a predetermined liquid level has accumulated in the receiver from the temperature difference from when saturated liquid refrigerant is taken out. . Therefore, the refrigerant charge amount can be detected with high accuracy by sufficiently ensuring the temperature difference under a wide range of temperature conditions without being affected by fluctuations in high pressure due to the outside air temperature, and there is no excess or deficiency. It is possible to fill the optimal amount of refrigerant and to stably operate the air conditioner.
 本発明の第4の態様にかかる空気調和機の冷媒量検出方法は、上述の空気調和機の冷媒量検出方法において、冷媒充填運転時、冷房定格程度の温度条件下では、前記第2液面検出回路を前記開閉弁により閉鎖して前記第1液面検出回路を使用し、低外気温条件下では、前記第1液面検出回路を前記開閉弁により閉鎖し、前記第2液面検出回路を使用してそれぞれ液面検出を行うことを特徴とする。 The refrigerant quantity detection method for an air conditioner according to a fourth aspect of the present invention is the above-described refrigerant quantity detection method for an air conditioner, wherein the second liquid level is measured under a temperature condition of a cooling rating during the refrigerant charging operation. A detection circuit is closed by the on-off valve and the first liquid level detection circuit is used. Under a low outside air temperature condition, the first liquid level detection circuit is closed by the on-off valve, and the second liquid level detection circuit The liquid level is detected by using each of the above.
 前記第4の態様によれば、上述の空気調和機において、冷媒充填運転時、冷房定格程度の温度条件下では、第2液面検出回路を開閉弁により閉鎖して第1液面検出回路を使用し、低外気温条件下では、第1液面検出回路を開閉弁により閉鎖し、第2液面検出回路を使用してそれぞれ液面検出を行うようにしている。その結果、外気温に左右されることなく、第1液面検出回路または第2液面検出回路のいずれかを使用することにより、広範囲にわたる温度条件下において、飽和ガス冷媒が取出された場合と飽和液冷媒が取出された場合との温度差から、レシーバ内に所定液面の液冷媒が溜まったことを検出し、冷媒充填量を高精度で検出することができる。従って、空気調和機に対して過不足のない最適量の冷媒を充填することができる。 According to the fourth aspect, in the air conditioner described above, the second liquid level detection circuit is closed by the on-off valve and the first liquid level detection circuit is closed under the temperature condition of the cooling rating during the refrigerant charging operation. In use, under a low outside air temperature condition, the first liquid level detection circuit is closed by an on-off valve, and the liquid level detection is performed using the second liquid level detection circuit. As a result, the saturated gas refrigerant is taken out under a wide range of temperature conditions by using either the first liquid level detection circuit or the second liquid level detection circuit without being influenced by the outside air temperature. From the temperature difference from the case where the saturated liquid refrigerant is taken out, it is possible to detect that the liquid refrigerant of the predetermined liquid level has accumulated in the receiver, and to detect the refrigerant filling amount with high accuracy. Therefore, it is possible to fill the optimum amount of refrigerant with no excess or deficiency with respect to the air conditioner.
 本発明の第5の態様にかかる空気調和機の冷媒量検出方法は、上述の空気調和機の冷媒量検出方法において、冷媒充填運転時、冷房定格程度の温度条件下では、前記液面検出回路のみを使用し、低外気温条件下では、前記液面検出回路および前記ホットガスバイパス回路の双方を使用して液面検出を行うことを特徴とする。 The refrigerant quantity detection method for an air conditioner according to a fifth aspect of the present invention is the above-described refrigerant quantity detection method for an air conditioner, wherein the liquid level detection circuit is used in a refrigerant charging operation under a temperature condition of about a cooling rating. The liquid level detection is performed using both the liquid level detection circuit and the hot gas bypass circuit under a low outside air temperature condition.
 前記第5の態様によれば、上記の空気調和機において、冷媒充填運転時、冷房定格程度の温度条件下では、液面検出回路のみを使用し、低外気温条件下では、液面検出回路およびホットガスバイパス回路の双方を使用して液面検出を行うようにしている。その結果、外気温に左右されることなく、液面検出回路または液面検出回路およびホットガスバイパス回路のいずれかを使用することにより、広範囲にわたる温度条件下において、飽和ガス冷媒が取出された場合と飽和液冷媒が取出された場合との温度差から、レシーバ内に所定液面の液冷媒が溜まったことを検出し、冷媒充填量を高精度で検出することができる。従って、空気調和機に対して過不足のない最適量の冷媒を充填することができる。 According to the fifth aspect, in the air conditioner described above, only the liquid level detection circuit is used under the temperature condition of the cooling rating during the refrigerant charging operation, and the liquid level detection circuit is used under the low outside air temperature condition. And the hot gas bypass circuit are used to detect the liquid level. As a result, when saturated gas refrigerant is taken out under a wide range of temperature conditions by using either the liquid level detection circuit or the liquid level detection circuit and the hot gas bypass circuit, regardless of the outside air temperature. And when the saturated liquid refrigerant is taken out, it can be detected that the liquid refrigerant of a predetermined liquid level has accumulated in the receiver, and the refrigerant filling amount can be detected with high accuracy. Therefore, it is possible to fill the optimum amount of refrigerant with no excess or deficiency with respect to the air conditioner.
 本発明の空気調和機および空気調和機の冷媒量検出方法によると、冷房定格程度の温度条件下では、レシーバからの冷媒を第1液面検出回路に流し込むことにより、レシーバから飽和ガス冷媒が取出された場合と、飽和液冷媒が取出された場合とにおいて、それぞれ減圧後の冷媒温度を検出し、その温度差からレシーバ内に所定液面の液冷媒が溜まったことを確実に検出することができる。一方、低外気温条件下では、レシーバから取出された飽和ガス冷媒を、第2液面検出回路を介して過冷却回路に流し込むことにより、過冷却熱交換器で液冷媒と熱交換させて加熱し、過熱度を十分大きくできるため、飽和液冷媒が取出された場合との温度差からレシーバ内に所定液面の液冷媒が溜まったことを確実に検出することができる。これによって、外気温による高圧の変動等に左右されることなく、広範囲な温度条件下において、上記温度差を十分に確保して高精度で冷媒充填量を検出することができ、過不足のない最適量の冷媒を充填し、空気調和機を安定して運転することが可能となる。また、過冷却回路を利用して冷媒を加熱できるため、第1液面検出回路側に特別に加熱手段を設ける必要がなく、構成を簡素化することができる。 According to the air conditioner and the refrigerant amount detection method of the air conditioner of the present invention, the saturated gas refrigerant is taken out from the receiver by flowing the refrigerant from the receiver into the first liquid level detection circuit under a temperature condition of about the cooling rating. And when the saturated liquid refrigerant is taken out, it is possible to detect the refrigerant temperature after depressurization and reliably detect that the liquid refrigerant of a predetermined liquid level has accumulated in the receiver from the temperature difference. it can. On the other hand, under a low outside air temperature condition, the saturated gas refrigerant taken out from the receiver flows into the supercooling circuit via the second liquid level detection circuit, so that heat is exchanged with the liquid refrigerant in the supercooling heat exchanger. In addition, since the degree of superheat can be sufficiently increased, it is possible to reliably detect that the liquid refrigerant of a predetermined liquid level has accumulated in the receiver from the temperature difference from the case where the saturated liquid refrigerant is taken out. As a result, the refrigerant charge amount can be detected with high accuracy by ensuring a sufficient temperature difference under a wide range of temperature conditions without being affected by fluctuations in high pressure due to the outside air temperature, and there is no excess or deficiency. It is possible to fill the optimal amount of refrigerant and to stably operate the air conditioner. Further, since the refrigerant can be heated using the supercooling circuit, it is not necessary to provide a heating means specially on the first liquid level detection circuit side, and the configuration can be simplified.
 また、本発明の空気調和機および空気調和機の冷媒量検出方法によると、冷房定格程度の温度条件下では、レシーバ内から液面検出回路に飽和状態のガス冷媒が取出された場合と、飽和液冷媒が取出された場合とにおいて、それぞれ減圧後の冷媒温度を検出し、その温度差からレシーバ内に所定レベルの液冷媒が溜まったことを検出することができる。一方、低外気温条件下では、レシーバから取出された飽和ガス冷媒に対してホットガスバイパス回路を経て導入されたホットガスを混合することにより加熱し、過熱度を十分大きくできるため、飽和液冷媒が取出された場合との温度差からレシーバ内に所定液面の液冷媒が溜まったことを検出することができる。従って、外気温による高圧の変動等にも左右されることなく、広範囲な温度条件下において、上記温度差を十分に確保して高精度で冷媒充填量を検出することができ、過不足のない最適量の冷媒を充填し、空気調和機を安定して運転することが可能となる。 Further, according to the air conditioner and the air conditioner refrigerant amount detection method of the present invention, under the temperature condition of the cooling rating, when the saturated gas refrigerant is taken out from the receiver to the liquid level detection circuit, When the liquid refrigerant is taken out, it is possible to detect the refrigerant temperature after depressurization and to detect that a predetermined level of liquid refrigerant has accumulated in the receiver from the temperature difference. On the other hand, under low outside air temperature conditions, the saturated gas refrigerant taken out from the receiver can be heated by mixing the hot gas introduced through the hot gas bypass circuit, and the degree of superheat can be sufficiently increased. It is possible to detect that the liquid refrigerant of the predetermined liquid level has accumulated in the receiver from the temperature difference from when the is taken out. Therefore, the refrigerant charge amount can be detected with high accuracy by sufficiently ensuring the temperature difference under a wide range of temperature conditions without being affected by fluctuations in high pressure due to the outside air temperature, and there is no excess or deficiency. It is possible to fill the optimal amount of refrigerant and to stably operate the air conditioner.
本発明の第1実施形態にかかる空気調和機の冷媒回路図である。It is a refrigerant circuit figure of the air conditioner concerning a 1st embodiment of the present invention. 図1に示す空気調和機において、高温時に第1液面検出回路を経て飽和ガス冷媒がバイパスされた場合の圧力-エンタルピ線図である。FIG. 2 is a pressure-enthalpy diagram when saturated gas refrigerant is bypassed through a first liquid level detection circuit at a high temperature in the air conditioner shown in FIG. 1. 図1に示す空気調和機において、高温時に第1液面検出回路を経て飽和液冷媒がバイパスされた場合の圧力-エンタルピ線図である。FIG. 2 is a pressure-enthalpy diagram when saturated liquid refrigerant is bypassed through a first liquid level detection circuit at a high temperature in the air conditioner shown in FIG. 1. 図1に示す空気調和機において、低温時に第1液面検出回路を経て飽和ガス冷媒がバイパスされた場合の圧力-エンタルピ線図である。FIG. 2 is a pressure-enthalpy diagram when the saturated gas refrigerant is bypassed through the first liquid level detection circuit at a low temperature in the air conditioner shown in FIG. 1. 図1に示す空気調和機において、低温時に第2液面検出回路を経て飽和ガス冷媒がバイパスされた場合の圧力-エンタルピ線図である。FIG. 2 is a pressure-enthalpy diagram when the saturated gas refrigerant is bypassed through the second liquid level detection circuit at a low temperature in the air conditioner shown in FIG. 1. 本発明の第2実施形態にかかる空気調和機の(一部を省略した)冷媒回路図である。It is a refrigerant circuit diagram (a part of which is omitted) of an air conditioner according to a second embodiment of the present invention. 図6に示す空気調和機において、低温時に液面検出回路およびホットガスバイパス回路を経て飽和ガス冷媒とホットガスとの混合冷媒がバイパスされた場合の圧力-エンタルピ線図である。7 is a pressure-enthalpy diagram when a mixed refrigerant of saturated gas refrigerant and hot gas is bypassed through a liquid level detection circuit and a hot gas bypass circuit at a low temperature in the air conditioner shown in FIG. 図6に示す空気調和機において、低温時に液面検出回路およびホットガスバイパス回路を経て飽和液冷媒とホットガスとの混合冷媒がバイパスされた場合の圧力-エンタルピ線図である。7 is a pressure-enthalpy diagram when a mixed refrigerant of saturated liquid refrigerant and hot gas is bypassed through a liquid level detection circuit and a hot gas bypass circuit at a low temperature in the air conditioner shown in FIG.
 以下に、本発明にかかる実施形態について、図面を参照して説明する。
[第1実施形態]
 以下、本発明の第1実施形態について、図1ないし図5を用いて説明する。
 図1には、本発明の第1実施形態にかかる空気調和機の冷媒回路図が示されている。
 空気調和機1は、ビル等の空調に適用されるマルチタイプの空気調和機であり、室外機2と、互いに並列に接続される複数台の室内機3(図1には、1台だけ図示されている。)とから構成されている。
Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 5.
FIG. 1 shows a refrigerant circuit diagram of an air conditioner according to the first embodiment of the present invention.
The air conditioner 1 is a multi-type air conditioner that is applied to air conditioning of buildings and the like, and includes an outdoor unit 2 and a plurality of indoor units 3 connected in parallel to each other (FIG. 1 shows only one unit). It is composed of).
 室外機2の内部には、冷媒を圧縮する圧縮機10、冷媒の循環方向を切換える四方切換弁11、外気と冷媒とを熱交換する室外熱交換器12、室外熱交換器12に外気を通風する室外ファン13、暖房用電動膨張弁(暖房用膨張弁)14、凝縮された液冷媒を溜めるレシーバ15等が配設されており、圧縮機10、四方切換弁11、室外熱交換器12、暖房用電動膨張弁14およびレシーバ15が順次冷媒配管16を介して接続されることによって、室外側冷媒回路17が構成されている。 Inside the outdoor unit 2, a compressor 10 that compresses the refrigerant, a four-way switching valve 11 that switches the circulation direction of the refrigerant, an outdoor heat exchanger 12 that exchanges heat between the outside air and the refrigerant, and the outside air are passed through the outdoor heat exchanger 12. An outdoor fan 13 for heating, an electric expansion valve for heating (heating expansion valve) 14, a receiver 15 for accumulating condensed liquid refrigerant, and the like are disposed, and a compressor 10, a four-way switching valve 11, an outdoor heat exchanger 12, The outdoor refrigerant circuit 17 is configured by sequentially connecting the heating electric expansion valve 14 and the receiver 15 via the refrigerant pipe 16.
 この室外側冷媒回路17には、液冷媒の一部を分流し、この液冷媒を過冷却用膨張弁(減圧機構)18で減圧した後、過冷却熱交換器19を経て圧縮機10の吸入側に戻すことにより、過冷却熱交換器19において液冷媒に過冷却を付与する過冷却回路20が設けられている。 A part of the liquid refrigerant is divided into the outdoor refrigerant circuit 17, and the liquid refrigerant is decompressed by the supercooling expansion valve (decompression mechanism) 18, and then sucked into the compressor 10 through the supercooling heat exchanger 19. By returning to the side, a supercooling circuit 20 for providing supercooling to the liquid refrigerant in the supercooling heat exchanger 19 is provided.
 室内機3の内部には、室内熱交換器30、室内熱交換器30を通して室内空気を循環させる室内ファン31、冷房用電動膨張弁(冷房用膨張弁)32等が配設されており、この室内機3と室外機2とがガス冷媒配管33および液冷媒配管34を介して接続されることにより、閉サイクルの冷媒回路35が構成されるようになっている。複数台の室内機3は、ガス冷媒配管33および液冷媒配管34から分岐されたガス冷媒配管33および液冷媒配管34を介して互いに並列に接続されるようになっている。 Inside the indoor unit 3, an indoor heat exchanger 30, an indoor fan 31 that circulates indoor air through the indoor heat exchanger 30, an electric expansion valve for cooling (an expansion valve for cooling) 32, and the like are disposed. The indoor unit 3 and the outdoor unit 2 are connected through a gas refrigerant pipe 33 and a liquid refrigerant pipe 34, whereby a closed cycle refrigerant circuit 35 is configured. The plurality of indoor units 3 are connected in parallel to each other via a gas refrigerant pipe 33 and a liquid refrigerant pipe 34 branched from the gas refrigerant pipe 33 and the liquid refrigerant pipe 34.
 空気調和機1は、圧縮機10から吐出された冷媒を、四方切換弁11を介して室外熱交換器12側に循環させ、レシーバ15、過冷却熱交換器19、冷房用電動膨張弁32、室内熱交換器30、四方切換弁11および圧縮機10の順に時計方向に循環させることによって、室外熱交換器12を凝縮器、室内熱交換器30を蒸発器として機能させ、冷房運転できるようになっている。この間、過冷却熱交換器19において、液冷媒と過冷却回路20に分流され、過冷却用膨張弁(減圧機構)18で減圧された冷媒とを熱交換させて液冷媒に過冷却を与えることにより、冷房能力を向上させることができる。 The air conditioner 1 circulates the refrigerant discharged from the compressor 10 to the outdoor heat exchanger 12 side via the four-way switching valve 11, and receives the receiver 15, the supercooling heat exchanger 19, the cooling electric expansion valve 32, By circulating the indoor heat exchanger 30, the four-way switching valve 11 and the compressor 10 in the clockwise direction, the outdoor heat exchanger 12 functions as a condenser and the indoor heat exchanger 30 functions as an evaporator so that the cooling operation can be performed. It has become. During this time, in the supercooling heat exchanger 19, heat is exchanged between the liquid refrigerant and the refrigerant that is diverted to the supercooling circuit 20 and decompressed by the supercooling expansion valve (decompression mechanism) 18, thereby supercooling the liquid refrigerant. Thus, the cooling capacity can be improved.
 一方、圧縮機10から吐出された冷媒を、四方切換弁11を介して室内熱交換器30側に循環させ、過冷却熱交換器19、レシーバ15、暖房用電動膨張弁14、室外熱交換器12、四方切換弁11および圧縮機10の順に反時計方向に循環させることによって、室内熱交換器30を凝縮器、室外熱交換器12を蒸発器として機能させ、暖房運転できるようになっている。 On the other hand, the refrigerant discharged from the compressor 10 is circulated to the indoor heat exchanger 30 side via the four-way switching valve 11, and the supercooling heat exchanger 19, the receiver 15, the heating electric expansion valve 14, the outdoor heat exchanger. 12, the four-way switching valve 11 and the compressor 10 are circulated in the counterclockwise direction so that the indoor heat exchanger 30 functions as a condenser and the outdoor heat exchanger 12 functions as an evaporator, so that a heating operation can be performed. .
 上記空気調和機1において、室外機2と室内機3との間を接続するガス冷媒配管33および液冷媒配管34の配管長さは、空気調和機1が据付けられる環境によって様々変化する。このため、予め室外機2に所定量の冷媒を充填しておき、現地において空気調和機1を据付けした後、試運転するときに、室外機2と室内機3との間を接続する配管長さや室内機3の接続台数等に応じて不足量の冷媒を追加充填しなければならない。この冷媒を追加充填する際、現地での工事レベルに依存することなく、常に適正な量の冷媒を充填できるようにするため、以下の第1液面検出回路40および第2液面検出回路45並びに冷媒量検出部48が組み込まれている。 In the air conditioner 1, the lengths of the gas refrigerant pipe 33 and the liquid refrigerant pipe 34 connecting the outdoor unit 2 and the indoor unit 3 vary depending on the environment in which the air conditioner 1 is installed. For this reason, when the outdoor unit 2 is preliminarily filled with a predetermined amount of refrigerant and the air conditioner 1 is installed in the field, the length of the pipe connecting the outdoor unit 2 and the indoor unit 3 when the test operation is performed Insufficient amount of refrigerant must be charged according to the number of indoor units 3 connected. When the refrigerant is additionally charged, the following first liquid level detection circuit 40 and second liquid level detection circuit 45 described below are used so that an appropriate amount of refrigerant can be always charged without depending on the construction level at the site. In addition, a refrigerant amount detection unit 48 is incorporated.
 第1液面検出回路40は、レシーバ15内の所定高さ位置から圧縮機10の吸入側に冷媒を取出すことができるバイパス回路41と、このバイパス回路41中に設けられているキャピラリチューブ、膨張弁等からなる減圧機構42および電磁開閉弁43とか構成されており、バイパス回路41は、過冷却回路20が圧縮機10の吸入配管と接続される接続部近くで過冷却回路20に接続合流されている。このバイパス回路41の接続合流部より圧縮機10の吸入配管側の位置に、バイパス回路41および過冷却回路20内を流れる減圧機構42または減圧機構18で減圧された冷媒温度を検出するサーミスタ等の温度センサ(温度検出部)44が設置されている。 The first liquid level detection circuit 40 includes a bypass circuit 41 that can take out a refrigerant from a predetermined height position in the receiver 15 to the suction side of the compressor 10, a capillary tube provided in the bypass circuit 41, an expansion The bypass circuit 41 is connected and joined to the supercooling circuit 20 near the connection portion where the supercooling circuit 20 is connected to the suction pipe of the compressor 10. ing. A thermistor or the like that detects the temperature of the refrigerant depressurized by the depressurization mechanism 42 or the depressurization mechanism 18 that flows through the bypass circuit 41 and the subcooling circuit 20 at a position closer to the suction pipe side of the compressor 10 than the connection junction of the bypass circuit 41 A temperature sensor (temperature detection unit) 44 is installed.
 第2液面検出回路45は、第1液面検出回路40を構成しているバイパス回路41中の減圧機構42の手前位置から分岐され、過冷却回路20の過冷却用膨張弁(減圧機構)18の入口側に接続された回路に電磁開閉弁46を設けた構成とされている。この第2液面検出回路45は、冷媒充填運転時に、レシーバ15から取出された冷媒を過冷却回路20中の過冷却用膨張弁(減圧機構)18および過冷却熱交換器19を経て圧縮機10の吸入側に戻す回路を構成するものである。この際、過冷却回路20に液冷媒が分流されるのを止めるため、過冷却回路20の分岐部近くに電磁開閉弁47が設けられている。 The second liquid level detection circuit 45 is branched from a position before the decompression mechanism 42 in the bypass circuit 41 constituting the first liquid level detection circuit 40, and is a subcooling expansion valve (decompression mechanism) of the supercooling circuit 20. The circuit connected to the 18 inlet side is provided with an electromagnetic on-off valve 46. The second liquid level detection circuit 45 passes through the supercooling expansion valve (decompression mechanism) 18 and the supercooling heat exchanger 19 in the supercooling circuit 20 for the refrigerant taken out from the receiver 15 during the refrigerant charging operation. 10 is a circuit that returns to the suction side. At this time, an electromagnetic on-off valve 47 is provided near the branch portion of the supercooling circuit 20 in order to stop the liquid refrigerant from being diverted to the supercooling circuit 20.
 冷媒量検出部48は、温度センサ44の検出温度に基づいて冷媒が適正量充填されたか否かを判定するためのものであり、冷媒充填運転中に、レシーバ15内に液冷媒が溜まり、その液面レベルが、バイパス回路31が開口する高さ位置に達し、第1液面検出回路40または第2液面検出回路45に飽和状態の液冷媒が取出された場合における温度センサ44からの検出温度と、液冷媒が所定高さ位置に到達するまで間、第1液面検出回路40または第2液面検出回路45に飽和状態のガス冷媒が取出されていた場合における温度センサ44からの検出温度との温度差に基づいて、冷媒が適正量充填されたか否かを判定できる構成とされている。 The refrigerant amount detector 48 is for determining whether or not an appropriate amount of refrigerant has been charged based on the temperature detected by the temperature sensor 44. During the refrigerant charging operation, liquid refrigerant accumulates in the receiver 15, Detection from the temperature sensor 44 when the liquid level reaches the height position where the bypass circuit 31 is opened and the saturated liquid refrigerant is taken out by the first liquid level detection circuit 40 or the second liquid level detection circuit 45. Detection from the temperature sensor 44 when the saturated gas refrigerant is taken out by the first liquid level detection circuit 40 or the second liquid level detection circuit 45 until the temperature and the liquid refrigerant reach a predetermined height position. Based on the temperature difference from the temperature, it is possible to determine whether or not an appropriate amount of refrigerant has been charged.
 冷媒量検出部48は、冷媒充填運転時、過冷却回路20に設けられている電磁開閉弁47を閉とするとともに、外気温や高圧側圧力等に応じて第1液面検出回路40または第2液面検出回路45の何れの回路を使って液面検出を行うのかを決定する際、電磁開閉弁43,46を開閉制御する機能を担っている。すなわち、第1液面検出回路40を使う場合は、電磁開閉弁43を開、電磁開閉弁46を閉とし、第2液面検出回路45を使う場合は、電磁開閉弁43を閉、電磁開閉弁46を開とするようになっている。 The refrigerant amount detection unit 48 closes the electromagnetic on-off valve 47 provided in the supercooling circuit 20 during the refrigerant charging operation, and the first liquid level detection circuit 40 or the first level according to the outside air temperature, the high pressure side pressure, or the like. When deciding which of the two liquid level detection circuits 45 is to be used for liquid level detection, it has a function of controlling opening and closing of the electromagnetic on-off valves 43 and 46. That is, when using the first liquid level detection circuit 40, the electromagnetic switching valve 43 is opened and the electromagnetic switching valve 46 is closed. When using the second liquid level detection circuit 45, the electromagnetic switching valve 43 is closed and the electromagnetic switching valve is closed. The valve 46 is opened.
 次に、冷媒充填運転と冷媒充填量の検出方法について、図2ないし図5を参照して更に詳しく説明する。
 冷媒充填運転は、冷媒回路35を冷房サイクルとして運転される。この際、室外熱交換器12での凝縮圧力が所定値となるように室外ファン13が制御されるとともに、室内熱交換器30の出口で冷媒に所定の過熱度が付与されるように冷房用電動膨張弁32の開度が制御される。これにより、液冷媒配管34内に所定密度の液冷媒を満たした状態として冷媒回路35に冷媒を充填することができる。
Next, the refrigerant filling operation and the refrigerant filling amount detection method will be described in more detail with reference to FIGS.
In the refrigerant charging operation, the refrigerant circuit 35 is operated as a cooling cycle. At this time, the outdoor fan 13 is controlled so that the condensation pressure in the outdoor heat exchanger 12 becomes a predetermined value, and at the outlet of the indoor heat exchanger 30, a predetermined superheat degree is given to the refrigerant. The opening degree of the electric expansion valve 32 is controlled. Thereby, the refrigerant can be filled in the refrigerant circuit 35 in a state where the liquid refrigerant pipe 34 is filled with the liquid refrigerant having a predetermined density.
 このとき、過冷却回路20中の電磁開閉弁47は閉とされるとともに、例えば外気温が冷房定格程度の高温時には、電磁開閉弁43が開、電磁開閉弁46が閉とされ、低外気温時には、電磁開閉弁43が閉、電磁開閉弁46が開とされる。この状態で運転を継続すると、冷媒回路35中の冷媒循環量が徐々に増大され、レシーバ15内の冷媒の液面が徐々に上昇してくる。これは、室内熱交換器30での冷媒の蒸発量と室外熱交換器12での冷媒の凝縮量がバランスしているためであり、外部から充填される冷媒量の分だけ、レシーバ15内に凝縮した液冷媒が徐々に溜まってくる。 At this time, the electromagnetic on-off valve 47 in the supercooling circuit 20 is closed and, for example, when the outside air temperature is high, such as a cooling rating, the electromagnetic on-off valve 43 is opened, the electromagnetic on-off valve 46 is closed, and the low outside air temperature is low. Sometimes, the electromagnetic on-off valve 43 is closed and the electromagnetic on-off valve 46 is opened. When the operation is continued in this state, the refrigerant circulation amount in the refrigerant circuit 35 is gradually increased, and the liquid level of the refrigerant in the receiver 15 gradually increases. This is because the evaporation amount of the refrigerant in the indoor heat exchanger 30 and the condensation amount of the refrigerant in the outdoor heat exchanger 12 are balanced, and the amount of the refrigerant charged from the outside is in the receiver 15. The condensed liquid refrigerant gradually accumulates.
 ここで、外気温が冷房定格程度の高温時で電磁開閉弁43が開、電磁開閉弁46が閉とされている場合、バイパス回路41が開口されている高さ位置までレシーバ15内に液冷媒が溜まるまでの間は、レシーバ15内の飽和ガス冷媒が第1液面検出回路40に流れることになり、バイパス回路41が開口されている高さ位置まで液冷媒の液面レベルが上昇すると、飽和状態の液冷媒が第1液面検出回路40に流れることになる。外気温が高く、高圧が上昇する場合には、圧縮機10の回転数、室外ファン13の回転数等を制御して高圧を低下させるようにすればよい。 Here, when the electromagnetic on-off valve 43 is open and the electromagnetic on-off valve 46 is closed when the outside air temperature is high, such as the cooling rating, the liquid refrigerant is placed in the receiver 15 up to a height position where the bypass circuit 41 is open. Until the gas level is accumulated, the saturated gas refrigerant in the receiver 15 flows to the first liquid level detection circuit 40, and when the liquid level of the liquid refrigerant rises to a height position where the bypass circuit 41 is opened, The saturated liquid refrigerant flows into the first liquid level detection circuit 40. When the outside air temperature is high and the high pressure rises, the high pressure may be lowered by controlling the rotation speed of the compressor 10, the rotation speed of the outdoor fan 13, and the like.
 この飽和ガス冷媒または飽和液冷媒は、それぞれ減圧機構43によって低圧状態に減圧され、温度降下する。この冷媒の温度を温度センサ44で検出することにより、飽和ガス冷媒の状態から温度降下された場合と、飽和液冷媒の状態から温度降下された場合との温度差を見て、冷媒量検出部48がレシーバ15内に所定液面の液冷媒が溜まったことを検出し、所要量の冷媒が充填されたと判定するようにしており、この時点で冷媒の充填運転が終了されることになる。 The saturated gas refrigerant or saturated liquid refrigerant is decompressed to a low pressure state by the decompression mechanism 43, and the temperature drops. By detecting the temperature of the refrigerant with the temperature sensor 44, the refrigerant amount detection unit looks at the temperature difference between the temperature drop from the saturated gas refrigerant state and the temperature drop from the saturated liquid refrigerant state. 48 detects that the liquid refrigerant of a predetermined liquid level has accumulated in the receiver 15, and determines that the required amount of refrigerant has been filled. At this point, the refrigerant filling operation is terminated.
 冷媒が適正量充填されたか否かを精度よく検出するためには、上記温度差が十分に確保されることが望ましい。上記において、レシーバ15から第1液面検出回路40に飽和ガス冷媒が取出されている場合は、図2に示されるように、レシーバ15内の圧力が2MPa付近(冷媒がR410Aの場合)であれば、減圧機構43で減圧されてA点に温度降下し、一定の大きさの過熱度SHを確保することができる。一方、図3に示されるように、飽和液冷媒が取出され、減圧機構43で減圧されて蒸発することによりB点に温度降下した冷媒の過熱度は0℃であり、一定値以上の温度差を確保できることから、適正量の冷媒が充填されたことを確実に検出することができる。 In order to accurately detect whether or not an appropriate amount of refrigerant has been charged, it is desirable that the temperature difference is sufficiently secured. In the above, when the saturated gas refrigerant is taken out from the receiver 15 to the first liquid level detection circuit 40, as shown in FIG. 2, the pressure in the receiver 15 is around 2 MPa (when the refrigerant is R410A). For example, the pressure is reduced by the pressure reducing mechanism 43, the temperature is lowered to the point A, and a certain degree of superheat SH can be secured. On the other hand, as shown in FIG. 3, when the saturated liquid refrigerant is taken out, depressurized by the depressurization mechanism 43 and evaporated, the degree of superheat of the refrigerant having dropped to the point B is 0 ° C., and the temperature difference exceeds a certain value. Therefore, it is possible to reliably detect that an appropriate amount of refrigerant has been charged.
 しかし、低外気温時は、高圧が低下し、レシーバ15内の圧力も低下するため、図4に示されるように、飽和ガス冷媒が取出された場合、減圧機構43で減圧されてC点に温度降下されることから、殆んど過熱度SHを確保することができない。従って、飽和液冷媒が取出され、減圧機構43で減圧されて温度降下することにより過熱度が0℃となる場合に対して、十分に温度差を確保することができず、これが誤判定の要因となる。特に、過熱度が2~3℃以下の場合は、誤判定される可能性が高くなる。 However, when the outside air temperature is low, the high pressure is reduced and the pressure in the receiver 15 is also reduced. Therefore, when the saturated gas refrigerant is taken out, as shown in FIG. Since the temperature is lowered, the degree of superheat SH can hardly be secured. Accordingly, a sufficient temperature difference cannot be secured with respect to the case where the degree of superheat becomes 0 ° C. due to the saturated liquid refrigerant being taken out and depressurized by the depressurization mechanism 43 to drop in temperature. It becomes. In particular, when the degree of superheat is 2 to 3 ° C. or less, there is a high possibility of erroneous determination.
 そこで、本実施形態では、高圧が低下する低外気温時で、圧力-エンタルピ線図上の飽和ガス線の傾きが右肩上がりのときには、電磁開閉弁43を閉、電磁開閉弁46を開として液面検知回路を第2液面検出回路45に切換えることにより、レシーバ15から取出された冷媒を、第2液面検出回路45を介して過冷却回路20に流すようにしている。このように、第2液面検出回路45を介して過冷却回路20に取出された冷媒は、過冷却用膨張弁(減圧機構)18により減圧された後、過冷却熱交換器19で液冷媒と熱交換されて加熱、蒸発され、圧縮機10の吸入側に戻されることになる。 Therefore, in this embodiment, when the slope of the saturated gas line on the pressure-enthalpy diagram rises to the right at the low outside air temperature at which the high pressure decreases, the electromagnetic on-off valve 43 is closed and the electromagnetic on-off valve 46 is opened. By switching the liquid level detection circuit to the second liquid level detection circuit 45, the refrigerant taken out from the receiver 15 is allowed to flow to the supercooling circuit 20 via the second liquid level detection circuit 45. As described above, the refrigerant taken out to the supercooling circuit 20 via the second liquid level detection circuit 45 is decompressed by the supercooling expansion valve (decompression mechanism) 18, and then is cooled by the supercooling heat exchanger 19. The heat is exchanged and heated, evaporated, and returned to the suction side of the compressor 10.
 この過冷却回路20を経た冷媒の温度を温度センサ44で検出することによって、飽和ガス冷媒が取出された場合と飽和液冷媒が取出された場合とにおいて、一定値以上の温度差を確保することができる。つまり、図5に示されるように、飽和液冷媒は、減圧機構18で減圧されて温度降下した後、過冷却熱交換器19で加熱、蒸発され、飽和ガス線上のD点で過熱度が0℃の冷媒となる。これに対して、飽和ガス冷媒は、減圧されてC点まで温度降下した後、過冷却熱交換器19で加熱されることによってE点まで過熱度SHが増大される。このため、温度差を十分確保でき、冷媒量検出部48により適正量の冷媒が充填されたことを確実に検出することができる。 By detecting the temperature of the refrigerant that has passed through the supercooling circuit 20 with the temperature sensor 44, a temperature difference of a certain value or more is secured between when the saturated gas refrigerant is taken out and when the saturated liquid refrigerant is taken out. Can do. That is, as shown in FIG. 5, the saturated liquid refrigerant is depressurized by the depressurization mechanism 18 and dropped in temperature, then heated and evaporated by the supercooling heat exchanger 19, and the superheat degree is 0 at point D on the saturated gas line. It becomes a refrigerant at ℃. On the other hand, the saturated gas refrigerant is depressurized and drops in temperature to the point C, and then heated by the supercooling heat exchanger 19, whereby the superheat degree SH is increased to the point E. For this reason, a sufficient temperature difference can be ensured, and the refrigerant amount detection unit 48 can reliably detect that an appropriate amount of refrigerant has been charged.
 このように、低外気温時で高圧側の圧力が確保できないような条件下でも、レシーバ15から取出された飽和ガス冷媒を、第2液面検出回路45を介して過冷却回路20に流し込むことにより、過冷却熱交換器19で液冷媒と熱交換させて加熱し、過熱度を十分大きくできるため、飽和液冷媒が取出された場合との温度差からレシーバ15内に所定液面の液冷媒が溜まったことを確実に検出することができる。
 従って、外気温による高圧の変動等に左右されることなく、広範囲に亘る温度条件下において、飽和ガス冷媒と飽和液冷媒との温度差を十分に確保して高精度で冷媒充填量を検出することができ、過不足のない最適量の冷媒を充填し、空気調和機1を安定して運転することが可能となる。また、過冷却回路20を利用して冷媒を加熱できるため、第1液面検出回路40側に特別に加熱手段を設ける必要がなく、構成を簡素化することができる。
As described above, the saturated gas refrigerant taken out from the receiver 15 is allowed to flow into the supercooling circuit 20 via the second liquid level detection circuit 45 even under conditions where the pressure on the high pressure side cannot be secured at low outside air temperature. Therefore, the supercooling heat exchanger 19 heats the liquid refrigerant for heating, and the degree of superheat can be sufficiently increased. Therefore, the liquid refrigerant of a predetermined liquid level is introduced into the receiver 15 from the temperature difference from when the saturated liquid refrigerant is taken out. Can be reliably detected.
Therefore, the refrigerant charge amount is detected with high accuracy by ensuring a sufficient temperature difference between the saturated gas refrigerant and the saturated liquid refrigerant under a wide range of temperature conditions without being influenced by high pressure fluctuations caused by the outside air temperature. It is possible to fill the optimal amount of refrigerant without excess and deficiency, and to operate the air conditioner 1 stably. Further, since the refrigerant can be heated using the supercooling circuit 20, it is not necessary to provide a heating means specially on the first liquid level detection circuit 40 side, and the configuration can be simplified.
 さらに、本実施形態では、過冷却回路20の冷媒回路35からの分岐部付近に、冷媒充填運転時に閉とされ、通常の冷暖房運転時には開とされる電磁開閉弁47が設けられているため、電磁開閉弁47の開閉操作のみによって簡単に冷媒充填運転と通常の冷暖房運転との切換えを行うことができる。従って、過冷却回路20を、通常の冷暖房運転時の能力向上以外に、冷媒充填運転時の液面検出回路として併用し、冷媒充填量の検出精度の向上に資することができる。また、温度センサ44として、過冷却回路20に設けられている既存の温度センサを共用化することができるため、温度センサを節減することができる。 Furthermore, in the present embodiment, an electromagnetic on-off valve 47 that is closed during the refrigerant charging operation and opened during the normal cooling / heating operation is provided near the branch portion from the refrigerant circuit 35 of the supercooling circuit 20. Switching between the refrigerant charging operation and the normal air conditioning operation can be easily performed only by opening / closing the electromagnetic opening / closing valve 47. Therefore, the supercooling circuit 20 can be used in combination as a liquid level detection circuit during the refrigerant charging operation, in addition to improving the capability during the normal cooling / heating operation, and can contribute to an improvement in the detection accuracy of the refrigerant filling amount. Moreover, since the existing temperature sensor provided in the supercooling circuit 20 can be shared as the temperature sensor 44, a temperature sensor can be saved.
[第2実施形態]
 次に、本発明の第2実施形態について、図6ないし図8を用いて説明する。
 本実施形態は、上記した第1実施形態に対して、第2液面検出回路45に代え、ホットガスバイパス回路50を設けた構成としている点が異なる。その他の点については、第1実施形態と同様であるので説明は省略する。
 本実施形態では、図6に示されるように、上記第1液面検出回路40と同様、レシーバ15内の所定高さ位置と圧縮機10の吸入側との間を接続するバイパス回路41にキャピラリチューブ、膨張弁等からなる減圧機構42および電磁開閉弁43を介装した液面検出回路40と、圧縮機10の吐出側から吸入側にホットガスの一部を導入可能な電磁開閉弁51およびキャピラリチューブ、膨張弁等からなる減圧機構52を備えたホットガスバイパス回路50と、液面検出回路40を経た冷媒または該冷媒とホットガスバイパス回路50より導入されたホットガスとの混合冷媒の温度を検出する温度センサ53と、を備えた構成とされている。
[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS.
The present embodiment differs from the first embodiment described above in that a hot gas bypass circuit 50 is provided instead of the second liquid level detection circuit 45. Since other points are the same as those in the first embodiment, description thereof will be omitted.
In the present embodiment, as shown in FIG. 6, similarly to the first liquid level detection circuit 40, a capillary is connected to a bypass circuit 41 that connects a predetermined height position in the receiver 15 and the suction side of the compressor 10. A liquid level detection circuit 40 having a pressure reducing mechanism 42 and an electromagnetic opening / closing valve 43 including a tube, an expansion valve, etc., an electromagnetic opening / closing valve 51 capable of introducing a part of hot gas from the discharge side to the suction side of the compressor 10 Temperature of a hot gas bypass circuit 50 having a pressure reducing mechanism 52 including a capillary tube, an expansion valve, etc., and a refrigerant that has passed through the liquid level detection circuit 40 or a mixture of the refrigerant and hot gas introduced from the hot gas bypass circuit 50 And a temperature sensor 53 for detecting.
 本実施形態において、冷媒量検出部48は、上記第1実施形態と同様、温度センサ53からの検出値に基づいてレシーバ15内に所定液面の液冷媒が溜まったことを検出し、冷媒充填量を判定できるようになっている。また、冷媒量検出部48は、冷媒充填運転時、外気温や高圧側圧力等に応じて液面検出回路40のみを使うのか、ホットガスバイパス回路50を併用して液面検出を行うのかを決定する際、電磁開閉弁43,51を開閉制御する機能を担っている。すなわち、液面検出回路40のみを使う場合には、電磁開閉弁43を開、電磁開閉弁51を閉とし、液面検出回路40とホットガスバイパス回路50とを併用する場合には、電磁開閉弁43,51の双方を開とするようになっている。 In the present embodiment, similarly to the first embodiment, the refrigerant amount detection unit 48 detects that liquid refrigerant of a predetermined liquid level has accumulated in the receiver 15 based on the detection value from the temperature sensor 53, and fills the refrigerant. The amount can be determined. In addition, the refrigerant quantity detection unit 48 determines whether to use only the liquid level detection circuit 40 according to the outside air temperature, the high pressure side pressure, or the like during the refrigerant charging operation, or to perform the liquid level detection using the hot gas bypass circuit 50 together. When the determination is made, the electromagnetic on / off valves 43 and 51 are controlled to open / close. That is, when only the liquid level detection circuit 40 is used, the electromagnetic switching valve 43 is opened and the electromagnetic switching valve 51 is closed, and when the liquid level detection circuit 40 and the hot gas bypass circuit 50 are used together, the electromagnetic switching is performed. Both valves 43 and 51 are opened.
 このように、レシーバ15の所定高さ位置と圧縮機10の吸入側との間に減圧機構42および電磁開閉弁43を備えた液面検出回路40を設けるとともに、圧縮機10の吐出側と吸入側との間に、電磁開閉弁41および減圧機構42が介装されたホットガスバイパス回路50を設け、このホットガスバイパス回路50を介して圧縮機10から吐出されたホットガスの一部を吸入側に導入可能な構成とすることにより、外気温が冷房定格程度の高温時には、液面検出回路40のみを使用して上記第1実施形態と同様、レシーバ15から飽和ガス冷媒が取出された場合と、飽和液冷媒が取出された場合との間において、一定値以上の温度差を確保できることから、冷媒量検出部48により適正量の冷媒が充填されたことを確実に検出することができる。 As described above, the liquid level detection circuit 40 including the pressure reducing mechanism 42 and the electromagnetic opening / closing valve 43 is provided between the predetermined height position of the receiver 15 and the suction side of the compressor 10, and the discharge side and suction of the compressor 10 are provided. A hot gas bypass circuit 50 in which an electromagnetic on-off valve 41 and a pressure reducing mechanism 42 are interposed is provided between the compressor 10 and the hot gas discharged from the compressor 10 via the hot gas bypass circuit 50. In the case where the saturated gas refrigerant is taken out from the receiver 15 using only the liquid level detection circuit 40 when the outside air temperature is as high as the cooling rating, as in the first embodiment. And when the saturated liquid refrigerant is taken out, a temperature difference of a certain value or more can be ensured, so that the refrigerant amount detector 48 can reliably detect that the appropriate amount of refrigerant has been charged. Kill.
 低外気温時には、電磁開閉弁51を開き、ホットガスバイパス回路50を介して減圧機構52で減圧されたホットガスを圧縮機10の吸入側に導入することにより、このホットガスをレシーバ15から液面検出回路40に取出された冷媒と混合し、該冷媒を加熱することができる。このため、レシーバ15から液面検出回路40に取出された飽和ガス冷媒は、図7に示されるように、減圧されてF点に温度降下した後、G点に減圧されたホットガスと混合されて過熱度SHがH点まで上昇される。一方、レシーバ15から取出された飽和液冷媒は、図8に示されるように、減圧されて蒸発され、I点に温度降下した後、J点に減圧されたホットガスと混合されてK点とされても過熱度を確保することができない。従って、温度差を十分に確保することができ、冷媒量検出部48により適正量の冷媒が充填されたことを確実に検出することができる。 When the outside air temperature is low, the electromagnetic on-off valve 51 is opened, and hot gas decompressed by the decompression mechanism 52 is introduced to the suction side of the compressor 10 via the hot gas bypass circuit 50, so that the hot gas is discharged from the receiver 15. The refrigerant can be mixed with the refrigerant taken out by the surface detection circuit 40 and heated. For this reason, the saturated gas refrigerant taken out from the receiver 15 to the liquid level detection circuit 40 is mixed with hot gas decompressed to the point G after being decompressed and dropped to the point F as shown in FIG. Thus, the degree of superheat SH is raised to the H point. On the other hand, as shown in FIG. 8, the saturated liquid refrigerant taken out from the receiver 15 is depressurized and evaporated, drops in temperature to the I point, and then mixed with the hot gas depressurized to the J point to obtain the K point. However, the degree of superheat cannot be ensured. Therefore, a sufficient temperature difference can be ensured, and the refrigerant amount detection unit 48 can reliably detect that an appropriate amount of refrigerant has been charged.
 このため、低外気温条件下でも、液面検出回路40に取出された冷媒に対して、圧縮機10の吐出側からホットガスバイパス回路50を介して吸入側に導入されたホットガスを混合し加熱することにより、飽和ガス冷媒が取出された場合と飽和液冷媒とが取出された場合との温度差からレシーバ15内に所定液面の液冷媒が溜まったことを確実に検出することができる。従って、外気温による高圧の変動等に左右されることなく、広範囲の温度条件下において、飽和ガス冷媒と飽和液冷媒との温度差を十分に確保して高精度で冷媒充填量を検出することができ、過不足のない最適量の冷媒を充填し、空気調和機1を安定して運転することが可能となる。 For this reason, hot gas introduced from the discharge side of the compressor 10 to the suction side via the hot gas bypass circuit 50 is mixed with the refrigerant taken out by the liquid level detection circuit 40 even under a low outside air temperature condition. By heating, it is possible to reliably detect that the liquid refrigerant of a predetermined liquid level has accumulated in the receiver 15 from the temperature difference between when the saturated gas refrigerant is taken out and when the saturated liquid refrigerant is taken out. . Therefore, the refrigerant charging amount can be detected with high accuracy by ensuring a sufficient temperature difference between the saturated gas refrigerant and the saturated liquid refrigerant under a wide range of temperature conditions without being influenced by high pressure fluctuations caused by the outside air temperature. Therefore, the air conditioner 1 can be stably operated by filling an optimal amount of refrigerant without excess or deficiency.
 また、本実施形態では、液面検出回路40からの冷媒に対して、直接ホットガスを混合して冷媒を加熱するようにしているため、時間遅れなく温度検出でき、従って、冷媒充填量の検出精度をより高めることができる。更に、温度センサ53として、圧縮機10の吸入配管に設けられている既存の吸入温度センサを共用化することができるため、温度センサを節減することができる。 Further, in the present embodiment, the hot gas is directly mixed with the refrigerant from the liquid level detection circuit 40 to heat the refrigerant, so that the temperature can be detected without a time delay, and therefore the refrigerant charge amount is detected. The accuracy can be further increased. Furthermore, since the existing suction temperature sensor provided in the suction pipe of the compressor 10 can be shared as the temperature sensor 53, the temperature sensor can be saved.
 本発明は、上記実施形態にかかる発明に限定されるものではなく、その要旨を逸脱しない範囲において、適宜変形が可能である。例えば、上記第2実施形態では、過冷却回路20が省略されているが、過冷却回路20を備えた空気調和機1に第2実施形態にかかる発明を適用してもよいことはもちろんである。また、上記実施形態では、第1液面検出回路(液面検出回路)40のバイパス回路41がレシーバ15の上面から挿入接続された構成とされているが、バイパス回路41は、レシーバ15内の所定高さ位置に開口されるように接続されておればよく、従って、レシーバ15の側面あるいは下面から挿入して所定高さ位置に開口されるように接続してもよい。 The present invention is not limited to the invention according to the above-described embodiment, and can be modified as appropriate without departing from the scope of the invention. For example, although the supercooling circuit 20 is omitted in the second embodiment, the invention according to the second embodiment may be applied to the air conditioner 1 including the supercooling circuit 20. . In the above embodiment, the bypass circuit 41 of the first liquid level detection circuit (liquid level detection circuit) 40 is inserted and connected from the upper surface of the receiver 15. As long as it is connected so as to be opened at a predetermined height position, it may be inserted from the side surface or the lower surface of the receiver 15 so as to be opened at a predetermined height position.
1 空気調和機
2 室外機
3 室内機
10 圧縮機
12 室外熱交換器
14 暖房用電動膨張弁(暖房用膨張弁)
15 レシーバ
18 過冷却用膨張弁(減圧機構)
19 過冷却熱交換器
20 過冷却回路
30 室内熱交換器
32 冷房用電動膨張弁(冷房用膨張弁)
33 ガス冷媒配管
34 液冷媒配管
35 冷媒回路
40 第1液面検出回路(液面検出回路)
41 バイパス回路
42 減圧機構
43 電磁開閉弁
44 温度センサ(温度検出部)
45 第2液面検出回路
46 電磁開閉弁
47 電磁開閉弁
48 冷媒量検出部
50 ホットガスバイパス回路
51 電磁開閉弁
52 減圧機構
53 温度センサ(温度検出部)
DESCRIPTION OF SYMBOLS 1 Air conditioner 2 Outdoor unit 3 Indoor unit 10 Compressor 12 Outdoor heat exchanger 14 Electric expansion valve for heating (expansion valve for heating)
15 Receiver 18 Supercooling expansion valve (pressure reduction mechanism)
19 Supercooling heat exchanger 20 Supercooling circuit 30 Indoor heat exchanger 32 Electric expansion valve for cooling (Expansion valve for cooling)
33 Gas refrigerant pipe 34 Liquid refrigerant pipe 35 Refrigerant circuit 40 First liquid level detection circuit (liquid level detection circuit)
41 Bypass circuit 42 Pressure reducing mechanism 43 Electromagnetic on-off valve 44 Temperature sensor (temperature detection unit)
45 Second liquid level detection circuit 46 Electromagnetic on-off valve 47 Electromagnetic on-off valve 48 Refrigerant amount detection unit 50 Hot gas bypass circuit 51 Electromagnetic on-off valve 52 Pressure reducing mechanism 53 Temperature sensor (temperature detection unit)

Claims (5)

  1.  圧縮機、室外熱交換器、暖房用膨張弁、液冷媒を貯留するレシーバ、および液冷媒の一部を分流し、該冷媒を減圧機構で減圧した後、過冷却熱交換器で液冷媒と熱交換させ、前記圧縮機の吸入側に戻す過冷却回路等を備えた室外機と、室内熱交換器、冷房用膨張弁等を備えた室内機とをガス冷媒配管および液冷媒配管により接続し、閉サイクルの冷媒回路を構成している空気調和機において、
     前記レシーバの所定高さ位置と前記過冷却回路を介して前記圧縮機の吸入側との間を接続するバイパス回路に開閉弁および減圧機構を介装した第1液面検出回路と、
     前記バイパス回路から分岐され、前記レシーバから取出された冷媒を前記過冷却回路の減圧機構の入口側にバイパスする開閉弁を介装した第2液面検出回路と、
     前記第1液面検出回路または前記第2液面検出回路を含む前記過冷却回路を経て減圧された冷媒の温度を検出する温度検出部と、
     前記レシーバから前記第1液面検出回路または前記第2液面検出回路を介して取出された冷媒の減圧後の温度を前記温度検出部で検出し、該温度に基づいて冷媒充填量を判定する冷媒量検出部と、を備えている空気調和機。
    A compressor, an outdoor heat exchanger, a heating expansion valve, a receiver for storing liquid refrigerant, and a part of the liquid refrigerant are shunted, and after the refrigerant is decompressed by a decompression mechanism, the liquid refrigerant and heat are An outdoor unit provided with a supercooling circuit or the like that is exchanged and returned to the suction side of the compressor, and an indoor unit provided with an indoor heat exchanger, a cooling expansion valve, and the like are connected by a gas refrigerant pipe and a liquid refrigerant pipe, In an air conditioner constituting a closed cycle refrigerant circuit,
    A first liquid level detection circuit including an on-off valve and a pressure reducing mechanism in a bypass circuit connecting between a predetermined height position of the receiver and the suction side of the compressor via the supercooling circuit;
    A second liquid level detection circuit that includes an on-off valve that bypasses the refrigerant branched from the bypass circuit and taken out from the receiver to the inlet side of the decompression mechanism of the supercooling circuit;
    A temperature detection unit for detecting the temperature of the refrigerant decompressed through the supercooling circuit including the first liquid level detection circuit or the second liquid level detection circuit;
    The temperature after depressurization of the refrigerant taken out from the receiver through the first liquid level detection circuit or the second liquid level detection circuit is detected by the temperature detection unit, and the refrigerant filling amount is determined based on the temperature. An air conditioner comprising a refrigerant amount detection unit.
  2.  前記過冷却回路の前記冷媒回路からの分岐部付近に、冷媒充填運転時に閉とされ、通常の冷暖房運転時には開とされる電磁開閉弁が設けられている請求項1に記載の空気調和機。 The air conditioner according to claim 1, wherein an electromagnetic on-off valve is provided near a branch portion of the supercooling circuit from the refrigerant circuit, which is closed during a refrigerant charging operation and opened during a normal air conditioning operation.
  3.  圧縮機、室外熱交換器、暖房用膨張弁および液冷媒を貯留するレシーバ等を備えた室外機と、室内熱交換器、冷房用膨張弁等を備えた室内機とをガス冷媒配管および液冷媒配管により接続し、閉サイクルの冷媒回路を構成している空気調和機において、
     前記レシーバの所定高さ位置と前記圧縮機の吸入側との間を接続するバイパス回路に開閉弁および減圧機構を介装した液面検出回路と、
     前記圧縮機の吐出側から吸入側にホットガスの一部を導入可能な開閉弁および減圧機構を備えているホットガスバイパス回路と、
     前記液面検出回路を経た冷媒または該冷媒と前記ホットガスバイパス回路を経て導入されたホットガスとが混合された冷媒の温度を検出可能な温度検出部と、
     前記レシーバから前記液面検出回路に取出された冷媒または該冷媒と前記ホットガスバイパス回路を経て導入された冷媒との混合冷媒の減圧後の温度を前記温度検出部で検出し、該温度に基づいて冷媒充填量を判定する冷媒量検出部と、を備えている空気調和機。
    Gas refrigerant piping and liquid refrigerant include an outdoor unit including a compressor, an outdoor heat exchanger, a heating expansion valve, and a receiver that stores liquid refrigerant, and an indoor unit including an indoor heat exchanger, a cooling expansion valve, and the like. In an air conditioner connected by piping and constituting a closed-cycle refrigerant circuit,
    A liquid level detection circuit including an on-off valve and a pressure reducing mechanism in a bypass circuit connecting between a predetermined height position of the receiver and a suction side of the compressor;
    A hot gas bypass circuit comprising an on-off valve and a pressure reducing mechanism capable of introducing a part of hot gas from the discharge side to the suction side of the compressor;
    A temperature detection unit capable of detecting the temperature of the refrigerant that has passed through the liquid level detection circuit or a mixture of the refrigerant and hot gas introduced through the hot gas bypass circuit;
    The temperature detection unit detects the temperature after decompression of the refrigerant taken out from the receiver into the liquid level detection circuit or a mixed refrigerant of the refrigerant and the refrigerant introduced through the hot gas bypass circuit, and based on the temperature An air conditioner comprising: a refrigerant amount detection unit that determines a refrigerant charge amount.
  4.  請求項1または2に記載の空気調和機の冷媒量検出方法において、
     冷媒充填運転時、冷房定格程度の温度条件下では、前記第2液面検出回路を前記開閉弁により閉鎖して前記第1液面検出回路を使用し、低外気温条件下では、前記第1液面検出回路を前記開閉弁により閉鎖し、前記第2液面検出回路を使用してそれぞれ液面検出を行う空気調和機の冷媒量検出方法。
    In the refrigerant amount detection method of the air conditioner according to claim 1 or 2,
    During the refrigerant charging operation, the second liquid level detection circuit is closed by the on-off valve under the temperature condition of the cooling rating, and the first liquid level detection circuit is used. Under the low outside air temperature condition, the first liquid level detection circuit is used. A refrigerant amount detection method for an air conditioner, wherein a liquid level detection circuit is closed by the on-off valve and the liquid level detection is performed using the second liquid level detection circuit.
  5.  請求項3に記載の空気調和機の冷媒量検出方法において、
     冷媒充填運転時、冷房定格程度の温度条件下では、前記液面検出回路のみを使用し、低外気温条件下では、前記液面検出回路および前記ホットガスバイパス回路の双方を使用して液面検出を行う空気調和機の冷媒量検出方法。
    In the refrigerant | coolant amount detection method of the air conditioner of Claim 3,
    During the refrigerant charging operation, only the liquid level detection circuit is used under the temperature condition of the cooling rating, and the liquid level detection circuit and the hot gas bypass circuit are both used under the low outside air temperature condition. A refrigerant amount detection method for an air conditioner that performs detection.
PCT/JP2010/071481 2009-12-10 2010-12-01 Air conditioner and refrigerant amount detection method for air conditioner WO2011070954A1 (en)

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