WO2015198431A1 - Refrigeration-cycle device, air conditioner, and method for controlling refrigeration cycle device - Google Patents

Refrigeration-cycle device, air conditioner, and method for controlling refrigeration cycle device Download PDF

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Publication number
WO2015198431A1
WO2015198431A1 PCT/JP2014/066913 JP2014066913W WO2015198431A1 WO 2015198431 A1 WO2015198431 A1 WO 2015198431A1 JP 2014066913 W JP2014066913 W JP 2014066913W WO 2015198431 A1 WO2015198431 A1 WO 2015198431A1
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WIPO (PCT)
Prior art keywords
refrigerant
amount
compressor
condenser
accumulator
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PCT/JP2014/066913
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French (fr)
Japanese (ja)
Inventor
悟 梁池
加藤　央平
大林　誠善
仁隆 門脇
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三菱電機株式会社
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Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to JP2015527730A priority Critical patent/JP5908177B1/en
Priority to PCT/JP2014/066913 priority patent/WO2015198431A1/en
Publication of WO2015198431A1 publication Critical patent/WO2015198431A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B1/00—Compression machines, plants or systems with non-reversible cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat

Definitions

  • the present invention relates to a refrigeration cycle apparatus, an air conditioner, and a control method for the refrigeration cycle apparatus.
  • a compressor, a condenser, a throttling device, an evaporator, and an accumulator are provided with a refrigerant circulation circuit connected in an annular shape, and the outlet pipes of the accumulator have different heights. Some of which are formed with a plurality of small holes located at.
  • the accumulator stores excess refrigerant in the refrigerant circuit. The liquid refrigerant contained in the refrigerant accumulated in the accumulator flows into the outlet pipe through a plurality of small holes and is sucked into the compressor together with the refrigerant (see, for example, Patent Document 1).
  • JP 2013-124800 A paragraph [0027] to paragraph [0050], FIG. 1 etc.
  • the amount of liquid refrigerant sucked into the compressor changes depending on the inner diameter of the small hole, the height at which the small hole is formed, and the like. Therefore, when a small hole design error occurs, or when the refrigeration cycle device enters an operating state that is not assumed at the time of design, excessive liquid refrigerant returns to the compressor, increasing the frequency of compressor failure. As a result, there is a problem that reliability is lowered. In addition, it is necessary to design an accumulator for each model, and there is a problem that versatility is low.
  • the present invention has been made against the background of the above problems, and provides a refrigeration cycle apparatus with improved reliability and versatility. Moreover, such an air conditioning apparatus is obtained. Moreover, the control method of such a refrigeration cycle apparatus is obtained.
  • the refrigeration cycle apparatus includes a refrigerant circulation circuit in which a compressor, a condenser, a first throttle device, an evaporator, and an accumulator are connected in an annular shape, and a second throttle device is connected in the middle.
  • a bypass flow path for bypassing the refrigerant flowing through a portion of the refrigerant circuit between the condenser and the first throttle device to the compressor, the condenser of the refrigerant circuit, and the first throttle device An internal heat exchanger that exchanges heat between the refrigerant flowing between the refrigerant and the refrigerant that has passed through the second expansion device of the bypass channel, and the bypass channel according to the amount of refrigerant in the accumulator And a control means for changing the amount of liquid refrigerant flowing into the compressor via.
  • the control means changes the amount of the liquid refrigerant flowing into the compressor via the bypass flow path according to the refrigerant amount in the accumulator. Therefore, it is possible to control the amount of liquid refrigerant flowing into the compressor to suppress excessive liquid refrigerant from flowing into the compressor, thereby improving the reliability. Further, since the amount of liquid refrigerant flowing into the compressor can be controlled, the accumulator can be used for a plurality of models, and versatility is improved.
  • FIG. It is a figure for demonstrating the structure of the air conditioning apparatus which concerns on Embodiment 1.
  • FIG. It is a Mollier diagram of the refrigeration cycle in the high efficiency operation mode of the air-conditioning apparatus according to Embodiment 1.
  • FIG. It is a figure for demonstrating the structure of the air conditioning apparatus which concerns on Embodiment 2.
  • FIG. It is a figure for demonstrating the structure of the air conditioning apparatus which concerns on Embodiment 3.
  • FIG. It is a Mollier diagram in case a refrigerant
  • the refrigeration cycle apparatus according to the present invention is an air conditioner.
  • the present invention is not limited to such a case, and the refrigeration cycle apparatus according to the present invention is not an air conditioner.
  • Other refrigeration cycle apparatuses may be used.
  • the case where the refrigeration cycle apparatus according to the present invention is an air conditioner that performs only heating will be described.
  • the refrigeration cycle apparatus according to the present invention is not limited to such a case.
  • an air conditioner 100 includes a refrigerant circulation circuit 10 in which a compressor 11, a condenser 12, a first expansion device 13, an evaporator 14, and an accumulator 15 are connected in an annular shape.
  • a refrigeration cycle 1 is provided.
  • the downstream side of the bypass flow path 20 is connected to a portion of the refrigerant circulation circuit 10 between the accumulator 15 and the compressor 11.
  • the condenser 12 exchanges heat between the refrigerant in the refrigerant circuit 10 and the water in the water circuit 40, for example.
  • the water circuit 40 supplies hot water to a heat exchanger or the like of the indoor unit using the pump 41 as a drive source.
  • the air conditioning apparatus 100 includes a control unit 50.
  • the control unit 50 governs the operation of the air conditioning apparatus 100.
  • the control unit 50 includes a compressor 11, a first throttle device 13, a second throttle device 21, a pump 41, a discharge pressure sensor 51 that detects the pressure of refrigerant on the discharge side of the compressor 11, and a suction side of the compressor 11.
  • An intake pressure sensor 52 that detects the pressure of the refrigerant
  • an internal heat exchanger outlet temperature sensor 53 that detects the temperature of the refrigerant on the outlet side of the internal heat exchanger 30, an outside air temperature sensor 54 that detects the outside air temperature, and the like are connected.
  • control unit 50 may be configured by a microcomputer, a microprocessor unit, or the like, may be configured by an updatable component such as firmware, and is executed by a command from the CPU or the like. It may be a program module or the like.
  • the control unit 50 corresponds to the “control unit” in the present invention.
  • a flow path switching device such as a four-way valve is connected to the discharge side of the compressor 11 of the refrigerant circulation circuit 10, and the control unit
  • the flow direction of the refrigerant in the refrigerant circuit 10 is reversed by switching the flow path of the flow path switching device by 50.
  • the controller 50 switches between a high efficiency operation mode, a high pressure suppression operation mode, and a liquid return suppression operation mode.
  • FIG. 2 is a Mollier diagram of the refrigeration cycle in the high efficiency operation mode of the air-conditioning apparatus according to Embodiment 1.
  • the refrigerant discharged from the compressor 11 is in a high-pressure gas state (point A in the figure) and flows into the condenser 12.
  • the refrigerant that has passed through the condenser 12 becomes a supercooled liquid state (point B in the figure) and flows into the internal heat exchanger 30.
  • the refrigerant that has passed through the internal heat exchanger 30 becomes a further supercooled liquid state (point C in the figure) and flows into the first expansion device 13.
  • the refrigerant decompressed by the first expansion device 13 enters a low-pressure gas-liquid two-phase state (point D in the figure) and flows into the evaporator 14.
  • the refrigerant that has passed through the evaporator 14 is in a superheated gas state (point E in the figure), passes through the accumulator 15, and is then sucked into the compressor 11.
  • the refrigerant that has passed through the condenser 12 and has flowed into the bypass flow path 20 flows into the second expansion device 21.
  • the refrigerant decompressed by the second expansion device 21 enters a low-pressure gas-liquid two-phase state (point F in the figure) and flows into the internal heat exchanger 30.
  • the refrigerant that has passed through the internal heat exchanger 30 is sucked into the compressor 11 in a gas-liquid two-phase state (point G in the figure).
  • control unit 50 adjusts the opening degree of the first expansion device 13 to an opening degree at which the degree of supercooling in the condenser 12 is increased and the COP (coefficient of performance) is maximized. Further, the control unit 50 adjusts the opening degree of the second expansion device 21 to an opening degree at which excessive liquid refrigerant does not return to the compressor 11.
  • the amount of refrigerant sealed in the refrigeration cycle 1 may be an amount that does not allow liquid refrigerant to accumulate in the accumulator 15 under the condition that COP (coefficient of performance) is maximized.
  • the control unit 50 may adjust the opening of the second expansion device 21 to an opening that keeps the temperature within a predetermined range.
  • FIG. 3 is a Mollier diagram of the refrigeration cycle in the high-pressure suppression operation mode of the air-conditioning apparatus according to Embodiment 1.
  • the refrigerant discharged from the compressor 11 is in a high-pressure gas state (point A in the figure) and flows into the condenser 12.
  • the refrigerant that has passed through the condenser 12 enters a gas-liquid two-phase state (point B in the figure) and flows into the internal heat exchanger 30.
  • the refrigerant that has passed through the internal heat exchanger 30 becomes a supercooled liquid state (point C in the figure) and flows into the first expansion device 13.
  • the refrigerant decompressed by the first expansion device 13 enters a low-pressure gas-liquid two-phase state (point D in the figure) and flows into the evaporator 14.
  • the refrigerant that has passed through the evaporator 14 is in a superheated gas state (point E in the figure), passes through the accumulator 15, and is then sucked into the compressor 11.
  • the refrigerant that has passed through the condenser 12 and has flowed into the bypass flow path 20 flows into the second expansion device 21.
  • the refrigerant decompressed by the second expansion device 21 enters a low-pressure gas-liquid two-phase state (point F in the figure) and flows into the internal heat exchanger 30.
  • the refrigerant that has passed through the internal heat exchanger 30 is sucked into the compressor 11 in a gas-liquid two-phase state (point G in the figure).
  • the control unit 50 sets the opening of the first expansion device 13 to an opening at which the degree of supercooling in the condenser 12 is not provided, that is, an opening at which the refrigerant enters a gas-liquid two-phase state at the outlet of the condenser 12. It adjusts and it adjusts so that the high voltage
  • the refrigerant cooled by the refrigerant that has passed through the second expansion device 21 of the bypass channel 20 and flowing into the first expansion device 13 is adjusted to an opening degree that becomes a liquid refrigerant.
  • the refrigerant enters a gas-liquid two-phase state at the outlet of the condenser 12 the amount of refrigerant flowing other than the accumulator 15 of the refrigeration cycle 1 is reduced, and excess refrigerant accumulates in the accumulator 15.
  • the control unit 50 shifts to the liquid return suppression operation mode, and adjusts the opening degree of the second expansion device 21 to an opening degree at which the refrigerant is in a gas state (overheated gas state) at the outlet of the internal heat exchanger 30. To do. That is, the control unit 50 reduces the opening of the second expansion device 21 when the amount of refrigerant in the accumulator 15 is large, compared with the case where the amount of refrigerant in the accumulator 15 is small, The amount of liquid refrigerant flowing into the compressor 11 is reduced.
  • FIG. 4 is a diagram for explaining the relationship between the flow rate of the refrigerant and the thickness of the liquid film.
  • the control unit 50 still reduces the frequency of the compressor 11 and determines the opening degree of the first expansion device 13 to the outlet of the evaporator 14 when it is determined that the amount of refrigerant in the accumulator 15 is too large.
  • the opening is adjusted to such an extent that the refrigerant does not enter the superheated gas state.
  • the control unit 50 reduces the frequency of the compressor 11 when the refrigerant amount in the accumulator 15 is large, compared with the case where the refrigerant amount in the accumulator 15 is small, and the liquid refrigerant flowing into the accumulator 15. Reduce the amount. As shown in FIG.
  • control unit 50 acquires the temperature of the refrigerant at the outlet of the internal heat exchanger 30 from the detection result of the internal heat exchanger outlet temperature sensor 53.
  • the control unit 50 acquires the refrigerant pressure at the outlet of the internal heat exchanger 30 from the detection result of the discharge pressure sensor 51.
  • the detection result of the discharge pressure sensor 51 the detection result of the temperature sensor that detects the temperature of the refrigerant at the location where the refrigerant of the condenser 12 is in a two-phase state is used, and the saturation pressure obtained from the detection result of the temperature sensor is May be acquired.
  • the condenser 12 exchanges heat between the refrigerant in the refrigerant circuit 10 and the water in the water circuit 40, the condensation temperature of the refrigeration cycle 1 and the temperature of water flowing out of the condenser 12 are substantially equal. Therefore, instead of the detection result of the discharge pressure sensor 51, the detection result of the temperature sensor that detects the temperature of the water flowing out of the condenser 12 is used, and the saturation pressure obtained from the detection result of the temperature sensor is acquired. May be.
  • the control unit 50 acquires the refrigerant pressure on the suction side of the compressor 11 from the detection result of the suction pressure sensor 52.
  • the detection result of the suction pressure sensor 52 the detection result of the temperature sensor that detects the temperature of the refrigerant at the location where the refrigerant of the evaporator 14 is in a two-phase state is used, and the saturation pressure obtained from the detection result of the temperature sensor is May be acquired.
  • the refrigerant is always present in the accumulator 15, the refrigerant at the outlet of the accumulator 15 is in a gas-liquid two-phase state. Therefore, instead of the detection result of the suction pressure sensor 52, the temperature of the refrigerant at the outlet of the accumulator 15.
  • the detection result of the temperature sensor for detecting the temperature sensor may be used, and the saturation pressure obtained from the detection result of the temperature sensor may be acquired.
  • the control unit 50 estimates the exchange heat quantity Qa in the internal heat exchanger 30.
  • the heat exchange amount Q of the heat exchanger is generally expressed by the following equation (1), where A is the heat transfer area, K is the heat transfer coefficient, and ⁇ T is the temperature difference.
  • the heat transfer area A is determined from the specifications of the internal heat exchanger 30.
  • the temperature difference ⁇ T is determined from the refrigerant temperature at the outlet of the internal heat exchanger 30 and the saturation temperature obtained from the refrigerant pressure on the suction side of the compressor 11.
  • the heat transfer coefficient K is proportional to the Reynolds number Re.
  • the Reynolds number Re is generally expressed by the following equation (2), where u is a flow velocity, d is a representative diameter, and v is a kinematic viscosity coefficient.
  • u is a flow velocity
  • d is a representative diameter
  • v is a kinematic viscosity coefficient.
  • the heat transfer coefficient K can be estimated using the amount Gra, the refrigerant circulation amount Grab of the bypass passage 20, and the relationship between the Reynolds number Re acquired in advance and the characteristics of the internal heat exchanger 30.
  • the refrigerant circulation amount Gra of the refrigerant circuit 10 can be estimated from the refrigerant pressure on the suction side of the compressor 11 and the frequency f of the compressor 11, the refrigerant density is ⁇ s, the stroke volume of the compressor 11 is V, When the volume efficiency of the compressor 11 is ⁇ v, it is expressed by the following equation (3).
  • the refrigerant circulation amount Grb in the bypass flow path 20 includes the Cv value of the second expansion device 21 obtained from the opening of the second expansion device 21, the differential pressure ⁇ P before and after passing through the second expansion device 21 of the refrigerant, If the specific gravity of the refrigerant is G and the coefficient is C, it is represented by the following equation (4).
  • the control unit 50 estimates the quality (dryness) of the refrigerant at the outlet of the condenser 12.
  • the quality (dryness) can be estimated from the refrigerant pressure at the outlet of the internal heat exchanger 30 and the refrigerant enthalpy at the outlet of the condenser 12.
  • the refrigerant enthalpy h2 at the outlet of the condenser 12 is estimated from the refrigerant enthalpy h1 at the outlet of the internal heat exchanger 30, the exchange heat quantity Qa of the internal heat exchanger 30, and the refrigerant circulation quantity Gra of the refrigerant circulation circuit 10. And is represented by the following equation (5).
  • the enthalpy h1 of the refrigerant at the outlet of the internal heat exchanger 30 is obtained from the pressure and temperature of the refrigerant at the outlet of the internal heat exchanger 30.
  • the control unit 50 estimates the amount of refrigerant in the condenser 12.
  • the refrigerant quantity of the condenser 12 can be estimated from the ratio of the liquid refrigerant quantity and the gas refrigerant quantity in the condenser 12.
  • the ratio between the liquid refrigerant amount and the gas refrigerant amount in the condenser 12 can be estimated from the refrigerant pressure at the outlet of the internal heat exchanger 30 and the refrigerant quality (dryness) at the outlet of the condenser 12. .
  • the relationship between the refrigerant pressure at the outlet of the internal heat exchanger 30, the quality (dryness) of the refrigerant at the outlet of the condenser 12, and the refrigerant quantity of the condenser 12 is acquired in advance, and the refrigerant quantity of the condenser 12 is It may be estimated using the relationship.
  • the control unit 50 estimates the exchange heat quantity Qb in the evaporator 14.
  • the heat transfer area A is determined from the specifications of the evaporator 14.
  • the temperature difference ⁇ T is determined from the saturation temperature obtained from the detection result of the suction pressure sensor 52 and the outside air temperature acquired from the detection result of the outside air temperature sensor 54.
  • the heat transfer coefficient K may be estimated from the heat exchange performance of the fins. Since the heat exchange performance of the fin is proportional to the amount of air blown from the fan, the relationship between the amount of air blown from the fan and the heat transfer characteristics is acquired in advance, and the heat transfer coefficient K is estimated using the relationship. Good. The amount of air blown from the fan can be converted from the rotational speed of the fan.
  • the control unit 50 estimates the quality (dryness) of the refrigerant at the outlet of the evaporator 14.
  • the quality (dryness) can be estimated from the refrigerant pressure on the suction side of the compressor 11 and the refrigerant enthalpy at the outlet of the evaporator 14.
  • the refrigerant enthalpy h3 at the outlet of the evaporator 14 can be estimated from the refrigerant enthalpy h1 at the outlet of the internal heat exchanger 30, the exchange heat quantity Qb of the evaporator 14, and the refrigerant circulation amount Gra of the refrigerant circuit 10. It is represented by the following formula (6).
  • the control unit 50 estimates the amount of refrigerant in the evaporator 14.
  • the refrigerant amount of the evaporator 14 can be estimated from the ratio of the liquid refrigerant amount and the gas refrigerant amount in the evaporator 14.
  • the ratio between the liquid refrigerant amount and the gas refrigerant amount in the evaporator 14 can be estimated from the refrigerant pressure on the suction side of the compressor 11 and the quality (dryness) of the refrigerant at the outlet of the evaporator 14.
  • the relationship between the refrigerant pressure on the suction side of the compressor 11, the refrigerant quality (dryness) at the outlet of the evaporator 14, and the refrigerant amount of the evaporator 14 is acquired in advance, and the refrigerant amount of the evaporator 14 is It is good to estimate using the relationship.
  • the control unit 50 estimates the amount of refrigerant in the accumulator 15.
  • the amount of refrigerant in the accumulator 15 can be estimated by subtracting the amount of refrigerant in the condenser 12 and the amount of refrigerant in the evaporator 14 from the amount of refrigerant enclosed in the refrigeration cycle 1. That is, the refrigerant amount in the accumulator 15 can be estimated based on the refrigerant amount distribution in the refrigeration cycle 1.
  • the control unit 50 reduces the frequency of the compressor 11 when it is still determined that the amount of refrigerant in the accumulator 15 is too large. Therefore, it is possible to increase the amount of refrigerant stored in the evaporator 14 and reduce the amount of liquid refrigerant that returns to the compressor 11, so that the reliability of the compressor 11 is improved.
  • FIG. 5 is a diagram for explaining the configuration of the air-conditioning apparatus according to Embodiment 2.
  • the condenser 12 exchanges heat between the refrigerant in the refrigerant circuit 10 and the water in the water circuit 40.
  • the water circuit 40 supplies hot water to a heat exchanger or the like of the indoor unit using the pump 41 as a drive source.
  • the control unit 50 includes a compressor 11, a first throttle device 13, a second throttle device 21, a pump 41, a discharge pressure sensor 51 that detects the pressure of refrigerant on the discharge side of the compressor 11, and a suction side of the compressor 11.
  • An intake pressure sensor 52 that detects the pressure of the refrigerant
  • an internal heat exchanger outlet temperature sensor 53 that detects the temperature of the refrigerant on the outlet side of the internal heat exchanger 30, an outside air temperature sensor 54 that detects the outside air temperature, and the discharge of the compressor 11
  • a discharge temperature sensor 55 for detecting the temperature of the refrigerant on the side, an incoming water temperature sensor 56 for detecting the temperature of the water flowing into the condenser 12, a hot water temperature sensor 57 for detecting the temperature of the water flowing out of the condenser 12, and the like are connected.
  • the control unit 50 acquires the pressure and temperature of the refrigerant on the discharge side of the compressor 11 from the detection result of the discharge pressure sensor 51 and the detection result of the discharge temperature sensor 55. Further, the control unit 50 acquires the temperature Twin of water flowing into the condenser 12 and the temperature Twout of water flowing out of the condenser 12 from the detection result of the incoming water temperature sensor 56 and the detection result of the hot water temperature sensor 57.
  • the control unit 50 estimates the exchange heat quantity Qc in the condenser 12.
  • the exchange heat quantity Qc in the condenser 12 can be estimated from the difference between the temperature Twin of the water flowing into the condenser 12 and the temperature Twout of the water flowing out of the condenser 12 and the water flow rate Gw.
  • the specific heat of the water is Cpw, If the density is ⁇ w, it is expressed by the following equation (7).
  • the water flow rate Gw is obtained from the rotational speed of the pump 41. Further, the specific heat Cpw of water and the density ⁇ w of water are obtained from the temperature of the water.
  • control unit 50 estimates the quality (dryness) of the refrigerant at the outlet of the condenser 12.
  • the quality (dryness) can be estimated from the refrigerant pressure on the discharge side of the compressor 11 and the refrigerant enthalpy at the outlet of the condenser 12.
  • the refrigerant enthalpy h2 at the outlet of the condenser 12 can be estimated from the refrigerant enthalpy h0 on the discharge side of the compressor 11, the exchange heat amount Qc of the condenser 12, and the refrigerant circulation amount Gra of the refrigerant circuit 10, and the following (8)
  • the refrigerant enthalpy h0 on the discharge side of the compressor 11 is obtained from the pressure and temperature of the refrigerant on the discharge side of the compressor 11.
  • control unit 50 estimates the amount of refrigerant in the condenser 12.
  • the refrigerant quantity of the condenser 12 can be estimated from the ratio of the liquid refrigerant quantity and the gas refrigerant quantity in the condenser 12.
  • the ratio between the liquid refrigerant amount and the gas refrigerant amount in the condenser 12 can be estimated from the refrigerant pressure on the discharge side of the compressor 11 and the quality (dryness) of the refrigerant at the outlet of the condenser 12.
  • the relationship between the refrigerant pressure on the discharge side of the compressor 11, the quality (dryness) of the refrigerant at the outlet of the condenser 12, and the refrigerant amount of the condenser 12 is acquired in advance, and the refrigerant amount of the condenser 12 is It is good to estimate using the relationship.
  • the control unit 50 estimates the exchange heat quantity Qb in the evaporator 14.
  • the heat transfer area A is determined from the specifications of the evaporator 14.
  • the temperature difference ⁇ T is determined from the saturation temperature obtained from the detection result of the suction pressure sensor 52 and the outside air temperature acquired from the detection result of the outside air temperature sensor 54.
  • the heat transfer coefficient K may be estimated from the heat exchange performance of the fins. Since the heat exchange performance of the fin is proportional to the amount of air blown from the fan, the relationship between the amount of air blown from the fan and the heat transfer characteristics is acquired in advance, and the heat transfer coefficient K is estimated using the relationship. Good. The amount of air blown from the fan can be converted from the rotational speed of the fan.
  • the control unit 50 estimates the quality (dryness) of the refrigerant at the outlet of the evaporator 14.
  • the quality (dryness) can be estimated from the refrigerant pressure on the suction side of the compressor 11 and the refrigerant enthalpy at the outlet of the evaporator 14.
  • the refrigerant enthalpy h3 at the outlet of the evaporator 14 can be estimated from the refrigerant enthalpy h1 at the outlet of the internal heat exchanger 30, the exchange heat quantity Qb of the evaporator 14, and the refrigerant circulation amount Gra of the refrigerant circuit 10. It is represented by the following formula (9).
  • the control unit 50 estimates the amount of refrigerant in the evaporator 14.
  • the refrigerant amount of the evaporator 14 can be estimated from the ratio of the liquid refrigerant amount and the gas refrigerant amount in the evaporator 14.
  • the ratio between the liquid refrigerant amount and the gas refrigerant amount in the evaporator 14 can be estimated from the refrigerant pressure on the suction side of the compressor 11 and the quality (dryness) of the refrigerant at the outlet of the evaporator 14.
  • the relationship between the refrigerant pressure on the suction side of the compressor 11, the refrigerant quality (dryness) at the outlet of the evaporator 14, and the refrigerant amount of the evaporator 14 is acquired in advance, and the refrigerant amount of the evaporator 14 is It is good to estimate using the relationship.
  • the control unit 50 estimates the amount of refrigerant in the accumulator 15.
  • the amount of refrigerant in the accumulator 15 can be estimated by subtracting the amount of refrigerant in the condenser 12 and the amount of refrigerant in the evaporator 14 from the amount of refrigerant enclosed in the refrigeration cycle 1. That is, the refrigerant amount in the accumulator 15 can be estimated based on the refrigerant amount distribution in the refrigeration cycle 1.
  • the control unit 50 controls the refrigerant enthalpy h ⁇ b> 2 at the outlet of the condenser 12, the refrigerant enthalpy h ⁇ b> 0 on the discharge side of the compressor 11, the exchange heat quantity Qc of the condenser 12, and the refrigerant circulation circuit 10. It is estimated from the refrigerant circulation amount Gra. Therefore, the control unit 50 determines the refrigerant enthalpy h2 at the outlet of the condenser 12, the refrigerant enthalpy h1 at the outlet of the internal heat exchanger 30, the exchange heat quantity Qa of the internal heat exchanger 30, and the refrigerant of the refrigerant circulation circuit 10.
  • the estimation of the refrigerant amount of the condenser 12 is improved, and the certainty of reducing the amount of liquid refrigerant returning to the compressor 11 is improved. This further improves the reliability of the compressor 11.
  • FIG. 6 is a diagram for explaining the configuration of the air-conditioning apparatus according to Embodiment 3. As shown in FIG. 6, the downstream side of the bypass flow path 20 is connected to a compressor of the compressor 11 that compresses the refrigerant.
  • the downstream side of the bypass channel 20 is connected to the compression unit of the compressor 11, and the refrigerant in the bypass channel 20 flows directly into the compression unit of the compressor 11.
  • the downstream side is connected to the portion between the accumulator 15 and the compressor 11 of the refrigerant circulation circuit 10 and the refrigerant in the bypass flow path 20 flows into the compressor 11 from the suction port of the compressor 11.
  • the amount of liquid refrigerant that accumulates at the shell bottom of the compressor 11 is reduced. Therefore, it is suppressed that the lubricating oil collected on the shell bottom of the compressor 11 is diluted with the liquid refrigerant, and the reliability of the compressor 11 is further improved.
  • the quality (dryness) of the refrigerant in the bypass channel 20 can be lowered.
  • Embodiment 4 FIG.
  • the air conditioner according to Embodiment 4 will be described below. In the following description, descriptions overlapping or similar to those in Embodiments 1 to 3 are appropriately simplified or omitted.
  • ⁇ Configuration of air conditioner> The configuration of the air conditioner 100 is the same as the configuration of the air conditioner 100 shown in the first to third embodiments. As the refrigerant of the refrigeration cycle 1, HFO1234yf or HFO1234ze is used.
  • FIG. 7 is a Mollier diagram in the case where the refrigerant is HFO1234yf or HFO1234ze.
  • the refrigerant temperature on the discharge side of the compressor 11 is lower than that when the refrigerant is R410A or the like, and excessively flows into the compressor 11.
  • the refrigerant on the discharge side of the compressor 11 is in a gas-liquid two-phase state in addition to the refrigerant on the suction side of the compressor 11 (that is, the gas-liquid two-phase state is set over the entire compression stroke).
  • an excessive load is easily applied to the compressor 11. Therefore, compared with the case where the refrigerant is R410A or the like, it is more important for the air conditioner 100 to perform the operations shown in the first to third embodiments, and the reliability of the compressor 11 is improved. The effect of improving is remarkable.
  • Refrigeration cycle 10 Refrigerant circulation circuit, 11 Compressor, 12 Condenser, 13 1st expansion device, 14 Evaporator, 15 Accumulator, 20 Bypass channel, 21 2nd expansion device, 30 Internal heat exchanger, 40 Water circuit , 41 pump, 50 control unit, 51 discharge pressure sensor, 52 suction pressure sensor, 53 internal heat exchanger outlet temperature sensor, 54 outside air temperature sensor, 55 discharge temperature sensor, 56 incoming water temperature sensor, 57 hot water temperature sensor, 100 air conditioning apparatus.

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  • Air Conditioning Control Device (AREA)

Abstract

　A refrigeration-cycle device in which reliability and versatility are improved is obtained in the present invention. The refrigeration-cycle device is provided with: a refrigerant circulation circuit (10) in which a compressor (11), a condenser (12), a first aperture device (13), an evaporator (14), and an accumulator (15) are connected in an annular configuration; a bypass flow path (20) having a second aperture device (21) connected partway therealong, refrigerant that flows through the portion between the condenser (12) of the refrigeration circulation circuit (10) and the first aperture device (13) being bypassed to the compressor (11); an internal heat exchanger (30) for exchanging heat between the refrigerant flowing through the portion between the condenser (12) of the refrigerant circulation circuit (10) and the first aperture device (13), and the refrigerant that has passed through the second aperture device (21) of the bypass flow path (20); and a control means for varying the amount of liquid refrigerant flowing into the compressor (11) via the bypass flow path (20) in accordance with the amount of refrigerant in the accumulator (15).

Description

冷凍サイクル装置、空気調和装置、及び、冷凍サイクル装置の制御方法Refrigeration cycle apparatus, air conditioner, and control method for refrigeration cycle apparatus
　本発明は、冷凍サイクル装置と、空気調和装置と、冷凍サイクル装置の制御方法と、に関するものである。 The present invention relates to a refrigeration cycle apparatus, an air conditioner, and a control method for the refrigeration cycle apparatus.
　従来の冷凍サイクル装置として、例えば、圧縮機と、凝縮器と、絞り装置と、蒸発器と、アキュムレータと、が環状に接続された冷媒循環回路を備え、アキュムレータの出口管に、互いに異なる高さに位置する複数の小穴が形成されたものがある。アキュムレータには、冷媒循環回路の余剰な冷媒が貯留される。アキュムレータに溜まった冷媒に含まれる液冷媒は、複数の小穴から出口管に流入して、冷媒とともに圧縮機に吸入される（例えば、特許文献１を参照。）。 As a conventional refrigeration cycle apparatus, for example, a compressor, a condenser, a throttling device, an evaporator, and an accumulator are provided with a refrigerant circulation circuit connected in an annular shape, and the outlet pipes of the accumulator have different heights. Some of which are formed with a plurality of small holes located at. The accumulator stores excess refrigerant in the refrigerant circuit. The liquid refrigerant contained in the refrigerant accumulated in the accumulator flows into the outlet pipe through a plurality of small holes and is sucked into the compressor together with the refrigerant (see, for example, Patent Document 1).
特開２０１３－１２４８００号公報（段落［００２７］～段落［００５０］、図１等）JP 2013-124800 A (paragraph [0027] to paragraph [0050], FIG. 1 etc.)
　従来の冷凍サイクル装置では、小穴の内径、小穴が形成される高さ等に依存して、圧縮機に吸入される液冷媒の量が変化する。そのため、小穴の設計ミスが生じた場合、冷凍サイクル装置が設計時に想定されていない運転状態になった場合等に、過度の液冷媒が圧縮機に戻ってしまい、圧縮機の故障の頻度が増加して信頼性が低下するという問題点があった。また、機種毎にアキュムレータを専用設計する必要があり、汎用性が低いという問題点があった。 In the conventional refrigeration cycle apparatus, the amount of liquid refrigerant sucked into the compressor changes depending on the inner diameter of the small hole, the height at which the small hole is formed, and the like. Therefore, when a small hole design error occurs, or when the refrigeration cycle device enters an operating state that is not assumed at the time of design, excessive liquid refrigerant returns to the compressor, increasing the frequency of compressor failure. As a result, there is a problem that reliability is lowered. In addition, it is necessary to design an accumulator for each model, and there is a problem that versatility is low.
　本発明は、上記のような課題を背景としてなされたものであり、信頼性と汎用性とが向上された冷凍サイクル装置を得るものである。また、そのような空気調和装置を得るものである。また、そのような冷凍サイクル装置の制御方法を得るものである。 The present invention has been made against the background of the above problems, and provides a refrigeration cycle apparatus with improved reliability and versatility. Moreover, such an air conditioning apparatus is obtained. Moreover, the control method of such a refrigeration cycle apparatus is obtained.
　本発明に係る冷凍サイクル装置は、圧縮機と、凝縮器と、第１絞り装置と、蒸発器と、アキュムレータと、が環状に接続された冷媒循環回路と、途中部に第２絞り装置が接続され、前記冷媒循環回路の前記凝縮器と前記第１絞り装置との間の部分を流れる冷媒を前記圧縮機にバイパスするバイパス流路と、前記冷媒循環回路の前記凝縮器と前記第１絞り装置との間の部分を流れる冷媒と、前記バイパス流路の前記第２絞り装置を通過した冷媒と、を熱交換させる内部熱交換器と、前記アキュムレータ内の冷媒量に応じて、前記バイパス流路を介して前記圧縮機に流入する液冷媒の量を変化させる制御手段と、を備えたものである。 The refrigeration cycle apparatus according to the present invention includes a refrigerant circulation circuit in which a compressor, a condenser, a first throttle device, an evaporator, and an accumulator are connected in an annular shape, and a second throttle device is connected in the middle. A bypass flow path for bypassing the refrigerant flowing through a portion of the refrigerant circuit between the condenser and the first throttle device to the compressor, the condenser of the refrigerant circuit, and the first throttle device An internal heat exchanger that exchanges heat between the refrigerant flowing between the refrigerant and the refrigerant that has passed through the second expansion device of the bypass channel, and the bypass channel according to the amount of refrigerant in the accumulator And a control means for changing the amount of liquid refrigerant flowing into the compressor via.
　本発明に係る冷凍サイクル装置では、制御手段が、アキュムレータ内の冷媒量に応じて、バイパス流路を介して圧縮機に流入する液冷媒の量を変化させる。そのため、圧縮機に流入する液冷媒の量を制御して、過度の液冷媒が圧縮機に流入することを抑制することが可能となって、信頼性が向上される。また、圧縮機に流入する液冷媒の量を制御することが可能であるため、アキュムレータを複数機種に流用することが可能となって、汎用性が向上される。 In the refrigeration cycle apparatus according to the present invention, the control means changes the amount of the liquid refrigerant flowing into the compressor via the bypass flow path according to the refrigerant amount in the accumulator. Therefore, it is possible to control the amount of liquid refrigerant flowing into the compressor to suppress excessive liquid refrigerant from flowing into the compressor, thereby improving the reliability. Further, since the amount of liquid refrigerant flowing into the compressor can be controlled, the accumulator can be used for a plurality of models, and versatility is improved.
実施の形態１に係る空気調和装置の、構成を説明するための図である。It is a figure for demonstrating the structure of the air conditioning apparatus which concerns on Embodiment 1. FIG. 実施の形態１に係る空気調和装置の、高効率運転モードにおける冷凍サイクルのモリエル線図である。It is a Mollier diagram of the refrigeration cycle in the high efficiency operation mode of the air-conditioning apparatus according to Embodiment 1. 実施の形態１に係る空気調和装置の、高圧抑制運転モードにおける冷凍サイクルのモリエル線図である。It is a Mollier diagram of the refrigeration cycle in the high pressure suppression operation mode of the air-conditioning apparatus according to Embodiment 1. 冷媒の流速と液膜の厚さとの関係を説明するための図である。It is a figure for demonstrating the relationship between the flow rate of a refrigerant | coolant, and the thickness of a liquid film. 実施の形態２に係る空気調和装置の、構成を説明するための図である。It is a figure for demonstrating the structure of the air conditioning apparatus which concerns on Embodiment 2. FIG. 実施の形態３に係る空気調和装置の、構成を説明するための図である。It is a figure for demonstrating the structure of the air conditioning apparatus which concerns on Embodiment 3. FIG. 冷媒がＨＦＯ１２３４ｙｆ又はＨＦＯ１２３４ｚｅである場合のモリエル線図である。It is a Mollier diagram in case a refrigerant | coolant is HFO1234yf or HFO1234ze.
　以下、本発明に係る冷凍サイクル装置について、図面を用いて説明する。
　なお、以下では、本発明に係る冷凍サイクル装置が、空気調和装置である場合について説明しているが、そのような場合に限定されず、本発明に係る冷凍サイクル装置が、空気調和装置以外の他の冷凍サイクル装置であってもよい。また、以下では、本発明に係る冷凍サイクル装置が、暖房のみを行う空気調和装置である場合について説明しているが、そのような場合に限定されず、本発明に係る冷凍サイクル装置が、暖房と冷房とを切り換える空気調和装置であってもよい。また、以下で説明する構成、動作等は、一例にすぎず、本発明に係る冷凍サイクル装置は、そのような構成、動作等である場合に限定されない。また、構成、動作等の細かい説明については、適宜簡略化又は省略している。また、重複又は類似する説明については、適宜簡略化又は省略している。 Hereinafter, a refrigeration cycle apparatus according to the present invention will be described with reference to the drawings.
In the following, the case where the refrigeration cycle apparatus according to the present invention is an air conditioner is described. However, the present invention is not limited to such a case, and the refrigeration cycle apparatus according to the present invention is not an air conditioner. Other refrigeration cycle apparatuses may be used. In the following, the case where the refrigeration cycle apparatus according to the present invention is an air conditioner that performs only heating will be described. However, the refrigeration cycle apparatus according to the present invention is not limited to such a case. And an air conditioner that switches between cooling and cooling. Moreover, the structure, operation | movement, etc. which are demonstrated below are only examples, and the refrigeration cycle apparatus which concerns on this invention is not limited to the case where it is such a structure, operation | movement, etc. In addition, detailed descriptions of the configuration, operation, and the like are appropriately simplified or omitted. In addition, overlapping or similar descriptions are appropriately simplified or omitted.
実施の形態１．
　以下に、実施の形態１に係る空気調和装置について説明する。
＜空気調和装置の構成＞
　図１は、実施の形態１に係る空気調和装置の、構成を説明するための図である。
　図１に示されるように、空気調和装置１００は、圧縮機１１と、凝縮器１２と、第１絞り装置１３と、蒸発器１４と、アキュムレータ１５と、が環状に接続された冷媒循環回路１０と、途中部に第２絞り装置２１が接続され、冷媒循環回路１０の凝縮器１２と第１絞り装置１３との間の部分を流れる冷媒を圧縮機１１にバイパスするバイパス流路２０と、冷媒循環回路１０の凝縮器１２と第１絞り装置１３との間の部分を流れる冷媒と、バイパス流路２０の第２絞り装置２１を通過した冷媒と、を熱交換させる内部熱交換器３０と、を含む、冷凍サイクル１を備える。バイパス流路２０の下流側は、冷媒循環回路１０のアキュムレータ１５と圧縮機１１との間の部分に接続される。 Embodiment 1 FIG.
Below, the air conditioning apparatus which concerns on Embodiment 1 is demonstrated.
<Configuration of air conditioner>
1 is a diagram for explaining a configuration of an air-conditioning apparatus according to Embodiment 1. FIG.
As shown in FIG. 1, an air conditioner 100 includes a refrigerant circulation circuit 10 in which a compressor 11, a condenser 12, a first expansion device 13, an evaporator 14, and an accumulator 15 are connected in an annular shape. A bypass passage 20 for bypassing the refrigerant flowing through the portion between the condenser 12 and the first throttle device 13 of the refrigerant circulation circuit 10 to the compressor 11, An internal heat exchanger 30 for exchanging heat between the refrigerant flowing through the portion between the condenser 12 of the circulation circuit 10 and the first expansion device 13 and the refrigerant that has passed through the second expansion device 21 of the bypass flow path 20; A refrigeration cycle 1 is provided. The downstream side of the bypass flow path 20 is connected to a portion of the refrigerant circulation circuit 10 between the accumulator 15 and the compressor 11.
　凝縮器１２は、例えば、冷媒循環回路１０の冷媒と水回路４０の水とを熱交換させる。水回路４０は、ポンプ４１を駆動源として、室内機の熱交換器等に温水を供給するものである。 The condenser 12 exchanges heat between the refrigerant in the refrigerant circuit 10 and the water in the water circuit 40, for example. The water circuit 40 supplies hot water to a heat exchanger or the like of the indoor unit using the pump 41 as a drive source.
　空気調和装置１００は、制御部５０を備える。制御部５０は、空気調和装置１００の動作を司る。制御部５０には、圧縮機１１、第１絞り装置１３、第２絞り装置２１、ポンプ４１、圧縮機１１の吐出側の冷媒の圧力を検知する吐出圧力センサー５１、圧縮機１１の吸入側の冷媒の圧力を検知する吸入圧力センサー５２、内部熱交換器３０の出口側の冷媒の温度を検知する内部熱交換器出口温度センサー５３、外気温度を検知する外気温度センサー５４等が接続される。制御部５０の全て又は一部は、マイコン、マイクロプロセッサユニット等で構成されてもよく、また、ファームウェア等の更新可能なもので構成されてもよく、また、ＣＰＵ等からの指令によって実行されるプログラムモジュール等であってもよい。制御部５０は、本発明における「制御手段」に相当する。 The air conditioning apparatus 100 includes a control unit 50. The control unit 50 governs the operation of the air conditioning apparatus 100. The control unit 50 includes a compressor 11, a first throttle device 13, a second throttle device 21, a pump 41, a discharge pressure sensor 51 that detects the pressure of refrigerant on the discharge side of the compressor 11, and a suction side of the compressor 11. An intake pressure sensor 52 that detects the pressure of the refrigerant, an internal heat exchanger outlet temperature sensor 53 that detects the temperature of the refrigerant on the outlet side of the internal heat exchanger 30, an outside air temperature sensor 54 that detects the outside air temperature, and the like are connected. All or part of the control unit 50 may be configured by a microcomputer, a microprocessor unit, or the like, may be configured by an updatable component such as firmware, and is executed by a command from the CPU or the like. It may be a program module or the like. The control unit 50 corresponds to the “control unit” in the present invention.
　なお、空気調和装置１００が、暖房と冷房とを切り換えるものである場合には、例えば、冷媒循環回路１０の圧縮機１１の吐出側に、四方弁等の流路切換装置が接続され、制御部５０によって流路切換装置の流路が切り換えられることで、冷媒循環回路１０の冷媒の循環方向が反転される。 When the air conditioner 100 switches between heating and cooling, for example, a flow path switching device such as a four-way valve is connected to the discharge side of the compressor 11 of the refrigerant circulation circuit 10, and the control unit The flow direction of the refrigerant in the refrigerant circuit 10 is reversed by switching the flow path of the flow path switching device by 50.
＜空気調和装置の動作＞
　制御部５０は、高効率運転モードと、高圧抑制運転モードと、液戻り抑制運転モードと、を切り換える。 <Operation of air conditioner>
The controller 50 switches between a high efficiency operation mode, a high pressure suppression operation mode, and a liquid return suppression operation mode.
［高効率運転モード］
　図２は、実施の形態１に係る空気調和装置の、高効率運転モードにおける冷凍サイクルのモリエル線図である。
　高効率運転モードにおける冷凍サイクル１では、図２に示されるように、圧縮機１１から吐出された冷媒は、高圧のガス状態となって（図中Ａ点）、凝縮器１２に流入する。凝縮器１２を通過した冷媒は、過冷却された液状態となって（図中Ｂ点）、内部熱交換器３０に流入する。内部熱交換器３０を通過した冷媒は、更に過冷却された液状態となって（図中Ｃ点）、第１絞り装置１３に流入する。第１絞り装置１３で減圧された冷媒は、低圧の気液二相状態となって（図中Ｄ点）、蒸発器１４に流入する。蒸発器１４を通過した冷媒は、過熱されたガス状態となって（図中Ｅ点）、アキュムレータ１５を通過した後に圧縮機１１に吸入される。また、凝縮器１２を通過してバイパス流路２０に流入した冷媒は、第２絞り装置２１に流入する。第２絞り装置２１で減圧された冷媒は、低圧の気液二相状態となって（図中Ｆ点）、内部熱交換器３０に流入する。内部熱交換器３０を通過した冷媒は、気液二相状態のまま（図中Ｇ点）、圧縮機１１に吸入される。 [High efficiency operation mode]
FIG. 2 is a Mollier diagram of the refrigeration cycle in the high efficiency operation mode of the air-conditioning apparatus according to Embodiment 1.
In the refrigeration cycle 1 in the high-efficiency operation mode, as shown in FIG. 2, the refrigerant discharged from the compressor 11 is in a high-pressure gas state (point A in the figure) and flows into the condenser 12. The refrigerant that has passed through the condenser 12 becomes a supercooled liquid state (point B in the figure) and flows into the internal heat exchanger 30. The refrigerant that has passed through the internal heat exchanger 30 becomes a further supercooled liquid state (point C in the figure) and flows into the first expansion device 13. The refrigerant decompressed by the first expansion device 13 enters a low-pressure gas-liquid two-phase state (point D in the figure) and flows into the evaporator 14. The refrigerant that has passed through the evaporator 14 is in a superheated gas state (point E in the figure), passes through the accumulator 15, and is then sucked into the compressor 11. In addition, the refrigerant that has passed through the condenser 12 and has flowed into the bypass flow path 20 flows into the second expansion device 21. The refrigerant decompressed by the second expansion device 21 enters a low-pressure gas-liquid two-phase state (point F in the figure) and flows into the internal heat exchanger 30. The refrigerant that has passed through the internal heat exchanger 30 is sucked into the compressor 11 in a gas-liquid two-phase state (point G in the figure).
　つまり、制御部５０は、第１絞り装置１３の開度を、凝縮器１２における過冷却度が大きくなって、ＣＯＰ（成績係数）が最大となる開度に調節する。また、制御部５０は、第２絞り装置２１の開度を、圧縮機１１に過度の液冷媒が戻らない開度に調節する。冷凍サイクル１に封入される冷媒量は、ＣＯＰ（成績係数）が最大となる条件において、アキュムレータ１５に液冷媒が溜まらない量であるとよい。圧縮機１１の吐出側の冷媒の温度が過度に上昇する場合に、制御部５０が、第２絞り装置２１の開度を、その温度が所定範囲に収まる開度に調節してもよい。 That is, the control unit 50 adjusts the opening degree of the first expansion device 13 to an opening degree at which the degree of supercooling in the condenser 12 is increased and the COP (coefficient of performance) is maximized. Further, the control unit 50 adjusts the opening degree of the second expansion device 21 to an opening degree at which excessive liquid refrigerant does not return to the compressor 11. The amount of refrigerant sealed in the refrigeration cycle 1 may be an amount that does not allow liquid refrigerant to accumulate in the accumulator 15 under the condition that COP (coefficient of performance) is maximized. When the temperature of the refrigerant on the discharge side of the compressor 11 rises excessively, the control unit 50 may adjust the opening of the second expansion device 21 to an opening that keeps the temperature within a predetermined range.
［高圧抑制運転モード］
　図３は、実施の形態１に係る空気調和装置の、高圧抑制運転モードにおける冷凍サイクルのモリエル線図である。
　高圧抑制運転モードにおける冷凍サイクル１では、図３に示されるように、圧縮機１１から吐出された冷媒は、高圧のガス状態となって（図中Ａ点）、凝縮器１２に流入する。凝縮器１２を通過した冷媒は、気液二相状態となって（図中Ｂ点）、内部熱交換器３０に流入する。内部熱交換器３０を通過した冷媒は、過冷却された液状態となって（図中Ｃ点）、第１絞り装置１３に流入する。第１絞り装置１３で減圧された冷媒は、低圧の気液二相状態となって（図中Ｄ点）、蒸発器１４に流入する。蒸発器１４を通過した冷媒は、過熱されたガス状態となって（図中Ｅ点）、アキュムレータ１５を通過した後に圧縮機１１に吸入される。また、凝縮器１２を通過してバイパス流路２０に流入した冷媒は、第２絞り装置２１に流入する。第２絞り装置２１で減圧された冷媒は、低圧の気液二相状態となって（図中Ｆ点）、内部熱交換器３０に流入する。内部熱交換器３０を通過した冷媒は、気液二相状態のまま（図中Ｇ点）、圧縮機１１に吸入される。 [High-pressure suppression operation mode]
FIG. 3 is a Mollier diagram of the refrigeration cycle in the high-pressure suppression operation mode of the air-conditioning apparatus according to Embodiment 1.
In the refrigeration cycle 1 in the high-pressure suppression operation mode, as shown in FIG. 3, the refrigerant discharged from the compressor 11 is in a high-pressure gas state (point A in the figure) and flows into the condenser 12. The refrigerant that has passed through the condenser 12 enters a gas-liquid two-phase state (point B in the figure) and flows into the internal heat exchanger 30. The refrigerant that has passed through the internal heat exchanger 30 becomes a supercooled liquid state (point C in the figure) and flows into the first expansion device 13. The refrigerant decompressed by the first expansion device 13 enters a low-pressure gas-liquid two-phase state (point D in the figure) and flows into the evaporator 14. The refrigerant that has passed through the evaporator 14 is in a superheated gas state (point E in the figure), passes through the accumulator 15, and is then sucked into the compressor 11. In addition, the refrigerant that has passed through the condenser 12 and has flowed into the bypass flow path 20 flows into the second expansion device 21. The refrigerant decompressed by the second expansion device 21 enters a low-pressure gas-liquid two-phase state (point F in the figure) and flows into the internal heat exchanger 30. The refrigerant that has passed through the internal heat exchanger 30 is sucked into the compressor 11 in a gas-liquid two-phase state (point G in the figure).
　つまり、制御部５０は、第１絞り装置１３の開度を、凝縮器１２における過冷却度が付かない開度、つまり、凝縮器１２の出口において冷媒が気液二相状態となる開度に調節して、冷凍サイクル１の高圧側圧力が、所定の圧力以下となるように調節する。また、第１絞り装置１３に気液二相状態の冷媒が流入して制御性が悪化することを抑制するために、制御部５０は、第２絞り装置２１の開度を、内部熱交換器３０においてバイパス流路２０の第２絞り装置２１を通過した冷媒によって冷却されて第１絞り装置１３に流入する冷媒が、液冷媒となる開度に調節する。凝縮器１２の出口において冷媒が気液二相状態となると、冷凍サイクル１のアキュムレータ１５以外を流れる冷媒量が減少することとなって、アキュムレータ１５内に余剰な冷媒が溜まる。 That is, the control unit 50 sets the opening of the first expansion device 13 to an opening at which the degree of supercooling in the condenser 12 is not provided, that is, an opening at which the refrigerant enters a gas-liquid two-phase state at the outlet of the condenser 12. It adjusts and it adjusts so that the high voltage | pressure side pressure of the refrigerating cycle 1 may become below a predetermined pressure. Further, in order to prevent the controllability from deteriorating due to the refrigerant in the gas-liquid two-phase state flowing into the first expansion device 13, the control unit 50 sets the opening degree of the second expansion device 21 to the internal heat exchanger. 30, the refrigerant cooled by the refrigerant that has passed through the second expansion device 21 of the bypass channel 20 and flowing into the first expansion device 13 is adjusted to an opening degree that becomes a liquid refrigerant. When the refrigerant enters a gas-liquid two-phase state at the outlet of the condenser 12, the amount of refrigerant flowing other than the accumulator 15 of the refrigeration cycle 1 is reduced, and excess refrigerant accumulates in the accumulator 15.
［液戻り抑制運転モード］
　高圧抑制運転モードにおいて、アキュムレータ１５内に冷媒が溜まりすぎると、アキュムレータ１５に溜まっている冷凍機油が、冷媒で希釈されて低濃度となり、また、アキュムレータ１５から流出する液冷媒の量が増加するため、圧縮機１１の信頼性が低下する。冷凍機油は、圧縮機１１の各部の潤滑、圧縮機１１の圧縮部のシール等の機能を有する。そのため、制御部５０は、アキュムレータ１５内の冷媒量を推定し、アキュムレータ１５内の冷媒量が多くなりすぎる前に、液戻り抑制運転モードに移行する。アキュムレータ１５内の冷媒量の推定方法は、後述される。 [Liquid return suppression operation mode]
If the refrigerant is excessively accumulated in the accumulator 15 in the high-pressure suppression operation mode, the refrigerating machine oil accumulated in the accumulator 15 is diluted with the refrigerant to have a low concentration, and the amount of liquid refrigerant flowing out from the accumulator 15 increases. The reliability of the compressor 11 is reduced. The refrigeration oil has functions such as lubrication of each part of the compressor 11 and sealing of the compression part of the compressor 11. Therefore, the control unit 50 estimates the refrigerant amount in the accumulator 15 and shifts to the liquid return suppression operation mode before the refrigerant amount in the accumulator 15 becomes too large. A method for estimating the amount of refrigerant in the accumulator 15 will be described later.
　制御部５０は、液戻り抑制運転モードに移行して、第２絞り装置２１の開度を、内部熱交換器３０の出口において冷媒がガス状態（過熱されたガス状態）となる開度に調節する。つまり、制御部５０は、アキュムレータ１５内の冷媒量が多い場合に、アキュムレータ１５内の冷媒量が少ない場合と比較して、第２絞り装置２１の開度を狭くして、バイパス流路２０を介して圧縮機１１に流入する液冷媒の量を減少させる。 The control unit 50 shifts to the liquid return suppression operation mode, and adjusts the opening degree of the second expansion device 21 to an opening degree at which the refrigerant is in a gas state (overheated gas state) at the outlet of the internal heat exchanger 30. To do. That is, the control unit 50 reduces the opening of the second expansion device 21 when the amount of refrigerant in the accumulator 15 is large, compared with the case where the amount of refrigerant in the accumulator 15 is small, The amount of liquid refrigerant flowing into the compressor 11 is reduced.
　図４は、冷媒の流速と液膜の厚さとの関係を説明するための図である。
　また、制御部５０は、それでもなお、アキュムレータ１５内の冷媒量が多すぎると判断される場合に、圧縮機１１の周波数を低下させ、第１絞り装置１３の開度を、蒸発器１４の出口において冷媒が過熱ガス状態とならない程度の開度に調節する。つまり、制御部５０は、アキュムレータ１５内の冷媒量が多い場合に、アキュムレータ１５内の冷媒量が少ない場合と比較して、圧縮機１１の周波数を低下させて、アキュムレータ１５に流入する液冷媒の量を減少させる。図４に示されるように、圧縮機１１の周波数が低くなると、冷媒の流速が低下して、冷媒が気液二相状態となる箇所に生じるせん断力が低減されることとなるため、冷媒が形成する液膜の厚さが厚くなる。そのため、蒸発器１４に貯留される冷媒量が増加して、アキュムレータ１５に流入する液冷媒の量が減少することとなる。 FIG. 4 is a diagram for explaining the relationship between the flow rate of the refrigerant and the thickness of the liquid film.
In addition, the control unit 50 still reduces the frequency of the compressor 11 and determines the opening degree of the first expansion device 13 to the outlet of the evaporator 14 when it is determined that the amount of refrigerant in the accumulator 15 is too large. In step 1, the opening is adjusted to such an extent that the refrigerant does not enter the superheated gas state. In other words, the control unit 50 reduces the frequency of the compressor 11 when the refrigerant amount in the accumulator 15 is large, compared with the case where the refrigerant amount in the accumulator 15 is small, and the liquid refrigerant flowing into the accumulator 15. Reduce the amount. As shown in FIG. 4, when the frequency of the compressor 11 is lowered, the flow rate of the refrigerant is reduced, and the shearing force generated at the location where the refrigerant is in a gas-liquid two-phase state is reduced. The thickness of the liquid film to be formed increases. Therefore, the amount of refrigerant stored in the evaporator 14 increases, and the amount of liquid refrigerant flowing into the accumulator 15 decreases.
（アキュムレータ内の冷媒量の推定方法）
　まず、制御部５０は、内部熱交換器出口温度センサー５３の検知結果から内部熱交換器３０の出口における冷媒の温度を取得する。 (Method for estimating the amount of refrigerant in the accumulator)
First, the control unit 50 acquires the temperature of the refrigerant at the outlet of the internal heat exchanger 30 from the detection result of the internal heat exchanger outlet temperature sensor 53.
　次に、制御部５０は、吐出圧力センサー５１の検知結果から内部熱交換器３０の出口における冷媒の圧力を取得する。吐出圧力センサー５１の検知結果に換えて、凝縮器１２の冷媒が二相状態となる箇所の冷媒の温度を検知する温度センサーの検知結果が用いられ、その温度センサーの検知結果から求まる飽和圧力が取得されてもよい。また、凝縮器１２が冷媒循環回路１０の冷媒と水回路４０の水とを熱交換させるものである場合には、冷凍サイクル１の凝縮温度と凝縮器１２から流出する水の温度とがほぼ等しい値になるため、吐出圧力センサー５１の検知結果に換えて、凝縮器１２から流出する水の温度を検知する温度センサーの検知結果が用いられ、その温度センサーの検知結果から求まる飽和圧力が取得されてもよい。 Next, the control unit 50 acquires the refrigerant pressure at the outlet of the internal heat exchanger 30 from the detection result of the discharge pressure sensor 51. Instead of the detection result of the discharge pressure sensor 51, the detection result of the temperature sensor that detects the temperature of the refrigerant at the location where the refrigerant of the condenser 12 is in a two-phase state is used, and the saturation pressure obtained from the detection result of the temperature sensor is May be acquired. When the condenser 12 exchanges heat between the refrigerant in the refrigerant circuit 10 and the water in the water circuit 40, the condensation temperature of the refrigeration cycle 1 and the temperature of water flowing out of the condenser 12 are substantially equal. Therefore, instead of the detection result of the discharge pressure sensor 51, the detection result of the temperature sensor that detects the temperature of the water flowing out of the condenser 12 is used, and the saturation pressure obtained from the detection result of the temperature sensor is acquired. May be.
　次に、制御部５０は、吸入圧力センサー５２の検知結果から圧縮機１１の吸入側の冷媒の圧力を取得する。吸入圧力センサー５２の検知結果に換えて、蒸発器１４の冷媒が二相状態となる箇所の冷媒の温度を検知する温度センサーの検知結果が用いられ、その温度センサーの検知結果から求まる飽和圧力が取得されてもよい。また、アキュムレータ１５内に冷媒が常に存在する場合には、アキュムレータ１５の出口における冷媒が気液二相状態となるため、吸入圧力センサー５２の検知結果に換えて、アキュムレータ１５の出口における冷媒の温度を検知する温度センサーの検知結果が用いられ、その温度センサーの検知結果から求まる飽和圧力が取得されてもよい。 Next, the control unit 50 acquires the refrigerant pressure on the suction side of the compressor 11 from the detection result of the suction pressure sensor 52. Instead of the detection result of the suction pressure sensor 52, the detection result of the temperature sensor that detects the temperature of the refrigerant at the location where the refrigerant of the evaporator 14 is in a two-phase state is used, and the saturation pressure obtained from the detection result of the temperature sensor is May be acquired. When the refrigerant is always present in the accumulator 15, the refrigerant at the outlet of the accumulator 15 is in a gas-liquid two-phase state. Therefore, instead of the detection result of the suction pressure sensor 52, the temperature of the refrigerant at the outlet of the accumulator 15. The detection result of the temperature sensor for detecting the temperature sensor may be used, and the saturation pressure obtained from the detection result of the temperature sensor may be acquired.
　次に、制御部５０は、内部熱交換器３０における交換熱量Ｑａを推定する。熱交換器の交換熱量Ｑは、一般に、伝熱面積をＡ、熱伝達率をＫ、温度差をΔＴ、とすると、以下の式（１）によって表される。伝熱面積Ａは、内部熱交換器３０の仕様から定まる。温度差ΔＴは、内部熱交換器３０の出口における冷媒の温度と、圧縮機１１の吸入側の冷媒の圧力から求まる飽和温度と、から定まる。 Next, the control unit 50 estimates the exchange heat quantity Qa in the internal heat exchanger 30. The heat exchange amount Q of the heat exchanger is generally expressed by the following equation (1), where A is the heat transfer area, K is the heat transfer coefficient, and ΔT is the temperature difference. The heat transfer area A is determined from the specifications of the internal heat exchanger 30. The temperature difference ΔT is determined from the refrigerant temperature at the outlet of the internal heat exchanger 30 and the saturation temperature obtained from the refrigerant pressure on the suction side of the compressor 11.
　［数１］
　Ｑ＝Ａ×Ｋ×ΔＴ　　　　　　　　　　　　　　　　　　・・・（１） [Equation 1]
Q = A × K × ΔT (1)
　また、熱伝達率Ｋは、レイノルズ数Ｒｅに比例する。レイノルズ数Ｒｅは、一般に、流速をｕ、代表直径をｄ、動粘性係数をν、とすると、以下の式（２）によって表される。内部熱交換器３０では、冷媒循環回路１０の凝縮器１２を通過した冷媒と、バイパス流路２０の第２絞り装置２１を通過した冷媒と、が熱交換するため、冷媒循環回路１０の冷媒循環量Ｇｒａと、バイパス流路２０の冷媒循環量Ｇｒｂと、予め取得されたレイノルズ数Ｒｅと内部熱交換器３０の特性との関係と、を用いて熱伝達率Ｋを推定することができる。冷媒循環回路１０の冷媒循環量Ｇｒａは、圧縮機１１の吸入側の冷媒の圧力と、圧縮機１１の周波数ｆと、から推定でき、冷媒の密度をρｓ、圧縮機１１のストロークボリュームをＶ、圧縮機１１の体積効率をηｖ、とすると、以下の式（３）によって表される。また、バイパス流路２０の冷媒循環量Ｇｒｂは、第２絞り装置２１の開度から求まる第２絞り装置２１のＣｖ値と、冷媒の第２絞り装置２１を通過する前後の差圧ΔＰと、から推定でき、冷媒の比重をＧ、係数をＣ、とすると、以下の式（４）によって表される。 Also, the heat transfer coefficient K is proportional to the Reynolds number Re. The Reynolds number Re is generally expressed by the following equation (2), where u is a flow velocity, d is a representative diameter, and v is a kinematic viscosity coefficient. In the internal heat exchanger 30, heat is exchanged between the refrigerant that has passed through the condenser 12 of the refrigerant circulation circuit 10 and the refrigerant that has passed through the second expansion device 21 of the bypass flow path 20, so that the refrigerant circulation of the refrigerant circulation circuit 10 The heat transfer coefficient K can be estimated using the amount Gra, the refrigerant circulation amount Grab of the bypass passage 20, and the relationship between the Reynolds number Re acquired in advance and the characteristics of the internal heat exchanger 30. The refrigerant circulation amount Gra of the refrigerant circuit 10 can be estimated from the refrigerant pressure on the suction side of the compressor 11 and the frequency f of the compressor 11, the refrigerant density is ρs, the stroke volume of the compressor 11 is V, When the volume efficiency of the compressor 11 is ηv, it is expressed by the following equation (3). In addition, the refrigerant circulation amount Grb in the bypass flow path 20 includes the Cv value of the second expansion device 21 obtained from the opening of the second expansion device 21, the differential pressure ΔP before and after passing through the second expansion device 21 of the refrigerant, If the specific gravity of the refrigerant is G and the coefficient is C, it is represented by the following equation (4).
　［数２］
　Ｒｅ＝ｕ×ｄ／ν　　　　　　　　　　　　　　　　　　・・・（２） [Equation 2]
Re = u × d / ν (2)
　［数３］
　Ｇｒａ＝ρｓ×Ｖ×ｆ×ηｖ　　　　　　　　　　　　　・・・（３） [Equation 3]
Gra = ρs × V × f × ηv (3)
　［数４］
　Ｇｒｂ＝Ｃ×Ｃｖ×（ΔＰ／Ｇ）０．５　　　　　　　　　・・・（４） [Equation 4]
Grb = C × Cv × (ΔP / G) 0.5 (4)
　次に、制御部５０は、凝縮器１２の出口における冷媒のクオリティ（乾き度）を推定する。クオリティ（乾き度）は、内部熱交換器３０の出口における冷媒の圧力と、凝縮器１２の出口における冷媒のエンタルピと、から推定することができる。凝縮器１２の出口における冷媒のエンタルピｈ２は、内部熱交換器３０の出口における冷媒のエンタルピｈ１と、内部熱交換器３０の交換熱量Ｑａと、冷媒循環回路１０の冷媒循環量Ｇｒａと、から推定でき、以下の式（５）によって表される。内部熱交換器３０の出口における冷媒のエンタルピｈ１は、内部熱交換器３０の出口における冷媒の圧力及び温度から求まる。 Next, the control unit 50 estimates the quality (dryness) of the refrigerant at the outlet of the condenser 12. The quality (dryness) can be estimated from the refrigerant pressure at the outlet of the internal heat exchanger 30 and the refrigerant enthalpy at the outlet of the condenser 12. The refrigerant enthalpy h2 at the outlet of the condenser 12 is estimated from the refrigerant enthalpy h1 at the outlet of the internal heat exchanger 30, the exchange heat quantity Qa of the internal heat exchanger 30, and the refrigerant circulation quantity Gra of the refrigerant circulation circuit 10. And is represented by the following equation (5). The enthalpy h1 of the refrigerant at the outlet of the internal heat exchanger 30 is obtained from the pressure and temperature of the refrigerant at the outlet of the internal heat exchanger 30.
　［数５］
　ｈ２＝ｈ１＋Ｑａ／Ｇｒａ　　　　　　　　　　　　　　・・・（５） [Equation 5]
h2 = h1 + Qa / Gra (5)
　次に、制御部５０は、凝縮器１２の冷媒量を推定する。凝縮器１２の冷媒量は、凝縮器１２における液冷媒量とガス冷媒量との比率から推定することができる。凝縮器１２における液冷媒量とガス冷媒量との比率は、内部熱交換器３０の出口における冷媒の圧力と、凝縮器１２の出口における冷媒のクオリティ（乾き度）と、から推定することができる。内部熱交換器３０の出口における冷媒の圧力と、凝縮器１２の出口における冷媒のクオリティ（乾き度）と、凝縮器１２の冷媒量と、の関係が予め取得され、凝縮器１２の冷媒量が、その関係を用いて推定されるとよい。 Next, the control unit 50 estimates the amount of refrigerant in the condenser 12. The refrigerant quantity of the condenser 12 can be estimated from the ratio of the liquid refrigerant quantity and the gas refrigerant quantity in the condenser 12. The ratio between the liquid refrigerant amount and the gas refrigerant amount in the condenser 12 can be estimated from the refrigerant pressure at the outlet of the internal heat exchanger 30 and the refrigerant quality (dryness) at the outlet of the condenser 12. . The relationship between the refrigerant pressure at the outlet of the internal heat exchanger 30, the quality (dryness) of the refrigerant at the outlet of the condenser 12, and the refrigerant quantity of the condenser 12 is acquired in advance, and the refrigerant quantity of the condenser 12 is It may be estimated using the relationship.
　次に、制御部５０は、蒸発器１４における交換熱量Ｑｂを推定する。式（１）において、伝熱面積Ａは、蒸発器１４の仕様から定まる。温度差ΔＴは、吸入圧力センサー５２の検知結果から求まる飽和温度と、外気温度センサー５４の検知結果から取得される外気温度と、から定まる。また、蒸発器１４の熱交換性能は、空気側（フィン側）の性能に大きく依存するため、熱伝達率Ｋは、フィンの熱交換性能から推定されるとよい。フィンの熱交換性能は、ファンからの送風量に比例するため、ファンからの送風量と、伝熱特性と、の関係が予め取得され、熱伝達率Ｋが、その関係を用いて推定されるとよい。ファンからの送風量は、ファンの回転数から換算できる。 Next, the control unit 50 estimates the exchange heat quantity Qb in the evaporator 14. In equation (1), the heat transfer area A is determined from the specifications of the evaporator 14. The temperature difference ΔT is determined from the saturation temperature obtained from the detection result of the suction pressure sensor 52 and the outside air temperature acquired from the detection result of the outside air temperature sensor 54. Moreover, since the heat exchange performance of the evaporator 14 greatly depends on the performance on the air side (fin side), the heat transfer coefficient K may be estimated from the heat exchange performance of the fins. Since the heat exchange performance of the fin is proportional to the amount of air blown from the fan, the relationship between the amount of air blown from the fan and the heat transfer characteristics is acquired in advance, and the heat transfer coefficient K is estimated using the relationship. Good. The amount of air blown from the fan can be converted from the rotational speed of the fan.
　次に、制御部５０は、蒸発器１４の出口における冷媒のクオリティ（乾き度）を推定する。クオリティ（乾き度）は、圧縮機１１の吸入側の冷媒の圧力と、蒸発器１４の出口における冷媒のエンタルピと、から推定することができる。蒸発器１４の出口における冷媒のエンタルピｈ３は、内部熱交換器３０の出口における冷媒のエンタルピｈ１と、蒸発器１４の交換熱量Ｑｂと、冷媒循環回路１０の冷媒循環量Ｇｒａと、から推定でき、以下の式（６）によって表される。 Next, the control unit 50 estimates the quality (dryness) of the refrigerant at the outlet of the evaporator 14. The quality (dryness) can be estimated from the refrigerant pressure on the suction side of the compressor 11 and the refrigerant enthalpy at the outlet of the evaporator 14. The refrigerant enthalpy h3 at the outlet of the evaporator 14 can be estimated from the refrigerant enthalpy h1 at the outlet of the internal heat exchanger 30, the exchange heat quantity Qb of the evaporator 14, and the refrigerant circulation amount Gra of the refrigerant circuit 10. It is represented by the following formula (6).
　［数６］
　ｈ３＝ｈ１＋Ｑｂ／Ｇｒａ　　　　　　　　　　　　　　・・・（６） [Equation 6]
h3 = h1 + Qb / Gra (6)
　次に、制御部５０は、蒸発器１４の冷媒量を推定する。蒸発器１４の冷媒量は、蒸発器１４における液冷媒量とガス冷媒量との比率から推定することができる。蒸発器１４における液冷媒量とガス冷媒量との比率は、圧縮機１１の吸入側の冷媒の圧力と、蒸発器１４の出口における冷媒のクオリティ（乾き度）と、から推定することができる。圧縮機１１の吸入側の冷媒の圧力と、蒸発器１４の出口における冷媒のクオリティ（乾き度）と、蒸発器１４の冷媒量と、の関係が予め取得され、蒸発器１４の冷媒量が、その関係を用いて推定されるとよい。 Next, the control unit 50 estimates the amount of refrigerant in the evaporator 14. The refrigerant amount of the evaporator 14 can be estimated from the ratio of the liquid refrigerant amount and the gas refrigerant amount in the evaporator 14. The ratio between the liquid refrigerant amount and the gas refrigerant amount in the evaporator 14 can be estimated from the refrigerant pressure on the suction side of the compressor 11 and the quality (dryness) of the refrigerant at the outlet of the evaporator 14. The relationship between the refrigerant pressure on the suction side of the compressor 11, the refrigerant quality (dryness) at the outlet of the evaporator 14, and the refrigerant amount of the evaporator 14 is acquired in advance, and the refrigerant amount of the evaporator 14 is It is good to estimate using the relationship.
　次に、制御部５０は、アキュムレータ１５内の冷媒量を推定する。アキュムレータ１５内の冷媒量は、冷凍サイクル１に封入される冷媒量から、凝縮器１２の冷媒量と、蒸発器１４の冷媒量と、を引くことによって推定することができる。つまり、アキュムレータ１５内の冷媒量は、冷凍サイクル１における冷媒量分布に基づいて、推定することができる。 Next, the control unit 50 estimates the amount of refrigerant in the accumulator 15. The amount of refrigerant in the accumulator 15 can be estimated by subtracting the amount of refrigerant in the condenser 12 and the amount of refrigerant in the evaporator 14 from the amount of refrigerant enclosed in the refrigeration cycle 1. That is, the refrigerant amount in the accumulator 15 can be estimated based on the refrigerant amount distribution in the refrigeration cycle 1.
＜空気調和装置の作用＞
　空気調和装置１００では、制御部５０が、アキュムレータ１５内に冷媒が溜まりすぎると、液戻り抑制運転モードに移行して、第２絞り装置２１の開度を、内部熱交換器３０の出口において冷媒がガス状態（過熱されたガス状態）となる開度に調節する。そのため、圧縮機１１に吸入される前に、アキュムレータ１５から流出する液冷媒と、内部熱交換器３０を通過したガス状態（過熱されたガス状態）の冷媒と、を混合して、圧縮機１１に戻る液冷媒の量を低減することが可能であるため、圧縮機１１の信頼性が向上される。 <Operation of air conditioner>
In the air conditioner 100, when the control unit 50 accumulates too much refrigerant in the accumulator 15, the control unit 50 shifts to the liquid return suppression operation mode, and the opening degree of the second expansion device 21 is changed to the refrigerant at the outlet of the internal heat exchanger 30. Is adjusted to an opening degree at which becomes a gas state (overheated gas state). Therefore, before being sucked into the compressor 11, the liquid refrigerant flowing out from the accumulator 15 and the refrigerant in a gas state (overheated gas state) that has passed through the internal heat exchanger 30 are mixed together, and the compressor 11 is mixed. Since it is possible to reduce the quantity of the liquid refrigerant which returns, the reliability of the compressor 11 is improved.
　また、空気調和装置１００では、制御部５０が、それでもなお、アキュムレータ１５内の冷媒量が多すぎると判断される場合に、圧縮機１１の周波数を低下させる。そのため、蒸発器１４に貯留される冷媒量を増加させて、圧縮機１１に戻る液冷媒の量を低減することが可能であるため、圧縮機１１の信頼性が向上される。 Also, in the air conditioner 100, the control unit 50 reduces the frequency of the compressor 11 when it is still determined that the amount of refrigerant in the accumulator 15 is too large. Therefore, it is possible to increase the amount of refrigerant stored in the evaporator 14 and reduce the amount of liquid refrigerant that returns to the compressor 11, so that the reliability of the compressor 11 is improved.
実施の形態２．
　以下に、実施の形態２に係る空気調和装置について説明する。
　なお、以下では、実施の形態１と重複又は類似する説明については、適宜簡略化又は省略している。
＜空気調和装置の構成＞
　図５は、実施の形態２に係る空気調和装置の、構成を説明するための図である。
　図５に示されるように、凝縮器１２は、冷媒循環回路１０の冷媒と水回路４０の水とを熱交換させる。水回路４０は、ポンプ４１を駆動源として、室内機の熱交換器等に温水を供給するものである。 Embodiment 2. FIG.
Below, the air conditioning apparatus which concerns on Embodiment 2 is demonstrated.
Note that, in the following, descriptions that overlap or are similar to those of the first embodiment are appropriately simplified or omitted.
<Configuration of air conditioner>
FIG. 5 is a diagram for explaining the configuration of the air-conditioning apparatus according to Embodiment 2.
As shown in FIG. 5, the condenser 12 exchanges heat between the refrigerant in the refrigerant circuit 10 and the water in the water circuit 40. The water circuit 40 supplies hot water to a heat exchanger or the like of the indoor unit using the pump 41 as a drive source.
　制御部５０には、圧縮機１１、第１絞り装置１３、第２絞り装置２１、ポンプ４１、圧縮機１１の吐出側の冷媒の圧力を検知する吐出圧力センサー５１、圧縮機１１の吸入側の冷媒の圧力を検知する吸入圧力センサー５２、内部熱交換器３０の出口側の冷媒の温度を検知する内部熱交換器出口温度センサー５３、外気温度を検知する外気温度センサー５４、圧縮機１１の吐出側の冷媒の温度を検知する吐出温度センサー５５、凝縮器１２に流入する水の温度を検知する入水温度センサー５６、凝縮器１２から流出する水の温度を検知する出湯温度センサー５７等が接続される。 The control unit 50 includes a compressor 11, a first throttle device 13, a second throttle device 21, a pump 41, a discharge pressure sensor 51 that detects the pressure of refrigerant on the discharge side of the compressor 11, and a suction side of the compressor 11. An intake pressure sensor 52 that detects the pressure of the refrigerant, an internal heat exchanger outlet temperature sensor 53 that detects the temperature of the refrigerant on the outlet side of the internal heat exchanger 30, an outside air temperature sensor 54 that detects the outside air temperature, and the discharge of the compressor 11 A discharge temperature sensor 55 for detecting the temperature of the refrigerant on the side, an incoming water temperature sensor 56 for detecting the temperature of the water flowing into the condenser 12, a hot water temperature sensor 57 for detecting the temperature of the water flowing out of the condenser 12, and the like are connected. The
＜空気調和装置の動作＞
（アキュムレータ内の冷媒量の推定方法）
　まず、制御部５０は、吐出圧力センサー５１の検知結果及び吐出温度センサー５５の検知結果から圧縮機１１の吐出側の冷媒の圧力及び温度を取得する。また、制御部５０は、入水温度センサー５６の検知結果及び出湯温度センサー５７の検知結果から凝縮器１２に流入する水の温度Ｔｗｉｎ及び凝縮器１２から流出する水の温度Ｔｗｏｕｔを取得する。 <Operation of air conditioner>
(Method for estimating the amount of refrigerant in the accumulator)
First, the control unit 50 acquires the pressure and temperature of the refrigerant on the discharge side of the compressor 11 from the detection result of the discharge pressure sensor 51 and the detection result of the discharge temperature sensor 55. Further, the control unit 50 acquires the temperature Twin of water flowing into the condenser 12 and the temperature Twout of water flowing out of the condenser 12 from the detection result of the incoming water temperature sensor 56 and the detection result of the hot water temperature sensor 57.
　次に、制御部５０は、凝縮器１２における交換熱量Ｑｃを推定する。凝縮器１２における交換熱量Ｑｃは、凝縮器１２に流入する水の温度Ｔｗｉｎと凝縮器１２から流出する水の温度Ｔｗｏｕｔとの差と、水流量Ｇｗから推定でき、水の比熱をＣｐｗ、水の密度をρｗ、とすると、以下の式（７）によって表される。水流量Ｇｗは、ポンプ４１の回転数から求まる。また、水の比熱Ｃｐｗ及び水の密度ρｗは、水の温度から求まる。 Next, the control unit 50 estimates the exchange heat quantity Qc in the condenser 12. The exchange heat quantity Qc in the condenser 12 can be estimated from the difference between the temperature Twin of the water flowing into the condenser 12 and the temperature Twout of the water flowing out of the condenser 12 and the water flow rate Gw. The specific heat of the water is Cpw, If the density is ρw, it is expressed by the following equation (7). The water flow rate Gw is obtained from the rotational speed of the pump 41. Further, the specific heat Cpw of water and the density ρw of water are obtained from the temperature of the water.
　［数７］
　Ｑｃ＝（Ｔｗｉｎ－Ｔｗｏｕｔ）×Ｇｗ×Ｃｐｗ×ρｗ　　・・・（７） [Equation 7]
Qc = (Twin−Twout) × Gw × Cpw × ρw (7)
　次に、制御部５０は、凝縮器１２の出口における冷媒のクオリティ（乾き度）を推定する。クオリティ（乾き度）は、圧縮機１１の吐出側の冷媒の圧力と、凝縮器１２の出口における冷媒のエンタルピと、から推定することができる。凝縮器１２の出口における冷媒のエンタルピｈ２は、圧縮機１１の吐出側における冷媒のエンタルピｈ０と、凝縮器１２の交換熱量Ｑｃと、冷媒循環回路１０の冷媒循環量Ｇｒａと、から推定でき、以下の式（８）によって表される。圧縮機１１の吐出側における冷媒のエンタルピｈ０は、圧縮機１１の吐出側の冷媒の圧力及び温度から求まる。 Next, the control unit 50 estimates the quality (dryness) of the refrigerant at the outlet of the condenser 12. The quality (dryness) can be estimated from the refrigerant pressure on the discharge side of the compressor 11 and the refrigerant enthalpy at the outlet of the condenser 12. The refrigerant enthalpy h2 at the outlet of the condenser 12 can be estimated from the refrigerant enthalpy h0 on the discharge side of the compressor 11, the exchange heat amount Qc of the condenser 12, and the refrigerant circulation amount Gra of the refrigerant circuit 10, and the following (8) The refrigerant enthalpy h0 on the discharge side of the compressor 11 is obtained from the pressure and temperature of the refrigerant on the discharge side of the compressor 11.
　［数８］
　ｈ２＝ｈ０―Ｑｃ／Ｇｒａ　　　　　　　　　・・・（８） [Equation 8]
h2 = h0−Qc / Gra (8)
　次に、制御部５０は、凝縮器１２の冷媒量を推定する。凝縮器１２の冷媒量は、凝縮器１２における液冷媒量とガス冷媒量との比率から推定することができる。凝縮器１２における液冷媒量とガス冷媒量との比率は、圧縮機１１の吐出側の冷媒の圧力と、凝縮器１２の出口における冷媒のクオリティ（乾き度）と、から推定することができる。圧縮機１１の吐出側の冷媒の圧力と、凝縮器１２の出口における冷媒のクオリティ（乾き度）と、凝縮器１２の冷媒量と、の関係が予め取得され、凝縮器１２の冷媒量が、その関係を用いて推定されるとよい。 Next, the control unit 50 estimates the amount of refrigerant in the condenser 12. The refrigerant quantity of the condenser 12 can be estimated from the ratio of the liquid refrigerant quantity and the gas refrigerant quantity in the condenser 12. The ratio between the liquid refrigerant amount and the gas refrigerant amount in the condenser 12 can be estimated from the refrigerant pressure on the discharge side of the compressor 11 and the quality (dryness) of the refrigerant at the outlet of the condenser 12. The relationship between the refrigerant pressure on the discharge side of the compressor 11, the quality (dryness) of the refrigerant at the outlet of the condenser 12, and the refrigerant amount of the condenser 12 is acquired in advance, and the refrigerant amount of the condenser 12 is It is good to estimate using the relationship.
　次に、制御部５０は、蒸発器１４における交換熱量Ｑｂを推定する。式（１）において、伝熱面積Ａは、蒸発器１４の仕様から定まる。温度差ΔＴは、吸入圧力センサー５２の検知結果から求まる飽和温度と、外気温度センサー５４の検知結果から取得される外気温度と、から定まる。また、蒸発器１４の熱交換性能は、空気側（フィン側）の性能に大きく依存するため、熱伝達率Ｋは、フィンの熱交換性能から推定されるとよい。フィンの熱交換性能は、ファンからの送風量に比例するため、ファンからの送風量と、伝熱特性と、の関係が予め取得され、熱伝達率Ｋが、その関係を用いて推定されるとよい。ファンからの送風量は、ファンの回転数から換算できる。 Next, the control unit 50 estimates the exchange heat quantity Qb in the evaporator 14. In equation (1), the heat transfer area A is determined from the specifications of the evaporator 14. The temperature difference ΔT is determined from the saturation temperature obtained from the detection result of the suction pressure sensor 52 and the outside air temperature acquired from the detection result of the outside air temperature sensor 54. Moreover, since the heat exchange performance of the evaporator 14 greatly depends on the performance on the air side (fin side), the heat transfer coefficient K may be estimated from the heat exchange performance of the fins. Since the heat exchange performance of the fin is proportional to the amount of air blown from the fan, the relationship between the amount of air blown from the fan and the heat transfer characteristics is acquired in advance, and the heat transfer coefficient K is estimated using the relationship. Good. The amount of air blown from the fan can be converted from the rotational speed of the fan.
　次に、制御部５０は、蒸発器１４の出口における冷媒のクオリティ（乾き度）を推定する。クオリティ（乾き度）は、圧縮機１１の吸入側の冷媒の圧力と、蒸発器１４の出口における冷媒のエンタルピと、から推定することができる。蒸発器１４の出口における冷媒のエンタルピｈ３は、内部熱交換器３０の出口における冷媒のエンタルピｈ１と、蒸発器１４の交換熱量Ｑｂと、冷媒循環回路１０の冷媒循環量Ｇｒａと、から推定でき、以下の式（９）によって表される。 Next, the control unit 50 estimates the quality (dryness) of the refrigerant at the outlet of the evaporator 14. The quality (dryness) can be estimated from the refrigerant pressure on the suction side of the compressor 11 and the refrigerant enthalpy at the outlet of the evaporator 14. The refrigerant enthalpy h3 at the outlet of the evaporator 14 can be estimated from the refrigerant enthalpy h1 at the outlet of the internal heat exchanger 30, the exchange heat quantity Qb of the evaporator 14, and the refrigerant circulation amount Gra of the refrigerant circuit 10. It is represented by the following formula (9).
　［数９］
　ｈ３＝ｈ１＋Ｑｂ／Ｇｒａ　　　　　　　　　・・・（９） [Equation 9]
h3 = h1 + Qb / Gra (9)
　次に、制御部５０は、蒸発器１４の冷媒量を推定する。蒸発器１４の冷媒量は、蒸発器１４における液冷媒量とガス冷媒量との比率から推定することができる。蒸発器１４における液冷媒量とガス冷媒量との比率は、圧縮機１１の吸入側の冷媒の圧力と、蒸発器１４の出口における冷媒のクオリティ（乾き度）と、から推定することができる。圧縮機１１の吸入側の冷媒の圧力と、蒸発器１４の出口における冷媒のクオリティ（乾き度）と、蒸発器１４の冷媒量と、の関係が予め取得され、蒸発器１４の冷媒量が、その関係を用いて推定されるとよい。 Next, the control unit 50 estimates the amount of refrigerant in the evaporator 14. The refrigerant amount of the evaporator 14 can be estimated from the ratio of the liquid refrigerant amount and the gas refrigerant amount in the evaporator 14. The ratio between the liquid refrigerant amount and the gas refrigerant amount in the evaporator 14 can be estimated from the refrigerant pressure on the suction side of the compressor 11 and the quality (dryness) of the refrigerant at the outlet of the evaporator 14. The relationship between the refrigerant pressure on the suction side of the compressor 11, the refrigerant quality (dryness) at the outlet of the evaporator 14, and the refrigerant amount of the evaporator 14 is acquired in advance, and the refrigerant amount of the evaporator 14 is It is good to estimate using the relationship.
　次に、制御部５０は、アキュムレータ１５内の冷媒量を推定する。アキュムレータ１５内の冷媒量は、冷凍サイクル１に封入される冷媒量から、凝縮器１２の冷媒量と、蒸発器１４の冷媒量と、を引くことによって推定することができる。つまり、アキュムレータ１５内の冷媒量は、冷凍サイクル１における冷媒量分布に基づいて、推定することができる。 Next, the control unit 50 estimates the amount of refrigerant in the accumulator 15. The amount of refrigerant in the accumulator 15 can be estimated by subtracting the amount of refrigerant in the condenser 12 and the amount of refrigerant in the evaporator 14 from the amount of refrigerant enclosed in the refrigeration cycle 1. That is, the refrigerant amount in the accumulator 15 can be estimated based on the refrigerant amount distribution in the refrigeration cycle 1.
＜空気調和装置の作用＞
　空気調和装置１００では、制御部５０が、凝縮器１２の出口における冷媒のエンタルピｈ２を、圧縮機１１の吐出側における冷媒のエンタルピｈ０と、凝縮器１２の交換熱量Ｑｃと、冷媒循環回路１０の冷媒循環量Ｇｒａと、から推定する。そのため、制御部５０が、凝縮器１２の出口における冷媒のエンタルピｈ２を、内部熱交換器３０の出口における冷媒のエンタルピｈ１と、内部熱交換器３０の交換熱量Ｑａと、冷媒循環回路１０の冷媒循環量Ｇｒａと、から推定する場合と比較して、凝縮器１２の冷媒量の推定が高精度化されることとなって、圧縮機１１に戻る液冷媒の量を低減することの確実性が更に向上されて、圧縮機１１の信頼性が更に向上される。 <Operation of air conditioner>
In the air conditioner 100, the control unit 50 controls the refrigerant enthalpy h <b> 2 at the outlet of the condenser 12, the refrigerant enthalpy h <b> 0 on the discharge side of the compressor 11, the exchange heat quantity Qc of the condenser 12, and the refrigerant circulation circuit 10. It is estimated from the refrigerant circulation amount Gra. Therefore, the control unit 50 determines the refrigerant enthalpy h2 at the outlet of the condenser 12, the refrigerant enthalpy h1 at the outlet of the internal heat exchanger 30, the exchange heat quantity Qa of the internal heat exchanger 30, and the refrigerant of the refrigerant circulation circuit 10. Compared to the case of estimating from the circulation amount Gra, the estimation of the refrigerant amount of the condenser 12 is improved, and the certainty of reducing the amount of liquid refrigerant returning to the compressor 11 is improved. This further improves the reliability of the compressor 11.
実施の形態３．
　以下に、実施の形態３に係る空気調和装置について説明する。
　なお、以下では、実施の形態１及び実施の形態２と重複又は類似する説明については、適宜簡略化又は省略している。また、以下では、実施の形態３に係る空気調和装置が、実施の形態１に係る空気調和装置と同様のものである場合を説明しているが、実施の形態２に係る空気調和装置と同様のものであってもよい。
＜空気調和装置の構成＞
　図６は、実施の形態３に係る空気調和装置の、構成を説明するための図である。
　図６に示されるように、バイパス流路２０の下流側は、圧縮機１１の、冷媒を圧縮する圧縮部に接続される。 Embodiment 3 FIG.
Below, the air conditioning apparatus which concerns on Embodiment 3 is demonstrated.
In the following description, descriptions that overlap or are similar to those in Embodiments 1 and 2 are simplified or omitted as appropriate. Moreover, although the case where the air conditioning apparatus which concerns on Embodiment 3 is the same as the air conditioning apparatus which concerns on Embodiment 1 below is demonstrated, it is the same as the air conditioning apparatus which concerns on Embodiment 2. It may be.
<Configuration of air conditioner>
FIG. 6 is a diagram for explaining the configuration of the air-conditioning apparatus according to Embodiment 3.
As shown in FIG. 6, the downstream side of the bypass flow path 20 is connected to a compressor of the compressor 11 that compresses the refrigerant.
＜空気調和装置の作用＞
　空気調和装置１００では、バイパス流路２０の下流側が、圧縮機１１の圧縮部に接続されて、バイパス流路２０の冷媒が、圧縮機１１の圧縮部に直接流入するため、バイパス流路２０の下流側が、冷媒循環回路１０のアキュムレータ１５と圧縮機１１との間の部分に接続されて、バイパス流路２０の冷媒が、圧縮機１１の吸入ポートから圧縮機１１に流入する場合と比較して、圧縮機１１のシェル底に溜まる液冷媒の量が低減される。そのため、圧縮機１１のシェル底に溜まっている潤滑油が液冷媒によって希釈されることが抑制されて、圧縮機１１の信頼性が更に向上される。また、バイパス流路２０の冷媒のクオリティ（乾き度）を低くすることが可能となる。 <Operation of air conditioner>
In the air conditioner 100, the downstream side of the bypass channel 20 is connected to the compression unit of the compressor 11, and the refrigerant in the bypass channel 20 flows directly into the compression unit of the compressor 11. Compared to the case where the downstream side is connected to the portion between the accumulator 15 and the compressor 11 of the refrigerant circulation circuit 10 and the refrigerant in the bypass flow path 20 flows into the compressor 11 from the suction port of the compressor 11. The amount of liquid refrigerant that accumulates at the shell bottom of the compressor 11 is reduced. Therefore, it is suppressed that the lubricating oil collected on the shell bottom of the compressor 11 is diluted with the liquid refrigerant, and the reliability of the compressor 11 is further improved. In addition, the quality (dryness) of the refrigerant in the bypass channel 20 can be lowered.
実施の形態４．
　以下に、実施の形態４に係る空気調和装置について説明する。
　なお、以下では、実施の形態１～実施の形態３と重複又は類似する説明については、適宜簡略化又は省略している。
＜空気調和装置の構成＞
　空気調和装置１００の構成は、実施の形態１～実施の形態３に示される空気調和装置１００の構成と同様である。冷凍サイクル１の冷媒として、ＨＦＯ１２３４ｙｆ又はＨＦＯ１２３４ｚｅが用いられる。 Embodiment 4 FIG.
The air conditioner according to Embodiment 4 will be described below.
In the following description, descriptions overlapping or similar to those in Embodiments 1 to 3 are appropriately simplified or omitted.
<Configuration of air conditioner>
The configuration of the air conditioner 100 is the same as the configuration of the air conditioner 100 shown in the first to third embodiments. As the refrigerant of the refrigeration cycle 1, HFO1234yf or HFO1234ze is used.
＜空気調和装置の作用＞
　図７は、冷媒がＨＦＯ１２３４ｙｆ又はＨＦＯ１２３４ｚｅである場合のモリエル線図である。
　図７に示されるように、冷媒がＨＦＯ１２３４ｙｆ又はＨＦＯ１２３４ｚｅである場合には、冷媒がＲ４１０Ａ等である場合と比較して、圧縮機１１の吐出側における冷媒の温度が低くなり、圧縮機１１に過度の液冷媒が戻ると、圧縮機１１の吸入側の冷媒に加えて圧縮機１１の吐出側の冷媒が気液二相状態となって（つまり、圧縮行程の全域で気液二相状態となって）、圧縮機１１に過度の負荷が掛かりやすくなる。そのため、冷媒がＲ４１０Ａ等である場合と比較して、空気調和装置１００が、実施の形態１～実施の形態３に示される動作を行うことの重要度が高くなって、圧縮機１１の信頼性が向上されるとの効果が顕著となる。 <Operation of air conditioner>
FIG. 7 is a Mollier diagram in the case where the refrigerant is HFO1234yf or HFO1234ze.
As shown in FIG. 7, when the refrigerant is HFO1234yf or HFO1234ze, the refrigerant temperature on the discharge side of the compressor 11 is lower than that when the refrigerant is R410A or the like, and excessively flows into the compressor 11. When the liquid refrigerant returns, the refrigerant on the discharge side of the compressor 11 is in a gas-liquid two-phase state in addition to the refrigerant on the suction side of the compressor 11 (that is, the gas-liquid two-phase state is set over the entire compression stroke). And an excessive load is easily applied to the compressor 11. Therefore, compared with the case where the refrigerant is R410A or the like, it is more important for the air conditioner 100 to perform the operations shown in the first to third embodiments, and the reliability of the compressor 11 is improved. The effect of improving is remarkable.
　以上、実施の形態１～実施の形態４について説明したが、本発明は各実施の形態の説明に限定されない。例えば、各実施の形態の全て又は一部を組み合わせることも可能である。 Although the first to fourth embodiments have been described above, the present invention is not limited to the description of each embodiment. For example, it is possible to combine all or some of the embodiments.
　１　冷凍サイクル、１０　冷媒循環回路、１１　圧縮機、１２　凝縮器、１３　第１絞り装置、１４　蒸発器、１５　アキュムレータ、２０　バイパス流路、２１　第２絞り装置、３０　内部熱交換器、４０　水回路、４１　ポンプ、５０　制御部、５１　吐出圧力センサー、５２　吸入圧力センサー、５３　内部熱交換器出口温度センサー、５４　外気温度センサー、５５　吐出温度センサー、５６　入水温度センサー、５７　出湯温度センサー、１００　空気調和装置。 1 Refrigeration cycle, 10 Refrigerant circulation circuit, 11 Compressor, 12 Condenser, 13 1st expansion device, 14 Evaporator, 15 Accumulator, 20 Bypass channel, 21 2nd expansion device, 30 Internal heat exchanger, 40 Water circuit , 41 pump, 50 control unit, 51 discharge pressure sensor, 52 suction pressure sensor, 53 internal heat exchanger outlet temperature sensor, 54 outside air temperature sensor, 55 discharge temperature sensor, 56 incoming water temperature sensor, 57 hot water temperature sensor, 100 air conditioning apparatus.

Claims (11)

  1. 　圧縮機と、凝縮器と、第１絞り装置と、蒸発器と、アキュムレータと、が環状に接続された冷媒循環回路と、
    　途中部に第２絞り装置が接続され、前記冷媒循環回路の前記凝縮器と前記第１絞り装置との間の部分を流れる冷媒を前記圧縮機にバイパスするバイパス流路と、
    　前記冷媒循環回路の前記凝縮器と前記第１絞り装置との間の部分を流れる冷媒と、前記バイパス流路の前記第２絞り装置を通過した冷媒と、を熱交換させる内部熱交換器と、
    　前記アキュムレータ内の冷媒量に応じて、前記バイパス流路を介して前記圧縮機に流入する液冷媒の量を変化させる制御手段と、を備えた冷凍サイクル装置。     A refrigerant circulation circuit in which a compressor, a condenser, a first expansion device, an evaporator, and an accumulator are connected in an annular shape;
    A bypass passage that is connected to a second throttle device in the middle and bypasses the refrigerant that flows through a portion of the refrigerant circuit between the condenser and the first throttle device to the compressor;
    An internal heat exchanger for exchanging heat between the refrigerant flowing through the portion of the refrigerant circulation circuit between the condenser and the first expansion device and the refrigerant that has passed through the second expansion device of the bypass flow path;
    A refrigeration cycle apparatus comprising: control means for changing the amount of liquid refrigerant flowing into the compressor via the bypass flow path according to the amount of refrigerant in the accumulator.
  2. 　前記制御手段は、前記アキュムレータ内の冷媒量が多い場合に、前記アキュムレータ内の冷媒量が少ない場合と比較して、前記第２絞り装置の開度を狭くする、請求項１に記載の冷凍サイクル装置。 2. The refrigeration cycle according to claim 1, wherein when the amount of refrigerant in the accumulator is large, the control means narrows the opening of the second expansion device as compared with a case where the amount of refrigerant in the accumulator is small. apparatus.
  3. 　前記制御手段は、前記アキュムレータ内の冷媒量に応じて、前記アキュムレータに流入する液冷媒の量を変化させる、請求項１又は２に記載の冷凍サイクル装置。 The refrigeration cycle apparatus according to claim 1 or 2, wherein the control means changes the amount of liquid refrigerant flowing into the accumulator according to the amount of refrigerant in the accumulator.
  4. 　前記制御手段は、前記アキュムレータ内の冷媒量が多い場合に、前記アキュムレータ内の冷媒量が少ない場合と比較して、前記圧縮機の周波数を低くする、請求項３に記載の冷凍サイクル装置。 The refrigeration cycle apparatus according to claim 3, wherein the control means lowers the frequency of the compressor when the amount of refrigerant in the accumulator is large compared to when the amount of refrigerant in the accumulator is small.
  5. 　前記制御手段は、少なくとも前記凝縮器及び前記蒸発器の冷媒量の推定結果に基づいて、前記アキュムレータ内の冷媒量を推定する、請求項１～４のいずれか一項に記載の冷凍サイクル装置。 The refrigeration cycle apparatus according to any one of claims 1 to 4, wherein the control means estimates a refrigerant amount in the accumulator based on at least a result of estimating a refrigerant amount of the condenser and the evaporator.
  6. 　前記凝縮器は、前記冷媒循環回路の冷媒を水と熱交換させ、
    　前記制御手段は、前記圧縮機から吐出される冷媒の温度と、前記凝縮器に流入する水の温度及び前記凝縮器から流出する水の温度と、に基づいて、前記凝縮器の冷媒量を推定する、請求項５に記載の冷凍サイクル装置。     The condenser causes the refrigerant in the refrigerant circuit to exchange heat with water,
    The control means estimates the amount of refrigerant in the condenser based on the temperature of refrigerant discharged from the compressor, the temperature of water flowing into the condenser, and the temperature of water flowing out of the condenser. The refrigeration cycle apparatus according to claim 5.
  7. 　前記バイパス流路の下流側は、前記冷媒循環回路の前記アキュムレータと前記圧縮機との間の部分に接続された、請求項１～６のいずれか一項に記載の冷凍サイクル装置。 The refrigeration cycle apparatus according to any one of claims 1 to 6, wherein a downstream side of the bypass flow path is connected to a portion of the refrigerant circulation circuit between the accumulator and the compressor.
  8. 　前記バイパス流路の下流側は、前記圧縮機の圧縮部に接続された、請求項１～６のいずれか一項に記載の冷凍サイクル装置。 The refrigeration cycle apparatus according to any one of claims 1 to 6, wherein a downstream side of the bypass channel is connected to a compression unit of the compressor.
  9. 　冷媒として、ＨＦＯ１２３４ｙｆ又はＨＦＯ１２３４ｚｅが用いられた、請求項１～８のいずれか一項に記載の冷凍サイクル装置。 The refrigeration cycle apparatus according to any one of claims 1 to 8, wherein HFO1234yf or HFO1234ze is used as the refrigerant.
  10. 　請求項１～９のいずれか一項に記載の冷凍サイクル装置である、空気調和装置。 An air conditioner, which is the refrigeration cycle apparatus according to any one of claims 1 to 9.
  11. 　圧縮機と、凝縮器と、第１絞り装置と、蒸発器と、アキュムレータと、が環状に接続された冷媒循環回路と、途中部に第２絞り装置が接続され、前記冷媒循環回路の前記凝縮器と前記第１絞り装置との間の部分を流れる冷媒を前記圧縮機にバイパスするバイパス流路と、前記冷媒循環回路の前記凝縮器と前記第１絞り装置との間の部分を流れる冷媒と、前記バイパス流路の前記第２絞り装置を通過した冷媒と、を熱交換させる内部熱交換器と、を備えた冷凍サイクル装置の制御方法であって、
    　前記アキュムレータ内の冷媒量に応じて、前記バイパス流路を介して前記圧縮機に流入する液冷媒の量を変化させる、冷凍サイクル装置の制御方法。     A refrigerant circulation circuit in which a compressor, a condenser, a first expansion device, an evaporator, and an accumulator are annularly connected, and a second expansion device is connected in the middle, and the condensation of the refrigerant circulation circuit A bypass flow path for bypassing the refrigerant flowing through the portion between the condenser and the first throttling device to the compressor, and the refrigerant flowing through the portion between the condenser and the first throttling device of the refrigerant circulation circuit; An internal heat exchanger for exchanging heat between the refrigerant that has passed through the second expansion device of the bypass flow path, and a control method for a refrigeration cycle apparatus comprising:
    The control method of the refrigerating-cycle apparatus which changes the quantity of the liquid refrigerant | coolant which flows in into the said compressor via the said bypass flow path according to the refrigerant | coolant amount in the said accumulator.
PCT/JP2014/066913 2014-06-25 2014-06-25 Refrigeration-cycle device, air conditioner, and method for controlling refrigeration cycle device WO2015198431A1 (en)

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