WO2024069896A1 - Climatiseur - Google Patents

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Publication number
WO2024069896A1
WO2024069896A1 PCT/JP2022/036586 JP2022036586W WO2024069896A1 WO 2024069896 A1 WO2024069896 A1 WO 2024069896A1 JP 2022036586 W JP2022036586 W JP 2022036586W WO 2024069896 A1 WO2024069896 A1 WO 2024069896A1
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Prior art keywords
compressor
refrigerant
temperature
discharge
discharge temperature
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PCT/JP2022/036586
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English (en)
Japanese (ja)
Inventor
修平 多田
宏治 内藤
政▲眠▼ 李
Original Assignee
日立ジョンソンコントロールズ空調株式会社
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Priority to PCT/JP2022/036586 priority Critical patent/WO2024069896A1/fr
Publication of WO2024069896A1 publication Critical patent/WO2024069896A1/fr

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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

Definitions

  • the present invention relates to an air conditioner that uses a non-azeotropic refrigerant mixture.
  • HFOs known to have low GWP include 2,3,3,3-tetrafluoropropene (HFO1234yf), (E)-1,3,3,3-tetrafluoropropene (HFO1234ze(E)), and trifluoroethene (HFO1123).
  • HFO1234yf and HFO1234ze(E) are refrigerants with lower operating pressures and heat capacities than conventional refrigerants such as R410A.
  • HFO1123 is known to cause disproportionation reactions depending on the concentration and temperature. HFOs alone are currently unable to achieve the refrigerant properties required for air conditioners and other devices. For the time being, it is expected that mixed refrigerants in which HFOs are mixed with other refrigerant components will be developed.
  • Mixed refrigerants in which HFOs are mixed with other refrigerant components can adjust the refrigerant properties and lower the GWP by adjusting the mixing ratio of the HFOs.
  • such mixed refrigerants are not necessarily azeotropic or pseudo-azeotropic mixed refrigerants, and can be non-azeotropic mixed refrigerants.
  • mixing HFO1234yf or HFO1234ze(E) with R32 or R410A results in a non-azeotropic mixed refrigerant.
  • Patent Document 1 describes a technology that prevents liquid backflow into the compressor while suppressing an increase in the compressor discharge temperature.
  • the compressor frequency, the opening of the pressure reducing device, and the rotation speeds of the first and second fans are controlled so that the dryness fraction when the compressor sucks in the refrigerant is 1.0 or higher.
  • Patent Document 1 the dryness of the refrigerant when sucked into the compressor is set to 1.0 or more to prevent liquid backflow into the compressor.
  • Patent Document 1 assumes the use of a pseudo-azeotropic refrigerant mixture.
  • the gas-liquid ratio varies greatly depending on the pressure and temperature. Therefore, in the method of controlling on the suction side of the compressor as in Patent Document 1, when a non-azeotropic refrigerant mixture is used, there is a possibility that poor lubrication of the compressor cannot be sufficiently suppressed and that the allowable range of the dryness and superheat of the refrigerant may be significantly limited.
  • the present invention aims to provide an air conditioner that appropriately prevents poor lubrication of the compressor in a refrigerant circuit that uses a non-azeotropic refrigerant mixture.
  • the air conditioner of the present invention is an air conditioner equipped with a refrigerant circuit in which a compressor, a condenser, a pressure reducer, and an evaporator are connected in sequence by refrigerant piping to circulate the refrigerant, the refrigerant is a non-azeotropic refrigerant mixture composed of two or more refrigerant components, and the discharge temperature of the compressor is controlled to a temperature higher than the saturation temperature of the highest boiling point component, which has the highest boiling point among the refrigerant components, at the discharge pressure of the compressor.
  • the present invention provides an air conditioner that appropriately prevents poor lubrication of the compressor in a refrigerant circuit that uses a non-azeotropic refrigerant mixture.
  • FIG. 1 is a system diagram showing a refrigeration cycle of an air conditioner according to an embodiment of the present invention.
  • FIG. 2 is a diagram showing an example of the relationship between the pressure and the saturation temperature of a non-azeotropic refrigerant mixture and a refrigerant component.
  • FIG. 4 is a diagram showing measurement results of the relationship between the discharge temperature of a compressor and the viscosity of refrigeration oil. 4 is a flowchart showing control of a discharge temperature of a compressor.
  • FIG. 4 is a diagram showing a control range of a discharge temperature of a compressor.
  • 5 is a flowchart showing an application example of control of a discharge temperature of a compressor. 5 is a flowchart showing an application example of control of a discharge temperature of a compressor. 5 is a flowchart showing an application example of control of a discharge temperature of a compressor. 5 is a flowchart showing an application example of control of a discharge temperature of a compressor. 5 is a flowchart showing an application example of control
  • the air conditioner according to this embodiment is equipped with a refrigerant circuit that circulates a refrigerant.
  • the refrigerant circuit is formed by connecting a compressor that compresses the refrigerant, a condenser that condenses the refrigerant, a pressure reducer that reduces the pressure of the refrigerant, and an evaporator that evaporates the refrigerant in this order with refrigerant piping.
  • a non-azeotropic refrigerant mixture composed of two or more refrigerant components is used as the refrigerant.
  • the compressor discharge temperature is controlled to a temperature higher than the saturation temperature at the compressor discharge pressure of the highest boiling point component, which has the highest boiling point among the refrigerant components that make up the non-azeotropic refrigerant mixture.
  • the compressor discharge temperature is controlled by one or more of the opening degree of the expansion valve, the rotation speed of the compressor, the rotation speed of the outdoor blower, and the opening degree of the injection valve.
  • the high-boiling components do not completely evaporate in the evaporator and tend to be sucked into the compressor in liquid form.
  • liquid refrigerant components dissolve more easily into the refrigeration oil sealed in the compressor.
  • the viscosity of the refrigeration oil decreases, causing poor lubrication of the compressor.
  • the sliding parts of the compressor experience oil film breakage, seizure and wear, making stable operation of the compressor difficult and reducing the product reliability of the air conditioner.
  • FIG. 1 is a system diagram showing a refrigeration cycle of an air conditioner according to an embodiment of the present invention.
  • the solid arrows indicate the direction in which the refrigerant flows during cooling operation
  • the dashed arrows indicate the direction in which the refrigerant flows during heating operation.
  • the air conditioner 1 includes an outdoor unit 10 and an indoor unit 30.
  • the outdoor unit 10 and the indoor unit 30 are connected to each other by a main refrigerant circuit via a gas connection pipe 2 and a liquid connection pipe 3.
  • the outdoor unit 10 and the indoor unit 30 are connected in a one-to-one relationship, but multiple outdoor units may be connected to one indoor unit, or multiple indoor units may be connected to one outdoor unit. Also, multiple indoor units may be connected to multiple outdoor units.
  • the outdoor unit 10 is equipped with a compressor 11, a four-way valve 12, an outdoor heat exchanger 13, an outdoor blower 14, an outdoor expansion valve 15, an accumulator 20, a gas refrigerant piping 16, a compressor suction piping 17, a compressor discharge piping 18, an injection piping 19, and an injection valve 21. These devices, together with the refrigerant piping and the indoor unit 30, form a refrigerant circuit.
  • One port of the four-way valve 12 is connected to the inlet side of the accumulator 20 via a gas refrigerant pipe 16.
  • the other ports are connected to the discharge side of the compressor 11, the outdoor heat exchanger 13, and the gas connection pipe 2 via refrigerant pipes.
  • the outlet side of the accumulator 20 is connected to the suction side of the compressor 11 via a compressor suction pipe 17.
  • the discharge side of the compressor 11 is connected to the four-way valve 12 via a compressor discharge pipe 18.
  • the compressor 11 is a device that compresses the refrigerant, compressing the gaseous refrigerant that is sucked in and discharging high-temperature, high-pressure gas refrigerant.
  • the compressor 11 is a hermetic electric compressor with an injection port.
  • the rotation speed of the compressor 11 can be variably controlled by an inverter.
  • the compressor 11 can be any suitable compressor, such as a scroll type, piston type, rotary type, screw type, centrifugal type, etc.
  • the four-way valve 12 is a valve that can switch the flow direction of the refrigerant in the refrigerant circuit.
  • the flow direction of the refrigerant discharged from the compressor 11 is switched by the four-way valve 12 depending on the operating mode of heating or cooling.
  • the outdoor heat exchanger 13 is a heat exchanger that exchanges heat between the refrigerant and the outside air.
  • the outdoor heat exchanger 13 functions as a condenser during cooling operation and as an evaporator during heating operation.
  • the outdoor blower 14 is installed near the outdoor heat exchanger 13 and blows outside air to the outdoor heat exchanger 13.
  • the rotation speed of the fan of the outdoor blower 14 can be variably controlled by an inverter.
  • the outdoor heat exchanger 13 is connected to the indoor unit 30 via a refrigerant pipe and a liquid connection pipe 3.
  • An outdoor expansion valve 15 is installed in the refrigerant pipe between the outdoor heat exchanger 13 and the liquid connection pipe 3.
  • the outdoor expansion valve 15 acts as a pressure reducer to reduce the pressure of the refrigerant, and expands the liquid refrigerant condensed in the indoor heat exchanger 31 during heating operation by reducing the pressure.
  • the outdoor expansion valve 15 can adjust its opening continuously or intermittently, and has the function of adjusting the flow rate of the refrigerant.
  • An injection pipe 19 is connected to the refrigerant pipe between the outdoor heat exchanger 13 and the liquid connection pipe 3, closer to the indoor unit 30 than the outdoor expansion valve 15.
  • the other end of the injection pipe 19 is connected to an injection port on the suction side of the compressor 11.
  • the injection pipe 19 is configured to connect to the compressor 11, bypassing the condenser and evaporator.
  • An injection valve 21 is installed in the injection pipe 19.
  • the injection valve 21 can adjust its opening continuously or intermittently, and is provided so as to be able to open and close the injection pipe 19.
  • the injection valve 21 can adjust the flow rate of the refrigerant injected into the suction side of the compressor 11, and the distribution ratio of the refrigerant between the main refrigerant circuit and the injection pipe 19.
  • the accumulator 20 separates the refrigerant into gas and liquid and temporarily stores the liquid refrigerant separated from the gas refrigerant.
  • the dryness of the gas refrigerant is adjusted by the accumulator 20 before it is sucked into the compressor 11. By adjusting the dryness, liquid return to the compressor 11 is suppressed.
  • the indoor unit 30 is equipped with an indoor heat exchanger 31, an indoor blower 32, and an indoor expansion valve 33. These devices, together with the refrigerant piping and the outdoor unit 10, form a refrigerant circuit.
  • the indoor heat exchanger 31 is a heat exchanger that exchanges heat between the refrigerant and the indoor air.
  • the indoor heat exchanger 31 acts as an evaporator during cooling operation and as a condenser during heating operation.
  • the indoor blower 32 is installed near the indoor heat exchanger 31 and blows indoor air to the indoor heat exchanger 31.
  • the indoor heat exchanger 31 is connected to the outdoor unit 10 via a refrigerant pipe and a liquid connection pipe 3.
  • An indoor expansion valve 33 is installed in the refrigerant pipe between the indoor heat exchanger 31 and the liquid connection pipe 3.
  • the indoor expansion valve 33 acts as a pressure reducer to reduce the pressure of the refrigerant, and expands the liquid refrigerant condensed in the outdoor heat exchanger 13 during cooling operation.
  • the opening of the indoor expansion valve 33 can be adjusted continuously or intermittently, and it has the function of adjusting the flow rate of the refrigerant.
  • a check valve 22 is installed in the gas connection pipe 2.
  • a check valve 23 is installed in the liquid connection pipe 3. These check valves 22, 23 are opened after the air conditioner 1 is installed.
  • the compressor suction pipe 17 is provided with a suction side pressure sensor 24 and a suction side temperature sensor 25.
  • the suction side pressure sensor 24 is a sensor that measures the pressure of the refrigerant being sucked into the compressor 11.
  • the suction side temperature sensor 25 is a sensor that measures the temperature of the refrigerant being sucked into the compressor 11.
  • a discharge side pressure sensor 26 and a discharge side temperature sensor 27 are installed in the compressor discharge pipe 18.
  • the discharge side pressure sensor 26 is a sensor that measures the pressure of the refrigerant discharged from the compressor 11.
  • the discharge side temperature sensor 27 is a sensor that measures the temperature of the refrigerant discharged from the compressor 11.
  • the discharge side temperature sensor 27 may measure the wall temperature of the compressor chamber in order to accurately measure the temperature of the discharged refrigerant after compression even during transient periods such as when the air conditioner is started.
  • a compression chamber is formed at the top of the inside of the compressor chamber and is made up of a fixed scroll and an orbiting scroll.
  • the compressed high-temperature, high-pressure refrigerant is discharged from near the center of the fixed scroll, passes near the top of the compressor chamber, passes around the motor, and is discharged into the refrigerant circuit from a discharge pipe provided on the side of the chamber. Therefore, by measuring the wall temperature near the top of the compressor chamber, the refrigerant temperature can be detected more accurately.
  • a temperature sensor for estimating pressure may be provided in the middle of the heat exchanger. Because it is a non-azeotropic refrigerant, the dew point and boiling point are different at the same pressure, and the accuracy is inferior to that of a pressure sensor, but the pressure estimate based on the temperature in the middle of the heat exchanger can be used for control.
  • the air conditioner 1 is equipped with a control device (not shown).
  • the control device is a microcomputer or the like, and is composed of a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc.
  • the control device is connected to the suction side pressure sensor 24, the discharge side pressure sensor 26, and the discharge side temperature sensor 27 via communication lines (not shown).
  • the control device receives measurement signals from each sensor.
  • the control device controls the various devices provided in the air conditioner 1 by having the CPU execute a program read into the RAM. Based on the measurement results from each sensor, the control device controls the rotation speed of the compressor 11, the opening of the indoor expansion valve 33, the opening of the outdoor expansion valve 15, the rotation speed of the outdoor blower 14, the opening of the injection valve 21, etc., so that the discharge temperature of the compressor 11 meets specified conditions.
  • the cooling operation of the air conditioner 1 will be described.
  • the solid arrows indicate the direction in which the refrigerant flows during cooling operation.
  • the four-way valve 12 connects the discharge side of the compressor 11 to the outdoor heat exchanger 13, and connects the indoor heat exchanger 31 to the suction side of the accumulator 20.
  • the compressor 11 compresses the gas refrigerant and discharges high-temperature, high-pressure gas refrigerant.
  • the high-temperature, high-pressure gas refrigerant flows into the outdoor heat exchanger 13 via the four-way valve 12.
  • the high-temperature, high-pressure gas refrigerant is cooled and condensed by heat exchange with outside air, becoming high-pressure liquid refrigerant.
  • the high-pressure liquid refrigerant is reduced in pressure by the indoor expansion valve 33 and expands into a low-temperature, low-pressure, two-phase gas-liquid refrigerant.
  • the low-temperature, low-pressure, two-phase gas-liquid refrigerant flows into the indoor heat exchanger 31.
  • the low-temperature, low-pressure two-phase gas-liquid refrigerant is heated by heat exchange with the indoor air in the indoor heat exchanger 31, becoming a low-temperature, low-pressure gas refrigerant.
  • the indoor air cooled by the heat exchange is blown into the room as cold air.
  • the low-pressure gas refrigerant returns to the outdoor unit 10 from the indoor unit 30 through the gas connection pipe 2, and flows into the accumulator 20 via the four-way valve 12.
  • the low-pressure gas refrigerant is separated from the remaining liquid refrigerant and adjusted to a dryness within a specified range.
  • the low-pressure gas refrigerant is sucked into the compressor 11 and compressed again. Cooling operation is performed through this cycle.
  • the heating operation of the air conditioner 1 will be described.
  • the dashed arrows indicate the direction in which the refrigerant flows during heating operation.
  • the four-way valve 12 connects the discharge side of the compressor 11 to the indoor heat exchanger 31, and connects the outdoor heat exchanger 13 to the suction side of the accumulator 20.
  • the compressor 11 compresses the gas refrigerant and discharges high-temperature, high-pressure gas refrigerant.
  • the high-temperature, high-pressure gas refrigerant flows into the indoor heat exchanger 31 via the four-way valve 12.
  • the indoor heat exchanger 31 the high-temperature, high-pressure gas refrigerant is cooled and condensed into high-pressure liquid refrigerant by heat exchange with the indoor air.
  • the indoor air heated by the heat exchange is blown into the room as warm air.
  • the high-pressure liquid refrigerant returns to the outdoor unit 10 from the indoor unit 30 through the liquid connection piping 3, where it is decompressed and expanded by the outdoor expansion valve 15 to become a low-pressure two-phase gas-liquid refrigerant.
  • the low-pressure two-phase gas-liquid refrigerant flows into the outdoor heat exchanger 13.
  • the low-pressure gas-liquid two-phase refrigerant is heated by heat exchange with outside air in the outdoor heat exchanger 13, becoming a low-pressure gas refrigerant.
  • the low-pressure gas refrigerant flows into the accumulator 20 via the four-way valve 12.
  • the low-pressure gas refrigerant is separated from the remaining liquid refrigerant and adjusted to a dryness within a specified range.
  • the low-pressure gas refrigerant is sucked into the compressor 11 and compressed again. Heating operation is performed through this cycle.
  • the injection valve 21 When the injection valve 21 is closed during cooling or heating operation, the entire amount of liquid refrigerant cooled in the outdoor heat exchanger 13 flows into the indoor heat exchanger 31. On the other hand, when the opening degree of the injection valve 21 is adjusted, a portion of the liquid refrigerant cooled in the outdoor heat exchanger 13 flows into the indoor heat exchanger 31, and the remaining liquid refrigerant bypasses the main refrigerant circuit via the injection pipe 19 and is injected into the injection port on the suction side of the compressor 11.
  • the injection valve 21 is controlled according to the discharge temperature and discharge superheat of the compressor 11, the outside air temperature during heating operation, etc. Injecting refrigerant through the injection pipe 19 reduces the specific enthalpy of the refrigerant sucked into the compressor 11 from the main refrigerant circuit. Therefore, by injecting the refrigerant, the discharge temperature and discharge superheat of the compressor 11 can be suppressed to a temperature at which the compressor 11 will not burn or deteriorate thermally.
  • Figure 2 shows an example of the relationship between pressure and saturation temperature for non-azeotropic refrigerant mixtures and refrigerant components.
  • the horizontal axis shows absolute pressure [MPa] and the vertical axis shows saturation temperature [°C].
  • the dashed line shows data for R466A, which corresponds to a non-azeotropic refrigerant mixture.
  • the solid line shows data for R13I1, which corresponds to the highest boiling point component.
  • R466A is 49% by mass R32, 11.5% by mass R125, and 39.5% by mass R13I1.
  • the higher the refrigerant pressure the higher the saturation temperature. Below the saturation temperature, some or most of the refrigerant is in a liquid state. Refrigerant in a liquid state easily dissolves into refrigeration oil. When a refrigerant dissolves into refrigeration oil, the viscosity of the liquid refrigerant alone is extremely small compared to the viscosity of the refrigeration oil. Therefore, when the refrigerant is below the saturation temperature, the refrigerant is more likely to dissolve into the refrigeration oil, and the viscosity of the refrigeration oil is more likely to decrease. In the case of non-azeotropic refrigerant mixtures, the saturation temperature of each refrigerant component varies greatly. Therefore, the amount of dissolution into refrigeration oil also varies greatly for each refrigerant component.
  • high-boiling point components such as R13I1 dissolve in greater amounts into refrigeration oil and have a greater impact on reducing the viscosity of the refrigeration oil. Furthermore, if there is a difference in the amount of dissolution into the refrigeration oil, not only will the viscosity of the refrigeration oil decrease, but the gas-liquid ratio will also differ, resulting in an imbalance in the composition of the gas refrigerant. When using a non-azeotropic refrigerant mixture, it is important to suppress the dissolution of high-boiling point components into the refrigeration oil.
  • FIG. 3 is a diagram showing the measurement results of the relationship between the discharge temperature of the compressor and the viscosity of the refrigeration oil.
  • the discharge pressure of the compressor was controlled to 1.8 MPa, and the discharge temperature was changed under a constant pressure to measure the viscosity of the refrigeration oil inside the compressor at each discharge temperature.
  • the horizontal axis indicates the discharge temperature [°C] of the compressor, and the vertical axis indicates the viscosity [mPa ⁇ s] of the refrigeration oil.
  • the dashed line indicates the measurement result using R410A and polyvinyl ether oil (PVE), which correspond to a pseudo-azeotropic refrigerant mixture.
  • PVE polyvinyl ether oil
  • the solid line indicates the measurement result using R466A and polyol ester oil (POE), which correspond to a non-azeotropic refrigerant mixture.
  • POE polyol ester oil
  • the dashed line indicates the saturation temperature of R13I1.
  • the maximum viscosity of the refrigeration oil is near the saturation temperature of the high boiling point component. Therefore, by controlling the discharge temperature of the compressor to a temperature higher than the saturation temperature of the highest boiling point component, which has the highest boiling point among the refrigerant components that make up the non-azeotropic refrigerant mixture, the decrease in the viscosity of the refrigeration oil can be effectively suppressed.
  • FIG. 4 is a flowchart showing the control of the compressor discharge temperature.
  • the discharge temperature of the compressor 11 is controlled so as to be higher than the vicinity of the saturation temperature TsH of the highest boiling point component constituting the non-azeotropic refrigerant mixture at the current discharge pressure of the compressor 11, based on the saturation temperature TsH .
  • the saturation temperature means the highest temperature at which the temperature of the liquid at a certain pressure does not increase any more. Near the saturation temperature means a temperature difference from the saturation temperature in a range of 0° C. to 10° C.
  • the air conditioner 1 when the discharge temperature of the non-azeotropic refrigerant mixture on the discharge side of the compressor 11 is To [° C.] and the saturation temperature of the highest boiling point component constituting the non-azeotropic refrigerant mixture at the discharge pressure of the compressor 11 is Ts H [° C.], control is performed so that To > Ts H -10 is satisfied.
  • step S10 the current discharge pressure Pd of the mixed refrigerant and the current discharge temperature To of the mixed refrigerant are obtained.
  • the current discharge pressure Pd of the mixed refrigerant can be measured by the discharge pressure sensor 26 installed on the discharge side of the compressor 11. By measuring it on the discharge side, it is possible to accurately grasp the pressure at any time, including transient states.
  • the discharge side temperature sensor 27 may be installed in the compressor discharge pipe 18, inside the compressor 11, or on the surface of the compressor 11.
  • the discharge side temperature sensor 27 may directly measure the temperature of the refrigerant, or may measure the temperature of the wall surface of the chamber of the compressor 11, the wall surface of the casing, etc., as the refrigerant temperature.
  • the current discharge temperature To of the mixed refrigerant can be measured by a discharge side temperature sensor 27 installed on the discharge side of the compressor 11.
  • the current discharge temperature To of the mixed refrigerant may be estimated based on the condensation temperature of the mixed refrigerant.
  • the condensation temperature can be obtained using a temperature sensor installed in the middle or outlet side of the heat exchanger.
  • step S11 based on the current discharge pressure Pd of the mixed refrigerant, the saturation temperature TsH of the highest boiling point component at that discharge pressure is calculated (step S11).
  • the saturation temperature TsH of the highest boiling point component can be obtained based on the relationship between pressure and saturation temperature specific to each refrigerant component.
  • the relationship between pressure and saturation temperature is represented by a vapor pressure curve.
  • the saturation temperature for any current pressure can be obtained.
  • the relationship between the pressure and saturation temperature of the mixed refrigerant can be stored in advance in the memory unit of the control device as a data table or the like.
  • the current pressure of the highest boiling point component on the discharge side of compressor 11 can be determined based on the current discharge pressure Pd of the mixed refrigerant.
  • the composition of the non-azeotropic mixed refrigerant on the discharge side of compressor 11 can be considered to be equivalent to the initial composition sealed in the refrigerant circuit.
  • the current pressure of the highest boiling point component on the discharge side of compressor 11 can be calculated as a partial pressure relative to the initial composition.
  • the composition of the non-azeotropic refrigerant on the discharge side of the compressor 11 can also be estimated based on the difference between the initial saturation temperature of the non-azeotropic refrigerant and the current saturation temperature of the non-azeotropic refrigerant.
  • the initial saturation temperature can be a measured value measured in the initial state before dissolution into the refrigeration oil or deterioration of the refrigerant, or a theoretical value based on the refrigerant composition.
  • the current saturation temperature can be obtained using a temperature sensor installed in the middle or outlet side of the heat exchanger.
  • the current discharge temperature To of the mixed refrigerant is compared with a threshold value Th1 that is set based on the saturation temperature TsH of the highest boiling point component (step S12).
  • the threshold value Th1 is set to a value close to the saturation temperature TsH of the highest boiling point component constituting the non-azeotropic refrigerant mixture. It is preferable to set the threshold value Th1 to a value that is -10°C below the saturation temperature TsH of the highest boiling point component for each arbitrary current pressure.
  • step S12 If the comparison result shows that the current discharge temperature To of the mixed refrigerant exceeds the threshold value Th1 corresponding to the vicinity of the saturation temperature TsH of the highest boiling point component (step S12; NO), the discharge temperature of the compressor 11 is within the appropriate range, so the process returns to step S10.
  • step S12 when the comparison result shows that the current discharge temperature To of the mixed refrigerant is equal to or lower than the threshold value Th1 corresponding to the vicinity of the saturation temperature TsH of the highest boiling point component (step S12; YES), the discharge temperature of the compressor 11 is low, so the process proceeds to step S13.
  • control is performed to increase the discharge temperature of the compressor 11 (step S13).
  • the control for increasing the discharge temperature of the compressor 11 can be one or more of the following: control to reduce the opening of the indoor expansion valve 33 during cooling operation, control to reduce the opening of the outdoor expansion valve 15 during heating operation, control to increase the drive frequency of the compressor 11 to increase the rotation speed, control to increase the drive frequency of the outdoor blower 14 during cooling operation to decrease the rotation speed, and control to reduce the opening of the injection valve 21.
  • the refrigerant flow rate to the compressor 11 decreases, and the pressure ratio between the discharge pressure and the suction pressure increases, causing the discharge temperature of the compressor 11 to rise.
  • the rotation speed of the compressor 11 is increased, the discharge pressure of the compressor increases, causing the discharge temperature of the compressor 11 to rise.
  • the rotation speed of the outdoor blower 14 is reduced, the amount of heat exchanged in the outdoor heat exchanger 13 decreases, causing the discharge temperature of the compressor 11 to rise.
  • the compressor 11 can be controlled so that the pressure ratio between the discharge pressure and the suction pressure becomes a predetermined target value.
  • the compressor discharge temperature is controlled based on the saturation temperature of the highest boiling point component that constitutes the non-azeotropic refrigerant mixture, but the degree of superheat of the mixed refrigerant on the suction side of the compressor 11 may be 0 or more.
  • the saturation temperature of the non-azeotropic refrigerant mixture can be determined, for example, by the dew point method or the midpoint method.
  • the dryness may also be controlled without determining the degree of superheat.
  • the dryness of the mixed refrigerant on the suction side of the compressor 11 may be 1.0 or more, or less than 1.0. However, if a large amount of liquid refrigerant is drawn in, liquid compression can lead to damage to the orbiting scroll portion of the scroll compressor, so it is desirable to ensure that the dryness is at least 0.65.
  • One method of preventing refrigerant from dissolving into the refrigeration oil is to control the degree of superheat of the refrigerant drawn into the compressor to a specified range. This method may be adopted particularly in the case of a low-pressure chamber system in which the compressor chamber is filled with the drawn-in refrigerant. However, if the degree of suction superheat is controlled based on the saturation temperature of the high-boiling point components, the degree of superheat will be around 10 to 20 K. In that case, the discharge superheat of the compressed high-temperature, high-pressure refrigerant will be excessive, and the refrigerant discharge temperature will be high. Operation in this state is not appropriate as it will impair the reliability of the air conditioner's compressor.
  • a high-pressure chamber type scroll compressor or rotary compressor in which the inside of the compressor chamber is filled with compressed refrigerant.
  • the compression chamber volume of a scroll compressor or rotary compressor, and the number of cylinders of a rotary compressor are determined from the heating or cooling capacity required by the air conditioner, the amount of refrigerant circulating, and the compressor rotation speed.
  • the compressor discharge temperature is controlled based on the saturation temperature of the highest boiling point component that makes up the non-azeotropic refrigerant mixture, so the effects of high boiling point components that contribute greatly to the decrease in viscosity of the refrigeration oil can be directly suppressed.
  • the compressor discharge temperature is controlled based on the saturation temperature of the highest boiling point component that makes up the non-azeotropic refrigerant mixture, so the effects of high boiling point components that contribute greatly to the decrease in viscosity of the refrigeration oil can be directly suppressed.
  • the suction superheat or suction dryness as a basis, it is possible to effectively suppress the decrease in viscosity of the refrigeration oil and expand the allowable operating range for the overall superheat of the mixed refrigerant, etc.
  • the discharge side of the compressor is the part of the refrigerant circuit that becomes particularly hot. Therefore, by controlling the discharge side of the compressor, it is possible to ensure that the dissolution of the refrigerant into the refrigeration oil is suppressed throughout the entire refrigerant circuit and within the compressor, which requires lubrication. This ensures that seizure and wear on the sliding parts of the compressor are reduced while minimizing bias in the refrigerant composition caused by differences in the amount of dissolution.
  • Fig. 5 is a diagram showing the control range of the compressor discharge temperature.
  • the horizontal axis indicates the compressor discharge pressure [MPa]
  • the vertical axis indicates the temperature [°C] at the discharge side of the compressor.
  • the dashed line indicates the saturation temperature Ts of the non-azeotropic refrigerant mixture.
  • the dashed and dotted line indicates the saturation temperature TsH of the highest boiling point component constituting the non-azeotropic refrigerant mixture.
  • the solid line indicates the allowable lower limit To_min of the discharge temperature of the compressor 11.
  • the solid line indicates the allowable upper limit To_max of the discharge temperature of the compressor 11.
  • a numerical value close to the saturation temperature TsH of the highest boiling point component can be set as the allowable lower limit To_min of the compressor discharge temperature.
  • the compressor discharge temperature is controlled to be within a range equal to or greater than the allowable lower limit To_min and equal to or less than the allowable upper limit To_max according to the compressor discharge pressure.
  • the allowable lower limit To_min is preferably set to a value that is -10°C relative to the saturation temperature TsH of the highest boiling point component for each arbitrary current pressure.
  • the allowable lower limit To_min may also be set to a value that is -5°C or -3°C relative to the saturation temperature TsH of the highest boiling point component for each arbitrary current pressure.
  • a value of ⁇ 0°C may be set to control the temperature to be higher than the saturation temperature TsH of the highest boiling point component.
  • the allowable upper limit value To_max can be set to a value according to the heat resistance allowable temperature of the compressor 11. It is preferable to set the allowable upper limit value To_max to a value of 120°C, which corresponds to a general heat resistance allowable temperature, or a value less than 120°C that ensures a margin for the heat resistance allowable temperature, taking into account the heat resistance temperature of the resin material used inside the compressor.
  • Fig. 6 is a flowchart showing an application example of the control of the compressor discharge temperature.
  • Fig. 6 shows an example in which the control of the compressor discharge temperature based on the saturation temperature of the highest boiling point component constituting the non-azeotropic refrigerant mixture is executed as a measure against excessive fluctuations in the discharge temperature of the compressor 11 when the discharge temperature of the compressor 11 transiently increases or decreases.
  • the operation of the equipment can be controlled so that the discharge temperature of the compressor 11 does not exceed an allowable upper limit.
  • a value near the saturation temperature of the highest boiling point component constituting the non-azeotropic refrigerant mixture can be incorporated as the allowable lower limit of the discharge temperature of the compressor 11.
  • the discharge temperature of the compressor 11 rises, for example, when the discharge pressure of the compressor 11 increases, or when the amount of heat exchanged in the condenser or evaporator decreases due to a change in the outside air temperature.
  • a decrease in the amount of heat exchanged in the condenser can occur when a large amount of liquid refrigerant remains in the condenser and heat exchange with the gas refrigerant is hindered.
  • a decrease in the amount of heat exchanged in the evaporator can occur when the outside air temperature during heating operation is low, causing frost to form on the evaporator, or when the refrigerant flow rate is adjusted using an expansion valve, etc.
  • the discharge temperature of compressor 11 may become excessively low.
  • a value close to the saturation temperature of the highest boiling point component that constitutes the non-azeotropic refrigerant mixture can be incorporated as the allowable lower limit of the discharge temperature of compressor 11.
  • the current discharge temperature To of the mixed refrigerant is obtained (step S111).
  • the state of the equipment to be controlled such as the opening degree of the indoor expansion valve 33 and the outdoor expansion valve 15, the rotation speed of the compressor 11, and the rotation speed of the outdoor blower 14, may be obtained and used to determine which state of the controlled object should be changed.
  • step S112 the current discharge temperature To of the mixed refrigerant is compared with a preset threshold value Th2 (step S112).
  • a value corresponding to the heat resistance allowable temperature of the compressor 11 can be set in advance.
  • the threshold value Th2 it is preferable to set a value of 120°C, which corresponds to a general heat resistance allowable temperature, or a value less than 120°C that ensures a margin with respect to the heat resistance allowable temperature.
  • step S112 If the comparison shows that the current discharge temperature To of the mixed refrigerant is less than the threshold value Th2 (step S112; NO), the discharge temperature of the compressor 11 is within the appropriate range, and the process proceeds to step S114.
  • step S112 if the comparison shows that the current discharge temperature To of the mixed refrigerant is equal to or higher than the threshold value Th2 (step S112; YES), the discharge temperature of the compressor 11 is high, so the process proceeds to step S113.
  • control is performed to decrease the discharge temperature of the compressor 11 (step S113).
  • the discharge temperature of the compressor 11 is prevented from becoming excessively high with respect to the heat resistance allowable temperature.
  • the opening degree of the indoor expansion valve 33 is increased during cooling operation, and the opening degree of the outdoor expansion valve 15 is increased during heating operation.
  • the drive frequency of the compressor 11 may be lowered to reduce the rotation speed, the rotation speed of the outdoor blower 14 may be increased during cooling operation, or the opening degree of the injection valve 21 may be increased.
  • the opening of the expansion valve When the opening of the expansion valve is increased, the refrigerant flow rate to the compressor 11 increases, and the pressure ratio between the discharge pressure and the suction pressure decreases, causing the discharge temperature of the compressor 11 to decrease.
  • the rotation speed of the compressor 11 When the rotation speed of the compressor 11 is decreased, the discharge pressure of the compressor decreases, causing the discharge temperature of the compressor 11 to decrease.
  • the rotation speed of the outdoor blower 14 When the rotation speed of the outdoor blower 14 is increased, the amount of heat exchanged in the outdoor heat exchanger 13 increases, causing the discharge temperature of the compressor 11 to decrease.
  • the opening of the injection valve 21 When the opening of the injection valve 21 is increased, the specific enthalpy of the refrigerant sucked into the compressor 11 is more likely to decrease, causing the discharge temperature of the compressor 11 to decrease.
  • step S10 while performing control to decrease the discharge temperature of the compressor 11, similarly to FIG. 4, the current discharge pressure Pd of the mixed refrigerant and the current discharge temperature To of the mixed refrigerant are obtained (step S10), the saturation temperature TsH of the highest boiling point component is calculated (step S11), and the current discharge temperature To of the mixed refrigerant is compared with the threshold value Th1 (step S12).
  • step S12 If the comparison result shows that the current discharge temperature To of the mixed refrigerant exceeds the threshold value Th1 corresponding to the vicinity of the saturation temperature TsH of the highest boiling point component (step S12; NO), the discharge temperature of the compressor 11 is within the appropriate range, so the process returns to step S10.
  • step S12 when the comparison result shows that the current discharge temperature To of the mixed refrigerant is equal to or lower than the threshold value Th1 corresponding to the vicinity of the saturation temperature TsH of the highest boiling point component (step S12; YES), the discharge temperature of the compressor 11 is low, so the process proceeds to step S13.
  • control is performed to increase the discharge temperature of the compressor 11 (step S13).
  • a decrease in the viscosity of the refrigeration oil is suppressed.
  • the opening of the indoor expansion valve 33 is reduced during cooling operation, and the opening of the outdoor expansion valve 15 is reduced during heating operation.
  • the drive frequency of the compressor 11 may be increased to increase the rotation speed, or the rotation speed of the outdoor blower 14 may be reduced during cooling operation.
  • the opening of the injection valve 21 may be reduced.
  • step S114 it is determined whether the stop condition for responding to excessive fluctuations in the compressor discharge temperature during equipment operation is met.
  • Stop conditions for dealing with excessive fluctuations in the compressor discharge temperature include conditions indicating that the compressor 11 should be stopped and conditions indicating that the discharge temperature of the compressor 11 will not become excessively high. For example, if the outdoor temperature is above a predetermined value and freezing or the like will not occur, or if the suction pressure of the compressor 11 is above a predetermined value, the discharge temperature of the compressor 11 is unlikely to become high, so a series of controls can be stopped. Also, if the compressor discharge temperature during operation remains within a range of plus or minus a few degrees of the target discharge temperature for a certain period of time, it is possible to determine that the transient increase or decrease in the discharge temperature has ended.
  • step S114 If the determination result is that the stop condition for dealing with excessive fluctuations in the compressor discharge temperature is not met (step S114; NO), the process returns to step S111.
  • step S114 if the determination result indicates that the stop condition for dealing with excessive fluctuations in the compressor discharge temperature is met (step S114; YES), the series of controls ends.
  • the control of the compressor discharge temperature based on the saturation temperature of the highest boiling point component may be incorporated as a lower level control executed after controlling the upper limit of the compressor discharge temperature, as shown in FIG. 6, or, unlike FIG. 6, may be incorporated as a higher level control executed before controlling the upper limit of the compressor discharge temperature.
  • control of the compressor discharge temperature based on the saturation temperature of the highest boiling point component may be performed continuously at all times, or may be performed intermittently at a specified time interval.
  • the compressor 11 can also be controlled so that the discharge superheat reaches a target value while the upper limit of the discharge temperature is protected by a series of controls.
  • the discharge superheat degree refers to the degree of superheat of the refrigerant on the discharge side of the compressor.
  • the discharge superheat degree represents the difference between the discharge temperature of the refrigerant at a certain discharge pressure and the saturation temperature of the refrigerant at that discharge pressure.
  • the discharge temperature of the refrigerant can be measured by the discharge side temperature sensor 27 installed on the discharge side of the compressor 11.
  • the saturation temperature of the refrigerant can be obtained based on the relationship between the pressure and saturation temperature of the refrigerant.
  • the target value for the discharge superheat is set to an appropriate value depending on the type of refrigerant sealed in the refrigerant circuit.
  • Fig. 7 is a flow chart showing an example of application of the control of the compressor discharge temperature.
  • Fig. 7 shows an example in which the control of the compressor discharge temperature based on the saturation temperature of the highest boiling point component constituting the non-azeotropic refrigerant mixture is applied to the control of the discharge temperature during normal operation of the compressor 11. 7, in the air conditioner 1, the expansion valve and the compressor 11 can be controlled so that the discharge temperature during normal operation of the compressor 11 falls within a target range. In such control, a numerical value corresponding to the vicinity of the saturation temperature of the highest boiling point component constituting the non-azeotropic refrigerant mixture can be incorporated as the lower limit of the discharge temperature of the compressor 11.
  • the saturation temperature TsH of the highest boiling point component at the current discharge pressure Pd of the mixed refrigerant is calculated based on the current discharge pressure Pd (step S122).
  • the current discharge temperature To of the mixed refrigerant is compared with a preset threshold value Th3 (step S123).
  • the threshold value Th3 is set as the upper limit of the target value of the discharge temperature of the compressor 11.
  • step S123 If the comparison result indicates that the current discharge temperature To of the mixed refrigerant is equal to or higher than the threshold value Th3 (step S123; YES), the process proceeds to step S124.
  • step S124 to control the discharge temperature of the mixed refrigerant, one or more of the following is performed (step S124): increasing the opening of the expansion valve, and decreasing the drive frequency of the compressor 11 to decrease the rotational speed (step S124).
  • increasing the opening of the expansion valve increases the refrigerant flow rate to the compressor 11, and the pressure ratio between the discharge pressure and the suction pressure decreases, decreasing the discharge temperature of the mixed refrigerant.
  • Reducing the rotational speed of the compressor 11 reduces the compressor discharge pressure and decreases the discharge temperature of the mixed refrigerant.
  • step S123 if the comparison shows that the current discharge temperature To of the mixed refrigerant is less than the threshold value Th3 (step S123; NO), the process proceeds to step S125.
  • the current discharge temperature To of the mixed refrigerant is compared with a threshold value Th4 set based on the saturation temperature TsH of the highest boiling point component (step S125).
  • the threshold value Th4 is a value indicating a lower temperature than the threshold value Th3, and is set as the lower limit of the target value of the discharge temperature of the compressor 11.
  • the threshold value Th4 is set to a value close to the saturation temperature TsH of the highest boiling point component constituting the non-azeotropic refrigerant mixture. It is preferable to set the threshold value Th4 to a value that is -10°C below the saturation temperature TsH of the highest boiling point component for each arbitrary current pressure.
  • step S125 If the comparison shows that the current discharge temperature To of the mixed refrigerant is equal to or lower than the threshold value Th4 (step S125; YES), the process proceeds to step S126.
  • step S126 to increase the discharge temperature of the mixed refrigerant, one or more of the following controls are performed (step S126): reducing the opening of the expansion valve, and increasing the drive frequency of the compressor 11 to increase the rotational speed.
  • the opening of the expansion valve is reduced, the refrigerant flow rate to the compressor 11 decreases, and the pressure ratio between the discharge pressure and the suction pressure increases, causing the discharge temperature of the mixed refrigerant to rise.
  • the rotational speed of the compressor 11 is increased, the discharge pressure of the compressor increases, causing the discharge temperature of the mixed refrigerant to rise.
  • step S125 if the comparison shows that the current discharge temperature To of the mixed refrigerant exceeds the threshold value Th4 (step S125; NO), the process proceeds to step S127.
  • step S127 it is determined whether the stop condition for controlling the discharge temperature of the compressor 11 is met.
  • Stop conditions for controlling the discharge temperature of the compressor 11 include conditions indicating that the compressor 11 is stopped and conditions indicating that the discharge temperature of the compressor 11 does not fluctuate excessively.
  • step S127 If the determination result indicates that the stop condition for controlling the discharge temperature of the compressor 11 is not met (step S127; NO), the process returns to step S121.
  • step S127 if the determination result indicates that the stop condition for controlling the discharge temperature of the compressor 11 is met (step S127; YES), the control of the current discharge temperature To is terminated.
  • the discharge temperature can be controlled toward a predetermined target value by controlling the expansion valve and the compressor 11.
  • the discharge temperature can be controlled so that it does not exceed the heat resistance allowable temperature of the compressor 11, and the dryness of the mixed refrigerant on the suction side of the compressor 11 is in a range that does not cause liquid return to the compressor 11.
  • the lower limit of the target value of the discharge temperature is limited based on the saturation temperature of the highest boiling point component that constitutes the non-azeotropic mixed refrigerant, so the discharge temperature does not become excessively low and is kept higher than before.
  • Refrigerant components including high boiling point components, are less likely to exist in a liquid state, so they are less likely to dissolve in the refrigeration oil sealed in the compressor, and poor lubrication of the compressor is suppressed. This ensures the soundness of the compressor and improves the product reliability of the air conditioner.
  • the control of the compressor discharge temperature based on the saturation temperature of the highest boiling point component that constitutes the non-azeotropic refrigerant mixture is applied to the control of the discharge temperature during normal operation of the compressor 11.
  • it can also be applied to control of the discharge superheat degree, control of the suction superheat degree, control of the suction dryness degree, and control of the superheat degree in the indoor heat exchanger 31.
  • these lower limit values are set based on the saturation temperature of the highest boiling point component obtained on the discharge side of the compressor 11.
  • the superheat degree in the indoor heat exchanger 31 can be obtained as the difference between the outlet temperature and the inlet temperature in the indoor heat exchanger 31.
  • Fig. 8 is a flow chart showing an example of application of the control of the compressor discharge temperature.
  • Fig. 8 shows an example in which the control of the compressor discharge temperature based on the saturation temperature of the highest boiling point component constituting the non-azeotropic refrigerant mixture is applied to the control of the discharge temperature during the cooling cycle of the compressor 11.
  • the outdoor blower 14 can be controlled so that the discharge temperature of the compressor 11 is within a predetermined target range.
  • a value corresponding to the vicinity of the saturation temperature of the highest boiling point component constituting the non-azeotropic refrigerant mixture can be incorporated as the lower limit of the discharge temperature of the compressor 11.
  • the outdoor air temperature Tout outside the room where the outdoor unit 10 is located is acquired (step S131).
  • the outdoor air temperature Tout can be measured by installing a temperature sensor (not shown) in the outdoor unit 10.
  • controllability may be good if the rotation speed of the outdoor blower 14 is in an intermediate state so that it can be adjusted in both directions.
  • the outdoor air temperature Tout is compared with a preset threshold value Th5 (step S132).
  • the threshold value Th5 is set as the allowable lower limit of the operating temperature range of the outdoor heat exchanger 13 and the outdoor blower 14. For example, during cooling operation, if the outdoor air temperature Tout is extremely low, the amount of heat exchanged may be secured due to the temperature difference, and the discharge temperature of the compressor 11 is unlikely to increase, so the operating temperature range of the outdoor heat exchanger 13 and the outdoor blower 14 during discharge temperature control is limited.
  • step S132 If the comparison shows that the outside air temperature Tout is equal to or higher than the threshold value Th5 (step S132; YES), the current discharge temperature To of the compressor 11 can be controlled by the outdoor blower 14, and the process proceeds to step S133.
  • step S132 if the comparison shows that the outside air temperature Tout is less than the threshold value Th5 (step S132; NO), the outdoor blower 14 cannot control the current discharge temperature To of the compressor 11, so the process proceeds to step S139.
  • step S133 the current discharge pressure Pd of the mixed refrigerant and the current discharge temperature To of the mixed refrigerant are obtained.
  • the saturation temperature TsH of the highest boiling point component at the current discharge pressure Pd of the mixed refrigerant is calculated based on the current discharge pressure Pd (step S134).
  • the current discharge temperature To of the mixed refrigerant is compared with a preset threshold value Th6 (step S135).
  • the threshold value Th6 is set as the upper limit of the target value of the discharge temperature of the compressor 11.
  • step S135 If the comparison shows that the current discharge temperature To of the mixed refrigerant is equal to or higher than the threshold value Th6 (step S135; YES), the process proceeds to step S136.
  • the rotation speed of the outdoor blower 14 is increased to lower the discharge temperature of the mixed refrigerant (step S136).
  • the rotation speed of the outdoor blower 14 is increased, the amount of heat exchanged in the outdoor heat exchanger 13 increases, and the discharge pressure of the mixed refrigerant decreases. This may result in a decrease in the discharge temperature, but if the discharge temperature does not decrease to the target discharge temperature, it is desirable to control the opening of the expansion valve to be increased, and control the discharge temperature to close to the target discharge temperature.
  • step S135 if the comparison shows that the current discharge temperature To of the mixed refrigerant is less than the threshold value Th6 (step S135; NO), the process proceeds to step S137.
  • the current discharge temperature To of the mixed refrigerant is compared with a threshold value Th7 set based on the saturation temperature TsH of the highest boiling point component (step S137).
  • the threshold value Th7 is a value indicating a lower temperature than the threshold value Th6, and is set as the lower limit of the target value of the discharge temperature of the compressor 11.
  • the threshold value Th7 is set to a value close to the saturation temperature TsH of the highest boiling point component constituting the non-azeotropic refrigerant mixture. It is preferable to set the threshold value Th7 to a value that is -10°C below the saturation temperature TsH of the highest boiling point component for each arbitrary current pressure.
  • step S137 If the comparison shows that the current discharge temperature To of the mixed refrigerant is equal to or lower than the threshold value Th7 (step S137; YES), the process proceeds to step S138.
  • control is performed to reduce the rotation speed of the outdoor blower 14 (step S138).
  • the rotation speed of the outdoor blower 14 is reduced, the amount of heat exchanged in the outdoor heat exchanger 13 decreases and the discharge pressure of the compressor 11 increases. This may cause the discharge temperature to increase, but if the discharge temperature does not rise to the target discharge temperature, it is desirable to control the opening of the expansion valve to be reduced and control it to close to the target discharge temperature.
  • step S137 if the comparison shows that the current discharge temperature To of the mixed refrigerant exceeds the threshold value Th7 (step S137; NO), the process proceeds to step S139.
  • step S139 it is determined whether the stop condition for controlling the discharge temperature of the compressor 11 is met.
  • Stop conditions for controlling the discharge temperature of the compressor 11 include conditions indicating that the compressor 11 is stopped and conditions indicating that the discharge temperature of the compressor 11 does not fluctuate excessively.
  • step S139 If the determination result indicates that the stop condition for controlling the discharge temperature of the compressor 11 is not met (step S139; NO), the process returns to step S131.
  • step S139 if the determination result indicates that the stop condition for controlling the discharge temperature of the compressor 11 is met (step S139; YES), the control of the current discharge temperature To is terminated.
  • the discharge temperature can be controlled toward a predetermined target value by controlling the outdoor blower 14.
  • the discharge temperature can be controlled so that it does not exceed the heat resistance allowable temperature of the compressor 11, and the dryness of the mixed refrigerant on the suction side of the compressor 11 is in a range that does not cause liquid return to the compressor 11.
  • the lower limit of the target value of the discharge temperature is limited based on the saturation temperature of the highest boiling point component that constitutes the non-azeotropic mixed refrigerant, so the discharge temperature does not become excessively low and is kept higher than before.
  • Refrigerant components including high boiling point components, are less likely to exist in a liquid state, so they are less likely to dissolve in the refrigeration oil sealed in the compressor, and poor lubrication of the compressor is suppressed. This ensures the soundness of the compressor and improves the product reliability of the air conditioner.
  • the control of the compressor discharge temperature based on the saturation temperature of the highest boiling point component that constitutes the non-azeotropic refrigerant mixture is applied to the control of the discharge temperature during the cooling cycle of compressor 11.
  • it can also be applied to control of the discharge superheat degree, control of the suction superheat degree, control of the suction dryness degree, and control of the superheat degree in the indoor heat exchanger 31.
  • these lower limit values are set based on the saturation temperature of the highest boiling point component obtained on the discharge side of compressor 11.
  • the superheat degree in the indoor heat exchanger 31 can be obtained as the difference between the outlet temperature and the inlet temperature in the indoor heat exchanger 31.
  • the outdoor air temperature Tout is compared with a preset threshold value Th5, but instead of the outdoor air temperature Tout, the heat exchange temperature in the middle part of the outdoor heat exchanger 13 may be compared. Furthermore, when controlling based on the saturation temperature of the highest boiling point component, such a comparison may be omitted.
  • Fig. 9 is a flow chart showing an example of application of the control of the compressor discharge temperature.
  • Fig. 9 shows an example in which the control of the compressor discharge temperature based on the saturation temperature of the highest boiling point component constituting the non-azeotropic refrigerant mixture is applied to the control of the discharge temperature of the compressor 11.
  • the injection valve 21 can be controlled so that the discharge temperature of the compressor 11 does not exceed a predetermined upper limit.
  • a value close to the saturation temperature of the highest boiling point component constituting the non-azeotropic refrigerant mixture can be incorporated as the lower limit of the discharge temperature of the compressor 11.
  • the outdoor air temperature Tout outside the room where the outdoor unit 10 is located is acquired (step S141).
  • the outdoor air temperature Tout can be measured by installing a temperature sensor (not shown) in the outdoor unit 10.
  • the injection valve 21 is fully closed.
  • the outdoor air temperature Tout is compared with a preset threshold value Th8 (step S142).
  • the threshold value Th8 is set as the allowable lower limit of the operating temperature range of the outdoor heat exchanger 13. For example, during heating operation, if the outdoor air temperature Tout is extremely low, the amount of heat exchange cannot be secured, and the operating temperature range of the outdoor heat exchanger 13 is limited.
  • step S142 If the comparison result indicates that the outside air temperature Tout is equal to or higher than the threshold value Th8 (step S142; YES), the injection to the suction side of the compressor 11 is enabled, and the process proceeds to step S143.
  • step S142 if the comparison shows that the outside air temperature Tout is less than the threshold value Th8 (step S142; NO), injection to the suction side of the compressor 11 is not necessary, so the process proceeds to step S149.
  • the saturation temperature TsH of the highest boiling point component at the current discharge pressure Pd of the mixed refrigerant is calculated based on the current discharge pressure Pd (step S144).
  • the current discharge temperature To of the mixed refrigerant is compared with a preset threshold value Th9 (step S145).
  • the threshold value Th9 is set as the allowable upper limit value of the current discharge temperature To.
  • step S145 If the comparison shows that the current discharge temperature To of the mixed refrigerant is equal to or higher than the threshold value Th9 (step S145; YES), the process proceeds to step S146.
  • the opening of the injection valve 21 is increased to lower the discharge temperature of the mixed refrigerant (step S146).
  • the opening of the injection valve 21 is increased, the specific enthalpy of the refrigerant sucked into the compressor 11 tends to decrease, and the discharge temperature of the compressor 11 decreases.
  • the opening of the injection valve 21 and the opening of the outdoor expansion valve 15 can be synchronously controlled to adjust the distribution ratio of the mixed refrigerant.
  • step S145 if the comparison shows that the current discharge temperature To of the mixed refrigerant is less than the threshold value Th9 (step S145; NO), the process proceeds to step S147.
  • the current discharge temperature To of the mixed refrigerant is compared with a threshold value Th10 set based on the saturation temperature TsH of the highest boiling point component (step S147).
  • the threshold value Th10 is a value indicating a lower temperature than the threshold value Th9, and is set as the allowable lower limit value of the current discharge temperature To.
  • the threshold value Th10 is set to a value close to the saturation temperature TsH of the highest boiling point component constituting the non-azeotropic refrigerant mixture. It is preferable to set the threshold value Th10 to a value that is -10°C below the saturation temperature TsH of the highest boiling point component for each arbitrary current pressure.
  • step S147 If the comparison shows that the current discharge temperature To of the mixed refrigerant is equal to or lower than the threshold value Th10 (step S147; YES), the process proceeds to step S148.
  • the opening of the injection valve 21 is reduced to increase the discharge temperature of the mixed refrigerant (step S148).
  • the specific enthalpy of the refrigerant sucked into the compressor 11 becomes less likely to decrease, and the discharge temperature of the compressor 11 increases.
  • step S147 if the comparison shows that the current discharge temperature To of the mixed refrigerant exceeds the threshold value Th10 (step S147; NO), the process proceeds to step S149.
  • step S149 it is determined whether the stop condition for controlling the discharge temperature of the compressor 11 is met.
  • Stop conditions for controlling the discharge temperature of the compressor 11 include conditions indicating that the compressor 11 is stopped and conditions indicating that the discharge temperature of the compressor 11 does not fluctuate excessively.
  • step S149 If the determination result indicates that the stop condition for controlling the discharge temperature of the compressor 11 is not met (step S149; NO), the process returns to step S141.
  • step S149 if the determination result indicates that the stop condition for controlling the discharge temperature of the compressor 11 is met (step S149; YES), the control of the current discharge temperature To is terminated.
  • the injection valve 21 can be controlled so that the discharge temperature does not exceed a predetermined upper limit.
  • the discharge temperature can be suppressed while ensuring the refrigerant flow rate by injection that bypasses the evaporator.
  • the allowable lower limit of the discharge temperature is limited based on the saturation temperature of the highest boiling point component that constitutes the non-azeotropic refrigerant mixture, so the discharge temperature does not become excessively low and is kept higher than before.
  • Refrigerant components, including high boiling point components are less likely to exist in a liquid state, making them less likely to dissolve in the refrigeration oil sealed in the compressor, suppressing poor lubrication of the compressor. This ensures the soundness of the compressor and improves the product reliability of the air conditioner.
  • the control of the compressor discharge temperature based on the saturation temperature of the highest boiling point component that constitutes the non-azeotropic refrigerant mixture is applied to the control of the discharge temperature during heating operation of the compressor 11.
  • it can also be applied to control of the discharge superheat degree, control of the discharge superheat degree SH, control of the suction superheat degree, control of the suction dryness degree, and control of the superheat degree in the indoor heat exchanger 31.
  • these lower limit values are set based on the saturation temperature of the highest boiling point component obtained on the discharge side of the compressor 11.
  • the superheat degree in the indoor heat exchanger 31 can be obtained as the difference between the outlet temperature and the inlet temperature of the indoor heat exchanger 31.
  • the outdoor air temperature Tout is compared with a preset threshold value Th8, but instead of the outdoor air temperature Tout, the heat exchange temperature in the middle part of the outdoor heat exchanger 13 may be compared. Furthermore, when controlling based on the saturation temperature of the highest boiling point component, such a comparison may be omitted.
  • Non-azeotropic refrigerants are composed of two or more refrigerant components.
  • a non-azeotropic refrigerant is a refrigerant that exhibits the properties of a mixture over the entire composition range of two or more refrigerant components, and refers to a mixed refrigerant in which each refrigerant component has a different boiling point.
  • a non-azeotropic refrigerant is composed of two or more refrigerant components, it can contain any number of refrigerant components greater than two.
  • the global warming potential (GWP) of a non-azeotropic refrigerant mixture is preferably 750 or less, more preferably 500 or less, even more preferably 150 or less, and even more preferably 100 or less.
  • a GWP of 750 or less results in a refrigerant with excellent environmental performance, and an air conditioner that is highly compliant with legal regulations can be obtained.
  • the GWP of a non-azeotropic refrigerant mixture can be adjusted by changing the composition ratio of the refrigerant components.
  • the value (100-year value) from the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) is used as the GWP.
  • IPCC Intergovernmental Panel on Climate Change
  • AR4 the value from the IPCC Fifth Assessment Report (AR5) may be used, or a value listed in other publicly known documents may be used, or a value calculated or measured using a publicly known method may be used.
  • the non-azeotropic refrigerant mixture preferably contains 2,3,3,3-tetrafluoropropene (R1234yf, HFO1234yf), trans-1,3,3,3-tetrafluoropropene (R1234ze(E), HFO1234ze(E)), or trifluoroiodomethane (R13I1) as the relatively high boiling point component or highest boiling point component.
  • the boiling point of R1234yf is -29.5°C.
  • the boiling point of R1234ze(E) is -19.0°C.
  • the boiling point of R13I1 is -21.9°C.
  • the amount of high boiling point components mixed depends on the required refrigerant properties of the non-azeotropic refrigerant mixture, but is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more per 100% by mass of the non-azeotropic refrigerant mixture. It is also preferably less than 90% by mass, more preferably less than 70% by mass, and even more preferably less than 50% by mass.
  • the non-azeotropic refrigerant mixture preferably contains one or more of the following low-boiling components with relatively low boiling points: difluoromethane (R32, HFC32), trans-1,2-difluoroethylene (R1132(E), HFO1132(E)), 1,1-difluoroethylene (R1132a, HFO1132a), and trifluoroethylene (R1123, HFO1123).
  • difluoromethane R32, HFC32
  • trans-1,2-difluoroethylene R1132(E), HFO1132(E)
  • 1,1-difluoroethylene R1132a, HFO1132a
  • trifluoroethylene R1123, HFO1123
  • the boiling point of R32 is -51.7°C.
  • the boiling point of R1132(E) is -52.5°C.
  • the boiling point of R1132a is -86.7°C.
  • the boiling point of R1123 is -59.1°C.
  • the standard boiling point is low like the conventional R410A, and the operating pressure is easily secured, so the required refrigerant performance can be achieved with a low GWP. It is also possible to reduce the amount of refrigerant charged, improve energy efficiency, and improve safety through low toxicity.
  • the amount of low boiling point components mixed depends on the required refrigerant properties of the non-azeotropic refrigerant mixture, but is preferably 10% by mass or more, more preferably 30% by mass or more, and even more preferably 50% by mass or more per 100% by mass of the non-azeotropic refrigerant mixture. It is also preferably less than 90% by mass, more preferably less than 80% by mass, and even more preferably less than 70% by mass.
  • the amount of R32 mixed may be less than 50% by mass or less than 30% by mass.
  • the vapor pressure of the non-azeotropic refrigerant mixture at 25°C is preferably 1.4 MPa or more and 2.1 MPa or less. With such a vapor pressure, conventional air conditioners that use R32, R410A, etc. can be converted to a configuration that uses a non-azeotropic refrigerant mixture without making major design changes.
  • the vapor pressure of the non-azeotropic refrigerant mixture can be adjusted by changing the composition ratio of the refrigerant components.
  • the high boiling point component or the highest boiling point component that constitutes the non-azeotropic refrigerant mixture preferably has a vapor pressure of 0.3 MPa or more and 0.9 MPa or less at 25°C. Such a vapor pressure ensures appropriate refrigerant characteristics due to the high boiling point component and operating pressure due to the low boiling point component. In addition, the full effect of controlling the compressor discharge temperature based on the saturation temperature of the highest boiling point component that constitutes the non-azeotropic refrigerant mixture can be obtained.
  • the non-azeotropic refrigerant mixture may contain CO2 , hydrocarbons, ethers, fluoroethers, fluoroalkenes, HFCs, HFOs, HClFOs, HClFOs, HBrFOs, and the like as other refrigerant components.
  • HFC stands for hydrofluorocarbon.
  • HFO is a hydrofluoroolefin consisting of carbon, fluorine and hydrogen atoms and has at least one carbon-carbon double bond.
  • HClFO is consisting of carbon, chlorine, fluorine and hydrogen atoms and has at least one carbon-carbon double bond.
  • HBrFO is consisting of carbon, bromine, fluorine and hydrogen atoms and has at least one carbon-carbon double bond.
  • HFCs include pentafluoroethane (HFC125), 1,1,2,2-tetrafluoroethane (HFC134), 1,1,1,2-tetrafluoroethane (HFC134a), trifluoroethane (HFC143a), difluoroethane (HFC152a), 1,1,1,2,3,3,3-heptafluoropropane (HFC227ea), 1,1,1,3,3,3-hexafluoropropane (HFC236fa), 1,1,1,3,3-pentafluoropropane (HFC245fa), and 1,1,1,3,3-pentafluorobutane (HFC365mfc).
  • fluoroalkenes examples include fluoroethene, fluoropropene, fluorobutene, chlorofluoroethene, chlorofluoropropene, and chlorofluorobutene.
  • fluoropropenes examples include 3,3,3-trifluoropropene (HFO1243zf) and HFO1225.
  • fluorobutenes include C 4 H 4 F 4 , C 4 H 3 F 5 (HFO1345), and C 4 H 2 F 6 (HFO1336).
  • chlorofluoroethene is C 2 F 3 Cl (CTFE).
  • chlorofluoropropene is 2-chloro-3,3,3-trifluoro-1-propene (HCFO1233xf) or 1-chloro-3,3,3-trifluoro-1-propene (HCFO1233zd).
  • non-azeotropic mixed refrigerants include R407C, R407E, R407H, R407I, R447A, R449C, R452B, R454A, R454B, R454C, R466A, etc., mixed refrigerants with adjusted composition ratios, and mixed refrigerants in which other refrigerant components are mixed with these.
  • Other examples include refrigerants made non-azeotropic by mixing other refrigerant components with R32 or R410A.
  • Non-azeotropic refrigerant mixtures can contain additives such as stabilizers that suppress decomposition of the refrigerant components, and polymerization inhibitors that suppress polymerization of the refrigerant components, in addition to two or more refrigerant components.
  • stabilizers include epoxy compounds, nitro compounds, amine compounds, benzotriazole compounds, and pinene compounds.
  • polymerization inhibitors include thioether compounds, amine compounds, nitroso compounds, hydroxy aromatic compounds, and quinone compounds.
  • the non-azeotropic refrigerant mixture preferably has a flame retardant parameter of 0.46 or less, as shown in the following formula (I):
  • F is the flame retardant parameter of the refrigerant mixture
  • Fi is the flame retardant parameter of each refrigerant component
  • xi is the molar fraction of each refrigerant component.
  • Fmix ⁇ iFi ⁇ xi ... (I)
  • the refrigeration oil polyol ester oil, polyvinyl ether oil, polyalkylene glycol oil, etc. can be used.
  • the refrigeration oil is sealed in an oil reservoir provided inside the compressor 11. The refrigeration oil is sucked from the oil reservoir while the compressor 11 is operating, and is supplied to the sliding parts such as the scroll and bearings.
  • the refrigeration oil preferably has a kinetic viscosity of 30 mm 2 /s or more and 100 mm 2 /s or less at 40° C.
  • the kinetic viscosity is measured based on standards such as ISO (International Organization for Standardization) 3104 and ASTM (American Society for Testing and Materials) D445 and D7042. With such a kinetic viscosity, it is possible to appropriately ensure the lubricity of the sliding parts of the compressor and the airtightness of the compression chamber.
  • the low-temperature critical solution temperature of the refrigeration oil and the non-azeotropic refrigerant mixture is preferably +10°C or lower, and more preferably 0°C or lower.
  • Such a low-temperature critical solution temperature can suppress two-phase separation between the refrigeration oil and the non-azeotropic refrigerant mixture at low temperatures. This ensures the return of oil to the compressor 11.
  • Refrigeration oils can contain base oils such as polyol ester oil, polyvinyl ether oil, polyalkylene glycol oil, and additives such as acid scavengers, antioxidants, extreme pressure agents, stabilizers, defoamers, and metal deactivators.
  • base oils such as polyol ester oil, polyvinyl ether oil, polyalkylene glycol oil, and additives such as acid scavengers, antioxidants, extreme pressure agents, stabilizers, defoamers, and metal deactivators.
  • additives such as acid scavengers, antioxidants, extreme pressure agents, stabilizers, defoamers, and metal deactivators.
  • additives such as acid scavengers, antioxidants, extreme pressure agents, stabilizers, defoamers, and metal deactivators.
  • POE extreme pressure agents
  • polyol ester oils or polyvinyl ether oils are preferred compared to polyalkylene glycol oils, and polyol ester oils represented by the following chemical formula (1) or (2) or polyvinyl ether oils represented by the following chemical formula (3) are more preferred.
  • Polyalkylene glycol oils have a lower volume resistivity than polyvinyl ether oils or polyol ester oils in terms of electrical insulation of the hermetic compressor in which the compressor motor is built. For this reason, polyvinyl ether oils or polyol ester oils are more desirable in air conditioners in which HFC refrigerants or HFO refrigerants are sealed.
  • R1 to R10 represent alkyl groups having 4 to 9 carbon atoms and may be the same or different.
  • OR11 represents a methyloxy group, an ethyloxy group, a propyloxy group, or a butyloxy group.
  • n represents an integer from 5 to 15.
  • the alkyl group may be either a straight-chain alkyl group or a branched alkyl group.
  • alkyl groups include n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, 3-pentyl, tert-pentyl, neopentyl, 1-ethylpentyl, isohexyl, and 2-ethylhexyl.
  • Refrigeration oils represented by chemical formulas (1) to (3) provide suitable compatibility and good lubricity depending on the non-azeotropic refrigerant mixture.
  • Polyol ester oils represented by chemical formulas (1) or (2) provide high thermal stability, oxidation stability, low-temperature flow properties, and a high viscosity index in addition to good lubricity.
  • chemical formula (1) or chemical formula (2) may be used, or a mixture of these may be used.
  • the compressor discharge temperature is controlled based on the saturation temperature of the highest boiling point component that constitutes the non-azeotropic refrigerant mixture, thereby suppressing the dissolution of the highest boiling point component and other refrigerant components into the refrigeration oil.
  • refrigeration oils represented by chemical formulas (1) to (3) are used, the adverse effects of the high boiling point components are relatively suppressed, and a more appropriate viscosity can be maintained. This results in more appropriate compatibility, better lubricity, etc.
  • the present invention is not limited to the above-described embodiments, and various modifications are included as long as they do not deviate from the technical scope.
  • the above-described embodiments are not necessarily limited to those having all of the configurations described. It is also possible to replace part of the configuration of an embodiment with another configuration, or to add another configuration to the configuration of an embodiment. It is also possible to add other configurations to, delete configurations, or replace configurations with respect to part of the configuration of an embodiment.
  • the air conditioner 1 can be used to configure any suitable air conditioner, such as a room air conditioner, a packaged air conditioner, or a multi-air conditioner for buildings.
  • any suitable air conditioner such as a room air conditioner, a packaged air conditioner, or a multi-air conditioner for buildings.
  • the air conditioner has multiple compressors, it is preferable to control the discharge temperature of at least one compressor, and it is even more preferable to control the discharge temperatures of all compressors, based on the saturation temperature of the highest boiling point component that constitutes the non-azeotropic refrigerant mixture.
  • the air conditioner 1 may also be equipped with sensors (not shown) and devices that make up the refrigerant circuit, such as a temperature sensor that measures the temperature of the two-phase refrigerant in the middle of the heat exchanger, a temperature sensor that measures the temperature of the refrigerant on the outlet side of the heat exchanger, a receiver, an oil separator, a dryer, etc.
  • sensors not shown
  • devices that make up the refrigerant circuit, such as a temperature sensor that measures the temperature of the two-phase refrigerant in the middle of the heat exchanger, a temperature sensor that measures the temperature of the refrigerant on the outlet side of the heat exchanger, a receiver, an oil separator, a dryer, etc.
  • the air conditioner 1 is also equipped with an injection pipe 19 and an injection valve 21, but these can be omitted if injection into the compressor 11 is not performed.
  • the suction side pressure sensor 24, suction side temperature sensor 25, discharge side pressure sensor 26, and discharge side temperature sensor 27 can also be omitted if measurements are not performed.
  • the saturation temperature of the highest boiling point component at the discharge pressure of the compressor 11 is determined based on actual measurement on the discharge side of the compressor 11, but it can also be determined by estimation based on the suction temperature and enthalpy change in the compressor 11 and the condensation temperature in the condenser.
  • the stop conditions are set independently for the control of the compressor discharge temperature based on the saturation temperature of the highest boiling point component that constitutes the non-azeotropic refrigerant mixture, but it may be operated synchronously with the control of the operation of the air conditioner 1 or the control of the operation of the equipment.
  • the control of the compressor discharge temperature may be performed continuously at all times, or may be performed intermittently at a specified time interval.
  • the air conditioner 1 may also be an air conditioner equipped with a refrigerant circuit in which a compressor, a condenser, a pressure reducer, and an evaporator are connected in this order by refrigerant piping to circulate a refrigerant, the refrigerant being a non-azeotropic refrigerant mixture composed of two or more refrigerant components, the non-azeotropic refrigerant mixture containing one or more of R1234yf, R1234ze(E) and R13I1 as high boiling point components, and containing one or more of R32, R1132(E), R1132a and R1123 as low boiling point components having boiling points lower than those of the high boiling point components, and the discharge temperature of the compressor may be controlled to a temperature higher than the saturation temperature at the discharge pressure of the compressor of the highest boiling point component, which has the highest boiling point among the refrigerant components.
  • the air conditioner 1 may also be an air conditioner equipped with a refrigerant circuit in which a compressor, a condenser, a pressure reducer, and an evaporator are connected in that order by refrigerant piping, and equipped with an outdoor heat exchanger that functions as the condenser during cooling operation and as the evaporator during heating operation, and an outdoor blower that blows outside air to the outdoor heat exchanger, the refrigerant being a non-azeotropic refrigerant mixture composed of two or more refrigerant components, and the discharge temperature of the compressor may be controlled to a temperature higher than the saturation temperature of the highest boiling point component at the discharge pressure of the compressor by any one or more of the opening degree of the pressure reducer, the rotation speed of the compressor, and the rotation speed of the outdoor blower.
  • the air conditioner 1 may also be an air conditioner equipped with a refrigerant circuit in which a compressor, a condenser, a pressure reducer, and an evaporator are connected in this order by refrigerant piping, and equipped with an injection pipe that connects the condenser to the compressor, bypassing the evaporator, and an injection valve that can open and close the injection pipe, the refrigerant is a non-azeotropic refrigerant mixture composed of two or more refrigerant components, and the discharge temperature of the compressor may be controlled to a temperature higher than the saturation temperature of the highest boiling point component at the discharge pressure of the compressor by any one or more of the opening degree of the pressure reducer, the rotation speed of the compressor, and the opening degree of the injection valve.
  • Air conditioner 2 Gas connection pipe 3 Liquid connection pipe 10 Outdoor unit 11 Compressor 12 Four-way valve 13 Outdoor heat exchanger (condenser/evaporator) 14 Outdoor blower 15 Outdoor expansion valve (pressure reducer) 16 Gas refrigerant piping 17 Compressor suction piping 18 Compressor discharge piping 19 Injection piping 20 Accumulator 21 Injection valve 24 Suction side pressure sensor 25 Suction side temperature sensor 26 Discharge side pressure sensor 27 Discharge side temperature sensor 30 Indoor unit 31 Indoor heat exchanger (evaporator/condenser) 32 Indoor blower 33 Indoor expansion valve (pressure reducer)

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

Abstract

La présente invention concerne un climatiseur dans lequel une défaillance de lubrification du compresseur est supprimée de manière appropriée dans un circuit de fluide frigorigène à l'aide d'un mélange de fluide frigorigène non azéotrope. Le climatiseur est un climatiseur (1) comprenant un circuit de fluide frigorigène dans lequel un compresseur (11), des condenseurs (13, 31), des réducteurs de pression (15, 33) et des évaporateurs (31, 13) sont reliés en séquence par des tuyaux de fluide frigorigène pour faire circuler un fluide frigorigène, le fluide frigorigène étant un mélange de fluide frigorigène non azéotrope d'au moins deux types de composants de fluide frigorigène, et la température de décharge du compresseur (11) étant commandée pour être supérieure à une température proche de la température de saturation à la pression de décharge de compresseur du composant de point d'ébullition le plus élevé présentant le point d'ébullition le plus élevé parmi les composants de fluide frigorigène.
PCT/JP2022/036586 2022-09-29 2022-09-29 Climatiseur WO2024069896A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002122364A (ja) * 2000-10-13 2002-04-26 Sanyo Electric Co Ltd 冷凍装置及びこの装置を用いた空気調和機
WO2016181529A1 (fr) * 2015-05-13 2016-11-17 三菱電機株式会社 Dispositif à cycle de réfrigération
WO2020039707A1 (fr) * 2018-08-22 2020-02-27 日立ジョンソンコントロールズ空調株式会社 Dispositif à cycle frigorifique et procédé de gestion de température de fluide frigorigène dans un dispositif à cycle frigorifique
WO2021176651A1 (fr) * 2020-03-05 2021-09-10 三菱電機株式会社 Échangeur de chaleur et climatiseur

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002122364A (ja) * 2000-10-13 2002-04-26 Sanyo Electric Co Ltd 冷凍装置及びこの装置を用いた空気調和機
WO2016181529A1 (fr) * 2015-05-13 2016-11-17 三菱電機株式会社 Dispositif à cycle de réfrigération
WO2020039707A1 (fr) * 2018-08-22 2020-02-27 日立ジョンソンコントロールズ空調株式会社 Dispositif à cycle frigorifique et procédé de gestion de température de fluide frigorigène dans un dispositif à cycle frigorifique
WO2021176651A1 (fr) * 2020-03-05 2021-09-10 三菱電機株式会社 Échangeur de chaleur et climatiseur

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