WO2024047832A1 - Refrigeration cycle device and air conditioning device - Google Patents

Refrigeration cycle device and air conditioning device Download PDF

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Publication number
WO2024047832A1
WO2024047832A1 PCT/JP2022/032912 JP2022032912W WO2024047832A1 WO 2024047832 A1 WO2024047832 A1 WO 2024047832A1 JP 2022032912 W JP2022032912 W JP 2022032912W WO 2024047832 A1 WO2024047832 A1 WO 2024047832A1
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Prior art keywords
refrigerant
temperature
heat exchanger
refrigeration cycle
dry protection
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PCT/JP2022/032912
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French (fr)
Japanese (ja)
Inventor
瑞朗 酒井
竜也 峯岡
佳浩 楊
Original Assignee
三菱電機株式会社
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Priority to PCT/JP2022/032912 priority Critical patent/WO2024047832A1/en
Publication of WO2024047832A1 publication Critical patent/WO2024047832A1/en

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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B1/00Compression machines, plants or systems with non-reversible cycle

Definitions

  • This technology relates to refrigeration cycle devices and air conditioners.
  • the present invention relates to dry protection control in a refrigerant circuit using a refrigerant having a temperature gradient.
  • a refrigeration cycle device such as an air conditioner circulates a refrigerant filled in a refrigerant circuit to exchange heat with a fluid such as air or water, thereby heating or cooling the fluid.
  • GWP global warming potential
  • Refrigerants with a high global warming potential cause global warming when released into the atmosphere.
  • refrigerants used in refrigeration cycle devices to shift to refrigerants with lower global warming coefficients due to increased environmental awareness. Therefore, in recent years, a non-azeotropic mixed refrigerant, which is a mixture of multiple types of refrigerants with different boiling points, has been used as a refrigerant with a low global warming potential.
  • control device that controls the equipment of the refrigeration cycle device corrects the evaporation temperature by using physical quantities such as the temperature detected by a detection device such as a sensor, and calculations from the physical quantities (for example, see Patent Document 1). .
  • dry protection control such as protection of the compressor or determination of insufficient amount of refrigerant is performed based on the dry state of the refrigerant.
  • a refrigerant circuit using a refrigerant having a temperature gradient, such as a non-azeotropic mixed refrigerant the temperature of the refrigerant differs during the evaporation process, so there is a possibility that appropriate correction may not be performed. For this reason, the overheating state of the refrigerant during the evaporation process cannot be accurately determined, and there is a possibility that dry protection control cannot be performed accurately.
  • a refrigeration cycle device has a refrigerant circuit configured by connecting a compressor, a condenser, an expansion valve, and an evaporator with piping, and circulates a mixed refrigerant having a temperature gradient.
  • a two-phase pipe temperature sensor detects the temperature of the mixed refrigerant passing through the heat exchanger, and the two-phase pipe temperature sensor corrects the heat exchanger passing temperature, and performs dry protection based on the corrected temperature. and a control device that performs dry protection control based on the determination.
  • the air conditioner according to this disclosure performs heating and cooling of a target space using the above-mentioned refrigeration cycle device.
  • the control device corrects the heat exchanger passing temperature detected by the two-phase pipe temperature sensor, and determines whether to perform dry protection control based on the corrected temperature. Then, dry protection control is performed based on the judgment. Therefore, it is possible to determine whether or not to perform dry protection control after correcting the heat exchanger passing temperature to a more accurate temperature. Therefore, the refrigeration cycle device can perform dry protection control based on a more accurate dry state.
  • FIG. 1 is a diagram showing the configuration of a refrigeration cycle device according to Embodiment 1.
  • FIG. 1 is a diagram showing a schematic configuration of an example of a heat exchanger according to Embodiment 1.
  • FIG. 3 is a diagram illustrating the configuration of a control device 400 in the air conditioner 1 according to the first embodiment. It is a pH diagram in a refrigeration cycle device.
  • FIG. 3 is a diagram showing the relationship between pressure and temperature in the evaporation process of a non-azeotropic mixed refrigerant when the pressure in the evaporator is constant in the refrigeration cycle device according to the first embodiment.
  • FIG. 3 is a diagram showing the relationship between pressure and temperature in the evaporation process of a non-azeotropic mixed refrigerant when a pressure difference occurs in the evaporator in the refrigeration cycle device according to the first embodiment.
  • FIG. 3 is a diagram showing a change in refrigerant temperature over time when the amount of refrigerant circulation is small in the outdoor heat exchanger 230 of the air conditioner 1 according to the first embodiment.
  • FIG. 6 is a diagram showing a temporal change in refrigerant temperature when the amount of refrigerant circulation is large in the outdoor heat exchanger 230 of the air conditioner 1 according to the first embodiment.
  • FIG. 7 is a diagram illustrating dry protection control processing of the refrigeration cycle device according to the second embodiment.
  • 3 is a diagram showing the configuration of a control device 400 according to Embodiment 3.
  • FIG. FIG. 4 is a diagram showing the configuration of a control device 400 according to a fourth embodiment.
  • FIG. 1 is a diagram showing the configuration of a refrigeration cycle device according to Embodiment 1.
  • the air conditioner 1 according to the first embodiment includes an outdoor unit 200, an indoor unit 100, and two refrigerant pipes 300.
  • the compressor 210, four-way valve 220, outdoor heat exchanger 230, and expansion valve 240 of the outdoor unit 200 are connected to the indoor heat exchanger 110 of the indoor unit 100 by a refrigerant pipe 300, and the refrigerant is circulated.
  • the indoor unit 100 may include the expansion valve 240.
  • the air conditioner 1 according to the first embodiment is configured such that one outdoor unit 200 and one indoor unit 100 are connected by piping. However, the number of connected devices is not limited to this.
  • the air conditioner 1 uses a non-azeotropic mixed refrigerant as the refrigerant that circulates within the refrigerant circuit.
  • a non-azeotropic mixed refrigerant is a refrigerant that is a mixture of multiple component refrigerants and whose composition changes when it evaporates and condenses.
  • a non-azeotropic mixed refrigerant is in a gas-liquid two-phase state under the same pressure and does not settle at a constant temperature as the composition changes. For example, in the evaporation process under the same pressure, the temperature of the non-azeotropic mixed refrigerant at the end of evaporation is higher than the refrigerant temperature at the start of evaporation.
  • the refrigerant temperature of the non-azeotropic mixed refrigerant at the end of condensation is lower than the refrigerant temperature at the start of condensation.
  • the temperature difference between the start and end of evaporation or condensation is the temperature gradient.
  • the non-azeotropic mixed refrigerant used in the air conditioner 1 in the first embodiment is R454B, which is a mixture of R32 refrigerant and R1234yf refrigerant, which are HFC (hydrofluorocarbon) refrigerants, at a ratio of 68.1:31.9. It shall be a refrigerant.
  • Outdoor unit 200 in Embodiment 1 includes a compressor 210, a four-way valve 220, and an outdoor heat exchanger 230 as devices constituting a refrigerant circuit. Furthermore, the outdoor unit 200 includes an outdoor blower 250 and a control device 400.
  • the compressor 210 compresses and discharges the sucked refrigerant.
  • Compressor 210 is, for example, a scroll compressor, a rotary compressor, a vane compressor, or the like.
  • the compressor 210 can change the circulating amount of refrigerant discharged by the compressor 210 by arbitrarily changing the driving frequency using, for example, an inverter circuit.
  • the four-way valve 220 serving as a flow path switching device is, for example, a valve that switches the flow of refrigerant between cooling operation and heating operation.
  • the four-way valve 220 connects the discharge side of the compressor 210 and the indoor heat exchanger 110 and connects the suction side of the compressor 210 and the outdoor heat exchanger 230 when heating operation is performed. Furthermore, the four-way valve 220 connects the discharge side of the compressor 210 to the outdoor heat exchanger 230 and connects the suction side of the compressor 210 to the indoor heat exchanger 110 when cooling operation is performed.
  • a flow path switching device may be formed by combining a plurality of two-way valves.
  • the outdoor heat exchanger 230 is a heat exchanger that exchanges heat between the refrigerant and outdoor air.
  • the outdoor heat exchanger 230 of Embodiment 1 functions as an evaporator during heating operation, absorbs heat from the refrigerant, evaporates it, and vaporizes the refrigerant into a gaseous refrigerant (hereinafter referred to as gas refrigerant).
  • gas refrigerant a gaseous refrigerant
  • it functions as a condenser, condenses the refrigerant, radiates heat, liquefies it as a liquid refrigerant (hereinafter referred to as liquid refrigerant), and passes it through.
  • the configuration of the outdoor heat exchanger 230 will be further explained later.
  • the outdoor blower 250 forms an air flow that causes air from outside the outdoor unit 200 to pass through the outdoor heat exchanger 230 and flow out from the outdoor unit 200, thereby facilitating heat exchange in the outdoor heat exchanger 230. prompt.
  • the expansion valve 240 which serves as a throttle device or the like, is a valve that reduces the pressure of the refrigerant and expands it.
  • the expansion valve 240 is, for example, an electronic expansion valve.
  • the expansion valve 240 adjusts its opening based on instructions from a control device 400 or the like, which will be described later, to reduce the pressure and control the amount of refrigerant passing through.
  • the indoor unit 100 performs indoor air conditioning.
  • the indoor unit 100 includes an indoor heat exchanger 110 as a device that constitutes a refrigerant circuit. Furthermore, the indoor unit 100 includes an indoor blower 120.
  • the indoor heat exchanger 110 is a heat exchanger that exchanges heat between indoor air, which is a space to be air-conditioned, and a refrigerant. For example, during heating operation, indoor heat exchanger 110 functions as a condenser, condenses refrigerant, and passes liquid refrigerant. Further, during cooling operation, the indoor heat exchanger 110 functions as an evaporator, evaporates the refrigerant, and passes the gas refrigerant.
  • the indoor blower 120 causes air to pass through the indoor heat exchanger 110 to promote heat exchange in the indoor heat exchanger 110, and supplies the air that has passed through the indoor heat exchanger 110 to the room that is the space to be air-conditioned.
  • each device in the air conditioner 1 will be explained based on the flow of refrigerant.
  • the operation of each device in the refrigerant circuit during heating operation will be explained based on the flow of refrigerant.
  • Solid line arrows in FIG. 1 indicate the flow of refrigerant during heating operation.
  • the high temperature and high pressure gas refrigerant compressed and discharged by the compressor 210 passes through the four-way valve 220 and flows into the indoor heat exchanger 110. While passing through the indoor heat exchanger 110, the gas refrigerant condenses and liquefies, for example, by exchanging heat with the air in the air-conditioned space.
  • the condensed and liquefied refrigerant passes through expansion valve 240 .
  • the refrigerant passes through the expansion valve 240, the pressure is reduced.
  • the refrigerant whose pressure is reduced by the expansion valve 240 and becomes a gas-liquid two-phase state passes through the outdoor heat exchanger 230.
  • the refrigerant that is evaporated and gasified by exchanging heat with outdoor air sent from the outdoor blower 250 passes through the four-way valve 220 and is sucked into the compressor 210 again.
  • the refrigerant of the air conditioner 1 is circulated, and air conditioning related to heating is performed.
  • Dotted arrows in FIG. 1 indicate the flow of refrigerant during cooling operation.
  • the high temperature and high pressure gas refrigerant compressed and discharged by the compressor 210 passes through the four-way valve 220 and flows into the outdoor heat exchanger 230.
  • the refrigerant passes through the outdoor heat exchanger 230 and exchanges heat with the outdoor air supplied by the outdoor blower 250, thereby condensing and liquefying.
  • the liquefied refrigerant passes through expansion valve 240.
  • the pressure is reduced and the refrigerant enters a gas-liquid two-phase state.
  • the refrigerant whose pressure is reduced by the expansion valve 240 and becomes a gas-liquid two-phase state passes through the indoor heat exchanger 110. Then, in the indoor heat exchanger 110, for example, the refrigerant that is evaporated and gasified by exchanging heat with the air in the air-conditioned space passes through the four-way valve 220 and is sucked into the compressor 210 again. As described above, the refrigerant of the air conditioner 1 circulates, and air conditioning related to cooling is performed.
  • the outdoor heat exchanger 230 performs a heating operation as an evaporator.
  • FIG. 2 is a diagram showing a schematic configuration of an example of the heat exchanger according to the first embodiment.
  • the heat exchanger in FIG. 2 is the outdoor heat exchanger 230, but it is also assumed that the indoor heat exchanger 110 has a similar configuration.
  • the outdoor heat exchanger 230 is, for example, a fin tube type heat exchanger.
  • the outdoor heat exchanger 230 has a heat exchanger main body 231 that exchanges heat between outdoor air and a refrigerant.
  • the heat exchanger main body 231 includes a plurality of heat exchanger tubes that serve as flow paths for the refrigerant and a plurality of fins that promote heat exchange between the refrigerant and outdoor air.
  • the heat exchanger main body 231 has one end connected to a refrigerant distributor 232 via a plurality of capillary tubes 233, and the other end connected to a header 234.
  • the distributor 232 and the header 234 distribute or join the refrigerant to the plurality of heat transfer tubes of the heat exchanger main body 231.
  • a two-phase pipe temperature sensor 500 and a liquid pipe temperature sensor 510 are attached to the outdoor heat exchanger 230.
  • the two-phase pipe temperature sensor 500 and the liquid pipe temperature sensor 510 are detection devices that detect the temperature of the refrigerant at the positions where they are installed and send signals related to the detection to the control device 400, which will be described later.
  • the two-phase pipe temperature sensor 500 detects the temperature of the refrigerant in the heat exchanger as the heat exchanger passing temperature.
  • the two-phase pipe temperature sensor 500 is attached so as to be able to detect the temperature of the refrigerant at a position approximately in the middle of the stroke through the heat exchanger main body 231. do.
  • the two-phase tube temperature sensor 500 is attached to a holder brazed to a U-shaped portion of a hairpin tube included in the heat exchanger body 231.
  • the position where the two-phase tube temperature sensor 500 is attached is, for example, a position where it is assumed that the temperature at point P3 in the ph diagram of FIG. 4, which will be described later, will be detected. Therefore, the heat exchanger passing temperature is usually the saturation temperature (evaporation temperature) of a gas-liquid two-phase refrigerant during the evaporation process of the refrigeration cycle.
  • the liquid pipe temperature sensor 510 is a detection device that detects the temperature of the refrigerant flowing into and out of the outdoor heat exchanger 230 as a liquid pipe temperature, and sends a signal related to the detection to the control device 400.
  • Liquid tube temperature sensor 510 detects the surface temperature of the outlet tube of the heat exchanger that functions as a condenser. The temperature corresponds to the temperature of the liquid refrigerant after condensation.
  • the heat exchanger functions as an evaporator
  • the liquid tube temperature sensor 510 detects the surface temperature of the inlet tube of the heat exchanger. The temperature corresponds to the temperature of a two-phase refrigerant with high wetness before evaporation.
  • the outdoor heat exchanger 230 when the outdoor heat exchanger 230 functions as an evaporator, it is a two-phase refrigerant temperature sensor that detects the temperature of a two-phase refrigerant with high humidity including liquid refrigerant flowing into the outdoor heat exchanger 230.
  • the liquid pipe temperature sensor 510 is attached via the refrigerant pipe 300 at a position that serves as a refrigerant flow path between the expansion valve 240 and the outdoor heat exchanger 230.
  • the liquid tube temperature sensor 510 is attached to a capillary tube 233 that connects the heat exchanger main body 231 and the distributor 232.
  • the outdoor heat exchanger 230 functions as a condenser
  • the liquid pipe temperature sensor 510 detects the temperature of the refrigerant flowing out from the outdoor heat exchanger 230.
  • FIG. 3 is a diagram illustrating the configuration of the control device 400 in the air conditioner 1 according to the first embodiment.
  • the control device 400 is a device that controls the air conditioner 1. Although the description here assumes that the outdoor unit 200 includes the control device 400, the present invention is not limited to this. Other units may include the control device 400. Further, the control device 400 may be a device independent from a unit having devices constituting the air conditioner 1.
  • the control device 400 includes a control section 410, a storage section 420, and a display section 430.
  • the control unit 410 includes, for example, a control processing unit such as a CPU (Central Processing Unit) or a microcomputer.
  • the control unit 410 in the first embodiment particularly includes a determination unit 411, a correction unit 412, a dry protection control unit 413, and a circulation amount estimation unit 414.
  • the determination unit 411 performs determination processing regarding dry protection control. For this reason, for example, the determination unit 411 includes a correction determination unit 411A that determines a correction value (degree of correction) to be corrected by the correction unit 412 with respect to the heat exchanger passing temperature detected by the two-phase pipe temperature sensor 500. .
  • the determination unit 411 includes a dry protection determination unit 411B that determines whether the dry protection control unit 413 performs dry protection control.
  • the correction unit 412 corrects the heat exchanger passage temperature using a correction value based on the determination by the correction determination unit 411A.
  • the dry protection control unit 413 performs dry protection control when the dry protection determining unit 411B determines that dry protection is to be performed.
  • the content of the dry protection control performed by the dry protection control section 413 is not particularly limited.
  • the dry protection control unit 413 performs control to lower the drive frequency of the compressor 210.
  • the dry protection control unit 413 performs control to lower the drive frequency of the compressor 210, thereby lowering the discharge temperature of the refrigerant discharged by the compressor 210, thereby protecting the compressor 210. Further, the dryness protection control unit 413 may stop the operation of the air conditioner 1 as dryness protection control.
  • the circulation amount estimation unit 414 then estimates the circulation amount of refrigerant passing through the heat exchanger serving as the evaporator. In the first embodiment, the circulation amount estimation unit 414 includes a drive frequency acquisition unit 414A, and estimates the circulation amount based on the obtained drive frequency of the compressor 210.
  • the storage unit 420 also includes, for example, a volatile storage device (not shown) such as a random access memory (RAM) that can temporarily store data, and a non-volatile auxiliary storage device (not shown) such as a flash memory.
  • a volatile storage device such as a random access memory (RAM) that can temporarily store data
  • a non-volatile auxiliary storage device such as a flash memory.
  • the storage unit 420 stores the relationship among the amount of refrigerant circulation, the evaporation temperature in the evaporator, and the correction value as data in a table format. It also stores data of a set threshold value used when the determination unit 411 makes a determination.
  • the set threshold value, correction value, etc. are set in advance through experiments or the like based on the refrigerant circulation amount and evaporation temperature.
  • the storage unit 420 has data in which a processing procedure performed by the control arithmetic processing device is a program.
  • the control unit 410 then executes processing based on the data of the program.
  • the control device 400 may be a device (hardware) dedicated to control.
  • the display unit 430 includes, for example, a display device such as a monitor that displays the status of the air conditioner 1 and the like.
  • the display section 430 performs a display related to dry protection.
  • FIG. 4 is a pH diagram of the refrigeration cycle device.
  • the temperature of the refrigerant which serves as a reference for determining the dry state of the refrigerant, is the heat exchanger passage temperature detected by the two-phase pipe temperature sensor 500 described above.
  • the two-phase tube temperature sensor 500 is arranged to detect the temperature of the refrigerant at a point P3 on the ph diagram (Mollier diagram) shown in FIG.
  • the pressure of the refrigerant in the evaporator is determined from point P3a, which is the refrigerant inlet of the evaporator, to point P3b, which is the refrigerant outlet, through point P3, and the pressure on the evaporator side (low pressure side of the refrigerant circuit).
  • a general characteristic of refrigerants is a tendency to decrease by the amount of loss.
  • FIG. 5 is a diagram showing the relationship between pressure and temperature in the evaporation process of a non-azeotropic mixed refrigerant when the pressure in the evaporator is constant in the refrigeration cycle device according to the first embodiment.
  • FIG. 6 is a diagram showing the relationship between pressure and temperature in the evaporation process of the non-azeotropic mixed refrigerant when a pressure difference occurs in the evaporator in the refrigeration cycle device according to the first embodiment.
  • the arrows shown in FIGS. 5 and 6 indicate the direction in which the refrigerant flows.
  • the boiling points of the refrigerants involved in the mixture are different. Therefore, the enthalpy increases and the temperature of the refrigerant also increases. Therefore, as shown in FIG. 5, for example, if there is no pressure difference or can be ignored between the pressure at point P3a and the pressure at point P3b, due to the physical properties of the non-azeotropic mixed refrigerant, the refrigerant inlet of the evaporator The temperature of the refrigerant increases from the point to the refrigerant outlet.
  • the liquid pipe temperature of the non-azeotropic mixed refrigerant tends to be lower than the heat exchanger passing temperature, as detected by the two-phase pipe temperature sensor 500.
  • a non-azeotropic mixed refrigerant even if the refrigerant is in a gas-liquid two-phase state in the evaporation process, it will exhibit the same temperature trend as a refrigerant in a superheated state.
  • refrigerant in a gas-liquid two-phase state flows within the evaporator at point P3, but if refrigerant leaks from the refrigerant circuit, there is a shortage of refrigerant in the refrigerant circuit. If so, the refrigerant may already be in an overheated state at point P3. In the case of a refrigerant that has a temperature gradient, it may be difficult to distinguish this from a refrigerant shortage condition.
  • the correction unit 412 corrects the heat exchanger passing temperature based on the determination by the determination unit 411.
  • FIG. 7 is a diagram showing a change in refrigerant temperature over time when the amount of refrigerant circulation is small in the outdoor heat exchanger 230 of the air conditioner 1 according to the first embodiment.
  • FIG. 8 is a diagram showing a temporal change in the refrigerant temperature when the amount of refrigerant circulation is large in the outdoor heat exchanger 230 of the air conditioner 1 according to the first embodiment.
  • the outdoor heat exchanger 230 here functions as an evaporator.
  • the pressure difference that occurs within the evaporator changes depending on the amount of refrigerant circulated. When the amount of refrigerant circulation is large, the pressure loss is large, and when the amount of refrigerant circulation is small, the pressure loss is small.
  • the determination unit 411 of the control device 400 determines whether the heat exchanger related to the temperature gradient is determined based on the heat exchanger passing temperature detected by the two-phase pipe temperature sensor 500. A correction value for the temperature passing through the chamber is determined and corrected by the correction unit 412. Then, the determination unit 411 of the control device 400 determines whether or not to perform dry protection based on the corrected heat exchanger passage temperature, and the dry protection control unit 413 performs dry protection control based on the determination. Therefore, the actual heat exchanger passing temperature detected by the two-phase pipe temperature sensor 500 can be corrected to a more accurate temperature. Therefore, the control device 400 of the air conditioner 1 can more accurately determine the dry state and perform dry protection control based on the determination. In addition, in the air conditioner 1 of the first embodiment, the control device 400 can more accurately determine the dryness protection based on the temperature of the refrigerant detected by the two-phase pipe temperature sensor 500 with a small number of temperature sensors. It can be carried out.
  • FIG. 9 is a diagram illustrating dry protection control processing of the refrigeration cycle device according to the second embodiment.
  • the processing in FIG. 9 will be described as being performed by the control device 400.
  • the circulation amount estimating section 414 of the control device 400 includes the driving frequency acquiring section 414A, as described above. Therefore, the circulation amount estimation unit 414 estimates the refrigerant circulation amount based on the drive frequency of the compressor 210 (step S1).
  • the refrigerant circulation amount can generally be obtained based on the following equation (1).
  • Refrigerant circulation amount volumetric efficiency x driving frequency x suction refrigerant density x displacement volume...(1)
  • the drive frequency is a term that affects when estimating the amount of refrigerant circulation. Therefore, in the second embodiment, when the circulation amount estimation unit 414 estimates the refrigerant circulation amount, it is assumed that the volumetric efficiency, the suction refrigerant density, and the displacement volume are constant values. Therefore, the amount of refrigerant circulation can be approximated as an amount that depends on the driving frequency of the compressor 210.
  • the correction determination unit 411A of the determination unit 411 compares the estimated refrigerant circulation amount with a set threshold value stored in the storage unit 420, and determines whether the refrigerant circulation amount is equal to or greater than the set threshold value. is determined (step S2).
  • the set threshold value is set, for example, to a value that provides a refrigerant circulation amount that is 50% of the maximum refrigerant circulation amount of the refrigerant passing through the indoor unit 100.
  • a set threshold value is set for the maximum refrigerant circulation amount in each indoor unit 100, respectively.
  • the correcting unit 412 corrects the heat exchanger passage temperature detected by the two-phase pipe temperature sensor 500 with the first correction value (Ste S3).
  • the correction determination unit 411A determines that the refrigerant circulation amount is smaller than the set threshold value, the heat exchanger detected by the two-phase pipe temperature sensor 500 will be The passing temperature is corrected (step S4).
  • the second correction value may be zero.
  • the correction unit 412 corrects the first correction value and the second correction value corresponding to the evaporation temperature.
  • the first correction value and the second correction value are stored in the storage unit 420 as data.
  • the dry protection determining unit 411B of the determining unit 411 determines whether to perform dry protection based on the corrected heat exchanger passage temperature (step S5). If the dry protection determining unit 411B determines that dry protection is not to be performed, the process returns to step S1.
  • the dry protection control unit 413 starts dry protection and performs processing related to dry protection control (step S6).
  • the content of the dry protection control performed by the dry protection control section 413 is not particularly limited.
  • the dry protection control unit 413 may first protect the compressor 210 by lowering the driving frequency of the compressor 210 and controlling the discharge temperature of the refrigerant discharged by the compressor 210. Further, the dry protection control unit 413 may stop the operation of the air conditioner 1. At this time, the display unit 430 of the control device 400 may display that dry protection control is being performed. When the dry protection control unit 413 of the control device 400 finishes the dry protection control, the process returns to step S1.
  • the effects described in the first embodiment can be obtained. Furthermore, in the air conditioner 1 according to the second embodiment, the control device 400 corrects the heat exchanger passage temperature based on the drive frequency. Therefore, a more accurate refrigerant circulation amount can be easily obtained.
  • FIG. 10 is a diagram showing the configuration of a control device 400 according to the third embodiment.
  • the circulation amount estimating section 414 of the control device 400 in the third embodiment includes an intake temperature determining section 414B.
  • the suction temperature determination unit 414B determines the suction temperature of the refrigerant sucked into the compressor 210 based on the heat exchanger passing temperature detected by the two-phase tube temperature sensor 500 attached to the evaporator.
  • the circulation amount estimation unit 414 of the second embodiment estimates the refrigerant circulation amount based on the drive frequency of the compressor 210 and the suction density based on the suction temperature determined by the suction temperature determination unit 414B.
  • the control device 400 determines and corrects the correction value based on the refrigerant circulation amount of the refrigerant circulating in the refrigerant circuit. Therefore, if the control device 400 can obtain a more accurate refrigerant circulation amount, it can perform more accurate correction.
  • the circulation amount estimation unit 414 of the control device 400 estimates the refrigerant circulation amount by setting the suction refrigerant density to a constant value.
  • Control device 400 in Embodiment 3 estimates the refrigerant circulation amount based not only on the drive frequency of compressor 210 but also on the suction refrigerant density obtained from the suction temperature of the refrigerant suctioned by compressor 210.
  • the control section 410 of the control device 400 includes the suction temperature determination section 414B, and determines the suction temperature based on the heat exchanger passage temperature. Therefore, the control device 400 can estimate the refrigerant circulation amount including the suction refrigerant density obtained from the suction temperature. Therefore, since the control device 400 can more accurately estimate the refrigerant circulation amount and make a determination, it can more accurately determine whether or not to perform dry protection control.
  • the refrigeration cycle device according to the third embodiment is the air conditioner 1 that performs air conditioning in a target space, it is possible to provide comfortable air conditioning for people in the room.
  • FIG. 11 is a diagram showing the configuration of a control device 400 according to the fourth embodiment.
  • Control device 400 in Embodiment 4 has suction temperature estimation section 414C.
  • the suction temperature estimation unit 414C estimates the suction temperature of the refrigerant sucked into the compressor 210 based on the opening degree of the expansion valve 240.
  • the circulation amount estimating section 414 of the fourth embodiment estimates the refrigerant circulation amount based on the drive frequency of the compressor 210 and the suction temperature estimated by the suction temperature estimating section 414C.
  • the suction temperature estimation unit 414C can obtain the Cv value of the expansion valve 240 based on the opening degree of the expansion valve 240.
  • the Cv value is a value determined by the type and port diameter of the expansion valve 240, and is the capacity coefficient of the valve.
  • the Cv value is a numerical representation of the flow rate of fluid passing through a valve at a given pressure difference.
  • the suction temperature estimating unit 414C estimates the low pressure on the low pressure side of the refrigerant circuit from the Cv value and the amount of refrigerant circulation, and further estimates the suction temperature.
  • the control device 400 can estimate not only the driving frequency of the compressor 210 but also the refrigerant circulation amount based on the estimated suction temperature.
  • the suction temperature estimating unit 414C of the control device 400 operates based on the opening degree of the expansion valve 240 that expands high-pressure refrigerant and depressurizes it to low-pressure refrigerant. , estimate the inlet temperature. Therefore, it is possible to obtain a more accurate amount of refrigerant circulation and make a determination, and control can be performed efficiently.
  • the refrigeration cycle device according to the fourth embodiment is the air conditioner 1 that performs air conditioning in a target space, comfortable air conditioning can be performed for people in the room.
  • control section 410 of the control device 400 has the suction temperature determination section 414B
  • control section 410 of the control device 400 has the suction temperature estimation section 414C. there were. However, it is not limited to those having either one of them.
  • the control unit 410 of the control device 400 may be configured to include both an intake temperature determination unit 414B and an intake temperature estimation unit 414C, and may perform respective processes.
  • the refrigeration cycle device of the first embodiment described above uses R454B refrigerant in which R32 refrigerant and R1234yf refrigerant are mixed at a ratio of 68.1:31.9 as the non-azeotropic mixed refrigerant that circulates in the refrigerant circuit.
  • R454B refrigerant in which R32 refrigerant and R1234yf refrigerant are mixed at a ratio of 68.1:31.9 as the non-azeotropic mixed refrigerant that circulates in the refrigerant circuit.
  • a non-azeotropic refrigerant mixture such as R407C may be used.
  • a pseudo-azeotropic refrigerant mixture having a temperature gradient may be used.
  • the refrigeration cycle device can be applied to various types of non-azeotropic mixed refrigerants, a refrigerant with a low GWP can be employed, and the refrigeration cycle device can be made in consideration of the global environment. Further, the refrigeration cycle device can be made compliant with the standards and standards of each region of the market.
  • the configuration of the refrigerant circuit in the refrigeration cycle device is not limited to the configuration of the air conditioner 1 in FIG. 1 described in the first embodiment described above.
  • the refrigeration cycle device may have an accumulator between the evaporator, which is the low-pressure side of the refrigerant circuit, and the suction side of the compressor 210.
  • the accumulator is a container that allows gas refrigerant to pass through and stores liquid refrigerant.
  • the refrigeration cycle device may have a receiver between the expansion valve 240 and a heat exchanger serving as a condenser on the high-pressure side of the refrigerant circuit.
  • the receiver is a container that stores excess refrigerant in the refrigerant circuit on the high-pressure side of the refrigerant circuit.
  • the heat exchanger passing temperature is corrected in the control device 400 using the first correction value or the second correction value based on the set threshold value, but the present invention is not limited to this.
  • the storage unit 420 may store a plurality of set threshold values as data so that the amount of refrigerant circulation is divided into three or more categories, and the correction value may be corrected using a correction value corresponding to each category. Further, if the relationship between the environmental state of the refrigerant during the evaporation process and the correction value can be expressed by a mathematical formula, the correction value may be calculated by calculation or the like.
  • the heat exchanger is used as the outdoor heat exchanger 230 of the outdoor unit 200, but the present invention is not limited to this. It may be used for the indoor heat exchanger 110 of the indoor unit 100, or may be used for both the outdoor heat exchanger 230 and the indoor heat exchanger 110.
  • the air conditioner 1 has been described, but the present invention can also be applied to other refrigeration cycle devices, such as a refrigerator, a freezing device, and a hot water supply device.
  • other refrigeration cycle devices such as a refrigerator, a freezing device, and a hot water supply device.
  • Air conditioner 100 Indoor unit, 110 Indoor heat exchanger, 120 Indoor blower, 200 Outdoor unit, 210 Compressor, 220 Four-way valve, 230 Outdoor heat exchanger, 231 Heat exchanger body, 232 Distributor, 233 Capillary tube , 234 header, 240 expansion valve, 250 outdoor blower, 300 refrigerant piping, 400 control device, 410 control unit, 411 determination unit, 411A correction determination unit, 411B dry protection determination unit, 412 correction unit, 413 dry protection control unit, 414 Circulation amount estimation section, 414A driving frequency acquisition section, 414B suction temperature determination section, 414C suction temperature estimation section, 420 storage section, 430 display section, 500 two-phase tube temperature sensor, 510 liquid tube temperature sensor.

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Abstract

The present invention provides a refrigeration cycle device including a refrigerant circuit which is formed by connecting a compressor, a condenser, an expansion valve, and an evaporator connected via pipes and which circulates a mixed refrigerant having a temperature gradient, the refrigeration cycle device comprising: a two-phase pipe temperature sensor that detects a heat exchanger passage temperature of the mixed refrigerant passing through the evaporator; and a control device that corrects the heat exchanger passage temperature detected by the two-phase pipe temperature sensor, determines whether to perform dry protection control on the basis of the corrected temperature, and performs the dry protection control on the basis of the determination.

Description

冷凍サイクル装置および空気調和装置Refrigeration cycle equipment and air conditioning equipment
 この技術は、冷凍サイクル装置および空気調和装置に係るものである。特に、温度勾配を有する冷媒を用いた冷媒回路における乾き保護制御に関するものである。 This technology relates to refrigeration cycle devices and air conditioners. In particular, the present invention relates to dry protection control in a refrigerant circuit using a refrigerant having a temperature gradient.
 空気調和装置などの冷凍サイクル装置は、冷媒回路内に充填された冷媒を循環させて、空気または水などの流体との熱交換を行い、流体を加熱または冷却する運転を行う。ここで、冷凍サイクル装置に用いられる冷媒において、地球温暖化係数(GWP:Global Warming Potential)が考慮される場合がある。地球温暖化係数が高い冷媒は、大気に放出されると、地球温暖化などの原因となる。このため、冷凍サイクル装置において用いられる冷媒は、環境への意識の高まりなどから、より地球温暖化係数の値が小さい冷媒へ移行していく傾向にある。そこで、近年、地球温暖化係数が低い冷媒として、沸点の異なる複数種の冷媒を混合した非共沸混合冷媒が用いられる。 A refrigeration cycle device such as an air conditioner circulates a refrigerant filled in a refrigerant circuit to exchange heat with a fluid such as air or water, thereby heating or cooling the fluid. Here, in the refrigerant used in the refrigeration cycle device, global warming potential (GWP) may be taken into consideration. Refrigerants with a high global warming potential cause global warming when released into the atmosphere. For this reason, there is a tendency for refrigerants used in refrigeration cycle devices to shift to refrigerants with lower global warming coefficients due to increased environmental awareness. Therefore, in recent years, a non-azeotropic mixed refrigerant, which is a mixture of multiple types of refrigerants with different boiling points, has been used as a refrigerant with a low global warming potential.
 また、冷凍サイクル装置の機器を制御する制御装置は、センサーなどの検出装置が検出した温度などの物理量および物理量からの演算などにより、蒸発温度の補正などが行われる(たとえば、特許文献1参照)。 In addition, the control device that controls the equipment of the refrigeration cycle device corrects the evaporation temperature by using physical quantities such as the temperature detected by a detection device such as a sensor, and calculations from the physical quantities (for example, see Patent Document 1). .
特開2018-185116号公報Japanese Patent Application Publication No. 2018-185116
 ここで、冷凍サイクル装置では、冷媒の乾き状態に基づいて、圧縮機の保護または冷媒量不足の判定などの乾き保護制御が行われる。しかしながら、特に、非共沸混合冷媒のように、温度勾配を有する冷媒を用いた冷媒回路の場合、蒸発過程における冷媒の温度が異なるため、適正な補正が行われない可能性があった。このため、蒸発過程における冷媒の過熱状態を正確に判定することができず、乾き保護制御を正確に行えない可能性があった。 Here, in the refrigeration cycle device, dry protection control such as protection of the compressor or determination of insufficient amount of refrigerant is performed based on the dry state of the refrigerant. However, especially in the case of a refrigerant circuit using a refrigerant having a temperature gradient, such as a non-azeotropic mixed refrigerant, the temperature of the refrigerant differs during the evaporation process, so there is a possibility that appropriate correction may not be performed. For this reason, the overheating state of the refrigerant during the evaporation process cannot be accurately determined, and there is a possibility that dry protection control cannot be performed accurately.
 そこで、温度勾配を有する冷媒を用いた場合でも、乾き保護制御をより正確に行うことができる冷凍サイクル装置および空気調和装置を得ることを目的とする。 Therefore, it is an object of the present invention to provide a refrigeration cycle device and an air conditioning device that can perform dry protection control more accurately even when using a refrigerant with a temperature gradient.
 この開示に係る冷凍サイクル装置は、圧縮機、凝縮器、膨張弁および蒸発器を配管接続して構成し、温度勾配を有する混合冷媒を循環させる冷媒回路を有する冷凍サイクル装置であって、蒸発器内を通過する混合冷媒の熱交換器通過温度を検出する二相管温度センサーと、二相管温度センサーが検出した熱交換器通過温度を補正し、補正した温度に基づいて乾き保護を行うかどうかを判定し、判定に基づいて乾き保護制御を行う制御装置とを備えるものである。 A refrigeration cycle device according to this disclosure has a refrigerant circuit configured by connecting a compressor, a condenser, an expansion valve, and an evaporator with piping, and circulates a mixed refrigerant having a temperature gradient. A two-phase pipe temperature sensor detects the temperature of the mixed refrigerant passing through the heat exchanger, and the two-phase pipe temperature sensor corrects the heat exchanger passing temperature, and performs dry protection based on the corrected temperature. and a control device that performs dry protection control based on the determination.
 また、この開示に係る空気調和装置は、上記の冷凍サイクル装置により、対象空間の冷暖房を行うものである。 Furthermore, the air conditioner according to this disclosure performs heating and cooling of a target space using the above-mentioned refrigeration cycle device.
 開示に係る冷凍サイクル装置および空気調和装置によれば、制御装置が、二相管温度センサーが検出した熱交換器通過温度を補正し、補正した温度に基づいて乾き保護制御を行うかどうかを判定し、判定に基づいて乾き保護制御を行う。このため、熱交換器通過温度を、より正確な温度に補正した上で、乾き保護制御を行うかどうかを判定することができる。したがって、冷凍サイクル装置は、より正確な乾き状態に基づいて、乾き保護制御を行うことができる。 According to the disclosed refrigeration cycle device and air conditioner, the control device corrects the heat exchanger passing temperature detected by the two-phase pipe temperature sensor, and determines whether to perform dry protection control based on the corrected temperature. Then, dry protection control is performed based on the judgment. Therefore, it is possible to determine whether or not to perform dry protection control after correcting the heat exchanger passing temperature to a more accurate temperature. Therefore, the refrigeration cycle device can perform dry protection control based on a more accurate dry state.
実施の形態1に係る冷凍サイクル装置の構成を示す図である。1 is a diagram showing the configuration of a refrigeration cycle device according to Embodiment 1. FIG. 実施の形態1に係る熱交換器の一例における概略構成を示す図である。1 is a diagram showing a schematic configuration of an example of a heat exchanger according to Embodiment 1. FIG. 実施の形態1に係る空気調和装置1における制御装置400の構成を説明する図である。FIG. 3 is a diagram illustrating the configuration of a control device 400 in the air conditioner 1 according to the first embodiment. 冷凍サイクル装置におけるp-h線図である。It is a pH diagram in a refrigeration cycle device. 実施の形態1に係る冷凍サイクル装置において蒸発器内の圧力一定における場合の非共沸混合冷媒による蒸発過程の圧力と温度の関係を示す図である。FIG. 3 is a diagram showing the relationship between pressure and temperature in the evaporation process of a non-azeotropic mixed refrigerant when the pressure in the evaporator is constant in the refrigeration cycle device according to the first embodiment. 実施の形態1に係る冷凍サイクル装置において蒸発器内に圧力差が生じる場合の非共沸混合冷媒による蒸発過程の圧力と温度の関係を示す図である。FIG. 3 is a diagram showing the relationship between pressure and temperature in the evaporation process of a non-azeotropic mixed refrigerant when a pressure difference occurs in the evaporator in the refrigeration cycle device according to the first embodiment. 実施の形態1に係る空気調和装置1の室外熱交換器230において、冷媒循環量が少ない場合における冷媒温度の時間変化を示す図である。FIG. 3 is a diagram showing a change in refrigerant temperature over time when the amount of refrigerant circulation is small in the outdoor heat exchanger 230 of the air conditioner 1 according to the first embodiment. 実施の形態1に係る空気調和装置1の室外熱交換器230において、冷媒循環量が多い場合における冷媒温度の時間変化を示す図である。FIG. 6 is a diagram showing a temporal change in refrigerant temperature when the amount of refrigerant circulation is large in the outdoor heat exchanger 230 of the air conditioner 1 according to the first embodiment. 実施の形態2に係る冷凍サイクル装置の乾き保護制御の処理について説明する図である。FIG. 7 is a diagram illustrating dry protection control processing of the refrigeration cycle device according to the second embodiment. 実施の形態3に係る制御装置400の構成を示す図である。3 is a diagram showing the configuration of a control device 400 according to Embodiment 3. FIG. 実施の形態4に係る制御装置400の構成を示す図である。FIG. 4 is a diagram showing the configuration of a control device 400 according to a fourth embodiment.
 以下、実施の形態に係る冷凍サイクル装置などについて、図面などを参照しながら説明する。以下の図面において、同一の符号を付したものは、同一またはこれに相当するものであり、以下に記載する実施の形態の全文において共通することとする。また、図面では各構成部材の大きさの関係が実際のものとは異なる場合がある。そして、明細書全文に表わされている構成要素の形態は、あくまでも例示であって、明細書に記載された形態に限定するものではない。特に構成要素の組み合わせは、各実施の形態における組み合わせのみに限定するものではなく、他の実施の形態に記載した構成要素を別の実施の形態に適用することができる。また、圧力および温度の高低については、特に絶対的な値との関係で高低が定まっているものではなく、装置などにおける状態および動作などにおいて相対的に定まるものとする。また、添字で区別などしている複数の同種の機器などについて、特に区別したり、特定したりする必要がない場合には、添字などを省略して記載する場合がある。 Hereinafter, refrigeration cycle devices and the like according to embodiments will be described with reference to drawings and the like. In the following drawings, the same reference numerals are the same or equivalent, and are common throughout the entire embodiment described below. Further, in the drawings, the size relationship of each component may differ from the actual one. The forms of the constituent elements shown in the entire specification are merely examples, and are not limited to the forms described in the specification. In particular, the combinations of components are not limited to those in each embodiment, and components described in other embodiments can be applied to other embodiments. In addition, the height of pressure and temperature is not determined particularly in relation to absolute values, but is determined relatively depending on the state and operation of the device etc. Additionally, if there is no need to distinguish or specify multiple devices of the same type that are distinguished by subscripts, the subscripts may be omitted from the description.
実施の形態1.
 図1は、実施の形態1に係る冷凍サイクル装置の構成を示す図である。ここでは、冷凍サイクル装置の一例として、空調対象空間となる室内の空気調和を行う空気調和装置1について説明する。図1に示すように、実施の形態1の空気調和装置1は、室外機200、室内機100および2本の冷媒配管300を有する。そして、室外機200が有する圧縮機210、四方弁220、室外熱交換器230および膨張弁240と室内機100が有する室内熱交換器110とが、冷媒配管300により配管接続され、冷媒を循環させて熱供給を行う冷媒回路を構成する。ここで、室内機100が膨張弁240を有する構成であってもよい。また、実施の形態1の空気調和装置1は、1台の室外機200と1台の室内機100が配管接続されて構成されているものとする。ただし、接続台数は、これに限定するものではない。
Embodiment 1.
FIG. 1 is a diagram showing the configuration of a refrigeration cycle device according to Embodiment 1. Here, as an example of a refrigeration cycle device, an air conditioner 1 that performs air conditioning in a room, which is a space to be air-conditioned, will be described. As shown in FIG. 1, the air conditioner 1 according to the first embodiment includes an outdoor unit 200, an indoor unit 100, and two refrigerant pipes 300. The compressor 210, four-way valve 220, outdoor heat exchanger 230, and expansion valve 240 of the outdoor unit 200 are connected to the indoor heat exchanger 110 of the indoor unit 100 by a refrigerant pipe 300, and the refrigerant is circulated. This constitutes a refrigerant circuit that supplies heat. Here, the indoor unit 100 may include the expansion valve 240. Furthermore, the air conditioner 1 according to the first embodiment is configured such that one outdoor unit 200 and one indoor unit 100 are connected by piping. However, the number of connected devices is not limited to this.
 また、ここでは、空気調和装置1は、冷媒回路内で循環する冷媒として、非共沸混合冷媒を用いる。非共沸混合冷媒とは、複数成分の冷媒を混合した冷媒のうち、蒸発および凝縮すると組成が変化する冷媒である。非共沸混合冷媒は、組成の変化に伴って、気液二相状態で同一圧力下であって、一定の温度に定まらない。たとえば、同一圧力下の蒸発過程において、非共沸混合冷媒は、蒸発開始における冷媒温度よりも蒸発終了における温度の方が高くなる。また、同一圧力下の凝縮過程において、非共沸混合冷媒は、凝縮開始における冷媒温度よりも凝縮終了における冷媒温度の方が低くなる。蒸発または凝縮の開始と終了とにおける温度差が温度勾配となる。ここで、実施の形態1における空気調和装置1で用いる非共沸混合冷媒は、HFC(ハイドロフルオロカーボン)冷媒であるR32冷媒とR1234yf冷媒とを、68.1:31.9の比率で混在したR454B冷媒であるものとする。 Furthermore, here, the air conditioner 1 uses a non-azeotropic mixed refrigerant as the refrigerant that circulates within the refrigerant circuit. A non-azeotropic mixed refrigerant is a refrigerant that is a mixture of multiple component refrigerants and whose composition changes when it evaporates and condenses. A non-azeotropic mixed refrigerant is in a gas-liquid two-phase state under the same pressure and does not settle at a constant temperature as the composition changes. For example, in the evaporation process under the same pressure, the temperature of the non-azeotropic mixed refrigerant at the end of evaporation is higher than the refrigerant temperature at the start of evaporation. Further, in the condensation process under the same pressure, the refrigerant temperature of the non-azeotropic mixed refrigerant at the end of condensation is lower than the refrigerant temperature at the start of condensation. The temperature difference between the start and end of evaporation or condensation is the temperature gradient. Here, the non-azeotropic mixed refrigerant used in the air conditioner 1 in the first embodiment is R454B, which is a mixture of R32 refrigerant and R1234yf refrigerant, which are HFC (hydrofluorocarbon) refrigerants, at a ratio of 68.1:31.9. It shall be a refrigerant.
 実施の形態1における室外機200は、冷媒回路を構成する機器として、圧縮機210、四方弁220および室外熱交換器230を有する。また、室外機200は、室外送風機250および制御装置400を有する。 Outdoor unit 200 in Embodiment 1 includes a compressor 210, a four-way valve 220, and an outdoor heat exchanger 230 as devices constituting a refrigerant circuit. Furthermore, the outdoor unit 200 includes an outdoor blower 250 and a control device 400.
 圧縮機210は、吸入した冷媒を圧縮して吐出する。圧縮機210は、たとえば、スクロール型圧縮機、ロータリ型圧縮機またはベーン型圧縮機などである。ここで、圧縮機210は、たとえば、インバータ回路などにより、駆動周波数を任意に変化させることにより、圧縮機210が吐出する冷媒の循環量を変化させることができる。 The compressor 210 compresses and discharges the sucked refrigerant. Compressor 210 is, for example, a scroll compressor, a rotary compressor, a vane compressor, or the like. Here, the compressor 210 can change the circulating amount of refrigerant discharged by the compressor 210 by arbitrarily changing the driving frequency using, for example, an inverter circuit.
 流路切替装置となる四方弁220は、たとえば、冷房運転と暖房運転とで冷媒の流れを切り換える弁である。四方弁220は、暖房運転が行われる際、圧縮機210の吐出側と室内熱交換器110とを接続するとともに、圧縮機210の吸引側と室外熱交換器230とを接続する。また、四方弁220は、冷房運転が行われる際、圧縮機210の吐出側と室外熱交換器230とを接続するとともに、圧縮機210の吸引側を室内熱交換器110と接続する。ここでは、四方弁220を用いた場合について例示しているが、流路切替装置はこれに限定されるものではない。たとえば、複数の二方弁などを組み合わせて流路切替装置としてもよい。 The four-way valve 220 serving as a flow path switching device is, for example, a valve that switches the flow of refrigerant between cooling operation and heating operation. The four-way valve 220 connects the discharge side of the compressor 210 and the indoor heat exchanger 110 and connects the suction side of the compressor 210 and the outdoor heat exchanger 230 when heating operation is performed. Furthermore, the four-way valve 220 connects the discharge side of the compressor 210 to the outdoor heat exchanger 230 and connects the suction side of the compressor 210 to the indoor heat exchanger 110 when cooling operation is performed. Here, a case is illustrated in which a four-way valve 220 is used, but the flow path switching device is not limited to this. For example, a flow path switching device may be formed by combining a plurality of two-way valves.
 室外熱交換器230は、冷媒と室外の空気との熱交換を行う熱交換器である。実施の形態1の室外熱交換器230は、暖房運転時においては蒸発器として機能し、冷媒を吸熱させて蒸発させ、ガス状の冷媒(以下、ガス冷媒という)に気化して通過させる。一方、冷房運転時においては、凝縮器として機能し、冷媒を凝縮して放熱させ、液状の冷媒(以下、液冷媒という)として液化して通過させる。室外熱交換器230の構成などについては、後に、さらに説明する。また、室外送風機250は、駆動により、室外機200外部からの空気を室外熱交換器230に通過させて室外機200内から流出させる空気の流れを形成し、室外熱交換器230における熱交換を促す。 The outdoor heat exchanger 230 is a heat exchanger that exchanges heat between the refrigerant and outdoor air. The outdoor heat exchanger 230 of Embodiment 1 functions as an evaporator during heating operation, absorbs heat from the refrigerant, evaporates it, and vaporizes the refrigerant into a gaseous refrigerant (hereinafter referred to as gas refrigerant). On the other hand, during cooling operation, it functions as a condenser, condenses the refrigerant, radiates heat, liquefies it as a liquid refrigerant (hereinafter referred to as liquid refrigerant), and passes it through. The configuration of the outdoor heat exchanger 230 will be further explained later. Furthermore, when driven, the outdoor blower 250 forms an air flow that causes air from outside the outdoor unit 200 to pass through the outdoor heat exchanger 230 and flow out from the outdoor unit 200, thereby facilitating heat exchange in the outdoor heat exchanger 230. prompt.
 絞り装置などとなる膨張弁240は、冷媒を減圧して膨張させる弁である。膨張弁240は、たとえば、電子式膨張弁などで構成する。そして、膨張弁240は、後述する制御装置400などの指示に基づいて開度を調整し、減圧を行い、冷媒の通過量を制御する。 The expansion valve 240, which serves as a throttle device or the like, is a valve that reduces the pressure of the refrigerant and expands it. The expansion valve 240 is, for example, an electronic expansion valve. The expansion valve 240 adjusts its opening based on instructions from a control device 400 or the like, which will be described later, to reduce the pressure and control the amount of refrigerant passing through.
 室内機100は、室内の空気調和を行う。室内機100は、冷媒回路を構成する機器として、室内熱交換器110を有する。また、室内機100は、室内送風機120を有する。室内熱交換器110は、空調対象空間である室内の空気と冷媒との熱交換を行う熱交換器である。たとえば、暖房運転時においては、室内熱交換器110は、凝縮器として機能し、冷媒を凝縮して液冷媒を通過させる。また、冷房運転時においては、室内熱交換器110は、蒸発器として機能し、冷媒を蒸発させてガス冷媒を通過させる。室内送風機120は、室内熱交換器110に空気を通過させて室内熱交換器110における熱交換を促し、室内熱交換器110を通過した空気を空調対象空間である室内に供給する。 The indoor unit 100 performs indoor air conditioning. The indoor unit 100 includes an indoor heat exchanger 110 as a device that constitutes a refrigerant circuit. Furthermore, the indoor unit 100 includes an indoor blower 120. The indoor heat exchanger 110 is a heat exchanger that exchanges heat between indoor air, which is a space to be air-conditioned, and a refrigerant. For example, during heating operation, indoor heat exchanger 110 functions as a condenser, condenses refrigerant, and passes liquid refrigerant. Further, during cooling operation, the indoor heat exchanger 110 functions as an evaporator, evaporates the refrigerant, and passes the gas refrigerant. The indoor blower 120 causes air to pass through the indoor heat exchanger 110 to promote heat exchange in the indoor heat exchanger 110, and supplies the air that has passed through the indoor heat exchanger 110 to the room that is the space to be air-conditioned.
 次に、空気調和装置1における各機器の動作について、冷媒の流れに基づいて説明する。まず、暖房運転における冷媒回路の各機器の動作を、冷媒の流れに基づいて説明する。図1の実線矢印は、暖房運転における冷媒の流れを示している。圧縮機210により圧縮されて吐出した高温および高圧のガス冷媒は、四方弁220を通過し、室内熱交換器110に流入する。ガス冷媒は、室内熱交換器110を通過中に、たとえば、空調対象空間の空気と熱交換することで凝縮し、液化する。凝縮し、液化した冷媒は、膨張弁240を通過する。冷媒は、膨張弁240を通過する際、減圧される。膨張弁240で減圧されて気液二相状態となった冷媒は、室外熱交換器230を通過する。室外熱交換器230において、室外送風機250から送られた室外の空気と熱交換することで蒸発し、ガス化した冷媒は、四方弁220を通過して、再度、圧縮機210に吸入される。以上のようにして、空気調和装置1の冷媒が循環し、暖房に係る空気調和を行う。 Next, the operation of each device in the air conditioner 1 will be explained based on the flow of refrigerant. First, the operation of each device in the refrigerant circuit during heating operation will be explained based on the flow of refrigerant. Solid line arrows in FIG. 1 indicate the flow of refrigerant during heating operation. The high temperature and high pressure gas refrigerant compressed and discharged by the compressor 210 passes through the four-way valve 220 and flows into the indoor heat exchanger 110. While passing through the indoor heat exchanger 110, the gas refrigerant condenses and liquefies, for example, by exchanging heat with the air in the air-conditioned space. The condensed and liquefied refrigerant passes through expansion valve 240 . When the refrigerant passes through the expansion valve 240, the pressure is reduced. The refrigerant whose pressure is reduced by the expansion valve 240 and becomes a gas-liquid two-phase state passes through the outdoor heat exchanger 230. In the outdoor heat exchanger 230, the refrigerant that is evaporated and gasified by exchanging heat with outdoor air sent from the outdoor blower 250 passes through the four-way valve 220 and is sucked into the compressor 210 again. As described above, the refrigerant of the air conditioner 1 is circulated, and air conditioning related to heating is performed.
 次に、冷房運転について説明する。図1の点線矢印は、冷房運転における冷媒の流れを示している。圧縮機210により圧縮されて吐出した高温および高圧のガス冷媒は、四方弁220を通過し、室外熱交換器230に流入する。そして、冷媒は、室外熱交換器230を通過して、室外送風機250が供給する室外の空気と熱交換することで凝縮し、液化する。液化した冷媒は、膨張弁240を通過する。ここで、冷媒は、膨張弁240を通過する際、減圧され、気液二相状態となる。膨張弁240で減圧されて気液二相状態となった冷媒は、室内熱交換器110を通過する。そして、室内熱交換器110において、たとえば、空調対象空間の空気と熱交換することで蒸発し、ガス化した冷媒は、四方弁220を通過して、再度、圧縮機210に吸入される。以上のようにして空気調和装置1の冷媒が循環し、冷房に係る空気調和を行う。ここで、以下の説明においては、室外熱交換器230が蒸発器となる暖房運転を行うものとして説明する。 Next, the cooling operation will be explained. Dotted arrows in FIG. 1 indicate the flow of refrigerant during cooling operation. The high temperature and high pressure gas refrigerant compressed and discharged by the compressor 210 passes through the four-way valve 220 and flows into the outdoor heat exchanger 230. Then, the refrigerant passes through the outdoor heat exchanger 230 and exchanges heat with the outdoor air supplied by the outdoor blower 250, thereby condensing and liquefying. The liquefied refrigerant passes through expansion valve 240. Here, when the refrigerant passes through the expansion valve 240, the pressure is reduced and the refrigerant enters a gas-liquid two-phase state. The refrigerant whose pressure is reduced by the expansion valve 240 and becomes a gas-liquid two-phase state passes through the indoor heat exchanger 110. Then, in the indoor heat exchanger 110, for example, the refrigerant that is evaporated and gasified by exchanging heat with the air in the air-conditioned space passes through the four-way valve 220 and is sucked into the compressor 210 again. As described above, the refrigerant of the air conditioner 1 circulates, and air conditioning related to cooling is performed. Here, in the following description, it is assumed that the outdoor heat exchanger 230 performs a heating operation as an evaporator.
 図2は、実施の形態1に係る熱交換器の一例における概略構成を示す図である。ここで、図2の熱交換器が室外熱交換器230であるものとして説明するが、室内熱交換器110についても同様の構成であるものとする。 FIG. 2 is a diagram showing a schematic configuration of an example of the heat exchanger according to the first embodiment. Here, the description will be made assuming that the heat exchanger in FIG. 2 is the outdoor heat exchanger 230, but it is also assumed that the indoor heat exchanger 110 has a similar configuration.
 室外熱交換器230は、たとえば、フィンチューブ型の熱交換器である。室外熱交換器230は、室外の空気と冷媒との熱交換を行う熱交換器本体231を有する。熱交換器本体231は、冷媒の流路となる複数の伝熱管および冷媒と室外の空気との熱交換を促進する複数のフィンで構成される。熱交換器本体231は、一端が複数のキャピラリチューブ233を介して冷媒の分配器232と接続され、他端がヘッダ234と接続される。分配器232およびヘッダ234は、熱交換器本体231の複数の伝熱管に冷媒を分配または合流させる。 The outdoor heat exchanger 230 is, for example, a fin tube type heat exchanger. The outdoor heat exchanger 230 has a heat exchanger main body 231 that exchanges heat between outdoor air and a refrigerant. The heat exchanger main body 231 includes a plurality of heat exchanger tubes that serve as flow paths for the refrigerant and a plurality of fins that promote heat exchange between the refrigerant and outdoor air. The heat exchanger main body 231 has one end connected to a refrigerant distributor 232 via a plurality of capillary tubes 233, and the other end connected to a header 234. The distributor 232 and the header 234 distribute or join the refrigerant to the plurality of heat transfer tubes of the heat exchanger main body 231.
 また、図2に示すように、室外熱交換器230には、二相管温度センサー500および液管温度センサー510が取り付けられる。二相管温度センサー500および液管温度センサー510は、取り付けられた位置における冷媒の温度を検出し、後述する制御装置400に、検出に係る信号を送る検出装置である。 Furthermore, as shown in FIG. 2, a two-phase pipe temperature sensor 500 and a liquid pipe temperature sensor 510 are attached to the outdoor heat exchanger 230. The two-phase pipe temperature sensor 500 and the liquid pipe temperature sensor 510 are detection devices that detect the temperature of the refrigerant at the positions where they are installed and send signals related to the detection to the control device 400, which will be described later.
 二相管温度センサー500は、熱交換器内における冷媒の温度を、熱交換器通過温度として検出する。特に限定するものではないが、ここでは、熱交換器本体231内を通過する行程のほぼ中間となる位置における冷媒の温度を検出できるように、二相管温度センサー500が取り付けられているものとする。たとえば、二相管温度センサー500は、熱交換器本体231が有するヘアピン管のU字部分などにロウ付けされたホルダーに取り付けられる。このように、二相管温度センサー500が取り付けられる位置は、たとえば、後述する図4のp-h線図におけるポイントP3の温度を検出することを想定した位置である。したがって、熱交換器通過温度は、通常、冷凍サイクルの蒸発過程における気液二相状態の冷媒での飽和温度(蒸発温度)となる。 The two-phase pipe temperature sensor 500 detects the temperature of the refrigerant in the heat exchanger as the heat exchanger passing temperature. Although not particularly limited, here, it is assumed that the two-phase pipe temperature sensor 500 is attached so as to be able to detect the temperature of the refrigerant at a position approximately in the middle of the stroke through the heat exchanger main body 231. do. For example, the two-phase tube temperature sensor 500 is attached to a holder brazed to a U-shaped portion of a hairpin tube included in the heat exchanger body 231. In this way, the position where the two-phase tube temperature sensor 500 is attached is, for example, a position where it is assumed that the temperature at point P3 in the ph diagram of FIG. 4, which will be described later, will be detected. Therefore, the heat exchanger passing temperature is usually the saturation temperature (evaporation temperature) of a gas-liquid two-phase refrigerant during the evaporation process of the refrigeration cycle.
 また、液管温度センサー510は、室外熱交換器230に流入出する冷媒の温度を液管温度として検出し、検出に係る信号を制御装置400に送る検出装置である。液管温度センサー510は、凝縮器として機能する熱交換器の出口管の表面温度を検出する。その温度は、凝縮後の液冷媒の温度に相当する。一方、熱交換器が蒸発器として機能する場合は、液管温度センサー510は、熱交換器の入口管の表面温度を検出する。その温度は、蒸発前の湿り度が大きい二相冷媒の温度に相当することとなる。ここでは、特に、室外熱交換器230が蒸発器として機能するときに、室外熱交換器230に流入する液冷媒を含む湿り度が大きい二相冷媒の温度を検出する二相冷媒温度センサーとなる。液管温度センサー510は、冷媒配管300を介して膨張弁240と室外熱交換器230との間における冷媒の流路となる位置に取り付けられる。ここでは、液管温度センサー510は、熱交換器本体231と分配器232とをつなぐキャピラリチューブ233に取り付けられる。室外熱交換器230が凝縮器として機能するときは、液管温度センサー510は、室外熱交換器230から流出する冷媒の温度を検出することになる。 Further, the liquid pipe temperature sensor 510 is a detection device that detects the temperature of the refrigerant flowing into and out of the outdoor heat exchanger 230 as a liquid pipe temperature, and sends a signal related to the detection to the control device 400. Liquid tube temperature sensor 510 detects the surface temperature of the outlet tube of the heat exchanger that functions as a condenser. The temperature corresponds to the temperature of the liquid refrigerant after condensation. On the other hand, when the heat exchanger functions as an evaporator, the liquid tube temperature sensor 510 detects the surface temperature of the inlet tube of the heat exchanger. The temperature corresponds to the temperature of a two-phase refrigerant with high wetness before evaporation. Here, in particular, when the outdoor heat exchanger 230 functions as an evaporator, it is a two-phase refrigerant temperature sensor that detects the temperature of a two-phase refrigerant with high humidity including liquid refrigerant flowing into the outdoor heat exchanger 230. . The liquid pipe temperature sensor 510 is attached via the refrigerant pipe 300 at a position that serves as a refrigerant flow path between the expansion valve 240 and the outdoor heat exchanger 230. Here, the liquid tube temperature sensor 510 is attached to a capillary tube 233 that connects the heat exchanger main body 231 and the distributor 232. When the outdoor heat exchanger 230 functions as a condenser, the liquid pipe temperature sensor 510 detects the temperature of the refrigerant flowing out from the outdoor heat exchanger 230.
 図3は、実施の形態1に係る空気調和装置1における制御装置400の構成を説明する図である。制御装置400は、空気調和装置1の制御を行う装置である。ここでは、室外機200が制御装置400を有するものとして説明するが、これに限定するものではない。他のユニットが制御装置400を有していてもよい。また、制御装置400が空気調和装置1を構成する機器を有するユニットから独立した装置であってもよい。 FIG. 3 is a diagram illustrating the configuration of the control device 400 in the air conditioner 1 according to the first embodiment. The control device 400 is a device that controls the air conditioner 1. Although the description here assumes that the outdoor unit 200 includes the control device 400, the present invention is not limited to this. Other units may include the control device 400. Further, the control device 400 may be a device independent from a unit having devices constituting the air conditioner 1.
 制御装置400は、制御部410、記憶部420および表示部430を有する。制御部410は、たとえば、CPU(Central Processing Unit)、マイクロコンピュータなどの制御演算処理装置を有する。実施の形態1における制御部410は、特に、判定部411、補正部412、乾き保護制御部413および循環量推定部414を有する。判定部411は、乾き保護制御に関する判定処理を行う。このため、たとえば、判定部411は、二相管温度センサー500が検出した熱交換器通過温度に対し、補正部412が補正を行う補正値(補正の度合い)を判定する補正判定部411Aを有する。また、判定部411は、乾き保護制御部413が乾き保護の制御を行うかどうかを判定する乾き保護判定部411Bを有する。補正部412は、補正判定部411Aの判定に基づく補正値で熱交換器通過温度を補正する。乾き保護制御部413は、乾き保護判定部411Bが乾き保護を行うと判定すると、乾き保護制御を行う。ここで、乾き保護制御部413が行う乾き保護制御の内容については、特に限定しない。たとえば、乾き保護制御部413は、圧縮機210の駆動周波数を下げる制御を行う。乾き保護制御部413が圧縮機210の駆動周波数を下げる制御を行うことで、圧縮機210が吐出する冷媒の吐出温度を下げて、圧縮機210の保護をはかる。また、乾き保護制御部413は、乾き保護制御として、空気調和装置1の運転を停止してもよい。そして、循環量推定部414は、蒸発器となる熱交換器を通過する冷媒の循環量を推定する。実施の形態1においては、循環量推定部414は、駆動周波数取得部414Aを有し、取得した圧縮機210の駆動周波数に基づいて循環量を推定する。 The control device 400 includes a control section 410, a storage section 420, and a display section 430. The control unit 410 includes, for example, a control processing unit such as a CPU (Central Processing Unit) or a microcomputer. The control unit 410 in the first embodiment particularly includes a determination unit 411, a correction unit 412, a dry protection control unit 413, and a circulation amount estimation unit 414. The determination unit 411 performs determination processing regarding dry protection control. For this reason, for example, the determination unit 411 includes a correction determination unit 411A that determines a correction value (degree of correction) to be corrected by the correction unit 412 with respect to the heat exchanger passing temperature detected by the two-phase pipe temperature sensor 500. . Further, the determination unit 411 includes a dry protection determination unit 411B that determines whether the dry protection control unit 413 performs dry protection control. The correction unit 412 corrects the heat exchanger passage temperature using a correction value based on the determination by the correction determination unit 411A. The dry protection control unit 413 performs dry protection control when the dry protection determining unit 411B determines that dry protection is to be performed. Here, the content of the dry protection control performed by the dry protection control section 413 is not particularly limited. For example, the dry protection control unit 413 performs control to lower the drive frequency of the compressor 210. The dry protection control unit 413 performs control to lower the drive frequency of the compressor 210, thereby lowering the discharge temperature of the refrigerant discharged by the compressor 210, thereby protecting the compressor 210. Further, the dryness protection control unit 413 may stop the operation of the air conditioner 1 as dryness protection control. The circulation amount estimation unit 414 then estimates the circulation amount of refrigerant passing through the heat exchanger serving as the evaporator. In the first embodiment, the circulation amount estimation unit 414 includes a drive frequency acquisition unit 414A, and estimates the circulation amount based on the obtained drive frequency of the compressor 210.
 また、記憶部420は、たとえば、データを一時的に記憶できるランダムアクセスメモリ(RAM)などの揮発性記憶装置(図示せず)およびフラッシュメモリなどの不揮発性の補助記憶装置(図示せず)を有する。ここでは、記憶部420は、冷媒循環量、蒸発器内における蒸発温度および補正値の関係を、テーブル形式のデータとして記憶する。また、判定部411が判定を行う際に利用する設定閾値のデータを記憶する。設定閾値、補正値などは、冷媒循環量および蒸発温度により、実験などによって、あらかじめ設定される。また、記憶部420には、制御演算処理装置が行う処理手順をプログラムとしたデータを有する。そして、制御部410がプログラムのデータに基づく処理を実行する。ただし、これに限定するものではなく、制御装置400が、制御専用の機器(ハードウェア)であってもよい。表示部430は、たとえば、空気調和装置1の状態などを表示するモニタなどの表示装置を有する。ここでは、表示部430は、乾き保護に係る表示を行う。 The storage unit 420 also includes, for example, a volatile storage device (not shown) such as a random access memory (RAM) that can temporarily store data, and a non-volatile auxiliary storage device (not shown) such as a flash memory. have Here, the storage unit 420 stores the relationship among the amount of refrigerant circulation, the evaporation temperature in the evaporator, and the correction value as data in a table format. It also stores data of a set threshold value used when the determination unit 411 makes a determination. The set threshold value, correction value, etc. are set in advance through experiments or the like based on the refrigerant circulation amount and evaporation temperature. Further, the storage unit 420 has data in which a processing procedure performed by the control arithmetic processing device is a program. The control unit 410 then executes processing based on the data of the program. However, the present invention is not limited to this, and the control device 400 may be a device (hardware) dedicated to control. The display unit 430 includes, for example, a display device such as a monitor that displays the status of the air conditioner 1 and the like. Here, the display section 430 performs a display related to dry protection.
 図4は、冷凍サイクル装置におけるp-h線図である。冷媒の乾き状態を判定する基準となる冷媒の温度は、前述した二相管温度センサー500が検出する熱交換器通過温度となる。二相管温度センサー500は、図4で示すp-h線図(モリエル線図)上のポイントP3における冷媒の温度を検出するように配置される。ここで、蒸発器内の冷媒の圧力は、蒸発器の冷媒流入口となるポイントP3aから、ポイントP3を経て、冷媒流出口となるポイントP3bへ、蒸発器側(冷媒回路の低圧側)の圧力損失分だけ低下していく傾向が、冷媒における一般的な特徴となる。 FIG. 4 is a pH diagram of the refrigeration cycle device. The temperature of the refrigerant, which serves as a reference for determining the dry state of the refrigerant, is the heat exchanger passage temperature detected by the two-phase pipe temperature sensor 500 described above. The two-phase tube temperature sensor 500 is arranged to detect the temperature of the refrigerant at a point P3 on the ph diagram (Mollier diagram) shown in FIG. Here, the pressure of the refrigerant in the evaporator is determined from point P3a, which is the refrigerant inlet of the evaporator, to point P3b, which is the refrigerant outlet, through point P3, and the pressure on the evaporator side (low pressure side of the refrigerant circuit). A general characteristic of refrigerants is a tendency to decrease by the amount of loss.
 図5は、実施の形態1に係る冷凍サイクル装置において蒸発器内の圧力一定における場合の非共沸混合冷媒による蒸発過程の圧力と温度の関係を示す図である。また、図6は、実施の形態1に係る冷凍サイクル装置において蒸発器内に圧力差が生じる場合の非共沸混合冷媒による蒸発過程の圧力と温度の関係を示す図である。図5および図6に示す矢印は、冷媒の流れる方向を示す。 FIG. 5 is a diagram showing the relationship between pressure and temperature in the evaporation process of a non-azeotropic mixed refrigerant when the pressure in the evaporator is constant in the refrigeration cycle device according to the first embodiment. Further, FIG. 6 is a diagram showing the relationship between pressure and temperature in the evaporation process of the non-azeotropic mixed refrigerant when a pressure difference occurs in the evaporator in the refrigeration cycle device according to the first embodiment. The arrows shown in FIGS. 5 and 6 indicate the direction in which the refrigerant flows.
 非共沸混合冷媒の場合、混合に係る冷媒における沸点がそれぞれ異なる。このため、エンタルピが上昇するとともに、冷媒の温度が上昇する。したがって、図5に示すように、たとえば、ポイントP3aにおける圧力とポイントP3bにおける圧力との間で、圧力差がないまたは無視できる場合は、非共沸混合冷媒の物性上、蒸発器の冷媒流入口から冷媒流出口にかけて冷媒の温度が上昇する。このため、非共沸混合冷媒は、二相管温度センサー500の検出に係る熱交換器通過温度よりも液管温度センサー510の検出に係る液管温度の方が低くなる傾向にある。そして、非共沸混合冷媒の場合は、蒸発過程にある気液二相状態の冷媒であっても、過熱状態にある冷媒と同様の温度傾向を示すこととなる。たとえば、正常な状態であれば、蒸発器内において、ポイントP3の位置では、気液二相状態の冷媒が流れるが、冷媒回路から冷媒が漏洩するなどして、冷媒回路において冷媒が不足している場合、ポイントP3において、すでに冷媒が過熱状態となる場合がある。温度勾配を有する冷媒の場合は、このような冷媒不足の状態との区別がつかない可能性がある。 In the case of non-azeotropic mixed refrigerants, the boiling points of the refrigerants involved in the mixture are different. Therefore, the enthalpy increases and the temperature of the refrigerant also increases. Therefore, as shown in FIG. 5, for example, if there is no pressure difference or can be ignored between the pressure at point P3a and the pressure at point P3b, due to the physical properties of the non-azeotropic mixed refrigerant, the refrigerant inlet of the evaporator The temperature of the refrigerant increases from the point to the refrigerant outlet. Therefore, the liquid pipe temperature of the non-azeotropic mixed refrigerant, as detected by the liquid pipe temperature sensor 510, tends to be lower than the heat exchanger passing temperature, as detected by the two-phase pipe temperature sensor 500. In the case of a non-azeotropic mixed refrigerant, even if the refrigerant is in a gas-liquid two-phase state in the evaporation process, it will exhibit the same temperature trend as a refrigerant in a superheated state. For example, under normal conditions, refrigerant in a gas-liquid two-phase state flows within the evaporator at point P3, but if refrigerant leaks from the refrigerant circuit, there is a shortage of refrigerant in the refrigerant circuit. If so, the refrigerant may already be in an overheated state at point P3. In the case of a refrigerant that has a temperature gradient, it may be difficult to distinguish this from a refrigerant shortage condition.
 一方で、図6に示すように、蒸発器内において生じる圧力損失などにより、蒸発器の冷媒流入口と冷媒流出口との間で圧力差が生じるなどの場合には、蒸発器の冷媒流入口から冷媒流出口にかけて冷媒の温度が一定または低下する。このため、圧力損失による冷媒の温度低下と非共沸混合冷媒の物性による温度上昇とが相殺する方向にはたらく。図6では、圧力損失による冷媒の温度低下と非共沸混合冷媒の物性による温度上昇とが釣り合って、蒸発器内における冷媒の温度が一定で推移する例を示している。図5および図6に示すように、非共沸混合冷媒のように温度勾配を有する冷媒においては、乾き保護の判定などを行う際に用いられる冷媒の温度は、一律ではない。このため、蒸発器内の圧力状態などに合わせた補正値で補正する必要があることがわかる。そこで、実施の形態1における空気調和装置1の制御装置400は、判定部411の判定に基づいて、補正部412が熱交換器通過温度を補正する。 On the other hand, as shown in Fig. 6, if a pressure difference occurs between the refrigerant inlet and the refrigerant outlet of the evaporator due to pressure loss occurring within the evaporator, the refrigerant inlet of the evaporator The temperature of the refrigerant remains constant or decreases from the refrigerant outlet to the refrigerant outlet. Therefore, the temperature decrease of the refrigerant due to pressure loss and the temperature increase due to the physical properties of the non-azeotropic mixed refrigerant work in a direction that offsets each other. FIG. 6 shows an example in which the temperature of the refrigerant in the evaporator remains constant because the temperature decrease of the refrigerant due to pressure loss and the temperature increase due to the physical properties of the non-azeotropic mixed refrigerant are balanced. As shown in FIGS. 5 and 6, in a refrigerant having a temperature gradient such as a non-azeotropic mixed refrigerant, the temperature of the refrigerant used when determining dry protection is not uniform. Therefore, it can be seen that it is necessary to perform correction using a correction value that matches the pressure state within the evaporator. Therefore, in the control device 400 of the air conditioner 1 in the first embodiment, the correction unit 412 corrects the heat exchanger passing temperature based on the determination by the determination unit 411.
 図7は、実施の形態1に係る空気調和装置1の室外熱交換器230において、冷媒循環量が少ない場合における冷媒温度の時間変化を示す図である。また、図8は、実施の形態1に係る空気調和装置1の室外熱交換器230において、冷媒循環量が多い場合における冷媒温度の時間変化を示す図である。前述したように、ここでは、室外熱交換器230は、蒸発器として機能する。冷媒回路において、蒸発器内に生じる圧力差は冷媒循環量によって変化する。冷媒循環量が多い場合には圧力損失が大きく、冷媒循環量が少ない場合には圧力損失が少なくなる。したがって、図7に示すように、冷媒循環量が少なく、圧力損失がないまたは少ない場合は、二相管温度センサー500が検出した温度に対する温度勾配を考慮した補正の値は大きくなる。一方、図8に示すように、冷媒循環量が多くなることで、圧力損失による温度低下と非共沸混合冷媒の物性による温度上昇とが生じる場合は、温度勾配を考慮した補正の値は小さい値でよい。 FIG. 7 is a diagram showing a change in refrigerant temperature over time when the amount of refrigerant circulation is small in the outdoor heat exchanger 230 of the air conditioner 1 according to the first embodiment. Moreover, FIG. 8 is a diagram showing a temporal change in the refrigerant temperature when the amount of refrigerant circulation is large in the outdoor heat exchanger 230 of the air conditioner 1 according to the first embodiment. As mentioned above, the outdoor heat exchanger 230 here functions as an evaporator. In the refrigerant circuit, the pressure difference that occurs within the evaporator changes depending on the amount of refrigerant circulated. When the amount of refrigerant circulation is large, the pressure loss is large, and when the amount of refrigerant circulation is small, the pressure loss is small. Therefore, as shown in FIG. 7, when the amount of refrigerant circulation is small and there is no or little pressure loss, the correction value that takes into account the temperature gradient with respect to the temperature detected by the two-phase pipe temperature sensor 500 becomes large. On the other hand, as shown in Figure 8, when an increase in the amount of refrigerant circulation causes a temperature drop due to pressure loss and a temperature rise due to the physical properties of the non-azeotropic mixed refrigerant, the correction value taking into account the temperature gradient is small. A value is fine.
 以上のように、実施の形態1の空気調和装置1によれば、制御装置400の判定部411が、二相管温度センサー500が検出する熱交換器通過温度に基づき、温度勾配に係る熱交換器通過温度の補正値を決定し、補正部412が補正する。そして、制御装置400の判定部411は、補正した熱交換器通過温度に基づき、乾き保護を行うかどうかを判定し、乾き保護制御部413が判定に基づいて乾き保護制御を行う。このため、二相管温度センサー500の検出に係る実際の熱交換器通過温度を、より正確な温度に補正することができる。このため、空気調和装置1の制御装置400は、乾き状態をより正確に判定し、判定に基づく乾き保護制御を行うことができる。また、実施の形態1の空気調和装置1は、制御装置400が、二相管温度センサー500が検出した冷媒の温度に基づき、少ない温度センサー数で、より正確に、乾き保護に係る判定などを行うことができる。 As described above, according to the air conditioner 1 of the first embodiment, the determination unit 411 of the control device 400 determines whether the heat exchanger related to the temperature gradient is determined based on the heat exchanger passing temperature detected by the two-phase pipe temperature sensor 500. A correction value for the temperature passing through the chamber is determined and corrected by the correction unit 412. Then, the determination unit 411 of the control device 400 determines whether or not to perform dry protection based on the corrected heat exchanger passage temperature, and the dry protection control unit 413 performs dry protection control based on the determination. Therefore, the actual heat exchanger passing temperature detected by the two-phase pipe temperature sensor 500 can be corrected to a more accurate temperature. Therefore, the control device 400 of the air conditioner 1 can more accurately determine the dry state and perform dry protection control based on the determination. In addition, in the air conditioner 1 of the first embodiment, the control device 400 can more accurately determine the dryness protection based on the temperature of the refrigerant detected by the two-phase pipe temperature sensor 500 with a small number of temperature sensors. It can be carried out.
実施の形態2.
 図9は、実施の形態2に係る冷凍サイクル装置の乾き保護制御の処理について説明する図である。図9における処理は、制御装置400が行うものとして説明する。制御装置400の循環量推定部414は、前述したように、駆動周波数取得部414Aを有する。そこで、循環量推定部414は、圧縮機210の駆動周波数に基づいて、冷媒循環量を推定する(ステップS1)。ここで、冷媒循環量は、一般的に、次式(1)に基づいて、得ることができる。
Embodiment 2.
FIG. 9 is a diagram illustrating dry protection control processing of the refrigeration cycle device according to the second embodiment. The processing in FIG. 9 will be described as being performed by the control device 400. The circulation amount estimating section 414 of the control device 400 includes the driving frequency acquiring section 414A, as described above. Therefore, the circulation amount estimation unit 414 estimates the refrigerant circulation amount based on the drive frequency of the compressor 210 (step S1). Here, the refrigerant circulation amount can generally be obtained based on the following equation (1).
 冷媒循環量=体積効率×駆動周波数×吸入冷媒密度×排除容積
                           …(1)
Refrigerant circulation amount = volumetric efficiency x driving frequency x suction refrigerant density x displacement volume...(1)
 (1)式において、駆動周波数が、冷媒循環量を推定する際に影響する項となる。そこで、実施の形態2では、循環量推定部414が冷媒循環量を推定する場合に、体積効率、吸入冷媒密度および排除容積は一定値であるとする。このため、冷媒循環量は、圧縮機210の駆動周波数に依存する量として概算の値を求めることができる。 In equation (1), the drive frequency is a term that affects when estimating the amount of refrigerant circulation. Therefore, in the second embodiment, when the circulation amount estimation unit 414 estimates the refrigerant circulation amount, it is assumed that the volumetric efficiency, the suction refrigerant density, and the displacement volume are constant values. Therefore, the amount of refrigerant circulation can be approximated as an amount that depends on the driving frequency of the compressor 210.
 制御装置400の判定部411では、判定部411の補正判定部411Aが、推定した冷媒循環量と記憶部420に記憶された設定閾値とを比較し、冷媒循環量が設定閾値以上であるかどうかを判定する(ステップS2)。設定閾値は、たとえば、室内機100を通過する冷媒の最大冷媒循環量に対し、50%となる冷媒循環量となる値が設定される。ここで、室内機100が複数ある場合には、各室内機100における最大冷媒循環量に対して、それぞれ設定閾値が設定される。補正判定部411Aが判定した結果、冷媒循環量が設定閾値以上であると判定すると、補正部412は、第1補正値で二相管温度センサー500が検出した熱交換器通過温度を補正する(ステップS3)。ここで、第1補正値は、補正をしない(補正値=0)の場合も含む。また、補正判定部411Aが判定した結果、冷媒循環量が設定閾値より小さいと判定すると、第1補正値よりも値が大きい第2補正値で、二相管温度センサー500が検出した熱交換器通過温度を補正する(ステップS4)。場合によっては、第2補正値が0となることもある。ここで、たとえば、蒸発温度が10℃のとき、共沸混合冷媒における温度勾配が1.5Kとなり、蒸発温度が5℃のとき、共沸混合冷媒における温度勾配が1.7Kとなるなど、そのときの運転における蒸発温度によって、温度勾配が異なる。したがって、補正部412は、蒸発温度に対応した第1補正値および第2補正値の値で補正する。第1補正値および第2補正値は、前述したように、記憶部420がデータとして記憶する。 In the determination unit 411 of the control device 400, the correction determination unit 411A of the determination unit 411 compares the estimated refrigerant circulation amount with a set threshold value stored in the storage unit 420, and determines whether the refrigerant circulation amount is equal to or greater than the set threshold value. is determined (step S2). The set threshold value is set, for example, to a value that provides a refrigerant circulation amount that is 50% of the maximum refrigerant circulation amount of the refrigerant passing through the indoor unit 100. Here, when there are a plurality of indoor units 100, a set threshold value is set for the maximum refrigerant circulation amount in each indoor unit 100, respectively. If the correction determining unit 411A determines that the refrigerant circulation amount is equal to or higher than the set threshold, the correcting unit 412 corrects the heat exchanger passage temperature detected by the two-phase pipe temperature sensor 500 with the first correction value ( Step S3). Here, the first correction value includes a case where no correction is made (correction value=0). Further, if the correction determination unit 411A determines that the refrigerant circulation amount is smaller than the set threshold value, the heat exchanger detected by the two-phase pipe temperature sensor 500 will be The passing temperature is corrected (step S4). In some cases, the second correction value may be zero. Here, for example, when the evaporation temperature is 10°C, the temperature gradient in the azeotropic mixed refrigerant is 1.5K, and when the evaporation temperature is 5°C, the temperature gradient in the azeotropic mixed refrigerant is 1.7K. The temperature gradient varies depending on the evaporation temperature during operation. Therefore, the correction unit 412 corrects the first correction value and the second correction value corresponding to the evaporation temperature. As described above, the first correction value and the second correction value are stored in the storage unit 420 as data.
 そして、判定部411の乾き保護判定部411Bは、補正した熱交換器通過温度に基づいて、乾き保護を行うかどうかを判定する(ステップS5)。乾き保護判定部411Bが乾き保護を行わないと判定すると、ステップS1に戻って処理を行う。 Then, the dry protection determining unit 411B of the determining unit 411 determines whether to perform dry protection based on the corrected heat exchanger passage temperature (step S5). If the dry protection determining unit 411B determines that dry protection is not to be performed, the process returns to step S1.
 一方、乾き保護判定部411Bが乾き保護を行うと判定すると、乾き保護制御部413は、乾き保護を開始し、乾き保護制御に係る処理を行う(ステップS6)。ここで、乾き保護制御部413が行う乾き保護制御の内容については、特に限定しない。たとえば、乾き保護制御部413は、圧縮機210の駆動周波数を下げ、圧縮機210が吐出する冷媒の吐出温度を下げる制御を行って、まず、圧縮機210の保護を行ってもよい。また、乾き保護制御部413は、空気調和装置1の運転を停止してもよい。このとき、制御装置400の表示部430は、乾き保護制御を行っている旨を表示するなどしてもよい。制御装置400の乾き保護制御部413が乾き保護制御を終了すると、ステップS1に戻って処理を行う。 On the other hand, when the dry protection determination unit 411B determines to perform dry protection, the dry protection control unit 413 starts dry protection and performs processing related to dry protection control (step S6). Here, the content of the dry protection control performed by the dry protection control section 413 is not particularly limited. For example, the dry protection control unit 413 may first protect the compressor 210 by lowering the driving frequency of the compressor 210 and controlling the discharge temperature of the refrigerant discharged by the compressor 210. Further, the dry protection control unit 413 may stop the operation of the air conditioner 1. At this time, the display unit 430 of the control device 400 may display that dry protection control is being performed. When the dry protection control unit 413 of the control device 400 finishes the dry protection control, the process returns to step S1.
 以上のように、実施の形態2の空気調和装置1によれば、実施の形態1において説明した効果を得ることができる。さらに、実施の形態2における空気調和装置1では、制御装置400が、駆動周波数に基づいて熱交換器通過温度を補正する。このため、より正確な冷媒循環量を容易に得ることができる。 As described above, according to the air conditioner 1 of the second embodiment, the effects described in the first embodiment can be obtained. Furthermore, in the air conditioner 1 according to the second embodiment, the control device 400 corrects the heat exchanger passage temperature based on the drive frequency. Therefore, a more accurate refrigerant circulation amount can be easily obtained.
実施の形態3.
 図10は、実施の形態3に係る制御装置400の構成を示す図である。図10に示す各部において、図3と同じ符号を付したものについては、実施の形態1で説明したことと同様の処理機能を果たす。実施の形態3における制御装置400の循環量推定部414は、吸入温度判定部414Bを有する。吸入温度判定部414Bは、蒸発器に取り付けられた二相管温度センサー500が検出した熱交換器通過温度に基づき、圧縮機210が吸入する冷媒の吸入温度を判定する。そして、実施の形態2の循環量推定部414は、圧縮機210の駆動周波数と吸入温度判定部414Bが判定した吸入温度による吸入密度とに基づいて、冷媒循環量を推定する。
Embodiment 3.
FIG. 10 is a diagram showing the configuration of a control device 400 according to the third embodiment. In each part shown in FIG. 10, those having the same reference numerals as in FIG. 3 perform the same processing functions as described in the first embodiment. The circulation amount estimating section 414 of the control device 400 in the third embodiment includes an intake temperature determining section 414B. The suction temperature determination unit 414B determines the suction temperature of the refrigerant sucked into the compressor 210 based on the heat exchanger passing temperature detected by the two-phase tube temperature sensor 500 attached to the evaporator. The circulation amount estimation unit 414 of the second embodiment estimates the refrigerant circulation amount based on the drive frequency of the compressor 210 and the suction density based on the suction temperature determined by the suction temperature determination unit 414B.
 実施の形態1および実施の形態2において説明したように、制御装置400は、冷媒回路を循環する冷媒の冷媒循環量に基づいて、補正値の判定および補正を行う。したがって、制御装置400は、より正確な冷媒循環量を得ることができれば、より正確な補正を行うことができる。ここで、実施の形態2では、制御装置400の循環量推定部414は、吸入冷媒密度を一定値として、冷媒循環量を推定した。実施の形態3における制御装置400は、圧縮機210の駆動周波数だけでなく、圧縮機210が吸入する冷媒の吸入温度により得られる吸入冷媒密度に基づいて冷媒循環量を推定する。 As described in the first and second embodiments, the control device 400 determines and corrects the correction value based on the refrigerant circulation amount of the refrigerant circulating in the refrigerant circuit. Therefore, if the control device 400 can obtain a more accurate refrigerant circulation amount, it can perform more accurate correction. Here, in the second embodiment, the circulation amount estimation unit 414 of the control device 400 estimates the refrigerant circulation amount by setting the suction refrigerant density to a constant value. Control device 400 in Embodiment 3 estimates the refrigerant circulation amount based not only on the drive frequency of compressor 210 but also on the suction refrigerant density obtained from the suction temperature of the refrigerant suctioned by compressor 210.
 以上のように、実施の形態3の冷凍サイクル装置によれば、制御装置400の制御部410は、吸入温度判定部414Bを有し、熱交換器通過温度に基づき、吸入温度を判定する。このため、制御装置400は、吸入温度から得られる吸入冷媒密度を含めて冷媒循環量を推定することができる。したがって、制御装置400は、より正確に冷媒循環量を推定して判定を行うことができるので、より正確に乾き保護制御を行うかどうかを判定することができる。そして、実施の形態3の冷凍サイクル装置が対象空間の空気調和を行う空気調和装置1である場合には、室内にいる人に快適な空気調和を行うことができる。 As described above, according to the refrigeration cycle device of the third embodiment, the control section 410 of the control device 400 includes the suction temperature determination section 414B, and determines the suction temperature based on the heat exchanger passage temperature. Therefore, the control device 400 can estimate the refrigerant circulation amount including the suction refrigerant density obtained from the suction temperature. Therefore, since the control device 400 can more accurately estimate the refrigerant circulation amount and make a determination, it can more accurately determine whether or not to perform dry protection control. When the refrigeration cycle device according to the third embodiment is the air conditioner 1 that performs air conditioning in a target space, it is possible to provide comfortable air conditioning for people in the room.
実施の形態4.
 図11は、実施の形態4に係る制御装置400の構成を示す図である。図11に示す各部において、図3と同じ符号を付したものについては、実施の形態1で説明したことと同様の処理機能を果たす。実施の形態4における制御装置400は、吸入温度推定部414Cを有する。吸入温度推定部414Cは、膨張弁240の開度に基づいて、圧縮機210が吸入する冷媒の吸入温度を推定する。そして、実施の形態4の循環量推定部414は、圧縮機210の駆動周波数と吸入温度推定部414Cが推定した吸入温度とに基づいて、冷媒循環量を推定する。
Embodiment 4.
FIG. 11 is a diagram showing the configuration of a control device 400 according to the fourth embodiment. In each part shown in FIG. 11, those with the same reference numerals as in FIG. 3 perform the same processing functions as described in the first embodiment. Control device 400 in Embodiment 4 has suction temperature estimation section 414C. The suction temperature estimation unit 414C estimates the suction temperature of the refrigerant sucked into the compressor 210 based on the opening degree of the expansion valve 240. The circulation amount estimating section 414 of the fourth embodiment estimates the refrigerant circulation amount based on the drive frequency of the compressor 210 and the suction temperature estimated by the suction temperature estimating section 414C.
 実施の形態4における冷凍サイクル装置では、制御装置400において、吸入温度推定部414Cは、膨張弁240の開度に基づき、膨張弁240のCv値を得ることができる。Cv値は、膨張弁240における弁の種類とポート径とによって決まる値であり、弁が有する容量係数である。Cv値は、ある差圧で弁を通過する流体の流量を数値で表したものである。また、吸入温度推定部414Cは、Cv値と冷媒循環量とから冷媒回路の低圧側における低圧圧力を推定し、さらに吸入温度を推定する。そして、制御装置400は、圧縮機210の駆動周波数だけでなく、さらに、推定した吸入温度に基づく冷媒循環量を推定することができる。 In the refrigeration cycle device according to the fourth embodiment, in the control device 400, the suction temperature estimation unit 414C can obtain the Cv value of the expansion valve 240 based on the opening degree of the expansion valve 240. The Cv value is a value determined by the type and port diameter of the expansion valve 240, and is the capacity coefficient of the valve. The Cv value is a numerical representation of the flow rate of fluid passing through a valve at a given pressure difference. Further, the suction temperature estimating unit 414C estimates the low pressure on the low pressure side of the refrigerant circuit from the Cv value and the amount of refrigerant circulation, and further estimates the suction temperature. The control device 400 can estimate not only the driving frequency of the compressor 210 but also the refrigerant circulation amount based on the estimated suction temperature.
 以上のように、実施の形態4の冷凍サイクル装置によれば、制御装置400の吸入温度推定部414Cは、高圧の冷媒を膨張させて低圧の冷媒に減圧させる膨張弁240の開度に基づいて、吸入温度を推定する。このため、より正確な冷媒循環量を得て判定を行うことができ、効率よく制御を行うことができる。そして、実施の形態4の冷凍サイクル装置が、対象空間の空気調和を行う空気調和装置1である場合には、室内にいる人に快適な空気調和を行うことができる。 As described above, according to the refrigeration cycle device of the fourth embodiment, the suction temperature estimating unit 414C of the control device 400 operates based on the opening degree of the expansion valve 240 that expands high-pressure refrigerant and depressurizes it to low-pressure refrigerant. , estimate the inlet temperature. Therefore, it is possible to obtain a more accurate amount of refrigerant circulation and make a determination, and control can be performed efficiently. When the refrigeration cycle device according to the fourth embodiment is the air conditioner 1 that performs air conditioning in a target space, comfortable air conditioning can be performed for people in the room.
実施の形態5.
 前述した実施の形態3では、制御装置400の制御部410は、吸入温度判定部414Bを有し、実施の形態4では、制御装置400の制御部410は、吸入温度推定部414Cを有するものであった。ただし、どちらかを有するものに限定しない。制御装置400の制御部410は、吸入温度判定部414Bおよび吸入温度推定部414Cを両方有する構成とし、それぞれの処理を行うようにしてもよい。
Embodiment 5.
In the third embodiment described above, the control section 410 of the control device 400 has the suction temperature determination section 414B, and in the fourth embodiment, the control section 410 of the control device 400 has the suction temperature estimation section 414C. there were. However, it is not limited to those having either one of them. The control unit 410 of the control device 400 may be configured to include both an intake temperature determination unit 414B and an intake temperature estimation unit 414C, and may perform respective processes.
 また、前述した実施の形態1の冷凍サイクル装置は、冷媒回路を循環する非共沸混合冷媒として、R32冷媒とR1234yf冷媒とが、68.1:31.9の比率で混在したR454B冷媒を用いた。しかしながら、これに限定するものではない。たとえば、R407Cなどの非共沸混合冷媒を用いてもよい。また、温度勾配を有する疑似共沸混合冷媒を用いてもよい。冷凍サイクル装置が、様々な種類の非共沸混合冷媒に適用することができるので、低GWPでの冷媒を採用することができ、地球環境を考慮した冷凍サイクル装置とすることができる。また、市場の地域ごとの規格および基準などに対応した冷凍サイクル装置とすることができる。 Further, the refrigeration cycle device of the first embodiment described above uses R454B refrigerant in which R32 refrigerant and R1234yf refrigerant are mixed at a ratio of 68.1:31.9 as the non-azeotropic mixed refrigerant that circulates in the refrigerant circuit. there was. However, it is not limited to this. For example, a non-azeotropic refrigerant mixture such as R407C may be used. Furthermore, a pseudo-azeotropic refrigerant mixture having a temperature gradient may be used. Since the refrigeration cycle device can be applied to various types of non-azeotropic mixed refrigerants, a refrigerant with a low GWP can be employed, and the refrigeration cycle device can be made in consideration of the global environment. Further, the refrigeration cycle device can be made compliant with the standards and standards of each region of the market.
 また、冷凍サイクル装置における冷媒回路の構成は、前述した実施の形態1で説明した図1における空気調和装置1の構成に限定するものではない。たとえば、冷凍サイクル装置が、冷媒回路の低圧側となる蒸発器と圧縮機210の吸入側との間にアキュムレータを有する構成としてもよい。アキュムレータは、ガス冷媒を通過させ、液冷媒を溜める容器である。また、冷凍サイクル装置が、冷媒回路の高圧側となる凝縮器となる熱交換器と膨張弁240との間にレシーバを有する構成としてもよい。レシーバは、冷媒回路の高圧側において、冷媒回路に余剰の冷媒を溜める容器である。 Furthermore, the configuration of the refrigerant circuit in the refrigeration cycle device is not limited to the configuration of the air conditioner 1 in FIG. 1 described in the first embodiment described above. For example, the refrigeration cycle device may have an accumulator between the evaporator, which is the low-pressure side of the refrigerant circuit, and the suction side of the compressor 210. The accumulator is a container that allows gas refrigerant to pass through and stores liquid refrigerant. Further, the refrigeration cycle device may have a receiver between the expansion valve 240 and a heat exchanger serving as a condenser on the high-pressure side of the refrigerant circuit. The receiver is a container that stores excess refrigerant in the refrigerant circuit on the high-pressure side of the refrigerant circuit.
 また、前述した実施の形態2では、制御装置400において、設定閾値に基づいて、第1補正値または第2補正値で熱交換器通過温度を補正したが、これに限定するものではない。記憶部420が、設定された複数の設定閾値をデータとして記憶し、冷媒循環量が3以上の区分に分かれるようにし、それぞれの区分に対応した補正値で補正してもよい。また、蒸発過程における冷媒の環境状態と補正値との関係が数式などで表せる場合には、演算などにより補正値を算出してもよい。 Furthermore, in the second embodiment described above, the heat exchanger passing temperature is corrected in the control device 400 using the first correction value or the second correction value based on the set threshold value, but the present invention is not limited to this. The storage unit 420 may store a plurality of set threshold values as data so that the amount of refrigerant circulation is divided into three or more categories, and the correction value may be corrected using a correction value corresponding to each category. Further, if the relationship between the environmental state of the refrigerant during the evaporation process and the correction value can be expressed by a mathematical formula, the correction value may be calculated by calculation or the like.
 前述した実施の形態1では、熱交換器を、室外機200の室外熱交換器230に用いたが、これに限定するものではない。室内機100の室内熱交換器110に用いてもよいし、室外熱交換器230および室内熱交換器110の両方に用いてもよい。 In the first embodiment described above, the heat exchanger is used as the outdoor heat exchanger 230 of the outdoor unit 200, but the present invention is not limited to this. It may be used for the indoor heat exchanger 110 of the indoor unit 100, or may be used for both the outdoor heat exchanger 230 and the indoor heat exchanger 110.
 前述した実施の形態1などにおいては、空気調和装置1について説明したが、たとえば、冷蔵装置、冷凍装置、給湯装置のように、他の冷凍サイクル装置にも適用することができる。 In Embodiment 1 and the like described above, the air conditioner 1 has been described, but the present invention can also be applied to other refrigeration cycle devices, such as a refrigerator, a freezing device, and a hot water supply device.
 1 空気調和装置、100 室内機、110 室内熱交換器、120 室内送風機、200 室外機、210 圧縮機、220 四方弁、230 室外熱交換器、231 熱交換器本体、232 分配器、233 キャピラリチューブ、234 ヘッダ、240 膨張弁、250 室外送風機、300 冷媒配管、400 制御装置、410 制御部、411 判定部、411A 補正判定部、411B 乾き保護判定部、412 補正部、413 乾き保護制御部、414 循環量推定部、414A 駆動周波数取得部、414B 吸入温度判定部、414C 吸入温度推定部、420 記憶部、430 表示部、500 二相管温度センサー、510 液管温度センサー。 1 Air conditioner, 100 Indoor unit, 110 Indoor heat exchanger, 120 Indoor blower, 200 Outdoor unit, 210 Compressor, 220 Four-way valve, 230 Outdoor heat exchanger, 231 Heat exchanger body, 232 Distributor, 233 Capillary tube , 234 header, 240 expansion valve, 250 outdoor blower, 300 refrigerant piping, 400 control device, 410 control unit, 411 determination unit, 411A correction determination unit, 411B dry protection determination unit, 412 correction unit, 413 dry protection control unit, 414 Circulation amount estimation section, 414A driving frequency acquisition section, 414B suction temperature determination section, 414C suction temperature estimation section, 420 storage section, 430 display section, 500 two-phase tube temperature sensor, 510 liquid tube temperature sensor.

Claims (6)

  1.  圧縮機、凝縮器、膨張弁および蒸発器を配管接続して構成し、温度勾配を有する混合冷媒を循環させる冷媒回路を有する冷凍サイクル装置であって、
     前記蒸発器内を通過する前記混合冷媒の熱交換器通過温度を検出する二相管温度センサーと、
     前記二相管温度センサーが検出した前記熱交換器通過温度を補正し、補正した温度に基づいて乾き保護を行うかどうかを判定し、判定に基づいて乾き保護制御を行う制御装置と
    を備える冷凍サイクル装置。
    A refrigeration cycle device having a refrigerant circuit configured by connecting a compressor, a condenser, an expansion valve, and an evaporator with piping and circulating a mixed refrigerant having a temperature gradient,
    a two-phase pipe temperature sensor that detects a heat exchanger passage temperature of the mixed refrigerant passing through the evaporator;
    A refrigeration system comprising: a control device that corrects the heat exchanger passage temperature detected by the two-phase pipe temperature sensor, determines whether to perform dry protection based on the corrected temperature, and performs dry protection control based on the determination. cycle equipment.
  2.  前記制御装置は、
     前記圧縮機の駆動周波数を取得する駆動周波数取得部を有し、前記駆動周波数に基づいて前記混合冷媒の冷媒循環量を推定する循環量推定部と、
     推定した前記冷媒循環量とあらかじめ定めた設定閾値とに基づいて、前記二相管温度センサーが検出した前記熱交換器通過温度の補正値を判定する補正判定部と、
     前記補正判定部の判定に基づいて前記熱交換器通過温度を補正する補正部と、
     補正した前記熱交換器通過温度に基づいて乾き保護を行うかどうかを判定する乾き保護判定部と、
     前記乾き保護判定部が乾き保護を行うと判定すると、乾き保護制御を行う乾き保護制御部と
    を有する請求項1に記載の冷凍サイクル装置。
    The control device includes:
    a circulation amount estimation section that includes a drive frequency acquisition section that acquires a drive frequency of the compressor, and that estimates a refrigerant circulation amount of the mixed refrigerant based on the drive frequency;
    a correction determination unit that determines a correction value for the heat exchanger passage temperature detected by the two-phase pipe temperature sensor based on the estimated refrigerant circulation amount and a predetermined set threshold;
    a correction unit that corrects the heat exchanger passing temperature based on a determination by the correction determination unit;
    a dry protection determination unit that determines whether to perform dry protection based on the corrected heat exchanger passing temperature;
    The refrigeration cycle device according to claim 1, further comprising a dry protection control unit that performs dry protection control when the dry protection determination unit determines to perform dry protection.
  3.  前記循環量推定部は、
     前記二相管温度センサーが検出した前記熱交換器通過温度から前記圧縮機の吸入温度を判定する吸入温度判定部をさらに有し、
     前記駆動周波数と前記吸入温度とに基づいて、前記冷媒循環量を推定する請求項2に記載の冷凍サイクル装置。
    The circulation amount estimating unit is
    further comprising a suction temperature determination unit that determines the suction temperature of the compressor from the heat exchanger passing temperature detected by the two-phase pipe temperature sensor,
    The refrigeration cycle device according to claim 2, wherein the refrigerant circulation amount is estimated based on the drive frequency and the suction temperature.
  4.  前記循環量推定部は、
     前記膨張弁の開度から前記圧縮機の吸入温度を推定する吸入温度推定部をさらに有し、前記駆動周波数と前記吸入温度とに基づいて、前記冷媒循環量を推定する請求項2または請求項3に記載の冷凍サイクル装置。
    The circulation amount estimating unit is
    Claim 2 or Claim 2, further comprising a suction temperature estimator that estimates the suction temperature of the compressor from the opening degree of the expansion valve, and estimates the refrigerant circulation amount based on the drive frequency and the suction temperature. 3. The refrigeration cycle device according to 3.
  5.  前記温度勾配を有する前記混合冷媒は、R32冷媒とR1234yf冷媒とを混合した非共沸混合冷媒である請求項1~請求項4のいずれか一項に記載の冷凍サイクル装置。 The refrigeration cycle device according to any one of claims 1 to 4, wherein the mixed refrigerant having the temperature gradient is a non-azeotropic mixed refrigerant that is a mixture of R32 refrigerant and R1234yf refrigerant.
  6.  請求項1~請求項5のいずれか一項に記載の冷凍サイクル装置により、対象空間の冷暖房を行う空気調和装置。 An air conditioner that performs heating and cooling of a target space using the refrigeration cycle device according to any one of claims 1 to 5.
PCT/JP2022/032912 2022-09-01 2022-09-01 Refrigeration cycle device and air conditioning device WO2024047832A1 (en)

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Citations (5)

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Publication number Priority date Publication date Assignee Title
JPH08320158A (en) * 1995-05-26 1996-12-03 Matsushita Refrig Co Ltd Air conditioner
JP2011179746A (en) * 2010-03-01 2011-09-15 Mitsubishi Electric Corp Air conditioner and method of suppressing and controlling high pressure of the same
JP2012220042A (en) * 2011-04-04 2012-11-12 Mitsubishi Electric Corp Air conditioning apparatus
JP2017053566A (en) * 2015-09-10 2017-03-16 ジョンソンコントロールズ ヒタチ エア コンディショニング テクノロジー(ホンコン)リミテッド Refrigeration cycle device
JP2021014962A (en) * 2019-07-12 2021-02-12 ダイキン工業株式会社 Indoor unit of refrigeration device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08320158A (en) * 1995-05-26 1996-12-03 Matsushita Refrig Co Ltd Air conditioner
JP2011179746A (en) * 2010-03-01 2011-09-15 Mitsubishi Electric Corp Air conditioner and method of suppressing and controlling high pressure of the same
JP2012220042A (en) * 2011-04-04 2012-11-12 Mitsubishi Electric Corp Air conditioning apparatus
JP2017053566A (en) * 2015-09-10 2017-03-16 ジョンソンコントロールズ ヒタチ エア コンディショニング テクノロジー(ホンコン)リミテッド Refrigeration cycle device
JP2021014962A (en) * 2019-07-12 2021-02-12 ダイキン工業株式会社 Indoor unit of refrigeration device

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