WO2019021428A1 - Refrigeration and air conditioning device, and control device - Google Patents

Refrigeration and air conditioning device, and control device Download PDF

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Publication number
WO2019021428A1
WO2019021428A1 PCT/JP2017/027288 JP2017027288W WO2019021428A1 WO 2019021428 A1 WO2019021428 A1 WO 2019021428A1 JP 2017027288 W JP2017027288 W JP 2017027288W WO 2019021428 A1 WO2019021428 A1 WO 2019021428A1
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WO
WIPO (PCT)
Prior art keywords
refrigerant
temperature
azeotropic
refrigeration air
low pressure
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PCT/JP2017/027288
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French (fr)
Japanese (ja)
Inventor
昌彦 中川
七種　哲二
Original Assignee
三菱電機株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
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Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to JP2019532298A priority Critical patent/JP7058657B2/en
Priority to CN201790001747.6U priority patent/CN212253263U/en
Priority to PCT/JP2017/027288 priority patent/WO2019021428A1/en
Publication of WO2019021428A1 publication Critical patent/WO2019021428A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B1/00—Compression machines, plants or systems with non-reversible cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems

Definitions

  • the present invention relates to a refrigeration air conditioning apparatus and a control apparatus provided with a control apparatus that determines the presence or absence of leakage of a refrigerant sealed in a refrigerant circuit.
  • Patent Document 1 discloses a method of detecting a shortage of refrigerant in a refrigeration circuit which is generated due to the leakage of the refrigerant or the like.
  • Patent Document 1 it is assumed that the difference between the theoretical inlet temperature of the evaporator, which is determined by the heat load when it is assumed that the refrigerant is sufficiently present in the refrigeration circuit, and the inlet temperature of the evaporator actually measured When the above state continues for a fixed period, it is determined that the refrigerant is insufficient.
  • the refrigerant shortage detection method disclosed in Patent Document 1 detects refrigerant leakage using a change in state quantity due to a pressure drop.
  • the threshold value for determining the pressure drop also changes, so it is difficult to detect the refrigerant leakage with high accuracy.
  • the present invention has been made to solve the above problems, and provides a refrigeration air conditioner and a control device capable of detecting the leakage of refrigerant without depending on the pipe length of the refrigerant circuit. is there.
  • the compressor, the condenser, the expansion unit, and the evaporator are connected by piping, and the temperature of the low-pressure non-azeotropic refrigerant in the refrigerant circuit and the refrigerant circuit in which the non-azeotropic refrigerant circulates is detected
  • the refrigerant circuit is operated under an inspection condition for maintaining the low pressure of the refrigerant circuit at the set pressure, and the inspection mode is used to determine the presence or absence of non-azeotropic refrigerant leakage using the temperature detected by the low pressure temperature sensor.
  • a controller is used to determine the presence or absence of non-azeotropic refrigerant leakage using the temperature detected by the low pressure temperature sensor.
  • the refrigerant circuit is operated under the inspection condition for keeping the low pressure of the refrigerant circuit at the set pressure, and the state of the refrigerant circuit is stabilized. Therefore, the low pressure is maintained at the set pressure regardless of the pipe length of the refrigerant circuit, so the state of the refrigerant circuit can be stabilized regardless of the pipe length of the refrigerant circuit. Therefore, the leakage of the refrigerant can be accurately detected regardless of the pipe length of the refrigerant circuit.
  • FIG. 7 is a ph diagram showing the state in the inspection mode in the first embodiment of the present invention. It is a table
  • FIG. 1 is a circuit diagram showing a refrigerating and air-conditioning apparatus 100 according to Embodiment 1 of the present invention.
  • the refrigeration air conditioner 100 will be described based on FIG.
  • the refrigeration air conditioning system 100 is an apparatus for cooling a cooling object such as a refrigerator, and includes a refrigerant circuit 10, a condensation temperature sensor 21, an expansion inlet temperature sensor 22, and a low pressure pressure sensor 23. , And an evaporation inlet temperature sensor 24 and a controller 50.
  • the compressor 11, the condenser 12, the expansion unit 13, the evaporator 14, and the accumulator 15 are connected by piping, and a non-azeotropic refrigerant in which refrigerants having different boiling points are mixed circulates.
  • the compressor 11 sucks and compresses the non-azeotropic refrigerant in the low temperature and low pressure state and discharges the non-azeotropic refrigerant in the high temperature and high pressure state.
  • the compressor 11 is, for example, an inverter compressor capable of controlling the capacity.
  • the condenser 12 exchanges heat, for example, between outdoor air and a non-azeotropic refrigerant.
  • the expansion unit 13 is a pressure reducing valve or an expansion valve that decompresses and expands a non-azeotropic refrigerant.
  • the expansion portion 13 is, for example, an electronic expansion valve whose opening degree is adjusted.
  • the evaporator 14 cools the cooling chamber, for example, to exchange heat between the air in the cooling chamber and the non-azeotropic refrigerant.
  • the accumulator 15 separates the gas refrigerant and the liquid refrigerant, and stores the surplus refrigerant which has become surplus among the non-azeotropic refrigerant flowing in the refrigerant circuit 10.
  • the refrigeration air conditioning apparatus 100 may include a flow path switching unit that switches the flow direction of the non-azeotropic refrigerant flowing in the refrigerant circuit 10. In this case, the refrigeration air conditioning apparatus 100 can execute both the cooling operation and the heating operation.
  • the cooling operation of the refrigeration air conditioner 100 will be described.
  • the refrigerant drawn into the compressor 11 is compressed by the compressor 11 and discharged in a high-temperature high-pressure gas state.
  • the high-temperature high-pressure gas refrigerant discharged from the compressor 11 flows into the condenser 12, and in the condenser 12, it exchanges heat with outdoor air, condenses, and liquefies.
  • the condensed refrigerant in the liquid state flows into the expansion unit 13 and is expanded and reduced in pressure in the expansion unit 13 to become a low-temperature low-pressure gas-liquid two-phase refrigerant.
  • the refrigerant in the gas-liquid two-phase state flows into the evaporator 14, and in the evaporator 14, it exchanges heat with the air in the cooling chamber to evaporate and gasify. At this time, the cooling chamber is cooled. The evaporated low-temperature low-pressure gas refrigerant is drawn into the compressor 11.
  • the condensation temperature sensor 21 detects the condensation temperature of the non-azeotropic refrigerant flowing to the condenser 12.
  • the expansion inlet temperature sensor 22 is provided on the inlet side of the expansion portion 13 and detects the temperature before expansion of the non-azeotropic refrigerant flowing to the inlet side of the expansion portion 13.
  • the low pressure sensor 23 is provided on the inlet side of the evaporator 14 and detects the low pressure of the non-azeotropic refrigerant flowing to the inlet side of the evaporator 14.
  • the evaporation inlet temperature sensor 24 is provided on the inlet side of the evaporator 14 and detects the inlet temperature of the non-azeotropic refrigerant flowing to the inlet side of the evaporator 14.
  • the evaporation inlet temperature sensor 24 corresponds to a low pressure temperature sensor.
  • FIG. 2 is a table showing the boiling point and the composition ratio of the refrigerant that constitutes R407C, which is the non-azeotropic refrigerant in the first embodiment of the present invention.
  • the non-azeotropic refrigerant sealed in the refrigerant circuit 10 is R407C.
  • R407C is a mixture of R32, R125 and R134a.
  • the boiling points are as follows: R32 is -51.7 ° C, R125 is -48.1 ° C, and R134a is -26.1 ° C. That is, among the refrigerants constituting R407C, the boiling point of R134a is the highest.
  • the composition ratio is 23% for R32, 25% for R125, and 52% for R134a.
  • the non-azeotropic refrigerant stored in the accumulator 15 is mainly a liquid refrigerant separated from the gas refrigerant, and the refrigerant stored in the accumulator 15 has a high ratio of R134a which is difficult to be gasified because the boiling point is high. For this reason, the refrigerant circulating in the refrigerant circuit 10 has a high ratio of R32 and R125.
  • the refrigerant density of the non-azeotropic refrigerant changes as the high pressure side pressure and the low pressure side pressure change due to seasonal fluctuation or cooling load fluctuation.
  • the high pressure side pressure refers to the pressure of the high pressure refrigerant compressed by the compressor 11
  • the low pressure side pressure refers to the pressure of the low pressure refrigerant expanded in the expansion unit 13. Therefore, the amount of refrigerant required in the refrigerant circuit 10 also changes.
  • the refrigerant having the amount of the refrigerant required above the maximum amount of refrigerant in consideration of the change in the amount of refrigerant necessary is enclosed so that the capacity loss due to the refrigerant shortage and the overheating operation do not occur under any circumstances. Be done. Therefore, surplus refrigerant generated due to the change of the required refrigerant amount is stored in the accumulator 15.
  • the control device 50 controls the refrigeration air conditioner 100 based on measured values of pressure and temperature of each part and various set values.
  • the control device 50 grasps the operating state of the refrigeration air conditioner 100 based on the pressure and temperature acquired from the condensation temperature sensor 21, the expansion inlet temperature sensor 22, the low pressure sensor 23, and the evaporation inlet temperature sensor 24.
  • the control device 50 adjusts the high pressure according to the temperature of the outdoor air sucked into the condenser 12, the amount of cooling air of the condenser 12, the size of the cooling load, and the power consumption of the compressor 11.
  • control device 50 adjusts the low pressure according to the operating frequency of the compressor 11, the amount of cooling air of the evaporator 14, the opening degree of the expansion portion 13 and the like, and maintains the degree of superheat at the outlet of the evaporator 14 at the set degree of superheat.
  • the controller 50 has an inspection mode for detecting a refrigerant leak, in addition to the normal operation mode for air conditioning the cooling chamber.
  • the inspection mode is a mode in which the refrigerant circuit 10 is operated under inspection conditions for keeping the low pressure of the refrigerant circuit 10 at the set pressure, and the presence or absence of the non-azeotropic refrigerant leakage is determined.
  • the controller 50 executes the inspection mode under the condition that continuous operation for a relatively long time is possible. For example, the inspection mode is performed when the temperature of the cooling chamber is higher than the actual temperature of the cooling chamber and the set temperature of the cooling chamber such as after completion of the defrosting operation so that the compressor 11 does not stop (thermo-off) until the state of the refrigeration cycle becomes stable. To be done.
  • the inspection mode is performed when the evaporation temperature of the non-azeotropic refrigerant converted from the set pressure is higher than the set temperature of the cooling chamber. Since the thermo-off does not occur, the stable state can be maintained to detect the leakage of the refrigerant.
  • FIG. 3 is a ph diagram showing the state in the inspection mode in the first embodiment of the present invention.
  • the refrigerant circuit 10 is controlled such that the condensation temperature, the degree of subcooling, and the low pressure are stabilized at predetermined values.
  • the non-azeotropic refrigerant compressed by the compressor 11 is condensed by the condenser 12, passes through the point A, and is further subcooled to the point B. Thereafter, the non-azeotropic refrigerant is decompressed by the expansion unit 13 and reaches point C. Then, it is evaporated by the evaporator 14 and sucked into the compressor 11.
  • the control device 50 performs an operation in which the condensation temperature, the degree of subcooling, and the low pressure become the target values until the pressure and temperature of each part become stable.
  • the condensation temperature is 45 ° C., the degree of supercooling 5 K, and the low pressure 0.3 MPa.
  • the inspection condition is a condition at which the condensation temperature, the subcooling degree, and the low pressure become target values.
  • the condensation temperature is the temperature of the non-azeotropic refrigerant flowing to the condenser 12.
  • the condensation temperature is detected by the condensation temperature sensor 21.
  • the degree of subcooling is a degree of subcooling of the non-azeotropic refrigerant flowing to the inlet side of the expansion portion 13.
  • the degree of subcooling is obtained by subtracting the temperature before expansion detected by the expansion inlet temperature sensor 22 from the condensation temperature detected by the condensation temperature sensor 21.
  • the low pressure is the pressure of the non-azeotropic refrigerant flowing to the inlet side of the evaporator 14.
  • the low pressure is detected by the low pressure sensor 23.
  • the controller 50 controls the operating frequency of the compressor 11 and the fan (not shown) of the condenser 12 so that the low pressure in the inspection mode is higher than the low pressure in the cooling operation in the normal operation mode. Adjust the output etc.
  • the controller 50 controls the operating frequency of the compressor 11 and the output of the fan (not shown) of the condenser 12 so that the condensing temperature in the inspection mode is lower than the condensing temperature in the cooling operation in the normal operation mode. Etc. are adjusted.
  • the control device 50 makes the number of rotations of the fan blowing to the condenser 12 higher in the inspection mode than in the normal operation mode.
  • the condensation temperature of the condenser 12 is lowered, and the degree of subcooling is increased accordingly, so the density of the liquid refrigerant is increased. Therefore, the amount of liquid refrigerant circulating in the refrigerant circuit 10 increases, and the amount of surplus refrigerant remaining in the accumulator 15 decreases.
  • control device 50 makes the rotation speed of the compressor 11 higher in the inspection mode than in the normal operation mode. Thereby, the amount of the refrigerant circulating to the refrigerant circuit 10 is increased. Furthermore, the control device 50 makes the opening degree of the expansion portion 13 larger in the inspection mode than in the normal operation mode. Thereby, the amount of the refrigerant circulating to the refrigerant circuit 10 is increased. As described above, the excess refrigerant is reduced from the accumulator 15 and the non-azeotropic refrigerant circulating in the refrigerant circuit 10 is increased to keep the composition ratio of the non-azeotropic refrigerant circulating in the refrigerant circuit 10 uniform. As the inspection condition, instead of the condensation temperature, the high pressure may be a target value.
  • the controller 50 is based on the saturation temperature theoretical value determined from the inlet pressure of the non-azeotropic refrigerant flowing to the inlet side of the evaporator 14 and the inlet temperature of the non-azeotropic refrigerant flowing to the inlet side of the evaporator 14. Determine the azeotropic refrigerant leakage. Specifically, when the subtraction value obtained by subtracting the theoretical saturation temperature value from the inlet temperature exceeds the subtraction threshold value, the control device 50 determines that the non-azeotropic refrigerant has leaked.
  • the subtraction threshold is, for example, 1.5K. In addition, when the control device 50 continuously detects that the subtraction value exceeds the subtraction threshold for five minutes, it may determine that the refrigerant leaks and output an alarm.
  • FIG. 4 is a table showing temperatures of respective portions associated with a change in the composition of R407C which is a non-azeotropic refrigerant in the first embodiment of the present invention.
  • the temperature at point A in FIG. 3 is 45 ° C.
  • the temperature at point B is 40 ° C.
  • the temperature at point C is -15.9 ° C.
  • -15.9 ° C. is a theoretical value of the low-pressure pressure saturation temperature when it is assumed that the composition ratio is a set ratio.
  • the saturation temperature increases when the low pressure is a constant value.
  • the control device 50 determines that the non-azeotropic refrigerant has leaked when a 10% leak is assumed to be 1.7 K where the temperature difference exceeds the subtraction threshold 1.5 K.
  • the refrigerant circulating in the refrigerant circuit 10 has a high ratio of R32 and R125, when the non-azeotropic refrigerant leaks in the refrigerant circuit 10, R32 and R125 leak more than R134a. For this reason, as the refrigerant leakage progresses, the composition ratio changes so that the ratio of R134a in all the refrigerant gradually increases. R134a has a higher boiling point than R32 and R125. Therefore, as the composition ratio changes, the saturation temperature increases when the low pressure is a constant value. In the first embodiment, the leakage of the refrigerant is detected using this phenomenon.
  • FIG. 5 is a flowchart showing an operation of the refrigeration air conditioning system 100 according to Embodiment 1 of the present invention.
  • the control device 50 first determines whether the defrosting operation has ended (step ST1). If the defrosting operation has not ended (No in step ST1), the process returns to step ST1.
  • the control device 50 determines whether the thermo stop is not performed in order to confirm whether the stable period necessary for the inspection is secured (step ST2). .
  • the process proceeds to step ST3.
  • step ST3 target values of the condensation temperature, the degree of subcooling, and the low pressure are set.
  • the control device 50 determines whether or not the condensation temperature, the degree of subcooling, and the low pressure have become target values (step ST4).
  • the control device 50 performs an operation in which the condensation temperature, the degree of subcooling, and the low pressure become the target values until the pressure and temperature of each part become stable. If the condensation temperature, the subcooling degree, and the low pressure are not the target values (No in step ST4), the process returns to step ST4.
  • the controller 50 determines whether the subtraction value obtained by subtracting the theoretical saturation temperature value from the inlet temperature exceeds the subtraction threshold. It determines (step ST5).
  • step ST5 If the subtraction value exceeds the subtraction threshold (Yes in step ST5), the control device 50 determines that the non-azeotropic refrigerant has leaked. On the other hand, if the subtraction value is equal to or less than the subtraction threshold (No in step ST5), the control device 50 determines whether the thermo stop has occurred (step ST6). When the thermo stop is not performed (No in step ST6), the determination is repeated (steps ST4 to ST6). If the thermo stop has occurred due to the cooling in the inspection mode (Yes in step ST6), the control device 50 determines that the non-azeotropic refrigerant has not leaked.
  • the refrigerant circuit 10 is operated under the inspection condition to keep the low pressure of the refrigerant circuit 10 at the set pressure, and the state of the refrigerant circuit 10 is stabilized. For this reason, regardless of the pipe length of the refrigerant circuit 10, the low pressure is maintained at the set pressure, so the state of the refrigerant circuit 10 can be stabilized regardless of the pipe length of the refrigerant circuit 10. Therefore, the leakage of the refrigerant can be accurately detected regardless of the pipe length of the refrigerant circuit 10.
  • the condensation temperature of the non-azeotropic refrigerant is set to be lower than that in the normal operation mode.
  • the amount of refrigerant in the circuit necessary for the operation of the refrigeration air conditioning apparatus 100 changes depending on the ambient temperature accompanying the seasonal fluctuation. Therefore, the refrigerant
  • coolant amount is enclosed by the refrigerating air-conditioning apparatus 100. As shown in FIG. For this reason, the surplus refrigerant remains in the pressure vessel such as the accumulator 15 provided in the refrigerant circuit 10 for most of the period of one year.
  • the conventional refrigerant shortage detection method compares the theoretical inlet temperature value assuming that the refrigerant is sufficiently present in the refrigeration circuit with the inlet temperature actually measured in a state where the surplus refrigerant is stored in the accumulator or the like. Do. However, even if the refrigerant in the refrigerant circuit leaks, the refrigerant stored in the accumulator flows out into the refrigerant circuit, and the amount of refrigerant circulating in the refrigerant circuit is the excess refrigerant stored in the accumulator. It will not change almost until there is no That is, the inlet temperature to be measured does not change until the amount of the refrigerant larger than the excess refrigerant leaks. Therefore, it is difficult to detect the refrigerant leakage while the amount of leakage is small.
  • the condensation temperature of the non-azeotropic refrigerant in the inspection mode, is set to be lower than that in the normal operation mode. As the condensation temperature decreases, the degree of subcooling increases accordingly, and the density of the liquid refrigerant increases. Therefore, the amount of liquid refrigerant circulating in the refrigerant circuit 10 increases, and the amount of surplus refrigerant remaining in the accumulator 15 decreases. As described above, since the inspection is performed in a state where the amount of surplus refrigerant is small, the composition of the non-azeotropic refrigerant flowing in the refrigerant circuit 10 changes only when a small amount of the non-azeotropic refrigerant leaks.
  • the leakage of the non-azeotropic refrigerant can be detected from the stage where the amount of the non-azeotropic refrigerant leaking is small.
  • the amount of non-azeotropic refrigerant stored in the accumulator 15 is large, even if the non-azeotropic refrigerant circulating in the refrigerant circuit 10 leaks, the non-azeotropic refrigerant flows out from the accumulator 15 into the refrigerant circuit 10 Therefore, the state of the circulating non-azeotropic refrigerant does not change.
  • the composition of the non-azeotropic refrigerant flowing in the refrigerant circuit 10 is only when a small amount of the non-azeotropic refrigerant leaks. Change. Therefore, the leakage of the non-azeotropic refrigerant can be detected from the stage where the amount of refrigerant leakage is small. Thereby, even if it is the frozen air conditioner 100 using the fluorocarbon refrigerant
  • the low pressure temperature sensor is the evaporation inlet temperature sensor 24 that detects the temperature of the refrigerant flowing into the evaporator 14. Since the non-azeotropic refrigerant has a temperature gradient, the detection accuracy of the refrigerant leakage is improved by performing the determination of the refrigerant leakage using the temperature of the non-azeotropic refrigerant flowing into the evaporator 14. The evaporator 14 also cools the cooling chamber. Thus, by stabilizing the temperature of the room in which the evaporator 14 is installed, the detection accuracy of the refrigerant leakage is enhanced.
  • the refrigerant storage amount in the inspection mode is constant regardless of the seasonal fluctuation. For this reason, it is possible to detect the leakage of the non-azeotropic refrigerant from the stage where the amount of leakage of the refrigerant is small, without being affected by the change of the surplus refrigerant amount accompanying the seasonal fluctuation.
  • the theoretical inlet temperature of the evaporator of the theoretical refrigeration cycle which is determined by the heat load when it is assumed that the refrigerant is sufficiently present in the refrigerant circuit, and the inlet temperature of the evaporator actually measured. It is judged that the refrigerant is insufficient based on the difference of The change in evaporator inlet temperature is due to the pressure drop in the refrigeration cycle associated with refrigerant leakage. That is, when a change in the inlet temperature of the evaporator is detected, the cooling capacity of the refrigeration air conditioning system is insufficient due to the shortage of the refrigerant. For this reason, when a reduction in cooling capacity such as a refrigerator and an objective air conditioning application is directly linked to the quality of a stored item, the stored item may be deteriorated and broken.
  • the non-azeotropic refrigerant in order to detect the leakage of the non-azeotropic refrigerant from the stage where the leakage amount of the refrigerant is small, the non-azeotropic refrigerant is detected only by performing the operation with constant conditions for a short time.
  • the refrigerant can be detected at a timing that is necessary for the operation of the refrigeration cycle, such as a pull-down operation after the end of defrosting, and does not affect the quality of stored items. For this reason, it does not lead to the change of the inlet temperature leading to deterioration and failure of the quality of stored goods.
  • the state of the theoretical refrigeration cycle changes due to the effect of pressure loss occurring in the on-site piping.
  • the conventional refrigeration air conditioning system uses a method of computing a theoretical refrigeration cycle based on heat load, assuming that a necessary amount of refrigerant is present in a refrigeration circuit. For this reason, the theoretical refrigeration cycle determined by calculation and the theoretical refrigeration cycle in actual operation do not match, and the refrigerant leakage can not be detected correctly.
  • the operation under constant conditions is performed.
  • the refrigerant leaks without being affected by the on-site construction conditions such as changes in high pressure and low pressure due to pressure loss in the on-site piping and changes in the degree of supercooling due to the effect of rising pipe length. It can be detected accurately.
  • Embodiment 1 exemplifies the case where the inspection mode is executed under specific conditions that allow continuous operation, such as after completion of the defrosting operation, the in-device temperature is the target in-device temperature. However, control may be performed to continue the operation without stopping the thermo. This ensures that the inspection mode is performed. As described above, in the first embodiment, in the inspection mode, even if the temperature of the air to be cooled reaches the temperature threshold, control may be performed to continue the operation of the refrigerant circuit 10.
  • the control device 50 may acquire the inlet temperature a plurality of times at fixed time intervals. In this case, the control device 50 determines that the non-azeotropic refrigerant is leaking when, for example, the plurality of measured values are averaged over a 30-second interval with time and the average value satisfies the determination condition ten consecutive times. Do.
  • FIG. 6 is a table showing boiling points and composition ratios of refrigerants constituting the non-azeotropic refrigerants R422A, R422D and R417A according to the second embodiment of the present invention.
  • the second embodiment is different from the first embodiment in that leakage can be detected in a plurality of refrigerants.
  • the same parts as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. The differences from the first embodiment will be mainly described.
  • the configuration of the refrigerant circuit 10 is the same as that of the first embodiment.
  • the used refrigerant can be selected by the control device 50, and all of R422A, R422D, and R417A can be adopted.
  • the composition ratio of R422A is 85.1% for R125, 11.5% for R134a, and 3.4% for R600a.
  • the composition ratio of R422D is 65.1% for R125, 31.5% for R134a, and 3.4% for R600a.
  • the compositional ratio of R417A is 46.6% for R125, 50.0% for R134a, and 3.4% for R600.
  • R125 The boiling point of R125 is -48.1 ° C
  • R134a is -26.1 ° C
  • R600a is -11.7 ° C
  • R600 is -0.55 ° C. That is, R134a, R600a and R600 have boiling points higher than R125.
  • R125 is referred to as a first refrigerant group
  • R134a, R600a, and R600 are referred to as a second refrigerant group.
  • the composition ratio of the second refrigerant group is 30% or more, and in R422A, the composition ratio of the second refrigerant group is less than 30%.
  • R407C illustrated in the first embodiment has R32 and R125 as the first refrigerant group, and R134a having a boiling point higher than R32 and R125 as the second refrigerant group, the composition ratio of the second refrigerant group is 30. % Or more.
  • the control device 50 classifies and sets the type of non-azeotropic refrigerant into the first refrigerant group and the second refrigerant group having a boiling point higher than that of the first refrigerant group.
  • the subtraction threshold is set based on the type of non-azeotropic refrigerant.
  • the subtraction threshold is set based on the composition ratio of the second refrigerant group.
  • the subtraction threshold may be associated with a table stored in advance, or may be set individually.
  • FIG. 7 is a table showing the temperature of each part according to the composition change of R422A in the second embodiment of the present invention.
  • the temperature at point A in FIG. 3 is 45 ° C.
  • the temperature at point B is 40 ° C.
  • the temperature at point C is ⁇ 20.3 ° C.
  • -20.3 ° C. is a theoretical value of saturation temperature of low pressure when it is assumed that the composition ratio is appropriate.
  • the saturation temperature increases when the low pressure is a constant value.
  • the temperature change at point C is 0.5 K when it leaks 15%.
  • FIG. 8 is a table showing the temperature of each part according to the change in composition of R422D in the second embodiment of the present invention.
  • the temperature at point A in FIG. 3 is 45 ° C.
  • the temperature at point B is 40 ° C.
  • the temperature at point C is -15.6 ° C.
  • -15.6 ° C. is a theoretical value of saturation temperature of low pressure when it is assumed that the composition ratio is appropriate.
  • the saturation temperature rises when the low pressure is a constant value.
  • the temperature change at point C is 1.2 K when it leaks 15%.
  • FIG. 9 is a table showing the temperatures of respective portions according to the composition change of R417A in the second embodiment of the present invention.
  • the temperature at point A in FIG. 3 is 45 ° C.
  • the temperature at point B is 40 ° C.
  • the temperature at point C is ⁇ 11.0 ° C.
  • ⁇ 11.0 ° C. is a theoretical value of the saturation temperature of the low pressure when it is assumed that the composition ratio is appropriate.
  • the saturation temperature when the low pressure is a constant value rises.
  • the temperature change at point C is 1.2 K when 10% leaks and 1.9 K when 15% leaks.
  • the subtraction threshold is set based on the composition ratio of the second refrigerant group. For example, in R422A, as shown in FIG. 7, the subtraction threshold value is set to 0.5 K, which is detected when the refrigerant leaks 15%. Further, in R422D, as shown in FIG. 8, the subtraction threshold is set to 1.0 K, so that detection is performed when the refrigerant leaks 10%. In R 417 A, as shown in FIG.
  • the subtraction threshold value is set to 1.0 K, so that it is detected when the refrigerant leaks 15%.
  • the leak threshold of the plurality of refrigerants can be detected by changing the subtraction threshold based on the composition ratio of the second refrigerant group.
  • Control device 50 may execute an inspection mode different from the above-described inspection mode.
  • the composition ratio of the second refrigerant group is less than 30% as in R422A
  • the temperature change at point C is as small as 0.5 K even if the refrigerant leaks 15%. Therefore, it is necessary to reduce the subtraction threshold value to 0.5 K, but in this case, there is a possibility that the leakage may be erroneously detected due to the measurement variation.
  • the subtraction threshold value is 1.0 K, the leakage can not be detected until the temperature difference leaks to nearly 30% at which the temperature difference is 1.2 K. Therefore, depending on the type of refrigerant, a plurality of inspection modes may be used properly.
  • control device 50 selects the inlet temperature of the evaporator 14 as in the conventional case.
  • a detection mode is executed to determine the presence or absence of leakage based on the difference from the theoretical value.
  • control device 50 executes the inspection mode of the first embodiment when a refrigerant having a composition ratio of the second refrigerant group higher than that of the first refrigerant group is selected. Do.
  • leakage detection can be performed according to the type of refrigerant, which contributes to a reduction in the amount of refrigerant leakage.
  • FIG. 10 is a circuit diagram showing a refrigeration air conditioning system 200 according to Embodiment 3 of the present invention.
  • the third embodiment is different from the first embodiment in that the liquid reservoir 33 is provided.
  • the same parts as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. The differences from the first embodiment will be mainly described.
  • the liquid reservoir 33 is connected between the condenser 12 and the expansion section 13 and stores excess refrigerant.
  • the excess refrigerant is stored inside the liquid reservoir 33, and the liquid phase refrigerant flows out from the outlet of the liquid reservoir 33.
  • the control device 50 performs the operation of moving the surplus refrigerant out of the non-azeotropic refrigerant flowing in the refrigerant circuit 10 to the accumulator 15 which is the pressure vessel on the low pressure side before the execution of the inspection mode. After, execute the inspection mode.
  • the leakage of the refrigerant can be detected.
  • leakage detection due to composition change can be performed, and a broader range of product groups can be used. Leakage of refrigerant can be detected.
  • leakage may be detected in a plurality of refrigerants.

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  • Physics & Mathematics (AREA)
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Abstract

A refrigeration and air conditioning device comprises: a refrigerant circuit in which a compressor, a condenser, an expansion unit, and an evaporator are connected by piping and in which a non-azeotropic refrigerant circulates; a low pressure temperature sensor that detects the temperature of the non-azeotropic refrigerant at low pressure in the refrigerant circuit; and a control device that has an inspection mode to determine the presence of a non-azeotropic refrigerant leak using the temperature detected with the low pressure temperature sensor while operating the refrigerant circuit under inspection conditions that maintain the low pressure of the refrigerant circuit at a set pressure.

Description

冷凍空調装置及び制御装置Refrigerating air conditioner and control device
　本発明は、冷媒回路に封入される冷媒の漏洩の有無を判定する制御装置を備える冷凍空調装置及び制御装置に関する。 BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a refrigeration air conditioning apparatus and a control apparatus provided with a control apparatus that determines the presence or absence of leakage of a refrigerant sealed in a refrigerant circuit.
　従来、冷媒の漏洩の有無を判定する制御装置を備える冷凍空調装置が知られている。特許文献１には、冷媒の漏洩等によって発生する冷凍回路の冷媒不足の検出方法が開示されている。特許文献１は、冷凍回路中に冷媒が充分に存在すると仮定したときに熱負荷によって求められる蒸発器の入口温度理論値と、実際に計測された蒸発器の入口温度との差が所定の値以上である状態が一定期間継続したときに、冷媒が不足していると判断する。 Conventionally, a refrigerating air-conditioning apparatus provided with a control device that determines the presence or absence of refrigerant leakage is known. Patent Document 1 discloses a method of detecting a shortage of refrigerant in a refrigeration circuit which is generated due to the leakage of the refrigerant or the like. In Patent Document 1, it is assumed that the difference between the theoretical inlet temperature of the evaporator, which is determined by the heat load when it is assumed that the refrigerant is sufficiently present in the refrigeration circuit, and the inlet temperature of the evaporator actually measured When the above state continues for a fixed period, it is determined that the refrigerant is insufficient.
特開平５－９９５４２号公報JP-A-5-99542
　このように、特許文献１に開示された冷媒不足検出方法は、圧力低下による状態量の変化を用いて冷媒漏洩を検出している。冷媒回路の配管長等が変化した場合、圧力低下を判定する閾値も変わるため、冷媒の漏洩を精度良く検出することが困難である。 As described above, the refrigerant shortage detection method disclosed in Patent Document 1 detects refrigerant leakage using a change in state quantity due to a pressure drop. When the pipe length or the like of the refrigerant circuit changes, the threshold value for determining the pressure drop also changes, so it is difficult to detect the refrigerant leakage with high accuracy.
　本発明は、上記のような課題を解決するためになされたもので、冷媒回路の配管長に依存することなく、冷媒の漏洩を検出することができる冷凍空調装置及び制御装置を提供するものである。 The present invention has been made to solve the above problems, and provides a refrigeration air conditioner and a control device capable of detecting the leakage of refrigerant without depending on the pipe length of the refrigerant circuit. is there.
　本発明に係る冷凍空調装置は、圧縮機、凝縮器、膨張部及び蒸発器が配管により接続され、非共沸冷媒が循環する冷媒回路と、冷媒回路の低圧の非共沸冷媒の温度を検出する低圧温度センサと、冷媒回路の低圧を設定圧力に保つ点検条件で冷媒回路を動作させて、低圧温度センサが検出した温度を用いて非共沸冷媒の漏洩の有無を判定する点検モードを有する制御装置と、を備える。 In the refrigeration air conditioner according to the present invention, the compressor, the condenser, the expansion unit, and the evaporator are connected by piping, and the temperature of the low-pressure non-azeotropic refrigerant in the refrigerant circuit and the refrigerant circuit in which the non-azeotropic refrigerant circulates is detected The refrigerant circuit is operated under an inspection condition for maintaining the low pressure of the refrigerant circuit at the set pressure, and the inspection mode is used to determine the presence or absence of non-azeotropic refrigerant leakage using the temperature detected by the low pressure temperature sensor. And a controller.
　本発明によれば、冷媒回路の低圧を設定圧力に保つ点検条件で冷媒回路を動作させて、冷媒回路の状態を安定化させる。このため、冷媒回路の配管長に依らず、低圧が設定圧力に保たれるため、冷媒回路の配管長に依らず、冷媒回路の状態を安定化させることができる。従って、冷媒回路の配管長に依らずに冷媒の漏洩を精度良く検出することができる。 According to the present invention, the refrigerant circuit is operated under the inspection condition for keeping the low pressure of the refrigerant circuit at the set pressure, and the state of the refrigerant circuit is stabilized. Therefore, the low pressure is maintained at the set pressure regardless of the pipe length of the refrigerant circuit, so the state of the refrigerant circuit can be stabilized regardless of the pipe length of the refrigerant circuit. Therefore, the leakage of the refrigerant can be accurately detected regardless of the pipe length of the refrigerant circuit.
本発明の実施の形態１に係る冷凍空調装置１００を示す回路図である。BRIEF DESCRIPTION OF THE DRAWINGS It is a circuit diagram which shows the refrigerating air conditioner 100 which concerns on Embodiment 1 of this invention. 本発明の実施の形態１における非共沸冷媒であるＲ４０７Ｃを構成する冷媒の沸点及び組成比率を示す表である。It is a table which shows the boiling point and composition ratio of a refrigerant which constitutes R407C which is a non-azeotropic refrigerant in Embodiment 1 of the present invention. 本発明の実施の形態１における点検モード時の状態を示すｐ－ｈ線図である。FIG. 7 is a ph diagram showing the state in the inspection mode in the first embodiment of the present invention. 本発明の実施の形態１における非共沸冷媒であるＲ４０７Ｃの組成変化に伴う各部温度を示す表である。It is a table | surface which shows each part temperature accompanying a composition change of R407C which is a non-azeotropic refrigerant | coolant in Embodiment 1 of this invention. 本発明の実施の形態１に係る冷凍空調装置１００の動作を示すフローチャートである。It is a flowchart which shows operation | movement of the refrigerating air conditioner 100 which concerns on Embodiment 1 of this invention. 本発明の実施の形態２における非共沸冷媒であるＲ４２２Ａ、Ｒ４２２Ｄ及びＲ４１７Ａを構成する冷媒の沸点及び組成比率を示す表である。It is a table which shows the boiling point and composition ratio of a refrigerant which constitutes R422A, R422D, and R417A which are non-azeotropic refrigerants in Embodiment 2 of the present invention. 本発明の実施の形態２におけるＲ４２２Ａの組成変化に伴う各部温度を示す表である。It is a table | surface which shows each part temperature accompanying the composition change of R422A in Embodiment 2 of this invention. 本発明の実施の形態２におけるＲ４２２Ｄの組成変化に伴う各部温度を示す表である。It is a table | surface which shows each part temperature accompanying the composition change of R422D in Embodiment 2 of this invention. 本発明の実施の形態２におけるＲ４１７Ａの組成変化に伴う各部温度を示す表である。It is a table | surface which shows each part temperature accompanying the composition change of R417A in Embodiment 2 of this invention. 本発明の実施の形態３に係る冷凍空調装置２００を示す回路図である。It is a circuit diagram which shows the refrigerating air conditioner 200 which concerns on Embodiment 3 of this invention.
実施の形態１．
　以下、本発明に係る冷凍空調装置及び制御装置の実施の形態について、図面を参照しながら説明する。図１は、本発明の実施の形態１に係る冷凍空調装置１００を示す回路図である。この図１に基づいて、冷凍空調装置１００について説明する。図１に示すように、冷凍空調装置１００は、冷却庫のような冷却対象を冷却する装置であり、冷媒回路１０と、凝縮温度センサ２１と、膨張入口温度センサ２２と、低圧圧力センサ２３と、蒸発入口温度センサ２４と、制御装置５０とを備えている。冷媒回路１０は、圧縮機１１、凝縮器１２、膨張部１３、蒸発器１４及びアキュムレータ１５が配管により接続され、沸点が異なる冷媒が混合された非共沸冷媒が循環する。 Embodiment 1
Hereinafter, an embodiment of a refrigeration air conditioner and a control device according to the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram showing a refrigerating and air-conditioning apparatus 100 according to Embodiment 1 of the present invention. The refrigeration air conditioner 100 will be described based on FIG. As shown in FIG. 1, the refrigeration air conditioning system 100 is an apparatus for cooling a cooling object such as a refrigerator, and includes a refrigerant circuit 10, a condensation temperature sensor 21, an expansion inlet temperature sensor 22, and a low pressure pressure sensor 23. , And an evaporation inlet temperature sensor 24 and a controller 50. In the refrigerant circuit 10, the compressor 11, the condenser 12, the expansion unit 13, the evaporator 14, and the accumulator 15 are connected by piping, and a non-azeotropic refrigerant in which refrigerants having different boiling points are mixed circulates.
　圧縮機１１は、低温低圧の状態の非共沸冷媒を吸入及び圧縮して高温高圧の状態の非共沸冷媒を吐出する。圧縮機１１は、例えば容量を制御することができるインバータ圧縮機からなる。凝縮器１２は、例えば室外空気と非共沸冷媒との間で熱交換させる。膨張部１３は、非共沸冷媒を減圧して膨張する減圧弁又は膨張弁である。膨張部１３は、例えば開度が調整される電子式膨張弁からなる。蒸発器１４は、例えば冷却室の冷却を行い、冷却室の空気と非共沸冷媒との間で熱交換させる。アキュムレータ１５は、ガス冷媒と液冷媒とを分離し、冷媒回路１０に流れる非共沸冷媒のうち、余剰となった余剰冷媒を貯留する。なお、冷凍空調装置１００は、冷媒回路１０に流れる非共沸冷媒の流れ方向を切り替える流路切替部を備えていてもよい。この場合、冷凍空調装置１００は、冷却運転及び加熱運転のいずれも実行することができる。 The compressor 11 sucks and compresses the non-azeotropic refrigerant in the low temperature and low pressure state and discharges the non-azeotropic refrigerant in the high temperature and high pressure state. The compressor 11 is, for example, an inverter compressor capable of controlling the capacity. The condenser 12 exchanges heat, for example, between outdoor air and a non-azeotropic refrigerant. The expansion unit 13 is a pressure reducing valve or an expansion valve that decompresses and expands a non-azeotropic refrigerant. The expansion portion 13 is, for example, an electronic expansion valve whose opening degree is adjusted. The evaporator 14 cools the cooling chamber, for example, to exchange heat between the air in the cooling chamber and the non-azeotropic refrigerant. The accumulator 15 separates the gas refrigerant and the liquid refrigerant, and stores the surplus refrigerant which has become surplus among the non-azeotropic refrigerant flowing in the refrigerant circuit 10. In addition, the refrigeration air conditioning apparatus 100 may include a flow path switching unit that switches the flow direction of the non-azeotropic refrigerant flowing in the refrigerant circuit 10. In this case, the refrigeration air conditioning apparatus 100 can execute both the cooling operation and the heating operation.
　次に、冷凍空調装置１００の冷却運転について説明する。冷却運転において、圧縮機１１に吸入された冷媒は、圧縮機１１によって圧縮されて高温高圧のガス状態で吐出される。圧縮機１１から吐出された高温高圧のガス状態の冷媒は、凝縮器１２に流入し、凝縮器１２において、室外空気と熱交換されて凝縮して液化する。凝縮された液状態の冷媒は、膨張部１３に流入し、膨張部１３において膨張及び減圧されて低温低圧の気液二相状態の冷媒となる。そして、気液二相状態の冷媒は、蒸発器１４に流入し、蒸発器１４において、冷却室の空気と熱交換されて蒸発してガス化する。このとき、冷却室が冷却される。蒸発した低温低圧のガス状態の冷媒は、圧縮機１１に吸入される。 Next, the cooling operation of the refrigeration air conditioner 100 will be described. In the cooling operation, the refrigerant drawn into the compressor 11 is compressed by the compressor 11 and discharged in a high-temperature high-pressure gas state. The high-temperature high-pressure gas refrigerant discharged from the compressor 11 flows into the condenser 12, and in the condenser 12, it exchanges heat with outdoor air, condenses, and liquefies. The condensed refrigerant in the liquid state flows into the expansion unit 13 and is expanded and reduced in pressure in the expansion unit 13 to become a low-temperature low-pressure gas-liquid two-phase refrigerant. Then, the refrigerant in the gas-liquid two-phase state flows into the evaporator 14, and in the evaporator 14, it exchanges heat with the air in the cooling chamber to evaporate and gasify. At this time, the cooling chamber is cooled. The evaporated low-temperature low-pressure gas refrigerant is drawn into the compressor 11.
　凝縮温度センサ２１は、凝縮器１２に流れる非共沸冷媒の凝縮温度を検出する。膨張入口温度センサ２２は、膨張部１３の入口側に設けられ、膨張部１３の入口側に流れる非共沸冷媒の膨張前温度を検出する。低圧圧力センサ２３は、蒸発器１４の入口側に設けられ、蒸発器１４の入口側に流れる非共沸冷媒の低圧圧力を検出する。蒸発入口温度センサ２４は、蒸発器１４の入口側に設けられ、蒸発器１４の入口側に流れる非共沸冷媒の入口温度を検出する。なお、蒸発入口温度センサ２４は、低圧温度センサに相当する。 The condensation temperature sensor 21 detects the condensation temperature of the non-azeotropic refrigerant flowing to the condenser 12. The expansion inlet temperature sensor 22 is provided on the inlet side of the expansion portion 13 and detects the temperature before expansion of the non-azeotropic refrigerant flowing to the inlet side of the expansion portion 13. The low pressure sensor 23 is provided on the inlet side of the evaporator 14 and detects the low pressure of the non-azeotropic refrigerant flowing to the inlet side of the evaporator 14. The evaporation inlet temperature sensor 24 is provided on the inlet side of the evaporator 14 and detects the inlet temperature of the non-azeotropic refrigerant flowing to the inlet side of the evaporator 14. The evaporation inlet temperature sensor 24 corresponds to a low pressure temperature sensor.
　図２は、本発明の実施の形態１における非共沸冷媒であるＲ４０７Ｃを構成する冷媒の沸点及び組成比率を示す表である。本実施の形態１において、冷媒回路１０に封入されている非共沸冷媒は、Ｒ４０７Ｃである。図２に示すように、Ｒ４０７Ｃは、Ｒ３２とＲ１２５とＲ１３４ａとが混合されている。沸点は、Ｒ３２が－５１．７℃であり、Ｒ１２５が－４８．１℃であり、Ｒ１３４ａが－２６．１℃である。即ち、Ｒ４０７Ｃを構成する冷媒のなかで、Ｒ１３４ａの沸点が最も高い。 FIG. 2 is a table showing the boiling point and the composition ratio of the refrigerant that constitutes R407C, which is the non-azeotropic refrigerant in the first embodiment of the present invention. In the first embodiment, the non-azeotropic refrigerant sealed in the refrigerant circuit 10 is R407C. As shown in FIG. 2, R407C is a mixture of R32, R125 and R134a. The boiling points are as follows: R32 is -51.7 ° C, R125 is -48.1 ° C, and R134a is -26.1 ° C. That is, among the refrigerants constituting R407C, the boiling point of R134a is the highest.
　また、組成比率は、Ｒ３２が２３％であり、Ｒ１２５が２５％であり、Ｒ１３４ａが５２％である。ここで、アキュムレータ１５に貯留する非共沸冷媒は、主に、ガス冷媒と分離された液冷媒であり、アキュムレータ１５に貯留する冷媒は、沸点が高いためにガス化し難いＲ１３４ａの比率が高い。このため、冷媒回路１０内を循環する冷媒は、Ｒ３２及びＲ１２５の比率が高い。 In addition, the composition ratio is 23% for R32, 25% for R125, and 52% for R134a. Here, the non-azeotropic refrigerant stored in the accumulator 15 is mainly a liquid refrigerant separated from the gas refrigerant, and the refrigerant stored in the accumulator 15 has a high ratio of R134a which is difficult to be gasified because the boiling point is high. For this reason, the refrigerant circulating in the refrigerant circuit 10 has a high ratio of R32 and R125.
　非共沸冷媒の冷媒密度は、季節変動又は冷却負荷変動によって高圧側圧力及び低圧側圧力が変化することに伴って変化する。高圧側圧力とは、圧縮機１１で圧縮された高圧の冷媒の圧力をいい、低圧側圧力とは、膨張部１３で膨張した低圧の冷媒の圧力をいう。このため、冷媒回路１０内に必要な冷媒量も変化する。従って、冷凍空調装置１００が現地に据え付けられる際、いかなる状況においても冷媒不足による能力損失及び過熱運転等が生じないように、必要な冷媒量の変化を見越した最大必要冷媒量以上の冷媒が封入される。このため、アキュムレータ１５には、必要冷媒量の変化によって生じた余剰冷媒が貯留する。 The refrigerant density of the non-azeotropic refrigerant changes as the high pressure side pressure and the low pressure side pressure change due to seasonal fluctuation or cooling load fluctuation. The high pressure side pressure refers to the pressure of the high pressure refrigerant compressed by the compressor 11, and the low pressure side pressure refers to the pressure of the low pressure refrigerant expanded in the expansion unit 13. Therefore, the amount of refrigerant required in the refrigerant circuit 10 also changes. Therefore, when the refrigeration air conditioning apparatus 100 is installed on the site, the refrigerant having the amount of the refrigerant required above the maximum amount of refrigerant in consideration of the change in the amount of refrigerant necessary is enclosed so that the capacity loss due to the refrigerant shortage and the overheating operation do not occur under any circumstances. Be done. Therefore, surplus refrigerant generated due to the change of the required refrigerant amount is stored in the accumulator 15.
　制御装置５０は、各部の圧力及び温度の計測値と、各種設定値とに基づいて冷凍空調装置１００の制御を行う。制御装置５０は、凝縮温度センサ２１、膨張入口温度センサ２２、低圧圧力センサ２３及び蒸発入口温度センサ２４から取得した圧力及び温度に基づいて、冷凍空調装置１００の運転状態を把握する。制御装置５０は、凝縮器１２に吸い込まれる室外空気の温度、凝縮器１２の冷却風量、冷却負荷の大きさ及び圧縮機１１の消費電力によって、高圧圧力を調整する。また、制御装置５０は、圧縮機１１の運転周波数、蒸発器１４の冷却風量及び膨張部１３の開度等によって低圧圧力を調整し、蒸発器１４出口の過熱度を設定過熱度に保つ。 The control device 50 controls the refrigeration air conditioner 100 based on measured values of pressure and temperature of each part and various set values. The control device 50 grasps the operating state of the refrigeration air conditioner 100 based on the pressure and temperature acquired from the condensation temperature sensor 21, the expansion inlet temperature sensor 22, the low pressure sensor 23, and the evaporation inlet temperature sensor 24. The control device 50 adjusts the high pressure according to the temperature of the outdoor air sucked into the condenser 12, the amount of cooling air of the condenser 12, the size of the cooling load, and the power consumption of the compressor 11. Further, the control device 50 adjusts the low pressure according to the operating frequency of the compressor 11, the amount of cooling air of the evaporator 14, the opening degree of the expansion portion 13 and the like, and maintains the degree of superheat at the outlet of the evaporator 14 at the set degree of superheat.
　制御装置５０は、冷却室の空調を行う通常運転モードのほかに、冷媒漏洩を検出するための点検モードを有している。点検モードは、冷媒回路１０の低圧を設定圧力に保つ点検条件で冷媒回路１０を動作させて、非共沸冷媒の漏洩の有無を判定するモードである。制御装置５０は、比較的長時間の連続運転が可能となる条件下で、点検モードを実行する。例えば、冷凍サイクルの状態が安定するまで圧縮機１１が停止（サーモオフ）しないように、除霜運転終了後等、実際の冷却室の温度と冷却室の設定温度よりも高いとき等に点検モードが行われる。具体的には、設定圧力から換算される非共沸冷媒の蒸発温度が、冷却室の設定温度よりも高いときに点検モードが行われる。サーモオフにならないため、安定状態を保って冷媒の漏洩を検出することができる。 The controller 50 has an inspection mode for detecting a refrigerant leak, in addition to the normal operation mode for air conditioning the cooling chamber. The inspection mode is a mode in which the refrigerant circuit 10 is operated under inspection conditions for keeping the low pressure of the refrigerant circuit 10 at the set pressure, and the presence or absence of the non-azeotropic refrigerant leakage is determined. The controller 50 executes the inspection mode under the condition that continuous operation for a relatively long time is possible. For example, the inspection mode is performed when the temperature of the cooling chamber is higher than the actual temperature of the cooling chamber and the set temperature of the cooling chamber such as after completion of the defrosting operation so that the compressor 11 does not stop (thermo-off) until the state of the refrigeration cycle becomes stable. To be done. Specifically, the inspection mode is performed when the evaporation temperature of the non-azeotropic refrigerant converted from the set pressure is higher than the set temperature of the cooling chamber. Since the thermo-off does not occur, the stable state can be maintained to detect the leakage of the refrigerant.
　図３は、本発明の実施の形態１における点検モード時の状態を示すｐ－ｈ線図である。点検モード時には、凝縮温度と過冷却度と低圧圧力とが所定値で安定するように冷媒回路１０が制御される。図３に示すように、圧縮機１１で圧縮された非共沸冷媒は、凝縮器１２によって凝縮して、Ａ点を通過し、更に過冷却されてＢ点に至る。その後、非共沸冷媒は、膨張部１３によって減圧して、Ｃ点に至る。そして、蒸発器１４によって蒸発して、圧縮機１１に吸入される。制御装置５０は、凝縮温度と過冷却度と低圧圧力とが目標値となる運転を、各部の圧力及び温度が安定するまで行う。図３においては、凝縮温度４５℃、過冷却度５Ｋ及び低圧圧力０．３ＭＰａである。 FIG. 3 is a ph diagram showing the state in the inspection mode in the first embodiment of the present invention. In the inspection mode, the refrigerant circuit 10 is controlled such that the condensation temperature, the degree of subcooling, and the low pressure are stabilized at predetermined values. As shown in FIG. 3, the non-azeotropic refrigerant compressed by the compressor 11 is condensed by the condenser 12, passes through the point A, and is further subcooled to the point B. Thereafter, the non-azeotropic refrigerant is decompressed by the expansion unit 13 and reaches point C. Then, it is evaporated by the evaporator 14 and sucked into the compressor 11. The control device 50 performs an operation in which the condensation temperature, the degree of subcooling, and the low pressure become the target values until the pressure and temperature of each part become stable. In FIG. 3, the condensation temperature is 45 ° C., the degree of supercooling 5 K, and the low pressure 0.3 MPa.
　より具体的には、点検条件は、凝縮温度と過冷却度と低圧圧力とが目標値となる条件である。ここで、凝縮温度は、凝縮器１２に流れる非共沸冷媒の温度である。凝縮温度は、凝縮温度センサ２１によって検出される。過冷却度は、膨張部１３の入口側に流れる非共沸冷媒の過冷却度である。過冷却度は、凝縮温度センサ２１によって検出された凝縮温度から、膨張入口温度センサ２２によって検出された膨張前温度を減算して求められる。低圧圧力は、蒸発器１４の入口側に流れる非共沸冷媒の圧力である。低圧圧力は、低圧圧力センサ２３によって検出される。 More specifically, the inspection condition is a condition at which the condensation temperature, the subcooling degree, and the low pressure become target values. Here, the condensation temperature is the temperature of the non-azeotropic refrigerant flowing to the condenser 12. The condensation temperature is detected by the condensation temperature sensor 21. The degree of subcooling is a degree of subcooling of the non-azeotropic refrigerant flowing to the inlet side of the expansion portion 13. The degree of subcooling is obtained by subtracting the temperature before expansion detected by the expansion inlet temperature sensor 22 from the condensation temperature detected by the condensation temperature sensor 21. The low pressure is the pressure of the non-azeotropic refrigerant flowing to the inlet side of the evaporator 14. The low pressure is detected by the low pressure sensor 23.
　ここで、点検モード時の低圧圧力が通常運転モード時の冷却運転の低圧圧力よりも高くなるように、制御装置５０は、圧縮機１１の運転周波数及び凝縮器１２のファン（図示せず）の出力等を調整している。また、点検モード時の凝縮温度が通常運転モード時の冷却運転の凝縮温度よりも低くなるように、制御装置５０は、圧縮機１１の運転周波数及び凝縮器１２のファン（図示せず）の出力等を調整している。具体的には、制御装置５０は、点検モード時に、凝縮器１２に送風するファンの回転数を、通常運転モード時よりも高くする。これにより、凝縮器１２の凝縮温度が低下して、その分過冷却度が増すため、液冷媒の密度が増加する。このため、冷媒回路１０内に循環する液冷媒の量が多くなり、アキュムレータ１５に残存する余剰冷媒が少なくなる。 Here, the controller 50 controls the operating frequency of the compressor 11 and the fan (not shown) of the condenser 12 so that the low pressure in the inspection mode is higher than the low pressure in the cooling operation in the normal operation mode. Adjust the output etc. In addition, the controller 50 controls the operating frequency of the compressor 11 and the output of the fan (not shown) of the condenser 12 so that the condensing temperature in the inspection mode is lower than the condensing temperature in the cooling operation in the normal operation mode. Etc. are adjusted. Specifically, the control device 50 makes the number of rotations of the fan blowing to the condenser 12 higher in the inspection mode than in the normal operation mode. As a result, the condensation temperature of the condenser 12 is lowered, and the degree of subcooling is increased accordingly, so the density of the liquid refrigerant is increased. Therefore, the amount of liquid refrigerant circulating in the refrigerant circuit 10 increases, and the amount of surplus refrigerant remaining in the accumulator 15 decreases.
　更に、制御装置５０は、点検モード時に、圧縮機１１の回転数を、通常運転モード時よりも高くする。これにより、冷媒回路１０に循環する冷媒の量を増加させる。更にまた、制御装置５０は、点検モード時に、膨張部１３の開度を、通常運転モード時よりも大きくする。これにより、冷媒回路１０に循環する冷媒の量を増加させる。このように、アキュムレータ１５内から余剰冷媒を減らし、冷媒回路１０内に循環する非共沸冷媒を多くして、冷媒回路１０内に循環する非共沸冷媒の組成比率を均等に保っている。なお、点検条件は、凝縮温度の代わりに、高圧圧力が目標値となるようにしてもよい。 Furthermore, the control device 50 makes the rotation speed of the compressor 11 higher in the inspection mode than in the normal operation mode. Thereby, the amount of the refrigerant circulating to the refrigerant circuit 10 is increased. Furthermore, the control device 50 makes the opening degree of the expansion portion 13 larger in the inspection mode than in the normal operation mode. Thereby, the amount of the refrigerant circulating to the refrigerant circuit 10 is increased. As described above, the excess refrigerant is reduced from the accumulator 15 and the non-azeotropic refrigerant circulating in the refrigerant circuit 10 is increased to keep the composition ratio of the non-azeotropic refrigerant circulating in the refrigerant circuit 10 uniform. As the inspection condition, instead of the condensation temperature, the high pressure may be a target value.
　制御装置５０は、蒸発器１４の入口側に流れる非共沸冷媒の入口圧力から求められる飽和温度理論値と、蒸発器１４の入口側に流れる非共沸冷媒の入口温度とに基づいて、非共沸冷媒の漏洩を判定する。具体的には、制御装置５０は、入口温度から飽和温度理論値を減算した減算値が減算閾値を超える場合、非共沸冷媒が漏洩したと判定する。減算閾値は、例えば１．５Ｋである。また、制御装置５０は、減算値が減算閾値を超えたことを、５分間連続して検出した場合に、冷媒の漏洩が発生したと判定して、警報を出力してもよい。 The controller 50 is based on the saturation temperature theoretical value determined from the inlet pressure of the non-azeotropic refrigerant flowing to the inlet side of the evaporator 14 and the inlet temperature of the non-azeotropic refrigerant flowing to the inlet side of the evaporator 14. Determine the azeotropic refrigerant leakage. Specifically, when the subtraction value obtained by subtracting the theoretical saturation temperature value from the inlet temperature exceeds the subtraction threshold value, the control device 50 determines that the non-azeotropic refrigerant has leaked. The subtraction threshold is, for example, 1.5K. In addition, when the control device 50 continuously detects that the subtraction value exceeds the subtraction threshold for five minutes, it may determine that the refrigerant leaks and output an alarm.
　図４は、本発明の実施の形態１における非共沸冷媒であるＲ４０７Ｃの組成変化に伴う各部温度を示す表である。図４に示すように、図３のＡ点の温度が４５℃であり、Ｂ点の温度が４０℃であり、Ｃ点の温度が－１５．９℃である。なお、－１５．９℃は、組成比率が設定されている比率である場合を想定したときの低圧圧力の飽和温度理論値である。図４に示すように、冷媒の漏洩が進行するに従って、低圧圧力を一定値としたときの飽和温度が上昇する。制御装置５０は、温度差が減算閾値１．５Ｋを超える１．７Ｋとなる１０％漏れ想定時に、非共沸冷媒が漏洩したと判定する。 FIG. 4 is a table showing temperatures of respective portions associated with a change in the composition of R407C which is a non-azeotropic refrigerant in the first embodiment of the present invention. As shown in FIG. 4, the temperature at point A in FIG. 3 is 45 ° C., the temperature at point B is 40 ° C., and the temperature at point C is -15.9 ° C. Note that -15.9 ° C. is a theoretical value of the low-pressure pressure saturation temperature when it is assumed that the composition ratio is a set ratio. As shown in FIG. 4, as the leakage of the refrigerant progresses, the saturation temperature increases when the low pressure is a constant value. The control device 50 determines that the non-azeotropic refrigerant has leaked when a 10% leak is assumed to be 1.7 K where the temperature difference exceeds the subtraction threshold 1.5 K.
　前述の如く、冷媒回路１０内を循環する冷媒は、Ｒ３２及びＲ１２５の比率が高いため、冷媒回路１０内で非共沸冷媒の漏洩が発生した場合、Ｒ３２及びＲ１２５がＲ１３４ａよりも多く漏れる。このため、冷媒の漏洩が進行するにつれて、全冷媒中におけるＲ１３４ａの比率が徐々に高くなるように組成比率が変化する。Ｒ１３４ａは、Ｒ３２及びＲ１２５に比べて沸点が高い。このため、組成比率の変化に伴って、低圧圧力を一定値としたときの飽和温度が上昇する。本実施の形態１では、この現象を利用して、冷媒の漏洩を検出する。 As described above, since the refrigerant circulating in the refrigerant circuit 10 has a high ratio of R32 and R125, when the non-azeotropic refrigerant leaks in the refrigerant circuit 10, R32 and R125 leak more than R134a. For this reason, as the refrigerant leakage progresses, the composition ratio changes so that the ratio of R134a in all the refrigerant gradually increases. R134a has a higher boiling point than R32 and R125. Therefore, as the composition ratio changes, the saturation temperature increases when the low pressure is a constant value. In the first embodiment, the leakage of the refrigerant is detected using this phenomenon.
　図５は、本発明の実施の形態１に係る冷凍空調装置１００の動作を示すフローチャートである。次に、冷凍空調装置１００の動作について説明する。図５に示すように、制御装置５０は、まず、除霜運転が終了したか否かを判定する（ステップＳＴ１）。除霜運転が終了していない場合（ステップＳＴ１のＮｏ）、ステップＳＴ１に戻る。除霜運転が終了している場合（ステップＳＴ１のＹｅｓ）、制御装置５０は、点検に必要な安定期間が確保されているかを確認するために、サーモ停止しない状態かを判定する（ステップＳＴ２）。サーモ停止する状態である場合（ステップＳＴ２のＮｏ）、ステップＳＴ２に戻る。サーモ停止しない状態である場合（ステップＳＴ２のＹｅｓ）、ステップＳＴ３に移行する。ステップＳＴ３において、凝縮温度、過冷却度及び低圧圧力の目標値が設定される。 FIG. 5 is a flowchart showing an operation of the refrigeration air conditioning system 100 according to Embodiment 1 of the present invention. Next, the operation of the refrigeration air conditioner 100 will be described. As shown in FIG. 5, the control device 50 first determines whether the defrosting operation has ended (step ST1). If the defrosting operation has not ended (No in step ST1), the process returns to step ST1. When the defrosting operation is completed (Yes in step ST1), the control device 50 determines whether the thermo stop is not performed in order to confirm whether the stable period necessary for the inspection is secured (step ST2). . When it is in the state which carries out a thermo stop (No of step ST2), it returns to step ST2. When it is in the state which does not stop the thermo (Yes in step ST2), the process proceeds to step ST3. In step ST3, target values of the condensation temperature, the degree of subcooling, and the low pressure are set.
　そして、制御装置５０は、凝縮温度と過冷却度と低圧圧力とが目標値となっているかを判定する（ステップＳＴ４）。制御装置５０は、凝縮温度と過冷却度と低圧圧力とが目標値となる運転を、各部の圧力及び温度が安定するまで行う。凝縮温度と過冷却度と低圧圧力とが目標値となっていない場合（ステップＳＴ４のＮｏ）、ステップＳＴ４に戻る。一方、凝縮温度と過冷却度と低圧圧力とが目標値となった場合（ステップＳＴ４のＹｅｓ）、制御装置５０は、入口温度から飽和温度理論値を減算した減算値が減算閾値を超えるかを判定する（ステップＳＴ５）。 Then, the control device 50 determines whether or not the condensation temperature, the degree of subcooling, and the low pressure have become target values (step ST4). The control device 50 performs an operation in which the condensation temperature, the degree of subcooling, and the low pressure become the target values until the pressure and temperature of each part become stable. If the condensation temperature, the subcooling degree, and the low pressure are not the target values (No in step ST4), the process returns to step ST4. On the other hand, when the condensing temperature, the degree of subcooling, and the low pressure become the target values (Yes in step ST4), the controller 50 determines whether the subtraction value obtained by subtracting the theoretical saturation temperature value from the inlet temperature exceeds the subtraction threshold. It determines (step ST5).
　減算値が減算閾値を超える場合（ステップＳＴ５のＹｅｓ）、制御装置５０は、非共沸冷媒が漏洩したと判定する。一方、減算値が減算閾値以下の場合（ステップＳＴ５のＮｏ）、制御装置５０が、サーモ停止しているかを判定する（ステップＳＴ６）。サーモ停止していない場合（ステップＳＴ６のＮｏ）、判定が繰り返される（ステップＳＴ４～ＳＴ６）。点検モードによる冷却により、サーモ停止している場合（ステップＳＴ６のＹｅｓ）、制御装置５０は、非共沸冷媒が漏洩していないと判定する。 If the subtraction value exceeds the subtraction threshold (Yes in step ST5), the control device 50 determines that the non-azeotropic refrigerant has leaked. On the other hand, if the subtraction value is equal to or less than the subtraction threshold (No in step ST5), the control device 50 determines whether the thermo stop has occurred (step ST6). When the thermo stop is not performed (No in step ST6), the determination is repeated (steps ST4 to ST6). If the thermo stop has occurred due to the cooling in the inspection mode (Yes in step ST6), the control device 50 determines that the non-azeotropic refrigerant has not leaked.
　本実施の形態１によれば、冷媒回路１０の低圧を設定圧力に保つ点検条件で冷媒回路１０を動作させて、冷媒回路１０の状態を安定化させる。このため、冷媒回路１０の配管長に依らず、低圧が設定圧力に保たれるため、冷媒回路１０の配管長に依らず、冷媒回路１０の状態を安定化させることができる。従って、冷媒回路１０の配管長に依らずに冷媒の漏洩を精度良く検出することができる。 According to the first embodiment, the refrigerant circuit 10 is operated under the inspection condition to keep the low pressure of the refrigerant circuit 10 at the set pressure, and the state of the refrigerant circuit 10 is stabilized. For this reason, regardless of the pipe length of the refrigerant circuit 10, the low pressure is maintained at the set pressure, so the state of the refrigerant circuit 10 can be stabilized regardless of the pipe length of the refrigerant circuit 10. Therefore, the leakage of the refrigerant can be accurately detected regardless of the pipe length of the refrigerant circuit 10.
　また、点検モード時は、通常運転モードと比較して、非共沸冷媒の凝縮温度が低くなるように設定される。ここで、冷凍空調装置１００の運転に必要な回路内の冷媒量は、季節変動に伴う周囲温度によって変化する。よって、冷凍空調装置１００には、最大の必要冷媒量を想定した冷媒量が封入されている。このため、一年間のうち大半の期間において、冷媒回路１０内に設けられたアキュムレータ１５等の圧力容器に余剰冷媒が滞留している。従来の冷媒不足検出方法は、冷凍回路中に冷媒が充分に存在すると仮定したときの入口温度理論値と、余剰冷媒がアキュムレータ等に貯留している状態で実際に計測された入口温度とを比較する。しかし、冷媒回路中の冷媒が漏洩しても、その分、アキュレータ等に貯留する冷媒が、冷媒回路中に流出するため、冷媒回路内に循環する冷媒の量は、アキュムレータ内に貯留する余剰冷媒がなくなるまで、ほぼ変化しない。即ち、計測される入口温度は、余剰冷媒以上の量の冷媒が漏洩するまで変化しない。このため、漏洩する量が少ない間は、冷媒の漏洩を検出することが困難である。 Further, in the inspection mode, the condensation temperature of the non-azeotropic refrigerant is set to be lower than that in the normal operation mode. Here, the amount of refrigerant in the circuit necessary for the operation of the refrigeration air conditioning apparatus 100 changes depending on the ambient temperature accompanying the seasonal fluctuation. Therefore, the refrigerant | coolant amount which assumed the largest required refrigerant | coolant amount is enclosed by the refrigerating air-conditioning apparatus 100. As shown in FIG. For this reason, the surplus refrigerant remains in the pressure vessel such as the accumulator 15 provided in the refrigerant circuit 10 for most of the period of one year. The conventional refrigerant shortage detection method compares the theoretical inlet temperature value assuming that the refrigerant is sufficiently present in the refrigeration circuit with the inlet temperature actually measured in a state where the surplus refrigerant is stored in the accumulator or the like. Do. However, even if the refrigerant in the refrigerant circuit leaks, the refrigerant stored in the accumulator flows out into the refrigerant circuit, and the amount of refrigerant circulating in the refrigerant circuit is the excess refrigerant stored in the accumulator. It will not change almost until there is no That is, the inlet temperature to be measured does not change until the amount of the refrigerant larger than the excess refrigerant leaks. Therefore, it is difficult to detect the refrigerant leakage while the amount of leakage is small.
　これに対し、本実施の形態１において、点検モード時は、通常運転モードと比較して、非共沸冷媒の凝縮温度が低くなるように設定される。凝縮温度が低くなると、その分過冷却度が増すため、液冷媒の密度が増加する。このため、冷媒回路１０内に循環する液冷媒の量が多くなり、アキュムレータ１５に残存する余剰冷媒が少なくなる。このように、余剰冷媒が少ない状態で点検が行われるため、少量の非共沸冷媒が漏洩しただけで、冷媒回路１０に流れる非共沸冷媒の組成が変化する。よって、非共沸冷媒が漏洩する量が少ない段階から非共沸冷媒の漏洩を検出することができる。例えば、アキュムレータ１５内に貯留する非共沸冷媒の量が多いと、冷媒回路１０内に循環する非共沸冷媒が漏洩しても、アキュムレータ１５から非共沸冷媒が冷媒回路１０内に流出するため、循環している非共沸冷媒の状態は変化しない。 On the other hand, in the first embodiment, in the inspection mode, the condensation temperature of the non-azeotropic refrigerant is set to be lower than that in the normal operation mode. As the condensation temperature decreases, the degree of subcooling increases accordingly, and the density of the liquid refrigerant increases. Therefore, the amount of liquid refrigerant circulating in the refrigerant circuit 10 increases, and the amount of surplus refrigerant remaining in the accumulator 15 decreases. As described above, since the inspection is performed in a state where the amount of surplus refrigerant is small, the composition of the non-azeotropic refrigerant flowing in the refrigerant circuit 10 changes only when a small amount of the non-azeotropic refrigerant leaks. Therefore, the leakage of the non-azeotropic refrigerant can be detected from the stage where the amount of the non-azeotropic refrigerant leaking is small. For example, when the amount of non-azeotropic refrigerant stored in the accumulator 15 is large, even if the non-azeotropic refrigerant circulating in the refrigerant circuit 10 leaks, the non-azeotropic refrigerant flows out from the accumulator 15 into the refrigerant circuit 10 Therefore, the state of the circulating non-azeotropic refrigerant does not change.
　本実施の形態１は、冷媒回路１０内に存在する余剰冷媒が少ない状態で点検が行われるため、少量の非共沸冷媒が漏洩しただけで、冷媒回路１０に流れる非共沸冷媒の組成が変化する。よって、冷媒が漏洩する量が少ない段階から非共沸冷媒の漏洩を検出することができる。これにより、地球環境への影響が懸念されるフロン冷媒を用いた冷凍空調装置１００であっても、環境面へ影響を減らすことができる。本実施の形態１において、低圧温度センサは、蒸発器１４に流入する冷媒の温度を検出する蒸発入口温度センサ２４である。非共沸冷媒は、温度勾配があるため、蒸発器１４に流入する非共沸冷媒の温度を用いて、冷媒漏洩の判定を行うことによって、冷媒漏洩の検出精度が高まる。また、蒸発器１４は、冷却室の冷却を行う。このように、蒸発器１４が設置される部屋の温度が安定化することによって、冷媒漏洩の検出精度が高まる。 In the first embodiment, since the inspection is performed in a state where there is little surplus refrigerant in the refrigerant circuit 10, the composition of the non-azeotropic refrigerant flowing in the refrigerant circuit 10 is only when a small amount of the non-azeotropic refrigerant leaks. Change. Therefore, the leakage of the non-azeotropic refrigerant can be detected from the stage where the amount of refrigerant leakage is small. Thereby, even if it is the frozen air conditioner 100 using the fluorocarbon refrigerant | coolant with the concern on the global environment, the environmental impact can be reduced. In the first embodiment, the low pressure temperature sensor is the evaporation inlet temperature sensor 24 that detects the temperature of the refrigerant flowing into the evaporator 14. Since the non-azeotropic refrigerant has a temperature gradient, the detection accuracy of the refrigerant leakage is improved by performing the determination of the refrigerant leakage using the temperature of the non-azeotropic refrigerant flowing into the evaporator 14. The evaporator 14 also cools the cooling chamber. Thus, by stabilizing the temperature of the room in which the evaporator 14 is installed, the detection accuracy of the refrigerant leakage is enhanced.
　また、本実施の形態１は、一時的に条件一定の運転が行われるため、点検モード時の冷媒貯留量は季節変動に依らず一定である。このため、季節変動に伴う余剰冷媒量の変化の影響を受けずに、冷媒の漏洩量が少ない段階から非共沸冷媒の漏洩を検出することができる。 Further, in the first embodiment, since the operation under a constant condition is performed temporarily, the refrigerant storage amount in the inspection mode is constant regardless of the seasonal fluctuation. For this reason, it is possible to detect the leakage of the non-azeotropic refrigerant from the stage where the amount of leakage of the refrigerant is small, without being affected by the change of the surplus refrigerant amount accompanying the seasonal fluctuation.
　従来の冷凍空調装置は、冷媒回路中に冷媒が充分に存在すると仮定したときに熱負荷によって求められる理論冷凍サイクルの蒸発器の入口温度理論値と、実際に計測された蒸発器の入口温度との差に基づいて、冷媒が不足していると判断する。蒸発器の入口温度の変化は、冷媒漏洩に伴う冷凍サイクル内の圧力低下によるものである。即ち、蒸発器の入口温度の変化が検出された時点では、冷媒不足による冷凍空調装置の冷却能力不足が発生している。このため、冷蔵庫及び対物空調用途といった冷却能力の低下が保管物の品質に直結する場合、保管物の劣化及び故障に至るおそれがある。 In the conventional refrigeration air conditioning system, the theoretical inlet temperature of the evaporator of the theoretical refrigeration cycle, which is determined by the heat load when it is assumed that the refrigerant is sufficiently present in the refrigerant circuit, and the inlet temperature of the evaporator actually measured. It is judged that the refrigerant is insufficient based on the difference of The change in evaporator inlet temperature is due to the pressure drop in the refrigeration cycle associated with refrigerant leakage. That is, when a change in the inlet temperature of the evaporator is detected, the cooling capacity of the refrigeration air conditioning system is insufficient due to the shortage of the refrigerant. For this reason, when a reduction in cooling capacity such as a refrigerator and an objective air conditioning application is directly linked to the quality of a stored item, the stored item may be deteriorated and broken.
　これに対し、本実施の形態１は、冷媒の漏洩量が少ない段階から非共沸冷媒の漏洩を検出するため、短時間の条件一定の運転を行うだけで、非共沸冷媒を検出することができる。例えば、除霜終了後のプルダウン運転等、冷凍サイクルの運用に必要で且つ保管物の品質に影響しないタイミングに、冷媒を検出することができる。このため、保管物の品質の劣化及び故障に至る入口温度の変化にまで至らない。 On the other hand, in the first embodiment, in order to detect the leakage of the non-azeotropic refrigerant from the stage where the leakage amount of the refrigerant is small, the non-azeotropic refrigerant is detected only by performing the operation with constant conditions for a short time. Can. For example, the refrigerant can be detected at a timing that is necessary for the operation of the refrigeration cycle, such as a pull-down operation after the end of defrosting, and does not affect the quality of stored items. For this reason, it does not lead to the change of the inlet temperature leading to deterioration and failure of the quality of stored goods.
　更に、スプリットタイプの機器のように、負荷装置の組み合わせ及び現地配管長が変化する場合、現地配管内で生じる圧力損失の影響等によって、理論冷凍サイクルの状態が変化する。従来の冷凍空調装置は、冷凍回路中に冷媒量が必要量存在すると仮定して熱負荷によって理論冷凍サイクルを演算する手法を用いている。このため、演算によって求められる理論冷凍サイクルと、実運転上の理論冷凍サイクルとが不一致となり、冷媒の漏洩を正しく検出することができない。これに対し、本実施の形態１は、条件一定の運転を行っている。このため、現地配管内での圧力損失に起因する高圧圧力及び低圧圧力の変化、立ち上がり配管長さの影響による過冷却度の変化等、現地における施工条件の影響を受けることなく、冷媒の漏洩を正確に検出することができる。 Furthermore, when the combination of load devices and the on-site piping length change, as in a split-type device, the state of the theoretical refrigeration cycle changes due to the effect of pressure loss occurring in the on-site piping. The conventional refrigeration air conditioning system uses a method of computing a theoretical refrigeration cycle based on heat load, assuming that a necessary amount of refrigerant is present in a refrigeration circuit. For this reason, the theoretical refrigeration cycle determined by calculation and the theoretical refrigeration cycle in actual operation do not match, and the refrigerant leakage can not be detected correctly. On the other hand, in the first embodiment, the operation under constant conditions is performed. For this reason, the refrigerant leaks without being affected by the on-site construction conditions such as changes in high pressure and low pressure due to pressure loss in the on-site piping and changes in the degree of supercooling due to the effect of rising pipe length. It can be detected accurately.
　なお、本実施の形態１では、除霜運転終了後のように、連続運転が可能な特定条件下において点検モードを実行している場合について例示しているが、装置内温度が目標装置内温度に達しても、サーモ停止せずに運転を継続するように制御してもよい。これにより、点検モードが確実に実行される。このように、本実施の形態１は、点検モード時において、冷却対象の空気温度が温度閾値に到達しても、冷媒回路１０の動作を継続するように制御してもよい。 Although Embodiment 1 exemplifies the case where the inspection mode is executed under specific conditions that allow continuous operation, such as after completion of the defrosting operation, the in-device temperature is the target in-device temperature. However, control may be performed to continue the operation without stopping the thermo. This ensures that the inspection mode is performed. As described above, in the first embodiment, in the inspection mode, even if the temperature of the air to be cooled reaches the temperature threshold, control may be performed to continue the operation of the refrigerant circuit 10.
　また、本実施の形態１では、低圧圧力の飽和温度と蒸発器１４の入口温度との関係が、判定条件を５分以上連続して満足する場合に非共沸冷媒が漏洩していると判定している。ここで、制御装置５０は、入口温度を、一定時間ごとに複数回取得してもよい。この場合、制御装置５０は、例えば経時的に複数の計測値を３０秒間隔で平均して、平均値が判定条件を１０回連続で満足する場合に非共沸冷媒が漏洩していると判定する。これにより、計測値が蒸発負荷の変動、蒸発器１４の出口側の温度の変化及び電気的ノイズ等の外乱要因の影響を受けて急激に変動しても、急激な値の変化の影響が小さくなる。よって、実際に冷媒の漏洩が発生した場合に連続検出の条件から外れることなく、判定結果の信頼性を向上させることができる。 Further, in the first embodiment, it is determined that the non-azeotropic refrigerant is leaking when the relationship between the saturation temperature of the low pressure and the inlet temperature of the evaporator 14 continuously satisfies the determination condition for 5 minutes or more. doing. Here, the control device 50 may acquire the inlet temperature a plurality of times at fixed time intervals. In this case, the control device 50 determines that the non-azeotropic refrigerant is leaking when, for example, the plurality of measured values are averaged over a 30-second interval with time and the average value satisfies the determination condition ten consecutive times. Do. As a result, even if the measured value fluctuates rapidly under the influence of disturbance factors such as the fluctuation of evaporation load, the change of temperature on the outlet side of the evaporator 14, and the electrical noise, the influence of the rapid change of value is small. Become. Therefore, when the leakage of the refrigerant actually occurs, the reliability of the determination result can be improved without deviating from the condition of the continuous detection.
実施の形態２．
　図６は、本発明の実施の形態２における非共沸冷媒であるＲ４２２Ａ、Ｒ４２２Ｄ及びＲ４１７Ａを構成する冷媒の沸点及び組成比率を示す表である。本実施の形態２は、複数種の冷媒において漏洩を検出することができる点で、実施の形態１と相違する。本実施の形態２では、実施の形態１と同一の部分は同一の符号を付して説明を省略し、実施の形態１との相違点を中心に説明する。 Second Embodiment
FIG. 6 is a table showing boiling points and composition ratios of refrigerants constituting the non-azeotropic refrigerants R422A, R422D and R417A according to the second embodiment of the present invention. The second embodiment is different from the first embodiment in that leakage can be detected in a plurality of refrigerants. In the second embodiment, the same parts as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. The differences from the first embodiment will be mainly described.
　冷媒回路１０の構成は、実施の形態１と共通するが、本実施の形態２は、使用冷媒を制御装置５０において選択可能であり、Ｒ４２２Ａ、Ｒ４２２Ｄ及びＲ４１７Ａの全てを採用することができる。図６に示すように、Ｒ４２２Ａの組成比率は、Ｒ１２５が８５．１％であり、Ｒ１３４ａが１１．５％であり、Ｒ６００ａが３．４％である。Ｒ４２２Ｄの組成比率は、Ｒ１２５が６５．１％であり、Ｒ１３４ａが３１．５％であり、Ｒ６００ａが３．４％である。Ｒ４１７Ａの組成比率は、Ｒ１２５が４６．６％であり、Ｒ１３４ａが５０．０％であり、Ｒ６００が３．４％である。なお、沸点は、Ｒ１２５が－４８．１℃であり、Ｒ１３４ａが－２６．１℃であり、Ｒ６００ａが－１１．７℃であり、Ｒ６００が－０．５５℃である。即ち、Ｒ１３４ａ、Ｒ６００ａ及びＲ６００が、Ｒ１２５よりも沸点が高い。 The configuration of the refrigerant circuit 10 is the same as that of the first embodiment. In the second embodiment, the used refrigerant can be selected by the control device 50, and all of R422A, R422D, and R417A can be adopted. As shown in FIG. 6, the composition ratio of R422A is 85.1% for R125, 11.5% for R134a, and 3.4% for R600a. The composition ratio of R422D is 65.1% for R125, 31.5% for R134a, and 3.4% for R600a. The compositional ratio of R417A is 46.6% for R125, 50.0% for R134a, and 3.4% for R600. The boiling point of R125 is -48.1 ° C, R134a is -26.1 ° C, R600a is -11.7 ° C, and R600 is -0.55 ° C. That is, R134a, R600a and R600 have boiling points higher than R125.
　ここで、Ｒ１２５を第１の冷媒グループと呼称し、Ｒ１３４ａ、Ｒ６００ａ及びＲ６００を第２の冷媒グループと呼称する。Ｒ４２２Ｄ及びＲ４１７Ａは、第２の冷媒グループの組成比率が３０％以上であり、Ｒ４２２Ａは、第２の冷媒グループの組成比率が３０％未満である。なお、実施の形態１で例示するＲ４０７Ｃは、Ｒ３２及びＲ１２５を第１の冷媒グループとし、Ｒ３２及びＲ１２５より沸点が高いＲ１３４ａを第２の冷媒グループとすると、第２の冷媒グループの組成比率が３０％以上である。このように、制御装置５０は、非共沸冷媒の種類を、第１の冷媒グループと、第１の冷媒グループよりも沸点が高い第２の冷媒グループと、に分類して設定する。 Here, R125 is referred to as a first refrigerant group, and R134a, R600a, and R600 are referred to as a second refrigerant group. In R422D and R417A, the composition ratio of the second refrigerant group is 30% or more, and in R422A, the composition ratio of the second refrigerant group is less than 30%. In addition, R407C illustrated in the first embodiment has R32 and R125 as the first refrigerant group, and R134a having a boiling point higher than R32 and R125 as the second refrigerant group, the composition ratio of the second refrigerant group is 30. % Or more. Thus, the control device 50 classifies and sets the type of non-azeotropic refrigerant into the first refrigerant group and the second refrigerant group having a boiling point higher than that of the first refrigerant group.
　本実施の形態２では、減算閾値は、非共沸冷媒の種類に基づいて設定される。例えば、減算閾値は、第２の冷媒グループの組成比率に基づいて設定される。減算閾値は、予め記憶されたテーブルで対応づけされていてもよいし、個別に設定されてもよい。 In the second embodiment, the subtraction threshold is set based on the type of non-azeotropic refrigerant. For example, the subtraction threshold is set based on the composition ratio of the second refrigerant group. The subtraction threshold may be associated with a table stored in advance, or may be set individually.
　図７は、本発明の実施の形態２におけるＲ４２２Ａの組成変化に伴う各部温度を示す表である。図７に示すように、図３のＡ点の温度が４５℃であり、Ｂ点の温度が４０℃であり、Ｃ点の温度が－２０．３℃である。なお、－２０．３℃は、組成比率が適切な場合を想定したときの低圧圧力の飽和温度理論値である。図７に示すように、冷媒の漏洩が進行するに従って、低圧圧力を一定値としたときの飽和温度が上昇する。Ｃ点の温度変化は、１５％漏洩したときに０．５Ｋである。 FIG. 7 is a table showing the temperature of each part according to the composition change of R422A in the second embodiment of the present invention. As shown in FIG. 7, the temperature at point A in FIG. 3 is 45 ° C., the temperature at point B is 40 ° C., and the temperature at point C is −20.3 ° C. Incidentally, -20.3 ° C. is a theoretical value of saturation temperature of low pressure when it is assumed that the composition ratio is appropriate. As shown in FIG. 7, as the leakage of the refrigerant progresses, the saturation temperature increases when the low pressure is a constant value. The temperature change at point C is 0.5 K when it leaks 15%.
　図８は、本発明の実施の形態２におけるＲ４２２Ｄの組成変化に伴う各部温度を示す表である。図８に示すように、図３のＡ点の温度が４５℃であり、Ｂ点の温度が４０℃であり、Ｃ点の温度が－１５．６℃である。なお、－１５．６℃は、組成比率が適切な場合を想定したときの低圧圧力の飽和温度理論値である。図８に示すように、冷媒の漏洩が進行するに従って、低圧圧力を一定値としたときの飽和温度が上昇する。Ｃ点の温度変化は、１５％漏洩したときに１．２Ｋである。 FIG. 8 is a table showing the temperature of each part according to the change in composition of R422D in the second embodiment of the present invention. As shown in FIG. 8, the temperature at point A in FIG. 3 is 45 ° C., the temperature at point B is 40 ° C., and the temperature at point C is -15.6 ° C. Here, -15.6 ° C. is a theoretical value of saturation temperature of low pressure when it is assumed that the composition ratio is appropriate. As shown in FIG. 8, as the leakage of the refrigerant progresses, the saturation temperature rises when the low pressure is a constant value. The temperature change at point C is 1.2 K when it leaks 15%.
　図９は、本発明の実施の形態２におけるＲ４１７Ａの組成変化に伴う各部温度を示す表である。図９に示すように、図３のＡ点の温度が４５℃であり、Ｂ点の温度が４０℃であり、Ｃ点の温度が－１１．０℃である。なお、－１１．０℃は、組成比率が適切な場合を想定したときの低圧圧力の飽和温度理論値である。図９に示すように、冷媒の漏洩が進行するに従って、低圧圧力を一定値としたときの飽和温度が上昇する。Ｃ点の温度変化は、１０％漏洩したときに１．２Ｋであり、１５％漏洩したときに１．９Ｋである。 FIG. 9 is a table showing the temperatures of respective portions according to the composition change of R417A in the second embodiment of the present invention. As shown in FIG. 9, the temperature at point A in FIG. 3 is 45 ° C., the temperature at point B is 40 ° C., and the temperature at point C is −11.0 ° C. Here, −11.0 ° C. is a theoretical value of the saturation temperature of the low pressure when it is assumed that the composition ratio is appropriate. As shown in FIG. 9, as the leakage of refrigerant progresses, the saturation temperature when the low pressure is a constant value rises. The temperature change at point C is 1.2 K when 10% leaks and 1.9 K when 15% leaks.
　以上のとおり、同一又は類似冷媒によって構成される非共沸冷媒であっても、高沸点冷媒である第２の冷媒グループ（図７～図９の網掛け部）の組成比率によって、Ｃ点の温度の推移が変わる。そこで、本実施の形態２では、減算閾値が、第２の冷媒グループの組成比率に基づいて設定される。例えば、Ｒ４２２Ａでは、図７に示すように、減算閾値が０．５Ｋに設定されることによって、冷媒が１５％漏洩した時点で検出される。また、Ｒ４２２Ｄでは、図８に示すように、減算閾値が１．０Ｋに設定されることによって、冷媒が１０％漏洩した時点で検出される。Ｒ４１７Ａでは、図９に示すように、減算閾値が１．０Ｋに設定されることによって、冷媒が１５％漏洩した時点で検出される。このように、第２の冷媒グループの組成比率に基づいて減算閾値が変更されることによって、複数の冷媒の漏洩を検出することができる。 As described above, even if it is a non-azeotropic refrigerant composed of the same or similar refrigerants, the composition ratio of the second refrigerant group (shaded part in FIGS. The transition of temperature changes. Therefore, in the second embodiment, the subtraction threshold is set based on the composition ratio of the second refrigerant group. For example, in R422A, as shown in FIG. 7, the subtraction threshold value is set to 0.5 K, which is detected when the refrigerant leaks 15%. Further, in R422D, as shown in FIG. 8, the subtraction threshold is set to 1.0 K, so that detection is performed when the refrigerant leaks 10%. In R 417 A, as shown in FIG. 9, the subtraction threshold value is set to 1.0 K, so that it is detected when the refrigerant leaks 15%. As described above, the leak threshold of the plurality of refrigerants can be detected by changing the subtraction threshold based on the composition ratio of the second refrigerant group.
　なお、制御装置５０は、前述の点検モードとは異なる点検モードを実行するようにしてもよい。Ｒ４２２Ａのように、第２の冷媒グループの組成比率が３０％未満である場合、冷媒が１５％漏洩しても、Ｃ点の温度変化は０．５Ｋと小さい。このため、減算閾値を０．５Ｋのように小さくする必要が生じるが、この場合、計測バラツキによって、誤って漏洩が検出されるおそれがある。また、減算閾値を１．０Ｋとすると、温度差が１．２Ｋとなる３０％近くまで漏洩するまで、漏洩を検出することができない。そこで、冷媒の種類に応じて、複数の点検モードを使い分けてもよい。 Control device 50 may execute an inspection mode different from the above-described inspection mode. When the composition ratio of the second refrigerant group is less than 30% as in R422A, the temperature change at point C is as small as 0.5 K even if the refrigerant leaks 15%. Therefore, it is necessary to reduce the subtraction threshold value to 0.5 K, but in this case, there is a possibility that the leakage may be erroneously detected due to the measurement variation. Also, assuming that the subtraction threshold value is 1.0 K, the leakage can not be detected until the temperature difference leaks to nearly 30% at which the temperature difference is 1.2 K. Therefore, depending on the type of refrigerant, a plurality of inspection modes may be used properly.
　例えば、制御装置５０は、Ｒ４２２Ａのように、第２の冷媒グループの組成比率が第１の冷媒グループの組成比率よりも低い冷媒が選択された場合、従来のように蒸発器１４の入口温度と理論値との差異に基づいて漏洩の有無を判定する検出モードを実行する。また、制御装置５０は、Ｒ４２２Ｄ又はＲ４１７Ａのように、第２の冷媒グループの組成比率が第１の冷媒グループの組成比率よりも高い冷媒が選択された場合、実施の形態１の点検モードを実行する。これにより、冷媒の種類に応じた漏洩検出をすることができ、冷媒の漏洩量の減少に寄与する。 For example, when a refrigerant whose composition ratio of the second refrigerant group is lower than the composition ratio of the first refrigerant group is selected as in R422A, the control device 50 selects the inlet temperature of the evaporator 14 as in the conventional case. A detection mode is executed to determine the presence or absence of leakage based on the difference from the theoretical value. Further, as in the case of R422D or R417A, control device 50 executes the inspection mode of the first embodiment when a refrigerant having a composition ratio of the second refrigerant group higher than that of the first refrigerant group is selected. Do. As a result, leakage detection can be performed according to the type of refrigerant, which contributes to a reduction in the amount of refrigerant leakage.
実施の形態３．
　図１０は、本発明の実施の形態３に係る冷凍空調装置２００を示す回路図である。本実施の形態３は、液だめ３３を備えている点で、実施の形態１と相違する。本実施の形態３では、実施の形態１と同一の部分は同一の符号を付して説明を省略し、実施の形態１との相違点を中心に説明する。 Third Embodiment
FIG. 10 is a circuit diagram showing a refrigeration air conditioning system 200 according to Embodiment 3 of the present invention. The third embodiment is different from the first embodiment in that the liquid reservoir 33 is provided. In the third embodiment, the same parts as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. The differences from the first embodiment will be mainly described.
　図１０に示すように、液だめ３３は、凝縮器１２と膨張部１３との間に接続されており、余剰冷媒を貯留する。通常の冷却運転時には、液だめ３３の内部に余剰冷媒が貯蔵され、液だめ３３の出口からは液相の冷媒が流出する。このため、封入される冷媒が非共沸冷媒であっても、冷媒回路１０内を流れる冷媒は、封入時のままとなる。本実施の形態３では、制御装置５０は、点検モードの実行前に、冷媒回路１０に流れる非共沸冷媒のうち余剰冷媒が、低圧側の圧力容器であるアキュムレータ１５に移動させる運転を行った後、点検モードを実行する。 As shown in FIG. 10, the liquid reservoir 33 is connected between the condenser 12 and the expansion section 13 and stores excess refrigerant. During normal cooling operation, the excess refrigerant is stored inside the liquid reservoir 33, and the liquid phase refrigerant flows out from the outlet of the liquid reservoir 33. For this reason, even if the refrigerant to be sealed is a non-azeotropic refrigerant, the refrigerant flowing in the refrigerant circuit 10 remains at the time of sealing. In the third embodiment, the control device 50 performs the operation of moving the surplus refrigerant out of the non-azeotropic refrigerant flowing in the refrigerant circuit 10 to the accumulator 15 which is the pressure vessel on the low pressure side before the execution of the inspection mode. After, execute the inspection mode.
　これは、例えば、蒸発器１４のファン（図示せず）を一時的に停止させること等によって実現できる。これにより、冷媒回路１０内を流れるＲ３２及びＲ１２５の組成比率が高くなり、冷媒の漏洩が発生している状況の場合、冷媒の組成変化が発生する。この状態で、一定時間冷却運転が行われ、制御装置５０が冷媒の漏洩の有無を判定する。 This can be realized, for example, by temporarily stopping the fan (not shown) of the evaporator 14 or the like. As a result, the composition ratio of R32 and R125 flowing in the refrigerant circuit 10 becomes high, and when the refrigerant leaks, the composition change of the refrigerant occurs. In this state, the cooling operation is performed for a fixed time, and the controller 50 determines the presence or absence of the refrigerant leakage.
　その後、図５の点検モードに移行する。上記のとおり、冷媒の漏洩が発生している状況であれば、冷媒の組成変化が発生するため、図３のＣ点の温度が変化する。よって、実施の形態３においても、実施の形態１と同様に、冷媒の漏洩を検出することができる。なお、本実施の形態３では、低温機器等のような一般的な液だめ３３を備える回路構成であっても、組成変化による漏洩検出をすることができるものであり、より広範囲の製品群において冷媒の漏洩を検出することができる。なお、本実施の形態３においても、実施の形態２のように、複数の冷媒において漏洩を検出するように構成されてもよい。 After that, it shifts to the inspection mode in FIG. As described above, if the refrigerant leaks, the composition of the refrigerant changes, so the temperature at point C in FIG. 3 changes. Therefore, also in the third embodiment, as in the first embodiment, the leakage of the refrigerant can be detected. In the third embodiment, even in a circuit configuration provided with a general liquid reservoir 33 such as a low temperature device or the like, leakage detection due to composition change can be performed, and a broader range of product groups can be used. Leakage of refrigerant can be detected. Also in the third embodiment, as in the second embodiment, leakage may be detected in a plurality of refrigerants.
　１０　冷媒回路、１１　圧縮機、１２　凝縮器、１３　膨張部、１４　蒸発器、１５　アキュムレータ、２１　凝縮温度センサ、２２　膨張入口温度センサ、２３　低圧圧力センサ、２４　蒸発入口温度センサ、３３　液だめ、５０　制御装置、１００　冷凍空調装置、３００　冷凍空調装置。 Reference Signs List 10 refrigerant circuit, 11 compressor, 12 condenser, 13 expansion unit, 14 evaporator, 15 accumulator, 21 condensation temperature sensor, 22 expansion inlet temperature sensor, 23 low pressure sensor, 24 evaporation inlet temperature sensor, 33 liquid reservoir, 50 Control device, 100 refrigeration air conditioner, 300 refrigeration air conditioner.

Claims (20)

  1. 　圧縮機、凝縮器、膨張部及び蒸発器が配管により接続され、非共沸冷媒が循環する冷媒回路と、
    　前記冷媒回路の低圧の前記非共沸冷媒の温度を検出する低圧温度センサと、
    　前記冷媒回路の低圧を設定圧力に保つ点検条件で前記冷媒回路を動作させて、前記低圧温度センサが検出した温度を用いて前記非共沸冷媒の漏洩の有無を判定する点検モードを有する制御装置と、
    　を備える冷凍空調装置。     A refrigerant circuit in which a compressor, a condenser, an expansion unit, and an evaporator are connected by piping and in which a non-azeotropic refrigerant circulates;
    A low pressure temperature sensor for detecting a temperature of the low pressure non-azeotropic refrigerant in the refrigerant circuit;
    A control device having an inspection mode for operating the refrigerant circuit under an inspection condition for maintaining the low pressure of the refrigerant circuit at a set pressure and determining the presence or absence of the non-azeotropic refrigerant leakage using the temperature detected by the low pressure temperature sensor When,
    Refrigeration air conditioner provided with.
  2. 　前記低圧温度センサは、前記蒸発器に流入する前記非共沸冷媒の温度を検出するものである
    　請求項１に記載の冷凍空調装置。     The refrigeration air conditioning system according to claim 1, wherein the low pressure temperature sensor detects a temperature of the non-azeotropic refrigerant flowing into the evaporator.
  3. 　前記蒸発器は、冷却室の冷却を行うものである
    　請求項１又は２に記載の冷凍空調装置。     The refrigeration air conditioner according to claim 1, wherein the evaporator performs cooling of a cooling chamber.
  4. 　前記設定圧力から換算される前記非共沸冷媒の蒸発温度が、前記冷却室の設定温度よりも高い
    　請求項３に記載の冷凍空調装置。     The refrigeration air conditioning system according to claim 3, wherein the evaporation temperature of the non-azeotropic refrigerant converted from the set pressure is higher than the set temperature of the cooling chamber.
  5. 　前記点検モード時は、通常運転モードと比較して、前記非共沸冷媒の凝縮温度が低くなるように設定される
    　請求項１～４のいずれか１項に記載の冷凍空調装置。     The refrigeration air-conditioning apparatus according to any one of claims 1 to 4, wherein, in the inspection mode, the condensation temperature of the non-azeotropic refrigerant is set to be lower than that in the normal operation mode.
  6. 　前記点検条件は、
    　前記凝縮器に流れる前記非共沸冷媒の凝縮温度と、前記膨張部の入口側に流れる前記非共沸冷媒の過冷却度と、前記蒸発器の入口側に流れる前記非共沸冷媒の低圧圧力とが、目標値となる条件である
    　請求項１～５のいずれか１項に記載の冷凍空調装置。     The inspection condition is
    The condensation temperature of the non-azeotropic refrigerant flowing to the condenser, the degree of supercooling of the non-azeotropic refrigerant flowing to the inlet side of the expansion unit, and the low pressure pressure of the non-azeotropic refrigerant flowing to the inlet side of the evaporator The refrigeration air-conditioning apparatus according to any one of claims 1 to 5, wherein is a condition to be a target value.
  7. 　前記点検条件は、
    　前記凝縮器に流れる前記非共沸冷媒の高圧圧力と、前記膨張部の入口側に流れる前記非共沸冷媒の過冷却度と、前記蒸発器の入口側に流れる前記非共沸冷媒の低圧圧力とが、目標値となる条件である
    　請求項１～５のいずれか１項に記載の冷凍空調装置。     The inspection condition is
    High pressure of the non-azeotropic refrigerant flowing to the condenser, degree of supercooling of the non-azeotropic refrigerant flowing to the inlet side of the expansion unit, and low pressure of the non-azeotropic refrigerant flowing to the inlet side of the evaporator The refrigeration air-conditioning apparatus according to any one of claims 1 to 5, wherein is a condition to be a target value.
  8. 　前記制御装置は、
    　前記蒸発器の入口側に流れる前記非共沸冷媒の入口温度から、前記蒸発器の入口側に流れる前記非共沸冷媒の入口圧力から求められる飽和温度理論値を減算した減算値が減算閾値を超える場合、前記非共沸冷媒が漏洩したと判定する
    　請求項１～７のいずれか１項に記載の冷凍空調装置。     The controller is
    A subtraction value obtained by subtracting a theoretical saturation temperature value obtained from the inlet pressure of the non-azeotropic refrigerant flowing to the inlet side of the evaporator from the inlet temperature of the non-azeotropic refrigerant flowing to the inlet side of the evaporator is a subtraction threshold The refrigeration air-conditioning apparatus according to any one of claims 1 to 7, wherein it is determined that the non-azeotropic refrigerant has leaked if it exceeds.
  9. 　前記減算閾値は、
    　前記非共沸冷媒の種類に基づいて設定される
    　請求項８に記載の冷凍空調装置。     The subtraction threshold is
    The refrigeration air conditioning system according to claim 8, wherein the refrigeration air conditioning system is set based on a type of the non-azeotropic refrigerant.
  10. 　前記制御装置は、
    　前記非共沸冷媒の種類を、
    　第１の冷媒グループと、
    　前記第１の冷媒グループよりも沸点が高い第２の冷媒グループと、に分類して設定し、
    　前記減算閾値は、
    　前記第２の冷媒グループの組成比率に基づいて設定される
    　請求項８又は９に記載の冷凍空調装置。     The controller is
    The type of non-azeotropic refrigerant,
    A first refrigerant group,
    The second refrigerant group having a boiling point higher than that of the first refrigerant group is classified and set.
    The subtraction threshold is
    The refrigeration air conditioning system according to claim 8 or 9, wherein the refrigeration air conditioning system is set based on a composition ratio of the second refrigerant group.
  11. 　前記制御装置は、
    　前記入口温度を、一定時間毎に複数回取得する
    　請求項８～１０のいずれか１項に記載の冷凍空調装置。     The controller is
    The refrigeration air-conditioning apparatus according to any one of claims 8 to 10, wherein the inlet temperature is acquired a plurality of times at fixed time intervals.
  12. 　前記冷媒回路は、
    　前記凝縮器と前記膨張部との間に、冷媒を貯留する液だめが接続されている
    　請求項１～１１のいずれか１項に記載の冷凍空調装置。     The refrigerant circuit is
    The refrigeration air conditioning system according to any one of claims 1 to 11, wherein a liquid reservoir for storing a refrigerant is connected between the condenser and the expansion unit.
  13. 　冷媒を貯留するアキュムレータを更に備え、
    　前記制御装置は、
    　前記冷媒回路に流れる前記非共沸冷媒のうち余剰となった余剰冷媒を、前記アキュムレータに移動させる運転を行った後、前記点検モードを実行する
    　請求項１２に記載の冷凍空調装置。     It further comprises an accumulator for storing the refrigerant,
    The controller is
    The refrigeration air-conditioning apparatus according to claim 12, wherein the check mode is performed after an operation of moving a surplus surplus refrigerant out of the non-azeotropic refrigerant flowing in the refrigerant circuit to the accumulator is performed.
  14. 　前記制御装置は、
    　前記非共沸冷媒を、
    　第１の冷媒グループと、
    　前記第１の冷媒グループよりも沸点が高い第２の冷媒グループと、に分類して設定し、
    　前記第２の冷媒グループの組成比率は３０％以上である
    　請求項１～１３のいずれか１項に記載の冷凍空調装置。     The controller is
    The non-azeotropic refrigerant is
    A first refrigerant group,
    The second refrigerant group having a boiling point higher than that of the first refrigerant group is classified and set.
    The refrigeration air conditioner according to any one of claims 1 to 13, wherein a composition ratio of the second refrigerant group is 30% or more.
  15. 　前記制御装置は、
    　前記非共沸冷媒は、
    　第１の冷媒グループと、
    　前記第１の冷媒グループよりも沸点が高い第２の冷媒グループと、に分類して設定し、
    　前記第２の冷媒グループの組成比率は３０％未満である
    　請求項１～１４のいずれか１項に記載の冷凍空調装置。     The controller is
    The non-azeotropic refrigerant is
    A first refrigerant group,
    The second refrigerant group having a boiling point higher than that of the first refrigerant group is classified and set.
    The refrigeration air conditioning system according to any one of claims 1 to 14, wherein a composition ratio of the second refrigerant group is less than 30%.
  16. 　前記制御装置は、
    　前記第２の冷媒グループの組成比率が３０％以上である場合、前記点検モードを実行する
    　請求項１４又は１５に記載の冷凍空調装置。     The controller is
    The refrigeration air conditioner according to claim 14 or 15, wherein the inspection mode is executed when the composition ratio of the second refrigerant group is 30% or more.
  17. 　前記点検モードは、
    　除霜運転が終了した後に実行される
    　請求項１～１６のいずれか１項に記載の冷凍空調装置。     The inspection mode is
    The refrigeration air conditioning system according to any one of claims 1 to 16, which is executed after the defrosting operation is finished.
  18. 　前記制御装置は、
    　前記点検モード時において、冷却対象の空気温度が温度閾値に到達しても、前記冷媒回路の動作を継続するように制御する
    　請求項１～１７のいずれか１項に記載の冷凍空調装置。     The controller is
    The refrigeration air-conditioning apparatus according to any one of claims 1 to 17, wherein, in the inspection mode, even if the temperature of air to be cooled reaches a temperature threshold, the operation of the refrigerant circuit is continued.
  19. 　前記非共沸冷媒は、
    　Ｒ４０７Ｃ、Ｒ４２２Ａ、Ｒ４２２Ｄ又はＲ４１７Ａである
    　請求項１～１８のいずれか１項に記載の冷凍空調装置。     The non-azeotropic refrigerant is
    The refrigeration air conditioning system according to any one of claims 1 to 18, which is R407C, R422A, R422D or R417A.
  20. 　圧縮機、凝縮器、膨張部及び蒸発器が配管により接続され、非共沸冷媒が循環する冷媒回路と、前記冷媒回路の低圧の前記非共沸冷媒の温度を検出する低圧温度センサと、を備える冷凍空調装置を制御する制御装置であって、
    　前記冷媒回路の低圧を設定圧力に保つ点検条件で前記冷媒回路を動作させて、前記低圧温度センサが検出した温度を用いて前記非共沸冷媒の漏洩の有無を判定する点検モードを有する
    　制御装置。     A refrigerant circuit in which a compressor, a condenser, an expansion unit, and an evaporator are connected by piping and in which a non-azeotropic refrigerant circulates; and a low pressure temperature sensor for detecting the temperature of the low pressure non-azeotropic refrigerant of the refrigerant circuit A control device for controlling a refrigeration air conditioner provided therein,
    A control device having an inspection mode for operating the refrigerant circuit under an inspection condition for keeping the low pressure of the refrigerant circuit at a set pressure, and determining the presence or absence of the non-azeotropic refrigerant leakage using the temperature detected by the low pressure temperature sensor. .
PCT/JP2017/027288 2017-07-27 2017-07-27 Refrigeration and air conditioning device, and control device WO2019021428A1 (en)

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Cited By (1)

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WO2024009394A1 (en) * 2022-07-05 2024-01-11 三菱電機株式会社 Air conditioner and refrigerant leak detection method

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JPH0886545A (en) * 1994-09-14 1996-04-02 Sanyo Electric Co Ltd Vapor compression type refrigerator
JP2003042655A (en) * 2001-07-27 2003-02-13 Toshiba Corp Refrigerator
JP2015135192A (en) * 2014-01-16 2015-07-27 株式会社富士通ゼネラル Air conditioning device

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Publication number Priority date Publication date Assignee Title
JP2008025935A (en) 2006-07-24 2008-02-07 Daikin Ind Ltd Air conditioner

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Publication number Priority date Publication date Assignee Title
JPH0886545A (en) * 1994-09-14 1996-04-02 Sanyo Electric Co Ltd Vapor compression type refrigerator
JP2003042655A (en) * 2001-07-27 2003-02-13 Toshiba Corp Refrigerator
JP2015135192A (en) * 2014-01-16 2015-07-27 株式会社富士通ゼネラル Air conditioning device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024009394A1 (en) * 2022-07-05 2024-01-11 三菱電機株式会社 Air conditioner and refrigerant leak detection method

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