Refrigerant leakage detection system, refrigerant leakage detection method, and refrigeration cycle apparatus

Abstract

In the conventional refrigerant leakage detection method, when a failure occurs in the temperature sensor or the pressure sensor, the refrigerant leakage may not be detected.SOLUTION: The refrigerant leakage detection system 1 includes the chiller 10 and the input unit 110. The chilled water chiller 10 has a refrigerant circuit 50 through which a refrigerant circulates. The input unit 110 acquires the degree of supercooling and the expansion valve opening degree from the cold water chiller 10. The controller 120 performs refrigerant leakage determination using the degree of subcooling, or refrigerant leakage determination using the expansion valve opening degree. When the priority of the refrigerant leak determination using the degree of subcooling is higher than the priority of the refrigerant leak determination using the expansion valve opening degree, the controller 120 switches between the refrigerant leak determination using the degree of subcooling and the refrigerant leak determination using the expansion valve opening degree on the basis of whether or not the degree of subcooling is normal.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a refrigerant leak detection system, a refrigerant leak detection method, and a refrigeration cycle device. [Background technology]

[0002] Conventionally, refrigerant leakage occurring in a refrigeration cycle has been detected using the outputs of a temperature sensor, a pressure sensor, etc. (Patent Document 1 (JP 2019-2639 A)). Summary of the Invention [Problem to be solved by the invention]

[0003] However, conventional refrigerant leak detection methods have the problem that they may not be able to detect a refrigerant leak if a temperature sensor or pressure sensor fails, or if an expansion valve fails or a communication error occurs. [Means for solving the problem]

[0004] A refrigerant leak detection system according to a first aspect includes a refrigeration cycle device and a data acquisition unit. The refrigeration cycle device has a refrigerant circuit through which a refrigerant circulates. The data acquisition unit acquires first operating data and second operating data from the refrigeration cycle device. The control unit performs a first refrigerant leak determination using the first operating data or a second refrigerant leak determination using the second operating data. When the priority of the first refrigerant leak determination is higher than the priority of the second refrigerant leak determination, the control unit switches between the first refrigerant leak determination and the second refrigerant leak determination based on whether the first operating data is normal.

[0005] In this refrigerant leak detection system, by switching to one of a plurality of refrigerant leak determinations based on whether the first operating data is normal or not, it is possible to detect a refrigerant leak even if the first operating data is abnormal.

[0006] A refrigerant leak detection system according to a second aspect is the system according to the first aspect, wherein the control unit selects a first refrigerant leak determination using the first operating data when the first operating data is normal, and selects a second refrigerant leak determination using the second operating data when the first operating data is abnormal.

[0007] In this refrigerant leak detection system, by selecting the second refrigerant leak determination when the first operating data is abnormal, it is possible to detect a refrigerant leak even if the first operating data is abnormal.

[0008] A refrigerant leak detection system of a third aspect is a system of the first or second aspect, in which the control unit uses a predicted value of the degree of subcooling, a predicted value of the discharge superheat, or a predicted value of the expansion valve opening as the first operating data and the second operating data.

[0009] In this refrigerant leakage detection system, a refrigerant leakage can be detected using a predicted value of the degree of subcooling, a predicted value of the discharge superheat, or a predicted value of the expansion valve opening as the first operating data and the second operating data.

[0010] A refrigerant leak detection system according to a fourth aspect is the system according to any one of the first to third aspects, wherein the data acquisition unit includes at least one of a condenser inlet temperature sensor, a condenser outlet temperature sensor, and a discharge temperature sensor.

[0011] In this refrigerant leakage detection system, the degree of supercooling, the degree of discharge superheat, or the degree of expansion valve opening can be acquired as operating data.

[0012] A refrigerant leak detection method according to a fifth aspect includes a data acquisition step and a control step. The data acquisition step acquires first operating data and second operating data from a refrigeration cycle device having a refrigerant circuit through which a refrigerant circulates. The control step performs a first refrigerant leak determination using the first operating data or a second refrigerant leak determination using the second operating data. The control step switches between the first refrigerant leak determination and the second refrigerant leak determination based on whether the first operating data is normal when the priority of the first refrigerant leak determination is higher than the priority of the second refrigerant leak determination.

[0013] In this refrigerant leakage detection method, by switching to one of a plurality of refrigerant leakage determinations based on whether the first operating data is normal or not, it is possible to detect a refrigerant leakage even if the first operating data is abnormal.

[0014] A refrigeration cycle apparatus according to a sixth aspect is a refrigeration cycle apparatus having a refrigerant circuit through which a refrigerant circulates. The refrigeration cycle apparatus includes a data acquisition unit and a control unit. The data acquisition unit acquires first operating data and second operating data of the refrigeration cycle apparatus. The control unit performs a first refrigerant leak determination using the first operating data or a second refrigerant leak determination using the second operating data. When the priority of the first refrigerant leak determination is higher than the priority of the second refrigerant leak determination, the control unit switches between the first refrigerant leak determination and the second refrigerant leak determination based on whether the first operating data is normal.

[0015] In this refrigeration cycle device, by switching to one of a plurality of refrigerant leakage determination methods based on whether the first operating data is normal or not, it is possible to detect a refrigerant leakage even if the first operating data is abnormal. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 is a functional block diagram of the refrigerant leak detection system. [Figure 2] FIG. 1 is a schematic diagram of a chilled water chiller. [Figure 3]FIG. 1 is a diagram illustrating an example of a combination of a main index and a sub-index. [Figure 4] FIG. 1 is a diagram illustrating an overview of leak detection. [Figure 5A] FIG. 10 is a diagram for explaining a refrigerant amount index. [Figure 5B] FIG. 10 is a diagram for explaining a refrigerant amount index. [Figure 6] 10 is a flowchart illustrating an example of a process performed by an index switching unit. [Figure 7] FIG. 10 is a diagram illustrating an example of a sensor abnormality. [Figure 8A] FIG. 1 is a diagram illustrating a conventional refrigerant leak detection system. [Figure 8B] FIG. 1 is a diagram illustrating a conventional refrigerant leak detection system. [Figure 9] FIG. 1 is a schematic diagram of a refrigeration cycle device. [Figure 10] FIG. 10 is a diagram for explaining detection of refrigerant leakage using only an index. [Figure 11] FIG. 10 is a diagram showing an example of a combination of main indexes and sub-indexes when the refrigeration cycle device does not have an economizer circuit. [Figure 12] FIG. 10 is a diagram showing an example of a combination of main indexes and sub-indexes when the refrigeration cycle device has an economizer circuit. [Figure 13] FIG. 4 is a diagram for explaining the flow of refrigerant leakage detection. [Figure 14] FIG. 10 is a diagram for explaining calculation of an abnormality degree. [Figure 15] FIG. 10 is a diagram illustrating an example of a combination of a main index and a sub-index. [Figure 16] FIG. 1 is a schematic diagram of an air conditioning device. DETAILED DESCRIPTION OF THE INVENTION

[0017] (1) Overall structure The refrigerant leak detection system 1 determines whether or not a refrigerant leak has occurred by using operating data of a refrigeration cycle device. FIG. 1 is a functional block diagram of the refrigerant leak detection system 1. The refrigerant leak detection system 1 mainly includes a refrigeration cycle device (chilled water chiller) 10 and a detection device 100. The refrigeration cycle device 10 and the detection device 100 are connected via a network 90. ​​The refrigerant leak detection system 1 detects a refrigerant leak in the refrigeration cycle device 10 by using the detection device 100.

[0018] (2) Detailed configuration (2-1) Refrigeration cycle equipment A refrigeration cycle device is a device that cools or heats an object using a vapor compression refrigeration cycle. Here, the refrigeration cycle device will be described using a chilled water chiller 10 as an example. Figure 2 is a schematic diagram of the chilled water chiller 10.

[0019] The chilled water chiller 10 is a device that cools a liquid by exchanging heat between water (a heat medium) and a refrigerant. The liquid cooled by the chilled water chiller 10 is supplied to a user device (not shown) and is used to cool the facility equipment. In this embodiment, water is used as the liquid (heat medium).

[0020] The chilled water chiller 10 includes a refrigerant circuit 50. The equipment arranged in the refrigerant circuit 50 mainly includes a compressor 21, a condenser 22, an expansion valve 23, an evaporator 24, and a fan 25. The refrigerant circuit 50 is configured by connecting the compressor 21, the condenser 22, the expansion valve 23, and the evaporator 24 by refrigerant piping as follows: The discharge port of the compressor 21 is connected to the inlet of the condenser 22 by refrigerant piping. The outlet of the condenser 22 is connected to the inlet of the evaporator 24 by refrigerant piping. The expansion valve 23 is arranged in the refrigerant piping that connects the outlet of the condenser 22 and the inlet of the evaporator 24. The outlet of the evaporator 24 is connected to the suction port of the compressor 21.

[0021] The fan 25 generates an airflow that causes air to pass through the condenser 22 in order to promote heat exchange between the refrigerant and the air in the condenser 22. The fan 25 is, for example, a propeller fan.

[0022] The equipment arranged in the refrigerant circuit 50 is not limited to the compressor 21, the condenser 22, the expansion valve 23, the evaporator 24, and the fan 25, and may include other equipment that is generally used in the refrigerant circuit 50 of a refrigeration cycle device.

[0023] The chilled water chiller 10 also includes a control unit 60 that controls the operation of each part of the chilled water chiller 10, such as the compressor 21 and the expansion valve 23.

[0024] When the chilled water chiller 10 is operated, refrigerant circulates within the refrigerant circuit 50 to perform a refrigeration cycle. Specifically, when the motor of the compressor 21 is operated, the compressor 21 draws in low-pressure gas refrigerant in the refrigeration cycle, compresses the drawn gas refrigerant, and discharges it as high-pressure gas refrigerant in the refrigeration cycle. The high-pressure gas refrigerant discharged from the compressor 21 is sent to the condenser 22. The high-pressure gas refrigerant sent to the condenser 22 releases heat and condenses in the condenser 22 to become high-pressure liquid refrigerant. The refrigerant condensed in the condenser 22 passes through the expansion valve 23 and is sent to the evaporator 24. The high-pressure liquid refrigerant flowing from the condenser 22 toward the evaporator 24 is reduced in pressure as it passes through the expansion valve 30, becoming a low-pressure two-phase gas-liquid refrigerant. The low-pressure two-phase gas-liquid refrigerant that flows into the evaporator 24 absorbs heat from the water (heat medium) supplied to the evaporator 24 and evaporates to become a low-pressure gas refrigerant. The refrigerant absorbs heat from the liquid in the evaporator 24, thereby cooling the liquid. The liquid cooled in the evaporator 24 is supplied to a user device (not shown) that uses the cooled liquid. Meanwhile, the gas refrigerant evaporated in the evaporator 24 is sucked into the compressor 21 and compressed again.

[0025] (2-1-1) Acquisition department The data acquisition unit of the refrigerant leak detection system 1 is made up of an acquisition unit of the chilled water chiller 10 and an input unit 110 of the detection device 100.

[0026] Various sensors (acquisition units) are provided in the chilled water chiller 10. Specifically, a compressor discharge pipe temperature sensor 31, a high-pressure side heat exchanger inlet gas pipe temperature sensor 32, a high-pressure side heat exchanger outlet liquid pipe temperature sensor 33, a low-pressure side heat exchanger liquid pipe temperature sensor 34, a supply water temperature sensor 35, a return water temperature sensor 36, a compressor suction pipe temperature sensor 37, a high-pressure side heat exchanger inlet pressure sensor 38, and an outside air temperature sensor 39 are provided.

[0027] The compressor discharge pipe temperature sensor (discharge temperature sensor) 31 detects the discharge temperature of the compressor 21. The high-pressure side heat exchanger inlet gas pipe temperature sensor (condenser inlet temperature sensor) 32 detects the temperature of the refrigerant at the gas side end of the condenser 22. The high-pressure side heat exchanger outlet liquid pipe temperature sensor (condenser outlet temperature sensor) 33 detects the temperature of the refrigerant at the liquid side end of the condenser 22. The low-pressure side heat exchanger temperature sensor (evaporator inlet temperature sensor) 34 detects the temperature of the refrigerant flowing through the evaporator 24. The supply water temperature sensor 35 detects the temperature of water sent from the evaporator 24 to the user-side equipment. The return water temperature sensor 36 detects the temperature of water returning from the user-side equipment to the evaporator 24. The compressor suction pipe temperature sensor 37 detects the suction temperature of the compressor 21. The high-pressure side heat exchanger inlet pressure sensor 38 detects the pressure at the gas side end of the condenser 22. The outside air temperature sensor 39 detects the temperature of outdoor air (outdoor temperature).

[0028] (2-1-2) Control Unit The control unit 60 is connected so as to be able to receive detection signals from various sensors 31, 32, 33, 34, 35, 36, 37, 38, and 39 that the chilled water chiller 10 has. The control unit 60 also controls the compressor 21 and the expansion valve 23 based on these detection signals. The control unit 60 also calculates operating data from the detection signals (detection values) of the various sensors 31, 32, 33, 34, 35, 36, 37, 38, and 39.

[0029] (2-2) Detection device The detection device 100 of this embodiment is a computer installed on the cloud. The detection device 100 may be installed, for example, inside the chilled water chiller 10. The detection device 100 has an input unit 110 and a control unit 120.

[0030] (2-2-1) Input section Operational data of chilled water chiller 10 is input to input unit 110. The operational data of chilled water chiller 10 includes first operational data and second operational data different from the first operational data. The operational data input to input unit 110 includes detected values ​​of various sensors 31, 32, 33, 34, 35, 36, 37, 38, and 39 possessed by chilled water chiller 10 and values ​​calculated from the detected values ​​of various sensors 31, 32, 33, 34, 35, 36, 37, 38, and 39 possessed by chilled water chiller 10.

[0031] The operating data of the chilled water chiller 10 includes the degree of subcooling (SC), circuit number, number of compressors, intake superheat, intake superheat (set value), discharge superheat, fan rotation speed, supply water temperature, supply water temperature (set value), return water temperature, evaporation temperature, condensation temperature, compressor load (rate), total compressor load (rate), outside air temperature, expansion valve opening, and approach temperature.

[0032] In this embodiment, the condensation temperature is the value of the high-pressure side heat exchanger inlet gas pipe temperature sensor 32. The condensation temperature is not limited to the value of the high-pressure side heat exchanger inlet gas pipe temperature sensor 32. If the high-pressure side heat exchanger inlet gas pipe temperature sensor 32 is not provided, the pressure value detected by the high-pressure side heat exchanger inlet pressure sensor 38 may be converted to temperature to obtain the condensation temperature.

[0033] The degree of subcooling (SC) is calculated from the difference between the condensing temperature and the value of the high-pressure side heat exchanger outlet liquid pipe temperature sensor 33. The value equivalent to the degree of subcooling includes the difference between the physical property values, such as entropy and enthalpy, of the refrigerant in a saturated state in the condenser 22 and the refrigerant at the condenser outlet, as well as values ​​obtained by compensating the difference in the degree of subcooling and the physical property values ​​with the difference in other state quantities.

[0034] The suction superheat degree is calculated from the difference between the value of compressor suction pipe temperature sensor 37 and the evaporating temperature. The discharge superheat degree is calculated from the difference between the value of compressor discharge pipe temperature sensor 31 and the condensing temperature. The supply water temperature is the value of supply water temperature sensor 35. The return water temperature is the value of return water temperature sensor 36. The evaporating temperature is the value of low-pressure side heat exchanger temperature sensor 34. The outside air temperature is the value of outside air temperature sensor 39. The expansion valve opening is calculated from the suction superheat degree or the discharge superheat degree. The approach temperature is calculated from the difference between the evaporating temperature and the supply water temperature.

[0035] (2-2-2) Control Unit The control unit 120 is realized by a computer. The control unit 120 includes a control and arithmetic unit and a storage device (not shown). A processor such as a CPU or a GPU can be used as the control and arithmetic unit. The control and arithmetic unit reads a program stored in the storage device and performs predetermined image processing and arithmetic processing in accordance with the program. Furthermore, the control and arithmetic unit can write the results of calculations to the storage device and read information stored in the storage device in accordance with the program. The storage device can be used as a database.

[0036] The control unit 120 performs a first refrigerant leakage determination using the first operating data or a second refrigerant leakage determination using the second operating data. The control unit 120 switches between the first refrigerant leakage determination and the second refrigerant leakage determination based on whether the first operating data is normal or not.

[0037] In the refrigerant leak detection system 1, for example, the input unit 110 acquires a degree of subcooling (first operating data) calculated from the detection values ​​of the high-pressure side heat exchanger inlet gas pipe temperature sensor 32 and the high-pressure side heat exchanger outlet liquid pipe temperature sensor 33. The input unit 110 also acquires an expansion valve opening (second operating data) calculated using the discharge degree of superheat obtained from the compressor discharge pipe temperature sensor 31. When the priority of the refrigerant leak determination using the subcooling degree is higher than the priority of the refrigerant leak determination using the expansion valve opening, the control unit 120 switches between the refrigerant leak determination using the subcooling degree and the refrigerant leak determination using the expansion valve opening based on whether the subcooling degree is normal. In other words, the control unit 120 selects the first refrigerant leak determination using the subcooling degree when the priority of the refrigerant leak determination using the subcooling degree (first refrigerant leak determination) is higher than the priority of the refrigerant leak determination using the expansion valve opening (second refrigerant leak determination) and the subcooling degree is normal. Furthermore, when the priority of the first refrigerant leakage determination is higher than the priority of the second refrigerant leakage determination and the degree of subcooling is abnormal, the control unit 120 selects the second refrigerant leakage determination using the expansion valve opening degree.

[0038] The control unit 120 uses, as operating data, for example, a predicted value of the degree of subcooling, a predicted value of the degree of discharge superheat, or a predicted value of the expansion valve opening, which are determined by a normal prediction model (hereinafter also referred to as a prediction model or a correction model) 161 created from operating data when the operating data is normal.

[0039] The control unit 120 includes a confirmation unit 130 , an index holding unit 140 , an index switching unit 150 , a calculation unit, and a determination unit 170 .

[0040] (2-2-3) Verification Section The confirmation unit 130 confirms whether the values ​​of the variables, which are the indicators 141 for determining whether a refrigerant leak has occurred in the chilled water chiller 10, are normal. Variables 141 include sensor values ​​and command values. The sensor values ​​are actual measured values ​​of various sensors 31, 32, 33, 34, 35, 36, 37, 38, and 39 that chilled water chiller 10 has. The command value is a value that indicates whether or not operating data has been acquired when chilled water chiller 10 is instructed to acquire the data. For example, if operating data cannot be acquired due to a communication error or the like, the command value is determined to be abnormal.

[0041] The detection method uses one of the following methods.

[0042] In rule-based detection, abnormalities are detected based on predefined thresholds or specific patterns from error codes or actual measured values ​​from sensors or indication values.

[0043] Statistical methods use statistical models such as probability distributions, Mahalanobis distance, Hotelling's theory, and k-nearest neighbor methods to detect anomalies.

[0044] Supervised learning-based methods use labeled datasets to train models and detect anomalies in predicted values. Supervised learning-based methods use classifiers or regression models.

[0045] In unsupervised learning-based methods, a model is trained using unlabeled data and anomalies are detected from the prediction results. Examples of unsupervised learning-based methods include clustering and principal component analysis.

[0046] Deep learning-based techniques use neural networks to extract features from big data and detect anomalies.

[0047] (2-2-4) Index holding part The index storage unit 140 stores indexes 141 for determining refrigerant leakage from the chilled water chiller 10. The indexes 141 include a main index and sub-indices. The index with priority 1 is the index with the highest priority and is the main index. The index with priority 2 has a lower priority than the index with priority 1 and is a sub-indicator. The index with priority 3 has a lower priority than the indexes with priorities 1 and 2 and is a sub-indicator. The smaller the number indicating the order of priority, the higher the priority.

[0048] FIG. 3 is a diagram showing an example of a combination of main indicators and sub-indicators in the refrigerant leak detection system 1. As shown in FIG.

[0049] As shown in FIG. 3, the main index (objective variable) of priority 1 is the degree of supercooling.

[0050] Furthermore, at priority level 1, the following operational data is used as explanatory variables: circuit number, number of compressors, suction superheat, suction superheat (set value), discharge superheat, fan speed, supply water temperature, supply water temperature (set value), return water temperature, evaporation temperature, condensation temperature, compressor load (rate), overall compressor load (rate), outside air temperature, expansion valve opening, and approach temperature. Note that if the refrigeration cycle device has an economizer circuit (see FIG. 9), either the economizer expansion valve opening or the economizer superheat may also be used as explanatory variables.

[0051] The sub-indicator (objective variable) for Priority 2 is the expansion valve opening. Furthermore, the explanatory variables for Priority 2 are parameters obtained by excluding the objective variable from the main explanatory variables. Specifically, for Priority 2, the operating data used as explanatory variables is the degree of subcooling, which is the objective variable for Priority 1, and the expansion valve opening, which is the objective variable for Priority 2.

[0052] The sub-index (objective variable) for priority 3 is the degree of discharge superheat. The explanatory variables for priority 3 are parameters obtained by excluding the objective variable from the main explanatory variables. Specifically, for priority 3, the explanatory variables used are the operating data excluding the degree of subcooling, the expansion valve opening, and the degree of discharge superheat, which are the objective variables for priorities 1 to 3.

[0053] Note that the objective variables and explanatory variables in the main index and sub-index are not limited to these.

[0054] (2-2-5) Index switching section The index switching unit 150 has an index priority sheet 151. The index switching unit 150 switches the index used for refrigerant leakage determination.

[0055] The priority of the index 141 in the refrigerant leak detection system 1 of this embodiment is determined based on an evaluation index. The evaluation indexes used are a correlation coefficient with the refrigerant amount, a t-value, a correct answer rate, an incorrect answer rate, a precision rate, a recall rate, and an F-value. When machine learning is used, MAE, MAPE, MSE, RMSE, a coefficient of determination, etc. may also be used as the evaluation index.

[0056] The main indicators A, B, and C for Priority 1 have an evaluation index of 0.9. The sub-indicators B and C for Priority 2 have an evaluation index of 0.8, which is smaller than the main indicator for Priority 1. The sub-indicators C and D for Priority 3 have an evaluation index of 0.5, which is smaller than the main indicator for Priority 1 and the sub-indicators for Priority 2.

[0057] For example, when the variable of indicator A used as the main indicator is abnormal, the indicator switching unit 150 selects the sub-indicator with the next highest priority, priority 2, from among the sub-indicators that do not use indicator A.

[0058] (2-2-6) Arithmetic section Calculation unit 160 has a normal prediction model (correction model) 161. Calculation unit 160 calculates a refrigerant amount index predicted value using normal prediction model 161. Calculation unit 160 calculates a Δ refrigerant amount index, which is the degree of deviation between the refrigerant amount index predicted value and the refrigerant amount index actual measurement value.

[0059] The refrigerant leak detection system 1 uses an index related to the amount of refrigerant as a refrigerant amount index, and creates a normal prediction model 161 by machine learning from operating data during normal times.

[0060] The explanatory variables of the normal prediction model 161 are actual measured values ​​of the operating data other than the refrigerant amount index. The dependent variable is the actual measured value of the refrigerant amount index. For example, if the refrigerant amount index is the degree of subcooling, the explanatory variables are actual measured values ​​of the operating data other than the degree of subcooling, and the dependent variable is the actual measured value of the degree of subcooling.

[0061] FIG. 4 is a diagram showing an overview of leak detection in the refrigerant leak detection system 1. As shown in FIG.

[0062] Verification data (operation data) is acquired as shown in Fig. 4. The verification data includes the actual measurement value of the refrigerant amount index and the actual measurement value of the operation data other than the refrigerant amount index used as the response variable.

[0063] Calculation unit 160 calculates a refrigerant amount index predicted value from the verification data using normal prediction model 161. Calculation unit 160 also calculates a Δ refrigerant amount index, which is the degree of deviation between the refrigerant amount index predicted value and the refrigerant amount index actual measurement value. Determination unit 170 determines whether a refrigerant leak exists using the Δ refrigerant amount index.

[0064] (2-2-7) Judgment section The determination unit 170 uses the Δ refrigerant amount index calculated by the calculation unit 160 to determine whether or not there is a refrigerant leak.

[0065] 5A and 5B are diagrams illustrating the refrigerant amount index in the refrigerant leak detection system 1 of this embodiment. As shown in FIG. 5A, when a refrigerant leak occurs, a Δ refrigerant amount index is generated, which is the difference between the predicted value of the refrigerant amount index and the actual measured value of the refrigerant amount index. The magnitude of the Δ refrigerant amount index increases as time passes after the refrigerant leak. As shown in FIG. 5B, when the Δ refrigerant amount index decreases and exceeds a threshold value for a certain period of time, the determination unit 170 determines that a refrigerant leak has occurred.

[0066] (3) Processing An example of the processing of the index switching unit 150 in the refrigerant leak detection system 1 will be described with reference to the flowchart of FIG.

[0067] In step S1, operation data is acquired for the chilled water chiller 10. In this embodiment, for example, the operation data is acquired by acquiring the value (condensation temperature) of the high-pressure side heat exchanger inlet gas pipe temperature sensor 32 and the value of the high-pressure side heat exchanger outlet liquid pipe temperature sensor 33 in order to calculate the degree of subcooling.

[0068] In step S2, each variable is checked for abnormalities. Each variable includes a sensor value and a command value. In this embodiment, the variables are sensor values. For example, it is checked whether the value (condensation temperature) of the high-pressure side heat exchanger inlet gas pipe temperature sensor 32 and the value of the high-pressure side heat exchanger outlet liquid pipe temperature sensor 33, which were acquired to calculate the degree of subcooling, are abnormal. The variables may also be command values. For example, if operating data cannot be acquired due to a communication abnormality or the like, it is determined that the command value is abnormal.

[0069] In step S3, the priority of the index used in refrigerant leakage determination is designated. In this embodiment, the priority is designated as "1" (priority=1).

[0070] In step S4, it is determined whether the numerical value indicating the order of priority is equal to or less than "N", which is the number of indices. If the numerical value indicating the order of priority is equal to or less than "N" (Yes in step S4), the process proceeds to step S5. In this embodiment, the number of indices is "8". Since the priority is "1", which is smaller than the number of indices, "8", the process proceeds to step S5.

[0071] In step S5, it is determined whether the index of the designated priority is normal. In this embodiment, it is determined whether the degree of supercooling, which is the index of priority 1, is normal.

[0072] If the degree of subcooling is normal (Yes in step S5), the process proceeds to step S6. In step S6, an index of the designated priority is selected. In this embodiment, the index switching unit 150 selects the index of priority 1 (degree of subcooling).

[0073] If the degree of subcooling is not normal (No in step S5), proceed to step S7. In step S7, the priority of the index used to determine refrigerant leakage is changed to the next priority. In this embodiment, the priority of the index used to determine refrigerant leakage is changed from priority 1 to priority 2. For example, the index with priority 2 is the expansion valve opening.

[0074] If the priority is greater than "N" which is the number of indexes (No in step S4), the process proceeds to step S8. In step S8, refrigerant leakage detection based on the indexes is not performed.

[0075] In the refrigerant leak detection system 1, the sub-indicator is used as a substitute for the main indicator, thereby reducing the risk of false detection or overlooking a leak caused by abnormal values ​​due to sensor failure or missing data due to communication abnormalities.

[0076] An example of a sensor abnormality is shown in Figure 7. As shown in Figure 7, the main index is an index that uses index A obtained from sensor A, and the sub-index is an index that uses values ​​that can be obtained from sensors other than sensor A. When an abnormality is detected in sensor A, sensor A will take a value lower than it should due to the sensor abnormality, resulting in a false detection. Therefore, during the period when sensor A is out of order, false detection is prevented by substituting an index that uses a value other than sensor A. After sensor A is repaired, if the sensor value of sensor A returns to a normal value, it will switch to the main index. When sensor A used in the main index fails, false detection is prevented by switching to the sub-indicator.

[0077] (4) Features (4-1) The refrigerant leak detection system 1 according to this embodiment includes a chilled water chiller 10 and an input unit 110. The chilled water chiller 10 has a refrigerant circuit 50 through which refrigerant circulates. The input unit 110 acquires the degree of subcooling and the expansion valve opening from the chilled water chiller 10. The control unit 120 performs a refrigerant leak determination using the degree of subcooling or a refrigerant leak determination using the expansion valve opening. When the priority of the refrigerant leak determination using the degree of subcooling is higher than the priority of the refrigerant leak determination using the expansion valve opening, the control unit 120 switches between the refrigerant leak determination using the degree of subcooling and the refrigerant leak determination using the expansion valve opening based on whether the degree of subcooling is normal.

[0078] Conventionally, there are models that use operational data acquired from sensors installed in the equipment to predict the operating state of the equipment, and systems exist that use the predicted results to detect refrigerant leaks. However, in conventional refrigerant leak detection systems, if a malfunction occurs in the sensor used to detect refrigerant leaks, the sensor value may differ from normal, resulting in a false detection. Furthermore, if the operational data parameters used for prediction cannot be obtained due to communication abnormalities or other reasons, the operating state of the equipment cannot be predicted, and leaks cannot be detected. As such, conventional refrigerant leak detection systems are at risk of false detection or overlooking leaks due to abnormal values ​​caused by sensor malfunctions or missing data due to communication abnormalities.

[0079] 8A and 8B are diagrams for explaining a conventional refrigerant leakage detection system.

[0080] As shown in Figure 8A, when a sensor malfunctions, the degree of subcooling may be lower than normal, resulting in a false detection of a refrigerant leak. Also, as shown in Figure 8B, when a communication error occurs, the actual measured value of the degree of subcooling may not be obtained due to the communication error, and a refrigerant leak may be overlooked.

[0081] The refrigerant leak detection system 1 according to this embodiment is provided with a main index and one or more sub-indicators used to predict the operating state of the equipment, and an index switching unit 150 that automatically switches the index used to predict the operating state of the equipment based on the acquired operating data. An index is selected from preset indices based on the "priority" of the index. The variable used for the most important index (main) is checked to see if it is normal, and if the value is normal, the main is selected. If the variable used for the index is abnormal, the same procedure is repeated from the sub-indicators in order of importance until an index is selected.

[0082] In this refrigerant leak detection system 1, by switching between refrigerant leak determination using the degree of subcooling and refrigerant leak determination using the expansion valve opening degree based on whether the degree of subcooling is normal or not, it is possible to detect refrigerant leaks even if the degree of subcooling is abnormal.

[0083] (4-2) In the refrigerant leak detection system 1 according to this embodiment, the control unit 120 selects the refrigerant leak determination using the degree of subcooling when the degree of subcooling is normal, and the control unit 120 selects the refrigerant leak determination using the expansion valve opening degree when the degree of subcooling is abnormal.

[0084] In this refrigerant leakage detection system 1, by selecting the refrigerant leakage determination using the expansion valve opening when the degree of subcooling is abnormal, it is possible to detect a refrigerant leakage even if the degree of subcooling is abnormal.

[0085] (4-3) In the refrigerant leak detection system 1 according to this embodiment, the control unit 120 uses, as the first operating data and the second operating data, a predicted value of the degree of subcooling, a predicted value of the discharge superheat, or a predicted value of the expansion valve opening, which are determined by a prediction model 161 created from operating data when the operating data is normal.

[0086] In this refrigerant leak detection system 1, a refrigerant leak can be detected using a predicted value of the degree of subcooling, a predicted value of the discharge superheat, or a predicted value of the expansion valve opening as the first operating data and the second operating data.

[0087] (4-4) The refrigerant leak detection system 1 of this embodiment includes at least one of a high-pressure side heat exchanger inlet gas pipe temperature sensor (condenser inlet temperature sensor) 32, a high-pressure side heat exchanger outlet liquid pipe temperature sensor (condenser outlet temperature sensor) 33, and a compressor discharge pipe temperature sensor (discharge temperature sensor) 31 as a data acquisition unit.

[0088] In this refrigerant leakage detection system 1, the degree of supercooling, the degree of discharge superheat, or the degree of expansion valve opening can be acquired as the operating data.

[0089] (4-5) The refrigerant leak detection method using the refrigerant leak detection system 1 according to this embodiment includes a data acquisition step and a control step. The data acquisition step acquires the degree of subcooling and the expansion valve opening from a chilled water chiller 10 having a refrigerant circuit 50 through which refrigerant circulates. The control step performs a refrigerant leak determination using the degree of subcooling or a refrigerant leak determination using the expansion valve opening. The control step switches between refrigerant leak determination using the degree of subcooling and refrigerant leak determination using the expansion valve opening based on whether the degree of subcooling is normal when the priority of refrigerant leak determination using the degree of subcooling is higher than the priority of refrigerant leak determination using the expansion valve opening.

[0090] In this refrigerant leakage detection method, by switching between refrigerant leakage determination using the degree of subcooling and refrigerant leakage determination using the expansion valve opening degree based on whether the degree of subcooling is normal or not, it is possible to detect refrigerant leakage even if the degree of subcooling is abnormal.

[0091] (5) Variations (5-1) Variation 1A In this embodiment, the case where the degree of supercooling has priority 1 has been described, but the present invention is not limited to this.

[0092] The main indicator (objective variable) for priority 1 may be the expansion valve opening, the sub-indicator (objective variable) for priority 2 may be the sub-indicator (objective variable) for priority 3 may be the discharge superheat. When the expansion valve opening is priority 1, the explanatory variables used may be any or all of the following operating data: circuit number, number of compressors, suction superheat, suction superheat (set value), discharge superheat, fan speed, supply water temperature, supply water temperature (set value), return water temperature, evaporation temperature, condensation temperature, compressor load (rate), total compressor load (rate), outside air temperature, subcooling, and approach temperature. When the subcooling rate is priority 2, the explanatory variables used for priority 2 are the expansion valve opening, which is the objective variable for priority 1, and the operating data excluding the subcooling rate, which is the objective variable for priority 2. When priority 3 is the degree of discharge superheat, the operating data used for priority 3 is the explanatory variables excluding the expansion valve opening, the degree of subcooling, and the degree of discharge superheat, which are the objective variables for priorities 1 to 3.

[0093] (5-2) Variation 1B The refrigeration cycle device of the refrigerant leak detection system 1 may include an economizer circuit.

[0094] 9 is a schematic configuration diagram of the refrigeration cycle apparatus 11. In Modification 1B, the refrigeration cycle apparatus 11 is a chilled water chiller. The configuration of the refrigeration cycle apparatus 11, other than the economizer circuit, is the same as that of the refrigeration cycle apparatus (chilled water chiller) 10 of this embodiment, and therefore detailed description thereof will be omitted.

[0095] The chilled water chiller 11 includes a refrigerant circuit 51. The devices arranged in the refrigerant circuit 51 mainly include a compressor 21, a condenser 22, an expansion valve 23, and an evaporator 24. The chilled water chiller 11 also includes an economizer circuit 80. The economizer circuit 80 mainly includes an economizer heat exchanger 26 and an economizer expansion valve 27.

[0096] The compressor 21, condenser 22, expansion valve 23, evaporator 24, and various sensors 31, 32, 33, 34, 35, 36, 37, 38, and 39 are the same as those in the chilled water chiller 10 of this embodiment shown in FIG. 2, and therefore detailed description thereof will be omitted.

[0097] In the compressor 21, intermediate injection is performed in which a portion of the intermediate-pressure refrigerant flowing from the condenser 22 toward the expansion valve 23 is supplied to the compressor 21 compressing the refrigerant. The intermediate pressure is a predetermined pressure between the pressure (low pressure) of the gas refrigerant sucked into the compressor 21 and the pressure (high pressure) of the gas refrigerant discharged from the compressor 21.

[0098] The economizer heat exchanger 26 is disposed between the condenser 22 and the expansion valve 23. The economizer heat exchanger 26 exchanges heat between the refrigerant flowing from the condenser 22 toward the expansion valve 23 and the refrigerant flowing through the economizer pipe 28. The economizer pipe 28 is a pipe that branches off from between the economizer heat exchanger 26 and the expansion valve 23 in the refrigerant circuit 51 and is connected to the injection pipe 29. An economizer expansion valve 27 is attached to the economizer pipe 28. The refrigerant flowing through the economizer pipe 28 is decompressed by the economizer expansion valve 27, and then exchanges heat with the refrigerant flowing from the condenser 22 toward the expansion valve 23 in the economizer heat exchanger 26. The refrigerant that has exchanged heat with the refrigerant flowing from the condenser 22 toward the expansion valve 23 in the economizer heat exchanger 26 is supplied to the injection pipe 29 as intermediate-pressure refrigerant.

[0099] In variant example 1B, in determining whether a refrigerant leaks in a refrigeration cycle device 11 having an economizer circuit 80, the refrigerant leak can be determined using the economizer expansion valve opening degree and the economizer superheat degree in addition to the suction superheat degree as explanatory variables of the correction model 161.

[0100] (5-3) Variation 1C A single index or a combination of multiple indexes related to the amount of refrigerant may be used as the refrigerant amount index, and refrigerant leakage may be detected from changes in the value.

[0101] Fig. 10 is a diagram for explaining detection of a refrigerant leak using only an index. As shown in Fig. 10, when the refrigerant amount index is the degree of supercooling (SC), the degree of supercooling decreases during a refrigerant leak, and if the degree of supercooling exceeds a certain range for a certain period of time, it is determined that a refrigerant leak has occurred. FIG. 11 is a diagram showing an example of a combination of main indexes and sub-indexes when the refrigeration cycle device does not have an economizer circuit (see FIG. 2).

[0102] An example of using the degree of supercooling as the main index is shown below. In this case, the value of the degree of supercooling is not used as the sub-index.

[0103] The order of priority varies depending on the target model, operation mode, etc., and is not limited to the example shown in FIG.

[0104] The main index with priority 1 is an index that uses at least the degree of subcooling (for example, an index that uses the degree of subcooling, evaporation temperature, or condensation temperature).

[0105] Sub-indicators with a second priority are indices that use at least the expansion valve opening (for example, indices that use values ​​related to the main expansion valve opening, the discharge superheat degree, and the refrigerant circulation amount).

[0106] Sub-indicators with a priority of 3 are indices that use at least the compressor load factor or the rotation speed (for example, indices that use the compressor load factor, the main expansion valve opening, or the degree of suction superheat).

[0107] Fig. 12 is a diagram showing an example of a combination of main indexes and sub-indexes when the refrigeration cycle device has an economizer circuit (see Fig. 9). The order of priority varies depending on the target model, operation mode, etc., and is not limited to the example shown in Fig. 12.

[0108] The main index with priority 1 is an index that uses at least the degree of subcooling (for example, an index that uses the degree of subcooling, evaporation temperature, or condensation temperature).

[0109] Sub-indicators with priority 2 are indices that use at least the economizer expansion valve opening (for example, indices that use values ​​related to the economizer expansion valve opening, the main expansion valve (expansion valve) opening, the discharge superheat, and the refrigerant circulation amount).

[0110] Sub-indicators with priority 3 are indicators that use at least the economizer superheat degree (for example, indicators that use values ​​related to the economizer superheat degree, main expansion valve opening, economizer expansion valve opening, suction superheat degree, and refrigerant circulation amount).

[0111] In Modification 1C, a single index or a combination of multiple indexes related to the amount of refrigerant is used as the refrigerant amount index, and refrigerant leakage is detected from changes in the value, making it possible to easily determine whether or not a refrigerant leak has occurred.

[0112] (5-4) Variation 1D A binary classification model may be created using machine learning from normal data and abnormal data, and refrigerant leaks may be detected based on the results of the binary classification model.

[0113] A binary classification model is created using normal and leak data. The explanatory variables are actual measurements of refrigerant usage related to the amount of refrigerant. The response variable is either "0" for normal or "1" for leak.

[0114] FIG. 13 is a diagram for explaining the flow of refrigerant leak detection. The calculation unit 160 has a classification model (binary classification model). As shown in FIG. 13, verification data (operation data) is input to the classification model. The calculation unit 160 outputs a normal / leak label from the classification model and calculates the degree of abnormality. The determination unit 170 determines whether there is a refrigerant leak based on the degree of abnormality.

[0115] 14A and 14B are diagrams for explaining how to calculate the degree of abnormality. As shown in Fig. 14A and 14B, the proportion of times determined to be a leak within the window frame is calculated as the degree of abnormality.

[0116] Fig. 15 is a diagram showing an example of a combination of main indexes and sub-indices in Modification 1 D. As shown in Fig. 15, the response variable is normality or leakage.

[0117] Furthermore, when the refrigeration cycle device does not have an economizer circuit (see FIG. 2), the main index of priority 1 uses any of the following operational data as explanatory variables: degree of subcooling, circuit number, number of compressors, degree of superheat, degree of superheat (set value), discharge degree of superheat, fan rotation speed, supply water temperature, supply water temperature (set value), return water temperature, evaporation temperature, condensation temperature, compressor load (rate), total compressor load (rate), outside air temperature, expansion valve opening, and approach temperature. For example, in modification 1D, the degree of subcooling is used as the explanatory variable of priority 1.

[0118] For the sub-indicators with priority 2, the operating data excluding the degree of subcooling used as the explanatory variable for the main index is used as the explanatory variable.

[0119] When the refrigeration cycle device has an economizer circuit (see FIG. 9), either the economizer expansion valve opening degree or the economizer superheat degree may be further used as an explanatory variable.

[0120] In variant 1D, a binary classification model is created using machine learning from normal data and abnormal data, and refrigerant leaks are detected from the results of the binary classification model, making it possible to easily determine whether a refrigerant leak has occurred.

[0121] (5-5) Variation 1E The control unit 120 may use a predicted value of the degree of subcooling or a predicted value of the degree of discharge superheat determined by an arithmetic expression as the first operating data and the second operating data. The first operating data and the second operating data are not limited to the predicted value of the degree of subcooling or the predicted value of the degree of discharge superheat.

[0122] For example, refrigerant leakage is detected using a predicted refrigerant value based on values ​​relating to the expansion valve opening, the refrigerant state quantity at the compressor inlet or outlet, and the refrigerant circulation amount.

[0123] If the refrigeration cycle device does not have an economizer circuit (see Figure 2), the expansion valve opening, the refrigerant state quantity at the compressor inlet or outlet, and a value related to the refrigerant circulation amount are input, and a value related to the refrigerant leakage amount (for example, the refrigeration air conditioning device refrigerant leakage amount (amount leaking) or the amount of refrigerant held (amount held)) is output using the following regression formula. The following is an example of a regression formula using the discharge superheat, but the same applies when y is the discharge temperature, suction superheat, or suction temperature. TIFF2026003345000002.tif787 Refrigerant amount prediction value: Refrigerant amount held in refrigeration and air conditioning equipment (amount held) x: Main expansion valve opening y: Compressor discharge superheat z: Value related to circulation volume ω k: weight parameter, l, m, n: integers between 0 and 3, l+m+n ≦ 3

[0124] The value related to the refrigerant circulation amount may be a value of operational data (e.g., load factor) that has a strong correlation with the refrigerant circulation amount, or may be a value of the refrigerant circulation amount (in other words, an actually measured value). For example, the value related to the refrigerant circulation amount is any of the load factors defined as the capacity of the refrigeration and air conditioning device or the ratio of that capacity to its maximum capacity, the compressor rotation speed or the ratio of that compressor rotation speed to its maximum rotation speed, the number of operating compressors or the ratio of the number of operating compressors to its maximum number of operating compressors, and the inverter frequency of the compressor motor.

[0125] If the refrigeration cycle device has an economizer circuit (see Figure 9), and the opening of the main expansion valve and the opening of the economizer control expansion valve are used, the refrigerant amount is predicted using the following formula: Note that if a refrigeration air conditioning device (refrigeration cycle device) with an economizer does not use an economizer, only the opening of the main expansion valve is used. TIFF2026003345000003.tif8123 Refrigerant amount prediction value: Refrigerant amount held in refrigeration and air conditioning equipment (amount held) x1: Main expansion valve opening x2: Opening degree of expansion valve for economizer control y: Compressor discharge superheat z: Value related to circulation volume ω k: weight parameter, l1, l2, m, n: integers between 0 and 4, l1+l2+m+n ≦ 4

[0126] In Modification 1E, refrigerant leakage detection can be performed using predicted refrigerant amount values ​​determined by an arithmetic expression as the first operating data and the second operating data.

[0127] (5-6) Variation 1F In the refrigerant leak detection system 1 of this embodiment, a case has been described in which the refrigeration cycle apparatus 10 is a chilled water chiller. The refrigeration cycle apparatus 10 is not limited to a chilled water chiller, and may be a multi-type air conditioner for a building having multiple indoor units, a hot water heater, or a cooling apparatus for a freezer or refrigerator.

[0128] 16 is a schematic configuration diagram of a refrigeration cycle apparatus 101. In Modification 1F, the refrigeration cycle apparatus 101 is a multi-type air conditioning apparatus for a building. The refrigeration cycle apparatus 101 mainly includes an outdoor unit 102 and multiple (here, two) indoor units 103a and 103b connected in parallel with each other.

[0129] The air conditioner 101 includes a refrigerant circuit 52 and an economizer circuit (subcooling circuit) 80. The equipment arranged in the refrigerant circuit 52 mainly includes a compressor 71, a four-way switching valve 72, an outdoor heat exchanger 73, an expansion valve 74, indoor expansion valves 75a and 75b, indoor heat exchangers 76a and 76b, and an accumulator 77. The economizer circuit 80 includes an economizer heat exchanger 26 and an economizer expansion valve 27. The economizer circuit 80 is the same as the chilled water chiller 11 of modification 1B shown in FIG. 9 , and therefore a detailed description thereof will be omitted.

[0130] The air conditioner 101 also includes a control unit 60 that controls the operation of each unit of the air conditioner 101, such as the compressor 71, expansion valve 74, and indoor expansion valves 75a and 75b. When the refrigeration cycle device is the air conditioner 101, the control unit 60 has an outdoor control unit 62 in the outdoor unit 200, and indoor control units 63a and 63b in the indoor units 103a and 103b.

[0131] Compressor 71 compresses low-pressure gas refrigerant to high-pressure gas refrigerant. In compressor 71, intermediate injection is performed in which a portion of the intermediate-pressure refrigerant that flows from outdoor heat exchanger 73 through expansion valve 74 is supplied via accumulator 77 to compressor 71, which is compressing the refrigerant.

[0132] The four-way switching valve 72 switches the flow of refrigerant between the broken line (heating) and the solid line (cooling) in FIG.

[0133] During heating operation, the refrigerant discharged from the compressor 71 passes through the indoor heat exchangers 76a and 76b, the indoor expansion valves 75a and 75b, the expansion valve 74, the outdoor heat exchanger 73, and the accumulator 77, and is then sucked back into the compressor 71. In other words, during heating, the indoor heat exchangers 76a and 76b function as condensers, and the outdoor heat exchanger 73 functions as an evaporator.

[0134] During cooling operation, the refrigerant discharged from the compressor 71 passes through the outdoor heat exchanger 73, the expansion valve 74, the indoor expansion valves 75a and 75b, the indoor heat exchangers 76a and 76b, and the accumulator 77, and is then sucked back into the compressor 71. In other words, during cooling, the outdoor heat exchanger 73 functions as a condenser, and the indoor heat exchangers 75a and 75b function as evaporators.

[0135] The air conditioner 100 is also provided with various sensors (acquisition units). Specifically, a compressor discharge pipe temperature sensor 31, a high-pressure side heat exchanger inlet gas pipe temperature sensor 32, a high-pressure side heat exchanger outlet liquid pipe temperature sensor 33, a high-pressure side heat exchanger inlet pressure sensor 38, a subcooling heat exchanger outlet gas pipe temperature sensor 81, and a subcooling heat exchanger outlet liquid pipe temperature sensor 82 are provided. Each of the sensors 31, 32, 33, and 38 is the same as that of the chilled water chiller 10 of this embodiment shown in FIG. 2, and therefore detailed description will be omitted. The subcooling heat exchanger outlet gas pipe temperature sensor 81 detects the temperature of the refrigerant at the gas side end of the economizer heat exchanger 26. The subcooling heat exchanger outlet liquid pipe temperature sensor 82 detects the temperature of the refrigerant at the liquid side end of the economizer heat exchanger 26.

[0136] When the refrigeration cycle device is a multi-type air conditioning device 100 for buildings, it is preferable to determine refrigerant leakage using, for example, the degree of supercooling as the main indicator with priority 1 during cooling operation, and the discharge superheat as the main indicator with priority 1 during heating operation.

[0137] (5-7) Variation 1G In the refrigerant leak detection system 1 of this embodiment, the detection device 100 detects a refrigerant leak in the refrigeration cycle apparatus (chilled water chiller) 10. However, the control unit 60 of the chilled water chiller 10 may also detect a refrigerant leak in the chilled water chiller 10. The control unit 60 performs a first refrigerant leak determination using the degree of subcooling or a second refrigerant leak determination using the expansion valve opening. When the priority of the refrigerant leak determination using the degree of subcooling is higher than the priority of the refrigerant leak determination using the expansion valve opening, the control unit 60 switches between the first refrigerant leak determination and the second refrigerant leak determination based on whether the degree of subcooling is normal. In this way, by switching between the first refrigerant leak determination using the degree of subcooling and the second refrigerant leak determination using the expansion valve opening based on whether the degree of subcooling is normal, a refrigerant leak can be detected even if the degree of subcooling is abnormal.

[0138] (5-8) Although the embodiments of the present disclosure have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the present disclosure as defined in the claims. [Explanation of symbols]

[0139] 1. Refrigerant leak detection system 10, 11 Chilled water chiller (refrigeration cycle device) 21, 71 Compressor 22 Condenser 23 Expansion valve 24 Evaporator 25 fans 26 Economizer heat exchanger 27 Economizer expansion valve 31 Compressor discharge pipe temperature sensor (data acquisition unit) 32 High-pressure side heat exchanger inlet gas pipe temperature sensor (data acquisition unit) 33 High-pressure side heat exchanger outlet liquid pipe temperature sensor (data acquisition unit) 34 Low-pressure side heat exchanger pipe temperature sensor (data acquisition section) 35 Water temperature sensor (data acquisition unit) 36 Return water temperature sensor (data acquisition part) 37 Compressor suction pipe temperature sensor (data acquisition section) 38 High-pressure side heat exchanger inlet pressure sensor (data acquisition unit) 39 Outside air temperature sensor (data acquisition section) 50, 51, 52 Refrigerant circuit 60 Control Unit 72 Four-way switching valve 73 Outdoor heat exchanger 74 Expansion valve 75a, 75b Indoor expansion valve 76a, 76b Indoor heat exchanger 77 Accumulator 80 Economizer circuit 81 Subcooling heat exchanger outlet gas pipe temperature sensor 82 Subcooling heat exchanger outlet liquid pipe temperature sensor 100 Detection device 101 Air conditioning equipment (refrigeration cycle equipment) 110 Input section (data acquisition section) 120 control section 130 Confirmation Department 140 Index holding part 150 Index switching section 160 Arithmetic section 161 Normal Prediction Model (Prediction Model) 170 Judgment section [Prior art documents] [Patent documents]

[0140] [Patent Document 1] Japanese Patent Application Publication No. 2019-2639

Claims

1. a refrigeration cycle device (10, 11, 101) having a refrigerant circuit (50, 51, 52) through which a refrigerant circulates; a data acquisition unit (110, 31 to 39) that acquires first operating data and second operating data from the refrigeration cycle device; a control unit (120) that performs a first refrigerant leakage determination using the first operating data or a second refrigerant leakage determination using the second operating data; Equipped with The control unit when the priority of the first refrigerant leakage determination is higher than the priority of the second refrigerant leakage determination, switching between the first refrigerant leakage determination and the second refrigerant leakage determination based on whether the first operating data is normal; Refrigerant leak detection system.

2. The control unit When the first operating data is normal, selecting the first refrigerant leakage determination using the first operating data; When the first operating data is abnormal, the second refrigerant leakage determination using the second operating data is selected. The refrigerant leak detection system of claim 1 .

3. The control unit uses a predicted value of a degree of subcooling, a predicted value of a degree of discharge superheat, or a predicted value of an expansion valve opening as the first operating data and the second operating data. The refrigerant leak detection system according to claim 1 or 2.

4. The data acquisition unit includes at least one of a condenser inlet temperature sensor (32), a condenser outlet temperature sensor (33), and a discharge temperature sensor (31). The refrigerant leak detection system according to claim 1 or 2.

5. a data acquisition step of acquiring first operating data and second operating data from a refrigeration cycle device (10, 11, 101) having a refrigerant circuit (50, 51, 52) through which a refrigerant circulates; a control step of performing a first refrigerant leakage determination using the first operating data or a second refrigerant leakage determination using the second operating data; Equipped with When the priority of the first refrigerant leakage determination is higher than the priority of the second refrigerant leakage determination, the control step switches between the first refrigerant leakage determination and the second refrigerant leakage determination based on whether the first operating data is normal. Refrigerant leak detection method.

6. A refrigeration cycle device having a refrigerant circuit (50, 51, 52) through which a refrigerant circulates, a data acquisition unit (31 to 39) that acquires first operating data and second operating data of the refrigeration cycle device; a control unit that performs a first refrigerant leakage determination using the first operating data or a second refrigerant leakage determination using the second operating data; Equipped with When the priority of the first refrigerant leakage determination is higher than the priority of the second refrigerant leakage determination, the control unit switches between the first refrigerant leakage determination and the second refrigerant leakage determination based on whether the first operating data is normal. Refrigeration cycle device (10, 11, 101).

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