Refrigeration cycle device

Abstract

To provide a refrigeration cycle device capable of improving accuracy of detecting a change point in an operating state.SOLUTION: A refrigeration cycle device comprises a refrigerant circuit, and a control device that performs a change point detection process to detect a change point in an operating state of the refrigerant circuit. In the change point detection process, the control device acquires time-series operating data of the refrigerant circuit in a set analysis interval, frequency-modulates the operating data using a periodic function of a fundamental frequency, and detects a change point in the frequency modulated operating data using a singular spectrum transformation method.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a refrigeration cycle device, and more particularly to analysis of an operating state of a refrigeration cycle device. [Background technology]

[0002] Conventionally, it is known to detect changes in the operating state of a refrigeration cycle device by using a method called "rule-based." In rule-based systems, normal and abnormal states are quantitatively defined in advance for each mechanism, thresholds are set for each, and changes in state are detected by comparing data representing the operating state with the thresholds. When using rule-based systems, it is necessary to define thresholds for each rule, and when there are many rules, it is not easy to evaluate and manage conflicts between rules. In addition, there are problems such as the inability to detect abnormal states that do not conform to the preset rules.

[0003] Conventionally, methods for estimating symptoms of abnormal conditions such as failures in refrigeration cycle devices are also known. For example, Patent Document 1 discloses a method for detecting abnormal symptoms of refrigerant leakage in a refrigeration system of a showcase using multivariate statistical process control. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-196144 Summary of the Invention [Problem to be solved by the invention]

[0005] Regardless of the above-mentioned method, if the noise superimposed on the signal is large compared to the change in the signal to be detected, the change point indicating the abnormal state may be erroneously detected. Alternatively, it is necessary to operate with a lowered sensitivity to avoid erroneous detection. Therefore, if the signal-to-noise ratio of the signal to be detected is low, the detection accuracy of the change point of the operating state decreases.

[0006] The present disclosure is devised to solve the above-mentioned problems, and has an object to provide a refrigeration cycle apparatus capable of improving the accuracy of detecting a change point in an operating state. [Means for solving the problem]

[0007] The refrigeration cycle apparatus according to the present disclosure includes a refrigerant circuit and a control device that performs a change-point detection process to detect change points in an operating state of the refrigerant circuit. In the change-point detection process, the control device acquires time-series operating data of the refrigerant circuit in a set analysis interval, frequency-modulates the operating data using a periodic function of a fundamental frequency, and detects change points in the frequency-modulated operating data using a singular spectrum transform method. Effect of the Invention

[0008] According to the refrigeration cycle device of the present disclosure, the operating data is frequency modulated and a change point is detected using a singular spectrum transform, thereby improving the accuracy of detecting the change point. [Brief description of the drawings]

[0009] [Figure 1] 1 is a refrigerant circuit diagram showing a configuration of a refrigeration cycle device according to a first embodiment. [Diagram 2] 1 is a control block diagram of a refrigeration cycle device according to a first embodiment. [Diagram 3] 4 is a flowchart showing the flow of operations of the control device according to the first embodiment. [Figure 4] 4 is a flowchart showing a flow of a change-point detection process in the first embodiment. [Diagram 5] FIG. 13 is a diagram showing an example of operational data of an analysis section. [Figure 6] FIG. 6 is a diagram showing an example of an abnormality level α of the operational data shown in FIG. 5. [Figure 7] FIG. 3 is a diagram showing an example of a display on a display unit in the first embodiment. [Figure 8] 10 is a flowchart showing the flow of operations of the control device according to the second embodiment. [Figure 9] FIG. 11 is a diagram for explaining rearrangement of operation data in the second embodiment. [Figure 10] 11 is a flowchart showing the flow of operations of the control device according to the third embodiment. [Figure 11] 13 is a diagram illustrating a method for setting a fundamental frequency fc in a modified example. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of a refrigeration cycle device according to the present disclosure will be described with reference to the drawings. In each drawing, components with the same reference numerals are the same or equivalent components, and this is common throughout the entire specification. Note that in each drawing, the relative dimensional relationship or shape of each component may differ from the actual one.

[0011] Embodiment 1 FIG. 1 is a refrigerant circuit diagram showing the configuration of a refrigeration cycle apparatus 100 according to a first embodiment. The refrigeration cycle apparatus 100 of this embodiment is an air-conditioning apparatus that heats and cools a room. As shown in FIG. 1, the refrigeration cycle apparatus 100 includes an outdoor unit 1 disposed outside a room, an indoor unit 2 disposed inside a room, and a control device 5 that controls the outdoor unit 1 and the indoor unit 2. The outdoor unit 1 and the indoor unit 2 are connected by piping and wiring such as a power line or a signal line. In addition, the control device 5 is connected to the outdoor unit 1 and the indoor unit 2 so as to be able to communicate with them by wire or wirelessly.

[0012] As shown in Fig. 1, the outdoor unit 1 includes a compressor 11, a flow path switching valve 12, an outdoor heat exchanger 13, an expansion valve 14, and an outdoor fan 15. The indoor unit 2 includes an indoor heat exchanger 21 and an indoor fan 22. The compressor 11, the flow path switching valve 12, the outdoor heat exchanger 13, the expansion valve 14, and the indoor heat exchanger 21 are connected by piping to form a refrigerant circuit. The refrigerant circulating in the refrigerant circuit of the refrigeration cycle device 100 is, for example, a natural refrigerant such as carbon dioxide, hydrocarbon, or helium, a chlorine-free refrigerant such as HFC410A or HFC407C, or a fluorocarbon refrigerant such as R22 or R134a.

[0013] The compressor 11 draws in and compresses a low-pressure gas refrigerant, and discharges it as a high-pressure gas refrigerant. As the compressor 11, for example, a reciprocating, rotary, scroll, or screw compressor is used. The operating frequency of the compressor 11 is controlled by the control device 5.

[0014] The flow path switching valve 12 switches between a cooling operation in which the outdoor heat exchanger 13 functions as a condenser and a heating operation in which the outdoor heat exchanger 13 functions as an evaporator. The flow path switching valve 12 is, for example, a four-way valve, and switching is controlled by the control device 5. During cooling operation, the flow path switching valve 12 is switched so that the refrigerant discharged from the compressor 11 flows into the outdoor heat exchanger 13, as shown by the solid line in Fig. 1. Also, during heating operation, the flow path switching valve 12 is switched so that the refrigerant discharged from the compressor 11 flows into the indoor heat exchanger 21, as shown by the dashed line in Fig. 1.

[0015] The outdoor heat exchanger 13 is, for example, a fin-tube type heat exchanger, and exchanges heat between the refrigerant flowing inside the circular or flat tubes and the air supplied by the outdoor fan 15. The outdoor heat exchanger 13 is disposed between the flow path switching valve 12 and the expansion valve 14. The outdoor heat exchanger 13 functions as an evaporator during heating operation, and functions as a condenser during cooling operation.

[0016] The expansion valve 14 is disposed between the outdoor heat exchanger 13 and the indoor heat exchanger 21, and reduces the pressure of the refrigerant to expand it. The expansion valve 14 is, for example, an electronic expansion valve whose opening degree is variable. The opening degree of the expansion valve 14 is controlled by the control device 5.

[0017] The outdoor fan 15 draws in outdoor air, passes it through the outdoor heat exchanger 13, and blows it out to the outside. The outdoor fan 15 is, for example, a propeller fan, a turbo fan, a sirocco fan, or a crossflow fan driven by a motor. The airflow rate of the outdoor fan 15 is controlled by the control device 5.

[0018] The indoor heat exchanger 21 is, for example, a fin-tube type heat exchanger, and exchanges heat between the refrigerant flowing inside the circular or flat tubes and the air blown by the indoor fan 22. The indoor heat exchanger 21 is disposed between the expansion valve 14 and the flow path switching valve 12. The indoor heat exchanger 21 functions as a condenser during heating operation, and functions as an evaporator during cooling operation.

[0019] The indoor fan 22 draws in indoor air, passes it through the indoor heat exchanger 21, and blows it out into the room. The indoor fan 22 is, for example, a propeller fan, a turbo fan, a sirocco fan, or a crossflow fan driven by a motor. The airflow rate of the indoor fan 22 is controlled by the control device 5.

[0020] The refrigeration cycle apparatus 100 also includes a plurality of sensors for measuring operation data. Specifically, the refrigeration cycle apparatus 100 includes a discharge temperature sensor 31 that measures the temperature of the refrigerant discharged from the compressor 11, and a suction temperature sensor 32 that measures the temperature of the refrigerant suctioned into the compressor 11. The discharge temperature sensor 31 is provided in a discharge pipe of the compressor 11, and the suction temperature sensor 32 is provided in a suction pipe of the compressor 11. In the following description, the temperature measured by the discharge temperature sensor 31 is referred to as the "discharge temperature," and the temperature measured by the suction temperature sensor 32 is referred to as the "suction temperature."

[0021] The refrigeration cycle apparatus 100 also includes a first refrigerant temperature sensor 33 and a second refrigerant temperature sensor 34 that measure the temperature of the refrigerant flowing into or out of the outdoor heat exchanger 13. The first refrigerant temperature sensor 33 measures the temperature of the refrigerant flowing into the outdoor heat exchanger 13 during cooling operation, and the second refrigerant temperature sensor 34 measures the temperature of the refrigerant flowing out of the outdoor heat exchanger 13 during cooling operation. The temperature measured by the first refrigerant temperature sensor 33 is referred to as the "first refrigerant temperature," and the temperature measured by the second refrigerant temperature sensor 34 is referred to as the "second refrigerant temperature."

[0022] The refrigeration cycle apparatus 100 also includes a third refrigerant temperature sensor 35 and a fourth refrigerant temperature sensor 36 that measure the temperature of the refrigerant flowing into or out of the indoor heat exchanger 21. The third refrigerant temperature sensor 35 measures the temperature of the refrigerant flowing into the indoor heat exchanger 21 during cooling operation, and the fourth refrigerant temperature sensor 36 measures the temperature of the refrigerant flowing out of the indoor heat exchanger 21 during cooling operation. The temperature measured by the third refrigerant temperature sensor 35 is referred to as the "third refrigerant temperature," and the temperature measured by the fourth refrigerant temperature sensor 36 is referred to as the "fourth refrigerant temperature."

[0023] Each of the above temperature sensors is constituted by a thermistor, for example. The refrigeration cycle apparatus 100 may include a temperature sensor or a pressure sensor other than the above temperature sensors. For example, the refrigeration cycle apparatus 100 may include an indoor temperature sensor provided in the indoor unit 2 to measure the temperature of the indoor air, or an outdoor air temperature sensor disposed outside the housing of the outdoor unit 1 to measure the temperature of the air outside the room where the outdoor unit 1 is installed. Furthermore, at least any of the discharge temperature sensor 31, the suction temperature sensor 32, and the first refrigerant temperature sensor 33 to the fourth refrigerant temperature sensor 36 may be a pressure sensor that measures the pressure of the refrigerant.

[0024] The control device 5 is a computer equipped with a processor such as a CPU, a memory, an I / O port, etc. The control device 5 controls the operation of the refrigeration cycle apparatus 100 based on instructions from a user input via a remote controller (not shown) of the refrigeration cycle apparatus 100 and measurement results of each temperature sensor. The control device 5 also detects and displays change points in the operating state of the refrigeration cycle apparatus 100 based on operation data measured by each temperature sensor of the refrigeration cycle apparatus 100.

[0025] (Cooling operation) The operation of the refrigeration cycle device 100 during cooling operation will be described. During cooling operation, first, the refrigerant compressed by the compressor 11 and turned into a high-temperature, high-pressure gas flows into the outdoor heat exchanger 13 functioning as a condenser. The refrigerant releases heat in the outdoor heat exchanger 13, changes phase from a high-temperature, high-pressure gas to a liquid, and heats the air passing through the outdoor heat exchanger 13. The refrigerant is then decompressed by the expansion valve 14, becomes a two-phase state in which low-temperature, low-pressure liquid and gas are mixed, and flows into the indoor heat exchanger 21 functioning as an evaporator. In the indoor heat exchanger 21, the refrigerant absorbs heat and changes phase from liquid to gas, cooling the air passing through the indoor heat exchanger 21. This cools the room. The refrigerant then flows into the compressor 11, and becomes a high-temperature, high-pressure gas again.

[0026] (Heating operation) The operation of the refrigeration cycle device 100 during heating operation will be described. During heating operation, the refrigerant compressed by the compressor 11 and turned into a high-temperature, high-pressure gas flows into the indoor heat exchanger 21 functioning as a condenser. The refrigerant releases heat in the indoor heat exchanger 21, changes phase from a high-temperature, high-pressure gas to a liquid, and heats the air passing through the indoor heat exchanger 21. This heats the room. The refrigerant is then decompressed by the expansion valve 14, becomes a two-phase state in which low-temperature, low-pressure liquid and gas are mixed, and flows into the outdoor heat exchanger 13 functioning as an evaporator. In the outdoor heat exchanger 13, the refrigerant absorbs heat and changes phase from liquid to gas, cooling the air passing through the outdoor heat exchanger 13. The refrigerant then flows into the compressor 11, and becomes a high-temperature, high-pressure gas again.

[0027] Fig. 2 is a control block diagram of the refrigeration cycle apparatus 100 according to the first embodiment. As shown in Fig. 2, the control device 5 of the refrigeration cycle apparatus 100 includes a control unit 51, a storage unit 52, and a display unit 53. The control unit 51 includes an operation control unit 511, a change point detection unit 512, and a display control unit 513. The operation control unit 511, the change point detection unit 512, and the display control unit 513 are functional units that are realized by a processor such as a CPU constituting the control unit 51 executing a program. Alternatively, at least one of the operation control unit 511, the change point detection unit 512, and the display control unit 513 may be realized by a processing circuit such as an ASIC or an FPGA.

[0028] The operation control unit 511 controls the outdoor unit 1 and the indoor unit 2 to perform cooling operation and heating operation. Specifically, the operation control unit 511 controls the operation frequency of the compressor 11, the switching of the flow path switching valve 12, the opening of the expansion valve 14, and the rotation speeds of the outdoor fan 15 and the indoor fan 22, based on the operation mode setting and set temperature input by the user and the measurement results of each temperature sensor. Note that a control unit (not shown) provided in the outdoor unit 1 or the indoor unit 2 may be configured to have the operation control unit 511, and the operation control unit 511 may be omitted from the control device 5.

[0029] The change point detection unit 512 analyzes the time-series operation data of the refrigeration cycle apparatus 100, and detects a change point in the operation state of the refrigeration cycle apparatus 100. The change point is a change point with respect to the operation state when the refrigeration cycle apparatus 100 is operating normally, and indicates a sign of an abnormal state such as a failure of any of the devices constituting the refrigeration cycle apparatus 100. The operation data indicates the operation state of the refrigeration cycle apparatus 100, and is time-series data of at least one of the discharge temperature measured by the discharge temperature sensor 31, the suction temperature measured by the suction temperature sensor 32, and the first refrigerant temperature to the fourth refrigerant temperature measured by the first refrigerant temperature sensor 33 to the fourth refrigerant temperature sensor 36.

[0030] For example, when a failure occurs in the refrigeration cycle apparatus 100, the change point detection unit 512 detects a change point in the operating state to clarify the cause of the failure. Alternatively, the change point detection unit 512 may detect a change point to find a sign of a failure when no failure occurs in the refrigeration cycle apparatus 100. In the former case, the change point detection unit 512 detects a change point by analyzing operation data acquired before the occurrence of a failure in the refrigeration cycle apparatus 100, and in the latter case, the change point is detected by periodically acquiring and analyzing operation data.

[0031] The display control unit 513 controls the display contents of the display unit 53. In the present embodiment, the display control unit 513 causes the display unit 53 to display the operation data of the refrigeration cycle apparatus 100 and the change points detected by the change point detection unit 512.

[0032] The storage unit 52 is, for example, a non-volatile semiconductor memory such as a ROM or a flash memory, a volatile semiconductor memory such as a RAM, an HDD, or an SSD. The storage unit 52 stores various data such as programs executed by the control unit 51 and thresholds used in executing the programs. The storage unit 52 also stores operation data acquired by each temperature sensor of the refrigeration cycle apparatus 100. At least a part of the information stored in the storage unit 52 may be stored in a storage device other than the control device 5, such as a cloud storage.

[0033] The display unit 53 is, for example, a liquid crystal display or an organic EL display, and displays the operation data of the refrigeration cycle apparatus 100 and the change points detected by the change point detection unit 512. The display unit 53 may be a display device separate from the control device 5, such as a user's smartphone or tablet.

[0034] 3 is a flowchart showing the flow of operation of the control device 5 according to the first embodiment. Here, the flow of detection and display of change points in the operating state of the refrigeration cycle apparatus 100, among the operations of the control device 5, will be described. First, the control device 5 acquires operating data from the discharge temperature sensor 31, the suction temperature sensor 32, and the first refrigerant temperature sensor 33 to the fourth refrigerant temperature sensor 36 (S1). The acquired operating data is stored in the memory unit 52. Here, for example, time-series data of at least one temperature for the most recent 10 minutes is acquired as operating data and stored in the memory unit 52.

[0035] Next, the change point detection unit 512 performs a change point detection process (S2). In this embodiment, the change point detection process is performed on at least one driving data. FIG. 4 is a flowchart showing the flow of the change point detection process in the first embodiment. As shown in FIG. 4, the change point detection unit 512 sets an analysis interval, and extracts driving data of the set analysis interval from the storage unit 52 (S21). The analysis interval includes the length and initial position of the driving data to be analyzed.

[0036] FIG. 5 is a diagram showing an example of the operation data of the analysis interval. As shown in FIG. 5, the change point detection unit 512 extracts the operation data of the analysis interval, for example, from 0 to 30 seconds of the operation data stored in the storage unit 52. The analysis interval may be set by the user or may be set according to an initial value stored in the storage unit 52. The operation data of the extracted analysis interval is expressed by the following formula (1). In formula (1), p indicates the number of operation data. For example, the operation data d1(t) of p=1 corresponds to the time series data of the discharge temperature of the discharge temperature sensor 31 in FIG. 2.

number

[0037] Returning to FIG. 4, the change point detection unit 512 performs a frequency modulation process on the extracted operating data by modulating it with a periodic function of a preset fundamental frequency fc (S22).

[0038] The operating data D after frequency modulation processing is expressed by the following formula (2): By performing frequency modulation processing on the operating data d, the signal-to-noise ratio of the operating data can be increased.

number

[0039] Next, the change point detection unit 512 analyzes the driving data D using the singular spectrum transform method. Specifically, the change point detection unit 512 acquires a multidimensional subspace of the reference section (S23) and a multidimensional subspace of the test space (S24). The history matrix X1, which is the multidimensional subspace of the reference section, and the test matrix X2, which is the multidimensional subspace of the test space, are each a part of time series data of the analysis section extracted from the driving data D of the analysis section, and are expressed by the following formula (3).

number

[0040] In formula (3), w is a window width indicating the length of data, k is a column size of the history matrix, and L is a lag indicating the number of overlapping data between the history matrix and the test matrix. The window width w, the column size k, and the lag L may be set by a user or may be stored in advance in the storage unit 52.

[0041] Then, the change point detection unit 512 acquires the left singular vectors of the history matrix X1 (S25) and the left singular vectors of the test matrix X2 (S26). First, a characteristic pattern v of each matrix is ​​obtained using the following equation (4).

number

[0042] Then, the change point detection unit 512 performs singular value decomposition on the history matrix X1 and the test matrix X2 to obtain the left singular vectors of the history matrix X1 and the left singular vectors of the test matrix X2.m (t) The left singular vector of the test matrix X2 is Q m (t) It is.

number

[0043] Then, the change-point detection unit 512 compares the left singular vectors of the reference section and the test section, and calculates the degree of anomaly α from the following equation (6) (S27). The degree of anomaly α is the distance between the time-series data of the reference section and the time-series data of the test section, and takes a value between 0 and 1.

number

[0044] Fig. 6 is a diagram showing an example of the degree of abnormality α of the operation data shown in Fig. 5. As shown in Fig. 6, the greater the change in the operation data, the greater the degree of abnormality α (closer to 1), and the smaller the change, the smaller the degree of abnormality α (closer to 0). In other words, the greater the value of the degree of abnormality α, the closer it is to an abnormal state, and the smaller the value, the closer it is to a normal state.

[0045] Returning to Fig. 4, the change-point detection unit 512 creates a data string β that is set to 1 when the degree of abnormality α is equal to or greater than the threshold th and is set to 0 when the degree of abnormality α is less than the threshold th (S28), as shown in equation (7). The threshold th is a preset value between 0 and 1. Fig. 6 shows a case of 0.5 as an example.

number

[0046] Then, the change-point detection unit 512 detects, as a change-point, a point in the data string β where the value changes from 0 to 1 or from 1 to 0 (S29). Here, as shown in Fig. 6, a point where the degree of abnormality α exceeds a threshold value th is detected as a change-point.

[0047] Returning to FIG. 3, the display control unit 513 superimposes the change points detected by the change point detection unit 512 on the driving data and displays them on the display unit 53 (S3). FIG. 7 is a diagram showing an example of a display on the display unit in the first embodiment. In FIG. 7, a dashed circle indicating a change point is displayed on the driving data. The method of displaying the change points is not limited to the example in FIG. 7, and various displays are possible. For example, the data string B may be displayed together with the driving data. Note that if no change point is detected by the change point detection unit 512, the display control unit 513 displays only the driving data on the display unit 53.

[0048] Then, the control device 5 judges whether or not to change the analysis interval (S4), and if the analysis interval is to be changed (S4: YES), the process returns to step S2, where a new analysis interval is set and change points are detected. For example, driving data from 31 to 60 seconds, which is the new analysis interval, is extracted and change points are detected. Whether or not to change the analysis interval may be judged based on a user's instruction, or the analysis interval may be automatically changed if no change points are detected in the current analysis interval.

[0049] On the other hand, if the analysis section is not to be changed (S4: NO), the control device 5 judges whether or not to acquire new driving data (S5). Then, if new driving data is to be acquired (S5: YES), the process returns to step S1 and new driving data is acquired. On the other hand, if new driving data is not to be acquired (S5: NO), the control device 5 ends the operation. Whether or not to acquire new driving data may be determined based on a user's instruction, or new driving data may be automatically acquired if no change point is detected in the driving data stored in the memory unit 52 even when the analysis section is changed.

[0050] As described above, in the refrigeration cycle apparatus 100 of the present embodiment, the operating data indicating the operating state can be analyzed to detect a change point indicating a symptom of an abnormal state. In addition, when detecting a change point, the operating data is not directly compared, but the singular values ​​are compared using the singular spectrum transform method, thereby reducing the influence of noise. Furthermore, when the operating data is discontinuous (when the operating data is not a periodic waveform), the calculation accuracy of the singular values ​​in the singular spectrum transform decreases. In contrast, in the refrigeration cycle apparatus 100 of the present embodiment, the frequency modulation process is performed on the operating data, thereby suppressing the decrease in the calculation accuracy of the singular values ​​in the singular spectrum transform. As a result, the detection accuracy of a change point in the operating state in the refrigeration cycle apparatus 100 can be improved.

[0051] Embodiment 2 A second embodiment will be described. The refrigeration cycle apparatus 100 of the second embodiment differs from the first embodiment in the method of displaying the operating data and the change points. The configuration of the refrigeration cycle apparatus 100 is the same as that of the first embodiment.

[0052] FIG. 8 is a flowchart showing the flow of the operation of the control device 5 according to the second embodiment. The processes of steps S101 and S102 in this embodiment are the same as the processes of steps S1 and S2 in the first embodiment. However, in this embodiment, it is assumed that change points of a plurality of driving data are detected. When a change point is detected by the change point detection unit 512, the display control unit 513 acquires time data of the change point in each driving data (S103). The time data is the time Tp of the first change point in each driving data.

[0053] Then, the display control unit 513 uses the time data of each operation data as an index to create abnormality order data Yp indicating the order when multiple operation data are arranged in ascending order (S104). For example, when the discharge temperature and the second refrigerant temperature are acquired as operation data and the time data of the discharge temperature is earlier than the time data of the second refrigerant temperature, the abnormality order data Yp indicates that the discharge temperature is first and the second refrigerant temperature is second. Then, the display control unit 513 rearranges the operation data in ascending or descending order based on the created abnormality order data Yp and displays them on the display unit 53 (S105).

[0054] FIG. 9 is a diagram for explaining rearrangement of driving data in the second embodiment. First, when data is acquired, as shown in FIG. 9(a), a plurality of driving data d1 to d3 are displayed regardless of the change points. Then, as shown in FIG. 9(b), the display control unit 513 creates abnormal order data Yp from the time data tp1 to tp3 of the change points of the plurality of driving data d1 to d3, and rearranges the driving data d1 to d3 based on the abnormal order data Yp. In the case of FIG. 9(b), the abnormal order data Yp is data indicating that the driving data d1 is first, the driving data d3 is second, and the driving data d2 is third, and the driving data d1 to d3 are rearranged and displayed in descending order. Then, as shown in FIG. 9(c), the display control unit 513 performs display so that the positions of the change points can be seen by displaying a frame or by using a different background color. The subsequent processes of steps S106 and S107 are the same as steps S4 and S5 of the first embodiment.

[0055] Even if a symptom of an abnormality can be detected by detecting a change point in the operating state in the refrigerant circuit of the refrigeration cycle device 100 as in the first embodiment, it is not easy to understand the path of the technical consideration that is the basis for the abnormality. In contrast, in the refrigeration cycle device 100 of the present embodiment, a plurality of pieces of operating data are displayed in ascending or descending order using the time data at which the change points occurred as an index, so that the order in which the change points occurred in the refrigerant circuit can be known. This allows the user to easily understand the path of the technical consideration that is the basis for the failure or abnormality. In particular, in the case of a closed circuit such as a refrigerant circuit, state changes are linked, so by clarifying the order in which the change points occurred, it becomes possible to easily identify the cause of the abnormal event.

[0056] Embodiment 3 A third embodiment will be described. The refrigeration cycle apparatus 100 of the third embodiment differs from the first embodiment in that an abnormal event is estimated and displayed based on a detected change point. The configuration of the refrigeration cycle apparatus 100 is the same as that of the first embodiment.

[0057] 10 is a flowchart showing the flow of the operation of the control device 5 according to embodiment 3. The processing of steps S111 to S114 in this embodiment is the same as the processing of steps S101 to S104 in embodiment 2. Then, the display control unit 513 in this embodiment calculates the distance S between the created abnormal order data Yp and the abnormal order template data Zp stored in the storage unit 52 (S115).

[0058] The abnormality order template data Zp is data indicating an occurrence order of change points of operation data when an abnormal event occurs in the refrigeration cycle apparatus 100. The abnormality order template data Zp is obtained by an experiment, past abnormality occurrence cases, simulation, or the like. The storage unit 52 pre-stores a plurality of abnormality order template data Zp corresponding to a plurality of abnormal events that may occur in the refrigeration cycle apparatus 100.

[0059] The distance S between the abnormal sequence data Yp and the abnormal sequence template data Zp is calculated by the Euclidean distance function shown in the following formula (8), for example. Note that, as the distance function for calculating the distance S, other than the Euclidean distance, the Manhattan distance or the non-metric multidimensional scaling method may be used.

number

[0060] The display control unit 513 calculates the distance S between each of the abnormal order data Yp and the plurality of abnormal order template data Zp, and identifies the abnormal event corresponding to the abnormal order template data Zp having the smallest distance S as the estimated abnormal event (S116). Then, the display control unit 513 displays the identified estimated abnormal event on the display unit 53 (S117). The subsequent processes of steps S118 and S119 are the same as steps S4 and S5 in the first embodiment.

[0061] As described above, in the refrigeration cycle apparatus 100 of the present embodiment, a predicted abnormal event can be identified by comparing the distance between the abnormality sequence data Yp and the abnormality sequence template data Zp. This allows a rapid response to the abnormal event.

[0062] The above is an explanation of the embodiment, but the present disclosure is not limited to the above embodiment and can be modified in various ways without departing from the spirit of the present disclosure. In addition, the present disclosure includes all combinations of the configurations shown in the above embodiment that can be combined. For example, in the above embodiment, the refrigeration cycle device 100 is an air conditioner, but the refrigeration cycle device 100 may be a heat pump chiller, a cooling-only device without a device that can switch between heating and cooling, a refrigerator for cooling a refrigerated warehouse, or a water heater.

[0063] Furthermore, the display unit 53 of the control device 5 may perform both the display of the second embodiment and the display of the third embodiment. Furthermore, in the second and third embodiments, the change point may be detected by a method different from that of the first embodiment. For example, the frequency modulation and the singular spectrum conversion may not be performed on the driving data, and the change point may be detected by comparing the reference driving data with the measured driving data.

[0064] In the above embodiment, the operation data is time series data of the temperature or pressure of the refrigerant at each point of the refrigerant circuit, but the operation data is not limited to this. For example, the operation data may be time series data of a control signal such as the rotation speed of the compressor 11 or the opening degree of the expansion valve 14 of the refrigeration cycle device 100, and a change point may be detected.

[0065] Furthermore, when the physical relationships between the control signals of the temperature sensors or pressure sensors installed at various locations in the refrigerant circuit of the refrigeration cycle apparatus 100 and the components such as the compressor 11 that configure the refrigerant circuit are clear in advance and two or more pieces of operating data that are closely related to each other are known, in the second and third embodiments, when rearranging the operating data in ascending and descending order, the two or more pieces of operating data that are closely related to each other may be corrected to become the same abnormal order data Yp. In other words, two or more pieces of operating data that are closely related to each other may be displayed as a single change.

[0066] Also, in the change point detection process of Embodiment 1, even if the change amount ΔVe of the operation data is large, when the duration ΔTe of the abnormal state is short and shorter than half of the period Tc of the fundamental frequency fc (ΔTe < Tc / 2), the calculated abnormality degree α becomes small and the detection sensitivity relatively decreases. On the other hand, even if the change amount ΔVe of the operation data is small, when the duration ΔTe of the abnormal state is long and longer than half of the period of the fundamental frequency (ΔTe > Tc / 2), the abnormality degree α does not become small and the detection sensitivity does not relatively decrease. As an example, in the data of FIG. 5, the value of the operation data transitions from a low state to a high state, and the time during which it takes a high value continues for at least 20 seconds. In order to find this change point, the fundamental frequency fc needs to be 0.1 Hz or more.

[0067] Therefore, when performing the frequency modulation process, the change point detection unit 512 may perform the frequency modulation process using periodic functions of a plurality of different frequencies, perform a series of analyses, and set the fundamental frequency fc. FIG. 11 is a diagram for explaining a method of setting the fundamental frequency fc in a modified example. In FIG. 11, it is a graph showing the results of investigating the number of change points detected by sweeping the fundamental frequency fc in the case where the duration ΔTe of the abnormal state is long and the case where it is short. The circles in FIG. 11 indicate the operation data when the duration ΔTe of the abnormal state is long, and the triangles indicate the operation data when the duration ΔTe of the abnormal state is short.

[0068] As shown in FIG. 11, the number Q of detected change points increases as the fundamental frequency fc used for frequency conversion increases. This is because as the fundamental frequency fc increases, the detection sensitivity relatively decreases (the SN ratio for detecting change points decreases), and the possibility of misdetecting measurement noise as a change point increases. On the other hand, when the fundamental frequency fc is low, the possibility of accurately detecting a change point is high, and the number Q of detected change points decreases. Therefore, it is necessary to set the fundamental frequency fc with high sensitivity for detecting change points. As a premise, the noise superimposed on the operation data is assumed to be white noise. Also, the intervals between the plurality of frequencies used as the fundamental frequency fc are assumed to be equal.

[0069] In order to determine a fundamental frequency fc having a high sensitivity for detecting a change point, the change point detection unit 512 checks the number Q of change points detected when a series of analyses are performed by gradually lowering the frequency from a high frequency. Then, the change point detection unit 512 sets the fundamental frequency fc to a frequency where the difference between the number Q of change points at two consecutive points (two consecutive frequencies) is small or a frequency close to the frequency. In the example of FIG. 11, a frequency within the range Rf is set to the fundamental frequency fc. This improves the detection accuracy of the change point, and it is possible to obtain the abnormality degree α reflecting the amount of change ΔVe in the operation data and the abnormality degree α reflecting the duration ΔTe of the abnormal state. In this case, the display control unit 531 may display the abnormality degree α based on the change point obtained for each frequency on the display unit 53. Alternatively, the change point detection unit 512 may set a different fundamental frequency fc for each operation data.

[0070] Various aspects of the present disclosure are summarized below as appendices.

[0071] (Appendix 1) A refrigerant circuit; A control device that performs a change point detection process to detect a change point of an operating state in the refrigerant circuit, The control device, in the change point detection process, Acquire time-series operation data of the refrigerant circuit in a set analysis section; The operation data is frequency modulated using a periodic function of a fundamental frequency; A refrigeration cycle apparatus that detects the change point of the operating data that has been frequency modulated using a singular spectrum transformation method. (Appendix 2) The control device, in the change point detection process, Calculating an abnormality degree of the operation data subjected to the frequency modulation process using the singular spectrum transformation method; A data string is generated in which the degree of abnormality is set to 1 when the degree of abnormality is equal to or greater than a threshold value and set to 0 when the degree of abnormality is less than the threshold value; The refrigeration cycle apparatus according to claim 1, wherein the change point is a point where the value of the data string changes from 0 to 1, or from 1 to 0. (Appendix 3) 3. The refrigeration cycle apparatus according to claim 1, further comprising a display unit that displays the operating data and the change points. (Appendix 4) The control device includes: Detecting the change points of the plurality of pieces of driving data; creating abnormality sequence data of the plurality of operation data based on a time of the first change point in the plurality of operation data; The refrigeration cycle apparatus according to claim 3, wherein the display unit rearranges and displays the plurality of pieces of operation data based on the abnormality order data. (Appendix 5) The control device includes: Detecting the change points of the plurality of pieces of driving data; creating abnormality sequence data of the plurality of operation data based on a time of the first change point in the plurality of operation data; The refrigeration cycle apparatus according to claim 3, wherein the abnormality sequence data is compared with a plurality of abnormality sequence template data corresponding to a plurality of abnormal events to identify an estimated abnormal event. (Appendix 6) The refrigeration cycle apparatus according to claim 5, wherein the display unit displays the estimated abnormal event. (Appendix 7) The refrigeration cycle apparatus according to any one of claims 1 to 6, wherein the control device performs the frequency modulation process using the periodic function of a plurality of different frequencies to detect the change points, and sets the fundamental frequency based on the number of the detected change points. [Explanation of symbols]

[0072] 1 outdoor unit, 2 indoor unit, 5 control device, 11 compressor, 12 flow path switching valve, 13 outdoor heat exchanger, 14 expansion valve, 15 outdoor fan, 21 indoor heat exchanger, 22 indoor fan, 31 discharge temperature sensor, 32 suction temperature sensor, 33 first refrigerant temperature sensor, 34 second refrigerant temperature sensor, 35 third refrigerant temperature sensor, 36 fourth refrigerant temperature sensor, 51 control unit, 52 memory unit, 53 display unit, 100 refrigeration cycle device, 511 operation control unit, 512 change point detection unit, 513 display control unit.

Claims

1. A refrigerant circuit; A control device that performs a change point detection process to detect a change point of an operating state in the refrigerant circuit, The control device, in the change point detection process, Acquire time-series operation data of the refrigerant circuit in a set analysis section; The operation data is frequency modulated using a periodic function of a fundamental frequency; A refrigeration cycle apparatus that detects the change point of the operating data that has been frequency modulated using a singular spectrum transformation method.

2. The control device, in the change point detection process, Calculating an abnormality degree of the operation data subjected to the frequency modulation process using the singular spectrum transformation method; A data string is generated in which the degree of abnormality is set to 1 when the degree of abnormality is equal to or greater than a threshold value and set to 0 when the degree of abnormality is less than the threshold value; 2. The refrigeration cycle apparatus according to claim 1, wherein the change point is a point at which the value of the data string changes from 0 to 1 or from 1 to 0.

3. The refrigeration cycle apparatus according to claim 1 or 2, further comprising a display unit that displays the operating data and the change points.

4. The control device includes: Detecting the change points of the plurality of pieces of driving data; creating abnormality sequence data of the plurality of operation data based on a time of the first change point in the plurality of operation data; The refrigeration cycle apparatus according to claim 3 , wherein the display unit rearranges and displays the plurality of pieces of operation data based on the abnormality order data.

5. The control device includes: Detecting the change points of the plurality of pieces of driving data; creating abnormality sequence data of the plurality of operation data based on a time of the first change point in the plurality of operation data; 4. The refrigeration cycle apparatus according to claim 3, wherein an estimated abnormal event is identified by comparing the abnormal sequence data with a plurality of abnormal sequence template data corresponding to a plurality of abnormal events.

6. The refrigeration cycle apparatus according to claim 5 , wherein the display unit displays the estimated abnormal event.

7. 3. The refrigeration cycle apparatus according to claim 1, wherein the control device performs the frequency modulation process using the periodic function of a plurality of different frequencies to detect the change points, and sets the fundamental frequency based on the number of the detected change points.

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