Fault diagnosis system, refrigeration cycle system, fault diagnosis method, fault diagnosis program, and air conditioner

Abstract

To improve determination accuracy when determining presence / absence of leakage of a refrigerant from an index value based on operation data in a refrigeration cycle system.SOLUTION: In a fault diagnosis program (120) having a control section (121), the control section (121) acquires operation data, and determines presence / absence of leakage of a refrigerant with the usage of a value related to an expansion valve (400) included in the acquired operation data and a value measured by a temperature sensor installed in any of a plurality of paths (331-336) before merging in an outlet of a heat exchanger (300). Any of the plurality of paths (331-336) before merging in the outlet of the heat exchanger (300) includes paths (334-336) positioned at a height lower than an average value of heights of the plurality of paths.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a fault diagnosis system, a refrigeration cycle system, a fault diagnosis method, a fault diagnosis program, and an air conditioner. [Background technology]

[0002] BACKGROUND ART In a refrigeration cycle system, a technique is known for determining the presence or absence of a refrigerant leak from an index value based on operation data. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-25509 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when values ​​related to the expansion valve (such as the opening degree of the expansion valve) and values ​​related to sensors around the high pressure (such as the temperature of the liquid pipe at the outlet of the condenser) are used as the operating data, the accuracy of the determination during low load operation decreases.

[0005] The present disclosure aims to improve the accuracy of determining whether or not a refrigerant leaks from an index value based on operating data in a refrigeration cycle system. [Means for solving the problem]

[0006] A first aspect of the present disclosure is A fault diagnosis system (120) having a control unit (121), The control unit (121) Acquire driving data, determining whether or not there is a refrigerant leak using a value related to the expansion valve (400) included in the acquired operation data and a value measured by a temperature sensor installed in one of the paths (331 to 336) before joining at the outlet of the heat exchanger (300); Among the plurality of paths (331-336) before joining at the outlet of the heat exchanger (300), there is included a path (334-336) located at a height lower than the average height of the plurality of paths.

[0007] According to the first aspect of the present disclosure, in a refrigeration cycle system including the fault diagnosis system (120), it is possible to improve the accuracy of determining whether or not a refrigerant leaks from an index value based on operating data.

[0008] A second aspect of the present disclosure is a fault diagnosis system (120) according to the first aspect, The temperature sensor installed in one of the paths (331-336) before joining at the outlet of the heat exchanger (300) is a defrost sensor for detecting frost formation.

[0009] A third aspect of the present disclosure is a fault diagnosis system (120) according to the first or second aspect, Among the plurality of paths (331-336) before joining at the outlet of the heat exchanger (300), one path includes the path (336) located at the bottom of the plurality of paths arranged in the vertical direction.

[0010] A fourth aspect of the present disclosure is a fault diagnosis system (120) according to the first or second aspect, Among the plurality of paths (331-336) before the merging at the outlet of the heat exchanger (300), there is included a path before the merging that has a lower temperature than the temperature of the path after the merging at the outlet of the heat exchanger (300).

[0011] A fifth aspect of the present disclosure is a fault diagnosis system (120) according to any one of the first to fourth aspects, The value related to the expansion valve (400) includes any one of the opening degree of the expansion valve, the refrigerant flow rate ratio, the CV value of the expansion valve, and the cooling capacity calculated based on the opening degree of the expansion valve.

[0012] A sixth aspect of the present disclosure is a fault diagnosis system (120) according to any one of the first to fifth aspects, The expansion valve (400) includes any one of a condenser outlet expansion valve, a subcooling heat exchange expansion valve, an economizer heat exchange expansion valve, and an evaporator inlet expansion valve.

[0013] A seventh aspect of the present disclosure is a fault diagnosis system (120) according to any one of the first to fifth aspects, The expansion valve (400) is disposed in the refrigerant circuit (110) between the outlet of the condenser and the inlet of the evaporator.

[0014] An eighth aspect of the present disclosure is a refrigeration cycle system (100), The fault diagnosis system (120) according to any one of the first to seventh aspects is provided.

[0015] According to the eighth aspect of the present disclosure, in a refrigeration cycle system, it is possible to improve the accuracy of determination when determining the presence or absence of refrigerant leakage from an index value based on operation data.

[0016] A ninth aspect of the present disclosure is a fault diagnosis method for a refrigeration cycle system (100), comprising: acquiring operational data; determining whether or not there is a leakage of refrigerant by using a value related to the expansion valve (400) included in the acquired operation data and a value measured by a temperature sensor installed in one of the paths (331 to 336) before joining at an outlet of the heat exchanger (300); Among the plurality of paths (331-336) before joining at the outlet of the heat exchanger (300), there is included a path (334-336) located at a height lower than the average height of the plurality of paths.

[0017] According to the ninth aspect of the present disclosure, in a refrigeration cycle system, it is possible to improve the accuracy of determination when determining the presence or absence of refrigerant leakage from an index value based on operation data.

[0018] A tenth aspect of the present disclosure is a fault diagnosis program, A control unit (121) of the fault diagnosis system acquiring operational data; determining whether or not there is a refrigerant leak by using a value related to the expansion valve (400) included in the acquired operation data and a value measured by a temperature sensor installed in one of the paths (331 to 336) before joining at the outlet of the heat exchanger (300); Among the plurality of paths (331-336) before joining at the outlet of the heat exchanger (300), there is included a path (334-336) located at a height lower than the average height of the plurality of paths.

[0019] According to the tenth aspect of the present disclosure, in a refrigeration cycle system equipped with a fault diagnosis system in which the above-mentioned fault diagnosis program is executed, the accuracy of determining whether or not a refrigerant leaks from an index value based on operating data can be improved.

[0020] An eleventh aspect of the present disclosure is an air conditioner (10), The present invention includes a refrigeration cycle system (100) according to the eighth aspect.

[0021] According to the eleventh aspect of the present disclosure, it is possible to improve the accuracy of determination when determining the presence or absence of refrigerant leakage from an index value based on operating data in an air conditioner. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a diagram illustrating an example of a system configuration of a refrigeration cycle system provided in an air conditioner. [Figure 2]FIG. 10 is a diagram showing the difference in index value depending on whether or not there is a refrigerant leak when a conventional index value is used. [Figure 3] FIG. 10 is a diagram showing an example of operational data in which a difference value between the presence and absence of refrigerant leakage is large in a refrigeration cycle during low load operation, and an example of measurement positions of the operational data. [Figure 4] FIG. 3 is a diagram showing an example of an index value used in the refrigeration cycle system according to the first embodiment. [Figure 5] FIG. 4 is a diagram showing the effect of an index value used in the refrigeration cycle system according to the first embodiment. [Figure 6] FIG. 2 illustrates an example of a hardware configuration of a control unit. [Figure 7] FIG. 10 is a diagram illustrating an example of a functional configuration (learning phase) of a control unit. [Figure 8] 10 is an example of a flowchart illustrating a flow of a learning process performed by a control unit. [Figure 9] FIG. 10 is a diagram illustrating an example of a functional configuration (inference phase) of a control unit. [Figure 10] 10 is an example of a flowchart showing the flow of a refrigerant leakage determination process performed by a control unit. [Figure 11] FIG. 3 is a diagram showing a specific example of an index value used in a refrigeration cycle system having a first refrigerant circuit. [Figure 12] FIG. 4 is a diagram showing a specific example of an index value used in a refrigeration cycle system having a second refrigerant circuit. [Figure 13] FIG. 10 is a diagram showing a specific example of an index value used in a refrigeration cycle system having a third refrigerant circuit. [Figure 14] 10A and 10B are diagrams illustrating a specific example of a refrigerant leakage determination process performed by a control unit. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, each embodiment will be described with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configuration are designated by the same reference numerals, and redundant description will be omitted.

[0024] [First embodiment] <System configuration of refrigeration cycle system> First, a description will be given of the system configuration of a refrigeration cycle system provided in an air conditioner according to Embodiment 1. Fig. 1 is a diagram showing an example of the system configuration of a refrigeration cycle system provided in an air conditioner.

[0025] 1, a refrigeration cycle system 100 included in an air conditioner 10 according to the first embodiment has a refrigerant circuit 110. In the refrigerant circuit 110, a refrigeration cycle is performed in which a filled refrigerant is compressed, condensed or releases heat, decompressed, evaporated, and then compressed again.

[0026] The refrigeration cycle system 100 also has a control system (not shown) for controlling the refrigeration cycle, which is connected to each device in the refrigerant circuit 110, as well as a fault diagnosis system 120 for determining whether or not there is a leak of the refrigerant filled in the refrigerant circuit 110. The fault diagnosis system 120 acquires operating data from the control system, and a control unit 121 calculates a predetermined index value based on the acquired operating data to determine whether or not there is a leak of the refrigerant.

[0027] 1, the fault diagnosis system 120 has a control unit 121 and is configured separately from the control system. However, the fault diagnosis system 120 may be configured as an integral part of the control system, and the process of determining whether or not there is a refrigerant leak may be executed by a control unit (not shown) included in the control system.

[0028] <Index value used to determine whether or not there is a refrigerant leak> Next, an index value used by the control unit 121 when determining whether or not there is a refrigerant leak will be described.

[0029] (1) Problems with conventional index values First, the problems with the conventional index values ​​used to determine whether or not there is a refrigerant leak will be described. Conventionally, the index values ​​used to determine whether or not there is a refrigerant leak have been, for example, Expansion valve related values ​​(e.g., expansion valve opening), Temperature data measured by a temperature sensor installed at the outlet of the heat exchanger functioning as a condenser; etc. were used.

[0030] On the other hand, when the conventional index value is used, there is a problem that the accuracy of determining whether or not there is a refrigerant leak is reduced in the refrigeration cycle during low load operation. Figure 2 is a diagram showing the difference in index value depending on whether or not there is a refrigerant leak when the conventional index value is used.

[0031] In Fig. 2, the horizontal axis represents the load factor in the refrigeration cycle. Also, in Fig. 2, the vertical axis represents the percentage of the index value that is the difference between the index value calculated in the refrigeration cycle when the refrigerant filled in the refrigerant circuit is not leaking and the index value calculated in the refrigeration cycle when the refrigerant filled in the refrigerant circuit is leaking. Also, different symbols (circle, triangle, square, diamond, cross) plotted in the graph in Fig. 2 indicate different outdoor air temperatures.

[0032] As shown in Figure 2, in the case of high load (load factor = 75%) operation and medium load (load factor = 50%) operation, the proportion of the difference value in the index value is relatively large. Therefore, in the refrigeration cycle during high load operation or medium load operation, it is possible to determine whether or not there is a refrigerant leak even using conventional index values. For example, if the monitored index value fluctuates by 0.2% or more from the index value calculated in advance in a refrigeration cycle when there is no refrigerant leak, it can be determined that there is a refrigerant leak.

[0033] On the other hand, as shown in Figure 2, when the refrigeration cycle is operating at a low load (load factor = 25%), the proportion of the difference value in the index value is extremely small. Therefore, when using the conventional index value, it is difficult to determine whether or not there is a refrigerant leak in the refrigeration cycle during low load operation.

[0034] For this reason, in addition to conventional index values, it is desirable to use index values ​​that have a large difference between the presence and absence of refrigerant leakage in refrigeration cycles operating at low loads when determining whether or not there is a refrigerant leak.

[0035] (2) Operating data showing large differences in values ​​due to the presence or absence of refrigerant during low-load operation In order to calculate an index value with a large difference depending on whether or not there is refrigerant leakage in the refrigeration cycle during low load operation, the applicant focused on the temperature data of the path before the merging at the outlet of the heat exchanger that functions as a condenser as operating data.

[0036] 3 is a diagram showing an example of operational data in which the difference value between the presence and absence of refrigerant leakage is large in a refrigeration cycle during low load operation, and the measurement positions of the operational data. As shown in Fig. 3, heat exchanger 300 functioning as a condenser has path branching section 320, and multiple paths (paths 331 to 336) through which the respective refrigerants branched by path branching section 320 are transported are installed inside the heat exchanger body.

[0037] As shown in FIG. 3, the heat exchanger 300 has a path junction 310 where the divided refrigerants join together, and a plurality of paths (paths 331 to 336) are connected at the path junction 310.

[0038] 3, a temperature sensor 350 for measuring the temperature of the refrigerant after the paths convergence section 310 is installed near the path convergence section 310. Note that the "temperature data measured by a temperature sensor installed at the outlet of the heat exchanger functioning as a condenser," which is the operating data used to calculate the conventional index value described above, is, for example, the temperature data measured by the temperature sensor 350.

[0039] Here, the applicant experimentally installed temperature sensors 341 to 346 on paths 331 to 336 to measure temperature data of the paths before merging at the heat exchanger outlet. The applicant also measured the temperature data of each of the temperature sensors 341 to 346 in a state where there was no refrigerant leakage and in a state where there was refrigerant leakage in a refrigeration cycle during low load operation.

[0040] 3, reference numeral 370 denotes temperature data (experimental results) measured by temperature sensors 341 to 346 in a state where there is no refrigerant leakage. The figures shown at the bottom left of each rectangular area indicated by reference numeral 370 schematically represent the amount of refrigerant flowing through the corresponding path.

[0041] Furthermore, reference numeral 380 indicates temperature data (experimental results) measured by temperature sensors 341 to 346 in a state where refrigerant is leaking. The figures shown at the bottom left of each rectangular area indicated by reference numeral 380 schematically indicate the amount of refrigerant flowing through the corresponding path.

[0042] When paths 331-336 are arranged vertically as in heat exchanger 300 in Fig. 3, the amounts of refrigerant diverted from each path are not equal. Specifically, as indicated by reference numerals 370 and 380, the amount of refrigerant diverted from each path is greater as the path is arranged downward, and is smaller as the path is arranged upward. According to the above experiment, as indicated by reference numerals 370 and 380, the difference between the temperature data measured when there is no refrigerant leakage and the temperature data measured when there is a refrigerant leakage is greater as the amount of diverted refrigerant from a path is greater.

[0043] From the above, the following can be said about the temperature data used when calculating the index value. It is desirable to use temperature data measured by at least one or more of the temperature sensors 342 to 346, excluding the temperature sensor 341 installed on the path 331 located at the highest height, among the temperature sensors installed on each path. It is more desirable to use the temperature data measured by one or more of the temperature sensors 344 to 346 installed on paths 334 to 336, which are located at a height lower than the average height of the multiple paths (symbol 360), among the temperature sensors installed on each path. Of the temperature sensors installed on each path, it is most desirable to use the temperature data measured by the temperature sensor installed on the path 336, which is located at the bottom. Of the temperature sensors installed in each path, it is desirable to use the temperature data measured by the temperature sensor installed in the path before the junction, which has a lower temperature than the temperature of the path after the junction at the outlet of the heat exchanger (300).

[0044] (3) Example of index value Next, a description will be given of index values ​​used in the refrigeration cycle system 100 according to the first embodiment. Fig. 4 is a diagram showing an example of index values ​​used in the refrigeration cycle system according to the first embodiment.

[0045] Based on the above experimental results, as shown in FIG. 4, in the refrigeration cycle system 100 according to the first embodiment, the following index values ​​are used: Value D for expansion valve 400 EV (e.g., the opening degree of the expansion valve 400), Temperature data D measured by temperature sensors 344 to 346 installed in paths before the junction at the outlet of the heat exchanger 300 functioning as a condenser (here, paths 334 to 336 located at a height lower than the average height of the plurality of paths (reference numeral 360)). T , is used.

[0046] The above operating data (value D related to the expansion valve 400) EV , temperature data D T ) may be used to calculate the index value. For example, the value D EV and temperature data D T In addition, when the weighted sum is used as the index value, the value D EVand temperature data D T The index value may be a value obtained by further weighting and adding the other operational data.

[0047] (4) Comparison of index values Next, a comparison result between a case where the presence or absence of refrigerant leakage is determined using a conventional index value and a case where the presence or absence of refrigerant leakage is determined using an index value of the refrigeration cycle system 100 according to the first embodiment will be described. FIG. 5 is a diagram showing the effect of the index value used in the refrigeration cycle system according to the first embodiment. In FIG. 5, a graph 501 represents an evaluation value when a conventional index value is used. As shown in FIG. 5, the evaluation value of the graph 501 is μ (index value 100%): the average value of the conventional index value calculated in the refrigeration cycle during low load operation without refrigerant leakage, μ (index value_90%): the average value of the conventional index value calculated in the refrigeration cycle during low load operation with 10% refrigerant leakage, ·σ (index value_100%): The variance of the conventional index value calculated in the refrigeration cycle during low load operation without refrigerant leakage, ·σ(index value_90%): Variance of the conventional index value calculated in the refrigeration cycle during low load operation with 10% refrigerant leakage, It is calculated using

[0048] 5, a graph 502 represents an evaluation value when the index value of the refrigeration cycle system 100 according to the first embodiment is used. As shown in FIG. 5, the evaluation value of the graph 502 is μ (index value_100%): the average value of the index value of the refrigeration cycle system 100 according to the first embodiment calculated in the refrigeration cycle during low load operation in a state where there is no refrigerant leakage, μ (index value_90%): the average value of the index value of the refrigeration cycle system 100 according to the first embodiment calculated in the refrigeration cycle during low load operation in a state where 10% of the refrigerant is leaking, σ (index value_100%): variance of the index value of the refrigeration cycle system 100 according to the first embodiment calculated in the refrigeration cycle during low load operation in a state where there is no refrigerant leakage, σ (index value_90%): variance of the index value of the refrigeration cycle system 100 according to the first embodiment calculated in the refrigeration cycle during low load operation in a state where 10% of the refrigerant is leaking, It is calculated using

[0049] As is clear from FIG. 5, the index value of the refrigeration cycle system 100 according to the first embodiment has a higher evaluation value in the refrigeration cycle during low load operation compared to the conventional index value, making it easier to determine whether or not there is a refrigerant leak.

[0050] <Hardware configuration of the control unit> Next, the hardware configuration of the control unit 121 will be described. Fig. 6 is a diagram showing an example of the hardware configuration of the control unit. As shown in Fig. 6, the control unit 121 has a processor 601, a memory 602, an auxiliary storage device 603, an I / F (Interface) device 604, and a communication device 605. The hardware components of the control unit 121 are connected to each other via a bus 606.

[0051] The processor 601 has various arithmetic devices such as a CPU (Central Processing Unit), etc. The processor 601 reads various programs (for example, a fault diagnosis program, etc.) into the memory 602 and executes them.

[0052] The memory 602 includes a main storage device such as a ROM (Read Only Memory) and a RAM (Random Access Memory).

[0053] The auxiliary storage device 603 stores various programs and various information used when the processor 601 executes the various programs.

[0054] The I / F device 604 is a connection device for connecting each device in the refrigeration cycle system 100 with the control unit 121. The communication device 605 is a communication device for connecting to a network (not shown).

[0055] <Functional configuration of the control unit and flow of processing executed by the control unit> Next, the functional configuration of the control unit 121 and the flow of processing executed by the control unit 121 will be described. By executing the fault diagnosis program, the control unit 121 functions as a learning unit and executes learning processing in the learning phase. Also, by executing the fault diagnosis program, the control unit 121 functions as an inference unit and executes refrigerant leakage determination processing in the inference phase. Therefore, the functional configuration and processing in the learning phase and the functional configuration and processing in the inference phase will be described separately below.

[0056] (1) Learning Phase (1-1) Functional configuration First, the functional configuration of the control unit 121 in the learning phase will be described. Fig. 7 is a diagram showing an example of the functional configuration of the control unit (learning phase).

[0057] As described above, the fault diagnosis program is executed in the learning phase, causing the control unit 121 to function as a learning unit 700. As shown in Fig. 7 , the learning unit 700 includes an expansion valve feature amount acquisition unit 701, a temperature feature amount acquisition unit 702, an index value calculation unit 703, an input data acquisition unit 704, a learning model 705, and a comparison / change unit 706.

[0058] The expansion valve characteristic quantity acquisition unit 701 acquires a value D relating to the expansion valve as operation data in a refrigeration cycle in a state where there is no refrigerant leakage. EV As described above, the value D relating to the expansion valve is acquired at predetermined intervals. EV For example, the expansion valve characteristic amount acquisition unit 701 acquires a value D EV are notified to the index value calculation unit 703 in sequence.

[0059] The temperature feature quantity acquisition unit 702 acquires temperature data D as measurement data in a refrigeration cycle in a state where there is no refrigerant leakage. T As described above, the temperature data D T is temperature data measured by a temperature sensor installed in a path located at a height lower than the average height of the plurality of paths before joining at the outlet of the heat exchanger 300 that functions as a condenser. The temperature sensor installed in a path located at a height lower than the average height of the plurality of paths is, for example, the temperature sensors 344 to 346. The temperature feature amount acquisition unit 702 uses the temperature data D acquired at predetermined intervals T are notified to the index value calculation unit 703 in sequence.

[0060] The index value calculation unit 703 calculates the expansion valve characteristic value D EV The temperature data D is sequentially notified by the temperature feature amount acquisition unit 702. T The index value is calculated using the following equation: In the learning phase, the index value calculated by the index value calculation unit 703 is the index value in a state where there is no refrigerant leakage.

[0061] Furthermore, the index value calculation unit 703 stores the calculated index value in the learning data storage unit 710 as correct data of the learning data 711 .

[0062] The input data acquisition unit 704 acquires the value D related to the expansion valve in the refrigeration cycle when there is no refrigerant leakage. EV and temperature data D T The input data acquisition unit 704 acquires the acquired operating data at predetermined intervals, such as the condensation temperature, evaporation temperature, compressor rotation speed, outside air temperature, and degree of superheat. The input data acquisition unit 704 stores the acquired operating data in the learning data storage unit 710 as input data for learning data 711.

[0063] The learning model 705 uses input data included in the learning data 711 (values ​​D related to the expansion valve) EV and temperature data D TBy inputting operational data other than the above, such as condensation temperature, evaporation temperature, compressor rotation speed, outside air temperature, degree of superheat, etc., output data is output.

[0064] The comparison and modification unit 706 reads out correct data (index value) included in the learning data 711, and calculates the error between the correct data and the output data output from the learning model 705. The comparison and modification unit 706 also performs a learning process on the learning model 705 by updating the model parameters of the learning model 705 based on the calculated error. As a result, the learning unit 700 performs a learning process on the value D EV and temperature data D T When operating data other than the above is input, the value D for the expansion valve in the absence of refrigerant leakage EV and temperature data D T It is possible to generate a trained model that infers an index value based on

[0065] (1-2) Processing Next, the flow of the learning process by the control unit 121 in the learning phase will be described. Fig. 8 is an example of a flowchart showing the flow of the learning process by the control unit. Note that, as described above, the learning process shown in Fig. 8 is executed in a state where there is no refrigerant leakage in the refrigerant circuit 110.

[0066] In step S801, the control unit 121 functioning as the learning unit 700 calculates the temperature data D measured by the temperature sensor installed in the path located at a height lower than the average height of the plurality of paths before joining at the outlet of the heat exchanger 300. T are acquired at predetermined intervals.

[0067] In step S802, the control unit 121 functioning as the learning unit 700 calculates the value D EV are acquired at predetermined intervals.

[0068] In step S803, the control unit 121 functioning as the learning unit 700 uses the acquired temperature data D T and the obtained value D for the expansion valve EVBased on this, an index value that is the correct data is calculated.

[0069] In step S804, the control unit 121 functioning as the learning unit 700 calculates the value D EV and temperature data D T Operation data other than the above is acquired as input data.

[0070] In step S805, the control unit 121 functioning as the learning unit 700 generates learning data 711 based on the acquired input data and the calculated correct answer data, and stores the data in the learning data storage unit 710.

[0071] In step S806, the control unit 121 functioning as the learning unit 700 determines whether or not a sufficient amount of learning data has been stored to perform the learning process. If it is determined in step S806 that the amount of learning data is not stored, it determines to continue generating learning data (determined as YES in step S806), and returns to step S801.

[0072] On the other hand, if it is determined in step S806 that the data has been stored, it is determined that the generation of learning data is to be ended (NO in step S806), and the process proceeds to step S807.

[0073] In step S807, the control unit 121 functioning as the learning unit 700 performs a learning process on the learning model 705 using the learning data stored in the learning data storage unit 710 to generate a trained model. As a result, a trained model is generated that infers an index value in the refrigerant circuit 110 in a state where there is no refrigerant leakage.

[0074] In step S808, the control unit 121 functioning as the learning unit 700 stores the generated trained model, and ends the learning process.

[0075] (2) Inference Phase (2-1) Functional configuration Next, the functional configuration of the control unit 121 in the inference phase will be described. Fig. 9 is a diagram showing an example of the functional configuration of the control unit (inference phase).

[0076] As described above, the fault diagnosis program is executed in the inference phase, causing the control unit 121 to function as an inference unit 900. As shown in Fig. 9 , the inference unit 900 includes an expansion valve feature amount acquisition unit 901, a temperature feature amount acquisition unit 902, an index value calculation unit 903, an input data acquisition unit 904, a trained model 905, an abnormality degree calculation unit 906, a leakage determination unit 907, and an output unit 908.

[0077] The expansion valve feature quantity acquisition unit 901 acquires a value D relating to the expansion valve as operation data in the refrigeration cycle. EV As described above, the value D relating to the expansion valve is acquired at predetermined intervals. EV The expansion valve characteristic amount acquisition unit 901 acquires a value D EV are notified to the index value calculation unit 903 in sequence.

[0078] The temperature feature quantity acquisition unit 902 acquires, as operational data in the refrigeration cycle, temperature data D measured by a temperature sensor installed in a path located at a height lower than the average height of the multiple paths before joining at the outlet of the heat exchanger 300. T As described above, the temperature sensors installed on paths located at heights lower than the average height of the plurality of paths are, for example, the temperature sensors 344 to 346. The temperature feature quantity acquisition unit 902 acquires the temperature data D acquired at predetermined intervals. T are notified to the index value calculation unit 903 in sequence.

[0079] The index value calculation unit 903 calculates the value D relating to the expansion valve notified by the expansion valve feature amount acquisition unit 901. EV and the temperature data D notified from the temperature feature amount acquisition unit 902 T When the above is input, an index value is calculated and notified to the abnormality degree calculation unit 906.

[0080] The input data acquisition unit 904 acquires a value D related to the expansion valve in the refrigeration cycle. EV and temperature data D T Other operational data, such as condensation temperature, evaporation temperature, compressor rotation speed, outside air temperature, degree of superheat, etc., are acquired as input data at predetermined intervals.

[0081] The trained model 905 is a trained model generated by the learning unit 700 in the learning phase. The trained model 905 receives input data acquired by the input data acquisition unit 904. As a result, the trained model 905 infers an index value in the refrigerant circuit 110 in a state where there is no refrigerant leakage, and notifies the abnormality degree calculation unit 906.

[0082] The anomaly degree calculation unit 906 compares the index value notified from the trained model 905 with the index value notified from the index value calculation unit 903, and calculates the difference value (anomaly degree) between them. The anomaly degree calculation unit 906 notifies the leak determination unit 907 of the calculated difference value.

[0083] The leakage determination unit 907 determines whether the difference value notified by the abnormality degree calculation unit 906 is less than a predetermined threshold. If it is less than the predetermined threshold, the leakage determination unit 907 determines that refrigerant is not leaking in the refrigerant circuit 110, and if it is equal to or greater than the predetermined threshold, the leakage determination unit 907 determines that refrigerant is leaking in the refrigerant circuit 110. In addition, the leakage determination unit 907 notifies the output unit 908 of the determination result.

[0084] When the determination result notified by the leakage determination unit 907 indicates that the refrigerant is leaking, the output unit 908 notifies that the refrigerant is leaking.

[0085] (2-2) Processing Next, a description will be given of the flow of the refrigerant leakage determination process by the control unit 121 in the inference phase. Fig. 10 is an example of a flowchart showing the flow of the refrigerant leakage determination process by the control unit.

[0086] In step S1001, the control unit 121 functioning as the inference unit 900 calculates the temperature data D measured by the temperature sensor installed in the path located at a height lower than the average height of the plurality of paths before joining at the outlet of the heat exchanger 300. T are acquired at predetermined intervals.

[0087] In step S1002, the control unit 121 functioning as the inference unit 900 calculates the value D EV are acquired at predetermined intervals.

[0088] In step S1003, the control unit 121 functioning as the inference unit 900 calculates the temperature data D T and the obtained value D for the expansion valve EV Based on the above, the index value calculation unit 903 calculates an index value.

[0089] In step S1004, the control unit 121 functioning as the inference unit 900 calculates the value D EV and temperature data D T Operation data other than the above is acquired as input data.

[0090] In step S1005, the control unit 121 functioning as the inference unit 900 inputs the acquired input data into the trained model, thereby estimating the index value in the refrigerant circuit 110 in a state where there is no refrigerant leakage.

[0091] In step S1006, the control unit 121 functioning as the inference unit 900 determines whether the difference between the index value calculated in step S1003 and the index value estimated in step S1005 is less than a predetermined threshold value. If it is determined in step S1006 that the difference is less than the predetermined threshold value (YES in step S1006), the process proceeds to step S1008.

[0092] On the other hand, if it is determined in step S1006 that the value is equal to or greater than the predetermined threshold value (NO in step S1006), the process proceeds to step S1007.

[0093] In step S1007, the control unit 121 functioning as the inference unit 900 determines that refrigerant is leaking in the refrigerant circuit 110, and issues a notification that refrigerant is leaking.

[0094] In step S1008, the control unit 121 functioning as the inference unit 900 determines whether or not to continue the refrigerant leakage determination process. If it is determined in step S1008 that the refrigerant leakage determination process should be continued (YES in step S1008), the process returns to step S1001.

[0095] On the other hand, if it is determined in step S1008 that the refrigerant leakage determination process should not be continued (NO in step S1008), the refrigerant leakage determination process ends.

[0096] <Specific examples of index values ​​for each refrigerant circuit> Next, specific examples of index values ​​used in refrigeration cycle systems having various types of refrigerant circuits will be described. Note that in the various types of refrigerant circuits shown below, the direction of the arrow indicating the refrigerant flow represents the direction when cooling operation is being performed.

[0097] (1) First refrigerant circuit Fig. 11 is a diagram showing a specific example of index values ​​used in a refrigeration cycle system having a first refrigerant circuit. As shown in Fig. 11, a first refrigerant circuit 1100 includes a compressor 1101, a condenser 1102, an expansion valve 1103, and an evaporator 1104. The expansion valve 1103 is installed between the outlet of the condenser 1102 and the inlet of the evaporator 1104.

[0098] The first refrigerant circuit 1100 also includes a temperature sensor 1111 (compressor discharge pipe temperature sensor), a temperature sensor 1112 (high-pressure side heat exchanger inlet gas pipe temperature sensor), and a pressure sensor 1113 (high-pressure side pressure sensor).The first refrigerant circuit 1100 also includes a temperature sensor 1114 and a temperature sensor 1115 (high-pressure side heat exchanger outlet liquid pipe temperature sensor).

[0099] The temperature sensor 1114 is a temperature sensor installed in the path before the merging at the outlet of the heat exchanger in the condenser 1102 (the path located at a height lower than the average value).

[0100] When determining whether or not there is a refrigerant leak in the first refrigerant circuit 1100, the control unit 121 determines a value D EV and temperature data D T Specifically, the control unit 121 calculates the index value using the following: Value D for expansion valve EV Any one of the opening degree of the expansion valve 1103, the refrigerant flow rate ratio, the CV value, and the cooling capacity calculated based on the opening degree of the expansion valve 1103, Temperature data D measured by a temperature sensor installed in the path before the junction at the heat exchanger outlet (path located at a height lower than the average value) T : Temperature data measured by the temperature sensor 1114, The index value is calculated by obtaining the above.

[0101] (2) Second refrigerant circuit Fig. 12 is a diagram showing a specific example of index values ​​used in a refrigeration cycle system having a second refrigerant circuit. As shown in Fig. 12, the second refrigerant circuit 1200 is a refrigerant circuit for a chiller, and includes a compressor 1201, a condenser 1202, and an economizer circuit 1203. The economizer circuit 1203 includes an economizer heat exchanger 1203_1 and an economizer heat exchanger expansion valve 1203_2. The expansion valve 1204 is installed between the outlet of the condenser 1202 and the inlet of the evaporator 1205.

[0102] The second refrigerant circuit 1200 also includes an expansion valve 1204 , an evaporator 1205 , an indoor heat exchanger 1206 , and a pump 1207 .

[0103] The second refrigerant circuit 1200 also includes a temperature sensor 1211 (compressor discharge pipe temperature sensor), a temperature sensor 1212 (high-pressure side heat exchanger inlet gas pipe temperature sensor), a temperature sensor 1213, and a temperature sensor 1214 (high-pressure side heat exchanger outlet liquid pipe temperature sensor). The temperature sensor 1213 is a temperature sensor installed in a path (a path located at a height lower than the average) before the merging at the heat exchanger outlet in the condenser 1202.

[0104] The second refrigerant circuit 1200 also includes a temperature sensor 1215 (economizer outlet (bypass side) temperature sensor), a temperature sensor 1216, and a pressure sensor 1221 (high-pressure side pressure sensor). The temperature sensor 1216 is a temperature sensor installed in a path (a path located at a height lower than the average) before the merging at the economizer heat exchanger outlet.

[0105] When determining whether or not there is a refrigerant leak in the second refrigerant circuit 1200, the control unit 121 determines a value D EV and temperature data D T Specifically, the control unit 121 calculates the index value using the following: Value D for expansion valve EV : Cooling capacity calculated based on the opening of the expansion valve 1204, the refrigerant flow rate ratio, the CV value, and the opening of the expansion valve 1204, Temperature data D measured by a temperature sensor installed in the path before the junction at the heat exchanger outlet (path located at a height lower than the average value) T : temperature data measured by the temperature sensor 1216, The index value is calculated by obtaining the above.

[0106] Alternatively, the control unit 121 Value D for expansion valve EV : cooling capacity calculated based on the opening degree of the economizer heat exchange expansion valve 1203_2, the refrigerant flow rate ratio, the CV value, and the opening degree of the economizer heat exchange expansion valve 1203_2, Temperature data D measured by a temperature sensor installed in the path before the junction at the heat exchanger outlet (path located at a height lower than the average value) T: Temperature data measured by the temperature sensor 1213, The index value is calculated by obtaining the above.

[0107] (3) Third refrigerant circuit Fig. 13 is a diagram showing a specific example of index values ​​used in a refrigeration cycle system having a third refrigerant circuit. As shown in Fig. 13, the third refrigerant circuit 1300 is a refrigerant circuit for a multi-air conditioner for a building, and includes a compressor 1301, a four-way valve 1302, a condenser 1303, a condenser outlet expansion valve 1304, and a subcooling circuit 1305. The subcooling circuit 1305 includes a subcooling heat exchanger 1305_1 and a subcooling heat exchanger expansion valve 1305_2. The condenser outlet expansion valve 1304 is installed between the outlet of the condenser 1303 and the inlets of the evaporators 1307_1 to 1307_n.

[0108] The third refrigerant circuit 1300 includes evaporator inlet expansion valves 1306_1 to 1306_n, evaporators 1307_1 to 1307_n, and an accumulator 1308. The evaporator inlet expansion valves 1306_1 to 1306_n are installed between the outlet of the condenser 1303 and the inlets of the evaporators 1307_1 to 1307_n.

[0109] The third refrigerant circuit 1300 also includes a temperature sensor 1311 (compressor discharge pipe temperature sensor), a temperature sensor 1312 (high-pressure side heat exchanger inlet gas pipe temperature sensor), a temperature sensor 1313, a temperature sensor 1314 (high-pressure side heat exchanger outlet liquid pipe temperature sensor), and a temperature sensor 1315. The temperature sensor 1313 is a temperature sensor installed in a path (a path located at a height lower than the average) before the merging at the heat exchanger outlet in the condenser 1303. The temperature sensor 1315 is a temperature sensor installed in a path (a path located at a height lower than the average) before the merging at the outlet of the subcooling heat exchanger 1305_1.

[0110] The third refrigerant circuit 1300 also includes a temperature sensor 1316 (a subcooling heat exchanger outlet gas pipe temperature sensor) and a pressure sensor 1321 (a high-pressure side pressure sensor).

[0111] When determining whether or not there is a refrigerant leak in the third refrigerant circuit 1300, the control unit 121 determines a value D EV and temperature data D T Specifically, the control unit 121 calculates the index value using the following: Value D for expansion valve EV : Cooling capacity calculated based on the opening degree of the evaporator inlet expansion valves 1306_1 to 1306_n, the refrigerant flow rate ratio, the CV value, and the opening degree of the evaporator inlet expansion valves 1306_1 to 1306_n, Temperature data D measured by a temperature sensor installed in the path before the junction at the heat exchanger outlet (path located at a height lower than the average value) T : temperature data measured by the temperature sensor 1315, The index value is calculated by obtaining the above.

[0112] Alternatively, the control unit 121 Value D for expansion valve EV : cooling capacity calculated based on the opening degree of the subcooling heat exchange expansion valve 1305_2, the refrigerant flow rate ratio, the CV value, and the opening degree of the subcooling heat exchange expansion valve 1305_2, Temperature data D measured by a temperature sensor installed in the path before the junction at the heat exchanger outlet (path located at a height lower than the average value) T : Temperature data measured by the temperature sensor 1313, The index value is calculated by obtaining the above.

[0113] Alternatively, the control unit 121 Value D for expansion valve EV : cooling capacity calculated based on the opening degree of the condenser outlet expansion valve 1304, the refrigerant flow rate ratio, the CV value, and the opening degree of the condenser outlet expansion valve 1304, Temperature data D measured by a temperature sensor installed in the path before the junction at the heat exchanger outlet (path located at a height lower than the average value) T : Temperature data measured by the temperature sensor 1313, The index value is calculated by obtaining the above.

[0114] <Specific example of refrigerant leak detection process> Next, a specific example of the refrigerant leakage determination process performed by the control unit 121 will be described. Fig. 14 is a diagram showing a specific example of the refrigerant leakage determination process performed by the control unit.

[0115] 14, the horizontal axis of graph 1400 represents date and time, and the vertical axis represents the difference value (degree of abnormality) of the index value. Note that the difference value (degree of abnormality) of the index value is a difference value calculated by the degree of abnormality calculation unit 906 based on the index value notified from the trained model 905 and the index value notified from the index value calculation unit 903.

[0116] Also, the broken line 1401 is An index value notified from the trained model 905 that has undergone a training process using the index value used in the refrigeration cycle system 100 according to the first embodiment; and An index value notified from the index value calculation unit 903 that calculates an index value used in the refrigeration cycle system 100 according to the first embodiment, and The difference value (degree of abnormality) at each date and time is calculated by the abnormality degree calculation unit 906 based on the above.

[0117] On the other hand, the broken line 1402 is -Indicator values ​​notified from a trained model that has undergone training using conventional indicator values, The index value notified from the index value calculation unit that calculates the conventional index value, The difference value (degree of abnormality) at each date and time is calculated by the abnormality degree calculation unit based on the above.

[0118] As is clear from a comparison between the polygonal lines 1401 and 1402 in FIG. 14, when there is no refrigerant leakage in the refrigerant circuit 110 (refrigerant amount = 100%), both the polygonal lines 1401 and 1402 show small values.

[0119] On the other hand, in the state where there is refrigerant leakage in the refrigerant circuit 110 (refrigerant amount=90%), the polygonal line 1401 indicates a large value, while the polygonal line 1402 remains at a small value. In other words, the index value used in the refrigeration cycle system 100 according to the first embodiment makes it easy to determine refrigerant leakage, which was difficult to determine using conventional index values.

[0120] <Summary> As is clear from the above description, the fault diagnosis system 120 provided in the refrigeration cycle system 100 according to the first embodiment has a control unit 121. · Acquire driving data. The presence or absence of a refrigerant leak is determined using values ​​related to the expansion valve included in the acquired operating data and values ​​measured by a temperature sensor installed in one of the multiple paths before the merging at the heat exchanger outlet. Note that one of the multiple paths before the merging at the heat exchanger outlet includes a path located at a height lower than the average height of the multiple paths.

[0121] As a result, according to the first embodiment, in the refrigeration cycle system 100, it is possible to improve the accuracy of determination when determining the presence or absence of refrigerant leakage from the index value based on the operation data.

[0122] [Second embodiment] In the first embodiment, the temperature data D used to calculate the index value T In the above description, the temperature data measured by the temperature sensors 344 to 346 installed on the paths 334 to 336 located at a height lower than the average height of the plurality of paths is used.

[0123] However, the temperature data D used to calculate the index value T For example, temperature data measured by one or more of the temperature sensors 342 to 346, excluding the temperature sensor 341 installed on the path 331 located at the highest position, may be used as the temperature data.

[0124] Alternatively, the temperature data D used to calculate the index value T For example, temperature data measured by a temperature sensor installed on the path 336 located at the bottom may be used as the temperature data.

[0125] Alternatively, the temperature data D used to calculate the index value T For example, temperature data measured by a temperature sensor installed in a path before the junction at the outlet of the heat exchanger (300) that has a lower temperature than the temperature of the path after the junction may be used as the temperature data.

[0126] Furthermore, in the first embodiment, details of calculating the index value using the temperature data measured by the temperature sensors 344 to 346 were not mentioned, but the index value may be calculated using the sum of the temperature data measured by the temperature sensors 344 to 346. Alternatively, the index value may be calculated using a value (for example, an average value, a median value, a maximum value, etc.) obtained by statistically processing the temperature data measured by the temperature sensors 344 to 346.

[0127] In the first embodiment, the temperature data D used to calculate the index value T In the above description, temperature sensors 344-346 are newly installed in paths 334-336 that are located at heights lower than the average height of the paths in order to measure the index value. However, in a refrigerant circuit in which a defrost sensor for detecting frost formation is previously installed, the index value may be calculated using temperature data measured by the defrost sensor.

[0128] Although the index value described in the first embodiment is used in the refrigeration cycle during low load operation, it may also be used in the refrigeration cycle during medium load operation or high load operation. Alternatively, the index value described in the first embodiment may be configured to be calculated only in the case of low load operation or to be used for determination only in the case of low load operation.

[0129] In the first embodiment, the value D relating to the expansion valve used to calculate the index value in the second refrigerant circuit 1200 and the third refrigerant circuit 1300 is EV and temperature data D T However, in the second refrigerant circuit 1200 and the third refrigerant circuit 1300, the value D EV and temperature data D T The combinations are not limited to those exemplified in the first embodiment.

[0130] In the first embodiment, the index values ​​when the cooling operation is performed in the first refrigerant circuit 1100 to the third refrigerant circuit 1300 are described. However, the index values ​​when the heating operation is performed are similarly described. Value D for expansion valve EV , Temperature data D measured by a temperature sensor installed in the path before the junction at the outlet of the heat exchanger functioning as a condenser (the path located at a height lower than the average height of multiple paths) T , shall be used.

[0131] Although the embodiments 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 claims. [Explanation of symbols]

[0132] 10:Air conditioner 100: Refrigeration cycle system 110: Refrigerant circuit 120: Fault diagnosis system 121: Control unit 300: Heat exchanger 310: Path junction 320: Path branching section 331~336: Pass 341~346: Temperature sensor 350: Temperature sensor 400: Expansion valve 700: Learning Department 701: Expansion valve feature acquisition unit 702: Temperature feature acquisition unit 703: Index value calculation unit 704: Input data acquisition unit 705: Learning Model 900: Reasoning part 901: Expansion valve feature acquisition unit 902: Temperature feature acquisition unit 903: Index value calculation unit 904: Input data acquisition unit 905: Trained model 906: Abnormality calculation unit 907: Leakage detection unit 908: Output section

Claims

1. A fault diagnosis system (120) having a control unit (121), The control unit (121) Acquire driving data, determining whether or not there is a refrigerant leak using a value related to the expansion valve (400) included in the acquired operating data and a value measured by a temperature sensor installed in one of the paths (331 to 336) before merging at the outlet of the heat exchanger (300); Any of the paths (331 to 336) before joining at the outlet of the heat exchanger (300) includes a path (334 to 336) located at a height lower than the average height of the paths. A fault diagnosis system (120).

2. A temperature sensor installed in any one of the paths (331 to 336) before joining at the outlet of the heat exchanger (300) is a defrost sensor for detecting frost formation. The fault diagnosis system (120) of claim 1.

3. Any of the paths (331 to 336) before joining at the outlet of the heat exchanger (300) includes a path (336) arranged at the bottom of the multiple paths arranged in the vertical direction. The fault diagnosis system (120) of claim 1.

4. The value related to the expansion valve (400) includes any one of an opening degree of the expansion valve, a refrigerant flow rate ratio, a CV value of the expansion valve, and a cooling capacity calculated based on the opening degree of the expansion valve. The fault diagnosis system (120) of claim 1.

5. The expansion valve (400) includes any one of a condenser outlet expansion valve, a subcooling heat exchange expansion valve, an economizer heat exchange expansion valve, and an evaporator inlet expansion valve. The fault diagnosis system (120) of claim 1.

6. The expansion valve (400) is installed between the outlet of the condenser and the inlet of the evaporator in the refrigerant circuit (110). The fault diagnosis system (120) of claim 1.

7. A refrigeration cycle system (100) comprising a fault diagnosis system (120) according to any one of claims 1 to 6.

8. A fault diagnosis method for a refrigeration cycle system (100), comprising: acquiring operational data; and determining whether or not there is a refrigerant leak using a value related to the expansion valve (400) included in the acquired operating data and a value measured by a temperature sensor installed in one of the paths (331 to 336) before joining at the outlet of the heat exchanger (300), Any of the paths (331 to 336) before joining at the outlet of the heat exchanger (300) includes a path (334 to 336) located at a height lower than the average height of the paths. Fault diagnosis method.

9. A control unit (121) of the fault diagnosis system acquiring operational data; a step of determining whether or not there is a refrigerant leak using a value related to the expansion valve (400) included in the acquired operating data and a value measured by a temperature sensor installed in one of the paths (331 to 336) before joining at the outlet of the heat exchanger (300); Any of the paths (331 to 336) before joining at the outlet of the heat exchanger (300) includes a path (334 to 336) located at a height lower than the average height of the paths. Fault diagnosis program.

10. An air conditioner (10) comprising the refrigeration cycle system (100) according to claim 7.

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