Heat exchanger clogging fault diagnosis method of thermal management system and thermal management system thereof

Abstract

This invention discloses a method for diagnosing heat exchanger fouling faults in a thermal management system and the corresponding thermal management system. It relates to the technical field of thermal management systems and their control methods. The method includes issuing a heat exchanger fouling fault warning signal when the following conditions are met: the compressor offset value is greater than a preset first threshold, or the real-time operating data of the compressor has reached the maximum allowable value for the compressor; and the fan offset value is greater than a preset second threshold, or the real-time operating data of the fan has reached the maximum allowable value for the fan. This invention primarily addresses the problem of providing a method for diagnosing heat exchanger fouling faults in a thermal management system. This invention can provide early diagnosis and warning of heat exchanger fouling faults in a thermal management system without relying on complex algorithms, high-end sensors, or maintenance by operators, thus saving significant economic costs and energy consumption, and preventing further escalation of thermal management system faults.

Description

Technical Field

[0001] This invention relates to the technical field of thermal management systems and their control methods, specifically to a method for diagnosing heat exchanger blockage faults in a thermal management system and the thermal management system thereof. Background Technology

[0002] An energy storage system is a system used to store and release electrical energy. It involves the conversion between electrical energy and chemical energy, as well as the conversion between different types of electrical energy. In these processes, a lot of heat is generated. If the heat cannot be dissipated in time, the temperature of the energy storage system will rise, posing safety hazards and affecting the performance, lifespan, and normal operation of the energy storage system.

[0003] In order to control the temperature of the energy storage system and improve its charging and discharging efficiency, a thermal management system needs to be configured in the energy storage system to dissipate heat. Among them, the heat dissipation system using phase change refrigeration technology is the most widely used thermal management system solution.

[0004] A heat dissipation system employing phase change refrigeration technology typically includes a compressor, condenser, expansion valve, evaporator, and refrigerant piping connecting these components. Condensers (e.g., air condensers and water condensers) and evaporators (e.g., air-cooled evaporators, direct-cooling evaporative heat exchangers that exchange heat directly with the energy storage system, and evaporative heat exchangers that exchange heat with the liquid cooling medium in liquid-cooled units) are all heat exchangers within a thermal management system. Therefore, heat exchangers are one of the core components in various thermal management systems.

[0005] After the thermal management system has been running for a period of time, the heat exchangers mentioned above are likely to become clogged (e.g., dust or oil buildup), which will obviously affect the heat exchange performance of the heat exchangers, thereby affecting the overall efficiency of the thermal management system and causing performance degradation and shutdown of the thermal management system and energy storage system.

[0006] In existing thermal management systems, identifying heat exchanger blockage faults usually requires manual intervention, relying on observation and experience for judgment. This obviously consumes a lot of labor costs, is inefficient, and has a high error rate and delay rate.

[0007] In conclusion, how to provide a high-efficiency, objective, and accurate method for diagnosing heat exchanger blockage faults in thermal management systems without relying on manual intervention has become an urgent problem to be solved. Summary of the Invention

[0008] The purpose of this invention is to provide a method for diagnosing heat exchanger blockage faults in a thermal management system and a thermal management system thereof, which is characterized by high efficiency, objectivity, high accuracy and no need for manual intervention.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a method for diagnosing heat exchanger blockage in a thermal management system, wherein the thermal management system is used to dissipate heat for functional devices; the thermal management system includes a compressor, a condenser with a fan, an expansion valve, and an evaporator; the refrigerant passages of the compressor, the condenser, the expansion valve, and the evaporator are sequentially connected, so that the refrigerant can circulate among the refrigerant passages of the compressor, the condenser, the expansion valve, and the evaporator;

[0010] The method includes:

[0011] S1. After the thermal management system is put into operation, it collects several sets of ambient temperature data, functional device operating condition data, compressor operating condition data and fan operating condition data.

[0012] S2. Using the ambient temperature data and the operating condition data of the functional device as independent variables, and the operating condition data of the compressor and the operating condition data of the fan as dependent variables, a cooling capacity reference model is established.

[0013] S3. After the cooling capacity reference model is established, during the operation of the thermal management system, real-time data of ambient temperature, real-time data of functional device operation status, real-time data of compressor operation status, and real-time data of fan operation status are collected in real time / intermittently.

[0014] S4. Input the real-time ambient temperature data and the real-time operating condition data of the functional device as input data into the cooling capacity reference model to obtain the compressor operating condition reference data and fan operating condition reference data output by the cooling capacity reference model.

[0015] S5. Calculate the offset value between the real-time operating data of the compressor and the reference data of the compressor, and record it as the compressor offset value. Also, calculate the offset value between the real-time operating data of the fan and the reference data of the fan, and record it as the fan offset value.

[0016] S6. When the real-time operating data of the compressor, the real-time operating data of the fan, the compressor offset value, and the fan offset value meet the following conditions, a heat exchanger blockage fault warning signal is issued:

[0017] The compressor offset value is greater than a preset first threshold, or the real-time operating data of the compressor has reached the maximum value allowed by the compressor.

[0018] Furthermore, the fan offset value is greater than a preset second threshold, or the real-time operating data of the fan has reached the maximum value allowed by the fan;

[0019] S7. Repeat steps S3-S6.

[0020] In the above technical solution, the functional device is a battery pack in the energy storage system; the operating condition data of the functional device and the real-time operating condition data of the functional device are both the heat generation (kW) of the battery pack in the energy storage system.

[0021] In the above technical solution, the compressor operating condition data, the real-time compressor operating condition data, and the compressor operating condition reference data are all the compressor frequency (Hz).

[0022] In the above technical solution, the cooling capacity reference model includes a compressor operating condition reference sub-model; the compressor operating condition reference sub-model is specifically a regression model that uses the ambient temperature data and the functional device operating condition data as independent variables and the compressor operating condition data as the dependent variable.

[0023] In the above technical solution, the compressor offset value in step S5 is specifically as follows:

[0024]

[0025] Wherein, Δf is the difference between the real-time operating data of the compressor and the reference operating data of the compressor.

[0026] In the above technical solution, in step S6, the compressor offset value is greater than a preset first threshold. The specific judgment method is: the compressor offset value > 20%.

[0027] In the above technical solution, the fan operating condition data, the real-time fan operating condition data, and the fan operating condition reference data are all the fan speed percentage (%).

[0028] In the above technical solution, the cooling capacity reference model includes a fan operating condition reference sub-model; the fan operating condition reference sub-model is specifically a regression model that uses the ambient temperature data and the functional device operating condition data as independent variables and the fan operating condition data as the dependent variable.

[0029] In the above technical solution, in step S5, the fan offset value is specifically: fan offset value (%) = real-time data of fan operating conditions (%) - reference data of fan operating conditions (%); in step S6, the fan offset value is greater than a preset threshold, and the specific judgment method is: fan offset value (%) > 30%.

[0030] A thermal management system that applies the above-mentioned heat exchanger clogging fault diagnosis method of the thermal management system.

[0031] Compared with existing technologies, the beneficial effects of this invention are as follows: The heat exchanger fouling fault diagnosis method and thermal management system of this invention, by collecting ambient temperature data, functional device operating condition data, compressor operating condition data, and fan operating condition data, establishes a cooling capacity reference model. During the subsequent operation of the thermal management system, real-time / intermittent data of ambient temperature, functional device operating condition, compressor operating condition, and fan operating condition are collected and compared with the compressor operating condition reference data and fan operating condition reference data output by the cooling capacity reference model, thereby providing early warning of heat exchanger fouling faults in the thermal management system. The heat exchanger fouling fault diagnosis method and thermal management system of this invention can provide early diagnosis and warning of heat exchanger fouling faults in the thermal management system without relying on complex algorithms, high-end sensors, and maintenance by operators, thus saving significant economic costs and energy consumption, and preventing further expansion of thermal management system faults. Attached Figure Description

[0032] Figure 1 This is a system structure view of the thermal management system in this invention.

[0033] Figure 2 This is a flowchart illustrating the steps of the heat exchanger clogging fault diagnosis method for the thermal management system of the present invention.

[0034] The attached diagram is labeled as follows: 1. Compressor; 2. Condenser; 3. Fan; 4. Expansion valve; 5. Evaporator; 10. Functional device. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] This embodiment provides a method for diagnosing heat exchanger blockage faults in a thermal management system. It can be applied to the thermal management system to provide early diagnosis and warning of heat exchanger blockage faults.

[0037] The thermal management system is used to dissipate heat from functional device 10; please refer to Figure 1 Specifically, the thermal management system includes a compressor 1, a condenser 2 with a fan 3, an expansion valve 4, and an evaporator 5 adapted to exchange heat with the functional device 10.

[0038] Among them, the compressor 1 is the compressor 1 used to compress the refrigerant in the refrigeration system, specifically the variable frequency compressor 1; the condenser 2 is the condenser used to condense the refrigerant in the refrigeration system, which dissipates heat through its own attached fan 3. It should be noted that the fan 3 is a precision electronic fan, which is controlled by the host computer and can at least feed back its speed (rpm) or speed percentage (%) to the host computer; the expansion valve 4 is the expansion valve 4 used to throttle the refrigerant in the refrigeration system, specifically the electronic expansion valve.

[0039] It should be noted that the evaporator 5 is used in the refrigeration system to supply the refrigerant for evaporation, thereby absorbing heat. In some possible embodiments, the heat exchange method between the evaporator 5 and the functional device 10 is liquid cooling, that is, the heat of the functional device 10 is absorbed by the liquid cooling medium in the liquid cooling unit, and the heat of the liquid cooling medium is absorbed by the evaporator 5 in this embodiment. In other possible embodiments, the heat exchange method between the evaporator 5 and the functional device 10 is air cooling, for example, the evaporator 5 in this embodiment is used as the evaporator 5 in the indoor unit of a precision air conditioner in a computer room. In still some possible embodiments, the heat exchange method between the evaporator 5 and the functional device 10 is direct cooling, that is, the evaporator 5 is integrated in a heat exchanger, which is directly attached to the functional device 10, so that the evaporator 5 and the functional device 10 directly exchange heat.

[0040] The refrigerant passages of compressor 1, condenser 2, expansion valve 4 and evaporator 5 are connected in sequence, so that the refrigerant can circulate among the refrigerant passages of compressor 1, condenser 2, expansion valve 4 and evaporator 5. With this setting, the refrigeration function of the thermal management system can be realized.

[0041] It is understood that the thermal management system or its host system includes at least a control device, such as a programmable logic controller, an embedded system, or an industrial control computer.

[0042] It should be noted that both the condenser 2 and the evaporator 5 mentioned above are heat exchangers. The heat exchanger clogging fault diagnosis method of the thermal management system in this embodiment can be used to diagnose clogging faults of either the condenser 2 or the evaporator 5, or it can be used to diagnose clogging faults of both the condenser 2 and the evaporator 5 at the same time.

[0043] Please see Figure 2 The heat exchanger clogging fault diagnosis method of the thermal management system in this embodiment includes:

[0044] S1. After the thermal management system is put into operation, it collects several sets of ambient temperature data, functional device operating condition data, compressor operating condition data, and fan operating condition data.

[0045] S2. Using ambient temperature data and functional device operating condition data as independent variables, and compressor operating condition data and fan operating condition data as dependent variables, establish a cooling capacity reference model.

[0046] S3. After the cooling capacity reference model is established, during the operation of the thermal management system, real-time data of ambient temperature, real-time data of functional device operating conditions, real-time data of compressor operating conditions, and real-time data of fan operating conditions are collected in real time / intermittently.

[0047] S4. Input the real-time ambient temperature data and the real-time operating condition data of the functional devices into the cooling capacity reference model to obtain the compressor operating condition reference data and fan operating condition reference data output by the cooling capacity reference model.

[0048] S5. Calculate the offset between the real-time operating data of the compressor and the reference data of the compressor, and record it as the compressor offset value. Also, calculate the offset between the real-time operating data of the fan and the reference data of the fan, and record it as the fan offset value.

[0049] S6. When the real-time operating data of the compressor, the real-time operating data of the fan, the compressor offset value, and the fan offset value meet the following conditions, a heat exchanger blockage fault warning signal will be issued:

[0050] The compressor offset value is greater than the preset first threshold, or the real-time operating data of the compressor has reached the maximum value allowed by the compressor;

[0051] Furthermore, the fan offset value is greater than the preset second threshold, or the real-time data of the fan's operating condition has reached the maximum value allowed by the fan;

[0052] S7. Repeat steps S3-S6.

[0053] When the compressor and fan in the thermal management system meet the conditions described in step S6, it indicates that the current cooling capacity of the thermal management system is higher than the reference values ​​(compressor operating condition reference data and fan operating condition reference data). The thermal management system may have experienced a heat exchanger blockage fault. The operators of the energy storage system / thermal management system can focus on checking and eliminating the above fault.

[0054] It is understandable that the acquisition of ambient temperature data and real-time ambient temperature data can be achieved by temperature sensors installed near the system or in the computer room / chassis. The temperature sensors connect to the host computer (i.e., the control device) through analog output interfaces or communication interfaces, thereby enabling the acquisition and transmission of ambient temperature data and real-time ambient temperature data.

[0055] Specifically, the functional device is the battery pack in the energy storage system; the operating condition data and real-time operating condition data of the functional device are both the heat generation (kW) of the battery pack in the energy storage system; in fact, the heat generation (kW) of the battery pack can be obtained from the operating condition heat generation data table provided by the battery pack manufacturer, or it can be calculated using physical quantities such as the input power, output power, input current and output current of the battery pack, or it can be collected and transmitted using temperature sensors at the battery pack.

[0056] Specifically, the compressor operating condition data, the real-time compressor operating condition data, and the compressor operating condition reference data are all based on the compressor's frequency (Hz).

[0057] In fact, the compressor frequency (Hz) can be obtained directly by the control device based on the operating information fed back from the compressor's signal line, or it can be calculated using physical quantities such as the compressor's input power, output power, input current, and output current.

[0058] Specifically, the cooling capacity reference model includes a compressor operating condition reference sub-model; the compressor operating condition reference sub-model is a regression model that uses ambient temperature data and functional device operating condition data as independent variables and compressor operating condition data as the dependent variable.

[0059] In fact, by using computer mathematical software, inputting several sets of ambient temperature data (as independent variables), functional device operating condition data (as independent variables), and compressor operating condition data (as dependent variables), and performing linear or nonlinear fitting based on the actual operating characteristics of the thermal management system, a reference sub-model of compressor operating conditions can be obtained.

[0060] In step S5, the compressor offset value is specifically as follows:

[0061]

[0062] Where Δf is the difference between the real-time operating data of the compressor and the reference operating data of the compressor.

[0063] Specifically, in step S6, the compressor offset value is greater than a preset threshold. The specific judgment method is: compressor offset value > 20%.

[0064] Specifically, the wind turbine operating condition data, real-time wind turbine operating condition data, and wind turbine operating condition reference data are all percentages of wind turbine speed (%).

[0065] It should be noted that the fan speed percentage (%) is specifically the ratio of the fan's current speed to its maximum speed. For example, when the fan's maximum speed is 1000 rpm and the fan's current speed is 500 rpm, then the fan speed percentage is 50%.

[0066] In fact, the fan speed percentage (%) can be directly obtained by the control device based on the operating information fed back from the fan's signal line.

[0067] Specifically, the cooling capacity reference model includes a fan operating condition reference sub-model; the fan operating condition reference sub-model is a regression model that uses ambient temperature data and functional device operating condition data as independent variables and fan operating condition data as the dependent variable.

[0068] In fact, by using computer mathematical software, inputting several sets of ambient temperature data (as independent variables), functional device operating condition data (as independent variables), and fan operating condition data (as dependent variables), and performing linear or nonlinear fitting based on the actual operating characteristics of the thermal management system, a reference sub-model of fan operating conditions can be obtained.

[0069] In step S5, the fan offset value is specifically as follows:

[0070] Fan offset value (%) = Real-time data of fan operating conditions (%) - Reference data of fan operating conditions (%).

[0071] In step S6, the fan offset value is greater than the preset threshold. The specific judgment method is: fan offset value (%) > 30%.

[0072] It should be noted that the real-time operating data of the compressor has reached the maximum value allowed by the compressor. Specifically, the compressor frequency (Hz) has reached / exceeded the maximum value of the frequency (Hz) preset at the factory. The real-time operating data of the fan has reached the maximum value allowed by the fan. Specifically, the fan speed percentage (%) has reached / exceeded 100%.

[0073] The following specific example will further illustrate the technical solution of the present invention:

[0074] In a certain location, an 8kW energy storage system is to be built as needed. The battery pack (i.e., functional device) of the energy storage system uses the thermal management system of this embodiment for heat dissipation.

[0075] The energy storage system has a total of 16 battery clusters, each with a heat output of 0.5kW. Therefore, the full-load heat output of the battery clusters in the energy storage system is 16 × 0.5 = 8kW. That is, when the energy storage system is running at full load, the operating data of the functional device is 8kW. When the load is not full, the operating data of the functional device will be lower than 8kW. The operating data of the functional device can be determined based on the number of battery clusters in operation.

[0076] After the energy storage system and the thermal management system of this embodiment are put into operation, the control device collects several sets of ambient temperature data, functional device operating condition data, compressor operating condition data and fan operating condition data.

[0077] As a typical case of normal operation of the thermal management system, one set of data reflects: the ambient temperature is 35℃, the operating condition of the functional device is 8kW, the operating condition of the compressor is 50Hz, and the operating condition of the fan is 40%.

[0078] Several sets of collected ambient temperature data, functional device operating condition data, and compressor operating condition data are input into computer mathematical software to obtain a compressor operating condition reference sub-model. Similarly, several sets of collected ambient temperature data, functional device operating condition data, and fan operating condition data are input into computer mathematical software to obtain a fan operating condition reference sub-model. The compressor operating condition reference sub-model and the fan operating condition reference sub-model together constitute the cooling capacity reference model.

[0079] During the operation of the energy storage system and the thermal management system of this embodiment, the control device collects real-time data on ambient temperature, operating conditions of functional devices, operating conditions of the compressor, and operating conditions of the fan.

[0080] One set of data reflects that: the real-time ambient temperature is 35℃, the real-time operating status of the functional device is 8kW, the real-time operating status of the compressor is 80Hz, and the real-time operating status of the fan is 100% (that is, the speed has reached the maximum allowable value of the fan).

[0081] Real-time ambient temperature data (35℃) and real-time operating data of functional devices (8kW) are input into the cooling capacity reference model (specifically, into the compressor operating condition reference sub-model and the fan operating condition reference sub-model respectively). The cooling capacity reference model outputs compressor operating condition reference data at 50Hz and fan operating condition reference data at 40% (the same as the typical case data during normal operation mentioned above).

[0082] at this time, If the percentage exceeds 20% of the preset first threshold and the real-time operating data of the fan has reached the maximum value allowed by the fan, it indicates that there is a heat exchanger blockage fault in the thermal management system of this embodiment. The control device issues a heat exchanger blockage fault warning signal through its own interactive device, or the control device issues a heat exchanger blockage fault warning signal to its host computer, so as to warn the operators of the energy storage system or the thermal management system of the heat exchanger blockage fault in the thermal management system.

[0083] This embodiment also provides a thermal management system that applies the above-described method for diagnosing heat exchanger blockage faults in thermal management systems.

[0084] The heat exchanger fouling fault diagnosis method and thermal management system of this embodiment, by collecting ambient temperature data, functional device operating condition data, compressor operating condition data, and fan operating condition data, establishes a cooling capacity reference model. During the subsequent operation of the thermal management system, real-time / intermittent real-time ambient temperature data, functional device operating condition data, compressor operating condition data, and fan operating condition data are collected and compared with the compressor operating condition reference data and fan operating condition reference data output by the cooling capacity reference model, thereby providing early warning of heat exchanger fouling faults in the thermal management system. The heat exchanger fouling fault diagnosis method and thermal management system of this embodiment can provide early diagnosis and warning of heat exchanger fouling faults in the thermal management system without relying on complex algorithms, high-end sensors, and maintenance by operators, thus saving a lot of economic costs and energy consumption, and preventing the further expansion of thermal management system faults.

[0085] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for diagnosing heat exchanger blockage in a thermal management system, wherein the thermal management system is used to dissipate heat for functional devices; The thermal management system includes a compressor, a condenser with a fan, an expansion valve, and an evaporator; The refrigerant passages of the compressor, the condenser, the expansion valve, and the evaporator are connected in sequence, so that the refrigerant can circulate among the refrigerant passages of the compressor, the condenser, the expansion valve, and the evaporator; Its features are, The method includes: S1. After the thermal management system is put into operation, it collects several sets of ambient temperature data, functional device operating condition data, compressor operating condition data and fan operating condition data. S2. Using the ambient temperature data and the operating condition data of the functional device as independent variables, and the operating condition data of the compressor and the operating condition data of the fan as dependent variables, a cooling capacity reference model is established. S3. After the cooling capacity reference model is established, during the operation of the thermal management system, real-time data of ambient temperature, real-time data of functional device operation status, real-time data of compressor operation status, and real-time data of fan operation status are collected in real time / intermittently. S4. Input the real-time ambient temperature data and the real-time operating condition data of the functional device as input data into the cooling capacity reference model to obtain the compressor operating condition reference data and fan operating condition reference data output by the cooling capacity reference model. S5. Calculate the offset value between the real-time operating data of the compressor and the reference data of the compressor, and record it as the compressor offset value. Also, calculate the offset value between the real-time operating data of the fan and the reference data of the fan, and record it as the fan offset value. S6. When the real-time operating data of the compressor, the real-time operating data of the fan, the compressor offset value, and the fan offset value meet the following conditions, a heat exchanger blockage fault warning signal is issued: The compressor offset value is greater than a preset first threshold, or the real-time operating data of the compressor has reached the maximum value allowed by the compressor. Furthermore, the fan offset value is greater than a preset second threshold, or the real-time operating data of the fan has reached the maximum value allowed by the fan; S7. Repeat steps S3-S6; The functional device is a battery pack in an energy storage system; The operating condition data of the functional device and the real-time operating condition data of the functional device are both the heat generation (kW) of the battery pack in the energy storage system. The compressor operating condition data, the real-time compressor operating condition data, and the compressor operating condition reference data are all the compressor frequency (Hz); The cooling capacity reference model includes a compressor operating condition reference sub-model; The compressor operating condition reference sub-model is specifically a regression model that uses the ambient temperature data and the operating condition data of the functional device as independent variables and the compressor operating condition data as the dependent variable. The operating condition data of the fan, the real-time operating condition data of the fan, and the reference operating condition data of the fan are all percentages of the fan speed (%). The cooling capacity reference model includes a fan operating condition reference sub-model; The wind turbine operating condition reference sub-model is specifically a regression model that uses the ambient temperature data and the operating condition data of the functional devices as independent variables, and the wind turbine operating condition data as the dependent variable.

2. The method for diagnosing heat exchanger blockage in a thermal management system according to claim 1, characterized in that, In step S5, the compressor offset value is specifically as follows: Wherein, Δf is the difference between the real-time operating data of the compressor and the reference operating data of the compressor.

3. The method for diagnosing heat exchanger blockage in a thermal management system according to claim 2, characterized in that, In step S6, the compressor offset value is greater than a preset first threshold. The specific determination method is as follows: The compressor offset value is greater than 20%.

4. The method for diagnosing heat exchanger blockage in a thermal management system according to claim 1, characterized in that, In step S5, the fan offset value is specifically: Fan offset value (%) = Real-time data of fan operating conditions (%) - Reference data of fan operating conditions (%); In step S6, the fan offset value is greater than a preset threshold. The specific determination method is as follows: Fan offset value (%) > 30%.

5. A thermal management system, characterized in that, The heat exchanger clogging fault diagnosis method of the thermal management system described in any one of claims 1-4 is applied.

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