Fault diagnosis method and device of heat pump system, heat pump system and storage medium

Abstract

The application relates to the technical field of heat pumps, and discloses a fault diagnosis method for a heat pump system, which comprises the following steps: under the condition that the heat pump system is stably operated, obtaining a first outlet water temperature and a first inlet water temperature of a water circulation loop, and obtaining an exhaust pressure of a refrigerant circulation loop; calculating a difference between a saturation temperature corresponding to the exhaust pressure and the first outlet water temperature to obtain a heat exchange temperature difference; under the condition that the absolute value of the heat exchange temperature difference is greater than a preset temperature difference threshold, adjusting the rotating speed of a water pump; under the condition that the heat pump system is stably operated again, obtaining a second outlet water temperature and a second inlet water temperature of the water circulation loop; and diagnosing whether an outlet water temperature sensor is faulty according to the first outlet water temperature, the first inlet water temperature, the second outlet water temperature and the second inlet water temperature. The application can improve the stability of the operation of the heat pump system and is beneficial to guaranteeing the hot water use experience of users. The application also discloses a fault diagnosis device for the heat pump system, a heat pump system and a storage medium.

Description

Technical Field

[0001] This application relates to the field of heat pump technology, such as a fault diagnosis method, device, heat pump system, and storage medium for a heat pump system. Background Technology

[0002] Currently, in heat pump systems used for hot water production, system regulation often relies on the detection of inlet and outlet water temperatures. One related technology discloses a method for controlling a hot water supply device, comprising: determining the exhaust superheat of the compressor; if the exhaust superheat exceeds a first threshold, determining a control scheme for the hot water supply device based on the outlet water temperature of the heat exchanger and the saturation temperature corresponding to the pressure on the refrigerant side of the heat exchanger; and controlling the hot water supply device to execute the control scheme.

[0003] In the process of implementing the embodiments of this disclosure, at least the following problems were found in the related art:

[0004] The control methods of related technologies rely on the detection of the outlet water temperature of the heat exchanger, thus requiring high accuracy from the outlet water temperature sensor. However, these technologies lack fault monitoring methods for the temperature sensor. If the outlet water temperature sensor malfunctions and fails to measure the temperature accurately, the control of related systems will be affected, which in turn will affect the stability of the heat pump system and compromise the user's hot water experience. Summary of the Invention

[0005] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or describe the scope of protection of these embodiments, but rather as a prelude to the detailed description that follows.

[0006] This disclosure provides a fault diagnosis method, device, heat pump system, and storage medium for a heat pump system, which can improve the stability of the heat pump system operation and help ensure the user's hot water experience.

[0007] In some embodiments, the heat pump system includes a refrigerant circulation loop and a water circulation loop, wherein a water pump is installed in the inlet pipe of the water circulation loop, and an outlet water temperature sensor is installed in the outlet pipe of the water circulation loop; the method includes:

[0008] Under the condition that the heat pump system is operating stably, the first outlet water temperature and the first inlet water temperature of the water circulation loop are obtained, and the exhaust pressure of the refrigerant circulation loop is obtained.

[0009] Calculate the difference between the saturation temperature corresponding to the exhaust pressure and the first outlet water temperature to obtain the heat exchange temperature difference;

[0010] If the absolute value of the heat exchange temperature difference is greater than the preset temperature difference threshold, adjust the speed of the water pump;

[0011] Once the heat pump system is running stably again, obtain the second outlet water temperature and the second inlet water temperature of the water circulation loop.

[0012] Based on the first outlet water temperature, the first inlet water temperature, the second outlet water temperature, and the second inlet water temperature, diagnose whether the outlet water temperature sensor is malfunctioning.

[0013] In some embodiments, the apparatus includes a processor and a memory storing program instructions, the processor being configured to execute the above-described fault diagnosis method for a heat pump system when the program instructions are executed.

[0014] In some embodiments, the heat pump system includes:

[0015] The refrigerant circulation loop consists of a compressor, a four-way valve, an indoor heat exchanger, a throttling device, and an outdoor heat exchanger connected by refrigerant piping.

[0016] The water circulation loop is composed of an inlet pipe, the indoor heat exchanger, and an outlet pipe. The inlet pipe is equipped with a water pump, and the outlet pipe is equipped with an outlet water temperature sensor.

[0017] The above-mentioned fault diagnosis device for heat pump systems.

[0018] In some embodiments, the storage medium stores program instructions that, when executed, perform the above-described fault diagnosis method for the heat pump system.

[0019] The fault diagnosis method, apparatus, heat pump system, and storage medium for heat pump systems provided in this disclosure can achieve the following technical effects:

[0020] In this embodiment, under stable operation of the heat pump system, the difference between the outlet water temperature of the heat exchanger and the saturation temperature corresponding to the refrigerant side exhaust pressure is first compared to determine the heat exchange status of the heat pump system. Typically, during heat pump system operation, the saturation temperature corresponding to the refrigerant side exhaust pressure is slightly lower than the outlet water temperature. The closer the two values ​​are, the better the heat exchange efficiency. When the difference is large, this embodiment requires fault detection of the outlet water temperature sensor. Specifically, this embodiment changes the system flow rate by controlling the pump speed set on the inlet side of the heat exchanger, and detects the new inlet and outlet water temperatures of the heat exchanger after the heat pump system stabilizes again. Based on the changes in inlet and outlet water temperatures before and after pump speed adjustment, this embodiment can verify whether the temperature value detected by the outlet water temperature sensor is reasonable and diagnose whether the outlet water temperature sensor has malfunctioned. Therefore, this embodiment performs fault detection of the outlet water temperature sensor before system regulation, thereby avoiding incorrect system regulation caused by inaccurate temperature measurement by the outlet water temperature sensor. Thus, this embodiment improves the stability of the heat pump system operation and helps ensure a better hot water experience for users.

[0021] The above general description and the description below are exemplary and illustrative only and are not intended to limit this application. Attached Figure Description

[0022] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein:

[0023] Figure 1 This is a schematic diagram of the structure of a heat pump system provided in an embodiment of this disclosure;

[0024] Figure 2 This is a schematic diagram of another heat pump system provided in an embodiment of this disclosure;

[0025] Figure 3 This is a schematic diagram of a fault diagnosis method for a heat pump system provided in an embodiment of this disclosure;

[0026] Figure 4 This is a schematic diagram of another fault diagnosis method for a heat pump system provided in an embodiment of this disclosure;

[0027] Figure 5 This is a schematic diagram of another fault diagnosis method for a heat pump system provided in an embodiment of this disclosure;

[0028] Figure 6 This is a schematic diagram of another fault diagnosis method for a heat pump system provided in an embodiment of this disclosure;

[0029] Figure 7 This is a schematic diagram of another fault diagnosis method for a heat pump system provided in an embodiment of this disclosure;

[0030] Figure 8 This is a schematic diagram of another fault diagnosis method for a heat pump system provided in an embodiment of this disclosure;

[0031] Figure 9 This is a schematic diagram of another fault diagnosis method for a heat pump system provided in an embodiment of this disclosure;

[0032] Figure 10 This is a schematic diagram of a fault diagnosis device for a heat pump system provided in an embodiment of this disclosure.

[0033] Figure label:

[0034] 10: Compressor; 20: Four-way valve; 30: Indoor heat exchanger; 40: Throttling device; 50: Outdoor heat exchanger; 61: Inlet water pipe; 62: Outlet water pipe; 70: Heating device; 81: Outlet water temperature sensor; 82: Inlet water temperature sensor; 83: Pressure sensor; 84: Flow sensor; 90: Water pump; 100: Gas-liquid separator. Detailed Implementation

[0035] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0036] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0037] Unless otherwise stated, the term "multiple" means two or more.

[0038] In this embodiment of the disclosure, the character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.

[0039] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0040] The term "correspondence" can refer to an association or binding relationship. The correspondence between A and B means that there is an association or binding relationship between A and B.

[0041] Currently, in heat pump systems used for hot water production, system regulation often relies on the detection of inlet and outlet water temperatures. One related technology discloses a method for controlling a hot water supply device, comprising: determining the exhaust superheat of the compressor; if the exhaust superheat exceeds a first threshold, determining a control scheme for the hot water supply device based on the outlet water temperature of the heat exchanger and the saturation temperature corresponding to the pressure on the refrigerant side of the heat exchanger; and controlling the hot water supply device to execute the control scheme.

[0042] The control methods of related technologies rely on the detection of the outlet water temperature of the heat exchanger, thus requiring high accuracy from the outlet water temperature sensor. However, these technologies lack fault monitoring methods for the temperature sensor. If the outlet water temperature sensor malfunctions and fails to measure the temperature accurately, the control of related systems will be affected, which in turn will affect the stability of the heat pump system and compromise the user's hot water experience.

[0043] It should be noted that conventional methods for diagnosing temperature sensors involve detecting short circuits or open circuits. However, if the outlet water temperature sensor experiences a short circuit or open circuit, it ceases to function properly. This significantly impacts related controls based on the outlet water temperature, leading to large fluctuations in hot water temperature and negatively affecting the user's hot water experience. Therefore, there is an urgent need for a technology that can perform outlet water temperature sensor fault diagnosis earlier in the control process.

[0044] Combination Figure 1 As shown in the figure, this disclosure provides a heat pump system, including a refrigerant circulation loop, a water circulation loop, and a fault diagnosis device for the heat pump system (not shown). The refrigerant circulation loop is formed by connecting a compressor 10, a four-way valve 20, an indoor heat exchanger 30, a throttling device 40, and an outdoor heat exchanger 50 via refrigerant piping. The water circulation loop is formed by connecting an inlet water pipe 61, the indoor heat exchanger 30, and an outlet water pipe 62. A water pump 90 is installed in the inlet water pipe 61, and an outlet water temperature sensor 81 is installed in the outlet water pipe 62. The outlet water temperature sensor 81 is configured to detect the outlet water temperature of the water circulation loop. The rotational speed of the water pump 90 is controllable and adjustable to adjust the water flow rate through the indoor heat exchanger 30.

[0045] The heat pump system provided in this embodiment can adjust the speed of the water pump 90 when there is a significant difference between the outlet water temperature of the indoor heat exchanger 30 and the saturation temperature corresponding to the refrigerant side exhaust pressure. Changes in the speed of the water pump 90 alter the system's water flow rate, thereby changing the inlet and outlet water temperature difference. Therefore, this embodiment can verify the rationality of the outlet water temperature after adjusting the water pump 90 speed using a heat calculation formula, thus completing the fault diagnosis of the outlet water temperature sensor 81. Furthermore, since this fault diagnosis step occurs before system regulation, this embodiment can avoid erroneous system regulation caused by inaccurate temperature measurement by the outlet water temperature sensor 81. This improves the stability of the heat pump system's operation and helps ensure a better hot water experience for users.

[0046] Optionally, combined Figure 2 As shown, the heat pump system also includes: a heating device 70, an inlet water temperature sensor 82, a pressure sensor 83, a flow sensor 84, and a gas-liquid separator 100. The heating device 70 is located in the outlet water pipe 62 and can be controlled to start and stop to adjust the total heat exchange of the heat pump system. The inlet water temperature sensor 82 is located in the inlet water pipe 61 and also in the outlet water pipe of the water pump 90, configured to detect the inlet water temperature of the water circulation loop. The pressure sensor 83 is located in the refrigerant pipe between the exhaust port of the compressor 10 and the four-way valve 20, configured to detect the exhaust pressure of the refrigerant circulation loop. The flow sensor 84 is located in the inlet water pipe 61 and also in the outlet water pipe of the water pump 90, configured to detect the water flow rate of the water circulation loop. The gas-liquid separator 100 is located in the refrigerant pipe between the suction port of the compressor 10 and the four-way valve 20, configured to separate the gaseous and liquid refrigerant returning to the compressor 10.

[0047] Thus, when the outlet water temperature of the indoor heat exchanger 30 differs significantly from the saturation temperature corresponding to the refrigerant side exhaust pressure, this embodiment can also control the heating device 70 to start. The operation of the heating device 70 can change the total heat exchange of the system, thereby causing a change in the inlet and outlet water temperature difference. Therefore, this embodiment can use the heat calculation formula to verify whether the outlet water temperature after the heating device 70 starts is reasonable, thereby completing another fault diagnosis of the outlet water temperature sensor 81. And since this fault diagnosis step occurs before system regulation, this embodiment can avoid incorrect system regulation caused by inaccurate temperature measurement by the outlet water temperature sensor 81. This can improve the stability of the heat pump system operation and help ensure the user's hot water experience.

[0048] Optionally, the indoor heat exchanger 30 is a plate heat exchanger. In this way, embodiments of the present disclosure can achieve heat exchange between two liquids, thereby utilizing the heat dissipation of the refrigerant to heat the water.

[0049] Optionally, the heating device 70 is an electromagnetic heating device. Thus, this embodiment of the present disclosure can utilize the principle of electromagnetic induction heating to increase the total heat exchange of the system, which is beneficial for further increasing the outlet water temperature.

[0050] Optionally, the throttling device 40 is an electronic expansion valve. Thus, embodiments of this disclosure can adjust the flow rate of the refrigerant circulation loop by controlling the opening degree of the electronic expansion valve.

[0051] Optionally, the water circulation loop also includes a water tank (not shown in the figure). The inlet of the water tank is connected to the outlet pipe 62. In this way, the embodiments of this disclosure can utilize the water tank to store hot water for convenient use by the user at any time.

[0052] Optionally, the outlet of the water tank is connected to the inlet pipe 61. In this way, the embodiments of this disclosure can further enhance circulation to make fuller use of the heat dissipation of the refrigerant.

[0053] Combination Figure 3 As shown in the figure, this disclosure provides a fault diagnosis method for a heat pump system, including:

[0054] S301, under the condition of stable operation of the heat pump system, the processor obtains the first outlet water temperature and the first inlet water temperature of the water circulation loop, and obtains the exhaust pressure of the refrigerant circulation loop.

[0055] S302, the processor calculates the difference between the saturation temperature corresponding to the exhaust pressure and the first outlet water temperature to obtain the heat exchange temperature difference.

[0056] S303: When the absolute value of the heat exchange temperature difference is greater than the preset temperature difference threshold, the processor adjusts the water pump speed.

[0057] S304, once the heat pump system is running stably again, the processor obtains the second outlet water temperature and the second inlet water temperature of the water circulation loop.

[0058] S305, the processor diagnoses whether the outlet water temperature sensor is malfunctioning based on the first outlet water temperature, the first inlet water temperature, the second outlet water temperature, and the second inlet water temperature.

[0059] The fault diagnosis method for a heat pump system provided in this disclosure first compares the difference between the outlet water temperature of the heat exchanger and the saturation temperature corresponding to the refrigerant side exhaust pressure when the heat pump system is operating stably, thereby determining the heat exchange status of the heat pump system. Typically, during heat pump system heating operation, the saturation temperature corresponding to the refrigerant side exhaust pressure is slightly lower than the outlet water temperature. The closer the two values ​​are, the better the heat exchange efficiency. When the difference is large, this disclosure requires fault detection of the outlet water temperature sensor. Specifically, this disclosure changes the system flow rate by controlling the pump speed set on the inlet side of the heat exchanger, and detects the new inlet and outlet water temperatures of the heat exchanger after the heat pump system stabilizes again. Based on the changes in inlet and outlet water temperatures before and after pump speed adjustment, this disclosure can verify whether the temperature value detected by the outlet water temperature sensor is reasonable, and diagnose whether the outlet water temperature sensor has malfunctioned. Therefore, this disclosure performs fault detection of the outlet water temperature sensor before system regulation, thereby avoiding erroneous system regulation caused by inaccurate temperature measurement by the outlet water temperature sensor. Therefore, the embodiments disclosed herein can improve the stability of heat pump system operation and help ensure the user's hot water experience.

[0060] Optionally, the preset temperature difference threshold can be set according to the specific operating conditions of the system. Preferably, the preset temperature difference threshold can be set to 4℃. This value can also be adjusted appropriately based on other parameters such as the compressor operating frequency, or it can be set to any other value such as 3℃ or 5℃.

[0061] Optionally, the processor diagnoses whether the outlet water temperature sensor is faulty based on the first outlet water temperature, the first inlet water temperature, the second outlet water temperature, and the second inlet water temperature. This includes: the processor calculating the difference between the second outlet water temperature and the second inlet water temperature to obtain a second supply water temperature difference; and calculating the difference between the first outlet water temperature and the first inlet water temperature to obtain a first supply water temperature difference; the processor calculating the ratio of the second supply water temperature difference to the first supply water temperature difference to obtain a supply water temperature difference ratio detection value; the processor obtaining a theoretical value of the supply water temperature difference ratio; and the processor diagnosing whether the outlet water temperature sensor is faulty based on the supply water temperature difference ratio detection value and the theoretical value of the supply water temperature difference ratio. Thus, this embodiment of the present disclosure can detect the supply water temperature difference before and after the water pump speed adjustment, and use the ratio of the two to represent the actual change in the supply water temperature difference. Simultaneously, this embodiment of the present disclosure can also calculate the theoretical ratio corresponding to this change based on the heat calculation formula. By comparing the detected ratio of the water supply temperature difference before and after the water pump speed adjustment with the theoretical ratio, the embodiments of this disclosure can verify whether the temperature value detected by the outlet water temperature sensor is reasonable, and diagnose whether the outlet water temperature sensor has malfunctioned.

[0062] Optionally, the processor diagnoses whether the outlet water temperature sensor is faulty based on the detected value and the theoretical value of the supply water temperature difference ratio. This includes: the processor calculating the difference between the detected value and the theoretical value of the supply water temperature difference ratio, and calculating the ratio of the absolute value of this difference to the theoretical value of the supply water temperature difference ratio to obtain the deviation range of the supply water temperature difference ratio; the processor diagnoses whether the outlet water temperature sensor is faulty based on the deviation range of the supply water temperature difference ratio. Thus, this embodiment compares the detected ratio and the theoretical ratio of the supply water temperature difference before and after the water pump speed adjustment, and further calculates the deviation range between the two. Based on the magnitude of the deviation range, this embodiment can verify whether the temperature value detected by the outlet water temperature sensor is reasonable, and diagnose whether the outlet water temperature sensor is faulty.

[0063] Optionally, the processor diagnoses whether the outlet water temperature sensor is faulty based on the deviation of the supply water temperature difference ratio. This includes: if the deviation of the supply water temperature difference ratio is greater than or equal to a first preset deviation range, the processor diagnoses the outlet water temperature sensor as faulty; if the deviation of the supply water temperature difference ratio is less than the first preset deviation range, the processor diagnoses the outlet water temperature sensor as not faulty. Thus, this embodiment compares the detected ratio and the theoretical ratio of the supply water temperature difference before and after pump speed adjustment, and further calculates the deviation range between the two. When the deviation range exceeds a certain preset value, it indicates a large discrepancy between the detected ratio and the theoretical ratio of the corresponding supply water temperature difference change. Therefore, this embodiment determines that the temperature value detected by the outlet water temperature sensor is unreasonable, and thus diagnoses the outlet water temperature sensor as faulty. Conversely, it diagnoses the outlet water temperature sensor as not faulty. Therefore, this embodiment can complete fault diagnosis without disassembling the temperature sensor. Furthermore, it is no longer limited to detecting short circuits or open circuits, but can proactively react by analyzing the deviation of temperature data. This avoids erroneous system control caused by inaccurate temperature measurement by the outlet water temperature sensor. Therefore, the embodiments disclosed herein can improve the stability of heat pump system operation and help ensure the user's hot water experience.

[0064] Optionally, the processor determines that the heat pump system is operating stably by: acquiring the compressor's exhaust superheat; and determining that the heat pump system is operating stably when the exhaust superheat is greater than or equal to a preset superheat. Thus, this embodiment of the present disclosure can ensure stable operation of the refrigerant side of the system, thereby guaranteeing that the refrigerant can release sufficient heat to heat the water temperature.

[0065] Optionally, the processor determines that the heat pump system is operating stably by: acquiring the outlet water temperature change rate; and determining that the heat pump system is operating stably when the outlet water temperature change rate is less than or equal to a preset change rate. In this way, the embodiments of this disclosure can perform the next adjustment action only when the outlet water temperature tends to stabilize, thereby avoiding erroneous adjustments based on inaccurate outlet water temperatures during the water temperature rise process.

[0066] Optionally, the processor determines that the heat pump system is operating stably by: acquiring the cumulative operating time after each adjustment action; and determining that the heat pump system is operating stably if the cumulative operating time is greater than or equal to a preset time. Thus, this embodiment of the present disclosure can wait a preset time after each adjustment action before executing the next adjustment action, thereby ensuring that all system parameters tend to stabilize and improving the reliability of system regulation.

[0067] Optionally, the fault diagnosis method for the heat pump system further includes: the processor diagnosing whether the inlet water temperature sensor is faulty based on the first inlet water temperature and the second inlet water temperature. Thus, by analyzing the changes in inlet water temperature before and after pump speed adjustment, this embodiment can verify whether the temperature value detected by the inlet water temperature sensor is reasonable, and diagnose whether the inlet water temperature sensor is faulty. Therefore, this embodiment completes fault detection of the inlet water temperature sensor before detecting faults in the outlet water temperature sensor, thereby avoiding subsequent incorrect judgments due to inaccurate temperature measurement by the inlet water temperature sensor.

[0068] Optionally, the processor diagnoses whether the inlet water temperature sensor is faulty based on the first and second inlet water temperatures. This includes: the processor calculating the difference between the second and first inlet water temperatures to obtain the inlet water temperature difference; if the absolute value of the inlet water temperature difference is greater than or equal to an inlet water temperature difference threshold, the processor diagnoses that the inlet water temperature sensor is faulty; if the absolute value of the inlet water temperature difference is less than the inlet water temperature difference threshold, the processor diagnoses that the inlet water temperature sensor is not faulty. Thus, based on the difference in inlet water temperature before and after pump speed adjustment, this embodiment can verify whether the temperature value detected by the inlet water temperature sensor is within a reasonable fluctuation range, and diagnose whether the inlet water temperature sensor is faulty accordingly. Therefore, this embodiment completes fault detection of the inlet water temperature sensor before performing fault detection on the outlet water temperature sensor, thereby avoiding subsequent incorrect judgments due to inaccurate temperature measurement by the inlet water temperature sensor.

[0069] Combination Figure 4 As shown, this disclosure provides another method for fault diagnosis of a heat pump system, including:

[0070] S401, under the condition of stable operation of the heat pump system, the processor obtains the first outlet water temperature and the first inlet water temperature of the water circulation loop, and obtains the exhaust pressure of the refrigerant circulation loop.

[0071] S402, the processor calculates the difference between the saturation temperature corresponding to the exhaust pressure and the first outlet water temperature to obtain the heat exchange temperature difference.

[0072] S403: When the absolute value of the heat exchange temperature difference is greater than the preset temperature difference threshold, the processor adjusts the water pump speed.

[0073] S404, once the heat pump system is running stably again, the processor obtains the second outlet water temperature and the second inlet water temperature of the water circulation loop.

[0074] S405, the processor calculates the difference between the second outlet water temperature and the second inlet water temperature to obtain the second water supply temperature difference, and calculates the difference between the first outlet water temperature and the first inlet water temperature to obtain the first water supply temperature difference.

[0075] S406, the processor calculates the ratio of the second water supply temperature difference to the first water supply temperature difference, and obtains the water supply temperature difference ratio detection value.

[0076] S407, the processor obtains the theoretical value of the water supply temperature difference ratio.

[0077] S408, the processor calculates the difference between the detected value of the water supply temperature difference ratio and the theoretical value of the water supply temperature difference ratio, and calculates the ratio of the absolute value of the difference to the theoretical value of the water supply temperature difference ratio to obtain the deviation range of the water supply temperature difference ratio.

[0078] S409, if the deviation of the water supply temperature difference ratio is greater than or equal to the first preset deviation range, the processor diagnoses a malfunction in the water temperature sensor.

[0079] S410, if the deviation of the water supply temperature difference ratio is less than the first preset deviation range, the processor diagnoses that the water temperature sensor is not faulty.

[0080] The fault diagnosis method for a heat pump system provided in this disclosure first compares the difference between the outlet water temperature of the heat exchanger and the saturation temperature corresponding to the refrigerant side exhaust pressure when the heat pump system is operating stably, and then determines the heat exchange status of the heat pump system based on this difference. Normally, when the heat pump system is operating in heating mode, the saturation temperature corresponding to the refrigerant side exhaust pressure is slightly lower than the outlet water temperature. The closer the two values ​​are, the better the heat exchange efficiency. When the difference is large, this disclosure requires fault detection of the outlet water temperature sensor. Specifically, this disclosure changes the system flow rate by controlling the pump speed set on the inlet side of the heat exchanger, and detects the new inlet and outlet water temperatures of the heat exchanger after the heat pump system stabilizes again. Based on the inlet and outlet water temperatures detected before and after the pump speed adjustment, this disclosure can obtain the detected ratio and theoretical ratio of the supply water temperature difference, and further calculate the deviation amplitude between the two. When the deviation amplitude exceeds a certain preset value, it indicates that the detected ratio and theoretical ratio of the corresponding supply water temperature difference change are significantly different. Therefore, this disclosure determines that the temperature value detected by the outlet water temperature sensor is unreasonable, and thus diagnoses a fault in the outlet water temperature sensor. Conversely, if the temperature sensor does not malfunction, the system is diagnosed as not being faulty. Therefore, this embodiment of the invention can perform fault diagnosis without disassembling the temperature sensor. Furthermore, it is no longer limited to detecting short circuits or open circuits, but can proactively react by analyzing deviations in temperature data. This avoids erroneous system control caused by inaccurate temperature readings from the outlet water temperature sensor. Therefore, this embodiment of the invention improves the stability of the heat pump system, thus enhancing the user's hot water experience.

[0081] Optionally, the first preset deviation amplitude can be set according to the sensor's own configuration. Preferably, the first preset deviation amplitude can be set to 30%. This value can also be adjusted according to the specific operating conditions of the system, or it can be set to any other arbitrary value such as 50% or 100%.

[0082] Optionally, the processor acquires the theoretical value of the water supply temperature difference ratio, including: the processor controlling the flow sensor to acquire the first water supply flow rate before the water pump speed is adjusted; the processor controlling the flow sensor to acquire the second water supply flow rate after the water pump speed is adjusted; and the processor calculating the theoretical value of the water supply temperature difference ratio according to the heat calculation formula based on the first and second water supply flow rates. Thus, this embodiment of the present disclosure can control the system water flow rate by adjusting the water pump speed. Combined with the heat calculation formula Q=C*m*ΔT, under the condition that other parameters remain unchanged, the total mass m of the water participating in heat exchange will also change due to the change in water flow rate q per unit time. Moreover, this change value is easily obtained; therefore, this embodiment of the present disclosure can easily calculate the change value of the water supply temperature difference ΔT, i.e., the theoretical value of the water supply temperature difference ratio.

[0083] Specifically, the calculation process for the theoretical value of the supply water temperature difference ratio is further explained. First, the heat calculation formula Q=C*m*ΔT is analyzed. Where Q is the total heat exchange of the system. C is the specific heat capacity of water. m is the total mass of water participating in heat exchange, and m=ρ*q*t, where ρ is the density of water, q is the water flow rate in the water circulation loop, and t is the total duration of heat exchange. ΔT is the supply water temperature difference, and ΔT=T wo -T wi T wo T represents the outlet water temperature. wi This refers to the inlet water temperature.

[0084] Before adjusting the water pump speed, the total heat exchange of the system is Q1 = C * ρ * q1 * t * (T) wo1 -T wi1 Where t is the duration of water flow through the indoor heat exchanger in the water circulation loop, q1 is the initial water supply flow rate before the pump speed is adjusted, and T wo1 The first outlet water temperature, T wi1 This is the first inlet water temperature.

[0085] After adjusting the pump speed, the total heat exchange of the system is Q2 = C * ρ * q2 * t * (T) wo2 -T wi2 Where q2 is the second water supply flow rate after the pump speed is adjusted, and T wo2 The second outlet water temperature, T wi2 This is the second inlet water temperature.

[0086] Since the total heat exchange of the system before and after the water pump speed adjustment both come from the heat released during the refrigerant heat exchange in the indoor heat exchanger, Q1 = Q2.

[0087] By combining the above equations, the change in the supply water temperature difference ΔT before and after the pump speed adjustment can be obtained, that is, the theoretical value of the supply water temperature difference ratio ΔT2 / ΔT1 = (T wo2 -T wi1 ) / (T wo1 -T wi1 = q1 / q2. Therefore, by determining the water flow rate corresponding to the pump speed before and after adjustment, and combining this embodiment with the heat calculation formula, the theoretical value of the water supply temperature difference ratio can be easily calculated. This allows verification of the reasonableness of the temperature value detected by the outlet water temperature sensor, and is helpful in diagnosing whether the outlet water temperature sensor has malfunctioned.

[0088] Combination Figure 5 As shown, this disclosure provides another method for fault diagnosis of a heat pump system, including:

[0089] S501, under the condition of stable operation of the heat pump system, the processor obtains the first outlet water temperature and the first inlet water temperature of the water circulation loop, and obtains the exhaust pressure of the refrigerant circulation loop.

[0090] S502, the processor calculates the difference between the saturation temperature corresponding to the exhaust pressure and the first outlet water temperature to obtain the heat exchange temperature difference.

[0091] S403: When the absolute value of the heat exchange temperature difference is greater than the preset temperature difference threshold, the processor adjusts the water pump speed.

[0092] S504, once the heat pump system is running stably again, the processor obtains the second outlet water temperature and the second inlet water temperature of the water circulation loop.

[0093] S505, the processor calculates the difference between the second outlet water temperature and the second inlet water temperature to obtain the second supply water temperature difference, and calculates the difference between the first outlet water temperature and the first inlet water temperature to obtain the first supply water temperature difference.

[0094] S506, the processor calculates the ratio of the second water supply temperature difference to the first water supply temperature difference, and obtains the water supply temperature difference ratio detection value.

[0095] S507, the processor obtains the theoretical value of the water supply temperature difference ratio.

[0096] S508, the processor calculates the difference between the detected value of the water supply temperature difference ratio and the theoretical value of the water supply temperature difference ratio, and calculates the ratio of the absolute value of the difference to the theoretical value of the water supply temperature difference ratio to obtain the deviation range of the water supply temperature difference ratio.

[0097] S509, if the deviation of the water supply temperature difference ratio is greater than or equal to the first preset deviation range, the processor diagnoses a malfunction in the water temperature sensor.

[0098] S510: If the deviation of the water supply temperature difference ratio is less than the first preset deviation range, the processor diagnoses that the water temperature sensor is not faulty.

[0099] S511, when the deviation of the water supply temperature difference ratio is greater than or equal to the second preset deviation range, the processor corrects the water outlet temperature detected by the water outlet temperature sensor and outputs the corrected water outlet temperature.

[0100] The second preset deviation amplitude is smaller than the first preset deviation amplitude.

[0101] S512, when the deviation of the water supply temperature difference ratio is less than the second preset deviation range, the processor outputs the water outlet temperature detected by the water outlet temperature sensor.

[0102] The fault diagnosis method for a heat pump system provided in this disclosure first compares the difference between the outlet water temperature of the heat exchanger and the saturation temperature corresponding to the refrigerant side exhaust pressure when the heat pump system is operating stably, and then determines the heat exchange status of the heat pump system based on this difference. Normally, when the heat pump system is operating in heating mode, the saturation temperature corresponding to the refrigerant side exhaust pressure is slightly lower than the outlet water temperature. The closer the two values ​​are, the better the heat exchange efficiency. When the difference is large, this disclosure requires fault detection of the outlet water temperature sensor. Specifically, this disclosure changes the system flow rate by controlling the pump speed set on the inlet side of the heat exchanger, and detects the new inlet and outlet water temperatures of the heat exchanger after the heat pump system stabilizes again. Based on the inlet and outlet water temperatures detected before and after the pump speed adjustment, this disclosure can obtain the detected ratio and theoretical ratio of the supply water temperature difference, and further calculate the deviation amplitude between the two. When the deviation amplitude exceeds a certain preset value, it indicates that the detected ratio and theoretical ratio of the corresponding supply water temperature difference change are significantly different. Therefore, this disclosure determines that the temperature value detected by the outlet water temperature sensor is unreasonable, and thus diagnoses a fault in the outlet water temperature sensor. Conversely, if the temperature readings are within the range of deviation, the system diagnoses that the outlet water temperature sensor is not faulty, and further determines the output mode of the outlet water temperature based on the deviation range. This improves the accuracy of the temperature values ​​detected by the outlet water temperature sensor, enhancing the reliability of system control. Therefore, this embodiment of the disclosure can complete fault diagnosis without disassembling the temperature sensor. Furthermore, it is no longer limited to detecting short circuits or open circuits, but can proactively react by analyzing temperature data deviations. This avoids erroneous system control caused by inaccurate temperature readings from the outlet water temperature sensor. Therefore, this embodiment of the disclosure improves the stability of the heat pump system, ensuring a better hot water experience for users.

[0103] Optionally, the second preset deviation amplitude can be set according to the sensor's own configuration. However, it should be noted that the second preset deviation amplitude should be less than the first preset deviation amplitude. Preferably, the second preset deviation amplitude can be set to 10%. This value can also be adjusted according to the specific operating conditions of the system, and can be set to any other arbitrary value such as 15% or 30%.

[0104] Optionally, the processor corrects the outlet water temperature detected by the outlet water temperature sensor and outputs the corrected outlet water temperature. This includes: the processor calculating the difference between the theoretical outlet water temperature and the detected outlet water temperature to obtain a theoretical outlet water temperature difference; the processor determining a correction coefficient based on the theoretical outlet water temperature difference; the processor multiplying the correction coefficient by the theoretical outlet water temperature difference to obtain a corrected outlet water temperature value; and the processor adding the detected outlet water temperature value to the corrected outlet water temperature value to obtain the corrected outlet water temperature and outputting it. Thus, this embodiment of the present disclosure does not directly output the theoretical outlet water temperature value, but instead selects a compromise value for output. This avoids excessive correction affecting the stability of the heat pump system and also ensures the user's hot water experience.

[0105] Combination Figure 6 As shown, this disclosure provides another method for fault diagnosis of a heat pump system, including:

[0106] S601, under the condition of stable operation of the heat pump system, the processor obtains the first outlet water temperature and the first inlet water temperature of the water circulation loop, and obtains the exhaust pressure of the refrigerant circulation loop.

[0107] S602, the processor calculates the difference between the saturation temperature corresponding to the exhaust pressure and the first outlet water temperature to obtain the heat exchange temperature difference.

[0108] S603: When the absolute value of the heat exchange temperature difference is greater than the preset temperature difference threshold, the processor adjusts the water pump speed.

[0109] S604, once the heat pump system is running stably again, the processor obtains the second outlet water temperature and the second inlet water temperature of the water circulation loop.

[0110] The S605 processor diagnoses whether the outlet water temperature sensor is malfunctioning based on the first outlet water temperature, the first inlet water temperature, the second outlet water temperature, and the second inlet water temperature.

[0111] S606, if the water temperature sensor is found to be functioning correctly, the processor will adjust the water pump speed accordingly.

[0112] S607: Once the heat pump system is running stably again, the processor adjusts the operating parameters of the heat pump system based on the heat exchange temperature difference.

[0113] The fault diagnosis method for a heat pump system provided in this disclosure first compares the difference between the outlet water temperature of the heat exchanger and the saturation temperature corresponding to the refrigerant side exhaust pressure when the heat pump system is operating stably, thereby determining the heat exchange status of the heat pump system. Typically, during heat pump system heating operation, the saturation temperature corresponding to the refrigerant side exhaust pressure is slightly lower than the outlet water temperature. The closer the two values ​​are, the better the heat exchange efficiency. When the difference is large, this disclosure requires fault detection of the outlet water temperature sensor. Specifically, this disclosure changes the system flow rate by controlling the pump speed set on the inlet side of the heat exchanger, and detects the new inlet and outlet water temperatures of the heat exchanger after the heat pump system stabilizes again. Based on the changes in inlet and outlet water temperatures before and after pump speed adjustment, this disclosure can verify whether the temperature value detected by the outlet water temperature sensor is reasonable, and diagnose whether the outlet water temperature sensor has malfunctioned. Therefore, this disclosure performs fault detection of the outlet water temperature sensor before system regulation, thereby avoiding erroneous system regulation caused by inaccurate temperature measurement by the outlet water temperature sensor. Furthermore, after detecting that no fault has occurred, this embodiment restores the system to its original operating conditions and adjusts the heat pump system's functions in conjunction with the heat exchange temperature difference to improve the system's heat exchange efficiency. Therefore, this embodiment can improve the stability of the heat pump system's operation, which is beneficial to ensuring the user's hot water experience.

[0114] Optionally, the processor adjusts the operating parameters of the heat pump system based on the heat exchange temperature difference, including adjusting the compressor's operating frequency and / or the opening degree of the throttling device based on the heat exchange temperature difference. Thus, embodiments of this disclosure can rationally regulate the refrigerant side of the system in conjunction with the heat exchange temperature difference to minimize the heat exchange temperature difference and improve heat exchange efficiency.

[0115] Combination Figure 7 As shown, this disclosure provides another method for fault diagnosis of a heat pump system, including:

[0116] S701, under the condition of stable operation of the heat pump system, the processor obtains the first outlet water temperature and the first inlet water temperature of the water circulation loop, and obtains the exhaust pressure of the refrigerant circulation loop.

[0117] S702, the processor calculates the difference between the saturation temperature corresponding to the exhaust pressure and the first outlet water temperature to obtain the heat exchange temperature difference.

[0118] S703: When the absolute value of the heat exchange temperature difference is greater than the preset temperature difference threshold, the processor adjusts the water pump speed.

[0119] S704, once the heat pump system is running stably again, the processor obtains the second outlet water temperature and the second inlet water temperature of the water circulation loop.

[0120] The S705 processor diagnoses whether the outlet water temperature sensor is malfunctioning based on the first outlet water temperature, the first inlet water temperature, the second outlet water temperature, and the second inlet water temperature.

[0121] S706, if the water temperature sensor is found to be functioning correctly, the processor will adjust the water pump speed accordingly.

[0122] S707: Once the heat pump system is running stably again, the processor adjusts the operating parameters of the heat pump system based on the heat exchange temperature difference.

[0123] In the event of a fault detected by the S708 heat pump system, the processor controls the heat pump system to issue a fault alarm.

[0124] The fault diagnosis method for a heat pump system provided in this disclosure first compares the difference between the outlet water temperature of the heat exchanger and the saturation temperature corresponding to the refrigerant side exhaust pressure when the heat pump system is operating stably, thereby determining the heat exchange status of the heat pump system. Typically, during heat pump system heating operation, the saturation temperature corresponding to the refrigerant side exhaust pressure is slightly lower than the outlet water temperature. The closer the two values ​​are, the better the heat exchange efficiency. When the difference is large, this disclosure requires fault detection of the outlet water temperature sensor. Specifically, this disclosure changes the system flow rate by controlling the pump speed set on the inlet side of the heat exchanger, and detects the new inlet and outlet water temperatures of the heat exchanger after the heat pump system stabilizes again. Based on the changes in inlet and outlet water temperatures before and after pump speed adjustment, this disclosure can verify whether the temperature value detected by the outlet water temperature sensor is reasonable, and diagnose whether the outlet water temperature sensor has malfunctioned. Therefore, this disclosure performs fault detection of the outlet water temperature sensor before system regulation, thereby avoiding erroneous system regulation caused by inaccurate temperature measurement by the outlet water temperature sensor. Furthermore, upon detecting a fault, this embodiment of the present disclosure immediately initiates an alarm to remind the user to replace the outlet water temperature sensor in a timely manner. After detecting that no fault has occurred, this embodiment restores the system to its original operating conditions and, in conjunction with the heat exchange temperature difference, adjusts the heat pump system's functions to improve the system's heat exchange efficiency. Therefore, this embodiment of the present disclosure can improve the stability of the heat pump system's operation, thus helping to ensure the user's hot water usage experience.

[0125] Combination Figure 8 As shown, this disclosure provides another method for fault diagnosis of a heat pump system, including:

[0126] S801, under the condition of stable operation of the heat pump system, the processor obtains the first outlet water temperature and the first inlet water temperature of the water circulation loop, and obtains the exhaust pressure of the refrigerant circulation loop.

[0127] S802, the processor calculates the difference between the saturation temperature corresponding to the exhaust pressure and the first outlet water temperature to obtain the heat exchange temperature difference.

[0128] S803: When the absolute value of the heat exchange temperature difference is greater than the preset temperature difference threshold, the processor controls the heating device to start.

[0129] S804, once the heat pump system is running stably again, the processor obtains the third outlet water temperature and the third inlet water temperature of the water circulation loop.

[0130] The S805 processor diagnoses whether the outlet water temperature sensor is malfunctioning based on the first outlet water temperature, the first inlet water temperature, the third outlet water temperature, and the third inlet water temperature.

[0131] The fault diagnosis method for a heat pump system provided in this disclosure first compares the difference between the outlet water temperature of the heat exchanger and the saturation temperature corresponding to the refrigerant side exhaust pressure when the heat pump system is operating stably, thereby determining the heat exchange status of the heat pump system. Typically, when the heat pump system is operating in heating mode, the saturation temperature corresponding to the refrigerant side exhaust pressure is slightly lower than the outlet water temperature. The closer the two values ​​are, the better the heat exchange efficiency. When the difference is large, this disclosure requires fault detection of the outlet water temperature sensor. Specifically, this disclosure changes the total heat exchange capacity of the system by controlling the heating device installed on the outlet water side of the heat exchanger, and detects the new inlet and outlet water temperatures of the heat exchanger after the heat pump system stabilizes again. Based on the changes in inlet and outlet water temperatures before and after the heating device adjustment, this disclosure can verify whether the temperature value detected by the outlet water temperature sensor is reasonable, and diagnose whether the outlet water temperature sensor has malfunctioned. Therefore, this disclosure performs fault detection of the outlet water temperature sensor before system regulation, thereby avoiding erroneous system regulation caused by inaccurate temperature measurement by the outlet water temperature sensor. Therefore, the embodiments disclosed herein can improve the stability of heat pump system operation and help ensure the user's hot water experience.

[0132] Optionally, the processor diagnoses whether the outlet water temperature sensor is faulty based on the first outlet water temperature, the first inlet water temperature, the second outlet water temperature, and the second inlet water temperature. This includes: the processor calculating the difference between the second outlet water temperature and the second inlet water temperature to obtain a second supply water temperature difference; and calculating the difference between the first outlet water temperature and the first inlet water temperature to obtain a first supply water temperature difference; the processor calculating the difference between the second supply water temperature difference and the first supply water temperature difference to obtain a supply water temperature difference detection value; the processor obtaining a theoretical value of the supply water temperature difference; and the processor diagnosing whether the outlet water temperature sensor is faulty based on the supply water temperature difference detection value and the theoretical value of the supply water temperature difference. Thus, this embodiment of the present disclosure can detect the supply water temperature difference before and after the heating device is started, and use the difference between the two to represent the actual change in the supply water temperature difference. Simultaneously, this embodiment of the present disclosure can also calculate the theoretical difference corresponding to this change based on the heat calculation formula. By comparing the detected difference and the theoretical difference in water supply temperature before and after the heating device is started, the embodiments of this disclosure can verify whether the temperature value detected by the outlet water temperature sensor is reasonable, and diagnose whether the outlet water temperature sensor has malfunctioned.

[0133] Optionally, the processor obtains the theoretical value of the supply water temperature difference, including: the processor obtaining the heating power of the heating device; and the processor calculating the theoretical value of the supply water temperature difference according to the heat calculation formula based on the heating power. Thus, this embodiment of the present disclosure can obtain the change in the total heat exchange of the system based on the heating power. Combined with the heat calculation formula Q=C*m*ΔT, with other parameters remaining unchanged, this embodiment of the present disclosure can easily calculate the change in the supply water temperature difference ΔT, i.e., the theoretical value of the supply water temperature difference, from the change in the total heat exchange Q.

[0134] Optionally, the processor diagnoses whether the outlet water temperature sensor is faulty based on the detected value and the theoretical value of the supply water temperature difference. This includes: the processor calculating the difference between the detected value and the theoretical value of the supply water temperature difference, and calculating the ratio of the absolute value of the difference to the theoretical value to obtain the deviation range of the supply water temperature difference; the processor diagnoses whether the outlet water temperature sensor is faulty based on the deviation range of the supply water temperature difference. Thus, this embodiment compares the detected difference and the theoretical difference of the supply water temperature difference before and after the heating device is started, and further calculates the deviation range between the two. Based on the magnitude of the deviation range, this embodiment can verify whether the temperature value detected by the outlet water temperature sensor is reasonable, and diagnose whether the outlet water temperature sensor is faulty.

[0135] Optionally, the processor diagnoses whether the outlet water temperature sensor is faulty based on the deviation range of the supply water temperature difference, including: if the deviation range is greater than or equal to a first preset deviation range, the processor diagnoses the outlet water temperature sensor as faulty; if the deviation range is less than the first preset deviation range, the processor diagnoses the outlet water temperature sensor as not faulty. Thus, this embodiment compares the detected difference and the theoretical difference of the supply water temperature difference before and after the heating device is started, and further calculates the deviation range. When the deviation range exceeds a certain preset value, it indicates that the detected difference and the theoretical difference of the corresponding change in supply water temperature difference are significantly different. Therefore, this embodiment determines that the temperature value detected by the outlet water temperature sensor is unreasonable, and thus diagnoses the outlet water temperature sensor as faulty. Conversely, it diagnoses the outlet water temperature sensor as not faulty. Therefore, this embodiment can complete fault diagnosis without disassembling the temperature sensor. Furthermore, it is no longer limited to detecting short circuits or open circuits, but can proactively react by analyzing the deviation of temperature data. This avoids erroneous system control caused by inaccurate temperature measurement by the outlet water temperature sensor. Therefore, the embodiments disclosed herein can improve the stability of heat pump system operation and help ensure the user's hot water experience.

[0136] Combination Figure 9 As shown, this disclosure provides another method for fault diagnosis of a heat pump system, including:

[0137] S901, under the condition of stable operation of the heat pump system, the processor obtains the first outlet water temperature and the first inlet water temperature of the water circulation loop, and obtains the exhaust pressure of the refrigerant circulation loop.

[0138] S902, the processor calculates the difference between the saturation temperature corresponding to the exhaust pressure and the first outlet water temperature to obtain the heat exchange temperature difference.

[0139] S903: When the absolute value of the heat exchange temperature difference is greater than the preset temperature difference threshold, the processor adjusts the water pump speed.

[0140] S904, once the heat pump system is running stably again, the processor obtains the second outlet water temperature and the second inlet water temperature of the water circulation loop.

[0141] S905, the processor diagnoses whether the outlet water temperature sensor is faulty based on the first outlet water temperature, the first inlet water temperature, the second outlet water temperature, and the second inlet water temperature, and records the first diagnostic result.

[0142] S906, processor adjusts water pump speed.

[0143] S907: Once the heat pump system is running stably again, the processor controls the heating device to start.

[0144] S908, once the heat pump system is running stably again, the processor obtains the third outlet water temperature and the third inlet water temperature of the water circulation loop.

[0145] S909, the processor diagnoses whether the outlet water temperature sensor is faulty based on the first outlet water temperature, the first inlet water temperature, the third outlet water temperature, and the third inlet water temperature, and records the second diagnostic result.

[0146] S910, the processor determines the final diagnostic result of the outlet water temperature sensor based on the first diagnostic result and the second diagnostic result.

[0147] The fault diagnosis method for a heat pump system provided in this disclosure first compares the difference between the outlet water temperature of the heat exchanger and the saturation temperature corresponding to the refrigerant side exhaust pressure when the heat pump system is operating stably, and then determines the heat exchange status of the heat pump system based on this difference. Typically, when the heat pump system is operating in heating mode, the saturation temperature corresponding to the refrigerant side exhaust pressure is slightly lower than the outlet water temperature. The closer the two values ​​are, the better the heat exchange efficiency. When the difference is large, this disclosure requires fault detection of the outlet water temperature sensor. Specifically, this disclosure provides two methods for fault detection: one is to control the pump speed on the inlet side of the heat exchanger to change the system flow rate; the other is to control the heating device on the outlet side of the heat exchanger to change the total heat exchange of the system. After the heat pump system stabilizes again, the corresponding new inlet and outlet water temperatures are detected. Based on the changes in inlet and outlet water temperatures before and after adjusting these two methods, this disclosure can verify the rationality of the temperature value detected by the outlet water temperature sensor from multiple perspectives, thereby more accurately diagnosing whether the outlet water temperature sensor has malfunctioned. Therefore, this embodiment of the present disclosure performs fault detection on the outlet water temperature sensor before system regulation, thereby avoiding erroneous system regulation caused by inaccurate temperature measurement by the outlet water temperature sensor. Thus, this embodiment of the present disclosure improves the stability of the heat pump system operation, which is beneficial to ensuring the user's hot water experience.

[0148] It should be noted that the embodiments disclosed herein do not specifically limit the execution order between the two methods. Specifically, in some embodiments, the total heat exchange of the system can be changed first by controlling the heating device installed on the outlet side of the heat exchanger to obtain a first diagnostic result. Then, the system flow rate can be changed by controlling the speed of the water pump installed on the inlet side of the heat exchanger to obtain a second diagnostic result.

[0149] Combination Figure 10As shown, this disclosure provides a fault diagnosis device for a heat pump system, including a processor 1001 and a memory 1002. Optionally, the device may further include a communication interface 1003 and a bus 1004. The processor 1001, communication interface 1003, and memory 1002 can communicate with each other via the bus 1004. The communication interface 1003 can be used for information transmission. The processor 1001 can call logical instructions in the memory 1002 to execute the fault diagnosis method for the heat pump system described in the above embodiment.

[0150] Furthermore, the logic instructions in the aforementioned memory 1002 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium.

[0151] The memory 1002, as a computer-readable storage medium, can be used to store software programs and computer-executable programs, such as program instructions / modules corresponding to the methods in the embodiments of this disclosure. The processor 1001 executes functional applications and data processing by running the program instructions / modules stored in the memory 1002, thereby implementing the fault diagnosis method of the heat pump system in the above embodiments.

[0152] The memory 1002 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the terminal device. Furthermore, the memory 1002 may include high-speed random access memory and may also include non-volatile memory.

[0153] This disclosure provides a storage medium storing computer-executable instructions, which, when executed, perform the aforementioned fault diagnosis method for a heat pump system.

[0154] The aforementioned storage medium can be a transient computer-readable storage medium or a non-transitory computer-readable storage medium.

[0155] The technical solutions of this disclosure can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes one or more instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in this disclosure. The aforementioned storage medium can be a non-transitory storage medium, including: a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, and other media capable of storing program code; it can also be a transient storage medium.

[0156] The foregoing description and accompanying drawings fully illustrate embodiments of this disclosure to enable those skilled in the art to practice them. Other embodiments may include structural, logical, electrical, procedural, and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the order of operation may vary. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. Moreover, the terminology used in this application is for describing embodiments only and is not intended to limit the claims. As used in the description of embodiments and claims, the singular forms “a,” “an,” and “the” are intended to equally include the plural forms unless the context clearly indicates otherwise. Similarly, the term “and / or” as used in this application means including one or more of the associated listed items and all possible combinations thereof. Additionally, when used in this application, the term "comprise" and its variations "comprises" and / or "comprising" refer to the presence of stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof. Without further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the process, method, or apparatus that includes said element. In this document, each embodiment may focus on the differences from other embodiments, and similar or identical parts between embodiments can be referred to mutually. For methods, products, etc., disclosed in the embodiments, if they correspond to the method section disclosed in the embodiments, the relevant parts can be referred to the description of the method section.

[0157] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of this disclosure. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0158] The methods and products (including but not limited to devices and equipment) disclosed in the embodiments herein can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of units may be merely a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the shown or discussed units may be through some interfaces, and the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units may be selected to implement this embodiment according to actual needs. Furthermore, the functional units in the embodiments of this disclosure may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0159] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than that shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different blocks may also occur in a different order than disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. Each block in a block diagram and / or flowchart, and combinations of blocks in a block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

Claims

1. A fault diagnosis method for a heat pump system, characterized in that, The heat pump system includes a refrigerant circulation loop and a water circulation loop. A water pump is installed in the inlet pipe of the water circulation loop, and an outlet water temperature sensor is installed in the outlet pipe of the water circulation loop. The method includes: Under the condition that the heat pump system is operating stably, the first outlet water temperature and the first inlet water temperature of the water circulation loop are obtained, and the exhaust pressure of the refrigerant circulation loop is obtained. Calculate the difference between the saturation temperature corresponding to the exhaust pressure and the first outlet water temperature to obtain the heat exchange temperature difference; If the absolute value of the heat exchange temperature difference is greater than the preset temperature difference threshold, adjust the speed of the water pump; Once the heat pump system is running stably again, obtain the second outlet water temperature and the second inlet water temperature of the water circulation loop. Based on the first outlet water temperature, the first inlet water temperature, the second outlet water temperature, and the second inlet water temperature, diagnose whether the outlet water temperature sensor is malfunctioning. The step of diagnosing whether the outlet water temperature sensor is malfunctioning based on the first outlet water temperature, the first inlet water temperature, the second outlet water temperature, and the second inlet water temperature includes: Calculate the difference between the second outlet water temperature and the second inlet water temperature to obtain the second supply water temperature difference; and calculate the difference between the first outlet water temperature and the first inlet water temperature to obtain the first supply water temperature difference. Calculate the ratio of the second water supply temperature difference to the first water supply temperature difference to obtain the measured value of the water supply temperature difference ratio; Obtain the theoretical value of the water supply temperature difference ratio; Based on the detected value of the water supply temperature difference ratio and the theoretical value of the water supply temperature difference ratio, diagnose whether the outlet water temperature sensor is malfunctioning.

2. The method according to claim 1, characterized in that, The water circulation loop also includes a flow sensor, which is installed in the inlet pipe and the outlet pipe of the water pump; obtaining the theoretical value of the supply water temperature difference ratio includes: The flow sensor is controlled to obtain the first water supply flow rate before the water pump speed is adjusted. The flow sensor is controlled to obtain the second water supply flow rate after the water pump speed is adjusted. Based on the first and second water supply flow rates, the theoretical value of the water supply temperature difference ratio is calculated according to the heat calculation formula.

3. The method according to claim 2, characterized in that, The step of diagnosing whether the outlet water temperature sensor is malfunctioning based on the detected value of the supply water temperature difference ratio and the theoretical value of the supply water temperature difference ratio includes: Calculate the difference between the measured value of the water supply temperature difference ratio and the theoretical value of the water supply temperature difference ratio, and calculate the ratio of the absolute value of the difference to the theoretical value of the water supply temperature difference ratio to obtain the deviation range of the water supply temperature difference ratio; Based on the deviation of the supply water temperature difference ratio, diagnose whether the outlet water temperature sensor is malfunctioning.

4. The method according to claim 3, characterized in that, The step of diagnosing whether the outlet water temperature sensor is malfunctioning based on the deviation of the supply water temperature difference ratio includes: If the deviation of the supply water temperature difference ratio is greater than or equal to the first preset deviation range, the outlet water temperature sensor is diagnosed as malfunctioning. If the deviation of the water supply temperature difference ratio is less than the first preset deviation range, the water outlet temperature sensor is diagnosed as not malfunctioning.

5. The method according to claim 4, characterized in that, After diagnosing that the outlet water temperature sensor is not faulty when the deviation of the supply water temperature difference ratio is less than the first preset deviation range, the method further includes: If the deviation of the water supply temperature difference ratio is greater than or equal to the second preset deviation range, the water outlet temperature detected by the water outlet temperature sensor is corrected, and the corrected water outlet temperature is output. If the deviation of the supply water temperature difference ratio is less than the second preset deviation range, the outlet water temperature detected by the outlet water temperature sensor will be output. The second preset deviation amplitude is smaller than the first preset deviation amplitude.

6. The method according to any one of claims 1 to 5, characterized in that, After diagnosing whether the outlet water temperature sensor is malfunctioning based on the first outlet water temperature, the first inlet water temperature, the second outlet water temperature, and the second inlet water temperature, the method further includes: If the water temperature sensor is found to be functioning correctly, the water pump speed is adjusted back. Once the heat pump system is running stably again, adjust the operating parameters of the heat pump system according to the heat exchange temperature difference.

7. A fault diagnosis device for a heat pump system, comprising a processor and a memory storing program instructions, characterized in that, The processor is configured to perform a method for fault diagnosis of a heat pump system as described in any one of claims 1 to 6 when executing the program instructions.

8. A heat pump system, characterized in that, include: The refrigerant circulation loop consists of a compressor, a four-way valve, an indoor heat exchanger, a throttling device, and an outdoor heat exchanger connected by refrigerant piping. The water circulation loop is composed of an inlet pipe, the indoor heat exchanger, and an outlet pipe. The inlet pipe is equipped with a water pump, and the outlet pipe is equipped with an outlet water temperature sensor. The fault diagnosis device for a heat pump system as described in claim 7.

9. A storage medium storing program instructions, characterized in that, When the program instructions are executed, they perform the fault diagnosis method for the heat pump system as described in any one of claims 1 to 6.

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