Heat pump water heater dry burning prevention control method and device, heat pump water heater and medium

Abstract

The application provides a heat pump water heater dry burning prevention control method and device, a heat pump water heater and a computer readable storage medium, and relates to the technical field of heat pump water heaters. The method comprises the following steps: when the heat pump water heater is running, if it is detected that the water temperature of the water storage tank continues to decrease, and then it is detected that the water temperature of the water storage tank continues to increase under the condition that the water temperature continues to decrease, then whether the change rate of the smaller temperature value between the upper tank temperature and the lower tank temperature is greater than or equal to a threshold value is determined once every interval time based on the condition that the water temperature continues to increase; if the change rate is greater than or equal to the threshold value and the continuous cumulative number of times that the change rate is greater than or equal to the threshold value is greater than or equal to a number threshold value, the heat pump water heater is controlled to perform a dry burning prevention operation. The application can effectively avoid the situation that the dry burning protection is mistakenly triggered due to the abnormal change of the water temperature of the water storage tank caused by a large amount of cold water suddenly entering the water storage tank, and the accuracy and reliability of dry burning detection are improved.

Description

Technical Field

[0001] This application relates to the field of heat pump water heater technology, and more specifically, to a heat pump water heater anti-dry-burning control method, device, heat pump water heater, and computer-readable storage medium in the field of heat pump water heater technology. Background Technology

[0002] Heat pump water heaters can dry-burn when powered on in a waterless or water-scarce state, leading to compressor overheating, system overpressure, component damage, and even safety hazards. Current dry-burn protection technologies for heat pump water heaters typically use the rate of temperature rise in the tank as the criterion. For example, if the rate of temperature rise at the current ambient temperature exceeds the theoretical temperature rise threshold, it is considered dry-burning and triggers the dry-burn protection. This method is effective in most operating conditions, but it carries a significant risk of misjudgment in specific scenarios. For instance, after the heat pump water heater finishes heating and stops, a large amount of hot water is used, causing the high-temperature hot water in the tank to be completely replaced by low-temperature cold water. Subsequently, when the tank temperature drops back to the start-up hysteresis point, the heat pump water heater restarts, and the high-temperature gaseous refrigerant rapidly enters the microchannel heat exchanger to heat the cold water in the tank. During this process, due to the intense heat exchange between the cold water and the heat exchanger wall, the local water temperature rises rapidly, which may cause a momentary jump in the temperature value collected by the heat pump water heater, resulting in an abnormally high calculated rate of temperature rise, even exceeding the theoretical temperature rise threshold. Even though the water tank is actually full of water and there is no risk of dry burning, the system may still falsely report that the heat pump water heater is at risk of dry burning, thereby forcibly shutting down the heat pump water heater and seriously affecting the user's normal user experience. Summary of the Invention

[0003] This application provides a method, device, heat pump water heater, and computer-readable storage medium for preventing dry burning in a heat pump water heater. This application can ensure that the heat pump water heater can be detected for dry burning during operation and without injecting a large amount of cold water into the storage tank. This effectively avoids the situation where the water temperature in the storage tank changes abnormally due to a large amount of cold water suddenly entering the storage tank, thus erroneously triggering the dry burning protection. This significantly improves the accuracy and reliability of dry burning detection.

[0004] Firstly, a method for preventing dry burning in a heat pump water heater is provided. This method includes: when the heat pump water heater is running, detecting whether the water temperature in the storage tank continuously decreases; if the water temperature in the storage tank continuously decreases, detecting whether the water temperature in the storage tank continuously increases; if the water temperature in the storage tank continuously increases, determining at each first time interval whether a target temperature difference is greater than or equal to a temperature difference threshold corresponding to the outdoor ambient temperature, wherein the target temperature difference is the difference between the smaller of the upper and lower temperatures of the water tank at the first time and the smaller of the upper and lower temperatures of the water tank at the second time, the second time being before the first time, and the first time interval being the difference between the first and second times; if the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature, and the first consecutive cumulative number of times the target temperature difference is greater than or equal to the first number threshold, controlling the heat pump water heater to perform an anti-dry burning protection operation.

[0005] Based on the above technical solution, this application, during the operation of the heat pump water heater, first determines whether the water temperature in the storage tank of the heat pump water heater is continuously decreasing. If it is determined that the water temperature in the storage tank is continuously decreasing, it indicates that while the heat pump water heater is heating the water in the storage tank, it is also injecting a large amount of cold water into the storage tank. The large amount of cold water injected causes the water temperature in the storage tank to decrease, and dry burning detection is temporarily not performed. Subsequently, it determines whether the water temperature in the storage tank is continuously increasing. If it is determined that the water temperature in the storage tank is continuously increasing, it indicates that while the heat pump water heater is heating the water in the storage tank, it has stopped injecting cold water into the storage tank, and the storage tank is in a stable heating state. Then, based on the comparison relationship between the smaller value of the upper temperature and the lower temperature of the water tank before and after the interval and the temperature difference threshold corresponding to the outdoor ambient temperature, the heat pump water heater is tested for dry burning. If a risk of dry burning is detected in the heat pump water heater, the heat pump water heater is controlled to stop to achieve dry burning protection. As can be seen, this application can ensure that the heat pump water heater can be tested for dry burning during operation, and without the heat pump water heater injecting a large amount of cold water into the storage tank. This effectively avoids the situation where the water temperature in the storage tank changes abnormally due to a large amount of cold water suddenly entering the storage tank, which may trigger the dry burning protection. This not only improves the accuracy and reliability of dry burning detection, but also avoids unnecessary shutdowns caused by misjudgment, thereby ensuring the user's normal experience of using the heat pump water heater.

[0006] In one possible implementation, detecting whether the water temperature in the storage tank continuously decreases includes: acquiring the upper and lower temperatures of the tank at second time intervals to obtain first to fourth temperature data. The first temperature data includes the upper and lower temperatures of the tank at time T1; the second temperature data includes the upper and lower temperatures at time T1+m; the third temperature data includes the upper and lower temperatures at time T1+2m; and the fourth temperature data includes the upper and lower temperatures at time T1+3m, where m is the second time interval, and the first time interval is shorter than the second time interval. Then, it is determined whether the temperature difference between the first and third temperatures satisfies a first condition, where the first temperature difference is the difference between the larger temperature value in the second temperature data and the larger temperature value in the first temperature data; the second temperature difference is the difference between the larger temperature value in the third temperature data and the larger temperature value in the third temperature data. The first condition includes the first temperature difference being greater than or equal to the product of the first temperature increment coefficient and the second temperature difference, the second temperature difference being greater than or equal to the product of the second temperature increment coefficient and the third temperature difference, and the second temperature difference being greater than or equal to the product of the first temperature increment coefficient and the second temperature difference, and the second consecutive cumulative number of times the second temperature difference is greater than or equal to the second number threshold, and the first temperature increment coefficient and the second temperature increment coefficient are greater than 1; if the first to third temperature differences meet the first condition, it is determined that the water temperature in the storage tank is continuously decreasing; if the first to third temperature differences do not meet the first condition, it is determined that the water temperature in the storage tank is not continuously decreasing.

[0007] In one possible implementation, after determining whether the first to third temperature differences meet the first condition, the heat pump water heater anti-dry burning control method further includes: if the first to third temperature differences do not meet the first condition, performing a step of determining whether the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature every first time interval.

[0008] In one possible implementation, detecting whether the water temperature in the storage tank continuously rises includes: acquiring the upper and lower temperatures of the tank every second time interval to obtain fifth to seventh temperature data. The fifth temperature data includes the upper and lower temperatures of the tank at time T2; the sixth temperature data includes the upper and lower temperatures of the tank at time T2+m; and the seventh temperature data includes the upper and lower temperatures of the tank at time T2+2m. Time T2 is determined after the first to third temperature differences satisfy the first condition. Then, it is determined whether the fifth and sixth temperature differences satisfy the second condition, where the fifth temperature difference is the sixth temperature data. The fifth temperature difference is the difference between the smaller temperature value in the seventh temperature data and the smaller temperature value in the sixth temperature data. The sixth temperature difference is the difference between the smaller temperature value in the seventh temperature data and the smaller temperature value in the sixth temperature data. The second condition includes that the sixth temperature difference is greater than or equal to the product of the third temperature increment coefficient and the fifth temperature difference, and the third consecutive cumulative number of times the sixth temperature difference is greater than or equal to the product of the third temperature increment coefficient and the fifth temperature difference is greater than or equal to the third number threshold, and the third temperature increment coefficient is greater than 1. If the fifth temperature difference and the sixth temperature difference meet the second condition, it is determined that the water temperature in the storage tank is continuously rising. If the fifth temperature difference and the sixth temperature difference do not meet the second condition, it is determined that the water temperature in the storage tank is not continuously rising.

[0009] In one possible implementation, after determining whether the fifth temperature difference and the sixth temperature difference meet the second condition, the heat pump water heater anti-dry burning control method further includes: if the fifth temperature difference and the sixth temperature difference do not meet the second condition, the third consecutive cumulative count is cleared to zero, and the upper temperature of the water tank and the lower temperature of the water tank are obtained once every second time interval to obtain the fifth to seventh temperature data.

[0010] In one possible implementation, if the water temperature in the water tank continues to rise, determining whether the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature at each first time interval includes: if the water temperature in the water tank continues to rise, after waiting for a third time interval, determining whether the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature at each first time interval.

[0011] In one possible implementation, the heat pump water heater anti-dry-burning control method further includes: when the heat pump water heater is running, determining whether the cumulative running time of the heat pump water heater is greater than or equal to a preset running time; if the cumulative running time is greater than or equal to the preset running time, executing a step of detecting whether the water temperature in the storage tank continues to decrease; if the cumulative running time is less than the preset running time, executing a step of determining whether the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature every first time interval.

[0012] Secondly, a heat pump water heater anti-dry-burning control device is provided, the heat pump water heater anti-dry-burning control device comprising:

[0013] The first detection module is used to detect whether the water temperature in the storage tank continues to drop when the heat pump water heater is running. The second detection module is used to detect whether the water temperature in the water tank continues to rise when the water temperature in the water tank continues to decrease. The temperature judgment module is used to determine whether the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature once every first time interval when the water temperature in the water tank continues to rise. The target temperature difference is the difference between the smaller value of the upper temperature and the lower temperature of the water tank at the first time and the smaller value of the upper temperature and the lower temperature of the water tank at the second time. The second time is before the first time, and the first time interval is the difference between the first time and the second time. The safety protection module is used to control the heat pump water heater to perform anti-dry burning protection operation if the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature, and the first consecutive cumulative number of times the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature is greater than or equal to the first number threshold.

[0014] Thirdly, a heat pump water heater is provided, including a memory and a processor. The memory is used to store executable program code, and the processor is used to call and run the executable program code from the memory, causing the heat pump water heater to perform the heat pump water heater anti-dry-burning control method in the first aspect or any possible implementation thereof.

[0015] Fourthly, a computer program product is provided, comprising: computer program code, which, when executed on a computer, causes the computer to perform the heat pump water heater anti-dry-burning control method described in the first aspect or any possible implementation thereof.

[0016] Fifthly, a computer-readable storage medium is provided, which stores computer program code that, when executed on a computer, causes the computer to perform the heat pump water heater anti-dry-burning control method described in the first aspect or any possible implementation thereof. Attached Figure Description

[0017] Figure 1 This paper presents a schematic flowchart of a heat pump water heater anti-dry-burning control method according to an embodiment of the present application; Figure 2 This application provides a system schematic diagram of a heat pump water heater according to an embodiment of the present application; Figure 3 This paper shows another schematic flowchart of a heat pump water heater anti-dry burning control method provided in an embodiment of this application; Figure 4 This illustration shows a structural schematic diagram of a heat pump water heater anti-dry-burning control device provided in an embodiment of this application; Figure 5 A schematic diagram of the structure of a heat pump water heater provided in an embodiment of this application is shown. Detailed Implementation

[0018] The technical solutions in this application will be clearly and thoroughly described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B. "And / or" in the text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more than two.

[0019] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0020] Heat pump water heaters can dry-burn when powered on in a waterless or water-scarce state, leading to compressor overheating, system overpressure, component damage, and even safety hazards. Current dry-burn protection technologies for heat pump water heaters typically use the rate of temperature rise in the tank as the criterion. For example, if the rate of temperature rise at the current ambient temperature exceeds the theoretical temperature rise threshold, it is considered dry-burning and triggers the dry-burn protection. This method is effective in most operating conditions, but it carries a significant risk of misjudgment in specific scenarios. For instance, after the heat pump water heater finishes heating and stops, a large amount of hot water is used, causing the high-temperature hot water in the tank to be completely replaced by low-temperature cold water. Subsequently, when the tank temperature drops back to the start-up hysteresis point, the heat pump water heater restarts, and the high-temperature gaseous refrigerant rapidly enters the microchannel heat exchanger to heat the cold water in the tank. During this process, due to the intense heat exchange between the cold water and the heat exchanger wall, the local water temperature rises rapidly, which may cause a momentary jump in the temperature value collected by the heat pump water heater, resulting in an abnormally high calculated rate of temperature rise, even exceeding the theoretical temperature rise threshold. Even though the water tank is actually full of water and there is no risk of dry burning, the system may still falsely report that the heat pump water heater is at risk of dry burning, thereby forcibly shutting down the heat pump water heater and seriously affecting the user's normal user experience.

[0021] Based on the above problems, this application provides a method, device, heat pump water heater, and computer-readable storage medium for preventing dry burning in a heat pump water heater. During operation of the heat pump water heater, this application first determines whether the water temperature in the storage tank of the heat pump water heater is continuously decreasing. If the water temperature in the storage tank is continuously decreasing, it indicates that while heating the water in the storage tank, the heat pump water heater is also injecting a large amount of cold water into the storage tank. The large amount of cold water injected causes the water temperature in the storage tank to decrease, and dry burning detection is temporarily suspended. Subsequently, it determines whether the water temperature in the storage tank is continuously increasing. If the water temperature in the storage tank is continuously increasing, it indicates that while heating the water in the storage tank, the heat pump water heater has stopped injecting cold water into the storage tank. Because the injection of cold water has stopped, the storage tank is in a stable heating state. Then, dry burning detection is performed on the heat pump water heater. If a risk of dry burning is detected, the heat pump water heater is controlled to stop, thereby achieving dry burning protection. As can be seen, this application can ensure that the heat pump water heater can be tested for dry burning during operation and without the heat pump water heater injecting a large amount of cold water into the storage tank. This effectively avoids the situation where the water temperature of the storage tank changes abnormally due to a large amount of cold water suddenly entering the storage tank, which may trigger the dry burning protection. This significantly improves the accuracy and reliability of the dry burning test.

[0022] The following is an embodiment of a method for preventing dry burning in a heat pump water heater provided in this application specification.

[0023] Figure 1 This paper presents a schematic flowchart of a heat pump water heater anti-dry-burning control method provided in an embodiment of this application. The heat pump water heater is the subject executing the heat pump water heater anti-dry-burning control method provided in this embodiment of the application. Figure 2 This application provides a system schematic diagram of a heat pump water heater according to an embodiment of the present application. Figure 2 As shown, the heat pump water heater includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, an electronic expansion valve 4, a water storage tank 5, a high-pressure switch HP, a low-pressure switch LP, etc. The compressor 1, four-way valve 2, outdoor heat exchanger 3, electronic expansion valve 4, water storage tank 5, high-pressure switch HP, low-pressure switch LP, etc., are arranged according to... Figure 2 The connections are shown in the diagram. Here, Tp represents the exhaust temperature of compressor 1, Th represents the return gas temperature of compressor 1, T4 represents the outdoor ambient temperature, T3 represents the inlet evaporation temperature of outdoor heat exchanger 3, T5U represents the upper temperature of the water tank in water storage tank 5, T5L represents the lower temperature of the water tank in water storage tank 5, Twin represents the water inlet of water storage tank 5, and Tout represents the water outlet of water storage tank 5. Figure 2C, D, E, and S are the four ports of the four-way valve 2. Specifically, port C (Common) of the four-way valve 2 is connected to the outdoor heat exchanger 3; port D (Discharge) of the four-way valve 2 is connected to the exhaust port of the compressor 1; port E (Evaporator) of the four-way valve 2 is connected to the heat exchanger in the water storage tank 5; and port S (Suction) of the four-way valve 2 is connected to the return port of the compressor 1.

[0024] The principle of a heat pump water heater heating water in a tank: After the heat pump water heater starts operating, compressor 1 compresses the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure gas, which is then discharged into four-way valve 2. Four-way valve 2 guides the high-temperature, high-pressure refrigerant gas to the heat exchange coil inside the storage tank (which acts as a condenser at this time). In the heat exchange coil, the refrigerant releases heat to the cold water in the storage tank 5, thereby heating the cold water, and the refrigerant condenses into a high-pressure liquid. After the high-pressure liquid refrigerant flows out of the storage tank 5, it passes through electronic expansion valve 4 for throttling, rapidly reducing pressure and temperature, becoming a low-temperature, low-pressure refrigerant. Then, the low-temperature, low-pressure refrigerant enters the outdoor heat exchanger 3 (which acts as an evaporator at this time), absorbs heat from the outdoor air, and completely evaporates into a low-temperature, low-pressure gas. This low-temperature, low-pressure gaseous refrigerant flows through four-way valve 2 again and is guided back to compressor 1, completing a heating cycle and continuously transferring heat from the air to the storage tank 5 to achieve efficient heating.

[0025] The heat pump water heater anti-dry-burning control method provided in this application includes the following solutions: S110: When the heat pump water heater is running, detect whether the water temperature in the storage tank continues to decrease.

[0026] In an exemplary embodiment, when the heat pump water heater starts to heat the cold water in the storage tank, it first detects whether the water temperature in the storage tank continues to decrease. The purpose of detecting whether the water temperature in the storage tank continues to decrease is to determine whether the heat pump water heater is injecting a large amount of cold water into the storage tank while heating the water in the storage tank.

[0027] S120: If the water temperature in the storage tank continues to decrease, check whether the water temperature in the storage tank continues to rise.

[0028] When a continuous decrease in water temperature is detected in the storage tank, it indicates that a large amount of low-temperature cold water is being injected into the storage tank during the heating process of the heat pump water heater, causing the overall water temperature in the storage tank to drop. Therefore, detecting a continuous decrease in water temperature in the storage tank can be used as a basis for determining that the heat pump water heater is injecting a large amount of cold water into the storage tank.

[0029] After confirming that the heat pump water heater is injecting a large amount of cold water into the storage tank, the dry-burning test is temporarily suspended. Instead, the water temperature in the storage tank is checked to see if it continues to rise. By checking whether the water temperature in the storage tank continues to rise, it can be determined whether the heat pump water heater is in a stable heating state.

[0030] S130: If the water temperature in the water tank continues to rise, determine whether the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature every first time interval. The target temperature difference is the difference between the smaller value of the upper temperature and the lower temperature of the water tank at the first time and the smaller value of the upper temperature and the lower temperature of the water tank at the second time. The second time is before the first time, and the first time interval is the difference between the first time and the second time. S140: If the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature, and the first consecutive cumulative number of times the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature is greater than or equal to the first number threshold, control the heat pump water heater to perform anti-dry burning protection operation.

[0031] If the water temperature in the storage tank continues to rise, it indicates that the heat pump water heater is in a stable heating state, and it also indicates that the heat pump water heater may have stopped injecting cold water into the storage tank. Therefore, a dry-burning test should be performed on the heat pump water heater.

[0032] The process of dry-burning test of a heat pump water heater includes: setting a first duration (e.g., 3 minutes), and with the heat pump water heater already in a stable heating state, first acquiring the outdoor ambient temperature T4, the upper temperature T5U of the water tank, and the lower temperature T5L of the water tank. The acquisition time of these three temperatures is called the second time. Then, after the first duration, acquiring the outdoor ambient temperature T4, the upper temperature T5U of the water tank, and the lower temperature T5L of the water tank again is called the first time. That is, the second time is before the first time, and the first duration = the first time - the second time.

[0033] After obtaining the temperature data at the first and second time points, the smaller value between the upper temperature T5U and the lower temperature T5L of the water tank at the first and second time points is determined. Specifically, the smaller value between the upper temperature T5U and the lower temperature T5L at the first time point is T15min(t3) = min(upper temperature T5U and lower temperature T5L at the first time point), and the smaller value between the upper temperature T5U and the lower temperature T5L at the second time point is T15min(t) = min(upper temperature T5U and lower temperature T5L at the second time point). After obtaining T15min(t3) and T15min(t), the target temperature difference is expressed as V△T15min(t3), where V△T15min(t3) = T15min(t3) - T15min(t).

[0034] Different temperature difference thresholds are pre-set for different outdoor ambient temperatures T4, denoted as k. For example, if T4 < 2℃, k = x1; 2 ≤ T4 < 7℃, k = x2; 7 ≤ T4 < 25℃, k = x3; T4 ≥ 25℃, k = x4; where x1 < x2 < x3 < x4. If the current outdoor ambient temperature T4 is 24℃, k is set to x3.

[0035] After obtaining the target temperature difference V△T15min(t3), compare V△T15min(t3) with k corresponding to T4. If V△T15min(t3) ≥ k, increment the count value of the first counter (initial value is 0) by 1, at which point the total value is 1. Then, after a first time interval, obtain the outdoor ambient temperature T4, the upper temperature T5U of the water tank, and the lower temperature T5L of the water tank. This yields the outdoor ambient temperature T4, the upper temperature T5U of the water tank, and the lower temperature T5L of the water tank at the third time point. Based on the calculation process of V△T15min(t3), obtain V△T15min(t6). If V△T15min(t6)≥k, the count value of the first counter is incremented by 1, and the total value is 2. Then, after the first time interval, the outdoor ambient temperature T4, the upper temperature T5U of the water tank, and the lower temperature T5L of the water tank are obtained to obtain the outdoor ambient temperature T4, the upper temperature T5U of the water tank, and the lower temperature T5L of the water tank at the fourth time. Based on the calculation process of V△T15min(t3), V△T15min(t9) is obtained. If V△T15min(t9)≥k, the count value of the first counter is incremented by 1, and the total value is 3. And so on.

[0036] The total value of the first counter is used as the first consecutive cumulative count. If the first consecutive cumulative count is greater than or equal to the first threshold (e.g., 10 times), it means that the judgment result of the target temperature difference being greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature has occurred multiple times consecutively. Therefore, it is determined that the heat pump water heater has a risk of dry burning, and the heat pump water heater is controlled to shut down to achieve anti-dry burning protection. The purpose of comparing the first consecutive cumulative count with the first threshold is to avoid misjudging the risk of dry burning due to a single or occasional abnormal water temperature fluctuation, thereby preventing the anti-dry burning protection shutdown from being triggered erroneously.

[0037] Based on the above technical solution, this application, during the operation of the heat pump water heater, first determines whether the water temperature in the storage tank of the heat pump water heater is continuously decreasing. If it is determined that the water temperature in the storage tank is continuously decreasing, it indicates that while the heat pump water heater is heating the water in the storage tank, it is also injecting a large amount of cold water into the storage tank. The large amount of cold water injected causes the water temperature in the storage tank to decrease, and dry burning detection is temporarily not performed. Subsequently, it determines whether the water temperature in the storage tank is continuously increasing. If it is determined that the water temperature in the storage tank is continuously increasing, it indicates that while the heat pump water heater is heating the water in the storage tank, it has stopped injecting cold water into the storage tank, and the storage tank is in a stable heating state. Then, based on the comparison relationship between the smaller value of the upper temperature and the lower temperature of the water tank before and after the interval and the temperature difference threshold corresponding to the outdoor ambient temperature, the heat pump water heater is tested for dry burning. If a risk of dry burning is detected in the heat pump water heater, the heat pump water heater is controlled to stop to achieve dry burning protection. As can be seen, this application can ensure that the heat pump water heater can be tested for dry burning during operation, and without the heat pump water heater injecting a large amount of cold water into the storage tank. This effectively avoids the situation where the water temperature in the storage tank changes abnormally due to a large amount of cold water suddenly entering the storage tank, which may trigger the dry burning protection. This not only improves the accuracy and reliability of dry burning detection, but also avoids unnecessary shutdowns caused by misjudgment, thereby ensuring the user's normal experience of using the heat pump water heater.

[0038] In one possible implementation, detecting whether the water temperature in the water storage tank continues to decrease includes the following steps: The temperature at the top and bottom of the water tank is acquired every second time interval to obtain the first to fourth temperature data. Determine whether the first to third temperature differences meet the first condition. The first condition includes that the first temperature difference is greater than or equal to the product of the first temperature increment coefficient and the second temperature difference, the second temperature difference is greater than or equal to the product of the second temperature increment coefficient and the third temperature difference, and the second consecutive cumulative number of times the first temperature difference is greater than or equal to the product of the first temperature increment coefficient and the second temperature difference is greater than or equal to the second number threshold, and the first temperature increment coefficient and the second temperature increment coefficient are greater than 1. If the first to third temperature differences meet the first condition, it is determined that the water temperature in the storage tank continues to decrease. If the temperature difference between the first and third conditions does not meet the first condition, it is determined that the water temperature in the storage tank has not continued to decrease.

[0039] The specific process for detecting whether the water temperature in the storage tank is continuously decreasing is as follows: A second time interval is set, where the first time interval is shorter than the second time interval. The second time interval is denoted as m, for example, m = 5 minutes. When the heat pump water heater starts heating the cold water in the storage tank, the upper temperature T5U and lower temperature T5L of the tank are acquired once to obtain the first temperature data. The time at which this first temperature data is acquired is called time T1, meaning the first temperature data includes the upper temperature T5U and lower temperature T5L of the tank at time T1. After a second time interval, the upper temperature T5U and lower temperature T5L of the tank are acquired again to obtain the second temperature data. The time at which this second temperature data is acquired is called time T1+m, meaning the first temperature data includes the upper temperature T5U and lower temperature T5L of the tank at time T1+m. After a second time interval, the upper temperature T5U and lower temperature T5L of the water tank are acquired again to obtain the third temperature data. The acquisition time of this third temperature data is called T1+2m, which means that the third temperature data includes the upper temperature T5U and lower temperature T5L of the water tank at T1+2m. After another second time interval, the upper temperature T5U and lower temperature T5L of the water tank are acquired again to obtain the fourth temperature data. The acquisition time of this fourth temperature data is called T1+3m, which means that the fourth temperature data includes the upper temperature T5U and lower temperature T5L of the water tank at T1+3m.

[0040] After obtaining the first to fourth temperature data, calculate the largest temperature value among the first to fourth temperature data, that is, the largest temperature value in the first temperature data is T25max(t) = max(the temperature of the upper part of the water tank T5U and the temperature of the lower part of the water tank T5L at time T1), the largest temperature value in the second temperature data is T25max(t5) = max(the temperature of the upper part of the water tank T5U and the temperature of the lower part of the water tank T5L at time T1+m), the largest temperature value in the third temperature data is T25max(t10) = max(the temperature of the upper part of the water tank T5U and the temperature of the lower part of the water tank T5L at time T1+2m), and the largest temperature value in the fourth temperature data is T25max(T25) = max(the temperature of the upper part of the water tank T5U and the temperature of the lower part of the water tank T5L at time T1+3m).

[0041] After calculating the larger temperature value among the first to fourth temperature data, the first temperature difference V△T25max(t5), the second temperature difference V△T25max(t10), and the third temperature difference V△T25max(T25) are calculated, that is: V△T25max(t5)=T25max(t5)-T25max(t); V△T25max(t10)=T25max(t10)-T25max(t5); V△T25max(T25)=T25max(T25)-T25max(t10).

[0042] Let the first temperature increment coefficient be denoted as k1 and the second temperature increment coefficient be denoted as k2. Both k1 and k2 are greater than 1. k1 and k2 can be the same or different, for example, k2 > k1. After obtaining the first temperature difference V△T25max(t5), the second temperature difference V△T25max(t10), and the third temperature difference V△T25max(T25), compare V△T25max(t5) with k1×V△T25max(t10), and compare V△T25max(t10) with k2×V△T25max(T25). If V△T25max(t5)≥k1×V△T25max(t10) and V△T25max(t10)≥k2×V△T25max(T25), increment the count value of the second counter (initial value is 0) by 1. At this time, the total value is 1. Then, based on the above method of obtaining the first to fourth temperature data of the first group, obtain the second group of first to fourth temperature data. In the second group, the first... The acquisition times corresponding to the fourth temperature data are T1+3m, T1+4m, T1+5m, and T1+6m, respectively. Based on the first to fourth temperature data of the second group, the first temperature difference V△T25max(t20), the second temperature difference V△T25max(t25), and the third temperature difference V△T25max(t30) of the second group are calculated. If V△T25max(t20)≥k1×V△T25max(t25) and V△T25max(t25)≥k2×V△T25max(t30), the count value of the second counter is incremented by 1, and the total value is 2. Then, based on the above method of acquiring the first to fourth temperature data of the second group, the third group of first to fourth temperature data is acquired, and so on.

[0043] The total value of the second counter is used as the second consecutive cumulative count. If the second consecutive cumulative count is greater than or equal to the second count threshold (e.g., 5 times), it means that the first condition is met, that is, it is determined that the water temperature in the water tank is continuously decreasing. Otherwise, it means that the first condition is not met, that is, it is determined that the water temperature in the water tank is not continuously decreasing.

[0044] In one possible implementation, after determining whether the first to third temperature differences meet the first condition, the heat pump water heater anti-dry-burning control method further includes the following steps: If the first to third temperature differences do not meet the first condition, the step of determining whether the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature is executed every first time interval.

[0045] After determining that the first to third temperature differences do not meet the first condition, it is assumed that the water temperature in the storage tank has not continued to decrease. Therefore, it can be concluded that the water temperature in the storage tank may continue to rise. Thus, it no longer judges whether the water temperature in the storage tank continues to decrease, but directly executes the step of judging whether the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature every first time interval. This immediately performs dry burning detection to avoid the heat pump water heater actually dry burning, which could lead to problems such as compressor overheating, system overpressure, and component damage.

[0046] One possible implementation involves detecting whether the water temperature in the storage tank is continuously rising, including the following steps: The temperatures at the top and bottom of the water tank are collected every second time interval to obtain the fifth through seventh temperature data. Determine whether the fifth temperature difference and the sixth temperature difference satisfy the second condition, wherein the fifth temperature difference is the difference between the smaller temperature value in the sixth temperature data and the smaller temperature value in the fifth temperature data, and the sixth temperature difference is the difference between the smaller temperature value in the seventh temperature data and the smaller temperature value in the sixth temperature data. The second condition includes that the sixth temperature difference is greater than or equal to the product of the third temperature increment coefficient and the fifth temperature difference, and the third consecutive cumulative number of times the sixth temperature difference is greater than or equal to the product of the third temperature increment coefficient and the fifth temperature difference is greater than or equal to the third number threshold, and the third temperature increment coefficient is greater than 1. If the fifth and sixth temperature differences meet the second condition, it is determined that the water temperature in the storage tank continues to rise. If the fifth and sixth temperature differences do not meet the second condition, it is determined that the water temperature in the storage tank has not continued to rise.

[0047] The specific process for detecting whether the water temperature in the storage tank is continuously rising is as follows: if a continuous decrease in the water temperature in the storage tank is detected... First, the upper temperature T5U and lower temperature T5L of the water tank are acquired once to obtain the fifth temperature data. The acquisition time of this fifth temperature data is called time T2. That is, the first temperature data includes the upper temperature T5U and lower temperature T5L of the water tank at time T2. After a second time interval, the upper temperature T5U and lower temperature T5L of the water tank are acquired again to obtain the sixth temperature data. The acquisition time of this sixth temperature data is called time T2+m. That is, the sixth temperature data includes the upper temperature T5U and lower temperature T5L of the water tank at time T2+m. After another second time interval, the upper temperature T5U and lower temperature T5L of the water tank are acquired again to obtain the seventh temperature data. The acquisition time of this seventh temperature data is called time T2+2m. That is, the seventh temperature data includes the upper temperature T5U and lower temperature T5L of the water tank at time T2+2m. In this case, after determining that the first to third temperature difference meets the first condition, if we assume that the time when the first to third temperature difference meets the first condition is T1+6m+n, then the time T2 may be T1+6m+n.

[0048] After obtaining the fifth to seventh temperature data, calculate the smallest temperature value among the fifth to seventh temperature data, that is, the smallest temperature value in the fifth temperature data is T25min(t) = min (the temperature of the upper part of the water tank T5U and the temperature of the lower part of the water tank T5L at time T2), the smallest temperature value in the sixth temperature data is T25min(t5) = min (the temperature of the upper part of the water tank T5U and the temperature of the lower part of the water tank T5L at time T2+m), and the smallest temperature value in the seventh temperature data is T25min(t10) = min (the temperature of the upper part of the water tank T5U and the temperature of the lower part of the water tank T5L at time T2+2m).

[0049] After calculating the smaller temperature value among the fifth to seventh temperature data, calculate the fifth temperature difference V△T25min(t5) and the sixth temperature difference V△T25min(t10), that is: V△T25min(t5)=T25min(t5)-T25min(t); V△T25min(t10)=T25min(t10)-T25min(t5).

[0050] Let the third temperature increment coefficient be denoted as k3, and the second temperature increment coefficient be denoted as k2. k1, k2, and k3 are all greater than 1. k1, k2, and k3 can be the same or different, for example, k3 > k2 > k1. After obtaining the fifth temperature difference V△T25min(t5) and the sixth temperature difference V△T25min(t10), compare V△T25min(t10) with k3 × V△T25min(t5). If V△T25min(t10) ≥ k3 × V△T25min(t5), increment the count value of the third counter (initially 0) by 1. At this point, the total value is 1. Then, based on the above method for obtaining the first set of fifth to seventh temperature data, obtain the second set of fifth to seventh temperature data. The acquisition of the fifth to seventh temperature data in the second set... The timestamps are T2+2m, T2+3m, and T2+4m, respectively. Based on the fifth to seventh temperature data of the second group, the fifth temperature difference V△T25min(t15) and the sixth temperature difference V△T25min(t20) of the second group are calculated. If V△T25min(t20)≥k3×V△T25min(t15), the count value of the second counter is incremented by 1. At this time, the total value is 2. Then, based on the above method of obtaining the fifth to seventh temperature data of the second group, the fifth to seventh temperature data of the third group are obtained, and so on.

[0051] The total value of the third counter is used as the third consecutive cumulative count. If the third consecutive cumulative count is greater than or equal to the third count threshold (e.g., 5 times), it means that the second condition is met, that is, the water temperature in the storage tank is continuously rising. Otherwise, it means that the second condition is not met, that is, the water temperature in the storage tank is not continuously rising.

[0052] In one possible implementation, after determining whether the fifth and sixth temperature differences satisfy the second condition, the heat pump water heater anti-dry-burning control method further includes the following steps: If the fifth and sixth temperature differences do not meet the second condition, the third consecutive cumulative count is reset to zero, and the steps of obtaining the upper and lower temperatures of the water tank once every second time interval are executed to obtain the fifth to seventh temperature data.

[0053] After determining that the fifth and sixth temperature differences do not meet the second condition, it is assumed that the water temperature in the storage tank is not continuously rising. Therefore, the third consecutive cumulative count is reset to zero, meaning the total value of the third counter is cleared. The process then returns to re-execute the step of acquiring the upper and lower temperatures of the water tank every second time interval to obtain the fifth to seventh temperature data, in order to monitor in real time whether the water temperature in the storage tank is continuously rising. During this real-time monitoring of whether the water temperature in the storage tank is continuously rising, dry-burning detection is temporarily suspended.

[0054] In one possible implementation, if the water temperature in the storage tank continues to rise, determining whether the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature at each first time interval includes the following steps: If the water temperature in the storage tank continues to rise, after the third time interval, the target temperature difference is checked once every first time interval to see if it is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature.

[0055] After confirming that the water temperature in the storage tank continues to rise, the dry-burn test is not performed immediately. Instead, a third time interval (e.g., 2 minutes) is waited. After the third time interval has elapsed, the dry-burn test is then performed. This process begins from the step of judging whether the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature at each first time interval. This ensures that the dry-burn test is performed under truly stable thermal conditions, thereby avoiding misjudging the normal heating process as dry-burn and improving the accuracy and reliability of the dry-burn test.

[0056] In one possible implementation, the heat pump water heater anti-dry-burning control method further includes the following steps: When the heat pump water heater is running, determine whether the cumulative running time of the heat pump water heater is greater than or equal to the preset running time; If the cumulative runtime is greater than or equal to the preset runtime, execute the step of detecting whether the water temperature in the water tank continues to decrease. If the cumulative running time is less than the preset running time, the step of determining whether the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature is executed every first time interval.

[0057] Considering that during actual installation, if a large number of heat pump water heaters are deployed in batches, the commissioning personnel may overlook some, resulting in the water tanks of these heat pump water heaters not being filled with water. For such heat pump water heaters without water filling, if the user turns them on for the first time, the heat pump water heater will immediately enter a dry-burning state. If the dry-burning test is still performed according to the steps S110 to S140 above at this time, the timing of triggering the dry-burning protection will be significantly delayed, causing the compressor or heat exchanger in the heat pump water heater to be in a dry-burning condition for a long time without water, which can easily cause irreversible damage. Therefore, when the heat pump water heater is running, it is first necessary to determine whether the heat pump water heater is being used for the first time. The process for determining whether the heat pump water heater is being used for the first time is as follows: check whether the cumulative running time of the heat pump water heater is greater than or equal to the preset running time (e.g., 2 hours). If the cumulative running time is greater than or equal to the preset running time, it means that the heat pump water heater is not being used for the first time. If the cumulative running time is less than the preset running time, it means that the heat pump water heater is being used for the first time. If the heat pump water heater is being used for the first time, a dry-burning test is performed directly. This involves checking at regular intervals whether the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature. Normally, if the heat pump water heater is not being used for the first time, it indicates that it has been used normally before, and there is likely water in the storage tank. Therefore, dry-burning will not occur immediately after startup. Thus, if it is determined that the heat pump water heater is not being used for the first time, the step of checking whether the water temperature in the storage tank is continuously decreasing begins from S110. This is to avoid the possibility of a sudden influx of cold water into the storage tank causing abnormal water temperature changes and falsely triggering the dry-burning protection.

[0058] The following is another embodiment of a method for preventing dry burning in a heat pump water heater provided in this application specification.

[0059] Figure 3 Another schematic flowchart of a heat pump water heater anti-dry-burning control method provided in an embodiment of this application is shown, such as... Figure 3 As shown in the embodiments of this application, the heat pump water heater anti-dry-burning control method includes the following solutions: S210: When the heat pump water heater is running, determine whether the cumulative running time of the heat pump water heater is greater than or equal to the preset running time. If yes, execute S211; if no, execute S215. S211: Acquire the temperature of the upper part of the water tank and the temperature of the lower part of the water tank every second time interval to obtain the first to fourth temperature data; S212: Determine whether the first to third temperature differences meet the first condition. If yes, execute S213; if no, execute S215. Wherein, the first temperature difference is the difference between the larger temperature value in the second temperature data and the larger temperature value in the first temperature data, the second temperature difference is the difference between the larger temperature value in the third temperature data and the larger temperature value in the second temperature data, and the third temperature difference is the difference between the larger temperature value in the fourth temperature data and the larger temperature value in the third temperature data. The first condition includes the first temperature difference being greater than or equal to the product of the first temperature increment coefficient and the second temperature difference, the second temperature difference being greater than or equal to the product of the second temperature increment coefficient and the third temperature difference, and the second consecutive cumulative number of times the second temperature difference is greater than or equal to the second number threshold, and the first temperature increment coefficient and the second temperature increment coefficient are greater than or equal to 1. S213: Acquire the temperature of the upper part of the water tank and the temperature of the lower part of the water tank every second time interval to obtain the fifth to seventh temperature data; S214: Determine whether the fifth temperature difference and the sixth temperature difference satisfy the second condition. If yes, execute S215; if no, clear the third consecutive cumulative count to zero and execute S213. Wherein, the fifth temperature difference is the difference between the smaller temperature value in the sixth temperature data and the smaller temperature value in the fifth temperature data, and the sixth temperature difference is the difference between the smaller temperature value in the seventh temperature data and the smaller temperature value in the sixth temperature data. The second condition includes the sixth temperature difference being greater than or equal to the product of the third temperature increment coefficient and the fifth temperature difference, and the sixth temperature difference being greater than or equal to the product of the third temperature increment coefficient and the fifth temperature difference, the third consecutive cumulative count being greater than or equal to the third number threshold, and the third temperature increment coefficient being greater than 1. S215: At each first time interval, determine whether the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature. The target temperature difference is the difference between the smaller value of the upper temperature and the lower temperature of the water tank at the first time and the smaller value of the upper temperature and the lower temperature of the water tank at the second time. The second time is before the first time, and the first time interval is the difference between the first time and the second time. S216: If the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature, and the first consecutive cumulative number of times the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature is greater than or equal to the first number threshold, control the heat pump water heater to perform anti-dry burning protection operation.

[0060] By performing the steps S210 to S216 above, this application can ensure that the heat pump water heater can be tested for dry burning during operation and without the heat pump water heater injecting a large amount of cold water into the storage tank. This effectively avoids the situation where the water temperature in the storage tank changes abnormally due to a large amount of cold water suddenly entering the storage tank, thus erroneously triggering the dry burning protection. This not only improves the accuracy and reliability of dry burning detection, but also avoids unnecessary shutdowns caused by misjudgment, thereby ensuring the user's normal experience of using the heat pump water heater.

[0061] The following are embodiments of the apparatus described in this application, which can be used to execute the embodiments of the method described in this application. For details not disclosed in the apparatus embodiments of this application, please refer to the embodiments of the method described in this application.

[0062] Figure 4 This application provides a schematic diagram of the structure of a heat pump water heater anti-dry-burning control device according to an embodiment of the present application. Figure 4 As shown, the heat pump water heater anti-dry-burning control device 400 includes: The first detection module 410 is used to detect whether the water temperature in the storage tank continues to decrease when the heat pump water heater is running. The second detection module 420 is used to detect whether the water temperature in the water tank continues to rise when the water temperature in the water tank continues to decrease. The temperature judgment module 430 is used to determine whether the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature once every first time interval when the water temperature in the water tank continues to rise. The target temperature difference is the difference between the smaller value of the upper temperature and the lower temperature of the water tank at the first time and the smaller value of the upper temperature and the lower temperature of the water tank at the second time. The second time is before the first time, and the first time interval is the difference between the first time and the second time. The safety protection module 440 is used to control the heat pump water heater to perform anti-dry burning protection operation if the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature, and the first consecutive cumulative number of times the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature is greater than or equal to the first number threshold.

[0063] In one possible implementation, the first detection module, specifically 410, is used to acquire the upper and lower temperatures of the water tank at second time intervals to obtain first to fourth temperature data. The first temperature data includes the upper and lower temperatures of the water tank at time T1; the second temperature data includes the upper and lower temperatures of the water tank at time T1+m; the third temperature data includes the upper and lower temperatures of the water tank at time T1+2m; and the fourth temperature data includes the upper and lower temperatures of the water tank at time T1+3m, where m is the second time interval, and the first time interval is shorter than the second time interval. The module then determines whether the first to third temperature differences satisfy a first condition, where the first temperature difference is the difference between the larger temperature value in the second temperature data and the larger temperature value in the first temperature data; the second temperature difference is the difference between the larger temperature value in the third temperature data and the larger temperature value in the third temperature data. The first condition includes the first temperature difference being greater than or equal to the product of the first temperature increment coefficient and the second temperature difference, the second temperature difference being greater than or equal to the product of the second temperature increment coefficient and the third temperature difference, and the second temperature difference being greater than or equal to the product of the first temperature increment coefficient and the second temperature difference, and the second consecutive cumulative number of times the second temperature difference is greater than or equal to the second number threshold, and the first temperature increment coefficient and the second temperature increment coefficient are greater than 1; if the first to third temperature differences meet the first condition, it is determined that the water temperature in the storage tank is continuously decreasing; if the first to third temperature differences do not meet the first condition, it is determined that the water temperature in the storage tank is not continuously decreasing.

[0064] In one possible implementation, the first detection module, specifically 410, is used to perform a step of judging whether the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature once every first time interval if the first to third temperature differences do not meet the first condition.

[0065] In one possible implementation, the second detection module, specifically 420, acquires the upper and lower temperatures of the water tank at every second time interval to obtain fifth to seventh temperature data. The fifth temperature data includes the upper and lower temperatures of the water tank at time T2; the sixth temperature data includes the upper and lower temperatures of the water tank at time T2+m; and the seventh temperature data includes the upper and lower temperatures of the water tank at time T2+2m. At time T2, after determining that the first to third temperature differences satisfy the first condition, it judges whether the fifth and sixth temperature differences satisfy the second condition. The fifth temperature difference is determined from the sixth temperature data... The difference between the smaller temperature value and the smaller temperature value in the fifth temperature data, and the difference between the smaller temperature value in the seventh temperature data and the smaller temperature value in the sixth temperature data. The second condition includes that the sixth temperature difference is greater than or equal to the product of the third temperature increment coefficient and the fifth temperature difference, and the third consecutive cumulative number of times the sixth temperature difference is greater than or equal to the product of the third temperature increment coefficient and the fifth temperature difference is greater than or equal to the third number threshold, and the third temperature increment coefficient is greater than 1. If the fifth temperature difference and the sixth temperature difference meet the second condition, it is determined that the water temperature in the storage tank is continuously rising; if the fifth temperature difference and the sixth temperature difference do not meet the second condition, it is determined that the water temperature in the storage tank is not continuously rising.

[0066] In one possible implementation, the second detection module, specifically 420, is used to clear the third consecutive cumulative count to zero if the fifth temperature difference and the sixth temperature difference do not meet the second condition, and to perform the step of acquiring the upper temperature and lower temperature of the water tank once every second time interval to obtain the fifth to seventh temperature data.

[0067] In one possible implementation, the temperature judgment module 430 is specifically used to determine whether the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature every first time interval after waiting for a third time period if the water temperature in the water storage tank continues to rise.

[0068] In one possible implementation, the heat pump water heater anti-dry-burning control device 400 further includes: The detection decision unit is used to determine whether the cumulative running time of the heat pump water heater is greater than or equal to the preset running time when the heat pump water heater is running; if the cumulative running time is greater than or equal to the preset running time, the step of detecting whether the water temperature in the storage tank continues to decrease is executed; if the cumulative running time is less than the preset running time, the step of determining whether the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature is executed every first time interval.

[0069] It should be noted that the heat pump water heater anti-dry-burning control device provided in the above embodiments is only illustrated by the division of the above functional modules when executing the heat pump water heater anti-dry-burning control method. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. In addition, the heat pump water heater anti-dry-burning control device and the heat pump water heater anti-dry-burning control method embodiments provided in the above embodiments belong to the same concept. Therefore, for details not disclosed in the device embodiments of this application, please refer to the embodiments of the heat pump water heater anti-dry-burning control method of this application, which will not be repeated here.

[0070] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0071] Figure 5 This application provides a schematic diagram of the structure of a heat pump water heater according to an embodiment of the present application. Figure 5 As shown, the heat pump water heater 500 includes a memory 501 and a processor 502. The memory 501 stores executable program code 5011, and the processor 502 is used to call and execute the executable program code 5011 to perform a heat pump water heater anti-dry burning control method.

[0072] This embodiment can divide the heat pump water heater into functional modules according to the above method example. For example, each function can be assigned to a separate module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware. It should be noted that the module division in this embodiment is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods.

[0073] By dividing the functions into modules corresponding to each function, the heat pump water heater may include: a first detection module, a second detection module, a temperature judgment module, a safety protection module, etc. It should be noted that all relevant content of each step involved in the above method embodiments can be referenced from the functional descriptions of the corresponding functional modules, and will not be repeated here.

[0074] The heat pump water heater provided in this embodiment is used to implement the above-mentioned heat pump water heater anti-dry burning control method, and therefore can achieve the same effect as the above implementation method.

[0075] When using integrated units, a heat pump water heater may include a processing module and a storage module. The processing module is used to control and manage the operation of the heat pump water heater. The storage module supports the heat pump water heater in executing relevant program code and data.

[0076] The processing module may be a processor or a controller, which can implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. The processor may also be a combination of functions that implement computing capabilities, such as a combination of one or more microprocessors, a combination of digital signal processing (DSP) and a microprocessor, etc., and the storage module may be a memory.

[0077] This embodiment also provides a computer-readable storage medium storing computer program code. When the computer program code is run on a computer, the computer executes the above-described related method steps to implement a heat pump water heater anti-dry-burning control method in the above embodiment.

[0078] This embodiment also provides a computer program product. When the computer program product is run on a computer, it causes the computer to perform the above-mentioned related steps to realize a heat pump water heater anti-dry burning control method in the above embodiment.

[0079] In addition, the heat pump water heater provided in the embodiments of this application may specifically be a chip, component or module. The heat pump water heater may include a connected processor and a memory. The memory is used to store instructions. When the heat pump water heater is running, the processor can call and execute the instructions to make the chip execute a heat pump water heater anti-dry burning control method in the above embodiments.

[0080] In this embodiment, the heat pump water heater, computer-readable storage medium, computer program product or chip are all used to execute the corresponding heat pump water heater anti-dry burning control method provided above. Therefore, the beneficial effects that can be achieved can be referred to the beneficial effects in the corresponding heat pump water heater anti-dry burning control method provided above, and will not be repeated here.

[0081] Through the above description of the embodiments, those skilled in the art will understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0082] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules or units is only 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 device, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0083] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for preventing dry burning in a heat pump water heater, characterized in that, The heat pump water heater anti-dry-burning control method includes: When the heat pump water heater is running, check whether the water temperature in the storage tank continues to drop; If the water temperature in the water storage tank continues to decrease, detect whether the water temperature in the water storage tank continues to rise; If the water temperature in the water tank continues to rise, the target temperature difference is determined once every first time interval to be greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature. The target temperature difference is the difference between the smaller value of the upper temperature and the lower temperature of the water tank at the first time interval and the smaller value of the upper temperature and the lower temperature of the water tank at the second time interval. The second time interval is before the first time interval, and the first time interval is the difference between the first time interval and the second time interval. If the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature, and the first consecutive cumulative number of times the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature is greater than or equal to the first number threshold, the heat pump water heater is controlled to perform anti-dry burning protection operation.

2. The method for preventing dry burning in a heat pump water heater according to claim 1, characterized in that, The method of detecting whether the water temperature in the water storage tank continues to decrease includes: The temperature of the upper part of the water tank and the temperature of the lower part of the water tank are acquired once every second time interval to obtain the first to fourth temperature data. The first temperature data includes the temperature of the upper part of the water tank and the temperature of the lower part of the water tank at time T1, the second temperature data includes the temperature of the upper part of the water tank and the temperature of the lower part of the water tank at time T1+m, the third temperature data includes the temperature of the upper part of the water tank and the temperature of the lower part of the water tank at time T1+2m, and the fourth temperature data includes the temperature of the upper part of the water tank and the temperature of the lower part of the water tank at time T1+3m, where m is the second time interval, and the first time interval is less than the second time interval. Determine whether the first to third temperature differences satisfy the first condition, wherein the first temperature difference is the difference between the larger temperature value in the second temperature data and the larger temperature value in the first temperature data, the second temperature difference is the difference between the larger temperature value in the third temperature data and the larger temperature value in the second temperature data, and the third temperature difference is the difference between the larger temperature value in the fourth temperature data and the larger temperature value in the third temperature data. The first condition includes the first temperature difference being greater than or equal to the product of the first temperature increment coefficient and the second temperature difference, the second temperature difference being greater than or equal to the product of the second temperature increment coefficient and the third temperature difference, and the second consecutive cumulative number of times the second temperature difference is greater than or equal to the product of the second temperature increment coefficient and the third temperature difference being greater than or equal to the second number threshold, and the first temperature increment coefficient and the second temperature increment coefficient being greater than 1. If the first to third temperature differences meet the first condition, it is determined that the water temperature in the water storage tank continues to decrease; If the first to third temperature differences do not meet the first condition, it is determined that the water temperature in the water storage tank has not continued to decrease.

3. The method for preventing dry burning in a heat pump water heater according to claim 2, characterized in that, After determining whether the first to third temperature differences meet the first condition, the heat pump water heater anti-dry-burning control method further includes: If the first to third temperature differences do not meet the first condition, the step of determining whether the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature is executed at each first time interval.

4. The method for preventing dry burning in a heat pump water heater according to claim 2, characterized in that, The step of detecting whether the water temperature in the water storage tank continues to rise includes: The temperature of the upper part of the water tank and the temperature of the lower part of the water tank are acquired once every second time interval to obtain the fifth to seventh temperature data. The fifth temperature data includes the temperature of the upper part of the water tank and the temperature of the lower part of the water tank at time T2, the sixth temperature data includes the temperature of the upper part of the water tank and the temperature of the lower part of the water tank at time T2+m, and the seventh temperature data includes the temperature of the upper part of the water tank and the temperature of the lower part of the water tank at time T2+2m. The time T2 is after the time when the first to third temperature differences are determined to meet the first condition. Determine whether the fifth temperature difference and the sixth temperature difference satisfy the second condition, wherein the fifth temperature difference is the difference between the smaller temperature value in the sixth temperature data and the smaller temperature value in the fifth temperature data, and the sixth temperature difference is the difference between the smaller temperature value in the seventh temperature data and the smaller temperature value in the sixth temperature data. The second condition includes that the sixth temperature difference is greater than or equal to the product of the third temperature increment coefficient and the fifth temperature difference, and the third consecutive cumulative number of times the sixth temperature difference is greater than or equal to the product of the third temperature increment coefficient and the fifth temperature difference is greater than or equal to the third number threshold, and the third temperature increment coefficient is greater than 1. If the fifth temperature difference and the sixth temperature difference satisfy the second condition, it is determined that the water temperature in the water storage tank continues to rise. If the fifth temperature difference and the sixth temperature difference do not meet the second condition, it is determined that the water temperature in the water storage tank has not continued to rise.

5. The method for preventing dry burning in a heat pump water heater according to claim 4, characterized in that, After determining whether the fifth and sixth temperature differences meet the second condition, the heat pump water heater anti-dry-burning control method further includes: If the fifth temperature difference and the sixth temperature difference do not meet the second condition, the third consecutive cumulative count is cleared to zero, and the step of obtaining the upper temperature of the water tank and the lower temperature of the water tank once every second time interval is executed to obtain the fifth to seventh temperature data.

6. The method for preventing dry burning in a heat pump water heater according to any one of claims 1 to 5, characterized in that, If the water temperature in the water tank continues to rise, determining whether the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature at each first time interval includes: If the water temperature in the water storage tank continues to rise, after waiting for a third period of time, the target temperature difference is determined once every first period of time to be greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature.

7. The method for preventing dry burning in a heat pump water heater according to any one of claims 1 to 5, characterized in that, The heat pump water heater anti-dry-burning control method also includes: When the heat pump water heater is running, determine whether the cumulative running time of the heat pump water heater is greater than or equal to the preset running time; If the cumulative runtime is greater than or equal to the preset runtime, the step of detecting whether the water temperature in the water storage tank continues to decrease is executed. If the cumulative running time is less than the preset running time, the step of determining whether the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature is executed every first time interval.

8. A heat pump water heater anti-dry-burning control device, characterized in that, The heat pump water heater anti-dry-burning control device includes: The first detection module is used to detect whether the water temperature in the storage tank continues to drop when the heat pump water heater is running. The second detection module is used to detect whether the water temperature in the water storage tank continues to rise when the water temperature in the water storage tank continues to decrease. The temperature judgment module is used to determine whether the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature once every first time interval when the water temperature in the water tank continues to rise. The target temperature difference is the difference between the smaller value of the upper temperature and the lower temperature of the water tank at the first time and the smaller value of the upper temperature and the lower temperature of the water tank at the second time. The second time is before the first time, and the first time interval is the difference between the first time and the second time. The safety protection module is used to control the heat pump water heater to perform anti-dry burning protection operation if the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature, and the first consecutive cumulative number of times the target temperature difference is greater than or equal to the temperature difference threshold corresponding to the outdoor ambient temperature is greater than or equal to the first number threshold.

9. A heat pump water heater, characterized in that, The heat pump water heater includes: Memory, used to store executable program code; A processor is configured to call and run the executable program code from the memory, causing the heat pump water heater to perform the heat pump water heater anti-dry burning control method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed, implements the heat pump water heater anti-dry-burning control method as described in any one of claims 1 to 7.

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