Defrosting control method of heat pump water heater and water heater

Abstract

The invention relates to the field of heat pump water heaters, in particular to a defrosting control method of a heat pump water heater and the water heater, and aims to solve the problem of inaccurate defrosting opportunity control such as untimely defrosting or lagging defrosting during defrosting control of the heat pump water heater. In order to achieve the purpose, the defrosting control method of the heat-pump water heater comprises the steps that when the heat-pump water heater runs, a defrosting judgment program is executed so as to determine whether the defrosting program is executed or not; if the defrosting program is executed, the current defrosting duration is recorded after defrosting is completed; the current defrosting duration is compared with a defrosting duration threshold value; and selectively adjusting the current defrosting judgment program according to the comparison result. By means of the technical scheme, when the heat pump water heater operates, after defrosting is conducted every time, the next defrosting judgment program is optimized, and therefore the defrosting judgment program can be more accurate.

Description

Technical Field

[0001] The invention relates to the field of heat pump water heaters, and in particular provides a defrosting control method for a heat pump water heater and a water heater. Background Art

[0002] During the use of heat pump water heaters, when the outdoor temperature is low and the humidity is high, the surface of the evaporator is prone to frost, which affects the heat exchange. The frost layer will also increase the thermal resistance on the air side and reduce the air volume, thereby reducing the heating capacity and increasing energy consumption. The water heating time becomes longer, affecting the user experience, and in severe cases, the unit cannot operate. Therefore, it is necessary to start the defrost program when the evaporator is frosted.

[0003] In the prior art, the control logic of the defrost control method of the heat pump water heater is to collect and detect the index data of the equipment operation to determine whether defrosting is required. At present, the more commonly used defrosting method is the four-way valve reversing defrosting. The judgment condition is generally that the compressor has accumulated a certain length of operation, or the evaporator coil has reached a certain temperature, and the defrosting action is performed based on a comprehensive judgment. However, since the existing defrost control of the heat pump water heater cannot respond in time when facing complex working conditions or sudden working conditions, it is easy to have defrosting lag or defrosting early. This is because the defrosting is not accurate, which will lead to a poor user experience and high power consumption of the heat pump water heater.

[0004] Accordingly, the art requires a defrost control method for a heat pump water heater to solve the above problems. Summary of the invention

[0005] The present invention aims to solve the above technical problem, that is, to solve the problem of inaccurate defrosting timing control of heat pump water heaters in the prior art, such as premature defrosting or delayed defrosting. To this end, the present invention provides a defrosting control method for a heat pump water heater, which comprises:

[0006] executing a defrost determination procedure when the heat pump water heater is running to determine whether to execute a defrost procedure;

[0007] If the defrost procedure is executed, the current defrost duration will be recorded after the defrost is completed;

[0008] Compare the current defrost duration with the defrost duration threshold;

[0009] The current defrost determination procedure is selectively adjusted according to the comparison result.

[0010] In the above-mentioned specific implementation of the defrost control method for a heat pump water heater, the defrost time threshold includes a first defrost time threshold and a second defrost time threshold, the first defrost time threshold is greater than the second defrost time threshold, and the step of "selectively adjusting the current defrost judgment procedure according to the comparison result" is specifically:

[0011] If the current defrost duration is greater than the first defrost duration threshold, the conditions of the defrost judgment procedure are relaxed;

[0012] If the current defrost duration is less than the second defrost duration threshold, tightening the conditions of the defrost judgment procedure;

[0013] If the current defrost duration is within the interval between the first defrost duration threshold and the second defrost duration threshold, the condition of the current defrost determination procedure is maintained.

[0014] In the above specific implementation of the defrost control method for a heat pump water heater, the heat pump water heater includes a compressor and a coil evaporator; the defrost judgment procedure includes:

[0015] Obtaining the operating time of the compressor and the coil temperature of the coil evaporator;

[0016] The defrost procedure is performed based on the operating time and coil temperature.

[0017] In the above specific implementation of the defrost control method for a heat pump water heater, the step of "determining whether to execute the defrost procedure according to the running time and the coil temperature" is specifically:

[0018] Determine whether the operating time is greater than the defrosting operating time threshold;

[0019] If not, continue to execute the defrost determination procedure while the heat pump water heater is running;

[0020] If the condition is satisfied, determine whether the coil temperature is less than the defrost coil temperature threshold; if not, continue to execute the defrost determination procedure when the heat pump water heater is running; if the condition is satisfied, determine whether to execute the defrost procedure based on the degree of attenuation of the coil temperature.

[0021] In the specific implementation of the defrost control method for the heat pump water heater, the step of "determining whether to execute the defrost procedure according to the attenuation degree of the coil temperature" specifically includes:

[0022] Obtaining a first coil temperature of the coil evaporator at a first moment and a second coil temperature of the coil evaporator at a second moment;

[0023] It is determined whether the difference between the first coil temperature and the second coil temperature is greater than the coil temperature attenuation threshold; if not, the defrost determination procedure is continued to be executed when the heat pump water heater is running; if satisfied, the defrost procedure is executed.

[0024] In the above specific implementation of the defrost control method for a heat pump water heater, the step of "relaxing the conditions of the defrost judgment procedure" is specifically:

[0025] The defrost operation duration threshold is reduced by T1, and / or

[0026] The defrost coil temperature threshold is increased by T2, and / or

[0027] The coil temperature decay threshold is increased by T3.

[0028] In the above specific implementation of the defrost control method for a heat pump water heater, the step of "tightening the conditions of the defrost judgment procedure" is specifically:

[0029] The defrost operation duration threshold is increased by T4, and / or

[0030] The defrost coil temperature threshold is reduced by T5, and / or

[0031] The coil temperature decay threshold is reduced by T6.

[0032] In the above specific implementation of the defrost control method for a heat pump water heater, the step of "executing a defrost determination procedure to determine whether to execute a defrost procedure" further includes:

[0033] Execute the defrost judgment procedure, and decide whether to execute the wrong defrost judgment procedure according to the defrost judgment result;

[0034] If the false defrost judgment procedure is executed, the exhaust port temperature of the compressor is obtained, and based on the exhaust port temperature, it is determined whether the exhaust attenuation condition is met. If so, the defrost procedure is executed; if not, the defrost judgment procedure continues to be executed while the heat pump water heater is running.

[0035] In a specific embodiment of the defrost control method for a heat pump water heater, the heat pump water heater further includes a heat exchange water tank; the step of "determining whether the exhaust attenuation condition is met based on the exhaust port temperature" further includes:

[0036] Obtaining the water temperature in the water exchange water tank;

[0037] It is determined whether the difference between the exhaust port temperature and the water temperature is less than the false defrost temperature attenuation threshold; if not, it is not satisfied, otherwise, it is satisfied.

[0038] A water heater comprises a storage medium storing an executable program and a processor, wherein the executable program is suitable for being loaded and run by the processor to implement the defrost control method for a heat pump water heater described in any one of the above schemes.

[0039] In the case of adopting the above-mentioned technical scheme, the defrost control method of the heat pump water heater proposed in the present invention, during operation, determines whether to execute the defrost program by collecting the parameters of the heat pump water heater, and performs the defrost program when the heat pump water heater meets the defrost conditions. After the defrost program is completed, the defrost time of the main body is recorded as the current defrost time, and the current defrost time is compared with the defrost time threshold. According to the comparison result, the defrost judgment program to be performed again is adjusted, so that the next defrost program can be carried out timely and accurately. The present invention can optimize the next defrost judgment program after each defrost when the heat pump water heater is running, so that the defrost judgment program can be more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings, in which:

[0041] Figure 1 It is a schematic diagram of the main steps of the control method in the present invention;

[0042] Figure 2 is a schematic diagram of steps of one embodiment of the control method of the present invention, wherein the steps of adjusting the defrost determination program in the control method are shown;

[0043] Figure 3 is a schematic diagram of steps of one embodiment of the control method of the present invention, wherein the steps of a specific defrosting judgment procedure in the control method are shown;

[0044] Figure 4 is a schematic diagram of steps of one embodiment of the control method of the present invention, wherein specific defrost judgment program adjustment steps in the control method are shown;

[0045] Figure 5 It is a schematic diagram of the steps of one embodiment of the control method in the present invention, which shows the specific wrong defrost judgment program steps in the control method. DETAILED DESCRIPTION

[0046] The preferred embodiments of the present invention are described below with reference to the accompanying drawings and in combination with a heat pump water heater. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not used to limit the scope of protection of the present invention. Those skilled in the art can make adjustments to them as needed to adapt to specific application scenarios.

[0047] It should be noted that in the description of the present invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the relevant devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, ordinal numbers such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0048] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] Furthermore, in order to more clearly demonstrate the core technical solution of the present invention, the description of the well-known structure of the heat pump water heater is omitted in the following description. However, this omission is only for the convenience of description and does not mean that the heat pump water heater can be without these structures.

[0050] See also Figure 1 The present invention proposes a defrosting control method for a heat pump water heater, comprising the following steps:

[0051] S100: executing a defrost determination procedure when the heat pump water heater is running to determine whether to execute a defrost procedure;

[0052] S200: If the defrost procedure is executed, the current defrost duration is recorded after the defrost is completed;

[0053] S300: Compare the current defrost time with the defrost time threshold;

[0054] S400: Selectively adjust the current defrost determination procedure according to the comparison result.

[0055] In the present embodiment, in order to solve the problem that the heat pump water heater is in operation, the defrost judgment program, when facing complex or special working conditions, collects the parameters of the heat pump water heater for judgment and detection, and decides whether to perform the defrost program according to the judgment result. However, in the actual operation, although the defrost judgment program has very fine monitoring accuracy and feedback for the parameters of the heat pump water heater during operation, the defrost program may still be entered too early or too late. In the above situation, if it is entered too early, the system will consume unnecessary energy, resulting in an inefficient operating time period for the defrost program; if it is entered too late, the system will need to invest more energy to defrost, but the defrost effect will be slow, affecting the user experience.

[0056] Based on the above problems, the defrost control method of the present invention is further optimized. When the heat pump water heater is running, the defrost judgment program is executed. If it is judged that the heat pump water heater meets the defrost conditions, the defrost program will be executed until the defrost program ends. At this time, the defrost time is recorded as the current defrost duration, and then the current defrost duration is analyzed. The current defrost duration is compared with the defrost duration threshold. Through the comparison result of the current defrost duration and the defrost duration threshold, different adjustment methods are adopted to adjust the defrost judgment program to correct and optimize the timing of execution of the defrost program.

[0057] During the use of heat pump water heaters, factors such as the equipment's own wear and tear, environmental changes, and external erosion are taken into consideration. If the defrost judgment program is maintained at a certain standard, it is difficult to accurately judge whether the heat pump water heater has actually reached the defrost standard. Therefore, after the defrost is completed, the defrost judgment program is adjusted based on the last defrost judgment program, which can make the defrost program enter more accurately, thereby improving the user experience.

[0058] For further information, see Figure 2 , the defrost time threshold includes a first defrost time threshold and a second defrost time threshold, the first defrost time threshold is greater than the second defrost time threshold; then step S400 is specifically:

[0059] S410: If the current defrost duration is greater than the first defrost duration threshold, relax the conditions of the defrost determination procedure;

[0060] S420: If the current defrost duration is less than the second defrost duration threshold, tighten the conditions of the defrost determination procedure;

[0061] S430: If the current defrost duration is within the interval between the first defrost duration threshold and the second defrost duration threshold, the conditions of the current defrost determination procedure are maintained.

[0062] In the present embodiment, for the comparison between the current defrost time and the defrost time threshold, specifically, the defrost time threshold is divided into two different node values, namely the first defrost time threshold and the second defrost time threshold, and the first defrost time threshold is greater than the second defrost time threshold. When comparing the current defrost time with the defrost time threshold, see in which interval the current defrost time falls, thereby reflecting whether the defrost judgment program judges whether the defrost timing of the heat pump water heater is accurate and within an acceptable range. In the present embodiment, the first defrost time threshold is 10 minutes, and the second defrost time threshold is 6 minutes, but this is not restrictive, and the defrost time threshold can be set as needed.

[0063] When the current defrost duration is greater than the first defrost duration threshold, it means that the defrost judgment program causes the heat pump water heater to execute the defrost program too late, resulting in a longer time and more energy consumption for defrosting. Therefore, the defrost judgment program needs to be adjusted to relax the conditions for executing the defrost program so that the heat pump water heater can execute the defrost program earlier. Similarly, when the current defrost duration is less than the second defrost duration threshold, it means that the defrost judgment program causes the heat pump water heater to execute the defrost program too early, resulting in unnecessary energy consumption for defrosting, while the actual frosting conditions do not meet the defrost conditions. Therefore, the defrost judgment program needs to be adjusted to tighten the conditions for executing the defrost program so that the heat pump water heater can execute the defrost program later. Similarly, when the current defrost duration is between the first defrost duration threshold and the second defrost duration threshold, it is considered that the timing for executing the defrost program is the most reasonable. Therefore, there is no need to adjust the defrost judgment program.

[0064] For further information, see Figure 3 , S100 specifically means:

[0065] S110: Acquire the running time of the compressor and the coil temperature of the coil evaporator;

[0066] S120: Determine whether the operating time is greater than the defrosting operating time threshold;

[0067] S121: If the condition is not satisfied, the defrost determination procedure continues to be executed while the heat pump water heater is running;

[0068] S130: If satisfied, determine whether the coil temperature is less than the defrost coil temperature threshold;

[0069] S131: If not satisfied, continue to execute the defrost determination procedure while the heat pump water heater is running;

[0070] S140: If the conditions are met, obtain a first coil temperature of the coil evaporator at a first moment and a second coil temperature at a second moment;

[0071] S150: Determine whether the difference between the first coil temperature and the second coil temperature is greater than the coil temperature attenuation threshold;

[0072] S151: If not satisfied, continue to execute the defrost determination procedure while the heat pump water heater is running;

[0073] S160: If satisfied, execute the defrost procedure.

[0074] On the basis of the above-mentioned embodiment, the conditions of the defrost determination procedure of the heat pump system specifically determine whether to execute the defrost procedure by collecting and analyzing the operation time of the compressor and the coil temperature of the coil evaporator.

[0075] First, the compressor operation time is obtained, and the compressor operation time is compared with the defrost operation time threshold. If a certain operation time is reached, it can be preliminarily judged that the compressor operation time is sufficient to cause frost to appear on its surface. However, whether the degree of frost has reached the degree of affecting the operation of the heat pump water heater needs further judgment. At this time, the coil temperature of the coil evaporator is collected and compared with the defrost coil temperature threshold. If it is less than the defrost coil temperature threshold, it is preliminarily judged that the frost has affected the coil temperature, and the coil temperature has a certain attenuation trend. However, whether the degree of frost affecting the coil temperature at this time affects the operation of the heat pump water heater needs to be further judged in combination with the attenuation degree of the coil temperature. The first coil temperature at the first moment and the second coil temperature at the second moment are obtained. Whether the difference between the first coil temperature and the second coil temperature is greater than the coil temperature attenuation value, if it is greater than the coil temperature attenuation value, it means that frost has affected the normal operation of the coil evaporator, so the defrost program is executed. The above working process is under the condition that the judgment conditions are met. If the judgment conditions are not met, the defrost judgment program will be performed again, and the compressor operation time and the coil temperature of the coil evaporator will be continuously obtained for re-judgment.

[0076] For further information, see Figure 4 , S410 specifically includes:

[0077] If the current defrost duration is greater than the first defrost duration threshold, the defrost operation duration threshold is reduced by T1, and / or

[0078] The defrost coil temperature threshold is increased by T2, and / or

[0079] The coil temperature decay threshold is increased by T3.

[0080] S420 is specifically:

[0081] If the current defrost duration is less than the second defrost duration threshold, the defrost operation duration threshold is increased by T4, and / or

[0082] The defrost coil temperature threshold is reduced by T5, and / or

[0083] The coil temperature decay threshold is reduced by T6.

[0084] On the basis of the above embodiment, the parameters in the defrost judgment program are adjusted, and the adjusted parameters are at least one of the defrost operation duration threshold, the defrost coil temperature threshold and the coil temperature attenuation threshold. It should be noted that this is not restrictive. Depending on the different values ​​collected in the defrost judgment program, the adjusted parameters are also different. Based on the above embodiment, the three items are relaxed or tightened parameter adjustments, and the defrost judgment program conditions are relaxed. In this embodiment, the defrost operation duration threshold can be reduced by 10 minutes; the defrost coil temperature threshold can be increased by 0.5°C; the coil temperature attenuation threshold can be increased by 0.2°C, so that the defrost program can be executed in advance. At least one of the above three relaxed conditions can be adjusted.

[0085] Similarly, the parameters of the defrost judgment program can also be tightened and adjusted. The tightening adjustment is also for the above-mentioned parameters, but it is also not restrictive. In this embodiment, the defrost operation time threshold can be increased by 10 minutes; the defrost coil temperature threshold can be reduced by 0.5°C; the coil temperature attenuation threshold can be reduced by 0.2°C to delay the execution of the defrost program. At least one of the above three relaxation conditions can be adjusted.

[0086] For further information, see Figure 5 The S160 also includes:

[0087] S161: If the conditions are met, executing the false defrost judgment procedure, obtaining the exhaust port temperature of the compressor, and obtaining the water temperature in the water exchange water tank;

[0088] S162: Determine whether the difference between the exhaust port temperature and the water temperature is less than the false defrost temperature attenuation threshold;

[0089] S163: If it is not less than, continuing to execute the defrost determination procedure when the heat pump water heater is running;

[0090] S164: If it is less than, execute the defrost procedure.

[0091] Based on the above embodiments, the present embodiment further optimizes the defrost judgment procedure. After judging and analyzing by collecting the parameters of the heat pump water heater, before performing the defrost procedure, a false defrost judgment procedure is further performed. It is necessary to obtain the exhaust temperature of the compressor and the temperature of the water exchange tank, and compare the difference between the exhaust temperature and the water temperature of the water exchange tank with the defrost temperature attenuation threshold. If the difference between the exhaust temperature and the water temperature of the water exchange tank is not less than the false defrost temperature attenuation threshold, it means that the heat pump water heater system can still maintain efficient heat exchange, thereby meeting the user's usage requirements, and defrosting is not necessary at this time; if the difference between the exhaust temperature and the water temperature of the water exchange tank is less than the false defrost temperature attenuation threshold, it means that the exhaust temperature is attenuated due to frost, and the exhaust temperature attenuation directly affects the operation of the heat pump water heater. Therefore, it is necessary to execute the defrost procedure so that the exhaust temperature can be raised in time, so that the heat pump water heater can achieve better heat exchange efficiency.

[0092] The present invention further proposes a water heater comprising a storage medium storing an executable program and a processor, wherein the executable program is suitable for being loaded and run by the processor to implement the defrost control method for the heat pump water heater described in any one of the above schemes.

[0093] The present embodiment also proposes a water heater, which implements the defrost control method of the heat pump water heater of the above embodiment through a storage medium and a processor. The defrost control method can be stored in a coded form in the storage medium, and the program is executed by the processor to achieve defrost control, thereby solving the problem of inaccurate defrost program of the water heater and improving the user experience.

[0094] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A defrost control method for a heat pump water heater, characterized in that: The defrost control method comprises: executing a defrost determination procedure when the heat pump water heater is running to determine whether to execute a defrost procedure; If the defrost procedure is executed, the current defrost duration will be recorded after the defrost is completed; Compare the current defrost duration with the defrost duration threshold; The current defrost determination procedure is selectively adjusted according to the comparison result.

2. The defrost control method of a heat pump water heater according to claim 1, characterized in that: The defrost time threshold includes a first defrost time threshold and a second defrost time threshold, the first defrost time threshold is greater than the second defrost time threshold, and the step of "selectively adjusting the current defrost judgment procedure according to the comparison result" is specifically as follows: If the current defrost duration is greater than the first defrost duration threshold, the conditions of the defrost judgment procedure are relaxed; If the current defrost duration is less than the second defrost duration threshold, tightening the conditions of the defrost judgment procedure; If the current defrost duration is within the interval between the first defrost duration threshold and the second defrost duration threshold, the condition of the current defrost determination procedure is maintained.

3. The defrost control method of a heat pump water heater according to claim 2, characterized in that: The heat pump water heater includes a compressor and a coil evaporator; the defrost judgment procedure includes: Obtaining the operating time of the compressor and the coil temperature of the coil evaporator; The defrost procedure is performed based on the operating time and coil temperature.

4. The defrost control method for a heat pump water heater according to claim 3, characterized in that: The steps of "Determine whether to perform the defrost procedure based on the operating time and coil temperature" are as follows: Determine whether the operating time is greater than the defrosting operating time threshold; If not, continue to execute the defrost determination procedure while the heat pump water heater is running; If it is satisfied, then determine whether the coil temperature is less than the defrost coil temperature threshold; If not, continue to execute the defrost determination procedure while the heat pump water heater is running; If it is satisfied, the defrost procedure is decided based on the degree of coil temperature decay.

5. The defrosting control method of the heat pump water heater according to claim 4, characterized in that: The steps of "determining whether to execute the defrost procedure according to the degree of attenuation of the coil temperature" specifically include: Obtaining a first coil temperature of the coil evaporator at a first moment and a second coil temperature of the coil evaporator at a second moment; Determine whether the difference between the first coil temperature and the second coil temperature is greater than a coil temperature attenuation threshold; If not, continue to execute the defrost determination procedure while the heat pump water heater is running; If satisfied, the defrost procedure is performed.

6. The defrost control method for a heat pump water heater according to claim 2, characterized in that: The specific steps of "relaxing the conditions for the defrost judgment procedure" are: The defrost operation duration threshold is reduced by T1, and / or The defrost coil temperature threshold is increased by T2, and / or The coil temperature decay threshold is increased by T3.

7. The defrost control method of a heat pump water heater according to claim 2, characterized in that: The step "tightening the conditions for the defrost judgment procedure" is as follows: The defrost operation duration threshold is increased by T4, and / or The defrost coil temperature threshold is reduced by T5, and / or The coil temperature decay threshold is reduced by T6.

8. The defrost control method for a heat pump water heater according to claim 1, characterized in that: The step of "executing a defrost determination procedure to determine whether to execute a defrost procedure" further includes: Execute the defrost judgment procedure, and decide whether to execute the wrong defrost judgment procedure according to the defrost judgment result; If the false defrost judgment procedure is executed, the exhaust port temperature of the compressor is obtained, and based on the exhaust port temperature, it is judged whether the exhaust attenuation condition is met. If it is met, the defrost procedure is executed; if it is not met, the defrost judgment procedure continues to be executed while the heat pump water heater is running.

9. The defrost control method for a heat pump water heater according to claim 8, characterized in that: The heat pump water heater also includes a heat exchange water tank; the step of "determining whether the exhaust attenuation condition is met based on the exhaust port temperature" further includes: Obtaining the water temperature in the water exchange water tank; It is determined whether the difference between the exhaust port temperature and the water temperature is less than the false defrost temperature attenuation threshold; if not, it is not satisfied, otherwise, it is satisfied.

10. A water heater, characterized in that: The water heater comprises a storage medium storing an executable program and a processor, wherein the executable program is suitable for being loaded and run by the processor to implement the defrost control method for the heat pump water heater according to any one of claims 1 to 9.

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