Defrosting control method of heat pump water heater, storage medium and water heater

Abstract

The invention relates to the field of heat-pump water heaters, particularly provides a defrosting control method of a heat-pump water heater, a storage medium and the water heater, and aims to solve the problem that defrosting errors occur due to the fact that a defrosting control method of a heat-pump water heater in the prior art cannot respond in time when facing complex working conditions or sudden working conditions. In order to achieve the purpose, the defrosting control method of the heat pump water heater is provided, the heat pump water heater comprises a compressor, and the compressor is provided with an exhaust port; the defrosting control method comprises the following steps that S1, when the heat pump water heater runs, whether a mistaken defrosting judgment program is executed or not is determined; s2, if the false defrosting judgment program is executed, the temperature of an exhaust port of a compressor is obtained; s3, whether the exhaust attenuation condition is met or not is judged based on the exhaust port temperature; s4, if yes, a defrosting program is executed; and if not, the steps S1-S3 are executed again. According to the scheme, the heat pump water heater can be prevented from entering the defrosting program too early or too late, and the heat pump water heater can better adapt to special working conditions.

Description

Technical Field

[0001] The invention relates to the field of heat pump water heaters, and specifically provides a defrosting control method for a heat pump water heater, a storage medium 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, the control logic of this method is simple, and it cannot respond to complex working conditions or sudden working conditions in time, and it is easy to fail to defrost or defrost by mistake after frosting.

[0004] Accordingly, the art needs a new defrost control method to solve the above problems. Summary of the invention The present invention aims to solve the above technical problem, that is, to solve the problem that the defrost control method of the heat pump water heater in the prior art cannot respond in time to complex working conditions or sudden working conditions, resulting in defrosting errors. To this end, the present invention provides a defrost control method for a heat pump water heater, the heat pump water heater includes a compressor, the compressor has an exhaust port; the defrost control method includes the following steps:

[0005] S1, determining whether to execute a false defrost judgment procedure when the heat pump water heater is running;

[0006] S2, if the false defrost judgment procedure is executed, obtaining the exhaust port temperature of the compressor;

[0007] S3, judging whether an exhaust attenuation condition is met based on the exhaust port temperature;

[0008] S4, if satisfied, execute the defrost procedure; if not satisfied, re-execute steps S1-S3.

[0009] In the above specific implementation of the defrost control method for a heat pump water heater, the heat pump water heater further includes a water exchange tank;

[0010] Step S3 further comprises:

[0011] Obtaining the water temperature in the water exchange water tank;

[0012] 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 it is greater, it is not satisfied; otherwise, it is satisfied.

[0013] In the specific implementation of the above-mentioned defrost control method for a heat pump water heater, step S1 further comprises:

[0014] obtaining the operating time of the compressor when the heat pump water heater is running;

[0015] Whether to execute the false defrost determination procedure is determined according to the operating time of the compressor.

[0016] In the above specific implementation of the defrost control method for a heat pump water heater, the step of "determining whether to execute the error defrost judgment procedure according to the running time of the compressor" is specifically:

[0017] Determine whether the compressor operating time is greater than the defrost operating time threshold. If so, further determine whether to execute the false defrost judgment procedure based on the first additional condition; if not, continue to obtain the compressor operating time and determine whether it is greater than the defrost operating time threshold.

[0018] In a specific embodiment of the defrost control method for a heat pump water heater, the heat pump water heater further includes a coil evaporator, and the coil evaporator exchanges heat with the heat exchange water tank; the step of "further determining whether to execute the false defrost determination procedure according to the first additional condition" further includes:

[0019] The coil temperature of the coil evaporator is obtained, and a false defrost determination procedure is selectively performed according to the coil temperature.

[0020] In the above specific implementation of the defrost control method for a heat pump water heater, the step of "selectively executing the false defrost determination procedure according to the coil temperature" is specifically:

[0021] Determine whether the coil temperature is less than the defrost coil temperature threshold. If so, execute the false defrost judgment procedure according to the second additional condition; if not, continue to obtain the compressor operation time and determine whether it is greater than the defrost operation time threshold.

[0022] In the specific implementation of the above-mentioned defrost control method for a heat pump water heater, the step of "executing the false defrost judgment procedure according to the second additional condition" further includes:

[0023] It is determined whether the coil temperature satisfies the coil temperature attenuation condition. If so, a false defrost determination procedure is executed; if not, the compressor operation time is continuously obtained and it is determined whether it is greater than a defrost operation time threshold.

[0024] In the above specific implementation of the defrost control method for a heat pump water heater, the step of "determining whether the coil temperature satisfies the coil temperature attenuation condition" is specifically:

[0025] Acquire a first coil temperature of the coil evaporator at a first moment and a second coil temperature at a second moment;

[0026] It is determined whether the difference between the first coil temperature and the second coil temperature is greater than a coil temperature attenuation threshold; if so, the coil temperature attenuation condition is met, otherwise, it is not met.

[0027] A storage medium is provided, the storage medium is suitable for storing a plurality of program codes, the program codes are suitable for being loaded and run by a processor to execute the defrost control method for a heat pump water heater described in any one of the above schemes.

[0028] A heat pump 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 described in any one of the above schemes.

[0029] In the case of adopting the above technical scheme, the defrost control method of the heat pump water heater proposed by the present invention, in addition to the judgment and analysis of the parameters of the conventional heat pump water heater system, takes into account that what really affects the heating amount of the heat pump system is the exhaust temperature of the compressor. Therefore, the exhaust port temperature of the compressor is collected and detected to determine whether it meets the exhaust attenuation condition, and the defrost program is selectively executed according to the judgment result, and when the defrost program is not met, the steps of the cycle control method are repeated. The present invention can prevent the heat pump water heater from entering the defrost program too early or too late by detecting the compressor exhaust port temperature, thereby reducing the operating efficiency of the heat pump system and wasting system operating energy, so that the heat pump water heater can better adapt to complex working conditions or sudden working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings, in which:

[0031] Figure 1 It is a schematic diagram of the main steps of the control method in the present invention;

[0032] Figure 2 It is a schematic diagram of the detailed steps of the control method in the present invention. DETAILED DESCRIPTION

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] like Figure 1 As shown, the present invention proposes a defrost control method for a heat pump water heater, wherein the heat pump water heater comprises a compressor, and the compressor has an exhaust port; the defrost control method comprises the following steps:

[0038] S100: determining whether to execute a false defrost judgment procedure when the heat pump water heater is running;

[0039] S200: if the false defrost determination procedure is executed, obtaining the exhaust port temperature of the compressor;

[0040] S300: determining whether an exhaust attenuation condition is met based on the exhaust port temperature;

[0041] S400: If the conditions are met, the defrosting procedure is performed; if not, steps S100-S300 are performed again.

[0042] Before describing the present invention, a brief description of the heat pump water heater is given for easy understanding. The heat pump water heater is a combination of a heat pump system and a water tank, which utilizes the principle of heat transfer to heat water to obtain hot water. However, as the heat pump water heater operates, frost may form. The frost layer will 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.

[0043] When the heat pump water heater is in defrosting operation, frost may form as the operating time accumulates. Therefore, the heat pump water heater needs to be defrosted. Usually, the control program is used to make a defrost judgment on the heat pump water heater and run the defrost judgment program. However, considering that there are many factors that affect the frosting judgment result during the operation of the heat pump water heater, in order to enable the heat pump water heater to defrost accurately and avoid false defrosting, considering that the main heat exchange index that really affects the heat pump water heater is the exhaust temperature, if the exhaust temperature does not decay, it can be considered that the frost is not serious and the normal operation of the heat pump water heater can be maintained to meet the normal use of the user. Therefore, it is necessary to judge the exhaust port temperature to see whether the exhaust attenuation condition is met, and then implement the false defrost judgment program. If the exhaust port temperature meets the exhaust attenuation condition, it means that the frost has affected the heat exchange of the heat pump water heater, and the defrost program is executed. If the exhaust port temperature does not meet the exhaust attenuation condition, the heat pump water heater operates normally and continues to make the defrost judgment.

[0044] Further, in some possible implementations, such as Figure 2 As shown, the defrost control method of the heat pump water heater of the present invention, the heat pump water heater also includes a heat exchange water tank; the defrost control method includes the following steps:

[0045] S100: determining whether to execute a false defrost judgment procedure when the heat pump water heater is running;

[0046] S200: if the false defrost determination procedure is executed, obtaining the exhaust port temperature of the compressor;

[0047] S310: Obtaining the water temperature in the water exchange water tank;

[0048] S320: Determine whether the difference between the exhaust port temperature and the water temperature is less than a false defrost temperature attenuation threshold;

[0049] S330: If it is greater than, it is not satisfied, and steps S100-S320 are executed again;

[0050] S400: Otherwise, the conditions are met and the defrosting procedure is executed.

[0051] In this embodiment, there are multiple ways to judge the attenuation of the exhaust port temperature. This embodiment makes a comprehensive judgment based on the water temperature in the water tank. It should be noted that other methods can also be used to collect and detect the exhaust port temperature to determine whether the exhaust attenuation conditions are met.

[0052] In this embodiment, when the heat pump water heater is in operation, in order to avoid possible false defrosting, a false defrost judgment procedure is selectively executed. Specifically, the exhaust temperature of the compressor is obtained, and during operation, the water temperature in the heat exchanger tank is obtained. The temperature difference between the exhaust temperature and the water temperature is compared with the false defrost temperature attenuation threshold to determine whether the exhaust temperature meets the exhaust attenuation. If the temperature difference between the exhaust temperature and the water temperature is less than or equal to the false defrost temperature attenuation threshold, it is considered that frosting has affected the normal operation of the heat pump water heater and defrosting is required, and the defrost procedure is executed. If the temperature difference between the exhaust temperature and the water temperature is greater than the false defrost temperature attenuation threshold, defrosting is not required, and the heat pump water heater can perform effective heat exchange to meet usage requirements.

[0053] In this embodiment, the false defrost temperature decay threshold can be set to 20°C. Using this range as the judgment standard, it can be considered that the temperature difference after heat exchange of the heat pump water heater system should be at least 20°C or above. It should be noted that this is not restrictive, and the false defrost temperature decay threshold can also take other values.

[0054] Further, in some possible implementations, continue to refer to Figure 2 The defrost control method of the heat pump water heater of the present invention comprises the following steps:

[0055] S110: obtaining the operating time of the compressor when the heat pump water heater is operating;

[0056] S120: Determine whether the compressor operation time is greater than the defrost operation time threshold;

[0057] S130: If not satisfied, continue to obtain the compressor operation time and determine whether it is greater than the defrost operation time threshold;

[0058] S140: If the condition is satisfied, further determining whether to execute the error defrost determination procedure according to the first additional condition;

[0059] S200: if the false defrost determination procedure is executed, obtaining the exhaust port temperature of the compressor;

[0060] S310: Obtaining the water temperature in the water exchange water tank;

[0061] S320: Determine whether the difference between the exhaust port temperature and the water temperature is less than a false defrost temperature attenuation threshold;

[0062] S330: If it is greater than, it is not satisfied, and steps S110-S320 are executed again;

[0063] S400: Otherwise, the conditions are met and the defrosting procedure is executed.

[0064] In this embodiment, based on the above embodiment, during the operation of the heat pump water heater, before performing the false defrost judgment procedure, a defrost program judgment needs to be performed first. Only after the defrost program determines that defrosting is necessary, a review is performed, that is, the false defrost judgment procedure.

[0065] The defrost judgment procedure is generally performed by detecting and judging the indicators directly reflected by the heat pump water heater. In the present embodiment, a possible scenario is that the operating time of the compressor is detected, and the decision on whether to perform the false defrost judgment procedure is made based on the operating time of the compressor. It is understandable that when the compressor operating time reaches a certain time, there is a high possibility that frost has formed and affected the operation of the heat pump water heater. However, it is difficult to accurately determine the degree of frost based on the operating time alone, and therefore a false defrost judgment is required.

[0066] Specifically, a threshold comparison can be used to preliminarily determine the compressor operation time, thereby serving as a judgment indicator, wherein the defrost operation time threshold can be 40 minutes. It should be noted that this is not restrictive, and the defrost operation time threshold can also take other values.

[0067] When the compressor operation time is greater than the defrost operation time threshold, it is necessary to further determine whether to execute the false defrost determination procedure through the first attachment condition, so as to make the control method more accurate.

[0068] Further, in some possible implementations, continue to refer to Figure 2 The defrost control method of the heat pump water heater of the present invention comprises the following steps:

[0069] S110: obtaining the operating time of the compressor when the heat pump water heater is operating;

[0070] S120: Determine whether the compressor operation time is greater than the defrost operation time threshold;

[0071] S130: If not satisfied, continue to obtain the compressor operation time and determine whether it is greater than the defrost operation time threshold;

[0072] S140: If the conditions are met, obtaining the coil temperature of the coil evaporator;

[0073] S141: Determine whether the coil temperature is less than a defrost coil temperature threshold;

[0074] S142: If not satisfied, continue to obtain the compressor operation time and determine whether it is greater than the defrost operation time threshold;

[0075] S143: If the condition is satisfied, executing the wrong defrost determination procedure according to the second additional condition;

[0076] S200: if the false defrost determination procedure is executed, obtaining the exhaust port temperature of the compressor;

[0077] S310: Obtaining the water temperature in the water exchange water tank;

[0078] S320: Determine whether the difference between the exhaust port temperature and the water temperature is less than a false defrost temperature attenuation threshold;

[0079] S330: If it is greater than, it is not satisfied, and steps S110-S320 are executed again;

[0080] S400: Otherwise, the conditions are met and the defrosting procedure is executed.

[0081] In this embodiment, the coil temperature of the coil evaporator may be further used as a judgment condition for the first additional condition. It should be noted that this is not restrictive, and other additional conditions may also be used as a judgment condition for whether to perform false defrosting.

[0082] Specifically, whether to execute the false defrost judgment procedure is determined by judging whether the coil temperature is lower than the defrost coil temperature threshold. The defrost coil temperature threshold is -2°C in this embodiment. It should be noted that this is not restrictive, and the defrost coil temperature threshold may also take other values.

[0083] When the coil temperature is lower than the defrost disc temperature threshold, it is considered that there is a certain amount of frost, thereby affecting the heat exchange of the coil, and further, it can be determined whether to perform the false defrost judgment procedure according to the second additional condition, thereby further improving the accuracy of the control method.

[0084] Further, in some possible implementations, continue to refer to Figure 2 The defrost control method of the heat pump water heater of the present invention comprises the following steps:

[0085] S110: obtaining the operating time of the compressor when the heat pump water heater is operating;

[0086] S120: Determine whether the compressor operation time is greater than the defrost operation time threshold;

[0087] S130: If not satisfied, continue to obtain the compressor operation time and determine whether it is greater than the defrost operation time threshold;

[0088] S140: If the conditions are met, obtaining the coil temperature of the coil evaporator;

[0089] S141: Determine whether the coil temperature is less than a defrost coil temperature threshold;

[0090] S142: If not satisfied, continue to obtain the compressor operation time and determine whether it is greater than the defrost operation time threshold;

[0091] S143: If the condition is satisfied, obtaining a first coil temperature of the coil evaporator at a first moment and a second coil temperature at a second moment;

[0092] S144: Determine whether the difference between the first coil temperature and the second coil temperature is greater than a coil temperature attenuation threshold;

[0093] S145: If it is less than, it is not satisfied, then continue to obtain the compressor operation time and determine whether it is greater than the defrost operation time threshold;

[0094] S146: Otherwise, the conditions are met, and the false defrost judgment procedure is executed;

[0095] S200: if the false defrost determination procedure is executed, obtaining the exhaust port temperature of the compressor;

[0096] S310: Obtaining the water temperature in the water exchange water tank;

[0097] S320: Determine whether the difference between the exhaust port temperature and the water temperature is less than a false defrost temperature attenuation threshold;

[0098] S330: If it is greater than, it is not satisfied, and steps S110-S320 are executed again;

[0099] S400: Otherwise, the conditions are met and the defrosting procedure is executed.

[0100] In this embodiment, the second additional condition can be determined by judging the attenuation condition of the coil temperature. Of course, this is not restrictive, and other conditions can also be used as the second additional condition.

[0101] To determine the degree of coil temperature attenuation, it is necessary to collect and record the temperature values ​​of the coil at different times, which can be understood as the first coil temperature at the first moment and the second coil temperature at the second moment. The coil temperature attenuation threshold can be 1°C. Of course, other temperature indicators can also be used as reference values. In this embodiment, if the difference between the first coil temperature and the second coil temperature is greater than the coil temperature attenuation threshold, it is considered that the coil temperature decays too quickly and reaches the defrost condition, but a false defrost judgment procedure needs to be performed.

[0102] The present invention further proposes a storage medium, which is suitable for storing a plurality of program codes, wherein the program codes are suitable for being loaded and run by a processor to execute the defrost control method for a heat pump water heater described in any one of the above embodiments.

[0103] In this embodiment, a storage medium is also proposed to store the control method of the above embodiment, which is applied to the corresponding device system in the form of a code program. The storage medium can be a detachable or integrated storage device.

[0104] The present invention also proposes a heat pump water heater, which includes 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 embodiments.

[0105] In the present embodiment, a heat pump water heater is also proposed. By installing a processor to execute a control method set in a storage medium, the heat pump water heater can automatically perform an erroneous defrost program judgment according to the result of the defrost judgment program during operation, thereby more accurately controlling the timing of defrosting and improving user experience. It can also defrost in time to avoid the equipment running under high load and affecting the service life of the heat pump water heater, thereby maximizing the service life of the heat pump water heater for users.

[0106] 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 heat pump water heater comprises a compressor having an exhaust port; the defrost control method comprises the following steps: S1, determining whether to execute a false defrost judgment procedure when the heat pump water heater is running; S2, if the false defrost judgment procedure is executed, obtaining the exhaust port temperature of the compressor; S3, judging whether an exhaust attenuation condition is met based on the exhaust port temperature; S4, if satisfied, execute the defrost procedure; if not satisfied, re-execute steps S1-S3.

2. The defrost control method of a heat pump water heater according to claim 1, characterized in that: The heat pump water heater also includes a water exchange tank; Step S3 further comprises: 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 it is greater, it is not satisfied; otherwise, it is satisfied.

3. The defrost control method of the heat pump water heater according to claim 2, characterized in that: Step S1 further comprises: obtaining the operating time of the compressor when the heat pump water heater is running; Whether to execute the false defrost determination procedure is determined according to the operating time of the compressor.

4. The defrosting control method of the heat pump water heater according to claim 3, characterized in that: The step of "determining whether to execute the error defrost judgment procedure according to the running time of the compressor" is specifically as follows: Determine whether the compressor operating time is greater than the defrost operating time threshold. If so, further determine whether to execute the false defrost judgment procedure based on the first additional condition; if not, continue to obtain the compressor operating time and determine whether it is greater than the defrost operating time threshold.

5. The defrosting control method of the heat pump water heater according to claim 4, characterized in that: The heat pump water heater further includes a coil evaporator, and the coil evaporator exchanges heat with the heat exchange water tank; the step of "further determining whether to execute the error defrosting determination procedure according to the first additional condition" further includes: The coil temperature of the coil evaporator is obtained, and a false defrost determination procedure is selectively performed according to the coil temperature.

6. The defrost control method for a heat pump water heater according to claim 5, characterized in that: The step of "selectively executing the false defrost determination procedure according to the coil temperature" is specifically as follows: Determine whether the coil temperature is less than the defrost coil temperature threshold. If so, execute the false defrost judgment procedure according to the second additional condition; if not, continue to obtain the compressor operation time and determine whether it is greater than the defrost operation time threshold.

7. The defrosting control method of a heat pump water heater according to claim 6, characterized in that: The step of "executing the false defrost determination procedure according to the second additional condition" further includes: It is determined whether the coil temperature satisfies the coil temperature attenuation condition. If so, a false defrost determination procedure is executed; if not, the compressor operation time is continuously obtained and it is determined whether it is greater than a defrost operation time threshold.

8. The defrosting control method of a heat pump water heater according to claim 7, characterized in that: The step of "determining whether the coil temperature satisfies the coil temperature attenuation condition" is specifically as follows: Acquire a first coil temperature of the coil evaporator at a first moment and a second coil temperature at a second moment; It is determined whether the difference between the first coil temperature and the second coil temperature is greater than a coil temperature attenuation threshold; if so, the coil temperature attenuation condition is met, otherwise, it is not met.

9. A storage medium, the storage medium being suitable for storing a plurality of program codes, characterized in that: The program code is suitable for being loaded and run by a processor to execute the defrost control method for a heat pump water heater according to any one of claims 1 to 8.

10. A heat pump water heater, characterized in that: The heat pump 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 8.

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