A control method and control device of an air source heat pump unit and a storage medium

Abstract

The present application relates to the technical field of heat pump unit, and particularly provides a control method and control device of air source heat pump unit and storage medium, aiming at solving the problem of compressor over-range operation and damage to compressor life caused by unit frosting when the heat pump unit operates under high water temperature condition. For this purpose, the control method of air source heat pump unit comprises: in response to the heat pump unit switching to heating mode, obtaining the environment temperature and the coil temperature and outlet water temperature of the finned heat exchanger; in the case of heat pump unit frosting, comparing the outlet water temperature with the first temperature threshold; if the outlet water temperature is greater than or equal to the first temperature threshold, controlling the heat pump unit to defrost according to the corresponding relationship between the environment temperature, the coil temperature and the outlet water temperature. The control method controls the heat pump unit to defrost in time according to the corresponding relationship between the environment temperature, the coil temperature and the outlet water temperature when the heat pump unit is frosted and the outlet water temperature is greater than or equal to the preset value of high water temperature condition.

Description

Technical Field

[0001] This invention relates to the field of heat pump unit technology, specifically providing a control method, control device, and storage medium for an air source heat pump unit. Background Technology

[0002] When an air source heat pump unit is operating in heating mode, the finned heat exchanger is always at a low temperature, and the outdoor temperature is also low. At this time, if the outdoor environment also has high humidity and the coil temperature is below 0°C, the finned heat exchanger fins are prone to frosting. As frosting continues, the heat exchange efficiency of the refrigerant circulation loop will drop sharply, which will lead to a continuous decrease in the heating capacity of the entire heat pump unit.

[0003] Generally, the maximum condensing temperature of a compressor decreases as the evaporating temperature decreases. When an air source heat pump operates at high water temperatures, the compressor's condensing temperature may approach its limit. If the unit frosts, the evaporating temperature will drop, and the unit's condensing temperature may exceed its limit, causing the compressor to operate outside its range and shortening its lifespan.

[0004] Accordingly, there is a need in the field for a new control scheme for air source heat pump units to solve the above problems. Summary of the Invention

[0005] In order to solve the above-mentioned problems in the prior art, namely, to solve the problem that the compressor operates beyond its range and damages its lifespan due to frost formation when the heat pump unit is running under high water temperature conditions, this invention proposes a control method, control device and storage medium for an air source heat pump unit.

[0006] In a first aspect, the present invention provides a control method for an air source heat pump unit, the air source heat pump unit including a finned heat exchanger, the control method comprising:

[0007] In response to the heat pump unit switching to heating mode, the ambient temperature, the coil temperature of the finned heat exchanger, and the outlet water temperature are obtained.

[0008] In the event of frosting of the heat pump unit, the outlet water temperature is compared with a first temperature threshold.

[0009] If the outlet water temperature is greater than or equal to the first temperature threshold, the heat pump unit is controlled to defrost according to the correspondence between ambient temperature, coil temperature and outlet water temperature.

[0010] In one technical solution of the control method for the above-mentioned air source heat pump unit, the frosting of the heat pump unit includes:

[0011] If the ambient temperature is less than the second temperature threshold, and the difference between the ambient temperature and the coil temperature is greater than the first preset threshold, the heat pump unit is determined to be frosting.

[0012] In one technical solution of the control method for the aforementioned air source heat pump unit, the step of controlling the heat pump unit to defrost based on the correspondence between ambient temperature, coil temperature, and outlet water temperature includes:

[0013] Obtain the cumulative heating operation time and continuous heating operation time of the compressor;

[0014] When the cumulative heating operation time of the compressor is greater than the first working time and the continuous heating operation time of the compressor is greater than the second working time, the heat pump unit is controlled to defrost according to the pre-stored correspondence between ambient temperature, coil temperature and outlet water temperature in multiple ambient temperature ranges, wherein the first working time is greater than or equal to the second working time.

[0015] In one technical solution of the control method for the aforementioned air source heat pump unit, the control method further includes:

[0016] When the outlet water temperature is lower than the second temperature threshold, the heat pump unit is controlled to defrost based on the relationship between the ambient temperature and the coil temperature.

[0017] In one technical solution of the control method for the aforementioned air source heat pump unit, the step of controlling the heat pump unit to defrost based on the correspondence between ambient temperature and coil temperature includes:

[0018] Obtain the cumulative heating operation time and continuous heating operation time of the compressor;

[0019] When the cumulative heating operation time of the compressor is greater than the third working time and the continuous heating operation time of the compressor is greater than the fourth working time, the heat pump unit is controlled to defrost according to the pre-stored correspondence between the ambient temperature and the coil temperature in multiple ambient temperature ranges, wherein the third working time is greater than or equal to the fourth working time.

[0020] In one technical solution of the control method for the aforementioned air source heat pump unit, the control method further includes:

[0021] In response to the heat pump unit switching to heating mode, the low-pressure pressure of the compressor is obtained;

[0022] When the heat pump unit is frosted, if the low pressure is less than the second preset threshold, the heat pump unit is controlled to defrost.

[0023] In one technical solution of the control method for the aforementioned air source heat pump unit, the control method further includes:

[0024] Upon the heat pump unit switching to the heating mode, obtain the ambient temperature and the water outlet temperature of the finned heat exchanger;

[0025] When the heat pump unit is not frosting, control the operating state of the heat pump unit according to the corresponding relationship between the ambient temperature and the water outlet temperature.

[0026] In one technical solution of the control method of the above air source heat pump unit, the controlling the operating state of the heat pump unit according to the corresponding relationship between the ambient temperature and the water outlet temperature includes:

[0027] When the relationship between the ambient temperature Ta and the water outlet temperature Tewo satisfies Tewo < a * Ta + b, control the heat pump unit to operate normally;

[0028] When the relationship between the ambient temperature Ta and the water outlet temperature Tewo satisfies Tewo ≥ a * Ta + b, control the heat pump unit to stop;

[0029] After controlling the unit to stop, when the relationship between the ambient temperature Ta and the water outlet temperature Tewo again satisfies Tewo < a * Ta + b - c, control the unit to run again;

[0030] Wherein, a is the first coefficient, b is the first constant, and c is the second constant.

[0031] In a second aspect, the present invention provides a control device, which includes a processor and a storage device. The storage device is adapted to store multiple program codes, and the program codes are adapted to be loaded and run by the processor to execute the method described in any one of the technical solutions of the above control method.

[0032] In a third aspect, there is provided a computer-readable storage medium, which stores multiple program codes therein, and the program codes are adapted to be loaded and run by a processor to execute the method described in any one of the technical solutions of the above control method.

[0033] One or more of the above technical solutions of the present invention have at least one or more of the following beneficial effects:

[0034] In implementing the technical solution of the present invention, a control method, a control device and a storage medium for an air source heat pump unit are proposed. In the heating mode of the heat pump unit, when the heat pump unit is frosting, if the water outlet temperature is greater than or equal to the preset value of the high water temperature condition, according to the corresponding relationship between the ambient temperature, the coil temperature and the water outlet temperature, control the heat pump unit to defrost in time, avoiding the problem that the heat pump unit affects the heating work due to frosting and thus does not meet the heating demand, or avoiding the problem that the heat pump unit forcibly increases the operating range of the compressor to damage the life of the compressor in order to meet the heating demand. Description of the Drawings

[0035] The disclosure of this invention will become more readily understood with reference to the accompanying drawings. It will be readily understood by those skilled in the art that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. Furthermore, similar numbers in the drawings are used to denote similar components, wherein:

[0036] Figure 1 This is a schematic diagram of the main steps of the control method for an air-source heat pump unit under the high water temperature heating condition of a heat pump unit frosting according to an embodiment of the present invention.

[0037] Figure 2 This is a schematic diagram of the main steps of step S103 in an embodiment of the high water temperature heating condition of a heat pump unit frosting according to the present invention.

[0038] Figure 3 This is a schematic diagram of the main steps of the control method for an air-source heat pump unit under the low water temperature heating condition of the heat pump unit frosting according to the present invention.

[0039] Figure 4 This is a schematic diagram of the main steps of step S103' of the low water temperature heating condition of the heat pump unit frosting according to the present invention.

[0040] Figure 5 This is a schematic flowchart of the main steps of a control method for an air-source heat pump unit to control frost formation according to an embodiment of the present invention.

[0041] Figure 6 This is a schematic flowchart of the main steps of a control method for an air-source heat pump unit that prevents frost formation, according to an embodiment of the present invention.

[0042] Figure 7 This is a schematic diagram of the main steps of step S102 of the present invention, which prevents the heat pump unit from frosting.

[0043] Figure 8 This is a schematic diagram of the structure of a control device according to an embodiment of the present invention. Detailed Implementation

[0044] Some embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0045] In the description of this invention, "module" and "processor" can include hardware, software, or a combination of both. A module can include hardware circuitry, various suitable sensors, communication ports, memory, and may also include software components, such as program code, or a combination of software and hardware. A processor can be a central processing unit, microprocessor, image processor, digital signal processor, or any other suitable processor. The processor has data and / or signal processing capabilities. The processor can be implemented in software, in hardware, or a combination of both. Non-transitory computer-readable storage media includes any suitable medium capable of storing program code, such as magnetic disks, hard disks, optical disks, flash memory, read-only memory, random access memory, etc. The term "A and / or B" means all possible combinations of A and B, such as only A, only B, or A and B. The terms "at least one A or B" or "at least one of A and B" have a similar meaning to "A and / or B" and can include only A, only B, or A and B. The singular terms "a" or "this" can also include plural forms.

[0046] Based on the technical problems mentioned in the background art, in order to solve the problem that when a heat pump unit operates at high water temperature, frost formation causes the compressor to exceed its operating range, thereby damaging the compressor's lifespan, this invention provides a control method for an air source heat pump unit. In the heating mode of the heat pump unit, when the heat pump unit frosts, according to a preset value for high water temperature conditions, if the outlet water temperature is greater than or equal to the ambient temperature, the heat pump unit is controlled to defrost in a timely manner based on the correspondence between the ambient temperature, coil temperature, and outlet water temperature. This avoids the heat pump unit from failing to meet heating requirements due to frost formation, or avoids the heat pump unit forcibly increasing the compressor's operating range to meet heating requirements, thereby damaging the compressor's lifespan.

[0047] See appendix Figure 1-7 , Figure 1 This is a schematic flowchart illustrating the main steps of a control method for an air-source heat pump unit according to an embodiment of the present invention. Figure 1 As shown, the control method of the air source heat pump unit in this embodiment of the invention mainly includes the following steps S101-S103.

[0048] Step S101: In response to the heat pump unit switching to heating mode, acquire the ambient temperature, the coil temperature of the finned heat exchanger, and the outlet water temperature.

[0049] Step S102: In the case of frosting of the heat pump unit, the outlet water temperature is compared with a first temperature threshold.

[0050] Step S103: If the outlet water temperature is greater than or equal to the first temperature threshold, the heat pump unit is controlled to defrost according to the correspondence between ambient temperature, coil temperature and outlet water temperature.

[0051] The heat pump unit contains a dedicated heat-absorbing medium, which is a refrigerant. Under low pressure, its evaporation temperature can be lower than the ambient temperature, creating a temperature difference between it and the outside environment. Therefore, the refrigerant absorbs heat energy from the outside, evaporating and vaporizing inside the evaporator. The compressor in the heat pump unit increases the pressure and temperature of the refrigerant, and then the condenser transforms the refrigerant from a gaseous state to a liquid state. During this transformation, a large amount of heat is released and transferred to the stored water in the tank, raising the water temperature to achieve the purpose of producing hot water.

[0052] In one embodiment, the air-side heat exchanger of the air source heat pump unit is a finned heat exchanger when heating. Under heating conditions, the heat pump unit is first judged to be frosted based on the coil temperature, that is, the fins on the finned heat exchanger are judged to be frosted based on the coil temperature.

[0053] In one embodiment, if the ambient temperature is less than a second temperature threshold and the difference between the ambient temperature and the coil temperature is greater than a first preset threshold, the heat pump unit is determined to be frosting.

[0054] In a specific example, when a finned heat exchanger is used as an evaporator, the temperature of the refrigerant inside its heat exchange tubes is called the evaporation temperature. In this embodiment, the coil temperature is equal to the evaporation temperature, and the temperature of the air outside the heat exchange tubes is called the ambient temperature. The difference between the two can be initially considered as the heat transfer temperature difference (i.e., ambient temperature - evaporation temperature, or ambient temperature - coil temperature). The heat transfer temperature difference is related to the design of the heat exchanger and the ambient temperature during the operation of the heat exchanger. In other words, even when the design of a heat exchanger is determined, the heat transfer temperature difference will change with the change of the ambient temperature.

[0055] Of course, even at the same ambient temperature, the heat transfer temperature difference may differ, mainly due to the effect of frost formation on the finned heat exchanger fins. This leads to a deterioration in heat exchanger performance, a decrease in evaporation temperature, and a larger heat transfer temperature difference. For example, when frost forms on the air-side heat exchanger surface to a certain extent: at an ambient temperature of 7°C, the evaporation temperature is -6°C, and the heat transfer temperature difference is 13°C; at an ambient temperature of -12°C, the evaporation temperature is -21°C, and the heat transfer temperature difference is 9°C. To ensure that the heat pump unit's heating capacity still meets the heating requirements even when the finned heat exchanger is frosted, this embodiment of the invention is designed to indicate that when the ambient temperature is below a second temperature threshold, the finned heat exchanger... The heat pump unit may experience frosting. When the ambient temperature is lower than a second temperature threshold and the heat transfer temperature is higher than a first preset threshold, for example, when the second temperature threshold is 0°C and the first preset threshold is 10°C, the heat pump unit is determined to be frosted. In order to better improve the heating capacity of the heat pump unit when the finned heat exchanger is frosted, so that its heating capacity can meet the heating demand, but not by increasing the operating range of the compressor, the air source heat pump unit control method of the present invention is proposed. After determining that the heat pump unit is frosted, the control method controls the timing of defrosting the unit according to the operating conditions of the outlet water temperature.

[0056] In one embodiment, when the heat pump unit is frosted, the outlet water temperature is compared with a first temperature threshold. For example, the first temperature threshold is 50°C. When the outlet water temperature is greater than or equal to 50°C, it indicates that the current heating condition is a high water temperature heating condition. When the outlet water temperature is less than 50°C, it indicates that the current heating condition is a low water temperature heating condition. Under the high water temperature heating condition, the heat pump unit is controlled to defrost based on the correspondence between the ambient temperature, the coil temperature, and the outlet water temperature. Under the low water temperature heating condition, the heat pump unit is controlled to defrost based on the correspondence between the ambient temperature and the coil temperature.

[0057] In one implementation, under high water temperature heating conditions, i.e. when the outlet water temperature is greater than or equal to a first temperature threshold, the heat pump unit is controlled to defrost based on the correspondence between ambient temperature, coil temperature and outlet water temperature.

[0058] In one implementation, Figure 2 This is a schematic flowchart of the main steps in step S103 of an embodiment of the high water temperature heating condition of a heat pump unit frosting according to the present invention. Figure 2 As shown, if the outlet water temperature is greater than or equal to the first temperature threshold, the heat pump unit is controlled to defrost based on the correspondence between ambient temperature, coil temperature, and outlet water temperature, including:

[0059] Step S1031: Obtain the cumulative heating operation time t1 and the continuous heating operation time t2 of the compressor.

[0060] In one implementation, under high water temperature heating conditions, for example, the cumulative heating operation time t1 of the compressor is obtained as 12 minutes, and the continuous heating operation time t2 of the compressor is obtained as 6 minutes.

[0061] Step S1032: When the cumulative heating operation time t1 of the compressor is greater than the first working time and the continuous heating operation time t2 of the compressor is greater than the second working time, the heat pump unit is controlled to defrost according to the pre-stored correspondence between ambient temperature, coil temperature and outlet water temperature in multiple ambient temperature ranges, wherein the first working time is greater than or equal to the second working time.

[0062] Continuing with the above implementation method, assuming the first working time is 10 minutes and the second working time is 5 minutes, the current high water temperature heating condition t1 is 12 minutes, which is greater than the first working time of 10 minutes, and the compressor's continuous heating operation time t2 is 6 minutes, which is greater than the second working time of 5 minutes, the condition for controlling the heat pump unit to defrost is satisfied according to the pre-stored correspondence between ambient temperature, coil temperature and outlet water temperature in multiple ambient temperature ranges. Then the following relationship is satisfied, and the heat pump unit is controlled to perform defrosting.

[0063] Ta>Ta1, Te≤d1*Ta+e1*Tewo+f1;

[0064] Ta2 <Ta≤Ta1,Te≤d2*Ta+e2*Tewo+f2;

[0065] Ta3<Ta≤Ta2, Te≤d3*Ta+e3*Tewo+f3;

[0066] Ta4<Ta≤Ta3, Te≤d4*Ta+e4*Tewo+f4;

[0067] Ta<Ta4, Te≤d5*Ta+e5*Tewo+f5;

[0068] Where Ta is the ambient temperature, Te is the coil temperature, Tewo is the outlet water temperature, and Ta1, Ta2, Ta3, and Ta4 are the first, second, third, and fourth preset ambient temperatures, respectively, with Ta1 > Ta2 > Ta3 > Ta4. The ambient temperature is divided into several different ambient temperature ranges, for example, Ta1 is 10℃, Ta2 is 0℃, Ta3 is -5℃, Ta4 is -15℃, and d1, d2, d3, d4, d5, ... e1, e2, e3, e4, e5, f1, f2, f3, f4, and f5 are constants because the higher the value of Tewo, the higher the value of Te condition is met, and the easier it is for the heat pump unit to enter defrost mode. Therefore, e1, e2, e3, e4, and e5 are positive values. The specific values ​​of d1, d2, d3, d4, d5, e1, e2, e3, e4, e5, f1, f2, f3, f4, and f5 are obtained by fitting the relationship between ambient temperature, coil temperature, and outlet water temperature when testing the defrost entry conditions.

[0069] It should be noted that, in order to make the defrosting determination more accurate, defrosting can be performed after the relationship is satisfied for a period of time, such as 2 minutes.

[0070] In one implementation, Figure 3 This is a schematic flowchart illustrating the main steps of the control method for an air-source heat pump unit under low water temperature heating conditions with frosting, according to the present invention. Figure 3 As shown, the control method further includes:

[0071] Step S103': If the outlet water temperature is lower than the first temperature threshold, control the heat pump unit to defrost according to the correspondence between ambient temperature and coil temperature.

[0072] In one implementation, Figure 4 This is a schematic flowchart illustrating the main steps of step S103' in the low-temperature heating condition of a heat pump unit frosting according to the present invention. Figure 4 As shown, under low water temperature heating conditions, i.e., when the outlet water temperature is lower than the first temperature threshold, the heat pump unit is controlled to defrost based on the relationship between ambient temperature and coil temperature, including:

[0073] Step S1031': Obtain the cumulative heating operation time t3 and the continuous heating operation time t4 of the compressor.

[0074] In one implementation, under low water temperature heating conditions, for example, the cumulative heating operation time t3 of the compressor is obtained as 16 minutes, and the continuous heating operation time t4 of the compressor is obtained as 6 minutes.

[0075] Step S1032': When the cumulative heating operation time t3 of the compressor is greater than the third working time and the continuous heating operation time t4 of the compressor is greater than the fourth working time, the heat pump unit is controlled to defrost according to the pre-stored correspondence between ambient temperature and coil temperature in multiple ambient temperature ranges, wherein the third working time is greater than or equal to the fourth working time.

[0076] It should be noted that the first working time is shorter than the third working time because the cumulative heating operation time of the compressor under high water temperature heating conditions can be shorter than the cumulative heating operation time of the compressor under low water temperature heating conditions when determining whether the defrosting conditions are met. The second and fourth working times are not specifically defined and can be equal or unequal.

[0077] Continuing with the above implementation method, assuming the third working time is 12 minutes and the second working time is still 5 minutes, the current high water temperature heating condition t3 is 16 minutes, which is greater than the third working time of 12 minutes, and the compressor's continuous heating operation time t4 is 6 minutes, which is greater than the fourth working time of 5 minutes. This satisfies the condition of controlling the heat pump unit to defrost based on the pre-stored correspondence between ambient temperature and coil temperature in multiple ambient temperature ranges. Therefore, the following relationship is satisfied, and the heat pump unit is controlled to perform defrosting.

[0078] Ta>Ta1, Te≤a1*Ta-b1;

[0079] Ta2 <Ta≤Ta1,Te≤a2*Ta-b2;

[0080] Ta3 <Ta≤Ta2,Te≤a3*Ta-b3;

[0081] Ta4 <Ta≤Ta3,Te≤a4*Ta-b4;

[0082] Ta <Ta4,Te≤a5*Ta-b5;

[0083] Where Ta is the ambient temperature, Te is the coil temperature, and Ta1, Ta2, Ta3, and Ta4 are the first, second, third, and fourth preset ambient temperatures, respectively, with Ta1 > Ta2 > Ta3 > Ta4. The ambient temperature is divided into several different ambient temperature ranges, for example, Ta1 is 10℃, Ta2 is 0℃, Ta3 is -5℃, and Ta4 is -15℃. a1, a2, a3, a4, a5, b1, b2, b3, b4, and b5 are constants. The specific values ​​of a1, a2, a3, a4, a5, b1, b2, b3, b4, and b5 are obtained by fitting the relationship between the ambient temperature and the coil temperature when the defrosting condition is met.

[0084] It should be noted that, in order to make the defrosting determination more accurate, defrosting can be performed after the relationship is satisfied for a period of time, such as 2 minutes.

[0085] In one implementation, Figure 5 This is a schematic flowchart illustrating the main steps of a control method for an air-source heat pump unit based on an embodiment of the present invention regarding frosting. Figure 5 As shown, the control method further includes:

[0086] Step S101': In response to the heat pump unit switching to heating mode, obtain the low-pressure pressure of the compressor;

[0087] Step S102': When the heat pump unit is frosted, if the low pressure is less than the second preset threshold, control the heat pump unit to defrost.

[0088] It should be noted that, at this time, whether the heat pump unit is in high water temperature heating mode or low water temperature heating mode, as long as the low pressure of the compressor is less than the minimum allowable operating pressure of the compressor, the heat pump unit will be immediately controlled to defrost. The second preset threshold is determined according to the minimum allowable operating pressure of the compressor.

[0089] In one implementation, Figure 6 This is a schematic flowchart illustrating the main steps of a control method for an air-source heat pump unit according to an embodiment of the present invention, which prevents frost formation in the heat pump unit. Figure 6 As shown, the control method further includes:

[0090] Step S101”: In response to the heat pump unit switching to heating mode, obtain the ambient temperature and the outlet water temperature of the finned heat exchanger;

[0091] Step S102”: When the heat pump unit does not frost, control the operating status of the heat pump unit according to the correspondence between the ambient temperature and the outlet water temperature.

[0092] In one embodiment, when the ambient temperature is greater than or equal to a second temperature threshold, for example, when the second temperature threshold is 10°C, the fins of the finned heat exchanger will never frost over. When the heat pump unit does not frost over, the operating status of the heat pump unit is controlled according to the correspondence between the outlet water temperature of the finned heat exchanger and the ambient temperature.

[0093] In one implementation, Figure 7 This is a schematic flowchart of the main steps in step S102 of the present invention, which prevents the heat pump unit from frosting. Figure 7 As shown, controlling the operating status of the heat pump unit based on the correspondence between ambient temperature and outlet water temperature includes:

[0094] Step S1021”: When the relationship between the ambient temperature Ta and the outlet water temperature Tewo satisfies Tewo < a * Ta + b, control the heat pump unit to operate normally;

[0095] Step S1022”: When the relationship between the ambient temperature Ta and the outlet water temperature Tewo satisfies Tewo ≥ a * Ta + b, control the heat pump unit to stop;

[0096] Step S1023”: After the control unit stops, when the relationship between the ambient temperature Ta and the outlet water temperature Tewo satisfies Tewo < a * Ta + b - c again, control the unit to run again;

[0097] Where, a is the first coefficient, b is the first constant, and c is the second constant.

[0098] In a specific example, when the ambient temperature Ta is 0°C, the refrigerant of the finned heat exchanger absorbs heat from the ambient air and evaporates and vaporizes inside the evaporator. Its corresponding evaporation temperature is -5°C. The temperature of the refrigerant is increased by the operation of the compressor in the heat pump unit. At this time, the evaporation temperature of -5°C corresponds to a maximum condensation temperature of 65°C. Then, the refrigerant is converted from a vapor state to a liquid state through the condenser, and a large amount of heat is released during the conversion process. At this time, the maximum condensation temperature of 65°C corresponds to a maximum outlet water temperature Tewo of 60°C.

[0099] Substitute the ambient temperature Ta of 0°C and the outlet water temperature Tewo of 60°C into the relational expression of the ambient temperature and the outlet water temperature. When Tewo < a * Ta + b, control the heat pump unit to operate normally; when Tewo ≥ a * Ta + b, control the heat pump unit to stop; after the unit stops for a period of time, since the unit no longer generates heating capacity, the outlet water temperature slowly decreases based on 60°C as time goes by. For example, when the value of c is 15, when the outlet water temperature value drops from 60°C to below 45°C after a period of time, control the heat pump unit to run again and heat again to heat the outlet water temperature to 60°C.

[0100] Based on the above Steps S101 - S103, the present invention proposes a control method, a control device and a storage medium for an air source heat pump unit. In the heating mode of the heat pump unit, when the heat pump unit frosts, if the outlet water temperature is greater than or equal to the preset value of the high water temperature condition, according to the corresponding relationship between the ambient temperature, the coil temperature and the outlet water temperature, control the heat pump unit to defrost in time, so as to avoid the problem that the heat pump unit affects the heating work due to frosting and thus does not meet the heating demand, or avoid the problem that the heat pump unit forcibly increases the operation range of the compressor to damage the life of the compressor in order to meet the heating demand.

[0101] It should be noted that although the steps in the above embodiments are described in a specific order, those skilled in the art will understand that in order to achieve the effects of the present invention, different steps do not necessarily have to be executed in such an order. They can be executed simultaneously (in parallel) or in other orders, and these variations are all within the scope of protection of the present invention.

[0102] Those skilled in the art will understand that all or part of the processes in the method of the above embodiment of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or some intermediate form. The computer-readable storage medium can include any entity or device capable of carrying the computer program code, a medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory, a random access memory, an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc. It should be noted that the content included in the computer-readable storage medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable storage medium does not include electrical carrier signals and telecommunication signals.

[0103] Furthermore, the present invention also provides a control device. For example... Figure 8 As shown, in one embodiment of the control device according to the present invention, the control device includes a processor and a storage device. The storage device can be configured to store a program for executing the control method of the above-described method embodiments, and the processor can be configured to execute the program in the storage device. This program includes, but is not limited to, a program for executing the control method of the above-described method embodiments. For ease of explanation, only the parts related to the embodiments of the present invention are shown; for specific technical details not disclosed, please refer to the method section of the embodiments of the present invention. This control device can be a control device device comprising various electronic devices.

[0104] Furthermore, the present invention also provides a computer-readable storage medium. In one embodiment of the computer-readable storage medium according to the present invention, the computer-readable storage medium can be configured to store a program that performs the control method of the above-described method embodiments, the program being loaded and run by a processor to implement the above-described control method. For ease of explanation, only the parts related to the embodiments of the present invention are shown; for specific technical details not disclosed, please refer to the method section of the embodiments of the present invention. The computer-readable storage medium can be a storage device comprising various electronic devices. Optionally, in the embodiments of the present invention, the computer-readable storage medium is a non-transitory computer-readable storage medium.

[0105] Furthermore, it should be understood that since the various modules are only provided to illustrate the functional units of the device of the present invention, the physical devices corresponding to these modules may be the processor itself, or a part of the processor's software, hardware, or a combination of software and hardware. Therefore, the number of modules shown in the figures is merely illustrative.

[0106] Those skilled in the art will understand that the various modules in the device can be adaptively split or combined. Such splitting or combining of specific modules will not cause the technical solution to deviate from the principles of the present invention; therefore, the technical solutions after splitting or combining will fall within the protection scope of the present invention.

[0107] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles 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 such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A control method for an air source heat pump unit, wherein the air source heat pump unit includes a finned heat exchanger, characterized in that, The control method includes: In response to the heat pump unit switching to the heating mode, obtaining the ambient temperature, the coil temperature, and the outlet water temperature of the finned heat exchanger; When the heat pump unit is frosting, comparing the outlet water temperature with a first temperature threshold; If the outlet water temperature is greater than or equal to the first temperature threshold, controlling the heat pump unit to defrost according to the corresponding relationship among the ambient temperature, the coil temperature, and the outlet water temperature; The controlling the heat pump unit to defrost according to the corresponding relationship among the ambient temperature, the coil temperature, and the outlet water temperature includes: obtaining the cumulative heating operation time and the continuous heating operation time of the compressor; when the cumulative heating operation time of the compressor is greater than a first working duration and the continuous heating operation time of the compressor is greater than a second working duration, controlling the heat pump unit to defrost according to the corresponding relationship formulas among the ambient temperature, the coil temperature, and the outlet water temperature within multiple pre-stored ambient temperature ranges, where the first working duration is greater than or equal to the second working duration; The corresponding relationship formulas among the ambient temperature, the coil temperature, and the outlet water temperature include: Ta>Ta1, Te≤d1*Ta+e1*Tewo+f1; Ta_2<Ta≤Ta1, Te≤d2*Ta+e2*Tewo+f2; Ta_3<Ta≤Ta_2, Te≤d3*Ta+e3*Tewo+f3; Ta_4<Ta≤Ta_3, Te≤d4*Ta+e4*Tewo+f4; Ta<Ta_4, Te≤d5*Ta+e5*Tewo+f5; where Ta is the ambient temperature, Te is the coil temperature, Tewo is the outlet water temperature, Ta1, Ta2, Ta3, and Ta4 are the first preset ambient temperature, the second preset ambient temperature, the third preset ambient temperature, and the fourth preset ambient temperature respectively, and d1, d2, d3, d4, d5, e1, e2, e3, e4, e5, f1, f2, f3, f4, and f5 are constants.

2. The control method according to claim 1, characterized in that, The frosting of the heat pump unit includes: If the ambient temperature is less than a second temperature threshold and the difference between the ambient temperature and the coil temperature is greater than a first preset threshold, it is determined that the heat pump unit is frosting.

3. The control method according to claim 1, characterized in that, The control method further includes: When the outlet water temperature is less than the second temperature threshold, controlling the heat pump unit to defrost according to the corresponding relationship between the ambient temperature and the coil temperature.

4. The control method according to claim 3, characterized in that, The controlling the heat pump unit to defrost according to the corresponding relationship between the ambient temperature and the coil temperature includes: Obtaining the cumulative heating operation time and the continuous heating operation time of the compressor; When the cumulative heating operation time of the compressor is greater than a third working duration and the continuous heating operation time of the compressor is greater than a fourth working duration, controlling the heat pump unit to defrost according to the corresponding relationship formulas between the ambient temperature and the coil temperature within multiple pre-stored ambient temperature ranges, where the third working duration is greater than or equal to the fourth working duration.

5. The control method according to claim 1, characterized in that, The control method further includes: In response to the heat pump unit switching to the heating mode, obtaining the low pressure of the compressor; When the heat pump unit is frosting and the low pressure is less than a second preset threshold, controlling the heat pump unit to defrost.

6. The control method according to claim 1, characterized in that, The control method further includes: In response to the heat pump unit switching to the heating mode, obtain the ambient temperature and the water outlet temperature of the finned heat exchanger; When the heat pump unit is not frosting, control the operating state of the heat pump unit according to the corresponding relationship between the ambient temperature and the water outlet temperature.

7. The control method according to claim 6, characterized in that, The controlling the operating state of the heat pump unit according to the corresponding relationship between the ambient temperature and the water outlet temperature includes: When the relationship between the ambient temperature Ta and the water outlet temperature Tewo satisfies Tewo < a*Ta + b, control the heat pump unit to operate normally; When the relationship between the ambient temperature Ta and the water outlet temperature Tewo satisfies Tewo ≥ a*Ta + b, control the heat pump unit to stop; After controlling the heat pump unit to stop, when the relationship between the ambient temperature Ta and the water outlet temperature Tewo again satisfies Tewo < a*Ta + b - c, control the unit to restart; Where, a is the first coefficient, b is the first constant, and c is the second constant.

8. A control device, comprising a processor and a storage device, said storage device being adapted to store a plurality of program codes, characterized in that, The program code is adapted to be loaded and run by the processor to execute the control method according to any one of claims 1 to 7.

9. A computer-readable storage medium storing a plurality of program codes, characterized in that, The program code is adapted to be loaded and run by the processor to execute the control method according to any one of claims 1 to 7.

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