Defrost mode triggering method, device, air conditioner and readable storage medium

Abstract

The present invention proposes a defrost mode triggering method, device, air conditioner and readable storage medium, the method comprising the following steps: if the heating mode is triggered, the outdoor unit coil temperature and the outdoor ambient temperature are continuously monitored; the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature is calculated; the change trend of the temperature difference change rate is obtained, and whether the heating mode has reached a stable operation stage is judged according to the change trend of the temperature difference change rate; if the heating mode has reached a stable operation stage, whether the outdoor heat exchanger meets the defrost condition is judged according to the change trend of the temperature difference change rate; if the outdoor heat exchanger meets the defrost condition, the defrost mode is switched. By determining the change trend of the outdoor unit coil temperature, the frosting condition of the outdoor heat exchanger can be reflected by the temperature change rate, thereby ensuring the matching of the defrost mode triggering and the frosting condition of the outdoor heat exchanger.

Description

Technical Field

[0001] The present invention relates to the field of air conditioners, and in particular to a defrost mode triggering method, device, air conditioner and readable storage medium. Background Art

[0002] When the air-cooled heat pump commercial air conditioner is running in winter, the outdoor heat exchanger will be frosted, resulting in a decrease in heat exchange capacity, so defrosting is required. In the prior art, the running time is used to judge whether the outdoor heat exchanger is frosted, and the defrost mode is triggered when it is considered to be frosted; however, based on the different specific application scenarios of the air conditioner, such as areas with high humidity, it is more likely to frost, while areas with low humidity are not easy to frost. The judgment based on the fixed running time in the prior art often does not match the actual frosting situation of the outdoor heat exchanger. In this case, triggering the defrost mode will generate unnecessary energy consumption and affect the normal use of the air conditioner. Summary of the invention

[0003] The main purpose of the present invention is to propose a defrost mode triggering method, device, air conditioner and readable storage medium, aiming to solve the problem in the prior art that the triggering of the defrost mode does not match the frosting condition of the outdoor heat exchanger.

[0004] To achieve the above object, the present invention provides a defrost mode triggering method, the method comprising the steps of:

[0005] If the heating mode is triggered, the outdoor unit coil temperature and outdoor ambient temperature are continuously monitored;

[0006] Calculating the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature;

[0007] Determining a temperature difference change rate of the temperature difference based on the continuously detected temperature difference, obtaining a change trend of the temperature difference change rate, and judging whether the heating mode has reached a stable operation stage according to the change trend of the temperature difference change rate;

[0008] If the heating mode reaches a stable operation stage, judging whether the outdoor heat exchanger meets the defrosting condition according to the change trend of the temperature difference change rate;

[0009] If the outdoor heat exchanger meets the defrosting condition, it switches to the defrosting mode.

[0010] Optionally, judging whether the heating mode has reached a stable operation stage according to the change trend of the temperature difference change rate includes:

[0011] After the heating mode is triggered, determining whether the temperature difference change rate continues to increase;

[0012] If the temperature difference change rate continues to increase, determining whether the temperature difference change rate is monitored to be 0;

[0013] If it is monitored that the temperature difference change rate is 0, it is determined that the heating mode has reached a stable operation stage.

[0014] Optionally, judging whether the outdoor heat exchanger meets the defrosting condition according to the change trend of the temperature difference change rate includes:

[0015] Determining whether the temperature difference change rate continues to increase;

[0016] If the temperature difference change rate continues to increase, determining whether the temperature difference change rate is monitored to be 0;

[0017] If it is monitored that the temperature difference change rate is 0, it is determined that the outdoor heat exchanger meets the defrosting condition.

[0018] Optionally, judging whether the outdoor heat exchanger meets the defrosting condition according to the temperature difference change rate includes:

[0019] Obtaining a preset duration threshold and a heating operation duration of the heating mode;

[0020] Determine whether the heating operation time is greater than the preset time threshold;

[0021] If the heating operation time is greater than the preset time threshold, it is determined whether the outdoor heat exchanger meets the defrosting condition according to the change trend of the temperature difference change rate.

[0022] Optionally, judging whether the outdoor heat exchanger meets the defrosting condition according to the temperature difference change rate includes:

[0023] Determine a target temperature difference threshold, and determine whether the temperature difference is greater than or equal to the target temperature difference threshold;

[0024] If the temperature difference is greater than or equal to the target temperature difference threshold, it is determined whether the outdoor heat exchanger meets the defrosting condition according to the change trend of the temperature difference change rate.

[0025] Optionally, determining the target temperature difference threshold comprises:

[0026] Acquire the outdoor ambient temperature and a preset ambient temperature range, and determine whether the outdoor ambient temperature is within the preset ambient temperature range;

[0027] If the outdoor ambient temperature is greater than the maximum value of the preset ambient temperature range, determining the target temperature difference threshold to be the first temperature difference threshold;

[0028] If the outdoor ambient temperature is within the preset ambient temperature range, determining the target temperature difference threshold to be a second temperature difference threshold, wherein the second temperature difference threshold is less than the first temperature difference threshold;

[0029] If the outdoor ambient temperature is lower than the minimum value of the preset ambient temperature range, the target temperature difference threshold is determined to be a third temperature difference threshold, wherein the third temperature difference threshold is lower than the second temperature difference threshold.

[0030] In order to achieve the above object, the present invention further provides a defrost mode triggering device, the defrost mode triggering device comprising:

[0031] The first monitoring module is used to continuously monitor the outdoor unit coil temperature and the outdoor ambient temperature if the heating mode is triggered;

[0032] A first calculation module, used for calculating the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature;

[0033] A first judgment module is used to determine the temperature difference change rate of the temperature difference based on the continuously detected temperature difference, obtain the change trend of the temperature difference change rate, and judge whether the heating mode reaches a stable operation stage according to the change trend of the temperature difference change rate;

[0034] A second judgment module is used to judge whether the outdoor heat exchanger meets the defrosting condition according to the change trend of the temperature difference change rate if the heating mode reaches the stable operation stage;

[0035] The first switching module is used to switch to the defrost mode if the outdoor heat exchanger meets the defrost condition.

[0036] To achieve the above objectives, the present invention also provides an air conditioner, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program implements the steps of the defrost mode triggering method as described above when executed by the processor.

[0037] To achieve the above object, the present invention further provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the defrost mode triggering method as described above are implemented.

[0038] The present invention proposes a defrost mode triggering method, device, air conditioner and readable storage medium. If the heating mode is triggered, the outdoor unit coil temperature and the outdoor ambient temperature are continuously monitored; the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature is calculated; the temperature difference change rate of the temperature difference is determined based on the continuously detected temperature difference, the change trend of the temperature difference change rate is obtained, and whether the heating mode has reached a stable operation stage is judged according to the change trend of the temperature difference change rate; if the heating mode has reached a stable operation stage, whether the outdoor heat exchanger meets the defrost condition is judged according to the change trend of the temperature difference change rate; if the outdoor heat exchanger meets the defrost condition, it is switched to the defrost mode. By monitoring the temperature change rate of the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature, the changing trend of the outdoor unit coil temperature can be determined. The change of the outdoor unit coil temperature is affected by its frosting condition. Therefore, the temperature change rate can reflect the frosting condition of the outdoor heat exchanger, and then based on the temperature change rate, it can be accurately determined whether the outdoor heat exchanger needs to be defrosted, ensuring the match between the defrost mode trigger and the frosting condition of the outdoor heat exchanger, avoiding unnecessary energy consumption, and avoiding affecting the normal operation of the air conditioner. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0041] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0042] Figure 1 It is a flow chart of the first embodiment of the defrost mode triggering method of the present invention;

[0043] Figure 2 It is a schematic diagram of the outdoor unit coil temperature and the outdoor ambient temperature in the defrost mode triggering method of the present invention;

[0044] Figure 3 It is a schematic diagram of the temperature difference change rate in the defrost mode triggering method of the present invention;

[0045] Figure 4 It is a schematic diagram of the module structure of the air conditioner of the present invention. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0047] The disclosure below provides many different embodiments or examples to implement different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed.

[0048] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only embodiments of a part of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work should fall within the scope of protection of the present application.

[0049] The present invention provides a defrost mode triggering method, referring to Figure 1 , Figure 1 This is a flow chart of a first embodiment of a defrost mode triggering method of the present invention, the method comprising the steps of:

[0050] Step S10, if the heating mode is triggered, the outdoor unit coil temperature and the outdoor ambient temperature are continuously monitored;

[0051] It can be understood that, in the cooling mode, the indoor unit acts as an evaporator and the outdoor unit acts as a condenser. At this time, the temperature of the outdoor heat exchanger is increased, so there is no problem of frosting of the outdoor heat exchanger due to the cooling mode; while in the heating mode, the indoor unit acts as a condenser and the outdoor unit acts as an evaporator. At this time, the temperature of the outdoor heat exchanger is reduced, so there may be a problem of frosting of the outdoor heat exchanger due to the heating mode; therefore, in this embodiment, the operation of the heating mode is used as a trigger for determining whether the outdoor heat exchanger is frosted.

[0052] The outdoor unit coil temperature is affected by the outdoor unit evaporation conditions. It is understandable that the corresponding evaporation conditions are different when the outdoor heat exchanger is frosted or not. For example, when the outdoor heat exchanger is frosted, the thermal resistance of the outdoor heat exchanger will increase and the heat exchange rate will decrease, thereby causing the outdoor unit coil temperature to drop.

[0053] The outdoor unit coil temperature and the outdoor ambient temperature can be monitored by setting specific temperature detection devices based on actual needs.

[0054] Step S20, calculating the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature;

[0055] The temperature difference is the difference between the outdoor unit coil temperature and the outdoor ambient temperature. It is understandable that when the air conditioner is not started, since the outdoor unit is set in the outdoor environment, the outdoor unit coil temperature is generally the same as the outdoor ambient temperature. After the air conditioner is started and the heating mode is triggered, the outdoor unit determines that the pipe temperature gradually decreases, while the outdoor ambient temperature remains roughly the same. Therefore, in the heating mode, the outdoor unit coil temperature will be lower than the outdoor ambient temperature; therefore, the temperature difference in this embodiment can be set to the value of the outdoor ambient temperature-the outdoor unit coil temperature, thereby obtaining a positive temperature difference. It is understandable that the temperature difference can also be set to the value of the outdoor unit coil temperature-the outdoor ambient temperature, thereby obtaining a negative temperature difference; in this embodiment, the temperature difference is taken as an example for explanation, and the negative value can be set by analogy, and will not be repeated.

[0056] Step S30, determining a temperature difference change rate of the temperature difference based on the continuously detected temperature difference, obtaining a change trend of the temperature difference change rate, and judging whether the heating mode has reached a stable operation stage according to the change trend of the temperature difference change rate;

[0057] The temperature difference change rate is used to indicate the change of the temperature difference; it can be understood that the faster the temperature difference changes, the faster the difference between the outdoor unit coil temperature and the outdoor ambient temperature changes, the faster the outdoor unit coil temperature changes, and the faster the change of the evaporation condition of the outdoor unit. Specifically, the temperature difference change rate can be expressed as the slope of the temperature difference. On the curve of the temperature difference changing over time, the greater the slope of the point where the temperature difference is located, the greater the corresponding temperature difference change rate, and the smaller the slope of the point where the temperature difference is located, the smaller the corresponding temperature difference change rate.

[0058] The temperature difference change rate reflects the change in the evaporation condition of the outdoor unit, and the evaporation condition of the outdoor unit is affected by the frost on the outdoor heat exchanger. Therefore, the temperature difference change rate can reflect whether the outdoor heat exchanger is frosted; the defrost condition indicates whether the outdoor heat exchanger is frosted, or whether the degree of frost has reached the level that requires defrosting.

[0059] Step S40, if the heating mode reaches a stable operation stage, judging whether the outdoor heat exchanger meets the defrosting condition according to the change trend of the temperature difference change rate;

[0060] See also Figure 2 In heating mode, the heat pump unit generally goes through the initial operation stage, stable operation stage, frosting stage and frosting completion stage. The outdoor unit coil temperature is different in different stages, so the corresponding temperature difference change rate has different changing trends.

[0061] The initial stage of triggering the heating mode is the initial operation stage. In the initial operation stage, the outdoor unit coil temperature drops rapidly to achieve heating as soon as possible. After that, the outdoor unit coil temperature increases slightly and finally reaches stability and enters the stable operation stage. It can be understood that the duration of the initial operation stage is very short, and generally it will soon enter the stable operation stage.

[0062] In the stable operation stage, the outdoor unit coil temperature remains basically stable. If the outdoor environment does not reach the frosting condition, that is, the outdoor heat exchanger is not frosted, it will remain in the stable operation stage. If the outdoor environment reaches the frosting condition, that is, the outdoor heat exchanger begins to frost, it will enter the frosting stage.

[0063] In the frosting stage, the thermal resistance of the outdoor heat exchanger increases and the heat exchange rate decreases. Therefore, the temperature of the outdoor unit coil continues to drop. As the frosting area increases, the thermal resistance further increases, the heat exchange rate further decreases, and the temperature of the outdoor unit coil further drops. When the outdoor heat exchanger is completely frosted, the temperature drop of the outdoor unit coil slows down and finally stabilizes at a lower temperature value, entering the frosting completion stage.

[0064] During the frosting completion stage, the outdoor unit coil temperature will be stably maintained at a lower temperature value.

[0065] The above stages are described based on the outdoor unit coil temperature. As can be seen from the above description, there is a corresponding relationship between the outdoor unit coil temperature, the temperature difference, and the temperature difference change rate. Therefore, the change trend of the temperature change rate can be determined based on the outdoor unit coil temperature.

[0066] As can be seen from the above description, in the heating mode, the stable operation period will be entered quickly. At the same time, in the stable operation period, whether to enter the frosting period will be determined based on the frosting condition of the outdoor heat exchanger, that is, the stable operation period will be entered before the outdoor heat exchanger frosts. Therefore, in this embodiment, the stable operation period is determined, and after determining to enter the stable operation period, it is judged whether the outdoor heat exchanger is frosted and whether the defrosting conditions are met, so that the state of the outdoor heat exchanger can be accurately determined. Step S50, if the outdoor heat exchanger meets the defrosting conditions, switch to the defrosting mode.

[0067] When the temperature difference change rate meets the defrost condition, it is considered that the outdoor heat exchanger meets the defrost condition and needs to be defrosted, so it switches to the defrost mode. When the temperature difference change rate does not meet the defrost condition, the heating mode is maintained.

[0068] This embodiment monitors the temperature change rate of the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature, so that the change trend of the outdoor unit coil temperature can be determined. The change of the outdoor unit coil temperature is affected by its frosting condition. Therefore, the temperature change rate can reflect the frosting condition of the outdoor heat exchanger, and then based on the temperature change rate, it can be accurately determined whether the outdoor heat exchanger needs to be defrosted, thereby ensuring the matching of the defrost mode triggering and the frosting condition of the outdoor heat exchanger, avoiding unnecessary energy consumption, and avoiding affecting the normal operation of the air conditioner.

[0069] Further, in the second embodiment of the defrost mode triggering method of the present invention proposed based on the first embodiment of the present invention, the step S30 includes the steps of:

[0070] Step S31, after the heating mode is triggered, determining whether the temperature difference change rate continues to increase;

[0071] Step S32, if the temperature difference change rate continues to increase, determine whether the temperature difference change rate is monitored to be 0;

[0072] Step S33: if it is monitored that the temperature difference change rate is 0, it is determined that the heating mode has reached a stable operation stage.

[0073] See also Figure 3 In the initial operation stage, the outdoor unit coil temperature drops rapidly to achieve heating as soon as possible. As the outdoor unit coil temperature drops, the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature increases rapidly. Therefore, the temperature difference change rate continues to increase. After that, the outdoor unit coil temperature increases slightly, and the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature decreases slightly. After that, the outdoor unit coil temperature tends to stabilize. When the outdoor unit coil temperature is stable, the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature remains unchanged, and the temperature difference change rate is 0. Entering the stable operation stage.

[0074] It should be noted that in actual applications, due to issues such as device accuracy and system fluctuations, even in the stable operation stage, the outdoor unit coil temperature may not remain completely fixed, but fluctuate within a small range and be dynamically stable. Therefore, when determining whether the heating mode has reached the stable operation stage, a tolerance threshold can be set. When the absolute value of the temperature difference change rate is less than the tolerance threshold, it is considered that the outdoor unit coil temperature is stable and the heating mode has reached the stable operation stage. The same setting can be made later when it is determined that the temperature difference change rate is 0, which will not be repeated.

[0075] It should be noted that in the initial operation stage, the outdoor unit coil temperature has a tendency to first decrease and then increase. During the switching process between decrease and increase, the temperature difference change rate may be detected to be 0, but this is still the initial operation stage. In order to avoid this problem, after the temperature difference change rate continues to increase, the decreasing stage of the temperature difference change rate may be detected. After the decreasing stage of the temperature difference change rate is detected, if the temperature difference change rate is detected to be 0, it is determined that the heating mode has reached the stable operation stage; or a duration threshold is set. After the temperature difference change rate continues to increase, if the temperature difference change rate is detected to be 0 and the duration reaches the duration threshold, it is determined that the heating mode has reached the stable operation stage.

[0076] Furthermore, the step S40 includes the steps of:

[0077] Step S41, determining whether the temperature difference change rate continues to increase;

[0078] Step S42, if the temperature difference change rate continues to increase, determine whether the temperature difference change rate is monitored to be 0;

[0079] If the temperature difference change rate does not continue to increase, the outdoor heat exchanger does not meet the defrosting condition;

[0080] Step S43: If it is detected that the temperature difference change rate is 0, it is determined that the outdoor heat exchanger meets the defrosting condition.

[0081] In the stable operation stage, the outdoor unit coil temperature remains basically stable, so the temperature difference will remain stable and the temperature difference change rate will remain at 0; if the outdoor environment does not reach the frosting condition, that is, the outdoor heat exchanger is not frosted, it will remain in the stable operation stage, that is, the temperature difference change rate will remain at 0;

[0082] If the outdoor environment reaches the frosting condition, that is, the outdoor heat exchanger begins to frost, it enters the frosting stage; the thermal resistance of the outdoor heat exchanger increases and the heat exchange amount decreases, so the outdoor unit coil temperature continues to drop, the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature continues to increase, and the temperature difference change rate continues to increase; and as the frosting area increases, the thermal resistance further increases, the heat exchange amount further decreases, the outdoor unit coil temperature further drops, the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature further increases, and the temperature difference change rate further increases; when the outdoor heat exchanger is completely frosted, the outdoor unit coil temperature drops slower and eventually stabilizes at a lower temperature value, and similarly, the temperature difference change rate increases slower and eventually stabilizes at 0, entering the frosting completion stage;

[0083] During the frosting completion stage, the outdoor unit coil temperature will be stably maintained at a lower temperature value, and the temperature difference change rate will be stable at 0.

[0084] Therefore, in the case of a stable operation stage, if it is detected that the temperature difference change rate increases steadily and then stabilizes at 0, it is considered that the system is in the frosting completion stage and needs to be defrosted. Therefore, the outdoor heat exchanger meets the defrosting conditions.

[0085] This embodiment can accurately determine whether defrosting is required based on the temperature difference change rate on the basis of the stable operation stage.

[0086] Further, in a third embodiment of the defrost mode triggering method of the present invention proposed based on the first embodiment of the present invention, the step S40 includes the steps of:

[0087] Step S44, obtaining a preset time threshold and a heating operation time of the heating mode;

[0088] Step S45, determining whether the heating operation time is greater than the preset time threshold;

[0089] Step S46: If the heating operation time is greater than the preset time threshold, it is determined whether the outdoor heat exchanger meets the defrosting condition according to the change trend of the temperature difference change rate.

[0090] It is understandable that in the heating mode, even if the outdoor environment meets the frosting conditions, it takes a certain amount of time for the outdoor heat exchanger to frost. Therefore, in order to avoid misjudgment, a preset time threshold is set in this embodiment. Only when the heating operation time is greater than the preset time threshold, is it considered that there is a possibility of frost on the outdoor heat exchanger, and the step of judging whether the outdoor heat exchanger meets the defrosting conditions based on the temperature difference change rate is executed; the preset time threshold can be set based on the actual application scenario.

[0091] The heating operation duration is the time between the time when the heating mode is triggered and the current system time.

[0092] Further, in a fourth embodiment of the defrost mode triggering method of the present invention proposed based on the first embodiment of the present invention, the step S40 includes the steps of:

[0093] Step S47, determining a target temperature difference threshold, and judging whether the temperature difference is greater than or equal to the target temperature difference threshold;

[0094] Step S48: If the temperature difference is greater than or equal to the target temperature difference threshold, it is determined whether the outdoor heat exchanger meets the defrosting condition according to the change trend of the temperature difference change rate.

[0095] It can be understood that in the heating mode, the outdoor unit further lowers the temperature based on the outdoor temperature, and when the outdoor heat exchanger is frosted, the outdoor unit coil temperature will be significantly lower than the outdoor ambient temperature, that is, when the outdoor heat exchanger is frosted, the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature will reach a certain size; based on this, a target temperature difference threshold is set in this embodiment; when the temperature difference is greater than or equal to the target temperature difference threshold, it is considered that the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature at least meets the condition of frosting, and at this time, the step of judging whether the outdoor heat exchanger meets the defrosting condition based on the temperature difference change rate is executed; and when the temperature difference is less than the target temperature difference threshold, it is considered that the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature does not meet the condition of frosting, and frosting is impossible, therefore, the step of judging whether the outdoor heat exchanger meets the defrosting condition based on the temperature difference change rate is not executed. Thereby avoiding the execution of unnecessary operations and misjudgments.

[0096] Furthermore, the step S47 includes the steps of:

[0097] Step S471, obtaining the outdoor ambient temperature and a preset ambient temperature range, and determining whether the outdoor ambient temperature is within the preset ambient temperature range;

[0098] Step S472: if the outdoor ambient temperature is greater than the maximum value of the preset ambient temperature range, determining the target temperature difference threshold to be the first temperature difference threshold;

[0099] Step S473: if the outdoor ambient temperature is within the preset ambient temperature range, determining the target temperature difference threshold to be a second temperature difference threshold, wherein the second temperature difference threshold is less than the first temperature difference threshold;

[0100] Step S474: if the outdoor ambient temperature is lower than the minimum value of the preset ambient temperature range, the target temperature difference threshold is determined to be a third temperature difference threshold, wherein the third temperature difference threshold is lower than the second temperature difference threshold.

[0101] It is understandable that the capacity of the outdoor unit is limited, that is, in the heating mode, the cooling capacity of the outdoor heat exchanger is limited, and based on the specific outdoor ambient temperature, the specific situation of the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature when frosting occurs is also different; generally, the lower the outdoor ambient temperature, the more difficult it is to further cool down the outdoor ambient temperature, and the cooling capacity of the outdoor heat exchanger is limited, therefore, the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature will be smaller; conversely, the higher the outdoor ambient temperature, the less difficult it is to further cool down the outdoor ambient temperature, therefore, the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature will be larger.

[0102] Therefore, when setting the target temperature difference threshold, a specific value needs to be determined based on the outdoor ambient temperature; generally, the target temperature difference threshold is negatively correlated with the outdoor ambient temperature.

[0103] In this embodiment, the correspondence between the target temperature difference threshold and the outdoor ambient temperature is specifically set in the form of an interval. In other embodiments, the correspondence between the target temperature difference threshold and the outdoor ambient temperature can also be specifically set based on the negative correlation between the target temperature difference threshold and the outdoor ambient temperature.

[0104] In this embodiment, a first temperature threshold, a second temperature threshold and a third temperature threshold are pre-set from large to small; from the above analysis, it can be seen that the first temperature threshold corresponds to a higher outdoor ambient temperature, the third temperature threshold corresponds to a lower outdoor ambient temperature, and the second temperature threshold is between the first temperature threshold and the second temperature threshold; correspondingly, a preset ambient temperature interval is set, and the preset ambient temperature interval divides the outdoor ambient temperature into three parts, corresponding to the first temperature threshold, the second temperature threshold and the third temperature threshold, that is, when the outdoor ambient temperature is greater than the maximum value of the preset ambient temperature interval, the corresponding target temperature difference threshold is the first temperature threshold; when the outdoor ambient temperature is within the preset ambient temperature interval, the corresponding target temperature difference threshold is the second temperature threshold; when the outdoor ambient temperature is less than the minimum value of the preset ambient temperature interval, the corresponding target temperature difference threshold is the third temperature threshold.

[0105] In this embodiment, the corresponding target temperature difference threshold is specifically matched based on the outdoor ambient temperature, so that the obtained target temperature difference threshold can match the actual application environment and meet the requirements for defrosting condition judgment.

[0106] The following is a description of the overall implementation process of this application:

[0107] 1. The heating and frosting operation process of the heat pump unit can be defined as 4 stages:

[0108] A. Initial operation period: After the heat pump unit starts heating, the outdoor coil temperature Td drops rapidly, the temperature difference (Tc-Td) increases rapidly and then decreases, and finally reaches equilibrium, but this process is generally short;

[0109] B. Stable operation period: After the system reaches stable operation, the outdoor coil temperature Td remains basically unchanged. If the outdoor environment does not reach the frosting condition, Td remains constant, the temperature difference (Tc-Td) remains unchanged, and the temperature difference change rate η basically remains near 0;

[0110] C. Frosting period: If the outdoor environment reaches the frosting condition, the system will start to frost after running for a certain period of time. Once frosting begins, the thermal resistance of the outdoor heat exchanger increases, the heat exchange amount decreases, and the outdoor coil temperature Td also decreases. As the frosting area increases, the thermal resistance also gradually increases, and the heat transfer coefficient gradually decreases. The superposition of these two factors causes the heat exchange efficiency to deteriorate continuously, Td continues to decrease, and the rate of decrease continues to increase, that is, the rate of change of the Td curve gradually becomes steeper. In this stage, the temperature difference change rate η continues to increase, and it is a continuously increasing value;

[0111] D. Frosting completion period: At this stage, the frost of the outdoor heat exchanger is basically completed, the downward trend of the outdoor heat exchanger tube temperature Td slows down, and the temperature difference (Tc-Td) finally reaches the maximum value. At this stage, the temperature difference change rate η shows a decreasing trend, and is a continuously decreasing value, eventually approaching zero.

[0112] 2. By continuously detecting the heating operation time t, temperature difference ΔT and temperature difference change rate η of the unit, it can be determined whether the heat exchanger has completed frosting and reached the target state of defrosting. The specific control is as follows:

[0113]

[0114] Among them, T1 is the maximum value of the preset ambient temperature range, T2 is the minimum value of the preset ambient temperature range; ΔT1 is the first temperature difference threshold, ΔT2 is the second temperature difference threshold, ΔT3 is the third temperature difference threshold; ta is the preset time threshold.

[0115] 3. If the continuous operation time t of heating has reached the preset value ta, and conditions 1, 2 and 3 are met at the same time, it means that the outdoor heat exchanger has reached the target frosting state, and the defrost mode will be entered.

[0116] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0117] Through the description of the above implementation methods, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in each embodiment of the present application.

[0118] The present application also provides a defrost mode triggering device for implementing the above-mentioned defrost mode triggering method, the defrost mode triggering device comprising:

[0119] The first monitoring module is used to continuously monitor the outdoor unit coil temperature and the outdoor ambient temperature if the heating mode is triggered;

[0120] A first calculation module, used for calculating the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature;

[0121] A first judgment module is used to determine the temperature difference change rate of the temperature difference based on the continuously detected temperature difference, obtain the change trend of the temperature difference change rate, and judge whether the heating mode reaches a stable operation stage according to the change trend of the temperature difference change rate;

[0122] A second judgment module is used to judge whether the outdoor heat exchanger meets the defrosting condition according to the change trend of the temperature difference change rate if the heating mode reaches the stable operation stage;

[0123] The first switching module is used to switch to the defrost mode if the outdoor heat exchanger meets the defrost condition.

[0124] The defrost mode triggering device monitors the temperature change rate of the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature, so that the changing trend of the outdoor unit coil temperature can be determined. The change of the outdoor unit coil temperature is affected by its frosting condition. Therefore, the temperature change rate can reflect the frosting condition of the outdoor heat exchanger, and then based on the temperature change rate, it can be accurately determined whether the outdoor heat exchanger needs to be defrosted, thereby ensuring the matching of the defrost mode triggering and the frosting condition of the outdoor heat exchanger, avoiding unnecessary energy consumption, and avoiding affecting the normal operation of the air conditioner.

[0125] It should be noted that the first monitoring module in this embodiment can be used to execute step S10 in the embodiment of the present application, the first calculation module in this embodiment can be used to execute step S20 in the embodiment of the present application, the first judgment module in this embodiment can be used to execute step S30 in the embodiment of the present application, the second judgment module in this embodiment can be used to execute step S40 in the embodiment of the present application, and the first switching module in this embodiment can be used to execute step S50 in the embodiment of the present application.

[0126] Furthermore, the first determination module includes:

[0127] A first judgment unit, used to judge whether the temperature difference change rate continues to increase after the heating mode is triggered;

[0128] A second judgment unit is used to judge whether the monitored temperature difference change rate is 0 if the temperature difference change rate continues to increase;

[0129] The first determining unit is configured to determine that the heating mode reaches a stable operation stage if it is monitored that the temperature difference change rate is 0.

[0130] Furthermore, the second judgment module includes:

[0131] A third judgment unit is used to judge whether the temperature difference change rate continues to increase;

[0132] a fourth judgment unit, configured to judge whether the monitored temperature difference change rate is 0 if the temperature difference change rate continues to increase;

[0133] The second determining unit is configured to determine that the outdoor heat exchanger meets the defrosting condition if it is monitored that the temperature difference change rate is 0.

[0134] Furthermore, the second judgment module includes:

[0135] A first acquisition unit, used to acquire a preset duration threshold and a heating operation duration of the heating mode;

[0136] A fifth judgment unit, used to judge whether the heating operation time is greater than the preset time threshold;

[0137] The sixth judgment unit is used to judge whether the outdoor heat exchanger meets the defrosting condition according to the change trend of the temperature difference change rate if the heating operation time is greater than the preset time threshold.

[0138] Furthermore, the second judgment module includes:

[0139] a third determining unit, configured to determine a target temperature difference threshold, and determine whether the temperature difference is greater than or equal to the target temperature difference threshold;

[0140] The seventh judgment unit is used to judge whether the outdoor heat exchanger meets the defrosting condition according to the change trend of the temperature difference change rate if the temperature difference is greater than or equal to the target temperature difference threshold.

[0141] Further, the third determining unit includes:

[0142] A first acquisition subunit is used to acquire the outdoor ambient temperature and a preset ambient temperature range, and determine whether the outdoor ambient temperature is within the preset ambient temperature range;

[0143] a first determining subunit, configured to determine the target temperature difference threshold as a first temperature difference threshold if the outdoor ambient temperature is greater than a maximum value of the preset ambient temperature range;

[0144] a second determining subunit, configured to determine, if the outdoor ambient temperature is within the preset ambient temperature range, that the target temperature difference threshold is a second temperature difference threshold, wherein the second temperature difference threshold is less than the first temperature difference threshold;

[0145] The third determining subunit is used to determine that the target temperature difference threshold is a third temperature difference threshold if the outdoor ambient temperature is less than the minimum value of the preset ambient temperature range, wherein the third temperature difference threshold is less than the second temperature difference threshold.

[0146] Reference Figure 4 In terms of hardware structure, the air conditioner may include components such as a communication module 10, a memory 20, and a processor 30. In the air conditioner, the processor 30 is connected to the memory 20 and the communication module 10 respectively, and a computer program is stored in the memory 20. The computer program is executed by the processor 30 at the same time, and the steps of the above method embodiment are implemented when the computer program is executed.

[0147] The communication module 10 can be connected to an external communication device through a network. The communication module 10 can receive requests from an external communication device, and can also send requests, instructions and information to the external communication device, which can be other air conditioners, servers or Internet of Things devices, such as televisions, etc.

[0148] The memory 20 can be used to store software programs and various data. The memory 20 can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, at least one application required for a function (such as continuous monitoring of the outdoor unit coil temperature and the outdoor ambient temperature), etc.; the data storage area can include a database, and the data storage area can store data or information created according to the use of the system, etc. In addition, the memory 20 can include a high-speed random access memory, and can also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0149] The processor 30 is the control center of the air conditioner. It uses various interfaces and lines to connect various parts of the entire air conditioner. It executes various functions of the air conditioner and processes data by running or executing software programs and / or modules stored in the memory 20, and calling data stored in the memory 20, so as to monitor the air conditioner as a whole. The processor 30 may include one or more processing units; optionally, the processor 30 may integrate an application processor and a modem processor, wherein the application processor mainly processes the operating system, user interface, and application programs, and the modem processor mainly processes wireless communications. It is understandable that the above-mentioned modem processor may not be integrated into the processor 30.

[0150] although Figure 4 Although not shown, the air conditioner may further include a circuit control module, which is used to connect to a power source to ensure the normal operation of other components. Figure 4 The air conditioning structure shown in the figure does not constitute a limitation of the air conditioning, and may include more or less components than shown in the figure, or combine certain components, or arrange the components differently.

[0151] The present invention also provides a computer-readable storage medium on which a computer program is stored. The computer-readable storage medium may be Figure 4 The memory 20 in the air conditioner may also be at least one of a ROM (Read-Only Memory) / RAM (Random Access Memory), a magnetic disk, and an optical disk. The computer-readable storage medium includes a number of instructions for enabling a terminal device with a processor (which may be a TV, a car, a mobile phone, a computer, a server, a terminal, or a network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0152] In the present invention, the terms "first", "second", "third", "fourth" and "fifth" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0153] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0154] Although the embodiments of the present invention have been shown and described above, the scope of protection of the present invention is not limited thereto. It is understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. A person of ordinary skill in the art can change, modify and replace the above embodiments within the scope of the present invention, and these changes, modifications and replacements should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A defrost mode triggering method, characterized in that: The defrost mode triggering method comprises: If the heating mode is triggered, the outdoor unit coil temperature and outdoor ambient temperature are continuously monitored; Calculating the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature; Determining a temperature difference change rate of the temperature difference based on the continuously detected temperature difference, obtaining a change trend of the temperature difference change rate, and judging whether the heating mode has reached a stable operation stage according to the change trend of the temperature difference change rate; If the heating mode reaches a stable operation stage, judging whether the outdoor heat exchanger meets the defrosting condition according to the change trend of the temperature difference change rate; If the outdoor heat exchanger meets the defrosting condition, switching to the defrosting mode; The step of judging whether the heating mode has reached a stable operation stage according to the change trend of the temperature difference change rate includes: After the heating mode is triggered, determining whether the temperature difference change rate continues to increase; If the temperature difference change rate continues to increase, determining whether the temperature difference change rate is monitored to be 0; After the temperature difference change rate continues to increase, if the temperature difference change rate is monitored to be 0 after the temperature difference change rate decreases, or if the temperature difference change rate is detected to be 0 and the duration reaches the duration threshold, it is determined that the heating mode reaches the stable operation stage; The step of judging whether the outdoor heat exchanger meets the defrosting condition according to the change trend of the temperature difference change rate includes: Determining whether the temperature difference change rate continues to increase; If the temperature difference change rate continues to increase, determining whether the temperature difference change rate is monitored to be 0; If the monitored temperature difference change rate is 0, it is determined that the outdoor heat exchanger meets the defrosting condition.

2. The defrost mode triggering method according to claim 1, characterized in that: The step of judging whether the outdoor heat exchanger meets the defrosting condition according to the change trend of the temperature difference change rate includes: Obtaining a preset duration threshold and a heating operation duration of the heating mode; Determine whether the heating operation time is greater than the preset time threshold; If the heating operation time is greater than the preset time threshold, it is determined whether the outdoor heat exchanger meets the defrosting condition according to the change trend of the temperature difference change rate.

3. The defrost mode triggering method according to claim 1, characterized in that: The step of judging whether the outdoor heat exchanger meets the defrosting condition according to the change trend of the temperature difference change rate includes: Determine a target temperature difference threshold, and determine whether the temperature difference is greater than or equal to the target temperature difference threshold; If the temperature difference is greater than or equal to the target temperature difference threshold, it is determined whether the outdoor heat exchanger meets the defrosting condition according to the change trend of the temperature difference change rate.

4. The defrost mode triggering method according to claim 3, characterized in that: Determining the target temperature difference threshold comprises: Acquire the outdoor ambient temperature and a preset ambient temperature range, and determine whether the outdoor ambient temperature is within the preset ambient temperature range; If the outdoor ambient temperature is greater than the maximum value of the preset ambient temperature range, determining the target temperature difference threshold to be the first temperature difference threshold; If the outdoor ambient temperature is within the preset ambient temperature range, determining the target temperature difference threshold to be a second temperature difference threshold, wherein the second temperature difference threshold is less than the first temperature difference threshold; If the outdoor ambient temperature is lower than the minimum value of the preset ambient temperature range, the target temperature difference threshold is determined to be a third temperature difference threshold, wherein the third temperature difference threshold is lower than the second temperature difference threshold.

5. A defrost mode triggering device, characterized in that: The defrost mode triggering device comprises: The first monitoring module is used to continuously monitor the outdoor unit coil temperature and the outdoor ambient temperature if the heating mode is triggered; A first calculation module, used for calculating the temperature difference between the outdoor unit coil temperature and the outdoor ambient temperature; A first judgment module is used to determine the temperature difference change rate of the temperature difference based on the continuously detected temperature difference, obtain the change trend of the temperature difference change rate, and judge whether the heating mode reaches a stable operation stage according to the change trend of the temperature difference change rate; A second judgment module is used to judge whether the outdoor heat exchanger meets the defrosting condition according to the change trend of the temperature difference change rate if the heating mode reaches the stable operation stage; A first switching module, configured to switch to a defrost mode if the outdoor heat exchanger meets a defrost condition; The first judgment module includes: A first judgment unit, used to judge whether the temperature difference change rate continues to increase after the heating mode is triggered; A second judgment unit is used to judge whether the monitored temperature difference change rate is 0 if the temperature difference change rate continues to increase; A first determining unit is configured to determine that the heating mode reaches a stable operation stage if, after the temperature difference change rate continues to increase, the temperature difference change rate is monitored to be 0 after a decrease phase of the temperature difference change rate is detected, or if the temperature difference change rate is detected to be 0 and the duration reaches a duration threshold; The second judgment module includes: A third judgment unit is used to judge whether the temperature difference change rate continues to increase; a fourth judgment unit, configured to judge whether the monitored temperature difference change rate is 0 if the temperature difference change rate continues to increase; The second determining unit is configured to determine that the outdoor heat exchanger meets the defrosting condition if it is monitored that the temperature difference change rate is 0.

6. An air conditioner, characterized in that: The air conditioner comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the computer program implements the steps of the defrost mode triggering method according to any one of claims 1 to 4 when executed by the processor.

7. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the defrost mode triggering method according to any one of claims 1 to 4 are implemented.

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