Ultrasonic defrosting control method of heat pump unit and heat pump unit

Abstract

The invention relates to an ultrasonic defrosting control method for a heat pump unit and the heat pump unit, and the method comprises the steps: monitoring the environment temperature and the evaporation temperature of the heat pump unit and the correlation between the temperature difference change of the environment temperature and the evaporation temperature and the frosting rate and the frosting thickness of the unit, and precisely calculating the threshold values of the environment temperature, the evaporation temperature and the temperature difference at the frosting node of the unit through AI; the ultrasonic generator is controlled to start defrosting according to the environment temperature, the evaporation temperature and the relation between the temperature difference of the environment temperature and the evaporation temperature and the corresponding threshold value. According to the control method, on the premise that efficient frostless operation of the heat pump unit is achieved, defrosting starting of ultrasonic waves is intelligently controlled, and the problems that according to an existing control method based on ultrasonic defrosting, continuous work under high power causes rapid heating of a transducer, so that the resonant frequency drastically drifts, the power output efficiency is reduced, and even damage is caused are solved; meanwhile, the heat using comfort level of a user is met, the utilization efficiency of the air side heat exchanger is improved, and then the energy efficiency of the whole machine is improved.

Description

Technical Field

[0001] The invention relates to the control field of a heat pump system, and in particular to an ultrasonic defrosting control method for a heat pump unit and a heat pump unit. Background Art

[0002] Heat pump units are an efficient and environmentally friendly energy utilization technology. Its core working principle is the reverse Carnot cycle. By consuming a small amount of electricity or other energy, the heat energy in the low-temperature heat source is transferred to the high-temperature environment to achieve the purpose of heating or cooling. Heat pump units absorb low-temperature heat energy in the air with very little electricity, and convert it into high-temperature heat energy after compression by the compressor, and then transmit it to the place where heating or cooling is required. It is highly favored by consumers and users and has been widely used for refrigeration and hot water supply in hotels, schools, hospitals, saunas, beauty salons, swimming pools, laundries and other places.

[0003] When the heat pump unit is operating for heating in a cold and humid area, its finned air-side heat exchanger is very prone to frost, causing the frost to block the fin gaps, obstruct the air passage, reduce the air flow between the fins, increase the thermal resistance of the finned air-side heat exchanger, reduce the efficiency of evaporative heat exchange, and even cause unit operation failures.

[0004] In order to ensure the continuous and efficient operation of the heat pump unit, the heat exchanger used as the evaporator needs to be defrosted periodically. At present, the defrosting methods of refrigeration equipment such as air conditioners and heat pump units are mostly based on the reverse defrosting of the traditional four-way valve working valve port. This defrosting method has high energy consumption, low efficiency, and poor user experience of heat and cooling. In order to avoid the defrosting of the four-way valve reversing, the supplier adopts technologies such as double evaporator cross defrosting and ultrasonic defrosting to ensure that the user's heating and cooling needs are not interrupted and the user's comfort is guaranteed. The research on existing ultrasonic defrosting technology mainly includes two types: one is to rely on the propagation of ultrasonic waves in the air to form turbulent fluctuations of water vapor near the evaporator fins, which interferes with the frosting of water vapor on the evaporator fins; the other is to rely on the propagation of ultrasonic waves in the solid to induce mechanical vibration and shake off the frost on the surface of the evaporator fins. However, when the ultrasonic generator works continuously at high power, it will heat up sharply, causing the resonant frequency of the transducer to drift significantly, the power output efficiency to decrease, and even cause damage to the transducer and ultrasonic power supply. Therefore, it is very important to control the ultrasonic wave to start the defrosting according to the frosting condition of the heat pump unit. Summary of the invention

[0005] Based on this, an object of the present invention is to provide an ultrasonic defrosting control method for a heat pump unit.

[0006] An ultrasonic defrosting control method for a heat pump unit comprises the following steps:

[0007] Get the continuous heating operation time t of the compressor continue , cumulative heating operation time ttotal , if the continuous heating operation time t continue Greater than the set continuous heating time threshold And the cumulative heating operation time t total Greater than the set first defrost interval time threshold Then enter defrost control;

[0008] Get the current outdoor evaporation temperature

[0009] If the outdoor evaporation temperature Less than or equal to the minimum evaporation temperature threshold Then the ultrasonic generator is controlled to start defrosting;

[0010] If the outdoor evaporation temperature Greater than the minimum evaporation temperature threshold Get the current outdoor ambient temperature And determine the outdoor ambient temperature Belong to the ambient temperature range; and judge the outdoor ambient temperature Outdoor evaporation temperature and the temperature difference between the two and temperature duration t′ T , temperature difference duration t′ ΔT Whether the first defrost condition corresponding to the ambient temperature range is met:

[0011] If it is satisfied, the ultrasonic generator is controlled to start defrosting;

[0012] If not satisfied, get the defrost interval time t int. :

[0013] When the defrost interval time t int. Greater than or equal to the maximum defrost interval Determine the outdoor ambient temperature Outdoor evaporation temperature Whether the second defrosting condition is met: if so, the ultrasonic generator is controlled to start defrosting;

[0014] When the defrost interval time t int. Greater than or equal to the set second defrost interval time threshold And less than the maximum defrost interval Determine the outdoor ambient temperature and outdoor evaporation temperature Whether the temperature difference meets the third defrosting condition: if so, the ultrasonic generator is controlled to start defrosting;

[0015] Among them, the maximum defrost interval time Greater than the second defrost interval time threshold Greater than the first defrost interval time threshold

[0016] Compared with the prior art, the ultrasonic defrosting control method provided by the present invention utilizes the characteristics of ultrasonic wave with high frequency, low amplitude and efficient energy concentration, monitors the correlation between the ambient temperature, evaporation temperature and the temperature difference between the heat pump unit and the frosting rate and thickness of the unit, and uses the threshold values ​​of the ambient temperature, evaporation temperature and temperature difference at the frosting node of the unit accurately calculated by the known AI, and controls the ultrasonic generator to start defrosting by the relationship between the ambient temperature, evaporation temperature and the temperature difference between the two and the corresponding threshold values. The control method intelligently controls the start of ultrasonic defrosting on the premise of achieving efficient and frost-free operation of the heat pump unit, avoiding the problems of the existing ultrasonic defrosting control method that causes the transducer to heat rapidly and cause a large drift of the resonant frequency, a decrease in power output efficiency, or even damage due to continuous operation at high power; at the same time, it meets the user's thermal comfort, improves the utilization efficiency of the air-side heat exchanger, and thus improves the energy efficiency of the whole machine.

[0017] Furthermore, the ambient temperature range includes:

[0018] The first ambient temperature interval [T1,), where T1 is the lower limit of the temperature of the first ambient temperature interval;

[0019] The second ambient temperature interval [T2, T1), wherein T2 is the lower limit of the temperature of the second ambient temperature interval;

[0020] The third ambient temperature interval (,T2);

[0021] Among them, T1>T2.

[0022] Furthermore, the defrost start conditions corresponding to each ambient temperature range are:

[0023] The first temperature range [T1,): outdoor evaporation temperature Less than or equal to the first evaporation temperature threshold And the temperature duration t′ T Greater than or equal to the first set time t1;

[0024] The second ambient temperature interval [T2, T1): outdoor evaporation temperature Less than or equal to the second evaporation temperature threshold And the temperature duration t′ T Greater than or equal to the second set time t2;

[0025] The third ambient temperature range (T2); outdoor ambient temperature With outdoor evaporation temperature Temperature difference Greater than or equal to the temperature difference threshold And the temperature difference duration t′ΔT Greater than or equal to the third set time t3;

[0026] Among them, the first evaporation temperature threshold >Second evaporation temperature threshold

[0027] Furthermore, based on the defrost interval time t int. ,

[0028] The second defrost condition is:

[0029] Outdoor ambient temperature Less than or equal to the set first defrost start temperature And outdoor evaporation temperature Less than or equal to the set first evaporation temperature threshold

[0030] The third defrosting condition is:

[0031] Outdoor ambient temperature Less than or equal to the set second defrost start temperature And its relationship with outdoor evaporation temperature Temperature difference Less than or equal to the set temperature difference threshold and the situation lasts for a specific period of time;

[0032] The first defrost start temperature >Second defrost start temperature

[0033] Furthermore, the third ambient temperature zone includes 7 sub-temperature zones. When the lower limit value T2 of the temperature of the second ambient temperature zone is 9° C., the sub-temperature zones are divided as follows:

[0034] The first sub-temperature zone [0, 9 ° C);

[0035] The second sub-temperature zone [-5℃≤Ta<0℃);

[0036] The third sub-temperature zone [-10℃≤Ta<-5℃);

[0037] The fourth sub-temperature zone [-15℃≤Ta<-10℃);

[0038] The fifth sub-temperature zone [-20℃≤Ta<-15℃);

[0039] The sixth sub-temperature zone [-23℃≤Ta<-20℃);

[0040] The seventh sub-temperature zone (<-23℃).

[0041] Furthermore, the seven sub-temperature zones of the third ambient temperature zone correspond to seven temperature difference thresholds:

[0042] The first sub-temperature zone [0, 9°C): the corresponding first temperature difference threshold The value is -13℃;

[0043] Second sub-temperature zone [-5℃≤Ta<0℃): corresponding second temperature difference threshold is -12℃;

[0044] The third sub-temperature zone [-10℃≤Ta<-5℃): the corresponding third temperature difference threshold is -11℃;

[0045] The fourth sub-temperature zone [-15℃≤Ta<-10℃): the corresponding fourth temperature difference threshold -10℃;

[0046] The fifth sub-temperature zone [-20℃≤Ta<-15℃): the corresponding fifth temperature difference threshold -8℃;

[0047] The sixth sub-temperature zone [-23℃≤Ta<-20℃): the corresponding sixth temperature difference threshold is -6℃;

[0048] The seventh sub-temperature zone (<-23°C), the seventh temperature difference threshold The temperature is -6℃.

[0049] At the same time, the present invention also provides a heat pump unit with ultrasonic defrost control, including a compressor, a four-way valve, a water-side heat exchanger, an electronic expansion valve, an air-side heat exchanger connected through a refrigerant pipeline circulation, and an ultrasonic generator arranged on the air-side heat exchanger, and a temperature detection module, and a pressure detection module, and a controller communicatively connected to the compressor, the temperature detection module, the pressure detection module and the ultrasonic generator, the controller executes the ultrasonic defrost control method of the heat pump unit described in any of the above items.

[0050] Compared with the prior art, the heat pump unit with ultrasonic defrost control provided by the present invention has the same beneficial technical effects as the above-mentioned ultrasonic defrost control method, which will not be described in detail here.

[0051] For better understanding and implementation, the present invention is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 A schematic diagram of the system structure of an embodiment of the present invention;

[0053] Figure 2 The figure is a flow chart of a control method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0054] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention.

[0055] In order to solve the problem that the existing heat pump unit cannot accurately judge the frosting condition of the system when using ultrasonic defrosting, which causes the ultrasonic generator to be turned on for a long time for defrosting, resulting in rapid heating of the transducer, causing a large drift of the resonant frequency, a decrease in power output efficiency, and even damage; after research and debugging, the present invention proposes an ultrasonic defrosting control method for the heat pump unit. This control method monitors the correlation between the ambient temperature, evaporation temperature and the temperature difference between the ambient temperature, evaporation temperature and the temperature difference of the heat pump unit and the frosting rate and thickness of the unit, and uses the known AI to accurately calculate the thresholds of the ambient temperature, evaporation temperature and temperature difference at the node where the unit is frosted. The ultrasonic generator is controlled to start defrosting through the relationship between the ambient temperature, evaporation temperature and the temperature difference between the ambient temperature, evaporation temperature and the temperature difference between the ambient temperature and the corresponding thresholds, thereby achieving more accurate, efficient and reliable defrosting control. Among them, the AI ​​calculation uses a linear regression model to calculate the correlation between the ring fin temperature difference change rate of the fin heat exchanger as an evaporator and the system frosting rate and frosting thickness.

[0056] For specific implementation, please refer to Figure 1 Based on the ultrasonic defrosting control method, the present invention proposes a heat pump unit with ultrasonic defrosting control. The heat pump unit includes a compressor 10, a four-way valve 20, a water-side heat exchanger 30, an electronic expansion valve 40, an air-side heat exchanger 50, and an ultrasonic generator 60 arranged on one side of the air-side heat exchanger 50, a temperature detection module 70, a pressure detection module 80, a controller (not shown), and other auxiliary pipes. The controller is communicatively connected with the compressor 10, the ultrasonic generator 60, the temperature detection module 70 and the pressure detection module 80.

[0057] The temperature detection module 70 includes a first temperature sensor 71 and a second temperature sensor 72. The first temperature sensor 71 is disposed on the outer coil of the air side heat exchanger 50, and is used to collect the temperature signal of the outer coil and convert the outer coil temperature into a value. The second temperature sensor 72 is used to collect the ambient temperature. And the ambient temperature The second temperature sensor 72 can be arranged on the outside of the air-side heat exchanger 50 or on the casing of the heat pump unit, which is not limited in the present application.

[0058] The pressure detection module 80 is disposed at the return air port of the compressor 10 and is used to collect the low pressure of the refrigerant and transmit the low pressure of the refrigerant to the controller.

[0059] The controller receives the temperature signal collected by the temperature detection module 70 and the pressure signal collected by the pressure detection module 80, and calculates the evaporation temperature according to the refrigerant low pressure signal. And according to the stored calculation and judgment program, the defrosting of the system is judged, and the ultrasonic generator 60 is controlled to enter and exit the defrosting control.

[0060] For details, please refer to Figure 2 , the ultrasonic defrosting control method of the present invention includes the following steps.

[0061] 1. Start defrosting judgment

[0062] S10 obtains the continuous heating operation time t of the compressor continue :

[0063] If the continuous heating operation time is t continue Greater than the set continuous heating time threshold Right now Then execute step S20;

[0064] If the continuous heating operation time is t continue Less than or equal to the continuous heating time threshold Right now Then continue to obtain the continuous heating operation time of the compressor

[0065] S20 obtains the cumulative heating operation time t of the compressor total :

[0066] If the cumulative heating operation time t total > Set the first defrost interval time threshold Right now Then execute step S30;

[0067] If the cumulative heating operation time t total ≤ the set first defrost interval time threshold Right now Then the cumulative heating operation time t of the compressor is continuously obtained total .

[0068] Among them, when the compressor is powered on for the first time and the current outdoor ambient temperature Set the first defrost interval time For 25 minutes.

[0069] S30 obtains the current outdoor evaporation temperature

[0070] If the outdoor evaporation temperature Less than or equal to the minimum evaporation temperature threshold Then the ultrasonic generator is controlled to start defrosting;

[0071] If the outdoor evaporation temperature Greater than the minimum evaporation temperature threshold Then execute step S40.

[0072] The minimum evaporation temperature threshold It is obtained through experimental calculation. In this embodiment, its value range is -28°C to -30°C.

[0073] S40 obtains the current outdoor ambient temperature And determine the outdoor ambient temperature Belong to the ambient temperature range; and judge the outdoor ambient temperature Outdoor evaporation temperature and the temperature difference between the two and temperature duration t′ T , temperature difference duration t′ ΔT Whether the first defrost condition corresponding to the ambient temperature range is met; if the first defrost start condition is met, the ultrasonic generator is controlled to start defrosting; if not, step S50 is executed.

[0074] Specifically, it includes the following sub-steps:

[0075] S41 obtains the current outdoor ambient temperature And determine the outdoor ambient temperature The ambient temperature range includes:

[0076] The first ambient temperature interval [T1,), where T1 is the lower limit of the temperature of the first ambient temperature interval;

[0077] The second ambient temperature interval [T2, T1), where T2 is the lower limit of the temperature of the second ambient temperature interval;

[0078] The third ambient temperature interval (,T2);

[0079] Wherein, T1>T2, and its value is determined by experimental calculation. In this embodiment, the lower limit value T1 of the temperature in the first ambient temperature range is 14°C to 16°C, and the lower limit value T2 of the temperature in the second ambient temperature range is 8°C to 10°C.

[0080] Among them, the third ambient temperature interval can be further divided into several sub-temperature intervals. In this embodiment, the third ambient temperature interval is further divided into 7 sub-temperature intervals, and the lower limit value T2 of the temperature of the second ambient temperature interval is 9°C, specifically including:

[0081] The first sub-temperature zone [0, 9 ° C);

[0082] The second sub-temperature zone [-5℃≤Ta<0℃);

[0083] The third sub-temperature zone [-10℃≤Ta<-5℃);

[0084] The fourth sub-temperature zone [-15℃≤Ta<-10℃);

[0085] The fifth sub-temperature zone [-20℃≤Ta<-15℃);

[0086] The sixth sub-temperature zone [-23℃≤Ta<-20℃);

[0087] The seventh sub-temperature zone (<-23℃).

[0088] S42 determines the outdoor ambient temperature based on the determined ambient temperature range. Outdoor evaporation temperature and the temperature difference between the two and temperature duration t′ T , temperature difference duration t′ ΔT Whether the first defrost condition corresponding to the ambient temperature range is met, the first defrost start condition corresponding to each ambient temperature range is:

[0089] The first temperature range [T1,): outdoor evaporation temperature Less than or equal to the first evaporation temperature threshold And the temperature duration t′ T Greater than or equal to the first set time t1;

[0090] The second ambient temperature interval [T2, T1): outdoor evaporation temperature Less than or equal to the second evaporation temperature threshold And the temperature duration t′ T Greater than or equal to the second set time t2;

[0091] The third ambient temperature range (T2); outdoor ambient temperature With outdoor evaporation temperature Temperature difference Greater than or equal to the temperature difference threshold And the temperature difference duration t′ ΔT Greater than or equal to the third set time t3.

[0092] Among them, the temperature difference satisfy:

[0093]

[0094] In this embodiment, the first evaporation temperature threshold The value range of the second evaporation temperature is (-2℃~-1℃), The value range is (-6℃~-5℃).

[0095] The temperature difference threshold The value range is (-14℃~-1℃).

[0096] The value of the first set time t1 is greater than 1 min; the value of the second set time t2 is greater than 1 min; and the value of the third set time t3 is greater than 1 min.

[0097] Furthermore, in this embodiment, the third ambient temperature zone is divided more finely into 7 sub-temperature zones, each of which corresponds to its own temperature difference threshold, specifically:

[0098] The first sub-temperature zone [0, 9°C): the corresponding first temperature difference threshold The value is -13℃;

[0099] Second sub-temperature zone [-5℃≤Ta<0℃): corresponding second temperature difference threshold is -12℃;

[0100] The third sub-temperature zone [-10℃≤Ta<-5℃): the corresponding third temperature difference threshold is -11℃;

[0101] The fourth sub-temperature zone [-15℃≤Ta<-10℃): the corresponding fourth temperature difference threshold -10℃;

[0102] The fifth sub-temperature zone [-20℃≤Ta<-15℃): the corresponding fifth temperature difference threshold -8℃;

[0103] The sixth sub-temperature zone [-23℃≤Ta<-20℃): the corresponding sixth temperature difference threshold is -6℃;

[0104] The seventh sub-temperature zone (<-23°C), the seventh temperature difference threshold It is -6℃.

[0105] The first evaporation temperature threshold Second evaporation temperature threshold Temperature difference threshold The first evaporation temperature threshold can be obtained through experiments; Second evaporation temperature threshold Temperature difference threshold The correlation between the change of the ring-fin temperature difference of the heat pump unit and the system frost rate and system frost thickness can also be obtained through AI modeling analysis.

[0106] If the first defrost start condition is met in S43, the ultrasonic generator is controlled to start defrosting; if not, S50 is executed.

[0107] S50 obtains the defrosting interval time t int. :

[0108] If the defrost interval time t int.Greater than or equal to the set maximum defrost interval time Determine the outdoor ambient temperature Outdoor evaporation temperature Whether the second defrost condition is met:

[0109] If it is satisfied, the ultrasonic generator is controlled to start defrosting;

[0110] In other cases, the continuous defrosting interval time t int. ;

[0111] If the defrost interval time t int. Greater than or equal to the set second defrost interval time threshold And less than the maximum defrost interval Determine the outdoor ambient temperature and outdoor evaporation temperature Whether the temperature difference meets the third defrosting condition:

[0112] If it is satisfied, the ultrasonic generator is controlled to start defrosting;

[0113] In other cases, the continuous defrosting interval time t int. .

[0114] Based on the defrost interval time t int. The first defrost condition is:

[0115] Outdoor ambient temperature Less than or equal to the set first defrost start temperature And outdoor evaporation temperature Less than or equal to the set first evaporation temperature threshold

[0116] The first defrost start temperature The value range is (11℃~13℃).

[0117] Based on the defrost interval time t int. The third defrost condition is:

[0118] Outdoor ambient temperature Less than or equal to the set second defrost start temperature And its relationship with outdoor evaporation temperature Temperature difference Less than or equal to the set temperature difference threshold And the situation lasts for a specific period of time.

[0119] The second defrost start temperature The value range is (6℃~8℃).

[0120] The specific time is 1 minute.

[0121] Maximum defrost interval time Greater than the second defrost interval time threshold Greater than the first defrost interval time threshold Specifically, set the maximum defrost interval time The value range is 175min~180min; the second defrost interval time threshold The value range is 40min~45min; the first defrost interval time threshold The value range is 30min~35min.

[0122] 2. Exit defrost judgment

[0123] If any of the following conditions is met, defrosting will be terminated:

[0124] AThe defrost operation time is greater than or equal to the maximum defrost operation time.

[0125] B The current outdoor ambient temperature is greater than or equal to the defrost exit ambient temperature threshold, and the coil temperature is greater than or equal to the defrost exit first external coil temperature threshold, and the duration is greater than or equal to the coil temperature exit time.

[0126] C The current outdoor ambient temperature is greater than or equal to the defrost exit ambient temperature threshold, and the coil temperature is greater than or equal to the defrost exit second external coil temperature threshold, and the duration is greater than or equal to the AI ​​defrost exit time.

[0127] D The current outdoor ambient temperature is lower than the defrost exit ambient temperature threshold, but the coil temperature is greater than or equal to the AI ​​defrost coil exit temperature, and the duration is greater than or equal to the AI ​​defrost exit time.

[0128] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the embodiments of the present application. The singular forms of "a", "said" and "the" used in the embodiments of the present application and the claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that, unless otherwise specified, "multiple" and "several" refer to two or more; "and / or" refers to and includes any or all possible combinations of one or more associated listed items; "first", "second", "third", etc. are only used to distinguish, rather than to describe a specific order or sequence, and cannot be understood as indicating or implying relative importance. When the above description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. In the description of the present application, for those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0129] The above-mentioned embodiments only express several implementation methods of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, and the present invention is also intended to include these modifications and modifications.

Claims

1. An ultrasonic defrosting control method for a heat pump unit, characterized in that: The following steps are involved: Get the continuous heating operation time t of the compressor continue , cumulative heating operation time t total , if the continuous heating operation time t continue Greater than the set continuous heating time threshold And the cumulative heating operation time t total Greater than the set first defrost interval time threshold Then enter defrost control; Get the current outdoor evaporation temperature If the outdoor evaporation temperature Less than or equal to the minimum evaporation temperature threshold Then the ultrasonic generator is controlled to start defrosting; If the outdoor evaporation temperature Greater than the minimum evaporation temperature threshold Get the current outdoor ambient temperature And determine the outdoor ambient temperature The ambient temperature range; And judge the outdoor ambient temperature Outdoor evaporation temperature and the temperature difference between the two and temperature duration t′ T , temperature difference duration t′ ΔT Whether the first defrost condition corresponding to the ambient temperature range is met: If it is satisfied, the ultrasonic generator is controlled to start defrosting; If not satisfied, get the defrost interval time t int. : When the defrost interval time t int. Greater than or equal to the maximum defrost interval Determine the outdoor ambient temperature Outdoor evaporation temperature Whether the second defrosting condition is met: if so, the ultrasonic generator is controlled to start defrosting; When the defrost interval time t int. Greater than or equal to the set second defrost interval time threshold And less than the maximum defrost interval Determine the outdoor ambient temperature and outdoor evaporation temperature Whether the temperature difference meets the third defrosting condition: if so, the ultrasonic generator is controlled to start defrosting; Among them, the maximum defrost interval time Greater than the second defrost interval time threshold Greater than the first defrost interval time threshold 2. The ultrasonic defrosting control method of a heat pump unit according to claim 1, characterized in that: The ambient temperature range includes: The first ambient temperature interval [T1,), where T1 is the lower limit of the temperature of the first ambient temperature interval; The second ambient temperature interval [T2, T1), wherein T2 is the lower limit of the temperature of the second ambient temperature interval; The third ambient temperature interval (,T2); Among them, T1>T2.

3. The ultrasonic defrosting control method for a heat pump unit according to claim 1, characterized in that: The defrost start conditions corresponding to each ambient temperature range are: The first temperature range [T1,): outdoor evaporation temperature Less than or equal to the first evaporation temperature threshold And the temperature duration t′ T Greater than or equal to the first set time t1; The second ambient temperature interval [T2, T1): outdoor evaporation temperature Less than or equal to the second evaporation temperature threshold And the temperature duration t′ T Greater than or equal to the second set time t2; The third ambient temperature range (T2); outdoor ambient temperature With outdoor evaporation temperature Temperature difference Greater than or equal to the temperature difference threshold And the temperature difference duration t′ ΔT Greater than or equal to the third set time t3; Among them, the first evaporation temperature threshold >Second evaporation temperature threshold 4. The ultrasonic defrosting control method of a heat pump unit according to claim 3, characterized in that: The first evaporation temperature threshold The value range (-2℃~-1℃), the second evaporation temperature threshold (-6℃~-5℃) and temperature difference threshold The value range is (-14℃~-1℃).

5. The ultrasonic defrosting control method for a heat pump unit according to claim 3 or 4, characterized in that: Based on the defrost interval time t int. , The second defrost condition is: Outdoor ambient temperature Less than or equal to the set first defrost start temperature And outdoor evaporation temperature Less than or equal to the set first evaporation temperature threshold The third defrosting condition is: Outdoor ambient temperature Less than or equal to the set second defrost start temperature And its relationship with outdoor evaporation temperature Temperature difference Less than or equal to the set temperature difference threshold and the situation lasts for a specific period of time; The first defrost start temperature >Second defrost start temperature 6. The ultrasonic defrosting control method of a heat pump unit according to claim 5, characterized in that: The first defrost start temperature The value range of the second defrost start temperature is (11℃~13℃). The value range is (6℃~8℃).

7. The ultrasonic defrosting control method for a heat pump unit according to any one of claims 2, 3, 4 and 6, characterized in that: The third ambient temperature zone includes 7 sub-temperature zones. When the lower limit value T2 of the temperature of the second ambient temperature zone is 9°C, the sub-temperature zones are divided as follows: The first sub-temperature zone [0, 9 ° C); The second sub-temperature zone [-5℃≤Ta<0℃); The third sub-temperature zone [-10℃≤Ta<-5℃); The fourth sub-temperature zone [-15℃≤Ta<-10℃); The fifth sub-temperature zone [-20℃≤Ta<-15℃); The sixth sub-temperature zone [-23℃≤Ta<-20℃); The seventh sub-temperature zone (<-23℃).

8. The ultrasonic defrosting control method for a heat pump unit according to claim 7, characterized in that: The seven sub-temperature zones of the third ambient temperature zone correspond to seven temperature difference thresholds: The first sub-temperature zone [0, 9°C): the corresponding first temperature difference threshold The value is -13℃; Second sub-temperature zone [-5℃≤Ta<0℃): corresponding second temperature difference threshold is -12℃; The third sub-temperature zone [-10℃≤Ta<-5℃): the corresponding third temperature difference threshold is -11℃; The fourth sub-temperature zone [-15℃≤Ta<-10℃): the corresponding fourth temperature difference threshold -10℃; The fifth sub-temperature zone [-20℃≤Ta<-15℃): the corresponding fifth temperature difference threshold -8℃; The sixth sub-temperature zone [-23℃≤Ta<-20℃): the corresponding sixth temperature difference threshold is -6℃; The seventh sub-temperature zone (<-23°C), the seventh temperature difference threshold It is -6℃.

9. The ultrasonic defrosting control method for a heat pump unit according to claim 1, characterized in that: It also includes defrost exit judgment. If the heat pump unit meets any of the following conditions, it will exit ultrasonic defrost: A. The defrost operation time is greater than or equal to the maximum defrost operation time; B. The current outdoor ambient temperature is greater than or equal to the defrost exit ambient temperature threshold, and the coil temperature is greater than or equal to the first defrost exit external coil temperature threshold, and the duration is greater than or equal to the coil temperature exit time; C The current outdoor ambient temperature is greater than or equal to the defrost exit ambient temperature threshold, and the coil temperature is greater than or equal to the second defrost exit external coil temperature threshold, and the duration is greater than or equal to the AI ​​defrost exit time; D The current outdoor ambient temperature is lower than the defrost exit ambient temperature threshold, but the coil temperature is greater than or equal to the AI ​​defrost coil exit temperature, and the duration is greater than or equal to the AI ​​defrost exit time.

10. A heat pump unit with ultrasonic defrost control, comprising: A compressor, a four-way valve, a water-side heat exchanger, an electronic expansion valve, an air-side heat exchanger connected through a refrigerant pipeline circulation, an ultrasonic generator arranged on the air-side heat exchanger, a temperature detection module, a pressure detection module, and a controller communicatively connected to the compressor, the temperature detection module, the pressure detection module and the ultrasonic generator, characterized in that the controller executes the ultrasonic defrost control method for the heat pump unit as described in any one of claims 1 to 9.

Images