Air source heat pump frost control and defrosting method and air source heat pump device

Abstract

The invention relates to the technical field of air source heat pumps, in particular to an air source heat pump frost control and defrosting method and an air source heat pump device. The frost control and defrosting method for the air source heat pump comprises the following steps that automatic defrosting is carried out after the air source heat pump is started for heating, and the saturation temperature difference value corresponding to the environment temperature and the low pressure during heating stable operation after defrosting is recorded as the frost-free temperature difference in the frost-free state; then real-time environment temperature and real-time low-pressure pressure are obtained, and a saturation temperature difference value corresponding to the real-time environment temperature and the real-time low-pressure pressure is obtained and serves as an actual temperature difference; the control system compares the actual temperature difference with the frost-free temperature difference, and when the actual temperature difference is larger than the frost-free temperature difference, the control system judges according to the temperature difference between the target outlet water temperature and the current outlet water temperature and controls the frequency of a compressor or improves the rotating speed of a direct-current fan to delay the frost layer generation rate; and when the frost accumulation operation time is up, the control system controls the unit to start defrosting. The method can reduce the defrosting frequency and improve the heat exchange efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of air source heat pumps, and in particular to an air source heat pump frost control and defrosting method and an air source heat pump device. Background Art

[0002] An air source heat pump is an energy-saving device that uses high-level energy to make heat flow from a low-level heat source, air, to a high-level heat source. It converts low-level heat energy (such as the heat contained in the air) into usable high-level heat energy, thereby achieving the purpose of saving some high-level energy (such as coal, gas, oil, electricity, etc.). Therefore, air source heat pumps have been widely promoted in China.

[0003] After heat exchange in the air source heat pump, the refrigerant will enter the evaporator to exchange heat with the air. During the heat exchange process, the refrigerant absorbs heat from the air, the air temperature outside the evaporator drops, and the water molecules in the air will adhere to the surface of the evaporator and condense into a frost layer due to the temperature difference. Too much frost will affect the heat exchange effect of the refrigerant. Therefore, in the prior art, the air source heat pump usually uses a four-way reversing valve for reverse cooling, and the defrosting is performed by stopping the fan during defrosting. However, air source heat pumps often defrost frequently, and there is a defect that the energy utilization efficiency of air source heat pumps is low. Summary of the invention

[0004] In view of this, the present invention provides an air source heat pump frost control and defrosting method and an air source heat pump device to solve the problem of frequent defrosting of the air source heat pump and the low energy utilization efficiency of the air source heat pump.

[0005] In a first aspect, the present invention provides an air source heat pump frost control and defrost method, comprising the following steps:

[0006] After turning on the heating, the machine will automatically defrost, and record the difference between the ambient temperature and the saturation temperature corresponding to the low pressure when the heating is running stably after defrosting, as the frost-free temperature difference in the frost-free state;

[0007] Then, the real-time ambient temperature and the real-time low pressure are obtained, and the saturation temperature difference corresponding to the real-time ambient temperature and the low pressure is obtained as the actual temperature difference;

[0008] The control system compares the actual temperature difference with the frost-free temperature difference. When the actual temperature difference is greater than the frost-free temperature difference, the control system makes a judgment based on the temperature difference between the target outlet water temperature and the current outlet water temperature, and controls the compressor frequency or increases the DC fan speed to slow down the frost formation rate.

[0009] When the accumulated running time of frost accumulation is reached, the control system controls the unit to start defrosting.

[0010] Beneficial effects:

[0011] When it is determined that frost is formed, the control system controls the compressor to reduce the frequency, reduce the flow of refrigerant, reduce the heat exchange in the evaporator, and delay the formation rate of the frost layer, or increase the speed of the DC fan so that the DC fan increases the air flow rate outside the evaporator. The DC fan can draw away the cold air, reduce the inlet and outlet temperature difference on the outside of the evaporator, and prevent the cold air after heat exchange from continuously surrounding the evaporator, effectively delaying the formation rate of the frost layer, which is beneficial to reduce the defrosting frequency of the air source heat pump and help improve the heat exchange efficiency of the air source heat pump.

[0012] In an optional embodiment, the method further comprises the following steps:

[0013] During the defrosting process, the high pressure value / compressor phase current value / mid-coil temperature value are obtained and compared with the set value. When the set value is exceeded, the DC fan is controlled to draw air toward the evaporator.

[0014] Beneficial effects:

[0015] By adopting the above method, the problem of forced shutdown due to excessive system pressure, which causes the frost layer at the bottom of the evaporator to be unable to melt, can be avoided. By starting the DC fan to cool and reduce the pressure on the upper part of the evaporator, the defrost time can be increased to ensure that the frost layer at the bottom of the evaporator can be completely removed, thereby preventing the frost layer at the bottom of the evaporator from being unable to melt and requiring more frequent defrosting, which is beneficial to protecting the service life of the compressor and the capacity and energy efficiency of the air source heat pump.

[0016] In an optional embodiment, the method further comprises the following steps:

[0017] When the accumulated running time of frost accumulation is reached and the actual temperature difference is greater than the frost-free temperature difference and maintained, the control system determines that there is frost and starts defrosting.

[0018] Beneficial effects:

[0019] By adopting the above defrosting method, the problems of the traditional timed defrosting and fixed value defrosting being unintelligent and the inaccurate frost layer judgment being solved, and the effect of defrosting when there is frost and not defrosting when there is no frost is achieved. While improving energy utilization, problems such as clogging of the distributor components due to excessively thick frost layers are avoided.

[0020] In an optional embodiment, the method further comprises the following steps:

[0021] When the accumulated running time for frost accumulation has not been reached and the actual temperature difference is greater than the frost-free temperature difference and is maintained, the control system determines that there is frost and starts defrosting.

[0022] Beneficial effects:

[0023] By adopting the above defrosting method, the problem of being unable to defrost the frost layer that has already been formed before the defrosting time is reached can be avoided, thereby affecting the heat exchange efficiency and wasting energy. The above method achieves the effect of defrosting when there is frost and not defrosting when there is no frost, which is beneficial to improving the heat exchange efficiency and avoiding wasting energy.

[0024] In an optional embodiment, controlling the compressor frequency or the DC fan speed to slow down the frost layer generation rate further includes the following steps:

[0025] When the current outlet water temperature is lower than the target outlet water temperature, the control system controls the compressor frequency to remain unchanged and the DC fan speed to increase to slow down the rate of frosting;

[0026] When the current outlet water temperature is lower than the target outlet water temperature and the current outlet water temperature is decreasing or maintaining, the control system controls the compressor frequency to remain unchanged and the DC fan to increase the speed to slow down the rate of frosting;

[0027] When the current outlet water temperature is lower than the target outlet water temperature and the current outlet water temperature shows an upward trend, the control system controls the wind speed of the DC fan to remain unchanged and the compressor to reduce the frequency to slow down the rate of frosting.

[0028] Beneficial effects:

[0029] By adopting the precise control of the above method, precise control of delaying frosting can be achieved, effectively extending the formation time of the frost layer, thereby reducing the number of defrosting times, which helps to improve the heat exchange efficiency of the air source heat pump and improve energy utilization.

[0030] In an optional embodiment, the method further comprises the following steps:

[0031] After the compressor frequency drops, the current outlet water temperature is detected each time and compared with the last detection record. If the current outlet water temperature changes from an upward trend to a maintained or downward trend, the compressor frequency reduction is stopped, and it is determined whether to increase or maintain the DC fan speed for frost control.

[0032] Beneficial effects:

[0033] By comparing the current water outlet temperature with the last detection record, the continuous decrease in compressor frequency, which leads to a decrease in heating efficiency, can be avoided. The above method achieves the effect of intelligent frost control and is conducive to ensuring heat exchange efficiency.

[0034] In an optional embodiment, the method further comprises the following steps:

[0035] The control system can also obtain the difference between the ambient temperature and the fin temperature during stable heating operation as the frost-free temperature difference in the frost-free state;

[0036] And, the real-time ambient temperature and the real-time fin temperature are obtained, and the difference between the real-time ambient temperature and the fin temperature is obtained as the actual temperature difference.

[0037] Beneficial effects:

[0038] The control system can also obtain the difference between the ambient temperature and the fin temperature as the frost-free temperature difference, and use the real-time difference between the ambient temperature and the fin temperature as the actual temperature difference, thereby improving the selectivity of the control system, ensuring the accuracy of frost control and defrosting, and effectively ensuring the heat exchange efficiency.

[0039] In the second aspect, the present invention also provides an air source heat pump device, which is applied to the air source heat pump frost control and defrost method described in any of the above items, including a compressor, a four-way reversing valve, an evaporator, a condenser, a DC fan and a control system, the compressor is connected to the evaporator and the condenser respectively through the four-way reversing valve, the DC fan is arranged on one side of the evaporator, the evaporator is provided with an ambient temperature sensor, and the ambient temperature sensor is connected to the control system to transmit the detected ambient temperature value to the control system; a low-pressure pressure sensor is arranged on the pipeline connecting the evaporator and the compressor, and the low-pressure pressure sensor is connected to the control system to transmit the detected low-pressure pressure value to the control system; an outlet water temperature sensor is arranged on the return water pipeline between the condenser and the floor heating pipe, and the outlet water temperature sensor is connected to the control system to transmit the detected current outlet water temperature value to the control system; the control system is electrically connected to the compressor and the DC fan, so that the control system controls the frequency of the compressor and the speed of the DC fan according to the numerical values ​​transmitted by the ambient temperature sensor, the low-pressure pressure sensor and the outlet water temperature sensor.

[0040] Because the air source heat pump device is applied to the air source heat pump frost control and defrost method, and has the same effect as the air source heat pump frost control and defrost method, it will not be repeated here.

[0041] In an optional implementation, it also includes:

[0042] A detection unit is connected to the control system, and is suitable for obtaining a high pressure value / a compressor phase current value / a middle coil temperature value and transmitting them to the control system, so that the control system starts / shuts down the DC fan to draw air toward the evaporator according to the obtained data.

[0043] In an optional implementation, the detection unit includes a high-pressure pressure sensor and / or a compressor phase electrical detection module and / or a center coil temperature sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0045] Figure 1 is a schematic diagram of an air source heat pump device according to an embodiment of the present invention;

[0046] Description of reference numerals:

[0047] 1. Compressor; 2. Four-way reversing valve; 3. Condenser; 4. Floor heating pipe; 5. Throttling device; 6. Distributor assembly; 7. Evaporator; 8. DC fan; 801. First DC fan; 802. Second DC fan; 9. Control system; 901. Main control board; 902. Compressor phase detection module; 903. Fan power supply speed control board; 10. Ambient temperature sensor; 11. Low pressure sensor; 12. Fin temperature sensor; 13. Water outlet temperature sensor; 14. High pressure sensor; 15. Middle coil temperature sensor; 16. Partition. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0049] After heat exchange in the air source heat pump, the refrigerant will enter the evaporator 7 to exchange heat with the air. During the heat exchange process, the refrigerant absorbs heat from the air, and the air temperature on the outside of the evaporator 7 continues to drop. The water molecules in the air will adhere to the surface of the evaporator 7 and condense into a frost layer. Too much frost will affect the heat exchange effect of the refrigerant. The air source heat pump usually uses the four-way reversing valve 2 for reverse cooling, and the fan is stopped for defrosting during defrosting. In the related technology, there are methods for judging the entry into defrosting, such as timed defrosting, segmented fixed-value ring-wing difference defrosting according to the ambient temperature, etc. However, the above methods do not control the formation of frost layer on the evaporator 7 and the judgment of frost layer formation is inaccurate, which will cause the air source heat pump to frequently defrost, defrost without frost, and frost without defrosting, resulting in low energy utilization efficiency of the air source heat pump.

[0050] Secondly, the fan is stopped during defrosting, and the refrigerant enters the distributor assembly 6 in the form of high-temperature gas. The fin distributor assembly 6 has multiple pipelines, which are finally connected to the evaporator 7. The pipelines close to the inlet of the distributor assembly 6 are more likely to enter more refrigerant, while the pipelines far from the inlet of the distributor assembly 6 rarely enter refrigerant. Because the evaporator 7 is arranged longitudinally, the pipelines close to the inlet of the distributor assembly 6 are connected to the upper part of the evaporator 7, and the pipelines far from the inlet of the distributor assembly 6 are connected to the middle and lower parts of the evaporator 7. Because oil is more easily accumulated in the lower pipelines, the refrigerant encounters greater resistance and therefore moves slowly. At the same time, the amount of refrigerant entering is also small, resulting in a slow heating speed, and the frost layer on the top of the evaporator 7 melts. The melted water will flow along the surface of the evaporator 7 to the lower part of the evaporator 7, which will further reduce the heating rate of the bottom. Therefore, it often happens that the frost layer on the upper part of the evaporator 7 has melted, while the frost layer on the lower part has not melted yet. Since the refrigerant continues to enter the evaporator 7, the temperature of the upper part of the evaporator 7 becomes higher and higher, and the pressure becomes higher and higher. The air source heat pump is prone to forced shutdown due to excessive system pressure during defrosting, resulting in the frost layer at the lower part of the evaporator 7 being unable to melt. Because the frost layer is not completely removed, the heat exchange efficiency cannot meet the requirements, making defrosting more frequent. The system will shut down due to excessive pressure during defrosting, which will ultimately affect the service life of the compressor 1 and the capacity and energy efficiency of the air source heat pump.

[0051] Combine the following Figure 1 , describing an embodiment of the present invention.

[0052] According to an embodiment of the present invention, on the one hand, a method for controlling frost and defrosting an air source heat pump is provided, comprising the following steps:

[0053] After turning on the heating, the machine will automatically defrost, and record the difference between the ambient temperature and the saturation temperature corresponding to the low pressure when the heating is running stably after defrosting, as the frost-free temperature difference in the frost-free state;

[0054] Then, the real-time ambient temperature and the real-time low pressure are obtained, and the saturation temperature difference corresponding to the real-time ambient temperature and the low pressure is obtained as the actual temperature difference;

[0055] The control system 9 compares the actual temperature difference with the frost-free temperature difference. When the actual temperature difference is greater than the frost-free temperature difference, the control system 9 makes a judgment based on the temperature difference between the target outlet water temperature and the current outlet water temperature, and controls the frequency of the compressor 1 or increases the speed of the DC fan 8 to slow down the rate of frost formation.

[0056] When the accumulated running time of frost accumulation is reached, the control system 9 controls the unit to start defrosting.

[0057] By adopting the air source heat pump frost control and defrost method disclosed in this embodiment, when it is determined that the frost layer is generated, the control system 9 controls the compressor 1 to reduce the frequency, reduce the flow rate of the refrigerant, reduce the heat exchange amount in the evaporator 7, and delay the generation rate of the frost layer, or increase the speed of the DC fan 8 so that the DC fan 8 increases the air flow outside the evaporator 7. The DC fan 8 quickly takes away the cold air, reduces the inlet and outlet temperature difference on the outside of the evaporator 7, and prevents the cold air after heat exchange from continuously surrounding the evaporator 7. The generation rate of the frost layer can be effectively delayed, which is beneficial to reducing the defrosting frequency of the air source heat pump and helping to improve the heat exchange efficiency of the air source heat pump.

[0058] Specifically, after starting up, the air source heat pump needs to run for 10 minutes of heating, and then defrost. After defrosting is completed, heating is performed again. After the heating is stable, the ambient temperature sensor 10 arranged on the evaporator 7 transmits the detected ambient temperature value to the control system 9, and the low-pressure pressure sensor 11 in the air source heat pump transmits the low-pressure pressure value to the control system 9. The control system 9 uses the difference between the ambient temperature during stable heating operation and the saturated temperature corresponding to the low-pressure pressure as the frost-free temperature difference in the frost-free state.

[0059] Specifically, after setting the frost-free temperature difference, the ambient temperature sensor 10 transmits the detected real-time ambient temperature value to the control system 9, and the low-pressure sensor 11 transmits the real-time low-pressure value to the control system 9. The control system 9 obtains the saturation temperature difference corresponding to the real-time ambient temperature and the low-pressure value as the actual temperature difference.

[0060] In addition, in other optional embodiments, the control system 9 can also obtain the difference between the ambient temperature detected by the ambient temperature sensor 10 and the fin temperature detected by the fin temperature sensor 12 arranged in the distributor assembly 6 when the heating is stably running, as the frost-free temperature difference in the frost-free state. The control system 9 can also obtain the real-time ambient temperature and the real-time fin temperature, and obtain the real-time ambient temperature and fin temperature difference as the actual temperature difference.

[0061] Specifically, the control system 9 compares the actual temperature difference with the frost-free temperature difference. As the frost on the evaporator 7 intensifies or the air humidity increases, the temperature difference between the actual temperature difference and the frost-free temperature difference will increase accordingly. When the actual temperature difference is greater than the frost-free temperature difference, the control system 9 will obtain the current outlet water temperature value detected by the outlet water temperature sensor 13 arranged on the return water pipe between the condenser 3 and the floor heating pipe 4, and judge the temperature difference between the current outlet water temperature and the target outlet water temperature, and adopt the method of reducing the frequency of the compressor 1, or adopt the method of increasing the speed of the DC fan 8, to delay the rate of frost formation.

[0062] It should be noted that the target water outlet temperature is the set value of the air source heat pump when it leaves the factory.

[0063] In this embodiment, when the actual temperature difference is greater than the frost-free temperature difference of 2 degrees, the control system 9 will obtain the current water outlet temperature value and the target water outlet temperature for judgment, thereby controlling the compressor 1 to reduce the frequency or increase the speed of the DC fan 8 to delay the frost layer formation rate.

[0064] In other embodiments, when the actual temperature difference is greater than the frost-free temperature difference of 2.5 degrees or 3 degrees or other temperatures, the control system 9 will obtain the current water outlet temperature value and the target water outlet temperature for judgment, and use it to control the compressor 1 to reduce the frequency or increase the speed of the DC fan 8 to delay the frost layer formation rate.

[0065] In some embodiments, when the current outlet water temperature is lower than the target outlet water temperature, the control system 9 controls the compressor 1 to keep the frequency unchanged and the DC fan 8 to increase the speed to slow down the rate of frosting;

[0066] In some embodiments, when the current outlet water temperature is lower than the target outlet water temperature and the current outlet water temperature shows a decreasing or maintaining trend, the control system 9 controls the compressor 1 to keep the frequency constant and the DC fan 8 to increase the speed to slow down the rate of frosting;

[0067] In some embodiments, when the current outlet water temperature is lower than the target outlet water temperature and the current outlet water temperature shows an upward trend, the control system 9 controls the wind speed of the DC fan 8 to remain unchanged and the compressor 1 to reduce the frequency to slow down the rate of frosting.

[0068] In this embodiment, when the current outlet water temperature is lower than the target outlet water temperature by more than 5 degrees, the control system 9 controls the frequency of the compressor 1 to remain unchanged, and the control system 9 slows down the frosting rate by increasing the speed of the DC fan 8;

[0069] When the current outlet water temperature is less than 5 degrees below the target outlet water temperature and the current outlet water temperature shows a decreasing or maintaining trend, the control system 9 controls the frequency of the compressor 1 to remain unchanged, and the control system 9 slows down the rate of frosting by increasing the speed of the DC fan 8;

[0070] When the current outlet water temperature is less than 5 degrees below the target outlet water temperature and the current outlet water temperature shows an upward trend, the control system 9 controls the wind speed of the DC fan 8 to remain unchanged, and the control system 9 slows down the frosting rate by reducing the operating frequency of the compressor 1.

[0071] It should be noted that the current outlet water temperature is compared with the target outlet water temperature only to select the compressor 1 to reduce the frequency or increase the speed of the DC fan 8 to slow down the rate of frosting. When the actual temperature difference is greater than the frost-free temperature difference by 2 degrees, the control system 9 will determine that there is a frost layer outside the evaporator 7, and then obtain the current outlet water temperature and the target outlet water temperature for comparison and judgment. When the current outlet water temperature is more than 5 degrees lower than the target outlet water temperature, and when the current outlet water temperature is less than 5 degrees lower than the target outlet water temperature and the current outlet water temperature is decreasing or maintaining a trend, the frequency of the compressor 1 is kept unchanged. , increase the speed of DC fan 8, increase the air flow outside the evaporator 7, reduce the temperature difference outside the evaporator 7, thereby reducing the frosting rate; when the current water outlet temperature is less than 5 degrees lower than the target water outlet temperature and the current water outlet temperature is on an upward trend, it proves that the indoor temperature has continued to rise, and the heat release rate of the floor heating pipe 4 has slowed down, causing the temperature inside the floor heating pipe 4 to continue to rise, resulting in the current water outlet temperature showing an upward trend. At this time, under the condition that the fan speed remains unchanged, the power of the compressor 1 can be adjusted to reduce the flow of the refrigerant, thereby reducing the heat exchange of the cold evaporator 7 and reducing the frosting rate.

[0072] Specifically, by adopting the above method, precise control can be achieved to ensure precise control of delayed frosting, effectively prolong the formation time of the frost layer, thereby reducing the number of defrosting times, which helps to improve the heat exchange efficiency of the air source heat pump and improve energy utilization.

[0073] Specifically, the DC fan 8 is set to six speeds according to the load size of the unit, from the lowest 300r / min to the highest design speed 800r / min, with each 100r / min being one speed. The maximum speed of the unit in normal operation is 700r / min, and when frost control is required, the speed runs to the maximum speed of 800r / min.

[0074] In some embodiments, after the frequency of compressor 1 decreases, the current outlet water temperature is detected each time and compared with the last detection record. If the current outlet water temperature changes from an upward trend to a maintaining or downward trend, the compressor 1 frequency reduction is stopped, and it is determined whether to increase or maintain the speed of the DC fan 8 to control frost.

[0075] In this embodiment, the frequency reduction amplitude of compressor 1 is controlled according to 5% of the current frequency. The current outlet water temperature is detected every 2 minutes and compared with the last detection record. If the current outlet water temperature changes from an upward trend to a maintenance or downward trend, the compressor 1 is stopped from reducing the frequency, and it is simultaneously determined whether it is necessary to increase the speed of DC fan 8 for frost control. If the current outlet water temperature is in a maintenance state, the speed of DC fan 8 is maintained; if the current outlet water temperature shows a downward trend, the speed of DC fan 8 needs to be increased.

[0076] Specifically, through the above-mentioned frost control method, the air source heat pump can perform effective frost control during heating operation, and the frosting time is increased from the original 45 minutes to between 60 and 90 minutes, which greatly slows down the frosting rate during the heating of the air source heat pump, reduces the defrosting frequency, and avoids the problem of low energy utilization caused by frequent defrosting.

[0077] In other embodiments, the frequency reduction amplitude of the compressor 1 may be controlled based on 4% or 3% of the current frequency.

[0078] In some embodiments, when the accumulated running time for frost accumulation is reached and the actual temperature difference is greater than the frost-free temperature difference and maintained, the control system 9 determines that there is frost and starts defrosting.

[0079] In some embodiments, when the accumulated running time of frost accumulation has not been reached and the actual temperature difference is greater than the frost-free temperature difference and is maintained, the control system 9 determines that there is frost and starts defrosting.

[0080] In this embodiment, the control system 9 compares the actual temperature difference with the frost-free temperature difference. When the cumulative operating time of frost accumulation is reached and the actual temperature difference is greater than the frost-free temperature difference by 4 degrees and maintained for 1 minute, the control system 9 determines that there is a frost layer outside the evaporator 7, and starts defrosting; when the cumulative operating time of frost accumulation is not reached, but the actual temperature difference is greater than the frost-free temperature difference by 6 degrees and maintained for 1 minute, the control system 9 determines that there is a frost layer outside the evaporator 7, and starts defrosting.

[0081] Specifically, the accumulated frost running time can be set at the factory; the control system 9 can also set the interval time between the first defrost and the second defrost after the air source heat pump is started as the accumulated frost running time, or the control system 9 sets the interval time between the first two defrosts as the accumulated frost running time.

[0082] In addition, in other embodiments, the control system 9 can use the difference between the ambient temperature detected by the ambient temperature sensor 10 and the fin temperature detected by the fin temperature sensor 12 as the frost-free temperature difference in the frost-free state, and compare it with the real-time ambient temperature and fin temperature difference obtained by the real-time ambient temperature and the real-time fin temperature as the actual temperature difference. The control system 9 compares the above-mentioned frost-free temperature difference and the actual temperature difference, and determines whether to enter the defrost state.

[0083] In other embodiments, when the cumulative running time of frost accumulation is reached and the actual temperature difference is greater than the frost-free temperature difference of 4.5 degrees or 5 degrees or other temperatures and is maintained for 1 minute, defrosting is started; when the cumulative running time of frost accumulation is not reached, but the actual temperature difference is greater than the frost-free temperature difference of 6.5 degrees or 7 degrees or other temperatures and is maintained for 1 minute, defrosting is started.

[0084] Specifically, by adopting the above defrosting method, the problems of the unintelligent nature of traditional timed defrosting and fixed-value defrosting and the inaccurate frost layer judgment are solved. The defrosting method disclosed in this embodiment achieves the effect of defrosting when there is frost and not defrosting when there is no frost. While improving energy utilization, it also avoids problems such as clogging of the evaporator 7 due to an excessively thick frost layer.

[0085] In some embodiments, during the defrosting process, the high pressure value / compressor phase current value / mid-coil temperature value are obtained and compared with the set value. When the set value is exceeded, the DC fan 8 is controlled to draw air toward the evaporator 7.

[0086] Specifically, during the defrosting process, the control system 9 obtains the high-pressure pressure value detected by the high-pressure pressure sensor 14 arranged in the air source heat pump, or the compressor phase current value detected by the compressor phase current detection module 902 arranged in the air source heat pump, or the middle coil temperature value detected by the middle coil temperature sensor 15 arranged on the distributor assembly 6, and compares them with the set value to determine in advance whether the system pressure is too high during the defrosting period. When the value obtained by the control system 9 exceeds the set value, the DC fan 8 is started to draw air toward the upper part of the evaporator 7 to lower the temperature of the upper part of the evaporator 7, thereby reducing the pressure in the evaporator 7. When the fin temperature detected by the fin temperature sensor 12 obtained by the control system 9 reaches the set temperature, the defrosting mode is exited, and the control system 9 controls the DC fan 8 to turn off or reduce the speed.

[0087] It should be noted that the set value required for the control system 9 to control the start of the DC fan 8 is obtained through experimental testing, and the set value can ensure that the air source heat pump will not shut down due to excessive pressure during the defrosting process and before the bottom of the evaporator 7 is defrosted. The set value of the high pressure, the set value of the compressor 1 phase current and the set value of the middle coil temperature are not the same.

[0088] Preferably, in the present embodiment, the control system 9 obtains the high pressure value detected by the high pressure sensor 14 provided in the air source heat pump and compares it with the set value, thereby controlling the DC fan 8 to draw air toward the evaporator 7 .

[0089] In other embodiments, the control system 9 may obtain the compressor phase current value or the middle coil temperature value and compare it with the set value.

[0090] Specifically, by adopting the above method, the problem of forced shutdown due to excessive system pressure, which leads to the inability to melt the frost layer at the bottom of the evaporator 7, can be avoided. By starting the DC fan 8 to cool and reduce the pressure on the upper part of the evaporator 7, the defrost time can be increased to ensure that the frost layer at the bottom of the evaporator 7 can be completely removed, and the inability to melt the frost layer at the bottom of the evaporator 7 can be prevented, which makes defrosting more frequent. This is beneficial to protecting the service life of the compressor 1 and the energy efficiency of the air source heat pump.

[0091] According to an embodiment of the present invention, on the other hand, an air source heat pump device is also provided, which is applied to the air source heat pump frost control and defrost method in the above embodiment, such as Figure 1 As shown, it includes: a compressor 1, a four-way reversing valve 2, an evaporator 7, a condenser 3, a DC fan 8 and a control system 9.

[0092] Specifically, the compressor 1 is connected to the evaporator 7 and the condenser 3 respectively through the four-way reversing valve 2, the DC fan 8 is arranged on one side of the evaporator 7, and the evaporator 7 is provided with an ambient temperature sensor 10, which is connected to the control system 9 to transmit the detected ambient temperature value to the control system 9. A low-pressure pressure sensor 11 is arranged on the pipeline connecting the evaporator 7 and the compressor 1, and the low-pressure pressure sensor 11 is connected to the control system 9 to transmit the detected low-pressure pressure value to the control system 9. An outlet water temperature sensor 13 is arranged on the return water pipeline between the condenser 3 and the floor heating pipe 4, and the outlet water temperature sensor 13 is connected to the control system 9 to transmit the detected current outlet water temperature value to the control system 9; the control system 9 is electrically connected to the compressor 1 and the DC fan 8, so that the control system 9 controls the frequency of the compressor 1 and the speed of the DC fan 8 according to the numerical values ​​transmitted by the ambient temperature sensor 10, the low-pressure pressure sensor 11 and the outlet water temperature sensor 13.

[0093] Specifically, Figure 1 As shown, the compressor 1 is connected to the evaporator 7 and the condenser 3 through the four-way reversing valve 2 respectively. In the heating state, the compressor 1 transports the high-temperature and high-pressure refrigerant to the condenser 3 through the four-way reversing valve 2. The condenser 3 is connected to the floor heating pipe 4. The high-temperature and high-pressure refrigerant exchanges heat with the water in the condenser 3 and the floor heating pipe 4. A throttling device 5 is provided between the condenser 3 and the evaporator 7. The refrigerant that has completed the heat exchange in the condenser 3 is converted into a low-temperature and low-pressure liquid through the throttling device 5, and enters the evaporator 7 along the pipeline, and exchanges heat with the air in the evaporator 7. The temperature of the refrigerant in the evaporator 7 is lower than the outdoor temperature, so the refrigerant absorbs heat in the evaporator 7. The refrigerant after heat exchange passes through the evaporator 7. The refrigerant passes through the four-way reversing valve 2 and enters the compressor 1 again for compression. The DC fan 8 is arranged on one side of the evaporator 7. The DC fan 8 can draw air toward the evaporator 7 when the refrigerant exchanges heat in the evaporator 7, thereby increasing the air flow rate and speeding up the heat exchange process. At the same time, it can also take away the cold air after heat exchange and reduce the temperature difference outside the evaporator 7 to slow down the frosting rate. In the defrost mode, the compressor 1 transports the high-temperature and high-pressure refrigerant to the evaporator 7 through the four-way reversing valve 2. After the high-temperature and high-pressure refrigerant enters the evaporator 7, the frost layer on the surface of the evaporator 7 can be melted. Then the refrigerant passes through the throttling device 5, the condenser 3 and the four-way reversing valve 2 in sequence and returns to the compressor 1 again.

[0094] In this embodiment, an ambient temperature sensor 10 is provided on the outer surface of the evaporator 7, and the ambient temperature sensor 10 can detect the ambient temperature value. A low-pressure pressure sensor 11 is provided on the pipeline connecting the evaporator 7 and the compressor 1, and the low-pressure pressure sensor 11 can detect the low-pressure pressure value of the air source heat pump. An outlet water temperature sensor 13 is provided on the return water pipe between the condenser 3 and the floor heating pipe 4, and the outlet water temperature sensor 13 can detect the current outlet water temperature value in the floor heating pipe 4. The ambient temperature sensor 10, the low-pressure pressure sensor 11 and the outlet water temperature sensor 13 are respectively connected to the control system 9 signal to transmit the detected ambient temperature value, low-pressure pressure value and current outlet water temperature value to the control system 9. The control system 9 sets the saturation temperature difference corresponding to the ambient temperature value and the low-pressure pressure value as the frost-free temperature difference and the actual temperature difference. The control system 9 compares the actual temperature difference with the frost-free temperature difference. When the actual temperature difference is greater than the frost-free temperature difference, the control system 9 makes a judgment based on the temperature difference between the target outlet water temperature and the current outlet water temperature. The control system 9 controls the compressor 1 to reduce the frequency or increase the speed of the DC fan 8 to delay the frost layer formation rate.

[0095] It should be noted that, by setting up the ambient temperature sensor 10, the low-pressure pressure sensor 11 and the water outlet temperature sensor 13, the control system 9 can control the compressor 1 to reduce the frequency or increase the speed of the DC fan 8 to slow down the frost layer formation rate after processing according to the data transmitted by the ambient temperature sensor 10, the low-pressure pressure sensor 11 and the water outlet temperature sensor 13, which is beneficial to reduce the defrosting frequency of the air source heat pump and help improve the heat exchange efficiency of the air source heat pump.

[0096] In this embodiment, a distributor assembly 6 is arranged between the evaporator 7, the compressor 1 and the throttling device 5. The compressor 1 is connected to the evaporator 7 through the distributor assembly 6. In the heating state, the refrigerant passing through the throttling device 5 can enter the evaporator 7 through the distributor assembly 6; in the defrosting state, the refrigerant in the compressor 1 can enter the evaporator 7 through the distributor assembly 6.

[0097] In addition, in other embodiments, a fin temperature sensor 12 is provided in the distributor assembly 6, and the fin temperature sensor 12 is connected to the control system 9 by signal. The fin temperature sensor 12 can transmit the detected fin temperature to the control system 9, and the control system 9 sets the saturation temperature difference corresponding to the ambient temperature value and the fin temperature value as the frost-free temperature difference and the actual temperature difference. The control system 9 compares the actual temperature difference with the frost-free temperature difference. When the actual temperature difference is greater than the frost-free temperature difference, the control system 9 makes a judgment based on the temperature difference between the target water outlet temperature and the current water outlet temperature. The control system 9 controls the compressor 1 to reduce the frequency or increase the speed of the DC fan 8 to slow down the frost layer formation rate.

[0098] like Figure 1As shown, in some embodiments, the DC fan 8 includes a first DC fan 801 and a second DC fan 802 , and the first DC fan 801 and the second DC fan 802 draw air toward the evaporator 7 respectively.

[0099] In this embodiment, the first DC fan 801 and the second DC fan 802 are respectively connected to the control system 9 by signal. The first DC fan 801 is arranged above the second DC fan 802. The first DC fan 801 draws air toward the upper part of the evaporator 7, and the second DC fan 802 draws air toward the lower part of the evaporator 7. The control system 9 is respectively connected to the first DC fan 801 and the second DC fan 802. In the process of delaying the formation of the frost layer, the control system 9 controls the first DC fan 801 and the second DC fan 802 to draw air toward the evaporator 7 respectively to increase the air flow rate.

[0100] like Figure 1 As shown, in some embodiments, a detection unit is further included. The detection unit is connected to the control system 9, and the detection unit is suitable for obtaining the high pressure value / compressor phase current value / intermediate coil temperature value and transmitting it to the control system 9, so that the control system 9 starts / stops the DC fan 8 to draw air toward the evaporator 7 according to the obtained data.

[0101] Preferably, in this embodiment, the detection unit can detect the high-pressure value of the air source heat pump and transmit the high-pressure value to the control system 9. In the defrost state, the control system 9 obtains the high-pressure value detected by the detection unit, and determines in advance whether the system pressure is too high during the defrost period. When the value obtained by the control system 9 exceeds the set value, the DC fan 8 is started to draw air toward the evaporator 7, thereby lowering the temperature of the upper part of the evaporator 7 and thus reducing the pressure inside the evaporator 7.

[0102] Specifically, when the value obtained by the control system 9 exceeds the set value, the control system 9 controls the first DC fan 801 to draw air to the upper part of the evaporator 7 to reduce the temperature of the upper part of the evaporator 7, thereby reducing the pressure inside the evaporator 7.

[0103] In addition, in other embodiments, the detection unit can detect the compressor phase current value of the air source heat pump and transmit the compressor phase current value to the control system 9. The control system 9 determines in advance whether the system pressure is too high during defrosting based on the compressor phase current value, and controls the first DC fan 801 to draw air to the upper part of the evaporator 7.

[0104] In other embodiments, the detection unit can detect the middle coil temperature value of the air source heat pump and transmit the middle coil temperature value to the control system 9. The control system 9 determines in advance whether the system pressure is too high during defrosting based on the middle coil temperature value, and controls the first DC fan 801 to draw air to the upper part of the evaporator 7.

[0105] It should be noted that the detection unit can detect the high pressure value / compressor phase current value / intermediate coil temperature value at the same time, or any of the above values, and the control system 9 can make a judgment based on any value and start the first DC fan 801. Preferably, in the defrosting state, the control system 9 obtains the high pressure value first.

[0106] like Figure 1 As shown, in some embodiments, a partition 16 is provided between the first DC fan 801 and the second DC fan 802 .

[0107] In this embodiment, a partition 16 is provided between the first DC fan 801 and the second DC fan 802. The partition 16 can separate the first DC fan 801 and the second DC fan 802. In the defrosting state, the first DC fan 801 draws air to the upper part of the evaporator 7. The partition 16 can isolate the wind drawn by the first DC fan 801, thereby preventing the wind drawn by the first DC fan 801 from acting on the lower part of the evaporator 7 and affecting the defrosting effect of the lower part of the evaporator 7.

[0108] It should be noted that, by detecting the high-pressure pressure value / compressor phase current value / mid-coil temperature value, the control system 9 can determine in advance whether the system pressure is too high during defrosting. If the pressure is too high, the control system 9 controls the first DC fan 801 to start drawing air toward the evaporator 7, thereby cooling and reducing the pressure on the upper part of the evaporator 7, which can increase the defrosting time. At the same time, by setting the partition 16, the wind drawn out by the first DC fan 801 can be isolated to prevent the wind drawn out by the first DC fan 801 from acting on the lower part of the evaporator 7, thereby ensuring that the frost layer on the lower part of the evaporator 7 can be completely removed, thereby preventing the frost layer on the lower part of the evaporator 7 from being unable to melt, making defrosting more frequent, which is beneficial to protecting the service life of the compressor 1 and the capacity and energy efficiency of the air source heat pump.

[0109] like Figure 1 As shown, in some embodiments, the detection unit includes a high-pressure pressure sensor 14 and / or a compressor phase electrical detection module 902 and / or a middle coil temperature sensor 15 .

[0110] Specifically, the high-pressure pressure sensor 14 is arranged on the pipeline connecting the compressor 1 and the distributor assembly 6, the compressor phase electricity detection module 902 is arranged in the control system 9, and the middle coil temperature sensor 15 is arranged on the distributor assembly 6. The high-pressure pressure sensor 14, the compressor phase electricity detection module 902 and the middle coil temperature sensor 15 are respectively connected to the control system 9 to transmit the detected high-pressure pressure value, compressor phase current value and middle coil temperature value to the control system 9.

[0111] It should be noted that, in this embodiment, the high-pressure pressure sensor 14, the compressor phase current detection module 902 and the center coil temperature sensor 15 are all arranged in the air source heat pump. Preferably, in the defrost state, the control system 9 preferentially obtains the high-pressure pressure value detected by the high-pressure pressure sensor 14, and secondly obtains the compressor phase current value detected by the compressor phase current detection module 902.

[0112] In other embodiments, the air source heat pump may only have any one or any two of the high-pressure pressure sensor 14 , the compressor phase power detection module 902 , and the middle coil temperature sensor 15 .

[0113] like Figure 1 As shown, in some embodiments, the control system 9 includes a main control board 901 , a compressor phase power detection module 902 and a fan power supply speed regulation board 903 .

[0114] In this embodiment, the compressor phase power detection module 902 is arranged on the main control board 901, and the main control board 901 is respectively connected with the compressor 1, the ambient temperature sensor 10, the low pressure sensor 11, the fin temperature sensor 12, the water outlet temperature sensor 13, the high pressure sensor 14 and the middle coil temperature sensor 15. The ambient temperature sensor 10, the low pressure sensor 11, the fin temperature sensor 12, the water outlet temperature sensor 13, the high pressure sensor 14 and the middle coil temperature sensor 15 can transmit the detected values ​​to the main control board 901, and the main control board 901 is connected with the fan power supply speed regulating board 903 by signal, and the fan power supply speed regulating board 903 is respectively connected with the first DC fan 801 and the second DC fan 802 by signal. The main control board 901 is connected with the first DC fan 801 and the second DC fan 802 by signal through the fan power supply speed regulating board 903. After judging and processing according to the received values, the main control board 901 controls the frequency of the compressor 1 or increases the speed of the DC fan 8.

[0115] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. An air source heat pump frost control and defrosting method, characterized in that: The following steps are involved: After turning on the heating, the machine will automatically defrost, and record the difference between the ambient temperature and the saturation temperature corresponding to the low pressure when the heating is running stably after defrosting, as the frost-free temperature difference in the frost-free state; Then, the real-time ambient temperature and the real-time low pressure are obtained, and the saturation temperature difference corresponding to the real-time ambient temperature and the low pressure is obtained as the actual temperature difference; The control system (9) compares the actual temperature difference with the frost-free temperature difference. When the actual temperature difference is greater than the frost-free temperature difference, the control system (9) makes a judgment based on the temperature difference between the target outlet water temperature and the current outlet water temperature, and controls the frequency of the compressor (1) or increases the speed of the DC fan (8) to slow down the rate of frost formation. When the accumulated running time due to frost accumulation is reached, the control system (9) controls the unit to start defrosting.

2. The air source heat pump frost control and defrosting method according to claim 1, characterized in that: The following steps are also included: During the defrosting process, the high pressure value / compressor phase current value / mid-coil temperature value are obtained and compared with the set value. When the set value is exceeded, the DC fan (8) is controlled to draw air toward the evaporator (7).

3. The air source heat pump frost control and defrosting method according to claim 1, characterized in that: The following steps are also included: When the accumulated running time for frost accumulation is reached and the actual temperature difference is greater than the frost-free temperature difference and is maintained, the control system (9) determines that there is frost and starts defrosting.

4. The air source heat pump frost control and defrosting method according to claim 3, characterized in that: The following steps are also included: When the accumulated running time for frost accumulation has not been reached and the actual temperature difference is greater than the frost-free temperature difference and is maintained, the control system (9) determines that frost exists and starts defrosting.

5. The air source heat pump frost control and defrosting method according to any one of claims 1 to 4, characterized in that: Controlling the frequency of the compressor (1) or the speed of the DC fan (8) to slow down the rate of frost formation also includes the following steps: When the current outlet water temperature is lower than the target outlet water temperature, the control system (9) controls the frequency of the compressor (1) to remain unchanged and the DC fan (8) to increase the rotation speed to slow down the rate of frosting; When the current outlet water temperature is lower than the target outlet water temperature and the current outlet water temperature shows a decreasing or maintaining trend, the control system (9) controls the compressor (1) to keep the frequency constant and the DC fan (8) to increase the rotation speed to slow down the rate of frosting; When the current outlet water temperature is lower than the target outlet water temperature and the current outlet water temperature shows an upward trend, the control system (9) controls the wind speed of the DC fan (8) to remain unchanged and the compressor (1) to reduce the frequency, so as to slow down the rate of frosting.

6. The air source heat pump frost control and defrosting method according to claim 5, characterized in that: The following steps are also included: After the frequency of the compressor (1) is reduced, the current outlet water temperature is detected each time and compared with the previous detection record. If the current outlet water temperature changes from an upward trend to a maintained or downward trend, the compressor (1) is stopped to reduce the frequency, and it is determined whether to increase or maintain the speed of the DC fan (8) to control frost.

7. The air source heat pump frost control and defrost method according to claim 1, characterized in that: The control system (9) can also obtain the difference between the ambient temperature and the fin temperature during stable heating operation as a frost-free temperature difference in a frost-free state; And, the real-time ambient temperature and the real-time fin temperature are obtained, and the difference between the real-time ambient temperature and the fin temperature is obtained as the actual temperature difference.

8. An air source heat pump device, applied to the air source heat pump frost control and defrost method according to any one of claims 1 to 7, comprising: A compressor (1), a four-way reversing valve (2), an evaporator (7), a condenser (3), a DC fan (8) and a control system (9), wherein the compressor (1) is connected to the evaporator (7) and the condenser (3) respectively through the four-way reversing valve (2), and the DC fan (8) is arranged on one side of the evaporator (7), and is characterized in that: The evaporator (7) is provided with an ambient temperature sensor (10), and the ambient temperature sensor (10) is connected to the control system (9) to transmit the detected ambient temperature value to the control system (9); A low-pressure sensor (11) is provided on the pipeline connecting the evaporator (7) and the compressor (1), and the low-pressure sensor (11) is connected to the control system (9) to transmit the detected low-pressure value to the control system (9); An outlet water temperature sensor (13) is provided on the return water pipe between the condenser (3) and the floor heating pipe (4); the outlet water temperature sensor (13) is connected to the control system (9) to transmit the detected current outlet water temperature value to the control system (9); The control system (9) is electrically connected to the compressor (1) and the DC fan (8) so that the control system (9) controls the frequency of the compressor (1) and the rotation speed of the DC fan (8) according to the numerical values ​​transmitted by the ambient temperature sensor (10), the low-pressure pressure sensor (11) and the outlet water temperature sensor (13).

9. The air source heat pump device according to claim 8, characterized in that: Also includes: A detection unit, the detection unit is connected to the control system (9), and the detection unit is suitable for obtaining a high-pressure pressure value / a compressor phase current value / a middle coil temperature value and transmitting it to the control system (9), so that the control system (9) starts / stops the DC fan (8) to draw air toward the evaporator (7) according to the obtained data.

10. The air source heat pump device according to claim 9, characterized in that: The detection unit includes a high-pressure pressure sensor (14) and / or a compressor phase electrical detection module (902) and / or a center coil temperature sensor (15).

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