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

Abstract

The present application relates to air source heat pump technical field, specifically to air source heat pump frost control and defrosting method and air source heat pump device.The air source heat pump frost control and defrosting method, comprising the following steps: after starting heating, automatic defrosting is carried out, and the saturated temperature difference corresponding to the environment temperature and low pressure pressure during the stable operation of heating after defrosting is recorded as the frost-free temperature difference of frost-free state; subsequently, real-time environment temperature and real-time low pressure pressure are obtained, and the saturated temperature difference corresponding to the real-time environment temperature and low pressure pressure is obtained as the actual temperature difference; 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 judges according to the temperature difference between the target outlet water temperature and the current outlet water temperature, controls the compressor frequency or improves the direct current fan speed to delay the frost layer formation rate; when the accumulated frost accumulation running time is reached, the control system controls the unit to start defrosting.The above method can reduce the defrosting frequency and improve the heat exchange efficiency.

Description

Technical Field

[0001] This invention relates to the field of air source heat pump technology, specifically to air source heat pump defrosting and defrosting methods and air source heat pump devices. Background Technology

[0002] An air source heat pump is an energy-saving device that uses high-grade energy to transfer heat from a low-grade heat source, air, to a high-grade heat source. By converting low-grade heat energy (such as the heat contained in air) into usable high-grade heat energy, it achieves the goal of saving some high-grade energy (such as coal, gas, oil, electricity, etc.). Therefore, air source heat pumps have been widely promoted in China.

[0003] After heat exchange, the refrigerant in an air source heat pump enters the evaporator to exchange heat with the air. During this process, the refrigerant absorbs heat from the air, causing the air temperature outside the evaporator to drop. Water molecules in the air adhere to the evaporator surface and condense into frost due to the temperature difference. Excessive frost can affect the heat exchange efficiency of the refrigerant. Therefore, in existing technologies, air source heat pumps typically use a four-way reversing valve for reverse cooling and defrost by stopping the fan during defrosting. However, air source heat pumps often experience frequent defrosting, resulting in low energy efficiency. Summary of the Invention

[0004] In view of this, the present invention provides a defrosting and control method and an air source heat pump device for air source heat pumps, in order to solve the problem that air source heat pumps will frequently require defrosting and have low energy utilization efficiency.

[0005] In a first aspect, the present invention provides a method for defrosting and controlling defrosting an air source heat pump, comprising the following steps:

[0006] After the heating is turned on, automatic defrosting is performed, and the difference between the ambient temperature and the saturation temperature corresponding to the low pressure during stable heating operation after defrosting is recorded as the frost-free temperature difference in the frost-free state.

[0007] Then, the real-time ambient temperature and real-time low pressure are obtained, and the difference between the real-time ambient temperature and the low pressure corresponding to the saturation temperature 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 judges 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 cumulative frost accumulation time is reached, the control system initiates defrosting of the unit.

[0010] Beneficial effects:

[0011] When the frost layer is generated, the control system controls the compressor to reduce the frequency, reduces the flow of refrigerant, reduces the heat exchange in the evaporator, delays the generation rate of the frost layer, or increases the speed of the DC fan to increase the air flow rate outside the evaporator. The DC fan can draw cold air away, reduce the temperature difference between the inlet and outlet of the evaporator, prevent the cold air after heat exchange from surrounding the evaporator, effectively delay the generation rate of the frost layer, 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 alternative embodiment, the method further comprises the steps of:

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

[0014] Advantages:

[0015] By using the above method, the problem of forced protection shutdown due to high system pressure, which causes the frost layer at the lower part of the evaporator to be unable to melt, can be avoided. By starting the DC fan to cool and depressurize the upper part of the evaporator, the defrosting time can be improved, ensuring that the frost layer at the lower part of the evaporator can be completely removed, preventing the frost layer at the lower part of the evaporator from melting, and making defrosting more frequent, 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 alternative embodiment, the method further comprises the steps of:

[0017] When the accumulated frost accumulation running time is 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.

[0018] Advantages:

[0019] By using the above defrosting method, the problems of unintelligent and inaccurate frost layer judgment of traditional timed defrosting and fixed value defrosting are solved, the effect of frost defrosting and no frost defrosting is achieved, the energy utilization rate is improved, and the problems of blockage of the distributor assembly due to excessive frost layer thickness are avoided.

[0020] In an alternative embodiment, the method further comprises the steps of:

[0021] When the accumulated frost accumulation running time is not 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] Advantages:

[0023] By using the above defrosting method, the problem that the frost layer generated cannot be defrosted before the defrosting time, thereby affecting the heat exchange efficiency and wasting energy, is avoided, and the effect of frost defrosting and no frost defrosting is realized, which is beneficial to improve the heat exchange efficiency and avoid wasting energy.

[0024] In an alternative embodiment, the compressor frequency or DC fan speed delay frost formation rate further comprises the following steps:

[0025] When the current outlet water temperature is less than the target outlet water temperature, the control system controls the compressor frequency to remain unchanged, and the DC fan increases the speed to delay the frost formation rate;

[0026] When the current outlet water temperature is less than the target outlet water temperature and the current outlet water temperature is in a downward or maintaining trend, the control system controls the compressor frequency to remain unchanged, and the DC fan increases the speed to delay the frost formation rate;

[0027] When the current outlet water temperature is less than the target outlet water temperature and the current outlet water temperature is in an upward trend, the control system controls the DC fan speed to remain unchanged, and the compressor reduces the frequency to delay the frost formation rate.

[0028] Advantages:

[0029] By using the above method for precise control, the precise control of the frost delay is realized, the frost formation time is effectively prolonged, the defrosting frequency is reduced, the heat exchange efficiency of the air source heat pump is improved, and the energy utilization rate is improved.

[0030] In an alternative embodiment, the following steps are further included:

[0031] After the compressor frequency is reduced, the current outlet water temperature is detected once every time, and compared with the last detection record.

[0032] Advantages:

[0033] By comparing the current outlet water temperature with the last detection record, the continuous reduction of the compressor frequency, which leads to the reduction of the heating efficiency, can be avoided, and the effect of intelligent frost control is realized, which is beneficial to ensure the heat exchange efficiency.

[0034] In an alternative embodiment, the following steps are further included:

[0035] The control system can also obtain the difference between the environment temperature and the fin temperature during the 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 acquired, and a real-time ambient temperature and fin temperature difference is obtained as an actual temperature difference.

[0037] Beneficial effects:

[0038] The control system can also improve the selectivity of the control system by acquiring the ambient temperature and fin temperature difference as a frostless temperature difference, and the real-time ambient temperature and fin temperature difference as an actual temperature difference, which is conducive to ensuring the accuracy of frost control and defrosting, and effectively ensuring the heat exchange efficiency.

[0039] In a second aspect, the present application also provides an air source heat pump device applied to the air source heat pump frost control and defrosting method, comprising a compressor, a four-way reversing valve, an evaporator, a condenser, a direct current fan and a control system, the compressor is communicated with the evaporator and the condenser through the four-way reversing valve, the direct current fan is arranged on one side of the evaporator, an ambient temperature sensor is arranged on the evaporator, and the ambient temperature sensor is connected with the control system to transmit the detected ambient temperature value to the control system; a low-pressure pressure sensor is arranged on the pipeline connected with the compressor, and the low-pressure pressure sensor is connected with the control system to transmit the detected low-pressure pressure value to the control system; a water outlet temperature sensor is arranged on the return water pipeline of the ground heating pipe connected with the condenser, and the water outlet temperature sensor is connected with the control system to transmit the detected current water outlet temperature value to the control system; the control system is electrically connected with the compressor and the direct current fan, so that the control system controls the frequency of the compressor and the rotating speed of the direct current fan according to the values transmitted by the ambient temperature sensor, the low-pressure pressure sensor and the water outlet temperature sensor.

[0040] Since the air source heat pump device is applied to the air source heat pump frost control and defrosting method, it has the same effect as the air source heat pump frost control and defrosting method, which will not be described here.

[0041] In an optional embodiment, it also comprises:

[0042] A detection unit connected with the control system, the detection unit is adapted to acquire the high-pressure pressure value / compressor phase current value / intermediate coil temperature value and transmit them to the control system, so that the control system starts / closes the direct current fan to draw air to the evaporator according to the obtained data.

[0043] In an optional embodiment, the detection unit comprises a high-pressure pressure sensor and / or a compressor phase current detection module and / or an intermediate coil temperature sensor. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the description of the specific embodiments or the prior art. Obviously, the drawings described below are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0045] Figure 1 A schematic view of an air source heat pump device according to an embodiment of the present application;

[0046] Explanation of reference signs:

[0047] 1, compressor; 2, four-way reversing valve; 3, condenser; 4, floor heating pipe; 5, throttling device; 6, distributor assembly; 7, evaporator; 8, direct current fan; 801, first direct current fan; 802, second direct current fan; 9, control system; 901, main control board; 902, compressor phase detection module; 903, fan power speed regulation board; 10, ambient temperature sensor; 11, low pressure pressure sensor; 12, fin temperature sensor; 13, water outlet temperature sensor; 14, high pressure pressure sensor; 15, middle coil temperature sensor; 16, partition. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0049] The refrigerant after heat exchange of the air source heat pump enters the evaporator 7 to exchange heat with air. In the heat exchange process, the refrigerant absorbs heat from the air, and the temperature of the air outside 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 layer will affect the heat exchange effect of the refrigerant. The air source heat pump usually reverses the refrigeration through the four-way reversing valve 2, and defrosting is performed by stopping the fan during defrosting. In the related art, the ways to determine defrosting include timed defrosting, segmented constant value ring fin difference defrosting according to the ambient temperature, etc. However, the above ways do not control the formation of the frost layer on the evaporator 7 and the judgment of the formation of the frost layer is not accurate, which will cause the air source heat pump to appear frequent defrosting, no defrosting and defrosting with frost, resulting in low energy utilization efficiency of the air source heat pump.

[0050] Secondly, during defrosting, the fan is stopped, and the refrigerant enters the distributor assembly 6 in the form of high-temperature gas. The fin distributor assembly 6 has a plurality of pipelines, which are finally communicated with 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 have less refrigerant entering. Since the evaporator 7 is arranged longitudinally, the pipelines close to the inlet of the distributor assembly 6 are communicated with the upper part of the evaporator 7, and the pipelines far from the inlet of the distributor assembly 6 are communicated with the middle and lower parts of the evaporator 7. Since the lower pipelines are more likely to accumulate oil, the refrigerant has greater resistance and thus moves slowly, and the amount of refrigerant entering is also less, resulting in slow heating speed. In addition, the water melted from the frost layer on the upper part of the evaporator 7 flows along the surface of the evaporator 7 to the lower part of the evaporator 7, further reducing the heating speed of the bottom. Therefore, the frost layer on the upper part of the evaporator 7 has been melted, while the frost layer on the lower part has not been melted. Since the refrigerant is always entering the evaporator 7, the temperature of the upper part of the evaporator 7 is getting higher and higher, and the pressure is also getting higher and higher. The air source heat pump is prone to forced protection shutdown due to high system pressure during defrosting, which causes the frost layer on the lower part of the evaporator 7 to be unable to melt. Since the frost layer is not completely removed, the heat exchange efficiency cannot meet the demand, which makes the defrosting more frequent, and the system is protected to stop due to high pressure during defrosting, ultimately affecting the service life of the compressor 1 and the capacity and energy efficiency of the air source heat pump.

[0051] The embodiments of the present application will be described below in conjunction with Figure 1

[0052] According to the embodiments of the present application, in one aspect, an air source heat pump defrosting and defrosting method is provided, comprising the following steps:

[0053] After starting the heating, automatic defrosting is performed, and the difference between the saturation temperature corresponding to the ambient temperature and the low-pressure pressure during the stable operation of the heating after defrosting is recorded as the frost-free temperature difference in the frost-free state;

[0054] Subsequently, the real-time ambient temperature and the real-time low-pressure pressure are obtained, and the difference between the saturation temperature corresponding to the real-time ambient temperature and the real-time low-pressure 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 judges according to the temperature difference between the target outlet water temperature and the current outlet water temperature, controls the frequency of the compressor 1 or increases the rotating speed of the direct-current fan 8 to delay the frost layer generation rate;

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

[0057] ​When it is determined that frost layer is generated, the control system 9 controls the compressor 1 to reduce the frequency, reduces the flow of refrigerant, reduces the heat exchange amount in the evaporator 7, delays the generation rate of the frost layer, or increases the rotating speed of the direct current fan 8, so that the direct current fan 8 increases the air flow outside the evaporator 7, the direct current fan 8 quickly takes away the cold air, reduces the temperature difference of the in-out air outside the evaporator 7, prevents the cold air after heat exchange from continuously surrounding the evaporator 7, effectively delays the generation rate of the frost layer, is beneficial to reduce the defrosting frequency of the air source heat pump, and is helpful to improve the heat exchange efficiency of the air source heat pump.

[0058] Specifically, after starting, the air source heat pump needs to be heated for 10 minutes, and then defrosting is performed, after defrosting is completed, heating is performed again, after the heating is stable, the environment temperature sensor 10 arranged on the evaporator 7 transmits the detected environment temperature value to the control system 9, the low-pressure pressure sensor 11 in the air source heat pump transmits the low-pressure pressure value to the control system 9, and the control system 9 takes the saturation temperature difference corresponding to the environment temperature and the low-pressure pressure when the heating is stably operated as the frost-free temperature difference in the frost-free state.

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

[0060] In addition, in other optional embodiments, the control system 9 can also obtain the temperature difference between the environment temperature detected by the environment 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 operated as the frost-free temperature difference in the frost-free state, and the control system 9 can also obtain the real-time environment temperature and the real-time fin temperature, and obtain the real-time temperature difference between the real-time environment temperature and the fin temperature as the actual temperature difference.

[0061] Specifically, the control system 9 compares the actual temperature difference with the frost-free temperature difference, and when the evaporator 7 is more and more frosted or the air humidity is increased, the temperature difference between the actual temperature difference and the frost-free temperature difference will be increased, when the actual temperature difference is greater than the frost-free temperature difference, the control system 9 obtains the current outlet water temperature value detected by the outlet water temperature sensor 13 arranged on the return water pipeline of the condenser 3 and the ground heating pipe 4, and judges the temperature difference between the current outlet water temperature and the target outlet water temperature, and delays the generation rate of the frost layer by reducing the frequency of the compressor 1 or increasing the rotating speed of the direct current fan 8.

[0062] It should be noted that the target outlet water temperature is a set value when the air source heat pump is shipped.

[0063] In the present embodiment, when the actual temperature difference is greater than the frostless temperature difference by 2 degrees, the control system 9 obtains the current outlet water temperature value and the target outlet water temperature to determine whether to control the compressor 1 to reduce the frequency or to increase the rotation speed of the direct-current fan 8 to delay the frost layer formation rate.

[0064] In other embodiments, when the actual temperature difference is greater than the frostless temperature difference by 2.5 degrees or 3 degrees or other temperatures, the control system 9 obtains the current outlet water temperature value and the target outlet water temperature to determine whether to control the compressor 1 to reduce the frequency or to increase the rotation speed of the direct-current fan 8 to delay the frost layer formation rate.

[0065] In some embodiments, when the current outlet water temperature is less than the target outlet water temperature, the control system 9 controls the compressor 1 frequency to remain unchanged and the direct-current fan 8 to increase the rotation speed to delay the frost formation rate.

[0066] In some embodiments, when the current outlet water temperature is less than the target outlet water temperature and the current outlet water temperature is in a downward or maintaining trend, the control system 9 controls the compressor 1 frequency to remain unchanged and the direct-current fan 8 to increase the rotation speed to delay the frost formation rate.

[0067] In some embodiments, when the current outlet water temperature is less than the target outlet water temperature and the current outlet water temperature is in an upward trend, the control system 9 controls the direct-current fan 8 wind speed to remain unchanged and the compressor 1 to reduce the frequency to delay the frost formation rate.

[0068] In the present embodiment, when the current outlet water temperature is less than the target outlet water temperature by 5 degrees or more, the control system 9 controls the compressor 1 frequency to remain unchanged and the control system 9 to increase the rotation speed of the direct-current fan 8 to delay the frost formation rate.

[0069] When the current outlet water temperature is less than the target outlet water temperature by 5 degrees or less and the current outlet water temperature is in a downward or maintaining trend, the control system 9 controls the compressor 1 frequency to remain unchanged and the control system 9 to increase the rotation speed of the direct-current fan 8 to delay the frost formation rate.

[0070] When the current outlet water temperature is less than the target outlet water temperature by 5 degrees or less and the current outlet water temperature is in an upward trend, the control system 9 controls the direct-current fan 8 wind speed to remain unchanged and the control system 9 to reduce the compressor 1 operating frequency to delay the frost formation rate.

[0071] It should be noted that the comparison between the current outlet water temperature and the target outlet water temperature is only for selecting to delay the frosting rate by reducing the frequency of the compressor 1 or increasing the rotating speed of the direct current fan 8, when the actual temperature difference is greater than the frost-free temperature difference of 2 degrees, the control system 9 will determine that there is a frost layer outside the evaporator 7, and then compare the current outlet water temperature with the target outlet water temperature, when the current outlet water temperature is less than the target outlet water temperature by more than 5 degrees, and when the current outlet water temperature is less than the target outlet water temperature by less than 5 degrees and the current outlet water temperature is in a downward or maintaining trend, the frequency of the compressor 1 is kept unchanged, the rotating speed of the direct current fan 8 is increased, the air flow outside the evaporator 7 is increased, and the temperature difference outside the evaporator 7 is reduced, so as to reduce the frosting rate; when the current outlet water temperature is less than the target outlet water temperature by less than 5 degrees and the current outlet water temperature is in an upward trend, it is proved that the indoor temperature has been continuously increased, the heat release speed of the floor heating pipe 4 is slowed down, the temperature in the floor heating pipe 4 continues to rise, and the current outlet water temperature is in an upward trend, at this time, the power of the compressor 1 can be adjusted under the condition that the rotating speed of the fan is unchanged, so as to reduce the flow of the refrigerant, thereby reducing the heat exchange amount of the evaporator 7 and reducing the frosting rate.

[0072] Specifically, by using the above method, precise control can be realized to ensure the precise control of delaying frosting, effectively prolong the generation time of the frost layer, thereby reducing the defrosting frequency, helping to improve the heat exchange efficiency of the air source heat pump and improve the energy utilization rate.

[0073] Specifically, the direct current fan 8 is set to six rotating speeds according to the different sizes of the unit load, from the lowest 300 r / min to the highest design rotating speed 800 r / min, and every 100 r / min is a gear. The maximum rotating speed of the unit in normal operation is 700 r / min, and when frost control is needed, the rotating speed runs to the highest rotating speed 800 r / min.

[0074] In some embodiments, after the frequency of the compressor 1 is reduced, the current outlet water temperature is detected once every time, compared with the last detection record, if the current outlet water temperature changes from an upward trend to a maintaining or downward trend, the frequency reduction of the compressor 1 is stopped, and it is judged whether to increase or maintain the rotating speed of the direct current fan 8 for frost control.

[0075] In this embodiment, the reduction amplitude of the frequency of the compressor 1 is controlled according to 5% of the current frequency, the current outlet water temperature is detected once every 2 minutes, 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 frequency reduction of the compressor 1 is stopped, and it is simultaneously judged whether the rotating speed of the direct current fan 8 needs to be increased for frost control, if the current outlet water temperature is in a maintaining state, the rotating speed of the direct current fan 8 is maintained; if the current outlet water temperature is in a downward trend, the rotating speed of the direct current fan 8 needs to be increased.

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

[0077] In other embodiments, the compressor 1 frequency reduction range can be controlled according to 4% or 3% of the current frequency.

[0078] In some embodiments, when 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.

[0079] In some embodiments, when 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 frosting cumulative running time is reached, and the actual temperature difference is greater than the frost-free temperature difference by 4 degrees and is maintained for 1 minute, the control system 9 determines that there is frost on the evaporator 7, i.e. starts defrosting; when the frosting cumulative running time is not reached, but the actual temperature difference is greater than the frost-free temperature difference by 6 degrees and is maintained for 1 minute, the control system 9 determines that there is frost on the evaporator 7, i.e. starts defrosting.

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

[0082] In addition, in other embodiments, the control system 9 can compare 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, with the difference between the real-time ambient temperature and the real-time fin temperature obtained from the real-time ambient temperature and the real-time fin temperature as the actual temperature difference. The control system 9 compares the above frost-free temperature difference and actual temperature difference, and determines whether to enter the defrosting state.

[0083] In other embodiments, when the frosting cumulative running time is reached, and the actual temperature difference is greater than the frost-free temperature difference by 4.5 degrees or 5 degrees or other temperatures and is maintained for 1 minute, defrosting is started; when the frosting cumulative running time is not reached, but the actual temperature difference is greater than the frost-free temperature difference by 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 unintelligent and inaccurate frost layer judgment of the traditional time defrosting and constant value defrosting are solved, the defrosting method disclosed in the embodiment realizes the effect of defrosting when there is frost and not defrosting when there is no frost, improves the energy utilization rate, and avoids the problem of the evaporator 7 being blocked due to too thick frost layer.

[0085] In some embodiments, during the defrosting process, the high-pressure pressure value / compressor phase current value / intermediate coil temperature value is obtained and compared with the set value, and when the set value is exceeded, the control system 9 controls the DC fan 8 to draw air towards 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 intermediate coil temperature value detected by the intermediate coil temperature sensor 15 arranged on the distributor assembly 6, and compares the values with the set value to determine whether the system pressure is too high during defrosting in advance. When the value obtained by the control system 9 exceeds the set value, the DC fan 8 is started to draw air towards the upper part of the evaporator 7 to reduce 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 reaches the set temperature, the defrosting mode is exited, and the control system 9 controls the DC fan 8 to be turned off or to reduce the speed.

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

[0088] Preferably, in the embodiment, 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 and compares the value with the set value to control the DC fan 8 to draw air towards the evaporator 7.

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

[0090] Specifically, by adopting the above method, the problem that the system pressure is too high and forced protection shutdown occurs, resulting in the frost layer at the lower part of the evaporator 7 being unable to melt, can be avoided. By starting the DC fan 8 to reduce the temperature and pressure of the upper part of the evaporator 7, the defrosting time can be improved, the frost layer at the lower part of the evaporator 7 can be completely removed, and the situation that the frost layer at the lower part of the evaporator 7 is unable to melt is prevented, so that the defrosting is more frequent, which is beneficial to protecting the service life of the compressor 1 and the capacity efficiency of the air source heat pump.

[0091] According to the embodiment of the present application, the air source heat pump device is applied to the air source heat pump defrosting and defrosting method in the above embodiment, as shown in the figure, comprising: a compressor 1, a four-way reversing valve 2, an evaporator 7, a condenser 3, a direct current fan 8 and a control system 9. Figure 1 As shown in the figure, the compressor 1, the four-way reversing valve 2, the evaporator 7, the condenser 3, the direct current fan 8 and the control system 9 are connected.

[0092] Specifically, the compressor 1 is communicated with the evaporator 7 and the condenser 3 through the four-way reversing valve 2, the direct current fan 8 is arranged on one side of the evaporator 7, the environment temperature sensor 10 is arranged on the evaporator 7, and the environment temperature sensor 10 is connected with the control system 9 to transmit the detected environment temperature value to the control system 9. The low pressure pressure sensor 11 is arranged on the pipeline connected with the compressor 1, and the low pressure pressure sensor 11 is connected with the control system 9 to transmit the detected low pressure value to the control system 9. The water outlet temperature sensor 13 is arranged on the return water pipeline of the floor heating pipe 4 connected with the condenser 3, and the water outlet temperature sensor 13 is connected with the control system 9 to transmit the detected current water outlet temperature value to the control system 9. The control system 9 is electrically connected with the compressor 1 and the direct current fan 8, so that the control system 9 controls the frequency of the compressor 1 and the rotating speed of the direct current fan 8 according to the values transmitted by the environment temperature sensor 10, the low pressure pressure sensor 11 and the water outlet temperature sensor 13.

[0093] Specifically, as shown in the figure, the compressor 1 is communicated with the evaporator 7 and the condenser 3 through the four-way reversing valve 2. Figure 1 Specifically, as shown in the figure, the compressor 1 is communicated with the evaporator 7 and the condenser 3 through the four-way reversing valve 2. In the heating state, the compressor 1 delivers the high temperature and high pressure refrigerant to the condenser 3 through the four-way reversing valve 2, the condenser 3 is connected with the floor heating pipe 4, the high temperature and high pressure refrigerant exchanges heat with the water in the floor heating pipe 4 in the condenser 3, the throttling device 5 is arranged between the condenser 3 and the evaporator 7, the refrigerant in the condenser 3 exchanges heat and becomes low temperature and low pressure liquid through the throttling device 5, and then enters the evaporator 7 along the pipeline to exchange 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 heat exchanged refrigerant enters the compressor 1 again through the four-way reversing valve 2 to be compressed. The direct current fan 8 is arranged on one side of the evaporator 7. The direct current fan 8 can draw air to the evaporator 7 when the refrigerant exchanges heat in the evaporator 7, so as to improve the air flow speed, speed up the heat exchange process, take away the heat exchanged cold air, reduce the temperature difference outside the evaporator 7, and delay the rate of frosting. In the defrosting mode, the compressor 1 delivers the high temperature and high pressure refrigerant to the evaporator 7 through the four-way reversing valve 2. The high temperature and high pressure refrigerant enters the evaporator 7 to melt the frost layer on the surface of the evaporator 7, and then the refrigerant enters the compressor 1 again through the throttling device 5, the condenser 3 and the four-way reversing valve 2.

[0094] In the embodiment, the outer surface of the evaporator 7 is provided with an ambient temperature sensor 10, which can detect an ambient temperature value; the pipeline connected with the compressor 1 is provided with a low-pressure pressure sensor 11, which can detect a low-pressure pressure value of the air source heat pump; the return water pipeline of the condenser 3 and the floor heating pipe 4 is provided with a water outlet temperature sensor 13, which can detect a current water outlet temperature value in the floor heating pipe 4; the ambient temperature sensor 10, the low-pressure pressure sensor 11 and the water outlet temperature sensor 13 are respectively signal-connected with the control system 9, so as to transmit the detected ambient temperature value, low-pressure pressure value and current water outlet temperature value to the control system 9; the control system 9 sets the corresponding saturated temperature difference value of the ambient temperature value and the low-pressure pressure value as a frost-free temperature difference and an 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 judges according to the temperature difference between the target water outlet temperature and the current water outlet temperature; and the control system 9 controls the compressor 1 to reduce the frequency or increase the rotating speed of the direct-current fan 8 to delay the frost layer generation rate.

[0095] It should be noted that, by arranging 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 rotating speed of the direct-current fan 8 to delay the frost layer generation rate according to the data transmitted by the ambient temperature sensor 10, the low-pressure pressure sensor 11 and the water outlet temperature sensor 13 after processing, which is beneficial to reduce the defrosting frequency of the air source heat pump and help to improve the heat exchange efficiency of the air source heat pump.

[0096] In the embodiment, the distributor assembly 6 is arranged between the evaporator 7 and the compressor 1 and the throttling device 5; the compressor 1 is connected with 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; and 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, the fin temperature sensor 12 is arranged in the distributor assembly 6; the fin temperature sensor 12 is signal-connected with the control system 9; the fin temperature sensor 12 can transmit the detected fin temperature to the control system 9; the control system 9 sets the corresponding saturated temperature difference value of the ambient temperature value and the fin temperature value as a frost-free temperature difference and an 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 judges according to the temperature difference between the target water outlet temperature and the current water outlet temperature; and the control system 9 controls the compressor 1 to reduce the frequency or increase the rotating speed of the direct-current fan 8 to delay the frost layer generation rate.

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

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

[0100] like Figure 1 As shown, in some embodiments, a detection unit is also included. The detection unit is connected to the control system 9 and is adapted to acquire high-pressure values, compressor phase current values, and intermediate coil temperature values ​​and transmit them to the control system 9 so that the control system 9 can start / stop the DC fan 8 to draw air into the evaporator 7 based on the acquired 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 defrosting state, the control system 9 obtains the high pressure value detected by the detection unit and judges in advance whether the system pressure is too high during defrosting. When the value obtained by the control system 9 exceeds the set value, the DC fan 8 is started to draw air towards the evaporator 7 to reduce the temperature of the upper part of the evaporator 7, thereby 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 from the upper part of the evaporator 7, thereby reducing the temperature of the upper part of the evaporator 7 and thus reducing the pressure inside the evaporator 7.

[0103] 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 can determine in advance whether the system pressure is too high during defrosting based on the compressor phase current value, and control the first DC fan 801 to exhaust air from the upper part of the evaporator 7.

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

[0105] It should be noted that the detection unit can detect the high-pressure pressure value / compressor phase current value / intermediate coil temperature value at the same time, or detect any of the above values, and the control system 9 can determine according to any of the values to start the first direct current fan 801. Preferably, in the defrosting state, the control system 9 preferentially acquires the high-pressure pressure value.

[0106] As shown in Figure 1 In some embodiments, a partition 16 is arranged between the first direct current fan 801 and the second direct current fan 802.

[0107] In this embodiment, the partition 16 is arranged between the first direct current fan 801 and the second direct current fan 802, which can separate the first direct current fan 801 and the second direct current fan 802. In the defrosting state, the first direct current fan 801 draws air from the upper part of the evaporator 7, and the partition 16 can isolate the air drawn by the first direct current fan 801 to prevent the air drawn by the first direct current fan 801 from acting on the lower part of the evaporator 7, 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 / intermediate 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 direct current fan 801 to start drawing air towards the evaporator 7 to cool and depressurize the upper part of the evaporator 7, which can improve the defrosting time. At the same time, by arranging the partition 16, the air drawn by the first direct current fan 801 can be isolated to prevent the air drawn by the first direct current fan 801 from acting on the lower part of the evaporator 7, ensuring that the frost layer on the lower part of the evaporator 7 can be completely removed, preventing the frost layer on the lower part of the evaporator 7 from melting, making the defrosting more frequent, and protecting the service life of the compressor 1 and the capacity efficiency of the air source heat pump.

[0109] As shown in Figure 1 In some embodiments, the detection unit includes a high-pressure pressure sensor 14 and / or a compressor phase current detection module 902 and / or an intermediate 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 current detection module 902 is arranged in the control system 9, and the intermediate coil temperature sensor 15 is arranged on the distributor assembly 6. The high-pressure pressure sensor 14, the compressor phase current detection module 902, and the intermediate 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 intermediate coil temperature value to the control system 9.

[0111] It should be noted that in this embodiment, the high pressure sensor 14, the compressor phase current detection module 902, and the coil temperature sensor 15 are all installed in the air source heat pump. Preferably, in the defrosting state, the control system 9 first obtains the high pressure value detected by the high pressure sensor 14, and then 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 have only one or any two of the following: high pressure sensor 14, compressor phase current detection module 902, and 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 current detection module 902, and a fan power speed control board 903.

[0114] In this embodiment, the compressor phase current detection module 902 is mounted on the main control board 901. The main control board 901 is connected to the compressor 1, ambient temperature sensor 10, low pressure sensor 11, fin temperature sensor 12, outlet water temperature sensor 13, high pressure sensor 14, and intermediate coil temperature sensor 15. The ambient temperature sensor 10, low pressure sensor 11, fin temperature sensor 12, outlet water temperature sensor 13, high pressure sensor 14, and intermediate coil temperature sensor 15 can transmit the detected values ​​to the main control board 901. The main control board 901 is connected to the fan power speed control board 903. The fan power speed control board 903 is connected to the first DC fan 801 and the second DC fan 802. The main control board 901 is connected to the first DC fan 801 and the second DC fan 802 through the fan power speed control board 903. After judging and processing 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 embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for defrosting and controlling defrosting an air source heat pump, characterized in that, Includes the following steps: After the machine is turned on for heating, it automatically defrosts and records the difference between the ambient temperature and the saturation temperature corresponding to the low pressure during stable heating operation after defrosting. This is used as the frost-free temperature difference in the frost-free state. During the defrosting process, the high pressure value, compressor phase current value, and coil temperature value are obtained and compared with the set values. When the set value is exceeded, the DC fan (8) is controlled to draw air towards the evaporator (7). Then, the real-time ambient temperature and real-time low pressure are obtained, and the difference between the real-time ambient temperature and the low pressure corresponding to the saturation temperature 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 compressor (1) frequency or increases the DC fan (8) speed to delay the frost generation rate. When the cumulative frost time is reached, if the actual temperature difference is greater than the frost-free temperature difference and remains so, the control system (9) determines that there is frost and starts defrosting. The control system (9) controls the unit to start defrosting. If the cumulative frost time is not reached, if the actual temperature difference is greater than the frost-free temperature difference and remains so, the control system (9) determines that there is frost and starts defrosting.

2. The defrosting and defrosting method for an air source heat pump according to claim 1, characterized in that, Controlling the compressor (1) frequency or DC fan (8) speed to delay the frost formation rate 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 compressor (1) to keep the frequency unchanged and the DC fan (8) to increase the speed to delay the frosting rate. When the current outlet water temperature is lower than the target outlet water temperature and the current outlet water temperature is decreasing or maintaining a downward trend, the control system (9) controls the compressor (1) to keep the frequency unchanged and the DC fan (8) to increase the speed to delay the frosting rate. When the current outlet water temperature is lower than the target outlet water temperature and the current outlet water temperature is on the rise, the control system (9) controls the DC fan (8) to keep the wind speed unchanged and the compressor (1) to reduce the frequency in order to delay the frosting rate.

3. The defrosting and defrost control method for an air source heat pump according to claim 2, characterized in that, It also includes the following steps: After the compressor (1) frequency drops, the current outlet water temperature is checked each time and compared with the previous check record. If the current outlet water temperature changes from an upward trend to a sustained or downward trend, the compressor (1) frequency is stopped, and the speed of the DC fan (8) is increased or maintained for defrosting.

4. The defrosting and defrosting method for air source heat pumps 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, which can be used as the frost-free temperature difference in the frost-free state. In addition, the system acquires the real-time ambient temperature and the real-time fin temperature, and obtains the real-time difference between the ambient temperature and the fin temperature as the actual temperature difference.

5. An air source heat pump device, applied to the air source heat pump defrosting and de-frost control method according to any one of claims 1-4, comprising: The system comprises a compressor (1), a four-way reversing valve (2), an evaporator (7), a condenser (3), a DC fan (8), and a control system (9). 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 located on one side of the evaporator (7). Its features include: An ambient temperature sensor (10) is provided on the evaporator (7), 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 installed on the pipeline connecting the evaporator (7) and the compressor (1). The low-pressure sensor (11) is connected to the control system (9) to transmit the detected low-pressure value to the control system (9). A water outlet temperature sensor (13) is installed on the return water pipe of the condenser (3) and the floor heating pipe (4). The water outlet temperature sensor (13) is connected to the control system (9) to transmit the detected current water outlet 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 values ​​transmitted by the ambient temperature sensor (10), the low pressure sensor (11) and the outlet water temperature sensor (13).

6. The air source heat pump device according to claim 5, characterized in that, Also includes: The detection unit is connected to the control system (9). The detection unit is adapted to acquire the high pressure value / compressor phase current value / coil temperature value and transmit it to the control system (9) so that the control system (9) can start / stop the DC fan (8) to draw air towards the evaporator (7) according to the acquired data.

7. The air source heat pump device according to claim 6, characterized in that: The detection unit includes a high-pressure sensor (14) and / or a compressor phase current detection module (902) and / or a coil temperature sensor (15).

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