Disclosure of Invention
In order to solve the above problems in the prior art, that is, in order to more accurately judge the timing of entering the defrosting, the present invention provides a defrosting control method for an air conditioner, which comprises the following steps: detecting the temperature of the coil pipe of the outdoor unit under the condition that the air conditioner is in a heating working condition; acquiring an attenuation value of the temperature of the coil pipe of the outdoor unit every other first preset time; calculating the difference between the obtained attenuation values of the outdoor unit coil temperature; acquiring the relative humidity of the position of the outdoor unit; and judging whether the air conditioner enters a defrosting mode or not according to the difference between the attenuation values of the temperature of the coil pipe of the outdoor unit based on the relative humidity of the position of the outdoor unit.
In a preferred embodiment of the above defrosting control method for an air conditioner, "based on the relative humidity of the location of the outdoor unit, determining whether to enter the air conditioner into the defrosting mode according to the difference between the attenuation values of the temperatures of the coils of the outdoor unit" specifically includes: judging whether the relative humidity of the position of the outdoor unit is greater than a preset humidity threshold value, and if the relative humidity of the position of the outdoor unit is greater than the preset humidity threshold value, enabling the air conditioner to enter a defrosting mode if the difference value between the attenuation values of the temperatures of the coil pipes of the outdoor unit is greater than a first set threshold value, otherwise, not entering the defrosting mode; under the condition that the relative humidity of the position of the outdoor unit is not greater than the preset humidity threshold value, if the difference value between the attenuation values of the temperatures of the coil pipes of the outdoor unit is greater than a second set threshold value, enabling the air conditioner to enter a defrosting mode, otherwise, not entering the defrosting mode;
in a preferred embodiment of the above defrosting control method for an air conditioner, the preset humidity threshold is any value within 60% to 80%.
In a preferred embodiment of the above air conditioner defrosting control method, the first preset time is an arbitrary value within a range of 10 to 20 seconds.
In a preferred embodiment of the above defrosting control method for an air conditioner, the preset humidity threshold is 70%, and the first preset time is 15 seconds.
In a preferred embodiment of the above defrosting control method for an air conditioner, the second set threshold is greater than the first set threshold, and/or the first set threshold is 1 degree celsius and the second set threshold is 2 degrees celsius.
In a preferred embodiment of the above-mentioned defrosting control method for an air conditioner, the defrosting control method further includes a step of determining whether to exit the defrosting mode, the step including: after the air conditioner enters a defrosting mode, comparing the temperature of the coil of the outdoor unit with a third set threshold value; and judging whether to exit the defrosting mode or not according to the comparison result.
In a preferred embodiment of the above-mentioned defrosting control method of an air conditioner, the step of "determining whether to exit the defrosting mode according to the comparison result" further includes: under the condition that the temperature of the outdoor unit coil is greater than the third set threshold, judging whether the duration time of the state is greater than second preset time, and if the duration time of the state is greater than the second preset time, enabling the air conditioner to exit the defrosting mode; and if the duration time of the state is not more than the second preset time, enabling the air conditioner to maintain the defrosting working condition.
In a preferred embodiment of the above defrosting control method for an air conditioner, the third set threshold is an arbitrary value within a range of 6 to 10 degrees celsius; and/or the second preset time is any value within the range of 30-60 seconds.
In a preferred embodiment of the above defrosting control method for an air conditioner, the defrosting mode is a bypass defrosting mode in which a bypass branch is conducted to defrost a coil of an outdoor unit; and/or the step of "acquiring the relative humidity of the position where the outdoor unit is located" includes acquiring the relative humidity at the air outlet of the outdoor unit.
In the technical scheme of the invention, whether the air conditioner enters the defrosting mode is judged according to the difference value between the attenuation values of the temperature of the coil pipe of the outdoor unit based on the relative humidity of the position of the outdoor unit. In particular, the inventor has found that as the outdoor unit coil is frosted more and more, the temperature of the outdoor unit coil is greatly attenuated, and the attenuation is accelerated as the thickness of the frost layer is increased. Therefore, obtaining the difference between the attenuation values of the outdoor unit coil temperature is equivalent to obtaining the attenuation acceleration of the outdoor unit coil temperature, and compared with a simple attenuation value or attenuation speed, the frosting level of the outdoor unit coil can be more accurately judged through the attenuation acceleration. On the basis, the influence of the relative humidity on the frosting of the air conditioner is considered, namely when the relative humidity of the position of the outdoor unit is different, the frosting amount of the outdoor unit corresponding to the temperature attenuation speed of the coil pipe of the outdoor unit is also different, therefore, after the judgment condition of the relative humidity is added, when the defrosting time is judged to be entered by utilizing the difference value between the attenuation values of the temperature of the coil pipe of the outdoor unit, the defrosting time can be selected more accurately, and the false defrosting phenomenon is effectively avoided. In addition, when defrosting is carried out, the bypass defrosting mode is selected, so that the compressor is not stopped, the four-way valve is not reversed, the air conditioner continuously heats in the bypass defrosting process, the heating effect of the air conditioner can be greatly ensured, and the fluctuation of the indoor temperature is reduced to the maximum extent.
Detailed Description
Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and are not intended to limit the scope of the present invention. For example, although the steps of the method of the present invention are described herein in a particular order, these orders are not limiting, and one skilled in the art may perform the steps in a different order without departing from the underlying principles of the invention.
Based on the timing problem of entering defrosting provided in the background technology, the invention provides a defrosting control method of an air conditioner, aiming at enabling the air conditioner to enter a defrosting mode at a proper defrosting timing and avoiding the phenomena of false defrosting, excessive defrosting and the like, thereby reducing or even avoiding the phenomenon of reduction of the heating effect of the air conditioner caused by defrosting as much as possible.
Referring first to fig. 1, a schematic diagram of a conventional air conditioner is shown. As shown in fig. 1, the air conditioner mainly includes an outdoor unit 1, an indoor unit 2, a compressor 3, a four-way valve 4, and a throttle device 5. The structure of the air conditioner is well known to those skilled in the art and will not be described in detail herein.
Referring now to fig. 2, the defrost control method of the present invention includes the steps of: s110, detecting the temperature of the coil pipe of the outdoor unit under the condition that the air conditioner is in a heating working condition; s120, obtaining the attenuation value of the temperature of the coil pipe of the outdoor unit every first preset time; s130, calculating a difference value between the obtained attenuation values of the outdoor unit coil temperature; s140, acquiring the relative humidity of the position where the outdoor unit is located; and S150, judging whether the air conditioner enters a defrosting mode or not according to the difference value between the attenuation values of the temperature of the coil pipe of the outdoor unit based on the relative humidity of the position where the outdoor unit is located.
In the description of relative humidity, relative humidity means the ratio of the absolute humidity in the air to the saturated absolute humidity at the same temperature, and the figure is a percentage. (that is, the ratio of the mass of water vapor contained in a certain humid air to the mass of water vapor contained in saturated air at the same temperature, which is expressed in percentage). The relative humidity is expressed as RH. The relative humidity is defined as the percentage of the moisture density actually contained in a unit volume of air (represented by d 1) and the saturated moisture density at the same temperature (represented by d 2), i.e., RH (%) -d 1/d2x 100%; the other calculation method is as follows: the percentage of the actual air moisture pressure (denoted by p 1) and the saturated moisture pressure at the same temperature (denoted by p 2), i.e., RH (%) -p 1/p2x 100%. In this embodiment, a humidity sensor may be disposed on the outdoor unit to obtain the relative humidity of the location where the outdoor unit is located.
In the above steps S110 to S150, when determining whether to enable the air conditioner to enter the defrosting mode, first determining the relative humidity of the location of the outdoor unit, and then determining whether to defrost the coil of the outdoor unit according to the difference between the attenuation values of the temperature of the coil of the outdoor unit and the value of the relative humidity. Specifically, the inventor has found that, as the outdoor unit coil frosts more and more, the temperature of the outdoor unit coil is greatly attenuated as the outdoor unit coil frosts more and more, and the attenuation tends to be accelerated as the thickness of the frost layer increases. That is, as the thickness of the frost layer increases, the attenuation value of the outdoor unit coil within the preset time is increased, and thus, the degree of frosting of the outdoor unit can be accurately determined by determining the difference between the attenuation values of the outdoor unit coil temperature. On the basis, the influence of the relative humidity on the frosting of the air conditioner is considered, namely when the relative humidity of the position of the outdoor unit is different, the frosting amount of the outdoor unit corresponding to the temperature attenuation speed of the coil pipe of the outdoor unit is also different, therefore, after the judgment condition of the relative humidity is added, when the defrosting time is judged by utilizing the difference value between the temperature attenuation values of the coil pipe of the outdoor unit, the defrosting time can be selected more accurately, and the false defrosting phenomenon is effectively avoided. It can be understood by those skilled in the art that, on the premise of adding the relative humidity, if the air conditioner determines whether to defrost according to the attenuation speed, if the attenuation speed of the air conditioner at a certain moment reaches the time of entering the defrost due to the change of the air conditioner itself or the outside during the operation process, and then returns to normal again (i.e. the change of the attenuation speed at the moment belongs to the abnormal change), then the air conditioner is defrosted according to the attenuation speed at the moment, which may cause the false defrost phenomenon. If the condition occurs for a plurality of times during the operation of the air conditioner, frequent defrosting can be caused. In order to avoid the situation, the invention judges whether to defrost the coil pipe of the outdoor unit or not according to the difference value between the attenuation values of the temperature of the coil pipe of the outdoor unit on the premise of adding the relative humidity, and can accurately judge the frosting degree of the outdoor unit, thereby more accurately selecting the defrosting time and effectively avoiding the false defrosting phenomenon caused by instantaneous frosting.
The above steps S110 to S150 are described in further detail below.
In step S110, the outdoor unit coil temperature may be detected in real time by a temperature sensor disposed on the outdoor unit coil, or may be obtained by other known means, without departing from the scope of the present invention.
In step S120, the first preset time may be any value within a range of 10 to 20 seconds. For example, the first preset time may be set to 10 seconds, 15 seconds, 20 seconds, etc., and those skilled in the art may select an appropriate first preset time according to the actual application scenario. In a preferred embodiment of the present invention, the first predetermined time is 15 seconds, i.e., the temperature of the coil of the outdoor unit is acquired every 15 seconds. Then, the attenuation Δ T of the outdoor unit coil temperature within 15 seconds is Ti-Ti+1。
In step S130, the outdoor unit coil temperature Δ T that can be obtained within 30 seconds is obtained based on the attenuation value of the outdoor unit coil temperature obtained in step S1201And Δ T2. The difference N ═ Δ T1-ΔT2。
In step S140, a relative humidity value of a location where the outdoor unit is located is obtained by providing a humidity sensor on the outdoor unit. The relative humidity is expressed as HR. In this embodiment, the humidity sensor is disposed at the air outlet of the outdoor unit to obtain the relative humidity at the air outlet of the outdoor unit, and the relative humidity at the air outlet of the outdoor unit is used as a basis for determining the defrosting time.
In step S150, it is determined whether to put the air conditioner into the defrosting mode according to a difference between attenuation values of the outdoor unit coil temperature based on the relative humidity at the outdoor unit air outlet. For example, under the condition that the HR is larger than 70%, whether the difference value between the attenuation values of the coil temperature of the outdoor unit is larger than a first set threshold value or not is judged, and if the difference value between the attenuation values of the coil temperature of the outdoor unit is larger than the first set threshold value, the air conditioner enters a defrosting mode; if the difference value between the attenuation values of the outdoor unit coil temperature is not larger than the first set threshold value, the air conditioner is enabled to maintain the heating working condition and does not enter the defrosting mode. Preferably, the first set threshold is 1 degree celsius. Then, in this case (HR > 70%), when the difference between the attenuation values of the outdoor unit coil temperature is N ═ Δ T1-ΔT2And when the temperature is higher than 1 ℃, entering a defrosting mode. Otherwise, N is not more than 1 ℃, which indicates that the air conditioner is not yet availableThe optimal defrosting time is reached, so that the air conditioner maintains the heating working condition and does not enter the defrosting mode.
Under the condition that HR is less than or equal to 70%, judging whether the difference value between the attenuation values of the coil temperature of the outdoor unit is greater than a second set threshold value, and if the difference value between the attenuation values of the coil temperature of the outdoor unit is greater than the second set threshold value, enabling the air conditioner to enter a defrosting mode; if the difference value between the attenuation values of the outdoor unit coil temperature is not larger than the second set threshold value, the air conditioner is enabled to maintain the heating working condition and does not enter the defrosting mode. Preferably, the second set threshold is 2 degrees celsius. Then, in this case (HR > 70%), when the difference between the attenuation values of the outdoor unit coil temperature is N ═ Δ T1-ΔT2And when the temperature is higher than 2 ℃, entering a defrosting mode. Otherwise, if N is not more than 2 ℃, it indicates that the air conditioner has not reached the optimal defrosting time, so that the air conditioner maintains the heating working condition and does not enter the defrosting mode.
It should be noted that, although the first set threshold is 1 and the second set threshold is 2 in the above description, a person skilled in the art may set other suitable thresholds according to practical application scenarios, for example, the first set threshold is set to 1.5 degrees celsius, and the second set threshold is set to 2.5 degrees celsius, and so on. Since the setting of the first set threshold (HR > 70%) and the setting of the second set threshold (HR ≦ 70%) are both set according to the relative humidity, and when the relative humidity is high, frosting is relatively easy, the first set threshold is usually smaller than the second set threshold, thereby achieving the purpose of more accurately determining the timing for entering defrosting. In addition, the above value of the relative humidity may also be set according to a specific use scenario of the air conditioner.
In summary, the present invention detects the temperature of the outdoor unit coil and the relative humidity at the air outlet of the outdoor unit, and determines whether to enter the defrosting mode according to the difference between the attenuation values of the outdoor unit coil temperature based on the relative humidity. As outdoor unit coils frost more and more, the temperature of outdoor unit coils is greatly attenuated, and the attenuation tends to be accelerated as the thickness of frost layer increases. Therefore, compared with the rate of attenuation of the outdoor unit coil temperature (i.e., the attenuation value of the outdoor unit coil temperature within the preset time), the level of frosting of the outdoor unit coil can be more accurately determined by obtaining the difference between the attenuation values of the outdoor unit coil temperature. On the basis, the influence of the relative humidity on the frosting of the air conditioner is considered, namely when the relative humidity at the air outlet of the outdoor unit is different, the frosting amount of the outdoor unit corresponding to the temperature attenuation speed of the coil pipe of the outdoor unit is also different, therefore, after the judgment condition of the relative humidity is added, when the defrosting occasion is judged by utilizing the difference value between the temperature attenuation values of the coil pipe of the outdoor unit, the defrosting occasion can be selected more accurately, and the false defrosting phenomenon is effectively avoided. In addition, it should be noted that the first preset time, the first set threshold, and the second set threshold may be set according to an actual application scenario, or may be set by a user in a self-defined manner.
In addition, the control method of the invention also comprises a step of judging whether to exit the defrosting mode, and the step specifically comprises the following substeps: the method comprises the following steps: after the air conditioner enters a defrosting mode, comparing the temperature of the coil of the outdoor unit with a third set threshold value; and step two, judging whether to exit the defrosting mode or not according to the comparison result. The purpose of the first step and the second step is to determine the time for exiting defrosting. In the defrosting process, the heating effect of the air conditioner is reduced to a greater or lesser extent, so that the comfort of the indoor environment is affected. Therefore, the defrosting mode is exited at a proper time, and the defrosting time can be shortened as much as possible on the premise of ensuring the defrosting effect, so that the influence on the air conditioning heat effect is reduced.
Specifically, the third set threshold may be any value in the range of 6 to 10 degrees celsius. In a preferred embodiment of the invention, the third set threshold is 8 degrees celsius. In the defrosting mode, when the temperature Ti of the coil pipe of the outdoor unit is detected to be more than 8 ℃, whether the duration time of the state that the temperature Ti of the coil pipe of the outdoor unit is more than 8 reaches a second preset time is judged. The second preset time may be any value within the range of 30-60 seconds. In a preferred embodiment of the present invention, the second preset time is 40 seconds, and then when the outdoor unit coil temperature Ti > 8 continues for more than 40 seconds, it is determined that defrosting has been completed, and then defrosting is selected to be exited. And when the temperature Ti of the outdoor unit coil is not more than 8 or the temperature Ti of the outdoor unit coil is more than 8 but the duration time is not more than 40 seconds, judging that defrosting is not finished, and continuing the defrosting mode at the moment.
It should be noted that, in the above embodiment, although the condition for exiting the defrosting is that the outdoor unit coil temperature is greater than 8 degrees celsius and lasts for 40 seconds, a person skilled in the art may set the condition for exiting the defrosting to be another threshold value within the above range according to the actual application scenario, as long as the timing for exiting the defrosting can be accurately determined.
As described above, in the defrosting mode, whether to exit the defrosting mode is determined by comparing the detected outdoor unit coil temperature with the third set threshold. Because the temperature difference of the outdoor unit coil before and after frosting is larger, whether the defrosting is finished or not can be judged more accurately according to the temperature change of the outdoor unit coil, so that the defrosting time is shortened as much as possible on the premise of ensuring the defrosting effect, and the influence on the air conditioning heat effect is reduced. In addition, it should be noted that both the second preset time and the third preset threshold may be set according to an actual application scenario, or may be set by a user in a self-defined manner.
In a preferred embodiment, the air conditioner has a bypass branch, and the defrosting mode is a bypass defrosting mode for defrosting the coil of the outdoor unit by turning on the bypass branch. Specifically, referring to fig. 3, fig. 3 is a schematic structural diagram of an air conditioner according to an embodiment of the present invention. As shown in fig. 3, in this embodiment, the air conditioner mainly includes an outdoor unit 1, an indoor unit 2, a compressor 3, a four-way valve 4, a throttle device 5 (an electronic expansion valve in this embodiment), and a bypass branch 6 for communicating the compressor 3 and the outdoor unit 1, and the bypass branch 6 is provided with a one-way bypass valve, such as a solenoid valve 61. If the defrost condition is reached, a bypass defrost mode is entered. If the exit defrost condition is reached, the bypass defrost mode is exited. The following is a detailed description of the specific operation steps of the present invention with reference to fig. 4 on the basis of fig. 3.
Fig. 4 shows a detailed flow chart of the steps of a preferred embodiment of the defrost control method of the present invention. As shown in FIG. 4, inDetecting the temperature T of the coil pipe of the outdoor unit every 15 seconds under the heating running state of the air conditioneriAnd calculating the attenuation value delta T of the outdoor unit coil pipe temperaturei-Ti+1Two attenuation values DeltaT are obtained within 30 seconds1、ΔT2Then, the difference N ═ Δ T is calculated1-ΔT2。
And acquiring the relative humidity HR of the air outlet of the outdoor unit, and judging whether the HR is greater than 70%. And under the condition that the HR is more than 70%, judging whether N meets the condition: n is more than 1 degree centigrade. If the condition is met, entering bypass defrosting; if the condition is not satisfied, the defrost mode is not entered. And under the condition that the HR is not more than 70%, judging whether N meets the condition: n is more than 2 ℃. If the condition is met, entering bypass defrosting; if the condition is not satisfied, the defrost mode is not entered.
Specifically, when N satisfies the condition of entering defrosting, the air conditioner sends an opening control command to the solenoid valve 61, the solenoid valve 61 is opened, a part of the high-temperature and high-pressure refrigerant gas discharged by the compressor 3 enters the indoor unit 2 through the four-way valve 4 to continue heating, and the other part of the high-temperature and high-pressure refrigerant gas directly enters the outdoor unit 1 through the bypass branch 6. The high-temperature and high-pressure refrigerant gas can increase the temperature of the outdoor unit 1 in a short time to melt the frost. Therefore, in the bypass defrosting process, the compressor 3 is not stopped, the four-way valve 4 is not reversed, the air conditioner heats uninterruptedly, the heating effect of the air conditioner can be greatly ensured, and the fluctuation of the indoor temperature is small. And when the N does not meet the condition, the defrosting mode is not started until the N meets the condition, and then the defrosting mode is started.
With continued reference to FIG. 4, the temperature T of the outdoor unit coil is continuously sensed during the defrost processiAnd real-time judging outdoor unit coil temperature TiAnd if the temperature is higher than 8 ℃, and the temperature is maintained above 8 ℃ for 40 seconds, judging that the defrosting is finished, and selecting to quit the defrosting. If not, the defrosting is continued. When the defrosting is quitted, the air conditioner sends a closing control instruction to the electromagnetic valve 61, the electromagnetic valve 61 is closed, and all high-temperature and high-pressure refrigerant gas discharged by the compressor 3 enters the indoor unit 2 for heating through the four-way valve 4.
In order to shorten the defrosting time and improve the defrosting efficiency, the outdoor fan may be turned off to make most of the heat of the high-temperature and high-pressure refrigerant gas used for defrosting. And when the defrosting operation is quitted, the outdoor fan is turned on again.
Although the above embodiment has been described by taking bypass defrosting as an example, the defrosting control method of the present invention is not limited to a specific defrosting manner, and those skilled in the art can select an appropriate defrosting manner according to the specific structure of the air conditioner, for example, a reverse cycle defrosting manner, a combination of reverse cycle defrosting and bypass alternate defrosting, and the like. The invention aims to provide a method capable of more accurately judging defrosting entering and exiting opportunities.
So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.