Disclosure of Invention
The invention solves the technical problem that the air conditioner fails to collect liquid because the exhaust pressure of the compressor is overlarge in the liquid collecting process.
In order to solve the problems, the invention provides a liquid receiving control method of an air conditioner, wherein the air conditioner comprises a liquid receiving system, and the air conditioner comprises an outdoor machine heat exchanger, an indoor machine heat exchanger, a compressor, a liquid pipe and a throttling assembly; the liquid pipe is arranged between the outdoor unit heat exchanger and the indoor unit heat exchanger, the throttling assembly is arranged on the liquid pipe, and the liquid receiving control method comprises the following steps: the air conditioner operates in a refrigeration mode, and if liquid is collected, the operating frequency of the compressor is reduced; and detecting the return air pressure of the compressor, and controlling the corresponding mode of the air conditioner to operate according to the return air pressure.
Compared with the prior art, the technical scheme has the following technical effects: the air conditioner is controlled to operate in a corresponding mode according to the specific state of the return air pressure, so that the return air pressure can be stably changed, the connection between the liquid pipe and the outdoor unit heat exchanger is directly cut off, the exhaust pressure is increased at a highest speed, a high-pressure protection measure of the air conditioner is triggered, the compressor is stopped, and the liquid collection is failed.
In one example of the present invention, the controlling of the air conditioner to operate in the corresponding mode according to the return air pressure includes: judging whether the return air pressure meets a liquid collecting condition, if so, controlling the air conditioner to operate a liquid collecting mode; if not, controlling the air conditioner to run in the adjusting mode.
Compared with the prior art, the technical scheme has the following technical effects: the liquid collecting operation of the air conditioner is further ensured to be carried out smoothly, so that all the refrigerant in the heat exchanger and the return air pipeline of the indoor unit is collected into the compressor, the compressor can operate stably in the liquid collecting process, the liquid collecting efficiency is improved, and the waste of the refrigerant is avoided.
In one embodiment of the present invention, the liquid collecting conditions include: the return air pressure is less than or equal to the target return air pressure.
Compared with the prior art, the technical effect achieved by adopting the technical scheme is as follows: and correspondingly setting the liquid collecting condition by combining with the actual operation condition, wherein the setting of the liquid collecting condition is used for indicating that the refrigerant on the air return pipeline of the air conditioner is completely absorbed by the compressor at the moment, so that the air return pressure on the air return pipeline is stably changed under the suction action of the compressor due to the small amount of the refrigerant remained in the heat exchanger of the indoor unit when the liquid collecting mode is subsequently operated, and the air conditioner is further ensured to smoothly complete the liquid collecting operation so as to improve the liquid collecting efficiency.
In one example of the present invention, the adjustment mode includes: controlling to reduce the opening degree of the throttling component; and controlling the compressor to continuously operate, detecting the return air pressure at intervals of a first preset time T1, and judging whether the return air pressure is less than or equal to a target return air pressure.
Compared with the prior art, the technical scheme has the following technical effects: the liquid collecting mode is convenient for subsequent operation, and the liquid collecting efficiency is improved.
In one example of the present invention, the adjusting mode includes adjusting an opening degree of the throttling assembly, and the following formula is installed for adjustment: Δ PMV = Ka (P) s -P k )+Kb(P k-1 -P k ) (ii) a Wherein Δ PMV corresponds to a percentage change, P, of an initial opening of the throttling assembly s Is the target return air pressure, P k Return air pressure, P, detected for the k-th detection period k-1 Ka and Kb are constant values for the return air pressure detected in the k-1 th detection period.
Compared with the prior art, the technical scheme has the following technical effects: through fine control of the opening of the throttling assembly, the return air pressure can be stably reduced to the target return air pressure, and the air conditioner can smoothly complete liquid collection operation.
In one example of the invention, when the return air pressure is less than or equal to the target return air pressure, the throttling component is closed, and the liquid collecting mode is entered.
Compared with the prior art, the technical effect achieved by adopting the technical scheme is as follows: further, it is ensured that in the liquid collection mode, all the refrigerant in the indoor unit heat exchanger can be collected into the compressor.
In an example of the present invention, the controlling the air conditioner to operate the liquid receiving mode includes: acquiring the inlet air temperature and the outlet air temperature of the indoor unit heat exchanger and acquiring the temperature difference between the inlet air temperature and the outlet air temperature; the temperature difference is delta t, the air inlet temperature is ta, the air outlet temperature is to, and delta t = ta-to; judging whether the temperature difference meets a stop condition; if yes, controlling to close an air return pipeline arranged between the compressor and the indoor unit heat exchanger.
Compared with the prior art, the technical scheme has the following technical effects: and whether the refrigerant completely receives liquid into the compressor is further judged by utilizing the temperature difference, namely, a method for detecting whether the refrigerant completely receives liquid is optimized, and in addition, the refrigerant in the compressor is prevented from flowing back into the heat exchanger of the indoor unit by closing the gas return pipeline, so that the liquid receiving efficiency is improved.
In one example of the present invention, the stop condition includes: t1 is more than or equal to delta t is less than or equal to t2; wherein t1 and t2 are temperature thresholds.
In an example of the present invention, if the temperature difference satisfies a stop condition, controlling the compressor to operate for a third preset time T3; and controlling to close the air return pipeline.
Compared with the prior art, the technical scheme has the following technical effects: and the refrigerant left in the heat exchanger of the indoor unit is given enough time to return to the compressor, so that the liquid is completely collected without refilling the refrigerant.
In another aspect, the present invention further provides a control system for an air conditioner, the control system executing the liquid receiving control system according to any one of the above embodiments, the control system comprising: the detection module is used for detecting the return air pressure of the compressor; and the control module is used for controlling the corresponding operation mode of the air conditioner according to the return air pressure.
In another aspect, the present invention further provides an air conditioner, wherein the air conditioner performs the liquid collection control method according to any one of the above embodiments.
In one example of the present invention, includes: and the electromagnetic valve is arranged on an air return pipeline between the indoor unit heat exchanger and the compressor.
Compared with the prior art, the technical scheme has the following technical effects: and under the condition of combining the actual liquid collection, the characteristic that the electromagnetic valve can be closed in a delayed manner is utilized, so that the refrigerant is further ensured to be completely collected into the compressor.
After the technical scheme of the invention is adopted, the following technical effects can be achieved:
(1) Controlling the air conditioner to operate in a corresponding mode according to the specific state of the return air pressure so that the return air pressure can be changed stably, directly cutting off the connection between the liquid pipe and the outdoor unit heat exchanger to cause the exhaust pressure to rise at a highest speed, triggering a high-pressure protection measure of the air conditioner to stop the compressor and cause the liquid collection to fail;
(2) The temperature difference formed by the air outlet temperature and the air inlet temperature of the indoor unit heat exchanger is utilized to further judge whether the refrigerant is completely absorbed by the compressor, namely, a method for detecting whether the refrigerant quantity completely receives liquid is optimized, and the liquid receiving efficiency is improved;
(3) After the liquid collecting operation is finished, the gas return pipeline is in a closed state, the refrigerant is prevented from flowing back into the heat exchanger of the indoor unit from the compressor, the liquid is completely collected, and the refrigerant does not need to be refilled.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
The first embodiment is as follows:
referring to fig. 1, a flow chart of a liquid collection control method of an air conditioner according to an embodiment of the present invention is schematically shown. Referring to fig. 2 to 3, the air conditioner 100 includes a liquid receiving system, and the air conditioner 100 includes an indoor heat exchanger 10, an outdoor heat exchanger 20, a compressor 30, a liquid pipe 41, and a throttling assembly 42. The liquid pipe 41 is arranged between the outdoor heat exchanger 20 and the indoor heat exchanger 10; a throttle assembly 42 is provided on the liquid pipe 41.
In one particular embodiment, the air conditioner 100 further includes, for example, a discharge line 44, a return line 43, and a four-way valve 48. A discharge line 44 connected between a discharge port of the compressor 30 and the outdoor unit heat exchanger 20; the return air pipeline 43 is arranged between the air inlet of the compressor 30 and the indoor heat exchanger 10; a four-way valve 48 is used to connect the return air line 43 and the exhaust air line 44. A liquid pipe stop valve 45 is further provided on the liquid pipe 41, and an air pipe stop valve 46 is further provided on the air return pipe 43. For example, when the air conditioner 100 operates in a cooling mode, the compressor 30 discharges high-temperature and high-pressure refrigerant gas from the exhaust port onto the exhaust pipe 44, the high-temperature and high-pressure refrigerant gas enters the outdoor heat exchanger 20 through the reversing action of the four-way valve 48, the high-temperature and high-pressure refrigerant gas is converted into medium-temperature refrigerant liquid through the heat releasing and condensing action of the outdoor heat exchanger 20, the medium-temperature refrigerant liquid is conveyed into the indoor heat exchanger 10 through the liquid pipe 41, the medium-temperature refrigerant liquid is converted into low-temperature and low-pressure refrigerant gas through the evaporation and heat absorption action, and the low-temperature and low-pressure refrigerant gas is conveyed into the compressor 30 through the air inlet via the air return pipe 43 through the reversing action of the four-way valve 48, so that the circulation action of the refrigerant in the cooling mode is completed. A first pressure sensor is arranged on the return air line 43, and is used for detecting the return air pressure, and a second pressure sensor is arranged on the exhaust line 44, and is used for detecting the exhaust pressure.
Specifically, the liquid collection control method includes:
s1: when the air conditioner 100 operates in the cooling mode and receives the liquid, the operating frequency of the compressor 30 is reduced.
S2: the return air pressure of the compressor 30 is detected, and the corresponding mode of operation of the air conditioner 100 is controlled according to the return air pressure.
In one embodiment, the prior art liquid collection operation is: the air conditioner 100 operates at a normal frequency, for example, in a 50Hz state, when the air conditioner 100 receives a liquid receiving command, the liquid pipe stop valve 45 disposed on the liquid pipe 41 is directly closed, that is, the refrigerant pipeline of the outdoor heat exchanger 20 is closed, at this time, the refrigerant circulation of the entire air conditioning system is cut off, and since the compressor 30 is still in an operating state at this time, the refrigerant in the indoor heat exchanger 10, the air return pipeline 43, and the air pipe stop valve 46 can still be sucked by the compressor 30, and is discharged from the air outlet after the compression in the compressor 30 is completed, so that the discharge pressure in the discharge pipeline 44 is continuously increased. In this case, when the liquid receiving operation is performed on the refrigerant, the refrigerant is not completely recovered into the compressor 30, and the discharge pressure exceeds a safety threshold, so that a high-pressure protection measure of the air conditioner system is triggered, and the compressor 30 is stopped. This shutdown can result in a failure to collect the liquid, causing significant disruption to the removal or maintenance of the indoor unit.
Referring to fig. 3, as an improvement, in combination with the technical solution of the present invention, the air conditioner 100 is started and is adjusted to enter the cooling mode, when a liquid receiving instruction is received, the operating frequency of the compressor 30 is reduced, and further, the discharge pressure on the discharge line 44 is reduced, the corresponding mode that the air conditioner 100 enters is controlled according to the return air pressure, for example, the opening degree of the throttling assembly 42 is controlled to be gradually reduced, that is, the amount of refrigerant passing through the return air line 43 is gradually reduced, that is, the return air pressure is slowly changed, and since the refrigerant can still circulate, the discharge pressure is also slowly changed, so as to ensure that the compressor can complete the liquid receiving operation. In the prior art, the liquid pipe stop valve 45 is directly closed, so that the suction force of the compressor 30 causes the return pressure on the return gas pipeline 43 to be extremely reduced, the discharge pressure on the discharge pipeline 44 to be extremely increased, the discharge pressure exceeds a safety threshold value, and high-pressure protection measures of the air conditioner system are triggered, so that the compressor 30 is stopped, and the liquid collection is failed.
Specifically, after the air conditioner 100 operates in the cooling mode, the compressor 30 is operated at a frequency of 20Hz for a time T0 to ensure that the air conditioner 100 enters a steady state, where T0 may take 60 seconds, for example, and at this time, the throttle assembly 45 maintains an initial opening degree of 200pls, for example.
Further, the corresponding modes for controlling the air conditioner 100 to operate according to the return air pressure include:
judging whether the return air pressure meets a liquid collecting condition, if so, controlling the air conditioner 100 to operate a liquid collecting mode;
if not, the air conditioner 100 is controlled to operate the adjusting mode.
Further, the liquid receiving conditions comprise: the return air pressure is less than or equal to the target return air pressure.
Specifically, the adjustment mode includes:
controlling to decrease the opening of the throttle assembly 42;
and controlling the compressor 30 to continuously operate, detecting the return air pressure at intervals of a first preset time T1, and judging whether the return air pressure is less than or equal to the target return air pressure. In short, the return air pressure is periodically detected so as to timely know the change of the return air pressure in the return air pipeline 43, and then the opening of the throttling component 42 is adjusted according to the return air pressure. For example, T1 may be 1 second, that is, the return air pressure is detected after the compressor 30 operates for 1 second, and if the return air pressure is still greater than the target return air pressure, the opening degree of the throttling element 42 is continuously decreased, so that the compressor 30 operates for 1 second again, and the above process is repeated until the return air pressure is less than or equal to the target return air pressure.
Specifically, the amount of the refrigerant remaining in the return pipe 43 is reflected by the return pressure, and when the return pressure in the return pipe 43 is less than or equal to the target return pressure, the amount of the refrigerant in the return pipe 43 is considered to be completely absorbed by the compressor 30.
It should be noted that, in an ideal state, when there is no refrigerant in the return air pipe 43, the return air pressure is zero, but in an actual equipment operation process, it is difficult to completely evacuate, and normally, when the vacuum degree of the outdoor unit is generally evacuated to 0.005Mpa, it can be considered that the outdoor unit is in a completely evacuated state, that is, when the return air pressure in the return air pipe 43 is 0.005Mpa, it can be considered that there is no refrigerant in the return air pipe 43. In the present embodiment, for example, the target return air pressure may be 0.01Mpa.
In one embodiment, in the adjusting mode, by continuously adjusting the opening degree of the throttling assembly 42, for example, continuously decreasing the opening degree, so as to gradually decrease the corresponding return air pressure to the target return air pressure, the adjustment range of the opening degree can be changed smoothly every time during the process of adjusting the opening degree, so that the compressor 30 can smoothly perform the liquid collecting operation. The throttle assembly 42 may be, for example, an electronic expansion valve, and the control system inside the air conditioner 100 finely controls the valve step by step.
Preferably, the adjustment mode includes adjusting the opening of the throttling assembly 42 according to the following formula:
equation 1: Δ PMV = Ka (P) s -P k )+Kb(P k-1 -P k );
Wherein, the pair of Δ PMVThe percentage change amount, P, of the initial opening of the throttling assembly s Is the target return air pressure, P k Return air pressure, P, detected for the kth detection cycle k-1 Ka and Kb are constant values for the return air pressure detected in the k-1 th detection period.
For example, the initial valve step of the electronic expansion valve may be set to 200pls, ps =0.01mpa, pk =0.013mpa, pk-1=0015mpa, ka =10, kb =5, and then the above respective parameter values are substituted into the formula: Δ PMV = Ka (P) s -P k )+Kb(P k-1 -P k ) If Δ PMV = -0.02, that is, since Pk is still greater than Ps, the opening degree of the electronic expansion valve needs to be decreased by 2% again, that is, the opening degree is 196pls at this time. Thereby further reducing the return air pressure, so that the amount of the refrigerant passing through the return air pipe 43 is also correspondingly reduced until the return air pressure is less than or equal to the target return air pressure, that is, all the refrigerant in the return air pipe 43 is recycled into the compressor 30.
Of course, since the value of the return air pressure itself is small, if the influence of the return air pressure on the control of the electronic expansion valve is increased, that is, the percentage of change in the opening degree of the corresponding electronic expansion valve is increased, the values of Ka and Kb may be increased, and otherwise, the corresponding values of Ka and Kb may be decreased.
Preferably, when the return air pressure is less than or equal to the target return air pressure, the throttling assembly 42 is closed, and the liquid collecting mode is entered.
Preferably, the controlling the air conditioner 100 to operate the liquid receiving mode includes:
acquiring the inlet air temperature and the outlet air temperature of an indoor unit heat exchanger 10 and acquiring the temperature difference between the inlet air temperature and the outlet air temperature; wherein, Δ t = ta-to, Δ t is the temperature difference, ta is the air inlet temperature, and to is the air outlet temperature;
judging whether the temperature difference meets a stop condition; if so, the air return line 43 provided between the compressor 30 and the indoor unit heat exchanger 10 is controlled to be closed.
Further, the stop condition includes: t1 is more than or equal to delta t is less than or equal to t2; wherein t1 and t2 are temperature thresholds. Specifically, t1 may be 0 ℃ and t2 may be 0.2 ℃.
It should be noted that, when the external environment is high, so that the air conditioner 100 operates in the cooling mode, the heat exchange effect of the refrigerant is utilized, cold air with a low temperature is blown out from the indoor heat exchanger 10, warm air with a high temperature is sucked from the air inlet of the indoor heat exchanger, and when the throttling assembly 42 enters the closed state, the refrigerant quantity in the indoor heat exchanger 10 is continuously reduced along with the continuous operation of the compressor 30, that is, the cooling effect of the air conditioner 100 is gradually weakened, that is, the air outlet temperature is continuously increased and is drawn toward the air inlet temperature, and when the refrigerant quantity completely flows back into the compressor 30, the air outlet temperature is equal to the air inlet temperature at this time.
On the contrary, when Δ T is greater than 0.2 ℃, it means that there is still more refrigerant in the indoor heat exchanger 10, so that at every interval T4, the temperature difference is detected by using the temperature sensor, and the discharge pressure on the discharge pipe 44 exceeds the safety threshold due to long-term operation of the compressor 30 is avoided. Wherein T4 may be taken to be 2 seconds.
Preferably, when the air conditioner 100 enters the liquid receiving mode, the throttling assembly 42 may be in a closed state to prevent the refrigerant from flowing into the indoor heat exchanger 10, and particularly, a small amount of refrigerant exists in the indoor heat exchanger 10, at this time, the liquid pipe stop valve 45 may also be in a closed state to prevent the refrigerant from flowing from the outdoor heat exchanger 20 to the indoor heat exchanger 10, and since the compressor 30 is still in the running state, the temperature difference may be periodically detected by the temperature sensor at intervals of the second preset time T2, so as to timely adjust the running state of the compressor 30, for example, continuously run or shut down, so as to prevent the discharge pressure on the discharge pipe 44 from exceeding a safety threshold value and affecting the reliability of the air conditioning system in the long-term running state of the compressor 30.
In addition, since the amount of the refrigerant remaining in the indoor heat exchanger 10 is a small amount, the refrigerant is made to intermittently flow through the air return pipe 43, and therefore, preferably, when the temperature difference satisfies the stop condition, the compressor 30 is still controlled to operate for the third preset time T3, and then the compressor 30 is controlled to enter the shutdown state, so as to ensure that the refrigerant completely flows back into the compressor 30, and avoid that a part of the refrigerant is not timely flowed back into the compressor 30 and remains in the air return pipe 43, which causes waste of the amount of the refrigerant. Wherein, T3 may be 0.5 second.
Example two:
referring to fig. 4, a block diagram of a control system 200 of an air conditioner according to a second embodiment of the present invention is shown. It should be noted that the air conditioner in this embodiment is the same as the air conditioner 100 mentioned in the first embodiment, and the control system 200 can perform the liquid receiving control method described in the first embodiment.
Specifically, the control system 200 includes, for example, a regulation module 210, a detection module 220, and a control module 230. The adjusting module 210 is used for adjusting the operating frequency of the air conditioner 100; the detection module 220 is used for detecting the return air pressure of the compressor 30; the control module 230 controls the air conditioner 100 to operate in a corresponding mode according to the return air pressure.
Preferably, the detection module 220 further includes a temperature detection module, for example, the temperature detection module may be configured to detect an outlet air temperature and an inlet air temperature of the indoor unit heat exchanger, so as to obtain a temperature difference between the outlet air temperature and the inlet air temperature. In combination with the specific liquid collecting process, the control module 230 can accurately determine whether the refrigerant remaining in the indoor unit heat exchanger 10 completely flows back into the compressor 30 when controlling the throttling assembly 42 to enter the closed state.
Example three:
this embodiment provides an air conditioner, which can execute the liquid collection control method according to the first embodiment. Accordingly, the air conditioner can achieve any technical effect as in the first embodiment, and details are not repeated herein.
Preferably, the air conditioner includes, for example, a solenoid valve 47, and the solenoid valve 47 is provided in the return line 43 between the indoor unit heat exchanger 10 and the compressor 30. Because the electromagnetic valve 47 can be controlled to be opened or closed by a control module in the air conditioner, or be closed in a delayed manner, when the temperature detector detects that the outlet air temperature is equal to the inlet air temperature for the first time, the electromagnetic valve 47 is controlled to be closed in a delayed manner, for example, the electromagnetic valve is closed after the delay time is 0.5 second, so that the refrigerant can completely flow back into the compressor 30, and the loss of the refrigerant caused by misjudgment is avoided.
Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.