Detailed Description
The following description and the drawings sufficiently illustrate specific embodiments of the invention to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. The examples merely typify possible variations. Individual components and functions are optional unless explicitly required, and the sequence of operations may vary. Portions and features of some embodiments may be included in or substituted for those of others. The scope of embodiments of the invention encompasses the full ambit of the claims, as well as all available equivalents of the claims. Embodiments may be referred to herein, individually or collectively, by the term "invention" merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed. Herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method or apparatus that comprises the element. The embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. As for the methods, products and the like disclosed by the embodiments, the description is simple because the methods correspond to the method parts disclosed by the embodiments, and the related parts can be referred to the method parts for description.
Fig. 1 is a schematic structural view of an air conditioner according to the present invention shown in an exemplary embodiment.
The invention provides an air conditioner which comprises an indoor heat exchanger 1, an outdoor heat exchanger 2, a throttling device 3 and a compressor 4, wherein the indoor heat exchanger 1, the outdoor heat exchanger 2, the throttling device 3 and the compressor 4 are connected through refrigerant pipelines to form a refrigerant circulation loop, and a refrigerant flows along flow directions set by different operation modes through the refrigerant circulation loop, so that the functions of heating, refrigerating, defrosting and the like are realized.
In the embodiment, the operation modes of the air conditioner comprise a refrigeration mode, a heating mode and a defrosting mode, wherein the refrigerant flow direction set during the operation of the refrigeration mode is that a high-temperature refrigerant discharged by a compressor 4 firstly flows through an outdoor heat exchanger 2 to exchange heat with the outdoor environment, then flows into an indoor heat exchanger 1 to exchange heat with the indoor environment, and finally the refrigerant flows back to the compressor 4 to be compressed again; in the process, the refrigerant flowing through the outdoor heat exchanger 2 emits heat to the outdoor environment, the refrigerant flowing through the indoor heat exchanger 1 absorbs heat from the indoor environment, and the indoor heat can be continuously discharged to the outdoor environment through the circulating flow of the refrigerant in the refrigerant circulating loop, so that the refrigeration purpose of reducing the temperature of the indoor environment can be achieved. The refrigerant flow direction set during the heating mode operation means that the high-temperature refrigerant discharged by the compressor 4 firstly flows through the indoor heat exchanger 1 to exchange heat with the outdoor environment, then flows into the outdoor heat exchanger 2 to exchange heat with the indoor environment, and finally flows back to the compressor 4 to be compressed again; in the process, the refrigerant flowing through the indoor heat exchanger 1 emits heat to the indoor environment, the refrigerant flowing through the outdoor heat exchanger 2 absorbs heat from the outdoor environment, and the outdoor heat can be continuously released to the indoor environment through the circulating flow of the refrigerant in the refrigerant circulating loop, so that the heating purpose of improving the temperature of the indoor environment can be achieved.
Under the condition that the air conditioner operates in a heating mode in winter severe cold weather or low-temperature weather, water vapor in the outdoor environment can be attached to the surface of the outdoor heat exchanger 2 of the outdoor unit and further can be condensed into frost or an ice layer, thus, the frost layer with a certain thickness can be formed on the outer surface of the outdoor heat exchanger 2, the outdoor heat exchanger 2 can be isolated from the air of the outdoor environment, the heat exchange quantity of a refrigerant in the outdoor heat exchanger 2 and the outdoor environment is reduced, and the heat release efficiency of the indoor unit to the indoor environment is further influenced. Therefore, under the condition that the frost layer is condensed on the outer surface of the outdoor heat exchanger 2, the air conditioner can carry out temperature rise operation on the outdoor heat exchanger 2 through the operation defrosting mode, so that the frost layer on the outer surface of the outdoor heat exchanger 2 can be heated and melted, and the defrosting purpose of eliminating the frost layer is achieved.
In the embodiment, the flow direction of the refrigerant in the defrosting mode in which the air conditioner operates to defrost the indoor heat exchanger is the same as the flow direction in which the air conditioner operates in the heating mode, and therefore, in the defrosting mode in which the air conditioner operates, the high-temperature refrigerant discharged from the discharge port 41 of the compressor 4 sequentially flows through the indoor heat exchanger 1, the throttle device 3, and the outdoor heat exchanger 2 in the flow direction corresponding to the heating mode, and then flows back to the return port 42 of the compressor 4. In this way, by increasing the flow opening of the expansion device 3, the high-temperature refrigerant in the portion of the indoor heat exchanger 1 that does not sufficiently release heat can flow into the outdoor heat exchanger 2, and heat can be released to the outside in the outdoor heat exchanger 2, so that the frost layer on the outer surface of the outdoor heat exchanger 2 can be melted by the heat released to the outside by the portion of the refrigerant.
In order to improve the defrosting efficiency of the outdoor heat exchanger 2, the air conditioner of the invention is further provided with a first pipeline 51 in the refrigerant circulation loop, wherein a first end of the first pipeline 51 is communicated with the exhaust port 41 of the compressor 4, and a second end of the first pipeline 51 is communicated with a first port 21 of the outdoor heat exchanger 2, which is connected with the indoor heat exchanger 1.
It should be understood that, when the air conditioner of the present invention operates in the defrosting mode, the refrigerant in the refrigerant circulation loop flows from the indoor heat exchanger 1 to the outdoor heat exchanger 2, and therefore, the first port 21 of the outdoor heat exchanger 2 connected to the indoor heat exchanger 1 is the liquid inlet end of the outdoor heat exchanger 2 when the air conditioner operates in the defrosting mode.
Thus, under the condition of conducting the first pipeline 51, a part of high-temperature refrigerant discharged from the exhaust port 41 of the compressor 4 continuously flows into the indoor heat exchanger 1 of the indoor unit along the refrigerant flow direction defined by the original refrigerant circulation loop, and the other part of high-temperature refrigerant directly flows into the outdoor heat exchanger 2 along the first pipeline 51, so that the refrigerant flow rate for defrosting the outdoor heat exchanger 2 during the defrosting mode of the air conditioner operation can be increased, and meanwhile, compared with the medium-high temperature refrigerant which flows out of the indoor heat exchanger 1 and has undergone one-time heat exchange, the temperature of the high-temperature refrigerant which directly flows into the outdoor heat exchanger 2 through the first pipeline 51 is higher, and the carried heat is more, so that the defrosting speed of the outdoor heat exchanger 2 can be increased, and the time for melting the frost layer on the outer surface of the outdoor heat exchanger 2 can be.
In addition, after the refrigerant flowing through the indoor heat exchanger 1 emits heat to the indoor environment according to the original refrigerant flowing direction, because the self heat is reduced and the temperature is reduced, part of the gaseous refrigerant can be liquefied into liquid refrigerant, and under the defrosting mode that the flow opening degree of the throttling device 3 is changed, the part of the liquid refrigerant can flow into the outdoor heat exchanger 2 along the refrigerant circulation loop and continuously flows back to the compressor 4 along the refrigerant circulation loop, thus causing the problems of liquid slugging and the like of the compressor 4, therefore, in order to reduce the amount of the liquid refrigerant flowing back to the compressor 4 and avoid the liquid slugging problem, the second end of the first pipeline 51 additionally arranged in the invention is communicated with the first port 21 of the indoor heat exchanger 1, so that the part of the liquid refrigerant flowing into the outdoor heat exchanger 2 from the indoor heat exchanger 1 can be mixed with the high-temperature refrigerant flowing into the indoor heat exchanger 1 from the first pipeline 51, therefore, the liquid refrigerant can be heated by the heat of the high-temperature refrigerant, so that the liquid refrigerant is heated and vaporized to be gaseous refrigerant, and the aim of reducing the amount of the liquid refrigerant flowing back to the compressor 4 is fulfilled.
In one embodiment of the present invention, the mixed refrigerant emits heat to the outside when passing through the outdoor heat exchanger 2, so that a frost layer on the outer surface of the outdoor heat exchanger 2 can be defrosted. The heat of the refrigerant after releasing heat is reduced, the temperature is reduced, and part of the refrigerant is liquefied into liquid refrigerant and continuously flows back to the compressor 4 along the refrigerant circulation loop. Therefore, in order to further reduce the amount of the liquid refrigerant flowing back to the compressor 4, the present invention further adds a second pipeline 52 in the refrigerant circulation loop, wherein a first end of the second pipeline 52 is communicated with the exhaust port 41 of the compressor 4, and a second end of the second pipeline 52 is communicated with the return port 42 of the compressor 4.
Thus, when the first pipeline 51 and the second pipeline 52 are both conducted, the high-temperature refrigerant discharged from the discharge port 41 of the compressor 4 includes a portion flowing to the outdoor heat exchanger 2 along the first pipeline 51 and a portion flowing to the indoor heat exchanger 1 along the refrigerant circulation loop in the foregoing embodiment, and also includes another portion flowing to the return port 42 of the compressor 4 along the second pipeline 52, and this portion of high-temperature refrigerant flows to the return port 42 of the compressor 4 through the second pipeline 52 and can be mixed with the low-temperature refrigerant returning to the return port 42 of the compressor 4 from the outdoor unit, so that the heat of the high-temperature refrigerant heats and raises the temperature of these low-temperature refrigerants, the mixed liquid refrigerant therein is heated and vaporized into a liquid refrigerant, and the purpose of reducing the amount of the liquid refrigerant returning to the return port 42 of the compressor 4 is achieved.
In order to simplify the pipeline connection structure of the air conditioner and reduce the number of pipe orifices connected with the exhaust pipeline of the compressor 4 and the length of the divided pipeline, the first pipeline 51 and the second pipeline 52 of the air conditioner are connected in parallel, so that the high-temperature refrigerant flows into one of the first pipeline 51 and the second pipeline 52 and then flows into the other pipeline.
Specifically, in one embodiment of the present invention, the first end of the first pipeline 51 is connected in parallel to the second pipeline 52, i.e. the second pipeline 52 is directly connected to the discharge pipeline of the compressor 4, and the first end of the first pipeline 51 is connected to the second pipeline 52. Thus, a part of the high-temperature refrigerant discharged from the discharge port 41 of the compressor 4 continuously flows into the indoor heat exchanger 1 along the refrigerant flow direction defined by the original refrigerant circulation circuit, another part of the high-temperature refrigerant flows into the second pipeline 52 from the first end of the second pipeline 52, and when the high-temperature refrigerant flows to the position where the first pipeline 51 is connected in parallel in the second pipeline 52, the part of the high-temperature refrigerant is divided again, and another part of the high-temperature refrigerant continuously flows along the second pipeline 52 and flows to the return air port 42 of the compressor 4, and another part of the high-temperature refrigerant is divided to the first pipeline 51 and flows to the outdoor heat exchanger 2 along the first pipeline 51.
Alternatively, the first end of the second pipeline 52 is connected in parallel to the first pipeline 51, that is, the first pipeline 51 is directly connected to the discharge pipeline of the compressor 4, and the first end of the second pipeline 52 is connected to the first pipeline 51. Thus, a part of the high-temperature refrigerant discharged from the discharge port 41 of the compressor 4 continuously flows into the indoor heat exchanger 1 along the refrigerant flow direction defined by the original refrigerant circulation circuit, another part of the high-temperature refrigerant flows into the first pipeline 51 from the first end of the first pipeline 51, and when the high-temperature refrigerant flows to the joint position of the second pipeline 52 in the first pipeline 51, the part of the high-temperature refrigerant is divided again, and a part of the high-temperature refrigerant continuously flows along the first pipeline 51 and flows to the outdoor heat exchanger 2, and another part of the high-temperature refrigerant is divided to the second pipeline 52 and flows to the return port 42 of the compressor 4 along the second pipeline 52.
In the embodiment, the throttling device 3 is connected to the refrigerant pipeline between the outdoor heat exchanger 2 and the indoor heat exchanger 1, and the second end of the first pipeline 51 of the invention is connected to the refrigerant pipeline section between the first end of the outdoor heat exchanger 2 and the throttling device 3, so that the high-temperature refrigerant flowing out of the first pipeline 51 is mixed with the refrigerant passing through the throttling device 3 and then flows into the outdoor heat exchanger 2. The advantage of this structure is that when the refrigerant flowing from the indoor heat exchanger 1 to the outdoor heat exchanger 2 flows through the throttling device 3, part of the gaseous refrigerant therein will be throttled into liquid refrigerant, therefore, in order to reduce the content of this part of liquid refrigerant, the second end of the second pipeline 52 is connected to the refrigerant pipeline section between the first end of the outdoor heat exchanger 2 and the throttling device 3, so that the temperature of the liquid refrigerant can be raised by the heat of the high-temperature refrigerant, and the liquid refrigerant is heated and vaporized into gaseous refrigerant.
In an embodiment, the first pipeline 51 is provided with a first control valve 61 for controlling the first pipeline 51 to be conducted or blocked, when the first control valve 61 is opened, the first pipeline 51 is in a conducting state, the high-temperature refrigerant discharged by the compressor 4 can flow to the outdoor heat exchanger 2 through the first pipeline 51, and when the first control valve 61 is closed, the first pipeline 51 is in a blocking state, the high-temperature refrigerant discharged by the compressor 4 cannot flow to the outdoor heat exchanger 2 through the first pipeline 51.
The second pipeline 52 is provided with a second control valve 62 for controlling the second pipeline 52 to be conducted or blocked, when the second control valve 62 is opened, the second pipeline 52 is in a conducting state, the high-temperature refrigerant discharged by the compressor 4 can flow to the return port 42 of the compressor 4 through the second pipeline 52, and when the second control valve 62 is closed, the second pipeline 52 is in a blocking state, the high-temperature refrigerant discharged by the compressor 4 cannot flow to the return port 42 of the compressor 4 through the second pipeline 52.
Meanwhile, the flow rate of the refrigerant flowing to the outdoor heat exchanger 2 and the return air port 42 of the compressor 4 may be adjusted by adjusting the flow rate openings of the first control valve 61 and the second control valve 62, respectively.
Fig. 2 is a flowchart illustrating a control method of an air conditioner according to the present invention, according to an exemplary embodiment.
The present invention provides a control method of the air conditioner, which can be applied to the defrosting operation control of the air conditioner shown in the foregoing embodiment, specifically, the control method includes:
s201, when the outdoor heat exchanger needs defrosting, the air conditioner operates in a defrosting mode;
in the embodiment, the conditions of the outdoor heat exchanger needing defrosting mainly include two types:
one is that after finding the frosting problem of the outdoor heat exchanger, the user inputs the defrosting instruction of the air conditioner through the remote controller or the control panel on the air conditioner body, thus, after the air conditioner receives the defrosting instruction input by the user, the air conditioner can be controlled to operate in the set defrosting mode;
the other is that the air conditioner automatically judges whether a set defrosting condition is reached, and when the set defrosting condition is met, the air conditioner can be controlled to operate in a defrosting mode, for example, the set defrosting condition is that the outdoor environment temperature is lower than an outdoor frosting critical temperature value under the current working condition, when the outdoor environment temperature is lower than the outdoor frosting critical temperature value, water vapor in the outdoor environment is gradually condensed to a frost layer on the outer surface of the outdoor heat exchanger, and the air conditioner needs to defrost the outdoor heat exchanger to avoid the excessive frost condensed on the outer surface of the outdoor heat exchanger
When the air conditioner operates in the defrosting mode, the flow direction of the refrigerant is the same as the flow direction of the refrigerant limited by the heating mode. Therefore, if the outdoor heat exchanger needs defrosting when the air conditioner is started to operate, the refrigerant of the air conditioner is controlled to flow in the same refrigerant flow direction as the heating mode; or, after the air conditioner operates in the heating mode for a certain time, the outdoor heat exchanger needs to be defrosted, and the flow direction of the refrigerant in the refrigerant circulation loop is kept unchanged.
S202, controlling to open a first control valve on the first pipeline and a second control valve on the second pipeline.
After the air conditioner operates in a defrosting mode, a first control valve on a first pipeline is opened, and a high-temperature refrigerant discharged by a compressor is introduced into an outdoor heat exchanger, so that frost condensed on the outdoor heat exchanger is melted, and the aim of defrosting and melting ice is fulfilled; the second control valve on the second pipeline is opened to guide the high-temperature refrigerant discharged by the compressor into the air return port of the compressor, so that the liquid refrigerant flowing back to the compressor is heated, heated and vaporized, the amount of the refrigerant condensed into liquid when flowing through the outdoor heat exchanger is reduced, and the safe and effective operation of the compressor and the whole air conditioner is ensured.
Specifically, the control method of the present invention further includes:
acquiring the return air temperature of a compressor when the air conditioner operates in a defrosting mode;
in an embodiment, the return air temperature of the compressor can reflect the real-time temperature of the refrigerant flowing back to the compressor, and if the return air temperature is different, the content of the liquid refrigerant mixed in the gas-liquid two-state refrigerant flowing back to the compressor is also different, so that the lower the return air temperature is, the higher the content of the liquid refrigerant is; the higher the return air temperature is, the lower the content of the liquid refrigerant is. Therefore, the flow rate of the high-temperature refrigerant for heating and vaporizing the liquid refrigerant can be determined according to the return air temperature when the air conditioner operates in the defrosting mode.
In an embodiment, a first temperature sensor is arranged at an air return port of the compressor and can be used for detecting the air return temperature of the compressor; it should be understood that the return air temperature is the temperature of the refrigerant flowing to the return air port of the compressor.
According to the return air temperature, the method is calculated according to the following formula:
K2=A+B*Ts+C*Ts2+D*Ts3,
wherein K2 is the second defrost flow opening, Ts is the return air temperature of the compressor, a is the first constant, B is the first calculation coefficient, C is the second calculation coefficient, and D is the third calculation coefficient.
For example, for an air conditioner with a heating capacity of 8KW, the following equation can be fitted by experimentally measuring values of the second defrost flow opening corresponding to Ts ═ 15 ℃, -10 ℃, -5 ℃, 0 ℃, and 5 ℃ before shipment of the air conditioner:
K2=177.6+-10.8*Ts-0.2*Ts2-0.097*Ts3,
wherein the first constant a is 177.6, the first calculated coefficient B is-10.8, the second calculated coefficient C is-0.2, and the third calculated coefficient D is-0.097.
Thus, the fitting formula can be preset in the air conditioner; in the actual working process of the air conditioner, the return air temperature Ts of the compressor is detected through the first temperature sensor, and the return air temperature Ts is substituted into the fitting formula, so that the second defrosting flow opening corresponding to the current working condition can be calculated.
Adjusting the flow opening of the second control valve to a second defrost flow opening; therefore, the high-temperature refrigerant quantity flowing to the return port of the compressor along the second pipeline can meet the refrigerant quantity required by the vaporized liquid refrigerant, the refrigerant can be completely carried out in the compressor in a gaseous form, and the liquid impact problem of the compressor is reduced.
In an embodiment, the exhaust port of the compressor is also provided with a temperature sensor, which can be used for detecting the exhaust temperature of the compressor, and the second defrosting flow opening degree can be further adjusted according to the exhaust temperature.
For example, the higher the exhaust temperature is, the more heat the high-temperature refrigerant of unit flow carries, the lower the second defrost flow opening may be controlled; the lower the exhaust temperature, the less heat the high temperature refrigerant carries per unit flow, and the higher the second defrost flow opening can be controlled. Therefore, the second defrosting flow opening is secondarily regulated according to the exhaust temperature of the compressor, so that the high-temperature refrigerant amount distributed to the second pipeline can be matched with the current working condition, and the redundant loss of the refrigerant heat is avoided.
In an embodiment, when the air conditioner operates in the defrosting mode, because the frost of the outdoor heat exchanger is gradually melted, the heat required by the outdoor heat exchanger for defrosting is gradually reduced, the heat emitted by the refrigerant flowing through the outdoor heat exchanger is also gradually reduced, and the return air temperature of the compressor is gradually increased in the defrosting stage.
Therefore, in order to avoid the additional consumption of the heat of the refrigerant, the control method of the invention further comprises the following steps:
when the air conditioner operates in a defrosting mode, if the return air temperature of the compressor is lower than a set return air temperature threshold value, controlling to gradually increase the flow opening of the first control valve at a set first time interval; specifically, when the air conditioner starts to operate in the defrosting mode, the first control valve is opened at an initial opening k, the first control valve is increased to an opening k1 after t1 minutes, the first control valve is increased to an opening k2 after t2 minutes, and the like until the maximum opening of the first control valve is reached, and in the process, if the condition that the return air temperature of the compressor is smaller than the set return air temperature threshold value is not met, the flow opening of the first control valve is stopped being continuously increased.
For example, under a certain working condition, the air conditioner is started to operate in a defrosting mode, the initial opening of the first control valve is 100B, the opening degree is increased to 200B after 1 minute, and the opening degree is increased to 350B after 3 minutes until the maximum opening degree is 500B; in this process, if the return air temperature of the compressor is not less than the set return air temperature threshold value after the 3 rd minute, the flow opening degree of the first control valve is stopped from being continuously increased from 350B.
And after the air conditioner operates in the defrosting mode for a certain time, if the return air temperature of the compressor is greater than or equal to the set return air temperature threshold value, controlling to gradually reduce the flow opening of the first control valve at set second time intervals. Specifically, when the air conditioner operates in the defrosting mode, the return air temperature within the time t2 is less than the set return air temperature threshold; after time t2, if the return air temperature is greater than or equal to the set return air temperature threshold, the opening degree of the first control valve is reduced to k3 after t3 minutes, the opening degree of the first control valve is reduced to k4 after t4 minutes, and the like until the first control valve is controlled to be closed.
For example, under the operating conditions of the foregoing embodiment, after the 3 rd minute, the return air temperature of the compressor is greater than or equal to the set return air temperature threshold, the opening degree at the 4 th minute is decreased from 350B to 300, after the 5 th minute, the valve opening degree 150B is opened, and then the defrosting is completed after the full closing.
Therefore, the flow opening of the first control valve is regulated in stages by taking time as an interval, the overall operation stability of the defrosting mode can be ensured, and the problems of turbulence, turbulent flow and the like in the pipeline caused by the too fast change of the flow and the flow speed in the refrigerant pipeline are prevented.
In an embodiment, the control method further comprises:
acquiring the liquid inlet temperature of the outdoor heat exchanger; in an embodiment, the refrigerant flowing direction in the defrosting mode of the air conditioner is the same as the refrigerant flowing direction in the heating mode, therefore, the first port is the liquid inlet port of the outdoor heat exchanger, and the detected liquid inlet temperature is the temperature of the refrigerant after the refrigerant flowing out from the second end of the first pipeline is mixed with the refrigerant flowing to the outdoor heat exchanger from the indoor heat exchanger.
In an embodiment, a third temperature sensor is arranged at the first port of the outdoor heat exchanger, and can be used for detecting the liquid inlet temperature of the outdoor heat exchanger.
Determining an outdoor dew point temperature of an outdoor environment; the outdoor dew point temperature is the critical temperature point of the liquid water condensed from the gaseous water in the outdoor environment, and when the outdoor environment temperature is lower than the outdoor dew point temperature, the liquid water condensed from the gaseous water in the outdoor environment is more in water quantity, and the water vapor liquefaction speed is higher; when the outdoor environment temperature is higher than the outdoor dew point temperature, the water amount of the gaseous water condensed into the liquid water in the outdoor environment is less, and the vaporization speed of the liquid water is higher.
Therefore, when the temperature of the refrigerant of the outdoor heat exchanger is lower than the outdoor dew point temperature, the refrigerant releases heat from the outdoor heat exchanger, so that after the air around the outdoor heat exchanger absorbs the heat released by the refrigerant, the air temperature is always lower than the self temperature of the refrigerant, namely the air temperature is also lower than the outdoor dew point temperature, and the outdoor environment temperature on the peripheral side of the outdoor heat exchanger also reaches the temperature condition of condensing ice and frost. Thus, in the control method of the invention, whether the frosting problem exists on the outer surface of the outdoor heat exchanger can be judged by comparing the outdoor dew point temperature with the refrigerant temperature.
In an embodiment, a fourth temperature sensor is disposed on the outdoor unit, and may be configured to detect an outdoor ambient temperature, so as to calculate and determine an outdoor dew point temperature according to the outdoor ambient temperature.
Specifically, the outdoor dew point temperature is calculated according to the following formula:
Tes=A*Tao2+B*Tao-C,
wherein Tes is the outdoor dew point temperature, Tao is the outdoor environment temperature, A is the first dew point temperature coefficient, B is the second dew point temperature coefficient, and C is the second constant.
If the liquid inlet temperature is lower than the outdoor dew point temperature, determining a third defrosting flow opening of a throttling device of the air conditioner according to the return air temperature;
specifically, determining a third defrost flow opening of a throttling device of the air conditioner according to the return air temperature includes:
if Tes is more than or equal to Te and more than or equal to Tes-D, the third defrosting flow opening is calculated according to the following formula:
K3=E*Tc+F,
wherein Te is a liquid inlet temperature, Tc is a return air temperature, D is a temperature deviation threshold value, K3 is a third defrosting flow opening, E is an opening calculation coefficient, and F is a third constant;
and if Te is less than Tes-D, the third defrosting flow opening is the maximum opening of the throttling device.
And taking the third defrosting flow opening as the flow opening of the throttling device when the air conditioner operates in the defrosting mode.
Fig. 3 is another flow chart illustrating a control method of the present invention according to an exemplary embodiment.
In the application scenario shown in fig. 3, the control method of the present invention has the following working flows:
s301, when the outdoor heat exchanger needs defrosting, the air conditioner operates in a defrosting mode;
in the embodiment, when a defrosting instruction input by a user is received or when the air conditioner self-checks that a set defrosting condition is met, the air conditioner is controlled to operate in a defrosting mode;
s302, controlling to open a first control valve and a second control valve;
s303, acquiring the return air temperature of the compressor when the air conditioner operates in a defrosting mode;
s304, determining a second defrosting flow opening of a second control valve according to the return air temperature;
in an embodiment, the flow opening of the second control valve is calculated according to the following formula:
K2=A+B*Ts+C*Ts2+D*Ts3,
wherein K2 is the second defrost flow opening, Ts is the return air temperature of the compressor, a is the first constant, B is the first calculation coefficient, C is the second calculation coefficient, and D is the third calculation coefficient.
S305, opening a second control valve, and adjusting the flow opening of the second control valve to a second defrosting flow;
s306, judging whether the return air temperature of the compressor is smaller than a set return air temperature threshold value, if so, executing a step S307, and if not, executing a step 308;
s307, controlling to gradually increase the flow opening of the first control valve at a set first time interval;
s308, controlling to gradually reduce the flow opening of the first control valve at a set second time interval;
s309, acquiring the liquid inlet temperature of the outdoor heat exchanger and the outdoor environment temperature;
s310, determining the outdoor dew point temperature of the outdoor environment according to the outdoor environment temperature;
in an embodiment, the outdoor dew point temperature is calculated according to the following formula: tes ═ a Tao2+ B and Tao-C, wherein Tes is outdoor dew point temperature, Tao is outdoor environment temperature, A is a first dew point temperature coefficient, B is a second dew point temperature coefficient, and C is a second constant;
s311, judging whether the liquid inlet temperature is lower than the outdoor dew point temperature, if so, executing a step S312, and if not, executing a step S314;
s312, determining a third defrosting flow opening of a throttling device of the air conditioner according to the return air temperature;
specifically, if Tes is more than or equal to Te is more than or equal to Tes-D, the third defrosting flow opening is calculated according to the following formula: k3 ═ E × Tc + F, where Te is the feed-in temperature, Tc is the return-air temperature, D is the temperature deviation threshold, K3 is the third defrost flow opening, E is the opening calculation coefficient, and F is the third constant;
if Te is less than Tes-D, the third defrosting flow opening is the maximum opening of the throttling device;
s313, taking the third defrosting flow opening as the flow opening of the throttling device when the air conditioner operates in the defrosting mode;
and S314, keeping the flow opening of the throttling device unchanged.
The invention also provides a control device, which can be used for controlling the flow of the refrigerant when the air conditioner shown in the embodiment of fig. 1 defrosts the outdoor heat exchanger, and the control device mainly comprises:
the first control unit is used for operating the air conditioner in a defrosting mode when the outdoor heat exchanger needs defrosting;
and the second control unit is used for controlling the opening of the first control valve on the first pipeline and the second control valve on the second pipeline.
In an embodiment, the control device further comprises: the first acquisition unit is used for acquiring the return air temperature of the compressor when the air conditioner operates in a defrosting mode; the first determining unit is used for determining a second defrosting flow opening of the second control valve according to the return air temperature; and the first adjusting unit is used for adjusting the flow opening of the second control valve to a second defrosting flow opening.
In an embodiment, the flow opening of the second control valve is calculated according to the following formula: k2 ═ a + B ═ Ts + C ═ Ts2+D*Ts3Where K2 is the second defrost flow opening, Ts is the return air temperature of the compressor, a is the first constant, B is the first calculation coefficient, C is the second calculation coefficient, and D is the third calculation coefficient.
In an embodiment, the control device further comprises a second adjusting unit for: when the air conditioner operates in a defrosting mode, if the return air temperature of the compressor is lower than a set return air temperature threshold value, controlling to gradually increase the flow opening of the first control valve at a set first time interval; and if the return air temperature of the compressor is greater than or equal to the set return air temperature threshold value, controlling to gradually reduce the flow opening of the first control valve at set second time intervals.
In an embodiment, the control device further comprises: the second acquisition unit is used for acquiring the liquid inlet temperature of the outdoor heat exchanger; a second determination unit for determining an outdoor dew point temperature of an outdoor environment; the third determining unit is used for determining a third defrosting flow opening of a throttling device of the air conditioner according to the return air temperature if the liquid inlet temperature is lower than the outdoor dew point temperature; and a second adjusting unit for setting the third defrosting flow opening as the flow opening of the throttling device when the air conditioner operates in the defrosting mode.
In an embodiment, the control device further comprises: a third acquiring unit for acquiring an outdoor environment temperature of an outdoor environment; a fourth determining unit for determining an outdoor dew point temperature of the outdoor environment according to the outdoor environment temperature; the outdoor dew point temperature is calculated according to the following formula: tes ═ a Tao2+ B and Tao-C, wherein Tes is outdoor dew point temperature, Tao is outdoor environment temperature, A is first dew point temperature coefficient, B is second dew point temperature coefficient, and C is second constant.
In an embodiment, the third determination unit determines a third defrost flow opening of a throttle device of the air conditioner according to the return air temperature, which includes: if Tes is more than or equal to Te and more than or equal to Tes-D, the third defrosting flow opening is calculated according to the following formula: k3 ═ E × Tc + F, where Te is the feed-in temperature, Tc is the return-air temperature, D is the temperature deviation threshold, K3 is the third defrost flow opening, E is the opening calculation coefficient, and F is the third constant; and if Te is less than Tes-D, the third defrosting flow opening is the maximum opening of the throttling device.
It is to be understood that the present invention is not limited to the procedures and structures described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.