CN115654796A - Oil return control method and device and multi-split system - Google Patents
Oil return control method and device and multi-split system Download PDFInfo
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Abstract
The invention provides an oil return control method, an oil return control device and a multi-split system; wherein, the method comprises the following steps: acquiring the outlet temperature of the oil return capillary in real time; judging whether a refrigerant exists in the oil return capillary tube or not according to the outlet temperature and a preset temperature threshold; if so, performing current oil return control on the multi-split system; in the current oil return control, calculating to obtain the flow rate of the refrigerant according to the calculation parameters and a preset Flooding formula; calculating to obtain the corresponding oil return frequency of the compressor in the current oil return control according to the displacement and the volume coefficient of the compressor, the flow rate and the inner diameter of the piping; and controlling the compressor to operate according to the oil return frequency. In the oil return control mode, whether a refrigerant exists in the oil return capillary tube or not is intelligently judged according to the outlet temperature, current oil return control is carried out when the refrigerant exists, and the oil return frequency corresponding to the compressor is calculated according to the calculation parameters and a preset Flooding formula in the oil return control, so that the oil return reliability is ensured.
Description
Technical Field
The invention relates to the technical field of air conditioners, in particular to an oil return control method and device and a multi-split system.
Background
The oil return control technology is one of the key technologies of the multi-connected heat pump air conditioner, and is concerned with the operation reliability of the compressor. In the oil return process, due to the fact that the frequency of the compressor is improved and the opening degree of the electronic expansion valve of the internal machine is controlled when the internal machine is stopped, noise exists in the running process, and the comfort of the air conditioner is affected. The existing oil return control mainly takes the running time of an air conditioning unit as a judgment condition for judging whether to enter oil return or not, and adopts fixed oil return frequency in the oil return process, so that the compressor frequently returns oil, and the oil return effect is reduced. Therefore, how to ensure the oil return effect is a problem which needs to be solved urgently.
Disclosure of Invention
In view of the above, the present invention provides an oil return control method, an oil return control device and a multi-split system, so as to alleviate the above technical problems, ensure oil return reliability, and avoid energy loss and use comfort caused by excessive output of oil return frequency; meanwhile, oil return according to needs is realized, and the oil return frequency is reduced.
In a first aspect, an embodiment of the present invention provides an oil return control method, which is applied to a controller of a multi-split system, where the multi-split system further includes a compressor and an oil return capillary tube; the method comprises the following steps: acquiring the outlet temperature of the oil return capillary in real time; judging whether a refrigerant exists in the oil return capillary tube or not according to the outlet temperature and a preset temperature threshold; if so, performing current oil return control on the multi-split system; in the current oil return control, calculating to obtain the flow rate of the refrigerant according to the calculation parameters and a preset Flooding formula; wherein, calculating the parameters comprises: refrigerant density, oil density, gravity acceleration, correction coefficient and the inner diameter of a piping of a compressor air suction pipe; calculating to obtain the corresponding oil return frequency of the compressor in the current oil return control according to the displacement and the volume coefficient of the compressor, the flow rate and the inner diameter of the piping; and controlling the compressor to operate according to the oil return frequency.
According to the oil return control method, whether a refrigerant exists in the oil return capillary tube or not is intelligently judged according to the outlet temperature, when the refrigerant exists, namely the internal oil quantity of the compressor is insufficient, current oil return control is carried out, and the oil return frequency corresponding to the compressor is calculated according to the calculation parameters and the preset Flooding formula in the oil return control, so that the oil return reliability is ensured, and the energy loss and the use comfort caused by overlarge output of the oil return frequency are avoided; meanwhile, oil return is carried out when the oil quantity in the compressor is insufficient, oil return according to requirements is achieved, and therefore oil return frequency is reduced.
Preferably, the above method further comprises: acquiring the last interval duration of the multi-split system; the last interval duration is used for representing the interval duration from the time when the multi-split air conditioning system exits from the last oil return control to the time when the multi-split air conditioning system enters the current oil return control; judging whether the previous interval duration is greater than a preset interval threshold or not; if so, reducing and correcting the oil return frequency according to preset correction parameters, and controlling the compressor to operate according to the oil return frequency after the reducing and correcting.
Preferably, the method further comprises: and if the last interval duration is less than the preset interval threshold, increasing and correcting the oil return frequency according to preset correction parameters, and controlling the compressor to operate according to the increased and corrected oil return frequency.
Preferably, the method further comprises: and in the current oil return control, the running time of the compressor running according to the oil return frequency is obtained, and when the running time reaches the preset time, the multi-split air conditioner system is controlled to exit the current oil return control.
Preferably, the step of determining whether the refrigerant exists in the oil return capillary tube according to the outlet temperature and the preset temperature threshold includes: calculating a difference between a preset temperature threshold and an outlet temperature; judging whether the difference value is larger than a preset difference value threshold value or not; if yes, the refrigerant is judged to exist in the oil return capillary tube.
Preferably, the multi-split air-conditioning system further includes an outdoor electronic expansion valve and a plurality of indoor electronic expansion valves, and the method further includes: and in the current oil return control, adjusting the opening degree of the outdoor electronic expansion valve to a first oil return opening degree, and adjusting the opening degrees of the plurality of indoor electronic expansion valves to a second oil return opening degree.
Preferably, the first oil return opening degree is 200pls, and the second oil return opening degree is 250pls.
In a second aspect, an embodiment of the present invention further provides an oil return control device, which is applied to a controller of a multi-split system, where the multi-split system further includes a compressor and an oil return capillary tube; the device includes: the temperature acquisition module is used for acquiring the outlet temperature of the oil return capillary in real time; the refrigerant judgment module is used for judging whether a refrigerant exists in the oil return capillary tube or not according to the outlet temperature and a preset temperature threshold; the oil return control module is used for performing current oil return control on the multi-split air conditioner system if the current oil return control is positive; the flow rate calculation module is used for calculating the flow rate of the refrigerant according to the calculation parameters and a preset Flooding formula in the current oil return control; wherein, calculating the parameters comprises: refrigerant density, oil density, gravity acceleration, correction coefficient and the inner diameter of a piping of a compressor suction pipe; the frequency calculation module is used for calculating and obtaining the oil return frequency corresponding to the compressor in the current oil return control according to the displacement and the volume coefficient of the compressor, the flow rate and the inner diameter of the piping; and the operation control module is used for controlling the compressor to operate according to the oil return frequency.
In a third aspect, an embodiment of the present invention further provides a multi-split system, including a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor executes the computer program to implement the steps of the method in the first aspect.
In a fourth aspect, the embodiments of the present invention further provide a computer-readable storage medium, on which a computer program is stored, where the computer program is executed by a processor to perform the steps of the method in the first aspect.
The embodiment of the invention has the following beneficial effects:
the embodiment of the invention provides an oil return control method, an oil return control device and a multi-split system, wherein whether a refrigerant exists in an oil return capillary tube or not is intelligently judged according to outlet temperature, when the refrigerant exists, namely the internal oil quantity of a compressor is insufficient, current oil return control is carried out, and in the oil return control, the oil return frequency corresponding to the compressor is calculated according to calculation parameters and a preset Flooding formula, so that the oil return reliability is ensured, and the energy loss and the use comfort caused by overlarge output of the oil return frequency are avoided; meanwhile, oil return is carried out when the oil quantity in the compressor is insufficient, oil return according to needs is achieved, and therefore oil return frequency is reduced.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.
In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic structural diagram of a multi-split system according to an embodiment of the present invention;
fig. 2 is a flowchart of an oil return control method according to an embodiment of the present invention;
fig. 3 is a schematic diagram of an oil return control device according to an embodiment of the present invention.
Detailed Description
To make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
To facilitate understanding of the present embodiment, first, a detailed description is given below of an oil return control method provided in the embodiment of the present invention; the execution main body is a controller of the multi-split system. Specifically, the multi-split system includes an outdoor unit and a plurality of indoor units, as shown in fig. 1, two indoor units are taken as an example.
The outdoor unit comprises a gas-liquid separator 11, a compressor 12, an oil separator 13, an outdoor heat exchanger 14 and a four-way valve 15, wherein an exhaust temperature sensing bulb 121 is arranged in an exhaust pipe of the compressor 12, a high-pressure sensor 161 is arranged on a connecting pipeline between the oil separator 13 and the four-way valve 15, a low-pressure sensor 162 is arranged on a connecting pipeline between the gas-liquid separator 11 and the four-way valve 15, an oil return capillary tube 17 is connected to the bottom of the oil separator 13, and an oil temperature sensing bulb 171 is arranged at an outlet of the oil return capillary tube 17 and used for detecting the outlet temperature of the oil return capillary tube 17; an outdoor electronic expansion valve 18 is also connected to the outlet of the outdoor heat exchanger 14.
The outdoor unit is connected to the plurality of indoor units through an air-conditioning air pipe and an air-conditioning liquid pipe, and as shown in fig. 1, an air pipe shutoff valve 21 is provided in the air-conditioning air pipe, a liquid pipe shutoff valve 22 is provided in the air-conditioning liquid pipe, and a filter 23 is provided in each of the air-conditioning air pipe and the air-conditioning liquid pipe. Each indoor unit also comprises an indoor heat exchanger 31 and an indoor unit electronic expansion valve 32, and the indoor heat exchanger 31 is provided with an annular temperature sensing bulb 33, an indoor air pipe temperature sensing bulb 34 and an indoor liquid pipe temperature sensing bulb 35; it should be noted that, for parts not mentioned in the multi-split system, reference may be specifically made to the existing multi-split system, and details of the embodiment of the present invention are not described herein again.
Based on the multi-split air conditioning system, an embodiment of the present invention provides an oil return control method, as shown in fig. 2, the method includes the following steps:
step S202, acquiring the outlet temperature of the oil return capillary in real time;
specifically, for the multi-split system, when oil exists in the oil separator 13, the refrigeration oil flows in the oil return capillary 17; when there is no oil in the oil separator 13, the high-pressure gas refrigerant, i.e., the refrigerant, flows through the oil return capillary tube 17; because there is a great difference between the specific heat capacity and the density of the refrigerant oil and the gaseous refrigerant, it can be known from the heat transfer formula that when the refrigerant oil or the gaseous refrigerant flows through the oil return capillary 17, the outlet temperature of the oil return capillary 17 has a great difference due to different heat dissipation amounts.
In practical application, the following characteristics can be obtained from the physical properties of the medium: specific heat capacity c of oil v oil = 1870J/(kg, DEG C) and density rho Oil ＝852kg/m 3 (ii) a Specific heat capacity c of refrigerant v refrigerant = 1131J/(kg, DEG C.) and density ρ Refrigerant ＝40.45kg/m 3 (ii) a The heat transfer formula is shown below:
Q＝(t 0 -t)hA＝(t 1 -t 2 )c v ρV (1)
wherein Q represents heat, h represents total heat transfer coefficient, and t 0 -t and t 1 -t 2 Representing the amount of change in temperature, A representing the heat exchange area, c v Represents specific heat capacity, ρ represents density, and V represents fluid volume in the oil return capillary.
Based on the above formula (1), when the refrigerant oil and the refrigerant respectively pass through the oil return capillary 17, the difference of the heat transfer amounts is
The difference of the heat transfer quantity results in the difference of the outlet temperature of the oil return capillary 17.
Therefore, the oil temperature bulb 171 is arranged at the outlet of the oil return capillary tube 17 and used for detecting the outlet temperature of the oil return capillary tube, so that the controller can accurately judge whether the oil separator 13 is oil-storing according to the change difference of the outlet temperature of the oil return capillary tube, and when the oil separator 13 is oil-free, the compressor 12 can be inferred to be oil-free, and the outlet temperature of the oil return capillary tube can be used as the judgment basis of the oil quantity of the compressor.
It should be noted that the outlet temperature of the oil return capillary tube may be obtained according to a preset period, or may be obtained in real time, and in order to facilitate performing oil return control in time, in the embodiment of the present invention, the controller obtains the outlet temperature of the oil return capillary tube, which is collected by the oil temperature bulb 171, in real time.
Step S204, judging whether a refrigerant exists in the oil return capillary tube or not according to the outlet temperature and a preset temperature threshold value;
in particular, the outlet temperature T of the oil return capillary tube detected in real time oil Calculating a predetermined temperature threshold T out And outlet temperature T oil The difference therebetween; judging whether the difference value is greater than a preset difference value threshold value a or not; if yes, judging that a refrigerant exists in the oil return capillary tube; when T is out -T oil When the pressure in the compressor is higher than a, the oil return capillary is not full of oil, the refrigerant exists, namely the compressor has the risk of oil shortage, and the multi-split air conditioning system enters oil return control at the moment. The value range of the preset difference threshold value a is 5-10, and is preferably 8.
For the above-mentioned preset temperature threshold T out The temperature T in the oil separator can be determined according to the outlet temperature of the oil return capillary tube when the oil quantity of the compressor is sufficient, and the temperature T in the oil separator is determined due to the fact that oil is discharged along with the compressor in = compression exhaust temperature-oil heat dissipation k, so the outlet temperature of the return oil capillary at this time is the preset temperature threshold T out ＝T in -oil return capillary heat loss h; wherein the value range of k is 3-7, preferably 5; the value range of h is 5-10, preferably 8. It should be noted that k and h can be set according to actual conditions due to differences in the option size of the oil separator and the length of the oil return capillary tube.
Step S206, if yes, current oil return control is carried out on the multi-split system;
specifically, the refrigerant oil inside the compressor 12 enters the oil separator 13 with the exhaust gas, and most of the oil returns to the compressor 12 through the oil return capillary tube 17; however, the oil separation efficiency of the oil separator 13 is different, and a small amount of oil circulates to the whole refrigeration system along with the refrigerant, adheres to the inner wall of the copper pipe, and is not returned for a long time, so that more and more oil is discharged, and the compressor 12 is lack of oil.
Therefore, when it is determined that the refrigerant exists in the oil return capillary tube according to the outlet temperature and the preset temperature threshold, the oil amount of the compressor is insufficient at this time, and an oil return action needs to be performed, that is, the controller performs oil return control on the multi-split air-conditioning system.
Step S208, in the current oil return control, calculating to obtain the flow rate of the refrigerant according to the calculation parameters and a preset Flooding formula;
specifically, calculating the parameters includes: refrigerant density, oil density, gravity acceleration, correction coefficient and the inner diameter of a piping of a compressor air suction pipe; the calculation parameters can be stored in the controller in advance to improve the efficiency of calculating the flow velocity of the refrigerant. Wherein, the conventional Flooding formula is as follows:
F＝ρ gas 1/2 ×V gas /((ρ oil -ρ gas )×g×d) 1/2 (2)
wherein ρ gas Indicating the density of the refrigerant, V gas Representing the flow velocity, p, of the refrigerant oil The oil density is shown, g is the gravitational acceleration, and d is the inner diameter of the pipe.
According to the above-mentioned Flooding formula, in order to overcome the gravity of the refrigeration oil, flooding is required to be equal to or greater than 1.2, and the flow rate of the refrigerant can be calculated according to the following formula, where Flooding =1.2, i.e. F = 1.2:
V gas ＝F×((ρ oil -ρ gas )×g×d) 1/2 /ρ gas 1/2 ×S (3)
where ρ is gas Denotes the density, V, of the refrigerant gas Representing the flow velocity, p, of the refrigerant oil The oil density is shown, g is the gravitational acceleration, d is the pipe inner diameter, and S is the correction coefficient. In the oil return control, the correction coefficient S is preferably 2.
Step S210, calculating according to the displacement and the volume coefficient of the compressor, the flow rate and the inner diameter of the piping to obtain the corresponding oil return frequency of the compressor in the current oil return control;
in practical application, the general oil return mode is to increase the frequency of the compressor and increase the flow rate of the refrigerant to take away the refrigerant oil attached to the copper pipe; however, under the same frequency, the refrigerant parameters (such as high pressure, low pressure and superheat degree) are different, the refrigerant flow rates are also different, if the set frequency is too high, the comfort is influenced more greatly, and if the frequency is too low, the oil return effect is influenced. Therefore, the method has important significance in accurately calculating the oil return frequency of the compressor.
Specifically, the oil return frequency is calculated according to the following formula:
wherein f is oil Indicates the oil return frequency, V gas Denotes the flow velocity of the refrigerant, d denotes the inner diameter of the piping, V cc The displacement of the compressor is shown, eta represents the volume coefficient of the compressor, and the value range is 0.92-0.98, and preferably 0.95.
Therefore, after the flow rate of the refrigerant is calculated in real time by the calculation parameters and the preset Flooding formula, the oil return frequency required by the compressor is calculated according to the formula (4), the reliability of oil return is ensured, and the energy loss and the use comfort caused by overlarge output of the oil return frequency are avoided.
And step S212, controlling the compressor to operate according to the oil return frequency.
Specifically, in the current oil return control, the controller controls the compressor to follow the oil return frequency f oil Operation, i.e. control of the compressor from the current operating frequency to the oil return frequency f oil And (5) operating. In addition, in the current oil return control, the controller also acquires the oil return frequency f of the compressor oil And controlling the multi-split air conditioner system to exit the current oil return control when the running time reaches a preset time N. The value range of N is 3 min-5 min, preferably 3min.
Preferably, the method further comprises: and in the current oil return control, adjusting the opening degree of the outdoor electronic expansion valve to a first oil return opening degree, and adjusting the opening degrees of the plurality of indoor electronic expansion valves to a second oil return opening degree. Specifically, the controller controls the compressor according to the oil return frequency f oil During operation, the opening degree of the electronic expansion valve of the outdoor unit is also adjusted from the current opening degree to a first oil return opening degree, wherein the first oil return opening degree is subjected to conventional oil return control, namely the electronic expansion valve is kept fully opened during cooling, and is adjusted to the first oil return opening degree during heating, and the value range of the first oil return opening degree is 160 pls-300 pls, preferably 200pls. Simultaneously, adjust a plurality of indoor set electronicsThe opening degree of the expansion valve is from the current opening degree to a second oil return opening degree, wherein the second oil return opening degree is a fixed value and ranges from 200pls to 300pls, and the value is preferably 250pls; therefore, the oil return frequency of the compressor and the opening degrees of the outdoor unit electronic expansion valve and the indoor unit electronic expansion valve are adjusted, so that the oil return effect and the oil return reliability of the multi-split system are further ensured.
According to the oil return control method provided by the embodiment of the invention, whether a refrigerant exists in an oil return capillary tube or not is intelligently judged according to the outlet temperature, when the refrigerant exists, namely the internal oil quantity of a compressor is insufficient, the current oil return control is carried out, and in the oil return control, the flow rate of the refrigerant is calculated in real time according to the calculation parameters and a preset Flooding formula due to different calculation parameters, so that the oil return frequency corresponding to the compressor is obtained through calculation, the oil return reliability is ensured, and the energy loss and the use comfort caused by the overlarge output of the oil return frequency are avoided; meanwhile, oil return is carried out when the oil quantity in the compressor is insufficient, oil return according to requirements is achieved, and therefore oil return frequency is reduced.
Further, the method further comprises: acquiring the last interval duration ta (n-1) of the multi-split system; the last interval time ta (n-1) is used for representing the interval time between the multi-split system exiting from the last oil return control and entering the current oil return control; judging whether the last interval time ta (n-1) is larger than a preset interval threshold t or not; if so, reducing and correcting the oil return frequency according to preset correction parameters, and controlling the compressor to operate according to the oil return frequency after the reducing and correcting. Specifically, when ta (n-1) > t, the oil return frequency is subjected to reduction correction according to a preset correction parameter (preferably 5%), namely, in the current oil return control, the oil return frequency f is calculated oil Then, on the basis of the frequency change, the oil return frequency f is reduced by 5 percent oil And correcting the frequency, and taking the oil return frequency after the correction is reduced as the final oil return frequency of the compressor.
And if the last interval time ta (n-1) is less than the preset interval threshold t, increasing and correcting the oil return frequency according to the preset correction parameters, and controlling the compressor to operate according to the oil return frequency after increasing and correcting. I.e. when ta (n-1) < t,increasing and correcting the oil return frequency according to preset correction parameters, namely calculating the oil return frequency f in the current oil return control oil Then, on the basis of the frequency change amount, the oil return frequency f is increased by 5 percent oil And correcting the frequency, and taking the oil return frequency after the frequency is increased and corrected as the final oil return frequency of the compressor. The value range of the preset interval threshold t is 3 h-5 h, and preferably 4h.
Therefore, when the oil return amount is insufficient, the compressor enters oil return again after running for a short time, namely when the time interval between two times of oil return control is too short, the existing calculated oil return frequency is low, the oil return effect is poor, and when the next time of oil return control is started, the controller automatically corrects the calculated oil return frequency so as to improve the oil return amount.
To sum up, the oil return control method provided by the embodiment of the invention intelligently judges the internal oil quantity of the compressor based on the outlet temperature in the oil return capillary, so that oil return is carried out as required, the oil return frequency is reduced, and the energy loss and the use comfort caused by frequent oil return are avoided; in addition, in the oil return process, the flow rate of the refrigerant is calculated in real time according to the calculation parameters and a preset Flooding formula so as to calculate and obtain the oil return frequency corresponding to the compressor, and the oil return effect is accurately controlled, so that the oil return reliability is ensured, and the energy loss and the use comfort caused by overlarge output of the oil return frequency are avoided; and the oil return frequency of the compressor in the next oil return control is automatically corrected by combining the oil return interval, namely the preset interval threshold value t, so that the oil return effect of the multi-split air-conditioning system is further ensured.
Corresponding to the method embodiment, the embodiment of the invention also provides an oil return control device which is applied to a controller of a multi-split system, and the multi-split system further comprises a compressor and an oil return capillary tube. As shown in fig. 3, the apparatus includes: the system comprises a temperature acquisition module 31, a refrigerant judgment module 32, an oil return control module 33, a flow rate calculation module 34, a frequency calculation module 35 and an operation control module 36; the functions of each module are as follows:
the temperature acquisition module 31 is used for acquiring the outlet temperature of the oil return capillary in real time;
the refrigerant judgment module 32 is configured to judge whether a refrigerant exists in the oil return capillary tube according to the outlet temperature and a preset temperature threshold;
the oil return control module 33 is used for performing current oil return control on the multi-split system if the current oil return control is positive;
the flow rate calculation module 34 is configured to calculate a flow rate of the refrigerant according to the calculation parameter and a preset Flooding formula in the current oil return control; wherein, calculating the parameters comprises: refrigerant density, oil density, gravity acceleration, correction coefficient and the inner diameter of a piping of a compressor suction pipe;
the frequency calculation module 35 is configured to calculate an oil return frequency corresponding to the compressor in the current oil return control according to the displacement and the volume coefficient of the compressor, the flow rate, and the inner diameter of the piping;
and an operation control module 36 for controlling the compressor to operate at the oil return frequency.
According to the oil return control device provided by the embodiment of the invention, whether a refrigerant exists in the oil return capillary tube or not is intelligently judged according to the outlet temperature, when the refrigerant exists, namely the internal oil quantity of the compressor is insufficient, the current oil return control is carried out, and in the oil return control, the oil return frequency corresponding to the compressor is calculated according to the calculation parameters and the preset Flooding formula, so that the oil return reliability is ensured, and the energy loss and the use comfort caused by the overlarge output of the oil return frequency are avoided; meanwhile, oil return is carried out when the oil quantity in the compressor is insufficient, oil return according to requirements is achieved, and therefore oil return frequency is reduced.
Preferably, the above apparatus further comprises: acquiring the last interval duration of the multi-split system; the last interval duration is used for representing the interval duration from the time when the multi-split air conditioning system exits the last oil return control to the time when the multi-split air conditioning system enters the current oil return control; judging whether the previous interval duration is greater than a preset interval threshold or not; if so, reducing and correcting the oil return frequency according to preset correction parameters, and controlling the compressor to operate according to the oil return frequency after the oil return frequency is reduced and corrected.
Preferably, the above apparatus further comprises: and if the last interval duration is less than the preset interval threshold, increasing and correcting the oil return frequency according to preset correction parameters, and controlling the compressor to operate according to the increased and corrected oil return frequency.
Preferably, the above apparatus further comprises: and in the current oil return control, the running time of the compressor running according to the oil return frequency is obtained, and when the running time reaches the preset time, the multi-split air conditioning system is controlled to exit the current oil return control.
Preferably, the refrigerant determination module 32 is further configured to: calculating a difference between a preset temperature threshold and an outlet temperature; judging whether the difference value is larger than a preset difference value threshold value or not; if yes, the refrigerant is judged to exist in the oil return capillary tube.
Preferably, the multi-split air conditioner system further includes an outdoor electronic expansion valve and a plurality of indoor electronic expansion valves, and the apparatus further includes: and in the current oil return control, adjusting the opening degree of the outdoor electronic expansion valve to a first oil return opening degree, and adjusting the opening degrees of the plurality of indoor electronic expansion valves to a second oil return opening degree.
Preferably, the first oil return opening degree is 200pls, and the second oil return opening degree is 250pls.
The oil return control device provided by the embodiment of the invention has the same technical characteristics as the oil return control method provided by the embodiment, so that the same technical problems can be solved, and the same technical effects can be achieved.
The embodiment of the present invention further provides a multi-split system, which includes a processor and a memory, where the memory stores machine executable instructions that can be executed by the processor, and the processor executes the machine executable instructions to implement the oil return control method.
The present embodiments also provide a machine-readable storage medium storing machine-executable instructions that, when invoked and executed by a processor, cause the processor to implement the oil return control method described above.
The oil return control method and apparatus provided in the embodiments of the present invention, and the computer program product of the multi-split system include a computer-readable storage medium storing a program code, where instructions included in the program code may be used to execute the method described in the foregoing method embodiments, and specific implementation may refer to the method embodiments, and will not be described herein again.
It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the system and the apparatus described above may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In addition, in the description of the embodiments of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a non-volatile computer-readable storage medium executable by a processor. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
Finally, it should be noted that: the above-mentioned embodiments are only specific embodiments of the present invention, which are used for illustrating the technical solutions of the present invention and not for limiting the same, and the protection scope of the present invention is not limited thereto, although the present invention is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: those skilled in the art can still make modifications or changes to the embodiments described in the foregoing embodiments, or make equivalent substitutions for some features, within the scope of the disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the embodiments of the present invention, and they should be construed as being included therein. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. The oil return control method is characterized by being applied to a controller of a multi-split air conditioning system, wherein the multi-split air conditioning system further comprises a compressor and an oil return capillary tube; the method comprises the following steps:
acquiring the outlet temperature of the oil return capillary in real time;
judging whether a refrigerant exists in the oil return capillary tube or not according to the outlet temperature and a preset temperature threshold;
if so, performing current oil return control on the multi-split system;
in the current oil return control, calculating to obtain the flow rate of the refrigerant according to a calculation parameter and a preset Flooding formula; wherein the calculating parameters include: refrigerant density, oil density, gravitational acceleration, correction coefficient and the inner diameter of the piping of the compressor suction pipe;
calculating to obtain the corresponding oil return frequency of the compressor in the current oil return control according to the displacement and volume coefficient of the compressor, the flow rate and the inner diameter of the piping;
and controlling the compressor to operate according to the oil return frequency.
2. The method of claim 1, further comprising:
acquiring the last interval duration of the multi-split system; the last interval duration is used for representing the interval duration between the time when the multi-split air conditioning system exits from the last oil return control and the time when the multi-split air conditioning system enters the current oil return control;
judging whether the last interval duration is greater than a preset interval threshold or not;
if so, carrying out reduction correction on the oil return frequency according to preset correction parameters, and controlling the compressor to operate according to the oil return frequency after the reduction correction.
3. The method of claim 2, further comprising:
and if the last interval duration is smaller than the preset interval threshold, increasing and correcting the oil return frequency according to the preset correction parameter, and controlling the compressor to operate according to the oil return frequency after increasing and correcting.
4. The method according to any one of claims 1-3, further comprising:
and in the current oil return control, acquiring the operation time length of the compressor operating according to the oil return frequency, and controlling the multi-split air conditioner system to quit the current oil return control when the operation time length reaches a preset time length.
5. The method of claim 1, wherein the step of determining whether a refrigerant is present in the oil return capillary tube according to the outlet temperature and a preset temperature threshold comprises:
calculating a difference between the preset temperature threshold and the outlet temperature;
judging whether the difference value is larger than a preset difference value threshold value or not;
if yes, the refrigerant is judged to exist in the oil return capillary tube.
6. The method of claim 1, wherein the multiple split air line system further comprises an outdoor electronic expansion valve and a plurality of indoor electronic expansion valves, the method further comprising:
and in the current oil return control, adjusting the opening degree of the outdoor electronic expansion valve to a first oil return opening degree, and adjusting the opening degrees of the plurality of indoor electronic expansion valves to a second oil return opening degree.
7. The method of claim 6, wherein the first oil return opening is 200pls and the second oil return opening is 250pls.
8. The oil return control device is characterized by being applied to a controller of a multi-split air conditioner system, wherein the multi-split air conditioner system further comprises a compressor and an oil return capillary tube; the device comprises:
the temperature acquisition module is used for acquiring the outlet temperature of the oil return capillary in real time;
the refrigerant judgment module is used for judging whether a refrigerant exists in the oil return capillary tube or not according to the outlet temperature and a preset temperature threshold;
the oil return control module is used for performing current oil return control on the multi-split air conditioning system if the current oil return control is positive;
the flow rate calculation module is used for calculating the flow rate of the refrigerant according to calculation parameters and a preset Flooding formula in the current oil return control; wherein the calculating parameters include: refrigerant density, oil density, gravitational acceleration, correction coefficient and the inner diameter of the piping of the compressor suction pipe;
the frequency calculation module is used for calculating and obtaining the oil return frequency corresponding to the compressor in the current oil return control according to the displacement and the volume coefficient of the compressor, the flow rate and the inner diameter of the piping;
and the operation control module is used for controlling the compressor to operate according to the oil return frequency.
9. A multi-split system comprising a memory, a processor and a computer program stored on said memory and executable on said processor, characterized in that said processor implements the steps of the method as claimed in any one of the preceding claims 1 to 7 when executing said computer program.
10. A computer-readable storage medium, characterized in that a computer program is stored on the computer-readable storage medium, which computer program, when being executed by a processor, performs the steps of the method of any of the preceding claims 1-7.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211183317.4A CN115654796A (en) | 2022-09-27 | 2022-09-27 | Oil return control method and device and multi-split system |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211183317.4A CN115654796A (en) | 2022-09-27 | 2022-09-27 | Oil return control method and device and multi-split system |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117387253A (en) * | 2023-12-08 | 2024-01-12 | 珠海格力电器股份有限公司 | Unit oil return control method and device and water chilling unit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117387253A (en) * | 2023-12-08 | 2024-01-12 | 珠海格力电器股份有限公司 | Unit oil return control method and device and water chilling unit |
| CN117387253B (en) * | 2023-12-08 | 2024-03-08 | 珠海格力电器股份有限公司 | Unit oil return control method and device and water chilling unit |
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