CN117490184B - Air conditioning unit oil return control method and air conditioning unit - Google Patents

Air conditioning unit oil return control method and air conditioning unit Download PDF

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Publication number
CN117490184B
CN117490184B CN202311850089.6A CN202311850089A CN117490184B CN 117490184 B CN117490184 B CN 117490184B CN 202311850089 A CN202311850089 A CN 202311850089A CN 117490184 B CN117490184 B CN 117490184B
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China
Prior art keywords
oil
compressor
weight ratio
separator
air conditioning
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CN202311850089.6A
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CN117490184A (en
Inventor
吴晨祎
李冠铖
刘家豪
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Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
    • F24F11/32—Responding to malfunctions or emergencies
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B31/00—Compressor arrangements
    • F25B31/002—Lubrication
    • F25B31/004—Lubrication oil recirculating arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat
    • F25B43/02—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat for separating lubricants from the refrigerant
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2500/00—Problems to be solved
    • F25B2500/16—Lubrication
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Analytical Chemistry (AREA)
  • Power Engineering (AREA)
  • Control Of Positive-Displacement Pumps (AREA)

Abstract

The invention discloses an air conditioning unit oil return control method and an air conditioning unit, wherein the method comprises the following steps: acquiring the current oil-to-weight ratio of an air conditioning unit; wherein the oil-to-weight ratio is the specific gravity between the refrigerant of the air conditioning unit and the refrigerant of the compressor; judging whether the compressor lacks oil according to the current oil weight ratio; judging the position of lubricating oil when the compressor lacks oil; and controlling the air conditioning unit to return oil according to the position of the lubricating oil. The invention solves the problem that the operation of the compressor is affected by insufficient oil return quantity of the compressor in the prior art, effectively judges whether the compressor has the risk of oil-deficient operation, and timely recovers lubricating oil in a system to ensure the oil quantity in the compressor and ensure the reliable operation of a unit.

Description

Air conditioning unit oil return control method and air conditioning unit
Technical Field
The invention relates to the technical field of air conditioners, in particular to an oil return control method of an air conditioner unit and the air conditioner unit.
Background
In the refrigeration and chiller industry, the specific gravity of the refrigerant to the refrigerant is not met because refrigerant starvation and additional charge often occurs in the refrigeration system, which may exceed the maximum charge of the compressor. The oil quantity is relatively insufficient, so that poor lubrication of the compressor is caused, abrasion is increased, the service life of the compressor is influenced, and the reliability of the unit is reduced.
Aiming at the problem that the operation of the compressor is affected by insufficient oil return quantity of the compressor in the related technology, no effective solution is proposed at present.
Disclosure of Invention
The invention provides an oil return control method of an air conditioning unit and the air conditioning unit, which at least solve the problem that the operation of a compressor is affected by insufficient oil return quantity of the compressor in the prior art.
In order to solve the above technical problems, according to an aspect of the embodiments of the present invention, there is provided an oil return control method for an air conditioning unit, including: acquiring the current oil-to-weight ratio of an air conditioning unit; wherein the oil-to-weight ratio is the specific gravity between the refrigerant of the air conditioning unit and the refrigerant of the compressor; judging whether the compressor lacks oil according to the current oil weight ratio; judging the position of lubricating oil when the compressor lacks oil; and controlling the air conditioning unit to return oil according to the position of the lubricating oil.
Further, obtaining the oil-to-weight ratio of the air conditioning unit includes: acquiring the current oil level of a compressor and the current refrigerant quantity of an air conditioning unit; and calculating the specific gravity between the current oil level of the compressor and the current refrigerant quantity of the air conditioning unit, and determining the current oil-to-weight ratio.
Further, judging whether the compressor is starved according to the oil-to-weight ratio, comprising: acquiring an initial oil-to-weight ratio; judging whether the current oil-to-weight ratio is smaller than the initial oil-to-weight ratio or not; and when the current oil weight ratio is smaller than the initial oil weight ratio, determining that the compressor is oil-deficient, otherwise, determining that the compressor is not oil-deficient.
Further, the positions of the lubricating oil at least comprise: the oil separator and other parts except the oil separator; judging the position of the lubricating oil comprises the following steps: acquiring the oil level of the compressor and the oil level of the oil separator; judging whether the lubricating oil is only positioned in the oil separator according to the oil level of the compressor and the oil level of the oil separator; when the lubricating oil is not only in the oil separator, it is determined that the lubricating oil is also located in other portions than the oil separator.
Further, judging whether the lubricating oil is located only in the oil separator based on the oil level of the compressor and the oil level of the oil separator, comprising: calculating an oil level variation value of the compressor; wherein the oil level variation value is a difference between the oil level of the compressor and the initial oil level; judging that the oil level change value is equal to the oil level of the oil separator; if so, determining that the lubricating oil is located in the oil separator, otherwise, determining that the lubricating oil is not located in the oil separator.
Further, the positions of the lubricating oil at least comprise: the oil separator and other parts except the oil separator; the air conditioning unit is controlled to return oil according to the position of lubricating oil, and the method comprises the following steps: when the lubricating oil is positioned in the oil separator, controlling the oil separator to return oil to the compressor; when the lubricating oil is positioned in other parts of the oil separator, controlling the refrigerant in other parts of the oil separator to enter the oil separator and controlling the oil separator to return to the compressor.
Further, the air conditioning unit is provided with an oil return pump which is positioned at a liquid outlet of the oil separator and an oil return port of the compressor; oil return to the compressor by the control oil separator comprises: determining the interval where the current oil-to-weight ratio is located; and determining the operating frequency of the oil return pump according to the interval where the current oil weight ratio is located, and controlling the oil return pump to return oil according to the operating frequency.
Further, determining the operating frequency of the oil return pump according to the interval where the current oil-to-weight ratio is located, including: determining an operating frequency p=po of the oil return pump when the current oil-to-weight ratio is smaller than a first preset oil-to-weight ratioPo is the rated power of the scavenge pump, L1 is the current oil level of the compressor, and L0 is the initial oil level of the compressor; determining an operating frequency p=po of the oil return pump when the current oil weight ratio is greater than or equal to a first preset oil weight ratio and less than or equal to a second preset oil weight ratio*L2 is the current oil level of the oil separator, N1 is the current oil weight ratio, N0 is the initial oil weight ratio, and the second preset oil weight ratio is larger than the first preset oil weight ratio.
Further, the other parts than the oil separator at least comprise: a condenser, a gas-liquid separator, and an evaporator; the air conditioning unit is provided with a liquid return pump which is positioned between other parts except the oil separator and an inlet of the oil separator; controlling refrigerant at other parts of the oil separator to enter the oil separator, comprising: when the current oil weight ratio is smaller than the first preset oil weight ratio, determining the running frequency P1=Pe of the liquid return pumpPe is the rated power of the liquid return pump, L2 is the current oil level of the oil separator, L1 is the current oil level of the compressor, and L0 is the initial oil level of the compressor; when the current oil weight ratio is greater than or equal to the first preset oil weight ratio and less than or equal to the second preset oil weight ratio, determining the operation frequency of the liquid return pumpRate p1=pe*N1 is the current oil weight ratio, N0 is the initial oil weight ratio, and the second preset oil weight ratio is larger than the first preset oil weight ratio.
Further, the method further comprises the following steps: acquiring the suction superheat degree Ts of the compressor; judging whether the compressor has suction liquid according to the suction superheat degree Ts; if yes, controlling the opening of the liquid return pump, wherein the running frequency P1=Pe of the liquid return pump is equal to or less than the preset value。
According to another aspect of the embodiment of the present invention, there is provided an air conditioning unit including a compressor, an oil separator, a condenser, an evaporator, and a gas-liquid separator connected in this order, the air conditioning unit further including: the oil return pump is positioned at the liquid outlet of the oil separator and the oil return port of the compressor and is used for controlling the oil separator to return oil to the compressor; one end of the liquid return pump is connected with the condenser, the evaporator and the gas-liquid separator, the other end of the liquid return pump is connected with the inlet of the oil separator, and the refrigerant of the condenser, the evaporator and the gas-liquid separator is controlled to enter the oil separator so as to return oil to the compressor through the oil separator; the air conditioning unit adopts the oil return control method of the air conditioning unit to return oil.
According to yet another aspect of embodiments of the present invention, there is provided a storage medium containing computer executable instructions for performing an air conditioning unit oil return control method as described above when executed by a computer processor.
In the invention, an oil return control scheme of a compressor is provided, whether the compressor is starved or not is judged through the oil weight ratio of an air conditioning unit, and when the compressor is starved, the position of lubricating oil is judged and oil return is carried out. Through the scheme, whether the compressor has the risk of oil shortage operation or not can be effectively judged, the lubricating oil in the system is timely recovered, the oil quantity in the compressor is ensured, and the reliable operation of the unit is ensured.
Drawings
FIG. 1 is a schematic view of an alternative configuration of an air conditioning unit according to an embodiment of the present invention;
fig. 2 is an alternative flow chart of an air conditioning unit oil return control method according to an embodiment of the present invention.
Reference numerals illustrate:
1. a compressor; 2. an oil separator; 3. a four-way reversing valve; 4. a condenser; 5. a reservoir; 6. drying the filter; 7. a throttle valve; 8. a liquid supply stop valve; 9. an evaporator; 10. an air suction shutoff valve; 11. a gas-liquid separator; 12. an air suction temperature sensing bulb; 13. a low pressure sensor; 14. an exhaust temperature sensing bag; 15. a high-pressure sensor; 16. a liquid return pump; 17. a first stop valve; 18. a second shut-off valve; 19. a third stop valve; 20. a fourth shut-off valve; 21. an oil return pump; 22. an oil return electromagnetic valve; 23. a capillary tube; 24. and (3) a filter.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, the "plurality" generally includes at least two.
It should be understood that the term "and/or" as used herein is merely one relationship describing the association of the associated objects, meaning that there may be three relationships, e.g., a and/or B, may represent: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.
It should be understood that although the terms first, second, third, etc. may be used to describe the controllers in the embodiments of the present invention, these controllers should not be limited to these terms. These terms are only used to distinguish between controllers connected to different devices. For example, a first controller may also be referred to as a second controller, and similarly, a second controller may also be referred to as a first controller, without departing from the scope of embodiments of the invention.
The words "if", as used herein, may be interpreted as "at … …" or "at … …" or "in response to a determination" or "in response to a detection", depending on the context. Similarly, the phrase "if determined" or "if detected (stated condition or event)" may be interpreted as "when determined" or "in response to determination" or "when detected (stated condition or event)" or "in response to detection (stated condition or event), depending on the context.
It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a product 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 product or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a commodity or device comprising such element.
Alternative embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
Example 1
In a preferred embodiment 1 of the present invention, there is provided an oil return control method of an air conditioning unit, where the control method may be directly applied to the air conditioning unit, and fig. 1 shows an alternative structural schematic diagram of the air conditioning unit, and as shown in fig. 1, the air conditioning unit includes:
the compressor, the oil separator, the condenser, the evaporator and the gas-liquid separator are connected in sequence;
the air conditioning unit further includes: the oil return pump is positioned at the liquid outlet of the oil separator and the oil return port of the compressor and is used for controlling the oil separator to return oil to the compressor;
and one end of the liquid return pump is connected with the condenser, the evaporator and the gas-liquid separator, and the other end of the liquid return pump is connected with the inlet of the oil separator, so that the refrigerant of the condenser, the evaporator and the gas-liquid separator is controlled to enter the oil separator to return oil to the compressor through the oil separator.
In the refrigerating system, refrigerant flows out from the exhaust port of the compressor, reaches the oil separator, and then reaches the condenser through the four-way reversing valve to be condensed. After the refrigerant is liquefied, the refrigerant flows to the liquid storage device, a part of refrigerant is stored, after the refrigerant is absorbed and filtered by the drying filter, the refrigerant flows to the electronic expansion valve to be throttled, the refrigerant enters the evaporator through the liquid supply stop valve, the refrigerant coming out of the evaporator returns to the gas-liquid separator through the air suction stop valve to be separated, the liquid refrigerant is accumulated at the bottom of the gas-liquid separator, and then enters the air suction end of the compressor to start the next refrigeration cycle. The oil separator conveys the separated oil to the bottom of the compressor through an oil return pipeline, and a branch is used for pumping refrigerant from the condenser, the gas-liquid separator and the evaporator through the oil return pump and conveying the refrigerant to the oil separator.
According to buoy scales in the compressor and buoy scales in the oil separator, the oil level is determined, the air suction temperature and the air suction pressure of the compressor are detected through the pressure sensor and the temperature sensing bag, the air suction superheat degree is determined, further whether the compressor is in risk of oil shortage operation is judged, the refrigerating oil in the system is timely recovered, the oil quantity in the compressor is ensured, and reliable operation of the unit is ensured.
Based on the above air conditioning unit, in a preferred embodiment 1 of the present invention, an oil return control method of an air conditioning unit is provided, so as to effectively satisfy the oil return amount of a compressor, and ensure the service life of the compressor and the operational reliability of the unit. Specifically, fig. 2 shows an alternative flow chart of the method, as shown in fig. 2, comprising the following steps S202-S208:
s202: acquiring the current oil-to-weight ratio of an air conditioning unit; wherein the oil-to-weight ratio is the specific gravity between the refrigerant of the air conditioning unit and the refrigerant of the compressor;
s204: judging whether the compressor is short of oil or not according to the current oil-to-weight ratio;
s206: judging the position of lubricating oil when the compressor lacks oil;
s208: and controlling the air conditioning unit to return oil according to the position of the lubricating oil.
In the above embodiment, a compressor oil return control scheme is provided, which determines whether the compressor is starved according to the oil weight ratio of the air conditioning unit, and determines the position of the lubricating oil and returns oil when the compressor is starved. Through the scheme, whether the compressor has the risk of oil shortage operation or not can be effectively judged, the lubricating oil in the system is timely recovered, the oil quantity in the compressor is ensured, and the reliable operation of the unit is ensured.
The method for obtaining the oil-to-weight ratio of the air conditioning unit comprises the following steps: acquiring the current oil level of a compressor and the current refrigerant quantity of an air conditioning unit; and calculating the specific gravity between the current oil level of the compressor and the current refrigerant quantity of the air conditioning unit, and determining the current oil-to-weight ratio. The oil-to-weight ratio is the weight ratio of the lubricating oil to the refrigerant, and the lubricating oil and the refrigerant are poured according to the preset oil-to-weight ratio before the air conditioning unit leaves the factory, so that the oil-to-weight ratio can be maintained at the preset oil-to-weight ratio when the air conditioning unit works well, the oil-to-weight ratio can be reduced when the air conditioning unit lacks oil, and whether the air conditioning unit lacks oil can be judged by adopting the oil-to-weight ratio.
Specifically, judging whether the compressor is starved according to the oil-to-weight ratio includes: acquiring an initial oil-to-weight ratio; judging whether the current oil-to-weight ratio is smaller than the initial oil-to-weight ratio or not; and when the current oil weight ratio is smaller than the initial oil weight ratio, determining that the compressor is oil-deficient, otherwise, determining that the compressor is not oil-deficient.
When the compressor lacks oil, the possible condition is that lubricating oil enters an oil separator, and the possible condition is that lubricating oil enters all parts of the system, and the position of the lubricating oil at least comprises: the oil separator and other parts except the oil separator; other parts of the oil separator may be a condenser, an evaporator and a gas-liquid separator.
Judging the position of the lubricating oil comprises the following steps: acquiring the oil level of the compressor and the oil level of the oil separator; judging whether the lubricating oil is only positioned in the oil separator according to the oil level of the compressor and the oil level of the oil separator; when the lubricating oil is not only in the oil separator, it is determined that the lubricating oil is also located in other portions than the oil separator.
Further, judging whether the lubricating oil is located only in the oil separator based on the oil level of the compressor and the oil level of the oil separator, comprising: calculating an oil level variation value of the compressor; wherein the oil level variation value is a difference between the oil level of the compressor and the initial oil level; judging that the oil level change value is equal to the oil level of the oil separator; if so, determining that the lubricating oil is located in the oil separator, otherwise, determining that the lubricating oil is not located in the oil separator. If the lubricant oil of the compressor enters the oil separator, the compressor oil level change value is equal to the oil level of the oil separator (the initial oil level of the oil separator defaults to 0), and if the compressor oil level change value is smaller than the oil level of the oil separator, the lubricant oil also enters the system everywhere except the oil separator.
The air conditioning unit is controlled to return oil according to the position of lubricating oil, and the method comprises the following steps: when the lubricating oil is positioned in the oil separator, controlling the oil separator to return oil to the compressor; when the lubricating oil is still located in other parts of the oil separator, controlling the refrigerant in other parts of the oil separator to enter the oil separator, and controlling the oil separator to return to the compressor.
As shown in fig. 1, the air conditioning unit is provided with an oil return pump which is positioned at a liquid outlet of the oil separator and an oil return port of the compressor; oil return to the compressor by the control oil separator comprises: determining the interval where the current oil-to-weight ratio is located; and determining the operating frequency of the oil return pump according to the interval where the current oil weight ratio is located, and controlling the oil return pump to return oil according to the operating frequency.
Specifically, determining the operating frequency of the oil return pump according to the interval where the current oil-to-weight ratio is located includes: determining an operating frequency p=po of the oil return pump when the current oil-to-weight ratio is smaller than a first preset oil-to-weight ratioPo is the rated power of the scavenge pump, L1 is the current oil level of the compressor, and L0 is the initial oil level of the compressor; determining an operating frequency p=po of the oil return pump when the current oil weight ratio is greater than or equal to a first preset oil weight ratio and less than or equal to a second preset oil weight ratio*L2 is the current oil level of the oil separator, N1 is the current oil weight ratio, N0 is the initial oil weight ratio, and the second preset oil weight ratio is larger than the first preset oil weight ratio.
As shown in fig. 1, the other parts than the oil separator include at least: a condenser, a gas-liquid separator, and an evaporator; the air conditioning unit is provided with a liquid return pump which is positioned between other parts except the oil separator and an inlet of the oil separator; controlling refrigerant at other parts of the oil separator to enter the oil separator, comprising: when the current oil weight ratio is smaller than the first preset oil weight ratio, determining the running frequency P1=Pe of the liquid return pumpPe is the rated power of the liquid return pump, L2 is the current oil level of the oil separator, L1 is the current oil level of the compressor, and L0 is the initial oil level of the compressor; when the current oil weight ratio is greater than or equal to the first preset oil weight ratio and less than or equal to the second preset oil weight ratio, determining the operation frequency P1=Pe of the liquid return pump*N1 is the current oil weight ratio, N0 is the initial oil weight ratio, and the second preset oil weight ratio is larger than the first preset oil weight ratio.
For example, the oil level L0 and the refrigerant amount M0 at the initial time of the compressor, the oil weight ratio n0=l0/M0, the oil level L1 in the compressor, the oil level L2 in the oil separator, and the oil weight ratio n1=l1/M0 are detected at a certain time of the cooling operation.
(1) When N1 is less than 0.3, L0-L1=L2, gas-liquid separator,The first stop valve, the second stop valve and the third stop valve from the evaporator and the condenser to the liquid return pump are all closed, and the fourth stop valve from the liquid return pump to the compressor is opened, so that the input power P=Po of the liquid return pump is calculatedPo is the rated power of the oil return pump, the frozen oil at the bottom of the oil separator is conveyed into the compressor, and if L1 is detected to be more than or equal to L0 in 60 seconds continuously, the oil return pump is closed;
(2) When N1 is detected to be less than 0.3 at a certain moment, and (L0-L1) is more than L2, the first stop valve, the second stop valve and the third stop valve from the gas-liquid separator, the evaporator and the condenser to the liquid return pump are opened, the input power P=Po of the liquid return pump is calculatedConveying the oil separator and the refrigerating oil remained in the refrigerating system into a compressor, and closing a liquid return pump if L1 is detected to be more than or equal to L0 in 60 seconds continuously;
(3) When detecting that N1 is more than or equal to 0.3 and less than or equal to 0.4 at a certain moment, L0-L1=L2, the first stop valve, the second stop valve and the third stop valve from the gas-liquid separator, the evaporator and the condenser to the liquid return pump are all closed, and the fourth stop valve from the liquid return pump to the compressor is opened, the input power P=Po of the liquid return pump is calculated*If L1 is more than or equal to L0 in 60 seconds continuously, the oil return pump is closed;
(4) When detecting that N1 is more than or equal to 0.3 and less than or equal to 0.4 at a certain moment, and (L0-L1) is more than L2, opening a first stop valve, a second stop valve and a third stop valve from the gas-liquid separator, the evaporator and the condenser to the liquid return pump, then inputting power P=Po of the liquid return pump*If L1 is more than or equal to L0 in 60 seconds continuously, the liquid return pump is turned off;
(5) When N1 is detected to be more than 0.4 at a certain moment, the first stop valve, the second stop valve and the third stop valve from the gas-liquid separator, the evaporator and the condenser to the liquid return pump are closed, the fourth stop valve from the liquid return pump to the compressor is opened, and the input power P=Po of the liquid return pump is calculated*If L1 is less than or equal to L0 in 60 seconds continuously, the oil return pump is closed. At this time, according to the judgment condition N1 > 0.4, the oil weight in the compressor is relatively large, the amount of the frozen oil in the compressor is relatively large, the oil level does not need to be repeatedly detected, the frozen oil in the compressor is directly transferred into the oil separator, and when the oil level in the compressor is detected to be reduced to the original oil level L0, the control is ended.
In another preferred embodiment of the present invention, further comprising: acquiring the suction superheat degree Ts of the compressor; judging whether the compressor has suction liquid according to the suction superheat degree Ts; if yes, controlling the opening of the liquid return pump, wherein the running frequency P1=Pe of the liquid return pump is equal to or less than the preset value。
The intake superheat degree is an individual determination condition, and as long as the condition is satisfied, the corresponding oil return control is executed. The risk that the compressor is in liquid-carrying operation exists when the suction superheat degree is too small, meanwhile, the liquid-state refrigerant in the compressor can dilute lubricating oil, and the operation reliability of the compressor cannot be guaranteed. Therefore, when the suction superheat is small, the oil return control is performed.
For example, when the suction superheat Ts is detected to be less than 5 ℃ at a certain moment, the first stop valve, the second stop valve and the third stop valve from the gas-liquid separator, the evaporator and the condenser to the liquid return pump are opened, and the input power p=po of the liquid return pumpWhen the suction superheat degree Ts is detected to be more than or equal to 5 ℃ for 10 minutes continuously, the liquid return pump is turned off.
Example 2
In a preferred embodiment 2 of the present invention, there is also provided an air conditioning unit for executing the oil return control method of the air conditioning unit provided in the above embodiment 1, as shown in fig. 1, the air conditioning unit includes:
the compressor, the oil separator, the condenser, the evaporator and the gas-liquid separator are connected in sequence;
the air conditioning unit further includes: the oil return pump is positioned at a liquid outlet of the oil separator and an oil return port of the compressor and is used for controlling the oil separator to return to the compressor;
and one end of the liquid return pump is connected with the condenser, the evaporator and the gas-liquid separator, the other end of the liquid return pump is connected with an inlet of the oil separator, and the refrigerant of the condenser, the evaporator and the gas-liquid separator is controlled to enter the oil separator so as to return oil to the compressor through the oil separator.
In the refrigerating system, refrigerant flows out from the exhaust port of the compressor, reaches the oil separator, and then reaches the condenser through the four-way reversing valve to be condensed. After the refrigerant is liquefied, the refrigerant flows to the liquid storage device, a part of refrigerant is stored, after the refrigerant is absorbed and filtered by the drying filter, the refrigerant flows to the electronic expansion valve to be throttled, the refrigerant enters the evaporator through the liquid supply stop valve, the refrigerant coming out of the evaporator returns to the gas-liquid separator through the air suction stop valve to be separated, the liquid refrigerant is accumulated at the bottom of the gas-liquid separator, and then enters the air suction end of the compressor to start the next refrigeration cycle. The oil separator conveys the separated oil to the bottom of the compressor through an oil return pipeline, and a branch is used for pumping refrigerant from the condenser, the gas-liquid separator and the evaporator through the oil return pump and conveying the refrigerant to the oil separator.
According to buoy scales in the compressor and buoy scales in the oil separator, the oil level is determined, the air suction temperature and the air suction pressure of the compressor are detected through the pressure sensor and the temperature sensing bag, the air suction superheat degree is determined, further whether the compressor is in risk of oil shortage operation is judged, the refrigerating oil in the system is timely recovered, the oil quantity in the compressor is ensured, and reliable operation of the unit is ensured.
In the above embodiment, a compressor oil return control scheme is provided, which determines whether the compressor is starved according to the oil weight ratio of the air conditioning unit, and determines the position of the lubricating oil and returns oil when the compressor is starved. Through the scheme, whether the compressor has the risk of oil shortage operation or not can be effectively judged, the lubricating oil in the system is timely recovered, the oil quantity in the compressor is ensured, and the reliable operation of the unit is ensured.
Example 3
Based on the air conditioning unit oil return control method provided in the above embodiment 1, there is also provided in a preferred embodiment 3 of the present invention a storage medium containing computer-executable instructions for performing the air conditioning unit oil return control method as described above when executed by a computer processor.
In the above embodiment, a compressor oil return control scheme is provided, which determines whether the compressor is starved according to the oil weight ratio of the air conditioning unit, and determines the position of the lubricating oil and returns oil when the compressor is starved. Through the scheme, whether the compressor has the risk of oil shortage operation or not can be effectively judged, the lubricating oil in the system is timely recovered, the oil quantity in the compressor is ensured, and the reliable operation of the unit is ensured.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
It is to be understood that the invention is not limited to the precise arrangements and instrumentalities shown in the drawings, which have been described above, and that various modifications and changes may be effected without departing from the scope thereof. The scope of the invention is limited only by the appended claims.

Claims (11)

1. An oil return control method of an air conditioning unit is characterized by comprising the following steps:
acquiring the current oil-to-weight ratio of an air conditioning unit; wherein the oil-to-weight ratio is the specific gravity between the refrigerant of the air conditioning unit and the refrigerant of the compressor;
judging whether the compressor is short of oil or not according to the current oil-to-weight ratio;
when the compressor lacks oil, judging the position of the lubricating oil, wherein the position of the lubricating oil at least comprises: the oil separator and other parts except the oil separator;
the air conditioning unit is controlled to return oil according to the position of the lubricating oil, wherein when the lubricating oil is positioned in the oil separator, the oil separator is controlled to return oil to the compressor; and when the lubricating oil is positioned in other parts of the oil separator, controlling the refrigerant in other parts of the oil separator to enter the oil separator, and controlling the oil separator to return to the compressor.
2. The method of claim 1, wherein the obtaining the current oil-to-weight ratio of the air conditioning unit comprises:
acquiring the current oil level of the compressor and the current refrigerant quantity of the air conditioning unit;
and calculating the specific gravity between the current oil level of the compressor and the current refrigerant quantity of the air conditioning unit, and determining the current oil-to-weight ratio.
3. The method of claim 2, wherein determining whether the compressor is starved based on the oil-to-weight ratio comprises:
acquiring an initial oil-to-weight ratio;
judging whether the current oil-to-weight ratio is smaller than the initial oil-to-weight ratio;
and when the current oil weight ratio is smaller than the initial oil weight ratio, determining that the compressor is starved, otherwise, determining that the compressor is not starved.
4. The method of claim 1, wherein the location of the lubricant comprises at least: the oil separator and other parts except the oil separator; judging the position of the lubricating oil comprises the following steps:
acquiring an oil level of the compressor and an oil level of the oil separator;
judging whether the lubricating oil is positioned in the oil separator or not according to the oil level of the compressor and the oil level of the oil separator;
and determining that the lubricating oil is positioned in other parts of the oil separator when the lubricating oil is not positioned in the oil separator.
5. The method of claim 4, wherein determining whether the lubricating oil is located within the oil separator based on an oil level of the compressor and an oil level of the oil separator comprises:
calculating an oil level variation value of the compressor; wherein the oil level variation value is a difference between an oil level of the compressor and an initial oil level;
judging that the oil level change value is equal to the oil level of the oil separator;
if so, determining that the lubricating oil is located in the oil separator, otherwise, determining that the lubricating oil is not located in the oil separator.
6. The method according to claim 1, wherein the air conditioning unit is provided with a scavenging pump located at a liquid outlet of the oil separator and at a scavenging port of the compressor; controlling oil return of the oil separator to the compressor, comprising:
determining the interval where the current oil-to-weight ratio is located;
and determining the operation frequency of the oil return pump according to the interval where the current oil weight ratio is located, and controlling the oil return pump to return oil according to the operation frequency.
7. The method of claim 6, wherein determining the operating frequency of the scavenge pump in accordance with the interval in which the current oil-to-weight ratio is located comprises:
when the current oil weight ratio is smaller than a first preset oil weight ratio, determining the operating frequency P=Po of the oil return pumpPo is the rated power of the oil return pump, L1 is the current oil level of the compressor, and L0 is the initial oil level of the compressor;
when the current oil weight ratio is greater than or equal to the first preset oil weight ratio and less than or equal to the second preset oil weight ratio, determining the operating frequency p=po of the oil return pump*/>L2 is the current oil level of the oil separator, N1 is the current oil weight ratio, N0 is the initial oil weight ratio, and the second preset oil weight ratio is larger than the first preset oil weight ratio.
8. The method of claim 1, wherein the other portions of the oil separator include at least: a condenser, a gas-liquid separator, and an evaporator; the air conditioning unit is provided with a liquid return pump which is positioned between other parts of the oil separator and an inlet of the oil separator; controlling the refrigerant at other parts of the oil separator to enter the oil separator, comprising:
when the current oil weight ratio is smaller than a first preset oil weight ratio, determining the running frequency P1=Pe of the liquid return pumpPe is the rated power of the liquid return pump, L2 is the current oil level of the oil separator, L1 is the current oil level of the compressor, and L0 is the initial oil level of the compressor;
when the current oil weight ratio is greater than or equal to the first preset oil weight ratio and less than or equal to the second preset oil weight ratio, determining the operation frequency p1=pe of the liquid return pump*/>N1 is the current oil weight ratio, N0 is the initial oil weight ratio, and the second preset oil weight ratio is larger than the first preset oil weight ratio.
9. The method as recited in claim 8, further comprising:
acquiring the suction superheat degree Ts of the compressor;
judging whether the compressor has suction liquid according to the suction superheat degree Ts;
if yes, controlling the liquid return pump to be started, wherein the running frequency P1=Pe of the liquid return pump。
10. The utility model provides an air conditioning unit, includes compressor, oil separator, condenser, evaporimeter, gas-liquid separator that connects gradually, its characterized in that, air conditioning unit still includes:
the oil return pump is positioned at a liquid outlet of the oil separator and an oil return port of the compressor and is used for controlling the oil separator to return to the compressor;
one end of the liquid return pump is connected with the condenser, the evaporator and the gas-liquid separator, the other end of the liquid return pump is connected with an inlet of the oil separator, and refrigerant of the condenser, the evaporator and the gas-liquid separator is controlled to enter the oil separator so as to return oil to the compressor through the oil separator;
wherein the air conditioning unit returns oil by adopting the air conditioning unit return oil control method as claimed in any one of claims 1 to 9.
11. A storage medium containing computer executable instructions, which when executed by a computer processor are for performing the air conditioning unit oil return control method according to any one of claims 1 to 9.
CN202311850089.6A 2023-12-29 2023-12-29 Air conditioning unit oil return control method and air conditioning unit Active CN117490184B (en)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114151992A (en) * 2021-12-22 2022-03-08 珠海格力电器股份有限公司 Compressor oil return control method and device and air conditioner
CN117053437A (en) * 2023-09-25 2023-11-14 深圳市英维克科技股份有限公司 Compressor oil return control method, electronic device and computer readable medium

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114151992A (en) * 2021-12-22 2022-03-08 珠海格力电器股份有限公司 Compressor oil return control method and device and air conditioner
CN117053437A (en) * 2023-09-25 2023-11-14 深圳市英维克科技股份有限公司 Compressor oil return control method, electronic device and computer readable medium

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