CN115993016A - Air conditioning system, air conditioning unit and control method - Google Patents

Air conditioning system, air conditioning unit and control method Download PDF

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Publication number
CN115993016A
CN115993016A CN202211542791.1A CN202211542791A CN115993016A CN 115993016 A CN115993016 A CN 115993016A CN 202211542791 A CN202211542791 A CN 202211542791A CN 115993016 A CN115993016 A CN 115993016A
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CN
China
Prior art keywords
refrigerant
gas
liquid separator
defrosting
air conditioning
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202211542791.1A
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Chinese (zh)
Inventor
张仕强
吴晓曼
陈敏
袁帆
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Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
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Application filed by Gree Electric Appliances Inc of Zhuhai filed Critical Gree Electric Appliances Inc of Zhuhai
Priority to CN202211542791.1A priority Critical patent/CN115993016A/en
Publication of CN115993016A publication Critical patent/CN115993016A/en
Priority to PCT/CN2023/109324 priority patent/WO2024113911A1/en
Pending legal-status Critical Current

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    • 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
    • F24F11/41—Defrosting; Preventing freezing
    • 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
    • F24F11/50—Control or safety arrangements characterised by user interfaces or communication
    • F24F11/54—Control or safety arrangements characterised by user interfaces or communication using one central controller connected to several sub-controllers
    • 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
    • F24F11/50—Control or safety arrangements characterised by user interfaces or communication
    • F24F11/61—Control or safety arrangements characterised by user interfaces or communication using timers
    • 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
    • F24F11/70—Control systems characterised by their outputs; Constructional details thereof
    • F24F11/80—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air
    • F24F11/83—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers
    • F24F11/84—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers using valves
    • 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
    • F24F11/70—Control systems characterised by their outputs; Constructional details thereof
    • F24F11/80—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air
    • F24F11/86—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling compressors within refrigeration or heat pump circuits
    • 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
    • F25B13/00—Compression machines, plants or systems, with reversible cycle
    • 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
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
    • F25B41/26—Disposition of valves, e.g. of on-off valves or flow control valves of fluid flow reversing valves
    • 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
    • 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
    • F25B45/00—Arrangements for charging or discharging 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
    • F25B47/00—Arrangements for preventing or removing deposits or corrosion, not provided for in another subclass
    • F25B47/02—Defrosting cycles
    • 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
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F2110/00—Control inputs relating to air properties
    • F24F2110/50—Air quality properties
    • F24F2110/64—Airborne particle content
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F2110/00—Control inputs relating to air properties
    • F24F2110/50—Air quality properties
    • F24F2110/65—Concentration of specific substances or contaminants
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F2140/00—Control inputs relating to system states
    • F24F2140/20—Heat-exchange fluid temperature
    • 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)
  • Human Computer Interaction (AREA)
  • Fluid Mechanics (AREA)
  • Analytical Chemistry (AREA)
  • Power Engineering (AREA)
  • Air Conditioning Control Device (AREA)
  • Compression-Type Refrigeration Machines With Reversible Cycles (AREA)

Abstract

The invention discloses an air conditioning system, an air conditioning unit and a control method, wherein the air conditioning system comprises: the compressor, the four-way valve, the outdoor heat exchanger, the throttling component and the indoor heat exchange module are sequentially connected to form a refrigerant circulation loop, and the refrigerant circulation loop is provided with a storage area for temporarily storing liquid refrigerant; the storage area is connected between the indoor heat exchange module and the four-way valve and is switched and connected on the suction side or the exhaust side of the compressor through the four-way valve. When the refrigerant circulation loop runs in the refrigeration cycle or the defrosting cycle, the storage area is connected to the suction side of the compressor; when the refrigerant circulation loop is switched to the heating circulation, the storage area is connected to the exhaust side of the compressor. According to the invention, the liquid refrigerant generated in the defrosting process can be transferred to the storage area, and when defrosting is switched to heating circulation, the stored liquid refrigerant is gasified and brought into the heating circulation by means of the high-temperature and high-pressure refrigerant of the exhaust gas, so that the effect of rapid heating after defrosting is finally achieved.

Description

Air conditioning system, air conditioning unit and control method
Technical Field
The invention relates to the technical field of air conditioning systems, in particular to an air conditioning system for realizing liquid refrigerant transfer, an air conditioning unit and a control method.
Background
At present, when the air conditioning system is in heating operation, the outdoor side is an evaporation side, and as the refrigerant evaporates and absorbs heat, the temperature of an outdoor side pipeline is reduced, and the surface of the outdoor heat exchanger is gradually frosted. When the defrosting operation of the air conditioning system is performed, a four-way valve is generally adopted to switch the flow direction of the refrigerant into refrigeration circulation, and the high-temperature gaseous refrigerant is utilized to enter the outdoor heat exchanger, so that the frost layer on the surface of the outdoor heat exchanger absorbs heat to realize defrosting. After defrosting is finished, the four-way valve switches the refrigerant flow direction to be heating circulation, and the air conditioning system resumes the heating mode operation. At this time, the refrigerant in the outdoor heat exchanger at the low-pressure side after defrosting cannot be transferred in time, and a large amount of liquid refrigerant is accumulated at the outdoor low-pressure side, so that the heating effect after defrosting is slow and the heat exchange efficiency is poor.
Meanwhile, the air conditioning system has the problem that the refrigerant circulation volume difference between the refrigerating mode and the heating mode is large, and under the condition of the refrigerant circulation volume meeting the heating mode requirement, the refrigerant circulation volume is excessive in the refrigerating mode, so that the high-low pressure difference of the system is large, the load of the compressor is large, and the energy-saving effect is poor.
Disclosure of Invention
In order to solve the problem that the refrigerant in the defrosting process of the existing air conditioning system is accumulated in an outdoor side heat exchanger, so that the heating effect after defrosting is slow, the invention provides an air conditioning system, an air conditioning unit and a control method for realizing liquid refrigerant transfer.
The invention adopts the technical scheme that an air conditioning system is designed, comprising: the compressor, the four-way valve, the outdoor heat exchanger, the throttling component and the indoor heat exchange module are sequentially connected to form a refrigerant circulation loop, and the refrigerant circulation loop is provided with a storage area for temporarily storing liquid refrigerant; the storage area is connected between the indoor heat exchange module and the four-way valve and is switched and connected on the suction side or the exhaust side of the compressor through the four-way valve.
In some embodiments, the storage area is an inner cavity of a gas-liquid separator, a first end of the gas-liquid separator is connected to an outlet side of the indoor heat exchange module under refrigeration cycle, and a second end of the gas-liquid separator is connected to the four-way valve.
Further, the refrigerant circulation loop is also provided with a refrigerant transfer branch circuit with controllable on-off state, the inlet end of the refrigerant transfer pipeline is connected to the outlet side of the outdoor heat exchanger under refrigeration circulation, and the outlet end of the refrigerant transfer pipeline is communicated to the inner cavity of the gas-liquid separator.
In some embodiments, the storage area is a low pressure side piping in the refrigerant circulation circuit, the low pressure side piping comprising: and a connecting pipeline between the indoor heat exchange module and the four-way valve.
In some embodiments, a connecting pipeline between the four-way valve and the outdoor heat exchanger is provided with a switching section, the switching section is connected with a gas-liquid separator, a first end of the gas-liquid separator is connected to one end of the switching section, which is close to the four-way valve, and a second end of the gas-liquid separator is connected to the other end of the switching section, which is close to the outdoor heat exchanger; the gas-liquid separator has controllable first end, second end and switching section.
Further, one end of the first end and the second end of the gas-liquid separator, which is connected with the four-way valve, is provided with an oil return hole, or the first end and the second end are provided with oil return holes, and the oil return holes are close to the bottom of the inner cavity of the gas-liquid separator.
Further, an oil return branch connected to the air suction side of the compressor is arranged at the bottom of the inner cavity of the gas-liquid separator, and the oil return branch is provided with an oil return valve and an oil return throttling piece.
The invention also provides an air conditioning unit, and the air conditioning unit adopts the air conditioning system.
In some embodiments, the air conditioning unit is a multi-split air conditioning unit, and the indoor heat exchange module comprises more than two indoor heat exchangers.
The invention also provides a control method of the air conditioning system, which is suitable for the embodiment that the storage area is the inner cavity of the gas-liquid separator, and comprises the following steps:
after the refrigerant circulation loop is in defrosting circulation, the superheat degree of the refrigerant at the outlet end of the gas-liquid separator is obtained;
judging whether the superheat degree of the refrigerant exceeds a set value;
if yes, the throttle component maintains the opening degree;
if not, the throttle assembly reduces the opening.
Further, the control method further comprises: before acquiring the superheat degree of the refrigerant at the outlet end of the gas-liquid separator, timing the actual defrosting duration of the defrosting cycle of the refrigerant circulation loop, and if the actual defrosting duration reaches a set duration threshold t c Acquiring the superheat degree of the refrigerant at the outlet end of the gas-liquid separator; wherein, a time length threshold t is set c <Setting total defrosting duration.
In some embodiments, the throttle assembly includes an outdoor throttle valve and an indoor throttle valve;
when the throttle assembly is judged to maintain the opening degree, the opening degrees of the outdoor throttle valve and the indoor throttle valve are maintained unchanged;
when it is determined that the throttle assembly decreases the opening, the opening of the outdoor throttle valve is maintained unchanged, and the opening of the indoor throttle valve is decreased.
Further, the superheat degree of the refrigerant is T Temperature of outlet pipe -T Low pressure saturation temperature ，T Temperature of outlet pipe Is the actual temperature of the outlet end of the gas-liquid separator, T Low pressure saturation temperature Is the saturation temperature corresponding to the suction side pressure of the compressor.
Further, the control method further comprises:
judging whether the operation parameters of the refrigerant circulation loop reach the set defrosting exit conditions or not in the defrosting circulation process;
if yes, the defrosting cycle is exited, the compressor is stopped, the four-way valve keeps the on state of the defrosting cycle, the throttling component is closed, a refrigerant transfer branch between the outdoor heat exchanger and the gas-liquid separator is connected until the operation parameters of the refrigerant cycle loop reach the preset reversing condition of the four-way valve;
if not, maintaining the defrosting cycle.
The invention provides a control method of an air conditioning system, which is suitable for an embodiment that a storage area is a low-pressure side piping in a refrigerant circulation loop, and comprises the following steps:
after the refrigerant circulation loop is in defrosting circulation, the suction superheat degree of the compressor is obtained;
adjusting the opening of the throttling assembly according to the suction superheat degree of the compressor;
if the suction superheat degree is higher than the target interval, the throttle assembly increases the opening degree;
if the suction superheat degree is in the target interval, the throttle assembly maintains the opening degree;
if the suction superheat is lower than the target interval, the throttle assembly reduces the opening degree.
Further, the range higher than the target interval is divided into at least two upper limit intervals, each upper limit interval is provided with a corresponding opening adjustment amplitude, and the opening adjustment amplitude of the upper limit interval with higher numerical value is larger; and/or dividing the range lower than the target interval into at least two lower limit intervals, wherein each upper limit interval is provided with a corresponding opening adjustment amplitude, and the opening adjustment amplitude of the lower limit interval with a lower value is larger.
In some embodiments, the throttle assembly includes an outdoor throttle valve and an indoor throttle valve;
after the refrigerant circulation loop operates for defrosting circulation, the outdoor throttle valve is opened to a set maximum opening;
When the throttle assembly is judged to maintain the opening degree, the opening degrees of the outdoor throttle valve and the indoor throttle valve are maintained unchanged;
when the throttle assembly is judged to reduce the opening degree, the opening degree of the outdoor throttle valve is maintained unchanged, and the opening degree of the indoor throttle valve is reduced;
when the throttle assembly is judged to increase the opening degree, the opening degree of the outdoor throttle valve is kept unchanged, and the opening degree of the indoor throttle valve is increased.
Further, the control method further comprises:
judging whether the operation parameters of the refrigerant circulation loop reach the set defrosting exit conditions or not in the defrosting circulation process;
if yes, the defrosting cycle is exited, the compressor is stopped, the four-way valve keeps the on state of the defrosting cycle, the throttling component is opened to the set maximum opening degree until the operation parameters of the refrigerant circulation loop reach the set four-way valve reversing condition;
if not, maintaining the defrosting cycle.
The invention also provides a control method of the air conditioning system, which is suitable for the embodiment of the air-liquid separator connected between the four-way valve and the outdoor heat exchanger, and comprises the following steps:
after the refrigerant circulation loop runs the refrigeration cycle or the defrosting cycle, the first end of the switching section and the first end of the gas-liquid separator are connected, and the second end of the gas-liquid separator is closed;
Timing the actual liquid storage time of the refrigerant circulation loop operation refrigeration cycle;
if the actual liquid storage time is longer than the set liquid storage time, only the switching section is connected, and the first end and the second end of the gas-liquid separator are closed.
In some embodiments, the liquid storage duration is set to be a first liquid storage duration corresponding to an actual running frequency of the compressor and/or a first liquid storage duration calculated according to a performance parameter of the air conditioning systemTwo-liquid storage time period, and a second liquid storage time period t Storage time The calculation formula of (2) is as follows: t is t Storage time Storage capacity of gas-liquid separator =x (compressor displacement x operating frequency x inlet cross-sectional area of gas-liquid separator); the storage capacity of the gas-liquid separator is the maximum refrigerant quantity required by the heating cycle of the refrigerant circulation loop minus the maximum refrigerant quantity required by the refrigeration cycle of the refrigerant circulation loop, and the operating frequency is the target liquid storage frequency of the compressor in the initial stage of the operation refrigeration cycle or defrosting cycle of the refrigerant circulation loop.
Compared with the prior art, the invention has the following beneficial effects:
1. transferring the liquid refrigerant generated in the defrosting process to a storage area, and when the defrosting is switched to a heating cycle, gasifying the liquid refrigerant stored in the storage area into the heating cycle by means of the high-temperature and high-pressure refrigerant of exhaust gas, so that the effect of rapid heating after defrosting is finally achieved;
2. Transferring liquid refrigerant generated by refrigeration cycle to a storage area, reducing the refrigerant circulation volume of the refrigeration cycle, and solving the problem of the difference of refrigerant circulation volume required by a refrigeration mode and a heating mode;
3. the gas-liquid separator is provided with an oil return hole and/or an oil return branch, so that oil return is realized in the operation process of the air conditioning system, and the operation reliability of the compressor is improved.
Drawings
The invention is described in detail below with reference to examples and figures, wherein:
FIG. 1 is a schematic diagram of a connection of a first embodiment of the present invention;
FIG. 1a is a schematic flow diagram of a first embodiment of the present invention during a refrigeration cycle or defrost cycle;
FIG. 1b is a schematic flow diagram of a first embodiment of the present invention during a heating cycle;
FIG. 2 is a schematic diagram of a connection of a second embodiment of the present invention;
FIG. 2a is a schematic flow diagram of a second embodiment of the present invention during a refrigeration cycle or a defrost cycle;
FIG. 2b is a schematic flow diagram of a second embodiment of the present invention during a shutdown for refrigerant transfer;
FIG. 2c is a schematic flow diagram of a second embodiment of the present invention during a heating cycle;
FIG. 3 is a schematic diagram of a third embodiment of the connection of the present invention;
FIG. 3a is a schematic flow diagram of a third embodiment of the present invention during a refrigeration cycle or a defrost cycle;
FIG. 3b is a schematic flow chart illustrating a third embodiment of the present invention when the refrigerant is transferred during a shutdown;
FIG. 3c is a schematic flow diagram of a third embodiment of the present invention during a heating cycle;
FIG. 4 is a schematic diagram of a fourth embodiment of the connection of the present invention;
fig. 4a is a schematic flow diagram of a fourth embodiment of the present invention in a refrigeration cycle or a defrost cycle;
FIG. 4b is a schematic flow diagram of a fourth embodiment of the present invention during a heating cycle;
FIG. 5 is a schematic diagram of a fifth embodiment of the present invention;
fig. 5a is a schematic flow diagram of a fifth embodiment of the present invention in a refrigeration cycle or a defrost cycle;
FIG. 5b is a schematic flow diagram of a fifth embodiment of the present invention during a heating cycle;
FIG. 6 is a schematic diagram of a connection of a sixth embodiment of the present invention;
fig. 6a is a schematic flow diagram of a sixth embodiment of the present invention in a refrigeration cycle or a defrost cycle;
FIG. 6b is a schematic flow chart of a sixth embodiment of the present invention when the refrigerant is transferred during a shutdown;
fig. 6c is a schematic flow diagram of a sixth embodiment of the present invention during a heating cycle.
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
As shown in fig. 1, the air conditioning system provided by the invention can solve the problem that the liquid refrigerant is stored in the outdoor heat exchanger after defrosting, and when defrosting is switched to a heating mode, the stored liquid refrigerant is gasified and brought into a heating cycle by virtue of the high-temperature and high-pressure refrigerant discharged by the compressor, so that the effect of rapid heating after defrosting is finally achieved.
Specifically, the air conditioning system includes: the compressor 1, the four-way valve 4, the outdoor heat exchanger 5, the throttling component and the indoor heat exchange module which are sequentially connected to form a refrigerant circulation loop are provided with an outdoor fan 6, the indoor heat exchange module comprises at least one indoor heat exchanger, the refrigerant circulation loop is provided with a storage area for temporarily storing liquid refrigerant, the storage area is connected between the indoor heat exchange module and the four-way valve 4, and the storage area is connected to the air suction side or the air exhaust side of the compressor 1 through the four-way valve 4 in a switching mode.
When the refrigerant circulation loop runs in refrigeration cycle or defrosting cycle, the storage area is connected to the air suction side of the compressor 1, the refrigerant is sent back to the air suction side of the compressor 1 through the storage area, and the liquid refrigerant is stored through the storage area, so that the liquid refrigerant is prevented from accumulating in the outdoor heat exchanger; when the refrigerant circulation loop is switched to the heating circulation, the storage area is connected to the exhaust side of the compressor 1, the high-temperature refrigerant discharged by the compressor 1 passes through the storage area, and the liquid refrigerant in the storage area is heated and gasified by the high-temperature refrigerant and then is brought into the refrigeration circulation, so that the effect of rapid heating after defrosting is achieved.
It should be understood that the refrigerant flow directions of the defrosting cycle and the refrigerating cycle are the same, and the refrigerant flow direction in the refrigerant circulation loop is the exhaust port of the compressor 1, the four-way valve 4, the outdoor heat exchanger 5, the throttling component, the indoor heat exchange module and the air suction port of the compressor 1. The refrigerant flow direction in the refrigerant circulation loop of the heating cycle is the exhaust port of the compressor 1, the four-way valve 4, the indoor heat exchange module, the throttling component, the outdoor heat exchanger 5 and the air suction port of the compressor 1. Of course, other components may be designed in the refrigerant circulation circuit, but in different circulation states of the refrigerant circulation circuit, the order of the main components of the refrigerant flowing through the compressor 1, the four-way valve 4, the outdoor heat exchanger 5, the throttling assembly, the indoor heat exchange module and the like should follow the corresponding flow directions.
The storage area is illustrated in connection with various embodiments.
As shown in fig. 1, in the first embodiment of the present invention, the storage area is an inner cavity of the gas-liquid separator 10, the gas-liquid separator 10 has a first end 101 and a second end 102, one of the first end 101 and the second end 102 is used as an inlet, the other is used as an outlet, the C end of the four-way valve 4 is connected with the outdoor heat exchanger 5, the D end is connected with the exhaust side of the compressor 1 through the oil separator 3, the E end is connected with the second end of the gas-liquid separator 10, the S end is connected with the suction side of the compressor 1, the bottom of the oil separator 3 is connected with the suction side of the compressor 1 through the capillary tube 2, and the first end of the gas-liquid separator 10 is connected with the outlet side of the indoor heat exchange module under refrigeration cycle.
As shown in fig. 1a, when the refrigerant circulation circuit is in defrosting circulation or refrigerating circulation, the refrigerant is discharged from the compressor 1, enters the outdoor heat exchanger 5 through the oil separator 3 and the four-way valve 4 to be condensed and heat exchanged, enters the indoor heat exchange module through the throttling component to exchange heat, enters the inner cavity from the first end 101 of the gas-liquid separator 10, flows out from the second end 102 of the gas-liquid separator 10, returns to the air suction side of the compressor 1 through the four-way valve 4, and stores the liquid refrigerant flowing out from the indoor heat exchange module through the gas-liquid separator 10.
As shown in fig. 1b, when the refrigerant circulation circuit is in operation and heating cycle, the refrigerant is discharged from the compressor 1, enters the gas-liquid separator 10 through the oil separator 3 and the four-way valve 4, enters the gas-liquid separator 10 from the second end 102 of the gas-liquid separator 10, flows out from the first end 101 of the gas-liquid separator 10, enters the indoor heat exchange module, is sent to the outdoor heat exchanger 5 for evaporation and heat exchange, returns to the air suction side of the compressor 1 through the four-way valve 4, and gasifies the liquid refrigerant stored in the gas-liquid separator 10 through the high-temperature refrigerant discharged by the compressor 1, thereby improving the heating efficiency and simultaneously recovering the refrigerant circulation quantity required by the heating mode.
As shown in fig. 2, in the second embodiment of the present invention, the connection structure of the second embodiment is the same as that of the first embodiment, except that the refrigerant circulation circuit is further provided with a refrigerant transfer branch circuit with controllable on-off state, the inlet end of the refrigerant transfer pipeline is connected to the outlet side of the outdoor heat exchanger 5 under refrigeration cycle, and the outlet end of the refrigerant transfer pipeline is connected to the inner cavity of the gas-liquid separator 10. The refrigerant transfer branch is provided with a refrigerant transfer valve 13, and the on-off state of the refrigerant transfer branch is controlled through the refrigerant transfer valve 13.
As shown in fig. 2a to 2c, the refrigerant circulation circuit of the second embodiment has the same operation state as the first embodiment, except that in the shutdown state between the end of defrosting circulation of the refrigerant circulation circuit and the entering of heating cycle, the refrigerant transfer valve 13 is opened to connect the refrigerant transfer line, and the liquid refrigerant of the outdoor heat exchanger 5 is moved to the gas-liquid separator 10 through the refrigerant transfer line by utilizing the pressure difference between the high pressure side and the low pressure side of the refrigerant circulation circuit, so that the liquid refrigerant in the outdoor heat exchanger 5 is reduced, and the reliability of the four-way valve 4 during switching is ensured.
As shown in fig. 3, in a third embodiment of the present invention, the storage area is a low pressure side pipe in the refrigerant circulation circuit, the C end of the four-way valve 4 is connected to the outdoor heat exchanger 5, the D end is connected to the exhaust side of the compressor through the oil separator 3, the E end is connected to the indoor heat exchange module, the S end is connected to the suction side of the compressor 1, the bottom of the oil separator 3 is connected back to the suction side of the compressor 1 through the capillary tube 2, and the low pressure side pipe includes: and a connecting pipeline between the E end of the four-way valve 4 and the indoor heat exchange module.
As shown in fig. 3a, when the refrigerant circulation circuit is in defrosting circulation or refrigerating circulation, the refrigerant is discharged from the compressor, enters the outdoor heat exchanger 5 through the oil separator 3 and the four-way valve 4 to be condensed and heat exchanged, enters the indoor heat exchange module through the throttling assembly to exchange heat, flows into the low-pressure side piping, and returns to the suction side of the compressor 1 through the four-way valve 4.
As shown in fig. 3b, when the refrigerant circulation circuit exits the defrosting cycle or the refrigerating cycle, the compressor is stopped, the four-way valve is kept in the on state of the defrosting cycle or the refrigerating cycle, the opening degree of the throttle assembly is opened to a set maximum opening degree, and the refrigerant is transferred from the outdoor heat exchanger 5 to the low-pressure side piping under the pressure difference between the high-pressure side and the low-pressure side of the air conditioning system.
As shown in fig. 3c, when the refrigerant circulation circuit is operated to perform heating cycle, the refrigerant is discharged from the compressor 1, enters the low-pressure side piping through the oil separator 3 and the four-way valve 4, flows out of the low-pressure side piping, enters the indoor heat exchange module, and is sent to the outdoor heat exchanger 5 to perform evaporation heat exchange, returns to the suction side of the compressor 1 through the four-way valve 4, and the high-temperature refrigerant discharged from the compressor gasifies the liquid refrigerant stored in the low-pressure side piping, thereby improving the heating efficiency and recovering the refrigerant circulation amount required by the hot mode.
Because the refrigerating mode and the heating mode of the air conditioning system have larger difference in the refrigerant circulation quantity, the air conditioning system provided by the invention can also solve the problem of excessive refrigerant circulation quantity in the refrigerating cycle, and when in refrigerating cycle, part of refrigerant is sent into the gas-liquid separator so as to achieve the effect of reducing the refrigerant circulation quantity of the refrigerating cycle.
The following describes an example of a structure for adjusting the refrigerant circulation amount.
As shown in fig. 4, in the fourth embodiment of the present invention, the C-end of the four-way valve 4 is connected to the outdoor heat exchanger, the D-end is connected to the discharge side of the compressor 1 through the oil separator 3, the E-end is connected to the indoor heat exchange module, the S-end is connected to the suction side of the compressor 1, the connecting line between the C-end of the four-way valve 4 and the outdoor heat exchanger 5 is provided with a switching section, the bottom of the oil separator 3 is connected back to the suction side of the compressor 1 through the capillary tube 2, the switching section is connected with the gas-liquid separator 10, the gas-liquid separator 10 has a first end 101 and a second end 102, one of the first end 101 and the second end 102 serves as an inlet, the other serves as an outlet, the first end 101 of the gas-liquid separator 10 is connected to the end of the switching section close to the four-way valve 4, and the second end 102 of the gas-liquid separator 10 is connected to the other end of the switching section close to the outdoor heat exchanger 5, i.e. the second end 102 of the gas-liquid separator 10 is connected to the inlet side of the outdoor heat exchanger 5 under refrigeration cycle. The first end 101 of the gas-liquid separator 10 is provided with a first switch valve 14, the second end 102 is provided with a second switch valve 16, the switching section is provided with a third switch valve 15, and the on-off states of the first end 101, the second end 102 and the switching section of the gas-liquid separator 10 are controlled through the first to third switch valves.
As shown in fig. 4a, when the refrigerant circulation loop is in defrosting circulation or refrigerating circulation, the first switch valve 14 and the third switch valve 15 are opened, the second switch valve 16 is closed, the refrigerant is discharged from the compressor 1, after passing through the oil separator 3 and the four-way valve 4, a part of the refrigerant enters the gas-liquid separator 10 through the first end 101 of the gas-liquid separator 10 to naturally condense and store liquid, and the other part enters the outdoor heat exchanger 5 through the switching section to condense and exchange heat, enters the indoor heat exchange module through the throttling assembly to exchange heat, and then returns to the air suction side of the compressor 1 through the four-way valve 4, and a large amount of liquid refrigerant is stored in the compressor 1 through the gas-liquid separator 10 to avoid entering the compressor 1, so that the power consumption of the compressor 1 is reduced, and the reliability of the system is improved.
As shown in fig. 4b, when the refrigerant circulation circuit is in operation and heating cycle, the first switch valve 14 and the second switch valve 16 are opened, the third switch valve 15 is closed, the refrigerant is discharged from the compressor 1, enters the indoor heat exchange module through the oil separator 3 and the four-way valve 4, then is sent to the outdoor heat exchanger 5 for evaporation and heat exchange, enters the gas-liquid separator through the second end 102 of the gas-liquid separator 10, flows out from the first end 101 of the gas-liquid separator 10, and returns to the suction side of the compressor 1 through the four-way valve 4.
In the embodiment designed with the gas-liquid separator, for better oil return of the system, the gas-liquid separator 10 is provided with an oil return structure, and the oil return structure can be designed as an oil return hole and/or an oil return branch, and the lubricating oil in the gas-liquid separator 10 is sent back to the compressor through the oil return structure, so that the reliability of the compressor is ensured.
The oil return structure is illustrated below in connection with the examples.
As shown in fig. 1, in the first embodiment of the present invention, the first end 101 of the gas-liquid separator 10 extends upward from the bottom of the inner cavity, and the second end 102 of the gas-liquid separator 10 extends downward from the top of the inner cavity, and then extends upward after bending the bottom of the inner cavity. The first end 101 and the second end 102 of the gas-liquid separator 10 are provided with oil return holes 103, and the oil return holes 103 are close to the bottom of the inner cavity.
During the refrigeration cycle or the defrosting cycle, the refrigerant is sent to the gas-liquid separator 10 from the second end 102, and lubricating oil entering the pipeline from the oil return hole of the second end 102 is brought back to the compressor 1 in the process that the refrigerant flows through the second end 102. Under the heating cycle, the refrigerant is sent to the gas-liquid separator 10 from the first end 101, and in the process that the refrigerant flows through the first end 101, the lubricating oil entering the pipeline from the oil return hole of the first end 101 is brought to the indoor heat exchange module, and then returns to the compressor 1 through the outdoor heat exchanger 5. Because the oil return holes 103 are designed at the first end 101 and the second end 102 of the gas-liquid separator 10, the oil return of the gas-liquid separator 10 can be realized without changing the current operation mode, the oil return is quick and efficient, and the operation reliability and the user comfort level of the compressor 1 can be greatly improved.
In a second embodiment of the invention, as shown in fig. 2, the first end 101 of the gas-liquid separator 10 extends downwardly from the top of the chamber, and the second end 102 of the gas-liquid separator 10 extends downwardly from the top of the chamber, and then upwardly after bending at the bottom of the chamber. The second ends 102 of the gas-liquid separators 10 are provided with oil return holes 103, and the oil return holes 103 are close to the bottom of the inner cavity.
During the refrigeration cycle or the defrosting cycle, the refrigerant is sent to the gas-liquid separator 10 from the second end 102, and lubricating oil entering the pipeline from the oil return hole of the second end 102 is brought back to the compressor 1 in the process that the refrigerant flows through the second end 102. Because the oil return hole 103 is only designed at the second end of the gas-liquid separator 10, only the refrigerant flow direction of the refrigeration cycle or the defrosting cycle is supported to realize oil return, the heating cycle cannot realize oil return, the air conditioning system needs to be controlled to enter an oil return mode, and the refrigerant circulation loop is switched to the refrigeration cycle, so that the oil return of the gas-liquid separator 10 can be realized.
In a fourth embodiment of the invention, as shown in fig. 4, the second end 102 of the gas-liquid separator 10 extends downwardly from the top of the cavity, and the first end 101 of the gas-liquid separator 10 extends downwardly from the top of the cavity and upwardly after bending at the bottom of the cavity. The first end 101 of the gas-liquid separator 10 is provided with an oil return hole 103, and the oil return hole 103 is near the bottom of the inner cavity.
Under the heating cycle, the refrigerant is sent to the gas-liquid separator 10 from the first end 101, and in the process that the refrigerant flows through the first end 101, the lubricating oil entering the pipeline from the oil return hole 103 of the first end 101 is brought back to the compressor 1. Since the second end 102 of the gas-liquid separator 10 is closed during the refrigeration cycle or the defrosting cycle in the fourth embodiment, the oil return hole 103 is not designed for the second end 102 of the gas-liquid separator 10, and only the refrigerant flow direction of the heating cycle is supported to realize the oil return.
As shown in fig. 5 to 5b, in the fifth embodiment of the present invention, which is the same as the connection structure of the first embodiment, the refrigerant circulation circuit operation state of the fifth embodiment is the same as that of the first embodiment, except that the bottom of the inner chamber of the gas-liquid separator 10 is further provided with an oil return branch connected to the suction side of the compressor 1, the oil return branch is provided with an oil return valve 11 and an oil return throttling member 12, and the oil return throttling member 12 is generally referred to as a capillary tube. When the oil return valve 11 is opened, lubricating oil in the inner cavity of the gas-liquid separator 10 returns to the compressor 1 through the oil return throttling piece 12, so that the operation reliability of the compressor 1 is ensured.
As shown in fig. 6 to 6c, in a sixth embodiment of the present invention, which is the same as the second embodiment in connection structure, the refrigerant circulation circuit of the sixth embodiment is also the same in operation state as the second embodiment, except that an oil return branch is further provided at the bottom of the inner chamber of the gas-liquid separator, the oil return branch is connected to the suction side of the compressor, the oil return branch is provided with an oil return valve 11 and an oil return throttling member 12, and the oil return throttling member 12 is generally referred to as a capillary tube. When the oil return valve 11 is opened, lubricating oil in the inner cavity of the gas-liquid separator 10 returns to the compressor 1 through the oil return throttling piece 12, so that the operation reliability of the compressor 1 is ensured.
In order to realize accurate regulation and control of different embodiments, the invention also provides a control method of the air conditioning system, and the process of the control method is described in detail below in combination with each embodiment.
As shown in fig. 1 and 5, the control method according to the first and fifth embodiments is as follows.
After the refrigerant circulation loop is in defrosting circulation, the refrigerant superheat degree of the outlet end, namely the second end 102, of the gas-liquid separator 10 is obtained, whether the refrigerant superheat degree exceeds a set value is judged, if so, the temperature inside the gas-liquid separator 10 is higher, the refrigerant inside the gas-liquid separator 10 is in an evaporation state, the refrigerant storage height inside the gas-liquid separator can be ensured not to exceed the limit capacity of the gas-liquid separator during defrosting, the opening degree of the throttling component is maintained, if not, the temperature inside the gas-liquid separator 10 is lower, the possibility of condensing and liquefying the refrigerant of the gas-liquid separator 10 is higher, and the opening degree of the throttling component is reduced, so that the liquid storage amount of the gas-liquid separator 10 is reduced.
Wherein, the refrigerant superheat degree is preferably calculated by T Temperature of outlet pipe -T Low pressure saturation temperature ，T Temperature of outlet pipe Is the actual temperature of the outlet end of the gas-liquid separator, T Low pressure saturation temperature The actual temperature of the outlet end of the gas-liquid separator 10 is compared with the saturation temperature of the low pressure side of the system to accurately reflect the refrigerant state in the gas-liquid separator.
In order to improve the accuracy of the opening adjustment of the throttling assembly, the control method further comprises the following steps: after the refrigerant circulation loop operates the defrosting circulation, timing the actual defrosting duration of the refrigerant circulation loop operation defrosting circulation, and if the actual defrosting duration reaches a set duration threshold t c The refrigerant superheat at the outlet end, the second end 102, of the gas-liquid separator 10 is obtained. Wherein, a time length threshold t is set c <Setting total defrosting duration. That is, the control method is to run in the refrigerant circulation loop for a period of time-set time threshold t c And detecting the superheat degree of the refrigerant of the gas-liquid separator 10, predicting whether the liquid stored in the gas-liquid separator 10 exceeds the limit capacity according to the superheat degree of the refrigerant, and operating the throttling assembly according to the judgment result until defrosting is finished.
Specifically, the throttle assembly includes an outdoor throttle valve 7 and an indoor throttle valve, the outdoor throttle valve 7 is installed at an outlet side of the outdoor heat exchanger 5 under the refrigeration cycle, and the indoor throttle valve is installed at an inlet side of the indoor heat exchange module under the refrigeration cycle. When the opening degree of the throttling assembly is judged to be maintained, the opening degrees of the outdoor throttling valve 7 and the indoor throttling valve are maintained unchanged until defrosting is finished; when it is determined that the throttle assembly decreases the opening, the opening of the outdoor throttle valve 7 is maintained unchanged, and the opening of the indoor throttle valve decreases until defrosting is completed. Of course, in practical application, if only one throttle valve is provided between the outdoor heat exchanger and the indoor heat exchange module, the opening degree control is performed according to the above adjustment manner of the indoor throttle valve.
Judging whether the operation parameters of the refrigerant circulation loop reach the set defrosting exit conditions or not in the defrosting circulation process; if yes, the defrosting cycle is exited, the compressor 1 is stopped, the four-way valve 4 keeps the on state of the defrosting cycle until the operation parameters of the refrigerant circulation loop reach the preset four-way valve reversing condition, and the four-way valve 4 is switched to the on state of the heating cycle; if not, maintaining the defrosting cycle.
It should be noted that, in the above description, "set value", "set duration threshold t c "etc. can be obtained by experimental statistics, and the set value may be a constant of 0℃or higher, for example, 3 ℃. The set defrosting exit condition can be designed to be that the actual defrosting time reaches the set defrosting total time, namely, the refrigerant circulation loop exits the defrosting circulation when the actual defrosting time reaches the set defrosting total time. The reversing condition of the four-way valve can be designed to be that the difference between the discharge side pressure and the suction side pressure of the compressor is reduced to a set pressure difference, namely, when the difference between the discharge side pressure and the suction side pressure of the compressor is reduced to the set pressure difference, the four-way valve is electrified and is switched to the on state of the heating cycle, the compressor is started, and the refrigerant circulation loop operates the heating cycle.
As shown in fig. 2 and 6, the control method according to the second and sixth embodiments is as follows.
After the refrigerant circulation loop is in defrosting circulation, the refrigerant superheat degree of the outlet end-the second end 102 of the gas-liquid separator 10 is obtained, whether the refrigerant superheat degree exceeds a set value is judged, if so, the temperature inside the gas-liquid separator 10 is higher, the refrigerant inside the gas-liquid separator 10 is in an evaporation state, the refrigerant storage height inside the gas-liquid separator 10 can be ensured not to exceed the limit capacity of the gas-liquid separator 10 during defrosting, the opening degree of the throttling component is maintained, if not, the temperature inside the gas-liquid separator 10 is lower, the possibility of condensing and liquefying the refrigerant inside the gas-liquid separator 10 is higher, and the opening degree of the throttling component is reduced, so that the liquid storage amount of the gas-liquid separator 10 is reduced.
Wherein, the refrigerant superheat degree is preferably calculated by T Temperature of outlet pipe -T Low pressure saturation temperature ，T Temperature of outlet pipe Is the actual temperature of the outlet end of the gas-liquid separator, T Low pressure saturation temperature For the saturation temperature corresponding to the suction side pressure of the compressor, the actual temperature of the outlet end of the gas-liquid separator is compared with the saturation temperature of the low pressure side of the system, so that the gas-liquid can be accurately reflectedRefrigerant state in the separator.
In order to improve the accuracy of the opening adjustment of the throttling assembly, the control method further comprises the following steps: after the refrigerant circulation loop operates the defrosting circulation, timing the actual defrosting duration of the refrigerant circulation loop operation defrosting circulation, and if the actual defrosting duration reaches a set duration threshold t c The superheat degree of the refrigerant at the outlet end of the gas-liquid separator 10 is obtained. Wherein, a time length threshold t is set c <Setting total defrosting duration. That is, the control method is to run in the refrigerant circulation loop for a period of time-set time threshold t c And detecting the superheat degree of the refrigerant of the gas-liquid separator 10, predicting whether the liquid stored in the gas-liquid separator 10 exceeds the limit capacity according to the superheat degree of the refrigerant, and operating the throttling assembly according to the judgment result until defrosting is finished.
Specifically, the throttle assembly includes an outdoor throttle valve 7 and an indoor throttle valve, the outdoor throttle valve 7 is installed at an outlet side of the outdoor heat exchanger 5 under the refrigeration cycle, and the indoor throttle valve is installed at an inlet side of the indoor heat exchange module under the refrigeration cycle. When the opening degree of the throttling assembly is judged to be maintained, the opening degrees of the outdoor throttling valve 7 and the indoor throttling valve are maintained unchanged until defrosting is finished; when it is determined that the throttle assembly decreases the opening, the opening of the outdoor throttle valve 7 is maintained unchanged, and the opening of the indoor throttle valve decreases until defrosting is completed. Of course, in practical application, if only one throttle valve is provided between the outdoor heat exchanger and the indoor heat exchange module, the opening degree control is performed according to the above adjustment manner of the indoor throttle valve.
Judging whether the operation parameters of the refrigerant circulation loop reach the set defrosting exit conditions or not in the defrosting circulation process; if yes, the defrosting cycle is exited, the compressor 1 is stopped, the four-way valve 4 keeps the on state of the defrosting cycle, the throttling component is closed, a refrigerant transfer branch between the outdoor heat exchanger 5 and the gas-liquid separator 10 is connected, the liquid refrigerant of the outdoor heat exchanger 5 flows to the gas-liquid separator 10 through the refrigerant transfer branch until the operation parameters of the refrigerant circulation loop reach the preset four-way valve reversing condition, the four-way valve 4 is switched to the on state of the heating cycle, the throttling component is opened, and the refrigerant transfer branch is closed; if not, maintaining the defrosting cycle.
It should be noted that, in the above description, "set value", "set duration threshold t c "etc. can be obtained by experimental statistics, and the set value may be a constant of 0℃or higher, for example, 3 ℃. The set defrosting exit condition can be designed to be that the actual defrosting time reaches the set defrosting total time, namely, the refrigerant circulation loop exits the defrosting circulation when the actual defrosting time reaches the set defrosting total time. The reversing condition of the four-way valve can be designed to be that the difference between the discharge side pressure and the suction side pressure of the compressor is reduced to a set pressure difference, namely, when the difference between the discharge side pressure and the suction side pressure of the compressor is reduced to the set pressure difference, the four-way valve is electrified and is switched to the on state of the heating cycle, the compressor is started, and the refrigerant circulation loop operates the heating cycle.
As shown in fig. 3, for the third embodiment, the procedure of the control method is as follows.
After the refrigerant circulation loop is in defrosting circulation, the suction superheat degree of the compressor 1 is obtained, the opening degree of the throttling assembly is adjusted according to the suction superheat degree of the compressor 1, if the suction superheat degree is higher than a target interval, the temperature of the suction side of the compressor 1 is higher, the refrigerant flowing through the indoor heat exchange module is insufficient, the opening degree of the throttling assembly is increased, if the suction superheat degree is in the target interval, the operation state of the compressor 1 is moderate, the throttling assembly maintains the opening degree, if the suction superheat degree is lower than the target interval, the temperature of the suction side of the compressor 1 is lower, the refrigerant flowing through the indoor heat exchange module is more, the compressor 1 has a liquid impact risk, and the opening degree of the throttling assembly is reduced.
In order to improve the accuracy of the opening adjustment of the throttling assembly, dividing a range higher than a target interval into at least two upper limit intervals, wherein each upper limit interval is provided with a corresponding opening adjustment amplitude, and the opening adjustment amplitude of the upper limit interval with higher numerical value is larger; and/or dividing the range lower than the target interval into at least two lower limit intervals, wherein each upper limit interval is provided with a corresponding opening adjustment amplitude, and the opening adjustment amplitude of the lower limit interval with a lower value is larger.
Specifically, the throttle assembly includes an outdoor throttle valve 7 and an indoor throttle valve, the outdoor throttle valve 7 is installed at an outlet side of the outdoor heat exchanger under the refrigeration cycle, and the indoor throttle valve is installed at an inlet side of the indoor heat exchange module under the refrigeration cycle. After the refrigerant circulation loop runs and defrosts and circulates, the outdoor throttle valve 7 is opened to the set maximum opening; when it is determined that the throttle assembly maintains the opening degree, the opening degrees of the outdoor throttle valve 7 and the indoor throttle valve are both maintained unchanged; when the throttle assembly is judged to reduce the opening degree, the opening degree of the outdoor throttle valve 7 is maintained unchanged, and the opening degree of the indoor throttle valve is reduced; when it is determined that the throttle unit increases the opening degree, the opening degree of the outdoor throttle valve 7 is maintained unchanged, and the opening degree of the indoor throttle valve is increased.
Judging whether the operation parameters of the refrigerant circulation loop reach the set defrosting exit conditions or not in the defrosting circulation process; if yes, the defrosting cycle is exited, the compressor 1 is stopped, the four-way valve 4 keeps the on state of the defrosting cycle, the throttling component is opened to the set maximum opening, the refrigerant is continuously transferred into the low-pressure side piping from the high-pressure side where the outdoor heat exchanger 5 is positioned by utilizing the pressure difference between the high-pressure side and the low-pressure side of the system until the operation parameters of the refrigerant circulation loop reach the set four-way valve reversing condition, and the four-way valve 4 is switched to the on state of the heating cycle; if not, maintaining the defrosting cycle.
It should be noted that the "target zone", "upper limit zone" and the like in the above may be obtained through experimental statistics, for example, when the suction superheat is greater than 5 ℃, the indoor throttle valve is adjusted up by 15pls per cycle; the superheat degree of the air suction is 2-5 ℃, and the indoor throttle valve is adjusted up according to 10pls per cycle; the superheat degree of the air suction is equal to 1 ℃, and the indoor throttle valve is maintained to be at the lower opening degree; the superheat degree of the air suction is between minus 1 and 0 ℃, and the indoor throttle valve is adjusted downwards according to 10pls per cycle; the suction superheat is less than 1 ℃, and the indoor throttle valve is adjusted downwards according to 20pls per cycle. The set value may take a constant above 0 ℃, for example 3 ℃. The set defrosting exit condition can be designed to be that the actual defrosting time reaches the set defrosting total time, namely, the refrigerant circulation loop exits the defrosting circulation when the actual defrosting time reaches the set defrosting total time. The reversing condition of the four-way valve can be designed to be that the difference between the discharge side pressure and the suction side pressure of the compressor is reduced to a set pressure difference, namely, when the difference between the discharge side pressure and the suction side pressure of the compressor is reduced to the set pressure difference, the four-way valve is electrified and is switched to the on state of the heating cycle, the compressor is started, and the refrigerant circulation loop operates the heating cycle.
As shown in fig. 4, for the fourth embodiment, the procedure of the control method is as follows.
After the refrigerant circulation loop runs the refrigeration cycle or defrosting cycle, the first end 101 of the switching section and the gas-liquid separator 10 are connected, the second end 102 of the gas-liquid separator 10 is closed, part of refrigerant discharged by the compressor 1 enters the gas-liquid separator 10 to be naturally condensed, the actual liquid storage time of the refrigerant circulation loop running the refrigeration cycle is timed, if the actual liquid storage time is longer than the set liquid storage time, the refrigerant circulation volume in the refrigerant circulation loop is matched with the current mode, the liquid storage of the gas-liquid separator 10 is completed, only the switching section is connected, and the first end 101 and the second end 102 of the gas-liquid separator 10 are closed.
The method comprises the steps of setting the liquid storage time length to be a first liquid storage time length and/or a second liquid storage time length, establishing a corresponding relation between the actual running frequency of a compressor and the limit liquid storage time length through experiments in advance, detecting the actual running frequency of the compressor and obtaining the corresponding limit liquid storage time length from the corresponding relation in the refrigerating cycle or defrosting cycle process, subtracting the set allowance time length from the limit liquid storage time length to obtain the first liquid storage time length, wherein the set allowance time length can be 30 seconds or the like. The second liquid storage time length is calculated according to the performance parameters of the air conditioning system, and the second liquid storage time length t Storage time The calculation formula of (2) is as follows: t is t Storage time Storage capacity of the gas-liquid separator =x (compressor displacement x operating frequency x inlet cross-sectional area of the gas-liquid separator). The sectional area of the inlet pipe of the compressor discharge capacity and the gas-liquid separator is a fixed value, the storage capacity of the gas-liquid separator is the maximum refrigerant quantity A required by the heating cycle of the refrigerant circulation loop minus the maximum refrigerant quantity B required by the refrigeration cycle of the refrigerant circulation loop, and the operating frequency is the target liquid storage frequency of the compressor in the initial stage of the operation refrigeration cycle or defrosting cycle of the refrigerant circulation loop.
After the refrigerant circulation loop enters the refrigeration cycle or the defrosting cycle, the compressor 1 operates at a target liquid storage frequency, the switching section is connected with the first end 101 of the gas-liquid separator 10, the second end 102 of the gas-liquid separator 10 is closed, the actual liquid storage time length of the refrigerant circulation loop in operation refrigeration cycle is counted, the actual liquid storage time length is compared with the first liquid storage time length and the second liquid storage time length in real time, when the actual liquid storage time length is larger than any one of the first liquid storage time length and the first liquid storage time length, the gas-liquid separator finishes liquid storage, only the switching section is connected, the first end 101 and the second end 102 of the gas-liquid separator 10 are closed, and the operation frequency of the compressor 1 is controlled according to the conventional refrigeration cycle or the defrosting cycle.
It should be noted that, in order to avoid excessive storage of the gas-liquid separator, in the model selection stage of the air conditioning system, the gas-liquid separator matching the target storage amount should be selected. In addition, in practical application, the target liquid storage frequency of the refrigeration cycle or the defrosting cycle under different working conditions can be designed in a distinguishing way, the compressor operates according to the target liquid storage frequency corresponding to the current working condition to store liquid at the initial stage of the refrigeration cycle or the defrosting cycle, the first liquid storage duration and the second liquid storage duration are determined according to the target liquid storage frequency, and the target frequency is maintained unchanged until the liquid storage of the gas-liquid separator is completed.
The air conditioning system provided by the invention is suitable for air conditioning units, wherein the air conditioning units comprise, but are not limited to, multiple online units, and the indoor heat exchange module comprises more than two indoor heat exchangers. In order to improve the controllability of the air conditioning system, the outdoor heat exchanger 5 is connected with an indoor heat exchange module through a liquid side pipe, the liquid side pipe is provided with a liquid pipe stop valve 8, the indoor heat exchange module is connected with the four-way valve 4 through a gas side pipe, and the gas side pipe is provided with a gas pipe stop valve 9. In the embodiment in which the storage area is the inner cavity of the gas-liquid separator 10, the first end 101 of the gas-liquid separator 10 is connected to the outlet side of the gas pipe stop valve 9 under the refrigeration cycle, that is, under the refrigeration cycle or the defrosting cycle, the refrigerant flowing out of the outdoor heat exchanger 5 flows through the liquid pipe stop valve 8 before entering the indoor heat exchange module, and the refrigerant flowing out of the indoor heat exchange module flows through the gas pipe stop valve 9 before entering the gas-liquid separator 10.
It is noted that the above-mentioned terms are used merely to describe specific embodiments, and are not intended to limit exemplary embodiments according to the present invention. When the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, the use of the words "first," "second," etc. are used to define elements, for convenience in distinguishing between the corresponding elements. The above "on-off valve", "oil return valve", etc. may employ a solenoid valve, and the "throttle valve" may employ an electronic expansion valve.
Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate. In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.

Claims (20)

1. An air conditioning system comprising: the compressor, the four-way valve, the outdoor heat exchanger, the throttling component and the indoor heat exchange module are sequentially connected to form a refrigerant circulation loop; the refrigerant circulating loop is characterized in that the refrigerant circulating loop is provided with a storage area for temporarily storing liquid refrigerant, and the storage area is connected between the indoor heat exchange module and the four-way valve and is switched and connected to the air suction side or the air discharge side of the compressor through the four-way valve.
2. The air conditioning system of claim 1, wherein the storage area is an interior cavity of a gas-liquid separator, a first end of the gas-liquid separator is connected to an outlet side of the indoor heat exchange module under refrigeration cycle, and a second end of the gas-liquid separator is connected to the four-way valve.
3. The air conditioning system according to claim 2, wherein the refrigerant circulation circuit is further provided with a refrigerant transfer branch circuit with controllable on-off state, an inlet end of the refrigerant transfer pipeline is connected to an outlet side of the outdoor heat exchanger under refrigeration cycle, and an outlet end of the refrigerant transfer pipeline is communicated with an inner cavity of the gas-liquid separator.
4. The air conditioning system according to claim 1, wherein the storage area is a low-pressure side piping in the refrigerant circulation circuit, the low-pressure side piping including: and a connecting pipeline between the indoor heat exchange module and the four-way valve.
5. The air conditioning system according to claim 1, wherein a connecting pipeline between the four-way valve and the outdoor heat exchanger is provided with a switching section, the switching section is connected with a gas-liquid separator, a first end of the gas-liquid separator is connected to one end of the switching section, which is close to the four-way valve, and a second end of the gas-liquid separator is connected to the other end of the switching section, which is close to the outdoor heat exchanger; the gas-liquid separator is characterized in that the first end and the second end of the gas-liquid separator and the on-off state of the switching section are controllable.
6. An air conditioning system according to claim 2, 3 or 5, wherein one of the first end and the second end of the gas-liquid separator, which is connected to the four-way valve, is provided with an oil return hole, or both the first end and the second end are provided with oil return holes, and the oil return holes are close to the bottom of the inner cavity of the gas-liquid separator.
7. An air conditioning system according to claim 2 or 3 or 5, characterized in that the bottom of the inner chamber of the gas-liquid separator is provided with an oil return branch connected to the suction side of the compressor, said oil return branch being provided with an oil return valve and an oil return throttle.
8. An air conditioning unit, characterized in that it employs the air conditioning system according to any one of claims 1 to 7.
9. The air conditioning unit of claim 8, wherein the air conditioning unit is a multi-split air conditioner, and the indoor heat exchange module comprises more than two indoor heat exchangers.
10. A control method of an air conditioning system, the control method being applied to the air conditioning system according to claim 2 or 3; the control method is characterized by comprising the following steps:
after the refrigerant circulation loop performs defrosting circulation, acquiring the superheat degree of the refrigerant at the outlet end of the gas-liquid separator;
judging whether the superheat degree of the refrigerant exceeds a set value;
if yes, the throttle assembly maintains the opening degree;
if not, the throttle assembly reduces the opening degree.
11. The control method according to claim 10, characterized by further comprising: before acquiring the superheat degree of the refrigerant at the outlet end of the gas-liquid separator, timing the actual defrosting time of the defrosting cycle of the refrigerant circulation loop, and if the actual defrosting time reaches a set time threshold t c Acquiring the superheat degree of the refrigerant at the outlet end of the gas-liquid separator; wherein, a time length threshold t is set c <Setting total defrosting duration.
12. The control method of claim 10, wherein the throttle assembly comprises an outdoor throttle valve and an indoor throttle valve;
when the throttle assembly is judged to maintain the opening degree, the opening degrees of the outdoor throttle valve and the indoor throttle valve are maintained unchanged;
when the throttle assembly is determined to reduce the opening degree, the opening degree of the outdoor throttle valve is maintained unchanged, and the opening degree of the indoor throttle valve is reduced.
13. The control method according to claim 10, wherein the refrigerant superheat is T Temperature of outlet pipe -T Low pressure saturation temperature ，T Temperature of outlet pipe T is the actual temperature of the outlet end of the gas-liquid separator Low pressure saturation temperature Is the saturation temperature corresponding to the suction side pressure of the compressor.
14. The control method according to claim 10, characterized by further comprising:
judging whether the operation parameters of the refrigerant circulation loop reach the set defrosting exit conditions or not in the defrosting circulation process;
if yes, the defrosting cycle is exited, the compressor is stopped, the four-way valve keeps the on state of the defrosting cycle, the throttling assembly is closed, and a refrigerant transfer branch between the outdoor heat exchanger and the gas-liquid separator is connected until the operation parameters of the refrigerant cycle loop reach the preset four-way valve reversing condition;
If not, maintaining the defrosting cycle.
15. A control method of an air conditioning system, the control method being applied to the air conditioning system of claim 4; the control method is characterized by comprising the following steps:
after the refrigerant circulation loop is in defrosting circulation, acquiring the suction superheat degree of the compressor;
adjusting the opening of the throttling assembly according to the suction superheat degree of the compressor;
if the suction superheat degree is higher than a target interval, the throttle assembly increases the opening degree;
if the suction superheat degree is in a target interval, the throttle assembly maintains the opening degree;
and if the suction superheat degree is lower than a target interval, the throttle assembly reduces the opening degree.
16. The control method according to claim 15, characterized in that a range higher than the target section is divided into at least two upper limit sections, each of which is provided with a corresponding opening degree adjustment amplitude, the opening degree adjustment amplitude of the upper limit section being larger the higher the value; and/or dividing the range lower than the target interval into at least two lower limit intervals, wherein each upper limit interval is provided with a corresponding opening degree adjusting amplitude, and the opening degree adjusting amplitude of the lower limit interval with a lower numerical value is larger.
17. The control method of claim 15, wherein the throttle assembly comprises an outdoor throttle valve and an indoor throttle valve;
after the refrigerant circulation loop operates for defrosting circulation, the outdoor throttle valve is opened to a set maximum opening;
when the throttle assembly is judged to maintain the opening degree, the opening degrees of the outdoor throttle valve and the indoor throttle valve are maintained unchanged;
when the throttle assembly is judged to reduce the opening degree, the opening degree of the outdoor throttle valve is maintained unchanged, and the opening degree of the indoor throttle valve is reduced;
when the throttle assembly is judged to increase in opening degree, the opening degree of the outdoor throttle valve is kept unchanged, and the opening degree of the indoor throttle valve is increased.
18. The control method according to claim 15, characterized by further comprising:
judging whether the operation parameters of the refrigerant circulation loop reach the set defrosting exit conditions or not in the defrosting circulation process;
if yes, the defrosting cycle is exited, the compressor is stopped, the four-way valve keeps the on state of the defrosting cycle, the throttling component is opened to the set maximum opening degree, and the operation parameters of the refrigerant circulation loop reach the set four-way valve reversing condition;
If not, maintaining the defrosting cycle.
19. A control method of an air conditioning system, the control method being applied to the air conditioning system of claim 5; the control method is characterized by comprising the following steps:
after the refrigerant circulation loop runs the refrigeration cycle or the defrosting cycle, the switching section and the first end of the gas-liquid separator are connected, and the second end of the gas-liquid separator is closed;
the actual liquid storage time of the refrigerant circulation loop operation refrigeration cycle is timed;
if the actual liquid storage time is longer than the set liquid storage time, only the switching section is connected, and the first end and the second end of the gas-liquid separator are closed.
20. The control method according to claim 19, wherein the set liquid storage time period is a first liquid storage time period corresponding to an actual operation frequency of the compressor and/or a second liquid storage time period calculated according to a performance parameter of the air conditioning system, the second liquid storage time period t Storage time The calculation formula of (2) is as follows: t is t Storage time Storage capacity of gas-liquid separator =x (compressor displacement x operating frequency x inlet cross-sectional area of gas-liquid separator);
the storage capacity of the gas-liquid separator is the maximum refrigerant quantity required by the heating cycle of the refrigerant circulation circuit minus the maximum refrigerant quantity required by the refrigeration cycle of the refrigerant circulation circuit, and the operating frequency is the target liquid storage frequency of the compressor at the initial stage of the operation refrigeration cycle or defrosting cycle of the refrigerant circulation circuit.
CN202211542791.1A 2022-12-02 2022-12-02 Air conditioning system, air conditioning unit and control method Pending CN115993016A (en)

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PCT/CN2023/109324 WO2024113911A1 (en) 2022-12-02 2023-07-26 Air conditioning system, air conditioning unit and control method

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