CN113864928A - Air conditioning system and control method thereof - Google Patents

Air conditioning system and control method thereof Download PDF

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Publication number
CN113864928A
CN113864928A CN202111263506.8A CN202111263506A CN113864928A CN 113864928 A CN113864928 A CN 113864928A CN 202111263506 A CN202111263506 A CN 202111263506A CN 113864928 A CN113864928 A CN 113864928A
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China
Prior art keywords
heat exchanger
outdoor
control valve
pipeline
communicated
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CN202111263506.8A
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Chinese (zh)
Inventor
皇甫启捷
吕如兵
梁祥飞
黄泽清
徐璐
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Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
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Priority to CN202111263506.8A priority Critical patent/CN113864928A/en
Publication of CN113864928A publication Critical patent/CN113864928A/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
    • F24F5/00—Air-conditioning systems or apparatus not covered by F24F1/00 or F24F3/00, e.g. using solar heat or combined with household units such as an oven or water heater
    • F24F5/0007—Air-conditioning systems or apparatus not covered by F24F1/00 or F24F3/00, e.g. using solar heat or combined with household units such as an oven or water heater cooling apparatus specially adapted for use in air-conditioning
    • F24F5/001—Compression cycle type
    • 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
    • F24F11/42—Defrosting; Preventing freezing of outdoor units
    • 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
    • F24F11/62—Control or safety arrangements characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
    • F24F11/63—Electronic processing
    • F24F11/64—Electronic processing using pre-stored data
    • 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
    • F24F11/62—Control or safety arrangements characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
    • F24F11/63—Electronic processing
    • F24F11/65—Electronic processing for selecting an operating mode
    • 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
    • F24F11/88—Electrical aspects, e.g. circuits
    • 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
    • F24F2110/10—Temperature
    • F24F2110/12—Temperature of the outside air
    • 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
    • F24F2110/40—Pressure, e.g. wind pressure
    • 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

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  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Fuzzy Systems (AREA)
  • Mathematical Physics (AREA)
  • Human Computer Interaction (AREA)
  • Sustainable Development (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Compression-Type Refrigeration Machines With Reversible Cycles (AREA)

Abstract

The invention provides an air conditioning system and a control method thereof, wherein the air conditioning system comprises: the air conditioning system comprises a first boiling point refrigerant and a second boiling point refrigerant, the boiling point of the first boiling point refrigerant is less than that of the second boiling point refrigerant, one end of the outdoor first heat exchanger can be communicated to an exhaust end or a suction end of the compressor, and the other end of the outdoor first heat exchanger can be communicated to one end of the outdoor second heat exchanger and/or one end of the outdoor third heat exchanger; the other end of the outdoor second heat exchanger and the other end of the outdoor third heat exchanger can be communicated with one end of the indoor heat exchanger after being mixed, and the other end of the indoor heat exchanger can be communicated to a suction end or a discharge end of the compressor. According to the invention, the main condenser does not frost or relieves the frosting speed, and the defrosting and defrosting can be realized while the system stably heats through the alternate work of the 2 auxiliary heat exchangers, so that the comfort of the indoor environment is improved.

Description

Air conditioning system and control method thereof
Technical Field
The invention relates to the technical field of air conditioners, in particular to an air conditioning system and a control method thereof.
Background
When the non-azeotropic working medium is applied to an air conditioning system, from the perspective of system circulation, the non-azeotropic mixed working medium can approach Lorenz circulation in the heat exchange process due to temperature slippage and temperature-enthalpy nonlinear relation in the heat exchange process, so that the circulation efficiency is improved.
Because the conventional air conditioning system in the prior art has the problems of frosting of an outdoor unit and influence on the comfort of indoor environment due to shutdown when defrosting, the air conditioning system and the control method thereof are researched and designed.
Disclosure of Invention
Therefore, the technical problem to be solved by the present invention is to overcome the defects that the outdoor unit is frosted and the shutdown is performed when the outdoor unit is frosted to affect the comfort of the indoor environment in the heating operation of the conventional air conditioning system in the prior art, thereby providing an air conditioning system and a control method thereof.
In order to solve the above problems, the present invention provides an air conditioning system including:
the air conditioning system comprises a compressor, an outdoor first heat exchanger, an outdoor second heat exchanger, an outdoor third heat exchanger, an indoor heat exchanger and a first throttling device, the air conditioning system comprises a first boiling point refrigerant and a second boiling point refrigerant, the boiling point of the first boiling point refrigerant is less than that of the second boiling point refrigerant, one end of the outdoor first heat exchanger can be communicated to a discharge end or a suction end of the compressor, and the other end of the outdoor first heat exchanger can be communicated to one end of the outdoor second heat exchanger and/or one end of the outdoor third heat exchanger;
the other end of the outdoor second heat exchanger is communicated with the other end of the outdoor third heat exchanger and then can be communicated with one end of the first throttling device, the other end of the first throttling device is communicated with one end of the indoor heat exchanger, and the other end of the indoor heat exchanger can be selectively communicated to a suction end or a discharge end of the compressor;
the air conditioning system further comprises an eighth pipeline and a ninth pipeline, one end of the eighth pipeline is communicated with the exhaust end of the compressor, the other end of the eighth pipeline is communicated with the other end of the outdoor second heat exchanger, one end of the ninth pipeline is communicated with the exhaust end of the compressor, the other end of the ninth pipeline is communicated with the other end of the outdoor third heat exchanger, a fifth control valve is arranged on the eighth pipeline, and a sixth control valve is arranged on the ninth pipeline.
In some embodiments, one end of the outdoor first heat exchanger is selectively connectable to a discharge end or a suction end of the compressor through a first line, and the other end is connectable to one end of the outdoor second heat exchanger and/or one end of the outdoor third heat exchanger through a second line, the outdoor second heat exchanger being connected in parallel with the outdoor third heat exchanger.
In some embodiments, the outdoor second heat exchanger is located on a third pipeline, the outdoor third heat exchanger is located on a fourth pipeline, the third pipeline is connected in parallel with the fourth pipeline, one end of the third pipeline is communicated with one end of the fourth pipeline and then communicated with the second pipeline, and the other end of the third pipeline is communicated with the other end of the fourth pipeline and then can be communicated with one end of the indoor heat exchanger.
In some embodiments, a first control valve is disposed on the third pipeline at a position between the outdoor second heat exchanger and the first throttling device, and a second control valve is disposed on the fourth pipeline at a position between the outdoor third heat exchanger and the first throttling device;
and a third control valve is arranged on the third pipeline and between the outdoor second heat exchanger and the outdoor first heat exchanger, and a fourth control valve is arranged on the fourth pipeline and between the outdoor third heat exchanger and the outdoor first heat exchanger.
In some embodiments, the system further comprises a tenth pipeline and an eleventh pipeline, the tenth pipeline is arranged on the third control valve in parallel, the tenth pipeline is further provided with a second throttling device, the eleventh pipeline is arranged on the fourth control valve in parallel, and the eleventh pipeline is further provided with a third throttling device.
In some embodiments, the compressor further comprises a fifth pipeline, a sixth pipeline and a seventh pipeline, the third pipeline and the fourth pipeline are merged and then communicated to one end of the first throttling device through the fifth pipeline, the other end of the first throttling device is communicated to one end of the indoor heat exchanger through the sixth pipeline, and the other end of the indoor heat exchanger is communicated to a suction end or a discharge end of the compressor through the seventh pipeline.
In some embodiments, the air conditioner further comprises a four-way valve, the four-way valve comprises an E end, an S end, a C end and a D end, the E end is communicated with the seventh pipeline, the S end is communicated with the air suction end of the compressor, the C end is communicated with the first pipeline, the D end is communicated with the air discharge end of the compressor, and the first communication state of the four-way valve is as follows: the end E is communicated with the end S, the end C is communicated with the end D, at the moment, the indoor operation is in a refrigerating state, and the second communication state of the four-way valve is as follows: the end E is communicated with the end D, the end S is communicated with the end C, and at the moment, the indoor operation is in a heating state; the four-way valve can be switched between the first communication state and the second communication state.
In some embodiments, the outdoor heat exchanger further comprises a first fan, wherein the first fan can drive the outdoor air flow to partially flow through the outdoor first heat exchanger, partially flow through the outdoor second heat exchanger, and partially flow through the outdoor third heat exchanger;
the indoor heat exchanger is characterized by further comprising a second fan, and the second fan can drive indoor airflow to flow through the indoor heat exchanger.
The present invention also provides a method for controlling an air conditioning system as described in any one of the above, comprising:
detecting the operation mode of an air conditioning system, the temperature Tout of an outdoor environment and the refrigerant inlet temperature Tin of the outdoor second heat exchanger or the outdoor third heat exchanger in a heating mode;
a judging step, namely judging the relation between Tout and a first preset value T1, and judging the relation between Tin and a second preset value T2 and a third preset value T3; wherein T2 > T3;
a control step, when further comprising a first control valve and a second control valve:
when the air conditioner is operated in the cooling mode: controlling both the first control valve and the second control valve to open; when the air conditioner operates in the heating mode: when Tout is larger than or equal to T1 and Tin is larger than or equal to T2, controlling the first control valve and the second control valve to be opened; and when Tout is larger than or equal to T1 and lasts for time Tin < T3 within T1, or when Tout is smaller than T1 and continues for time Tin < T2 within T1, one of the first control valve and the second control valve is controlled to be opened, and the other control valve is controlled to be closed, wherein T1 is a first preset time.
In some embodiments, in the controlling step, when the air conditioner is operated in the heating mode, and when Tout is larger than or equal to T1 and Tin is less than T3 within a continuous time T1, or when Tout is less than T1 and Tin is less than T2 within a continuous time T1, the first control valve is controlled to be opened, the second control valve is controlled to be closed, and after the time T2, T2 is a second preset time;
in the step of detecting, the air inlet pressure and the air outlet pressure of the outdoor second heat exchanger can be detected;
in the judging step, whether a first pressure difference between the air inlet pressure and the air outlet pressure of the outdoor second heat exchanger is greater than or equal to a first preset pressure difference value or not can be judged;
the control step can also be carried out when the first pressure difference is larger than or equal to the first preset pressure difference, the first control valve is controlled to be closed, and the second control valve is controlled to be opened; and when the first pressure difference is smaller than the first preset pressure difference, the first control valve is kept to be opened, and the second control valve is kept to be closed.
In some embodiments, when further comprising a third control valve, a fourth control valve, a fifth control valve, a sixth control valve, a second throttling device, and a third throttling device:
in the control step, when the first pressure difference is greater than or equal to the preset pressure difference, the first control valve is controlled to be closed, and the second control valve is controlled to be opened, the fifth control valve is opened, the sixth control valve is closed, the fourth control valve is opened, the third control valve is closed, the second throttling device is opened, and the third throttling device is closed, so that the outdoor second heat exchanger is heated and defrosted.
In some embodiments, in the controlling step, when the air conditioner is operated in the heating mode, and when Tout is larger than or equal to T1 and Tin is less than T3 within a continuous time T1, or when Tout is less than T1 and Tin is less than T2 within a continuous time T1, the first control valve is controlled to be closed, the second control valve is controlled to be opened, and after the time T2, T2 is a second preset time;
in the step of detecting, the air inlet pressure and the air outlet pressure of the outdoor third heat exchanger can be detected;
in the judging step, whether a second pressure difference between the air inlet pressure and the air outlet pressure of the outdoor third heat exchanger is greater than or equal to a second preset pressure difference value can be judged;
in the control step, when the second pressure difference is greater than or equal to the second preset pressure difference, the first control valve is controlled to be opened, and the second control valve is controlled to be closed; and when the second pressure difference is smaller than the second preset pressure difference, the first control valve is kept closed, and the second control valve is kept opened.
In some embodiments, when further comprising a third control valve, a fourth control valve, a fifth control valve, a sixth control valve, a second throttling device, and a third throttling device:
in the control step, when the second pressure difference is greater than or equal to the second preset pressure difference, the first control valve is controlled to be opened, and the second control valve is controlled to be closed, the fifth control valve is closed, the sixth control valve is opened, the fourth control valve is closed, the third control valve is opened, the second throttling device is closed, and the third throttling device is opened, so that the third outdoor heat exchanger is heated and defrosted.
In some embodiments, T3 < T2 < T1; when the air conditioning system further comprises a four-way valve, a third control valve, a fourth control valve, a fifth control valve and a sixth control valve:
the control step can also be carried out when the air conditioner operates in a heating mode: and when Tout is less than T4, the first control valve and the second control valve are controlled to be opened, and the four-way valve is controlled to be reversed and switched to a cooling mode to defrost at least one of the outdoor first heat exchanger, the outdoor second heat exchanger and the outdoor second heat exchanger, wherein T4 is less than T3.
The air conditioning system and the control method thereof provided by the invention have the following beneficial effects:
1. the system adopts the non-azeotropic working medium, fully utilizes the temperature slip characteristic of the non-azeotropic working medium, simultaneously divides the outdoor heat exchanger into three parts (a main heat exchanger and two auxiliary heat exchangers, wherein the main heat exchanger and the auxiliary heat exchangers are arranged in series on the windward area, and the two auxiliary heat exchangers are arranged in parallel on the flow direction), sacrifices a small part of heat exchange area, and ensures that the main heat exchange area is not frosted. During heating operation, a refrigerant enters from one end of one auxiliary heat exchanger, a low-boiling-point refrigerant is evaporated in the auxiliary heat exchanger firstly, the surface temperature of the low-boiling-point refrigerant is low, and the low-boiling-point refrigerant is easy to frost. When an auxiliary heat exchanger defrosts, another auxiliary heat exchanger work through 2 auxiliary heat exchangers's work in turn for the system can also realize defrosting, the function of defrosting when steadily heating, improves the travelling comfort of indoor environment. The invention can communicate the eighth pipeline and the ninth pipeline to the exhaust end of the compressor, so that when one of the auxiliary heat exchangers needs defrosting, the auxiliary heat exchanger is effectively defrosted by introducing the high-temperature and high-pressure refrigerant exhausted by the compressor, and the defrosting and defrosting efficiency is improved;
drawings
FIG. 1 is a schematic diagram of the non-azeotropic working medium system cycle (refrigeration mode) of the main embodiment of the present invention;
FIG. 2 is a schematic diagram of the non-azeotropic working medium system cycle (general heating mode) of the main embodiment of the present invention;
FIG. 3 is a schematic diagram of the non-azeotropic working medium system cycle (low temperature heating) in the main embodiment of the present invention;
FIG. 4 is a schematic diagram of the circulation of a non-azeotropic working medium system according to the main embodiment of the present invention (heating under low temperature and defrosting in the windward 21a at the same time);
FIG. 5 is a schematic diagram of the non-azeotropic working medium system cycle of the main embodiment of the present invention (low temperature heating and defrosting in the windward 21a is completed);
fig. 6 is a schematic diagram of the circulation of the non-azeotropic working medium system according to the main embodiment of the present invention (low temperature heating and defrosting by the leeward 21a (i.e. defrosting by the windward 21 b)).
The reference numerals are represented as:
10. a compressor; 21. an outdoor first heat exchanger; 21a, an outdoor second heat exchanger; 21b, an outdoor third heat exchanger; 31. a first throttling device; 32. a second throttling device; 33. a third throttling means; 41. an indoor heat exchanger; 51. a four-way valve; E. an E end; s, S end; C. a C terminal; D. a D end; 61. a first fan; 62. a second fan; 71. a first control valve; 72. a second control valve; 73. a third control valve; 74. a fourth control valve; 75. a fifth control valve; 76. a sixth control valve;
101. a first pipeline; 102. a second pipeline; 103. a third pipeline; 104. a fourth pipeline; 105. a fifth pipeline; 106. a sixth pipeline; 107. a seventh pipeline; 108. an eighth pipeline; 109. a ninth conduit; 110. a tenth pipeline; 111. an eleventh line.
Detailed Description
Primary embodiment, as shown in fig. 1-6, the present invention provides an air conditioning system comprising:
the air conditioning system comprises a compressor 10, an outdoor first heat exchanger 21, an outdoor second heat exchanger 21a, an outdoor third heat exchanger 21b, an indoor heat exchanger 41 and a first throttling device 31, the air conditioning system comprises a first boiling point refrigerant and a second boiling point refrigerant, the boiling point of the first boiling point refrigerant is less than that of the second boiling point refrigerant, one end of the outdoor first heat exchanger 21 can be communicated to a discharge end or a suction end of the compressor 10, and the other end of the outdoor first heat exchanger 21 can be communicated to one end of the outdoor second heat exchanger 21a and/or one end of the outdoor third heat exchanger 21 b;
the other end of the outdoor second heat exchanger 21a is communicated with the other end of the outdoor third heat exchanger 21b and then can be communicated with one end of the first throttling device 31, the other end of the first throttling device 31 is communicated with one end of the indoor heat exchanger 41, and the other end of the indoor heat exchanger 41 can be selectively communicated to a suction end or a discharge end of the compressor 10;
the air conditioning system further comprises an eighth pipeline 108 and a ninth pipeline 109, wherein one end of the eighth pipeline 108 is communicated with the exhaust end of the compressor 10, the other end of the eighth pipeline is communicated with the other end of the outdoor second heat exchanger 21a, one end of the ninth pipeline 109 is communicated with the exhaust end of the compressor 10, the other end of the ninth pipeline 109 is communicated with the other end of the outdoor third heat exchanger 21b, the eighth pipeline 108 is provided with a fifth control valve 75, and the ninth pipeline 109 is provided with a sixth control valve 76.
The system adopts the non-azeotropic working medium, fully utilizes the temperature slip characteristic of the non-azeotropic working medium, simultaneously divides the outdoor heat exchanger into three parts (a main heat exchanger and two auxiliary heat exchangers, wherein the main heat exchanger and the auxiliary heat exchangers are arranged in series on the windward area, and the two auxiliary heat exchangers are arranged in parallel on the flow direction), sacrifices a small part of heat exchange area, and ensures that the main heat exchange area is not frosted. The refrigerant enters from one end of one auxiliary heat exchanger, the low-boiling-point refrigerant is firstly evaporated in the auxiliary heat exchanger, the surface temperature of the low-boiling-point refrigerant is low, and the low-boiling-point refrigerant is easy to frost. When an auxiliary heat exchanger defrosts, another auxiliary heat exchanger work through 2 auxiliary heat exchangers's work in turn for the system can also realize defrosting, the function of defrosting when steadily heating, improves the travelling comfort of indoor environment. In addition, the invention can communicate the eighth pipeline and the ninth pipeline to the exhaust end of the compressor, so that when one auxiliary heat exchanger needs defrosting, the auxiliary heat exchanger is effectively defrosted by introducing the high-temperature and high-pressure refrigerant exhausted by the compressor, and the defrosting and defrosting efficiency is improved.
1. The invention is different from the conventional refrigeration system, the proposal adopts the non-azeotropic refrigerant with large slip temperature, the slip temperature is more than 5 ℃ and less than the temperature difference of inlet and outlet air;
2. the invention solves the problems of system performance reduction and indoor environment comfort reduction caused by frosting during heating operation of the air conditioning system.
The air conditioning system shown in fig. 1 includes a compressor 10, an outdoor first heat exchanger 21, an outdoor second heat exchanger 21a, an outdoor third heat exchanger 21b, a first throttle device 31, an indoor heat exchanger 41, a four-way valve 51, a first fan 61, a second fan 62, a first control valve 71, a second control valve 72, and preferably a two-way valve.
The system circularly adopts non-azeotropic refrigerants, and the standard boiling points of the non-azeotropic refrigerants have certain difference, so that the non-azeotropic refrigerants can have different heat exchange characteristics from pure working media (or near-azeotropic working media) in the heat exchange process. In the evaporation process, the evaporation temperature of the non-azeotropic refrigerant is gradually increased, and the temperature of the external heat exchange fluid (air or water) is gradually reduced; in the same way, in the condensation process, the temperature of the non-azeotropic refrigerant is gradually reduced, and the temperature of the heat exchange fluid (air or water) is gradually increased, so that the heat exchange fluid is applied to a scene of heating and defrosting, and has a remarkable effect of inhibiting the frosting of the heat exchanger to cause the performance reduction of the system.
In some embodiments, one end of the outdoor first heat exchanger 21 is selectively connectable to a discharge end or a suction end of the compressor 10 through a first pipe 101, and the other end is connected to one end of the outdoor second heat exchanger 21a and/or one end of the outdoor third heat exchanger 21b through a second pipe 102, and the outdoor second heat exchanger 21a is connected in parallel with the outdoor third heat exchanger 21 b. The first outdoor heat exchanger, the second outdoor heat exchanger and the third outdoor heat exchanger are preferably arranged, the first outdoor heat exchanger is connected with the second outdoor heat exchanger and/or the third outdoor heat exchanger in series, and the second outdoor heat exchanger is connected with the third outdoor heat exchanger in parallel, so that defrosting and defrosting can be realized by sacrificing a small part of heat exchange area. When in heating operation, 3 heat exchangers are arranged outdoors and are all used as evaporators. The non-azeotropic working medium has the temperature gradually increased in the heat exchange process in the evaporator due to the temperature slip characteristic, so that the evaporation temperature of the refrigerant in the small heat exchanger is lower than the dew point temperature of the outdoor working condition, the outdoor small heat exchanger frosts, the temperature of the refrigerant coming out of the outdoor second heat exchanger 21a is higher than the dew point temperature due to the temperature slip characteristic, and then the refrigerant enters the outdoor first heat exchanger 21 for heat exchange, and the temperature of the refrigerant exchanging heat in the refrigerant is higher than the dew point temperature and lower than the outdoor dry bulb temperature, so that the outdoor first heat exchanger cannot frost. When the frost layer of the outdoor second heat exchanger 21a is built up to a certain extent, the outdoor third heat exchanger 21b is caused to operate in place of the outdoor second heat exchanger 21 a. So as to realize frosting and defrosting in turn without stopping the machine.
In some embodiments, the outdoor second heat exchanger 21a is located on a third pipeline 103, the outdoor third heat exchanger 21b is located on a fourth pipeline 104, the third pipeline 103 is connected in parallel with the fourth pipeline 104, one end of the third pipeline 103 is communicated with one end of the fourth pipeline 104 and then communicated with the second pipeline 102, and the other end of the third pipeline 103 is communicated with the other end of the fourth pipeline 104 and then communicated with one end of the indoor heat exchanger 41.
The first pipeline can lead the compressor exhaust gas to the outdoor first heat exchanger 21 for condensation and heat release in the refrigeration mode, and can lead the refrigerant coming out of the outdoor first heat exchanger back to the suction end of the compressor in the heating mode; the second pipeline can be used for leading-in to outdoor first heat exchanger after the refrigerant that comes with the third pipeline and fourth pipeline mixes under the heating mode, and the third pipeline and fourth pipeline are used for connecting outdoor second heat exchanger and outdoor third heat exchanger in parallel respectively to select to open two heat exchangers or only open a heat exchanger according to the operating mode condition of difference, in order to realize the effect of defrosting.
In some embodiments, a first control valve 71 is disposed on the third pipeline 103 at a position between the outdoor second heat exchanger 21a and the first throttling device 31, and a second control valve 72 is disposed on the fourth pipeline 104 at a position between the outdoor third heat exchanger 21b and the first throttling device 31;
a third control valve 73 is disposed on the third pipeline 103 and between the outdoor second heat exchanger 21a and the outdoor first heat exchanger 21, and a fourth control valve 74 is disposed on the fourth pipeline 104 and between the outdoor third heat exchanger 21b and the outdoor first heat exchanger 21.
Whether the outdoor second heat exchanger and the indoor third heat exchanger are connected or not can be controlled through a first control valve arranged on a third pipeline communicated with the outdoor second heat exchanger and a second control valve arranged on a fourth pipeline communicated with the outdoor third heat exchanger; can select to open two heat exchangers or only open a heat exchanger according to the operating mode condition of difference to the effect of defrosting is realized. Whether the outdoor second heat exchanger is communicated with the outdoor first heat exchanger or not can be controlled through the third control valve, whether the outdoor third heat exchanger is communicated with the outdoor first heat exchanger or not is controlled through the fourth control valve, and therefore whether the outdoor second heat exchanger is communicated with the outdoor first heat exchanger or not is controlled, and whether the outdoor third heat exchanger is communicated with the outdoor first heat exchanger or not is controlled.
In some embodiments, the system further comprises a tenth pipeline 110 and an eleventh pipeline 111, the tenth pipeline 110 is connected to the third control valve 73 in parallel, the tenth pipeline 110 is further provided with a second throttling device 32, the eleventh pipeline 111 is connected to the fourth control valve 74 in parallel, and the eleventh pipeline 111 is further provided with a third throttling device 33. The invention also provides a tenth pipeline and an eleventh pipeline, wherein the tenth pipeline can be connected in parallel with a pipeline where the third control valve is located, the eleventh pipeline is connected in parallel with a pipeline where the fourth control valve is located, the tenth pipeline and the eleventh pipeline are respectively provided with a second throttling device and a third throttling device, when the pipeline where the control valve is located is closed, the pipeline where the throttling devices are located is opened, the throttling and pressure reducing are carried out on the refrigerant which is subjected to air exhaust and defrosting of the compressor, after the air exhaust of the compressor is utilized to heat and defrost the outdoor second heat exchanger or the outdoor third heat exchanger, the throttling and pressure reducing are carried out through the auxiliary throttling device, and the refrigerant further reaches the outdoor first heat exchanger to be evaporated and absorb heat, so that an effective refrigeration cycle process is formed.
In some embodiments, the air conditioner further comprises a fifth pipeline 105, a sixth pipeline 106 and a seventh pipeline 107, the third pipeline 103 is merged with the fourth pipeline 104 and communicated to one end of the first throttling device 31 through the fifth pipeline 105, the other end of the first throttling device 31 is communicated to one end of the indoor heat exchanger 41 through the sixth pipeline 106, and the other end of the indoor heat exchanger 41 is communicated to the suction end or the exhaust end of the compressor 10 through the seventh pipeline 107. The second outdoor heat exchanger and the third outdoor heat exchanger can be effectively communicated with the indoor heat exchanger through the fifth pipeline and the sixth pipeline, the throttling and pressure reducing effects can be performed on indoor and outdoor refrigerants through the throttling device, the seventh pipeline can be used for communicating the indoor heat exchanger with the compressor, the indoor heat exchanger is communicated with the suction end of the compressor in the cooling mode, and the indoor heat exchanger is communicated with the exhaust end of the compressor in the heating mode.
In some embodiments, further comprises a four-way valve 51, the four-way valve comprises an E-end E, S end S, C end C and a D-end D, the E-end E is communicated with the seventh pipeline 107, the S-end S is communicated with the suction end of the compressor 10, the C-end C is communicated with the first pipeline 101, the D-end D is communicated with the discharge end of the compressor 10, and the first communication state of the four-way valve is: the E end E is communicated with the S end S, the C end C is communicated with the D end D, at the moment, the indoor operation is in a refrigerating state, and the second communication state of the four-way valve is as follows: the E end E is communicated with the D end D, the S end S is communicated with the C end C, and at the moment, the indoor operation is in a heating state; the four-way valve 51 is switchable between the first communication state and the second communication state. The indoor heat exchanger, the outdoor heat exchanger and the compressor can be connected into an integral system through the four-way valve, and can be switched to realize switching control between a cooling mode and a heating mode.
In some embodiments, the air conditioner further comprises a first fan 61, wherein the first fan 61 can drive the outdoor air to partially flow through the outdoor first heat exchanger 21, partially flow through the outdoor second heat exchanger 21a, and partially flow through the outdoor third heat exchanger 21 b;
and a second fan 62, wherein the second fan 62 can drive the indoor airflow to flow through the indoor heat exchanger 41.
According to the invention, through the arrangement of the first fan, outdoor airflow can be driven to enter the outdoor first heat exchanger, the outdoor second heat exchanger and the outdoor third heat exchanger for heat exchange, and through the arrangement of the second fan, indoor airflow can be driven to enter the indoor heat exchanger for heat exchange.
The present invention also provides a method for controlling an air conditioning system as described in any one of the above, comprising:
detecting the operation mode of the air conditioning system, the temperature Tout of the outdoor environment and the inlet temperatures Tin of the outdoor second heat exchanger and the outdoor third heat exchanger, wherein Tin refers to the inlet temperatures of the outdoor second heat exchanger and the outdoor third heat exchanger in the heating mode;
a judging step, namely judging the relation between Tout and a first preset value T1, and judging the relation between Tin and a second preset value T2 and a third preset value T3; wherein T2 > T3;
control step, when further comprising a first control valve 71 and a second control valve 72:
when the air conditioner is operated in the cooling mode: controlling both the first control valve 71 and the second control valve 72 to open; when the air conditioner operates in the heating mode: when Tout is larger than or equal to T1 and Tin is larger than or equal to T2, the first control valve 71 and the second control valve 72 are controlled to be opened; and when Tout is larger than or equal to T1 and lasts for time Tin < T3 within T1, or when Tout is smaller than T1 and continues for time Tin < T2 within T1, one of the first control valve 71 and the second control valve 72 is controlled to be opened, and the other is controlled to be closed, wherein T1 is a first preset time.
The system adopts the non-azeotropic working medium, fully utilizes the temperature slippage characteristic of the non-azeotropic working medium, and simultaneously divides the outdoor heat exchanger into three parts (a main heat exchanger and two auxiliary heat exchangers, wherein the main heat exchanger and the auxiliary heat exchangers are arranged in series on the windward area, and the two auxiliary heat exchangers are arranged in parallel on the flow direction), so that a small part of heat exchange area is sacrificed, and the main heat exchange area is not frosted. The refrigerant enters from one end of one auxiliary heat exchanger, the low-boiling-point refrigerant is firstly evaporated in the auxiliary heat exchanger, the surface temperature of the low-boiling-point refrigerant is low, and the low-boiling-point refrigerant is easy to frost. When an auxiliary heat exchanger defrosts, another auxiliary heat exchanger work through 2 auxiliary heat exchangers's work in turn for the system can also realize defrosting, the function of defrosting when steadily heating, improves the travelling comfort of indoor environment.
Generally, for pure working medium refrigerants, when the evaporation temperature is lower than 0 ℃, an outdoor heat exchanger is easy to frost, and a frost layer is thicker and thicker on the surface of an outdoor evaporator, and the heat exchange is worse and worse, so that a good heating effect cannot be achieved, and even shutdown occurs. However, as for the non-azeotropic working medium, the temperature slip characteristic exists, and the evaporation temperature is gradually increased in the heat exchange process, so that the evaporation temperature at the inlet of the evaporator is low, and the frosting is very easy to occur.
The invention utilizes the characteristics of the non-azeotropic working medium to divide the outdoor heat exchanger into three parts, so that during heating operation, the frosting part only occurs on the two auxiliary heat exchangers, and the frosting of the main heat exchanger is avoided or delayed, thereby ensuring that the heating process can still be normally carried out. The two auxiliary heat exchangers run alternately in frosting and defrosting mode, and the main heat exchanger runs normally all the time.
1. The invention is different from the conventional refrigeration system, the proposal adopts the non-azeotropic refrigerant with large slip temperature, the slip temperature is more than 5 ℃ and less than the temperature difference of inlet and outlet air;
2. the invention solves the problems of system performance reduction and indoor environment comfort reduction caused by frosting during heating operation of the air conditioning system.
The air conditioning system shown in fig. 1 includes a compressor 10, an outdoor first heat exchanger 21, an outdoor second heat exchanger 21a, an outdoor third heat exchanger 21b, a first throttle device 31, an indoor heat exchanger 41, a four-way valve 51, a first fan 61, a second fan 62, a first control valve 71, a second control valve 72, and preferably a two-way valve.
The system circularly adopts non-azeotropic refrigerants, and the standard boiling points of the non-azeotropic refrigerants have certain difference, so that the non-azeotropic refrigerants can have different heat exchange characteristics from pure working media (or near-azeotropic working media) in the heat exchange process. In the evaporation process, the evaporation temperature of the non-azeotropic refrigerant is gradually increased, and the temperature of the external heat exchange fluid (air or water) is gradually reduced; in the same way, in the condensation process, the temperature of the non-azeotropic refrigerant is gradually reduced, and the temperature of the heat exchange fluid (air or water) is gradually increased, so that the heat exchange fluid is applied to a scene of heating and defrosting, and has a remarkable effect of inhibiting the frosting of the heat exchanger to cause the performance reduction of the system, and the specific implementation mode is as follows:
1. in the cooling mode, as shown in fig. 1, the first control valve 71, the second control valve 72, the third control valve 73, and the fourth control valve 74 are all opened; while the fifth control valve 75, the sixth control valve 76, the second throttle device 32 and the third throttle device 73 are all closed.
The high-temperature and high-pressure refrigerant discharged by the compressor 10 enters the outdoor first heat exchanger 21, is divided into two paths after heat exchange in the outdoor first heat exchanger 21 is completed, and respectively enters the outdoor second heat exchanger 21a and the outdoor third heat exchanger 21b, then the two paths of refrigerant are mixed, the mixed refrigerant is throttled and depressurized by the first throttling device 31 and then enters the indoor heat exchanger 41, and enters the suction port of the compressor 10 through the four-way valve 51 after heat exchange is completed, and is compressed into a high-temperature and high-pressure state in the compressor, so that the whole refrigeration cycle is completed.
2. The heating mode is divided into three conditions, namely general heating working condition, low-temperature heating working condition and severe working condition heating, and defrosting are needed under the low-temperature heating working condition. The control system of the air conditioner detects the temperature Tout of the outdoor environment and the inlet temperature Tin of the outdoor heat exchanger, if Tout is more than 5 ℃ and Tin is more than 0 ℃, the outdoor heat exchanger cannot frost, and the system operates in a general heating mode; if Tout < 5 ℃ is detected and Tin < 0 ℃ is detected for one minute or Tout > 5 ℃ and Tin < 2 ℃ is detected, then frosting at the inlet of the outdoor heat exchanger is indicated. The specific operation mode is as follows:
2.1, the detection device detects that Tout is more than 5 ℃ and Tin is more than 0 ℃, and a common heating mode is operated, wherein the first control valve 71 and the second control valve 72 are both communicated, and the third control valve 73 and the fourth control valve 74 are both communicated; while the fifth control valve 75, the sixth control valve 76, the second throttle device 32 and the third throttle device 73 are all closed, as shown in fig. 2.
The high-temperature and high-pressure refrigerant discharged by the compressor 10 enters the indoor first heat exchanger 41 through the D, E pipe of the four-way valve, after heat exchange is completed, the refrigerant is throttled and depressurized by the first throttling device 31, then is divided into two paths, and enters the outdoor second heat exchanger 21a and the outdoor third heat exchanger 21b through the first control valve 71 and the second control valve 72 respectively for heat exchange, after heat exchange is completed, the two paths of refrigerants are mixed, the mixed refrigerant enters the outdoor first heat exchanger 21 for heat exchange, finally enters the suction port of the compressor 10 through the C, S pipe of the four-way valve 51, and is compressed into a high-temperature and high-pressure state in the compressor, so that the whole heating cycle is completed.
2.2 when the detecting device detects Tout is more than 5 ℃ and Tin is less than-2 ℃ continuously for one minute, or Tout is less than 5 ℃ and Tin is less than 0 ℃ continuously for one minute, the frosting is easy to occur at the inlet of the outdoor preferable heat exchanger, and the low-temperature heating mode needs to be operated, firstly, the first control valve 71 is conducted, the second control valve 72 is closed, meanwhile, the third control valve 73 is conducted, the fourth control valve 74, the fifth control valve 75 and the sixth control valve 76 are closed, the second throttling device 32 and the third throttling device 33 are closed, and at this time, the system operates the low-temperature heating mode. When the micro differential pressure gauge detects that the air inlet and outlet pressure difference of the outdoor second heat exchanger 21a is increased to a certain value, which indicates that the surface of the outdoor second heat exchanger 21a is frosted and needs to be defrosted, the outdoor third heat exchanger 21b is used for replacing the outdoor second heat exchanger 21a to work, at this time, the first control valve 71 is closed, the second control valve 72 is conducted, meanwhile, the third control valve 73 and the sixth control valve 76 are closed, the fourth control valve 74 and the fifth control valve 75 are conducted, the second throttling device 32 is opened, and the third throttling device 33 is closed, and the specific real-time mode is as follows:
a) first, the first control valve 71 is opened, the second control valve 72 is closed, the third control valve 73 is opened, the fourth control valve 74, the fifth control valve 75 and the sixth control valve 76 are all closed, the first throttling device 31 is opened, and the second throttling device 32 and the third throttling device 33 are closed (valve-closed no-flow) as shown in fig. 3:
the high-temperature and high-pressure refrigerant discharged from the compressor 10 enters the indoor heat exchanger 41 through the D, E pipe of the four-way valve for heat exchange, then is throttled and depressurized by the first throttling device 31, then sequentially passes through the outdoor second heat exchanger 21a and the outdoor first heat exchanger 21, enters the suction port of the compressor 10 through the C, S pipe of the four-way valve 51 after heat exchange is completed, and is compressed to complete the whole cycle.
In this mode, because the temperature of the outdoor environment is low, the inlet temperature Tin of the outdoor second heat exchanger 21a is lower than the dew point temperature of the outdoor environment, so that the evaporator of the outdoor second heat exchanger 21a is prone to frosting, but due to the temperature slip characteristic of the non-azeotropic working medium, the temperature of the refrigerant in the outdoor second heat exchanger 21a gradually increases along the process direction, and the temperature of the refrigerant at the outlet of the outdoor second heat exchanger 21a is ensured to be higher than the dew point temperature of the outdoor environment and lower than the dry bulb temperature of the outdoor environment through the previous heat exchanger matching, so that when the refrigerant enters the outdoor first heat exchanger 21 for heat exchange, the outdoor first heat exchanger 21 cannot frost, and the stable operation of the heating process is ensured. Meanwhile, as the heat exchange is continuously performed, the frost layer on the surface of the outdoor second heat exchanger 21a becomes thicker and thicker, and when the differential pressure of the inlet air and the outlet air of the outdoor second heat exchanger 21a is detected to be increased to a certain value by the micro differential pressure gauge, it is described that the frost layer is thicker at this time, which affects the heat exchange performance of the heat exchanger, and the defrosting process needs to be performed on the outdoor second heat exchanger 21a, the first control valve 71 and the third control valve 73 need to be closed, the second control valve 72 and the fourth control valve 74 need to be opened, the fifth control valve 75 needs to be opened, the sixth control valve 76 needs to be closed, the second throttling device 32 needs to be opened, the third throttling device 33 needs to be closed, and the outdoor third heat exchanger 21b works. The outdoor second heat exchanger 21a performs defrosting by introducing high-temperature and high-pressure exhaust gas.
In some embodiments, in the controlling step, when the air conditioner is operated in the heating mode, and when Tout is greater than or equal to T1 and Tin is less than T3 for a continuous time T1, or when Tout is less than T1 and Tin is less than T2 for a continuous time T1, the first control valve 71 is controlled to be opened, the second control valve 72 is controlled to be closed, and after the time T2, the time T2 is a second preset time; t3 is preferably-2 ℃, T2 is preferably 0 ℃ and T1 is preferably 5 ℃.
In the detecting step, the air inlet pressure and the air outlet pressure of the outdoor second heat exchanger 21a can also be detected;
in the judging step, whether a first pressure difference between the air inlet pressure and the air outlet pressure of the outdoor second heat exchanger 21a is greater than or equal to a first preset pressure difference value or not can be judged;
in the control step, when the first pressure difference is greater than or equal to the first preset pressure difference, the first control valve 71 is controlled to be closed, and the second control valve 72 is controlled to be opened; when the first pressure difference is smaller than the first preset pressure difference, the first control valve 71 is maintained to be opened, and the second control valve 72 is maintained to be closed.
In some embodiments, the controlling step is further configured to open the fifth control valve 75, close the sixth control valve 76, simultaneously open the fourth control valve 74, close the third control valve 73, simultaneously open the second throttling device 32, close the second throttling device 33, and heat and defrost the outdoor second heat exchanger 21a when the first pressure difference is greater than or equal to the preset pressure difference and the first control valve 71 is controlled to be closed and the second control valve 72 is controlled to be open.
b) The first control valve 71 is closed, the second control valve 72 is opened, the third control valve 73 is closed, the fourth control valve 74 and the fifth control valve 75 are opened, the sixth control valve 76 is closed, the first throttling device 31 and the second throttling device 32 are opened, and the third throttling device 33 is closed (valve-closed no-flow) as shown in fig. 4:
when the frost layer of the outdoor second heat exchanger 21a reaches a certain thickness, it is necessary to switch to this state, and its specific operation mode is slightly different from the above operation mode. Namely, the high-temperature and high-pressure refrigerant discharged from the compressor 10 is divided into two paths, wherein one path of refrigerant enters the indoor heat exchanger 41 for heat exchange (at this time, the temperature of the refrigerant is higher) through the D, E pipe of the four-way valve, then is throttled and depressurized through the first throttling device 31, and enters the outdoor third heat exchanger 21b for heat exchange through the second control valve 72; and the other path of refrigerant enters the outdoor second heat exchanger 21a through the fifth control valve 75 to heat the outdoor second heat exchanger 21a, so that the frost layer on the surface of the outdoor second heat exchanger 21a is melted (at this time, the outdoor second heat exchanger 21a is equivalent to a low-temperature condenser), the refrigerant after heat exchange in the outdoor second heat exchanger 21a is throttled and depressurized through the second throttling device 32 and is mixed with the refrigerant coming out of the outdoor third heat exchanger 21b, the mixed refrigerant enters the outdoor first heat exchanger 21 to exchange heat, and enters the air suction port of the compressor 10 through the C, S pipe of the four-way valve after heat exchange is finished, and the whole cycle is finished after the refrigerant is compressed.
With the circulation, the frost layer on the surface of the outdoor second heat exchanger 21a is gradually melted, and when the defrosting mode is continuously operated for 8mins and the pipe wall temperature Twa of the outdoor second heat exchanger 21a is detected to be more than or equal to 10 ℃, the defrosting mode is ended, and the fifth control valve 75 is closed, as shown in fig. 5. When the surface of the outdoor third heat exchanger 21b starts frosting with the operation of the heating mode, the outdoor third heat exchanger 21b is replaced by the outdoor second heat exchanger 21a again, and meanwhile, the defrosting process is performed on the outdoor third heat exchanger 21b, and the switching mode of the valves is as follows:
c) the first control valve 71, the third control valve 73, and the sixth control valve 76 are opened, the second control valve 72, the fourth control valve 74, and the fifth control valve 75 are closed, the first throttle device 31 and the third throttle device 33 are opened, and the second throttle device 32 is closed (valve-closed no-flow), as shown in fig. 6.
At this time, the high-temperature and high-pressure refrigerant discharged by the compressor 10 is divided into two paths, wherein one path of refrigerant enters the indoor heat exchanger 41 for heat exchange through an D, E pipe of the four-way valve, is throttled and depressurized through the first throttling device 31, and enters the outdoor second heat exchanger 21a for heat exchange through the first control valve 71; and the other refrigerant enters the outdoor third heat exchanger 21b through the two-way valve 76 to heat the outdoor third heat exchanger 21b, so that the frost layer on the surface of the outdoor third heat exchanger 21b is melted (in this case, the outdoor third heat exchanger 21b is equivalent to a low-temperature condenser). The refrigerant after heat exchange in the outdoor third heat exchanger 21b is throttled and depressurized by the third throttling device 33, then mixed with the refrigerant coming out of the outdoor second heat exchanger 21a, the mixed refrigerant enters the outdoor first heat exchanger 21 for heat exchange, enters the suction port of the compressor 10 through the C, S pipe of the four-way valve after heat exchange is completed, and is compressed to complete the whole cycle.
With the continuous operation of the above cycle, the frost layer on the surface of the outdoor third heat exchanger 21b is gradually melted, when the defrosting mode is continuously operated for 8mins and the pipe wall temperature Twb of the outdoor third heat exchanger 21b is detected to be more than or equal to 10 ℃, the defrosting mode is ended, the two-way valve 76 is closed at this time, the operation mode of the system returns to the working state shown in fig. 3, and the process is repeated. In conclusion, the system fully utilizes the temperature slip characteristic of the non-azeotropic working medium, sacrifices a small part of the area of the outdoor heat exchanger (the outdoor second heat exchanger 21a or the outdoor third heat exchanger 21b), and ensures that the main body of the outdoor heat exchanger (the outdoor first heat exchanger 21) does not frost. The outdoor auxiliary heat exchanger is switched by the valve to realize alternate defrosting and defrosting without stopping, thereby ensuring normal indoor heating. By the control program, during heating operation, the evaporating temperature of the outdoor second heat exchanger 21a or the outdoor third heat exchanger 21b is lower than the dew-point temperature of the outdoor environment, and the evaporating temperature of the outdoor first heat exchanger 21 is higher than the dew-point temperature of the outdoor environment but lower than the dry bulb temperature of the outdoor environment. Therefore, when the outdoor first heat exchanger 21 is operated in a refrigerating mode under the low-temperature working condition, the frost cannot be formed, the frost is only formed on the outdoor second heat exchanger 21a or the outdoor third heat exchanger 21b, and the continuity and the stability of the operation of the system and the comfort of a heating environment are improved.
In some embodiments, in the controlling step, when the air conditioner is operated in the heating mode, and when Tout is greater than or equal to T1 and Tin is less than T3 for a continuous time T1, or when Tout is less than T1 and Tin is less than T2 for a continuous time T1, the first control valve 71 is controlled to be closed, the second control valve 72 is controlled to be opened, and after the time T2, the time T2 is a second preset time;
in the detecting step, the air inlet pressure and the air outlet pressure of the outdoor third heat exchanger 21b can also be detected;
in the judging step, whether a second pressure difference between the air inlet pressure and the air outlet pressure of the outdoor third heat exchanger 21b is greater than or equal to a second preset pressure difference value or not can be judged;
in the control step, when the second pressure difference is greater than or equal to the second preset pressure difference, the first control valve 71 is controlled to be opened, and the second control valve 72 is controlled to be closed; when the second pressure difference is smaller than the second preset pressure difference, the first control valve 71 is kept closed, and the second control valve 72 is kept open.
In some embodiments, the controlling step is further configured to close the fifth control valve 75, open the sixth control valve 76, close the fourth control valve 74, open the third control valve 73, close the second throttling device 32, open the third throttling device 33, and heat the outdoor third heat exchanger 21b to defrost when the second pressure difference is greater than or equal to the second preset pressure difference and the first control valve 71 is controlled to be opened and the second control valve 72 is controlled to be closed.
2.3 heating under severe working conditions
When the outdoor environment is very harsh, the heating load requirement is high, the evaporation temperature is very low, the outdoor first heat exchanger 21 cannot frost due to the temperature slippage of the two auxiliary heat exchangers (the outdoor second heat exchanger 21a and the outdoor third heat exchanger 21b), the surface of the outdoor first heat exchanger 21 also begins to frost, and the heating performance is seriously affected, the defrosting and defrosting treatment needs to be performed on all outdoor heat exchangers. At this time, the four-way valve 51 is switched to the cooling mode, the inside and outside fans are stopped, the first control valve 71 and the second control valve 72 are turned on, and the system cycle is as shown in fig. 1. When the defrosting and defrosting mode operates for 8mins and the wall temperature Tw of the finned tube of the outdoor heat exchanger is more than or equal to 10 ℃, defrosting is finished. The system then operates in heating mode again as shown in fig. 2.
In some embodiments, T3 < T2 < T1; when the air conditioning system further comprises a four-way valve 51:
the control step can also be carried out when the air conditioner operates in a heating mode: and when Tout is less than T4 (which indicates that the outdoor environment is very harsh, the heating load requirement is large, the evaporation temperature is very low, the outdoor first heat exchanger 21 cannot frost due to the temperature slippage of the two auxiliary heat exchangers, the surface of the outdoor first heat exchanger 21 also starts to frost, and the heating performance is seriously influenced; T4 is preferably-15 to-20 ℃ below zero), the first control valve 71 and the second control valve 72 are controlled to be opened, and the four-way valve 51 is controlled to be reversed and switched to the cooling mode to heat and defrost at least one of the outdoor first heat exchanger 21, the outdoor second heat exchanger 21a and the outdoor third heat exchanger 21b, wherein T4 is less than T3.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention. The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.

Claims (14)

1. An air conditioning system characterized by: the method comprises the following steps:
the air conditioning system comprises a compressor (10), an outdoor first heat exchanger (21), an outdoor second heat exchanger (21a), an outdoor third heat exchanger (21b), an indoor heat exchanger (41) and a first throttling device (31), wherein the air conditioning system comprises a first boiling point refrigerant and a second boiling point refrigerant, the boiling point of the first boiling point refrigerant is less than that of the second boiling point refrigerant, one end of the outdoor first heat exchanger (21) can be communicated to a gas discharge end or a gas suction end of the compressor (10), and the other end of the outdoor first heat exchanger can be communicated to one end of the outdoor second heat exchanger (21a) and/or one end of the outdoor third heat exchanger (21 b);
the other end of the outdoor second heat exchanger (21a) is communicated with the other end of the outdoor third heat exchanger (21b) and then can be communicated with one end of the first throttling device (31), the other end of the first throttling device (31) is communicated with one end of the indoor heat exchanger (41), and the other end of the indoor heat exchanger (41) can be selectively communicated to the suction end or the exhaust end of the compressor (10);
the air conditioning system further comprises an eighth pipeline (108) and a ninth pipeline (109), one end of the eighth pipeline (108) is communicated with the exhaust end of the compressor (10), the other end of the eighth pipeline is communicated with the other end of the outdoor second heat exchanger (21a), one end of the ninth pipeline (109) is communicated with the exhaust end of the compressor (10), the other end of the ninth pipeline is communicated with the other end of the outdoor third heat exchanger (21b), a fifth control valve (75) is arranged on the eighth pipeline (108), and a sixth control valve (76) is arranged on the ninth pipeline (109).
2. The air conditioning system of claim 1, wherein:
one end of the outdoor first heat exchanger (21) is selectively communicated to a discharge end or a suction end of the compressor (10) through a first pipeline (101), and the other end is communicated to one end of the outdoor second heat exchanger (21a) and/or one end of the outdoor third heat exchanger (21b) through a second pipeline (102), wherein the outdoor second heat exchanger (21a) is connected with the outdoor third heat exchanger (21b) in parallel.
3. The air conditioning system of claim 2, wherein:
the outdoor second heat exchanger (21a) is located on a third pipeline (103), the outdoor third heat exchanger (21b) is located on a fourth pipeline (104), the third pipeline (103) is connected with the fourth pipeline (104) in parallel, one end of the third pipeline (103) is communicated with one end of the fourth pipeline (104) and then communicated with the second pipeline (102), and the other end of the third pipeline (103) is communicated with the other end of the fourth pipeline (104) and then can be communicated with one end of the indoor heat exchanger (41).
4. The air conditioning system of claim 3, wherein:
a first control valve (71) is arranged on the third pipeline (103) and positioned between the outdoor second heat exchanger (21a) and the first throttling device (31), and a second control valve (72) is arranged on the fourth pipeline (104) and positioned between the outdoor third heat exchanger (21b) and the first throttling device (31);
a third control valve (73) is arranged on the third pipeline (103) and located between the outdoor second heat exchanger (21a) and the outdoor first heat exchanger (21), and a fourth control valve (74) is arranged on the fourth pipeline (104) and located between the outdoor third heat exchanger (21b) and the outdoor first heat exchanger (21).
5. The air conditioning system of claim 4, wherein:
the hydraulic control system is characterized by further comprising a tenth pipeline (110) and an eleventh pipeline (111), wherein the tenth pipeline (110) is arranged on the third control valve (73) in parallel, a second throttling device (32) is further arranged on the tenth pipeline (110), the eleventh pipeline (111) is arranged on the fourth control valve (74) in parallel, and a third throttling device (33) is further arranged on the eleventh pipeline (111).
6. The air conditioning system according to any one of claims 3 to 5, characterized in that:
the air conditioner further comprises a fifth pipeline (105), a sixth pipeline (106) and a seventh pipeline (107), the third pipeline (103) and the fourth pipeline (104) are converged and then communicated to one end of the first throttling device (31) through the fifth pipeline (105), the other end of the first throttling device (31) is communicated to one end of the indoor heat exchanger (41) through the sixth pipeline (106), and the other end of the indoor heat exchanger (41) is communicated to the suction end or the exhaust end of the compressor (10) through the seventh pipeline (107).
7. The air conditioning system of claim 6, wherein:
the four-way valve further comprises a four-way valve (51), the four-way valve comprises an E end (E), an S end (S), a C end (C) and a D end (D), the E end (E) is communicated with the seventh pipeline (107), the S end (S) is communicated with the air suction end of the compressor (10), the C end (C) is communicated with the first pipeline (101), the D end (D) is communicated with the air exhaust end of the compressor (10), and the first communication state of the four-way valve is as follows: the E end (E) is communicated with the S end (S), the C end (C) is communicated with the D end (D), at the moment, the indoor operation is in a refrigerating state, and the second communication state of the four-way valve is as follows: the end E is communicated with the end D, the end S is communicated with the end C, and the indoor operation is in a heating state; the four-way valve (51) can be switched between the first communication state and the second communication state.
8. The air conditioning system according to any one of claims 1 to 7, characterized in that:
the outdoor heat exchanger also comprises a first fan (61), wherein the first fan (61) can drive the outdoor airflow to partially flow through the outdoor first heat exchanger (21), partially flow through the outdoor second heat exchanger (21a) and partially flow through the outdoor third heat exchanger (21 b);
and the air conditioner also comprises a second fan (62), wherein the second fan (62) can drive the air flow in the room to flow through the indoor heat exchanger (41).
9. A control method of an air conditioning system according to any one of claims 1 to 8, characterized in that: the method comprises the following steps:
detecting the operation mode of an air conditioning system, the temperature Tout of an outdoor environment and the inlet temperature Tin of the outdoor second heat exchanger or the outdoor third heat exchanger in a heating mode;
a judging step, namely judging the relation between Tout and a first preset value T1, and judging the relation between Tin and a second preset value T2 and a third preset value T3; wherein T2 > T3;
a control step, when further comprising a first control valve (71) and a second control valve (72):
when the air conditioner is operated in the cooling mode: controlling both the first control valve (71) and the second control valve (72) to open; when the air conditioner operates in the heating mode: when Tout is larger than or equal to T1 and Tin is larger than or equal to T2, the first control valve (71) and the second control valve (72) are controlled to be opened; and when Tout is larger than or equal to T1 and lasts for time Tin < T3 within T1, or when Tout is smaller than T1 and continues for time Tin < T2 within T1, one of the first control valve (71) and the second control valve (72) is controlled to be opened, and the other is controlled to be closed, wherein T1 is a first preset time.
10. The control method according to claim 9, characterized in that:
in the control step, when the air conditioner is operated in the heating mode, and when Tout is larger than or equal to T1 and Tin is less than T3 within continuous T1 time, or when Tout is less than T1 and Tin is less than T2 within continuous T1 time, the first control valve (71) is controlled to be opened, the second control valve (72) is closed, and after T2 time, T2 is second preset time;
the detection step can also detect the air inlet pressure and the air outlet pressure of the outdoor second heat exchanger (21 a);
in the judging step, whether a first pressure difference between the air inlet pressure and the air outlet pressure of the outdoor second heat exchanger (21a) is greater than or equal to a first preset pressure difference value or not can be judged;
the control step can also be carried out when the first pressure difference is larger than or equal to the first preset pressure difference, the first control valve (71) is controlled to be closed, and the second control valve (72) is controlled to be opened; when the first pressure difference is smaller than the first preset pressure difference, the first control valve (71) is kept open, and the second control valve (72) is kept closed.
11. The control method according to claim 10, characterized in that:
when further comprising a third control valve (73), a fourth control valve (74), a fifth control valve (75), a sixth control valve (76), a second throttling means (32) and a third throttling means (33):
and in the control step, when the first pressure difference is larger than or equal to the preset pressure difference, the first control valve (71) is controlled to be closed, and the second control valve (72) is controlled to be opened, the fifth control valve (75) is opened, the sixth control valve (76) is closed, the fourth control valve (74) is opened, the third control valve (73) is closed, the second throttling device (32) is opened, and the third throttling device (33) is closed, so that the outdoor second heat exchanger (21a) is heated and defrosted.
12. The control method according to claim 9, characterized in that:
in the control step, when the air conditioner is operated in the heating mode, when Tout is larger than or equal to T1 and Tin is less than T3 within continuous T1 time or when Tout is less than T1 and Tin is less than T2 within continuous T1 time, the first control valve (71) is controlled to be closed, the second control valve (72) is controlled to be opened, and after T2 time, T2 is second preset time;
the detection step can also detect the air inlet pressure and the air outlet pressure of the outdoor third heat exchanger (21 b);
in the judging step, whether a second pressure difference between the air inlet pressure and the air outlet pressure of the outdoor third heat exchanger (21b) is greater than or equal to a second preset pressure difference value or not can be judged;
the control step can also be carried out, when the second pressure difference is larger than or equal to the second preset pressure difference, the first control valve (71) is controlled to be opened, and the second control valve (72) is controlled to be closed; when the second pressure difference is smaller than the second preset pressure difference, the first control valve (71) is kept closed, and the second control valve (72) is kept open.
13. The control method according to claim 12, characterized in that:
when further comprising a third control valve (73), a fourth control valve (74), a fifth control valve (75), a sixth control valve (76), a second throttling means (32) and a third throttling means (33):
and in the control step, when the second pressure difference is greater than or equal to the second preset pressure difference, the first control valve (71) is controlled to be opened, and the second control valve (72) is controlled to be closed, the fifth control valve (75) is closed, the sixth control valve (76) is opened, the fourth control valve (74) is closed, the third control valve (73) is opened, the second throttling device (32) is closed, and the third throttling device (33) is opened, so that the outdoor third heat exchanger (21b) is heated and defrosted.
14. The control method according to claim 9, characterized in that:
t3 < T2 < T1; when the air conditioning system further comprises a four-way valve (51):
the control step can also be carried out when the air conditioner operates in a heating mode: and when Tout is less than T4, controlling the first control valve (71) and the second control valve (72) to be opened, and controlling the four-way valve (51) to change direction and switch to a cooling mode to heat and defrost at least one of the outdoor first heat exchanger (21), the outdoor second heat exchanger (21a) and the outdoor third heat exchanger (21b), wherein T4 is less than T3.
CN202111263506.8A 2021-10-28 2021-10-28 Air conditioning system and control method thereof Pending CN113864928A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114370692A (en) * 2022-02-28 2022-04-19 海信（广东）空调有限公司 Air conditioner and control method thereof
CN114508786A (en) * 2022-02-17 2022-05-17 珠海格力电器股份有限公司 Air conditioning system, control method and control device of air conditioning system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114508786A (en) * 2022-02-17 2022-05-17 珠海格力电器股份有限公司 Air conditioning system, control method and control device of air conditioning system
CN114370692A (en) * 2022-02-28 2022-04-19 海信（广东）空调有限公司 Air conditioner and control method thereof

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