CN113865005A - Defrosting shunting method, air conditioning system and air conditioning control method - Google Patents

Defrosting shunting method, air conditioning system and air conditioning control method Download PDF

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Publication number
CN113865005A
CN113865005A CN202111267011.2A CN202111267011A CN113865005A CN 113865005 A CN113865005 A CN 113865005A CN 202111267011 A CN202111267011 A CN 202111267011A CN 113865005 A CN113865005 A CN 113865005A
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China
Prior art keywords
heat exchange
air conditioning
bypass
outdoor heat
conditioning system
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CN202111267011.2A
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CN113865005B (en
Inventor
李木湖
陈姣
何振健
冯帅飞
戴志炜
林金煌
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Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
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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
    • F24F1/00—Room units for air-conditioning, e.g. separate or self-contained units or units receiving primary air from a central station
    • F24F1/0003—Room units for air-conditioning, e.g. separate or self-contained units or units receiving primary air from a central station characterised by a split arrangement, wherein parts of the air-conditioning system, e.g. evaporator and condenser, are in separately located 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
    • F24F11/62—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
    • F24F11/72—Control systems characterised by their outputs; Constructional details thereof for controlling the supply of treated air, e.g. its pressure
    • F24F11/74—Control systems characterised by their outputs; Constructional details thereof for controlling the supply of treated air, e.g. its pressure for controlling air flow rate or air velocity
    • F24F11/77—Control systems characterised by their outputs; Constructional details thereof for controlling the supply of treated air, e.g. its pressure for controlling air flow rate or air velocity by controlling the speed of ventilators
    • 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
    • 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
    • F25B41/30—Expansion means; Dispositions thereof
    • F25B41/31—Expansion 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
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/40—Fluid line arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
    • F25D21/00—Defrosting; Preventing frosting; Removing condensed or defrost water
    • F25D21/06—Removing frost
    • 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)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Signal Processing (AREA)
  • Thermal Sciences (AREA)
  • Fuzzy Systems (AREA)
  • Mathematical Physics (AREA)
  • Fluid Mechanics (AREA)
  • Air Conditioning Control Device (AREA)

Abstract

The invention provides a defrosting shunting method, an air conditioning system and an air conditioning control method, wherein the defrosting shunting method is used for shunting refrigerants of an outdoor heat exchanger in the air conditioning system, and comprises the following steps: determining a heat exchange difference value delta k between the maximum heat exchange coefficient and the minimum heat exchange coefficient of an outdoor heat exchange tube of the outdoor heat exchanger and the tube length L of the outdoor heat exchange tube; judging the frost formation amount or the difference of the heat exchange amount along the pipeline flowing direction of the outdoor heat exchange pipe according to the heat exchange difference value delta k and the pipe length L so as to determine the number n of bypass branches communicated with the outdoor heat exchange pipe; one end of the bypass branch is communicated with an outlet of the air conditioning system, and the other end of the bypass branch is communicated with the middle part of the outdoor heat exchange tube; n is an integer greater than or equal to 0, so that the problem of low defrosting efficiency of the air conditioner in the prior art is solved.

Description

Defrosting shunting method, air conditioning system and air conditioning control method
Technical Field
The invention relates to an air conditioning system, in particular to a defrosting shunting method, an air conditioning system and an air conditioning control method.
Background
The frosting problem of the air-cooled heat exchanger is a key problem which restricts the popularization and application of the air source heat pump air conditioner in low-temperature and high-humidity areas in winter. When a user uses the air conditioner to heat in winter, the outdoor heat exchanger absorbs heat from outdoor air and supplies the heat to the indoor, and when the outdoor environment temperature is lower than 7 ℃ and the relative humidity is more than 50%, the heat exchanger frosts. As the frost layer becomes thicker, the thermal resistance of the outdoor heat exchanger increases, the heat exchange efficiency decreases, the heating capacity of the air conditioner significantly decreases, and the operation energy efficiency decreases, so that defrosting needs to be performed at regular time to improve the energy efficiency of the air conditioner. Along with the increasing demand of heat pump air-conditioning heating, the problems of heat efficiency and comfort caused by frequent defrosting of the air-conditioning in low-temperature and high-humidity areas become more and more prominent, and a set of efficient and comfortable defrosting technology is urgently needed in the industry.
The defrosting technology of the heat exchanger can be roughly divided into thermal defrosting and non-thermal defrosting, wherein the thermal defrosting can be divided into in-pipe heat exchange defrosting and out-pipe heat exchange defrosting according to the heat exchange mode. In the defrosting process, part of heat supply of the heat source is dissipated to low-temperature outdoor air, and the part of heat does not directly act on a frost layer, so that the heat is defined as invalid heat consumption of the system, and the thermal defrosting air-conditioning system has certain defrosting efficiency (or system defrosting heat utilization rate).
The heat defrosting mode of the existing heat exchanger is various, and the heat defrosting mode can be divided into near air side heat exchange defrosting and near tube side heat exchange defrosting according to the heat absorption and melting direction of a frost layer. The external heat exchange defrosting (such as infrared defrosting or electric heating defrosting) is used as an auxiliary device of an air conditioning system, can provide enough heat for quick defrosting of the near air side of a frost layer, but the heat dissipated to outdoor air by the system is also large, the utilization rate of defrosting heat is low, and meanwhile, the safety and reliability problems exist.
For the in-tube heat exchange defrosting mode (such as conventional reverse cycle defrosting, hot gas bypass defrosting, heat storage defrosting and the like), defrosting heat directly acts on the near-tube side of a frost layer and is transmitted to the air side, theoretically, the heat dissipated to the air side is relatively small, defrosting efficiency is relatively high, but the defrosting heat is limited by the reliability of an air conditioning system, the defrosting heat of the system is limited, generally, the defrosting heat is only 1/4-1/3 of normal heating or even less, the defrosting heat is gradually attenuated along the flowing direction of a refrigerant in a tube, the defrosting of each tube section is asynchronous, defrosting time in the practical application process is long, part of the tube sections are dry-burned in the defrosting process, the heat is dissipated to outdoor air, and defrosting efficiency is reduced.
For the thermal defrosting mode of the heat exchanger, besides the reason that the defrosting efficiency is low due to the heat supply mode of the heat source in the defrosting process, the phenomenon of uneven frosting in the frosting process of the outdoor heat exchanger is also one of important reasons for influencing the defrosting efficiency. In the normal heating process, along the flowing direction of the refrigerant in the pipe, the heat absorption capacity of the outdoor heat exchanger from outdoor air is generally gradually attenuated, the frosting amount of the heat exchanger is also gradually reduced, and meanwhile, the frosting amount is generally uneven under the influence of the air flow rate and the temperature/humidity difference outside the pipe of different pipe sections. Under the double influences of uneven frosting amount distribution and uneven defrosting heat distribution of the air source heat pump air conditioner, the defrosting efficiency is greatly reduced, and the system energy loss caused by the defrosting of the air conditioner is huge.
It can be seen that the prior art defrosting method has at least the following problems:
the defrosting heat is increased and the defrosting speed is increased by various technical means, but the utilization rate of the defrosting heat is still low, and the expected improvement effect is difficult to achieve. If the conventional reverse cycle defrosting is adopted, the heating is switched into the cooling operation during the defrosting, the energy loss is large in the switching process, the problem that the frosting and defrosting of the heat exchanger are not synchronous is not solved, the defrosting heat utilization rate is low, and meanwhile, the indoor heat is absorbed and used for defrosting of the outdoor heat exchanger, so that the indoor temperature drop is greatly reduced, and the thermal comfort of a human body is reduced.
The structure and the control method for improving the defrosting rate by performing bypass defrosting on a heat exchanger in the prior art solve the problem of low defrosting efficiency caused by uneven defrosting amount, but because the parameters of the heat exchanger change in real time during defrosting, and the positions of bypass shunts are fixed, on the premise that the corresponding relation between the resistance flow of a pipe network and the real-time change of the defrosting amount of each pipe section is not established, the synchronous defrosting effect of each pipe section of the heat exchanger is relatively poor, and the expected defrosting efficiency improving effect is difficult to achieve.
Disclosure of Invention
The invention mainly aims to provide a defrosting shunting method, an air conditioning system and an air conditioning control method, so as to solve the problem of low defrosting efficiency of an air conditioner in the prior art.
In order to achieve the above object, according to an aspect of the present invention, there is provided a defrosting split method for splitting a refrigerant of an outdoor heat exchanger in an air conditioning system, the defrosting split method including: determining a heat exchange difference value delta k between the maximum heat exchange coefficient and the minimum heat exchange coefficient of an outdoor heat exchange tube of the outdoor heat exchanger and the tube length L of the outdoor heat exchange tube; judging the frost formation amount or the difference of the heat exchange amount along the pipeline flowing direction of the outdoor heat exchange pipe according to the heat exchange difference value delta k and the pipe length L so as to determine the number n of bypass branches communicated with the outdoor heat exchange pipe; one end of the bypass branch is communicated with an outlet of the air conditioning system, and the other end of the bypass branch is communicated with the middle part of the outdoor heat exchange tube; n is an integer greater than or equal to 0.
Further, the defrosting diversion method further comprises the following steps: and determining the heat exchange coefficient k of each position of each outdoor heat exchange tube of the outdoor heat exchanger according to the parameters of the outdoor heat exchanger so as to determine the maximum heat exchange coefficient and the minimum heat exchange coefficient of the outdoor heat exchange tubes.
Further, after determining the heat exchange coefficient k of each position of each outdoor heat exchange tube, the defrosting shunting method further comprises the following steps: drawing a heat exchange coefficient k-x curve of the corresponding outdoor heat exchange tube; determining the maximum heat exchange coefficient and the minimum heat exchange coefficient of the outdoor heat exchange tube according to the heat exchange coefficient k-x curve; in the heat exchange coefficient k-x curve, the origin of coordinates is a refrigerant inlet point when the air conditioning system is in heating operation, the abscissa x represents the tube length of the outdoor heat exchange tube, the direction of the abscissa x is the flowing direction of the refrigerant in the outdoor heat exchange tube, and the ordinate k represents the heat exchange coefficient k.
Further, after determining the number n of bypass branches, the defrost diversion method further includes: determining the ratio of frosting amount of a plurality of heat exchange tube sections of the outdoor heat exchange tube after the outdoor heat exchange tube is divided by the n bypass branches according to the flow resistance of the n bypass branches; and determining the position of a bypass node of the outdoor heat exchange tube, which is used for communicating with the bypass branch, according to the heat exchange quantity of each position of the outdoor heat exchange tube along the flowing direction of the refrigerant and the ratio of the frosting quantities of the plurality of heat exchange tube sections.
Further, the defrosting diversion method further comprises the following steps: when the air conditioning system is in a heating mode, calculating the heat exchange quantity of each position of the outdoor heat exchange tube along the flowing direction of the refrigerant; and according to the heat exchange quantity of each position of the outdoor heat exchange tube along the flowing direction of the refrigerant, obtaining the circulation resistance of the n bypass branches.
Further, after obtaining the heat exchange amount of each position of the outdoor heat exchange tube along the refrigerant flowing direction, the defrosting and shunting method further comprises the following steps: and acquiring an M-x distribution curve of the frosting amount M along the tube length direction of the outdoor heat exchange tube, and determining the position of a bypass node of the outdoor heat exchange tube according to the M-x distribution curve and the ratio of the frosting amounts of a plurality of heat exchange tube sections.
Further, the method for determining the number n of the bypass branches communicated with the outdoor heat exchange pipe comprises the following steps: when the delta k is smaller than a first preset heat exchange coefficient k1Then, the actual length L and the first preset length L of the outdoor heat exchange tube are judged1The magnitude relationship between them; when the actual pipe length L is less than or equal to the first preset pipeLong L1When n is 0, n is taken.
Further, the method for determining the number n of the bypass branches communicated with the outdoor heat exchange pipe comprises the following steps: when the delta k is more than or equal to a first preset heat exchange coefficient k1And is less than or equal to a second preset heat exchange coefficient k2Then, the actual length L and the second preset length L of the outdoor heat exchange tube are judged2The magnitude relationship between them; second predetermined tube length L2Is less than the first preset pipe length L1(ii) a When the actual pipe length L is less than or equal to the second preset pipe length L2When n is 0; otherwise, according to the actual tube length L and the first preset heat exchange coefficient k1Obtaining the minimum number of bypass branches communicated with the outdoor heat exchange tube, and obtaining the minimum number of bypass branches communicated with the outdoor heat exchange tube according to the actual tube length L and a second preset heat exchange coefficient k2And obtaining the maximum value of the bypass branches communicated with the outdoor heat exchange tube, and determining the number n of the bypass branches according to the delta k.
Further, the method for determining the number n of the bypass branches communicated with the outdoor heat exchange pipe comprises the following steps: when delta k is larger than a second preset heat exchange coefficient k2The heat exchange pipe section is divided into a first heat exchange pipe section and a second heat exchange pipe section, and the maximum heat exchange coefficient difference value of the first heat exchange pipe section and the second heat exchange pipe section is smaller than k2(ii) a And judging the number n of bypass branches communicated with the shunting of the first heat exchange pipe section and the second heat exchange pipe section respectively according to the maximum heat exchange coefficient difference value of the first heat exchange pipe section and the second heat exchange pipe section and the length of the pipe sections.
According to a second aspect of the present invention, there is provided an air conditioning system including a compressor, an outdoor heat exchanger, and an indoor heat exchanger, which are sequentially connected by piping to form a refrigerant circulation line, the outdoor heat exchanger including at least one outdoor heat exchange pipe, the outdoor heat exchange pipe including at least two heat exchange pipe sections communicated with each other, the air conditioning system comprising: one end of each bypass branch is communicated with an outlet of the compressor, and the other end of each bypass branch is connected with a bypass node between two corresponding adjacent heat exchange tube sections; and each heat exchange pipe section is provided with one temperature sensing part so as to control the defrosting state of the air conditioning system according to the detection results of the temperature sensing parts.
Furthermore, the number of the heat exchange tube sections is more than two, and each outdoor heat exchange tube is provided with a plurality of bypass nodes formed by two adjacent heat exchange tube sections; the bypass branches are multiple and are connected with corresponding bypass nodes in a one-to-one correspondence mode.
Further, the air conditioning system further includes: the first expansion valve is arranged on a pipe section of the refrigerant circulating pipeline between the indoor heat exchanger and the outdoor heat exchanger; and/or a second expansion valve disposed on the bypass branch.
Further, the air conditioning system further includes: the bypass control valve is arranged on the bypass branch to control the on-off of the bypass branch; and/or a refrigerant control valve arranged on the refrigerant circulating pipeline to control the on-off of the refrigerant circulating pipeline.
Furthermore, the outdoor heat exchange tubes are multiple, the bypass branches are multiple, and each outdoor heat exchange tube is communicated with at least one bypass branch.
According to a third aspect of the present invention, there is provided an air conditioning control method, which is applied to the air conditioning system, wherein the air conditioning system includes a defrosting mode, and when the air conditioning system is in the defrosting mode, the air conditioning control method includes: detecting the pipe temperature of each heat exchange pipe section of an outdoor heat exchanger of an air conditioning system in real time; and adjusting the on-off state of the bypass branch according to the pipe temperature of each heat exchange pipe section so as to adjust the defrosting state of the defrosting mode.
Further, the method for controlling the on-off state of the bypass branch comprises the following steps: when the pipe temperature of at least one heat exchange pipe section of the air-conditioning system is higher than a first preset temperature, controlling all bypass branches of the air-conditioning system to be in a disconnected state so as to enable the air-conditioning system to exit a defrosting mode; otherwise, the bypass branch is controlled to maintain the conducting state, so that the air conditioning system is continuously in the defrosting mode.
Further, the air conditioner control method further includes: acquiring the temperature rise rates of at least two heat exchange pipe sections of the air conditioning system; when the pipe temperatures of all the heat exchange pipe sections of the air conditioning system are less than or equal to a first preset temperature, the operation state of the defrosting mode is adjusted according to the temperature rise rates of at least two heat exchange pipe sections.
Further, the at least two heat exchange tube sections include a first heat exchange tube section and a second heat exchange tube section which are sequentially and adjacently arranged along the flowing direction of the refrigerant, and the adjusting of the operation state of the defrosting mode includes: the temperature rise rate V of the second heat exchange tube sectionTdTemperature rise rate V from the first heat exchange tube sectionTbCarrying out ratio operation to obtain the temperature rise rate ratio alpha-VTd/VTb(ii) a And adjusting the running state of the defrosting mode according to the temperature rise rate ratio alpha.
Further, adjusting the operating state of the defrost mode includes: when the temperature rise rate ratio alpha is smaller than beta-epsilon, increasing the unit refrigerant circulation of a bypass branch communicated with a bypass node between the first heat exchange pipe section and the second heat exchange pipe section, or reducing the unit refrigerant circulation of the first heat exchange pipe section, or increasing the rotating speed of an inner fan of an air-conditioning indoor unit of the air-conditioning system; when the value range of the temperature rise rate ratio alpha is that beta-epsilon is not less than alpha and not more than beta + epsilon, controlling the air conditioning system to maintain the current defrosting operation state, and continuously comparing the pipe temperature of each heat exchange pipe section with the first preset temperature; and when the temperature rise rate ratio alpha is larger than beta + epsilon, reducing the unit refrigerant circulation of a bypass branch communicated with a bypass node between the first heat exchange pipe section and the second heat exchange pipe section, or increasing the unit refrigerant circulation of the first heat exchange pipe section, or reducing the rotating speed of an inner fan of an air-conditioning indoor unit of the air-conditioning system.
Further, the method of adjusting the unit refrigerant flow rate of the bypass branch path includes: increasing or decreasing the opening of a bypass control valve located on the bypass branch; and/or the method of adjusting the unit refrigerant flow capacity of the first heat exchange tube section comprises: the opening degree of a refrigerant control valve provided on a refrigerant circulation line is increased or decreased.
Further, after the unit refrigerant flow rate of the bypass branch, or the unit refrigerant flow rate of the second heat exchange pipe section, or the rotation speed of the internal fan is adjusted, the operation frequency of the compressor of the air conditioning system is controlled according to the adjusted opening sizes of the bypass control valve and the refrigerant control valve, and the phase current of the air conditioning system.
Further, after the air conditioning system starts the defrosting mode, the air conditioning control method includes: and opening the bypass control valve to enable the air conditioning system to enter the defrosting mode to operate.
Further, before the air conditioning system enters the defrosting mode to operate, the air conditioning control method further comprises the following steps: detecting and recording outdoor ambient temperature TwIndoor ambient temperature TnOutdoor tube temperature of each heat exchange tube section of outdoor heat exchanger of air conditioning system, indoor tube temperature T of indoor heat exchange tube of indoor heat exchanger of air conditioning systemsThe rotating speed of an outer fan of the air conditioning system and the rotating speed of an inner fan of the air conditioning system.
By applying the technical scheme of the invention, the defrosting shunting method provided by the invention comprises the following steps: determining a heat exchange difference value delta k between the maximum heat exchange coefficient and the minimum heat exchange coefficient of an outdoor heat exchange tube of the outdoor heat exchanger and the tube length L of the outdoor heat exchange tube; judging the frost formation amount or the difference of the heat exchange amount along the pipeline flowing direction of the outdoor heat exchange pipe according to the heat exchange difference value delta k and the pipe length L so as to determine the number n of bypass branches communicated with the outdoor heat exchange pipe; one end of the bypass branch is communicated with an outlet of the air conditioning system, and the other end of the bypass branch is communicated with the middle part of the outdoor heat exchange tube; n is an integer greater than or equal to 0. Therefore, the defrosting and shunting method determines the number of the bypass branches to shunt the refrigerant of the outdoor heat exchanger in the air conditioning system, so that all heat exchange pipe sections of the indoor heat exchange pipe of the outdoor heat exchanger can be defrosted synchronously, and the problems of poor synchronous defrosting effect and low defrosting efficiency in the prior art are solved.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 illustrates a schematic diagram of an efficient defrost air conditioning system according to an embodiment of the air conditioning system of the present invention;
fig. 2 is a schematic view illustrating a defrosting heat distribution structure and distribution position thereof according to an embodiment of an air conditioning system of the present invention;
FIG. 3 illustrates a real-time optimized distribution control of heat for an efficient defrost system with only one bypass branch according to an embodiment of the air conditioning control method of the present invention; and
fig. 4 shows a method of designing the number of bypass branch lines according to an embodiment of the defrosting division method of the present invention.
Wherein the figures include the following reference numerals:
1. a compressor; 2. an outdoor heat exchanger; 20. an outdoor heat exchange pipe; 200. a heat exchange tube section; 201. a first heat exchange tube section; 202. a second heat exchange tube section; 210. a bypass node; 3. an indoor heat exchanger; 4. a temperature sensing member; 100. a refrigerant circulation line; 101. a bypass branch; 5. a first expansion valve; 6. a second expansion valve; 7. a bypass control valve; 8. a refrigerant control valve.
Detailed Description
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
Referring to fig. 4, the present invention provides a defrosting and shunting method for shunting a refrigerant of an outdoor heat exchanger 2 in an air conditioning system, the defrosting and shunting method includes: determining a heat exchange difference value delta k between the maximum heat exchange coefficient and the minimum heat exchange coefficient of an outdoor heat exchange tube 20 of the outdoor heat exchanger 2 and the tube length L of the outdoor heat exchange tube 20; judging the frost formation amount or the difference of the heat exchange amount along the pipeline flowing direction of the outdoor heat exchange pipe 20 according to the heat exchange difference value delta k and the pipe length L so as to determine the number n of the bypass branches 101 communicated with the outdoor heat exchange pipe 20; one end of the bypass branch 101 is communicated with an outlet of the air conditioning system, and the other end of the bypass branch 101 is communicated with the middle part of the outdoor heat exchange tube 20; n is an integer greater than or equal to 0.
The defrosting shunting method provided by the invention comprises the following steps: determining a heat exchange difference value delta k between the maximum heat exchange coefficient and the minimum heat exchange coefficient of an outdoor heat exchange tube 20 of the outdoor heat exchanger 2 and the tube length L of the outdoor heat exchange tube 20; judging the frost formation amount or the difference of the heat exchange amount along the pipeline flowing direction of the outdoor heat exchange pipe 20 according to the heat exchange difference value delta k and the pipe length L so as to determine the number n of the bypass branches 101 communicated with the outdoor heat exchange pipe 20; one end of the bypass branch 101 is communicated with an outlet of the air conditioning system, and the other end of the bypass branch 101 is communicated with the middle part of the outdoor heat exchange tube 20; n is an integer greater than or equal to 0. In this way, the number of the bypass branches 101 is determined by the defrosting and shunting method of the present invention to shunt the refrigerant of the outdoor heat exchanger 2 in the air conditioning system, so that each heat exchange tube segment 200 of the outdoor heat exchange tube 20 of the outdoor heat exchanger 2 can be defrosted synchronously, thereby solving the problems of poor synchronous defrosting effect and low defrosting efficiency in the prior art.
In the embodiment of the present invention, the heat exchange coefficient k of each position of each outdoor heat exchange tube 20 of the outdoor heat exchanger 2 is determined according to the parameter of the outdoor heat exchanger 2, so as to determine the maximum heat exchange coefficient and the minimum heat exchange coefficient of the outdoor heat exchange tube 20.
Specifically, according to the pipe diameter D, the pipe length L, the pipe fin ratio and the surface wind speed v of the single outdoor heat exchange pipe 20 of the outdoor heat exchanger 2xThe distribution and other parameters of the single tube are used for confirming the heat exchange coefficient k of the single tube, and a k-x curve is drawn.
Because the outer side of the outdoor heat exchange tube 20 exchanges heat with air and the inner side of the outdoor heat exchange tube 20 exchanges heat with a refrigerant, the heat exchange processes are both phase change convection heat exchange processes, and the specific numerical value of the heat exchange coefficient k can obtain a theoretical solution by utilizing the nussel theory, but is difficult to apply in practical engineering. Therefore, the inner side of the tube can be subjected to linear analysis to obtain the convective heat transfer coefficient h of the inner surfaceiApproximate solution, the convection heat transfer coefficient h of the outer surface is obtained by the outer side of the tube according to the difference of the surface wind speed distribution of the heat exchangero。
In the case of the example of the present invention,
for the same heat exchanger, the convection heat transfer coefficient h of the inner surfaceiThe difference of (a) is related to the dryness fraction χ, i.e. h, of the main refrigeranti＝f(χ)；
For the same heat exchanger, the convective heat transfer coefficient h of the outer surfaceoMainly related to the wind speed v on the outer surface of the heat exchangerxIn connection with, i.e. withho＝f(vx)；
The calculation expression of the single-tube heat exchange coefficient k is as follows:
Figure BDA0003327109430000061
in the formula (d)oIs the outer diameter of the heat exchange tube diThe inner diameter of the heat exchange tube is shown, and the lambda is the heat conductivity coefficient of the copper tube. In the actual design process, the difference of the heat exchange amount is indirectly judged by detecting the tube temperature at different positions of the tube section.
In the specific implementation process of the embodiment of the present invention, the design rule of the number of the bypass branches 101 aims to ensure that the heat exchange of each heat exchange pipe section 200 of the outdoor heat exchanger 2 is sufficient and fast, and the maximum allowable number of the bypass branches of the air conditioning system is assumed to be nmaxThe minimum number of bypass branches is nminThen, the following conditions are present:
1) if n is greater than nmaxThat is, when the number of the bypass branches 101 of the air conditioning system is too large, and the total flow rate of the refrigerant of the air conditioning system is limited, the flow rate of each bypass branch 101 is small, the on-way pressure loss and the local pressure loss of the system are increased, and the heat loss of the defrosting bypass structure is too large, which is not favorable for improving the defrosting efficiency. In addition, insufficient defrosting heat exchange of a part of the bypass branches 101 occurs, and excessive heat at the outlets of the bypass branches 101 has an excessive influence on the heat of other bypass branches 101, so that the defrosting heat is difficult to control and distribute, and the defrosting is asynchronous.
2) If n is less than nminThat is, the number of the bypass branches 101 of the air conditioning system is too small, the adjustment range for adjusting the flow of each bypass branch 101 through the valve is limited, and when the flow of each bypass branch 101 is respectively adjusted to the extreme value, at least one bypass branch 101 is seriously out of synchronization with the other bypass branches 101 in defrosting (the defrosting time difference Δ t is more than t)1) And the defrosting split-flow structure has poor defrosting efficiency improving effect.
Therefore, the number n of bypass branches 101 should be controlled to be [ n ]min，nmax]In which n ismin、nmaxThe heat exchange coefficient k value curves of different positions of each heat exchange pipe section 200 of the outdoor heat exchanger 2 are combined with the maximum/minimum k value differenceDetermining the different pipe diameters D and the pipe lengths L.
In an embodiment of the present invention, after determining the heat exchange coefficient k of each position of each outdoor heat exchange pipe 20, the air conditioning control method further includes: drawing a heat exchange coefficient k-x curve of the corresponding outdoor heat exchange tube 20; determining the maximum heat exchange coefficient and the minimum heat exchange coefficient of the outdoor heat exchange tube 20 according to the heat exchange coefficient k-x curve; in the heat exchange coefficient k-x curve, the origin of coordinates is a refrigerant inlet point when the air conditioning system is in heating operation, the abscissa x represents the tube length of the outdoor heat exchange tube 20, the direction of the abscissa x is the flowing direction of the refrigerant in the outdoor heat exchange tube 20, and the ordinate k represents the heat exchange coefficient k.
Specifically, the origin of coordinates is the point of entry of the refrigerant before it flows into the outdoor heat exchanger 2.
In the specific implementation process of the embodiment of the invention, a k-x curve is calculated according to a heat exchange coefficient curve, and the maximum heat exchange coefficient difference value delta k-k is obtainedmax-kminAnd the corresponding position and the distance of the tube are measured, and the tube length L and the first preset heat exchange coefficient k are judged by1A second predetermined heat transfer coefficient k2Value, first preset tube length L1The value, and thus the number of bypass branches 101.
In an embodiment of the present invention, the method for determining the number n of the bypass branches 101 communicating with the outdoor heat exchange pipe 20 comprises: when the delta k is smaller than a first preset heat exchange coefficient k1Then, the actual tube length L and the first predetermined tube length L of the outdoor heat exchange tube 20 are determined1The magnitude relationship between them; when the actual pipe length L is less than or equal to the first preset pipe length L1When n is 0, n is taken.
Specifically, when the delta k is smaller than a first preset heat exchange coefficient k1In the meantime, the heat exchange coefficient heat exchange difference between the positions of the heat exchange pipe sections 200 of the outdoor heat exchanger 2 is not great, and therefore, the actual pipe length L and the first preset pipe length L are continuously judged at this time1The relationship (2) of (c). When the actual pipe length L is less than or equal to the first preset pipe length L1When the defrosting is carried out, the length of the single outdoor heat exchange tube 20 of the outdoor heat exchanger 2 is short, the difference between the synchronicity of the defrosting by adopting bypass flow dividing and the original system flow is small, the defrosting of each section is synchronous, and therefore the defrosting is carried outn is 0; when the actual pipe length L is larger than the first preset pipe length L1In the process, the length of each outdoor heat exchange tube 20 of the outdoor heat exchanger 2 is long, the difference of frost formation amount of each section along the length direction of the tube is large, and the number n of the bypass branch circuits is directly determined according to the actual length L of the tube.
In an embodiment of the present invention, the method for determining the number n of the bypass branches 101 communicating with the outdoor heat exchange pipe 20 comprises: when the delta k is more than or equal to a first preset heat exchange coefficient k1And is less than or equal to a second preset heat exchange coefficient k2Then, the actual tube length L and the second predetermined tube length L of the outdoor heat exchange tube 20 are determined2The magnitude relationship between them; second predetermined tube length L2Is less than the first preset pipe length L1(ii) a When the actual pipe length L is less than or equal to the second preset pipe length L2During defrosting, the sections are synchronous, bypass flow division is not carried out, and n is 0; otherwise, according to the actual tube length L and the first preset heat exchange coefficient k1Obtaining the minimum number of the bypass branch 101 communicated with the outdoor heat exchange pipe 20 and according to the actual pipe length L and the second preset heat exchange coefficient k2The maximum value of the bypass branch 101 communicated with the outdoor heat exchange pipe 20 is obtained, and the number n of the bypass branch 101 is determined according to delta k.
Specifically, when the delta k is more than or equal to a first preset heat exchange coefficient k1And is less than or equal to a second preset heat exchange coefficient k2When the difference of heat exchange coefficients of all positions of the heat exchanger is large, the difference of frost formation amount is large, and the pipe length L and the preset pipe length L are continuously judged2Of (b), wherein L2Less than L1The more the outdoor heat exchange tube 20 is divided into the heat exchange tube segments 200, the larger the difference of the heat exchange coefficients k, and the more bypass flow division is required.
Specifically, the method for determining the number n of the bypass branches 101 communicated with the outdoor heat exchange pipe 20 comprises the following steps: when delta k is larger than a second preset heat exchange coefficient k2In the meantime, the heat exchange tube section 200 is divided into a first heat exchange tube section 201 and a second heat exchange tube section 202, and the maximum heat exchange coefficient difference values of the first heat exchange tube section 201 and the second heat exchange tube section 202 are smaller than k2(ii) a According to the maximum heat exchange coefficient difference and the length of the first heat exchange pipe section 201 and the second heat exchange pipe section 202The number n of bypass legs 101 communicating with the diverging streams of the first and second heat exchange tube sections 201 and 202, respectively, is determined.
In the embodiment of the invention, when Δ k is too large, it indicates that the capacity of the outdoor heat exchanger 2 is seriously uneven, and the outdoor heat exchanger 2 should be optimally adjusted.
Further, after determining the number n of the bypass branch 101, the defrosting diversion method further includes: determining the ratio of frosting amount of the plurality of heat exchange tube sections 200 after the outdoor heat exchange tube 20 is shunted according to the flow resistance of the n bypass branches 101; the bypass node position of the outdoor heat exchange tube 20 is determined according to the magnitude of the heat exchange amount at each position of the outdoor heat exchange tube 20 in the refrigerant flowing direction and the ratio of the frost formation amounts of the plurality of heat exchange tube sections 200.
When the air conditioning system is in a heating mode, calculating the heat exchange quantity of each position of the outdoor heat exchange pipe 20 along the flowing direction of the refrigerant; the flow resistances of the n bypass branches 101 are obtained according to the heat exchange amount of each position of the outdoor heat exchange tube 20 along the refrigerant flowing direction.
Specifically, after obtaining the heat exchange amount of each position of the outdoor heat exchange tube 20 along the refrigerant flowing direction, the defrosting shunting method further includes: an M-x distribution curve of the frost formation amount M along the tube length direction of the outdoor heat exchange tube 20 is obtained to determine the position of the bypass node 210 of the outdoor heat exchange tube 20 according to the M-x distribution curve and the ratio of the frost formation amounts of the plurality of heat exchange tube sections 200.
Specifically, taking a bypass (n ═ 1) as an example, as shown in fig. 1 and 2, a defrosting heat supply branching structure and a branching position thereof are illustrated. The bd section is a plan view of a single heat exchange tube section 200 of the outdoor heat exchanger 2. The abcd section in the figure represents the hot air defrosting process of the original system of the air conditioner: the method comprises the following steps that exhaust air of a compressor 1 of the air conditioner passes through an indoor heat exchanger 3, a fan of the indoor heat exchanger 3 is closed, and then enters an outdoor heat exchanger 2 from a refrigerant inlet of the outdoor heat exchanger 2 through a first expansion valve 5 to be defrosted, wherein the opening degree of the first expansion valve 5 is opened to the maximum; or the hot gas defrosting process is that the compressor 1 exhausts the gas and then directly enters the outdoor heat exchanger 2 without passing through the indoor heat exchanger 3.
The section aec shows the defrosting bypass branch 101, which includes a set of valves, such as a bypass control valve 7 and a second expansion valve 6, for controlling the opening and closing of the bypass branch 101 and the flow rate adjustment, and the discharge air of the compressor 1 passes through the bypass branch 101 to enter the point c in the outdoor heat exchanger 2, and is mixed with the main flow path of the refrigerant circulation line 100 and then enters the cd section for defrosting. The heat exchange tube section 200 of the outdoor heat exchanger 2 is divided into n +1 sections according to the number of nodes of the bypass branch 101, and each heat exchange tube section 200 is provided with a tube temperature sensing bulb representing the average temperature of the section, such as two temperature sensing parts 4 shown in fig. 1.
Preferably, the bypass control valve 7 is a two-way valve.
The node position of the bypass branch 101 is determined according to the resistance flow of the air conditioning system pipe network and the frosting amount of the outdoor heat exchanger 2, and the specific determination method is shown in fig. 4:
firstly, calculating the length heat exchange quantity of each unit outdoor heat exchange tube 20 along the flowing direction of a refrigerant when the air conditioner normally heats according to a heat exchange coefficient k-x curve;
estimating an M-x distribution curve of the frosting amount M along the length direction of the pipe according to the difference of the heat exchange amount;
thirdly, calculating the on-way resistance h of each parallel branch (such as abc section and aec section in figure 1) according to the parameters of the valve and the pipelinefLocal resistance hjSize, listing the maximum resistance h of each bypass branch 101maxWith a minimum resistance hmin；
In particular, the on-way resistance hfThe method is calculated according to the state of a refrigerant and the pipe diameter of a heat exchange pipe, and is embodied as refrigerant pressure loss; local resistance hjThe number of valves, the valve structure, and the valve opening degree of the bypass branch 101 are different.
Wherein, the on-way resistance h is the same when the refrigerant state is the samefThe minimum opening and the maximum opening of the valve correspond to the maximum resistance hmaxWith a minimum resistance hmin。
In an embodiment of the present invention, the in-path resistance h of each parallel branch (e.g., abc segment, aec segment of FIG. 1)fLocal resistance hjThe method comprises the following specific steps:
the resistance of each heat exchange tube segment 200 through which the bypass branch 101 flows includes an on-way resistance hfAnd local resistance hjThe values are respectively related to a dimensionless on-way resistance coefficient lambda and a dimensionless local resistance coefficient xi. For a segment of a pipe that is in turbulent flow, λ can be calculated by:
Figure BDA0003327109430000091
the on-way resistance calculation formula of the pipe section can be expressed as:
Figure BDA0003327109430000092
wherein σ is the equivalent absolute roughness of the tube wall; d is the equivalent inner diameter of the pipe section; sigma/d is the relative roughness of the pipe section; redIs the Reynolds number of the refrigerant fluid; l is the total length of the heat exchange tube section 200 through which the bypass branch 101 flows; v is the fluid characteristic flow velocity, and m/s and rho are the density of the refrigerant in the heat exchange tube section.
The dimensionless local drag coefficient ξ may be retrieved from a related manual or supplied by the manufacturer. The pressure loss of the equipment can be greatly changed due to different models, and the provided estimated value can be used for replacing the pressure loss in the calculation. The local resistance of the valve can be expressed as:
Figure BDA0003327109430000093
fourthly, according to the resistance of each bypass branch 101, the refrigerant flow ratio m of each bypass branch 101 is calculated0：m1(m0Represents the original system flow path, m1Represents the 1 st bypass branch);
the resistance pressure drop of each bypass branch 101 of the pipe network conforms to kirchhoff's law, namely the flow losses in each bypass branch 101 of the parallel pipelines are the same, namely the pressure drops are the same, and the flow of each bypass branch 101 is determined by the resistance coefficient of the branch. For example, a system with 2 branches has
Figure BDA0003327109430000101
Av＝A1v1+A2v2
Figure BDA0003327109430000102
In the above formula, λ1Dimensionless on-way drag coefficient, λ, of the first heat exchange tube section through which the first bypass branch flows2Dimensionless on-way drag coefficient, L, of the second heat exchange tube section through which the second bypass branch flows1Is the tube length, L, of the first heat exchange tube section2Is the tube length, xi, of the second heat exchange tube section1Is a dimensionless local resistance coefficient, xi, of the first heat exchange tube section2Is a dimensionless local resistance coefficient, v, of the second heat exchange tube section1Is the characteristic flow velocity, v, of the fluid in the first heat exchange tube section2The fluid characteristic flow rate of the second heat exchange tube section is ρ, which is the density of the refrigerant in the outdoor heat exchange tube 20.
A is the cross-sectional area of the outdoor heat exchange tube, A1The cross-sectional area of the heat exchange tube section through which the first bypass branch flows, A2Cross-sectional area, p, of the heat exchange tube section through which the second bypass branch flowsinIs the pressure, p, of the refrigerant flowing into the bypass branchoutThe pressure when the refrigerant flows out of the bypass branch, and alpha is a kinetic energy correction coefficient and is related to the velocity distribution of the pipe; v. ofinSpeed, v, of refrigerant flow into bypass branchoutIs the speed of refrigerant flowing out of the bypass branch, g is the gravitational acceleration, zinPotential energy z of refrigerant flowing into the bypass branchoutThe potential energy is the potential energy when the refrigerant flows out of the bypass branch, rho gz is the potential energy term, and the gas flowing in the heat exchange pipe can be ignored; h is the pressure head, Δ p is the pressure loss due to the on-way pressure and the local pressure, Δ p is ρ g (H)f+hj) ρ gH- Δ p is the actual pressure difference inside the outdoor heat exchange tube 20; in denotes a point a where the refrigerant flows in, and out denotes a point c where the refrigerant flows out.
Determining the frosting amount ratio of each heat exchange pipe section 200 after the outdoor heat exchanger 2 is shunted according to the refrigerant flow ratio, and combining an M-x distribution curve to obtain the design position of the bypass node of the outdoor heat exchanger 2.
In the embodiment of the present invention, the frosting amount range of the air conditioning system may also be determined according to the total heat exchange area and the heat exchange capacity of the outdoor heat exchanger 2 of the air conditioning system, so as to determine whether the bypass branch 101 needs to be arranged.
The heat exchange capacity of the heat exchanger generally has a design value, the heat exchange capacity of the heat exchanger is related to factors such as outdoor environment temperature and indoor load during actual operation, the total heat exchange area of the heat exchanger is fixed and calculated, if the total heat exchange area of the fin tube type heat exchanger is the sum of the fin area and the tube area, the heat exchange capacity and the heat exchange area of the heat exchangers of different air conditioner types are different, and the optimal frosting amount range, within which the heat exchange capacity of the air conditioner type cannot be deteriorated, is determined according to the corresponding heat exchange capacity and the size of the heat exchange area of each air conditioner type, so that the heat exchange capacity is prevented from being rapidly reduced due to serious frosting, and the air conditioning system is ensured to have higher heating energy efficiency.
In the specific implementation process of the embodiment of the invention, the amount of frosting determines the amount of heat used for defrosting, the larger the overall value of the range of the frosting amount is, that is, the more the frosting amount is, the more the heat needed for defrosting is, the more the refrigerant is needed, the larger the resistance in the outdoor heat exchange tube 20 is, specifically, in the heat exchange tubes with the same pipe diameter is, the more the refrigerant is, the larger the density of the refrigerant is, and the calculation formula of the on-way resistance and the local resistance is known, the larger the on-way resistance and the local resistance at this time is, the more the loss of the refrigerant is in the flow direction of the outdoor heat exchange tube 20 along the refrigerant, the heat used for heat exchange is gradually reduced, the defrosting efficiency of each heat exchange tube section 200 is different, and at this time, a bypass branch 101 is needed to be arranged to directly guide the refrigerant in the compressor 1 to the corresponding node of the heat exchange tube for heat exchange; when the frost formation amount is small, the influence of the resistance in the pipe on the refrigerant is small, and whether the bypass branch 101 is arranged or not is mainly determined by the pipe length L.
Wherein, when the frost formation amount is small, as shown in the above formula of on-way resistance and local resistance, the longer the tube length of the outdoor heat exchange tube 20 is, the larger the resistance thereof is, and at this time, even if the frost formation amount is small, the bypass branch 101 is required to be arranged to directly introduce the drainage in the compressor 1 to the corresponding heat exchange tube section 200.
Referring to fig. 1 to 2, the present invention provides an air conditioning system including a compressor 1, an outdoor heat exchanger 2, and an indoor heat exchanger 3 connected in series by pipes to form a refrigerant circulation pipe 100, the outdoor heat exchanger 2 including at least one outdoor heat exchange pipe 20, the outdoor heat exchange pipe 20 including at least two heat exchange pipe sections 200 communicated with each other, the air conditioning system including: at least one bypass branch 101, wherein one end of each bypass branch 101 is communicated with an outlet of the compressor 1, and the other end of each bypass branch 101 is connected with a bypass node 210 between two adjacent heat exchange pipe sections 200; and a plurality of temperature sensing parts 4, wherein each heat exchange pipe section 200 is provided with one temperature sensing part 4, so as to control the defrosting state of the air conditioning system according to the detection results of the plurality of temperature sensing parts 4.
The air conditioning system of the present invention includes a compressor 1, an outdoor heat exchanger 2, an indoor heat exchanger 3 connected in sequence by pipes to form a refrigerant circulation pipe 100, the outdoor heat exchanger 2 includes at least one outdoor heat exchange pipe 20, the outdoor heat exchange pipe 20 includes at least two heat exchange pipe sections 200 communicated with each other, the air conditioning system includes: at least one bypass branch 101, wherein one end of each bypass branch 101 is communicated with an outlet of the compressor 1, and the other end of each bypass branch 101 is connected with a bypass node 210 between two adjacent heat exchange pipe sections 200; and a plurality of temperature sensing parts 4, wherein each heat exchange pipe section 200 is provided with one temperature sensing part 4, so as to control the defrosting state of the air conditioning system according to the detection results of the plurality of temperature sensing parts 4. The air conditioning system is suitable for the defrosting and shunting method, the number of the bypass branches 101 determined by the defrosting and shunting method is used, and the refrigerant is led to the corresponding heat exchange pipe sections 200 through the shunting structure, so that the defrosting is synchronously performed at all positions of the outdoor heat exchanger 2, the defrosting speed and the defrosting heat utilization rate are improved, and the indoor thermal comfort is ensured.
Specifically, the number of the outdoor heat exchange tubes 20 is greater than two, and each outdoor heat exchange tube 20 has a plurality of bypass nodes 210 formed by two adjacent outdoor heat exchange tubes 20; the number of bypass branches 101 is plural, and the plurality of bypass branches 101 are connected to the corresponding bypass nodes 210 in one-to-one correspondence.
In an embodiment of the present invention, the air conditioning system further includes: a first expansion valve 5, the first expansion valve 5 being provided on a pipe section of the refrigerant circulation line 100 between the indoor heat exchanger 3 and the outdoor heat exchanger 2; and/or a second expansion valve 6, the second expansion valve 6 being arranged in the bypass branch 101.
In the specific implementation process of the embodiment of the invention, the exhaust gas of the air-conditioning compressor 1 passes through the indoor heat exchanger 3 and then enters the outdoor heat exchanger 2 from the refrigerant inlet of the outdoor heat exchanger 2 through the first expansion valve 5 to defrost.
Specifically, the air conditioning system further includes: the bypass control valve 7 is arranged on the bypass branch 101, so that the on-off of the bypass branch 101 is controlled; and/or a refrigerant control valve 8, wherein the refrigerant control valve 8 is arranged on the refrigerant circulating pipeline 100 to control the on-off of the refrigerant circulating pipeline 100.
In the implementation of the embodiment of the present invention, the bypass control valve 7 is used to control the opening and closing of the bypass branch 101, and the second expansion valve 6 is used to control the adjustment of the flow rate of the bypass branch 101.
In an embodiment of the present invention, there are a plurality of heat exchange tube segments 200 and a plurality of bypass legs 101, each heat exchange tube segment 200 communicating with at least one bypass leg 101.
Referring to fig. 3, taking only one bypass branch 101 as an example, the present invention provides an air conditioning control method, which is applicable to the air conditioning system, where the air conditioning system includes a defrosting mode, and when the air conditioning system is in the defrosting mode, the air conditioning control method includes: detecting the tube temperature of each heat exchange tube section 200 of the outdoor heat exchanger 2 of the air conditioning system in real time; the on-off state of the bypass branch 101 is adjusted according to the magnitude of the tube temperature of each heat exchange tube section 200 to adjust the defrosting state of the defrosting mode.
Specifically, the method for controlling the on-off state of the bypass branch 101 includes: when the pipe temperature of at least one heat exchange pipe section 200 of the air conditioning system is higher than a first preset temperature, controlling all bypass branches 101 of the air conditioning system to be in a disconnected state so that the air conditioning system exits a defrosting mode; otherwise, the bypass branch 101 is controlled to maintain the conducting state, so that the air conditioning system continues to be in the defrosting mode.
When the tube temperature of at least one heat exchange tube section 200 of the air conditioning system is higher than a first preset temperature, the outdoor heat exchanger 2 has been defrosted and the outdoor heat exchange tube 20 is dry, and then defrosting is finished, and the defrosting operation state is exited and a heating operation state is entered.
Further, the air conditioner control method further includes: acquiring the temperature rise rates of at least two heat exchange tube sections 200 of the air conditioning system; when the pipe temperatures of all the heat exchange pipe sections 200 of the air conditioning system are less than or equal to a first predetermined temperature, the operation state of the defrosting mode is adjusted according to the magnitude of the temperature rise rates of at least two heat exchange pipe sections 200.
In an embodiment of the present invention, the at least two heat exchange tube sections 200 comprise a first heat exchange tube section 201 and a second heat exchange tube section 202 arranged in sequence and adjacently in a refrigerant flow direction, and adjusting the operation state of the defrost mode comprises: the rate of temperature rise V of the second heat exchange tube segment 200TdTemperature rise rate V with the first heat exchange tube segment 200TbCarrying out ratio operation to obtain the temperature rise rate ratio alpha-VTd/VTb(ii) a And adjusting the running state of the defrosting mode according to the temperature rise rate ratio alpha.
Specifically, when the tube temperatures of all the heat exchange tube sections 200 of the air conditioning system are less than or equal to the first predetermined temperature, it indicates that the outdoor heat exchanger 2 is still frosted and defrosting is not finished, and it is continuously determined that the outer tube temperature rise rate ratio α is (V ═ VTd/VTb) With a preset value beta of the temperature rise rate ratio (with the tube temperature ratio T of each heat exchange tube section 200 of the outdoor heat exchanger at the start of defrosting)cd/TbcRelated).
In an embodiment of the present invention, adjusting the operation state of the defrost mode includes: when the temperature rise rate ratio alpha is smaller than beta-epsilon, increasing the unit refrigerant circulation of a bypass branch 101 communicated with a bypass node 210 between the first heat exchange pipe section 201 and the second heat exchange pipe section 202, or reducing the unit refrigerant circulation of the first heat exchange pipe section 201, or increasing the rotating speed of an inner fan of an air conditioner indoor unit of the air conditioning system; when the value range of the temperature rise rate ratio alpha is that beta-epsilon is not less than alpha and not more than beta + epsilon, controlling the air conditioning system to maintain the current defrosting operation state, and continuously comparing the pipe temperature of each heat exchange pipe section 200 with the first preset temperature; when the temperature rise rate ratio alpha is larger than beta + epsilon, the unit refrigerant circulation of the bypass branch 101 communicated with the bypass node 210 between the first heat exchange pipe section 201 and the second heat exchange pipe section 202 is reduced, or the unit refrigerant circulation of the first heat exchange pipe section 201 is increased, or the rotating speed of an inner fan of an air conditioner indoor unit of the air conditioning system is reduced.
As shown in fig. 1 and 2, the first heat exchange tube section 201 is the bc section in the figure and the second heat exchange tube section 202 is the cd section in the figure. Bypass node 210 is point c in the figure.
Specifically, when the temperature rise rate ratio α is smaller than β -e, it indicates that the defrosting rate of the second heat exchange tube section 202(cd) is slower than that of the first heat exchange tube section 201(bc), the opening of the second expansion valve 6 is increased to perform large adjustment, and the opening of the first expansion valve 5 is decreased to perform fine adjustment (or the rotation speed n of the internal fan is increased to perform fine adjustment)2) Thus, the defrosting heat of the cd section is increased until alpha is beta, and synchronous defrosting is realized; and controlling the running frequency f of the compressor according to the adjusted phase currents of the first expansion valve 5, the second expansion valve 6 and the compressor.
When the value range of the temperature rise rate ratio alpha is that beta-epsilon is not less than alpha and not more than beta + epsilon, the defrosting of the two heat exchange tube sections 200 of the outdoor heat exchanger 2 is synchronous, and at the moment, the air conditioner keeps the current state to continue to operate;
when the temperature rise rate ratio alpha is larger than beta + epsilon, the rate defrosting of the cd section is faster than the defrosting of the bc section, the opening degree of the second expansion valve 6 is reduced to perform large adjustment, the opening degree of the first expansion valve 5 is increased to perform fine adjustment (or the rotating speed n2 of the inner fan is reduced), so that the defrosting heat of the ac section is increased until the alpha is beta, and the synchronous defrosting is realized; and controlling the running frequency f of the compressor according to the adjusted phase currents of the first expansion valve 5, the second expansion valve 6 and the compressor.
Preferably, the first expansion valve 5 is a throttle electronic expansion valve, and the second expansion valve 6 is an electronic expansion valve.
Specifically, the method of adjusting the unit refrigerant circulation amount of the bypass branch 101 includes: increasing or decreasing the opening of the bypass control valve 7 on the bypass branch 101; and/or adjusting the unit refrigerant flow capacity of the first heat exchange tube section 201 comprises: the opening degree of the refrigerant control valve 8 on the refrigerant circulation line 100 is increased or decreased.
As shown in fig. 3, when the temperature rise rate ratio α is smaller than β - ∈, the opening degree of the second expansion valve 6 is increased to increase the unit refrigerant circulation amount of the bypass branch 101 communicating with the bypass node 210 between the first heat exchange tube section 201 and the second heat exchange tube section 202, or the opening degree of the first expansion valve 5 is decreased to decrease the unit refrigerant circulation amount of the first heat exchange tube section 201, or the air conditioner indoor unit of the air conditioning system is increased in air conditioner inner fan rotation speed.
Further, after the unit refrigerant flow rate of the bypass branch 101, or the unit refrigerant flow rate of the second heat exchange tube section 202, or the rotational speed of the internal fan is adjusted, the operation frequency of the compressor 1 of the air conditioning system is controlled according to the adjusted opening sizes of the bypass control valve 7 and the refrigerant control valve 8, and the phase current of the compressor 1.
In an embodiment of the present invention, after the air conditioning system starts the defrosting mode, the air conditioning control method includes: the bypass control valve 7 is opened to put the air conditioning system into defrost mode operation.
In an embodiment of the present invention, before the air conditioning system enters the defrosting mode, the air conditioning control method further includes: detecting and recording outdoor ambient temperature TwIndoor ambient temperature TnOutdoor tube temperature of each heat exchange tube section 200 of the outdoor heat exchanger 2 of the air conditioning system, indoor tube temperature T of the indoor heat exchange tube of the indoor heat exchanger 3 of the air conditioning systemsThe rotating speed of an outer fan of the air conditioning system, the rotating speed of an inner fan of the air conditioning system and the opening degree of each valve.
Specifically, the air conditioning control method of the present invention performs the load operation in the following order:
according to the outdoor ambient temperature TwThe tube temperature T of the second heat exchange tube section 202bcThe tube temperature T of the first heat exchange tube section 201cdConfirming the defrost frequency f and the external fan speed n of the compressor 11And controlling the compressor 1 to operate at a predetermined frequency to control the external fanOperating at a preset rotating speed;
according to Tw、Tbc、TcdF, phase current I (or power), and controlling and increasing the opening of a throttle valve of the air conditioning system (namely a first expansion valve 5);
detecting and recording the accumulated defrosting time t, wherein the defrosting time is greater than the preset time t1When the valve is opened, the bypass control valve 7 of the bypass branch 101 is controlled;
continue according to Tw、TnThe tube temperature difference Δ T ═ T of each heat exchange tube segment 200 of the outdoor heat exchange tube 20cd-TbcConfirming the opening degree of the bypass flow rate adjusting valve (namely, the second expansion valve 6) by the defrosting frequency f of the compressor 1 and the opening degree of the first expansion valve 5;
according to the pipe temperature T of the heat exchange pipe of the indoor heat exchanger 3sThe tube temperature T of each heat exchange tube section 200 of the outdoor heat exchanger 2bc、TcdThe frequency f of the compressor and the opening degree of the second expansion valve 6, the preset rotating speed of the inner fan is confirmed, and the inner fan is controlled to operate according to the preset rotating speed.
After the actions are finished, the air conditioner is switched to defrosting operation, one path of exhaust gas of the compressor passes through the indoor heat exchanger 3 and the first expansion valve 5 and then enters the first heat exchange pipe section 201(bc section) of the outdoor heat exchanger 2 for defrosting, and the rotating speed n of the inner fan is controlled2The opening degree of the first expansion valve 5 controls the defrosting heat of the flow path; the other path of the exhaust gas of the compressor 1 is bypassed to the outdoor heat exchanger 2 after passing through a bypass control valve 7 and a second expansion valve 6, is mixed with the heating agent after the defrosting of the first heat exchange tube section 201(bc section) is finished, enters the second heat exchange tube section (cd) of the outdoor heat exchanger 2 to finish the defrosting, and flows back to the compressor 1 from the outlet of the outdoor heat exchanger 2 to finish a defrosting cycle.
In the embodiment of the invention, after the air conditioner is switched to the defrosting state to operate, the pipe temperature of each heat exchange pipe section 200 of the outdoor heat exchanger 2 of the air conditioning system is monitored and recorded in real time in the defrosting process of the air conditioner, and specifically, the pipe temperature T of the first heat exchange pipe section 201 is monitoredbcAnd the tube temperature T of the second heat exchange tube section 202cd。
According to another embodiment of the present invention, the scheme without the second expansion valve 6 is within the protection scope, wherein the bypass control valve 7 controls the opening and closing of the bypass branch 101, the flow rate and defrosting heat distribution are controlled by the first expansion valve 5 and the inner fan, and the bypass point c is closer to the point b, and the control method is not changed.
From the above description, it can be seen that the above-described embodiments of the present invention achieve the following technical effects:
the defrosting shunting method provided by the invention comprises the following steps: determining a heat exchange difference value delta k between the maximum heat exchange coefficient and the minimum heat exchange coefficient of an outdoor heat exchange tube 20 of the outdoor heat exchanger 2 and the tube length L of the outdoor heat exchange tube 20; judging the frost formation amount or the difference of the heat exchange amount along the pipeline flowing direction of the outdoor heat exchange pipe 20 according to the heat exchange difference value delta k and the pipe length L so as to determine the number n of the bypass branches 101 communicated with the outdoor heat exchange pipe 20; one end of the bypass branch 101 is communicated with an outlet of the air conditioning system, and the other end of the bypass branch 101 is communicated with the middle part of the outdoor heat exchange tube 20; n is an integer greater than or equal to 0. In this way, the number of the bypass branches 101 is determined by the defrosting and shunting method of the present invention to shunt the refrigerant of the outdoor heat exchanger 2 in the air conditioning system, so that each heat exchange tube segment 200 of the outdoor heat exchange tube 20 of the outdoor heat exchanger 2 can be defrosted synchronously, thereby solving the problems of poor synchronous defrosting effect and low defrosting efficiency in the prior art.
The air conditioning system of the present invention includes a compressor 1, an outdoor heat exchanger 2, an indoor heat exchanger 3 connected in sequence by pipes to form a refrigerant circulation pipe 100, the outdoor heat exchanger 2 includes at least one outdoor heat exchange pipe 20, the outdoor heat exchange pipe 20 includes at least two heat exchange pipe sections 200 communicated with each other, the air conditioning system includes: at least one bypass branch 101, wherein one end of each bypass branch 101 is communicated with an outlet of the compressor 1, and the other end of each bypass branch 101 is connected with a bypass node 210 between two adjacent heat exchange pipe sections 200; and a plurality of temperature sensing parts 4, wherein each heat exchange pipe section 200 is provided with one temperature sensing part 4, so as to control the defrosting state of the air conditioning system according to the detection results of the plurality of temperature sensing parts 4. The air conditioning system is suitable for the defrosting shunting method, and the number of the bypass branches 101 determined by the defrosting shunting method is used for synchronously defrosting at each position of the outdoor heat exchanger through the shunting structure, so that the defrosting speed and the defrosting heat utilization rate are improved, and the indoor thermal comfort is ensured.
In addition, a defrosting control method is proposed based on the system as follows: the total resistance of the system and the flow of the refrigerant are predicted by detecting the opening of each valve, and the running frequency of the compressor 1 is controlled to improve the total defrosting heat to the maximum extent. The defrosting heat is optimized and allocated in real time by detecting and recording the temperature change rate of each temperature sensing part 4 on the outdoor heat exchanger 2 in real time, controlling the valve opening of each bypass branch 101, the rotating speed of the inner fan, the rotating speed of the outer fan and the like, so that the defrosting synchronism of the outdoor heat exchanger 2 is ensured, and the defrosting efficiency is improved.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (23)

1. A defrosting and shunting method is used for shunting a refrigerant of an outdoor heat exchanger (2) in an air conditioning system, and is characterized by comprising the following steps:
determining a heat exchange difference value delta k between the maximum heat exchange coefficient and the minimum heat exchange coefficient of an outdoor heat exchange pipe (20) of the outdoor heat exchanger (2) and the pipe length L of the outdoor heat exchange pipe (20);
judging the difference of the frost formation amount or the heat exchange amount along the pipeline flowing direction of the outdoor heat exchange pipe (20) according to the heat exchange difference value delta k and the pipe length L so as to determine the number n of bypass branches (101) communicated with the outdoor heat exchange pipe (20);
one end of the bypass branch (101) is communicated with an outlet of the air conditioning system, and the other end of the bypass branch (101) is communicated with the middle part of the outdoor heat exchange tube (20); n is an integer greater than or equal to 0.
2. The defrost diversion method of claim 1, further comprising:
and determining the heat exchange coefficient k of each position of each outdoor heat exchange tube (20) of the outdoor heat exchanger (2) according to the parameters of the outdoor heat exchanger (2) so as to determine the maximum heat exchange coefficient and the minimum heat exchange coefficient of the outdoor heat exchange tube (20).
3. The defrost diversion method of claim 1, further comprising, after determining the heat transfer coefficient k for each location of each outdoor heat exchange tube (20):
drawing a heat exchange coefficient k-x curve of the corresponding outdoor heat exchange tube (20);
determining the maximum heat exchange coefficient and the minimum heat exchange coefficient of the outdoor heat exchange tube (20) according to the heat exchange coefficient k-x curve;
in the heat exchange coefficient k-x curve, the origin of coordinates is a refrigerant inlet point when the air conditioning system is in heating operation, the abscissa x represents the tube length of the outdoor heat exchange tube (20), the direction of the abscissa x is the flowing direction of the refrigerant in the outdoor heat exchange tube (20), and the ordinate k represents the heat exchange coefficient k.
4. Defrost diversion method according to claim 1, characterized in that after determining the number n of bypass branches (101), the defrost diversion method further comprises:
determining the ratio of the frosting amount of a plurality of heat exchange tube sections (200) of the outdoor heat exchange tube (20) after being divided by the n bypass branches (101) according to the flow resistance of the n bypass branches (101);
the position of a bypass node (210) of the outdoor heat exchange tube (20) for communicating with the bypass branch (101) is determined according to the heat exchange amount magnitude of each position of the outdoor heat exchange tube (20) in the refrigerant flow direction and the ratio of the frost formation amounts of the plurality of heat exchange tube sections (200).
5. The defrost diversion method of claim 4, further comprising:
when the air conditioning system is in a heating mode, calculating the heat exchange quantity of each position of the outdoor heat exchange pipe (20) along the flowing direction of the refrigerant;
and the circulation resistance of the n bypass branches (101) is obtained according to the heat exchange quantity of each position of the outdoor heat exchange pipe (20) along the flowing direction of the refrigerant.
6. The defrost diversion method according to claim 5, wherein after deriving the magnitude of the heat exchange amount at each position of the outdoor heat exchange tube (20) in the refrigerant flow direction, said defrost diversion method further comprises:
an M-x distribution curve of the frosting amount M along the tube length direction of the outdoor heat exchange tube (20) is obtained, and the position of a bypass node (210) of the outdoor heat exchange tube (20) is determined according to the M-x distribution curve and the ratio of the frosting amounts of the plurality of heat exchange tube sections (200).
7. Defrost diversion method according to claim 1, characterized in that the method of determining the number n of bypass branches (101) communicating with the outdoor heat exchange tube (20) comprises:
when the delta k is smaller than a first preset heat exchange coefficient k1Then, the actual length L and the first preset length L of the outdoor heat exchange tube (20) are judged1The magnitude relationship between them;
when the actual pipe length L is less than or equal to the first preset pipe length L1When n is 0, n is taken.
8. Defrost diversion method according to claim 1, characterized in that the method of determining the number n of bypass branches (101) communicating with the outdoor heat exchange tube (20) comprises:
when the delta k is more than or equal to a first preset heat exchange coefficient k1And is less than or equal to a second preset heat exchange coefficient k2Then, the actual length L and the second preset length L of the outdoor heat exchange tube (20) are judged2The magnitude relationship between them; the second preset pipe length L2Is less than the first preset pipe length L1；
When the actual pipe length L is less than or equal to the secondTwo preset tube lengths L2When n is 0; otherwise, according to the actual tube length L and the first preset heat exchange coefficient k1Obtaining the minimum number of bypass branches (101) communicated with the outdoor heat exchange tube (20), and according to the actual tube length L and the second preset heat exchange coefficient k2And obtaining the maximum value of the bypass branches (101) communicated with the outdoor heat exchange pipe (20), and determining the number n of the bypass branches (101) according to the delta k.
9. Defrost diversion method according to claim 1, characterized in that the method of determining the number n of bypass branches (101) communicating with the outdoor heat exchange tube (20) comprises:
when delta k is larger than a second preset heat exchange coefficient k2When the heat exchange pipe section (200) is divided into a first heat exchange pipe section (201) and a second heat exchange pipe section (202), and the maximum heat exchange coefficient difference value of the first heat exchange pipe section (201) and the second heat exchange pipe section (202) is smaller than k2；
And the number n of bypass branches (101) communicated with the branches of the first heat exchange pipe section (201) and the second heat exchange pipe section (202) is judged according to the maximum heat exchange coefficient difference value and the pipe section length of the first heat exchange pipe section (201) and the second heat exchange pipe section (202).
10. An air conditioning system comprising a compressor (1), an outdoor heat exchanger (2), and an indoor heat exchanger (3) that are sequentially pipe-connected to form a refrigerant circulation line (100), the outdoor heat exchanger (2) including at least one outdoor heat exchange pipe (20), characterized in that the outdoor heat exchange pipe (20) includes at least two heat exchange pipe sections (200) that are communicated with each other, the air conditioning system comprising:
at least one bypass branch (101), one end of each bypass branch (101) is communicated with an outlet of the compressor (1), and the other end of each bypass branch (101) is connected with a bypass node (210) between two adjacent heat exchange tube sections (200);
the temperature sensing parts (4) are arranged on the heat exchange pipe sections (200) respectively, and the temperature sensing parts (4) are used for controlling the defrosting state of the air conditioning system according to the detection results of the temperature sensing parts (4).
11. The air conditioning system of claim 10,
the number of the heat exchange tube sections (200) is more than two, and each outdoor heat exchange tube (20) is provided with a plurality of bypass nodes (210) formed by two adjacent heat exchange tube sections (200); the number of the bypass branches (101) is multiple, and the multiple bypass branches (101) are connected with the corresponding bypass nodes (210) in a one-to-one correspondence manner.
12. The air conditioning system of claim 10, further comprising:
a first expansion valve (5), the first expansion valve (5) being disposed on a pipe section of the refrigerant circulation line (100) between the indoor heat exchanger (3) and the outdoor heat exchanger (2); and/or
A second expansion valve (6), the second expansion valve (6) being disposed on the bypass branch (101).
13. The air conditioning system of claim 10, further comprising:
the bypass control valve (7) is arranged on the bypass branch (101) to control the on-off of the bypass branch (101); and/or
A refrigerant control valve (8), wherein the refrigerant control valve (8) is arranged on the refrigerant circulating pipeline (100) to control the on-off of the refrigerant circulating pipeline (100).
14. The air conditioning system as recited in claim 10, wherein said outdoor heat exchange tube (20) is plural, said bypass branch (101) is plural, and each of said outdoor heat exchange tubes (20) communicates with at least one of said bypass branch (101).
15. An air conditioning control method applied to the air conditioning system of any one of claims 10 to 14, the air conditioning system including a defrost mode, characterized in that when the air conditioning system is in the defrost mode, the air conditioning control method comprises:
detecting the tube temperature of each heat exchange tube section (200) of an outdoor heat exchanger (2) of the air conditioning system in real time;
and adjusting the on-off state of the bypass branch (101) according to the pipe temperature of each heat exchange pipe section (200) so as to adjust the defrosting state of the defrosting mode.
16. The air conditioner controlling method according to claim 15, wherein the method of controlling the on-off state of the bypass branch (101) comprises:
controlling all bypass branches (101) of the air conditioning system in an off-state to cause the air conditioning system to exit the defrost mode when a tube temperature of at least one heat exchange tube section (200) of the air conditioning system is greater than a first predetermined temperature; otherwise, controlling the bypass branch (101) to maintain a conducting state so as to enable the air conditioning system to be continuously in the defrosting mode.
17. The air conditioning control method according to claim 15, further comprising:
acquiring the temperature rise rates of at least two heat exchange tube sections (200) of the air conditioning system;
when the pipe temperatures of all the heat exchange pipe sections (200) of the air conditioning system are less than or equal to a first preset temperature, the operation state of the defrosting mode is adjusted according to the temperature rise rates of the at least two heat exchange pipe sections (200).
18. The air conditioning control method according to claim 17, wherein the at least two heat exchange tube sections (200) include a first heat exchange tube section (201) and a second heat exchange tube section (202) disposed sequentially and adjacently in a refrigerant flow direction, and adjusting the operating state of the defrost mode includes:
setting a temperature rise rate V of the second heat exchange tube segment (202)TdTemperature rise with the first heat exchange tube section (201)Velocity VTbCarrying out ratio operation to obtain the temperature rise rate ratio alpha-VTd/VTb；
And adjusting the running state of the defrosting mode according to the temperature rise rate ratio alpha.
19. The air conditioner control method according to claim 18, wherein adjusting the operation state of the defrost mode includes:
when the temperature rise rate ratio alpha is smaller than beta-epsilon, increasing the unit refrigerant circulation of the bypass branch (101) communicated with a bypass node (210) between the first heat exchange pipe section (201) and the second heat exchange pipe section (202), or reducing the unit refrigerant circulation of the first heat exchange pipe section (201), or increasing the rotating speed of an inner fan of an air-conditioning indoor unit of the air-conditioning system;
when the value range of the temperature rise rate ratio alpha is beta-epsilon is not less than alpha and not more than beta + epsilon, controlling the air conditioning system to maintain the current defrosting operation state, and continuously comparing the pipe temperature of each heat exchange pipe section (200) with the first preset temperature;
when the temperature rise rate ratio alpha is larger than beta + epsilon, reducing the unit refrigerant circulation of the bypass branch (101) communicated with a bypass node (210) between the first heat exchange pipe section (201) and the second heat exchange pipe section (202), or increasing the unit refrigerant circulation of the first heat exchange pipe section (201), or reducing the rotating speed of an inner fan of an air-conditioning indoor unit of the air-conditioning system.
20. The air conditioning control method according to claim 19,
the method for adjusting the unit refrigerant flow rate of the bypass branch (101) comprises the following steps: -increasing or decreasing the opening of a bypass control valve (7) located on the bypass branch (101); and/or
The method of adjusting the unit refrigerant flow capacity of the first heat exchange tube section (201) comprises: increasing or decreasing the opening degree of a refrigerant control valve (8) on the refrigerant circulation line (100).
21. The air conditioning control method according to claim 20, wherein after adjusting the unit refrigerant circulation amount of the bypass branch (101), or the unit refrigerant circulation amount of the second heat exchange pipe section (202), or the rotation speed of the inner fan, the operation frequency of a compressor (1) of the air conditioning system is controlled according to the adjusted opening sizes of the bypass control valve (7) and the refrigerant control valve (8), and the phase current of the air conditioning system.
22. The air conditioning control method according to claim 21, wherein after the air conditioning system turns on the defrost mode, the air conditioning control method comprises:
opening the bypass control valve (7) to enable the air conditioning system to enter a defrost mode of operation.
23. The air conditioning control method according to claim 22, wherein before the air conditioning system enters the defrost mode operation, the air conditioning control method further comprises:
detecting and recording outdoor ambient temperature TwIndoor ambient temperature TnThe outdoor tube temperature of each heat exchange tube section (200) of the outdoor heat exchanger (2) of the air-conditioning system and the indoor tube temperature T of the indoor heat exchange tube of the indoor heat exchanger (3) of the air-conditioning systemsThe rotating speed of an outer fan of the air conditioning system and the rotating speed of an inner fan of the air conditioning system.
CN202111267011.2A 2021-10-28 2021-10-28 Defrosting shunting method Active CN113865005B (en)

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