CN112944586A - Control method of multi-split air conditioning system - Google Patents

Control method of multi-split air conditioning system Download PDF

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Publication number
CN112944586A
CN112944586A CN202110226662.0A CN202110226662A CN112944586A CN 112944586 A CN112944586 A CN 112944586A CN 202110226662 A CN202110226662 A CN 202110226662A CN 112944586 A CN112944586 A CN 112944586A
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China
Prior art keywords
pressure drop
indoor unit
conditioning system
split air
control method
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CN202110226662.0A
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CN112944586B (en
Inventor
周林林
李旭
夏鹏
冯维庆
毛守博
卢大海
刘晓凯
刘汇泉
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Qingdao Haier Air Conditioner Gen Corp Ltd
Qingdao Haier Air Conditioning Electric Co Ltd
Haier Smart Home Co Ltd
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Qingdao Haier Air Conditioner Gen Corp Ltd
Qingdao Haier Air Conditioning Electric Co Ltd
Haier Smart Home Co Ltd
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Priority to CN202110226662.0A priority Critical patent/CN112944586B/en
Publication of CN112944586A publication Critical patent/CN112944586A/en
Priority to PCT/CN2022/077983 priority patent/WO2022183986A1/en
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24FAIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00Control or safety arrangements
    • F24F11/30Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
    • F24F11/32Responding to malfunctions or emergencies
    • F24F11/36Responding to malfunctions or emergencies to leakage of heat-exchange fluid
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24FAIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00Control or safety arrangements
    • F24F11/50Control or safety arrangements characterised by user interfaces or communication
    • F24F11/61Control or safety arrangements characterised by user interfaces or communication using timers
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24FAIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00Control or safety arrangements
    • F24F11/62Control or safety arrangements characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
    • F24F11/63Electronic processing
    • F24F11/64Electronic processing using pre-stored data
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24FAIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00Control or safety arrangements
    • F24F11/62Control or safety arrangements characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
    • F24F11/63Electronic processing
    • F24F11/65Electronic processing for selecting an operating mode
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24FAIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00Control or safety arrangements
    • F24F11/70Control systems characterised by their outputs; Constructional details thereof
    • F24F11/72Control systems characterised by their outputs; Constructional details thereof for controlling the supply of treated air, e.g. its pressure
    • F24F11/74Control 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
    • F24F11/77Control 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
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24FAIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00Control or safety arrangements
    • F24F11/70Control systems characterised by their outputs; Constructional details thereof
    • F24F11/80Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air
    • F24F11/83Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers
    • F24F11/84Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers using valves
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24FAIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00Control or safety arrangements
    • F24F11/88Electrical aspects, e.g. circuits
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24FAIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F2140/00Control inputs relating to system states
    • F24F2140/10Pressure
    • F24F2140/12Heat-exchange fluid pressure
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02BCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/70Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Fuzzy Systems (AREA)
  • Mathematical Physics (AREA)
  • Human Computer Interaction (AREA)
  • Fluid Mechanics (AREA)
  • Air Conditioning Control Device (AREA)

Abstract

The invention belongs to the technical field of air conditioning, and aims to solve the problems that the existing refrigerant leakage detection schemes have certain hysteresis and cannot realize real-time detection of the whole pipeline system. The invention provides a control method of a multi-split air conditioning system, which comprises the following steps: acquiring actual pressure drop of a main pipeline, actual pressure drop of an outdoor unit and actual pressure drop of each indoor unit, and comparing the actual pressure drops with respective theoretical pressure drops; and if the actual pressure drop of the main pipeline is greater than the theoretical pressure drop of the main pipeline and lasts for a set time, or the actual pressure drop of the outdoor unit is greater than the theoretical pressure drop of the outdoor unit and lasts for a set time, or the actual pressure drop of any indoor unit is greater than the theoretical pressure drop of the indoor unit and lasts for a set time, judging that the refrigerant leakage of the multi-split air-conditioning system occurs. The invention can carry out all-around and real-time detection on the pipeline of the multi-split air-conditioning system, does not cause the situation of detection lag, and improves the operation safety of the multi-split air-conditioning system.

Description

Control method of multi-split air conditioning system
Technical Field
The invention belongs to the technical field of air conditioning, and particularly provides a control method of a multi-split air conditioning system.
Background
The air conditioner, namely an air conditioner, can adjust and control the temperature, the humidity and the cleanliness of ambient air in a building, and provides convenience for the life of people. Air conditioning systems are classified into two major categories, comfort air conditioning and process air conditioning. The comfortable air conditioner has proper temperature requirement, comfortable environment and no strict requirement on the regulation precision of temperature and humidity, and is widely applied to houses, offices, markets and the like; the process air conditioner has certain requirements on temperature regulation precision, has higher requirements on air cleanliness, and is used for electronic device production workshops, precision instrument production workshops, computer rooms and the like.
The existing air conditioning system, especially a large-capacity commercial air conditioner, has system complexity and large-capacity characteristics, which determine that the flow path is usually long and the number of welding points is large, while the long flow path and the multiple welding points easily cause leakage of system refrigerant (refrigerant), and the aging of the air conditioning components during long-time operation increases the risk of refrigerant leakage. The refrigerant leakage causes the refrigerant charge amount of the system to be reduced, the pressure ratio of the compressor is easily increased, the exhaust temperature is too high, the compressor exceeds the normal operation range, the compressor is damaged, and meanwhile, the refrigerating and heating capacity of the indoor unit is reduced; the refrigerants used in the prior art, such as R410A, R134A and R32, have certain destructive effect on the ozone layer and generate greenhouse effect which aggravates global warming to a certain extent, and more importantly, some refrigerants have flammability and explosiveness, and once leakage occurs, the refrigerants seriously harm the personal and property safety. The existing refrigerant leakage detection scheme has certain hysteresis and cannot realize real-time detection of the whole pipeline system.
Therefore, there is a need in the art for a new control method of a multi-split air conditioning system to solve the above problems.
Disclosure of Invention
In order to solve the above problems in the prior art, that is, to solve the problems that the existing refrigerant leakage detection schemes all have a certain hysteresis and cannot realize real-time detection of the whole pipeline system, the present invention provides a control method of a multi-split air conditioning system, wherein the multi-split air conditioning system includes an outdoor unit and a plurality of indoor units, the indoor units are connected with the outdoor unit through a main pipeline, and the control method includes: acquiring the actual pressure drop of the main pipeline, the actual pressure drop of the outdoor unit and the actual pressure drop of each indoor unit; comparing the actual pressure drop of the main pipeline with the theoretical pressure drop of the main pipeline, comparing the actual pressure drop of the outdoor unit with the theoretical pressure drop of the outdoor unit, and comparing the actual pressure drop of each indoor unit with the respective theoretical pressure drop of each indoor unit; and if the actual pressure drop of the main pipeline is greater than the theoretical pressure drop of the main pipeline and lasts for a set time, or the actual pressure drop of the outdoor unit is greater than the theoretical pressure drop of the outdoor unit and lasts for the set time, or the actual pressure drop of any indoor unit is greater than the theoretical pressure drop of the indoor unit and lasts for the set time, judging that the refrigerant leakage of the multi-split air-conditioning system occurs.
In a preferred embodiment of the control method, after the step of determining that the refrigerant leakage occurs in the multi-split air conditioning system, the control method further includes: further determining the position of refrigerant leakage; and executing corresponding control operation according to the determination result.
In a preferred embodiment of the above control method, the step of "executing the corresponding control operation according to the determination result" includes: and if the position where the refrigerant leakage occurs comprises the outdoor unit or the main pipeline, stopping the whole multi-split air-conditioning system.
In a preferred embodiment of the above control method, the control method further includes, at the same time as or after the step of "stopping the entire multi-split air conditioning system", the step of: and alarming and displaying the leakage interval.
In a preferred embodiment of the above control method, the step of "executing the corresponding control operation according to the determination result" includes: if the position where the refrigerant leakage occurs only comprises one or more indoor units, judging whether the indoor unit with the refrigerant leakage is started or not; if the indoor unit with the refrigerant leakage is started, closing a valve group of the indoor unit with the refrigerant leakage and adjusting a fan of the indoor unit to the maximum air speed for operation; and if the indoor unit with the refrigerant leakage is shut down, starting a fan of the indoor unit with the refrigerant leakage and adjusting the fan to the maximum air speed for operation.
In a preferred technical solution of the above control method, at the same time as or after the step of "closing a valve group of an indoor unit in which refrigerant leakage occurs and adjusting a fan of the indoor unit to a maximum air speed operation", the control method further includes: and alarming and displaying the leakage interval.
In a preferred technical solution of the above control method, at the same time or after the step of "turning on a fan of an indoor unit having refrigerant leakage and adjusting to a maximum wind speed for operation", the control method further includes: and alarming and displaying the leakage interval.
In a preferred technical solution of the above control method, the theoretical pressure drop of the main pipe is determined according to a current operation mode of the multi-split air conditioning system, a compressor frequency of the multi-split air conditioning system, the number of the indoor units, an installation position of the outdoor unit, and a pipe diameter and a length of the main pipe.
In a preferred technical solution of the control method, the theoretical pressure drop of the outdoor unit is determined according to a current operation mode of the multi-split air conditioning system, a frequency of a compressor of the multi-split air conditioning system, and a pipe diameter and a length of a pipe section of the outdoor unit.
In a preferred technical scheme of the control method, the theoretical pressure drop of each indoor unit is determined according to the current operation mode of the multi-split air-conditioning system, the frequency of a compressor of the multi-split air-conditioning system, and the pipe diameter and the length of a pipe section of the indoor unit.
In the preferred technical scheme of the invention, the actual pressure drop of the main pipeline, the actual pressure drop of the outdoor unit and the actual pressure drop of each indoor unit are obtained and compared with the respective corresponding theoretical pressure drops, and the pipelines of the whole multi-split air-conditioning system can be detected in all directions according to the comparison result, so that whether refrigerant leakage occurs or not is judged, the detection accuracy is improved, the refrigerant leakage condition can be detected in real time, the condition of detection delay is avoided, the operation of the multi-split air-conditioning system is prevented from being influenced, the environmental protection is prevented from being influenced, and the operation safety of the multi-split air-conditioning system is improved.
Furthermore, the actual refrigerant leakage position can be determined according to the actual pressure drop of the main pipeline, the actual pressure drop of the outdoor unit and the comparison result of the actual pressure drop of each indoor unit and the corresponding theoretical pressure drop, and corresponding control strategies are provided according to the difference of the actual refrigerant leakage positions, so that the normal operation of the multi-split air-conditioning system is ensured, meanwhile, maintenance personnel can conveniently and specifically maintain the multi-split air-conditioning system, the maintenance efficiency is improved, the multi-split air-conditioning system is prevented from being stopped for a long time, and further the normal use of users is influenced.
Further, if the position where the refrigerant leakage occurs includes the outdoor unit or the main pipeline, it is determined that the heat exchange of all the indoor units is affected, and at this time, the whole multi-split air conditioning system is stopped, and then the multi-split air conditioning system can be continuously used after being maintained.
Further, if the position where the refrigerant leakage occurs only comprises the indoor unit, it is determined that the outdoor unit and the main pipeline are not affected, except that the indoor unit where the refrigerant leakage occurs cannot perform normal heat exchange operation, other indoor units without the refrigerant leakage can still perform normal operation, at this time, if the indoor unit where the refrigerant leakage occurs is started, the valve group is closed to prevent the refrigerant from further flowing into the indoor unit and large-area refrigerant leakage occurs, meanwhile, the fan is adjusted to operate at the maximum air speed to ensure that the refrigerant of the indoor unit is timely discharged, so that the safety of the multi-split air conditioning system is prevented from being affected, and if the indoor unit where the refrigerant leakage occurs is shut down, the fan is opened and adjusted to operate at the maximum air speed to ensure that the refrigerant of the indoor unit is timely discharged, so that the safety of the multi.
Drawings
Fig. 1 is a heating schematic diagram of a multi-split air conditioning system according to an embodiment of the present invention;
fig. 2 is a refrigeration schematic diagram of a multi-split air conditioning system according to an embodiment of the present invention;
fig. 3 is a flowchart of a control method of a multi-split air conditioning system of the present invention;
fig. 4 is a comparison table showing pipe diameter of a pipe section, compressor frequency and theoretical pressure drop per unit length of a multi-split air conditioning system according to the present invention.
Detailed Description
Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and are not intended to limit the scope of the present invention.
It should be noted that in the description of the present invention, the terms of direction or positional relationship indicated by the terms "middle", "upper", "lower", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, which are only for convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.
Furthermore, it should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
The invention provides a control method of a multi-split air conditioning system, aiming at carrying out omnibearing detection on pipelines of the whole multi-split air conditioning system so as to judge whether refrigerant leakage occurs, not only improving the detection accuracy, but also detecting the refrigerant leakage condition in real time without the detection lag condition, avoiding the influence on the operation of the multi-split air conditioning system, avoiding the influence on environmental protection and improving the operation safety of the multi-split air conditioning system.
Specifically, as shown in fig. 1 and 2, the multi-split air conditioning system of the present invention includes one outdoor unit 1, a plurality of indoor units 2 (shown in fig. 1 and 2 as having two indoor units 2), a compressor 3, the outdoor unit 1, the indoor units 2, the compressor 3 and the gas-liquid separator 4 form a closed-loop refrigerant circulation system, the four-way valve 5 can enable the multi-split air-conditioning system to be switched between a cooling mode and a heating mode, an indoor unit throttle valve 6 is arranged on one side of each indoor unit 2, the indoor unit throttle valves 6 are arranged on the downstream side of the indoor units 2 when the multi-split air-conditioning system is in the heating mode (namely corresponding to the upstream side of the indoor units 2 when the multi-split air-conditioning system is in the cooling mode), an outdoor unit throttle valve 7 is arranged on one side of the outdoor unit 1, and the outdoor unit throttle valve 7 is arranged on the upstream side of the outdoor unit 1 when the multi-split air-conditioning system is. A sensor for detecting a refrigerant pressure Psc is disposed at one side of the outdoor unit 1, and is configured to detect a liquid-phase pressure outside the outdoor unit when the multi-split air conditioning system performs cooling or heating operations, sensors for detecting an indoor-side liquid-phase refrigerant pressure P1 and an indoor-side gas-phase refrigerant pressure P2 are disposed at one side of each of the indoor units 2 (in the case of two indoor units 2 in fig. 1 and 2, the liquid-phase refrigerant pressure of one indoor unit 2 is P11, the gas-phase refrigerant pressure is P21, the liquid-phase refrigerant pressure of the other indoor unit 2 is P12, and the gas-phase refrigerant pressure is P22), a sensor for detecting an intake pressure Ps of the compressor 3 is disposed at an intake side of the compressor 3 (specifically disposed at an upstream side of the gas-liquid separator 4, i.e., between the four-way valve 5 and the gas-liquid separator 4), and a sensor for detecting an exhaust pressure. When the multi-split air conditioning system is in a refrigeration working condition, all the sections except a pipe section (Ps-Pd) of the compressor 3 are in a pressure rise section, and the rest sections are in a pressure drop section, specifically, a pressure drop pipe section (Pd-Psc) of the outdoor unit 1 and a pressure drop pipe section (P1-P2) of the indoor unit 2, in the case of two indoor units 2 in fig. 1 and 2, the pressure drop pipe sections of the two indoor units 2 are respectively P11-P21 and P12-P22, and the pressure drop pipe sections of the main pipe are respectively Psc-P1 and P2-Ps. When the multi-split air conditioning system is in a heating working condition, all the sections except the pipe section (Ps-Pd) of the compressor 3 are in a pressure rise section, and the rest sections are in a pressure drop section, specifically, the pressure drop pipe section (Psc-Ps) of the outdoor unit 1 and the pressure drop pipe section (P2-P1) of the indoor unit 2, in the case that two indoor units 2 are provided in fig. 1 and 2, the pressure drop pipe sections of the two indoor units 2 are respectively P21-P11 and P22-P12, and the pressure drop pipe sections of the main pipe are respectively P1-Psc and Pd-P2. In the present invention, the pressure drop of the indoor units 2 is collectively expressed by Δ PN (the pressure drops of the two indoor units 2 are collectively expressed by Δ PN1 and Δ PN 2), the pressure drop of the outdoor unit 1 is collectively expressed by Δ PW, and the pressure drop of the main pipe is collectively expressed by Δ PZ1 and Δ PZ2, respectively. In addition, in order to further distinguish the actual pressure drop and the theoretical pressure drop, if the actual pressure drop of the indoor unit 2, the actual pressure drop of the outdoor unit 1 and the actual pressure drop of the main pipeline are respectively added with letters "a", that is, the actual pressure drop Δ PAN of the indoor unit 2, the actual pressure drop Δ PAW of the outdoor unit 1 and the actual pressure drop of the main pipeline are respectively Δ PAZ1 and Δ PAZ2, and if the theoretical pressure drop of the indoor unit 2, the theoretical pressure drop Δ PSN of the outdoor unit 1 and the theoretical pressure drop of the main pipeline are respectively added with letters "S", that is, the theoretical pressure drop Δ PSN of the indoor unit 2, the theoretical pressure drop Δ PSW of the outdoor unit 1 and the theoretical pressure drop Δ PSZ1 and Δ PSZ 2.
Still taking the multi-split air conditioning system with two indoor units as an example, as shown in fig. 1 and 2, when the multi-split air conditioning system is in the cooling condition, the actual pressure drop Δ PAN1 of the indoor unit 1 is P11-P21, the actual pressure drop Δ PAN2 of the indoor unit 2 is P12-P22, the actual pressure drop Δ PAW of the outdoor unit is Pd-Psc, the actual pressure drop Δ PAZ1 of the main pipe is Psc-P1, and the actual pressure drop Δ PAZ2 is P2-Ps. When the multi-split air-conditioning system is in a heating working condition, the actual pressure drop delta PAN1 of the indoor unit 1 is P21-P11, the actual pressure drop delta PAN2 of the indoor unit 2 is P22-P12, the actual pressure drop delta PAW of the outdoor unit is Psc-Ps, the actual pressure drop delta PAZ1 of the main pipeline is P1-Psc, and the actual pressure drop delta PAZ2 is Pd-P2.
As shown in fig. 3, the control method of the present invention includes: acquiring the actual pressure drop of a main pipeline, the actual pressure drop of an outdoor unit and the actual pressure drop of each indoor unit; comparing the actual pressure drop of the main pipeline with the theoretical pressure drop of the main pipeline, comparing the actual pressure drop of the outdoor unit with the theoretical pressure drop of the outdoor unit, and comparing the actual pressure drop of each indoor unit with the respective theoretical pressure drop of each indoor unit; and if the actual pressure drop of the main pipeline is greater than the theoretical pressure drop of the main pipeline and lasts for a set time, or the actual pressure drop of the outdoor unit is greater than the theoretical pressure drop of the outdoor unit and lasts for a set time, or the actual pressure drop of any indoor unit is greater than the theoretical pressure drop of the indoor unit and lasts for a set time, judging that the refrigerant leakage of the multi-split air-conditioning system occurs. The set time may be T, that is, when Δ PAN >/Δ PSN and duration T of any indoor unit, or actual pressure drop Δ PAW >/Δ PSW and duration T of an outdoor unit, or Δ PAZ1 >/Δ PSZ1 and duration T of the main pipeline, or Δ PAZ2 >/Δ PSZ2 and duration T of the main pipeline, it may be determined that refrigerant leakage occurs in the multi-split air conditioning system. The duration T may be set according to the specification of the multi-split air conditioning system, for example, the duration T may be set to 0.5 hour or 1 hour.
Preferably, the theoretical pressure drop Δ PSN of each indoor unit can be determined according to the current operation mode of the multi-split air-conditioning system, the compressor frequency of the multi-split air-conditioning system, and the pipe diameter and the length of the pipe section of the indoor unit. The method specifically comprises the following steps: as shown in fig. 4, first, a theoretical pressure drop per unit length is determined according to an operation frequency of a compressor and a pipe diameter of a pipe section of an indoor unit (for example, in fig. 4, when a pipe diameter D is 13mm and an operation frequency F of the compressor is 120HZ, the theoretical pressure drop per unit length xm is 1.5kPa), and then the theoretical pressure drop per unit length is obtained by multiplying the pipe section length, if the multi-split air conditioning system is currently in a cooling mode, a sum of the obtained theoretical pressure drop per unit length of the pipe section and pressure losses of each component of the indoor unit is a theoretical pressure drop Δ PSN of the corresponding indoor unit, if the multi-split air conditioning system is currently in a heating mode, the obtained theoretical pressure drop per unit length of the pipe section is further multiplied by λ, and the sum of the obtained sum of the pressure losses of each component of the indoor unit is the theoretical pressure drop Δ PSN of, λ can be flexibly set according to the specification of the multi-split air conditioning system, for example, λ can be 0.65. It should be noted that the pipe diameter and the length of the pipe section of each indoor unit may not be exactly the same, so the theoretical pressure drop corresponding to each indoor unit is also calculated independently. In the actual comparison process, the actual pressure drop of one indoor unit is compared with the corresponding theoretical pressure drop of the indoor unit.
Preferably, similarly to the indoor unit, the theoretical pressure drop Δ PSW of the outdoor unit may be determined according to the current operation mode of the multi-split air conditioning system, the compressor frequency of the multi-split air conditioning system, and the pipe section diameter and length of the outdoor unit. The method specifically comprises the following steps: as shown in fig. 4, a theoretical pressure drop per unit length is determined according to an operation frequency of a compressor and a pipe section diameter (if the pipe section is a variable diameter pipe section, an average value of the pipe section diameter and the pipe section diameter is obtained) of the outdoor unit, and then the theoretical pressure drop per unit length is obtained by multiplying the pipe section length by the theoretical pressure drop per unit length, if the multi-split air conditioning system is currently in a cooling mode, a sum of the obtained theoretical pressure drop per unit length of the pipe section and pressure losses of the outdoor unit is a theoretical pressure drop Δ PSW of the corresponding outdoor unit, if the multi-split air conditioning system is currently in a heating mode, the obtained theoretical pressure drop per unit length of the pipe section is further multiplied by λ, and the sum of the obtained sum of the pressure losses of the pipe section and the pressure losses of the outdoor unit is the theoretical pressure.
Preferably, the theoretical pressure drop of the main pipe may be determined according to a current operation mode of the multi-split air conditioning system, a compressor frequency of the multi-split air conditioning system, the number of the indoor units, an installation position of the outdoor units, and a pipe diameter and a length of the main pipe. The method specifically comprises the following steps: when the multi-split air conditioning system is currently in a cooling mode: Δ PSZ1 is Lxm + Nm × 15 ± ρ ghm, where L is the length of the pipe between the sensor for detecting Psc and the sensor for detecting P1, xm is the theoretical pressure drop per unit length, which can be specifically determined by the table in fig. 4 (i.e., determined by the pipe diameter and the frequency of the compressor), Nm is the total number of the collecting pipes and the branch pipes between the outdoor unit and the mth indoor unit, which can be determined according to the number of the indoor units, for example, when the number of the indoor units is 4, for the 1 st indoor unit, the number of the collecting pipes and the branch pipes on the main pipe is 0+1 to 1, and similarly, for the 2 nd indoor unit and the 3 rd indoor unit, the number of the collecting pipes and the branch pipes on the main pipe is 0+2 to 2 and the number of the branch pipes on the main pipe is 0+3 to 3, respectively; it should be noted that the last indoor unit, i.e., the 4 th indoor unit and the 3 rd indoor unit, share one manifold, so the number of manifolds and manifolds on the corresponding pipelines of the 4 th indoor unit is 0+3, hm is the height difference between the mth indoor unit and the outdoor unit, when the outdoor unit is located below the indoor unit, "+/-" in the formula is taken "+", and when the outdoor unit is located above the indoor unit, "+/-" in the formula is taken "-"; Δ PSZ2 is Lxm + Nm × 15 ± ρ ghm, where L is the length of a pipe segment between a sensor for detecting P2 and a sensor for detecting Ps, xm is a theoretical pressure drop per unit length, which can be specifically determined by the table in fig. 4 (i.e., determined by the pipe segment pipe diameter and the frequency of the compressor), Nm is the total number of the collecting pipes and the branch pipes between the outdoor unit and the mth indoor unit, which can be determined according to the number of the indoor units, for example, when the number of the indoor units is 4, for the 1 st indoor unit, the number of the collecting pipes and the branch pipes on the main pipe is 0+1 to 1, and similarly, for the 2 nd indoor unit and the 3 rd indoor unit, the number of the collecting pipes and the branch pipes on the main pipe is 0+2 to 2 and the number of the branch pipes on the main pipe is 0+3 to 3, respectively; it should be noted that the last indoor unit, i.e., the 4 th indoor unit and the 3 rd indoor unit, share one branch pipe, so the number of the collecting pipes and the branch pipes on the corresponding pipelines of the 4 th indoor unit is 0+3 to 3, hm is the height difference between the mth indoor unit and the outdoor unit, when the outdoor unit is located below the indoor unit, "+/-" is taken in the formula, and when the outdoor unit is located above the indoor unit, "+/-" is taken in the formula. When the multi-split air conditioning system is currently in a heating mode: Δ PSZ1 ═ λ Lxm + Nm × 15 ± ρ ghm, where λ is a correction value, L is a length of a pipe section between a sensor for detecting P1 and a sensor for detecting Psc, xm is a theoretical pressure drop per unit length, which can be specifically determined by the table of fig. 4 (i.e., determined by a pipe section pipe diameter and a frequency of a compressor), Nm is a total number of collecting pipes and branching pipes between the outdoor unit and the mth indoor unit, which can be determined according to the number of indoor units, for example, when the number of indoor units is 4, for the 1 st indoor unit, the number of collecting pipes and branching pipes on the main pipe is 0+1 to 1, and similarly, for the 2 nd and 3 th indoor units, the number of collecting pipes and branching pipes on the main pipe is 0+2 to 2 and the number of branching pipes on the main pipe is 0+3 to 3, respectively; it should be noted that the last indoor unit, i.e., the 4 th indoor unit and the 3 rd indoor unit, share one manifold, so the number of manifolds and manifolds on the corresponding pipelines of the 4 th indoor unit is 0+3, hm is the height difference between the mth indoor unit and the outdoor unit, when the outdoor unit is located below the indoor unit, "+/-" takes "-" in the formula, and when the outdoor unit is located above the indoor unit, "+/-" takes "+" in the formula; Δ PSZ2 ═ λ Lxm + Nm × 15 ± ρ ghm, where λ is a correction value, L is a length of a pipe section between a sensor for detecting Pd and a sensor for detecting P2, xm is a theoretical pressure drop per unit length, which can be specifically determined by the table of fig. 4 (i.e., determined by a pipe section diameter and a frequency of a compressor), Nm is a total number of collecting pipes and branching pipes between the outdoor unit and the mth indoor unit, which can be determined according to the number of indoor units, for example, when the number of indoor units is 4, for the 1 st indoor unit, the number of collecting pipes and branching pipes on the main pipe is 0+1 to 1, and similarly, for the 2 nd and 3 rd indoor units, the number of collecting pipes and branching pipes on the main pipe is 0+2 to 2 and the number of 0+3 to 3, respectively; it should be noted that the last indoor unit, i.e., the 4 th indoor unit and the 3 rd indoor unit, share one branch pipe, so the number of the collecting pipes and the branch pipes on the corresponding pipelines of the 4 th indoor unit is 0+3 to 3, hm is the height difference between the mth indoor unit and the outdoor unit, when the outdoor unit is located below the indoor unit, "+/-" in the formula is taken as "+", and when the outdoor unit is located above the indoor unit, "+/-" in the formula is taken as "-".
It should be noted that the above theoretical pressure drop of the indoor unit, the theoretical pressure drop of the outdoor unit, and the theoretical pressure drop of the main pipe are only preferred calculation methods, and those skilled in the art may also use other methods to calculate the theoretical pressure drop of the indoor unit, the theoretical pressure drop of the outdoor unit, and the theoretical pressure drop of the main pipe.
Preferably, with reference to fig. 3, after the step of determining refrigerant leakage of the multi-split air conditioning system, the control method of the present invention further includes: further determining the position of refrigerant leakage; and executing corresponding control operation according to the determination result. As described above, it is determined that refrigerant leakage occurs in any indoor unit when Δ PAN >. DELTA.psn continues for a time T, in the outdoor unit when actual pressure drop Δ PAW >. DELTA.psw continues for a time T, and in the main pipe when Δ PAZ1 >. DELTA.psz 1 continues for a time T or in the main pipe when Δ PAZ2 >. DELTA.psz 2 continues for a time T. It should be noted that the leakage positions may occur simultaneously, that is, the indoor unit and the outdoor unit may leak simultaneously, the outdoor unit and the main pipe may also leak simultaneously, and the determination of whether the respective pipe sections leak is independent of each other and is not affected, so that the whole pipe system of the multi-split air conditioning system can be detected in real time. In one possible case, the step of "performing the corresponding control operation according to the determination result" includes: and if the position where the refrigerant leakage occurs comprises an outdoor unit or a main pipeline, stopping the whole multi-split air conditioning system. That is, if the outdoor unit or the main pipe leaks refrigerant, it is indicated that the operation of the whole multi-split air conditioning system is resumed and the multi-split air conditioning system is stopped. Meanwhile or later, the multi-split air conditioning system gives an alarm and displays a specific leakage interval, and then maintenance personnel can conveniently and quickly maintain the leakage position, so that the maintenance efficiency is improved. In another possible case, the step of "performing the corresponding control operation according to the determination result" includes: if the position where the refrigerant leakage occurs only comprises one or more indoor units, judging whether the indoor unit with the refrigerant leakage is started or not; if the indoor unit with the refrigerant leakage is started, closing a valve group of the indoor unit with the refrigerant leakage and adjusting a fan of the indoor unit to the maximum air speed for operation; and if the indoor unit with the refrigerant leakage is shut down, starting a fan of the indoor unit with the refrigerant leakage and adjusting the fan to the maximum air speed for operation. That is, if only one or more indoor units have refrigerant leakage, but neither the main pipe nor the outdoor unit has refrigerant leakage, the indoor unit without refrigerant leakage can still normally operate, at this time, whether the indoor unit with refrigerant leakage is started up can be judged, if the indoor unit is started up, the valve bank is closed, namely, the throttle valve and the electromagnetic valve of the indoor unit are closed, large-area leakage caused by further refrigerant flowing into the indoor unit is avoided, the fan of the indoor unit is adjusted to the maximum air speed for operation to form air convection, the flowing refrigerant is ensured to be blown away quickly, the occurrence of flammability or explosion caused by overhigh local concentration is avoided, the safety of the multi-split air conditioning system is improved, if the fan bank is closed, the valve bank is closed, and in the same way, the fan of the indoor unit is opened and adjusted to the maximum air speed for operation to form air convection, the flowing refrigerant is ensured to be blown away quickly, the phenomenon that the refrigerant is combustible or explosive due to overhigh local concentration is avoided, and the safety of the multi-split air-conditioning system is improved. In addition, no matter the indoor unit with refrigerant leakage is started or shut down, the multi-split air conditioning system alarms and displays a specific leakage interval while or after executing corresponding control operation, and then maintenance personnel can conveniently and quickly maintain the indoor unit with refrigerant leakage, so that the maintenance efficiency is improved.
So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.

Claims (10)

1. A control method of a multi-split air conditioning system is characterized in that the multi-split air conditioning system comprises an outdoor unit and a plurality of indoor units, the indoor units are connected with the outdoor unit through main pipelines, and the control method comprises the following steps:
acquiring the actual pressure drop of the main pipeline, the actual pressure drop of the outdoor unit and the actual pressure drop of each indoor unit;
comparing the actual pressure drop of the main pipeline with the theoretical pressure drop of the main pipeline, comparing the actual pressure drop of the outdoor unit with the theoretical pressure drop of the outdoor unit, and comparing the actual pressure drop of each indoor unit with the respective theoretical pressure drop of each indoor unit;
and if the actual pressure drop of the main pipeline is greater than the theoretical pressure drop of the main pipeline and lasts for a set time, or the actual pressure drop of the outdoor unit is greater than the theoretical pressure drop of the outdoor unit and lasts for the set time, or the actual pressure drop of any indoor unit is greater than the theoretical pressure drop of the indoor unit and lasts for the set time, judging that the refrigerant leakage of the multi-split air-conditioning system occurs.
2. The control method as set forth in claim 1, wherein after the step of determining that refrigerant leakage occurs in the multi-split air conditioning system, the control method further comprises:
further determining the position of refrigerant leakage;
and executing corresponding control operation according to the determination result.
3. The control method according to claim 2, wherein the step of "performing the corresponding control operation according to the determination result" includes:
and if the position where the refrigerant leakage occurs comprises the outdoor unit or the main pipeline, stopping the whole multi-split air-conditioning system.
4. The control method as set forth in claim 3, wherein, simultaneously with or after the step of "shutting down the whole of the multi-split air conditioning system", the control method further comprises:
and alarming and displaying the leakage interval.
5. The control method according to claim 2, wherein the step of "performing the corresponding control operation according to the determination result" includes:
if the position where the refrigerant leakage occurs only comprises one or more indoor units, judging whether the indoor unit with the refrigerant leakage is started or not;
if the indoor unit with the refrigerant leakage is started, closing a valve group of the indoor unit with the refrigerant leakage and adjusting a fan of the indoor unit to the maximum air speed for operation;
and if the indoor unit with the refrigerant leakage is shut down, starting a fan of the indoor unit with the refrigerant leakage and adjusting the fan to the maximum air speed for operation.
6. The control method according to claim 5, wherein, simultaneously with or after the step of closing a valve group of an indoor unit in which refrigerant leakage occurs and adjusting a fan of the indoor unit to a maximum wind speed operation, the control method further comprises:
and alarming and displaying the leakage interval.
7. The control method according to claim 5, wherein, simultaneously with or after the step of turning on a fan of the indoor unit in which refrigerant leakage occurs and adjusting to a maximum air speed operation, the control method further comprises:
and alarming and displaying the leakage interval.
8. The control method as claimed in any one of claims 1 to 7, wherein the theoretical pressure drop of the main pipe is determined according to a current operation mode of the multi-split air conditioning system, a compressor frequency of the multi-split air conditioning system, the number of indoor units, an installation position of the outdoor unit, a pipe diameter and a length of the main pipe.
9. The control method as claimed in any one of claims 1 to 7, wherein the theoretical pressure drop of the outdoor unit is determined according to a current operation mode of the multi-split air conditioning system, a compressor frequency of the multi-split air conditioning system, a pipe section diameter and a length of the outdoor unit.
10. The control method as claimed in any one of claims 1 to 7, wherein the theoretical pressure drop of each indoor unit is determined according to the current operation mode of the multi-split air-conditioning system, the compressor frequency of the multi-split air-conditioning system, and the pipe section diameter and length of the indoor unit.
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