CN113266929A - Multi-split air conditioner and control method thereof - Google Patents
Multi-split air conditioner and control method thereof Download PDFInfo
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- CN113266929A CN113266929A CN202110551230.7A CN202110551230A CN113266929A CN 113266929 A CN113266929 A CN 113266929A CN 202110551230 A CN202110551230 A CN 202110551230A CN 113266929 A CN113266929 A CN 113266929A
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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
- F24F11/50—Control or safety arrangements characterised by user interfaces or communication
- F24F11/54—Control or safety arrangements characterised by user interfaces or communication using one central controller connected to several sub-controllers
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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
- F24F11/50—Control or safety arrangements characterised by user interfaces or communication
- F24F11/61—Control or safety arrangements characterised by user interfaces or communication using timers
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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
- F24F11/70—Control systems characterised by their outputs; Constructional details thereof
- F24F11/80—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air
- F24F11/83—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers
- F24F11/84—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers using valves
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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
- F24F11/70—Control systems characterised by their outputs; Constructional details thereof
- F24F11/80—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air
- F24F11/87—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling absorption or discharge of heat in outdoor units
- F24F11/871—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling absorption or discharge of heat in outdoor units by controlling outdoor fans
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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
- F24F2110/00—Control inputs relating to air properties
- F24F2110/10—Temperature
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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
- F24F2140/00—Control inputs relating to system states
- F24F2140/20—Heat-exchange fluid temperature
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Abstract
The invention discloses a multi-split air conditioner and a control method thereof, and the multi-split air conditioner comprises: the refrigerant self-charging control system comprises a plurality of indoor units, an outdoor unit, a controller and a refrigeration cycle loop for connecting the indoor units and the outdoor unit, wherein in the self-charging process of the refrigerant, the controller controls the average density of the refrigerant in the refrigeration cycle loop based on a predetermined control target; and calculating to complete the self-filling of the refrigerant according to the real-time operation parameters of the refrigeration cycle loop and the real-time parameters of the outdoor environment. The invention realizes the accurate filling of the refrigerant quantity in the updating process of the multi-split air conditioner, solves the problem that the comfort and the reliability of the multi-split air conditioner are influenced because the refrigerant cannot be accurately added in the updating process of the multi-split air conditioner, improves the comfort and the reliability of the multi-split air conditioner, and further improves the experience of customers.
Description
Technical Field
The invention relates to the technical field of multi-split air conditioners, in particular to a multi-split air conditioner and a control method thereof.
Background
With the development of the multi-split air conditioner market, the multi-split air conditioner has entered the multi-split updating era, in order to not damage the overall structure of the building and reduce the construction difficulty, the multi-split air conditioner only needs to update the outdoor unit in the updating process, the indoor unit, the connecting liquid pipe, the connecting gas pipe and the like do not need to be replaced, and a certain amount of refrigerant needs to be filled into the multi-split air conditioner after the multi-split air conditioner is updated.
At present, in the process of updating the multi-split air conditioner, under the condition that an indoor unit, a connecting liquid pipe, a connecting air pipe and the like are not clear, the refrigerant is difficult to be accurately added into the multi-split air conditioner, and if the adding amount of the refrigerant is inaccurate, the comfort and the reliability of the multi-split air conditioner are influenced in the operation process of the multi-split air conditioner, and the customer experience is poor.
Disclosure of Invention
The invention provides a multi-split air conditioner and a control method thereof, aiming at solving the problems that in the prior art, a refrigerant cannot be accurately added in the updating process of the multi-split air conditioner, and the comfort and the reliability of the multi-split air conditioner are influenced.
In a first aspect, an embodiment of the present invention provides a multi-split air conditioner, including a plurality of indoor units, an outdoor unit, a controller, and a refrigeration cycle circuit for connecting the plurality of indoor units and the outdoor unit, wherein the controller is configured to:
controlling the average density of the refrigerant in the refrigeration cycle circuit based on a predetermined control target during self-charging of the refrigerant;
and calculating to complete the self-filling of the refrigerant according to the real-time operation parameters of the refrigeration cycle loop and the real-time parameters of the outdoor environment.
In some of these embodiments, the refrigeration cycle includes: the air-liquid separator, the compressor, the outdoor heat exchanger, the outdoor electronic expansion valve, the bypass electronic expansion valve, the indoor electronic expansion valves and the indoor heat exchangers are connected through the connecting liquid pipe and the connecting air pipe, and the outdoor heat exchanger is provided with the outdoor fan.
In some of these embodiments, the controller is further configured to:
in the self-charging process of the refrigerant, controlling a plurality of indoor units to perform refrigeration operation at a preset air volume, and controlling the opening degree of an outdoor electronic expansion valve to be the maximum value;
controlling the plurality of indoor electronic expansion valves, the plurality of indoor heat exchangers, the outdoor heat exchanger, the gas-liquid separator, the compressor, the outdoor fan and the bypass electronic expansion valve to operate at a control target based on the control target, thereby controlling the average density of the refrigerant in the refrigeration cycle circuit;
and calculating to complete the self-filling of the refrigerant according to the real-time operation parameters of the compressor, the real-time operation parameters of the outdoor heat exchanger and the real-time parameters of the outdoor environment.
In some of these embodiments, the controller is further configured to:
according to the real-time operation parameters of the compressor and the real-time parameters of the outdoor environment, when the first preset functional relation is met, the frequency of the compressor and the rotating speed of the outdoor fan are controlled to be kept unchanged;
and according to the real-time operation parameters of the outdoor heat exchanger and the real-time parameters of the outdoor environment, calculating to control to finish the self-charging of the refrigerant when the second preset functional relation is met.
In some of these embodiments, the controller is further configured to:
the refrigerant dryness control method comprises the steps of calculating refrigerant dryness of a plurality of indoor heat exchangers, controlling the plurality of indoor heat exchangers to operate according to an evaporation pressure control target based on a predetermined refrigerant dryness control target and an evaporation pressure control target, and controlling the opening degree of a plurality of indoor electronic expansion valves to adjust the refrigerant dryness of the plurality of indoor heat exchangers so that the refrigerant dryness meets the refrigerant dryness control target, thereby controlling the average density of refrigerant in the plurality of indoor heat exchangers, wherein the refrigerant dryness control target is more than 0.3, and the evaporation pressure control target is 0.6-0.9 MPa.
In some of these embodiments, the controller is further configured to:
based on the evaporation pressure control target, the compressor is controlled to operate with the evaporation pressure control target as a suction pressure, thereby controlling the average density of the refrigerant in the compressor.
In some of these embodiments, the controller is further configured to:
and controlling the opening degrees of the indoor electronic expansion valves to adjust the superheat degrees of the indoor heat exchangers based on an evaporation pressure control target and a predetermined superheat degree control target, so that the superheat degrees meet the superheat degree control target, thereby controlling the average density of the refrigerant in the connecting gas pipe and the gas-liquid separator, wherein the superheat degree control target is more than 10 ℃.
In some of these embodiments, the controller is further configured to:
and controlling the outdoor heat exchanger and the outdoor fan to respectively operate at the condensation pressure control target based on the predetermined condensation pressure control target, so as to control the average density of the refrigerant in the outdoor heat exchanger, wherein the condensation pressure control target is 2.3-3.0 MPa.
In some of these embodiments, the controller is further configured to:
and controlling the opening degree of the bypass electronic expansion valve to adjust the supercooling degree of the outdoor heat exchanger based on the predetermined supercooling degree control target and the condensation pressure control target, so that the supercooling degree meets the supercooling degree control target, the average density of the refrigerant in the connecting liquid pipe is controlled, and the supercooling degree control target is more than 15 ℃.
In some of these embodiments, the outdoor heat exchanger comprises: the first outdoor heat exchanger, the second outdoor heat exchanger and the third outdoor heat exchanger are sequentially arranged along the vertical direction;
the top of the first outdoor heat exchanger is provided with an outdoor fan, and the first outdoor heat exchanger is communicated with the compressor through a connecting liquid pipe;
the second outdoor heat exchanger is communicated with the compressor through a connecting liquid pipe and is also connected with the first outdoor heat exchanger in parallel;
the third outdoor heat exchanger is communicated with the indoor heat exchangers through the connecting liquid pipes, and the third outdoor heat exchanger is connected with the first outdoor heat exchanger in series and is also connected with the second outdoor heat exchanger in series.
In some of these embodiments, the outdoor heat exchanger comprises: the first outdoor heat exchanger, the second outdoor heat exchanger, the third outdoor heat exchanger and the fourth outdoor heat exchanger are sequentially arranged along the vertical direction;
the outdoor fan includes: the first outdoor fan is arranged on the same side of the first outdoor heat exchanger and the second outdoor heat exchanger, and the second outdoor fan is arranged on the same side of the third outdoor heat exchanger and the fourth outdoor heat exchanger;
the first outdoor heat exchanger is communicated with the compressor through a connecting liquid pipe and is also connected with the second outdoor heat exchanger in series;
the fourth outdoor heat exchanger is communicated with the compressor through a connecting liquid pipe and is also connected with the third outdoor heat exchanger in series;
the second outdoor heat exchanger and the third outdoor heat exchanger are connected in parallel, and parallel branches of the second outdoor heat exchanger and the third outdoor heat exchanger are communicated with the plurality of indoor heat exchangers.
In a second aspect, an embodiment of the present invention provides a control method of a multi-split air conditioner, applied to the multi-split air conditioner as described above, including:
controlling the average density of the refrigerant in the refrigeration cycle circuit based on a predetermined control target during self-charging of the refrigerant;
and calculating to complete the self-filling of the refrigerant according to the real-time operation parameters of the refrigeration cycle loop and the real-time parameters of the outdoor environment.
The invention has the technical effects or advantages that:
according to the multi-split air conditioner and the control method thereof provided by the embodiment of the invention, the average density of the refrigerant in the refrigeration cycle loop is controlled based on the predetermined control target, so that the accurate filling of the refrigerant quantity in the updating process of the multi-split air conditioner is realized, the problem that the comfort and the reliability of the multi-split air conditioner are influenced due to the fact that the refrigerant cannot be accurately added in the updating process of the multi-split air conditioner is solved, the comfort and the reliability of the multi-split air conditioner are improved, and the experience of a client is further improved.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention.
Fig. 1 is a schematic structural diagram of a multi-split air conditioner according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a refrigeration cycle circuit according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a refrigerant self-charging cycle provided by an embodiment of the present invention;
FIG. 4 is a schematic diagram of the refrigerant distribution in the refrigeration cycle according to the embodiment of the present invention;
FIG. 5 is a graph of density versus dryness for two-phase refrigerant at various vapor pressures provided by embodiments of the present invention;
FIG. 6 is a graph of density difference versus dryness for two-phase refrigerants at different vapor pressures as provided by embodiments of the present invention;
FIG. 7 is a graph of superheated refrigerant density versus superheat at various evaporating pressures as provided by an embodiment of the present invention;
FIG. 8 is a graph of superheated refrigerant density versus superheat at various condensing pressures as provided by an embodiment of the present invention;
FIG. 9 is a graph of density versus dryness for two-phase refrigerant at different condensing pressures provided by embodiments of the present invention;
FIG. 10 is a graph of the average density of two-phase refrigerant at different condensing pressures provided by embodiments of the present invention;
FIG. 11 is a graph of average density of liquid refrigerant versus subcooling for different condensing pressures as provided by an embodiment of the present invention;
FIG. 12 is a graph of compressor discharge pressure versus outdoor ambient temperature provided by embodiments of the present invention;
FIG. 13 is a graph of the degree of subcooling of an outdoor heat exchanger versus the temperature of the outdoor environment in accordance with embodiments of the present invention;
FIG. 14 is a graph of the error between the refrigerant self-charge and the target refrigerant quantity provided by the embodiment of the present invention;
FIG. 15 is a diagram of yet another refrigerant self-charging cycle provided by an embodiment of the present invention;
fig. 16 is a schematic structural view of still another refrigeration cycle circuit provided in the embodiment of the present invention;
fig. 17 is a distribution diagram of a multi-split top-out fan type outdoor wind field according to an embodiment of the present invention;
fig. 18 is a schematic structural view of still another refrigeration cycle circuit provided in the embodiment of the present invention;
fig. 19 is a distribution diagram of a multi-connected dual-fan side-outlet fan type outdoor wind field according to an embodiment of the present invention;
FIG. 20 is a flowchart illustrating a method for controlling a multi-split air conditioner according to an embodiment of the present invention;
in the above figures:
1. a controller; 2. an indoor unit; 3. an outdoor unit;
4. a refrigeration cycle loop; 401. a connecting liquid pipe; 402. connecting an air pipe; 403. a gas-liquid separator; 404. a compressor; 405. an oil separator; 406. an outdoor heat exchanger; 4061. a first outdoor heat exchanger; 4062. a second outdoor heat exchanger; 4063. a third outdoor heat exchanger; 4064. a fourth outdoor heat exchanger; 407. an outdoor electronic expansion valve; 408. bypassing the electronic expansion valve; 409. a supercooling heat exchanger; 410. an indoor electronic expansion valve; 411. an indoor heat exchanger; 412. a heat regenerator; 413. an outdoor fan; 4131. a first outdoor fan; 4132. a second outdoor fan; 414. a liquid side stop valve; 415. a gas side stop valve; 416. refrigerant self-charging electromagnetic valve; 417. a first capillary tube; 418. the refrigerant self-charging electronic expansion valve; 419. a second capillary tube; 420. an exhaust gas temperature sensor; 421. an exhaust pressure sensor; 422. an outdoor temperature sensor; 423. an outdoor liquid pipe temperature sensor; 424. a temperature sensor at the liquid side stop valve; 425. a pressure sensor at the liquid side stop valve; 426. an indoor liquid pipe temperature sensor; 427. a mid-position temperature sensor; 428. an indoor air pipe temperature sensor; 429. a four-way valve;
5. a refrigerant charge tank; 6. and a stop valve.
Detailed Description
In order to make the technical solutions of the present invention better understood by those skilled in the art, the present invention will be further described in detail with reference to the accompanying drawings and the detailed description. Although embodiments of the invention are disclosed in the accompanying drawings, it should be understood that the invention can be embodied in any form and should not be construed as limited to the embodiments set forth herein.
In the description of the present application, it is to be understood that reference to "a plurality" in the present application means two or more. "and/or" describes an association relationship of associated objects, meaning that three relationships may exist, for example, "A and/or B" may mean: a exists alone, A and B exist simultaneously, and B exists alone. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship. In the description of the present application, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a particular orientation, be constructed in a particular orientation, and be operated, and thus should not be construed as limiting the present application. Reference herein to the terms "first," "second," "third," and the like, are merely to distinguish similar objects and do not denote a particular ordering for the objects.
[ basic operation principle of air conditioner ]
The refrigeration cycle of the air conditioner includes a compressor, a condenser, a throttle valve, and an evaporator. The refrigeration cycle includes a series of processes involving compression, condensation, throttling, and evaporation, and supplies refrigerant to the air that has been conditioned and heat exchanged.
The compressor compresses a refrigerant gas in a high-temperature and high-pressure state and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant into a liquid phase, and heat is released to the surrounding environment through the condensation process.
The throttle valve throttles the liquid-phase refrigerant in a high-temperature and high-pressure state condensed in the condenser into a low-pressure liquid-phase refrigerant. The evaporator evaporates the refrigerant throttled in the throttle valve and returns the refrigerant gas in a low-temperature and low-pressure state to the compressor. The evaporator can achieve a cooling effect by heat-exchanging with a material to be cooled using latent heat of evaporation of a refrigerant. The air conditioner can adjust the temperature of the indoor space throughout the cycle.
The outdoor unit of an air conditioner refers to a portion including a compressor of a refrigeration cycle and includes an outdoor heat exchanger, the indoor unit of an air conditioner includes an indoor heat exchanger, and an electronic expansion valve may be provided in the indoor unit or the outdoor unit of an air conditioner.
The indoor heat exchanger and the outdoor heat exchanger serve as a condenser or an evaporator. When the indoor heat exchanger is used as a condenser, the air conditioner is used for heating in a heating mode, and when the indoor heat exchanger is used as an evaporator, the air conditioner is used for cooling in a cooling operation mode.
Example one
The multi-split air conditioner provided by the embodiment is suitable for all types of multi-split air conditioners, including a multi-split air conditioner ejector fan type and a multi-split air conditioner side outlet fan type. The refrigerant in the first embodiment may be R410 refrigerant, R32 refrigerant, or the like, and the type of the refrigerant is not particularly limited in the first embodiment. The first embodiment will explain how to accurately charge the R410 refrigerant by taking a multi-split top-out fan type and the R410 refrigerant as examples. Referring to fig. 1, the multi-split air conditioner includes a plurality of indoor units 2 (the number of the indoor units 2 is two or more), an outdoor unit 3, a controller 1, and a refrigeration cycle circuit 4 for connecting the plurality of indoor units 2 and the outdoor unit 3. The compression, condensation, throttling and evaporation are realized based on the refrigeration cycle circuit 4, referring to fig. 2, the arrow direction in fig. 2 represents the flow direction of the R410 refrigerant, the refrigerant cycle circuit 4 comprises a plurality of connection liquid pipes 401, a connection gas pipe 402, a gas-liquid separator 403, a compressor 404, an oil separator 405, an outdoor heat exchanger 406, an outdoor electronic expansion valve 407, a bypass electronic expansion valve 408, an indoor electronic expansion valve 410 and an indoor heat exchanger 411, wherein the outdoor fan 413 is arranged on the outdoor heat exchanger 406, and specifically, the outdoor fan 413 is arranged on the top of the outdoor heat exchanger 406.
The refrigeration cycle circuit 4 further includes: a four-way valve 429, a supercooling heat exchanger 409, a regenerator 412, a liquid side stop valve 414, a gas side stop valve 415, a refrigerant self-filling solenoid valve 416, a first capillary tube 417, a second capillary tube 419, a discharge air temperature sensor 420, a discharge air pressure sensor 421, an outdoor temperature sensor 422, an outdoor liquid pipe temperature sensor 423, a liquid side stop valve temperature sensor 424, a liquid side stop valve pressure sensor 425, an indoor liquid pipe temperature sensor 426, an intermediate position temperature sensor 427, and an indoor air pipe temperature sensor 428.
The high-temperature and high-pressure gaseous refrigerant discharged by the compressor 404 flows into the outdoor heat exchanger 406 through the oil separator 405, the outdoor heat exchanger 406 condenses the high-temperature and high-pressure gaseous refrigerant into a high-temperature and high-pressure supercooled liquid refrigerant, and heat is released to the surrounding environment through the condensation process.
A part of the high-temperature high-pressure subcooled liquid refrigerant is throttled into medium-pressure or low-pressure subcooled liquid refrigerant or two-phase refrigerant through the outdoor electronic expansion valve 407 and the bypass electronic expansion valve 408, and flows into an auxiliary circuit of the subcooling heat exchanger 409 to be further superheated; the other part of the refrigerant flows into the main path of the supercooling heat exchanger 409 through the outdoor electronic expansion valve 407, is further supercooled, and the high-temperature and high-pressure supercooled refrigerant flowing out of the main path flows into the indoor electronic expansion valve 410 through the liquid side stop valve 414.
The indoor electronic expansion valve 410 throttles the high-temperature high-pressure supercooled refrigerant into a low-temperature low-pressure two-phase refrigerant, the two-phase refrigerant is evaporated into a low-temperature low-pressure superheated refrigerant through the indoor heat exchanger 411, the low-temperature low-pressure superheated refrigerant passes through the gas side stop valve 415 and is merged with the low-temperature low-pressure superheated refrigerant flowing out from the auxiliary circuit, the low-temperature low-pressure superheated refrigerant flows into the inlet of the gas-liquid separator 403, the low-temperature low-pressure superheated refrigerant flows out from the outlet of the gas-liquid separator 403 and flows into the air suction port of the compressor 404, and the refrigeration operation mode is completed.
The four-way valve 429 is provided with four ports connected to outlets of the air-side shutoff valve 415, the outdoor heat exchanger 406, the gas-liquid separator 403, and the oil separator 405, respectively, to control the flow direction of the refrigerant.
Referring to fig. 3, the direction of the arrow is the flow direction of the refrigerant R410, when the refrigerant is self-filled, the refrigerant filling tank 5 and the outdoor unit 3 are connected through the stop valve 6, the multi-split air conditioner enters the refrigerant self-filling process, the stop valve 6 and the refrigerant self-filling electromagnetic valve 416 are opened, the refrigerant flowing out of the refrigerant filling tank 5 exchanges heat with the refrigerant flowing out of the oil separator 405 in the heat regenerator 412 through the stop valve 6, the refrigerant self-filling electromagnetic valve 416 and the first capillary tube 417, and it is further ensured that the refrigerant flowing into the gas-liquid separator 403 from the refrigerant filling tank 5 is in an overheated state, wherein the first capillary tube 417 prevents the refrigerant from being sucked into the refrigerant filling tank 5 excessively, and prevents the liquid from returning to the compressor 404.
Referring to fig. 4, the direction of the arrow is R410 refrigerant flow, and the refrigeration cycle circuit 4 is divided into a plurality of components according to the distribution of the refrigerant in the refrigeration cycle circuit 4, which are: a compressor 404 (including an oil separator 405) section, an outdoor heat exchanger 406 section, a connecting liquid pipe 401 section (including a main connecting liquid pipe and branch connecting liquid pipes), namely, the liquid side stop valve 414, the liquid pipe 401 connecting each indoor electronic expansion valve 410, the indoor heat exchanger 411 part, the connecting gas pipe 402 part (including the main connecting gas pipe and each branch connecting gas pipe), namely, the portion of each indoor heat exchanger 411 connected to the gas-side cut-off valve 415 with the gas pipe 402 and the gas-liquid separator 403, the other parts (including the part of the liquid pipe 401 connecting the outlet of the outdoor heat exchanger 406 to the liquid side stop valve 414, the part of the supercooling heat exchanger 409, the part of the gas pipe 402 connecting the outlet of the auxiliary passage of the supercooling heat exchanger 409 to the inlet of the gas-liquid separator 403, the part of the gas pipe 402 connecting the gas side stop valve 415 to the inlet of the gas-liquid separator 403, and the like) can be omitted because of the small volume, and the mass distribution of each component in the refrigeration cycle circuit 4 is calculated as follows:
mr_com＝ρr_com×Vcom (1)
in the above formula, mr_comExpressed as the amount of refrigerant in the compressor section; rhor_comExpressed as the average density of the refrigerant in the compressor section; vcomExpressed as the volume of the compressor and oil separator.
mr_c＝ρr_c×Vc (2)
In the above formula, mr_cExpressed as the amount of refrigerant in the outdoor heat exchanger section; rhor_cExpressed as the average density of refrigerant in the outdoor heat exchanger section; vcRepresented as the volume of the outdoor heat exchanger section.
In the above formula, mr_liquidExpressed as the amount of refrigerant in the connecting liquid pipe portion; m isr_LExpressed as the amount of refrigerant in the main connecting liquid pipe; m isr_LiExpressed as the amount of refrigerant in each branch connector; rhor_LExpressed as the average density in the main connecting-tube refrigerant; vLExpressed as the volume of the main connecting liquid pipe; rhor_LiExpressed as the average density in each branch connecting-tube refrigerant; vLiExpressed as the volume of each branch connecting liquid pipe; n represents the number of branch connector tubes.
In the above formula, mr_eExpressed as the amount of refrigerant in the indoor heat exchanger section; rhor_eiExpressed as the average density of refrigerant in each indoor heat exchanger; veiExpressed as the volume of each indoor heat exchanger; k is the number of indoor heat exchangers, and k is n.
In the above formula, mr_gasExpressed as the amount of refrigerant in the connecting air duct portion; m isr_gExpressed as the amount of refrigerant in the main connecting gas line; m isr_giExpressed as the amount of refrigerant in each branch connecting air pipe; rhor_gExpressed as the average density of refrigerant in the main connecting gas line; vgExpressed as the volume of the main connecting trachea; rhor_giExpressed as the average density of refrigerant in each branch connecting gas pipe; vgiExpressed as the volume of each branch connecting the trachea; z represents the number of branch connecting trachea, and z is equal to k is equal to n.
mr_acc＝ρr_acc×Vacc (6)
In the above formula, mr_accExpressed as the amount of refrigerant in the vapor-liquid separator portion; rhor_accExpressed as the average refrigerant density in the gas-liquid separator section; vaccExpressed as the volume of the gas-liquid separator portion.
According to the formulas (1) to (6), the volumes of all the components are constant, and the accuracy of the refrigerant self-charging amount under different conditions can be controlled by controlling the average refrigerant density of all the components. In the updating process of the multi-split air conditioner, the controller 1 in the multi-split air conditioner realizes the accurate filling of the refrigerant, which is as follows:
controlling the average density of the refrigerant in the refrigeration cycle circuit 4 based on a predetermined control target during self-charging of the refrigerant;
the self-charging of the refrigerant is calculated and completed according to the real-time operation parameters of the refrigeration cycle circuit 4 and the real-time parameters of the outdoor environment.
In this embodiment, specifically, during the refrigerant self-charging process, the plurality of indoor units 2 are controlled to perform cooling operation with a preset air volume, and the opening degree of the outdoor electronic expansion valve 407 is controlled to a maximum value;
based on the control target, the plurality of indoor electronic expansion valves 410, the plurality of indoor heat exchangers 411, the outdoor heat exchanger 406, the gas-liquid separator 403, the compressor 404, the outdoor fan 413, and the bypass electronic expansion valve 408 are controlled to operate in the control target, thereby controlling the refrigerant average density in the refrigeration cycle circuit 4;
the refrigerant self-charging is calculated based on the real-time operating parameters of the compressor 404, the real-time operating parameters of the outdoor heat exchanger 406, and the real-time parameters of the outdoor environment.
When the refrigerant is filled automatically, firstly, the refrigerant filling tank 5 is communicated with the refrigeration cycle circuit 4, the stop valve 6 is opened, the refrigeration cycle circuit 4 is vacuumized or evacuated, so that air enters the refrigeration cycle circuit 4 in the refrigerant self-filling process, the refrigerant self-filling mode is entered through a main control panel dial switch of the outdoor unit 3 or the controller 1 connected with the indoor unit 2, the refrigerant self-filling electromagnetic valve 416 is opened, and after the refrigerant self-filling electromagnetic valve 416 is opened, the refrigerant is filled accurately according to the above mode.
In the present embodiment, specifically referring to fig. 12 to 13, the controller 1 calculates to control the frequency of the compressor 404 and the rotation speed of the outdoor fan 413 to be constant when the first preset functional relationship is satisfied, based on the real-time operation parameter of the compressor 404 and the real-time parameter of the outdoor environment;
and calculating to control to finish the self-charging of the refrigerant when the second preset functional relation is met according to the real-time operation parameters of the outdoor heat exchanger 406 and the real-time parameters of the outdoor environment.
It is noted that when the refrigerant self-charge is completed, the refrigerant self-charge solenoid valve 416 is closed.
More specifically, the first predetermined function relationship is: pd ═ f (Ta)
Wherein the content of the first and second substances,
in the above equation, Pd represents the discharge pressure value of the compressor 404 (which can be acquired by the discharge pressure sensor 421); ta represents an outdoor ambient temperature value (which may be collected by the outdoor temperature sensor 422); a isn、an-1......a1And m1Are all control constants.
The second predetermined function relationship is: SC ═ f (Ta)
Wherein the content of the first and second substances,
in the above formula, SC represents the supercooling degree of the outdoor heat exchanger 406, where the supercooling degree is a difference between a saturation temperature value corresponding to the discharge pressure value of the compressor 404 and an outdoor liquid pipe temperature value (which may be acquired by the outdoor liquid pipe temperature sensor 423); ta represents an outdoor ambient temperature value (which may be collected by the outdoor temperature sensor 422); bn、bn-1......b1And n1Are all control constants.
In the present embodiment, specifically, the dryness of the refrigerant in the plurality of indoor heat exchangers 411 is calculated, the plurality of indoor heat exchangers 411 are controlled to operate with the evaporation pressure control target based on the predetermined dryness of the refrigerant control target and the evaporation pressure control target, and the opening degrees of the plurality of indoor electronic expansion valves 410 are controlled to adjust the dryness of the refrigerant in the plurality of indoor heat exchangers 411 such that the dryness of the refrigerant satisfies the dryness of the refrigerant control target, thereby controlling the average density of the refrigerant in the plurality of indoor heat exchangers 411, the dryness of the refrigerant control target being greater than 0.3, and the evaporation pressure control target being 0.6MPa to 0.9 MPa.
More specifically, as shown in FIG. 5, FIG. 5 shows that the evaporation pressures are p, respectivelye1＝1.5Mpa、pe2＝1.2Mpa、pe3＝0.9Mpa、pe4The change curve of the density of the refrigerant along the dryness of the refrigerant under the condition of 0.6MPa is expressed as the evaporation pressure pe3The evaporation pressure is p respectively based on the density of the refrigerant under different dryness conditions of the refrigerant of 0.9Mpae1＝1.5Mpa、pe2＝1.2Mpa、pe40.6Mpa and evaporation pressure pe3The difference Δ ρ between the refrigerant densities at different dryness values of 0.9MPa is shown in FIG. 6, from which FIG. 6 shows the evaporation pressure pe11.5Mpa and evaporation pressure pe3The difference of the density difference delta rho of the refrigerant under different dryness conditions is larger when the pressure is 0.9 Mpa; evaporation pressure is respectively pe2＝1.2Mpa、pe40.6Mpa and evaporation pressure pe30.9MPa in dry x degree of refrigerant>Refrigerant density difference Δ ρ at 0.3The difference is small, so only the refrigerant quality x at the inlet of the indoor heat exchanger 411 needs to be controlled>0.3, it is ensured that the average density of the refrigerant in the indoor heat exchanger 411 is equivalent under different evaporation pressure conditions. In addition, in the self-filling process of the refrigerant, the indoor temperature range is 10-35 ℃, so the evaporation pressure control target of the embodiment is 0.6-0.9 MPa.
The method for calculating the dryness of the refrigerant at the inlet of the indoor heat exchanger 411 is as follows:
x＝[f(P,T)-f(Tliq)]/[f(Tvap)-f(Tliq)] (9)
in the above formula, x represents the dryness of the refrigerant at the inlet of the indoor heat exchanger 411; f (P, T) represents the enthalpy of the refrigerant at the liquid side stop valve 414, i.e., the enthalpy of the pressure and temperature at the liquid side stop valve 414; f (T)liq) Expressed as the saturated liquid enthalpy; f (T)vap) Expressed as the saturated gas enthalpy.
Regarding f (P, T) in the formula (9), in consideration of a small pressure loss in the refrigeration cycle circuit 4, the pressure value at the liquid-side shutoff valve 414 may be approximated to the discharge port pressure value of the compressor 404 or may be corrected by the discharge port pressure value of the compressor 404; or the pressure sensor 425 at the liquid side stop valve can be added at the liquid stop valve 414 for direct acquisition; the temperature at the liquid stop valve is directly acquired by a temperature sensor 424 at the liquid side stop valve; and calculating the enthalpy value of the liquid side stop valve 414 according to the pressure value and the temperature value. For f (T)liq) And f (T)vap) The temperature value can be calculated by the temperature value acquired by the temperature sensor 427 at the middle position of the indoor heat exchanger 411.
In the present embodiment, specifically, the opening degrees of the plurality of indoor electronic expansion valves 410 are controlled to adjust the degrees of superheat of the plurality of indoor heat exchangers 411 based on an evaporation pressure control target and a predetermined degree of superheat control target, such that the degrees of superheat satisfy the degree of superheat control target, thereby controlling the average density of the refrigerant in the connecting gas pipe 402 and the gas-liquid separator 403, the degree of superheat control target being greater than 10 ℃.
FIG. 7 shows the refrigerant densities at evaporation pressures of 0.6MPa and 0.9MPa, respectivelyThe relationship with the degree of superheat, as shown in FIG. 7, is that the difference in refrigerant density Δ ρ ≈ 10kg/m at different evaporation pressures3The refrigerant density difference is small, so that the average density of the refrigerant connected with the air pipe 402 and the gas-liquid separator 403 can be controlled to be equal only by controlling the evaporation pressure to meet the evaporation pressure control target and controlling the superheat degree to meet the superheat degree control target, the refrigerant filling amount under different conditions is equal, the superheat degree control target can be selected according to the common condition, the superheat degree is not excessive, and the compressor 404 is overheated due to the excessive superheat degree.
In the embodiment, the reliability risk caused by liquid return of the compressor 404 is reduced by a predetermined superheat degree control target, wherein each branch connecting air pipe 402 is provided with an indoor air pipe temperature sensor 428, an intermediate position temperature sensor 427 is arranged at the intermediate position of each indoor heat exchanger 411, and the superheat degree of each indoor heat exchanger 411 is obtained by subtracting the temperature value acquired by the intermediate position temperature sensor 427 in the indoor heat exchanger 411 from the temperature value acquired by the indoor air pipe temperature sensor 428.
In the present embodiment, specifically, the compressor 404 is controlled to operate with the evaporation pressure control target of 0.6MPa to 0.9MPa, taking into account the pressure loss between the connecting gas pipes 402, as the suction pressure based on the evaporation pressure control target, thereby controlling the average density of the refrigerant in the compressor 404.
In the present embodiment, specifically, the outdoor heat exchanger 406 and the outdoor fan 413 are controlled to operate with the condensing pressure control target, respectively, based on the condensing pressure control target determined in advance, so as to control the average density of the refrigerant in the outdoor heat exchanger 406, the condensing pressure control target being 2.3MPa to 3.0 MPa.
More specifically, FIG. 8 shows that the condensing pressures are p, respectivelyc1＝3.5Mpa、pc2＝3.0Mpa、pc3＝2.7Mpa、pc4＝2.3Mpa、pc5When the superheated refrigerant density changes at 2.0Mpa, the condensing pressure is p, as shown in fig. 8c1＝3.5Mpa、pc52.0MPa and a condensing pressure ofpc3Since the density difference between 2.7MPa is large, the control target of the condensation pressure in this example is 2.3MPa to 3.0MPa, and the corresponding average densities are 75kg/m, respectively3、88kg/m3、99kg/m3. The average density of the refrigerant is comparable for the compressor section, and the amount of refrigerant charged is comparable in each case. Since the compressor 404 generally has a suction pressure as a control target, which is approximately equal to the evaporation pressure, the evaporation pressure is a control target for the compressor 404 portion. The evaporation pressure control target of the present embodiment is preferably 0.7Mpa in consideration of the pressure loss between the connecting gas pipes 402.
More specifically, FIG. 9 shows the condensing pressures pc1＝3.5Mpa、pc2＝3.0Mpa、pc3＝2.7Mpa、pc4＝2.3Mpa、pc52.0Mpa, the density of two-phase refrigerant changes; FIG. 10 is a graph of the average density of two-phase refrigerant at different condensing pressure conditions; FIG. 11 shows the respective condensing pressures pc1＝3.5Mpa、pc2＝3.0Mpa、pc3＝2.7Mpa、pc4＝2.3Mpa、pc5When the average density and the supercooling degree of the liquid-phase refrigerant are changed under 2.0MPa, the average density of the corresponding refrigerant is 1019kg/m3、1041kg/m3、1051kg/m3、1071kg/m3、1085kg/m3. In the further embodiment, the condensing pressure is controlled to be 2.3-3.0 MPa, and the average densities of the corresponding superheated refrigerants are 75kg/m3、88kg/m3、99kg/m3(ii) a The average density of the corresponding two-phase refrigerant is 256kg/m3、289kg/m3、312kg/m3(ii) a The average densities of the corresponding liquid refrigerants are 1071kg/m3、1051kg/m3、1041kg/m3. Further condensation pressure of 2.3 to 3.0MPa corresponding to an average density of about 467kg/m3、476kg/m3、484kg/m3. For the outdoor heat exchanger 406, when the outdoor heat exchanger 406 is controlled to operate with the condensing pressure control target, the average density of the refrigerant in the outdoor heat exchanger 406 can be made equal, and the refrigerant can be charged in different situationsThe amount of injected refrigerant was comparable.
In the present embodiment, specifically, the opening degree of the bypass electronic expansion valve 408 is controlled to adjust the supercooling degree of the outdoor heat exchanger 406 based on the supercooling degree control target and the condensing pressure control target determined in advance such that the supercooling degree satisfies the supercooling degree control target, thereby controlling the refrigerant average density in the connecting liquid pipe 401, the supercooling degree control target being greater than 15 ℃.
More specifically, the refrigerant in the connecting liquid pipe 401 needs to be in a liquid state, fig. 11 shows the variation of the density and the supercooling degree of the liquid refrigerant under different condensing pressures, the condensing pressure control target is 2.3-3.0 MPa, and the average density of the refrigerant is not greatly different; fig. 9 shows the change of the density of the two-phase refrigerant, and when the refrigerant dryness x is 0.05, the refrigerant density is greatly reduced. For the liquid connecting pipe 401, the refrigerant can be ensured to be in a liquid state only by controlling the condensing pressure to meet the condensing pressure control target and controlling the supercooling degree to meet the supercooling degree control target, so that the average density of the refrigerant of the liquid connecting pipe 401 is controlled to be equal, and the amount of the filled refrigerant is controlled to be equal under different conditions. The present embodiment prevents the flash of the liquid refrigerant and the large change in the refrigerant density in the connecting liquid pipe 401 caused by the pressure loss of the connecting liquid pipe 401 by the predetermined supercooling degree control target.
Referring to fig. 14, when the refrigerant self-charging is completed, the error between the refrigerant charge and the target refrigerant charge is ± a% and ± a% is ± 15% under different conditions by using the method of embodiment one, which satisfies the requirement of the actual engineering.
The multi-split air conditioner provided by the embodiment controls the average density of the refrigerant in the refrigeration cycle loop 4 based on the predetermined control target, realizes the accurate filling of the refrigerant amount in the updating process of the multi-split air conditioner, solves the problem that the comfort and reliability of the multi-split air conditioner are influenced due to the fact that the refrigerant cannot be accurately added in the updating process of the multi-split air conditioner, improves the comfort and reliability of the multi-split air conditioner, and further improves the experience of customers.
Example two
The present embodiment provides a multi-split air conditioner, referring to fig. 15, the configuration of which is substantially the same as that of the first embodiment, except that a refrigerant self-charging solenoid valve 416 and a first capillary tube 417 are used, in the present embodiment, the refrigerant self-charging solenoid valve 416 and the first capillary tube 417 are replaced with a refrigerant self-charging electronic expansion valve 418, and the rate of automatic charging of refrigerant is controlled by the refrigerant self-charging electronic expansion valve 418.
A refrigerant self-charging process, in which after entering a refrigerant self-charging mode through a dial switch of a main control panel of the outdoor unit 3 or the controller 1 connected with the indoor unit 2, the refrigerant self-charging electronic expansion valve 418; when the refrigerant self-charge is complete, the refrigerant self-charging electronic expansion valve 418 is closed.
EXAMPLE III
In the third embodiment, the multi-split air conditioner is a multi-split air outlet unit, and referring to fig. 16, the multi-split air conditioner has substantially the same structure as the first embodiment, except for the structure of the outdoor heat exchanger 406. The outdoor heat exchanger 406 in this embodiment includes: a first outdoor heat exchanger 4061, a second outdoor heat exchanger 4062, and a third outdoor heat exchanger 4063 that are arranged in the vertical direction (from top to bottom);
the top of the first outdoor heat exchanger 4061 is provided with an outdoor fan 413, and the first outdoor heat exchanger 4061 is communicated with the compressor 404 through a connecting liquid pipe 401;
the second outdoor heat exchanger 4062 is communicated with the compressor 404 through a connecting liquid pipe 401, and the second outdoor heat exchanger 4062 is also connected in parallel with the first outdoor heat exchanger 4061;
the third outdoor heat exchanger 4063 is connected to the plurality of indoor heat exchangers 411 through the connecting liquid pipe 401, and the third outdoor heat exchanger 4063 is connected in series to the first outdoor heat exchanger 4061 and also connected in series to the second outdoor heat exchanger 4062.
Referring to fig. 17, when the outdoor fan 413 is located at the top of the outdoor heat exchanger 406, the wind speed of the portion close to the outdoor fan 413 is high, and the wind speed of the portion far from the outdoor fan 413 is low, so that the multi-split air conditioner provided by the present embodiment can avoid the above problems, increase the supercooling degree of the outdoor heat exchanger 406, and further increase the supercooling degree after passing through the supercooling heat exchanger 409, thereby ensuring that the refrigerant in the connecting liquid pipe 401 is in a liquid state, and further increasing the accuracy of refrigerant self-charging.
Example four
In the fourth embodiment, the multi-split air conditioner is a multi-split air outlet unit, and referring to fig. 18, the multi-split air conditioner has substantially the same structure as the first embodiment, except for the structure of the outdoor heat exchanger 406. The outdoor heat exchanger 406 in this embodiment includes: a first outdoor heat exchanger 4061, a second outdoor heat exchanger 4062, a third outdoor heat exchanger 4063, and a fourth outdoor heat exchanger 4064 that are arranged in the vertical direction (from top to bottom);
the outdoor fan 413 includes: a first outdoor fan 4131 and a second outdoor fan 4132, the first outdoor fan 4131 being disposed on the same side as the first outdoor heat exchanger 4061 and the second outdoor heat exchanger 4062, the second outdoor fan 4132 being disposed on the same side as the third outdoor heat exchanger 4063 and the fourth outdoor heat exchanger 4064;
the first outdoor heat exchanger 4061 is communicated with the compressor 404 through a connecting liquid pipe 401, and the first outdoor heat exchanger 4061 is also connected in series with the second outdoor heat exchanger 4062;
the fourth outdoor heat exchanger 4064 is communicated with the compressor 404 through the connecting liquid pipe 401, and the fourth outdoor heat exchanger 4064 is further connected in series with the third outdoor heat exchanger 4063;
the second outdoor heat exchanger 4062 and the third outdoor heat exchanger 4063 are connected in parallel, and parallel branches thereof communicate with the plurality of indoor heat exchangers 411.
Referring to fig. 19, when the outdoor fan 413 is located at one side of the outdoor heat exchanger 406, the wind speed at the middle position of the outdoor heat exchanger 406 is the smallest, and the multi-split air conditioner provided according to the embodiment can avoid the above problems, so that the supercooling degree of the outdoor heat exchanger 406 is increased, the supercooling degree can be further increased after the outdoor heat exchanger 409 is cooled, the refrigerant in the liquid connection pipe 401 is ensured to be in the liquid state, and the accuracy of automatic refrigerant charging is further increased.
EXAMPLE five
The control method of the multi-split air conditioner provided by this embodiment is applied to the multi-split air conditioner described in the first embodiment, the second embodiment, the third embodiment, or the fourth embodiment, where, referring to fig. 20, the control method includes:
s1: controlling the average density of the refrigerant in the refrigeration cycle circuit 4 based on a predetermined control target during self-charging of the refrigerant;
s2: the self-charging of the refrigerant is calculated and completed according to the real-time operation parameters of the refrigeration cycle circuit 4 and the real-time parameters of the outdoor environment.
In this embodiment, specifically, the step S1 includes:
in the refrigerant self-charging process, controlling a plurality of indoor units 2 to perform refrigeration operation at a preset air volume, and controlling the opening degree of the outdoor electronic expansion valve 407 to be the maximum value;
based on the control target, the plurality of indoor electronic expansion valves 410, the plurality of indoor heat exchangers 411, the outdoor heat exchanger 406, the gas-liquid separator 403, the compressor 404, the outdoor fan 413, and the bypass electronic expansion valve 408 are controlled to operate in the control target, thereby controlling the refrigerant average density in the refrigeration cycle circuit 4;
the refrigerant self-charging is calculated based on the real-time operating parameters of the compressor 404, the real-time operating parameters of the outdoor heat exchanger 406, and the real-time parameters of the outdoor environment.
In this embodiment, the method for controlling the average density of the refrigerant in the plurality of indoor heat exchangers 411 specifically includes:
calculating the dryness of the refrigerant of the indoor heat exchangers 411, controlling the indoor heat exchangers 411 to operate with an evaporation pressure control target based on a predetermined refrigerant dryness control target and an evaporation pressure control target, and controlling the opening degree of the indoor electronic expansion valves 410 to adjust the dryness of the refrigerant of the indoor heat exchangers 411 so that the dryness of the refrigerant meets the refrigerant dryness control target, thereby controlling the average density of the refrigerant in the indoor heat exchangers 411, wherein the refrigerant dryness control target is more than 0.3, and the evaporation pressure control target is 0.6-0.9 MPa.
In this embodiment, the method for controlling the average density of the refrigerant in the connection gas pipe 402 and the gas-liquid separator 403 specifically includes:
on the basis of the evaporation pressure control target and the predetermined superheat degree control target, the opening degrees of the plurality of indoor electronic expansion valves 410 are controlled to adjust the superheat degrees of the plurality of indoor heat exchangers 411 so that the superheat degrees satisfy the superheat degree control target, thereby controlling the average refrigerant density of the refrigerant in the connecting gas pipe 402 and the gas-liquid separator 403, with the superheat degree control target being greater than 10 ℃.
In this embodiment, the method for controlling the average density of the refrigerant in the compressor 404 specifically includes:
based on the evaporation pressure control target, the compressor 404 is controlled to operate with the evaporation pressure control target as a suction pressure operation, thereby controlling the refrigerant average density in the compressor 404. In the present embodiment, the evaporation pressure control target is preferably 0.7Mpa in consideration of the pressure loss between the connecting manifolds.
In this embodiment, the method for controlling the average density of the refrigerant in the outdoor heat exchanger 406 specifically includes:
and controlling the outdoor heat exchanger 406 and the outdoor fan 413 to respectively operate at the condensation pressure control target based on the predetermined condensation pressure control target, so as to control the average density of the refrigerant in the outdoor heat exchanger 406, wherein the condensation pressure control target is 2.3 MPa-3.0 MPa.
In this embodiment, the method for controlling the average density of the refrigerant in the connecting liquid pipe 401 specifically includes:
based on the pre-determined supercooling degree control target and the condensation pressure control target, the opening degree of the bypass electronic expansion valve 408 is controlled to adjust the supercooling degree of the outdoor heat exchanger 406 so that the supercooling degree meets the supercooling degree control target, thereby controlling the average density of the refrigerant in the connecting liquid pipe 401, wherein the supercooling degree control target is more than 15 ℃.
In this embodiment, specifically, the step S2 includes:
calculating to control the frequency of the compressor 404 and the rotating speed of the outdoor fan 413 to be kept unchanged when the first preset functional relationship is satisfied according to the real-time operation parameters of the compressor 404 and the real-time parameters of the outdoor environment;
and calculating to control to finish the self-charging of the refrigerant when the second preset functional relation is met according to the real-time operation parameters of the outdoor heat exchanger 406 and the real-time parameters of the outdoor environment.
The control method for the multi-split air conditioner provided by the embodiment controls the average density of the refrigerant in the refrigeration cycle circuit 4 based on the predetermined control target, realizes the accurate filling of the refrigerant amount in the updating process of the multi-split air conditioner, solves the problem that the comfort and the reliability of the multi-split air conditioner are influenced due to the fact that the refrigerant cannot be accurately added in the updating process of the multi-split air conditioner, improves the comfort and the reliability of the multi-split air conditioner, and further improves the experience of a client.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims (10)
1. A multi-split air conditioner comprising a plurality of indoor units, an outdoor unit, a controller, and a refrigeration cycle circuit for connecting the plurality of indoor units and the outdoor unit, wherein the controller is configured to:
controlling an average density of refrigerant in the refrigeration cycle circuit based on a predetermined control target during self-charging of the refrigerant;
and calculating to complete the self-charging of the refrigerant according to the real-time operation parameters of the refrigeration cycle loop and the real-time parameters of the outdoor environment.
2. A multi-split air conditioner as set forth in claim 1, wherein said refrigerating cycle circuit comprises: the air-liquid separator, the compressor, the outdoor heat exchanger, the outdoor electronic expansion valve, the bypass electronic expansion valve, the indoor electronic expansion valves and the indoor heat exchangers are connected through the connecting liquid pipe and the connecting air pipe, and the outdoor heat exchanger is provided with the outdoor fan.
3. The multi-split air conditioner as claimed in claim 2, wherein the controller is further configured to:
in the refrigerant self-filling process, controlling a plurality of indoor units to perform refrigeration operation at a preset air volume, and controlling the opening degree of the outdoor electronic expansion valve to be the maximum value;
controlling the plurality of indoor electronic expansion valves, the plurality of indoor heat exchangers, the outdoor heat exchanger, the gas-liquid separator, the compressor, the outdoor fan, and the bypass electronic expansion valve to operate in the control target operation based on the control target, thereby controlling the average refrigerant density of the refrigerant in the refrigeration cycle circuit;
calculating to complete the self-filling of the refrigerant according to the real-time operation parameters of the compressor, the real-time operation parameters of the outdoor heat exchanger and the real-time parameters of the outdoor environment;
more preferably, the controller is further configured to: and controlling the outdoor heat exchanger and the outdoor fan to respectively operate at the condensation pressure control target based on the predetermined condensation pressure control target, so as to control the average density of the refrigerant in the outdoor heat exchanger, wherein the condensation pressure control target is 2.3-3.0 MPa.
4. The multi-split air conditioner as claimed in claim 3, wherein the controller is further configured to:
calculating to control the frequency of the compressor and the rotating speed of the outdoor fan to be kept unchanged when a first preset functional relation is met according to the real-time operation parameters of the compressor and the real-time parameters of the outdoor environment;
and according to the real-time operation parameters of the outdoor heat exchanger and the real-time parameters of the outdoor environment, calculating and controlling to finish the self-charging of the refrigerant when a second preset functional relation is met.
5. The multi-split air conditioner as claimed in claim 3, wherein the controller is further configured to:
calculating the dryness of the refrigerant of the indoor heat exchangers, controlling the indoor heat exchangers to work under the control target of the evaporation pressure based on the predetermined control target of the dryness of the refrigerant and the control target of the evaporation pressure, and controlling the opening degree of the indoor electronic expansion valves to adjust the dryness of the refrigerant of the indoor heat exchangers so that the dryness of the refrigerant meets the control target of the dryness of the refrigerant, thereby controlling the average density of the refrigerant in the indoor heat exchangers, wherein the control target of the dryness of the refrigerant is more than 0.3, and the control target of the evaporation pressure is 0.6-0.9 MPa.
6. The multi-split air conditioner as claimed in claim 5, wherein the controller is further configured to:
controlling the compressor to operate with the evaporation pressure control target as a suction pressure operation based on the evaporation pressure control target, thereby controlling an average density of the refrigerant in the compressor.
7. The multi-split air conditioner as claimed in claim 5, wherein the controller is further configured to:
controlling opening degrees of a plurality of the indoor electronic expansion valves to adjust a superheat degree of a plurality of the indoor heat exchangers based on the evaporation pressure control target and a predetermined superheat degree control target, such that the superheat degree satisfies the superheat degree control target, thereby controlling an average density of the refrigerant in the connecting gas pipe and the gas-liquid separator, the superheat degree control target being greater than 10 ℃.
8. The multi-split air conditioner as claimed in claim 3, wherein the controller is further configured to:
and controlling the opening degree of the bypass electronic expansion valve to adjust the supercooling degree of the outdoor heat exchanger based on a predetermined supercooling degree control target and the condensation pressure control target, so that the supercooling degree meets the supercooling degree control target, the average density of the refrigerant in the connecting liquid pipe is controlled, and the supercooling degree control target is more than 15 ℃.
9. A multi-split air conditioner as recited in claim 2, wherein said outdoor heat exchanger comprises: the first outdoor heat exchanger, the second outdoor heat exchanger and the third outdoor heat exchanger are sequentially arranged along the vertical direction;
the top of the first outdoor heat exchanger is provided with the outdoor fan, and the first outdoor heat exchanger is communicated with the compressor through the connecting liquid pipe;
the second outdoor heat exchanger is communicated with the compressor through the connecting liquid pipe and is also connected with the first outdoor heat exchanger in parallel;
the third outdoor heat exchanger is communicated with the plurality of indoor heat exchangers through the connecting liquid pipes, and is connected with the first outdoor heat exchanger in series and also connected with the second outdoor heat exchanger in series;
or the outdoor heat exchanger includes: the first outdoor heat exchanger, the second outdoor heat exchanger, the third outdoor heat exchanger and the fourth outdoor heat exchanger are sequentially arranged along the vertical direction;
the outdoor fan includes: the first outdoor fan is arranged on the same side of the first outdoor heat exchanger and the second outdoor heat exchanger, and the second outdoor fan is arranged on the same side of the third outdoor heat exchanger and the fourth outdoor heat exchanger;
the first outdoor heat exchanger is communicated with the compressor through the connecting liquid pipe and is also connected with the second outdoor heat exchanger in series;
the fourth outdoor heat exchanger is communicated with the compressor through the connecting liquid pipe and is also connected with the third outdoor heat exchanger in series;
the second outdoor heat exchanger and the third outdoor heat exchanger are connected in parallel, and parallel branches of the second outdoor heat exchanger and the third outdoor heat exchanger are communicated with the plurality of indoor heat exchangers.
10. A control method of a multi-split air conditioner, applied to the multi-split air conditioner as set forth in any one of claims 1 to 9, comprising:
controlling an average density of refrigerant in the refrigeration cycle circuit based on a predetermined control target during self-charging of the refrigerant;
and calculating to complete the self-charging of the refrigerant according to the real-time operation parameters of the refrigeration cycle loop and the real-time parameters of the outdoor environment.
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| CN114017891A (en) * | 2021-11-11 | 2022-02-08 | 青岛海信日立空调系统有限公司 | Air conditioner |
| WO2023083040A1 (en) * | 2021-11-11 | 2023-05-19 | 青岛海信日立空调系统有限公司 | Air conditioner |
| CN114165845A (en) * | 2021-11-26 | 2022-03-11 | 青岛海信日立空调系统有限公司 | Multi-split air conditioner |
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| CN113266929B (en) | 2022-10-04 |
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