CN111397239B - Multi-split air conditioning system and method for reducing noise of multi-split air conditioning system - Google Patents

Multi-split air conditioning system and method for reducing noise of multi-split air conditioning system Download PDF

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Publication number
CN111397239B
CN111397239B CN202010175325.9A CN202010175325A CN111397239B CN 111397239 B CN111397239 B CN 111397239B CN 202010175325 A CN202010175325 A CN 202010175325A CN 111397239 B CN111397239 B CN 111397239B
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valve
auxiliary
pipeline
conditioning system
air conditioning
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CN111397239A (en
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刘东来
杨春雪
侯志辉
史传民
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Hisense Air Conditioning Co Ltd
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Hisense Shandong Air Conditioning Co Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B13/00—Compression machines, plants or systems, with reversible cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/62—Control or safety arrangements characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
    • F24F11/63—Electronic processing
    • F24F11/64—Electronic processing using pre-stored data
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
    • F24F13/24—Means for preventing or suppressing noise
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
    • F24F13/30—Arrangement or mounting of heat-exchangers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
    • F24F3/06—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the arrangements for the supply of heat-exchange fluid for the subsequent treatment of primary air in the room units
    • F24F3/065—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the arrangements for the supply of heat-exchange fluid for the subsequent treatment of primary air in the room units with a plurality of evaporators or condensers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B40/00—Subcoolers, desuperheaters or superheaters
    • F25B40/02—Subcoolers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
    • F24F13/24—Means for preventing or suppressing noise
    • F24F2013/247—Active noise-suppression
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
    • F25B2313/027—Compression machines, plants or systems with reversible cycle not otherwise provided for characterised by the reversing means
    • F25B2313/02741—Compression machines, plants or systems with reversible cycle not otherwise provided for characterised by the reversing means using one four-way valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2500/00—Problems to be solved
    • F25B2500/12—Sound

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Signal Processing (AREA)
  • Fuzzy Systems (AREA)
  • Mathematical Physics (AREA)
  • Air Conditioning Control Device (AREA)
  • Compression-Type Refrigeration Machines With Reversible Cycles (AREA)

Abstract

The invention provides a multi-split air conditioning system and a method for reducing noise of the multi-split air conditioning system. The heat exchanger also comprises a main loop consisting of the electronic expansion valve, the heat exchanger and a main pipeline; the method for reducing the noise of the multi-split air conditioning system has the advantages that the judgment process is flexible and simple, the on-off control is carried out on the refrigerant in the auxiliary loop through the electromagnetic valve, the refrigerant is opened timely, and the control is flexible.

Description

Multi-split air conditioning system and method for reducing noise of multi-split air conditioning system
Technical Field
The invention belongs to the technical field of air conditioners, and particularly relates to a multi-split air conditioning system and a method for reducing noise of the multi-split air conditioning system.
Background
The multi-split air conditioning system comprises a plurality of indoor units which are used in parallel, wherein each indoor unit comprises an indoor heat exchanger and an indoor electronic expansion valve. When the indoor unit performs refrigeration operation, when the degree of supercooling in front of a valve of an electronic expansion valve of the indoor unit is insufficient, namely the refrigerant state in front of the valve is a gas-liquid two-phase state, obvious indoor throttling noise can be generated. This problem has been one of the most feedback and difficult to solve in the market.
To solve the problem, the following scheme is adopted in the prior art:
1. the control parameter value of the supercooling degree before the electronic expansion valve is increased, so that the supercooling degree of the refrigerant is still maintained before the refrigerant reaches the expansion valve of the indoor unit after the refrigerant flows to overcome the on-way resistance loss and on-way heat loss of the pipeline;
2. the electronic expansion valve of the indoor unit is additionally wrapped by a damping block, so that the refrigerant throttling sound caused by the supercooling degree in front of the abnormal valve is reduced;
3. the brass parts are added in the field, and the purpose of reducing throttling sound is achieved by destroying the state of two-phase refrigerants in front of and behind the valve.
Although the scheme can achieve the purpose of improving the supercooling degree by adding a quantitative refrigerant or adding secondary supercooling equipment, the extra cost is increased, and meanwhile, the operation power of the whole machine is increased due to the increase of the refrigerant quantity. The method for binding the damping block and welding the brass piece is only effective for most of more conventional installation and use environments, is not suitable for all installation environments, and cannot be widely popularized. When the individual indoor unit is used for long-distance cold conveying, the refrigerant before the electronic expansion valve of the indoor unit still has no supercooling degree due to the on-way resistance loss and the heat loss, so that the hidden trouble of throttling sound is generated when a user operates the indoor unit for refrigeration.
Disclosure of Invention
The invention provides a method for reducing noise of a multi-split air-conditioning system by increasing the supercooling degree in front of an electronic expansion valve of an indoor unit and the multi-split air-conditioning system, aiming at the technical problem that throttling sound is easily generated in the indoor unit when the multi-split air-conditioning system operates in a refrigerating mode.
In order to achieve the purpose, the invention adopts the technical scheme that:
a multi-split air conditioning system comprises
An outdoor unit;
the indoor unit set includes several parallelly connected indoor units, and each indoor unit has electronic expansion valve and heat exchanger.
It is characterized by also comprising
The electronic expansion valve, the heat exchanger and a main pipeline form a main loop, and the main pipeline is a pipeline positioned at the inlet end of the electronic expansion valve, a pipeline positioned at the outlet end of the electronic expansion valve and the inlet end of the heat exchanger, and a pipeline positioned at the inlet end of the heat exchanger;
the auxiliary loop comprises a recooler, a first auxiliary pipeline and a second auxiliary pipeline, and a small amount of refrigerant throttled by the electronic expansion valve is introduced into the recooler to be cooled so as to reduce the temperature of the refrigerant flowing into the main loop of the indoor unit;
the first auxiliary pipeline is arranged between the outlet end of the electronic expansion valve and the inlet of the sub-cooler, and introduces the refrigerant after the electronic expansion valve into the sub-cooler for sub-cooling; one end of the second auxiliary pipeline is connected with the outlet of the recooler, and the other end of the second auxiliary pipeline is connected with a main loop of the outlet of the heat exchanger; the pressure loss for the auxiliary circuit is less than the pressure loss before and after the heat exchanger.
In some embodiments of this application, be provided with the check valve on the second auxiliary line, during the operation of heating, close auxiliary circuit promotes indoor unit's reliability.
In some embodiments of the present application, an electronic valve is disposed on the first auxiliary line to enable starting and closing of the auxiliary circuit.
Some embodiments in this application, hollow cylindric sleeve pipe in the spiral pipe outside is located including spiral pipe and cover to the recooler, the spiral pipe is for being located part before the electronic expansion valve the main line improves and forms, sheathed tube both ends respectively with first auxiliary line with the second auxiliary line is connected, the intraductal refrigerant of cover is the double-phase low temperature refrigerant of gas-liquid behind electronic expansion valve's the valve for the spiral pipe cooling reaches the recooling purpose.
In some embodiments of the present application, the sleeve is spirally wound on an outer side of the spiral pipe, and the sleeve is a part of the first/second auxiliary pipe.
Some embodiments in this application, the off-premises station is including connecting liquid storage pot, compressor, outdoor heat exchanger and outdoor electronic expansion valve in order, the compressor reaches be connected with the cross valve between the outdoor heat exchanger, the cross valve still connect with the compressor reaches between the liquid storage pot, and the compressor with between the indoor set, the refrigerant after will passing through the compressor is in the liquid storage pot outdoor heat exchanger and convey between the indoor set.
Based on the multi-split air conditioning system, the invention also provides a method for reducing the noise of the multi-split air conditioning system, which is characterized by comprising the following steps:
s1: degree of supercooling SC before preset valveP；
S2: during the refrigeration operation, the pre-valve supercooling degree SC of the electronic expansion valve 21 of each starting indoor unit is detected, and the detected pre-valve supercooling degree SC and the preset pre-valve supercooling degree SC are comparedPComparing;
s3: when SC < SCPWhen the temperature of the main loop is higher than the preset temperature, the electronic valve is opened, the auxiliary loop is opened, and the main loop and the auxiliary loop are cooperatively refrigerated;
when SC is more than or equal to SCPAnd closing the electronic valve, closing the auxiliary loop and executing the refrigeration process of the main loop.
In some embodiments of the present application, the pre-valve supercooling degree SC is calculated as SC ═ Tpd-Tin-Δt，
Wherein, TpdThe outdoor condensing pressure corresponds to the saturation temperature,
Tinis the temperature of the refrigerant before the electronic expansion valve,
and delta t is a pipeline correction coefficient of reduced supercooling degree caused by the on-way resistance loss and heat loss of the pipeline.
In some embodiments of the present application, the SCPIs 1 to 6.
Compared with the prior art, the invention has the advantages and positive effects that:
1. on the basis of the original main loop of the indoor unit of the multi-split air-conditioning system, the auxiliary loop is added, and the inlet and outlet pipelines of the main loop of the indoor unit are adjacent, so that the auxiliary loop is very short, the resistance of the refrigerant in the auxiliary loop is not obviously reduced, after the refrigerant is re-cooled by the auxiliary loop, the degree of supercooling of the refrigerant before a valve is improved, and the refrigerating capacity of the refrigerant with unit mass flow is also indirectly improved;
2. the refrigerant in the auxiliary loop is heated by the refrigerant in the main loop, is changed into a low-pressure gaseous medium-temperature refrigerant with the temperature between that of the main loop and that of the auxiliary loop before heat exchange, and is converged with the refrigerant at the outlet of the heat exchanger through the check valve, so that the superheat degree of the outlet of the heat exchanger can be improved, and the reliability of the indoor unit is improved;
3. the method for reducing the noise of the multi-split air conditioning system is flexible and simple in judgment process, and the refrigerant of the auxiliary loop is controlled to be switched on and off through the electronic valve, is started timely and is flexibly controlled.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural view of a multi-split air conditioning system according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a first embodiment of the present invention;
FIG. 3 is a schematic structural diagram of a second embodiment of the present invention;
FIG. 4 is a schematic structural diagram of a third embodiment of the present invention;
FIG. 5 is a schematic structural diagram of a fourth embodiment of the present invention;
figure 6 is a pressure enthalpy diagram for the third embodiment of the present invention;
fig. 7 is a flowchart illustrating a method for reducing noise of a multi-split air conditioning system according to the present invention.
In the above figures: 10. an outdoor unit; 11. a compressor; 12. a liquid storage tank; 13. an outdoor heat exchanger; 14. an outdoor electronic expansion valve; 15. a four-way valve; 20. an indoor unit; 21. an electronic expansion valve; 22. a heat exchanger; 23. a main line, 24, a recooler; 25. a first auxiliary line; 26. a second auxiliary line, 27, a one-way valve; 28. an electronic valve.
Detailed Description
The invention is described in detail below by way of exemplary embodiments. It should be understood, however, that elements, structures and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.
In the description of the present invention, 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 of description and simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.
The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; 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 in specific cases to those skilled in the art.
For better understanding of the above technical solutions, the following detailed descriptions are provided with reference to the accompanying drawings and specific embodiments.
During refrigeration operation, the control of the multi-split air conditioning system on the supercooling degree of a refrigerant in front of an electronic expansion valve is usually based on experiments, and the supercooling degree of an outlet at the side of a liquid stop valve is generally controlled to be 5-8 ℃. When the auxiliary supercooling equipment is not available, if the supercooling degree is too large, the volume in the effective outdoor heat exchanger is occupied, and the heat exchange efficiency of the whole machine is influenced. On the other hand, because the installation and use environment of the indoor unit is complex, even if the supercooling degree of the outlet of the liquid stop valve of the outdoor unit is enough, the supercooling degrees before reaching the expansion valves of the cushions of different indoor units are inconsistent due to the on-way resistance loss and the heat loss, and in serious cases, no supercooling degree exists in front of the electronic expansion valves of part of the indoor units, so that throttling sound is generated.
In view of the above situation, to ensure that the degree of supercooling of the indoor electronic expansion valve 21 before the indoor unit 20 is started during cooling operation, the present invention provides a multi-split air conditioning system, as shown in fig. 1 to 3, including: the indoor unit 10 comprises a plurality of indoor units connected in parallel, and the indoor units are installed in different spaces and used for adjusting indoor temperature; a heat exchanger 22 and an electronic expansion valve 21 are arranged in the indoor unit, and the heat exchanger 22 throttles the refrigerant flowing into the heat exchanger 22 during refrigeration; the electronic expansion valve 21, the heat exchanger 22 and the main pipeline 23 form a main loop L, the main pipeline 23 is a pipeline connecting all components in the indoor unit, and in the embodiment of the invention, the main loop L mainly relates to a pipeline positioned at an inlet end of the electronic expansion valve 21, a pipeline between an outlet end of the electronic expansion valve 21 and an inlet end of the heat exchanger 22 and a pipeline at an outlet end of the heat exchanger 22; the invention also comprises an auxiliary loop M, wherein the auxiliary loop M comprises a recooler 24, a first auxiliary pipeline 25 and a second auxiliary pipeline 26, the first auxiliary pipeline 25 is arranged between the outlet end of the electronic expansion valve 21 and the inlet of the recooler 24, and the refrigerant after the electronic expansion valve 21 is introduced into the recooler 24 for recooling; one end of the second auxiliary pipeline 26 is connected with an outlet of the recooler 24, the other end of the second auxiliary pipeline is connected with a main loop behind the heat exchanger 22, the auxiliary loop M leads a small amount of refrigerant flowing through the electronic expansion valve 21 after throttling into the recooler 24 for cooling, the temperature of the refrigerant flowing into the main loop of the indoor unit is reduced, the pressure loss of the auxiliary loop is smaller than the pressure loss of the front and the rear of the heat exchanger, and the effectiveness of the auxiliary loop M is ensured.
As a first embodiment of the multi-split air conditioning system of the present invention, as shown in fig. 2, in order to improve the reliability of the operation of the indoor unit 20, a check valve 27 is disposed on the second auxiliary pipeline 26, so that during heating operation, the auxiliary circuit M can be closed, and refrigerant does not flow through the auxiliary circuit M, thereby improving the reliability of the indoor unit; the recooler 24 comprises a spiral pipe and a hollow cylindrical sleeve (not shown in the figure) sleeved outside the spiral pipe, the spiral pipe is formed by reforming a part of a main pipeline 23 positioned in front of the electronic expansion valve 21, two ends of the sleeve are respectively connected with a first auxiliary pipeline 25 and a second auxiliary pipeline 26, specifications of the spiral pipe can be designed as required, spiral pipe forms of different specifications are designed, and a refrigerant in the sleeve is a gas-liquid two-phase low-temperature refrigerant behind the electronic expansion valve 21 and used for cooling the spiral pipe, so that the recooler purpose is achieved. No matter whether the degree of supercooling before the valve meets the preset value or not, the auxiliary loop M is always effective, so that the auxiliary loop M cannot be controlled, and when the degree of supercooling before the valve meets the requirement, the auxiliary loop is started, and waste is caused.
As a second embodiment of the multi-split air conditioning system according to the present invention, as shown in fig. 3, the difference from the first embodiment is that the casing of the sub-cooler 24 is spiral and is wound outside the spiral pipe modified by a part of the main pipeline 23, and the casing is modified by a part of the first auxiliary pipeline 25 and/or the second auxiliary pipeline 26, the sub-cooler 24 of the embodiment has low heat exchange efficiency and large capillary resistance, which cannot ensure that the auxiliary loop M can smoothly flow to the outlet pipe of the heat exchanger 22, and cannot ensure the purpose of sub-cooling, and the auxiliary loop M of the embodiment is also always effective.
As a third embodiment of the present invention, the difference from the first embodiment is that the electronic valve 28 is provided on the first auxiliary line 25 to start and close the auxiliary circuit, and compared with the first and second embodiments, the auxiliary circuit M can be opened timely and controlled flexibly, which is the best embodiment.
As a fourth embodiment of the present invention, the difference from the second embodiment is that an electronic valve 28 is disposed on the first auxiliary line 25 to start and close the auxiliary circuit, and compared with the first and second embodiments, the auxiliary circuit M can be timely opened and flexibly controlled, but due to the spiral pattern of the casing, the heat exchange efficiency of the recooler 24 is low and the resistance of the capillary tube is large, so that the auxiliary circuit M cannot smoothly flow to the outlet pipe of the heat exchanger 22, and the recooling purpose cannot be guaranteed.
The outdoor unit 10 includes a liquid storage tank 12, a compressor 11, an outdoor heat exchanger 13 and an outdoor electronic expansion valve 14 connected in sequence, and the connection relationship is known to those skilled in the art, so the present invention is not described herein. A four-way valve 15 is connected between the compressor 11 and the outdoor heat exchanger 13, the four-way valve 15 is further connected between the compressor 11 and the liquid storage tank 12, and between the compressor 11 and the indoor unit 20, and transmits the refrigerant passing through the compressor 11 among the liquid storage tank 12, the outdoor heat exchanger 13 and the indoor unit 20.
Based on the multi-split air conditioning system, the invention also provides a method for reducing the noise of the multi-split air conditioning system, when in refrigeration operation, the action of the electronic valve 28 is triggered by detecting whether the degree of supercooling in front of the electronic expansion valve 21 meets a preset value, and the auxiliary loop M is used for supercooling the refrigerant in front of the electronic expansion valve 21, so that throttling sound is reduced and refrigerating capacity is improved; the method comprises the following steps:
s1: degree of supercooling SC before preset valveP；
S2: during the refrigeration operation, the pre-valve supercooling degree SC of the electronic expansion valve 21 of each starting indoor unit is detected, and the detected pre-valve supercooling degree SC and the preset pre-valve supercooling degree SC are comparedPComparing;
s3: when SC < SCPWhen the temperature of the main loop is higher than the preset temperature, the electronic valve is opened, the auxiliary loop is opened, and the main loop and the auxiliary loop are cooperatively refrigerated;
when SC is more than or equal to SCPAnd closing the electronic valve, closing the auxiliary loop and executing the refrigeration process of the main loop.
The refrigerant condensed from the outdoor heat exchanger 13 is a high-pressure medium-temperature refrigerant with a certain supercooling degree, but reaches the electronic expansion valve 21 of the indoor unit due to the on-way resistance loss or on-way heat lossThe degree of supercooling SC before the valve is 0, and the refrigerant state at this time is a gas-liquid two-phase state, and since the two-phase refrigerant passes through the electronic expansion valve 21, a large throttling sound is generated, and it can be found from the pressure-enthalpy diagram shown in fig. 6 that the refrigeration capacity per unit refrigerant mass flow rate is reduced due to the insufficient degree of supercooling SC before the valve. When the pre-valve supercooling degree SC is detected to be smaller than the preset pre-valve supercooling degree SCPWhen the electronic valve 28 is opened, a small amount of low-temperature low-pressure two-phase refrigerant throttled by the electronic expansion valve 21 is introduced into the sub-cooler 24 to cool the refrigerant flowing into the main loop L of the indoor unit, at this time, the refrigerant obtains a certain supercooling degree, and the refrigerant of the main loop L after heat exchange has the supercooling degree, so that the throttling sound after the refrigerant passes through the electronic expansion valve 21 is greatly reduced, and meanwhile, when the auxiliary loop M is not provided, the refrigerant firstly enters the indoor expansion valve 21, and the pre-valve supercooling degree SC of the indoor expansion valve 21 is T(2-b)-T5At this time, the refrigerating capacity of the refrigerant per unit mass flow is set to point q ═ h(4-a)-h6(ii) a After the refrigerant passes through the subcooler 24 of the present invention, the pre-valve subcooling of the electronic expansion valve 21 is increased to SC ═ T(2-b)-T3When the refrigerating capacity of the refrigerant per unit mass is q ═ h(4-a)-h4Namely, the supercooling degree is increased, the refrigerating capacity of the refrigerant with unit mass flow is improved, and the refrigerating capacity of the refrigerant with unit mass flow is indirectly improved due to the improvement of the supercooling degree in front of the valve. The refrigerant of the auxiliary loop M is heated by the refrigerant of the main loop L, is changed into a low-pressure gaseous medium-temperature refrigerant with the temperature between that of the main loop L and that of the auxiliary loop M before heat exchange, and then is converged with the refrigerant at the outlet of the heat exchanger 22 through the check valve 27, so that the superheat degree of the outlet of the heat exchanger 22 is improved, and the reliability of the unit is improved. When SC is greater than SCPAt this time, the electronic valve 28 is closed, the auxiliary circuit M is cut off, and the normal cooling process is performed.
The calculation method of the pre-valve supercooling degree SC is SC-Tpd-Tin-Δt，
Wherein, TpdThe outdoor condensing pressure corresponds to the saturation temperature,
Tinis the temperature of the refrigerant before the electronic expansion valve,
and delta t is a pipeline correction coefficient of reduced supercooling degree caused by the on-way resistance loss and heat loss of the pipeline.
Wherein, as the above-described embodiment of the present invention, the pre-set pre-valve supercooling degree SCPIs 2, SCPCan take any value between 1 and 6.
When the air conditioner is operated in heating mode, the auxiliary loop M is closed due to the existence of the check valve 27, and the refrigerant is ensured not to flow through the auxiliary loop.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims (10)

1. The utility model provides a many online air conditioning system which characterized in that: comprises that
An outdoor unit;
the indoor unit comprises a plurality of indoor units connected in parallel, wherein each indoor unit is provided with an electronic expansion valve and a heat exchanger;
it is characterized by also comprising
The electronic expansion valve, the heat exchanger and a main pipeline form a main loop, and the main pipeline is a pipeline positioned at an inlet end of the electronic expansion valve, a pipeline positioned at an outlet end of the electronic expansion valve and an inlet end of the heat exchanger, and a pipeline positioned at an inlet end of the heat exchanger;
the auxiliary loop comprises a recooler, a first auxiliary pipeline and a second auxiliary pipeline, and a small amount of refrigerant is introduced into the recooler for cooling after being throttled by the electronic expansion valve;
the first auxiliary pipeline is arranged between the outlet end of the electronic expansion valve and the inlet of the sub-cooler, and introduces the refrigerant after the electronic expansion valve into the sub-cooler for sub-cooling; one end of the second auxiliary pipeline is connected with the outlet of the recooler, and the other end of the second auxiliary pipeline is connected with the main loop at the outlet of the heat exchanger.
2. A multi-split air conditioning system as claimed in claim 1, wherein a check valve is provided on the second auxiliary line to close the auxiliary circuit when heating is performed.
3. A multi-split air conditioning system as claimed in claim 2, wherein an electronic valve is provided on the first auxiliary line to enable the start and the close of the auxiliary circuit.
4. A multi-split air conditioning system as claimed in claim 3, wherein the sub-cooler includes a spiral tube and a hollow cylindrical casing sleeved outside the spiral tube, the spiral tube is formed by improving a portion of the main pipeline in front of the electronic expansion valve, two ends of the casing are respectively connected to the first auxiliary pipeline and the second auxiliary pipeline, and the refrigerant in the casing is a post-valve refrigerant of the electronic expansion valve and used for cooling the spiral tube.
5. The multi-split air conditioning system as claimed in claim 4, wherein the sleeve is spirally wound outside the spiral tube in a spiral shape, and the sleeve is a part of the first/second auxiliary ducts.
6. The multi-split air conditioning system as claimed in claim 1, wherein the outdoor unit comprises a liquid storage tank, a compressor, an outdoor heat exchanger, and an outdoor electronic expansion valve connected in sequence.
7. A multi-split air conditioning system as claimed in claim 6, wherein a four-way valve is connected between the compressor and the outdoor heat exchanger, and the four-way valve is further connected between the compressor and the liquid storage tank, and between the compressor and the indoor unit, and transmits the refrigerant passing through the compressor among the liquid storage tank, the outdoor heat exchanger, and the indoor unit.
8. A method for reducing noise of a multi-split air conditioning system, according to any of claims 1 to 6, wherein an electronic valve is provided on the first auxiliary line to enable the auxiliary circuit to be started and closed, the method comprising the steps of:
s1: degree of supercooling SC before preset valveP；
S2: during the refrigeration operation, the pre-valve supercooling degree SC of the electronic expansion valve 21 of each starting indoor unit is detected, and the detected pre-valve supercooling degree SC and the preset pre-valve supercooling degree SC are comparedPComparing;
s3: when SC < SCPWhen the temperature of the main loop is higher than the preset temperature, the electronic valve is opened, the auxiliary loop is opened, and the main loop and the auxiliary loop are cooperatively refrigerated;
when SC is more than or equal to SCPAnd closing the electronic valve, closing the auxiliary loop and executing the refrigeration process of the main loop.
9. The method for reducing noise of a multi-split air conditioning system as claimed in claim 8, wherein the calculation method of SC is SC-Tpd-Tin-Δt，
Wherein, TpdThe outdoor condensing pressure corresponds to the saturation temperature,
Tinis the temperature of the refrigerant before the electronic expansion valve,
and delta t is a pipeline correction coefficient of reduced supercooling degree caused by the on-way resistance loss and heat loss of the pipeline.
10. A method for reducing noise of a multi-split air conditioning system as set forth in claim 9, wherein the SCPIs 1 to 6.
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CN112228972B (en) * 2020-10-21 2022-04-19 青岛海信日立空调系统有限公司 Multi-split air conditioning system
CN112833472A (en) * 2021-01-25 2021-05-25 青岛腾远设计事务所有限公司 Multi-split air conditioning system with energy recovery indoor unit
CN113218035B (en) * 2021-05-14 2022-04-22 宁波奥克斯电气股份有限公司 Control method for multi-split oil return noise reduction, storage medium and multi-split air conditioner
CN114413404B (en) * 2021-12-20 2023-05-26 青岛海尔空调电子有限公司 Method and device for reducing noise of air conditioner refrigerant, air conditioner and storage medium
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CN115614947A (en) * 2022-10-14 2023-01-17 青岛海尔空调电子有限公司 Noise reduction method and device for air conditioner refrigerant throttling sound and air conditioner

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