EP3855094A1 - Cooling and heating switching device for variable refrigerant flow system capable of heat recovery, variable refrigerant flow system, and control method - Google Patents
Cooling and heating switching device for variable refrigerant flow system capable of heat recovery, variable refrigerant flow system, and control method Download PDFInfo
- Publication number
- EP3855094A1 EP3855094A1 EP19861762.3A EP19861762A EP3855094A1 EP 3855094 A1 EP3855094 A1 EP 3855094A1 EP 19861762 A EP19861762 A EP 19861762A EP 3855094 A1 EP3855094 A1 EP 3855094A1
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- EP
- European Patent Office
- Prior art keywords
- pipe
- cooling
- branch
- liquid
- subcooler
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Classifications
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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
- 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
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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
- 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
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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
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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
- F25B41/00—Fluid-circulation arrangements
- F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
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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
- F25B41/00—Fluid-circulation arrangements
- F25B41/30—Expansion means; Dispositions thereof
- F25B41/31—Expansion valves
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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
- F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
- F25B2313/007—Compression machines, plants or systems with reversible cycle not otherwise provided for three pipes connecting the outdoor side to the indoor side with multiple indoor units
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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
- F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
- F25B2313/023—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units
- F25B2313/0231—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units with simultaneous cooling and heating
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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
- F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
- F25B2313/023—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units
- F25B2313/0233—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units in parallel arrangements
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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
- F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
- F25B2400/13—Economisers
Definitions
- the present invention belongs to the technical field of air conditioning, and in particular to a cooling-heating switching device for heat-recovery multi-split air-conditioning system, a heat-recovery multi-split air conditioning system and a control method.
- the heat-recovery multi-split air conditioning system has gained popularity in the market and sales are increasing year by year.
- the majority of the heat-recovery multi-split air conditioning system of the prior art has a flow of refrigerant with three pipes: in the simultaneous cooling/heating operation, refrigerant flowing into those indoor units in cooling operation may make a loud flowing sound because of insufficient subcooling as refrigerant flowing out of the liquid pipe from those indoor units in heating operation.
- refrigerant flowing into those indoor units in cooling operation may make a loud flowing sound because of insufficient subcooling as refrigerant flowing out of the liquid pipe from those indoor units in heating operation.
- it is easy to cause an uneven distribution of refrigerant among the indoor units in cooling operation it is easy to cause an uneven distribution of refrigerant among the indoor units in cooling operation, and the performances of part of the indoor units in cooling operation become progressively worse.
- the present invention provides a cooling-heating switching device for heat-recovery multi-split air conditioning system aiming at solving the problem of loud flowing sound, which is compact in structure and low in cost.
- the present invention adopts the following technical solutions.
- a cooling-heating switching device for heat-recovery multi-split air conditioning system includes: a main liquid pipe, a high-pressure gas pipe, a plurality of high-pressure branch pipes, a low-pressure gas pipe, a plurality of low-pressure branch pipes, a subcooler, a plurality of branch liquid pipes and a plurality of liquid distribution pipes; wherein the high-pressure gas pipe is connected to a high-pressure gas pipe of an outdoor unit and the low-pressure gas pipe is connected to a low-pressure gas pipe of the outdoor unit, and the main liquid pipe is connected to the liquid pipe of the outdoor unit; one end of each high-pressure branch pipe is connected to one end of each low-pressure branch pipe in a one-to-one correspondence forming a plurality of connection nodes; the connection nodes are connected to gas pipes of indoor units in a one-to-one correspondence; the other end of each high-pressure branch pipe is connected to the high-pressure gas pipe, and each high-pressure branch pipe is provided with a valve; the other end of each low
- valves on the high-pressure branch pipes are driven by a main control board of the cooling-heating switching device.
- valves on the low-pressure branch pipes are driven by a main control board of the cooling-heating switching device.
- valves provided on the branch liquid pipes are one-way valves, wherein an inlet of each one-way valve is respectively connected to the main liquid pipe and an outlet of each one-way valve is connected to a liquid pipe of an indoor unit' or, the valves provided on the branch liquid pipes are solenoid valves or electronic expansion valves which are driven by a main control board of the cooling-heating switching device.
- valves provided on the liquid distribution pipes are one-way valves, wherein an inlet of each one-way valve is respectively connected to a liquid pipe of an indoor unit and an outlet of each one-way valve is respectively connected to the main pipe inlet of the subcooler; or, the valves provided on the liquid distribution pipes are solenoid valves or electronic expansion valves, which are driven by a main control board of the cooling-heating switching device.
- the throttling structure is an electronic expansion valve, a thermal expansion valve, a solenoid valve and capillary tube connected in series which is driven by a main control board of the cooling-heating switching device.
- a temperature sensor is provided at a main pipe outlet of the subcooler.
- another aspect of the present invention also provides a heat-recovery multi-split air conditioning system including an outdoor unit, a plurality of indoor units and the cooling-heating switching device.
- another aspect of the present invention also provides a control method for the cooling-heating switching device including:
- the adjustment of the throttling structure according to the difference ⁇ T specifically includes:
- the advantages and positive effects of the present invention are: the cooling-heating switching device, the heat-recovery multi-split air conditioning system and the control method disclosed by the present invention provides an effective solution to the loud flowing sound problem of the heat-recovery multi-split air conditioning system in the prior art by means of the incorporation of the subcooler and the throttling structure, with which liquid refrigerant in the main liquid pipe 1 could reach a better subcooling degree so that noise will not occur as flowing into the indoor units, and liquid refrigerant in the main liquid pipe 1 will not vaporize to flash gas due to insufficient subcooling so the problem of unbalanced refrigerant distribution between indoor units working in cooling mode could be prevented.
- the cooling-heating switching device is compact in structure, low in cost and easy to install by merely adding one subcooler and one throttling structure.
- a heat-recovery multi-split air conditioning system includes an outdoor unit, a plurality of indoor units and a cooling-heating switching device for heat-recovery multi-split air conditioning system.
- the cooling-heating switching device for heat-recovery multi-split air conditioning system includes a main liquid pipe 1, a high-pressure gas pipe 3, a plurality of high-pressure branch pipes, a low-pressure gas pipe 2, a plurality of low-pressure branch pipes, a subcooler 4, a plurality of branch liquid pipes, a plurality of liquid distribution pipes, etc., as shown in Fig. 1 ; wherein the high-pressure gas pipe 3 is connected to a high-pressure gas pipe of the outdoor unit and the low-pressure gas pipe 2 is connected to a low-pressure gas pipe of the outdoor unit, and the main liquid pipe 1 is connected to the liquid pipe of the outdoor unit.
- each high-pressure branch pipe is connected to one end of each low-pressure branch pipe in a one-to-one correspondence so as to form a plurality of connection nodes.
- the connection nodes are connected to gas pipes of indoor units in a one-to-one correspondence.
- each high-pressure branch pipe is connected to the high-pressure gas pipe 3, and each high-pressure branch pipe is provided with a valve that opens and closes to control the flow in the high-pressure branch pipe.
- each low-pressure branch pipe is connected to the low-pressure gas pipe 2, and each low-pressure branch pipe is provided with a valve that opens and closes to control the flow in the low-pressure branch pipe.
- each branch liquid pipe is connected to one end of each liquid distribution pipe in a one-to-one correspondence so as to form a plurality of connection points, and the plurality of connection points are connected to the liquid pipe of each indoor unit in a one-to-one correspondence.
- each branch liquid pipe is respectively connected to the main liquid pipe 1, and each branch liquid pipe is provided with a valve that opens and closes to control the flow in the branch liquid pipe.
- each liquid distribution pipe is respectively connected to a main pipe inlet A of the subcooler 4, and each liquid distribution pipe is provided with a valve that opens and closes to control the flow in the liquid distribution pipe.
- the subcooler 4 includes a tank body opened with the main pipe inlet A, a main pipe outlet B, a cooling branch pipe inlet C and a cooling branch pipe outlet D; wherein the main pipe inlet A is connected to the main pipe outlet B via a main pipe, the cooling branch pipe inlet C is connected to the cooling branch pipe outlet D via a cooling branch pipe.
- Refrigerant flowing into the subcooler 4 via the main pipe inlet A exchanges heat with refrigerant flowing into the subcooler 4 via the cooling branch pipe inlet C, which also could be regarded as a heat exchange between the main pipe and the cooling branch pipe.
- the main pipe outlet B of the subcooler 4 is connected to the main liquid pipe 1; the cooling branch pipe inlet C of the subcooler 4 is connected to the main pipe outlet B of the subcooler 4, a throttle structure VSC is disposed in a connection pipe between the cooling branch pipe inlet C of the subcooler 4 and the main pipe outlet B of the subcooler 4; the cooling branch pipe outlet D of the subcooler 4 is connected to the low-pressure gas pipe 2.
- the multi-connection includes n indoor units: indoor unit 1, indoor unit 2,..., indoor unit n-1, indoor unit n, as shown in FIG. 1 .
- a valve VHI1 is provided on a high-pressure branch pipe connecting the high-pressure gas pipe 3 to a gas pipe of the indoor unit 1.
- a valve VLO1 is provided on a low-pressure branch pipe connecting the low-pressure gas pipe 2 to the gas pipe of the indoor unit 1.
- a valve V11 is provided on a branch liquid pipe connecting the main liquid pipe 1 to a liquid pipe of the indoor unit 1.
- a valve V12 is provided on a liquid distribution pipe connecting the main pipe inlet A of the subcooler 4 to the liquid pipe of the indoor unit 1.
- a valve VHI2 is provided on a high-pressure branch pipe connecting the high-pressure gas pipe 3 to a gas pipe of the indoor unit 2.
- a valve VLO2 is provided on a low-pressure branch pipe connecting the low-pressure gas pipe 2 to the gas pipe of the indoor unit 2.
- a valve V21 is provided on a branch liquid pipe connecting the main liquid pipe 1 to a liquid pipe of the indoor unit 2.
- a valve V22 is provided on a liquid distribution pipe connecting the main pipe inlet A of the subcooler 4 to the liquid pipe of the indoor unit 2.
- a valve VHIn is provided on a high-pressure branch pipe connecting the high-pressure gas pipe 3 to a gas pipe of the indoor unit n.
- a valve VLOn is provided on a low-pressure branch pipe connecting the low-pressure gas pipe 2 to the gas pipe of the indoor unit n.
- a valve Vnl is provided on a branch liquid pipe connecting the main liquid pipe 1 to a liquid pipe of the indoor unit n.
- a valve Vn2 is provided on a liquid distribution pipe connecting the main pipe inlet A of the subcooler 4 to the liquid pipe of the indoor unit n.
- indoor unit 1 and outdoor unit 2 operate in heating mode while indoor unit 3 and indoor unit n operate in cooling mode.
- valves VHI3 and VHIn on the high-pressure branch pipes close, the valves VLO3 and VLOn on the low-pressure branch pipes open, the valves V31 and Vnl on the branch liquid pipes open and the valves V32 and Vn2 on the liquid distribution pipes close.
- a working process includes: the outdoor unit discharges high-temperature and high-pressure refrigerant gas to the high-pressure gas pipe 3.
- the refrigerant gas in the high-pressure gas pipe 3 respectively enters the indoor unit 1 and the indoor unit 2 through the valves VHI1 and VHI2.
- Condensed refrigerant from the indoor unit 1 and the indoor unit 2 which are in heating modes flows to the main pipe inlet A of the subcooler 4 through the valves V12 and V22, enters into the subcooler 4, and then flows out through the main pipe outlet B.
- Refrigerant flowing out from the subcooler 4 is divided into two flows, one passage flows to the main liquid pipe 1 and the other passage flows to the cooling branch inlet C through the throttling structure in which pressure is reduced, enters into the subcooler 4, and then flows out through the cooling branch outlet D, then enters into the low-pressure gas pipe 2.
- the refrigerant that enters the subcooler 4 through the main pipe inlet A exchanges heat with the refrigerant that enters the subcooler 4 through the cooling branch inlet C.
- the temperature of the refrigerant that enters the subcooler 4 through the main pipe inlet A decreases while the temperature of the refrigerant that enters the subcooler 4 through the cooling branch inlet C increases.
- the throttling structure control the subcooling of the refrigerant flowing out of the main pipe outlet B of the subcooler 4 to a set subcooling degree, that is to say, the liquid refrigerant in the main liquid pipe 1 has a required degree of subcooling.
- the liquid refrigerant collected in the main liquid pipe 1 is evenly distributed to each refrigerating indoor unit working in cooling mode. A part of the liquid refrigerant enters into the indoor unit n through the valve Vn1, and the other part of the liquid refrigerant enters into the indoor unit 3 through the valve V31. Evaporated gas refrigerant from the indoor unit 3 and from the indoor unit n in cooling mode flows to the low-pressure gas pipe 2 through the valves VLO3 and VLOn, and then flows back to the outdoor unit.
- the cooling-heating switching device for heat-recovery multi-split air conditioning system and the heat-recovery multi-split air conditioning system using the same disclosed by the present embodiment provides an effective solution to the loud flowing sound problem of the heat-recovery multi-split air conditioning system in the prior art by means of the incorporation of the subcooler and the throttling structure, with which liquid refrigerant in the main liquid pipe 1 could reach a required subcooling degree so that noise will not occur as flowing into the indoor units, and liquid refrigerant in the main liquid pipe 1 will not vaporize to flash gas due to insufficient subcooling so the problem of unbalanced refrigerant distribution between indoor units working in cooling mode could be prevented.
- the cooling-heating switching device is compact in structure, low in cost and easy to install by merely adding one subcooler and one throttling structure.
- the cooling-heating switching device for heat-recovery multi-split air conditioning system provided by the present invention solves the problems of loud flowing sound of refrigerant and unbalanced refrigerant distribution among indoor units working in cooling mode of the heat-recovery multi-split air conditioning system having a flow of refrigerant with three pipes.
- the valves provided on the high-pressure branch pipes are solenoid valves, electronic expansion valves, four-way valves, three-way valves, and the like capable of opening and closing to control the flow, which are driven by a main control board of the cooling-heating switching device for heat-recovery multi-split air conditioning system.
- the valves provided on the high-pressure branch pipes are electronic expansion valves which are easy to control and stable in performance.
- the valves provided on the low-pressure branch pipes are solenoid valves, electronic expansion valves, four-way valves, three-way valves, and the like capable of opening and closing to control the flow, which are driven by the main control board of the cooling-heating switching device for heat-recovery multi-split air conditioning system.
- the valves provided on the low-pressure branch pipes are electronic expansion valves which are easy to control and stable in performance.
- the valves provided on the branch liquid pipes are one-way valves, wherein an inlet of each one-way valve is respectively connected to the main liquid pipe 1 and an outlet of each one-way valve is correspondingly connected to a liquid pipe of an indoor unit; the one-way valve is simple and no further control is required.
- the valves provided on the branch liquid pipes could be solenoid valves or electronic expansion valves, which are driven by the main control board of the cooling-heating switching device for heat-recovery multi-split air conditioning system, being easy to control and stable in performance.
- the valves provided on the liquid distribution pipes are one-way valves, wherein an inlet of each one-way valve is respectively connected to a liquid pipe of an indoor unit and an outlet of each one-way valve is respectively connected to the main pipe inlet A of the subcooler 4; the one-way valve is simple and no further control is required.
- the valves provided on the liquid distribution pipes could be solenoid valves or electronic expansion valves, which are driven by the main control board of the cooling-heating switching device for heat-recovery multi-split air conditioning system, being easy to control and stable in performance.
- the throttling structure is an electronic expansion valve, a thermal expansion valve, a solenoid valve and capillary tube connected in series, and the like to allow restricted flow of the refrigerant, which is driven by the main control board of the cooling-heating switching device for heat-recovery multi-split air conditioning system to control the restricted flow of the refrigerant, being simple in structure, easy to use and install.
- a temperature sensor is provided at the main pipe outlet B of the subcooler 4 for the detection of the temperature at the main pipe outlet B.
- a multi-split air conditioning system includes the indoor unit 1 and the indoor unit 2, as shown in Fig.2 , wherein the indoor unit 1 working in heating mode and the indoor unit 2 working in cooling mode, the valve VHI1 opens, the valve VLO1 closes, the valve VHI2 closes and the valve VLO2 opens; valves V11, V12, V21, V22 are one-way valves.
- the outdoor unit discharges high-temperature and high-pressure gas refrigerant to the high-pressure gas pipe 3.
- the high-temperature and high-pressure gas refrigerant in the high-pressure gas pipe 3 enters into the indoor unit 1 through the valve VHI1.
- Condensed liquid refrigerant from the indoor unit 1 working in heating mode flows to the main pipe inlet A through the way valve V12, enters the subcooler 4 and flows out of the subcooler 4 through the main pipe outlet B.
- Refrigerant flowing out from the subcooler 4 is divided into two flows, one passage flows to the main liquid pipe 1 and the other passage flows to cooling branch inlet C through the throttling structure in which pressure is reduced, enters into the subcooler 4, and then flows out through the cooling branch outlet D, then enters into the low-pressure gas pipe 2.
- a part of liquid refrigerant in the main liquid pipe 1 flows into the indoor unit 2 working in cooling mode through the one-way valve V21.
- Evaporated gas refrigerant from the indoor unit 2 flows to the low-pressure gas pipe 2 through the valve VLO2 and then back to the outdoor unit.
- the refrigerant suffers pipe friction loss as flowing along the pipes so its pressure gradually decreases ⁇ T different positions of the pipes as flowing through, indicating as P4>P2>P1>P3. If a pressure of the refrigerant at the inlet of the one-way valve V11 is less than a pressure of the refrigerant at the outlet of the one-way valve V11, or a pressure of the refrigerant at the inlet of the one-way valve V12 is less than a pressure of the refrigerant at the outlet of the one-way valve V12, the one-way valve V11 and one-way valve V12 close; if a pressure of the refrigerant at the inlet of the one-way valve V11 is greater than a pressure of the refrigerant at the outlet of the one-way valve V11, or a pressure of the refrigerant at the inlet of the one-way valve V12 is greater than a pressure of the refrigerant at the outlet of the one-way valve V12, the one-way valve V
- liquid refrigerant from the liquid pipe of the indoor unit 1 only could flow into the subcooler 4 through the one-way valve V12.
- the refrigerant reaches to a required subcooling degree by the control the throttling structure VSC of the subcooler 4 and flows into the main liquid pipe 1.
- another aspect of the present invention is to provide a control method of the cooling-heating switching device for heat-recovery multi-split air conditioning system, the controlling method includes following steps, which is shown in Fig. 3 .
- Step S1 obtaining a saturation temperature CT corresponding to an outdoor unit high pressure.
- the outdoor unit high pressure is a pressure at a gas discharge port of a compressor in the outdoor unit. Based on the outdoor unit high pressure, a corresponding saturation temperature CT could be obtained.
- Step S2 obtaining a temperature TLq at a main pipe outlet of a subcooler.
- the temperature TLq could be obtained by a temperature sensor installed at main pipe outlet.
- the target subcooling degree ST is a preset target value. When the refrigerant in the main liquid pipe reaches the target subcooling degree ST, noise will not occur as flowing into the indoor units.
- Step S5 Adjusting the throttling structure according to the difference ⁇ T, and returning to step S1.
- the adjusting the throttling structure according to the difference ⁇ T specifically includes: If the difference ⁇ T> 0, adjusting the throttling structure to reduce the amount of refrigerant flowing in a connection pipe between the cooling branch inlet of the subcooler and the main pipe outlet of the subcooler, so as to increase the temperature TLq at the main pipe outlet preventing the subcooling degree too low to affect the refrigerant flow in the main liquid pipe.
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- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Compression-Type Refrigeration Machines With Reversible Cycles (AREA)
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Abstract
Description
- The present invention belongs to the technical field of air conditioning, and in particular to a cooling-heating switching device for heat-recovery multi-split air-conditioning system, a heat-recovery multi-split air conditioning system and a control method.
- With excellent energy-saving performance and flexible and comfortable using experience, the heat-recovery multi-split air conditioning system has gained popularity in the market and sales are increasing year by year. The majority of the heat-recovery multi-split air conditioning system of the prior art has a flow of refrigerant with three pipes: in the simultaneous cooling/heating operation, refrigerant flowing into those indoor units in cooling operation may make a loud flowing sound because of insufficient subcooling as refrigerant flowing out of the liquid pipe from those indoor units in heating operation. In addition, on condition that there is height difference between the indoor units in cooling operation, it is easy to cause an uneven distribution of refrigerant among the indoor units in cooling operation, and the performances of part of the indoor units in cooling operation become progressively worse.
- The present invention provides a cooling-heating switching device for heat-recovery multi-split air conditioning system aiming at solving the problem of loud flowing sound, which is compact in structure and low in cost.
- To solve the above technical problems, the present invention adopts the following technical solutions.
- A cooling-heating switching device for heat-recovery multi-split air conditioning system includes: a main liquid pipe, a high-pressure gas pipe, a plurality of high-pressure branch pipes, a low-pressure gas pipe, a plurality of low-pressure branch pipes, a subcooler, a plurality of branch liquid pipes and a plurality of liquid distribution pipes; wherein the high-pressure gas pipe is connected to a high-pressure gas pipe of an outdoor unit and the low-pressure gas pipe is connected to a low-pressure gas pipe of the outdoor unit, and the main liquid pipe is connected to the liquid pipe of the outdoor unit; one end of each high-pressure branch pipe is connected to one end of each low-pressure branch pipe in a one-to-one correspondence forming a plurality of connection nodes; the connection nodes are connected to gas pipes of indoor units in a one-to-one correspondence; the other end of each high-pressure branch pipe is connected to the high-pressure gas pipe, and each high-pressure branch pipe is provided with a valve; the other end of each low-pressure branch pipe is connected to the low-pressure gas pipe, and each low-pressure branch pipe is provided with a valve; one end of each branch liquid pipe is connected to one end of each liquid distribution pipe in a one-to-one correspondence so as to form a plurality of connection points, and the plurality of connection points are connected to the liquid pipe of each indoor unit in a one-to-one correspondence; the other end of each liquid distribution pipe is respectively connected to a main pipe inlet of the subcooler, and each liquid distribution pipe is provided with a valve; and a main pipe outlet of the subcooler is connected to the main liquid pipe; a cooling branch pipe inlet of the subcooler is connected to the main pipe outlet of the subcooler, a throttle structure VSC is disposed in the connection pipe between the cooling branch pipe inlet and the main pipe outlet of the subcooler; a cooling branch pipe outlet of the subcooler is connected to the low-pressure gas pipe.
- Further, the valves on the high-pressure branch pipes are driven by a main control board of the cooling-heating switching device.
- Further, the valves on the low-pressure branch pipes are driven by a main control board of the cooling-heating switching device.
- Further, the valves provided on the branch liquid pipes are one-way valves, wherein an inlet of each one-way valve is respectively connected to the main liquid pipe and an outlet of each one-way valve is connected to a liquid pipe of an indoor unit' or, the valves provided on the branch liquid pipes are solenoid valves or electronic expansion valves which are driven by a main control board of the cooling-heating switching device.
- Further, the valves provided on the liquid distribution pipes are one-way valves, wherein an inlet of each one-way valve is respectively connected to a liquid pipe of an indoor unit and an outlet of each one-way valve is respectively connected to the main pipe inlet of the subcooler; or, the valves provided on the liquid distribution pipes are solenoid valves or electronic expansion valves, which are driven by a main control board of the cooling-heating switching device.
- Further, the throttling structure is an electronic expansion valve, a thermal expansion valve, a solenoid valve and capillary tube connected in series which is driven by a main control board of the cooling-heating switching device.
- Further, a temperature sensor is provided at a main pipe outlet of the subcooler.
- Based on the design of the above-mentioned the cooling-heating switching device for heat-recovery multi-split air conditioning system, another aspect of the present invention also provides a heat-recovery multi-split air conditioning system including an outdoor unit, a plurality of indoor units and the cooling-heating switching device.
- Based on the design of the above-mentioned the cooling-heating switching device for heat-recovery multi-split air conditioning system, another aspect of the present invention also provides a control method for the cooling-heating switching device including:
- (1) obtaining a saturation temperature CT corresponding to an outdoor unit high pressure;
- (2) obtaining a temperature TLq at a main pipe outlet of a subcooler;
- (3) calculating an actual subcooling degree SC, SC=CT-TLq;
- (4) calculating a difference between a target subcooling degree ST and the actual subcooling degree SC, ΔT = ST-SC;
- (5) Adjusting the throttling structure according to the difference ΔT, and returning to step (1).
- Further, the adjustment of the throttling structure according to the difference ΔT specifically includes:
- if the difference ΔT> 0, adjusting the throttling structure to reduce the amount of refrigerant flowing in a connection pipe between the cooling branch inlet of the subcooler and the main pipe outlet of the subcooler;
- if the difference ΔT <0, adjusting the throttling structure to increase the amount of refrigerant flowing in a connection pipe between the cooling branch inlet of the subcooler and the main pipe outlet of the subcooler
- Compared with the prior art, the advantages and positive effects of the present invention are: the cooling-heating switching device, the heat-recovery multi-split air conditioning system and the control method disclosed by the present invention provides an effective solution to the loud flowing sound problem of the heat-recovery multi-split air conditioning system in the prior art by means of the incorporation of the subcooler and the throttling structure, with which liquid refrigerant in the main
liquid pipe 1 could reach a better subcooling degree so that noise will not occur as flowing into the indoor units, and liquid refrigerant in the mainliquid pipe 1 will not vaporize to flash gas due to insufficient subcooling so the problem of unbalanced refrigerant distribution between indoor units working in cooling mode could be prevented. The cooling-heating switching device is compact in structure, low in cost and easy to install by merely adding one subcooler and one throttling structure. - After reading the specific embodiments of the present invention in conjunction with the accompanying drawings, other features and advantages of the present invention will become clearer.
-
-
Fig. 1 is a schematic structural diagram of a cooling-heating switching device for heat-recovery multi-split air conditioning system according to one aspect of the present invention; -
Fig. 2 is a schematic structural diagram of a cooling-heating switching device for heat-recovery multi-split air conditioning system according to another aspect of the present invention; -
Fig. 3 is a flow chart showing a control method of a cooling-heating switching device for heat-recovery multi-split air conditioning system according to another aspect of the present invention; -
- 1. Main Liquid Pipe;
- 2. Low-pressure Gas Pipe;
- 3. High-pressure Gas Pipe;
- 4. Subcooler.
- In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.
- A heat-recovery multi-split air conditioning system includes an outdoor unit, a plurality of indoor units and a cooling-heating switching device for heat-recovery multi-split air conditioning system.
- The cooling-heating switching device for heat-recovery multi-split air conditioning system includes a main
liquid pipe 1, a high-pressure gas pipe 3, a plurality of high-pressure branch pipes, a low-pressure gas pipe 2, a plurality of low-pressure branch pipes, asubcooler 4, a plurality of branch liquid pipes, a plurality of liquid distribution pipes, etc., as shown inFig. 1 ; wherein the high-pressure gas pipe 3 is connected to a high-pressure gas pipe of the outdoor unit and the low-pressure gas pipe 2 is connected to a low-pressure gas pipe of the outdoor unit, and the mainliquid pipe 1 is connected to the liquid pipe of the outdoor unit. - One end of each high-pressure branch pipe is connected to one end of each low-pressure branch pipe in a one-to-one correspondence so as to form a plurality of connection nodes. The connection nodes are connected to gas pipes of indoor units in a one-to-one correspondence.
- The other end of each high-pressure branch pipe is connected to the high-
pressure gas pipe 3, and each high-pressure branch pipe is provided with a valve that opens and closes to control the flow in the high-pressure branch pipe. - The other end of each low-pressure branch pipe is connected to the low-
pressure gas pipe 2, and each low-pressure branch pipe is provided with a valve that opens and closes to control the flow in the low-pressure branch pipe. - One end of each branch liquid pipe is connected to one end of each liquid distribution pipe in a one-to-one correspondence so as to form a plurality of connection points, and the plurality of connection points are connected to the liquid pipe of each indoor unit in a one-to-one correspondence.
- The other end of each branch liquid pipe is respectively connected to the main
liquid pipe 1, and each branch liquid pipe is provided with a valve that opens and closes to control the flow in the branch liquid pipe. - The other end of each liquid distribution pipe is respectively connected to a main pipe inlet A of the
subcooler 4, and each liquid distribution pipe is provided with a valve that opens and closes to control the flow in the liquid distribution pipe. - The
subcooler 4 includes a tank body opened with the main pipe inlet A, a main pipe outlet B, a cooling branch pipe inlet C and a cooling branch pipe outlet D; wherein the main pipe inlet A is connected to the main pipe outlet B via a main pipe, the cooling branch pipe inlet C is connected to the cooling branch pipe outlet D via a cooling branch pipe. Refrigerant flowing into thesubcooler 4 via the main pipe inlet A exchanges heat with refrigerant flowing into thesubcooler 4 via the cooling branch pipe inlet C, which also could be regarded as a heat exchange between the main pipe and the cooling branch pipe. - The main pipe outlet B of the
subcooler 4 is connected to the mainliquid pipe 1; the cooling branch pipe inlet C of thesubcooler 4 is connected to the main pipe outlet B of thesubcooler 4, a throttle structure VSC is disposed in a connection pipe between the cooling branch pipe inlet C of thesubcooler 4 and the main pipe outlet B of thesubcooler 4; the cooling branch pipe outlet D of thesubcooler 4 is connected to the low-pressure gas pipe 2. - It is assumed that the multi-connection includes n indoor units:
indoor unit 1,indoor unit 2,..., indoor unit n-1, indoor unit n, as shown inFIG. 1 . - A valve VHI1 is provided on a high-pressure branch pipe connecting the high-
pressure gas pipe 3 to a gas pipe of theindoor unit 1. - A valve VLO1 is provided on a low-pressure branch pipe connecting the low-
pressure gas pipe 2 to the gas pipe of theindoor unit 1. - A valve V11 is provided on a branch liquid pipe connecting the main
liquid pipe 1 to a liquid pipe of theindoor unit 1. - A valve V12 is provided on a liquid distribution pipe connecting the main pipe inlet A of the
subcooler 4 to the liquid pipe of theindoor unit 1. - A valve VHI2 is provided on a high-pressure branch pipe connecting the high-
pressure gas pipe 3 to a gas pipe of theindoor unit 2. - A valve VLO2 is provided on a low-pressure branch pipe connecting the low-
pressure gas pipe 2 to the gas pipe of theindoor unit 2. - A valve V21 is provided on a branch liquid pipe connecting the main
liquid pipe 1 to a liquid pipe of theindoor unit 2. - A valve V22 is provided on a liquid distribution pipe connecting the main pipe inlet A of the
subcooler 4 to the liquid pipe of theindoor unit 2. - A valve VHIn is provided on a high-pressure branch pipe connecting the high-
pressure gas pipe 3 to a gas pipe of the indoor unit n. - A valve VLOn is provided on a low-pressure branch pipe connecting the low-
pressure gas pipe 2 to the gas pipe of the indoor unit n. - A valve Vnl is provided on a branch liquid pipe connecting the main
liquid pipe 1 to a liquid pipe of the indoor unit n. - A valve Vn2 is provided on a liquid distribution pipe connecting the main pipe inlet A of the
subcooler 4 to the liquid pipe of the indoor unit n. - As an example, it assumes that the
indoor unit 1 andoutdoor unit 2 operate in heating mode whileindoor unit 3 and indoor unit n operate in cooling mode. - The valves VHI1 and VHI2 on the high-pressure branch pipes open, the valves VLO1 and VLO2 on the low-pressure branch pipes close, the valves VII and V21 on the branch liquid pipes close and the valves V12 and V22 on the liquid distribution pipes open.
- The valves VHI3 and VHIn on the high-pressure branch pipes close, the valves VLO3 and VLOn on the low-pressure branch pipes open, the valves V31 and Vnl on the branch liquid pipes open and the valves V32 and Vn2 on the liquid distribution pipes close.
- A working process includes: the outdoor unit discharges high-temperature and high-pressure refrigerant gas to the high-
pressure gas pipe 3. The refrigerant gas in the high-pressure gas pipe 3 respectively enters theindoor unit 1 and theindoor unit 2 through the valves VHI1 and VHI2. Condensed refrigerant from theindoor unit 1 and theindoor unit 2 which are in heating modes flows to the main pipe inlet A of thesubcooler 4 through the valves V12 and V22, enters into thesubcooler 4, and then flows out through the main pipe outlet B. Refrigerant flowing out from thesubcooler 4 is divided into two flows, one passage flows to the mainliquid pipe 1 and the other passage flows to the cooling branch inlet C through the throttling structure in which pressure is reduced, enters into thesubcooler 4, and then flows out through the cooling branch outlet D, then enters into the low-pressure gas pipe 2. The refrigerant that enters thesubcooler 4 through the main pipe inlet A exchanges heat with the refrigerant that enters thesubcooler 4 through the cooling branch inlet C. The temperature of the refrigerant that enters thesubcooler 4 through the main pipe inlet A decreases while the temperature of the refrigerant that enters thesubcooler 4 through the cooling branch inlet C increases. The throttling structure control the subcooling of the refrigerant flowing out of the main pipe outlet B of thesubcooler 4 to a set subcooling degree, that is to say, the liquid refrigerant in the mainliquid pipe 1 has a required degree of subcooling. The liquid refrigerant collected in the mainliquid pipe 1 is evenly distributed to each refrigerating indoor unit working in cooling mode. A part of the liquid refrigerant enters into the indoor unit n through the valve Vn1, and the other part of the liquid refrigerant enters into theindoor unit 3 through the valve V31. Evaporated gas refrigerant from theindoor unit 3 and from the indoor unit n in cooling mode flows to the low-pressure gas pipe 2 through the valves VLO3 and VLOn, and then flows back to the outdoor unit. - The cooling-heating switching device for heat-recovery multi-split air conditioning system and the heat-recovery multi-split air conditioning system using the same disclosed by the present embodiment provides an effective solution to the loud flowing sound problem of the heat-recovery multi-split air conditioning system in the prior art by means of the incorporation of the subcooler and the throttling structure, with which liquid refrigerant in the main
liquid pipe 1 could reach a required subcooling degree so that noise will not occur as flowing into the indoor units, and liquid refrigerant in the mainliquid pipe 1 will not vaporize to flash gas due to insufficient subcooling so the problem of unbalanced refrigerant distribution between indoor units working in cooling mode could be prevented. The cooling-heating switching device is compact in structure, low in cost and easy to install by merely adding one subcooler and one throttling structure. - The cooling-heating switching device for heat-recovery multi-split air conditioning system provided by the present invention solves the problems of loud flowing sound of refrigerant and unbalanced refrigerant distribution among indoor units working in cooling mode of the heat-recovery multi-split air conditioning system having a flow of refrigerant with three pipes.
- In the present invention, the valves provided on the high-pressure branch pipes are solenoid valves, electronic expansion valves, four-way valves, three-way valves, and the like capable of opening and closing to control the flow, which are driven by a main control board of the cooling-heating switching device for heat-recovery multi-split air conditioning system. Preferably, the valves provided on the high-pressure branch pipes are electronic expansion valves which are easy to control and stable in performance. In the present invention, the valves provided on the low-pressure branch pipes are solenoid valves, electronic expansion valves, four-way valves, three-way valves, and the like capable of opening and closing to control the flow, which are driven by the main control board of the cooling-heating switching device for heat-recovery multi-split air conditioning system. Preferably, the valves provided on the low-pressure branch pipes are electronic expansion valves which are easy to control and stable in performance.
- In the present invention, the valves provided on the branch liquid pipes are one-way valves, wherein an inlet of each one-way valve is respectively connected to the main
liquid pipe 1 and an outlet of each one-way valve is correspondingly connected to a liquid pipe of an indoor unit; the one-way valve is simple and no further control is required. Alternatively, the valves provided on the branch liquid pipes could be solenoid valves or electronic expansion valves, which are driven by the main control board of the cooling-heating switching device for heat-recovery multi-split air conditioning system, being easy to control and stable in performance. - In the present invention, the valves provided on the liquid distribution pipes are one-way valves, wherein an inlet of each one-way valve is respectively connected to a liquid pipe of an indoor unit and an outlet of each one-way valve is respectively connected to the main pipe inlet A of the
subcooler 4; the one-way valve is simple and no further control is required. Alternatively, the valves provided on the liquid distribution pipes could be solenoid valves or electronic expansion valves, which are driven by the main control board of the cooling-heating switching device for heat-recovery multi-split air conditioning system, being easy to control and stable in performance. - In the present embodiment, the throttling structure is an electronic expansion valve, a thermal expansion valve, a solenoid valve and capillary tube connected in series, and the like to allow restricted flow of the refrigerant, which is driven by the main control board of the cooling-heating switching device for heat-recovery multi-split air conditioning system to control the restricted flow of the refrigerant, being simple in structure, easy to use and install.
- In the present embodiment, a temperature sensor is provided at the main pipe outlet B of the
subcooler 4 for the detection of the temperature at the main pipe outlet B. - It is assumed that a multi-split air conditioning system includes the
indoor unit 1 and theindoor unit 2, as shown inFig.2 , wherein theindoor unit 1 working in heating mode and theindoor unit 2 working in cooling mode, the valve VHI1 opens, the valve VLO1 closes, the valve VHI2 closes and the valve VLO2 opens; valves V11, V12, V21, V22 are one-way valves. - The outdoor unit discharges high-temperature and high-pressure gas refrigerant to the high-
pressure gas pipe 3. The high-temperature and high-pressure gas refrigerant in the high-pressure gas pipe 3 enters into theindoor unit 1 through the valve VHI1. Condensed liquid refrigerant from theindoor unit 1 working in heating mode flows to the main pipe inlet A through the way valve V12, enters thesubcooler 4 and flows out of thesubcooler 4 through the main pipe outlet B. Refrigerant flowing out from thesubcooler 4 is divided into two flows, one passage flows to the mainliquid pipe 1 and the other passage flows to cooling branch inlet C through the throttling structure in which pressure is reduced, enters into thesubcooler 4, and then flows out through the cooling branch outlet D, then enters into the low-pressure gas pipe 2. A part of liquid refrigerant in the mainliquid pipe 1 flows into theindoor unit 2 working in cooling mode through the one-way valve V21. Evaporated gas refrigerant from theindoor unit 2 flows to the low-pressure gas pipe 2 through the valve VLO2 and then back to the outdoor unit. - The refrigerant suffers pipe friction loss as flowing along the pipes so its pressure gradually decreases ΔT different positions of the pipes as flowing through, indicating as P4>P2>P1>P3. If a pressure of the refrigerant at the inlet of the one-way valve V11 is less than a pressure of the refrigerant at the outlet of the one-way valve V11, or a pressure of the refrigerant at the inlet of the one-way valve V12 is less than a pressure of the refrigerant at the outlet of the one-way valve V12, the one-way valve V11 and one-way valve V12 close; if a pressure of the refrigerant at the inlet of the one-way valve V11 is greater than a pressure of the refrigerant at the outlet of the one-way valve V11, or a pressure of the refrigerant at the inlet of the one-way valve V12 is greater than a pressure of the refrigerant at the outlet of the one-way valve V12, the one-way valve V11 and one-way valve V12 open. With these arrangements, liquid refrigerant from the liquid pipe of the
indoor unit 1 only could flow into thesubcooler 4 through the one-way valve V12. The refrigerant reaches to a required subcooling degree by the control the throttling structure VSC of thesubcooler 4 and flows into the mainliquid pipe 1. - Based on the design of the cooling-heating switching device for heat-recovery multi-split air conditioning system, another aspect of the present invention is to provide a control method of the cooling-heating switching device for heat-recovery multi-split air conditioning system, the controlling method includes following steps, which is shown in
Fig. 3 . - Step S1: obtaining a saturation temperature CT corresponding to an outdoor unit high pressure.
- To be specific, the outdoor unit high pressure is a pressure at a gas discharge port of a compressor in the outdoor unit. Based on the outdoor unit high pressure, a corresponding saturation temperature CT could be obtained.
- Step S2: obtaining a temperature TLq at a main pipe outlet of a subcooler.
- The temperature TLq could be obtained by a temperature sensor installed at main pipe outlet.
- Step S3: calculating an actual subcooling degree SC, SC=CT-TLq.
- Step S4: calculating a difference between a target subcooling degree ST and the actual subcooling degree SC, ΔT = ST-SC.
- The target subcooling degree ST is a preset target value. When the refrigerant in the main liquid pipe reaches the target subcooling degree ST, noise will not occur as flowing into the indoor units.
- Step S5: Adjusting the throttling structure according to the difference ΔT, and returning to step S1.
- The throttling structure is being adjusted according to the difference ΔT until ΔT=0.
- The control method of the cooling-heating switching device for heat-recovery multi-split air conditioning system of this embodiment provides an effective solution to the loud flowing sound problem of the heat-recovery multi-split air conditioning system in the prior art by means of procedures including: obtaining a saturation temperature CT corresponding to an outdoor unit high pressure; obtaining a temperature TLq at a main pipe outlet of a subcooler; calculating an actual subcooling degree SC, SC=CT-TLq; calculating a difference between a target subcooling degree ST and the actual subcooling degree SC, ΔT = ST-SC; adjusting the throttling structure according to the difference ΔT until ΔT=0; with which liquid refrigerant in the main
liquid pipe 1 could reach a better subcooling degree so that noise will not occur as flowing into the indoor units, and liquid refrigerant in the mainliquid pipe 1 will not vaporize to flash gas due to insufficient subcooling so the problem of unbalanced refrigerant distribution between indoor units working in cooling mode could be prevented. - In the present embodiment, the adjusting the throttling structure according to the difference ΔT specifically includes:
If the difference ΔT> 0, adjusting the throttling structure to reduce the amount of refrigerant flowing in a connection pipe between the cooling branch inlet of the subcooler and the main pipe outlet of the subcooler, so as to increase the temperature TLq at the main pipe outlet preventing the subcooling degree too low to affect the refrigerant flow in the main liquid pipe. - If the difference ΔT <0, adjusting the throttling structure to increase the amount of refrigerant flowing in a connection pipe between the cooling branch inlet of the subcooler and the main pipe outlet of the subcooler, so as to reduce the temperature TLq at the main pipe outlet to lower the subcooling degree.
- The above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, for those of ordinary skill in the art, the technical solutions of the foregoing embodiments can still be described. The recorded technical solutions are modified, or some of the technical features are equivalently replaced; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions claimed by the present invention.
Claims (10)
- A cooling-heating switching device for heat-recovery multi-split air conditioning system, characterized in that includes: a main liquid pipe, a high-pressure gas pipe, a plurality of high-pressure branch pipes, a low-pressure gas pipe, a plurality of low-pressure branch pipes, a subcooler, a plurality of branch liquid pipes and a plurality of liquid distribution pipes;
wherein the high-pressure gas pipe is connected to a high-pressure gas pipe of an outdoor unit and the low-pressure gas pipe is connected to a low-pressure gas pipe of the outdoor unit, and the main liquid pipe is connected to the liquid pipe of the outdoor unit;
one end of each high-pressure branch pipe is connected to one end of each low-pressure branch pipe in a one-to-one correspondence forming a plurality of connection nodes; the connection nodes are connected to gas pipes of indoor units in a one-to-one correspondence;
the other end of each high-pressure branch pipe is connected to the high-pressure gas pipe, and each high-pressure branch pipe is provided with a valve;
the other end of each low-pressure branch pipe is connected to the low-pressure gas pipe, and each low-pressure branch pipe is provided with a valve;
one end of each branch liquid pipe is connected to one end of each liquid distribution pipe in a one-to-one correspondence so as to form a plurality of connection points, and the plurality of connection points are connected to the liquid pipe of each indoor unit in a one-to-one correspondence;
the other end of each branch liquid pipe is respectively connected to the main liquid pipe 1, and each branch liquid pipe is provided with a valve that opens and closes to control the flow in the branch liquid pipe;
the other end of each liquid distribution pipe is respectively connected to a main pipe inlet of the subcooler, and each liquid distribution pipe is provided with a valve; and
a main pipe outlet of the subcooler is connected to the main liquid pipe; a cooling branch pipe inlet of the subcooler is connected to the main pipe outlet of the subcooler, a throttle structure VSC is disposed in the connection pipe between the cooling branch pipe inlet and the main pipe outlet of the subcooler; a cooling branch pipe outlet of the subcooler is connected to the low-pressure gas pipe. - A cooling-heating switching device for heat-recovery multi-split air conditioning system according to claim 1, characterized in that the valves on the high-pressure branch pipes are driven by a main control board of the cooling-heating switching device.
- A cooling-heating switching device for heat-recovery multi-split air conditioning system according to claim 1, characterized in that the valves on the low-pressure branch pipes are driven by a main control board of the cooling-heating switching device.
- A cooling-heating switching device for heat-recovery multi-split air conditioning system according to claim 1, characterized in that the valves provided on the branch liquid pipes are one-way valves, wherein an inlet of each one-way valve is respectively connected to the main liquid pipe and an outlet of each one-way valve is connected to a liquid pipe of an indoor unit;
or, the valves provided on the branch liquid pipes are solenoid valves or electronic expansion valves which are driven by a main control board of the cooling-heating switching device. - A cooling-heating switching device for heat-recovery multi-split air conditioning system according to claim 1, characterized in that the valves provided on the liquid distribution pipes are one-way valves, wherein an inlet of each one-way valve is respectively connected to a liquid pipe of an indoor unit and an outlet of each one-way valve is respectively connected to the main pipe inlet of the subcooler;
or, the valves provided on the liquid distribution pipes are solenoid valves or electronic expansion valves, which are driven by a main control board of the cooling-heating switching device. - A cooling-heating switching device for heat-recovery multi-split air conditioning system according to claim 1, characterized in that the throttling structure is an electronic expansion valve, a thermal expansion valve, a solenoid valve and capillary tube connected in series which is driven by a main control board of the cooling-heating switching device.
- A cooling-heating switching device for heat-recovery multi-split air conditioning system according to claim 1, characterized in that a temperature sensor is provided at a main pipe outlet of the subcooler.
- A heat-recovery multi-split air conditioning system includes an outdoor unit and a plurality of indoor units, characterized in that, further includes a cooling-heating switching device according to any one of claim 1 to claim 7.
- A control method based on the cooling-heating switching device according to any one of claim 1 to claim 7, characterized in that, includes:(1) obtaining a saturation temperature CT corresponding to an outdoor unit high pressure;(2) obtaining a temperature TLq at a main pipe outlet of a subcooler;(3) calculating an actual subcooling degree SC, SC=CT-TLq;(4) calculating a difference between a target subcooling degree ST and the actual subcooling degree SC, ΔT = ST-SC;(5) adjusting the throttling structure according to the difference ΔT, and returning to step (1).
- A control method according to claim 9, characterized in that: the adjustment of the throttling structure according to the difference ΔT includes:if the difference ΔT > 0, adjusting the throttling structure to reduce the amount of refrigerant flowing in a connection pipe between the cooling branch inlet of the subcooler and the main pipe outlet of the subcooler;if the difference ΔT <0, adjusting the throttling structure to increase the amount of refrigerant flowing in a connection pipe between the cooling branch inlet of the subcooler and the main pipe outlet of the subcooler.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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CN201811110339.1A CN109357429A (en) | 2018-09-21 | 2018-09-21 | A kind of heat-reclamation multi-compressors cool-warm switching device, multi-connected machine and control method |
PCT/CN2019/092372 WO2020057210A1 (en) | 2018-09-21 | 2019-06-21 | Cooling and heating switching device for variable refrigerant flow system capable of heat recovery, variable refrigerant flow system, and control method |
Publications (2)
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EP3855094A1 true EP3855094A1 (en) | 2021-07-28 |
EP3855094A4 EP3855094A4 (en) | 2021-12-08 |
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EP19861762.3A Withdrawn EP3855094A4 (en) | 2018-09-21 | 2019-06-21 | Cooling and heating switching device for variable refrigerant flow system capable of heat recovery, variable refrigerant flow system, and control method |
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EP (1) | EP3855094A4 (en) |
CN (1) | CN109357429A (en) |
WO (1) | WO2020057210A1 (en) |
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CN109357429A (en) * | 2018-09-21 | 2019-02-19 | 青岛海尔空调电子有限公司 | A kind of heat-reclamation multi-compressors cool-warm switching device, multi-connected machine and control method |
CN110360780B (en) * | 2019-07-23 | 2020-11-24 | 珠海格力电器股份有限公司 | Multi-split air conditioning system, supercooling degree determination method, device and equipment thereof and storage medium |
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KR100539570B1 (en) * | 2004-01-27 | 2005-12-29 | 엘지전자 주식회사 | multi airconditioner |
JP2009228979A (en) * | 2008-03-24 | 2009-10-08 | Mitsubishi Electric Corp | Air conditioner |
CN102042648B (en) * | 2010-11-29 | 2012-10-03 | 青岛海信日立空调***有限公司 | Heat recovery type multi-connection air condition unit |
KR102008710B1 (en) * | 2013-01-22 | 2019-08-09 | 엘지전자 주식회사 | An air conditioner and a control method the same |
WO2014128830A1 (en) * | 2013-02-19 | 2014-08-28 | 三菱電機株式会社 | Air conditioning device |
JP5812084B2 (en) * | 2013-12-11 | 2015-11-11 | ダイキン工業株式会社 | Channel switching collective unit and method for manufacturing channel switching collective unit |
CN204329177U (en) * | 2014-12-19 | 2015-05-13 | 特灵空调***(中国)有限公司 | Carry the indoor set of supercooling apparatus |
CN107401849B (en) * | 2017-08-15 | 2019-12-27 | 广东美的暖通设备有限公司 | Multi-split air conditioning system and control method and device of supercooling loop valve body thereof |
CN207146975U (en) * | 2017-09-12 | 2018-03-27 | 珠海格力电器股份有限公司 | Heat recovery multi-split air conditioning system |
CN107843037B (en) * | 2017-10-31 | 2021-02-23 | 广东美的暖通设备有限公司 | Multi-split air conditioning system and supercooling control device and method thereof |
CN108036551A (en) * | 2017-12-18 | 2018-05-15 | 广东美的暖通设备有限公司 | Switching device and there is its multi-gang air-conditioner |
CN109357429A (en) * | 2018-09-21 | 2019-02-19 | 青岛海尔空调电子有限公司 | A kind of heat-reclamation multi-compressors cool-warm switching device, multi-connected machine and control method |
-
2018
- 2018-09-21 CN CN201811110339.1A patent/CN109357429A/en active Pending
-
2019
- 2019-06-21 EP EP19861762.3A patent/EP3855094A4/en not_active Withdrawn
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