WO2024098966A1 - Système de pompe à chaleur et procédé de commande pour système de pompe à chaleur - Google Patents

Système de pompe à chaleur et procédé de commande pour système de pompe à chaleur Download PDF

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Publication number
WO2024098966A1
WO2024098966A1 PCT/CN2023/119728 CN2023119728W WO2024098966A1 WO 2024098966 A1 WO2024098966 A1 WO 2024098966A1 CN 2023119728 W CN2023119728 W CN 2023119728W WO 2024098966 A1 WO2024098966 A1 WO 2024098966A1
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WIPO (PCT)
Prior art keywords
pressure
compressor
heat pump
pump system
stage compressor
Prior art date
Application number
PCT/CN2023/119728
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English (en)
Chinese (zh)
Inventor
叶文腾
钟瑞兴
陈玉辉
董迎波
Original Assignee
珠海格力电器股份有限公司
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Publication of WO2024098966A1 publication Critical patent/WO2024098966A1/fr

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Classifications

    • 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
    • F25B1/00—Compression machines, plants or systems with non-reversible cycle
    • F25B1/10—Compression machines, plants or systems with non-reversible cycle with multi-stage compression
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H4/00—Fluid heaters characterised by the use of heat pumps
    • F24H4/02—Water heaters
    • 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
    • F25B41/24—Arrangement of shut-off valves for disconnecting a part of the refrigerant cycle, e.g. an outdoor part
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/40—Fluid line arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • 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

Definitions

  • the present disclosure relates to the technical field of heat pumps, and in particular to a heat pump system and a control method of the heat pump system.
  • Heat pump technology utilizes electricity and suitable low-grade heat sources, and uses a heat pump system to provide thermal energy to meet heat needs such as building heating and domestic hot water. It is the best way to efficiently convert electricity into heat.
  • the heat pump system has the advantages of environmental protection, energy saving and high efficiency. In recent years, it has been more and more widely used in large-scale central heating systems. In winter, when the heat source temperature is as low as -15°C, the heat pump system produces 50°C hot water, and the required compressor operating pressure ratio is as high as 9.0.
  • the existing heat pump system mainly uses a two-stage centrifugal compressor as a compression device.
  • the maximum pressure ratio of the two-stage centrifugal compressor is about 4.5, and the operating pressure ratio required by the heat pump system when operating in heating mode is far beyond the pressure ratio limit of the two-stage centrifugal compressor.
  • the compression device operating pressure ratio is 3.0. As a result, it is difficult for the two-stage centrifugal compressor to match the high pressure ratio of the heat pump system when it is operating in heating mode and the low pressure ratio when it is operating in cooling mode.
  • the present disclosure aims to provide a heat pump system and a control method for the heat pump system, aiming to solve the problem in the related art that a two-stage centrifugal compressor is difficult to match a high pressure ratio when operating in a heating mode and a low pressure ratio when operating in a cooling mode.
  • a first aspect of the present disclosure provides a heat pump system, comprising a refrigerant circulation circuit, the refrigerant circulation circuit comprising a main refrigerant pipeline and an evaporator, a compression device, a condenser and a throttling device connected in sequence through the main refrigerant pipeline, the heat pump system having a cooling mode and a heating mode;
  • the compression device comprises a low-pressure compressor and a high-pressure compressor connected in series through a main refrigerant pipeline, the inlet of the low-pressure compressor is connected to the evaporator through the main refrigerant pipeline, and the outlet of the low-pressure compressor is connected to the evaporator through the main refrigerant pipeline.
  • the refrigerant pipeline is connected to the inlet of the high-pressure compressor, and the outlet of the high-pressure compressor is connected to the condenser through the main refrigerant pipeline;
  • the refrigerant circulation loop further includes a switching device, which is connected to the main refrigerant pipeline and is configured to enable the refrigerant circulation loop to have a single compressor working state in the cooling mode and a dual compressor working state in the heating mode.
  • a switching device which is connected to the main refrigerant pipeline and is configured to enable the refrigerant circulation loop to have a single compressor working state in the cooling mode and a dual compressor working state in the heating mode.
  • the high-pressure stage compressor compresses the refrigerant in the refrigerant circulation loop
  • the low-pressure stage compressor stops compressing the refrigerant.
  • the dual compressor working state the low-pressure stage compressor and the high-pressure stage compressor are connected in series and compress the refrigerant.
  • the pressure ratio of the high-pressure stage compressor is configured to satisfy the pressure ratio required by the compression device of the heat pump system in the cooling mode when the single compressor is in operation;
  • the pressure ratio of the low-pressure stage compressor is configured to satisfy the pressure ratio required by the compression device of the heat pump system in the heating mode together with the high-pressure stage compressor when the two compressors are in operation.
  • the pressure ratio of the high-pressure stage compressor is configured to be 1.02 to 1.06 times the pressure ratio required by the compression device of the heat pump system in the cooling mode; and/or
  • the pressure ratio of the low-pressure stage compressor is configured to be 1.04 to 1.06 times the pressure ratio that the low-pressure stage compressor needs to bear when the two compressors are in working state and together with the high-pressure stage compressor meet the pressure ratio required by the compression device of the heat pump system in the heating mode.
  • the switching device includes:
  • bypass portion comprising a bypass pipeline connected to the main refrigerant pipeline in parallel with the low-pressure stage compressor;
  • the switching unit is configured to selectively connect one of the bypass line and the low-pressure stage compressor to the refrigerant circulation circuit and disconnect the other from the refrigerant circulation circuit.
  • the switching unit includes a first switching valve, which is disposed on the bypass pipeline and is configured to control the on-off of the bypass pipeline.
  • the refrigerant circulation loop further includes:
  • a flasher connected to the main refrigerant pipeline between the condenser and the evaporator;
  • the gas supply pipeline connects the gas outlet of the flasher and the compression device, and is configured to supply gas to the compression device.
  • the air supply pipeline includes:
  • a first air supply branch connected between the gas outlet of the flash generator and the inlet of the high-pressure compressor;
  • the second air supply branch is connected between the gas outlet of the flash generator and the air supply port of the high-pressure compressor.
  • the refrigerant circulation loop further includes:
  • a series air supply control valve disposed on the first air supply branch, configured to control the on-off of the first air supply branch
  • the high-pressure air supply control valve is arranged on the second air supply branch and is configured to control the on-off of the second air supply branch.
  • the throttling device includes a first throttling part and a second throttling part connected through the main refrigerant pipeline, and the flasher is located on the main refrigerant pipeline between the first throttling part and the second throttling part.
  • the flash generator is installed on the condenser.
  • the low-pressure stage compressor is a two-stage centrifugal compressor
  • the high-pressure stage compressor is a two-stage centrifugal compressor.
  • the low-pressure compressor is mounted on the evaporator; and/or
  • the high-pressure stage compressor is mounted on the condenser.
  • the low-pressure stage compressor is a fixed-speed compressor
  • the high-pressure stage compressor is a fixed-speed compressor.
  • the low pressure stage compressor includes adjustable inlet guide vanes; and/or
  • the high pressure stage compressor includes adjustable inlet guide vanes.
  • F1 is the volume flow of the low-pressure stage compressor
  • F2 is the volume flow of the high pressure compressor
  • A is a constant representing the ratio of the outlet specific volume of the high-pressure stage compressor in the cooling mode to the outlet specific volume in the heating mode.
  • the heat pump system further includes a water circulation loop, wherein the water circulation loop includes a main water path, A heat source tower and a terminal heat exchanger, wherein the heat source tower is switchably connected to one of the evaporator and the condenser through the main water circuit, and the terminal heat exchanger is switchably connected to the other of the evaporator and the condenser through the main water circuit.
  • a second aspect of the present disclosure provides a control method for the heat pump system according to the first aspect of the present disclosure, comprising:
  • the refrigerant circulation loop In the cooling mode of the heat pump system, the refrigerant circulation loop is placed in the single compressor working state;
  • the refrigerant circulation loop is put into the working state of the two compressors.
  • the refrigerant circulation loop further includes a flasher and an air supply pipeline, wherein the flasher is connected to the main refrigerant pipeline between the condenser and the evaporator, and the air supply pipeline connects the gas outlet of the flasher and the compression device and is configured to supply air to the compression device;
  • the control method includes supplying air from the flasher to the compression device through the air supply pipeline.
  • supplying air from the flasher to the compression device comprises:
  • air is supplied to the air inlet and/or air supply port of the high-pressure stage compressor.
  • the high-pressure stage compressor includes an adjustable inlet guide vane
  • the control method also includes adjusting the opening of the adjustable inlet guide vane of the high-pressure stage compressor to change the supplementary air pressure when supplementing air to the compression device.
  • the low-pressure stage compressor includes an adjustable inlet guide vane; and/or the high-pressure stage compressor includes an adjustable inlet guide vane;
  • the control method includes: in the heating mode, adjusting the opening of the adjustable inlet guide vane of the low-pressure stage compressor and/or adjusting the opening of the adjustable inlet guide vane of the high-pressure stage compressor so that the low-pressure stage compressor and the high-pressure stage compressor jointly meet the required pressure ratio of the compression device of the heat pump system in the heating mode.
  • control method includes: in the heating mode, fully opening the adjustable inlet guide vanes of the low-pressure stage compressor, and adjusting the opening degree of the adjustable inlet guide vanes of the high-pressure stage compressor so that the low-pressure stage compressor and the high-pressure stage compressor can jointly meet the required pressure ratio of the compression device of the heat pump system in the heating mode.
  • the refrigerant circulation loop when operating in winter heating mode, can be cut off.
  • the dual compressor working state use the low-pressure compressor and the high-pressure compressor in series to compress the refrigerant to meet the high pressure ratio requirements for winter heating.
  • the high-pressure compressor designed according to the pressure ratio required by the cooling mode use the high-pressure compressor designed according to the pressure ratio required by the cooling mode to independently compress the refrigerant to match the operating pressure ratio required for refrigeration, which is conducive to ensuring the high efficiency of the high-pressure compressor in single operation in cooling mode.
  • the required operating pressure ratio matching in different operating modes is achieved, which is conducive to ensuring the stability of high-pressure ratio operation in winter heating, and improving the energy efficiency of low-pressure ratio operation in summer cooling.
  • control method of the heat pump system according to the embodiment of the present disclosure has the advantages of the heat pump system according to the embodiment of the present disclosure.
  • FIG1 is a schematic diagram of a heat pump system according to an embodiment of the present disclosure, which shows a refrigerant circulation loop and a water circulation loop of the heat pump system.
  • FIG. 2 is a schematic diagram of a refrigerant circulation circuit of the heat pump system of the embodiment shown in FIG. 1 .
  • FIG. 3 is a schematic diagram of the operating characteristics of the compression device of the heat pump system of the embodiment shown in FIG. 1 .
  • the orientation or positional relationship indicated by the directional words is usually based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present disclosure and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present disclosure; the directional words "inside and outside” refer to the inside and outside relative to the outline of each component itself.
  • Fig. 1 is a schematic diagram of a heat pump system according to an embodiment of the present disclosure, which shows a refrigerant circulation loop and a water circulation loop of the heat pump system.
  • Fig. 2 is a schematic diagram of a refrigerant circulation loop of the heat pump system according to the embodiment shown in Fig. 1 .
  • an embodiment of the present disclosure provides a heat pump system, including a refrigerant circulation loop, the refrigerant circulation loop including a main refrigerant pipeline 13 and an evaporator 3, a compression device, a condenser 4 and a throttling device connected in sequence through the main refrigerant pipeline 13.
  • the heat pump system has a cooling mode and a heating mode.
  • the compression device includes a low-pressure compressor 1 and a high-pressure compressor 2 connected in series through the main refrigerant pipeline 13, the inlet of the low-pressure compressor 1 is connected to the evaporator 3 through the main refrigerant pipeline 13, the outlet of the low-pressure compressor 1 is connected to the inlet of the high-pressure compressor 2 through the main refrigerant pipeline 13, and the outlet of the high-pressure compressor 2 is connected to the condenser 4 through the main refrigerant pipeline 13.
  • the refrigerant circulation loop also includes a switching device, which is connected to the main refrigerant pipeline 13 and is configured to enable the refrigerant circulation loop to have a single compressor working state in the cooling mode and a double compressor working state in the heating mode.
  • the high-pressure stage compressor 2 independently compresses the refrigerant in the refrigerant circulation loop, and the low-pressure stage compressor 1 stops compressing the refrigerant.
  • the low-pressure stage compressor 1 and the high-pressure stage compressor 2 are connected in series and compress the refrigerant.
  • the pressure ratio of the high-pressure stage compressor 2 is configured to meet the pressure ratio required by the compression device of the heat pump system in the cooling mode when operating in a single compressor working state.
  • the pressure ratio of the low-pressure stage compressor 1 is configured to meet the pressure ratio required by the compression device of the heat pump system in the heating mode together with the high-pressure stage compressor 2 when operating in the dual compressor working state.
  • the refrigerant circulation loop can be switched to the double compressor working state, using the low-pressure compressor 1 and the high-pressure compressor 2.
  • the compressors are connected in series to compress the refrigerant to meet the high pressure ratio requirements for winter heating. For example, hot water at 50°C can be produced normally when the heat source temperature is -15°C.
  • the cooling needs in summer when the heat pump system is running in cooling mode, only the high-pressure compressor 2 is turned on.
  • the high-pressure compressor 2 designed according to the pressure ratio required by the cooling mode is used to independently compress the refrigerant to match the operating pressure ratio required for refrigeration, which is conducive to ensuring the high efficiency of the high-pressure compressor in single operation in cooling mode.
  • the required operating pressure ratio matching in different operating modes is achieved, which is conducive to ensuring the stability of high-pressure ratio operation in winter heating and improving the energy efficiency of low-pressure ratio operation in summer cooling.
  • the pressure ratio of the high-pressure stage compressor 2 is configured to be 1.02 to 1.05 times the pressure ratio required by the compression device of the heat pump system in the cooling mode; and/or the pressure ratio of the low-pressure stage compressor 1 is configured to be 1.04 to 1.06 times the pressure ratio that the low-pressure stage compressor 1 needs to bear when the two compressors are in the working state and together with the high-pressure stage compressor 2 meet the pressure ratio required by the compression device of the heat pump system in the heating mode.
  • the above arrangement allows unpredictable factors in the actual operation of the heat pump system to be taken into consideration when designing the corresponding pressure ratios of the low-pressure stage compressor 1 and the high-pressure stage compressor 2, and a certain margin is reserved when designing the pressure ratio.
  • FIG3 is a schematic diagram of the operating characteristics of the low-pressure compressor and the high-pressure compressor of the heat pump system of the embodiment shown in FIG1.
  • the horizontal axis F represents the volume flow rate
  • the vertical axis R represents the pressure ratio
  • each curve represents:
  • L1 is the surge line
  • L2 is the pipe network characteristic curve under the working state of two compressors
  • L3 is the pipe network characteristic curve under the working state of a single compressor
  • C1 is the characteristic curve of the compression device under the working state of two compressors
  • C2 is the characteristic curve of low-pressure compressor 1 when the opening of its adjustable inlet guide vane is 100% under the dual compressor working state;
  • C3 is the characteristic curve of the high-pressure stage compressor 2 when the opening of its adjustable inlet guide vane is 100% under the single compressor working state;
  • C4 is the characteristic curve of the high-pressure stage compressor 2 when the opening of its adjustable inlet guide vane is less than 100% under the single compressor working state;
  • F1 is the volume flow of the low-pressure stage compressor 1, hereinafter referred to as the first volume flow;
  • F2 is the volume flow of the high pressure stage compressor 2, hereinafter referred to as the second volume flow;
  • R1 is the pressure ratio of the compression device when the exhaust volume of the compression device is the first volume flow F1 under the working state of two compressors, hereinafter referred to as the first pressure ratio;
  • R2 is the low-pressure compression when the exhaust volume of the compression device is the first volume flow F1 under the working state of the two compressors.
  • the pressure ratio of the machine 1 when the opening of its adjustable inlet guide vane is 100%, hereinafter referred to as the second pressure ratio;
  • R3 is the pressure ratio of the high-pressure stage compressor 2 when the exhaust volume of the compression device is the first volume flow F1 under the working state of the two compressors and the opening of the adjustable inlet guide vane is less than 100%, hereinafter referred to as the third pressure ratio;
  • R4 is the pressure ratio of the high-pressure stage compressor 2 when the adjustable inlet guide vane opening is 100% when the exhaust volume of the compression device is the second volume flow F2 in the single compressor working state, hereinafter referred to as the fourth pressure ratio.
  • the first pressure ratio R1, the second pressure ratio R2 and the third pressure ratio all correspond to the first volume flow F1.
  • the first pressure ratio R1 refers to the total pressure ratio of the compression device for the heating demand of the heat pump system, that is, the pressure ratio of the compression device when the low-compression compressor 1 and the high-pressure compressor 2 work in series to compress the refrigerant under the working state of two compressors, and the two compressors operate at the second pressure ratio R2 and the third pressure ratio R3 respectively.
  • the first pressure ratio R1 the second pressure ratio R2 * the third pressure ratio R3.
  • the fourth pressure ratio R4 corresponds to the second volume flow F2.
  • the high pressure stage compressor 2 works alone to compress the refrigerant to meet the refrigeration demand of the heat pump system.
  • the pressure ratio required by the compression device of the aforementioned heat pump system in the cooling mode is the fourth pressure ratio R4.
  • the pressure ratio of the high-pressure stage compressor 2 is configured to be 1.02 to 1.05 times the pressure ratio required by the compression device of the heat pump system in the cooling mode, that is, the pressure ratio of the high-pressure stage compressor 2 is configured to be 1.02 to 1.05 times, for example, 1.03 times, of the fourth pressure ratio R4.
  • the pressure ratio that the low-pressure compressor 1 needs to bear when the two compressors work together with the high-pressure compressor 2 to meet the required pressure ratio of the compression device of the heat pump system in the heating mode is the second pressure ratio R2.
  • the pressure ratio of the low-pressure compressor 1 is configured to be 1.01 to 1.08 times the pressure ratio that the low-pressure compressor 1 needs to bear when the two compressors work together with the high-pressure compressor 2 to meet the required pressure ratio of the heat pump system in the heating mode, that is, the pressure ratio of the low-pressure compressor 1 is configured to be 1.01 to 1.08 times, for example, 1.06 times, of the second pressure ratio R2.
  • the switching device includes a bypass part and a switching part.
  • the bypass part includes a bypass line 14 connected in parallel with the low-pressure stage compressor 1.
  • the switching part is configured to selectively connect one of the bypass line 14 and the low-pressure stage compressor 1 to the refrigerant circulation circuit, and disconnect the other from the refrigerant circulation circuit.
  • the switching unit includes a first switching valve 6, which is disposed on the bypass line 14 and is configured to control the on-off of the bypass line 14.
  • the first switching valve 6 When the first switching valve 6 is opened, the refrigerant passes through the bypass line 14, the low-pressure stage compressor 1 does not participate in the compression of the refrigerant, and the high-pressure stage compressor 2 alone compresses the refrigerant.
  • the first switching valve 6 When the first switching valve 6 is disconnected, the low-pressure stage compressor 1 and the high-pressure stage compressor 2 work in series to compress the refrigerant.
  • the first switching valve 6 is, for example, an electric valve, such as an electric butterfly valve.
  • a second switching valve can also be provided.
  • the second switching valve can be provided on the main refrigerant pipeline 13 between the inlet of the low-pressure stage compressor 1 and the bypass pipeline 14 or on the main refrigerant pipeline 13 between the outlet of the low-pressure stage compressor 1 and the bypass pipeline 14.
  • the refrigerant circulation loop further includes a flasher 5 and an air supply pipeline.
  • the flasher 5 is connected to the main refrigerant pipeline 13 between the condenser 4 and the evaporator 3.
  • the air supply pipeline connects the gas outlet of the flasher 5 and the compression device, and is configured to supply air to the compression device.
  • the air supply pipeline includes at least one of a first air supply branch 15 and a second air supply branch 16.
  • the first air supply branch 15 is connected between the gas outlet of the flasher 5 and the inlet of the high-pressure compressor 2.
  • the second air supply branch 16 is connected between the gas outlet of the flasher 5 and the air supply port of the high-pressure compressor 2.
  • the refrigerant circulation loop includes at least one of a series air supply control valve 8 and a high-pressure air supply control valve 9.
  • the series air supply control valve 8 is arranged on the first air supply branch 15 and is configured to control the on-off of the first air supply branch 15.
  • the high-pressure air supply control valve 9 is arranged on the second air supply branch 16 and is configured to control the on-off of the second air supply branch 16.
  • the series air supply control valve 8 and the high-pressure air supply control valve 9 are, for example, electric valves, which may be electric butterfly valves, electric ball valves, or solenoid valves.
  • the throttling device includes a first throttling portion 11 and a second throttling portion 12 connected by a main refrigerant pipeline 13 , and the flasher 5 is located on the main refrigerant pipeline 13 between the first throttling portion 11 and the second throttling portion 12 .
  • the flash generator 5 is installed on the condenser 4 .
  • the refrigerant circulation loop may further include a check valve, which is disposed on the main refrigerant pipeline 13 between the outlet of the high-pressure compressor 2 and the condenser 4.
  • the check valve helps prevent the high-pressure gas in the condenser 4 from flowing back when the compression device is shut down, causing the compression device to reverse.
  • the low-pressure stage compressor 1 and the high-pressure stage compressor 2 may both be centrifugal compressors, for example, the low-pressure stage compressor 1 is a two-stage centrifugal compressor; the high-pressure stage compressor 2 is a two-stage centrifugal compressor.
  • the low-pressure stage compressor 1 is a fixed-speed compressor; and/or the high-pressure stage compressor 2 is a fixed-speed compressor.
  • the low-pressure stage compressor and the high-pressure stage compressor can both be fixed-frequency centrifugal compressors.
  • the low-pressure compressor 1 includes an adjustable inlet guide vane; and/or the high-pressure compressor 2 includes an adjustable inlet guide vane. This arrangement is conducive to adjusting the refrigerant flow and pressure of the heat pump system according to different working conditions of the heat pump system.
  • F1 is the volume flow of the low-pressure compressor
  • F2 is the volume flow of the high-pressure compressor
  • A is a constant representing the ratio of the outlet specific volume of the high-pressure compressor 2 in the cooling mode to the outlet specific volume in the heating mode.
  • the gas specific volume decreases, and the required flow channel is narrow when it reaches the high-pressure compressor 2.
  • V2 Vin /(P2/P1)1/k.
  • Vin is the inlet specific volume of the high-pressure compressor 2
  • P2 is the outlet pressure of the high-pressure compressor 2
  • P1 is the inlet pressure of the high-pressure compressor 2
  • k is the adiabatic index.
  • the above parameters are different in cooling mode and heating mode, so the outlet specific volume of the high-pressure compressor 2 is different in cooling mode and heating mode. Therefore, a constant A can be used to represent the ratio of the outlet specific volume of the high-pressure compressor 2 in cooling mode to the outlet specific volume in heating mode.
  • the low-pressure stage compressor 1 is installed on the evaporator 3
  • the high-pressure stage compressor 2 is installed on the condenser 4 .
  • the heat pump system also includes a water circulation loop, the water circulation loop includes a main water line 77, a heat source tower 71 and a terminal heat exchanger 73, the heat source tower 71 is switchably connected to one of the evaporator 3 and the condenser 4 through the main water line 77, and the terminal heat exchanger 73 is switchably connected to the other of the evaporator 3 and the condenser 4 through the main water line 77.
  • the heat pump system of the embodiment of the present disclosure includes a refrigerant circulation circuit and a water circulation circuit as shown in FIG2 .
  • the refrigerant circulation circuit refers to the previous description, and the water circulation circuit mainly includes a main water circuit 77, a heat source tower 71, a first circulation water pump 72, a terminal heat exchanger 73, a second circulation water pump 74, a working mode switching unit 70, a concentrating device 75, a third circulation water pump 76, and a concentrating branch 78.
  • the heat source tower 71 and the first circulation water pump 72 are connected in series through the main water circuit 77, and are switchably connected to one of the evaporator 3 and the condenser 4 through the working mode switching unit 70.
  • the terminal heat exchanger 73 and the second circulation water pump 74 are connected in series through the main water circuit 77, and are switchably connected to the other of the evaporator 3 and the condenser 4 through the main water circuit 77 and the working mode switching unit 70.
  • the heat source tower 71, the first circulating water pump 72, the working mode switching unit 70 and the evaporator 3 are sequentially connected through the main water path 77 to form a circulation loop; at the same time,
  • the terminal heat exchanger 73, the second circulating water pump 74, the working mode switching unit 70 and the condenser 4 are connected in sequence through the main water path 77 to form a circulation loop.
  • the heat pump system is in the heating mode.
  • the working mode switching unit 70 can be switched to connect the heat source tower 71, the first circulating water pump 72, the working mode switching unit 70 and the condenser 4 in sequence through the main water channel 77 to form a circulation loop; at the same time, the terminal heat exchanger 73, the second circulating water pump 74, the working mode switching unit 70 and the evaporator 3 are connected in sequence through the main water channel 77 to form a circulation loop.
  • the first circulating water pump 72 is used to provide power for the circulating loop where the heat source tower 71 is located, and the second circulating water pump 72 is used to provide power for the circulating loop where the terminal heat exchanger 73 is located.
  • the concentrating device 75 , the third circulating water pump 76 , and the concentrating branch 78 are configured to concentrate and store the antifreeze liquid.
  • the first switching valve 6 is closed, the series air supply control valve 8 is opened, and the high-pressure air supply control valve 9 is closed.
  • the gaseous refrigerant in the evaporator 3 is compressed by the low-pressure compressor 1 and discharged, enters the high-pressure compressor 2 for further compression, and is discharged into the condenser 4.
  • the liquid refrigerant in the condenser 4 enters the flasher 5 after the first throttling of the first throttling part 11.
  • the gaseous refrigerant after flashing is mixed with the exhaust gas of the low-pressure compressor 1 through the series air supply control valve 8, and then enters the high-pressure compressor 2.
  • the liquid refrigerant after flashing enters the evaporator 3 after the second throttling of the second throttling part 12, thereby realizing the cycle.
  • the first switching valve 6 is opened, the series air supply control valve 8 is closed, and the high-pressure air supply control valve 9 is opened.
  • the gaseous refrigerant of the evaporator 3 directly enters the high-pressure compressor 2 through the first switching valve 6 for compression, and then is discharged into the condenser 4.
  • the liquid refrigerant of the condenser 4 enters the flasher 5 after primary throttling through the first throttling part 11.
  • the gaseous refrigerant after flashing enters the air supply port of the high-pressure compressor 2 through the high-pressure air supply control valve 9.
  • the liquid refrigerant after flashing enters the evaporator 3 after secondary throttling through the second throttling part 12, thereby realizing circulation.
  • the present disclosure also provides a control method for the heat pump system of the present disclosure.
  • the control method includes: in the cooling mode of the heat pump system, the refrigerant circulation loop is in a single compressor working state; in the heating mode of the heat pump system, the refrigerant circulation loop is in a dual compressor working state.
  • control method of the embodiment of the present disclosure has the same advantages as the heat pump system of the embodiment of the present disclosure.
  • the refrigerant circulation loop also includes a flasher 5 and an air supply pipeline.
  • the flasher 5 is connected to the main refrigerant pipeline 13 between the condenser 4 and the evaporator 3.
  • the air supply pipeline connects the gas outlet of the flasher 5 and the compression device, and is configured to supply air to the compression device.
  • the control method includes supplying air from the flasher 5 to the compression device.
  • air in the cooling mode of the heat pump system, air is supplied to the air supply port of the high-pressure stage compressor 2; and/or in the heating mode of the heat pump system, air is supplied to the air supply port and/or the air inlet of the high-pressure stage compressor 2.
  • control method further comprises adjusting the opening of the adjustable inlet guide vane of the high-pressure stage compressor 2 to change the supplementary air pressure when supplementing air to the compression device.
  • control method includes: in the heating mode, adjusting the opening of the adjustable inlet guide vane of the low-pressure stage compressor 1 and/or adjusting the opening of the adjustable inlet guide vane of the high-pressure stage compressor 2 so that the low-pressure stage compressor 1 and the high-pressure stage compressor 2 can jointly meet the pressure ratio required by the compression device of the heat pump system in the heating mode.
  • control method includes: in the heating mode, fully opening the adjustable inlet guide vanes of the low-pressure stage compressor 1, and adjusting the opening degree of the adjustable inlet guide vanes of the high-pressure stage compressor 2 so that the low-pressure stage compressor 1 and the high-pressure stage compressor 2 can jointly meet the pressure ratio required by the compression device of the heat pump system in the heating mode.
  • the heat pump system and the control method of the heat pump system according to the embodiment of the present disclosure have at least one of the following advantages:
  • a low-pressure compressor and a high-pressure compressor are connected in series to compress the refrigerant, which is conducive to achieving the high pressure ratio required for winter heating.
  • a high-pressure compressor is used to compress the refrigerant alone to match the operating pressure ratio required for cooling. This is conducive to ensuring stability when operating at a high pressure ratio for winter heating, and improving energy efficiency when operating at a low pressure ratio for summer cooling.
  • both compressors are two-stage compressors
  • the two compressors in series compressing the refrigerant is equivalent to a four-stage compressor compressing the refrigerant, which is more conducive to meeting the high pressure ratio required for winter heating.
  • a high-pressure compressor can be used to compress the refrigerant alone, which is also conducive to better matching the flow and pressure ratio, avoiding the "small horse pulling a big cart” phenomenon, and also conducive to improving the operating stability of the heat pump system.
  • the refrigerant circulation loop of the heat pump system is equipped with a flasher.
  • air can be supplied from the middle of the two compressors.
  • air can be supplied from the air supply port of the running high-pressure compressor.
  • the pressure ratio is balanced by switching the air supply, thus achieving efficient operation in dual working conditions.
  • the flash unit is installed on the condenser, the low-pressure compressor is installed on the evaporator, and the high-pressure compressor and the flash unit are installed on the condenser, which is conducive to the compact overall structure of the heat pump system and saves the installation area of the project.
  • the two compressors are turned on at the same time, and the adjustable inlet guide vanes of the low-pressure compressor are kept fully open.
  • the supply air pressure can be regulated by adjusting the opening of the adjustable inlet guide vane of the high-pressure compressor. This is because the exhaust pressure of the low-pressure compressor can be controlled by adjusting the opening of the adjustable inlet guide vane of the high-pressure compressor, thereby affecting the supply air pressure.
  • the opening of the adjustable inlet guide vane of the high-pressure compressor is closed to increase the back pressure of the low-pressure compressor.
  • the supply air needs to overcome this back pressure to send the gas into the high-pressure compressor.
  • the opening of the adjustable inlet guide vane of the high-pressure compressor is increased to reduce the back pressure of the low-pressure compressor, and the supply air pressure is appropriately reduced. Therefore, the supply air pressure can be intervened by adjusting the opening of the adjustable inlet guide vane of the high-pressure compressor.
  • the user's cooling mode needs are met by turning on the high-pressure compressor alone.
  • the adjustable inlet guide vanes of the high-pressure compressor can be used to adjust the flow rate to meet the user's different load requirements.
  • the two compressors use fixed-speed compressors and utilize fixed-speed compatible pneumatic technology.
  • the high-pressure stage compressor is designed according to the cooling mode, and the low-pressure stage compressor is designed according to the heating mode.
  • the pressure ratio is redistributed by adjusting the opening of the adjustable inlet guide vanes of the high-pressure stage compressor, which is conducive to achieving a large pressure ratio in the heating mode and high-efficiency operation in the cooling mode.
  • the low-pressure compressor adopts a single-stage theoretical cycle design without air supplementation
  • the high-pressure compressor adopts a two-stage theoretical cycle design with air supplementation, which is conducive to air supplementation and enthalpy increase when the working condition is switched to improve the operating efficiency of the cooling mode.
  • the working condition is switched through the air supplement valve, and the pressure of the flasher is controlled by adjusting the adjustable inlet guide vane opening of the high-pressure compressor, which is conducive to the redistribution of the pressure ratio of the low-pressure compressor and the high-pressure compressor.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Compression-Type Refrigeration Machines With Reversible Cycles (AREA)

Abstract

La présente invention concerne un système de pompe à chaleur et un procédé de commande pour système de pompe à chaleur. Une boucle de circulation de fluide frigorigène du système de pompe à chaleur comprend un tuyau de fluide frigorigène principal (13), un évaporateur (3), un dispositif de compression, un condenseur (4) et un dispositif d'étranglement, le système de pompe à chaleur ayant un mode de refroidissement et un mode de chauffage. Le dispositif de compression comprend un compresseur à étage basse pression (1) et un compresseur à étage haute pression (2). La boucle de circulation de fluide frigorigène comprend, en outre, un dispositif de commutation, et le dispositif de commutation est conçu pour permettre à la boucle de circulation de fluide frigorigène d'avoir un état de fonctionnement de compresseur unique, dans lequel le compresseur à étage haute pression (2) comprime un fluide frigorigène seul dans le mode de refroidissement, et un état de fonctionnement à double compresseur, dans lequel le compresseur à étage basse pression (1) et le compresseur à étage haute pression (2) compriment le fluide frigorigène en série dans le mode de chauffage. Dans l'état de fonctionnement à compresseur unique, le rapport de pression du compresseur à étage haute pression (2) est conçu pour satisfaire le rapport de pression requis par le dispositif de compression du système de pompe à chaleur dans le mode de refroidissement ; dans l'état de fonctionnement à double compresseur, le rapport de pression du compresseur à étage basse pression (1) est conçu pour satisfaire, conjointement avec celui du compresseur à étage haute pression (2), le rapport de pression requis par le dispositif de compression du système de pompe à chaleur dans le mode de chauffage.
PCT/CN2023/119728 2022-11-07 2023-09-19 Système de pompe à chaleur et procédé de commande pour système de pompe à chaleur WO2024098966A1 (fr)

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Publication number Priority date Publication date Assignee Title
CN115560493A (zh) * 2022-11-07 2023-01-03 珠海格力电器股份有限公司 热泵系统和热泵系统的控制方法

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JP2007010282A (ja) * 2005-07-04 2007-01-18 Hitachi Ltd 二段圧縮式冷凍サイクル装置
JP2007147244A (ja) * 2005-11-30 2007-06-14 Daikin Ind Ltd 冷凍装置
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CN113776219A (zh) * 2021-08-20 2021-12-10 清华大学 适用于严寒地区的空气源热泵、空调器及控制方法
CN115560493A (zh) * 2022-11-07 2023-01-03 珠海格力电器股份有限公司 热泵系统和热泵系统的控制方法
CN218442842U (zh) * 2022-11-07 2023-02-03 珠海格力电器股份有限公司 热泵系统

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000346474A (ja) * 1999-06-03 2000-12-15 Daikin Ind Ltd 冷凍装置
JP2007010282A (ja) * 2005-07-04 2007-01-18 Hitachi Ltd 二段圧縮式冷凍サイクル装置
JP2007147244A (ja) * 2005-11-30 2007-06-14 Daikin Ind Ltd 冷凍装置
CN102466361A (zh) * 2010-11-08 2012-05-23 Lg电子株式会社 空气调节器
CN104501437A (zh) * 2014-11-25 2015-04-08 珠海格力电器股份有限公司 热泵系统及其运行方法
CN113776219A (zh) * 2021-08-20 2021-12-10 清华大学 适用于严寒地区的空气源热泵、空调器及控制方法
CN115560493A (zh) * 2022-11-07 2023-01-03 珠海格力电器股份有限公司 热泵系统和热泵系统的控制方法
CN218442842U (zh) * 2022-11-07 2023-02-03 珠海格力电器股份有限公司 热泵系统

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