WO2023012960A1 - 冷凍サイクル装置、及び冷凍サイクル装置の制御方法 - Google Patents

冷凍サイクル装置、及び冷凍サイクル装置の制御方法 Download PDF

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Publication number
WO2023012960A1
WO2023012960A1 PCT/JP2021/029052 JP2021029052W WO2023012960A1 WO 2023012960 A1 WO2023012960 A1 WO 2023012960A1 JP 2021029052 W JP2021029052 W JP 2021029052W WO 2023012960 A1 WO2023012960 A1 WO 2023012960A1
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Prior art keywords
side refrigerant
low
pressure
refrigerant
low temperature
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PCT/JP2021/029052
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English (en)
French (fr)
Japanese (ja)
Inventor
智隆 石川
拓未 西山
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三菱電機株式会社
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Priority to EP21952785.0A priority Critical patent/EP4382827A4/en
Priority to CN202180101065.3A priority patent/CN117716185A/zh
Priority to JP2023539474A priority patent/JPWO2023012960A1/ja
Priority to PCT/JP2021/029052 priority patent/WO2023012960A1/ja
Publication of WO2023012960A1 publication Critical patent/WO2023012960A1/ja

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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
    • F25B1/00—Compression machines, plants or systems with non-reversible cycle
    • F25B1/005—Compression machines, plants or systems with non-reversible cycle of the single unit type
    • 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
    • F25B49/005—Arrangement or mounting of control or safety devices of safety devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • 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
    • F25B49/022—Compressor control 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
    • F25B7/00—Compression machines, plants or systems, with cascade operation, i.e. with two or more circuits, the heat from the condenser of one circuit being absorbed by the evaporator of the next circuit
    • 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
    • F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
    • F25B9/002—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant
    • F25B9/006—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant the refrigerant containing more than one component
    • 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
    • F25B2400/19—Pumping down refrigerant from one part of the cycle to another part of the cycle, e.g. when the cycle is changed from cooling to heating, or before a defrost cycle is started
    • 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
    • F25B2400/22—Refrigeration systems for supermarkets
    • 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
    • F25B25/00—Machines, plants or systems, using a combination of modes of operation covered by two or more of the groups F25B1/00 - F25B23/00
    • F25B25/005—Machines, plants or systems, using a combination of modes of operation covered by two or more of the groups F25B1/00 - F25B23/00 using primary and secondary systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2500/00—Problems to be solved
    • F25B2500/07—Exceeding a certain pressure value in a refrigeration component or cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2500/00—Problems to be solved
    • F25B2500/27—Problems to be solved characterised by the stop of the refrigeration cycle
    • 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
    • F25B2600/00—Control issues
    • F25B2600/02—Compressor control
    • F25B2600/025—Compressor control by controlling speed
    • F25B2600/0253—Compressor control by controlling speed with variable speed
    • 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
    • F25B2600/00—Control issues
    • F25B2600/11—Fan speed control
    • F25B2600/111—Fan speed control of condenser fans
    • 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
    • F25B2600/00—Control issues
    • F25B2600/25—Control of valves
    • F25B2600/2513—Expansion valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/25—Control of valves
    • F25B2600/2525—Pressure relief valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/19—Pressures
    • F25B2700/193—Pressures of the compressor
    • F25B2700/1931—Discharge pressures
    • 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
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/19—Pressures
    • F25B2700/195—Pressures of the condenser
    • 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
    • F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat
    • F25B43/006—Accumulators

Definitions

  • the present disclosure relates to a refrigeration cycle device having a dual refrigeration cycle and a control method for the refrigeration cycle device.
  • a low temperature circuit in which a low temperature side refrigerant circulates a high temperature circuit in which a high temperature side refrigerant circulates, and a low temperature side refrigerant and a high temperature side refrigerant are heated.
  • a refrigeration system with a replaceable cascade condenser is known (for example, Patent Document 1).
  • a receiver for storing surplus refrigerant is provided in the lower circuit, and a non-azeotropic refrigerant mixture is used as the refrigerant in the lower circuit.
  • a non-azeotropic refrigerant mixture is used as the refrigerant in the lower circuit.
  • the gas of the refrigerant with a low boiling point stays in the receiver, which may cause the composition of the refrigerant circulating in the low-level circuit to fluctuate.
  • the refrigerants contained in the non-azeotropic refrigerant mixture if the refrigerant with a high boiling point is flammable, the compositional fluctuation of the refrigerant increases the flammability of the refrigerant circulating in the low-level circuit, and the risk of flammability when the refrigerant leaks. increases.
  • the present disclosure is intended to solve the above-described problems, and aims to provide a refrigeration cycle device and a control method for the refrigeration cycle device that can suppress fluctuations in the composition of refrigerant.
  • a refrigeration cycle device includes a first compressor, a condenser, a first pressure reducing device, and a cascade heat exchanger, and includes a high-level circuit in which a high-level side refrigerant circulates, a second compressor, and a cascade heat exchange.
  • a low temperature circuit in which low temperature side refrigerant circulates, and the cascade heat exchanger heat-exchanges the high temperature side refrigerant and the low temperature side refrigerant.
  • the low temperature side refrigerant is a non-azeotropic mixed refrigerant, and the high pressure of the low temperature side refrigerant circulating in the low temperature circuit is maintained at or below the pressure at which the low temperature side refrigerant can maintain nonflammability.
  • a control method for a refrigeration cycle device includes a first compressor, a condenser, a first pressure reducing device, and a cascade heat exchanger, a higher circuit in which a higher side refrigerant circulates, a second compressor,
  • a control method for a refrigeration cycle device comprising a cascade heat exchanger, a receiver, a second pressure reducing device, and an evaporator, and a low-level circuit in which low-level side refrigerant circulates, wherein the cascade heat exchanger comprises a high-level circuit
  • the low temperature side refrigerant is a non-azeotropic mixed refrigerant, and the low temperature side refrigerant is nonflammable when the high pressure of the low temperature side refrigerant circulating in the low temperature circuit is applied. Keep the pressure below the pressure that can maintain sexuality.
  • the high-pressure pressure of the low-side refrigerant circulating in the low-side circuit is maintained at or below the pressure at which the low-side refrigerant can maintain nonflammability, thereby suppressing fluctuations in the composition of the refrigerant.
  • FIG. 1 is a schematic configuration diagram of a refrigeration cycle apparatus according to Embodiment 1;
  • FIG. 4 is a graph showing the relationship between the combustibility of the low-side refrigerant and the high pressure PH .
  • Embodiment 1 A refrigeration cycle apparatus 100 according to Embodiment 1 will be described.
  • the refrigerating cycle device 100 includes dual refrigerating cycles that independently circulate refrigerant, and is used for refrigeration, refrigeration, hot water supply, air conditioning, and the like.
  • a case where the refrigerating cycle device 100 is used as a refrigerating device that cools a freezer compartment or the like will be described as an example.
  • FIG. 1 is a schematic configuration diagram of a refrigeration cycle device 100 according to Embodiment 1.
  • the refrigeration cycle apparatus 100 of this embodiment includes a high-level circuit 1 , a low-level circuit 2 , and a control device 3 .
  • the high temperature circuit 1 is a high temperature circuit in which the high temperature side refrigerant circulates
  • the low temperature circuit 2 is a low temperature circuit in which the low temperature side refrigerant whose boiling point is lower than that of the high temperature side refrigerant circulates.
  • the high-level circuit 1 and the low-level circuit 2 have a cascade heat exchanger 14 in common, and the high-level side refrigerant circulating in the high-level circuit 1 and the low-level side circulating in the low-level circuit 2 are provided by the cascade heat exchanger 14. Heat exchange with the refrigerant takes place.
  • the high-level circuit 1 includes a first compressor 11, a condenser 12, a first pressure reducing device 13, and a cascade heat exchanger 14.
  • the first compressor 11, the condenser 12, the first pressure reducing device 13, and the cascade heat exchanger 14 are connected in this order by piping.
  • the high-voltage side refrigerant circulating in the high-voltage circuit 1 is, for example, an HFC-based refrigerant such as R134a, R32 or R410A, or an HFO-based refrigerant such as HFO-1234yf, or a mixed refrigerant.
  • the first compressor 11 is, for example, a capacity-controllable inverter type compressor.
  • the first compressor 11 circulates the high temperature side refrigerant in the high temperature circuit 1 by drawing in the high temperature side refrigerant, compressing it, and discharging it in a high temperature and high pressure state.
  • the condenser 12 is, for example, a fin-tube heat exchanger.
  • the condenser 12 exchanges heat between the air and the high temperature side refrigerant, and condenses and liquefies the high temperature side refrigerant.
  • the refrigeration cycle device 100 includes a first fan 15 for supplying air to the condenser 12 .
  • the first fan 15 is, for example, a propeller fan or a cross-flow fan that can adjust the air volume.
  • the condenser 12 may be, for example, a plate-type heat exchanger that exchanges heat between water or brine and the high-temperature side refrigerant. In this case, the first fan 15 may be omitted.
  • the first decompression device 13 is, for example, an electronic expansion valve whose opening can be controlled.
  • the first decompression device 13 is connected to the condenser 12 and decompresses and expands the high-side refrigerant flowing out of the condenser 12 .
  • the first decompression device 13 may be a capillary tube or a temperature-sensitive expansion valve.
  • the cascade heat exchanger 14 is, for example, a plate heat exchanger.
  • the cascade heat exchanger 14 includes a high-level side flow path 141 connected to the high-level circuit 1 and a low-level side flow path 142 connected to the low-level circuit 2 . Heat exchange is performed between the source side refrigerant and the low temperature side refrigerant flowing through the low temperature side flow path 142 .
  • the high temperature side flow path 141 of the cascade heat exchanger 14 functions as an evaporator to evaporate and gasify the high temperature side refrigerant.
  • the low temperature side flow path 142 of the cascade heat exchanger 14 functions as a condenser to condense and liquefy the low temperature side refrigerant.
  • the low-level circuit 2 includes a second compressor 21 , a cascade heat exchanger 14 , a receiver 22 , a second pressure reducing device 23 and an evaporator 24 .
  • the second compressor 21, the cascade heat exchanger 14, the receiver 22, the second pressure reducing device 23, and the evaporator 24 are connected by piping in this order.
  • the low temperature side refrigerant circulating in the low temperature side circuit 2 is a non-azeotropic mixed refrigerant having a lower boiling point than the high temperature side refrigerant. By using a non-azeotropic refrigerant mixture, it is possible to obtain a low evaporation temperature that cannot be obtained with a single refrigerant.
  • a non-azeotropic mixed refrigerant containing CO 2 and R290 (propane) is used as the low gas side refrigerant.
  • CO2 is a low boiling point refrigerant and R290 is a high boiling point refrigerant with a higher boiling point than CO2 .
  • Using natural refrigerants such as CO2 and R290 can reduce the environmental impact.
  • mixing CO2 into the low temperature side refrigerant improves the cooling capacity, and mixing R290 improves the COP and lowers the triple point of CO2 , enabling low-temperature use.
  • the second compressor 21 is, for example, a capacity-controllable inverter type compressor.
  • the second compressor 21 draws in the low temperature side refrigerant, compresses it, and discharges it in a high temperature and high pressure state, thereby circulating the low temperature side refrigerant in the low temperature circuit 2 .
  • the receiver 22 is arranged between the cascade heat exchanger 14 and the second pressure reducing device 23 and temporarily stores the low temperature side refrigerant flowing out of the low temperature side flow path 142 of the cascade heat exchanger 14 .
  • the receiver 22 stores surplus refrigerant caused by fluctuations in the cooling load.
  • the second decompression device 23 is, for example, an electronic expansion valve whose opening can be controlled.
  • the second decompression device 23 is connected to the refrigerant outlet of the receiver 22 and decompresses the low-side refrigerant flowing out of the receiver 22 to expand it.
  • the second decompression device 23 may be a capillary tube or a temperature-sensitive expansion valve.
  • the evaporator 24 is, for example, a fin-tube heat exchanger.
  • the evaporator 24 exchanges heat between the air and the low-side refrigerant to evaporate and gasify the low-side refrigerant.
  • the refrigerating cycle device 100 includes a second fan 25 for supplying air to the evaporator 24 .
  • the second fan 25 is, for example, a propeller fan or a cross-flow fan capable of adjusting the air volume.
  • the evaporator 24 may be a plate heat exchanger or the like that exchanges heat between water or brine and the low temperature side refrigerant, for example. In this case, the second fan 25 may be omitted.
  • the refrigeration cycle device 100 also includes a pressure sensor 26 that detects the high pressure PH of the low temperature side refrigerant circulating in the low temperature circuit 2 .
  • the pressure sensor 26 is provided in a pipe connecting the low-side flow path 142 of the cascade heat exchanger 14 and the receiver 22 .
  • the pressure sensor 26 can be provided at any position on the high-pressure side of the low-voltage circuit 2 , that is, between the discharge port of the second compressor 21 and the refrigerant inlet of the second pressure reducing device 23 .
  • the high pressure PH of the low-side refrigerant detected by the pressure sensor 26 is transmitted to the control device 3 .
  • a sensor for detecting another physical quantity (for example, the condensation temperature) that can be converted to the high pressure PH of the low-side refrigerant may be provided and converted to the high pressure PH by the control device 3. good.
  • the refrigerating cycle device 100 detects the temperature or pressure of the refrigerant at any location in the outdoor temperature sensor that detects the outdoor temperature, the indoor temperature sensor that detects the temperature in the freezer compartment, and the high-level circuit 1 and the low-level circuit 2.
  • Various sensors such as sensors may be further provided.
  • the control device 3 controls the overall operation of the refrigeration cycle device 100 .
  • the control device 3 is composed of a processing device having a memory for storing data and programs necessary for control and a CPU for executing the programs, dedicated hardware such as ASIC or FPGA, or both.
  • the control device 3 of the present embodiment controls the high temperature circuit 1 based on the high pressure PH of the low temperature side refrigerant detected by the pressure sensor 26 .
  • the control device 3 controls each device of the high-level circuit 1 and the low-level circuit 2, and the first fan 15 and the second fan 25 based on the information received from various sensors and the operation contents instructed by the user. do.
  • the operation of the refrigeration cycle device 100 of the present embodiment will be described based on the flow of refrigerant circulating through each refrigerant circuit.
  • the operation of the high-level circuit 1 will be described.
  • the first compressor 11 of the high-voltage circuit 1 sucks the high-voltage side refrigerant, compresses it, and discharges it in a high-temperature, high-pressure state.
  • the high pressure side refrigerant discharged from the first compressor 11 flows into the condenser 12 .
  • the condenser 12 exchanges heat between the air supplied from the first fan 15 and the high temperature side refrigerant to condense and liquefy the high temperature side refrigerant.
  • the high-side refrigerant condensed and liquefied in the condenser 12 passes through the first decompression device 13 .
  • the first decompression device 13 decompresses the condensed and liquefied high-side refrigerant.
  • the high temperature side refrigerant decompressed by the first pressure reducing device 13 flows into the high temperature side flow path 141 of the cascade heat exchanger 14 .
  • the high temperature refrigerant that has flowed into the high temperature flow passage 141 is heat-exchanged with the low temperature refrigerant flowing through the low temperature flow passage 142 of the cascade heat exchanger 14, and is evaporatively gasified.
  • the high-pressure side refrigerant evaporated and gasified in the cascade heat exchanger 14 is sucked into the first compressor 11 again.
  • the second compressor 21 of the low temperature circuit 2 sucks the low temperature side refrigerant, compresses it, and discharges it in a high temperature and high pressure state.
  • the low temperature side refrigerant discharged from the second compressor 21 flows into the low temperature side flow path 142 of the cascade heat exchanger 14 .
  • the low temperature refrigerant that has flowed into the low temperature flow path 142 is heat-exchanged with the high temperature side refrigerant that flows through the high temperature flow path 141 of the cascade heat exchanger 14, and is condensed and liquefied.
  • the low-side refrigerant condensed and liquefied in the cascade heat exchanger 14 flows into the receiver 22 .
  • the low-side refrigerant that has flowed out of the receiver 22 passes through the second pressure reducing device 23 .
  • the second decompression device 23 decompresses the low-side refrigerant.
  • the low-side refrigerant decompressed by the second decompression device 23 flows into the evaporator 24 .
  • the evaporator 24 exchanges heat between the air supplied from the second fan 25 and the low temperature side refrigerant to evaporate the low temperature side refrigerant.
  • the freezer compartment is cooled by the low-side refrigerant absorbing heat from the air.
  • the low-side refrigerant evaporated and gasified by the evaporator 24 is sucked into the second compressor 21 again.
  • the receiver 22 of the low-level circuit 2 stores excess liquid refrigerant generated according to the operating conditions or load conditions of the refrigeration cycle device 100 .
  • the refrigerant with a low boiling point becomes gas and stays in the receiver 22, flows out from the receiver 22, and circulates in the low temperature circuit 2.
  • Composition fluctuates.
  • a non-azeotropic mixed refrigerant of CO 2 and R290 is used as the low-side refrigerant as in the present embodiment, CO 2 having a boiling point lower than that of R290 stays in the receiver 22 as gas.
  • the ratio of R290 which is a combustible refrigerant, increases in the circulation composition of the low pressure side refrigerant.
  • the flammability of the low-voltage side refrigerant circulating in the low-voltage circuit 2 increases, increasing the risk of flammability when the refrigerant leaks.
  • FIG. 2 is a graph showing the relationship between the combustibility of the low-side refrigerant and the high pressure PH .
  • the graph of FIG. 2 is a graph when the low-side refrigerant is a non-azeotropic refrigerant mixture and the refrigerant with the higher boiling point is combustible, as in the present embodiment. As shown in FIG. 2, the higher the high pressure PH of the low-side refrigerant, the higher the combustibility.
  • the threshold PT is uniquely determined by the physical properties of the refrigerant that constitutes the low-concentration side refrigerant.
  • the threshold PT is set in advance according to the low-concentration side refrigerant and stored in the controller 3 .
  • the control device 3 controls the capacity of the high-voltage circuit 1 so that the high pressure PH of the low-voltage side refrigerant detected by the pressure sensor 26 is equal to or lower than the threshold value PT .
  • FIG. 3 is a flow chart showing the operation of the refrigeration cycle apparatus 100 according to Embodiment 1.
  • the control device 3 drives the first compressor 11 and the second compressor 21 (S1). As a result, the high temperature side refrigerant circulates in the high temperature circuit 1, the low temperature side refrigerant circulates in the low temperature circuit 2, and the freezer compartment is cooled.
  • the control device 3 determines whether or not the high-pressure pressure PH of the low-side refrigerant detected by the pressure sensor 26 is equal to or less than the threshold value PT (S3).
  • the threshold value PT S3: YES
  • the control device 3 increases the capacity of the high-voltage circuit 1 (S4).
  • control device 3 increases the operating frequency of the first compressor 11 of the high-level circuit 1 .
  • the control device 3 may increase the operating frequency of the first compressor 11 by a predetermined constant value, or may increase the operating frequency of the first compressor 11 according to the difference between the high pressure PH of the low-side refrigerant and the threshold value PT . may be increased by
  • the temperature of the high temperature side refrigerant flowing through the high temperature side flow path 141 of the cascade heat exchanger 14 is lowered.
  • the temperature of the low temperature side refrigerant heat-exchanged with the high temperature side refrigerant in the cascade heat exchanger 14 decreases, and the high pressure PH of the low temperature side refrigerant decreases.
  • the high-pressure pressure PH of the low-side refrigerant decreases, the gas density in the receiver 22 decreases and the mass of the gas refrigerant in the receiver 22 decreases.
  • the high-pressure pressure PH of the low-side refrigerant decreases, the amount of low-boiling-point refrigerant gas remaining in the receiver 22 decreases, and the amount of low-side refrigerant flowing out of the receiver 22 and circulating in the low-side circuit 2 increases. Compositional fluctuations can be minimized.
  • the control device 3 determines whether or not to stop the operation of the refrigeration cycle device 100 according to an instruction from the user or the like (S5). If the operation is not to be stopped (S5: NO), the process returns to step S2 and repeats the subsequent processes. On the other hand, when stopping the operation (S5: YES), the first compressor 11 and the second compressor 21 are stopped (S6). As a result, the high-pressure pressure PH of the low-concentration-side refrigerant is maintained at or below the threshold PT during operation of the refrigeration cycle device 100 .
  • the high-voltage circuit 1 controls the high-voltage circuit 1 so that the high-pressure pressure PH of the low-voltage side refrigerant is equal to or lower than the threshold value PT at which the low-voltage side refrigerant can maintain nonflammability. be done. As a result, it is possible to suppress the composition fluctuation of the low-voltage side refrigerant that flows out from the receiver 22 and circulates in the low-voltage circuit 2 .
  • FIG. 4 is a flow chart showing the operation of the refrigeration cycle apparatus 100 according to the second embodiment. This embodiment differs from the first embodiment in the operation of refrigeration cycle apparatus 100 after the stop instruction.
  • the configuration of the refrigeration cycle device 100 is the same as that of the first embodiment.
  • step S1 to S4 the operations during operation of the refrigeration cycle device 100 (steps S1 to S4) are the same as in the first embodiment.
  • the control device 3 determines whether or not to stop the operation of the refrigeration cycle device 100 according to an instruction from the user or the like (S5). If the operation is not to be stopped (S5: NO), the process returns to step S2 and repeats the subsequent processes.
  • the control device 3 performs pump-down operation in the low-level circuit 2 (S11).
  • the control device 3 fully closes the second pressure reducing device 23 and continues the operation of the second compressor 21 . Since the second decompression device 23 located downstream of the receiver 22 is closed, the low temperature side refrigerant in the low temperature circuit 2 is collected in the low temperature side flow path 142 of the cascade heat exchanger 14 and the receiver 22. be done. After that, the control device 3 stops the second compressor 21 (S12). As a result, circulation of the low-voltage side refrigerant in the low-voltage circuit 2 is stopped.
  • a solenoid valve may be provided between the refrigerant outlet of the receiver 22 and the second pressure reducing device 23, and the pump-down operation may be performed by closing the solenoid valve.
  • a pressure sensor for detecting the low-pressure pressure of the low-voltage side refrigerant is provided between the low-pressure side of the low-voltage circuit 2, that is, the refrigerant outlet of the second pressure reducing device 23 and the suction port of the second compressor 21.
  • the second compressor 21 may be stopped when the low pressure of the refrigerant becomes lower than the atmospheric pressure.
  • the control device 3 determines whether or not the high-pressure pressure PH of the low-side refrigerant detected by the pressure sensor 26 is equal to or less than the threshold value PT (S14). If the high-pressure pressure PH of the low-voltage side refrigerant is equal to or less than the threshold value PT (S14: YES), the process proceeds to step S16 while maintaining the performance of the high-voltage circuit 1 . On the other hand, when the high pressure PH of the low-side refrigerant is greater than the threshold PT (S14: NO), the control device 3 increases the capacity of the high-voltage circuit 1 (S15). Specifically, as in the first embodiment, the control device 3 increases the operating frequency of the first compressor 11 of the high-level circuit 1 .
  • the low boiling point refrigerant gasifies and the composition of the liquid refrigerant in the receiver 22 may fluctuate.
  • CO2 which is a low-boiling-point refrigerant
  • R290 which is a combustible refrigerant
  • the high-voltage circuit is controlled so that the high-pressure pressure PH of the low-voltage side refrigerant is equal to or lower than the threshold PT at which the low-voltage side refrigerant can maintain nonflammability. 1 is controlled.
  • the temperature of the low temperature side refrigerant staying in the low temperature side flow path 142 of the cascade heat exchanger 14 is lowered, and the high pressure PH of the low temperature side refrigerant is lowered.
  • the low-side refrigerant whose temperature has decreased in the cascade heat exchanger 14 flows into the receiver 22 through natural convection so as to maintain the temperature and pressure balance, thereby decreasing the gas density of the receiver 22.
  • the mass of the gas refrigerant in the receiver 22 is reduced.
  • the amount of low-boiling-point refrigerant (CO 2 ) gas refrigerant in the receiver 22 is reduced, and fluctuations in the composition of the liquid refrigerant in the receiver 22 can be minimized.
  • the control device 3 determines whether or not to start the operation of the refrigeration cycle device 100 according to an instruction from the user (S16). If the operation is not to be started (S16: NO), the process returns to step S13 and the subsequent processes are repeated. If the operation is to be started (S16: YES), the process proceeds to step S1, and the second compressor 21 is driven to circulate the low temperature side refrigerant in the low temperature circuit 2.
  • the refrigerating cycle device 100 of the present embodiment in addition to the same effects as in the first embodiment, even when the refrigerating cycle device 100 is stopped, fluctuations in the composition of the liquid refrigerant remaining in the receiver 22 can be suppressed. can be done. As a result, even when a non-azeotropic mixed refrigerant containing a flammable refrigerant is used as the low-side refrigerant, an increase in the risk of flammability when refrigerant leaks from the receiver 22 can be suppressed.
  • the low-side refrigerant is not limited to a non-azeotropic refrigerant mixture of CO 2 and R290, and may be other non-azeotropic refrigerant mixtures.
  • the low-side refrigerant is a non-azeotropic mixed refrigerant containing CO 2 and a combustible refrigerant, the effects of the above embodiment can be particularly obtained.
  • the controller 3 is configured to control the entire refrigeration cycle apparatus 100.
  • the operation of the original circuit 2 may be individually controlled.
  • the present invention is not limited to this.
  • the control device 3 increases the opening degree of the first decompression device 13 and the rotation speed of the first fan 15 to Increases 1 ability.
  • the high-voltage circuit 1 is controlled according to the high pressure PH of the low-voltage side refrigerant detected by the pressure sensor 26, but the present invention is not limited to this.
  • the control device 3 may control the high temperature circuit 1 according to the condensation temperature of the low temperature side refrigerant corresponding to the high pressure PH of the low temperature side refrigerant.
  • the control device 3 controls the high-voltage circuit 1 in accordance with the cooling load of the low-voltage circuit 2 to set the high-pressure pressure PH of the low-voltage side refrigerant to a pressure value at which the low-voltage side refrigerant maintains nonflammability. The following may be used.
  • the cooling load of the low-order circuit 2 is determined based on the room temperature of the freezer compartment or the like, which is to be cooled, for example.
  • the control device 3 increases the capacity of the high-level circuit 1 when the cooling load of the low-level circuit 2 increases, and increases the capacity of the high-level circuit 1 when the cooling load of the low-level circuit 2 decreases. reduce the ability of As a result, even if the high pressure PH of the low temperature side refrigerant rises due to an increase in the cooling load of the low temperature circuit 2, the high pressure PH of the low temperature side refrigerant is increased by increasing the capacity of the high temperature circuit 1. can be lowered.
  • the high pressure PH of the low temperature side refrigerant can be maintained below the pressure value at which the low temperature side refrigerant maintains non-flammability.
  • the pressure sensor 26 may be omitted, or control based on the high pressure PH of the low-side refrigerant detected by the pressure sensor 26 may be combined.
  • FIG. 5 is a schematic configuration diagram of a refrigeration cycle apparatus 100A according to a modification.
  • the refrigeration cycle device 100A includes a pressure relief device 27.
  • a pressure relief device 27 is provided in the refrigerant pipe or receiver 22 on the high pressure side of the low-voltage circuit 2 .
  • the pressure relief device 27 is a pressure relief valve or a fusible plug, and when the high-pressure pressure PH or the condensation temperature of the low-side refrigerant becomes equal to or higher than the threshold PT , the valve or the plug is opened to release the gas refrigerant. is discharged to the outside, and the high-pressure pressure PH of the low-concentration side refrigerant is lowered.
  • the threshold value PT is a pressure value or temperature at which the low-side refrigerant can maintain nonflammability, as in the above embodiment.
  • the high-pressure pressure PH of the low-side refrigerant can be maintained at or below a pressure value at which the low-side refrigerant can maintain nonflammability.
  • the control of the high-voltage circuit 1 by the high pressure PH of the low-voltage side refrigerant detected by the pressure sensor 26 or the cooling load may be omitted, or these controls may be combined. good too.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Compression-Type Refrigeration Machines With Reversible Cycles (AREA)
  • Devices That Are Associated With Refrigeration Equipment (AREA)
PCT/JP2021/029052 2021-08-05 2021-08-05 冷凍サイクル装置、及び冷凍サイクル装置の制御方法 WO2023012960A1 (ja)

Priority Applications (4)

Application Number Priority Date Filing Date Title
EP21952785.0A EP4382827A4 (en) 2021-08-05 2021-08-05 REFRIGERATION CIRCUIT DEVICE AND REFRIGERATION CIRCUIT CONTROL METHOD
CN202180101065.3A CN117716185A (zh) 2021-08-05 2021-08-05 制冷循环装置和制冷循环装置的控制方法
JP2023539474A JPWO2023012960A1 (zh) 2021-08-05 2021-08-05
PCT/JP2021/029052 WO2023012960A1 (ja) 2021-08-05 2021-08-05 冷凍サイクル装置、及び冷凍サイクル装置の制御方法

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JP2001019944A (ja) * 1999-07-09 2001-01-23 Matsushita Electric Ind Co Ltd 低温作動流体とそれを用いた冷凍サイクル装置
JP2008215672A (ja) * 2007-03-01 2008-09-18 Mac:Kk 可燃性冷媒ガスを使用する冷凍サイクルの残留ガス回収方法及びその装置
JP2012087978A (ja) * 2010-10-19 2012-05-10 Mitsubishi Electric Corp 冷凍装置
JP2012112615A (ja) * 2010-11-26 2012-06-14 Mitsubishi Electric Corp 二元冷凍装置
WO2014030236A1 (ja) 2012-08-23 2014-02-27 三菱電機株式会社 冷凍装置
WO2014045400A1 (ja) * 2012-09-21 2014-03-27 三菱電機株式会社 冷凍装置及びその制御方法
WO2015045354A1 (ja) * 2013-09-27 2015-04-02 パナソニックヘルスケア株式会社 冷凍装置
WO2015140873A1 (ja) * 2014-03-17 2015-09-24 三菱電機株式会社 冷凍装置、及び、冷凍装置の制御方法
WO2018198203A1 (ja) * 2017-04-25 2018-11-01 三菱電機株式会社 二元冷凍装置

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JP2001019944A (ja) * 1999-07-09 2001-01-23 Matsushita Electric Ind Co Ltd 低温作動流体とそれを用いた冷凍サイクル装置
JP2008215672A (ja) * 2007-03-01 2008-09-18 Mac:Kk 可燃性冷媒ガスを使用する冷凍サイクルの残留ガス回収方法及びその装置
JP2012087978A (ja) * 2010-10-19 2012-05-10 Mitsubishi Electric Corp 冷凍装置
JP2012112615A (ja) * 2010-11-26 2012-06-14 Mitsubishi Electric Corp 二元冷凍装置
WO2014030236A1 (ja) 2012-08-23 2014-02-27 三菱電機株式会社 冷凍装置
WO2014045400A1 (ja) * 2012-09-21 2014-03-27 三菱電機株式会社 冷凍装置及びその制御方法
WO2015045354A1 (ja) * 2013-09-27 2015-04-02 パナソニックヘルスケア株式会社 冷凍装置
WO2015140873A1 (ja) * 2014-03-17 2015-09-24 三菱電機株式会社 冷凍装置、及び、冷凍装置の制御方法
WO2018198203A1 (ja) * 2017-04-25 2018-11-01 三菱電機株式会社 二元冷凍装置

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See also references of EP4382827A4

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CN117716185A (zh) 2024-03-15
EP4382827A1 (en) 2024-06-12

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