WO2020071299A1 - 冷凍サイクル装置 - Google Patents
冷凍サイクル装置Info
- Publication number
- WO2020071299A1 WO2020071299A1 PCT/JP2019/038451 JP2019038451W WO2020071299A1 WO 2020071299 A1 WO2020071299 A1 WO 2020071299A1 JP 2019038451 W JP2019038451 W JP 2019038451W WO 2020071299 A1 WO2020071299 A1 WO 2020071299A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- main
- sub
- refrigerant
- heat exchanger
- side heat
- Prior art date
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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
- 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
- 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
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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
- F25B40/00—Subcoolers, desuperheaters or superheaters
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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
- F25B40/00—Subcoolers, desuperheaters or superheaters
- F25B40/02—Subcoolers
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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
- 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
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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
- F25B2313/006—Compression machines, plants or systems with reversible cycle not otherwise provided for two 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
- F25B2313/009—Compression machines, plants or systems with reversible cycle not otherwise provided for indoor unit in circulation with outdoor unit in first operation mode, indoor unit in circulation with an other heat exchanger in second operation mode or outdoor unit in circulation with an other heat exchanger in third operation mode
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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
- F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
- F25B2313/025—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple outdoor units
- F25B2313/0252—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple outdoor units with bypasses
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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
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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
- F25B2600/00—Control issues
- F25B2600/25—Control of valves
- F25B2600/2509—Economiser 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
- F25B2700/00—Sensing or detecting of parameters; Sensors therefor
- F25B2700/19—Pressures
- F25B2700/193—Pressures of the compressor
- F25B2700/1931—Discharge pressures
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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
- F25B2700/00—Sensing or detecting of parameters; Sensors therefor
- F25B2700/19—Pressures
- F25B2700/193—Pressures of the compressor
- F25B2700/1933—Suction pressures
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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
- F25B2700/00—Sensing or detecting of parameters; Sensors therefor
- F25B2700/21—Temperatures
- F25B2700/2115—Temperatures of a compressor or the drive means therefor
- F25B2700/21151—Temperatures of a compressor or the drive means therefor at the suction side of the compressor
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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
- F25B2700/00—Sensing or detecting of parameters; Sensors therefor
- F25B2700/21—Temperatures
- F25B2700/2115—Temperatures of a compressor or the drive means therefor
- F25B2700/21152—Temperatures of a compressor or the drive means therefor at the discharge side of the compressor
Definitions
- the refrigerant flowing between the heat source side heat exchanger and the use side heat exchanger is branched into a refrigerant circuit having a compressor, a heat source side heat exchanger, a use side heat exchanger, and a flow path switching mechanism, and sent to the compressor.
- a refrigeration cycle apparatus provided with an injection pipe, and an economizer heat exchanger that cools a refrigerant flowing between a heat source side heat exchanger and a use side heat exchanger by heat exchange with a refrigerant flowing through the injection pipe.
- a refrigeration cycle device including a refrigerant circuit having a compressor, a heat source side heat exchanger, a use side heat exchanger, and a flow path switching mechanism.
- a refrigerant flowing between a heat source side heat exchanger and a use side heat exchanger is branched into a refrigerant circuit.
- the flow path is switched to the cooling operation state in which the use-side heat exchanger circulates the refrigerant so as to function as the refrigerant evaporator.
- the switching mechanism is switched for operation (cooling operation)
- the refrigerant flowing between the heat source side heat exchanger and the use side heat exchanger can be cooled in the economizer heat exchanger.
- the heat source side heat exchanger is injected through the injection pipe.
- a part of the refrigerant flowing between the heat exchanger and the use-side heat exchanger is sent to the compressor, and the flow rate of the refrigerant discharged from the compressor can be increased by that amount.
- the flow rate of the refrigerant sent to the use-side heat exchanger increases, and the heat exchange capacity (radiation capacity of the use-side heat exchanger) obtained by radiating the refrigerant in the use-side heat exchanger can be increased.
- the heat radiation capability of the refrigerant in the heat source side heat exchanger may be reduced depending on the operating conditions, and accordingly, the cooling capability of the refrigerant in the economizer heat exchanger is insufficient, thereby causing It tends to be difficult to increase the evaporation capacity of the heat exchanger.
- the refrigerant flowing between the heat source side heat exchanger and the use side heat exchanger is cooled in the economizer heat exchanger according to the flow rate of the refrigerant sent to the compressor through the injection pipe.
- the enthalpy of the refrigerant sent to the heat source side heat exchanger decreases, whereby the amount of heat exchange required for evaporating the refrigerant in the heat source side heat exchanger tends to increase.
- the evaporating capacity of the use-side heat exchanger during operation in which the use-side heat exchanger functions as a refrigerant evaporator is desirable to make it possible to reduce the amount of heat exchange required for evaporating the refrigerant in the heat source side heat exchanger during the operation in which the use side heat exchanger functions as a refrigerant radiator. It is.
- the refrigeration cycle device has a main refrigerant circuit and a sub refrigerant circuit.
- the main refrigerant circuit includes a main compressor, a main heat source side heat exchanger, a main use side heat exchanger, an injection pipe, an economizer heat exchanger, and a main flow path switching mechanism.
- the main compressor is a compressor that compresses a main refrigerant.
- the main heat source side heat exchanger is a heat exchanger that functions as a radiator or an evaporator for the main refrigerant.
- the main use side heat exchanger is a heat exchanger that functions as an evaporator or a radiator of the main refrigerant.
- the injection pipe is a refrigerant pipe that branches the main refrigerant flowing between the main heat source side heat exchanger and the main use side heat exchanger and sends the branched refrigerant to the main compressor.
- the economizer heat exchanger is a heat exchanger that cools a main refrigerant flowing between a main heat source side heat exchanger and a main use side heat exchanger by heat exchange with a main refrigerant flowing through an injection pipe.
- the main flow path switching mechanism has a main cooling operation state in which the main refrigerant circulates so that the main use side heat exchanger functions as an evaporator of the main refrigerant, and the main use side heat exchanger functions as a radiator of the main refrigerant.
- the main refrigerant circuit has a sub-use-side heat exchanger that functions as a cooler or a heater of the main refrigerant cooled in the economizer heat exchanger.
- the sub refrigerant circuit includes a sub compressor, a sub heat source side heat exchanger, a sub use side heat exchanger, and a sub flow switching mechanism.
- the sub-compressor is a compressor that compresses a sub-refrigerant.
- the sub heat source side heat exchanger is a heat exchanger that functions as a radiator or an evaporator for the sub refrigerant.
- the sub-use-side heat exchanger functions as a sub-refrigerant evaporator and cools the main refrigerant cooled in the economizer heat exchanger, or functions as a sub-refrigerant radiator and is cooled in the economizer heat exchanger. This is a heat exchanger that heats the main refrigerant.
- the sub flow path switching mechanism is a sub-cooling operation state in which the sub-use side heat exchanger circulates the sub-refrigerant so as to function as a sub-refrigerant evaporator, and the sub-use side heat exchanger functions as a sub-refrigerant radiator. And a sub-heating operation state in which the sub-refrigerant is circulated as described above.
- the main refrigerant circuit in which the main refrigerant circulates provided with the same injection pipe and economizer heat exchanger as in the related art, but also a sub-refrigerant circuit in which a sub-refrigerant separate from the main refrigerant circuit is circulated.
- the sub-refrigerant circuit is provided for switching the main flow path switching mechanism to a cooling operation state in which the main refrigerant is circulated so that the main use side heat exchanger functions as an evaporator for the main refrigerant (cooling operation).
- the sub-use-side heat exchanger provided is provided in the main refrigerant circuit so as to function as a sub-refrigerant evaporator for cooling the main refrigerant cooled in the economizer heat exchanger. For this reason, here, the enthalpy of the main refrigerant sent to the main use side heat exchanger is further reduced, and the heat exchange capacity obtained by evaporation of the main refrigerant in the main use side heat exchanger (evaporation capacity of the use side heat exchanger) ) Can be increased.
- the sub-refrigerant circuit is provided.
- the sub-use-side heat exchanger is provided in the main refrigerant circuit so as to function as a sub-refrigerant radiator and function as a sub-refrigerant radiator for heating the main refrigerant cooled in the economizer heat exchanger. Therefore, here, the enthalpy of the main refrigerant sent to the main heat source side heat exchanger increases, and the amount of heat exchange required for evaporating the main refrigerant in the main heat source side heat exchanger can be reduced.
- the operation of the usage-side heat exchanger as a refrigerant evaporator during the operation of the usage-side heat exchanger It is possible to reduce the amount of heat exchange required for evaporating the refrigerant in the heat source side heat exchanger during operation in which the use side heat exchanger functions as a refrigerant radiator. it can.
- a refrigeration cycle apparatus is the refrigeration cycle apparatus according to the first aspect, wherein the main compressor includes a low-stage compression element for compressing the main refrigerant, and a main refrigerant discharged from the low-stage compression element. And a high-stage compression element for compressing.
- the main refrigerant circuit has an intermediate heat exchanger.
- the intermediate heat exchanger functions as a cooler for the main refrigerant flowing between the low-stage compression element and the high-stage compression element when the main flow switching mechanism is in the main cooling operation state.
- the intermediate heat exchanger functions as an evaporator for the main refrigerant heated in the sub-use-side heat exchanger when the main flow switching mechanism is in the main heating operation state.
- the intermediate pressure of the intermediate pressure flowing between the low-stage compression element and the high-stage compression element in the intermediate heat exchanger is changed. Since the refrigerant can be cooled, the temperature of the high-pressure main refrigerant discharged from the main compressor can be kept low. Moreover, here, as described above, when the main flow path switching mechanism is in the main heating operation state, the main refrigerant heated in the sub-use side heat exchanger can be evaporated in the intermediate heat exchanger. Therefore, the evaporation capacity can be increased as compared with the case where the main refrigerant heated in the sub-use-side heat exchanger is evaporated only by the main heat source-side heat exchanger.
- a refrigeration cycle apparatus is the refrigeration cycle apparatus according to the first aspect, wherein the main compressor includes a compression element having an intermediate injection port for introducing a main refrigerant from the outside during the compression stroke. .
- the injection pipe is connected to the intermediate injection port.
- the main refrigerant flowing through the injection pipe can be sent to an intermediate portion (intermediate injection port) of the compression stroke of the main compressor, which is a single-stage compressor, so that the main compressor is compressed to the intermediate pressure in the refrigeration cycle.
- the temperature of the main refrigerant can be reduced.
- a refrigeration cycle apparatus is the refrigeration cycle apparatus according to the first or second aspect, wherein the main compressor discharges the low-stage compression element for compressing the main refrigerant and the low-stage compression element. And a high-stage compression element for compressing the main refrigerant.
- the injection pipe is connected to the suction side of the high-stage compression element.
- the main refrigerant flowing through the injection pipe can be sent to an intermediate portion (between the low-stage compression element and the high-stage compression element) of the compression process of the main compressor which is a multi-stage compressor.
- the temperature of the main refrigerant compressed to the intermediate pressure in the refrigeration cycle in the machine can be reduced.
- a refrigeration cycle apparatus is the refrigeration cycle apparatus according to any one of the first to fourth aspects, wherein the main refrigerant circuit has a main expansion circuit between the economizer heat exchanger and the sub-use side heat exchanger. Has a mechanism.
- the main refrigerant before being depressurized by the main expansion mechanism can flow through the economizer heat exchanger, so that the main refrigerant in the economizer heat exchanger can be used. Cooling capacity can be increased.
- a refrigeration cycle apparatus is the refrigeration cycle apparatus according to the fifth aspect, further including a control unit that controls components of a main refrigerant circuit and a sub-refrigerant circuit.
- the control unit controls components of the main refrigerant circuit and the sub refrigerant circuit so that the main refrigerant circuit and the sub refrigerant circuit are linked.
- the sub-refrigerant circuit When the sub-refrigerant circuit is controlled independently of the main refrigerant circuit, when performing the cooling operation, the cooling heat amount of the main refrigerant in the economizer heat exchanger and the cooling heat amount of the main refrigerant in the sub-use-side heat exchanger The balance may be lost. Further, when performing the heating operation, the balance between the flow rate of the main refrigerant flowing through the injection pipe and the heating heat of the main refrigerant in the sub-use-side heat exchanger may be lost.
- the economizer heat exchange is performed.
- the balance between the cooling heat of the main refrigerant in the heat exchanger and the cooling heat of the main refrigerant in the sub-use-side heat exchanger is appropriate, and when performing the heating operation, the flow rate of the main refrigerant flowing through the injection pipe and the sub-use-side heat.
- a refrigeration cycle apparatus is the refrigeration cycle apparatus according to the sixth aspect, wherein the injection pipe has an injection expansion mechanism.
- the control unit controls the components of the injection expansion mechanism and the sub refrigerant circuit based on the coefficient of performance of the main refrigerant circuit.
- the components of the injection expansion mechanism and the sub refrigerant circuit are controlled based on the coefficient of performance of the main refrigerant circuit. Therefore, here, when performing the cooling operation, the cooling heat amount of the main refrigerant in the economizer heat exchanger and the cooling heat amount of the main refrigerant in the sub-use-side heat exchanger are balanced based on the coefficient of performance of the main refrigerant circuit.
- the flow rate of the main refrigerant flowing through the injection pipe and the heating heat amount of the main refrigerant in the sub-use-side heat exchanger can be balanced based on the coefficient of performance of the main refrigerant circuit. it can.
- the refrigeration cycle apparatus is the refrigeration cycle apparatus according to the seventh aspect, wherein the control unit sets the main flow path switching mechanism in the main cooling operation state and sets the sub flow path switching mechanism in the sub cooling operation state.
- the opening degree of the injection expansion mechanism is controlled such that the temperature of the main refrigerant at the inlet of the main expansion mechanism becomes the first main refrigerant target temperature
- the sub refrigerant is set based on the coefficient of performance of the main refrigerant circuit. Controls the components of the circuit.
- the injection expansion mechanism when controlling the components of the injection expansion mechanism and the sub-refrigeration circuit based on the coefficient of performance of the main refrigerant circuit when performing the cooling operation, the injection expansion mechanism based on the temperature of the main refrigerant at the inlet of the main expansion mechanism is controlled.
- the control it is possible to balance the cooling heat amount of the main refrigerant in the sub-use-side heat exchanger while securing the cooling heat amount of the main refrigerant in the economizer heat exchanger.
- a refrigeration cycle apparatus is the refrigeration cycle apparatus according to the seventh aspect, wherein the control unit sets the main flow path switching mechanism in the main cooling operation state and sets the sub flow path switching mechanism in the sub cooling operation state.
- the opening degree of the injection expansion mechanism is controlled so that the superheat degree of the main refrigerant flowing through the injection pipe at the outlet of the economizer heat exchanger becomes the first main refrigerant target superheat degree
- the main refrigerant circuit The components of the sub refrigerant circuit are controlled based on the coefficient of performance.
- the degree of superheat of the main refrigerant flowing through the injection pipe at the outlet of the economizer heat exchanger is controlled.
- a refrigeration cycle apparatus is the refrigeration cycle apparatus according to the eighth or ninth aspect, wherein the control unit is configured to control the temperature of the main refrigerant at the inlet of the main expansion mechanism, the coefficient of performance of the main refrigerant circuit,
- a first sub-refrigerant target temperature which is a target value of the temperature of the sub-refrigerant at the outlet of the sub-use-side heat exchanger, is set according to the correlation with the temperature of the sub-refrigerant at the outlet of the heat exchanger.
- the components of the sub refrigerant circuit are controlled so that the temperature of the sub refrigerant at the outlet of the exchanger becomes the first sub refrigerant target temperature.
- the cooling operation in controlling the components of the sub-refrigerant circuit based on the coefficient of performance of the main refrigerant circuit, the temperature of the sub-refrigerant at the outlet of the sub-use-side heat exchanger is changed to the inlet of the main expansion mechanism.
- the cooling heat amount of the main refrigerant in the sub-use heat exchanger is balanced. Can be done.
- a refrigeration cycle apparatus is the refrigeration cycle apparatus according to any one of the seventh to tenth aspects, wherein the control unit sets the main flow path switching mechanism to the main heating operation state, and switches the sub flow path.
- the control unit sets the main flow path switching mechanism to the main heating operation state, and switches the sub flow path.
- the performance of the main refrigerant circuit is controlled in a state where the opening degree of the injection expansion mechanism is controlled so that the temperature of the main refrigerant at the inlet of the main expansion mechanism becomes the second main refrigerant target temperature.
- the components of the sub refrigerant circuit are controlled based on the coefficient.
- the injection expansion mechanism when performing the heating operation, in controlling the components of the injection expansion mechanism and the sub-refrigerant circuit based on the coefficient of performance of the main refrigerant circuit, the injection expansion mechanism based on the temperature of the main refrigerant at the inlet of the main expansion mechanism is controlled. By the control, it is possible to balance the heating heat of the main refrigerant in the sub-use-side heat exchanger while securing the flow rate of the main refrigerant flowing through the injection pipe.
- a refrigeration cycle apparatus is the refrigeration cycle apparatus according to any one of the seventh to tenth aspects, wherein the control unit sets the main flow path switching mechanism to the main heating operation state, and switches the sub flow path.
- the degree of superheat of the main refrigerant flowing through the injection pipe at the outlet of the economizer heat exchanger is controlled.
- a refrigeration cycle apparatus is the refrigeration cycle apparatus according to the eleventh or twelfth aspect, wherein the control unit is configured to control the temperature of the main refrigerant at the inlet of the main expansion mechanism, the coefficient of performance of the main refrigerant circuit, A second sub-refrigerant target temperature, which is a target value of the sub-refrigerant temperature at the outlet of the sub-use-side heat exchanger, is set according to the correlation with the temperature of the sub-refrigerant at the outlet of the heat exchanger, and the sub-use-side heat is set.
- the components of the sub refrigerant circuit are controlled so that the temperature of the sub refrigerant at the outlet of the exchanger becomes the second sub refrigerant target temperature.
- the heating operation when the heating operation is performed, in controlling the components of the sub-refrigerant circuit based on the coefficient of performance of the main refrigerant circuit, the temperature of the sub-refrigerant at the outlet of the sub-use-side heat exchanger is changed to the inlet of the main expansion mechanism.
- the heating heat amount of the main refrigerant in the sub-use heat exchanger is balanced Can be done.
- a refrigeration cycle apparatus is the refrigeration cycle apparatus according to any of the first to thirteenth aspects, wherein the main refrigerant is carbon dioxide, and the sub-refrigerant is an HFC refrigerant or GFO having a GWP of 750 or less. It is a refrigerant or a mixed refrigerant of an HFC refrigerant and an HFO refrigerant.
- the environmental load such as global warming can be reduced.
- a refrigeration cycle apparatus is the refrigeration cycle apparatus according to any of the first to thirteenth aspects, wherein the main refrigerant is carbon dioxide, and the sub-refrigerant has a higher coefficient of performance than carbon dioxide. It is a refrigerant.
- the natural refrigerant having a higher coefficient of performance than carbon dioxide is used as the sub-refrigerant, the environmental load such as global warming can be reduced.
- FIG. 1 is a schematic configuration diagram of a refrigeration cycle device according to an embodiment of the present disclosure. It is a figure showing a flow of a refrigerant in a refrigeration cycle device at the time of cooling operation.
- FIG. 4 is a pressure-enthalpy diagram illustrating a refrigeration cycle during a cooling operation. It is a figure showing a flow of a refrigerant in a refrigeration cycle device at the time of heating operation.
- FIG. 3 is a pressure-enthalpy diagram illustrating a refrigeration cycle during a heating operation. It is a flowchart which shows the interlocking control of a main refrigerant circuit and a sub refrigerant circuit.
- FIG. 1 is a schematic configuration diagram of a refrigeration cycle device 1 according to an embodiment of the present disclosure.
- the refrigeration cycle device 1 includes a main refrigerant circuit 20 in which a main refrigerant circulates, and a sub-refrigerant circuit 80 in which a sub-refrigerant circulates, and is a device that performs indoor air conditioning (here, cooling and heating). .
- the main refrigerant circuit 20 mainly includes the main compressors 21 and 22, the main heat source side heat exchanger 25, the main use side heat exchangers 72a and 72b, the injection pipe 31, the economizer heat exchanger 32, and the sub use It has a side heat exchanger 85 and a first main channel switching mechanism 23.
- the main refrigerant circuit 20 includes an intermediate refrigerant pipe 61, a second main flow path switching mechanism 24, an intermediate heat exchanger 26, an intermediate heat exchange bypass pipe 63, a bridge circuit 40, and an upstream main expansion mechanism 27. And main use side expansion mechanisms 71a and 71b. Then, carbon dioxide is sealed in the main refrigerant circuit 20 as a main refrigerant.
- the main compressors 21 and 22 are devices that compress the main refrigerant.
- the first main compressor 21 is a compressor that drives a low-stage compression element 21a such as a rotary or scroll by a drive mechanism such as a motor or an engine.
- the second main compressor 22 is a compressor that drives a high-stage compression element 22a such as a rotary or scroll by a drive mechanism such as a motor or an engine.
- the main compressors 21 and 22 compress the main refrigerant in the low-stage first main compressor 21 and then discharge the main refrigerant, and discharge the main refrigerant discharged from the first main compressor 21 to the high-stage second main compressor 21.
- a multi-stage (here, two-stage) compressor configured to be compressed by the compressor 22 is configured.
- an intermediate refrigerant pipe 61 connects between the discharge side of the first main compressor 21 (low-stage compression element 21a) and the suction side of the second main compressor 22 (high-stage compression element 22a). ing.
- the first main flow path switching mechanism 23 is a mechanism for switching the direction of the flow of the main refrigerant in the main refrigerant circuit 20.
- the first main flow path switching mechanism 23 includes a main cooling operation state in which the main refrigerant is circulated so that the main use side heat exchangers 72a and 72b function as an evaporator of the main refrigerant, and a main use side heat exchanger 72a and 72b. Is a switching mechanism for switching between a main heating operation state in which the main refrigerant is circulated so as to function as a radiator of the main refrigerant.
- the first main flow path switching mechanism 23 is a four-way switching valve, and the suction side of the main compressors 21 and 22 (here, the suction side of the first main compressor 21), the main compressor 21 , 22 (here, the discharge side of the second main compressor 22), one end of the main heat source side heat exchanger 25, and the other end of the main use side heat exchangers 72a, 72b.
- the first main flow path switching mechanism 23 connects the discharge side of the second main compressor 22 to one end of the main heat source side heat exchanger 25, and Is connected to the other end of the main use side heat exchangers 72a, 72b (see the solid line of the first main flow path switching mechanism 23 in FIG. 1).
- the first main flow path switching mechanism 23 connects the discharge side of the second main compressor 22 to the other ends of the main use side heat exchangers 72a and 72b, and The suction side of the compressor 21 and one end of the main heat source side heat exchanger 25 are connected (see the broken line of the first main flow path switching mechanism 23 in FIG. 1).
- the first main flow path switching mechanism 23 is not limited to the four-way switching valve. For example, by combining a plurality of two-way valves or three-way valves, the same main refrigerant flow direction as described above can be used. It may be configured to have a switching function.
- the main heat source side heat exchanger 25 is a device for exchanging heat between the main refrigerant and the outdoor air, and here is a heat exchanger functioning as a radiator or an evaporator for the main refrigerant.
- One end of the main heat source side heat exchanger 25 is connected to the first main flow path switching mechanism 23, and the other end is connected to the bridge circuit 40.
- the main heat source side heat exchanger 25 functions as a radiator for the main refrigerant, and operates the first main flow path switching mechanism 23 with the main heating. When in the operating state, it functions as an evaporator for the main refrigerant.
- the bridge circuit 40 is provided between the main heat source side heat exchanger 25 and the main use side heat exchangers 72a and 72b.
- the main refrigerant circulating in the main refrigerant circuit 20 is supplied to the economizer heat exchanger 32 (the first economizer flow path) regardless of whether the first main flow path switching mechanism 23 is in the main cooling operation state or the main heating operation state. 32a), a circuit for rectifying the upstream main expansion mechanism 27 and the sub-use side heat exchanger 85 (second sub-flow path 85b) so that they flow in this order.
- the bridge circuit 40 has three check mechanisms 41, 42, 43 and a downstream main expansion mechanism 44.
- the inlet check mechanism 41 is a check valve that allows only the flow of the main refrigerant from the main heat source side heat exchanger 25 to the economizer heat exchanger 32 and the upstream side main expansion mechanism 27.
- the inlet check mechanism 42 is a check valve that allows only the flow of the main refrigerant from the main use side heat exchangers 72 a and 72 b to the economizer heat exchanger 32 and the upstream main expansion mechanism 27.
- the outlet check mechanism 43 is a check valve that allows only the flow of the main refrigerant from the sub use side heat exchanger 85 to the main use side heat exchangers 72a and 72b.
- the downstream main expansion mechanism 44 is a device for reducing the pressure of the main refrigerant.
- the downstream main expansion mechanism 44 is, for example, an electric expansion valve.
- the injection pipe 31 is a refrigerant pipe through which the main refrigerant flows.
- the main refrigerant flowing between the main heat source side heat exchanger 25 and the main use side heat exchangers 72a and 72b is branched to form a main compressor 21, 22 is a refrigerant pipe to be sent to 22.
- the injection pipe 31 branches the main refrigerant flowing between the inlet non-return mechanisms 41 and 42 of the bridge circuit 40 and the upstream main expansion mechanism 27 and sends it to the suction side of the second main compressor 22.
- It is a refrigerant pipe and has a first injection pipe 31a and a second injection pipe 31b.
- One end of the first injection pipe 31a is connected between the inlet check mechanisms 41, 42 of the bridge circuit 40 and the economizer heat exchanger 32 (one end of the first economizer flow path 32a), and the other end is connected to the economizer heat. It is connected to the exchanger 32 (one end of the second economizer flow path 32b).
- One end of the second injection pipe 31b is connected to the economizer heat exchanger 32 (the other end of the second economizer flow path 32b), and the other end is connected to the outlet of the intermediate heat exchanger 26 and the suction of the second main compressor 22. Connected between the side.
- the injection pipe 31 has an injection expansion mechanism 33.
- the injection expansion mechanism 33 is provided in the first injection pipe 31a.
- the injection expansion mechanism 33 is a device that decompresses the main refrigerant, and here is an expansion mechanism that depressurizes the main refrigerant flowing through the injection pipe 31.
- the injection expansion mechanism 33 is, for example, an electric expansion valve.
- the economizer heat exchanger 32 is a device for exchanging heat between main refrigerants.
- the main refrigerant flowing between the main heat source side heat exchanger 25 and the main use side heat exchangers 72a and 72b is passed through the injection pipe 31.
- This is a heat exchanger that cools by heat exchange with the flowing main refrigerant.
- the economizer heat exchanger 32 exchanges the main refrigerant flowing between the inlet check mechanisms 41 and 42 of the bridge circuit 40 and the upstream main expansion mechanism 27 with the main refrigerant flowing through the injection pipe 31. It is a heat exchanger for cooling.
- the economizer heat exchanger 32 includes a first economizer flow path 32 a through which main refrigerant flows between the inlet check mechanisms 41 and 42 of the bridge circuit 40 and the upstream main expansion mechanism 27, and a main refrigerant flowing through the injection pipe 31. And a second economizer flow path 32b for flowing.
- One end (inlet) of the first economizer flow path 32 a is connected to the inlet check mechanisms 41 and 42 of the bridge circuit 40, and the other end (outlet) is connected to the inlet of the upstream main expansion mechanism 27.
- One end (inlet) of the second economizer flow path 32b is connected to the other end of the first injection pipe 31a, and the other end (outlet) is connected to one end of the second injection pipe 31b.
- the upstream main expansion mechanism 27 is a device for decompressing the main refrigerant, and here, depressurizes the main refrigerant flowing between the economizer heat exchanger 32 and the sub-use side heat exchanger 85 (second sub flow path 85b). Expansion mechanism (main expansion mechanism). Specifically, the upstream-side main expansion mechanism 27 is provided between the inlet check mechanisms 41 and 42 of the bridge circuit 40 and the sub-use-side heat exchanger 85 (the second sub-flow path 85b). The upstream side main expansion mechanism 27 is, for example, an electric expansion valve. Note that the upstream main expansion mechanism 27 may be an expander that generates power by reducing the pressure of the main refrigerant.
- the sub-use-side heat exchanger 85 is a device that exchanges heat between the main refrigerant and the sub-refrigerant.
- the sub-use-side heat exchanger 85 is a heat exchanger that functions as a cooler or a heater of the main refrigerant cooled in the economizer heat exchanger 31. is there. That is, when the first main flow path switching mechanism 23 is in the main cooling operation state, the sub-use side heat exchanger 85 functions as a cooler for the main refrigerant cooled in the economizer heat exchanger 31, When the main flow path switching mechanism 23 is in the main heating operation state, it functions as a heater for the main refrigerant cooled in the economizer heat exchanger 31. Specifically, the sub-use-side heat exchanger 85 cools or heats the main refrigerant flowing between the upstream main expansion mechanism 27 and the third check mechanism 43 and the downstream main expansion mechanism 44 of the bridge circuit 40. It is a heat exchanger.
- the main use side expansion mechanisms 71a and 71b are devices for reducing the pressure of the main refrigerant.
- the main use side expansion mechanisms 71a and 71b are connected to the sub use side heat exchanger 85 and the main use side heat exchangers 72a and 72b.
- the main refrigerant flowing between the first and second main flow switching mechanisms 23a and 72b and the upstream main expansion mechanism 27 are depressurized. This is an expansion mechanism for reducing the pressure of the main refrigerant.
- the main use side expansion mechanisms 71a and 71b are provided between the inlet check mechanism 42 and the outlet check mechanism 43 of the bridge circuit 40 and one end of the main use side heat exchangers 72a and 72b. .
- the main use side expansion mechanisms 71a and 71b are, for example, electric expansion valves.
- the main use side heat exchangers 72a and 72b are devices for exchanging heat between the main refrigerant and the indoor air, and here are heat exchangers that function as evaporators or radiators of the main refrigerant.
- One end of each of the main use side heat exchangers 72a and 72b is connected to the main use side expansion mechanisms 71a and 71b, and the other end is connected to the suction side of the first compressor 21.
- the intermediate heat exchanger 26 is a device for exchanging heat between the main refrigerant and the outdoor air.
- the intermediate heat exchanger 26 when the first main flow path switching mechanism 23 is in the main cooling operation state, the intermediate heat exchanger 26 is connected to the first main compressor 21.
- the heat exchanger functions as a cooler for the main refrigerant flowing between the second main compressor 22.
- the intermediate heat exchanger 26 when the first main flow path switching mechanism 23 is in the main heating operation state, the intermediate heat exchanger 26 is configured to supply the main refrigerant heated in the sub use side heat exchanger 85 (the second sub flow path 85b). It is a heat exchanger that functions as an evaporator.
- the intermediate heat exchanger 26 is provided in the intermediate refrigerant pipe 61.
- the intermediate refrigerant pipe 61 has a first intermediate refrigerant pipe 61a, a second intermediate refrigerant pipe 61b, and a third intermediate refrigerant pipe 61c.
- One end of the first intermediate refrigerant pipe 61a is connected to the discharge side of the first main compressor 21 (low-stage compression element 21a), and the other end is connected to the second main flow path switching mechanism 24.
- the second intermediate refrigerant pipe 61 b has one end connected to the second main flow path switching mechanism 24 and the other end connected to one end of the intermediate heat exchanger 26.
- One end of the third intermediate refrigerant pipe 61c is connected to the other end of the intermediate heat exchanger 26, and the other end is connected to the suction side of the second main compressor 22 (high-stage compression element 22a).
- the other end of the second intermediate injection pipe 31b is connected to the third intermediate refrigerant pipe 61c.
- the intermediate heat exchange bypass pipe 63 transfers the main refrigerant discharged from the first main compressor 21 (lower stage compression element 21a) to the intermediate state.
- This is a refrigerant pipe that bypasses the heat exchanger 26 and sends it to the second main compressor 22 (high-stage compression element 22a).
- One end of the intermediate heat exchange bypass pipe 63 is connected to the second main flow path switching mechanism 24, and the other end is suction of the third intermediate refrigerant pipe 61 c and the second main compressor 22 (the high-stage side compression element 22 a). Connected to the part between the sides.
- the second main flow path switching mechanism 24 is a mechanism for switching the direction of the flow of the main refrigerant in the main refrigerant circuit 20.
- the second main flow path switching mechanism 24 includes an intermediate heat exchange / radiation state in which the main refrigerant discharged from the first main compressor 21 is passed through the intermediate heat exchanger 26 and then sent to the second main compressor 22.
- the second main flow path switching mechanism 24 is a four-way switching valve, and includes a discharge side of the first main compressor 21, one end of the second intermediate refrigerant pipe 61 b, and an intermediate heat exchange bypass pipe 63.
- the second main flow path switching mechanism 24 connects the discharge side of the first main compressor 21 and the suction side of the second main compressor 22 through the intermediate heat exchanger 26 in the intermediate heat exchange / radiation state. (See the solid line of the second main flow path switching mechanism 24 in FIG. 1). In the intermediate heat exchange bypass state, the discharge side of the first main compressor 21 and the suction side of the second main compressor 22 are connected through the intermediate heat exchange bypass pipe 64 (the second main flow path switching mechanism in FIG. 1). 24 dashed line).
- the second main flow path switching mechanism 24 is not limited to the four-way switching valve, and for example, by combining a plurality of two-way valves or three-way valves, or the like, changes the flow direction of the main refrigerant as described above. It may be configured to have a switching function.
- the first main compressor After the main refrigerant discharged from 21 is cooled in the intermediate heat exchanger 26, it can be caused to flow so as to be sucked into the second main compressor 22.
- the first main compressor when the first main flow path switching mechanism 23 is in the main heating operation state and the second main flow path switching mechanism 24 is in the intermediate heat exchange bypass state, the first main compressor The main refrigerant discharged from 21 can be caused to flow so as to be sucked into the second main compressor 22 by bypassing the intermediate heat exchanger 26 through the intermediate heat exchange bypass pipe 63.
- the sub refrigerant circuit 80 mainly includes a sub compressor 81, a sub heat source side heat exchanger 83, a sub use side heat exchanger 85, and a sub flow path switching mechanism 82.
- the sub refrigerant circuit 80 has a sub expansion mechanism 84.
- an HFC refrigerant (R32 or the like) having a GWP (global warming potential) of 750 or less, an HFO refrigerant (R1234yf or R1234ze or the like), or a mixed refrigerant of the HFC refrigerant and the HFO refrigerant (R452B etc.) are enclosed.
- the sub-refrigerant is not limited to these, and may be a natural refrigerant (propane, ammonia, or the like) having a higher coefficient of performance than carbon dioxide.
- the sub compressor 81 is a device that compresses the sub refrigerant.
- the sub-compressor 81 is a compressor that drives a compression element 81a such as a rotary or scroll by a drive mechanism such as a motor or an engine.
- the sub flow path switching mechanism 82 is a mechanism for switching the direction of the flow of the sub refrigerant in the sub refrigerant circuit 80.
- the sub passage switching mechanism 82 includes a sub-cooling operation state in which the sub-use side heat exchanger 85 circulates the sub-refrigerant so as to function as an evaporator for the sub-refrigerant.
- the sub flow path switching mechanism 82 is a four-way switching valve, and includes a suction side of the sub compressor 81, a discharge side of the sub compressor 81, one end of the sub heat source side heat exchanger 83, and It is connected to the other end of the side heat exchanger 85 (first sub flow path 85a).
- the sub flow path switching mechanism 82 connects the discharge side of the sub compressor 81 to one end of the sub heat source side heat exchanger 83, and connects the sub compressor 81 to the suction side.
- the other end of the side heat exchanger 85 (first sub flow path 85a) is connected (see the solid line of the sub flow path switching mechanism 82 in FIG. 1).
- the sub flow path switching mechanism 82 connects the discharge side of the sub compressor 81 to the other end of the sub use side heat exchanger 85 (first sub flow path 85a), and The suction side of the compressor 81 and one end of the sub heat source side heat exchanger 83 are connected (see the broken line of the sub flow path switching mechanism 82 in FIG. 1).
- the sub-channel switching mechanism 82 is not limited to a four-way switching valve, and is capable of switching the flow direction of the sub-refrigerant as described above, for example, by combining a plurality of two-way or three-way valves. May be provided.
- the sub heat source side heat exchanger 83 is a device for exchanging heat between the sub refrigerant and the outdoor air, and here is a heat exchanger that functions as a radiator or an evaporator for the sub refrigerant.
- One end of the sub heat source side heat exchanger 83 is connected to the sub flow path switching mechanism 82, and the other end is connected to the sub expansion mechanism 84.
- the sub-heat-source-side heat exchanger 83 functions as a radiator for the sub-refrigerant, and sets the sub-flow path switching mechanism 82 to the sub-heating operation state. , It functions as an evaporator for the sub-refrigerant.
- the sub-expansion mechanism 84 is a device that decompresses the sub-refrigerant.
- the sub-expansion mechanism 84 is an expansion mechanism that decompresses the sub-refrigerant flowing between the sub-heat-source-side heat exchanger 83 and the sub-use-side heat exchanger 85.
- the sub expansion mechanism 84 is provided between the other end of the sub heat source side heat exchanger 83 and the sub use side heat exchanger 85 (one end of the first sub flow path 85a).
- the sub-expansion mechanism 84 is, for example, an electric expansion valve.
- the sub-use-side heat exchanger 85 is a device that exchanges heat between the main refrigerant and the sub-refrigerant.
- the sub-use-side heat exchanger 85 functions as an evaporator for the sub-refrigerant and is cooled in the economizer heat exchanger 32.
- the heat exchanger cools the main refrigerant or functions as a radiator of the sub-refrigerant and heats the main refrigerant cooled in the economizer heat exchanger 32.
- the sub-use-side heat exchanger 85 converts the main refrigerant flowing between the upstream main expansion mechanism 27 and the third check mechanism 43 and the first downstream main expansion mechanism 44 of the bridge circuit 40 into a sub-refrigerant.
- the heat exchanger is cooled or heated by the refrigerant flowing through the circuit 80.
- the sub-use-side heat exchanger 85 includes a first sub-flow path 85 a through which a sub-refrigerant flowing between the sub-expansion mechanism 84 and the sub-flow path switching mechanism 82 flows, and a third reverse flow path of the gas-liquid separator 51 and the bridge circuit 40.
- a second sub flow path 85b through which the main refrigerant flows between the stop mechanism 43 and the first downstream main expansion mechanism 44.
- One end of the first sub flow path 85 a is connected to the sub expansion mechanism 84, and the other end is connected to the sub flow path switching mechanism 82.
- One end (inlet) of the second sub flow path 85b is connected to the upstream main expansion mechanism 27, and the other end (outlet) is connected to the third check mechanism 43 and the first downstream main expansion mechanism 44 of the bridge circuit 40. It is connected to the.
- the components of the main refrigerant circuit 20 and the sub-refrigerant circuit 80 are provided in the heat source unit 2, the plurality of use units 7a and 7b, and the sub-unit 8.
- the use units 7a and 7b are provided corresponding to the main use side heat exchangers 72a and 72b, respectively.
- the heat source unit 2 is arranged outdoors.
- the heat source unit 2 is provided with the main refrigerant circuit 20 excluding the sub use side heat exchanger 85, the main use side expansion mechanisms 71a and 71b, and the main use side heat exchangers 72a and 72b.
- the heat source unit 2 is provided with a heat source side fan 28 for sending outdoor air to the main heat source side heat exchanger 25 and the intermediate heat exchanger 26.
- the heat source side fan 28 is a fan that drives a blowing element such as a propeller fan by a driving mechanism such as a motor.
- the heat source unit 2 is provided with various sensors. Specifically, a pressure sensor 91 and a temperature sensor 92 for detecting the pressure and temperature of the main refrigerant on the suction side of the first main compressor 21 are provided. A pressure sensor 93 that detects the pressure of the main refrigerant on the discharge side of the first main compressor 21 is provided. A pressure sensor 94 and a temperature sensor 95 for detecting the pressure and temperature of the main refrigerant on the discharge side of the second main compressor 21 are provided. A temperature sensor 96 for detecting the temperature of the main refrigerant at the other end of the main heat source side heat exchanger 25 is provided.
- a temperature sensor 34 for detecting the temperature of the main refrigerant at the other end of the economizer heat exchanger 32 (the other end of the first economizer flow path 32a) is provided.
- a temperature sensor 35 for detecting the temperature of the main refrigerant in the second injection pipe 31b is provided.
- a pressure sensor 97 and a temperature sensor 98 for detecting the pressure and temperature of the main refrigerant between the upstream main expansion mechanism 27 and the sub-use side heat exchanger 85 are provided.
- a temperature sensor 105 for detecting the temperature of the main refrigerant at the other end of the sub-use side heat exchanger 85 (the other end of the second sub flow path 85b) is provided.
- a temperature sensor 99 for detecting the temperature of the outdoor air (outside air temperature) is provided.
- the use units 7a and 7b are arranged indoors.
- the main use side expansion mechanisms 71a, 71b and the main use side heat exchangers 72a, 72b of the main refrigerant circuit 20 are provided in the use units 7a, 7b.
- the use units 7a and 7b are provided with use side fans 73a and 73b for sending room air to the main use side heat exchangers 72a and 72b.
- the usage-side fans 73a and 73b are fans that drive a blowing element such as a centrifugal fan or a multi-blade fan by a drive mechanism such as a motor.
- various sensors are provided in the use units 7a and 7b. Specifically, temperature sensors 74a, 74b for detecting the temperature of the main refrigerant at one end of the main use side heat exchangers 72a, 72b, and the temperature of the main refrigerant at the other end of the main use side heat exchangers 72a, 72b Temperature sensors 75a and 75b for detecting
- the subunit 8 is arranged outside the room.
- the sub-refrigerant circuit 80 and a part of a refrigerant pipe constituting the main refrigerant circuit 20 are provided in the sub-unit 8. I have.
- the sub unit 8 is provided with a sub fan 86 for sending outdoor air to the sub heat source side heat exchanger 83.
- the sub-side fan 86 is a fan that drives a blowing element such as a propeller fan by a driving mechanism such as a motor.
- the sub-unit 8 is provided adjacent to the heat source unit 2, and the sub-unit 8 and the heat source unit 2 are substantially integrated.
- the subunit 8 may be provided separately from the heat source unit 2, or all the components of the subunit 8 may be provided in the heat source unit 2 and the subunit 8 may be omitted.
- the subunit 8 is provided with various sensors. Specifically, a pressure sensor 101 and a temperature sensor 102 for detecting the pressure and temperature of the sub refrigerant on the suction side of the sub compressor 81 are provided. A pressure sensor 103 and a temperature sensor 104 for detecting the pressure and temperature of the sub-refrigerant on the discharge side of the sub-compressor 81 are provided. A temperature sensor 106 for detecting the temperature of the outdoor air (outside air temperature) is provided. A temperature sensor 107 for detecting the temperature of the sub-refrigerant at one end of the sub-use-side heat exchanger 85 (one end of the first sub-flow path 85a) is provided.
- the heat source unit 2 and the use units 7a and 7b are connected by main refrigerant communication pipes 11 and 12 that constitute a part of the main refrigerant circuit 20.
- the first main refrigerant communication pipe 11 is a part of a pipe that connects the inlet check mechanism 42 and the outlet check mechanism 43 of the bridge circuit 40 with the main use-side expansion mechanisms 71a and 71b.
- the second main refrigerant communication pipe 12 is a part of a pipe connecting between the other ends of the main use side heat exchangers 72a and 72b and the first main flow path switching mechanism 23.
- the control unit 9 controls the components of the heat source unit 2 including the components of the main refrigerant circuit 20 and the sub-refrigerant circuit 80, the units 7a and 7b, and the sub-unit 8.
- the control unit 9 is configured such that control boards and the like provided in the heat source unit 2, the use units 7a and 7b, and the subunit 8 are connected by communication, and various sensors 34, 35, 74a, 74b, 75a, and 75b , 91 to 99, 101 to 107, and the like.
- the control unit 9 is illustrated at a position apart from the heat source unit 2, the use units 7a and 7b, the subunit 8, and the like.
- control unit 9 controls the components 21 to 24 of the refrigeration cycle apparatus 1 based on the detection signals of the various sensors 34, 35, 74a, 74b, 75a, 75b, 91 to 99, 101 to 107, and the like. Control of 27, 28, 33, 44, 71a, 71b, 73a, 73b, 81, 82, 84, 86, that is, operation control of the entire refrigeration cycle apparatus 1 is performed.
- FIG. 2 is a diagram illustrating the flow of the refrigerant in the refrigeration cycle apparatus 1 during the cooling operation.
- FIG. 3 is a pressure-enthalpy diagram illustrating a refrigeration cycle during the cooling operation.
- FIG. 4 is a diagram illustrating the flow of the refrigerant in the refrigeration cycle apparatus 1 during the heating operation.
- FIG. 5 is a pressure-enthalpy diagram illustrating a refrigeration cycle during a heating operation.
- FIG. 6 is a flowchart showing the interlocking control of the main refrigerant circuit 20 and the sub refrigerant circuit 80.
- FIG. 7 is a diagram showing changes in the coefficient of performance of the main refrigerant circuit 20 depending on the temperature Th1 of the main refrigerant at the inlet of the main expansion mechanism 27 and the temperature Ts1 of the sub-refrigerant at the outlet of the sub-use-side heat exchanger 85 during the cooling operation. is there.
- the refrigeration cycle apparatus 1 includes, as indoor air conditioning, a cooling operation (cooling operation) in which the main use side heat exchangers 72a and 72b function as an evaporator of the main refrigerant to cool the indoor air, and a main use side heat exchanger 72a. , 72b function as a radiator of the main refrigerant to heat the room air (heating operation). Also, here, a sub-refrigerant circuit cooling operation for cooling the main refrigerant using the sub-refrigerant circuit 80 during the cooling operation, and a sub-refrigerant circuit for heating the main refrigerant using the sub-refrigerant circuit 80 during the heating operation A heating operation can be performed. The operation of the cooling operation with the sub refrigerant circuit cooling operation and the heating operation with the sub refrigerant circuit heating operation are performed by the control unit 9.
- the first main flow path switching mechanism 23 is switched to the main cooling operation state shown by the solid line in FIG. 2, and the second main flow path switching mechanism 24 is switched to the intermediate heat exchange state shown by the solid line in FIG. The state can be switched to the heat radiation state. Further, since the first main channel switching mechanism 23 is switched to the main cooling operation state, the first downstream main expansion mechanism 44 is closed. In the cooling operation, the sub flow path switching mechanism 82 is switched to the sub cooling operation state shown by the solid line in FIG. 2 to perform the sub refrigerant circuit cooling operation.
- the low-pressure (LPh) main refrigerant in the refrigeration cycle (see point A in FIGS. 2 and 3) is sucked into the first main compressor 21, and the first main compressor 21 It is compressed to the intermediate pressure (MPh1) in the refrigeration cycle and discharged (see point B in FIGS. 2 and 3).
- the intermediate-pressure main refrigerant discharged from the first main compressor 21 is sent to the intermediate heat exchanger 26 through the second main flow path switching mechanism 24, and is sent to the intermediate heat exchanger 26 by the heat source side fan 28. It is cooled by performing heat exchange with outdoor air (see point C in FIGS. 2 and 3).
- the intermediate-pressure main refrigerant cooled in the intermediate heat exchanger 26 joins with the intermediate-pressure main refrigerant sent from the intermediate injection pipe 31 (second intermediate injection pipe 31b) to the suction side of the second main compressor 22. (See point D in FIGS. 2 and 3).
- the intermediate-pressure main refrigerant into which the main refrigerant has been injected from the intermediate injection pipe 31 is sucked into the second main compressor 22, and compressed and discharged to the high pressure (HPh) in the refrigeration cycle in the second main compressor 22. (See point E in FIGS. 2 and 3).
- the high-pressure main refrigerant discharged from the second main compressor 22 has a pressure exceeding the critical pressure of the main refrigerant.
- the high-pressure main refrigerant discharged from the second main compressor 22 is sent to the main heat source side heat exchanger 25, and exchanges heat with the outdoor air sent by the heat source side fan 28 in the main heat source side heat exchanger 25. And cooled (see point F in FIGS. 2 and 3).
- a part of the high-pressure main refrigerant cooled in the main heat source side heat exchanger 25 partially passes through the intermediate injection pipe 31 according to the opening degree of the intermediate injection expansion mechanism 33.
- the remainder is sent to the economizer heat exchanger 32 (first economizer flow path 32a).
- the high-pressure main refrigerant branched into the intermediate injection pipe 31 is reduced in pressure to the intermediate pressure (MPh1) in the intermediate injection expansion mechanism 33 to be in a gas-liquid two-phase state (see point K in FIGS. 2 and 3), and the economizer heat is generated. It is sent to the exchanger 32 (second economizer flow path 32b).
- the high-pressure main refrigerant flowing through the first economizer flow path 32a is cooled by performing heat exchange with the intermediate-pressure two-phase main refrigerant flowing through the second economizer flow path 32b ( (See point G in FIGS. 2 and 3).
- the main refrigerant in the gas-liquid two-phase state at the intermediate pressure flowing through the second economizer flow path 32b is heated by heat exchange with the high-pressure main refrigerant flowing through the first economizer flow path 32a (see FIGS. 2 and 3).
- Point L merges with the intermediate-pressure main refrigerant cooled in the intermediate heat exchanger 26, and is sent to the suction side of the second main compressor 22.
- the high-pressure main refrigerant cooled in the economizer heat exchanger 32 is sent to the upstream main expansion mechanism 27, where the main refrigerant is reduced in pressure to the intermediate pressure (MPh2) in the refrigeration cycle, and is gas-liquid two-phase. State (see point H in FIGS. 2 and 3).
- the intermediate-pressure main refrigerant depressurized in the upstream-side main expansion mechanism 27 is sent to the sub-use-side heat exchanger 85 (the second sub-flow path 85b).
- the low-pressure (LPs) sub-refrigerant (see point R in FIGS. 2 and 3) in the refrigeration cycle is sucked into the sub-compressor 81, and (HPs) and discharged (see point S in FIGS. 2 and 3).
- the high-pressure sub-refrigerant discharged from the sub-compressor 81 is sent to the sub-heat-source-side heat exchanger 83 through the sub-flow-path switching mechanism 82, where the outdoor air is sent by the sub-side fan 86 in the sub-heat-source-side heat exchanger 83. It is cooled by exchanging heat with air (see point T in FIGS. 2 and 3).
- the high-pressure sub-refrigerant cooled in the sub-heat-source-side heat exchanger 83 is sent to the sub-expansion mechanism 84, where it is decompressed to a low pressure and enters a gas-liquid two-phase state (FIGS. 2 and 3). Point U).
- the intermediate-pressure main refrigerant flowing through the second sub-flow path 85b exchanges heat with the low-pressure gas-liquid two-phase sub-refrigerant flowing through the first sub-flow path 85a. It is cooled (see point I in FIGS. 2 and 3). Conversely, the low-pressure gas-liquid two-phase sub-refrigerant flowing through the first sub-flow path 85a exchanges heat with the intermediate-pressure main refrigerant flowing through the second sub-flow path 85b and is heated (see FIGS. 2 and 5). (Refer to the point R in FIG. 3), and is again sucked into the suction side of the sub-compressor 81 through the sub-channel switching mechanism 82.
- the intermediate-pressure main refrigerant cooled in the sub-use-side heat exchanger 85 is sent to the main use-side expansion mechanisms 71a and 71b through the outlet check mechanism 43 of the bridge circuit 40 and the first main refrigerant communication pipe 11, and In the use-side expansion mechanisms 71a and 71b, the pressure is reduced to a low pressure (LPh) to be in a gas-liquid two-phase state (see point J in FIGS. 2 and 3).
- LPh low pressure
- the low-pressure main refrigerant decompressed in the main use side expansion mechanisms 71a, 71b is sent to the main use side heat exchangers 72a, 72b, and sent by the use side fans 73a, 73b in the main use side heat exchangers 72a, 72b. It heats and evaporates by performing heat exchange with the room air to be produced (see point A in FIGS. 2 and 3). Conversely, the indoor air is cooled by performing heat exchange with the low-pressure two-phase main refrigerant flowing through the main use side heat exchangers 72a and 72b, thereby cooling the room.
- the low-pressure main refrigerant evaporated in the main use side heat exchangers 72a and 72b is sent to the suction side of the first main compressor 21 through the second main refrigerant communication pipe 12 and the first main flow path switching mechanism 23, and again. Is sucked into the first main compressor 21. In this way, the cooling operation with the sub-refrigerant circuit cooling operation is performed.
- the first main flow path switching mechanism 23 is switched to the main heating operation state shown by the broken line in FIG. 4, and the second main flow path switching mechanism 24 is switched to the intermediate heat exchange state shown by the broken line in FIG. The state is switched to the bypass state. Further, since the first main channel switching mechanism 23 is switched to the main heating operation state, the first downstream main expansion mechanism 44 is opened. Further, during the heating operation, the sub-flow path switching mechanism 82 is switched to the sub-heating operation state indicated by the broken line in FIG. 4 to perform the sub-refrigerant circuit heating operation.
- the low-pressure (LPh) main refrigerant in the refrigeration cycle (see point A in FIGS. 4 and 5) is sucked into the first main compressor 21, and It is compressed and discharged to the intermediate pressure (MPh1) in the refrigeration cycle (see point B in FIGS. 4 and 5).
- the intermediate-pressure main refrigerant discharged from the first main compressor 21 does not radiate heat in the intermediate heat exchanger 26 through the second main flow path switching mechanism 24 and the intermediate heat exchange bypass pipe 63, and the second main compressor 22 is sent to the suction side.
- the intermediate-pressure main refrigerant bypassing the intermediate heat exchanger 26 joins with the intermediate-pressure main refrigerant sent from the intermediate injection pipe 31 (second intermediate injection pipe 31b) to the suction side of the second main compressor 22. It is cooled (see point D in FIGS. 4 and 5).
- the intermediate-pressure main refrigerant into which the main refrigerant has been injected from the intermediate injection pipe 31 is sucked into the second main compressor 22, and compressed and discharged to the high pressure (HPh) in the refrigeration cycle in the second main compressor 22. (See point E in FIGS. 4 and 5).
- the high-pressure main refrigerant discharged from the second main compressor 22 has a pressure exceeding the critical pressure of the main refrigerant.
- the high-pressure main refrigerant discharged from the second main compressor 22 is sent to the main use side heat exchangers 72 a and 72 b through the first main flow path switching mechanism 23 and the second main refrigerant communication pipe 12, and In the heat exchangers 72a and 72b, heat is exchanged with room air sent by the use side fans 73a and 73b to radiate heat (see point J in FIGS. 4 and 5). Conversely, the indoor air is heated by exchanging heat with the high-pressure main refrigerant flowing through the main-use-side heat exchangers 72a and 72b, thereby heating the room.
- the high-pressure main refrigerant radiated in the main use side heat exchangers 72a and 72b passes through the main use side expansion mechanisms 71a and 71b, the first main refrigerant communication pipe 11, and the inlet check mechanism 42 of the bridge circuit 40, and then the A part is branched into the intermediate injection pipe 31 according to the opening degree of the intermediate injection expansion mechanism 33, and the remainder is sent to the economizer heat exchanger 32 (first economizer flow path 32a).
- the high-pressure main refrigerant branched into the intermediate injection pipe 31 is reduced in pressure to the intermediate pressure (MPh1) in the intermediate injection expansion mechanism 33 to be in a gas-liquid two-phase state (see point K in FIGS. 4 and 5), and the economizer heat is generated.
- the exchanger 32 (second economizer flow path 32b).
- the high-pressure main refrigerant flowing through the first economizer flow path 32a is cooled by performing heat exchange with the intermediate-pressure two-phase main refrigerant flowing through the second economizer flow path 32b ( (See point G in FIGS. 4 and 5).
- the main refrigerant in the gas-liquid two-phase state at the intermediate pressure flowing through the second economizer flow path 32b is heated by heat exchange with the high-pressure main refrigerant flowing through the first economizer flow path 32a (see FIGS. 4 and 5).
- Point L merges with the intermediate-pressure main refrigerant bypassing the intermediate heat exchanger 26, and is sent to the suction side of the second main compressor 22.
- the high-pressure main refrigerant cooled in the economizer heat exchanger 32 is sent to the upstream main expansion mechanism 27, where the main refrigerant is reduced in pressure to the intermediate pressure (MPh2) in the refrigeration cycle, and is gas-liquid two-phase. State (see point H in FIGS. 4 and 5).
- the intermediate-pressure main refrigerant depressurized in the upstream-side main expansion mechanism 27 is sent to the sub-use-side heat exchanger 85 (the second sub-flow path 85b).
- the low-pressure (LPs) sub-refrigerant (see point R in FIGS. 4 and 5) in the refrigeration cycle is sucked into the sub-compressor 81, and (HPs) and discharged (see point S in FIGS. 4 and 5).
- the high-pressure sub-refrigerant discharged from the sub-compressor 81 is sent to the sub-heat-source-side heat exchanger 83 through the sub-channel switching mechanism 82.
- the intermediate-pressure main refrigerant flowing through the second sub-flow path 85b exchanges heat with the high-pressure sub-refrigerant flowing through the first sub-flow path 85a and is heated (FIG. 4). And point I in FIG. 5).
- the high-pressure sub-refrigerant flowing through the first sub-flow path 85a is cooled by performing heat exchange with the intermediate-pressure main refrigerant flowing through the second sub-flow path 85b (see point U in FIGS. 4 and 5). .
- the high-pressure sub-refrigerant cooled in the sub-use-side heat exchanger 85 is sent to the sub-expansion mechanism 84, where it is decompressed to a low pressure and enters a gas-liquid two-phase state (FIGS. 4 and 5). Point T).
- the low-pressure sub-refrigerant that has been decompressed in the sub-expansion mechanism 84 is sent to the sub-heat-source-side heat exchanger 83, where the sub-heat-source-side heat exchanger 83 exchanges heat with outdoor air sent by the sub-side fan 86 to heat. Then, it is sucked into the suction side of the sub-compressor 81 again through the sub-channel switching mechanism 82 (see point R in FIGS. 4 and 5).
- the intermediate-pressure main refrigerant heated in the sub-use-side heat exchanger 85 is decompressed to a low pressure in the first downstream main expansion mechanism 44 of the bridge circuit 40 (see point F in FIGS. 4 and 5), and The refrigerant is sent to the main heat source side heat exchanger 25 functioning as a refrigerant evaporator.
- the low-pressure main refrigerant sent to the main heat source side heat exchanger 25 evaporates by performing heat exchange with outdoor air supplied by the heat source side fan 28 in the main heat source side heat exchanger 25. Then, the low-pressure main refrigerant evaporated in the main heat source side heat exchanger 25 is sent to the suction side of the first main compressor 21 through the first main flow path switching mechanism 23, and is again sent to the first main compressor 21. Inhaled. Thus, the heating operation with the sub refrigerant circuit heating operation is performed.
- the sub refrigerant circuit 80 when the sub refrigerant circuit 80 is controlled independently of the main refrigerant circuit 20, when performing the cooling operation, the cooling heat amount of the main refrigerant in the economizer heat exchanger 32 (see points F and G in FIG. 3). ) And the amount of cooling heat of the main refrigerant in the sub-use-side heat exchanger 85 (see points H and I in FIG. 3) may be lost. Further, when performing the heating operation, the balance between the flow rate of the main refrigerant flowing through the injection pipe 31 and the heating heat amount of the main refrigerant in the sub-use-side heat exchanger 85 (points H and I in FIG. 5) may be lost. is there.
- the components of the main refrigerant circuit 20 and the sub-refrigerant circuit 80 are controlled so that the main refrigerant circuit 20 and the sub-refrigerant circuit 80 are linked as described below. Accordingly, when performing the cooling operation, the balance between the cooling heat amount of the main refrigerant in the economizer heat exchanger 32 and the cooling heat amount of the main refrigerant in the sub-use-side heat exchanger 85 is appropriately set, and the heating operation is performed. Therefore, the balance between the flow rate of the main refrigerant flowing through the injection pipe 31 and the amount of heating heat of the main refrigerant in the sub-use-side heat exchanger 85 is appropriately set.
- step ST1 Interlocking control during cooling operation with sub refrigerant circuit cooling operation-
- the control unit 9 starts the cooling operation with the sub refrigerant circuit cooling operation in step ST11.
- the injection expansion mechanism 33 is set to a predetermined opening, and in the sub refrigerant circuit 80, the sub compressor 81 is set to a predetermined capacity, and the sub expansion mechanism 84 is set to a predetermined opening.
- step ST12 the control unit 9 controls the opening degree of the injection expansion mechanism 33 based on the superheat degree SHh1 of the main refrigerant flowing through the injection pipe 31 at the outlet of the economizer heat exchanger 32.
- the control unit 9 controls the opening degree of the injection expansion mechanism 33 so that the superheat degree SHh1 becomes the first main refrigerant target superheat degree SHh1t.
- the superheat degree SHh1 is obtained by converting the pressure (MPh1) of the main refrigerant detected by the pressure sensor 93 into a saturation temperature, and subtracting this saturation temperature from the temperature of the main refrigerant detected by the temperature sensor 35.
- the first main refrigerant target superheat degree SHh1t is determined by operating conditions of the main refrigerant circuit 20 (the outside air temperature Ta, the high pressure HPh of the main refrigerant, the low pressure LPh of the main refrigerant, the temperature Th2 of the main refrigerant in the main heat source side heat exchanger 25). And the like (one or more of the state quantities relating to the various main refrigerant circuits 20).
- the outside air temperature Ta is detected by the temperature sensor 99 or the temperature sensor 106
- the temperature Th1 is detected by the temperature sensor 96
- the high pressure HPh is detected by the pressure sensor 94
- the low pressure LPh is detected by the pressure sensor 91.
- step ST13 the control unit 9 sets the coefficient of performance COP of the main refrigerant circuit 20 in a state where the opening degree of the injection expansion mechanism 33 is controlled such that the superheat degree SHh1 becomes the first main refrigerant target superheat degree SHh1t. Based on this, the components of the sub-refrigerant circuit 20 are controlled.
- the coefficient of performance COP of the main refrigerant circuit 20 during the cooling operation is determined by the temperature Th1 of the main refrigerant at the inlet of the main expansion mechanism 27 (the outlet of the economizer heat exchanger 32) and the temperature of the sub-refrigerant at the outlet of the sub-use-side heat exchanger 85.
- Ts1 has a correlation as shown in FIG. This correlation indicates a balance between the cooling heat of the main refrigerant in the economizer heat exchanger 32 and the cooling heat of the main refrigerant in the sub-use-side heat exchanger 85. For example, when the temperature Th1 of the main refrigerant is 40 ° C. In this case, when the temperature Ts1 of the sub-refrigerant is 25 ° C., the coefficient of performance COP of the main refrigerant circuit 20 becomes maximum.
- the evaporating capacity Qe of the use-side heat exchangers 72a and 72b during the cooling operation increases as the amount of cooling heat of the main refrigerant in the sub-use-side heat exchanger 85 increases by the sub-refrigerant circuit cooling operation.
- increasing the cooling heat amount of the main refrigerant by the sub-refrigerant circuit cooling operation means increasing the power consumption Ws of the sub-refrigerant circuit 80 (mainly, the power consumption of the sub-compressor 81).
- the coefficient of performance COP of the main refrigerant circuit 20 is obtained by calculating the evaporation capacity Qe between the power consumption Wh of the main refrigerant circuit 20 (mainly the power consumption of the main compressors 21 and 22) and the power consumption Ws of the sub refrigerant circuit 80. It is expressed by the value divided by the total value, that is, Qe / (Wh + Ws).
- the control unit 9 has this correlation in the form of a data table or a function, and according to the correlation, determines the temperature of the sub-refrigerant Ts1 at the outlet of the sub-use-side heat exchanger 85.
- a first sub-refrigerant target temperature Ts1t that is a target value is set.
- the control unit 9 obtains the temperature of the sub-refrigerant at which the coefficient of performance COP of the main refrigerant circuit 20 becomes maximum from the temperature Th1 of the main refrigerant, and sets this temperature value to the first sub-refrigerant target temperature Ts1t.
- the control unit 9 controls the components of the sub-refrigerant circuit 20 so that the sub-refrigerant temperature Ts1 becomes the first sub-refrigerant target temperature Ts1t. Specifically, the control unit 9 controls the opening degree of the sub-expansion mechanism 84 and the operating capacity of the sub-compressor 81 such that the sub-refrigerant temperature Ts1 becomes the first sub-refrigerant target temperature Ts1t. Here, the control unit 9 controls the opening degree of the sub expansion mechanism 84 based on the superheat degree SHs1 of the sub refrigerant at the outlet of the sub use side heat exchanger 85 on the sub refrigerant circuit 80 side.
- the control unit 9 controls the opening of the sub-expansion mechanism 84 so that the superheat degree SHs1 becomes the target value SHs1t.
- the superheat degree SHs1 is obtained by converting the sub-refrigerant pressure (LPs) detected by the pressure sensor 101 into a saturation temperature, and subtracting this saturation temperature from the sub-refrigerant temperature Ts1 detected by the temperature sensor 102. .
- the control unit 9 controls the opening degree of the sub-expansion mechanism 84 based on the superheat degree SHs1 of the sub-refrigerant, and sets the sub-compressor 81 so that the sub-refrigerant temperature Ts1 becomes the first sub-refrigerant target temperature Ts1t. Control the operating capacity (operating frequency and rotational speed) of the
- the control unit 9 sets the components of the injection expansion mechanism 33 and the sub-refrigerant circuit 80 (the sub-compressor 81 and the sub-compressor 81) based on the coefficient of performance COP of the main refrigerant circuit 20.
- the sub-expansion mechanism 84 is controlled.
- the opening of the sub-expansion mechanism 84 is controlled so that the sub-refrigerant temperature Ts1 becomes the first sub-refrigerant target temperature Ts1t. The degree may be controlled.
- step ST1 Interlocking control during heating operation with sub refrigerant circuit heating operation-
- the control unit 9 starts the heating operation with the sub-refrigerant circuit heating operation in step ST12.
- the injection expansion mechanism 33 is set to a predetermined opening, and in the sub refrigerant circuit 80, the sub compressor 81 is set to a predetermined capacity, and the sub expansion mechanism 84 is set to a predetermined opening.
- step ST22 the control unit 9 controls the opening degree of the injection expansion mechanism 33 based on the superheat degree SHh1 of the main refrigerant flowing through the injection pipe 31 at the outlet of the economizer heat exchanger 32, as in the cooling operation. I do. However, in consideration of the heating operation, the control unit 9 determines here that the superheat degree SHh1 is different from the second main refrigerant target superheat degree SHh2t (the first main refrigerant target superheat degree SHh1t during the cooling operation). ), The opening of the injection expansion mechanism 33 is controlled.
- step ST23 the control unit 9 sets the coefficient of performance COP of the main refrigerant circuit 20 in a state where the opening degree of the injection expansion mechanism 33 is controlled such that the superheat degree SHh1 becomes the second main refrigerant target superheat degree SHh2t. Based on this, the components of the sub-refrigerant circuit 20 are controlled.
- the coefficient of performance COP of the main refrigerant circuit 20 during the heating operation is the same as that during the cooling operation (see FIG. 7), as in the case of the cooling operation (see FIG. 7).
- a temperature Ts2 of the sub-refrigerant at the outlet of the sub-use-side heat exchanger 85 since the temperature Th1 of the main refrigerant at the inlet of the main expansion mechanism 27 (the outlet of the economizer heat exchanger 32) is equivalent to the flow rate of the main refrigerant flowing through the injection pipe 31, this correlation is obtained by using the injection pipe 31. This can be said to indicate a balance relationship between the flow rate of the flowing main refrigerant and the amount of heating heat of the main refrigerant in the sub-use-side heat exchanger 85.
- the heat radiating capacity Qr of the use-side heat exchangers 72a and 72b during the heating operation increases as the heating amount of the main refrigerant in the sub-use-side heat exchanger 85 increases by the sub-refrigerant circuit heating operation.
- increasing the amount of heating heat of the main refrigerant by the sub refrigerant circuit heating operation means increasing the power consumption Ws of the sub refrigerant circuit 80 (mainly, the power consumption of the sub compressor 81).
- the coefficient of performance COP of the main refrigerant circuit 20 is obtained by calculating the heat dissipation capacity Qr between the power consumption Wh of the main refrigerant circuit 20 (mainly the power consumption of the main compressors 21 and 22) and the power consumption Ws of the sub refrigerant circuit 80. It is expressed by the value divided by the total value, that is, Qr / (Wh + Ws). For this reason, if the heating power of the main refrigerant by the sub-refrigerant circuit heating operation is increased with respect to the flow rate of the main refrigerant flowing through the injection pipe 31, the performance of the main refrigerant circuit 20 is reduced in a range where the power consumption Ws of the sub-refrigerant circuit 80 is small.
- the coefficient COP of the main refrigerant circuit 20 tends to decrease in a range where the power consumption Ws of the sub refrigerant circuit 80 is large. That is, the coefficient of performance COP of the main refrigerant circuit 20 changes according to the balance between the flow rate of the main refrigerant flowing through the injection pipe 31 and the amount of heating heat of the main refrigerant in the sub-use-side heat exchanger 85, and there is an optimum point.
- the control unit 9 has this correlation in the form of a data table or a function, and according to the correlation, determines the temperature of the sub-refrigerant Ts2 at the outlet of the sub-use-side heat exchanger 85.
- a second sub-refrigerant target temperature Ts2t which is a target value is set.
- the control unit 9 obtains the temperature of the sub-refrigerant at which the coefficient of performance COP of the main refrigerant circuit 20 becomes maximum from the temperature Th1 of the main refrigerant, and sets this temperature value to the second sub-refrigerant target temperature Ts2t.
- the control unit 9 controls the components of the sub-refrigerant circuit 20 so that the sub-refrigerant temperature Ts2 becomes the second sub-refrigerant target temperature Ts2t. Specifically, the control unit 9 controls the opening degree of the sub-expansion mechanism 84 and the operating capacity of the sub-compressor 81 so that the sub-refrigerant temperature Ts2 becomes the second sub-refrigerant target temperature Ts2t. Here, the control unit 9 controls the opening degree of the sub-expansion mechanism 84 based on the sub-cooling degree SCs1 of the sub-refrigerant at the outlet of the sub-use-side heat exchanger 85 on the sub-refrigerant circuit 80 side.
- the control unit 9 controls the opening degree of the sub-expansion mechanism 84 so that the subcooling degree SCs1 becomes the target value SCs1t.
- the subcooling degree SCs1 is obtained by converting the sub-refrigerant pressure (HPs) detected by the pressure sensor 103 into a saturation temperature and subtracting the sub-refrigerant temperature Ts2 detected by the temperature sensor 107 from the saturation temperature.
- the control unit 9 controls the opening degree of the sub-expansion mechanism 84 based on the sub-cooling degree SCs1 of the sub-refrigerant and sets the sub-compressor so that the sub-refrigerant temperature Ts2 becomes the second sub-refrigerant target temperature Ts2t.
- the operating capacity (operating frequency and rotation speed) of the control unit 81 is controlled.
- the control unit 9 controls the components of the injection expansion mechanism 33 and the sub refrigerant circuit 80 (the sub compressor 81 and the sub compressor 81) based on the coefficient of performance COP of the main refrigerant circuit 20.
- the sub-expansion mechanism 84 is controlled.
- the opening of the sub-expansion mechanism 84 is controlled so that the sub-refrigerant temperature Ts2 becomes the second sub-refrigerant target temperature Ts2t. The degree may be controlled.
- the operation is performed.
- the sub-use-side heat exchanger 85 provided in the sub-refrigerant circuit 80 is provided in the main refrigerant circuit 20 so as to function as a sub-refrigerant evaporator that cools the main refrigerant cooled in the economizer heat exchanger 32. I have. Therefore, here, the enthalpy of the main refrigerant sent to the main use side heat exchangers 72a, 72b further decreases (see points H and I in FIG.
- the heat exchange capacity obtained by evaporation (evaporation capacity of the use-side heat exchangers 72a and 72b) can be increased (see points J and A in FIG. 3).
- the sub-use-side heat exchanger 85 provided in the sub-refrigerant circuit 80 functions as a sub-refrigerant radiator and functions as a sub-refrigerant radiator that heats the main refrigerant cooled in the economizer heat exchanger 32.
- the enthalpy of the main refrigerant sent to the main heat source side heat exchanger 25 increases (see points H and I in FIG.
- the main heat source side heat exchanger 25 it is necessary for the main heat source side heat exchanger 25 to evaporate the main refrigerant.
- the amount of heat exchange can be reduced (see points F and A in FIG. 5).
- the heat exchange efficiency of the main heat source side heat exchanger 25 increases, and the low pressure (LPh) of the main refrigerant increases, so that the power consumption of the main compressors 21 and 22 can be reduced.
- the low pressure of the main refrigerant increases during the heating operation, frost formation in the main heat source side heat exchanger 25 is suppressed, so that the frequency of performing the defrost operation can be reduced.
- the evaporation capacity of the use side heat exchangers 72a and 72b can be increased.
- the amount of heat exchange required for evaporating the refrigerant in the heat-source-side heat exchanger 25 can be reduced.
- the evaporation capacity of the main use side heat exchangers 72a and 72b can be increased during the cooling operation using the sub refrigerant circuit 80, and the main heat source can be increased during the heating operation. Since the amount of heat exchange required for evaporating the refrigerant in the side heat exchanger 25 can be reduced, desired performance can be obtained even though carbon dioxide is used as the main refrigerant.
- the main refrigerant flowing through the injection pipe 31 is supplied to the middle part of the compression stroke of the main compressors 21 and 22 (between the low-stage compression element 21a and the high-stage compression element 22a). Therefore, the temperature of the main refrigerant compressed to the intermediate pressure (MPh1) in the refrigeration cycle in the main compressors 21 and 22 can be reduced.
- the first main compressor 21 lower-stage Since the intermediate-pressure main refrigerant flowing between the side compression element 21a
- the second main compressor 22 high-stage compression element 22a
- the temperature of the high-pressure main refrigerant discharged from the compressor 22 can be kept low (see point E in FIG. 3).
- the heating in the intermediate heat exchanger 26 and the sub-use side heat exchanger 85 is performed.
- the evaporated main refrigerant can be evaporated.
- the main refrigerant before being depressurized by the main expansion mechanism 27 can flow through the economizer heat exchanger 32 in both the cooling operation and the heating operation. Therefore, the cooling capacity of the main refrigerant in the economizer heat exchanger 32 can be increased.
- control unit 9 controls the components of the main refrigerant circuit 20 and the sub refrigerant circuit 80 so that the main refrigerant circuit 20 and the sub refrigerant circuit 80 work together. Accordingly, when performing the cooling operation, the balance between the cooling heat amount of the main refrigerant in the economizer heat exchanger 32 and the cooling heat amount of the main refrigerant in the sub-use-side heat exchanger 85 is appropriately set, and the heating operation is performed. Thus, the balance between the flow rate of the main refrigerant flowing through the injection pipe 31 and the heating heat of the main refrigerant in the sub-use-side heat exchanger 85 can be made appropriate.
- the cooling heat amount of the main refrigerant in the economizer heat exchanger 32 and the cooling of the main refrigerant in the sub-use side heat exchanger 85 are determined based on the coefficient of performance COP of the main refrigerant circuit 20.
- the amount of heat can be balanced, and when performing the heating operation, the flow rate of the main refrigerant flowing through the injection pipe 31 and the flow rate of the main refrigerant in the sub-use-side heat exchanger 85 are determined based on the coefficient of performance COP of the main refrigerant circuit 20.
- the amount of heat to be heated can be balanced.
- the economizer heat exchanger 32 when controlling the components of the injection expansion mechanism 33 and the sub-refrigerant circuit 80 based on the coefficient of performance COP of the main refrigerant circuit 20 during the cooling operation, the economizer heat exchanger 32 is used.
- the injection expansion mechanism 33 is controlled based on the degree of superheat SHh1 of the main refrigerant flowing through the injection pipe 31 at the outlet of.
- the sub-refrigerant circuit 80 when performing the cooling operation, in controlling the components of the sub-refrigerant circuit 80 based on the coefficient of performance COP of the main refrigerant circuit 20, at the outlet of the sub-use-side heat exchanger 85
- the sub-refrigerant circuit 80 is controlled such that the sub-refrigerant temperature Ts1 becomes the first sub-refrigerant target temperature Ts1t obtained based on the main refrigerant temperature Th1 at the inlet of the main expansion mechanism 27 and the coefficient of performance COP of the main refrigerant circuit 20. doing.
- the outlet of the sub-use-side heat exchanger 85 is controlled.
- the sub-refrigerant circuit 80 is controlled such that the sub-refrigerant temperature Ts2 becomes the second sub-refrigerant target temperature Ts2t obtained based on the main refrigerant temperature Th1 at the inlet of the main expansion mechanism 27 and the coefficient of performance COP of the main refrigerant circuit 20. doing.
- control unit 9 controls the opening degree of the injection expansion mechanism 33 based on the superheat degree SHh1 of the main refrigerant flowing through the injection pipe 31 at the outlet of the economizer heat exchanger 32.
- the present invention is not limited to this.
- the control unit 9 sets target values Th1t and Th2t of the main refrigerant temperature Th1 at the entrance of the main expansion mechanism 27 (exit of the economizer heat exchanger 32), and the main refrigerant temperature Th1 is set.
- the opening degree of the injection expansion mechanism 33 may be controlled so as to be the target values Th1t and Th2t.
- the target value Th1t is a first main refrigerant target temperature as a target value of the main refrigerant temperature Th1 during the cooling operation
- the target Th2t is a first main refrigerant temperature Th1 as the target value of the main refrigerant temperature Th1 during the heating operation. 2 This is the main refrigerant target temperature.
- the components of the injection expansion mechanism 33 and the sub-refrigerant circuit 80 can be controlled based on the coefficient of performance COP of the main refrigerant circuit 20.
- the gas-liquid separator 51 is a device that separates the main refrigerant into gas and liquid.
- the gas-liquid separator 51 is a container that separates the main refrigerant that has been depressurized in the upstream main expansion mechanism 27 into gas and liquid.
- the gas-liquid separator 51 it is preferable to further provide a gas vent pipe 52 for extracting the main refrigerant in a gaseous state from the gas-liquid separator 51 and sending it to the suction sides of the main compressors 21 and 22.
- the degassing pipe 52 is a refrigerant pipe that sends the gaseous main refrigerant extracted from the gas-liquid separator 51 to the suction side of the first main compressor 21.
- the gas vent pipe 52 is connected to communicate with the upper space of the gas-liquid separator 51, and the other end is connected to the suction side of the first main compressor 21. Further, the gas vent tube 52 has a gas vent expansion mechanism 53.
- the degassing expansion mechanism 53 is a device that depressurizes the main refrigerant, and here is an expansion mechanism that depressurizes the main refrigerant flowing through the degassing pipe 52.
- the gas release expansion mechanism 53 is, for example, an electric expansion valve.
- the cooling operation with the sub-refrigerant circuit cooling operation and the heating operation with the sub-refrigerant circuit heating operation can be performed.
- the main refrigerant in the liquid state from which the main refrigerant in the gas state has been removed in the gas-liquid separator 51 can be sent to the sub-use-side heat exchanger 85.
- the temperature of the main refrigerant can be further reduced.
- the flow rate of the main refrigerant sent to the sub-use-side heat exchanger 85, the main heat source-side heat exchanger 25, and the intermediate heat exchanger 26 is reduced to reduce the pressure loss. LPh) can be further increased.
- the multi-stage compressor is configured by the plurality of main compressors 21 and 22.
- the present invention is not limited to this, and one unit having the compression elements 21a and 21b is provided.
- a multi-stage compressor may be constituted by the main compressor.
- the multi-stage compressor may not be used as the main compressor.
- the main compressor 121 a single-stage compressor including a compression element 121a having an intermediate injection port 121b for introducing a main refrigerant from the outside in the middle of a compression stroke is adopted, and the intermediate injection port 121b is used. May be connected to the injection pipe 31.
- the main refrigerant flowing through the injection pipe 31 can be sent to a middle part (intermediate injection port 121b) of the compression stroke of the main compressor 121 which is a single-stage compressor, the above-described embodiment and Modification 1 As in the cases 4 to 4, the temperature of the main refrigerant compressed to the intermediate pressure (MPh1) in the refrigeration cycle in the main compressor 121 can be reduced.
- the injection pipe 31 is provided in the middle of the compression stroke of the main compressors 21 and 22 and the main compressor 121 (between the low-stage compression element 21a and the high-stage compression element 22a, and so on).
- the main refrigerant is connected to the intermediate injection port 121b) so as to send the main refrigerant thereto.
- the present invention is not limited to this, and the suction side of the first main compressor 21 located at the lowest stage of the multi-stage compressor, the single refrigerant, and the like. It may be connected so as to send the main refrigerant to the suction side of the main compressor 121 composed of a stage compressor.
- the present disclosure branches a refrigerant flowing between a heat source side heat exchanger and a use side heat exchanger into a refrigerant circuit having a compressor, a heat source side heat exchanger, a use side heat exchanger, and a flow path switching mechanism.
- Refrigeration provided with an injection pipe for sending to the compressor, and an economizer heat exchanger for cooling the refrigerant flowing between the heat source side heat exchanger and the use side heat exchanger by heat exchange with the refrigerant flowing through the injection pipe. It is widely applicable to cycle devices.
Abstract
Description
図1は、本開示の一実施形態にかかる冷凍サイクル装置1の概略構成図である。
冷凍サイクル装置1は、メイン冷媒が循環するメイン冷媒回路20と、サブ冷媒が循環するサブ冷媒回路80と、を有しており、室内の空調(ここでは、冷房及び暖房)を行う装置である。
メイン冷媒回路20は、主として、メイン圧縮機21、22と、メイン熱源側熱交換器25と、メイン利用側熱交換器72a、72bと、インジェクション管31と、エコノマイザ熱交換器32と、サブ利用側熱交換器85と、第1メイン流路切換機構23と、を有している。また、メイン冷媒回路20は、中間冷媒管61と、第2メイン流路切換機構24と、中間熱交換器26と、中間熱交バイパス管63と、ブリッジ回路40と、上流側メイン膨張機構27と、メイン利用側膨張機構71a、71bと、を有している。そして、メイン冷媒回路20には、メイン冷媒として、二酸化炭素が封入されている。
サブ冷媒回路80は、主として、サブ圧縮機81と、サブ熱源側熱交換器83と、サブ利用側熱交換器85と、サブ流路切換機構82と、を有している。また、サブ冷媒回路80は、サブ膨張機構84を有している。そして、サブ冷媒回路80には、サブ冷媒として、GWP(温暖化係数)が750以下のHFC冷媒(R32等)、HFO冷媒(R1234yfやR1234ze等)、又は、HFC冷媒とHFO冷媒との混合冷媒(R452B等)が封入されている。尚、サブ冷媒は、これらに限定されるものではなく、二酸化炭素よりも成績係数が高い自然冷媒(プロパンやアンモニア等)であってもよい。
上記のメイン冷媒回路20及びサブ冷媒回路80の構成機器は、熱源ユニット2と、複数の利用ユニット7a、7bと、サブユニット8と、に設けられている。利用ユニット7a、7bはそれぞれ、メイン利用側熱交換器72a、72bに対応して設けられている。
熱源ユニット2は、室外に配置されている。サブ利用側熱交換器85、メイン利用側膨張機構71a、71b及びメイン利用側熱交換器72a、72bを除くメイン冷媒回路20が、熱源ユニット2に設けられている。
利用ユニット7a、7bは、室内に配置されている。メイン冷媒回路20のメイン利用側膨張機構71a、71b及びメイン利用側熱交換器72a、72bが利用ユニット7a、7bに設けられている。
サブユニット8は、室外に配置されている。サブ冷媒回路80、及び、メイン冷媒回路20を構成する冷媒管の一部(サブ利用側熱交換器85に接続されるメイン冷媒が流れる冷媒管の一部)が、サブユニット8に設けられている。
熱源ユニット2と利用ユニット7a、7bとは、メイン冷媒回路20の一部を構成するメイン冷媒連絡管11、12によって接続されている。
そして、上記のメイン冷媒回路20及びサブ冷媒回路80の構成機器を含めた熱源ユニット2、利用ユニット7a、7b及びサブユニット8の構成機器は、制御部9によって制御されるようになっている。制御部9は、熱源ユニット2、利用ユニット7a、7b及びサブユニット8に設けられた制御基板等が通信接続されることによって構成されており、各種センサ34、35、74a、74b、75a、75b、91~99、101~107の検出信号等を受けることができるように構成されている。尚、図1においては、便宜上、熱源ユニット2、利用ユニット7a、7b及びサブユニット8等とは離れた位置に制御部9を図示している。このように、制御部9は、各種センサ34、35、74a、74b、75a、75b、91~99、101~107等の検出信号等に基づいて、冷凍サイクル装置1の構成機器21~24、27、28、33、44、71a、71b、73a、73b、81、82、84、86の制御、すなわち、冷凍サイクル装置1全体の運転制御を行うようになっている。
次に、冷凍サイクル装置1の動作について、図2~図7を用いて説明する。ここで、図2は、冷房運転時における冷凍サイクル装置1内の冷媒の流れを示す図である。図3は、冷房運転時の冷凍サイクルが図示された圧力-エンタルピ線図である。図4は、暖房運転時における冷凍サイクル装置1内の冷媒の流れを示す図である。図5は、暖房運転時の冷凍サイクルが図示された圧力-エンタルピ線図である。図6は、メイン冷媒回路20とサブ冷媒回路80との連動制御を示すフローチャートである。図7は、冷房運転時のメイン膨張機構27の入口におけるメイン冷媒の温度Th1及びサブ利用側熱交換器85の出口におけるサブ冷媒の温度Ts1によるメイン冷媒回路20の成績係数の変化を示す図である。
冷房運転時は、第1メイン流路切換機構23が図2の実線で示されるメイン冷却運転状態に切り換えられ、かつ、第2メイン流路切換機構24が図2の実線で示される中間熱交放熱状態に切り換えられる。また、第1メイン流路切換機構23がメイン冷却運転状態に切り換えられるため、第1下流側メイン膨張機構44が閉じられる。また、冷房運転時は、サブ冷媒回路冷却動作を行うため、サブ流路切換機構82が図2の実線で示されるサブ冷却運転状態に切り換えられる。
暖房運転時は、第1メイン流路切換機構23が図4の破線で示されるメイン加熱運転状態に切り換えられ、かつ、第2メイン流路切換機構24が図4の破線で示される中間熱交バイパス状態に切り換えられる。また、第1メイン流路切換機構23がメイン加熱運転状態に切り換えられるため、第1下流側メイン膨張機構44が開けられる。また、暖房運転時は、サブ冷媒回路加熱動作を行うため、サブ流路切換機構82が図4の破線で示されるサブ加熱運転状態に切り換えられる。
次に、上記のサブ冷媒回路冷却動作を伴う冷房運転時及びサブ冷媒回路加熱動作を伴う暖房運転時におけるメイン冷媒回路20とサブ冷媒回路80との連動制御について説明する。
図6に示すように、制御部9は、ステップST1において、冷房運転が選択されると、ステップST11において、サブ冷媒回路冷却動作を伴う冷房運転が開始されるが、このとき、メイン冷媒回路20においては、インジェクション膨張機構33が所定開度に設定され、サブ冷媒回路80においては、サブ圧縮機81が所定容量、かつ、サブ膨張機構84が所定開度に設定される。
図6に示すように、制御部9は、ステップST1において、冷房運転が選択されると、ステップST12において、サブ冷媒回路加熱動作を伴う暖房運転が開始されるが、このとき、メイン冷媒回路20においては、インジェクション膨張機構33が所定開度に設定され、サブ冷媒回路80においては、サブ圧縮機81が所定容量、かつ、サブ膨張機構84が所定開度に設定される。
次に、冷凍サイクル装置1の特徴について説明する。
ここでは、上記のように、メイン冷媒が循環するメイン冷媒回路20に従来と同様のインジェクション管31及びエコノマイザ熱交換器32を設けるだけでなく、メイン冷媒回路20とは別のサブ冷媒が循環するサブ冷媒回路80を設けている。
また、ここでは、インジェクション管31を流れるメイン冷媒を、多段圧縮機であるメイン圧縮機21、22の圧縮行程の途中部分(低段側圧縮要素21aと高段側圧縮要素22aとの間)に送ることができるため、メイン圧縮機21、22において冷凍サイクルにおける中間圧(MPh1)まで圧縮されたメイン冷媒の温度を低下させることができる。
また、ここでは、上記のように、冷却運転を行う際及び加熱運転を行う際のいずれにおいても、エコノマイザ熱交換器32に、メイン膨張機構27で減圧される前のメイン冷媒を流すことができるため、エコノマイザ熱交換器32におけるメイン冷媒の冷却能力を大きくすることができる。
サブ冷媒回路80がメイン冷媒回路20から独立して制御がなされると、冷房運転を行う際には、エコノマイザ熱交換器32におけるメイン冷媒の冷却熱量(図3の点F、G参照)とサブ利用側熱交換器85におけるメイン冷媒の冷却熱量(図3の点H、I参照)とのバランスが損なわれるおそれがある。また、暖房運転を行う際には、インジェクション管31を流れるメイン冷媒の流量とサブ利用側熱交換器85におけるメイン冷媒の加熱熱量(図5の点H、I)とのバランスが損なわれることがある。
また、ここでは、上記のように、メイン冷媒回路20とサブ冷媒回路80とを連動させる制御を行うにあたり、メイン冷媒回路20の成績係数COPに基づいてインジェクション膨張機構33及びサブ冷媒回路80の構成機器を制御している。
また、ここでは、上記のように、冷却運転を行う際に、メイン冷媒回路20の成績係数COPに基づいてインジェクション膨張機構33及びサブ冷媒回路80の構成機器を制御するにあたり、エコノマイザ熱交換器32の出口におけるインジェクション管31を流れるメイン冷媒の過熱度SHh1に基づいてインジェクション膨張機構33を制御している。
また、ここでは、上記のように、加熱運転を行う際に、メイン冷媒回路20の成績係数COPに基づいてインジェクション膨張機構33及びサブ冷媒回路80の構成機器を制御するにあたり、エコノマイザ熱交換器85の出口におけるインジェクション管31を流れるメイン冷媒の過熱度SHh1に基づいてインジェクション膨張機構33を制御している。
また、ここでは、上記のように、メイン冷媒として二酸化炭素を使用し、サブ冷媒として低GWPの冷媒や二酸化炭素よりも成績係数が高い自然冷媒を使用しているため、地球温暖化等の環境負荷を低減することができる。
<変形例1>
上記実施形態では、ステップST12、ST22において、制御部9が、エコノマイザ熱交換器32の出口におけるインジェクション管31を流れるメイン冷媒の過熱度SHh1に基づいてインジェクション膨張機構33の開度を制御しているが、これに限定されるものではない。
上記実施形態及び変形例1では、上流側メイン膨張機構27において減圧されたメイン冷媒をサブ利用側熱交換器85(第2サブ流路85b)に直接送る構成を採用しているが、これに限定されるものではなく、図8に示すように、上流側メイン膨張機構27とサブ利用側熱交換器85との間に気液分離器51を設けてもよい。
上記実施形態及び変形例1、2では、複数のメイン圧縮機21、22によって、多段圧縮機を構成しているが、これに限定されるものではなく、圧縮要素21a、21bを有する1台のメイン圧縮機によって多段圧縮機を構成してもよい。
上記実施形態及び変形例1~3では、第1メイン圧縮機21と第2メイン圧縮機22との間にメイン冷媒を冷却する中間熱交換器26が設けられた構成を採用しているが、これに限定されるものではなく、中間熱交換器26が設けられていなくてもよい。
上記変形例4のように中間熱交換器26を有しない構成を採用する場合には、多段圧縮機をメイン圧縮機として採用しなくてもよい。例えば、図9に示すように、メイン圧縮機121として、圧縮行程の途中で外部からメイン冷媒を導入する中間インジェクションポート121bを有する圧縮要素121aを含む単段圧縮機を採用し、中間インジェクションポート121bにインジェクション管31を接続してもよい。
上記実施形態及び変形例1~5では、インジェクション管31がメイン圧縮機21、22やメイン圧縮機121の圧縮行程の途中部分(低段側圧縮要素21aと高段側圧縮要素22aとの間や中間インジェクションポート121b)にメイン冷媒を送るように接続されているが、これに限定されるものではなく、多段圧縮機の最も低段側に位置する第1メイン圧縮機21の吸入側や、単段圧縮機からなるメイン圧縮機121の吸入側にメイン冷媒を送るように接続されていてもよい。
9 制御部
20 メイン冷媒回路
21、22、121 メイン圧縮機
21a 低段側圧縮要素
22a 高段側圧縮要素
121a 圧縮要素
121b 中間インジェクションポート
23 第1メイン流路切換機構
25 メイン熱源側熱交換器
26 中間熱交換器
27 上流側メイン膨張機構
31 インジェクション管
32 エコノマイザ熱交換器
33 インジェクション膨張機構
72a、72b メイン利用側熱交換器
80 サブ冷媒回路
81 サブ圧縮機
82 サブ流路切換機構
83 サブ熱源側熱交換器
85 サブ利用側熱交換器
Claims (15)
- メイン冷媒を圧縮するメイン圧縮機(21、22、121)と、
前記メイン冷媒の放熱器又は蒸発器として機能するメイン熱源側熱交換器(25)と、
前記メイン冷媒の蒸発器又は放熱器として機能するメイン利用側熱交換器(72a、72b)と、
前記メイン熱源側熱交換器と前記メイン利用側熱交換器との間を流れる前記メイン冷媒を分岐して前記メイン圧縮機に送るインジェクション管(31)と、
前記メイン熱源側熱交換器と前記メイン利用側熱交換器との間を流れる前記メイン冷媒を前記インジェクション管を流れる前記メイン冷媒との熱交換によって冷却するエコノマイザ熱交換器(32)と、
前記メイン利用側熱交換器が前記メイン冷媒の蒸発器として機能するように前記メイン冷媒を循環させるメイン冷却運転状態と、前記メイン利用側熱交換器が前記メイン冷媒の放熱器として機能するように前記メイン冷媒を循環させるメイン加熱運転状態と、を切り換えるメイン流路切換機構(23)と、
を有する、メイン冷媒回路(20)を備えており、
前記メイン冷媒回路は、前記エコノマイザ熱交換器において冷却された前記メイン冷媒の冷却器又は加熱器として機能するサブ利用側熱交換器(85)を有しており、
サブ冷媒を圧縮するサブ圧縮機(81)と、
前記サブ冷媒の放熱器又は蒸発器として機能するサブ熱源側熱交換器(83)と、
前記サブ冷媒の蒸発器として機能して前記エコノマイザ熱交換器において冷却された前記メイン冷媒を冷却する、又は、前記サブ冷媒の放熱器として機能して前記エコノマイザ熱交換器において冷却された前記メイン冷媒を加熱する、前記サブ利用側熱交換器と、
前記サブ利用側熱交換器が前記サブ冷媒の蒸発器として機能するように前記サブ冷媒を循環させるサブ冷却運転状態と、前記サブ利用側熱交換器が前記サブ冷媒の放熱器として機能するように前記サブ冷媒を循環させるサブ加熱運転状態と、を切り換えるサブ流路切換機構(82)と、
を有する、サブ冷媒回路(80)を備えている、
冷凍サイクル装置(1)。 - 前記メイン圧縮機は、前記メイン冷媒を圧縮する低段側圧縮要素(21a)と、前記低段側圧縮要素から吐出された前記メイン冷媒を圧縮する高段側圧縮要素(22a)と、を含んでおり、
前記メイン冷媒回路は、中間熱交換器(26)を有しており、
前記中間熱交換器は、前記メイン流路切換機構を前記メイン冷却運転状態にしている場合に、前記低段側圧縮要素と前記高段側圧縮要素との間を流れる前記メイン冷媒の冷却器として機能し、前記メイン流路切換機構を前記メイン加熱運転状態にしている場合に、前記サブ利用側熱交換器において加熱された前記メイン冷媒の蒸発器として機能する、
請求項1に記載の冷凍サイクル装置。 - 前記メイン圧縮機は、前記圧縮行程の途中で外部から前記メイン冷媒を導入する中間インジェクションポート(121b)を有する圧縮要素(121a)を含んでおり、
前記インジェクション管は、前記中間インジェクションポートに接続されている、
請求項1に記載の冷凍サイクル装置。 - 前記メイン圧縮機は、前記メイン冷媒を圧縮する低段側圧縮要素(21a)と、前記低段側圧縮要素から吐出された前記メイン冷媒を圧縮する高段側圧縮要素(22a)と、を含んでおり、
前記インジェクション管は、前記高段側圧縮要素の吸入側に接続されている、
請求項1又は2に記載の冷凍サイクル装置。 - 前記メイン冷媒回路は、前記エコノマイザ熱交換器と前記サブ利用側熱交換器との間にメイン膨張機構(27)を有している、
請求項1~4のいずれか1項に記載の冷凍サイクル装置。 - 前記メイン冷媒回路及び前記サブ冷媒回路の構成機器を制御する制御部(9)をさらに備えており、
前記制御部は、前記メイン冷媒回路と前記サブ冷媒回路とが連動するように前記メイン冷媒回路及び前記サブ冷媒回路の構成機器を制御する、
請求項5に記載の冷凍サイクル装置。 - 前記インジェクション管は、インジェクション膨張機構(33)を有しており、
前記制御部は、前記メイン冷媒回路の成績係数に基づいて前記インジェクション膨張機構及び前記サブ冷媒回路の構成機器を制御する、
請求項6に記載の冷凍サイクル装置。 - 前記制御部は、前記メイン流路切換機構を前記メイン冷却運転状態にし、かつ、前記サブ流路切換機構を前記サブ冷却運転状態にしている場合に、前記メイン膨張機構の入口における前記メイン冷媒の温度が第1メイン冷媒目標温度になるように前記インジェクション膨張機構の開度を制御した状態で、前記メイン冷媒回路の成績係数に基づいて前記サブ冷媒回路の構成機器を制御する、
請求項7に記載の冷凍サイクル装置。 - 前記制御部は、前記メイン流路切換機構を前記メイン冷却運転状態にし、かつ、前記サブ流路切換機構を前記サブ冷却運転状態にしている場合に、前記エコノマイザ熱交換器の出口における前記インジェクション管を流れる前記メイン冷媒の過熱度が第1メイン冷媒目標過熱度になるように前記インジェクション膨張機構の開度を制御した状態で、前記メイン冷媒回路の成績係数に基づいて前記サブ冷媒回路の構成機器を制御する、
請求項7に記載の冷凍サイクル装置。 - 前記制御部は、前記メイン膨張機構の入口における前記メイン冷媒の温度と前記メイン冷媒回路の成績係数と前記サブ利用側熱交換器の出口における前記サブ冷媒の温度との相関関係に応じて、前記サブ利用側熱交換器の出口における前記サブ冷媒の温度の目標値である第1サブ冷媒目標温度を設定し、前記サブ利用側熱交換器の出口における前記サブ冷媒の温度が前記第1サブ冷媒目標温度になるように前記サブ冷媒回路の構成機器を制御する、
請求項8又は9に記載の冷凍サイクル装置。 - 前記制御部は、前記メイン流路切換機構を前記メイン加熱運転状態にし、かつ、前記サブ流路切換機構を前記サブ加熱運転状態にしている場合に、前記メイン膨張機構の入口における前記メイン冷媒の温度が第2メイン冷媒目標温度になるように前記インジェクション膨張機構の開度を制御した状態で、前記メイン冷媒回路の成績係数に基づいて前記サブ冷媒回路の構成機器を制御する、
請求項7~10のいずれか1項に記載の冷凍サイクル装置。 - 前記制御部は、前記メイン流路切換機構を前記メイン加熱運転状態にし、かつ、前記サブ流路切換機構を前記サブ加熱運転状態にしている場合に、前記エコノマイザ熱交換器の出口における前記インジェクション管を流れる前記メイン冷媒の過熱度が第2メイン冷媒目標過熱度になるように前記インジェクション膨張機構の開度を制御した状態で、前記メイン冷媒回路の成績係数に基づいて前記サブ冷媒回路の構成機器を制御する、
請求項7~10のいずれか1項に記載の冷凍サイクル装置。 - 前記制御部は、前記メイン膨張機構の入口における前記メイン冷媒の温度と前記メイン冷媒回路の成績係数と前記サブ利用側熱交換器の出口における前記サブ冷媒の温度との相関関係に応じて、前記サブ利用側熱交換器の出口における前記サブ冷媒の温度の目標値である第2サブ冷媒目標温度を設定し、前記サブ利用側熱交換器の出口における前記サブ冷媒の温度が前記第2サブ冷媒目標温度になるように前記サブ冷媒回路の構成機器を制御する、
請求項11又は12に記載の冷凍サイクル装置。 - 前記メイン冷媒は、二酸化炭素であり、
前記サブ冷媒は、GWPが750以下のHFC冷媒、HFO冷媒、又は、HFC冷媒とHFO冷媒との混合冷媒である、
請求項1~13のいずれか1項に記載の冷凍サイクル装置。 - 前記メイン冷媒は、二酸化炭素であり、
前記サブ冷媒は、二酸化炭素よりも成績係数が高い自然冷媒である、
請求項1~13のいずれか1項に記載の冷凍サイクル装置。
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