WO2022075358A1 - Heat source unit and control method therefor - Google Patents

Heat source unit and control method therefor Download PDF

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Publication number
WO2022075358A1
WO2022075358A1 PCT/JP2021/036974 JP2021036974W WO2022075358A1 WO 2022075358 A1 WO2022075358 A1 WO 2022075358A1 JP 2021036974 W JP2021036974 W JP 2021036974W WO 2022075358 A1 WO2022075358 A1 WO 2022075358A1
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WO
WIPO (PCT)
Prior art keywords
refrigerant
expansion valve
heat exchanger
heat
heat medium
Prior art date
Application number
PCT/JP2021/036974
Other languages
French (fr)
Japanese (ja)
Inventor
正広 寺岡
Original Assignee
三菱重工サーマルシステムズ株式会社
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Filing date
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Application filed by 三菱重工サーマルシステムズ株式会社 filed Critical 三菱重工サーマルシステムズ株式会社
Priority to EP21877657.3A priority Critical patent/EP4177545A4/en
Publication of WO2022075358A1 publication Critical patent/WO2022075358A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B13/00—Compression machines, plants or systems, with reversible cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • 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
    • F25B31/00—Compressor arrangements
    • F25B31/006—Cooling of compressor or motor
    • F25B31/008—Cooling of compressor or motor by injecting a liquid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/30—Expansion means; Dispositions thereof
    • F25B41/385—Dispositions with two or more expansion means arranged in parallel on a refrigerant line leading to the same evaporator
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/30—Expansion means; Dispositions thereof
    • F25B41/39—Dispositions with two or more expansion means arranged in series, i.e. multi-stage expansion, on a refrigerant line leading to the same evaporator
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
    • F25B2313/003—Indoor unit with water as a heat sink or heat source
    • 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
    • F25B2400/04—Refrigeration circuit bypassing means
    • F25B2400/0411—Refrigeration circuit bypassing means for the expansion valve or capillary tube
    • 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
    • F25B2400/04—Refrigeration circuit bypassing means
    • F25B2400/0415—Refrigeration circuit bypassing means for the receiver
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2500/00—Problems to be solved
    • F25B2500/31—Low ambient temperatures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/25—Control of valves
    • F25B2600/2513—Expansion valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/25—Control of valves
    • F25B2600/2519—On-off valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2106—Temperatures of fresh outdoor air
    • 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 present disclosure relates to a heat source machine suitable for use in, for example, a heat pump chiller and a control method thereof.
  • a heat pump chiller is used as one of the heat source machines for industrial use.
  • the pressure ratio tends to be high and the temperature of the refrigerant discharged from the compressor tends to be high, especially when the outside air temperature is low.
  • a low boiling point refrigerant such as R32 is used as the refrigerant having a low global warming potential (GWP)
  • GWP global warming potential
  • the refrigerant discharge temperature becomes higher.
  • the refrigerant discharge temperature becomes high, it becomes difficult to divert the conventional parts used for the refrigerant that is not a low boiling point refrigerant, so that it is required to reduce the refrigerant discharge temperature.
  • Patent Document 1 a part of the refrigerant derived from the indoor unit is expanded by a throttle device to form a gas-liquid two-phase, and the two-phase refrigerant is supplied to the refrigerant suction side of the compressor to control the refrigerant discharge temperature. It is disclosed to reduce.
  • Patent Document 1 since a refrigerant having two phases of gas and liquid is used as the cooling refrigerant, the specific volume of the refrigerant becomes larger than that of the liquid refrigerant, and the pipe diameter becomes large. This not only does not improve the maneuverability, but also cannot reduce the cost.
  • Patent Document 1 a throttle device is provided in a pipe for guiding a gas-liquid two-phase refrigerant for cooling, and the opening degree thereof is controlled.
  • a throttle device is provided in a pipe for guiding a gas-liquid two-phase refrigerant for cooling, and the opening degree thereof is controlled.
  • it is complicated to control the opening degree of the throttle device in addition to controlling the expansion valve of the main refrigerant circuit.
  • the present disclosure has been made in view of such circumstances, and provides a heat source machine capable of reducing the diameter of a pipe for supplying a cooling refrigerant leading to a suction side of a compressor and a control method thereof.
  • Another object of the present invention is to provide a heat source machine capable of reducing the amount of refrigerant used even in a heat source machine performing a heating operation and a cooling operation, and a control method thereof.
  • Another object of the present invention is to provide a heat source machine capable of supplying a cooling refrigerant to the suction side of a compressor with simple control and a control method thereof.
  • the heat source machine includes a compressor for compressing a refrigerant, a heat medium heat exchanger for heat exchange between the refrigerant and the heat medium, and an expansion valve for expanding the refrigerant.
  • An air heat exchanger that exchanges heat between the refrigerant and air, a liquid bypass pipe in which an upstream end is connected between the heat medium heat exchanger and the expansion valve to guide the liquid refrigerant to the suction side of the compressor. Is equipped with.
  • the heat source machine control method includes a compressor that compresses the refrigerant, a heat medium heat exchanger that exchanges heat between the refrigerant and the heat medium, an expansion valve that expands the refrigerant, and the refrigerant and air.
  • the liquid bypass valve provided in the above and the refrigerant discharged from the compressor during the heating operation for heating the heat medium are guided to the heat medium heat exchanger, and from the compressor during the cooling operation for cooling the heat medium.
  • the liquid bypass valve is controlled from closed to open.
  • the diameter of the pipe that supplies the cooling refrigerant that leads to the suction side of the compressor can be reduced. Even a heat source machine that performs heating operation and cooling operation can reduce the amount of refrigerant used. Cooling refrigerant can be supplied to the suction side of the compressor with simple control.
  • FIG. 5 is a schematic configuration diagram showing a refrigerant circuit according to the first embodiment of the present disclosure and during a heating operation. It is the refrigerant circuit which concerns on 1st Embodiment of this disclosure, and is the schematic block diagram which showed the time of cooling operation.
  • FIG. 5 is a schematic configuration diagram showing a refrigerant circuit according to a second embodiment of the present disclosure and during a heating operation.
  • FIG. 5 is a schematic configuration diagram showing a cooling operation of the refrigerant circuit according to the second embodiment of the present disclosure. It is a graph which showed the ph diagram of the refrigerant circuit which concerns on 3rd Embodiment of this disclosure. It is a schematic block diagram which showed the refrigerant circuit which showed the modification of the 3rd Embodiment of this disclosure.
  • FIGS. 1 and 2 show a refrigerant circuit configuration of the chiller (heat source machine) 1 of the present embodiment.
  • the chiller 1 can perform a heating operation and a cooling operation by switching the four-way valve (switching valve) 4 provided on the discharge side of the compressor 3.
  • the heating operation is an operation of heating water (heat medium) with a water heat exchanger (heat medium heat exchanger) 5, and a cooling operation is an operation of cooling water with a water heat exchanger 5.
  • FIG. 1 shows a refrigerant circuit in the case of performing a heating operation
  • FIG. 2 shows a refrigerant circuit in the case of performing a cooling operation.
  • R32 is used as the refrigerant.
  • R32 is a low boiling point refrigerant and has a low global warming potential (GWP).
  • GWP global warming potential
  • Another refrigerant may be used instead of R32.
  • the chiller 1 includes a compressor 3 for compressing the refrigerant, a four-way valve 4, a water heat exchanger 5, a first expansion valve 6, a receiver 7, a second expansion valve 8, an air heat exchanger 9, and the like. It includes an accumulator 10.
  • a refrigeration cycle is performed by connecting the compressor 3, the four-way valve 4, the water heat exchanger 5, the first expansion valve 6, the receiver 7, the second expansion valve 8, the air heat exchanger 9, and the accumulator 10 by a refrigerant pipe.
  • a refrigerant circuit is configured.
  • the compressor 3 is, for example, a scroll compressor or a rotary compressor, and a compression mechanism 3b such as a scroll compression mechanism or a rotary compression mechanism is provided in the housing 3a of the compressor 3.
  • the compression mechanism 3b is driven by an electric motor (not shown).
  • the electric motor includes an inverter device, and the rotation speed is arbitrarily changed by a command from a control unit (not shown).
  • a discharge temperature sensor 14 for measuring the discharge temperature of the refrigerant is provided on the discharge side of the compressor 3. The output of the discharge temperature sensor 14 is transmitted to the control unit.
  • the four-way valve 4 is switched so that the refrigerant discharged from the compressor 3 is guided to the water heat exchanger 5 during the heating operation (FIG. 1), and the refrigerant discharged from the compressor 3 is guided to the air heat exchanger during the cooling operation. It is switched to be guided to 9 (Fig. 2).
  • the control of the four-way valve 4 is performed by a control unit (not shown).
  • the water heat exchanger 5 operates as a condenser during the heating operation (FIG. 1) and as an evaporator during the cooling operation (FIG. 2).
  • a water pipe 16 for circulating water with an external load is connected to the water heat exchanger 5.
  • the water heat exchanger 5 exchanges heat between the water guided from the water pipe 16 and the refrigerant.
  • the first expansion valve 6 expands the refrigerant liquefied by the water heat exchanger 5 when operating as a condenser as shown in FIG.
  • the opening degree of the first expansion valve 6 is controlled by the control unit.
  • the second expansion valve 8 expands the refrigerant liquefied by the air heat exchanger 9 when operating as a condenser as shown in FIG.
  • the opening degree of the second expansion valve 8 is controlled by the control unit.
  • the receiver 7 is a container provided between the first expansion valve 6 and the second expansion valve 8 and temporarily stores a part of the refrigerant expanded by the first expansion valve 6 or the second expansion valve 8. ..
  • the capacity (magnitude) of the receiver 7 is determined according to the amount of refrigerant circulating in the refrigerant circuit.
  • the air heat exchanger 9 operates as an evaporator during the heating operation (FIG. 1) and as a condenser during the cooling operation (FIG. 2).
  • the air heat exchanger 9 exchanges heat between the refrigerant and air. Air is sent from the fan 12 to the air heat exchanger 9.
  • the accumulator 10 is a container provided on the upstream side of the compressor 3, that is, the refrigerant suction side, and temporarily stores the refrigerant evaporated by the air heat exchanger 9 or the water heat exchanger 5.
  • the upstream end of the liquid bypass pipe 20 is connected between the water heat exchanger 5 and the first expansion valve 6.
  • the downstream end of the liquid bypass pipe 20 is connected to the suction side of the compression mechanism 3b of the compressor 3.
  • the liquid bypass valve 22 a part of the liquid refrigerant guided from the water heat exchanger 5 that operates as a condenser during the heating operation is guided to the compression mechanism 3b. That is, the liquid bypass valve 22 bypasses the first expansion valve 6, the receiver 7, the second expansion valve 8, the air heat exchanger 9, and the accumulator 10.
  • a liquid bypass valve 22 is provided in the middle of the liquid bypass pipe 20.
  • the liquid bypass valve 22 is an on-off valve such as a solenoid valve, and the opening / closing operation is performed by the control unit.
  • An outside air temperature sensor 18 is provided in the housing of the chiller 1 or in the vicinity of the chiller 1.
  • the outside air temperature is measured by the outside air temperature sensor.
  • the outside air temperature measured by the outside air temperature sensor 18 is taken as the air temperature guided to the air heat exchanger 9 by the fan 12.
  • the output of the outside air temperature sensor 18 is transmitted to the control unit.
  • the control unit is composed of, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a computer-readable storage medium, and the like.
  • a series of processes for realizing various functions are stored in a storage medium or the like in the form of a program, and the CPU reads this program into a RAM or the like to execute information processing / arithmetic processing.
  • the program may be installed in a ROM or other storage medium in advance, provided in a state of being stored in a computer-readable storage medium, or distributed via a wired or wireless communication means. May be applied.
  • the computer-readable storage medium is a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like.
  • Fig. 1 When the water is heated by the water heat exchanger 5, the four-way valve 4 is switched as shown in FIG. 1, and the high-pressure gas refrigerant discharged from the compressor 3 is guided to the water heat exchanger 5. In the water heat exchanger 5, the refrigerant is condensed by exchanging heat with the water guided from the water pipe 16. Water is heated by the latent heat of condensation of the refrigerant. The heated water is guided to an external load via the water pipe 16.
  • the liquid refrigerant condensed in the water heat exchanger 5 is guided to the first expansion valve 6 and expanded.
  • the expanded refrigerant is guided to the receiver 7, and a part of the refrigerant is stored in the receiver 7 as a surplus refrigerant.
  • the refrigerant taken out from the receiver 7 is guided to the air heat exchanger 9 via the second expansion valve 8.
  • the refrigerant evaporates by exchanging heat with the air guided by the fan 12.
  • the refrigerant evaporated in the air heat exchanger 9 is guided to the accumulator 10 through the four-way valve 4.
  • the gas refrigerant guided from the accumulator 10 is guided to the suction side of the compressor 3 and is compressed again by the compression mechanism 3b.
  • the control unit has a liquid bypass valve 22 provided in the liquid bypass pipe 20 when the outside air temperature measured by the outside air temperature sensor 18 becomes a low outside air temperature of a predetermined value or less (for example, 0 ° C. or less or -5 ° C. or less). Is controlled from closed to open. As a result, a part of the liquid refrigerant guided from the water heat exchanger 5 is guided to the suction side of the compression mechanism 3b of the compressor 3 via the liquid bypass pipe 20. By supplying the liquid refrigerant to the suction side of the compression mechanism 3b in this way, the discharge temperature of the refrigerant discharged from the compressor 3 is reduced.
  • a predetermined value or less for example, 0 ° C. or less or -5 ° C. or less
  • the control of opening and closing of the liquid bypass valve 22 is performed together with the temperature measured by the outside air temperature sensor 18, or instead of the temperature measured by the outside air temperature sensor 18, the temperature measured by the discharge temperature sensor 14 or the compressor 3
  • the pressure ratio of may be used. For example, when the measured value of the discharge temperature sensor 14 reaches a temperature corresponding to 50 ° C. of the water temperature heated by the water heat exchanger 5, and / or the pressure ratio of the compressor 3 becomes 4.5 or more. At that time, the liquid bypass valve 22 is controlled from closed to open.
  • the liquid refrigerant condensed in the air heat exchanger 9 is guided to the second expansion valve 8 and expanded.
  • the expanded refrigerant is guided to the receiver 7, and a part of the refrigerant is stored in the receiver 7.
  • the refrigerant taken out from the receiver 7 is guided to the water heat exchanger 5 via the first expansion valve 6.
  • the refrigerant evaporates by exchanging heat with the water guided from the water pipe 16.
  • the water cooled by the latent heat of vaporization of the refrigerant is guided to an external load via the water pipe 16.
  • the refrigerant evaporated in the water heat exchanger 5 is guided to the accumulator 10 through the four-way valve 4.
  • the gas refrigerant guided from the accumulator 10 is guided to the suction side of the compressor 3 and is compressed again by the compression mechanism 3b.
  • the control unit keeps the liquid bypass valve 22 closed during the cooling operation. That is, the liquid bypass pipe 20 is not used during the cooling operation.
  • the following effects are exhibited.
  • the temperature of the refrigerant discharged from the compressor 3 can be lowered.
  • This enables operation at a high pressure ratio and expands the range of use of the chiller 1. Since the liquid refrigerant flows through the liquid bypass pipe 20, the diameter (inner diameter of the pipe) can be made smaller than that of the two-phase refrigerant mixed with the gas refrigerant. As a result, the cost can be reduced and the piping can be easily routed.
  • the upstream end of the liquid bypass pipe 20 is provided between the water heat exchanger 5 and the first expansion valve 6.
  • the refrigerant before expansion can be reliably guided to the compressor 3 as a liquid refrigerant. Since a part of the liquid refrigerant is bypassed to the compressor 3 by the liquid bypass pipe 20, the capacity (size) of the receiver 7 provided between the first expansion valve 6 and the second expansion valve 8 is reduced. be able to. As a result, space can be saved and costs can be reduced.
  • a high pressure ratio (for example, 4.5 or more) may occur and the temperature of the refrigerant discharged from the compressor 3 may become high. Therefore, under such conditions, the liquid bypass valve 22 is opened to guide the liquid refrigerant to the suction side of the compression mechanism 3b.
  • a refrigerant pipe 30 is provided.
  • the parallel refrigerant pipe 30 is provided in parallel with the first expansion valve 6, the receiver 7, and the second expansion valve 8. As a result, the parallel refrigerant pipe 30 bypasses the first expansion valve 6, the receiver 7, and the second expansion valve 8 to connect the water heat exchanger 5 and the air heat exchanger 9.
  • the parallel refrigerant pipe 30 is provided with a third expansion valve 32.
  • the opening degree of the third expansion valve is controlled by the control unit.
  • the chiller 1 of the present embodiment has the following effects. It was decided to provide the parallel refrigerant pipe 30 in parallel with the first expansion valve 6, the receiver 7, and the second expansion valve 8. Then, during the heating operation, the third expansion valve 32 is closed so that the refrigerant flows to the first expansion valve 6 side. As a result, the excess refrigerant can be stored in the receiver 7 during the heating operation.
  • the third expansion valve 32 was opened so that the refrigerant flowed through the parallel refrigerant pipe 30 and the refrigerant did not flow on the second expansion valve 8 side.
  • the necessary refrigerant can be used in just proportion without storing the refrigerant in the receiver 7 during the cooling operation.
  • the refrigerant is expanded by the third expansion valve 32, and can be expanded by one expansion valve. Therefore, if only the third expansion valve 32 is used in the parallel refrigerant pipe 30, the high and low differential pressure (with the water heat exchanger 5) is compared with the case of expanding with the first expansion valve 6 and the second expansion valve 8.
  • the refrigerant differential pressure of the air heat exchanger 9) is relatively small, it is possible to avoid an insufficient diameter of the expansion valve.
  • the control unit of the present embodiment controls the opening degree of the first expansion valve 6 so that the temperature of the refrigerant discharged from the compressor 3 becomes a predetermined value or less during the heating operation shown in FIGS. 1 and 3. Specifically, when the measured value of the discharge temperature sensor 14 exceeds a predetermined value, the opening degree of the first expansion valve 6 is narrowed down in the closing direction.
  • the predetermined value means, for example, the temperature measured by the discharge temperature sensor 14 corresponding to the case where the water temperature heated by the water heat exchanger 5 is 50 ° C., or a temperature several ° C. lower than the measured temperature. do.
  • the amount of refrigerant circulation is reduced, the condensation capacity of the water heat exchanger 5 is increased, the liquid phase ratio of the refrigerant is increased, and the compressor passes through the liquid bypass pipe 20. Increase the amount of liquid refrigerant leading to 3. Then, the amount of the liquid refrigerant guided to the suction side of the compressor 3 increases, so that the discharge gas temperature decreases.
  • the refrigerant before narrowing the opening degree of the first expansion valve 6 merges from the C2 point through the D2 point and the L2 point at the S2 point (specific enthalpy HS2). Then, the refrigerant compressed by the compression mechanism 3b reaches the point B2.
  • the temperature at the B1 point where the opening degree of the first expansion valve 6 is narrowed is lower than that at the B2 point, and the discharge temperature is lower.
  • the discharge temperature can be lowered without controlling the opening degree of the liquid bypass valve 22.
  • FIG. 6 corresponds to FIG. 1, and the position of the upstream end of the liquid bypass pipe 20 is different.
  • the configuration is the same as in FIG.
  • the upstream end of the liquid bypass pipe 20 is connected between the first expansion valve 6 and the receiver 7. Even with such a configuration, it is possible to control the discharge refrigerant temperature by the first expansion valve 6 as in the present embodiment described above.
  • (1) includes a compressor (3) for compressing the refrigerant, a heat medium heat exchanger (5) for heat exchange between the refrigerant and the heat medium, and an expansion of the refrigerant.
  • An upstream end is connected between the expansion valve (6), an air heat exchanger (9) that exchanges heat between the refrigerant and air, and the heat medium heat exchanger and the expansion valve, and the liquid refrigerant is used in the compressor. It is provided with a liquid bypass pipe (20) leading to the suction side of the.
  • the temperature of the refrigerant discharged from the compressor can be lowered. This enables operation at a high pressure ratio and expands the range of use of the heat source machine. Since the liquid refrigerant flows through the liquid bypass pipe, the diameter (inner diameter of the pipe) can be made smaller than that of the two-phase refrigerant mixed with the gas refrigerant. As a result, the cost can be reduced and the piping can be easily routed.
  • the expansion valve includes a first expansion valve provided on the heat medium heat exchanger side and a second expansion valve provided on the air heat exchanger side. 8), the upstream end of the liquid bypass pipe is connected between the heat medium heat exchanger and the first expansion valve, and between the first expansion valve and the second expansion valve. , A receiver (7) for storing the refrigerant is provided.
  • the upstream end of the liquid bypass pipe is provided between the heat medium heat exchanger and the first expansion valve.
  • the refrigerant before expansion can be reliably guided to the compressor as a liquid refrigerant. Since a part of the liquid refrigerant is bypassed to the compressor by the liquid bypass pipe, the capacity of the receiver provided between the first expansion valve and the second expansion valve can be reduced. As a result, space can be saved and costs can be reduced.
  • a switching valve that guides the refrigerant discharged from the compressor to the air heat exchanger, a liquid bypass valve (22) provided in the liquid bypass pipe, and the air heat exchanger during the heating operation. It is provided with a control unit for controlling the liquid bypass valve from closed to open when the ambient air temperature is equal to or lower than a predetermined value.
  • the pressure ratio becomes high (for example, 4.5 or more) and the temperature of the refrigerant discharged from the compressor is high. There is a risk of becoming. Therefore, under such conditions, the liquid bypass valve is opened to guide the liquid refrigerant to the suction side of the compressor.
  • the heat source machine during the cooling operation in which the refrigerant discharged from the compressor is guided to the heat medium heat exchanger during the heating operation for heating the heat medium and the heat medium is cooled.
  • the opening degree of the first expansion valve and / or the second expansion valve is controlled so that the refrigerant flows to the first expansion valve side, the third expansion valve is opened during the cooling operation, and the second expansion valve is opened. It is provided with a control unit for controlling the opening degree of the first expansion valve and / or the second expansion valve so that the refrigerant does not flow to the side.
  • the refrigerant is expanded by the third expansion valve, and can be expanded by one expansion valve. Therefore, if the third expansion valve is used in the parallel refrigerant pipe, the differential pressure (heat medium heat exchanger and air heat exchanger) is higher and lower than when the third expansion valve is used to expand the first expansion valve and the second expansion valve. When the refrigerant differential pressure) is relatively small, it is possible to avoid an insufficient diameter of the expansion valve.
  • a switching valve that guides the refrigerant discharged from the compressor to the air heat exchanger, a liquid bypass valve provided in the liquid bypass pipe and used as an on-off valve, and a liquid bypass valve that is discharged from the compressor during the heating operation. It is provided with a control unit for controlling the opening degree of the first expansion valve so that the temperature of the refrigerant becomes equal to or lower than a predetermined value.
  • the opening degree of the first expansion valve By controlling the opening degree of the first expansion valve, the temperature of the refrigerant discharged from the compressor is controlled to a predetermined value or less. As a result, it is possible to adopt an on-off valve that only opens and closes the valve instead of the adjusting valve that has a variable valve opening as the liquid bypass valve, and the cost can be reduced. Further, since it is not necessary to adjust the opening degree of the liquid bypass valve, the control can be simplified.
  • the heat source machine control method includes a compressor that compresses the refrigerant, a heat medium heat exchanger that exchanges heat between the refrigerant and the heat medium, an expansion valve that expands the refrigerant, and the refrigerant and air.
  • the liquid bypass valve provided in the above and the refrigerant discharged from the compressor during the heating operation for heating the heat medium are guided to the heat medium heat exchanger, and from the compressor during the cooling operation for cooling the heat medium.
  • the liquid bypass valve is controlled from closed to open.
  • the heat source machine control method includes a compressor that compresses the refrigerant, a heat medium heat exchanger that exchanges heat between the refrigerant and the heat medium, and an air heat exchanger that exchanges heat between the refrigerant and air. Between the first expansion valve provided on the heat medium heat exchanger side, the second expansion valve provided on the air heat exchanger side, and the heat medium heat exchanger and the first expansion valve. Between the liquid bypass pipe that is connected to the upstream end and guides the liquid refrigerant to the suction side of the compressor, the liquid bypass valve provided in the liquid bypass pipe, and the first expansion valve and the second expansion valve.
  • a receiver for storing the refrigerant and the refrigerant discharged from the compressor during the heating operation for heating the heat medium are guided to the heat medium heat exchanger, and the compression is performed during the cooling operation for cooling the heat medium.
  • a switching valve that guides the refrigerant discharged from the machine to the air heat exchanger is provided in parallel with the first expansion valve, the receiver, and the second expansion valve, and the heat medium heat exchanger and the said. It is a control method of a heat source machine including a parallel refrigerant pipe connecting an air heat exchanger and a third expansion valve provided in the parallel refrigerant pipe, and the third expansion valve is used during the heating operation.
  • the opening of the first expansion valve and / or the second expansion valve is controlled so as to be closed and the refrigerant flows to the first expansion valve side, and the third expansion valve is opened during the cooling operation.
  • the opening degree of the first expansion valve and / or the second expansion valve is controlled so that the refrigerant does not flow to the second expansion valve side.
  • the heat source machine control method includes a compressor that compresses the refrigerant, a heat medium heat exchanger that exchanges heat between the refrigerant and the heat medium, and an air heat exchanger that exchanges heat between the refrigerant and air. Between the first expansion valve provided on the heat medium heat exchanger side, the second expansion valve provided on the air heat exchanger side, and the heat medium heat exchanger and the first expansion valve. Between the liquid bypass pipe that is connected to the upstream end and guides the liquid refrigerant to the suction side of the compressor, the liquid bypass valve provided in the liquid bypass pipe, and the first expansion valve and the second expansion valve.
  • a receiver for storing the refrigerant and the refrigerant discharged from the compressor during the heating operation for heating the heat medium are guided to the heat medium heat exchanger, and the compression is performed during the cooling operation for cooling the heat medium. It is a control method of a heat source machine equipped with a switching valve for guiding the refrigerant discharged from the machine to the air heat exchanger, and the temperature of the refrigerant discharged from the compressor during the heating operation is equal to or lower than a predetermined value.
  • the opening degree of the first expansion valve is controlled so as to be.
  • Chiller (heat source machine) 3 Compressor 3a Housing 3b Compression mechanism 4 Four-way valve (switching valve) 5 Water heat exchanger (heat medium heat exchanger) 6 1st expansion valve 7 Receiver 8 2nd expansion valve 9 Air heat exchanger 10 Accumulator 12 Fan 14 Discharge temperature sensor 16 Water piping 18 Outside temperature sensor 20 Liquid bypass piping 22 Liquid bypass valve 30 Parallel refrigerant piping 32 3rd expansion valve

Abstract

Provided is a heat source unit whereby the diameter of pipes that supply cooling refrigerant to be guided into an intake side of a compressor can be reduced. A chiller (1) comprises: a compressor (3) that compresses refrigerant; a water heat exchanger (5) that exchanges heat between the refrigerant and water; a first expansion valve (6) that expands the refrigerant; an air heat exchanger (9) that exchanges heat between the refrigerant and air; and a fluid bypass pipe (20) that has an upstream end thereof connected to between the water heat exchanger (5) and the first expansion valve (6) and guides the fluid refrigerant to the intake side of the compressor (3). A second expansion valve (8) is provided on the air heat exchanger (9) side and a receiver (7) is provided between the first expansion valve (6) and a second expansion valve (8).

Description

熱源機及びその制御方法Heat source machine and its control method
　本開示は、例えばヒートポンプチラー等に用いて好適な熱源機及びその制御方法に関する。 The present disclosure relates to a heat source machine suitable for use in, for example, a heat pump chiller and a control method thereof.
　産業用などの熱源機の一つとしてヒートポンプチラーが用いられている。ヒートポンプチラーを加熱運転で用いて温水を供給する場合、特に外気温が低いと高圧力比となり圧縮機から吐出される冷媒の温度が高くなる傾向にある。地球温暖化係数（ＧＷＰ）が低い冷媒としてＲ３２等の低沸点冷媒を用いた場合、さらに冷媒吐出温度が高くなる。冷媒吐出温度が高くなると、低沸点冷媒でない冷媒に対して用いられていた従来部品の流用が困難となるため、冷媒吐出温度を低減させることが要請される。 A heat pump chiller is used as one of the heat source machines for industrial use. When hot water is supplied by using a heat pump chiller in a heating operation, the pressure ratio tends to be high and the temperature of the refrigerant discharged from the compressor tends to be high, especially when the outside air temperature is low. When a low boiling point refrigerant such as R32 is used as the refrigerant having a low global warming potential (GWP), the refrigerant discharge temperature becomes higher. When the refrigerant discharge temperature becomes high, it becomes difficult to divert the conventional parts used for the refrigerant that is not a low boiling point refrigerant, so that it is required to reduce the refrigerant discharge temperature.
　特許文献１には、室内機から導かれた冷媒の一部を絞り装置で膨張させて気液二相とし、この二相冷媒を圧縮機の冷媒吸込側に供給することで、冷媒吐出温度を低減させることが開示されている。 In Patent Document 1, a part of the refrigerant derived from the indoor unit is expanded by a throttle device to form a gas-liquid two-phase, and the two-phase refrigerant is supplied to the refrigerant suction side of the compressor to control the refrigerant discharge temperature. It is disclosed to reduce.
特許第６００５２５５号公報Japanese Patent No. 6002555
　しかし、特許文献１では、冷却用の冷媒として気液二相とされた冷媒を用いているので、冷媒の比体積が液冷媒に比べて大きくなり配管径が大きくなってしまう。これでは取り回し性が改善されないだけでなく、コストを低減することができない。 However, in Patent Document 1, since a refrigerant having two phases of gas and liquid is used as the cooling refrigerant, the specific volume of the refrigerant becomes larger than that of the liquid refrigerant, and the pipe diameter becomes large. This not only does not improve the maneuverability, but also cannot reduce the cost.
　ヒートポンプによる加熱運転に加えて冷却運転も行う場合、必要とされる冷媒量が各運転で異なるため使用する冷媒が余剰となるという問題がある。 When the cooling operation is performed in addition to the heating operation by the heat pump, there is a problem that the amount of the required refrigerant differs in each operation, so that the refrigerant used becomes surplus.
　特許文献１では、冷却用の気液二相冷媒を導く配管に絞り装置を設け、その開度を制御するようになっている。しかし、メインの冷媒回路の膨張弁制御に加えて絞り装置の開度制御を行うのは煩雑である。 In Patent Document 1, a throttle device is provided in a pipe for guiding a gas-liquid two-phase refrigerant for cooling, and the opening degree thereof is controlled. However, it is complicated to control the opening degree of the throttle device in addition to controlling the expansion valve of the main refrigerant circuit.
　本開示は、このような事情に鑑みてなされたものであって、圧縮機の吸込側に導く冷却用の冷媒を供給する配管径を小さくすることができる熱源機及びその制御方法を提供することを目的とする。
　また、加熱運転及び冷却運転を行う熱源機であっても使用冷媒量を低減することができる熱源機及びその制御方法を提供することを目的とする。
　また、簡便な制御で冷却用の冷媒を圧縮機の吸込側に供給することができる熱源機及びその制御方法を提供することを目的とする。 The present disclosure has been made in view of such circumstances, and provides a heat source machine capable of reducing the diameter of a pipe for supplying a cooling refrigerant leading to a suction side of a compressor and a control method thereof. With the goal.
Another object of the present invention is to provide a heat source machine capable of reducing the amount of refrigerant used even in a heat source machine performing a heating operation and a cooling operation, and a control method thereof.
Another object of the present invention is to provide a heat source machine capable of supplying a cooling refrigerant to the suction side of a compressor with simple control and a control method thereof.
　本開示の熱源機は、本開示の一態様に係る熱源機は、冷媒を圧縮する圧縮機と、冷媒と熱媒体とを熱交換する熱媒体熱交換器と、冷媒を膨張させる膨張弁と、冷媒と空気とを熱交換する空気熱交換器と、前記熱媒体熱交換器と前記膨張弁との間に上流端が接続されて液冷媒を前記圧縮機の吸入側に導く液バイパス配管と、を備えている。 The heat source machine according to the present disclosure includes a compressor for compressing a refrigerant, a heat medium heat exchanger for heat exchange between the refrigerant and the heat medium, and an expansion valve for expanding the refrigerant. An air heat exchanger that exchanges heat between the refrigerant and air, a liquid bypass pipe in which an upstream end is connected between the heat medium heat exchanger and the expansion valve to guide the liquid refrigerant to the suction side of the compressor. Is equipped with.
　本開示の一態様に係る熱源機の制御方法は、冷媒を圧縮する圧縮機と、冷媒と熱媒体とを熱交換する熱媒体熱交換器と、冷媒を膨張させる膨張弁と、冷媒と空気とを熱交換する空気熱交換器と、前記熱媒体熱交換器と前記膨張弁との間に上流端が接続されて液冷媒を前記圧縮機の吸入側に導く液バイパス配管と、前記液バイパス配管に設けられた液バイパス弁と、前記熱媒体を加熱する加熱運転時に前記圧縮機から吐出された冷媒を前記熱媒体熱交換器へと導き、前記熱媒体を冷却する冷却運転時に前記圧縮機から吐出された冷媒を前記空気熱交換器へと導く切換弁と、を備えた熱源機の制御方法であって、前記加熱運転時で、かつ、前記空気熱交換器の周囲の空気温度が所定値以下とされた場合に、前記液バイパス弁を閉から開へと制御する。 The heat source machine control method according to one aspect of the present disclosure includes a compressor that compresses the refrigerant, a heat medium heat exchanger that exchanges heat between the refrigerant and the heat medium, an expansion valve that expands the refrigerant, and the refrigerant and air. A liquid bypass pipe in which an upstream end is connected between the heat medium heat exchanger and the expansion valve to guide the liquid refrigerant to the suction side of the compressor, and the liquid bypass pipe. The liquid bypass valve provided in the above and the refrigerant discharged from the compressor during the heating operation for heating the heat medium are guided to the heat medium heat exchanger, and from the compressor during the cooling operation for cooling the heat medium. It is a control method of a heat source machine provided with a switching valve for guiding the discharged refrigerant to the air heat exchanger, and the air temperature around the air heat exchanger is a predetermined value during the heating operation. In the following cases, the liquid bypass valve is controlled from closed to open.
　圧縮機の吸込側に導く冷却用の冷媒を供給する配管径を小さくすることができる。
　加熱運転及び冷却運転を行う熱源機であっても使用冷媒量を低減することができる。
　簡便な制御で冷却用の冷媒を圧縮機の吸込側に供給することができる。 The diameter of the pipe that supplies the cooling refrigerant that leads to the suction side of the compressor can be reduced.
Even a heat source machine that performs heating operation and cooling operation can reduce the amount of refrigerant used.
Cooling refrigerant can be supplied to the suction side of the compressor with simple control.
本開示の第１実施形態に係る冷媒回路であり加熱運転時を示した概略構成図である。FIG. 5 is a schematic configuration diagram showing a refrigerant circuit according to the first embodiment of the present disclosure and during a heating operation. 本開示の第１実施形態に係る冷媒回路であり冷却運転時を示した概略構成図である。It is the refrigerant circuit which concerns on 1st Embodiment of this disclosure, and is the schematic block diagram which showed the time of cooling operation. 本開示の第２実施形態に係る冷媒回路であり加熱運転時を示した概略構成図である。FIG. 5 is a schematic configuration diagram showing a refrigerant circuit according to a second embodiment of the present disclosure and during a heating operation. 本開示の第２実施形態に係る冷媒回路であり冷却運転時を示した概略構成図である。FIG. 5 is a schematic configuration diagram showing a cooling operation of the refrigerant circuit according to the second embodiment of the present disclosure. 本開示の第３実施形態に係る冷媒回路のｐ－ｈ線図を示したグラフである。It is a graph which showed the ph diagram of the refrigerant circuit which concerns on 3rd Embodiment of this disclosure. 本開示の第３実施形態の変形例を示した冷媒回路を示した概略構成図である。It is a schematic block diagram which showed the refrigerant circuit which showed the modification of the 3rd Embodiment of this disclosure.
　以下に、本開示に係る各実施形態について、図面を参照して説明する。 Hereinafter, each embodiment of the present disclosure will be described with reference to the drawings.
［第１実施形態］
　以下、本開示の第１実施形態について、図１及び図２を用いて説明する。
　図１及び図２には、本実施形態のチラー（熱源機）１の冷媒回路構成が示されている。チラー１は、圧縮機３の吐出側に設けた四方弁（切換弁）４を切り替えることによって、加熱運転と冷却運転とを行うことができる。加熱運転は、水熱交換器（熱媒体熱交換器）５にて水（熱媒体）を加熱する運転であり、冷却運転は水熱交換器５にて水を冷却する運転である。図１には加熱運転を行う場合の冷媒回路が示されており、図２には冷却運転を行う場合の冷媒回路が示されている。 [First Embodiment]
Hereinafter, the first embodiment of the present disclosure will be described with reference to FIGS. 1 and 2.
1 and 2 show a refrigerant circuit configuration of the chiller (heat source machine) 1 of the present embodiment. The chiller 1 can perform a heating operation and a cooling operation by switching the four-way valve (switching valve) 4 provided on the discharge side of the compressor 3. The heating operation is an operation of heating water (heat medium) with a water heat exchanger (heat medium heat exchanger) 5, and a cooling operation is an operation of cooling water with a water heat exchanger 5. FIG. 1 shows a refrigerant circuit in the case of performing a heating operation, and FIG. 2 shows a refrigerant circuit in the case of performing a cooling operation.
　チラー１は、冷媒として、例えば、Ｒ３２が用いられる。Ｒ３２は、低沸点冷媒とされ、地球温暖化係数（ＧＷＰ）が低い冷媒とされている。Ｒ３２に代えて他の冷媒を用いることとしても良い。 For the chiller 1, for example, R32 is used as the refrigerant. R32 is a low boiling point refrigerant and has a low global warming potential (GWP). Another refrigerant may be used instead of R32.
　チラー１は、冷媒を圧縮する圧縮機３と、四方弁４と、水熱交換器５と、第１膨張弁６と、レシーバ７と、第２膨張弁８と、空気熱交換器９と、アキュムレータ１０と、を備えている。これら圧縮機３、四方弁４、水熱交換器５、第１膨張弁６、レシーバ７、第２膨張弁８、空気熱交換器９及びアキュムレータ１０を冷媒配管によって接続することで冷凍サイクルを行う冷媒回路が構成される。 The chiller 1 includes a compressor 3 for compressing the refrigerant, a four-way valve 4, a water heat exchanger 5, a first expansion valve 6, a receiver 7, a second expansion valve 8, an air heat exchanger 9, and the like. It includes an accumulator 10. A refrigeration cycle is performed by connecting the compressor 3, the four-way valve 4, the water heat exchanger 5, the first expansion valve 6, the receiver 7, the second expansion valve 8, the air heat exchanger 9, and the accumulator 10 by a refrigerant pipe. A refrigerant circuit is configured.
　圧縮機３は、例えばスクロール圧縮機やロータリ圧縮機とされており、圧縮機３のハウジング３ａ内にスクロール圧縮機構やロータリ圧縮機構などの圧縮機構３ｂが設けられている。圧縮機構３ｂは、図示しない電動モータによって駆動される。電動モータは、インバータ装置を備えており、図示しない制御部からの指令によって回転数が任意に変更されるようになっている。 The compressor 3 is, for example, a scroll compressor or a rotary compressor, and a compression mechanism 3b such as a scroll compression mechanism or a rotary compression mechanism is provided in the housing 3a of the compressor 3. The compression mechanism 3b is driven by an electric motor (not shown). The electric motor includes an inverter device, and the rotation speed is arbitrarily changed by a command from a control unit (not shown).
　圧縮機３の吐出側には、冷媒の吐出温度を計測する吐出温度センサ１４が設けられている。吐出温度センサ１４の出力は、制御部へ送信される。 A discharge temperature sensor 14 for measuring the discharge temperature of the refrigerant is provided on the discharge side of the compressor 3. The output of the discharge temperature sensor 14 is transmitted to the control unit.
　四方弁４は、加熱運転時には圧縮機３から吐出された冷媒が水熱交換器５へ導かれるように切り換えられ（図１）、冷却運転時には圧縮機３から吐出された冷媒が空気熱交換器９へ導かれるように切り換えられる（図２）。四方弁４の制御は、図示しない制御部によって行われる。 The four-way valve 4 is switched so that the refrigerant discharged from the compressor 3 is guided to the water heat exchanger 5 during the heating operation (FIG. 1), and the refrigerant discharged from the compressor 3 is guided to the air heat exchanger during the cooling operation. It is switched to be guided to 9 (Fig. 2). The control of the four-way valve 4 is performed by a control unit (not shown).
　水熱交換器５は、加熱運転時には凝縮器として動作し（図１）、冷却運転時には蒸発器として動作する（図２）。水熱交換器５には、外部負荷との間で水を循環させる水配管１６が接続されている。水熱交換器５にて水配管１６から導かれた水と冷媒とが熱交換される。 The water heat exchanger 5 operates as a condenser during the heating operation (FIG. 1) and as an evaporator during the cooling operation (FIG. 2). A water pipe 16 for circulating water with an external load is connected to the water heat exchanger 5. The water heat exchanger 5 exchanges heat between the water guided from the water pipe 16 and the refrigerant.
　第１膨張弁６は、図１のように凝縮器として動作する場合の水熱交換器５にて凝縮液化された冷媒を膨張させる。第１膨張弁６の開度は、制御部によって制御される。 The first expansion valve 6 expands the refrigerant liquefied by the water heat exchanger 5 when operating as a condenser as shown in FIG. The opening degree of the first expansion valve 6 is controlled by the control unit.
　第２膨張弁８は、図２のように凝縮器として動作する場合の空気熱交換器９にて凝縮液化された冷媒を膨張させる。第２膨張弁８の開度は、制御部によって制御される。 The second expansion valve 8 expands the refrigerant liquefied by the air heat exchanger 9 when operating as a condenser as shown in FIG. The opening degree of the second expansion valve 8 is controlled by the control unit.
　レシーバ７は、第１膨張弁６と第２膨張弁８との間に設けられ、第１膨張弁６又は第２膨張弁８で膨張された冷媒の一部を一時的に貯留する容器である。レシーバ７の容量（大きさ）は、冷媒回路を循環する冷媒量に応じて決定される。 The receiver 7 is a container provided between the first expansion valve 6 and the second expansion valve 8 and temporarily stores a part of the refrigerant expanded by the first expansion valve 6 or the second expansion valve 8. .. The capacity (magnitude) of the receiver 7 is determined according to the amount of refrigerant circulating in the refrigerant circuit.
　空気熱交換器９は、加熱運転時には蒸発器として動作し（図１）、冷却運転時には凝縮器として動作する（図２）。空気熱交換器９にて冷媒と空気とが熱交換される。空気熱交換器９に対して、ファン１２から空気が送られるようになっている。 The air heat exchanger 9 operates as an evaporator during the heating operation (FIG. 1) and as a condenser during the cooling operation (FIG. 2). The air heat exchanger 9 exchanges heat between the refrigerant and air. Air is sent from the fan 12 to the air heat exchanger 9.
　アキュムレータ１０は、圧縮機３の上流側すなわち冷媒吸入側に設けられ、空気熱交換器９又は水熱交換器５にて蒸発させられた冷媒を一時的に貯留する容器である。 The accumulator 10 is a container provided on the upstream side of the compressor 3, that is, the refrigerant suction side, and temporarily stores the refrigerant evaporated by the air heat exchanger 9 or the water heat exchanger 5.
　水熱交換器５と第１膨張弁６との間には、液バイパス配管２０の上流端が接続されている。液バイパス配管２０の下流端は、圧縮機３の圧縮機構３ｂの吸込側に接続されている。液バイパス弁２２を介して、加熱運転時に凝縮器として動作する水熱交換器５から導かれた液冷媒の一部が圧縮機構３ｂへ導かれる。すなわち、液バイパス弁２２は、第１膨張弁６，レシーバ７、第２膨張弁８、空気熱交換器９及びアキュムレータ１０をバイパスする。 The upstream end of the liquid bypass pipe 20 is connected between the water heat exchanger 5 and the first expansion valve 6. The downstream end of the liquid bypass pipe 20 is connected to the suction side of the compression mechanism 3b of the compressor 3. Through the liquid bypass valve 22, a part of the liquid refrigerant guided from the water heat exchanger 5 that operates as a condenser during the heating operation is guided to the compression mechanism 3b. That is, the liquid bypass valve 22 bypasses the first expansion valve 6, the receiver 7, the second expansion valve 8, the air heat exchanger 9, and the accumulator 10.
　液バイパス配管２０の中途位置には、液バイパス弁２２が設けられている。液バイパス弁２２は、電磁弁などの開閉弁とされており、その開閉動作は制御部によって行われる。 A liquid bypass valve 22 is provided in the middle of the liquid bypass pipe 20. The liquid bypass valve 22 is an on-off valve such as a solenoid valve, and the opening / closing operation is performed by the control unit.
　チラー１の筐体内またはチラー１の近傍には外気温センサ１８が設けられている。外気温センサによって、外気温度が計測される。外気温センサ１８によって計測される外気温度が、ファン１２によって空気熱交換器９に導かれる空気温度とされる。外気温センサ１８の出力は制御部に送信される。 An outside air temperature sensor 18 is provided in the housing of the chiller 1 or in the vicinity of the chiller 1. The outside air temperature is measured by the outside air temperature sensor. The outside air temperature measured by the outside air temperature sensor 18 is taken as the air temperature guided to the air heat exchanger 9 by the fan 12. The output of the outside air temperature sensor 18 is transmitted to the control unit.
　制御部は、例えば、ＣＰＵ（Central　Processing　Unit）、ＲＡＭ（Random　Access　Memory）、ＲＯＭ（Read　Only　Memory）、及びコンピュータ読み取り可能な記憶媒体等から構成されている。そして、各種機能を実現するための一連の処理は、一例として、プログラムの形式で記憶媒体等に記憶されており、このプログラムをＣＰＵがＲＡＭ等に読み出して、情報の加工・演算処理を実行することにより、各種機能が実現される。プログラムは、ＲＯＭやその他の記憶媒体に予めインストールしておく形態や、コンピュータ読み取り可能な記憶媒体に記憶された状態で提供される形態、有線又は無線による通信手段を介して配信される形態等が適用されてもよい。コンピュータ読み取り可能な記憶媒体とは、磁気ディスク、光磁気ディスク、ＣＤ－ＲＯＭ、ＤＶＤ－ＲＯＭ、半導体メモリ等である。 The control unit is composed of, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a computer-readable storage medium, and the like. As an example, a series of processes for realizing various functions are stored in a storage medium or the like in the form of a program, and the CPU reads this program into a RAM or the like to execute information processing / arithmetic processing. As a result, various functions are realized. The program may be installed in a ROM or other storage medium in advance, provided in a state of being stored in a computer-readable storage medium, or distributed via a wired or wireless communication means. May be applied. The computer-readable storage medium is a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like.
　次に、上記構成とされたチラー１の動作について説明する。
＜加熱運転：図１＞
　水熱交換器５にて水を加熱する場合には、図１に示すように四方弁４を切り換えて、圧縮機３から吐出された高圧ガス冷媒が水熱交換器５に導かれる。水熱交換器５では、水配管１６から導かれた水と熱交換することによって冷媒が凝縮する。冷媒が凝縮する際の潜熱によって水が加熱される。加熱された水は、水配管１６を介して外部負荷へと導かれる。 Next, the operation of the chiller 1 having the above configuration will be described.
<Heating operation: Fig. 1>
When the water is heated by the water heat exchanger 5, the four-way valve 4 is switched as shown in FIG. 1, and the high-pressure gas refrigerant discharged from the compressor 3 is guided to the water heat exchanger 5. In the water heat exchanger 5, the refrigerant is condensed by exchanging heat with the water guided from the water pipe 16. Water is heated by the latent heat of condensation of the refrigerant. The heated water is guided to an external load via the water pipe 16.
　水熱交換器５にて凝縮した液冷媒は、第１膨張弁６へと導かれて膨張させられる。膨張後の冷媒は、レシーバ７へと導かれ、一部の冷媒が余剰冷媒としてレシーバ７内で貯留される。レシーバ７から取り出された冷媒は、第２膨張弁８を介して空気熱交換器９へと導かれる。 The liquid refrigerant condensed in the water heat exchanger 5 is guided to the first expansion valve 6 and expanded. The expanded refrigerant is guided to the receiver 7, and a part of the refrigerant is stored in the receiver 7 as a surplus refrigerant. The refrigerant taken out from the receiver 7 is guided to the air heat exchanger 9 via the second expansion valve 8.
　空気熱交換器９では、ファン１２によって導かれた空気と熱交換することによって冷媒が蒸発する。空気熱交換器９で蒸発した冷媒は四方弁４を通りアキュムレータ１０へと導かれる。アキュムレータ１０から導かれたガス冷媒は、圧縮機３の吸込側へと導かれて再び圧縮機構３ｂによって圧縮される。 In the air heat exchanger 9, the refrigerant evaporates by exchanging heat with the air guided by the fan 12. The refrigerant evaporated in the air heat exchanger 9 is guided to the accumulator 10 through the four-way valve 4. The gas refrigerant guided from the accumulator 10 is guided to the suction side of the compressor 3 and is compressed again by the compression mechanism 3b.
　制御部は、外気温センサ１８にて計測した外気温が所定値以下（例えば０℃以下又は－５℃以下）の低外気温となった場合に、液バイパス配管２０に設けた液バイパス弁２２を閉から開へと制御する。これにより、水熱交換器５から導かれた液冷媒の一部が液バイパス配管２０を介して圧縮機３の圧縮機構３ｂの吸入側に導かれる。このように液冷媒を圧縮機構３ｂの吸入側に供給することによって、圧縮機３から吐出される冷媒の吐出温度が低減される。 The control unit has a liquid bypass valve 22 provided in the liquid bypass pipe 20 when the outside air temperature measured by the outside air temperature sensor 18 becomes a low outside air temperature of a predetermined value or less (for example, 0 ° C. or less or -5 ° C. or less). Is controlled from closed to open. As a result, a part of the liquid refrigerant guided from the water heat exchanger 5 is guided to the suction side of the compression mechanism 3b of the compressor 3 via the liquid bypass pipe 20. By supplying the liquid refrigerant to the suction side of the compression mechanism 3b in this way, the discharge temperature of the refrigerant discharged from the compressor 3 is reduced.
　液バイパス弁２２の開閉の制御は、外気温センサ１８で計測された温度と共に、又は、外気温センサ１８で計測された温度に代えて、吐出温度センサ１４で計測された温度や、圧縮機３の圧力比を用いても良い。例えば、水熱交換器５にて加熱される水温が５０℃に対応する温度に吐出温度センサ１４の計測値がなったとき、及び／又は、圧縮機３の圧力比が４．５以上となったときに、液バイパス弁２２を閉から開へと制御する。 The control of opening and closing of the liquid bypass valve 22 is performed together with the temperature measured by the outside air temperature sensor 18, or instead of the temperature measured by the outside air temperature sensor 18, the temperature measured by the discharge temperature sensor 14 or the compressor 3 The pressure ratio of may be used. For example, when the measured value of the discharge temperature sensor 14 reaches a temperature corresponding to 50 ° C. of the water temperature heated by the water heat exchanger 5, and / or the pressure ratio of the compressor 3 becomes 4.5 or more. At that time, the liquid bypass valve 22 is controlled from closed to open.
＜冷却運転：図２＞
　水熱交換器５にて水を冷却する場合には、図２に示すように四方弁４を切り換えて、圧縮機３から吐出された高圧ガス冷媒が空気熱交換器９に導かれる。空気熱交換器９では、ファン１２によって導かれた空気と熱交換することによって冷媒が凝縮する。 <Cooling operation: Fig. 2>
When the water is cooled by the water heat exchanger 5, the four-way valve 4 is switched as shown in FIG. 2, and the high-pressure gas refrigerant discharged from the compressor 3 is guided to the air heat exchanger 9. In the air heat exchanger 9, the refrigerant is condensed by exchanging heat with the air guided by the fan 12.
　空気熱交換器９にて凝縮した液冷媒は、第２膨張弁８へと導かれて膨張させられる。膨張後の冷媒は、レシーバ７へと導かれ、一部の冷媒がレシーバ７内で貯留される。レシーバ７から取り出された冷媒は、第１膨張弁６を介して水熱交換器５へと導かれる。 The liquid refrigerant condensed in the air heat exchanger 9 is guided to the second expansion valve 8 and expanded. The expanded refrigerant is guided to the receiver 7, and a part of the refrigerant is stored in the receiver 7. The refrigerant taken out from the receiver 7 is guided to the water heat exchanger 5 via the first expansion valve 6.
　水熱交換器５では、水配管１６から導かれた水と熱交換することによって冷媒が蒸発する。冷媒の蒸発潜熱によって冷却された水は、水配管１６を介して外部負荷へと導かれる。 In the water heat exchanger 5, the refrigerant evaporates by exchanging heat with the water guided from the water pipe 16. The water cooled by the latent heat of vaporization of the refrigerant is guided to an external load via the water pipe 16.
　水熱交換器５で蒸発した冷媒は四方弁４を通りアキュムレータ１０へと導かれる。アキュムレータ１０から導かれたガス冷媒は、圧縮機３の吸込側へと導かれて再び圧縮機構３ｂによって圧縮される。 The refrigerant evaporated in the water heat exchanger 5 is guided to the accumulator 10 through the four-way valve 4. The gas refrigerant guided from the accumulator 10 is guided to the suction side of the compressor 3 and is compressed again by the compression mechanism 3b.
　制御部は、冷却運転の時は、液バイパス弁２２を閉としたままとする。すなわち、冷却運転の時は液バイパス配管２０を使用しない。 The control unit keeps the liquid bypass valve 22 closed during the cooling operation. That is, the liquid bypass pipe 20 is not used during the cooling operation.
　本実施形態によれば、以下の作用効果を奏する。
　液バイパス配管２０によって液冷媒が圧縮機構３ｂの吸入側に導かれることによって、圧縮機３から吐出される冷媒温度を低下させることができる。これにより、高圧力比での運転が可能となり、チラー１の使用範囲を拡大することができる。
　液バイパス配管２０には液冷媒が流れるので、口径（管内径）をガス冷媒が混合された二相冷媒よりも小さくすることができる。これにより、コストを低減できるとともに配管の取り回しが容易となる。 According to this embodiment, the following effects are exhibited.
By guiding the liquid refrigerant to the suction side of the compression mechanism 3b by the liquid bypass pipe 20, the temperature of the refrigerant discharged from the compressor 3 can be lowered. This enables operation at a high pressure ratio and expands the range of use of the chiller 1.
Since the liquid refrigerant flows through the liquid bypass pipe 20, the diameter (inner diameter of the pipe) can be made smaller than that of the two-phase refrigerant mixed with the gas refrigerant. As a result, the cost can be reduced and the piping can be easily routed.
　液バイパス配管２０の上流端は、水熱交換器５と第１膨張弁６との間に設けられている。これにより、膨張前の冷媒を液冷媒として確実に圧縮機３へと導くことができる。
　液バイパス配管２０によって液冷媒の一部が圧縮機３へとバイパスされるので、第１膨張弁６と第２膨張弁８との間に設けられたレシーバ７の容量（大きさ）を小さくすることができる。これにより、省スペース化を図ることができるとともにコストを低減できる。 The upstream end of the liquid bypass pipe 20 is provided between the water heat exchanger 5 and the first expansion valve 6. As a result, the refrigerant before expansion can be reliably guided to the compressor 3 as a liquid refrigerant.
Since a part of the liquid refrigerant is bypassed to the compressor 3 by the liquid bypass pipe 20, the capacity (size) of the receiver 7 provided between the first expansion valve 6 and the second expansion valve 8 is reduced. be able to. As a result, space can be saved and costs can be reduced.
　加熱運転でかつ外気温度が所定値以下とされた低外気温時には、高圧力比（例えば４．５以上）となって圧縮機３から吐出される冷媒温度が高温となるおそれがある。そこで、このような条件の場合には液バイパス弁２２を開として液冷媒を圧縮機構３ｂの吸入側に導くようにした。 In the heating operation and at a low outside air temperature where the outside air temperature is set to a predetermined value or less, a high pressure ratio (for example, 4.5 or more) may occur and the temperature of the refrigerant discharged from the compressor 3 may become high. Therefore, under such conditions, the liquid bypass valve 22 is opened to guide the liquid refrigerant to the suction side of the compression mechanism 3b.
［第２実施形態］
　次に、本開示の第２実施形態について、図３及び図４を用いて説明する。本実施形態は、第１実施形態と基本的構成は同様であるので、以下では、第１実施形態に対して追加した構成についてのみ説明する。 [Second Embodiment]
Next, the second embodiment of the present disclosure will be described with reference to FIGS. 3 and 4. Since the basic configuration of this embodiment is the same as that of the first embodiment, only the configuration added to the first embodiment will be described below.
　図３及び図４に示すように、液バイパス配管２０の上流端と第１膨張弁６との間から分岐し、かつ、第２膨張弁８と空気熱交換器９との間から分岐する並列冷媒配管３０が設けられている。並列冷媒配管３０は、第１膨張弁６、レシーバ７及び第２膨張弁８に対して並列に設けられている。これにより、並列冷媒配管３０は、第１膨張弁６、レシーバ７及び第２膨張弁８をバイパスして水熱交換器５と空気熱交換器９とを接続している。 As shown in FIGS. 3 and 4, parallel branches that branch from the upstream end of the liquid bypass pipe 20 and the first expansion valve 6 and branch from between the second expansion valve 8 and the air heat exchanger 9. A refrigerant pipe 30 is provided. The parallel refrigerant pipe 30 is provided in parallel with the first expansion valve 6, the receiver 7, and the second expansion valve 8. As a result, the parallel refrigerant pipe 30 bypasses the first expansion valve 6, the receiver 7, and the second expansion valve 8 to connect the water heat exchanger 5 and the air heat exchanger 9.
　並列冷媒配管３０には、第３膨張弁３２が設けられている。第３膨張弁の開度は、制御部によって制御される。 The parallel refrigerant pipe 30 is provided with a third expansion valve 32. The opening degree of the third expansion valve is controlled by the control unit.
　次に、上記構成とされたチラー１の動作について説明する。
＜加熱運転：図３＞
　加熱運転時には、第３膨張弁３２は制御部の指令によって全閉とされている。したがって、加熱運転時には並列冷媒配管３０を用いないので、加熱運転時は第１実施形態の図１と同様の動作を行う。低外気温時には、第１実施形態と同様に液バイパス弁２２を開として液冷媒による冷媒吐出温度の低減を行う。 Next, the operation of the chiller 1 having the above configuration will be described.
<Heating operation: Fig. 3>
During the heating operation, the third expansion valve 32 is fully closed by a command from the control unit. Therefore, since the parallel refrigerant pipe 30 is not used during the heating operation, the same operation as in FIG. 1 of the first embodiment is performed during the heating operation. When the outside air temperature is low, the liquid bypass valve 22 is opened to reduce the refrigerant discharge temperature by the liquid refrigerant as in the first embodiment.
＜冷却運転：図４＞
　冷却運転時には、制御部の指令によって第１膨張弁６及び第２膨張弁８を全閉とし、レシーバ７に冷媒を流さないようにする。液バイパス弁２２も全閉とし、液バイパス配管２０を用いない。したがって、空気熱交換器９から導かれた液冷媒の全ては、並列冷媒配管３０へと導かれ、制御部によって開度制御された第３膨張弁３２によって膨張させられる。第３膨張弁３２によって膨張させられた冷媒は水熱交換器５へ導かれる。これ以降の動作は第１実施形態の図２と同様なので省略する。 <Cooling operation: Fig. 4>
During the cooling operation, the first expansion valve 6 and the second expansion valve 8 are fully closed by the command of the control unit so that the refrigerant does not flow to the receiver 7. The liquid bypass valve 22 is also fully closed, and the liquid bypass pipe 20 is not used. Therefore, all of the liquid refrigerant guided from the air heat exchanger 9 is guided to the parallel refrigerant pipe 30, and is expanded by the third expansion valve 32 whose opening degree is controlled by the control unit. The refrigerant expanded by the third expansion valve 32 is guided to the water heat exchanger 5. Since the subsequent operations are the same as those in FIG. 2 of the first embodiment, they will be omitted.
　本実施形態のチラー１は、以下の作用効果を奏する。
　第１膨張弁６、レシーバ７、第２膨張弁８に対して並列に並列冷媒配管３０を設けることとした。そして、加熱運転時には第３膨張弁３２を閉として第１膨張弁６側に冷媒が流れるようにした。これにより、加熱運転時には余剰の冷媒をレシーバ７で貯留することができる。 The chiller 1 of the present embodiment has the following effects.
It was decided to provide the parallel refrigerant pipe 30 in parallel with the first expansion valve 6, the receiver 7, and the second expansion valve 8. Then, during the heating operation, the third expansion valve 32 is closed so that the refrigerant flows to the first expansion valve 6 side. As a result, the excess refrigerant can be stored in the receiver 7 during the heating operation.
　低外気温時には液バイパス配管２０を用いて液冷媒の一部を圧縮機３へ導いてレシーバ７をバイパスさせることができる。これにより、レシーバ７の容量を低減できる。 When the outside temperature is low, a part of the liquid refrigerant can be guided to the compressor 3 to bypass the receiver 7 by using the liquid bypass pipe 20. As a result, the capacity of the receiver 7 can be reduced.
　一方、冷却運転時には第３膨張弁３２を開として並列冷媒配管３０に冷媒を流し第２膨張弁８側には冷媒を流さないようにした。これにより、冷却運転時にはレシーバ７に冷媒を貯留することなく必要な冷媒を過不足なく用いることができる。 On the other hand, during the cooling operation, the third expansion valve 32 was opened so that the refrigerant flowed through the parallel refrigerant pipe 30 and the refrigerant did not flow on the second expansion valve 8 side. As a result, the necessary refrigerant can be used in just proportion without storing the refrigerant in the receiver 7 during the cooling operation.
　以上により、加熱運転と冷却運転を行うチラー１であっても必要十分な冷媒量を選定することができ、使用する冷媒量を低減できる。 From the above, it is possible to select a necessary and sufficient amount of refrigerant even in the chiller 1 that performs heating operation and cooling operation, and it is possible to reduce the amount of refrigerant used.
　冷却運転時に並列冷媒配管３０を用いる場合は第３膨張弁３２で冷媒を膨張させることとなり、１つの膨張弁で膨張させることができる。したがって、並列冷媒配管３０にて第３膨張弁３２のみを用いれば、第１膨張弁６及び第２膨張弁８の２つで膨張させる場合に比べて、高低差圧（水熱交換器５と空気熱交換器９の冷媒差圧）が比較的小さい場合に、膨張弁の口径不足となることを回避できる。 When the parallel refrigerant pipe 30 is used during the cooling operation, the refrigerant is expanded by the third expansion valve 32, and can be expanded by one expansion valve. Therefore, if only the third expansion valve 32 is used in the parallel refrigerant pipe 30, the high and low differential pressure (with the water heat exchanger 5) is compared with the case of expanding with the first expansion valve 6 and the second expansion valve 8. When the refrigerant differential pressure of the air heat exchanger 9) is relatively small, it is possible to avoid an insufficient diameter of the expansion valve.
［第３実施形態］
　次に、本開示の第３実施形態について説明する。
　本実施形態のチラー１は、図１乃至図４に示した第１実施形態及び第２実施形態の構成を用いることができるので、その説明を省略する。 [Third Embodiment]
Next, a third embodiment of the present disclosure will be described.
Since the chiller 1 of the present embodiment can use the configurations of the first embodiment and the second embodiment shown in FIGS. 1 to 4, the description thereof will be omitted.
　本実施形態の制御部は、図１及び図３に示した加熱運転時に、圧縮機３から吐出される冷媒の温度が所定値以下となるように第１膨張弁６の開度を制御する。具体的には、吐出温度センサ１４の計測値が所定値を超えた場合に、第１膨張弁６の開度を閉方向に絞る。ここで、所定値とは、例えば、水熱交換器５にて加熱される水温が５０℃の場合に対応する吐出温度センサ１４での計測温度、または該計測温度よりも数℃低い温度を意味する。 The control unit of the present embodiment controls the opening degree of the first expansion valve 6 so that the temperature of the refrigerant discharged from the compressor 3 becomes a predetermined value or less during the heating operation shown in FIGS. 1 and 3. Specifically, when the measured value of the discharge temperature sensor 14 exceeds a predetermined value, the opening degree of the first expansion valve 6 is narrowed down in the closing direction. Here, the predetermined value means, for example, the temperature measured by the discharge temperature sensor 14 corresponding to the case where the water temperature heated by the water heat exchanger 5 is 50 ° C., or a temperature several ° C. lower than the measured temperature. do.
　第１膨張弁６の開度を絞ることで、冷媒循環量を低減して水熱交換器５での凝縮能力を増大させて冷媒の液相割合を多くし、液バイパス配管２０を通り圧縮機３へと導く液冷媒量を増大させる。そして、圧縮機３の吸入側に導かれる液冷媒量が上昇することによって、吐出ガス温度が低下する。 By narrowing the opening degree of the first expansion valve 6, the amount of refrigerant circulation is reduced, the condensation capacity of the water heat exchanger 5 is increased, the liquid phase ratio of the refrigerant is increased, and the compressor passes through the liquid bypass pipe 20. Increase the amount of liquid refrigerant leading to 3. Then, the amount of the liquid refrigerant guided to the suction side of the compressor 3 increases, so that the discharge gas temperature decreases.
　上記の過程が図５のｐ（圧力）－ｈ（比エンタルピ）線図に示されている。同図に示されているように、第１膨張弁６を絞ることによって、比エンタルピがＨＬ２のＣ２点から比エンタルピがＨＬ１のＣ１点に移動し、過冷却度が増大する。過冷却度が増大して液冷媒量が増大した冷媒（Ｌ１点）は、液バイパス配管２０を介して圧縮機３の吸込位置であるＡ点（比エンタルピＨＡ）に至り、第１膨張弁６でＤ１点まで膨張して空気熱交換器９で蒸発した冷媒と圧縮機構３ｂの吸入側で合流しＳ１点（比エンタルピＨＳ１）となる。そして、圧縮機構３ｂで圧縮された冷媒は、高温高圧となりＢ１点に至る。 The above process is shown in the p (pressure) -h (specific enthalpy) diagram of FIG. As shown in the figure, by throttle the first expansion valve 6, the specific enthalpy moves from the C2 point of HL2 to the C1 point of HL1, and the degree of supercooling increases. The refrigerant (point L1) in which the degree of supercooling has increased and the amount of liquid refrigerant has increased reaches point A (specific enthalpy HA), which is the suction position of the compressor 3, via the liquid bypass pipe 20, and the first expansion valve 6 The refrigerant expanded to the D1 point and evaporated in the air heat exchanger 9 merges with the suction side of the compression mechanism 3b to become the S1 point (specific enthalpy HS1). Then, the refrigerant compressed by the compression mechanism 3b becomes high temperature and high pressure and reaches the B1 point.
　一方、第１膨張弁６の開度を絞る前の冷媒はＣ２点からＤ２点及びＬ２点を介してＳ２点（比エンタルピＨＳ２）で合流する。そして、圧縮機構３ｂで圧縮された冷媒は、Ｂ２点に至る。 On the other hand, the refrigerant before narrowing the opening degree of the first expansion valve 6 merges from the C2 point through the D2 point and the L2 point at the S2 point (specific enthalpy HS2). Then, the refrigerant compressed by the compression mechanism 3b reaches the point B2.
　Ｂ１点とＢ２点とを比較すれば明らかなように、第１膨張弁６の開度を絞ったＢ１点の方がＢ２点よりも温度が低く、吐出温度が低くなることが分かる。
　以上の通り、第１膨張弁６の開度を絞ることによって過冷却度を増大させることで、液バイパス弁２２の開度を制御することなく吐出温度を低下させることができる。 As is clear from a comparison between the B1 point and the B2 point, it can be seen that the temperature at the B1 point where the opening degree of the first expansion valve 6 is narrowed is lower than that at the B2 point, and the discharge temperature is lower.
As described above, by increasing the degree of supercooling by reducing the opening degree of the first expansion valve 6, the discharge temperature can be lowered without controlling the opening degree of the liquid bypass valve 22.
　本実施形態の作用効果は以下の通りである。
　第１膨張弁６の開度を制御することによって圧縮機３から吐出される冷媒の温度を所定値以下に制御するようにした。これにより、液バイパス弁２２として弁開度が可変とされた調整弁ではなく弁の開閉のみとされた開閉弁（電磁弁）を採用することができ、コストを低減できる。また液バイパス弁２２の開度調整が不要なので制御を簡素化することができる。 The effects of this embodiment are as follows.
By controlling the opening degree of the first expansion valve 6, the temperature of the refrigerant discharged from the compressor 3 is controlled to a predetermined value or less. As a result, it is possible to adopt an on-off valve (solenoid valve) that only opens and closes the valve instead of the adjusting valve that has a variable valve opening degree as the liquid bypass valve 22, and the cost can be reduced. Further, since it is not necessary to adjust the opening degree of the liquid bypass valve 22, the control can be simplified.
　本実施形態は、図６のように変形することができる。
　図６は図１に対応し、液バイパス配管２０の上流端の位置が異なる。それ以外の構成は図１と同様である。本変形例は、液バイパス配管２０の上流端が第１膨張弁６とレシーバ７との間に接続されている。このような構成であっても、上述した本実施形態のように第１膨張弁６による吐出冷媒温度の制御が可能である。 This embodiment can be modified as shown in FIG.
FIG. 6 corresponds to FIG. 1, and the position of the upstream end of the liquid bypass pipe 20 is different. Other than that, the configuration is the same as in FIG. In this modification, the upstream end of the liquid bypass pipe 20 is connected between the first expansion valve 6 and the receiver 7. Even with such a configuration, it is possible to control the discharge refrigerant temperature by the first expansion valve 6 as in the present embodiment described above.
　以上説明した各実施形態に記載の熱源機及びその制御方法は、例えば以下のように把握される。 The heat source machine and its control method described in each of the above-described embodiments are grasped as follows, for example.
　本開示の一態様に係る熱源機は、（１）は、冷媒を圧縮する圧縮機（３）と、冷媒と熱媒体とを熱交換する熱媒体熱交換器（５）と、冷媒を膨張させる膨張弁（６）と、冷媒と空気とを熱交換する空気熱交換器（９）と、前記熱媒体熱交換器と前記膨張弁との間に上流端が接続されて液冷媒を前記圧縮機の吸入側に導く液バイパス配管（２０）と、を備えている。 In the heat source machine according to one aspect of the present disclosure, (1) includes a compressor (3) for compressing the refrigerant, a heat medium heat exchanger (5) for heat exchange between the refrigerant and the heat medium, and an expansion of the refrigerant. An upstream end is connected between the expansion valve (6), an air heat exchanger (9) that exchanges heat between the refrigerant and air, and the heat medium heat exchanger and the expansion valve, and the liquid refrigerant is used in the compressor. It is provided with a liquid bypass pipe (20) leading to the suction side of the.
　液バイパス配管によって液冷媒が圧縮機の吸入側に導かれることによって、圧縮機から吐出される冷媒温度を低下させることができる。これにより、高圧力比での運転が可能となり、熱源機の使用範囲を拡大することができる。
　液バイパス配管には液冷媒が流れるので、口径（管内径）をガス冷媒が混合された二相冷媒よりも小さくすることができる。これにより、コストを低減できるとともに配管の取り回しが容易となる。 By guiding the liquid refrigerant to the suction side of the compressor by the liquid bypass pipe, the temperature of the refrigerant discharged from the compressor can be lowered. This enables operation at a high pressure ratio and expands the range of use of the heat source machine.
Since the liquid refrigerant flows through the liquid bypass pipe, the diameter (inner diameter of the pipe) can be made smaller than that of the two-phase refrigerant mixed with the gas refrigerant. As a result, the cost can be reduced and the piping can be easily routed.
　さらに、本開示の一態様に係る熱源機では、前記膨張弁は、前記熱媒体熱交換器側に設けられた第１膨張弁と、前記空気熱交換器側に設けられた第２膨張弁（８）とを備え、前記液バイパス配管の前記上流端は、前記熱媒体熱交換器と前記第１膨張弁との間に接続され、前記第１膨張弁と前記第２膨張弁との間に、冷媒を貯留するレシーバ（７）が設けられている。 Further, in the heat source machine according to one aspect of the present disclosure, the expansion valve includes a first expansion valve provided on the heat medium heat exchanger side and a second expansion valve provided on the air heat exchanger side. 8), the upstream end of the liquid bypass pipe is connected between the heat medium heat exchanger and the first expansion valve, and between the first expansion valve and the second expansion valve. , A receiver (7) for storing the refrigerant is provided.
　液バイパス配管の上流端は、熱媒体熱交換器と第１膨張弁との間に設けられている。これにより、膨張前の冷媒を液冷媒として確実に圧縮機へと導くことができる。
　液バイパス配管によって液冷媒の一部が圧縮機へとバイパスされるので、第１膨張弁と第２膨張弁との間に設けられたレシーバの容量を小さくすることができる。これにより、省スペース化を図ることができるとともにコストを低減できる。 The upstream end of the liquid bypass pipe is provided between the heat medium heat exchanger and the first expansion valve. As a result, the refrigerant before expansion can be reliably guided to the compressor as a liquid refrigerant.
Since a part of the liquid refrigerant is bypassed to the compressor by the liquid bypass pipe, the capacity of the receiver provided between the first expansion valve and the second expansion valve can be reduced. As a result, space can be saved and costs can be reduced.
　さらに、本開示の一態様に係る熱源機では、前記熱媒体を加熱する加熱運転時に前記圧縮機から吐出された冷媒を前記熱媒体熱交換器へと導き、前記熱媒体を冷却する冷却運転時に前記圧縮機から吐出された冷媒を前記空気熱交換器へと導く切換弁と、前記液バイパス配管に設けられた液バイパス弁（２２）と、前記加熱運転時で、かつ、前記空気熱交換器の周囲の空気温度が所定値以下とされた場合に、前記液バイパス弁を閉から開へと制御する制御部と、を備えている。 Further, in the heat source machine according to one aspect of the present disclosure, during the cooling operation in which the refrigerant discharged from the compressor is guided to the heat medium heat exchanger during the heating operation for heating the heat medium and the heat medium is cooled. A switching valve that guides the refrigerant discharged from the compressor to the air heat exchanger, a liquid bypass valve (22) provided in the liquid bypass pipe, and the air heat exchanger during the heating operation. It is provided with a control unit for controlling the liquid bypass valve from closed to open when the ambient air temperature is equal to or lower than a predetermined value.
　加熱運転でかつ空気熱交換器の周囲の空気温度が所定値（例えば０℃）以下とされたときには、高圧力比（例えば４．５以上）となって圧縮機から吐出される冷媒温度が高温となるおそれがある。そこで、このような条件の場合には液バイパス弁を開として液冷媒を圧縮機の吸入側に導くようにした。 In the heating operation and when the air temperature around the air heat exchanger is set to a predetermined value (for example, 0 ° C.) or less, the pressure ratio becomes high (for example, 4.5 or more) and the temperature of the refrigerant discharged from the compressor is high. There is a risk of becoming. Therefore, under such conditions, the liquid bypass valve is opened to guide the liquid refrigerant to the suction side of the compressor.
　さらに、本開示の一態様に係る熱源機では、前記熱媒体を加熱する加熱運転時に前記圧縮機から吐出された冷媒を前記熱媒体熱交換器へと導き、前記熱媒体を冷却する冷却運転時に前記圧縮機から吐出された冷媒を前記空気熱交換器へと導く切換弁と、前記第１膨張弁、前記レシーバ、及び前記第２膨張弁に対して並列に設けられ、前記熱媒体熱交換器と前記空気熱交換器とを接続する並列冷媒配管（３０）と、前記並列冷媒配管に設けられた第３膨張弁（３２）と、前記加熱運転時に、前記第３膨張弁を閉とし、前記第１膨張弁側に冷媒を流すように前記第１膨張弁及び／又は前記第２膨張弁の開度を制御し、前記冷却運転時に、前記第３膨張弁を開とし、前記第２膨張弁側に冷媒を流さないように前記第１膨張弁及び／又は前記第２膨張弁の開度を制御する制御部と、を備えている。 Further, in the heat source machine according to one aspect of the present disclosure, during the cooling operation in which the refrigerant discharged from the compressor is guided to the heat medium heat exchanger during the heating operation for heating the heat medium and the heat medium is cooled. A switching valve for guiding the refrigerant discharged from the compressor to the air heat exchanger, and the heat medium heat exchanger provided in parallel with the first expansion valve, the receiver, and the second expansion valve. The parallel refrigerant pipe (30) connecting the air heat exchanger to the air heat exchanger, the third expansion valve (32) provided in the parallel refrigerant pipe, and the third expansion valve closed during the heating operation. The opening degree of the first expansion valve and / or the second expansion valve is controlled so that the refrigerant flows to the first expansion valve side, the third expansion valve is opened during the cooling operation, and the second expansion valve is opened. It is provided with a control unit for controlling the opening degree of the first expansion valve and / or the second expansion valve so that the refrigerant does not flow to the side.
　第１膨張弁、レシーバ、第２膨張弁に対して並列に並列冷媒配管を設けることとした。そして、加熱運転時には第３膨張弁を閉として第１膨張弁側に冷媒が流れるようにした。これにより、加熱運転時には余剰の冷媒をレシーバで貯留することができる。一方、冷却運転時には第３膨張弁を開として並列冷媒配管に冷媒を流し第２膨張弁側には冷媒を流さないようにした。これにより、冷却運転時にはレシーバに冷媒を貯留することなく必要な冷媒を過不足なく用いることができる。
　以上により、加熱運転と冷却運転を行う熱源機であっても必要十分な冷媒量を選定することができ、使用する冷媒量を低減できる。
　冷却運転時に並列冷媒配管を用いる場合は第３膨張弁で冷媒を膨張させることとなり、１つの膨張弁で膨張させることができる。したがって、並列冷媒配管にて第３膨張弁を用いれば、第１膨張弁及び第２膨張弁の２つで膨張させる場合に比べて、高低差圧（熱媒体熱交換器と空気熱交換器の冷媒差圧）が比較的小さい場合に、膨張弁の口径不足となることを回避できる。 It was decided to provide parallel refrigerant pipes in parallel with the first expansion valve, receiver, and second expansion valve. Then, during the heating operation, the third expansion valve was closed so that the refrigerant could flow to the first expansion valve side. As a result, excess refrigerant can be stored in the receiver during the heating operation. On the other hand, during the cooling operation, the third expansion valve was opened so that the refrigerant flowed through the parallel refrigerant pipes and the refrigerant did not flow on the second expansion valve side. As a result, the necessary refrigerant can be used in just proportion without storing the refrigerant in the receiver during the cooling operation.
As described above, it is possible to select a necessary and sufficient amount of refrigerant even in a heat source machine that performs heating operation and cooling operation, and it is possible to reduce the amount of refrigerant used.
When the parallel refrigerant pipe is used during the cooling operation, the refrigerant is expanded by the third expansion valve, and can be expanded by one expansion valve. Therefore, if the third expansion valve is used in the parallel refrigerant pipe, the differential pressure (heat medium heat exchanger and air heat exchanger) is higher and lower than when the third expansion valve is used to expand the first expansion valve and the second expansion valve. When the refrigerant differential pressure) is relatively small, it is possible to avoid an insufficient diameter of the expansion valve.
　さらに、本開示の一態様に係る熱源機では、前記熱媒体を加熱する加熱運転時に前記圧縮機から吐出された冷媒を前記熱媒体熱交換器へと導き、前記熱媒体を冷却する冷却運転時に前記圧縮機から吐出された冷媒を前記空気熱交換器へと導く切換弁と、前記液バイパス配管に設けられ、開閉弁とされた液バイパス弁と、前記加熱運転時に、前記圧縮機から吐出される冷媒の温度が所定値以下となるように、前記第１膨張弁の開度を制御する制御部と、を備えている。 Further, in the heat source machine according to one aspect of the present disclosure, during the cooling operation in which the refrigerant discharged from the compressor is guided to the heat medium heat exchanger during the heating operation for heating the heat medium and the heat medium is cooled. A switching valve that guides the refrigerant discharged from the compressor to the air heat exchanger, a liquid bypass valve provided in the liquid bypass pipe and used as an on-off valve, and a liquid bypass valve that is discharged from the compressor during the heating operation. It is provided with a control unit for controlling the opening degree of the first expansion valve so that the temperature of the refrigerant becomes equal to or lower than a predetermined value.
　第１膨張弁の開度を制御することによって圧縮機から吐出される冷媒の温度を所定値以下に制御するようにした。これにより、液バイパス弁として弁開度が可変とされた調整弁ではなく弁の開閉のみとされた開閉弁を採用することができ、コストを低減できる。また液バイパス弁の開度調整が不要なので制御を簡素化することができる。 By controlling the opening degree of the first expansion valve, the temperature of the refrigerant discharged from the compressor is controlled to a predetermined value or less. As a result, it is possible to adopt an on-off valve that only opens and closes the valve instead of the adjusting valve that has a variable valve opening as the liquid bypass valve, and the cost can be reduced. Further, since it is not necessary to adjust the opening degree of the liquid bypass valve, the control can be simplified.
　本開示の一態様に係る熱源機の制御方法は、冷媒を圧縮する圧縮機と、冷媒と熱媒体とを熱交換する熱媒体熱交換器と、冷媒を膨張させる膨張弁と、冷媒と空気とを熱交換する空気熱交換器と、前記熱媒体熱交換器と前記膨張弁との間に上流端が接続されて液冷媒を前記圧縮機の吸入側に導く液バイパス配管と、前記液バイパス配管に設けられた液バイパス弁と、前記熱媒体を加熱する加熱運転時に前記圧縮機から吐出された冷媒を前記熱媒体熱交換器へと導き、前記熱媒体を冷却する冷却運転時に前記圧縮機から吐出された冷媒を前記空気熱交換器へと導く切換弁と、を備えた熱源機の制御方法であって、前記加熱運転時で、かつ、前記空気熱交換器の周囲の空気温度が所定値以下とされた場合に、前記液バイパス弁を閉から開へと制御する。 The heat source machine control method according to one aspect of the present disclosure includes a compressor that compresses the refrigerant, a heat medium heat exchanger that exchanges heat between the refrigerant and the heat medium, an expansion valve that expands the refrigerant, and the refrigerant and air. A liquid bypass pipe in which an upstream end is connected between the heat medium heat exchanger and the expansion valve to guide the liquid refrigerant to the suction side of the compressor, and the liquid bypass pipe. The liquid bypass valve provided in the above and the refrigerant discharged from the compressor during the heating operation for heating the heat medium are guided to the heat medium heat exchanger, and from the compressor during the cooling operation for cooling the heat medium. It is a control method of a heat source machine provided with a switching valve for guiding the discharged refrigerant to the air heat exchanger, and the air temperature around the air heat exchanger is a predetermined value during the heating operation. In the following cases, the liquid bypass valve is controlled from closed to open.
　本開示の一態様に係る熱源機の制御方法は、冷媒を圧縮する圧縮機と、冷媒と熱媒体とを熱交換する熱媒体熱交換器と、冷媒と空気とを熱交換する空気熱交換器と、前記熱媒体熱交換器側に設けられた第１膨張弁と、前記空気熱交換器側に設けられた第２膨張弁と、前記熱媒体熱交換器と前記第１膨張弁との間に上流端が接続されて液冷媒を前記圧縮機の吸入側に導く液バイパス配管と、前記液バイパス配管に設けられた液バイパス弁と、前記第１膨張弁と前記第２膨張弁との間に設けられ、冷媒を貯留するレシーバと、前記熱媒体を加熱する加熱運転時に前記圧縮機から吐出された冷媒を前記熱媒体熱交換器へと導き、前記熱媒体を冷却する冷却運転時に前記圧縮機から吐出された冷媒を前記空気熱交換器へと導く切換弁と、前記第１膨張弁、前記レシーバ、及び前記第２膨張弁に対して並列に設けられ、前記熱媒体熱交換器と前記空気熱交換器とを接続する並列冷媒配管と、前記並列冷媒配管に設けられた第３膨張弁と、を備えた熱源機の制御方法であって、前記加熱運転時に、前記第３膨張弁を閉とし、前記第１膨張弁側に冷媒を流すように前記第１膨張弁及び／又は前記第２膨張弁の開度を制御し、前記冷却運転時に、前記第３膨張弁を開とし、前記第２膨張弁側に冷媒を流さないように前記第１膨張弁及び／又は前記第２膨張弁の開度を制御する。 The heat source machine control method according to one aspect of the present disclosure includes a compressor that compresses the refrigerant, a heat medium heat exchanger that exchanges heat between the refrigerant and the heat medium, and an air heat exchanger that exchanges heat between the refrigerant and air. Between the first expansion valve provided on the heat medium heat exchanger side, the second expansion valve provided on the air heat exchanger side, and the heat medium heat exchanger and the first expansion valve. Between the liquid bypass pipe that is connected to the upstream end and guides the liquid refrigerant to the suction side of the compressor, the liquid bypass valve provided in the liquid bypass pipe, and the first expansion valve and the second expansion valve. A receiver for storing the refrigerant and the refrigerant discharged from the compressor during the heating operation for heating the heat medium are guided to the heat medium heat exchanger, and the compression is performed during the cooling operation for cooling the heat medium. A switching valve that guides the refrigerant discharged from the machine to the air heat exchanger is provided in parallel with the first expansion valve, the receiver, and the second expansion valve, and the heat medium heat exchanger and the said. It is a control method of a heat source machine including a parallel refrigerant pipe connecting an air heat exchanger and a third expansion valve provided in the parallel refrigerant pipe, and the third expansion valve is used during the heating operation. The opening of the first expansion valve and / or the second expansion valve is controlled so as to be closed and the refrigerant flows to the first expansion valve side, and the third expansion valve is opened during the cooling operation. The opening degree of the first expansion valve and / or the second expansion valve is controlled so that the refrigerant does not flow to the second expansion valve side.
　本開示の一態様に係る熱源機の制御方法は、冷媒を圧縮する圧縮機と、冷媒と熱媒体とを熱交換する熱媒体熱交換器と、冷媒と空気とを熱交換する空気熱交換器と、前記熱媒体熱交換器側に設けられた第１膨張弁と、前記空気熱交換器側に設けられた第２膨張弁と、前記熱媒体熱交換器と前記第１膨張弁との間に上流端が接続されて液冷媒を前記圧縮機の吸入側に導く液バイパス配管と、前記液バイパス配管に設けられた液バイパス弁と、前記第１膨張弁と前記第２膨張弁との間に設けられ、冷媒を貯留するレシーバと、前記熱媒体を加熱する加熱運転時に前記圧縮機から吐出された冷媒を前記熱媒体熱交換器へと導き、前記熱媒体を冷却する冷却運転時に前記圧縮機から吐出された冷媒を前記空気熱交換器へと導く切換弁と、を備えた熱源機の制御方法であって、前記加熱運転時に、前記圧縮機から吐出される冷媒の温度が所定値以下となるように、前記第１膨張弁の開度を制御する。 The heat source machine control method according to one aspect of the present disclosure includes a compressor that compresses the refrigerant, a heat medium heat exchanger that exchanges heat between the refrigerant and the heat medium, and an air heat exchanger that exchanges heat between the refrigerant and air. Between the first expansion valve provided on the heat medium heat exchanger side, the second expansion valve provided on the air heat exchanger side, and the heat medium heat exchanger and the first expansion valve. Between the liquid bypass pipe that is connected to the upstream end and guides the liquid refrigerant to the suction side of the compressor, the liquid bypass valve provided in the liquid bypass pipe, and the first expansion valve and the second expansion valve. A receiver for storing the refrigerant and the refrigerant discharged from the compressor during the heating operation for heating the heat medium are guided to the heat medium heat exchanger, and the compression is performed during the cooling operation for cooling the heat medium. It is a control method of a heat source machine equipped with a switching valve for guiding the refrigerant discharged from the machine to the air heat exchanger, and the temperature of the refrigerant discharged from the compressor during the heating operation is equal to or lower than a predetermined value. The opening degree of the first expansion valve is controlled so as to be.
１　チラー（熱源機）
３　圧縮機
３ａ　ハウジング
３ｂ　圧縮機構
４　四方弁（切換弁）
５　水熱交換器（熱媒体熱交換器）
６　第１膨張弁
７　レシーバ
８　第２膨張弁
９　空気熱交換器
１０　アキュムレータ
１２　ファン
１４　吐出温度センサ
１６　水配管
１８　外気温センサ
２０　液バイパス配管
２２　液バイパス弁
３０　並列冷媒配管
３２　第３膨張弁 1 Chiller (heat source machine)
3 Compressor 3a Housing 3b Compression mechanism 4 Four-way valve (switching valve)
5 Water heat exchanger (heat medium heat exchanger)
6 1st expansion valve 7 Receiver 8 2nd expansion valve 9 Air heat exchanger 10 Accumulator 12 Fan 14 Discharge temperature sensor 16 Water piping 18 Outside temperature sensor 20 Liquid bypass piping 22 Liquid bypass valve 30 Parallel refrigerant piping 32 3rd expansion valve

Claims (8)

  1. 　冷媒を圧縮する圧縮機と、
    　冷媒と熱媒体とを熱交換する熱媒体熱交換器と、
    　冷媒を膨張させる膨張弁と、
    　冷媒と空気とを熱交換する空気熱交換器と、
    　前記熱媒体熱交換器と前記膨張弁との間に上流端が接続されて液冷媒を前記圧縮機の吸入側に導く液バイパス配管と、
    を備えている熱源機。     A compressor that compresses the refrigerant and
    A heat medium heat exchanger that exchanges heat between the refrigerant and the heat medium,
    An expansion valve that expands the refrigerant and
    An air heat exchanger that exchanges heat between the refrigerant and air,
    A liquid bypass pipe in which an upstream end is connected between the heat medium heat exchanger and the expansion valve to guide the liquid refrigerant to the suction side of the compressor.
    A heat source machine equipped with.
  2. 　前記膨張弁は、前記熱媒体熱交換器側に設けられた第１膨張弁と、前記空気熱交換器側に設けられた第２膨張弁とを備え、
    　前記液バイパス配管の前記上流端は、前記熱媒体熱交換器と前記第１膨張弁との間に接続され、
    　前記第１膨張弁と前記第２膨張弁との間に、冷媒を貯留するレシーバが設けられている請求項１に記載の熱源機。     The expansion valve includes a first expansion valve provided on the heat medium heat exchanger side and a second expansion valve provided on the air heat exchanger side.
    The upstream end of the liquid bypass pipe is connected between the heat medium heat exchanger and the first expansion valve.
    The heat source machine according to claim 1, wherein a receiver for storing a refrigerant is provided between the first expansion valve and the second expansion valve.
  3. 　前記熱媒体を加熱する加熱運転時に前記圧縮機から吐出された冷媒を前記熱媒体熱交換器へと導き、前記熱媒体を冷却する冷却運転時に前記圧縮機から吐出された冷媒を前記空気熱交換器へと導く切換弁と、
    　前記液バイパス配管に設けられた液バイパス弁と、
    　前記加熱運転時で、かつ、前記空気熱交換器の周囲の空気温度が所定値以下とされた場合に、前記液バイパス弁を閉から開へと制御する制御部と、
    を備えている請求項１又は２に記載の熱源機。     The refrigerant discharged from the compressor during the heating operation for heating the heat medium is guided to the heat medium heat exchanger, and the refrigerant discharged from the compressor during the cooling operation for cooling the heat medium is exchanged for air heat. A switching valve that leads to the vessel,
    The liquid bypass valve provided in the liquid bypass pipe and
    A control unit that controls the liquid bypass valve from closed to open during the heating operation and when the air temperature around the air heat exchanger is equal to or lower than a predetermined value.
    The heat source machine according to claim 1 or 2.
  4. 　前記熱媒体を加熱する加熱運転時に前記圧縮機から吐出された冷媒を前記熱媒体熱交換器へと導き、前記熱媒体を冷却する冷却運転時に前記圧縮機から吐出された冷媒を前記空気熱交換器へと導く切換弁と、
    　前記第１膨張弁、前記レシーバ、及び前記第２膨張弁に対して並列に設けられ、前記熱媒体熱交換器と前記空気熱交換器とを接続する並列冷媒配管と、
    　前記並列冷媒配管に設けられた第３膨張弁と、
    　前記加熱運転時に、前記第３膨張弁を閉とし、前記第１膨張弁側に冷媒を流すように前記第１膨張弁及び／又は前記第２膨張弁の開度を制御し、前記冷却運転時に、前記第３膨張弁を開とし、前記第２膨張弁側に冷媒を流さないように前記第１膨張弁及び／又は前記第２膨張弁の開度を制御する制御部と、
    を備えている請求項２に記載の熱源機。     The refrigerant discharged from the compressor during the heating operation for heating the heat medium is guided to the heat medium heat exchanger, and the refrigerant discharged from the compressor during the cooling operation for cooling the heat medium is exchanged for air heat. A switching valve that leads to the vessel,
    A parallel refrigerant pipe provided in parallel with the first expansion valve, the receiver, and the second expansion valve and connecting the heat medium heat exchanger and the air heat exchanger.
    The third expansion valve provided in the parallel refrigerant pipe and
    During the heating operation, the third expansion valve is closed, and the opening degree of the first expansion valve and / or the second expansion valve is controlled so that the refrigerant flows to the first expansion valve side, and during the cooling operation. A control unit that opens the third expansion valve and controls the opening degree of the first expansion valve and / or the second expansion valve so that the refrigerant does not flow to the second expansion valve side.
    The heat source machine according to claim 2.
  5. 　前記熱媒体を加熱する加熱運転時に前記圧縮機から吐出された冷媒を前記熱媒体熱交換器へと導き、前記熱媒体を冷却する冷却運転時に前記圧縮機から吐出された冷媒を前記空気熱交換器へと導く切換弁と、
    　前記液バイパス配管に設けられ、開閉弁とされた液バイパス弁と、
    　前記加熱運転時に、前記圧縮機から吐出される冷媒の温度が所定値以下となるように、前記第１膨張弁の開度を制御する制御部と、
    を備えている請求項２に記載の熱源機。     The refrigerant discharged from the compressor during the heating operation for heating the heat medium is guided to the heat medium heat exchanger, and the refrigerant discharged from the compressor during the cooling operation for cooling the heat medium is exchanged for air heat. A switching valve that leads to the vessel,
    A liquid bypass valve provided in the liquid bypass pipe and used as an on-off valve,
    A control unit that controls the opening degree of the first expansion valve so that the temperature of the refrigerant discharged from the compressor becomes a predetermined value or less during the heating operation.
    The heat source machine according to claim 2.
  6. 　冷媒を圧縮する圧縮機と、
    　冷媒と熱媒体とを熱交換する熱媒体熱交換器と、
    　冷媒を膨張させる膨張弁と、
    　冷媒と空気とを熱交換する空気熱交換器と、
    　前記熱媒体熱交換器と前記膨張弁との間に上流端が接続されて液冷媒を前記圧縮機の吸入側に導く液バイパス配管と、
    　前記液バイパス配管に設けられた液バイパス弁と、
    　前記熱媒体を加熱する加熱運転時に前記圧縮機から吐出された冷媒を前記熱媒体熱交換器へと導き、前記熱媒体を冷却する冷却運転時に前記圧縮機から吐出された冷媒を前記空気熱交換器へと導く切換弁と、
    を備えた熱源機の制御方法であって、
    　前記加熱運転時で、かつ、前記空気熱交換器の周囲の空気温度が所定値以下とされた場合に、前記液バイパス弁を閉から開へと制御する熱源機の制御方法。     A compressor that compresses the refrigerant and
    A heat medium heat exchanger that exchanges heat between the refrigerant and the heat medium,
    An expansion valve that expands the refrigerant and
    An air heat exchanger that exchanges heat between the refrigerant and air,
    A liquid bypass pipe in which an upstream end is connected between the heat medium heat exchanger and the expansion valve to guide the liquid refrigerant to the suction side of the compressor.
    The liquid bypass valve provided in the liquid bypass pipe and
    The refrigerant discharged from the compressor during the heating operation for heating the heat medium is guided to the heat medium heat exchanger, and the refrigerant discharged from the compressor during the cooling operation for cooling the heat medium is exchanged for air heat. A switching valve that leads to the vessel,
    It is a control method of a heat source machine equipped with
    A method for controlling a heat source machine that controls the liquid bypass valve from closed to open during the heating operation and when the air temperature around the air heat exchanger is equal to or lower than a predetermined value.
  7. 　冷媒を圧縮する圧縮機と、
    　冷媒と熱媒体とを熱交換する熱媒体熱交換器と、
    　冷媒と空気とを熱交換する空気熱交換器と、
    　前記熱媒体熱交換器側に設けられた第１膨張弁と、
    　前記空気熱交換器側に設けられた第２膨張弁と、
    　前記熱媒体熱交換器と前記第１膨張弁との間に上流端が接続されて液冷媒を前記圧縮機の吸入側に導く液バイパス配管と、
    　前記液バイパス配管に設けられた液バイパス弁と、
    　前記第１膨張弁と前記第２膨張弁との間に設けられ、冷媒を貯留するレシーバと、
    　前記熱媒体を加熱する加熱運転時に前記圧縮機から吐出された冷媒を前記熱媒体熱交換器へと導き、前記熱媒体を冷却する冷却運転時に前記圧縮機から吐出された冷媒を前記空気熱交換器へと導く切換弁と、
    　前記第１膨張弁、前記レシーバ、及び前記第２膨張弁に対して並列に設けられ、前記熱媒体熱交換器と前記空気熱交換器とを接続する並列冷媒配管と、
    　前記並列冷媒配管に設けられた第３膨張弁と、
    を備えた熱源機の制御方法であって、
    　前記加熱運転時に、前記第３膨張弁を閉とし、前記第１膨張弁側に冷媒を流すように前記第１膨張弁及び／又は前記第２膨張弁の開度を制御し、前記冷却運転時に、前記第３膨張弁を開とし、前記第２膨張弁側に冷媒を流さないように前記第１膨張弁及び／又は前記第２膨張弁の開度を制御する熱源機の制御方法。     A compressor that compresses the refrigerant and
    A heat medium heat exchanger that exchanges heat between the refrigerant and the heat medium,
    An air heat exchanger that exchanges heat between the refrigerant and air,
    The first expansion valve provided on the heat medium heat exchanger side and
    The second expansion valve provided on the air heat exchanger side and
    A liquid bypass pipe in which an upstream end is connected between the heat medium heat exchanger and the first expansion valve to guide the liquid refrigerant to the suction side of the compressor.
    The liquid bypass valve provided in the liquid bypass pipe and
    A receiver provided between the first expansion valve and the second expansion valve to store the refrigerant, and
    The refrigerant discharged from the compressor during the heating operation for heating the heat medium is guided to the heat medium heat exchanger, and the refrigerant discharged from the compressor during the cooling operation for cooling the heat medium is exchanged for air heat. A switching valve that leads to the vessel,
    A parallel refrigerant pipe provided in parallel with the first expansion valve, the receiver, and the second expansion valve and connecting the heat medium heat exchanger and the air heat exchanger.
    The third expansion valve provided in the parallel refrigerant pipe and
    It is a control method of a heat source machine equipped with
    During the heating operation, the third expansion valve is closed, and the opening degree of the first expansion valve and / or the second expansion valve is controlled so that the refrigerant flows to the first expansion valve side, and during the cooling operation. A method for controlling a heat source machine that opens the third expansion valve and controls the opening degree of the first expansion valve and / or the second expansion valve so that the refrigerant does not flow to the second expansion valve side.
  8. 　冷媒を圧縮する圧縮機と、
    　冷媒と熱媒体とを熱交換する熱媒体熱交換器と、
    　冷媒と空気とを熱交換する空気熱交換器と、
    　前記熱媒体熱交換器側に設けられた第１膨張弁と、
    　前記空気熱交換器側に設けられた第２膨張弁と、
    　前記熱媒体熱交換器と前記第１膨張弁との間に上流端が接続されて液冷媒を前記圧縮機の吸入側に導く液バイパス配管と、
    　前記液バイパス配管に設けられた液バイパス弁と、
    　前記第１膨張弁と前記第２膨張弁との間に設けられ、冷媒を貯留するレシーバと、
    　前記熱媒体を加熱する加熱運転時に前記圧縮機から吐出された冷媒を前記熱媒体熱交換器へと導き、前記熱媒体を冷却する冷却運転時に前記圧縮機から吐出された冷媒を前記空気熱交換器へと導く切換弁と、
    を備えた熱源機の制御方法であって、
    　前記加熱運転時に、前記圧縮機から吐出される冷媒の温度が所定値以下となるように、前記第１膨張弁の開度を制御する熱源機の制御方法。     A compressor that compresses the refrigerant and
    A heat medium heat exchanger that exchanges heat between the refrigerant and the heat medium,
    An air heat exchanger that exchanges heat between the refrigerant and air,
    The first expansion valve provided on the heat medium heat exchanger side and
    The second expansion valve provided on the air heat exchanger side and
    A liquid bypass pipe in which an upstream end is connected between the heat medium heat exchanger and the first expansion valve to guide the liquid refrigerant to the suction side of the compressor.
    The liquid bypass valve provided in the liquid bypass pipe and
    A receiver provided between the first expansion valve and the second expansion valve to store the refrigerant, and
    The refrigerant discharged from the compressor during the heating operation for heating the heat medium is guided to the heat medium heat exchanger, and the refrigerant discharged from the compressor during the cooling operation for cooling the heat medium is exchanged for air heat. A switching valve that leads to the vessel,
    It is a control method of a heat source machine equipped with
    A method for controlling a heat source machine that controls the opening degree of the first expansion valve so that the temperature of the refrigerant discharged from the compressor becomes a predetermined value or less during the heating operation.
PCT/JP2021/036974 2020-10-06 2021-10-06 Heat source unit and control method therefor WO2022075358A1 (en)

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JP2001066000A (en) * 1999-08-27 2001-03-16 Hitachi Ltd Heat pump type air conditioner and outdoor unit
JP2011094810A (en) * 2009-09-30 2011-05-12 Fujitsu General Ltd Heat pump cycle apparatus
JP2014119147A (en) * 2012-12-14 2014-06-30 Sharp Corp Air conditioner
JP6005255B2 (en) 2013-03-12 2016-10-12 三菱電機株式会社 Air conditioner
WO2017037771A1 (en) * 2015-08-28 2017-03-09 三菱電機株式会社 Refrigeration cycle device
WO2018185841A1 (en) * 2017-04-04 2018-10-11 三菱電機株式会社 Refrigeration cycle device
JP2019210867A (en) * 2018-06-05 2019-12-12 三菱重工サーマルシステムズ株式会社 Compressor and manufacturing method of the same

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EP3696473B1 (en) * 2017-10-10 2022-08-17 Mitsubishi Electric Corporation Air conditioning device

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JP2001066000A (en) * 1999-08-27 2001-03-16 Hitachi Ltd Heat pump type air conditioner and outdoor unit
JP2011094810A (en) * 2009-09-30 2011-05-12 Fujitsu General Ltd Heat pump cycle apparatus
JP2014119147A (en) * 2012-12-14 2014-06-30 Sharp Corp Air conditioner
JP6005255B2 (en) 2013-03-12 2016-10-12 三菱電機株式会社 Air conditioner
WO2017037771A1 (en) * 2015-08-28 2017-03-09 三菱電機株式会社 Refrigeration cycle device
WO2018185841A1 (en) * 2017-04-04 2018-10-11 三菱電機株式会社 Refrigeration cycle device
JP2019210867A (en) * 2018-06-05 2019-12-12 三菱重工サーマルシステムズ株式会社 Compressor and manufacturing method of the same

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Title
See also references of EP4177545A4

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JP2022061250A (en) 2022-04-18
EP4177545A4 (en) 2024-02-28
EP4177545A1 (en) 2023-05-10

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