WO2024201778A1 - 空気調和装置 - Google Patents

空気調和装置 Download PDF

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Publication number
WO2024201778A1
WO2024201778A1 PCT/JP2023/012806 JP2023012806W WO2024201778A1 WO 2024201778 A1 WO2024201778 A1 WO 2024201778A1 JP 2023012806 W JP2023012806 W JP 2023012806W WO 2024201778 A1 WO2024201778 A1 WO 2024201778A1
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Prior art keywords
flow path
refrigerant
heat source
flows
load
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PCT/JP2023/012806
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English (en)
French (fr)
Japanese (ja)
Inventor
卓 羽入田
傑 鳩村
万誉 篠崎
宗史 池田
孝典 小池
Original Assignee
三菱電機株式会社
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Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to JP2025509394A priority Critical patent/JPWO2024201778A1/ja
Priority to PCT/JP2023/012806 priority patent/WO2024201778A1/ja
Publication of WO2024201778A1 publication Critical patent/WO2024201778A1/ja

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B13/00—Compression machines, plants or systems, with reversible cycle

Definitions

  • This disclosure relates to an air conditioning device equipped with multiple indoor units.
  • Air conditioners equipped with multiple indoor units are known in the past.
  • there are also simultaneous heating and cooling operation type air conditioners in which each indoor unit can perform cooling and heating operations independently.
  • a simultaneous heating and cooling operation type air conditioner can perform heating operation with some of the indoor units and cooling operation with some of the indoor units.
  • a simultaneous heating and cooling operation type air conditioner comprises an outdoor unit which is a heat source unit, a relay unit connected to the outdoor unit by connecting piping, and multiple indoor units connected to the relay unit by connecting piping.
  • the outdoor unit is placed, for example, outside the building.
  • each of the indoor units is placed inside the building.
  • a two-pipe simultaneous heating and cooling operation air conditioner can use an outdoor unit with the same configuration as an outdoor unit of an air conditioner that is not simultaneous heating and cooling operation.
  • the first connecting pipe which is one of the two connecting pipes, carries high-pressure liquid refrigerant that has flowed through the heat source side heat exchanger and the heat source side throttling device, or low-pressure gas-liquid two-phase refrigerant that passes through the heat source side throttling device and flows into the heat source side heat exchanger.
  • the second connecting pipe which is the other of the two connecting pipes, carries low-pressure gas refrigerant sucked into the compressor, or high-pressure gas refrigerant discharged from the compressor.
  • a conventional two-pipe simultaneous heating and cooling operation type air conditioner that aims to suppress changes in the open/close state of the opening and closing device connected to the indoor unit when the refrigerant flow path in the outdoor unit is switched (see Patent Document 1).
  • the two-pipe simultaneous heating and cooling operation type air conditioner described in Patent Document 1 is equipped with a refrigerant flow control unit between the outdoor unit and the repeater.
  • the refrigerant flow control unit and the repeater are connected by two connection pipes.
  • the refrigerant flow control unit and the repeater are connected by a high-pressure connection pipe through which high-pressure refrigerant flows and a low-pressure connection pipe through which low-pressure refrigerant flows.
  • the high-pressure connection pipe used in the two-pipe simultaneous heating and cooling operation type air conditioner described in Patent Document 1 has a larger diameter than the first connection pipe used in a conventional two-pipe simultaneous heating and cooling operation type air conditioner that does not have a refrigerant flow control unit.
  • the two-pipe simultaneous heating and cooling operation type air conditioner described in Patent Document 1 has a larger amount of refrigerant sealed in the air conditioner than a conventional two-pipe simultaneous heating and cooling operation type air conditioner that does not have a refrigerant flow control unit.
  • a conventional two-pipe simultaneous heating and cooling operation type air conditioner that suppresses changes in the open/close state of the opening and closing device connected to the indoor unit has the problem of an increased amount of refrigerant sealed in.
  • the present disclosure has been made to solve the above-mentioned problems, and aims to provide a two-pipe simultaneous heating and cooling air conditioning device that can suppress changes in the open/close state of the opening/closing device connected to the indoor unit when the refrigerant flow path in the outdoor unit is switched, and can also suppress increases in the amount of refrigerant sealed inside.
  • the air conditioning apparatus comprises an outdoor unit, a relay unit connected to the outdoor unit by a first connecting pipe and a second connecting pipe, and a plurality of indoor units connected to the relay unit by connecting pipes
  • the outdoor unit comprises a compressor that compresses and discharges a refrigerant, a heat source side heat exchanger that exchanges heat between the outdoor air and the refrigerant, a heat source side throttling device that is connected to the heat source side heat exchanger and the first connecting pipe and reduces the pressure of the refrigerant flowing between the heat source side heat exchanger and the first connecting pipe, and a heat source side flow path switching device that switches the flow path of the refrigerant flowing through the outdoor unit to a first heat source side flow path where the refrigerant flows out to the first connecting pipe or a second heat source side flow path where the refrigerant flows out to the second connecting pipe
  • each of the indoor units comprises a load side heat exchanger that exchanges heat between a load side heat medium and the refrigerant, and a load
  • the relay flow switching device is connected to the connection port on the opposite side to the connection port to which the load-side throttle device is connected in any of the load-side heat exchangers, and an outflow flow path through which the refrigerant flows from the relay unit to the load-side heat exchanger and an inflow flow path through which the refrigerant flows from the load-side heat exchanger to the relay unit are formed.
  • the outflow flow path is open, the inflow flow path is closed, and when the outflow flow path is closed, the inflow flow path is opened.
  • the relay flow switching device is connected to each of the first connection pipe, the second connection pipe, and the opening and closing device.
  • the relay flow path switching device switches the flow path of the relay flow path switching device, and the open/closed state of the opening and closing device connected to the indoor unit in which the operating mode is the same before and after the flow path switching of the heat source side flow path switching device is made the same before and after the flow path switching of the heat source side flow path switching device.
  • the relay flow path switching device when the refrigerant flow path in the outdoor unit is switched, the relay flow path switching device can suppress changes in the open/close state of the opening/closing device connected to the indoor unit.
  • the air conditioning apparatus according to the present disclosure can be configured so that gas refrigerant does not flow through the first connecting pipe, suppressing an increase in the diameter of the first connecting pipe. Therefore, the air conditioning apparatus according to the present disclosure can also suppress an increase in the amount of refrigerant sealed inside.
  • FIG. 1 is a refrigerant circuit diagram showing an example of a circuit configuration of an air-conditioning apparatus according to a first embodiment in a cooling only operation mode.
  • FIG. 2 is a refrigerant circuit diagram showing the flow of refrigerant in a cooling-dominated operation mode of the air-conditioning apparatus according to the first embodiment.
  • FIG. 2 is a refrigerant circuit diagram showing the flow of refrigerant in a full heating operation mode of the air conditioning apparatus according to the first embodiment.
  • FIG. 2 is a refrigerant circuit diagram showing the flow of refrigerant in a heating-dominated operation mode of the air conditioning apparatus according to the first embodiment.
  • FIG. 11 is a refrigerant circuit diagram showing an example of a circuit configuration of an air-conditioning apparatus according to a second embodiment in a cooling only operation mode.
  • FIG. 11 is a refrigerant circuit diagram showing an example of a circuit configuration of an air-conditioning apparatus according to a second embodiment in a cooling-dominated operation mode.
  • FIG. 11 is a refrigerant circuit diagram showing an example of a circuit configuration of an air conditioning apparatus according to embodiment 3 in a heating only operation mode.
  • FIG. 11 is a refrigerant circuit diagram showing an example of a circuit configuration of an air conditioning apparatus according to embodiment 3 in a heating-dominated operation mode.
  • FIG. 11 is a refrigerant circuit diagram showing an example of a circuit configuration of an air conditioning apparatus according to embodiment 3 in a heating-dominated operation mode.
  • FIG. 11 is a refrigerant circuit diagram showing an example of a circuit configuration of an air conditioning apparatus according to embodiment 4 in a heating only operation mode.
  • FIG. 11 is a refrigerant circuit diagram showing an example of a circuit configuration of an air conditioning apparatus according to embodiment 4 in a heating-dominated operation mode.
  • FIG. 1 is a refrigerant circuit diagram showing an example of a circuit configuration of an air conditioner according to embodiment 1 in a cooling only operation mode.
  • the black arrows shown in Fig. 1 indicate the direction of refrigerant flow when the air conditioner 100 executes a cooling only operation mode described below. Note that in Fig. 1 and Fig. 2 and subsequent figures, when showing opening and closing devices, opening and closing devices in an open state are shown in white, and opening and closing devices in a closed state are shown in black.
  • the air conditioning device 100 circulates a refrigerant and performs air conditioning using a refrigeration cycle.
  • the air conditioning device 100 includes an outdoor unit 101, a relay unit 102, and a plurality of indoor units 103.
  • an alphabet is added to the end of the reference numeral.
  • components included in each indoor unit 103 are to be distinguished, the same alphabet as that added to each indoor unit 103 is added to the end of the reference numeral.
  • components connected to each indoor unit 103 are to be distinguished, the same alphabet as that added to each indoor unit 103 is added to the end of the reference numeral.
  • FIG. 1 shows an example of an air conditioning device 100 including four indoor units 103.
  • FIG. 1 shows an air conditioning device 100 including indoor units 103a to 103d.
  • the number of indoor units 103 included in the air conditioning device 100 is not limited to four as long as it is a plurality of indoor units 103.
  • the outdoor unit 101 and the repeater unit 102 are connected by two connection pipes. Specifically, the outdoor unit 101 and the repeater unit 102 are connected by a first connection pipe 7 and a second connection pipe 8. Furthermore, each of the indoor units 103 is connected to the repeater unit 102 by two connection pipes. Specifically, each of the indoor units 103 is connected to the repeater unit 102 by a connection pipe 9a and a connection pipe 9b. Each of the indoor units 103 is connected in parallel to the repeater unit 102.
  • Each indoor unit 103 can execute a cooling operation mode and a heating operation mode as the operation mode of the indoor unit 103.
  • the cooling operation mode is an operation mode in which the indoor unit 103 performs cooling operation.
  • the heating operation mode is an operation mode in which the indoor unit 103 performs heating operation.
  • the air conditioning device 100 is also configured to be able to select an all-cooling operation mode, an all-heating operation mode, a cooling-dominated operation mode, and a heating-dominated operation mode as the operation mode of the air conditioning device 100.
  • the all-cooling operation mode is an operation mode in which all operating indoor units 103 perform cooling operation.
  • the all-heating operation mode is an operation mode in which all operating indoor units 103 perform heating operation.
  • the cooling-dominated operation mode is an operation mode in which indoor units 103 performing cooling operation and indoor units 103 performing heating operation are mixed, and the ratio of cooling operation is high.
  • the cooling-dominated operation mode is an operation mode in which the indoor units 103 performing cooling operation and the indoor units 103 performing heating operation are mixed, and the cooling load is greater than the heating load.
  • the heating-dominated operation mode is an operation mode in which the indoor units 103 performing cooling operation and the indoor units 103 performing heating operation are mixed, and the ratio of heating operation is high.
  • the heating-dominated operation mode is an operation mode in which the indoor units 103 performing cooling operation and the indoor units 103 performing heating operation are mixed, and the heating load is greater than the cooling load.
  • the outdoor unit 101 includes a compressor 1, a heat source-side flow switching device 2, a heat source-side heat exchanger 3, and a heat source-side throttle device 5.
  • the outdoor unit 101 also includes an outdoor fan 4 and a control device 6.
  • the compressor 1 compresses and discharges a refrigerant. Specifically, the compressor 1 sucks in a low-temperature, low-pressure gas refrigerant, compresses it, and discharges a high-temperature, high-pressure gas refrigerant.
  • the compressor 1 circulates the refrigerant in a refrigerant circuit.
  • the compressor 1 is, for example, an inverter-type compressor whose capacity is controllable.
  • the heat source side heat exchanger 3 exchanges heat between the outdoor air and the refrigerant.
  • One connection port of the heat source side heat exchanger 3 is connected to the heat source side flow switching device 2.
  • the other connection port of the heat source side heat exchanger 3 is connected to the heat source side throttling device 5.
  • the heat source side heat exchanger 3 is, for example, a fin tube type heat exchanger.
  • the heat source side heat exchanger 3 exchanges heat between the outdoor air supplied by the outdoor fan 4 and the refrigerant.
  • the heat source side heat exchanger 3 functions as a condenser during cooling operation, condensing and liquefying the refrigerant.
  • the heat source side heat exchanger 3 functions as an evaporator during heating operation, evaporating and gasifying the refrigerant.
  • the outdoor fan 4 is, for example, a propeller fan.
  • the outdoor fan 4 supplies outdoor air around the outdoor unit 101 to the heat source side heat exchanger 3.
  • the rotation speed of the outdoor fan 4 is controlled by the control device 6, thereby controlling the condensation capacity or evaporation capacity of the heat source side heat exchanger 3.
  • the heat source side throttling device 5 is connected to the heat source side heat exchanger 3 and the first connecting pipe 7, and reduces the pressure of the refrigerant flowing between the heat source side heat exchanger 3 and the first connecting pipe 7.
  • the heat source side throttling device 5 is, for example, an electronic expansion valve that can adjust the throttling opening. By adjusting the opening, the heat source side throttling device 5 controls the refrigerant pressure flowing into the relay unit 102 in the full cooling operation mode and the cooling-dominated operation mode, and controls the refrigerant pressure flowing into the heat source side heat exchanger 3 in the full heating operation mode and the heating-dominated operation mode.
  • the heat source side flow path switching device 2 switches the flow path of the refrigerant flowing through the outdoor unit 101 to the first heat source side flow path 2a or the second heat source side flow path 2b.
  • the first heat source side flow path 2a is a flow path through which the refrigerant flows out from the outdoor unit 101 to the first connecting pipe 7.
  • the second heat source side flow path 2b is a flow path through which the refrigerant flows out from the outdoor unit 101 to the second connecting pipe 8.
  • the heat source side flow path switching device 2 is, for example, a four-way valve.
  • the heat source side flow path switching device 2 switches the connection destination of the discharge port of the compressor 1 to one of the heat source side heat exchanger 3 and the second connecting pipe 8 depending on the operation mode of the air conditioning device 100.
  • the heat source side flow path switching device 2 switches the connection destination of the suction port of the compressor 1 to the other of the heat source side heat exchanger 3 and the second connecting pipe 8 depending on the operation mode of the air conditioning device 100.
  • the heat source side flow path switching device 2 can switch the flow path of the refrigerant flowing through the outdoor unit 101 to the first heat source side flow path 2a or the second heat source side flow path 2b depending on the operation mode of the air conditioning device 100.
  • the heat source side flow path switching device 2 is switched to the first heat source side flow path 2a in the full cooling operation mode and the cooling-dominated operation mode, and is switched to the second heat source side flow path 2b in the full heating operation mode and the heating-dominated operation mode.
  • the heat source side flow path switching device 2 may be a combination of a three-way valve or a two-way valve.
  • the control device 6 controls the operation of the compressor 1, the heat source side flow switching device 2, the outdoor fan 4, and the heat source side throttle device 5. Specifically, the control device 6 controls the drive frequency of the compressor 1, the flow path of the heat source side flow switching device 2, the rotation speed of the outdoor fan 4, and the opening degree of the heat source side throttle device 5 based on the detection results of the sensors mounted on the outdoor unit 101.
  • the sensors mounted on the outdoor unit 101 include, for example, a discharge pressure sensor 50 that detects the pressure of the refrigerant discharged from the compressor 1, a discharge temperature sensor 51 that detects the temperature of the refrigerant discharged from the compressor 1, a heat source side heat exchanger temperature sensor 52 that detects the temperature of the refrigerant flowing out from the heat source side heat exchanger 3, and an outdoor air temperature sensor 53 that detects the outdoor air temperature.
  • the temperature sensor is, for example, a thermistor.
  • the control device 6 can perform data communication with the control device 19 mounted on the relay unit 102.
  • the control device 6 can also perform data communication with the control device 13 mounted on each indoor unit 103.
  • the control device 6 mounted in the outdoor unit 101, the control device 19 mounted in the relay unit 102 (to be described later), and the control device 13 mounted in the indoor unit 103 (to be described later) are configured, for example, as follows.
  • the control devices 6, 19, and 13 are configured with dedicated hardware or a CPU (Central Processing Unit) that executes a program stored in a memory.
  • the CPU is also called a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, or a processor.
  • control devices 6, 19, and 13 are dedicated hardware
  • the control devices 6, 19, and 13 are, for example, a single circuit, a composite circuit, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination of these.
  • Each of the functional units realized by the control devices 6, 19, and 13 may be realized by separate hardware, or each functional unit may be realized by a single piece of hardware.
  • control devices 6, 19, and 13 are CPUs
  • the functions executed by the control devices 6, 19, and 13 are realized by software, firmware, or a combination of software and firmware.
  • Software and firmware are written as programs and stored in memory.
  • the CPU realizes the functions of the control devices 6, 19, and 13 by reading and executing the programs stored in memory.
  • the memory is, for example, a non-volatile or volatile semiconductor memory such as a RAM, ROM, flash memory, EPROM, or EEPROM.
  • control devices 6, 19, and 13 may be configured to realize some of their functions using dedicated hardware and some of their functions using software or firmware.
  • Each of the indoor units 103 includes a load side heat exchanger 10 and a load side expansion device 11.
  • each of the indoor units 103 includes an indoor fan 12 and a control device 13. That is, the indoor unit 103a includes a load side heat exchanger 10a, a load side expansion device 11a, an indoor fan 12a, and a control device 13a.
  • the indoor unit 103b includes a load side heat exchanger 10b, a load side expansion device 11b, an indoor fan 12b, and a control device 13b.
  • the indoor unit 103c includes a load side heat exchanger 10c, a load side expansion device 11c, an indoor fan 12c, and a control device 13c.
  • the indoor unit 103d includes a load side heat exchanger 10d, a load side expansion device 11d, an indoor fan 12d, and a control device 13d.
  • the load side heat exchanger 10 exchanges heat between the load side heat medium and the refrigerant.
  • the load side heat medium is the object of heat exchange for the refrigerant flowing through the load side heat exchanger 10.
  • the load side heat medium is indoor air.
  • the load side heat exchanger 10 is, for example, a fin tube type heat exchanger.
  • the load side heat exchanger 10 exchanges heat with the indoor air supplied by the indoor fan 12 to generate air for cooling or air for heating to be supplied to the space to be air-conditioned.
  • the load side heat exchanger 10 may be a plate type heat exchanger in which the refrigerant exchanges heat with water, antifreeze, or the like. In other words, the load side heat medium may be water, antifreeze, or the like.
  • the load side throttling device 11 is connected to the load side heat exchanger 10 and reduces the pressure of the refrigerant to adjust the amount of refrigerant flowing into the load side heat exchanger 10.
  • the load side throttling device 11 is, for example, an electronic expansion valve whose opening can be adjusted continuously or in multiple stages.
  • the load side throttling device 11 is connected in series with the load side heat exchanger 10 and reduces the pressure of the refrigerant flowing into the load side heat exchanger 10 to expand it.
  • the load side throttling device 11 is provided upstream of the load side heat exchanger 10 in the refrigerant flow in the full cooling operation mode.
  • the control device 13 controls the rotation speed of the indoor fan 12 and the opening degree of the load side throttle device 11.
  • the relay unit 102 includes a plurality of opening and closing devices 30 and a relay flow path switching device 14. In the first embodiment, the relay unit 102 also includes a gas-liquid separator 17, a relay throttle device 18, and a control device 19.
  • the gas-liquid separator 17 separates the gas-liquid two-phase refrigerant that flows into the relay unit 102 from the first connection pipe 7 into a liquid refrigerant that flows into at least one of the load-side throttling devices 11 of the indoor units 103, and a gas refrigerant that flows into at least one of the opening and closing devices 30.
  • the gas-liquid two-phase refrigerant inlet 17a of the gas-liquid separator 17 is connected to the first connection pipe 7.
  • the gas refrigerant outlet 17b of the gas-liquid separator 17 is connected to the first flow path 14a (described later) of the relay flow path switching device 14.
  • the gas refrigerant outlet 17b of the gas-liquid separator 17 is connected to each of the opening and closing devices 30 via the relay flow path switching device 14.
  • the liquid refrigerant outlet 17c of the gas-liquid separator 17 is connected to the load-side throttling device 11 of each indoor unit 103.
  • the gas-liquid separator 17 separates the high-pressure gas-liquid two-phase refrigerant generated in the outdoor unit 101 into liquid refrigerant and gas refrigerant.
  • the gas-liquid separator 17 then discharges the separated liquid refrigerant from outlet 17c to supply cold heat to some of the indoor units 103.
  • the gas-liquid separator 17 also discharges the separated gas refrigerant from outlet 17b to supply hot heat to some of the indoor units 103.
  • the air conditioning device 100 includes an opening/closing device 30a connected to the indoor unit 103a, an opening/closing device 30b connected to the indoor unit 103b, an opening/closing device 30c connected to the indoor unit 103c, and an opening/closing device 30d connected to the indoor unit 103d. That is, each of the opening/closing devices 30 is connected to one of the load side heat exchangers 10 of the indoor units 103. In the first embodiment, specifically, the opening/closing device 30 is connected to a connection port on the opposite side to the connection port to which the load side throttle device 11 is connected in the load side heat exchanger 10.
  • Each opening/closing device 30 has an outflow flow path and an inflow flow path.
  • the outflow flow path is a flow path through which the refrigerant flows from the relay unit 102 to the load side heat exchanger 10.
  • the inflow flow path is a flow path through which the refrigerant flows from the load side heat exchanger 10 to the relay unit 102.
  • the opening and closing device 30 is configured to close the inflow passage when the outflow passage is open, and to open the inflow passage when the outflow passage is closed.
  • each of the opening and closing devices 30 has the following configuration.
  • Each of the opening and closing devices 30 has a first opening and closing device 31 and a second opening and closing device 32 connected in parallel to the load side heat exchanger 10. That is, the opening and closing device 30a has a first opening and closing device 31a and a second opening and closing device 32a connected in parallel to the load side heat exchanger 10a.
  • the opening and closing device 30b has a first opening and closing device 31b and a second opening and closing device 32b connected in parallel to the load side heat exchanger 10b.
  • the opening and closing device 30c has a first opening and closing device 31c and a second opening and closing device 32c connected in parallel to the load side heat exchanger 10c.
  • the opening and closing device 30d has a first opening and closing device 31d and a second opening and closing device 32d connected in parallel to the load side heat exchanger 10d.
  • the first opening/closing device 31 is configured to be able to freely open and close the flow path formed in the first opening/closing device 31.
  • the flow path formed in the first opening/closing device 31 becomes the outflow flow path.
  • a high-temperature, high-pressure gas refrigerant to be supplied to the load-side heat exchanger 10 flows in the flow path formed in the first opening/closing device 31.
  • the first opening/closing device 31 is configured, for example, with a solenoid valve. Note that the first opening/closing device 31 may be a throttling device with a full closing function as long as it is capable of opening and closing the flow path.
  • the second opening/closing device 32 is configured to be able to freely open and close the flow path formed in the second opening/closing device 32.
  • the flow path formed in the second opening/closing device 32 becomes the inflow flow path.
  • the low-pressure, low-temperature gas refrigerant flowing out from the load-side heat exchanger 10 flows in the flow path formed in the second opening/closing device 32.
  • the second opening/closing device 32 is configured, for example, with a solenoid valve.
  • the second opening/closing device 32 may be a throttling device with a full closing function as long as it is capable of opening and closing the flow path.
  • the opening/closing device 30 is not limited to a configuration including the first opening/closing device 31 and the second opening/closing device 32.
  • the opening/closing device 30 may be configured with a three-way valve.
  • the relay flow path switching device 14 is connected to each of the first connection pipe 7, the second connection pipe 8, and the opening and closing device 30.
  • the relay flow path switching device 14 is connected to the first connection pipe 7 via a gas-liquid separator 17.
  • the relay flow path switching device 14 is configured to switch the flow path as follows when the flow path of the heat source side flow path switching device 2 is switched. Specifically, there may be indoor units 103 whose operation mode is the same before and after the flow path switching of the heat source side flow path switching device 2. For example, there may be indoor units 103 whose operation mode remains in the cooling operation mode before and after the flow path switching of the heat source side flow path switching device 2.
  • the relay flow path switching device 14 is configured to keep the open/closed state of the opening/closing device 30 connected to the indoor unit 103, which has the same operating mode before and after switching of the flow path of the heat source side flow path switching device 2, the same before and after switching of the flow path of the heat source side flow path switching device 2.
  • the relay flow path switching device 14 is formed with a first flow path 14a that can be opened and closed, a second flow path 14b that can be opened and closed, a third flow path 14c that can be opened and closed, and a fourth flow path 14d that can be opened and closed.
  • the first flow path 14a is a flow path that connects the first connection pipe 7 and each of the outflow flow paths of the opening and closing device 30.
  • the first flow path 14a is a flow path that connects the first connection pipe 7 and each of the first opening and closing devices 31.
  • the second flow path 14b is a flow path that connects the second connection pipe 8 and each of the inflow flow paths of the opening and closing device 30.
  • the second flow path 14b is a flow path that connects the second connection pipe 8 and each of the second opening and closing devices 32.
  • the third flow path 14c is a flow path that connects the second connection pipe 8 and each of the outflow flow paths of the opening and closing device 30.
  • the third flow path 14c is a flow path that connects the second connection pipe 8 and each of the first opening and closing devices 31.
  • the fourth flow path 14d is a flow path that connects the first connection pipe 7 and each of the inlet flow paths of the opening and closing device 30.
  • the fourth flow path 14d is a flow path that connects the first connection pipe 7 and each of the second opening and closing devices 32.
  • the heat source side flow path switching device 2 When the air conditioning device 100 is operating in a cooling only operation mode or a cooling-dominated operation mode, the heat source side flow path switching device 2 becomes the first heat source side flow path 2a. When the heat source side flow path switching device 2 is in the first heat source side flow path 2a, the relay flow path switching device 14 opens the first flow path 14a and the second flow path 14b, and closes the third flow path 14c and the fourth flow path 14d. When the air conditioning device 100 is operating in a heating only operation mode or a heating-dominated operation mode, the heat source side flow path switching device 2 becomes the second heat source side flow path 2b.
  • the relay flow path switching device 14 opens the third flow path 14c and the fourth flow path 14d, and closes the first flow path 14a and the second flow path 14b.
  • the relay flow path switching device 14 can make the open/closed state of the opening/closing device 30 connected to the indoor unit 103, which has the same operating mode before and after the flow path switching of the heat source side flow path switching device 2, the same before and after the flow path switching of the heat source side flow path switching device 2.
  • the switching of the open/closed states of the first flow path 14a, the second flow path 14b, the third flow path 14c, and the fourth flow path 14d of the heat source side flow path switching device 2 is controlled by the control device 19.
  • the control device 19 switches the open/closed states of the first flow path 14a, the second flow path 14b, the third flow path 14c, and the fourth flow path 14d, for example, at the same timing as the flow paths of the heat source side flow path switching device 2 are switched.
  • the repeater throttle device 18 is provided in the refrigerant piping that connects the gas-liquid separator 17 and the load side throttle device 11.
  • the repeater throttle device 18 functions as a pressure reducing valve and an on-off valve.
  • the repeater throttle device 18 reduces the pressure of the liquid refrigerant to a predetermined pressure, and opens and closes the flow path of the liquid refrigerant.
  • the repeater throttle device 18 can variably adjust the opening degree, for example, continuously or in multiple stages. For example, an electronic expansion valve or the like is used as the repeater throttle device 18.
  • the control device 19 controls the relay flow path switching device 14. Specifically, the control device 19 controls the open/close state of each flow path of the relay flow path switching device 14. The control device 19 also controls the opening degree of the relay throttle device 18 and the open/close state of the opening/closing device 30. In other words, the control device 19 controls the open/close state of the first opening/closing device 31 and the second opening/closing device 32.
  • the various operation modes implemented by the air conditioning device 100 will be described.
  • the operation modes implemented by the air conditioning device 100 include the full cooling operation mode, the cooling-dominated operation mode, the full heating operation mode, and the heating-dominated operation mode. Each operation mode will be described below.
  • Fig. 1 illustrates a case where a cooling load is generated in all of the load side heat exchangers 10a to 10d.
  • the control device 6 switches the flow path of the heat source side flow path switching device 2 of the outdoor unit 101 to the first heat source side flow path 2a.
  • the control device 6 switches the flow path of the heat source side flow path switching device 2 of the outdoor unit 101 to a flow path through which the refrigerant discharged from the compressor 1 flows into the heat source side heat exchanger 3.
  • the control device 19 also controls the relay flow path switching device 14 to open the first flow path 14a and the second flow path 14b and close the third flow path 14c and the fourth flow path 14d.
  • the compressor 1 When the compressor 1 is driven, it compresses low-temperature, low-pressure refrigerant and discharges it as high-temperature, high-pressure gas refrigerant.
  • the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 flows into the heat source side heat exchanger 3 via the heat source side flow switching device 2.
  • the high-temperature, high-pressure gas refrigerant that flows into the heat source side heat exchanger 3 then becomes high-pressure liquid refrigerant while releasing heat to the outdoor air.
  • the high-pressure liquid refrigerant that flows out of the heat source side heat exchanger 3 flows out of the outdoor unit 101, passes through the first connecting pipe 7, and flows into the relay unit 102.
  • the high-pressure liquid refrigerant that flows into the relay unit 102 passes through the gas-liquid separator 17, the relay unit throttling device 18, and the connecting pipe 9b, and flows into each indoor unit 103.
  • the high-pressure liquid refrigerant that flows into each indoor unit 103 is decompressed and expanded by the load-side throttling device 11, becoming a low-temperature, low-pressure, two-phase gas-liquid refrigerant.
  • This two-phase gas-liquid refrigerant flows into the load-side heat exchanger 10, which functions as an evaporator, and absorbs heat from the indoor air, cooling the indoor air and becoming a low-temperature, low-pressure gas refrigerant.
  • each indoor unit 103 is equipped with a load-side first temperature sensor 54 that detects the temperature of the refrigerant flowing into the load-side heat exchanger 10 when the load-side heat exchanger 10 functions as an evaporator.
  • the load-side first temperature sensor 54 detects the temperature of the refrigerant flowing out of the load-side heat exchanger 10 when the load-side heat exchanger 10 functions as a condenser.
  • Each indoor unit 103 is also equipped with a load-side second temperature sensor 55 that detects the temperature of the refrigerant flowing out of the load-side heat exchanger 10 when the load-side heat exchanger 10 functions as an evaporator.
  • the opening degree of the load-side throttling device 11 of each indoor unit 103 is controlled by the control device 13 so that the superheat obtained as the difference between the temperature detected by the load-side first temperature sensor 54 and the temperature detected by the load-side second temperature sensor 55 is constant.
  • the superheat is sometimes called the degree of superheat.
  • the low-temperature, low-pressure gas refrigerant that flows out of the load-side heat exchanger 10 of each indoor unit 103 flows out of each indoor unit 103 and flows into the repeater 102 through the connection pipe 9a.
  • the low-temperature, low-pressure gas refrigerant that flows into the repeater 102 from each indoor unit 103 passes through the second opening and closing device 32 of the opening and closing device 30 and merges.
  • This merged low-temperature, low-pressure gas refrigerant flows out of the repeater 102 through the second flow path 14b of the relay flow path switching device 14 and flows back into the outdoor unit 101 through the second connection pipe 8.
  • the low-temperature, low-pressure gas refrigerant that flows into the outdoor unit 101 flows back into the compressor 1 through the heat source side flow path switching device 2 and is sucked back into the compressor 1.
  • FIG. 2 is a refrigerant circuit diagram showing the flow of refrigerant in the cooling-dominated operation mode of the air conditioner according to embodiment 1.
  • the cooling-dominated operation mode is explained using an example in which the indoor units 103b, 103c, and 103d perform cooling operation, and the indoor unit 103a performs heating operation.
  • Fig. 2 illustrates a case in which a cold load is generated in the load-side heat exchanger 10b, 10c, and 10d, and a warm load is generated in the load-side heat exchanger 10a.
  • the control device 6 switches the flow path of the heat source side flow path switching device 2 of the outdoor unit 101 to the first heat source side flow path 2a.
  • the control device 6 switches the flow path of the heat source side flow path switching device 2 of the outdoor unit 101 to a flow path through which the refrigerant discharged from the compressor 1 flows into the heat source side heat exchanger 3.
  • the control device 19 also controls the relay flow path switching device 14 to open the first flow path 14a and the second flow path 14b and close the third flow path 14c and the fourth flow path 14d.
  • the compressor 1 When the compressor 1 is driven, it compresses low-temperature, low-pressure refrigerant and discharges it as high-temperature, high-pressure gas refrigerant.
  • the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 flows into the heat source-side heat exchanger 3 via the heat source-side flow switching device 2.
  • the high-temperature, high-pressure gas refrigerant that flows into the heat source-side heat exchanger 3 becomes a high-pressure two-phase gas-liquid refrigerant while releasing heat to the outdoor air.
  • the high-pressure two-phase gas-liquid refrigerant that flows out of the heat source-side heat exchanger 3 flows out of the outdoor unit 101, passes through the first connecting pipe 7, and flows into the relay unit 102.
  • the high-pressure gas-liquid two-phase refrigerant that flows into the relay unit 102 is separated into high-pressure gas refrigerant and high-pressure liquid refrigerant by the gas-liquid separator 17.
  • This high-pressure gas refrigerant flows through the first flow path 14a of the relay flow path switching device 14, the first opening and closing device 31a, and the connecting pipe 9a, before flowing into the indoor unit 103a.
  • the high-pressure gas refrigerant that flows into the indoor unit 103a then flows into the load side heat exchanger 10a, which functions as a condenser, and dissipates heat into the indoor air, thereby becoming high-pressure liquid refrigerant while heating the indoor air.
  • the load-side throttling device 11a of the indoor unit 103a is controlled by the control device 13a as follows.
  • the relay unit 102 is equipped with an inlet-side pressure sensor 56 that detects the pressure of the liquid refrigerant flowing out of the gas-liquid separator 17 and flowing into the relay-side throttling device 18. Since the gas refrigerant flowing into the load-side heat exchanger 10a is the gas refrigerant flowing out of the gas-liquid separator 17, the pressure of the gas refrigerant is approximately the same as the pressure of the liquid refrigerant detected by the inlet-side pressure sensor 56.
  • the liquid refrigerant flowing out from the load side heat exchanger 10a is depressurized and expanded in the load side throttling device 11a, and flows into the relay 102 through the connecting pipe 9b.
  • This refrigerant is merged with the medium pressure liquid refrigerant that has been separated in the gas-liquid separator 17 and expanded to medium pressure in the relay throttling device 18.
  • the relay throttling device 18 is controlled by the control device 19 as follows.
  • the relay 102 is equipped with an outlet side pressure sensor 57 that detects the pressure of the refrigerant flowing out from the relay throttling device 18.
  • the above-mentioned merged liquid refrigerant flows into indoor unit 103b, indoor unit 103c, and indoor unit 103d via connection pipe 9b.
  • the refrigerant that flows into indoor unit 103b is decompressed and expanded by load side throttling device 11b, becoming a low-temperature, low-pressure, two-phase gas-liquid refrigerant, which flows into load side heat exchanger 10b, which functions as an evaporator.
  • the low-temperature, low-pressure, two-phase gas-liquid refrigerant that flows into load side heat exchanger 10b absorbs heat from the indoor air, cooling the indoor air and becoming a low-temperature, low-pressure gas refrigerant.
  • the opening degree of load side throttling device 11b is controlled by control device 13b so that the superheat obtained as the difference between the temperature detected by load side first temperature sensor 54b and the temperature detected by load side second temperature sensor 55b is constant.
  • the refrigerant that flows into the indoor unit 103c is decompressed and expanded by the load side throttling device 11c, becoming a low-temperature, low-pressure, two-phase gas-liquid refrigerant that flows into the load side heat exchanger 10c, which functions as an evaporator.
  • the low-temperature, low-pressure, two-phase gas-liquid refrigerant that flows into the load side heat exchanger 10c absorbs heat from the indoor air, cooling it and becoming a low-temperature, low-pressure gas refrigerant.
  • the opening degree of the load side throttling device 11d is controlled by the control device 13d so that the superheat obtained as the difference between the temperature detected by the load side first temperature sensor 54d and the temperature detected by the load side second temperature sensor 55d is constant.
  • the low-temperature, low-pressure gas refrigerant flowing out of the load-side heat exchanger 10b flows into the second opening/closing device 32b through the connecting pipe 9a.
  • the low-temperature, low-pressure gas refrigerant flowing out of the load-side heat exchanger 10c flows into the second opening/closing device 32c through the connecting pipe 9a.
  • the low-temperature, low-pressure gas refrigerant flowing out of the load-side heat exchanger 10d flows into the second opening/closing device 32d through the connecting pipe 9a.
  • the control device 6 switches the flow path of the heat source side flow path switching device 2 of the outdoor unit 101 to the second heat source side flow path 2b.
  • the control device 6 switches the flow path of the heat source side flow path switching device 2 of the outdoor unit 101 to a flow path in which the refrigerant discharged from the compressor 1 flows into the relay unit 102 without passing through the heat source side heat exchanger 3.
  • the control device 19 controls the relay flow path switching device 14 to open the third flow path 14c and the fourth flow path 14d and close the first flow path 14a and the second flow path 14b.
  • the compressor 1 When the compressor 1 is driven, it compresses the low-temperature, low-pressure refrigerant and discharges it as high-temperature, high-pressure gas refrigerant.
  • the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 passes through the heat source side flow switching device 2 and flows out of the outdoor unit 101.
  • the high-temperature, high-pressure gas refrigerant flowing out of the outdoor unit 101 flows into the relay unit 102 through the second connection pipe 8.
  • the high-temperature, high-pressure gas refrigerant that flows into the repeater 102 flows into each indoor unit 103 via the third flow path 14c of the repeater flow path switching device 14, the first opening and closing device 31 connected to each indoor unit 103, and the connecting pipe 9a.
  • the high-temperature, high-pressure gas refrigerant that flows into each indoor unit 103 flows into the load side heat exchanger 10, which functions as a condenser.
  • the high-temperature, high-pressure gas refrigerant does not pass through a gas-liquid separator, so pressure loss can be reduced.
  • the refrigerant that flows into the load side heat exchanger 10 becomes liquid refrigerant by releasing heat to the indoor air, heating the indoor air.
  • the liquid refrigerant that flows out of the load side heat exchanger 10 is decompressed and expanded by the load side throttle device 11, becoming a low-temperature, low-pressure gas-liquid two-phase refrigerant, which flows into the repeater 102 through the connecting pipe 9b.
  • the load side throttle device 11 is controlled by the control device 13 to open at a constant subcooling level, which is the difference between the pressure detected by the discharge pressure sensor 50 converted to saturation temperature and the temperature detected by the load side first temperature sensor 54.
  • the low-temperature, low-pressure, two-phase gas-liquid refrigerant that flows from each indoor unit 103 to the relay unit 102 merges and then flows through the bypass piping 20, the fourth flow path 14d of the relay flow path switching device 14, the gas-liquid separator 17, and the first connection piping 7 before flowing into the outdoor unit 101.
  • the low-temperature, low-pressure, two-phase gas-liquid refrigerant becomes a low-temperature, low-pressure gas refrigerant while absorbing heat from the outdoor air in the heat source side heat exchanger 3, and is sucked back into the compressor 1 via the heat source side flow path switching device 2.
  • FIG. 4 is a refrigerant circuit diagram showing the flow of refrigerant in the heating-dominated operation mode of the air conditioner according to embodiment 1.
  • the heating-dominated operation mode is explained using an example in which the indoor units 103b, 103c, and 103d perform heating operation, and the indoor unit 103a performs cooling operation.
  • Fig. 4 illustrates a case in which a hot heat load is generated in the load-side heat exchanger 10b, 10c, and 10d, and a cold heat load is generated in the load-side heat exchanger 10a.
  • the control device 6 switches the flow path of the heat source-side flow path switching device 2 of the outdoor unit 101 to the second heat source-side flow path 2b.
  • the control device 6 switches the flow path of the heat source-side flow path switching device 2 of the outdoor unit 101 to a flow path in which the refrigerant discharged from the compressor 1 flows into the relay unit 102 without passing through the heat source-side heat exchanger 3.
  • the control device 19 also controls the relay flow path switching device 14 to open the third flow path 14c and the fourth flow path 14d and close the first flow path 14a and the second flow path 14b.
  • the compressor 1 When the compressor 1 is driven, it compresses the low-temperature, low-pressure refrigerant and discharges it as high-temperature, high-pressure gas refrigerant.
  • the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 passes through the heat source side flow switching device 2 and flows out of the outdoor unit 101.
  • the high-temperature, high-pressure gas refrigerant flowing out of the outdoor unit 101 flows into the relay unit 102 through the second connection pipe 8.
  • the high-temperature, high-pressure gas refrigerant that flows into the relay unit 102 flows through the third flow path 14c of the relay flow path switching device 14 into the first opening/closing device 31b, the first opening/closing device 31c, and the first opening/closing device 31b.
  • the high-temperature, high-pressure gas refrigerant that flows into the first opening/closing device 31b flows into the indoor unit 103b through the connection pipe 9a.
  • the high-temperature, high-pressure gas refrigerant that flows into the first opening/closing device 31c flows into the indoor unit 103c through the connection pipe 9a.
  • the high-temperature, high-pressure gas refrigerant does not pass through the gas-liquid separator, so pressure loss can be reduced.
  • the high-temperature, high-pressure gas refrigerant that flows into the indoor unit 103b flows into the load-side heat exchanger 10b, which functions as a condenser.
  • the high-temperature, high-pressure gas refrigerant that flows into the load-side heat exchanger 10b dissipates heat to the indoor air, turning into liquid refrigerant while heating the indoor air.
  • the liquid refrigerant that flows out of the load-side heat exchanger 10b is depressurized and expanded by the load-side throttling device 11b, and flows into the repeater 102 via the connecting pipe 9b.
  • the high-temperature, high-pressure gas refrigerant that flows into the indoor unit 103c flows into the load-side heat exchanger 10c, which functions as a condenser.
  • the high-temperature, high-pressure gas refrigerant that flows into the load-side heat exchanger 10c dissipates heat to the indoor air, turning into liquid refrigerant while heating the indoor air.
  • the liquid refrigerant that flows out of the load-side heat exchanger 10c is depressurized and expanded by the load-side throttling device 11c, and flows into the repeater 102 via the connecting pipe 9b.
  • the high-temperature, high-pressure gas refrigerant that flows into the indoor unit 103d flows into the load-side heat exchanger 10d, which functions as a condenser.
  • the high-temperature, high-pressure gas refrigerant that flows into the load-side heat exchanger 10d dissipates heat into the indoor air, heating the indoor air and becoming liquid refrigerant.
  • the liquid refrigerant that flows out of the load-side heat exchanger 10d is depressurized and expanded by the load-side throttle device 11d, and flows into the relay unit 102 via the connection pipe 9b.
  • the liquid refrigerant flowing into the relay unit 102 from the indoor unit 103b, the liquid refrigerant flowing into the relay unit 102 from the indoor unit 103c, and the liquid refrigerant flowing into the relay unit 102 from the indoor unit 103d are merged. Most of this merged liquid refrigerant flows into the bypass piping 20. The remaining part of this merged liquid refrigerant flows into the indoor unit 103a through the connecting piping 9b.
  • the liquid refrigerant that flows into the indoor unit 103a is decompressed and expanded by the load side throttling device 11a, becoming a low-temperature, low-pressure two-phase gas-liquid refrigerant, which flows into the load side heat exchanger 10a, which functions as an evaporator.
  • the low-temperature, low-pressure two-phase gas-liquid refrigerant that flows into the load side heat exchanger 10a absorbs heat from the indoor air, cooling the indoor air and becoming a low-temperature, low-pressure gas refrigerant.
  • the low-temperature, low-pressure gas refrigerant flowing out of the load-side heat exchanger 10a flows into the relay unit 102 via the connection pipe 9a and the second opening and closing device 32a.
  • This low-temperature, low-pressure gas refrigerant merges with the refrigerant flowing out of the bypass pipe 20 and becomes a two-phase gas-liquid refrigerant.
  • This two-phase gas-liquid refrigerant flows into the outdoor unit 101 through the fourth flow path 14d, the gas-liquid separator 17, and the first connection pipe 7.
  • the refrigerant that flows into the outdoor unit 101 passes through the heat source-side throttle device 5, and then becomes a low-temperature, low-pressure gas refrigerant while absorbing heat from the outdoor air in the heat source-side heat exchanger 3, and is sucked back into the compressor 1 via the heat source-side flow switching device 2.
  • the air conditioner 100 is a two-pipe simultaneous heating and cooling air conditioner in which the outdoor unit 101 and the relay unit 102 are connected by two connecting pipes.
  • a two-pipe simultaneous heating and cooling air conditioner there may be indoor units whose operation mode is the same before and after the refrigerant flow path in the outdoor unit is switched.
  • the air conditioning device 100 according to the first embodiment even if the refrigerant flow path in the outdoor unit 101 changes from FIG. 1 to FIG. 4, the open/close state of the opening/closing device 30a connected to the indoor unit 103a whose operation mode does not change remains the same. In this way, in the air conditioning device 100 according to the first embodiment, when the refrigerant flow path in the outdoor unit 101 is switched, the relay flow path switching device 14 can suppress the change in the open/close state of the opening/closing device 30 connected to the indoor unit 103.
  • the air conditioning device 100 when the refrigerant flow path in the outdoor unit 101 is switched, the air conditioning device 100 according to the first embodiment can suppress the occurrence of abnormal noise due to the change in the refrigerant flow, the decrease in the air conditioning capacity of the indoor unit 103 due to refrigerant pressure fluctuations, and the decrease in performance of the air conditioning device 100.
  • a conventional two-pipe simultaneous heating and cooling air conditioner has been proposed that is provided with a refrigerant flow control unit between the outdoor unit and the repeater, and that when the refrigerant flow path in the outdoor unit is switched, the open/close state of the opening/closing device connected to the indoor unit is suppressed from changing.
  • the refrigerant flow control unit and the repeater are connected by a high-pressure connection pipe through which a high-pressure refrigerant flows, and a low-pressure connection pipe through which a low-pressure refrigerant flows.
  • a conventional two-pipe simultaneous heating and cooling air conditioner that is intended to suppress changes in the open/close state of the opening/closing device connected to the indoor unit is configured such that, regardless of the refrigerant flow path in the outdoor unit, the refrigerant flows from the refrigerant flow control unit through the high-pressure connection pipe, and the refrigerant flows from the repeater to the refrigerant flow control unit through the low-pressure connection pipe.
  • Such conventional two-pipe simultaneous heating and cooling air conditioners have the following problems.
  • one of the two connecting pipes connecting the outdoor unit and the relay unit is configured so that liquid refrigerant or two-phase gas-liquid refrigerant flows, and gas refrigerant does not flow.
  • high-pressure gas refrigerant also flows in the high-pressure connecting pipe through which high-pressure liquid refrigerant flows.
  • the high-pressure connecting pipe used in a conventional two-pipe simultaneous heating and cooling operation air conditioner that has a refrigerant flow control unit has a larger diameter than the connecting pipe used in a conventional two-pipe simultaneous heating and cooling operation air conditioner that does not have a refrigerant flow control unit.
  • a conventional two-pipe simultaneous heating and cooling operation air conditioner that has a refrigerant flow control unit has a larger amount of refrigerant sealed in the air conditioner compared to a conventional two-pipe simultaneous heating and cooling operation air conditioner that does not have a refrigerant flow control unit.
  • the conventional two-pipe simultaneous cooling and heating air conditioner that suppresses the change in the open/close state of the opening/closing device connected to the indoor unit has a problem that the amount of refrigerant charged increases.
  • such a conventional two-pipe simultaneous cooling and heating air conditioner that is equipped with a refrigerant flow control unit may cause problems such as an increase in the installation space of the air conditioner, an increase in the manufacturing cost of the air conditioner, and an increase in the management cost of the air conditioner.
  • the air conditioning apparatus 100 as described above, of the two connecting pipes connecting the outdoor unit 101 and the relay unit 102, the first connecting pipe 7 through which liquid refrigerant or gas-liquid two-phase refrigerant flows is configured so that gas refrigerant does not flow. Therefore, the air conditioning apparatus 100 according to the first embodiment can prevent the diameter of the first connecting pipe 7 from becoming larger, and can also prevent an increase in the amount of refrigerant to be sealed.
  • the air conditioning apparatus 100 since the air conditioning apparatus 100 according to the first embodiment is provided with a relay flow path switching device 14 in the relay unit 102, it is possible to prevent the occurrence of problems such as an increase in the installation space for the air conditioning apparatus, an increase in the manufacturing cost of the air conditioning apparatus, and an increase in the management cost of the air conditioning apparatus.
  • the air conditioning device 100 includes an outdoor unit 101, a relay unit 102 connected to the outdoor unit 101 by a first connecting pipe 7 and a second connecting pipe 8, and a plurality of indoor units 103 connected to the relay unit 102 by connecting pipes 9a and 9b.
  • the outdoor unit 101 includes a compressor 1 that compresses and discharges a refrigerant, a heat source side heat exchanger 3 that exchanges heat between the outdoor air and the refrigerant, a heat source side throttle device 5 that is connected to the heat source side heat exchanger 3 and the first connecting pipe 7 and reduces the pressure of the refrigerant flowing between the heat source side heat exchanger 3 and the first connecting pipe 7, and a heat source side flow path switching device 2 that switches the flow path of the refrigerant flowing through the outdoor unit 101 between a first heat source side flow path 2a where the refrigerant flows out to the first connecting pipe 7 or a second heat source side flow path 2b where the refrigerant flows out to the second connecting pipe 8.
  • Each of the indoor units 103 includes a load-side heat exchanger 10 that exchanges heat between the load-side heat medium and the refrigerant, and a load-side throttle device 11 that is connected to the load-side heat exchanger 10 and reduces the pressure of the refrigerant to adjust the amount of refrigerant flowing to the load-side heat exchanger.
  • the relay unit 102 includes a plurality of opening/closing devices 30 and a relay flow path switching device 14. The opening/closing device 30 is connected to a connection port on the opposite side to the connection port to which the load-side throttle device 11 is connected in any of the load-side heat exchangers 10 of the plurality of indoor units 103.
  • Each of the opening/closing devices 30 has an outflow path through which the refrigerant flows from the relay unit 102 to the load-side heat exchanger 10, and an inflow path through which the refrigerant flows from the load-side heat exchanger 10 to the relay unit 102.
  • Each of the opening/closing devices 30 closes the inflow path when the outflow path is open, and opens the inflow path when the outflow path is closed.
  • the relay flow path switching device 14 is connected to each of the first connection pipe 7, the second connection pipe 8, and the opening and closing device 30.
  • this relay flow path switching device 14 switches the flow path of the relay flow path switching device 14, and is configured to make the open/closed state of the opening and closing device 30 connected to the indoor unit 103, which has the same operation mode before and after the flow path switching of the heat source side flow path switching device 2, the same before and after the flow path switching of the heat source side flow path switching device 2.
  • the air conditioning device 100 configured in this manner can suppress changes in the open/close state of the opening/closing device 30 connected to the indoor unit 103 by the relay flow path switching device 14 when the refrigerant flow path in the outdoor unit 101 is switched.
  • the air conditioning device 100 configured in this manner can also suppress an increase in the amount of refrigerant sealed in, as described above.
  • Embodiment 2 The bypass piping 21 and bypass opening and closing device 22 shown in the present embodiment 2 may be added to the configuration of the air conditioning apparatus 100 shown in the embodiment 1. Note that matters not specifically mentioned in the present embodiment 2 are the same as those in the embodiment 1. Also, in the present embodiment 2, components that perform the same functions as the components shown in the embodiment 1 are denoted by the same reference numerals as in the embodiment 1.
  • Fig. 5 is a refrigerant circuit diagram showing an example of a circuit configuration of an air conditioner according to embodiment 2 in a cooling only operation mode.
  • Fig. 6 is a refrigerant circuit diagram showing an example of a circuit configuration of an air conditioner according to embodiment 2 in a cooling main operation mode.
  • the air conditioning apparatus 100 according to the second embodiment includes a bypass piping 21 and a bypass opening/closing device 22 in addition to the configuration shown in the first embodiment.
  • the bypass piping 21 is a pipe that bypasses the second flow path 14b of the relay flow path switching device 14 and connects the second connection piping 8 to each of the inlet flow paths of the opening/closing device 30.
  • bypass piping 21 is a pipe that bypasses the second flow path 14b of the relay flow path switching device 14 and connects the second connection piping 8 to each of the second opening/closing devices 32 of the opening/closing device 30.
  • the bypass opening/closing device 22 is provided in the bypass piping 21 and opens and closes the flow path of the bypass piping 21.
  • This bypass opening and closing device 22 is configured to be in an open state when the heat source side flow path switching device 2 is in the first heat source side flow path 2a. That is, the bypass opening and closing device 22 is in an open state when the air conditioning device 100 is in a cooling only operation mode and a cooling-dominated operation mode. In other words, the bypass opening and closing device 22 is in a closed state when the air conditioning device 100 is in a heating only operation mode and a heating-dominated operation mode.
  • the flow of the refrigerant in the air conditioning device 100 according to the second embodiment is the same as in the first embodiment. For this reason, the following will explain the cooling only operation mode and the cooling-dominated operation mode executed by the air conditioning device 100 according to the second embodiment.
  • control device 6 switches the flow path of the heat source side flow path switching device 2 of the outdoor unit 101 to the first heat source side flow path 2a.
  • the control device 19 also controls the relay flow path switching device 14 to open the first flow path 14a and the second flow path 14b and close the third flow path 14c and the fourth flow path 14d.
  • the control device 19 also opens the bypass opening and closing device 22.
  • the compressor 1 When the compressor 1 is driven, it compresses low-temperature, low-pressure refrigerant and discharges it as high-temperature, high-pressure gas refrigerant.
  • the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 flows into the heat source side heat exchanger 3 via the heat source side flow switching device 2.
  • the high-temperature, high-pressure gas refrigerant that flows into the heat source side heat exchanger 3 then becomes high-pressure liquid refrigerant while releasing heat to the outdoor air.
  • the high-pressure liquid refrigerant that flows out of the heat source side heat exchanger 3 flows out of the outdoor unit 101, passes through the first connecting pipe 7, and flows into the relay unit 102.
  • the high-pressure liquid refrigerant that flows into the relay unit 102 passes through the gas-liquid separator 17, the relay unit throttling device 18, and the connecting pipe 9b, and flows into each indoor unit 103.
  • the high-pressure liquid refrigerant that flows into each indoor unit 103 is decompressed and expanded by the load-side throttling device 11, becoming a low-temperature, low-pressure, two-phase gas-liquid refrigerant.
  • This two-phase gas-liquid refrigerant flows into the load-side heat exchanger 10, which functions as an evaporator, and absorbs heat from the indoor air, cooling the indoor air and becoming a low-temperature, low-pressure gas refrigerant.
  • the merged low-temperature, low-pressure gas refrigerant flows out of the relay unit 102 and flows into the outdoor unit 101 again through the second connection pipe 8.
  • the low-temperature, low-pressure gas refrigerant flowing into the outdoor unit 101 passes through the heat source side flow path switching device 2 and is sucked back into the compressor 1.
  • the air conditioning device 100 according to the second embodiment has improved performance in the full cooling operation mode compared to the air conditioning device 100 shown in the first embodiment.
  • the cooling-dominated operation mode executed by the air-conditioning apparatus 100 will be described with reference to Fig. 6.
  • the cooling-dominated operation mode will be described using as an example a case in which the indoor units 103b, 103c, and 103d perform cooling operation and the indoor unit 103a performs heating operation.
  • control device 6 switches the flow path of the heat source side flow path switching device 2 of the outdoor unit 101 to the first heat source side flow path 2a.
  • the control device 19 also controls the relay flow path switching device 14 to open the first flow path 14a and the second flow path 14b and close the third flow path 14c and the fourth flow path 14d.
  • the control device 19 also opens the bypass opening/closing device 22.
  • the compressor 1 When the compressor 1 is driven, it compresses low-temperature, low-pressure refrigerant and discharges it as high-temperature, high-pressure gas refrigerant.
  • the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 flows into the heat source-side heat exchanger 3 via the heat source-side flow switching device 2.
  • the high-temperature, high-pressure gas refrigerant that flows into the heat source-side heat exchanger 3 becomes a high-pressure two-phase gas-liquid refrigerant while releasing heat to the outdoor air.
  • the high-pressure two-phase gas-liquid refrigerant that flows out of the heat source-side heat exchanger 3 flows out of the outdoor unit 101, passes through the first connecting pipe 7, and flows into the relay unit 102.
  • the high-pressure gas-liquid two-phase refrigerant that flows into the relay unit 102 is separated into high-pressure gas refrigerant and high-pressure liquid refrigerant by the gas-liquid separator 17.
  • This high-pressure gas refrigerant flows through the first flow path 14a of the relay flow path switching device 14, the first opening and closing device 31a, and the connection pipe 9a, before flowing into the indoor unit 103a.
  • the high-pressure gas refrigerant that flows into the indoor unit 103a then flows into the load side heat exchanger 10a, which functions as a condenser, and dissipates heat into the indoor air, turning into liquid refrigerant while heating the indoor air.
  • the liquid refrigerant flowing out of the load side heat exchanger 10a is depressurized and expanded in the load side throttling device 11a, and flows into the relay unit 102 through the connecting pipe 9b.
  • This refrigerant is separated in the gas-liquid separator 17, and then merges with the medium-pressure liquid refrigerant expanded to medium pressure in the relay unit throttling device 18.
  • This merged liquid refrigerant flows into the indoor units 103b, 103c, and 103d via the connecting pipe 9b.
  • the refrigerant that flows into the indoor unit 103b is depressurized and expanded by the load side throttling device 11b, becoming a two-phase gas-liquid refrigerant and flowing into the load side heat exchanger 10b, which functions as an evaporator.
  • the two-phase gas-liquid refrigerant that flows into the load side heat exchanger 10b absorbs heat from the indoor air, cooling the indoor air and becoming a low-temperature, low-pressure gas refrigerant.
  • the refrigerant that flows into the indoor unit 103c is depressurized and expanded by the load side throttling device 11c, becoming a two-phase gas-liquid refrigerant and flowing into the load side heat exchanger 10c, which functions as an evaporator.
  • the two-phase gas-liquid refrigerant that flows into the load side heat exchanger 10c absorbs heat from the indoor air, cooling the indoor air and becoming a low-temperature, low-pressure gas refrigerant.
  • the refrigerant that flows into the indoor unit 103d is depressurized and expanded by the load side throttling device 11d, becoming a two-phase gas-liquid refrigerant and flowing into the load side heat exchanger 10d, which functions as an evaporator.
  • the gas-liquid two-phase refrigerant that flows into the load-side heat exchanger 10d absorbs heat from the indoor air, cooling it and becoming a low-temperature, low-pressure gas refrigerant.
  • the low-temperature, low-pressure gas refrigerant flowing out of the load-side heat exchanger 10b flows into the second opening/closing device 32b through the connecting pipe 9a.
  • the low-temperature, low-pressure gas refrigerant flowing out of the load-side heat exchanger 10c flows into the second opening/closing device 32c through the connecting pipe 9a.
  • the low-temperature, low-pressure gas refrigerant flowing out of the load-side heat exchanger 10d flows into the second opening/closing device 32d through the connecting pipe 9a.
  • the low-temperature, low-pressure gas refrigerant flowing out of the second opening/closing device 32b, the low-temperature, low-pressure gas refrigerant flowing out of the second opening/closing device 32c, and the low-temperature, low-pressure gas refrigerant flowing out of the second opening/closing device 32d are then merged.
  • a portion of this merged low-temperature, low-pressure gas refrigerant flows into the second flow path 14b of the relay flow path switching device 14.
  • the remaining portion of this merged low-temperature, low-pressure gas refrigerant flows through the bypass pipe 21 and merges with the low-temperature, low-pressure gas refrigerant flowing out of the second flow path 14b.
  • this merged low-temperature, low-pressure gas refrigerant flows out of the relay unit 102 and flows through the second connection pipe 8 again into the outdoor unit 101.
  • the low-temperature, low-pressure gas refrigerant that flows into the outdoor unit 101 passes through the heat source side flow path switching device 2 and is sucked back into the compressor 1.
  • the pressure loss in the second flow path 14b of the relay flow path switching device 14 can be reduced. Therefore, the air conditioning device 100 according to the second embodiment has improved performance in the cooling-dominated operation mode compared to the air conditioning device 100 shown in the first embodiment.
  • Embodiment 3 In the air conditioning apparatus 100 shown in the first embodiment, when the heating only operation mode and the heating-dominated operation mode are executed, the relay throttling device 18 is in a closed state. However, as shown in the third embodiment, the relay throttling device 18 may be in an open state in the heating only operation mode and the heating-dominated operation mode. Note that matters not specifically mentioned in the third embodiment are the same as those in the first or second embodiment. In the third embodiment, the same reference numerals as those in the first or second embodiment are used for configurations that perform the same functions as those shown in the first or second embodiment.
  • Fig. 7 is a refrigerant circuit diagram showing an example of a circuit configuration of an air conditioner according to embodiment 3 in a heating only operation mode.
  • Fig. 8 is a refrigerant circuit diagram showing an example of a circuit configuration of an air conditioner according to embodiment 3 in a heating main operation mode.
  • the relay throttling device 18 when the full heating operation mode and the heating-dominant operation mode are executed, the relay throttling device 18 is in an open state. That is, in the air conditioning device 100 according to the third embodiment, the relay throttling device 18 is configured to be in an open state when the heat source side flow path switching device 2 is in the second heat source side flow path 2b.
  • the opening degree of the relay throttling device 18 at this time is not particularly limited.
  • the relay throttling device 18 may be fully open.
  • the opening degree of the relay throttling device 18 may be an intermediate opening degree between the fully closed state and the fully open state.
  • control device 6 switches the flow path of the heat source side flow path switching device 2 of the outdoor unit 101 to the second heat source side flow path 2b.
  • the control device 19 also controls the relay flow path switching device 14 to open the third flow path 14c and the fourth flow path 14d and close the first flow path 14a and the second flow path 14b.
  • the control device 19 also opens the relay unit throttle device 18.
  • the compressor 1 When the compressor 1 is driven, it compresses the low-temperature, low-pressure refrigerant and discharges it as high-temperature, high-pressure gas refrigerant.
  • the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 passes through the heat source side flow switching device 2 and flows out of the outdoor unit 101.
  • the high-temperature, high-pressure gas refrigerant flowing out of the outdoor unit 101 flows into the relay unit 102 through the second connection pipe 8.
  • the high-temperature, high-pressure gas refrigerant that flows into the relay unit 102 flows into each indoor unit 103 via the third flow path 14c of the relay flow path switching device 14, the first opening and closing device 31 connected to each indoor unit 103, and the connecting pipe 9a.
  • the high-temperature, high-pressure gas refrigerant that flows into each indoor unit 103 flows into the load side heat exchanger 10, which functions as a condenser.
  • the refrigerant that flows into the load side heat exchanger 10 becomes liquid refrigerant by dissipating heat to the indoor air, heating the indoor air.
  • the liquid refrigerant that flows out of the load side heat exchanger 10 is decompressed and expanded by the load side throttle device 11, becoming a low-temperature, low-pressure gas-liquid two-phase refrigerant, which flows into the relay unit 102 through the connecting pipe 9b.
  • the low-temperature, low-pressure, two-phase gas-liquid refrigerant flowing from each indoor unit 103 to the relay unit 102 merges and then flows into the bypass piping 20.
  • the low-temperature, low-pressure, two-phase gas-liquid refrigerant flowing out of the bypass piping 20 flows into the outdoor unit 101 after passing through the gas-liquid separator 17.
  • refrigeration oil flowing out from the compressor 1 accumulates in the gas-liquid separator 17.
  • the low-temperature, low-pressure, two-phase gas-liquid refrigerant that flows into the bypass piping 20 flows through the fourth flow path 14d of the relay flow path switching device 14, the gas-liquid separator 17, and the first connection piping 7, and then flows into the outdoor unit 101.
  • the low-temperature, low-pressure, two-phase gas-liquid refrigerant becomes a low-temperature, low-pressure gas refrigerant while absorbing heat from the outdoor air in the heat source side heat exchanger 3, and is sucked back into the compressor 1 via the heat source side flow path switching device 2.
  • Heating-dominant operation mode The heating-dominated operation mode executed by the air conditioning apparatus 100 will be described with reference to Fig. 8.
  • the heating-dominated operation mode will be described using as an example a case in which the indoor units 103b, 103c, and 103d perform heating operation and the indoor unit 103a performs cooling operation.
  • control device 6 switches the flow path of the heat source side flow path switching device 2 of the outdoor unit 101 to the second heat source side flow path 2b.
  • the control device 19 also controls the relay flow path switching device 14 to open the third flow path 14c and the fourth flow path 14d and close the first flow path 14a and the second flow path 14b.
  • the control device 19 also opens the relay unit throttle device 18.
  • the compressor 1 When the compressor 1 is driven, it compresses the low-temperature, low-pressure refrigerant and discharges it as high-temperature, high-pressure gas refrigerant.
  • the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 passes through the heat source side flow switching device 2 and flows out of the outdoor unit 101.
  • the high-temperature, high-pressure gas refrigerant flowing out of the outdoor unit 101 flows into the relay unit 102 through the second connection pipe 8.
  • the high-temperature, high-pressure gas refrigerant that flows into the relay unit 102 flows through the third flow path 14c of the relay flow path switching device 14 into the first opening/closing device 31b, the first opening/closing device 31c, and the first opening/closing device 31b.
  • the high-temperature, high-pressure gas refrigerant that flows into the first opening/closing device 31b flows through the connecting pipe 9a into the indoor unit 103b.
  • the high-temperature, high-pressure gas refrigerant that flows into the first opening/closing device 31c flows through the connecting pipe 9a into the indoor unit 103c.
  • the high-temperature, high-pressure gas refrigerant that flows into the first opening/closing device 31d flows through the connecting pipe 9a into the indoor unit 103d.
  • the high-temperature, high-pressure gas refrigerant that flows into the indoor unit 103b flows into the load-side heat exchanger 10b, which functions as a condenser.
  • the high-temperature, high-pressure gas refrigerant that flows into the load-side heat exchanger 10b dissipates heat to the indoor air, turning into liquid refrigerant while heating the indoor air.
  • the liquid refrigerant that flows out of the load-side heat exchanger 10b is depressurized and expanded by the load-side throttling device 11b, and flows into the repeater 102 via the connecting pipe 9b.
  • the high-temperature, high-pressure gas refrigerant that flows into the indoor unit 103c flows into the load-side heat exchanger 10c, which functions as a condenser.
  • the high-temperature, high-pressure gas refrigerant that flows into the load-side heat exchanger 10c dissipates heat to the indoor air, turning into liquid refrigerant while heating the indoor air.
  • the liquid refrigerant that flows out of the load-side heat exchanger 10c is depressurized and expanded by the load-side throttling device 11c, and flows into the repeater 102 via the connecting pipe 9b.
  • the high-temperature, high-pressure gas refrigerant that flows into the indoor unit 103d flows into the load-side heat exchanger 10d, which functions as a condenser.
  • the high-temperature, high-pressure gas refrigerant that flows into the load-side heat exchanger 10d dissipates heat into the indoor air, heating the indoor air and becoming liquid refrigerant.
  • the liquid refrigerant that flows out of the load-side heat exchanger 10d is depressurized and expanded by the load-side throttle device 11d, and flows into the relay unit 102 via the connection pipe 9b.
  • the liquid refrigerant flowing from the indoor unit 103b to the relay unit 102, the liquid refrigerant flowing from the indoor unit 103c to the relay unit 102, and the liquid refrigerant flowing from the indoor unit 103d to the relay unit 102 are merged. Most of this merged liquid refrigerant flows into the bypass piping 20. The remaining part of this merged liquid refrigerant flows through the connection piping 9b and into the indoor unit 103a.
  • the relay throttling device 18 is in the open state, so refrigeration oil flows out of the gas-liquid separator 17 and merges with the liquid refrigerant flowing into the bypass piping 20. Therefore, the air conditioning device 100 according to the third embodiment can suppress the accumulation of refrigeration oil in the gas-liquid separator 17.
  • the liquid refrigerant that flows into the indoor unit 103a is decompressed and expanded by the load-side throttling device 11a, becoming a low-temperature, low-pressure, two-phase gas-liquid refrigerant, which flows into the load-side heat exchanger 10a, which functions as an evaporator.
  • the low-temperature, low-pressure, two-phase gas-liquid refrigerant that flows into the load-side heat exchanger 10a absorbs heat from the indoor air, cooling the indoor air and becoming a low-temperature, low-pressure gas refrigerant.
  • the low-temperature, low-pressure gas refrigerant that flows out of the load-side heat exchanger 10a flows into the relay unit 102 via the connection pipe 9a and the second opening and closing device 32a.
  • This low-temperature, low-pressure gas refrigerant merges with the refrigerant that flows out of the bypass pipe 20 and becomes a two-phase gas-liquid refrigerant.
  • This two-phase gas-liquid refrigerant flows into the outdoor unit 101 through the fourth flow path 14d, the gas-liquid separator 17, and the first connection pipe 7.
  • the refrigerant that flows into the outdoor unit 101 passes through the heat source side throttle device 5, and then becomes a low-temperature, low-pressure gas refrigerant while absorbing heat from the outdoor air in the heat source side heat exchanger 3, and is sucked back into the compressor 1 via the heat source side flow switching device 2.
  • Embodiment 4 The position of the gas-liquid separator 17 in the relay unit 102 is not limited to the position shown in the first to third embodiments.
  • the gas-liquid separator 17 may be arranged in the relay unit 102 at the position shown in the fourth embodiment, for example. Note that matters not specifically mentioned in the fourth embodiment are the same as those in the first to third embodiments.
  • the same reference numerals as those in the first to third embodiments are used for configurations that perform the same functions as those in the first to third embodiments.
  • Fig. 9 is a refrigerant circuit diagram showing an example of a circuit configuration of an air conditioner according to embodiment 4 in a heating only operation mode.
  • Fig. 10 is a refrigerant circuit diagram showing an example of a circuit configuration of an air conditioner according to embodiment 4 in a heating main operation mode.
  • the first flow path 14a is connected to the first connection pipe 7 and the inlet 17a of the gas-liquid two-phase refrigerant of the gas-liquid separator 17.
  • the third flow path 14c is connected to the second connection pipe 8 and the inlet 17a of the gas-liquid two-phase refrigerant of the gas-liquid separator 17.
  • the outlet 17b of the gas-liquid separator 17 for the gas refrigerant is directly connected to the outflow flow path of the opening and closing device 30. That is, the outlet 17b of the gas-liquid separator 17 for the gas refrigerant is directly connected to the first opening and closing device 31 of the opening and closing device 30.
  • the operation of the air conditioning apparatus 100 according to the fourth embodiment when executing the heating only operation mode and the heating main operation mode will be described.
  • control device 6 switches the flow path of the heat source side flow path switching device 2 of the outdoor unit 101 to the second heat source side flow path 2b.
  • control device 19 controls the relay flow path switching device 14 to open the third flow path 14c and the fourth flow path 14d and close the first flow path 14a and the second flow path 14b.
  • the compressor 1 When the compressor 1 is driven, it compresses the low-temperature, low-pressure refrigerant and discharges it as high-temperature, high-pressure gas refrigerant.
  • the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 passes through the heat source side flow switching device 2 and flows out of the outdoor unit 101.
  • the high-temperature, high-pressure gas refrigerant flowing out of the outdoor unit 101 flows into the relay unit 102 through the second connection pipe 8.
  • the high-temperature, high-pressure gas refrigerant that flows into the relay unit 102 flows into each indoor unit 103 via the third flow path 14c of the relay flow path switching device 14, the gas-liquid separator 17, the first opening and closing device 31 connected to each indoor unit 103, and the connecting pipe 9a.
  • the high-temperature, high-pressure gas refrigerant that flows into each indoor unit 103 flows into the load side heat exchanger 10 that functions as a condenser.
  • the refrigerant that flows into the load side heat exchanger 10 becomes liquid refrigerant by releasing heat to the indoor air, heating the indoor air.
  • the liquid refrigerant that flows out of the load side heat exchanger 10 is decompressed and expanded by the load side throttle device 11, becoming a low-temperature, low-pressure gas-liquid two-phase refrigerant, which flows into the relay unit 102 through the connecting pipe 9b.
  • the air conditioning device 100 according to this embodiment 4 can suppress the accumulation of refrigeration oil in the gas-liquid separator 17.
  • the low-temperature, low-pressure, gas-liquid two-phase refrigerant that flows into the outdoor unit 101 passes through the heat source side throttle device 5, and then becomes a low-temperature, low-pressure gas refrigerant while absorbing heat from the outdoor air in the heat source side heat exchanger 3, and is sucked back into the compressor 1 via the heat source side flow switching device 2.
  • Heating-dominant operation mode The heating-dominated operation mode executed by the air conditioning apparatus 100 will be described with reference to Fig. 10.
  • the heating-dominated operation mode will be described using as an example a case in which the indoor units 103b, 103c, and 103d perform heating operation and the indoor unit 103a performs cooling operation.
  • control device 6 switches the flow path of the heat source side flow path switching device 2 of the outdoor unit 101 to the second heat source side flow path 2b.
  • control device 19 controls the relay flow path switching device 14 to open the third flow path 14c and the fourth flow path 14d and close the first flow path 14a and the second flow path 14b.
  • the compressor 1 When the compressor 1 is driven, it compresses the low-temperature, low-pressure refrigerant and discharges it as high-temperature, high-pressure gas refrigerant.
  • the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 passes through the heat source side flow switching device 2 and flows out of the outdoor unit 101.
  • the high-temperature, high-pressure gas refrigerant flowing out of the outdoor unit 101 flows into the relay unit 102 through the second connection pipe 8.
  • the high-temperature, high-pressure gas refrigerant that flows into the relay unit 102 flows through the third flow path 14c of the relay flow path switching device 14 and the gas-liquid separator 17, and then flows into the first opening/closing device 31b, the first opening/closing device 31c, and the first opening/closing device 31b.
  • the high-temperature, high-pressure gas refrigerant that flows into the first opening/closing device 31b flows into the indoor unit 103b through the connecting pipe 9a.
  • the high-temperature, high-pressure gas refrigerant that flows into the first opening/closing device 31c flows into the indoor unit 103c through the connecting pipe 9a.
  • the high-temperature, high-pressure gas refrigerant that flows into the first opening/closing device 31d flows into the indoor unit 103d through the connecting pipe 9a.
  • the high-temperature, high-pressure gas refrigerant that flows into the indoor unit 103b flows into the load-side heat exchanger 10b, which functions as a condenser.
  • the high-temperature, high-pressure gas refrigerant that flows into the load-side heat exchanger 10b dissipates heat to the indoor air, turning into liquid refrigerant while heating the indoor air.
  • the liquid refrigerant that flows out of the load-side heat exchanger 10b is depressurized and expanded by the load-side throttling device 11b, and flows into the repeater 102 via the connecting pipe 9b.
  • the high-temperature, high-pressure gas refrigerant that flows into the indoor unit 103c flows into the load-side heat exchanger 10c, which functions as a condenser.
  • the high-temperature, high-pressure gas refrigerant that flows into the load-side heat exchanger 10c dissipates heat to the indoor air, turning into liquid refrigerant while heating the indoor air.
  • the liquid refrigerant that flows out of the load-side heat exchanger 10c is depressurized and expanded by the load-side throttling device 11c, and flows into the repeater 102 via the connecting pipe 9b.
  • the high-temperature, high-pressure gas refrigerant that flows into the indoor unit 103d flows into the load-side heat exchanger 10d, which functions as a condenser.
  • the high-temperature, high-pressure gas refrigerant that flows into the load-side heat exchanger 10d dissipates heat into the indoor air, heating the indoor air and becoming liquid refrigerant.
  • the liquid refrigerant that flows out of the load-side heat exchanger 10d is depressurized and expanded by the load-side throttle device 11d, and flows into the relay unit 102 via the connection pipe 9b.
  • the liquid refrigerant flowing into the relay unit 102 from the indoor unit 103b, the liquid refrigerant flowing into the relay unit 102 from the indoor unit 103c, and the liquid refrigerant flowing into the relay unit 102 from the indoor unit 103d are merged. Most of this merged liquid refrigerant flows into the bypass piping 20. The remaining part of this merged liquid refrigerant flows into the indoor unit 103a through the connecting piping 9b.
  • the liquid refrigerant that flows into the indoor unit 103a is decompressed and expanded by the load side throttling device 11a, becoming a low-temperature, low-pressure two-phase gas-liquid refrigerant, which flows into the load side heat exchanger 10a, which functions as an evaporator.
  • the low-temperature, low-pressure two-phase gas-liquid refrigerant that flows into the load side heat exchanger 10a absorbs heat from the indoor air, cooling the indoor air and becoming a low-temperature, low-pressure gas refrigerant.
  • the low-temperature, low-pressure gas refrigerant flowing out from the load-side heat exchanger 10a flows into the relay unit 102 via the connection pipe 9a and the second opening and closing device 32a.
  • This low-temperature, low-pressure gas refrigerant merges with the refrigerant flowing out from the bypass pipe 20 to become a two-phase gas-liquid refrigerant.
  • This two-phase gas-liquid refrigerant flows into the outdoor unit 101 through the fourth flow path 14d and the first connection pipe 7.
  • the air conditioning device 100 can suppress the accumulation of refrigeration oil in the gas-liquid separator 17.
  • the refrigerant that flows into the outdoor unit 101 passes through the heat source side throttle device 5, and then becomes a low-temperature, low-pressure gas refrigerant while absorbing heat from the outdoor air in the heat source side heat exchanger 3, and is sucked back into the compressor 1 via the heat source side flow switching device 2.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Compression-Type Refrigeration Machines With Reversible Cycles (AREA)
PCT/JP2023/012806 2023-03-29 2023-03-29 空気調和装置 WO2024201778A1 (ja)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0351672A (ja) * 1989-07-19 1991-03-06 Mitsubishi Electric Corp 空気調和装置
JP5877632B2 (ja) * 2010-06-07 2016-03-08 三菱電機株式会社 空気調和装置
WO2017183308A1 (ja) * 2016-04-19 2017-10-26 日立ジョンソンコントロールズ空調株式会社 空気調和機
WO2022224390A1 (ja) * 2021-04-22 2022-10-27 三菱電機株式会社 冷凍サイクル装置

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0351672A (ja) * 1989-07-19 1991-03-06 Mitsubishi Electric Corp 空気調和装置
JP5877632B2 (ja) * 2010-06-07 2016-03-08 三菱電機株式会社 空気調和装置
WO2017183308A1 (ja) * 2016-04-19 2017-10-26 日立ジョンソンコントロールズ空調株式会社 空気調和機
WO2022224390A1 (ja) * 2021-04-22 2022-10-27 三菱電機株式会社 冷凍サイクル装置

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