WO2021192195A1 - Air conditioner - Google Patents

Air conditioner Download PDF

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Publication number
WO2021192195A1
WO2021192195A1 PCT/JP2020/013900 JP2020013900W WO2021192195A1 WO 2021192195 A1 WO2021192195 A1 WO 2021192195A1 JP 2020013900 W JP2020013900 W JP 2020013900W WO 2021192195 A1 WO2021192195 A1 WO 2021192195A1
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WO
WIPO (PCT)
Prior art keywords
valve
heat exchanger
refrigerant
temperature
cooling operation
Prior art date
Application number
PCT/JP2020/013900
Other languages
French (fr)
Japanese (ja)
Inventor
田中　健司
牧野　浩招
Original Assignee
三菱電機株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to JP2022510303A priority Critical patent/JP7241967B2/en
Priority to PCT/JP2020/013900 priority patent/WO2021192195A1/en
Publication of WO2021192195A1 publication Critical patent/WO2021192195A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F1/00—Room units for air-conditioning, e.g. separate or self-contained units or units receiving primary air from a central station
    • F24F1/0003—Room units for air-conditioning, e.g. separate or self-contained units or units receiving primary air from a central station characterised by a split arrangement, wherein parts of the air-conditioning system, e.g. evaporator and condenser, are in separately located units
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/70—Control systems characterised by their outputs; Constructional details thereof
    • F24F11/80—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air
    • F24F11/83—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers
    • F24F11/84—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers using valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B13/00—Compression machines, plants or systems, with reversible cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
    • F25B41/24—Arrangement of shut-off valves for disconnecting a part of the refrigerant cycle, e.g. an outdoor part
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
    • F25B2313/031—Sensor arrangements
    • F25B2313/0313—Pressure sensors near the outdoor heat exchanger
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
    • F25B2313/031—Sensor arrangements
    • F25B2313/0314—Temperature sensors near the indoor heat exchanger
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
    • F25B2313/031—Sensor arrangements
    • F25B2313/0315—Temperature sensors near the outdoor heat exchanger
    • 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
    • F25B2347/00—Details for preventing or removing deposits or corrosion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2500/00—Problems to be solved
    • F25B2500/19—Calculation of parameters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2500/00—Problems to be solved
    • F25B2500/26—Problems to be solved characterised by the startup of the refrigeration cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2500/00—Problems to be solved
    • F25B2500/31—Low ambient temperatures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/02—Compressor control
    • F25B2600/025—Compressor control by controlling speed
    • F25B2600/0251—Compressor control by controlling speed with on-off operation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/02—Compressor control
    • F25B2600/025—Compressor control by controlling speed
    • F25B2600/0253—Compressor control by controlling speed with variable speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/23—Time delays
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/25—Control of valves
    • F25B2600/2507—Flow-diverting valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/25—Control of valves
    • F25B2600/2513—Expansion valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/25—Control of valves
    • F25B2600/2519—On-off valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2104—Temperatures of an indoor room or compartment
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2106—Temperatures of fresh outdoor air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2116—Temperatures of a condenser
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2117—Temperatures of an evaporator
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Definitions

  • This disclosure relates to an air conditioner, particularly to a cooling operation at a low outside air temperature.
  • an air conditioner has a refrigerant circuit in which a compressor, a condenser, an expansion valve, and an evaporator are connected by a refrigerant pipe.
  • the air conditioner is installed in a machine room in which a heat-generating device such as a computer or a telephone exchange is installed, and performs a cooling operation to suppress an increase in the room temperature of the machine room due to the heat generated by the device.
  • Air conditioners installed in machine rooms, etc. need to be cooled regardless of the season. However, in a low outside air environment where the outside air temperature is below freezing, the refrigerant existing in the outdoor unit is cooled by the outside air while the operation of the air conditioner is stopped, and accumulates in equipment such as the compressor and condenser mounted on the outdoor unit.
  • Some conventional air conditioners have a configuration that prevents the refrigerant from accumulating in the compressor, that is, the refrigerant from falling asleep when the operation is stopped (see, for example, Patent Document 1).
  • Patent Document 1 a parallel circuit including a refrigerant cylinder is provided in parallel with the refrigerant pipe on the outdoor unit side of the refrigerant pipes connecting the condenser and the evaporator, and two solenoid valves are provided before and after the refrigerant cylinder in the parallel circuit. Is disclosed to be provided.
  • an air conditioner is configured to perform antifreezing control to stop the compressor when the temperature of the evaporator becomes lower than the set temperature in order to prevent the condensed water generated in the evaporator of the indoor unit from freezing during the cooling operation. Has been done.
  • the present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide an air conditioner capable of performing a steady cooling operation in a cooling operation in a low outside air environment.
  • the air conditioner according to the present disclosure is an air conditioner in which an indoor unit installed in an air-conditioned space and an outdoor unit are connected, and is a compressor, a flow path switching valve, an outdoor heat exchanger, and an expansion valve.
  • the indoor heat exchanger are provided in the refrigerant circuit connected by the refrigerant pipe, and in the refrigerant circuit between one of the inlet / outlet of the indoor heat exchanger and the flow path switching valve, and arranged in the indoor unit. It is provided with a first on-off valve provided, and a second on-off valve provided between the other of the inlet and outlet of the indoor heat exchanger and the expansion valve in the refrigerant circuit and arranged in the indoor unit.
  • the refrigerant can be stored in the indoor unit by using these on-off valves, and the operation can be performed even in a low outside air environment. It suppresses the decrease in the refrigerant temperature due to the outside air temperature during stoppage, and enables steady operation when the cooling operation is restarted.
  • FIG. It is the schematic which shows an example of the refrigerant circuit of the air conditioner which concerns on Embodiment 1.
  • FIG. It is a functional block diagram which shows the function of the control device described in FIG. It is a flowchart of the control performed by the control device when the cooling operation is stopped in low outside air. It is a figure which shows the operation of each device in the 1st control. It is explanatory drawing which shows the refrigerant flow of the refrigerant circuit at the time of performing the storage process of the 1st control. It is a refrigerant circuit diagram which shows the state which the refrigerant is sealed in the indoor unit after the completion of the storage process of FIG.
  • FIG. 1 is a schematic view showing an example of a refrigerant circuit of the air conditioner according to the first embodiment.
  • the air conditioner 100 includes an indoor unit 20 installed in a room (indoor) which is an air-conditioned space, and an outdoor unit 10 connected to the indoor unit 20 and installed outdoors (outdoors), for example. Further, the air conditioner 100 includes a control device 50 that controls the operation of the air conditioner 100 by controlling each device constituting the outdoor unit 10 and the indoor unit 20.
  • the indoor unit 20 includes an indoor heat exchanger 5.
  • the outdoor unit 10 includes a compressor 1, a flow path switching valve 2, an outdoor heat exchanger 3, an expansion valve 4, and the like. These compressor 1, flow path switching valve 2, outdoor heat exchanger 3, expansion valve 4, and indoor heat exchanger 5 are connected in an annular shape via a refrigerant pipe to form a refrigerant circuit 100a.
  • the refrigerant circuit 100a is filled with a refrigerant.
  • the type of refrigerant is not particularly limited.
  • the outdoor unit 10 and the indoor unit 20 are connected by two connecting pipes 7 and 8.
  • the connection pipe 7 connects the outdoor unit 10 and the indoor unit 20 between the expansion valve 4 and the indoor heat exchanger 5, and a gas refrigerant flows through the connection pipe 7.
  • the connection pipe 8 connects the outdoor unit 10 and the indoor unit 20 between the indoor heat exchanger 5 and the flow path switching valve 2, and a liquid refrigerant flows through the connection pipe 8.
  • the indoor unit 20 includes an indoor pipe 28 that connects one of the refrigerant inlets and outlets of the indoor heat exchanger 5 and the connection pipe 8, and an indoor pipe 27 that connects the other of the refrigerant inlets and outlets of the indoor heat exchanger 5 and the connection pipe 7. Has.
  • the compressor 1 compresses the refrigerant, discharges it, and circulates it.
  • the compressor 1 is configured to include a compression mechanism for compressing the refrigerant and a compressor motor for operating the compression mechanism inside a shell which is an outer shell.
  • the compressor motor is a three-phase motor having three-phase motor windings of U-phase, V-phase and W-phase. A voltage is applied to the compressor motor by an inverter (not shown).
  • the flow path switching valve 2 is composed of, for example, a four-way valve, and switches the flow path of the refrigerant circuit 100a between the cooling operation and the heating operation of the air conditioner 100 to switch the flow direction of the refrigerant.
  • the discharge side of the compressor 1 is connected to the outdoor heat exchanger 3, and in the heating operation, the suction side of the compressor 1 is connected to the outdoor heat exchanger 3.
  • FIG. 1 shows a connection state of the flow path switching valve 2 when the air conditioner 100 is in the cooling operation.
  • the flow path switching valve 2 may have a configuration in which a three-way switching valve, a two-way switching valve, or the like is combined.
  • the outdoor heat exchanger 3 exchanges heat between the refrigerant and the outside air, and is composed of, for example, a fin-and-tube heat exchanger having a plurality of fins and a plurality of heat transfer tubes.
  • the outdoor heat exchanger 3 acts as a condenser, and when the air conditioner 100 is in the heating operation, the outdoor heat exchanger 3 acts as an evaporator.
  • the expansion valve 4 decompresses and expands the refrigerant.
  • the indoor heat exchanger 5 exchanges heat between the refrigerant and the indoor air, and is composed of, for example, a fin-and-tube heat exchanger having a plurality of fins and a plurality of heat transfer tubes.
  • the indoor heat exchanger 5 acts as an evaporator, and when the air conditioner 100 is in the heating operation, the indoor heat exchanger 5 acts as a condenser.
  • the indoor unit 20 further includes an indoor fan 21 that blows air to the indoor heat exchanger 5.
  • the outdoor unit 10 further includes an outdoor fan 11 that blows air to the outdoor heat exchanger 3.
  • the indoor unit 20 has two on-off valves (first on-off valve 31 and second on-off valve 32) capable of storing the refrigerant in the indoor unit 20.
  • the first on-off valve 31 and the second on-off valve 32 are each composed of, for example, an electromagnetic on-off valve.
  • the first on-off valve 31 is provided in the indoor pipe 28 through which the gas refrigerant flows, and the second on-off valve 32 is provided in the indoor pipe 27 in which the liquid refrigerant flows.
  • the air conditioner 100 is provided with a plurality of sensors. Specifically, a second sensor 42 for detecting the room temperature of the room which is the space to be air-conditioned and a fourth sensor 44 for detecting the temperature of the indoor heat exchanger 5 are provided.
  • the second sensor 42 is composed of, for example, a temperature sensor, and is arranged in the vicinity of a suction port provided in a housing (not shown) of the indoor unit 20.
  • the fourth sensor 44 is composed of, for example, a temperature sensor, and is arranged in the heat transfer tube of the indoor heat exchanger 5 to detect the surface temperature of the heat transfer tube.
  • the fourth sensor 44 may be installed at a position in the middle of the heat transfer tube connecting the refrigerant inlet / outlet in the indoor heat exchanger 5.
  • the outdoor unit 10 is provided with a first sensor 41 for detecting the outside air temperature and a third sensor 43 for detecting the temperature of the outdoor heat exchanger 3.
  • the first sensor 41 is composed of, for example, a temperature sensor.
  • the third sensor 43 is composed of, for example, a temperature sensor, and is arranged in the heat transfer tube of the outdoor heat exchanger 3 to detect the surface temperature of the heat transfer tube. In particular, the third sensor 43 may be installed at a position intermediate between the heat transfer tubes connecting the two entrances and exits of the outdoor heat exchanger 3.
  • the third sensor 43 is composed of a pressure sensor and a control device 50.
  • the pressure sensor detects the refrigerant pressure in the heat transfer tube of the outdoor heat exchanger 3, and the detected refrigerant pressure of the outdoor heat exchanger 3 is used.
  • the control device 50 may calculate the temperature. Alternatively, when the compressor 1 or the like is controlled by using the condensation temperature during operation, a sensor that detects the condensation temperature can be used as the third sensor 43.
  • the control device 50 is composed of dedicated hardware or a CPU (Central Processing Unit) that executes a program stored in a memory.
  • the CPU is also referred to as a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, or a processor.
  • control device 50 When the control device 50 is dedicated hardware, the control device 50 may be, for example, a single circuit, a composite circuit, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof. Applicable. Each of the functional units realized by the control device 50 may be realized by individual hardware, or each functional unit may be realized by one hardware.
  • ASIC Application Specific Integrated Circuit
  • FPGA Field-Programmable Gate Array
  • each function executed by the control device 50 is 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 each function of the control device 50 by reading and executing the program stored in the memory.
  • the memory is a non-volatile or volatile semiconductor memory such as RAM, ROM, flash memory, EPROM, or EEPROM.
  • a part of the function of the control device 50 may be realized by dedicated hardware, and a part may be realized by software or firmware.
  • the control device 50 is electrically connected to each of a plurality of sensors including the first sensor 41, the second sensor 42, the third sensor 43, and the fourth sensor 44, and the control device 50 detects the plurality of sensors. Information is entered. Further, from a remote controller (not shown), the start and stop of the cooling operation, the start and stop of the heating operation, the set temperature during the cooling operation, the set temperature during the heating operation, and the like are input to the control device 50. The control device 50 controls the operation of each device constituting the outdoor unit 10 and the indoor unit 20 based on the input information.
  • FIG. 2 is a functional block diagram showing the functions of the control device shown in FIG.
  • the control device 50 includes an input unit 51, a main control unit 52, and a storage unit 53 as functional units.
  • the detection information of a plurality of sensors, the information via the remote controller, and the like are input to the input unit 51.
  • the storage unit 53 stores the information input to the input unit 51, the set value used by the main control unit 52 to control each device, the control target value, and the like.
  • the main control unit 52 Based on the information input to the input unit 51, the main control unit 52 switches the frequency of the compressor 1, the flow path switching valve 2, the opening degree of the expansion valve 4, the rotation speed of the outdoor fan 11, and the indoor fan 21. Controls the number of rotations, etc.
  • the main control unit 52 controls the operations of the first on-off valve 31 and the second on-off valve 32 based on the information input to the input unit 51. Specifically, the main control unit 52 fully opens the first on-off valve 31 and the second on-off valve 32 during the cooling operation and the heating operation.
  • the air conditioner 100 prevents the dew condensation water generated on the surface of the heat transfer tube of the indoor heat exchanger 5 from freezing when the temperature of the indoor heat exchanger 5 is equal to or lower than the set temperature during the cooling operation. It has a function. Specifically, the main control unit 52 sets the compressor 1 when the temperature of the indoor heat exchanger 5 detected by the fourth sensor 44 becomes, for example, 3 ° C. or lower during the cooling operation of the air conditioner 100. Controls to stop the operation. With such anti-freezing control, it is possible to prevent the indoor heat exchanger 5 from freezing and prevent damage to the equipment due to freezing.
  • the main control unit 52 performs a refrigerant storage process and a compressor according to the detection information of the first sensor 41, the second sensor 42, and the third sensor 43.
  • the first control including the preheating of 1 is performed.
  • the first on-off valve 31, the second on-off valve 32, the flow path switching valve 2, and the compressor 1 are controlled to perform predetermined operations. The first control will be described later.
  • the main control unit 52 responds to the detection information of the first sensor 41, the second sensor 42, and the third sensor 43. , Performs a second control including the release process of the refrigerant. Specifically, in the second control, the first on-off valve 31, the second on-off valve 32, the expansion valve 4, the compressor 1, and the outdoor fan 11 are controlled to perform predetermined operations. The second control will be described later.
  • the flow path switching valve 2 is in the connected state shown by the solid line in FIG. In FIG. 1, the direction of the refrigerant flow during the cooling operation is indicated by a solid arrow.
  • the refrigerant is compressed by the compressor 1 to a high temperature and high pressure, and flows into the outdoor heat exchanger 3 via the flow path switching valve 2.
  • the refrigerant that has flowed into the outdoor heat exchanger 3 is condensed and liquefied by dissipating heat from the surrounding air, that is, the outside air in the outdoor heat exchanger 3.
  • the drive of the outdoor fan 11 promotes heat exchange between the refrigerant and the outside air.
  • the refrigerant flowing out of the outdoor heat exchanger 3 is decompressed by the expansion valve 4 to expand, and enters the indoor unit 20 through the connecting pipe 7.
  • the refrigerant that has entered the indoor unit 20 flows into the indoor heat exchanger 5 through the second on-off valve 32 that is fully opened.
  • the refrigerant flowing into the indoor heat exchanger 5 evaporates and gasifies by absorbing heat from the surrounding air, that is, the indoor air in the indoor heat exchanger 5.
  • the drive of the indoor fan 21 promotes heat exchange between the refrigerant and the indoor air.
  • the refrigerant flowing out of the indoor heat exchanger 5 flows out from the indoor unit 20 through the first on-off valve 31 which is fully opened, and flows into the outdoor unit 10 through the connection pipe 8.
  • the refrigerant that has flowed into the outdoor unit 10 is sucked into the compressor 1 again via the flow path switching valve 2 and compressed. During the cooling operation, the above cycle is repeated to cool the room.
  • the flow path switching valve 2 is in the connected state shown by the broken line in FIG.
  • the refrigerant is compressed by the compressor 1 to a high temperature and high pressure, and flows out from the outdoor unit 10 via the flow path switching valve 2.
  • the refrigerant flowing out of the outdoor unit 10 flows into the indoor unit 20 through the connecting pipe 8 and flows into the indoor heat exchanger 5 through the first on-off valve 31 which is fully opened.
  • the refrigerant flowing into the indoor heat exchanger 5 is condensed and liquefied by radiating heat to the surrounding air, that is, the indoor air in the indoor heat exchanger 5.
  • the drive of the indoor fan 21 promotes heat exchange between the refrigerant and the air.
  • the refrigerant flowing out of the indoor heat exchanger 5 flows out from the indoor unit 20 through the second on-off valve 32 which is fully opened.
  • the refrigerant flowing out of the indoor unit 20 flows into the outdoor unit 10 through the connecting pipe 7, is decompressed by the expansion valve 4, expands, and flows into the outdoor heat exchanger 3.
  • the refrigerant flowing into the outdoor heat exchanger 3 evaporates and gasifies by absorbing heat from the surrounding air, that is, the outside air in the outdoor heat exchanger 3.
  • the drive of the outdoor fan 11 promotes heat exchange between the refrigerant and the air.
  • the refrigerant flowing out of the outdoor heat exchanger 3 is sucked into the compressor 1 again through the flow path switching valve 2 and compressed. During the heating operation, the above cycle is repeated to heat the room.
  • FIG. 3 is a flowchart of control performed by the control device when the cooling operation is stopped in low outside air.
  • FIG. 4 is a diagram showing the operation of each device in the first control.
  • the compressor 1 When the air conditioner 100 is performing the cooling operation, as shown in FIGS. 1 and 4, the compressor 1 is operated, the flow path switching valve 2 is on the cooling side, and the first on-off valve 31 and the first on-off valve 31 and the second (2) The on-off valve 32 is fully opened, and the refrigerant circulates in the refrigerant circuit 100a in the cycle during the cooling operation.
  • the frequency of the compressor 1, the opening degree of the expansion valve 4, the outdoor fan 11 and the indoor fan 21 are controlled by the control device 50 according to the load and setting in the room.
  • step S1 When a command to stop the cooling operation is input during the cooling operation, the control shown in FIG. 3 is started, and the operation stop process is first performed (step S1). Specifically, the operation of the indoor fan 21 and the operation of the outdoor fan 11 are stopped.
  • the timing at which the control of FIG. 3 starts is not limited to the time when a command is input via the remote controller. For example, when the end time of the cooling operation is determined by the timer function or the like, the control of FIG. 3 is automatically started when the end time is reached.
  • step S1 the control device 50 determines whether or not the outside air temperature To detected by the first sensor 41 is equal to or lower than the room temperature Ti detected by the second sensor 42 (step S2). When the outside air temperature To is higher than the room temperature Ti, the control device 50 determines that the outside air temperature To is not below the room temperature Ti (step S2; NO), and immediately stops the compressor 1 (step S9). After the compressor 1 is stopped (step S9), the control of FIG. 3 ends.
  • step S2 when it is determined that the outside air temperature To is room temperature Ti or less (step S2; YES), the control device 50 performs the first control of steps S3 to S8. Specifically, the control device 50 first switches the flow path switching valve 2 to the heating side (step S3), fully closes the second on-off valve 32 (step S4), and stores the refrigerant in the indoor unit 20. To start.
  • FIG. 5 is an explanatory diagram showing the refrigerant flow of the refrigerant circuit when the first control storage process is being performed.
  • the amount of refrigerant in the outdoor heat exchanger 3 and the amount of refrigerant in the indoor heat exchanger 5 at the start of the storage process are schematically shown by diagonal lines.
  • the compressor 1 is operated when the storage process is being carried out.
  • the refrigerant discharged from the compressor 1 flows into the indoor heat exchanger 5 via the flow path switching valve 2, the connection pipe 8, and the first on-off valve 31, and is fully closed.
  • the second on-off valve 32 blocks the outflow from the indoor unit 20 and stores the heat mainly in the indoor heat exchanger 5.
  • the refrigerant in the outdoor heat exchanger 3 decreases.
  • the control device 50 When the storage process is started and the set time elapses, the control device 50 has the same temperature Tex of the outdoor heat exchanger 3 detected by the third sensor 43 as the outside air temperature To detected by the first sensor 41. Whether or not it is determined (step S5). Immediately after the storage process is started, the temperature Thex of the outdoor heat exchanger 3 is equal to or lower than the outside air temperature To. When the storage process is being carried out, the amount of refrigerant in the outdoor heat exchanger 3 is reduced by moving the refrigerant on the outdoor unit 10 side to the indoor unit 20 side by the cycle shown in FIG. Therefore, the heat transfer tube of the outdoor heat exchanger 3 is cooled by the outside air, and the temperature Thex of the outdoor heat exchanger 3 gradually decreases.
  • step S5 determines whether or not the storage process is completed.
  • step S5 when the temperature Thex of the outdoor heat exchanger 3 is not the outside air temperature To (step S5; NO), it is determined that the storage process has not been completed yet, and the control device 50 determines the predetermined time. When the elapse has passed, the determination in step S5 is performed again. The determination in step S5 is repeated until the temperature Thex of the outdoor heat exchanger 3 reaches the outside air temperature To. When the temperature Thex of the outdoor heat exchanger 3 reaches the outside air temperature To (step S5; YES), it is determined that the storage process is completed, and the control device 50 fully closes the first on-off valve 31, which is fully open. (Step S6), and the compressor 1 is stopped (step S7).
  • FIG. 6 is a refrigerant circuit diagram showing a state in which the refrigerant is sealed in the indoor unit after the storage process of FIG. 5 is completed.
  • the amount of refrigerant in the outdoor heat exchanger 3 and the amount of refrigerant in the indoor heat exchanger 5 at the start of the storage process are schematically shown by diagonal lines.
  • the outflow of the refrigerant stored on the indoor unit 20 side to the outdoor unit 10 side by the storage process is suppressed. , The refrigerant is trapped in the indoor unit 20.
  • the refrigerant is stored in the region between the first on-off valve 31 and the second on-off valve 32, including the indoor heat exchanger 5.
  • the above storage process is performed when the cooling operation is stopped, so that the indoor heat exchanger 5 is performing the cooling operation after the cooling operation is stopped. There will be more refrigerant than.
  • the control device 50 controls the inverter so that the compressor 1 is constrained and energized (step S8).
  • the restraint energization means energizing the motor windings without driving the compressor motor, and the compressor 1 can be preheated by the restraint energization.
  • a high frequency AC voltage of several kHz or more is output to the compressor motor.
  • the outdoor unit 10 including the compressor 1 is cooled by the outside air and becomes the same temperature as the outside air temperature.
  • the refrigerant is cooled while flowing in the outdoor unit 10 and flows into the indoor unit 20. Therefore, when the cooling operation is started, a particularly low temperature refrigerant flows into the indoor unit 20, so that the surface temperature of the heat transfer tube of the indoor heat exchanger 5 tends to be lower than the set temperature, and the antifreeze control functions to cause the compressor 1 to function. It may be stopped.
  • the temperature drop of the refrigerant is suppressed by performing the restraint energization of the compressor 1 as one step of the first control, and the cooling operation is constantly performed by the antifreeze control at the start of the cooling operation. Is prevented from being hindered.
  • the restraint energization of the compressor 1 it is possible to prevent the occurrence of the refrigerant stagnation phenomenon in which the refrigerant accumulates in the compressor 1 while the operation is stopped.
  • FIG. 7 is a flowchart of the second control performed by the control device at the start of the cooling operation in low outside air.
  • FIG. 8 is a diagram showing the operation of each device in the second control.
  • the compressor 1 When the air conditioner 100 is stopped in operation after the storage process is performed, the compressor 1 is stopped and the flow path switching valve 2 is set to the cooling side, as shown in FIGS. 6 and 8.
  • the first on-off valve 31 and the second on-off valve 32 are fully closed, and the refrigerant is sealed on the indoor unit 20 side.
  • the expansion valve 4 is closed and the outdoor fan 11 is stopped.
  • step S11 the control device 50 performs an operation start process (step S11), fully opens the first on-off valve 31 that is fully closed (step S12), and fully opens the closed expansion valve 4. (Step S13).
  • step S11 the compressor 1 is activated and the indoor fan 21 starts operation.
  • the timing at which the second control starts is not limited to the time when the command is input via the remote controller. For example, when the start time of the refrigerant operation is determined by the timer function or the like, the second control is automatically disclosed when the start time is reached.
  • FIG. 9 is an explanatory diagram showing the refrigerant flow of the refrigerant circuit when the release process of the second control is being performed.
  • the flow path switching valve 2 is on the cooling side.
  • the refrigerant stored in the indoor heat exchanger 5 flows into the outdoor unit 10 through the first on-off valve 31 and the connecting pipe 8 which are fully opened by the operation of the compressor 1.
  • the refrigerant released from the indoor unit 20 and flowing into the outdoor unit 10 passes through the flow path switching valve 2 and is sucked into the compressor 1, compressed and flows into the outdoor heat exchanger 3.
  • the refrigerant flowing into the outdoor heat exchanger 3 tries to flow into the indoor unit 20 side through the expansion valve 4 which is fully opened and through the connection pipe 7, but the second on-off valve 32 which is fully closed. This prevents the movement to the indoor heat exchanger 5. Therefore, at the start of the cooling operation, it is possible to prevent the low-temperature refrigerant existing in the outdoor heat exchanger 3 while the operation is stopped from directly flowing into the indoor heat exchanger 5.
  • the outdoor fan 11 is stopped while the compressor 1 is operated, and the expansion valve 4 is fully opened, so that the outdoor unit of the second on-off valve 32 including the connection pipe 7 is operated.
  • the refrigerant discharged from the compressor 1 can easily move to the refrigerant pipe on the 10 side. Therefore, when the release process is being performed, the temperature of the refrigerant existing in the refrigerant pipe on the outdoor unit 10 side of the second on-off valve 32 rises.
  • the control device 50 determines whether or not the temperature Tex of the outdoor heat exchanger 3 detected by the third sensor 43 is equal to or higher than the outside air temperature To detected by the first sensor 41. Is determined (step S14). When the temperature Thex of the outdoor heat exchanger 3 is less than the outside air temperature To (step S14; NO), the control device 50 re-determines step S14 when a predetermined time has elapsed. The determination in step S14 is repeated until the temperature Thex of the outdoor heat exchanger 3 becomes equal to or higher than the outside air temperature To.
  • step S14 when the temperature Thex of the outdoor heat exchanger 3 becomes equal to or higher than the outside air temperature To (YES in step S14; YES), the control device 50 ends the release process and starts the normal cooling operation. Specifically, the control device 50 starts the operation of the stopped outdoor fan 11 (step S15), and fully opens the second on-off valve 32 that is fully closed (step S16). After step S16, the control of FIG. 7 ends.
  • the refrigerant blocked by the second on-off valve 32 in the release process flows into the indoor heat exchanger 5 when the second on-off valve 32 is fully opened.
  • the indoor heat exchanger 5 since the temperature of the refrigerant flowing into the indoor heat exchanger 5 rises during the release process, the indoor heat exchanger 5 is extremely cooled at the start of the cooling operation after the release process is completed. Can be avoided. Therefore, even in a low outside air environment, it is possible to prevent the antifreezing control from functioning at the start of the cooling operation, and it is possible to perform a steady cooling operation.
  • a cooling operation is performed in which the refrigerant circulates in the refrigerant circuit 100a in the cycle shown in FIG. 1, and the frequency of the compressor 1, the opening degree of the expansion valve 4, and the rotation speed of the outdoor fan 11 are performed according to the load in the room. Is controlled.
  • the air conditioner 100 includes a refrigerant circuit 100a, a first on-off valve 31, and a second on-off valve 32.
  • the first on-off valve 31 is provided between one of the inlet and outlet of the indoor heat exchanger 5 and the flow path switching valve 2 in the refrigerant circuit 100a, and is arranged in the indoor unit 20.
  • the second on-off valve 32 is provided between the other of the inlet and outlet of the indoor heat exchanger 5 and the expansion valve 4 in the refrigerant circuit 100a, and is arranged in the indoor unit 20.
  • the first on-off valve 31 and the second on-off valve 32 can store the refrigerant in the refrigerant circuit 100a on the indoor unit 20 side including the indoor heat exchanger 5. Therefore, even in a low outside air environment, it is possible to suppress a decrease in the refrigerant temperature due to the outside air temperature when the operation is stopped, and it is possible to prevent the antifreezing control suppression from functioning when the cooling operation is restarted, so that the cooling operation can be continuously performed.
  • the air conditioner 100 includes a first sensor 41 that detects the outside air temperature To, a second sensor 42 that detects the room temperature of the air-conditioned space, and a control device 50.
  • the control device 50 switches the flow path switching valve 2 when the outside air temperature To detected by the first sensor 41 is equal to or lower than the room temperature Ti detected by the second sensor 42.
  • Control is performed so that the on-off valve 32 is fully closed. With such control, it is possible to easily realize that the refrigerant is moved to the indoor unit 20 side and stored when the cooling operation is stopped in a low outside air environment.
  • the air conditioner 100 further includes a third sensor 43 that detects the temperature Tex of the outdoor heat exchanger 3, and the control device 50 further starts the storage process, and then the temperature Tex of the outdoor heat exchanger 3 changes to the outside air temperature.
  • the first on-off valve 31 is controlled to be fully closed. As a result, it is possible to prevent the outflow of the stored refrigerant that has moved to the indoor unit 20 side by the storage process and to keep the refrigerant sealed in the indoor unit 20 while the operation is stopped.
  • control device 50 stops the compressor 1 after completing the storage process by fully closing the first on-off valve 31, and controls the compressor 1 so as to be restrained and energized.
  • the compressor 1 can be preheated, and the temperature drop of the refrigerant existing on the outdoor unit 10 side due to the outside air can be delayed. Therefore, the temperature drop of the refrigerant flowing into the indoor unit 20 when the cooling operation is restarted can be minimized while the operation is stopped, and the effect that the steady cooling operation can be performed can be further enhanced. Further, by restraining energization, it is possible to suppress the occurrence of the refrigerant sneaking phenomenon during the operation stop.
  • control device 50 starts the compressor 1 and fully opens the first on-off valve 31 to fully open the expansion valve when the cooling operation is restarted after the cooling operation is stopped when the outside air temperature To is room temperature Ti or less. Control is performed so that 4 is fully opened.
  • the first on-off valve 31 and the second on-off valve 32 arranged in the indoor unit 20 operate in this way by the control device 50, so that the refrigerant cooled by the outside air in the outdoor heat exchanger 3 when the operation is stopped is released. It is possible to prevent the indoor unit 20 from flowing into the indoor unit 20 at the same temperature. Further, since the temperature of the refrigerant flowing into the indoor unit 20 can be raised when the cooling operation is restarted, it is possible to prevent the evaporation temperature from decreasing in the cycle during the cooling operation.
  • the control device 50 restarts the cooling operation after the storage process is performed and the operation of the air conditioner 100 is stopped, the temperature Thex of the outdoor heat exchanger 3 is equal to or higher than the outside air temperature To after the release process is started.
  • the second on-off valve 32 is controlled to be fully opened.
  • control device 50 that controls the compressor 1 also has a function of controlling the first on-off valve 31 and the second on-off valve 32, but controls that control the first on-off valve 31 and the second on-off valve 32.
  • the substrate may be provided separately from the control device 50. In this case, the control board and the control device 50 are electrically connected.
  • the first control includes the step of restraint energization for the compressor 1, but the restraint energization can be omitted.
  • the air conditioner 100 may be configured to perform restraint energization at a predetermined timing while the operation is stopped.
  • 1 Compressor 2 Flow path switching valve, 3 Outdoor heat exchanger, 4 Expansion valve, 5 Indoor heat exchanger, 7, 8 Connection piping, 10 Outdoor unit, 11 Outdoor fan, 20 Indoor unit, 21 Indoor fan, 27, 28 Indoor piping, 31 1st on-off valve, 32 2nd on-off valve, 41 1st sensor, 42 2nd sensor, 43 3rd sensor, 44 4th sensor, 50 control device, 51 input unit, 52 main control unit, 53 Storage unit, 100 air conditioner, 100a refrigerant circuit, The temperature of the outdoor heat exchanger, Ti room temperature, To outside temperature.

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Abstract

This air conditioner, in which an indoor unit installed in a space to be air-conditioned and an outdoor unit are connected, comprises: a refrigerant circuit that is configured by a compressor, a flow path switching valve, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger being connected by refrigerant piping; a first open/close valve that is provided between either the inlet port or the outlet port of the indoor heat exchanger and the flow path switching valve in the refrigerant circuit, and disposed in the indoor unit; and a second open/close valve that is provided between the other port of the indoor heat exchanger and the expansion valve in the refrigerant circuit, and disposed in the indoor unit.

Description

空気調和機Air conditioner
　本開示は、空気調和機に関し、特に、低外気温における冷房運転に関する。 This disclosure relates to an air conditioner, particularly to a cooling operation at a low outside air temperature.
　一般に空気調和機は、圧縮機と、凝縮器と、膨張弁と、蒸発器とが冷媒配管により接続された冷媒回路を有している。空気調和機は、例えば、電算機又は電話交換機のような発熱する機器が設置された機械室に設置され、冷房運転を行うことで、機器の発熱による機械室の室温の上昇を抑制する。機械室等に設置された空気調和機は、季節を問わず冷房運転を行う必要がある。しかしながら、外気温が氷点下となる低外気環境下では、空気調和機の運転停止中において室外機に存在する冷媒は外気により冷却され、室外機に搭載された圧縮機及び凝縮器等の機器に溜まり込む。従来の空気調和機において、運転停止中における圧縮機への冷媒の溜まり込みすなわち冷媒寝込みを防止する構成を備えたものがある（例えば、特許文献１参照）。特許文献１には、凝縮器と蒸発器とを接続する冷媒配管のうち室外機側にある冷媒配管と並列に冷媒ボンベを含む並列回路を設け、並列回路において冷媒ボンベの前後に２つの電磁弁を設けることが開示されている。 Generally, an air conditioner has a refrigerant circuit in which a compressor, a condenser, an expansion valve, and an evaporator are connected by a refrigerant pipe. The air conditioner is installed in a machine room in which a heat-generating device such as a computer or a telephone exchange is installed, and performs a cooling operation to suppress an increase in the room temperature of the machine room due to the heat generated by the device. Air conditioners installed in machine rooms, etc. need to be cooled regardless of the season. However, in a low outside air environment where the outside air temperature is below freezing, the refrigerant existing in the outdoor unit is cooled by the outside air while the operation of the air conditioner is stopped, and accumulates in equipment such as the compressor and condenser mounted on the outdoor unit. Include. Some conventional air conditioners have a configuration that prevents the refrigerant from accumulating in the compressor, that is, the refrigerant from falling asleep when the operation is stopped (see, for example, Patent Document 1). In Patent Document 1, a parallel circuit including a refrigerant cylinder is provided in parallel with the refrigerant pipe on the outdoor unit side of the refrigerant pipes connecting the condenser and the evaporator, and two solenoid valves are provided before and after the refrigerant cylinder in the parallel circuit. Is disclosed to be provided.
　ところで、一般に空気調和機は、冷房運転に室内機の蒸発器に発生した結露水の凍結を防ぐために、蒸発器の温度が設定温度以下になると圧縮機を停止させる凍結防止制御を行うように構成されている。 By the way, in general, an air conditioner is configured to perform antifreezing control to stop the compressor when the temperature of the evaporator becomes lower than the set temperature in order to prevent the condensed water generated in the evaporator of the indoor unit from freezing during the cooling operation. Has been done.
特開２０１５－１９０７１２号公報Japanese Unexamined Patent Publication No. 2015-190712
　特許文献１の空気調和機において、低外気温環境下で冷媒ボンベへ冷媒が回収されるので、圧縮機における冷媒の溜まり込みが抑制され、冷房運転を開始することはできる。しかし、特許文献１の空気調和機において、冷媒ボンベは室外機に配置されているので、低外気環境下において運転停止中に冷媒ボンベ中の冷媒が外気により冷却され、冷房運転の開始時に定常な運転が行えない。つまり、低外気環境下で空気調和機の冷房運転を開始する際、外気により冷却された低温の液冷媒が室内機の蒸発器に流入することにより凍結防止制御が機能し、圧縮機が停止されるので、定常な冷房運転を行うことができない。 In the air conditioner of Patent Document 1, since the refrigerant is recovered in the refrigerant cylinder in a low outside air temperature environment, the accumulation of the refrigerant in the compressor is suppressed, and the cooling operation can be started. However, in the air conditioner of Patent Document 1, since the refrigerant cylinder is arranged in the outdoor unit, the refrigerant in the refrigerant cylinder is cooled by the outside air while the operation is stopped in a low outside air environment, and is steady at the start of the cooling operation. I can't drive. That is, when the cooling operation of the air conditioner is started in a low outside air environment, the low temperature liquid refrigerant cooled by the outside air flows into the evaporator of the indoor unit, so that the antifreeze control functions and the compressor is stopped. Therefore, it is not possible to perform a steady cooling operation.
　本開示は、上記のような課題を解決するためになされたもので、低外気環境下における冷房運転において、定常な冷房運転を行うことができる空気調和機を提供することを目的とする。 The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide an air conditioner capable of performing a steady cooling operation in a cooling operation in a low outside air environment.
　本開示に係る空気調和機は、空調対象空間に設置される室内機と、室外機とが接続された空気調和機において、圧縮機と、流路切替弁と、室外熱交換器と、膨張弁と、室内熱交換器と、が冷媒配管により接続された冷媒回路と、前記冷媒回路において前記室内熱交換器の出入口の一方と前記流路切替弁との間に設けられ、前記室内機に配置された第一開閉弁と、前記冷媒回路において前記室内熱交換器の前記出入口の他方と前記膨張弁との間に設けられ、前記室内機に配置された第二開閉弁と、を備えるものである。 The air conditioner according to the present disclosure is an air conditioner in which an indoor unit installed in an air-conditioned space and an outdoor unit are connected, and is a compressor, a flow path switching valve, an outdoor heat exchanger, and an expansion valve. And the indoor heat exchanger are provided in the refrigerant circuit connected by the refrigerant pipe, and in the refrigerant circuit between one of the inlet / outlet of the indoor heat exchanger and the flow path switching valve, and arranged in the indoor unit. It is provided with a first on-off valve provided, and a second on-off valve provided between the other of the inlet and outlet of the indoor heat exchanger and the expansion valve in the refrigerant circuit and arranged in the indoor unit. be.
　本開示によれば、室内機に第一開閉弁及び第二開閉弁が配置されているので、これらの開閉弁を利用して室内機に冷媒を貯留することができ、低外気環境下でも運転停止中における外気温による冷媒温度の低下を抑制し、冷房運転の再開時に定常な運転ができる。 According to the present disclosure, since the first on-off valve and the second on-off valve are arranged in the indoor unit, the refrigerant can be stored in the indoor unit by using these on-off valves, and the operation can be performed even in a low outside air environment. It suppresses the decrease in the refrigerant temperature due to the outside air temperature during stoppage, and enables steady operation when the cooling operation is restarted.
実施の形態１に係る空気調和機の冷媒回路の一例を示す概略図である。It is the schematic which shows an example of the refrigerant circuit of the air conditioner which concerns on Embodiment 1. FIG. 図１に記載された制御装置の機能を示す機能ブロック図である。It is a functional block diagram which shows the function of the control device described in FIG. 低外気において冷房運転の停止時に制御装置が行う制御のフローチャートである。It is a flowchart of the control performed by the control device when the cooling operation is stopped in low outside air. 第一制御における各機器の動作を示す図である。It is a figure which shows the operation of each device in the 1st control. 第一制御の貯留処理が行われているときの冷媒回路の冷媒流れを示す説明図である。It is explanatory drawing which shows the refrigerant flow of the refrigerant circuit at the time of performing the storage process of the 1st control. 図５の貯留処理の完了後に室内機に冷媒が封止された状態を示す冷媒回路図である。It is a refrigerant circuit diagram which shows the state which the refrigerant is sealed in the indoor unit after the completion of the storage process of FIG. 低外気において冷房運転の開始時に制御装置が行う第二制御のフローチャートである。It is a flowchart of the second control performed by a control device at the start of a cooling operation in low outside air. 第二制御における各機器の動作を示す図である。It is a figure which shows the operation of each device in the 2nd control. 第二制御の解放処理が行われているときの冷媒回路の冷媒流れを示す説明図である。It is explanatory drawing which shows the refrigerant flow of the refrigerant circuit when the release process of the 2nd control is performed.
実施の形態１．
　図１は、実施の形態１に係る空気調和機の冷媒回路の一例を示す概略図である。空気調和機１００は、空調対象空間である部屋（室内）に設置される室内機２０、及び、室内機２０と接続され、例えば屋外（室外）に設置される室外機１０を備える。また空気調和機１００は、室外機１０及び室内機２０を構成する各機器を制御することにより空気調和機１００の運転を制御する制御装置５０を備えている。 Embodiment 1.
FIG. 1 is a schematic view showing an example of a refrigerant circuit of the air conditioner according to the first embodiment. The air conditioner 100 includes an indoor unit 20 installed in a room (indoor) which is an air-conditioned space, and an outdoor unit 10 connected to the indoor unit 20 and installed outdoors (outdoors), for example. Further, the air conditioner 100 includes a control device 50 that controls the operation of the air conditioner 100 by controlling each device constituting the outdoor unit 10 and the indoor unit 20.
　室内機２０は、室内熱交換器５を備えている。室外機１０は、圧縮機１と、流路切替弁２と、室外熱交換器３と、膨張弁４等とを備えている。これらの圧縮機１、流路切替弁２、室外熱交換器３、膨張弁４及び室内熱交換器５が冷媒配管を介して環状に接続されて冷媒回路１００ａを構成している。冷媒回路１００ａには、冷媒が充填されている。冷媒の種類は特に限定されない。 The indoor unit 20 includes an indoor heat exchanger 5. The outdoor unit 10 includes a compressor 1, a flow path switching valve 2, an outdoor heat exchanger 3, an expansion valve 4, and the like. These compressor 1, flow path switching valve 2, outdoor heat exchanger 3, expansion valve 4, and indoor heat exchanger 5 are connected in an annular shape via a refrigerant pipe to form a refrigerant circuit 100a. The refrigerant circuit 100a is filled with a refrigerant. The type of refrigerant is not particularly limited.
　室外機１０と室内機２０とは、２つの接続配管７、８により接続されている。接続配管７は、膨張弁４と室内熱交換器５との間において室外機１０と室内機２０とを接続し、接続配管７にはガス冷媒が流通する。接続配管８は、室内熱交換器５と流路切替弁２との間において室外機１０と室内機２０とを接続し、接続配管８には液冷媒が流通する。室内機２０は、室内熱交換器５における冷媒出入口の一方と接続配管８とを接続する室内配管２８、及び、室内熱交換器５における冷媒出入口の他方と接続配管７とを接続する室内配管２７を有する。 The outdoor unit 10 and the indoor unit 20 are connected by two connecting pipes 7 and 8. The connection pipe 7 connects the outdoor unit 10 and the indoor unit 20 between the expansion valve 4 and the indoor heat exchanger 5, and a gas refrigerant flows through the connection pipe 7. The connection pipe 8 connects the outdoor unit 10 and the indoor unit 20 between the indoor heat exchanger 5 and the flow path switching valve 2, and a liquid refrigerant flows through the connection pipe 8. The indoor unit 20 includes an indoor pipe 28 that connects one of the refrigerant inlets and outlets of the indoor heat exchanger 5 and the connection pipe 8, and an indoor pipe 27 that connects the other of the refrigerant inlets and outlets of the indoor heat exchanger 5 and the connection pipe 7. Has.
　圧縮機１は、冷媒を圧縮して吐き出し、循環させるものである。図示していないが、圧縮機１は、外郭であるシェルの内部に、冷媒を圧縮する圧縮機構と、圧縮機構を動作させる圧縮機モータとを有して構成される。圧縮機モータは、Ｕ相、Ｖ相及びＷ相の三相のモータ巻線を有する三相モータである。圧縮機モータには、図示していないインバータにより電圧が印加される。 The compressor 1 compresses the refrigerant, discharges it, and circulates it. Although not shown, the compressor 1 is configured to include a compression mechanism for compressing the refrigerant and a compressor motor for operating the compression mechanism inside a shell which is an outer shell. The compressor motor is a three-phase motor having three-phase motor windings of U-phase, V-phase and W-phase. A voltage is applied to the compressor motor by an inverter (not shown).
　流路切替弁２は、例えば四方弁で構成され、空気調和機１００の冷房運転と暖房運転とにおいて冷媒回路１００ａの流路を切り替え、冷媒の流通方向を切り替えるものである。冷房運転では、圧縮機１の吐出側が室外熱交換器３に接続され、暖房運転では、圧縮機１の吸入側が室外熱交換器３に接続される。図１には、空気調和機１００が冷房運転をしているとき流路切替弁２の接続状態が図示されている。なお、流路切替弁２は、三方切替弁又は二方切替弁等を組み合わせた構成でもよい。 The flow path switching valve 2 is composed of, for example, a four-way valve, and switches the flow path of the refrigerant circuit 100a between the cooling operation and the heating operation of the air conditioner 100 to switch the flow direction of the refrigerant. In the cooling operation, the discharge side of the compressor 1 is connected to the outdoor heat exchanger 3, and in the heating operation, the suction side of the compressor 1 is connected to the outdoor heat exchanger 3. FIG. 1 shows a connection state of the flow path switching valve 2 when the air conditioner 100 is in the cooling operation. The flow path switching valve 2 may have a configuration in which a three-way switching valve, a two-way switching valve, or the like is combined.
　室外熱交換器３は、冷媒と外気との間で熱交換を行うものであり、例えば複数のフィンと複数の伝熱管とを有するフィンアンドチューブ型熱交換器で構成される。空気調和機１００が冷房運転をしているとき、室外熱交換器３は凝縮器として作用し、空気調和機１００が暖房運転をしているとき、室外熱交換器３は蒸発器として作用する。膨張弁４は、冷媒を減圧して膨張させるものである。 The outdoor heat exchanger 3 exchanges heat between the refrigerant and the outside air, and is composed of, for example, a fin-and-tube heat exchanger having a plurality of fins and a plurality of heat transfer tubes. When the air conditioner 100 is in the cooling operation, the outdoor heat exchanger 3 acts as a condenser, and when the air conditioner 100 is in the heating operation, the outdoor heat exchanger 3 acts as an evaporator. The expansion valve 4 decompresses and expands the refrigerant.
　室内熱交換器５は、冷媒と室内空気との間で熱交換を行うものであり、例えば複数のフィンと複数の伝熱管とを有するフィンアンドチューブ型熱交換器で構成される。空気調和機１００が冷房運転をしているとき、室内熱交換器５は蒸発器として作用し、空気調和機１００が暖房運転をしているとき、室内熱交換器５は凝縮器として作用する。 The indoor heat exchanger 5 exchanges heat between the refrigerant and the indoor air, and is composed of, for example, a fin-and-tube heat exchanger having a plurality of fins and a plurality of heat transfer tubes. When the air conditioner 100 is in the cooling operation, the indoor heat exchanger 5 acts as an evaporator, and when the air conditioner 100 is in the heating operation, the indoor heat exchanger 5 acts as a condenser.
　また室内機２０は、室内熱交換器５に送風する室内ファン２１を更に備えている。また室外機１０は、室外熱交換器３に送風する室外ファン１１を更に備えている。 Further, the indoor unit 20 further includes an indoor fan 21 that blows air to the indoor heat exchanger 5. Further, the outdoor unit 10 further includes an outdoor fan 11 that blows air to the outdoor heat exchanger 3.
　また室内機２０は、室内機２０に冷媒を貯留可能とする２つの開閉弁（第一開閉弁３１及び第二開閉弁３２）を有している。第一開閉弁３１及び第二開閉弁３２はそれぞれ、例えば電磁開閉弁で構成される。ガス冷媒が流通する室内配管２８に第一開閉弁３１が設けられ、液冷媒が流通する室内配管２７に第二開閉弁３２が設けられている。 Further, the indoor unit 20 has two on-off valves (first on-off valve 31 and second on-off valve 32) capable of storing the refrigerant in the indoor unit 20. The first on-off valve 31 and the second on-off valve 32 are each composed of, for example, an electromagnetic on-off valve. The first on-off valve 31 is provided in the indoor pipe 28 through which the gas refrigerant flows, and the second on-off valve 32 is provided in the indoor pipe 27 in which the liquid refrigerant flows.
　また空気調和機１００は、複数のセンサを備えている。具体的には、空調対象空間である部屋の室温を検出する第二センサ４２、及び室内熱交換器５の温度を検出する第四センサ４４が設けられている。第二センサ４２は、例えば温度センサで構成され、室内機２０の筐体（不図示）に設けられた吸込口の近傍に配置されている。第四センサ４４は、例えば温度センサで構成され、室内熱交換器５の伝熱管に配置されて伝熱管の表面温度を検出する。第四センサ４４は、特に、室内熱交換器５における冷媒出入口をつなぐ伝熱管の中間の位置に設置されているとよい。 Further, the air conditioner 100 is provided with a plurality of sensors. Specifically, a second sensor 42 for detecting the room temperature of the room which is the space to be air-conditioned and a fourth sensor 44 for detecting the temperature of the indoor heat exchanger 5 are provided. The second sensor 42 is composed of, for example, a temperature sensor, and is arranged in the vicinity of a suction port provided in a housing (not shown) of the indoor unit 20. The fourth sensor 44 is composed of, for example, a temperature sensor, and is arranged in the heat transfer tube of the indoor heat exchanger 5 to detect the surface temperature of the heat transfer tube. In particular, the fourth sensor 44 may be installed at a position in the middle of the heat transfer tube connecting the refrigerant inlet / outlet in the indoor heat exchanger 5.
　室外機１０には、外気温を検出する第一センサ４１、及び室外熱交換器３の温度を検出する第三センサ４３が設けられている。第一センサ４１は例えば温度センサで構成される。第三センサ４３は、例えば温度センサで構成され、室外熱交換器３の伝熱管に配置されて伝熱管の表面温度を検出する。第三センサ４３は、特に、室外熱交換器３における２つの出入口をつなぐ伝熱管の中間の位置に設置されているとよい。なお、第三センサ４３は、圧力センサと制御装置５０とにより構成され、室外熱交換器３の伝熱管内の冷媒圧力を圧力センサにより検出し、検出された冷媒圧力から室外熱交換器３の温度を制御装置５０が演算してもよい。あるいは、運転時に凝縮温度を用いて圧縮機１等の制御がされる場合には、凝縮温度を検出するセンサを第三センサ４３として用いることができる。 The outdoor unit 10 is provided with a first sensor 41 for detecting the outside air temperature and a third sensor 43 for detecting the temperature of the outdoor heat exchanger 3. The first sensor 41 is composed of, for example, a temperature sensor. The third sensor 43 is composed of, for example, a temperature sensor, and is arranged in the heat transfer tube of the outdoor heat exchanger 3 to detect the surface temperature of the heat transfer tube. In particular, the third sensor 43 may be installed at a position intermediate between the heat transfer tubes connecting the two entrances and exits of the outdoor heat exchanger 3. The third sensor 43 is composed of a pressure sensor and a control device 50. The pressure sensor detects the refrigerant pressure in the heat transfer tube of the outdoor heat exchanger 3, and the detected refrigerant pressure of the outdoor heat exchanger 3 is used. The control device 50 may calculate the temperature. Alternatively, when the compressor 1 or the like is controlled by using the condensation temperature during operation, a sensor that detects the condensation temperature can be used as the third sensor 43.
　制御装置５０は、専用のハードウェア、又はメモリに格納されるプログラムを実行するＣＰＵ（Ｃｅｎｔｒａｌ　Ｐｒｏｃｅｓｓｉｎｇ　Ｕｎｉｔ）で構成されている。なお、ＣＰＵは、中央処理装置、処理装置、演算装置、マイクロプロセッサ、マイクロコンピュータ、又はプロセッサともいう。 The control device 50 is composed of dedicated hardware or a CPU (Central Processing Unit) that executes a program stored in a memory. The CPU is also referred to as a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, or a processor.
　制御装置５０が専用のハードウェアである場合、制御装置５０は、例えば、単一回路、複合回路、ＡＳＩＣ（Ａｐｐｌｉｃａｔｉｏｎ　Ｓｐｅｃｉｆｉｃ　Ｉｎｔｅｇｒａｔｅｄ　Ｃｉｒｃｕｉｔ）、ＦＰＧＡ（Ｆｉｅｌｄ－Ｐｒｏｇｒａｍｍａｂｌｅ　Ｇａｔｅ　Ａｒｒａｙ）、又はこれらを組み合わせたものが該当する。制御装置５０が実現する各機能部のそれぞれを、個別のハードウェアで実現してもよいし、各機能部を一つのハードウェアで実現してもよい。 When the control device 50 is dedicated hardware, the control device 50 may be, for example, a single circuit, a composite circuit, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof. Applicable. Each of the functional units realized by the control device 50 may be realized by individual hardware, or each functional unit may be realized by one hardware.
　制御装置５０がＣＰＵの場合、制御装置５０が実行する各機能は、ソフトウェア、ファームウェア、又はソフトウェアとファームウェアとの組み合わせにより実現される。ソフトウェア及びファームウェアはプログラムとして記述され、メモリに格納される。ＣＰＵは、メモリに格納されたプログラムを読み出して実行することにより、制御装置５０の各機能を実現する。ここで、メモリは、例えば、ＲＡＭ、ＲＯＭ、フラッシュメモリ、ＥＰＲＯＭ、又はＥＥＰＲＯＭ等の、不揮発性又は揮発性の半導体メモリである。 When the control device 50 is a CPU, each function executed by the control device 50 is 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 each function of the control device 50 by reading and executing the program stored in the memory. Here, the memory is a non-volatile or volatile semiconductor memory such as RAM, ROM, flash memory, EPROM, or EEPROM.
　制御装置５０の機能の一部を専用のハードウェアで実現し、一部をソフトウェア又はファームウェアで実現するようにしてもよい。 A part of the function of the control device 50 may be realized by dedicated hardware, and a part may be realized by software or firmware.
　制御装置５０は、第一センサ４１、第二センサ４２、第三センサ４３及び第四センサ４４を含む複数のセンサそれぞれと電気的に接続されており、制御装置５０には、複数のセンサの検出情報が入力される。また制御装置５０には、不図示のリモートコントローラから、冷房運転の開始及び停止、暖房運転の開始及び停止、冷房運転時の設定温度、並びに暖房運転時の設定温度等が入力される。制御装置５０は、入力された情報に基づいて室外機１０及び室内機２０を構成する各機器の動作を制御する。 The control device 50 is electrically connected to each of a plurality of sensors including the first sensor 41, the second sensor 42, the third sensor 43, and the fourth sensor 44, and the control device 50 detects the plurality of sensors. Information is entered. Further, from a remote controller (not shown), the start and stop of the cooling operation, the start and stop of the heating operation, the set temperature during the cooling operation, the set temperature during the heating operation, and the like are input to the control device 50. The control device 50 controls the operation of each device constituting the outdoor unit 10 and the indoor unit 20 based on the input information.
　図２は、図１に記載された制御装置の機能を示す機能ブロック図である。制御装置５０は、機能部として、入力部５１と、主制御部５２と、記憶部５３を備えている。入力部５１には、複数のセンサの検出情報及びリモートコントローラを介した情報等が入力される。記憶部５３には、入力部５１に入力された情報及び主制御部５２が各機器の制御に用いる設定値及び制御目標値等が記憶されている。主制御部５２は、入力部５１に入力された情報に基づいて、圧縮機１の周波数、流路切替弁２の切り替え、膨張弁４の開度、室外ファン１１の回転数、及び室内ファン２１の回転数等を制御する。また主制御部５２は、入力部５１に入力された情報に基づいて、第一開閉弁３１及び第二開閉弁３２の動作を制御する。具体的には、冷房運転が行われている間、及び暖房運転が行われている間、主制御部５２は、第一開閉弁３１及び第二開閉弁３２を全開とする。 FIG. 2 is a functional block diagram showing the functions of the control device shown in FIG. The control device 50 includes an input unit 51, a main control unit 52, and a storage unit 53 as functional units. The detection information of a plurality of sensors, the information via the remote controller, and the like are input to the input unit 51. The storage unit 53 stores the information input to the input unit 51, the set value used by the main control unit 52 to control each device, the control target value, and the like. Based on the information input to the input unit 51, the main control unit 52 switches the frequency of the compressor 1, the flow path switching valve 2, the opening degree of the expansion valve 4, the rotation speed of the outdoor fan 11, and the indoor fan 21. Controls the number of rotations, etc. Further, the main control unit 52 controls the operations of the first on-off valve 31 and the second on-off valve 32 based on the information input to the input unit 51. Specifically, the main control unit 52 fully opens the first on-off valve 31 and the second on-off valve 32 during the cooling operation and the heating operation.
　空気調和機１００は、冷房運転時において室内熱交換器５の温度が設定温度以下である場合に、室内熱交換器５の伝熱管の表面に発生した結露水が凍結することを防止する凍結防止機能を備えている。具体的には、主制御部５２は、空気調和機１００の冷房運転時に、第四センサ４４により検出された室内熱交換器５の温度が例えば３℃以下となった場合に、圧縮機１の運転を停止させる制御を行う。このような凍結防止制御により、室内熱交換器５の凍結を防ぎ、凍結による機器の破損を防止することができる。 The air conditioner 100 prevents the dew condensation water generated on the surface of the heat transfer tube of the indoor heat exchanger 5 from freezing when the temperature of the indoor heat exchanger 5 is equal to or lower than the set temperature during the cooling operation. It has a function. Specifically, the main control unit 52 sets the compressor 1 when the temperature of the indoor heat exchanger 5 detected by the fourth sensor 44 becomes, for example, 3 ° C. or lower during the cooling operation of the air conditioner 100. Controls to stop the operation. With such anti-freezing control, it is possible to prevent the indoor heat exchanger 5 from freezing and prevent damage to the equipment due to freezing.
　また主制御部５２は、空気調和機１００の冷房運転が停止される際に、第一センサ４１、第二センサ４２、及び第三センサ４３の検出情報に応じて、冷媒の貯留処理及び圧縮機１の予備加熱を含む第一制御を行う。具体的には、第一制御において、第一開閉弁３１、第二開閉弁３２、流路切替弁２及び圧縮機１が、予め決められた動作を行うように制御される。第一制御については、後述する。 Further, when the cooling operation of the air conditioner 100 is stopped, the main control unit 52 performs a refrigerant storage process and a compressor according to the detection information of the first sensor 41, the second sensor 42, and the third sensor 43. The first control including the preheating of 1 is performed. Specifically, in the first control, the first on-off valve 31, the second on-off valve 32, the flow path switching valve 2, and the compressor 1 are controlled to perform predetermined operations. The first control will be described later.
　また主制御部５２は、第一制御を実施して冷房運転が停止した後に冷房運転が再開される際に、第一センサ４１、第二センサ４２、及び第三センサ４３の検出情報に応じて、冷媒の解放処理を含む第二制御を行う。具体的には、第二制御において、第一開閉弁３１、第二開閉弁３２、膨張弁４、圧縮機１及び室外ファン１１が、予め決められた動作を行うように制御される。第二制御については、後述する。 Further, when the cooling operation is restarted after the first control is executed and the cooling operation is stopped, the main control unit 52 responds to the detection information of the first sensor 41, the second sensor 42, and the third sensor 43. , Performs a second control including the release process of the refrigerant. Specifically, in the second control, the first on-off valve 31, the second on-off valve 32, the expansion valve 4, the compressor 1, and the outdoor fan 11 are controlled to perform predetermined operations. The second control will be described later.
　まず、図１の空気調和機１００の冷房運転時及び暖房運転時の動作について説明する。冷房運転時、流路切替弁２は、図１の実線で示された接続状態とされている。図１には冷房運転時における冷媒流れの方向が実線の矢印で示されている。冷房運転時、冷媒は圧縮機１により圧縮されて高温高圧となり、流路切替弁２を介して室外熱交換器３に流入する。室外熱交換器３に流入した冷媒は、室外熱交換器３において周囲の空気すなわち外気に放熱することにより凝縮し、液化する。このとき、室外ファン１１の駆動により、冷媒と外気との熱交換が促進される。室外熱交換器３から流出した冷媒は、膨張弁４で減圧され膨張し、接続配管７を通って室内機２０に入る。室内機２０に入った冷媒は、全開とされている第二開閉弁３２を通って室内熱交換器５に流入する。室内熱交換器５に流入した冷媒は、室内熱交換器５において周囲の空気すなわち室内空気から吸熱することにより蒸発し、ガス化する。このとき、室内ファン２１の駆動により、冷媒と室内空気との熱交換が促進される。室内熱交換器５から流出した冷媒は、全開とされている第一開閉弁３１を通って室内機２０から流出し、接続配管８を介して室外機１０へ流入する。室外機１０に流入した冷媒は、流路切替弁２を介して再び圧縮機１に吸入され、圧縮される。冷房運転中、上記のサイクルが繰り返され、室内の冷房が行われる。 First, the operations of the air conditioner 100 of FIG. 1 during the cooling operation and the heating operation will be described. During the cooling operation, the flow path switching valve 2 is in the connected state shown by the solid line in FIG. In FIG. 1, the direction of the refrigerant flow during the cooling operation is indicated by a solid arrow. During the cooling operation, the refrigerant is compressed by the compressor 1 to a high temperature and high pressure, and flows into the outdoor heat exchanger 3 via the flow path switching valve 2. The refrigerant that has flowed into the outdoor heat exchanger 3 is condensed and liquefied by dissipating heat from the surrounding air, that is, the outside air in the outdoor heat exchanger 3. At this time, the drive of the outdoor fan 11 promotes heat exchange between the refrigerant and the outside air. The refrigerant flowing out of the outdoor heat exchanger 3 is decompressed by the expansion valve 4 to expand, and enters the indoor unit 20 through the connecting pipe 7. The refrigerant that has entered the indoor unit 20 flows into the indoor heat exchanger 5 through the second on-off valve 32 that is fully opened. The refrigerant flowing into the indoor heat exchanger 5 evaporates and gasifies by absorbing heat from the surrounding air, that is, the indoor air in the indoor heat exchanger 5. At this time, the drive of the indoor fan 21 promotes heat exchange between the refrigerant and the indoor air. The refrigerant flowing out of the indoor heat exchanger 5 flows out from the indoor unit 20 through the first on-off valve 31 which is fully opened, and flows into the outdoor unit 10 through the connection pipe 8. The refrigerant that has flowed into the outdoor unit 10 is sucked into the compressor 1 again via the flow path switching valve 2 and compressed. During the cooling operation, the above cycle is repeated to cool the room.
　暖房運転時、流路切替弁２は、図１の破線で示された接続状態とされている。暖房運転時、冷媒は圧縮機１により圧縮されて高温高圧となり、流路切替弁２を介して室外機１０から流出する。室外機１０から流出した冷媒は、接続配管８を介して室内機２０に流入し、全開とされている第一開閉弁３１を通って室内熱交換器５に流入する。室内熱交換器５に流入した冷媒は、室内熱交換器５において周囲の空気すなわち室内空気に放熱することにより凝縮し、液化する。このとき、室内ファン２１の駆動により、冷媒と空気との熱交換が促進される。室内熱交換器５から流出した冷媒は、全開とされている第二開閉弁３２を通って室内機２０から流出する。室内機２０から流出した冷媒は、接続配管７を通って室外機１０に流入し、膨張弁４で減圧され膨張し、室外熱交換器３に流入する。室外熱交換器３に流入した冷媒は、室外熱交換器３において周囲の空気すなわち外気から吸熱することにより蒸発し、ガス化する。このとき、室外ファン１１の駆動により、冷媒と空気との熱交換が促進される。室外熱交換器３から流出した冷媒は、流路切替弁２を介して再び圧縮機１に吸入され、圧縮される。暖房運転中、上記のサイクルが繰り返され、室内の暖房が行われる。 During the heating operation, the flow path switching valve 2 is in the connected state shown by the broken line in FIG. During the heating operation, the refrigerant is compressed by the compressor 1 to a high temperature and high pressure, and flows out from the outdoor unit 10 via the flow path switching valve 2. The refrigerant flowing out of the outdoor unit 10 flows into the indoor unit 20 through the connecting pipe 8 and flows into the indoor heat exchanger 5 through the first on-off valve 31 which is fully opened. The refrigerant flowing into the indoor heat exchanger 5 is condensed and liquefied by radiating heat to the surrounding air, that is, the indoor air in the indoor heat exchanger 5. At this time, the drive of the indoor fan 21 promotes heat exchange between the refrigerant and the air. The refrigerant flowing out of the indoor heat exchanger 5 flows out from the indoor unit 20 through the second on-off valve 32 which is fully opened. The refrigerant flowing out of the indoor unit 20 flows into the outdoor unit 10 through the connecting pipe 7, is decompressed by the expansion valve 4, expands, and flows into the outdoor heat exchanger 3. The refrigerant flowing into the outdoor heat exchanger 3 evaporates and gasifies by absorbing heat from the surrounding air, that is, the outside air in the outdoor heat exchanger 3. At this time, the drive of the outdoor fan 11 promotes heat exchange between the refrigerant and the air. The refrigerant flowing out of the outdoor heat exchanger 3 is sucked into the compressor 1 again through the flow path switching valve 2 and compressed. During the heating operation, the above cycle is repeated to heat the room.
　次に、冷房運転中に運転が停止されたときに制御装置５０が行う第一制御について説明する。図３は、低外気において冷房運転の停止時に制御装置が行う制御のフローチャートである。図４は、第一制御における各機器の動作を示す図である。 Next, the first control performed by the control device 50 when the operation is stopped during the cooling operation will be described. FIG. 3 is a flowchart of control performed by the control device when the cooling operation is stopped in low outside air. FIG. 4 is a diagram showing the operation of each device in the first control.
　空気調和機１００が冷房運転を実施しているとき、図１及び図４に示されるように、圧縮機１は運転し、流路切替弁２は冷房側とされ、第一開閉弁３１及び第二開閉弁３２は全開とされ、冷房運転時のサイクルで冷媒が冷媒回路１００ａを循環している。圧縮機１の周波数、膨張弁４の開度、室外ファン１１及び室内ファン２１は、室内の負荷及び設定に応じて制御装置５０により制御されている。 When the air conditioner 100 is performing the cooling operation, as shown in FIGS. 1 and 4, the compressor 1 is operated, the flow path switching valve 2 is on the cooling side, and the first on-off valve 31 and the first on-off valve 31 and the second (2) The on-off valve 32 is fully opened, and the refrigerant circulates in the refrigerant circuit 100a in the cycle during the cooling operation. The frequency of the compressor 1, the opening degree of the expansion valve 4, the outdoor fan 11 and the indoor fan 21 are controlled by the control device 50 according to the load and setting in the room.
　冷房運転中に冷房運転の停止の指令が入力されると、図３の制御が開始し、まず、運転停止の処理が行われる（ステップＳ１）。具体的には、室内ファン２１の運転及び室外ファン１１の運転が停止される。ここで図３の制御が開始するタイミングは、リモートコントローラを介して指令が入力されたときに限定されない。例えば、タイマー機能等により冷房運転の終了時刻が決められている場合には、終了時刻となったときに自動的に図３の制御が開始される。 When a command to stop the cooling operation is input during the cooling operation, the control shown in FIG. 3 is started, and the operation stop process is first performed (step S1). Specifically, the operation of the indoor fan 21 and the operation of the outdoor fan 11 are stopped. Here, the timing at which the control of FIG. 3 starts is not limited to the time when a command is input via the remote controller. For example, when the end time of the cooling operation is determined by the timer function or the like, the control of FIG. 3 is automatically started when the end time is reached.
　ステップＳ１の後、制御装置５０は、第一センサ４１で検出された外気温Ｔｏが、第二センサ４２で検出された室温Ｔｉ以下であるか否かを判定する（ステップＳ２）。外気温Ｔｏが室温Ｔｉよりも高い場合、制御装置５０は、外気温Ｔｏが室温Ｔｉ以下ではないと判定し（ステップＳ２；ＮＯ）、直ちに圧縮機１を停止させる（ステップＳ９）。圧縮機１が停止された後（ステップＳ９）、図３の制御が終了する。 After step S1, the control device 50 determines whether or not the outside air temperature To detected by the first sensor 41 is equal to or lower than the room temperature Ti detected by the second sensor 42 (step S2). When the outside air temperature To is higher than the room temperature Ti, the control device 50 determines that the outside air temperature To is not below the room temperature Ti (step S2; NO), and immediately stops the compressor 1 (step S9). After the compressor 1 is stopped (step S9), the control of FIG. 3 ends.
　一方、外気温Ｔｏが室温Ｔｉ以下であると判定された場合には（ステップＳ２；ＹＥＳ）、制御装置５０は、ステップＳ３～ステップＳ８の第一制御を行う。具体的には、制御装置５０は、まず、流路切替弁２を暖房側へ切り替え（ステップＳ３）、第二開閉弁３２を全閉し（ステップＳ４）、室内機２０への冷媒の貯留処理を開始する。 On the other hand, when it is determined that the outside air temperature To is room temperature Ti or less (step S2; YES), the control device 50 performs the first control of steps S3 to S8. Specifically, the control device 50 first switches the flow path switching valve 2 to the heating side (step S3), fully closes the second on-off valve 32 (step S4), and stores the refrigerant in the indoor unit 20. To start.
　図５は、第一制御の貯留処理が行われているときの冷媒回路の冷媒流れを示す説明図である。図５には、貯留処理の開始時における室外熱交換器３の冷媒量及び室内熱交換器５の冷媒量がそれぞれ斜線で模式的に示されている。図４に示されるように、貯留処理が実施されているとき、圧縮機１は運転される。図５に示されるように、圧縮機１から吐出された冷媒は、流路切替弁２、接続配管８、及び第一開閉弁３１を介して室内熱交換器５に流入し、全閉とされている第二開閉弁３２により室内機２０からの流出が塞き止められて、主に室内熱交換器５に貯留される。一方、室外機１０では、室内機２０から冷媒が戻らず、また室外熱交換器３に存在している冷媒は圧縮機１の運転により室外機１０から流出するので、室外熱交換器３の冷媒量は減少する。 FIG. 5 is an explanatory diagram showing the refrigerant flow of the refrigerant circuit when the first control storage process is being performed. In FIG. 5, the amount of refrigerant in the outdoor heat exchanger 3 and the amount of refrigerant in the indoor heat exchanger 5 at the start of the storage process are schematically shown by diagonal lines. As shown in FIG. 4, the compressor 1 is operated when the storage process is being carried out. As shown in FIG. 5, the refrigerant discharged from the compressor 1 flows into the indoor heat exchanger 5 via the flow path switching valve 2, the connection pipe 8, and the first on-off valve 31, and is fully closed. The second on-off valve 32 blocks the outflow from the indoor unit 20 and stores the heat mainly in the indoor heat exchanger 5. On the other hand, in the outdoor unit 10, the refrigerant does not return from the indoor unit 20, and the refrigerant existing in the outdoor heat exchanger 3 flows out from the outdoor unit 10 due to the operation of the compressor 1. Therefore, the refrigerant in the outdoor heat exchanger 3 The amount decreases.
　貯留処理が開始されて設定時間が経過すると、制御装置５０は、第三センサ４３で検出された室外熱交換器３の温度Ｔｈｅｘが、第一センサ４１で検出された外気温Ｔｏと同じであるか否かを判定する（ステップＳ５）。貯留処理が開始された直後、室外熱交換器３の温度Ｔｈｅｘは外気温Ｔｏ以下となっている。貯留処理が実施されているとき、図５に示されるサイクルにより室外機１０側の冷媒が室内機２０側に移動することにより、室外熱交換器３の冷媒量が減少する。このため、室外熱交換器３の伝熱管が外気により冷却され、室外熱交換器３の温度Ｔｈｅｘが次第に低下する。その後、室外熱交換器３の冷媒量が更に減少すると、室外熱交換器３の温度Ｔｈｅｘは更に低下して外気温Ｔｏと同等の温度になる。つまり、ステップＳ５の判定により、貯留処理が完了したか否かが判断される。 When the storage process is started and the set time elapses, the control device 50 has the same temperature Tex of the outdoor heat exchanger 3 detected by the third sensor 43 as the outside air temperature To detected by the first sensor 41. Whether or not it is determined (step S5). Immediately after the storage process is started, the temperature Thex of the outdoor heat exchanger 3 is equal to or lower than the outside air temperature To. When the storage process is being carried out, the amount of refrigerant in the outdoor heat exchanger 3 is reduced by moving the refrigerant on the outdoor unit 10 side to the indoor unit 20 side by the cycle shown in FIG. Therefore, the heat transfer tube of the outdoor heat exchanger 3 is cooled by the outside air, and the temperature Thex of the outdoor heat exchanger 3 gradually decreases. After that, when the amount of the refrigerant in the outdoor heat exchanger 3 further decreases, the temperature Thex of the outdoor heat exchanger 3 further decreases to the same temperature as the outside air temperature To. That is, the determination in step S5 determines whether or not the storage process is completed.
　ステップＳ５の判定において、室外熱交換器３の温度Ｔｈｅｘが外気温Ｔｏでないとき（ステップＳ５；ＮＯ）、貯留処理がまだ完了していないと判断され、制御装置５０は、予め決められた時間が経過したときにステップＳ５の判定を再度行う。室外熱交換器３の温度Ｔｈｅｘが外気温Ｔｏとなるまで、ステップＳ５の判定が繰り返される。室外熱交換器３の温度Ｔｈｅｘが外気温Ｔｏとなったとき（ステップＳ５；ＹＥＳ）、貯留処理が完了したと判断され、制御装置５０は、全開とされている第一開閉弁３１を全閉とし（ステップＳ６）、圧縮機１を停止させる（ステップＳ７）。 In the determination of step S5, when the temperature Thex of the outdoor heat exchanger 3 is not the outside air temperature To (step S5; NO), it is determined that the storage process has not been completed yet, and the control device 50 determines the predetermined time. When the elapse has passed, the determination in step S5 is performed again. The determination in step S5 is repeated until the temperature Thex of the outdoor heat exchanger 3 reaches the outside air temperature To. When the temperature Thex of the outdoor heat exchanger 3 reaches the outside air temperature To (step S5; YES), it is determined that the storage process is completed, and the control device 50 fully closes the first on-off valve 31, which is fully open. (Step S6), and the compressor 1 is stopped (step S7).
　図６は、図５の貯留処理の完了後に室内機に冷媒が封止された状態を示す冷媒回路図である。図６には、貯留処理の開始時における室外熱交換器３の冷媒量及び室内熱交換器５の冷媒量がそれぞれ斜線で模式的に示されている。図６に示されるように、第一開閉弁３１及び第二開閉弁３２が全閉とされると、貯留処理によって室内機２０側に貯留された冷媒の室外機１０側への流出が抑制され、室内機２０に冷媒が閉じ込められる。具体的には、冷媒回路１００ａにおいて、室内熱交換器５を含む、第一開閉弁３１と第二開閉弁３２との間の領域に冷媒が貯留される。このように、低外気環境下では、冷房運転が停止される際に上記の貯留処理が行われることにより、冷房運転の停止後、室内熱交換器５には、冷房運転が行われているときよりも多量の冷媒が存在することになる。 FIG. 6 is a refrigerant circuit diagram showing a state in which the refrigerant is sealed in the indoor unit after the storage process of FIG. 5 is completed. In FIG. 6, the amount of refrigerant in the outdoor heat exchanger 3 and the amount of refrigerant in the indoor heat exchanger 5 at the start of the storage process are schematically shown by diagonal lines. As shown in FIG. 6, when the first on-off valve 31 and the second on-off valve 32 are fully closed, the outflow of the refrigerant stored on the indoor unit 20 side to the outdoor unit 10 side by the storage process is suppressed. , The refrigerant is trapped in the indoor unit 20. Specifically, in the refrigerant circuit 100a, the refrigerant is stored in the region between the first on-off valve 31 and the second on-off valve 32, including the indoor heat exchanger 5. As described above, in a low outside air environment, the above storage process is performed when the cooling operation is stopped, so that the indoor heat exchanger 5 is performing the cooling operation after the cooling operation is stopped. There will be more refrigerant than.
　室内機２０に冷媒が封止され、ステップＳ７において圧縮機１の運転が停止された後、制御装置５０は、圧縮機１に拘束通電がされるようにインバータを制御する（ステップＳ８）。圧縮機１に拘束通電が行われた後、図３の制御が終了する。ここで、拘束通電とは、圧縮機モータを駆動することなくモータ巻線に通電を行うことであり、拘束通電によって圧縮機１を予備加熱することができる。拘束通電では、例えば、数ｋＨｚ以上の高周波交流電圧が圧縮機モータに出力される。 After the refrigerant is sealed in the indoor unit 20 and the operation of the compressor 1 is stopped in step S7, the control device 50 controls the inverter so that the compressor 1 is constrained and energized (step S8). After the compressor 1 is restrained and energized, the control of FIG. 3 ends. Here, the restraint energization means energizing the motor windings without driving the compressor motor, and the compressor 1 can be preheated by the restraint energization. In the restraint energization, for example, a high frequency AC voltage of several kHz or more is output to the compressor motor.
　なお、拘束通電が行われない場合、圧縮機１が運転を停止しているときには、圧縮機１を含む室外機１０は、外気により冷却されて外気温と同程度の温度になる。ここで、低外気環境下において空気調和機１００の冷房運転が開始された場合、冷媒は、室外機１０内を流れる間に冷却されて室内機２０に流入する。このため、冷房運転の開始時には特に低温の冷媒が室内機２０に流れ込むことにより、室内熱交換器５の伝熱管の表面温度が設定温度以下となり易く、凍結防止制御が機能して圧縮機１が停止される場合がある。 In addition, when the restraint energization is not performed, when the compressor 1 is stopped, the outdoor unit 10 including the compressor 1 is cooled by the outside air and becomes the same temperature as the outside air temperature. Here, when the cooling operation of the air conditioner 100 is started in a low outside air environment, the refrigerant is cooled while flowing in the outdoor unit 10 and flows into the indoor unit 20. Therefore, when the cooling operation is started, a particularly low temperature refrigerant flows into the indoor unit 20, so that the surface temperature of the heat transfer tube of the indoor heat exchanger 5 tends to be lower than the set temperature, and the antifreeze control functions to cause the compressor 1 to function. It may be stopped.
　そこで、本開示の空気調和機１００では、第一制御の一ステップとして圧縮機１の拘束通電が行われることで冷媒の温度低下を抑制し、冷房運転の開始時に凍結防止制御によって定常な冷房運転が妨げられてしまうことを防止している。圧縮機１の拘束通電が行われることにより、運転停止中において圧縮機１内に冷媒が溜まり込む冷媒寝込み現象の発生を防止することもできる。 Therefore, in the air conditioner 100 of the present disclosure, the temperature drop of the refrigerant is suppressed by performing the restraint energization of the compressor 1 as one step of the first control, and the cooling operation is constantly performed by the antifreeze control at the start of the cooling operation. Is prevented from being hindered. By performing the restraint energization of the compressor 1, it is possible to prevent the occurrence of the refrigerant stagnation phenomenon in which the refrigerant accumulates in the compressor 1 while the operation is stopped.
　次に、第一制御を伴って冷房運転が停止された後で冷房運転が再開されるときに制御装置５０が行う第二制御について説明する。図７は、低外気において冷房運転の開始時に制御装置が行う第二制御のフローチャートである。図８は、第二制御における各機器の動作を示す図である。 Next, the second control performed by the control device 50 when the cooling operation is restarted after the cooling operation is stopped with the first control will be described. FIG. 7 is a flowchart of the second control performed by the control device at the start of the cooling operation in low outside air. FIG. 8 is a diagram showing the operation of each device in the second control.
　貯留処理が行われた後で空気調和機１００が運転を停止しているとき、図６及び図８に示されるように、圧縮機１は停止し、流路切替弁２は冷房側とされ、第一開閉弁３１及び第二開閉弁３２は全閉とされ、室内機２０側に冷媒が封止された状態となっている。またこのとき、図８に示されるように、膨張弁４は閉とされ、室外ファン１１は停止されている。 When the air conditioner 100 is stopped in operation after the storage process is performed, the compressor 1 is stopped and the flow path switching valve 2 is set to the cooling side, as shown in FIGS. 6 and 8. The first on-off valve 31 and the second on-off valve 32 are fully closed, and the refrigerant is sealed on the indoor unit 20 side. At this time, as shown in FIG. 8, the expansion valve 4 is closed and the outdoor fan 11 is stopped.
　図７に示されるように、運転停止中に冷房運転の開始の指令が入力されると、図７の制御が開始し、室内機２０に貯留され封止されている冷媒を解放する解放処理が行われる。具体的には、制御装置５０は、運転開始の処理を行い（ステップＳ１１）、全閉とされている第一開閉弁３１を全開とし（ステップＳ１２）、閉とされている膨張弁４を全開とする（ステップＳ１３）。ステップＳ１１の運転開始処理では、圧縮機１が起動され、室内ファン２１が運転を開始する。ここで第二制御が開始するタイミングは、リモートコントローラを介して指令が入力されたときに限定されない。例えば、タイマー機能等により冷媒運転の開始時刻が決められている場合には、開始時刻となったときに自動的に第二制御が開示される。 As shown in FIG. 7, when a command for starting the cooling operation is input while the operation is stopped, the control in FIG. 7 is started, and a release process for releasing the refrigerant stored and sealed in the indoor unit 20 is performed. Will be done. Specifically, the control device 50 performs an operation start process (step S11), fully opens the first on-off valve 31 that is fully closed (step S12), and fully opens the closed expansion valve 4. (Step S13). In the operation start process of step S11, the compressor 1 is activated and the indoor fan 21 starts operation. Here, the timing at which the second control starts is not limited to the time when the command is input via the remote controller. For example, when the start time of the refrigerant operation is determined by the timer function or the like, the second control is automatically disclosed when the start time is reached.
　図９は、第二制御の解放処理が行われているときの冷媒回路の冷媒流れを示す説明図である。図９に示されるように、解放処理が実施されているとき、流路切替弁２は冷房側とされている。室内熱交換器５に貯留されている冷媒は、圧縮機１の運転により、全開とされている第一開閉弁３１及び接続配管８を介して室外機１０へ流入する。室内機２０から解放され室外機１０に流入した冷媒は、流路切替弁２を通過して圧縮機１に吸入され、圧縮されて室外熱交換器３に流入する。室外熱交換器３に流入した冷媒は、全開とされている膨張弁４を通り、接続配管７を介して室内機２０側へ流入しようとするが、全閉とされている第二開閉弁３２により室内熱交換器５への移動が塞き止められる。このため、冷房運転の開始時に、運転停止中に室外熱交換器３に存在していた低温の冷媒が直接、室内熱交換器５に流入してしまうことを回避できる。 FIG. 9 is an explanatory diagram showing the refrigerant flow of the refrigerant circuit when the release process of the second control is being performed. As shown in FIG. 9, when the release process is being carried out, the flow path switching valve 2 is on the cooling side. The refrigerant stored in the indoor heat exchanger 5 flows into the outdoor unit 10 through the first on-off valve 31 and the connecting pipe 8 which are fully opened by the operation of the compressor 1. The refrigerant released from the indoor unit 20 and flowing into the outdoor unit 10 passes through the flow path switching valve 2 and is sucked into the compressor 1, compressed and flows into the outdoor heat exchanger 3. The refrigerant flowing into the outdoor heat exchanger 3 tries to flow into the indoor unit 20 side through the expansion valve 4 which is fully opened and through the connection pipe 7, but the second on-off valve 32 which is fully closed. This prevents the movement to the indoor heat exchanger 5. Therefore, at the start of the cooling operation, it is possible to prevent the low-temperature refrigerant existing in the outdoor heat exchanger 3 while the operation is stopped from directly flowing into the indoor heat exchanger 5.
　また解放処理では、圧縮機１が運転される一方で室外ファン１１は停止されており、また膨張弁４が全開とされていることにより、接続配管７を含む、第二開閉弁３２の室外機１０側の冷媒配管に、圧縮機１から吐き出された冷媒が移動し易くなる。このため、解放処理が実施されているとき、第二開閉弁３２の室外機１０側の冷媒配管に存在する冷媒の温度が上昇する。 Further, in the release process, the outdoor fan 11 is stopped while the compressor 1 is operated, and the expansion valve 4 is fully opened, so that the outdoor unit of the second on-off valve 32 including the connection pipe 7 is operated. The refrigerant discharged from the compressor 1 can easily move to the refrigerant pipe on the 10 side. Therefore, when the release process is being performed, the temperature of the refrigerant existing in the refrigerant pipe on the outdoor unit 10 side of the second on-off valve 32 rises.
　上記の解放処理が開始された後、制御装置５０は、第三センサ４３で検出された室外熱交換器３の温度Ｔｈｅｘが、第一センサ４１で検出された外気温Ｔｏ以上であるか否かを判定する（ステップＳ１４）。室外熱交換器３の温度Ｔｈｅｘが外気温Ｔｏ未満である場合（ステップＳ１４；ＮＯ）、制御装置５０は、予め決められた時間が経過したときにステップＳ１４の判定を再度行う。室外熱交換器３の温度Ｔｈｅｘが外気温Ｔｏ以上となるまで、ステップＳ１４の判定が繰り返される。一方、室外熱交換器３の温度Ｔｈｅｘが外気温Ｔｏ以上となった場合には（ステップＳ１４；ＹＥＳ）、制御装置５０は、解放処理を終了するとともに通常の冷房運転を開始させる。具体的には、制御装置５０は、停止している室外ファン１１の運転を開始し（ステップＳ１５）、全閉とされている第二開閉弁３２を全開とする（ステップＳ１６）。ステップＳ１６の後、図７の制御が終了する。 After the release process is started, the control device 50 determines whether or not the temperature Tex of the outdoor heat exchanger 3 detected by the third sensor 43 is equal to or higher than the outside air temperature To detected by the first sensor 41. Is determined (step S14). When the temperature Thex of the outdoor heat exchanger 3 is less than the outside air temperature To (step S14; NO), the control device 50 re-determines step S14 when a predetermined time has elapsed. The determination in step S14 is repeated until the temperature Thex of the outdoor heat exchanger 3 becomes equal to or higher than the outside air temperature To. On the other hand, when the temperature Thex of the outdoor heat exchanger 3 becomes equal to or higher than the outside air temperature To (YES in step S14; YES), the control device 50 ends the release process and starts the normal cooling operation. Specifically, the control device 50 starts the operation of the stopped outdoor fan 11 (step S15), and fully opens the second on-off valve 32 that is fully closed (step S16). After step S16, the control of FIG. 7 ends.
　解放処理において第二開閉弁３２により塞き止められていた冷媒は、第二開閉弁３２が全開とされると、室内熱交換器５に流入する。ここで、室内熱交換器５に流入する冷媒は、解放処理の間に温度が上昇しているので、解放処理の終了後、冷房運転の開始時に、室内熱交換器５が極端に冷却されることが回避できる。よって、低外気環境下でも、冷房運転の開始時に凍結防止制御が機能することが回避でき、定常な冷房運転を行うことができる。 The refrigerant blocked by the second on-off valve 32 in the release process flows into the indoor heat exchanger 5 when the second on-off valve 32 is fully opened. Here, since the temperature of the refrigerant flowing into the indoor heat exchanger 5 rises during the release process, the indoor heat exchanger 5 is extremely cooled at the start of the cooling operation after the release process is completed. Can be avoided. Therefore, even in a low outside air environment, it is possible to prevent the antifreezing control from functioning at the start of the cooling operation, and it is possible to perform a steady cooling operation.
　その後、図１に示されるサイクルで冷媒が冷媒回路１００ａを循環する冷房運転が行われ、室内の負荷に応じて、圧縮機１の周波数、膨張弁４の開度、及び室外ファン１１の回転数が制御される。 After that, a cooling operation is performed in which the refrigerant circulates in the refrigerant circuit 100a in the cycle shown in FIG. 1, and the frequency of the compressor 1, the opening degree of the expansion valve 4, and the rotation speed of the outdoor fan 11 are performed according to the load in the room. Is controlled.
　以上のように、実施の形態１において空気調和機１００は、冷媒回路１００ａと、第一開閉弁３１と、第二開閉弁３２とを備える。第一開閉弁３１は、冷媒回路１００ａにおいて室内熱交換器５の出入口の一方と流路切替弁２との間に設けられ、室内機２０に配置されている。第二開閉弁３２は、冷媒回路１００ａにおいて室内熱交換器５の出入口の他方と膨張弁４との間に設けられ、室内機２０に配置されている。 As described above, in the first embodiment, the air conditioner 100 includes a refrigerant circuit 100a, a first on-off valve 31, and a second on-off valve 32. The first on-off valve 31 is provided between one of the inlet and outlet of the indoor heat exchanger 5 and the flow path switching valve 2 in the refrigerant circuit 100a, and is arranged in the indoor unit 20. The second on-off valve 32 is provided between the other of the inlet and outlet of the indoor heat exchanger 5 and the expansion valve 4 in the refrigerant circuit 100a, and is arranged in the indoor unit 20.
　これにより、第一開閉弁３１と第二開閉弁３２とにより、室内熱交換器５を含む室内機２０側の冷媒回路１００ａに冷媒を貯留させることができる。よって、低外気環境下でも運転停止時に外気温による冷媒温度の低下を抑制でき、冷房運転の再開時に凍結防止制御抑制が機能することが回避できるので、連続的に冷房運転を行うことができる。 As a result, the first on-off valve 31 and the second on-off valve 32 can store the refrigerant in the refrigerant circuit 100a on the indoor unit 20 side including the indoor heat exchanger 5. Therefore, even in a low outside air environment, it is possible to suppress a decrease in the refrigerant temperature due to the outside air temperature when the operation is stopped, and it is possible to prevent the antifreezing control suppression from functioning when the cooling operation is restarted, so that the cooling operation can be continuously performed.
　また空気調和機１００は、外気温Ｔｏを検出する第一センサ４１と、空調対象空間の室温を検出する第二センサ４２と、制御装置５０とを備える。制御装置５０は、冷房運転が停止する際に、第一センサ４１により検出された外気温Ｔｏが第二センサ４２により検出された室温Ｔｉ以下である場合に、流路切替弁２を切り替え、第二開閉弁３２を全閉とする制御を行う。このような制御により、低外気環境下において冷房運転の停止時に冷媒を室内機２０側へ移動させ貯留することが容易に実現できる。 Further, the air conditioner 100 includes a first sensor 41 that detects the outside air temperature To, a second sensor 42 that detects the room temperature of the air-conditioned space, and a control device 50. When the cooling operation is stopped, the control device 50 switches the flow path switching valve 2 when the outside air temperature To detected by the first sensor 41 is equal to or lower than the room temperature Ti detected by the second sensor 42. (Ii) Control is performed so that the on-off valve 32 is fully closed. With such control, it is possible to easily realize that the refrigerant is moved to the indoor unit 20 side and stored when the cooling operation is stopped in a low outside air environment.
　また空気調和機１００は、室外熱交換器３の温度Ｔｈｅｘを検出する第三センサ４３を更に備え、制御装置５０は、貯留処理を開始した後で、室外熱交換器３の温度Ｔｈｅｘが外気温Ｔｏと一致した場合に、第一開閉弁３１を全閉とする制御を行う。これにより、貯留処理によって室内機２０側に移動し貯留された冷媒の流出を防ぎ、運転が停止している間、室内機２０に冷媒を封止しておくことができる。 Further, the air conditioner 100 further includes a third sensor 43 that detects the temperature Tex of the outdoor heat exchanger 3, and the control device 50 further starts the storage process, and then the temperature Tex of the outdoor heat exchanger 3 changes to the outside air temperature. When it matches with To, the first on-off valve 31 is controlled to be fully closed. As a result, it is possible to prevent the outflow of the stored refrigerant that has moved to the indoor unit 20 side by the storage process and to keep the refrigerant sealed in the indoor unit 20 while the operation is stopped.
　また制御装置５０は、第一開閉弁３１を全閉とすることにより貯留処理を終了した後、圧縮機１を停止し、圧縮機１に拘束通電がされるように制御を行う。これにより、圧縮機１を予備加熱し、室外機１０側に存在する冷媒の外気による温度低下を遅らせることができる。よって、冷房運転の再開時に室内機２０へ流入する冷媒の、運転停止中における温度低下を最小限とでき、定常な冷房運転を行うことができるという効果を更に高めることができる。また拘束通電により、運転停止中の冷媒寝込み現象の発生を抑制することができる。 Further, the control device 50 stops the compressor 1 after completing the storage process by fully closing the first on-off valve 31, and controls the compressor 1 so as to be restrained and energized. As a result, the compressor 1 can be preheated, and the temperature drop of the refrigerant existing on the outdoor unit 10 side due to the outside air can be delayed. Therefore, the temperature drop of the refrigerant flowing into the indoor unit 20 when the cooling operation is restarted can be minimized while the operation is stopped, and the effect that the steady cooling operation can be performed can be further enhanced. Further, by restraining energization, it is possible to suppress the occurrence of the refrigerant sneaking phenomenon during the operation stop.
　また制御装置５０は、外気温Ｔｏが室温Ｔｉ以下であるときに冷房運転が停止した後において冷房運転が再開する際に、圧縮機１を起動し、第一開閉弁３１を全開とし、膨張弁４を全開とするように制御を行う。室内機２０に配置されている第一開閉弁３１と第二開閉弁３２とが、制御装置５０によりこのように動作することで、運転停止時に室外熱交換器３で外気により冷却された冷媒がそのままの温度で室内機２０に流入することが防止できる。また、冷房運転の再開時に室内機２０に流入する冷媒の温度を高くすることができるので、冷房運転時のサイクルにおいて蒸発温度の低下を防ぐことができる。 Further, the control device 50 starts the compressor 1 and fully opens the first on-off valve 31 to fully open the expansion valve when the cooling operation is restarted after the cooling operation is stopped when the outside air temperature To is room temperature Ti or less. Control is performed so that 4 is fully opened. The first on-off valve 31 and the second on-off valve 32 arranged in the indoor unit 20 operate in this way by the control device 50, so that the refrigerant cooled by the outside air in the outdoor heat exchanger 3 when the operation is stopped is released. It is possible to prevent the indoor unit 20 from flowing into the indoor unit 20 at the same temperature. Further, since the temperature of the refrigerant flowing into the indoor unit 20 can be raised when the cooling operation is restarted, it is possible to prevent the evaporation temperature from decreasing in the cycle during the cooling operation.
　制御装置５０は、貯留処理を行って空気調和機１００の運転が停止した後に冷房運転を再開する際に、解放処理を開始した後、室外熱交換器３の温度Ｔｈｅｘが外気温Ｔｏ以上である場合に、第二開閉弁３２を全開とする制御を行う。これにより、冷房運転の再開時に室内熱交換器５に流入する冷媒の温度を一定温度以上とすることができ、上記の効果を更に高めることができる。 When the control device 50 restarts the cooling operation after the storage process is performed and the operation of the air conditioner 100 is stopped, the temperature Thex of the outdoor heat exchanger 3 is equal to or higher than the outside air temperature To after the release process is started. In this case, the second on-off valve 32 is controlled to be fully opened. As a result, the temperature of the refrigerant flowing into the indoor heat exchanger 5 when the cooling operation is restarted can be set to a certain temperature or higher, and the above effect can be further enhanced.
　なお、上記の実施の形態を適宜、変形又は省略することが可能である。例えば、圧縮機１を制御する制御装置５０が、第一開閉弁３１及び第二開閉弁３２を制御する機能を兼ねるものとしたが、第一開閉弁３１及び第二開閉弁３２を制御する制御基板を制御装置５０とは別に設ける構成としてもよい。この場合、制御基板と制御装置５０とは電気的に接続される。 Note that the above embodiment can be appropriately modified or omitted. For example, the control device 50 that controls the compressor 1 also has a function of controlling the first on-off valve 31 and the second on-off valve 32, but controls that control the first on-off valve 31 and the second on-off valve 32. The substrate may be provided separately from the control device 50. In this case, the control board and the control device 50 are electrically connected.
　また、上記の実施の形態では、第一制御に圧縮機１に対する拘束通電のステップが含まれるものとして説明したが、拘束通電は省略できる。また空気調和機１００は、運転停止中、予め決められたタイミングで拘束通電を行う構成とすることもできる。 Further, in the above embodiment, it has been described that the first control includes the step of restraint energization for the compressor 1, but the restraint energization can be omitted. Further, the air conditioner 100 may be configured to perform restraint energization at a predetermined timing while the operation is stopped.
　１　圧縮機、２　流路切替弁、３　室外熱交換器、４　膨張弁、５　室内熱交換器、７、８　接続配管、１０　室外機、１１　室外ファン、２０　室内機、２１　室内ファン、２７、２８　室内配管、３１　第一開閉弁、３２　第二開閉弁、４１　第一センサ、４２　第二センサ、４３　第三センサ、４４　第四センサ、５０　制御装置、５１　入力部、５２　主制御部、５３　記憶部、１００　空気調和機、１００ａ　冷媒回路、Ｔｈｅｘ　室外熱交換器の温度、Ｔｉ　室温、Ｔｏ　外気温。 1 Compressor, 2 Flow path switching valve, 3 Outdoor heat exchanger, 4 Expansion valve, 5 Indoor heat exchanger, 7, 8 Connection piping, 10 Outdoor unit, 11 Outdoor fan, 20 Indoor unit, 21 Indoor fan, 27, 28 Indoor piping, 31 1st on-off valve, 32 2nd on-off valve, 41 1st sensor, 42 2nd sensor, 43 3rd sensor, 44 4th sensor, 50 control device, 51 input unit, 52 main control unit, 53 Storage unit, 100 air conditioner, 100a refrigerant circuit, The temperature of the outdoor heat exchanger, Ti room temperature, To outside temperature.

Claims (7)

  1. 　空調対象空間に設置される室内機と、室外機とが接続された空気調和機において、
    　圧縮機と、流路切替弁と、室外熱交換器と、膨張弁と、室内熱交換器と、が冷媒配管により接続された冷媒回路と、
    　前記冷媒回路において前記室内熱交換器の出入口の一方と前記流路切替弁との間に設けられ、前記室内機に配置された第一開閉弁と、
    　前記冷媒回路において前記室内熱交換器の前記出入口の他方と前記膨張弁との間に設けられ、前記室内機に配置された第二開閉弁と、
    　を備える空気調和機。     In an air conditioner in which an indoor unit installed in an air-conditioned space and an outdoor unit are connected,
    A refrigerant circuit in which a compressor, a flow path switching valve, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger are connected by a refrigerant pipe.
    In the refrigerant circuit, a first on-off valve provided between one of the inlet / outlet of the indoor heat exchanger and the flow path switching valve and arranged in the indoor unit, and a first on-off valve.
    In the refrigerant circuit, a second on-off valve provided between the other of the inlet / outlet of the indoor heat exchanger and the expansion valve and arranged in the indoor unit, and a second on-off valve.
    Air conditioner equipped with.
  2. 　外気温を検出する第一センサと、
    　前記空調対象空間の室温を検出する第二センサと、
    　前記室外熱交換器が凝縮器として機能し、前記室内熱交換器が蒸発器として機能する冷房運転が停止する際に、前記第一センサにより検出された前記外気温が前記第二センサにより検出された前記室温以下である場合に、前記流路切替弁を切り替え、前記第二開閉弁を全閉とする制御を行う制御装置と、を備えた
    　請求項１に記載の空気調和機。     The first sensor that detects the outside temperature and
    A second sensor that detects the room temperature of the air-conditioned space,
    When the outdoor heat exchanger functions as a condenser and the cooling operation in which the indoor heat exchanger functions as an evaporator is stopped, the outside temperature detected by the first sensor is detected by the second sensor. The air conditioner according to claim 1, further comprising a control device for switching the flow path switching valve and fully closing the second on-off valve when the temperature is below room temperature.
  3. 　前記室外熱交換器の温度を検出する第三センサを更に備え、
    　前記制御装置は、前記冷房運転が停止する際に前記流路切替弁を切り替え、前記第二開閉弁を全閉とする制御を行った後、前記第三センサにより検出された前記室外熱交換器の温度が前記第一センサにより検出された前記外気温と一致した場合に、前記第一開閉弁を全閉とする制御を行う
    　請求項２に記載の空気調和機。     Further equipped with a third sensor for detecting the temperature of the outdoor heat exchanger,
    The control device switches the flow path switching valve when the cooling operation is stopped, controls the second on-off valve to be fully closed, and then detects the outdoor heat exchanger by the third sensor. The air conditioner according to claim 2, wherein when the temperature of the first on-off valve matches the outside air temperature detected by the first sensor, the first on-off valve is controlled to be fully closed.
  4. 　前記制御装置は、前記冷房運転が停止する際に前記第一開閉弁を全閉とする制御を行った後、前記圧縮機を停止し、前記圧縮機に拘束通電がされるように制御を行う
    　請求項３に記載の空気調和機。     The control device controls to fully close the first on-off valve when the cooling operation is stopped, then stops the compressor, and controls so that the compressor is restrained and energized. The air conditioner according to claim 3.
  5. 　前記制御装置は、前記外気温が前記室温以下であるときに前記冷房運転が停止した後において前記冷房運転が再開する際に、前記圧縮機を起動し、前記第一開閉弁を全開とし、前記膨張弁を全開とするように制御を行う
    　請求項３又は４に記載の空気調和機。     The control device activates the compressor and fully opens the first on-off valve when the cooling operation is restarted after the cooling operation is stopped when the outside air temperature is equal to or lower than the room temperature. The air conditioner according to claim 3 or 4, wherein the expansion valve is controlled to be fully opened.
  6. 　前記制御装置は、前記外気温が前記室温以下であるときに前記冷房運転が停止した後において前記冷房運転が再開する際に、前記圧縮機を起動し、前記第一開閉弁を全開とし、前記膨張弁を全開とするように制御した後、前記第三センサにより検出された前記室外熱交換器の温度が前記第一センサにより検出された前記外気温以上である場合に、前記第二開閉弁を全開とする制御を行う
    　請求項５に記載の空気調和機。     The control device activates the compressor and fully opens the first on-off valve when the cooling operation is restarted after the cooling operation is stopped when the outside air temperature is equal to or lower than the room temperature. After controlling the expansion valve to be fully opened, when the temperature of the outdoor heat exchanger detected by the third sensor is equal to or higher than the outside air temperature detected by the first sensor, the second on-off valve is used. The air conditioner according to claim 5, wherein the air conditioner is controlled to be fully opened.
  7. 　前記室外熱交換器に送風する室外ファンを更に備え、
    　前記制御装置は、前記外気温が前記室温以下であるときに前記冷房運転が停止した後において前記冷房運転が再開する際に、前記圧縮機を起動し、前記第一開閉弁を全開とし、前記膨張弁を全開とするように制御した後、前記第二開閉弁を全開とすると同時又は全開とした後に、前記室外ファンの運転を開始するように制御を行う
    　請求項６に記載の空気調和機。     Further equipped with an outdoor fan that blows air to the outdoor heat exchanger,
    The control device activates the compressor and fully opens the first on-off valve when the cooling operation is restarted after the cooling operation is stopped when the outside air temperature is equal to or lower than the room temperature. The air conditioner according to claim 6, wherein the expansion valve is controlled to be fully opened, and then the second on-off valve is simultaneously or fully opened, and then the outdoor fan is controlled to start operation. ..
PCT/JP2020/013900 2020-03-27 2020-03-27 Air conditioner WO2021192195A1 (en)

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JPS5923065U (en) * 1982-08-04 1984-02-13 株式会社東芝 air conditioner
JPH09145191A (en) * 1995-11-24 1997-06-06 Sanyo Electric Co Ltd Air conditioner
JP2000179958A (en) * 1998-12-16 2000-06-30 Matsushita Electric Ind Co Ltd Air conditioner
JP2005221167A (en) * 2004-02-06 2005-08-18 Mitsubishi Electric Corp Air conditioner
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US20140123685A1 (en) * 2012-11-02 2014-05-08 Jeonghun Kim Air conditioner and a method of controlling an air conditioner
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5923065U (en) * 1982-08-04 1984-02-13 株式会社東芝 air conditioner
JPH09145191A (en) * 1995-11-24 1997-06-06 Sanyo Electric Co Ltd Air conditioner
JP2000179958A (en) * 1998-12-16 2000-06-30 Matsushita Electric Ind Co Ltd Air conditioner
JP2005221167A (en) * 2004-02-06 2005-08-18 Mitsubishi Electric Corp Air conditioner
JP2010164270A (en) * 2009-01-19 2010-07-29 Panasonic Corp Multiple chamber type air conditioner
US20140123685A1 (en) * 2012-11-02 2014-05-08 Jeonghun Kim Air conditioner and a method of controlling an air conditioner
WO2018037466A1 (en) * 2016-08-22 2018-03-01 三菱電機株式会社 Refrigeration cycle device

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