WO2024166276A1 - Dispositif de climatisation - Google Patents

Dispositif de climatisation Download PDF

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Publication number
WO2024166276A1
WO2024166276A1 PCT/JP2023/004284 JP2023004284W WO2024166276A1 WO 2024166276 A1 WO2024166276 A1 WO 2024166276A1 JP 2023004284 W JP2023004284 W JP 2023004284W WO 2024166276 A1 WO2024166276 A1 WO 2024166276A1
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WIPO (PCT)
Prior art keywords
refrigerant
heat exchanger
detection unit
heat source
flow rate
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PCT/JP2023/004284
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English (en)
Japanese (ja)
Inventor
信太朗 増井
万誉 篠崎
祐治 本村
Original Assignee
三菱電機株式会社
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Priority to PCT/JP2023/004284 priority Critical patent/WO2024166276A1/fr
Publication of WO2024166276A1 publication Critical patent/WO2024166276A1/fr

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B1/00—Compression machines, plants or systems with non-reversible cycle
    • 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
    • F25B39/00—Evaporators; Condensers
    • F25B39/02—Evaporators
    • 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
    • F25B41/40—Fluid line arrangements
    • F25B41/42—Arrangements for diverging or converging flows, e.g. branch lines or junctions
    • F25B41/45—Arrangements for diverging or converging flows, e.g. branch lines or junctions for flow control on the upstream side of the diverging point, e.g. with spiral structure for generating turbulence

Definitions

  • This disclosure relates to air conditioners that use a refrigeration cycle to perform heating and cooling, and in particular to the control of a flow control valve installed in an indoor unit.
  • An air conditioner that uses a refrigeration cycle is equipped with a refrigerant circuit through which a refrigerant flows, which is formed by connecting a heat source unit having a compressor and a heat source side heat exchanger to an indoor unit having a flow control valve (hereinafter also referred to as a load side flow control valve) and a load side heat exchanger by piping.
  • a flow control valve hereinafter also referred to as a load side flow control valve
  • a load side heat exchanger a load side heat exchanger
  • SC target control when controlling the condensation capacity of the load side heat exchanger during heating, some perform SC target control, which adjusts the opening of the load side flow control valve using the degree of subcooling as a control parameter (see, for example, Patent Document 1).
  • the degree of subcooling is the difference between the condensing temperature and the refrigerant temperature at the outlet of the load side heat exchanger, which is the condenser.
  • SC target control the load side flow control valve is controlled so that the degree of subcooling of the refrigerant at the outlet of the load side heat exchanger, which is the condenser, becomes a predetermined target value.
  • SC target control when SC target control is performed, refrigerant that has a sufficient degree of subcooling at the outlet of the load side heat exchanger flows into the heat source side heat exchanger.
  • the load-side flow control valve is controlled using the degree of subcooling of the refrigerant at the outlet of the load-side heat exchanger (condenser) as a control parameter during heating
  • the dryness of the refrigerant flowing into the heat-source-side heat exchanger (evaporator) tends to be low.
  • the flow rate of a gaseous fluid is faster than that of a liquid-state fluid, mainly due to the difference in density.
  • the flow rate of the refrigerant slows down.
  • the flow rate of the refrigerant at the inlet of the heat-source-side heat exchanger becomes extremely slow due to the decrease in both the dryness of the refrigerant and the amount of circulating refrigerant. Therefore, the refrigerant cannot be distributed evenly from the distribution header provided at the inlet of the heat-source-side heat exchanger to each refrigerant path, and the refrigerant distribution performance of the heat-source-side heat exchanger may be extremely reduced.
  • This disclosure was made against the background of the above-mentioned problems, and provides an air conditioner that improves the refrigerant distribution performance of the heat source side heat exchanger during low load heating operation.
  • the air conditioning device includes a compressor that compresses and discharges a refrigerant, a load-side heat exchanger that functions as a condenser during heating operation, a flow control valve that adjusts the flow rate of the refrigerant flowing out of the load-side heat exchanger during the heating operation, a heat-source-side heat exchanger that functions as an evaporator during the heating operation, and a control unit that controls the opening of the flow control valve, and the control unit adjusts the opening of the load-side flow control valve during the heating operation using the dryness of the refrigerant flowing into the heat-source-side heat exchanger as a control parameter.
  • the opening of the load side flow control valve is adjusted using the dryness of the refrigerant flowing into the heat source side heat exchanger, which is the evaporator, as a control parameter.
  • the decrease in dryness of the refrigerant flowing into the heat source side heat exchanger is reduced, thereby reducing the decrease in the flow rate of the refrigerant. Therefore, it is possible to provide an air conditioning device with improved refrigerant distribution performance of the heat source side heat exchanger during low load heating operation.
  • FIG. 1 is a circuit diagram showing an air conditioning apparatus according to an embodiment of the present disclosure.
  • 2 is a block diagram showing functions of a control unit of an air conditioning apparatus according to an embodiment of the present disclosure.
  • FIG. 1 is a circuit diagram showing a state during full cooling operation of an air conditioning apparatus according to an embodiment of the present disclosure.
  • 1 is a circuit diagram showing a state during full heating operation of an air conditioning apparatus according to an embodiment of the present disclosure.
  • 1 is a circuit diagram showing a state during cooling-dominant operation of an air-conditioning apparatus according to an embodiment of the present disclosure.
  • 1 is a circuit diagram showing a state during heating-dominant operation of an air-conditioning apparatus according to an embodiment of the present disclosure.
  • FIG. 4 is a flowchart showing a method for adjusting the opening degree of a load-side flow control valve by a control unit of an air-conditioning apparatus according to an embodiment of the present disclosure.
  • 1 is a ph diagram showing an example of a change in the refrigerant state when the opening degree of a load side flow control valve is adjusted in an air conditioning apparatus according to an embodiment of the present disclosure.
  • FIG. 1 is a circuit diagram showing an air conditioner 1 according to an embodiment of the present disclosure.
  • the air conditioner 1 will be described based on FIG. 1.
  • the air conditioner 1 includes a heat source unit 100, a plurality of indoor units 300a and 300b, a relay unit 200 that distributes refrigerant supplied from the heat source unit 100 to the plurality of indoor units 300a and 300b, and a control unit 10.
  • the number of heat source units 100 and the number of indoor units included in the air conditioning device 1 are not limited to the above numbers.
  • the number of heat source units 100 may be two or more, and the number of indoor units may be three or more.
  • the relay unit 200 can perform cooling or heating operation for each indoor unit, but the relay unit 200 may be configured so that all of the indoor units 30 and 300b perform the same operation.
  • the air conditioning device 1 may not have a relay unit 200, and may have a configuration in which one indoor unit is connected to one heat source unit 100.
  • the air conditioning device 1 is configured by connecting a heat source unit 100, indoor units 300a and 300b, and a relay unit 200.
  • the heat source unit 100 has a function of supplying hot or cold heat to the two indoor units 300a and 300b.
  • the two indoor units 300a and 300b are connected in parallel to each other and have the same configuration.
  • the indoor units 300a and 300b may not be distinguished from each other and may be referred to as the indoor units 300.
  • the indoor unit 300 has a function of cooling or heating a space to be air-conditioned, such as a room, by using the hot or cold heat supplied from the heat source unit 100.
  • the relay unit 200 is interposed between the heat source unit 100 and the multiple indoor units 300a and 300b, and has a function of switching the flow of the refrigerant supplied from the heat source unit 100 in response to a request from each indoor unit 300.
  • the air conditioning device 1 also includes a load capacity detection unit 20 that detects the cooling and heating load capacities of the multiple indoor units 300a and 300b.
  • the cooling and heating load capacities refer to the cooling load capacity and heating load capacity of the multiple indoor units 300a and 300b.
  • the load capacity detection unit 20 includes multiple liquid pipe temperature detection units 303a and 303b, and multiple gas pipe temperature detection units 304a and 304b.
  • the heat source unit 100 and the relay unit 200 are connected on the high pressure side by a high pressure pipe 402 through which a high pressure refrigerant flows, and on the low pressure side by a low pressure pipe 401 through which a low pressure refrigerant flows.
  • the relay unit 200 and each indoor unit 300a, 300b are connected by gas branch pipes 403a, 403b, respectively. Refrigerant mainly in a gas state flows through the gas branch pipes 403a, 403b.
  • the relay unit 200 and each indoor unit 300a, 300b are connected by liquid branch pipes 404a, 404b, respectively. Refrigerant mainly in a liquid state flows through the liquid branch pipes 404a, 404b.
  • the heat source device 100 includes a variable capacity compressor 101, a flow path switching valve 102 that switches the direction of refrigerant flow in the heat source device 100, a heat source side heat exchange unit 120, an accumulator 104 that is connected to the suction side of the compressor 101 via the flow path switching valve 102 and stores liquid refrigerant, and a heat source side flow path adjustment unit 140 that limits the direction of refrigerant flow.
  • the heat source device 100 has a function of supplying hot or cold heat to the indoor units 300a and 300b. Note that, although FIG. 1 illustrates an example in which the flow path switching valve 102 is a four-way valve, the flow path switching valve 102 may be configured by combining two-way valves or three-way valves, etc.
  • the heat source side heat exchange unit 120 includes a main pipe 114, a heat source side heat exchanger 103, a heat source side blower 112, a bypass pipe 113, a heat source side flow control valve 109, a bypass flow control valve 110, and a gas-liquid separation section 111.
  • the heat source side heat exchanger 103 functions as an evaporator or a condenser. In the case of an air-cooled type, the heat source side heat exchanger 103 exchanges heat between the refrigerant and outdoor air, and in the case of a water-cooled type, the heat source side heat exchanger 103 exchanges heat between the refrigerant and water or brine, etc. Although not shown, the heat source side heat exchanger 103 has, for example, multiple heat transfer tubes and a header to which the ends of the multiple heat transfer tubes are connected.
  • the header that serves as the refrigerant inlet functions as a distribution header that distributes the refrigerant returned from the indoor units 300a and 300b to the heat source unit 100 to multiple heat transfer tubes (i.e., multiple refrigerant paths).
  • the heat source side blower 112 controls the heat exchange capacity by changing the amount of air blown to the heat source side heat exchanger 103.
  • One end of the main pipe 114 is connected to the flow path switching valve 102, and the other end is connected to the high-pressure pipe 402.
  • the main pipe 114 is provided with a heat source side heat exchanger 103 and a heat source side flow rate adjustment valve 109.
  • bypass pipe 113 One end of the bypass pipe 113 is connected to the flow path switching valve 102, and the other end is connected to the high-pressure pipe 402, and is connected in parallel to the main pipe 114.
  • the refrigerant flowing through the bypass pipe 113 does not pass through the heat source side heat exchanger 103, and is not heat exchanged in the heat source side heat exchanger 103.
  • the heat source side flow rate control valve 109 is connected in series to the heat source side heat exchanger 103 in the main pipe 114, and adjusts the flow rate of the refrigerant flowing in the main pipe 114. More specifically, the heat source side flow rate control valve 109 is provided between the heat source side heat exchanger 103 and the gas-liquid separation section 111 in the main pipe 114.
  • the piping section between the heat source side heat exchanger 103 and the heat source side flow rate control valve 109 in the main pipe 114 may be referred to as the first refrigerant piping 501.
  • the heat source side flow rate control valve 109 is, for example, an electric expansion valve with a variable opening.
  • the bypass flow rate control valve 110 is provided in the bypass pipe 113, and adjusts the flow rate of the refrigerant flowing in the bypass pipe 113.
  • the bypass flow rate control valve 110 is, for example, an electric expansion valve with a variable opening.
  • the gas-liquid separation unit 111 separates the refrigerant in a liquid state from the refrigerant in a gas state, and the main pipe 114 is connected to the liquid passing side through which the refrigerant in a liquid state passes, the bypass pipe 113 is connected to the gas passing side through which the refrigerant in a gas state passes, and the low-pressure pipe 401 and the high-pressure pipe 402 are connected to the mixing side through which the refrigerant in a liquid state and the refrigerant in a gas state pass.
  • the gas-liquid separation unit 111 merges the refrigerant flowing in the main pipe 114 and the refrigerant flowing in the bypass pipe 113 and flows them out into the high-pressure pipe 402, and when the refrigerant flows in from the low-pressure pipe 401, it branches the refrigerant flowing in from the low-pressure pipe 401 into the refrigerant flowing in the main pipe 114 and the refrigerant flowing in the bypass pipe 113.
  • the gas-liquid separation unit 111 may be configured, for example, as a T-shaped pipe, or may be configured as a pipe with a processed connection so that the gaseous refrigerant can be easily removed.
  • the gas-liquid separation unit 111 may be configured so that the efficiency of separating the gaseous refrigerant and the liquid refrigerant is 100%, or may be configured so that the efficiency is less than 100%, and it is sufficient that the shape is such that the separation efficiency meets the required specifications of the product.
  • Indoor units 300a and 300b are each provided with gas pipe temperature detection units 304a, 304b, liquid pipe temperature detection units 303a, 303b, and suction temperature detection units 305a, 305b.
  • gas pipe temperature detection unit 304a and gas pipe temperature detection unit 304b may not be distinguished from each other and each may be simply referred to as gas pipe temperature detection unit 304.
  • liquid pipe temperature detection unit 303a and liquid pipe temperature detection unit 303b may not be distinguished from each other and each may be simply referred to as liquid pipe temperature detection unit 303.
  • suction temperature detection unit 305a and suction temperature detection unit 305b may not be distinguished from each other and each may be simply referred to as suction temperature detection unit 305.
  • the liquid pipe temperature detection units 303a and 303b are provided between the load side heat exchangers 301a and 301b and the load side flow rate control valves 302a and 302b, respectively, and detect the temperature of the refrigerant flowing through the liquid branch pipes 404a and 404b that connect the load side heat exchangers 301a and 301b and the load side flow rate control valves 302a and 302b.
  • the piping section between the load side heat exchangers 301a and 301b and the load side flow rate control valves 302a and 302b in the liquid branch pipes 404a and 404b may be referred to as the second refrigerant piping 502a and 502b.
  • the intake temperature detection units 305a, 305b are provided, for example, in the housings of the indoor units 300a and 300b, respectively, and detect the temperature of the indoor air being drawn into the housings.
  • the intake temperature detection units 305a, 305b are composed of, for example, a thermistor, and transmit a signal of the detected temperature to the control unit 10.
  • the intake temperature detection units 305a, 305b may also have a storage device, etc. In this case, the intake temperature detection units 305a, 305b accumulate data of the detected temperature in the storage device, etc. for a predetermined period, and transmit a signal including the detected temperature data to the control unit 10 at predetermined intervals.
  • the relay unit 200 includes a first branch section 240, a second branch section 250, a gas-liquid separator 201, a relay bypass piping 209, a liquid outlet flow control valve 204, a heat exchange section 260, and a relay bypass flow control valve 205.
  • the relay unit 200 is interposed between the heat source unit 100 and the indoor units 300a and 300b, and has the function of switching the flow of refrigerant supplied from the heat source unit 100 in response to requests from the indoor units 300a and 300b, and distributing the refrigerant supplied from the heat source unit 100 to the multiple indoor units 300a and 300b.
  • the first branch 240 is connected at one end to the gas branch pipes 403a and 403b and at the other end to the low pressure pipe 401 and the high pressure pipe 402, and the refrigerant flows in different directions during cooling and heating operations.
  • the first branch 240 is equipped with heating solenoid valves 202a and 202b and cooling solenoid valves 203a and 203b.
  • the heating solenoid valves 202a and 202b are connected at one end to the gas branch pipes 403a and 403b and at the other end to the high pressure pipe 402, and are opened during heating operation and closed during cooling operation.
  • the cooling solenoid valves 203a and 203b are connected at one end to the gas branch pipes 403a and 403b and at the other end to the low pressure pipe 401, and are opened during cooling operation and closed during heating operation.
  • the second check valves 211a, 211b are connected at one end to the liquid branch pipes 404a, 404b and at the other end to the low-pressure pipe 401, allowing the flow of refrigerant from the liquid branch pipes 404a, 404b toward the high-pressure pipe 402.
  • the gas-liquid separator 201 separates refrigerant in a gaseous state from refrigerant in a liquid state, and has an inlet side connected to a high-pressure pipe 402, a gas outlet side connected to a first branch 240, and a liquid outlet side connected to a second branch 250.
  • the relay bypass piping 209 connects the second branch 250 to the low-pressure pipe 401.
  • the liquid outlet flow control valve 204 is connected to the liquid outlet side of the gas-liquid separator 201, and is composed of, for example, an electric expansion valve with a variable opening. The liquid outlet flow control valve 204 adjusts the flow rate of the liquid refrigerant flowing out of the gas-liquid separator 201.
  • the heat exchange section 260 is composed of a first heat exchange section 206 and a second heat exchange section 207.
  • the first heat exchange section 206 is provided between the liquid outflow side of the gas-liquid separator 201 and the liquid outflow side flow rate control valve 204, and in the relay bypass piping 209.
  • the first heat exchange section 206 exchanges heat between the liquid refrigerant flowing out of the gas-liquid separator 201 and the refrigerant flowing in the relay bypass piping 209.
  • the second heat exchange section 207 is provided downstream of the liquid outflow side flow rate control valve 204 and in the relay bypass piping 209.
  • the second heat exchange section 207 exchanges heat between the refrigerant flowing out of the liquid outflow side flow rate control valve 204 and the refrigerant flowing in the relay bypass piping 209.
  • the relay bypass flow rate control valve 205 is connected to the relay bypass piping 209 upstream of the second heat exchange section 207, and is configured, for example, with an electric expansion valve with a variable opening.
  • the relay bypass flow rate control valve 205 adjusts the flow rate of the refrigerant that flows out of the second heat exchange section 207 and flows into the relay bypass piping 209.
  • the relay unit 200 is also provided with a liquid outflow pressure detection unit 231, a downstream liquid outflow pressure detection unit 232, and a relay bypass temperature detection unit 208.
  • the liquid outflow pressure detection unit 231 is provided between the first heat exchange unit 206 and the upstream side of the liquid outflow side flow rate adjustment valve 204, and detects the pressure of the refrigerant on the liquid outflow side of the gas-liquid separator 201.
  • the liquid outflow pressure detection unit 231 is composed of, for example, a sensor, and transmits a signal of the detected pressure to the control unit 10.
  • the liquid outflow pressure detection unit 231 may also have a storage device, etc. In this case, the liquid outflow pressure detection unit 231 accumulates data of the detected pressure in the storage device, etc. for a predetermined period, and transmits a signal including data of the detected pressure at predetermined intervals to the control unit 10.
  • the downstream liquid outflow pressure detection unit 232 is provided between the downstream side of the liquid outflow side flow rate adjustment valve 204 and the second heat exchange unit 207, and detects the pressure of the refrigerant flowing out from the liquid outflow side flow rate adjustment valve 204.
  • the downstream liquid outflow pressure detection unit 232 is composed of, for example, a sensor, and transmits a signal of the detected pressure to the control unit 10.
  • the downstream liquid outflow pressure detection unit 232 may have a storage device, etc. In this case, the downstream liquid outflow pressure detection unit 232 accumulates the detected pressure data in the storage device, etc. for a predetermined period, and transmits a signal including the detected pressure data to the control unit 10 at predetermined intervals.
  • the opening degree of the liquid outflow side flow rate adjustment valve 204 is adjusted so that the difference between the pressure detected by the liquid outflow pressure detection unit 231 and the pressure detected by the downstream liquid outflow pressure detection unit 232 is constant.
  • the relay bypass flow rate adjustment valve 205 has its opening adjusted based on at least one of the pressure detected by the liquid outflow pressure detection unit 231, the pressure detected by the downstream liquid outflow pressure detection unit 232, and the temperature detected by the relay bypass temperature detection unit 208.
  • the air conditioner 1 has a refrigerant filled inside the piping.
  • the refrigerant may be, for example, natural refrigerants such as carbon dioxide (CO 2 ), hydrocarbons, helium, or other chlorine-free fluorocarbon alternatives such as HFC410A, HFC407C, and HFC404A, or fluorocarbon refrigerants such as R22 and R134a used in existing products.
  • HFC407C is a non-azeotropic refrigerant mixture in which HFCs R32, R125, and R134a are mixed at ratios of 23 wt%, 25 wt%, and 52 wt%, respectively.
  • the piping of the air conditioner 1 may be filled with a heat medium instead of a refrigerant.
  • the heat medium may be, for example, water, brine, or the like.
  • the control unit 10 controls the entire system of the air conditioning apparatus 1, and is configured by, for example, a microprocessor unit equipped with a CPU and a memory.
  • the control unit 10 receives detection information (temperature information and pressure information) from various detection units such as the gas pipe temperature detection units 304a, 304b, the liquid pipe temperature detection units 303a, 303b, the suction temperature detection units 305a, 305b, the liquid outflow pressure detection unit 231, the downstream liquid outflow pressure detection unit 232, the relay bypass temperature detection unit 208, the discharge pressure detection unit 126, the suction pressure detection unit 127, the discharge temperature detection unit 128, and the suction temperature detection unit 129.
  • detection information temperature information and pressure information
  • the control unit 10 also receives instructions from remote controls (not shown) attached to the indoor units 300a, 300b. Based on the detection information received from the various detection parts and instructions from the remote control, the control part 10 controls the driving frequency of the compressor 101, the rotation speed of the heat source side blower 112 and the indoor blower (not shown), the switching of the flow path switching valve 102, the opening and closing of the heating solenoid valves 202a, 202b and the cooling solenoid valves 203a, 203b, the opening and closing of the heat source side flow control valve 109, the bypass flow control valve 110, the load side flow control valves 302a, 302b, the liquid outflow side flow control valve 204 and the relay bypass flow control valve 205, etc.
  • the control unit 10 is composed of a control device 141 provided in the heat source unit 100 and a control device 220 provided in the repeater unit 200, but is not limited to this and may be installed in any or all of the heat source unit 100, indoor units 300a, 300b, and repeater unit 200.
  • the control unit 10 may also be installed separately from the heat source unit 100, indoor units 300a, 300b, and repeater unit 200.
  • the control device 141 and the control device 220 are connected to each other wirelessly or via a wire so that they can communicate with each other and can send and receive various data, etc.
  • the control unit 10 may be composed of a single control device.
  • FIG. 2 is a block diagram showing the functions of the control unit 10 of the air conditioning device 1 according to an embodiment of the present disclosure.
  • the control unit 10 has a storage unit 11, a setting unit 12, and a device control unit 13.
  • the storage means 11 stores various set values, etc.
  • the storage means 11 stores an opening degree table and an air blowing table in which the cooling and heating load capacities of the indoor units 300a and 300b correspond to the opening degree adjustment value of the bypass flow control valve 110, the opening degree adjustment value of the heat source side flow control valve 109, and the output of the heat source side blower 112.
  • the load ratio between the cooling load capacity and the heating load capacity of the indoor units 300a and 300b corresponds to the target temperature of the heat source side heat exchanger 103
  • the target temperature corresponds to the opening degree adjustment value of the bypass flow control valve 110, the opening degree adjustment value of the heat source side flow control valve 109, and the output of the heat source side blower 112.
  • the storage means 11 also stores various calculation formulas such as formulas (1), (2), and (3) described later.
  • the setting means 12 calculates the load ratio between the cooling load capacity and the heating load capacity from various detection values of the load capacity detection unit 20, and switches the operation mode according to the load ratio.
  • the setting means 12 also has a function of judging whether the air conditioner 1 is in cooling-dominant operation or heating-dominant operation.
  • the setting means 12 also collates the cooling/heating load capacities of the multiple indoor units 300a, 300b detected by the load capacity detection unit 20 with the opening degree table and the air blowing table stored in the storage means 11, and sets the opening degree of the bypass flow control valve 110, the opening degree of the heat source side flow control valve 109, and the output of the heat source side blower 112.
  • the setting means 12 calculates a flooding multiplier C corresponding to the dryness of the refrigerant flowing into the heat source side heat exchanger 103 using an arithmetic formula stored in the storage means 11 from the detection values of multiple detection units that detect pressure or temperature, such as the suction pressure detection unit 127, the suction temperature detection unit 129, the discharge pressure detection unit 126, the discharge temperature detection unit 128, the suction temperature detection units 305a, 305b, and the liquid pipe temperature detection units 303a, 303b.
  • the setting means 12 sets the openings of the load side flow control valves 302a, 302b according to the flooding multiplier C obtained by the calculation.
  • the control method for the openings of the load side flow control valves 302a, 302b may be used differently depending on whether the load is low load or not.
  • the setting means 12 calculates a flooding multiplier C corresponding to the dryness of the refrigerant flowing into the heat source side heat exchanger 103, and sets the opening degree of each of the load side flow control valves 302a and 302b according to the flooding multiplier C obtained by the calculation.
  • the equipment control means 13 controls the opening degree of the bypass flow control valve 110, the opening degree of the heat source side flow control valve 109, and the output of the heat source side blower 112 to the opening degree of the bypass flow control valve 110, the opening degree of the heat source side flow control valve 109, and the output of the heat source side blower 112 set by the setting means 12.
  • the equipment control means 13 controls the opening degrees of the load side flow control valves 302a, 302b to the opening degrees of the load side flow control valves 302a, 302b set by the setting means 12.
  • the air conditioner 1 has the following operating modes: full cooling operation, full heating operation, cooling-dominated operation, and heating-dominated operation.
  • Full cooling operation is a mode in which all of the indoor units 300a and 300b perform cooling operation.
  • Full heating operation is a mode in which all of the indoor units 300a and 300b perform heating operation.
  • Cooling-dominated operation is a mode in which the capacity of the cooling operation is greater than the capacity of the heating operation during simultaneous cooling and heating operation.
  • Heating-dominated operation is a mode in which the capacity of the heating operation is greater than the capacity of the cooling operation during simultaneous cooling and heating operation.
  • FIG. 3 is a circuit diagram showing the state of the air conditioning apparatus 1 according to the embodiment of the present disclosure in full cooling operation.
  • FIG. 4 is a circuit diagram showing the state of the air conditioning apparatus 1 according to the embodiment of the present disclosure in full heating operation.
  • FIG. 5 is a circuit diagram showing the state of the air conditioning apparatus 1 according to the embodiment of the present disclosure in cooling-dominated operation.
  • FIG. 6 is a circuit diagram showing the state of the air conditioning apparatus 1 according to the embodiment of the present disclosure in heating-dominated operation.
  • high-pressure refrigerant is indicated by solid arrows
  • low-pressure refrigerant is indicated by dashed arrows.
  • the refrigerant is then separated into gaseous and liquid refrigerant by the gas-liquid separator 201, and the liquid refrigerant flows out from the liquid outlet side, flows through the first heat exchange section 206, the liquid outlet side flow control valve 204, and the second heat exchange section 207, in that order, and branches at the second branch section 250.
  • the branched refrigerant flows into the indoor units 300a and 300b through the first check valves 210a and 210b and the liquid branch pipes 404a and 404b, respectively.
  • the refrigerant that flows into the indoor units 300a and 300b is then depressurized to low pressure by the load side flow rate control valves 302a and 302b, which are controlled by the amount of superheat at the outlet side of the load side heat exchangers 301a and 301b, respectively.
  • the depressurized refrigerant flows into the load side heat exchangers 301a and 301b, where it exchanges heat with the indoor air and evaporates into gas. At that time, the entire room is cooled.
  • the gaseous refrigerant then passes through the gas branch pipes 403a and 403b and the cooling solenoid valves 203a and 203b of the first branch section 240, respectively, before joining and passing through the low pressure pipe 401.
  • the refrigerant that has passed through the second heat exchange section 207 flows into the relay bypass pipe 209. Then, the refrigerant that has flowed into the relay bypass pipe 209 is decompressed to a low pressure by the relay bypass flow rate control valve 205, and then in the second heat exchange section 207, it is heat exchanged with the refrigerant that has passed through the liquid outlet side flow rate control valve 204, i.e., the refrigerant before branching to the relay bypass pipe 209, and evaporates. Furthermore, in the first heat exchange section 206, the refrigerant is heat exchanged with the refrigerant before flowing into the liquid outlet side flow rate control valve 204, and evaporates.
  • the evaporated refrigerant flows into the low pressure pipe 401 and merges with the refrigerant that has passed through the cooling solenoid valves 203a and 203b.
  • the merged refrigerant then passes through the fourth check valve 106, the flow path switching valve 102, and the accumulator 104, and is sucked into the compressor 101.
  • the heating solenoid valves 202a and 202b are closed.
  • the cooling solenoid valves 203a and 203b are open.
  • the refrigerant flows through the third check valve 105 and the fourth check valve 106.
  • the liquid branch pipes 404a and 404b are at lower pressure than the high pressure pipe 402, no refrigerant flows through the second check valves 211a and 211b.
  • the bypass flow rate adjustment valve 110 is closed, no refrigerant flows through the bypass pipe 113.
  • the refrigerant is separated into gaseous refrigerant and liquid refrigerant by the gas-liquid separator 201, and the gaseous refrigerant flows out from the gas outlet side of the gas-liquid separator 201 and branches at the first branch section 240.
  • the branched refrigerant flows into the indoor units 300a and 300b through the heating solenoid valves 202a and 202b and the gas branch pipes 403a and 403b.
  • the refrigerant that flows into the indoor units 300a and 300b is condensed and liquefied by heat exchange with the indoor air in the load side heat exchangers 301a and 301b, respectively. At that time, the entire room is heated.
  • the condensed and liquefied refrigerant then passes through the load side flow rate control valves 302a and 302b, which are controlled by the dryness of the refrigerant on the inlet side of the heat source side heat exchanger 103.
  • the refrigerant that has passed through the load side flow control valves 302a and 302b passes through the liquid branch pipes 404a and 404b and the second check valves 211a and 211b of the second branch section 250, respectively, and then merges.
  • the merged refrigerant passes through the second heat exchange section 207 and flows into the relay bypass piping 209, and is reduced in pressure to a low pressure by the relay bypass flow control valve 205.
  • the refrigerant exchanges heat with the refrigerant that has passed through the liquid outflow side flow control valve 204, i.e., the refrigerant before branching into the relay bypass piping 209, and evaporates.
  • the refrigerant exchanges heat with the refrigerant before flowing into the liquid outflow side flow control valve 204, and evaporates.
  • the evaporated refrigerant flows into the low pressure pipe 401, passes through the sixth check valve 108, and flows into the gas-liquid separation section 111.
  • the refrigerant flowing out of the gas-liquid separation section 111 is depressurized by the heat source side flow rate control valve 109, and is evaporated and gasified in the heat source side heat exchanger 103 by heat exchange with the outdoor air blown by the heat source side blower 112.
  • the gasified refrigerant is sucked into the compressor 101 via the flow path switching valve 102 and the accumulator 104.
  • the heating solenoid valves 202a and 202b are open. Also, the cooling solenoid valves 203a and 203b are closed. Also, since the low pressure pipe 401 is at low pressure and the high pressure pipe 402 is at high pressure, the refrigerant flows through the fifth check valve 107 and the sixth check valve 108. Also, the liquid outflow side flow control valve 204 is closed. Also, since the liquid branch pipes 404a and 404b are at higher pressure than the high pressure pipe 402, the refrigerant does not flow through the first check valves 210a and 210b. Furthermore, since the bypass flow control valve 110 is closed, the refrigerant does not flow through the bypass pipe 113.
  • a cooling request is made from the indoor unit 300a, and a heating request is made from the indoor unit 300b.
  • the high-temperature, high-pressure gas refrigerant discharged from the compressor 101 passes through the flow path switching valve 102 and branches into a refrigerant flowing into the main pipe 114 and a refrigerant flowing into the bypass pipe 113.
  • the refrigerant flowing into the main pipe 114 is heat-exchanged with the outdoor air blown by the heat source side blower 112 in the heat source side heat exchanger 103, and is condensed and liquefied.
  • the condensed and liquefied refrigerant is then depressurized by the heat source side flow rate control valve 109 and reaches the gas-liquid separation section 111.
  • the refrigerant flowing into the bypass pipe 113 is depressurized by the bypass flow rate control valve 110 and reaches the gas-liquid separation section 111.
  • the refrigerant that has flowed into the heat source side heat exchanger 103 and the refrigerant that has flowed into the bypass pipe 113 join together in the gas-liquid separation section 111, and passes through the third check valve 105 and the high pressure pipe 402 to reach the gas-liquid separator 201.
  • the refrigerant is separated by the gas-liquid separator 201 into refrigerant in a gas state and refrigerant in a liquid state.
  • the liquid refrigerant flowing out from the liquid outlet side of the gas-liquid separator 201 passes through the first heat exchange section 206, the liquid outlet flow control valve 204, and the second heat exchange section 207 to reach the second branch section 250.
  • the refrigerant flows into the indoor unit 300a through the first check valve 210a and the liquid branch pipe 404a of the second branch section 250.
  • the refrigerant that flows into the indoor unit 300a is then reduced in pressure to a low level by the load side flow control valve 302a, which is controlled by the amount of superheat on the outlet side of the load side heat exchanger 301a.
  • the reduced pressure refrigerant flows into the load side heat exchanger 301a, where it exchanges heat with the indoor air and evaporates into gas.
  • the room in which the indoor unit 300a is installed is cooled.
  • the gaseous refrigerant then passes through the gas branch pipe 403a and the cooling solenoid valve 203a of the first branch section 240, and flows into the low-pressure pipe 401.
  • the gaseous refrigerant flowing out from the gas outlet side of the gas-liquid separator 201 passes through the heating solenoid valve 202b of the first branch 240, passes through the gas branch pipe 403b, and flows into the indoor unit 300b.
  • the refrigerant that flows into the indoor unit 300b is condensed and liquefied by heat exchange with the indoor air in the load side heat exchanger 301b.
  • the room in which the indoor unit 300b is installed is heated.
  • the condensed and liquefied refrigerant passes through the load side flow control valve 302b controlled by the subcooling amount on the outlet side of the load side heat exchanger 301b, and becomes a liquid state at an intermediate pressure between high pressure and low pressure.
  • the refrigerant in the intermediate pressure liquid state passes through the liquid branch pipe 404b and the second check valve 211b of the second branch 250, and flows into the second heat exchange section 207.
  • the refrigerant then flows into the relay bypass pipe 209, and is reduced in pressure to low pressure by the relay bypass flow rate control valve 205.
  • the refrigerant is heat exchanged with the refrigerant that has passed through the liquid outlet flow rate control valve 204, i.e., the refrigerant before it branches into the relay bypass pipe 209, and evaporates.
  • the refrigerant is heat exchanged with the refrigerant before it flows into the liquid outlet flow rate control valve 204, and evaporates.
  • the evaporated refrigerant flows into the low-pressure pipe 401 and merges with the refrigerant that has passed through the cooling solenoid valve 203a.
  • the merged refrigerant then passes through the fourth check valve 106, the flow path switching valve 102, and the accumulator 104 before being sucked into the compressor 101.
  • the heating solenoid valve 202a is closed and the heating solenoid valve 202b is open.
  • the cooling solenoid valve 203a is open and the cooling solenoid valve 203b is closed.
  • the low-pressure pipe 401 is at low pressure and the high-pressure pipe 402 is at high pressure
  • the refrigerant flows through the third check valve 105 and the fourth check valve 106.
  • the liquid branch pipe 404a is at a lower pressure than the high-pressure pipe 402, the refrigerant does not flow through the second check valve 211a.
  • the liquid branch pipe 404b is at a higher pressure than the high-pressure pipe 402, the refrigerant does not flow through the first check valve 210b.
  • heating-dominant operation Next, heating-dominant operation will be described with reference to Fig. 6.
  • a heating request is made from the indoor unit 300b, and a cooling request is made from the indoor unit 300a.
  • high-temperature, high-pressure gas refrigerant discharged from the compressor 101 passes through the flow path switching valve 102, the fifth check valve 107, and the high-pressure pipe 402, and reaches the gas-liquid separator 201.
  • the refrigerant is separated by the gas-liquid separator 201 into refrigerant in a gas state and refrigerant in a liquid state.
  • the gaseous refrigerant flowing out from the gas outlet side of the gas-liquid separator 201 passes through the heating solenoid valve 202b of the first branch 240, and flows into the indoor unit 300b through the gas branch pipe 403b.
  • the refrigerant that flows into the indoor unit 300b is condensed and liquefied by heat exchange with the indoor air in the load side heat exchanger 301b. At that time, the room in which the indoor unit 300b is installed is heated.
  • the condensed and liquefied refrigerant then passes through the load side flow control valve 302b, which is controlled by the subcooling amount on the outlet side of the load side heat exchanger 301b, and becomes a liquid state at an intermediate pressure between high pressure and low pressure.
  • the refrigerant in an intermediate pressure liquid state passes through the liquid branch pipe 404b and the second check valve 211b of the second branch 250, and flows into the second heat exchange section 207. At this time, the refrigerant flows out from the liquid outflow side of the gas-liquid separator 201 and merges with the liquid refrigerant that has passed through the first heat exchange section 206 and the liquid outflow side flow control valve 204. The merged refrigerant branches into the refrigerant that flows into the second branch section 250 and the refrigerant that flows into the relay bypass piping 209.
  • the refrigerant that flows into the second branch 250 flows through the first check valve 210a of the second branch 250 and the liquid branch pipe 404a into the indoor unit 300a.
  • the refrigerant that flows into the indoor unit 300a is reduced in pressure to a low level by the load side flow control valve 302a, which is controlled by the amount of superheat at the outlet side of the load side heat exchanger 301a.
  • the reduced pressure refrigerant flows into the load side heat exchanger 301a, where it exchanges heat with the indoor air and evaporates into gas. At that time, the room in which the indoor unit 300a is installed is cooled.
  • the gaseous refrigerant then flows through the gas branch pipe 403a and the cooling solenoid valve 203a of the first branch 240 into the low pressure pipe 401.
  • the refrigerant that has flowed into the relay bypass pipe 209 is decompressed to low pressure by the relay bypass flow rate control valve 205, and then in the second heat exchange section 207, it is heat exchanged with the refrigerant that has passed through the liquid outlet flow rate control valve 204, i.e., the refrigerant before branching to the relay bypass pipe 209, and evaporates.
  • the refrigerant is heat exchanged with the refrigerant before flowing into the liquid outlet flow rate control valve 204, and evaporates.
  • the evaporated refrigerant flows into the low-pressure pipe 401 and merges with the refrigerant that has passed through the cooling solenoid valve 203a.
  • the merged refrigerant then passes through the sixth check valve 108 and flows into the gas-liquid separation section 111.
  • the refrigerant is then separated into gas-state refrigerant and liquid-state refrigerant by the gas-liquid separation section 111.
  • the refrigerant flowing out from the liquid outlet side of the gas-liquid separation section 111 to the main pipe 114 is depressurized by the heat source side flow control valve 109, and is heat exchanged with the outdoor air blown by the heat source side blower 112 in the heat source side heat exchanger 103 to evaporate into gas. Meanwhile, the refrigerant flowing out from the gas outlet side of the gas-liquid separation section 111 to the bypass pipe 113 is depressurized by the bypass flow control valve 110, and then merges with the refrigerant flowing out from the main pipe 114. The merged refrigerant passes through the flow path switching valve 102 and the accumulator 104 and is sucked into the compressor 101.
  • the heating solenoid valve 202b is open and the heating solenoid valve 202a is closed.
  • the cooling solenoid valve 203a is open and the cooling solenoid valve 203b is closed. Since the low-pressure pipe 401 is at low pressure and the high-pressure pipe 402 is at high pressure, the refrigerant flows through the fifth check valve 107 and the sixth check valve 108. Furthermore, since the liquid branch pipe 404a is at a lower pressure than the high-pressure pipe 402, the refrigerant does not flow through the second check valve 211a. Furthermore, since the liquid branch pipe 404b is at a higher pressure than the high-pressure pipe 402, the refrigerant does not flow through the first check valve 210b.
  • the opening degree adjustment function of the load side flow rate control valves 302a, 302b using the dryness of the refrigerant Q at the inlet of the heat source side heat exchanger 103 as a control parameter is one of the functions of the control unit 10, and is effective, for example, during the above-mentioned full heating operation (hereinafter, simply referred to as heating).
  • the control method of the opening degree of the load side flow rate control valves 302a, 302b may be used differently depending on whether the load is low load or not.
  • the opening degree adjustment function of the load side flow rate control valves 302a, 302b using the dryness of the refrigerant Q as a control parameter may be effective only during the low load of the full heating operation. Since highly efficient operation is possible at low loads, improvements in the seasonal efficiency of the air conditioning apparatus 1 can be expected.
  • FIG. 7 is a flowchart showing a method for adjusting the opening degree of the load side flow control valve 302 by the control unit 10 of the air conditioning device 1 according to an embodiment of the present disclosure.
  • FIG. 8 is a p-h diagram showing an example of a change in the refrigerant state when the opening degree of the load side flow control valve 302 is adjusted in the air conditioning device 1 according to an embodiment of the present disclosure.
  • the circuit portion between the load side heat exchanger 301 and the heat source side heat exchanger 103 is simplified.
  • the load side flow control valve 302, the liquid outlet side flow control valve 204, and the heat source side flow control valve 109 are provided in this circuit portion, and the refrigerant dryness Q at the inlet of the heat source side heat exchanger 103 is affected by these three flow control valves in a strict sense.
  • the load side flow control valve 302 is provided in this circuit portion.
  • FIG. 4 the control flow of the load side flow control valves 302a and 302b performed by the control unit 10 during heating will be described based on FIGS. 7 to 8. As shown in FIG. 7, first, the temperature and pressure of each part are detected by various detection units (step ST11).
  • the discharge refrigerant flow rate Gr [kg/h] of compressor 101, the specific enthalpy of the discharge section of compressor 101, and the condensing capacity of indoor units 300a, 300b are calculated (step ST12).
  • the discharge refrigerant flow rate Gr of compressor 101 is calculated by multiplying the refrigerant density of the suction section of compressor 101, calculated from the low pressure detected by suction pressure detection unit 127 and the refrigerant temperature detected by suction temperature detection unit 129, by the frequency and displacement volume of compressor 101.
  • the specific enthalpy of the discharge section of compressor 101 can be calculated from the high pressure detected by discharge pressure detection unit 126 and the refrigerant temperature detected by discharge temperature detection unit 128.
  • the condensation capacity of the indoor units 300a, 300b is calculated by multiplying the actual measured value or specification value of the air volume of the indoor units 300a, 300b by the difference between the indoor air temperature detected by the intake temperature detection units 305a, 305b of the indoor units 300a, 300b and the refrigerant temperature detected by the liquid pipe temperature detection units 303a, 303b, which corresponds to the blowing temperature of the indoor units 300a, 300b.
  • corrections may be made taking into account the heat generation amount and bypass factor of the indoor units 300a, 300b.
  • the refrigerant dryness at the inlet of the heat source side heat exchanger 103 is calculated (step ST13).
  • the refrigerant dryness Q at the inlet of the heat source side heat exchanger 103 is calculated from the specific enthalpy of the second refrigerant piping 502a, 502b and the pressure or temperature. If we ignore the slight thermal loss, the specific enthalpy is equal between the second refrigerant piping 502a, 502b where the refrigerant flowing out from the load side heat exchangers 301a, 301b flows during heating and the first refrigerant piping 501 where the refrigerant flowing into the heat source side heat exchanger 103 flows during heating.
  • the specific enthalpy of the first refrigerant piping 501 can be calculated from the difference between the specific enthalpy of the compressor 101 discharge part calculated in step ST12 and the value obtained by dividing the condensation capacity of the indoor units 300a, 300b by the discharge refrigerant flow rate Gr of the compressor 101.
  • the gas saturation density Dg is the refrigerant density at the boundary line between the two-phase state and the gas state (see FIG. 8)
  • the liquid saturation density Dl is the refrigerant density at the boundary line between the liquid state and the two-phase state (see FIG. 8).
  • the gas saturation density Dg and the liquid saturation density Dl can be calculated from the low pressure detected by the suction pressure detection unit 127.
  • the flow rate of the gaseous fluid is faster, mainly due to the difference in density between the liquid and gaseous fluids. Therefore, the greater the proportion of gaseous refrigerant in the two-phase refrigerant flowing into the heat source side heat exchanger 103, i.e., the higher the refrigerant dryness Q at the inlet of the heat source side heat exchanger 103, the faster the flow rate of the refrigerant at the inlet of the heat source side heat exchanger 103 (evaporator during heating). And the faster the flow rate of the refrigerant at the inlet of the heat source side heat exchanger 103, the better the refrigerant distribution performance of the heat source side heat exchanger 103.
  • control unit 10 calculates the current flooding multiplier C according to the following formula (3) using the known variables calculated in steps ST12 to ST14 (step ST15).
  • the current flooding multiplier C is calculated from the gas flow velocity ug and liquid flow velocity ul at the inlet of the heat source side heat exchanger 103, the gas saturation density Dg and liquid saturation density Dl, and the refrigerant dryness Q at the inlet of the heat source side heat exchanger 103.
  • step ST16 determines whether the current flooding multiplier C calculated in step ST15 matches a predetermined target value Ct (e.g., 2.8) (step ST16). If the current flooding multiplier C matches the target value Ct (step ST16; YES), the control ends. If the current flooding multiplier C does not match the target value Ct (step ST16; NO), the control proceeds to step ST17, where the opening of the load side flow rate control valves 302a and 302b is adjusted and controlled, and the control returns to step ST11.
  • a predetermined target value Ct e.g., 2.8
  • step ST16 the current flooding multiplier C does not match the target value Ct if the current flooding multiplier C is greater than the target value Ct or if the current flooding multiplier C is smaller than the target value Ct.
  • the adjustment direction of the opening degree of the load side flow control valves 302a, 302b in step ST17 is as follows.
  • the control unit 10 reduces the opening of the load side flow control valves 302a and 302b to less than the current opening in order to reduce the refrigerant dryness Q at the inlet of the heat source side heat exchanger 103.
  • the refrigerant flow rate becomes slower after the adjustment compared to before the adjustment.
  • the control unit 10 increases the opening of the load side flow control valves 302a and 302b to a value greater than the current opening in order to increase the refrigerant dryness Q at the inlet of the heat source side heat exchanger 103.
  • the refrigerant flow rate becomes faster after the adjustment compared to before the adjustment.
  • the openings of the load side flow control valves 302a, 302b are adjusted so that the refrigerant dryness Q at the inlet of the heat source side heat exchanger 103 becomes the target dryness (hereinafter referred to as the target dryness) and the current flooding multiplier C approaches the target value Ct.
  • the method of controlling the refrigerant dryness Q at the inlet of the heat source side heat exchanger 103 is not limited to the control method using the flooding multiplier C illustrated in FIG. 7.
  • the target dryness should be the refrigerant dryness when the distribution loss reduction rate ⁇ is at its maximum (for example, when the flattening multiplier C is 2.8).
  • the target dryness taking into account the low pressure at the frost limit.
  • the distribution loss of the heat source side heat exchanger 103 which becomes an evaporator during heating, varies depending on, for example, the size or shape of the heat source side heat exchanger 103, so the target value Ct of the flooding multiplier C may also be set according to the size or shape of the evaporator used.
  • the target value Ct of the flooding multiplier C may be, for example, a constant that stabilizes the distribution loss in the evaporator used, or the control unit 10 may calculate and set the target value Ct by calculation so that it is a value that further takes into account the operating state of the air conditioning device 1.
  • the operating state refers to the detection values of various detection units used in the calculation of the flooding multiplier C or the drive frequency of the compressor 101. Note that a table in which the target value Ct is associated with each operating state may be stored in the storage means 11 of the control unit 10.
  • the air conditioning device 1 of the present disclosure calculates the refrigerant dryness Q at the inlet of the heat source side heat exchanger 103 and the flooding multiplier C at this time from the temperatures and pressures of each part detected by the various detection units of the air conditioning device 1. Then, the refrigerant dryness Q at the inlet of the heat source side heat exchanger 103 is controlled by adjusting the opening of the load side flow rate control valves 302a and 302b until the calculated flooding multiplier C reaches the target value Ct.
  • the refrigerant dryness Q and the current flooding multiplier C can be calculated from the detection values of existing detection units used in conventional control, such as the suction pressure detection unit 127, the suction temperature detection unit 129, the discharge pressure detection unit 126, the discharge temperature detection unit 128, the suction temperature detection units 305a, 305b, and the liquid pipe temperature detection units 303a, 303b.
  • existing detection units used in conventional control
  • a separate detection unit may be provided in addition to the existing detection units to calculate a more accurate refrigerant dryness Q and the current flooding multiplier C.
  • each load-side heat exchanger 301 which is a condenser
  • the refrigerant flowing out of each load-side heat exchanger 301 is decompressed by the load-side flow control valve 302 and flows into the heat-source-side heat exchanger 103, which is an evaporator.
  • the control unit 10 adjusts the opening of each load-side flow control valve in a larger direction in order to increase the refrigerant dryness Q at the inlet of the heat-source-side heat exchanger 103.
  • the refrigerant C20 (the refrigerant flowing through the first refrigerant piping 501 shown in FIG.
  • each load side flow control valve 302 When the opening degree of each load side flow control valve 302 is adjusted to increase the refrigerant dryness Q at the inlet of the heat source side heat exchanger 103 as described above, the refrigerant C10 flowing out of each load side heat exchanger 301 (the refrigerant flowing through the second refrigerant pipes 502a, 502b shown in Figure 4) also becomes a refrigerant state with a higher refrigerant dryness Q than the refrigerant C1 flowing out of each load side heat exchanger 301 before the adjustment.
  • the opening of the load side flow control valve 302 is adjusted using the refrigerant dryness Q of the two-phase refrigerant (refrigerant C20) at the inlet of the heat source side heat exchanger 103 as a control parameter.
  • the refrigerant dryness Q at the inlet of the heat source side heat exchanger 103 is prevented from decreasing too much compared to conventional methods, thereby suppressing the decrease in flow rate and reducing the decrease in refrigerant distribution performance in the heat source side heat exchanger 103. This also makes it possible to suppress the decrease in evaporation capacity due to distribution loss in the heat source side heat exchanger 103.
  • the refrigerant is a liquid refrigerant with a degree of subcooling at the outlet of the load side heat exchanger 301, but in this disclosure, the dryness of the refrigerant (refrigerant dryness Q) at the inlet of the heat source side heat exchanger 103 is controlled, so the refrigerant C10 may be a two-phase refrigerant at the outlet of the load side heat exchanger 301.
  • the air conditioning device 1 includes a heat source unit 100 having a compressor 101 that compresses and discharges the refrigerant, a load side heat exchanger 301 that functions as a condenser during heating operation, a flow rate control valve (load side flow rate control valve 302) that adjusts the flow rate of the refrigerant flowing out of the load side heat exchanger 301 during heating operation, and a heat source side heat exchanger 103 that functions as an evaporator during heating operation.
  • the air conditioning device 1 also includes a control unit 10 that controls the opening degree of the load side flow rate control valve 302. During heating operation, the control unit 10 adjusts the opening degree of the load side flow rate control valve 302 using the dryness of the refrigerant flowing into the heat source side heat exchanger 103 (refrigerant dryness Q) as a control parameter.
  • the opening of the load side flow control valve 302 is adjusted using the dryness of the refrigerant (refrigerant dryness Q) flowing into the heat source side heat exchanger 103, which is an evaporator, as a control parameter.
  • the dryness of the refrigerant (refrigerant dryness Q) flowing into the heat source side heat exchanger 103 is an evaporator.
  • the decrease in the dryness of the refrigerant (refrigerant dryness Q) flowing into the heat source side heat exchanger 103 is reduced, thereby reducing the decrease in the refrigerant flow rate. Therefore, it is possible to provide an air conditioning device 1 with improved refrigerant distribution performance of the heat source side heat exchanger 103 during low load heating operation.
  • the control method can improve the refrigerant distribution performance under low load conditions, so manufacturing issues can be eliminated compared to changing the structure of the heat source side heat exchanger 103 itself.
  • the air conditioning device 1 also includes a discharge temperature detection unit 128 and a discharge pressure detection unit 126 which detect the temperature and pressure of the refrigerant discharged from the compressor 101, and a suction temperature detection unit 129 and a suction pressure detection unit 127 which detect the temperature and pressure of the refrigerant sucked into the compressor 101.
  • the air conditioning device 1 also includes a suction temperature detection unit 305 which detects the temperature of air before heat exchange with the refrigerant in the load side heat exchanger 301, and a liquid pipe temperature detection unit 303 which detects the temperature of the refrigerant after it flows out of the load side heat exchanger 301 and before it flows into the load side flow control valve 302 during heating operation.
  • the control unit 10 then adjusts the opening of the load side flow control valve 302 according to a calculated value (e.g., flooding multiplier C) calculated from the detection values of the discharge temperature detection unit 128, the discharge pressure detection unit 126, the suction temperature detection unit 129, the suction pressure detection unit 127, the suction temperature detection unit 305, and the liquid pipe temperature detection unit 303 according to an arithmetic expression that includes the dryness fraction (refrigerant dryness fraction Q) as a variable.
  • a calculated value e.g., flooding multiplier C
  • the detection unit provided in a typical air conditioning device 1 can be used, and there is no need to add additional detection, thereby reducing costs.
  • control unit 10 calculates a flooding multiplier C of the liquid flow velocity ul and gas flow velocity ug of the refrigerant flowing into the heat source side heat exchanger 103, and adjusts the opening of the load side flow control valve 302 so that the calculated flooding multiplier C becomes a target value Ct that corresponds to a predetermined target dryness.
  • the target value Ct of the flooding multiplier C is a constant. This simplifies the calculation for adjusting the opening of the load-side flow control valve 302, and reduces the control load.
  • the control unit 10 reduces the opening degree of the load side flow control valve 302 from the current opening degree.Furthermore, when the calculated flooding multiplier C is less than the target value Ct, the control unit 10 increases the opening degree of the load side flow control valve 302 from the current opening degree.
  • the opening of the load side flow control valve 302 is controlled so that the calculated flooding multiplier C approaches the target value Ct, and the flow rate can be optimized by adjusting the dryness of the refrigerant flowing into the heat source side heat exchanger 103, thereby improving the refrigerant distribution performance.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Air Conditioning Control Device (AREA)

Abstract

Un dispositif de climatisation comprend : un compresseur qui comprime et évacue un fluide frigorigène ; un échangeur de chaleur côté charge qui fonctionne comme un condenseur pendant une opération de chauffage ; une soupape de réglage de débit qui règle le débit du fluide frigorigène s'écoulant hors de l'échangeur de chaleur côté charge pendant l'opération de chauffage ; un échangeur de chaleur côté source de chaleur qui fonctionne en tant qu'évaporateur pendant l'opération de chauffage ; et une unité de commande qui commande le degré d'ouverture de la soupape de réglage de débit, l'unité de commande réglant pendant l'opération de chauffage, en tant que paramètre de commande, le degré d'ouverture de la soupape de réglage de débit à l'aide du degré de siccité du fluide frigorigène s'écoulant dans l'échangeur de chaleur côté source de chaleur.
PCT/JP2023/004284 2023-02-09 2023-02-09 Dispositif de climatisation WO2024166276A1 (fr)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015094520A (ja) * 2013-11-12 2015-05-18 三菱電機株式会社 冷凍サイクル装置
WO2017138059A1 (fr) * 2016-02-08 2017-08-17 三菱電機株式会社 Dispositif de climatisation
JP2018077037A (ja) * 2016-10-25 2018-05-17 三星電子株式会社Ｓａｍｓｕｎｇ Ｅｌｅｃｔｒｏｎｉｃｓ Ｃｏ．，Ｌｔｄ． 空気調和装置
WO2018173256A1 (fr) * 2017-03-24 2018-09-27 三菱電機株式会社 Dispositif de climatisation
WO2020161761A1 (fr) * 2019-02-04 2020-08-13 三菱電機株式会社 Échangeur de chaleur et conditionneur d'air équipé de celui-ci

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015094520A (ja) * 2013-11-12 2015-05-18 三菱電機株式会社 冷凍サイクル装置
WO2017138059A1 (fr) * 2016-02-08 2017-08-17 三菱電機株式会社 Dispositif de climatisation
JP2018077037A (ja) * 2016-10-25 2018-05-17 三星電子株式会社Ｓａｍｓｕｎｇ Ｅｌｅｃｔｒｏｎｉｃｓ Ｃｏ．，Ｌｔｄ． 空気調和装置
WO2018173256A1 (fr) * 2017-03-24 2018-09-27 三菱電機株式会社 Dispositif de climatisation
WO2020161761A1 (fr) * 2019-02-04 2020-08-13 三菱電機株式会社 Échangeur de chaleur et conditionneur d'air équipé de celui-ci

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