EP4030116B1 - Outdoor unit and refrigeration cycle device - Google Patents

Outdoor unit and refrigeration cycle device Download PDF

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Publication number
EP4030116B1
EP4030116B1 EP19944704.6A EP19944704A EP4030116B1 EP 4030116 B1 EP4030116 B1 EP 4030116B1 EP 19944704 A EP19944704 A EP 19944704A EP 4030116 B1 EP4030116 B1 EP 4030116B1
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EP
European Patent Office
Prior art keywords
refrigerant
compressor
flow rate
control valve
controller
Prior art date
Legal status (The legal status 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 status listed.)
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Application number
EP19944704.6A
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German (de)
English (en)
French (fr)
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EP4030116A4 (en
EP4030116A1 (en
Inventor
Tomotaka Ishikawa
Yusuke Arii
Motoshi HAYASAKA
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Mitsubishi Electric Corp
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Mitsubishi Electric Corp
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Publication of EP4030116A4 publication Critical patent/EP4030116A4/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B40/00—Subcoolers, desuperheaters or superheaters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/13—Economisers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/19—Pumping down refrigerant from one part of the cycle to another part of the cycle, e.g. when the cycle is changed from cooling to heating, or before a defrost cycle is started
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/23—Separators
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/19—Pressures
    • F25B2700/193—Pressures of the compressor
    • F25B2700/1931—Discharge pressures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/19—Pressures
    • F25B2700/193—Pressures of the compressor
    • F25B2700/1933—Suction pressures

Definitions

  • the present disclosure relates to an outdoor unit and a refrigeration cycle apparatus.
  • Japanese Patent Laying-Open No. 2014-01917 discloses a refrigeration apparatus having an intermediate injection flow path and a suction injection flow path.
  • a portion of refrigerant flowing from a condenser toward an evaporator can be merged with the intermediate pressure refrigerant in a compressor using the intermediate injection flow path, and can also be merged with the low pressure refrigerant to be suctioned into the compressor in a suction flow path using the suction injection flow path. Accordingly, in a case where using the intermediate injection flow path leads to deterioration of operation efficiency, the suction injection flow path can be used to decrease the discharge temperature of the compressor.
  • a pump down operation is an operation to transfer refrigerant from a load device to an outdoor unit and store the refrigerant therein, by placing an on-off valve or the like on a pipe through which liquid refrigerant flows in a main refrigerant circuit, and operating a compressor with the pipe being blocked.
  • US 2015/338121 describes an air-conditioning apparatus that includes: a first bypass pipe connected to an inlet-side passage of an accumulator through a second expansion device, a second passage of a subcooling heat exchanger for exchanging heat between refrigerant flowing through the second passage of the subcooling heat exchanger and refrigerant flowing through a first passage of the subcooling heat exchanger, and a first opening and closing device; a second bypass pipe branched from the first bypass pipe between the subcooling heat exchanger and the first opening and closing device and connected to an injection port of a compressor through a second opening and closing device; and a third bypass pipe branched from a refrigerant pipe between a heat source-side heat exchanger and a use-side heat exchanger and connected to a refrigerant pipe between an inlet side of the compressor and an outlet side of the accumulator through a third expansion device.
  • WO 2008/130357 describes a refrigerant vapor compression system includes a flash tank economizer defining a separation chamber is disposed in the refrigerant circuit intermediate a refrigerant heat rejection heat exchanger and a refrigerant heat absorption heat exchanger.
  • JP 2009-156531 A discloses an outdoor unit according to the preamble of claim 1.
  • An object of the present invention is to provide an outdoor unit and a refrigeration cycle apparatus with reduced refrigerant recovery time during a pump down operation.
  • the present disclosure relates to an outdoor unit of a refrigeration cycle apparatus, the outdoor unit being connectable to a load device including a first expansion device and an evaporator.
  • the outdoor unit includes: a first flow path configured to form a circulation flow path through which refrigerant circulates, by being connected to the load device; a compressor and a condenser disposed on the first flow path; a second flow path configured to branch from a branch point on the first flow path downstream of the condenser in a direction in which the refrigerant circulates, and to return, to the compressor, the refrigerant that has passed through the condenser; a second expansion device, a receiver, and a flow rate control valve disposed on the second flow path in order from the branch point; and a heat exchanger having a first passage and a second passage and configured to exchange heat between the refrigerant flowing in the first passage and the refrigerant flowing in the second passage.
  • the first passage of the heat exchanger is disposed between the condenser and the branch point on the first flow passage.
  • the second passage of the heat exchanger is disposed between the flow rate control valve and the compressor on the second flow passage.
  • the flow rate control valve is configured to adjust an exhaust flow rate of liquid refrigerant from the receiver.
  • the outdoor unit of the present invention even when refrigerant recovery progresses and a condensation temperature becomes close to an outside air temperature during a pump down operation, the refrigerant is condensed with the efficiency of the heat exchanger being maintained. This can reduce time required for the refrigerant recovery.
  • Fig. 1 is an overall configuration diagram of a refrigeration cycle apparatus according to the present embodiment. It should be noted that Fig. 1 functionally shows the connection relation and the arrangement configuration of devices in the refrigeration cycle apparatus, and does not necessarily show an arrangement in a physical space.
  • a refrigeration cycle apparatus 1 includes an outdoor unit 2, a load device 3, and pipes 84 and 88.
  • Outdoor unit 2 has a refrigerant outlet port PO2 and a refrigerant inlet port PI2 for connecting to load device 3.
  • Load device 3 has a refrigerant outlet port PO3 and a refrigerant inlet port PI3 for connecting to outdoor unit 2.
  • Pipe 84 connects refrigerant outlet port PO2 of outdoor unit 2 to refrigerant inlet port PI3 of load device 3.
  • Pipe 88 connects refrigerant outlet port PO3 of load device 3 to refrigerant inlet port PI2 of outdoor unit 2.
  • Outdoor unit 2 of refrigeration cycle apparatus 1 is connectable to load device 3.
  • Outdoor unit 2 includes a compressor 10 having a suction port G1, a discharge port G2, and an intermediate pressure port G3, a condenser 20, a fan 22, a heat exchanger 30, and pipes 80 to 82 and 89.
  • Heat exchanger 30 has a first passage H1 and a second passage H2, and is configured to exchange heat between refrigerant flowing in first passage H1 and the refrigerant flowing in second passage H2.
  • Load device 3 includes a first expansion valve 50, an evaporator 60, pipes 85, 86, and 87, and an on-off valve 28.
  • Evaporator 60 is configured to perform heat exchange between air and the refrigerant. In refrigeration cycle apparatus 1, evaporator 60 evaporates the refrigerant by absorbing heat from the air in a space to be cooled.
  • First expansion valve 50 is, for example, a temperature expansion valve controlled independently of outdoor unit 2. It should be noted that first expansion valve 50 may be an electronic expansion valve which can decompress the refrigerant.
  • On-off valve 28 is closed when load device 3 stops operation, to block the refrigerant.
  • Compressor 10 compresses the refrigerant suctioned from pipe 89, and discharges the compressed refrigerant to pipe 80.
  • Compressor 10 can arbitrarily change a drive frequency by inverter control.
  • compressor 10 is provided with intermediate pressure port G3, and allows the refrigerant from intermediate pressure port G3 to flow into an intermediate portion of a compression process.
  • Compressor 10 is configured to adjust a rotation speed according to a control signal from a controller 100. By adjusting the rotation speed of compressor 10, a circulation amount of the refrigerant is adjusted, and the capability of refrigeration cycle apparatus 1 can be adjusted.
  • various types of compressors can be adopted, and for example, a compressor of scroll type, rotary type, screw type, or the like can be adopted.
  • Condenser 20 is configured such that the high-temperature, high-pressure gas refrigerant discharged from compressor 10 performs heat exchange with outside air (heat dissipation). By this heat exchange, the refrigerant is condensed and transforms into a liquid phase.
  • the refrigerant discharged from compressor 10 to pipe 80 is condensed and liquefied in condenser 20, and flows into pipe 81.
  • Fan 22 for blowing the outside air is attached to condenser 20 in order to increase the efficiency of heat exchange.
  • Fan 22 supplies condenser 20 with the outside air with which the refrigerant performs heat exchange in condenser 20. By adjusting the number of revolutions of fan 22, a refrigerant pressure on a discharge side of compressor 10 (a high pressure-side pressure) can be adjusted.
  • the refrigerant used for a refrigerant circuit of refrigeration cycle apparatus 1 is CO 2 .
  • another refrigerant may be used.
  • condenser 20 a device which cools the refrigerant such as CO 2 in a supercritical state
  • condenser 20 an amount of decrease from a reference temperature of the refrigerant in the supercritical state
  • subcool an amount of decrease from a reference temperature of the refrigerant in the supercritical state
  • a first flow path F1 from refrigerant inlet port PI2 to refrigerant outlet port PO2 via compressor 10, condenser 20, and first passage H1 of heat exchanger 30 forms, together with a flow path on which first expansion valve 50 and evaporator 60 of load device 3 are disposed, a circulation flow path through which the refrigerant circulates.
  • this circulation flow path will also be referred to as a "main refrigerant circuit" of a refrigeration cycle.
  • Outdoor unit 2 further includes pipes 91, 92, and 94 configured to cause the refrigerant to flow from a portion of the circulation flow path between an outlet of first passage H1 and refrigerant outlet port PO2 to an inlet of second passage H2, and pipe 96 configured to cause the refrigerant to flow from an outlet of second passage H2 to intermediate pressure port G3 of compressor 10.
  • a second flow path F2 that branches from the main refrigerant circuit and delivers the refrigerant to compressor 10 via second passage H2 will also be referred to as an "injection flow path".
  • Outdoor unit 2 further includes a receiver 73 disposed on second flow path F2 and configured to store the refrigerant.
  • a second expansion valve 71 is disposed between pipes 91 and 92, pipe 91 branching from the portion of the circulation flow path between the outlet of first passage H1 and refrigerant outlet port PO2, and pipe 92 connected to an inlet of receiver 73.
  • Outdoor unit 2 further includes a degassing pipe 93 that connects a gas exhaust outlet of receiver 73 to second passage H2 and is configured to exhaust a refrigerant gas within receiver 73, a throttle device 70 disposed between degassing pipe 93 and pipe 94 leading to second passage H2, and a flow rate control valve 72 configured to adjust a flow rate of the refrigerant in pipe 94 connected to a liquid refrigerant exhaust outlet of receiver 73.
  • Pipe 91 is a pipe that branches from the main refrigerant circuit and causes the refrigerant to flow into receiver 73.
  • Second expansion valve 71 is an electronic expansion valve which can decrease the pressure of the refrigerant at a high pressure portion of the main refrigerant circuit to an intermediate pressure.
  • Receiver 73 is a container in which the refrigerant decompressed and having two phases is separated into a gas phase and a liquid phase, and which can store the refrigerant and adjust the circulation amount of the refrigerant in the main refrigerant circuit.
  • Degassing pipe 93 connected to an upper portion of receiver 73 and pipe 94 connected to a lower portion of receiver 73 are pipes for taking out the refrigerant separated into gas refrigerant and liquid refrigerant within receiver 73, in a separated state.
  • Flow rate control valve 72 adjusts the amount of the liquid refrigerant to be exhausted from pipe 94, and thereby can adjust the amount of the refrigerant in receiver 73.
  • receiver 73 By providing receiver 73 on the injection flow path as described above, it becomes easy to ensure a subcool in pipes 82 and 83 which are liquid pipes. This is because, since receiver 73 generally includes the gas refrigerant therein and a refrigerant temperature reaches a saturation temperature, it is not possible to ensure a subcool if receiver 73 is disposed on pipe 82.
  • receiver 73 is provided at an intermediate pressure portion, it becomes possible to store the intermediate pressure liquid refrigerant within receiver 73 even when the pressure at the high pressure portion of the main refrigerant circuit is high and the refrigerant is in the supercritical state.
  • the design pressure of the container of receiver 73 can be set to be lower than that of the high pressure portion, and cost reduction by thinning the container can also be achieved.
  • Outdoor unit 2 further includes pressure sensors 110 and 111, temperature sensors 120 to 123, and controller 100 configured to control compressor 10, second expansion valve 71, and flow rate control valve 72.
  • Pressure sensor 110 detects a pressure PL at the suction port portion of compressor 10, and outputs a detection value thereof to controller 100.
  • Pressure sensor 111 detects a discharge pressure PH of compressor 10, and outputs a detection value thereof to controller 100.
  • Temperature sensor 120 detects a discharge temperature TH of compressor 10, and outputs a detection value thereof to controller 100.
  • Temperature sensor 121 detects a refrigerant temperature T1 in pipe 81 at an outlet of condenser 20, and outputs a detection value thereof to controller 100.
  • Temperature sensor 122 detects a refrigerant temperature T2 at the outlet of first passage H1 on a cooled side of heat exchanger 30, and outputs a detection value thereof to controller 100.
  • Temperature sensor 123 detects an outside air temperature TA, which is an ambient temperature of outdoor unit 2, and outputs a detection value thereof to controller 100.
  • second flow path F2 controls discharge temperature TH of compressor 10 by causing the refrigerant decompressed and having two phases to flow into compressor 10.
  • the amount of the refrigerant in the main refrigerant circuit can be adjusted by receiver 73 placed on second flow path F2.
  • second flow path F2 also ensures supercooling of the refrigerant in the main refrigerant circuit by heat exchange by heat exchanger 30.
  • Controller 100 includes a CPU (Central Processing Unit) 102, a memory 104 (a ROM (Read Only Memory) and a RAM (Random Access Memory)), input/output buffers (not shown) for inputting/outputting various signals, and the like.
  • CPU 102 expands programs stored in the ROM onto the RAM or the like and executes the programs.
  • the programs stored in the ROM are programs describing processing procedures of controller 100. According to these programs, controller 100 performs control of the devices in outdoor unit 2. This control can be processed not only by software but also by dedicated hardware (electronic circuitry).
  • Controller 100 feedback-controls second expansion valve 71 such that discharge temperature TH of compressor 10 matches a target temperature.
  • Fig. 2 is a flowchart for illustrating control of second expansion valve 71.
  • controller 100 increases a degree of opening of second expansion valve 71 (S22).
  • the refrigerant flowing into intermediate pressure port G3 via receiver 73 increases, and thus discharge temperature TH decreases.
  • controller 100 decreases the degree of opening of second expansion valve 71 (S24). Thereby, the refrigerant flowing into intermediate pressure port G3 via receiver 73 decreases, and thus discharge temperature TH increases.
  • controller 100 When discharge temperature TH is equal to the target temperature (NO in S21 and NO in S23), controller 100 maintains the degree of opening of second expansion valve 71 in the present state.
  • controller 100 controls the degree of opening of second expansion valve 71 such that discharge temperature TH of compressor 10 approaches the target temperature.
  • controller 100 feedback-controls flow rate control valve 72 such that refrigerant temperature T1 at the outlet of condenser 20 matches a target temperature, in order to ensure a subcool SC of the refrigerant at the outlet of condenser 20.
  • Fig. 3 is a flowchart for illustrating control of flow rate control valve 72.
  • controller 100 increases the degree of opening of flow rate control valve 72 (S34).
  • the amount of the liquid refrigerant to be exhausted from receiver 73 increases and the amount of the liquid refrigerant stored in receiver 73 decreases, and thus the amount of the refrigerant circulating through the main refrigerant circuit increases. Accordingly, refrigerant temperature T1 decreases, and thus subcool SC increases.
  • controller 100 When subcool SC is equal to the target value (NO in S31 and NO in S33), controller 100 maintains the degree of opening of flow rate control valve 72 in the present state.
  • controller 100 controls the degree of opening of flow rate control valve 72 such that refrigerant temperature T1 at the outlet of condenser 20 approaches the target temperature.
  • controller 100 feedback-controls flow rate control valve 72 such that refrigerant temperature T1 at the outlet of condenser 20 matches the target temperature, in order to ensure subcool SC of the refrigerant at the outlet of condenser 20, and in a pump down operation, controller 100 closes flow rate control valve 72 to recover the liquid refrigerant to receiver 73.
  • the pump down operation is an operation to transfer the refrigerant from load device 3 to outdoor unit 2 and store the refrigerant therein, by placing on-off valve 28 or the like on pipe 85 through which the liquid refrigerant flows in the main refrigerant circuit, and operating compressor 10 with pipe 85 being blocked.
  • the pump down operation is performed, for example, by closing first expansion valve 50 or on-off valve 28 before stopping operation, and thereafter operating compressor 10.
  • a signal for instructing to start the pump down operation is not transmitted particularly from load device 3 to outdoor unit 2, and the pump down operation is performed in outdoor unit 2 by continuing the normal operation when pressure PL at the low pressure portion detected by pressure sensor 110 decreases to a threshold value PA.
  • controller 100 In the pump down operation, when on-off valve 28 is closed and pressure PL at the low pressure portion detected by pressure sensor 110 decreases to a threshold value PB, controller 100 is configured to stop compressor 10 and stop a pump down. Since compressor 10 is configured such that the refrigerant may not pass therethrough when it is stopped, the refrigerant does not flow back to load device 3.
  • Fig. 4 is a flowchart for illustrating control during the pump down operation.
  • controller 100 determines whether or not pressure PL at the low pressure portion detected by pressure sensor 110 is lower than threshold value PA.
  • threshold value PA When PL ⁇ threshold value PA is satisfied (YES in S41), the pump down operation in and after step S42 is performed.
  • PL ⁇ threshold value PA is not satisfied (NO in S41), the pump down operation is not performed, and the control is returned to the processing in the normal operation in step S47.
  • step S42 controller 100 determines whether or not refrigerant temperature T1 in condenser 20 is lower than TA+ ⁇ .
  • ⁇ indicates a temperature difference between the refrigerant and the outside air that may cause a significant reduction in the efficiency of condensing the refrigerant in condenser 20 if the temperature difference becomes further smaller, and is a value determined as appropriate.
  • step S43 controller 100 closes flow rate control valve 72. Thereby, the gas refrigerant is exhausted from receiver 73 through degassing pipe 93, and the liquid refrigerant is recovered to receiver 73.
  • step S44 controller 100 slightly increases the degree of opening of flow rate control valve 72. Thereby, the liquid refrigerant stored in receiver 73 flows to second passage H2 of heat exchanger 30.
  • flow rate control valve 72 is closed, the gas refrigerant flows to second passage H2 of heat exchanger 30 through degassing pipe 93. In the state where the gas refrigerant flows, the coefficient of heat transfer between the heat exchanger and the refrigerant in second passage H2 is low.
  • the coefficient of heat transfer between the heat exchanger and the refrigerant in second passage H2 is improved by 10 times or more.
  • the refrigerant which has become less condensed in condenser 20 at a stage in which the recovery of the liquid refrigerant has progressed to some extent is condensed in heat exchanger 30, and thus the recovery of the liquid refrigerant can progress.
  • the degree of opening of flow rate control valve 72 in step S44 is set to fall within a range in which the amount of the recovered liquid refrigerant in receiver 73 increases.
  • controller 100 increases the rotation speed of compressor 10, although controller 100 does not necessarily have to perform this step. This can reduce time for recovering the remaining refrigerant which has become less condensed due to the progress of recovery.
  • step S46 controller 100 determines whether or not pressure PL at the low pressure portion detected by pressure sensor 110 decreases to threshold value PB.
  • Threshold value PB is a value lower than threshold value PA, and is a determination value for determining that the recovery of the refrigerant in load device 3 is completed. As long as pressure PL does not decrease to threshold value PB (NO in S46), controller 100 continues the operation of compressor 10 and continues the pump down operation.
  • step S47 controller 100 stops compressor 10 and terminates the pump down.
  • controller 100 closes flow rate control valve 72 to store the liquid refrigerant in receiver 73. Then, at a second time point when the amount of the liquid refrigerant in receiver 73 increases and the efficiency of condenser 20 decreases, controller 100 slightly opens flow rate control valve 72 to improve the efficiency of heat exchanger 30 and promote condensation of the refrigerant in first passage H1. This can reduce time taken to complete the pump down operation.
  • the present disclosure relates to outdoor unit 2 of refrigeration cycle apparatus 1, outdoor unit 2 being connectable to load device 3 including first expansion valve 50 corresponding to the "first expansion device” and evaporator 60.
  • Outdoor unit 2 includes: first flow path F1 configured to form a circulation flow path through which refrigerant circulates, by being connected to load device 3; compressor 10 and condenser 20 disposed on first flow path F1; second flow path F2 configured to branch from a branch point on first flow path F1 downstream of condenser 20 in a direction in which the refrigerant circulates, and to return, to compressor 10, the refrigerant that has passed through condenser 20; second expansion valve 71 corresponding to the "second expansion device", receiver 73, and flow rate control valve 72 disposed on second flow path F2 in order from the branch point; heat exchanger 30 having first passage H1 and second passage H2 and configured to exchange heat between the refrigerant flowing in first passage H1 and the refrigerant flowing in second passage H2; and controller 100.
  • first flow path F1 configured to form a circulation flow path through which refrigerant circulates, by being connected to load device 3
  • compressor 10 and condenser 20 disposed on first flow path F1
  • First passage H1 of heat exchanger 30 is disposed between condenser 20 and the branch point on first flow path F1.
  • Second passage H2 of heat exchanger 30 is disposed between flow rate control valve 72 and compressor 10 on second flow path F2.
  • Flow rate control valve 72 is configured to adjust an exhaust flow rate of liquid refrigerant from receiver 73.
  • Controller 100 is configured to control compressor 10 and flow rate control valve 72.
  • controller 100 When a pump down operation for recovering the refrigerant to receiver 73 is started, controller 100 is configured to control a control state of compressor 10 and flow rate control valve 72, at a first time point, to a first state in which flow rate control valve 72 is closed while compressor 10 is operated.
  • controller 100 is configured to transition, at a second time point after the first time point, the control state from the first state to a second state in which flow rate control valve 72 is opened while compressor 10 is operated.
  • the amount of the liquid refrigerant in receiver 73 at the second time point is larger than the amount of the liquid refrigerant in receiver 73 at the first time point.
  • controller 100 controls the control state of compressor 10 and flow rate control valve 72 to the second state.
  • controller 100 controls the control state of compressor 10 and flow rate control valve 72 to the second state.
  • controller 100 is configured to set the rotation speed of compressor 10 in the second state to be higher than the rotation speed of compressor 10 in the first state. This can reduce time for recovering the remaining refrigerant which has become less condensed due to the progress of recovery.
  • refrigeration cycle apparatus 1 may be utilized in an air conditioner or the like.
  • 1 refrigeration cycle apparatus; 2: outdoor unit; 3: load device; 10: compressor; 20: condenser; 22: fan; 28: on-off valve; 30: heat exchanger; 71: second expansion valve; 50: first expansion valve; 60: evaporator; 70: throttle device; 72: flow rate control valve; 73: receiver; 80, 81, 82, 83, 84, 85, 88, 89, 91, 92, 94, 96: pipe; 93: degassing pipe; 100: controller; 104: memory; 110, 111: pressure sensor; 120, 121, 122, 123: temperature sensor; F1: first flow path; F2: second flow path; G1: suction port; G2: discharge port; G3: intermediate pressure port; H1: first passage; H2: second passage.

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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)
  • Compression-Type Refrigeration Machines With Reversible Cycles (AREA)
EP19944704.6A 2019-09-09 2019-09-09 Outdoor unit and refrigeration cycle device Active EP4030116B1 (en)

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Application Number Priority Date Filing Date Title
PCT/JP2019/035373 WO2021048901A1 (ja) 2019-09-09 2019-09-09 室外ユニットおよび冷凍サイクル装置

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EP4030116A1 EP4030116A1 (en) 2022-07-20
EP4030116A4 EP4030116A4 (en) 2022-09-07
EP4030116B1 true EP4030116B1 (en) 2023-10-11

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EP (1) EP4030116B1 (ja)
JP (1) JP7224480B2 (ja)
CN (1) CN114341567B (ja)
DK (1) DK4030116T3 (ja)
ES (1) ES2964488T3 (ja)
FI (1) FI4030116T3 (ja)
WO (1) WO2021048901A1 (ja)

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CN113294925A (zh) * 2021-05-21 2021-08-24 浙江国祥股份有限公司 一种带复合式经济器的蒸发冷凝式冷水机组
WO2023199511A1 (ja) * 2022-04-15 2023-10-19 三菱電機株式会社 冷凍サイクル装置
WO2024023993A1 (ja) * 2022-07-27 2024-02-01 三菱電機株式会社 冷凍サイクル装置

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EP4030116A4 (en) 2022-09-07
CN114341567A (zh) 2022-04-12
CN114341567B (zh) 2024-01-02
WO2021048901A1 (ja) 2021-03-18
DK4030116T3 (da) 2023-11-13
EP4030116A1 (en) 2022-07-20
JP7224480B2 (ja) 2023-02-17
FI4030116T3 (fi) 2023-11-02
JPWO2021048901A1 (ja) 2021-03-18
ES2964488T3 (es) 2024-04-08

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