WO2022162776A1 - 冷凍システム - Google Patents

冷凍システム Download PDF

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Publication number
WO2022162776A1
WO2022162776A1 PCT/JP2021/002785 JP2021002785W WO2022162776A1 WO 2022162776 A1 WO2022162776 A1 WO 2022162776A1 JP 2021002785 W JP2021002785 W JP 2021002785W WO 2022162776 A1 WO2022162776 A1 WO 2022162776A1
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WO
WIPO (PCT)
Prior art keywords
defrosting
heat exchanger
blower
indoor heat
refrigeration system
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.)
Ceased
Application number
PCT/JP2021/002785
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English (en)
French (fr)
Japanese (ja)
Inventor
歩 江上
達也 ▲雑▼賀
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Mitsubishi Electric Corp
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Mitsubishi Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Priority to JP2022577869A priority Critical patent/JP7412608B2/ja
Priority to PCT/JP2021/002785 priority patent/WO2022162776A1/ja
Publication of WO2022162776A1 publication Critical patent/WO2022162776A1/ja
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • F25B47/00—Arrangements for preventing or removing deposits or corrosion, not provided for in another subclass
    • F25B47/02—Defrosting cycles

Definitions

  • the present disclosure relates to refrigeration systems.
  • refrigerators capable of starting defrosting operation at an appropriate timing have been known (see Patent Document 1, for example).
  • This refrigerator measures heat exchange between the refrigerant and air based on the measurement results of the temperature of the refrigerant flowing through a heat exchanger that constitutes a part of the refrigeration cycle and the intake temperature and blowout temperature of the air that passes through the heat exchanger.
  • a temperature efficiency which expresses the efficiency, is calculated.
  • This refrigerator combines the amount of frost on the heat exchanger predicted based on the calculated change trend of the temperature efficiency from the start of the cooling operation, and the temperature efficiency threshold preset according to the model of the refrigerator.
  • Optimal defrosting start timing is determined from. This refrigerator starts the defrosting operation when the temperature efficiency reaches or exceeds the threshold.
  • An object of the present disclosure is to provide a refrigeration system that can appropriately set the timing of defrosting operation by a method other than temperature efficiency.
  • the refrigeration system of the present disclosure includes a compressor, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger that are annularly connected, a defrosting section that removes frost adhering to the indoor heat exchanger, and an indoor heat exchanger.
  • a controller for switching between a blower for sending air, a cooling operation for cooling a target space, and a defrosting operation for controlling a defrosting section to remove frost adhering to an indoor heat exchanger is provided.
  • the control device starts defrosting operation based on the current value of the blower.
  • the defrosting operation is started based on the current value of the blower. Thereby, the timing of defrosting operation can be set appropriately.
  • FIG. 1 is a schematic diagram showing an example of a configuration of a refrigeration system according to Embodiment 1;
  • FIG. FIG. 2 is a schematic diagram showing an example of a configuration of a refrigerant circuit in the refrigeration system of FIG. 1;
  • 3 is a hardware configuration diagram showing an example of the configuration of a control device 3 in FIG. 2;
  • FIG. 4 is a diagram showing the relationship between the static pressure around the blower 22 and the rotation speed of the blower 22.
  • FIG. 4 is a diagram showing the relationship between the current value of the blower 22 and the rotation speed of the blower 22;
  • FIG. 4 is a diagram showing an example of current values of the blower 22 during cooling operation and defrosting operation;
  • FIG. 3 is a diagram showing an example of sensors arranged near an indoor heat exchanger 21.
  • FIG. 4 is a flowchart representing a procedure for determining the start and end of defrosting in Embodiment 1.
  • FIG. FIG. 9 is a flow chart showing the details of the processing in step S103 of FIG. 8;
  • FIG. 9 is a flowchart showing details of the process of step S104 of FIG. 8 in Embodiment 1.
  • FIG. FIG. 7 is a diagram showing defrosting start timing and defrosting end timing according to a second defrosting timing determination method in Embodiment 1;
  • FIG. 9 is a flow chart showing details of the process of step S104 of FIG. 8 in Embodiment 2.
  • FIG. 10 is a diagram showing defrosting start timing and defrosting end timing according to a second defrosting timing determination method in Embodiment 2; 9 is a flow chart showing details of the process of step S104 of FIG. 8 in Embodiment 3.
  • FIG. FIG. 11 is a diagram showing defrosting start timing and defrosting end timing according to a second defrosting timing determination method in Embodiment 3;
  • FIG. 11 is a schematic diagram showing an example of a configuration of a refrigerant circuit in a refrigeration system 200 according to Embodiment 4;
  • Embodiments will be described below with reference to the drawings.
  • Embodiment 1. A refrigeration system according to Embodiment 1 will be described.
  • the refrigeration system according to Embodiment 1 cools the target space by circulating the refrigerant in the refrigerant circuit.
  • FIG. 1 is a schematic diagram showing an example configuration of a refrigeration system 100 according to Embodiment 1.
  • the refrigeration system 100 includes an outdoor unit 1, an indoor unit 2, and a control device 3.
  • the indoor unit 2 is provided in the target space SP to be cooled.
  • the outdoor unit 1 and the indoor unit 2 are connected by refrigerant pipes 5 .
  • a copper pipe, for example, is used as the refrigerant pipe 5 .
  • heat insulation treatment may be performed by, for example, wrapping a heat insulating material around the copper pipe.
  • a space temperature sensor 4 is provided in the target space SP.
  • the space temperature sensor 4 measures the space temperature indicating the temperature of the target space SP. That is, the space temperature sensor 4 measures the intake air temperature of the air sucked into the indoor unit 2 .
  • a thermocouple, a thermistor, or the like, for example, is used as the space temperature sensor 4 .
  • FIG. 2 is a schematic diagram showing an example of the configuration of the refrigerant circuit in the refrigeration system 100 of FIG.
  • the outdoor unit 1 includes a compressor 11 , an outdoor heat exchanger 12 , an expansion valve 13 and an outdoor unit controller 10 .
  • the indoor unit 2 includes an indoor heat exchanger 21 , a fan 22 , a defrosting section 23 and an indoor unit control section 20 .
  • the compressor 11, the outdoor heat exchanger 12, the expansion valve 13, and the indoor heat exchanger 21 are sequentially connected in a loop by the refrigerant pipes 5 to form a refrigerant circuit in which the refrigerant circulates.
  • the configuration of the outdoor unit 1 and the indoor unit 2 shown in FIG. 2 is an example, and is not limited to this.
  • the outdoor unit 1 may be provided with an accumulator, a supercooling heat exchanger, and the like.
  • the expansion valve 13 is provided in the outdoor unit 1 in the example of FIG. 2, it is not limited to this.
  • the expansion valve 13 may be provided in the indoor unit 2 or may be provided in the refrigerant pipe 5 connecting between the outdoor heat exchanger 12 and the indoor heat exchanger 21 .
  • refrigerant circulating in the refrigerant circuit for example, a single refrigerant such as R-22 or R-134a, a quasi-azeotropic refrigerant such as R-410A or R-404A, or a non-covalent refrigerant such as R-407C or R-449A.
  • Evaporative mixed refrigerants or natural refrigerants such as CO2 or propane are used.
  • the compressor 11 sucks a low-temperature, low-pressure refrigerant, compresses the sucked-in refrigerant, and discharges a high-temperature, high-pressure refrigerant.
  • the compressor 11 may be, for example, an inverter compressor whose capacity, which is the output amount per unit time, is controlled by changing the operating frequency f, or may be one having a constant operating frequency f.
  • the operating frequency f when the compressor 11 is an inverter compressor is controlled by the controller 3 via the outdoor unit controller 10 .
  • the outdoor heat exchanger 12 exchanges heat between outdoor air supplied from an outdoor unit fan (not shown) and refrigerant discharged from the compressor 11, thereby dissipating the heat of the refrigerant to the outdoor air. Allow the refrigerant to condense. That is, the outdoor heat exchanger 12 functions as a condenser.
  • the outdoor heat exchanger 12 is not limited to such an air-cooling system, and for example, a water-cooling system in which heat is exchanged between water and a refrigerant may be used.
  • the expansion valve 13 expands the refrigerant.
  • the expansion valve 13 is configured by, for example, a valve whose degree of opening can be controlled, such as an electronic expansion valve.
  • the expansion valve 13 is an electronic expansion valve
  • the degree of opening of the expansion valve 13 is controlled by the control device 3 via the outdoor unit control section 10 .
  • the expansion valve 13 is not limited to an electronic expansion valve, and may be a mechanical expansion valve or a capillary.
  • the outdoor unit control unit 10 controls the compressor 11 and the expansion valve 13 based on commands from the control device 3 .
  • the outdoor unit control unit 10 is composed of a microcomputer or the like that executes various functions by executing software on an arithmetic device, or is composed of hardware such as a circuit device that realizes various functions.
  • the outdoor unit 1 includes a condensation temperature sensor 14, an evaporation temperature sensor 15 and a gas refrigerant temperature sensor 16.
  • the condensation temperature sensor 14 is provided on the discharge side of the compressor 11 and measures the condensation temperature CT of the refrigerant in the outdoor heat exchanger 12 .
  • the condensation temperature sensor 14 is not limited to a temperature sensor, and a pressure sensor, for example, may be used. In this case, the condensation temperature CT is obtained based on the high pressure measured by the condensation temperature sensor 14 and the type of refrigerant.
  • the condensation temperature sensor 14 may be provided at any position on the discharge side of the compressor 11 and on the upstream side of the expansion valve 13 .
  • the evaporation temperature sensor 15 is provided on the suction side of the compressor 11 and measures the evaporation temperature ET of the refrigerant in the indoor heat exchanger 21 .
  • the evaporation temperature sensor 15 is not limited to a temperature sensor, and may be a pressure sensor, for example. In this case, the evaporation temperature ET is obtained based on the low pressure measured by the evaporation temperature sensor 15 and the type of refrigerant.
  • the evaporation temperature sensor 15 may be provided at any position on the suction side of the compressor 11 and on the downstream side of the indoor heat exchanger 21 .
  • the gas refrigerant temperature sensor 16 is provided on the suction side of the compressor 11 and measures the temperature of the gas refrigerant sucked into the compressor 11 .
  • a thermocouple, a thermistor, or the like, for example, is used as the gas refrigerant temperature sensor 16 .
  • the indoor heat exchanger 21 exchanges heat between the indoor air, which is the air in the target space supplied from the blower 22 , and the refrigerant flowing out from the expansion valve 13 of the outdoor unit 1 . Thereby, the cooling air supplied to the target space SP is generated. That is, the indoor heat exchanger 21 functions as an evaporator.
  • the blower 22 supplies air to the indoor heat exchanger 21 .
  • the rotation speed of the blower 22 is measured by the controller 3 via the indoor unit controller 20 .
  • the current value of the blower 22 specifically the current value of the fan motor that constitutes the blower 22 is calculated.
  • a centrifugal fan or a multi-blade fan driven by a motor such as a DC (Direct Current) fan motor is used.
  • the defrosting section 23 defrosts the indoor heat exchanger 21 .
  • a defrosting method of the defrosting unit 23 for example, a heater method of melting frost with heat of a heater or a water spraying method of spraying water on the indoor heat exchanger 21 and melting frost with the heat of water is used.
  • an off-cycle method or the like is used in which the frost is melted by stopping the refrigerating cycle operation and supplying ambient air to the frosted indoor heat exchanger 21 by the blower 22. may be ON/OFF of the defrosting section 23 is controlled by the control device 3 via the indoor unit control section 20 .
  • the indoor unit control section 20 controls the blower 22 and the defrosting section 23 based on commands from the control device 3 .
  • the indoor unit control unit 20 is composed of a microcomputer or the like that executes various functions by executing software on an arithmetic device, or is composed of hardware such as a circuit device that realizes various functions.
  • the control device 3 controls the driving frequency of the compressor 11 to control the amount of refrigerant discharged by the compressor 11 per unit time.
  • the control device 3 controls the degree of opening of the expansion valve 13 so that the degree of superheat of the refrigerant flowing out of the indoor unit 2 is within a desired range.
  • the control device 3 controls the blower 22 and the defrosting section 23 provided in the indoor unit 2 via the indoor unit control section 20 .
  • the control device 3 determines the optimal defrosting operation start timing, and controls each part so that the defrosting operation is performed at the determined defrosting start timing.
  • the control device 3 controls the entire refrigeration system 100 .
  • FIG. 3 is a hardware configuration diagram showing an example of the configuration of the control device 3 in FIG.
  • the control device 3 includes a processing circuit 31 , a memory 32 and an input/output section 33 .
  • the processing circuit 31 may be dedicated hardware, or may be a CPU (Central Processing Unit) that executes a program stored in the memory 32 .
  • the processing circuit 31 is a CPU, the functions of the control device 3 are realized by software.
  • Software is written as a program and stored in the memory 32 .
  • the processing circuit 31 reads and executes a program stored in the memory 32 .
  • the memory 32 includes nonvolatile or volatile semiconductor memory (for example, RAM (Random Access Memory), ROM (Read Only Memory), flash memory, etc.). It is also called a processor, microcomputer, processor, or DSP (Digital Signal Processor).
  • cooling operation The operation when the cooling operation is performed by the refrigeration system 100 will be described.
  • a low-temperature, low-pressure refrigerant is compressed by the compressor 11 and discharged as a high-temperature, high-pressure gas refrigerant.
  • the high-temperature and high-pressure gas refrigerant discharged from the compressor 11 exchanges heat with a medium such as air or water passing through the outdoor heat exchanger 12, condenses, becomes a high-pressure liquid refrigerant, and flows out of the outdoor heat exchanger 12. do.
  • the high-pressure liquid refrigerant that has flowed out of the outdoor heat exchanger 12 flows into the expansion valve 13 .
  • the high-pressure liquid refrigerant that has flowed into the expansion valve 13 is decompressed to become a low-temperature, low-pressure gas-liquid two-phase refrigerant, and flows out of the outdoor unit 1 .
  • the low-temperature, low-pressure gas-liquid two-phase refrigerant flowing out of the outdoor unit 1 flows into the indoor unit 2 via the refrigerant pipe 5 .
  • the low-temperature, low-pressure gas-liquid two-phase refrigerant that has flowed into the indoor unit 2 flows into the indoor heat exchanger 21 .
  • the low-temperature, low-pressure gas-liquid two-phase refrigerant that has flowed into the indoor heat exchanger 21 exchanges heat with indoor air, absorbs heat, evaporates, and flows out of the indoor heat exchanger 21 as a low-temperature, low-pressure gas refrigerant.
  • the low-temperature, low-pressure gas refrigerant that has flowed out of the indoor heat exchanger 21 flows out of the indoor unit 2 .
  • the low-temperature, low-pressure gas refrigerant flowing out of the indoor unit 2 flows into the outdoor unit 1 through the refrigerant pipe 5 and is sucked into the compressor 11 .
  • frost forms on the indoor heat exchanger 21 . If the cooling operation is continued while the indoor heat exchanger 21 is frosted, the amount of frost increases and the static pressure of the blower 22 increases.
  • FIG. 4 is a diagram showing the relationship between the static pressure around the blower 22 and the rotational speed of the blower 22. As shown in FIG. As shown in FIG. 4, the higher the static pressure (air pressure) around the blower 22, the lower the rotation speed of the blower 22. As shown in FIG. As the static pressure (air pressure) around the blower 22 decreases, the rotation speed of the blower 22 increases.
  • the air outlet of the housing of the indoor unit 2 is blocked, pressure loss occurs, and airflow becomes difficult.
  • the indoor heat exchanger 21 is blocked from frosting the air to be discharged to the outside, the static pressure around the fan 22 increases, and the rotation speed of the fan 22 decreases.
  • the air volume of the blower 22 decreases, making it difficult to draw in air from the outside and to exhaust the air inside the housing.
  • FIG. 5 is a diagram showing the relationship between the current value of the blower 22 and the rotation speed of the blower 22.
  • the current value of the fan 22 current consumption of the fan 22
  • frost builds up on the indoor heat exchanger 21
  • the air outlet of the housing of the indoor unit 2 is blocked, and when the static pressure around the blower 22 increases, the rotation speed of the blower 22 decreases.
  • the current value of the blower 22 increases due to the decrease in the rotational speed of the blower 22 .
  • FIG. 6 is a diagram showing an example of current values of the blower 22 during cooling operation and defrosting operation.
  • the horizontal axis indicates the time t
  • the vertical axis indicates the current value of the blower 22 when the defrosting operation time is Ta and the cooling operation time is Tb in the refrigeration system 100 .
  • the cooling operation time Tb is short, the cooling operation time will be short, so the inside of the refrigerator may not reach the target temperature.
  • the cooling operation time Tb When the cooling operation time Tb is long, the cooling operation time becomes long, so the amount of frost formed on the indoor heat exchanger 21 becomes excessive. That is, when the cooling operation time Tb is long, the heat transfer performance of the indoor heat exchanger 21 is lowered due to frost formation, and cooling may not be sufficient.
  • the defrosting start timing of the indoor heat exchanger 21 is optimized in order to prevent the decrease in cooling capacity as described above.
  • the control device 3 switches between the defrosting operation and the cooling operation using the first defrosting timing determination method when the current time is included in the determined time period.
  • the controller 3 uses ET (Exit Temperature) shift control to determine the defrost start timing, and records the current value of the blower 22 at that time as the defrost start threshold value THs. do.
  • ET Exit Temperature
  • the control device 3 uses the ET shift control to determine the defrosting end timing, and sets the current value of the blower at that time as the defrosting end threshold THe. Record.
  • the control device 3 switches between the defrosting operation and the cooling operation using the second defrosting timing determination method.
  • the control device 3 switches between the defrosting operation and the cooling operation using the defrosting start threshold THs and the defrosting end threshold THe obtained by the ET shift control.
  • the set time period is a time period when there are few people coming and going, such as at night.
  • RT-ET temperature difference between the blowout temperature of the air in the indoor heat exchanger 21, which is an evaporator
  • ET of the refrigerant in the indoor heat exchanger 21 to the threshold value TH1.
  • FIG. 7 is a diagram showing an example of sensors arranged near the indoor heat exchanger 21.
  • Evaporation temperature ET can be measured by using temperature sensor 41 on the inlet side of indoor heat exchanger 21 or by converting pressure detected by pressure sensor 43 on the outlet side into saturated gas temperature. .
  • the present embodiment it is possible to switch between the defrosting operation and the cooling operation by controlling the current value of the blower 22 during the daytime when many people come and go, and by ET shift control during the nighttime when few people come and go.
  • the defrosting operation cannot be performed at an accurate timing with the ET shift control, such as during the day when there are many people coming and going, the fan motor current value control becomes possible, so the optimum defrosting operation can always be performed.
  • the current value of the blower 22 measured during the ET shift control is set to the defrosting start threshold and A defrost end threshold can be set.
  • FIG. 8 is a flowchart representing the procedure for determining the start and end of defrosting in the first embodiment. The flowchart process of FIG. 8 is always executed while the refrigeration system 100 is in operation.
  • step S101 the control device 3 starts the cooling operation of the refrigeration system 100.
  • step S102 when the current time is included in the determined time zone, the process proceeds to step S103, and when the current time is not included in the determined time zone, the process proceeds to step S104. .
  • step S103 the control device 3 switches between the defrosting operation and the cooling operation using the first defrosting timing determination method.
  • step S104 the control device 3 switches between the defrosting operation and the cooling operation using the second defrosting timing determination method.
  • FIG. 9 is a flow chart showing the details of the processing in step S103 of FIG.
  • the control device 3 acquires the blowing temperature RT of the air in the indoor heat exchanger 21 and the evaporation temperature ET of the refrigerant in the indoor heat exchanger 21 .
  • TH1 is, for example, 5°C.
  • step S504 the control device 3 ends the cooling operation of the refrigeration system 100, starts the defrosting operation, and acquires the current value Is of the blower 22.
  • step S505 the acquired current value Is of the blower 22 is recorded as the defrosting start threshold THs.
  • step S506 the control device 3 acquires the blowout temperature RT of the air in the indoor heat exchanger 21 and the evaporation temperature ET of the refrigerant in the indoor heat exchanger 21.
  • step S508 the control device 3 ends the defrosting operation of the refrigeration system 100, starts the cooling operation, and acquires the current value Is of the blower 22.
  • step S509 the acquired current value of the blower 22 is recorded as the defrosting end threshold THe.
  • FIG. 10 is a flow chart showing the details of the process of step S104 in FIG. 8 in the first embodiment.
  • FIG. 11 is a diagram showing defrosting start timing and defrosting end timing according to the second defrosting timing determination method in the first embodiment.
  • step S1 the control device 3 determines whether or not the current value Is of the blower 22 exceeds the defrosting start threshold THs. When the current value Is of the blower 22 exceeds the defrosting start threshold THs, the process proceeds to step S2. When the current value Is of the blower 22 does not exceed the defrosting start threshold THs, the control device 3 continues the cooling operation of the refrigeration system 100 .
  • step S2 the control device 3 ends the cooling operation of the refrigeration system 100 and starts the defrosting operation of the refrigeration system 100.
  • step S3 when a certain period of time ⁇ t has passed since the defrosting operation started, the process proceeds to step S4.
  • the control device 3 allows the refrigeration system 100 to continue the defrosting operation when the predetermined time ⁇ t has not elapsed since the defrosting operation was started.
  • step S4 the control device 3 terminates the defrosting operation of the refrigeration system 100 and starts the cooling operation of the refrigeration system 100.
  • the temperature efficiency threshold is set in advance according to the type of refrigerator. Objects to be cooled are placed in the freezer, and it is assumed that workers enter and leave the freezer. Therefore, even if the type of refrigerator is the same, the actual use environment differs from refrigerator to refrigerator.
  • the defrosting start threshold value and the defrosting end threshold value that determine the switching timing between the defrosting operation and the cooling operation based on the current value of the blower are the switching timing between the defrosting operation and the cooling operation based on the ET shift control. Use the current value of the blower in This makes it possible to appropriately set the timing of the defrosting operation according to the actual use environment.
  • FIG. 12 is a flow chart showing details of the process of step S104 in FIG. 8 in the second embodiment.
  • FIG. 13 is a diagram showing defrosting start timing and defrosting end timing according to the second defrosting timing determination method in the second embodiment.
  • step S11 the control device 3 determines whether or not the current value Is of the blower 22 exceeds the defrosting start threshold THs. When the current value Is of the blower 22 exceeds the defrosting start threshold THs, the process proceeds to step S12. When the current value Is of the blower 22 does not exceed the defrosting start threshold THs, the control device 3 continues the cooling operation of the refrigeration system 100 .
  • step S ⁇ b>12 the control device 3 ends the cooling operation of the refrigeration system 100 and starts the defrosting operation of the refrigeration system 100 .
  • the control device 3 causes the off-cycle defrosting to be performed while the air blower 22 is being rotated.
  • step S13 the control device 3 determines whether or not the current value Is of the blower 22 is less than the defrosting end threshold THe.
  • the process proceeds to step S14.
  • the control device 3 continues the defrosting operation of the refrigeration system 100 .
  • the defrosting end threshold THe can be set by visually confirming the progress of defrosting of the indoor heat exchanger 21 during trial operation.
  • the refrigeration system 100 may be operated while changing the defrosting end threshold THe during trial operation, and the defrosting end threshold THe at which efficiency is maximized may be used in actual operation.
  • step S14 the control device 3 terminates the defrosting operation of the refrigeration system 100 and starts the cooling operation of the refrigeration system 100.
  • the defrost start threshold and the defrost end threshold it is possible to reliably return the cooling capacity of the refrigeration system to a state close to the initial state.
  • FIG. 14 is a flow chart showing details of the process of step S104 of FIG. 8 in the third embodiment.
  • FIG. 15 is a diagram showing defrosting start timing and defrosting end timing according to the second defrosting timing determination method in the third embodiment.
  • step S21 the control device 3 determines whether or not the current value Is of the blower 22 exceeds the defrosting start threshold THs. When the current value Is of the blower 22 exceeds the defrosting start threshold THs, the process proceeds to step S22. When the current value Is of the blower 22 does not exceed the defrosting start threshold THs, the control device 3 continues the cooling operation of the refrigeration system 100 .
  • step S22 the control device 3 terminates the cooling operation of the refrigeration system 100, starts the defrosting operation of the refrigeration system 100, and stops the rotation of the blower 22.
  • step S23 when the fixed time ⁇ t has passed, the process proceeds to step S4. If the fixed time ⁇ t has not passed, the control device 3 continues the defrosting operation of the refrigeration system 100 .
  • step S ⁇ b>24 the control device 3 starts rotating the blower 22 .
  • step S25 the control device 3 determines whether or not the current value Is of the blower 22 is less than the defrosting end threshold value THe. When the current value Is of the blower 22 is less than the defrosting end threshold value THe, the process proceeds to step S26. If the current value Is of the blower 22 is not less than the defrosting end threshold value THe, the process proceeds to step S27.
  • step S27 the control device 3 stops the rotation of the blower 22. After that, the process returns to step S23.
  • step S26 the control device 3 terminates the defrosting operation of the refrigeration system 100, stops the rotation of the blower 22, and starts the cooling operation of the refrigeration system 100.
  • FIG. 16 is a schematic diagram showing an example of the configuration of a refrigerant circuit in a refrigeration system 200 according to Embodiment 4.
  • a refrigeration system 200 includes an outdoor unit 201 , an indoor unit 202 and a control device 3 .
  • the outdoor unit 201 includes a compressor 11 , an outdoor heat exchanger 12 , an expansion valve 13 , a condensation temperature sensor 14 , an evaporation temperature sensor 15 , a gas refrigerant temperature sensor 16 and an outdoor unit controller 10 , similar to the outdoor unit 1 .
  • the outdoor unit 201 further includes a bypass circuit 17 and a bypass valve 18 .
  • the bypass circuit 17 branches from the refrigerant pipe 5 on the discharge side of the compressor 11 and is connected to the refrigerant pipe 5 between the expansion valve 13 and the indoor heat exchanger 21 .
  • the bypass circuit 17 is provided so that part of the refrigerant discharged from the compressor 11 flows into the indoor heat exchanger 21 .
  • a bypass valve 18 is provided in the bypass circuit 17 .
  • the opening/closing of the bypass valve 18 is controlled by the control device 3 via the outdoor unit control section 10, and the opening/closing of the bypass valve 18 circulates or blocks the refrigerant flowing through the bypass circuit 17.
  • the indoor unit 202 includes an indoor heat exchanger 21, an air blower 22, and an indoor unit controller 20, similar to the indoor unit 2. Unlike the indoor unit 2 , the indoor unit 202 is not provided with the defrosting unit 23 .
  • the control device 3 opens the bypass valve 18 during the defrosting operation. As a result, part of the high-temperature, high-pressure gas refrigerant discharged from the compressor 11 flows through the bypass valve 18 and flows into the indoor heat exchanger 21 of the indoor unit 202 . When the high-temperature gas refrigerant flows into the indoor heat exchanger 21, frost adhering to the indoor heat exchanger 21 is melted and removed by the heat of the refrigerant.
  • the indoor heat exchanger 21 can be defrosted by providing the bypass circuit 17 and the bypass valve 18 instead of the defrosting section 23 .
  • the defrosting unit 23 is removed, but the configuration is not limited to this, and the defrosting unit 23 may be used together.
  • bypass circuit 17 and the bypass valve 18 are used as the defrosting section 23 in the refrigeration system 200 of the present embodiment.
  • the high-temperature refrigerant flows into the indoor heat exchanger 21, so frost adhering to the indoor heat exchanger 21 can be removed.

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PCT/JP2021/002785 2021-01-27 2021-01-27 冷凍システム Ceased WO2022162776A1 (ja)

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JP2018189340A (ja) * 2017-05-11 2018-11-29 ホシザキ株式会社 冷却貯蔵庫

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