WO2022162776A1 - Refrigeration system - Google Patents

Refrigeration system 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
Application number
PCT/JP2021/002785
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French (fr)
Japanese (ja)
Inventor
歩 江上
達也 ▲雑▼賀
Original Assignee
三菱電機株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to JP2022577869A priority Critical patent/JP7412608B2/en
Priority to PCT/JP2021/002785 priority patent/WO2022162776A1/en
Publication of WO2022162776A1 publication Critical patent/WO2022162776A1/en

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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.

Abstract

According to the present invention, when the current time is included in a predetermined time slot, a control device (3) initiates defrosting operation on the basis of the blow-out temperature of air in an indoor heat exchanger (21) and the evaporation temperature of a refrigerant in the indoor heat exchanger (21) during cooling operation, measures the electric current value of an air blower (22), and sets the measured electric current value as a defrosting initiation threshold. The control device (3) initiates defrosting operation on the basis of the electric current value of the air blower (22).

Description

冷凍システムrefrigeration system
　本開示は、冷凍システムに関する。 The present disclosure relates to refrigeration systems.
　従来から、除霜運転を適切なタイミングで開始することができる冷凍機が知られている（例えば、特許文献１参照）。この冷凍機は、冷凍サイクルの一部を構成する熱交換器を流れる冷媒の温度と、熱交換器を通過する空気の吸い込み温度および吹出温度との測定結果に基づいて冷媒と空気の熱交換の効率を表す温度効率を算出する。この冷凍機は、算出された温度効率の冷却運転開始からの変化傾向に基づいて予測された熱交換器への着霜量と、冷凍機の機種に応じて予め設定された温度効率の閾値とから最適除霜開始タイミングを判定する。この冷凍機は、温度効率が閾値以上になったときに除霜運転を開始する。 Conventionally, 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.
特開２００７－２２５１５８号公報JP 2007-225158 A
　特許文献１では、除霜運転のタイミングを決定するために、温度効率を計算しなければならない。 In Patent Document 1, temperature efficiency must be calculated in order to determine the timing of defrosting operation.
　本開示の目的は、温度効率以外の方法で、除霜運転のタイミングを適切に設定することができる冷凍システムを提供することである。 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.
　本開示の冷凍システムは、環状に接続された圧縮機、室外熱交換器、膨張弁および室内熱交換器と、室内熱交換器に付着した霜を除去する除霜部と、室内熱交換器に空気を送る送風機と、対象空間を冷却する冷却運転と、除霜部を制御して室内熱交換器に付着した霜を除去する除霜運転とを切り替える制御装置と備える。制御装置は、送風機の電流値に基づいて、除霜運転を開始する。 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.
　本開示によれば、送風機の電流値に基づいて、除霜運転を開始する。これにより、除霜運転のタイミングを適切に設定することができる。 According to the present disclosure, the defrosting operation is started based on the current value of the blower. Thereby, the timing of defrosting operation can be set appropriately.
実施の形態１に係る冷凍システムの構成の一例を示す概略図である。1 is a schematic diagram showing an example of a configuration of a refrigeration system according to Embodiment 1; FIG. 図１の冷凍システムにおける冷媒回路の構成の一例を示す概略図である。FIG. 2 is a schematic diagram showing an example of a configuration of a refrigerant circuit in the refrigeration system of FIG. 1; 図２の制御装置３の構成の一例を示すハードウェア構成図である。3 is a hardware configuration diagram showing an example of the configuration of a control device 3 in FIG. 2; FIG. 送風機２２の周囲の静圧と送風機２２の回転数との関係を示す図である。4 is a diagram showing the relationship between the static pressure around the blower 22 and the rotation speed of the blower 22. FIG. 送風機２２の電流値と送風機２２の回転数との関係を示す図である。4 is a diagram showing the relationship between the current value of the blower 22 and the rotation speed of the blower 22; FIG. 冷却運転時および除霜運転時の送風機２２の電流値の一例を示す図である。4 is a diagram showing an example of current values of the blower 22 during cooling operation and defrosting operation; FIG. 室内熱交換器２１の近傍に配置されるセンサの例を表わす図である。FIG. 3 is a diagram showing an example of sensors arranged near an indoor heat exchanger 21. FIG. 実施の形態１における、除霜開始および除霜終了の判定手順を表わすフローチャートである。4 is a flowchart representing a procedure for determining the start and end of defrosting in Embodiment 1. FIG. 図８のステップＳ１０３の処理の詳細を表わすフローチャートである。FIG. 9 is a flow chart showing the details of the processing in step S103 of FIG. 8; FIG. 実施の形態１における、図８のステップＳ１０４の処理の詳細を表わすフローチャートである。FIG. 9 is a flowchart showing details of the process of step S104 of FIG. 8 in Embodiment 1. FIG. 実施の形態１における第２の除霜タイミング決定方法による除霜開始タイミングおよび除霜終了タイミングを表わす図である。FIG. 7 is a diagram showing defrosting start timing and defrosting end timing according to a second defrosting timing determination method in Embodiment 1; 実施の形態２における、図８のステップＳ１０４の処理の詳細を表わすフローチャートである。FIG. 9 is a flow chart showing details of the process of step S104 of FIG. 8 in Embodiment 2. FIG. 実施の形態２における第２の除霜タイミング決定方法による除霜開始タイミングおよび除霜終了タイミングを表わす図である。FIG. 10 is a diagram showing defrosting start timing and defrosting end timing according to a second defrosting timing determination method in Embodiment 2; 実施の形態３における、図８のステップＳ１０４の処理の詳細を表わすフローチャートである。9 is a flow chart showing details of the process of step S104 of FIG. 8 in Embodiment 3. FIG. 実施の形態３における第２の除霜タイミング決定方法による除霜開始タイミングおよび除霜終了タイミングを表わす図である。FIG. 11 is a diagram showing defrosting start timing and defrosting end timing according to a second defrosting timing determination method in Embodiment 3; 実施の形態４に係る冷凍システム２００における冷媒回路の構成の一例を示す概略図である。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;
　以下、実施の形態について、図面を参照して説明する。
　実施の形態１．
　実施の形態１に関わる冷凍システムについて説明する。実施の形態１に係る冷凍システムは、冷媒回路に冷媒を循環させることにより、対象空間を冷却する。 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.
　図１は、実施の形態１に係る冷凍システムの１００の構成の一例を示す概略図である。図１に示すように、冷凍システム１００は、室外機１、室内機２および制御装置３を備える。室内機２は、冷却対象となる対象空間ＳＰに設けられている。室外機１と室内機２とは、冷媒配管５で接続されている。冷媒配管５として、例えば銅配管が用いられる。周辺の空気との熱交換を抑制するために、銅配管の周囲に断熱材を巻くなどして断熱処理が施されても良い。 FIG. 1 is a schematic diagram showing an example configuration of a refrigeration system 100 according to Embodiment 1. FIG. As shown in FIG. 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 . In order to suppress heat exchange with the surrounding air, heat insulation treatment may be performed by, for example, wrapping a heat insulating material around the copper pipe.
　対象空間ＳＰには、空間温度センサ４が設けられている。空間温度センサ４は、対象空間ＳＰの温度を示す空間温度を計測する。すなわち、空間温度センサ４は、室内機２に吸い込まれる空気の吸込み空気温度を計測する。空間温度センサ４として、例えば熱電対またはサーミスタ等が用いられる。 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 .
　図２は、図１の冷凍システム１００における冷媒回路の構成の一例を示す概略図である。 FIG. 2 is a schematic diagram showing an example of the configuration of the refrigerant circuit in the refrigeration system 100 of FIG.
　室外機１は、圧縮機１１、室外熱交換器１２、膨張弁１３および室外機制御部１０を備える。室内機２は、室内熱交換器２１、送風機２２、除霜部２３および室内機制御部２０を備える。圧縮機１１、室外熱交換器１２、膨張弁１３および室内熱交換器２１が冷媒配管５によって順次環状に接続されることにより、冷媒が循環する冷媒回路が形成される。 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.
　図２に示す室外機１および室内機２の構成は一例であり、これに限られない。例えば、室外機１にアキュムレータおよび過冷却熱交換器等が設けられても良い。図２の例では、膨張弁１３が室外機１に設けられているが、これに限られない。膨張弁１３が室内機２に設けられても良いし、室外熱交換器１２と室内熱交換器２１との間を接続する冷媒配管５に設けられても良い。 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. For example, the outdoor unit 1 may be provided with an accumulator, a supercooling heat exchanger, and the like. Although 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 .
　冷媒回路を循環する冷媒として、例えばＲ－２２またはＲ－１３４ａなどの単一冷媒、あるいはＲ－４１０ＡまたはＲ－４０４Ａなどの疑似共沸混合冷媒、あるいはＲ―４０７ＣまたはＲ－４４９Ａなどの非共沸混合冷媒、あるいはＣＯ２またはプロパンなどの自然冷媒が用いられる。 As the 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.
　次に、室外機１の動作を説明する。
　圧縮機１１は、低温低圧の冷媒を吸入し、吸入した冷媒を圧縮し、高温高圧の冷媒を吐出する。圧縮機１１は、例えば、運転周波数ｆを変化させることにより、単位時間当たりの送出量である容量が制御されるインバータ圧縮機でも良いし、運転周波数ｆが一定のものでも良い。圧縮機１１がインバータ圧縮機である場合の運転周波数ｆは、室外機制御部１０を介して制御装置３によって制御される。 Next, the operation of the outdoor unit 1 will be explained.
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 .
　室外熱交換器１２は、図示しない室外機ファンから供給される室外空気と、圧縮機１１から吐出された冷媒との間で熱交換を行わせることによって、冷媒の熱を室外空気に放熱して冷媒を凝縮させる。すなわち、室外熱交換器１２は、凝縮器として機能する。なお、室外熱交換器１２は、このような空冷方式に限られず、例えば水と冷媒との間で熱交換を行う水冷方式が用いられても良い。 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. In addition, 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.
　膨張弁１３は、冷媒を膨張させる。膨張弁１３は、例えば、電子式膨張弁などの開度の制御が可能な弁で構成される。膨張弁１３が電子式膨張弁の場合に、膨張弁１３の開度は、室外機制御部１０を介して制御装置３によって制御される。膨張弁１３は、電子式膨張弁に限定されるものではなく、機械式膨張弁またはキャピラリによって構成されてもよい。 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. When 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.
　室外機制御部１０は、制御装置３からの指令に基づき、圧縮機１１および膨張弁１３を制御する。室外機制御部１０は、演算装置上でソフトウェアを実行することによって各種機能を実行するマイクロコンピュータ等で構成され、もしくは各種機能を実現する回路デバイスなどのハードウェア等で構成されている。 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.
　室外機１は、凝縮温度センサ１４、蒸発温度センサ１５およびガス冷媒温度センサ１６を備える。 The outdoor unit 1 includes a condensation temperature sensor 14, an evaporation temperature sensor 15 and a gas refrigerant temperature sensor 16.
　凝縮温度センサ１４は、圧縮機１１の吐出側に設けられ、室外熱交換器１２における冷媒の凝縮温度ＣＴを計測する。凝縮温度センサ１４として、温度センサに限られず、例えば圧力センサが用いられても良い。この場合、凝縮温度センサ１４で計測された高圧圧力と冷媒の種類とに基づき、凝縮温度ＣＴが得られる。凝縮温度センサ１４は、圧縮機１１の吐出側であって、膨張弁１３の上流側であれば、いずれの位置に設けられても良い。 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 .
　蒸発温度センサ１５は、圧縮機１１の吸入側に設けられ、室内熱交換器２１における冷媒の蒸発温度ＥＴを計測する。蒸発温度センサ１５として、温度センサに限られず、例えば圧力センサが用いられても良い。この場合、蒸発温度センサ１５で計測された低圧圧力と冷媒の種類とに基づき、蒸発温度ＥＴが得られる。蒸発温度センサ１５は、圧縮機１１の吸入側であって、室内熱交換器２１の下流側であれば、いずれの位置に設けられても良い。 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 .
　ガス冷媒温度センサ１６は、圧縮機１１の吸入側に設けられ、圧縮機１１に吸入されるガス冷媒の温度を計測する。ガス冷媒温度センサ１６として、例えば熱電対またはサーミスタ等が用いられる。 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 .
　次に、室内機２の動作を説明する。
　室内熱交換器２１は、送風機２２から供給される対象空間の空気である室内空気と、室外機１の膨張弁１３から流出した冷媒との間で熱交換を行う。これにより、対象空間ＳＰに供給される冷却空気が生成される。すなわち、室内熱交換器２１は、蒸発器として機能する。 Next, the operation of the indoor unit 2 will be explained.
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.
　送風機２２は、室内熱交換器２１に対して空気を供給する。送風機２２の回転数は、室内機制御部２０を介して制御装置３によって計測される。送風機２２の回転数が計測されることにより、送風機２２の電流値、具体的には送風機２２を構成するファンモータの電流値が算出される。送風機２２として、例えばＤＣ（Direct　Current）ファンモータなどのモータによって駆動される遠心ファンまたは多翼ファン等が用いられる。 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 . By measuring the rotation speed of the blower 22, the current value of the blower 22, specifically the current value of the fan motor that constitutes the blower 22 is calculated. As the air blower 22, for example, a centrifugal fan or a multi-blade fan driven by a motor such as a DC (Direct Current) fan motor is used.
　除霜部２３は、室内熱交換器２１を除霜する。
　除霜部２３の除霜方式として、例えばヒータの熱によって霜を溶かすヒータ方式、あるいは、室内熱交換器２１に水を散水し、水の熱によって霜を溶かす散水方式が用いられる。あるいは、除霜部２３の除霜方式として、冷凍サイクル運転を停止して、着霜している室内熱交換器２１に送風機２２によって周辺空気を供給することによって霜を溶かすオフサイクル方式等が用いられてもよい。除霜部２３のＯＮ／ＯＦＦは、室内機制御部２０を介して制御装置３によって制御される。 The defrosting section 23 defrosts the indoor heat exchanger 21 .
As 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. Alternatively, as a defrosting method of the defrosting unit 23, 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 .
　室内機制御部２０は、制御装置３からの指令に基づき、送風機２２および除霜部２３を制御する。室内機制御部２０は、演算装置上でソフトウェアを実行することによって各種機能を実行するマイクロコンピュータ等で構成され、もしくは各種機能を実現する回路デバイスなどのハードウェア等で構成されている。 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.
　次に、制御装置３の動作を説明する。
　制御装置３は、圧縮機１１の駆動周波数を制御して、圧縮機１１が単位時間当たりに吐出する冷媒量を制御する。制御装置３は、室内機２から流出する冷媒の過熱度が所望の範囲となるように、膨張弁１３の開度を制御する。制御装置３は、室内機制御部２０を介して室内機２に設けられた送風機２２および除霜部２３を制御する。さらに、本実施の形態において、制御装置３は、最適な除霜運転の開始時期を決定し、決定した除霜開始時期に除霜運転を行うように、各部を制御する。制御装置３は、冷凍システム１００の全体を制御する。 Next, the operation of the control device 3 will be explained.
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 . Furthermore, in the present embodiment, 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 .
　図３は、図２の制御装置３の構成の一例を示すハードウェア構成図である。制御装置３は、処理回路３１と、メモリ３２と、入出力部３３とを含む。処理回路３１は、専用のハードウェアであってもよいし、メモリ３２に格納されるプログラムを実行するＣＰＵ（Central　Processing　Unit）であってもよい。処理回路３１がＣＰＵの場合、制御装置３の機能は、ソフトウェアにより実現される。ソフトウェアはプログラムとして記述され、メモリ３２に格納される。処理回路３１は、メモリ３２に記憶されたプログラムを読み出して実行する。メモリ３２には、不揮発性または揮発性の半導体メモリ（たとえばＲＡＭ（Random　Access　Memory）、ＲＯＭ（Read　Only　Memory）、フラッシュメモリ等が含まれる。ＣＰＵは、中央処理装置、処理装置、演算装置、マイクロプロセッサ、マイクロコンピュータ、プロセッサ、あるいはＤＳＰ（Digital　Signal　Processor）とも呼ばれる。 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 . When 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).
　次に、上記構成を有する冷凍システム１００の動作について説明する。冷却運転時の動作と、最適な除霜開始時期の決定方法とについて説明する。 Next, the operation of the refrigeration system 100 having the above configuration will be described. The operation during the cooling operation and the method of determining the optimal defrosting start time will be described.
　（冷却運転）
　冷凍システム１００によって冷却運転が行われる場合の動作について説明する。室外機１において、低温低圧の冷媒が圧縮機１１によって圧縮され、高温高圧のガス冷媒となって吐出される。圧縮機１１から吐出された高温高圧のガス冷媒は、室外熱交換器１２を通過する空気または水などの媒体と熱交換して凝縮し、高圧の液冷媒となって室外熱交換器１２から流出する。 (cooling operation)
The operation when the cooling operation is performed by the refrigeration system 100 will be described. In the outdoor unit 1, 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.
　室外熱交換器１２から流出した高圧の液冷媒は、膨張弁１３に流入する。膨張弁１３に流入した高圧の液冷媒は、減圧されて低温低圧の気液二相冷媒となり、室外機１から流出する。室外機１から流出した低温低圧の気液二相冷媒は、冷媒配管５を介して室内機２に流入する。 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 .
　室内機２に流入した低温低圧の気液二相冷媒は、室内熱交換器２１に流入する。室内熱交換器２１に流入した低温低圧の気液二相冷媒は、室内空気と熱交換して吸熱及び蒸発し、低温低圧のガス冷媒となって室内熱交換器２１から流出する。室内熱交換器２１から流出した低温低圧のガス冷媒は、室内機２から流出する。室内機２から流出した低温低圧のガス冷媒は、冷媒配管５を介して室外機１に流入し、圧縮機１１に吸入される。 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 .
　（最適な除霜開始時期の決定方法）
　次に、最適な時期に除霜運転を開始する決定方法について説明する。 (Method for determining optimum defrosting start time)
Next, a method of determining when to start the defrosting operation at the optimum time will be described.
　室内熱交換器２１の温度が氷点下の状態で冷却運転が長時間行われる場合、室内熱交換器２１が着霜する。室内熱交換器２１が着霜した状態で冷却運転が継続されると、着霜量が増加して、送風機２２の静圧が増加する。 When the cooling operation is performed for a long time while the temperature of the indoor heat exchanger 21 is below freezing, 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.
　図４は、送風機２２の周囲の静圧と送風機２２の回転数との関係を示す図である。
　図４に示すように、送風機２２の周囲の静圧（空気の圧力）が大きいほど、送風機２２の回転数は小さくなる。送風機２２の周囲の静圧（空気の圧力）が小さいほど、送風機２２の回転数は大きくなる。 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.
　室内熱交換器２１の着霜が進行することによって、室内機２の筐体の空気の出口が閉塞し、圧力損失が起こり、風が通りにくくなる。室外に排出する空気が室内熱交換器２１の着霜によって防がれると、送風機２２の周囲の静圧が上昇するため、送風機２２の回転数は低下する。送風機２２の回転数が低下すると、送風機２２の風量が小さくなるので、外部から空気の吸込みが困難になり、筐体の中にある空気の排出が困難になる。 As frost builds up on the indoor heat exchanger 21, the air outlet of the housing of the indoor unit 2 is blocked, pressure loss occurs, and airflow becomes difficult. When 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. When the number of revolutions of the blower 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.
　図５は、送風機２２の電流値と送風機２２の回転数との関係を示す図である。
　図５に示すように、送風機２２の回転数が小さくなると、送風機２２の電流値（送風機２２の消費電流）は大きくなる。室内熱交換器２１の着霜が進行することによって、室内機２の筐体の空気の出口が閉塞して、送風機２２の周囲の静圧が増加した場合、送風機２２の回転数が減少する。送風機２２の回転数の減少によって、送風機２２の電流値が増加する。 FIG. 5 is a diagram showing the relationship between the current value of the blower 22 and the rotation speed of the blower 22. As shown in FIG.
As shown in FIG. 5, when the rotational speed of the fan 22 decreases, the current value of the fan 22 (current consumption of the fan 22) increases. As 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 .
　したがって、室内熱交換器２１が着霜した場合には、室内熱交換器２１に付着した霜を溶かして除去する除霜運転が行われる。 Therefore, when the indoor heat exchangers 21 are frosted, a defrosting operation is performed to melt and remove the frost adhering to the indoor heat exchangers 21 .
　図６は、冷却運転時および除霜運転時の送風機２２の電流値の一例を示す図である。
　図６において、横軸は時刻ｔを示し、縦軸は、冷凍システム１００において、除霜運転の時間をＴａ、冷却運転の時間をＴｂで行った場合の送風機２２の電流値を示す。 FIG. 6 is a diagram showing an example of current values of the blower 22 during cooling operation and defrosting operation.
In FIG. 6, the horizontal axis indicates the time t, and 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 .
　冷却運転によって、室内熱交換器２１の着霜が進行するので、送風機２２の電流値が増加する。 Due to the cooling operation, frost formation on the indoor heat exchanger 21 progresses, so the current value of the blower 22 increases.
　冷却運転の時間Ｔｂが短い場合には、冷却運転時間が短くなるので、庫内が目標温度に到達しない場合がある。 If 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.
　冷却運転の時間Ｔｂが長い場合には、冷却運転時間が長くなるので、室内熱交換器２１の着霜量が過大になる。すなわち、冷却運転の時間Ｔｂが長い場合には、着霜によって室内熱交換器２１の伝熱性能が低下し、冷却が十分にできないことがある。 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.
　以上のような冷却能力の低下を防ぐために、室内熱交換器２１の除霜開始タイミングの最適化を行う。 The defrosting start timing of the indoor heat exchanger 21 is optimized in order to prevent the decrease in cooling capacity as described above.
　制御装置３は、現在の時刻が定められた時間帯に含まれる場合には、第１の除霜タイミング決定方法を用いて、除霜運転と冷却運転とを切り替える。制御装置３は、第１の除霜タイミング決定方法では、ＥＴ（Exit　Temperature）シフト制御を用いて、除霜開始タイミングを決定し、そのときの送風機２２の電流値を除霜開始閾値ＴＨｓとして記録する。制御装置３は、現在の時刻が定められた時間帯に含まれる場合には、ＥＴシフト制御を用いて、除霜終了タイミングを決定し、そのときの送風機の電流値を除霜終了閾値ＴＨｅとして記録する。 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. In the first defrost timing determination method, 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. When the current time is included in the predetermined time period, 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.
　制御装置３は、現在の時刻が定められた時間帯に含まれない場合には、第２の除霜タイミング決定方法を用いて、除霜運転と冷却運転とを切り替える。制御装置３は、第２の除霜タイミング決定方法では、ＥＴシフト制御によって得られた除霜開始閾値ＴＨｓおよび除霜終了閾値ＴＨｅを用いて、除霜運転と冷却運転とを切り替える。 When the current time is not included in the specified time period, the control device 3 switches between the defrosting operation and the cooling operation using the second defrosting timing determination method. In 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.
　ここで、定められた時間帯とは、夜間などの人の出入りが少ない時間帯である。ＥＴシフト制御では、制御装置３は、蒸発器である室内熱交換器２１における空気の吹出温度と室内熱交換器２１における冷媒の蒸発温度ＥＴとの温度差ΔＴ（＝ＲＴ－ＥＴ）が閾値ＴＨ１以上であると判断した場合に、室内熱交換器２１が着霜したと判断する。このように判断できる理由は、以下である。蒸発器の着霜が進行すると、熱伝達率が低下して冷媒が蒸発器の出口までに蒸発しなくなる。その結果、冷媒の蒸発温度ＥＴが低下するので、温度差ΔＴが大きくなる。このときの送風機の電流値を、現在の時刻が定められた時間帯に含まれない場合における除霜開始閾値とすることができる。 Here, the set time period is a time period when there are few people coming and going, such as at night. In the ET shift control, the control device 3 sets the temperature difference ΔT (=RT-ET) between the blowout temperature of the air in the indoor heat exchanger 21, which is an evaporator, and the evaporation temperature ET of the refrigerant in the indoor heat exchanger 21 to the threshold value TH1. When it is determined that the above is the case, it is determined that the indoor heat exchanger 21 is frosted. The reason why this determination can be made is as follows. As frost builds up on the evaporator, the heat transfer coefficient decreases and the refrigerant does not evaporate until the outlet of the evaporator. As a result, the evaporation temperature ET of the refrigerant decreases, and the temperature difference ΔT increases. The current value of the blower at this time can be used as the defrosting start threshold when the current time is not included in the determined time period.
　図７は、室内熱交換器２１の近傍に配置されるセンサの例を表わす図である。
　蒸発温度ＥＴの測定方法は、室内熱交換器２１の入口側の温度センサ４１によって測定する方法と、出口側の圧力センサ４３によって検出された圧力を飽和ガス温度に換算して求める方法とがある。 FIG. 7 is a diagram showing an example of sensors arranged near the indoor heat exchanger 21. As shown in FIG.
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. .
　本実施の形態によれば、人の出入りが多い昼間は送風機２２の電流値制御によって、人の出入りが少ない夜間はＥＴシフト制御によって、除霜運転と冷却運転と切り替えることができる。人の出入りが多い昼間など、ＥＴシフト制御では正確なタイミングで除霜運転ができない場合に、ファンモータ電流値制御が可能になるため、常に最適な除霜運転を行うことができる。 According to 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. When 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.
　本実施の形態では、送風機の経年劣化によって、送風機２２の電流値が変化した場合でも、ＥＴシフト制御中に測定された送風機２２の電流値を、送風機の経年劣化に応じた除霜開始閾値および除霜終了閾値に設定することができる。 In the present embodiment, even if the current value of the blower 22 changes due to deterioration over time of the blower, 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.
　図８は、実施の形態１における、除霜開始および除霜終了の判定手順を表わすフローチャートである。図８のフローチャート処理は、冷凍システム１００が稼働中、常に実行される。 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.
　ステップＳ１０１において、制御装置３は、冷凍システム１００の冷却運転を開始させる。 In step S101, the control device 3 starts the cooling operation of the refrigeration system 100.
　ステップＳ１０２において、現在の時刻が定められた時間帯に含まれる場合には、処理がステップＳ１０３に進み、現在の時刻が定められた時間帯に含まれない場合には、処理がステップＳ１０４に進む。 In 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. .
　ステップＳ１０３において、制御装置３は、第１の除霜タイミング決定方法を用いて、除霜運転と冷却運転とを切り替える。 In step S103, the control device 3 switches between the defrosting operation and the cooling operation using the first defrosting timing determination method.
　ステップＳ１０４において、制御装置３は、第２の除霜タイミング決定方法を用いて、除霜運転と冷却運転とを切り替える。 In step S104, the control device 3 switches between the defrosting operation and the cooling operation using the second defrosting timing determination method.
　図９は、図８のステップＳ１０３の処理の詳細を表わすフローチャートである。
　ステップＳ５０２において、制御装置３は、室内熱交換器２１における空気の吹出温度ＲＴおよび室内熱交換器２１における冷媒の蒸発温度ＥＴを取得する。 FIG. 9 is a flow chart showing the details of the processing in step S103 of FIG.
In step S<b>502 , 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 .
　ステップＳ５０３において、室内熱交換器２１における空気の吹出温度ＲＴと、室内熱交換器２１における冷媒の蒸発温度ＥＴとの温度差ΔＴ（＝ＲＴ－ＥＴ）が閾値ＴＨ１以上のときには、処理がステップＳ５０５に進む。温度差ΔＴが閾値ＴＨ１未満のときには、処理がステップS４０２に戻る。ＴＨ１は、たとえば、５℃である。 In step S503, when the temperature difference ΔT (=RT-ET) between 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 is equal to or greater than the threshold TH1, the process proceeds to step S505. proceed to When the temperature difference ΔT is less than the threshold TH1, the process returns to step S402. TH1 is, for example, 5°C.
　ステップＳ５０４において、制御装置３は、冷凍システム１００の冷却運転を終了し、除霜運転を開始させるとともに、送風機２２の電流値Ｉｓを取得する。 In 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.
　ステップＳ５０５において、取得した送風機２２の電流値Ｉｓを除霜開始閾値ＴＨｓとして記録する。 In step S505, the acquired current value Is of the blower 22 is recorded as the defrosting start threshold THs.
　ステップＳ５０６において、制御装置３は、室内熱交換器２１における空気の吹出温度ＲＴおよび室内熱交換器２１における冷媒の蒸発温度ＥＴを取得する。 In 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.
　ステップＳ５０７において、室内熱交換器２１における空気の吹出温度ＲＴと室内熱交換器２１における冷媒の蒸発温度ＥＴとの温度差ΔＴ（＝ＲＴ－ＥＴ）が閾値ＴＨ２未満のときには、処理がステップＳ５０９に進む。温度差ΔＴが閾値ＴＨ２以上のときには、処理がステップＳ５０６に戻る。 In step S507, when the temperature difference ΔT (=RT-ET) between the air outlet temperature RT in the indoor heat exchanger 21 and the refrigerant evaporation temperature ET in the indoor heat exchanger 21 is less than the threshold TH2, the process proceeds to step S509. move on. When the temperature difference ΔT is equal to or greater than the threshold TH2, the process returns to step S506.
　ステップＳ５０８において、制御装置３は、冷凍システム１００の除霜運転を終了し、冷却運転を開始させるとともに、送風機２２の電流値Ｉｓを取得する。 In 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.
　ステップＳ５０９において、取得した送風機２２の電流値を除霜終了閾値ＴＨｅとして記録する。 In step S509, the acquired current value of the blower 22 is recorded as the defrosting end threshold THe.
　図１０は、実施の形態１における、図８のステップＳ１０４の処理の詳細を表わすフローチャートである。図１１は、実施の形態１における第２の除霜タイミング決定方法による除霜開始タイミングおよび除霜終了タイミングを表わす図である。 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.
　ステップＳ１において、制御装置３は、送風機２２の電流値Ｉｓが除霜開始閾値ＴＨｓを超えているか否かを判定する。送風機２２の電流値Ｉｓが除霜開始閾値ＴＨｓを超えている場合に、処理がステップＳ２に進む。送風機２２の電流値Ｉｓが除霜開始閾値ＴＨｓを超えていない場合に、制御装置３は、冷凍システム１００の冷却運転を継続させる。 In 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 .
　ステップＳ２において、制御装置３は、冷凍システム１００の冷却運転を終了させ、冷凍システム１００の除霜運転を開始させる。 In 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.
　ステップＳ３において、除霜運転開始から一定時間Δｔが経過した場合に、処理がステップＳ４に進む。除霜運転開始から一定時間Δｔが経過していない場合に、制御装置３は、冷凍システム１００の除霜運転を継続させる。 In step S3, when a certain period of time Δt 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 Δt has not elapsed since the defrosting operation was started.
　ステップＳ４において、制御装置３は、冷凍システム１００の除霜運転を終了させ、冷凍システム１００の冷却運転を開始させる。 In 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.
　特許文献１では、温度効率の閾値は、冷凍機の種類に応じて予め設定される。冷凍庫内には、冷却対象物が置かれ、作業者が出入りすることが想定される。よって、冷凍機の種類が同じでも、実使用環境は、冷凍庫ごとに相違する。 In Patent Document 1, 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.
　本実施の形態によれば、送風機の電流値に基づく除霜運転と冷却運転の切替タイミングを定める除霜開始閾値および除霜終了閾値は、ＥＴシフト制御に基づく除霜運転と冷却運転の切替タイミングにおける送風機の電流値を用いる。これによって、実使用環境に応じて、除霜運転のタイミングを適切に設定することができる。 According to the present embodiment, 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.
　実施の形態２．
　図１２は、実施の形態２における、図８のステップＳ１０４の処理の詳細を表わすフローチャートである。図１３は、実施の形態２における第２の除霜タイミング決定方法による除霜開始タイミングおよび除霜終了タイミングを表わす図である。 Embodiment 2.
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.
　ステップＳ１１において、制御装置３は、送風機２２の電流値Ｉｓが除霜開始閾値ＴＨｓを超えているか否かを判定する。送風機２２の電流値Ｉｓが除霜開始閾値ＴＨｓを超えている場合に、処理がステップＳ１２に進む。送風機２２の電流値Ｉｓが除霜開始閾値ＴＨｓを超えていない場合に、制御装置３は、冷凍システム１００の冷却運転を継続させる。 In 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 .
　ステップＳ１２において、制御装置３は、冷凍システム１００の冷却運転を終了させ、冷凍システム１００の除霜運転を開始させる。制御装置３は、送風機２２を回転させたまま除霜するオフサイクルデフロストを実行させる。 In 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.
　ステップＳ１３において、制御装置３は、送風機２２の電流値Ｉｓが除霜終了閾値ＴＨｅ未満であるか否かを判定する。送風機２２の電流値Ｉｓが除霜終了閾値ＴＨｅ未満の場合に、処理がステップＳ１４に進む。送風機２２の電流値Ｉｓが除霜終了閾値ＴＨｅ未満でない場合に、制御装置３は、冷凍システム１００の除霜運転を継続させる。たとえば、除霜終了閾値ＴＨｅは、試運転時に、室内熱交換器２１の除霜の進行具合を目視によって確認することによって、設定することができる。あるいは、試運転時に除霜終了閾値ＴＨｅを変化させながら冷凍システム１００を運転させて、効率が最大となるときの除霜終了閾値ＴＨｅを実運転で使用することとしてもよい。 In 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. When the current value Is of the blower 22 is less than the defrosting end threshold value THe, the process proceeds to step S14. When the current value Is of the blower 22 is not less than the defrosting end threshold THe, the control device 3 continues the defrosting operation of the refrigeration system 100 . For example, the defrosting end threshold THe can be set by visually confirming the progress of defrosting of the indoor heat exchanger 21 during trial operation. Alternatively, 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.
　ステップＳ１４において、制御装置３は、冷凍システム１００の除霜運転を終了させ、冷凍システム１００の冷却運転を開始させる。 In 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.
　本実施の形態によれば、除霜開始閾値および除霜終了閾値を適切に設定すれば、初期の状態に近い状態まで冷凍システムの冷却能力を確実にもどすことができる。 According to the present embodiment, by appropriately setting 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.
　実施の形態３．
　図１４は、実施の形態３における、図８のステップＳ１０４の処理の詳細を表わすフローチャートである。図１５は、実施の形態３における第２の除霜タイミング決定方法による除霜開始タイミングおよび除霜終了タイミングを表わす図である。 Embodiment 3.
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.
　ステップＳ２１において、制御装置３は、送風機２２の電流値Ｉｓが除霜開始閾値ＴＨｓを超えているか否かを判定する。送風機２２の電流値Ｉｓが除霜開始閾値ＴＨｓを超えている場合に、処理がステップＳ２２に進む。送風機２２の電流値Ｉｓが除霜開始閾値ＴＨｓを超えていない場合に、制御装置３は、冷凍システム１００の冷却運転を継続させる。 In 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 .
　ステップＳ２２において、制御装置３は、冷凍システム１００の冷却運転を終了させ、冷凍システム１００の除霜運転を開始させるとともに、送風機２２の回転を停止させる。 In 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.
　ステップＳ２３において、一定時間Δｔが経過した場合に、処理がステップＳ４に進む。一定時間Δｔが経過していない場合に、制御装置３は、冷凍システム１００の除霜運転を継続させる。 In step S23, when the fixed time Δt has passed, the process proceeds to step S4. If the fixed time Δt has not passed, the control device 3 continues the defrosting operation of the refrigeration system 100 .
　ステップＳ２４において、制御装置３は、送風機２２の回転を開始させる。
　ステップＳ２５において、制御装置３は、送風機２２の電流値Ｉｓが除霜終了閾値ＴＨｅ未満であるか否かを判定する。送風機２２の電流値Ｉｓが除霜終了閾値ＴＨｅ未満の場合に、処理がステップＳ２６に進む。送風機２２の電流値Ｉｓが除霜終了閾値ＴＨｅ未満でない場合に、処理がステップＳ２７に進む。 In step S<b>24 , the control device 3 starts rotating the blower 22 .
In 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.
　ステップＳ２７において、制御装置３は、送風機２２の回転を停止させる。その後、処理がステップＳ２３に戻る。 At step S27, the control device 3 stops the rotation of the blower 22. After that, the process returns to step S23.
　ステップＳ２６において、制御装置３は、冷凍システム１００の除霜運転を終了させ、送風機２２の回転を停止させ、冷凍システム１００の冷却運転を開始させる。 In 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.
　実施の形態４．
　図１６は、実施の形態４に係る冷凍システム２００における冷媒回路の構成の一例を示す概略図である。冷凍システム２００は、室外機２０１、室内機２０２、および制御装置３を備える。 Embodiment 4.
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. As shown in FIG. A refrigeration system 200 includes an outdoor unit 201 , an indoor unit 202 and a control device 3 .
　室外機２０１は、室外機１と同様に、圧縮機１１、室外熱交換器１２、膨張弁１３、凝縮温度センサ１４、蒸発温度センサ１５、ガス冷媒温度センサ１６および室外機制御部１０を備える。室外機２０１は、さらに、バイパス回路１７およびバイパス弁１８を備える。 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 .
　バイパス回路１７は、冷媒配管５における圧縮機１１の吐出側から分岐し、膨張弁１３と室内熱交換器２１との間の冷媒配管５に接続されている。バイパス回路１７は、圧縮機１１から吐出された冷媒の一部が室内熱交換器２１に流入するように設けられている。バイパス弁１８は、バイパス回路１７に設けられている。バイパス弁１８の開閉は、室外機制御部１０を介して制御装置３によって制御され、開閉によってバイパス回路１７を流れる冷媒の流通または遮断を行う。 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. FIG.
　室内機２０２は、室内機２と同様に、室内熱交換器２１、送風機２２および室内機制御部２０を備える。室内機２０２は、室内機２と異なり、除霜部２３が設けられていない。 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 .
　制御装置３は、除霜運転の際に、バイパス弁１８を開状態とする。これにより、圧縮機１１から吐出された高温高圧のガス冷媒の一部がバイパス弁１８を流通し、室内機２０２の室内熱交換器２１に流入する。室内熱交換器２１に高温のガス冷媒が流入することにより、室内熱交換器２１に付着した霜は、冷媒の熱によって溶けて除去される。 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.
　このように、本実施の形態では、除霜部２３に代えて、バイパス回路１７およびバイパス弁１８が設けられることにより、室内熱交換器２１の除霜を行うことが出来る。なお、この例では、除霜部２３が除かれた構成となっているが、これに限られず、除霜部２３が併用されても良い。 Thus, in the present embodiment, 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 . In this example, the defrosting unit 23 is removed, but the configuration is not limited to this, and the defrosting unit 23 may be used together.
　以上のように、本実施の形態の冷凍システム２００において、バイパス回路１７およびバイパス弁１８が除霜部２３として用いられる。これにより、高温の冷媒が室内熱交換器２１に流入するため、室内熱交換器２１に付着した霜を除去することができる。 As described above, the bypass circuit 17 and the bypass valve 18 are used as the defrosting section 23 in the refrigeration system 200 of the present embodiment. As a result, the high-temperature refrigerant flows into the indoor heat exchanger 21, so frost adhering to the indoor heat exchanger 21 can be removed.
　今回開示された実施の形態はすべての点で例示であって制限的なものではないと考えられるべきである。本開示の範囲は上記した説明ではなくて請求の範囲によって示され、請求の範囲と均等の意味及び範囲内でのすべての変更が含まれることが意図される。 The embodiments disclosed this time should be considered illustrative in all respects and not restrictive. The scope of the present disclosure is indicated by the scope of claims rather than the above description, and is intended to include all changes within the meaning and scope of equivalence to the scope of claims.
　１，２０１　室外機、２，２０２　室内機、２１　室内熱交換器、３　制御装置、４　空間温度センサ、５　冷媒配管、１０　室外機制御部、１１　圧縮機、１２　室外熱交換器、１３　膨張弁、１４　凝縮温度センサ、１５　蒸発温度センサ、１６　ガス冷媒温度センサ、１７　バイパス回路、１８　バイパス弁、２０　室内機制御部、２２　送風機、２３　除霜部、３１　処理回路、３２　メモリ、３３　入出力部、４１　温度センサ、４３　圧力センサ、１００，２００　冷凍システム。 1, 201 outdoor unit, 2, 202 indoor unit, 21 indoor heat exchanger, 3 control device, 4 space temperature sensor, 5 refrigerant pipe, 10 outdoor unit control unit, 11 compressor, 12 outdoor heat exchanger, 13 expansion valve , 14 condensation temperature sensor, 15 evaporation temperature sensor, 16 gas refrigerant temperature sensor, 17 bypass circuit, 18 bypass valve, 20 indoor unit control section, 22 blower, 23 defrosting section, 31 processing circuit, 32 memory, 33 input/output section , 41 temperature sensor, 43 pressure sensor, 100, 200 refrigeration system.

Claims (10)

  1. 　環状に接続された圧縮機、室外熱交換器、膨張弁および室内熱交換器と、
    　前記室内熱交換器に付着した霜を除去する除霜部と、
    　前記室内熱交換器に空気を送る送風機と、
    　対象空間を冷却する冷却運転と、前記除霜部を制御して前記室内熱交換器に付着した霜を除去する除霜運転とを切り替える制御装置と、備え、
    　前記制御装置は、前記送風機の電流値に基づいて、前記除霜運転を開始する、冷凍システム。     a compressor, an outdoor heat exchanger, an expansion valve and an indoor heat exchanger connected in a ring;
    a defrosting section for removing frost adhering to the indoor heat exchanger;
    a blower that sends air to the indoor heat exchanger;
    A control device that switches between a cooling operation for cooling the target space and a defrosting operation for controlling the defrosting unit to remove frost adhered to the indoor heat exchanger,
    The refrigeration system, wherein the control device starts the defrosting operation based on a current value of the blower.
  2. 　前記制御装置は、現在時刻が予め定められた時間帯に含まれるときには、前記冷却運転中に、前記室内熱交換器における空気の吹出温度と、前記室内熱交換器における冷媒の蒸発温度とに基づき、前記除霜運転を開始するとともに、前記送風機の電流値を測定して、前記測定した電流値を除霜開始閾値に設定し、
    　前記制御装置は、現在時刻が予め定められた時間帯に含まれないときには、前記冷却運転中に、前記送風機の電流値が前記除霜開始閾値を超えたときに、前記除霜運転を開始する、請求項１記載の冷凍システム。     When the current time is included in a predetermined time period, the control device performs the cooling operation based on the blowout temperature of the air in the indoor heat exchanger and the evaporation temperature of the refrigerant in the indoor heat exchanger. , while starting the defrosting operation, measuring the current value of the blower and setting the measured current value as a defrosting start threshold;
    The control device starts the defrosting operation when the current value of the blower exceeds the defrosting start threshold value during the cooling operation when the current time is not included in the predetermined time period. A refrigeration system according to claim 1.
  3. 　前記制御装置は、現在時刻が前記予め定められた時間帯に含まれないときには、前記除霜運転開始から一定時間経過後に、前記除霜運転を終了する、請求項２記載の冷凍システム。 3. The refrigeration system according to claim 2, wherein when the current time is not included in the predetermined time period, the control device ends the defrosting operation after a certain period of time has passed since the defrosting operation started.
  4. 　前記制御装置は、現在時刻が前記予め定められた時間帯に含まれるときには、前記除霜運転中に、前記室内熱交換器における空気の吹出温度と、前記室内熱交換器における冷媒の蒸発温度とに基づき、前記冷却運転を開始するとともに、前記送風機の電流値を測定して、前記測定した電流値を除霜終了閾値に設定する、請求項２または３記載の冷凍システム。 When the current time is included in the predetermined time period, the control device controls the blowing temperature of the air in the indoor heat exchanger and the evaporation temperature of the refrigerant in the indoor heat exchanger during the defrosting operation. 4. The refrigeration system according to claim 2 or 3, wherein the cooling operation is started based on, the current value of the blower is measured, and the measured current value is set as the defrosting end threshold.
  5. 　前記制御装置は、現在時刻が前記予め定められた時間帯に含まれないときには、前記除霜運転中に、前記送風機を動作させ、前記除霜運転中の前記送風機の電流値が前記除霜終了閾値未満のときに、前記除霜運転を終了する、請求項４記載の冷凍システム。 When the current time is not included in the predetermined time period, the control device operates the blower during the defrosting operation so that the current value of the blower during the defrosting operation reaches the end of defrosting. 5. The refrigeration system according to claim 4, wherein said defrosting operation is terminated when the temperature is less than a threshold.
  6. 　前記制御装置は、現在時刻が前記予め定められた時間帯に含まれないときには、前記除霜運転を開始するとともに、前記送風機を停止させ、前記除霜運転開始から一定時間経過後に前記送風機を動作させ、前記送風機の電流値を測定し、前記除霜終了閾値以上のときは、除霜を再開し、前記送風機の電流値が前記除霜終了閾値未満のときに、前記除霜運転を終了する、請求項４記載の冷凍システム。 When the current time is not included in the predetermined time period, the control device starts the defrosting operation, stops the blower, and operates the blower after a predetermined time has elapsed from the start of the defrosting operation. and measures the current value of the blower, restarts defrosting when the current value is equal to or greater than the defrosting end threshold value, and terminates the defrosting operation when the current value of the blower is less than the defrosting end threshold value. 5. The refrigeration system of claim 4.
  7. 　前記除霜部は、ヒータの熱によって前記室内熱交換器に付着した前記霜を除去する、請求項１～６のいずれか１項に記載の冷凍システム。 The refrigeration system according to any one of claims 1 to 6, wherein the defrosting section removes the frost adhering to the indoor heat exchanger with heat from a heater.
  8. 　前記除霜部は、前記室内熱交換器に散水し、水の熱によって前記室内熱交換器に付着した前記霜を除去する、請求項１～６のいずれか１項に記載の冷凍システム。 The refrigeration system according to any one of claims 1 to 6, wherein the defrosting unit sprays water on the indoor heat exchangers to remove the frost adhering to the indoor heat exchangers with the heat of water.
  9. 　前記除霜部は、前記送風機の風によって前記室内熱交換器に付着した前記霜を除去する、請求項１～６のいずれか１項に記載の冷凍システム。 The refrigeration system according to any one of claims 1 to 6, wherein the defrosting section removes the frost adhering to the indoor heat exchanger with the wind of the blower.
  10. 　前記除霜部は、
    　前記圧縮機の吐出側から分岐し、前記膨張弁と前記室内熱交換器との間に接続され、前記圧縮機から吐出された冷媒の一部を前記室内熱交換器に流入させるバイパス回路と、
    　前記バイパス回路に設けられ、前記バイパス回路を流れる前記冷媒の流通及び遮断を行うバイパス弁と、を有する、請求項１～６のいずれか１項に記載の冷凍システム。     The defrosting unit is
    a bypass circuit that branches from the discharge side of the compressor, is connected between the expansion valve and the indoor heat exchanger, and causes part of the refrigerant discharged from the compressor to flow into the indoor heat exchanger;
    7. The refrigeration system according to any one of claims 1 to 6, further comprising a bypass valve provided in said bypass circuit for circulating and blocking said refrigerant flowing through said bypass circuit.
PCT/JP2021/002785 2021-01-27 2021-01-27 Refrigeration system WO2022162776A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007225158A (en) * 2006-02-21 2007-09-06 Mitsubishi Electric Corp Defrosting operation control device and method
JP2008232617A (en) * 2008-04-26 2008-10-02 Mitsubishi Electric Corp Air conditioner
JP2012220030A (en) * 2011-04-04 2012-11-12 Toyo Eng Works Ltd Defrosting device of carbon dioxide circulation and cooling system
JP2018189340A (en) * 2017-05-11 2018-11-29 ホシザキ株式会社 Cooling storage box

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007225158A (en) * 2006-02-21 2007-09-06 Mitsubishi Electric Corp Defrosting operation control device and method
JP2008232617A (en) * 2008-04-26 2008-10-02 Mitsubishi Electric Corp Air conditioner
JP2012220030A (en) * 2011-04-04 2012-11-12 Toyo Eng Works Ltd Defrosting device of carbon dioxide circulation and cooling system
JP2018189340A (en) * 2017-05-11 2018-11-29 ホシザキ株式会社 Cooling storage box

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