WO2022163793A1 - 冷凍装置、冷凍装置の制御方法及び温度制御システム - Google Patents
冷凍装置、冷凍装置の制御方法及び温度制御システム Download PDFInfo
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- WO2022163793A1 WO2022163793A1 PCT/JP2022/003223 JP2022003223W WO2022163793A1 WO 2022163793 A1 WO2022163793 A1 WO 2022163793A1 JP 2022003223 W JP2022003223 W JP 2022003223W WO 2022163793 A1 WO2022163793 A1 WO 2022163793A1
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- WIPO (PCT)
- Prior art keywords
- compressor
- refrigerant
- temperature
- liquid bypass
- evaporator
- Prior art date
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- 238000005057 refrigeration Methods 0.000 title claims abstract description 63
- 238000000034 method Methods 0.000 title claims description 15
- 239000007788 liquid Substances 0.000 claims abstract description 130
- 239000003507 refrigerant Substances 0.000 claims abstract description 125
- 238000001704 evaporation Methods 0.000 claims abstract description 123
- 230000008020 evaporation Effects 0.000 claims abstract description 61
- 238000011144 upstream manufacturing Methods 0.000 claims abstract description 44
- 239000012530 fluid Substances 0.000 claims description 121
- 230000007704 transition Effects 0.000 claims description 17
- 238000010438 heat treatment Methods 0.000 description 35
- 230000008569 process Effects 0.000 description 5
- 238000001816 cooling Methods 0.000 description 4
- 239000000498 cooling water Substances 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 230000008859 change Effects 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 239000012267 brine Substances 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 239000002826 coolant Substances 0.000 description 2
- 230000007812 deficiency Effects 0.000 description 2
- 230000004043 responsiveness Effects 0.000 description 2
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 2
- 238000001514 detection method Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B1/00—Compression machines, plants or systems with non-reversible cycle
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B13/00—Compression machines, plants or systems, with reversible cycle
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B25/00—Machines, plants or systems, using a combination of modes of operation covered by two or more of the groups F25B1/00 - F25B23/00
- F25B25/005—Machines, plants or systems, using a combination of modes of operation covered by two or more of the groups F25B1/00 - F25B23/00 using primary and secondary systems
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B41/00—Fluid-circulation arrangements
- F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B49/00—Arrangement or mounting of control or safety devices
- F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B49/00—Arrangement or mounting of control or safety devices
- F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
- F25B49/022—Compressor control arrangements
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
- F25B2400/04—Refrigeration circuit bypassing means
- F25B2400/0403—Refrigeration circuit bypassing means for the condenser
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
- F25B2400/04—Refrigeration circuit bypassing means
- F25B2400/0409—Refrigeration circuit bypassing means for the evaporator
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2600/00—Control issues
- F25B2600/02—Compressor control
- F25B2600/025—Compressor control by controlling speed
- F25B2600/0253—Compressor control by controlling speed with variable speed
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2600/00—Control issues
- F25B2600/25—Control of valves
- F25B2600/2501—Bypass valves
Definitions
- the present invention relates to a refrigerating device having a compressor, a condenser, an expansion valve, and an evaporator, a refrigerating device control method, and a temperature control system including the refrigerating device.
- Equipped with a refrigeration system having a compressor, a condenser, an expansion valve and an evaporator, and a fluid circulation system that circulates fluid such as water and brine the temperature at which the fluid circulated by the fluid circulation system is cooled by the evaporator of the refrigeration system Control systems are known (eg JP2014-145565A).
- the temperature control system as described above includes a refrigeration device and a fluid circulation device, it may be relatively large.
- the refrigerating apparatus is provided with an accumulator for suppressing liquid backflow, but the accumulator is relatively large in size, which contributes to an increase in the size of the entire system. For example, if liquid backflow can be suppressed without using such an accumulator, it will be advantageous in terms of compactness.
- the refrigeration system When compensating for the decrease in the amount of refrigerant flowing to the evaporator side in this way by the amount of refrigerant discharged from the compressor, the refrigeration system is normally provided with a sufficient amount of surplus in order to achieve both an appropriate bypass and refrigerating capacity. The reserved amount of refrigerant is charged.
- the use of the surplus refrigerant can also contribute to an increase in the size of the entire system. Also, it is desirable to avoid using many refrigerants in consideration of the environmental load.
- the liquid bypass circuit since the liquid bypass circuit sends refrigerant in a gas-liquid mixture state to the upstream side of the compressor, the risk of liquid backflow can be increased. Therefore, the liquid bypass circuit is often used together with the accumulator. However, in this case, the entire system may become large.
- the present invention has been made in consideration of the above circumstances, and even when the capacity of the accumulator is suppressed or when the accumulator is not used, it is possible to suitably suppress the liquid backflow of the refrigerant in the refrigeration system, and the refrigerant to be used
- a refrigerating device a refrigerating device control method, and a temperature control system capable of appropriately suppressing an excessive rise in the temperature of refrigerant sucked into a compressor while suppressing the amount of for the purpose.
- a refrigeration system includes a refrigeration circuit in which a compressor, a condenser, an expansion valve, and an evaporator are connected by piping in that order so as to circulate a refrigerant; and the condenser in the refrigeration circuit.
- a liquid bypass channel branched from a portion downstream of the expansion valve and upstream of the expansion valve and connected to a portion downstream of the evaporator and upstream of the compressor; a liquid bypass circuit having a liquid bypass control valve that controls the flow of the refrigerant in the liquid bypass flow path; and a control device that controls the rotation speed of the liquid bypass control valve and the compressor,
- the control device opens the liquid bypass control valve when the discharge temperature of the refrigerant discharged from the compressor and before flowing into the condenser exceeds a threshold value, and when the discharge temperature is equal to or less than the threshold value,
- the liquid bypass control valve is closed, the liquid flows through a portion of the refrigeration circuit downstream of the evaporator and upstream of the compressor, which is downstream of the connecting position of the downstream end of the liquid bypass flow path.
- the rotation speed of the compressor is adjusted so that the evaporating pressure of the refrigerant reaches a preset target evaporating pressure.
- a method for controlling a refrigeration system includes a refrigeration circuit in which a compressor, a condenser, an expansion valve, and an evaporator are connected by piping in that order so as to circulate refrigerant; a liquid bypass flow path branched from a portion downstream of the condenser and upstream of the expansion valve and connected to a portion downstream of the evaporator and upstream of the compressor; and the liquid bypass.
- a control method for a refrigeration system comprising: a liquid bypass circuit having a liquid bypass control valve that is provided in a flow path and controls the flow of the refrigerant in the liquid bypass flow path, a step of operating the refrigeration device;
- the liquid bypass control valve When the discharge temperature of the refrigerant discharged from the compressor and before flowing into the condenser exceeds a threshold value, the liquid bypass control valve is opened, and when the discharge temperature is equal to or less than the threshold value, the liquid bypass control is performed.
- a valve is closed to evaporate the refrigerant flowing through a portion downstream of the evaporator and upstream of the compressor in the refrigeration circuit and downstream of the connection position of the downstream end of the liquid bypass flow path. and adjusting the rotation speed of the compressor so that the pressure reaches a preset target evaporation pressure.
- a temperature control system exchanges heat between the refrigerating device and the fluid in the evaporator, then sends the fluid to a temperature controlled object, and transfers the fluid that has passed through the temperature controlled object to the evaporator. and a fluid circulating device that causes heat to be exchanged again with the evaporator, and has a heater at a position downstream of the temperature controlled object and upstream of the evaporator.
- liquid backflow of the refrigerant in the refrigeration system can be suitably suppressed, and the amount of refrigerant to be used can be suppressed while the compressor An excessive rise in the temperature of the refrigerant sucked into the cooling medium can be suitably suppressed, and an appropriate cooling operation can be performed.
- FIG. 1 is a diagram showing a schematic configuration of a temperature control system according to an embodiment of the invention
- FIG. FIG. 2 is a block diagram showing a functional configuration of a control device that constitutes the temperature control system shown in FIG. 1
- FIG. 2 is an example of the operation of a control device that constitutes the temperature control system shown in FIG. 1, and is a flowchart illustrating an example of the operation when controlling a liquid bypass control valve of a refrigeration system
- 2 is an example of the operation of a control device that constitutes the temperature control system shown in FIG. 1, and is a flowchart illustrating an example of the operation when controlling the rotation speed of a compressor of a refrigeration system and a gas bypass control valve.
- 2 is an example of the operation of a control device that constitutes the temperature control system shown in FIG. 1, and is a flowchart for explaining an example of the operation when controlling the flow circulation device.
- FIG. 1 is a schematic diagram of a temperature control system 1 according to one embodiment of the present invention.
- the temperature control system 1 shown in FIG. 1 includes a refrigerating device 10 and a fluid circulating device 20 , and the refrigerating device 10 and the fluid circulating device 20 are controlled by a control device 30 .
- the refrigerating device 10 controls the temperature of the fluid circulated by the fluid circulating device 20 with a refrigerant.
- the fluid circulating device 20 supplies the temperature-controlled object T with the fluid whose temperature has been controlled by the refrigerating device 10 .
- the fluid circulation device 20 circulates the fluid that has passed through the temperature control target T. Then, the temperature of the fluid returned from the temperature-controlled target T is again controlled by the refrigerating device 10 .
- the fluid circulated by the fluid circulation device 20 is, for example, brine, but other fluids such as water may also be used.
- control device 30 sets the temperature of the fluid to be supplied to the temperature controlled object T according to the user's operation, and controls each part of the refrigeration device 10 and the fluid circulation device 20 so that the temperature of the fluid reaches the set temperature. to control.
- the refrigerating device 10, the fluid circulation device 20, and the control device 30 will be described in detail below.
- the refrigerating apparatus 10 includes a refrigerating circuit 10A configured by connecting a compressor 11, a condenser 12, an expansion valve 13, and an evaporator 14 in this order by a pipe 15 so as to circulate the refrigerant, and a refrigerating circuit 10A. It has a liquid bypass circuit 16 and a gas bypass circuit 17 which are connected, a discharge temperature sensor 18 and an evaporation pressure sensor 19 .
- the compressor 11 compresses the low-temperature, low-pressure gaseous refrigerant flowing out of the evaporator 14 and supplies it to the condenser 12 as a high-temperature, high-pressure gaseous state.
- the condenser 12 cools and condenses the refrigerant compressed by the compressor 11 with cooling water, and supplies the refrigerant to the expansion valve 13 as a high-pressure liquid at a predetermined cooling temperature.
- Cooling Water may be used as the cooling water for the condenser 12, or other refrigerants may be used.
- Reference numeral 5 in the drawing indicates a cooling water pipe that supplies cooling water to the condenser 12 .
- the condenser 12 may be of an air-cooled type.
- the expansion valve 13 expands the refrigerant supplied from the condenser 12 to depressurize it, and supplies it to the evaporator 14 as a low-temperature, low-pressure gas-liquid mixed state.
- the evaporator 14 exchanges heat between the refrigerant supplied from the expansion valve 13 and the fluid in the fluid circulation device 20 .
- the refrigerant that has exchanged heat with the fluid becomes a low-temperature, low-pressure gas state, flows out of the evaporator 14 , and is compressed again by the compressor 11 .
- the liquid bypass circuit 16 branches off from a portion downstream of the condenser 12 and upstream of the expansion valve 13 in the refrigeration circuit 10A, and is connected to a portion downstream of the evaporator 14 and upstream of the compressor 11. It has a liquid bypass channel 16A and a liquid bypass control valve 16B which is provided in the liquid bypass channel 16A and controls the flow of refrigerant in the liquid bypass channel 16A.
- the gas bypass circuit 17 branches from a portion downstream of the compressor 11 and upstream of the condenser 12 in the refrigeration circuit 10A, and is connected to a portion downstream of the expansion valve 13 and upstream of the evaporator 14. It has a gas bypass flow path 17A and a gas bypass control valve 17B provided in the gas bypass flow path 17A for controlling the flow of refrigerant in the gas bypass flow path 17A.
- the discharge temperature sensor 18 detects the temperature of the refrigerant discharged from the compressor 11 and before flowing into the condenser 12 .
- the evaporating pressure sensor 19 is a portion of the refrigeration circuit 10A downstream of the evaporator 14 and upstream of the compressor 11, which is downstream of the connection position of the downstream end of the liquid bypass flow path 16A. The pressure is detected as evaporating pressure.
- Information detected by the discharge temperature sensor 18 and information detected by the evaporation pressure sensor 19 are input to the control device 30 .
- the liquid bypass control valve 16B of the liquid bypass circuit 16 is controlled by the control device 30 according to the discharge temperature detected by the discharge temperature sensor 18, and the gas bypass control valve 17B of the gas bypass circuit 17 is controlled by the evaporation It is controlled by the control device 30 according to the evaporation pressure detected by the pressure sensor 19 .
- the rotation speed of the compressor 11 is also controlled by the controller 30 according to the evaporation pressure detected by the evaporation pressure sensor 19 .
- the refrigerating apparatus 10 in the present embodiment is not provided with an accumulator.
- the refrigerator 10 may be provided with an accumulator.
- the fluid circulation device 20 includes a main flow pipe 21 having a return port 21U and a supply port 21D, and temperature control is performed via flow pipes connected to the return port 21U and the supply port 21D. Connected to target T.
- the fluid circulation device 20 has a main flow pipe 21 connected to the evaporator 14 , and the fluid flowing through the main flow pipe 21 is heat-exchanged by the evaporator 14 and then sent to the temperature control target T.
- the fluid circulating device 20 causes the fluid that has passed through the temperature controlled object T to exchange heat again in the evaporator 14 .
- the fluid circulation device 20 further includes a pump 22, a tank 23 and a heater 24 provided on the main flow pipe 21, and first to third temperature sensors 25-27.
- the pump 22 constitutes a part of the main flow pipe 21 and generates a driving force for circulating the fluid.
- the pump 22 is arranged on the upstream side of the connecting portion of the main flow pipe 21 with the evaporator 14, but its position is not particularly limited.
- the tank 23 and the heater 24 are arranged on the upstream side of the connecting portion of the main flow pipe 21 with the evaporator 14. , it is arranged downstream of the temperature controlled object T and upstream of the evaporator 14 .
- the tank 23 is provided to store a certain amount of fluid and forms part of the main flow pipe 21, and the heater 24 is provided to heat the fluid.
- the heater 24 is arranged inside the tank 23 in this embodiment, the heater 24 may be provided outside the tank 23 .
- the heater 24 is electrically connected to the control device 30 and has its heating capacity controlled by the control device 30 .
- the first temperature sensor 25 detects the temperature of the fluid flowing downstream of the connecting portion of the main flow pipe 21 with the evaporator 14, and the second temperature sensor 26 passes through the temperature control target T. After that, the temperature of the fluid flowing upstream of the heater 24 is detected. Specifically, the second temperature sensor 26 detects the temperature of the fluid that flows upstream of the heater 24 after passing through the temperature controlled object T and before flowing into the tank 23 .
- the third temperature sensor 27 detects the temperature of the fluid that flows downstream of the heater 24 in the fluid circulation device 20 and before passing through the evaporator 14 .
- These first to third temperature sensors 25 to 27 are electrically connected to the control device 30, and temperature information detected by each sensor 25 to 27 is transmitted to the control device 30.
- the control device 30 is a controller that controls the operations of the refrigerating device 10 and the fluid circulating device 20, and may be configured by a computer having a CPU, a ROM, and the like, for example. In this case, various processes are performed according to the programs stored in the ROM. Note that the control device 30 may be configured by other processors or electric circuits (for example, FPGA (Field Programmable Gate Alley), etc.).
- FIG. 2 is a block diagram showing the functional configuration of the control device 30.
- the control device 30 has a fluid circulation device control module 30A and a refrigeration device control module 35 .
- the fluid circulator control module 30A and the refrigerating device control module 35 may be configured, for example, within a single computer, or may be configured within separate computers.
- Fluid circulation device control module First, the fluid circulation device control module 30A will be described in detail.
- the fluid circulation device control module 30A has a temperature setting section 31, a temperature acquisition section 32, a state determination section 33, and a heater control section . Each of these functional units is realized by executing a program, for example.
- the temperature setting unit 31 sets and holds the temperature of the fluid to be supplied to the temperature control target T as a set temperature according to the user's operation. In addition, the temperature setting unit 31 sets and holds the target temperature of the return temperature of the fluid before passing through the evaporator 14, which is the fluid flowing downstream of the heater 24, according to the user's operation. It is.
- the target temperature is set within a temperature range in which the refrigerant exchanging heat with the fluid of the fluid circulation device 20 and flowing out of the evaporator 14 reaches superheated vapor.
- the target temperature is appropriately set according to the refrigerating capacity of the refrigerating device 10, the type of refrigerant, the target evaporation temperature of the refrigerant, which will be described later, and the like. If the return temperature of the fluid that flows downstream of the heater 24 and has not yet passed through the evaporator 14 is equal to or higher than the target temperature, the compressor 11 is cooled while the refrigerant contains a liquid phase. You can avoid the risk of returning to the liquid back.
- the temperature acquisition unit 32 acquires temperature information detected by the first to third temperature sensors 25 to 27.
- the temperature information acquired from the first to third temperature sensors 25 to 27 is received by the state determination unit 33, It is sent to the heater control section 34 and the refrigerator control module 35 side.
- the state determination unit 33 determines the state of the fluid circulation device 20 based on the temperature information detected by the first to third temperature sensors 25-27.
- the state determination unit 33 determines whether the state of the fluid circulating device 20 is no-load operation or no-load operation transition for shifting to this no-load operation based on the temperature information detected by the second temperature sensor 26 . It is determined whether or not the vehicle has been driven. Specifically, based on the temperature information detected by the second temperature sensor 26, the state determination unit 33 determines that the temperature of the fluid flowing upstream of the heater 24 after passing through the temperature control target T is lower than the predetermined temperature. If it has become smaller, it is determined that the state of the fluid circulating device 20 has changed to no-load operation or no-load operation transition operation.
- No-load operation means a state in which the temperature control target T does not exchange heat with the fluid
- no-load operation transition operation is a state in the middle of transition to no-load operation, when the temperature control target T is normal with the fluid. It means a state in which heat is not exchanged more than
- the temperature controlled object T is a device that generates heat
- the temperature-controlled fluid exchanges heat with the temperature controlled object T, and after passing through the temperature controlled object T, heats up.
- the temperature is higher than before replacement.
- the temperature controlled object T which is a device, is stopped and the heat generation gradually decreases, the temperature controlled object T does not exchange heat with the fluid more than in the case of normal operation. , the temperature controlled object T is in a state where it does not exchange heat with the fluid.
- the no-load operation transition operation is a state in which, for example, when the temperature controlled object T, which is a device, is stopped, the temperature controlled object T does not exchange heat with the fluid as much as in the normal case.
- the no-load operation means that, for example, when the temperature controlled object T, which is a device, is stopped, the temperature controlled object T is in a state where it does not substantially exchange heat with the fluid.
- the predetermined temperature which is the criterion for determining whether the no-load operation or the no-load operation transition operation has occurred, is, for example, the temperature equal to or higher than the set temperature of the fluid supplied to the temperature controlled object T. is appropriately selected in relation to
- the state determination unit 33 in the present embodiment determines the fluid flowing downstream of the heater 24 and the fluid before passing through the evaporator 14 based on the temperature information detected by the third temperature sensor 27 . is lower than the target temperature, and if it is lower than the target temperature, a liquid back risk signal is generated. A warning may be issued, for example, when such a liquid bag risk signal is generated.
- the state determination unit 33 also compares the temperature information detected by the first temperature sensor 25 with the set temperature to detect lack of refrigerating capacity.
- the heater control unit 34 operates the heater 24 to circulate the fluid. It is to be heated.
- the heater control unit 34 in the present embodiment operates the heater 24 when the state of the fluid circulation device 20 is the no-load operation or the no-load operation transition operation. After that, the heater control section 34 controls the heating capacity of the heater 24 .
- the controller 30 in the present embodiment causes the heater control unit 34 to first set the heating capacity Q for setting the temperature of the fluid passing through the evaporator 14 to the target temperature Tt. It is calculated from the following formula (1).
- Q m ⁇ Cp ⁇ (Tt ⁇ Ts) (1)
- Ts ° C.
- Ts ° C.
- Tt (° C.) the temperature
- m (kg/s) the weight flow rate of the fluid through which the fluid circulator 20 flows
- Cp (J/kg° C.) be the specific heat of the fluid.
- the set temperature Ts and the target temperature Tt are set by the temperature setting unit 31 .
- the weight flow rate m may be detected by a flow rate sensor or specified from the state of the pump 22 .
- the specific heat Cp of the fluid is stored in the control device 30 in advance.
- the controller 30 controls the heating capacity of the heater 24 based on the heating capacity Q calculated by the formula (1) by the heater control section 34 .
- the heater control unit 34 controls the heating capacity of the heater 24 to be equal to or higher than the heating capacity Q calculated by the formula (1).
- the heating capacity which is such a control target value, may be determined in advance based on the heating capacity Q calculated in advance using formula (1), and may be stored in the control device 30 in advance.
- the heating capacity Q calculated by the formula (1) may exceed the maximum heating capacity of the heater 24.
- controller 30 controls heater 24 to its maximum heating capacity.
- the heater 24 is controlled so that the heating capacity of the heater 24 is greater than or equal to the heating capacity Q calculated by the formula (1). It may be controlled to be the heating capacity Q calculated in (1). Further, when the heating capacity of the heater 24 is controlled to be equal to or higher than the heating capacity Q calculated by Equation (1), it is desirable to set a value not excessively larger than the heating capacity Q (for example, 2Q or less).
- the reason why the heater 24 is operated when the state of the fluid circulation device 20 is no-load operation or no-load operation transition operation is that the fluid passes through the evaporator 14 in a low temperature state and the refrigerant on the side of the refrigerating device 10 evaporates. is insufficient, resulting in liquid backflow.
- the heating capacity of the heater 24 increases, the risk of liquid backflow decreases.
- the heating capacity of the heater 24 becomes excessively large, problems such as seizure of the compressor 11 may occur. Therefore, it is desirable that the heating capacity of the heater 24 is not excessively large.
- the control device 30 controls the flow of the fluid flowing downstream of the heater 24 before passing through the evaporator 14 .
- the heater 24 may be adjusted if the temperature of the fluid does not reach or exceed the target temperature Tt. In other words, after the heating capacity of the heater 24 is controlled, based on the temperature information detected by the third temperature sensor 27, the fluid flowing downstream of the heater 24 and before passing through the evaporator 14 returns.
- the heater 24 may be adjusted when it is determined whether the temperature is less than the target temperature and the liquid back risk signal is generated. At this time, a warning may be issued at the same time as the heater 24 is adjusted.
- the refrigeration device control module 35 includes a fluid temperature information acquisition unit 351, a target value setting unit 352, a discharge temperature acquisition unit 353, an evaporating pressure acquisition unit 354, an expansion valve control unit 355, a compressor control unit 356, It has a liquid bypass control section 357 and a gas bypass control section 358 .
- Each of these functional units is realized by executing a program, for example.
- the fluid temperature information acquisition unit 351 acquires the above-described set temperature set by the temperature setting unit 31 on the fluid circulation device control module 30A side, and the fluid detection temperature detected by the first temperature sensor 25 on the fluid circulation device 20 side. is obtained.
- the fluid temperature information acquisition section 351 transmits the acquired set temperature to the target value setting section 352 and the expansion valve control section 355 , and also transmits the acquired detected temperature to the expansion valve control section 355 .
- the target value setting unit 352 sets the reference rotation speed of the compressor 11 based on the set temperature transmitted from the fluid temperature information acquisition unit 351, sets the target evaporation pressure corresponding to the reference rotation speed, and further is for setting the threshold value of the discharge temperature of the refrigerant discharged from the compressor 11 .
- the set temperature which is the control target value of the temperature of the fluid, can be set to 10°C, 0°C, -10°C, for example.
- the target value setting unit 352 sets, for example, the reference speed of the compressor 11 and the corresponding target evaporating pressure according to such a set temperature. This adjusts the desired refrigeration capacity.
- the reference speed and the target evaporating pressure are set to larger values as the set temperature is lower.
- the threshold value of the ejection temperature is set to a constant value such as 80° C. and recorded in advance in the present embodiment.
- the discharge temperature acquisition unit 353 acquires the temperature of the refrigerant discharged from the compressor 11 and before it flows into the condenser 12 from the discharge temperature sensor 18, and transmits the acquired information regarding the temperature of the refrigerant to the liquid bypass control unit 357. It is something to do.
- the evaporation pressure acquisition unit 354 acquires the evaporation pressure of the refrigerant flowing out of the evaporator 14 from the evaporation pressure sensor 19, and transmits the acquired information about the evaporation pressure to the compressor control unit 356 and the gas bypass control unit 358. It is.
- the expansion valve control unit 355 acquires the set temperature set by the temperature setting unit 31 from the fluid temperature information acquisition unit 351 as described above, and detects the fluid detected by the first temperature sensor 25 on the fluid circulation device 20 side. It is designed to acquire the temperature.
- the expansion valve control section 355 adjusts the degree of opening of the expansion valve 13 according to the difference between the set temperature and the detected temperature so that the detected temperature becomes the set temperature.
- the expansion valve control unit 355 adjusts the opening degree of the expansion valve 13 by PID control in this embodiment.
- the method of controlling the expansion valve 13 by the expansion valve control section 355 is not particularly limited.
- the compressor control unit 356 acquires information on the reference rotation speed of the compressor 11 set by the target value setting unit 352 and the target evaporating pressure corresponding thereto, and determines the evaporating pressure of the refrigerant flowing out of the evaporator 14. Information is acquired from the evaporation pressure acquisition unit 354 as described above. And the compressor control part 356 controls the rotation speed of the compressor 11 based on these information.
- the compressor control unit 356 first controls the rotation speed of the compressor 11 to the reference rotation speed set by the target value setting unit 352 . Then, after the rotation speed of the compressor 11 is controlled to the reference rotation speed (after startup), the compressor control unit 356 constantly monitors the refrigerant evaporation pressure acquired from the evaporation pressure acquisition unit 354, and the evaporation pressure is The rotation speed of the compressor 11 is adjusted when the target evaporation pressure is deviated.
- the compressor control unit 356 increases the rotational speed of the compressor 11 when the refrigerant evaporating pressure exceeds the target evaporating pressure, and increases the rotation speed of the compressor 11 when the refrigerant evaporating pressure falls below the target evaporating pressure.
- the rotation speed of the compressor 11 is controlled so that the rotation speed is lowered and the evaporation pressure of the refrigerant reaches the target evaporation pressure. That is, the control device 30 adjusts the rotational speed of the compressor 11 by means of the compressor control section 356 so that the evaporation pressure of the refrigerant reaches the target evaporation pressure.
- the compressor control unit 356 in the present embodiment adjusts the rotational speed of the compressor 11 by PI control so that the evaporation pressure of the refrigerant reaches the target evaporation pressure. This prevents the loss of control stability due to excessive fluctuations in the rotation speed.
- the control method by the compressor control unit 356 is not particularly limited.
- the compressor control unit 356 reduces the rotation speed of the compressor 11 when the refrigerant evaporation pressure is lower than the target evaporation pressure, but has a lower limit value for the rotation speed. That is, when the rotation speed of the compressor 11 is lowered to the lower limit, even if the evaporation pressure of the refrigerant is lower than the target evaporation pressure, the rotation speed of the compressor 11 is not lowered below the lower limit. .
- the liquid bypass control unit 357 acquires information on the discharge temperature threshold (for example, 80° C.) set by the target value setting unit 352, and the refrigerant discharged from the compressor 11 before flowing into the condenser 12. Temperature information is obtained from the discharge temperature sensor 18 . Then, the liquid bypass control unit 357 opens the liquid bypass control valve 16B when the discharge temperature of the refrigerant based on the information from the discharge temperature sensor 18 exceeds the threshold, and when the discharge temperature of the refrigerant is below the threshold, The liquid bypass control valve 16B is closed.
- the discharge temperature threshold for example, 80° C.
- control device 30 opens the liquid bypass control valve 16B when the discharge temperature of the refrigerant discharged from the compressor 11 and before flowing into the condenser 12 exceeds a threshold value, and when the discharge temperature is equal to or less than the threshold value, The liquid bypass control valve 16B is closed or kept closed.
- the liquid bypass control unit 357 in the present embodiment sets the threshold so that the discharge temperature falls below the threshold according to the difference between the discharge temperature and the threshold. Specifically, the opening is adjusted by PID control. By using PID control in this way, the responsiveness of adjusting the discharge temperature is enhanced, but the control method is not particularly limited.
- the gas bypass control unit 358 acquires information on the evaporation pressure of the refrigerant flowing out of the evaporator 14 from the evaporation pressure acquisition unit 354 as described above, and operates the gas bypass control valve 17B based on the acquired information on the evaporation pressure. It is designed to control.
- the gas bypass control unit 358 in the present embodiment reduces the refrigerant evaporating pressure to the target evaporating pressure or
- the gas bypass control valve 17B is opened so that it becomes more.
- the degree of opening of the gas bypass control valve 17B is adjusted according to the difference between the evaporation pressure of the refrigerant and the target evaporation pressure. More specifically, the degree of opening is adjusted by PID control.
- the control method of the gas bypass control valve 17B is not particularly limited.
- FIG. 3A is a flow chart explaining an example of the operation when controlling the liquid bypass control valve 16B.
- FIG. 3B is a flowchart illustrating an example of the operation when controlling the rotation speed of the compressor 11 and the gas bypass control valve 17B.
- the control device 30 in the present embodiment controls the liquid bypass control valve 16B and controls the rotation speed of the compressor 11 and the gas bypass control valve 17B in parallel. It is supposed to be done in a loop.
- control device 30 first controls the rotation speed of the compressor 11 to the reference rotation speed to start the refrigerating device 10 . After this startup, the control of the liquid bypass control valve 16B shown in FIG. 3A and the rotation speed of the compressor 11 and the gas bypass control valve 17B shown in FIG. 3B start.
- the control device 30 first monitors whether the refrigerant discharge temperature based on information from the discharge temperature sensor 18 exceeds a threshold value.
- step S11 If it is determined in step S11 that the discharge temperature exceeds the threshold value (YES), the controller 30 causes the liquid bypass control section 357 to open the liquid bypass control valve 16B in step S12. At this time, the liquid bypass control unit 357 adjusts the opening degree of the liquid bypass control valve 16B by PID control so that the discharge temperature becomes equal to or less than the threshold according to the difference between the discharge temperature and the threshold.
- step S11 the controller 30 closes the liquid bypass control valve 16B in step S13. At this time, when the liquid bypass control valve 16B is open, the liquid bypass control valve 16B is closed, and when the liquid bypass control valve 16B is closed, the closed state is maintained.
- control device 30 monitors whether or not a command to stop the operation of the refrigerating device 10 has been issued in step S14. Stop driving (end). On the other hand, if no shutdown command has been issued (NO), the process returns to step S11 to monitor the discharge temperature.
- the rotation speed of the compressor 11 is adjusted.
- the rotation speed of the compressor 11 is increased when the refrigerant evaporation pressure exceeds the target evaporation pressure, and the rotation speed of the compressor 11 is increased when the refrigerant evaporation pressure is lower than the target evaporation pressure. RPM is lowered.
- the control device 30 determines whether or not the rotational speed of the compressor 11 is the lower limit value in step S22. If it is not the lower limit value (NO), in step S23, the controller 30 closes the gas bypass control valve 17B. At this time, when the gas bypass control valve 17B is open, the gas bypass control valve 17B is closed, and when the gas bypass control valve 17B is closed, the closed state is maintained.
- step S24 the control device 30 determines whether or not the evaporating pressure of the refrigerant is lower than the target evaporating pressure. . If it is determined in step S24 that the refrigerant evaporation pressure is lower than the target evaporation pressure, the controller 30 controls the gas bypass control valve 17B to open in step S25 so that the evaporation pressure matches the target evaporation pressure. do. This increases the evaporation pressure.
- step S23 if the refrigerant evaporation pressure is not below the target evaporation pressure in step S24, and after the process of step S25, the control device 30 determines in step S26 that a command to stop the operation of the refrigerating device 10 is issued. It is monitored whether or not an operation stop command has occurred, and if an operation stop command has occurred (YES), the operation of the refrigeration system 10 is stopped (end). On the other hand, if no operation stop command has been issued (NO), the process returns to step S21.
- the refrigerating device 10 can avoid a situation in which the discharge temperature of the compressor 11 becomes excessively high while ensuring an appropriate refrigerating capacity in the evaporator 14. Furthermore, the risk of liquid backflow can be suppressed.
- the rotation speed of the compressor 11 is adjusted so as to ensure the refrigerating capacity. Specifically, when the detected evaporating pressure exceeds the target evaporating pressure, it is determined that the refrigerating capacity is insufficient, and the rotation speed is increased. If the detected evaporating pressure is lower than the target evaporating pressure, it is determined that the refrigerating capacity is excessive, and the rotation speed is reduced.
- the control device 30 determines that the proper refrigerating capacity is ensured. In addition, refrigerant with excessively high pressure flows into the compressor 11 and the discharge temperature becomes excessively high, and refrigerant with low pressure flows into the compressor 11 and the compression ratio increases. Excessive high temperature is suppressed.
- the evaporating pressure is lower than the target evaporating pressure, the risk of liquid backflow increases. However, since the evaporating pressure is controlled to the target evaporating pressure by adjusting the rotational speed of the compressor 11, the risk of liquid backflow can be suppressed.
- the rotational speed of the compressor 11 is adjusted so that the evaporating pressure reaches a preset target evaporating pressure.
- liquid backflow is suppressed using the evaporation pressure of the refrigerant after the refrigerant flows from the liquid bypass control valve 16B as an index. Control to the target evaporation pressure is performed. As a result, the reliability of suppressing liquid backflow can be improved.
- the refrigerant flowing through a portion downstream of the evaporator 14 and upstream of the compressor 11 in the refrigeration circuit 10A and upstream of the connection position of the downstream end of the liquid bypass flow path 16A may be adopted in which the rotational speed of the compressor 11 is adjusted so that the evaporating pressure reaches a preset target evaporating pressure.
- the evaporating pressure cannot be properly controlled by the above-described rotation speed control due to, for example, a sudden load change, and the discharge temperature becomes high
- the refrigerant is supplied to the compressor 11 by the liquid bypass control valve 16B.
- the number of times the liquid bypass control valve 16B is operated can be suppressed by controlling the evaporation pressure by controlling the rotation speed. As a result, the risk of liquid bagging can be suppressed.
- control of the liquid bypass control valve 16B and the rotation speed of the compressor 11 and the gas bypass control valve 17B are performed in separate loops. In this case, the responsiveness of each control can be improved. . Alternatively, these controls may be performed in a series of sequences.
- FIG. 4 is a flowchart for explaining an example of the operation of the control device 30. As shown in FIG. An example of the operation of the control device 30 (heater control section 34) will be described below with reference to FIG.
- the operation shown in FIG. 4 starts when the state determination unit 33 determines that the state of the fluid circulation device 20 has changed to no-load operation or no-load operation transition operation.
- the heater control unit 34 first activates the heater 24 in step S101.
- step S102 the heater control unit 34 calculates the heating capacity Q for bringing the temperature of the fluid passing through the evaporator 14 to the target temperature Tt according to the above equation (1).
- step S103 the heater control unit 34 controls the heating capacity of the heater 24 based on the heating capacity Q calculated by Equation (1). Specifically, the heater 24 is controlled such that its heating capacity is equal to or higher than the heating capacity Q. As shown in FIG.
- step S104 the state determination unit 33 monitors whether or not the no-load operation or no-load operation transition operation continues.
- the monitoring is repeated.
- the heater control unit 34 stops the heater 24 in step S105, and the operation ends.
- the state in which the no-load operation or the no-load operation transition operation is exited is based on the temperature information detected by the second temperature sensor 26, after passing through the temperature controlled object T, the flow of the fluid flowing upstream of the heater 24 is It can be determined by detecting that the temperature has reached or exceeded a predetermined temperature.
- the control device 30 in the refrigeration system 10 operates the liquid bypass control valve 16B when the discharge temperature of the refrigerant discharged from the compressor 11 and before flowing into the condenser 12 exceeds the threshold value. Open and close the liquid bypass control valve 16B when the discharge temperature is below the threshold.
- the control device 30 controls the portion of the refrigeration circuit 10A downstream of the evaporator 14 and upstream of the compressor 11, which is downstream of the connection position of the downstream end of the liquid bypass flow path 16A. The rotation speed of the compressor 11 is adjusted so that the evaporating pressure of is equal to the preset target evaporating pressure.
- the control device 30 determines that the proper refrigerating capacity is ensured. In addition, refrigerant with excessively high pressure flows into the compressor 11 and the discharge temperature becomes excessively high, and refrigerant with low pressure flows into the compressor 11 and the compression ratio increases. Excessive high temperature is suppressed.
- the evaporating pressure is lower than the target evaporating pressure, the risk of liquid backflow increases.
- the evaporating pressure is controlled to the target evaporating pressure by adjusting the rotational speed of the compressor 11, the risk of liquid backflow can be suppressed.
- a situation in which the evaporating pressure exceeds the target evaporating pressure can occur, for example, when the load increases.
- a situation in which the evaporating pressure falls below the target evaporating pressure can occur, for example, when the load drops.
- the evaporating pressure cannot be properly controlled by the above-described rotation speed control due to, for example, a sudden load change, and the discharge temperature becomes high
- the refrigerant is supplied to the compressor 11 by the liquid bypass control valve 16B.
- the number of times the liquid bypass control valve 16B is operated can be suppressed by controlling the evaporation pressure by controlling the rotation speed. As a result, the risk of liquid bagging can be suppressed.
- the risk of liquid backflow is suppressed by controlling the evaporation pressure and suppressing the number of times the liquid bypass control valve 16B is actuated, so that the capacity of the accumulator can be suppressed or the accumulator can be omitted. And thereby, the quantity of the refrigerant
- the operation of the liquid bypass control valve 16B is controlled using the discharge temperature of the refrigerant from the compressor 11 as an index.
- the liquid bypass control valve 16B becomes difficult to operate under the influence of the disturbance, and frequent operation is effectively suppressed.
- it is possible to reduce the amount of refrigerant used.
- the suction temperature is likely to change and may include disturbances, so liquid bypass tends to be performed frequently. Therefore, in order to perform proper heat exchange in the evaporator (to ensure refrigerating capacity), a sufficient surplus amount of refrigerant may be secured.
- the configuration of the present embodiment makes it easier to suppress the amount of refrigerant used.
- liquid backflow of the refrigerant in the refrigeration system 10 can be suitably suppressed, and the amount of refrigerant to be used can be suppressed.
- an excessive rise in the temperature of the refrigerant sucked into the compressor 11 can be suitably suppressed, and an appropriate cooling operation can be performed.
- the control device 30 causes the heater control section 34 to operate the heater 24 when the no-load operation or the no-load operation transition operation is determined on the fluid circulation device 20 side.
- the fluid circulated by the fluid circulation device 20 passes through the evaporator 14 in a low temperature state, and the refrigerant on the side of the refrigeration device 10 evaporates insufficiently (that is, the evaporation pressure decreases). can be avoided.
- the temperature control system 1 can be easily made compact.
- the refrigerating apparatus 10 As described above, according to the refrigerating apparatus 10 according to the present embodiment, it is possible to suitably suppress an excessive rise in the temperature of the refrigerant sucked into the compressor 11 while suppressing the amount of refrigerant to be used, and to properly A cooling operation can be performed.
- the rated refrigerating capacity of the refrigerating device 10 is P (Kw)
- the inventor of the present invention has However, we have confirmed that proper operation can be carried out.
- the findings of the present inventor in a general refrigeration system having an accumulator and a receiver tank, when the rated refrigerating capacity is P (Kw), refrigerant of (1.2 ⁇ P) Kg or more is used. .
- the refrigerating apparatus 10 Compared to this, according to the refrigerating apparatus 10 according to the present embodiment, it can be said that the amount of refrigerant to be used can be greatly reduced. More specifically, the refrigerating apparatus 10 according to the embodiment having a rated refrigerating capacity of 4.5 (Kw) can operate appropriately even when the amount of refrigerant charged is 0.70 Kg or more and 1.0 Kg or less. Specifically, the present inventor manufactured and operated the refrigerating apparatus 10 according to the above-described embodiment with a rated refrigerating capacity of 4.5 (Kw) and a refrigerant charging amount of 0.75 kg. I have confirmed that there are no problems.
- the above rated refrigerating capacity is calculated in accordance with JIS B 8621:2011.
- the control device 30 causes the heater control section 34 to operate the heater 24 when no-load operation or no-load operation transition operation is determined.
- the control device 30 controls whether the return temperature of the fluid flowing downstream of the heater 24 before passing through the evaporator 14 is higher than the target temperature set by the temperature setting unit 31. is small, the heater controller 34 may operate the heater 24 to heat the fluid. That is, the heater 24 may be operated when the liquid backflow risk signal described in the above embodiment is generated.
- the heater control unit 34 of the control device 30 sets the return temperature to Tb (° C.), sets the target temperature to Tt (° C.), and sets the weight flow rate of the fluid that the fluid circulation device 20 causes to flow to m (kg/s), the specific heat of the fluid is Cp (J/kg° C.), and the heating capacity Q for bringing the return temperature Tb to the target temperature Tt may be calculated from the following equation (2).
- Q m ⁇ Cp ⁇ (Tt ⁇ Tb) (2)
- control device 30 may control the heating capacity of the heater based on the heating capacity Q calculated by Equation (2).
- the heater control unit 34 controls the heating capacity of the heater 24 to be equal to or higher than the heating capacity Q calculated by the equation (2).
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Abstract
Description
前記冷凍装置を運転させる工程と、
前記圧縮機から吐出され前記凝縮器に流入する前の前記冷媒の吐出温度が閾値を上回る際に、前記液バイパス制御弁を開き、前記吐出温度が前記閾値以下である際に、前記液バイパス制御弁を閉じ、前記冷凍回路における前記蒸発器の下流側で且つ前記圧縮機の上流側の部分であって、前記液バイパス流路の下流端の接続位置の下流側の部分を流れる前記冷媒の蒸発圧力が予め設定された目標蒸発圧力になるように前記圧縮機の回転数を調節する工程と、を備える。
冷凍装置10は、圧縮機11、凝縮器12、膨張弁13及び蒸発器14が冷媒を循環させるようにこの順序で配管15により接続されることで構成される冷凍回路10Aと、冷凍回路10Aに接続される液バイパス回路16及びガスバイパス回路17と、吐出温度センサ18と、蒸発圧力センサ19と、を備えている。
流体循環装置20は、戻し口部21Uと供給口部21Dとを有するメイン流路管21を備えており、戻し口部21U及び供給口部21Dのそれぞれに接続した流路管を介して温度制御対象Tに接続している。流体循環装置20は、メイン流路管21を蒸発器14に接続しており、メイン流路管21を通流する流体を蒸発器14で熱交換させた後、温度制御対象Tに送る。そして、流体循環装置20は、温度制御対象Tを通過した流体を蒸発器14で再度熱交換させるようになっている。
制御装置30は、冷凍装置10及び流体循環装置20の動作を制御するコントローラであって、例えばCPU、ROM等を有するコンピュータで構成されてもよい。この場合、ROMに格納されたプログラムに従い、各種処理を行う。なお、制御装置30は、その他のプロセッサや電気回路(例えばFPGA(Field Programmable Gate Alley)等)で構成されてもよい。
まず、流体循環装置制御モジュール30Aについて詳しく説明する。
Q=m×Cp×(Tt-Ts)…(1)
ここで、温度制御対象Tへ供給する流体の設定温度をTs(℃)とし、流体循環装置20においてヒータ24の下流側を通流する流体であって蒸発器14を通過する前の流体の目標温度をTt(℃)とし、流体循環装置20が流体を通流させる重量流量を、m(kg/s)とし、流体の比熱を、Cp(J/kg℃)とする。なお、設定温度Tsと目標温度Ttは、温度設定部31によって設定される。また、重量流量mは、流量センサで検出してもよいし、ポンプ22の状態から特定してもよい。また、流体の比熱Cpは、予め制御装置30に保持されている。
また、制御装置30は、ヒータ24の加熱能力を、式(1)で算出した加熱能力Q以上に制御した後、ヒータ24の下流側を通流する流体であって蒸発器14を通過する前の流体の温度が目標温度Tt以上にならない場合、ヒータ24を調節してもよい。
つまり、ヒータ24の加熱能力の制御後、第3温度センサ27が検出する温度情報に基づいて、ヒータ24の下流側を通流する流体であって、蒸発器14を通過する前の流体の戻り温度が、上記目標温度よりも小さいか否かを判定し、液バックリスク信号が生成された際、ヒータ24が調節されてもよい。この際、ヒータ24の調節と同時に警告が報知されてもよい。
つづいて、冷凍装置制御モジュール35について詳しく説明する。
次に、以上のような構成を有する制御装置30が冷凍装置10を制御する際の動作の例を説明する。
本実施の形態では、冷凍回路10Aにおける蒸発器14の下流側で且つ圧縮機11の上流側の部分であって、液バイパス流路16Aの下流端の接続位置の下流側の部分を流れる冷媒の蒸発圧力が予め設定された目標蒸発圧力になるように圧縮機11の回転数を調節する。この構成では、液バイパス制御弁16Bから冷媒が圧縮機11の上流側に流れる場合に、液バイパス制御弁16Bからの冷媒が流入した後の冷媒の蒸発圧力を指標に、液バックが抑制される目標蒸発圧力への制御が行われる。これにより、液バック抑制の信頼性を向上できる。なお、変形例として、冷凍回路10Aにおける蒸発器14の下流側で且つ圧縮機11の上流側の部分であって、液バイパス流路16Aの下流端の接続位置の上流側の部分を流れる冷媒の蒸発圧力が予め設定された目標蒸発圧力になるように圧縮機11の回転数を調節する構成が採用されてもよい。
次に、図4は制御装置30の動作の一例を説明するフローチャートである。以下、図4を参照しつつ、制御装置30(ヒータ制御部34)の動作の一例を説明する。
なお、蒸発圧力が目標蒸発圧力を上回る状況は、例えば負荷が増加した場合に生じ得る。一方で、蒸発圧力が目標蒸発圧力を下回る状況は、例えば負荷が低下した場合に生じ得る。
上述したように、本実施の形態にかかる冷凍装置10によれば、使用する冷媒の量を抑制しつつも圧縮機11に吸入される冷媒の温度の過度な上昇を好適に抑制でき且つ適正な冷却動作を行うことができる。具体的に、本件発明者は、冷凍装置10の定格冷凍能力がP(Kw)であるときに、冷媒の充填量(Kg)を、0.155×P以上0.222×P以下とした場合でも、適正な運転を実施できることを確認している。なお、本件発明者の知見では、アキュムレータ及びレシーバタンクを有する一般的な冷凍装置では、定格冷凍能力がP(Kw)であるときに、(1.2×P)Kg以上の冷媒が使用される。これに比較すると、本実施の形態にかかる冷凍装置10によれば、使用する冷媒の量を大幅に抑制できると言える。より詳しくは、定格冷凍能力が4.5(Kw)とする実施の形態にかかる冷凍装置10では、冷媒の充填量が、0.70Kg以上1.0Kg以下でも適正な運転が実施され得る。具体的に本件発明者は、定格冷凍能力が4.5(Kw)であり、冷媒の充填量を0.75Kgとして上述の実施の形態にかかる冷凍装置10を作製し運転したが、これまでに不具合が生じていないことを確認している。
Q=m×Cp×(Tt-Tb)…(2)
Claims (13)
- 圧縮機、凝縮器、膨張弁及び蒸発器が冷媒を循環させるように当該順序で配管により接続された冷凍回路と、
前記冷凍回路における前記凝縮器の下流側で且つ前記膨張弁の上流側の部分から分岐し、前記蒸発器の下流側で且つ前記圧縮機の上流側の部分に接続される液バイパス流路、及び、前記液バイパス流路に設けられ前記液バイパス流路における前記冷媒の通流を制御する液バイパス制御弁を有する液バイパス回路と、
前記液バイパス制御弁及び前記圧縮機の回転数を制御する制御装置と、を備え、
前記制御装置は、前記圧縮機から吐出され前記凝縮器に流入する前の前記冷媒の吐出温度が閾値を上回る際に、前記液バイパス制御弁を開き、前記吐出温度が前記閾値以下である際に、前記液バイパス制御弁を閉じ、前記冷凍回路における前記蒸発器の下流側で且つ前記圧縮機の上流側の部分であって、前記液バイパス流路の下流端の接続位置の下流側の部分を流れる前記冷媒の蒸発圧力が予め設定された目標蒸発圧力になるように前記圧縮機の回転数を調節する、冷凍装置。 - 前記制御装置は、前記吐出温度と前記閾値との差分に応じて前記液バイパス制御弁の開度を調節する、請求項1に記載の冷凍装置。
- アキュムレータを備えていない、請求項1に記載の冷凍装置。
- 前記制御装置は、前記冷媒の蒸発圧力が前記目標蒸発圧力を上回る際に、前記圧縮機の回転数を上げ、前記冷媒の蒸発圧力が前記目標蒸発圧力を下回る際に、前記圧縮機の回転数を下げる、請求項1に記載の冷凍装置。
- 前記冷凍回路における前記圧縮機の下流側で且つ前記凝縮器の上流側の部分から分岐し、前記膨張弁の下流側で且つ前記蒸発器の上流側の部分に接続されるガスバイパス流路、及び、前記ガスバイパス流路に設けられ前記ガスバイパス流路における前記冷媒の通流を制御するガスバイパス制御弁を有するガスバイパス回路をさらに備え、
前記圧縮機の回転数が下限値まで低下され且つ前記冷媒の蒸発圧力が前記目標蒸発圧力を下回る際に、前記制御装置は、前記冷媒の蒸発圧力が前記目標蒸発圧力以上になるように前記ガスバイパス制御弁を開く、請求項4に記載の冷凍装置。 - 前記制御装置は、前記冷媒の吐出温度が前記閾値以下になるように、前記吐出温度と前記閾値との差分に応じて前記液バイパス制御弁の開度をPID制御により調節し、前記冷媒の蒸発圧力が前記目標蒸発圧力になるように前記圧縮機の回転数をPI制御により調節する、請求項2に記載の冷凍装置。
- 前記制御装置は、前記冷媒の蒸発圧力と前記目標蒸発圧力との差分に応じて前記ガスバイパス制御弁の開度を調節する、請求項5に記載の冷凍装置。
- 定格冷凍能力がP(Kw)であり、前記冷媒の充填量(Kg)が、0.155×P以上0.222×P以下である、請求項1に記載の冷凍装置。
- 定格冷凍能力が4.5Kwであり、前記冷媒の充填量が、0.70Kg以上1.0Kg以下である、請求項1に記載の冷凍装置。
- 圧縮機、凝縮器、膨張弁及び蒸発器が冷媒を循環させるように当該順序で配管により接続された冷凍回路と、前記冷凍回路における前記凝縮器の下流側で且つ前記膨張弁の上流側の部分から分岐し、前記蒸発器の下流側で且つ前記圧縮機の上流側の部分に接続される液バイパス流路、及び、前記液バイパス流路に設けられ前記液バイパス流路における前記冷媒の通流を制御する液バイパス制御弁を有する液バイパス回路と、を備える冷凍装置の制御方法であって、
前記冷凍装置を運転させる工程と、
前記圧縮機から吐出され前記凝縮器に流入する前の前記冷媒の吐出温度が閾値を上回る際に、前記液バイパス制御弁を開き、前記吐出温度が前記閾値以下である際に、前記液バイパス制御弁を閉じ、前記冷凍回路における前記蒸発器の下流側で且つ前記圧縮機の上流側の部分であって、前記液バイパス流路の下流端の接続位置の下流側の部分を流れる前記冷媒の蒸発圧力が予め設定された目標蒸発圧力になるように前記圧縮機の回転数を調節する工程と、を備える、冷凍装置の制御方法。 - 請求項1に記載の冷凍装置と、
流体を前記蒸発器で熱交換させた後、温度制御対象に送り、前記温度制御対象を通過した前記流体を前記蒸発器で再度熱交換させ、前記温度制御対象の下流側で且つ前記蒸発器の上流側の位置にヒータを有する流体循環装置と、を備える、温度制御システム。 - 前記制御装置は、前記流体循環装置も制御し、前記流体循環装置の状態が前記流体と前記温度制御対象とが熱交換しない無負荷運転又は前記無負荷運転へ移行させるための無負荷運転移行運転になった場合に、前記ヒータを作動させて前記ヒータにより前記流体を加熱する、請求項11に記載の温度制御システム。
- 圧縮機、凝縮器、膨張弁及び蒸発器が冷媒を循環させるように当該順序で配管により接続された冷凍回路と、
前記冷凍回路における前記凝縮器の下流側で且つ前記膨張弁の上流側の部分から分岐し、前記蒸発器の下流側で且つ前記圧縮機の上流側の部分に接続される液バイパス流路、及び、前記液バイパス流路に設けられ前記液バイパス流路における前記冷媒の通流を制御する液バイパス制御弁を有する液バイパス回路と、
前記液バイパス制御弁及び前記圧縮機の回転数を制御する制御装置と、を備え、
前記制御装置は、前記圧縮機から吐出され前記凝縮器に流入する前の前記冷媒の吐出温度が閾値を上回る際に、前記液バイパス制御弁を開き、前記吐出温度が前記閾値以下である際に、前記液バイパス制御弁を閉じ、前記冷凍回路における前記蒸発器の下流側で且つ前記圧縮機の上流側の部分であって、前記液バイパス流路の下流端の接続位置の上流側の部分を流れる前記冷媒の蒸発圧力が予め設定された目標蒸発圧力になるように前記圧縮機の回転数を調節する、冷凍装置。
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JPH04161758A (ja) * | 1990-10-24 | 1992-06-05 | Daikin Ind Ltd | 冷凍装置 |
JP2001280669A (ja) * | 2000-03-30 | 2001-10-10 | Mitsubishi Electric Corp | 冷凍サイクル装置 |
JP2009058200A (ja) * | 2007-09-03 | 2009-03-19 | Orion Mach Co Ltd | 冷却装置の制御方法 |
JP2017040396A (ja) * | 2015-08-18 | 2017-02-23 | 関東精機株式会社 | 冷却装置 |
WO2020066000A1 (ja) * | 2018-09-28 | 2020-04-02 | 三菱電機株式会社 | 冷凍サイクル装置の室外機、冷凍サイクル装置、及び空気調和装置 |
JP2020134052A (ja) * | 2019-02-21 | 2020-08-31 | 三菱電機株式会社 | 冷凍サイクル装置 |
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JPH04161758A (ja) * | 1990-10-24 | 1992-06-05 | Daikin Ind Ltd | 冷凍装置 |
JP2001280669A (ja) * | 2000-03-30 | 2001-10-10 | Mitsubishi Electric Corp | 冷凍サイクル装置 |
JP2009058200A (ja) * | 2007-09-03 | 2009-03-19 | Orion Mach Co Ltd | 冷却装置の制御方法 |
JP2017040396A (ja) * | 2015-08-18 | 2017-02-23 | 関東精機株式会社 | 冷却装置 |
WO2020066000A1 (ja) * | 2018-09-28 | 2020-04-02 | 三菱電機株式会社 | 冷凍サイクル装置の室外機、冷凍サイクル装置、及び空気調和装置 |
JP2020134052A (ja) * | 2019-02-21 | 2020-08-31 | 三菱電機株式会社 | 冷凍サイクル装置 |
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