WO2023175821A1 - Appareil de réfrigération et unité extérieure d'appareil de réfrigération - Google Patents

Appareil de réfrigération et unité extérieure d'appareil de réfrigération Download PDF

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Publication number
WO2023175821A1
WO2023175821A1 PCT/JP2022/012179 JP2022012179W WO2023175821A1 WO 2023175821 A1 WO2023175821 A1 WO 2023175821A1 JP 2022012179 W JP2022012179 W JP 2022012179W WO 2023175821 A1 WO2023175821 A1 WO 2023175821A1
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Prior art keywords
refrigerant
compressor
temperature
control device
heat exchanger
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PCT/JP2022/012179
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English (en)
Japanese (ja)
Inventor
裕弥 井内
寛也 石原
崇憲 八代
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三菱電機株式会社
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Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to PCT/JP2022/012179 priority Critical patent/WO2023175821A1/fr
Priority to JP2024508211A priority patent/JPWO2023176870A1/ja
Priority to PCT/JP2023/010011 priority patent/WO2023176870A1/fr
Publication of WO2023175821A1 publication Critical patent/WO2023175821A1/fr

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B1/00—Compression machines, plants or systems with non-reversible cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B7/00—Compression machines, plants or systems, with cascade operation, i.e. with two or more circuits, the heat from the condenser of one circuit being absorbed by the evaporator of the next circuit

Definitions

  • the present disclosure relates to a refrigeration system that performs both or one of a pump-down operation and a pull-down operation, and an outdoor unit of the refrigeration system.
  • an outdoor unit including a refrigeration cycle device that supplies a first refrigerant to the indoor unit and a second refrigeration cycle device that circulates a second refrigerant, and a refrigeration device that includes the outdoor unit are known (for example, , see Patent Document 1).
  • the outdoor unit performs a refrigeration operation for cooling the temperature of an object such as air or water to a set temperature by the indoor unit, and a defrosting operation for removing frost generated in a condenser in the outdoor unit.
  • operations performed by the refrigeration equipment include pump-down operation and pull-down operation.
  • the pump-down operation refers to an operation in which the first refrigerant is recovered from the indoor unit to the outdoor unit.
  • the pull-down operation refers to an operation in which the temperature of the first refrigerant is rapidly lowered in order to quickly change the target temperature to the user's desired temperature when the refrigeration system is started.
  • the pressure of the first refrigerant in the first refrigeration cycle device increases over time.
  • the first compressor for compressing the first refrigerant is operated at a high operating frequency in order to rapidly lower the temperature of the object.
  • the present disclosure has been made to solve the above problems, and provides a refrigeration system that suppresses a rise in pressure of a first refrigerant during both or one of pump-down operation and pull-down operation, and an outdoor unit of the refrigeration system.
  • the purpose is to provide.
  • a refrigeration system includes a first compressor, a first condenser, a heat exchanger, a first expansion valve, and a first evaporator, and includes a first refrigerant circuit that circulates a first refrigerant, and a second refrigerant circuit that circulates a first refrigerant.
  • a second refrigerant circuit that includes a compressor and the heat exchanger and circulates a second refrigerant; and a pump down that recovers the first refrigerant between the discharge side of the first compressor and the first expansion valve.
  • a control device that causes the first compressor to perform When heat exchange is performed between the first refrigerant and the second refrigerant, and the control device causes the first compressor to perform the first operation, the controller controls the amount of the second refrigerant in the heat exchanger.
  • the second compressor is operated so that the evaporation temperature becomes a target evaporation temperature, and the target evaporation temperature is such that the temperature of the second refrigerant flowing into the heat exchanger is equal to the temperature of the first refrigerant flowing into the heat exchanger.
  • the temperature is set by the control device to be lower than the temperature.
  • the outdoor unit of the refrigeration apparatus is an outdoor unit of the refrigeration apparatus that is provided in a first refrigerant circuit in which a first refrigerant circulates and is connected to a first expansion valve and a first evaporator.
  • a second refrigerant circuit that has a first compressor that compresses one refrigerant, a first condenser that condenses the first refrigerant, and a second compressor that circulates the second refrigerant; a heat exchanger that is provided in the second refrigerant circuit and exchanges heat between the first refrigerant and the second refrigerant, and a heat exchanger that exchanges heat between the first refrigerant and the second refrigerant; and a heat exchanger that exchanges heat between the first refrigerant and the second refrigerant; and a pull-down operation that lowers the temperature of the object to a target value when the temperature of the object exchanging heat with the first evaporator is equal to or higher than a specified value.
  • control device that causes the first compressor to perform one operation, and the heat exchanger functions as a condenser in the first refrigerant circuit and as an evaporator in the second refrigerant circuit.
  • the control device when causing the first compressor to perform the first operation, the control device operates the second compressor so that the evaporation temperature of the second refrigerant in the heat exchanger becomes a target evaporation temperature.
  • the target evaporation temperature is set by the control device so that the temperature of the second refrigerant flowing into the heat exchanger is lower than the temperature of the first refrigerant flowing into the heat exchanger.
  • the heat exchanger functions as a condenser in the first refrigerant circuit, and as an evaporator in the second refrigerant circuit, and functions as an evaporator in the first refrigerant circuit. and the second refrigerant to exchange heat.
  • the control device operates the second compressor so that the evaporation temperature of the second refrigerant in the heat exchanger becomes the target evaporation temperature during the first operation, which is either a pump-down operation or a pull-down operation. Therefore, in the first operation, the first refrigerant is cooled by the second refrigerant in the heat exchanger. Therefore, the refrigeration system and the outdoor unit of the refrigeration system can suppress an increase in the pressure of the first refrigerant.
  • FIG. 1 is a schematic diagram showing a configuration example of a refrigeration device according to Embodiment 1.
  • FIG. FIG. 6 is a Moliere diagram illustrating each of a state change of the first refrigerant in the pump-down operation of the first embodiment and a state change of the first refrigerant in the conventional pump-down operation.
  • FIG. 2 is a block diagram illustrating a hardware configuration of a first control device in Embodiment 1.
  • FIG. FIG. 2 is a block diagram illustrating a hardware configuration of a second control device in the first embodiment. 2 is a flowchart illustrating the flow of processing during pump-down operation by the refrigeration apparatus according to the first embodiment.
  • FIG. 7 is a Moliere diagram illustrating each of a state change of the first refrigerant in the pulldown operation of the second embodiment and a state change of the first refrigerant in the conventional pulldown operation.
  • 12 is a flowchart illustrating the flow of processing during pulldown operation by the refrigeration apparatus according to Embodiment 2.
  • FIG. 3 is a schematic diagram showing a configuration example of a refrigeration device according to a third embodiment.
  • FIG. 7 is a block diagram illustrating a hardware configuration of a third control device in Embodiment 3.
  • FIG. FIG. 7 is a schematic diagram showing a configuration example of a second refrigerant circuit in Embodiment 4.
  • FIG. 1 is a schematic diagram showing a configuration example of a refrigeration system according to a first embodiment.
  • Refrigeration apparatus 100 includes a first refrigerant circuit 1 in which a first refrigerant circulates, and a second refrigerant circuit 2 in which a second refrigerant circulates.
  • the refrigeration system 100 includes an outdoor unit 3 and an indoor unit 4 provided in the first refrigerant circuit 1 . Note that the outdoor unit 3 and the indoor unit 4 are connected to each other by a first refrigerant pipe 5.
  • the first refrigerant circuit 1 includes a first compressor 10, a first condenser 11, a heat exchanger 12, a first expansion valve 13, and a first evaporator 14, which are connected in sequence by a first refrigerant pipe 5.
  • the first compressor 10, the first condenser 11, and the heat exchanger 12 are arranged inside a casing forming the outer shell of the outdoor unit 3, which is indicated by a rectangle indicated by a chain line in FIG. That is, the outdoor unit 3 includes the first compressor 10, the first condenser 11, and the heat exchanger 12. However, the heat exchanger 12 may be installed outside the outdoor unit 3.
  • the first expansion valve 13 and the first evaporator 14 are arranged inside a casing forming the outer shell of the indoor unit 4, which is indicated by a square with two-dot chain lines in FIG. That is, the indoor unit 4 includes the first expansion valve 13 and the first evaporator 14 .
  • the second refrigerant circuit 2 includes a second compressor 20, a second condenser 21, a second expansion valve 22, and a heat exchanger 12, which are connected in sequence by a second refrigerant pipe 6.
  • the first compressor 10 sucks the first refrigerant from the first refrigerant pipe 5 and compresses the sucked first refrigerant. The first compressor 10 then discharges the compressed first refrigerant to the first refrigerant pipe 5.
  • the first compressor 10 is, for example, an inverter compressor whose capacity can be controlled by an inverter.
  • the first condenser 11 cools and condenses the first refrigerant by exchanging heat between the first refrigerant and air or water.
  • the first condenser 11 in the first embodiment exchanges heat between the outside air and the first refrigerant.
  • the heat exchanger 12 functions as a condenser in the first refrigerant circuit 1 and functions as an evaporator in the second refrigerant circuit 2.
  • the first refrigerant flowing out from the first condenser 11 exchanges heat with the second refrigerant in the heat exchanger 12 and is further cooled.
  • the second refrigerant absorbs heat from the first refrigerant in the heat exchanger 12 and evaporates.
  • the first expansion valve 13 reduces the pressure of the first refrigerant and expands it.
  • the first expansion valve 13 is, for example, an electric expansion valve that can adjust the flow rate of the first refrigerant.
  • the first evaporator 14 exchanges heat between the first refrigerant brought into a low pressure state by the first expansion valve 13 and an object, such as air or water, whose temperature the user desires to adjust, thereby cooling the object.
  • the first refrigerant absorbs heat from the object in the first evaporator 14 and evaporates.
  • the second compressor 20 sucks refrigerant from the second refrigerant pipe 6 and compresses the sucked second refrigerant. The second compressor 20 then discharges the compressed second refrigerant to the second refrigerant pipe 6.
  • the second compressor 20 is, for example, an inverter compressor whose capacity can be controlled by an inverter.
  • the second condenser 21 cools and condenses the second refrigerant by exchanging heat between the second refrigerant and air or water.
  • the second expansion valve 22 reduces the pressure of the second refrigerant and expands it.
  • the second expansion valve 22 is, for example, an electric expansion valve that can adjust the flow rate of the second refrigerant.
  • the second refrigerant brought into a low pressure state by the second expansion valve 22 flows into the heat exchanger 12 .
  • the refrigeration system 100 includes a first control device 7 that controls the first compressor 10 within the casing of the outdoor unit 3.
  • the first control device 7 in the first embodiment causes the first compressor 10 to perform a pump-down operation.
  • the pump-down operation is an operation in which the first refrigerant is recovered from the indoor unit 4 to the outdoor unit 3.
  • the pump-down operation means that the first compressor 10 sucks the first refrigerant in the indoor unit 4 through the first refrigerant pipe 5, and the first expansion valve This is an operation in which the first refrigerant is recovered during the period up to 13.
  • the first expansion valve 13 is brought into a closed state under the control of the first control device 7, and the first refrigerant from the outdoor unit 3 is cut off.
  • the pump down operation is an example of the first operation.
  • the first refrigerant circuit 1 may be provided with a liquid receiver (not shown) between the heat exchanger 12 and the first expansion valve 13. may store the first refrigerant.
  • the first refrigerant During pump-down operation, the first refrigerant accumulates in the outdoor unit 3 over time. Therefore, the pressure of the first refrigerant to the first refrigerant pipe 5 and the like in the outdoor unit 3 may increase over time. Furthermore, when the outside temperature is high, the pressure of the first refrigerant discharged from the first compressor 10 may increase excessively. On the other hand, the pressure and temperature of the first refrigerant discharged from the first compressor 10 have a predetermined allowable range. The permissible range is determined based on the design pressure of the components included in the refrigeration system 100, such as the first refrigerant pipe 5 and the first condenser 11.
  • the upper limit of the allowable range of the pressure of the first refrigerant discharged from the first compressor 10 is determined to be less than the design pressure. If the pressure of the first refrigerant discharged from the first compressor 10 deviates from the permissible range and reaches the design pressure, damage to the components may occur. In order to avoid such a situation, refrigeration apparatus 100 according to Embodiment 1 has the following configuration.
  • the refrigeration apparatus 100 further includes a first pressure detection device 30, a first temperature detection device 31, a second pressure detection device 40, and a second control device 8. Note that the combination of the first control device 7 and the second control device 8 is an example of a control device.
  • the first pressure detection device 30 is, for example, a pressure sensor, and as shown in FIG. It is provided in the refrigerant pipe 5 and detects the pressure of the first refrigerant discharged by the first compressor 10.
  • the first pressure sensing device 30 may be provided in the first refrigerant pipe 5 downstream of the first condenser 11 and upstream of the heat exchanger 12; in this case, the first pressure sensing device 30 Detecting the pressure of the first refrigerant after condensation.
  • the first pressure sensing device 30 is connected to the first control device 7 by wire, and periodically outputs detection results to the first control device 7.
  • the first pressure detection device 30 may communicate wirelessly with the first control device 7, and in this case, the first pressure detection device 30 periodically detects the pressure with respect to the first control device 7 by wireless communication. Submit your results.
  • the first temperature detection device 31 is, for example, a thermistor, and as shown in FIG. It is provided in the pipe 5 and detects the temperature of the first refrigerant discharged by the first compressor 10.
  • the first temperature detection device 31 may be provided in the first refrigerant pipe 5 downstream of the first condenser 11 and upstream of the heat exchanger 12; in this case, the first temperature detection device 31 Detecting the temperature of the first refrigerant after condensation.
  • the first temperature detection device 31 is connected to the first control device 7 by wire, and periodically outputs a detection result to the first control device 7.
  • the first temperature detection device 31 may communicate wirelessly with the first control device 7. In this case, the first temperature detection device 31 periodically transmits the detection results to the first control device 7 via wireless communication.
  • the second pressure detection device 40 is, for example, a pressure sensor, and is provided in the second refrigerant pipe 6 downstream of the heat exchanger 12 and upstream of the second compressor 20, as shown in FIG. , the pressure of the second refrigerant flowing out from the heat exchanger 12 is detected.
  • the second pressure detection device 40 is connected to the second control device 8 by wire, and periodically outputs detection results to the second control device 8.
  • the second pressure detection device 40 may communicate wirelessly with the second control device 8. In this case, the second pressure detection device 40 periodically detects the pressure on the second control device 8 by wireless communication. Submit your results.
  • the second control device 8 controls the second compressor 20 and the second expansion valve 22. Note that the second control device 8 controls the second compressor 20 and the second expansion valve 22 in conjunction with each other. Further, the second control device 8 controls the operating frequency of the second compressor 20 and the opening degree of the second expansion valve 22 in a stepwise manner. When the second condenser 21 is air-cooled, the second control device 8 controls the blower provided in the second condenser 21 in conjunction with the second compressor 20 and the second expansion valve 22. . That is, the second control device 8 controls the rotation speed of the blower in accordance with the operating frequency of the second compressor 20 and the opening degree of the second expansion valve 22.
  • the second control device 8 according to the first embodiment performs wireless communication or wired communication with the first control device 7.
  • the first control device 7 When causing the first compressor 10 to perform a pump-down operation, the first control device 7 transmits pump-down operation information indicating execution of the pump-down operation to the second control device 8 .
  • the pump-down operation information may be information that instructs the second compressor 20 to operate.
  • Pump-down operation information is an example of first operation information.
  • the second control device 8 causes the second compressor 20 to start operating.
  • the second control device 8 causes the second compressor 20 to continue operating when the pump-down operation information is received while the second compressor 20 is operating.
  • the second control device 8 acquires the evaporation temperature of the second refrigerant in the heat exchanger 12 based on the pressure detected by the second pressure detection device 40, and controls the second refrigerant so that the acquired evaporation temperature becomes the target evaporation temperature.
  • the compressor 20 is operated.
  • the target evaporation temperature is set by the second control device 8 so that the evaporation temperature of the second refrigerant in the heat exchanger 12 is lower than the temperature of the first refrigerant flowing into the heat exchanger 12.
  • the second control device 8 obtains the temperature of the first refrigerant flowing into the heat exchanger 12 based on the detection results obtained from both or one of the first pressure detection device 30 and the first temperature detection device 31.
  • the first refrigerant pipe 5 between the first condenser 11 and the heat exchanger 12 there is a device that detects either the temperature of the first refrigerant or a physical quantity that can be converted into the temperature of the first refrigerant.
  • a first temperature acquisition device such as the illustrated sensor may be provided, and the second control device 8 receives the detection result from the first temperature acquisition device directly or via the first control device 7. You may obtain it.
  • the target evaporation temperature may be set such that the temperature of the second refrigerant flowing into the heat exchanger 12 is lower than the temperature of the first refrigerant flowing into the heat exchanger 12.
  • a second temperature acquisition device such as a sensor (not shown) that detects either the temperature of the second refrigerant or a physical quantity that can be converted into the temperature of the second refrigerant is connected to the second expansion valve 22.
  • the second control device 8 may be provided between the heat exchanger 12 and the second temperature acquisition device, and the second control device 8 may acquire the detection result from the second temperature acquisition device.
  • the target evaporation temperature may be set such that the temperature of the second refrigerant flowing out of the heat exchanger 12 is lower than the temperature of the first refrigerant flowing into the heat exchanger 12.
  • a third temperature acquisition device such as a sensor (not shown) that detects the temperature of the second refrigerant or a physical quantity convertible to the temperature of the second refrigerant connects the heat exchanger 12 and the second compressor 20.
  • the second control device 8 may acquire the detection result from the second temperature acquisition device.
  • the first control device 7 transmits the detection results obtained from each of the first pressure detection device 30 and the first temperature detection device 31, the first threshold pressure, and the first threshold temperature to the second control device 8.
  • the first threshold pressure is the upper limit pressure of the allowable range of the pressure of the first refrigerant discharged from the first compressor 10.
  • the first threshold pressure is, for example, 3. .38 [MPa].
  • the first threshold temperature is the upper limit temperature of the allowable range of the temperature of the first refrigerant discharged from the first compressor 10.
  • the first control device 7 transmits the obtained detection results to the second control device 8 every time it obtains detection results from each of the first pressure detection device 30 and the first temperature detection device 31.
  • the first control device 7 may transmit the detection result to the second control device 8 only while the pump-down operation is being executed.
  • the first control device 7 transmits the first threshold pressure and the first threshold temperature to the second control device 8 at the start of the pump-down operation or prior to the pump-down operation.
  • the second control device 8 performs wired communication or wireless communication with each of the first pressure detection device 30 and the first temperature detection device 31, and communicates with the first pressure detection device 30 and the first temperature detection device 31 without using the first control device 7.
  • the detection results may be obtained directly from each of the temperature detection devices 31.
  • the second control device 8 satisfies the first condition that the pressure detected by the first pressure detection device 30 is higher than the first threshold pressure, and that the temperature detected by the first temperature detection device 31 is higher than the first threshold temperature. It is determined whether both or one of the second conditions is true. When both or one of the first condition and the second condition is satisfied, the second control device 8 lowers the target evaporation temperature of the second refrigerant in the heat exchanger 12. At this time, the second control device 8 determines the amount of decrease in the target evaporation temperature based on both or one of the pressure detected by the first pressure detection device 30 and the temperature detected by the first temperature detection device 31. do.
  • the second control device 8 controls the difference between the pressure detected by the first pressure detection device 30 and the first threshold pressure, and the difference between the temperature detected by the first temperature detection device 31 and the first threshold temperature. How much to lower the target evaporation temperature is determined based on either or both of the following.
  • the second control device 8 controls the second compressor 20 so that the evaporation temperature of the second refrigerant in the heat exchanger 12 reaches the target evaporation temperature after the decrease.
  • the second compressor 20 operates at an increased operating frequency under the control of the second control device 8 so that the evaporation temperature of the second refrigerant in the heat exchanger 12 reaches the target evaporation temperature after the decrease.
  • the evaporation temperature of the second refrigerant in the heat exchanger 12 decreases, and the condensation temperature of the first refrigerant decreases. Thereby, the temperature of the first refrigerant flowing out from the heat exchanger 12 decreases. As the temperature of the first refrigerant flowing out from the heat exchanger 12 decreases, both or one of the pressure and temperature of the first refrigerant discharged from the first compressor 10 may decrease.
  • FIG. 2 is a Moliere diagram illustrating a state change of the first refrigerant in the pump-down operation of the first embodiment and a state change of the first refrigerant in the conventional pump-down operation. Note that although FIG. 2 illustrates a Molière diagram when the first refrigerant is R410A, the first refrigerant is not limited to R410A.
  • the refrigeration system does not include the heat exchanger 12, the second compressor 20, etc., or the second compressor 20 does not operate during pump-down operation.
  • the conventional refrigeration system has a configuration in which the second refrigerant circuit 2 is omitted from the configuration of the refrigeration system 100 illustrated in FIG. 1 .
  • the conventional refrigeration system has a configuration in which the heat exchanger 12 is omitted from the first refrigerant circuit 1.
  • the conventional refrigeration system has a configuration illustrated in FIG. 1 as in the first embodiment, but the second compressor 20 does not operate during pump-down operation.
  • the first refrigerant discharged from the first compressor 10 is cooled only in the first condenser 11 by, for example, outside air. It had been.
  • the horizontal axis in FIG. 2 shows the enthalpy [kJ/kg] of the first refrigerant
  • the vertical axis shows the pressure [MPa] of the first refrigerant.
  • the first refrigerant exchanges heat with outside air having a temperature of 40 [° C.] in the first condenser 11.
  • the first refrigerant is assumed to be condensed at 50[° C.] by heat exchange with outside air at 40[°C].
  • the evaporation temperature of the second refrigerant in the heat exchanger 12 is set to 0 [°C]
  • the condensation temperature of the first refrigerant in this case is set to 10 [°C]. Note that the condensation temperature of the first refrigerant becomes lower as the temperature of a substance such as the outside air or the second refrigerant that performs heat exchange is lower.
  • the state change of the conventional first refrigerant is indicated by a rectangle formed by a solid line connecting points A, B, C, and D shown in FIG. 2 in this order.
  • the state change of the first refrigerant in the first embodiment is indicated by a rectangle formed by a broken line connecting points A, E, F, G, and H shown in FIG. 2 in this order.
  • Point A indicates the state of the first refrigerant after flowing out from the first evaporator 14 and before being sucked into the first compressor 10.
  • Point B shows the state of the first refrigerant discharged from the first compressor 10 during conventional pump-down operation.
  • Point C shows the state of the first refrigerant flowing out from the first condenser 11 during conventional pump-down operation.
  • Point D shows the state of the first refrigerant after it flows out from the first expansion valve 13 and before it flows into the first evaporator 14 during conventional pump-down operation.
  • Point E indicates the state of the first refrigerant discharged from the first compressor 10 during the pump-down operation of the first embodiment.
  • Point F indicates the state of the first refrigerant flowing out from the first condenser 11 during the pump-down operation of the first embodiment.
  • Point G indicates the state of the first refrigerant flowing out from the heat exchanger 12 during the pump-down operation of the first embodiment.
  • Point H indicates the state of the first refrigerant after flowing out from the first expansion valve 13 and before flowing into the first evaporator 14 during the pump-down operation of the first embodiment.
  • the first refrigerant is condensed at 50 [°C] by heat exchange with outside air at 40 [°C]. It was necessary to raise the discharge temperature to 110 [°C]. As point B shows, the pressure of the first refrigerant at 110 [° C.] exceeds 3 [MPa], and there is a possibility that the temperature and pressure of the first refrigerant exceed the permissible range. Therefore, conventionally, pump-down operation was sometimes performed with the operating frequency of the first compressor 10 lowered. As a result, there was a possibility that the pump down operation would not be completed quickly.
  • the second refrigerant evaporates at 0 [°C] in the heat exchanger 12, and the first refrigerant condenses at 10 [°C].
  • the temperature of the first refrigerant decreases to 40 [°C], which is equivalent to the outside air temperature, by heat exchange with the outside air in the first condenser 11, and the temperature changes from point E to point F. Change.
  • the first refrigerant condenses at 10 [°C] by heat exchange with the second refrigerant in the heat exchanger 12, and changes from a temperature of 40 [°C] indicated by point F to a temperature of 0 [°C] indicated by point G. °C] becomes a supercooled state.
  • the discharge temperature of the first refrigerant from the first compressor 10 is suppressed to 60 [° C.] as indicated by point E. Further, the discharge pressure of the first refrigerant from the first compressor 10 is suppressed to a range of 1.0 to 1.5 [MPa], as indicated by point E. Therefore, the discharge pressure and discharge temperature of the first refrigerant from the first compressor 10 fall within the permissible range.
  • Gr in formula (1) is the flow rate of the first refrigerant in the heat exchanger 12.
  • H1 is the maximum enthalpy of the first refrigerant in the heat exchanger 12.
  • the maximum enthalpy is approximately 455 [kJ/kg], which is indicated by point F in FIG.
  • H2 is the minimum enthalpy of the first refrigerant in the heat exchanger 12.
  • the minimum enthalpy is 200 [kJ/kg], which is indicated by point G in FIG.
  • the second control device 8 of the first embodiment detects the difference between the pressure detected by the first pressure detection device 30 and the first threshold pressure, and the temperature detected by the first temperature detection device 31 and the first threshold temperature.
  • the target evaporation temperature is adjusted based on one or both of the differences between Note that, as described above, the condensation temperature of the first refrigerant in the heat exchanger 12 corresponds to the evaporation temperature of the second refrigerant. Therefore, the second control device 8 adjusts the discharge pressure of the first refrigerant from the first compressor 10 based on the pressure detected by the first pressure detection device 30 and the temperature detected by the first temperature detection device 31. A necessary condensation temperature of the first refrigerant is obtained and a target evaporation temperature is determined so that the discharge temperature is within an allowable range.
  • the second control device 8 obtains the necessary refrigerating capacity Q based on equation (1) and the target evaporation temperature. Then, the second control device 8 obtains a necessary value as the operating frequency of the second compressor 20 based on the refrigeration capacity Q. Note that the second control device 8 is directly connected to the first control device from a flow rate detection device (not shown), such as a flow rate sensor, which is provided in the first refrigerant circuit 1 and detects the flow rate of the first refrigerant. 7 to obtain the detection results. The flow rate corresponds to Gr in equation (1). Further, the second control device 8 acquires information regarding the refrigerating capacity of the first condenser 11 from the first control device 7 and the like.
  • the second control device 8 may increase the operating frequency of the second compressor 20 without determining the target evaporation temperature when both or one of the first condition and the second condition are satisfied. That is, the second control device 8 adjusts the operating frequency of the second compressor 20 based on both or one of the pressure detected by the first pressure detection device 30 and the temperature detected by the first temperature detection device 31. An increment may be determined. In this case, the second control device 8 may store first correspondence information that associates both or one of the pressure and temperature of the first refrigerant with the operating frequency of the second compressor 20.
  • the operating frequency associated with both or one of the pressure detected by the first pressure detection device 30 and the temperature detected by the first temperature detection device 31 is the operating frequency associated with the pressure detected by the first pressure detection device 30 and the temperature detected by the first temperature detection device 31.
  • the operating frequency of the second compressor 20 is required to change the pressure and temperature of the first refrigerant discharged from the first compressor 10 within an allowable range, and is determined through experiments or the like.
  • the first correspondence information is an example of correspondence information.
  • the second control device 8 refers to the first correspondence information and performs the second compression based on both or one of the pressure detected by the first pressure detection device 30 and the temperature detected by the first temperature detection device 31.
  • the operating frequency of machine 20 may be increased.
  • the second control device 8 may then operate the second compressor 20 at the increased operating frequency.
  • the second control device 8 increases the operating frequency of the second compressor 20 to the maximum in a state where both or one of the first condition and the second condition are satisfied, the first control device 7 When both or one of the condition and the second condition are satisfied, the operating frequency of the first compressor 10 is lowered.
  • the first control device 7 determines that the pressure detected by the first pressure detection device 30 is less than the second threshold pressure and the temperature detected by the first temperature detection device 31 is less than the second threshold temperature. If the three conditions are met, the operating frequency of the first compressor 10 may be increased. In this case, the first control device 7 operates the first compressor 10 at the increased operating frequency.
  • the second threshold pressure is predetermined and is equal to or lower than the first threshold pressure.
  • the second threshold temperature is predetermined and is equal to or lower than the first threshold temperature.
  • FIG. 3 is a block diagram illustrating the hardware configuration of the first control device in the first embodiment.
  • FIG. 4 is a block diagram illustrating the hardware configuration of the second control device in the first embodiment.
  • the first control device 7 includes, for example, a first processor 71, a first memory 72, a first communication interface circuit 73, a first input interface circuit 74, and a first output interface circuit 75, which are connected to each other by a first bus 70.
  • the first processor 71 is a CPU (Central Processing Unit), an MPU (Micro Processing Unit), or the like.
  • the first memory 72 is a ROM (Read Only Memory), a RAM (Random Access Memory), or the like.
  • the communication function of the first control device 7 with the second control device 8 can be realized by the first communication interface circuit 73.
  • the function of acquiring detection results from each of the first pressure sensing device 30 and the first temperature sensing device 31 by the first control device 7 can be realized by the first input interface circuit 74.
  • the function of the first control device 7 to perform processing based on the detection results etc. from each of the first pressure sensing device 30 and the first temperature sensing device 31 is stored in the first memory 72 by the first processor 71. This can be achieved by reading and executing various programs and data.
  • the control function of the first compressor 10, the first expansion valve 13, etc. by the first control device 7 is performed by a first output interface circuit 75 connected by wire to the first compressor 10, the first expansion valve 13, etc.
  • the first control device 7 may control the first compressor 10, the first expansion valve 13, etc. by wireless communication, and in this case, the first control device 7 includes a first output interface circuit 75. Instead, a first wireless communication interface circuit is included.
  • the functions of the first control device 7 may be realized by dedicated hardware such as a CPLD (Complex Programmable Logic Device) or an FPGA (Field Programmable Gate Array).
  • CPLD Complex Programmable Logic Device
  • FPGA Field Programmable Gate Array
  • the second control device 8 can be configured by, for example, a second processor 81, a second memory 82, a second communication interface circuit 83, and a second output interface circuit 84, which are connected to each other by a second bus 80.
  • the second processor 81 is a CPU, an MPU, or the like.
  • the second memory 82 is a ROM, RAM, or the like.
  • the communication function of the second control device 8 with the first control device 7 can be realized by the second communication interface circuit 83.
  • the function of the second controller 8 such as determining the target evaporation temperature based on the detection results etc. by the first pressure sensing device 30 and the first temperature sensing device 31 is carried out by the second processor 81 in the second memory 82. This can be realized by reading and executing various programs, data, etc. stored in the computer.
  • the control function of the second compressor 20, the second expansion valve 22, etc. by the second control device 8 is performed by a second output interface circuit 84 connected by wire to the second compressor 20, a second processor 81, and a second memory. 82.
  • the second control device 8 may control the second compressor 20, the second expansion valve 22, etc. by wireless communication, and in this case, the second control device 8 includes a second output interface circuit 84. Instead, a second wireless communication interface circuit is included.
  • all or part of the functions of the second control device 8 may be realized by dedicated hardware such as a CPLD or FPGA.
  • FIG. 5 is a flowchart illustrating the flow of processing during pump-down operation by the refrigeration system according to the first embodiment.
  • the first control device 7 determines whether pump down operation is being performed.
  • the first control device 7 can determine whether the pump-down operation is being performed in the following manner. First, the first control device 7 is set with operation modes associated with respective operations such as refrigeration operation and pump-down operation. If the operation mode corresponding to the pump-down operation is selected, the first control device 7 determines that the pump-down operation is being performed.
  • the first control device 7 determines that the pump down operation is being performed by receiving a signal indicating the closed state from the first expansion valve 13. You may.
  • a solenoid valve (not shown) is provided upstream of the first expansion valve 13, and the first control device 7 performs pump-down operation by receiving a signal from the solenoid valve that is in the closed state. It may be determined that the
  • step S1 If the pump down operation is not being performed (step S1: NO), the refrigeration apparatus 100 returns the process to step S1. Note that if the pump-down operation is not being executed and the refrigeration apparatus 100 is executing other processes other than those shown in FIG. 5 in parallel with the process of step S1, the refrigeration apparatus 100 , continue executing the other process.
  • the second control device 8 controls the second compressor 20, the second expansion valve 22, etc. based on the detection results from the first pressure detection device 30 and the first temperature detection device 31, respectively. Good too.
  • the second control device 8 may perform the determination process in step S1. In this case, the second control device 8 may periodically acquire information indicating the operation mode corresponding to the operation in progress from the first control device 7, or each time the operation is started, the second control device 8 may obtain information indicating the operation mode corresponding to the operation in progress. Information indicating the corresponding driving mode may also be acquired. Alternatively, the second control device 8 may receive a signal indicating the closed state from the first expansion valve 13 or a solenoid valve (not shown) directly or via the first control device 7.
  • step S1 If the pump-down operation is being performed (step S1: YES), the second control device 8 determines whether the second compressor 20 is operating in step S2. If the second compressor 20 is operating (step S2: YES), the refrigeration system 100 moves the process to step S4. If the second compressor 20 is not operating (step S2: NO), the second control device 8 operates the second compressor 20 in step S3. In step S4, the second control device 8 determines whether both or one of the first condition and the second condition described above is satisfied. If both the first condition and the second condition are not satisfied (step S4: NO), the refrigeration apparatus 100 returns the process to step S1.
  • the first control device 7 or the second control device 8 may determine whether the third condition is satisfied.
  • the first control device 7 may acquire the determination result from the second control device 8.
  • the first control device 7 transmits information indicating that the first condition and the second condition are not satisfied to the second control device 7. It may be determined whether or not the third condition is met based on reception from the third condition. If the third condition is satisfied, the first control device 7 may increase the operating frequency of the first compressor 10 and operate the first compressor 10 at the increased operating frequency.
  • step S5 the second control device 8 determines whether the operating frequency of the second compressor 20 is the maximum or not. Determine whether If the operating frequency of the second compressor 20 is the maximum (step S5: YES), the first control device 7 lowers the operating frequency of the first compressor 10 in step S6, and maintains the operating frequency after the reduction. The first compressor 10 is operated. After the process in step S6, the refrigeration apparatus 100 returns the process to step S1. If the operating frequency of the second compressor 20 is not the maximum (step S5: NO), the second control device 8 increases the operating frequency of the second compressor 20 in step S7, and at the increased operating frequency. The second compressor 20 is operated. After the process in step S7, the refrigeration apparatus 100 returns the process to step S1.
  • Embodiment 2 the refrigeration apparatus 100 according to the second embodiment will be described in detail.
  • the same reference numerals are given to the same components as those in the first embodiment.
  • descriptions of configurations similar to those in the first embodiment, functions similar to those in the first embodiment, etc. will be omitted unless there are special circumstances.
  • FIG. 1 The configuration of the refrigeration apparatus 100 according to the second embodiment is illustrated by FIG. 1, as in the first embodiment.
  • the hardware configuration of the first control device 7 in the second embodiment is illustrated in FIG. 3 as in the first embodiment.
  • the hardware configuration of the second control device 8 in the second embodiment is illustrated in FIG. 4 as in the first embodiment.
  • the refrigeration apparatus 100 executes a pull-down operation. That is, the first control device 7 causes the first compressor 10 to perform a pull-down operation.
  • the pull-down operation is an operation in which the target temperature is lowered to a target value when it is equal to or higher than a specified value. Specifically, when the target is indoor air, the temperature of the target is often equal to the outside air temperature when the refrigeration system 100 is installed, and the pull-down operation is performed to adjust the temperature of the target to the set temperature desired by the user. Refers to operation that reduces the The specified value is, for example, the value of the outside temperature, and the target value is the value of the set temperature.
  • the first control device 7 When causing the first compressor 10 to perform a pulldown operation, the first control device 7 transmits pulldown operation information indicating execution of the pulldown operation to the second control device 8.
  • the pulldown operation information may be information that instructs the second compressor 20 to perform the operation.
  • the pull-down driving information is an example of the first driving information.
  • the second control device 8 When the second control device 8 receives the pull-down operation information, it causes the second compressor 20 to perform the operation. In this case, the second control device 8 operates the second compressor 20 so that the evaporation temperature of the second refrigerant in the heat exchanger 12 becomes the target evaporation temperature.
  • the second control device 8 acquires the first threshold pressure and the first threshold temperature from the first control device 7, such as at the start of the pull-down operation.
  • the second control device 8 acquires the detection result of the first pressure detection device 30 from the first pressure detection device 30 directly or via the first control device 7 .
  • the second control device 8 acquires the detection result of the first temperature detection device 31 from the first temperature detection device 31 directly or via the first control device 7 .
  • the second control device 8 determines whether both or one of the first condition and the second condition is satisfied during pull-down operation. When both or one of the first condition and the second condition is satisfied, the second control device 8 lowers the target evaporation temperature of the second refrigerant in the heat exchanger 12. The second control device 8 determines the amount of decrease in the target evaporation temperature based on both or one of the pressure detected by the first pressure detection device 30 and the temperature detected by the first temperature detection device 31. The second control device 8 controls the second compressor 20 so that the evaporation temperature of the second refrigerant in the heat exchanger 12 reaches the target evaporation temperature after the decrease. The second compressor 20 operates at an increased operating frequency under the control of the second control device 8 so that the evaporation temperature of the second refrigerant in the heat exchanger 12 reaches the target evaporation temperature after the decrease.
  • the second control device 8 may increase the operating frequency of the second compressor 20 without determining the target evaporation temperature when both or one of the first condition and the second condition are satisfied.
  • the second control device 8 may store second correspondence information that associates both or one of the pressure and temperature of the first refrigerant with the operating frequency of the second compressor 20.
  • the operating frequency associated with both or one of the pressure detected by the first pressure detection device 30 and the temperature detected by the first temperature detection device 31 is the first compression frequency during the pull-down operation. This is the operating frequency of the second compressor 20 necessary to change the pressure and temperature of the first refrigerant discharged from the compressor 10 within an allowable range, and is determined through experiments or the like.
  • the second correspondence information is an example of correspondence information.
  • the second control device 8 refers to the second correspondence information, and based on both or one of the pressure detected by the first pressure detection device 30 and the temperature detected by the first temperature detection device 31.
  • the operating frequency of the second compressor 20 may be increased.
  • the second control device 8 may then operate the second compressor 20 at the increased operating frequency.
  • the first control device 7 is configured to control the first condition.
  • the operating frequency of the first compressor 10 is lowered and the opening degree of the first expansion valve 13 is reduced.
  • the degree of superheating of the first refrigerant after flowing out from the first evaporator 14 may be high.
  • both or one of the pressure and temperature of the first refrigerant discharged from the first compressor 10 may exceed the allowable range.
  • the evaporation temperature of the second refrigerant in the heat exchanger 12 decreases, so the temperature of the first refrigerant flowing out from the heat exchanger 12 decreases.
  • both or one of the pressure and temperature of the first refrigerant discharged from the first compressor 10 may decrease.
  • FIG. 6 is a Moliere diagram illustrating a state change of the first refrigerant in the pull-down operation of the second embodiment and a state change of the first refrigerant in the conventional pull-down operation. Note that although FIG. 6 illustrates a Molière diagram when the first refrigerant is R410A, the first refrigerant is not limited to R410A.
  • the refrigeration system does not include the heat exchanger 12, the second compressor 20, etc., or the second compressor 20 does not operate during pull-down operation.
  • the conventional refrigeration system eliminates the second refrigerant circuit 2 from the configuration of the refrigeration system 100 illustrated in FIG. The configuration is such that the heat exchanger 12 is omitted from the first refrigerant circuit 1.
  • the second compressor 20 does not operate during pull-down operation in the conventional refrigeration system, the configuration of which is illustrated in FIG. Regardless of whether it is the former case or the latter case, in conventional pull-down operation, the first refrigerant discharged from the first compressor 10 is cooled only in the first condenser 11 by, for example, outside air. was.
  • the horizontal axis in FIG. 6 shows the enthalpy [kJ/kg] of the first refrigerant
  • the vertical axis shows the pressure [MPa] of the first refrigerant.
  • a case where the first refrigerant exchanges heat with outside air at a temperature of 40 [° C.] in the first condenser 11 will be described as an example. Further, it is assumed that the first refrigerant is condensed at 50 [°C] by heat exchange with outside air at 40 [°C]. Then, the evaporation temperature of the second refrigerant in the heat exchanger 12 is set to 0 [°C], and the condensation temperature of the first refrigerant in this case is set to 10 [°C].
  • the state change of the first refrigerant during conventional pull-down operation is shown by a rectangle formed by a solid line connecting points I, J, K, and L shown in FIG. 6 in this order.
  • the state change of the first refrigerant during the pull-down operation of the second embodiment is shown by a rectangle formed by a broken line connecting points I, M, N, O, and P in this order in FIG. It will be done.
  • Point I indicates the state of the first refrigerant after flowing out from the first evaporator 14 and before being sucked into the first compressor 10.
  • Point J indicates the state of the first refrigerant discharged from the first compressor 10 during conventional pull-down operation.
  • Point K shows the state of the first refrigerant flowing out from the first condenser 11 during conventional pull-down operation.
  • Point L indicates the state of the first refrigerant after it flows out from the first expansion valve 13 and before it flows into the first evaporator 14 during conventional pull-down operation.
  • Point M indicates the state of the first refrigerant discharged from the first compressor 10 during the pull-down operation of the second embodiment.
  • Point N indicates the state of the first refrigerant flowing out from the first condenser 11 during the pull-down operation of the second embodiment.
  • Point O indicates the state of the first refrigerant flowing out from the heat exchanger 12 during the pull-down operation of the second embodiment.
  • Point P indicates the state of the first refrigerant after flowing out from the first expansion valve 13 and before flowing into the first evaporator 14 during the pull-down operation of the second embodiment.
  • the first refrigerant is condensed at 50 [°C] by heat exchange with outside air at 40 [°C], so the first compressor 10, as indicated by point J, It was necessary to raise the discharge temperature to 110 [°C].
  • the pressure of the first refrigerant at 110 [° C.] exceeds 3 [MPa], and there is a possibility that the temperature and pressure of the first refrigerant exceed the permissible range. Therefore, in the past, pull-down operation was sometimes performed with the operating frequency of the first compressor 10 lowered. As a result, it sometimes took a long time for the temperature of the object to reach the set temperature.
  • the second refrigerant evaporates at 0 [°C], and the first refrigerant condenses at 10 [°C].
  • the temperature of the first refrigerant decreases to 40 [°C], which is equivalent to the outside air temperature, by heat exchange with the outside air in the first condenser 11, and the state changes from point M to point N. Change.
  • the first refrigerant condenses at 10 [°C] by heat exchange with the second refrigerant in the heat exchanger 12, and changes from a temperature of 40 [°C] indicated by point N to a temperature of 0 [°C] indicated by point O. °C] becomes a supercooled state.
  • the discharge temperature of the first refrigerant from the first compressor 10 is suppressed to 60 [° C.] as indicated by point M. Furthermore, the discharge pressure of the first refrigerant from the first compressor 10 is suppressed to a range of 1.0 to 1.5 [MPa], as indicated by point M. Therefore, the discharge pressure and discharge temperature of the first refrigerant from the first compressor 10 fall within the permissible range.
  • Points R and S in FIG. 6 indicate the state of the first refrigerant when the degree of superheat is high during conventional pull-down operation.
  • the degree of superheat is set to 30 [K].
  • Point R indicates the state of the first refrigerant after flowing out from the first evaporator 14 and before being sucked into the first compressor 10
  • point S indicates the state of the first refrigerant after being discharged from the first compressor 10. .
  • the first refrigerant follows a state change from point R to point S shown by a dashed line.
  • the degree of superheat is as high as approximately 30 [K]
  • the temperature of the first refrigerant discharged from the first compressor 10 is as high as approximately 130 [°C]
  • the temperature of the first refrigerant is as high as approximately 130 [°C]. Temperature exceeds acceptable range.
  • the first refrigerant is further cooled in the heat exchanger 12 after being cooled in the first condenser 11, even if the degree of superheat is high, the first refrigerant is discharged from the first compressor 10.
  • the state of the first refrigerant can be set to the state of point T.
  • the temperature and pressure indicated by point T are within acceptable limits.
  • the second control device 8 detects the difference between the pressure detected by the first pressure detection device 30 and the first threshold pressure, and the temperature detected by the first temperature detection device 31 and the first threshold temperature. A target evaporation temperature is determined based on one or both of the differences between. Then, the second control device 8 acquires the necessary refrigerating capacity Q based on equation (1) and the target evaporation temperature, and acquires the necessary operating frequency of the second compressor 20 based on the acquired refrigerating capacity Q. do.
  • FIG. 7 is a flowchart illustrating the flow of processing during pulldown operation by the refrigeration apparatus according to the second embodiment.
  • the first control device 7 determines whether pull-down operation is being performed.
  • the first control device 7 can determine whether the pull-down operation is being performed in the following manner. First, the first control device 7 is set with operation modes associated with each operation such as refrigeration operation and pull-down operation. If the operation mode corresponding to the pull-down operation is selected, the first control device 7 determines that the pull-down operation is being performed.
  • step S11 NO
  • the refrigeration apparatus 100 returns the process to step S11.
  • the second control device 8 controls the second compressor 20, the second expansion valve 22, etc. based on the detection results from the first pressure detection device 30 and the first temperature detection device 31, respectively. Good too.
  • the second control device 8 may perform the determination process in step S11. In this case, the second control device 8 may periodically acquire information indicating the operation mode corresponding to the operation in progress from the first control device 7, or each time the operation is started, the second control device 8 may obtain information indicating the operation mode corresponding to the operation in progress. Information indicating the corresponding driving mode may also be acquired.
  • step S11 If the pull-down operation is being performed (step S11: YES), the refrigeration apparatus 100 moves the process to step S12.
  • the processing from step S12 to step S14 is similar to the processing from step S2 to step S4. If neither the first condition nor the second condition is satisfied in step S14 (step S14: NO), the refrigeration apparatus 100 returns the process to step S11.
  • the first control device 7 or the second control device 8 determines whether the third condition is satisfied, as in the first embodiment. Good too. If the third condition is satisfied, the first control device 7 may increase the operating frequency of the first compressor 10 and operate the first compressor 10 at the increased operating frequency.
  • step S14 If both or one of the first condition and the second condition are satisfied in step S14 (step S14: YES), the refrigeration apparatus 100 moves the process to step S15.
  • the process in step S15 is similar to the process in step S5. If the operating frequency of the second compressor 20 is the maximum (step 15: YES), the first control device 7 lowers the operating frequency of the first compressor 10 in step S16, and maintains the operating frequency after the reduction. The first compressor 10 is operated, and the opening degree of the first expansion valve 13 is decreased. After the process in step S16, the refrigeration apparatus 100 returns the process to step S11. If the operating frequency of the second compressor 20 is not the maximum (step 15: NO), the refrigeration apparatus 100 moves the process to step S17. The process in step S17 is similar to the process in step S7. After the process in step S17, the refrigeration apparatus 100 returns the process to step S11.
  • the first refrigerant circuit 1 is provided with the first pressure sensing device 30 and the first temperature sensing device 31.
  • the first pressure sensing device 30 and the first temperature sensing device 31 may be provided.
  • the second control device 8 acquires the detection result from the first pressure detection device 30 directly or via the first control device 7.
  • the second control device 8 lowers the target evaporation temperature based on the first threshold pressure and the detection result of the first pressure detection device 30 when the first condition is satisfied.
  • the second control device 8 increases the operating frequency of the second compressor 20 so that the evaporation temperature of the second refrigerant in the heat exchanger 12 becomes the target evaporation temperature after the decrease.
  • the second control device 8 operates the second compressor 20 at the increased operating frequency.
  • the second control device 8 increases the operating frequency of the second compressor 20 based on the detection result of the first pressure sensing device 30 without determining the target evaporation temperature, and increases the operating frequency of the second compressor 20 at the increased operating frequency. 2 compressors 20 may be operated.
  • the second control device 8 stores the above-mentioned correspondence information that associates the pressure of the first refrigerant with the operating frequency of the second compressor 20, and based on the correspondence information, the second The operating frequency of machine 20 may be increased.
  • the first control device 7 controls the operating frequency of the first compressor 10 when the operating frequency of the second compressor 20 is maximum and the first condition is satisfied during pump-down operation. lower.
  • the first control device 7 lowers the operating frequency of the first compressor 10 when the operating frequency of the second compressor 20 is the maximum and the first condition is satisfied during the pull-down operation. and decrease the opening degree of the first expansion valve 13.
  • the first control device 7 increases the operating frequency of the first compressor 10 and performs first compression at the increased operating frequency.
  • the machine 10 may also be operated.
  • the second control device 8 acquires the detection result from the first temperature detection device 31 directly or via the first control device 7.
  • the second control device 8 lowers the target evaporation temperature based on the first threshold temperature and the detection result of the first temperature detection device 31 when the second condition is satisfied.
  • the second control device 8 increases the operating frequency of the second compressor 20 so that the evaporation temperature of the second refrigerant in the heat exchanger 12 becomes the target evaporation temperature after the decrease.
  • the second control device 8 operates the second compressor 20 at the increased operating frequency.
  • the second control device 8 increases the operating frequency of the second compressor 20 based on the detection result of the first temperature detection device 31 without determining the target evaporation temperature, and increases the operating frequency of the second compressor 20 at the increased operating frequency.
  • 2 compressors 20 may be operated.
  • the second control device 8 stores correspondence information that associates the temperature of the first refrigerant with the operating frequency of the second compressor 20, and based on the correspondence information, The operating frequency may be increased.
  • the first control device 7 controls the operating frequency of the first compressor 10 when the operating frequency of the second compressor 20 is maximum and the second condition is satisfied during pump-down operation. lower.
  • the first control device 7 lowers the operating frequency of the first compressor 10 when the operating frequency of the second compressor 20 is the maximum and the second condition is satisfied during the pull-down operation. and decrease the opening degree of the first expansion valve 13.
  • the first control device 7 increases the operating frequency of the first compressor 10 and performs first compression at the increased operating frequency.
  • the machine 10 may also be operated.
  • the second control device 8 increases the operating frequency of the second compressor 20 when both or one of the first condition and the second condition is satisfied.
  • the explanation has been given using an example in which the second compressor 20 is operated at the increased operating frequency.
  • the second control device 8 controls the second compressor 20 in order to keep the pressure and temperature of the first refrigerant within the permissible range when both or one of the first condition and the second condition are satisfied.
  • the second expansion valve 22 may be controlled instead or together with the second compressor 20.
  • Embodiment 3 the refrigeration apparatus 100 according to the third embodiment will be described in detail. Note that in the third embodiment, the same reference numerals are given to the same components as those in the first to second embodiments. Furthermore, in Embodiment 3, there are no special circumstances regarding the configuration similar to the configuration in Embodiment 1 to Embodiment 2, and the same functions as in Embodiment 1 to Embodiment 2. The explanation will be omitted as far as possible.
  • FIG. 8 is a schematic diagram showing a configuration example of a refrigeration system according to Embodiment 3.
  • the outdoor unit 3 of the refrigeration system 100 includes the second refrigerant circuit 2.
  • the refrigeration system 100 according to the third embodiment includes a third control device 9 instead of the first control device 7 and the second control device 8 described above.
  • the third control device 9 is provided in the outdoor unit 3.
  • the third control device 9 is an example of a control device.
  • the third control device 9 corresponds to the above-described first control device 7 and second control device 8 integrated.
  • the third control device 9 determines whether the first operation, which is either a pump-down operation or a pull-down operation, is being executed, and if the first operation is being executed, the second compressor 20 is operated. At this time, the third control device 9 operates the second compressor 20 so that the evaporation temperature of the second refrigerant in the heat exchanger 12 becomes the target evaporation temperature. Note that the third control device 9 acquires the detection result from the second pressure detection device 40, and acquires the evaporation temperature based on the detection result.
  • the third control device 9 also controls the evaporation temperature of the second refrigerant in the heat exchanger 12, the temperature of the second refrigerant flowing into the heat exchanger 12, or the temperature of the second refrigerant flowing out from the heat exchanger 12.
  • the target evaporation temperature is set to be lower than the temperature of the first refrigerant flowing into the heat exchanger 12.
  • the third control device 9 acquires detection results from each of the first pressure sensing device 30 and the first temperature sensing device 31.
  • the third control device 9 may acquire the temperature of the first refrigerant flowing into the heat exchanger 12 based on the detection results of both or one of the first pressure detection device 30 and the first temperature detection device 31.
  • the third control device 9 may acquire the temperature of the first refrigerant flowing into the heat exchanger 12 from the detection result of the first temperature acquisition device described above.
  • the third control device 9 may acquire the temperature of the first refrigerant flowing into the heat exchanger 12 from the detection result of the second temperature acquisition device or the second pressure detection device 40.
  • the third control device 9 may acquire the temperature of the first refrigerant flowing out from the heat exchanger 12 from the detection result of the third temperature acquisition device or the second pressure detection device 40.
  • the third control device 9 When both or one of the first condition and the second condition are satisfied, the third control device 9 performs the second compression, similar to the second control device 8 of the first and second embodiments.
  • the operating frequency of the compressor 20 is increased, and the second compressor 20 is operated at the increased operating frequency. Even if the operating frequency of the second compressor 20 is increased to the maximum during pump-down operation, the third control device 9 is configured to control the operation if both or one of the first condition and the second condition are satisfied. Similar to the first control device 7 of the first to second embodiments, the operating frequency of the first compressor 10 is lowered. Even if the operating frequency of the second compressor 20 is increased to the maximum during pull-down operation, the third control device 9 controls the operation according to the embodiment if both or one of the first condition and the second condition is satisfied.
  • the operating frequency of the first compressor 10 is lowered and the opening degree of the first expansion valve 13 is decreased.
  • the third control device 9 increases the operating frequency of the first compressor 10, similarly to the first control device 7 of the first and second embodiments.
  • the first compressor 10 is operated at the later operating frequency.
  • the third control device 9 controls the second expansion valve 22 in order to bring the pressure and temperature of the first refrigerant within the permissible range when both or one of the first condition and the second condition are satisfied. May be controlled.
  • the first refrigerant circuit 1 of the third embodiment may be provided with only one of the first pressure sensing device 30 and the first temperature sensing device 31.
  • the processing of the refrigeration system 100 when only the first pressure sensing device 30 is provided in the first refrigerant circuit 1 will be described below.
  • the third control device 9 increases the operating frequency of the second compressor 20, similarly to the second control device 8 of the first and second embodiments.
  • the second compressor 20 is operated at the later operating frequency. If the first condition is satisfied even if the operating frequency of the second compressor 20 is increased to the maximum, the third control device 9 operates in accordance with the first control device 7 of the first to second embodiments. Similarly, the operating frequency of the first compressor 10 is lowered.
  • the third control device 9 controls the first condition according to the first to second embodiments. Similar to the control device 7, the operating frequency of the first compressor 10 is lowered, and the opening degree of the first expansion valve 13 is reduced. When the pressure detected by the first pressure detection device 30 is less than the second threshold pressure, the third control device 9 increases the operating frequency of the first compressor 10 and performs first compression at the increased operating frequency. The machine 10 may also be operated.
  • the third control device 9 acquires the detection result from the first temperature detection device 31.
  • the third control device 9 increases the operating frequency of the second compressor 20, similarly to the second control device 8 of the first and second embodiments.
  • the second compressor 20 is operated at the later operating frequency. If the second condition is satisfied even if the operating frequency of the second compressor 20 is increased to the maximum, the third control device 9 performs the same operation as the first control device 7 of the first to second embodiments. Similarly, the operating frequency of the first compressor 10 is lowered.
  • the third control device 9 controls the first control device of the first to second embodiments. Similar to the control device 7, the operating frequency of the first compressor 10 is lowered, and the opening degree of the first expansion valve 13 is reduced. When the temperature detected by the first temperature detection device 31 is lower than the second threshold temperature, the third control device 9 increases the operating frequency of the first compressor 10 and performs first compression at the increased operating frequency. The machine 10 may also be operated.
  • FIG. 9 is a block diagram illustrating the hardware configuration of the third control device in the third embodiment.
  • the third control device 9 includes, for example, a third processor 91, a third memory 92, the first input interface circuit 74, the first output interface circuit 75, and the It can be configured by a second output interface circuit 84.
  • the third processor 91 is a CPU, an MPU, or the like.
  • the third memory 92 is a ROM, RAM, or the like.
  • the function of the third controller 9 to perform processing based on the detection results etc. from each of the first pressure sensing device 30 and the first temperature sensing device 31 is stored in the third memory 92 by the third processor 91. This can be achieved by reading and executing various programs and data.
  • the control function of the first compressor 10, the first expansion valve 13, etc. by the third control device 9 is performed by the first output interface circuit 75 connected by wire to the first compressor 10, the first expansion valve 13, etc. This can be realized by the processor 91 and the third memory 92.
  • the third control device 9 may include a first wireless communication interface circuit instead of the first output interface circuit 75, and may control the first compressor 10, the first expansion valve 13, etc. by wireless communication.
  • the control function of the second compressor 20, the second expansion valve 22, etc. by the third control device 9 is performed by a second output interface circuit 84 connected by wire to the second compressor 20, a third processor 91, and a third memory. 92.
  • the third control device 9 may include a second wireless communication interface circuit instead of the second output interface circuit 84, and may control the second compressor 20, the second expansion valve 22, etc. by wireless communication.
  • all or part of the functions of the third control device 9 may be realized by dedicated hardware such as a CPLD or FPGA.
  • FIG. 5 The flow of processing during pump-down operation by the refrigeration apparatus 100 in the third embodiment is illustrated by FIG. 5.
  • each of the first control device 7 and the second control device 8 is replaced with the third control device 9. Further, processing related to communication between the first control device 7 and the second control device 8 is omitted. This will be explained in detail below.
  • step S1 the third control device 9 determines whether pump down operation is being performed.
  • the method of determining whether or not the pump-down operation is to be performed by the third control device 9 is the same as the method of determining by the first control device 7 described in the first embodiment.
  • step S1: NO the refrigeration apparatus 100 returns the process to step S1.
  • the third control device 9 controls the second compressor 20, the second expansion valve 22, etc. based on the detection results from the first pressure detection device 30 and the first temperature detection device 31, respectively. Good too. If the pump-down operation is being performed (step S1: YES), the third control device 9 determines whether the second compressor 20 is operating in step S2. If the second compressor 20 is operating (step S2: YES), the refrigeration system 100 moves the process to step S4. If the second compressor 20 is not operating (step S2: NO), the third control device 9 operates the second compressor 20 in step S3.
  • step S4 the third control device 9 determines whether both or one of the first condition and the second condition described above are satisfied. If both the first condition and the second condition are not satisfied (step S4: NO), the refrigeration apparatus 100 returns the process to step S1. When the process returns from step S4 to step S1, the third control device 9 may determine whether the third condition is satisfied. If the third condition is satisfied, the third control device 9 may increase the operating frequency of the first compressor 10 and operate the first compressor 10 at the increased operating frequency.
  • step S4 determines whether both or one of the first condition and the second condition are satisfied (step S4: YES). If both or one of the first condition and the second condition are satisfied (step S4: YES), the third control device 9 determines whether the operating frequency of the second compressor 20 is at the maximum or not in step S5. Determine whether If the operating frequency of the second compressor 20 is the maximum (step S5: YES), the third control device 9 lowers the operating frequency of the first compressor 10 in step S6, and maintains the operating frequency after the reduction. The first compressor 10 is operated. After the process in step S6, the refrigeration apparatus 100 returns the process to step S1. If the operating frequency of the second compressor 20 is not the maximum (step S5: NO), the third control device 9 increases the operating frequency of the second compressor 20 in step S7, and at the increased operating frequency. The second compressor 20 is operated. After the process in step S7, the refrigeration apparatus 100 returns the process to step S1.
  • FIG. 7 The flow of processing during pulldown operation by the refrigeration apparatus 100 in the third embodiment is illustrated by FIG. 7. However, in the third embodiment, in the above description regarding FIG. 7, each of the first control device 7 and the second control device 8 is replaced with the third control device 9. Further, processing related to communication between the first control device 7 and the second control device 8 is omitted. This will be explained in detail below.
  • step S11 the third control device 9 determines whether pull-down operation is being performed.
  • the method of determining whether or not to perform the pull-down operation by the third control device 9 is the same as the method of determining by the first control device 7 described in the second embodiment.
  • step S11: NO the refrigeration apparatus 100 returns the process to step S11.
  • the third control device 9 controls the second compressor 20, the second expansion valve 22, etc. based on the detection results from the first pressure detection device 30 and the first temperature detection device 31, respectively. Good too.
  • step S11: YES the refrigeration apparatus 100 moves the process to step S12.
  • the processing from step S12 to step S14 is similar to the processing from step S2 to step S4 in the third embodiment.
  • step S14 If neither the first condition nor the second condition is satisfied in step S14 (step S14: NO), the refrigeration apparatus 100 returns the process to step S11.
  • the third control device 9 may determine whether the third condition is satisfied. If the third condition is satisfied, the third control device 9 may increase the operating frequency of the first compressor 10 and operate the first compressor 10 at the increased operating frequency.
  • step S14 determines whether the operating frequency of the second compressor 20 is the maximum or not. Determine whether If the operating frequency of the second compressor 20 is the maximum (step 15: YES), the third control device 9 lowers the operating frequency of the first compressor 10 in step S16, and maintains the operating frequency after the reduction. The first compressor 10 is operated, and the opening degree of the first expansion valve 13 is decreased. After the process in step S16, the refrigeration apparatus 100 returns the process to step S11. If the operating frequency of the second compressor 20 is not the maximum (step 15: NO), the refrigeration apparatus 100 moves the process to step S17. The process in step S17 is similar to the process in step S7 in the third embodiment. After the process in step S17, the refrigeration apparatus 100 returns the process to step S11.
  • Refrigeration apparatus 100 includes a first refrigerant circuit 1, a second refrigerant circuit 2, and a control device.
  • the first refrigerant circuit 1 includes a first compressor 10 , a first condenser 11 , a heat exchanger 12 , a first expansion valve 13 , and a first evaporator 14 .
  • the first refrigerant circuit 1 circulates the first refrigerant.
  • the second refrigerant circuit 2 includes a second compressor 20 and a heat exchanger 12.
  • the second refrigerant circuit 2 circulates the second refrigerant.
  • the control device causes the first compressor 10 to perform a first operation, which is either a pump-down operation or a pull-down operation.
  • the pump-down operation is an operation in which the first refrigerant is recovered from the discharge side of the first compressor 10 to the first expansion valve 13.
  • the pull-down operation is an operation in which the temperature of the object that exchanges heat with the first refrigerant in the first evaporator 14 is lowered to a target value when the temperature of the object is equal to or higher than a specified value.
  • the heat exchanger 12 functions as a condenser in the first refrigerant circuit 1 and as an evaporator in the second refrigerant circuit 2, and performs heat exchange between the first refrigerant and the second refrigerant.
  • the control device When causing the first compressor 10 to perform the first operation, the control device operates the second compressor 20 so that the evaporation temperature of the second refrigerant in the heat exchanger 12 becomes the target evaporation temperature.
  • the target evaporation temperature is set so that the temperature of the second refrigerant flowing into the heat exchanger 12 is lower than the temperature of the first refrigerant flowing into the heat exchanger 12.
  • the control device operates the second compressor 20 so that the evaporation temperature of the second refrigerant in the heat exchanger 12 becomes the target evaporation temperature.
  • the target evaporation temperature is set so that the temperature of the second refrigerant flowing into the heat exchanger 12 is lower than the temperature of the first refrigerant flowing into the heat exchanger 12. Therefore, the first refrigerant is cooled by heat exchange with the second refrigerant in the heat exchanger 12. Therefore, the refrigeration apparatus 100 according to Embodiments 1 to 3 can suppress an increase in both or one of the pressure and temperature of the first refrigerant.
  • the refrigeration apparatus 100 further includes a first pressure detection device 30 that detects the pressure of the first refrigerant discharged from the first compressor 10.
  • the control device determines the target evaporation temperature based on the detection result by the first pressure detection device 30 when executing the first operation. Thereby, the control device can accurately obtain the target evaporation temperature necessary for ensuring that both or one of the pressure and temperature of the first refrigerant does not exceed the allowable range.
  • Embodiments 1 to 3 perform the target operation when the pressure detected by the first pressure sensing device 30 is equal to or higher than a predetermined first threshold pressure during execution of the first operation. Reduces evaporation temperature. As a result, the condensation temperature of the first refrigerant in the heat exchanger 12 decreases. Therefore, the refrigeration apparatus 100 can suppress an increase in both or one of the pressure and temperature of the first refrigerant discharged from the first compressor 10.
  • the refrigeration apparatus 100 further includes a first pressure detection device 30 that detects the pressure of the first refrigerant discharged from the first compressor 10.
  • the control device operates the second compressor 20 based on the detection result by the first pressure detection device 30 when performing the first operation.
  • the operation of the second compressor 20 allows the second refrigerant to cool the first refrigerant in the heat exchanger 12 .
  • the control device controls the second compressor 20 based on the detection result by the first pressure detection device 30 to suppress increases in both or one of the pressure and temperature of the first refrigerant discharged from the first compressor 10 with high precision. can be done.
  • the control device performs the first operation when the pressure detected by the first pressure sensing device 30 is equal to or higher than a predetermined first threshold pressure during execution of the first operation. 2.
  • the operating frequency of the compressor 20 is increased.
  • the evaporation temperature of the second refrigerant in the heat exchanger 12 decreases, and the condensation temperature of the first refrigerant also decreases. Therefore, the refrigeration apparatus 100 can suppress the pressure and/or temperature of the first refrigerant discharged from the first compressor 10 from rising beyond the allowable range.
  • the control device when the pressure detected by the first pressure sensing device 30 is lower than the second threshold pressure which is equal to or lower than the first threshold pressure during execution of the first operation, , the operating frequency of the first compressor 10 is increased.
  • the refrigeration system 100 can quickly perform the first operation by increasing the operating frequency of the first compressor 10 while the pressure of the first refrigerant discharged from the first compressor 10 is within the allowable range. can. That is, the refrigeration apparatus 100 can quickly recover the first refrigerant during pump-down operation, and can quickly change the temperature of the object to the set temperature during pull-down operation.
  • the refrigeration apparatus 100 further includes a first temperature detection device 31 that detects the temperature of the first refrigerant discharged from the first compressor 10.
  • the control device determines the target evaporation temperature based on the detection result by the first temperature detection device 31 when executing the first operation. Thereby, the control device can accurately obtain the target evaporation temperature necessary for ensuring that both or one of the pressure and temperature of the first refrigerant does not exceed the allowable range.
  • Embodiments 1 to 3 perform the target operation when the temperature detected by the first temperature detection device 31 is equal to or higher than a predetermined first threshold temperature during execution of the first operation. Reduces evaporation temperature. As a result, the condensation temperature of the first refrigerant in the heat exchanger 12 decreases. Therefore, the refrigeration apparatus 100 can suppress an increase in both or one of the pressure and temperature of the first refrigerant discharged from the first compressor 10.
  • the refrigeration apparatus 100 further includes a first temperature detection device 31 that detects the temperature of the first refrigerant discharged from the first compressor 10.
  • the control device operates the second compressor 20 based on the detection result by the first temperature detection device 31 when performing the first operation.
  • the operation of the second compressor 20 allows the second refrigerant to cool the first refrigerant in the heat exchanger 12 .
  • the control device controls the second compressor 20 based on the detection result by the first temperature detection device 31 to suppress increases in both or one of the pressure and temperature of the first refrigerant discharged from the first compressor 10 with high precision. can be done.
  • the control device in Embodiments 1 to 3 performs the first operation when the temperature detected by the first temperature detection device 31 is equal to or higher than a predetermined first threshold temperature during execution of the first operation. 2.
  • the operating frequency of the compressor 20 is increased.
  • the evaporation temperature of the second refrigerant in the heat exchanger 12 decreases, and the condensation temperature of the first refrigerant also decreases. Therefore, the refrigeration apparatus 100 can suppress the pressure and/or temperature of the first refrigerant discharged from the first compressor 10 from rising beyond the allowable range.
  • the operating frequency of the first compressor 10 is increased.
  • the refrigeration system 100 can quickly perform the first operation by increasing the operating frequency of the first compressor 10 while the temperature of the first refrigerant discharged from the first compressor 10 is within the allowable range. can.
  • the second refrigerant circuit 2 in Embodiments 1 to 3 further includes a second expansion valve 22 that expands the second refrigerant flowing into the heat exchanger 12.
  • the control device controls the second expansion valve 22 so that the evaporation temperature of the second refrigerant in the heat exchanger 12 becomes the target evaporation temperature.
  • the refrigeration apparatus 100 can efficiently adjust the temperature of the second refrigerant flowing into the heat exchanger 12. Therefore, the refrigeration system 100 can efficiently suppress increases in pressure and temperature of the first refrigerant.
  • the outdoor unit 3 of the refrigeration system 100 is provided in the first refrigerant circuit 1 through which the first refrigerant circulates, and is connected to the first expansion valve 13 and the first evaporator 14.
  • the outdoor unit 3 includes a first compressor 10, a first condenser 11, a second refrigerant circuit 2, a heat exchanger 12, and a control device.
  • the first compressor 10 compresses the first refrigerant.
  • the first condenser 11 condenses the first refrigerant.
  • the second refrigerant circuit 2 includes a second compressor 20 and circulates the second refrigerant.
  • the heat exchanger 12 is provided in the first refrigerant circuit 1 and the second refrigerant circuit 2 to exchange heat between the first refrigerant and the second refrigerant.
  • the control device causes the first compressor 10 to perform a first operation, which is either a pump-down operation or a pull-down operation.
  • the heat exchanger 12 functions as a condenser in the first refrigerant circuit 1 and as an evaporator in the second refrigerant circuit 2.
  • the control device operates the second compressor 20 so that the evaporation temperature of the second refrigerant in the heat exchanger 12 becomes the target evaporation temperature.
  • the control device operates the second compressor 20 so that the evaporation temperature of the second refrigerant becomes the target evaporation temperature in the heat exchanger 12, so that the first refrigerant It is cooled in the vessel 12 by heat exchange with the second refrigerant. Therefore, the outdoor unit 3 according to the third embodiment can suppress an increase in both or one of the pressure and temperature of the first refrigerant.
  • the third control device 9 in the third embodiment corresponds to the first control device 7 and the second control device 8 in the first to second embodiments, and is similar to the first control device 7 and the second control device 8 in the first embodiment. It has each function of the second control device 8. Therefore, in the third control device 9 in the third embodiment, processing corresponding to communication processing between the first control device 7 and the second control device 8 is not necessary, and the amount of processing can be reduced. Furthermore, in the third embodiment, it is possible to suppress the occurrence of communication problems such as transmission errors or communication delays that may occur during communication. Further, since the third control device 9 acquires detection results from the first pressure detection device 30 and the first temperature detection device 31 and controls both or one of the first compressor 10 and the second compressor 20, the control This enables faster response times.
  • the refrigeration apparatus 100 can be made more compact. As a result, the length of the second refrigerant pipe 6 in the second refrigerant circuit 2 can be shortened, and as a result, the pressure loss of the second refrigerant can be suppressed. Therefore, the third control device 9 can improve the accuracy of the adjustment process of the evaporation temperature of the second refrigerant. Therefore, the refrigeration system 100 according to the third embodiment can accurately lower the condensation temperature of the first refrigerant that exchanges heat with the second refrigerant in the heat exchanger 12.
  • Embodiment 4 the refrigeration apparatus 100 according to the fourth embodiment will be described in detail. Note that in the fourth embodiment, the same reference numerals are given to the same components as those in the first to third embodiments. Furthermore, in Embodiment 4, there are no special circumstances regarding the configuration similar to the configuration in Embodiment 1 to Embodiment 3, and the same functions as in Embodiment 1 to Embodiment 3. The explanation will be omitted as far as possible.
  • FIG. 10 is a schematic diagram showing a configuration example of the second refrigerant circuit in Embodiment 4.
  • the second refrigerant circuit 2 in the fourth embodiment is provided with a bypass circuit 2A.
  • the bypass circuit 2A has an on-off valve 23.
  • the bypass circuit 2A is connected to the second refrigerant pipe 6 on the side from which the second refrigerant is discharged from the second compressor 20, and is also connected to the second refrigerant pipe 6 on the upstream side of the heat exchanger 12.
  • the bypass circuit 2A may be connected to the second refrigerant pipe 6 on the downstream side of the heat exchanger 12 instead of the second refrigerant pipe 6 on the upstream side of the heat exchanger 12.
  • the configuration of the refrigeration apparatus 100 according to the fourth embodiment is the same as that of the first to third embodiments, except that the bypass circuit 2A having the on-off valve 23 is provided in the second refrigerant circuit 2. Or as exemplified by FIG.
  • the bypass circuit 2A and the on-off valve 23 suppress the following liquid return.
  • Liquid return is when the second refrigerant does not absorb heat from the first refrigerant in the heat exchanger 12 and the degree of superheat of the second refrigerant flowing out from the heat exchanger 12 is less than a predetermined value. This refers to the flow of the liquid second refrigerant into the machine 20.
  • Liquid backlash can occur in each of the following two cases. In the first case, the temperature of the first refrigerant flowing into the heat exchanger 12 is equal to or higher than the temperature of the second refrigerant flowing into the heat exchanger 12, and the temperature of the first refrigerant and the second refrigerant are different.
  • the second case refers to a case where the temperature difference between the refrigerant temperature and the refrigerant temperature is less than or equal to a predetermined threshold temperature difference.
  • the threshold temperature difference is, for example, 5 [° C.].
  • the second case refers to a case where the temperature of the first refrigerant flowing into the heat exchanger 12 is lower than the temperature of the second refrigerant flowing into the heat exchanger 12.
  • the control device controls the temperature of the first refrigerant flowing into the heat exchanger 12 to be equal to or higher than the temperature of the second refrigerant flowing into the heat exchanger 12, and the temperature of the first refrigerant.
  • the on-off valve 23 is controlled to be in the open state.
  • the control device controls the on-off valve. 23 is controlled to be in an open state. Thereby, liquid return to the second compressor 20 is suppressed.
  • control device is the second control device 8 or the third control device 9.
  • the temperature of the first refrigerant flowing into the heat exchanger 12 is determined by the detection result of both or one of the first pressure detection device 30 and the first temperature detection device 31 described above, or the detection result of the first temperature acquisition device described above. Obtained from the detection results.
  • the temperature of the second refrigerant flowing into the heat exchanger 12 is obtained from the detection results of the second pressure detection device 40, the second temperature acquisition device, etc. described above.
  • First refrigerant circuit 1. First refrigerant circuit, 2. Second refrigerant circuit, 2A bypass circuit, 3. Outdoor unit, 4. Indoor unit, 5. First refrigerant piping, 6. Second refrigerant piping, 7. First control device, 8. Second control device, 9. 3 control device, 10 first compressor, 11 first condenser, 12 heat exchanger, 13 first expansion valve, 14 first evaporator, 20 second compressor, 21 second condenser, 22 second expansion valve , 23 on-off valve, 30 first pressure sensing device, 31 first temperature sensing device, 40 second pressure sensing device, 70 first bus, 71 first processor, 72 first memory, 73 first communication interface circuit, 74 first 1 input interface circuit, 75 first output interface circuit, 80 second bus, 81 second processor, 82 second memory, 83 second communication interface circuit, 84 second output interface circuit, 90 third bus, 91 third processor , 92 Third memory, 100 Refrigeration device.

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

Abstract

La présente invention concerne un appareil de réfrigération (100) qui comprend : un premier circuit de fluide frigorigène (1) ; un second circuit de fluide frigorigène (2) ; et des dispositifs de commande (7, 8). Le premier circuit de fluide frigorigène (1) fait circuler un premier fluide frigorigène et comprend un premier compresseur (10), un premier condenseur (11), un échangeur de chaleur (12), un premier détendeur (13) et un premier évaporateur (14). Le second circuit de fluide frigorigène (2) fait circuler un second fluide frigorigène et comprend un second compresseur (20) et l'échangeur de chaleur (12). Le dispositif de commande (7) amène le premier compresseur (10) à exécuter une première opération qui est une opération de pompage vers le bas ou une opération d'abaissement. L'échangeur de chaleur (12) fonctionne comme un condenseur dans le premier circuit de fluide frigorigène (1) et fonctionne comme un évaporateur dans le second circuit de fluide frigorigène (2). Lorsque le premier compresseur (10) est amené à exécuter la première opération, le dispositif de commande (8) amène le second compresseur (20) à fonctionner de sorte que la température d'évaporation du second fluide frigorigène dans l'échangeur de chaleur (12) atteigne une température d'évaporation cible. La température d'évaporation cible est réglée de sorte que la température du second fluide frigorigène s'écoulant dans l'échangeur de chaleur (12) devienne inférieure à la température du premier fluide frigorigène s'écoulant dans l'échangeur de chaleur (12).
PCT/JP2022/012179 2022-03-17 2022-03-17 Appareil de réfrigération et unité extérieure d'appareil de réfrigération WO2023175821A1 (fr)

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PCT/JP2022/012179 WO2023175821A1 (fr) 2022-03-17 2022-03-17 Appareil de réfrigération et unité extérieure d'appareil de réfrigération
JP2024508211A JPWO2023176870A1 (fr) 2022-03-17 2023-03-15
PCT/JP2023/010011 WO2023176870A1 (fr) 2022-03-17 2023-03-15 Unité extérieure pour dispositif de réfrigération et dispositif de réfrigération

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PCT/JP2023/010011 WO2023176870A1 (fr) 2022-03-17 2023-03-15 Unité extérieure pour dispositif de réfrigération et dispositif de réfrigération

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02192546A (ja) * 1989-01-20 1990-07-30 Daikin Ind Ltd 二元冷凍機の高圧制御装置
JP2000105012A (ja) * 1998-09-30 2000-04-11 Daikin Ind Ltd 冷凍装置
JP2000274849A (ja) * 1999-03-23 2000-10-06 Daikin Ind Ltd 二元冷凍装置
WO2014024837A1 (fr) * 2012-08-06 2014-02-13 三菱電機株式会社 Équipement frigorifique en cascade
WO2014038028A1 (fr) * 2012-09-06 2014-03-13 三菱電機株式会社 Dispositif de réfrigération
JP2014095514A (ja) * 2012-11-09 2014-05-22 Panasonic Corp 冷凍装置
WO2017175299A1 (fr) * 2016-04-05 2017-10-12 三菱電機株式会社 Dispositif à cycle frigorifique

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117222853A (zh) * 2021-04-21 2023-12-12 三菱电机株式会社 二元制冷循环装置
CN113776215A (zh) * 2021-09-18 2021-12-10 青岛科技大学 一种应用于复叠制冷或热泵系统的循环系统及过冷方法

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02192546A (ja) * 1989-01-20 1990-07-30 Daikin Ind Ltd 二元冷凍機の高圧制御装置
JP2000105012A (ja) * 1998-09-30 2000-04-11 Daikin Ind Ltd 冷凍装置
JP2000274849A (ja) * 1999-03-23 2000-10-06 Daikin Ind Ltd 二元冷凍装置
WO2014024837A1 (fr) * 2012-08-06 2014-02-13 三菱電機株式会社 Équipement frigorifique en cascade
WO2014038028A1 (fr) * 2012-09-06 2014-03-13 三菱電機株式会社 Dispositif de réfrigération
JP2014095514A (ja) * 2012-11-09 2014-05-22 Panasonic Corp 冷凍装置
WO2017175299A1 (fr) * 2016-04-05 2017-10-12 三菱電機株式会社 Dispositif à cycle frigorifique

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