WO2024111097A1 - Dispositif à cycle frigorifique - Google Patents

Dispositif à cycle frigorifique Download PDF

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Publication number
WO2024111097A1
WO2024111097A1 PCT/JP2022/043416 JP2022043416W WO2024111097A1 WO 2024111097 A1 WO2024111097 A1 WO 2024111097A1 JP 2022043416 W JP2022043416 W JP 2022043416W WO 2024111097 A1 WO2024111097 A1 WO 2024111097A1
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WO
WIPO (PCT)
Prior art keywords
flow rate
refrigerant
oil return
compressor
return path
Prior art date
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PCT/JP2022/043416
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English (en)
Japanese (ja)
Inventor
亮 築山
Original Assignee
三菱電機株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to PCT/JP2022/043416 priority Critical patent/WO2024111097A1/fr
Publication of WO2024111097A1 publication Critical patent/WO2024111097A1/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

Definitions

  • This disclosure relates to a refrigeration cycle device.
  • Patent Document 1 discloses an air conditioning device with an oil return line. One end of this oil return line is connected to an oil separator, and the other end is connected to a refrigerant pipe that runs from the evaporator to the compressor.
  • This disclosure is made to explain an embodiment that solves the problems described above, and its purpose is to provide a refrigeration cycle device that can appropriately return refrigerant oil to the compressor while avoiding a decrease in COP.
  • the present disclosure relates to a refrigeration cycle device.
  • the refrigeration cycle device includes a compressor, an oil separator, a first heat exchanger, an expansion valve, and a second heat exchanger.
  • the compressor, the oil separator, the first heat exchanger, the expansion valve, and the second heat exchanger form a refrigerant circuit in which a refrigerant circulates.
  • the refrigeration cycle device further includes an oil return path that returns refrigeration oil from the oil separator to the suction section of the compressor, a flow rate adjustment mechanism disposed in the oil return path, and a refrigerant detection device that detects the refrigerant flowing in the oil return path.
  • the flow rate adjustment mechanism controls the flow rate of a fluid passing through the oil return path according to the output of the refrigerant detection device.
  • the refrigeration cycle device disclosed herein reduces the flow rate of fluid passing through the oil return path when there is a risk of refrigerant being mixed into the oil return path, allowing refrigeration oil to be appropriately returned to the compressor while avoiding a drop in COP.
  • FIG. 1 is a diagram showing a configuration of a refrigeration cycle device according to a first embodiment
  • 5 is a flowchart for explaining control of a flow rate adjusting mechanism in the first embodiment
  • 10 is a flowchart for explaining control of a flow rate adjusting mechanism in the second embodiment.
  • FIG. 11 is a diagram showing the configuration of a refrigeration cycle device according to a third embodiment.
  • FIG. 13 is a diagram showing the configuration of a refrigeration cycle device according to a fourth embodiment.
  • FIG. 13 is a diagram showing the configuration of a refrigeration cycle device according to a fifth embodiment.
  • FIG. 13 is a diagram showing the configuration of a refrigeration cycle device of a seventh embodiment.
  • Embodiment 1. 1 is a diagram showing the configuration of a refrigeration cycle apparatus according to a first embodiment.
  • the refrigeration cycle apparatus 1001 includes a compressor 10, an oil separator 11, a heat exchanger 13, an expansion valve 14, a heat exchanger 15, and a control device 600.
  • the compressor 10, the oil separator 11, the heat exchanger 13, the expansion valve 14, and the heat exchanger 15 constitute a refrigerant circuit C1 in which a refrigerant circulates.
  • the heat exchanger 13 functions as a condenser
  • the heat exchanger 15 functions as an evaporator.
  • the refrigeration cycle device 1001 further includes an oil return path RP that returns refrigeration oil from the oil discharge section of the oil separator 11 to the suction section of the compressor 10, a flow rate adjustment mechanism 16 arranged in the oil return path RP, a refrigerant detection device 17 that detects that refrigerant has flowed through the oil return path RP, and a control device 600 that controls the flow rate adjustment mechanism 16 in response to the output of the refrigerant detection device 17.
  • the refrigeration oil passes through the oil return path RP and is returned to the suction section of the compressor 10.
  • the flow rate adjustment mechanism 16 controls the flow rate of the fluid (refrigeration oil and refrigerant) passing through the oil return path RP in response to commands from the control device 600.
  • a receiver may be provided between the heat exchanger 13 and the expansion valve 14. Also, although not shown, the heat exchanger 13 and the heat exchanger 15 are each provided with a fan.
  • the control device 600 is composed of a CPU (Central Processing Unit) 601, memory 602 (ROM (Read Only Memory) and RAM (Random Access Memory)), an input/output buffer (not shown), etc.
  • the CPU 601 deploys a program stored in the ROM into the RAM etc. and executes it.
  • the program stored in the ROM is a program in which the processing procedures of the control device 600 are written.
  • the control device 600 controls each device in the refrigeration cycle device in accordance with these programs. This control is not limited to processing by software, but can also be processed by dedicated hardware (electronic circuits).
  • the control device 600 may be distributed between the indoor unit and the outdoor unit and connected via communication.
  • FIG. 2 is a flow chart for explaining the control of the flow rate adjustment mechanism in the first embodiment.
  • the control device 600 determines whether or not refrigerant is flowing in the oil return path RP, or whether or not a certain amount of refrigerant is flowing, based on the output of the refrigerant detection device 17.
  • bypassed refrigerant refrigerant
  • the control device 600 controls the flow rate adjustment mechanism 16 to reduce the flow rate of the fluid flowing through the oil return path RP in step S2.
  • control device 600 controls the flow rate adjustment mechanism 16 to increase the flow rate of the fluid flowing through the oil return path RP in step S3.
  • Embodiment 2 In the first embodiment, while the refrigeration cycle device is in operation, the amount of refrigerant flowing through the oil return path RP is constantly monitored, and the flow rate is controlled by the flow rate adjustment mechanism 16.
  • the flow rate adjustment mechanism 16 also has moving parts, and it is advantageous in terms of the life of the device to move the moving parts as few times as possible.
  • control shown in Figure 2 is executed only in situations where refrigerant is likely to flow into the oil return path RP.
  • FIG. 3 is a flowchart for explaining the control of the flow rate adjustment mechanism in the second embodiment.
  • the control device 600 determines whether an execution condition for determining whether or not to execute the flow rate adjustment control is satisfied.
  • control device 600 determines that the execution condition of step S11 is met when the operating frequency of the compressor 10 is lower than the judgment frequency.
  • the judgment frequency can be set to, for example, half the upper limit of the operating frequency of the compressor.
  • the operating frequency of the compressor 10 When the operating frequency of the compressor 10 is low, the amount of refrigeration oil discharged from the compressor 10 decreases. As the amount of refrigeration oil in the oil separator 11 decreases, the refrigerant is more likely to return to the oil return path RP. On the other hand, when there is a lot of refrigeration oil in the oil separator 11, the refrigeration oil mainly flows through the oil return path RP, so a decrease in COP due to the presence of the oil return path is unlikely to occur. Therefore, as described above, the operating frequency of the compressor is used to determine whether or not to perform flow rate adjustment control.
  • control device 600 may determine that the execution conditions for step S11 are met when the pressure difference between the suction section and the discharge section of the compressor 10 is smaller than a judgment threshold value.
  • the judgment threshold value can be set to half the maximum value of the pressure difference.
  • the diameter of the fluid passage restriction portion of the flow rate adjustment mechanism is the same, the greater the differential pressure, the greater the amount of fluid passing through the oil return path RP, making it easier for the refrigerant to return. Therefore, as described above, it may be possible to determine whether or not to perform flow rate adjustment control based on the magnitude of the differential pressure.
  • control device 600 sets the flow rate of the flow rate adjustment mechanism 16 to the standard value. This reduces the number of times the moving parts of the flow rate adjustment mechanism 16 move, which is advantageous in terms of product life.
  • step S12 the control device 600 determines whether refrigerant is flowing through the oil return path RP, or whether a certain amount of refrigerant or more is flowing, based on the output of the refrigerant detection device 17.
  • control device 600 controls the flow rate adjustment mechanism 16 to reduce the flow rate of the fluid flowing through the oil return path RP in step S13.
  • control device 600 controls the flow rate adjustment mechanism 16 to increase the flow rate of the fluid flowing through the oil return path RP in step S14.
  • Embodiment 3 a first specific example of the refrigerant detection device described in the first embodiment will be described.
  • FIG. 4 is a diagram showing the configuration of a refrigeration cycle apparatus of embodiment 3.
  • the refrigerant detection device 17 includes a temperature sensor 17A arranged upstream of the flow rate adjustment mechanism 16 in the oil return path RP, and a temperature sensor 17B arranged downstream of the flow rate adjustment mechanism 16 in the oil return path RP.
  • the configuration of the other parts of the refrigeration cycle apparatus 1002 is similar to that of the refrigeration cycle apparatus 1001 in FIG. 1, and description thereof will not be repeated.
  • the refrigeration cycle apparatuses in FIG. 4 and subsequent figures also include a control device 600, but this is not shown in the drawings.
  • Figure 5 is a p-h diagram to explain the state when the refrigerant passes through the oil return path in embodiment 3.
  • the refrigerant discharged from the compressor 10 releases heat to the atmosphere in the heat exchanger 13 and condenses (P2-P3).
  • the condensed refrigerant is adiabatically expanded in the expansion valve 14 and reduced in pressure (P3-P4).
  • the reduced-pressure refrigerant evaporates in the heat exchanger 15 and becomes gas refrigerant, which returns to the compressor 10 (P4-P1).
  • the refrigerant drawn into the compressor 10 is compressed and discharged as high-temperature, high-pressure gas refrigerant (P1-P2).
  • the pressure is reduced by the flow rate adjustment mechanism 16, causing the refrigerant temperature to drop.
  • the detected temperatures of the upstream temperature sensor 17A and the downstream temperature sensor 17B differ.
  • the flow rate adjustment mechanism 16 reduces the flow rate compared to when the temperature difference is smaller than the judgment threshold.
  • control device 600 determines that refrigerant is passing through the oil return path RP.
  • the upstream temperature sensor 17A is shown to be installed upstream of the flow rate adjustment mechanism of the oil return circuit, but it may be installed in another location as long as it is a location where a temperature close to the discharge temperature of the compressor 10 can be measured.
  • the temperature sensor 17A may be installed between the compressor 10 and the oil separator 11, or between the oil separator 11 and the heat exchanger 13.
  • FIG. 6 is a diagram showing the configuration of a refrigeration cycle device of the fourth embodiment.
  • the oil return path RP merges with the refrigerant circuit C1 at a junction MP between the heat exchanger 15 in the refrigerant circuit C1 and the suction port of the compressor 10.
  • the refrigerant detection device 17 includes a temperature sensor 17C arranged upstream of the junction MP in the refrigerant circuit C1, and a temperature sensor 17D arranged downstream of the junction MP in the oil return path RP.
  • the configuration of the other parts of the refrigeration cycle device 1003 is similar to that of the refrigeration cycle device 1001 in FIG. 1, and the description will not be repeated.
  • temperature sensors 17C and 17D are installed upstream and downstream of the junction MP where the refrigerant circuit C1 merges with the oil return path RP to monitor the temperature change before and after the junction. When the temperature after the junction is higher than the temperature before the junction, it can be determined that bypass refrigerant is present.
  • the flow rate adjustment mechanism 16 reduces the flow rate compared to when the temperature difference is smaller than the judgment threshold.
  • the control device 600 calculates the temperature difference from the output of the temperature sensors 17C and 17D and controls the flow rate adjustment mechanism 16 as described above.
  • FIG. 7 is a diagram showing the configuration of a refrigeration cycle apparatus of the fifth embodiment.
  • a refrigeration cycle apparatus 1004 shown in Fig. 7 includes an electronic expansion valve (Linear Expansion Valve: LEV) 16A as a flow rate control mechanism 16.
  • LEV Linear Expansion Valve
  • the configuration of the other parts of the refrigeration cycle apparatus 1004 is similar to that of the refrigeration cycle apparatus 1001 in Fig. 1, and description thereof will not be repeated.
  • control device 600 can increase or decrease the flow rate of the fluid (refrigerant and refrigeration oil) passing through the oil return path RP based on the output of the refrigerant detection device 17.
  • the refrigerant detection device 17 can use any of the configurations shown in the third and fourth embodiments.
  • the control device 600 can control the flow rate using any of the controls shown in the first and second embodiments.
  • FIG. 8 is a diagram showing the configuration of a refrigeration cycle apparatus of the sixth embodiment.
  • a flow rate adjustment mechanism 16 includes a solenoid valve 16B and a capillary tube 16C arranged in series in an oil return path RP.
  • the configuration of the other parts of the refrigeration cycle apparatus 1005 is similar to that of the refrigeration cycle apparatus 1001 in Fig. 1, and description thereof will not be repeated.
  • a capillary tube 16C and a solenoid valve 16B are installed in the oil return path RP, and the solenoid valve 16B is controlled to open when the flow rate is increased and closed when the flow rate is decreased. This allows the control device 600 to adjust the flow rates of the refrigerant and refrigeration oil passing through the oil return path RP.
  • the refrigerant detection device 17 can use any of the configurations shown in the third and fourth embodiments.
  • the control device 600 can control the flow rate using any of the controls shown in the first and second embodiments.
  • the oil return route RP carries high-temperature refrigeration oil and refrigerant discharged from the compressor 10, so the LEV must have high heat resistance.
  • an LEV placed in the oil return route RP as used in FIG. 7 may be a special specification and an expensive component.
  • the capillary tube and solenoid valve have a simple structure and high heat resistance, so that general components can be used in the oil return route, making it possible to construct a flow rate adjustment mechanism at low cost.
  • Embodiment 7 a third specific example of the flow rate adjustment mechanism described in the first embodiment will be described.
  • Fig. 9 is a diagram showing the configuration of a refrigeration cycle device of the seventh embodiment.
  • an oil return path RP branches into a flow path RP1 and a flow path RP2 at a branch point BP1 and then merges at a merging point MP1.
  • the flow rate adjustment mechanism 16 includes an electromagnetic valve 16B and a capillary tube 16C arranged in series in the flow path RP1, and a capillary tube 16D arranged in the flow path RP2.
  • the refrigerant detection device 17 can use any of the configurations shown in the third and fourth embodiments.
  • the control device 600 can control the flow rate using any of the controls shown in the first and second embodiments.
  • the oil return path RP is branched into RP1 and RP2 in parallel, with capillary tubes 16C and 16D installed in each, and a solenoid valve 16B installed in one of the paths, RP1.
  • the control device 600 can adjust the flow rate by opening solenoid valve 16B when increasing the flow rate and closing solenoid valve 16B when decreasing the flow rate.
  • the present disclosure relates to a refrigeration cycle device.
  • the refrigeration cycle device shown in Figs. 1 to 9 includes a compressor 10, an oil separator 11, a heat exchanger 13, an expansion valve 14, and a heat exchanger 15.
  • the compressor 10, the oil separator 11, the heat exchanger 13, the expansion valve 14, and the heat exchanger 15 form a refrigerant circuit C1 in which a refrigerant circulates.
  • the refrigeration cycle device further includes an oil return path RP that returns refrigeration oil from the oil separator 11 to the suction section of the compressor 10, a flow rate adjustment mechanism 16 disposed in the oil return path RP, and a refrigerant detection device 17 that detects the refrigerant flowing in the oil return path RP.
  • the flow rate adjustment mechanism 16 controls the flow rate of the fluid passing through the oil return path RP according to the output of the refrigerant detection device 17.
  • the refrigeration cycle device further includes a control device 600 that controls the compressor 10 and the flow rate adjustment mechanism 16.
  • the control device 600 is configured to execute a first control (S15) that keeps the flow rate of the flow rate adjustment mechanism 16 fixed while the compressor 10 is operating, and a second control (S12 to S14) that controls the flow rate of the flow rate adjustment mechanism 16 in response to the output of the refrigerant detection device 17 while the compressor 10 is operating.
  • control device 600 is configured to execute the first control when the operating frequency of the compressor 10 is higher than a threshold value, and to execute the second control when the operating frequency is lower than the threshold value.
  • control device 600 is configured to execute the first control when the pressure difference between the suction section and the discharge section of the compressor 10 is smaller than a threshold value, and to execute the second control when the pressure difference is larger than the threshold value.
  • the refrigerant detection device 17 includes a temperature sensor 17A arranged upstream of the flow rate adjustment mechanism 16 in the oil return path RP, and a temperature sensor 17B arranged downstream of the flow rate adjustment mechanism 16 in the oil return path RP.
  • the flow rate adjustment mechanism 16 reduces the flow rate compared to when the temperature difference is smaller than the judgment threshold.
  • the oil return path RP merges with the refrigerant circuit C1 at a junction MP between the heat exchanger 15 in the refrigerant circuit C1 and the suction port of the compressor 10.
  • the refrigerant detection device 17 includes a temperature sensor 17C arranged upstream of the junction MP in the refrigerant circuit C1, and a temperature sensor 17D arranged downstream of the junction MP in the oil return path RP.
  • the flow rate adjustment mechanism 16 reduces the flow rate compared to when the temperature difference is smaller than the determination threshold.
  • the flow rate adjustment mechanism 16 includes an electronic expansion valve 16A.
  • the flow rate adjustment mechanism 16 includes a solenoid valve 16B and a capillary tube 16C arranged in series in the oil return path RP.

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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

Un dispositif à cycle frigorifique (1001) est équipé d'un compresseur (10), d'un séparateur d'huile (11), d'un premier échangeur de chaleur (13), d'un détendeur (14) et d'un second échangeur de chaleur (15). Le compresseur (10), le séparateur d'huile (11), le premier échangeur de chaleur (13), le détendeur (14) et le second échangeur de chaleur (15) constituent un circuit de fluide frigorifique (C1) dans lequel circule un fluide frigorifique. Ce dispositif à cycle frigorifique (1001) est en outre équipé d'un passage d'huile de retour (RP) par lequel est renvoyée une huile de réfrigérateur du séparateur d'huile (11) à un orifice d'admission du compresseur (10), d'un mécanisme de régulation d'écoulement (16) positionné dans le passage d'huile de retour (RP), et d'un dispositif de détection de fluide frigorifique (17) qui détecte le fluide frigorifique traversant le passage d'huile de retour (RP). Le mécanisme de régulation d'écoulement (16) régule l'écoulement d'un fluide qui traverse le passage d'huile de retour (RP) en fonction de la sortie du dispositif de détection de fluide frigorifique (17).
PCT/JP2022/043416 2022-11-24 2022-11-24 Dispositif à cycle frigorifique WO2024111097A1 (fr)

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PCT/JP2022/043416 WO2024111097A1 (fr) 2022-11-24 2022-11-24 Dispositif à cycle frigorifique

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11107966A (ja) * 1997-10-06 1999-04-20 Mitsubishi Electric Corp 空気調和装置
JP2002257427A (ja) * 2001-02-28 2002-09-11 Mitsubishi Electric Corp 冷凍空調装置、及びその運転方法
JP2011127777A (ja) * 2009-12-15 2011-06-30 Mitsubishi Electric Corp ヒートポンプ装置及びヒートポンプ装置の運転方法
WO2018207274A1 (fr) * 2017-05-10 2018-11-15 三菱電機株式会社 Dispositif de séparation d'huile et dispositif à cycle de réfrigération
WO2022085112A1 (fr) * 2020-10-21 2022-04-28 三菱電機株式会社 Unité de source de froid et dispositif à cycle de réfrigération
WO2022130637A1 (fr) * 2020-12-18 2022-06-23 三菱電機株式会社 Ensemble source de chaleur froide et dispositif à cycle frigorifique

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11107966A (ja) * 1997-10-06 1999-04-20 Mitsubishi Electric Corp 空気調和装置
JP2002257427A (ja) * 2001-02-28 2002-09-11 Mitsubishi Electric Corp 冷凍空調装置、及びその運転方法
JP2011127777A (ja) * 2009-12-15 2011-06-30 Mitsubishi Electric Corp ヒートポンプ装置及びヒートポンプ装置の運転方法
WO2018207274A1 (fr) * 2017-05-10 2018-11-15 三菱電機株式会社 Dispositif de séparation d'huile et dispositif à cycle de réfrigération
WO2022085112A1 (fr) * 2020-10-21 2022-04-28 三菱電機株式会社 Unité de source de froid et dispositif à cycle de réfrigération
WO2022130637A1 (fr) * 2020-12-18 2022-06-23 三菱電機株式会社 Ensemble source de chaleur froide et dispositif à cycle frigorifique

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