US20240255200A1 - Accumulator and refrigeration cycle apparatus - Google Patents

Accumulator and refrigeration cycle apparatus Download PDF

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Publication number
US20240255200A1
US20240255200A1 US18/561,074 US202118561074A US2024255200A1 US 20240255200 A1 US20240255200 A1 US 20240255200A1 US 202118561074 A US202118561074 A US 202118561074A US 2024255200 A1 US2024255200 A1 US 2024255200A1
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Prior art keywords
expansion valve
refrigerant
accumulator
compressor
heat exchanger
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US18/561,074
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English (en)
Inventor
Hiroki Ishiyama
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Mitsubishi Electric Corp
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Mitsubishi Electric Corp
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Publication of US20240255200A1 publication Critical patent/US20240255200A1/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat
    • F25B43/006—Accumulators
    • 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
    • F25B40/00—Subcoolers, desuperheaters or superheaters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
    • F25B41/22—Disposition of valves, e.g. of on-off valves or flow control valves between evaporator and compressor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/30—Expansion means; Dispositions thereof
    • F25B41/31—Expansion valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat
    • F25B43/02—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat for separating lubricants from the refrigerant
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B13/00—Compression machines, plants or systems, with reversible cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2500/00—Problems to be solved
    • F25B2500/16—Lubrication
    • 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
    • F25B2500/00—Problems to be solved
    • F25B2500/18—Optimization, e.g. high integration of refrigeration components
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/25—Control of valves
    • F25B2600/2513—Expansion valves

Definitions

  • the present disclosure relates to an accumulator and a refrigeration cycle apparatus.
  • a refrigeration cycle apparatus including an accumulator has conventionally been known.
  • the accumulator is provided between an evaporator and a compressor. Refrigerant that flows out of the evaporator flows into the accumulator. Refrigerant that flows into the accumulator is composed of gas refrigerant and a liquid mixture. The liquid mixture contains liquid refrigerant and oil for lubrication of the compressor.
  • the accumulator prevents such liquid carry-over as flow of liquid refrigerant into the compressor due to accumulation of excessive liquid refrigerant.
  • the accumulator prevents oil exhaustion due to increase in amount of discharge of oil from the compressor, by return of oil from an oil return portion.
  • Too large a diameter of a hole in the oil return portion may lead to increase in inflow flow rate and cause liquid carry-over.
  • the diameter of the hole is simply made smaller, the inflow flow rate may become too low and return of oil may be insufficient.
  • a length of an outflow pipe may be increased or a straw tube for return of oil may separately be provided in order to increase an amount of return of oil, the apparatus increases in size.
  • the refrigeration cycle apparatus in PTL 1 activates a hole opening adjustment valve provided in the mixing ratio adjustment apparatus by driving an electric motor for suppression of a superheated state of refrigerant.
  • Such a refrigeration cycle apparatus in PTL 1 is able to regulate a flow rate of the liquid mixture that flows from the accumulator into a compressor, whereas it is unable to return a proper amount of oil because an amount of oil with respect to the liquid mixture is not taken into consideration.
  • the mixing ratio adjustment apparatus has been a large apparatus including an electric motor.
  • An object of the present disclosure is to provide an accumulator small in size and a refrigeration cycle apparatus that allow an appropriate amount of oil to flow into a compressor.
  • the present disclosure relates to an accumulator provided between an evaporator of a refrigeration cycle apparatus and a refrigerant suction side of a compressor of the refrigeration cycle apparatus.
  • the accumulator includes a container where refrigerant is accumulated, an inflow pipe for flow of refrigerant into the container, an outflow pipe for flow of refrigerant out of the container, an oil return portion provided with an opening for suction of oil, and a decompressing apparatus to decompress refrigerant.
  • the decompressing apparatus and the oil return portion are arranged on the outflow pipe.
  • an appropriate amount of oil can flow into the compressor.
  • FIG. 1 is a diagram showing a circuit configuration of a refrigeration cycle apparatus in a first embodiment.
  • FIG. 2 is a diagram for illustrating an accumulator in the first embodiment.
  • FIG. 3 is a diagram showing a cross-section along III-III in FIG. 2 .
  • FIG. 4 is a diagram for illustrating an accumulator in a second embodiment.
  • FIG. 5 is a diagram showing a cross-section along V-V in FIG. 4 .
  • FIG. 6 is a diagram showing a circuit configuration of a refrigeration cycle apparatus in a third embodiment.
  • FIG. 7 is a diagram for illustrating an accumulator in the third embodiment.
  • FIG. 8 is a flowchart showing control of a second expansion valve in the third embodiment.
  • FIG. 9 is a diagram showing a circuit configuration of a refrigeration cycle apparatus in a fourth embodiment.
  • FIG. 10 is a flowchart showing control of the second expansion valve in the fourth embodiment.
  • FIG. 11 is a diagram showing a circuit configuration of a refrigeration cycle apparatus in a fifth embodiment.
  • FIG. 12 is a flowchart showing control of a first expansion valve and the second expansion valve in the fifth embodiment.
  • FIG. 13 is a diagram showing a circuit configuration of a refrigeration cycle apparatus in a sixth embodiment.
  • FIG. 1 is a diagram showing a circuit configuration of a refrigeration cycle apparatus 100 in a first embodiment.
  • Refrigeration cycle apparatus 100 includes a compressor 1 , a first heat exchanger 2 , a second heat exchanger 4 , a first expansion valve 3 , an accumulator 5 , and a control device 10 .
  • Refrigeration cycle apparatus 100 has refrigerant circulate sequentially through compressor 1 , first heat exchanger 2 , first expansion valve 3 , second heat exchanger 4 , and accumulator 5 during a heating operation.
  • Compressor 1 suctions, compresses, and discharges refrigerant.
  • First heat exchanger 2 functions as a condenser. First heat exchanger 2 exchanges heat between air and refrigerant with the use of a not-shown fan to condense refrigerant.
  • First expansion valve 3 is arranged between first heat exchanger 2 and second heat exchanger 4 and expands or decompresses refrigerant. First expansion valve 3 is, for example, an apparatus capable of freely controlling an opening of an electronic expansion valve or the like. Control device 10 controls the opening of first expansion valve 3 .
  • Second heat exchanger 4 functions as an evaporator. Second heat exchanger 4 evaporates low-pressure liquid refrigerant decompressed by first expansion valve 3 . Gas-liquid two-phase refrigerant evaporated by second heat exchanger 4 flows into accumulator 5 . Refrigerating machine oil (which is also simply referred to as oil below) is enclosed in a refrigerant circuit of refrigeration cycle apparatus 100 . Accumulator 5 provided between compressor 1 and second heat exchanger 4 separates into gas and liquid, gas-liquid two-phase refrigerant composed of gas refrigerant and a liquid mixture of oil and liquid refrigerant. Gas refrigerant and the liquid mixture adjusted in amount of oil that have passed through accumulator 5 return to compressor 1 .
  • Control device 10 includes a central processing unit (CPU) 11 , a memory 12 (a read only memory (ROM) and a random access memory (RAM)), and a not-shown input and output apparatus for input of various signals.
  • CPU 11 develops on the RAM or the like, programs stored in the ROM and executes the programs.
  • the programs stored in the ROM are programs in which a procedure of processing in control device 10 is written.
  • Control device 10 controls each device in refrigeration cycle apparatus 100 in accordance with these programs. In this control, processing by dedicated hardware (electronic circuitry) can also be performed, without being limited to processing by software.
  • FIG. 2 is a diagram for illustrating accumulator 5 in the first embodiment.
  • Accumulator 5 includes a container 51 , an inflow pipe 52 , an outflow pipe 53 , an oil return portion 54 , and a decompressing pipe 56 as a decompressing apparatus.
  • a liquid mixture of liquid refrigerant and oil is accumulated in container 51 .
  • Inflow pipe 52 is used for flow of gas refrigerant and the liquid mixture into container 51 .
  • Inflow pipe 52 extends toward a wall surface in container 51 and has a bent tip end.
  • Outflow pipe 53 is bent in a U shape, and of gas refrigerant and the liquid mixture, gas refrigerant flows in through an inlet of outflow pipe 53 . Gas refrigerant and the liquid mixture adjusted in amount of oil flow out of an outlet of outflow pipe 53 .
  • Outflow pipe 53 is in such a shape that a gas refrigerant inflow end is located at a position higher than oil return portion 54 and decompressing pipe 56 in container 51 and a gas refrigerant outflow end is located at a position protruding out of container 51 .
  • Oil return portion 54 is an opening for suction of oil, the opening being provided in an arc portion of outflow pipe 53 .
  • Accumulator 5 prevents liquid carry-over which causes lowering in capability or reliability of compressor 1 , by returning oil (refrigerating machine oil) as the liquid mixture, together with a small amount of liquid refrigerant, from oil return portion 54 to compressor 1 .
  • Gas refrigerant and oil flow out of the outlet of outflow pipe 53 .
  • a meshed cover for removal of dirt is provided at the opening of oil return portion 54 , it is not shown for the sake of convenience of description.
  • Decompressing pipe 56 is provided between the inlet of outflow pipe 53 and oil return portion 54 and it is smaller in diameter than outflow pipe 53 . Decompressing pipe 56 decompresses gas refrigerant. When decompressing pipe 56 is provided at a tip end of outflow pipe 53 , a flow velocity at the tip end increases and efficiency in gas-liquid separation becomes poor. When the decompressing pipe is provided in the middle of outflow pipe 53 , however, efficiency of gas-liquid separation can be prevented from lowering.
  • FIG. 3 is a diagram showing a cross-section along III-III in FIG. 2 .
  • oil return portion 54 provided with a hole smaller in diameter than outflow pipe 53 is arranged in outflow pipe 53 .
  • Relation of P2>P1 is satisfied where P1 represents a pressure in outflow pipe 53 , P2 represents a pressure outside outflow pipe 53 , and ⁇ P represents a pressure in oil return portion 54 .
  • a flow of refrigerant in the first embodiment will be described.
  • Gas refrigerant and the liquid mixture of liquid refrigerant and oil that have flowed out of second heat exchanger 4 flow into accumulator 5 .
  • Gas refrigerant and the liquid mixture pass through inflow pipe 52 in accumulator 5 and flow into container 51 .
  • Gas refrigerant and the liquid mixture are separated into gas and liquid; gas refrigerant flows into outflow pipe 53 and the liquid mixture is accumulated in container 51 .
  • Gas refrigerant that has flowed into outflow pipe 53 flows through decompressing pipe 56 while the pressure thereof is lowered. Lowering of the pressure can also be expressed as pressure loss.
  • the liquid mixture accumulated in container 51 flows from oil return portion 54 into outflow pipe 53 .
  • accumulator 5 in accordance with a pressure difference ⁇ P between P2 which is the pressure at the inlet of oil return portion 54 in container 51 and pressure P1 in the inside of outflow pipe 53 , oil in a lower portion of the liquid mixture flows in from oil return portion 54 and merges with gas refrigerant. Merged gas refrigerant and oil pass through outflow pipe 53 and flow out of accumulator 5 into compressor 1 .
  • decompressing pipe 56 and oil return portion 54 are sequentially arranged in the middle of outflow pipe 53 in a direction of flow of refrigerant. Therefore, a differential pressure can be increased without increase in size of accumulator 5 , and an appropriate amount of oil can flow into compressor 1 .
  • FIG. 4 is a diagram for illustrating an accumulator 5 A in a second embodiment.
  • Accumulator 5 A in the second embodiment is different from accumulator 5 in the first embodiment in that a first oil return portion 54 A and a second return portion 54 B are provided as two oil return portions and decompressing pipe 56 is arranged between the two oil return portions.
  • the accumulator is otherwise similar in construction to accumulator 5 in the first embodiment. Differences from the first embodiment will mainly be described in the description below.
  • First oil return portion 54 A and second oil return portion 54 B are openings for suction of oil provided in the arc portion of outflow pipe 53 .
  • Accumulator 5 A prevents liquid carry-over which causes lowering in capability or reliability of compressor 1 , by returning oil from first oil return portion 54 A and second oil return portion 54 B to compressor 1 .
  • Gas refrigerant and oil flow out of the outlet of outflow pipe 53 .
  • Decompressing pipe 56 is provided between first oil return portion 54 A and second oil return portion 54 B and it is smaller in diameter than outflow pipe 53 . Decompressing pipe 56 decompresses gas refrigerant and the liquid mixture.
  • FIG. 5 is a diagram showing a cross-section along V-V in FIG. 4 .
  • second oil return portion 54 B smaller in diameter than outflow pipe 53 is provided in outflow pipe 53 .
  • Relation of P2′>P1′ is satisfied where P1′ represents a pressure in outflow pipe 53 , P2′ represents a pressure outside outflow pipe 53 , and ⁇ P′ represents a pressure in second oil return portion 54 B.
  • First oil return portion 54 A in the cross-section along III-III in FIG. 4 is the same as oil return portion 54 in FIG. 3 .
  • Relation of P2>P1 is satisfied where P1 represents a pressure in outflow pipe 53 , P2 represents a pressure outside the outflow pipe, and ⁇ P represents a pressure in first oil return portion 54 A.
  • Accumulator 5 A satisfies relation of P2 ⁇ P2′ and satisfies relation of P1>P1′ attributed to decompressing pipe 56 . Therefore, the flow rate in second oil return portion 54 B is higher than the flow rate in first oil return portion 54 A.
  • a flow of refrigerant in the second embodiment will be described.
  • Gas refrigerant and the liquid mixture of liquid refrigerant and oil that have flowed out of second heat exchanger 4 flow into accumulator 5 A.
  • Gas refrigerant and the liquid mixture pass through inflow pipe 52 of accumulator 5 A and flow into container 51 .
  • Gas refrigerant and the liquid mixture are separated into gas and liquid; gas refrigerant flows into outflow pipe 53 and the liquid mixture is accumulated in container 51 .
  • Gas refrigerant that has flowed into outflow pipe 53 flows through decompressing pipe 56 while the pressure thereof is lowered.
  • the liquid mixture accumulated in container 51 flows from first oil return portion 54 A into outflow pipe 53 .
  • accumulator 5 A in accordance with pressure difference ⁇ P between P2 which is the pressure at the inlet of first oil return portion 54 A in container 51 and pressure P1 in the inside of outflow pipe 53 , oil in the lower portion of the liquid mixture flows in from first oil return portion 54 A and merges with gas refrigerant. Merged gas refrigerant and oil flow through decompressing pipe 56 while the pressure thereof is lowered.
  • first oil return portion 54 A, decompressing pipe 56 , and second oil return portion 54 B are sequentially arranged in the middle of outflow pipe 53 in the direction of flow of refrigerant. Therefore, when the flow rate of refrigerant in the refrigerant circuit is low, the flow rate of inflow into first oil return portion 54 A can be lowered to suppress liquid carry-over and to improve performance. When the flow rate of refrigerant in the refrigerant circuit is high, oil can return through first oil return portion 54 A and second return portion 54 B and reliability can be improved. An appropriate amount of oil can thus flow into compressor 1 without increase in size of accumulator 5 A.
  • FIG. 6 is a diagram showing a circuit configuration of a refrigeration cycle apparatus 100 A in a third embodiment.
  • Refrigeration cycle apparatus 100 A in the third embodiment is different from refrigeration cycle apparatus 100 in the first embodiment in that accumulator 5 is changed to an accumulator 5 B and a discharge superheat sensor 61 is provided as a sensor between compressor 1 and first heat exchanger 2 .
  • the refrigeration cycle apparatus is otherwise similar in configuration to refrigeration cycle apparatus 100 in the first embodiment. Differences from the first embodiment will mainly be described in the description below.
  • Discharge superheat sensor 61 is a sensor to detect a superheat of refrigerant discharged from compressor 1 .
  • the discharge superheat refers to a superheat of refrigerant gas expressed by a difference between a temperature of refrigerant discharged from compressor 1 (which is also referred to as a discharge temperature below) and a saturation gas temperature corresponding to a pressure of refrigerant discharged from the compressor (which is also referred to as a discharge pressure below).
  • Discharge superheat sensor 61 measures the discharge temperature and the discharge pressure.
  • a signal resulting from measurement is transmitted to control device 10 .
  • Control device 10 calculates as a sensing value, the discharge superheat based on a detected signal value.
  • a differential pressure gauge may be employed as discharge superheat sensor 61 .
  • FIG. 7 is a diagram for illustrating an accumulator 5 B in the third embodiment.
  • Accumulator 5 B in the third embodiment is different from accumulator 5 in the first embodiment in position of oil return portion 54 and in arrangement of a second expansion valve 57 instead of decompressing pipe 56 as the decompressing apparatus.
  • the accumulator is otherwise similar in construction to accumulator 5 in the first embodiment. Differences from the first embodiment will mainly be described in the description below.
  • Oil return portion 54 is an opening for suction of oil, the opening being provided around the center in the arc portion of outflow pipe 53 .
  • Second expansion valve 57 is provided between the inlet of outflow pipe 53 and oil return portion 54 and decompresses gas refrigerant that flows in from outflow pipe 53 .
  • An opening of second expansion valve 57 is adjustable in accordance with the flow rate in the refrigerant circuit. As shown in FIG. 6 , control device 10 controls the opening of second expansion valve 57 based on the sensing value of the discharge superheat.
  • FIG. 8 is a flowchart showing control of second expansion valve 57 in the third embodiment.
  • control device 10 determines in step S 1 whether or not compressor 1 is operating. When control device 10 determines that compressor 1 is not operating (NO in step S 1 ), the process ends. When control device 10 determines that compressor 1 is operating (YES in step S 1 ), transition to processing in step S 2 is made.
  • control device 10 obtains the sensing value of the discharge superheat based on the value obtained by discharge superheat sensor 61 .
  • Control device 10 compares a predetermined reference value and the sensing value with each other (step S 3 ).
  • control device 10 determines that the sensing value is smaller than the reference value (YES in step S 3 )
  • it decreases the opening of second expansion valve 57 from the current opening (step S 4 ) and transition to processing in step S 1 is made.
  • control device 10 determines that the sensing value is equal to or larger than the reference value (NO in step S 3 )
  • it increases the opening of second expansion valve 57 from the current opening (step S 5 ) and transition to processing in step S 1 is made.
  • Control device 10 may increase or decrease the opening of second expansion valve 57 in predetermined steps. Control device 10 may quit processing for adjusting the opening when the opening of second expansion valve 57 is set to a predetermined smallest or largest opening.
  • a flow of refrigerant in the third embodiment will be described.
  • Gas refrigerant and the liquid mixture of liquid refrigerant and oil that have flowed out of second heat exchanger 4 flow into accumulator 5 B.
  • Gas refrigerant and the liquid mixture pass through inflow pipe 52 of accumulator 5 B and flow into container 51 .
  • Gas refrigerant and the liquid mixture are separated into gas and liquid; gas refrigerant flows into outflow pipe 53 and the liquid mixture is accumulated in container 51 .
  • Gas refrigerant that has flowed into outflow pipe 53 flows through second expansion valve 57 while the pressure thereof is lowered.
  • the liquid mixture accumulated in container 51 flows from oil return portion 54 into outflow pipe 53 .
  • accumulator 5 B in accordance with pressure difference ⁇ P between P2 which is the pressure at the inlet of oil return portion 54 in container 51 and pressure P1 in the inside of outflow pipe 53 , oil in the lower portion of the liquid mixture flows in from oil return portion 54 and merges with gas refrigerant. Merged gas refrigerant and oil pass through outflow pipe 53 and flow out of accumulator 5 B into compressor 1 .
  • the sensing value is smaller than the reference value.
  • the opening of second expansion valve 57 decreases from the current opening.
  • decrease in opening of second expansion valve 57 leads to increase in lowering of the pressure in second expansion valve 57 .
  • Refrigeration cycle apparatus 100 A the pressure difference between the inlet and the outlet of outflow pipe 53 can be increased without increase in size of accumulator 5 B, and the inflow flow rate of oil into oil return portion 54 increases.
  • Refrigeration cycle apparatus 100 A can suppress oil exhaustion and improve reliability by increasing the amount of return of oil to compressor 1 when return of oil is necessary during the unstable operation at the time of start-up or the like.
  • the sensing value is equal to or larger than the reference value.
  • the opening of second expansion valve 57 increases from the current opening.
  • increase in opening of second expansion valve 57 leads to decrease in lowering of the pressure in second expansion valve 57 .
  • Refrigeration cycle apparatus 100 A the pressure difference between the inlet and the outlet of outflow pipe 53 can be decreased without increase in size of accumulator 5 B, and the inflow flow rate of oil into oil return portion 54 lowers.
  • Refrigeration cycle apparatus 100 A can prevent liquid carry-over by decreasing the amount of return of oil to compressor 1 when return of oil is not necessary during the stable operation, and can obtain improvement in reliability and performance. Since pressure loss in outflow pipe 53 is reduced during the stable operation in refrigeration cycle apparatus 100 A, performance of a circuit apparatus as a whole can be improved.
  • FIG. 9 is a diagram showing a circuit configuration of a refrigeration cycle apparatus 100 B in a fourth embodiment.
  • Refrigeration cycle apparatus 100 B in the fourth embodiment is different from refrigeration cycle apparatus 100 A in the third embodiment in that an oil concentration sensor 62 instead of discharge superheat sensor 61 is provided as the sensor in compressor 1 .
  • the refrigeration cycle apparatus is otherwise similar in configuration to refrigeration cycle apparatus 100 A in the third embodiment. Differences from the third embodiment will mainly be described in the description below.
  • Oil concentration sensor 62 is a sensor to detect a concentration of oil in compressor 1 .
  • a signal relating to the concentration of oil measured by the oil concentration sensor is transmitted to control device 10 .
  • Control device 10 calculates as the sensing value, the concentration of oil based on a detected signal value.
  • Control device 10 controls second expansion valve 57 based on the sensing value of the concentration of oil.
  • a sensor to detect a state of liquid such as a sensor to sense a concentration of liquid based on a capacitance, a sensor to sense ultrasound, a sensor to sense an index of refraction, or the like may be employed as oil concentration sensor 62 .
  • FIG. 10 is a flowchart showing control of second expansion valve 57 in the fourth embodiment.
  • control device 10 determines in step S 11 whether or not compressor 1 is operating. When control device 10 determines that compressor 1 is not operating (NO in step S 11 ), the process ends. When control device 10 determines that compressor 1 is operating (YES in step S 11 ), transition to processing in step S 12 is made.
  • control device 10 obtains the sensing value from oil concentration sensor 62 .
  • Control device 10 compares a predetermined reference value and the sensing value with each other (step S 13 ). When control device 10 determines that the sensing value is smaller than the reference value (YES in step S 13 ), it decreases the opening of second expansion valve 57 from the current opening (step S 14 ) and transition to processing in step S 11 is made. When control device 10 determines that the sensing value is equal to or larger than the reference value (NO in step S 13 ), it increases the opening of second expansion valve 57 from the current opening (step S 15 ) and transition to processing in step S 11 is made.
  • Control device 10 may increase or decrease the opening of second expansion valve 57 in predetermined steps. Control device 10 may quit processing for adjusting the opening when the opening of second expansion valve 57 is set to a predetermined smallest or largest opening.
  • the sensing value is smaller than the reference value.
  • the opening of second expansion valve 57 decreases from the current opening.
  • decrease in opening of second expansion valve 57 leads to increase in lowering of the pressure in second expansion valve 57 .
  • Refrigeration cycle apparatus 100 B the pressure difference between the inlet and the outlet of outflow pipe 53 can be increased without increase in size of accumulator 5 B, and the inflow flow rate of oil into oil return portion 54 increases.
  • Refrigeration cycle apparatus 100 B can suppress oil exhaustion and improve reliability by increasing the amount of return of oil to compressor 1 when return of oil is necessary during the unstable operation at the time of start-up or the like.
  • the sensing value is equal to or larger than the reference value.
  • the opening of second expansion valve 57 increases from the current opening.
  • increase in opening of second expansion valve 57 leads to decrease in lowering of the pressure in second expansion valve 57 .
  • Refrigeration cycle apparatus 100 B the pressure difference between the inlet and the outlet of outflow pipe 53 can be decreased without increase in size of accumulator 5 B, and the inflow flow rate of oil into oil return portion 54 lowers.
  • Refrigeration cycle apparatus 100 B can prevent liquid carry-over by decreasing the amount of return of oil to compressor 1 when return of oil is not necessary during the stable operation and can obtain improvement in reliability and performance. Since pressure loss in outflow pipe 53 is reduced during the stable operation in refrigeration cycle apparatus 100 B, performance of the circuit apparatus as a whole can be improved.
  • FIG. 11 is a diagram showing a circuit configuration of a refrigeration cycle apparatus 100 C in a fifth embodiment.
  • Refrigeration cycle apparatus 100 C in the fifth embodiment is different from refrigeration cycle apparatus 100 A in the third embodiment in that a suction superheat sensor 63 instead of discharge superheat sensor 61 is provided as a sensor between second heat exchanger 4 and accumulator 5 B.
  • the refrigeration cycle apparatus is otherwise similar in configuration to refrigeration cycle apparatus 100 A in the third embodiment. Differences from the third embodiment will mainly be described in the description below.
  • Suction superheat sensor 63 is a sensor to detect a superheat of refrigerant to be suctioned into compressor 1 .
  • the suction superheat refers to the superheat of refrigerant gas expressed by a difference between a temperature of refrigerant to be suctioned by compressor 1 (which is also referred to as a suction temperature below) and a saturation gas temperature corresponding to a pressure of refrigerant to be suctioned by the compressor (which is also referred to as a suction pressure below).
  • Suction superheat sensor 63 measures the suction temperature and the suction pressure. A signal resulting from measurement is transmitted to control device 10 .
  • Control device 10 calculates as a sensing value, the suction superheat based on a detected signal value. Control device 10 controls second expansion valve 57 based on the sensing value of the suction superheat.
  • a differential pressure gauge may be employed as suction superheat sensor 63 .
  • FIG. 12 is a flowchart showing control of first expansion valve 3 and second expansion valve 57 in the fifth embodiment.
  • control device 10 determines whether or not it has received a signal to stop operation of compressor 1 , the signal being transmitted to control device 10 in response to an operation by a user.
  • control device 10 determines that it has not received the signal to stop operation of compressor 1 (NO in step S 21 )
  • the process ends.
  • control device 10 determines that it has received the signal to stop operation of compressor 1 (YES in step S 21 )
  • transition to processing in step S 22 is made.
  • step S 22 control device 10 determines whether or not compressor 1 is operating. When control device 10 determines that compressor 1 is not operating (NO in step S 22 ), the process ends. When control device 10 determines that compressor 1 is operating (YES in step S 22 ), transition to processing in step S 23 is made.
  • control device 10 obtains a sensing value of the suction superheat from a value obtained by suction superheat sensor 63 .
  • the control device then increases the opening of second expansion valve 57 from the current opening.
  • Control device 10 compares a predetermined reference value and the sensing value with each other (step S 25 ). When control device 10 determines that the sensing value is smaller than the reference value (YES in step S 25 ), it decreases the opening of first expansion valve 3 from the current opening (step S 26 ) and transition to processing in step S 21 is made. When control device 10 determines that the sensing value is equal to or larger than the reference value (NO in step S 25 ), it increases the opening of first expansion valve 3 from the current opening (step S 27 ) and transition to processing in step S 21 is made.
  • step S 21 control device 10 starts counting from a time point of reception of the signal to stop operation of compressor 1 .
  • the control device may increase a count value, and when transition to processing in step S 27 is made, the control device may reset the count value and set a stop flag.
  • Control device 10 may determine that the operation of compressor 1 has been stopped when the stop flag is set.
  • control device 10 adjusts the opening of first expansion valve 3 and second expansion valve 57 in processing from reception of the signal to stop compressor 1 until compressor 1 completely stops. The suction superheat can thus sufficiently be improved during a period from reception of the signal to stop compressor 1 until complete stop of compressor 1 .
  • Control device 10 may increase or decrease the opening of first expansion valve 3 and second expansion valve 57 in predetermined steps. Control device 10 may quit processing for adjusting the opening when the opening of first expansion valve 3 and second expansion valve 57 is set to a predetermined smallest or largest opening.
  • a degree of dryness of refrigerant at the inlet of accumulator 5 B may have increased due to continued operation.
  • gas refrigerant and oil flow into accumulator 5 B.
  • Gas refrigerant and oil pass through inflow pipe 52 of accumulator 5 B and flow into container 51 .
  • Gas refrigerant and oil are separated into gas and liquid; gas refrigerant flows into outflow pipe 53 and oil is accumulated in container 51 .
  • control device 10 increases the opening of second expansion valve 57 from the current opening during a period from reception of the signal to stop compressor 1 until complete stop of compressor 1 .
  • the opening of second expansion valve 57 increases so that lowering of the pressure in second expansion valve 57 decreases.
  • Refrigeration cycle apparatus 100 C can achieve improvement in reliability by accumulation of oil necessary for start-up in container 51 of accumulator 5 B at the time of stop of the operation.
  • control device 10 decreases the opening of first expansion valve 3 from the current opening as shown in step S 26 to increase lowering of the pressure in first expansion valve 3 .
  • Increase in degree of dryness of refrigerant thus increases the suction superheat.
  • an amount of oil that flows into accumulator 5 B can be increased.
  • control device 10 increases the opening of first expansion valve 3 from the current opening as shown in step S 27 to decrease lowering of the pressure in first expansion valve 3 .
  • Lowering in degree of dryness of refrigerant thus lowers the suction superheat.
  • an amount of oil that flows into accumulator 5 B can be decreased.
  • first expansion valve 3 and second expansion valve 57 are controlled at the time of reception of the stop signal to adjust the amount of oil that will flow into compressor 1 at the time of next start-up without increase in size of accumulator 5 B, and reliability of compressor 1 can be improved.
  • FIG. 13 is a diagram showing a circuit configuration of a refrigeration cycle apparatus 100 D in a sixth embodiment.
  • Refrigeration cycle apparatus 100 D in the sixth embodiment is different from refrigeration cycle apparatus 100 in the first embodiment in that a four-way valve 6 is provided on a refrigerant discharge side of compressor 1 .
  • the refrigeration cycle apparatus is otherwise similar in configuration to refrigeration cycle apparatus 100 in the first embodiment. Differences from the first embodiment will mainly be described in the description below.
  • Four-way valve 6 switches a direction of flow of refrigerant discharged from compressor 1 through a flow path by changing between a first state and a second state.
  • a solid line shown in four-way valve 6 is similar to the flow path in refrigeration cycle apparatus 100 in the first embodiment.
  • Control device 10 can control four-way valve 6 to switch the flow path shown with the solid line to a flow path shown with a dashed line.
  • refrigerant circulates sequentially through compressor 1 , second heat exchanger 4 , first expansion valve 3 , first heat exchanger 2 , and accumulator 5 .
  • Such a configuration including four-way valve 6 is applicable also to the second to fifth embodiments.
  • the present disclosure relates to accumulator 5 provided between second heat exchanger 4 which is an evaporator of refrigeration cycle apparatus 100 and a refrigerant suction side of compressor 1 .
  • Accumulator 5 includes container 51 where refrigerant is accumulated, inflow pipe 52 for flow of refrigerant into container 51 , outflow pipe 53 for flow of refrigerant out of container 51 , oil return portion 54 provided with an opening for suction of oil, and decompressing pipe 56 as a decompressing apparatus to decompress refrigerant.
  • decompressing pipe 56 and oil return portion 54 are arranged on outflow pipe 53 .
  • the decompressing apparatus is composed of decompressing pipe 56 smaller in diameter than the outflow pipe 53 .
  • decompressing pipe 56 and oil return portion 54 are arranged in this order on outflow pipe 53 in a direction of flow of refrigerant.
  • the oil return portion includes first oil return portion 54 A and second oil return portion 54 B.
  • the decompressing apparatus is composed of decompressing pipe 56 smaller in diameter than outflow pipe 53 .
  • first oil return portion 54 A, decompressing pipe 56 , and second oil return portion 54 B are arranged in this order on outflow pipe 53 in a direction of flow of refrigerant.
  • the decompressing apparatus is composed of second expansion valve 57 an opening of which is adjustable.
  • second expansion valve 57 and oil return portion 54 are arranged in this order on outflow pipe 53 in a direction of flow of refrigerant.
  • Refrigeration cycle apparatus 100 A includes compressor 1 , first heat exchanger 2 , second heat exchanger 4 , first expansion valve 3 , discharge superheat sensor 61 as the first sensor to measure a discharge superheat of refrigerant discharged from compressor 1 , and control device 10 to control an opening of second expansion valve 57 .
  • second heat exchanger 4 functions as the evaporator, refrigerant sequentially flows through compressor 1 , first heat exchanger 2 , first expansion valve 3 , second heat exchanger 4 , and accumulator 5 B.
  • Control device 10 controls an opening of second expansion valve 57 in accordance with the discharge superheat of refrigerant calculated from a value obtained by discharge superheat sensor 61 .
  • Refrigeration cycle apparatus 100 B includes compressor 1 , first heat exchanger 2 , second heat exchanger 4 , first expansion valve 3 , oil concentration sensor 62 as the second sensor to measure a state of oil in compressor 1 , and control device 10 to control an opening of second expansion valve 57 .
  • second heat exchanger 4 functions as the evaporator, refrigerant sequentially flows through compressor 1 , first heat exchanger 2 , first expansion valve 3 , second heat exchanger 4 , and accumulator 5 B.
  • Control device 10 controls an opening of second expansion valve 57 in accordance with the state of oil detected by oil concentration sensor 62 .
  • Refrigeration cycle apparatus 100 C includes compressor 1 , first heat exchanger 2 , second heat exchanger 4 , first expansion valve 3 , suction superheat sensor 63 as the third sensor to measure a suction superheat of refrigerant that flows into accumulator 5 B, and control device 10 to control an opening of first expansion valve 3 and second expansion valve 57 .
  • second heat exchanger 4 functions as the evaporator, refrigerant sequentially flows through compressor 1 , first heat exchanger 2 , first expansion valve 3 , second heat exchanger 4 , and accumulator 5 B.
  • control device 10 After control device 10 receives a signal to stop compressor 1 , control device 10 increases the opening of second expansion valve 57 as compared with the opening before compressor 1 is stopped, and controls the opening of first expansion valve 3 in accordance with the suction superheat of refrigerant calculated from a value obtained by suction superheat sensor 63 .
  • Refrigeration cycle apparatus 100 includes compressor 1 , first heat exchanger 2 , second heat exchanger 4 , and first expansion valve 3 .
  • second heat exchanger 4 functions as the evaporator, refrigerant sequentially flows through compressor 1 , first heat exchanger 2 , first expansion valve 3 , second heat exchanger 4 , and accumulator 5 .
  • Accumulator 5 , 5 A, or 5 B in the present embodiment is configured as above, so that an appropriate amount of oil can flow into compressor 1 owing to accumulator 5 small in size.
  • Refrigeration cycle apparatus 100 , 100 A, 100 B, or 100 C in the present embodiment is configured as above to implement a refrigerant circuit in which an appropriate amount of oil flows into compressor 1 owing to accumulator 5 small in size.
  • accumulator 5 may be varied in size of the opening of oil return portion 54 and in diameter of the decompressing pipe as appropriate, depending on the flow rate of refrigerant.
  • three or more openings as the oil return portions may be provided.
  • the number of oil return portions can thus be changed depending on the flow rate.
  • Accumulator 5 A may be different in size of the opening for each of a plurality of oil return portions.
  • Accumulator 5 A may be provided with decompressing pipe 56 in each interval between oil return portions, or the plurality of decompressing pipes 56 may be different from one another in diameter.
  • suction superheat sensor 63 is provided between second heat exchanger 4 and accumulator 5 B. Suction superheat sensor 63 may be provided between accumulator 5 B and compressor 1 .

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  • Engineering & Computer Science (AREA)
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  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Power Engineering (AREA)
  • Compression-Type Refrigeration Machines With Reversible Cycles (AREA)
US18/561,074 2021-07-07 2021-07-07 Accumulator and refrigeration cycle apparatus Abandoned US20240255200A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4733689A1 (en) * 2024-10-22 2026-04-29 Trane International Inc. System and method for lubricant quality control of an hvacr system

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3798921A (en) * 1973-03-26 1974-03-26 Gen Motors Corp Air conditioning system with freeze throttling valve
US20150128629A1 (en) * 2012-05-23 2015-05-14 Daikin Industries, Ltd. Refrigeration apparatus

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6051025B2 (ja) * 1977-09-07 1985-11-12 株式会社日立製作所 フロ−ト作動式膨脹装置を有するアキュムレ−タ
JPH0752051B2 (ja) * 1988-12-05 1995-06-05 三菱電機株式会社 アキュームレータ
JPH06249549A (ja) * 1992-03-27 1994-09-06 Mitsubishi Heavy Ind Ltd アキュムレータ
JP5974960B2 (ja) 2013-04-08 2016-08-23 株式会社デンソー 電池温度調整装置
EP3088819B1 (en) * 2015-01-23 2021-09-15 Mitsubishi Electric Corporation Air conditioning device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3798921A (en) * 1973-03-26 1974-03-26 Gen Motors Corp Air conditioning system with freeze throttling valve
US20150128629A1 (en) * 2012-05-23 2015-05-14 Daikin Industries, Ltd. Refrigeration apparatus

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4733689A1 (en) * 2024-10-22 2026-04-29 Trane International Inc. System and method for lubricant quality control of an hvacr system

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WO2023281653A1 (ja) 2023-01-12
CN117581070A (zh) 2024-02-20

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