WO2023139758A1 - 空気調和装置 - Google Patents

空気調和装置 Download PDF

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Publication number
WO2023139758A1
WO2023139758A1 PCT/JP2022/002222 JP2022002222W WO2023139758A1 WO 2023139758 A1 WO2023139758 A1 WO 2023139758A1 JP 2022002222 W JP2022002222 W JP 2022002222W WO 2023139758 A1 WO2023139758 A1 WO 2023139758A1
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WO
WIPO (PCT)
Prior art keywords
refrigerant
heat exchanger
evaporator
flow path
air conditioner
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PCT/JP2022/002222
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English (en)
French (fr)
Japanese (ja)
Inventor
正典 佐藤
Original Assignee
三菱電機株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to CN202280088753.5A priority Critical patent/CN118541576A/zh
Priority to PCT/JP2022/002222 priority patent/WO2023139758A1/ja
Priority to US18/719,185 priority patent/US20250067463A1/en
Priority to EP22921915.9A priority patent/EP4467893A4/en
Priority to JP2023575004A priority patent/JPWO2023139758A1/ja
Publication of WO2023139758A1 publication Critical patent/WO2023139758A1/ja

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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
    • F25B13/00—Compression machines, plants or systems, with reversible cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/70—Control systems characterised by their outputs; Constructional details thereof
    • F24F11/80—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air
    • F24F11/83—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers
    • 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
    • F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
    • F25B2313/027—Compression machines, plants or systems with reversible cycle not otherwise provided for characterised by the reversing means
    • F25B2313/02741—Compression machines, plants or systems with reversible cycle not otherwise provided for characterised by the reversing means using one four-way valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/12—Inflammable refrigerants
    • F25B2400/121—Inflammable refrigerants using R1234
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/02—Compressor control
    • 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
    • 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 air conditioner.
  • the present disclosure has been made to solve such problems, and its purpose is to provide an air conditioner with an improved coefficient of performance.
  • An air conditioner includes a refrigerant, a refrigerant circuit, a heat exchanger, and a control device.
  • the refrigerant circuit includes at least a compressor, a condenser, and an evaporator, and is configured to circulate refrigerant.
  • the heat exchanger has a first flow path through which the refrigerant that has passed through the condenser flows and a second flow path through which the refrigerant sucked into the compressor flows, and is configured to exchange heat between the refrigerant passing through the first flow path and the refrigerant passing through the second flow path.
  • the controller is configured to control the refrigerant circuit such that the degree of superheat of the refrigerant flowing through the outlet portion of the evaporator is 5 degrees or less.
  • the air conditioner of the present disclosure can prevent the heat exchange performance of the evaporator from deteriorating when the degree of superheat of the sucked refrigerant is ensured. Therefore, the coefficient of performance of an air conditioner using an internal heat exchanger that exchanges heat between the refrigerant that has passed through the condenser and the refrigerant sucked into the compressor is improved.
  • FIG. 1 is a diagram showing the configuration of an air conditioner 1000 according to Embodiment 1.
  • FIG. FIG. 2 is a diagram showing a comparison of theoretical coefficients of performance (hereinafter referred to as theoretical COP) of air conditioners when various refrigerants are used;
  • FIG. 3 is a PH diagram of a refrigeration cycle device using R290 refrigerant without an internal heat exchanger.
  • FIG. 3 is a PH diagram of a refrigeration cycle device using R290 refrigerant with an internal heat exchanger.
  • FIG. 4 is a diagram showing the relationship between the ratio of R32 in the R32/R1234yf mixed refrigerant and the theoretical COP ratio;
  • FIG. 4 is a diagram showing the relationship between the ratio of R32 in an R32/R1234yf mixed refrigerant, the saturation temperature at standard atmospheric pressure, and the GWP value.
  • FIG. 4 is a diagram showing the relationship between the saturation temperature and theoretical COP ratio of various refrigerants at standard atmospheric pressure.
  • FIG. 3 is a diagram showing the relationship between GWP values and theoretical COP ratios of various refrigerants; It is a figure which shows the modification of the air conditioning apparatus of FIG. 4 is a flowchart for explaining control of an expansion valve 230;
  • FIG. 3 is a diagram showing the configuration of an air conditioner according to Embodiment 2;
  • FIG. 4 is a cross-sectional view showing a specific example of a decompression heat exchanger 270;
  • FIG. 10 is a diagram showing another specific example of the decompression heat exchanger 270;
  • FIG. 12 is a diagram showing a configuration of a modification of the air conditioner of FIG. 11;
  • 3 is a cross-sectional view showing a configuration example of a decompression heat exchanger 280.
  • FIG. 10 is a diagram showing another specific example of the decompression heat exchanger 270;
  • FIG. 12 is a diagram showing a configuration of a modification of the air conditioner of FIG. 11;
  • 3 is a cross-sectional view showing a configuration example of a decompression heat exchanger 280.
  • FIG. 1 is a diagram showing the configuration of an air conditioner 1000 according to Embodiment 1.
  • FIG. An air conditioner 1000 shown in FIG. 1 includes a refrigerant circuit 500, an internal heat exchanger 250, and a control device 100. As shown in FIG.
  • the refrigerant circuit 500 includes at least a compressor 200, an outdoor heat exchanger 210, an expansion valve 230, and an indoor heat exchanger 110, and is configured to circulate refrigerant.
  • refrigerant use is made of a refrigerant having characteristics in a range of GWP values, which will be described later in detail, or in a range of saturation temperatures at standard atmospheric pressure.
  • the refrigerant circuit 500 is composed of a compressor 200, an outdoor heat exchanger 210, an outdoor fan 220, an expansion valve 230, a four-way valve 240, an indoor heat exchanger 110, and an indoor fan 120.
  • the four-way valve 240 has ports P1-P4.
  • an electronic expansion valve LEV: Linear Expansion Valve
  • LEV Linear Expansion Valve
  • the refrigerant circuit 500 is divided into an outdoor unit 1001 and an indoor unit 1002 and arranged.
  • Outdoor unit 1001 includes compressor 200 , four-way valve 240 , outdoor heat exchanger 210 , outdoor fan 220 , expansion valve 230 , controller 100 , and internal heat exchanger 250 .
  • Indoor unit 1002 includes an indoor heat exchanger 110 and an indoor fan 120 . Outdoor unit 1001 and indoor unit 1002 are connected by pipes 310 and 320 .
  • the compressor 200 is configured to change the operating frequency according to a control signal received from the control device 100 .
  • the compressor 200 incorporates an inverter-controlled drive motor whose rotational speed is variable, and the rotational speed of the drive motor changes when the operating frequency is changed.
  • the output of compressor 200 is adjusted.
  • Various types such as rotary type, reciprocating type, scroll type, and screw type can be adopted for the compressor 200 .
  • the four-way valve 240 is controlled by a control signal received from the control device 100 to be in either the cooling operation state or the heating operation state.
  • the cooling operation state as indicated by broken lines, the port P1 and the port P4 are in communication, and the port P2 and the port P3 are in communication.
  • the heating operation state as indicated by solid lines, the port P1 and the port P3 are in communication, and the port P2 and the port P4 are in communication.
  • the internal heat exchanger 250 includes a flow path R1 and a flow path R2.
  • the high-pressure, high-temperature refrigerant that has passed through the condenser (outdoor heat exchanger 210) flows through the flow path R1.
  • the low-pressure, low-temperature refrigerant sucked by compressor 200 flows through flow path R2.
  • internal heat exchanger 250 exchanges heat between the high-pressure, high-temperature refrigerant that has passed through the condenser (outdoor heat exchanger 210) and the low-pressure, low-temperature refrigerant sucked by compressor 200.
  • the air conditioner 1000 further includes temperature sensors 262-265.
  • the temperature sensor 262 is arranged in the indoor heat exchanger 110 and measures a refrigerant temperature T262 which is an evaporation temperature during cooling and a condensation temperature during heating.
  • the temperature sensor 263 is arranged in a pipe connecting the indoor heat exchanger 110 and the port P3 of the four-way valve 240, and measures the refrigerant temperature T263.
  • a temperature sensor 264 is arranged in the outdoor heat exchanger 210 and measures a refrigerant temperature T264, which is the condensation temperature during cooling and the evaporation temperature during heating.
  • the temperature sensor 265 is arranged in a pipe connecting the outdoor heat exchanger 210 and the port P4 of the four-way valve 240, and measures the refrigerant temperature T265.
  • the control device 100 controls the opening degree of the expansion valve 230 so as to adjust the SH (superheat: degree of superheat) of the refrigerant at the outlet of the evaporator according to the outputs of the temperature sensors 262-265.
  • the control device 100 includes a CPU (Central Processing Unit) 101, a memory 102 (ROM (Read Only Memory) and RAM (Random Access Memory)), an input/output buffer (not shown), and the like.
  • the CPU 101 develops a program stored in the ROM into a RAM or the like and executes it.
  • the program stored in the ROM is a program in which processing procedures of the control device 100 are described.
  • the control device 100 controls each device in the air conditioner 1000 according to these programs. This control is not limited to processing by software, and processing by dedicated hardware (electronic circuit) is also possible.
  • the refrigerant circuit of the air conditioner 1000 is composed of the compressor 200, the outdoor heat exchanger 210, the outdoor fan 220, the expansion valve 230, the four-way valve 240, the internal heat exchanger 250, the indoor heat exchanger 110, and the indoor fan 120.
  • Internal heat exchanger 250 performs heat exchange between the high-pressure refrigerant that flows into flow path R1 from the outlet of outdoor heat exchanger 210 during cooling operation and the low-pressure refrigerant that flows into the intake of compressor 200 through flow path R2.
  • FIG. 2 is a diagram showing a comparison of theoretical coefficients of performance (hereinafter referred to as theoretical COP) of air conditioners using various refrigerants.
  • the results in FIG. 2 were obtained by calculating the degree of supercooling (SC) as 0 deg, the evaporation temperature (ET) as 17° C., the condensation temperature (CT) as 40° C., and the compressor efficiency as 1.
  • the theoretical COP of hydrofluorocarbon-based refrigerants decreases as the degree of superheat (SH) of the refrigerant sucked into the compressor increases.
  • the theoretical COP of R290 and R600a which are hydrocarbon refrigerants (hereinafter referred to as HC refrigerants), increases as the degree of superheat (SH) of the sucked refrigerant increases.
  • HFO refrigerants hydrofluoroolefin refrigerants
  • the air conditioner of the present embodiment in addition to controlling the degree of superheat at the evaporator outlet to 5 deg or less, using an internal heat exchanger, and using a low-GWP refrigerant that satisfies certain conditions, it is possible to operate with high air conditioning performance while preventing deterioration in evaporator performance.
  • FIG. 3 is a PH diagram of a refrigeration cycle device using R290 refrigerant without an internal heat exchanger.
  • FIG. 4 is a PH diagram of a refrigeration cycle apparatus using R290 refrigerant with an internal heat exchanger.
  • the theoretical COP is the same as 10.82 for both configurations with and without an internal heat exchanger.
  • the superheat (SH) of the refrigerant at the outlet of the evaporator is equal to the superheat of the refrigerant sucked into the compressor. Therefore, if the degree of superheat of the sucked refrigerant is 10 degrees, the dryness of the refrigerant becomes 1 before the outlet of the evaporator, and the evaporator performance is reduced by the amount of the deterioration of the heat exchange performance of the gas refrigerant portion.
  • the evaporating temperature ET is less than 17° C.
  • a refrigerant that has the characteristic that the theoretical COP increases as the degree of superheat (SH) of the refrigerant sucked into the compressor increases. That is, one generally seeks refrigerants that can improve the actual COP when using an internal heat exchanger. As described with reference to FIG. 2 , with HFC refrigerants, the theoretical COP decreases as the degree of superheat (SH) of the refrigerant sucked into the compressor increases, whereas with HFO refrigerants, the theoretical COP increases as the degree of superheat (SH) of the refrigerant sucked into the compressor increases.
  • R1234yf which is an HFO refrigerant
  • car air conditioners and the like are currently being used in car air conditioners and the like.
  • R32 which is an HFC refrigerant that has been used in home air conditioners
  • FIG. 5 is a diagram showing the relationship between the ratio of R32 in the R32/R1234yf mixed refrigerant and the theoretical COP ratio.
  • the theoretical COP ratio is the ratio of the theoretical COP of the configuration with the internal heat exchanger to the theoretical COP of the configuration without the internal heat exchanger. That is, the theoretical COP ratio value is (theoretical COP for configuration with internal heat exchanger)/(theoretical COP for configuration without internal heat exchanger).
  • Fig. 5 shows the results of calculations assuming that the internal heat exchanger performs 10deg heat exchange at the temperature on the intake side.
  • the mass ratio of R32 exceeds 30%, the effect of improving the theoretical COP when using the internal heat exchanger is lost. That is, the mass ratio range W1 of the R32 refrigerant in which the use of the internal heat exchanger is effective is 0% to 30%.
  • FIG. 6 is a diagram showing the relationship between the R32 ratio of the R32/R1234yf mixed refrigerant, the saturation temperature at standard atmospheric pressure, and the GWP value.
  • the saturation temperature differs depending on the dryness of the refrigerant, even if the pressure is the same, if the refrigerant has a temperature gradient.
  • the results shown in FIG. 6 represent the saturation temperature at standard atmospheric pressure at a dryness of 0.5.
  • the range W1 (0% to 30%) of the mass ratio of the R32 refrigerant that is effective when using the internal heat exchanger obtained in FIG. 5 is applied to FIG. Therefore, if the refrigerant has a saturation temperature of ⁇ 44.4° C. or higher at standard atmospheric pressure, it can be said that the use of the internal heat exchanger is effective. Similarly, if the refrigerant has a GWP of 205 or less, it can be said that there is an effect of using the internal heat exchanger.
  • FIG. 7 is a diagram showing the relationship between the saturation temperature of various refrigerants at standard atmospheric pressure and the theoretical COP ratio.
  • FIG. 8 is a diagram showing the relationship between the GWP values and theoretical COP ratios of various refrigerants.
  • the COP of a configuration without an internal heat exchanger was calculated with a superheat degree (SH) of 10 deg, a supercooling degree (SC) of 0 deg, an evaporation temperature (ET) of 17°C, a condensation temperature (CT) of 40°C, and a compressor efficiency of 1.
  • the COP of the configuration with an internal heat exchanger is the result of calculation assuming that the capacity of the compressor is the same, that the degree of superheat (SH) of the refrigerant at the outlet of the evaporator is controlled to 0 degrees by the expansion valve, and that the internal heat exchanger performs heat exchange equivalent to 10 degrees at the intake side temperature.
  • the saturation temperature range W3 and the GWP value range W4 in which the use of the internal heat exchanger is effective, obtained by applying the range W1 to FIG. 6 generally hold for various refrigerants except R32 and R410A.
  • the refrigerant preferably used in the present embodiment has a characteristic of having a saturation temperature of ⁇ 44.4° C. or higher at standard atmospheric pressure or a GWP of 205 or less. Developers or users of air conditioners can select refrigerants that use these properties as indicators.
  • the internal heat exchanger 250 is installed so that it works mainly during the cooling operation, but there is no problem if it is installed so that it works mainly during the heating operation.
  • an expansion valve may be added as shown in the modification below.
  • FIG. 9 is a diagram showing a modification of the air conditioner of FIG. Air conditioner 1010 shown in FIG. 9 includes refrigerant circuit 510 instead of refrigerant circuit 500 .
  • Refrigerant circuit 510 further includes a second expansion valve 231 inside outdoor unit 1011 with respect to refrigerant circuit 500 .
  • An electronic expansion valve can be used as the expansion valve 231 .
  • Expansion valve 230 is connected between first flow path R ⁇ b>1 of internal heat exchanger 250 and outdoor heat exchanger 210 .
  • control device 100 During cooling operation, the control device 100 fully opens the second expansion valve 231 to control the degree of superheat (SH) of the refrigerant at the evaporator outlet with the expansion valve 230, and during heating operation, fully opens the expansion valve 230 and controls the degree of superheat (SH) of the refrigerant at the evaporator outlet with the second expansion valve 231. By doing so, it is possible to improve the efficiency of heat exchange in the internal heat exchanger 250 in both the cooling operation and the heating operation.
  • SH superheat
  • the internal heat exchanger 250 may be of any type as long as it exchanges heat between the high-pressure refrigerant that has passed through the condenser and the low-pressure refrigerant that is sucked into the compressor.
  • it may be a double-tube heat exchanger composed of an inner tube and an outer tube, or the high-pressure side pipe and the low-pressure side pipe may be soldered to contact each other for heat exchange.
  • the air conditioners shown in FIGS. 1 and 9 are configured to include a four-way valve, the air conditioner may be a cooling-only air conditioner without a four-way valve.
  • the solid line indicates the refrigerant flow during the heating operation mode
  • the dashed line indicates the refrigerant flow during the cooling operation mode.
  • the control device 100 changes the frequency of the compressor 200 so that the indoor temperature reaches the target (set) temperature.
  • FIG. 10 is a flow chart for explaining control of expansion valve 230 .
  • step S21 the control device 100 sets the opening degree of the expansion valve 230 to a prescribed value. After a certain period of time has elapsed, the control device 100 initializes the variable Count to 0 in step S22. Thereafter, in step S23, control device 100 decreases the degree of opening of expansion valve 230 by a constant value. After a certain period of time has passed, in step S24, the control device 100 determines whether the degree of superheat (SH) of the refrigerant at the outlet of the evaporator has changed.
  • SH superheat
  • the evaporator outlet refrigerant superheat (SH) is calculated by subtracting the refrigerant evaporation temperature obtained by the temperature sensor 262 from the evaporator outlet refrigerant temperature obtained by the temperature sensor 263 .
  • the evaporator outlet refrigerant superheat (SH) is calculated by subtracting the refrigerant evaporation temperature obtained by the temperature sensor 264 from the evaporator outlet refrigerant temperature obtained by the temperature sensor 265 .
  • step S24 If it is determined NO in step S24, that is, if there is no change in the evaporator outlet SH, the state of the refrigerant at the evaporator outlet has not changed from the gas-liquid two-phase state. Therefore, in step S25, the control device 100 adds 1 to the variable Count, returns the process to step S23, and decreases the opening of the expansion valve 230 by a constant value.
  • step S24 determines whether the degree of superheat (SH) of the refrigerant at the evaporator outlet is almost zero.
  • step S26 determines whether the degree of superheat (SH) of the refrigerant at the evaporator outlet is appropriately controlled in steps S23 to S25, so the control device 100 ends the processing of this flowchart.
  • the determination in step S26 is YES, the variable Count is 0, so the process of step S24 is passed through without going through step S25.
  • the refrigerant at the outlet of the evaporator is in a superheated gas state, and as a result of the processing in step S23, the refrigerant superheating degree (SH) is further increased, so it cannot be said to be an appropriate state.
  • control device 100 increases the degree of opening of expansion valve 230 by a constant value in step S27. After a certain period of time has passed, the controller 100 determines whether or not there is a change in the degree of superheat (SH) of the refrigerant at the outlet of the evaporator in step S28.
  • SH degree of superheat
  • step S28 If it is determined NO in step S28, that is, if there is a change in the refrigerant superheating degree (SH) at the evaporator outlet, the process returns to step S27 because the refrigerant superheating degree (SH) at the evaporator outlet has changed, and the control device 100 increases the opening degree of the expansion valve 230 by a constant value.
  • step S28 determines whether the degree of superheat (SH) of the refrigerant at the outlet of the evaporator does not change, it can be determined that the refrigerant at the outlet of the evaporator is in a gas-liquid two-phase state (degree of superheat is 0), and the heat exchange efficiency in the evaporator is good, so the control device 100 ends the processing of this flowchart.
  • SH degree of superheat
  • step S21 may take over the opening degree of the expansion valve 230 determined in the previous process.
  • the superheat degree (SH) of the refrigerant at the outlet of the evaporator is controlled to approach the target value (zero), but the target value of the superheat degree (SH) of the refrigerant discharged from the compressor 200 or the target value of the temperature of the discharged refrigerant from the compressor 200 corresponding to the value of the refrigerant superheat (SH) at the evaporator outlet may be determined in advance, and the superheat degree (SH) of the discharged refrigerant or the discharge refrigerant temperature may be controlled to the target value.
  • the expansion valve 231 during the heating operation may be controlled in the same manner as in FIG. 10 by fixing the expansion valve 230 to fully open.
  • the degree of superheat (SH) of the refrigerant changes when there is a pressure loss between the temperature sensors or the refrigerant has a temperature gradient.
  • a refrigerant with a large pressure loss has a small superheat (SH) at the evaporator outlet determined by this method, and a refrigerant with a large temperature gradient has a large refrigerant superheat (SH) at the evaporator outlet determined by this method.
  • the degree of superheat (SH) is about 5 degrees, the performance of the evaporator does not drop so much, so the degree of superheat (SH) should be controlled to 5 degrees or less, so some error is allowed.
  • Embodiment 2. 11 is a diagram showing the configuration of an air conditioner according to Embodiment 2. FIG. Differences from the configuration of FIG. 1 will be described below.
  • An air conditioner 1100 shown in FIG. 11 includes a refrigerant circuit 600 instead of the refrigerant circuit 500 in FIG.
  • Refrigerant circuit 600 includes a decompression heat exchanger 270 inside outdoor unit 1101 instead of internal heat exchanger 250 and expansion valve 230 in the configuration of refrigerant circuit 500 .
  • the decompression heat exchanger 270 includes a low-pressure pipe 271 through which a low-pressure refrigerant flows and a first intermediate-pressure pipe 272 through which an intermediate-pressure refrigerant flows.
  • the first medium-pressure pipe 272 is set to have a smaller inner diameter than the low-pressure pipe 271 .
  • the inner diameter of the first intermediate pressure pipe 272 is set to be smaller than that of the pipes connected to both ends of the intermediate pressure pipe 272 so as to reduce the pressure of the high pressure refrigerant flowing out of the condenser.
  • first low-pressure pipe 271 and the first medium-pressure pipe 272 are in contact with each other so as to exchange heat.
  • the two pipes are brazed with solder or the like and are in contact with each other so as to be able to exchange heat.
  • FIG. 12 is a cross-sectional view showing a specific example of the reduced-pressure heat exchanger 270.
  • the air conditioner is a room air conditioner
  • the pipe diameter of the low-pressure pipe 271 is ⁇ 9.52
  • the pipe diameter of the first medium-pressure pipe 272 is ⁇ 3.0.
  • the diameter of the low-pressure pipe 271 is set large so as to reduce the influence of pressure loss
  • the diameter of the medium-pressure pipe 272 is set small so as to decrease the pressure from high pressure to low pressure.
  • FIG. 13 is a diagram showing another specific example of the reduced-pressure heat exchanger 270.
  • a first medium-pressure pipe 272 is spirally wound around a low-pressure pipe 271 .
  • the contact area of the first medium-pressure pipe 272 with respect to the unit length of the low-pressure pipe 271 is increased, so that the heat exchange efficiency is improved.
  • the length of the low-pressure pipe 271 for obtaining the amount of heat exchange required by the decompression heat exchanger 270 can be shorter than when the medium-pressure pipe 272 is not wrapped around. Since the length of the low-pressure pipe 271 is shortened, there is an effect that the pipe can be easily routed in the machine room. Moreover, since the pressure loss of the low-pressure pipe 271 is also reduced by shortening the length, the pipe diameter of the low-pressure pipe 271 can be reduced.
  • the first medium-pressure pipe 272 is one pipe, but since only one fixed throttle can be realized with one pipe, a structure in which a plurality of pipes are installed in parallel may be used.
  • FIG. 14 is a diagram showing the configuration of a modified example of the air conditioner of FIG.
  • An air conditioner 1110 shown in FIG. 14 includes a refrigerant circuit 601 instead of the refrigerant circuit 600 of FIG.
  • the refrigerant circuit 601 includes a decompression heat exchanger 280 inside the outdoor unit 1111 instead of the decompression heat exchanger 270 in the configuration of the refrigerant circuit 600 .
  • the reduced-pressure heat exchanger 280 further includes a second medium-pressure pipe 273 in addition to the low-pressure pipe 271 and the first medium-pressure pipe 272 .
  • the medium-pressure pipe 272 and the medium-pressure pipe 273 have different pipe diameters.
  • the switching valve 232 may switch the flow path so that the refrigerant passes through a pipe having an optimum inner diameter corresponding to the refrigerant circulation amount, or the pipe through which the refrigerant flows may be changed between the cooling operation and the heating operation.
  • the pipe diameter of the medium-pressure pipe that passes during the heating operation is smaller than the pipe diameter of the medium-pressure pipe that passes during the cooling operation.
  • the temperature difference between the air heat-exchanged by the indoor heat exchanger 110 and the air heat-exchanged by the outdoor heat exchanger 210 is greater during heating operation than during cooling operation, so it is more suitable to increase the throttle amount of the medium pressure piping during heating operation than during cooling operation.
  • JIS Japanese Industrial Standards
  • the air temperature at the entrance of the outdoor heat exchanger 210 is 35°C and the air temperature at the entrance of the indoor heat exchanger 110 is 27°C, so the temperature difference between the two air temperatures is 8°C.
  • the air temperature at the inlet of the indoor heat exchanger 110 is 20°C and the air temperature at the inlet of the outdoor heat exchanger 210 is 7°C, so the temperature difference between the two air temperatures is 13°C.
  • FIG. 15 is a cross-sectional view showing a configuration example of the reduced-pressure heat exchanger 280.
  • the pipe diameters are set so that the medium pressure pipes have different diameters, and are brought into contact with the low pressure pipes so as to exchange heat.
  • the pipe diameter of the low-pressure pipe 271 is ⁇ 9.52
  • the pipe diameter of the first medium-pressure pipe 272 is ⁇ 3.0
  • the pipe diameter of the second medium-pressure pipe 273 is ⁇ 2.5.
  • the diameter of the low-pressure pipe 271 is set large so as to reduce the influence of pressure loss, and the diameters of the medium-pressure pipes 272 and 273 are set small in order to decrease the pressure from high pressure to low pressure.
  • the refrigerant passes through the medium-pressure pipe 273 with a pipe diameter of 2.5 mm during heating operation, and through the medium-pressure pipe 272 with a pipe diameter of 3.0 mm during cooling operation.
  • the air conditioner of Embodiment 2 can always ensure a temperature difference in the heat exchange section in each of cooling operation and heating operation, so that the performance of the air conditioner can be improved in both cooling operation and heating operation. Moreover, since the expansion valve 230 is eliminated, the air conditioner can be constructed at low cost.
  • An air conditioner 1000 shown in FIG. 1 includes a refrigerant, a refrigerant circuit 500, a heat exchanger 250, and a control device 100.
  • Refrigerant circuit 500 includes at least compressor 200, a condenser (outdoor heat exchanger 210), and an evaporator (indoor heat exchanger 110), and is configured to circulate refrigerant.
  • the heat exchanger 250 has a first flow path R1 through which the refrigerant that has passed through the condenser (outdoor heat exchanger 210) flows and a second flow path R2 through which the refrigerant sucked into the compressor 200 flows, and is configured to exchange heat between the refrigerant passing through the first flow path R1 and the refrigerant passing through the second flow path R2.
  • the control device 100 is configured to control the refrigerant circuit 500 so that the degree of superheat of the refrigerant flowing through the outlet portion of the evaporator (indoor heat exchanger 110) is 5 degrees or less.
  • the refrigerant circuit 500 shown in FIG. 1 further includes an expansion valve 230 that expands the refrigerant condensed by the condenser (outdoor heat exchanger 210).
  • Control device 100 changes the degree of superheat of the refrigerant flowing through the outlet portion of the evaporator (indoor heat exchanger 110) by controlling the degree of opening of expansion valve 230 .
  • Refrigerant circuit 500 further includes a four-way valve 240 that changes the direction of refrigerant flow passing through the condenser (outdoor heat exchanger 210) and the evaporator (indoor heat exchanger 110) from the direction during cooling operation so that the refrigerant evaporates in the condenser (outdoor heat exchanger 210) and condenses in the evaporator (indoor heat exchanger 110) during heating operation.
  • the first flow path R1 of the heat exchanger 250 is installed between the condenser (outdoor heat exchanger 210) and the expansion valve 230, and the second flow path R2 of the heat exchanger 250 is installed between the four-way valve 240 and the suction portion of the compressor 200.
  • the pressure of the refrigerant passing through the first flow path (medium pressure piping 272) is higher than the pressure of the refrigerant passing through the second flow path (low pressure piping 271), and the inner diameter of the piping of the first flow path (medium pressure piping 272) is smaller than the inner diameter of the piping of the second flow path (low pressure piping 271).
  • Refrigerant circuit 600 further includes a four-way valve 240 that changes the direction of the flow of refrigerant passing through the condenser (outdoor heat exchanger 210) and the evaporator (indoor heat exchanger 110) from the direction during cooling operation so that the refrigerant evaporates in the condenser (outdoor heat exchanger 210) and condenses in the evaporator (indoor heat exchanger 110) during heating operation.
  • the first flow path (medium pressure pipe 272) of the reduced pressure heat exchanger 270 is installed between the condenser (outdoor heat exchanger 210) and the evaporator (indoor heat exchanger 110).
  • a second flow path (low-pressure pipe 271 ) of the decompression heat exchanger 270 is installed between the four-way valve 240 and the suction portion of the compressor 200 .
  • the first flow path includes a first pipe (medium pressure pipe 272) and a second pipe (medium pressure pipe 273) provided in parallel with the first pipe (medium pressure pipe 272) and having a smaller inner diameter than the first pipe (medium pressure pipe 272).
  • Air conditioner 1110 further includes switching valve 232 that switches whether the refrigerant flows through the first pipe (intermediate pressure pipe 272) or the second pipe (intermediate pressure pipe 273).
  • Control device 100 controls switching valve 232 so that refrigerant flows through the first pipe (intermediate pressure pipe 272) during cooling operation, and refrigerant flows through the second pipe (intermediate pressure pipe 273) during heating operation.
  • the degree of superheat of the refrigerant flowing through the outlet of the evaporator is 0 degrees, and the degree of superheat of the refrigerant sucked by the compressor 200 is greater than 0 degrees.
  • the refrigerant used in the refrigerant circuit 500 has a global warming potential of 205 or less, or a saturation temperature of -44.4°C or higher at standard atmospheric pressure.
  • the refrigerant has a global warming potential of 205 or less and a saturation temperature of -44.4°C or higher at standard atmospheric pressure.
  • the refrigerant contains R32 and R1234yf, and the mass ratio of R32 in the refrigerant is 30% or less.
  • 100 control device 101 CPU, 102 memory, 110 indoor heat exchanger, 120 indoor fan, 200 compressor, 210 outdoor heat exchanger, 220 outdoor fan, 230, 231 expansion valve, 232 switching valve, 240 four-way valve, 250 internal heat exchanger, 262, 263, 264, 265 temperature sensor, 27 0, 280 decompression heat exchanger, 271 low pressure piping, 272, 273 medium pressure piping, 310, 320 piping, 500, 510, 600, 601 refrigerant circuit, 1000, 1010, 1100, 1110 air conditioner, 1001, 1011, 1101, 1111 outdoor unit, 1002 indoor unit, P1, P2, P 3, P4 port, R1 first channel, R2 second channel.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Compression-Type Refrigeration Machines With Reversible Cycles (AREA)
PCT/JP2022/002222 2022-01-21 2022-01-21 空気調和装置 WO2023139758A1 (ja)

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PCT/JP2022/002222 WO2023139758A1 (ja) 2022-01-21 2022-01-21 空気調和装置
US18/719,185 US20250067463A1 (en) 2022-01-21 2022-01-21 Air conditioner
EP22921915.9A EP4467893A4 (en) 2022-01-21 Air conditioner
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WO2025104794A1 (ja) * 2023-11-14 2025-05-22 三菱電機株式会社 空気調和装置

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JPS60108655A (ja) * 1983-11-15 1985-06-14 三洋電機株式会社 ヒ−トポンプ式冷凍装置
JPS63113264A (ja) * 1986-10-30 1988-05-18 三菱電機株式会社 空気調和機
JP2009162388A (ja) * 2007-12-28 2009-07-23 Mitsubishi Electric Corp 冷凍空調装置、冷凍空調装置の室外機および冷凍空調装置の制御装置
JP2019045034A (ja) * 2017-08-31 2019-03-22 株式会社デンソー 冷凍サイクル装置
WO2019198175A1 (ja) * 2018-04-11 2019-10-17 三菱電機株式会社 冷凍サイクル装置
WO2020144764A1 (ja) 2019-01-09 2020-07-16 三菱電機株式会社 冷凍サイクル装置
WO2020188756A1 (ja) * 2019-03-19 2020-09-24 日立ジョンソンコントロールズ空調株式会社 空気調和機

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JPS60108655A (ja) * 1983-11-15 1985-06-14 三洋電機株式会社 ヒ−トポンプ式冷凍装置
JPS63113264A (ja) * 1986-10-30 1988-05-18 三菱電機株式会社 空気調和機
JP2009162388A (ja) * 2007-12-28 2009-07-23 Mitsubishi Electric Corp 冷凍空調装置、冷凍空調装置の室外機および冷凍空調装置の制御装置
JP2019045034A (ja) * 2017-08-31 2019-03-22 株式会社デンソー 冷凍サイクル装置
WO2019198175A1 (ja) * 2018-04-11 2019-10-17 三菱電機株式会社 冷凍サイクル装置
WO2020144764A1 (ja) 2019-01-09 2020-07-16 三菱電機株式会社 冷凍サイクル装置
WO2020188756A1 (ja) * 2019-03-19 2020-09-24 日立ジョンソンコントロールズ空調株式会社 空気調和機

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US20250067463A1 (en) 2025-02-27

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