EP3882536A1 - Klimaanlage - Google Patents

Klimaanlage Download PDF

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Publication number
EP3882536A1
EP3882536A1 EP18940196.1A EP18940196A EP3882536A1 EP 3882536 A1 EP3882536 A1 EP 3882536A1 EP 18940196 A EP18940196 A EP 18940196A EP 3882536 A1 EP3882536 A1 EP 3882536A1
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EP
European Patent Office
Prior art keywords
refrigerant
temperature
outside air
compressor
expansion valve
Prior art date
Legal status (The legal status 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 status listed.)
Pending
Application number
EP18940196.1A
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English (en)
French (fr)
Other versions
EP3882536A4 (de
Inventor
Daisuke Ito
Takumi NISHIYAMA
Kenta MURATA
Tsuyoshi Sato
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Electric Corp
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Mitsubishi Electric Corp
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Filing date
Publication date
Application filed by Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Publication of EP3882536A1 publication Critical patent/EP3882536A1/de
Publication of EP3882536A4 publication Critical patent/EP3882536A4/de
Pending legal-status Critical Current

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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
    • 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
    • F25B1/00—Compression machines, plants or systems with non-reversible cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B13/00—Compression machines, plants or systems, with reversible cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
    • F25B2313/031—Sensor arrangements
    • F25B2313/0314—Temperature sensors near the indoor heat exchanger
    • 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
    • F25B2313/031—Sensor arrangements
    • F25B2313/0315—Temperature sensors near the outdoor heat exchanger
    • 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
    • F25B2500/19—Calculation of parameters
    • 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
    • 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
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/19—Pressures
    • F25B2700/193—Pressures of the compressor
    • F25B2700/1931—Discharge pressures
    • 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
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/19—Pressures
    • F25B2700/193—Pressures of the compressor
    • F25B2700/1933—Suction pressures
    • 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
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2106—Temperatures of fresh outdoor air
    • 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
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2115—Temperatures of a compressor or the drive means therefor
    • F25B2700/21151—Temperatures of a compressor or the drive means therefor at the suction side of the 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
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2115—Temperatures of a compressor or the drive means therefor
    • F25B2700/21152—Temperatures of a compressor or the drive means therefor at the discharge side of the 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
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2116—Temperatures of a condenser

Definitions

  • the present invention relates to an air conditioner.
  • HC refrigerant is known as a refrigerant with a low global warming potential.
  • PTL 1 Japanese Patent Laying-Open No. 11-230626 ) describes a refrigeration cycle apparatus which uses a refrigerant mixture that includes the HC (hydrocarbon) refrigerant. PTL 1 describes that when the refrigerant mixture is used in the refrigeration cycle apparatus, in order to prevent the discharge temperature of the compressor from becoming too high, the opening degree of the expansion valve is adjusted so as to control the discharge temperature equal to or lower than a predetermined temperature.
  • the discharge superheat degree of the compressor may become excessively large while the suction temperature and the suction superheat degree of the compressor may become excessively small.
  • the COP Coefficient Of Performance
  • an object of the present invention is to provide an air conditioner capable of using HC refrigerant with a low global warming potential as a refrigerant and capable of increasing a COP when the HC refrigerant is used higher than that when R32 is used.
  • the air conditioner of the present invention includes: a refrigerant circuit provided with a compressor, a condenser, an expansion valve, and an evaporator, and configured to circulate refrigerant; a first sensor configured to detect a suction temperature of the refrigerant sucked into the compressor; and a second sensor configured to detect an outside air temperature.
  • the refrigerant includes at least one of R290 and R1270.
  • the HC refrigerant with a low global warming potential may be used as a refrigerant, and the COP when the HC refrigerant is used may be made higher than that when R32 is used.
  • Fig. 1 is a diagram illustrating a configuration of an air conditioner according to a first embodiment.
  • the air conditioner includes an outdoor unit 50 and an indoor unit 51.
  • the outdoor unit 50 includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, an expansion valve 4, an outdoor blower 6, an outdoor air temperature sensor 11, a discharge temperature sensor 23, a discharge pressure sensor 24, a suction pressure sensor 22, a suction temperature sensor 21, and a controller 60.
  • the compressor 1 sucks refrigerant, compresses the sucked refrigerant and discharges the compressed refrigerant thereafter.
  • the outdoor heat exchanger 3 functions as a condenser during a cooling operation.
  • the outdoor heat exchanger 3 functions as an evaporator during a heating operation.
  • the expansion valve 4 expands the refrigerant.
  • the expansion valve 4 is an electronic expansion valve, and is configured to change the opening degree (opening area) from zero (full close) to full open stepwise.
  • the outdoor blower 6 blows outdoor air (outside air) to the outdoor heat exchanger 3.
  • the outside air temperature sensor 11 is installed on the air suction side of the outdoor heat exchanger 3 at a position of several centimeters from the housing of the outdoor unit 50.
  • the outside air temperature sensor 11 measures an outside air temperature TO.
  • the discharge temperature sensor 23 detects a discharge temperature TD of the refrigerant discharged from the compressor 1 (hereinafter referred to as the discharge temperature of the compressor 1).
  • the discharge pressure sensor 24 detects a discharge pressure PD of the refrigerant discharged from the compressor 1 (hereinafter referred to as the discharge pressure of the compressor 1). This pressure is the maximum pressure of the refrigerant in the refrigerant circuit 70.
  • the suction pressure sensor 22 detects a suction pressure PS of the refrigerant sucked into the compressor 1 (hereinafter referred to as the suction pressure of the compressor 1). This pressure is the minimum pressure of the refrigerant in the refrigerant circuit 70.
  • the suction temperature sensor 21 detects a suction temperature TS of the refrigerant sucked into the compressor 1 (hereinafter referred to as the suction temperature of the compressor 1).
  • the outdoor heat exchanger temperature sensor 35 measures an evaporation temperature TE of the refrigerant in the outdoor heat exchanger 3 during the heating operation.
  • the outdoor heat exchanger temperature sensor 35 measures a condensation temperature of the refrigerant in the outdoor heat exchanger 3 during the cooling operation.
  • the indoor unit 51 includes an indoor heat exchanger 5 and an indoor blower 7.
  • the indoor heat exchanger 5 functions as an evaporator during the cooling operation.
  • the indoor heat exchanger 5 functions as a condenser during the heating operation.
  • the indoor blower 7 blows indoor air to the indoor heat exchanger 5.
  • the indoor heat exchanger temperature sensor 25 measures a condensation temperature TC of the refrigerant in the indoor heat exchanger 5 during the heating operation.
  • the indoor heat exchanger temperature sensor 25 measures an evaporation temperature of the refrigerant in the indoor heat exchanger 5 during the cooling operation.
  • the refrigerant circuit 70 includes therein the compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the expansion valve 4, and the indoor heat exchanger 5.
  • the four-way valve 2 is a valve provided with four ports a, b, c and d.
  • the port a is connected to a discharge port of the compressor 1 via a pipe P1.
  • the port b is connected to the outdoor heat exchanger 3 via a pipe P2.
  • the port c is connected to a suction port of the compressor 1 via a pipe P3.
  • the port d is connected to the indoor heat exchanger 5 via a pipe P4.
  • the expansion valve 4 is connected to the indoor heat exchanger 5 via a pipe P5.
  • the expansion valve 4 is connected to the outdoor heat exchanger 3 via a pipe P6.
  • Fig. 2 is a diagram illustrating the controller 60 and components connected to the controller 60.
  • the controller 60 receives a signal indicating a detected outside air temperature from the outside air temperature sensor 11.
  • the controller 60 receives a signal indicating a detected discharge temperature from the discharge temperature sensor 23.
  • the controller 60 receives a signal indicating a detected discharge pressure from the discharge pressure sensor 24.
  • the controller 60 receives a signal indicating a detected suction pressure from the suction pressure sensor 22.
  • the controller 60 receives a signal indicating a detected suction temperature from the suction temperature sensor 21.
  • the controller 60 receives a signal indicating a detected temperature of the indoor heat exchanger 5 from the indoor heat exchanger temperature sensor 25.
  • the controller 60 sends a signal to the four-way valve 2 to instruct the switching thereof.
  • the controller 60 sends a signal to the compressor 1 to instruct the start or stop, or a rotation speed thereof.
  • the controller 60 sends a signal to the outdoor blower 6 to instruct the start or stop thereof.
  • the controller 60 sends a signal to the indoor blower 7 to instruct the start or stop thereof.
  • the controller 60 sends a signal to the expansion valve 4 to control the opening degree thereof.
  • the controller 60 is constructed by a processing circuit.
  • the processing circuit may be, for example, a single circuit, a composite circuit, a programmed processor, ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), or a combination thereof.
  • ASIC Application Specific Integrated Circuit
  • FPGA Field Programmable Gate Array
  • the processing circuit is a CPU
  • the function of the controller 60 is realized by software, firmware, or a combination of software and firmware.
  • Software and firmware are written as programs and stored in a memory.
  • the processing circuit realizes a function of the controller 60 by executing a program stored in the memory.
  • the memory may be a nonvolatile or volatile semiconductor memory such as a RAM, a ROM, a flash memory, an EPROM or an EEPROM, or a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, a DVD, or the like.
  • a part of each function of the controller 60 may be realized by dedicated hardware, and a part thereof may be realized by software or firmware.
  • Fig. 3 is a diagram illustrating the flow of refrigerant in the refrigerant circuit 70 during the cooling operation.
  • the controller 60 switches the four-way valve 2 of the refrigerant circuit 70 to a first state.
  • the port a and the port b of the four-way valve 2 communicate with each other, and the port c and the port d of the four-way valve 2 communicate with each other.
  • the refrigerant discharged from the indoor heat exchanger 5 flows into the compressor 1
  • the refrigerant discharged from the compressor 1 flows into the outdoor heat exchanger 3.
  • the controller 60 sets the number of cycles per minute of the compressor 1 and the opening degree of the expansion valve 4 to values suitable for the cooling operation, and starts the compressor 1.
  • the refrigerant circuit 70 operates as follows.
  • the refrigerant is compressed in the compressor 1 into a vapor refrigerant with a high temperature and a high pressure, the high-temperature and high-pressure vapor refrigerant passes through the four-way valve 2 and flows into the outdoor heat exchanger 3.
  • the outdoor heat exchanger 3 functions as a condenser that cools the high-temperature and high-pressure vapor refrigerant during the cooling operation.
  • the high-temperature and high-pressure vapor refrigerant radiates heat to the outdoor air blown by the outdoor blower 6 to the outdoor heat exchanger 3, and thereby is condensed into a high-pressure liquid refrigerant.
  • the high-pressure liquid refrigerant passes through the expansion valve 4, and is depressurized and expanded into a low-temperature and low-pressure gas-liquid two-phase refrigerant, and flows into the indoor heat exchanger 5.
  • the indoor heat exchanger 5 functions as an evaporator that absorbs heat from the depressurized and expanded refrigerant during the cooling operation.
  • the low-temperature and low-pressure gas-liquid two-phase refrigerant absorbs heat from the indoor air blown by the indoor blower 7 to the indoor heat exchanger 5, and thereby is evaporated into a low-pressure vapor refrigerant. Thereafter, the low-pressure vapor refrigerant is sucked into the compressor 1 via the four-way valve 2.
  • the refrigerant is circulated in the refrigerant circuit 70 through the compressor 1, the outdoor heat exchanger 3, the expansion valve 4, and the indoor heat exchanger 5 in this order in the same procedure.
  • Fig. 4 is a diagram illustrating the flow of refrigerant in the refrigerant circuit 70 during the heating operation.
  • the controller 60 switches the four-way valve 2 of the refrigerant circuit 70 to a second state.
  • the port a and the port d of the four-way valve 2 communicate with each other, and the port b and the port c of the four-way valve 2 communicate with each other.
  • the four-way valve 2 is switched to the second state, the refrigerant discharged from the outdoor heat exchanger 3 flows into the compressor 1, and the refrigerant discharged from the compressor 1 flows into the indoor heat exchanger 5.
  • the controller 60 sets the number of cycles per minute of the compressor 1 and the opening degree of the expansion valve 4 respectively to a suitable value for the heating operation, and starts the compressor 1.
  • the refrigerant circuit 70 operates as follows.
  • the refrigerant is compressed in the compressor 1 into a vapor refrigerant with a high temperature and a high pressure, the high-temperature and high-pressure vapor refrigerant passes through the four-way valve 2 and flows into the indoor heat exchanger 5.
  • the indoor heat exchanger 5 functions as a condenser that cools the high-temperature and high-pressure vapor refrigerant during the heating operation.
  • the high-temperature and high-pressure vapor refrigerant radiates heat to the indoor air blown by the indoor blower 7 to the indoor heat exchanger 5, and thereby is condensed into a high-pressure liquid refrigerant.
  • the high-pressure liquid refrigerant passes through the expansion valve 4, and is depressurized and expanded into a low-temperature and low-pressure gas-liquid two-phase refrigerant, and flows into the outdoor heat exchanger 3.
  • the outdoor heat exchanger 3 functions as an evaporator that absorbs heat from the depressurized and expanded refrigerant during the heating operation.
  • the low-temperature and low-pressure gas-liquid two-phase refrigerant absorbs heat from the outdoor air blown by the outdoor blower 6 to the outdoor heat exchanger 3, and thereby is evaporated into a low-pressure vapor refrigerant.
  • the low-pressure vapor refrigerant is sucked into the compressor 1 via the four-way valve 2.
  • the refrigerant is circulated in the refrigerant circuit 70 through the compressor 1, the indoor heat exchanger 5, the expansion valve 4, and the outdoor heat exchanger 3 in this order in the same procedure.
  • the controller 60 calculates a suction superheat degree SHs based on the suction temperature TS and the suction pressure PS. Further, during the heating operation, the controller 60 calculates the suction superheat degree SHs based on the suction temperature TS and the evaporation temperature TE of the refrigerant in the outdoor heat exchanger 3.
  • the controller 60 calculates a discharge superheat degree SHd based on the discharge temperature TD and the discharge pressure Pd. During the heating operation, the controller 60 calculates the discharge superheat degree SHd based on the discharge temperature TD and the condensation temperature TC of the refrigerant in the indoor heat exchanger 4.
  • the controller 60 controls the number of cycles per minute of the compressor 1 and a rotation speed of the outdoor blower 6 based on the outside air temperature TO.
  • HC refrigerant such as R290 (GWP4) or R1270 instead of an HFC refrigerant such as R410A (GWP2088) or R32 (GWP675).
  • R290 has a latent heat of condensation that is 1.2 times greater than R32, and has a larger refrigeration effect that is exhibited by an enthalpy difference between an inlet and an outlet of the condenser with respect to an increase in the suction superheat degree SHs. Therefore, if the suction superheat degree SHs is the same, the circulation amount of refrigerant R290 required to reach a certain capacity is only 0.8 times of the circulation amount of refrigerant R32. As a result, when R290 is used, the theoretical compression work of the compressor 1 becomes smaller, and thereby the theoretical COP becomes higher than the case when R32 is used.
  • Fig. 5 is a diagram illustrating the relationship between the suction superheat degree SHs and the theoretical COP.
  • the refrigerant circulated in the refrigerant circuit 70 includes at least one of R290 and R1270, each of which is a flammable natural HC refrigerant with a low GWP.
  • the refrigerant flowing in the refrigerant circuit 70 is R290 alone, R1270 alone, or a mixed refrigerant containing at least one of R290 and R1270 as a main component.
  • the conventional air conditioner that uses R32 is configured to operate while performing a control on the discharge temperature TD by reducing the suction superheat degree SHs of the compressor 1 so as to prevent the discharge temperature TD from increasing.
  • the discharge superheat degree SHd may become excessively large, and the suction temperature TS and the suction superheat degree SHs may become excessively small, which may deteriorate the COP.
  • the theoretical COP of R290 is higher than that of R32, it is difficult to obtain a COP in the case where R290 is used equal to or higher than that in the case where R32 is used by the conventional control.
  • paraffin-based hydrocarbons such as R290 or R1270 for the safety purpose according to the regulations on filling amount of refrigerant (IEC 60335-2-40).
  • these lubricating oils are not suitable for a typical high-pressure hermetic air conditioner because of their low viscosity.
  • an oil which has a density higher than that of the refrigerant such as polyalkylene glycol-based PAG or polyvinyl ether-based PVE having an ether bond, or polyol ester-based POE having an ester bond is used as the lubricating oil of the compressor 1. Since PAG has low compatibility with R290, when R290 is used as the refrigerant, PAG is preferably used as the lubricating oil for R290.
  • the compressor 1, the four-way valve 2, and the expansion valve 4 are connected to each other by refrigerant pipes in a machine chamber of the outdoor unit 50. These components are covered with a front panel, side panels, a rear panel and partition plates, each of which is made of a metal plate, and are separated from the outside air. Therefore, due to the heat radiated from the compressor 1, the ambient air temperature in the machine chamber may be higher than the outside air temperature TO. Due to the overheating by the ambient air in the machine chamber and the heat absorbed from the refrigerant which is discharged from the four-way valve 2 at the discharge temperature TD, the suction temperature TS may be higher than the outside air temperature TO.
  • Fig. 6 is a diagram illustrating the relationship between an outside air temperature TO and a normalized COP.
  • the normalized COP represents a ratio of the COP at each temperature to the COP at an outside air temperature TO of 12°C.
  • the COP(B) at the outside air temperature TO of 2°C and the COP(C) at the outside air temperature TO of 7°C contribute a greater part to the SCOP.
  • the contribution of the COP(B) at the outside air temperature TO of 2°C and the COP(C) at the outside air temperature TO of 7°C to the SCOP is 74%.
  • the contribution of the COP(B) at the outside air temperature TO of 2°C, the COP(C) at the outside air temperature TO of 7°C, and the COP(D) at the outside air temperature TO of 12°C to the SCOP is 83%.
  • the COP of the air conditioner changes linearly in response to the outside air temperature TO.
  • the SCOP of the air conditioner is generally determined.
  • the heating operation in the case where the outside air temperature TO is below zero involves a defrosting operation, the actual COP may be different from the theoretical COP. Therefore, in the present embodiment, three outside air temperatures TO of 2°C, 7°C and 12°C among the outside air temperatures TO of -7°C, 2°C, 7°C and 12°C that are used to determine the SCOP will be discussed.
  • Figs. 7(a) to 7(c) are diagrams illustrating a relationship between the suction temperature TS and the normalized COP for R290 and R32.
  • Figs. 7(a) to 7(c) illustrate the relationship between the suction temperature TS and the normalized COP when the suction superheat degree SHs for determining the SCOP changes from 0.1°C to 20°C at the outside air temperature TO of 2°C, 7°C, and 12°C, respectively.
  • the suction superheat degree SHs is 0.1°C
  • the suction temperature TS is minimum.
  • the suction superheat degree SHs is 20°C
  • the suction temperature TS is maximum.
  • the COP of R32 when the suction superheat degree SHs is 0.1°C is denoted by X
  • the normalized COP is represented by (COP/X) ⁇ 100.
  • Horizontal straight lines LI, L2 and L3 in Figs. 7(a) to 7(c) indicate a lower limit of a COP so as to achieve an SCOP equivalent to the COP of R32 at another outside air temperature TO.
  • the lower limit represented by L1 and L2 is 97%; and when the outside air temperature TO is 12°C, the lower limit represented by L3 is 93%.
  • the COP of the air conditioner may be improved by using R290 instead of R32.
  • the suction temperature TS becomes smaller than 0°C, the suction pipe is frosted, which significantly reduces the COP.
  • the COP of the air conditioner may be improved by using R290 instead of R32.
  • the COP of the air conditioner may be improved by using R290 instead of R32.
  • R290 instead of R32 in the air conditioner at a higher COP despite the outside air temperature TO.
  • ⁇ T TS-TO
  • W -2.0°C to +0.6°C
  • Fig. 8 is a flowchart illustrating a control process during a heating operation of the air conditioner according to the first embodiment.
  • step S301 the discharge temperature sensor 23 detects a discharge temperature TD of the compressor 1.
  • the controller 60 receives a signal indicating the discharge temperature TD of the compressor 1 from the discharge temperature sensor 23.
  • step S302 the suction temperature sensor 21 detects a suction temperature TS of the compressor 1.
  • the controller 60 receives a signal indicating the detected suction temperature TS from the suction temperature sensor 21.
  • step S104 If it is determined that the temperature difference ⁇ T is less than (-2.0°C) in step S104 (YES in S104), the process proceeds to step S105. If it is determined that the temperature difference ⁇ T is greater than (+0.6°C) in step S106 (YES in S106), the process proceeds to step S107. If it is determined that the temperature difference ⁇ T is not less than (-2.0°C) and not greater than (+0.6°C) (NO in S104 and NO in S106), the process ends.
  • step S105 the controller 60 decreases the opening degree of the expansion valve 4 by a predetermined amount. Thereafter, the process returns to step S101.
  • step S107 the controller 60 increases the opening degree of the expansion valve 4 by a predetermined amount. Thereafter, the process returns to step S101.
  • the controller 60 controls the expansion valve 4 so as to make the suction temperature TS equal to the outside air temperature TO.
  • Fig. 9 is a flowchart illustrating a control process on the air conditioner during the heating operation according to a second embodiment.
  • step S201 the outside air temperature sensor 11 detects an outside air temperature TO.
  • the controller 60 receives a signal indicating the outside air temperature TO from the outside air temperature sensor 11.
  • step S202 the suction temperature sensor 21 detects a suction temperature TS of the compressor 1.
  • the controller 60 receives a signal indicating the suction temperature TS from the suction temperature sensor 21.
  • step S203 If it is determined that the suction temperature TS is lower than the outside air temperature TO in step S203 (YES in S203), the process proceeds to step S204. If it is determined that the suction temperature TS is greater than the outside air temperature TO in step S205 (YES in S205), the process proceeds to step S206. If it is determined that the suction temperature TS is equal to the outside air temperature TO (NO in S203 and NO in S205), the process ends.
  • step S204 the controller 60 decreases the opening degree of the expansion valve 4 by a predetermined amount. Thereafter, the process returns to step S101.
  • step S206 the controller 60 increases the opening degree of the expansion valve 4 by a predetermined amount. Thereafter, the process returns to step S101.
  • the air conditioner may be operated at an evaporation temperature TE that is lower than the outside air temperature TO, while in the present embodiment, the outside air temperature TO is controlled equal to the suction temperature TS, which means that the evaporation temperature TE is lower than the suction temperature TS.
  • Figs. 10(a) to 10(c) are diagrams illustrating the relationship between the discharge superheat degree SHd and the normalized COP for R290 and R32.
  • Figs. 10(a) to 10(c) illustrate the relationship between the discharge superheat degree SHd and the normalized COP at the outside air temperature TO of 2°C, 7°C, and 12°C, respectively, when the suction superheat degree SHs, which is used to determine the SCOP, changes from 0.1°C to 20°C.
  • the suction superheat degree SHs is 0.1°C
  • the discharge superheat degree SHd is minimum.
  • the suction superheat degree SHs is 20°C
  • the discharge superheat degree SHd is maximum.
  • the normalized COP is represented by (COP/X) ⁇ 100.
  • the discharge superheat degree SHd of R290 having a COP higher than that of R32 at an outside air temperature TO is smaller than that of R32.
  • Fig. 11 is a diagram illustrating a range of discharge superheat degrees SHd in which the COP of R290 is higher than the COP of R32 and no liquid back phenomenon occurs in the compressor 1.
  • the straight line R1 is expressed by the formula (2)
  • the straight line R2 is expressed by the formula (3).
  • the COP of R290 is higher than the COP of R32, and no liquid back phenomenon occurs in the compressor 1.
  • the range of discharge superheat degrees SHd in which the air conditioner may be operated at a higher COP when R290 is used becomes smaller than the range when R32 is used.
  • the controller 60 controls the opening degree of the expansion valve 4 based on the outside air temperature TO such that the discharge superheat degree SHd is equal to or greater than L(SHd) represented by the formula (3) and equal to or less than U(SHd) represented by the formula (2).
  • Fig. 12 is a flowchart illustrating a control process on the air conditioner during the heating operation according to a third embodiment.
  • step S300 the outside air temperature sensor 11 detects an outside air temperature TO.
  • the controller 60 receives a signal indicating the outside air temperature TO from the outside air temperature sensor 11.
  • step S301 the outside air temperature sensor 11 detects an outside air temperature TO.
  • the controller 60 receives a signal indicating the outside air temperature TO from the outside air temperature sensor 11.
  • step S302 the indoor heat exchanger temperature sensor 25 detects a condensation temperature TC of the refrigerant in the indoor heat exchanger 5.
  • the controller 60 receives a signal indicating the condensation temperature TC of the refrigerant from the indoor heat exchanger temperature sensor 25.
  • step S304 the controller 60 calculates U(SHd) from the outside air temperature TO by the formula (2) mentioned in the above.
  • step S304 the controller 60 calculates L(SHd) from the outside air temperature TO by the formula (3) mentioned in the above.
  • step S305 If it is determined that the discharge superheat degree SHd is less than L(SHd) in step S305 (YES in S305), the process proceeds to step S307. If it is determined that the discharge superheat degree SHd is greater than U(SHd) in step S308 (YES in S308), the process proceeds to step S309. If it is determined that the discharge superheat degree SHd is not less than L(SHd) and not greater than U(SHd) (NO in S305 and NO in S308), the process ends.
  • step S307 the controller 60 decreases the opening degree of the expansion valve 4 by a predetermined amount. Thereafter, the process returns to step S301.
  • step S309 the controller 60 increases the opening degree of the expansion valve 4 by a predetermined amount. Thereafter, the process returns to step S301.
  • R290 instead of R32 in the air conditioner at a higher COP.
  • the control may be made finely in response to the change in the outside air temperature TO, more energy may be saved as compared with the conventional control on the discharge temperature.
  • the same effect may be achieved by using R1270 which has properties such as the boiling point and the operating pressure similar to that of R290.
  • the ratio of the refrigerant dissolved in the PAG may be limited to 30% or less.
  • the refrigerant filling amount may be made equal to or less than an allowable refrigerant amount.
  • R1270 which has properties such as the boiling point and the operating pressure similar to that of R290.
  • the present invention is not limited to the embodiments described above, and may include, for example, the following modifications.
  • the controller adjusts the opening degree of the expansion valve by a predetermined amount, but the present invention is not limited thereto.
  • the controller may be configured to adjust the opening degree of the expansion valve by an amount in proportion to the magnitude of the difference between ⁇ T and (-2.0) or the magnitude of the difference between ⁇ T and (+0.6).
  • controller adjusts the opening degree of the expansion valve by a predetermined amount, but the present invention is not limited thereto.
  • the controller may be configured to adjust the opening degree of the expansion valve by an amount in proportion to the magnitude of the difference between TS and TO.
  • the controller adjusts the opening degree of the expansion valve by a predetermined amount, but the present invention is not limited thereto.
  • the controller may be configured to adjust the opening degree of the expansion valve by an amount in proportion to the magnitude of the difference between SHd and L(SHd) or the magnitude of the difference between SHd and U(SHd).
  • ⁇ T suction temperature TS-outside air temperature TO
  • W -2.0°C to +4.6°C
  • the controller may decrease the opening degree of the expansion valve by a predetermined amount when ⁇ T is less than (-2.0), and increase the opening degree of the expansion valve by a predetermined amount when ⁇ T is greater than (+4.6).
  • the controller may be configured to control the expansion valve such that ⁇ T is within the range W (-4.0°C to +0.6°C) when the outside air temperature TO is 7°C. In other words, if the outside air temperature TO is 7°C, the controller may decrease the opening degree of the expansion valve by a predetermined amount when ⁇ T is less than (-4.0), and increase the opening degree of the expansion valve by a predetermined amount when ⁇ T is greater than (0.6).
  • the controller may be configured to control the expansion valve such that ⁇ T is within the range W (-2.6°C to +1.6°C) when the outside air temperature TO is 12°C.
  • the controller may decrease the opening degree of the expansion valve by a predetermined amount when ⁇ T is less than (-2.6), and increase the opening degree of the expansion valve by a predetermined amount when ⁇ T is greater than (+1.6).
  • the controller may determine an upper limit and a lower limit of the range W by linear interpolation.

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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)
EP18940196.1A 2018-11-14 2018-11-14 Klimaanlage Pending EP3882536A4 (de)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2018/042112 WO2020100228A1 (ja) 2018-11-14 2018-11-14 空気調和機

Publications (2)

Publication Number Publication Date
EP3882536A1 true EP3882536A1 (de) 2021-09-22
EP3882536A4 EP3882536A4 (de) 2021-11-17

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EP18940196.1A Pending EP3882536A4 (de) 2018-11-14 2018-11-14 Klimaanlage

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EP (1) EP3882536A4 (de)
JP (1) JP7019070B2 (de)
CN (1) CN112955701B (de)
RU (1) RU2769213C1 (de)
WO (1) WO2020100228A1 (de)

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02171553A (ja) * 1988-12-23 1990-07-03 Matsushita Refrig Co Ltd 能力可変空気調和機
JP3054564B2 (ja) * 1994-11-29 2000-06-19 三洋電機株式会社 空気調和機
JPH1019391A (ja) * 1996-06-28 1998-01-23 Daikin Ind Ltd 空気調和機の制御装置
JPH11230626A (ja) * 1998-02-12 1999-08-27 Matsushita Electric Ind Co Ltd 冷凍サイクル装置
JP2003279170A (ja) * 2002-03-20 2003-10-02 Sanyo Electric Co Ltd 空気調和装置
JP2010038463A (ja) * 2008-08-06 2010-02-18 Panasonic Corp 冷凍サイクル装置
EP2410263A4 (de) * 2009-03-19 2015-03-25 Daikin Ind Ltd Klimaanlage
CN103958986B (zh) 2011-11-29 2016-08-31 三菱电机株式会社 冷冻空调装置
EP2813784B1 (de) * 2011-12-22 2019-08-07 Mitsubishi Electric Corporation Klimaanlage
WO2015136651A1 (ja) * 2014-03-12 2015-09-17 三菱電機株式会社 空気調和装置
JP6316452B2 (ja) * 2014-11-26 2018-04-25 三菱電機株式会社 冷凍サイクル装置
US10563877B2 (en) * 2015-04-30 2020-02-18 Daikin Industries, Ltd. Air conditioner
JP6467011B2 (ja) * 2017-09-25 2019-02-06 三菱電機株式会社 空調機

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CN112955701A (zh) 2021-06-11
EP3882536A4 (de) 2021-11-17
JP7019070B2 (ja) 2022-02-14
WO2020100228A1 (ja) 2020-05-22
RU2769213C1 (ru) 2022-03-29
CN112955701B (zh) 2022-08-23
JPWO2020100228A1 (ja) 2021-09-02

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