WO2024070872A1 - Air conditioner - Google Patents

Air conditioner Download PDF

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Publication number
WO2024070872A1
WO2024070872A1 PCT/JP2023/034206 JP2023034206W WO2024070872A1 WO 2024070872 A1 WO2024070872 A1 WO 2024070872A1 JP 2023034206 W JP2023034206 W JP 2023034206W WO 2024070872 A1 WO2024070872 A1 WO 2024070872A1
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WIPO (PCT)
Prior art keywords
refrigerant
heat exchanger
liquid
gas
way valve
Prior art date
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PCT/JP2023/034206
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French (fr)
Japanese (ja)
Inventor
智充 山口
恵介 三苫
誠心 沖野
裕介 土井
道明 中西
峻也 楠本
優好 平沢
泰明 兼子
Original Assignee
三菱重工サーマルシステムズ株式会社
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Application filed by 三菱重工サーマルシステムズ株式会社 filed Critical 三菱重工サーマルシステムズ株式会社
Publication of WO2024070872A1 publication Critical patent/WO2024070872A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F1/00—Room units for air-conditioning, e.g. separate or self-contained units or units receiving primary air from a central station
    • F24F1/0003—Room units for air-conditioning, e.g. separate or self-contained units or units receiving primary air from a central station characterised by a split arrangement, wherein parts of the air-conditioning system, e.g. evaporator and condenser, are in separately located units
    • 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
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
    • F25B41/26—Disposition of valves, e.g. of on-off valves or flow control valves of fluid flow reversing 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

Definitions

  • the refrigeration cycle includes an evaporator, a condenser, a compressor, and an expansion valve.
  • the refrigerant flows through the compressor, condenser, expansion valve, and evaporator in that order.
  • the liquid-phase refrigerant and the gas-phase refrigerant In order to ensure thermal efficiency, it is desirable for the liquid-phase refrigerant and the gas-phase refrigerant to flow in opposite directions in a countercurrent state within the liquid-gas heat exchanger. Therefore, in the device described in Patent Document 1 below, the direction of the refrigerant flowing into the liquid-gas heat exchanger can be appropriately changed by a four-way valve between cooling operation and heating operation.
  • This disclosure has been made to solve the above problems, and aims to provide an air conditioner with improved operating efficiency.
  • the air conditioner according to the present disclosure comprises a refrigeration cycle having an outdoor heat exchanger, an indoor heat exchanger, a compressor, and an expansion valve through which a refrigerant flows in sequence, a first four-way valve that enables heating operation and cooling operation by switching the flow direction of the refrigerant, a liquid-gas heat exchanger that exchanges heat between a gas refrigerant on the low pressure side of the refrigeration cycle and a liquid refrigerant on the high pressure side, and a second four-way valve that switches the flow of the refrigerant so that the gas refrigerant and the liquid refrigerant flow in counter directions in the liquid-gas heat exchanger in both the heating operation and the cooling operation, and the second four-way valve is disposed in an area through which the gaseous refrigerant on the low pressure side of the refrigeration cycle flows.
  • the air conditioner according to the present disclosure comprises a refrigeration cycle having an outdoor heat exchanger, an indoor heat exchanger, a compressor, and an expansion valve through which a refrigerant flows in sequence; a first four-way valve that enables heating operation and cooling operation by switching the flow direction of the refrigerant; a liquid-gas heat exchanger that exchanges heat between a gas refrigerant on the low pressure side of the refrigeration cycle and a liquid refrigerant on the high pressure side; a second four-way valve that switches the flow of the refrigerant so that the gas refrigerant and the liquid refrigerant flow in countercurrent flow in the liquid-gas heat exchanger in both the heating operation and the cooling operation; and an accumulator that is provided upstream of the compressor and separates the refrigerant into gas and liquid, and the liquid-gas heat exchanger is disposed between the accumulator and the compressor.
  • This disclosure makes it possible to provide an air conditioner with improved operating efficiency.
  • FIG. 2 is a circuit diagram of the air conditioner according to the first embodiment of the present disclosure, illustrating the flow of refrigerant during cooling operation.
  • FIG. 2 is a circuit diagram of the air conditioner according to the first embodiment of the present disclosure, showing the flow of refrigerant during heating operation.
  • FIG. 11 is a circuit diagram of an air conditioner according to a second embodiment of the present disclosure, illustrating the flow of refrigerant during cooling operation.
  • FIG. 11 is a circuit diagram of an air conditioner according to a second embodiment of the present disclosure, illustrating the flow of refrigerant during heating operation.
  • FIG. 11 is a circuit diagram showing a modified example of the air conditioner according to the second embodiment of the present disclosure.
  • the air conditioner 1 is a device that is installed in a building such as a house or in transportation machinery such as an automobile, and adjusts the indoor temperature to a specified value.
  • the air conditioner 1 includes a refrigeration cycle 10, a first four-way valve 20, a liquid-gas heat exchanger 30, and a second four-way valve 40.
  • the refrigeration cycle 10 is a circuit for performing heat exchange between the indoor air and the refrigerant, and between the outdoor air and the refrigerant, by compressing and expanding the refrigerant that flows through each device of the refrigeration cycle 10 in sequence.
  • the refrigeration cycle 10 has an indoor heat exchanger 11, an indoor fan 12, an outdoor heat exchanger 13, an outdoor fan 14, a compressor 15, an accumulator 16, a first expansion valve 17 (expansion valve), a second expansion valve 18 (expansion valve), a first flow path 51, a second flow path 52, a compressor flow path 53, and a low-pressure gas flow path 54.
  • the indoor heat exchanger 11 is disposed on the first flow path 51.
  • the first flow path 51 is a flow path that connects between the first four-way valve 20 and the liquid-gas heat exchanger 30, which will be described later.
  • the inside of the first flow path 51 is filled with a refrigerant.
  • the indoor heat exchanger 11 exchanges heat between the refrigerant flowing through the first flow path 51 and the indoor air.
  • the indoor heat exchanger 11 is, for example, a fin-and-tube type heat exchanger.
  • An indoor fan 12 is provided near the indoor heat exchanger 11. By operating the indoor fan 12, the indoor air is forcibly supplied to the indoor heat exchanger 11.
  • a first expansion valve 17 is disposed on the first flow path 51 at a position on the liquid-gas heat exchanger 30 side of the indoor heat exchanger 11.
  • the first expansion valve 17 is, for example, an electromagnetic expansion valve, and its opening is adjusted by an electrical signal sent from the outside.
  • the first expansion valve 17 is used to expand the refrigerant flowing in the first flow path 51 during cooling operation, thereby reducing its pressure.
  • the outdoor heat exchanger 13 is disposed on the second flow path 52.
  • the second flow path 52 is a flow path that connects the first four-way valve 20 and the liquid-gas heat exchanger 30, and is a flow path provided separately from the first flow path 51.
  • the second flow path 52 is filled with a refrigerant.
  • the outdoor heat exchanger 13 exchanges heat between the refrigerant flowing through the second flow path 52 and the outdoor air.
  • the outdoor heat exchanger 13 is, for example, a fin-and-tube type heat exchanger.
  • An outdoor fan 14 is provided near the outdoor heat exchanger 13. By operating the outdoor fan 14, outdoor air is forcibly supplied to the outdoor heat exchanger 13.
  • a second expansion valve 18 is disposed on the second flow path 52 at a position on the liquid-gas heat exchanger 30 side of the outdoor heat exchanger 13.
  • the second expansion valve 18 is, for example, an electromagnetic expansion valve, and its opening is adjusted by an electrical signal sent from the outside.
  • the second expansion valve 18 is used to expand the refrigerant flowing in the second flow path 52 during heating operation, thereby reducing its pressure.
  • the compressor 15 and the accumulator 16 are provided on the compressor flow path 53.
  • the compressor flow path 53 is a flow path that connects the liquid-gas heat exchanger 30 and the first four-way valve 20, and is a flow path different from the first flow path 51 and the second flow path 52 described above.
  • the compressor 15 compresses the gas refrigerant in the compressor flow path 53 to generate a high-temperature, high-pressure gas refrigerant.
  • a scroll compressor or a rotary compressor is preferably used as the compressor 15.
  • the accumulator 16 is disposed adjacent to the upstream side of the compressor 15 on the compressor flow path 53.
  • the accumulator 16 separates the refrigerant into gas and liquid, sends only the gas phase component to the compressor 15, and stores the liquid phase component.
  • the liquid phase component stored in the accumulator 16 also contains lubricating oil mixed with the refrigerant.
  • the low-pressure gas flow path 54 connects the first four-way valve 20 and the liquid-gas heat exchanger 30 in parallel with the compressor flow path 53.
  • the second four-way valve 40 which will be described later, is disposed on the low-pressure gas flow path 54.
  • the first four-way valve 20 switches the flow direction of the refrigerant by switching the connection state of the first flow path 51, the second flow path 52, the compressor flow path 53, and the low-pressure gas flow path 54.
  • Fig. 1 shows the open state of the first four-way valve 20 during cooling operation. Specifically, the compressor flow path 53 and the second flow path 52 are connected, and the first flow path 51 and the low-pressure gas flow path 54 are connected. The state during heating operation will be described later with reference to Fig. 2.
  • the liquid-gas heat exchanger 30 is provided at a position connecting an end of the first flow path 51 on the first expansion valve 17 side and an end of the second flow path 52 on the second expansion valve 18 side.
  • the liquid-gas heat exchanger 30 also connects the low-pressure gas flow path 54 and the compressor flow path 53.
  • heat is exchanged between a high-temperature, high-pressure liquid refrigerant flowing from the second flow path 52 to the first flow path 51 and a low-temperature, low-pressure gas refrigerant flowing from the low-pressure gas flow path 54 to the compressor flow path 53.
  • the flow directions of these two refrigerants are determined so that they flow in opposite directions to each other, that is, so that they flow in countercurrents.
  • the second four-way valve 40 switches the flow of refrigerant so that the two refrigerant flows in the liquid-gas heat exchanger 30 are counterflows both during heating operation and cooling operation. Specifically, the second four-way valve 40 switches the open states of the low-pressure gas flow path 54 and the compressor flow path 53, and the liquid-gas heat exchanger 30. During cooling operation as shown in Fig. 1, the refrigerant that has passed through the low-pressure gas flow path 54 passes through the liquid-gas heat exchanger 30 and heads toward the compressor flow path 53. At this time, the open state of the second four-way valve 40 is switched so that the flow direction of the refrigerant is opposite to the flow direction of the refrigerant from the second flow path 52 toward the first flow path 51.
  • the second four-way valve 40 is provided in an area where low-pressure gas refrigerant normally flows (i.e., on the low-pressure gas flow path 54). In other words, it is preferable that the second four-way valve 40 is provided between the indoor heat exchanger 11 and the compressor 15. More preferably, the second four-way valve 40 is provided between the first four-way valve 20 and the liquid-gas heat exchanger 30.
  • FIG. 1 shows the circuit state of the air conditioner 1 during cooling operation.
  • the gas refrigerant compressed by the compressor 15 to a high temperature and high pressure passes through the first four-way valve 20 and flows to the outdoor heat exchanger 13 on the second flow path 52.
  • the gas refrigerant that has exchanged heat with outdoor air in the outdoor heat exchanger 13 becomes a high-pressure liquid refrigerant.
  • This refrigerant then passes through the second expansion valve 18 on the second flow path 52. Note that the second expansion valve 18 is fully open during cooling operation, and the pressure of the refrigerant does not change even when it passes through the second expansion valve 18.
  • the refrigerant that has passed through the second flow path 52 flows into the liquid-gas heat exchanger 30.
  • the high-temperature, high-pressure liquid refrigerant that has passed through the second flow path 52 exchanges heat with the low-temperature, low-pressure gas refrigerant described below.
  • the refrigerant that passes through the liquid-gas heat exchanger 30 and flows into the first flow path 51 drops in temperature and becomes in a state of increased subcooling.
  • the refrigerant in the subcooled state then passes through the first expansion valve 17.
  • the refrigerant expands and becomes a low-temperature, low-pressure liquid refrigerant.
  • the refrigerant that has flowed into the indoor heat exchanger 11 then exchanges heat with the indoor air, causing its temperature to rise and it to evaporate, becoming a low-pressure gas refrigerant.
  • the low-pressure gas refrigerant passes through the first four-way valve 20 and flows into the low-pressure gas flow path 54.
  • This low-pressure gas refrigerant then passes through the second four-way valve 40 and exchanges heat with the high-temperature, high-pressure liquid refrigerant described above in the liquid-gas heat exchanger 30. This causes the low-pressure gas refrigerant to become superheated.
  • the superheated low-pressure gas refrigerant passes through the second four-way valve 40 again, and then flows into the accumulator 16 and compressor 15. The above cycle occurs continuously, causing the air conditioner 1 to operate in cooling mode.
  • the gas refrigerant compressed by the compressor 15 to a high temperature and high pressure flows through the first four-way valve 20 to the indoor heat exchanger 11 on the first flow path 51.
  • the gas refrigerant becomes a high-pressure liquid refrigerant.
  • This refrigerant then passes through the first expansion valve 17 on the first flow path 51. Note that the first expansion valve 17 is fully open during heating operation, and there is no change in the pressure of the refrigerant even when it passes through the first expansion valve 17.
  • the refrigerant that has passed through the first flow path 51 then flows into the liquid-gas heat exchanger 30.
  • the high-temperature, high-pressure liquid refrigerant that has passed through the first flow path 51 exchanges heat with a low-temperature, low-pressure gas refrigerant, which will be described later.
  • the refrigerant that passes through the liquid-gas heat exchanger 30 and flows into the second flow path 52 has a lower temperature and a higher degree of subcooling.
  • the subcooled refrigerant then passes through the second expansion valve 18.
  • the refrigerant expands and becomes a low-temperature, low-pressure liquid refrigerant.
  • the refrigerant that has flowed into the outdoor heat exchanger 13 then exchanges heat with the outdoor air, causing its temperature to rise and it to evaporate, becoming a low-pressure gas refrigerant.
  • the low-pressure gas refrigerant passes through the first four-way valve 20 and flows into the low-pressure gas flow path 54.
  • This low-pressure gas refrigerant then passes through the second four-way valve 40 and exchanges heat with the high-temperature, high-pressure liquid refrigerant described above in the liquid-gas heat exchanger 30. This causes the low-pressure gas refrigerant to become superheated.
  • the superheated low-pressure gas refrigerant passes through the second four-way valve 40 again, and then flows into the accumulator 16 and compressor 15. The above cycle occurs continuously, causing the air conditioner 1 to operate in heating mode.
  • the refrigerant returning to the compressor 15 from the indoor heat exchanger 11 or the outdoor heat exchanger 13 as an evaporator is a gas refrigerant with the lowest possible temperature to prevent liquid compression in the compressor 15.
  • the liquid-gas heat exchanger 30 there is also a demand to suppress the generation of flash gas by supercooling the refrigerant in the refrigerant piping. Therefore, in the air conditioner 1 according to this embodiment, these two demands are met by the liquid-gas heat exchanger 30. Specifically, by using the liquid-gas heat exchanger 30, heat exchange can be performed between a high-temperature, high-pressure liquid refrigerant and a low-temperature, low-pressure gas refrigerant.
  • the refrigerant returning from the evaporator to the compressor 15 is further vaporized and becomes a gas refrigerant that does not contain liquid phase components. Therefore, the possibility of liquid compression occurring in the compressor 15 is reduced, and the compressor 15 can be operated more stably.
  • the refrigerant flowing through the first flow path 51 or the second flow path 52 is supercooled and becomes in an even lower temperature state. This makes it possible to suppress the generation of flash gas.
  • liquid refrigerant and gas refrigerant are provided in opposite directions in the liquid-gas heat exchanger 30.
  • the above-mentioned configurations are adopted.
  • the second four-way valve 40 is disposed in an area (on the low-pressure gas flow path 54) where only the low-pressure gaseous refrigerant flows.
  • the high-pressure refrigerant with a different temperature does not flow into the second four-way valve 40.
  • the second four-way valve 40 is disposed between the indoor heat exchanger 11 and the compressor 15. Therefore, for example, during cooling operation, only low-pressure refrigerant that has passed through the indoor heat exchanger 11 flows into the second four-way valve 40. This reduces the possibility of inadvertent heat exchange between low-temperature refrigerant and high-temperature refrigerant inside the second four-way valve 40. Therefore, the heat quantity of the refrigerant is stably maintained both before and after the second four-way valve 40, further improving the operating efficiency of the air conditioner 1.
  • the second four-way valve 40 is disposed between the first four-way valve 20 and the liquid-gas heat exchanger 30. Therefore, regardless of whether cooling operation or heating operation is being performed, only low-pressure refrigerant that has passed through the first four-way valve 20 flows into the second four-way valve 40. This reduces the possibility of inadvertent heat exchange between low-temperature refrigerant and high-temperature refrigerant inside the second four-way valve 40. As a result, the operating efficiency of the air conditioner 1 can be further improved.
  • a second embodiment of the present disclosure will be described with reference to Figs. 3 and 4.
  • the same reference numerals are used for the same configurations as those in the first embodiment, and detailed description will be omitted.
  • the position at which the accumulator 16 is provided is different from that in the first embodiment.
  • the accumulator 16 is provided between the first four-way valve 20 and the liquid-gas heat exchanger 30 on the low-pressure gas flow path 54.
  • the second four-way valve 40 and the liquid-gas heat exchanger 30 are disposed between the accumulator 16 and the compressor 15.
  • the liquid-gas heat exchanger 30 is provided downstream of the accumulator 16.
  • the compressor 15 is provided downstream of the liquid-gas heat exchanger 30.
  • the second four-way valve 40 is provided between the accumulator 16 and the liquid-gas compressor 15.
  • the low-pressure side refrigerant and the high-pressure side refrigerant in the liquid-gas heat exchanger 30 can be made to flow in countercurrent directions. This can further improve the heat exchange efficiency in the liquid-gas heat exchanger 30.
  • Figure 3 shows the refrigerant flow and the opening state of each valve during cooling operation
  • Figure 4 shows the refrigerant flow and the opening state of each valve during heating operation.
  • the refrigerant flow and the opening state of the valves are the same as in the first embodiment during either operation. Furthermore, the above-mentioned effects can be obtained in the same way during either operation.
  • the air conditioner 1 includes a refrigeration cycle 10 having an outdoor heat exchanger 13, an indoor heat exchanger 11, a compressor 15, and an expansion valve through which a refrigerant flows in sequence, a first four-way valve 20 that enables heating operation and cooling operation by switching the flow direction of the refrigerant, a liquid-gas heat exchanger 30 that exchanges heat between a gas refrigerant on the low pressure side of the refrigeration cycle 10 and a liquid refrigerant on the high pressure side, and a second four-way valve 40 that switches the flow of the refrigerant so that the gas refrigerant and the liquid refrigerant flow in countercurrent fashion in the liquid-gas heat exchanger 30 in both the heating operation and the cooling operation, and the second four-way valve 40 is disposed in an area through which the gaseous refrigerant on the low pressure side of the refrigeration cycle 10 flows.
  • the second four-way valve 40 is disposed in an area where low-pressure gaseous refrigerant flows. In other words, high-pressure refrigerant does not flow into the second four-way valve 40. This reduces the possibility of inadvertent heat exchange between low-temperature refrigerant and high-temperature refrigerant inside the second four-way valve 40. This further improves the operating efficiency of the air conditioner 1.
  • the air conditioner 1 according to the second aspect is the air conditioner 1 according to (1), in which the second four-way valve 40 is disposed between the indoor heat exchanger 11, which functions as an evaporator during the cooling operation, and the compressor 15.
  • the second four-way valve 40 is disposed between the indoor heat exchanger 11 and the compressor 15. Therefore, for example, during cooling operation, only low-pressure refrigerant that has passed through the indoor heat exchanger 11 flows into the second four-way valve 40. This reduces the possibility of inadvertent heat exchange between low-temperature refrigerant and high-temperature refrigerant inside the second four-way valve 40. This further improves the operating efficiency of the air conditioner 1.
  • the air conditioner 1 according to the third aspect is the air conditioner 1 according to (1) or (2), in which the second four-way valve 40 is disposed between the first four-way valve 20 and the liquid-gas heat exchanger 30.
  • the second four-way valve 40 is disposed between the first four-way valve 20 and the liquid-gas heat exchanger 30. Therefore, regardless of whether cooling operation or heating operation is being performed, only low-pressure refrigerant that has passed through the first four-way valve 20 flows into the second four-way valve 40. This reduces the possibility of inadvertent heat exchange between low-temperature refrigerant and high-temperature refrigerant inside the second four-way valve 40. This further improves the operating efficiency of the air conditioner 1.
  • the air conditioner 1 according to the fourth aspect is the air conditioner 1 according to any one of the aspects (1) to (3), in which the refrigeration cycle 10 is provided upstream of the compressor 15 and further includes an accumulator 16 that separates the refrigerant into gas and liquid, and the liquid-gas heat exchanger 30 and the second four-way valve 40 are disposed between the accumulator 16 and the compressor 15.
  • the liquid-gas heat exchanger 30 is disposed downstream of the accumulator 16, the refrigerant flowing into the accumulator 16 is not superheated. This makes it possible to maintain low fluidity of the lubricating oil that is mixed with the refrigerant in the accumulator 16. This makes it possible to smoothly guide the lubricating oil to each part of the compressor 15.
  • the compressor 15 is disposed downstream of the liquid-gas heat exchanger 30, superheated refrigerant flows into the compressor 15. This causes the liquid phase components of the refrigerant to vaporize, reducing the possibility of liquid compression occurring in the compressor 15.
  • the air conditioner 1 includes a refrigeration cycle 10 having an outdoor heat exchanger 13, an indoor heat exchanger 11, a compressor 15, and an expansion valve through which a refrigerant flows in sequence, a first four-way valve 20 that enables heating operation and cooling operation by switching the flow direction of the refrigerant, a liquid-gas heat exchanger 30 that exchanges heat between a gas refrigerant on the low pressure side of the refrigeration cycle 10 and a liquid refrigerant on the high pressure side, a second four-way valve 40 that switches the flow of the refrigerant so that the gas refrigerant and the liquid refrigerant flow in countercurrent flow in the liquid-gas heat exchanger 30 in both the heating operation and the cooling operation, and an accumulator 16 that is provided upstream of the compressor 15 and separates the refrigerant into gas and liquid, and the liquid-gas heat exchanger 30 is disposed between the accumulator 16 and the compressor 15.
  • the liquid-gas heat exchanger 30 is disposed downstream of the accumulator 16, the refrigerant flowing into the accumulator 16 is not superheated. This makes it possible to maintain low fluidity of the lubricating oil that is mixed with the refrigerant in the accumulator 16. This makes it possible to smoothly guide the lubricating oil to each part of the compressor 15.
  • the compressor 15 is disposed downstream of the liquid-gas heat exchanger 30, superheated refrigerant flows into the compressor 15. This causes the liquid phase components of the refrigerant to vaporize, reducing the possibility of liquid compression occurring in the compressor 15.
  • the air conditioner 1 according to the sixth aspect is the air conditioner 1 according to (5), in which the second four-way valve 40 is provided between the accumulator 16 and the liquid-gas heat exchanger 30.
  • the second four-way valve 40 is provided between the accumulator 16 and the liquid-gas compressor 15, the low-pressure side refrigerant and the high-pressure side refrigerant in the liquid-gas heat exchanger 30 can flow in countercurrent directions. This can further improve the heat exchange efficiency in the liquid-gas heat exchanger 30.
  • This disclosure makes it possible to provide an air conditioner with improved operating efficiency.

Abstract

This air conditioner comprises: a refrigeration cycle having an outdoor heat exchanger, an indoor heat exchanger, a compressor, and an expansion valve through each of which a refrigerant sequentially circulates; a first four-way valve that makes it possible to switch between a heating operation and a cooling operation by switching the circulation direction of the refrigerant; a liquid gas heat exchanger that exchanges heat between the refrigerant in a gas state on the low-pressure side of the refrigeration cycle and the refrigerant in a liquid state on the high-pressure side; and a second four-way valve that switches the flow of the refrigerant such that the gas refrigerant and the liquid refrigerant have opposite flows in the liquid gas heat exchanger in both the heating operation and the cooling operation, wherein the second four-way valve is disposed in a region in the refrigeration cycle where the refrigerant in the gas state on the low-pressure side circulates.

Description

空気調和機Air conditioners
　本開示は、空気調和機に関する。
　本願は、２０２２年９月２７日に日本に出願された特願２０２２－１５３６４９号について優先権を主張し、その内容をここに援用する。 The present disclosure relates to an air conditioner.
This application claims priority to Japanese Patent Application No. 2022-153649, filed in Japan on September 27, 2022, the contents of which are incorporated herein by reference.
　冷凍サイクルは、蒸発器、凝縮器、圧縮機、及び膨張弁を備え、例えば冷房運転時には、冷媒が圧縮機、凝縮器、膨張弁、蒸発器の順に順次流通する。ここで、蒸発器から圧縮機に戻る冷媒は、圧縮機における液圧縮を防ぐために可能な限り低温の気相であることが望ましい。また、冷媒配管内では、冷媒を過冷却することでフラッシュガスの発生を抑制したいという要請もある。 The refrigeration cycle includes an evaporator, a condenser, a compressor, and an expansion valve. For example, during cooling operation, the refrigerant flows through the compressor, condenser, expansion valve, and evaporator in that order. Here, it is desirable for the refrigerant returning from the evaporator to the compressor to be in the gas phase at as low a temperature as possible to prevent liquid compression in the compressor. There is also a demand to suppress the generation of flash gas within the refrigerant piping by supercooling the refrigerant.
　そこで、液ガス熱交換器を備えた空気調和機がこれまでに実用化されている。液ガス熱交換器を備えた空気調和機の具体例として下記特許文献１に記載されたものが知られている。下記特許文献１に係る空気調和機では、例えば冷房運転時には、蒸発器を通過した低温の気相冷媒と、凝縮器を通過した高温の液相冷媒とを液ガス熱交換器によって熱交換させる。これにより、上述の２つの要請を満たすことができるとされている。 As a result, air conditioners equipped with liquid-gas heat exchangers have been put to practical use. A specific example of an air conditioner equipped with a liquid-gas heat exchanger is known to be that described in Patent Document 1 below. In the air conditioner according to Patent Document 1 below, for example, during cooling operation, the liquid-gas heat exchanger exchanges heat between the low-temperature gas phase refrigerant that has passed through the evaporator and the high-temperature liquid phase refrigerant that has passed through the condenser. This is said to be able to meet the two requirements mentioned above.
　ところで、液ガス熱交換器内では、液相冷媒と気相冷媒とが、互いに対向する方向から流れる対向流状態であることが、熱効率を確保する観点から望ましい。そのため、下記特許文献１に係る装置では、冷房運転時と暖房運転時との間で、四方弁によって液ガス熱交換器に流入する冷媒の向きを適宜変更することが可能とされている。 In order to ensure thermal efficiency, it is desirable for the liquid-phase refrigerant and the gas-phase refrigerant to flow in opposite directions in a countercurrent state within the liquid-gas heat exchanger. Therefore, in the device described in Patent Document 1 below, the direction of the refrigerant flowing into the liquid-gas heat exchanger can be appropriately changed by a four-way valve between cooling operation and heating operation.
特開２００３－１９４４３２号公報JP 2003-194432 A
　しかしながら、上記特許文献１に係る空気調和機では、四方弁の内部を低温冷媒と高温冷媒の双方が流れてしまう。このため、当該四方弁の内部で冷媒同士の間における不用意な熱交換が生じて、運転効率が低下してしまう可能性がある。 However, in the air conditioner disclosed in Patent Document 1, both low-temperature and high-temperature refrigerants flow inside the four-way valve. This can lead to inadvertent heat exchange between the refrigerants inside the four-way valve, reducing operating efficiency.
　本開示は上記課題を解決するためになされたものであって、運転効率がさらに向上した空気調和機を提供することを目的とする。 This disclosure has been made to solve the above problems, and aims to provide an air conditioner with improved operating efficiency.
　上記課題を解決するために、本開示に係る空気調和機は、それぞれ冷媒が順次流通する室外熱交換器、室内熱交換器、圧縮機、及び膨張弁を有する冷凍サイクルと、前記冷媒の流通方向を切り替えることで、暖房運転、及び冷房運転を可能とする第一四方弁と、前記冷凍サイクルの低圧側のガス冷媒と高圧側の液冷媒とを熱交換させる液ガス熱交換器と、前記暖房運転及び前記冷房運転のいずれでも、前記液ガス熱交換器で前記ガス冷媒と前記液冷媒とが対向流となるように、前記冷媒の流れを切り替える第二四方弁と、を備え、前記第二四方弁は、前記冷凍サイクルにおける前記低圧側のガス状態の冷媒が流通する領域に配置されている。 In order to solve the above problems, the air conditioner according to the present disclosure comprises a refrigeration cycle having an outdoor heat exchanger, an indoor heat exchanger, a compressor, and an expansion valve through which a refrigerant flows in sequence, a first four-way valve that enables heating operation and cooling operation by switching the flow direction of the refrigerant, a liquid-gas heat exchanger that exchanges heat between a gas refrigerant on the low pressure side of the refrigeration cycle and a liquid refrigerant on the high pressure side, and a second four-way valve that switches the flow of the refrigerant so that the gas refrigerant and the liquid refrigerant flow in counter directions in the liquid-gas heat exchanger in both the heating operation and the cooling operation, and the second four-way valve is disposed in an area through which the gaseous refrigerant on the low pressure side of the refrigeration cycle flows.
　本開示に係る空気調和機は、それぞれ冷媒が順次流通する室外熱交換器、室内熱交換器、圧縮機、及び膨張弁を有する冷凍サイクルと、前記冷媒の流通方向を切り替えることで、暖房運転、及び冷房運転を可能とする第一四方弁と、前記冷凍サイクルの低圧側のガス冷媒と高圧側の液冷媒とを熱交換させる液ガス熱交換器と、前記暖房運転及び前記冷房運転のいずれでも、前記液ガス熱交換器で前記ガス冷媒と前記液冷媒とが対向流となるように、前記冷媒の流れを切り替える第二四方弁と、前記圧縮機の上流側に設けられ、前記冷媒を気液分離するアキュムレータと、を備え、前記液ガス熱交換器は、前記アキュムレータと前記圧縮機との間に配置されている。 The air conditioner according to the present disclosure comprises a refrigeration cycle having an outdoor heat exchanger, an indoor heat exchanger, a compressor, and an expansion valve through which a refrigerant flows in sequence; a first four-way valve that enables heating operation and cooling operation by switching the flow direction of the refrigerant; a liquid-gas heat exchanger that exchanges heat between a gas refrigerant on the low pressure side of the refrigeration cycle and a liquid refrigerant on the high pressure side; a second four-way valve that switches the flow of the refrigerant so that the gas refrigerant and the liquid refrigerant flow in countercurrent flow in the liquid-gas heat exchanger in both the heating operation and the cooling operation; and an accumulator that is provided upstream of the compressor and separates the refrigerant into gas and liquid, and the liquid-gas heat exchanger is disposed between the accumulator and the compressor.
　本開示によれば、運転効率がさらに向上した空気調和機を提供することができる。 This disclosure makes it possible to provide an air conditioner with improved operating efficiency.
本開示の第一実施形態に係る空気調和機の回路図であって、冷房運転時における冷媒の流れを示す図である。FIG. 2 is a circuit diagram of the air conditioner according to the first embodiment of the present disclosure, illustrating the flow of refrigerant during cooling operation. 本開示の第一実施形態に係る空気調和機の回路図であって、暖房運転時における冷媒の流れを示す図である。FIG. 2 is a circuit diagram of the air conditioner according to the first embodiment of the present disclosure, showing the flow of refrigerant during heating operation. 本開示の第二実施形態に係る空気調和機の回路図であって、冷房運転時における冷媒の流れを示す図である。FIG. 11 is a circuit diagram of an air conditioner according to a second embodiment of the present disclosure, illustrating the flow of refrigerant during cooling operation. 本開示の第二実施形態に係る空気調和機の回路図であって、暖房運転時における冷媒の流れを示す図である。FIG. 11 is a circuit diagram of an air conditioner according to a second embodiment of the present disclosure, illustrating the flow of refrigerant during heating operation. 本開示の第二実施形態に係る空気調和機の変形例を示す回路図である。FIG. 11 is a circuit diagram showing a modified example of the air conditioner according to the second embodiment of the present disclosure.
＜第一実施形態＞
（空気調和機の構成）
　以下、本開示の第一実施形態に係る空気調和機１について、図１と図２を参照して説明する。本実施形態に係る空気調和機１は、例えば家屋等の建築物や、自動車等の輸送機械に設置されて、室内の温度を指定された値に調節するための装置である。 First Embodiment
(Configuration of the air conditioner)
An air conditioner 1 according to a first embodiment of the present disclosure will be described below with reference to Figures 1 and 2. The air conditioner 1 according to this embodiment is a device that is installed in a building such as a house or in transportation machinery such as an automobile, and adjusts the indoor temperature to a specified value.
　図１に示すように、空気調和機１は、冷凍サイクル１０と、第一四方弁２０と、液ガス熱交換器３０と、第二四方弁４０と、を備えている。冷凍サイクル１０は、当該冷凍サイクル１０のそれぞれの機器を順次流通する冷媒を圧縮したり膨張させたりすることで、室内の空気と冷媒、及び室外の空気と冷媒との間で熱交換を行うための回路である。 As shown in FIG. 1, the air conditioner 1 includes a refrigeration cycle 10, a first four-way valve 20, a liquid-gas heat exchanger 30, and a second four-way valve 40. The refrigeration cycle 10 is a circuit for performing heat exchange between the indoor air and the refrigerant, and between the outdoor air and the refrigerant, by compressing and expanding the refrigerant that flows through each device of the refrigeration cycle 10 in sequence.
（冷凍サイクルの構成）
　冷凍サイクル１０は、室内熱交換器１１と、室内ファン１２と、室外熱交換器１３と、室外ファン１４と、圧縮機１５と、アキュムレータ１６と、第一膨張弁１７（膨張弁）と、第二膨張弁１８（膨張弁）と、第一流路５１と、第二流路５２と、圧縮機流路５３と、低圧ガス流路５４と、を有する。 (Configuration of refrigeration cycle)
The refrigeration cycle 10 has an indoor heat exchanger 11, an indoor fan 12, an outdoor heat exchanger 13, an outdoor fan 14, a compressor 15, an accumulator 16, a first expansion valve 17 (expansion valve), a second expansion valve 18 (expansion valve), a first flow path 51, a second flow path 52, a compressor flow path 53, and a low-pressure gas flow path 54.
　室内熱交換器１１は、第一流路５１上に配置されている。第一流路５１は、後述する第一四方弁２０と液ガス熱交換器３０との間を接続する流路である。第一流路５１の内部には冷媒が充填されている。室内熱交換器１１は、第一流路５１内を流通する冷媒と室内の空気との間で熱交換をさせる。室内熱交換器１１は、例えばフィンアンドチューブ方式の熱交換器である。室内熱交換器１１の近傍には室内ファン１２が設けられている。室内ファン１２を運転することで、室内の空気が室内熱交換器１１に強制的に供給される。 The indoor heat exchanger 11 is disposed on the first flow path 51. The first flow path 51 is a flow path that connects between the first four-way valve 20 and the liquid-gas heat exchanger 30, which will be described later. The inside of the first flow path 51 is filled with a refrigerant. The indoor heat exchanger 11 exchanges heat between the refrigerant flowing through the first flow path 51 and the indoor air. The indoor heat exchanger 11 is, for example, a fin-and-tube type heat exchanger. An indoor fan 12 is provided near the indoor heat exchanger 11. By operating the indoor fan 12, the indoor air is forcibly supplied to the indoor heat exchanger 11.
　第一流路５１上における室内熱交換器１１の液ガス熱交換器３０側の位置には、第一膨張弁１７が配置されている。第一膨張弁１７は例えば電磁膨張弁であり、外部から送信された電気信号によって開度が調整される。第一膨張弁１７は、冷房運転時に、第一流路５１内を流れる冷媒を膨張させてその圧力を下げるために用いられる。 A first expansion valve 17 is disposed on the first flow path 51 at a position on the liquid-gas heat exchanger 30 side of the indoor heat exchanger 11. The first expansion valve 17 is, for example, an electromagnetic expansion valve, and its opening is adjusted by an electrical signal sent from the outside. The first expansion valve 17 is used to expand the refrigerant flowing in the first flow path 51 during cooling operation, thereby reducing its pressure.
　室外熱交換器１３は、第二流路５２上に配置されている。第二流路５２は、第一四方弁２０と液ガス熱交換器３０との間を接続する流路であって、上記の第一流路５１とは別に設けられた流路である。第二流路５２の内部には冷媒が充填されている。室外熱交換器１３は、第二流路５２内を流通する冷媒と室外の空気との間で熱交換をさせる。室外熱交換器１３は、例えばフィンアンドチューブ方式の熱交換器である。室外熱交換器１３の近傍には室外ファン１４が設けられている。室外ファン１４を運転することで、室外の空気が室外熱交換器１３に強制的に供給される。 The outdoor heat exchanger 13 is disposed on the second flow path 52. The second flow path 52 is a flow path that connects the first four-way valve 20 and the liquid-gas heat exchanger 30, and is a flow path provided separately from the first flow path 51. The second flow path 52 is filled with a refrigerant. The outdoor heat exchanger 13 exchanges heat between the refrigerant flowing through the second flow path 52 and the outdoor air. The outdoor heat exchanger 13 is, for example, a fin-and-tube type heat exchanger. An outdoor fan 14 is provided near the outdoor heat exchanger 13. By operating the outdoor fan 14, outdoor air is forcibly supplied to the outdoor heat exchanger 13.
　第二流路５２上における室外熱交換器１３の液ガス熱交換器３０側の位置には、第二膨張弁１８が配置されている。第二膨張弁１８は例えば電磁膨張弁であり、外部から送信された電気信号によって開度が調整される。第二膨張弁１８は、暖房運転時に、第二流路５２内を流れる冷媒を膨張させてその圧力を下げるために用いられる。 A second expansion valve 18 is disposed on the second flow path 52 at a position on the liquid-gas heat exchanger 30 side of the outdoor heat exchanger 13. The second expansion valve 18 is, for example, an electromagnetic expansion valve, and its opening is adjusted by an electrical signal sent from the outside. The second expansion valve 18 is used to expand the refrigerant flowing in the second flow path 52 during heating operation, thereby reducing its pressure.
　圧縮機１５、及びアキュムレータ１６は、圧縮機流路５３上に設けられている。圧縮機流路５３は、液ガス熱交換器３０と第一四方弁２０とを接続する流路であって、上述の第一流路５１、及び第二流路５２とは異なる他の流路である。圧縮機１５は、圧縮機流路５３中のガス冷媒を圧縮して高温高圧のガス冷媒を生成する。圧縮機１５として具体的には、スクロール圧縮機やロータリ圧縮機が好適に用いられる。アキュムレータ１６は、圧縮機流路５３上における圧縮機１５の上流側に隣接して配置されている。アキュムレータ１６は、冷媒を気液分離して、気相成分のみを圧縮機１５に送り、液相成分を貯留する。なお、アキュムレータ１６に貯留される液相成分中には、冷媒と混在する潤滑油も含まれている。 The compressor 15 and the accumulator 16 are provided on the compressor flow path 53. The compressor flow path 53 is a flow path that connects the liquid-gas heat exchanger 30 and the first four-way valve 20, and is a flow path different from the first flow path 51 and the second flow path 52 described above. The compressor 15 compresses the gas refrigerant in the compressor flow path 53 to generate a high-temperature, high-pressure gas refrigerant. Specifically, a scroll compressor or a rotary compressor is preferably used as the compressor 15. The accumulator 16 is disposed adjacent to the upstream side of the compressor 15 on the compressor flow path 53. The accumulator 16 separates the refrigerant into gas and liquid, sends only the gas phase component to the compressor 15, and stores the liquid phase component. The liquid phase component stored in the accumulator 16 also contains lubricating oil mixed with the refrigerant.
　低圧ガス流路５４は、第一四方弁２０と液ガス熱交換器３０との間を、上記の圧縮機流路５３と並行するようにして接続している。低圧ガス流路５４上には、後述する第二四方弁４０が配置されている。 The low-pressure gas flow path 54 connects the first four-way valve 20 and the liquid-gas heat exchanger 30 in parallel with the compressor flow path 53. The second four-way valve 40, which will be described later, is disposed on the low-pressure gas flow path 54.
（第一四方弁の構成）
　第一四方弁２０は、上記の第一流路５１、第二流路５２、圧縮機流路５３、及び低圧ガス流路５４の接続状態を切り替えることで、冷媒の流通方向を切り替える。第一四方弁２０の開通状態を切り替えることで、暖房運転、及び冷房運転の切り替えが可能とされている。図１中では、冷房運転時における第一四方弁２０の開通状態を示している。具体的には、圧縮機流路５３と第二流路５２とが接続され、第一流路５１と低圧ガス流路５４とが接続されている。暖房運転時の状態については、図２を参照して後述する。 (Configuration of the first four-way valve)
The first four-way valve 20 switches the flow direction of the refrigerant by switching the connection state of the first flow path 51, the second flow path 52, the compressor flow path 53, and the low-pressure gas flow path 54. By switching the open state of the first four-way valve 20, it is possible to switch between heating operation and cooling operation. Fig. 1 shows the open state of the first four-way valve 20 during cooling operation. Specifically, the compressor flow path 53 and the second flow path 52 are connected, and the first flow path 51 and the low-pressure gas flow path 54 are connected. The state during heating operation will be described later with reference to Fig. 2.
（液ガス熱交換器の構成）
　液ガス熱交換器３０は、第一流路５１の第一膨張弁１７側の端部と、第二流路５２の第二膨張弁１８側の端部とを接続する位置に設けられている。また、液ガス熱交換器３０は、低圧ガス流路５４と圧縮機流路５３とを接続している。これにより、図１に示す冷房運転時には、第二流路５２から第一流路５１に向かう高温高圧の液冷媒と、低圧ガス流路５４から圧縮機流路５３に向かう低温低圧のガス冷媒とが熱交換する。液ガス熱交換器３０中では、これら２つの冷媒が互いに対向する向きから流れるように、つまり対向流となるように、その流れ方向が定められている。 (Configuration of liquid-gas heat exchanger)
The liquid-gas heat exchanger 30 is provided at a position connecting an end of the first flow path 51 on the first expansion valve 17 side and an end of the second flow path 52 on the second expansion valve 18 side. The liquid-gas heat exchanger 30 also connects the low-pressure gas flow path 54 and the compressor flow path 53. As a result, during the cooling operation shown in Fig. 1, heat is exchanged between a high-temperature, high-pressure liquid refrigerant flowing from the second flow path 52 to the first flow path 51 and a low-temperature, low-pressure gas refrigerant flowing from the low-pressure gas flow path 54 to the compressor flow path 53. In the liquid-gas heat exchanger 30, the flow directions of these two refrigerants are determined so that they flow in opposite directions to each other, that is, so that they flow in countercurrents.
（第二四方弁の構成）
　第二四方弁４０は、上記の液ガス熱交換器３０における２つの冷媒の流れが、暖房運転時及び冷房運転時のいずれでも対向流となるように冷媒の流れを切り替える。具体的には、第二四方弁４０は、低圧ガス流路５４、及び圧縮機流路５３と、液ガス熱交換器３０との開通状態を切り替える。図１に示す冷房運転時には、低圧ガス流路５４を通過した冷媒が、液ガス熱交換器３０を経て圧縮機流路５３に向かう。この時に、当該冷媒の流れ方向が、第二流路５２から第一流路５１に向かう冷媒の流れ方向とは反対となるように第二四方弁４０の開通状態が切り替えられる。 (Configuration of the second four-way valve)
The second four-way valve 40 switches the flow of refrigerant so that the two refrigerant flows in the liquid-gas heat exchanger 30 are counterflows both during heating operation and cooling operation. Specifically, the second four-way valve 40 switches the open states of the low-pressure gas flow path 54 and the compressor flow path 53, and the liquid-gas heat exchanger 30. During cooling operation as shown in Fig. 1, the refrigerant that has passed through the low-pressure gas flow path 54 passes through the liquid-gas heat exchanger 30 and heads toward the compressor flow path 53. At this time, the open state of the second four-way valve 40 is switched so that the flow direction of the refrigerant is opposite to the flow direction of the refrigerant from the second flow path 52 toward the first flow path 51.
　第二四方弁４０は、常態的に低圧ガス冷媒が流通する領域（つまり、低圧ガス流路５４上）に設けられている。言い換えれば、第二四方弁４０は、室内熱交換器１１と圧縮機１５との間に設けられていることが望ましい。さらに望ましくは、第二四方弁４０は、第一四方弁２０と、液ガス熱交換器３０との間に設けられている。 The second four-way valve 40 is provided in an area where low-pressure gas refrigerant normally flows (i.e., on the low-pressure gas flow path 54). In other words, it is preferable that the second four-way valve 40 is provided between the indoor heat exchanger 11 and the compressor 15. More preferably, the second four-way valve 40 is provided between the first four-way valve 20 and the liquid-gas heat exchanger 30.
（作用効果）
　続いて、空気調和機１の動作の一例について、図１と図２を参照して説明する。図１は、冷房運転時における空気調和機１の回路状態を示している。同図に示すように、まず、圧縮機１５で圧縮されて高温高圧となったガス冷媒は、第一四方弁２０を経て、第二流路５２上の室外熱交換器１３に流れる。室外熱交換器１３で室外の空気と熱交換したガス冷媒は、高圧の液冷媒となる。その後、この冷媒は、第二流路５２上の第二膨張弁１８を通過する。なお、冷房運転時には第二膨張弁１８は全開状態とされており、当該第二膨張弁１８を通過しても冷媒の圧力に変化は生じない。 (Action and Effect)
Next, an example of the operation of the air conditioner 1 will be described with reference to Fig. 1 and Fig. 2. Fig. 1 shows the circuit state of the air conditioner 1 during cooling operation. As shown in Fig. 1, first, the gas refrigerant compressed by the compressor 15 to a high temperature and high pressure passes through the first four-way valve 20 and flows to the outdoor heat exchanger 13 on the second flow path 52. The gas refrigerant that has exchanged heat with outdoor air in the outdoor heat exchanger 13 becomes a high-pressure liquid refrigerant. This refrigerant then passes through the second expansion valve 18 on the second flow path 52. Note that the second expansion valve 18 is fully open during cooling operation, and the pressure of the refrigerant does not change even when it passes through the second expansion valve 18.
　次いで、第二流路５２を通過した冷媒は、液ガス熱交換器３０に流入する。液ガス熱交換器３０では、この第二流路５２を通過した高温高圧の液冷媒は、後述する低温低圧のガス冷媒と熱交換する。これにより、液ガス熱交換器３０を通過して第一流路５１に流れ込む冷媒は、その温度が下がって過冷却度が上がった状態となる。過冷却状態となった冷媒は、次に第一膨張弁１７を通過する。これにより、冷媒は膨張して低温低圧の液冷媒となる。その後、室内熱交換器１１に流入した冷媒は、室内の空気と熱交換することで、その温度が上がるとともに気化して、低圧のガス冷媒となる。 Then, the refrigerant that has passed through the second flow path 52 flows into the liquid-gas heat exchanger 30. In the liquid-gas heat exchanger 30, the high-temperature, high-pressure liquid refrigerant that has passed through the second flow path 52 exchanges heat with the low-temperature, low-pressure gas refrigerant described below. As a result, the refrigerant that passes through the liquid-gas heat exchanger 30 and flows into the first flow path 51 drops in temperature and becomes in a state of increased subcooling. The refrigerant in the subcooled state then passes through the first expansion valve 17. As a result, the refrigerant expands and becomes a low-temperature, low-pressure liquid refrigerant. The refrigerant that has flowed into the indoor heat exchanger 11 then exchanges heat with the indoor air, causing its temperature to rise and it to evaporate, becoming a low-pressure gas refrigerant.
　低圧のガス冷媒は、第一四方弁２０を通過して、低圧ガス流路５４に流入する。その後、この低圧のガス冷媒は、第二四方弁４０を通過して、液ガス熱交換器３０で上述の高温高圧の液冷媒と熱交換する。これにより、低圧ガス冷媒が過熱された状態となる。過熱された低圧ガス冷媒は、再び第二四方弁４０を通過した後、アキュムレータ１６、及び圧縮機１５に流れる。以上のサイクルが連続的に生じることで、空気調和機１が冷房運転される。 The low-pressure gas refrigerant passes through the first four-way valve 20 and flows into the low-pressure gas flow path 54. This low-pressure gas refrigerant then passes through the second four-way valve 40 and exchanges heat with the high-temperature, high-pressure liquid refrigerant described above in the liquid-gas heat exchanger 30. This causes the low-pressure gas refrigerant to become superheated. The superheated low-pressure gas refrigerant passes through the second four-way valve 40 again, and then flows into the accumulator 16 and compressor 15. The above cycle occurs continuously, causing the air conditioner 1 to operate in cooling mode.
　次に、図２を参照して、暖房運転時における空気調和機１の動作について説明する。同図に示すように、まず、圧縮機１５で圧縮されて高温高圧となったガス冷媒は、第一四方弁２０を経て、第一流路５１上の室内熱交換器１１に流れる。室内熱交換器１１で室内の空気と熱交換したガス冷媒は、高圧の液冷媒となる。その後、この冷媒は、第一流路５１上の第一膨張弁１７を通過する。なお、暖房運転時には第一膨張弁１７は全開状態とされており、当該第一膨張弁１７を通過しても冷媒の圧力に変化は生じない。 Next, referring to Figure 2, the operation of the air conditioner 1 during heating operation will be described. As shown in the figure, first, the gas refrigerant compressed by the compressor 15 to a high temperature and high pressure flows through the first four-way valve 20 to the indoor heat exchanger 11 on the first flow path 51. After exchanging heat with the indoor air in the indoor heat exchanger 11, the gas refrigerant becomes a high-pressure liquid refrigerant. This refrigerant then passes through the first expansion valve 17 on the first flow path 51. Note that the first expansion valve 17 is fully open during heating operation, and there is no change in the pressure of the refrigerant even when it passes through the first expansion valve 17.
　次いで、第一流路５１を通過した冷媒は、液ガス熱交換器３０に流入する。液ガス熱交換器３０では、この第一流路５１を通過した高温高圧の液冷媒は、後述する低温低圧のガス冷媒と熱交換する。これにより、液ガス熱交換器３０を通過して第二流路５２に流れ込む冷媒は、その温度が下がって過冷却度が上がった状態となる。過冷却状態となった冷媒は、次に第二膨張弁１８を通過する。これにより、冷媒は膨張して低温低圧の液冷媒となる。その後、室外熱交換器１３に流入した冷媒は、室外の空気と熱交換することで、その温度が上がるとともに気化して、低圧のガス冷媒となる。 The refrigerant that has passed through the first flow path 51 then flows into the liquid-gas heat exchanger 30. In the liquid-gas heat exchanger 30, the high-temperature, high-pressure liquid refrigerant that has passed through the first flow path 51 exchanges heat with a low-temperature, low-pressure gas refrigerant, which will be described later. As a result, the refrigerant that passes through the liquid-gas heat exchanger 30 and flows into the second flow path 52 has a lower temperature and a higher degree of subcooling. The subcooled refrigerant then passes through the second expansion valve 18. As a result, the refrigerant expands and becomes a low-temperature, low-pressure liquid refrigerant. The refrigerant that has flowed into the outdoor heat exchanger 13 then exchanges heat with the outdoor air, causing its temperature to rise and it to evaporate, becoming a low-pressure gas refrigerant.
　低圧のガス冷媒は、第一四方弁２０を通過して、低圧ガス流路５４に流入する。その後、この低圧のガス冷媒は、第二四方弁４０を通過して、液ガス熱交換器３０で上述の高温高圧の液冷媒と熱交換する。これにより、低圧ガス冷媒が過熱された状態となる。過熱された低圧ガス冷媒は、再び第二四方弁４０を通過した後、アキュムレータ１６、及び圧縮機１５に流れる。以上のサイクルが連続的に生じることで、空気調和機１が暖房運転される。 The low-pressure gas refrigerant passes through the first four-way valve 20 and flows into the low-pressure gas flow path 54. This low-pressure gas refrigerant then passes through the second four-way valve 40 and exchanges heat with the high-temperature, high-pressure liquid refrigerant described above in the liquid-gas heat exchanger 30. This causes the low-pressure gas refrigerant to become superheated. The superheated low-pressure gas refrigerant passes through the second four-way valve 40 again, and then flows into the accumulator 16 and compressor 15. The above cycle occurs continuously, causing the air conditioner 1 to operate in heating mode.
　ここで、蒸発器としての室内熱交換器１１、又は室外熱交換器１３から圧縮機１５に戻る冷媒は、圧縮機１５における液圧縮を防ぐために可能な限り低温のガス冷媒であることが望ましい。また、冷媒配管内では、冷媒を過冷却することでフラッシュガスの発生を抑制したいという要請もある。そこで、本実施形態に係る空気調和機１では、液ガス熱交換器３０によって、これら２つの要請に対応している。具体的には、液ガス熱交換器３０を用いることで、高温高圧の液冷媒と低温低圧のガス冷媒とを熱交換させることができる。これにより、蒸発器から圧縮機１５に戻る冷媒では、気化がさらに進んで、液相成分を含まないガス冷媒となる。したがって、圧縮機１５で液圧縮が生じる可能性が低減され、当該圧縮機１５をより安定的に運転することが可能となる。反対に、第一流路５１、又は第二流路５２を流れる冷媒は、過冷却されてさらに低温の状態となる。これにより、フラッシュガスの発生を抑制することができる。 Here, it is desirable that the refrigerant returning to the compressor 15 from the indoor heat exchanger 11 or the outdoor heat exchanger 13 as an evaporator is a gas refrigerant with the lowest possible temperature to prevent liquid compression in the compressor 15. In addition, there is also a demand to suppress the generation of flash gas by supercooling the refrigerant in the refrigerant piping. Therefore, in the air conditioner 1 according to this embodiment, these two demands are met by the liquid-gas heat exchanger 30. Specifically, by using the liquid-gas heat exchanger 30, heat exchange can be performed between a high-temperature, high-pressure liquid refrigerant and a low-temperature, low-pressure gas refrigerant. As a result, the refrigerant returning from the evaporator to the compressor 15 is further vaporized and becomes a gas refrigerant that does not contain liquid phase components. Therefore, the possibility of liquid compression occurring in the compressor 15 is reduced, and the compressor 15 can be operated more stably. On the other hand, the refrigerant flowing through the first flow path 51 or the second flow path 52 is supercooled and becomes in an even lower temperature state. This makes it possible to suppress the generation of flash gas.
　ここで、液ガス熱交換器３０内では、液冷媒とガス冷媒とが、互いに対向する方向から流れる対向流状態であることが、熱効率を確保する観点から望ましい。このような状態を冷房運転時と暖房運転時のいずれでも実現するために、上述の各構成を採っている。 In order to ensure thermal efficiency, it is desirable for the liquid refrigerant and gas refrigerant to flow in opposite directions in the liquid-gas heat exchanger 30. In order to achieve this state during both cooling and heating operation, the above-mentioned configurations are adopted.
　上記構成によれば、第二四方弁４０が低圧側のガス状態の冷媒のみが流通する領域（低圧ガス流路５４上）に配置されている。つまり、当該第二四方弁４０には、温度の異なる高圧側の冷媒が流入しない。したがって、第二四方弁４０の内部で、低温冷媒と高温冷媒とが不用意に熱交換してしまう可能性を低減することができる。これにより、冷媒の熱量が第二四方弁４０の前後を通じて安定的に維持されるため、空気調和機１の運転効率をさらに向上させることができる。 With the above configuration, the second four-way valve 40 is disposed in an area (on the low-pressure gas flow path 54) where only the low-pressure gaseous refrigerant flows. In other words, the high-pressure refrigerant with a different temperature does not flow into the second four-way valve 40. This reduces the possibility of inadvertent heat exchange between low-temperature refrigerant and high-temperature refrigerant inside the second four-way valve 40. This allows the heat quantity of the refrigerant to be stably maintained both before and after the second four-way valve 40, further improving the operating efficiency of the air conditioner 1.
　また、上記構成によれば、第二四方弁４０が室内熱交換器１１と圧縮機１５との間に配置されている。したがって、例えば冷房運転時では、第二四方弁４０には、室内熱交換器１１を通過した低圧の冷媒のみ流入する。これにより、第二四方弁４０の内部で、低温冷媒と高温冷媒とが不用意に熱交換してしまう可能性を低減することができる。したがって、冷媒の熱量が第二四方弁４０の前後を通じて安定的に維持されるため、空気調和機１の運転効率をさらに向上させることができる。 Furthermore, according to the above configuration, the second four-way valve 40 is disposed between the indoor heat exchanger 11 and the compressor 15. Therefore, for example, during cooling operation, only low-pressure refrigerant that has passed through the indoor heat exchanger 11 flows into the second four-way valve 40. This reduces the possibility of inadvertent heat exchange between low-temperature refrigerant and high-temperature refrigerant inside the second four-way valve 40. Therefore, the heat quantity of the refrigerant is stably maintained both before and after the second four-way valve 40, further improving the operating efficiency of the air conditioner 1.
　加えて、上記構成によれば、第二四方弁４０が第一四方弁２０と液ガス熱交換器３０との間に配置されている。したがって、冷房運転時と暖房運転時とを問わず、第二四方弁４０には、第一四方弁２０を通過した低圧の冷媒のみ流入する。これにより、第二四方弁４０の内部で、低温冷媒と高温冷媒とが不用意に熱交換してしまう可能性を低減することができる。その結果、空気調和機１の運転効率をさらに向上させることができる。 In addition, according to the above configuration, the second four-way valve 40 is disposed between the first four-way valve 20 and the liquid-gas heat exchanger 30. Therefore, regardless of whether cooling operation or heating operation is being performed, only low-pressure refrigerant that has passed through the first four-way valve 20 flows into the second four-way valve 40. This reduces the possibility of inadvertent heat exchange between low-temperature refrigerant and high-temperature refrigerant inside the second four-way valve 40. As a result, the operating efficiency of the air conditioner 1 can be further improved.
　以上、本開示の第一実施形態について説明した。なお、本開示の要旨を逸脱しない限りにおいて、上記の構成に種々の変更や改修を施すことが可能である。 The above describes the first embodiment of the present disclosure. Note that various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure.
＜第二実施形態＞
　次に、本開示の第二実施形態について、図３と図４を参照して説明する。なお、上記の第一実施形態と同様の構成については同一の符号を付し、詳細な説明を省略する。図３に示すように、本実施形態では、アキュムレータ１６の設けられる位置が第一実施形態とは異なっている。具体的には、アキュムレータ１６は、低圧ガス流路５４上の第一四方弁２０と液ガス熱交換器３０との間に設けられている。言い換えると、第二四方弁４０、及び液ガス熱交換器３０は、アキュムレータ１６と圧縮機１５との間に配置されている。さらに言い換えれば、液ガス熱交換器３０はアキュムレータ１６よりも下流側に設けられている。また、圧縮機１５は液ガス熱交換器３０の下流側に設けられている。 Second Embodiment
Next, a second embodiment of the present disclosure will be described with reference to Figs. 3 and 4. The same reference numerals are used for the same configurations as those in the first embodiment, and detailed description will be omitted. As shown in Fig. 3, in this embodiment, the position at which the accumulator 16 is provided is different from that in the first embodiment. Specifically, the accumulator 16 is provided between the first four-way valve 20 and the liquid-gas heat exchanger 30 on the low-pressure gas flow path 54. In other words, the second four-way valve 40 and the liquid-gas heat exchanger 30 are disposed between the accumulator 16 and the compressor 15. In other words, the liquid-gas heat exchanger 30 is provided downstream of the accumulator 16. In addition, the compressor 15 is provided downstream of the liquid-gas heat exchanger 30.
（作用効果）
　上記構成によれば、液ガス熱交換器３０がアキュムレータ１６よりも下流側に配置されていることから、アキュムレータ１６に流入する冷媒は、液ガス熱交換器３０における熱交換を経ておらず、過熱されていない状態である。これにより、アキュムレータ１６内で冷媒とともに混在する潤滑油の流動性を低く保つことができる。したがって、圧縮機１５の各部に潤滑油を円滑に導くことが可能となる。 (Action and Effect)
According to the above configuration, since the liquid-gas heat exchanger 30 is disposed downstream of the accumulator 16, the refrigerant flowing into the accumulator 16 does not undergo heat exchange in the liquid-gas heat exchanger 30 and is not superheated. This makes it possible to keep the fluidity of the lubricating oil that is mixed with the refrigerant in the accumulator 16 low. This makes it possible to smoothly guide the lubricating oil to each part of the compressor 15.
　特に、近年導入が進められているプロパンを主成分とするＲ２９０等の冷媒では、温度が上がるに従って潤滑油の流動性が低くなる傾向にあることが知られている。このため、当該冷媒を過熱すると、流動性の低くなった潤滑油がアキュムレータ１６内に滞留してしまう可能性がある。しかしながら、上記構成によれば、アキュムレータ１６に流入する冷媒には過熱が施されていないことから、このような可能性を大きく低減することが可能となる。その結果、空気調和機１をより安定的に運転することができる。 In particular, it is known that with refrigerants such as R290, which is primarily composed of propane and has been increasingly introduced in recent years, the fluidity of the lubricating oil tends to decrease as the temperature increases. For this reason, if the refrigerant is overheated, the lubricating oil with reduced fluidity may accumulate in the accumulator 16. However, with the above configuration, the refrigerant flowing into the accumulator 16 is not superheated, which greatly reduces the possibility of this happening. As a result, the air conditioner 1 can be operated more stably.
　加えて、上記構成によれば、圧縮機１５は液ガス熱交換器３０の下流側に配置されていることから、当該圧縮機１５には過熱された冷媒が流入する。これにより、冷媒の液相成分がさらに気化するため、圧縮機１５で液圧縮が生じる可能性をより一層低減することができる。 In addition, with the above configuration, since the compressor 15 is disposed downstream of the liquid-gas heat exchanger 30, superheated refrigerant flows into the compressor 15. This causes the liquid phase components of the refrigerant to further vaporize, further reducing the possibility of liquid compression occurring in the compressor 15.
　また、上記構成によれば、第二四方弁４０がアキュムレータ１６と液ガス圧縮機１５との間に設けられている。これにより、第一実施形態で説明したように、液ガス熱交換器３０における低圧側冷媒と高圧側冷媒が互いに対向流となるようにこれら冷媒を流すことができる。これにより、液ガス熱交換器３０における熱交換効率をさらに向上させることができる。 Furthermore, according to the above configuration, the second four-way valve 40 is provided between the accumulator 16 and the liquid-gas compressor 15. As a result, as described in the first embodiment, the low-pressure side refrigerant and the high-pressure side refrigerant in the liquid-gas heat exchanger 30 can be made to flow in countercurrent directions. This can further improve the heat exchange efficiency in the liquid-gas heat exchanger 30.
　なお、図３は、冷房運転時における冷媒の流れと各弁の開通状態を示し、図４は暖房運転時における冷媒の流れと各弁の開通状態を示している。これら図に示すように、いずれの運転時においても、冷媒の流れや弁の開通状態は、第一実施形態と同様である。また、いずれの運転時においても、上記した効果を同様に得ることができる。 Note that Figure 3 shows the refrigerant flow and the opening state of each valve during cooling operation, and Figure 4 shows the refrigerant flow and the opening state of each valve during heating operation. As shown in these figures, the refrigerant flow and the opening state of the valves are the same as in the first embodiment during either operation. Furthermore, the above-mentioned effects can be obtained in the same way during either operation.
　以上、本開示の第二実施形態について説明した。なお、本開示の要旨を逸脱しない限りにおいて、上記の構成に種々の変更や改修を施すことが可能である。例えば、上記第二実施形態では、アキュムレータ１６と圧縮機１５との間に、第二四方弁４０、及び液ガス熱交換器３０が配置されている例について説明した。しかしながら、変形例として図５に示すように、アキュムレータ１６と圧縮機１５との間に液ガス熱交換器３０のみを配置し、第二四方弁４０は、アキュムレータ１６の上流側に配置されていてもよい。 The above describes the second embodiment of the present disclosure. Note that various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure. For example, in the above second embodiment, an example has been described in which the second four-way valve 40 and the liquid-gas heat exchanger 30 are disposed between the accumulator 16 and the compressor 15. However, as a modified example, as shown in FIG. 5, only the liquid-gas heat exchanger 30 may be disposed between the accumulator 16 and the compressor 15, and the second four-way valve 40 may be disposed upstream of the accumulator 16.
＜付記＞
　各実施形態に記載の空気調和機１は、例えば以下のように把握される。 <Additional Notes>
The air conditioner 1 described in each embodiment can be understood, for example, as follows.
（１）第１の態様に係る空気調和機１は、それぞれ冷媒が順次流通する室外熱交換器１３、室内熱交換器１１、圧縮機１５、及び膨張弁を有する冷凍サイクル１０と、前記冷媒の流通方向を切り替えることで、暖房運転、及び冷房運転を可能とする第一四方弁２０と、前記冷凍サイクル１０の低圧側のガス冷媒と高圧側の液冷媒とを熱交換させる液ガス熱交換器３０と、前記暖房運転及び前記冷房運転のいずれでも、前記液ガス熱交換器３０で前記ガス冷媒と前記液冷媒とが対向流となるように、前記冷媒の流れを切り替える第二四方弁４０と、を備え、前記第二四方弁４０は、前記冷凍サイクル１０における前記低圧側のガス状態の冷媒が流通する領域に配置されている。 (1) The air conditioner 1 according to the first aspect includes a refrigeration cycle 10 having an outdoor heat exchanger 13, an indoor heat exchanger 11, a compressor 15, and an expansion valve through which a refrigerant flows in sequence, a first four-way valve 20 that enables heating operation and cooling operation by switching the flow direction of the refrigerant, a liquid-gas heat exchanger 30 that exchanges heat between a gas refrigerant on the low pressure side of the refrigeration cycle 10 and a liquid refrigerant on the high pressure side, and a second four-way valve 40 that switches the flow of the refrigerant so that the gas refrigerant and the liquid refrigerant flow in countercurrent fashion in the liquid-gas heat exchanger 30 in both the heating operation and the cooling operation, and the second four-way valve 40 is disposed in an area through which the gaseous refrigerant on the low pressure side of the refrigeration cycle 10 flows.
　上記構成によれば、第二四方弁４０が低圧側のガス状態の冷媒が流通する領域に配置されている。つまり、当該第二四方弁４０には高圧側の冷媒が流入しない。したがって、第二四方弁４０の内部で、低温冷媒と高温冷媒とが不用意に熱交換してしまう可能性を低減することができる。これにより、空気調和機１の運転効率をさらに向上させることができる。 With the above configuration, the second four-way valve 40 is disposed in an area where low-pressure gaseous refrigerant flows. In other words, high-pressure refrigerant does not flow into the second four-way valve 40. This reduces the possibility of inadvertent heat exchange between low-temperature refrigerant and high-temperature refrigerant inside the second four-way valve 40. This further improves the operating efficiency of the air conditioner 1.
（２）第２の態様に係る空気調和機１は、（１）の空気調和機１であって、前記第二四方弁４０は、前記冷房運転時において蒸発器として機能する前記室内熱交換器１１と前記圧縮機１５との間に配置されている。 (2) The air conditioner 1 according to the second aspect is the air conditioner 1 according to (1), in which the second four-way valve 40 is disposed between the indoor heat exchanger 11, which functions as an evaporator during the cooling operation, and the compressor 15.
　上記構成によれば、第二四方弁４０が室内熱交換器１１と圧縮機１５との間に配置されている。したがって、例えば冷房運転時では、第二四方弁４０には、室内熱交換器１１を通過した低圧の冷媒のみ流入する。これにより、第二四方弁４０の内部で、低温冷媒と高温冷媒とが不用意に熱交換してしまう可能性を低減することができる。これにより、空気調和機１の運転効率をさらに向上させることができる。 According to the above configuration, the second four-way valve 40 is disposed between the indoor heat exchanger 11 and the compressor 15. Therefore, for example, during cooling operation, only low-pressure refrigerant that has passed through the indoor heat exchanger 11 flows into the second four-way valve 40. This reduces the possibility of inadvertent heat exchange between low-temperature refrigerant and high-temperature refrigerant inside the second four-way valve 40. This further improves the operating efficiency of the air conditioner 1.
（３）第３の態様に係る空気調和機１は、（１）又は（２）の空気調和機１であって、前記第二四方弁４０は、前記第一四方弁２０と前記液ガス熱交換器３０との間に配置されている。 (3) The air conditioner 1 according to the third aspect is the air conditioner 1 according to (1) or (2), in which the second four-way valve 40 is disposed between the first four-way valve 20 and the liquid-gas heat exchanger 30.
　上記構成によれば、第二四方弁４０が第一四方弁２０と液ガス熱交換器３０との間に配置されている。したがって、冷房運転時と暖房運転時とを問わず、第二四方弁４０には、第一四方弁２０を通過した低圧の冷媒のみ流入する。これにより、第二四方弁４０の内部で、低温冷媒と高温冷媒とが不用意に熱交換してしまう可能性を低減することができる。これにより、空気調和機１の運転効率をさらに向上させることができる。 According to the above configuration, the second four-way valve 40 is disposed between the first four-way valve 20 and the liquid-gas heat exchanger 30. Therefore, regardless of whether cooling operation or heating operation is being performed, only low-pressure refrigerant that has passed through the first four-way valve 20 flows into the second four-way valve 40. This reduces the possibility of inadvertent heat exchange between low-temperature refrigerant and high-temperature refrigerant inside the second four-way valve 40. This further improves the operating efficiency of the air conditioner 1.
（４）第４の態様に係る空気調和機１は、（１）から（３）のいずれか一態様に係る空気調和機１であって、前記冷凍サイクル１０は、前記圧縮機１５の上流側に設けられ、前記冷媒を気液分離するアキュムレータ１６をさらに有し、前記液ガス熱交換器３０、及び前記第二四方弁４０は、前記アキュムレータ１６と前記圧縮機１５との間に配置されている。 (4) The air conditioner 1 according to the fourth aspect is the air conditioner 1 according to any one of the aspects (1) to (3), in which the refrigeration cycle 10 is provided upstream of the compressor 15 and further includes an accumulator 16 that separates the refrigerant into gas and liquid, and the liquid-gas heat exchanger 30 and the second four-way valve 40 are disposed between the accumulator 16 and the compressor 15.
　上記構成によれば、液ガス熱交換器３０がアキュムレータ１６よりも下流側に配置されていることから、アキュムレータ１６に流入する冷媒は過熱されていない状態である。これにより、アキュムレータ１６内で冷媒とともに混在する潤滑油の流動性を低く保つことができる。したがって、圧縮機１５の各部に潤滑油を円滑に導くことが可能となる。加えて、圧縮機１５は液ガス熱交換器３０の下流側に配置されていることから、当該圧縮機１５には過熱された冷媒が流入する。これにより、冷媒の液相成分が気化するため、圧縮機１５で液圧縮が生じる可能性を低減することができる。 With the above configuration, since the liquid-gas heat exchanger 30 is disposed downstream of the accumulator 16, the refrigerant flowing into the accumulator 16 is not superheated. This makes it possible to maintain low fluidity of the lubricating oil that is mixed with the refrigerant in the accumulator 16. This makes it possible to smoothly guide the lubricating oil to each part of the compressor 15. In addition, since the compressor 15 is disposed downstream of the liquid-gas heat exchanger 30, superheated refrigerant flows into the compressor 15. This causes the liquid phase components of the refrigerant to vaporize, reducing the possibility of liquid compression occurring in the compressor 15.
（５）第５の態様に係る空気調和機１は、それぞれ冷媒が順次流通する室外熱交換器１３、室内熱交換器１１、圧縮機１５、及び膨張弁を有する冷凍サイクル１０と、前記冷媒の流通方向を切り替えることで、暖房運転、及び冷房運転を可能とする第一四方弁２０と、前記冷凍サイクル１０の低圧側のガス冷媒と高圧側の液冷媒とを熱交換させる液ガス熱交換器３０と、前記暖房運転及び前記冷房運転のいずれでも、前記液ガス熱交換器３０で前記ガス冷媒と前記液冷媒とが対向流となるように、前記冷媒の流れを切り替える第二四方弁４０と、前記圧縮機１５の上流側に設けられ、前記冷媒を気液分離するアキュムレータ１６と、を備え、前記液ガス熱交換器３０は、前記アキュムレータ１６と前記圧縮機１５との間に配置されている。 (5) The air conditioner 1 according to the fifth aspect includes a refrigeration cycle 10 having an outdoor heat exchanger 13, an indoor heat exchanger 11, a compressor 15, and an expansion valve through which a refrigerant flows in sequence, a first four-way valve 20 that enables heating operation and cooling operation by switching the flow direction of the refrigerant, a liquid-gas heat exchanger 30 that exchanges heat between a gas refrigerant on the low pressure side of the refrigeration cycle 10 and a liquid refrigerant on the high pressure side, a second four-way valve 40 that switches the flow of the refrigerant so that the gas refrigerant and the liquid refrigerant flow in countercurrent flow in the liquid-gas heat exchanger 30 in both the heating operation and the cooling operation, and an accumulator 16 that is provided upstream of the compressor 15 and separates the refrigerant into gas and liquid, and the liquid-gas heat exchanger 30 is disposed between the accumulator 16 and the compressor 15.
　上記構成によれば、液ガス熱交換器３０がアキュムレータ１６よりも下流側に配置されていることから、アキュムレータ１６に流入する冷媒は過熱されていない状態である。これにより、アキュムレータ１６内で冷媒とともに混在する潤滑油の流動性を低く保つことができる。したがって、圧縮機１５の各部に潤滑油を円滑に導くことが可能となる。加えて、圧縮機１５は液ガス熱交換器３０の下流側に配置されていることから、当該圧縮機１５には過熱された冷媒が流入する。これにより、冷媒の液相成分が気化するため、圧縮機１５で液圧縮が生じる可能性を低減することができる。 With the above configuration, since the liquid-gas heat exchanger 30 is disposed downstream of the accumulator 16, the refrigerant flowing into the accumulator 16 is not superheated. This makes it possible to maintain low fluidity of the lubricating oil that is mixed with the refrigerant in the accumulator 16. This makes it possible to smoothly guide the lubricating oil to each part of the compressor 15. In addition, since the compressor 15 is disposed downstream of the liquid-gas heat exchanger 30, superheated refrigerant flows into the compressor 15. This causes the liquid phase components of the refrigerant to vaporize, reducing the possibility of liquid compression occurring in the compressor 15.
（６）第６の態様に係る空気調和機１は、（５）の空気調和機１であって、前記第二四方弁４０は、前記アキュムレータ１６と前記液ガス熱交換器３０との間に設けられている。 (6) The air conditioner 1 according to the sixth aspect is the air conditioner 1 according to (5), in which the second four-way valve 40 is provided between the accumulator 16 and the liquid-gas heat exchanger 30.
　上記構成によれば、第二四方弁４０がアキュムレータ１６と液ガス圧縮機１５との間に設けられていることから、液ガス熱交換器３０における低圧側冷媒と高圧側冷媒が互いに対向流となるようにこれら冷媒を流すことができる。これにより、液ガス熱交換器３０における熱交換効率をさらに向上させることができる。 With the above configuration, since the second four-way valve 40 is provided between the accumulator 16 and the liquid-gas compressor 15, the low-pressure side refrigerant and the high-pressure side refrigerant in the liquid-gas heat exchanger 30 can flow in countercurrent directions. This can further improve the heat exchange efficiency in the liquid-gas heat exchanger 30.
　本開示によれば、運転効率がさらに向上した空気調和機を提供することができる。 This disclosure makes it possible to provide an air conditioner with improved operating efficiency.
１…空気調和機
１０…冷凍サイクル
１１…室内熱交換器
１２…室内ファン
１３…室外熱交換器
１４…室外ファン
１５…圧縮機
１６…アキュムレータ
１７…第一膨張弁
１８…第二膨張弁
２０…第一四方弁
３０…液ガス熱交換器
４０…第二四方弁
５１…第一流路
５２…第二流路
５３…圧縮機流路
５４…低圧ガス流路 DESCRIPTION OF SYMBOLS 1...Air conditioner 10...Refrigeration cycle 11...Indoor heat exchanger 12...Indoor fan 13...Outdoor heat exchanger 14...Outdoor fan 15...Compressor 16...Accumulator 17...First expansion valve 18...Second expansion valve 20...First four-way valve 30...Liquid-to-gas heat exchanger 40...Second four-way valve 51...First flow path 52...Second flow path 53...Compressor flow path 54...Low-pressure gas flow path

Claims (6)

  1. 　それぞれ冷媒が順次流通する室外熱交換器、室内熱交換器、圧縮機、及び膨張弁を有する冷凍サイクルと、
    　前記冷媒の流通方向を切り替えることで、暖房運転、及び冷房運転を可能とする第一四方弁と、
    　前記冷凍サイクルの低圧側のガス冷媒と高圧側の液冷媒とを熱交換させる液ガス熱交換器と、
    　前記暖房運転及び前記冷房運転のいずれでも、前記液ガス熱交換器で前記ガス冷媒と前記液冷媒とが対向流となるように、前記冷媒の流れを切り替える第二四方弁と、
    を備え、
    　前記第二四方弁は、前記冷凍サイクルにおける前記低圧側のガス状態の冷媒が流通する領域に配置されている空気調和機。     a refrigeration cycle including an outdoor heat exchanger, an indoor heat exchanger, a compressor, and an expansion valve through which a refrigerant flows in sequence;
    A first four-way valve that enables heating operation and cooling operation by switching the flow direction of the refrigerant;
    a liquid-gas heat exchanger for exchanging heat between a gas refrigerant on a low pressure side of the refrigeration cycle and a liquid refrigerant on a high pressure side of the refrigeration cycle;
    a second four-way valve that switches the flow of the refrigerant so that the gas refrigerant and the liquid refrigerant flow in counter directions in the liquid-gas heat exchanger in both the heating operation and the cooling operation;
    Equipped with
    The second four-way valve is disposed in a region of the refrigeration cycle through which gaseous refrigerant flows on the low pressure side of the refrigeration cycle.
  2. 　前記第二四方弁は、前記冷房運転時において蒸発器として機能する前記室内熱交換器と前記圧縮機との間に配置されている請求項１に記載の空気調和機。 The air conditioner according to claim 1, wherein the second four-way valve is disposed between the indoor heat exchanger, which functions as an evaporator during the cooling operation, and the compressor.
  3. 　前記第二四方弁は、前記第一四方弁と前記液ガス熱交換器との間に配置されている請求項１又は２に記載の空気調和機。 The air conditioner according to claim 1 or 2, wherein the second four-way valve is disposed between the first four-way valve and the liquid-to-gas heat exchanger.
  4. 　前記冷凍サイクルは、
    　前記圧縮機の上流側に設けられ、前記冷媒を気液分離するアキュムレータをさらに有し、
    　前記液ガス熱交換器、及び前記第二四方弁は、前記アキュムレータと前記圧縮機との間に配置されている請求項１に記載の空気調和機。     The refrigeration cycle includes:
    The compressor further includes an accumulator that separates the refrigerant into gas and liquid.
    The air conditioner according to claim 1 , wherein the liquid-gas heat exchanger and the second four-way valve are disposed between the accumulator and the compressor.
  5. 　それぞれ冷媒が順次流通する室外熱交換器、室内熱交換器、圧縮機、及び膨張弁を有する冷凍サイクルと、
    　前記冷媒の流通方向を切り替えることで、暖房運転、及び冷房運転を可能とする第一四方弁と、
    　前記冷凍サイクルの低圧側のガス冷媒と高圧側の液冷媒とを熱交換させる液ガス熱交換器と、
    　前記暖房運転及び前記冷房運転のいずれでも、前記液ガス熱交換器で前記ガス冷媒と前記液冷媒とが対向流となるように、前記冷媒の流れを切り替える第二四方弁と、
    　前記圧縮機の上流側に設けられ、前記冷媒を気液分離するアキュムレータと、
    を備え、
    　前記液ガス熱交換器は、前記アキュムレータと前記圧縮機との間に配置されている空気調和機。     a refrigeration cycle including an outdoor heat exchanger, an indoor heat exchanger, a compressor, and an expansion valve through which a refrigerant flows in sequence;
    A first four-way valve that enables heating operation and cooling operation by switching the flow direction of the refrigerant;
    a liquid-gas heat exchanger for exchanging heat between a gas refrigerant on a low pressure side of the refrigeration cycle and a liquid refrigerant on a high pressure side of the refrigeration cycle;
    a second four-way valve that switches the flow of the refrigerant so that the gas refrigerant and the liquid refrigerant flow in counter directions in the liquid-gas heat exchanger in both the heating operation and the cooling operation;
    an accumulator provided upstream of the compressor for separating the refrigerant into gas and liquid;
    Equipped with
    The air conditioner, wherein the liquid-gas heat exchanger is disposed between the accumulator and the compressor.
  6. 　前記第二四方弁は、前記アキュムレータと前記液ガス熱交換器との間に設けられている請求項５に記載の空気調和機。 The air conditioner according to claim 5, wherein the second four-way valve is provided between the accumulator and the liquid-gas heat exchanger.
PCT/JP2023/034206 2022-09-27 2023-09-21 Air conditioner WO2024070872A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002130856A (en) * 2000-10-23 2002-05-09 Matsushita Seiko Co Ltd Refrigerating cycle device and control method thereof
JP2003194432A (en) * 2001-10-19 2003-07-09 Matsushita Electric Ind Co Ltd Refrigerating cycle device
US20120036854A1 (en) * 2009-04-29 2012-02-16 Carrier Corporation Transcritical thermally activated cooling, heating and refrigerating system
CN204553165U (en) * 2015-03-09 2015-08-12 Tcl空调器(中山)有限公司 Compressor and air conditioner
WO2021095134A1 (en) * 2019-11-12 2021-05-20 三菱電機株式会社 Outdoor unit and air conditioner device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002130856A (en) * 2000-10-23 2002-05-09 Matsushita Seiko Co Ltd Refrigerating cycle device and control method thereof
JP2003194432A (en) * 2001-10-19 2003-07-09 Matsushita Electric Ind Co Ltd Refrigerating cycle device
US20120036854A1 (en) * 2009-04-29 2012-02-16 Carrier Corporation Transcritical thermally activated cooling, heating and refrigerating system
CN204553165U (en) * 2015-03-09 2015-08-12 Tcl空调器(中山)有限公司 Compressor and air conditioner
WO2021095134A1 (en) * 2019-11-12 2021-05-20 三菱電機株式会社 Outdoor unit and air conditioner device

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