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WO2024142327A1 - Air conditioning device - Google Patents

Air conditioning device Download PDF

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Publication number
WO2024142327A1
WO2024142327A1 PCT/JP2022/048399 JP2022048399W WO2024142327A1 WO 2024142327 A1 WO2024142327 A1 WO 2024142327A1 JP 2022048399 W JP2022048399 W JP 2022048399W WO 2024142327 A1 WO2024142327 A1 WO 2024142327A1
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WO
WIPO (PCT)
Prior art keywords
refrigerant
heat exchanger
compressor
expansion valve
air conditioning
Prior art date
Application number
PCT/JP2022/048399
Other languages
French (fr)
Japanese (ja)
Inventor
孔明 仲島
聖也 稲田
Original Assignee
三菱電機株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to PCT/JP2022/048399 priority Critical patent/WO2024142327A1/en
Publication of WO2024142327A1 publication Critical patent/WO2024142327A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B1/00—Compression machines, plants or systems with non-reversible cycle

Definitions

  • the air conditioning apparatus of the present disclosure comprises a compressor, a first heat exchanger, a first expansion valve, a second heat exchanger, a first pipe, a second pipe, a second expansion valve, a junction, a third heat exchanger, and a fourth heat exchanger.
  • the compressor compresses the refrigerant.
  • the first heat exchanger exchanges heat between the air in the first space and the refrigerant.
  • the first expansion valve expands the refrigerant.
  • the second heat exchanger exchanges heat between the air in the second space and the refrigerant.
  • the first pipe connects the compressor, the first heat exchanger, the first expansion valve, and the second heat exchanger.
  • FIG. 1 is a diagram showing an example of the configuration of an air conditioning device 100.
  • the configuration of the air conditioning device 100 according to this embodiment will be described with reference to FIG. 1.
  • the air conditioning device 100 is capable of performing cooling operation and heating operation.
  • the air conditioning device 100 performs cooling operation or heating operation based on the user's operation on a setting device (e.g., a remote control).
  • the solid arrows in FIG. 1 indicate the flow of refrigerant during cooling operation.
  • the dashed arrows in FIG. 1 indicate the flow of refrigerant during heating operation. Additionally, the dashed arrows in FIG. 1 indicate the flow of detection signals from various sensors.
  • the air conditioning device 100 includes an outdoor unit 101 and an indoor unit 102.
  • the outdoor unit 101 and the indoor unit 102 are connected by pipes 21 and 22.
  • a portion of the first pipe 81 constitutes the pipes 21 and 22.
  • the first heat exchanger 31 exchanges heat between the air in the first space and the refrigerant.
  • the "first space” is typically the “outdoor space” in which the outdoor unit 101 is installed.
  • the first heat exchanger 31 is configured to exchange heat between the refrigerant flowing inside the first heat exchanger 31 and the air flowing outside the first heat exchanger 31.
  • the first heat exchanger 31 is configured to function as a condenser that condenses the refrigerant during cooling operation, and as an evaporator that evaporates the refrigerant during heating operation.
  • the outdoor blower 6 is configured to blow outdoor air to the first heat exchanger 31.
  • the outdoor blower 6 is configured to supply air to the first heat exchanger 31.
  • the indoor blower 7 is configured to blow indoor air to the second heat exchanger 32.
  • the indoor blower 7 is configured to supply air to the second heat exchanger 32.
  • the ROM stores the programs executed by the CPU 86.
  • the RAM temporarily stores data generated by the execution of the programs in the CPU 86.
  • the RAM can function as a temporary data memory used as a work area.
  • the control device 8 stores a mode flag indicating the operation mode in the RAM.
  • the control device 8 stores a cooling operation flag (mode flag) indicating the cooling operation in the RAM.
  • the control device 8 stores a heating operation flag (mode flag) indicating the heating operation in the RAM.
  • the air conditioning device 100 further includes an indoor temperature sensor 61 and a frequency sensor 63.
  • the indoor temperature sensor 61 is installed in the room where the indoor unit 102 is installed.
  • the indoor temperature sensor 61 detects the indoor temperature described above.
  • the frequency sensor 63 is installed in the compressor 1.
  • the frequency sensor 63 detects the frequency of the compressor motor (the operating frequency of the compressor 1).
  • the detection values detected by the indoor temperature sensor 61 and the frequency sensor 63 are input to the control device 8.
  • the control device 8 can control whether the second expansion valve 42 is opened and the opening degree of the second expansion valve 42.
  • the second expansion valve 42 is opened, the refrigerant discharged from the compressor 1 is branched at the branching section 65 into a first refrigerant A1 and a second refrigerant A2.
  • the first refrigerant A1 flows into the second piping 82 (bypass route).
  • the second expansion valve 42 is intended to draw a portion of the refrigerant discharged from the compressor 1 into the second piping 82 as the first refrigerant A1.
  • the refrigerant discharged from the compressor 1 that is different from the first refrigerant A1 is the second refrigerant A2.
  • the second refrigerant A2 moves in the direction of the solid arrow during cooling operation. Also, the second refrigerant A2 moves in the direction of the dashed arrow, which is the same direction as the solid arrow, during heating operation. Also, the second refrigerant A2 from the branching section 65 passes through the second pipe 82 and merges with the first refrigerant A1 at the merging section 66. This merged refrigerant is also referred to as the "merged refrigerant.”
  • the third heat exchanger 33 exchanges heat between the merged refrigerant and the first refrigerant A1. Specifically, the third heat exchanger 33 supplies heat from the first refrigerant A1 to the merged refrigerant (see the arrow of the third heat exchanger 33).
  • the fourth heat exchanger 34 exchanges heat between the second refrigerant A2 and the first refrigerant A1 that has passed through the third heat exchanger 33. Specifically, the fourth heat exchanger 34 supplies heat from the second refrigerant A2 to the first refrigerant A1 that has passed through the second expansion valve 42 (see the arrow of the fourth heat exchanger 34).
  • the cooling capacity and heating capacity are changed by changing the frequency of the compressor 1. Specifically, if the air conditioning load for maintaining the indoor temperature at the set temperature is high, the control device 8 increases the operating frequency of the compressor 1. On the other hand, if the air conditioning load is small, the control device 8 reduces the operating frequency of the compressor 1.
  • the control device 8 When the air conditioning load is low, the control device 8 gradually reduces the operating frequency of the compressor 1, and the operating frequency may reach a minimum value.
  • the minimum value is a value that is set individually in the specifications of the air conditioning device 100.
  • cooling operation if the cooling capacity when the operating frequency of the compressor 1 is at the minimum value is greater than the air conditioning load, the air will be cooled excessively, and the indoor temperature will gradually decrease.
  • heating operation if the heating capacity when operating at the minimum value is greater than the air conditioning load, the air will be heated excessively, and the indoor temperature will gradually rise.
  • a configuration can be considered in which the compressor is stopped to prevent excessive operation of the air conditioner (hereinafter also referred to as the "configuration of the first comparative example").
  • the air conditioner configured as the first comparative example described above stops the compressor during cooling operation when the indoor temperature reaches the set temperature -M.
  • the compressor stops the indoor temperature increases, and when the indoor temperature reaches the set temperature + a predetermined value N, the compressor operation is resumed.
  • the air conditioner configured as in the first comparative example stops the compressor during heating operation when the indoor temperature reaches the set temperature + M.
  • the indoor temperature decreases, and when the indoor temperature reaches the set temperature - N, the compressor operation is resumed.
  • the control device 8 opens the second expansion valve 42 to allow the first refrigerant A1 to flow into the second pipe 82. This allows the air conditioning device 100 to perform low-capacity operation while suppressing intermittent operation, as described below.
  • Fig. 2 is a ph diagram when the second expansion valve 42 is closed (when the first refrigerant A1 does not flow into the second pipe 82).
  • the flow of refrigerant during cooling operation by the air conditioning apparatus 100 will be described with reference to Fig. 2.
  • the refrigerant corresponding to point C1 in Fig. 2 is compressed by the compressor 1 and changes to a high-pressure gas refrigerant corresponding to point C2. This high-pressure gas refrigerant passes through the four-way valve 2 and flows into the first heat exchanger 31.
  • the refrigerant is heat exchanged with the outdoor air and changes into liquid refrigerant corresponding to point C3.
  • the liquid refrigerant discharged from the first heat exchanger 31 is depressurized by the first expansion valve 41 and changes into two-phase gas-liquid refrigerant corresponding to point C4.
  • the gas-liquid two-phase refrigerant flows into the second heat exchanger 32.
  • the refrigerant exchanges heat with the indoor air and changes into a low-pressure gas refrigerant corresponding to point C1.
  • This low-pressure gas refrigerant then passes through the four-way valve 2 and is sucked into the compressor 1.
  • the difference value obtained by subtracting the specific enthalpy hin of the refrigerant at the inlet of the second heat exchanger 32 from the specific enthalpy hout of the refrigerant at the outlet of the second heat exchanger 32 (indoor heat exchanger) is also called the "enthalpy difference ⁇ h.”
  • the enthalpy difference ⁇ h1 during cooling operation is the difference value obtained by subtracting the specific enthalpy of the refrigerant corresponding to point C4 from the specific enthalpy of the refrigerant corresponding to point C1.
  • the enthalpy difference ⁇ h2 during heating operation is the difference value obtained by subtracting the specific enthalpy of the refrigerant corresponding to point C3 from the specific enthalpy of the refrigerant corresponding to point C2.
  • the second refrigerant A2 branched at the branching section 65 exchanges heat in the fourth heat exchanger 34 with the first refrigerant A1 that has passed through the third heat exchanger 33. Specifically, the second refrigerant A2 dissipates heat to the first refrigerant A1 in the fourth heat exchanger 34. Due to this heat dissipation, the specific enthalpy of the second refrigerant A2 decreases, and the second refrigerant A2 changes into the refrigerant corresponding to point B3.
  • the first refrigerant A1 corresponding to point B3 passes through the first heat exchanger 31, the first expansion valve 41, and the second heat exchanger 32, and the first refrigerant A1 corresponding to point B3 changes into the refrigerant corresponding to points B4, B5, and B6 (see the explanation of Figure 2 above).
  • the first refrigerant A1 branched at the branching section 65 dissipates heat to the refrigerant after merging.
  • the specific enthalpy of the first refrigerant A1 decreases due to this heat dissipation, and the first refrigerant A1 changes to the refrigerant corresponding to point B8 (low-pressure liquid refrigerant).
  • the first refrigerant A1 is then depressurized by the second expansion valve 42. Due to this depressurization, the first refrigerant A1 changes to the refrigerant corresponding to point B9.
  • the first refrigerant A1 corresponding to point B9 (the first refrigerant that has passed through the third heat exchanger 33 and the second expansion valve 42) is heat exchanged with the second refrigerant A2 in the fourth heat exchanger 34.
  • the fourth heat exchanger 34 supplies heat from the second refrigerant A2 to the first refrigerant A1. Due to this supply of heat, the first refrigerant A1 corresponding to point B9 changes into the refrigerant corresponding to point B10.
  • the first refrigerant A1 corresponding to point B10 flows into the junction 66.
  • the merged refrigerant exchanges heat with the first refrigerant A1.
  • the third heat exchanger 33 supplies heat from the first refrigerant A1 to the merged refrigerant. This supply changes the merged refrigerant into the refrigerant corresponding to point B1. The merged refrigerant corresponding to point B1 is then sucked back into the compressor 1.
  • the flow of the first refrigerant A1 during heating operation is the same as the flow of the first refrigerant A1 during cooling operation.
  • FIG. 4 is a diagram showing the enthalpy difference during cooling operation and heating operation when the second expansion valve 42 is open.
  • the enthalpy difference during cooling operation will be explained.
  • the specific enthalpy of the refrigerant (the refrigerant corresponding to point B6) at the outlet side of the second heat exchanger 32 when the second expansion valve 42 is open is smaller than the specific enthalpy of the refrigerant (the refrigerant corresponding to point C1 in FIG. 2) at the outlet side of the second heat exchanger 32 when the second expansion valve 42 is closed.
  • the enthalpy difference during heating operation will be described.
  • the heat of the second refrigerant A2 is dissipated to the first refrigerant A1. Therefore, during heating operation, the specific enthalpy of the refrigerant (the refrigerant corresponding to point B3) on the inlet side of the second heat exchanger 32 when the second expansion valve 42 is open is smaller than the specific enthalpy of the refrigerant (the refrigerant corresponding to point C2 in FIG. 2) on the inlet side of the second heat exchanger 32 when the second expansion valve 42 is closed.
  • the enthalpy difference ⁇ h4 when the second expansion valve 42 is open is a difference value obtained by subtracting the specific enthalpy of the refrigerant corresponding to point B4 from the specific enthalpy of the refrigerant corresponding to point B3, as shown in FIG. 4. Therefore, the air conditioning device 100 can reduce the enthalpy difference when the second expansion valve 42 is open during heating operation compared to when the second expansion valve 42 is closed.
  • the amount of heat exchanged by the second heat exchanger 32 is expressed by the following formula (1) from the circulation flow rate Gr of the refrigerant flowing through the indoor unit 102 and the above-mentioned enthalpy difference.
  • Amount of heat exchanged by the second heat exchanger 32 Gr ⁇ ⁇ h (1)
  • the refrigerant discharged from the compressor 1 is divided into the first refrigerant A1 and the second refrigerant A2 at the branching section 65. Then, only the second refrigerant A2 flows into the indoor unit 102, and the first refrigerant A1 does not flow into the indoor unit 102. Therefore, by opening the second expansion valve 42, the air conditioning apparatus 100 can reduce the circulation flow rate Gr of the refrigerant flowing through the indoor unit 102. Furthermore, as described in Figures 2 and 4, by opening the second expansion valve 42, the enthalpy difference ⁇ h can be reduced.
  • the air conditioning device 100 can reduce the amount of heat exchanged by the second heat exchanger 32 from equation (1), and as a result, can perform low-capacity operation.
  • [Functional block diagram of the control device] 5 is a functional block diagram of the control device 8.
  • the control device 8 has an acquisition unit 103, a processing unit 104, a control unit 106, and a storage unit 108.
  • a set temperature 110 and an opening degree table 112 are stored in the storage unit 108.
  • the set temperature 110 is a temperature set by a user.
  • the opening degree table 112 will be described later.
  • the storage unit 108 corresponds to the "memory" in the present disclosure.
  • the detected temperature (room temperature) detected by the room temperature sensor 61 and the operating frequency detected by the frequency sensor 63 are input to the control device 8.
  • the acquisition unit 103 acquires the detected temperature and the operating frequency.
  • the detected temperature and the operating frequency are output to the processing unit 104.
  • the processing unit 104 determines whether or not to open the second expansion valve 42, and if the second expansion valve 42 is opened, specifies the opening degree of the second expansion valve 42.
  • the control device 8 judges whether the operating frequency of the compressor 1 is at the minimum value. Then, if it is judged that the operating frequency of the compressor 1 is at the minimum value, the control device 8 judges whether the detected temperature is lower than the set temperature 110 by at least a first predetermined temperature ⁇ .
  • a case where the detected temperature is lower than the set temperature by at least a first predetermined temperature ⁇ means a case where the operating frequency of the compressor 1 is at the minimum value and the cooling load is small. Therefore, in this case, the control device 8 decides to open the second expansion valve 42 to perform low-capacity operation.
  • the greater the opening of the second expansion valve 42 the greater the amount of the first refrigerant A1, and as a result, the less the amount of the second refrigerant A2 (i.e., the above-mentioned circulation flow rate Gr).
  • the greater the opening of the second expansion valve 42 the more the operating capacity of the air conditioning device 100 can be reduced.
  • control device 8 controls the opening degree of the second expansion valve 42 so that the opening degree increases as the difference between the set temperature and the detected temperature increases.
  • FIG. 6 is an example of the opening degree table 112.
  • the opening degree table 112 is stipulated such that the larger the difference value ⁇ T, the larger the opening degree D.
  • the opening degree D1 is associated with the difference value ⁇ T1.
  • the opening degree D2 is associated with the difference value ⁇ T2.
  • the opening degree D3 is associated with the difference value ⁇ T3.
  • the processing unit 104 determines the opening degree of the second expansion valve 42 by referring to the opening degree table of FIG. 6.
  • the processing unit 104 may use a function for specifying the opening degree. When the difference value ⁇ T is substituted, this function outputs the opening degree D. Furthermore, in this function, the larger the substituted difference value ⁇ T, the larger the opening degree D that is output.
  • the control device 8 judges whether or not the operating frequency of the compressor 1 is at the minimum value. Then, if it is judged that the operating frequency of the compressor 1 is at the minimum value, the control device 8 judges whether or not the detected temperature is higher than the set temperature 110 by at least a second predetermined temperature ⁇ .
  • a case where the detected temperature is higher than the set temperature by at least a second predetermined temperature ⁇ means a case where the operating frequency of the compressor 1 is at the minimum value and the heating load is small. Therefore, in this case, the control device 8 decides to open the second expansion valve 42. Note that the first predetermined temperature ⁇ and the second predetermined temperature ⁇ may be the same or different.
  • the opening degree is determined using the difference value and the above-mentioned opening degree table or the above-mentioned function.
  • the air conditioning device 100 can divide the refrigerant into the first refrigerant A1 and the second refrigerant A2 by the second expansion valve 42, whether in cooling operation or heating operation. Therefore, the circulation flow rate Gr (see formula (1)) of the refrigerant flowing through the indoor unit 102 (second heat exchanger 32) can be reduced. Then, whether in cooling operation or heating operation, the third heat exchanger 33 exchanges heat between the first refrigerant A1 and the refrigerant after the merger, and the fourth heat exchanger 34 exchanges heat between the second refrigerant A2 and the first refrigerant A1 that has passed through the third heat exchanger 33. Therefore, whether in heating operation or cooling operation, the air conditioning device 100 can reduce the operating capacity while suppressing the execution of the above-mentioned intermittent operation.
  • the fourth heat exchanger 34 supplies heat from the second refrigerant A2 to the first refrigerant A1 via the third heat exchanger 33. Therefore, point B2 corresponding to point C2 (see FIG. 2) slides to point B3 (see FIG. 3 and FIG. 4). At the same time, point B1 corresponding to point C1 (see FIG. 2) slides to point B6 (see FIG. 3 and FIG. 4). In other words, whether in cooling operation or heating operation, the enthalpy difference can be reduced by the heat exchange of the fourth heat exchanger 34, and as a result, the operating capacity can be reduced.
  • the third heat exchanger 33 supplies heat from the first refrigerant A1 to the merged refrigerant. Therefore, due to the heat exchange in the third heat exchanger 33, point B6 slides to point B1, which corresponds to point C1.
  • the air conditioning device 100 can make the thermal state of the refrigerant sucked into the compressor 1 when the second expansion valve 42 is open the same as the thermal state when the second expansion valve 42 is closed.
  • control device 8 controls the second expansion valve 42 so that the opening degree increases as the difference between the set temperature and the detected temperature increases. Therefore, the air conditioning device 100 can perform low-capacity operation according to the thermal load of the indoor space.
  • Fig. 7 is a flowchart showing the processing of the control device 8.
  • the processing of Fig. 7 is executed at predetermined intervals (for example, one second) while the air conditioning device 100 is performing cooling operation or heating operation.
  • the control device 8 determines whether the operation mode is cooling operation or heating operation. This determination is executed, for example, based on the above-mentioned mode flag. If the operation mode is cooling operation, the processing proceeds to step S4, and if the operation mode is heating operation, the processing proceeds to step S6.
  • FIG. 8 is a flowchart showing the flow of the cooling operation process in step S4.
  • step S42 it is determined whether the operating frequency of compressor 1 is at the minimum value. If the operating frequency of compressor 1 is not at the minimum value (NO in step S42), the process proceeds to step S44.
  • step S44 the control device 8 closes the second expansion valve 42. Then, the process of step S4 ends.
  • step S42 if the operating frequency of compressor 1 is at the minimum value (YES in step S42), the process proceeds to step S46.
  • step S46 the control device 8 determines whether the indoor temperature (the detected temperature described above) is lower than the set temperature by at least a first predetermined temperature ⁇ . If the indoor temperature is lower than the set temperature by at least a first predetermined temperature ⁇ (YES in step S46), in step S48, the control device 8 determines the opening degree of the second expansion valve 42.
  • the opening degree is determined, for example, using the opening degree table in FIG. 6.
  • step S50 the control device 8 opens the second expansion valve 42 to the opening degree determined in step S48. Then, the processing of step S4 ends.
  • FIG. 9 is a flowchart showing the flow of the heating operation process in step S6.
  • step S62 it is determined whether the operating frequency of compressor 1 is at the minimum value. If the operating frequency of compressor 1 is not at the minimum value (NO in step S62), the process proceeds to step S64.
  • step S64 the control device 8 closes the second expansion valve 42. Then, the process of step S6 ends.
  • step S62 if the operating frequency of compressor 1 is at the minimum value (YES in step S62), the process proceeds to step S66.
  • step S66 the control device 8 determines whether the indoor temperature (the detected temperature described above) is higher than the set temperature by at least a second predetermined temperature ⁇ . If the indoor temperature is higher than the set temperature by at least a second predetermined temperature ⁇ (YES in step S66), in step S68, the control device 8 determines the opening degree of the second expansion valve 42.
  • the opening degree is determined, for example, using the opening degree table in FIG. 6.
  • step S70 the control device 8 opens the second expansion valve 42 to the opening degree determined in step S68. Then, the processing of step S6 ends.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Compression-Type Refrigeration Machines With Reversible Cycles (AREA)
  • Other Air-Conditioning Systems (AREA)

Abstract

An air conditioning device (100) comprises a second pipe (82), a second expansion valve (42), a merging portion (66), a third heat exchanger (33) and a fourth heat exchanger (34). The second pipe (82) connects a suction side and a discharge side of a compressor (1), without connecting the compressor (1), a first heat exchanger (31), a first expansion valve (41) and a second heat exchanger (32). The second expansion valve (42) draws a portion of a refrigerant discharged from the compressor (1) into the second pipe (82) as a first refrigerant. The merging portion (66) allows the first refrigerant and a second refrigerant to merge. The third heat exchanger (33) performs heat exchange between the first refrigerant and the refrigerant that has merged at the merging portion (66). The fourth heat exchanger (34) performs heat exchange between the second refrigerant and the first refrigerant that has passed through the third heat exchanger (33).

Description

空気調和装置Air Conditioning Equipment
　本開示は、空気調和装置に関する。 This disclosure relates to air conditioning devices.
　特許文献１においては、暖房運転および冷房運転を実行する空調機が開示される。この空調機の暖房運転時において、圧縮機の回転数が最低回転数に到達しておりかつ室内機の負荷が少ない場合がある。この場合には、特許文献１記載の空調機は、暖房運転の運転能力を低下させる。この特許文献１において、暖房運転の運転能力の低下の手法として、冷媒の一部をバイパス経路に流通させることにより、室内機に流通される冷媒の量を減少させることが開示されている。 Patent Document 1 discloses an air conditioner that performs heating and cooling operations. During heating operation of this air conditioner, the compressor speed may reach its minimum speed and the load on the indoor unit may be low. In this case, the air conditioner described in Patent Document 1 reduces the operating capacity of the heating operation. Patent Document 1 discloses a method of reducing the operating capacity of the heating operation by circulating part of the refrigerant through a bypass path, thereby reducing the amount of refrigerant circulating through the indoor unit.
特開２０１０－２３０２８８号公報JP 2010-230288 A
　上述の空調機において、暖房運転の運転能力を低下させることは開示されている。しかしながら、冷房運転中に能力運転を低下させることは開示されていない。 In the above-mentioned air conditioner, it is disclosed that the operating capacity of the heating operation can be reduced. However, there is no disclosure that the operating capacity can be reduced during cooling operation.
　本開示は、このような課題を解決するためになされたものであって、その目的は、暖房運転中および冷房運転中のいずれであっても、運転能力を低下させることが可能な空気調和装置を提供することである。 The present disclosure has been made to solve these problems, and its purpose is to provide an air conditioner that can reduce the operating capacity whether in heating or cooling operation.
　本開示の空気調和装置は、圧縮機と、第１熱交換器と、第１膨張弁と、第２熱交換器と、第１配管と、第２配管と、第２膨張弁と、合流部と、第３熱交換器と、第４熱交換器とを備える。圧縮機は、冷媒を圧縮する。第１熱交換器は、第１空間の空気と冷媒との熱交換を行う。第１膨張弁は、冷媒を膨張させる。第２熱交換器は、第２空間の空気と冷媒との熱交換を行う。第１配管は、圧縮機、第１熱交換器、第１膨張弁、および第２熱交換器を接続する。第２配管は、圧縮機、第１熱交換器、第１膨張弁、および第２熱交換器を接続せずに、圧縮機の吸入側と、圧縮機の吐出側とを接続する。第２膨張弁は、圧縮機から吐出された冷媒の一部を第１冷媒として、第２配管に引込む。合流部では、第１冷媒と、圧縮機から吐出された冷媒のうち第１冷媒とは異なる第２冷媒とが合流する。第３熱交換器は、第１冷媒と、合流部で合流された冷媒との熱交換を行う。第４熱交換器は、第２冷媒と、第３熱交換器を経由した第１冷媒との熱交換を行う。 The air conditioning apparatus of the present disclosure comprises a compressor, a first heat exchanger, a first expansion valve, a second heat exchanger, a first pipe, a second pipe, a second expansion valve, a junction, a third heat exchanger, and a fourth heat exchanger. The compressor compresses the refrigerant. The first heat exchanger exchanges heat between the air in the first space and the refrigerant. The first expansion valve expands the refrigerant. The second heat exchanger exchanges heat between the air in the second space and the refrigerant. The first pipe connects the compressor, the first heat exchanger, the first expansion valve, and the second heat exchanger. The second pipe connects the suction side of the compressor to the discharge side of the compressor without connecting the compressor, the first heat exchanger, the first expansion valve, and the second heat exchanger. The second expansion valve draws a portion of the refrigerant discharged from the compressor into the second pipe as the first refrigerant. At the junction, the first refrigerant and a second refrigerant, which is different from the first refrigerant among the refrigerants discharged from the compressor, join together. The third heat exchanger exchanges heat between the first refrigerant and the refrigerant joined at the junction. The fourth heat exchanger exchanges heat between the second refrigerant and the first refrigerant that has passed through the third heat exchanger.
　本開示によれば、暖房運転中および冷房運転中のいずれであっても、運転能力を低下させることができる。 According to the present disclosure, the operating capacity can be reduced whether the unit is in heating or cooling operation.
空気調和装置の構成例を示す図である。FIG. 1 is a diagram illustrating an example of the configuration of an air conditioning device. 第２膨張弁が閉塞している場合のｐ－ｈ線図である。This is a ph diagram when the second expansion valve is blocked. 第２膨張弁が開放している場合のｐ－ｈ線図である。This is a ph diagram when the second expansion valve is open. 第２膨張弁４２が開放している場合におけるエンタルピ差を示す図である。FIG. 11 is a diagram showing the enthalpy difference when the second expansion valve 42 is open. 制御装置８の機能ブロック図である。FIG. 2 is a functional block diagram of the control device 8. 開度テーブルの一例を示す図である。FIG. 11 is a diagram showing an example of an opening degree table. 制御装置の処理を示すフローチャートである。4 is a flowchart showing a process of the control device. 冷房運転処理の流れを示すフローチャートである。10 is a flowchart showing a flow of a cooling operation process. 暖房運転処理の流れを示すフローチャートである。4 is a flowchart showing a flow of a heating operation process.
　以下、本実施の形態について、図面を参照しながら詳細に説明する。なお、図中の同一または相当部分には同一符号を付してその説明は繰り返さない。 The present embodiment will now be described in detail with reference to the drawings. Note that the same or corresponding parts in the drawings will be given the same reference numerals and their description will not be repeated.
　図１は、空気調和装置１００の構成例を示す図である。図１を参照して、本実施の形態に係る空気調和装置１００の構成について説明する。空気調和装置１００は、冷房運転および暖房運転を実行可能である。空気調和装置１００は、ユーザによる設定装置（たとえば、リモコン）への操作などに基づいて、冷房運転または暖房運転を実行する。図１の実線矢印は、冷房運転時における冷媒の流れを示している。図１の破線矢印は、暖房運転時における冷媒の流れを示している。また、図１の一点鎖線矢印は、各種センサからの検出信号の流れを示している。 FIG. 1 is a diagram showing an example of the configuration of an air conditioning device 100. The configuration of the air conditioning device 100 according to this embodiment will be described with reference to FIG. 1. The air conditioning device 100 is capable of performing cooling operation and heating operation. The air conditioning device 100 performs cooling operation or heating operation based on the user's operation on a setting device (e.g., a remote control). The solid arrows in FIG. 1 indicate the flow of refrigerant during cooling operation. The dashed arrows in FIG. 1 indicate the flow of refrigerant during heating operation. Additionally, the dashed arrows in FIG. 1 indicate the flow of detection signals from various sensors.
　図１に示されるように、空気調和装置１００は、室外機１０１と、室内機１０２とを備えている。室外機１０１と室内機１０２とは、配管２１と配管２２とにより接続されている。第１配管８１の一部が配管２１および配管２２を構成している。 As shown in FIG. 1, the air conditioning device 100 includes an outdoor unit 101 and an indoor unit 102. The outdoor unit 101 and the indoor unit 102 are connected by pipes 21 and 22. A portion of the first pipe 81 constitutes the pipes 21 and 22.
　室外機１０１は、圧縮機１、四方弁２、第１熱交換器３１、第１膨張弁４１、室外送風機６、および制御装置８を含む。第１熱交換器３１は、「室外熱交換器」とも称される。室内機１０２は、第２熱交換器３２、および室内送風機７を含む。第２熱交換器３２は、「室内熱交換器」とも称される。 The outdoor unit 101 includes a compressor 1, a four-way valve 2, a first heat exchanger 31, a first expansion valve 41, an outdoor blower 6, and a control device 8. The first heat exchanger 31 is also referred to as the "outdoor heat exchanger." The indoor unit 102 includes a second heat exchanger 32 and an indoor blower 7. The second heat exchanger 32 is also referred to as the "indoor heat exchanger."
　冷媒回路１０は、圧縮機１、四方弁２、第１熱交換器３１、第１膨張弁４１、および第２熱交換器３２を含んでいる。圧縮機１、四方弁２、第１熱交換器３１、第１膨張弁４１および第２熱交換器３２は、第１配管８１によって接続されている。冷媒回路１０は、冷媒を循環させるように構成されている。 The refrigerant circuit 10 includes a compressor 1, a four-way valve 2, a first heat exchanger 31, a first expansion valve 41, and a second heat exchanger 32. The compressor 1, the four-way valve 2, the first heat exchanger 31, the first expansion valve 41, and the second heat exchanger 32 are connected by a first pipe 81. The refrigerant circuit 10 is configured to circulate the refrigerant.
　冷媒は室外機１０１と、室内機１０２との間の熱を輸送する冷凍サイクルに用いられる。冷媒は、たとえば、非共沸混合冷媒である。非共沸混合冷媒は、Ｒ３２を含み、他の冷媒としてＲ１２３４ｙｆを含んでいてもよい。非共沸混合冷媒は、他の冷媒としてＲ１１２３あるいはＲ１２３４ｚｅを含んでいてもよい。また、非共沸混合冷媒は、３種類以上の混合冷媒であってもよい。 The refrigerant is used in a refrigeration cycle that transports heat between the outdoor unit 101 and the indoor unit 102. The refrigerant is, for example, a non-azeotropic refrigerant mixture. The non-azeotropic refrigerant mixture includes R32, and may include R1234yf as another refrigerant. The non-azeotropic refrigerant mixture may include R1123 or R1234ze as another refrigerant. The non-azeotropic refrigerant mixture may also be a mixture of three or more types of refrigerants.
　冷媒回路１０は、冷房運転中には、圧縮機１、四方弁２、第１熱交換器３１、第１膨張弁４１、第２熱交換器３２、四方弁２の順に冷媒が循環するように構成されている。また、冷媒回路１０は、暖房運転中には、圧縮機１、四方弁２、第２熱交換器３２、第１膨張弁４１、第１熱交換器３１、四方弁２の順に冷媒が循環するように構成されている。 The refrigerant circuit 10 is configured such that during cooling operation, the refrigerant circulates in the order of the compressor 1, four-way valve 2, first heat exchanger 31, first expansion valve 41, second heat exchanger 32, and four-way valve 2. Also, during heating operation, the refrigerant circuit 10 is configured such that the refrigerant circulates in the order of the compressor 1, four-way valve 2, second heat exchanger 32, first expansion valve 41, first heat exchanger 31, and four-way valve 2.
　圧縮機１は、冷媒を圧縮するように構成されている。圧縮機１は、熱交換器（第１熱交換器３１または第２熱交換器３２）に流入する非共沸混合冷媒を圧縮する。圧縮機１は、吸入した冷媒を圧縮して吐出するように構成されている。圧縮機１は、容量可変に構成されていてもよい。 Compressor 1 is configured to compress the refrigerant. Compressor 1 compresses the non-azeotropic refrigerant that flows into the heat exchanger (first heat exchanger 31 or second heat exchanger 32). Compressor 1 is configured to compress the refrigerant that is sucked in and discharge it. Compressor 1 may be configured to have a variable capacity.
　四方弁２は、圧縮機１により圧縮された冷媒を第１熱交換器３１または第２熱交換器３２に流すように冷媒の流れを切替えるように構成されている。四方弁２は、第１ポートＰ１～第４ポートＰ４を有している。第１ポートＰ１は、圧縮機１の吐出側に接続されている。第２ポートＰ２は、圧縮機１の吸入側に接続されている。第３ポートＰ３は、第１熱交換器３１に接続されている。第４ポートＰ４は、第２熱交換器３２に接続されている。 The four-way valve 2 is configured to switch the flow of the refrigerant compressed by the compressor 1 to flow to the first heat exchanger 31 or the second heat exchanger 32. The four-way valve 2 has a first port P1 to a fourth port P4. The first port P1 is connected to the discharge side of the compressor 1. The second port P2 is connected to the suction side of the compressor 1. The third port P3 is connected to the first heat exchanger 31. The fourth port P4 is connected to the second heat exchanger 32.
　四方弁２は、冷房運転中には圧縮機１から吐出された冷媒を第１熱交換器３１に流すように構成されている。冷房運転中には、四方弁２において第１ポートＰ１に第３ポートＰ３が接続されているとともに第２ポートＰ２に第４ポートＰ４が接続されている。また、四方弁２は、暖房運転中には圧縮機１から吐出された冷媒を第２熱交換器３２に流すように構成されている。暖房運転中には、四方弁２において第１ポートＰ１に第４ポートＰ４が接続されているとともに第２ポートＰ２に第３ポートＰ３が接続されている。 The four-way valve 2 is configured to allow the refrigerant discharged from the compressor 1 to flow to the first heat exchanger 31 during cooling operation. During cooling operation, the third port P3 is connected to the first port P1 of the four-way valve 2, and the fourth port P4 is connected to the second port P2 of the four-way valve 2. Furthermore, the four-way valve 2 is configured to allow the refrigerant discharged from the compressor 1 to flow to the second heat exchanger 32 during heating operation. During heating operation, the fourth port P4 is connected to the first port P1 of the four-way valve 2, and the third port P3 is connected to the second port P2 of the four-way valve 2.
　第１熱交換器３１は、第１空間の空気と冷媒との熱交換を行う。「第１空間」は、典型的には、室外機１０１が設置されている「室外の空間」である。具体的には、第１熱交換器３１は、第１熱交換器３１の内部を流れる冷媒と第１熱交換器３１の外部を流れる空気との間で熱交換を行うように構成されている。第１熱交換器３１は、冷房運転中には冷媒を凝縮させる凝縮器として機能し、暖房運転中には冷媒を蒸発させる蒸発器として機能するように構成されている。 The first heat exchanger 31 exchanges heat between the air in the first space and the refrigerant. The "first space" is typically the "outdoor space" in which the outdoor unit 101 is installed. Specifically, the first heat exchanger 31 is configured to exchange heat between the refrigerant flowing inside the first heat exchanger 31 and the air flowing outside the first heat exchanger 31. The first heat exchanger 31 is configured to function as a condenser that condenses the refrigerant during cooling operation, and as an evaporator that evaporates the refrigerant during heating operation.
　第２熱交換器３２は、第２空間の空気と冷媒との熱交換を行う。「第２空間」は、典型的には、室内機１０２が設置されている「室内の空間」である。第２熱交換器３２は、第２熱交換器３２の内部を流れる冷媒と第２熱交換器３２の外部を流れる空気との間で熱交換を行うように構成されている。第２熱交換器３２は、冷房運転中には冷媒を蒸発させる蒸発器として機能し、暖房運転中には冷媒を凝縮させる凝縮器として機能するように構成されている。 The second heat exchanger 32 exchanges heat between the air in the second space and the refrigerant. The "second space" is typically the "indoor space" in which the indoor unit 102 is installed. The second heat exchanger 32 is configured to exchange heat between the refrigerant flowing inside the second heat exchanger 32 and the air flowing outside the second heat exchanger 32. The second heat exchanger 32 is configured to function as an evaporator that evaporates the refrigerant during cooling operation, and as a condenser that condenses the refrigerant during heating operation.
　第１膨張弁４１は、凝縮器で凝縮された冷媒を膨張させることにより減圧させるように構成されている。第１膨張弁４１は、冷房運転中には第１熱交換器３１により凝縮された冷媒を減圧させ、暖房運転中には第２熱交換器３２により凝縮された冷媒を減圧させるように構成されている。第１膨張弁４１は、たとえば、電磁膨張弁である。 The first expansion valve 41 is configured to reduce the pressure of the refrigerant condensed in the condenser by expanding it. The first expansion valve 41 is configured to reduce the pressure of the refrigerant condensed by the first heat exchanger 31 during cooling operation, and to reduce the pressure of the refrigerant condensed by the second heat exchanger 32 during heating operation. The first expansion valve 41 is, for example, an electromagnetic expansion valve.
　室外送風機６は、第１熱交換器３１に室外の空気を送風するように構成されている。つまり、室外送風機６は、第１熱交換器３１に対して空気を供給するように構成されている。 The outdoor blower 6 is configured to blow outdoor air to the first heat exchanger 31. In other words, the outdoor blower 6 is configured to supply air to the first heat exchanger 31.
　室内送風機７は、第２熱交換器３２に室内の空気を送風するように構成されている。つまり、室内送風機７は、第２熱交換器３２に対して空気を供給するように構成されている。 The indoor blower 7 is configured to blow indoor air to the second heat exchanger 32. In other words, the indoor blower 7 is configured to supply air to the second heat exchanger 32.
　制御装置８は、空気調和装置１００の各機器等を制御するように構成されている。制御装置８は、圧縮機１、四方弁２、第１膨張弁４１、室外送風機６、室内送風機７、および後述の第２膨張弁４２などに電気的に接続されており、これらの動作を制御するように構成されている。 The control device 8 is configured to control each device of the air conditioning device 100. The control device 8 is electrically connected to the compressor 1, the four-way valve 2, the first expansion valve 41, the outdoor blower 6, the indoor blower 7, and the second expansion valve 42 described below, and is configured to control the operation of these devices.
　また、制御装置８は、設定温度と、室内温度とに基づいて、圧縮機１などを制御する。設定温度は、たとえば、ユーザにより設定される。また、室内温度は、室内機１０２が設置されている空間（室内）の温度である。制御装置８は、たとえば、室内温度が設定温度に近づくように圧縮機１などを制御する。具体的には、制御装置８は、熱負荷（空調負荷）に応じて、圧縮機１のモータの運転パラメータを制御する。運転パラメータは、たとえば、モータの運転周波数またはモータの回転速度である。本実施の形態においては、運転パラメータは、モータの運転周波数であるとする。たとえば、制御装置８は、室内温度を設定温度とするために（室内温度を冷却または加熱するために）必要な熱負荷に応じて運転周波数を制御する。制御装置８は、熱負荷が小さいほど運転周波数を低下させる。 The control device 8 also controls the compressor 1 and other components based on the set temperature and the indoor temperature. The set temperature is set by, for example, a user. The indoor temperature is the temperature of the space (room) in which the indoor unit 102 is installed. The control device 8 controls the compressor 1 and other components, for example, so that the indoor temperature approaches the set temperature. Specifically, the control device 8 controls the operation parameters of the motor of the compressor 1 in accordance with the thermal load (air conditioning load). The operation parameters are, for example, the operation frequency of the motor or the rotation speed of the motor. In this embodiment, the operation parameters are the operation frequency of the motor. For example, the control device 8 controls the operation frequency in accordance with the thermal load required to set the indoor temperature to the set temperature (to cool or heat the indoor temperature). The smaller the thermal load, the lower the operation frequency is.
　また、運転周波数には、該運転周波数の最小値（最低周波数）が規定されている。制御装置８が、運転周波数を低下させて、該運転周波数が最小値に到達した場合において熱負荷が小さい場合には、後述の低能力運転を実行する。 Furthermore, a minimum value (minimum frequency) of the operating frequency is specified. When the control device 8 lowers the operating frequency and the operating frequency reaches the minimum value, if the thermal load is small, the control device 8 executes low-capacity operation, which will be described later.
　また、制御装置８は、主たる構成要素として、ＣＰＵ（Central　Processing　Unit）８６と、メモリ８８とを有する。ＣＰＵ８６は、様々な処理および演算を実行する。各構成要素はデータバスによって相互に接続されている。メモリ８８は、ＲＯＭ（Read　Only　Memory）、およびＲＡＭ（Random　Access　Memory）などを含む。ＣＰＵ８６は、「プロセッサ」または「制御回路」とも称される。 The control device 8 also has, as its main components, a CPU (Central Processing Unit) 86 and a memory 88. The CPU 86 executes various processes and calculations. Each component is connected to each other via a data bus. The memory 88 includes a ROM (Read Only Memory) and a RAM (Random Access Memory), etc. The CPU 86 is also called a "processor" or a "control circuit."
　ＲＯＭは、ＣＰＵ８６にて実行されるプログラムを格納する。ＲＡＭは、ＣＰＵ８６におけるプログラムの実行により生成されるデータなどを一時的に格納する。ＲＡＭは、作業領域として利用される一時的なデータメモリとして機能できる。制御装置８は、運転モードを示すモードフラグをＲＡＭに記憶する。制御装置８は、冷房運転を実行する場合には、該冷房運転を示す冷房運転フラグ（モードフラグ）をＲＡＭに格納する。また、制御装置８は、暖房運転を実行する場合には、該暖房運転を示す暖房運転フラグ（モードフラグ）をＲＡＭに格納する。 The ROM stores the programs executed by the CPU 86. The RAM temporarily stores data generated by the execution of the programs in the CPU 86. The RAM can function as a temporary data memory used as a work area. The control device 8 stores a mode flag indicating the operation mode in the RAM. When performing cooling operation, the control device 8 stores a cooling operation flag (mode flag) indicating the cooling operation in the RAM. When performing heating operation, the control device 8 stores a heating operation flag (mode flag) indicating the heating operation in the RAM.
　空気調和装置１００は、さらに、室内温度センサ６１と、周波数センサ６３とを備える。室内温度センサ６１は、室内機１０２が設置されている室内に設置されている。室内温度センサ６１は、上述の室内温度を検出する。周波数センサ６３は、圧縮機１に設置されている。周波数センサ６３は、圧縮機モータの周波数（圧縮機１の運転周波数）を検出する。室内温度センサ６１、および周波数センサ６３で検出された検出値は、制御装置８に入力される。 The air conditioning device 100 further includes an indoor temperature sensor 61 and a frequency sensor 63. The indoor temperature sensor 61 is installed in the room where the indoor unit 102 is installed. The indoor temperature sensor 61 detects the indoor temperature described above. The frequency sensor 63 is installed in the compressor 1. The frequency sensor 63 detects the frequency of the compressor motor (the operating frequency of the compressor 1). The detection values detected by the indoor temperature sensor 61 and the frequency sensor 63 are input to the control device 8.
　空気調和装置１００は、さらに、第２配管８２と、第３熱交換器３３と、第４熱交換器３４と、第２膨張弁４２とを備える。第２配管８２は、圧縮機１、第１熱交換器３１、第１膨張弁４１、および第２熱交換器３２を接続しない配管である。第２配管８２の一端は、圧縮機１の冷媒の吐出側に接続されている。該接続されている箇所は、分岐部６５とも称される。また、第２配管８２の他端は、圧縮機１の冷媒の吸入側に接続されている。該接続されている箇所は、合流部６６とも称される。第２配管８２は、「冷媒のバイパス経路」の役割を果たす。第２膨張弁４２は、たとえば、電磁膨張弁である。 The air conditioning device 100 further includes a second pipe 82, a third heat exchanger 33, a fourth heat exchanger 34, and a second expansion valve 42. The second pipe 82 is a pipe that does not connect the compressor 1, the first heat exchanger 31, the first expansion valve 41, and the second heat exchanger 32. One end of the second pipe 82 is connected to the refrigerant discharge side of the compressor 1. This connection point is also referred to as the branch section 65. The other end of the second pipe 82 is connected to the refrigerant suction side of the compressor 1. This connection point is also referred to as the junction section 66. The second pipe 82 serves as a "refrigerant bypass path." The second expansion valve 42 is, for example, an electromagnetic expansion valve.
　制御装置８は、第２膨張弁４２の開放の有無および第２膨張弁４２の開度を制御できる。第２膨張弁４２が開放されたときに、圧縮機１から吐出された冷媒は、分岐部６５で第１冷媒Ａ１と、第２冷媒Ａ２とに分岐される。第１冷媒Ａ１は、第２配管８２（バイパス経路）に流入する。このように、第２膨張弁４２は、圧縮機１から吐出された冷媒の一部を第１冷媒Ａ１として、第２配管８２に引き込むためのものである。また、圧縮機１から吐出された冷媒のうち、第１冷媒Ａ１とは異なる冷媒は第２冷媒Ａ２である。 The control device 8 can control whether the second expansion valve 42 is opened and the opening degree of the second expansion valve 42. When the second expansion valve 42 is opened, the refrigerant discharged from the compressor 1 is branched at the branching section 65 into a first refrigerant A1 and a second refrigerant A2. The first refrigerant A1 flows into the second piping 82 (bypass route). In this way, the second expansion valve 42 is intended to draw a portion of the refrigerant discharged from the compressor 1 into the second piping 82 as the first refrigerant A1. Furthermore, the refrigerant discharged from the compressor 1 that is different from the first refrigerant A1 is the second refrigerant A2.
　第２冷媒Ａ２は、冷房運転中においては実線矢印の向きに移動する。また、第２冷媒Ａ２は、暖房運転中においては、実線矢印と同一の向きの破線矢印の向きに移動する。また、分岐部６５からの第２冷媒Ａ２は、第２配管８２を経由して合流部６６で第１冷媒Ａ１と合流する。該合流された冷媒は、「合流後冷媒」とも称される。 The second refrigerant A2 moves in the direction of the solid arrow during cooling operation. Also, the second refrigerant A2 moves in the direction of the dashed arrow, which is the same direction as the solid arrow, during heating operation. Also, the second refrigerant A2 from the branching section 65 passes through the second pipe 82 and merges with the first refrigerant A1 at the merging section 66. This merged refrigerant is also referred to as the "merged refrigerant."
　第３熱交換器３３は、合流後冷媒と、第１冷媒Ａ１との熱交換を行う。具体的には、第３熱交換器３３により、第１冷媒Ａ１の熱は、合流後冷媒に供給される（第３熱交換器３３の矢印参照）。 The third heat exchanger 33 exchanges heat between the merged refrigerant and the first refrigerant A1. Specifically, the third heat exchanger 33 supplies heat from the first refrigerant A1 to the merged refrigerant (see the arrow of the third heat exchanger 33).
　第４熱交換器３４は、第２冷媒Ａ２と、第３熱交換器３３を経由した第１冷媒Ａ１との熱交換を行う。具体的には、第４熱交換器３４により、第２冷媒Ａ２の熱は、第２膨張弁４２を経由した第１冷媒Ａ１に供給される（第４熱交換器３４の矢印参照）。 The fourth heat exchanger 34 exchanges heat between the second refrigerant A2 and the first refrigerant A1 that has passed through the third heat exchanger 33. Specifically, the fourth heat exchanger 34 supplies heat from the second refrigerant A2 to the first refrigerant A1 that has passed through the second expansion valve 42 (see the arrow of the fourth heat exchanger 34).
　次に、空気調和装置１００による低能力運転を説明する。空気調和装置１００では、圧縮機１の周波数を変化させることにより、冷房能力および暖房能力を変化させる。具体的には、室内温度を設定温度に維持するための空調負荷が高ければ、制御装置８は、圧縮機１の運転周波数を増加させる。一方、制御装置８は、この空調負荷が小さければ圧縮機１の運転周波数を低下させる。 Next, low capacity operation by the air conditioner 100 will be explained. In the air conditioner 100, the cooling capacity and heating capacity are changed by changing the frequency of the compressor 1. Specifically, if the air conditioning load for maintaining the indoor temperature at the set temperature is high, the control device 8 increases the operating frequency of the compressor 1. On the other hand, if the air conditioning load is small, the control device 8 reduces the operating frequency of the compressor 1.
　空調負荷が低い場合、制御装置８は、圧縮機１の運転周波数を徐々に低下させ、該運転周波数が、最小値に到達する場合がある。最小値は、空気調和装置１００の仕様で個別に設定される値である。冷房運転において、圧縮機１の運転周波数が最小値である場合の冷房能力が空調負荷より大きければ、過剰に空気を冷却するため、室内温度が徐々に低下する。同様に暖房運転では、最小値で運転した場合の暖房能力が空調負荷より多ければ、過剰に空気を加熱するため、室内温度が徐々に上昇する。 When the air conditioning load is low, the control device 8 gradually reduces the operating frequency of the compressor 1, and the operating frequency may reach a minimum value. The minimum value is a value that is set individually in the specifications of the air conditioning device 100. In cooling operation, if the cooling capacity when the operating frequency of the compressor 1 is at the minimum value is greater than the air conditioning load, the air will be cooled excessively, and the indoor temperature will gradually decrease. Similarly, in heating operation, if the heating capacity when operating at the minimum value is greater than the air conditioning load, the air will be heated excessively, and the indoor temperature will gradually rise.
　たとえば、圧縮機の運転周波数が最小値であり、かつ設定温度と室内温度との差分が所定値Ｍとなった場合には、空気調和装置の過剰な運転を防止するため、圧縮機を停止させる構成（以下、「第１の比較例の構成」とも称される。）が考えられる。 For example, when the operating frequency of the compressor is at a minimum value and the difference between the set temperature and the room temperature reaches a predetermined value M, a configuration can be considered in which the compressor is stopped to prevent excessive operation of the air conditioner (hereinafter also referred to as the "configuration of the first comparative example").
　上記の第１の比較例の構成の空気調和装置は、冷房運転中では、設定温度－Ｍに室内温度が到達した場合に圧縮機を停止させる。圧縮機が停止すると、室内温度が増加し、設定温度＋所定値Ｎに室内温度が到達した場合に圧縮機の運転を再開する。 The air conditioner configured as the first comparative example described above stops the compressor during cooling operation when the indoor temperature reaches the set temperature -M. When the compressor stops, the indoor temperature increases, and when the indoor temperature reaches the set temperature + a predetermined value N, the compressor operation is resumed.
　また、上記の第１の比較例の構成の空気調和装置は、暖房運転中では、設定温度＋Ｍに室内温度が到達した場合に圧縮機を停止させる。圧縮機が停止すると、室内温度が減少し、設定温度－Ｎに室内温度が到達した場合に圧縮機の運転を再開する。 Furthermore, the air conditioner configured as in the first comparative example stops the compressor during heating operation when the indoor temperature reaches the set temperature + M. When the compressor stops, the indoor temperature decreases, and when the indoor temperature reaches the set temperature - N, the compressor operation is resumed.
　このように、第１の比較例の構成の空気調和装置においては、空調負荷が小さい場合には、圧縮機の運転および停止を繰り返す断続運転が実行されることになる。この断続運転では圧縮機の停止の度に冷凍サイクル内の冷媒が均圧してしまう。したがって、第１の比較例の構成の空気調和装置においては、冷房能力および暖房能力が再び安定するまで時間がかかり、運転ロスが発生し、消費電力量が増加する問題などが発生する。 In this way, in an air conditioning device with the configuration of the first comparative example, when the air conditioning load is small, intermittent operation is performed in which the compressor is repeatedly started and stopped. In this intermittent operation, the refrigerant in the refrigeration cycle is pressure-equalized every time the compressor is stopped. Therefore, in an air conditioning device with the configuration of the first comparative example, it takes time for the cooling capacity and heating capacity to stabilize again, resulting in operational losses and problems such as increased power consumption.
　そこで、本実施の形態において、圧縮機１の運転周波数が最小値であり、かつ空調負荷が低い場合には、制御装置８は第２膨張弁４２を開放することにより、第１冷媒Ａ１を第２配管８２に流入させる。これにより、後述するように、空気調和装置１００は、断続運転を抑制しつつ低能力運転を実行することができる。 In this embodiment, when the operating frequency of the compressor 1 is at a minimum value and the air conditioning load is low, the control device 8 opens the second expansion valve 42 to allow the first refrigerant A1 to flow into the second pipe 82. This allows the air conditioning device 100 to perform low-capacity operation while suppressing intermittent operation, as described below.
　［第２膨張弁が閉塞している場合のｐ－ｈ線図］
　図２は、第２膨張弁４２が閉塞している場合（第１冷媒Ａ１が第２配管８２に流れない場合）のｐ－ｈ線図である。図２を参照して、空気調和装置１００による冷房運転中の冷媒の流れを説明する。図２の点Ｃ１に対応する冷媒は、圧縮機１で圧縮されることにより、点Ｃ２に対応する高圧ガス冷媒に変化する。この高圧ガス冷媒は、四方弁２を経由し、第１熱交換器３１に流入する。 [P-H diagram when the second expansion valve is blocked]
Fig. 2 is a ph diagram when the second expansion valve 42 is closed (when the first refrigerant A1 does not flow into the second pipe 82). The flow of refrigerant during cooling operation by the air conditioning apparatus 100 will be described with reference to Fig. 2. The refrigerant corresponding to point C1 in Fig. 2 is compressed by the compressor 1 and changes to a high-pressure gas refrigerant corresponding to point C2. This high-pressure gas refrigerant passes through the four-way valve 2 and flows into the first heat exchanger 31.
　第１熱交換器３１で冷媒は、室外空気と熱交換されることにより、点Ｃ３に対応する液冷媒に変化する。点Ｃ３に対応する液冷媒は、第１熱交換器３１から排出された液冷媒は第１膨張弁４１で減圧されることにより、点Ｃ４に対応する気液２相の冷媒に変化する。 In the first heat exchanger 31, the refrigerant is heat exchanged with the outdoor air and changes into liquid refrigerant corresponding to point C3. The liquid refrigerant discharged from the first heat exchanger 31 is depressurized by the first expansion valve 41 and changes into two-phase gas-liquid refrigerant corresponding to point C4.
　気液２相の冷媒は第２熱交換器３２に流入する。第２熱交換器３２で冷媒は、室内空気と熱交換されることにより、点Ｃ１に対応する低圧ガス冷媒に変化する。そして、この低圧ガス冷媒は、四方弁２を経由して、圧縮機１に吸入される。 The gas-liquid two-phase refrigerant flows into the second heat exchanger 32. In the second heat exchanger 32, the refrigerant exchanges heat with the indoor air and changes into a low-pressure gas refrigerant corresponding to point C1. This low-pressure gas refrigerant then passes through the four-way valve 2 and is sucked into the compressor 1.
　また、第２熱交換器３２（室内熱交換器）の出口での冷媒の比エンタルピｈｏｕｔから、第２熱交換器３２の入口での冷媒の比エンタルピｈｉｎが差引かれた差分値は、「エンタルピ差Δｈ」とも称される。 The difference value obtained by subtracting the specific enthalpy hin of the refrigerant at the inlet of the second heat exchanger 32 from the specific enthalpy hout of the refrigerant at the outlet of the second heat exchanger 32 (indoor heat exchanger) is also called the "enthalpy difference Δh."
　図２に示されるように、冷房運転中のエンタルピ差Δｈ１は、点Ｃ１に対応する冷媒の比エンタルピから、点Ｃ４に対応する冷媒の比エンタルピが差引かれた差分値となる。また、暖房運転中のエンタルピ差Δｈ２は、点Ｃ２に対応する冷媒の比エンタルピから、点Ｃ３に対応する冷媒の比エンタルピが差引かれた差分値となる。 As shown in FIG. 2, the enthalpy difference Δh1 during cooling operation is the difference value obtained by subtracting the specific enthalpy of the refrigerant corresponding to point C4 from the specific enthalpy of the refrigerant corresponding to point C1. Also, the enthalpy difference Δh2 during heating operation is the difference value obtained by subtracting the specific enthalpy of the refrigerant corresponding to point C3 from the specific enthalpy of the refrigerant corresponding to point C2.
　［第２膨張弁が開放している場合のｐ－ｈ線図］
　図３は、第２膨張弁４２が開放している場合のｐ－ｈ線図である。図３を参照して、空気調和装置１００による冷房運転中の冷媒の流れを説明する。図３の点Ｂ１に対応する冷媒は、圧縮機１で圧縮されることにより、点Ｂ２に対応する高圧ガス冷媒に変化する。高圧ガス冷媒は、上述したように、分岐部６５において、第１冷媒Ａ１と、第２冷媒Ａ２とに分割される。また、点Ｂ２～点Ｂ１０においては、黒丸・破線は、第１冷媒Ａ１の流れを示し、白丸・実線は、第２冷媒Ａ２の流れを示す。 [P-H diagram when the second expansion valve is open]
Fig. 3 is a ph diagram when the second expansion valve 42 is open. The flow of refrigerant during cooling operation by the air-conditioning apparatus 100 will be described with reference to Fig. 3. The refrigerant corresponding to point B1 in Fig. 3 is compressed by the compressor 1 and changes to a high-pressure gas refrigerant corresponding to point B2. As described above, the high-pressure gas refrigerant is divided into the first refrigerant A1 and the second refrigerant A2 at the branching section 65. In addition, at points B2 to B10, the black circles and dashed lines indicate the flow of the first refrigerant A1, and the white circles and solid lines indicate the flow of the second refrigerant A2.
　まず、第２冷媒Ａ２の流れを説明する。分岐部６５で分岐された第２冷媒Ａ２は、第４熱交換器３４において、第３熱交換器３３を経由した第１冷媒Ａ１と熱交換を行う。具体的には、第２冷媒Ａ２は、第４熱交換器３４において、第１冷媒Ａ１に放熱する。第２冷媒Ａ２は、当該放熱により、第２冷媒Ａ２の比エンタルピは減少することから、点Ｂ３に対応する冷媒に変化する。 First, the flow of the second refrigerant A2 will be explained. The second refrigerant A2 branched at the branching section 65 exchanges heat in the fourth heat exchanger 34 with the first refrigerant A1 that has passed through the third heat exchanger 33. Specifically, the second refrigerant A2 dissipates heat to the first refrigerant A1 in the fourth heat exchanger 34. Due to this heat dissipation, the specific enthalpy of the second refrigerant A2 decreases, and the second refrigerant A2 changes into the refrigerant corresponding to point B3.
　その後、点Ｂ３に対応する第１冷媒Ａ１は、第１熱交換器３１、第１膨張弁４１、および第２熱交換器３２を経由することから、点Ｂ３に対応する第１冷媒Ａ１は、点Ｂ４，点Ｂ５、および点Ｂ６に対応する冷媒へと変化する（上述の図２の説明参照）。 Then, the first refrigerant A1 corresponding to point B3 passes through the first heat exchanger 31, the first expansion valve 41, and the second heat exchanger 32, and the first refrigerant A1 corresponding to point B3 changes into the refrigerant corresponding to points B4, B5, and B6 (see the explanation of Figure 2 above).
　次に、第１冷媒Ａ１の流れを示す。分岐部６５で分岐された第１冷媒Ａ１は、合流後冷媒に対して放熱する。第１冷媒Ａ１は、当該放熱により、第１冷媒Ａ１の比エンタルピは減少することから、点Ｂ８に対応する冷媒（低圧液冷媒）に変化する。その後、第１冷媒Ａ１は、第２膨張弁４２で減圧される。この減圧により、第１冷媒Ａ１は、点Ｂ９に対応する冷媒に変化する。 Next, the flow of the first refrigerant A1 is shown. The first refrigerant A1 branched at the branching section 65 dissipates heat to the refrigerant after merging. The specific enthalpy of the first refrigerant A1 decreases due to this heat dissipation, and the first refrigerant A1 changes to the refrigerant corresponding to point B8 (low-pressure liquid refrigerant). The first refrigerant A1 is then depressurized by the second expansion valve 42. Due to this depressurization, the first refrigerant A1 changes to the refrigerant corresponding to point B9.
　その後、点Ｂ９に対応する第１冷媒Ａ１（第３熱交換器３３および第２膨張弁４２を経由した第１冷媒）は、第４熱交換器３４において、第２冷媒Ａ２と熱交換される。具体的には、第４熱交換器３４は、第２冷媒Ａ２からの熱を、第１冷媒Ａ１に対して供給する。この熱の供給により、点Ｂ９に対応する第１冷媒Ａ１は、点Ｂ１０に対応する冷媒に変化する。点Ｂ１０に対応する第１冷媒Ａ１は、合流部６６に流入する。 Then, the first refrigerant A1 corresponding to point B9 (the first refrigerant that has passed through the third heat exchanger 33 and the second expansion valve 42) is heat exchanged with the second refrigerant A2 in the fourth heat exchanger 34. Specifically, the fourth heat exchanger 34 supplies heat from the second refrigerant A2 to the first refrigerant A1. Due to this supply of heat, the first refrigerant A1 corresponding to point B9 changes into the refrigerant corresponding to point B10. The first refrigerant A1 corresponding to point B10 flows into the junction 66.
　合流部６６においては、点Ｂ１０に対応する第１冷媒Ａ１と、点Ｂ６に対応する第２冷媒Ａ２とが合流することにより、点Ｂ７に対応する上述の合流後冷媒となる。第３熱交換器３３において、合流後冷媒は、第１冷媒Ａ１と熱交換を行う。具体的には、第３熱交換器３３は、第１冷媒Ａ１からの熱を、合流後冷媒に対して供給する。この供給により、合流後冷媒は、点Ｂ１に対応する冷媒に変化する。そして、点Ｂ１に対応する合流後冷媒は、再び圧縮機１に吸入される。 At the junction 66, the first refrigerant A1 corresponding to point B10 and the second refrigerant A2 corresponding to point B6 merge to become the above-mentioned merged refrigerant corresponding to point B7. In the third heat exchanger 33, the merged refrigerant exchanges heat with the first refrigerant A1. Specifically, the third heat exchanger 33 supplies heat from the first refrigerant A1 to the merged refrigerant. This supply changes the merged refrigerant into the refrigerant corresponding to point B1. The merged refrigerant corresponding to point B1 is then sucked back into the compressor 1.
　また、第２膨張弁４２が開放している状態において、暖房運転中の第１冷媒Ａ１の流れは、冷房運転中の第１冷媒Ａ１の流れと同じである。 In addition, when the second expansion valve 42 is open, the flow of the first refrigerant A1 during heating operation is the same as the flow of the first refrigerant A1 during cooling operation.
　図４は、第２膨張弁４２が開放している場合における、冷房運転中および暖房運転中のエンタルピ差を示す図である。まず、冷房運転中のエンタルピ差を説明する。図３でも説明したように、第４熱交換器３４において、第２冷媒Ａ２の熱は、第１冷媒Ａ１に放熱されている。したがって、冷房運転中において、第２膨張弁４２の開放時の第２熱交換器３２の出口側の冷媒（点Ｂ６に対応する冷媒）の比エンタルピは、第２膨張弁４２の閉塞時の第２熱交換器３２の出口側の冷媒（図２の点Ｃ１に対応する冷媒）の比エンタルピよりも小さくなる。また、冷房運転中において、第２膨張弁４２の開放時のエンタルピ差Δｈ３は、図４に示すように、点Ｂ６に対応する冷媒の比エンタルピから、点Ｂ５に対応する冷媒の比エンタルピが差引かれた差分値となる。したがって、空気調和装置１００は、冷房運転中において、第２膨張弁４２が開放したときの方が、第２膨張弁４２が閉塞したときよりもエンタルピ差を小さくすることができる。 FIG. 4 is a diagram showing the enthalpy difference during cooling operation and heating operation when the second expansion valve 42 is open. First, the enthalpy difference during cooling operation will be explained. As explained in FIG. 3, in the fourth heat exchanger 34, the heat of the second refrigerant A2 is dissipated to the first refrigerant A1. Therefore, during cooling operation, the specific enthalpy of the refrigerant (the refrigerant corresponding to point B6) at the outlet side of the second heat exchanger 32 when the second expansion valve 42 is open is smaller than the specific enthalpy of the refrigerant (the refrigerant corresponding to point C1 in FIG. 2) at the outlet side of the second heat exchanger 32 when the second expansion valve 42 is closed. Also, during cooling operation, the enthalpy difference Δh3 when the second expansion valve 42 is open is a difference value obtained by subtracting the specific enthalpy of the refrigerant corresponding to point B5 from the specific enthalpy of the refrigerant corresponding to point B6, as shown in FIG. 4. Therefore, during cooling operation, the air conditioning device 100 can reduce the enthalpy difference when the second expansion valve 42 is open compared to when the second expansion valve 42 is closed.
　次に、暖房運転中のエンタルピ差を説明する。図３でも説明したように、第４熱交換器３４において、第２冷媒Ａ２の熱は、第１冷媒Ａ１に放熱されている。したがって、暖房運転中において、第２膨張弁４２の開放時の第２熱交換器３２の入口側の冷媒（点Ｂ３に対応する冷媒）の比エンタルピは、第２膨張弁４２の閉塞時の第２熱交換器３２の入口側の冷媒（図２の点Ｃ２に対応する冷媒）の比エンタルピよりも小さくなる。また、暖房運転中において、第２膨張弁４２の開放時のエンタルピ差Δｈ４は、図４に示すように、点Ｂ３に対応する冷媒の比エンタルピから、点Ｂ４に対応する冷媒の比エンタルピが差引かれた差分値となる。したがって、空気調和装置１００は、暖房運転中において、第２膨張弁４２が開放したときの方が、第２膨張弁４２が閉塞したときよりもエンタルピ差を小さくすることができる。 Next, the enthalpy difference during heating operation will be described. As described in FIG. 3, in the fourth heat exchanger 34, the heat of the second refrigerant A2 is dissipated to the first refrigerant A1. Therefore, during heating operation, the specific enthalpy of the refrigerant (the refrigerant corresponding to point B3) on the inlet side of the second heat exchanger 32 when the second expansion valve 42 is open is smaller than the specific enthalpy of the refrigerant (the refrigerant corresponding to point C2 in FIG. 2) on the inlet side of the second heat exchanger 32 when the second expansion valve 42 is closed. Also, during heating operation, the enthalpy difference Δh4 when the second expansion valve 42 is open is a difference value obtained by subtracting the specific enthalpy of the refrigerant corresponding to point B4 from the specific enthalpy of the refrigerant corresponding to point B3, as shown in FIG. 4. Therefore, the air conditioning device 100 can reduce the enthalpy difference when the second expansion valve 42 is open during heating operation compared to when the second expansion valve 42 is closed.
　このように、空気調和装置１００は、冷房運転中および暖房運転中のいずれにおいても、第２膨張弁４２を開放することにより、エンタルピ差Δｈ３、Δｈ４を小さくすることができる。 In this way, the air conditioning device 100 can reduce the enthalpy differences Δh3 and Δh4 by opening the second expansion valve 42 during both cooling and heating operation.
　［低能力運転］
　次に、低能力運転を説明する。室内機１０２に流れる冷媒の循環流量Ｇｒと、上述のエンタルピ差とから第２熱交換器３２の交換熱量は、以下の式（１）により表される。 [Low capacity operation]
Next, the low capacity operation will be described. The amount of heat exchanged by the second heat exchanger 32 is expressed by the following formula (1) from the circulation flow rate Gr of the refrigerant flowing through the indoor unit 102 and the above-mentioned enthalpy difference.
　第２熱交換器３２の交換熱量＝Ｇｒ×Δｈ　　（１）
　また、上述のように、圧縮機１から吐出された冷媒は、分岐部６５において、第１冷媒Ａ１と第２冷媒Ａ２に分割される。そして、第２冷媒Ａ２のみが室内機１０２に流入し、第１冷媒Ａ１は室内機１０２に流入しない。したがって、空気調和装置１００は、第２膨張弁４２を開放することにより、室内機１０２に流れる冷媒の循環流量Ｇｒを減少させることができる。さらに、図２および図４でも説明したように、第２膨張弁４２を開放することにより、エンタルビ差Δｈを減少することができる。 Amount of heat exchanged by the second heat exchanger 32 = Gr × Δh (1)
As described above, the refrigerant discharged from the compressor 1 is divided into the first refrigerant A1 and the second refrigerant A2 at the branching section 65. Then, only the second refrigerant A2 flows into the indoor unit 102, and the first refrigerant A1 does not flow into the indoor unit 102. Therefore, by opening the second expansion valve 42, the air conditioning apparatus 100 can reduce the circulation flow rate Gr of the refrigerant flowing through the indoor unit 102. Furthermore, as described in Figures 2 and 4, by opening the second expansion valve 42, the enthalpy difference Δh can be reduced.
　このように、第２膨張弁４２を開放することにより、冷房運転および暖房運転のいずれにおいても、循環流量Ｇｒおよびエンタルビ差Δｈの双方を減少させることができる。よって、空気調和装置１００は、第２膨張弁４２を開放することにより、式（１）から第２熱交換器３２の交換熱量を減少させることができ、結果として低能力運転を実行することができる。 In this way, by opening the second expansion valve 42, it is possible to reduce both the circulation flow rate Gr and the enthalpy difference Δh in both cooling and heating operations. Therefore, by opening the second expansion valve 42, the air conditioning device 100 can reduce the amount of heat exchanged by the second heat exchanger 32 from equation (1), and as a result, can perform low-capacity operation.
　［制御装置の機能ブロック図］
　図５は、制御装置８の機能ブロック図である。制御装置８は、取得部１０３と、処理部１０４と、制御部１０６と、記憶部１０８とを有する。記憶部１０８には、設定温度１１０および開度テーブル１１２が格納されている。設定温度１１０は、ユーザにより設定される温度である。また、開度テーブル１１２については後述する。記憶部１０８は、本開示の「メモリ」に対応する。 [Functional block diagram of the control device]
5 is a functional block diagram of the control device 8. The control device 8 has an acquisition unit 103, a processing unit 104, a control unit 106, and a storage unit 108. A set temperature 110 and an opening degree table 112 are stored in the storage unit 108. The set temperature 110 is a temperature set by a user. The opening degree table 112 will be described later. The storage unit 108 corresponds to the "memory" in the present disclosure.
　室内温度センサ６１で検出された検出温度（室内温度）と、周波数センサ６３で検出された運転周波数とは、制御装置８に入力される。取得部１０３は、検出温度と、運転周波数とを取得する。検出温度と、運転周波数とは処理部１０４に出力される。処理部１０４は、第２膨張弁４２を開放するか否か、および第２膨張弁４２を開放する場合には該第２膨張弁４２の開度を特定する。 The detected temperature (room temperature) detected by the room temperature sensor 61 and the operating frequency detected by the frequency sensor 63 are input to the control device 8. The acquisition unit 103 acquires the detected temperature and the operating frequency. The detected temperature and the operating frequency are output to the processing unit 104. The processing unit 104 determines whether or not to open the second expansion valve 42, and if the second expansion valve 42 is opened, specifies the opening degree of the second expansion valve 42.
　まず、空気調和装置１００が冷房運転をしている場合を説明する。この場合には、制御装置８は、圧縮機１の運転周波数が最小値であるか否かを判断する。そして、圧縮機１の運転周波数が最小値であると判断した場合には、制御装置８は、検出温度が設定温度１１０よりも第１所定温度α以上、低いか否かを判断する。ここで、検出温度が設定温度よりも第１所定温度α以上、低い場合とは、圧縮機１の運転周波数が最小値であり、かつ冷房負荷が小さい場合である。したがって、この場合には、制御装置８は、低能力運転を実行するために第２膨張弁４２を開放することを決定する。 First, a case where the air conditioning device 100 is operating in cooling mode will be described. In this case, the control device 8 judges whether the operating frequency of the compressor 1 is at the minimum value. Then, if it is judged that the operating frequency of the compressor 1 is at the minimum value, the control device 8 judges whether the detected temperature is lower than the set temperature 110 by at least a first predetermined temperature α. Here, a case where the detected temperature is lower than the set temperature by at least a first predetermined temperature α means a case where the operating frequency of the compressor 1 is at the minimum value and the cooling load is small. Therefore, in this case, the control device 8 decides to open the second expansion valve 42 to perform low-capacity operation.
　また、第２膨張弁４２の開度が大きいほど、第１冷媒Ａ１の量を多くでき、結果として、第２冷媒Ａ２の量（つまり、上述の循環流量Ｇｒ）を少なくできる。つまり、第２膨張弁４２の開度が大きいほど、空気調和装置１００の運転能力を低下させることができる。 Furthermore, the greater the opening of the second expansion valve 42, the greater the amount of the first refrigerant A1, and as a result, the less the amount of the second refrigerant A2 (i.e., the above-mentioned circulation flow rate Gr). In other words, the greater the opening of the second expansion valve 42, the more the operating capacity of the air conditioning device 100 can be reduced.
　そこで、制御装置８は、第２膨張弁４２を開放することを決定された場合において、設定温度と検出温度との差分値が大きいほど、第２膨張弁４２の開度開度が大きくなるように、該開度を制御する。 When it is decided to open the second expansion valve 42, the control device 8 controls the opening degree of the second expansion valve 42 so that the opening degree increases as the difference between the set temperature and the detected temperature increases.
　図６は、開度テーブル１１２の一例である。開度テーブル１１２においては、図６の例では差分値ΔＴが大きいほど、開度Ｄが大きくなるように規定されている。図６の例では、差分値ΔＴ１に対して、開度Ｄ１が対応づけられている。また、差分値ΔＴ２に対して、開度Ｄ２が対応づけられている。また、差分値ΔＴ３に対して、開度Ｄ３が対応づけられている。ただし、ΔＴ１＞ΔＴ２＞ΔＴ３であり、Ｄ１＞Ｄ２＞Ｄ３である。処理部１０４は、図６の開度テーブルを参照して第２膨張弁４２の開度を決定する。なお、変形例として、処理部１０４は、開度を特定するための関数を用いるようにしてもよい。この関数は、差分値ΔＴが代入されると、開度Ｄを出力する。そして、この関数においては、代入される差分値ΔＴが大きいほど、大きな開度Ｄを出力する。 FIG. 6 is an example of the opening degree table 112. In the example of FIG. 6, the opening degree table 112 is stipulated such that the larger the difference value ΔT, the larger the opening degree D. In the example of FIG. 6, the opening degree D1 is associated with the difference value ΔT1. Furthermore, the opening degree D2 is associated with the difference value ΔT2. Furthermore, the opening degree D3 is associated with the difference value ΔT3. However, ΔT1>ΔT2>ΔT3, and D1>D2>D3. The processing unit 104 determines the opening degree of the second expansion valve 42 by referring to the opening degree table of FIG. 6. As a modified example, the processing unit 104 may use a function for specifying the opening degree. When the difference value ΔT is substituted, this function outputs the opening degree D. Furthermore, in this function, the larger the substituted difference value ΔT, the larger the opening degree D that is output.
　次に、空気調和装置１００が暖房運転をしている場合を説明する。この場合には、制御装置８は、圧縮機１の運転周波数が最小値であるか否かを判断する。そして、圧縮機１の運転周波数が最小値であると判断した場合には、制御装置８は、検出温度が設定温度１１０よりも第２所定温度β以上、高いか否かを判断する。ここで、検出温度が設定温度よりも第２所定温度β以上、高い場合とは、圧縮機１の運転周波数が最小値であり、かつ暖房負荷が小さい場合である。したがって、この場合には、制御装置８は、第２膨張弁４２を開放することを決定する。なお、第１所定温度αと、第２所定温度βとは同一としてもよく、異なっていてもよい。 Next, a case where the air conditioning device 100 is performing heating operation will be described. In this case, the control device 8 judges whether or not the operating frequency of the compressor 1 is at the minimum value. Then, if it is judged that the operating frequency of the compressor 1 is at the minimum value, the control device 8 judges whether or not the detected temperature is higher than the set temperature 110 by at least a second predetermined temperature β. Here, a case where the detected temperature is higher than the set temperature by at least a second predetermined temperature β means a case where the operating frequency of the compressor 1 is at the minimum value and the heating load is small. Therefore, in this case, the control device 8 decides to open the second expansion valve 42. Note that the first predetermined temperature α and the second predetermined temperature β may be the same or different.
　また、空気調和装置１００が暖房運転をしている場合においても、差分値と、上述の開度テーブルまたは上述の関数を用いて、開度を決定する。 Even when the air conditioning device 100 is in heating operation, the opening degree is determined using the difference value and the above-mentioned opening degree table or the above-mentioned function.
　以上のように、空気調和装置１００は、冷房運転中および暖房運転中のいずれであっても、第２膨張弁４２によって冷媒を第１冷媒Ａ１と第２冷媒Ａ２とに分割できる。したがって、室内機１０２（第２熱交換器３２）に流れる冷媒の循環流量Ｇｒ（式（１）参照）を減少させることができる。そして、冷房運転中および暖房運転中のいずれであっても、第３熱交換器３３は、第１冷媒Ａ１と、合流後冷媒との熱交換を行い、第４熱交換器３４は、第２冷媒Ａ２と、第３熱交換器３３を経由した第１冷媒Ａ１との熱交換を行う。したがって、空気調和装置１００は、暖房運転中および冷房運転中のいずれであっても、上述の断続運転の実行を抑制しつつ運転能力を低下させことができる。 As described above, the air conditioning device 100 can divide the refrigerant into the first refrigerant A1 and the second refrigerant A2 by the second expansion valve 42, whether in cooling operation or heating operation. Therefore, the circulation flow rate Gr (see formula (1)) of the refrigerant flowing through the indoor unit 102 (second heat exchanger 32) can be reduced. Then, whether in cooling operation or heating operation, the third heat exchanger 33 exchanges heat between the first refrigerant A1 and the refrigerant after the merger, and the fourth heat exchanger 34 exchanges heat between the second refrigerant A2 and the first refrigerant A1 that has passed through the third heat exchanger 33. Therefore, whether in heating operation or cooling operation, the air conditioning device 100 can reduce the operating capacity while suppressing the execution of the above-mentioned intermittent operation.
　また、冷房運転中および暖房運転中のいずれであっても、第４熱交換器３４は、第２冷媒Ａ２からの熱を、第３熱交換器３３を経由した第１冷媒Ａ１に対して供給する。したがって、点Ｃ２（図２参照）に対応する点Ｂ２は、点Ｂ３（図３および図４参照）にスライドされる。これとともに、点Ｃ１（図２参照）に対応する点Ｂ１は、点Ｂ６（図３および図４参照）にスライドされる。つまり、冷房運転中および暖房運転中のいずれであっても、第４熱交換器３４の熱交換により、エンタルピ差を減少させることができ、結果として運転能力を低下させることができる。 Furthermore, whether in cooling operation or heating operation, the fourth heat exchanger 34 supplies heat from the second refrigerant A2 to the first refrigerant A1 via the third heat exchanger 33. Therefore, point B2 corresponding to point C2 (see FIG. 2) slides to point B3 (see FIG. 3 and FIG. 4). At the same time, point B1 corresponding to point C1 (see FIG. 2) slides to point B6 (see FIG. 3 and FIG. 4). In other words, whether in cooling operation or heating operation, the enthalpy difference can be reduced by the heat exchange of the fourth heat exchanger 34, and as a result, the operating capacity can be reduced.
　また、冷房運転中および暖房運転中のいずれであっても、第３熱交換器３３は、第１冷媒Ａ１からの熱を、合流後冷媒に対して供給する。したがって、第３熱交換器３３の熱交換により、点Ｂ６は、点Ｃ１に対応する点Ｂ１にスライドされる。つまり、空気調和装置１００は、冷房運転中および暖房運転中のいずれであっても、圧縮機１に吸入される冷媒の第２膨張弁４２の開放時の熱状態を、第２膨張弁４２の閉塞時の熱状態と同様にすることができる。 Furthermore, whether in cooling operation or heating operation, the third heat exchanger 33 supplies heat from the first refrigerant A1 to the merged refrigerant. Therefore, due to the heat exchange in the third heat exchanger 33, point B6 slides to point B1, which corresponds to point C1. In other words, whether in cooling operation or heating operation, the air conditioning device 100 can make the thermal state of the refrigerant sucked into the compressor 1 when the second expansion valve 42 is open the same as the thermal state when the second expansion valve 42 is closed.
　たとえば、第２膨張弁４２が、第１冷媒Ａ１の経路において、圧縮機１と、第３熱交換器３３との間に配置される構成（以下、第２の比較例の構成）が考えられる。しかしながら、このような第２の比較例の構成では、内部熱交換器３３に流入する第１冷媒Ａ１の温度が、第２膨張弁４２などにより低下する。その結果、内部熱交換器３３における冷媒同士の温度差が低下することから、該内部熱交換器３３での交換熱量が低下するという問題が生じ得る。これに対し、本実施形態においては、第２膨張弁４２は、第１冷媒Ａ１の経路において第３熱交換器３３と第４熱交換器３４との間に設置されている。したがって、空気調和装置１００は、内部熱交換器３３に流入する第１冷媒Ａ１の温度の低下を抑制できることから、内部熱交換器３３での交換熱量の低下を抑制できる、という有利な効果を奏します。 For example, a configuration (hereinafter, the configuration of the second comparative example) in which the second expansion valve 42 is disposed between the compressor 1 and the third heat exchanger 33 in the path of the first refrigerant A1 is conceivable. However, in such a configuration of the second comparative example, the temperature of the first refrigerant A1 flowing into the internal heat exchanger 33 is lowered by the second expansion valve 42 and the like. As a result, the temperature difference between the refrigerants in the internal heat exchanger 33 is reduced, which may cause a problem that the amount of heat exchanged in the internal heat exchanger 33 is reduced. In contrast, in this embodiment, the second expansion valve 42 is disposed between the third heat exchanger 33 and the fourth heat exchanger 34 in the path of the first refrigerant A1. Therefore, the air conditioning device 100 has the advantageous effect of suppressing a decrease in the amount of heat exchanged in the internal heat exchanger 33 by suppressing a decrease in the temperature of the first refrigerant A1 flowing into the internal heat exchanger 33.
　また、冷媒運転および暖房運転のいずれであっても、制御装置８は、設定温度と検出温度との差分値が大きいほど、開度が大きくなるように、第２膨張弁４２を制御する。したがって、空気調和装置１００は、室内空間の熱負荷に応じた低能力運転を実行することができる。 In addition, in either refrigerant operation or heating operation, the control device 8 controls the second expansion valve 42 so that the opening degree increases as the difference between the set temperature and the detected temperature increases. Therefore, the air conditioning device 100 can perform low-capacity operation according to the thermal load of the indoor space.
　［処理フロー］
　図７は、制御装置８の処理を示すフローチャートである。図７の処理は、空気調和装置１００による冷房運転または暖房運転の実行中に所定期間（たとえば、１秒）毎に実行される処理である。まず、ステップＳ２において、制御装置８は、運転モードが冷房運転および暖房運転のいずれであるかを判断する。この判断は、たとえば、上述のモードフラグに基づいて実行される。運転モードが冷房運転である場合には、処理は、ステップＳ４に進み、運転モードが暖房運転である場合には、処理は、ステップＳ６に進む。 [Processing flow]
Fig. 7 is a flowchart showing the processing of the control device 8. The processing of Fig. 7 is executed at predetermined intervals (for example, one second) while the air conditioning device 100 is performing cooling operation or heating operation. First, in step S2, the control device 8 determines whether the operation mode is cooling operation or heating operation. This determination is executed, for example, based on the above-mentioned mode flag. If the operation mode is cooling operation, the processing proceeds to step S4, and if the operation mode is heating operation, the processing proceeds to step S6.
　図８は、ステップＳ４の冷房運転処理の流れを示すフローチャートである。ステップＳ４２において、圧縮機１の運転周波数が、最小値であるか否かを判断する。圧縮機１の運転周波数が、最小値でない場合には（ステップＳ４２でＮＯ）、処理は、ステップＳ４４に進む。ステップＳ４４においては、制御装置８は、第２膨張弁４２を閉塞する。そして、ステップＳ４の処理は、終了する。 FIG. 8 is a flowchart showing the flow of the cooling operation process in step S4. In step S42, it is determined whether the operating frequency of compressor 1 is at the minimum value. If the operating frequency of compressor 1 is not at the minimum value (NO in step S42), the process proceeds to step S44. In step S44, the control device 8 closes the second expansion valve 42. Then, the process of step S4 ends.
　また、ステップＳ４２において、圧縮機１の運転周波数が、最小値である場合には（ステップＳ４２でＹＥＳ）、処理は、ステップＳ４６に進む。ステップＳ４６においては、制御装置８は、室内温度（上述の検出温度）が設定温度よりも第１所定温度α以上、低いか否かを判断する。室内温度が設定温度よりも第１所定温度α以上、低い場合には（ステップＳ４６でＹＥＳ）、ステップＳ４８において、制御装置８は、第２膨張弁４２の開度を決定する。開度の決定は、たとえば、図６の開度テーブルが用いられる。 Also, in step S42, if the operating frequency of compressor 1 is at the minimum value (YES in step S42), the process proceeds to step S46. In step S46, the control device 8 determines whether the indoor temperature (the detected temperature described above) is lower than the set temperature by at least a first predetermined temperature α. If the indoor temperature is lower than the set temperature by at least a first predetermined temperature α (YES in step S46), in step S48, the control device 8 determines the opening degree of the second expansion valve 42. The opening degree is determined, for example, using the opening degree table in FIG. 6.
　そして、ステップＳ５０において制御装置８は、ステップＳ４８で決定された開度で第２膨張弁４２を開放する。そして、ステップＳ４の処理は、終了する。 Then, in step S50, the control device 8 opens the second expansion valve 42 to the opening degree determined in step S48. Then, the processing of step S4 ends.
　図９は、ステップＳ６の暖房運転処理の流れを示すフローチャートである。ステップＳ６２において、圧縮機１の運転周波数が、最小値であるか否かを判断する。圧縮機１の運転周波数が、最小値でない場合には（ステップＳ６２でＮＯ）、処理は、ステップＳ６４に進む。ステップＳ６４においては、制御装置８は、第２膨張弁４２を閉塞する。そして、ステップＳ６の処理は、終了する。 FIG. 9 is a flowchart showing the flow of the heating operation process in step S6. In step S62, it is determined whether the operating frequency of compressor 1 is at the minimum value. If the operating frequency of compressor 1 is not at the minimum value (NO in step S62), the process proceeds to step S64. In step S64, the control device 8 closes the second expansion valve 42. Then, the process of step S6 ends.
　また、ステップＳ６２において、圧縮機１の運転周波数が、最小値である場合には（ステップＳ６２でＹＥＳ）、処理は、ステップＳ６６に進む。ステップＳ６６においては、制御装置８は、室内温度（上述の検出温度）が設定温度よりも第２所定温度β以上、高いか否かを判断する。室内温度が設定温度よりも第２所定温度β以上、高い場合には（ステップＳ６６でＹＥＳ）、ステップＳ６８において、制御装置８は、第２膨張弁４２の開度を決定する。開度の決定は、たとえば、図６の開度テーブルが用いられる。 Also, in step S62, if the operating frequency of compressor 1 is at the minimum value (YES in step S62), the process proceeds to step S66. In step S66, the control device 8 determines whether the indoor temperature (the detected temperature described above) is higher than the set temperature by at least a second predetermined temperature β. If the indoor temperature is higher than the set temperature by at least a second predetermined temperature β (YES in step S66), in step S68, the control device 8 determines the opening degree of the second expansion valve 42. The opening degree is determined, for example, using the opening degree table in FIG. 6.
　そして、ステップＳ７０において制御装置８は、ステップＳ６８で決定された開度で第２膨張弁４２を開放する。そして、ステップＳ６の処理は、終了する。 Then, in step S70, the control device 8 opens the second expansion valve 42 to the opening degree determined in step S68. Then, the processing of step S6 ends.
　今回開示された実施の形態はすべての点で例示であって制限的なものではないと考えられるべきである。本開示の範囲は上記した説明ではなくて請求の範囲によって示され、請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。 The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The scope of the present disclosure is indicated by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.
　１　圧縮機、２　四方弁、６　室外送風機、７　室内送風機、８　制御装置、１０　冷媒回路、２１　ガス管、２２　液管、３１　第１熱交換器、３２　第２熱交換器、３３　第３熱交換器、３４　第４熱交換器、４１　第１膨張弁、４２　第２膨張弁、６１　室内温度センサ、６３　周波数センサ、６５　分岐部、６６　合流部、８１　第１配管、８２　第２配管、８８　メモリ、１００　空気調和装置、１０１　室外機、１０２　室内機、１０３　取得部、１０４　処理部、１０６　制御部、１０８　記憶部、１１０　設定温度、１１２　開度テーブル。 1 compressor, 2 four-way valve, 6 outdoor blower, 7 indoor blower, 8 control device, 10 refrigerant circuit, 21 gas pipe, 22 liquid pipe, 31 first heat exchanger, 32 second heat exchanger, 33 third heat exchanger, 34 fourth heat exchanger, 41 first expansion valve, 42 second expansion valve, 61 indoor temperature sensor, 63 frequency sensor, 65 branching section, 66 junction section, 81 first pipe, 82 second pipe, 88 memory, 100 air conditioning device, 101 outdoor unit, 102 indoor unit, 103 acquisition section, 104 processing section, 106 control section, 108 memory section, 110 set temperature, 112 opening degree table.

Claims (5)

  1. 　冷媒を圧縮する圧縮機と、
    　第１空間の空気と冷媒との熱交換を行う第１熱交換器と、
    　冷媒を膨張させる第１膨張弁と、
    　第２空間の空気と冷媒との熱交換を行う第２熱交換器と、
    　前記圧縮機、前記第１熱交換器、前記第１膨張弁、および前記第２熱交換器を接続する第１配管と、
    　前記圧縮機、前記第１熱交換器、前記第１膨張弁、および前記第２熱交換器を接続せずに、前記圧縮機の吸入側と、前記圧縮機の吐出側とを接続する第２配管と、
    　前記圧縮機から吐出された冷媒の一部を第１冷媒として、前記第２配管に引込む第２膨張弁と、
    　前記第１冷媒と、前記圧縮機から吐出された冷媒のうち前記第１冷媒とは異なる第２冷媒とが合流する合流部と、
    　前記第１冷媒と、前記合流部で合流された冷媒との熱交換を行う第３熱交換器と、
    　前記第２冷媒と、前記第３熱交換器を経由した前記第１冷媒との熱交換を行う第４熱交換器とを備える、空気調和装置。     A compressor that compresses a refrigerant;
    a first heat exchanger that exchanges heat between the air in the first space and the refrigerant;
    a first expansion valve for expanding a refrigerant;
    a second heat exchanger that exchanges heat between the air in the second space and the refrigerant;
    a first pipe connecting the compressor, the first heat exchanger, the first expansion valve, and the second heat exchanger;
    a second pipe that connects the suction side of the compressor and the discharge side of the compressor without connecting the compressor, the first heat exchanger, the first expansion valve, and the second heat exchanger;
    a second expansion valve that draws a portion of the refrigerant discharged from the compressor into the second pipe as a first refrigerant;
    a confluence portion where the first refrigerant and a second refrigerant different from the first refrigerant discharged from the compressor are confluenced;
    a third heat exchanger that performs heat exchange between the first refrigerant and the refrigerant that is joined at the joining portion;
    an air conditioning apparatus comprising: a fourth heat exchanger that performs heat exchange between the second refrigerant and the first refrigerant that has passed through the third heat exchanger.
  2. 　前記空気調和装置が冷房運転中および暖房運転中のいずれであっても、
    　前記第３熱交換器は、前記第１冷媒からの熱を、前記合流部で合流された冷媒に対して供給し、
    　前記第４熱交換器は、前記第２冷媒からの熱を、前記第３熱交換器を経由した前記第１冷媒に対して供給する、請求項１に記載の空気調和装置。     Whether the air conditioner is in cooling operation or heating operation,
    The third heat exchanger supplies heat from the first refrigerant to the refrigerant joined at the joining portion,
    The air-conditioning apparatus according to claim 1 , wherein the fourth heat exchanger supplies heat from the second refrigerant to the first refrigerant that has passed through the third heat exchanger.
  3. 　前記第２膨張弁は、前記第３熱交換器と前記第４熱交換器との間に設置されている、請求項１または請求項２に記載の空気調和装置。 The air conditioner according to claim 1 or 2, wherein the second expansion valve is installed between the third heat exchanger and the fourth heat exchanger.
  4. 　前記空気調和装置は、さらに、
    　設定温度を記憶するメモリと、
    　前記第２空間の温度を検出温度として検出するセンサと、
    　前記第２膨張弁の開度を制御する制御装置とを備え、
    　前記制御装置は、前記空気調和装置が冷房運転が実行しており、前記圧縮機の運転周波数が最小値であり、かつ前記検出温度が前記設定温度よりも第１所定温度以上低い場合において、前記設定温度と前記検出温度との差分値が大きいほど、前記開度が大きくなるように、前記第２膨張弁を制御する、請求項１～請求項３のいずれか１項に記載の空気調和装置。     The air conditioning device further comprises:
    A memory for storing the set temperature;
    a sensor that detects a temperature of the second space as a detection temperature;
    a control device that controls an opening degree of the second expansion valve,
    An air conditioning apparatus as described in any one of claims 1 to 3, wherein the control device controls the second expansion valve so that the opening degree becomes larger the greater the difference value between the set temperature and the detected temperature when the air conditioning apparatus is performing cooling operation, the operating frequency of the compressor is at a minimum value, and the detected temperature is lower than the set temperature by a first predetermined temperature or more.
  5. 　前記空気調和装置は、さらに、
    　設定温度を記憶するメモリと、
    　前記第２空間の温度を検出温度として検出するセンサと、
    　前記第２膨張弁の開度を制御する制御装置とを備え、
    　前記制御装置は、前記空気調和装置が暖房運転が実行しており、前記圧縮機の運転周波数が最小値であり、かつ前記検出温度が前記設定温度よりも第２所定温度以上高い場合において、前記設定温度と前記検出温度との差分値が大きいほど、前記開度が大きくなるように、前記第２膨張弁を制御する、請求項１～請求項３のいずれか１項に記載の空気調和装置。     The air conditioning device further comprises:
    A memory for storing the set temperature;
    a sensor that detects a temperature of the second space as a detection temperature;
    a control device that controls an opening degree of the second expansion valve,
    An air conditioning apparatus as described in any one of claims 1 to 3, wherein the control device controls the second expansion valve so that the opening degree becomes larger the greater the difference value between the set temperature and the detected temperature when the air conditioning apparatus is performing heating operation, the operating frequency of the compressor is at a minimum value, and the detected temperature is higher than the set temperature by at least a second predetermined temperature.
PCT/JP2022/048399 2022-12-27 2022-12-27 Air conditioning device WO2024142327A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011122767A (en) * 2009-12-10 2011-06-23 Mitsubishi Heavy Ind Ltd Air conditioner and method for detecting refrigerant content of air conditioner
JP2015039999A (en) * 2013-08-23 2015-03-02 サンデン株式会社 Air conditioner for vehicle
JP2019158189A (en) * 2018-03-09 2019-09-19 パナソニックＩｐマネジメント株式会社 Refrigeration cycle device and hot water generation device including the same
JP2020143879A (en) * 2019-03-08 2020-09-10 株式会社富士通ゼネラル Air conditioner

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011122767A (en) * 2009-12-10 2011-06-23 Mitsubishi Heavy Ind Ltd Air conditioner and method for detecting refrigerant content of air conditioner
JP2015039999A (en) * 2013-08-23 2015-03-02 サンデン株式会社 Air conditioner for vehicle
JP2019158189A (en) * 2018-03-09 2019-09-19 パナソニックＩｐマネジメント株式会社 Refrigeration cycle device and hot water generation device including the same
JP2020143879A (en) * 2019-03-08 2020-09-10 株式会社富士通ゼネラル Air conditioner

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