Air conditioning device

Abstract

An air conditioning device is provided with an outdoor unit, a plurality of indoor units, a plurality of liquid refrigerant flow paths and a plurality of gas refrigerant flow paths, and a shut-off valve device that is provided between the outdoor unit and the plurality of indoor units and is capable of controlling the flow of refrigerant in the liquid refrigerant flow paths and the gas refrigerant flow paths. The shut-off valve device is provided with: a liquid-side control valve which is provided in common to a plurality of liquid refrigerant flow paths and which is capable of shutting off the flow of refrigerant in relation to the plurality of liquid refrigerant flow paths; gas-side control valves provided in the plurality of gas refrigerant flow paths, respectively, and capable of blocking the flow of the refrigerant with respect to the plurality of gas refrigerant flow paths; a bypass path connecting a portion of the liquid refrigerant flow path closer to the indoor unit than the liquid-side control valve and a portion of the gas refrigerant flow path closer to the indoor unit than the gas-side control valve; and a pressure release valve which is provided in the bypass path, is in a normally closed state, and, when the pressure is equal to or greater than a preset pressure, operates without using electric power by means of the pressure, and is in an open state, thereby releasing the pressure of the refrigerant from the liquid refrigerant flow path to the gas refrigerant flow path.

Description

Technical Field

[0001] Embodiments of the present invention relate to air conditioning devices. Background Technology

[0002] In recent years, the use of so-called low-GWP refrigerants, which have a low Global Warming Potential (GWP), has been increasing as refrigerants for air conditioning systems. However, low-GWP refrigerants are often flammable refrigerants containing trace amounts of flammable material. Therefore, in the event of a leak from the equipment when using flammable refrigerants, safety must be ensured.

[0003] Therefore, in places like Europe, safety measures are specified based on factors such as the amount of refrigerant incorporated into the overall air conditioning unit and the volume of the room where the indoor unit is located. Safety measures include, for example, installing a shut-off device between the indoor and outdoor units to cut off the refrigerant supply to the indoor unit upon detection of a refrigerant leak.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2018 / 062528 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, there is still room for improvement in terms of safety and reliability in the previous configuration.

[0009] Therefore, an air conditioning device is provided that can improve safety and reliability in the event of refrigerant leakage.

[0010] Methods for solving problems

[0011] The air conditioning device of the embodiment includes: an outdoor unit having an outdoor heat exchanger and a compressor; multiple indoor units having indoor heat exchangers connected to the outdoor heat exchanger and the compressor; multiple liquid refrigerant flow paths and multiple gaseous refrigerant flow paths connecting the outdoor unit and the multiple indoor units, wherein the multiple liquid refrigerant flow paths are for liquid refrigerant to pass through, and the multiple gaseous refrigerant flow paths are for gaseous refrigerant to pass through; and a shut-off valve device disposed between the outdoor unit and the multiple indoor units, capable of controlling the flow of refrigerant in the liquid refrigerant flow paths and the gaseous refrigerant flow paths. The shut-off valve device includes: a liquid-side control valve, commonly disposed in multiple liquid refrigerant flow paths, capable of shutting off refrigerant flow relative to the multiple liquid refrigerant flow paths; a gas-side control valve, respectively disposed in multiple gas refrigerant flow paths, capable of shutting off refrigerant flow relative to the multiple gas refrigerant flow paths; a bypass passage connecting the portion of the liquid refrigerant flow path closer to the indoor unit side than the liquid-side control valve to the portion of the gas refrigerant flow path closer to the indoor unit side than the gas-side control valve; and a pressure relief valve disposed in the bypass passage, normally in a closed state, but opening when a preset pressure is reached, without the use of electricity, to release refrigerant pressure from the liquid refrigerant flow path to the gas refrigerant flow path. Attached Figure Description

[0012] Figure 1 This is a refrigeration cycle diagram illustrating an example of an air conditioning device according to one embodiment.

[0013] Figure 2 This is a refrigeration cycle diagram showing the flow of refrigerant in an air conditioning device under full heating operation in one embodiment.

[0014] Figure 3 This is a refrigeration cycle diagram showing the flow of refrigerant in an air conditioning device under full refrigeration operation in one embodiment.

[0015] Figure 4 This is a refrigeration cycle diagram illustrating an example of refrigerant flow in an air conditioning device according to one embodiment, where both cooling and heating are performed simultaneously.

[0016] Figure 5 This is a block diagram illustrating an example of the electrical configuration of an air conditioning device according to one embodiment.

[0017] Figure 6 This is a diagram illustrating an example of the arrangement of the bypass passage and pressure relief valve of an air conditioning device according to one embodiment.

[0018] Figure 7This is a refrigeration cycle diagram illustrating an example of refrigerant flow in a multi-split air conditioning unit where a refrigerant recovery process has been performed. Detailed Implementation

[0019] Hereinafter, one embodiment will be described with reference to the accompanying drawings.

[0020] Figure 1 The air conditioning unit 1 shown is a multi-split air conditioning unit, which has multiple indoor units relative to a single outdoor unit and is capable of operating in full heating mode, full cooling mode, and simultaneous heating and cooling mode. Full heating mode refers to the operation mode in which all indoor units operate in heating mode. Full cooling mode refers to the operation mode in which all indoor units operate in cooling mode. Simultaneous heating and cooling mode refers to the operation mode in which indoor units operating in cooling mode and indoor units operating in heating mode coexist. In the following description, full heating mode, full cooling mode, and simultaneous heating and cooling mode are sometimes collectively referred to as air conditioning operation. Furthermore, a multi-split air conditioning unit refers to a configuration in which multiple indoor units operate within a single outdoor unit.

[0021] The air conditioning unit 1 is configured to operate multiple, for example, three indoor units 201, 202, and 203 using one outdoor unit 10. The air conditioning unit 1 includes, for example, one outdoor unit 10, multiple indoor units 201-203, and a shut-off valve device 30. The outdoor unit 10, each indoor unit 201-203, and the shut-off valve device 30 constitute a refrigeration cycle capable of circulating refrigerant.

[0022] In this embodiment, the shut-off valve device 30 is configured as a multi-port shut-off valve device. A multi-port shut-off valve device refers to a shut-off valve device having multiple sets of refrigerant piping pairs for connecting to the indoor units, i.e., inlet and outlet. Furthermore, a shut-off valve device having only one set of port pairs for connecting to the indoor units is referred to as a single-port shut-off valve device. For example, the shut-off valve device 30 of this embodiment has three sets of refrigerant piping pairs for connecting three indoor units 201 to 203, namely, the set of refrigerant pipes 461 and 43, the set of refrigerant pipes 462 and 44, and the set of refrigerant pipes 463 and 45.

[0023] Outdoor unit 10 is installed outdoors. For example... Figure 1 As shown in the refrigeration cycle diagram, the outdoor unit 10 includes an outdoor heat exchanger 11, an outdoor fan 12, an outdoor expansion valve 13, a compressor 14, a first switching valve 15, and a second switching valve 16. The outdoor heat exchanger 11 functions to exchange heat between the refrigerant passing through it and the outside air. The outdoor fan 12 functions to promote heat exchange in the outdoor heat exchanger 11 by supplying air to it. A slightly flammable, combustible refrigerant is used as the refrigerant in the refrigeration cycle. In this embodiment, for example, slightly flammable R32 is used as the refrigerant.

[0024] An outdoor expansion valve 13 is installed on the liquid-side refrigerant pipe 46 from the outdoor unit 10 toward the indoor units 201-203. The outdoor expansion valve 13 functions to: reduce refrigerant pressure by adjusting the flow path area of ​​the refrigerant passing through its interior; and to adjust the flow rate and pressure of refrigerant flowing out of or into the outdoor heat exchanger 11. For example, the outdoor expansion valve 13... Figure 5 As shown, it consists of an electronic expansion valve that can be driven by receiving electrical signals from a computer called an MCU (Microcontroller Unit) installed in the outdoor control unit 17 of the outdoor unit 10. Furthermore, MCU is an abbreviation for Microcontroller Unit.

[0025] The first switching valve 15 and the second switching valve 16 have the function of switching the flow direction of the refrigerant in the refrigeration cycle, that is, the flow direction of the refrigerant discharged from the compressor 14. The first switching valve 15 and the second switching valve 16 are, for example, four-way valves driven by receiving electrical signals, but as long as they can form the same refrigerant flow, multiple valves other than four-way valves can also be combined.

[0026] Compressor 14 compresses the refrigerant flowing within the refrigeration cycle, for example, by... Figure 1 The compressor 14 discharges refrigerant in the direction indicated by the hollow arrow. The compressor 14 discharges refrigerant according to the switching states of the first switching valve 15 and the second switching valve 16, such as... Figure 2 The refrigerant is drawn into the outdoor heat exchanger 11 side and discharged towards the shut-off valve device 30 side, or as shown. Figure 3 The device draws in refrigerant from the shut-off valve device 30 side and discharges the drawn-in refrigerant to the outdoor heat exchanger 11 side.

[0027] Each indoor unit 201 to 203 is installed in the room where the air conditioner will operate. Each indoor unit 201 to 203 has an indoor heat exchanger 21, an indoor fan 22, an indoor expansion valve 23, and a leakage sensor 24. Each indoor unit 201 to 203 can basically be configured the same, but the performance of the indoor heat exchanger 21, indoor expansion valve 23, indoor fan 22, and leakage sensor 24 can be appropriately modified according to the volume of the space where they are installed.

[0028] The indoor heat exchanger 21 facilitates heat exchange between the refrigerant passing through its interior and the air in the room where indoor units 201-203 are located. The indoor heat exchanger 21 is connected to the outdoor heat exchanger 11 and the compressor 14, allowing the refrigerant to circulate between the outdoor heat exchanger 11, the indoor heat exchanger 21, and the compressor 14. The indoor fan 22 functions to promote heat exchange in the indoor heat exchanger 21 by supplying air to it, and to supply the room with air that has been conditioned by the indoor heat exchanger 21.

[0029] The indoor expansion valve 23 has the function of controlling the refrigerant flow rate by adjusting the flow path area of ​​the refrigerant passing through the indoor expansion valve 23. Like the outdoor expansion valve 13, the indoor expansion valve 23 can be, for example, an electronic expansion valve that is driven by receiving electrical signals from a computer such as an MCU from the indoor control unit 25 provided in each indoor unit 201 to 203.

[0030] like Figure 5 As shown, each indoor unit 201-203 has an indoor control unit 25. Additionally, although not shown in detail, the shut-off valve device 30 also has a control unit, which is configured with a computer. The outdoor control unit 17 of the outdoor unit 10, the indoor control units 25 of each indoor unit 201-203, and the (not shown) control unit of the shut-off valve device 30 are interconnected via communication lines to exchange various information.

[0031] Leakage sensor 24 has the function of detecting refrigerant leakage in each indoor unit 201-203. Leakage sensor 24 can be assembled inside each indoor unit 201-203, or it can be independently installed as a leakage sensor unit in the indoor space of each room where each indoor unit 201-203 is installed. In this embodiment, leakage sensor 24 is installed in each indoor unit 201-203. Leakage sensor 24 can be, for example, a semiconductor gas sensor. Leakage sensor 24 has the ability to detect the refrigerant, in this case R32, sealed in the refrigeration cycle. For example, for refrigerant concentrations of approximately 300-30,000 ppm in the air, leakage sensor 24 outputs an electrical signal that changes linearly according to the refrigerant concentration. If the detected concentration exceeds a predetermined value, it notifies the corresponding indoor unit 201-203 and outdoor unit 10 that a refrigerant leak has occurred.

[0032] A shut-off valve device 30 is disposed between the outdoor unit 10 and each of the indoor units 201-203. That is, the outdoor unit 10 and each of the indoor units 201-203 are connected via the shut-off valve device 30. The shut-off valve device 30 has multiple gas control valve units 31, 32, and 33, corresponding to the multiple indoor units 201-203 connected to the shut-off valve device 30, and one liquid-side control valve 34. In the following description, when distinguishing between the gas control valve units 31, 32, and 33, they are sometimes referred to as the first gas control valve unit 31, the second gas control valve unit 32, and the third gas control valve unit 33, respectively.

[0033] Each gas control valve unit 31-33 has two gas-side control valves selected from 311, 312, 321, 322, 331, and 332. Alternatively, each gas control valve unit 31-33 may be configured to have one gas-side control valve. The gas-side control valves 311, 312, 321, 322, 331, and 332 are respectively located on the paths of the gas-side refrigerant pipes 431, 432, 441, 442, 451, and 452, and have the function of controlling the flow of gaseous refrigerant.

[0034] Gas-side refrigerant pipes 431, 432, 441, 442, 451, and 452 are part of the refrigerant flow path connecting the indoor heat exchangers 21 of indoor units 201-203 to the compressor 14, allowing gaseous refrigerant to pass through. Gas-side refrigerant pipes 431, 432, 441, 442, 451, and 452 merge to form gas-side refrigerant pipes 43, 44, and 45, which are connected to the indoor heat exchangers 21 of each indoor unit 201-203. In this case, liquid-side refrigerant pipes 461-463 and gas-side refrigerant pipes 43-45, connected to each indoor unit 201-203, respectively constitute the refrigerant flow path connected to each indoor unit 201-203.

[0035] In the following description, when distinguishing between each liquid-side refrigerant pipe 461-463 and each gas-side refrigerant pipe 43-45, they are sequentially referred to as the first liquid-side refrigerant pipe 461 and the first gas-side refrigerant pipe 43, the second liquid-side refrigerant pipe 462 and the second gas-side refrigerant pipe 44, and the third liquid-side refrigerant pipe 463 and the third gas-side refrigerant pipe 45, starting from the side closest to the liquid-side control valve 34. Furthermore, when distinguishing between each indoor unit 201, 202, and 203, the indoor unit connected to the first liquid-side refrigerant pipe 461 and the first gas-side refrigerant pipe 43 is sometimes referred to as the first indoor unit 201, the indoor unit connected to the second liquid-side refrigerant pipe 462 and the second gas-side refrigerant pipe 44 is referred to as the second indoor unit 202, and the indoor unit connected to the third liquid-side refrigerant pipe 463 and the third gas-side refrigerant pipe 45 is referred to as the third indoor unit 203.

[0036] Gas-side control valves 311, 312, 321, 322, 331, and 332 can be configured as electronically controlled valves, for example, that are driven by receiving electrical signals and capable of so-called electronic control. Based on electrical control from the control unit of the shut-off valve device 30, the gas-side control valves 311, 312, 321, 322, 331, and 332 can adjust their opening degree, i.e., the flow rate of refrigerant flowing in the corresponding gas-side refrigerant pipes 431, 432, 441, 442, 451, and 452.

[0037] In each gas control valve unit 31, 32, 33, one of the two gas-side control valves 311, 312, 321, 322, 331, 332 corresponds to high-pressure gas, and the other corresponds to low-pressure gas. In this embodiment, for example, gas-side control valves 311, 321, 331 correspond to high-pressure gas, and gas-side control valves 312, 322, 332 correspond to low-pressure gas. By closing the gas-side control valves 311, 312, 321, 322, 331, 332 in each gas control valve unit 31, 32, 33, the air conditioning unit 1 can cut off the refrigerant flowing between the indoor heat exchanger 21 and the compressor 14 in each indoor unit 201-203, that is, the refrigerant flowing in the gas-side refrigerant pipes 431, 432, 441, 442, 451, 452.

[0038] A liquid-side control valve 34 is positioned midway along the liquid-side refrigerant pipe 46 connecting the outdoor heat exchanger 11 to the indoor heat exchangers 21 of each indoor unit 201-203, and functions to control the flow of liquid refrigerant. The liquid-side refrigerant pipe 46 is the refrigerant flow path connecting the outdoor heat exchanger 11 to the indoor heat exchangers 21 of each indoor unit 201-203, allowing liquid refrigerant to pass through. Relative to the liquid-side control valve 34, the liquid-side refrigerant pipe 46 branches into liquid-side refrigerant pipes 461-463 on the indoor unit 201-203 side, each connected to one end of the indoor heat exchanger 21 of each indoor unit 201-203.

[0039] Regarding the shut-off valve device 30, this embodiment illustrates an example that can connect three indoor units 201 to 203, but there are also models that can connect two or more indoor units. In any model, only one liquid-side control valve 34 is installed in the liquid-side refrigerant pipe 46. This configuration simplifies the refrigerant circuit and piping layout. Furthermore, the number of gas-side control valves 311, 312, 321, 322, 331, and 332 needs to be twice the number of indoor units 201 to 203 connected.

[0040] The liquid-side control valve 34 can be, for example, an electronically controlled valve that is driven by an electrical signal and is capable of so-called electronic control. Based on the electrical control from the control unit of the shut-off valve device 30, the liquid-side control valve 34 can adjust its opening degree, i.e., the flow rate of the refrigerant flowing in the liquid-side refrigerant lines 46, 461 to 463, and has the function of completely shutting off the flow of refrigerant in the liquid-side refrigerant lines 46, 461 to 463.

[0041] like Figure 5 As shown, the air conditioning unit 1 also includes a backup power supply 37, such as a battery. The backup power supply 37 may be configured as an element of the shut-off valve device 30, or it may be configured as an element different from the shut-off valve device 30. The backup power supply 37 has the function of supplying power to the gas-side control valves 311, 312, 321, 322, 331, 332 and the liquid-side control valve 34 in the event of a power outage, thereby closing these valves.

[0042] The shut-off valve device 30 also includes a bypass passage 35 and a pressure relief valve 36. The bypass passage 35 and the pressure relief valve 36 are connected to one of the plurality of gas control valve units 31 to 33. The bypass passage 35 is located at the position where the first liquid-side refrigerant pipe 461, 462, 463, which serves as a liquid-side refrigerant flow path, and the first gas-side refrigerant pipe 43, 44, 45, which serves as a gas-side refrigerant flow path, are closest to the liquid-side control valve 34.

[0043] That is, in this embodiment, the bypass passage 35 and the pressure relief valve 36 are provided in the first gas control valve unit 31. The bypass passage 35 connects the liquid-side refrigerant pipe 461, which serves as the liquid-side refrigerant flow path, and the gas-side refrigerant pipe 43, which serves as the gas-side refrigerant flow path, through the indoor unit 201. Specifically, the bypass passage 35 connects the liquid-side control valve 34 in the liquid-side refrigerant pipe 461 on the side closest to the indoor unit 201 to the gas-side control valves 311 and 312 in the gas-side refrigerant pipe 43 on the side closest to the indoor unit 201.

[0044] A pressure relief valve 36 is provided on the bypass passage 35. The pressure relief valve 36 can be, for example, a mechanical valve that operates under pressure without receiving electrical power. The pressure relief valve 36 can also be a check valve that, when the pressure difference between the liquid-side refrigerant line 461 and the gas-side refrigerant line 43 exceeds a predetermined value, allows refrigerant to flow from the liquid-side refrigerant line 461 to the gas-side refrigerant line 43, but prevents refrigerant from flowing from the gas-side refrigerant line 43 to the liquid-side refrigerant line 461. The pressure relief valve 36 is normally set to be in the closed state.

[0045] When the pressure difference between the gas-side refrigerant line 43 and the liquid-side refrigerant line 461 exceeds a predetermined pressure, that is, when the pressure in the liquid-side refrigerant line 461 relative to the gas-side refrigerant line 43 exceeds a predetermined pressure, the pressure relief valve 36 operates without electricity, opening to the open state. This allows a portion of the refrigerant pressure to be released from the liquid-side refrigerant line 461 to the gas-side refrigerant line 43. The operating pressure of the pressure relief valve 36, the pressure required to open, is set, for example, to approximately 4 MPa. In this case, the operating pressure of the pressure relief valve 36 is set to a value lower than the pressure resistance of the indoor expansion valve 23. Therefore, even if the liquid-side refrigerant line 461 becomes liquid-sealed and the pressure rises, the pressure relief valve 36 can be opened before the indoor expansion valve 23 is damaged, reducing the pressure within the liquid-side refrigerant line 461.

[0046] like Figure 6 As shown, the pressure relief valve 36 is configured, for example, as an elongated strip shape in one direction. In this case, the pressure relief valve 36 is positioned with its length direction horizontal. Therefore, compared to the case where the pressure relief valve 36 is positioned with its length direction vertical, the shut-off valve device 30 has a smaller dimension in the height direction. Therefore, it is easy to install the shut-off valve device 30 in a space with a small dimension in the height direction, such as the back of a ceiling.

[0047] Furthermore, the bypass passage 35 is configured such that it does not connect the liquid-side refrigerant pipe 461 and the gas-side refrigerant pipe 43 in a straight line, i.e., with the shortest distance, but instead passes through the upper side of the liquid-side refrigerant pipe 461 and the gas-side refrigerant pipe 43 in the vertical direction. Moreover, the pressure relief valve 36 is positioned in the bypass passage 35 at a position higher in the vertical direction than the connection portion 351 between the bypass passage 35 and the liquid-side refrigerant pipe 461 and the connection portion 352 between the bypass passage 35 and the gas-side refrigerant pipe 43.

[0048] Next, in Figures 2 to 4 as well as Figure 7 The flow of refrigerant during the operation of air conditioning unit 1 is explained. Additionally, in... Figures 2 to 4 and Figure 7 In the diagram, the thick black solid lines and hollow arrows in the refrigerant flow path are used to illustrate the main flow of refrigerant in each operating section, which sometimes differs from the actual refrigerant flow. That is, in reality, sometimes the areas not indicated by the thick black solid lines are also filled with refrigerant.

[0049] When air conditioning unit 1 is operating in full heating mode, such as Figure 2As shown, the first switching valve 15 is switched to connect the suction side of the compressor 14 to the outdoor heat exchanger 11, and the second switching valve 16 is switched to connect the discharge side of the compressor 14 to the indoor heat exchangers 21 of each indoor unit 201-203. During full heating operation, the outdoor heat exchanger 11 functions as an evaporator, and the indoor heat exchangers 21 of all indoor units 201-203 function as condensers.

[0050] In this situation, the air conditioning unit 1 closes the gas-side control valves 312, 322, and 332 corresponding to the low-pressure gas, and opens the gas-side control valves 311, 321, and 331 corresponding to the high-pressure gas. Furthermore, each indoor unit 201 to 203 adjusts its heating output by controlling the opening degree of its own indoor expansion valve 23.

[0051] When air conditioning unit 1 is operating in full cooling mode, such as Figure 3 As shown, the first switching valve 15 is switched to connect the discharge side of the compressor 14 to the outdoor heat exchanger 11, and the second switching valve 16 is switched to connect the suction side of the compressor 14 to the indoor heat exchangers 21 of each indoor unit 201-203. During full cooling operation, the outdoor heat exchanger 11 functions as a condenser, and the indoor heat exchangers 21 of all indoor units 201-203 function as evaporators.

[0052] In this case, regarding the shut-off valve device 30, the air conditioning unit 1 opens the gas-side control valves 312, 322, and 332 corresponding to the low-pressure gas, and closes the gas-side control valves 311, 321, and 331 corresponding to the high-pressure gas. Furthermore, each indoor unit 201-203 adjusts its cooling output by controlling the opening degree of its own indoor expansion valve 23.

[0053] When the air conditioning unit 1 operates in both cooling and heating mode, it performs the following: Figure 2 The full heating operation shown or Figure 3 The full cooling operation shown is the basic operation. Furthermore, the air conditioning unit 1 closes the high-pressure gas-side control valves 311, 321, and 331 among the multiple gas-side control valves 311, 312, 321, 322, 331, and 332 connected to the indoor units 201-203 that operate differently from the other indoor units, and opens the low-pressure gas-side control valves 312, 322, and 332. This reverses the refrigerant flow direction relative to the other indoor units 201-203. Therefore, the air conditioning unit 1 can operate a portion of the indoor units 201-203 in an operation opposite to the basic operation.

[0054] For example, Figure 4 The example shown is based on full heating operation, with only the third indoor unit 203 of the indoor units 201-203 operating in cooling mode. In this case, the air conditioning unit 1 closes the gas-side control valve 331 (corresponding to high-pressure and low-pressure gases) of the gas-side control valves 331 and 332 connected to the indoor heat exchanger 21 of the third indoor unit 203, and opens the gas-side control valve 332 (corresponding to low-pressure gases). As a result, the refrigerant dissipated in the indoor heat exchangers 21 of the indoor units 201 and 202 (other than the third indoor unit 203) flows into the indoor heat exchanger 21 of the third indoor unit 203, thus allowing only the indoor heat exchanger 21 of the third indoor unit 203 to function as an evaporator. Therefore, heating operation occurs in the first indoor unit 201 and the second indoor unit 202, while cooling operation occurs in the third indoor unit 203.

[0055] Furthermore, in mixed heating and cooling operation, whether to prioritize full heating operation or full cooling operation can be determined based on the proportion of heating or cooling operation relative to the overall operation. When the air conditioning unit 1 is in mixed heating and cooling operation, for example, if the proportion of heating operation relative to the overall operation is large, the basic operation can be set to full heating operation; if the proportion of cooling operation relative to the overall operation is large, the basic operation can be set to full cooling operation.

[0056] Next, refer to Figure 5 The electrical configuration of the air conditioning unit 1 will be described. The outdoor unit 10 also has an outdoor control unit 17. Each indoor unit 201 to 203 also has an indoor control unit 25. The outdoor control unit 17 and the indoor control unit 25 can be configured, for example, to include a computer, which has an arithmetic unit such as a CPU, a temporary storage medium such as RAM, and a non-temporary storage medium such as ROM and main storage device for storing the control program of the device.

[0057] The outdoor control unit 17 controls the overall operation of the air conditioning unit 1. The outdoor fan 12, outdoor expansion valve 13, compressor 14, first switching valve 15, and second switching valve 16 are electrically connected to the outdoor control unit 17. The outdoor control unit 17 controls the operation of the outdoor fan 12, outdoor expansion valve 13, compressor 14, first switching valve 15, and second switching valve 16.

[0058] The indoor control unit 25 of each indoor unit 201-203 is wirelessly connected to the outdoor control unit 17 via, for example, a wired or wireless communication device (not shown). Figure 5In this example, the outdoor control unit 17 is connected to the indoor control unit 25 of the indoor unit 201 via signal line 61, and the indoor control units 25 of indoor units 201-203 are connected to each other via signal lines 62. That is, the outdoor control unit 17 and the indoor control units 25 of indoor units 201-203 are connected in a chain, for example, via a so-called daisy-chain connection. Thus, the indoor control units 25 of each indoor unit 201-203 are communicatively electrically connected to the outdoor control unit 17. Furthermore, signal lines 251-253 extending from the indoor control units 25 of each indoor unit 201-203 are respectively connected to ports 51-53 of the terminal block 50 of the shut-off valve device 30. In this case, the ports 51-53 of the terminal block 50 are connected to... Figure 1 Each port of the shut-off valve device 30 corresponds to each liquid-side refrigerant pipe 461-463 and each gas-side refrigerant pipe 43-45.

[0059] In the following description, the port 51 corresponding to the first liquid-side refrigerant pipe 461 and the first gas-side refrigerant pipe 43 is sometimes referred to as the first port 51, the port 52 corresponding to the second liquid-side refrigerant pipe 462 and the second gas-side refrigerant pipe 44 is sometimes referred to as the second port 52, and the port 53 corresponding to the third liquid-side refrigerant pipe 463 and the third gas-side refrigerant pipe 45 is sometimes referred to as the third port 53. The outdoor control unit 17 can, for example, detect whether an indoor control unit 25 is connected to each port 51-53 via each indoor control unit 25. Furthermore, the outdoor control unit 17 can detect whether indoor units 201-203 are connected to each liquid-side refrigerant pipe 461-463 and each gas-side refrigerant pipe 43-45 based on whether an indoor control unit 25 is connected to each port 51-53.

[0060] The indoor air supply fan 22, indoor expansion valve 23, and leakage sensor 24 of each indoor unit 201-203 are electrically connected to the indoor control unit 25 of each indoor unit 201-203. Based on commands from the outdoor control unit 17, the indoor control unit 25 of each indoor unit 201-203 controls the operation of the indoor air supply fan 22, indoor expansion valve 23, and leakage sensor 24 of each indoor unit 201-203. Furthermore, the detection results of the leakage sensors 24 installed in each indoor unit 201-203 are transmitted to the outdoor control unit 17 via the indoor control unit 25 of each indoor unit 201-203.

[0061] The shut-off valve device 30 is electrically connected to the indoor control units 25 of each indoor unit 201-203, which are controlled by the shut-off valve device 30. Furthermore, the indoor control units 25 of each indoor unit 201-203 control the operation of the shut-off valve device 30 based on instructions from the outdoor control unit 17. Thus, in this embodiment, the outdoor control unit 17 acts as the central point, instructing all indoor units 201-203 and the shut-off valve device 30, and controlling the operation of each device.

[0062] In addition, such as Figure 5 As shown, the air conditioning unit 1 also includes a detection processing unit 171, a report processing unit 172, and a recycling processing unit 173. The detection processing unit 171, report processing unit 172, and recycling processing unit 173 can be implemented, for example, by executing a predetermined program using the CPU of the outdoor control unit 17. Furthermore, the detection processing unit 171, report processing unit 172, and recycling processing unit 173 can be implemented as a single hardware unit such as an integrated circuit with a predetermined program embedded in it, or some functions can be implemented using dedicated hardware, and some functions can be implemented through a combination of hardware and program. Moreover, the detection processing unit 171, report processing unit 172, and recycling processing unit 173 can also be implemented as an indoor control unit 25 instead of an outdoor control unit 17, or they can be implemented as functions distributed between the outdoor control unit 17 and the indoor control unit 25.

[0063] The detection processing unit 171 is capable of performing detection processing. This detection processing can be performed, for example, during assembly such as piping work in the air conditioning unit 1, but it can also be performed during normal operation of the air conditioning unit 1. The detection processing includes detecting a disconnected state where the first liquid-side refrigerant pipe 461 and the first gas-side refrigerant pipe 43, which are provided with the bypass passage 35, are not connected to the indoor unit 201. For example, if the detection processing unit 171 outputs a signal from the outdoor control unit 17 to the first port 51, and there is a response from the indoor control unit 25 to this signal, it is determined that the indoor control unit 25 is connected to the first port 51. In this case, the detection processing unit 171 detects the connection state where the indoor unit 201 is connected to the first liquid-side refrigerant pipe 461 and the first gas-side refrigerant pipe 43. Conversely, if there is no response from the indoor control unit 25 to the signal output from the outdoor control unit 17 to the first port 51, the detection processing unit 171 detects a disconnected state where the indoor control unit 25 is not connected to the first port 51.

[0064] The report processing unit 172 is capable of performing report processing. Report processing, like detection processing, is performed during piping work on the air conditioning unit 1, but can also be performed during normal operation of the air conditioning unit 1. In report processing, if the detection processing unit 171 detects that the first liquid-side refrigerant pipe 461 and the first gas-side refrigerant pipe 43, which are equipped with the bypass passage 35, are not connected, the report unit 18, etc., reports this disconnection to the operator. The report unit 18 may be, for example, a speaker or display unit installed on the outdoor unit 10 or each of the indoor units 201-203, or additionally, an external device connected via an electrical communication line, such as a maintenance company's server or a mobile terminal.

[0065] The recycling unit 173 is capable of performing recycling processes. For example... Figure 7 As shown, the recovery process includes operating the compressor 14 with the liquid-side control valve 34 closed to recover the refrigerant remaining in each indoor heat exchanger 21 back to the compressor 14 side. The recovery process unit 173 performs the recovery process when at least one of the leak sensors 24 installed in each of the plurality of indoor units 201 to 203 connected to the shut-off valve device 30 detects a refrigerant leak.

[0066] When performing refrigerant recovery, the recovery processing unit 173 first closes the liquid-side control valve 34, cutting off the refrigerant supply to the indoor heat exchangers 21 of all indoor units 201-203 of the air conditioning unit 1. Furthermore, the recovery processing unit 173 fully opens all valves 23, 311, 312, 321, 322, 331, and 332 of the control valves of the shut-off valve device 30 and the indoor units 201-203, except for the liquid-side control valve 34, or sets them to a state where the refrigerant can flow smoothly, thereby activating the compressor 14. At this time, the recovery processing unit 173 maintains the first switching valve 15 in a manner connecting the discharge side of the compressor 14 to the outdoor heat exchanger 11, and maintains the second switching valve 16 in a manner connecting the suction side of the compressor 14 to the indoor heat exchangers 21 of each indoor unit 201-203.

[0067] That is, the recycling unit 173 maintains the first switching valve 15 and the second switching valve 16 in a state consistent with... Figure 3The same procedure applies to full cooling operation. As a result, the refrigerant remaining in the indoor heat exchangers 21 of each indoor unit 201, 202, and 203 is recovered to the compressor 14 side. Therefore, refrigerant is removed from the indoor heat exchangers 21 of all indoor units 201-203, preventing further refrigerant leakage. Then, after recovering the refrigerant by running the compressor 14 for a certain period, the recovery processing unit 173 closes all the previously open gas-side control valves 311, 312, 321, 322, 331, and 332, and then stops the compressor 14 to complete the recovery process. Furthermore, regarding the indoor expansion valves 23 of each indoor unit 201-203, since the refrigerant flow has already been blocked by the upstream liquid-side control valve 34, it is not necessary to specifically close them.

[0068] As described above, the air conditioning unit 1 includes an outdoor unit 10, multiple indoor units 201-203, multiple liquid-side refrigerant lines 46, 461-463, multiple gas-side refrigerant lines 43-45, 431, 432, 441, 442, 451, 452, and a shut-off valve device 30. The outdoor unit 10 has an outdoor heat exchanger 11 and a compressor 14. Each indoor unit 201-203 has an indoor heat exchanger 21 connected to the outdoor heat exchanger 11 and the compressor 14.

[0069] Liquid-side refrigerant pipes 46, 461-463 connect the outdoor unit 10 to each indoor unit 201-203, functioning as multiple liquid refrigerant flow paths for liquid refrigerant. Gas-side refrigerant pipes 43-45, 431, 432, 441, 442, 451, 452 connect the outdoor unit 10 to each indoor unit 201-203, functioning as gaseous refrigerant flow paths for gaseous refrigerant. A shut-off valve device 30 is installed between the outdoor unit 10 and the multiple indoor units 201-203, and has the function of controlling the flow of refrigerant in the liquid-side refrigerant pipes 46, 461-463 and the gas-side refrigerant pipes 43-45, 431, 432, 441, 442, 451, 452.

[0070] Furthermore, the shut-off valve device 30 includes a liquid-side control valve 34 and gas-side control valves 311, 312, 321, 322, 331, and 332. The liquid-side control valve 34 is commonly provided on each of the liquid-side refrigerant lines 461-463, configured to shut off refrigerant flow relative to each of the liquid-side refrigerant lines 461-463. The gas-side control valves 311, 312, 321, 322, 331, and 332 are respectively provided on each of the gas-side refrigerant lines 43-45, configured to shut off refrigerant flow relative to each of the gas-side refrigerant lines 43-45.

[0071] Therefore, as described above, in the event of refrigerant leakage in each of the indoor units 201 to 203 of the air conditioning unit 1, the liquid side control valve 34 of the shut-off valve device 30 is closed to cut off the supply of refrigerant to each of the indoor units 201 to 203, and the refrigerant is recycled, thereby suppressing the expansion of refrigerant leakage.

[0072] On the other hand, in the event of a power outage when some or all of the indoor units 201-203 stop, the indoor expansion valve 23 becomes closed. Here, when the liquid-side control valve 34 and gas-side control valves 311, 312, 321, 322, 331, and 332 of the shut-off valve device 30 are closed by power supplied from the backup power supply 37, the refrigerant is sealed in a liquid-side refrigerant pipe 461-463 connecting the closed indoor expansion valve 23 and the liquid-side control valve 34, becoming liquid-sealed. Consequently, the pressure within the liquid-side refrigerant pipe 461-463 becomes liquid-sealed, increasing the risk of damage to the liquid-side refrigerant pipe 461-463 and refrigerant leakage.

[0073] Therefore, the shut-off valve device 30 also has a bypass passage 35 and a pressure relief valve 36. The bypass passage 35 connects the liquid-side refrigerant lines 46, 461-463 to the gas-side refrigerant lines 43-45, 431, 432, 441, 442, 451, 452 via the indoor units 201-203. Figure 1 In the example, the bypass 35 connects the liquid-side refrigerant pipe 461 to the gas-side refrigerant pipe 43 through the first indoor unit 201.

[0074] The pressure relief valve 36 is provided on the bypass passage 35. The pressure relief valve 36 is normally closed, but when the pressure exceeds a preset level, it is activated by the pressure and opens without the use of electricity to release the refrigerant pressure from the liquid-side refrigerant line 461 to the gas-side refrigerant line 43.

[0075] Therefore, even if the liquid-side control valve 34 and gas-side control valves 311, 312, 321, 322, 331, and 332 of the shut-off valve device 30 are closed when the indoor expansion valve 23 is closed, the pressure relief valve 36 will open when the pressure in the liquid-side refrigerant lines 461-463 rises to the operating pressure of the pressure relief valve 36. This releases the pressure in the liquid-side refrigerant lines 461-463 to the gas-side refrigerant line 43. Thus, it prevents the liquid-side refrigerant lines 461-463 from becoming liquid-sealed, and prevents damage to the liquid-side refrigerant lines 461-463 due to excessive refrigerant pressure.

[0076] However, when the pressure relief valve 36 experiences initial malfunction or foreign object intrusion, causing the liquid-side refrigerant pipe 461 to connect with the gas-side refrigerant pipe 43, refrigerant is allowed to flow back from the gas-side refrigerant pipe 43 to the liquid-side refrigerant pipe 461. In this case, if the bypass passage 35 is connected to the gas-side refrigerant pipes 431 and 432 on the outdoor unit 10 side of the gas-side control valves 311 and 312, the refrigerant recovered from each indoor unit 201-203 to the compressor 14 during the aforementioned recovery process may flow back into the first liquid-side refrigerant pipe 461 through the pressure relief valve 36. Furthermore, in this case, the amount of refrigerant flowing back into the pressure relief valve 36 may become close to the total amount in the refrigeration cycle.

[0077] Therefore, in this embodiment, the bypass 35 connects the liquid-side refrigerant pipes 46, 461-463 (to the side of the liquid-side control valve 34 near the indoor unit 201-203) to the gas-side refrigerant pipes 43-45, 431, 432, 441, 442, 451, 452 (to the side of the gas-side control valves 311, 312, 321, 322, 331, 332) near the indoor unit 201-203 in the gas-side refrigerant pipes 43-45, 431, 432, 441, 442, 451, 452. Figure 1 In the example, the bypass 35 connects the liquid-side refrigerant pipe 461 of the liquid-side control valve 34 on the indoor unit 201 side to the gas-side refrigerant pipe 43 of the gas-side control valves 311 and 312 on the indoor unit 201 side.

[0078] Therefore, even if the pressure relief valve 36 fails to operate normally due to initial malfunction or foreign object intrusion, the backflow of refrigerant recovered during the recovery process in the pressure relief valve 36 can be suppressed by closing the gas-side control valves 311 and 312. Thus, the air conditioning device 1 according to this embodiment can improve safety and reliability in the event of refrigerant leakage.

[0079] like Figure 6 As shown, the pressure relief valve 36 is positioned vertically above the connection portion 351 between the bypass passage 35 and the liquid-side refrigerant pipe 461, and the connection portion 352 between the bypass passage 35 and the gas-side refrigerant pipe 43. This prevents the accumulation of foreign matter such as cooling water and contaminants that may enter during the piping operation of the air conditioning unit 1 near the pressure relief valve 36. In other words, according to this configuration, even if a foreign object of a size large enough to cause malfunction of the pressure relief valve 36 is introduced into the refrigerant, it can be prevented from reaching the pressure relief valve 36, for example, by overcoming gravity. Therefore, malfunction of the pressure relief valve 36 due to foreign object intrusion can be prevented, resulting in further improved safety and reliability against refrigerant leaks.

[0080] Here, a pressure relief valve 36 is installed in the bypass passage 35 to prevent liquid sealing. However, if the refrigerant pipes 461 and 43 connected to the bypass passage 35 and the pressure relief valve 36 are not connected to the indoor unit 201, it would be the same as if the bypass passage 35 and the pressure relief valve 36 did not exist. In contrast, the inventors of this application have focused on the following: when performing piping work on the air conditioning unit 1, the operator connects each indoor unit 201 to 203 sequentially from the refrigerant pipe closest to the liquid side control valve 34. That is, when performing piping work on the air conditioning unit 1, the operator typically connects each indoor unit 201 to 203 in the following order: first liquid side refrigerant pipe 461 and first gas side refrigerant pipe 43, second liquid side refrigerant pipe 462 and second gas side refrigerant pipe 44, third liquid side refrigerant pipe 463 and third gas side refrigerant pipe 45.

[0081] Therefore, the bypass 35 is provided at the position where the refrigerant pipe closest to the liquid-side control valve 34 among the plurality of liquid-side refrigerant pipes 461-463 and the plurality of gas-side refrigerant pipes 43-45 is connected, in this case, the first liquid-side refrigerant pipe 461 and the first gas-side refrigerant pipe 43. This facilitates the connection of the first liquid-side refrigerant pipe 461 and the first gas-side refrigerant pipe 43, for which the bypass 35 is provided, to the indoor unit 201. Therefore, it is possible to suppress situations where the refrigerant pipes 461 and 43, connected to the bypass 35 and the pressure relief valve 36, are not connected to the indoor unit 201. As a result, the bypass 35 and the pressure relief valve 36 can function properly, thus further improving safety and reliability against refrigerant leakage.

[0082] Furthermore, the air conditioning unit 1 also includes a detection processing unit 171 and a report processing unit 172. The detection processing unit 171 detects a disconnection state where the refrigerant lines 461 and 43, which are equipped with the bypass passage 35, are not connected to the indoor unit 201. The report processing unit 172 reports the disconnection state detected by the detection processing unit 171. Therefore, when performing piping work on the air conditioning unit 1, the operator can more reliably know the disconnection state where the refrigerant lines 461 and 43, equipped with the bypass passage 35, are not connected to the indoor unit 201. This more reliably prevents situations where the refrigerant lines 461 and 43, which are connected to the bypass passage 35 and the pressure relief valve 36, are not connected to the indoor unit 201. As a result, the bypass passage 35 and the pressure relief valve 36 can function properly, thus further improving safety and reliability against refrigerant leaks.

[0083] Furthermore, the number of shut-off valve devices 30 installed in the air conditioning unit 1 is not limited to the above-mentioned number. For example, multiple shut-off valve devices 30 can be connected to form a refrigeration cycle. Moreover, the number of indoor units connected to the shut-off valve devices 30 is not limited to the above-mentioned number. As described above, the shut-off valve devices 30 can also be expanded from a model that can connect 2 indoor units to a model that can connect up to 8 indoor units, and even more.

[0084] Furthermore, the leakage sensor 24 does not need to be installed on all indoor units. For example, if multiple indoor units are installed in the same space, at least one leakage sensor 24 needs to be installed in one space.

[0085] In this embodiment, the outdoor control unit 17 performs various processes, such as refrigerant recovery when refrigerant leaks from the indoor unit of the air conditioning unit 1. However, any controller connected via a communication line and capable of sharing information can perform these processes, and its function can be assigned to any part. For example, if one of the control units of the indoor unit or the shut-off valve device 30 is set as the master unit, and the control units of other devices, including the outdoor control unit 17, are set as slave units, then by instructing the slave unit's control unit from the master unit, the same processes as described above can be performed. Furthermore, a centralized management device that manages the entire air conditioning unit 1 can be communicatively connected to the communication line between the indoor control unit 25 and the outdoor control unit 17, and this centralized management device can perform various processes when refrigerant leaks.

[0086] One embodiment of the invention has been described, but this embodiment is given by way of example and is not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, modifications, and combinations of components and controls can be made without departing from the spirit of the invention. These embodiments or variations thereof are included in the scope or spirit of the invention, and are included within the scope of the invention as described in the claims and its equivalents.

[0087] Explanation of reference numerals in the attached figures

[0088] 1…Air conditioning unit; 10…Outdoor unit; 11…Outdoor heat exchanger; 14…Compressor; 171…Detection and processing department; 172…Report processing department; 201, 202, 203…Indoor unit; 21…Indoor heat exchanger; 30…Shut-off valve device; 311, 312, 321, 322, 331, 332…Gas side control valve; 34…Liquid side control valve; 35…Bypass passage; 351, 352…Connection parts; 36…Pressure relief valve.

Claims

1. An air conditioning device, comprising: The outdoor unit includes an outdoor heat exchanger and a compressor; Multiple indoor units, each having an indoor heat exchanger connected to the outdoor heat exchanger and the compressor; Multiple liquid refrigerant flow paths and multiple gaseous refrigerant flow paths connect the outdoor unit to multiple indoor units. The multiple liquid refrigerant flow paths allow liquid refrigerant to pass through, and the multiple gaseous refrigerant flow paths allow gaseous refrigerant to pass through. as well as A shut-off valve device, installed between the outdoor unit and the multiple indoor units, is capable of controlling the flow of refrigerant in both the liquid refrigerant path and the gaseous refrigerant path. The shut-off valve device has: A liquid-side control valve is shared in multiple liquid refrigerant flow paths and is capable of cutting off the flow of refrigerant relative to the multiple liquid refrigerant flow paths; Gas-side control valves are respectively installed in multiple gas refrigerant flow paths, and are capable of cutting off the flow of refrigerant relative to the multiple gas refrigerant flow paths; A bypass passage connects the portion of the liquid refrigerant flow path closer to the indoor unit than the liquid-side control valve to the portion of the gaseous refrigerant flow path closer to the indoor unit than the gas-side control valve; and The pressure relief valve, located on the bypass passage, is normally closed. When the pressure exceeds a preset level, it operates without electricity to open, releasing the refrigerant pressure from the liquid refrigerant passage to the gaseous refrigerant passage.

2. The air conditioning device according to claim 1, wherein, The pressure relief valve is positioned vertically above the connection between the bypass passage and the liquid refrigerant flow path, and the connection between the bypass passage and the gaseous refrigerant flow path.

3. The air conditioning device according to claim 1, wherein, The bypass passage is located at the position that connects the liquid refrigerant passage and the gas refrigerant passage, which are closest to the liquid-side control valve among the plurality of liquid refrigerant passages and the plurality of gas refrigerant passages.

4. The air conditioning device according to any one of claims 1 to 3, wherein, It also has: The detection and processing unit detects a disconnected state where the indoor unit is not connected to the liquid refrigerant flow path and the gaseous refrigerant flow path, which are provided with the bypass passage; and The report processing unit reports when the detection processing unit detects the disconnected state.

5. The air conditioning device according to any one of claims 1 to 3, wherein, It also has: A backup power supply is provided to open the liquid-side control valve and the gas-side control valve in the event of a power outage.

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