Multi-type air conditioning unit

Abstract

This multi-type air-conditioning device is capable of simultaneously performing cooling and heating operations, and comprises: an outdoor unit; a plurality of indoor units each having an indoor heat exchanger and a leakage detection sensor; an SP device; and an MP device. The multi-type air-conditioning device comprises: a maintenance process unit that, when the leakage detection sensor provided in an indoor unit connected to the SP device detects leakage of a refrigerant, closes an SPL control valve and an SPG control valve corresponding to the indoor unit and stops the operation of the indoor unit, and maintains indoor units other than said indoor unit operable; and a recovery process unit that, when the leakage detection sensors provided in a plurality of indoor units connected to the MP device detect leakage of a refrigerant, operates a compressor in a state where an MPL control valve and an SPL control valve are closed to recover, to the compressor side, the refrigerant remaining in each of the indoor heat exchangers, and, after completion of the recovery of the refrigerant, closes all MPG control valves and SPG control valves and stops the compressor.

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a multi-type air conditioner. [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 conditioners. However, low-GWP refrigerants are generally flammable, including slightly flammable. Therefore, when using flammable refrigerants, it is necessary to ensure safety in the event of leakage from the equipment.

[0003] Therefore, in Europe, for example, safety measures are prescribed that are required depending on the amount of refrigerant sealed in the entire air conditioning system and the volume of the room in which the indoor unit is installed, etc. One safety measure is to install a leak detection sensor that detects refrigerant leakage in the indoor unit or in the room where the indoor unit is installed, and if a refrigerant leakage is detected, to cut off the supply of refrigerant to the indoor unit.

[0004] On the other hand, in so-called multi-type air conditioners in which multiple indoor units are connected in parallel in one refrigeration cycle, there is a demand for indoor units other than the one in which the refrigerant leak has occurred to continue operating. Therefore, for example, in a multi-type air conditioner, a configuration can be considered in which a shutoff valve device with a shutoff valve is provided in the refrigerant flow path of each indoor unit, and the shutoff valve is closed only in the indoor unit in which a refrigerant leak has been detected, allowing indoor units in which a refrigerant leak has not been detected to continue operating. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019 / 102517 Summary of the Invention [Problem to be solved by the invention]

[0006] One type of multi-type air conditioner described above is a so-called simultaneous cooling and heating multi-type air conditioner, which allows individual indoor units to select cooling operation or heating operation, i.e., allows a mixture of indoor units for cooling and indoor units for heating operation. In such a simultaneous cooling and heating multi-type air conditioner, the number of refrigerant pipes between the outdoor unit and the indoor units increases. This poses a problem of increasing the number of shut-off valves required for refrigerant control. Furthermore, because shut-off valve devices equipped with such shut-off valves are typically installed in the attic or elsewhere, increasing the number of shut-off valve devices necessitates securing installation space and significantly complicates installation work.

[0007] Therefore, the present invention provides a multi-type air conditioner capable of simultaneous heating and cooling operation, which can ensure safety and reliability against refrigerant leakage while minimizing the number of valves. [Means for solving the problem]

[0008] A multi-type air conditioner according to one embodiment is capable of simultaneous heating and cooling operation and includes an outdoor unit having 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 and a leak detection sensor capable of detecting refrigerant leakage, a single-port shutoff valve device capable of controlling the flow of refrigerant through one refrigerant flow passage to which the indoor unit is connected, and a multi-port shutoff valve device capable of controlling the flow of refrigerant through multiple refrigerant flow passages to which the multiple indoor units are connected. The single-port shutoff valve device includes a single-port liquid-side control valve provided in the refrigerant flow passage of the single-port shutoff valve device to control the flow of liquid refrigerant, and a single-port gas control valve provided in the refrigerant flow passage of the single-port shutoff valve device to control the flow of gaseous refrigerant. The multi-port shut-off valve device has a multi-port liquid-side control valve that is provided in common to the multiple indoor units in the multi-port shut-off valve device and controls the flow of liquid refrigerant, and a multi-port gas control valve that is provided in the refrigerant flow passage in the multi-port shut-off valve device and controls the flow of gaseous refrigerant. The multi-type air conditioner comprises a maintenance processing unit that, when the leak detection sensor provided in the indoor unit connected to the single-port shutoff valve device detects a refrigerant leak, is capable of performing a maintenance processing to close the single-port liquid-side control valve and the single-port gas control valve corresponding to the indoor unit to stop operation of the indoor unit and keep the indoor units other than the indoor unit operable; and a recovery processing unit that, when the leak detection sensor provided in a plurality of the indoor units connected to the multi-port shutoff valve device detects a refrigerant leak, is capable of performing a recovery processing to operate the compressor with the multi-port liquid-side control valve and the single-port liquid-side control valve closed to recover refrigerant remaining in each of the indoor heat exchangers to the compressor side, and after refrigerant recovery is completed, closes all of the multi-port gas control valves and the single-port gas control valves to stop the compressor. [Brief explanation of the drawings]

[0009] [Figure 1]Refrigeration cycle diagram of a multi-type air conditioner according to one embodiment [Figure 2] A refrigeration cycle diagram showing the flow of refrigerant when full heating operation is performed in the multi-type air conditioner. [Figure 3] A refrigeration cycle diagram showing the flow of refrigerant when full cooling operation is performed in the same multi-type air conditioner. [Figure 4] A refrigeration cycle diagram showing the flow of refrigerant when simultaneous cooling and heating operation is performed in the same multi-type air conditioner. [Figure 5] A block diagram showing the electrical configuration of the multi-type air conditioner. [Figure 6] A refrigeration cycle diagram showing the flow of refrigerant when recovery processing is performed in the same multi-type air conditioner. [Figure 7] FIG. 10 is a control flow diagram showing an example of control executed in the multi-type air conditioning device. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment will be described below with reference to the drawings. The air conditioner 1 shown in Figure 1 is a multi-type air conditioner that has multiple indoor units for one outdoor unit and is capable of all heating operation, all cooling operation, and simultaneous cooling and heating operation. All heating operation is an operating mode in which all indoor units perform heating operation. All cooling operation is an operating mode in which all indoor units perform cooling operation. Simultaneous cooling and heating operation is an operating mode in which some indoor units perform cooling operation and some indoor units perform heating operation. In the following explanation, all heating operation, all cooling operation, and simultaneous cooling and heating operation may be collectively referred to as air conditioning operation.

[0011] The air conditioner 1 is configured so that a single outdoor unit 10 can operate multiple indoor units 201, 202, 203, and 204. The air conditioner 1 includes, for example, one outdoor unit 10, multiple indoor units 201 to 204, a single-port shutoff valve device 30, and a multi-port shutoff valve device 40. The outdoor unit 10, the indoor units 201 to 204, the single-port shutoff valve device 30, and the multi-port shutoff valve device 40 configure a single refrigeration cycle that can circulate a refrigerant.

[0012] In this embodiment, "single-port" refers to a configuration in which the shutoff valve device has one pair of ports for connecting an indoor unit, i.e., one pair of refrigerant pipes serving as an inlet and an outlet. "Multi-port" refers to a configuration in which the shutoff valve device has multiple pairs of ports for connecting indoor units. In the following description, the single-port shutoff valve device 30 is sometimes referred to as the SP device 30, and the multi-port shutoff valve device 40 is sometimes referred to as the MP device 40. Here, the MP device 40 will be described as having three pairs of ports and being able to connect three indoor units. Note that the MP device 40 can be used in a variety of models, from a model with four pairs of ports and capable of connecting two indoor units to a model with up to 16 pairs of ports and capable of connecting eight indoor units. In other words, the MP device 40 is configured to connect two or more indoor units and be eight or less. Furthermore, in this embodiment, the refrigerant flow passage through which the refrigerant flows is composed of refrigerant pipes. The number of indoor units depends on the total rated capacity of the indoor units and the rated capacity of the outdoor unit, but generally, about 3 to 15 units can be connected to one outdoor unit 10.

[0013] The outdoor unit 10 is installed outdoors. As shown in the refrigeration cycle diagram of FIG. 1 , the outdoor unit 10 has an outdoor heat exchanger 11, an outdoor blower 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 has a function of exchanging heat between the refrigerant passing through the outdoor heat exchanger 11 and outside air. The outdoor blower 12 has a function of promoting heat exchange in the outdoor heat exchanger 11 by blowing air to the outdoor heat exchanger 11. A slightly flammable or flammable refrigerant is used as the refrigeration cycle refrigerant. In this embodiment, for example, the slightly flammable R32 is used as the refrigerant. In this embodiment, an example will be described in which four indoor units 201 to 204 are connected to the outdoor unit 10.

[0014] The outdoor expansion valve 13 is connected to a liquid-side refrigerant pipe 56 that runs from the outdoor unit 10 to the indoor units 201 to 204. The outdoor expansion valve 13 has the function of reducing the pressure of the refrigerant by adjusting the flow path width of the refrigerant passing through the outdoor expansion valve 13, and adjusting the flow rate and pressure of the refrigerant that flows out of the outdoor heat exchanger 11 or the refrigerant that flows into the outdoor heat exchanger 11. The outdoor expansion valve 13 can be configured as an electronic expansion valve that is driven by receiving an electrical signal from a computer (MCU: micro control unit) provided in the outdoor control unit 17 of the outdoor unit 10, for example, as shown in FIG. 5.

[0015] The first switching valve 15 and the second switching valve 16 have a 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 configured as, for example, four-way valves that are driven by receiving an electric signal, but multiple valves other than four-way valves may be combined as long as they can form the same refrigerant flow.

[0016] Compressor 14 compresses the refrigerant flowing through the refrigeration cycle and discharges the refrigerant, for example, in the direction indicated by the outline arrow in Fig. 1. Depending on the switching states of first switching valve 15 and second switching valve 16, compressor 14 either draws refrigerant on the outdoor heat exchanger 11 side as shown in Fig. 2 and discharges the drawn refrigerant toward the MP device 40 and SP device 30 side, or draws refrigerant on the MP device 40 and SP device 30 side as shown in Fig. 3 and discharges the drawn refrigerant toward the outdoor heat exchanger 11 side.

[0017] Each of the indoor units 201-204 is installed in a room that is the target of air conditioning operation. Each of the indoor units 201-204 has an indoor heat exchanger 21, an indoor blower 22, an indoor expansion valve 23, and a leak detection sensor 24. The indoor units 201-204 can basically have the same configuration, but the performance of the indoor heat exchanger 21, the indoor expansion valve 23, the indoor blower 22, and the leak detection sensor 24 can be changed as appropriate depending on the volume of the space in which they are installed. In the following description, when it is necessary to distinguish between the indoor units 201, 202, 203, and 204, they may be referred to as the first indoor unit 201, the second indoor unit 202, the third indoor unit 203, and the fourth indoor unit 204, respectively.

[0018] The indoor heat exchanger 21 exchanges heat between the refrigerant passing through the interior of the indoor heat exchanger 21 and the air in the room in which the indoor units 201 to 204 are installed. The indoor heat exchanger 21 is connected to the outdoor heat exchanger 11 and the compressor 14, and is configured to allow the refrigerant to circulate between the outdoor heat exchanger 11, the indoor heat exchanger 21, and the compressor 14. The indoor blower 22 blows air to the indoor heat exchanger 21, thereby promoting heat exchange in the indoor heat exchanger 21 and supplying air whose temperature has been adjusted by the indoor heat exchanger 21 into the room.

[0019] The indoor expansion valve 23 has the function of adjusting the flow path width of the refrigerant passing through the indoor expansion valve 23 and controlling the amount of refrigerant circulating. Similar to the outdoor expansion valve 13, the indoor expansion valve 23 can be configured as an electronic expansion valve that is driven by receiving an electric signal from a computer provided in the indoor control unit 25 of each of the indoor units 201-204, for example.

[0020] As shown in Fig. 5, each of the indoor units 201-204 has an indoor control unit 25. Furthermore, although details are not shown, the SP device 30 and the MP device 40 also have control units configured with a computer. The outdoor control unit 17 of the outdoor unit 10, the indoor control units 25 of each of the indoor units 201-204, and the control units (not shown) of the SP device 30 and the MP device 40 are mutually connected by communication lines, and exchange various types of information.

[0021] The leak detection sensor 24 has the function of detecting refrigerant leakage in each of the indoor units 201, 202, 203, and 204. The leak detection sensor 24 may be incorporated into each of the indoor units 201-204, or may be installed independently as a leak detection sensor unit in the indoor space of each of the rooms in which the indoor units 201-204 are installed. In this embodiment, a leak detection sensor 24 is provided in each of the indoor units 201-204. The leak detection sensor 24 may be configured, for example, as a semiconductor gas sensor. The leak detection sensor 24 is capable of detecting the refrigerant sealed in the refrigeration cycle, in this case, R32. The leak detection sensor 24 outputs an electrical signal that changes linearly depending on the refrigerant concentration, for example, for refrigerant concentrations of approximately 300 to 30,000 ppm in the air. If the detected concentration exceeds a predetermined value, the leak detection sensor 24 notifies the corresponding indoor unit 201-204 and outdoor unit 10 that a refrigerant leak has occurred.

[0022] The SP device 30 is configured to be able to control the flow of refrigerant to one indoor unit 204, in this case, for example, the fourth indoor unit 204. The indoor heat exchanger 21 of the fourth indoor unit 204 is connected to the SP device 30. The SP device 30 is provided between the outdoor unit 10 and the fourth indoor unit 204. In other words, the outdoor unit 10 and the fourth indoor unit 204 are connected via the SP device 30. The SP device 30 has one single-port liquid-side control valve 31, two single-port gas control valves 321, 322, and a pressure relief valve 33. Hereinafter, the single-port liquid-side control valve 31 may be referred to as the SPL control valve 31, and the single-port gas control valves 321, 322 may be referred to as the SPG control valves 321, 322.

[0023] The SPL control valve 31 is provided between liquid side refrigerant pipes 511, 512 that connect the outdoor heat exchanger 11 and the indoor heat exchanger 21 of the fourth indoor unit 204, and has the function of controlling the flow of liquid refrigerant. The liquid side refrigerant pipe 51 is a liquid side refrigerant flow passage that branches off from the liquid side refrigerant pipe 56 connected to the outdoor unit 10, and passes liquid refrigerant. One end of the liquid side refrigerant pipe 511 is connected to the liquid side refrigerant pipe 51 via the SPL control valve 31, and the other end is connected to the indoor heat exchanger 21, and serves as a flow passage that flows liquid refrigerant to the indoor heat exchanger 21 of the fourth indoor unit 204.

[0024] The SPL control valve 31 can be configured as, for example, an electronically controlled valve that is driven by receiving an electric signal. The SPL control valve 31 can adjust the opening of the SPL control valve 31, i.e., the flow rate of the refrigerant flowing through the liquid-side refrigerant pipe 51, in response to an electric signal from the control unit of the SP device 30. The SPL control valve 31 also functions as an on-off valve that completely shuts off the flow of refrigerant through the liquid-side refrigerant pipe 51.

[0025] The SPG control valves 321, 322 are provided on the paths of the gas side refrigerant pipes 52, 521, 522, respectively, and have the function of controlling the flow of gaseous refrigerant. The gas side refrigerant pipes 52, 521, 522 are refrigerant flow passages that connect the indoor heat exchanger 21 of the fourth indoor unit 204 and the compressor 14, and allow gaseous refrigerant to pass through. The gas side refrigerant pipes 521, 522 merge midway to form a single gas side refrigerant pipe 52, which is connected to the indoor heat exchanger 21 of the fourth indoor unit 204. In this case, the liquid side refrigerant pipe 511 and the gas side refrigerant pipe 52 connected to the fourth indoor unit 204 constitute a single refrigerant flow passage to which the fourth indoor unit 204 is connected.

[0026] The SPG control valves 321, 322 can be configured as so-called electronically controllable electronic control valves that are driven by receiving, for example, an electrical signal, and can adjust the opening of the SPG control valves 321, 322, i.e., the flow rate of refrigerant flowing through the gas side refrigerant pipes 521, 522, based on an electrical signal from the control unit of the SP device 30. For example, one of the two SPG control valves 321, 322 is compatible with both high-pressure gas and low-pressure gas, and the other is compatible with only low-pressure gas. In this embodiment, the SPG control valve 321 is compatible with both high-pressure gas and low-pressure gas, and the SPG control valve 322 is compatible with only low-pressure gas. By closing both of the two SPG control valves 321, 322, the air conditioning apparatus 1 can block the refrigerant flowing between the indoor heat exchanger 21 and the compressor 14 of the fourth indoor unit 204, i.e., the refrigerant flowing through the gas side refrigerant pipes 52, 521, 522.

[0027] The pressure relief valve 33 connects the liquid side refrigerant pipe 51 and the gas side refrigerant pipe 52. The pressure relief valve 33 has the function of releasing part of the pressure to the gas side refrigerant pipe 52 when the liquid side refrigerant pipe 51 becomes excessively high pressure due to a liquid seal or the like.

[0028] The MP device 40 is installed between the outdoor unit 10 and the first indoor unit 201, second indoor unit 202, and third indoor unit 203. That is, the outdoor unit 10 and the first indoor unit 201, second indoor unit 202, and third indoor unit 203 are connected via the MP device 40. The MP device 40 has multiple gas control valve units (three in this case) 41, 42, and 43 corresponding to the multiple indoor units 201 to 203 connected to the MP device 40, and one multi-port liquid-side control valve 44. In the following description, when distinguishing between the gas control valve units 41, 42, and 43, they may be referred to as the first gas control valve unit 41, the second gas control valve unit 42, and the third gas control valve unit 43, respectively. Furthermore, the multi-port liquid-side control valve 44 may be referred to as the MPL control valve 44.

[0029] Each of the gas control valve units 41 to 43 has two of the multiport gas control valves 411, 412, 421, 422, 431, and 432. Hereinafter, the multiport gas control valves 411, 412, 421, 422, 431, and 432 will also be referred to as MPG control valves 411, 412, 421, 422, 431, and 432. The MPG control valves 411, 412, 421, 422, 431, and 432 are provided on the paths of the gas side refrigerant pipes 531, 532, 541, 542, 551, and 552, respectively, and have the function of controlling the flow of gaseous refrigerant.

[0030] Gas side refrigerant pipes 531, 532, 541, 542, 551, 552 are part of the refrigerant flow passage connecting the indoor heat exchangers 21 and the compressors 14 of the first indoor unit 201, second indoor unit 202, and third indoor unit 203, and pass gaseous refrigerant. The gas side refrigerant pipes 531, 532, 541, 542, 551, 552 join together to form gas side refrigerant pipes 53, 54, 55, which are connected to the indoor heat exchangers 21 of the indoor units 201, 202, 203. In this case, liquid side refrigerant pipes 561-563 and gas side refrigerant pipes 53-55 connected to the indoor units 201-203 constitute the refrigerant flow passage to which the indoor units 201-203 are connected, respectively.

[0031] Like the SPG control valves 321 and 322, the MPG control valves 411, 412, 421, 422, 431 and 432 can be configured as so-called electronically controlled valves that are driven by receiving an electrical signal, and their opening, i.e., the flow rate of the refrigerant flowing through the corresponding gas side refrigerant pipes 531, 532, 541, 542, 551 and 552, can be adjusted in accordance with an electrical signal input from the control unit of the MP device 40.

[0032] In each gas control valve unit 41, 42, 43, one of the two MPG control valves 411, 412, 421, 422, 431, 432 is compatible with both high-pressure gas and low-pressure gas, and the other is compatible with only low-pressure gas. In this embodiment, for example, the MPG control valves 411, 421, 431 are compatible with both high-pressure gas and low-pressure gas, and the MPG control valves 412, 422, 432 are compatible with only low-pressure gas. By closing the MPG control valves 411, 412, 421, 422, 431, 432 of each gas control valve unit 41, 42, 43, the air conditioner 1 can block the refrigerant flowing between the indoor heat exchanger 21 and the compressor 14 of each indoor unit 201-203, i.e., the refrigerant flowing through the gas-side refrigerant pipes 531, 532, 541, 542, 551, 552.

[0033] The MPL control valve 44 is provided midway along the liquid-side refrigerant pipe 56 that connects the outdoor heat exchanger 11 and the indoor heat exchangers 21 of each of the indoor units 201-203, and has the function of controlling the flow of liquid refrigerant. The liquid-side refrigerant pipe 56 is a refrigerant flow passage that connects the outdoor heat exchanger 11 and the indoor heat exchangers 21 of each of the indoor units 201-203, and passes liquid refrigerant. The liquid-side refrigerant pipe 56 branches into liquid-side refrigerant pipes 561-563 on the indoor unit 201-203 side relative to the MPL control valve 44, and each of these is connected to one end of the indoor heat exchanger 21 of each of the indoor units 201-203.

[0034] In this embodiment, the MP device 40 will be described using an example in which three indoor units 201-203 can be connected, but there are also models or types in which two or four or more indoor units can be connected. In all models, only one MPL control valve 44 is provided in the liquid side refrigerant pipe 56. This configuration simplifies the refrigerant circuit and piping layout. Note that the number of MPG control valves 411, 412, 421, 422, 431, 432 required is twice the number of indoor units 201-203 to be connected.

[0035] The MPL control valve 44 can be configured as, for example, an electronically controlled valve that is driven by receiving an electrical signal, and can be electronically controlled. Based on electrical control from the control unit of the MP device 40, the MPL control valve 44 can adjust its opening, i.e., the flow rate of the refrigerant flowing through the liquid-side refrigerant pipe 51, and has the function of completely blocking the flow of refrigerant through the liquid-side refrigerant pipe 56.

[0036] One of the multiple gas control valve units 41 to 43 has a pressure relief valve 413. In the present embodiment, the first gas control valve unit 41 has the pressure relief valve 413. The pressure relief valve 413 connects the liquid side refrigerant pipe 561 and the gas side refrigerant pipe 53. The pressure relief valve 413 has the function of releasing part of the pressure to the gas side refrigerant pipe 53 when the liquid side refrigerant pipe 561 side becomes liquid-sealed and becomes excessively high pressure.

[0037] 2 to 4 and 6, the thick black solid lines and white arrows in the refrigerant flow paths are intended to illustrate the main flow of refrigerant during each operation, and may differ from the actual refrigerant flow. That is, in reality, refrigerant may fill areas not indicated by the thick black solid lines.

[0038] When the air conditioner 1 performs heating only operation, as shown in Fig. 2, the first selector valve 15 is switched to a mode that connects the suction side of the compressor 14 to the outdoor heat exchanger 11, and the second selector valve 16 is switched to a mode that connects the discharge side of the compressor 14 to the indoor heat exchangers 21 of each of the indoor units 201 to 204. In heating only operation, the outdoor heat exchanger 11 functions as an evaporator, and the indoor heat exchangers 21 of all of the indoor units 201 to 204 function as condensers.

[0039] In this case, in the SP device 30, the air conditioner 1 closes the SPG control valve 322 that corresponds to only low-pressure gas, and opens the SPG control valve 321 that corresponds to both high-pressure gas and low-pressure gas. In addition, in the MP device 40, the air conditioner 1 closes the MPG control valves 412, 422, and 432 that correspond to only low-pressure gas, and opens the MPG control valves 411, 421, and 431 that correspond to both high-pressure gas and low-pressure gas. Then, each of the indoor units 201-204 adjusts the heating output of the indoor units 201-204 by controlling the opening degree of its own indoor expansion valve 23.

[0040] When the air conditioner 1 performs cooling only operation, as shown in Fig. 3, the first switching valve 15 is switched to a mode that connects the discharge side of the compressor 14 to the outdoor heat exchanger 11, and the second switching valve 16 is switched to a mode that connects the suction side of the compressor 14 to the indoor heat exchangers 21 of each of the indoor units 201 to 204. In cooling only operation, the outdoor heat exchanger 11 functions as a condenser, and the indoor heat exchangers 21 of all of the indoor units 201 to 204 function as evaporators.

[0041] In this case, with regard to the SP device 30, the air conditioner 1 closes the SPG control valve 322 corresponding to only low-pressure gas, and opens the SPG control valve 321 corresponding to high-pressure gas and low-pressure gas, just as in heating only operation. Also, with regard to the MP device 40, the air conditioner 1 closes the MPG control valves 412, 422, and 432 corresponding to only low-pressure gas, and opens the MPG control valves 411, 421, and 431 corresponding to high-pressure gas and low-pressure gas. Then, each of the indoor units 201-204 adjusts the cooling output of the indoor units 201-204 by controlling the opening degree of its own indoor expansion valve 23.

[0042] When simultaneous heating and cooling operation is performed, the air conditioner 1 performs a basic operation, either the all-heating operation shown in Fig. 2 or the all-cooling operation shown in Fig. 3. Of the multiple gas refrigerant control valves 321, 322, 411, 412, 421, 422, 431, 432 connected to the indoor units 201-204 performing a different operation from the others, the air conditioner 1 closes the MPG control valves 411, 421, 431 corresponding to high-pressure and low-pressure gas and opens the MPG control valve 412, 422, 432 corresponding only to low-pressure gas, thereby causing the refrigerant flow direction for the indoor units 201-204 performing a different operation to be opposite to that of the other indoor units 201-204. This allows the air conditioner 1 to perform an operation opposite to the basic operation for some of the indoor units 201-204.

[0043] For example, the example shown in Fig. 4 is a mode in which all heating operation is the basis, and only the third indoor unit 203 of the indoor units 201-204 performs cooling operation. In this case, the air conditioner 1 closes the MPG control valve 431 corresponding to the high-pressure and low-pressure gases out of the MPG control valves 431, 432 connected to the indoor heat exchanger 21 of the third indoor unit 203, and opens the MPG control valve 432 corresponding to the low-pressure gas. Then, the refrigerant that has dissipated heat in the indoor heat exchangers 21 of the indoor units 201, 202, and 204 other than the third indoor unit 203 flows into the indoor heat exchanger 21 of the third indoor unit 203, and only the indoor heat exchanger 21 of the third indoor unit 203 functions as an evaporator. As a result, the first indoor unit 201, the second indoor unit 202, and the fourth indoor unit 204 perform heating operation, and the third indoor unit 203 performs cooling operation.

[0044] In addition, whether to use full heating operation or full cooling operation as the basis in the cooling and heating mixed operation can be determined depending on the proportion of heating operation or cooling operation to the whole. When performing cooling and heating mixed operation, the air conditioner 1 can, for example, set the basic operation to full heating operation if the proportion of heating operation to the whole is large, and can set the basic operation to full cooling operation if the proportion of cooling operation to the whole is large.

[0045] Next, the electrical configuration of the air conditioning apparatus 1 will be described with reference to Fig. 5. The outdoor unit 10 further has an outdoor control unit 17. Each of the indoor units 201 to 204 further has an indoor control unit 25. The outdoor control unit 17 and the indoor control unit 25 can be configured to include a computer or the like having, for example, an arithmetic unit such as a CPU, a temporary storage medium such as RAM, and a non-temporary storage medium such as a ROM or main memory device that stores a control program for the device.

[0046] The outdoor control unit 17 controls the operation of the entire air conditioning apparatus 1. The outdoor blower 12, the outdoor expansion valve 13, the compressor 14, the first switching valve 15, and the second switching valve 16 are electrically connected to the outdoor control unit 17. The outdoor control unit 17 controls the operation of the outdoor blower 12, the outdoor expansion valve 13, the compressor 14, the first switching valve 15, and the second switching valve 16.

[0047] The indoor control unit 25 of each of the indoor units 201-204 is electrically connected to the outdoor control unit 17 so as to be able to communicate with the indoor control unit 17. The indoor blower 22, indoor expansion valve 23, and leak detection sensor 24 of each of the indoor units 201-204 are electrically connected to the indoor control unit 25 of each of the indoor units 201-204. The indoor control unit 25 of each of the indoor units 201-204 controls the operation of the indoor blower 22, indoor expansion valve 23, and leak detection sensor 24 of each of the indoor units 201-204 based on commands from the outdoor control unit 17. Furthermore, the detection results of the leak detection sensor 24 provided in each of the indoor units 201-204 are transmitted to the outdoor control unit 17 via the indoor control unit 25 of each of the indoor units 201-204.

[0048] The SP device 30 and the MP device 40 operate upon receiving commands from the outdoor control unit 17 via the indoor control unit 25. For example, the SP device 30 is electrically connected to, and able to communicate with, the indoor control unit 25 of the fourth indoor unit 204, which is the control target of the SP device 30. In this case, the indoor control unit 25 of the fourth indoor unit 204 controls the operation of the SP device 30 based on commands from the outdoor control unit 17. The MP device 40 is electrically connected to the indoor control unit 25 of one of the indoor units 201 to 203, which are the control targets of the MP device 40. In this embodiment, the MP device 40 is electrically connected to the indoor control unit 25 of the first indoor unit 201. The indoor control unit 25 of the first indoor unit 201 controls the operation of the MP device 40 based on commands from the outdoor control unit 17. Note that the SP device 30 and the MP device 40 may also be configured to operate upon receiving commands directly from the outdoor control unit 17 without going through the indoor control unit 25. In this embodiment, the outdoor control unit 17 plays a central role in issuing instructions to all of the indoor units 201 to 204, the SP device 30, and the MP device 40, thereby controlling the operation of each device.

[0049] 5, the air conditioning apparatus 1 further includes a maintenance processing unit 171, a collection processing unit 172, a total stop processing unit 173, a setting processing unit 174, a first notification processing unit 175, and a second notification processing unit 176. The maintenance processing unit 171, the collection processing unit 172, the total stop processing unit 173, the setting processing unit 174, the first notification processing unit 175, and the second notification processing unit 176 may be realized, for example, by executing a predetermined program on a CPU included in the outdoor control unit 17. The maintenance processing unit 171, the collection processing unit 172, the total stop processing unit 173, the setting processing unit 174, the first notification processing unit 175, and the second notification processing unit 176 may be realized by standalone hardware such as an integrated circuit that implements a predetermined program, or some functions may be realized by dedicated hardware and some functions may be realized by a combination of hardware and a program. Furthermore, the maintenance processing unit 171, recovery processing unit 172, total stop processing unit 173, setting processing unit 174, first notification processing unit 175, and second notification processing unit 176 may be realized as functions of the indoor control unit 25 rather than the outdoor control unit 17, or may be realized as functions distributed between the outdoor control unit 17 and the indoor control unit 25.

[0050] When the leakage detection sensor 24 provided in an indoor unit connected to the SP device 30, in this case the fourth indoor unit 204, detects a refrigerant leakage, the maintenance processing unit 171 closes at least the SPL control valve 31 and the SPG control valves 321, 322 located in the refrigerant flow passage of the indoor unit 204 to isolate the indoor unit 204 from the refrigeration cycle, i.e., the refrigerant flow passage, to prevent leakage of more than the amount of refrigerant present inside the indoor unit 204, stopping operation of the fourth indoor unit 204, and can execute maintenance processing to keep the indoor units 201-203 other than the indoor unit 204 operable. The maintenance processing is executable only when a refrigerant leakage occurs in an indoor unit connected to the SP device 30, and is not executed when a refrigerant leakage occurs in any of the indoor units 201-203 connected to the MP device 40.

[0051] When the outdoor control unit 17 has performed the maintenance process, it may be configured to notify the user, a maintenance company, or the like that a refrigerant leak has occurred, for example, by using a speaker or display unit (not shown) connected to the outdoor control unit 17, or by using an external device connected via a telecommunications line. When the outdoor control unit 17 has performed the maintenance process, it accepts an operation from the user to run the air conditioning for the indoor units 201 to 203 other than the indoor unit 204 in which the refrigerant leak has occurred, just as if the indoor units were in a normal state.

[0052] The recovery processing unit 172 is capable of executing the recovery processing. As shown in Fig. 6, the recovery processing includes a process of operating the compressor 14 with the MPL control valve 44 and the SPL control valve 31 closed and recovering the refrigerant remaining in each indoor heat exchanger 21 to the compressor 14 side. The recovery processing unit 172 executes the recovery processing when at least one of the leak detection sensors 24 provided in each of the multiple indoor units 201 to 203 connected to the MP device 40 detects a refrigerant leak. Furthermore, when the leak detection sensor 24 provided in the indoor unit 204 connected to the SP device 30 detects a refrigerant leak and the recovery processing is set in the setting processing described below, the recovery processing is executed.

[0053] The recovery process is executed when a refrigerant leak occurs in the indoor units 201-203 connected to the MP device 40, or when a refrigerant leak occurs in the indoor unit 204 connected to the SP device 30 and the recovery process is set to be executed with priority over the maintenance process. When the recovery process is executed, the recovery processing unit 172 first closes the SPL control valve 31 and the MPL control valve 44 to cut off the supply of refrigerant to the indoor heat exchangers 21 of all of the indoor units 201-204 included in the air conditioner 1.

[0054] Furthermore, the recovery processing unit 172 operates the compressor 14 with all valves 23, 411, 412, 421, 422, 431, 432, 321, 322 of the MP device 40, the SP device 30, and the indoor units 201-204, other than the MPL control valve 44 and the SPL control valve 31, fully open or in a state with a large opening that allows smooth refrigerant flow. At this time, the recovery processing unit 172 maintains the first switching valve 15 in a state that connects the discharge side of the compressor 14 to the outdoor heat exchanger 11, and maintains the second switching valve 16 in a state that connects the suction side of the compressor 14 to the indoor heat exchangers 21 of each of the indoor units 201-204.

[0055] That is, the recovery processing unit 172 maintains the first switching valve 15 and the second switching valve 16 in the same mode as in the cooling only operation shown in Fig. 3. As a result, the refrigerant remaining in the indoor heat exchangers 21 of the indoor units 201, 202, 203, and 204 is recovered to the compressor 14 side. Therefore, the refrigerant is removed from the indoor heat exchangers 21 of all of the indoor units 201 to 204, preventing further leakage of the refrigerant. Then, the recovery processing unit 172 operates the compressor 14 for a certain period of time to recover the refrigerant, and then fully closes the MPG control valves 411, 412, 421, 422, 431, and 432 and the SPG control valves 321 and 322 that were open, and then stops the compressor 14 to complete the recovery processing. It should be noted that there is no particular need to close the indoor expansion valves 23 of the indoor units 201 to 204, since the SPL control valve 31 and MPL control valve 44 located upstream thereof have already blocked the flow of refrigerant.

[0056] The all-stop processing unit 173 is a process executed after the recovery process is completed, and prohibits the operation of the compressor 14 of the outdoor unit 10, all indoor units 201-204, SP device 30, and MP device 40 thereafter.

[0057] Then, by executing the total stop processing, the outdoor control unit 17 will reject any subsequent user instructions to operate the air conditioning that are issued from all of the indoor units 201 to 204. After that, for example, a maintenance service technician can repair the leak and return the system to normal, and then cancel the total stop processing using a special operation, allowing the operation of the air conditioner 1 to resume.

[0058] The setting processing unit 174 is capable of executing setting processing. The setting processing is processing for setting in advance, that is, prior to operation of the air conditioner 1, whether maintenance processing or recovery processing will be performed when the leak detection sensor 24 provided in the indoor units 201-203 connected to the SP device 30 detects a refrigerant leak, based on input from a user, i.e., a manager of the air conditioner 1, etc. This setting can be input using, for example, an input device provided directly in the outdoor control unit 17, or a personal computer or mobile terminal indirectly connected via a telecommunications line, etc.

[0059] Furthermore, when the leak detection sensor 24 detects a refrigerant leak, the outdoor control unit 17 uses a notification unit 177 connected to the outdoor control unit 17 shown in Fig. 5 to notify the user, a maintenance company, etc. that a refrigerant leak has occurred. The notification unit 177 is, for example, a speaker or a display unit provided in the outdoor unit 10 or each of the indoor units 201-204, and may additionally be an external device connected via a telecommunications line, such as a server or mobile terminal of the maintenance company.

[0060] The air conditioner 1 provides different notification content when a refrigerant leak is detected in the indoor unit 204 connected to the SP device 30, and when a refrigerant leak is detected in one of the indoor units 201 to 203 connected to the MP device 40. In this case, the air conditioner 1 notifies the user of the cause of the abnormality so that the user can distinguish between abnormal conditions, thereby preventing confusion for the user.

[0061] The air conditioning apparatus 1 is equipped with a first notification processor 175 and a second notification processor 176 as processing units for executing the above-mentioned notification. The first notification processor 175 executes the first notification process when maintenance processing is executed. The first notification process is a process of notifying a user, a maintenance company, etc. using the notification unit 177, etc., that the indoor unit from which the refrigerant leaked cannot operate but that indoor units other than the one from which the refrigerant leaked can continue to operate. In other words, the notification content in the first notification process includes information that an abnormality has occurred in the air conditioning apparatus 1 but that the indoor units 201-203 connected to the MP device 40 can continue to operate. The second notification processor 176 executes the second notification process when all-stop processing is executed. The second notification process is a process of notifying a user, a maintenance company, etc., using the notification unit 177, etc., that operation of all indoor units 201-204 is impossible.

[0062] Next, the control flow when a refrigerant leak occurs in any of the indoor units 201 to 204 will be described with reference to Fig. 7. In the following description, it is assumed that the processing in the maintenance processing unit 171, recovery processing unit 172, total stop processing unit 173, setting processing unit 174, first notification processing unit 175, and second notification processing unit 176 is all executed mainly by the outdoor control unit 17. It is also assumed that the setting processing by the setting processing unit 174 is executed prior to air conditioning operation.

[0063] The outdoor control unit 17 constantly monitors for refrigerant leakage in each of the indoor units 201-204 based on the output of the leakage detection sensor 24 in each of the indoor units 201-204 via the indoor control unit 25 of each of the indoor units 201-204 while the air conditioner 1 is in operation. If no refrigerant leakage is detected in any of the indoor units 201-204 (NO in step S11), the outdoor control unit 17 repeats step S11. On the other hand, if a refrigerant leakage is detected in at least one of the indoor units 201-204 (YES in step S11), the outdoor control unit 17 proceeds to step S12.

[0064] In step S12, the outdoor control unit 17 determines in which of the indoor units 201-204 a refrigerant leak has been detected. That is, in step S12, the outdoor control unit 17 determines whether the indoor unit 201-204 in which a refrigerant leak has been detected is connected to the SP device 30 or the MP device 40.

[0065] If the indoor unit 201-204 in which a refrigerant leak has been detected is connected to the SP device 30 (SP device in step S12), that is, if it is the fourth indoor unit 204, the outdoor control unit 17 shifts the process to step S13. In step S13, the outdoor control unit 17 determines whether the setting content in the setting process is "maintenance process" or "recovery process". If it is set to "maintenance process", the outdoor control unit 17 shifts the process to step S14.

[0066] The outdoor control unit 17 then executes the maintenance process described above in step S14, stops operation of the indoor unit 204 connected to the SP device 30, closes the SPL control valve 31 and the SPG control valves 321 and 322 in the SP device 30 to isolate the indoor unit 204 from the refrigerant path, and maintains the indoor units 201-203 other than the indoor unit 204 in operable condition. Next, the outdoor control unit 17 executes a first notification process in step S15 to notify the user or the like that an abnormality in the air conditioner 1 has occurred, causing a refrigerant leak, and that the indoor unit 204 with the refrigerant leak cannot operate, but the other indoor units 201-203 can continue to operate. The outdoor control unit 17 then returns the process to step S11 and executes step S11 and subsequent steps again.

[0067] If the indoor unit 201-204 in which a refrigerant leak has been detected is connected to the MP device 40 (MP device in step S12), that is, if it is any of the first indoor unit 201, second indoor unit 202, or third indoor unit 203, the outdoor control unit 17 shifts the process to step S15. Also, if a refrigerant leak has been detected in the indoor unit 204 connected to the SP device 40 ("SP device" in step S12) and the setting content in the setting process has been set to "recovery process" ("recovery process" in step S13), the outdoor control unit 17 shifts the process to step S15.

[0068] The outdoor control unit 17 executes the recovery process described above in step S15, and recovers the refrigerant remaining in the indoor heat exchangers 21 of each of the indoor units 201-204 to the compressor 14 side. Thereafter, the outdoor control unit 17 executes the all-stop process described above in step S16, and prohibits restarting of each of the indoor units 201-204. Next, the outdoor control unit 17 executes the second notification process in step S17, and notifies that operation is impossible for all of the indoor units 201-204. Then, the outdoor control unit 17 ends the series of processes (END).

[0069] According to the embodiment described above, the multi-type air conditioner 1 is capable of simultaneous heating and cooling operation and includes an outdoor unit 10, multiple indoor units 201-204, a SP device 30, and an MP device 40. The outdoor unit 10 has an outdoor heat exchanger 11 and a compressor 14. The indoor units 201-204 have an indoor heat exchanger 21 connected to the outdoor heat exchanger 11 and the compressor 14, and a leak detection sensor 24 capable of detecting refrigerant leakage. The SP device 30 is configured to be able to control the flow of refrigerant through a liquid-side refrigerant pipe 511 and a gas-side refrigerant pipe 52, which form a single refrigerant flow path to which the indoor unit 204 is connected. The MP device 40 is configured to be able to control the flow of refrigerant through liquid-side refrigerant pipes 561-563 and gas-side refrigerant pipes 53-55, which form a plurality of refrigerant flow paths to which the multiple indoor units 201-203 are connected.

[0070] The SP device 30 has an SPL control valve 31 and SPG control valves 321, 322. The SPL control valve 31 is provided in a liquid-side refrigerant pipe 511, which is a refrigerant flow path in the SP device 30, and has the function of controlling the flow of liquid refrigerant. That is, one SPL control valve 31 is provided for each indoor heat exchanger 21. The SPG control valves 321, 322 are provided in a gas-side refrigerant pipe 52, which is a refrigerant flow path in the SP device 30, and have the function of controlling the flow of gaseous refrigerant.

[0071] The MP device 40 has an MPL control valve 44 and MPG control valves 411, 412, 421, 422, 431, and 432. The MPL control valve 44 is provided in common to multiple indoor units 201, 202, and 203 in the MP device 40, and has the function of controlling the flow of liquid refrigerant. The MPG control valves 411, 412, 421, 422, 431, and 432 are provided in gas side refrigerant pipes 53 to 55, which are refrigerant flow paths in the MP device 40, and have the function of controlling the flow of gaseous refrigerant.

[0072] According to this, the MP device 40 has an MPL control valve 44 that is common to the multiple indoor units 201-203. In other words, by employing the MP device 40, it is no longer necessary to provide an MPL control valve 44 in each of the multiple indoor units 201-203. As a result, according to this embodiment, the number of control valves can be reduced compared to when the SP device 30 is connected to all of the indoor units 201-204. This reduces the number of parts and reduces manufacturing costs, and by reducing the number of control valves with drive units, the maintainability and durability of the air conditioner 1 can be improved.

[0073] Even in the event of a refrigerant leak, there is a desire to continue operation of the air conditioner 1 as long as safety is ensured. On the other hand, if a refrigerant leak poses a risk to safety, it is necessary to reliably shut down operation of the air conditioner 1. Typically, one indoor unit 204 is connected to one SP device 30. On the other hand, multiple indoor units 201-203 are connected to one MP device 40. The amount of refrigerant downstream of the SP device 30 is proportional to the volume of the indoor heat exchanger 21 of the indoor unit 204 connected to the port pair of the SP device 30 and the piping between them. On the other hand, the amount of refrigerant downstream of the MP device 40 is proportional to the volume of all the indoor heat exchangers 21 of the multiple indoor units 201-203 connected to each port pair of the MP device 40 and the piping between them. Because the MP device 40 is connected to multiple indoor units 201-203, the amount of refrigerant downstream is several times greater than that of an SP device 30, which is generally connected to only one indoor unit 204. In other words, the amount of refrigerant downstream of the SP device 30 is small.

[0074] For example, the maximum cooling rated capacity of indoor units that can be connected to SP device 30 is approximately 28 kW, whereas the total cooling rated capacity of indoor units that can be connected to MP device 40 is 70 to 110 kW. Because the volume of the indoor heat exchanger of the indoor unit is roughly proportional to the cooling rated capacity of the indoor unit, the amount of refrigerant downstream of SP device 30 is approximately 1 / 3 to 1 / 4 of the amount of refrigerant downstream of MP device 40. Therefore, if the indoor unit in which a refrigerant leak is detected is shut off and separated from the refrigeration cycle, when refrigerant leaks in indoor unit 204 connected to SP device 30, the absolute amount of leaked refrigerant will be smaller than when refrigerant leaks in indoor units 201 to 203 connected to MP device 40, and the impact of the refrigerant leak will be smaller.

[0075] Therefore, the air conditioner 1 configured as described above further includes a maintenance processing unit 171. The maintenance processing unit 171 is capable of executing maintenance processing. The maintenance processing includes processing for closing the SPL control valve 31 and the SPG control valves 321 and 322 in the indoor unit 204, i.e., blocking the flow of refrigerant, and stopping operation of the indoor unit 204 when the leak detection sensor 24 provided in the indoor unit 204 connected to the SP device 30 detects a refrigerant leak. In this way, by isolating the indoor unit 204 from the refrigerant flow path in the refrigeration cycle, refrigerant present in the other indoor units 201 to 203, the outdoor unit 10, and their piping is prevented from flowing into the indoor unit 204. As a result, the amount of refrigerant leaking from the indoor unit 204 can be kept within the range of refrigerant contained in the indoor unit 204 itself. The maintenance process includes a process of maintaining the indoor units 201 to 203 other than the indoor unit 204 in operation after taking measures to suppress the refrigerant leakage described above.

[0076] According to this, if a refrigerant leak occurs in the indoor unit 204 connected to the SP device 30, which is less affected by the refrigerant leak, it is possible to stop operation of only the indoor unit 204 connected to the SP device 30, while continuing operation of the other indoor units, i.e., the indoor units 201 to 203 connected to the MP device 40. Therefore, according to this embodiment, it is possible to improve user convenience without compromising safety and reliability in the event of a refrigerant leak.

[0077] On the other hand, the amount of refrigerant flowing through the MP device 40 is greater than the amount of refrigerant flowing through the SP device 30. The MP device 40 is provided with only one MPL control valve 44 between it and the liquid-side refrigerant pipe 56. Therefore, if a refrigerant leak is detected in any of the indoor units 201-203 connected to the MP device 40, shutting off the MPL control valve 44 and all of the MPG control valves 411, 412, 421, 422, 431, and 432 will prevent refrigerant from flowing between the indoor units 201-203 and other refrigeration cycle equipment, including the outdoor unit 10. However, refrigerant can still flow between the indoor units 201-203 through the liquid-side refrigerant pipes 561-563. Therefore, if a refrigerant leak occurs in any of the indoor units 201-203, refrigerant present in the other indoor units connected to the MP device 40 and in their piping that are not leaking refrigerant may flow into the leaking indoor unit, resulting in a large amount of refrigerant leakage. In other words, if refrigerant leaks in any of the indoor units 201 to 203 connected to the MP device 40, the amount of leaked refrigerant will be greater than if refrigerant leaks in the indoor unit 204 connected to the SP device 30, and the impact of the refrigerant leakage will be greater.

[0078] Therefore, the air conditioner 1 configured as described above further includes a recovery processing unit 172 and a total stop processing unit 173. The recovery processing unit 172 executes a recovery process that recovers refrigerant present in the indoor units 201-204 to the outdoor unit 10. When at least one of the leak detection sensors 24 provided in each of the indoor units 201-203 connected to the MP device 40 detects a refrigerant leak, the recovery process operates the compressor 14 with the MPL control valve 44 and the SPL control valve 31 closed, and recovers refrigerant remaining in the heat exchangers 21 of each indoor unit 201-204 (in this case, all of the indoor heat exchangers 21 and their peripheral piping 511, 561-563, 52-55 provided in the air conditioner 1) to the compressor 14. In this case, the MPG control valves 411, 412, 421, 422, 431, 432 and the SPG control valves 321, 322 are maintained in an open state. Then, after the recovery of the refrigerant described above is completed, the recovery process closes all of the MPG control valves 411, 412, 421, 422, 431, 432 and SPG control valves 321, 322 to stop the compressor 14. As a result, almost no refrigerant remains in all of the indoor units 201-204, and further refrigerant leakage is suppressed.

[0079] Here, if a refrigerant leak occurs in the indoor unit 204 connected to the SP device 30, by separating the indoor unit 204 from the refrigeration cycle as described above, there is no problem in continuing to operate the other indoor units 201 to 203. However, in order to prioritize safety, there is also a need to perform recovery processing even if a refrigerant leak occurs in the indoor unit 204 connected to the SP device 30.

[0080] Therefore, the air conditioning apparatus 1 is further equipped with a setting processing unit 174 that is capable of executing setting processing. The setting processing includes processing that sets, based on input from the user, whether maintenance processing or recovery processing will be executed when the leak detection sensor 24 provided in the indoor unit 204 connected to the SP device 30 detects a refrigerant leak. Then, when the leak detection sensor 24 provided in the indoor unit 204 connected to the SP device 30 detects a refrigerant leak and recovery processing has been set in the setting processing, the recovery processing unit 172 executes the recovery processing. In other words, when the leak detection sensor 24 provided in the indoor unit 204 connected to the SP device 30 detects a refrigerant leak and maintenance processing has been set in the setting processing, the recovery processing unit 172 executes the maintenance processing without executing the recovery processing.

[0081] This allows the user to freely set whether to prioritize maintenance processing or recovery processing when a refrigerant leak occurs in an indoor unit 204 connected to the SP device 30. As a result, it is possible to improve user convenience and provide an air conditioning device 1 that meets the user's needs.

[0082] The air conditioning apparatus 1 is further equipped with a total stop processing unit 173 that, after the recovery processing is completed, is capable of executing total stop processing that prohibits the operation of all of the indoor units 201 to 204. In other words, the total stop processing unit 173, which operates following the recovery processing unit 172, executes total stop processing that prohibits the operation of all of the indoor units 201 to 204 thereafter.

[0083] According to this, if a refrigerant leak occurs in the indoor units 201-203 connected to the MP device 40, the refrigerant is recovered from all of the indoor units 201-204, and then operation of all of the indoor units 201-204 is stopped. This prevents the refrigerant leak from spreading further, ensuring safety.

[0084] Just to be sure, if multiple SP devices 30 are connected to the outdoor unit 10 and maintenance processing is set, even if a leak is detected in an indoor unit connected to one of the SP devices 30, that SP device 30 will be cut off from the refrigeration cycle, but the other SP devices and the indoor units connected to that SP device 30 will continue to operate. On the other hand, if recovery processing is set, refrigerant will be recovered from all SP devices 30 and MP devices 40, and operation will be prohibited.

[0085] Furthermore, while the selection and setting of the maintenance process and recovery process for the SP device 30 described above was set uniformly for the entire system of the air conditioning apparatus 1, when multiple SP devices 30 are connected, it may be set for each individual SP device 30 or for each indoor unit connected to each SP device 30. In this case, if the "maintenance process" is set for the indoor unit in which a refrigerant leak has been detected or the SP device 30 corresponding to that indoor unit, when a refrigerant leak from that indoor unit is detected, the shutoff valve of the corresponding SP device 30 simply shuts off the refrigerant flow, allowing the other SP devices 30 and MP devices 40 to continue air conditioning operation. On the other hand, if the "recovery process" is set for the indoor unit in which a refrigerant leak has been detected or the SP device 30 corresponding to that indoor unit, when a refrigerant leak from that indoor unit is detected, refrigerant recovery is performed for the entire refrigeration cycle, and future air conditioning operation is prohibited in all indoor units connected to the SP devices 30 and MP devices 40.

[0086] The air conditioning apparatus 1 further includes a first notification processing section 175 capable of executing a first notification processing section, or a second notification processing section 176 capable of executing a second notification processing section. The first notification processing section is a process for notifying the user that, when maintenance processing is executed, the indoor unit from which refrigerant has leaked cannot operate, but that indoor units other than the indoor unit from which the refrigerant has leaked can continue to operate. The second notification processing section is a process for notifying the user that, when total stop processing is executed, operation of all indoor units is impossible. These processes enable the user to understand any abnormalities that have occurred in the air conditioning apparatus 1 and the subsequent response, improving user convenience.

[0087] The number of indoor units that can be connected to the MP device 40 is set to between 2 and 8. For this reason, the amount of refrigerant downstream of the MP device 40 is greater than that of the SP device 30, which is basically connected to one indoor unit. Therefore, if refrigerant leaks from one of the indoor units connected to the MP device 40, operation can be discontinued and a refrigerant recovery process can be performed to prevent the amount of refrigerant leakage from increasing.

[0088] As described above, when a refrigerant leak is detected in an indoor unit 204 connected to the SP device 30, the air conditioner 1 of this embodiment closes the SPL control valve 31 and the SPG control valves 321, 322 to isolate the indoor unit 204 from the refrigeration cycle system and stop its operation, while maintaining the indoor units 201-203 other than the indoor unit 204 in operation. On the other hand, when a refrigerant leak is detected in the indoor units 201-203 connected to the MP device 40, the refrigerant is recovered from all of the indoor units 201-204 and sealed on the outdoor unit 10 side, and subsequent operation of all of the indoor units 201-204 is stopped and prohibited. In this way, the multi-type air conditioner 1 can ensure safety and reliability against refrigerant leaks while minimizing the number of valves.

[0089] The number of SP units 30 and the number of MP units 40 provided in the multi-type air conditioner 1 are not limited to those described above. For example, multiple MP units 40 and multiple SP units 30 may be connected to form a single refrigeration cycle. Furthermore, the number of indoor units connected to the SP unit 30 and the number of indoor units connected to the MP unit 40 are not limited to those described above. As described above, the MP unit 40 can be available in a lineup ranging from models that can connect two indoor units to models that can connect up to eight indoor units, or even more. In principle, the SP unit 30 is designed to connect to one indoor unit, but it is possible to connect multiple indoor units in parallel to the piping downstream of the SP unit 30. However, the SP unit 30 has limited capacity for indoor units that can be connected. Because the downstream liquid-side refrigerant pipe 511 and gas-side refrigerant pipe 52 have narrow diameters, indoor units with high capacity cannot be connected, and the amount of refrigerant downstream of the SP unit 30 is small.

[0090] Furthermore, it is not necessary for all indoor units to be provided with the leak detection sensor 24. For example, if multiple indoor units are installed in the same space, it is sufficient to install at least one leak detection sensor 24 in each space.

[0091] In this embodiment, various processes such as maintenance and recovery processes in the event of a refrigerant leak in the indoor unit of the air conditioner 1 are executed by the outdoor control unit 10, but these processes may be executed by any controller connected by a communication line and capable of sharing information. For example, if one of the controllers of the indoor unit, MP device 40, or SP device 30 is set as the master and the controllers of other devices, including the outdoor control unit 17, are set as slaves, the master controller can issue instructions to the slave controllers to execute the same processes as those described above. Furthermore, a centralized control device that manages the entire air conditioner 1 may be connected to the communication line between the indoor control unit 25 and the outdoor control unit 17 so that it can communicate with each other, and the centralized control device may be responsible for executing various processes in the event of a refrigerant leak.

[0092] Although one embodiment of the present invention has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, modifications, and combinations of configurations and controls can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as defined in the claims. [Explanation of symbols]

[0093] 1... multi-type air conditioner, 10... outdoor unit, 11... outdoor heat exchanger, 14... compressor, 171... maintenance processing unit, 172... recovery processing unit, 173... total stop processing unit, 174... setting processing unit, 175... first alarm processing unit, 176... second alarm processing unit, 201, 202, 203, 304... indoor unit, 21... indoor heat exchanger, 24... leak detection sensor, 30... single-port shut-off valve device, 31... single-port liquid-side control valve, 321, 322... single-port gas control valve, 40... multi-port shut-off valve device, 411, 412, 421, 422, 431, 432... multi-port gas control valve, 44... multi-port liquid-side control valve

Claims

1. Simultaneous cooling and heating operation is possible, an outdoor unit having an outdoor heat exchanger and a compressor; a plurality of indoor units each having an indoor heat exchanger connected to the outdoor heat exchanger and the compressor, and a leakage detection sensor capable of detecting refrigerant leakage; a single-port shutoff valve device capable of controlling the flow of refrigerant through one refrigerant flow passage to which one of the indoor units is connected; a multi-port shutoff valve device capable of controlling the flow of refrigerant through a plurality of refrigerant flow passages to which the plurality of indoor units are connected; Equipped with The single-port shut-off valve device is a single-port liquid-side control valve provided in the refrigerant flow passage of the single-port shutoff valve device to control the flow of liquid refrigerant; a single-port gas control valve provided in the refrigerant flow passage of the single-port shutoff valve device to control the flow of gaseous refrigerant; and The multi-port shut-off valve device is a multi-port liquid-side control valve provided in common to the indoor units in the multi-port shutoff valve device and controlling the flow of liquid refrigerant; a multi-port gas control valve provided in the refrigerant flow passage of the multi-port shutoff valve device to control the flow of gaseous refrigerant; and a maintenance processing unit that, when the leakage detection sensor provided in the indoor unit connected to the single-port shutoff valve device detects a refrigerant leakage, closes the single-port liquid-side control valve and the single-port gas control valve corresponding to the indoor unit to stop operation of the indoor unit and maintains the indoor units other than the indoor unit in an operable state; a recovery processing unit that is capable of executing a recovery process in which, when the leakage detection sensors provided in the indoor units connected to the multi-port shutoff valve device detect refrigerant leakage, the compressor is operated with the multi-port liquid-side control valve and the single-port liquid-side control valve closed to recover refrigerant remaining in each of the indoor heat exchangers to the compressor side, and after the refrigerant recovery is completed, all of the multi-port gas control valves and the single-port gas control valves are closed to stop the compressor. Multi-type air conditioning unit.

2. a setting processing unit that can execute a setting process to set, based on input from a user, whether the maintenance process or the recovery process will be executed when the leakage detection sensor provided in the indoor unit connected to the single-port shutoff valve device detects a refrigerant leakage; The recovery processing unit executes the recovery processing when the leakage detection sensor provided in the indoor unit connected to the single-port shutoff valve device detects a refrigerant leakage and when the recovery processing is set in the setting processing. The multi-type air conditioner according to claim 1.

3. Further, a total stop processing unit is provided which can execute a total stop processing for prohibiting operation of all the indoor units after the recovery processing is completed.

3. A multi-type air conditioner according to claim 1 or 2.

4. The air conditioner further includes a first notification processing unit capable of executing a first notification processing to notify the user that, when the maintenance processing is executed, the indoor unit from which the refrigerant has leaked cannot operate but the indoor units other than the indoor unit from which the refrigerant has leaked can continue to operate.

3. A multi-type air conditioner according to claim 1 or 2.

5. The air conditioner further includes a second notification processing unit that can execute a second notification processing to notify the user that operation of all of the indoor units is impossible when the total stop processing is executed. The multi-type air conditioner according to claim 3.

6. the number of connectable indoor units of the multi-port shutoff valve device is set to 2 or more and 8 or less, The multi-type air conditioner according to claim 1.

Images