Air conditioning and water heating system, method for controlling air conditioning and water heating system, and control device

Abstract

An air conditioning and water heating system comprising: an outdoor unit that comprises a compressor which compresses a first heat medium, and that supplies the first heat medium; a water heating unit that generates hot water using the first heat medium supplied from the outdoor unit; an indoor unit that performs air conditioning using the first heat medium supplied from the outdoor unit; a cutoff unit that cuts off the first heat medium flowing into the indoor unit; and a control unit that, when the first heat medium has leaked in the indoor unit, performs control to cut off the first heat medium flowing into the indoor unit using the cutoff unit, continue the running of the compressor, and continue the supply of the first heat medium from the outdoor unit to the water heating unit.

Description

Air conditioning and hot water supply system, and control method and control device for air conditioning and hot water supply system

[0001] The present disclosure relates to an air conditioning and hot water supply system, and a control method and control device for the air conditioning and hot water supply system.

[0002] Patent document 1 discloses an air conditioning and hot water supply system comprising an outdoor unit, a plurality of indoor units each connected to the outdoor unit, and a hot water supply unit connected to the outdoor unit so as to be arranged in parallel with the plurality of indoor units.

[0003] Patent Document 2 discloses an air conditioner in which an outdoor unit and multiple indoor units are connected by refrigerant piping. Patent Document 2 discloses that an externally attached device is provided that has an expansion valve provided on one side of multiple refrigerant piping connecting the indoor unit and the outdoor unit and a solenoid valve provided on the other side, and that the expansion valve and the solenoid valve are closed in the event of a refrigerant leak.

[0004] JP 2019-529857 A JP 2012-013339 A

[0005] BACKGROUND ART In an air conditioning and hot water supply system that performs air conditioning and hot water supply, it is required to continue the hot water supply function in the event of a refrigerant leak in an indoor unit.

[0006] The present disclosure provides a technique for continuing operation of a hot water supply unit when a refrigerant leaks in an indoor unit.

[0007] An air conditioning and hot water supply system according to a first aspect includes: an outdoor unit having a compressor that compresses a first heat medium and supplies the first heat medium; a hot water supply unit that generates hot water using the first heat medium supplied from the outdoor unit; an indoor unit that performs air conditioning using the first heat medium supplied from the outdoor unit; a shut-off unit that shuts off the first heat medium flowing to the indoor unit; and a control unit that, when the first heat medium leaks in the indoor unit, controls the shut-off unit to shut off the first heat medium flowing to the indoor unit, continues operating the compressor, and continues supplying the first heat medium from the outdoor unit to the hot water supply unit.

[0008] According to the air conditioning and hot water supply system of the first aspect, even if a refrigerant leaks in the indoor unit, the hot water supply unit can continue to operate.

[0009] An air conditioning and hot water supply system according to a second aspect is the air conditioning and hot water supply system according to the first aspect, wherein the hot water supply unit includes a cascade heat medium circuit that produces hot water using a second heat medium that has exchanged heat with the first heat medium.

[0010] An air conditioning and hot water supply system according to a third aspect is the air conditioning and hot water supply system according to the second aspect, wherein the cascade heat medium circuit continues circulating the second heat medium when the first heat medium leaks in the indoor unit.

[0011] The air conditioning and hot water supply system of a fourth aspect is the air conditioning and hot water supply system of the second aspect or the third aspect, wherein the first heat medium is R32, and the second heat medium is 1234yf.

[0012] An air conditioning and hot water supply system according to a fifth aspect is the air conditioning and hot water supply system according to any one of the first aspect to the fourth aspect, wherein the indoor unit includes an expansion valve, and the expansion valve functions as a shutoff valve in the shutoff unit.

[0013] An air conditioning and hot water supply system according to a sixth aspect is the air conditioning and hot water supply system according to any one of the first aspect to the fifth aspect, wherein, after the shutoff unit is shut off, the amount m of the first heat medium released from the indoor unit satisfies Equation 1.

[0014] where max(a, b) is a function that returns the larger of a and b, min(a, b) is a function that returns the smaller of a and b, and LFL is the lower flammability limit of the heat transfer medium (unit: kilogram per cubic meter (kg / m ３ )), A is the minimum room area (unit: square meters (m ２ )), h ０ is the floor height (unit: meters (m)), SF is a constant (0.5), and the floor height h ０ is calculated based on Equation 4.

[0015] However, h ｉｎｓｔ is the height of the bottom surface of the product from the floor, h ｒｅｌis the height from the bottom of the product of the opening that results in a cumulative open area of ​​5 square centimeters from the bottom (excluding holes with dimensions of 0.1 millimeters or less).

[0016] An air conditioning and hot water supply system according to a seventh aspect is the air conditioning and hot water supply system according to any one of the first aspect to the sixth aspect, comprising a plurality of indoor units, each of which has a plurality of shut-off units provided for each indoor unit, and wherein the control unit shuts off the first heat medium using the shut-off unit in the indoor unit from which the first heat medium has leaked, and controls to continue supplying the first heat medium to the indoor units other than the indoor unit from which the first heat medium has leaked.

[0017] An air conditioning and hot water supply system according to an eighth aspect is the air conditioning and hot water supply system according to any one of the first aspect to the seventh aspect, wherein the first heat medium is a slightly flammable refrigerant or a flammable refrigerant.

[0018] An air conditioning and hot water supply system according to a ninth aspect is the air conditioning and hot water supply system according to any one of the first aspect to the eighth aspect, wherein the first heat medium is R32.

[0019] An air conditioning and hot water supply system according to a tenth aspect is the air conditioning and hot water supply system according to any one of the first to ninth aspects, wherein operation of the compressor is stopped when the capacity of the indoor unit with the shutoff unit closed is equal to or greater than a predetermined capacity relative to the capacity of the outdoor unit.

[0020] A first aspect of the control method for an air conditioning and hot water supply system is a control method for an air conditioning and hot water supply system comprising: an outdoor unit having a compressor that compresses a first heat medium and supplies the first heat medium; a hot water supply unit that generates hot water using the first heat medium supplied from the outdoor unit; an indoor unit that performs air conditioning using the first heat medium supplied from the outdoor unit; and a shut-off unit that shuts off the first heat medium flowing to the indoor unit, wherein when the first heat medium leaks in the indoor unit, the shut-off unit shuts off the first heat medium flowing to the indoor unit, the compressor continues to operate, and the supply of the first heat medium from the outdoor unit to the hot water supply unit continues.

[0021] According to the control method for an air conditioning and hot water supply system of the first aspect, the hot water supply function can be continued even if refrigerant leaks in the indoor unit.

[0022] A control device of a first aspect is a control device used in an air conditioning and hot water supply system comprising: an outdoor unit having a compressor that compresses a first heat medium and supplies the first heat medium; a hot water supply unit that generates hot water using the first heat medium supplied from the outdoor unit; an indoor unit that performs air conditioning using the first heat medium supplied from the outdoor unit; and a shut-off unit that shuts off the first heat medium flowing to the indoor unit, wherein when the first heat medium leaks in the indoor unit, the shut-off unit shuts off the first heat medium flowing to the indoor unit, and the control device continues to operate the compressor and controls to continue the supply of the first heat medium from the outdoor unit to the hot water supply unit.

[0023] According to the control device of the first aspect, the hot water supply function can be continued in the event of a refrigerant leak in the indoor unit.

[0024] FIG. 1 is a diagram showing an outline of the configuration of an air conditioning hot water supply system according to a first embodiment. FIG. 2 is a diagram showing an outline of an outdoor unit provided in the air conditioning hot water supply system according to the first embodiment. FIG. 3 is a diagram showing an outline of a hot water supply unit provided in the air conditioning hot water supply system according to the first embodiment. FIG. 4 is a diagram showing an outline of an indoor unit and a shut-off unit provided in the air conditioning hot water supply system according to the first embodiment. FIG. 5 is a diagram showing the hardware configuration of a control unit provided in the air conditioning hot water supply system according to the first embodiment. FIG. 6 is a diagram showing an outline of a cooling / heating switching unit provided in the air conditioning hot water supply system according to the first embodiment. FIG. 7 is a flow chart showing the processing of the air conditioning hot water supply system according to the first embodiment. FIG. 8 is a diagram showing an outline of the configuration of an air conditioning hot water supply system according to a second embodiment.

[0025] Hereinafter, embodiments will be described with reference to the accompanying drawings. Note that, in the description of the specification and drawings relating to each embodiment, components having substantially the same or corresponding functional configurations may be designated by the same reference numerals, and redundant explanations may be omitted. Furthermore, to facilitate understanding, the scale of each part in the drawings may differ from the actual scale.

[0026] First Embodiment An air conditioning and hot water supply system according to the first embodiment will be described. The air conditioning and hot water supply system according to the first embodiment includes an outdoor unit, a hot water supply unit, an indoor unit, a shut-off unit, and a control unit. The outdoor unit in the air conditioning and hot water supply system according to the first embodiment includes a compressor that compresses a first heat medium and supplies the first heat medium. The hot water supply unit in the air conditioning and hot water supply system according to the first embodiment generates hot water using the first heat medium supplied from the outdoor unit. The indoor unit in the air conditioning and hot water supply system according to the first embodiment performs air conditioning using the first heat medium supplied from the outdoor unit. The shut-off unit in the air conditioning and hot water supply system according to the first embodiment shuts off the first heat medium flowing to the indoor unit. The control unit in the air conditioning and hot water supply system according to the first embodiment controls the shut-off unit to shut off the first heat medium flowing to the indoor unit when the first heat medium leaks in the indoor unit. In addition, when the first heat medium leaks in the indoor unit, the control unit in the air conditioning and hot water supply system of the first embodiment controls the compressor to continue operating and to continue supplying the first heat medium from the outdoor unit to the hot water supply unit.

[0027] FIG. 1 is a diagram showing an outline of the configuration of an air conditioning and hot water supply system 1, which is an example of an air conditioning and hot water supply system according to the first embodiment.

[0028] [Air Conditioning and Hot Water Supply System 1] The air conditioning and hot water supply system 1 generates hot water (hot water supply) and conditions a predetermined space. The air conditioning and hot water supply system 1 is a so-called heat pump type air conditioning and hot water supply system. The air conditioning and hot water supply system 1 can, for example, supply hot water while heating and while cooling.

[0029] The air conditioning and hot water supply system 1 includes an outdoor unit 10, a hot water supply unit 20, an indoor unit 30, a shutoff unit 40, and a control unit 50. The air conditioning and hot water supply system 1 also includes a cooling / heating switching unit 60a between the outdoor unit 10 and the hot water supply unit 20. The air conditioning and hot water supply system 1 also includes a cooling / heating switching unit 60b between the outdoor unit 10 and the indoor unit 30. Each of the components included in the air conditioning and hot water supply system 1 will now be described in detail.

[0030] (Outdoor unit 10) Details of the outdoor unit 10 will be described below. Fig. 2 is a diagram showing an overview of the outdoor unit 10 provided in the air conditioning and hot water supply system 1, which is an example of the air conditioning and hot water supply system according to the first embodiment.

[0031] The outdoor unit 10 supplies the first heat medium RF1 to each of the hot water supply unit 20 and the indoor unit 30. The outdoor unit 10 is installed outdoors, for example, on the rooftop or balcony of a building. The outdoor unit 10 is also installed underground, for example. The outdoor unit 10 uses, for example, R32, an alternative to chlorofluorocarbon, as the first heat medium RF1. Note that the outdoor unit 10 may use, for example, propane as the first heat medium RF1. Alternatively, R454B may be used as the first heat medium RF1.

[0032] R32 is a slightly flammable refrigerant, and propane is a flammable refrigerant.

[0033] The outdoor unit 10 includes a compressor 11, an accumulator 12, heat exchangers 13a and 13b, expansion valves 14a and 14b, four-way switching valves 15a, 15b and 15c, and a fan 16.

[0034] The compressor 11 compresses the first heat medium RF1. The compressor 11 is, for example, a scroll or rotary type positive displacement compressor having a sealed structure with a built-in compressor motor. The compressor 11 compresses the low-pressure first heat medium RF1 that has been sucked in. The compressor 11 then discharges the compressed first heat medium RF1.

[0035] The accumulator 12 temporarily stores the low-pressure first heat medium RF1 that is sucked into the compressor 11. The accumulator 12 temporarily stores the first heat medium RF1, thereby separating the first heat medium RF1 into gas and liquid.

[0036] The heat exchanger 13a and the heat exchanger 13b exchange heat between the first heat medium RF1 and the outside air. Each of the heat exchanger 13a and the heat exchanger 13b is, for example, a cross-fin type or a microchannel type heat exchanger.

[0037] The expansion valves 14a and 14b each reduce the pressure of the first heat medium RF1 passing therethrough. Each of the expansion valves 14a and 14b is, for example, an electrically operated valve whose opening degree is adjustable.

[0038] The four-way switching valve 15 a, the four-way switching valve 15 b, and the four-way switching valve 15 c each switch the flow of the first heat medium RF1. Each of the four-way switching valve 15 a, the four-way switching valve 15 b, and the four-way switching valve 15 c has one flow path closed, and therefore essentially functions as a three-way valve.

[0039] The fan 16 generates a flow of air that flows through the heat exchangers 13a and 13b. The fan 16 is, for example, an axial flow fan.

[0040] The outdoor unit 10 is connected to a liquid communication pipe RL1, an intake gas communication pipe RL2, and a high- and low-pressure gas communication pipe RL3.

[0041] The air conditioning and hot water supply system 1 generates hot water in the hot water supply unit 20, and performs heating and cooling operations in the indoor unit 30. The operation of the outdoor unit 10 when the indoor unit 30 performs heating operation and cooling operation will be described below.

[0042] (1) Heating Operation When the indoor unit 30 performs heating operation, the first heat medium RF1 compressed in the compressor 11 passes through the four-way switching valve 15c and is discharged from the high-low pressure gas communication pipe RL3.

[0043] The first heat medium RF1 returning from the liquid connection pipe RL1 branches to flow to the expansion valve 14a and the expansion valve 14b, respectively. The first heat medium RF1 branched to the expansion valve 14a side is depressurized when passing through the expansion valve 14a. The first heat medium RF1 depressurized in the expansion valve 14a then exchanges heat with the outdoor air and evaporates when passing through the heat exchanger 13a. The first heat medium RF1 evaporated in the heat exchanger 13a then passes through the four-way switching valve 15a and the accumulator 12, and is sucked into the compressor 11. Similarly, the first heat medium RF1 branched to the expansion valve 14b side is depressurized when passing through the expansion valve 14b. The first heat medium RF1 depressurized in the expansion valve 14b then exchanges heat with the outdoor air and evaporates when passing through the heat exchanger 13b. The first heat medium RF1 evaporated in the heat exchanger 13 a passes through the four-way selector valve 15 b and the accumulator 12 and is sucked into the compressor 11 .

[0044] (2) Cooling Operation (Cooling + Hot Water Supply) When the indoor unit 30 performs cooling operation, the first heat medium RF1 compressed in the compressor 11 is branched to flow to each of the four-way switching valves 15a and 15c. The first heat medium RF1 branched to the four-way switching valve 15a side exchanges heat with outdoor air in the heat exchanger 13a and is condensed. The first heat medium RF1 condensed in the heat exchanger 13a then passes through the expansion valve 14a and is discharged from the liquid connection pipe RL1. The first heat medium RF1 branched to the four-way switching valve 15c is discharged from the high-low pressure gas connection pipe RL3.

[0045] The first heat medium RF1 returning from the intake gas communication pipe RL2 passes through the accumulator 12 and is sucked into the compressor 11.

[0046] (Hot Water Supply Unit 20) The hot water supply unit 20 generates hot water using the first heat medium RF1 supplied from the outdoor unit 10.

[0047] FIG. 3 is a diagram showing an overview of a hot water supply unit 20 provided in an air conditioning and hot water supply system 1, which is an example of the air conditioning and hot water supply system according to the first embodiment.

[0048] The hot water supply unit 20 includes a cascade heat medium circuit 20s using a second heat medium RF2 that has exchanged heat with the first heat medium RF1. The cascade heat medium circuit 20s produces hot water.

[0049] The hot water supply unit 20 is integrated with, for example, the outdoor unit 10. The hot water supply unit 20 integrated with the outdoor unit 10 is installed outdoors, for example, on the rooftop or balcony of a building. The hot water supply unit 20 is also installed underground, for example. The hot water supply unit 20 uses, for example, 1234yf, an alternative chlorofluorocarbon, as the second heat medium RF2. 1234yf is a mildly flammable refrigerant (mildly flammable refrigerant). Note that 1234ze may also be used as the second heat medium RF2. The combination of the first heat medium RF1 and the second heat medium RF is not limited to the combination of R32 and 1234yf, and may be, for example, any of the combinations of R454B and 1234yf, RF454B and 1234ze, and R32 and 1234ze.

[0050] The hot water supply unit 20 includes a compressor 21, an accumulator 22, a heat exchanger 23, a heat exchanger 24, an expansion valve 25, an expansion valve 26, a pump 27, a four-way switching valve 28, a check valve 29a, and a check valve 29b.

[0051] The compressor 21 compresses the second heat medium RF2. The compressor 21 is, for example, a scroll or rotary type positive displacement compressor having a sealed structure with a built-in compressor motor. The compressor 21 compresses the low-pressure second heat medium RF2 that has been sucked in. Then, the compressor 21 discharges the compressed second heat medium RF2.

[0052] The accumulator 22 temporarily stores the low-pressure second heat medium RF2 that is sucked into the compressor 21. The accumulator 22 temporarily stores the second heat medium RF2, thereby separating the second heat medium RF2 into gas and liquid.

[0053] The heat exchanger 23 exchanges heat between the first heat medium RF1 and the second heat medium RF2. The heat exchanger 23 is, for example, a plate-type or spiral-type heat exchanger.

[0054] The heat exchanger 24 exchanges heat between the second heat medium RF2 and water. The heat exchanger 24 is, for example, a double-pipe heat exchanger.

[0055] The expansion valve 25 reduces the pressure of the first heat medium RF1 passing therethrough. The expansion valve 26 reduces the pressure of the second heat medium RF2 passing therethrough. Each of the expansion valves 25 and 26 is, for example, an electrically operated valve whose opening degree is adjustable.

[0056] The pump 27 pumps the water to the heat exchanger 24 .

[0057] The four-way switching valve 28 switches the flow of the second heat medium RF2.

[0058] The check valve 29a prevents the second heat medium RF2 from flowing back to the compressor 21. The check valve 29b prevents water from flowing back.

[0059] (Indoor Unit 30) The indoor unit 30 conditions the air in a predetermined space RM.

[0060] FIG. 4 is a diagram showing an overview of an indoor unit 30 and a shutoff unit 40 provided in an air conditioning and hot water supply system 1, which is an example of the air conditioning and hot water supply system according to the first embodiment.

[0061] The indoor unit 30 includes a heat exchanger 31, an expansion valve 32, a detector 33, and a fan 34.

[0062] The heat exchanger 31 exchanges heat between the first heat medium RF1 and air. The heat exchanger 31 is, for example, a cross-fin type or micro-channel type heat exchanger.

[0063] The expansion valve 32 reduces the pressure of the first heat medium RF1 passing through the inside of the expansion valve 32. The expansion valve 32 is, for example, an electrically operated valve whose opening degree is adjustable.

[0064] The detector 33 detects the first heat medium RF1. The detector 33 detects the first heat medium RF1, thereby detecting leakage of the first heat medium RF1.

[0065] The fan 34 generates an air flow that passes through the heat exchanger 31. The fan 34 is, for example, a sirocco fan.

[0066] (Shut-off Unit 40 ) The shut-off unit 40 shuts off the first heat medium RF1 flowing from the outdoor unit 10 to the indoor unit 30 .

[0067] The shutoff unit 40 includes a shutoff valve 41 and a shutoff valve 42. Each of the shutoff valve 41 and the shutoff valve 42 is, for example, a motor-operated valve.

[0068] For example, when the detector 33 provided in the indoor unit 30 detects leakage of the first heat medium RF1, the shutoff unit 40 closes the shutoff valves 41 and 42. Then, the shutoff unit 40 cuts off the supply of the first heat medium RF1 to the indoor unit 30.

[0069] The following describes the amount of the first heat medium RF1 released from the indoor unit 30 after the shutoff unit 40 is shut off. In other words, the following describes the amount of the first heat medium RF1 remaining on the indoor unit 30 side from the shutoff unit 40 after the shutoff unit 40 is shut off.

[0070] It is desirable that the amount m of the first heat medium RF1 released from the indoor unit 30 after the shutoff unit 40 is shut off satisfies formula A.

[0071]

[0072] where max(a, b) is a function that returns the larger of a and b, and min(a, b) is a function that returns the smaller of a and b. LFL is the lower flammability limit (unit: kilogram per cubic meter (kg / m ３ When the first heat medium RF1 is R32, the LFL is, for example, 0.307 kilograms per cubic meter (kg / m ３ ) A is the minimum room area (unit: square meters (m ２ )), h ０ is the floor height (unit: meters (m)), SF is a constant (0.5). ０ is calculated based on Equation D.

[0073]

[0074] However, h ｉｎｓｔ is the height of the bottom surface of the product from the floor, h ｒｅｌis the height from the bottom of the product of the opening that results in a cumulative open area of ​​5 square centimeters from the bottom (excluding holes with dimensions of 0.1 millimeters or less).

[0075] (Control unit 50) The control unit 50 controls the outdoor unit 10, the hot water supply unit 20, the indoor unit 30, and the cooling / heating switching unit 60a and cooling / heating switching unit 60b. Fig. 5 is a hardware configuration diagram showing the hardware configuration of the control unit 50 provided in the air conditioning and hot water supply system 1, which is an example of the air conditioning and hot water supply system according to the first embodiment.

[0076] The control unit 50 includes a control unit 51, a RAM (Random Access Memory) 52, and a ROM (Read Only Memory) 53. The control unit 50 also includes a storage I / F (Interface) 54 and an external I / F 55. The control unit 51, the RAM 52, the ROM 53, the storage I / F 54, and the external I / F 55 are each connected to the bus B1.

[0077] For example, a storage medium 54a is connected to the storage I / F 54. For example, the outdoor unit 10, the hot water supply unit 20, the indoor unit 30, the cooling / heating switching unit 60a, and the cooling / heating switching unit 60b are connected to the external I / F 55.

[0078] The control unit 51 is a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The control unit 51 may be an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array). The control unit 51 executes a program to perform each process described in this specification. The control unit 51 is a computing device that reads a program (app, application) from a storage device such as the ROM 53 or a storage medium 54a onto the RAM 52 and executes the process. The control unit 51, the RAM 52, and the ROM 53 constitute a computer that controls the air conditioning and hot water supply system 1.

[0079] The RAM 52 is a volatile semiconductor memory that temporarily stores, for example, programs (applications) and the like.

[0080] The ROM 53 is a non-volatile semiconductor memory that can retain programs (apps, applications) even when the power is turned off. The ROM 53 stores programs such as a Basic Input / Output System (BIOS) that is executed at startup, and various settings such as OS (Operating System) settings and network settings.

[0081] The storage I / F 54 is an interface with an external storage device such as a storage medium 54a.

[0082] The storage medium 54a is, for example, a Secure Digital (SD) memory card, a Universal Serial Bus (USB) memory, a Hard Disk Drive (HDD), or a Solid State Drive (SSD).

[0083] The external I / F 55 is an interface that connects peripheral devices to the control unit 51. Via the external I / F 55, the control unit 51 is connected to each of the outdoor unit 10, the hot water supply unit 20, the indoor unit 30, the cooling / heating switching unit 60a, and the cooling / heating switching unit 60b.

[0084] (Cooling / Heating Switching Unit 60a and Cooling / Heating Switching Unit 60b) Each of the cooling / heating switching units 60a and 60b controls the flow path through which the first heat medium RF1 flows so that, for example, cooling, heating, and hot water supply can be performed simultaneously.

[0085] 6 is a diagram showing an overview of a cooling / heating switching unit 60 provided in the air conditioning / hot water supply system 1, which is an example of the air conditioning / hot water supply system according to the first embodiment. Since the cooling / heating switching unit 60a and the cooling / heating switching unit 60b have the same configuration, the cooling / heating switching unit 60a and the cooling / heating switching unit 60b will be described below using the cooling / heating switching unit 60.

[0086] The cooling / heating switching unit 60 includes a heat exchanger 61 , a control valve 62 , a control valve 63 , and a control valve 64 .

[0087] The operation of the cooling / heating switching unit 60 when performing heating operation and cooling operation in the indoor unit 30 will be described.

[0088] (1) Heating Operation When the indoor unit 30 performs heating operation, the control valve 63 connected to the high and low pressure gas communication pipe RL3 is opened in the cooling / heating switching unit 60 connected to each of the hot water supply unit 20 and the indoor unit 30. The control valves 62 and 64 are closed. By opening the control valve 63 and closing the control valves 62 and 64, the first heat medium RF1 that flows in from the high and low pressure gas communication pipe RL3 flows out into the pipe PL2, and the first heat medium RF1 that flows in from the pipe PL1 flows out into the liquid communication pipe RL1.

[0089] (2) Cooling operation (cooling + hot water supply) When the indoor unit 30 performs cooling operation, in the cooling / heating switching unit 60 connected to the hot water supply unit 20, the control valve 63 connected to the high / low pressure gas communication pipe RL3 is opened, and the control valves 62 and 64 are closed. By opening the control valve 63 and closing the control valves 62 and 64, the first heat medium RF1 that flows in from the high / low pressure gas communication pipe RL3 flows out into the pipe PL2, and the first heat medium RF1 that flows in from the pipe PL1 flows out into the liquid communication pipe RL1.

[0090] In the cooling / heating switching unit 60 connected to the indoor unit 30, the control valve 64 connected to the intake gas communication pipe RL2 is opened. The control valves 62 and 63 are closed. By opening the control valve 64 and closing the control valves 62 and 63, the first heat medium RF1 that has flowed in from the liquid communication pipe RL1 flows out into the pipe PL1, and the first heat medium RF1 that has flowed in from the pipe PL2 flows out into the intake gas communication pipe RL2.

[0091] <Processing in the air conditioning and hot water supply system according to the first embodiment> Processing in the air conditioning and hot water supply system according to the first embodiment will be described. Processing will be described using air conditioning and hot water supply system 1, which is an example of the air conditioning and hot water supply system according to the first embodiment. More specifically, processing in control unit 51 of control unit 50 provided in air conditioning and hot water supply system 1 will be described. By describing the processing in control unit 51 of control unit 50 provided in air conditioning and hot water supply system 1, a control method for the air conditioning and hot water supply system according to this embodiment will be described.

[0092] FIG. 7 is a flowchart showing the processing of the air conditioning and hot water supply system 1, which is an example of the air conditioning and hot water supply system according to the first embodiment.

[0093] (Step S10) First, the control unit 51 detects whether there is a leakage of the first heat medium RF1 in the indoor unit 30 (heat medium leakage detection step). Specifically, the control unit 51 obtains information on whether the detector 33 in the indoor unit 30 has detected the first heat medium RF1.

[0094] (Step S20) Next, the control unit 51 determines whether or not there is a leak of the first heat medium RF1 in the indoor unit 30, based on the detection result in step S10. Specifically, if the detector 33 in the indoor unit 30 detects the first heat medium RF1, the control unit 51 determines that there is a leak of the first heat medium RF1 in the indoor unit 30. On the other hand, if the detector 33 in the indoor unit 30 does not detect the first heat medium RF1, the control unit 51 determines that there is no leak of the first heat medium RF1 in the indoor unit 30.

[0095] If it is determined in step S20 that the first heat medium RF1 is leaking from the indoor unit 30 (YES in step S20), the control unit 51 proceeds to step S30. If it is determined in step S20 that the first heat medium RF1 is not leaking from the indoor unit 30 (NO in step S20), the control unit 51 returns to step S10 and repeats the process.

[0096] (Step S30) When it is determined that the first heat medium RF1 is leaking from the indoor unit 30 (YES in step S20), the control unit 51 shuts off the flow of the first heat medium RF1 to the indoor unit 30 using the shutoff unit 40 (shutoff step). Specifically, the control unit 51 closes the shutoff valves 41 and 42 provided in the shutoff unit 40, thereby stopping the supply of the first heat medium RF1 to the indoor unit 30.

[0097] At the time of step S30, the operation of the compressor 11 in the outdoor unit 10 continues. The outdoor unit 10 continues to supply the first heat medium RF1 to the hot water supply unit 20. The second heat medium RF2 also continues to circulate in the hot water supply unit 20. Since the supply of the first heat medium RF1 to the hot water supply unit 20 continues, the air conditioning and hot water supply system 1 can continue to supply hot water.

[0098] In the above example, the control unit 51 closes each of the shutoff valves 41 and 42 provided in the shutoff unit 40, but the control unit 51 may also close the expansion valve 32 provided in the indoor unit 30. When the expansion valve 32 is closed, the shutoff valve 42 in the shutoff unit 40 may or may not be provided.

[0099] (Step S40) Next, the control unit 51 determines whether the capacity of the indoor unit 30 for which the supply of the first heat medium RF1 has been stopped is equal to or greater than a predetermined capacity (capacity determination step). Specifically, the control unit 51 acquires the capacity of the indoor unit 30 for which the shutoff unit 40 has shut off the first heat medium RF1. Then, the control unit 51 determines whether the capacity of the indoor unit 30 for which the shutoff unit 40 has shut off the first heat medium RF1 is equal to or greater than a predetermined capacity.

[0100] The predetermined capacity may be set as appropriate so as to protect the compressor 11 in the outdoor unit 10. The predetermined capacity is, for example, 50% of the capacity of the outdoor unit 10. Note that the predetermined capacity may also be, for example, 20, 25, 30, or 40% of the capacity of the outdoor unit 10.

[0101] If it is determined in step S40 that the capacity of the indoor unit 30 that has stopped the supply of the first heat medium RF1 is equal to or greater than a predetermined capacity (YES in step S40), the control unit 51 proceeds to step S50. If it is determined in step S40 that the capacity of the indoor unit 30 that has stopped the supply of the first heat medium RF1 is less than the predetermined capacity (NO in step S40), the control unit 51 ends the process.

[0102] (Step S50) When it is determined in step S40 that the capacity of the indoor unit 30 to which the supply of the first heat medium RF1 has been stopped is equal to or greater than the predetermined capacity (YES in step S40), the control unit 51 stops the operation of the compressor 11 in the outdoor unit 10 (compressor stopping step). After stopping the operation of the compressor 11, the control unit 51 ends the process.

[0103] The air conditioning hot water supply system according to the first embodiment can continue to provide hot water even if a refrigerant leaks in the indoor unit. In the air conditioning hot water supply system according to the first embodiment, when the first heat medium leaks in the indoor unit, the shut-off unit shuts off the first heat medium flowing to the indoor unit. Furthermore, in the air conditioning hot water supply system according to the first embodiment, when the first heat medium leaks in the indoor unit, the compressor continues to operate, and the supply of the first heat medium from the outdoor unit to the hot water supply unit continues. Therefore, the air conditioning hot water supply system according to the first embodiment can continue to provide hot water even if a refrigerant leaks in the indoor unit.

[0104] Although the air conditioning and hot water supply system 1, which is an example of the air conditioning and hot water supply system according to the first embodiment, has been described as having one indoor unit 30, the air conditioning and hot water supply system according to the first embodiment may include multiple indoor units. All of the multiple indoor units included in the air conditioning and hot water supply system according to the first embodiment may be equipped with a shut-off unit, or at least one indoor unit may be equipped with a shut-off unit.

[0105] When multiple indoor units are provided, all of the multiple indoor units may be in heating operation or cooling operation, or some of the multiple indoor units may be in heating operation and some may be in cooling operation.

[0106] Furthermore, in the air-conditioning hot water supply system 1, which is an example of the air-conditioning hot water supply system according to the first embodiment, an example of control by the controller 51 has been described above. However, in the air-conditioning hot water supply system according to the first embodiment, the functions of the controller are not limited to being realized by the controller 51. The functions of the controller in the air-conditioning hot water supply system according to the first embodiment may be realized, for example, by any of the controllers provided in the outdoor unit, hot water supply unit, indoor unit, and shut-off unit provided in the air-conditioning hot water supply system according to the first embodiment, or may be realized by the cooperation of the respective controllers. Similarly, for example, the functions of the controller may be realized by a controller provided in the cooling / heating switching unit 60 in the air-conditioning hot water supply system 1, which is an example of the air-conditioning hot water supply system according to the first embodiment.

[0107] Furthermore, the control unit in the air conditioning and hot water supply system according to the first embodiment may be provided separately as a control device used in the air conditioning and hot water supply system. In other words, the control unit may be a control device used in an air conditioning and hot water supply system including an outdoor unit, a hot water supply unit, an indoor unit, and a shut-off unit in the air conditioning and hot water supply system according to the first embodiment. Then, when the first heat medium leaks in the indoor unit, the control device may control the shut-off unit to shut off the first heat medium flowing to the indoor unit. Furthermore, when the first heat medium leaks in the indoor unit, the control device may control the compressor to continue operating while continuing the supply of the first heat medium from the outdoor unit to the hot water supply unit.

[0108] Second Embodiment The air conditioning and hot water supply system according to the second embodiment includes a plurality of indoor units. The air conditioning and hot water supply system according to the second embodiment also includes a shutoff unit for each of the plurality of indoor units. In other words, the air conditioning and hot water supply system according to the second embodiment includes a plurality of shutoff units, one for each indoor unit. The control unit in the air conditioning and hot water supply system according to the second embodiment shuts off the first heat medium using the shutoff unit in the indoor unit in which the first heat medium has leaked, and controls the supply of the first heat medium to indoor units other than the indoor unit in which the first heat medium has leaked to be continued.

[0109] FIG. 8 is a diagram showing an outline of the configuration of an air conditioning and hot water supply system 2, which is an example of an air conditioning and hot water supply system according to the second embodiment.

[0110] The air conditioning and hot water supply system 2 includes an indoor unit 30A and an indoor unit 30B. In other words, the air conditioning and hot water supply system 2 includes two indoor units. The air conditioning and hot water supply system 2 also includes a shutoff unit 40A that shuts off the flow of the first heat medium RF1 to the indoor unit 30A when the first heat medium RF1 leaks from the indoor unit 30A. The air conditioning and hot water supply system 2 also includes a shutoff unit 40B that shuts off the flow of the first heat medium RF1 to the indoor unit 30B when the first heat medium RF1 leaks from the indoor unit 30B.

[0111] The air conditioning and hot water supply system 2 includes a control unit 150 instead of the control unit 50 in the air conditioning and hot water supply system 1. The control unit 150 has the functions of the control unit 50 and also controls each of the shutoff unit 40A and the shutoff unit 40B.

[0112] In the air conditioning and hot water supply system 2, there may be a case where the first heat medium RF1 is leaking from either the indoor unit 30A or the indoor unit 30B, while the first heat medium RF1 is not leaking from the other. The control unit in the control unit 150 controls either the shutoff unit 40A or the shutoff unit 40B connected to either the leaking indoor unit 30A or the indoor unit 30B to shut off. Then, the control unit in the control unit 150 controls either the shutoff unit 40A or the shutoff unit 40B connected to the other of the leaking indoor unit 30A or the indoor unit 30B not to shut off.

[0113] The control unit in the control unit 150 shuts off only the shutoff unit connected to the leaking indoor unit, allowing the indoor units that are not leaking to continue operating.

[0114] Although the air conditioning and hot water supply system 2 has been described as having two indoor units, the air conditioning and hot water supply system 2 according to the second embodiment may also have three or more indoor units and the same number of shut-off units as the indoor units.

[0115] According to the air conditioning and hot water supply system of the second embodiment, if a refrigerant leaks in an indoor unit, the hot water supply function can be continued. Also, according to the air conditioning and hot water supply system of the second embodiment, if a refrigerant leaks in an indoor unit, the operation of indoor units that are not leaking refrigerant can be continued.

[0116] When multiple indoor units are provided, all of the multiple indoor units may be in heating operation or cooling operation, or some of the multiple indoor units may be in heating operation and some may be in cooling operation.

[0117] Although the embodiments have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims. Various modifications and improvements, such as combinations and substitutions with part or all of other embodiments, are possible.

[0118] This application claims priority from basic patent application No. 2023-170939, filed with the Japan Patent Office on September 29, 2023, the entire contents of which are incorporated herein by reference.

[0119] 1, 2 Air conditioning and hot water supply system 10 Outdoor unit 11 Compressor 12 Accumulator 13a, 13b Heat exchanger 14a, 14b Expansion valve 15a, 15b, 15c Four-way switching valve 16 Fan 20 Hot water supply unit 20s Cascade heat medium circuit 21 Compressor 22 Accumulator 23, 24 Heat exchanger 25, 26 Expansion valve 27 Pump 28 Four-way switching valve 29a, 29b Check valve 30, 30A, 30B Indoor unit 31 Heat exchanger 32 Expansion valve 33 Detector 34 Fan 40, 40A, 40B Shut-off unit 41, 42 Shut-off valve 50, 150 Control unit 51 Control unit 60, 60a, 60b Cooling / heating switching unit 61 Heat exchanger 62, 63, 64 Control valve RF1 First heat medium RF2 Second heat medium

Claims

1. An air conditioning and hot water supply system comprising: an outdoor unit having a compressor that compresses a first heat medium and supplies the first heat medium; a hot water supply unit that generates hot water using the first heat medium supplied from the outdoor unit; an indoor unit that performs air conditioning using the first heat medium supplied from the outdoor unit; a shutoff unit that shuts off the first heat medium flowing to the indoor unit; and a control unit that, when the first heat medium leaks in the indoor unit, controls the shutoff unit to shut off the first heat medium flowing to the indoor unit, continues operating the compressor, and continues the supply of the first heat medium from the outdoor unit to the hot water supply unit.

2. The air conditioning and hot water supply system according to claim 1, wherein the hot water supply unit includes a cascade heat medium circuit that produces hot water using a second heat medium that has exchanged heat with the first heat medium.

3. The air conditioning and hot water supply system according to claim 2, wherein the cascade heat medium circuit continues circulating the second heat medium when the first heat medium leaks in the indoor unit.

4. The air conditioning and hot water supply system according to claim 2 or 3, wherein the first heat medium is R32, and the second heat medium is 1234yf.

5. An air conditioning and hot water supply system as claimed in any one of claims 1 to 4, wherein the indoor unit is provided with an expansion valve, and the expansion valve functions as a shutoff valve in the shutoff unit.

6. The air conditioning and hot water supply system according to any one of claims 1 to 5, wherein an amount m of the first heat medium discharged from the indoor unit after the shutoff unit is shut off satisfies Equation 1. where max(a, b) is a function that returns the larger of a and b, min(a, b) is a function that returns the smaller of a and b, and LFL is the lower flammability limit of the first heat medium (unit: kilogram per cubic meter (kg / m ３ )), A is the minimum room area (unit: square meters (m ２ )), h ０ is the floor height (unit: meters (m)), SF is a constant (0.5), and the floor height h ０ is calculated based on Equation 4. However, h ｉｎｓｔ is the height of the bottom surface of the product from the floor, h ｒｅｌ is the height from the bottom of the product of the opening that has a cumulative open area of ​​5 square centimeters from the bottom (excluding holes with dimensions of 0.1 millimeters or less).

7. An air conditioning and hot water supply system as described in any one of claims 1 to 6, comprising a plurality of indoor units, a plurality of the shut-off units being provided for each of the indoor units, and the control unit controlling the shut-off unit in the indoor unit from which the first heat medium has leaked to shut off the first heat medium and to continue supplying the first heat medium to the indoor units other than the indoor unit from which the first heat medium has leaked.

8. The air conditioning and hot water supply system according to any one of claims 1 to 7, wherein the first heat medium is a slightly flammable refrigerant or a flammable refrigerant.

9. The air conditioning and hot water supply system according to any one of claims 1 to 8, wherein the first heat medium is R32.

10. An air conditioning and hot water supply system as claimed in any one of claims 1 to 9, wherein operation of the compressor is stopped when the capacity of the indoor unit with the shutoff unit closed is equal to or greater than a predetermined capacity relative to the capacity of the outdoor unit.

11. A control method for an air conditioning and hot water supply system comprising: an outdoor unit having a compressor that compresses a first heat medium and supplies the first heat medium; a hot water supply unit that generates hot water using the first heat medium supplied from the outdoor unit; an indoor unit that performs air conditioning using the first heat medium supplied from the outdoor unit; and a shutoff unit that shuts off the first heat medium flowing to the indoor unit, wherein when the first heat medium leaks in the indoor unit, the shutoff unit shuts off the first heat medium flowing to the indoor unit, the compressor continues to operate, and the supply of the first heat medium from the outdoor unit to the hot water supply unit continues.

12. A control device used in an air conditioning and hot water supply system comprising: an outdoor unit having a compressor that compresses a first heat medium and supplies the first heat medium; a hot water supply unit that generates hot water using the first heat medium supplied from the outdoor unit; an indoor unit that performs air conditioning using the first heat medium supplied from the outdoor unit; and a shutoff unit that shuts off the first heat medium flowing to the indoor unit, wherein when the first heat medium leaks in the indoor unit, the shutoff unit shuts off the first heat medium flowing to the indoor unit, and controls the compressor to continue operating and to continue the supply of the first heat medium from the outdoor unit to the hot water supply unit.

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