Air conditioner

Abstract

To provide an air conditioner which can inform a user of refrigerant leakage even in a time period before a countermeasure device is actuated.SOLUTION: A control unit (AC) of an air conditioner causes an informing part (71) to provide predetermined information when a detection valve of a refrigerant sensor (45) exceeds a first value and causes countermeasure devices (50, 55, 60) to operate when the detection value of the refrigerant sensor (45) exceeds a second value larger than the first value.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to an air conditioning apparatus. [Background technology]

[0002] Patent Document 1 discloses an air conditioner equipped with a shutoff valve as a countermeasure device. The shutoff valve is provided in the refrigerant piping of the air conditioner. When refrigerant leaks in the target space, a refrigerant sensor detects the refrigerant leakage. The shutoff valve closes accordingly. This makes it possible to suppress the leakage of refrigerant in the target space. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-9267 A Summary of the Invention [Problem to be solved by the invention]

[0004] In air conditioners such as those described in Patent Document 1, the refrigerant may slowly leak into the target space. In such cases, even if the refrigerant is leaking into the target space, the countermeasure device will not operate unless the refrigerant concentration in the target space becomes high to a certain extent. For this reason, even if the refrigerant is leaking, the manager or the like may not be aware of the refrigerant leakage. [Means for solving the problem]

[0005] An air conditioning apparatus according to a first aspect of the present invention comprises: The system includes a utilization unit (30), a refrigerant sensor (45) that detects a refrigerant concentration in a target space (S) that is air-conditioned by the utilization unit (30), a countermeasure device (50, 55, 60) for refrigerant leakage in the target space (S), and a controller (AC) that controls the countermeasure device (50, 55, 60). The controller (AC) determines the presence or absence of refrigerant leakage based on operation data of the air conditioner for a first period from a predetermined time before a point in time when a detection value of the refrigerant sensor (45) exceeds a first value to a predetermined time after the point in time, or for a second period in a predetermined time after the point in time.

[0006] An air conditioning apparatus according to a second aspect includes a notification unit (71), The control unit (AC) causes the notification unit (71) to issue a predetermined information when the detection value of the refrigerant sensor (45) exceeds a first value, and activates the countermeasure device (50, 55, 60) when the detection value of the refrigerant sensor (45) exceeds a second value that is larger than the first value.

[0007] No. 2 From this viewpoint, when the detection value of the refrigerant sensor (45) exceeds the second value, the control unit (AC) activates the countermeasure device (50, 55, 60). Activation of the countermeasure device (50, 55, 60) can suppress refrigerant leakage. When the detection value of the refrigerant sensor (45) exceeds a first value smaller than the second value, the control unit (AC) causes the notification unit (71) to issue a predetermined information. Because the first value is relatively small, the notification unit (71) issues an alert even if the refrigerant leaks relatively slowly. Therefore, the notification unit (71) can notify a person, such as a manager, of the refrigerant leakage. Therefore, a person can take measures against refrigerant leakage before the countermeasure device (50, 55, 60) is activated.

[0008] No. 3 The air conditioner from the viewpoint of 2 In the air conditioning apparatus from this viewpoint, the control unit (AC) causes the notification unit (71) to issue a first message when the detection value of the refrigerant sensor (45) exceeds the first value, and causes the notification unit (71) to issue a second message different from the first message when the detection value of the refrigerant sensor (45) exceeds a second value.

[0009] No. 3 In this respect, the control section (AC) causes the notification section (71) to issue different information when the detection value of the refrigerant sensor (45) exceeds the first value and when the detection value exceeds the second value.

[0010] No. 4 The air conditioner from the viewpoint of 3 In this respect, the second information includes at least one of information regarding a refrigerant leak, information regarding the countermeasure device (50, 55, 60) being activated, and information regarding the inability to operate the air conditioner.

[0011] No. 4From this viewpoint, when the detection value of the refrigerant sensor (45) exceeds the second value, the notification unit (71) issues at least one of the following second information: information indicating that refrigerant is leaking, information indicating that the countermeasure device (50, 55, 60) is operating, and information indicating that the air conditioning apparatus cannot be operated.

[0012] No. 5 The viewpoints are 1 to 4 4 In any one of the above aspects, the refrigerant sensor (45) detects a refrigerant concentration in the target space (S) of the air-conditioning of the utilization unit (30) while the air conditioning apparatus (10) is stopped. The control unit (AC) causes the notification unit (71) to issue a predetermined information report when a detection value of the refrigerant sensor (45) exceeds a first value while the air conditioning apparatus (10) is stopped. The control unit (AC) activates the countermeasure device (50, 55, 60) when a detection value of the refrigerant sensor (45) exceeds the second value.

[0013] No. 5 According to the second aspect, even when the air conditioner (10) is stopped, the control unit (AC) performs control similar to that of the first aspect. Therefore, even if the refrigerant leaks relatively slowly while the air conditioner (10) is stopped, the notification unit (71) issues a notification to enable a person such as a manager to know of the refrigerant leakage. If the refrigerant concentration in the target space (S) becomes relatively high while the air conditioner (10) is stopped, the countermeasure devices (50, 55, 60) can be activated. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic piping diagram of an air conditioner according to an embodiment. [Diagram 2] FIG. 2 is a schematic diagram of the air conditioning device and the safety device. [Diagram 3] FIG. 3 is a schematic configuration diagram of the air conditioning system. [Figure 4] FIG. 4 is a flowchart showing the operation of the air conditioner when a refrigerant leaks. [Diagram 5]FIG. 5 is a block diagram showing the control unit of the air conditioner according to the first modification and its peripheral configuration. [Figure 6] FIG. 6 is a diagram corresponding to FIG. 4 according to the first modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] <<Embodiment>> Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below, and various modifications are possible within the scope of the technical idea of ​​the present disclosure. Since each drawing is intended to conceptually explain the present disclosure, dimensions, ratios, or numbers may be exaggerated or simplified as necessary for ease of understanding.

[0016] (1) Overall configuration of air conditioning system The air conditioner (10) will be described. Fig. 1 is a piping diagram of the air conditioner (10). Fig. 2 is a schematic configuration diagram showing basic elements of the air conditioner (10). In Fig. 2, the second utilization unit (30B) is not shown.

[0017] The air conditioner (10) adjusts the air temperature in a target space (S) to be air-conditioned. In this example, the target space (S) is an indoor space such as a building. The air conditioner (10) cools and heats the target space (S). The air conditioner (10) is a multi-type having a plurality of utilization units (30). The air conditioner (10) has a heat source unit (20), a plurality of utilization units (30), a communication pipe (12), and a control unit (AC). The plurality of utilization units (30) and the heat source unit (20) are connected to each other via the communication pipe (12). This connection forms a refrigerant circuit (11), which is a closed circuit.

[0018] (2-1) Refrigerant circuit The refrigerant circuit (11) includes a heat source circuit (20a) provided in the heat source unit (20) and a utilization circuit (30a) provided in each of the utilization units (30).

[0019] The refrigerant circuit (11) is filled with a slightly flammable refrigerant. In this example, the slightly flammable refrigerant is R32 (difluoromethane). R32 has a relatively low GWP (Global Warming Potential), but is slightly flammable. Therefore, if the refrigerant leaks into the target space (S) and the refrigerant concentration in the target space (S) increases, the refrigerant may burn. The density of the refrigerant is greater than the density of air. Therefore, if the refrigerant leaks into the target space (S), the refrigerant flows to the lower part of the target space (S).

[0020] (2-2) Connecting piping The interconnecting pipe (12) includes a first interconnecting pipe (13) and a second interconnecting pipe (14).

[0021] The first connection pipe (13) is a liquid connection pipe. The first connection pipe (13) includes a first main pipe (13a) and a plurality of first branch pipes (13b) branching off from the first main pipe (13a). One end of the first main pipe (13a) is connected to the heat source circuit (20a) via a first shut-off valve (15) which is a liquid shut-off valve. One end of each of the plurality of first branch pipes (13b) is connected to the first main pipe (13a). The other end of each of the plurality of first branch pipes (13b) is connected to a corresponding utilization circuit (30a).

[0022] The second connection pipe (14) is a gas connection pipe. The second connection pipe (14) includes a second main pipe (14a) and a plurality of second branch pipes (14b) branching off from the second main pipe (14a). One end of the second main pipe (14a) is connected to the heat source unit (20) via a second shutoff valve (16) which is a gas shutoff valve. One end of each of the plurality of second branch pipes (14b) is connected to the second main pipe (14a). The other end of each of the plurality of second branch pipes (14b) is connected to a corresponding utilization unit (30).

[0023] (2-3) Heat source unit The heat source unit (20) is an outdoor unit that is disposed outdoors, for example, on the roof of a building or on the ground.

[0024] The heat source unit (20) includes a compressor (21), a heat-source heat exchanger (22), and a heat-source fan (23). The heat source unit (20) includes a switching mechanism (24) for switching the flow path of the refrigerant, and a heat-source expansion valve (25).

[0025] The compressor (21) compresses the sucked refrigerant. The compressor (21) discharges the compressed refrigerant. The compressor (21) is a rotary compressor such as a scroll type, a swing piston type, a rolling piston type, or a screw type. The compressor (21) is configured such that the operating frequency (rotation speed) is variable by an inverter device.

[0026] The heat-source heat exchanger (22) is an outdoor heat exchanger. The heat-source heat exchanger (22) is a fin-and-tube air heat exchanger. The heat-source heat exchanger (22) exchanges heat between the refrigerant flowing therethrough and the outdoor air.

[0027] The heat-source fan (23) is disposed outdoors near the heat-source heat exchanger (22). In this embodiment, the heat-source fan (23) is a propeller fan. The heat-source fan (23) transports air passing through the heat-source heat exchanger (22).

[0028] The switching mechanism (24) changes the flow path of the refrigerant circuit (11) so as to switch between a first refrigeration cycle, which is a cooling cycle, and a second refrigeration cycle, which is a heating cycle. The switching mechanism (24) is a four-way switching valve. The switching mechanism (24) has a first port, a second port, a third port, and a fourth port. The first port of the switching mechanism (24) is connected to the discharge portion of the compressor (21). The second port of the switching mechanism (24) is connected to the suction portion of the compressor (21). The third port of the switching mechanism (24) is connected to the second connection pipe (14) via the second stop valve (16). The fourth port of the switching mechanism (24) is connected to the gas end of the heat source heat exchanger (22).

[0029] The switching mechanism (24) is switchable between a first state and a second state. In the first state (shown by a solid line in FIG. 1), the switching mechanism (24) connects the first port to the fourth port and connects the second port to the third port. In the second state (shown by a dashed line in FIG. 1), the switching mechanism (24) connects the first port to the third port and connects the second port to the fourth port.

[0030] The heat source expansion valve (25) reduces the pressure of the refrigerant. The heat source expansion valve (25) is an outdoor expansion valve. The heat source expansion valve (25) is disposed in the heat source circuit (20a) between the first stop valve (15) and the heat source heat exchanger (22). The heat source expansion valve (25) is an electronic expansion valve whose opening is adjustable.

[0031] The heat source unit (20) has a first control device (C1).

[0032] (2-4) Usage unit In this example, the multiple utilization units (30) include a first utilization unit (30A) and a second utilization unit (30B). The number of utilization units (30) may be three or more. The first utilization unit (30A) and the second utilization unit (30B) are basically configured the same. Hereinafter, for convenience, the first utilization unit (30A) and the second utilization unit (30B) may be simply referred to as utilization units (30).

[0033] The utilization unit (30) is an indoor unit installed indoors in a building or the like. Here, "indoor" is intended to include the space behind a ceiling panel. In this example, the utilization unit (30) is of a ceiling-mounted type. Here, "ceiling-mounted type" is intended to include a ceiling-suspended type in which the utilization unit (30) is suspended, and a ceiling-embedded type in which the utilization unit (30) is disposed in an opening in the ceiling surface.

[0034] The utilization unit (30) includes a utilization expansion valve (31), a utilization heat exchanger (32), and a utilization fan (33).

[0035] The utilization expansion valve (31) reduces the pressure of the refrigerant. The utilization expansion valve (31) is an indoor expansion valve. The utilization expansion valve (31) is disposed in a liquid-side flow path of the utilization heat exchanger (32) in the utilization circuit (30a). The utilization expansion valve (31) is an electronic expansion valve whose opening is adjustable.

[0036] The utilization heat exchanger (32) is an indoor heat exchanger. The utilization heat exchanger (32) is a fin-and-tube type air heat exchanger. The utilization heat exchanger (32) exchanges heat between the refrigerant flowing therethrough and the indoor air.

[0037] The utilization fan (33) is disposed indoors near the utilization heat exchanger (32). In this embodiment, the utilization fan (33) is a centrifugal fan. The utilization fan (33) transports air passing through the utilization heat exchanger (32).

[0038] The utilization unit (30) has a second control device (C2). The second control device (C2) of each utilization unit (30) and the first control device (C1) are connected to each other via a first communication line (W1). The first communication line (W1) is wired or wireless.

[0039] (2-5) Remote Controller The air conditioner (10) has a remote controller (40). In this example, one remote controller (40) is provided for each of the corresponding utilization units (30). The remote controller (40) is a device for operating the air conditioner (10). As shown in FIG. 2, the remote controller (40) has a first operation unit (41) and a first display unit (42) as functional units. Note that the term "functional unit" used here or described below includes a functional unit realized only by hardware, a functional unit realized only by software, and a functional unit realized through cooperation between hardware and software.

[0040] The first operation unit (41) is a functional unit that enables a person to input various instructions to the air conditioner (10). The first operation unit (41) includes a switch, a button, or a touch panel.

[0041] The first display section (42) is a functional section that displays settings for the air conditioner (10) and the status of the air conditioner (10). The first display section (42) includes a display.

[0042] The remote controller (40) includes a third control device (C3). The third control device (C3) and the second control device (C2) are connected to each other via a second communication line (W2). The second communication line (W2) is wired or wireless.

[0043] (2-6) The air conditioner (10) is provided with a safety device (5). The safety device (5) includes a refrigerant sensor (45) and a countermeasure device (50, 55, 60). The refrigerant sensor (45) detects refrigerant leakage. The countermeasure device (50, 55, 60) is a device that takes measures against refrigerant leakage. The countermeasure device (50, 55, 60) includes at least one of a shutoff device (50), a ventilation device (55), and an alarm device (60). The safety device (5) in this example is provided corresponding to the first utilization unit (30A). In other words, the safety device (5) is provided corresponding to the first target space (S1). The safety device (5) may be provided corresponding to the second utilization unit (30B) and the second target space (S).

[0044] (2-7) Refrigerant sensor The air conditioner (10) of the example shown in Fig. 1 has a refrigerant sensor (45). The refrigerant sensor (45) is provided corresponding to the target space (S) for which it has been determined that a safety device (5) is required.

[0045] The refrigerant sensor (45) is a semiconductor sensor. The refrigerant sensor (45) outputs a detection signal with a greater intensity (e.g., a current value) as the concentration of the leaked refrigerant increases. The refrigerant sensor (45) is not limited to a semiconductor sensor and may be of another type, such as an infrared sensor.

[0046] The refrigerant sensor (45) and the second control device (C2) of the first utilization unit (30A) are connected to each other by a third communication line (W3). The third communication line (W3) is wired or wireless. A detection signal output from the refrigerant sensor (45) is input to the second control device (C2) via the third communication line (W3).

[0047] (2-8) Circuit breaker The air conditioner (10) has a shutoff device (50) as a countermeasure device. The shutoff device (50) is provided corresponding to the target space (S) for which it has been determined that a safety device (5) is required. In this example, the shutoff device (50) is provided corresponding to the first target space (S1) or the first utilization unit (30A). The shutoff device (50) has a first shutoff valve (51) and a second shutoff valve (52).

[0048] The first shutoff valve (51) is a liquid-side shutoff valve. In this example, the first shutoff valve (51) is provided in the first branch pipe (13b) connected to the first utilization unit (30A). The first shutoff valve (51) is, for example, an on-off valve such as a solenoid valve or a motor-operated valve.

[0049] The second shutoff valve (52) is a gas-side shutoff valve. In this example, the second shutoff valve (52) is provided in the second branch pipe (14b) connected to the first utilization unit (30A). The second shutoff valve (52) is, for example, an on-off valve such as a solenoid valve or a motor-operated valve.

[0050] The cutoff device (50) has a fourth control device (C4). The fourth control device (C4) and the second control device (C2) of the first utilization unit (30A) are connected to each other via a fourth communication line (W4). The fourth communication line (W4) is wired or wireless.

[0051] (2-9) Ventilation equipment The air conditioner (10) has a ventilation device (55) as a countermeasure device. The ventilation device (55) is provided corresponding to the target space (S) for which it has been determined that a safety device (5) is required. In this example, the ventilation device (55) is provided corresponding to the first target space (S1) or the first utilization unit (30A). The shutoff device (50) has a ventilation fan (56). The ventilation fan (56) exhausts air from the target space (S) to the outside via an exhaust path (not shown).

[0052] The ventilation device (55) has a fifth control device (C5). The fifth control device (C5) and the second control device (C2) of the first utilization unit (30A) are connected to each other via a fifth communication line (W5). The fifth communication line (W5) is wired or wireless.

[0053] (2-10) Alarm device The air conditioner (10) has an alarm device (60) as a countermeasure device. The alarm device (60) is provided corresponding to the target space (S) for which it has been determined that a safety device (5) is necessary. In this example, the alarm device (60) is provided corresponding to the first target space (S1) or the first utilization unit (30A). The alarm device (60) has a light-emitting unit (61) and a sound-emitting unit (62) as an alarm. The light-emitting unit (61) notifies a person of a refrigerant leakage by light. The light-emitting unit (61) is, for example, an LED. The sound-emitting unit (62) notifies a person of a refrigerant leakage by sound. The sound-emitting unit (62) is, for example, a speaker.

[0054] The alarm device (60) includes a sixth control device (C6). The sixth control device (C6) and the second control device (C2) of the first utilization unit (30A) are connected to each other via a sixth communication line (W6). The sixth communication line (W6) is wired or wireless.

[0055] (2-11) Alarm device As shown in Fig. 2, the air conditioner (10) includes an alarm device (70). The alarm device (70) is a device that notifies a person (strictly speaking, a manager) of a refrigerant leak. The alarm device (70) includes a seventh control device (C7) and an alarm section (71). The seventh control device (C6) and the second control device (C2) of the first utilization unit (30A) are connected to each other via a seventh communication line (W7). The seventh communication line (W6) is wired or wireless.

[0056] The notification unit (71) issues information indicating that refrigerant has leaked. In this example, the notification unit (71) outputs information indicating that refrigerant has leaked to the centralized monitoring device (65). This allows a manager to know that refrigerant has leaked (details will be described later). The term "issuing an alert" as used herein includes notifications such as email or fax, sound (including voice), and screen display.

[0057] The notification device (70) may be provided in the utilization unit (30) or in the heat source unit (20).

[0058] (2-12) Control section The control unit (AC) controls the operation of the air conditioner (10). The control unit (AC) includes a first control device (C1), a second control device (C2), a third control device (C3), a fourth control device (C4), a fifth control device (C5), a sixth control device (C6), a seventh control device (C7), a first communication line (W1), a second communication line (W2), a third communication line (W3), a fourth communication line (W4), a fifth communication line (W5), a sixth communication line (W6), and a seventh communication line (W7). Each of the first control device (C1), the second control device (C2), the third control device (C3), the fourth control device (C4), the fifth control device (C5), the sixth control device (C6), and the seventh control device (C7) includes an MCU (Micro Control Unit), an electric circuit, and an electronic circuit. The MCU includes a CPU (Central Processing Unit), memory, and a communication interface. The memory stores various programs to be executed by the CPU.

[0059] The first control device (C1) is a heat source control unit. The first control device (C1) controls the compressor (21), the heat source expansion valve (25), and the heat source fan (23).

[0060] The second control device (C2) is a utilization control unit. The second control device (C2) controls the utilization expansion valve (31) and the utilization fan (33). The second control device (C2) receives a detection signal from the refrigerant sensor (45). The second control device (C2) determines whether or not the detection value of the refrigerant sensor (45) exceeds a first value. The second control device (C2) determines whether or not the detection value of the refrigerant sensor (45) exceeds a second value. Here, the detection value of the refrigerant sensor (45) is, for example, an output current value. The detection value of the refrigerant sensor (45) increases depending on the refrigerant concentration around it. The second value is greater than the first value. For example, the first value is several percent of the second value.

[0061] The second control device (C2) activates the notification device (70) when the detection value of the refrigerant sensor (45) exceeds the first value. Specifically, the second control device (C2) outputs a first signal to the notification device (70) when the detection value of the refrigerant sensor (45) exceeds the first value.

[0062] The second control device (C2) activates the countermeasure devices (50, 55, 60) when the detection value of the refrigerant sensor (45) exceeds the second value. Specifically, the second control device (C2) outputs a second signal to the countermeasure devices (50, 55, 60) when the detection value of the refrigerant sensor (45) exceeds the second value. In addition, the second control device (C2) outputs a third signal to the alarm device (70) when the detection value of the refrigerant sensor (45) exceeds the second value.

[0063] The third control device (C3) outputs to the second control device (C2) an instruction based on an input from the first operation unit (41). The third control device (C3) causes the first display unit (42) to display predetermined information in response to the input from the first operation unit (41).

[0064] The fourth control device (C4) controls the open / closed states of the first shutoff valve (51) and the second shutoff valve (52). When the second signal output from the second control device (C2) is input to the fourth control device (C4), the fourth control device (C4) closes the first shutoff valve (51) and the second shutoff valve (52).

[0065] The fifth control device (C5) controls the ventilation fan (56). When the second signal output from the second control device (C2) is input to the fifth control device (C5), the fifth control device (C5) operates the ventilation fan (56).

[0066] The sixth control device (C6) controls the alarm device (60). When the second signal output from the second control device (C2) is input to the sixth control device (C6), the sixth control device (C6) activates the light emitting unit (61) and the sound generating unit (62).

[0067] The seventh control device (C7) controls the notification unit (71). When the first signal output from the second control device (C2) is input to the seventh control device (C7), the seventh control device (C7) causes the notification unit (71) to issue a first information. When the third signal output from the second control device (C2) is input to the seventh control device (C7), the seventh control device (C7) causes the notification unit (71) to issue a second information different from the first information.

[0068] The first information includes information about refrigerant leakage. The second information includes information about refrigerant leakage, information about the operation of the countermeasure devices (50, 55, 60), and information about the inoperability of the air conditioner (10). The degree of the refrigerant leakage level for the information about refrigerant leakage in the first information is lower than the degree of the refrigerant leakage level for the information about refrigerant leakage in the second information.

[0069] (2-13) Sensor As shown in Fig. 1, the air conditioner (10) includes a plurality of sensors, including a high pressure sensor (90), a low pressure sensor (91), a discharge temperature sensor (92), a suction temperature sensor (93), a first refrigerant temperature sensor (94), a second refrigerant temperature sensor (95), a third refrigerant temperature sensor (96), an outside air temperature sensor (97), and a suction temperature sensor (98).

[0070] The high-pressure pressure sensor (90) detects the pressure of the high-pressure refrigerant (discharge refrigerant) discharged from the compressor (21). The low-pressure pressure sensor (91) detects the pressure of the low-pressure refrigerant (suction refrigerant) sucked into the compressor (21). The discharge temperature sensor (92) detects the temperature of the high-pressure refrigerant discharged from the compressor (21). The first refrigerant temperature sensor (94) detects the temperature of the refrigerant at the liquid side end of the heat-source heat exchanger (22). The second refrigerant temperature sensor (95) detects the temperature of the refrigerant at the liquid side end of the utilization heat exchanger (32). The third refrigerant temperature sensor (96) detects the temperature of the refrigerant at the gas side end of the utilization heat exchanger (32). The outdoor air temperature sensor (97) detects the temperature of outdoor air. The suction temperature sensor (98) detects the temperature of indoor air blown into the utilization unit (30).

[0071] (3) Air conditioning system As shown in Fig. 3, the air conditioner (10) described above is a single-system device having one refrigerant circuit (11). In a building or the like, an air conditioning system (1) is configured that includes multiple systems of air conditioners (10). The air conditioning system (1) has multiple air conditioners (10) and a centralized monitoring device (65).

[0072] The centralized monitoring device (65) has, as its functional parts, a second operation part (66) and a second display part (67).

[0073] The second operation unit (66) is a functional unit that enables a person (such as a manager) to input various instructions to each air conditioner (10). The second operation unit (66) includes a switch, a button, or a touch panel.

[0074] The second display section (67) is a functional section that displays the settings for each air conditioner (10) and the status of each air conditioner (10). The second display section (67) includes a display.

[0075] The centralized monitoring device (65) has an eighth control device (C8). The eighth control device (C8) and the control units (AC) of the air conditioners (10) are connected to each other via an eighth communication line (W8). The eighth communication line (W8) is wired or wireless.

[0076] The eighth control device (C8) includes an MCU (Micro Control Unit), an electric circuit, and an electronic circuit. The MCU includes a CPU (Central Processing Unit), a memory, and a communication interface. The memory stores various programs for the CPU to execute.

[0077] The information of the notification unit (71) is input to the centralized monitoring device (65) via the eighth communication line (W8). When the centralized monitoring device (65) receives the notification, the information from the notification unit (71) is displayed on the second display unit (67). Specifically, when the first information is input to the centralized monitoring device (65), the second display unit (67) displays, for example, information about refrigerant leakage (low level). When the second information is input to the centralized monitoring device (65), the second display unit (67) displays, for example, at least one of information about refrigerant leakage (high level), information about the operation of the countermeasure devices (50, 55, 60), and information about the inoperability of the air conditioner (10). The displayed information includes characters, symbols, icons, figures, and the like. The centralized monitoring device (65) may inform the manager of the information by voice.

[0078] (4) Driving behavior The operation of the air conditioner (10) will be described with reference to Fig. 1. The air conditioner (10) switches between cooling operation and heating operation. In Fig. 1, the flow of refrigerant during cooling operation is indicated by solid arrows, and the flow of refrigerant during heating operation is indicated by dashed arrows.

[0079] (4-1) Cooling operation In the cooling operation, the first control device (C1) operates the compressor (21) and the heat-source fan (23), sets the switching mechanism (24) to the first state, and fully opens the heat-source expansion valve (25). The second control device (C2) operates the utility fan (33) and adjusts the utility expansion valve (31) to a predetermined opening. During normal cooling operation, the first shutoff valve (51) and the second shutoff valve (52) are open.

[0080] In the cooling operation, the refrigerant circuit (11) performs a first refrigeration cycle. In the first refrigeration cycle, the heat source heat exchanger (22) functions as a radiator (strictly speaking, a condenser), and the utilization heat exchanger (32) functions as an evaporator.

[0081] Specifically, the refrigerant compressed by the compressor (21) flows through the heat source heat exchanger (22). In the heat source heat exchanger (22), the refrigerant releases heat to the outdoor air and condenses. The refrigerant condensed in the heat source heat exchanger (22) flows through the first interconnecting pipe (13) and is divided into each utilization circuit (30a). In each utilization circuit (30a), the refrigerant is reduced in pressure by the utilization expansion valve (31) and then flows through the utilization heat exchanger (32). In the utilization heat exchanger (32), the refrigerant absorbs heat from the indoor air and evaporates. The refrigerant evaporated in each utilization heat exchanger (32) joins together in the second interconnecting pipe (14) and is then drawn into the compressor (21).

[0082] (4-2) Heating operation In the heating operation, the first control device (C1) operates the compressor (21) and the heat-source fan (23), sets the switching mechanism (24) to the second state, and adjusts the heat-source expansion valve (25) to a predetermined opening. The second control device (C2) operates the utility fan (33) and adjusts the utility expansion valve (31) to a predetermined opening. During normal heating operation, the first shutoff valve (51) and the second shutoff valve (52) are open.

[0083] In the heating operation, the refrigerant circuit (11) performs a second refrigeration cycle. In the second refrigeration cycle, the utilization heat exchanger (32) functions as a radiator (strictly speaking, a condenser), and the heat source heat exchanger (22) functions as an evaporator.

[0084] Specifically, the refrigerant compressed by the compressor (21) flows through the second interconnection pipe (14) and is divided into each utilization circuit (30a). In each utilization circuit (30a), the refrigerant flows through the utilization heat exchanger (32). In the utilization heat exchanger (32), the refrigerant dissipates heat to the indoor air and condenses. The refrigerant condensed in each utilization heat exchanger (32) is reduced in pressure by each utilization expansion valve (31) and then merges in the first interconnection pipe (13). The refrigerant in the first interconnection pipe (13) is reduced in pressure by the heat source expansion valve (25) and then flows through the heat source heat exchanger (22). In the heat source heat exchanger (22), the refrigerant absorbs heat from the outdoor air and evaporates. The refrigerant evaporated in the heat source heat exchanger (22) is sucked into the compressor (21).

[0085] (5) Operation in the event of a refrigerant leak The operation of the air conditioner (10) when a refrigerant leaks will be described with reference to Figure 4. The following operation is performed while the air conditioner (10) is in operation.

[0086] When the refrigerant leaks from the first usage unit (30A), the leaked refrigerant flows into the first target space (S1). Specifically, since the density of the refrigerant is greater than the density of air, the refrigerant flows downward in the first target space (S1). As a result, the concentration of the refrigerant in the first target space (S1) gradually increases.

[0087] In step S11, the refrigerant sensor (45) detects a refrigerant leak. A detection value of the refrigerant sensor (45) is input to the second control device (C2) of the first utilization unit (30A) via the third communication line (W3).

[0088] In step S12, the second control device (C2) determines whether the detection value of the refrigerant sensor (45) exceeds a first value. If the detection value of the refrigerant sensor (45) exceeds the first value, in step S13, the second control device (C2) outputs a first signal to the seventh control device (C7). In step S13, the seventh control device (C7) causes the notification unit (71) to issue an alarm. Specifically, the notification unit (71) outputs the first information to the centralized monitoring device (65).

[0089] The second display unit (67) of the centralized monitoring device (65) displays the first information. Specifically, the second display unit (67) displays, as the first information, "refrigerant has started to leak," "refrigerant is leaking slowly," "some measure is needed to deal with the refrigerant leakage," etc. This enables the manager to take some kind of measure while the level of refrigerant leakage is still low.

[0090] In step S14, the second control device (C2) determines whether or not the detection value of the refrigerant sensor (45) exceeds the second value. If the detection value of the refrigerant sensor (45) exceeds the second value, in step S15, the second control device (C2) outputs a second signal for activating the countermeasure devices (50, 55, 60). In step S15, the countermeasure devices (50, 55, 60) are activated. Specifically, in step S15, when the second signal output from the second control device (C2) is input to the fourth control device (C4), the fourth control device (C4) closes the first shutoff valve (51) and the second shutoff valve (52) of the shutoff device (50). In step S15, when the second signal output from the second control device (C2) is input to the fifth control device (C5), the fifth control device (C5) operates the ventilation fan (56). In step S15, when the second signal output from the second control device (C2) is input to the sixth control device (C6), the sixth control device (C6) causes the light emitting unit (61) to emit light and also causes the sound generating unit (62) to emit a sound such as a warning sound.

[0091] In this manner, by activating the countermeasure device (50, 55, 60), it is possible to reliably suppress refrigerant leakage when countermeasures against refrigerant leakage based on the first information cannot be taken in time.

[0092] When the detection value of the refrigerant sensor (45) exceeds the second value in step S14, the second control device (C2) outputs a second signal to the seventh control device (C7) in step S16. In step S16, the seventh control device (C7) causes the notification unit (71) to issue a notification. Specifically, the notification unit (71) outputs the second information to the centralized monitoring device (65).

[0093] The second display unit (67) of the centralized monitoring device (65) displays the second information. Specifically, the second display unit (67) displays, as the second information, "There is a considerable leakage of refrigerant," "There is a sudden leakage of refrigerant," "A countermeasure device has been activated due to the refrigerant leakage," "The air conditioner (10) cannot be operated due to the refrigerant leakage," and the like. This enables the manager to know when the level of refrigerant leakage is high, and to take appropriate measures.

[0094] (6) Features (6-1) The air conditioning system (10) includes a countermeasure device (50, 55, 60) for refrigerant leakage in the target space (S), an alarm unit (71), and a control unit (AC) that controls the countermeasure device (50, 55, 60) and the alarm unit (71). The control unit (AC) causes the alarm unit (71) to issue a predetermined information when a detection value of the refrigerant sensor (45) exceeds a first value. The control unit (AC) activates the countermeasure device (50, 55, 60) when a detection value of the refrigerant sensor (45) exceeds a second value that is larger than the first value.

[0095] As a result, even if the refrigerant leakage is slow and the refrigerant concentration in the target space (S) is relatively low, the manager or the like can quickly become aware of this by the alarm from the alarm unit (71), and can therefore take some kind of measures before the level of refrigerant leakage becomes large.

[0096] When the refrigerant concentration in the target space (S) reaches a relatively high level, the countermeasure devices (50, 55, 60) are activated. Therefore, even if the manager or other person is unable to take countermeasures in time, the countermeasure devices (50, 55, 60) reliably suppress refrigerant leakage. Therefore, sufficient safety measures can be taken for the target space (S).

[0097] (6-2) The notification unit (71) issues a first message when the detection value of the refrigerant sensor (45) exceeds a first value, and issues a second message different from the first message when the detection value of the refrigerant sensor (45) exceeds a second value. This enables a manager or the like to know necessary information depending on the level of the refrigerant concentration in the target space (S).

[0098] Specifically, when the detection value of the refrigerant sensor (45) exceeds a first value, the notification unit (71) issues first information indicating that a low-level refrigerant leakage has occurred. When the detection value of the refrigerant sensor (45) exceeds a second value, the notification unit (71) issues second information indicating that a high-level refrigerant leakage has occurred. This enables the manager to take appropriate measures depending on the level of the refrigerant leakage.

[0099] (6-3) The second information includes at least one of information indicating that refrigerant is leaking, information indicating that the countermeasure device (50, 55, 60) is operating, and information indicating that the air conditioner (10) cannot be operated.

[0100] Therefore, when the refrigerant concentration in the target space (S) is at a relatively high level, the manager can quickly know that refrigerant is leaking, that the countermeasure device (50, 55, 60) is operating, or that the air conditioning apparatus (10) is unable to operate.

[0101] (7) Variations The above embodiment may be modified as follows. The following describes the differences from the embodiment.

[0102] (7-1) Variation 1 The air conditioner (10) according to the first modification acquires information related to refrigerant leakage based on its operating data. As shown in FIG. 5, the control unit (AC) of the air conditioner (10) according to the first modification includes a memory unit (81) and an information acquisition unit (82) as a functional unit. In this example, the memory unit (81) and the information acquisition unit (82) are provided in the first control device (C1) of the heat source unit (20). The memory unit (81) and the information acquisition unit (82) may be provided in the second control device (C2) of the utilization unit (30).

[0103] The storage unit (81) includes a hard disk drive (HDD), a random access memory (RAM), a solid state drive (SSD), etc. The storage unit (81) stores the detection values ​​of the above-mentioned sensors (90-97) as operation data. In addition, the storage unit (81) stores control parameters such as the rotation speed (operating frequency) of the compressor (21), the opening of the utility expansion valve (31), the opening of the heat-source expansion valve (25), the target evaporation temperature, the target condensation temperature, the indoor temperature setting, the air volume of the heat-source fan (23), and the air volume of the utility fan (33), as operation data of the air conditioner (10).

[0104] The information acquiring unit (82) acquires information on refrigerant leakage based on the operating data stored in the storage unit (81). Specifically, the information acquiring unit (82) in this example identifies the location of refrigerant leakage based on the operating data.

[0105] For example, if the pressure detected by the high-pressure pressure sensor (90) drops suddenly compared to the pressure detected by the low-pressure pressure sensor (91), it can be determined that refrigerant has leaked from the high-pressure line of the refrigerant circuit (11). Alternatively, if the pressure detected by the low-pressure pressure sensor (91) drops suddenly compared to the pressure detected by the high-pressure pressure sensor (90), it can be determined that refrigerant has leaked from the low-pressure line of the refrigerant circuit (11). Furthermore, by providing pressure sensors for the first connecting pipe (13), which is a liquid pipe, and the second connecting pipe (14), which is a gas pipe, it is possible to identify refrigerant leakage from these connecting pipes (13, 14). Furthermore, by estimating theoretical amounts of refrigerant in the high-pressure line, the low-pressure line, the connecting pipe (12), etc. from the detection values ​​of the various sensors (90-97) and determining a decrease in these refrigerant amounts, it is possible to identify the location of the refrigerant leakage. In this case, the theoretical amount of refrigerant for each specified portion of the refrigerant circuit (11) can be estimated based on the internal volumes of the utilization heat exchanger (32), the heat source heat exchanger (22), the connecting pipe (12), etc., and the density of the refrigerant flowing therethrough.

[0106] The operation of the air conditioner (10) of the first modification will be described with reference to FIG.

[0107] In step S21, the storage unit (81) of the information acquisition unit (82) stores the detection values ​​of the sensors (90-97) and control parameters as operating data. The storage unit (81) stores the operating data at predetermined time intervals. In step S22, the refrigerant sensor (45) detects a refrigerant leak.

[0108] In step S23, the control unit (AC) determines whether the detection value of the refrigerant sensor (45) exceeds a first value. If the detection value of the refrigerant sensor (45) exceeds the first value, in step S24, the information acquisition unit (82) acquires information on refrigerant leakage based on the operating data stored in the memory unit (81) in synchronization with the detection value exceeding the first value.

[0109] Here, the operating data referred to by the information acquisition unit (82) in this example is data for a predetermined first period including time t1 when the detection value of the refrigerant sensor (45) exceeds a first value. The start point of the first period is a time point a predetermined time before time t1. The end point of the first period is a time point a predetermined time after time t1. When the detection value of the refrigerant sensor (45) exceeds the first value, an indication of refrigerant leakage also appears in the operating data. Therefore, in the first modification, the information acquisition unit (82) acquires information regarding refrigerant leakage based on the operating data for the first period.

[0110] The information about the refrigerant leakage includes a location of the refrigerant leakage identified based on the operating data. That is, in step S24, the information acquisition unit (82) identifies the location of the refrigerant leakage based on the operating data for the first time period.

[0111] In step S25, the notification unit (71) issues the first information and the third information. Here, the third information includes the location of the refrigerant leakage. The notification unit (71) outputs the first information and the third information to the centralized monitoring device (65).

[0112] The second display unit (67) of the centralized monitoring device (65) displays third information in addition to the first information. Specifically, the second display unit (67) displays the location of the refrigerant leakage identified based on the operating data. Therefore, the manager can not only know that the refrigerant is leaking from the refrigerant sensor (45), but also know the location in the refrigerant circuit (11) where the refrigerant is leaking.

[0113] Steps S26 to S28 according to the first modification are the same as steps S14 to S16 according to the embodiment.

[0114] As described above, in the first modification, when the detection value of the refrigerant sensor (45) exceeds the first value, the notification unit (71) issues the first information to notify of a refrigerant leak. The accuracy of detecting a refrigerant leak by the refrigerant sensor (45) is higher than the accuracy of determining a refrigerant leak based on the operating data. Therefore, even if a refrigerant leaks slowly into the target space (S), the manager or the like can be reliably notified of the refrigerant leak.

[0115] On the other hand, the detection of refrigerant leakage by the refrigerant sensor (45) alone is not enough to identify the part of the refrigerant circuit (11) where the refrigerant is leaking. In contrast, in the first modification, the information acquisition unit (82) acquires information about the refrigerant leakage based on the operating data (more precisely, information about the location of the refrigerant leakage) in synchronization with the detection value of the refrigerant sensor (45) exceeding the first value. Therefore, based on the data acquired by the information acquisition unit (82), a manager or the like can determine the part of the refrigerant circuit (11) where the refrigerant is leaking.

[0116] More specifically, the notification unit (71) issues third information that identifies the location of the refrigerant leakage, in addition to the first information, so that the worker can reliably know not only that there is a refrigerant leakage, but also the location of the refrigerant leakage.

[0117] (7-1-1) Other form 1 of modification 1 The information acquiring unit (82) may identify the location of the refrigerant leakage after the notification unit (71) issues the first information. In this case, the notification unit (71) issues the third information promptly after the location of the refrigerant leakage is identified.

[0118] (7-1-2) Alternative form 2 of variant 1 The notification section (71) may notify the operating data for the first period itself, so that the manager can determine for himself or herself the location of the refrigerant leakage by referring to the operating data for the first period.

[0119] (7-1-3) Other forms of modification 1 3 The information acquiring unit (82) of the first modification acquires information about refrigerant leakage based on operating data for a first period including time t1 when the detection value of the refrigerant sensor (45) exceeded the first value. However, the information acquiring unit (82) may acquire information about refrigerant leakage based on operating data for a second period from time t1 when the detection value of the refrigerant sensor (45) exceeded the first value until a predetermined time has elapsed. The notification unit (71) notifies the first information and the third information after the second period has elapsed.

[0120] (7-1-4) Other form 4 of variant 1 The information on refrigerant leakage acquired by the information acquisition unit (82) may include a determination result as to whether or not refrigerant is leaking, based on the operating data. The notification unit (71) notifies the determination result as fourth information, so that a manager or the like can be notified of refrigerant leakage with greater accuracy. The information acquisition unit (82) determines whether or not refrigerant is leaking, based on the operating data, by, for example, the following method.

[0121] A) Decrease in high pressure or low pressure of the refrigeration cycle When refrigerant leaks from the refrigerant circuit (11), the high-pressure pressure and the low-pressure pressure decrease. Therefore, the information acquisition unit (82) determines whether or not refrigerant is leaking based on the high-pressure pressure detected by the high-pressure pressure sensor (90) and the low-pressure pressure detected by the low-pressure pressure sensor (91).

[0122] B) Increase in discharge temperature When the refrigerant circuit (11) leaks refrigerant and runs out of gas, the temperature of the refrigerant discharged from the compressor (21) increases rapidly. Therefore, the information acquiring unit (82) determines whether or not the refrigerant is leaking based on the temperature of the discharged refrigerant detected by the discharge temperature sensor (92).

[0123] C) Increase in intake superheat When the refrigerant circuit (11) leaks and runs out of gas, the suction superheat of the refrigerant sucked into the compressor (21) increases rapidly. The information acquisition unit (82) determines whether or not the refrigerant is leaking based on the suction superheat. Here, the suction superheat can be obtained, for example, from the difference between the temperature of the suction refrigerant detected by the suction temperature sensor (93) and the saturation temperature corresponding to the low pressure detected by the low pressure sensor (91).

[0124] D) Decrease in degree of supercooling When the refrigerant in the refrigerant circuit (11) leaks and becomes a gas state, the degree of subcooling of the condenser (heat radiator) drops sharply. Therefore, the information acquisition unit (82) determines whether or not the refrigerant is leaking based on the degree of subcooling. Here, for example, the degree of subcooling can be obtained from the difference between the saturation temperature corresponding to the high pressure detected by the high pressure sensor (90) and the refrigerant temperature at the outlet of the heat exchanger serving as the condenser. Here, the refrigerant temperature at the outlet of the heat exchanger serving as the condenser is the temperature detected by the first refrigerant temperature sensor (94) in the cooling operation, or the temperature detected by the second refrigerant temperature sensor (95) in the heating operation.

[0125] E) Reduction in the temperature difference between the air before and after passing through the heat exchanger When the refrigerant in the refrigerant circuit (11) leaks and becomes gaseous, the temperature difference between the air before and after passing through the heat exchanger becomes small. Therefore, the information acquisition unit (82) determines whether or not the refrigerant is leaking based on the air temperature difference. Here, for example, in the utilization unit (30), a discharge temperature sensor is provided in addition to the suction temperature sensor (98). The discharge temperature sensor detects the temperature of the air that has passed through the utilization heat exchanger (32). The air temperature difference can be obtained from the difference between the temperatures detected by the suction temperature sensor (98) and the discharge temperature sensor.

[0126] The information acquiring section (82) similarly determines that refrigerant is leaking when the temperature difference between the air before and after the heat-source heat exchanger (22) becomes small.

[0127] The information acquiring unit (82) determines whether or not there is a refrigerant leak by using at least one of the above methods A) to E), or a combination of two or more of these methods.

[0128] (7-1-5) Other forms of modification 1 5 The information acquiring unit (82) may acquire information about refrigerant leakage (the third information and the fourth information described above) based on the operating data in synchronization with the detection value of the refrigerant sensor (45) exceeding the second value. In this case, the notification unit (71) issues the third information and the fourth information in addition to the second information. In this case, a manager or the like can learn the location of the refrigerant leakage at the time when the countermeasure device (50, 55, 60) is activated.

[0129] (7-2) Variation 2 The air conditioner (10) of the above embodiment performs the operation shown in Fig. 4 during operation. However, the air conditioner (10) may also perform the operation shown in Fig. 4 during a stop in which neither cooling nor heating operation is being performed.

[0130] Specifically, the refrigerant sensor (45) detects a refrigerant concentration in the target space (S) of the air conditioned by the utilization unit (30) while the air conditioning apparatus (10) is stopped. When a value detected by the refrigerant sensor (45) exceeds a first value while the air conditioning apparatus (10) is stopped, the control unit (AC) causes the notification unit (71) to issue a predetermined information. When a value detected by the refrigerant sensor (45) exceeds a second value, the control unit (AC) activates the countermeasure devices (50, 55, 60).

[0131] As a result, even if the refrigerant slowly leaks while the air conditioner (10) is stopped, the fact can be quickly notified to a manager, etc. Even if the refrigerant concentration in the target space (S) becomes relatively high while the air conditioner (10) is stopped, the countermeasure device (50, 55, 60) can quickly suppress the leakage of the refrigerant.

[0132] (7-3) Variation 3 The notification unit (71) in the embodiment issues predetermined information to the centralized monitoring device (65). However, the notification unit (71) may also issue a notification to a location (e.g., a management center) other than the location (e.g., a building) where the air conditioning apparatus (10) is installed. In this case, the notification unit (71) notifies the administrator of the management center of the predetermined information by, for example, email, fax, or voice telephone call.

[0133] (7-4) Variation 4 The air conditioning apparatus (10) of the embodiment has, as the countermeasure devices, a shutoff device (50), a ventilation device (55), and an alarm device (60). However, the air conditioning apparatus (10) may have, as the countermeasure devices, any two of the shutoff device (50), the ventilation device (55), and the alarm device (60), or any one of them.

[0134] Other Embodiments In the above-described embodiment and its modified examples, the following configurations may be adopted.

[0135] 1) The air conditioner (10) does not have to be a multi-type, and may be a pair-type having one utilization unit (30) and one heat source unit (20). The air conditioner (10) may have a plurality of heat source units (20).

[0136] 2) The refrigerant filled in the refrigerant circuit (11) may be a refrigerant other than R32. The refrigerant includes refrigerants that fall under Class 3 (highly flammable), Class 2 (lowly flammable), or Subclass 2L (slightly flammable) in the U.S. ASHRAE34 Designation and Safety Classification of Refrigerants standard or the ISO817 Refrigerants- Designation and Safety Classification standard.

[0137] For example, the refrigerant may be a single refrigerant selected from the group consisting of R1234yf, R1234ze(E), R516A, R445A, R444A, R454C, R444B, R454A, R455A, R457A, R459B, R452B, R454B, R447B, R32, R447A, R446A, and R459.

[0138] Alternatively, the refrigerant is a mixed refrigerant consisting of two or more refrigerants selected from R1234yf, R1234ze(E), R516A, R445A, R444A, R454C, R444B, R454A, R455A, R457A, R459B, R452B, R454B, R447B, R32, R447A, R446A, and R459.

[0139] 3) The switching mechanism (24) does not have to be a four-way switching valve. The switching mechanism (24) may be configured by combining four flow paths and on-off valves that open and close the paths, or by combining two three-way valves.

[0140] 4) The heat source expansion valve (25) and the utilization expansion valve (31) do not have to be electronic expansion valves, and may be temperature-sensitive expansion valves or rotary expansion mechanisms.

[0141] 5) The utilization unit (30) does not have to be a ceiling-mounted type, but may be a wall-mounted type or a floor-standing type.

[0142] Although the embodiments and modifications have been described above, it will be understood that various modifications of form and details are possible without departing from the spirit and scope of the claims. Furthermore, the above embodiments, modifications, and other embodiments may be appropriately combined or substituted as long as the functions of the subject of the present disclosure are not impaired.

[0143] The descriptions "first," "second," "third," etc. mentioned above are used to distinguish the words to which these descriptions are attached, and do not limit the number or order of the words. [Industrial Applicability]

[0144] INDUSTRIAL APPLICABILITY As described above, the present disclosure is useful for air conditioning apparatuses. [Explanation of symbols]

[0145] 10. Air conditioning equipment 30 Usage Units 45 Refrigerant Sensor 50 Circuit Breaker (Countermeasure Device) 55 Ventilation equipment (countermeasure equipment) 60 Alarm device (countermeasure device) 71 Notification Department AC control section

Claims

1. A utilization unit (30); a refrigerant sensor (45) for detecting a refrigerant concentration in a space (S) that is a target space for air conditioning of the utilization unit (30); A countermeasure device (50, 55, 60) for preventing refrigerant leakage from the target space (S); The Information Department (71) and a control unit (AC) that controls the countermeasure device (50, 55, 60) and the notification unit (71), The control unit (AC) causes the notification unit (71) to issue a predetermined information when the detection value of the refrigerant sensor (45) exceeds a first value, and activates the countermeasure device (50, 55, 60) when the detection value of the refrigerant sensor (45) exceeds a second value that is greater than the first value.

2. The control unit (AC) causes the notification unit (71) to issue a first message when the detection value of the refrigerant sensor (45) exceeds the first value, and causes the notification unit (71) to issue a second message different from the first message when the detection value of the refrigerant sensor (45) exceeds a second value. The air conditioning apparatus according to claim 1.

3. The second information includes at least one of information indicating that refrigerant is leaking, information indicating that the countermeasure device (50, 55, 60) is operating, and information indicating that the air conditioner (10) is inoperable. The air conditioning apparatus according to claim 2.

4. The refrigerant sensor (45) detects a refrigerant concentration in a target space (S) of air conditioning of the utilization unit (30) while the air conditioner (10) is stopped; The control unit (AC) causes the notification unit (71) to issue a predetermined information when the detection value of the refrigerant sensor (45) exceeds a first value while the air conditioner (10) is stopped, and causes the countermeasure device (50, 55, 60) to operate when the detection value of the refrigerant sensor (45) exceeds the second value. An air conditioner according to any one of claims 1 to 3.

5. The control unit (AC) acquires information regarding refrigerant leakage based on operation data of the air conditioner (10) in synchronization with the detection value of the refrigerant sensor (45) exceeding the first value. An air conditioner according to any one of claims 1 to 4.

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