Refrigeration System

Abstract

To provide a refrigeration system for enabling quicker transmission of abnormality.SOLUTION: A refrigeration system 10 includes a first device 20, a second device 30 connected to the first device 20 via a first wire 60 and a second wire 70 in a communicative manner, and a refrigerant pipe 50 for circulating refrigerant in the first device 20 or the second device 30, the first device 20 having a first circuit 231 for short-circuiting the first wire 60 and the second wire 70 when abnormality regarding the leakage of the refrigerant is detected, the second device 30 having a second circuit 332 for starting the operation of protection from the abnormality when the first wire 60 and the second wire 70 are short-circuited.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to refrigeration systems. [Background technology]

[0002] 2. Description of the Related Art A refrigeration system that has an indoor unit and an outdoor unit and performs air conditioning or refrigeration by performing heat exchange using a refrigerant is known. In the refrigeration system, a protective operation needs to be performed when the refrigerant leaks outside the refrigeration system.

[0003] For example, in Patent Document 1, the presence or absence of a refrigerant leak is determined based on the measurement value of a refrigerant detection device installed in the indoor unit. If a refrigerant leak is determined to exist, the rotation speed of the indoor blower is controlled to a speed higher than the maximum rotation speed during normal operation, and the operation of the compressor installed in the outdoor unit is stopped. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 175300 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventionally, an indoor control device that controls an indoor unit and an outdoor control device that controls an outdoor unit are connected by a transmission line (communication line) to enable the transmission and reception of information. Therefore, conventionally, when an abnormality occurred in the indoor unit, the abnormality in the indoor unit was transmitted to the outdoor control device via the transmission line, thereby stopping the compressor and other devices mounted on the outdoor unit.

[0006] In order to improve the safety of a refrigeration system that includes multiple devices (e.g., an indoor unit and an outdoor unit), after an abnormality is detected in a first device (e.g., an indoor unit), it is necessary to quickly transmit the abnormality to a second device (e.g., an outdoor unit) that is different from the first device.

[0007] The present disclosure aims to provide a refrigeration system that is capable of communicating abnormalities more quickly. [Means for solving the problem]

[0008] (1) A refrigeration system disclosed herein includes a first device, a second device communicatively connected to the first device via a first electric wire and a second electric wire, and a refrigerant piping that circulates refrigerant through the first device or the second device, wherein the first device has a first circuit that short-circuits the first electric wire and the second electric wire when an abnormality related to refrigerant leakage is detected, and the second device has a second circuit that initiates a protective operation against the abnormality when the first electric wire and the second electric wire are short-circuited.

[0009] According to the refrigeration system of the present disclosure, by shorting the first electric wire and the second electric wire used for communication between the first device and the second device, the abnormality detected by the first device can be transmitted to the second device more quickly, thereby hastening the start of protective action against the abnormality.

[0010] (2) Preferably, the first circuit includes an abnormality detection circuit that detects an abnormality related to refrigerant leakage, and a short-circuit that includes a switch connected in parallel to the first electric wire and the second electric wire, and switches the switch from an open state to a connected state when the abnormality detection circuit detects an abnormality related to refrigerant leakage.

[0011] (3) Preferably, the abnormality detection circuit detects an abnormality based on a detection signal from a sensor that detects a refrigerant leak.

[0012] (4) Preferably, the second circuit includes a short circuit detection circuit that detects a short circuit between the first electric wire and the second electric wire, and a control circuit electrically connected to an operating unit that performs protective operation against abnormalities and that controls the operating unit when a short circuit between the first electric wire and the second electric wire is detected by the short circuit detection circuit, and the second circuit is composed only of hardware.

[0013] By configuring the second circuit, which starts the protective operation of the second device, only with hardware, it is possible to avoid errors caused by software, for example, and thus to more reliably start the protective operation.

[0014] (5) Preferably, the first device is a first indoor unit, and the second device is a second indoor unit or an outdoor unit.

[0015] (6) The first device is either a first indoor unit or a remote controller having an input unit for controlling the first indoor unit, and the second device is the other of the first indoor unit or the remote controller.

[0016] (7) Preferably, the second device further has a third circuit that short-circuits the first electric wire and the second electric wire when an abnormality in the second device is detected, and the first device further has a fourth circuit that initiates a protective operation of the first device when the first electric wire and the second electric wire are short-circuited.

[0017] By shorting the first and second electric wires used for communication between the first and second devices, an abnormality in the second device can be transmitted to the first device more quickly, thereby hastening the start of protective operation for the first device.

[0018] (8) Preferably, the first device includes a protection board including the first circuit and the fourth circuit, and a control board provided separately from the protection board and controlling an operation of the first device.

[0019] By providing the protection board separately from the control board, even if an abnormality occurs in the control board, the protection operation can be performed more reliably.

[0020] (9) Preferably, the first device includes a protection board including the first circuit, and a control board provided separately from the protection board and controlling an operation of the first device.

[0021] By providing the protection board separately from the control board, even if an abnormality occurs in the control board, the protection operation can be performed more reliably. [Brief description of the drawings]

[0022] [Figure 1] 1 is a diagram illustrating a schematic configuration of a refrigeration system according to an embodiment. [Diagram 2] FIG. 2 is a diagram showing a schematic internal configuration of a first indoor unit according to the embodiment. [Diagram 3] FIG. 4 is a diagram showing a schematic internal configuration of a second indoor unit according to the embodiment. [Figure 4] FIG. 2 is a diagram illustrating an outline of the internal configuration of the outdoor unit according to the embodiment. [Diagram 5] 1 is a flowchart illustrating an example of a protection method according to an embodiment. [Figure 6] 1 is a flowchart illustrating an example of a protection method according to an embodiment. [Figure 7] FIG. 10 is a diagram illustrating an outdoor unit according to a modified example. [Figure 8] FIG. 13 is a diagram illustrating a schematic configuration of a refrigeration system according to a modified example. [Figure 9] FIG. 10 is a diagram illustrating an internal configuration of a remote controller according to a modified example. [Figure 10] FIG. 10 is a diagram illustrating a first electric wire and a second electric wire according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0024] [Embodiment] [Overview of the refrigeration system] In the refrigeration system 10 according to the embodiment, when the first indoor unit 20 or the second indoor unit 30 enters an abnormal state, the first electric wire 60 and the second electric wire 70 used as communication lines are short-circuited, thereby more quickly transmitting the abnormal state to other devices (e.g., the outdoor unit 40) connected to the first electric wire 60 and the second electric wire 70.

[0025] [Overall configuration of refrigeration system] FIG. 1 is a diagram illustrating a schematic configuration of a refrigeration system 10 according to an embodiment of the present disclosure. FIG. 2 is a diagram showing a schematic internal configuration of the first indoor unit 20 according to the embodiment of the present disclosure. FIG. 3 is a diagram showing a schematic internal configuration of the second indoor unit 30 according to the embodiment of the present disclosure. FIG. 4 is a diagram showing a schematic internal configuration of the outdoor unit 40 according to the embodiment of the present disclosure.

[0026] Please refer to Figure 1. The refrigeration system 10 is a system that exchanges heat via a refrigerant. The refrigeration system 10 is, for example, an air conditioner for adjusting the temperature of an indoor space, a refrigeration device for freezing and storing food, or a refrigeration device for refrigerating and storing food. In this embodiment, the refrigeration system 10 will be representatively described as an air conditioner.

[0027] The refrigeration system 10 includes a first indoor unit 20, a second indoor unit 30, an outdoor unit 40, a refrigerant piping 50, a first electric wire 60, and a second electric wire 70. The first indoor unit 20 is an example of a "first device" in the present disclosure. The second indoor unit 30 is an example of a "second device" in the present disclosure. The outdoor unit 40 is an example of a "second device" in the present disclosure. The refrigeration system 10 may further include indoor units other than the first indoor unit 20 and the second indoor unit 30.

[0028] The first indoor unit 20 has a function of adjusting the temperature of the indoor space S11. The first indoor unit 20 is, for example, a ceiling-embedded indoor unit. A housing 25 (described later) included in the first indoor unit 20 is housed in the attic space S12 located above the indoor space S11. The first indoor unit 20 may be a ceiling-suspended type, a floor-standing type, or a wall-mounted type indoor unit. In this case, the housing 25 is installed in the indoor space S11.

[0029] The second indoor unit 30 has a function of adjusting the temperature of the indoor space S21. The indoor space S21 is a space located in a room separate from the indoor space S11. The second indoor unit 30 is, for example, a ceiling-embedded indoor unit. A housing 35 (described later) included in the second indoor unit 30 is housed in the attic space S22 located above the indoor space S21. The second indoor unit 30 may be a ceiling-suspended type, a floor-standing type, or a wall-mounted type indoor unit. In this case, the housing 35 is installed in the indoor space S21.

[0030] The outdoor unit 40 is installed in the outdoor space S31.

[0031] The refrigerant piping 50 is a pipe for circulating the refrigerant. The refrigerant piping 50 is connected to a heat exchanger 212 (to be described later) of the first indoor unit 20, a heat exchanger 312 (to be described later) of the second indoor unit 30, and a heat exchanger 412 (to be described later) of the outdoor unit 40, and circulates the refrigerant through the respective heat exchangers 212, 312, and 412.

[0032] The first electric wire 60 and the second electric wire 70 are electric wires that electrically connect the first indoor unit 20, the second indoor unit 30, and the outdoor unit 40, respectively. The first electric wire 60 and the second electric wire 70 function as communication lines that connect the first indoor unit 20, the second indoor unit 30, and the outdoor unit 40, respectively, so that they can communicate with each other.

[0033] Specifically, the first indoor unit 20 communicates with the second indoor unit 30 and the outdoor unit 40 by outputting a communication signal to the first electric wire 60 and the second electric wire 70. The second indoor unit 30 communicates with the first indoor unit 20 and the outdoor unit 40 by outputting a communication signal to the first electric wire 60 and the second electric wire 70. The outdoor unit 40 communicates with the first indoor unit 20 and the second indoor unit 30 by outputting a communication signal to the first electric wire 60 and the second electric wire 70.

[0034] 1 to 4, the first electric wire 60 has an outer region 61 and three inner regions 62, 64, and 66. The outer region 61 is a region that connects first terminals 241, 341, and 441 described below. The three inner regions 62, 64, and 66 are regions that connect the first terminals 241, 341, and 441 to control boards 22, 32, and 42 described below, respectively.

[0035] 1 to 4, the second electric wire 70 has an outer region 71 and three inner regions 72, 74, and 76. The outer region 71 is a region that connects second terminals 242, 342, and 442 described below. The three inner regions 72, 74, and 76 are regions that connect second terminals 242, 342, and 442 to control boards 22, 32, and 42 described below, respectively.

[0036] In this embodiment, two electric wires (the first electric wire 60 and the second electric wire 70) are used as the communication lines. However, three or more electric wires may be used as the communication lines. In this case, any two of the three or more electric wires are referred to as the first electric wire 60 and the second electric wire 70.

[0037] [Configuration of the first indoor unit] Please refer to Figures 1 and 2. The first indoor unit 20 has an operating unit 21, a control board 22, a protection board 23, a terminal block 24, a housing 25, a remote controller 26, and a sensor 27. A part of the operating unit 21, the control board 22, the protection board 23, and the terminal block 24 are housed in the housing 25.

[0038] The remote controller 26 and the sensor 27 are installed outside the housing 25. In this embodiment, the remote controller 26 and the sensor 27 are installed in the indoor space S11. The sensor 27 may be installed in the attic space S12 or inside the housing 25.

[0039] The remote controller 26 is connected to the control board 22 and the protection board 23 by wire or wirelessly. The remote controller 26 has a display unit 261 and an input unit 262. The display unit 261 includes, for example, an LED or a liquid crystal panel. The display unit 261 displays the status of the refrigeration system 10 (for example, the current set temperature, air volume, air direction, details of an error that has occurred in the refrigeration system 10, etc.) to the user in response to a command from the control unit 221 or the control circuit 237 described below. The input unit 262 includes buttons that allow the user to set the temperature, air volume, air direction, etc. When the input unit 262 receives an input from the user, it transmits the input to the control board 22 or the protection board 23.

[0040] The operating unit 21 has a fan 211, a heat exchanger 212, a display unit 213, a first ventilation device (not shown), and a first shutoff valve (not shown). The fan 211 and the heat exchanger 212 are housed in a housing 25. The display unit 213 is housed in the housing 25 in a state in which the display is visible to a user of the indoor space S11. The first ventilation device and the first shutoff valve are provided outside the housing 25.

[0041] The fan 211 takes in air from the indoor space S11 into the housing 25, and supplies the air (conditioned air) that has been heat exchanged in the heat exchanger 212 in the housing 25 to the indoor space S11. The heat exchanger 212 is, for example, a cross fin tube type heat exchanger. The heat exchanger 212 is connected to the refrigerant piping 50.

[0042] The display unit 213 includes, for example, an LED or a liquid crystal panel, and displays to the user the status of the refrigeration system 10. For example, the display unit 213 may light up a green LED to indicate normal operation, or may blink a yellow LED to indicate an error in the refrigeration system 10. The display unit 213 may also display the status of the first indoor unit 20 on a liquid crystal panel.

[0043] The first ventilation device (not shown) is a device for discharging air from the indoor space S11 to the outdoor space S31, and has a fan. The first ventilation device is provided, for example, on a wall that separates the indoor space S11 and the outdoor space S31.

[0044] The first shutoff valve (not shown) is a valve that controls the flow of the refrigerant piping 50, for example, upstream of the heat exchanger 212. The first shutoff valve is always open, and the refrigerant flows from the refrigerant piping 50 to the heat exchanger 212. When the first shutoff valve is closed, the heat exchanger 212 is separated from the refrigerant piping 50, and the flow of refrigerant from the refrigerant piping 50 to the first indoor unit 20 stops. The first shutoff valve is provided, for example, in the attic space S12.

[0045] The terminal block 24 is a component for connecting the first electric wire 60 and the second electric wire 70 to each portion inside the housing 25. The terminal block 24 has a first terminal 241 and a second terminal 242. The first terminal 241 is connected to the first electric wire 60. The second terminal 242 is connected to the second electric wire 70.

[0046] The control board 22 is a board that controls the normal operation of the first indoor unit 20, and has a control unit 221 and a communication unit 222. An arithmetic processing unit such as a microprocessor and a storage device such as a memory IC are mounted on the control board 22. The control unit 221 and the communication unit 222 are realized by the arithmetic processing unit reading out a program pre-stored in the storage device.

[0047] A first electric wire 60 and a second electric wire 70 are connected to the control board 22. Specifically, the first electric wire 60 (internal area 62) is connected between the first terminal 241 and the control board 22, and the second electric wire 70 (internal area 72) is connected between the second terminal 242 and the control board 22. Communication signals flowing through the first electric wire 60 and the second electric wire 70 are input to the communication unit 222.

[0048] The control unit 221 controls the operation of the operation unit 21 based on a pre-stored program and information input from the communication unit 222. The control unit 221 controls, for example, the rotation speed of the fan 211 and the display of the display unit 213. The control unit 221 also controls the display of the display unit 261 included in the remote controller 26.

[0049] The communication unit 222 communicates with other devices (for example, the second indoor unit 30 and the outdoor unit 40) included in the refrigeration system 10. The communication unit 222 converts a communication signal constituted by the potential difference between the first electric wire 60 and the second electric wire 70 into a digital signal, and transmits it to the control unit 221 as information input from the other devices. In addition, the communication unit 222 converts a digital signal output from the control unit 221 into a communication signal, and outputs it to the first electric wire 60 and the second electric wire 70.

[0050] The protection board 23 is a board provided separately from the control board 22, and controls the operation for protecting the first indoor unit 20. The protection board 23 has a first circuit 231 and a fourth circuit 232. The first circuit 231 and the fourth circuit 232 do not include a calculation processing device such as a microprocessor, and are composed only of hardware.

[0051] The first circuit 231 is a circuit that short-circuits the first electric wire 60 and the second electric wire 70 when an abnormality is detected in the first indoor unit 20. The first circuit 231 has an abnormality detection circuit 233 and a short circuit 235.

[0052] The abnormality detection circuit 233 is a circuit for detecting an abnormality related to leakage of the refrigerant. The abnormality detection circuit 233 is electrically connected to the sensor 27, the short circuit 235, and the control circuit 237. The abnormality detection circuit 233 detects an abnormality related to leakage of the refrigerant based on a detection signal of the sensor 27. The configuration of the sensor 27 will be described later.

[0053] Examples of abnormalities related to refrigerant leakage include refrigerant leakage from the refrigerant pipe 50, a malfunction of the sensor 27 for detecting refrigerant leakage, and the end of the life of the sensor 27. When the abnormality detection circuit 233 detects an abnormality related to refrigerant leakage, it outputs a predetermined electric signal to the short circuit 235 and the control circuit 237.

[0054] The short circuit 235 has an electric wire 63, an electric wire 73, and a switch 234. One end of the electric wire 63 is connected to the first terminal 241, and the other end of the electric wire 63 is connected to one side of the switch 234. One end of the electric wire 63 may be connected to the inner region 62 of the first electric wire 60. One end of the electric wire 73 is connected to the second terminal 242, and the other end of the electric wire 73 is connected to the other side of the switch 234. One end of the electric wire 73 may be connected to the inner region 72 of the second electric wire 70. With this configuration, the switch 234 is connected in parallel to the first electric wire 60 and the second electric wire 70 via the electric wire 63 and the electric wire 73.

[0055] The switch 234 is normally in an open state. When the abnormality detection circuit 233 detects an abnormality related to a refrigerant leak, a predetermined electric signal is input from the abnormality detection circuit 233 to the short circuit 235. Based on the predetermined electric signal, the switch 234 switches from an open state to a connected state. As a result, the first electric wire 60 and the second electric wire 70 are electrically connected via the electric wire 63, the switch 234, and the electric wire 73 with an electric resistance lower than that in a normal state (the first electric wire 60 and the second electric wire 70 are short-circuited by the short circuit 235).

[0056] The electric wire 63 and the electric wire 73 may include a resistive element having a low resistance. Even in this configuration, when the switch 234 is switched to the connected state, the first electric wire 60 and the second electric wire 70 are short-circuited. In the present disclosure, the term "short-circuited" includes a case where the first electric wire 60 and the second electric wire 70 are electrically connected with an electrical resistance close to zero, as well as a case where the first electric wire 60 and the second electric wire 70 are electrically connected via a resistive element having a low resistance. In either case, a large current flows between the first electric wire 60 and the second electric wire 70, which does not flow during normal communication.

[0057] The fourth circuit 232 is a circuit that starts a protection operation of the first indoor unit 20 when a short circuit occurs between the first electric wire 60 and the second electric wire 70. The fourth circuit 232 has a short circuit detection circuit 236 and a control circuit 237.

[0058] The short circuit detection circuit 236 is a circuit that detects a short circuit between the first electric wire 60 and the second electric wire 70. The short circuit detection circuit 236 has one end connected to the electric wire 63 and the other end connected to the electric wire 73. Note that the short circuit detection circuit 236 may have one end connected to the internal region 62 of the first electric wire 60 and the other end connected to the internal region 72 of the second electric wire 70. The short circuit detection circuit 236 is also electrically connected to the control circuit 237.

[0059] The short circuit detection circuit 236 detects, for example, a potential difference between the first electric wire 60 and the second electric wire 70. If the potential difference continues to be below a predetermined lower limit for a predetermined time (for example, beyond the 0 V output time in a normal communication signal), it outputs a predetermined electric signal to the control circuit 237, determining that the first electric wire 60 and the second electric wire 70 are shorted.

[0060] The short circuit detection circuit 236 may be a circuit (overcurrent detection circuit) that detects the current value of at least one of the first electric wire 60 and the second electric wire 70. In this case, the short circuit detection circuit 236 has a current sensor inserted into at least one of the first electric wire 60 and the second electric wire 70. When the current value detected by the current sensor exceeds a predetermined upper limit, the short circuit detection circuit 236 outputs a predetermined electric signal to the control circuit 237, determining that the first electric wire 60 and the second electric wire 70 are shorted.

[0061] The control circuit 237 is electrically connected to the operation unit 21. When the short circuit detection circuit 236 detects a short circuit between the first electric wire 60 and the second electric wire 70, a predetermined electric signal is input from the short circuit detection circuit 236 to the control circuit 237. When the predetermined electric signal is input, the control circuit 237 controls the operation unit 21 to cause the operation unit 21 to perform a protective operation against an abnormality.

[0062] The protection operations performed by the operation unit 21 include an abnormality suppression operation and an abnormality notification operation. The abnormality suppression operation includes an operation for recovering the refrigeration system 10 from an abnormal state to a normal state and for preventing the abnormal state of the refrigeration system 10 from further worsening. The abnormality notification operation includes an operation for notifying a user of an abnormality in the refrigeration system 10.

[0063] The abnormality suppression operation includes rotating fan 211 at the maximum rotation speed. The abnormality suppression operation also includes operating a first ventilation device (not shown) at the maximum air volume. These operations can quickly diffuse the leaked refrigerant and prevent a local increase in the refrigerant concentration. The rotation of fan 211 and the operation of the first ventilation device may be continued for, for example, a preset time, or until abnormality detection circuit 233 no longer detects an abnormality.

[0064] When the abnormality suppression operation includes the rotation of the fan 211 or the operation of the first ventilation device, the abnormality suppression operation may further include stopping the reception of an input from the input unit 262 of the remote controller 26. In this case, even if an input is made to the input unit 262, the input is not transmitted to the control unit 221. This operation makes it possible to avoid a situation in which other protective operations, such as rotating the fan 211, are stopped earlier than a preset time.

[0065] When stopping the acceptance of input from the input unit 262, in order to inform the user that the input will be invalid, a message such as "input not permitted" may be displayed on the display unit 261 of the remote controller 26 when the user presses a button included in the input unit 262.

[0066] The abnormality suppression operation includes closing a first shutoff valve (not shown) installed in the refrigerant piping 50. This operation stops the inflow of refrigerant from the refrigerant piping 50 to the first indoor unit 20, thereby suppressing further leakage of the refrigerant.

[0067] The abnormality notification operation includes displaying the leakage of refrigerant by light or sound on the display unit 213. In this case, an LED included in the display unit 213 may be caused to flash in a color (e.g., yellow or red) different from that during normal operation, a liquid crystal panel included in the display unit 213 may display in text that a refrigerant leak has occurred, or a speaker included in the display unit 213 may generate an alarm sound.

[0068] The abnormality notification operation includes displaying the fact that refrigerant has leaked by light or sound on the display unit 261 of the remote controller 26. By these operations, it is possible to notify the user that refrigerant has leaked.

[0069] The sensor 27 is a sensor that detects refrigerant leakage. The sensor 27 is electrically connected to the abnormality detection circuit 233. The sensor 27 is, for example, a sensor that detects the concentration of the refrigerant, and outputs the detected refrigerant concentration as a detection signal to the abnormality detection circuit 233. For example, the detection signal of the sensor 27 exceeding a predetermined upper limit value means that the refrigerant is leaking in excess of a specified concentration. Therefore, when a detection signal exceeding the predetermined upper limit value is input from the sensor 27 to the abnormality detection circuit 233, the abnormality detection circuit 233 detects an abnormality in the form of a refrigerant leakage.

[0070] Furthermore, if the detection signal of sensor 27 continues to be below a predetermined lower limit for a predetermined period of time (for example, the value of the detection signal of sensor 27 becomes zero), this means that sensor 27 has broken down and is not providing an accurate output. Therefore, if a detection signal below the predetermined lower limit is input from sensor 27 to abnormality detection circuit 233 (or if no detection signal is input), abnormality detection circuit 233 detects a failure of sensor 27.

[0071] The sensor 27 may be a sensor that directly detects the concentration of the refrigerant, or a sensor that indirectly detects the concentration of the refrigerant. Examples of the sensor 27 that indirectly detects the concentration of the refrigerant include a carbon dioxide sensor and an oxygen concentration sensor. When a refrigerant leak occurs, the concentration of the gas normally contained in the air decreases relatively as the concentration of the refrigerant in the air increases. Therefore, the sensor 27 detects the decrease in the concentration of the gas normally contained in the air, thereby indirectly detecting the increase in the concentration of the refrigerant.

[0072] When sensor 27 is a sensor that detects the concentration of oxygen, it outputs the detected oxygen concentration as a detection signal to abnormality detection circuit 233. For example, the detection signal of sensor 27 falling below a predetermined lower limit means that the oxygen concentration is below a specified concentration, and it is predicted that the refrigerant is leaking at a concentration exceeding the specified concentration. Therefore, when a detection signal falling below the specified lower limit is input from sensor 27 (oxygen concentration sensor) to abnormality detection circuit 233, abnormality detection circuit 233 detects an abnormality of refrigerant leakage.

[0073] Furthermore, the sensor 27 may be a pressure sensor provided in the refrigerant pipe 50. The sensor 27 detects the pressure of the refrigerant in the refrigerant pipe 50, and outputs the detected pressure as a detection signal to the abnormality detection circuit 233. When a refrigerant leak occurs, the pressure of the refrigerant in the refrigerant pipe 50 decreases. Therefore, for example, when the detection signal of the sensor 27 falls below a predetermined lower limit, the abnormality detection circuit 233 detects an abnormality of a refrigerant leak as a result of refrigerant leaking from the refrigerant pipe 50 in excess of a predetermined amount.

[0074] The abnormality detection circuit 233 may include, for example, a built-in counter. The counter counts the time that the sensor 27 and the abnormality detection circuit 233 are energized, and records the accumulated value of the energization time. When the accumulated value exceeds a predetermined upper limit, the abnormality detection circuit 233 detects an abnormality, assuming that the sensor 27 has reached the end of its life due to aging. For safety reasons, the predetermined upper limit may be set to be shorter than the actual life of the sensor 27 due to aging. When the sensor 27 is replaced with a new sensor 27, the accumulated value of the energization time in the counter of the abnormality detection circuit 233 is reset.

[0075] [Configuration of the second indoor unit] Please refer to Figures 1 and 3. The second indoor unit 30 has an operating unit 31, a control board 32, a protection board 33, a terminal block 34, a housing 35, a remote controller 36, and a sensor 37. These components are similar to the operating unit 21, control board 22, protection board 23, terminal block 24, housing 25, remote controller 26, and sensor 27 of the first indoor unit 20, respectively. Descriptions of components of the second indoor unit 30 that are common to the first indoor unit 20 will be omitted as appropriate.

[0076] In this embodiment, the remote controller 36 and the sensor 37 are installed in the indoor space S21. The sensor 37 may be installed in the ceiling space S22 or inside the housing 35.

[0077] The remote controller 36 includes a display unit 361 and an input unit 362. The display unit 361 and the input unit 362 have the same configurations as the display unit 261 and the input unit 262, respectively.

[0078] The operation unit 31 has a fan 311, a heat exchanger 312, a display unit 313, a second ventilation device (not shown), and a second shutoff valve (not shown), which are similar in configuration to the fan 211, the heat exchanger 212, the display unit 213, the first ventilation device (not shown), and the first shutoff valve (not shown), respectively.

[0079] The fan 311 takes in air from the indoor space S21 into the housing 35 and supplies the air (conditioned air) that has been subjected to heat exchange by the heat exchanger 312 in the housing 35 to the indoor space S21. The second ventilation device (not shown) is a device for discharging the air from the indoor space S21 to the outdoor space S31 and has a fan. The second ventilation device is provided, for example, in a wall that separates the indoor space S21 and the outdoor space S31. The second shutoff valve is provided, for example, in the attic space S22.

[0080] The terminal block 34 has a first terminal 341 and a second terminal 342. These terminals have the same configurations as the first terminal 241 and the second terminal 242, respectively.

[0081] The control board 32 is a board that controls the normal operation of the second indoor unit 30, and has a control unit 321 and a communication unit 322. These configurations are similar to those of the control unit 221 and the communication unit 222, respectively. A first electric wire 60 and a second electric wire 70 are connected to the control board 32. Specifically, the first electric wire 60 (internal area 64) is connected between the first terminal 341 and the control board 32, and the second electric wire 70 (internal area 74) is connected between the second terminal 342 and the control board 32. The communication unit 322 communicates with other devices (e.g., the first indoor unit 20, the outdoor unit 40) included in the refrigeration system 10.

[0082] The protection substrate 33 has a third circuit 331 and a second circuit 332. The third circuit 331 and the second circuit 332 are configured only by hardware. The third circuit 331 has a similar configuration to the first circuit 231, and the second circuit 332 has a similar configuration to the fourth circuit 232.

[0083] The third circuit 331 has an abnormality detection circuit 333 and a short circuit 335. The short circuit 335 has an electric wire 65, an electric wire 75, and a switch 334. These components are similar to the abnormality detection circuit 233, the short circuit 235, the electric wire 63, the electric wire 73, and the switch 234, respectively.

[0084] The second circuit 332 is a circuit that starts a protection operation for the second indoor unit 30 when a short circuit occurs between the first electric wire 60 and the second electric wire 70. The second circuit 332 has a short circuit detection circuit 336 and a control circuit 337. These circuits have the same configurations as the short circuit detection circuit 236 and the control circuit 237, respectively.

[0085] [Outdoor unit configuration] Please refer to Figures 1 and 4. The outdoor unit 40 has an operating unit 41, a control board 42, a protection board 43, a terminal block 44, and a housing 45. These components are similar to the operating unit 21, the control board 22, the protection board 23, the terminal block 24, and the housing 25 of the first indoor unit 20, respectively. Of the outdoor unit 40, the components common to the first indoor unit 20 will not be described as appropriate.

[0086] The operating unit 41 has a fan 411, a heat exchanger 412, and a third shutoff valve (not shown). These have the same configurations as the fan 211, the heat exchanger 212, and the first shutoff valve (not shown), respectively. The operating unit 41 further has a compressor 413 for compressing the refrigerant. The compressor 413 is connected to the refrigerant pipe 50.

[0087] The fan 411 takes in air from the outdoor space S31 into the housing 45, and discharges the air that has been subjected to heat exchange by the heat exchanger 412 in the housing 45 to the outdoor space S31. The third shutoff valve is provided in the housing 45, for example.

[0088] The terminal block 44 has a first terminal 441 and a second terminal 442. These terminals have the same configurations as the first terminal 241 and the second terminal 242, respectively.

[0089] The control board 42 is a board that controls normal operation of the outdoor unit 40, and has a control unit 421 and a communication unit 422. These configurations are similar to those of the control unit 221 and the communication unit 222, respectively. A first electric wire 60 and a second electric wire 70 are connected to the control board 42. Specifically, the first electric wire 60 (internal area 66) is connected between the first terminal 441 and the control board 42, and the second electric wire 70 (internal area 76) is connected between the second terminal 442 and the control board 42. The communication unit 422 communicates with other devices included in the refrigeration system 10 (for example, the first indoor unit 20 and the second indoor unit 30).

[0090] The protection substrate 43 has a second circuit 432. The second circuit 432 is configured only by hardware. The second circuit 432 has a similar configuration to the fourth circuit 232.

[0091] The second circuit 432 is a circuit that starts a protection operation of the outdoor unit 40 when a short circuit occurs between the first electric wire 60 and the second electric wire 70. The second circuit 432 has a short circuit detection circuit 436 and a control circuit 437.

[0092] The short circuit detection circuit 436 is a circuit that detects a short circuit between the first electric wire 60 and the second electric wire 70. The short circuit detection circuit 436 has one end connected to the internal area 66 and the other end connected to the internal area 76. The short circuit detection circuit 436 is also electrically connected to a control circuit 437.

[0093] The short circuit detection circuit 436 detects, for example, a potential difference between the first electric wire 60 and the second electric wire 70. If the potential difference continues to be below a predetermined lower limit for a predetermined time, the short circuit detection circuit 436 outputs a predetermined electric signal to the control circuit 437, indicating that the first electric wire 60 and the second electric wire 70 are shorted.

[0094] The short circuit detection circuit 436 may be a circuit (overcurrent detection circuit) that detects the current value of at least one of the first electric wire 60 and the second electric wire 70. In this case, when the current value exceeds a predetermined upper limit, it is determined that the first electric wire 60 and the second electric wire 70 are shorted, and a predetermined electric signal is output to the control circuit 437.

[0095] The control circuit 437 is electrically connected to the operation unit 41. When the short circuit detection circuit 436 detects a short circuit between the first electric wire 60 and the second electric wire 70, a predetermined electric signal is input from the short circuit detection circuit 436 to the control circuit 437. When the predetermined electric signal is input, the control circuit 437 controls the operation unit 41 to cause the operation unit 41 to perform a protective operation against an abnormality.

[0096] The protection operation performed by the operation unit 41 includes an abnormality suppression operation. The abnormality suppression operation includes an operation for recovering the refrigeration system 10 from an abnormal state to a normal state and for preventing the abnormal state of the refrigeration system 10 from worsening further.

[0097] The abnormality suppression operation includes stopping the compressor 413. The abnormality suppression operation also includes closing the third shutoff valve (not shown). These operations stop the circulation of the refrigerant in the refrigerant pipe 50, so that further leakage of the refrigerant can be suppressed.

[0098] The abnormality suppression operation also includes stopping the compressor 413 and closing the third shutoff valve, followed by interlocking the outdoor unit 40. In this case, the compressor 413 will not start and the third shutoff valve will not open in the outdoor unit 40 unless a predetermined input condition is satisfied. This operation makes it possible to prevent the compressor 413 and the like from unintentionally restarting operation while an abnormal state such as a refrigerant leak continues.

[0099] [Protection methods in refrigeration systems] 1 through 5, where appropriate, a method of protection for a refrigeration system 10 will be described. FIG. 5 is a flow chart illustrating an example of a method for protecting the refrigeration system 10.

[0100] First, the operation of the first indoor unit 20 will be described. For example, consider a case where refrigerant leaks from a portion of the refrigerant piping 50 connected to the first indoor unit 20 (for example, a piping joint) into the ceiling space S12 and the indoor space S11. In this case, first the sensor 27 detects the refrigerant and outputs a detection signal to the abnormality detection circuit 233. Then, when the detection signal exceeds a predetermined upper limit, the abnormality detection circuit 233 determines that the refrigerant is leaking at a concentration greater than a specified level, detects an abnormality related to the refrigerant leakage, and outputs a predetermined electrical signal to the short circuit 235 and the control circuit 237 (abnormality detection process ST21).

[0101] When a predetermined electric signal is input from the abnormality detection circuit 233 to the short circuit 235, the switch 234 switches from an open state to a connected state, whereby the first electric wire 60 and the second electric wire 70 are short-circuited (short-circuiting step ST22).

[0102] Next, the short circuit detection circuit 236 detects a short circuit between the first electric wire 60 and the second electric wire 70, and outputs a predetermined electric signal to the control circuit 237 (short circuit detection step ST23).

[0103] When the predetermined electric signal is input to the control circuit 237, the control circuit 237 causes the operation unit 21 to perform a protective operation against the abnormality (protective operation step ST24).

[0104] The control circuit 237 may cause the operation unit 21 to perform a protective operation against an abnormality when a predetermined electrical signal is input from the abnormality detection circuit 233 or when a predetermined electrical signal is input from the short circuit detection circuit 236, whichever occurs first. By configuring in this manner, in the first indoor unit 20 in which an abnormality has occurred, the protective operation step ST24 can be performed immediately after the abnormality detection step ST21. This makes it possible to omit the short circuit step ST22 and the short circuit detection step ST23, and therefore makes it possible to start the protective operation against an abnormality more quickly.

[0105] Next, the operation of the second indoor unit 30 will be described. The second indoor unit 30 is connected to the first electric wire 60 and the second electric wire 70. Therefore, when the first electric wire 60 and the second electric wire 70 are short-circuited at the first time t1 due to the above-mentioned short-circuiting step ST22, the short-circuit detection circuit 336 of the second indoor unit 30 detects the short-circuit between the first electric wire 60 and the second electric wire 70 at the second time t2 that is later than the first time t1, and outputs a predetermined electric signal to the control circuit 337 (short-circuit detection step ST31).

[0106] When the predetermined electric signal is input to the control circuit 337, the control circuit 337 causes the operation unit 31 to perform a protective operation against the abnormality (protective operation step ST32).

[0107] Next, the operation of the outdoor unit 40 will be described. The outdoor unit 40 is connected to the first electric wire 60 and the second electric wire 70. Therefore, when the first electric wire 60 and the second electric wire 70 are short-circuited at the first time t1 due to the above-mentioned short-circuiting step ST22, the short-circuit detection circuit 436 of the outdoor unit 40 detects the short-circuit between the first electric wire 60 and the second electric wire 70 at the second time t2 that is later than the first time t1, and outputs a predetermined electric signal to the control circuit 437 (short-circuit detection step ST41).

[0108] When the predetermined electric signal is input to the control circuit 437, the control circuit 437 causes the operation unit 41 to perform a protective operation against the abnormality (protective operation step ST42).

[0109] [Comparison with conventional protection methods] Here, a conventional protection method will be described. Conventionally, when an abnormality related to refrigerant leakage occurs and the abnormality is detected in the first indoor unit 20, the first indoor unit 20 transmits a communication signal to the first electric wire 60 and the second electric wire 70 as communication lines to notify the abnormality to the second indoor unit 30 and the outdoor unit 40.

[0110] More specifically, when an abnormality such as a refrigerant leak is detected in the first indoor unit 20, an electrical signal for transmitting the abnormality is input from the abnormality detection circuit 233 to the control unit 221. The control unit 221 then generates a predetermined digital signal (e.g., an error code) for transmitting the abnormality to other devices (e.g., the second indoor unit 30 and the outdoor unit 40) and outputs the digital signal to the communication unit 222. The communication unit 222 converts the digital signal into a communication signal and outputs it to the first electric wire 60 and the second electric wire 70.

[0111] In the second indoor unit 30, the communication unit 322 converts the communication signals input from the first electric wire 60 and the second electric wire 70 into digital signals, and outputs the converted digital signals to the control unit 321. The control unit 321 analyzes the input digital signals to determine the type of error (in this example, refrigerant leakage) and causes the operation unit 31 to perform protective operation.

[0112] As described above, in the conventional protection method, an abnormality is transmitted from the abnormality detection circuit 233 of the first indoor unit 20 to the control unit 321 of the second indoor unit 30 via the control unit 221, communication unit 222, the first electric wire 60 and the second electric wire 70, and the communication unit 322 in this order. For this reason, in both the device that detects the abnormality (for example, the first indoor unit 20) and the device to which the abnormality is transmitted (for example, the second indoor unit 30), processing (signal generation processing or analysis processing) in the control units 221, 321 and signal conversion processing in the communication units 222, 322 were required. Since these processes include arithmetic processing in a calculation processing device such as a microprocessor, it took, for example, about one minute for the abnormality to be transmitted from one device to the other device.

[0113] In contrast, in the refrigeration system 10 of this embodiment, the first indoor unit 20 has a short circuit 235, and when the abnormality detection circuit 233 detects an abnormality, the short circuit 235 shorts the first electric wire 60 and the second electric wire 70 serving as communication lines. Then, when the short circuit detection circuits 336, 436 of the second indoor unit 30 and the outdoor unit 40 detect a short circuit, the control circuits 337, 437 cause the operating units 31, 41 to perform a protective operation.

[0114] This series of operations does not include any calculation processing such as generating an error code or converting a communication signal, and the abnormality is communicated based on the simple criteria of the presence or absence of a specific electrical signal. Therefore, the time from when the abnormality detection circuit 233 of the first indoor unit 20 detects an abnormality to when the operating units 31, 41 start protective operation is within 30 seconds, for example, making it possible to communicate the abnormality more quickly than before.

[0115] In the refrigeration system 10, the protection board 23 is provided as a separate body from the control board 22. With this configuration, even if an abnormality occurs in the control board 22, the protection operation can be performed more reliably. Furthermore, the control unit 221 of the control board 22 may be provided so as to be able to communicate with each unit (e.g., the control circuit 237) of the protection board 23. In this case, since the control board 22 and the protection board 23 are provided as separate bodies, when an abnormality occurs in the protection board 23, the control board 22 can detect the abnormality of the protection board 23 based on the fact that it cannot communicate with the protection board 23. When the control board 22 detects the abnormality of the protection board 23, the control unit 221 causes the operation unit 21 to perform the protection operation and transmits the abnormality to another device (e.g., the second indoor unit 30) via the communication unit 222.

[0116] In this way, by separating the control board 22 and the protection board 23, even if an abnormality occurs in either the control board 22 or the protection board 23, the operation unit 21 can execute a protection operation and the abnormality can be transmitted to other devices. As a result, the reliability of the protection operation and the abnormality transmission of the refrigeration system 10 can be improved.

[0117] [Variations] The present disclosure is not limited to the above-described embodiment, and various modifications are possible. In the following modifications, the same components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0118] [Modification of protection method in refrigeration system] FIG. 6 is a flow chart illustrating an alternative method for protecting the refrigeration system 10. 5 considers a case where the first indoor unit 20 detects an abnormality. In Fig. 6 considers a case where the second indoor unit 30 detects an abnormality.

[0119] First, the operation of the second indoor unit 30 will be described. For example, consider a case where refrigerant leaks from a portion of the refrigerant piping 50 connected to the second indoor unit 30 (for example, a piping joint) into the ceiling space S22 and the room space S21. In this case, first the sensor 37 detects the refrigerant and outputs a detection signal to the abnormality detection circuit 333. Then, when the detection signal exceeds a predetermined upper limit, the abnormality detection circuit 333 determines that the refrigerant is leaking at a concentration greater than a specified level, detects an abnormality in the second indoor unit 30, and outputs a predetermined electrical signal to the short circuit 335 and the control circuit 337 (abnormality detection process ST33).

[0120] When a predetermined electric signal is input from the abnormality detection circuit 333 to the short circuit 335, the switch 334 switches from an open state to a connected state, whereby the first electric wire 60 and the second electric wire 70 are short-circuited (short-circuiting step ST34).

[0121] Next, the short circuit detection circuit 336 detects a short circuit between the first electric wire 60 and the second electric wire 70, and outputs a predetermined electric signal to the control circuit 337 (short circuit detection step ST35).

[0122] When the predetermined electric signal is input to the control circuit 337, the control circuit 337 causes the operation unit 31 to perform a protective operation against the abnormality (protective operation step ST36).

[0123] The control circuit 337 may cause the operation unit 31 to perform a protective operation against an abnormality when a predetermined electrical signal is input from the abnormality detection circuit 333 or when a predetermined electrical signal is input from the short circuit detection circuit 336, whichever occurs first. By configuring in this manner, in the second indoor unit 30 in which an abnormality has occurred, the protective operation step ST36 can be performed immediately after the abnormality detection step ST33. This makes it possible to omit the short circuit step ST34 and the short circuit detection step ST35, and therefore allows the protective operation against an abnormality to be started more quickly.

[0124] Next, the operation of the first indoor unit 20 will be described. The first indoor unit 20 is connected to the first electric wire 60 and the second electric wire 70. Therefore, when the first electric wire 60 and the second electric wire 70 are short-circuited at the first time t3 due to the above-mentioned short-circuiting step ST34, the short-circuit detection circuit 236 of the first indoor unit 20 detects the short-circuit between the first electric wire 60 and the second electric wire 70 at the second time t4 after the first time t3, and outputs a predetermined electric signal to the control circuit 237 (short-circuit detection step ST31).

[0125] When the predetermined electric signal is input to the control circuit 237, the control circuit 237 causes the operation unit 21 to perform a protective operation against the abnormality (protective operation step ST25).

[0126] Next, the operation of the outdoor unit 40 will be described. The outdoor unit 40 is connected to the first electric wire 60 and the second electric wire 70. Therefore, when the first electric wire 60 and the second electric wire 70 are short-circuited at the first time t3 due to the above-mentioned short-circuiting step ST34, the short-circuit detection circuit 436 of the outdoor unit 40 detects the short-circuit between the first electric wire 60 and the second electric wire 70 at the second time t4 that is later than the first time t3, and outputs a predetermined electric signal to the control circuit 437 (short-circuit detection step ST43).

[0127] When the predetermined electric signal is input to the control circuit 437, the control circuit 437 causes the operation unit 41 to perform a protective operation against the abnormality (protective operation step ST44).

[0128] As described above, even if an abnormality occurs in the second indoor unit 30, the abnormality can be transmitted more quickly to the first indoor unit 20 and the outdoor unit 40 by short-circuiting the first electric wire 60 and the second electric wire 70, which serve as communication lines.

[0129] [Variations of outdoor unit] In the above embodiment, the protection board 43 of the outdoor unit 40 has a second circuit 432 for causing the operation unit 41 to perform a protection operation when a short circuit is detected. The protection board 43 may further have a third circuit 431 for short-circuiting the first electric wire 60 and the second electric wire 70 when an abnormality is detected.

[0130] 7 is a diagram showing an outdoor unit 40a according to a modified example. The outdoor unit 40a differs from the outdoor unit 40 according to the above embodiment in that it further includes a third circuit 431 and a sensor 47. The sensor 47 has a similar configuration to the sensors 27 and 37, and detects, for example, the concentration of refrigerant leaked from the outdoor unit 40a. The third circuit 431 includes an abnormality detection circuit 433 and a short circuit 435.

[0131] The abnormality detection circuit 433 has a configuration similar to that of the abnormality detection circuits 233 and 333, and is electrically connected to the sensor 47. When the abnormality detection circuit 433 detects an abnormality in the outdoor unit 40a based on a detection signal from the sensor 47, the abnormality detection circuit 433 outputs a predetermined electrical signal to the short circuit 435 and the control circuit 437.

[0132] The short circuit 435 has the same configuration as the short circuits 235 and 335, and includes electric wires 67 and 77 and a switch 434. The electric wires 67 and 77 are connected to a first terminal 441 and a second terminal 442, respectively. When a predetermined electric signal is input from the abnormality detection circuit 433 to the short circuit 435, the switch 434 switches from an open state to a connected state. As a result, the first electric wire 60 and the second electric wire 70 are short-circuited.

[0133] By configuring in this way, an abnormality in the outdoor unit 40a can be more quickly transmitted to the first indoor unit 20 and the second indoor unit 30. In this case, the outdoor unit 40a may function as the "first device" of the present disclosure.

[0134] [Modifications of refrigeration system] 8 is a diagram showing a schematic configuration of a refrigeration system 10a according to a modified example. When the first indoor unit 20 is in an abnormal state, the refrigeration system 10a shorts the first electric wire 60 and the second electric wire 70 used as communication lines to more quickly transmit the abnormal state to another device (e.g., a remote controller 80) connected to the first electric wire 60 and the second electric wire 70.

[0135] The refrigeration system 10a includes a first indoor unit 20, a second indoor unit 30, an outdoor unit 40 (not shown in FIG. 8), a refrigerant pipe 50 (not shown in FIG. 8), a first electric wire 60, a second electric wire 70, and a plurality of remote controllers 80a, 80b, and 80c. When there is no particular need to distinguish between the remote controllers 80a, 80b, and 80c, they will be simply referred to as "remote controller 80." In this modification, the first indoor unit 20 is an example of a "first device," and the remote controller 80 is an example of a "second device."

[0136] The remote controllers 80a, 80b are wired remote controllers connected in a one-to-one relationship to the indoor units 20, 30. Specifically, the remote controller 80a is communicatively connected to the first indoor unit 20 via the external area 68 of the first electric wire 60 and the external area 78 of the second electric wire 70. The remote controller 80b is communicatively connected to the second indoor unit 30 via the external area 68 of the first electric wire 60 and the external area 78 of the second electric wire 70. For example, the remote controller 80a is installed in the indoor space S11 (FIG. 1), and the remote controller 80b is installed in the indoor space S21 (FIG. 1).

[0137] The remote controller 80c is a wired remote controller connected in a one-to-many relationship to the multiple indoor units 20, 30, and is also referred to as a centralized management device. Specifically, the remote controller 80c is communicatively connected to the first indoor unit 20 and the second indoor unit 30 via the external area 69 of the first electric wire 60 and the external area 79 of the second electric wire 70. For example, the remote controller 80c is installed in a space (such as a machine room) different from the indoor space S11 and the indoor space S21.

[0138] 9 is a diagram showing a schematic internal configuration of the remote controller 80a. The remote controller 80a has a control board 82, a protection board 83, a terminal block 84, a housing 85, and a sensor 87. These configurations are similar to the control board 22, protection board 23, terminal block 24, housing 25, and sensor 27 of the first indoor unit 20, respectively. Of the remote controller 80a, explanations of configurations common to the first indoor unit 20 will be omitted as appropriate.

[0139] The remote controller 80a further has an operation unit 81. The operation unit 81 has a display unit 811 that displays various information to the user, and an input unit 812 that receives input from the user. The display unit 811 includes a display and a speaker, and performs various displays based on commands from a control unit 821 and a control circuit 837, which will be described later. The input unit 812 receives input for controlling the first indoor unit 20. For example, the input unit 812 includes buttons that allow the user to set the temperature, air volume, air direction, and the like. When the input unit 812 receives input from the user, it transmits the input to the control unit 821, which will be described later.

[0140] The control board 82 is a board that controls normal operations of the remote controller 80a, and has a control unit 821 and a communication unit 822. These configurations are similar to those of the control unit 221 and the communication unit 222, respectively. The first electric wire 60 and the second electric wire 70 are connected to the control board 82. Specifically, the first electric wire 60 (internal area 601) is connected between the first terminal 841 and the control board 82, and the second electric wire 70 (internal area 701) is connected between the second terminal 842 and the control board 82. The communication unit 822 communicates with other devices (for example, the first indoor unit 20) included in the refrigeration system 10a.

[0141] The protection substrate 83 has a third circuit 831 and a second circuit 832. The third circuit 831 and the second circuit 832 are configured only by hardware. The third circuit 831 has a similar configuration to the first circuit 231, and the second circuit 832 has a similar configuration to the fourth circuit 232.

[0142] The third circuit 831 has an abnormality detection circuit 833 and a short circuit 835. The short circuit 835 has an electric wire 602, an electric wire 702, and a switch 834. These configurations are similar to those of the abnormality detection circuit 233, the short circuit 235, the electric wire 63, the electric wire 73, and the switch 234, respectively.

[0143] The second circuit 832 is a circuit that starts a protection operation of the remote controller 80a when a short circuit occurs between the first electric wire 60 and the second electric wire 70. The second circuit 832 has a short circuit detection circuit 836 and a control circuit 837. These circuits have the same configurations as the short circuit detection circuit 236 and the control circuit 237, respectively.

[0144] When the short circuit detection circuit 836 detects a short circuit between the first electric wire 60 and the second electric wire 70 and a predetermined electric signal is input to the control circuit 837, the control circuit 837 controls the operation unit 81 to cause the operation unit 81 to perform a protective operation against the abnormality. The protective operation performed by the operation unit 81 includes an abnormality notification operation. The abnormality notification operation of this modification includes causing the display unit 811 to display, by light or sound, that the refrigerant has leaked. These operations can notify the user that the refrigerant has leaked.

[0145] The terminal block 84 has a first terminal 841 and a second terminal 842. These terminals have the same configurations as the first terminal 241 and the second terminal 242. The outer region 68 of the first electric wire 60 electrically connects the first terminal 841 to the first terminal 241 (FIG. 2), and the outer region 78 of the second electric wire 70 electrically connects the second terminal 842 to the second terminal 242 (FIG. 2).

[0146] The remote controller 80b differs from the remote controller 80a in that it has an input section 812 for controlling the second indoor unit 30, but other configurations are common to the remote controller 80a, so description thereof will be omitted.

[0147] The remote controller 80c has an input unit 812 for controlling the first indoor unit 20 and the second indoor unit 30. Moreover, the remote controller 80c does not have the third circuit 831 and the sensor 87, and a short circuit detection circuit 836 is electrically connected to the internal area 601 and the internal area 701. In these respects, the remote controller 80c differs from the remote controller 80a, and other configurations are common to the remote controller 80a, so description thereof will be omitted.

[0148] Next, the operation of the refrigeration system 10a will be described. When the abnormality detection circuit 233 detects an abnormality based on a detection signal from the sensor 27 of the first indoor unit 20 (FIG. 2), the short circuit 235 shorts the first electric wire 60 and the second electric wire 70. As a result, the external area 68 and the external area 78 are shorted. The external area 69 and the external area 79 are also shorted. As a result, in the remote controller 80, the short circuit detection circuit 836 detects the short circuit, and the control circuit 837 causes the operation unit 81 to perform a protection operation. For example, the display unit 811 sounds a buzzer to inform the user of an abnormality related to refrigerant leakage.

[0149] As described above, when the first indoor unit 20 (an example of a first device) detects an abnormality related to refrigerant leakage, the remote controller 80 (an example of a second device) detects the abnormality by detecting a short circuit between the first electric wire 60 and the second electric wire 70, and can perform protective action more quickly.

[0150] In this modification, the remote controller 80 may detect an abnormality related to refrigerant leakage. Specifically, when the abnormality detection circuit 833 detects the above based on a detection signal from the sensor 87 of the remote controller 80a, the short circuit 835 shorts the first electric wire 60 and the second electric wire 70. As a result, in the first indoor unit 20, the short circuit detection circuit 236 detects the short circuit, and the control circuit 237 causes the operation unit 81 to perform a protection operation.

[0151] In this case, the remote controller 80 functions as the "first device" of the present disclosure, the third circuit 831 functions as the "first circuit", and the second circuit 832 functions as the "fourth circuit". Furthermore, the first indoor unit 20 functions as the "second device" of the present disclosure, and the first circuit 231 functions as the "third circuit". In this way, the remote controller 80 and the first indoor unit 20 have both the function of the "first device" and the function of the "second device" of the present disclosure.

[0152] In the above modification, the remote controller 80c (centralized control device) is communicatively connected to the first indoor unit 20 and the second indoor unit 30 via the first electric wire 60 and the second electric wire 70. However, the connection mode of the remote controller 80c is not limited to this. For example, the remote controller 80c may be communicatively connected to a plurality of outdoor units 40 (for example, the first outdoor unit 401, the second outdoor unit 402) via the first electric wire 60 and the second electric wire 70. In this case, for example, when an abnormality related to refrigerant leakage is detected in the first outdoor unit 401 and the first electric wire 60 and the second electric wire 70 are short-circuited, the remote controller 80c detects the short-circuit of the first electric wire 60 and the second electric wire 70 and causes the operation unit 81 to perform a protection operation.

[0153] [Modification of refrigerant piping] In the above embodiment, the refrigerant piping 50 circulates the refrigerant to both the first device (e.g., the first indoor unit 20) and the second device (e.g., the second indoor unit 30). However, it is not essential that the refrigerant piping 50 circulates the refrigerant to both the first device and the second device, and the refrigerant may circulate the refrigerant only to the first device or only to the second device.

[0154] For example, in a refrigeration system 10a (FIG. 8) according to a modified example, the refrigerant piping 50 is not connected to the remote controller 80. For this reason, for example, when the remote controller 80 functions as a second device, the refrigerant piping 50 only needs to circulate the refrigerant to the first device (for example, the first indoor unit 20), and it is not essential to circulate the refrigerant to both the first device and the second device.

[0155] [Modifications of the first electric wire and the second electric wire] FIG. 10 is a diagram that illustrates a first electric wire 60 and a second electric wire 70 according to a modified example. In the above embodiment, for example, the first indoor unit 20 (an example of a first device), the second indoor unit 30 (an example of a second device), and the outdoor unit 40 (an example of a second device) are directly connected by the first electric wire 60 and the second electric wire 70 without any other device being inserted therebetween. However, it is only necessary that the first electric wire 60 and the second electric wire 70 electrically connect the first indoor unit 20, the second indoor unit 30, and the outdoor unit 40, and the first indoor unit 20, the second indoor unit 30, and the outdoor unit 40 do not have to be directly connected to each other.

[0156] For example, as shown in FIG. 10(a), by inserting a device D1 (e.g., an amplifier circuit) between the first indoor unit 20 and the second indoor unit 30, the first electric wire 60 may be divided into two wires, a first region 61a and a second region 61b, and the second electric wire 70 may be divided into two wires, a first region 71a and a second region 71b.

[0157] 10(b), the first electric wire 60 and the second electric wire 70 may be branched by inserting a device D2 (for example, a branch circuit) between the first indoor unit 20, the second indoor unit 30, and the outdoor unit 40. In this case, the first electric wire 60 may be divided into three lines: a first region 61c connected from the device D2 to the first indoor unit 20, a second region 61d connected from the device D2 to the second indoor unit 30, and a third region 61e connected from the device D2 to the outdoor unit 40. The second electric wire 70 may be divided into three lines: a first region 71c connected from the device D2 to the first indoor unit 20, a second region 71d connected from the device D2 to the second indoor unit 30, and a third region 71e connected from the device D2 to the outdoor unit 40.

[0158] In addition, the first electric wire 60 and the second electric wire 70 only need to have two poles, and are not necessarily physically separated into two wires. For example, the first electric wire 60 and the second electric wire 70 may be bundled together in one cable.

[0159] [Modification of the protection substrate] The protective substrate 23 in the above embodiment has the first circuit 231 and the fourth circuit 232. However, the protective substrate 23 does not have to have the fourth circuit 232. In this case, the abnormality detection circuit 233 of the first circuit 231 may be electrically connected to the control unit 221 and may output a predetermined electrical signal to the control unit 221 when an abnormality is detected.

[0160] [Modification of the location of the protective board] The protective substrate 23 in the above embodiment is housed in the housing 25. However, the protective substrate 23 may be installed outside the housing 25. In this case, the protective substrate 23 may be housed in a second housing (not shown) provided in the attic space S12 separately from the housing 25. In addition to the protective substrate 23, the second housing may house, for example, a sensor 27. Similarly, the protective substrates 33 and 43 may be installed outside the housings 35 and 45.

[0161] [Modification of protection operation] The control circuit 237 may determine the content of the protection operation depending on whether or not a predetermined electrical signal is input from the abnormality detection circuit 233. For example, when predetermined electrical signals are input to the control circuit 237 from both the short circuit detection circuit 236 and the abnormality detection circuit 233, an abnormality has occurred in the first indoor unit 20 itself. For this reason, the control circuit 237 performs both an abnormality suppression operation (for example, rotation of the fan 211 at the maximum rotation speed) and an abnormality notification operation (for example, blinking an LED on the display unit 213) as a protection operation.

[0162] On the other hand, for example, if a predetermined electrical signal is input from the short circuit detection circuit 236 to the control circuit 237 but no predetermined electrical signal is input from the abnormality detection circuit 233 to the control circuit 237, an abnormality occurs in the second indoor unit 30, and no abnormality occurs in the first indoor unit 20 itself. When the first indoor unit 20 and the second indoor unit 30 are provided in different rooms as in the above embodiment, even if a refrigerant leak occurs in the second indoor unit 30, there is little need to perform an abnormality suppression operation in the first indoor unit 20. Also, if an abnormality suppression operation such as rotation at the maximum rotation speed of the fan 211 in the first indoor unit 20 is performed, there is a risk of causing discomfort to the user.

[0163] Therefore, when a specified electrical signal is input from the short circuit detection circuit 236 to the control circuit 237, but a specified electrical signal is not input from the abnormality detection circuit 233 to the control circuit 237, the control circuit 237 may cause the operation unit 21 to perform only the abnormality notification operation, and not to perform the abnormality suppression operation.

[0164] With this configuration, in a device in the refrigeration system 10 where an abnormality has occurred (for example, the second indoor unit 30), both the abnormality suppression operation and the abnormality notification operation are performed as protective operations, while in a device where no abnormality has occurred (for example, the first indoor unit 20), only the abnormality notification operation is performed as protective operations. This makes it possible to notify the user of an abnormality in the refrigeration system 10 more quickly while suppressing discomfort to the user using the first indoor unit 20. Note that the outdoor unit 40 may perform the abnormality suppression operation even if no abnormality has occurred in the outdoor unit 40 itself.

[0165] [Other variations] In the above embodiment, the refrigerant piping 50 directly connects the first indoor unit 20 and the second indoor unit 30. However, the refrigerant piping 50 only needs to have a function of circulating the refrigerant to the first indoor unit 20 and the second indoor unit 30, and the first indoor unit 20 and the second indoor unit 30 do not have to be directly connected by the refrigerant piping 50. For example, another indoor unit (or outdoor unit) or a branch unit for branching the refrigerant piping 50 may be inserted between the first indoor unit 20 and the second indoor unit 30, and the refrigerant piping 50 may be connected to the first indoor unit 20 and the second indoor unit 30 via the other indoor unit. In this case, the refrigerant piping 50 is not provided between the first indoor unit 20 and the second indoor unit 30, but the refrigerant piping 50 can circulate the refrigerant to the first indoor unit 20 and the second indoor unit 30 via the other indoor unit. Similarly, the refrigerant piping 50 only needs to have the function of circulating the refrigerant through the first indoor unit 20 and the outdoor unit 40, and the first indoor unit 20 and the outdoor unit 40 do not need to be directly connected by the refrigerant piping 50.

[0166] At least some of the above-described embodiments may be combined with each other in any desired manner.

[0167] [Effects of the embodiment] (1) The refrigeration system 10, 10a of the above embodiment and modified example includes a first device 20, 80, a second device 20, 30, 40, 80 communicatively connected to the first device 20, 80 via a first electric wire 60 and a second electric wire 70, and a refrigerant piping 50 that circulates a refrigerant through the first device 20, 80 or the second device 20, 30, 40, 80, wherein the first device 20, 80 has a first circuit 231, 831 that short-circuits the first electric wire 60 and the second electric wire 70 when an abnormality related to refrigerant leakage is detected, and the second device 20, 30, 40, 80 has a second circuit 232, 332, 432, 832 that initiates protective operation against the abnormality when the first electric wire 60 and the second electric wire 70 are short-circuited.

[0168] According to the refrigeration system 10, 10a, by shorting the first electric wire 60 and the second electric wire 70 used for communication between the first device 20, 80 and the second device 20, 30, 40, 80, the abnormality detected by the first device 20, 80 can be transmitted more quickly to the second device 20, 30, 40, 80. This makes it possible to hasten the start of protective action against the abnormality.

[0169] (2) In the refrigeration systems 10, 10a of the above-described embodiments and variations, the first circuit 231, 831 includes an abnormality detection circuit 233, 833 that detects an abnormality related to refrigerant leakage, and a switch 234, 834 connected in parallel to the first electric wire 60 and the second electric wire 70, and has a short-circuit 235, 835 that switches the switch 234, 834 from an open state to a connected state when the abnormality detection circuit 233, 833 detects an abnormality related to refrigerant leakage.

[0170] (3) In the refrigeration systems 10, 10a of the above embodiment and modified examples, the abnormality detection circuits 233, 833 detect an abnormality based on a detection signal from the sensors 27, 87 that detect leakage of refrigerant.

[0171] (4) In the refrigeration systems 10, 10a of the above-mentioned embodiments and variations, the second circuit 232, 332, 432, 832 is electrically connected to a short circuit detection circuit 236, 336, 436, 836 that detects a short circuit between the first electric wire 60 and the second electric wire 70, and an operation unit 21, 31, 41, 81 that performs protective operation against abnormalities, and has a control circuit 237, 337, 437, 837 that controls the operation unit 21, 31, 41, 81 when the short circuit detection circuit 236, 336, 436, 836 detects a short circuit between the first electric wire 60 and the second electric wire 70, and the second circuit 232, 332, 432, 832 is composed only of hardware.

[0172] According to the refrigeration system 10, 10a, the second circuit 232, 332, 432, 832 that starts the protective operation of the second device 20, 30, 40, 80 is configured only with hardware, so that errors caused by software, for example, can be avoided. This makes it possible to start the protective operation more reliably.

[0173] (5) In the refrigeration system 10 of the above embodiment, the first device 20 is the first indoor unit 20, and the second device 30, 40 is the second indoor unit 30 or the outdoor unit 40.

[0174] (6) In the refrigeration system 10a of the above-mentioned modified example, the first device 20, 80 is either the first indoor unit 20 or a remote controller 80 having an input section 812 for controlling the first indoor unit 20, and the second device 20, 80 is the other of the first indoor unit 20 or the remote controller 80.

[0175] (7) In the refrigeration systems 10, 10a of the above-described embodiments and variations, the second device 20, 30, 40, 80 further has a third circuit 231, 331, 431, 831 that short-circuits the first electric wire 60 and the second electric wire 70 when an abnormality related to refrigerant leakage is detected, and the first device 20, 80 further has a fourth circuit 232, 832 that initiates protective operation of the first device 20, 80 when the first electric wire 60 and the second electric wire 70 are short-circuited.

[0176] By shorting the first electric wire 60 and the second electric wire 70 used for communication between the first device 20, 80 and the second device 20, 30, 40, 80, an abnormality in the second device 20, 30, 40, 80 can be transmitted more quickly to the first device 20, 80. This makes it possible to hasten the start of protective operation of the first device 20, 80.

[0177] (8) In the above-mentioned embodiment and modified example of the refrigeration system 10, 10a, the first device 20, 80 has a protection board 23, 83 including a first circuit 231, 831 and a fourth circuit 232, 832, and a control board 22, 82 that is provided separately from the protection board 23, 83 and controls the operation of the first device 20, 80.

[0178] By providing the protection boards (23, 83) separately from the control boards (22, 82), even if an abnormality occurs in the control boards (22, 82), the protection operation can be performed more reliably.

[0179] (9) In the above-mentioned embodiment and modified example of the refrigeration system 10, 10a, the first device 20, 80 has a protection board 23, 83 including a first circuit 231, 831, and a control board 22, 82 that is provided separately from the protection board 23, 83 and controls the operation of the first device 20, 80.

[0180] By providing the protection boards (23, 83) separately from the control boards (22, 82), even if an abnormality occurs in the control boards (22, 82), the protection operation can be performed more reliably.

[0181] Although the embodiments have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the claims. [Explanation of symbols]

[0182] 10: refrigeration system, 10a: refrigeration system, 20: first indoor unit (an example of a first device or a second device), 21: operation unit, 211: fan, 212: heat exchanger, 213: display unit, 22: control board, 221: control unit, 222: communication unit, 23: protection board, 231: first circuit, 232: fourth circuit, 233: abnormality detection circuit, 234: switch, 235: short circuit, 236: short circuit detection circuit, 237: control circuit, 24: terminal block, 241: first terminal, 242: second terminal, 25: housing, 26: remote controller, 261: display unit, 262: Input unit, 27: sensor, 30: second indoor unit (an example of a second device), 31: operation unit, 311: fan, 312: heat exchanger, 313: display unit, 32: control board, 321: control unit, 322: communication unit, 33: protection board, 331: third circuit, 332: second circuit, 333: abnormality detection circuit, 334: switch, 335: short circuit, 336: short circuit detection circuit, 337: control circuit, 34: terminal block, 341: first terminal, 342: second terminal, 35: housing, 36: remote controller, 361: display unit, 362: input unit, 37: sensor, 40: outdoor unit (an example of the second device), 40a: outdoor unit (an example of the first device or the second device), 41: operating section, 411: fan, 412: heat exchanger, 413: compressor, 42: control board, 421: control section, 422: communication section, 43: protection board, 431: third circuit, 432: second circuit, 433: abnormality detection circuit, 434: switch, 435: short circuit, 436: short circuit detection circuit, 437: control circuit, 44: terminal block, 441: first terminal, 442: second terminal, 45: housing, 47: sensor, 50: refrigerant piping, 60: first electric wire, 61a: first region, 61b: second region area, 61c: first area, 61d: second area, 61e: third area, 61: external area, 62,64,66: internal area, 63: electric wire, 65: electric wire, 67: electric wire, 68: external area, 69: external area, 601: internal area, 602: electric wire, 70: second electric wire, 71a: first area , 71b: second area, 71c: first area, 71d: second area, 71e: third area, 71: external area, 72,74,76: internal area, 73: electric wire, 75: electric wire, 77: electric wire, 78: external area, 79: external area, 701: internal area, 702: electric wire, 80a,80b,80c: remote controller, 80: remote controller, 81: operation unit, 811: display unit, 812: input unit, 82: control board, 821: control unit, 822: communication unit, 83: protection board, 831: third circuit, 832: second circuit, 833: abnormality detection circuit, 834: switch, 835: short circuit, 836: short circuit detection circuit, 837: control circuit, 84: terminal block, 841: first terminal, 842: second terminal, 85: housing, 87: sensor, S11: indoor space, S12: ceiling space, S21: indoor space, S22: ceiling space, S31: outdoor space, t1: first time, t2: second time, t3: first time, t4: second time, D1: device, D2: device,

Claims

1. A first device (20, 80); A second device (20, 30, 40, 80) communicatively connected to the first device (20, 80) via a first electric wire (60) and a second electric wire (70); a refrigerant pipe (50) for circulating a refrigerant through the first device (20, 80) or the second device (20, 30, 40, 80); Equipped with The first device (20, 80) has a first circuit (231, 831) that short-circuits the first electric wire (60) and the second electric wire (70) when an abnormality related to leakage of a refrigerant is detected, The second device (20, 30, 40, 80) has a second circuit (232, 332, 432, 832) that starts a protective operation against an abnormality when the first electric wire (60) and the second electric wire (70) are short-circuited. A refrigeration system (10, 10a).

2. The first circuit (231, 831) is An abnormality detection circuit (233, 833) that detects an abnormality related to a leakage of a refrigerant; a short circuit (235, 835) including a switch (234, 834) connected in parallel to the first electric wire (60) and the second electric wire (70), which switches the switch (234, 834) from an open state to a connected state when the abnormality detection circuit (233, 833) detects an abnormality related to refrigerant leakage; Refrigeration system (10, 10a) according to claim 1, comprising:

3. 3. The refrigeration system according to claim 2, wherein the abnormality detection circuit detects an abnormality related to a refrigerant leak based on a detection signal of a sensor that detects a refrigerant leak.

4. The second circuit (232, 332, 432, 832) is a short circuit detection circuit (236, 336, 436, 836) for detecting a short circuit between the first electric wire (60) and the second electric wire (70); a control circuit (237, 337, 437, 837) electrically connected to an operating unit (21, 31, 41, 81) that performs a protective operation against an abnormality, and that controls the operating unit (21, 31, 41, 81) when a short circuit between the first electric wire (60) and the second electric wire (70) is detected by the short circuit detection circuit (236, 336, 436, 836); having The second circuit (232, 332, 432, 832) is configured only with hardware. A refrigeration system (10, 10a) according to any one of claims 1 to 3.

5. The first device (20) is a first indoor unit (20), The second device (30, 40) is a second indoor unit (30) or an outdoor unit (40). A refrigeration system (10) according to any one of claims 1 to 4.

6. the first device (20, 80) is one of a first indoor unit (20) or a remote controller (80) having an input unit (812) for controlling the first indoor unit (20); The second device (20, 80) is the other of the first indoor unit (20) or the remote controller (80). A refrigeration system (10a) according to any one of claims 1 to 4.

7. the second device (20, 30, 40, 80) further includes a third circuit (231, 331, 431, 831) that short-circuits the first electric wire (60) and the second electric wire (70) when an abnormality related to leakage of a refrigerant is detected; The first device (20, 80) further includes a fourth circuit (232, 832) that initiates a protective operation of the first device (20, 80) when the first electric wire (60) and the second electric wire (70) are short-circuited. A refrigeration system (10, 10a) according to any one of claims 1 to 6.

8. The first device (20, 80) is a protection substrate (23, 83) including the first circuit (231, 831) and the fourth circuit (232, 832); a control board (22, 82) provided separately from the protection board (23, 83) and controlling the operation of the first device (20, 80); having 8. A refrigeration system (10, 10a) according to claim 7.

9. The first device (20, 80) is A protection substrate (23, 83) including the first circuit (231, 831); a control board (22, 82) provided separately from the protection board (23, 83) and controlling the operation of the first device (20, 80); having A refrigeration system (10, 10a) according to any one of claims 1 to 7.

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