Refrigeration system

Abstract

A refrigeration system (10) is provided with: a first device (20); a second device (30) communicably connected to the first device (20) via a first electric wire (60) and a second electric wire (70); and a refrigerant pipe (50) circulating a refrigerant in the first device (20) or the second device (30), the first device (20) having a first circuit (231) short-circuiting the first electric wire (60) and the second electric wire (70) when detecting an abnormality related to a refrigerant leakage, the second device (30) having a second circuit (332) starting a protection action against the abnormality when the first electric wire (60) and the second electric wire (70) are short-circuited.

Description

TECHNICAL FIELD

[0001] The present application relates to a refrigeration system. BACKGROUND

[0002] A refrigeration system is known, which has an indoor unit and an outdoor unit, and performs air conditioning or refrigeration by heat exchange using a refrigerant. In the refrigeration system, a protection action is required in a case where the refrigerant leaks outside the refrigeration system.

[0003] For example, in Patent Literature 1, it is determined whether or not there is a refrigerant leak based on a measured value of a refrigerant detection device provided in the indoor unit. In a case where it is determined that there is a refrigerant leak, the rotation speed of an indoor blower is controlled to a rotation speed greater than the maximum rotation speed at the time of normal operation, or the operation of a compressor mounted on the outdoor unit is stopped.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: International Publication No. 2017 / 175300 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] Conventionally, an indoor control device that controls the indoor unit and an outdoor control device that controls the outdoor unit are connected by a transmission line (communication line), and can perform transmission and reception of information. Therefore, conventionally, in a case where an abnormality occurs in the indoor unit, the abnormality of the indoor unit is transmitted to the outdoor control device through the transmission line, and thereby the compressor mounted on the outdoor unit and the like are stopped.

[0009] In order to improve the safety of a refrigeration system including a plurality of devices (for example, an indoor unit and an outdoor unit), it is necessary to transmit an abnormality more quickly to a second device (for example, an outdoor unit) different from a first device (for example, an indoor unit) after the abnormality is detected in the first device.

[0010] An object of the present disclosure is to provide a refrigeration system capable of transmitting an abnormality more quickly.

[0011] MEANS FOR SOLVING THE PROBLEMS

[0012] (1) The refrigerant system of the present disclosure includes a first device, a second device communicatively connected to the first device via a first electric line and a second electric line, and a refrigerant pipe that circulates refrigerant in the first device or the second device, the first device having a first circuit that shorts the first electric line and the second electric line when an abnormality related to a refrigerant leak is detected, and the second device having a second circuit that starts a protection action against the abnormality when the first electric line and the second electric line are shorted.

[0013] According to the refrigerant system of the present disclosure, an abnormality detected by the first device can be more quickly transmitted to the second device side by shorting the first electric line and the second electric line used in communication between the first device and the second device. Thus, the start of the protection action against the abnormality can be advanced.

[0014] (2) Preferably, the first circuit includes an abnormality detection circuit that detects an abnormality related to a refrigerant leak, and a shorting circuit that includes a switch connected in parallel to the first electric line and the second electric line, the switch being switched from an open state to a connected state when an abnormality related to a refrigerant leak is detected by the abnormality detection circuit.

[0015] (3) Preferably, the abnormality detection circuit detects an abnormality based on a detection signal of a sensor that detects a refrigerant leak.

[0016] (4) Preferably, the second circuit includes a shorting detection circuit that detects shorting of the first electric line and the second electric line, and a control circuit that is electrically connected to an action section that performs a protection action against an abnormality, the control circuit controlling the action section when shorting of the first electric line and the second electric line is detected by the shorting detection circuit, the second circuit being composed only of hardware.

[0017] By composing the second circuit that starts the protection action of the second device only of hardware, it is possible to avoid, for example, an error due to software. Thus, it is possible to more reliably start the protection action.

[0018] (5) Preferably, the first device is a first indoor unit, and the second device is a second indoor unit or an outdoor unit.

[0019] (6) The first device is one of a first indoor unit and a remote controller that has an input section for controlling the first indoor unit, and the second device is the other of the first indoor unit and the remote controller.

[0020] (7) Preferably, the second device further has a third circuit which shorts the first electric line and the second electric line when an abnormality of the second device is detected, and the first device further has a fourth circuit which starts a protection action of the first device when the first electric line and the second electric line are shorted.

[0021] By shorting the first electric line and the second electric line used in the communication between the first device and the second device, an abnormality of the second device can be more quickly transmitted to the first device side. Thereby, the start of the protection action of the first device can be advanced.

[0022] (8) Preferably, the first device has a protection substrate which includes the first circuit and the fourth circuit, and a control substrate which is provided separately from the protection substrate and controls an action of the first device.

[0023] By providing the protection substrate and the control substrate separately, the protection action can be more reliably performed even in a case where an abnormality has occurred in the control substrate.

[0024] (9) Preferably, the first device has a protection substrate which includes the first circuit, and a control substrate which is provided separately from the protection substrate and controls an action of the first device.

[0025] By providing the protection substrate and the control substrate separately, the protection action can be more reliably performed even in a case where an abnormality has occurred in the control substrate. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a diagram which schematically shows the structure of a refrigeration system of the embodiment.

[0027] Figure 2 is a diagram which schematically shows the internal structure of the first indoor unit of the embodiment.

[0028] Figure 3 is a diagram which schematically shows the internal structure of the second indoor unit of the embodiment.

[0029] Figure 4 is a diagram which schematically shows the internal structure of the outdoor unit of the embodiment.

[0030] Figure 5 is a flowchart which shows an example of the protection method of the embodiment.

[0031] Figure 6 is a flowchart which shows an example of the protection method of the embodiment.

[0032] Figure 7 is a diagram which schematically shows the outdoor unit of the modification.

[0033] Figure 8 FIG. 1 is a diagram schematically showing a structure of a refrigeration system according to an embodiment of the present disclosure.

[0034] Figure 9 FIG. 2 is a diagram schematically showing an internal structure of a remote controller according to an embodiment of the present disclosure.

[0035] Figure 10 FIG. 3 is a diagram schematically showing a first electric wire and a second electric wire according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0036] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0037] [EMBODIMENT]

[0038] [Outline of refrigeration system]

[0039] The refrigeration system 10 of the embodiment more promptly transmits an abnormal state to other devices (for example, the outdoor unit 40) connected to the first electric wire 60 and the second electric wire 70 by short-circuiting the first electric wire 60 and the second electric wire 70 used as communication lines when the first indoor unit 20 or the second indoor unit 30 becomes an abnormal state.

[0040] [Overall structure of refrigeration system]

[0041] Figure 1 FIG. 1 is a diagram schematically showing a structure of a refrigeration system according to an embodiment of the present disclosure.

[0042] Figure 2 FIG. 2 is a diagram schematically showing an internal structure of a remote controller according to an embodiment of the present disclosure.

[0043] Figure 3 FIG. 3 is a diagram schematically showing a first electric wire and a second electric wire according to an embodiment of the present disclosure.

[0044] Figure 4 FIG. 4 is a diagram schematically showing an internal structure of an outdoor unit 40 according to an embodiment of the present disclosure.

[0045] REFERENCE Figure 1 .

[0046] The refrigeration system 10 is a system that performs heat exchange via a refrigerant. The refrigeration system 10 is, for example, an air conditioning device for adjusting the temperature of an indoor space, a freezing device for freezing and preserving food, or a refrigerating device for refrigerating and preserving food. In the present embodiment, the refrigeration system 10 as an air conditioning device is representatively described.

[0047] The refrigeration system 10 has a first indoor unit 20, a second indoor unit 30, an outdoor unit 40, a refrigerant pipe 50, a first electric wire 60, and a second electric wire 70. The first indoor unit 20 is an example of the "first device" of the present disclosure. The second indoor unit 30 is an example of the "second device" of the present disclosure. The outdoor unit 40 is an example of the "second device" of the present disclosure. The refrigeration system 10 can also have an indoor unit other than the first indoor unit 20 and the second indoor unit 30.

[0048] The first indoor unit 20 has a function of adjusting the temperature of an indoor space S11. The first indoor unit 20 is, for example, a ceiling recessed type indoor unit. A housing 25 described later, which is included in the first indoor unit 20, is housed in a ceiling back space S12 located above the indoor space S11. In addition, the first indoor unit 20 can also be a ceiling suspended type, a floor fixed type, or a wall mounted type indoor unit. In this case, the housing 25 is provided in the indoor space S11.

[0049] The second indoor unit 30 has a function of adjusting the temperature of an indoor space S21. The indoor space S21 is a space located in a different room from the indoor space S11. The second indoor unit 30 is, for example, a ceiling recessed type indoor unit. A housing 35 described later, which is included in the second indoor unit 30, is housed in a ceiling back space S22 located above the indoor space S21. In addition, the second indoor unit 30 can also be a ceiling suspended type, a floor fixed type, or a wall mounted type indoor unit. In this case, the housing 35 is provided in the indoor space S21.

[0050] The outdoor unit 40 is provided in an outdoor space S31.

[0051] The refrigerant pipe 50 is a pipe for circulating a refrigerant. The refrigerant pipe 50 is connected to a heat exchanger 212 described later of the first indoor unit 20, a heat exchanger 312 described later of the second indoor unit 30, and a heat exchanger 412 described later of the outdoor unit 40, and circulates the refrigerant in each of the heat exchangers 212, 312, 412.

[0052] 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 have a function as communication lines that communicably connect the first indoor unit 20, the second indoor unit 30, and the outdoor unit 40, respectively.

[0053] Specifically, the 1st indoor unit 20 communicates with the 2nd indoor unit 30 and the outdoor unit 40 by outputting a communication signal to the 1st electric wire 60 and the 2nd electric wire 70. The 2nd indoor unit 30 communicates with the 1st indoor unit 20 and the outdoor unit 40 by outputting a communication signal to the 1st electric wire 60 and the 2nd electric wire 70. The outdoor unit 40 communicates with the 1st indoor unit 20 and the 2nd indoor unit 30 by outputting a communication signal to the 1st electric wire 60 and the 2nd electric wire 70.

[0054] As shown in FIG. 1, the 1st electric wire 60 has an outer region 61 and three inner regions 62, 64, 66. The outer region 61 is a region connecting between the 1st terminals 241, 341, 441 described later. The three inner regions 62, 64, 66 are regions connecting the 1st terminals 241, 341, 441 and the control boards 22, 32, 42 described later, respectively. Figures 1 to 4

[0055] As shown in FIG. 2, the 2nd electric wire 70 has an outer region 71 and three inner regions 72, 74, 76. The outer region 71 is a region connecting between the 2nd terminals 242, 342, 442 described later. The three inner regions 72, 74, 76 are regions connecting the 2nd terminals 242, 342, 442 and the control boards 22, 32, 42 described later, respectively. Figures 1 to 4

[0056] In the present embodiment, two electric wires (the 1st electric wire 60 and the 2nd electric wire 70) are used as the communication lines. However, three or more electric wires can be used as the communication lines. In this case, any two of the three or more electric wires are referred to as the 1st electric wire 60 and the 2nd electric wire 70.

[0057] [Structure of 1st indoor unit]

[0058] Referring to FIG. 3, the 1st indoor unit 20 has an operation portion 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 operation portion 21, the control board 22, the protection board 23, and the terminal block 24 are housed in the housing 25. Figure 1 Figure 2 The remote controller 26 and the sensor 27 are provided outside the housing 25. In the present embodiment, the remote controller 26 and the sensor 27 are provided in the indoor space S11. In addition, the sensor 27 can be provided in the ceiling back space S12 or in the housing 25.

[0059] The remote controller 26 and the sensor 27 are provided outside the housing 25. In the present embodiment, the remote controller 26 and the sensor 27 are provided in the indoor space S11. In addition, the sensor 27 can be provided in the ceiling back space S12 or in the housing 25.

[0060] The remote controller 26 and the sensor 27 are provided outside the housing 25. In the present embodiment, the remote controller 26 and the sensor 27 are provided in the indoor space S11. In addition, the sensor 27 can be provided in the ceiling back space S12 or in the housing 25.

[0061] ​​​The remote controller 26 is connected to the control substrate 22 and the protection substrate 23 by wire or wirelessly. The remote controller 26 has a display portion 261 and an input portion 262. The display portion 261 includes, for example, an LED, a liquid crystal panel. The display portion 261 displays the state of the air conditioning system 10 (for example, the current set temperature, the air volume, the air direction, the content of the error generated in the air conditioning system 10, and the like) to the user according to the instruction of the control portion 221 or the control circuit 237 described later. The input portion 262 includes a button for the user to set the temperature, the air volume, the air direction, and the like. The input portion 262 transmits the input received from the user to the control substrate 22 or the protection substrate 23.

[0062] The operation portion 21 has a fan 211, a heat exchanger 212, a display portion 213, a first air exchange device (omitted from the drawing), and a first shutoff valve (omitted from the drawing). The fan 211 and the heat exchanger 212 are housed in the casing 25. The display portion 213 is housed in the casing 25 in a state in which the user in the indoor space S11 can see the display. The first air exchange device and the first shutoff valve are provided outside the casing 25.

[0063] The fan 211 takes in the air in the indoor space S11 into the casing 25, and supplies the air (conditioned air) in which heat exchange has been performed in the heat exchanger 212 to the indoor space S11 in the casing 25. The heat exchanger 212 is, for example, a cross finned tube type heat exchanger. The heat exchanger 212 is connected to the refrigerant pipe 50.

[0064] The display portion 213 includes, for example, an LED, a liquid crystal panel, and displays the state of the air conditioning system 10 to the user. For example, the display portion 213 can make a green LED light up in order to display normal operation, and can make a yellow LED blink in order to display an error of the air conditioning system 10. In addition, the display portion 213 can make the liquid crystal panel display the state of the first indoor unit 20.

[0065] The first air exchange device (omitted from the drawing) is a device for discharging the air in the indoor space S11 to the outdoor space S31, and has a fan. The first air exchange device is provided, for example, on a wall that separates the indoor space S11 from the outdoor space S31.

[0066] The first shutoff valve (omitted from the drawing) is, for example, a valve that controls the flow of the refrigerant pipe 50 on the upstream side of the heat exchanger 212. The first shutoff valve is normally open, and the refrigerant flows from the refrigerant pipe 50 to the heat exchanger 212. When the first shutoff valve is closed, the heat exchanger 212 is separated from the refrigerant pipe 50, and the flow of the refrigerant from the refrigerant pipe 50 to the first indoor unit 20 is stopped. The first shutoff valve is provided, for example, in the ceiling back space S12.

[0067] The terminal block 24 is a member for connecting the first electric wire 60 and the second electric wire 70 to each part in the casing 25. The terminal block 24 has a first terminal 241 and a second terminal 242. The first electric wire 60 is connected to the first terminal 241. The second electric wire 70 is connected to the second terminal 242.

[0068] The control substrate 22 is a substrate that controls the usual operation of the first indoor unit 20, and has a control section 221 and a communication section 222. A microprocessor or the like arithmetic processing device and a memory IC or the like storage device are mounted on the control substrate 22. The control section 221 and the communication section 222 are realized by the arithmetic processing device reading out a program stored in advance in the storage device.

[0069] The first electric wire 60 and the second electric wire 70 are connected to the control substrate 22. Specifically, the first electric wire 60 (the internal region 62) is connected between the first terminal 241 and the control substrate 22, and the second electric wire 70 (the internal region 72) is connected between the second terminal 242 and the control substrate 22. The communication signal flowing in the first electric wire 60 and the second electric wire 70 is input to the communication section 222.

[0070] The control section 221 controls the operation of the operation section 21 on the basis of a program stored in advance and information input from the communication section 222. The control section 221, for example, controls the rotation speed of the fan 211 and the display of the display section 213. In addition, the control section 221 controls the display of the display section 261 included in the remote controller 26.

[0071] The communication section 222 communicates with other devices included in the refrigeration system 10 (for example, the second indoor unit 30, the outdoor unit 40). The communication section 222 converts the communication signal constituted by the potential difference of the first electric wire 60 and the second electric wire 70 into a digital signal, and delivers it to the control section 221 as information input from the other devices. In addition, the communication section 222 converts the digital signal output from the control section 221 into a communication signal, and outputs it to the first electric wire 60 and the second electric wire 70.

[0072] The protection substrate 23 is a substrate provided separately from the control substrate 22, and controls the operation for protecting the first indoor unit 20. The protection substrate 23 has a first circuit 231 and a fourth circuit 232. The first circuit 231 and the fourth circuit 232 do not include an arithmetic processing device such as a microprocessor, and are constituted only by hardware.

[0073] The first circuit 231 is a circuit that shorts the first electric wire 60 and the second electric wire 70 when an abnormality of the first indoor unit 20 is detected. The first circuit 231 has an abnormality detection circuit 233 and a shorting circuit 235.

[0074] The abnormality detection circuit 233 is a circuit for detecting an abnormality related to a leakage of refrigerant. The abnormality detection circuit 233 is electrically connected to the sensor 27, the short-circuiting circuit 235, and the control circuit 237. The abnormality detection circuit 233 detects an abnormality related to a leakage of refrigerant on the basis of a detection signal of the sensor 27. The structure of the sensor 27 is described later.

[0075] As the abnormality related to a leakage of refrigerant, for example, a leakage of refrigerant from the refrigerant pipe 50, a failure of the sensor 27 for detecting a leakage of refrigerant, the sensor 27 reaching a lifetime, and the like can be given. The abnormality detection circuit 233 outputs a prescribed electric signal to the short-circuiting circuit 235 and the control circuit 237 when detecting an abnormality related to a leakage of refrigerant.

[0076] The short-circuiting circuit 235 has the electric wire 63, the electric wire 73, and the 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. In addition, one end of the electric wire 63 can be connected to the internal 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. In addition, one end of the electric wire 73 can be connected to the internal region 72 of the second electric wire 70. By thus constituting, 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.

[0077] The switch 234 is set to an open state. When the abnormality detection circuit 233 detects an abnormality related to a leakage of refrigerant, a prescribed electric signal is input from the abnormality detection circuit 233 to the short-circuiting circuit 235. On the basis of the prescribed electric signal, the switch 234 is switched from the open state to the connected state. Thus, the first electric wire 60 and the second electric wire 70 are electrically connected with a lower resistance than in normal times via the electric wire 63, the switch 234, and the electric wire 73 (the first electric wire 60 and the second electric wire 70 are short-circuited by the short-circuiting circuit 235).

[0078] Further, the electric wire 63 and the electric wire 73 can include a resistance element having a low resistance. Even in the case of thus constituting, if 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, "short-circuited" includes a case where the first electric wire 60 and the second electric wire 70 are electrically connected via a resistance element having a low resistance in addition to a case where the first electric wire 60 and the second electric wire 70 are electrically connected with a resistance substantially close to zero. In any case, a large current that does not flow in normal communication flows between the first electric wire 60 and the second electric wire 70.

[0079] The fourth circuit 232 is a circuit that starts a protection operation of the first indoor unit 20 when the first electric wire 60 and the second electric wire 70 are short-circuited. The fourth circuit 232 has a short-circuiting detection circuit 236 and a control circuit 237.

[0080] The short-circuit detection circuit 236 is a circuit that detects a short-circuit of the first electric wire 60 and the second electric wire 70. One end of the short-circuit detection circuit 236 is connected to the electric wire 63, and the other end is connected to the electric wire 73. Alternatively, one end of the short-circuit detection circuit 236 can be connected to the internal region 62 of the first electric wire 60, and the other end can be connected to the internal region 72 of the second electric wire 70. Further, the short-circuit detection circuit 236 is electrically connected to the control circuit 237.

[0081] The short-circuit detection circuit 236 detects, for example, a potential difference between the first electric wire 60 and the second electric wire 70. Further, in a case where the potential difference continues to be lower than a prescribed lower limit value for a prescribed time (for example, for longer than a 0V output time in a normal communication signal), it is considered that the first electric wire 60 and the second electric wire 70 are short-circuited, and a prescribed electric signal is output to the control circuit 237.

[0082] Further, the short-circuit detection circuit 236 can also be a circuit that detects a current value of at least one of the first electric wire 60 and the second electric wire 70 (an overcurrent detection circuit). In this case, the short-circuit detection circuit 236 has a current sensor that is inserted into at least one of the first electric wire 60 and the second electric wire 70. Further, in a case where the current value detected by the current sensor exceeds a prescribed upper limit value, it is considered that the first electric wire 60 and the second electric wire 70 are short-circuited, and a prescribed electric signal is output to the control circuit 237.

[0083] The control circuit 237 is electrically connected to the operation portion 21. When the short-circuit detection circuit 236 detects a short-circuit of the first electric wire 60 and the second electric wire 70, a prescribed electric signal is input from the short-circuit detection circuit 236 to the control circuit 237. When the prescribed electric signal is input, the control circuit 237 controls the operation portion 21 so that the operation portion 21 performs a protection operation against an abnormality.

[0084] The protection operation performed by the operation portion 21 includes 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 or preventing the abnormal state of the refrigeration system 10 from further deteriorating. The abnormality notification operation includes an operation for notifying a user of an abnormality of the refrigeration system 10.

[0085] The abnormality suppression operation includes rotating the fan 211 at a maximum rotational speed. Further, the abnormality suppression operation includes operating the first air-exchange device (not shown) with a maximum air volume. By these operations, it is possible to quickly diffuse the leaked refrigerant and prevent a local increase in the refrigerant concentration. The rotation of the fan 211 and the operation of the first air-exchange device can be continued for a predetermined time, or can be continued until the abnormality detection circuit 233 no longer detects an abnormality.

[0086] In a case where the abnormality suppression action includes rotation of the fan 211 or the operation of the first air ventilator, the abnormality suppression action can also include stopping the acceptance of input from the input section 262 of the remote controller 26. In this case, even if input is made to the input section 262, the input is not transmitted to the control section 221. With this action, it is possible to avoid a case where the other protection action such as rotation of the fan 211 is stopped earlier than the preset time.

[0087] Further, in a case where the acceptance of input from the input section 262 is stopped, it is also possible to perform display of "input impossible" or the like on the display section 261 of the remote controller 26 when the user presses the button included in the input section 262 in order to convey to the user that the input is invalid.

[0088] The abnormality suppression action includes closing the first shutoff valve (not shown) provided to the refrigerant pipe 50. With this action, the inflow of refrigerant from the refrigerant pipe 50 to the first indoor unit 20 is stopped, and thus it is possible to suppress further leakage of refrigerant.

[0089] The abnormality notification action includes causing the display section 213 to display the refrigerant leakage by light or sound. In this case, it is possible to cause the LED included in the display section 213 to blink by a color different from that during normal operation (for example, yellow, red), to cause the liquid crystal panel included in the display section 213 to display that the leakage of refrigerant has occurred by characters, or to generate a warning sound from the speaker included in the display section 213.

[0090] The abnormality notification action includes causing the display section 261 of the remote controller 26 to display the refrigerant leakage by light or sound. With these actions, it is possible to notify the user of the refrigerant leakage.

[0091] The sensor 27 is a sensor that detects the leakage of refrigerant. 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 refrigerant and outputs the detected refrigerant concentration to the abnormality detection circuit 233 as a detection signal. For example, the detection signal of the sensor 27 exceeding a prescribed upper limit value means that the refrigerant exceeds a prescribed concentration and leakage has occurred. Therefore, in a case where a detection signal exceeding the prescribed upper limit value is input from the sensor 27 to the abnormality detection circuit 233, the abnormality detection circuit 233 detects the abnormality of refrigerant leakage.

[0092] In addition, the case where the detection signal of the sensor 27 is below the prescribed lower limit value for a prescribed time (for example, the value of the detection signal of the sensor 27 becomes zero) means that the sensor 27 has failed to perform accurate output. Therefore, in the case where a detection signal below the prescribed lower limit value is input from the sensor 27 to the abnormality detection circuit 233 (or in the case where no detection signal is input), the abnormality detection circuit 233 detects a failure of the sensor 27.

[0093] The sensor 27 can be a sensor that directly detects the concentration of the refrigerant, or can be a sensor that indirectly detects the concentration of the refrigerant. As a sensor 27 that indirectly detects the concentration of the refrigerant, for example, a carbon dioxide sensor, an oxygen concentration sensor can be given. If a leak of the refrigerant occurs, the concentration of a gas that is normally contained in the air relatively decreases along with an increase in the concentration of the refrigerant in the air. Therefore, by detecting a decrease in the concentration of the gas that is normally contained in the air using the sensor 27, an increase in the concentration of the refrigerant is indirectly detected.

[0094] In the case of a sensor 27 that detects the concentration of oxygen, the detected oxygen concentration is output as a detection signal to the abnormality detection circuit 233. For example, the case where the detection signal of the sensor 27 is below the prescribed lower limit value means that the oxygen is below the prescribed concentration, and it is predicted that the refrigerant exceeds the prescribed concentration and a leak has occurred. Therefore, in the case where a detection signal below the prescribed lower limit value is input from the sensor 27 (oxygen concentration sensor) to the abnormality detection circuit 233, the abnormality detection circuit 233 detects an abnormality of a refrigerant leak.

[0095] In addition, the sensor 27 can also be a pressure sensor provided to 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. If a leak of the refrigerant occurs, the pressure of the refrigerant in the refrigerant pipe 50 decreases. Therefore, for example, in the case where the detection signal of the sensor 27 is below the prescribed lower limit value, it is considered that a refrigerant exceeding a prescribed amount has leaked from the refrigerant pipe 50, and the abnormality detection circuit 233 detects an abnormality of a refrigerant leak.

[0096] In addition, the abnormality detection circuit 233 can also internally incorporate a counter, for example. The counter counts the power-on time of the sensor 27 and the abnormality detection circuit 233 and records the cumulative value of the power-on time. Also, in the case where the cumulative value exceeds a prescribed upper limit value, it is considered that the life has been reached due to the aging of the sensor 27, and the abnormality detection circuit 233 detects an abnormality. In addition, for safety, the prescribed upper limit value can also be set to be shorter than the life caused by the aging of the actual sensor 27. In the case of replacement with a new sensor 27, the cumulative value of the power-on time in the counter of the abnormality detection circuit 233 is reset.

[0097] [Structure of the 2nd indoor unit]

[0098] Referring to Figure 1 and Figure 3 .

[0099] The 2nd indoor unit 30 has an operation part 31, a control substrate 32, a protection substrate 33, a terminal table 34, a housing 35, a remote controller 36, and a sensor 37. These structures are respectively the same as the operation part 21, the control substrate 22, the protection substrate 23, the terminal table 24, the housing 25, the remote controller 26, and the sensor 27 of the 1st indoor unit 20. As for the structures in the 2nd indoor unit 30 that are the same as those in the 1st indoor unit 20, the description is appropriately omitted.

[0100] In the present embodiment, the remote controller 36 and the sensor 37 are provided in the indoor space S21. In addition, the sensor 37 can be provided in the ceiling back space S22 or in the housing 35.

[0101] The remote controller 36 has a display part 361 and an input part 362. The display part 361 and the input part 362 have the same structures as the display part 261 and the input part 262.

[0102] The operation part 31 has a fan 311, a heat exchanger 312, a display part 313, a 2nd air exchange device (omitted from the drawing), and a 2nd shutoff valve (omitted from the drawing). These structures are respectively the same as the fan 211, the heat exchanger 212, the display part 213, the 1st air exchange device (omitted from the drawing), and the 1st shutoff valve (omitted from the drawing).

[0103] The fan 311 takes in the air in the indoor space S21 into the housing 35 and supplies the air, which has undergone heat exchange by the heat exchanger 312 in the housing 35, to the indoor space S21. The 2nd air exchange device (omitted from the drawing) is a device for discharging the air in the indoor space S21 to the outdoor space S31 and has a fan. The 2nd air exchange device is provided, for example, on a wall that separates the indoor space S21 from the outdoor space S31. The 2nd shutoff valve is provided, for example, in the ceiling back space S22.

[0104] The terminal table 34 has a 1st terminal 341 and a 2nd terminal 342. These structures are respectively the same as the 1st terminal 241 and the 2nd terminal 242.

[0105] The control substrate 32 is a substrate that controls the normal operation of the second indoor unit 30, and has a control section 321 and a communication section 322. These structures are the same as the control section 221 and the communication section 222, respectively. The first electric wire 60 and the second electric wire 70 are connected to the control substrate 32. Specifically, the first electric wire 60 (the internal region 64) is connected between a first terminal 341 and the control substrate 32, and the second electric wire 70 (the internal region 74) is connected between a second terminal 342 and the control substrate 32. The communication section 322 communicates with other devices included in the refrigeration system 10 (for example, the first indoor unit 20, the outdoor unit 40).

[0106] The protection substrate 33 has a third circuit 331 and a second circuit 332. The third circuit 331 and the second circuit 332 are composed of only hardware. The third circuit 331 is the same structure as the first circuit 231, and the second circuit 332 is the same structure as the fourth circuit 232.

[0107] The third circuit 331 has an abnormality detection circuit 333 and a short-circuiting circuit 335. The short-circuiting circuit 335 has the electric wire 65, the electric wire 75, and a switch 334. These structures are the same as the abnormality detection circuit 233, the short-circuiting circuit 235, the electric wire 63, the electric wire 73, and the switch 234, respectively.

[0108] The second circuit 332 is a circuit that starts the protection operation of the second indoor unit 30 when the first electric wire 60 and the second electric wire 70 are short-circuited. The second circuit 332 has a short-circuiting detection circuit 336 and a control circuit 337. These structures are the same as the short-circuiting detection circuit 236 and the control circuit 237, respectively.

[0109] [Structure of Outdoor Unit]

[0110] Reference Figure 1 and Figure 4 .

[0111] The outdoor unit 40 has an operation section 41, a control substrate 42, a protection substrate 43, a terminal block 44, and a casing 45. These structures are the same as the operation section 21, the control substrate 22, the protection substrate 23, the terminal block 24, and the casing 25 of the first indoor unit 20, respectively. Regarding the structures of the outdoor unit 40 that are the same as those of the first indoor unit 20, appropriate description is omitted.

[0112] The operation section 41 has a fan 411, a heat exchanger 412, and a third shut-off valve (omitted from illustration). These structures are the same as the fan 211, the heat exchanger 212, and the first shut-off valve (omitted from illustration), respectively. In addition, the operation section 41 has a compressor 413 that compresses refrigerant. The compressor 413 is connected to the refrigerant pipe 50.

[0113] The fan 411 takes in air of the outdoor space S31 into the casing 45, and discharges air, which has undergone heat exchange by the heat exchanger 412 in the casing 45, to the outdoor space S31. The 3rd shutoff valve is provided in the casing 45, for example.

[0114] The terminal block 44 has a 1st terminal 441 and a 2nd terminal 442. These structures are the same as the 1st terminal 241 and the 2nd terminal 242, respectively.

[0115] The control substrate 42 is a substrate that controls the general operation of the outdoor unit 40, and has a control section 421 and a communication section 422. These structures are the same as the control section 221 and the communication section 222, respectively. The 1st electric wire 60 and the 2nd electric wire 70 are connected to the control substrate 42. Specifically, the 1st electric wire 60 (the internal region 66) is connected between the 1st terminal 441 and the control substrate 42, and the 2nd electric wire 70 (the internal region 76) is connected between the 2nd terminal 442 and the control substrate 42. The communication section 422 communicates with other devices included in the refrigeration system 10 (for example, the 1st indoor unit 20 and the 2nd indoor unit 30).

[0116] The protection substrate 43 has a 2nd circuit 432. The 2nd circuit 432 is configured only by hardware. The 2nd circuit 432 is the same structure as the 4th circuit 232.

[0117] The 2nd circuit 432 is a circuit that starts the protection operation of the outdoor unit 40 when the 1st electric wire 60 and the 2nd electric wire 70 are short-circuited. The 2nd circuit 432 has a short-circuit detection circuit 436 and a control circuit 437.

[0118] The short-circuit detection circuit 436 is a circuit that detects short-circuiting of the 1st electric wire 60 and the 2nd electric wire 70. One end of the short-circuit detection circuit 436 is connected to the internal region 66, and the other end is connected to the internal region 76. In addition, the short-circuit detection circuit 436 is electrically connected to the control circuit 437.

[0119] The short-circuit detection circuit 436 detects a potential difference between the 1st electric wire 60 and the 2nd electric wire 70, for example. And, in a case where the potential difference continues to be lower than a prescribed lower limit value for a prescribed time, it is considered that the 1st electric wire 60 and the 2nd electric wire 70 are short-circuited, and a prescribed electric signal is output to the control circuit 437.

[0120] In addition, the short-circuit detection circuit 436 can also be a circuit that detects a current value of at least one of the 1st electric wire 60 and the 2nd electric wire 70 (an overcurrent detection circuit). In this case, in a case where the current value exceeds a prescribed upper limit value, it is considered that the 1st electric wire 60 and the 2nd electric wire 70 are short-circuited, and a prescribed electric signal is output to the control circuit 437.

[0121] The control circuit 437 is electrically connected to the operation section 41. When the short-circuit detection circuit 436 detects the short-circuit of the first electric wire 60 and the second electric wire 70, a prescribed electric signal is input from the short-circuit detection circuit 436 to the control circuit 437. When the prescribed electric signal is input, the control circuit 437 controls the operation section 41 so that the operation section 41 performs a protection operation against the abnormality.

[0122] The protection operation performed by the operation section 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 or preventing the abnormal state of the refrigeration system 10 from further deteriorating.

[0123] The abnormality suppression operation includes stopping the compressor 413. In addition, the abnormality suppression operation includes closing a third shut-off valve (not shown). By these operations, the circulation of the refrigerant in the refrigerant pipe 50 is stopped, and thus further leakage of the refrigerant can be suppressed.

[0124] In addition, the abnormality suppression operation includes applying interlocking to the outdoor unit 40 after the compressor 413 is stopped and the third shut-off valve is closed. In this case, as long as the prescribed input condition is not satisfied, the compressor 413 is not started and the third shut-off valve is not opened. By this operation, during the period in which the abnormal state such as the refrigerant leakage continues, it is possible to prevent the operation of the compressor 413 and the like from accidentally starting again.

[0125] [Protection method in refrigeration system]

[0126] Appropriate reference Figures 1 to 5 A protection method in the refrigeration system 10 will be described.

[0127] Figure 5 is a flowchart showing an example of the protection method in the refrigeration system 10.

[0128] First, the operation of the first indoor unit 20 will be described.

[0129] For example, consider a case in which the refrigerant leaks from a portion of the refrigerant pipe 50 (for example, a joint of the pipe) connected to the first indoor unit 20 to the ceiling back 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 prescribed upper limit value, the abnormality detection circuit 233 considers that the refrigerant exceeds a prescribed concentration, a leakage has occurred, and an abnormality related to the leakage of the refrigerant is detected, and outputs a prescribed electric signal to the short-circuit circuit 235 and the control circuit 237 (abnormality detection step ST21).

[0130] When a prescribed electric signal is input from the abnormality detection circuit 233 in the short-circuit 235, the switch 234 is switched from the open state to the connected state. Thereby, the first electric wire 60 is short-circuited with the second electric wire 70 (short-circuiting step ST22).

[0131] Next, the short-circuit detection circuit 236 detects the short-circuiting of the first electric wire 60 with the second electric wire 70, and outputs a prescribed electric signal to the control circuit 237 (short-circuit detection step ST23).

[0132] When the prescribed electric signal is input to the control circuit 237, the control circuit 237 causes the operation section 21 to perform a protection operation against the abnormality (protection operation step ST24).

[0133] Further, the control circuit 237 can also cause the operation section 21 to perform the protection operation against the abnormality at the time of the earlier one of when the prescribed electric signal is input from the abnormality detection circuit 233 and when the prescribed electric signal is input from the short-circuit detection circuit 236. By so configuring, in the first indoor unit 20 in which the abnormality has occurred, it is possible to perform the protection operation step ST24 immediately after the abnormality detection step ST21. Thereby, it is possible to omit the short-circuiting step ST22 and the short-circuit detection step ST23, and thus it is possible to start the protection operation against the abnormality more quickly.

[0134] Next, the operation of the second indoor unit 30 will be described.

[0135] The second indoor unit 30 is connected to the first electric wire 60 and the second electric wire 70. Therefore, if the first electric wire 60 and the second electric wire 70 are short-circuited at the first time tl by the above-described short-circuiting step ST22, the short-circuit detection circuit 336 of the second indoor unit 30 detects the short-circuiting of the first electric wire 60 with the second electric wire 70 at a second time t2 later than the first time tl, and outputs a prescribed electric signal to the control circuit 337 (short-circuit detection step ST31).

[0136] When the prescribed electric signal is input to the control circuit 337, the control circuit 337 causes the operation section 31 to perform a protection operation against the abnormality (protection operation step ST32).

[0137] Next, the operation of the outdoor unit 40 will be described.

[0138] The outdoor unit 40 is connected to the first electric wire 60 and the second electric wire 70. Therefore, if the first electric wire 60 and the second electric wire 70 are short-circuited at the first time tl by the above-described short-circuiting step ST22, the short-circuit detection circuit 436 of the outdoor unit 40 detects the short-circuiting of the first electric wire 60 with the second electric wire 70 at a second time t2 later than the first time tl, and outputs a prescribed electric signal to the control circuit 437 (short-circuit detection step ST41).

[0139] When the prescribed electric signal is input to the control circuit 437, the control circuit 437 causes the operation section 41 to perform a protection operation against the abnormality (protection operation step ST42).

[0140] [Comparison with the Conventional Protection Method]

[0141] Here, the conventional protection method will be described. Conventionally, in a case where an abnormality relating to a refrigerant leakage is generated and the abnormality is detected in the first indoor unit 20, a communication signal is transmitted from the first indoor unit 20 to the first electric wire 60 and the second electric wire 70 as communication lines, thereby communicating the abnormality to the second indoor unit 30 and the outdoor unit 40.

[0142] More specifically, when an abnormality such as a refrigerant leakage is detected in the first indoor unit 20, an electric signal for communicating the abnormality is input from the abnormality detection circuit 233 to the control section 221. Then, the control section 221 generates a prescribed digital signal (for example, an error code) for communicating the abnormality to other devices (for example, the second indoor unit 30 and the outdoor unit 40), and outputs the digital signal to the communication section 222. The communication section 222 converts the digital signal into a communication signal, and outputs the communication signal to the first electric wire 60 and the second electric wire 70.

[0143] In the second indoor unit 30, the communication section 322 converts the communication signal input from the first electric wire 60 and the second electric wire 70 into a digital signal, and outputs the converted digital signal to the control section 321. The control section 321 discriminates the kind of error (in this example, a refrigerant leakage) by analyzing the input digital signal, and causes the operation section 31 to perform a protection operation.

[0144] As described above, in the conventional protection method, the abnormality is communicated from the abnormality detection circuit 233 of the first indoor unit 20 to the control section 321 of the second indoor unit 30 in sequence through the control section 221, the communication section 222, the first electric wire 60 and the second electric wire 70, and the communication section 322. Therefore, in both the device that detects the abnormality (for example, the first indoor unit 20) and the device to which the abnormality is communicated (for example, the second indoor unit 30), processing (generation processing or analysis processing of a signal) in the control sections 221, 321 and conversion processing of a signal in the communication sections 222, 322 are required. The processing includes operation processing in an operation processing device such as a microprocessor, and therefore it takes time of about one minute or so until the abnormality is communicated from one device to another device.

[0145] On the other hand, in the refrigeration system 10 of the present embodiment, the first indoor unit 20 has a short-circuiting circuit 235 that short-circuits the first electric wire 60 and the second electric wire 70, which are communication lines, when the abnormality detection circuit 233 detects an abnormality. Then, when the short-circuiting is detected by the short-circuiting detection circuits 336, 436 of the second indoor unit 30 and the outdoor unit 40, the control circuits 337, 437 cause the operation units 31, 41 to perform a protection operation.

[0146] In these series of operations, the operation processing such as generation of an error code, conversion of a communication signal is not included, and the abnormality is communicated by a simpler criterion of the presence or absence of a prescribed electric signal. Therefore, the time from when the abnormality is detected by the abnormality detection circuit 233 of the first indoor unit 20 to when the operation units 31, 41 start the protection operation is, for example, within 30 seconds, and the abnormality can be communicated more quickly compared to the past.

[0147] In addition, in the refrigeration system 10, the protection substrate 23 is provided separately from the control substrate 22. By being thus configured, even in a case where an abnormality occurs in the control substrate 22, the protection operation can be performed more reliably. In addition, the control unit 221 of the control substrate 22 can be configured to be able to communicate with each unit (for example, the control circuit 237) of the protection substrate 23. In this case, since the control substrate 22 and the protection substrate 23 are provided separately, in a case where an abnormality occurs in the protection substrate 23, the control substrate 22 can detect the abnormality of the protection substrate 23 based on the inability to communicate with the protection substrate 23. In a case where the control substrate 22 detects the abnormality of the protection substrate 23, the control unit 221 causes the operation unit 21 to perform a protection operation, and communicates the abnormality to other devices (for example, the second indoor unit 30) via the communication unit 222.

[0148] Thus, by separating the control substrate 22 and the protection substrate 23, in a case where an abnormality occurs in either of the control substrate 22 and the protection substrate 23, the operation unit 21 can be caused to perform a protection operation, and the abnormality can be communicated to other devices. As a result, the reliability related to the protection operation and the abnormality communication of the refrigeration system 10 can be improved.

[0149] [Modified Example]

[0150] The present disclosure is not limited to the above-described embodiments, and various modifications can be made. In the following modified examples, the same reference numerals are assigned to the same structures as those of the above-described embodiments, and the description is appropriately omitted.

[0151] [Modified Example of the Protection Method in the Refrigeration System]

[0152] Figure 6 is a flowchart showing a modified example of the protection method in the refrigeration system 10.

[0153] In Figure 5 In this case, the first indoor unit 20 detects an abnormality. In Figure 6 In this case, the second indoor unit 30 detects an abnormality.

[0154] First, the operation of the second indoor unit 30 will be described.

[0155] For example, a case where refrigerant leaks from a portion of the refrigerant pipe 50 connected to the second indoor unit 30 (for example, a joint of the pipe) to the ceiling back space S22 and the indoor space S21 will be considered. In this case, first, the sensor 37 detects the refrigerant and outputs a detection signal to the abnormality detection circuit 333. Then, the abnormality detection circuit 333 considers that the refrigerant exceeds a prescribed concentration and a leak has occurred when the detection signal exceeds a prescribed upper limit value, and outputs a prescribed electric signal to the shorting circuit 335 and the control circuit 337 (abnormality detection step ST33).

[0156] When the prescribed electric signal is input from the abnormality detection circuit 333 to the shorting circuit 335, the switch 334 switches from the open state to the connected state. Thus, the first electric wire 60 and the second electric wire 70 are shorted (shorting step ST34).

[0157] Next, the shorting detection circuit 336 detects the shorting of the first electric wire 60 and the second electric wire 70 and outputs a prescribed electric signal to the control circuit 337 (shorting detection step ST35).

[0158] When this prescribed electric signal is input to the control circuit 337, the control circuit 337 causes the operation section 31 to perform a protection operation against the abnormality (protection operation step ST36).

[0159] Further, the control circuit 337 can also cause the operation section 31 to perform the protection operation against the abnormality when the earlier one of when the prescribed electric signal is input from the abnormality detection circuit 333 and when the prescribed electric signal is input from the shorting detection circuit 336. By so configuring, in the second indoor unit 30 in which an abnormality has occurred, the protection operation step ST36 can be performed immediately after the abnormality detection step ST33. Thus, the shorting step ST34 and the shorting detection step ST35 can be omitted, and thus the protection operation against the abnormality can be started more quickly.

[0160] Next, the operation of the first indoor unit 20 will be described.

[0161] The first indoor unit 20 is connected to the first electric wire 60 and the second electric wire 70. Therefore, if the first electric wire 60 and the second electric wire 70 are short-circuited at the first time t3 by the short-circuiting step ST34 described above, the short-circuiting detection circuit 236 of the first indoor unit 20 detects the short-circuiting of the first electric wire 60 and the second electric wire 70 at a second time t4 later than the first time t3, and outputs a prescribed electric signal to the control circuit 237 (short-circuiting detection step ST31).

[0162] When the prescribed electric signal is input to the control circuit 237, the control circuit 237 causes the operation section 21 to perform a protection operation against the abnormality (protection operation step ST25).

[0163] Next, the operation of the outdoor unit 40 will be described.

[0164] The outdoor unit 40 is connected to the first electric wire 60 and the second electric wire 70. Therefore, if the first electric wire 60 and the second electric wire 70 are short-circuited at the first time t3 by the short-circuiting step ST34 described above, the short-circuiting detection circuit 436 of the outdoor unit 40 detects the short-circuiting of the first electric wire 60 and the second electric wire 70 at a second time t4 later than the first time t3, and outputs a prescribed electric signal to the control circuit 437 (short-circuiting detection step ST43).

[0165] When the prescribed electric signal is input to the control circuit 437, the control circuit 437 causes the operation section 41 to perform a protection operation against the abnormality (protection operation step ST44).

[0166] As described above, even in the case where the second indoor unit 30 generates an abnormality, by short-circuiting the first electric wire 60 and the second electric wire 70 which are communication lines, the abnormality can be more quickly transmitted to the first indoor unit 20 and the outdoor unit 40.

[0167] [Variant of Outdoor Unit]

[0168] In the embodiment described above, the protection substrate 43 of the outdoor unit 40 has the second circuit 432 for causing the operation section 41 to perform a protection operation when short-circuiting is detected. The protection substrate 43 can also have a third circuit 431 for short-circuiting the first electric wire 60 and the second electric wire 70 when an abnormality is detected.

[0169] Figure 7 Fig. 10 is a diagram schematically showing a variant of the outdoor unit 40a. The outdoor unit 40a differs from the outdoor unit 40 of the embodiment described above in that it further has a third circuit 431 and a sensor 47. The sensor 47 is of the same structure as the sensors 27, 37, and detects, for example, the concentration of refrigerant leaking in the outdoor unit 40a. The third circuit 431 has an abnormality detection circuit 433 and a short-circuiting circuit 435.

[0170] The abnormality detection circuit 433 is of the same structure as the abnormality detection circuits 233, 333, and is electrically connected to the sensor 47. When the abnormality detection circuit 433 detects an abnormality of the outdoor unit 40a on the basis of the detection signal of the sensor 47, the abnormality detection circuit 433 outputs a prescribed electric signal to the shorting circuit 435 and the control circuit 437.

[0171] The shorting circuit 435 is of the same structure as the shorting circuits 235, 335, and includes the electric wires 67, 77 and the switch 434. The electric wires 67, 77 are connected to the first terminal 441 and the second terminal 442, respectively. When the prescribed electric signal is input from the abnormality detection circuit 433 to the shorting circuit 435, the switch 434 is switched from the open state to the connected state. Thereby, the first electric wire 60 and the second electric wire 70 are shorted.

[0172] By so configuring, it is possible to more promptly transmit the abnormality of the outdoor unit 40a to the first indoor unit 20 and the second indoor unit 30. In this case, the outdoor unit 40a can also function as the "first device" of the present disclosure.

[0173] [Variant of the refrigeration system]

[0174] Figure 8 is a diagram schematically showing the structure of the refrigeration system 10a of the variant. The refrigeration system 10a, when the first indoor unit 20 becomes an abnormal state, more promptly transmits the abnormal state to other devices (for example, the remote controllers 80) connected to the first electric wire 60 and the second electric wire 70 by shorting the first electric wire 60 and the second electric wire 70 used as communication lines.

[0175] The refrigeration system 10a has the first indoor unit 20, the second indoor unit 30, the outdoor unit 40 (in Figure 8 , the refrigerant piping 50 (in Figure 8 , the first electric wire 60, the second electric wire 70, and a plurality of remote controllers 80a, 80b, 80c. In the case where the remote controllers 80a, 80b, 80c are not particularly distinguished, they are simply referred to as "remote controllers 80". In the present variant, the first indoor unit 20 is an example of the "first device", and the remote controllers 80 are examples of the "second device".

[0176] The remote controllers 80a, 80b are wired remote controllers connected to the indoor units 20, 30 in a one-to-one relationship. Specifically, the remote controller 80a is connected to the first indoor unit 20 in a communicable manner via the external region 68 of the first electric wire 60 and the external region 78 of the second electric wire 70. In addition, the remote controller 80b is connected to the second indoor unit 30 in a communicable manner via the external region 68 of the first electric wire 60 and the external region 78 of the second electric wire 70. For example, the remote controller 80a is provided in the indoor space S11 Figure 1), and the remote controller 80b is provided in the indoor space S21 Figure 1

[0177] The remote controller 80c is a wired remote controller connected to a plurality of indoor units 20, 30 in a one-to-many relationship, and is also called a centralized management device. Specifically, the remote controller 80c is communicably connected to the first indoor unit 20 and the second indoor unit 30 via the external region 69 of the first electric wire 60 and the external region 79 of the second electric wire 70. For example, the remote controller 80c is provided in a space (a machine room or the like) different from the indoor space S11 and the indoor space S21.

[0178] Figure 9 is a diagram schematically showing the internal structure of the remote controller 80a. The remote controller 80a has a control board 82, a protection board 83, a terminal table 84, a housing 85, and a sensor 87. These structures are respectively the same as the control board 22, the protection board 23, the terminal table 24, the housing 25, and the sensor 27 of the first indoor unit 20. Regarding the structures in the remote controller 80a that are the same as those of the first indoor unit 20, appropriate description is omitted.

[0179] The remote controller 80a also has an operation section 81. The operation section 81 has a display section 811 that performs various displays to a user and an input section 812 that receives an input from the user. The display section 811 includes a display and a speaker, and performs various displays based on an instruction of a control section 821 and a control circuit 837 described later. The input section 812 receives an input for controlling the first indoor unit 20. For example, the input section 812 includes buttons for the user to set a temperature, an air volume, an air direction, and the like. The input section 812 transmits the input to the control section 821 described later when the input is received from the user.

[0180] The control board 82 is a board that controls the usual operation of the remote controller 80a, and has a control section 821 and a communication section 822. These structures are respectively the same as the control section 221 and the communication section 222. The first electric wire 60 and the second electric wire 70 are connected to the control board 82. Specifically, the first electric wire 60 (the internal region 601) is connected between a first terminal 841 and the control board 82, and the second electric wire 70 (the internal region 701) is connected between a second terminal 842 and the control board 82. The communication section 822 communicates with other devices included in the refrigeration system 10a (for example, the first indoor unit 20).

[0181] The protection board 83 has a third circuit 831 and a second circuit 832. The third circuit 831 and the second circuit 832 are composed only of hardware. The third circuit 831 is the same structure as the first circuit 231, and the second circuit 832 is the same structure as the fourth circuit 232.

[0182] ​The 3rd circuit 831 has an abnormality detection circuit 833 and a shorting circuit 835. The shorting circuit 835 has the electric wire 602, the electric wire 702, and a switch 834. These structures are the same as the abnormality detection circuit 233, the shorting circuit 235, the electric wire 63, the electric wire 73, and the switch 234, respectively.

[0183] The 2nd circuit 832 is a circuit that starts a protection operation of the remote controller 80a when the 1st electric wire 60 is shorted with the 2nd electric wire 70. The 2nd circuit 832 has a shorting detection circuit 836 and a control circuit 837. These structures are the same as the shorting detection circuit 236 and the control circuit 237, respectively.

[0184] When the shorting detection circuit 836 detects the shorting of the 1st electric wire 60 with the 2nd electric wire 70 and inputs the prescribed electric signal to the control circuit 837, the control circuit 837 controls the operation section 81 so that the operation section 81 performs a protection operation against the abnormality. The protection operation performed by the operation section 81 includes an abnormality notification operation. The abnormality notification operation of the present modification example includes causing the display section 811 to display the refrigerant leakage situation by light or sound. By these operations, it is possible to notify the user of the refrigerant leakage situation.

[0185] The terminal base 84 has a 1st terminal 841 and a 2nd terminal 842. These structures are the same as the 1st terminal 241 and the 2nd terminal 242, respectively. The external region 68 of the 1st electric wire 60 electrically connects the 1st terminal 841 with the 1st terminal 241 ( Figure 2 ) and the external region 78 of the 2nd electric wire 70 electrically connects the 2nd terminal 842 with the 2nd terminal 242 ( Figure 2 ).

[0186] The remote controller 80b is different from the remote controller 80a in that it has the input section 812 for controlling the 2nd indoor unit 30, and is the same as the remote controller 80a in other structures, and thus the description is omitted.

[0187] The remote controller 80c has the input section 812 for controlling the 1st indoor unit 20 and the 2nd indoor unit 30. In addition, the remote controller 80c does not have the 3rd circuit 831 and the sensor 87, and the shorting detection circuit 836 is electrically connected with the internal region 601 and the internal region 701. In these respects, the remote controller 80c is different from the remote controller 80a, and is the same as the remote controller 80a in other structures, and thus the description is omitted.

[0188] Next, the operation of the refrigeration system 10a is described. When the abnormality detection circuit 233 detects the abnormality of the 1st indoor unit 20 ( Figure 2When the abnormality detection circuit 833 detects an abnormality based on the detection signal of the sensor 27 of the remote controller 80a, the short circuit 235 shorts the first electric wire 60 and the second electric wire 70. As a result, the external region 68 and the external region 78 are shorted. In addition, the external region 69 and the external region 79 are also shorted. Thus, in the remote controller 80, the short detection circuit 836 detects the short, and the control circuit 837 causes the operation section 81 to perform the protection operation. For example, in order to notify the user of the abnormality related to the leakage of the refrigerant, the display section 811 causes the buzzer to sound.

[0189] As described above, in a case where the first indoor unit 20 (an example of the first device) detects an abnormality related to the leakage of the refrigerant, the remote controller 80 (an example of the second device) detects the abnormality by detecting the short of the first electric wire 60 and the second electric wire 70, and can perform the protection operation more quickly.

[0190] Further, in the present modification example, the remote controller 80 can also detect an abnormality related to the leakage of the refrigerant. Specifically, when the abnormality detection circuit 833 detects an abnormality based on the detection signal of the sensor 87 of the remote controller 80a, the short circuit 835 shorts the first electric wire 60 and the second electric wire 70. Thus, in the first indoor unit 20, the short detection circuit 236 detects the short, and the control circuit 237 causes the operation section 81 to perform the protection operation.

[0191] 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". In addition, 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 as the "first device" and the function as the "second device" of the present disclosure.

[0192] In the above-described modification example, the remote controller 80c (the centralized management device) is connected to the first indoor unit 20 and the second indoor unit 30 in a communicable manner via the first electric wire 60 and the second electric wire 70. However, the connection manner of the remote controller 80c is not limited thereto. For example, the remote controller 80c can also be connected to a plurality of outdoor units 40 (for example, the first outdoor unit 401, the second outdoor unit 402) in a communicable manner via the first electric wire 60 and the second electric wire 70. In this case, for example, when an abnormality related to the leakage of the refrigerant is detected in the first outdoor unit 401, and the first electric wire 60 and the second electric wire 70 are shorted, the remote controller 80c detects the short of the first electric wire 60 and the second electric wire 70, and causes the operation section 81 to perform the protection operation.

[0193] [Modification example of the refrigerant pipe]

[0194] In the above-described embodiment, the refrigerant pipe 50 circulates the refrigerant in both the first device (e.g., the first indoor unit 20) and the second device (e.g., the second indoor unit 30). However, the refrigerant pipe 50 does not necessarily circulate the refrigerant in both the first device and the second device, but can circulate the refrigerant in only the first device or only the second device.

[0195] For example, in the modified example of the refrigeration system 10a (see FIG. 2), the refrigerant pipe 50 is not connected to the remote controller 80. Therefore, for example, in a case where the remote controller 80 functions as the second device, the refrigerant pipe 50 can circulate the refrigerant in only the first device (e.g., the first indoor unit 20), and it is not necessary to circulate the refrigerant in both the first device and the second device. Figure 8 ). Therefore, for example, in a case where the remote controller 80 functions as the second device, the refrigerant pipe 50 can circulate the refrigerant in only the first device (e.g., the first indoor unit 20), and it is not necessary to circulate the refrigerant in both the first device and the second device.

[0196] [Modified example of the first electric wire and the second electric wire]

[0197] Figure 10 is a diagram schematically showing the first electric wire 60 and the second electric wire 70 of the modified example.

[0198] In the above-described embodiment, the first indoor unit 20 (an example of the first device), the second indoor unit 30 (an example of the second device), and the outdoor unit 40 (an example of the second device) are directly connected to each other without interposition of other devices by the first electric wire 60 and the second electric wire 70. However, the first electric wire 60 and the second electric wire 70 can electrically connect the first indoor unit 20, the second indoor unit 30, and the outdoor unit 40 to each other, and can not directly connect the first indoor unit 20, the second indoor unit 30, and the outdoor unit 40 to each other.

[0199] For example, as shown in (a) of FIG. 6, the first electric wire 60 can be divided into two lines of the first region 61a and the second region 61b, and the second electric wire 70 can be divided into two lines of the first region 71a and the second region 71b by interposing a device Dl (e.g., an amplification circuit) between the first indoor unit 20 and the second indoor unit 30. Figure 10

[0200] Further, as shown in (b) of FIG. 6, the first electric wire 60 can be divided into two lines of the first region 61a and the second region 61b, and the second electric wire 70 can be divided into two lines of the first region 71a and the second region 71b by interposing a device D2 (e.g., a filter circuit) between the first indoor unit 20 and the second indoor unit 30. Figure 10 ​As shown in (b), the first electric wire 60 and the second electric wire 70 can 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 can also be divided into three lines of 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. In addition, the second electric wire 70 can also be divided into three lines of 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.

[0201] In addition, the first electric wire 60 and the second electric wire 70 can have only two poles, and do not necessarily have to be physically divided into two lines. For example, the first electric wire 60 and the second electric wire 70 can also be aggregated into one cable.

[0202] [Modified example of protection substrate]

[0203] The protection substrate 23 of the above-described embodiment has the first circuit 231 and the fourth circuit 232. However, the protection substrate 23 can also not have the fourth circuit 232. In this case, the abnormality detection circuit 233 of the first circuit 231 can also be electrically connected to the control section 221, and output a prescribed electric signal to the control section 221 when an abnormality is detected.

[0204] [Modified example of installation site of protection substrate]

[0205] The protection substrate 23 of the above-described embodiment is housed in the housing 25. However, the protection substrate 23 can also be installed outside the housing 25. In this case, the protection substrate 23 can also be housed in a second housing (omitted from the drawing) installed in the ceiling back space S12 independently of the housing 25. In addition to the protection substrate 23, the second housing can also house, for example, the sensor 27. The same can also be applied to the protection substrates 33, 43, which can also be installed outside the housings 35, 45.

[0206] [Modified example of protection action]

[0207] The control circuit 237 can also determine the content of the protection action depending on whether or not a prescribed electric signal from the abnormality detection circuit 233 is input. For example, in a case where prescribed electric signals are input to the control circuit 237 from both the short-circuit detection circuit 236 and the abnormality detection circuit 233, the first indoor unit 20 itself generates an abnormality. Therefore, as the protection action, the control circuit 237 performs both an abnormality suppression action (for example, rotation of the fan 211 based on the maximum rotation speed) and an abnormality notification action (for example, flickering of the LED in the display section 213).

[0208] On the other hand, for example, in a case where although the prescribed electric signal is input from the short-circuit detection circuit 236 to the control circuit 237, the prescribed electric signal is not input from the abnormality detection circuit 233 to the control circuit 237, the second indoor unit 30 generates an abnormality, and the first indoor unit 20 itself does not generate an abnormality. As in the above-described embodiment, in a case where the first indoor unit 20 and the second indoor unit 30 are respectively provided in different rooms, even in a case where a leakage of the refrigerant has occurred in the second indoor unit 30, necessity of performing the abnormality suppression action in the first indoor unit 20 is low. In addition, if the abnormality suppression action such as the rotation of the fan 211 at the maximum rotation speed is performed in the first indoor unit 20, it is possible to cause the user to feel uncomfortable.

[0209] Therefore, in a case where although the prescribed electric signal is input from the short-circuit detection circuit 236 to the control circuit 237, the prescribed electric signal is not input from the abnormality detection circuit 233 to the control circuit 237, the control circuit 237 can cause only the operation portion 21 to perform the abnormality notification action, and not perform the abnormality suppression action.

[0210] By thus configuring, in the device (for example, the second indoor unit 30) in which the abnormality has occurred in the refrigeration system 10, both the abnormality suppression action and the abnormality notification action are performed as the protection action, and in the device (for example, the first indoor unit 20) in which the abnormality has not occurred, only the abnormality notification action can be performed as the protection action. Thereby, it is possible to suppress causing the user who uses the first indoor unit 20 to feel uncomfortable, and it is possible to more quickly notify the user of the abnormality of the refrigeration system 10. In addition, the outdoor unit 40 can perform the abnormality suppression action even in a case where the outdoor unit 40 itself does not generate an abnormality.

[0211] [Other Modification Examples]

[0212] In the above-described embodiments, the refrigerant pipe 50 directly connects the first indoor unit 20 and the second indoor unit 30. However, the refrigerant pipe 50 only needs to have a function of circulating refrigerant in the first indoor unit 20 and the second indoor unit 30, and the first indoor unit 20 and the second indoor unit 30 can not be directly connected by the refrigerant pipe 50. For example, a branching unit for branching the refrigerant pipe 50 for other indoor units (or an outdoor unit) can be inserted between the first indoor unit 20 and the second indoor unit 30, and the refrigerant pipe 50 and the first indoor unit 20 and the second indoor unit 30 can be connected via the other indoor units. In this case, the refrigerant pipe 50 is not provided between the first indoor unit 20 and the second indoor unit 30, but can circulate refrigerant in the first indoor unit 20 and the second indoor unit 30 via the other indoor units. Similarly, the refrigerant pipe 50 only needs to have a function of circulating refrigerant in the first indoor unit 20 and the outdoor unit 40, and the first indoor unit 20 and the outdoor unit 40 can not be directly connected by the refrigerant pipe 50.

[0213] Further, as for each of the above-described embodiments, at least a part thereof can be arbitrarily combined with each other.

[0214] [Effects of Embodiments]

[0215] (1) The refrigeration system 10, 10a of the above-described embodiments and modified examples includes: a first device 20, 80; a second device 20, 30, 40, 80 that is communicably connected to the first device 20, 80 via a first electric wire 60 and a second electric wire 70; and a refrigerant pipe 50 that circulates refrigerant in the first device 20, 80 or the second device 20, 30, 40, 80, the first device 20, 80 has a first circuit 231, 831 that shorts the first electric wire 60 and the second electric wire 70 when detecting an abnormality related to a refrigerant leakage, and the second device 20, 30, 40, 80 has a second circuit 232, 332, 432, 832 that starts a protection action against the abnormality when the first electric wire 60 and the second electric wire 70 are shorted.

[0216] According to the refrigeration system 10, 10a, by shorting the first electric wire 60 and the second electric wire 70 used in communication between the first device 20, 80 and the second device 20, 30, 40, 80, it is possible to more quickly transfer an abnormality detected by the first device 20, 80 to the second device 20, 30, 40, 80 side. Thereby, it is possible to advance the start of a protection action against the abnormality.

[0217] (2) In the refrigeration system 10, 10a of the above embodiment and modification, the first circuit 231, 831 includes an abnormality detection circuit 233, 833 that detects an abnormality related to a refrigerant leakage, and a shorting circuit 235, 835 that includes a switch 234, 834 connected in parallel to the first electric wire 60 and the second electric wire 70, and switches the switch 234, 834 from an open state to a connected state when an abnormality related to a refrigerant leakage is detected by the abnormality detection circuit 233, 833.

[0218] (3) In the refrigeration system 10, 10a of the above embodiment and modification, the abnormality detection circuit 233, 833 detects an abnormality based on a detection signal of a sensor 27, 87 that detects a refrigerant leakage.

[0219] (4) In the refrigeration system 10, 10a of the above embodiment and modification, the second circuit 232, 332, 432, 832 has a shorting detection circuit 236, 336, 436, 836 that detects a shorting of the first electric wire 60 and the second electric wire 70, and a control circuit 237, 337, 437, 837 that is electrically connected to the operation section 21, 31, 41, 81 that performs a protection operation against an abnormality, and controls the operation section 21, 31, 41, 81 when a shorting of the first electric wire 60 and the second electric wire 70 is detected by the shorting detection circuit 236, 336, 436, 836, and the second circuit 232, 332, 432, 832 is configured only by hardware.

[0220] According to the refrigeration system 10, 10a, the protection operation of the second device 20, 30, 40, 80 is started by the second circuit 232, 332, 432, 832 configured only by hardware, and it is possible to avoid, for example, an error due to software. Thus, it is possible to more reliably start the protection operation.

[0221] (5) In the refrigeration system 10 of the above embodiment, the first device 20 is a first indoor unit 20, and the second device 30, 40 is a second indoor unit 30 or an outdoor unit 40.

[0222] (6) In the refrigeration system 10a of the above modification, the first device 20, 80 is one of the first indoor unit 20 or the 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.

[0223] (7) In the refrigeration system 10, 10a of the above-described embodiment and modification example, the second device 20, 30, 40, 80 further has a third circuit 231, 331, 431, 831 that shorts the first electric wire 60 and the second electric wire 70 when detecting an abnormality related to a refrigerant leakage, and the first device 20, 80 further has a fourth circuit 232, 832 that starts a protection action of the first device 20, 80 when the first electric wire 60 and the second electric wire 70 are shorted.

[0224] By shorting the first electric wire 60 and the second electric wire 70 used in the communication between the first device 20, 80 and the second device 20, 30, 40, 80, it is possible to more quickly transfer an abnormality of the second device 20, 30, 40, 80 to the first device 20, 80 side. Thereby, it is possible to advance the start of the protection action of the first device 20, 80.

[0225] (8) In the refrigeration system 10, 10a of the above-described embodiment and modification example, the first device 20, 80 has a protection substrate 23, 83 that includes the first circuit 231, 831 and the fourth circuit 232, 832, and a control substrate 22, 82 that is provided separately from the protection substrate 23, 83 and controls an action of the first device 20, 80.

[0226] By providing the protection substrate 23, 83 separately from the control substrate 22, 82, it is possible to more reliably perform a protection action even in a case where an abnormality has occurred in the control substrate 22, 82.

[0227] (9) In the refrigeration system 10, 10a of the above-described embodiment and modification example, the first device 20, 80 has a protection substrate 23, 83 that includes the first circuit 231, 831, and a control substrate 22, 82 that is provided separately from the protection substrate 23, 83 and controls an action of the first device 20, 80.

[0228] By providing the protection substrate 23, 83 separately from the control substrate 22, 82, it is possible to more reliably perform a protection action even in a case where an abnormality has occurred in the control substrate 22, 82.

[0229] The above-described embodiment has been described, but it should be understood that various changes in form and details can be made without departing from the spirit and scope of the claims.

[0230] Explanation of Reference Signs

[0231] 10: refrigeration system; 10a: refrigeration system; 20: 1st indoor unit (example of 1st device or 2nd device); 21: operation part; 211: fan; 212: heat exchanger; 213: display part; 22: control substrate; 221: control part; 222: communication part; 23: protection substrate; 231: 1st circuit; 232: 4th circuit; 233: abnormality detection circuit; 234: switch; 235: short circuit; 236: short circuit detection circuit; 237: control circuit; 24: terminal table; 241: 1st terminal; 242: 2nd terminal; 25: housing; 26: remote controller; 261: display part; 262: input part; 27: sensor; 30: 2nd indoor unit (example of 2nd device); 31: operation part; 311: fan; 312: heat exchanger; 313: display part; 32: control substrate; 321: control part; 322: communication part; 33: protection substrate; 331: 3rd circuit; 332: 2nd circuit; 333: abnormality detection circuit; 334: switch; 335: short circuit; 336: short circuit detection circuit; 337: control circuit; 34: terminal table; 341: 1st terminal; 342: 2nd terminal; 35: housing; 36: remote controller; 361: display part; 362: input part; 37: sensor; 40: outdoor unit (example of 2nd device); 40a: outdoor unit (example of 1st device or 2nd device); 41: operation part; 411: fan; 412: heat exchanger; 413: compressor; 42: control substrate; 421: control part; 422: communication part; 43: protection substrate; 431: 3rd circuit; 432: 2nd circuit; 433: abnormality detection circuit; 434: switch; 435: short circuit; 436: short circuit detection circuit; 437: control circuit; 44: terminal table; 441: 1st terminal; 442: 2nd terminal; 45: housing; 47: sensor; 50: refrigerant pipe; 60: 1st electric wire; 61a: 1st region; 61b: 2nd region; 61c: 1st region; 61d: 2nd region; 61e: 3rd region; 61: outer region; 62, 64, 66: inner region; 63: electric wire; 65: electric wire; 67: electric wire; 68: outer region; 69: outer region; 601: inner region; 602: electric wire; 70: 2nd electric wire; 71a: 1st region; 71b: 2nd region; 71c: 1st region; 71d: 2nd region; 71e: 3rd region; 71: outer region; 72, 74, 76: inner region; 73: electric wire; 75: electric wire; 77: electric wire; 78: outer region; 79: outer region; 701: inner region; 702: electric wire; 80a, 80b, 80c: remote controller; 80: remote controller; 81: operation part; 811: display part; 812: input part; 82: control substrate; 821: control part; 822: communication part; 83: protection substrate; 831: 3rd circuit; 832: 2nd 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 back space; S21: indoor space; S22: ceiling back space; S31: outdoor space; t1: first time; t2: second time; t3: first time; t4: second time; D1: device; D2: device.

Claims

1. A refrigeration system comprising: a first device; a second device communicatively connected to the first device via a first electric line (60) and a second electric line (70); and a refrigerant pipe (50) circulating refrigerant in the first device or the second device, the first device having a first circuit that shorts the first electric line (60) and the second electric line (70) when detecting an abnormality related to a refrigerant leakage, the second device having a second circuit that starts a protection action against the abnormality when the first electric line (60) and the second electric line (70) are shorted.

2. The refrigeration system according to claim 1, wherein the first circuit has: an abnormality detection circuit (233, 833) that detects the abnormality related to the refrigerant leakage; and a shorting circuit (235, 835) including a switch (234, 834) connected in parallel to the first electric line (60) and the second electric line (70), the switch (234, 834) being switched from an open state to a connected state when the abnormality related to the refrigerant leakage is detected by the abnormality detection circuit (233, 833).

3. The refrigeration system according to claim 2, wherein the abnormality detection circuit (233, 833) detects the abnormality related to the refrigerant leakage based on a detection signal of a sensor (27, 87) that detects the refrigerant leakage.

4. The refrigeration system according to any one of claims 1 to 3, wherein the second circuit has: a shorting detection circuit (236, 336, 436, 836) that detects the shorting of the first electric line (60) and the second electric line (70); and a control circuit (237, 337, 437, 837) electrically connected to an action section (21, 31, 41, 81) that performs the protection action against the abnormality, the control circuit (237, 337, 437, 837) controlling the action section (21, 31, 41, 81) when the shorting of the first electric line (60) and the second electric line (70) is detected by the shorting detection circuit (236, 336, 436, 836), the second circuit being composed of only hardware.

5. The refrigeration system according to any one of claims 1 to 3, wherein the first device is a first indoor unit (20), the second device is a second indoor unit (30) or an outdoor unit (40).

6. The refrigeration system according to any one of claims 1 to 3, wherein the first device is one of a first indoor unit (20) and a remote controller (80) having an input section (812) for controlling the first indoor unit (20), the second device is the other of the first indoor unit (20) and the remote controller (80).

7. The refrigeration system according to any one of claims 1 to 3, wherein the second device further has a third circuit that shorts the first electric line (60) and the second electric line (70) when detecting the abnormality related to the refrigerant leakage. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The first device further has a fourth circuit which starts the protection operation of the first device when the first electric wire (60) is short-circuited to the second electric wire (70).

8. The refrigeration system according to claim 7, wherein The first device has: a protection substrate (23, 83) which contains the first circuit and the fourth circuit; and a control substrate (22, 82) which is provided separately from the protection substrate (23, 83) and controls the operation of the first device.

9. The refrigeration system according to any one of claims 1 to 3, wherein The first device has: a protection substrate (23, 83) which contains the first circuit; and a control substrate (22, 82) which is provided separately from the protection substrate (23, 83) and controls the operation of the first device.

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