Patent Description:
An air conditioning apparatus may be provided with various safety devices as a measure against refrigerant leakage. For example, <CIT> discloses an air conditioning system including a refrigerant detector, an alarm device, and an isolation valve as safety devices.

<CIT> discloses a control system of an air conditioner, which includes a setting unit configured to switch between enabling and disabling of a safety function of the air conditioner on the basis of a total amount of refrigerant of the air conditioner, wherein the control system enables the safety function when the total amount of refrigerant of the air conditioner is large and disables the safety function when the total amount of refrigerant of the air conditioner is small.

The japanese standard JRA 4086T entitled "Requirements of refrigerant leak detector and alarm for air conditioning and refrigeration equipment" describes to a startup interlock function which prevents operation when safety measures are not in place; wherein contact points for short-circuiting the interlock function are foreseen.

Such an air conditioning system is required to have high reliability to ensure that the safety devices operate reliably when a refrigerant leaks during the operation of the air conditioning apparatus. Therefore, it is considered to use interlock in the air conditioning apparatus to prohibit the operation of the air conditioning apparatus when the safety devices are not operable.

However, meanwhile, depending on the amount of refrigerant charged in the air conditioning apparatus or the like, the safety devices may not be required. However, since the air conditioning apparatus may be used together with a plurality of safety devices, in the air conditioning apparatus that uses interlock, if the interlock for each safety device is released when the safety device is not used, there is a problem that the amount of work during installation increases.

An air conditioning apparatus of a first aspect is defined in claim <NUM>. The air conditioning apparatus including a refrigerant circuit, and includes a connecting portion, a circuit configuration portion, a first member, and a control unit. To the connecting portion, a first electric wire connected to a first device of a plurality of safety devices and a second electric wire connected to a second device of the plurality of safety devices are connected. The plurality of safety devices includes at least two types of a refrigerant detector, an alarm device, an isolation valve, and a ventilation device. The second device is different from the first device in type. The circuit configuration portion forms an interlock circuit together with the first electric wire and the second electric wire connected to the connecting portion. The first member can form a first circuit including at least part of the circuit configuration portion without going through the first electric wire and the second electric wire. The control unit prohibits an operation of the air conditioning apparatus when no current flows through either the interlock circuit or the first circuit.

Note that the case where no current flows through the interlock circuit includes the case where part of the interlock circuit is broken and the case where part of the interlock circuit is disconnected from the electric wire, in addition to the case where the interlock circuit does not exist. The case where no current flows through the first circuit includes the case where the first circuit is not formed.

In the air conditioning apparatus of the first aspect, since the first member can be used to form the first circuit that can release the interlock of the air conditioning apparatus, it is not necessary to release the interlock for each of the plurality of safety devices when the safety devices are not used, providing good workability.

The first circuit is a circuit formed by short-circuiting a first portion of the circuit configuration portion and a second portion of the circuit configuration portion.

The connecting portion includes a first electric wire connecting portion and a second electric wire connecting portion, the first electric wire is connected to the first device and to the first electric wire connecting portion, and the second electric wire connected to the second device and to the second electric wire connecting portion.

The circuit configuration portion includes: a first portion that electrically connects the first electric wire connecting portion to the control unit, a second portion that electrically connects the second electric wire connecting portion to the control unit, and a coupling portion that electrically connects the first electric wire connecting portion to the second electric wire connecting portion.

The air conditioning apparatus of the first aspect can easily release the interlock with a plurality of safety devices at the same time by short-circuiting the circuit configuration portion.

The air conditioning apparatus of the second aspect is the air conditioning apparatus of the first aspect, further including a mounting portion to which the first member is attachable and detachable. The first circuit is formed by removing the first member from the mounting portion.

In the air conditioning apparatus of the second aspect, the first circuit can be formed by removing the first member, and the interlock with a plurality of safety devices can be quickly released. Since the first member is normally attached to the mounting portion when the air conditioning apparatus is installed, the possibility of loss of the first member can be reduced.

The air conditioning apparatus of the third aspect is the air conditioning apparatus of the first aspect, further including a mounting portion to which the first member is attachable and detachable. The first circuit is formed by attaching the first member to the mounting portion.

In the air conditioning apparatus of the third aspect, the first circuit can be formed by attaching the first member, and the interlock with a plurality of safety devices can be quickly released.

<FIG> is a schematic electrical circuit diagram for describing the interlock circuit and the first circuit of the air conditioning apparatus of a modification D not according to the invention.

One embodiment of an air conditioning apparatus of the present disclosure will be described.

With reference to <FIG> and <FIG>, an air conditioning system <NUM> including an air conditioning apparatus <NUM> according to one embodiment and a plurality of types of safety devices will be described. <FIG> is a block diagram of the air conditioning system <NUM>. In <FIG>, depiction of devices constituting a refrigerant circuit <NUM> excluding a compressor <NUM> of a heat source unit <NUM> of the air conditioning apparatus <NUM>, a first fan <NUM>, and a second fan <NUM> is omitted. <FIG> is a schematic configuration diagram of the air conditioning system <NUM>.

The air conditioning apparatus <NUM> is an apparatus to cool or heat air conditioning target space by using a vapor compression refrigeration cycle. The air conditioning apparatus <NUM> includes a utilization unit <NUM> and the heat source unit <NUM> (see <FIG>).

In the present embodiment, the plurality of types of safety devices included in the air conditioning system <NUM> includes four types of safety devices: refrigerant detector <NUM>, alarm device <NUM>, ventilation device <NUM>, and isolation valve <NUM> (see <FIG>).

Note that in the following, when describing the interlock function of the air conditioning apparatus <NUM>, in order to avoid complicated description, the case where the air conditioning system <NUM> includes two types of safety devices (first device <NUM> and second device <NUM>) will be described. The following embodiment will mainly describe, as an example, the case where the first device <NUM> is the refrigerant detector <NUM> and the second device <NUM> is the alarm device <NUM>. Note that for example, the first device <NUM> and the second device <NUM> may be another combination of the plurality of types of safety devices.

The air conditioning apparatus <NUM> is an apparatus to cool and heat the air conditioning target space by using the vapor compression refrigeration cycle. Examples of the air conditioning target space include a space in a building such as an office building, a commercial facility, or a residence. Note that the air conditioning apparatus <NUM> may not be an apparatus to be used for both cooling and heating uses of the air conditioning target space, but may be, for example, an apparatus to be used for only one of cooling and heating uses.

The air conditioning apparatus <NUM> is configured to electrically connect various safety devices in order to ensure safety when a refrigerant leaks. The air conditioning apparatus <NUM> has an interlock function. The interlock function here is a function of prohibiting activation and operation of the air conditioning apparatus <NUM> when the safety devices required for the air conditioning system <NUM> are not supplied with power and are not operational.

However, the air conditioning apparatus <NUM> is configured to be operational even when the safety devices are not connected, by forming a first circuit <NUM> using the first member <NUM> described later.

The air conditioning apparatus <NUM> mainly includes the heat source unit <NUM>, the utilization unit <NUM>, a refrigerant connection pipe, and a remote controller <NUM>, as shown in <FIG> and <FIG>. In addition, the air conditioning apparatus <NUM> includes a connecting portion <NUM>, a circuit configuration portion <NUM>, and the first member <NUM> related to the interlock function and release thereof.

The heat source unit <NUM> includes a heat source unit control device <NUM>. The utilization unit <NUM> includes a utilization unit control device <NUM>. The remote controller <NUM> includes a remote controller control device 48a. The heat source unit control device <NUM>, the utilization unit control device <NUM>, and the remote controller control device 48a cooperate to function as the control unit <NUM> described later.

The refrigerant connection pipe includes a liquid refrigerant connection pipe <NUM> and a gas refrigerant connection pipe <NUM>. The liquid refrigerant connection pipe <NUM> and the gas refrigerant connection pipe <NUM> are refrigerant connection pipes to connect the heat source unit <NUM> to the utilization unit <NUM>. In the air conditioning apparatus <NUM>, the heat source unit <NUM> and the utilization unit <NUM> are connected via the refrigerant connection pipes <NUM> and <NUM> to constitute the refrigerant circuit <NUM>.

The refrigerant enclosed in the refrigerant circuit <NUM> is, but is not limited to, a flammable refrigerant. The flammable refrigerant includes the refrigerant categorized as Class <NUM> (higher flammability), Class <NUM> (lower flammability), and Subclass <NUM> (slight flammability) in the standards according to ASHRAE <NUM>, Designation and Safety Classification of Refrigerants in the Unites States or the standards according to ISO <NUM>, Refrigerants - Designation and Safety Classification.

An example of the adopted refrigerant is any one of R1234yf, R1234ze(E), R516A, R445A, R444A, R454C, R444B, R454A, R455A, R457A, R459B, R452B, R454B, R447B, R32, R447A, R446A, and R459A.

In the present embodiment, the refrigerant used is R32. Note that the present disclosure is also useful for a case where the refrigerant is not flammable.

The air conditioning apparatus <NUM> includes one heat source unit <NUM> as shown in <FIG>. In addition, the air conditioning apparatus <NUM> includes one utilization unit <NUM> as shown in <FIG>. However, the air conditioning apparatus <NUM> may include a plurality of utilization units <NUM> connected in parallel to the heat source unit <NUM>. The air conditioning apparatus <NUM> may include a plurality of heat source units <NUM>.

The heat source unit <NUM>, the utilization unit <NUM>, the refrigerant connection pipes <NUM> and <NUM>, and the control unit <NUM> will be described in detail below. The circuit configuration portion <NUM>, the connecting portion <NUM>, a mounting portion <NUM>, and the first member <NUM> related to the interlock function of the air conditioning apparatus <NUM> and release of the interlock function will be described in detail below.

One example of the configuration of the heat source unit <NUM> will be described with reference to <FIG>.

The heat source unit <NUM> is installed outside the air conditioning target space, for example, on the roof of a building, near a wall surface of a building, or the like.

The heat source unit <NUM> mainly includes an accumulator <NUM>, the compressor <NUM>, a flow direction switching mechanism <NUM>, a heat source heat exchanger <NUM>, a first expansion mechanism <NUM>, a first shutoff valve <NUM>, a second shutoff valve <NUM>, and the first fan <NUM> (see <FIG>). Note that the heat source unit <NUM> may not include some of the devices described here. For example, in a case where the air conditioning apparatus <NUM> only cools the air conditioning target space, the heat source unit <NUM> may not include the flow direction switching mechanism <NUM>. The heat source unit <NUM> may include, as necessary, a device not described here.

The heat source unit <NUM> mainly includes, as refrigerant pipes connecting various devices constituting the refrigerant circuit <NUM>, a suction pipe <NUM>, a discharge pipe <NUM>, a first gas refrigerant pipe <NUM>, a liquid refrigerant pipe <NUM>, and a second gas refrigerant pipe <NUM> (see <FIG>). The suction pipe <NUM> connects the flow direction switching mechanism <NUM> to a suction side of the compressor <NUM>. The suction pipe <NUM> is provided with the accumulator <NUM>. The discharge pipe <NUM> connects a discharge side of the compressor <NUM> to the flow direction switching mechanism <NUM>. The first gas refrigerant pipe <NUM> connects the flow direction switching mechanism <NUM> to a gas side of the heat source heat exchanger <NUM>. The liquid refrigerant pipe <NUM> connects a liquid side of the heat source heat exchanger <NUM> to the first shutoff valve <NUM>. The liquid refrigerant pipe <NUM> is provided with the first expansion mechanism <NUM>. The second gas refrigerant pipe <NUM> connects the flow direction switching mechanism <NUM> to the second shutoff valve <NUM>.

The compressor <NUM> is a device to suck a low-pressure refrigerant in the refrigeration cycle from the suction pipe <NUM>, compress the refrigerant by means of a compression mechanism (not shown), and discharge the compressed refrigerant to the discharge pipe <NUM>.

The flow direction switching mechanism <NUM> switches a refrigerant flow direction to change a state of the refrigerant circuit <NUM> between a first state and a second state. In the present embodiment, the flow direction switching mechanism <NUM> is a four-way switching valve, but is not limited to this example and may include a plurality of valves and pipes. When the refrigerant circuit <NUM> is in the first state, the heat source heat exchanger <NUM> functions as a refrigerant radiator (condenser) and a utilization heat exchanger <NUM> functions as a refrigerant evaporator. When the refrigerant circuit <NUM> is in the second state, the heat source heat exchanger <NUM> functions as a refrigerant evaporator and the utilization heat exchanger <NUM> functions as a refrigerant radiator. When the flow direction switching mechanism <NUM> brings the refrigerant circuit <NUM> into the first state, the flow direction switching mechanism <NUM> causes the suction pipe <NUM> to communicate with the second gas refrigerant pipe <NUM> and causes the discharge pipe <NUM> to communicate with the first gas refrigerant pipe <NUM> (see solid lines in the flow direction switching mechanism <NUM> in <FIG>). When the flow direction switching mechanism <NUM> brings the refrigerant circuit <NUM> into the second state, the flow direction switching mechanism <NUM> causes the suction pipe <NUM> to communicate with the first gas refrigerant pipe <NUM> and causes the discharge pipe <NUM> to communicate with the second gas refrigerant pipe <NUM> (see broken lines in the flow direction switching mechanism <NUM> in <FIG>).

The heat source heat exchanger <NUM> is a device to cause heat exchange between a refrigerant flowing inside and air at an installation site of the heat source unit <NUM> (heat source air). The heat source heat exchanger <NUM> is, but is not limited to any type, for example, a fin- and-tube heat exchanger including a plurality of heat transfer tubes and fins (not shown). The heat source heat exchanger <NUM> has a first end connected to the first gas refrigerant pipe <NUM>. The heat source heat exchanger <NUM> has a second end connected to the liquid refrigerant pipe <NUM>.

The first expansion mechanism <NUM> is disposed between the heat source heat exchanger <NUM> and the utilization heat exchanger <NUM> in the refrigerant circuit <NUM>. The first expansion mechanism <NUM> is disposed in the liquid refrigerant pipe <NUM> between the heat source heat exchanger <NUM> and the first shutoff valve <NUM>. The first expansion mechanism <NUM> adjusts pressure and a flow rate of the refrigerant flowing through the liquid refrigerant pipe <NUM>. In the present embodiment, the first expansion mechanism <NUM> is an electronic expansion valve having a variable opening degree. However, for example, the first expansion mechanism <NUM> may be a temperature sensitive cylinder expansion valve, a capillary tube, or the like.

The accumulator <NUM> is a container having a gas-liquid separation function of separating an influent refrigerant into a gas refrigerant and a liquid refrigerant. The accumulator <NUM> is also a container having a function of storing an excess refrigerant generated in response to fluctuations in the operating load and the like.

The first shutoff valve <NUM> is a valve provided at a connecting portion between the liquid refrigerant pipe <NUM> and the liquid refrigerant connection pipe <NUM>. The second shutoff valve <NUM> is a valve provided at a connecting portion between the second gas refrigerant pipe <NUM> and the gas refrigerant connection pipe <NUM>. The first shutoff valve <NUM> and the second shutoff valve <NUM> are opened while the air conditioning apparatus <NUM> is in operation.

The first fan <NUM> is a fan to suck heat source air outside the heat source unit <NUM> into a casing (not shown) of the heat source unit <NUM>, supply the heat source heat exchanger <NUM> with the heat source air, and discharge air subjected to heat exchange with the refrigerant in the heat source heat exchanger <NUM> out of the casing of the heat source unit <NUM>. The first fan <NUM> is, for example, a propeller fan. However, the type of the first fan <NUM> is not limited to the propeller fan and may be appropriately selected.

One example of the configuration of the utilization unit <NUM> will be described with reference to <FIG>.

The utilization unit <NUM> is, for example, a unit installed in the air conditioning target space. The utilization unit <NUM> is, for example, a ceiling embedded type unit, but alternatively may be a ceiling pendant type, a wall mounted type, or a floor-standing type unit. The utilization unit <NUM> may be disposed outside the air conditioning target space. For example, the utilization unit <NUM> may be installed in an attic space, a machine chamber, or the like. In this case, there is disposed an air passage to supply air subjected to heat exchange with a refrigerant in the utilization heat exchanger <NUM> from the utilization unit <NUM> to the air conditioning target space. Examples of the air passage include a duct. However, the type of air passage is not limited to a duct, and may be appropriately selected.

The utilization unit <NUM> mainly includes a second expansion mechanism <NUM>, the utilization heat exchanger <NUM>, and the second fan <NUM> (see <FIG>).

The second expansion mechanism <NUM> is disposed between the heat source heat exchanger <NUM> and the utilization heat exchanger <NUM> in the refrigerant circuit <NUM>. The second expansion mechanism <NUM> is disposed in a refrigerant pipe connecting the utilization heat exchanger <NUM> to the liquid refrigerant connection pipe <NUM>. The second expansion mechanism <NUM> adjusts pressure and a flow rate of the refrigerant flowing through the refrigerant pipe. In the present embodiment, the second expansion mechanism <NUM> is, but is not limited to, an electronic expansion valve having a variable opening degree.

The utilization heat exchanger <NUM> causes heat exchange between the refrigerant flowing through the utilization heat exchanger <NUM> and air in the air conditioning target space. The utilization heat exchanger <NUM> is, but is not limited to any type, for example, a fin-and- tube heat exchanger including a plurality of heat transfer tubes and fins (not shown). The utilization heat exchanger <NUM> has a first end connected to the liquid refrigerant connection pipe <NUM> via the refrigerant pipe. The utilization heat exchanger <NUM> has a second end connected to the gas refrigerant connection pipe <NUM> via the refrigerant pipe.

The second fan <NUM> is a mechanism to suck air in the air conditioning target space into a casing (not shown) of the utilization unit <NUM>, supply the air to the utilization heat exchanger <NUM>, and blow out the air subjected to heat exchange with the refrigerant in the utilization heat exchanger <NUM> to the air conditioning target space. Examples of the second fan <NUM> include a turbo fan. However, the type of the second fan <NUM> is not limited to a turbo fan, and may be appropriately selected.

The liquid refrigerant connection pipe <NUM> and the gas refrigerant connection pipe <NUM> are refrigerant connection pipes to connect the heat source unit <NUM> to the utilization unit <NUM>. The liquid refrigerant connection pipe <NUM> is provided with a first isolation valve <NUM> of the isolation valve <NUM>. The gas refrigerant connection pipe <NUM> is provided with a second isolation valve <NUM> of the isolation valve <NUM>.

The first isolation valve <NUM> and the second isolation valve <NUM> are, but are not limited to, electromagnetic valves or motor operated valves, for example. The first isolation valve <NUM>, when closed, can prevent the refrigerant from flowing in from the heat source unit <NUM> side of the first isolation valve <NUM> into the utilization unit <NUM> through the liquid refrigerant connection pipe <NUM>. The second isolation valve <NUM>, when closed, can prevent the refrigerant from flowing in from the heat source unit <NUM> side of the second isolation valve <NUM> into the utilization unit <NUM> through the gas refrigerant connection pipe <NUM>.

The control unit <NUM> includes the heat source unit control device <NUM>, the utilization unit control device <NUM>, and the remote controller control device 48a. In other words, the heat source unit control device <NUM>, the utilization unit control device <NUM>, and the remote controller control device 48a cooperate to function as the control unit <NUM>. Note that the control unit <NUM> is required at least to function as described below as a whole. Therefore, the operation described below as being performed by any of the heat source unit control device <NUM>, the utilization unit control device <NUM>, and the remote controller control device 48a may be performed by the other control device <NUM>, <NUM>, or 48a within a consistent range. Part of the function of the control unit <NUM> described below may be performed by another control device provided separately from the heat source unit control device <NUM>, the utilization unit control device <NUM>, and the remote controller control device 48a.

The control unit <NUM> is configured by connecting the heat source unit control device <NUM>, the utilization unit control device <NUM>, and the remote controller control device 48a via a communication line <NUM> (see <FIG>).

To control operations of various devices of the air conditioning apparatus <NUM>, the control unit <NUM> mainly includes a microcontroller unit (MCU), and various electric circuits and electronic circuits. The MCU includes a CPU, memory, I/O interface, and the like. Various programs to be executed by the CPU of the MCU are stored in the memory of the MCU. Note that various functions of the control unit <NUM> described below may be implemented by hardware, software, or hardware and software cooperating with each other. The control unit <NUM> controls the operations of various devices of the air conditioning apparatus <NUM> based on instructions input to the remote controller <NUM>, measured values of various sensors provided in the heat source unit <NUM> and the utilization unit <NUM>, and the like.

For example, during a cooling operation, the control unit <NUM> controls the operation of the flow direction switching mechanism <NUM> to switch the state of the refrigerant circuit <NUM> to the first state in which the heat source heat exchanger <NUM> functions as a refrigerant radiator and the utilization heat exchanger <NUM> functions as a refrigerant evaporator. During the cooling operation, the control unit <NUM> operates the compressor <NUM>, the first fan <NUM>, and the second fan <NUM>. During the cooling operation, the control unit <NUM> adjusts the number of revolutions of motors of the compressor <NUM>, the first fan <NUM>, and the second fan <NUM>, and the opening degree of the electronic expansion valve, which is an example of the first expansion mechanism <NUM> and the second expansion mechanism <NUM>, to a predetermined opening degree, based on the measured values of various sensors, set temperature, and the like. Meanwhile, during a heating operation, the control unit <NUM> controls the operation of the flow direction switching mechanism <NUM> to switch the state of the refrigerant circuit <NUM> to the second state in which the heat source heat exchanger <NUM> functions as a refrigerant evaporator and the utilization heat exchanger <NUM> functions as a refrigerant radiator. During the heating operation, the control unit <NUM> operates the compressor <NUM>, the first fan <NUM>, and the second fan <NUM>. During the heating operation, the control unit <NUM> adjusts the number of revolutions of motors of the compressor <NUM>, the first fan <NUM>, and the second fan <NUM>, and the opening degree of the electronic expansion valve, which is an example of the first expansion mechanism <NUM> and the second expansion mechanism <NUM>, to a predetermined opening degree, based on the measured values of various sensors, set temperature, and the like.

Specific control of the operations of various devices of the air conditioning apparatus <NUM> during the cooling operation and the heating operation has various control modes that are publicly known. Therefore, description will be omitted here to avoid complicated description.

The control unit <NUM> determines refrigerant leakage based on a detection signal output from the refrigerant detector <NUM>. On determination that the refrigerant is leaking, the control unit <NUM> transmits a signal for executing an operation when the refrigerant leakage is detected to the alarm device <NUM>, the ventilation device <NUM>, and the isolation valve <NUM> serving as safety devices. On determination that the refrigerant is leaking, the control unit <NUM> prohibits or stops the operation of the air conditioning apparatus <NUM>.

The heat source unit control device <NUM>, the utilization unit control device <NUM>, and the remote controller <NUM> including the remote controller control device 48a will be described in detail below.

The heat source unit control device <NUM> mainly includes a microcontroller unit (MCU), and various electric circuits and electronic circuits to control various devices of the heat source unit <NUM>. The MCU includes a CPU, memory, I/O interface, and the like. Various programs to be executed by the CPU of the MCU are stored in the memory of the MCU. Note that various functions of the heat source unit control device <NUM> described below may be implemented by hardware, software, or hardware and software cooperating with each other.

The heat source unit control device <NUM> is electrically connected to various devices of the heat source unit <NUM>, including the compressor <NUM>, the flow direction switching mechanism <NUM>, the first expansion mechanism <NUM>, and the first fan <NUM> (see <FIG>). The heat source unit control device <NUM> is electrically connected to a sensor (not shown) provided in the heat source unit <NUM>. The sensor includes, but is not limited to, a temperature sensor or a pressure sensor provided in the discharge pipe <NUM> and the suction pipe <NUM>, a temperature sensor provided in the heat source heat exchanger <NUM>, a temperature sensor provided in the liquid refrigerant pipe <NUM>, a temperature sensor that measures the temperature of the heat source air, and the like.

The heat source unit control device <NUM> is connected to the utilization unit control device <NUM> via the communication line <NUM>. By exchanging a control signal for the air conditioning apparatus <NUM> via the communication line <NUM>, the heat source unit control device <NUM> and the utilization unit control device <NUM> function as the control unit <NUM> that controls the operation of the air conditioning apparatus <NUM> described above. The control signal for the air conditioning apparatus <NUM> is a signal used to control various devices of the air conditioning apparatus <NUM>.

On receipt of an operation prohibition signal transmitted from the utilization unit control device <NUM> via the communication line <NUM>, the heat source unit control device <NUM> performs operation prohibition control on various devices of the heat source unit <NUM>. The operation prohibition signal will be described later. The operation prohibition control performed by the heat source unit control device <NUM> is control to prohibit at least the operation of the compressor <NUM>. In the operation prohibition control performed by the heat source unit control device <NUM>, the operation of the first fan <NUM> may also be prohibited in addition to the operation of the compressor <NUM>. In the present embodiment, the heat source unit control device <NUM> prohibits the operation of the compressor <NUM> and the first fan <NUM> as the operation prohibition control.

Specifically, the heat source unit control device <NUM> prohibits the activation of the compressor <NUM> and the first fan <NUM> of the nonoperational heat source unit <NUM> as the operation prohibition control. The heat source unit control device <NUM> may stop the compressor <NUM> and the first fan <NUM> of the heat source unit <NUM> in operation as the operation prohibition control. When stopping the compressor <NUM> and the first fan <NUM> of the heat source unit <NUM> in operation as the operation prohibition control, the heat source unit control device <NUM> may stop the compressor <NUM> and the first fan <NUM> in a similar manner to when the air conditioning operation is stopped normally. Alternatively, when stopping the compressor <NUM> and the first fan <NUM> of the heat source unit <NUM> in operation as the operation prohibition control, the heat source unit control device <NUM> may stop the compressor <NUM> and the first fan <NUM> in a manner different from when the air conditioning operation is stopped normally.

On receipt of a leakage detection signal transmitted from the utilization unit control device <NUM> via the communication line <NUM>, the heat source unit control device <NUM> performs leakage control on various devices of the heat source unit <NUM>. The leakage detection signal will be described later. The leakage control performed by the heat source unit control device <NUM> is, for example, control to prohibit activation of the compressor <NUM> and the first fan <NUM> of the nonoperational heat source unit <NUM>. The leakage control performed by the heat source unit control device <NUM> is control to stop the compressor <NUM> and the first fan <NUM> of the heat source unit <NUM> in operation. When stopping the compressor <NUM> and the first fan <NUM> of the heat source unit <NUM> in operation as the leakage control, the heat source unit control device <NUM> may stop the compressor <NUM> and the first fan <NUM> in a similar manner to when the air conditioning operation is stopped normally, or in a similar manner to the operation prohibition control. Alternatively, the heat source unit control device <NUM> may stop the compressor <NUM> and the first fan <NUM> in a manner different from when the air conditioning operation is stopped normally, or the operation prohibition control.

The utilization unit control device <NUM> includes a microcontroller unit (MCU) and various electric circuits and electronic circuits. The MCU includes a CPU, memory, I/O interface, and the like. Various programs to be executed by the CPU of the MCU are stored in the memory of the MCU. Note that various functions of the utilization unit control device <NUM> described below may be implemented by hardware, software, or hardware and software cooperating with each other. Part of various functions of the utilization unit control device <NUM> described below may be performed by a control device provided separately from the utilization unit control device <NUM>.

The utilization unit control device <NUM> is electrically connected to various devices of the utilization unit <NUM>, including the second expansion mechanism <NUM> and the second fan <NUM>, to control various devices of the utilization unit <NUM>. (See <FIG>). The utilization unit control device <NUM> is electrically connected to a sensor provided in the utilization unit <NUM> (not shown). The sensor includes, but is not limited to, a temperature sensor provided in the utilization heat exchanger <NUM> and the liquid side refrigerant pipe connected to the utilization heat exchanger <NUM>, a temperature sensor that measures the temperature of the air conditioning target space, and the like.

The utilization unit control device <NUM> is connected to the heat source unit control device <NUM> via the communication line <NUM> as described above. The utilization unit control device <NUM> is communicably connected to the remote controller <NUM> via the communication line <NUM>. The utilization unit control device <NUM> functions as the control unit <NUM> that controls the operation of the air conditioning apparatus <NUM>, together with the heat source unit control device <NUM> and the remote controller <NUM>.

The utilization unit control device <NUM> is electrically connected to the refrigerant detector <NUM> via a signal line <NUM>. Furthermore, the utilization unit control device <NUM> is electrically connected to the alarm device <NUM>, the ventilation device <NUM>, and the isolation valve <NUM> serving as safety devices via a signal line <NUM>.

The utilization unit control device <NUM> is configured to receive the detection signal output from the refrigerant detector <NUM>. The utilization unit control device <NUM> determines refrigerant leakage based on the detection signal output from the refrigerant detector <NUM>. On determination that the refrigerant is leaking, the utilization unit control device <NUM> transmits the leakage detection signal to the heat source unit control device <NUM> and the remote controller control device 48a.

Furthermore, on determination that the refrigerant is leaking, the utilization unit control device <NUM> performs leakage control on various devices of the utilization unit <NUM>. The leakage control performed by the utilization unit control device <NUM> is, for example, control to prohibit activation of the nonoperational second fan <NUM> of the utilization unit <NUM>. The leakage control performed by the utilization unit control device <NUM> is control to prohibit activation of the second fan <NUM> of the utilization unit <NUM> in operation. Note that when stopping the second fan <NUM> in operation as the leakage control, the utilization unit control device <NUM> may stop the second fan <NUM> in a similar manner to when the air conditioning operation is stopped normally, or in a similar manner to the operation prohibition control. Alternatively, the utilization unit control device <NUM> may stop the second fan <NUM> in a manner different from when the air conditioning operation is stopped normally, or the operation prohibition control.

The utilization unit control device <NUM> includes a safety device control unit <NUM> that controls the operation of the safety device as a functional unit. When the utilization unit control device <NUM> determines that the refrigerant is leaking based on the detection signal output from the refrigerant detector <NUM>, the safety device control unit <NUM> operates the safety device. For example, as the safety device in the air conditioning system <NUM>, it is assumed that the refrigerant detector <NUM> serving as the first device <NUM> and the alarm device <NUM> serving as the second device <NUM> are used. In this case, when refrigerant leakage is detected based on the signal output from the refrigerant detector <NUM>, the safety device control unit <NUM> transmits a signal for performing the operation when the refrigerant leakage is detected to the alarm device <NUM> via the signal line <NUM>.

Note that out of functions of the utilization unit control device <NUM>, details of the interlock function of the air conditioning apparatus <NUM> will be described later.

The remote controller <NUM> is a device for operating the air conditioning apparatus <NUM>. The remote controller <NUM>, whose installation position is not limited, is attached to a wall of the air conditioning target space, for example. The remote controller <NUM> is communicably connected to the utilization unit control device <NUM> via the communication line <NUM>.

The remote controller <NUM> includes the remote controller control device 48a including a microcontroller unit (MCU), and various electric circuits and electronic circuits. The remote controller control device 48a functions as the control unit <NUM> that controls the operation of the air conditioning apparatus <NUM>, together with the heat source unit control device <NUM> and the utilization unit control device <NUM>. The MCU includes a CPU, memory, I/O interface, and the like. Various programs to be executed by the CPU of the MCU are stored in the memory of the MCU. Note that various functions of the remote controller <NUM> described below may be implemented by hardware, software, or hardware and software cooperating with each other.

The remote controller <NUM> also includes an operation unit 48b and a display unit 48c.

The operation unit 48b is a functional unit into which a person inputs various commands for the air conditioning apparatus <NUM> and includes various switches and a touch panel.

The display unit 48c displays settings for the air conditioning apparatus <NUM> and a state of the air conditioning apparatus <NUM>. As the state of the air conditioning apparatus <NUM>, the display unit 48c displays that the operation of the air conditioning apparatus <NUM> is prohibited by the interlock function. Specifically, when the remote controller control device 48a receives the operation prohibition signal from the utilization unit control device <NUM>, the display unit 48c displays that the operation of the air conditioning apparatus <NUM> is prohibited by the interlock function. In addition, as the state of the air conditioning apparatus <NUM>, the display unit 48c displays that the operation of the air conditioning apparatus <NUM> is prohibited as a result of refrigerant leakage being detected by the refrigerant detector <NUM>. Specifically, when the remote controller control device 48a receives the leakage detection signal from the utilization unit control device <NUM>, the display unit 48c displays that the operation of the air conditioning apparatus <NUM> is prohibited because of the refrigerant leakage.

Next, the interlock function of the air conditioning apparatus <NUM> and the configuration related to the release thereof will be described with reference to <FIG>, <FIG>, <FIG>, and <FIG>. <FIG> is a schematic electrical circuit diagram for describing an interlock circuit <NUM> of the air conditioning apparatus <NUM>. <FIG> is an electrical circuit diagram for describing the first circuit <NUM> of the air conditioning apparatus <NUM>. <FIG> is a schematic electrical circuit diagram for describing another example of the interlock circuit <NUM> of the air conditioning apparatus <NUM>. <FIG> is an electrical circuit diagram for describing another example of the first circuit <NUM> of the air conditioning apparatus <NUM>.

First, the interlock function will be described. The interlock function here is a function of prohibiting the activation and operation of the air conditioning apparatus <NUM> when the safety devices required for the air conditioning system <NUM> are not supplied with power and are not operational.

The configuration to implement the interlock function will be described. The safety devices and the utilization unit control device <NUM> of the air conditioning apparatus <NUM> are connected by an interlocking electric wire to form the interlock circuit <NUM>. The utilization unit control device <NUM> supplies a current to the interlock circuit <NUM>. Note that each safety device includes a circuit configuration portion that constitutes part of the circuit of the interlock circuit <NUM>. In the circuit configuration portion of each safety device, a rheotome of the electric circuit exists. In the circuit configuration portion of each safety device, a switch is provided to connect the rheotome of the electric circuit of the circuit configuration portion when power is supplied to the safety device. As a result of such a configuration, when the safety devices and the utilization unit control device <NUM> are connected via the electric wire and power is supplied to the safety devices, a current flows through the interlock circuit <NUM>. Meanwhile, when any one of the safety devices and the utilization unit control device <NUM> are not connected via the electric wire, or when power is not supplied to any one of the safety devices, no current flows through the interlock circuit <NUM>. More specifically, when any one of the safety devices is not connected to the utilization unit control device <NUM>, or when power is not supplied to any one of the safety devices, the interlock circuit <NUM> is not formed (circuit is not closed) because the electric circuit includes the rheotome.

The utilization unit control device <NUM> detects whether or not a current is flowing through the interlock circuit <NUM>, and prohibits the operation of the utilization unit <NUM> and transmits the operation prohibition signal to the heat source unit control device <NUM> if no current flows through the interlock circuit <NUM>. Note that for the detection of whether or not a current is flowing through the interlock circuit <NUM>, for example, a relay, an ammeter, or a disconnection detector may be used, although not restrictive.

Note that the air conditioning system <NUM> may not require safety devices depending on the amount of refrigerant charged into the air conditioning apparatus <NUM>, the size of the air conditioning target space, the type of refrigerant charged into the air conditioning apparatus <NUM>, and the like. In that case, the interlock function of the air conditioning apparatus <NUM> is unnecessary. Therefore, the air conditioning apparatus <NUM> is configured to form the first circuit <NUM> by using the first member <NUM> described later. The air conditioning apparatus <NUM> is configured to be operational when a current flows through the first circuit <NUM>, even if there is no safety device and there is no electric wire connection between the safety device and the utilization unit control device <NUM> of the air conditioning apparatus <NUM>.

The connecting portion <NUM>, the circuit configuration portion <NUM>, the mounting portion <NUM>, and the first member <NUM>, which are the configuration to implement the interlock function and release thereof, will be described below. Note that although not restrictive, in the present embodiment, the connecting portion <NUM>, the circuit configuration portion <NUM>, and the mounting portion <NUM> are provided in the utilization unit <NUM>.

Note that as described above, the air conditioning system <NUM> of the present embodiment includes four types of safety devices. However, here, in order to avoid complicated description, excluding the case where the air conditioning system <NUM> does not require safety devices, the case where it is necessary to install two types of safety devices (first device <NUM> and second device <NUM>) will be described as an example. Here, the case where the first device <NUM> is the refrigerant detector <NUM> and the second device <NUM> is the alarm device <NUM> will be described as an example.

The connecting portion <NUM> is a portion to which electric wires connecting to the safety devices are connected. The connecting portion <NUM> includes a first electric wire connecting portion 85a and a second electric wire connecting portion 85b (see <FIG> and <FIG>). A first electric wire <NUM> having one end connected to the first device <NUM> is connected to the first electric wire connecting portion 85a. A first portion 97a and a coupling portion 97b described later of the circuit configuration portion <NUM> are connected to the first electric wire connecting portion 85a. A second electric wire <NUM> having one end connected to the second device <NUM> is connected to the second electric wire connecting portion 85b. The coupling portion 97b and a second portion 97c described later of the circuit configuration portion <NUM> are connected to the second electric wire connecting portion 85b. Note that if there are three or more safety devices, the number of electric wire connecting portions may be increased according to the number of safety devices.

The circuit configuration portion <NUM> is an electric circuit connecting the connecting portion <NUM> to the utilization unit control device <NUM>. The circuit configuration portion <NUM> constitutes the interlock circuit <NUM> together with the first electric wire <NUM> and the second electric wire <NUM>. The circuit configuration portion <NUM> includes the first portion 97a, the coupling portion 97b, and the second portion 97c, as show in <FIG> and <FIG>. The first portion 97a electrically connects the first electric wire connecting portion 85a to the utilization unit control device <NUM>. The coupling portion 97b electrically connects the first electric wire connecting portion 85a to the second electric wire connecting portion 85b. The second portion 97c electrically connects the second electric wire connecting portion 85b to the utilization unit control device <NUM>.

When the first electric wire <NUM> is connected to the first electric wire connecting portion 85a, the second electric wire <NUM> is connected to the second electric wire connecting portion 85b, and power is supplied to the first device <NUM> and the second device <NUM>, a current flows through the interlock circuit <NUM> in the order of the first portion 97a, the first electric wire <NUM> (part of reference sign 91a in <FIG> and <FIG>), the circuit configuration portion in the first device <NUM>, the first electric wire <NUM> (part of reference sign 91b), the coupling portion 97b, the second electric wire <NUM> (part of reference sign 92a), the circuit configuration portion in the second device <NUM>, the second electric wire <NUM> (part of reference sign 92b), and the second portion 97c.

The mounting portion <NUM> is a portion to which the first member <NUM> that can form the first circuit <NUM> without going through the first electric wire <NUM> and the second electric wire <NUM> is attached.

As one example, as shown in <FIG>, the mode in which the first member <NUM> is mounted in the mounting portion <NUM> when the interlock function is used will be described. The mounting portion <NUM> includes a contact connected to the first portion 97a of the circuit configuration portion <NUM> and a contact connected to the second portion 97c of the circuit configuration portion <NUM>. For example, the contact connected to the first portion 97a is pressed toward the contact connected to the second portion 97c. Part of the first member <NUM> is disposed between the contact connected to the first portion 97a and the contact connected to the second portion 97c when using the interlock function. Note that the first member <NUM> is preferably a single member integrally formed in order to improve workability during removal. The first member <NUM> here is made of, for example, an insulating material. Therefore, when the first member <NUM> exists between the contact connected to the first portion 97a and the contact connected to the second portion 97c, no current flows between the contact connected to the first portion 97a and the contact connected to the second portion 97c. When releasing the interlock function, by pulling out the first member <NUM>, the contact connected to the first portion 97a and the contact connected to the second portion 97c come into contact with each other, and the first circuit <NUM> different from the interlock circuit <NUM> is formed. The first circuit <NUM> is a circuit formed by short-circuiting the first portion 97a of the circuit configuration portion <NUM> and the second portion 97c of the circuit configuration portion <NUM>. When a current flows through the first circuit <NUM>, a current flows between the first portion 97a and the second portion 97c of the circuit configuration portion <NUM> as is the case where the interlock circuit <NUM> exists. Therefore, the utilization unit control device <NUM> permits the operation of the air conditioning apparatus <NUM>.

Next, as another example, a specific example of the mode will be described in which the first member <NUM> is not mounted in the mounting portion <NUM> when using the interlock function, as shown in <FIG>. The first member <NUM> here is, for example, a jumper cable or a short-circuit connector inserted into the mounting portion <NUM>. The mounting portion <NUM> includes a connecting portion connected to the first portion 97a of the circuit configuration portion <NUM> and a connecting portion connected to the second portion 97c of the circuit configuration portion <NUM>. The connecting portion connected to the first portion 97a of the circuit configuration portion <NUM> and the connecting portion connected to the second portion 97c of the circuit configuration portion <NUM> are not connected and are disposed apart from each other. When using the interlock function, the first member <NUM> is not attached to the mounting portion <NUM>. Therefore, no current flows between the connecting portion connected to the first portion 97a of the circuit configuration portion <NUM> and the connecting portion connected to the second portion 97c of the circuit configuration portion <NUM>. When releasing the interlock function, by connecting the connecting portion connected to the first portion 97a of the circuit configuration portion <NUM> and the connecting portion connected to the second portion 97c of the circuit configuration portion <NUM> by using the conductive first member <NUM>, the first circuit <NUM> different from the interlock circuit <NUM> is formed. The first circuit <NUM> is a circuit formed by short-circuiting the first portion 97a of the circuit configuration portion <NUM> and the second portion 97c of the circuit configuration portion <NUM>. When a current flows through the first circuit <NUM>, a current flows between the first portion 97a and the second portion 97c of the circuit configuration portion <NUM> as is the case where the interlock circuit <NUM> exists. Therefore, the utilization unit control device <NUM> permits the operation of the air conditioning apparatus <NUM>.

The air conditioning system <NUM> includes at least two types of safety devices as a measure against refrigerant leakage. As safety devices, the air conditioning system <NUM> of the present embodiment includes four types of safety devices (alarm device <NUM>, ventilation device <NUM>, isolation valve <NUM>, refrigerant detector <NUM>). The function of each safety device will be described later.

Note that when describing contents mainly related to the interlock function of the air conditioning apparatus <NUM> as described above, the air conditioning system <NUM> includes two types of devices, the first device <NUM> and the second device <NUM>, as safety devices. In the above example, the first device <NUM> is the refrigerant detector <NUM>, and the second device <NUM> is the alarm device <NUM>, but are not limited to this example.

For example, the first device <NUM> is any one of the alarm device <NUM>, the ventilation device <NUM>, the isolation valve <NUM>, and the refrigerant detector <NUM>. The second device <NUM> is any one of the alarm device <NUM>, the ventilation device <NUM>, the isolation valve <NUM>, and the refrigerant detector <NUM>, and is a type of device different from the first device <NUM>.

The number of safety devices included in the air conditioning system <NUM> is not limited to two. In addition to the first device <NUM> and the second device <NUM>, as the third device, for example, the air conditioning system <NUM> may include any one device of the alarm device <NUM>, the ventilation device <NUM>, the isolation valve <NUM>, and the refrigerant detector <NUM>, the device having a different type from the first device <NUM> and the second device <NUM>. In addition to the first device to the third device, as the fourth device, for example, the air conditioning system <NUM> may include any one device of the alarm device <NUM>, the ventilation device <NUM>, the isolation valve <NUM>, and the refrigerant detector <NUM>, the device having a different type from the first device to the third device.

The alarm device <NUM>, the ventilation device <NUM>, the isolation valve <NUM>, and the refrigerant detector <NUM>, which are safety devices, will be described below.

The refrigerant detector <NUM> detects whether or not the refrigerant exists around the refrigerant detector <NUM>. The refrigerant detector <NUM> is disposed in the casing of the utilization unit <NUM> (not shown) that houses the second expansion mechanism <NUM>, the utilization heat exchanger <NUM>, the second fan <NUM>, and the like. The refrigerant detector <NUM> may be disposed outside the casing of the utilization unit <NUM>.

The refrigerant detector <NUM> is, for example, a semiconductor sensor. The semiconductor refrigerant detector <NUM> includes a semiconductor detection element (not shown). The electric conductivity of the semiconductor detection element changes depending on whether or not the refrigerant gas exists nearby. As a result of having such a configuration, the refrigerant detector <NUM> outputs a relatively large current when the refrigerant gas exists around the semiconductor detection element.

Note that the refrigerant detector <NUM> is not limited to the semiconductor type, but is required at least to be a sensor that can detect refrigerant gas. For example, the refrigerant detector <NUM> may be an infrared sensor.

The signal detected by the refrigerant detector <NUM> is transmitted to the utilization unit control device <NUM> via the signal line <NUM>. The utilization unit control device <NUM> determines refrigerant leakage according to the magnitude of the current of the signal output from the refrigerant detector <NUM>.

The alarm device <NUM> is a safety device to notify refrigerant leakage when the refrigerant detector <NUM> detects the refrigerant leakage. Specifically, the alarm device <NUM> notifies the refrigerant leakage in response to the signal transmitted from the utilization unit control device <NUM> via the signal line <NUM>.

The alarm device <NUM> includes a lamp <NUM> for notifying the refrigerant leakage and a speaker <NUM> for notifying the refrigerant leakage.

A control device <NUM> of the alarm device <NUM> controls the operation of the lamp <NUM> and the speaker <NUM>. On receipt of the signal for causing the alarm device <NUM> to execute the notification operation of the refrigerant leakage, the signal being transmitted by the safety device control unit <NUM> of the utilization unit control device <NUM> via the signal line <NUM>, the control device <NUM> turns on the lamp <NUM> and outputs an alarm sound from the speaker <NUM>.

The ventilation device <NUM> mainly includes a ventilation fan <NUM>. A control device <NUM> of the ventilation device <NUM> controls the operation of the ventilation fan <NUM>.

The ventilation fan <NUM> is a fan to discharge air in a space where the refrigerant possibly leaks from the space. For example, the ventilation fan <NUM> is a fan to discharge air in the space where the utilization unit <NUM> in which the refrigerant detector <NUM> is disposed is installed from the space.

The ventilation device <NUM> operates when the refrigerant detector <NUM> detects refrigerant leakage. Specifically, the control device <NUM> starts the operation of the ventilation fan <NUM> in response to the signal for activating the ventilation fan <NUM>, the signal being transmitted by the safety device control unit <NUM> of the utilization unit control device <NUM> via the signal line <NUM>.

The isolation valve <NUM> includes the first isolation valve <NUM> provided in the liquid refrigerant connection pipe <NUM> and the second isolation valve <NUM> provided in the gas refrigerant connection pipe <NUM>. The first isolation valve <NUM> and the second isolation valve <NUM> are, but are not limited to, electromagnetic valves or motor operated valves, for example. A control device <NUM> controls the operation of the first isolation valve <NUM> and the second isolation valve <NUM>. Normally, the first isolation valve <NUM> and the second isolation valve <NUM> are in the open state. The isolation valve <NUM> closes the first isolation valve <NUM> and the second isolation valve <NUM> when the refrigerant detector <NUM> detects refrigerant leakage. Specifically, the control device <NUM> closes the first isolation valve <NUM> and the second isolation valve <NUM> in response to the signal for closing the first isolation valve <NUM> and the second isolation valve <NUM>, the signal being transmitted by the safety device control unit <NUM> of the utilization unit control device <NUM> via the signal line <NUM>.

In the air conditioning apparatus <NUM> of the present embodiment, the first circuit <NUM> can be formed by removing the first member <NUM>, and the interlock with a plurality of safety devices can be quickly released. Since the first member <NUM> is normally attached to the mounting portion <NUM> when the air conditioning apparatus <NUM> is installed, the possibility of loss of the first member <NUM> can be reduced.

Instead, in the air conditioning apparatus <NUM>, the first circuit <NUM> may be formed by attaching the first member <NUM> to the mounting portion <NUM>. In such an air conditioning apparatus <NUM>, the first circuit <NUM> can be formed by attaching the first member <NUM>, and the interlock with a plurality of safety devices can be quickly released.

Next, modifications of the air conditioning apparatus <NUM> according to the present embodiment will be described. Note that constituent elements similar to those described in the embodiment are denoted with similar reference signs, and the detailed description thereof will be omitted.

In the above embodiment, the display unit 48c of the remote controller <NUM> notifies that the operation of the utilization unit <NUM> or the heat source unit <NUM> is prohibited. However, this is not restrictive.

The air conditioning system <NUM> may notify a mobile terminal or the like owned by an administrator of the air conditioning system <NUM> or the like via a communication line such as the Internet that the operation of at least one of the utilization unit <NUM> and the heat source unit <NUM> is prohibited.

The air conditioning system <NUM> may include, as a notification unit, an LED lamp disposed on the casing of the utilization unit <NUM> for notifying that the operation of the heat source unit <NUM> is prohibited.

For example, the alarm device <NUM> may include only one of the lamp <NUM> and the speaker <NUM> as means for making a notification of refrigerant leakage. The alarm device <NUM> may include another means for making a notification of refrigerant leakage, for example a vibration device, other than the lamp <NUM> and the speaker <NUM>.

The lamp <NUM> and the speaker <NUM> of the alarm device <NUM> for notifying refrigerant leakage may be provided in the remote controller <NUM> or the utilization unit <NUM>.

In the above embodiment, the interlock circuit <NUM> is a circuit in which the utilization unit control device <NUM>, the first device <NUM>, and the second device <NUM> are connected in series by the first electric wire <NUM> and the second electric wire <NUM>. However, this is not restrictive. As shown in <FIG>, for example, the interlock circuit <NUM> may include a first interlock circuit 98a and a second interlock circuit 98b that are independent of each other.

In the first interlock circuit 98a, the utilization unit control device <NUM> is connected to the first electric wire connecting portion 85a via the circuit configuration portion <NUM>, and the first electric wire connecting portion 85a is connected to the first device <NUM> via the first electric wire <NUM>. In the second interlock circuit 98b, the utilization unit control device <NUM> is connected to the second electric wire connecting portion 85b via the circuit configuration portion <NUM>, and the second electric wire connecting portion 85b is connected to the second device <NUM> via the second electric wire <NUM>.

When using the interlock function, the utilization unit control device <NUM> in the example of <FIG> prohibits the operation of the air conditioning apparatus <NUM> when no current flows through at least one of the first interlock circuit 98a and the second interlock circuit 98b. In other words, the utilization unit control device <NUM> permits the operation of the air conditioning apparatus <NUM> when a current flows through both the first interlock circuit 98a and the second interlock circuit 98b.

In this way, when the interlock circuit <NUM> includes the first interlock circuit 98a and the second interlock circuit 98b that are independent of each other, the first member <NUM> is required at least, for example, to be a member that short-circuits all of the connecting portion of the first electric wire <NUM> for the first electric wire connecting portion 85a, and the connecting portion of the second electric wire <NUM> for the second electric wire connecting portion 85b. The first circuit <NUM> formed as a result includes two circuits (first circuit A 99a and first circuit B 99b). When the first member <NUM> is mounted in the connecting portion <NUM> serving as the mounting portion and a current flows through both the first circuit A 99a and the first circuit B 99b, the utilization unit control device <NUM> permits the operation of the air conditioning apparatus <NUM>.

Claim 1:
An air conditioning apparatus (<NUM>) including a refrigerant circuit (<NUM>), the air conditioning apparatus comprising:
a first device (<NUM>) of a plurality of safety devices including at least two types of a refrigerant detector, an alarm device, an isolation valve, and a ventilation device;
a second device (<NUM>) of a type different from the first device of the plurality of safety devices;
a connecting portion (<NUM>) including a first electric wire connecting portion (85a) and a second electric wire connecting portion (85b);
a first electric wire (<NUM>) connected to the first device (<NUM>) and to the first electric wire connecting portion (85a);
a second electric wire (<NUM>) connected to the second device (<NUM>) and to the second electric wire connecting portion (85b);
a control unit (<NUM>, <NUM>);
a circuit configuration portion (<NUM>) including
a first portion (97a) that electrically connects the first electric wire connecting portion (85a) to the control unit (<NUM>, <NUM>),
a second portion (97c) that electrically connects the second electric wire connecting portion (85b) to the control unit (<NUM>, <NUM>), and
a coupling portion (97b) that electrically connects the first electric wire connecting portion (85a) to the second electric wire connecting portion (85b);
an interlock circuit (<NUM>, 98a, 98b) formed by the circuit configuration portion (<NUM>) together with the first electric wire (<NUM>) and the second electric wire (<NUM>) connected to the connecting portion (<NUM>);
a first member (<NUM>) that enables formation of a first circuit (<NUM>, 99a, 99b) including at least part of the circuit configuration portion (<NUM>) without going through the first electric wire (<NUM>) and the second electric wire (<NUM>);
wherein the first circuit (<NUM>, 99a, 99b) is a circuit formed by short-circuiting the first portion (97a) of the circuit configuration portion (<NUM>) and the second portion (97c) of the circuit configuration portion (<NUM>), and
wherein the control unit (<NUM>, <NUM>) is configured to prohibit an operation of the air conditioning apparatus when no current flows through either the interlock circuit or the first circuit.