JP2015212600A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner capable of preventing a failure that a leaked slightly flammable refrigerant reaches flammable concentration.SOLUTION: When a refrigerant circulating between an indoor unit disposed on a ceiling plane and an outdoor unit leaks, an air conditioner discharges air in a rear side space of the ceiling plane to the exterior of the space.

Description

  Embodiments described herein relate generally to an air conditioner having a ceiling-mounted indoor unit.

  In the case of an air conditioner having a ceiling-mounted indoor unit, refrigerant piping that connects the indoor unit and the outdoor unit is disposed in the ceiling space.

  In the case of an air conditioner installed in a large building, since a long refrigerant pipe is required, a plurality of refrigerant pipes are added and connected in the ceiling space.

JP2011-226715A

  The refrigerant may leak from a connection portion between the indoor unit and the refrigerant pipe or a joint of each refrigerant pipe in the ceiling space.

  The R32 refrigerant used in recent air conditioners has a low global warming potential compared to the R410A refrigerant, but has a slight flammability, and therefore may ignite at a predetermined concentration. When such a slightly flammable refrigerant leaks into the ceiling space, since the ceiling space is narrow, the leaked refrigerant may reach a flash concentration.

  The objective of embodiment of this invention is providing the air conditioner which can prevent the malfunction that the slightly flammable refrigerant | coolant which leaked reaches a flash concentration.

  An air conditioner according to a first aspect includes an indoor unit disposed on a ceiling surface, and circulates a refrigerant between the indoor unit and the outdoor unit, and includes an exhaust unit. When the refrigerant leaks, the exhaust unit discharges the air in the space behind the ceiling surface to the outside of the space.

The perspective view which shows the external appearance of one Embodiment. The figure which shows the longitudinal cross-section of the indoor unit of the embodiment. The figure which shows the state which the damper of FIG. 2 opened. The figure which shows the refrigerating cycle and control part of the embodiment. The flowchart which shows the control of the same embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In FIG. 1, a ceiling surface mounting type (also referred to as a ceiling cassette type) indoor unit 1 disposed on the ceiling surface is a rectangular frame-shaped decorative panel 2 facing the indoor space, and a rectangular shape disposed inside the decorative panel 2. A suction panel 3 having a shape and a plurality of air outlets 4 formed between each side of the outer peripheral edge of the suction panel 3 and each side of the inner peripheral edge of the decorative panel 2 are provided.

  A cable 31 is led out from a control unit 70 (described later) housed in the main body of the indoor unit 1, and a remote control type operating device (referred to as a remote controller) 30 is connected to the cable 31.

  One end of each of the liquid side refrigerant pipe 41 and the gas side refrigerant pipe 42 is connected to a pipe connection portion in the main body of the indoor unit 1, and the other end of the liquid side refrigerant pipe 41 and the gas side refrigerant pipe 42 is connected to the outdoor outdoor unit 40. Connected to the pipe connection. When the distance between the indoor unit 1 and the outdoor unit 40 is long, the liquid-side refrigerant pipe 41 and the gas-side refrigerant pipe 42 are configured by adding and connecting a plurality of refrigerant pipes. The additional connection of each refrigerant pipe is sealed, for example, by a “brazing” process.

  As shown in FIG. 2, the main body of the indoor unit 1 is embedded in an opening formed in the ceiling surface 21 of the air-conditioned room in the building. With this embedding, the decorative panel 2, the suction panel 3, and the air outlets 4 face the indoor space A of the air-conditioned room. Each outlet 4 has a louver 4a for adjusting the outlet direction. The ceiling space B on the back side of the ceiling surface 21 is a narrow space surrounded by the ceiling surface 21, the side wall 22, and the upper floor 23.

  An indoor fan 5 and a drive motor 5M for the indoor fan 5 are disposed in the main body of the indoor unit 1, and a suction duct 6 is disposed between the indoor fan 5 and the suction panel 3. A suction air passage 7 is formed inside the suction duct 6.

  In the main body of the indoor unit 1, an indoor heat exchanger 8 is disposed around the indoor fan 5, and a blowout air passage 9 is formed between the indoor heat exchanger 8 and the inner peripheral surface of the main body casing. The blowout air passage 9 communicates with each air outlet 4.

  When the indoor fan 5 is operated, as indicated by an arrow, the air in the indoor space A on the front side of the ceiling surface 21 flows into the suction air passage 7 in the suction duct 6 through the suction panel 3. The air that has flowed into the suction air passage 7 passes through the indoor fan 5, and further flows through the indoor heat exchanger 8 into the blowout air passage 9. The air that has flowed into the blowout air passage 9 is blown into the indoor space A from each blowout port 4.

  In the main body housing of the indoor unit 1, at least one vent hole 1 a is formed at a position corresponding to the blowout air passage 9. The vent 1a communicates the blowing air passage 9 and the ceiling back space B. A damper 11 is pivotally supported by the vent 1a so as to be opened and closed, and the damper 11 is connected to a motor 13 via an opening / closing mechanism 12. When the motor 13 rotates in the forward direction, the power is transmitted to the damper 11 via the opening / closing mechanism 12, and the damper 11 is opened as shown in FIG. When the damper 11 is opened, the vent 1a is opened, and the air in the ceiling back space B flows into the blowout air passage 9 through the vent 1a. When the motor 13 rotates in reverse, the power is transmitted to the damper 11 via the opening / closing mechanism 12, and the damper 11 is closed as shown in FIG. When the damper 11 is closed, the vent 1a is closed.

  FIG. 4 shows the heat pump refrigeration cycle configured from the indoor unit 1 to the outdoor unit 40 and the control unit 70 accommodated in the indoor unit 1.

  First, in the outdoor unit 40, an outdoor heat exchanger 53 is connected to the discharge port of the compressor 51 via a four-way valve 52, and a packed valve 55 is connected to the outdoor heat exchanger 53 via an electric expansion valve 54. Is done. The indoor heat exchanger 8 of the indoor unit 1 is connected to the packed valve 55 via the liquid side refrigerant pipe 41, and the outdoor unit 40 packed valve 56 is connected to the indoor heat exchanger 8 via the gas side refrigerant pipe 42. Piping is connected. The intake port of the compressor 51 is connected to the packed valve 56 through the four-way valve 52 and the accumulator 57 by piping.

  The compressor 51 sucks the refrigerant from the suction port, compresses the suction refrigerant, and discharges it from the discharge port. As the refrigerant, for example, R32 refrigerant which is a refrigerant having a smaller global warming potential than R410A is used. This refrigerant is slightly flammable and easily ignites (or ignites) at a predetermined concentration. An inverter 50 is connected to the compressor 51. The inverter 50 converts the voltage of the commercial AC power source into a DC voltage, converts the DC voltage into a predetermined frequency F (Hz) and a level AC voltage corresponding to the predetermined frequency F by switching, and outputs the AC voltage. With this output, the compressor 51 operates. The electric expansion valve 54 is a pulse motor valve (PMV) whose opening degree changes continuously according to the number of input drive pulses. An outdoor fan 58 is disposed in the vicinity of the outdoor heat exchanger 53.

  At the time of cooling, as indicated by arrows, the refrigerant discharged from the compressor 51 is a four-way valve 52, an outdoor heat exchanger 53, an electric expansion valve 54, a packed valve 55, a liquid side refrigerant pipe 41, an indoor heat exchanger 8, The refrigerant is sucked into the compressor 51 through the gas side refrigerant pipe 42, the packed valve 56, the four-way valve 52, and the accumulator 57. With this refrigerant flow, the outdoor heat exchanger 53 functions as a condenser and the indoor heat exchanger 8 functions as an evaporator. At the time of heating, the flow path of the four-way valve 52 is switched so that the refrigerant discharged from the compressor 51 causes the four-way valve 52, the packed valve 56, the gas side refrigerant pipe 42, the indoor heat exchanger 8, and the liquid side refrigerant pipe 41. , The packed valve 55, the electric expansion valve 54, the outdoor heat exchanger 53, the four-way valve 52, and the accumulator 57 are sucked into the compressor 51. With this refrigerant flow, the indoor heat exchanger 8 functions as a condenser, and the outdoor heat exchanger 53 functions as an evaporator.

  A temperature sensor 61 is attached to the outdoor heat exchanger 53. A temperature sensor 62 is attached to a position of the indoor heat exchanger 8 on the cooling medium inflow side. A temperature sensor 63 is attached to the pipe between the four-way valve 52 and the accumulator 57.

  The control unit 70 controls the indoor unit 1 and the outdoor unit 40. The controller 70 is connected to the remote controller 30 via the cable 31 and is connected to a push button type and automatic reset type reset switch 71. The remote controller 30 is for setting operating conditions of the air conditioner. The reset switch 71 is disposed on a control circuit board on which the control unit 70 is mounted.

The control unit 70 includes the following means (1) to (3) as main functions.
(1) Superheat degree which controls the opening degree of the electric expansion valve 54 so that the superheat degree SH of the refrigerant in the evaporator (the indoor heat exchanger 8 during cooling and the outdoor heat exchanger 53 during heating) becomes the target value SHt. Control means. The superheat degree SH is a difference (= T3−T2) between the detected temperature T2 of the temperature sensor 62 and the detected temperature T3 of the temperature sensor 63 during cooling, and the detected temperature T1 of the temperature sensor 61 and the detected temperature of the temperature sensor 63 during heating. It is a difference (= T3−T1) from the detected temperature T3.

  (2) Detection means for detecting refrigerant leakage in the heat pump refrigeration cycle.

  (3) Control means for closing the damper 11 when the detection means does not detect refrigerant leakage and opening the damper 11 when the detection means detects refrigerant leakage.

  When the refrigerant leaks by the detection means (2), the control means (3), the vent 1a, the damper 11, the opening / closing mechanism 12, the motor 13, etc., the air in the ceiling space B is supplied. An exhaust means for discharging is configured. The discharge destination is the indoor space A having a larger capacity than the ceiling space B.

  Specifically, the detection means of (2) described above is based on the current opening of the electric expansion valve 54 when there is no refrigerant leakage in the heat pump refrigeration cycle and the initial state quantity of the heat pump refrigeration cycle and the current heat pump type. Prediction is performed based on the amount of change in the refrigeration cycle state quantity, and the presence or absence of actual refrigerant leakage is detected by comparing the predicted opening degree Qm with the current actual opening degree Qa of the electric expansion valve 54. For prediction, the state of the heat pump refrigeration cycle in the initial operation of the heat pump refrigeration cycle is stored in the internal memory as an initial state, and the difference between the stored initial state and the current state of the heat pump refrigeration cycle is the amount of state change. And the current opening of the electric expansion valve 54 when there is no refrigerant leakage in the heat pump refrigeration cycle is predicted based on the detected state change amount. The elements stored as the initial state are the opening Qa ′ of the electric expansion valve 54 that is essential, and the operation frequency (output frequency of the inverter 50) F ′, the condensation temperature Tc ′, the evaporation temperature Te ′, and the superheat degree SH ′. At least one. In the case where the operation frequency F ′, the condensation temperature Tc ′, the evaporation temperature Te ′, and the superheat degree SH ′ are the elements of the initial state, similarly, the operation frequency F, the condensation temperature Tc, the evaporation temperature Te, and the superheat degree are the same. Four SHs are extracted as the current state. When any three of the operation frequency F ′, the condensation temperature Tc ′, the evaporation temperature Te ′, and the superheat degree SH ′ are the initial state elements, the same three elements are extracted as the current state. When any two of the elements are in the initial state, the same two elements are extracted as the current state. If any one of the elements is in the initial state, the same one element is extracted as the current state.

Next, the control executed by the control unit 70 will be described with reference to the flowchart of FIG.
The controller 70 determines whether or not the initial state flag f is “0” (step S1). The initial state flag f is reset to “0” in response to an ON operation of the reset switch 71 by a user or an operator when the air conditioner is installed.

  When the initial state flag f is “0” (YES in step S1), the control unit 70 causes the motor 13 of the indoor unit 1 to reversely rotate and closes the damper 11 of the vent 1a (step S2). By closing the damper 11, the vent 1a is closed. Then, the control unit 70 integrates the operation time t (step S3), and determines whether the integrated operation time t is equal to or longer than the set time t1 (t ≧ t1) (step S4). The accumulated operation time t is sequentially updated and stored in the memory in the control unit 70 and cleared to zero when the reset switch 71 is turned on. The set time t1 is 10 to 50 hours in the initial stage of operation, and an appropriate value is selected according to the installation environment of the apparatus.

  When the integrated operation time t is not longer than the set time t1 (NO in step S4), the control unit 70 returns to the flag determination in step S1. When the accumulated operation time t is equal to or longer than the set time t1 (YES in step S4), the control unit 70 determines whether or not the heat pump refrigeration cycle is in a stable state (steps S5, S6, and S7).

  In step S5, it is determined whether the absolute value ΔSH of the difference between the superheat degree SH and the target value SHt is less than the set value ΔSHs (| ΔSH | <ΔSHs). The set value ΔSHs is, for example, 2 to 3K. In step S6, it is determined whether the superheat degree SH is equal to or greater than a set value SH (SH ≧ SHA). The set value SHa is, for example, 1 to 2K. In this case, the superheat degree SH is equal to or greater than the set value SHa, and the superheat degree SH is a positive value. In step S7, it is determined whether the operating frequency (output frequency of the inverter 50) F of the compressor 51 is equal to or higher than the set value Fs (F ≧ Fs). The set value Fs is, for example, 30 Hz.

  If any one of the determination results in steps S5, S6, and S7 is negative, the control unit 70 returns to the flag determination in step S1.

  When the determination results of steps S5, S6, and S7 are both affirmative, the control unit 70 stores the initial state of the heat pump refrigeration cycle in the internal memory under the determination that the heat pump refrigeration cycle has entered a stable state ( Step S8). In this case, the opening degree Q ′, the operation frequency F ′, the condensing temperature Tc ′, the evaporation temperature Te ′, and the superheat degree SH ′ are stored as initial states. The condensation temperature Tc ′ is a detection temperature T1 of the temperature sensor 61 attached to the outdoor heat exchanger 53 during cooling, and is a detection temperature T2 of the temperature sensor 62 attached to the indoor heat exchanger 8 during heating. The evaporation temperature Te ′ is a detection temperature T2 of the temperature sensor 62 attached to the indoor heat exchanger 8 during cooling, and is a detection temperature T1 of the temperature sensor 61 attached to the outdoor heat exchanger 53 during heating.

  As the initial state is stored, the control unit 70 sets the initial state flag f to “1” (step S9), and then returns to the flag determination of step S1.

  When the initial state flag f is “1” (NO in step S1), the control unit 70 determines whether or not the heat pump refrigeration cycle is in a stable state as in the case of storing the initial state (step S10, S11, S12).

  In step S10, it is determined whether the absolute value ΔSH of the difference between the superheat degree SH and the target value SHt is less than the set value ΔSHs (| ΔSH | <ΔSHs). The set value ΔSHs is, for example, 2 to 3K. In step S11, it is determined whether the degree of superheat SH is equal to or greater than a set value SH (SH ≧ SHA). The set value SHa is, for example, 1 to 2K. In this case, the superheat degree SH is equal to or greater than the set value SHa, and the superheat degree SH is a positive value. In step S12, it is determined whether the operating frequency F of the compressor 51 is equal to or higher than a set value Fs (F ≧ Fs). The set value Fs is, for example, 30 Hz.

  If any one of the determination results in steps S10, S11, and S12 is negative, the control unit 70 returns to the flag determination in step S1.

  When the determination results of steps S10, S11, and S12 are all affirmative, the control unit 70 determines that the heat pump refrigeration cycle has entered a stable state, and stores the initial state and the current time of the heat pump refrigeration cycle. A difference from the state is detected as a state change amount (step S13). In this case, the operation frequency F, the condensation temperature Tc, the evaporation temperature Te, and the superheat degree SH are extracted as the current state.

  The state change amount includes a difference ΔF between the operation frequency F ′ in the initial state and the current operation frequency F, a difference ΔTc between the condensation temperature Tc ′ in the initial state and the current condensation temperature Tc, and the evaporation temperature Te in the initial state. The difference ΔTe between ′ and the current evaporation temperature Te, and the difference ΔSHx between the superheat degree SH ′ in the initial state and the current superheat degree SH.

The controller 70 predicts the current opening degree Qm of the electric expansion valve 54 when there is no refrigerant leakage in the heat pump refrigeration cycle based on the detected state change amount (step S14). This prediction will be described.
First, as factors that determine the opening degree Q of the electric expansion valve 54, there are “a degree of degree”, “circulation amount”, “evaporation temperature Te”, and “condensation temperature Tc”. “Dew degree” is the weight ratio of steam (dry saturated steam) to saturated liquid when the refrigerant is wet saturated steam. The “circulation amount” is the circulation amount of the refrigerant.

From these factors, the following theoretical formula representing the opening degree Q of the electric expansion valve 54 is obtained. L is the circulation amount, and ρ is the refrigerant density on the refrigerant inlet side of the electric expansion valve 54. ΔP is a difference between the refrigerant pressure P1 on the refrigerant inlet side of the electric expansion valve 54 and the refrigerant pressure P2 on the refrigerant outlet side.
Q = L · (ρ / ΔP) ^ 0.5
The circulation amount L and the pressure difference ΔP excluding the refrigerant density ρ can be obtained by calculation using the operating frequency F, the condensation temperature Tc, the evaporation temperature Te, and the superheat degree SH. If the opening Q is corrected using the operating frequency F, the condensation temperature Tc, the evaporation temperature Te, and the superheat degree SH as parameters, the amount of change in the refrigerant density ρ is known from the amount of change in the opening Q after the correction and before the correction. Can do. The change amount of the refrigerant density ρ is also the change amount of the refrigerant in the refrigeration cycle.

Accordingly, the refrigerant leaks into the heat pump refrigeration cycle by calculating the opening degree Q ′ stored as the initial state using the following equation that corrects the operating frequency F, the condensation temperature Tc, the evaporation temperature Te, and the state change amount of the superheat degree SH as parameters. It is possible to predict the current opening degree Qm of the electric expansion valve 54 when there is no valve. a, b, c, and d are constants.
Qm = a · ΔF + b · ΔTc + c · ΔTe + d · ΔSHx + Q ′
If there is refrigerant leakage in the heat pump refrigeration cycle, the actual opening Qa of the electric expansion valve 54 is adjusted in an increasing direction with respect to the predicted opening Qm in order to compensate for the shortage of refrigerant flow due to the leakage.

  The control unit 70 obtains a deviation amount ΔQ (= Qa−Qm) between the detected predicted opening degree Qm and the current actual opening degree Qa of the electric expansion valve 54 (step S15), and the obtained deviation amount ΔQ is the set value ΔQs. It is determined whether this is the case (step S16). The set value ΔQs is, for example, an opening of 100 pulses to 200 pulses as the number of drive pulses, and an appropriate value is selected according to the capacity of the refrigeration cycle equipment, the pipe length, and the like.

  When the deviation amount ΔQ is equal to or larger than the set value ΔQs (YES in step S16), the control unit 70 rotates the motor 13 of the indoor unit 1 in the normal direction based on the determination that the refrigerant leaks in the heat pump refrigeration cycle. Then, the damper 11 of the indoor unit 1 is opened (step S17). When the damper 11 is opened, the air in the ceiling space B flows into the blowing air passage 9 through the vent 1a. The air that has flowed in is blown into the indoor space A from each outlet 4 together with the air-conditioning air that has passed through the indoor heat exchanger 8.

  When the location of the refrigerant leakage is a connection portion between the main body housing of the indoor unit 1 and the liquid side refrigerant pipe 41 or a joint of the plurality of liquid side refrigerant pipes 41 in the ceiling space B, the leaked liquid refrigerant is vaporized. Floating in the ceiling space B. When the location of the refrigerant leak is a connection portion between the main body housing of the indoor unit 1 and the gas-side refrigerant pipe 42 or a joint of the plurality of gas-side refrigerant pipes 42 in the ceiling space B, the leaked gas refrigerant is behind the ceiling. Drift in space B. In this case, since the ceiling space B is narrow, there is a possibility that the gas refrigerant drifting in the ceiling space B will increase in concentration and reach the ignition concentration (or ignition concentration).

  However, when this refrigerant leaks, it is detected and the damper 11 is opened, so that the gas refrigerant drifting in the ceiling space B flows into the blowout air passage 9 in the indoor unit 1 through the vent hole 1a of the indoor unit 1. The inflowing gas refrigerant is blown into the indoor space A from each outlet 4 together with the air-conditioning air that has passed through the indoor heat exchanger 8.

  Since the indoor space A is considerably larger than the ceiling space B, the gas refrigerant blown into the indoor space A together with the air-conditioning air diffuses in the indoor space A and is reduced in concentration. Therefore, the refrigerant that has leaked into the ceiling space B does not reach the flash point and is safe.

  As the damper 11 is opened, the control unit 70 notifies that the refrigerant has leaked, for example, by displaying characters or displaying an icon image on the remote controller 30 (step S18). By this notification, the user can recognize that a refrigerant leak has occurred and request maintenance / inspection.

  Moreover, the control part 70 stops the compressor 51 with a notification, and prohibits subsequent operation | movement (step S19). By prohibiting this operation, the operation does not continue with the refrigerant leaking, and adverse effects on the refrigeration cycle equipment can be avoided.

  If the location of the refrigerant leak is not in the ceiling space B, the damper 11 is opened even though there is no refrigerant in the ceiling space B. However, if the refrigerant leaks, the compressor 51 is stopped and the subsequent operation is performed. Therefore, there is no inconvenience even if the damper 11 is opened.

  After repairing the refrigerant leakage, the operator turns on the reset switch 71. When the reset switch 71 is turned on, the control unit 70 erases the initial state stored in the internal memory, and stores the initial state after the start of a new operation in the internal memory. Thus, by updating the initial state, the leakage of the refrigerant can be reliably detected even after the relocation.

  Further, the control unit 70 resets the initial state flag f to “0” in response to the ON operation of the reset switch 71. Thereby, when restarting the operation after the repair, the control unit 70 can perform a process of closing the damper 11 of the indoor unit 1 (YES in step S1, step S2).

  In the above embodiment, the current opening degree of the electric expansion valve 54 when there is no refrigerant leakage in the heat pump refrigeration cycle is the amount of change between the initial state quantity of the heat pump refrigeration cycle and the current heat pump refrigeration cycle state quantity. The refrigerant leakage of the heat pump refrigeration cycle is detected by comparing the predicted opening Qm with the current actual opening Qa of the electric expansion valve 54. However, the present invention is not limited to this, and other detection means May be adopted. For example, it is good also as a structure which arrange | positions a gas sensor and a liquid sensor in the ceiling back space B, and detects the leak of a gas refrigerant or a liquid refrigerant by this gas sensor.

  In the above embodiment, one vent hole 1 a is formed in the main body housing of the indoor unit 1, but a plurality of, for example, four vent holes 1 a may be formed at positions corresponding to the respective outlets 4.

  In the above embodiment, the reset switch 71 is arranged on the control circuit board on which the control unit 70 is mounted. However, the reset switch 71 may be provided on the remote controller 30.

  In addition, the said embodiment and modification are shown as an example and are not intending limiting the range of invention. The novel embodiments and modifications can be implemented in various other forms, and various omissions, rewrites, and changes can be made without departing from the spirit of the invention. In these embodiments and modifications, the scope of the invention is included in the gist, and is included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Indoor unit, 1a ... Vent, 2 ... Makeup panel, 3 ... Suction panel, 4 ... Air outlet, 5 ... Indoor fan, 5M ... Drive motor, 6 ... Suction duct, 7 ... Suction air path, 8 ... Indoor heat Exchanger, 9 ... Air outlet, 11 ... Damper, 12 ... Opening / closing mechanism, 13 ... Motor, 21 ... Ceiling surface, 22 ... Side wall, 23 ... Upper floor, A ... Indoor space, B ... Back space, 40 ... Outdoor unit, 41 ... Liquid side refrigerant pipe, 42 ... Gas side refrigerant pipe, 50 ... Inverter, 51 ... Compressor, 52 ... 4-way valve, 53 ... Outdoor heat exchanger, 54 ... Electric expansion valve, 57 ... Accumulator, 11 ... Outdoor fan, 12 ... indoor fan, 21, 22, 23 ... temperature sensor, A ... outdoor unit, B ... indoor unit, 30 ... remote control, 70 ... control unit, 71 ... reset switch

Claims (3)

In an air conditioner that includes an indoor unit disposed on a ceiling surface and circulates a refrigerant between the indoor unit and the outdoor unit,
When the refrigerant leaks, exhaust means for discharging the air in the back side space of the ceiling surface to the outside of the space,
An air conditioner comprising: 2. The air conditioner according to claim 1, wherein, when the refrigerant leaks, the exhaust unit discharges air in a space behind the ceiling surface to an indoor space on the front side of the ceiling surface. The exhaust means includes
A ventilation hole formed in the casing of the indoor unit, and communicating the blowing air passage in the indoor unit and the back side space of the ceiling surface;
A damper that opens and closes the vent;
Detecting means for detecting leakage of the refrigerant;
Control means for closing the damper when the detection means does not detect refrigerant leakage, and for opening the damper when the detection means detects refrigerant leakage;
The air conditioner according to claim 1, comprising:

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