JP7713639B2 - Air Conditioning Equipment - Google Patents

Description

This disclosure relates to air conditioning devices.

Conventionally, technology for detecting refrigerant leakage in air conditioners is known (see, for example, Patent Document 1). The air conditioner described in Patent Document 1 is equipped with a semiconductor-type first refrigerant detection sensor that detects refrigerant leakage, a second refrigerant detection sensor that detects refrigerant leakage using a detection method different from that of the first refrigerant detection sensor, and a control unit that controls the operation of the first refrigerant detection sensor and the second refrigerant detection sensor. In Patent Document 1, the control unit controls the first refrigerant detection sensor to heat and operate it while the air conditioner is operating, and controls the second refrigerant detection sensor to operate while the air conditioner is stopped. In this way, Patent Document 1 suppresses deterioration over time of the semiconductor-type first refrigerant detection sensor.

JP 2017-180927 A

This disclosure provides an air conditioner that can ensure safety while allowing the refrigerant detection sensor to be used for a long period of time.

The air conditioning apparatus of the present disclosure comprises an outdoor unit equipped with a compressor, an indoor unit, a refrigerant detection sensor provided in the indoor unit for detecting refrigerant leakage, and a control unit for controlling the operation of the refrigerant detection sensor, in which the control unit controls the ratio of time that electricity is applied to the refrigerant detection sensor , and the control unit executes intermittent power control to intermittently apply power to the refrigerant detection sensor, and the time that power is not applied to the refrigerant detection sensor during the intermittent power control is within the time after refrigerant leakage from a refrigerant piping that it is necessary to detect the refrigerant leakage .

This disclosure makes it possible to ensure safety while allowing the refrigerant detection sensor to be used for a long period of time.

FIG. 1 is a side cross-sectional view showing an indoor unit according to a first embodiment. FIG. 1 is a plan view showing an indoor unit according to a first embodiment. FIG. 1 is a schematic diagram showing a refrigerant detection sensor according to a first embodiment; Refrigeration cycle diagram showing an air conditioner according to embodiment 1 FIG. 1 is a block diagram showing a control configuration according to a first embodiment. Timing chart of compressor operation and refrigerant detection sensor energization control Diagram explaining non-energized time Flowchart showing the process flow of the control unit

(Foundations and other information that form the basis of this disclosure)
At the time the inventors came up with the idea of this disclosure, there was technology available that provided multiple refrigerant detection sensors in an indoor unit to detect refrigerant leaks, and by appropriately using the multiple refrigerant detection sensors, it was possible to reduce the cumulative power supply time of each refrigerant detection sensor and suppress deterioration of the refrigerant detection sensors over time.

However, the inventors discovered a problem with conventional technology in that multiple refrigerant detection sensors are required, and therefore this technology is not capable of achieving a long service life when using a single refrigerant detection sensor to detect refrigerant leaks. In order to solve this problem, the inventors have come up with the subject matter of the present disclosure.
The present disclosure provides an air conditioner that can ensure safety while enabling a refrigerant detection sensor to be used for a long period of time.

Hereinafter, the embodiments will be described in detail with reference to the drawings. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or duplicate explanation of substantially the same configuration may be omitted. This is to avoid the following explanation becoming more redundant than necessary and to facilitate understanding by those skilled in the art.
It should be noted that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

(Embodiment 1)
Hereinafter, the first embodiment will be described with reference to FIGS. 1 to 8. FIG.
Fig. 1 is a side cross-sectional view of the air conditioning apparatus in embodiment 1. Fig. 2 is a plan view of the air conditioning apparatus in embodiment 1.

[1-1. Configuration of indoor unit]
1 and 2 , an air conditioner 1 in this embodiment includes an indoor unit 5. The indoor unit 5 includes a box-shaped housing 10. The housing 10 includes a top plate 11 and a bottom plate 12.
The left side of the housing 10 in Fig. 1 is an air blowing chamber 13, and the right side of the housing 10 in Fig. 1 is a heat exchanger chamber 14 that houses an indoor heat exchanger 20. The air blowing chamber 13 and the heat exchanger chamber 14 are separated by a partition wall 15.

A suction port 16 for taking in indoor air is provided at the rear of the blower chamber 13, and multiple scroll casings 31 (three in this embodiment) are provided inside the blower chamber 13, each of which houses a sirocco fan 30 as an indoor fan. An air outlet 17 is provided in the heat exchanger chamber 14 forward of the indoor heat exchanger 20.

The scroll casing 31 is provided with a fan opening 32 formed at both ends of the scroll casing 31, which draws in air flowing in from the suction port 16 by the rotation of the sirocco fan 30, and an air passage 33 which discharges the air drawn in from the fan opening 32 toward the heat exchanger chamber 14.
An electric motor 34 is provided between the scroll casings 31. The electric motor 34 is connected to a rotating shaft 35 of the sirocco fan 30, and drives the sirocco fan 30 to rotate.

The sirocco fan 30 is a centrifugal fan, and when the sirocco fan 30 is operating, air is drawn in through the suction port 16, and flowed into the inside of the scroll casing 31 from the fan opening 32 in the direction of the rotation shaft 35. The air is then blown out through the air passage 33 to the indoor heat exchanger 20, and the conditioned air that has been heat exchanged in the indoor heat exchanger 20 is discharged into the room through the air outlet 17.
A drain pan 21 is disposed below the indoor heat exchanger 20 housed in the heat exchanger chamber 14 in FIG.

2, in this embodiment, the heat exchanger chamber 14 is provided with a first partition plate 23 that separates the heat exchange region 22 of the indoor heat exchanger 20 from a pipe connection region on one end side of the indoor heat exchanger 20 to which refrigerant pipes 47, 48 (see FIG. 4) from the outdoor unit 40 (see FIG. 4) are connected. The pipe connection region is defined as a first region 24.
Further, a second partition plate 25 is provided in the heat exchanger chamber 14 to separate the heat exchange area 22 from a bend area on the other end side of the indoor heat exchanger 20 where the refrigerant piping of the indoor heat exchanger 20 is folded back. The bend area is defined as a second area 26.

A refrigerant duct 36 is provided in the heat exchanger chamber 14. The refrigerant duct 36 extends in the width direction of the heat exchanger chamber 14. An opening is provided at one end in the width direction of the refrigerant duct 36, and the refrigerant duct 36 is configured to communicate from the first partition plate 23 to the first region 24. In addition, an opening is provided at the other end in the width direction of the refrigerant duct 36, and the refrigerant duct 36 is configured to communicate from the second partition plate 25 to the second region 26.
Therefore, the first region 24 and the second region 26 are spatially connected through the coolant duct 36 .

A refrigerant detection sensor 50 for detecting refrigerant leakage is disposed in the first region 24 .
The refrigerant detection sensor 50 is capable of detecting refrigerant leakage in the first region 24. Furthermore, when refrigerant leakage occurs in the second region, the refrigerant detection sensor 50 is capable of detecting the refrigerant leakage based on the refrigerant that has flowed into the first region 24 through the refrigerant duct 36.
The refrigerant detection sensor 50 may be provided inside the refrigerant duct 36. The refrigerant detection sensor 50 may also be provided in the second region 26.

FIG. 3 is a diagram illustrating a refrigerant detection sensor 50 according to the first embodiment.
The refrigerant detection sensor 50 can be configured with any sensor capable of detecting the refrigerant, such as a semiconductor sensor, an infrared sensor, etc. In this embodiment, a case will be described in which the refrigerant detection sensor 50 is configured with a semiconductor sensor.
The refrigerant detection sensor 50 includes a circuit board 51 electrically connected to the control unit, a sensor element (detection unit) 52 provided on the circuit board 51, a heater 53 for heating the sensor element 52, and a cylindrical body (housing) 54 for accommodating the sensor element 52 and the heater 53. The refrigerant can enter the interior of the cylindrical body 54 through an opening 54a of the cylindrical body 54, thereby allowing the refrigerant to reach the sensor element 52.
A heat insulating material 55 is provided on the outer periphery of the cylindrical body 54. The heat insulating material 55 covers the cylindrical body 54. The heat insulating material 55 makes it easy to insulate the inside and outside of the cylindrical body 54. The heat insulating material 55 keeps the sensor element 52 warm. It is preferable that the heat insulating material 55 is provided on the outer periphery of the cylindrical body 54, but it may be omitted.

[1-2. Configuration of air conditioner]
Next, the configuration of the air conditioning device 1 will be described.
FIG. 4 is a refrigeration cycle diagram showing the configuration of the air conditioning apparatus 1 according to the first embodiment.
As shown in Fig. 4, the air conditioning apparatus 1 includes an outdoor unit 40 and an indoor unit 5. The outdoor unit 40 houses a compressor 41, a four-way valve 42 that switches the refrigerant flow path, an outdoor heat exchanger 43, an outdoor fan 44, and an outdoor throttling device 45, which are connected in sequence by refrigerant piping 46.

The indoor unit 5 accommodates an indoor heat exchanger 20, an indoor expansion device 27, and a sirocco fan 30, and the indoor heat exchanger 20 and the indoor expansion device 27 are connected via a refrigerant piping 28.
The compressor 41 of the outdoor unit 40 and the indoor heat exchanger 20 of the indoor unit 5 are connected by a liquid refrigerant pipe 47 and a gas refrigerant pipe 48 .
A refrigerant shutoff valve 49 is provided in the vicinity of the indoor unit 5 on each of the liquid refrigerant pipe 47 and the gas refrigerant pipe 48 .

[1-3. Control configuration]
Next, the control configuration of this embodiment will be described.
FIG. 5 is a block diagram showing a control configuration of this embodiment.
As shown in FIG. 5, the air conditioning apparatus 1 includes a control unit 60 .
The control unit 60 includes a processor that executes programs, such as a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit), and memories, such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and executes various processes through cooperation between hardware and software, such that the processor reads out the control programs stored in the memory and executes the processes.

The control unit 60 controls the compressor 41 of the outdoor unit 40, the outdoor expansion device 45, the outdoor fan 44, the sirocco fan 30 of the indoor unit 5, and the indoor expansion device 27 based on a control program.
The control unit 60 detects refrigerant leakage based on a detection signal from the refrigerant detection sensor 50 of the indoor unit 5. In addition, the control unit 60 controls the opening and closing of the refrigerant shutoff valve 49 and the indoor expansion device 27 based on the detection signal from the refrigerant detection sensor 50.

In this embodiment, the control unit 60 controls the operation of the refrigerant detection sensor 50. The control unit 60 controls the operation of the refrigerant detection sensor 50 by controlling whether or not electricity is applied to the refrigerant detection sensor 50.

In general, the refrigerant detection sensor 50 deteriorates more the longer the cumulative power-on time, which is the cumulative total time that the sensor is powered. Therefore, the control unit 60 controls the power-on time ratio of the refrigerant detection sensor 50 so that it is greater when refrigerant is flowing through the refrigerant piping 28 in the indoor unit 5 than when no refrigerant is flowing through the refrigerant piping 28 in the indoor unit 5. The power-on time ratio of the refrigerant detection sensor 50 is, for example, "power-on time of the refrigerant detection sensor 50 ÷ (power-on time of the refrigerant detection sensor 50 + power-off time of the refrigerant detection sensor 50)."

When refrigerant is flowing through the refrigerant piping 28 in the indoor unit 5, the refrigerant pressure in the indoor unit 5 increases, and the rate at which the concentration of leaking refrigerant increases if the refrigerant piping 28 is damaged increases. Therefore, by lengthening the power-on time ratio of the refrigerant detection sensor 50, leaking refrigerant can be detected quickly. On the other hand, when refrigerant is not flowing through the refrigerant piping 28 in the indoor unit 5, the refrigerant pressure in the indoor heat exchanger 20 decreases, and the rate at which the concentration of leaking refrigerant increases if the refrigerant piping 28 is damaged decreases. Therefore, when refrigerant is not flowing through the refrigerant piping 28 in the indoor unit 5, the control unit 60 reduces the power-on time ratio of the refrigerant detection sensor 50, thereby making it possible to detect refrigerant leakage while suppressing the cumulative power-on time of the refrigerant detection sensor 50.

Here, cases where refrigerant is flowing through the refrigerant piping 28 in the indoor unit 5 include, for example, cooling operation or heating operation. Also, cases where refrigerant is not flowing through the refrigerant piping 28 in the indoor unit 5 include, for example, air conditioning operation stopped, thermo-off operation, and fan operation. Thermo-off operation is an operation in which cooling or heating operation is not performed and the sirocco fan 30 is driven because the room temperature has reached the set temperature.

In addition, as a method for increasing the ratio of time that the refrigerant detection sensor 50 is energized, for example, there is continuous energization control, in which the refrigerant detection sensor 50 is energized continuously.In addition, as a method for decreasing the ratio of time that the refrigerant detection sensor 50 is energized, for example, there is intermittent energization control, in which the refrigerant detection sensor 50 is energized and de-energized repeatedly.

In this embodiment, the control unit 60 performs continuous current control while the compressor 41 is operating, and performs intermittent current control while the compressor 41 is stopped.

FIG. 6 is a timing chart of the operation of the compressor 41 and the energization control of the refrigerant detection sensor 50. In FIG.
In the intermittent current control of this embodiment, current is applied and not applied periodically. Specifically, when the control unit 60 starts the intermittent current control, it continuously applies current to the refrigerant detection sensor 50 for a predetermined current application time Ton. When the current application time Ton has elapsed, the control unit 60 stops applying current to the refrigerant detection sensor 50 for a predetermined non-current application time Toff. Furthermore, when the non-current application time Toff has elapsed, the control unit 60 continuously applies current to the refrigerant detection sensor 50 for the current application time Ton.
In this manner, while the compressor 41 is stopped (OFF), the control unit 60 executes intermittent energization control by periodically repeating energization for a current-on time Ton and de-energization for a de-energization time Toff in the cycle P. The cycle P is the sum of the current-on time Ton and the de-energization time Toff. In Fig. 6, a period C1 in which continuous energization control is executed and a period C2 in which intermittent energization control is executed are switched depending on whether the compressor 41 is operating (ON) or stopped (OFF).

FIG. 7 is a diagram illustrating the de-energization time Toff.
The de-energization time Toff is set based on various requirements.
Specifically, in the case where a refrigerant leak of a certain concentration or more occurs in the air conditioning device 1, the refrigerant leak must be detected within a predetermined specified time (first time) T1 after the refrigerant leak occurs. The specified time T1 is a time determined in advance by, for example, the Japan Refrigeration and Air Conditioning Industry Association (JRA) or the European Telecommunications Standards Association (EN).

The refrigerant detection sensor 50 also requires a warm-up before it can detect a refrigerant leak. In other words, the refrigerant detection sensor 50 does not become capable of detecting a refrigerant leak as soon as power is applied, and does not become capable of detecting a refrigerant leak until a warm-up time (second time) T2 has elapsed since power was applied. The warm-up time T2 is a value based on the specifications and characteristics of the refrigerant detection sensor 50.

As shown by arrows B1 to B3 in FIG. 7, the non-energized time Toff is set based on the difference T1-T2 between the preset specified time T1 during which the refrigerant leak must be detected after the refrigerant leaks, and the warm-up time T2 from when the refrigerant detection sensor 50 starts to be energized until the refrigerant detection sensor 50 can detect the refrigerant leak. In this embodiment, the non-energized time Toff is set to a value obtained by subtracting a predetermined margin Δ from the difference T1-T2. However, the non-energized time Toff may be set without subtracting the margin Δ from the difference T1-T2.

In this embodiment, the refrigerant detection sensor 50 is a semiconductor sensor. Therefore, the warm-up time T2 is the time required for the refrigerant detection sensor 50 to reach a predetermined detectable temperature (a temperature between 300°C and 400°C) from room temperature after starting to pass electricity through the refrigerant detection sensor 50.

The above-mentioned warm-up time T2 may be a time including a margin time in addition to the time required for the temperature to reach the detectable temperature from the normal temperature. The margin time is, for example, the time from when a refrigerant leak occurs until the refrigerant detection sensor 50 can detect the refrigerant leak (the leaked refrigerant can reach the sensor element 52). Specifically, when a refrigerant leak occurs in the second region 26, the margin time may be the time until the leaked refrigerant reaches the first region 24 through the refrigerant duct 36.
As a result, after the warm-up time T2 has elapsed, refrigerant leakage can be detected with high accuracy.

In addition, when the energization is stopped as in this embodiment, the heating of the sensor element 52 of the refrigerant detection sensor 50 is stopped, so the sensor element 52 is generally cooled. However, depending on the timing of restarting the energization, the sensor element 52 is heated from a temperature higher than room temperature, and the time required for warming up the refrigerant detection sensor 50 is shortened. In particular, when the refrigerant detection sensor 50 is covered with a heat insulating material 55 as in this embodiment, the warm-up time T2 is likely to be shortened due to the heat retention effect of the heat insulating material 55. Therefore, as shown by the arrow B2 in FIG. 7, the non-energization time Toff may be set based on a warm-up time T2 shorter than the warm-up time T2 at room temperature, and the intermittent energization control may be executed. This warm-up time T2 is set, for example, based on an experiment.
This makes it possible to reduce the cumulative energization time of the refrigerant detection sensor 50 .

Note that a shorter current flow time Ton makes it easier to reduce the cumulative current flow time.

In addition, the refrigerant detection sensor 50 is more likely to deteriorate as the accumulated energization time becomes longer, so the time required for warming up may become longer. Therefore, as shown by arrow B3 in FIG. 7, intermittent energization control may be performed based on the non-energization time Toff, which becomes shorter as the accumulated energization time becomes longer. In this case, for example, the control unit 60 stores a preset function for calculating the non-energization time Toff based on the accumulated energization time of the refrigerant detection sensor 50, and calculates the non-energization time Toff based on the accumulated energization time from the function. Then, the control unit 60 may stop energization for the calculated non-energization time Toff. In addition, the accumulated energization time of the refrigerant detection sensor 50 may be divided into stages in advance, and an optimal non-energization time Toff may be obtained according to the stage to which the accumulated energization time belongs. In this case, the relationship between the accumulated energization time and the non-energization time Toff can be stored by a lookup table.
The accumulated power supply time makes it possible to determine the life of the refrigerant detection sensor 50. For this reason, in the air conditioning apparatus 1, the accumulated power supply time is measured by the control unit 60.

[1-4. Operation]
The operation and function of the air conditioning apparatus 1 configured as above will now be described.
FIG. 8 is a flowchart showing the flow of processing by the control unit 60.
The control unit 60 starts the process in FIG. 8 when power is supplied to the air conditioning apparatus 1 .
8, the control unit 60 determines whether the compressor 41 is in operation (step ST11). In this embodiment, the compressor 41 is in operation means the period from when the compressor 41 starts operation to when the compressor 41 stops operation. In addition, the compressor 41 is not in operation, i.e., the compressor 41 is stopped, means the period from when the compressor 41 stops operation to when the compressor 41 starts operation.

When the control unit 60 determines that the compressor 41 is operating (step ST11: YES), it executes continuous current control for the refrigerant detection sensor 50 (step ST12). That is, the control unit 60 executes continuous current control from when the compressor 41 starts operating until when the compressor 41 stops operating.

When the control unit 60 determines that the compressor 41 is stopped (step ST11: NO), it executes intermittent current control for the refrigerant detection sensor 50 (step ST13). That is, the control unit 60 executes intermittent current control from when the compressor 41 stops operating until when the compressor 41 starts operating.

In general, when refrigerant is flowing through the refrigerant piping 28 in the indoor unit 5, such as when the compressor 41 is operating, the pressure in the refrigerant piping 28 in the indoor unit 5 is high. Therefore, if a refrigerant leak occurs, the concentration of the leaking refrigerant increases quickly. In this embodiment, when the compressor 41 is operating, current is continuously applied to the refrigerant detection sensor 50, making it easier to quickly detect a refrigerant leak.

In addition, when the compressor 41 is stopped, or when no refrigerant is flowing through the refrigerant piping 28 in the indoor unit 5, the pressure in the refrigerant piping 28 in the indoor unit 5 is low. For this reason, if a refrigerant leak occurs, the concentration of the leaking refrigerant increases slowly, which is known as a slow leak. Therefore, there is less need to quickly detect a refrigerant leak than when the compressor 41 is operating. Also, it often takes time for a refrigerant leak to be detectable. Therefore, in this embodiment, when the compressor 41 is stopped, intermittent current control is performed, making it possible to detect a refrigerant leak while suppressing the cumulative current flow time of the refrigerant detection sensor 50.

Specifically, as shown by arrow A1 in FIG. 6, when the compressor 41 stops (OFF), current is continuously applied to the refrigerant detection sensor 50 for a current application time Ton, and then current is stopped to the refrigerant detection sensor 50 for a non-current application time Toff. This is repeated until the compressor 41 starts operating.
In this case, for example, if a refrigerant leak occurs at time L1 immediately after the end of the power-on time Ton, the refrigerant detection sensor 50 is not operating, and therefore the leak cannot be detected immediately after the refrigerant leak. However, in this embodiment, the power-off time Toff is set based on the difference T1-T2 between the specified time T1 and the warm-up time T2, and therefore the warm-up of the refrigerant detection sensor 50 is completed at time L4 before the specified time T1 has elapsed from time L1. Therefore, at time L4, the refrigerant detection sensor 50 is able to detect the refrigerant leak that occurred at time L1, and therefore the refrigerant leak can be detected within the specified time T1 after the refrigerant leak occurs.

Similarly, if a refrigerant leak occurs at time L2 during the de-energized time Toff or at time L3 during the warm-up time T2, the leak cannot be detected immediately after the leak occurs. However, at time L4, the refrigerant detection sensor 50 has completed warm-up and is able to detect the refrigerant leak, so the refrigerant leak can be detected within the specified time T1 after the leak occurs.
Therefore, in this embodiment, while using a single refrigerant detection sensor 50, it is possible to ensure safety and enable the refrigerant detection sensor 50 to be used for a long period of time.

[1-5. Effects, etc.]
As described above, in this embodiment, in an air conditioning apparatus 1 including an outdoor unit 40 with a compressor 41, an indoor unit 5, a refrigerant detection sensor 50 provided in the indoor unit 5 for detecting refrigerant leakage, and a control unit 60 for controlling the operation of the refrigerant detection sensor 50, the control unit 60 controls the ratio of time that power is supplied to the refrigerant detection sensor 50.
As a result, in this embodiment, the refrigerant detection sensor 50 can be used for a long period of time while ensuring safety.

As in this embodiment, the control unit 60 executes intermittent power supply control to intermittently supply power to the refrigerant detection sensor 50, and the non-power supply time Toff of the refrigerant detection sensor 50 during the intermittent power supply control may be set within a specified time T1 during which it is necessary to detect the refrigerant leakage after the refrigerant leaks from the refrigerant piping 28.
This makes it possible to suppress the cumulative energization time of the refrigerant detection sensor 50 while allowing the refrigerant detection sensor 50 to be energized within the specified time T1. Therefore, in this embodiment, the refrigerant detection sensor 50 can be used for a long period of time while ensuring safety.

In the present embodiment, if the warm-up time T2 is the time from when current begins to flow to the refrigerant detection sensor 50 until the refrigerant detection sensor 50 is in a state where it can detect the refrigerant, the control unit 60 may control the non-energized time Toff of the refrigerant detection sensor 50 during intermittent current control to be within the time obtained by subtracting the warm-up time T2 from the specified time T1.
As a result, in the event of a refrigerant leak, even if the refrigerant detection sensor 50 returns from a non-energized state, the refrigerant leak can be detected within the specified time T1.

As in the present embodiment, the refrigerant detection sensor 50 may include a sensor element 52, a heater 53 for heating the sensor element 52, and a cylinder 54 that houses the sensor element 52 and the heater 53 and has an opening 54a through which the refrigerant flows in. The control unit 60 may also perform control so that the non-energization time Toff during the intermittent energization control is longer for a refrigerant detection sensor 50 in which a thermal insulator 55 is provided in the cylinder 54 than for a refrigerant detection sensor 50 in which a thermal insulator 55 is not provided in the cylinder 54.
This makes it easier to shorten the warm-up time T2 due to the heat retention effect of the insulating material 55. Therefore, even if the de-energized time Toff is extended, it is possible to detect a refrigerant leak within the specified time T1, and the integrated energized time of the refrigerant detection sensor 50 can be reduced.

As in the present embodiment, the control unit 60 may perform control such that the de-energization time Toff in the intermittent energization control becomes shorter as the integrated energization time of the refrigerant detection sensor 50 becomes longer.
As a result, even if the time required for the refrigerant detection sensor 50 to warm up increases with use, the de-energization time Toff is shortened, making it possible to detect a refrigerant leak within the specified time T1. This allows the refrigerant detection sensor 50 to be used for a long period of time while ensuring safety.

As in this embodiment, the control unit 60 may control the power supply time ratio to be greater when refrigerant is flowing through the refrigerant piping 28 in the indoor unit 5 than when no refrigerant is flowing through the refrigerant piping 28 in the indoor unit 5.
As a result, when refrigerant flows through the refrigerant pipe 28 in the indoor unit 5, the refrigerant pressure in the indoor unit 5 increases, and the rate of increase in the concentration of the leaking refrigerant increases if the refrigerant pipe 28 is damaged. Therefore, by increasing the current-on time ratio of the refrigerant detection sensor 50, the leaking refrigerant can be detected quickly. On the other hand, when refrigerant does not flow through the refrigerant pipe 28 in the indoor unit 5, the refrigerant pressure in the indoor heat exchanger 20 decreases, and the rate of increase in the concentration of the leaking refrigerant increases slowly if the refrigerant pipe 28 is damaged. Therefore, by decreasing the current-on time ratio of the refrigerant detection sensor 50, it is possible to detect a refrigerant leak while suppressing the cumulative current-on time of the refrigerant detection sensor 50. Therefore, the refrigerant detection sensor 50 can be used for a long period of time while ensuring safety.

As in this embodiment, when refrigerant is flowing through the refrigerant piping 28 in the indoor unit 5, the control unit 60 executes continuous current control to continuously energize the refrigerant detection sensor 50, and when no refrigerant is flowing through the refrigerant piping 28 of the indoor unit 5, the control unit 60 may execute intermittent current control to intermittently energize the refrigerant detection sensor 50.
This makes it possible to control, through simple control, so that the power supply time ratio is greater when refrigerant is flowing through the refrigerant piping 28 in the indoor unit 5 than when no refrigerant is flowing through the refrigerant piping 28 in the indoor unit 5. Furthermore, through the continuous power supply control, when refrigerant is flowing through the refrigerant piping 28 in the indoor unit 5, refrigerant leakage can be quickly detected.

As in this embodiment, the control unit 60 may execute the continuous current supply control when the compressor 41 is driven, and execute the intermittent current supply control when the compressor 41 is not driven.
This allows the power supply time ratio to be controlled to be greater when refrigerant is flowing through the refrigerant piping 28 in the indoor unit 5 in accordance with the driving and stopping of the compressor 41 than when no refrigerant is flowing through the refrigerant piping 28 in the indoor unit 5.

Other Embodiments
As described above, the first embodiment has been described as an example of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made. In addition, it is also possible to combine the components described in the first embodiment to create a new embodiment.
Therefore, other embodiments will be exemplified below.

In the first embodiment, the indoor unit 5 of the air conditioning device 1 is described as being provided with a single refrigerant detection sensor 50, but multiple refrigerant detection sensors may be provided. For example, the refrigerant detection sensor 50 may be provided in the first region 24, and a second refrigerant detection sensor may be provided in the second region 26. In this case, the refrigerant detection sensor 50 and the second refrigerant detection sensor may each be controlled to be energized while the compressor 41 is operating, and may be controlled to be intermittently energized while the compressor 41 is stopped.

In the intermittent current control of embodiment 1, when current is applied for a current application time Ton and current is not applied for a current non-application time Toff, a configuration has been described in which the current application time Ton is followed by current non-application time Toff when current is applied periodically in a cycle P. However, the current non-application time Toff may occur at any time within the cycle P. That is, for example, the current non-application time Toff may be set as shown by the arrow A2 in FIG. 6. Note that in the arrow A2 in FIG. 6, the total current application time within the cycle P is current application time Ton.

In the first embodiment, a configuration in which one indoor unit 5 is provided has been described, but the present invention is not limited to this, and a configuration in which multiple indoor units are provided may also be used. In this case, for example, when refrigerant is flowing through the refrigerant piping 28 of one of the two indoor units and refrigerant is not flowing through the refrigerant piping 28 of the other indoor unit, it is preferable that the control unit 60 executes communication current control for one indoor unit and executes intermittent current control for the other indoor unit.

In the first embodiment, a refrigerant shutoff valve 49 is provided to shut off the flow of refrigerant in the refrigerant piping 28, and the control unit 60 may execute a power supply stop control to stop the power supply to the refrigerant detection sensor 50 when the refrigerant shutoff valve 49 is closed due to a factor other than the detection of a refrigerant leak. In this case, for example, the control unit 60 starts to determine whether the refrigerant shutoff valve 49 is closed by supplying power to the air conditioning device 1. At this time, the control unit 60 repeats the determination of whether the refrigerant shutoff valve 49 is closed until it is determined that the refrigerant shutoff valve 49 is closed. Then, when the control unit 60 determines that the refrigerant shutoff valve 49 is closed, it determines whether a refrigerant leak has occurred. Then, when the control unit 60 determines that a refrigerant leak has not occurred, it executes a power supply stop control. In this way, the control unit 60 may execute a power supply stop control to stop the power supply to the refrigerant detection sensor 50 when the refrigerant shutoff valve 49 is closed due to a factor other than the detection of a refrigerant leak. When the refrigerant shutoff valve 49 is closed, even if the refrigerant piping 28 is damaged, the amount of leaked refrigerant is small, so safety can be ensured even if the power supply to the refrigerant detection sensor 50 is stopped. Circumstances in which the refrigerant shutoff valve 49 is closed due to factors other than refrigerant leakage detection are when no refrigerant flows through the refrigerant piping 28 in the indoor unit 5, such as when the air conditioning operation is stopped, when the fan is in operation, or when the thermostat is off.

In the air conditioning device 1 of the first embodiment, the control unit 60 has been described as controlling the refrigerant detection sensor 50 to be continuously energized as an example of increasing the ratio of energizing time to the refrigerant detection sensor 50. The present invention is not limited to this, and it is sufficient that the ratio of energizing time to the refrigerant detection sensor 50 is greater when refrigerant is flowing in the refrigerant piping 28 in the indoor unit 5 than when refrigerant is not flowing in the refrigerant piping 28 in the indoor unit 5. For example, when refrigerant is flowing in the refrigerant piping 28 in the indoor unit 5, the refrigerant detection sensor 50 may be basically energized and temporarily de-energized only for a short period of time (for example, 5 seconds). In addition, when refrigerant is flowing in the refrigerant piping 28 in the indoor unit 5, the control unit 60 may control the refrigerant detection sensor 50 to be intermittently energized, and control the de-energizing time Toff to be shorter when refrigerant is flowing in the indoor unit 5 than when refrigerant is flowing in the indoor unit 5.

In the first embodiment, the control unit 60 is configured to perform intermittent control operation when no refrigerant is flowing through the refrigerant piping 28 in the indoor unit 5, but the present invention is not limited to this. For example, the control unit 60 may perform intermittent control operation when the refrigerant pressure in the refrigerant piping 28 in the indoor unit 5 is relatively low even if refrigerant is flowing through the refrigerant piping 28 in the indoor unit 5, because the rate at which the concentration of the leaking refrigerant increases is relatively slow. In addition, a refrigerant pressure sensor may be used, for example, as a method for acquiring the refrigerant pressure in the refrigerant piping 28 in the indoor unit 5. In addition, it may be estimated that the refrigerant pressure in the refrigerant piping 28 in the indoor unit 5 is relatively low within a predetermined time from the start of operation of the compressor 41 after the compressor 41 is stopped.

In the air conditioning device 1 of the first embodiment, the control unit 60 has been described as being configured to execute intermittent current control while the compressor 41 is stopped. In the present invention, continuous current control may be executed when refrigerant is flowing in the refrigerant piping 28 in the indoor unit 5. For example, the control unit 60 may execute continuous current control for a predetermined time even after the compressor 41 is stopped, and execute intermittent current control after a predetermined time has elapsed since the compressor 41 was stopped. This is because refrigerant flows in the refrigerant piping 28 in the indoor unit 5 for a predetermined time even after the compressor 41 is stopped, and the refrigerant pressure in the refrigerant piping 28 is higher and the concentration of leaking refrigerant increases faster than when refrigerant is not flowing in the refrigerant piping 28.

In the air conditioning device 1 of embodiment 1, the control unit 60 is configured to execute continuous current control while the compressor 41 is in operation, but the present invention is not limited to this. For example, intermittent current control may be executed for a predetermined time after the compressor 41 starts operating, and continuous current control may be executed after a predetermined time has elapsed since the compressor 41 starts operating. This is because, within the predetermined time after the compressor 41 starts operating, the flow rate in the refrigerant piping 28 of the indoor unit 5 is low and the refrigerant pressure is relatively small, so the rate at which the concentration of leaking refrigerant increases is relatively slow.

In the first embodiment, the non-energization time Toff in the intermittent energization control is within the specified time T1 set in advance by the JRA. However, the present invention is not limited to this. For example, when the sirocco fan (indoor fan) 30 is driven, such as in a blowing operation, the non-energization time Toff in the intermittent energization control may be set to be equal to or longer than the specified time T1. If the sirocco fan 30 is driven and refrigerant leaks, the leaked refrigerant is diverted by the sirocco fan 30, and an increase in the concentration of the leaked refrigerant can be suppressed.

In the first embodiment, the control unit 60 executes continuous energization control to continuously energize the refrigerant detection sensor 50 when refrigerant is flowing in the refrigerant piping 28 in the indoor unit 5, and executes intermittent energization control to intermittently energize the refrigerant detection sensor 50 when no refrigerant is flowing in the refrigerant piping 28 of the indoor unit 5. However, instead of this, the control unit 60 may execute continuous energization control to continuously energize the refrigerant detection sensor 50 when refrigerant is flowing in the refrigerant piping 28 in the indoor unit 5, and execute energization stop control to stop energization of the refrigerant detection sensor 50 when no refrigerant is flowing in the refrigerant piping 28 of the indoor unit 5.
By performing the power supply stop control, the accumulated power supply time of the refrigerant detection sensor 50 can be effectively reduced.

Furthermore, in the first embodiment, the control unit 60 is configured to execute continuous current control when the compressor 41 is driven, and execute intermittent current control when the compressor 41 is not driven. However, instead of this, the control unit 60 may execute continuous current control when the compressor 41 is driven, and execute current stop control to stop current flow to the refrigerant detection sensor 50 when the compressor 41 is not driven.

In addition, in the first embodiment, the control unit 60 executes intermittent power supply control when the air conditioning operation is stopped, when the thermostat is off, or when the fan is operating. However, the control unit 60 may execute power supply stop control to stop the supply of power to the refrigerant detection sensor 50 when the air conditioning operation is stopped, when the thermostat is off, or when the fan is operating.

The indoor unit 5 of the air conditioning device 1 in the first embodiment is a so-called two-way ceiling cassette type indoor unit, but is not limited to this, and may be a four-way ceiling cassette type indoor unit, and the present disclosure may be applied to a refrigerant detection sensor provided in a four-way ceiling cassette type indoor unit.

The above-described embodiments are intended to illustrate the technology disclosed herein, and various modifications, substitutions, additions, omissions, etc. may be made within the scope of the claims or their equivalents.

This disclosure is particularly applicable to air conditioners that use refrigerant detection sensors.

Reference Signs List 1 Air conditioner 5 Indoor unit 28 Refrigerant piping 40 Outdoor unit 41 Compressor 50 Refrigerant detection sensor 52 Sensor element 53 Heater 54a Opening 54 Cylindrical body (housing)
55 Thermal insulation material 60 Control unit T1 Specified time T2 Warm-up time Toff De-energized time

Claims (9)

An air conditioning apparatus including an outdoor unit having a compressor, an indoor unit, a refrigerant detection sensor provided in the indoor unit for detecting a refrigerant leak, and a control unit for controlling the operation of the refrigerant detection sensor,
The control unit controls a current supply time ratio to the refrigerant detection sensor,
The control unit executes an intermittent energization control to energize the refrigerant detection sensor intermittently,
The de-energization time of the refrigerant detection sensor in the intermittent energization control is set to be within a time period required to detect the leakage of refrigerant after the leakage of refrigerant from the refrigerant piping.
Air conditioning equipment. If the warm-up time is the time from when the refrigerant detection sensor starts to be energized until the refrigerant detection sensor becomes capable of detecting the refrigerant,
The air-conditioning apparatus according to claim 1 , wherein the control unit controls a de-energization time of the refrigerant detection sensor during the intermittent energization control to be within a time obtained by subtracting the warm-up time from the necessary time . The refrigerant detection sensor includes a sensor element, a heater for heating the sensor element, and a housing for accommodating the sensor element and the heater and having an opening through which the refrigerant flows,
The air conditioning apparatus according to claim 2, wherein the control unit controls the non-energization time during the intermittent power supply control to be longer for the refrigerant detection sensor in which insulation is provided in the housing than for the refrigerant detection sensor in which insulation is not provided in the housing. The air conditioner according to claim 2 , wherein the control unit performs control such that the non-energized time in the intermittent energization control becomes shorter as an integrated energized time of the refrigerant detection sensor becomes longer. The air-conditioning apparatus according to claim 1 , wherein the control unit controls the power supply time ratio so that the power supply time ratio is greater when refrigerant is flowing through a refrigerant piping in the indoor unit than when refrigerant is not flowing through the refrigerant piping in the indoor unit. The air conditioning apparatus of claim 5, wherein the control unit executes continuous energization control to continuously energize the refrigerant detection sensor when refrigerant is flowing through the refrigerant piping in the indoor unit, and executes intermittent energization control to intermittently energize the refrigerant detection sensor or energization stop control to stop energization of the refrigerant detection sensor when refrigerant is not flowing through the refrigerant piping in the indoor unit . The air conditioning apparatus according to claim 6, wherein the control unit executes the continuous power supply control when the compressor is operating, and executes the intermittent power supply control or a power supply stop control that stops power supply to the refrigerant detection sensor when the compressor is not operating. The air conditioner according to claim 6 , wherein the control unit executes the intermittent power supply control or power supply stop control that stops power supply to the refrigerant detection sensor when an air conditioning operation is stopped, a thermo-off operation is in progress, or a fan operation is in progress. A refrigerant shutoff valve is provided to shut off the flow of the refrigerant.
The air-conditioning apparatus according to claim 6 , wherein the control unit executes the power supply stop control to stop power supply to the refrigerant detection sensor when the refrigerant shutoff valve is closed due to a factor other than detection of a refrigerant leak.