Air conditioner

Abstract

To provide an air conditioner that secures safety.SOLUTION: An air conditioner includes: a casing; a heat exchanger and a fan that are accommodated in the casing and in which a refrigerant flows; a sensor that detects a concentration of the refrigerant in the casing; and a control section that controls rotational frequency of the fan. The control section measures a concentration of the refrigerant that is a detection value obtained by the sensor, and when the concentration exceeds a first concentration threshold value, drives the fan and executes a first drive operation for stirring air in the casing for a predetermined time. After executing the first drive operation, the control section executes a second drive operation for intermittently driving the fan, continues the second drive operation when the concentration is raised during the execution of the second drive operation, and finishes the second drive operation to stop driving of the fan when the concentration is not raised.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to an air conditioning apparatus. [Background technology]

[0002] An air conditioner is composed of an indoor unit and an outdoor unit. The indoor unit and the outdoor unit are connected by refrigerant piping, through which a refrigerant circulates. Each indoor unit and outdoor unit is provided with a blower, which is driven to generate airflow and exchange heat between the surrounding air and the refrigerant. For example, a widely known air conditioner has a refrigerant circuit equipped with a heat exchanger that exchanges heat between the refrigerant and the air, a blower fan that agitates the air in a space isolated from the refrigerant circuit, a sensor that detects refrigerant leakage in the space, and a controller that controls the operation of the blower fan.

[0003] Conventionally, there is a technology in which a sensor is installed in the indoor unit to detect the concentration of refrigerant in the air around the indoor unit, and when refrigerant leaks from the indoor unit, the indoor unit's blower fan is driven to agitate the indoor air containing the leaked refrigerant. This prevents the occurrence of a region in which the refrigerant concentration in the indoor air falls within the flammable concentration range (hereinafter referred to as the flammable concentration region).

[0004] In recent years, refrigerants with low GWP (Global Warming Potential) have been increasingly adopted to prevent global warming, such as R32 refrigerant or refrigerants with lower upper and lower limits of the flammable concentration range than R32 refrigerant. Examples of such refrigerants include R290, R600a, R1270, R717, R1132E, R152a, and R1234yf. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-166680 [Patent Document 2] International Publication No. 2016 / 153021 Summary of the Invention [Problem to be solved by the invention]

[0006] In conventional air conditioners, the blower fan stops operating when the refrigerant concentration in the indoor space falls below the lower limit of the flammable concentration range. However, even if the blower fan stops operating when the concentration falls below the lower limit of the flammable concentration range, if the refrigerant leak continues, the concentration may rise again, potentially creating a flammable concentration range.

[0007] Furthermore, when using refrigerants such as the hydrocarbon refrigerant R290 or the fluorine refrigerant R1234yf, the upper and lower limits of the flammable concentration range are lower than those of the R32 refrigerant, so even a small amount of leaked refrigerant is more likely to remain within the flammable concentration range, increasing the risk of ignition within the indoor space.

[0008] Therefore, there is a demand for an air conditioning device that can ensure safety by reducing the risk of ignition within the space.

[0009] In one aspect, an object is to provide an air conditioner that ensures safety. [Means for solving the problem]

[0010] An air conditioning apparatus according to one embodiment includes a housing, a heat exchanger and a fan through which a refrigerant contained in the housing flows, a sensor for detecting the concentration of the refrigerant within the housing, and a control unit for controlling the rotation speed of the fan. The control unit measures the concentration of the refrigerant detected by the sensor, and when the concentration exceeds a first concentration threshold, executes a first drive operation for a predetermined time in which the control unit drives the fan to agitate the air within the housing. After executing the first drive operation, the control unit executes a second drive operation in which the fan is intermittently driven, and if the concentration increases during the second drive operation, continues the second drive operation, and if the concentration does not increase, ends the second drive operation and stops driving the fan. [Effects of the Invention]

[0011] According to one aspect, safety can be ensured. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is an explanatory diagram showing an example of the configuration of an air conditioning apparatus according to this embodiment. [Figure 2] FIG. 2 is a block diagram illustrating an example of the configuration of the first control unit according to the first embodiment. [Figure 3] FIG. 3 is a block diagram illustrating an example of the configuration of the second control unit according to the first embodiment. [Figure 4] FIG. 4 is an explanatory diagram showing an example of the transition of the refrigerant concentration during the second driving operation. [Figure 5] FIG. 5 is a flowchart illustrating an example of a processing operation of the first control unit related to the outdoor fan control process according to the first embodiment. [Figure 6] FIG. 6 is a flowchart illustrating an example of a processing operation of the second control unit related to the indoor fan control process according to the first embodiment. [Figure 7] FIG. 7 is a block diagram illustrating an example of the configuration of the first control unit according to the second embodiment. [Figure 8] FIG. 8 is a block diagram illustrating an example of the configuration of the second control unit according to the second embodiment. [Figure 9] FIG. 9 is an explanatory diagram showing an example of the transition of the refrigerant concentration during the second driving operation. [Figure 10] FIG. 10 is a flowchart illustrating an example of a processing operation of the first control unit related to the outdoor fan control process of the second embodiment. [Figure 11] FIG. 11 is a block diagram illustrating an example of the configuration of the first control unit according to the third embodiment. [Figure 12] FIG. 12 is a block diagram illustrating an example of the configuration of the second control unit according to the third embodiment. [Figure 13] FIG. 13 is a flowchart illustrating an example of a processing operation of the first control unit related to the outdoor fan control processing of the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of an air conditioning apparatus disclosed in the present application will be described in detail with reference to the drawings. Note that the present invention is not limited to this embodiment. Furthermore, the following examples may be combined as appropriate within the scope of not causing any contradiction. [Example]

[0014] Fig. 1 is an explanatory diagram showing an example of the configuration of an air conditioner 1 of this embodiment. The air conditioner 1 shown in Fig. 1 has an outdoor unit 10 and an indoor unit 20. The outdoor unit 10 is, for example, a device installed outdoors. The indoor unit 20 is, for example, a device installed in an indoor space.

[0015] The outdoor unit 10 has a first casing 10A, a compressor 11, a four-way valve 12, an outdoor heat exchanger 13, an outdoor expansion valve 14, an outdoor fan 15, a first sensor 31A, and a first control unit 16. The first casing 10A houses the compressor 11, the four-way valve 12, the outdoor heat exchanger 13, the outdoor expansion valve 14, the outdoor fan 15, the first sensor 31A, and the first control unit 16. The indoor unit 20 has a second casing 20A, an indoor heat exchanger 21, an indoor fan 23, a second sensor 31B, and a second control unit 24. The second casing 20A houses the indoor heat exchanger 21, the indoor fan 23, the second sensor 31B, and the second control unit 24.

[0016] The outdoor unit 10 and the indoor unit 20 are connected to each other so that a refrigerant circulates through a liquid pipe 32 and a gas pipe 33. The air conditioner 1 has a refrigerant circuit. The refrigerant circuit has a compressor 11, a four-way valve 12, an outdoor heat exchanger 13, an outdoor expansion valve 14, an indoor heat exchanger 21, the liquid pipe 32, and the gas pipe 33.

[0017] Compressor 11 is a variable capacity compressor whose operating capacity can be varied by being driven by a motor (not shown) whose rotation speed is controlled by an inverter. Four-way valve 12 has a first port a, a second port b, a third port c, and a fourth port d. First port a is connected to a discharge port of compressor 11 via refrigerant piping 17a. Second port b is connected to one refrigerant inlet / outlet of outdoor heat exchanger 13 via refrigerant piping 17b. Third port c is connected to a suction port of compressor 11 via refrigerant piping 17c. Fourth port d is connected to shut-off valve 18, which is connected to gas pipe 33 via refrigerant piping 17d.

[0018] The outdoor heat exchanger 13 is a heat exchanger that exchanges heat between outside air taken into the outdoor unit 10 by the outdoor fan 15 and refrigerant flowing through a refrigerant pipe. One refrigerant inlet / outlet of the outdoor heat exchanger 13 is connected to the second port b of the four-way valve 12 by a refrigerant pipe 17b. The other refrigerant inlet / outlet of the outdoor heat exchanger 13 is connected to a stop valve 19 by a refrigerant pipe 17e. An outdoor expansion valve 14 is provided in the refrigerant pipe 17e that connects the other refrigerant inlet / outlet and the stop valve 19.

[0019] The outdoor fan 15 is driven by a motor (not shown) to take in outside air into the outdoor unit 10 and generate an air flow for discharging the outside air that has exchanged heat with the refrigerant in the outdoor heat exchanger 13 to the outside of the outdoor unit 10. The outdoor fan 15 also generates an air flow within the first housing 10A, and therefore can agitate air containing refrigerant that has leaked within the first housing 10A.

[0020] The first control unit 16 is a control unit that executes control of the start, stop, and rotation speed of the compressor 11, switching control of the four-way valve 12, control of the opening degree of the outdoor expansion valve 14, and drive control of the outdoor fan 15. Furthermore, the first control unit 16 receives a start request or stop request from the air conditioner 1 and controls at least the start and stop of the compressor 11.

[0021] The indoor heat exchanger 21 is a heat exchanger that exchanges heat between the indoor air taken into the indoor unit 20 by the indoor fan 23 and the refrigerant flowing through the refrigerant piping. One refrigerant inlet and outlet of the indoor heat exchanger 21 is connected to refrigerant piping 28a, which is connected to connection port 26. The other refrigerant inlet and outlet of the indoor heat exchanger 21 is connected to refrigerant piping 28b, which is connected to connection port 27. A liquid pipe 32 connects the shut-off valve 19 of the outdoor unit 10 to the connection port 27 of the indoor unit 20, and a gas pipe 33 connects the shut-off valve 18 of the outdoor unit 10 to the connection port 26 of the indoor unit 20.

[0022] The indoor fan 23 is driven by a motor (not shown) to draw in outside air into the indoor unit 20 and generate an air flow for discharging the outside air that has exchanged heat with the refrigerant in the indoor heat exchanger 21 to the outside of the indoor unit 20. The indoor fan 23 also generates an air flow within the second housing 20A, and therefore can agitate air containing refrigerant that has leaked within the second housing 20A.

[0023] The outdoor unit 10 has, for example, a first sensor 31A and a first control unit 16 disposed in a first housing 10A. The first sensor 31A is an infrared sensor that can detect the concentration of refrigerant contained in the air. The first sensor 31A measures the concentration of refrigerant leaking into the first housing 10A of the outdoor unit 10 and outputs the measurement result of the refrigerant concentration in the first housing 10A to the first control unit 16.

[0024] The indoor unit 20 has, for example, a second sensor 31B and a second control unit 24 disposed in the second housing 20A. The second sensor 31B is an infrared sensor that can detect the concentration of refrigerant contained in the air. The second sensor 31B measures the concentration of refrigerant leaking into the second housing 20A of the indoor unit 20 and outputs the measurement result of the refrigerant concentration in the second housing 20A to the second control unit 24.

[0025] FIG. 2 is a block diagram showing an example of the configuration of the first control unit 16 according to the first embodiment. The first control unit 16 shown in FIG. 2 includes a first communication unit 41, a first memory 43, and a first control unit 44. The first communication unit 41A is a communication unit on the outdoor unit 10 side that communicates with the second control unit 24. The first memory 43 stores various information. The first memory 43 includes, for example, a first threshold memory 43A that stores various thresholds, a first concentration memory 43B that temporarily stores the refrigerant concentration in the first casing 10A, which is the measurement result, and a first drive operation table 43C that pre-stores the operation details for each drive operation of the outdoor fan 15 in the first casing 10A. The first control unit 44 controls the entire first control unit 16.

[0026] The first threshold memory 43A stores a first concentration threshold in advance. The first concentration threshold is a threshold for determining whether a refrigerant leak has occurred in the first housing 10A, and is set to a value within a range from the lower limit of the concentration measurable by the sensor to a concentration of ¼ of the LFL (Long-Term Flux Level), which will be described later.

[0027] The refrigerant used in the air conditioner 1 is a flammable refrigerant whose lower limit of the flammable concentration range (explosive range) is less than 13.3 vol%. Examples of such refrigerants include R290, R600a, R1270, R717, R1132E, R152a, and R1234yf. The flammable concentration range (explosive range) is the concentration range in which the refrigerant can burn. The UFL (Upper Flammability Limit) is the upper limit of the flammable concentration range of the refrigerant. The LFL (Lower Flammability Limit) is the lower limit of the flammable concentration range of the refrigerant. Note that the flammable concentration range differs depending on the type of refrigerant. For example, the width of the flammable concentration range (UFL-LFL) of R290 and R1234yf is smaller than that of R32. However, since the concentration gradually changes toward 0% during stirring, the rate of decrease per unit time decreases as the concentration approaches 0%. As a result, refrigerants such as R290 and R1234yf, which have a low flammable concentration range, will remain within the flammable concentration range for a longer period of time, which could result in their concentrations remaining within the flammable concentration range and extending the time that the flammable concentration region exists in the space.

[0028] The first drive operation table 43C is a table in which operation details for each drive operation of the outdoor fan 15 in the first casing 10A are stored. The drive operations include a first drive operation and a second drive operation. The first drive operation is an operation in which the outdoor fan 15 is driven to agitate the air in the first casing 10A when the refrigerant concentration in the first casing 10A exceeds a first concentration threshold. The second drive operation is an operation in which the outdoor fan 15 is intermittently driven after the first drive operation is executed. Since the second drive operation is an operation in which the outdoor fan 15 is intermittently driven, for example, the outdoor fan 15 is driven continuously for a first predetermined time (e.g., five minutes), and after the first predetermined time, the outdoor fan 15 is stopped from being driven for a second predetermined time. The second predetermined time is set in advance as the time when the air flow in the first housing 10A generated by driving the outdoor fan 15 stops and the first sensor 31A can detect the concentration without being affected by the air flow. The first predetermined time and the second predetermined time can be set or changed as appropriate. Furthermore, the rotation speed of the outdoor fan 15 in the first drive operation and the second drive operation is set to be approximately the same, but this is not limited to this and can be changed as appropriate.

[0029] The first control unit 44 determines whether the refrigerant concentration in the first casing 10A has exceeded a first concentration threshold. When the refrigerant concentration in the first casing 10A has exceeded the first concentration threshold, the first control unit 44 performs a first drive operation of the outdoor fan 15. After performing the first drive operation, the first control unit 44 performs a second drive operation in which the outdoor fan 15 is intermittently driven.

[0030] During a second predetermined time while the second drive operation is being performed, the first control unit 44 measures the refrigerant concentration in the first casing 10A multiple times using the first sensor 31A. Based on the change in the refrigerant concentration over time obtained through the measurement, the first control unit 44 determines whether the refrigerant concentration in the first casing 10A has increased during the second predetermined time. If the first control unit 44 determines that the refrigerant concentration in the first casing 10A has increased, it continues the second drive operation. On the other hand, if the first control unit 44 determines that the refrigerant concentration has not increased, it ends the second drive operation and stops driving the outdoor fan 15.

[0031] FIG. 3 is a block diagram showing an example of the configuration of the second control unit 24 of the first embodiment. The second control unit 24 shown in FIG. 2 includes a second communication unit 51, a second memory 53, and a second control unit 54. The second communication unit 51 is a communication unit on the indoor unit 20 side that communicates with the first control unit 16. The second memory 53 stores various information. The second memory 53 includes, for example, a second threshold memory 53A that stores various thresholds, a second concentration memory 53B that temporarily stores the refrigerant concentration in the second casing 20A, which is the measurement result, and a second drive operation table 53C that pre-stores the operation details for each drive operation of the indoor fan 23 in the second casing 20A. The second control unit 54 controls the entire second control unit 24.

[0032] The second threshold memory 53A stores a first concentration threshold in advance. The first concentration threshold is a threshold for determining whether a refrigerant leak has occurred in the second housing 20A, and is set to a value within a range from the lower limit of the concentration measurable by the sensor to a concentration of ¼ of the LFL (Long-Term Flux Level), which will be described later.

[0033] The second drive operation table 53C is a table in which operation details for each drive operation of the indoor fan 23 in the second casing 20A are stored. The drive operations include a first drive operation and a second drive operation. The first drive operation is an operation in which the indoor fan 23 is driven to agitate the air in the second casing 20A when the refrigerant concentration in the second casing 20A exceeds a first concentration threshold. The second drive operation is an operation in which the indoor fan 23 is intermittently driven after the first drive operation is performed. Since the second drive operation is an operation in which the indoor fan 23 is intermittently driven, for example, the indoor fan 23 is driven continuously for a first predetermined time, and after the first predetermined time, the drive of the indoor fan 23 is stopped continuously for a second predetermined time. The first predetermined time and the second predetermined time can be changed as appropriate. Furthermore, the rotation speed of the indoor fan 23 in the first drive operation and the second drive operation is set to be approximately the same rotation speed, but is not limited to this and can be changed as appropriate. Note that although the first drive operation and the second drive operation are given the same names as the first drive operation and the second drive operation stored in the first drive operation table 43C of the first control unit 16, different values ​​are set for the rotation speed of the fan and the on / off time due to differences in the airflow rates of the outdoor fan 15 and the indoor fan 23, differences in the volumes of the first housing 10A and the second housing 20A, etc.

[0034] The second control unit 54 determines whether the refrigerant concentration in the second casing 20A has exceeded a first concentration threshold. When the second control unit 54 determines that the refrigerant concentration in the second casing 20A has exceeded the first concentration threshold, the second control unit 54 performs a first drive operation of the indoor fan 23. After performing the first drive operation, the second control unit 54 performs a second drive operation in which the indoor fan 23 is intermittently driven.

[0035] The second control unit 54 measures the refrigerant concentration in the second casing 20A multiple times using the second sensor 31B during a second predetermined time while the second drive operation is being performed. The second control unit 54 determines whether the refrigerant concentration in the second casing 20A has increased during the second predetermined time based on the change in the refrigerant concentration over time obtained through the measurement. If the second control unit 54 determines that the refrigerant concentration in the second casing 20A has increased, it continues the second drive operation. On the other hand, if it determines that the refrigerant concentration has not increased, it ends the second drive operation and stops driving the indoor fan 23.

[0036] 4 is an explanatory diagram showing an example of changes in refrigerant concentration during the second drive operation. For ease of explanation, the change in refrigerant concentration during the second drive operation when the first control unit 44 controls the outdoor fan 15 is shown as an example, but the change in refrigerant concentration during the second drive operation when the second control unit 54 controls the indoor fan 23 is similar, so a description thereof will be omitted.

[0037] 4, the first control unit 44 starts the second drive operation after executing the first drive operation. As a result, the outdoor fan 15 continues to be driven for a first predetermined time as the second drive operation, and the refrigerant concentration in the first casing 10A gradually decreases by agitating the air in the first casing 10A. Next, the first control unit 44 pauses the drive of the outdoor fan 15 for a second predetermined time after the first predetermined time of the second drive operation. Then, the first control unit 44 measures the refrigerant concentration multiple times within the second predetermined time and determines whether the refrigerant concentration in the first casing 10A has increased based on the change in the measurement results over time.

[0038] If the refrigerant concentration increases within the second predetermined time, the first control unit 44 determines that refrigerant has leaked into the first housing 10A and continues the second drive operation.The first control unit 44 then continues drive operation of the outdoor fan 15 for a first predetermined time as the second drive operation, and pauses drive of the outdoor fan 15 for a second predetermined time after the first predetermined time of the second drive operation has elapsed.

[0039] Then, first control unit 44 measures the refrigerant concentration multiple times within a second predetermined time period, and determines whether the refrigerant concentration within first casing 10A has increased based on the change over time of the measurement results. If first control unit 44 determines that the refrigerant concentration within the second predetermined time period has not increased, it determines that no refrigerant is leaking into first casing 10A, and ends the second driving operation.

[0040] In other words, after the first drive operation is performed, the first control unit 44 does not immediately stop the drive of the outdoor fan 15, but instead performs the second drive operation, continues the second drive operation if the refrigerant concentration increases within a second predetermined time, and ends the second drive operation if the refrigerant concentration does not increase within the second predetermined time.

[0041] Fig. 5 is a flowchart showing an example of the processing operation of the first control unit 16 related to the outdoor fan control process of Example 1. In Fig. 5, the first control unit 44 in the first control unit 16 determines whether the refrigerant concentration in the first casing 10A measured by the first sensor 31A exceeds a first concentration threshold (step S11). If the refrigerant concentration in the first casing 10A exceeds the first concentration threshold (step S11: Yes), the first control unit 44 determines that a refrigerant leak has occurred in the first casing 10A, and starts a first driving operation of the outdoor fan 15 (step S12).

[0042] After performing the first driving operation for a first predetermined time, the first control unit 44 starts the second driving operation of the outdoor fan 15 (step S16). The first predetermined time is set in advance through testing or the like to be a time that is sufficient to agitate the leaked refrigerant in the first casing 10A.

[0043] The first control unit 44 measures the refrigerant concentration in the first casing 10A multiple times during the second predetermined time period during which the second drive operation is stopped (step S17). The first control unit 44 stores the multiple refrigerant concentrations measured during the second predetermined time period in the first concentration memory 43B in chronological order. The first control unit 44 then determines the change over time in the refrigerant concentration measured during the second predetermined time period. Based on the change over time in the refrigerant concentration measured during the second predetermined time period, the first control unit 44 determines whether the refrigerant concentration in the first casing 10A during the second predetermined time period has increased (step S18). If the refrigerant concentration in the first casing 10A has not increased (step S18: No), the first control unit 44 stops the second drive operation of the outdoor fan 15 (step S19) and ends the processing operation shown in FIG. 5.

[0044] If the refrigerant concentration in the first casing 10A does not exceed the first concentration threshold (step S11: No), the first control unit 44 determines that a refrigerant leak has not occurred in the first casing 10A, and terminates the processing operation shown in FIG. 5.

[0045] If the refrigerant concentration in the first casing 10A has increased (step S18: Yes), the first control unit 44 determines that refrigerant leakage in the first casing 10A is continuing, and returns to the processing of step S16 in which the second driving operation of the outdoor fan 15 is resumed. As a result, the driving of the outdoor fan 15 continues.

[0046] Fig. 6 is a flowchart showing an example of the processing operation of the second control unit 24 related to the indoor fan control process of Example 1. In Fig. 6, the second control unit 54 in the second control unit 24 determines whether the refrigerant concentration in the second casing 20A measured via the second sensor 31B exceeds a first concentration threshold (step S11A). If the refrigerant concentration in the second casing 20A exceeds the first concentration threshold (step S11A: Yes), the second control unit 54 determines that a refrigerant leak has occurred in the second casing 20A, and starts a first driving operation of the indoor fan 23 (step S12A).

[0047] After performing the first driving operation for a first predetermined time, the second control unit 54 starts the second driving operation of the indoor fan 23 (step S16A). The first predetermined time is set in advance through testing or the like to be a time that is sufficient to agitate the leaked refrigerant in the second casing 20A.

[0048] The second control unit 54 measures the refrigerant concentration in the second casing 20A multiple times during a second predetermined time period during which the second drive operation is stopped (step S17A). The second control unit 54 stores the multiple refrigerant concentrations measured during the second predetermined time period in chronological order in the second concentration memory 53B. The second control unit 54 then determines the change over time in the refrigerant concentration measured during the second predetermined time period. The second control unit 54 determines whether the refrigerant concentration in the second casing 20A during the second predetermined time period has increased based on the change over time in the refrigerant concentration measured during the second predetermined time period (step S18A). If the refrigerant concentration in the second casing 20A has not increased (step S18A: No), the second control unit 54 stops the second drive operation of the indoor fan 23 (step S19A) and ends the processing operation shown in FIG. 6.

[0049] If the refrigerant concentration in the second casing 20A does not exceed the first concentration threshold (step S11A: No), the second control unit 54 determines that a refrigerant leak has not occurred in the second casing 20A, and terminates the processing operation shown in FIG. 6.

[0050] If the refrigerant concentration in the second casing 20A has increased (step S18A: Yes), the second control unit 54 determines that refrigerant leakage in the second casing 20A is continuing, and returns to the processing of step S16A in which the second driving operation of the indoor fan 23 is resumed. As a result, the driving of the indoor fan 23 continues.

[0051] The first control unit 16 in the air conditioning apparatus 1 of the first embodiment starts the second drive operation after the first drive operation is performed, and determines whether the concentration has increased during the second drive operation. The first control unit 16 continues the second drive operation if the refrigerant concentration in the first housing 10A has increased, and ends the second drive operation if the concentration has not increased. As a result, the risk of ignition within the space due to a re-increase in concentration caused by continued refrigerant leakage after the first drive operation is performed can be reduced, ensuring safety.

[0052] When the refrigerant concentration in first housing 10A increases within a second predetermined time, first control unit 16 starts a drive operation that continues for a first predetermined time, and then executes a second drive operation that stops the drive operation for a second predetermined time after the first predetermined time has elapsed. As a result, it is possible to ensure safety by suppressing the risk of ignition within the space due to a re-increase in concentration caused by continued refrigerant leakage after the first drive operation has been executed.

[0053] The second control unit 24 starts the second drive operation after the first drive operation is performed, and determines whether the concentration has increased during the second drive operation. The second control unit 24 continues the second drive operation if the refrigerant concentration in the second housing 20A has increased, and ends the second drive operation if the concentration has not increased. As a result, the risk of ignition within the space due to a re-increase in concentration caused by continued refrigerant leakage after the first drive operation is performed can be reduced, ensuring safety.

[0054] If the refrigerant concentration in second housing 20A increases within a second predetermined time, second control unit 24 starts a drive operation that continues for a first predetermined time, and then executes a second drive operation that stops the drive operation for a second predetermined time after the first predetermined time has elapsed. As a result, the risk of ignition within the space due to a re-increase in concentration caused by continued refrigerant leakage after the first drive operation is executed can be reduced, ensuring safety.

[0055] For ease of explanation, the example has been given in which the first control unit 44 in the first control unit 16 of the outdoor unit 10 is used to determine the threshold value of the refrigerant concentration in the first casing 10A and to determine whether the refrigerant concentration has increased within the second predetermined time. Also, the example has been given in which the second control unit 54 in the second control unit 24 of the indoor unit 20 is used to determine the threshold value of the refrigerant concentration in the second casing 20A and to determine whether the refrigerant concentration has increased within the second predetermined time. However, the threshold value of the refrigerant concentration in the first casing 10A and the second casing 20A and the determination whether the refrigerant concentration has increased within the second predetermined time may be determined by either the first control unit 16 or the second control unit 24, and this can be changed as appropriate.

[0056] For example, the second control unit 24 acquires the refrigerant concentration in the first casing 10A from the first control unit 16, and extracts the type of drive operation of the outdoor fan 15 from the first drive operation table 43C based on the refrigerant concentration in the first casing 10A. The second control unit 24 then transmits the extracted type of drive operation of the outdoor fan 15 to the first control unit 16. The first control unit 16 may then perform the drive operation of the outdoor fan 15 using the type of drive operation of the outdoor fan 15 acquired from the second control unit 24.

[0057] Furthermore, for example, the first control unit 16 acquires the refrigerant concentration in the second casing 20A from the second control unit 24, and extracts the type of drive operation of the indoor fan 23 from the second drive operation table 53C based on the refrigerant concentration in the second casing 20A. Then, the first control unit 16 transmits the extracted type of drive operation of the indoor fan 23 to the second control unit 24. Then, the second control unit 24 may perform the drive operation of the indoor fan 23 using the type of drive operation of the indoor fan 23 acquired from the first control unit 16.

[0058] In the first control unit 16 of the first embodiment, for example, the second drive operation is continued when the refrigerant concentration in the first casing 10A of the outdoor unit 10 increases within the second predetermined time. However, the first drive operation may be executed instead of the second drive operation, and this can be modified as appropriate. As a result, when the refrigerant concentration in the first casing 10A increases, the first drive operation is resumed with the stirring operation instead of continuing the second drive operation. In other words, even if refrigerant leakage from the refrigerant circuit continues during the second drive operation, the refrigerant is reliably stirred, thereby reducing the risk of ignition in the first casing 10A and ensuring safety.

[0059] Similarly, while the second control unit 24 has been described as continuing the second drive operation when the refrigerant concentration in the second casing 20A of the indoor unit 20 increases within a second predetermined time, the second control unit 24 may instead execute the first drive operation. As a result, when the refrigerant concentration in the second casing 20A increases, the second drive operation is resumed with the stirring operation of the first drive operation instead of continuing the second drive operation. In other words, even if refrigerant leakage from the refrigerant circuit continues during the second drive operation, the refrigerant is reliably stirred, thereby reducing the risk of ignition in the second casing 20A and ensuring safety.

[0060] Furthermore, in the air conditioning apparatus 1 of Example 1, for example, a case has been illustrated in which the second drive operation of the outdoor fan 15 is stopped when the refrigerant concentration in the first casing 10A of the outdoor unit 10 has not increased within a second predetermined time. However, the present invention is not limited to this, and an embodiment thereof will be described below as Example 2. Note that the same components as those in the air conditioning apparatus 1 of Example 1 are given the same reference numerals, and descriptions of the overlapping components and operations will be omitted. [Example]

[0061] Fig. 7 is a block diagram showing an example of the configuration of a first control unit 16A of Example 2. The first control unit 16A of Example 2 shown in Fig. 7 differs from the first control unit 16 of Example 1 in that, when the refrigerant concentration does not increase within a second predetermined time during the second drive operation of the outdoor fan 15, the second drive operation is not immediately stopped, but the number of times it is determined that the refrigerant concentration has not increased is counted, and the second drive operation is continued until the count value reaches a predetermined count value.

[0062] The first memory 43 has a first count memory 43D in addition to a first threshold memory 43A1, a first concentration memory 43B, and a first drive operation table 43C. In addition to the first concentration threshold, the first threshold memory 43A1 stores a predetermined count value as a threshold for determining whether the refrigerant concentration in the first casing 10A continues to be below the LFL of the flammable concentration range. This predetermined count value is set to, for example, 2 to 3 times.

[0063] The first control unit 44A measures the refrigerant concentration within a second predetermined time during the second driving operation of the outdoor fan 15 via the first sensor 31A. The first control unit 44A determines whether the refrigerant concentration within the second predetermined time has increased. If the refrigerant concentration within the second predetermined time has not increased, the first control unit 44A increments the count value by 1 and stores the count value in the first count memory 43D. The first control unit 44A determines whether the count value has reached a predetermined count value stored in the first threshold memory 43A1.

[0064] When the count value reaches and is equal to the predetermined count value, the first control unit 44A ends the second drive operation of the outdoor fan 15. When the count value does not reach and is not equal to the predetermined count value, the first control unit 44A continues the second drive operation of the outdoor fan 15.

[0065] 8 is a block diagram illustrating an example of the configuration of a second control unit 24A according to a second embodiment. The second control unit 24A according to the second embodiment illustrated in FIG. 8 differs from the second control unit 24 according to the first embodiment in that, instead of immediately stopping the second drive operation when the refrigerant concentration has not increased within a second predetermined time during the second drive operation of the indoor fan 23, the second control unit 24A counts the number of times that it is determined that the refrigerant concentration has not increased and continues the second drive operation until the count value reaches a predetermined count value. Note that although the predetermined count value is given the same name as the predetermined count value stored in the first threshold memory 43A1 of the first control unit 16, the same value need not be set due to differences in volume between the first housing 10A and the second housing 20A, etc.

[0066] The second memory 53 has a second count memory 53D in addition to a second threshold memory 53A1, a second concentration memory 53B, and a second drive operation table 53C. In addition to the first concentration threshold, the second threshold memory 53A1 stores a predetermined count value as a threshold for determining whether the refrigerant concentration in the second casing 20A continues to be below the LFL of the flammable concentration range. This predetermined count value is set to, for example, 2 to 3 times.

[0067] The second control unit 54A measures the refrigerant concentration within a second predetermined time during the second driving operation of the indoor fan 23 via the second sensor 31B. The second control unit 54A determines whether the refrigerant concentration within the second predetermined time has increased. If the refrigerant concentration within the second predetermined time has not increased, the second control unit 54A increments the count value by 1 and stores the count value in the second count memory 53D. The second control unit 54A determines whether the count value has reached a predetermined count value stored in the second threshold memory 53A1.

[0068] When the count value reaches and is equal to the predetermined count value, the second control unit 54A ends the second drive operation of the indoor fan 23. When the count value does not reach and is not equal to the predetermined count value, the second control unit 54A continues the second drive operation of the indoor fan 23.

[0069] FIG. 9 is an explanatory diagram showing an example of changes in refrigerant concentration during the second drive operation. For ease of explanation, the predetermined count value is set to two. In FIG. 9, the first control unit 44 starts the second drive operation after executing the first drive operation. As a result, the refrigerant concentration in the first casing 10A gradually decreases by continuing to drive the outdoor fan 15 for a first predetermined time as the second drive operation. Next, the first control unit 44 pauses the drive of the outdoor fan 15 for a second predetermined time after the first predetermined time of the second drive operation. Then, the first control unit 44 measures the refrigerant concentration multiple times within the second predetermined time and determines whether the refrigerant concentration in the first casing 10A has increased based on the change over time in the measurement results.

[0070] If the refrigerant concentration within the second predetermined time period increases, the first control unit 44 determines that refrigerant is leaking into the first housing 10A and continues the second drive operation.The first control unit 44 then continues drive operation of the outdoor fan 15 for a first predetermined time period as the second drive operation, and pauses drive of the outdoor fan 15 for a second predetermined time period after the first predetermined time period of the second drive operation has elapsed.

[0071] Then, first control unit 44 measures the refrigerant concentration multiple times within a second predetermined time period and determines whether the refrigerant concentration in first casing 10A has increased based on the change over time in the measurement results. If the refrigerant concentration within the second predetermined time period has not increased, first control unit 44 determines that there is no refrigerant leakage within first casing 10A and increments the count value by 1. After incrementing the count value by 1, first control unit 44 determines whether the count value has reached a predetermined count value.

[0072] If the count value does not reach the predetermined count value and is not the predetermined count value, the first control unit 44 continues the second drive operation. Then, the first control unit 44 continues the drive operation of the outdoor fan 15 for a first predetermined time as the second drive operation, and after the first predetermined time of the second drive operation has elapsed, stops the drive of the outdoor fan 15 for a second predetermined time.

[0073] Then, the first control unit 44 measures the refrigerant concentration multiple times within a second predetermined time period and determines whether the refrigerant concentration in the first casing 10A has increased based on the change over time in the measurement results. If the refrigerant concentration within the second predetermined time period has not increased, the first control unit 44 determines that there is no refrigerant leakage within the first casing 10A and increments the count value by 1. After incrementing the count value by 1, the first control unit 44 determines whether the count value has reached a predetermined count value. If the count value is the predetermined count value of "2," the first control unit 44 ends the second driving operation.

[0074] Fig. 10 is a flowchart showing an example of the processing operation of the first control unit 16A related to the outdoor fan control process of Example 2. In Fig. 10, if the refrigerant concentration in the first casing 10A has not increased within a second predetermined time period (step S18: No), the first control unit 44A increments the count value by 1 (step S21) and stores the count value in the first count memory 43D. The first control unit 44A determines whether the count value is a predetermined count value (step S22).

[0075] If the count value reaches and is equal to the predetermined count value (step S22: Yes), the first control unit 44A stops the second drive operation of the outdoor fan 15 (step S23) and ends the processing operation shown in Fig. 10. If the count value does not reach and is not equal to the predetermined count value (step S22: No), the first control unit 44A returns to the processing of step S16 and resumes the second drive operation of the outdoor fan 15.

[0076] 10 illustrates an example of a case where the outdoor fan 15 is controlled based on the refrigerant concentration in the first casing 10A of the outdoor unit 10 and a determination as to whether the refrigerant concentration has increased. However, the indoor fan 23 may also be controlled based on the refrigerant concentration in the second casing 20A of the indoor unit 20 and a determination as to whether the refrigerant concentration has increased, and this can be modified as appropriate.

[0077] The first control unit 16A of the second embodiment performs the second driving operation at least twice to reliably agitate the refrigerant due to residual leakage, thereby reducing the risk of ignition within the first housing 10A and ensuring safety.

[0078] The second control unit 24A performs the second driving operation at least twice to reliably agitate the refrigerant due to the residual leakage, thereby reducing the risk of ignition within the second casing 20A and ensuring safety.

[0079] For ease of explanation, the example has been given in which the first control unit 44A in the first control unit 16A of the outdoor unit 10 is used to perform the threshold determination of the refrigerant concentration in the first casing 10A, the determination of whether the refrigerant concentration has increased, and the threshold determination of the count value. Also, the example has been given in which the second control unit 54A in the second control unit 24A of the indoor unit 20 is used to perform the threshold determination of the refrigerant concentration in the second casing 20A, the determination of whether the refrigerant concentration has increased, and the threshold determination of the count value. However, the threshold determination of the refrigerant concentration in the first casing 10A and the second casing 20A, the determination of whether the refrigerant concentration has increased, and the threshold determination of the count value may be performed by either the first control unit 16A or the second control unit 24A, and this can be modified as appropriate.

[0080] For example, the second control unit 24A acquires the refrigerant concentration and count value in the first casing 10A from the first control unit 16A, and extracts the type of drive operation of the outdoor fan 15 from the first drive operation table 43C based on the refrigerant concentration and count value in the first casing 10A. The second control unit 24A then transmits the extracted type of drive operation of the outdoor fan 15 to the first control unit 16A. The first control unit 16A may then perform the drive operation of the outdoor fan 15 using the type of drive operation of the outdoor fan 15 acquired from the second control unit 24A.

[0081] For example, the first control unit 16A acquires the refrigerant concentration and count value in the second casing 20A from the second control unit 24A, and extracts the type of drive operation of the indoor fan 23 from the second drive operation table 53C based on the refrigerant concentration and count value in the second casing 20A. Then, the first control unit 16A transmits the extracted type of drive operation of the indoor fan 23 to the second control unit 24A. Then, the second control unit 24A may perform the drive operation of the indoor fan 23 using the type of drive operation of the indoor fan 23 acquired from the first control unit 16A.

[0082] In the air conditioner 1 of Example 1, the second drive operation is stopped when the refrigerant concentration does not increase within the second predetermined time of the second drive operation, but the second drive operation may be stopped and the third drive operation may be performed, and this embodiment will be described below as Example 3. Note that the same components as those in the air conditioner 1 of Example 1 are given the same reference numerals, and descriptions of the overlapping components and operations will be omitted. [Example]

[0083] Fig. 11 is a block diagram showing an example of the configuration of a first control unit 16B of Example 3. The first control unit 16B of Example 3 shown in Fig. 11 differs from the first control unit 16 of Example 1 in that, when the refrigerant concentration in the first casing 10A has not increased within a second predetermined time, the second drive operation of the outdoor fan 15 is stopped and then a third drive operation of the outdoor fan 15 is performed.

[0084] The first drive operation table 43C1 pre-stores drive details for a third drive operation in addition to the first and second drive operations. The third drive operation is an operation in which the second predetermined time, which is the period during which the outdoor fan 15 is stopped in the second drive operation, is changed to a third predetermined time that is longer than the second predetermined time.

[0085] Fig. 12 is a block diagram showing an example of the configuration of a second control unit 24B of Example 3. The second control unit 24B of Example 3 shown in Fig. 12 differs from the second control unit 24 of Example 1 in that, when the refrigerant concentration in the second casing 20A has not increased within a second predetermined time, the second control unit 24B stops the second driving operation of the indoor fan 23 and then performs a third driving operation of the indoor fan 23.

[0086] The second drive operation table 53C1 pre-stores drive details for a third drive operation in addition to the first and second drive operations. The third drive operation is an operation in which the second predetermined time, which is the period during which the outdoor fan 15 is stopped in the second drive operation, is changed to a third predetermined time that is longer than the second predetermined time.

[0087] FIG. 13 is a flowchart showing an example of the processing operation of the first control unit 16B related to the outdoor fan control process of the third embodiment. In FIG. 13, the first control unit 44B in the first control unit 16B stops the second drive operation in step S19 and then starts the third drive operation of the outdoor fan 15 (step S31). Although not shown in FIG. 13, the third drive operation performs control similar to that of the second drive operation. Specifically, the first control unit 44B measures the refrigerant concentration in the first casing 10A multiple times within a third predetermined time and determines the change in the refrigerant concentration over time from the measurement results within the third predetermined time. Based on the determined change in the refrigerant concentration over time, the first control unit 44B determines whether the refrigerant concentration in the first casing 10A has increased within the third predetermined time. If the first control unit 44B determines that the refrigerant concentration in the first casing 10A has increased, it resumes the second drive operation of the outdoor fan 15. When the first control unit 44B determines that the refrigerant concentration in the first casing 10A has not increased, it stops the third driving operation (step S32) and ends the processing operation shown in FIG.

[0088] In the third embodiment, the first control unit 16B executes the third drive operation, which has a longer second predetermined time period than the second drive operation, when the refrigerant concentration in the first housing 10A has not increased. This makes it easier to detect the continuation of a refrigerant leak. As a result, the risk of ignition in the first housing 10A can be reduced, ensuring safety.

[0089] When the refrigerant concentration in the second housing 20A is not increasing, the second control unit 24B executes a third drive operation for a longer second predetermined time period than the second drive operation. This makes it easier to detect continued refrigerant leakage. As a result, the risk of ignition in the second housing 20A can be reduced, ensuring safety.

[0090] 13 illustrates an example in which the outdoor fan 15 is controlled based on the refrigerant concentration in the first casing 10A of the outdoor unit 10. However, the indoor fan 23 may also be controlled based on the refrigerant concentration in the second casing 20A of the indoor unit 20, and this can be modified as appropriate.

[0091] For ease of explanation, the example has been given in which the first control unit 44B in the first control unit 16B of the outdoor unit 10 is used to determine the threshold value of the refrigerant concentration in the first casing 10A and to determine whether the refrigerant concentration has increased within the second predetermined time. The example also has been given in which the second control unit 54B in the second control unit 24B of the indoor unit 20 is used to determine the threshold value of the refrigerant concentration in the second casing 20A and to determine whether the refrigerant concentration has increased within the second predetermined time. However, the threshold value of the refrigerant concentration in the first casing 10A and the second casing 20A and the determination whether the refrigerant concentration has increased within the second predetermined time may be determined by either the first control unit 16B or the second control unit 24B, and this can be changed as appropriate.

[0092] For example, the second control unit 24B acquires the refrigerant concentration in the first casing 10A from the first control unit 16B, and extracts the type of drive operation of the outdoor fan 15 from the first drive operation table 43C1 based on the refrigerant concentration in the first casing 10A. The second control unit 24B then transmits the extracted type of drive operation of the outdoor fan 15 to the first control unit 16B. The first control unit 16B may then perform the drive operation of the outdoor fan 15 using the type of drive operation of the outdoor fan 15 acquired from the second control unit 24B.

[0093] For example, the first control unit 16B obtains the refrigerant concentration in the second casing 20A from the second control unit 24B, and extracts the type of drive operation of the indoor fan 23 from the second drive operation table 53C1 based on the refrigerant concentration in the second casing 20A. Then, the first control unit 16B transmits the extracted type of drive operation of the indoor fan 23 to the second control unit 24B. Then, the second control unit 24B may perform the drive operation of the indoor fan 23 using the type of drive operation of the indoor fan 23 obtained from the first control unit 16B. [Explanation of symbols]

[0094] 1. Air conditioning equipment 10 Outdoor unit 10A First enclosure 15 Outdoor fan 20 Indoor unit 20A second enclosure 23 Indoor fan 31A First Sensor 31B Second Sensor 44 First control section 54 Second control section

Claims

1. An air conditioning apparatus having a housing, a heat exchanger and a fan through which a refrigerant accommodated in the housing flows, a sensor for detecting the concentration of the refrigerant within the housing, and a control unit for controlling the rotation speed of the fan, The control unit measuring the concentration of the refrigerant, which is the detected value of the sensor; When the concentration exceeds a first concentration threshold, a first driving operation is performed for a predetermined time to drive the fan to agitate the air inside the housing; After the first driving operation is performed, a second driving operation is performed in which the fan is intermittently driven; An air conditioning apparatus characterized in that if the concentration increases while the second driving operation is being performed, the second driving operation is continued, and if the concentration does not increase, the second driving operation is terminated and the driving of the fan is stopped.

2. The second driving operation includes:

2. The air conditioner according to claim 1, wherein the driving operation is stopped for a second predetermined time period after the driving operation is continued for a first predetermined time period.

3. The control unit The air conditioning apparatus according to claim 1, characterized in that, when an increase in the concentration is detected during execution of the second driving operation, the first driving operation is executed instead of continuing the second driving operation.

4. The control unit 3. The air conditioning apparatus according to claim 2, wherein when it is detected multiple times that the concentration does not increase, the second driving operation is terminated and the driving of the fan is stopped.

5. The control unit The air conditioning apparatus according to claim 4, characterized in that, when it is detected that the concentration is not increasing, a third driving operation is performed in which the second predetermined time in the second driving operation is changed to a third predetermined time that is longer than the second predetermined time.

6. The refrigerant is 2. The air conditioner according to claim 1, wherein the lower limit of the flammable concentration range is less than 13.3 Vol %.

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