Air-conditioning apparatus

Abstract

An air-conditioning apparatus is provided with a housing; a drain pan that is provided at the housing and receives drain water generated in the housing; a discharge module that is provided at the housing and at which an inlet port is formed through which drain water that remains on the drain pan is drawn in, the discharge module being configured to discharge drain water from the inlet port; and a water level sensor configured to detect that drain water reaches a set water level that is located higher than the inlet port of the discharge module.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an air-conditioning apparatus that detects drainage failure of drain water.BACKGROUND ART

[0002] Some air-conditioning apparatus is known that detects drainage failure of drain water. In general, among abnormalities that occur in a drain pan, drainage failure of drain water caused by factors such as a biofilm is particularly likely to occur in summer. Examples of drainage failure of drain water include a case where drain water is not smoothly drained due to clogged drain pipes and malfunction of rotation of a drain pump. When drain water is not properly drained, the water level of the drain water rises in the drain pan. Here, the air-conditioning apparatus is set to stop operation when the drain water in the drain pan reaches a preset water level. For this reason, when drain water is not properly drained and the water level of the drain water rises and reaches the preset water level, the air-conditioning apparatus is forcibly stopped. In this case, sudden maintenance such as the cleaning of the drain pan and the drain pipe is required. When drain water is not properly drained frequently in summer, the maintenance load increases accordingly.

[0003] Some air-conditioning apparatus is known that detects the water level of drain water on the basis of the activation state of a drain discharge means that discharges the drain water, as a technique for reporting the occurrence of drainage failure before the air-conditioning apparatus forcibly stops operation. Patent Literature 1 discloses an air-conditioning apparatus provided with an ultrasonic water level sensor located above a drain pan. Also, Patent Literature 1 discloses an air-conditioning apparatus provided with a capacitive water level sensor located at an outer wall side surface of the drain pan. These water level sensors each detect continuous changes in water level without physical contact. In Patent Literature 1, whether drainage failure occurs in the drain pan is determined by comparing the activation state of the drain discharge means with changes in water level during normal operation. Here, in Patent Literature 1, the drain water discharge means is activated when the drain pan is in a state where no drain water remains in the drain pan due to evaporation, and the activation state of the drain discharge means and changes in water level during normal operation are compared with each other. Also, in Patent Literature 1, changes in water level of water returned when the drain discharge means is stopped and changes in water level during normal operation are compared with each other. Based on this determination, the occurrence of drainage failure is reported.CITATION LISTPatent Literature

[0004] Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2008-96002SUMMARY OF INVENTIONTechnical Problem

[0005] However, the air-conditioning apparatus disclosed in Patent Literature 1 is unable to detect the occurrence of drainage failure under conditions such as during operation startup immediately after the drain discharge means is activated from a state where drain water is present until the water level stabilizes, during continuous operation, and during heating operation and fan operation in which drain water is rarely present. That is, in Patent Literature 1, because whether drainage failure is present is not always detected during operation of the air-conditioning apparatus, there is a possibility that the water level of drain water reaches a preset water level and operation of the air-conditioning apparatus stops before drainage failure is detected, and that subsequently recognition of the occurrence of drainage failure is delayed. There is a possibility that a user or an administrator is unable to recognize the occurrence of drainage failure until the operation of the air-conditioning apparatus stops and that sudden maintenance is required.

[0006] The present disclosure is made to solve such a problem described above, and an object of the present disclosure is to provide an air-conditioning apparatus that requires no sudden maintenance.Solution to Problem

[0007] An air-conditioning apparatus according to an embodiment of the present disclosure is provided with a housing; a drain pan that is provided at the housing and receives drain water generated in the housing; a discharge module that is provided at the housing and at which an inlet port is formed through which drain water that remains on the drain pan is drawn in, the discharge module being configured to discharge drain water from the inlet port; and a water level sensor configured to detect that drain water reaches a set water level that is located higher than the inlet port of the discharge module.Advantageous Effects of Invention

[0008] According to an embodiment of the present disclosure, the set water level of the water level sensor is positioned higher than the inlet port of the discharge module. In a case where drain water is not properly drained, irrespective of whether drain water has remained on the drain pan in advance, drain water is not easily discharged and the water level rises above the inlet port. For this reason, in a case where the water level sensor detects that drain water reaches the set water level, it is determined that drain water is not properly drained. As described above, it is possible to detect the occurrence of drainage failure of drain water at any timing, such as at operation startup, during continuous operation, and at operation shutdown. Therefore, sudden maintenance is no longer required.BRIEF DESCRIPTION OF DRAWINGS

[0009] FIG. 1 is a circuit diagram that illustrates an air-conditioning apparatus according to Embodiment 1.

[0010] FIG. 2 is a schematic diagram that illustrates the process of detecting a water level according to Embodiment 1.

[0011] FIG. 3 is a schematic diagram that illustrates a water level sensor according to Embodiment 1.

[0012] FIG. 4 is an explanatory diagram that illustrates, in a state where drain water is present on a drain pan when the air-conditioning apparatus according to Embodiment 1 starts cooling operation, changes in water level of drain water at which the water level in the absence of drainage failure and the water level in the presence of drainage failure differ from each other.

[0013] FIG. 5 is an explanatory diagram that illustrates, in a state where drain water is present on the drain pan when the air-conditioning apparatus according to Embodiment 1 starts cooling operation, changes in water level of the drain water at which the water level in the absence of drainage failure and the water level in the presence of drainage failure are substantially the same.

[0014] FIG. 6 is an explanatory diagram that illustrates, in a state where drain water is almost absent on the drain pan when the air-conditioning apparatus according to Embodiment 1 starts operation, changes in water level in the absence of drainage failure and in the presence of drainage failure.

[0015] FIG. 7 is an explanatory diagram that illustrates, after the air-conditioning apparatus according to Embodiment 1 performs operation for a specified period of time, changes in water level in the absence of drainage failure and in the presence of drainage failure.

[0016] FIG. 8 is an explanatory diagram that illustrates, when a discharge module operates after the air-conditioning apparatus according to Embodiment 1 stops operation, changes in water level in the absence of drainage failure and in the presence of drainage failure.

[0017] FIG. 9 is a schematic diagram that illustrates the process of detecting a water level according to Embodiment 2.

[0018] FIG. 10 is an explanatory diagram that illustrates, in a state where drain water is present on a drain pan when an air-conditioning apparatus according to Embodiment 2 starts cooling operation, changes in water level of the drain water at which the water level in the absence of drainage failure and the water level in the presence of drainage failure are substantially the same.DESCRIPTION OF EMBODIMENTS

[0019] Embodiments of an air-conditioning apparatus of the present disclosure are described below with reference to drawings. Note that the present disclosure is not limited to the embodiments described below. Also, the relative size of a component in the drawings illustrated below, which includes FIG. 1, may differ from its actual size. Also, in the explanation described below, directional terms used as appropriate for ease of comprehension of the present disclosure are merely for explanation of the present disclosure and the present disclosure is not limited by such directional terms. Examples of the directional terms include “upper”, “lower”, “right”, “left”, “front”, and “back”.Embodiment 1

[0020] FIG. 1 is a circuit diagram that illustrates an air-conditioning apparatus 40 according to Embodiment 1. The air-conditioning apparatus 40 is a device that conditions air in an indoor space and is, as illustrated in FIG. 1, provided with an outdoor unit 41 and an indoor unit 42. The outdoor unit 41 is provided with, for example, a compressor 50, a flow switching device 45, an outdoor heat exchanger 46, an outdoor air-sending device 47, and an expansion module 48. The indoor unit 42 is provided with, for example, a heat exchanger 4, an indoor air-sending device 49, and a controller 30.

[0021] The compressor 50, the flow switching device 45, the outdoor heat exchanger 46, the expansion module 48, and the heat exchanger 4 are connected by a refrigerant pipe 44 and a refrigerant circuit 43 is thereby formed. The compressor 50 draws in refrigerant in a low-temperature and low-pressure state, compresses the drawn refrigerant into refrigerant in a high-temperature and high-pressure state, and then discharges the refrigerant. The compressor 50 is, for example, an inverter compressor capable of capacity control. The flow switching device 45 switches directions in which refrigerant flows in the refrigerant circuit 43 and is, for example, a four-way valve. The outdoor heat exchanger 46 exchanges heat, for example, between outdoor air and refrigerant. The outdoor heat exchanger 46 serves as a condenser in cooling operation and serves as an evaporator in heating operation.

[0022] The expansion module 48 is a pressure reducing valve or an expansion valve that decompresses and expands refrigerant. The expansion module 48 is, for example, an electronic expansion valve with its opening degree adjustable.

[0023] The heat exchanger 4 exchanges heat, for example, between indoor air and refrigerant. The heat exchanger 4 serves as an evaporator in cooling operation and serves as a condenser in heating operation. The indoor air-sending device 49 is a device that sends indoor air to the heat exchanger 4.

[0024] Note that the air-conditioning apparatus 40 does not have to have the flow switching device 45. In this case, the air-conditioning apparatus 40 serves as a cooling-only unit or a heating-only unit.Detection of Water Level

[0025] FIG. 2 is a schematic diagram that illustrates the process of detecting a water level according to Embodiment 1. Next, the detection of the water level is described. As illustrated in FIG. 2, inside a housing 20 of the indoor unit 42, in addition to the heat exchanger 4 and the controller 30, a drain pan 1, a discharge module 2, a drain pipe 5, a humidifying device 14, and a water level sensor 3 are provided. The drain pan 1 receives drain water 9 generated inside the housing 20. The drain pan 1 is provided below the heat exchanger 4 and the humidifier and receives condensed water 10 generated at the heat exchanger 4 and the humidifying device 14.

[0026] The discharge module 2 discharges the drain water 9, which remains on the drain pan 1, and is provided above the drain pan 1. At a lower portion of the discharge module 2, an inlet port 12 is formed. Through the inlet port 12, the drain water 9, which remains on the drain pan 1, is drawn in. When the position of the water level of the drain water 9, which remains on the drain pan 1, rises above the position of the inlet port 12, the discharge module 2 draws in the drain water 9 from the inlet port 12. The discharge module 2 discharges the drain water 9 drawn in from the inlet port 12 into the drain pipe 5. The drain pipe 5 is connected to the discharge module 2 and through which the drain water 9 discharged from the discharge module 2 flows. The humidifying device 14 is attached to a wall surface of the drain pan 1.

[0027] The water level sensor 3 is of a float switch type (on-off switch) with a reed switch employed. Note that the water level sensor 3 may also be of a continuous water level detection type such as a capacitive type and an ultrasonic type. Also, the water level sensor 3 may also detect the water level by contacting the drain water 9 and may also detect the water level without contacting the drain water 9. The water level sensor 3 detects the water levels at at least two points. The present Embodiment 1 exemplifies a case where the water level sensor 3 detects the water levels at two points.

[0028] The water level sensor 3 detects a preset water level and a set water level. The preset water level is positioned at the higher one of the two points and is set at a position in the vicinity of the level at which the drain water 9, which remains on the drain pan 1, reaches full capacity. The air-conditioning apparatus 40 stops operation in a case where it is detected by the water level sensor 3 that the drain water 9 reaches the preset water level. With this configuration, the drain water 9 is prevented from leaking from the drain pan 1. The set water level is positioned at the lower one of the two points and is positioned above the inlet port 12 formed at the discharge module 2. Note that the location above the drain pan 1 where the water level sensor 3 is installed is not limited as long as the location falls within a range in which the water level of the drain water 9 is detectable. Here, the drain water 9 generated during cooling operation is, as described above, the condensed water 10 generated at the heat exchanger 4 and the humidifying device 14.

[0029] FIG. 3 is a schematic diagram that illustrates the water level sensor 3 according to Embodiment 1. As illustrated in FIG. 3, the water level sensor 3 has a lower float 3A and an upper float 3B, each of which surrounds a shaft 3C. The lower float 3A is used to determine the occurrence of drainage failure. The upper float 3B is used to detect a full state where the water level of the drain water 9 in the drain pan 1 reaches the preset water level. In a case where the upper float 3B is turned on, the operation of the air-conditioning apparatus 40 stops.Controller 30

[0030] Next, the controller 30 is described. The controller 30 controls the operation of the air-conditioning apparatus 40. Here, the hardware configuration of the controller 30 is described. The controller 30 is formed by a processor circuit. The processor circuit is formed by dedicated hardware or a processor. Examples of the dedicated hardware include circuits such as an application specific integrated circuit (ASIC) and a field programmable gate array (FPGA). The processor executes a program stored in a memory. The controller 30 has an unillustrated memory. The memory is non-volatile or volatile semiconductor memory such as a random access memory (RAM), a read only memory (ROM), a flash memory, and an erasable programmable ROM (EPROM) or a disk such as a magnetic disk, a flexible disk, and an optical disk.

[0031] As illustrated in FIG. 2, the controller 30 has water level output circuitry 6, determination circuitry 7, and transmission circuitry 8. The water level output circuitry 6, the determination circuitry 7, and the transmission circuitry 8 are formed by, for example, algorithms. The water level output circuitry 6 receives and outputs detection results from the water level sensor 3. The determination circuitry 7 determines that drainage failure occurs at the discharge module 2 in a case where the information that indicates that the drain water 9 reaches the set water level is output by the water level output circuitry 6. Also, the determination circuitry 7 determines that drainage failure occurs at the discharge module 2 in a case where the drain water 9 reaches the set water level when a predetermined time threshold elapses after the discharge module 2 operates.

[0032] The transmission circuitry 8 transmits determination results from the determination circuitry 7 to an external component. The external component is, for example, a display module 13 provided outside the air-conditioning apparatus 40. The display module 13 is, for example, a display medium provided on a remote control or in the cloud. A user is able to recognize a determination result of drainage failure displayed on the display module 13. Therefore, prompt action is enabled to address drainage failure of the drain water 9 before drainage failure causes the drain water 9, which remains on the drain pan 1, to reach the preset water level and then to stop the operation of the air-conditioning apparatus 40.Causes of Drainage Failure

[0033] Next, causes of drainage failure are described. Examples of causes of drainage failure include a biofilm 11. The biofilm 11, which is also referred to as slime, is a composite aggregate that includes, in addition to bacteria or mold, adhesive polysaccharides produced by the metabolism of bacteria or mold and impurities present in the air. The biofilm 11 is viscous. When it attaches to and accumulates on a wall surface of the discharge module 2, the drain pipe 5, or the drain pan 1, the drain water 9 is not able to be discharged.Water Level Status of Drain Pan

[0034] Next, the water level status of the drain pan 1 is described. While the air-conditioning apparatus 40 is performing cooling operation, the drain water 9 is being generated from the heat exchanger 4 and the humidifying device 14 and the drain water 9 is being discharged by the discharge module 2. Even while the drain water 9 is being discharged, it remains in a state of constant presence on the drain pan 1 during cooling operation. Subsequently, when the air-conditioning apparatus 40 stops operation and the discharge module 2 is also deactivated, the drain water 9 present in the drain pipe 5 while the drain water 9 is being pumped up flows back. With this backflow, the amount of the drain water 9 present in the drain pipe 5 is added to the drain water 9 originally present on the drain pan 1 and the water level of the drain water 9 on the drain pan 1 rises. The drain water 9, which remains on the drain pan 1 after the air-conditioning apparatus 40 stops, gradually evaporates in a case where the air-conditioning apparatus 40 does not operate for a long time and then the drain water 9 transitions to a state of absence on the drain pan 1. Therefore, the state on the drain pan 1 at the start of cooling operation may be in a state where the drain water 9 is evaporating but is still present and in another state where the drain water 9 completely evaporates and is then absent. Also, the amount of the drain water 9 present on the drain pan 1 is not always constant because the amount is affected by the operational status and the installation environment of the air-conditioning apparatus 40.Detection of Drainage Failure in Case Where Drain Water 9 Remains at Operation Startup

[0035] Next, detection of the occurrence of drainage failure under a condition at operation startup when the air-conditioning apparatus 40 is activated is described. This condition refers to a state where the time from the previous operation shutdown of the air-conditioning apparatus 40 to the current start of cooling operation of the air-conditioning apparatus 40 is short and the drain water 9 on the drain pan 1 is hardly evaporating. In this state, the water level of the drain water 9 at operation startup is above the inlet port 12 of the discharge module 2. When a water level L is set above the position of the inlet port of the drain water 9, that is, when a switch that turns on and off the lower float 3A is set (set water level), the lower float 3A of the water level sensor 3 transitions to the switch-on state at operation startup. Here, the water level may be in a case where the water level in the presence of drainage failure is higher than the water level in the absence of drainage failure and in another case where the water level in the absence of drainage failure and the water level in the presence of drainage failure are the same.Case Where Water Level in Presence of Drainage Failure is Higher than Water Level in Absence of Drainage Failure

[0036] FIG. 4 is an explanatory diagram that illustrates, in a state where the drain water 9 is present on the drain pan 1 when the air-conditioning apparatus 40 according to Embodiment 1 starts cooling operation, changes in water level of the drain water 9 at which the water level in the absence of drainage failure and the water level in the presence of drainage failure differ from each other. As illustrated in FIG. 4, after the air-conditioning apparatus 40 starts cooling operation, the discharge module 2 is activated, and the drain water 9 on the drain pan 1 starts to be discharged. Subsequently, when the amount of the condensed water 10 generated from the heat exchanger 4 and the humidifying device 14 and the amount discharged by the discharge module 2 reach a state of equilibrium, the water level of the drain water 9 becomes constant at the position of the inlet port 12 of the discharge module 2. Therefore, when drainage failure does not occur, the lower float 3A switches from the on state to the off state.

[0037] On the other hand, when drainage failure occurs, the water level of the drain water 9 is higher than when drainage failure does not occur. For this reason, even when the discharge module 2 is activated and the drain water 9 on the drain pan 1 starts to be discharged, the position at which the water level becomes constant is the position at which the lower float 3A is in the on state. Therefore, with reference to whether the lower float 3A is in the on state or in the off state at a time when the water level is constant, it is possible to recognize the absence of the occurrence of drainage failure and the presence of drainage failure. In a case where the lower float 3A is in the on state, the determination circuitry 7 determines the possibility of the presence of drainage failure. The information determined by the determination circuitry 7 is sent to the transmission circuitry 8 and the information is sent from the transmission circuitry 8 to the display module 13 provided outside the air-conditioning apparatus 40. With this configuration, a user is able to recognize the occurrence of drainage failure. After a user is informed, the user is able to perform maintenance according to their usage conditions. Therefore, it is possible to prevent in advance both the drain water 9 from reaching the preset water level and from reaching full capacity and the air-conditioning apparatus 40 from unexpectedly stopping operation. Note that information of the timing of the presence of drainage failure and data on the water level of the timing of the presence of drainage failure are able to be accumulated in the cloud.Case Where Water Level in Absence of Drainage Failure and Water Level in Presence of Drainage Failure are the Same

[0038] FIG. 5 is an explanatory diagram that illustrates, in a state where the drain water 9 is present on the drain pan 1 when the air-conditioning apparatus 40 according to Embodiment 1 starts cooling operation, changes in water level of the drain water 9 at which the water level in the absence of drainage failure and the water level in the presence of drainage failure are substantially the same. As illustrated in FIG. 5, the behavior in the absence of the occurrence of drainage failure is the same as that illustrated in FIG. 4. On the other hand, when drainage failure occurs, two patterns of behavior are considered. The first pattern is a case where the occurrence of drainage failure reduces the discharge speed of the drain water 9 and causes the water level, which is thereby made constant, to be higher than the water level L. The second pattern is a case where the discharge module 2 discharges no drain water 9 or where the generation speed of the condensed water 10 from the heat exchanger 4 and the humidifying device 14 is greater than the discharge speed of the drain water 9 by the discharge module 2, and the water level of the drain water 9 appears to rise. In either case, in both the first pattern and the second pattern, the lower float 3A remains in the switch-on state.

[0039] Therefore, with reference to whether the lower float 3A is in the on state or in the off state at a time when the water level is constant, it is possible to recognize the absence of the occurrence of drainage failure and the presence of drainage failure. In a case where the lower float 3A is in the on state, the determination circuitry 7 determines the possibility of the presence of drainage failure. The information determined by the determination circuitry 7 is sent to the transmission circuitry 8 and the information is sent from the transmission circuitry 8 to the display module 13 provided outside the air-conditioning apparatus 40. With this configuration, a user is able to recognize the occurrence of drainage failure. After a user is informed, the user is able to perform maintenance according to their usage conditions. Therefore, it is possible to prevent in advance both the drain water 9 from reaching the preset water level and from reaching full capacity and the air-conditioning apparatus 40 from unexpectedly stopping operation. Note that information of the timing of the presence of drainage failure and data on the water level of the timing of the presence of drainage failure are able to be accumulated in the cloud.Detection of Drainage Failure in Case Where Drain Water 9 is Almost Absent at Operation Startup

[0040] FIG. 6 is an explanatory diagram that illustrates, in a state where the drain water 9 is almost absent on the drain pan 1 when the air-conditioning apparatus 40 according to Embodiment 1 starts operation, changes in water level in the absence of drainage failure and in the presence of drainage failure. This condition refers to a state where the time from the previous operation shutdown of the air-conditioning apparatus 40 to the current start of cooling operation of the air-conditioning apparatus 40 is long and the drain water 9 on the drain pan 1 is evaporating. In this state, the water level of the drain water 9 at operation startup is below the inlet port 12 of the discharge module 2. When a water level L is set above the position of the inlet port of the drain water 9, that is, when a switch that turns on and off the lower float 3A is set (set water level), the float 3A of the water level sensor 3 transitions to the switch-off state at operation startup.

[0041] In the absence of drainage failure, after cooling operation is started, the discharge module 2 discharges no drain water 9 and the condensed water 10 generated from the heat exchanger 4 and the humidifying device 14 remains on the drain pan 1. For this reason, the generation speed of the condensed water 10 from the heat exchanger 4 and the humidifying device 14 is greater than the discharge speed of the drain water 9 and the water level of the drain water 9 appears to rise. Subsequently, when the generation speed of the condensed water 10 and the discharge speed of the drain water 9 stabilize, the water level of the drain water 9 becomes constant. That is, in the absence of drainage failure, the lower float 3A remains in the off state.

[0042] In the presence of drainage failure, after cooling operation is started, the discharge module 2 discharges no drain water 9 or the generation speed of the condensed water 10 from the heat exchanger 4 and the humidifying device 14 is greater than the discharge speed of the drain water 9 by the discharge module 2. As a result, the condensed water 10 generated from the heat exchanger 4 and the humidifying device 14 remains on the drain pan 1 and the drain water 9 rises. In the presence of drainage failure, the water level of the drain water 9 rises and the lower float 3A transitions to the on state. Therefore, with reference to whether the lower float 3A is in the on state or in the off state at a time when the water level is constant, it is possible to recognize the absence of the occurrence of drainage failure and the presence of drainage failure. In a case where the lower float 3A is in the on state, the determination circuitry 7 determines the possibility of the presence of drainage failure. The information determined by the determination circuitry 7 is sent to the transmission circuitry 8 and the information is sent from the transmission circuitry 8 to the display module 13 provided outside the air-conditioning apparatus 40. With this configuration, a user is able to recognize the occurrence of drainage failure. After a user is informed, the user is able to perform maintenance according to their usage conditions. Therefore, it is possible to prevent in advance both the drain water 9 from reaching the preset water level and from reaching full capacity and the air-conditioning apparatus 40 from unexpectedly stopping operation. Note that information of the timing of the presence of drainage failure and data on the water level of the timing of the presence of drainage failure are able to be accumulated in the cloud.Detection of Drainage Failure during Continuous Operation

[0043] Next, detection of the occurrence of drainage failure under a condition in which the air-conditioning apparatus 40 continuously operates for an arbitrary time is described. When a water level L is set above the position of the inlet port of the drain water 9, that is, when a switch that turns on and off the lower float 3A is set (set water level), the lower float 3A of the water level sensor 3 transitions to the switch-on state at operation startup.

[0044] FIG. 7 is an explanatory diagram that illustrates, after the air-conditioning apparatus 40 according to Embodiment 1 performs operation for a specified period of time, changes in water level in the absence of drainage failure and in the presence of drainage failure. As illustrated in FIG. 7, during continuous operation of the air-conditioning apparatus 40 and in the absence of drainage failure, the amount of the condensed water 10 generated from the heat exchanger 4 and the humidifying device 14 and the amount discharged by the discharge module 2 reach a state of equilibrium and the water level is constant. On the other hand, in the presence of drainage failure, the discharge speed of the drain water 9 by the discharge module 2 decreases, the generation speed of the condensed water 10 increases, and, as a result, the water level of the drain water 9 appears to rise. In the absence of drainage failure, the lower float 3A remains in the off state. On the other hand, in the presence of drainage failure, the water level of the drain water 9 rises and the lower float 3A transitions to the on state.

[0045] Therefore, with reference to whether the lower float 3A is in the on state or in the off state, it is possible to recognize the absence of drainage failure and the presence of drainage failure. In a case where the lower float 3A is in the on state, the determination circuitry 7 determines the possibility of the presence of drainage failure. The information determined by the determination circuitry 7 is sent to the transmission circuitry 8 and the information is sent from the transmission circuitry 8 to the display module 13 provided outside the air-conditioning apparatus 40. With this configuration, a user is able to recognize the occurrence of drainage failure. After a user is informed, the user is able to perform maintenance according to their usage conditions. Therefore, it is possible to prevent in advance both the drain water 9 from reaching the preset water level and from reaching full capacity and the air-conditioning apparatus 40 from unexpectedly stopping operation. Note that information of the timing of the presence of drainage failure and data on the water level of the timing of the presence of drainage failure are able to be accumulated in the cloud.Detection of Drainage Failure After Operation Shutdown

[0046] Next, detection of the occurrence of drainage failure under a condition in which the air-conditioning apparatus 40 stops operation is described. This condition refers to a case where the water level L is set above the position of the inlet port of the drain water 9, that is, where a switch that turns on and off the lower float 3A is set (set water level) and the water level rise due to drain water backflow at operation shutdown causes the lower float 3A of the water level sensor 3 to transition to the switch-on state. Also, a time point T at which the discharge module 2 is started to operate again is stored in the controller 30 in advance.

[0047] FIG. 8 is an explanatory diagram that illustrates, when the discharge module 2 operates after the air-conditioning apparatus 40 according to Embodiment 1 stops operation, changes in water level in the absence of drainage failure and in the presence of drainage failure. When the air-conditioning apparatus 40 stops operation and the discharge module 2 is also deactivated, the drain water 9 being pumped up and present in the drain pipe 5 flows back. With this backflow, the drain water 9 present in the drain pipe 5 is added to the drain water 9 originally present on the drain pan 1 and, as illustrated in FIG. 8, the water level of the drain water 9 on the drain pan 1 rises.

[0048] In the absence of drainage failure, when the discharge module 2 is activated again, the drain water 9 is discharged by the discharge module 2. As in the absence of drainage failure, in the presence of drainage failure, the discharge module 2 is activated and the discharge of the drain water 9 is started. However, the discharge speed of the drain water 9 is lower than that in the absence of drainage failure. This is because the occurrence of drainage failure reduces the discharge speed of the drain water 9. The determination circuitry 7 determines the absence of drainage failure when the drain water 9 is discharged by the discharge module 2 and the lower float 3A transitions to the off state. On the other hand, when the water level is higher than the water level L, that is, when the lower float 3A is in the on state, the determination circuitry 7 determines the possibility of the presence of drainage failure.

[0049] Therefore, with reference to whether the lower float 3A is in the on state or in the off state, it is possible to recognize the absence of the occurrence of drainage failure and the presence of drainage failure, In a case where the lower float 3A is in the on state, the determination circuitry 7 determines the possibility of the presence of drainage failure. The information determined by the determination circuitry 7 is sent to the transmission circuitry 8 and the information is sent from the transmission circuitry 8 to the display module 13 provided outside the air-conditioning apparatus 40. With this configuration, a user is able to recognize the occurrence of drainage failure. After a user is informed, the user is able to perform maintenance according to their usage conditions. Therefore, it is possible to prevent in advance both the drain water 9 from reaching the preset water level and from reaching full capacity and the air-conditioning apparatus 40 from unexpectedly stopping operation. Note that information of the timing of the presence of drainage failure and data on the water level of the timing of the presence of drainage failure are able to be accumulated in the cloud.

[0050] As described above, in either state, in a case where the lower float 3A is in the on state, the determination circuitry 7 determines the possibility of the presence of drainage failure. Only by determining whether the lower float 3A is in the on state or in the off state, it is possible to recognize the absence of the occurrence of drainage failure and the presence of drainage failure.

[0051] According to the present Embodiment 1, the set water level of the water level sensor 3 is positioned higher than the inlet port 12 of the discharge module 2. In a case where the drain water 9 is not properly drained, irrespective of whether the drain water 9 has remained on the drain pan 1 in advance, the drain water 9 is not easily discharged and the water level rises above the inlet port 12. For this reason, in a case where the water level sensor 3 detects that the drain water 9 reaches the set water level, it is determined that the drain water 9 is not properly drained. As described above, it is possible to detect the occurrence of drainage failure of the drain water 9 at any timing, such as at operation startup, during continuous operation, and at operation shutdown. Therefore, sudden maintenance is no longer required. This configuration makes it possible to discover, at an early stage, the occurrence of drainage failure that remains undiscovered in some air-conditioning apparatus 40 until it stops operation. Also, it is possible to determine whether drainage failure occurs for each air-conditioning apparatus 40 limited to only one of the following conditions: at operation startup, during continuous operation, and at operation shutdown. Furthermore, it is possible to determine whether drainage failure occurs under two conditions such as at operation startup and at operation shutdown. Operational statuses are freely combinable.Embodiment 2

[0052] FIG. 9 is a schematic diagram that illustrates the process of detecting the water level according to Embodiment 2. The present Embodiment 2 differs from Embodiment 1 in the configuration of the water level sensor 3. Components in the present Embodiment 2 that are the same as Embodiment 1 have the same reference signs and are not described below. Differences from Embodiment 1 are mainly described.

[0053] FIG. 9 corresponds to FIG. 3 of Embodiment 1. The water level sensor 3 detects the water levels at at least two points. However, its type differs from that of Embodiment 1. As the water level sensor 3, a float switch type that has three or more on-off switches among float 3D switch types or a continuous type such as a float type, a capacitive type, and an ultrasonic type is employed. As illustrated in FIG. 9, a float switch type provided with three or more on-off switches or a continuous type (a float type) has a float 3D, which surrounds the shaft 3C. For example, with an electromagnetic induction type, the float 3D moves up and down and the water level is thereby continuously detected. Also, in a case where a continuous type is employed, the water level sensor 3 detects the water level when the drain water 9 is present on the drain pan 1 while the air-conditioning apparatus 40 is operating.Case Where Water Level in Absence of Drainage Failure and Water Level in Presence of Drainage Failure are the Same

[0054] FIG. 10 is an explanatory diagram that illustrates, in a state where the drain water 9 is present on the drain pan 1 when the air-conditioning apparatus 40 according to Embodiment 2 starts cooling operation, changes in water level of the drain water 9 at which the water level in the absence of drainage failure and the water level in the presence of drainage failure are substantially the same. Here, as illustrated in FIG. 10, a case is described where the water level in the absence of drainage failure and the water level in the presence of drainage failure are the same. The controller 30 determines that drainage failure occurs at the discharge module 2 in a case where a change in water level detected by the water level sensor 3 differs from a change in water level in the absence of drainage failure stored in advance. The water level sensor 3 continuously detects changes in the water level from the start of activation of the indoor unit 42. In the water level sensor 3, the water level at which the drain pan 1 is full of water is set in advance. When the water level sensor 3 detects this water level, the air-conditioning apparatus 40 stops.

[0055] The determination circuitry 7 of the controller 30 compares a change in water level continuously detected by the water level sensor 3 with a change in water level in the absence of drainage failure. The determination circuitry 7 of the controller 30 determines the possibility of the presence of drainage failure in a case where the change in water level obtained by the water level sensor 3 does not match the change in water level in the absence of drainage failure. Note that the controller 30 may also learn respective patterns of drainage states in advance. The information determined by the determination circuitry 7 is sent to the transmission circuitry 8 and the information is sent from the transmission circuitry 8 to the display module 13 provided outside the air-conditioning apparatus 40. With this configuration, a user is able to recognize the occurrence of drainage failure. After a user is informed, the user is able to perform maintenance according to their usage conditions. Therefore, it is possible to prevent in advance both the drain water 9 from reaching the preset water level and from reaching full capacity and the air-conditioning apparatus 40 from unexpectedly stopping operation. Note that information of the timing of the presence of drainage failure and data on the water level of the timing of the presence of drainage failure are able to be accumulated in the cloud.

[0056] Note that the determination of the occurrence of drainage failure in Embodiment 2 is also applicable to FIG. 4, FIG. 5, FIG. 6, FIG. 7, and FIG. 8 in Embodiment 1.REFERENCE SIGNS LIST

[0057] 1: drain pan, 2: discharge module, 3: water level sensor, 3A: lower float, 3B: upper float, 3C: shaft, 3D: float, 4: heat exchanger, 5: drain pipe, 6: water level output circuitry, 7: determination circuitry, 8: transmission circuitry, 9: drain water, 10: condensed water, 11: biofilm, 12: inlet port, 13: display module, 14: humidifying device, 20: housing, 30: controller, 40: air-conditioning apparatus, 41: outdoor unit,42: indoor unit, 43: refrigerant circuit, 44: refrigerant pipe, 45: flow switching device, 46: outdoor heat exchanger, 47: outdoor air-sending device, 48: expansion module, 49: indoor air-sending device, 50: compressor

Examples

embodiment 1

[0020]FIG. 1 is a circuit diagram that illustrates an air-conditioning apparatus 40 according to Embodiment 1. The air-conditioning apparatus 40 is a device that conditions air in an indoor space and is, as illustrated in FIG. 1, provided with an outdoor unit 41 and an indoor unit 42. The outdoor unit 41 is provided with, for example, a compressor 50, a flow switching device 45, an outdoor heat exchanger 46, an outdoor air-sending device 47, and an expansion module 48. The indoor unit 42 is provided with, for example, a heat exchanger 4, an indoor air-sending device 49, and a controller 30.

[0021]The compressor 50, the flow switching device 45, the outdoor heat exchanger 46, the expansion module 48, and the heat exchanger 4 are connected by a refrigerant pipe 44 and a refrigerant circuit 43 is thereby formed. The compressor 50 draws in refrigerant in a low-temperature and low-pressure state, compresses the drawn refrigerant into refrigerant in a high-temperature and high-pressure sta...

embodiment 2

[0052]FIG. 9 is a schematic diagram that illustrates the process of detecting the water level according to Embodiment 2. The present Embodiment 2 differs from Embodiment 1 in the configuration of the water level sensor 3. Components in the present Embodiment 2 that are the same as Embodiment 1 have the same reference signs and are not described below. Differences from Embodiment 1 are mainly described.

[0053]FIG. 9 corresponds to FIG. 3 of Embodiment 1. The water level sensor 3 detects the water levels at at least two points. However, its type differs from that of Embodiment 1. As the water level sensor 3, a float switch type that has three or more on-off switches among float 3D switch types or a continuous type such as a float type, a capacitive type, and an ultrasonic type is employed. As illustrated in FIG. 9, a float switch type provided with three or more on-off switches or a continuous type (a float type) has a float 3D, which surrounds the shaft 3C. For example, with an electr...

TECHNICAL FIELD

[0001] The present disclosure relates to an air-conditioning apparatus that detects drainage failure of drain water.BACKGROUND ART

[0002] Some air-conditioning apparatus is known that detects drainage failure of drain water. In general, among abnormalities that occur in a drain pan, drainage failure of drain water caused by factors such as a biofilm is particularly likely to occur in summer. Examples of drainage failure of drain water include a case where drain water is not smoothly drained due to clogged drain pipes and malfunction of rotation of a drain pump. When drain water is not properly drained, the water level of the drain water rises in the drain pan. Here, the air-conditioning apparatus is set to stop operation when the drain water in the drain pan reaches a preset water level. For this reason, when drain water is not properly drained and the water level of the drain water rises and reaches the preset water level, the air-conditioning apparatus is forcibly stopped. In this case, sudden maintenance such as the cleaning of the drain pan and the drain pipe is required. When drain water is not properly drained frequently in summer, the maintenance load increases accordingly.

[0003] Some air-conditioning apparatus is known that detects the water level of drain water on the basis of the activation state of a drain discharge means that discharges the drain water, as a technique for reporting the occurrence of drainage failure before the air-conditioning apparatus forcibly stops operation. Patent Literature 1 discloses an air-conditioning apparatus provided with an ultrasonic water level sensor located above a drain pan. Also, Patent Literature 1 discloses an air-conditioning apparatus provided with a capacitive water level sensor located at an outer wall side surface of the drain pan. These water level sensors each detect continuous changes in water level without physical contact. In Patent Literature 1, whether drainage failure occurs in the drain pan is determined by comparing the activation state of the drain discharge means with changes in water level during normal operation. Here, in Patent Literature 1, the drain water discharge means is activated when the drain pan is in a state where no drain water remains in the drain pan due to evaporation, and the activation state of the drain discharge means and changes in water level during normal operation are compared with each other. Also, in Patent Literature 1, changes in water level of water returned when the drain discharge means is stopped and changes in water level during normal operation are compared with each other. Based on this determination, the occurrence of drainage failure is reported.CITATION LISTPatent Literature

[0004] Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2008-96002SUMMARY OF INVENTIONTechnical Problem

[0005] However, the air-conditioning apparatus disclosed in Patent Literature 1 is unable to detect the occurrence of drainage failure under conditions such as during operation startup immediately after the drain discharge means is activated from a state where drain water is present until the water level stabilizes, during continuous operation, and during heating operation and fan operation in which drain water is rarely present. That is, in Patent Literature 1, because whether drainage failure is present is not always detected during operation of the air-conditioning apparatus, there is a possibility that the water level of drain water reaches a preset water level and operation of the air-conditioning apparatus stops before drainage failure is detected, and that subsequently recognition of the occurrence of drainage failure is delayed. There is a possibility that a user or an administrator is unable to recognize the occurrence of drainage failure until the operation of the air-conditioning apparatus stops and that sudden maintenance is required.

[0006] The present disclosure is made to solve such a problem described above, and an object of the present disclosure is to provide an air-conditioning apparatus that requires no sudden maintenance.Solution to Problem

[0007] An air-conditioning apparatus according to an embodiment of the present disclosure is provided with a housing; a drain pan that is provided at the housing and receives drain water generated in the housing; a discharge module that is provided at the housing and at which an inlet port is formed through which drain water that remains on the drain pan is drawn in, the discharge module being configured to discharge drain water from the inlet port; and a water level sensor configured to detect that drain water reaches a set water level that is located higher than the inlet port of the discharge module.Advantageous Effects of Invention

[0008] According to an embodiment of the present disclosure, the set water level of the water level sensor is positioned higher than the inlet port of the discharge module. In a case where drain water is not properly drained, irrespective of whether drain water has remained on the drain pan in advance, drain water is not easily discharged and the water level rises above the inlet port. For this reason, in a case where the water level sensor detects that drain water reaches the set water level, it is determined that drain water is not properly drained. As described above, it is possible to detect the occurrence of drainage failure of drain water at any timing, such as at operation startup, during continuous operation, and at operation shutdown. Therefore, sudden maintenance is no longer required.BRIEF DESCRIPTION OF DRAWINGS

[0009] FIG. 1 is a circuit diagram that illustrates an air-conditioning apparatus according to Embodiment 1.

[0010] FIG. 2 is a schematic diagram that illustrates the process of detecting a water level according to Embodiment 1.

[0011] FIG. 3 is a schematic diagram that illustrates a water level sensor according to Embodiment 1.

[0012] FIG. 4 is an explanatory diagram that illustrates, in a state where drain water is present on a drain pan when the air-conditioning apparatus according to Embodiment 1 starts cooling operation, changes in water level of drain water at which the water level in the absence of drainage failure and the water level in the presence of drainage failure differ from each other.

[0013] FIG. 5 is an explanatory diagram that illustrates, in a state where drain water is present on the drain pan when the air-conditioning apparatus according to Embodiment 1 starts cooling operation, changes in water level of the drain water at which the water level in the absence of drainage failure and the water level in the presence of drainage failure are substantially the same.

[0014] FIG. 6 is an explanatory diagram that illustrates, in a state where drain water is almost absent on the drain pan when the air-conditioning apparatus according to Embodiment 1 starts operation, changes in water level in the absence of drainage failure and in the presence of drainage failure.

[0015] FIG. 7 is an explanatory diagram that illustrates, after the air-conditioning apparatus according to Embodiment 1 performs operation for a specified period of time, changes in water level in the absence of drainage failure and in the presence of drainage failure.

[0016] FIG. 8 is an explanatory diagram that illustrates, when a discharge module operates after the air-conditioning apparatus according to Embodiment 1 stops operation, changes in water level in the absence of drainage failure and in the presence of drainage failure.

[0017] FIG. 9 is a schematic diagram that illustrates the process of detecting a water level according to Embodiment 2.

[0018] FIG. 10 is an explanatory diagram that illustrates, in a state where drain water is present on a drain pan when an air-conditioning apparatus according to Embodiment 2 starts cooling operation, changes in water level of the drain water at which the water level in the absence of drainage failure and the water level in the presence of drainage failure are substantially the same.DESCRIPTION OF EMBODIMENTS

[0019] Embodiments of an air-conditioning apparatus of the present disclosure are described below with reference to drawings. Note that the present disclosure is not limited to the embodiments described below. Also, the relative size of a component in the drawings illustrated below, which includes FIG. 1, may differ from its actual size. Also, in the explanation described below, directional terms used as appropriate for ease of comprehension of the present disclosure are merely for explanation of the present disclosure and the present disclosure is not limited by such directional terms. Examples of the directional terms include “upper”, “lower”, “right”, “left”, “front”, and “back”.Embodiment 1

[0020] FIG. 1 is a circuit diagram that illustrates an air-conditioning apparatus 40 according to Embodiment 1. The air-conditioning apparatus 40 is a device that conditions air in an indoor space and is, as illustrated in FIG. 1, provided with an outdoor unit 41 and an indoor unit 42. The outdoor unit 41 is provided with, for example, a compressor 50, a flow switching device 45, an outdoor heat exchanger 46, an outdoor air-sending device 47, and an expansion module 48. The indoor unit 42 is provided with, for example, a heat exchanger 4, an indoor air-sending device 49, and a controller 30.

[0021] The compressor 50, the flow switching device 45, the outdoor heat exchanger 46, the expansion module 48, and the heat exchanger 4 are connected by a refrigerant pipe 44 and a refrigerant circuit 43 is thereby formed. The compressor 50 draws in refrigerant in a low-temperature and low-pressure state, compresses the drawn refrigerant into refrigerant in a high-temperature and high-pressure state, and then discharges the refrigerant. The compressor 50 is, for example, an inverter compressor capable of capacity control. The flow switching device 45 switches directions in which refrigerant flows in the refrigerant circuit 43 and is, for example, a four-way valve. The outdoor heat exchanger 46 exchanges heat, for example, between outdoor air and refrigerant. The outdoor heat exchanger 46 serves as a condenser in cooling operation and serves as an evaporator in heating operation.

[0022] The expansion module 48 is a pressure reducing valve or an expansion valve that decompresses and expands refrigerant. The expansion module 48 is, for example, an electronic expansion valve with its opening degree adjustable.

[0023] The heat exchanger 4 exchanges heat, for example, between indoor air and refrigerant. The heat exchanger 4 serves as an evaporator in cooling operation and serves as a condenser in heating operation. The indoor air-sending device 49 is a device that sends indoor air to the heat exchanger 4.

[0024] Note that the air-conditioning apparatus 40 does not have to have the flow switching device 45. In this case, the air-conditioning apparatus 40 serves as a cooling-only unit or a heating-only unit.Detection of Water Level

[0025] FIG. 2 is a schematic diagram that illustrates the process of detecting a water level according to Embodiment 1. Next, the detection of the water level is described. As illustrated in FIG. 2, inside a housing 20 of the indoor unit 42, in addition to the heat exchanger 4 and the controller 30, a drain pan 1, a discharge module 2, a drain pipe 5, a humidifying device 14, and a water level sensor 3 are provided. The drain pan 1 receives drain water 9 generated inside the housing 20. The drain pan 1 is provided below the heat exchanger 4 and the humidifier and receives condensed water 10 generated at the heat exchanger 4 and the humidifying device 14.

[0026] The discharge module 2 discharges the drain water 9, which remains on the drain pan 1, and is provided above the drain pan 1. At a lower portion of the discharge module 2, an inlet port 12 is formed. Through the inlet port 12, the drain water 9, which remains on the drain pan 1, is drawn in. When the position of the water level of the drain water 9, which remains on the drain pan 1, rises above the position of the inlet port 12, the discharge module 2 draws in the drain water 9 from the inlet port 12. The discharge module 2 discharges the drain water 9 drawn in from the inlet port 12 into the drain pipe 5. The drain pipe 5 is connected to the discharge module 2 and through which the drain water 9 discharged from the discharge module 2 flows. The humidifying device 14 is attached to a wall surface of the drain pan 1.

[0027] The water level sensor 3 is of a float switch type (on-off switch) with a reed switch employed. Note that the water level sensor 3 may also be of a continuous water level detection type such as a capacitive type and an ultrasonic type. Also, the water level sensor 3 may also detect the water level by contacting the drain water 9 and may also detect the water level without contacting the drain water 9. The water level sensor 3 detects the water levels at at least two points. The present Embodiment 1 exemplifies a case where the water level sensor 3 detects the water levels at two points.

[0028] The water level sensor 3 detects a preset water level and a set water level. The preset water level is positioned at the higher one of the two points and is set at a position in the vicinity of the level at which the drain water 9, which remains on the drain pan 1, reaches full capacity. The air-conditioning apparatus 40 stops operation in a case where it is detected by the water level sensor 3 that the drain water 9 reaches the preset water level. With this configuration, the drain water 9 is prevented from leaking from the drain pan 1. The set water level is positioned at the lower one of the two points and is positioned above the inlet port 12 formed at the discharge module 2. Note that the location above the drain pan 1 where the water level sensor 3 is installed is not limited as long as the location falls within a range in which the water level of the drain water 9 is detectable. Here, the drain water 9 generated during cooling operation is, as described above, the condensed water 10 generated at the heat exchanger 4 and the humidifying device 14.

[0029] FIG. 3 is a schematic diagram that illustrates the water level sensor 3 according to Embodiment 1. As illustrated in FIG. 3, the water level sensor 3 has a lower float 3A and an upper float 3B, each of which surrounds a shaft 3C. The lower float 3A is used to determine the occurrence of drainage failure. The upper float 3B is used to detect a full state where the water level of the drain water 9 in the drain pan 1 reaches the preset water level. In a case where the upper float 3B is turned on, the operation of the air-conditioning apparatus 40 stops.Controller 30

[0030] Next, the controller 30 is described. The controller 30 controls the operation of the air-conditioning apparatus 40. Here, the hardware configuration of the controller 30 is described. The controller 30 is formed by a processor circuit. The processor circuit is formed by dedicated hardware or a processor. Examples of the dedicated hardware include circuits such as an application specific integrated circuit (ASIC) and a field programmable gate array (FPGA). The processor executes a program stored in a memory. The controller 30 has an unillustrated memory. The memory is non-volatile or volatile semiconductor memory such as a random access memory (RAM), a read only memory (ROM), a flash memory, and an erasable programmable ROM (EPROM) or a disk such as a magnetic disk, a flexible disk, and an optical disk.

[0031] As illustrated in FIG. 2, the controller 30 has water level output circuitry 6, determination circuitry 7, and transmission circuitry 8. The water level output circuitry 6, the determination circuitry 7, and the transmission circuitry 8 are formed by, for example, algorithms. The water level output circuitry 6 receives and outputs detection results from the water level sensor 3. The determination circuitry 7 determines that drainage failure occurs at the discharge module 2 in a case where the information that indicates that the drain water 9 reaches the set water level is output by the water level output circuitry 6. Also, the determination circuitry 7 determines that drainage failure occurs at the discharge module 2 in a case where the drain water 9 reaches the set water level when a predetermined time threshold elapses after the discharge module 2 operates.

[0032] The transmission circuitry 8 transmits determination results from the determination circuitry 7 to an external component. The external component is, for example, a display module 13 provided outside the air-conditioning apparatus 40. The display module 13 is, for example, a display medium provided on a remote control or in the cloud. A user is able to recognize a determination result of drainage failure displayed on the display module 13. Therefore, prompt action is enabled to address drainage failure of the drain water 9 before drainage failure causes the drain water 9, which remains on the drain pan 1, to reach the preset water level and then to stop the operation of the air-conditioning apparatus 40.Causes of Drainage Failure

[0033] Next, causes of drainage failure are described. Examples of causes of drainage failure include a biofilm 11. The biofilm 11, which is also referred to as slime, is a composite aggregate that includes, in addition to bacteria or mold, adhesive polysaccharides produced by the metabolism of bacteria or mold and impurities present in the air. The biofilm 11 is viscous. When it attaches to and accumulates on a wall surface of the discharge module 2, the drain pipe 5, or the drain pan 1, the drain water 9 is not able to be discharged.Water Level Status of Drain Pan

[0034] Next, the water level status of the drain pan 1 is described. While the air-conditioning apparatus 40 is performing cooling operation, the drain water 9 is being generated from the heat exchanger 4 and the humidifying device 14 and the drain water 9 is being discharged by the discharge module 2. Even while the drain water 9 is being discharged, it remains in a state of constant presence on the drain pan 1 during cooling operation. Subsequently, when the air-conditioning apparatus 40 stops operation and the discharge module 2 is also deactivated, the drain water 9 present in the drain pipe 5 while the drain water 9 is being pumped up flows back. With this backflow, the amount of the drain water 9 present in the drain pipe 5 is added to the drain water 9 originally present on the drain pan 1 and the water level of the drain water 9 on the drain pan 1 rises. The drain water 9, which remains on the drain pan 1 after the air-conditioning apparatus 40 stops, gradually evaporates in a case where the air-conditioning apparatus 40 does not operate for a long time and then the drain water 9 transitions to a state of absence on the drain pan 1. Therefore, the state on the drain pan 1 at the start of cooling operation may be in a state where the drain water 9 is evaporating but is still present and in another state where the drain water 9 completely evaporates and is then absent. Also, the amount of the drain water 9 present on the drain pan 1 is not always constant because the amount is affected by the operational status and the installation environment of the air-conditioning apparatus 40.Detection of Drainage Failure in Case Where Drain Water 9 Remains at Operation Startup

[0035] Next, detection of the occurrence of drainage failure under a condition at operation startup when the air-conditioning apparatus 40 is activated is described. This condition refers to a state where the time from the previous operation shutdown of the air-conditioning apparatus 40 to the current start of cooling operation of the air-conditioning apparatus 40 is short and the drain water 9 on the drain pan 1 is hardly evaporating. In this state, the water level of the drain water 9 at operation startup is above the inlet port 12 of the discharge module 2. When a water level L is set above the position of the inlet port of the drain water 9, that is, when a switch that turns on and off the lower float 3A is set (set water level), the lower float 3A of the water level sensor 3 transitions to the switch-on state at operation startup. Here, the water level may be in a case where the water level in the presence of drainage failure is higher than the water level in the absence of drainage failure and in another case where the water level in the absence of drainage failure and the water level in the presence of drainage failure are the same.Case Where Water Level in Presence of Drainage Failure is Higher than Water Level in Absence of Drainage Failure

[0036] FIG. 4 is an explanatory diagram that illustrates, in a state where the drain water 9 is present on the drain pan 1 when the air-conditioning apparatus 40 according to Embodiment 1 starts cooling operation, changes in water level of the drain water 9 at which the water level in the absence of drainage failure and the water level in the presence of drainage failure differ from each other. As illustrated in FIG. 4, after the air-conditioning apparatus 40 starts cooling operation, the discharge module 2 is activated, and the drain water 9 on the drain pan 1 starts to be discharged. Subsequently, when the amount of the condensed water 10 generated from the heat exchanger 4 and the humidifying device 14 and the amount discharged by the discharge module 2 reach a state of equilibrium, the water level of the drain water 9 becomes constant at the position of the inlet port 12 of the discharge module 2. Therefore, when drainage failure does not occur, the lower float 3A switches from the on state to the off state.

[0037] On the other hand, when drainage failure occurs, the water level of the drain water 9 is higher than when drainage failure does not occur. For this reason, even when the discharge module 2 is activated and the drain water 9 on the drain pan 1 starts to be discharged, the position at which the water level becomes constant is the position at which the lower float 3A is in the on state. Therefore, with reference to whether the lower float 3A is in the on state or in the off state at a time when the water level is constant, it is possible to recognize the absence of the occurrence of drainage failure and the presence of drainage failure. In a case where the lower float 3A is in the on state, the determination circuitry 7 determines the possibility of the presence of drainage failure. The information determined by the determination circuitry 7 is sent to the transmission circuitry 8 and the information is sent from the transmission circuitry 8 to the display module 13 provided outside the air-conditioning apparatus 40. With this configuration, a user is able to recognize the occurrence of drainage failure. After a user is informed, the user is able to perform maintenance according to their usage conditions. Therefore, it is possible to prevent in advance both the drain water 9 from reaching the preset water level and from reaching full capacity and the air-conditioning apparatus 40 from unexpectedly stopping operation. Note that information of the timing of the presence of drainage failure and data on the water level of the timing of the presence of drainage failure are able to be accumulated in the cloud.Case Where Water Level in Absence of Drainage Failure and Water Level in Presence of Drainage Failure are the Same

[0038] FIG. 5 is an explanatory diagram that illustrates, in a state where the drain water 9 is present on the drain pan 1 when the air-conditioning apparatus 40 according to Embodiment 1 starts cooling operation, changes in water level of the drain water 9 at which the water level in the absence of drainage failure and the water level in the presence of drainage failure are substantially the same. As illustrated in FIG. 5, the behavior in the absence of the occurrence of drainage failure is the same as that illustrated in FIG. 4. On the other hand, when drainage failure occurs, two patterns of behavior are considered. The first pattern is a case where the occurrence of drainage failure reduces the discharge speed of the drain water 9 and causes the water level, which is thereby made constant, to be higher than the water level L. The second pattern is a case where the discharge module 2 discharges no drain water 9 or where the generation speed of the condensed water 10 from the heat exchanger 4 and the humidifying device 14 is greater than the discharge speed of the drain water 9 by the discharge module 2, and the water level of the drain water 9 appears to rise. In either case, in both the first pattern and the second pattern, the lower float 3A remains in the switch-on state.

[0039] Therefore, with reference to whether the lower float 3A is in the on state or in the off state at a time when the water level is constant, it is possible to recognize the absence of the occurrence of drainage failure and the presence of drainage failure. In a case where the lower float 3A is in the on state, the determination circuitry 7 determines the possibility of the presence of drainage failure. The information determined by the determination circuitry 7 is sent to the transmission circuitry 8 and the information is sent from the transmission circuitry 8 to the display module 13 provided outside the air-conditioning apparatus 40. With this configuration, a user is able to recognize the occurrence of drainage failure. After a user is informed, the user is able to perform maintenance according to their usage conditions. Therefore, it is possible to prevent in advance both the drain water 9 from reaching the preset water level and from reaching full capacity and the air-conditioning apparatus 40 from unexpectedly stopping operation. Note that information of the timing of the presence of drainage failure and data on the water level of the timing of the presence of drainage failure are able to be accumulated in the cloud.Detection of Drainage Failure in Case Where Drain Water 9 is Almost Absent at Operation Startup

[0040] FIG. 6 is an explanatory diagram that illustrates, in a state where the drain water 9 is almost absent on the drain pan 1 when the air-conditioning apparatus 40 according to Embodiment 1 starts operation, changes in water level in the absence of drainage failure and in the presence of drainage failure. This condition refers to a state where the time from the previous operation shutdown of the air-conditioning apparatus 40 to the current start of cooling operation of the air-conditioning apparatus 40 is long and the drain water 9 on the drain pan 1 is evaporating. In this state, the water level of the drain water 9 at operation startup is below the inlet port 12 of the discharge module 2. When a water level L is set above the position of the inlet port of the drain water 9, that is, when a switch that turns on and off the lower float 3A is set (set water level), the float 3A of the water level sensor 3 transitions to the switch-off state at operation startup.

[0041] In the absence of drainage failure, after cooling operation is started, the discharge module 2 discharges no drain water 9 and the condensed water 10 generated from the heat exchanger 4 and the humidifying device 14 remains on the drain pan 1. For this reason, the generation speed of the condensed water 10 from the heat exchanger 4 and the humidifying device 14 is greater than the discharge speed of the drain water 9 and the water level of the drain water 9 appears to rise. Subsequently, when the generation speed of the condensed water 10 and the discharge speed of the drain water 9 stabilize, the water level of the drain water 9 becomes constant. That is, in the absence of drainage failure, the lower float 3A remains in the off state.

[0042] In the presence of drainage failure, after cooling operation is started, the discharge module 2 discharges no drain water 9 or the generation speed of the condensed water 10 from the heat exchanger 4 and the humidifying device 14 is greater than the discharge speed of the drain water 9 by the discharge module 2. As a result, the condensed water 10 generated from the heat exchanger 4 and the humidifying device 14 remains on the drain pan 1 and the drain water 9 rises. In the presence of drainage failure, the water level of the drain water 9 rises and the lower float 3A transitions to the on state. Therefore, with reference to whether the lower float 3A is in the on state or in the off state at a time when the water level is constant, it is possible to recognize the absence of the occurrence of drainage failure and the presence of drainage failure. In a case where the lower float 3A is in the on state, the determination circuitry 7 determines the possibility of the presence of drainage failure. The information determined by the determination circuitry 7 is sent to the transmission circuitry 8 and the information is sent from the transmission circuitry 8 to the display module 13 provided outside the air-conditioning apparatus 40. With this configuration, a user is able to recognize the occurrence of drainage failure. After a user is informed, the user is able to perform maintenance according to their usage conditions. Therefore, it is possible to prevent in advance both the drain water 9 from reaching the preset water level and from reaching full capacity and the air-conditioning apparatus 40 from unexpectedly stopping operation. Note that information of the timing of the presence of drainage failure and data on the water level of the timing of the presence of drainage failure are able to be accumulated in the cloud.Detection of Drainage Failure during Continuous Operation

[0043] Next, detection of the occurrence of drainage failure under a condition in which the air-conditioning apparatus 40 continuously operates for an arbitrary time is described. When a water level L is set above the position of the inlet port of the drain water 9, that is, when a switch that turns on and off the lower float 3A is set (set water level), the lower float 3A of the water level sensor 3 transitions to the switch-on state at operation startup.

[0044] FIG. 7 is an explanatory diagram that illustrates, after the air-conditioning apparatus 40 according to Embodiment 1 performs operation for a specified period of time, changes in water level in the absence of drainage failure and in the presence of drainage failure. As illustrated in FIG. 7, during continuous operation of the air-conditioning apparatus 40 and in the absence of drainage failure, the amount of the condensed water 10 generated from the heat exchanger 4 and the humidifying device 14 and the amount discharged by the discharge module 2 reach a state of equilibrium and the water level is constant. On the other hand, in the presence of drainage failure, the discharge speed of the drain water 9 by the discharge module 2 decreases, the generation speed of the condensed water 10 increases, and, as a result, the water level of the drain water 9 appears to rise. In the absence of drainage failure, the lower float 3A remains in the off state. On the other hand, in the presence of drainage failure, the water level of the drain water 9 rises and the lower float 3A transitions to the on state.

[0045] Therefore, with reference to whether the lower float 3A is in the on state or in the off state, it is possible to recognize the absence of drainage failure and the presence of drainage failure. In a case where the lower float 3A is in the on state, the determination circuitry 7 determines the possibility of the presence of drainage failure. The information determined by the determination circuitry 7 is sent to the transmission circuitry 8 and the information is sent from the transmission circuitry 8 to the display module 13 provided outside the air-conditioning apparatus 40. With this configuration, a user is able to recognize the occurrence of drainage failure. After a user is informed, the user is able to perform maintenance according to their usage conditions. Therefore, it is possible to prevent in advance both the drain water 9 from reaching the preset water level and from reaching full capacity and the air-conditioning apparatus 40 from unexpectedly stopping operation. Note that information of the timing of the presence of drainage failure and data on the water level of the timing of the presence of drainage failure are able to be accumulated in the cloud.Detection of Drainage Failure After Operation Shutdown

[0046] Next, detection of the occurrence of drainage failure under a condition in which the air-conditioning apparatus 40 stops operation is described. This condition refers to a case where the water level L is set above the position of the inlet port of the drain water 9, that is, where a switch that turns on and off the lower float 3A is set (set water level) and the water level rise due to drain water backflow at operation shutdown causes the lower float 3A of the water level sensor 3 to transition to the switch-on state. Also, a time point T at which the discharge module 2 is started to operate again is stored in the controller 30 in advance.

[0047] FIG. 8 is an explanatory diagram that illustrates, when the discharge module 2 operates after the air-conditioning apparatus 40 according to Embodiment 1 stops operation, changes in water level in the absence of drainage failure and in the presence of drainage failure. When the air-conditioning apparatus 40 stops operation and the discharge module 2 is also deactivated, the drain water 9 being pumped up and present in the drain pipe 5 flows back. With this backflow, the drain water 9 present in the drain pipe 5 is added to the drain water 9 originally present on the drain pan 1 and, as illustrated in FIG. 8, the water level of the drain water 9 on the drain pan 1 rises.

[0048] In the absence of drainage failure, when the discharge module 2 is activated again, the drain water 9 is discharged by the discharge module 2. As in the absence of drainage failure, in the presence of drainage failure, the discharge module 2 is activated and the discharge of the drain water 9 is started. However, the discharge speed of the drain water 9 is lower than that in the absence of drainage failure. This is because the occurrence of drainage failure reduces the discharge speed of the drain water 9. The determination circuitry 7 determines the absence of drainage failure when the drain water 9 is discharged by the discharge module 2 and the lower float 3A transitions to the off state. On the other hand, when the water level is higher than the water level L, that is, when the lower float 3A is in the on state, the determination circuitry 7 determines the possibility of the presence of drainage failure.

[0049] Therefore, with reference to whether the lower float 3A is in the on state or in the off state, it is possible to recognize the absence of the occurrence of drainage failure and the presence of drainage failure, In a case where the lower float 3A is in the on state, the determination circuitry 7 determines the possibility of the presence of drainage failure. The information determined by the determination circuitry 7 is sent to the transmission circuitry 8 and the information is sent from the transmission circuitry 8 to the display module 13 provided outside the air-conditioning apparatus 40. With this configuration, a user is able to recognize the occurrence of drainage failure. After a user is informed, the user is able to perform maintenance according to their usage conditions. Therefore, it is possible to prevent in advance both the drain water 9 from reaching the preset water level and from reaching full capacity and the air-conditioning apparatus 40 from unexpectedly stopping operation. Note that information of the timing of the presence of drainage failure and data on the water level of the timing of the presence of drainage failure are able to be accumulated in the cloud.

[0050] As described above, in either state, in a case where the lower float 3A is in the on state, the determination circuitry 7 determines the possibility of the presence of drainage failure. Only by determining whether the lower float 3A is in the on state or in the off state, it is possible to recognize the absence of the occurrence of drainage failure and the presence of drainage failure.

[0051] According to the present Embodiment 1, the set water level of the water level sensor 3 is positioned higher than the inlet port 12 of the discharge module 2. In a case where the drain water 9 is not properly drained, irrespective of whether the drain water 9 has remained on the drain pan 1 in advance, the drain water 9 is not easily discharged and the water level rises above the inlet port 12. For this reason, in a case where the water level sensor 3 detects that the drain water 9 reaches the set water level, it is determined that the drain water 9 is not properly drained. As described above, it is possible to detect the occurrence of drainage failure of the drain water 9 at any timing, such as at operation startup, during continuous operation, and at operation shutdown. Therefore, sudden maintenance is no longer required. This configuration makes it possible to discover, at an early stage, the occurrence of drainage failure that remains undiscovered in some air-conditioning apparatus 40 until it stops operation. Also, it is possible to determine whether drainage failure occurs for each air-conditioning apparatus 40 limited to only one of the following conditions: at operation startup, during continuous operation, and at operation shutdown. Furthermore, it is possible to determine whether drainage failure occurs under two conditions such as at operation startup and at operation shutdown. Operational statuses are freely combinable.Embodiment 2

[0052] FIG. 9 is a schematic diagram that illustrates the process of detecting the water level according to Embodiment 2. The present Embodiment 2 differs from Embodiment 1 in the configuration of the water level sensor 3. Components in the present Embodiment 2 that are the same as Embodiment 1 have the same reference signs and are not described below. Differences from Embodiment 1 are mainly described.

[0053] FIG. 9 corresponds to FIG. 3 of Embodiment 1. The water level sensor 3 detects the water levels at at least two points. However, its type differs from that of Embodiment 1. As the water level sensor 3, a float switch type that has three or more on-off switches among float 3D switch types or a continuous type such as a float type, a capacitive type, and an ultrasonic type is employed. As illustrated in FIG. 9, a float switch type provided with three or more on-off switches or a continuous type (a float type) has a float 3D, which surrounds the shaft 3C. For example, with an electromagnetic induction type, the float 3D moves up and down and the water level is thereby continuously detected. Also, in a case where a continuous type is employed, the water level sensor 3 detects the water level when the drain water 9 is present on the drain pan 1 while the air-conditioning apparatus 40 is operating.Case Where Water Level in Absence of Drainage Failure and Water Level in Presence of Drainage Failure are the Same

[0054] FIG. 10 is an explanatory diagram that illustrates, in a state where the drain water 9 is present on the drain pan 1 when the air-conditioning apparatus 40 according to Embodiment 2 starts cooling operation, changes in water level of the drain water 9 at which the water level in the absence of drainage failure and the water level in the presence of drainage failure are substantially the same. Here, as illustrated in FIG. 10, a case is described where the water level in the absence of drainage failure and the water level in the presence of drainage failure are the same. The controller 30 determines that drainage failure occurs at the discharge module 2 in a case where a change in water level detected by the water level sensor 3 differs from a change in water level in the absence of drainage failure stored in advance. The water level sensor 3 continuously detects changes in the water level from the start of activation of the indoor unit 42. In the water level sensor 3, the water level at which the drain pan 1 is full of water is set in advance. When the water level sensor 3 detects this water level, the air-conditioning apparatus 40 stops.

[0055] The determination circuitry 7 of the controller 30 compares a change in water level continuously detected by the water level sensor 3 with a change in water level in the absence of drainage failure. The determination circuitry 7 of the controller 30 determines the possibility of the presence of drainage failure in a case where the change in water level obtained by the water level sensor 3 does not match the change in water level in the absence of drainage failure. Note that the controller 30 may also learn respective patterns of drainage states in advance. The information determined by the determination circuitry 7 is sent to the transmission circuitry 8 and the information is sent from the transmission circuitry 8 to the display module 13 provided outside the air-conditioning apparatus 40. With this configuration, a user is able to recognize the occurrence of drainage failure. After a user is informed, the user is able to perform maintenance according to their usage conditions. Therefore, it is possible to prevent in advance both the drain water 9 from reaching the preset water level and from reaching full capacity and the air-conditioning apparatus 40 from unexpectedly stopping operation. Note that information of the timing of the presence of drainage failure and data on the water level of the timing of the presence of drainage failure are able to be accumulated in the cloud.

[0056] Note that the determination of the occurrence of drainage failure in Embodiment 2 is also applicable to FIG. 4, FIG. 5, FIG. 6, FIG. 7, and FIG. 8 in Embodiment 1.REFERENCE SIGNS LIST

[0057] 1: drain pan, 2: discharge module, 3: water level sensor, 3A: lower float, 3B: upper float, 3C: shaft, 3D: float, 4: heat exchanger, 5: drain pipe, 6: water level output circuitry, 7: determination circuitry, 8: transmission circuitry, 9: drain water, 10: condensed water, 11: biofilm, 12: inlet port, 13: display module, 14: humidifying device, 20: housing, 30: controller, 40: air-conditioning apparatus, 41: outdoor unit,42: indoor unit, 43: refrigerant circuit, 44: refrigerant pipe, 45: flow switching device, 46: outdoor heat exchanger, 47: outdoor air-sending device, 48: expansion module, 49: indoor air-sending device, 50: compressor

Examples

embodiment 1

[0020]FIG. 1 is a circuit diagram that illustrates an air-conditioning apparatus 40 according to Embodiment 1. The air-conditioning apparatus 40 is a device that conditions air in an indoor space and is, as illustrated in FIG. 1, provided with an outdoor unit 41 and an indoor unit 42. The outdoor unit 41 is provided with, for example, a compressor 50, a flow switching device 45, an outdoor heat exchanger 46, an outdoor air-sending device 47, and an expansion module 48. The indoor unit 42 is provided with, for example, a heat exchanger 4, an indoor air-sending device 49, and a controller 30.

[0021]The compressor 50, the flow switching device 45, the outdoor heat exchanger 46, the expansion module 48, and the heat exchanger 4 are connected by a refrigerant pipe 44 and a refrigerant circuit 43 is thereby formed. The compressor 50 draws in refrigerant in a low-temperature and low-pressure state, compresses the drawn refrigerant into refrigerant in a high-temperature and high-pressure sta...

embodiment 2

[0052]FIG. 9 is a schematic diagram that illustrates the process of detecting the water level according to Embodiment 2. The present Embodiment 2 differs from Embodiment 1 in the configuration of the water level sensor 3. Components in the present Embodiment 2 that are the same as Embodiment 1 have the same reference signs and are not described below. Differences from Embodiment 1 are mainly described.

[0053]FIG. 9 corresponds to FIG. 3 of Embodiment 1. The water level sensor 3 detects the water levels at at least two points. However, its type differs from that of Embodiment 1. As the water level sensor 3, a float switch type that has three or more on-off switches among float 3D switch types or a continuous type such as a float type, a capacitive type, and an ultrasonic type is employed. As illustrated in FIG. 9, a float switch type provided with three or more on-off switches or a continuous type (a float type) has a float 3D, which surrounds the shaft 3C. For example, with an electr...

Claims

1. An air-conditioning apparatus comprising:a housing;a drain pan that is provided at the housing and receives drain water generated in the housing;a discharge module that is provided at the housing and at which an inlet port is formed through which drain water that remains on the drain pan is drawn in, the discharge module being configured to discharge drain water from the inlet port; anda water level sensor configured to detect that drain water reaches a set water level that is located higher than the inlet port of the discharge module.

2. The air-conditioning apparatus of claim 1, further comprising a controller that haswater level output circuitry configured to receive and output a detection result from the water level sensor, anddetermination circuitry configured to determine that drainage failure occurs at the discharge module in a case where information that indicates drain water reaches the set water level is output by the water level output circuitry.

3. The air-conditioning apparatus of claim 2, wherein the determination circuitry is configured to determine that drainage failure occurs at the discharge module in a case where drain water reaches the set water level when a predetermined time threshold elapses after the discharge module operates.

4. The air-conditioning apparatus of claim 2, wherein the controller further has transmission circuitry configured to transmit a determination result from the determination circuitry to an external component.

5. The air-conditioning apparatus of claim 4, wherein the controller is configured to cause a display module provided outside to display information transmitted by the transmission circuitry.

6. The air-conditioning apparatus of claim 1, wherein the water level sensor is configured to detect that drain water reaches the set water level and a preset water level at which drain water is prevented from overflowing from the drain pan.

7. (canceled)

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