Indoor unit of air conditioner

Abstract

To provide an indoor unit of an air conditioner which secures a time during which a sterilization material contacts with drain water flowing backward by its self weight when a drain pump is stopped to improve sterilization effect of the drain water.SOLUTION: An indoor unit 2 includes: a heat exchanger housed in a main part; a drain pan 6 which accumulates drain water occurring due to heat exchange of a heat exchanger; a drain pump 8 which pumps up the drain water accumulated in the drain pan 6; a drain hose 9 which discharges the drain water discharged by the drain pump 8 to the outside of the main part; a sterilization part 10 which sterilizes the drain water; and a control unit 4 which performs output control of the drain pump 8 in which the output is gradually lowered from driving of the drain pump 8 to the stoppage.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] An embodiment of the present invention relates to an indoor unit of an air conditioner. [Background technology]

[0002] An indoor unit of an air conditioner is known that includes an indoor unit body that is attached to the ceiling of a room to be air-conditioned, a heat exchanger housed in the indoor unit body, a drain pan that collects drain water discharged as a result of the heat exchange action of the heat exchanger, a drain pump that pumps up the drain water that has collected in the drain pan to direct it to a drainage system, and a semi-rigid drain hose with a bellows shape that directs the drain water discharged by the drain pump to the outside of the indoor unit body.

[0003] In addition, when the drain pump stops, the drain water in the drain hose and drain pump, etc., flows back due to its own weight, and when the drain water flows out of the suction port of the stopped drain pump into the drain pan, the drain water comes into contact with an antibacterial agent, thereby sterilizing the drain water in an indoor unit of an air conditioner. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-257622 [Patent Document 2] Japanese Patent Application Publication No. 2017-122526 Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional air conditioner indoor units, when the drain pump is stopped, the drain water flowing out from the drain pump's suction port is disinfected by contacting an antibacterial agent with the drain water, but the drain water flows out from the drain pump's suction port at a high speed, which could prevent sufficient disinfection.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an indoor unit for an air conditioner that can enhance the sterilization effect of drain water. [Means for solving the problem]

[0007] An indoor unit of an air conditioner according to an embodiment of the present invention comprises a main body that can be attached to the ceiling of a room to be air-conditioned, a heat exchanger housed in the main body, a drain pan that collects drain water resulting from heat exchange in the heat exchanger, a drain pump that pumps up the drain water that has collected in the drain pan, a drain hose that discharges the drain water discharged by the drain pump to the outside of the main body, a sterilization unit that sterilizes the drain water, and a control unit that controls the output of the drain pump so as to gradually reduce the output of the drain pump from operating to stopping.

[0008] In the indoor unit, it is preferable that the sterilization unit is disposed in a position where it can irradiate a sterilizing substance toward all or part of a lower region of the drain pump suction port, and sterilize all or part of the drain water. Furthermore, it is preferable that the sterilization unit irradiates ultraviolet light as the sterilizing substance toward the drain water accumulated in the drain pan. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view of an indoor unit of an air conditioner according to an embodiment of the present invention. [Figure 2] 1 is a plan view of an indoor unit of an air conditioner according to an embodiment of the present invention. [Figure 3] 1 is a front view of an indoor unit of an air conditioner according to an embodiment of the present invention. [Figure 4] FIG. 4 is an enlarged view of the left front inclined plate of the indoor unit of the air conditioner according to the present embodiment. [Figure 5] 2 is a schematic diagram showing an enlarged side view of the periphery of a drain pump provided in the indoor unit of the air conditioner according to the present embodiment, and a control unit. FIG. [Figure 6] FIG. 4 is a flowchart showing part of the operation of the indoor unit of the air conditioner according to the present embodiment. [Figure 7]FIG. 10 is a flowchart showing another part of the operation of the indoor unit of the air conditioner according to the embodiment. [Figure 8] FIG. 2 is a diagram for explaining a first method for sterilizing drain water accumulated in a drain pump provided in the indoor unit of the air conditioner according to the present embodiment. [Figure 9] FIG. 10 is a diagram for explaining a second method for sterilizing drain water accumulated in a drain pump provided in the indoor unit of the air conditioner according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of an indoor unit for an air conditioner according to the present invention will be described with reference to Figures 1 to 11. Note that the same or corresponding components are denoted by the same reference numerals throughout the drawings.

[0011] FIG. 1 is a perspective view of an indoor unit of an air conditioner according to an embodiment of the present invention.

[0012] FIG. 2 is a plan view of the indoor unit of the air conditioner according to the embodiment of the present invention.

[0013] FIG. 3 is a front view of the indoor unit of the air conditioner according to the embodiment of the present invention.

[0014] The air conditioner 1 according to this embodiment comprises an outdoor unit as a heat source installed outdoors, and an indoor unit 2 as a user installed indoors, as shown in FIG.

[0015] The air conditioner 1 also has a refrigeration cycle. The refrigeration cycle includes a heat exchanger on the heat source side, a compressor, a heat exchanger 3 on the user side, an expander, and refrigerant piping that circulates refrigerant through these devices. The air conditioner 1 may also have a four-way valve that switches between cooling operation and heating operation by switching the flow direction of the refrigerant in the refrigerant piping.

[0016] The indoor unit 2 houses a heat exchanger 3 on the user side of the refrigeration cycle. The outdoor unit houses a heat exchanger on the heat source side of the refrigeration cycle, a compressor, and a four-way valve. The electric expansion valve, which is an expansion machine, may be housed in either the indoor unit 2 or the outdoor unit. The outdoor unit and indoor unit are connected via a crossover pipe. The crossover pipe is part of the refrigerant pipe. The air conditioner 1 conditions the air in the room by circulating refrigerant between the heat exchanger on the outdoor unit side and the heat exchanger 3 on the indoor unit 2 side.

[0017] The installation location of the indoor unit 2, that is, the room to be air-conditioned, is, for example, a room in a building. The indoor unit 2 is installed by being embedded in the ceiling of the room to be air-conditioned. In other words, the indoor unit 2 is a so-called embedded type indoor unit.

[0018] 1 to 3, the indoor unit 2 according to this embodiment includes a housing 5 as a main body, a heat exchanger 3 provided within the housing 5, a blower 7 provided within the housing 5, a drain pan 6 provided within the housing 5 below the heat exchanger 3, and a decorative panel 19 covering the bottom surface of the housing 5. The blower 7 includes an annular bell mouth provided in the housing 5, and a fan that draws air through the bell mouth and blows the air toward the heat exchanger 3.

[0019] The housing 5 is a box-shaped body with a roughly square top, four rectangular sides, and an open bottom. The top of the housing 5 is closed by a top plate 11. A fan is provided on the underside of the top plate 11. The front, right side, left side, and back of the housing 5 are closed by side plates 12. The corners between a pair of adjacent side surfaces of the housing 5 are beveled rather than chamfered. This chamfered corner is closed by an inclined plate 13. The inclined plate 13 is inclined at 45 degrees relative to the adjacent side plate 12. In other words, the angle between the adjacent inclined plates 13 and side plates 12 is 135 degrees.

[0020] The housing 5 also includes support fittings 15 provided on each of the inclined plates 13. The support fittings 15 support the entire indoor unit 2 by being hooked onto nuts that are fastened to stud bolts that are provided to hang down from the ceiling.

[0021] In the air conditioner 1 shown in Figure 2, the lower side of the page is the front side and the upper side is the back side. The left-hand side is the left side face and the right-hand side is the right side face. In the air conditioner 1 shown in Figure 3, the lower side of the page is the bottom side and the upper side is the top side. The left-hand side is the left side face and the right-hand side is the right side face. The indoor unit 2 is installed with the top face facing upward and the bottom face facing downward. Therefore, the vertical direction of the indoor unit 2 is the direction that passes through the top and bottom faces. The above, below, front, rear, right side and left side of the indoor unit 2 are as shown in Figures 2 and 3.

[0022] The chamfered corner between the front and right side surfaces of the housing 5 has an inclined portion 13a and a stepped portion 13b offset toward the rear surface of the housing 5 in a plan view.

[0023] The step portion 13b is closed by the front right side plate 12fr and the right front side plate 12rf. Specifically, the front right side plate 12fr is disposed parallel to the front side plate 12f so as to offset the front side plate 12f toward the rear side, and faces the front of the housing 5. The right front side plate 12rf is disposed so as to connect the front side plate 12f and the front right side plate 12fr offset from the front side plate 12f, and faces the right side of the housing 5. In the illustrated example, the right front side plate 12rf faces the right side of the housing 5 and is disposed at a slight angle so as to face the front side.

[0024] The inclined portion 13a is closed by a right front inclined plate 13fr. The right front inclined plate 13fr is disposed so as to connect the side plate 12fr on the right side of the front of the stepped portion 13b to the side plate 12 on the right side.

[0025] Joints 16 and 17 that connect the refrigerant piping are arranged on the side plate 12fr on the right side of the front. The joints 16 and 17 are part of the refrigerant piping that circulates the refrigerant through the heat exchanger 3, and connect the refrigerant piping outside the indoor unit 2 to the heat exchanger 3 inside the indoor unit 2. The joints 16 and 17 extend substantially straight toward the front of the housing 5 (hereinafter also referred to as the front), which is a direction parallel to the normal to the side plate 12f on the front side and along the normal to the side plate 12fr on the right side of the front.

[0026] The side of the conditioned room opposite the open bottom surface of the housing 5 is covered with a decorative panel 19. The decorative panel 19 is equipped with an intake grille 21 located in the center of the decorative panel 19 for drawing air in from the conditioned room, and a plurality of outlets 22 located on the outer edge of the decorative panel 19 for blowing air into the conditioned room. The intake grille 21 covers, for example, an annular bell mouth located in the center of the bottom surface of the housing 5, and faces the intake opening of the housing 5. The plurality of outlets 22 face the plurality of outlet openings of the housing 5. Each of the outlets 22 is equipped with a louver for adjusting the air direction.

[0027] The fan is equipped with a fan motor with a rotating shaft extending vertically at approximately the center of the housing 5, and an impeller fixed to the rotating shaft so as to rotate integrally. The fan motor drives the impeller to rotate. The fan motor is fixed to the inner surface of the top plate 11 of the housing 5 via a fastener. The rotating impeller draws air from the conditioned room through the suction opening of the housing 5 via the suction port 21 of the decorative panel 19 and blows the air radially in a direction intersecting the rotation axis. The blown air exchanges heat with the refrigerant flowing in the heat exchanger 3, is blown out through the multiple outlet openings of the housing 5, and is blown into the conditioned room through the outlet 22 of the decorative panel 19. The rotational centerline of the impeller coincides with the rotation axis of the fan motor and extends vertically when the indoor unit 2 is installed.

[0028] The heat exchanger 3 is fixed to the top plate 11 of the housing 5. In this embodiment, the heat exchanger 3 is, for example, a fin-and-tube type, and includes a large number of aligned aluminum alloy fins and refrigerant pipes that pass through the fins.

[0029] The heat exchanger 3 is provided inside the housing 5 and surrounds the radial outside of the fan. The inner peripheral surface of the heat exchanger 3 faces the fan, and the outer peripheral surface of the heat exchanger 3 faces the inner surface of the side plate 12. The heat exchanger 3 has flat plate portions facing each of the side plates 12 of the housing 5 and corner portions connecting two adjacent flat plate portions. For example, there are four flat plate portions and three corner portions.

[0030] Drain pan 6 is located below heat exchanger 3 and receives drain water generated as a result of heat exchange in heat exchanger 3. During cooling operation in which heat exchanger 3 functions as an evaporator, moisture contained in the air passing through heat exchanger 3, i.e., indoor humidity, condenses on the surface of heat exchanger 3 and adheres to heat exchanger 3 as drain water, which drips from heat exchanger 3. Drain pan 6 receives and collects the drain water that drips from heat exchanger 3. The drain water stored in drain pan 6 is pumped by, for example, drain pump 8 (shown in FIG. 5) provided within housing 5, and is discharged to the outside of indoor unit 2 through drain hose 9 (shown in FIG. 5).

[0031] In a plan view, the center of the substantially annular heat exchanger 3, the center of rotation of the fan, the center of the air inlet 21 of the decorative panel 19, and the center of the annular bell mouth are all substantially aligned.

[0032] When the air conditioner 1 is operating in cooling mode, the compressor of the outdoor unit discharges high-temperature, high-pressure gas refrigerant and sends it to the outdoor heat exchanger (condenser). The outdoor heat exchanger exchanges heat between the refrigerant flowing inside it and the outdoor air, condensing the refrigerant. The condensed liquid refrigerant is sent to the indoor unit 2 through the refrigerant piping. The indoor unit 2 expands the liquid refrigerant flowing in from the refrigerant piping using an electric expansion valve, and sends the low-temperature gas-liquid mixed refrigerant to the heat exchanger 3 (evaporator). The heat exchanger 3 exchanges heat between the low-temperature refrigerant flowing inside it and the indoor air, gasifying the refrigerant. During this process, the room is cooled by the low-temperature air blown out from the indoor unit 2.

[0033] When the air conditioner 1 is in heating operation, the compressor of the outdoor unit discharges high-temperature, high-pressure gas refrigerant and sends it to the heat exchanger 3 (condenser) of the indoor unit 2. The heat exchanger 3 exchanges heat between the refrigerant flowing inside and the indoor air, condensing the refrigerant. At this time, the room is heated by the high-temperature air blown out from the indoor unit 2.

[0034] FIG. 4 is an enlarged view of the inclined plate on the left front side of the indoor unit of the air conditioner according to this embodiment.

[0035] As shown in FIG. 4, the housing 5 of the indoor unit 2 according to this embodiment is provided with a drain socket 31 provided on the left front inclined plate 13fl.

[0036] The drain socket 31 extends substantially straight along the normal to the left front inclined plate 13fl. Therefore, the drain socket 31 protrudes in a direction tilted 45 degrees to the left relative to the front of the housing 5. Therefore, the protruding direction of the drain socket 31 is tilted relative to the extension direction of the joint portions 16, 17. The drain socket 31 connects the inside of the housing 5 with the outside of the housing 5, and discharges drain water that accumulates inside the housing 5 and is pumped up by, for example, a drain pump, to the outside of the housing 5.

[0037] Fig. 5 is a schematic diagram showing an enlarged side view of the drain pump and its surroundings provided in the indoor unit of the air conditioner according to this embodiment, and the control unit. The water level of the drain water W in Fig. 5 is the state while the output control described below is being performed (while drain water is flowing back from the drain pump 8).

[0038] As shown in FIG. 5, the indoor unit 2 according to this embodiment includes a drain pan 6, a control unit 4, a drain pump 8, a drain hose 9, and a sterilization unit 10. The control unit 4 controls each part of the air conditioner 1 based on the contents preprogrammed in the microcomputer of the control unit 4 and the contents set prior to operation. The drain pan 6 collects drain water W resulting from heat exchange in the heat exchanger 3. The drain pump 8 pumps up the drain water W collected in the drain pan 6 from an inlet 8a at the bottom. The drain hose 9 discharges the drain water discharged by the drain pump 8 to the outside of the housing 5 via a drain socket 31 and leads it to a drain pipe (not shown) installed in the ceiling of the room to be air-conditioned.

[0039] The sterilization unit 10 sterilizes the drain water W. For example, the sterilization unit 10 is a sterilization unit that irradiates the drain water W with a sterilizing substance and / or an antibacterial agent provided in the drain pan 6. An example in which the sterilization unit 10 is a sterilization unit will be described below. The sterilization unit 10 is disposed in a position where it can irradiate the sterilizing substance toward all or part of the lower region R of the suction port 8a of the drain pump 8, and sterilizes all or part of the drain water W. FIG. 5 shows the irradiation region U of the sterilization substance. It is preferable that the sterilization unit 10 irradiates the sterilizing substance toward a wide range of the drain water, including all or part of the lower region R of the suction port 8a of the drain pump 8, and multiple sterilization units may be provided. Examples of the sterilization unit 10 include an ultraviolet irradiation device that generates and irradiates ultraviolet rays (e.g., deep ultraviolet (UV-C)), an ozone irradiation device that generates and irradiates ozone, a device including a photocatalyst, and a device that combines these sterilization functions.

[0040] Next, the operation of the indoor unit of the air conditioner according to this embodiment will be described using the flowchart shown in FIG.

[0041] Figures 6 and 7 are flow charts showing the operation of the indoor unit of the air conditioner according to this embodiment. In Figures 6 and 7, the reference numerals with a number appended to "S" indicate each step in the flow chart.

[0042] The indoor unit 2 of the air conditioner 1 is equipped with a control unit 4, and operates as follows by controlling each part of the air conditioner 1 based on the contents pre-programmed in the microcomputer of the control unit 4 and the contents set prior to operation.

[0043] First, power is supplied to the main power supply, and the air conditioner 1 enters an operation preparation state. Next, the control unit 4 determines whether or not the user has operated the operation start button of the air conditioner 1 (step S1). If it is determined that the operation start button has been operated, the control unit 4 starts the air conditioning operation of the air conditioner 1.

[0044] Furthermore, the user selects a desired operation mode from (1) cooling operation mode, (2) dehumidification operation mode, (3) fan / humidification operation mode, (4) heating / humidification operation mode, (5) fan operation mode, and (6) heating operation mode, and the air conditioner 1 is set to the desired operation mode (step S2). If the operation mode is one of (1) to (4) above in step S2, the control unit 4 drives the drain pump 8 (step S3) to pump up the drain water accumulated in the drain pan 6 through the suction port 8a. Then, the drain hose 9 discharges the drain water discharged by the drain pump 8 to the outside of the housing 5.

[0045] Next, the control unit 4 determines whether the operating time in any of the above operating modes (1) to (6) has elapsed a predetermined time, and whether the user has operated the operation stop button of the air conditioner 1 (step S4).

[0046] If it is determined in step S4 that the operation time has elapsed for a predetermined time or that the operation stop button has been operated, the air conditioning operation of the air conditioner 1 is stopped. Then, the control unit 4 determines whether the immediately preceding operation mode was one of the above (1) to (4) (step S5).

[0047] If it is determined in step S5 that the immediately preceding operation mode was not any of the above (1) to (4), the control unit 4 performs operation termination processing, and the air conditioner 1 stops and enters a stopped state (step S6).

[0048] On the other hand, if it is determined in step S5 that the previous operating mode was one of the above (1) to (4), the control unit 4 determines whether the post-operation setting of the above (1) to (4) set prior to the start of operation was a setting with a drain pan sterilization operation mode (step S7).

[0049] If it is determined in step S7 that the drain pan sterilization operation mode is not set, the control unit 4 performs an operation termination process, and the air conditioner 1 stops and enters a stopped state (step S6).

[0050] On the other hand, if it is determined in step S7 that the drain pan sterilization operation mode is set, the control unit 4 performs output control to gradually reduce the output of the drain pump 8 from driving to stopping, and controls the sterilization unit 10 to irradiate the sterilizing substance while performing this output control (during the first section in which the drain water is flowing back), thereby sterilizing the drain water (step S8).

[0051] This output control adjusts the flow rate of drain water sucked into the drain pump 8, so that the drain water present in the drain pipe outside the housing 5, the drain hose 9 inside the housing 5, and the drain pump 8 slowly flows out from the suction port 8a of the drain pump 8 into the lower region R. The drain water flowing out from the suction port 8a slowly merges with the drain water W in the drain pan 6. In other words, the drain water flowing out from the suction port 8a slowly passes through the irradiation region U of the sterilization unit 10.

[0052] When the drain pan sterilization operation in step S8 is completed, the control unit 4 performs an operation termination process, and the air conditioner 1 is stopped and put into a stopped state (step S6). In step S6, in any of the above cases (1) to (4), the drain pump 8 that was driven in step S3 is stopped, and the discharge of drain water to the outside of the housing 5 is stopped.

[0053] On the other hand, if it is determined in step S1 that the operation start button has not been operated (proceeding to "A" in Fig. 7), the control unit 4 determines whether the standby time has elapsed a predetermined time (step S9), as shown in Fig. 7. If it is determined that the standby time has elapsed a predetermined time, the control unit 4 determines whether the drain pan sterilization operation mode has been set (step S7').

[0054] If it is determined in step S7' that the drain pan sterilization operation mode is not set (proceed to "B" in FIG. 6), the control unit 4 does nothing and proceeds to the determination in step S1 again.

[0055] On the other hand, if it is determined in step S7' that the drain pan sterilization operation mode is enabled, the control unit 4 performs output control to gradually reduce the output of the drain pump 8 from driving to stopping, and controls the sterilization unit 10 to irradiate the sterilizing substance while the output control is being performed (during the first section in which the drain water is flowing backward), thereby sterilizing the drain water (step S8'). Unlike step S8 (shown in FIG. 6), the output control to gradually reduce the output in step S8' is not dependent on the type of operation mode (1) to (6) immediately before.

[0056] When the drain pan sterilization operation in step S8' is completed (proceeding to "B" in FIG. 6), the control unit 4 again proceeds to the determination in step S1.

[0057] Also, in step S9, if it is not determined that the waiting time has elapsed a predetermined time (proceeding to "B" in FIG. 6), the control unit 4 again proceeds to the determination in step S1.

[0058] The operation of drain pump 8 in step S8 (and also step S8') will be described using Figures 8 and 9. Figure 8 is a diagram for explaining a first method for sterilizing drain water accumulated in a drain pump provided in the indoor unit of the air conditioner according to this embodiment. Figure 9 is a diagram for explaining a second method for sterilizing drain water accumulated in a drain pump provided in the indoor unit of the air conditioner according to this embodiment. Figures 8(A) and 9(A) are diagrams showing the operation of a drain pump according to a comparative example. Figures 8(B) and 9(B) are diagrams showing the operation of drain pump 8 according to this embodiment.

[0059] In the indoor unit of an air conditioner according to a comparative example (hereinafter referred to as air conditioner 1'), the control unit controls the drain pump 8 to turn ON / OFF, as shown in FIG. 8(A). In the air conditioner 1', after an instruction to stop operation is given, the control unit 4' starts a sterilization operation for the drain pan if the immediately preceding mode was one of operation modes (1) to (4). After an instruction to stop operation of the air conditioner 1' is given, the drain pump 8 switches from ON to OFF, causing drain water present in the drain hose 9 and drain pump 8, etc., to flow back under its own weight and flow out of the inlet 8a of the drain pump 8 into the drain pan 6. At this time, a sterilizing substance is applied to the drain water flowing out of the inlet 8a of the stopped drain pump 8 to sterilize the drain water.

[0060] In addition, after a period in which the drain pump 8 is stopped (third period), there is again a period in which the drain pump 8 is turned ON (second period), and then the drain pump 8 is turned OFF, thereby agitating the drain water accumulated in the drain pan 6 of the air conditioner 1' and sterilizing the drain pan 6.

[0061] However, in this case, when the drain pump 8 is switched off, the drain water flows out from the bottom of the drain pump 8 at a high speed, and a single pass of irradiation is not sufficient to achieve a sufficient sterilization effect. When the above-mentioned sterilization operation (sterilization operation using only ON / OFF control of the drain pump 8) was performed, and an anti-biofilm test was conducted on plastic products, etc. by immersing a plastic test piece in the drain water W accumulated in the drain pan 6, a black biofilm formed on the test piece. Microorganisms in the drain water adhered to and multiplied on the surface of the test piece.

[0062] On the other hand, in the indoor unit 2 of the air conditioner 1 according to this embodiment, after issuing an instruction to stop operation in any of the operation modes (1) to (4) above, the control unit 4 does not turn off the drain pump 8, but rather controls the drain pump 8 to turn off after a period (first period) in which the output of the drain pump 8 is gradually reduced. If the drain pump 8 is an AC-powered pump, high-speed switching using duty adjustment is used, while if the drain pump 8 is a DC-powered pump, the applied DC voltage can be adjusted.

[0063] 8(B) , the control unit 4 gradually reduces the output of the drain pump 8 from driven (DUTY 100%) to stopped (DUTY 0%). While the output of the drain pump 8 is gradually reduced, that is, during the first section, drain water present in the drain pipe outside the housing 5, the drain hose 9 inside the housing 5, and the drain pump 8 flows back, but slowly flows out of the suction port 8a of the drain pump 8 into the drain pan 6.

[0064] In addition, after a period in which the drain pump 8 is stopped (third period), a period in which the drain pump 8 is turned ON again (second period) is set, and then a period in which the output of the drain pump 8 is gradually reduced (first period) is set, after which the drain pump 8 is turned OFF, thereby agitating the drain water accumulated in the drain pan 6 of the air conditioner 1 and sterilizing the drain pan 6.

[0065] During the first section, the drain water flows out slowly from the bottom of the drain pump 8, allowing it to pass slowly through the irradiation area U of the sterilization section, thereby effectively sterilizing the drain water. Therefore, a sufficient sterilization effect can be achieved with one pass of irradiation. When the sterilization operation of this embodiment (sterilization operation in which the output of the drain pump 8 is gradually reduced from driving to stopping during the sterilization operation of steps S7 and S7') was performed, an anti-biofilm test on plastic products, etc. was conducted in the same manner as described above using drain water accumulated in the drain pan 6, but no biofilm was formed on the test specimens.

[0066] In the first section of Figure 8(B), the output of the drain pump 8 is decreased in four stages, but this is not limited to this case and the output may be decreased in two or three stages, or in five or more stages. Also, in the first section of Figure 8(B), an example of the duty percentage for each stage is shown, but this is not limited to this case and any duty percentage can be set. Furthermore, in the first section of Figure 8(B), the time width for each stage is the same (all 30 seconds), but this is not limited to this case.

[0067] Although a case where the drain pump 8 is gradually reduced from being driven to being stopped when any of the above (1) to (4) operation stops has been described using Figure 8, the present invention is not limited to this case. For example, as shown in Figure 9(B), the drain pump 8 may be gradually reduced from being driven to being stopped after a predetermined period of time (120 seconds) has elapsed since any of the above (1) to (4) operation stops. In this case, the drain water is also sterilized in the second section from when operation stops until the predetermined period has elapsed, in the same way as in the first section, thereby improving the sterilization effect of the drain water.

[0068] It has been described that sterilization is performed by irradiating the sterilizing substance during the first section (i.e., while output control is being performed to gradually reduce the output of the drain pump 8 from driving to stopping it) after the operation of any of (1) to (4) above has stopped, but the time period for sterilization is not limited to this case. Sterilization by the sterilization unit 10 may be performed not only during the first section, but also during the second and / or third section (e.g., as shown in FIG. 9(B)), or may be performed during any of the operations of (1) to (6) above. Furthermore, it may be performed according to any set time.

[0069] As explained above, the indoor unit 2 of the air conditioner 1 according to this embodiment ensures the contact time of the disinfecting substance with the drain water that flows back due to its own weight when the drain pump 8 is stopped, thereby enhancing the disinfecting effect of the drain water. Furthermore, because the disinfecting effect is enhanced by the indoor unit 2 of the air conditioner according to this embodiment, it is no longer necessary to switch from drive to stop multiple times to ensure the contact time of the disinfecting substance, and therefore the driving noise of the drain pump 8 and the suction noise of the drain water (stirring noise) during this switching can be reduced, minimizing discomfort to users.

[0070] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0071] 1...air conditioner, 2...indoor unit, 3...heat exchanger, 4...control unit, 5...casing, 6...drain pan, 7...blower, 8...drain pump, 9...drain hose, 10...sterilization unit, 11...top plate, 12...side plate, 12f...front side plate, 12fr...front right side plate, 12rf...right front side plate, 13...inclined plate, 13a...inclined portion, 13b...step portion, 13fl...left front inclined plate, 13fr...right front inclined plate, 15...support bracket, 16, 17...joint portion, 19...bottom plate, 21...intake port, 22...outlet, 31...drain socket.

Claims

1. A main unit that can be attached to the ceiling of the room to be air-conditioned, a heat exchanger housed in the main body; a drain pan for collecting drain water resulting from heat exchange in the heat exchanger; a drain pump that pumps up the drain water accumulated in the drain pan; a drain hose that discharges the drain water discharged by the drain pump to the outside of the main body; a sterilization unit that sterilizes the drain water; a control unit that controls the output of the drain pump so as to gradually reduce the output of the drain pump from driving to stopping; An indoor unit of an air conditioner equipped with the same.

2. 2. The indoor unit of the air conditioner according to claim 1, wherein the sterilization unit is arranged at a position where it can irradiate a sterilizing substance toward all or part of a lower region of the suction port of the drain pump, and sterilizes all or part of the drain water.

3. 2. The indoor unit of the air conditioner according to claim 1, wherein the control unit performs the output control by gradually reducing the output of the drain pump from drive to stop when any of the cooling operation mode, the dehumidification operation mode, the fan / humidification operation mode, and the heating / humidification operation mode is completed.

4. 2. The indoor unit of an air conditioner according to claim 1, wherein the control unit performs the output control including a first section of control in which the output of the drain pump is gradually reduced from being driven to being stopped after a predetermined time has elapsed with the air conditioner stopped, and a second section of control in which the drain pump is driven.

5. The indoor unit of an air conditioner according to claim 4 , wherein the control unit controls the output of the drain pump so that the first interval and the second interval have the same time duration.

6. 3. The indoor unit of the air conditioner according to claim 2, wherein the control unit controls the sterilization unit to irradiate the sterilizing substance during a first section of control in which an output of the drain pump is gradually reduced from being driven to being stopped.

7. The indoor unit of an air conditioner according to claim 1 , wherein the sterilization section is a device that irradiates the drain water accumulated in the drain pan with ultraviolet light as a sterilizing substance.

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