阅读说明：本技术 空调机 (Air conditioner ) 是由 田中幸范 吉田和正 于 2018-06-12 设计创作，主要内容包括：本发明提供使室内换热器成为清洁的状态且水难以从接水盘溢出的空调机。空调机具备制冷剂回路和控制部,还具备配置于室内换热器(15)的下侧的接水盘(18)。而且,控制部使室内换热器(15)作为蒸发器发挥功能,进行使室内换热器(15)冻结或者结露的处理,在外部空气温度为第一阈值以下时进行了上述处理的情况下,在从进行该处理起经过预定的禁止期间之前,不开始下次的上述处理。(The invention provides an air conditioner which enables an indoor heat exchanger to be in a clean state and water is difficult to overflow from a water receiving tray. The air conditioner is provided with a refrigerant circuit, a control unit, and a water receiving tray (18) disposed below the indoor heat exchanger (15). The control unit causes the indoor heat exchanger (15) to function as an evaporator, performs a process of freezing or condensing the indoor heat exchanger (15), and does not start the next process until a predetermined prohibition period elapses since the process is performed when the outside air temperature is equal to or lower than the first threshold value.)

1. An air conditioner is characterized by comprising:

a refrigerant circuit for circulating a refrigerant through the compressor, the condenser, the expansion valve, and the evaporator in this order, and

a control unit for controlling at least the compressor and the expansion valve,

one of the condenser and the evaporator is an outdoor heat exchanger, and the other is an indoor heat exchanger,

and a water receiving tray arranged below the indoor heat exchanger,

the control unit causes the indoor heat exchanger to function as the evaporator, performs a process of freezing or condensing the indoor heat exchanger,

when the process is performed when the outside air temperature is equal to or lower than the first threshold value, the process is not started until a predetermined prohibition period elapses after the process is performed.

2. An air conditioner is characterized by comprising:

a refrigerant circuit for circulating a refrigerant through the compressor, the condenser, the expansion valve, and the evaporator in this order, and

a control unit for controlling at least the compressor and the expansion valve,

one of the condenser and the evaporator is an outdoor heat exchanger, and the other is an indoor heat exchanger,

and a water receiving tray arranged below the indoor heat exchanger,

the control unit causes the indoor heat exchanger to function as the evaporator, performs a process of freezing or condensing the indoor heat exchanger,

the operation time of the process is shortened when the process is performed when the outside air temperature is equal to or lower than the first threshold value, as compared with the case when the process is performed when the outside air temperature is higher than the first threshold value.

3. The air conditioner according to claim 1,

the control unit may shorten the length of the prohibition period as the indoor temperature during the processing is higher or the indoor humidity during the processing is lower.

4. The air conditioner according to claim 1,

when a start command for the process is input from a remote controller during the prohibition period, the control unit does not start the process corresponding to the start command.

5. The air conditioner according to claim 1,

when a start command for the process is input from a remote controller during the prohibition period, the control unit starts the process after the prohibition period elapses.

6. The air conditioner according to claim 1,

when a start command for the process is input from a remote controller during the prohibition period, and when the outside air temperature at the time of the input of the start command is equal to or higher than a second threshold value that is higher than the first threshold value, the control unit shortens the length of the prohibition period or starts the process in accordance with the start command.

7. The air conditioner according to claim 2,

when the outside air temperature is equal to or lower than the first threshold value and the elapsed time from the end of the previous process to the start of the current process is equal to or lower than a predetermined time, the control unit makes the operation time of the current process shorter than that of the previous process.

8. An air conditioner according to claim 1 or 2,

the outside air temperature being equal to or lower than the first threshold value means that the outside air temperature is equal to or lower than the freezing point.

9. An air conditioner according to claim 1 or 2,

when the process is performed when the outside air temperature is equal to or lower than the first threshold value, the control unit performs a heating operation or an air blowing operation after the process.

10. The air conditioner according to claim 1,

when the processing is performed when the outside air temperature is equal to or lower than the first threshold value, the control unit shortens the length of the prohibition period when the heating operation or the blowing operation is performed as the air conditioning operation corresponding to the operation of the remote controller during the prohibition period after the processing.

11. The air conditioner according to claim 1,

the control unit extends the prohibition period when the outside air temperature during the passage of the prohibition period is equal to or less than the first threshold value.

Technical Field

The present invention relates to an air conditioner.

Background

As a technique for bringing an indoor heat exchanger of an air conditioner into a clean state, for example, patent document 1 describes the following technique: the indoor heat exchanger is sequentially frosted and defrosted to remove dirt of the indoor heat exchanger.

Disclosure of Invention

Problems to be solved by the invention

However, the condensed water in the indoor heat exchanger flows down the drain pan and is discharged to the outside through the drain pipe. However, when the drain pipe is clogged for some reason, the water in the drain pan is not discharged to the outside, and the water may overflow from the drain pan. Patent document 1 does not describe a countermeasure to such a problem.

Therefore, an object of the present invention is to provide an air conditioner in which an indoor heat exchanger is kept clean and water is less likely to overflow from a drain pan.

Means for solving the problems

In order to solve the above problem, the air conditioner according to the present invention is characterized in that the control unit causes the indoor heat exchanger to function as an evaporator, performs a process of freezing or condensing the indoor heat exchanger, and does not start the next process until a predetermined prohibition period elapses since the process is performed when the outside air temperature is equal to or lower than the first threshold value.

Further, the air conditioner of the present invention is characterized in that the control unit causes the indoor heat exchanger to function as an evaporator, performs a process of freezing or condensing the indoor heat exchanger, and shortens an operation time of the process when the process is performed when the outside air temperature is equal to or lower than the first threshold value, as compared with a case when the process is performed when the outside air temperature is higher than the first threshold value.

The effects of the invention are as follows.

According to the present invention, it is possible to provide an air conditioner in which an indoor heat exchanger is kept clean and water is less likely to overflow from a water receiving tray.

Drawings

Fig. 1 is a configuration diagram of an air conditioner according to a first embodiment of the present invention.

Fig. 2 is a longitudinal sectional view of an indoor unit of an air conditioner according to a first embodiment of the present invention.

Fig. 3 is a functional block diagram of an air conditioner according to a first embodiment of the present invention.

Fig. 4 is a flowchart of a process for freeze-washing an indoor heat exchanger provided in an air conditioner according to a first embodiment of the present invention.

Fig. 5 is an explanatory diagram showing a state during defrosting of an indoor heat exchanger provided in an air conditioner according to a first embodiment of the present invention.

Fig. 6 is a flowchart of a process executed by the control unit of the air conditioner according to the first embodiment of the present invention.

Fig. 7 is a flowchart of a process executed by the control unit of the air conditioner according to the second embodiment of the present invention.

Detailed Description

First embodiment

Structure of air conditioner

Fig. 1 is a configuration diagram of an air conditioner 100 according to a first embodiment.

Note that solid arrows in fig. 1 show the flow of the refrigerant during the heating operation.

On the other hand, the dashed arrows in fig. 1 show the flow of the refrigerant during the cooling operation.

The air conditioner 100 is a device that performs air conditioning such as a heating operation and a cooling operation. As shown in fig. 1, the air conditioner 100 includes a compressor 11, an outdoor heat exchanger 12, an outdoor fan 13, and an expansion valve 14. In addition to the above configuration, the air conditioner 100 includes an indoor heat exchanger 15, an indoor fan 16, and a four-way valve 17.

The compressor 11 is a device that compresses a low-temperature low-pressure gas refrigerant and discharges the refrigerant as a high-temperature high-pressure gas refrigerant. As shown in fig. 1, the compressor 11 includes a compressor motor 11a as a drive source.

The outdoor heat exchanger 12 exchanges heat between the refrigerant flowing through the heat transfer pipe (not shown) and the outside air sent from the outdoor fan 13.

The outdoor fan 13 is a fan that sends outside air to the outdoor heat exchanger 12. The outdoor fan 13 includes an outdoor fan motor 13a as a drive source, and is disposed in the vicinity of the outdoor heat exchanger 12.

The expansion valve 14 is a valve that reduces the pressure of the refrigerant condensed by the "condenser" (one of the outdoor heat exchanger 12 and the indoor heat exchanger 15). The refrigerant decompressed by the expansion valve 14 is guided to the "evaporator" (the other of the outdoor heat exchanger 12 and the indoor heat exchanger 15).

The indoor heat exchanger 15 exchanges heat between the refrigerant flowing through the heat transfer pipe g (see fig. 2) and the indoor air (air in the space to be air-conditioned) sent from the indoor fan 16.

The indoor fan 16 is a fan that sends indoor air to the indoor heat exchanger 15. The indoor fan 16 includes an indoor fan motor 16c (see fig. 3) as a drive source, and is disposed in the vicinity of the indoor heat exchanger 15.

The four-way valve 17 is a valve for switching the flow path of the refrigerant according to the operation mode of the air conditioner 100. For example, during a cooling operation (see a dotted arrow in fig. 1), in the refrigerant circuit Q, the refrigerant circulates through the refrigeration cycle via the compressor 11, the outdoor heat exchanger 12 (condenser), the expansion valve 14, and the indoor heat exchanger 15 (evaporator) in this order.

On the other hand, during the heating operation (see solid arrows in fig. 1), the refrigerant circulates through the refrigeration cycle in the refrigerant circuit Q via the compressor 11, the indoor heat exchanger 15 (condenser), the expansion valve 14, and the outdoor heat exchanger 12 (evaporator) in this order.

That is, in the refrigerant circuit Q in which the refrigerant circulates through the compressor 11, the "condenser", the expansion valve 14, and the "evaporator" in this order, one of the "condenser" and the "evaporator" is the outdoor heat exchanger 12, and the other is the indoor heat exchanger 15.

In the example shown in fig. 1, a compressor 11, an outdoor heat exchanger 12, an outdoor fan 13, an expansion valve 14, and a four-way valve 17 are provided in the outdoor unit Uo. On the other hand, the indoor heat exchanger 15 and the indoor fan 16 are provided in the indoor unit Ui.

Fig. 2 is a longitudinal sectional view of the indoor unit Ui.

As shown in fig. 2, the indoor unit Ui includes, in addition to the indoor heat exchanger 15 and the indoor fan 16, a water pan 18 (also referred to as a leak pan), a casing base 19, and filters 20a and 20 b. The indoor unit Ui includes a front panel 21, a horizontal air vane 22, and a vertical air vane 23.

The indoor heat exchanger 15 includes a plurality of fins f and a plurality of heat transfer pipes g penetrating the fins f. In addition, from another viewpoint, the indoor heat exchanger 15 includes a front indoor heat exchanger 15a disposed on the front side of the indoor fan 16 and a rear indoor heat exchanger 15b disposed on the rear side of the indoor fan 16. In the example shown in fig. 2, the upper end of the front indoor heat exchanger 15a and the upper end of the rear indoor heat exchanger 15b are connected in an inverted V shape.

The indoor fan 16 is, for example, a cylindrical cross flow fan, and is disposed in the vicinity of the indoor heat exchanger 15. The indoor fan 16 includes a plurality of fan blades 16a, a partition plate 16b on which the fan blades 16a are provided, and an indoor fan motor 16c (see fig. 3) as a drive source.

The water receiving tray 18 receives the condensed water of the indoor heat exchanger 15, and is disposed below the indoor heat exchanger 15.

The casing base 19 is a casing for installing the indoor heat exchanger 15, the indoor fan 16, and the like.

The filters 20a and 20b collect dust from the air flowing toward the indoor heat exchanger 15 in response to the driving of the indoor fan 16. One filter 20a is disposed on the front side of the indoor heat exchanger 15, and the other filter 20b is disposed on the upper side of the indoor heat exchanger 15.

The front panel 21 is a panel provided to cover the front filter 20a, and is rotatable toward the front with the lower end as an axis. The front panel 21 may not rotate.

The horizontal air vanes 22 are plate-like members that adjust the direction of air blown into the room in the horizontal direction. The horizontal air vanes 22 are disposed in the outlet air duct h3, and are rotated in the horizontal direction by the horizontal air vane motor 24 (see fig. 3).

The up-down wind direction plate 23 is a plate-like member that adjusts the wind direction of the air blown into the room in the up-down direction. The up-down wind direction plate 23 is disposed in the vicinity of the air outlet h4, and is rotated in the up-down direction by the up-down wind direction plate motor 25 (see fig. 3).

The air sucked in through the air suction ports h1 and h2 exchanges heat with the refrigerant flowing through the heat transfer tubes g of the indoor heat exchanger 15, and is guided to the outlet air passage h 3. The air flowing through the outlet duct h3 is guided in a predetermined direction by the horizontal wind direction plate 22 and the vertical wind direction plate 23, and is blown out into the room through the air outlet h 4.

Most of the dust directed toward the air inlets h1, h2 with the air flow is collected by the filters 20a, 20 b. However, there are cases where fine dust passes through the filters 20a and 20b and adheres to the indoor heat exchanger 15, and it is desirable to periodically clean the indoor heat exchanger 15. Therefore, in the present embodiment, after frost has formed due to freezing in the indoor heat exchanger 15, the indoor heat exchanger 15 is defrosted and cleaned. Hereinafter, a series of processes including frosting and thawing of the indoor heat exchanger 15 will be referred to as "freeze cleaning" of the indoor heat exchanger 15.

Fig. 3 is a functional block diagram of the air conditioner 100.

In addition to the above-described configurations, the indoor unit Ui shown in fig. 3 includes a remote controller transmitting/receiving unit 26, an environment detection unit 27, and an indoor control circuit 31.

The remote controller transceiver 26 exchanges predetermined information with the remote controller 40 by infrared communication or the like.

The environment detection unit 27 includes an indoor temperature sensor 27a, a humidity sensor 27b, and an indoor heat exchanger temperature sensor 27 c.

The indoor temperature sensor 27a is a sensor for detecting the temperature of the room (air-conditioned space), and is provided on the air intake side of the filters 20a and 20b (see fig. 2), for example.

The humidity sensor 27b is a sensor for detecting the humidity of the indoor air, and is provided at a predetermined position of the indoor unit Ui.

The indoor heat exchanger temperature sensor 27c is a sensor for detecting the temperature of the indoor heat exchanger 15 (see fig. 2), and is provided in the indoor heat exchanger 15.

The detection values of the indoor temperature sensor 27a, the humidity sensor 27b, and the indoor heat exchanger temperature sensor 27c are output to the indoor control circuit 31.

Although not shown, the indoor control circuit 31 is configured as an electronic circuit including a cpu (central Processing unit), a rom (read Only memory), a ram (random Access memory), various interfaces, and the like. Further, a program stored in the ROM is read and developed in the RAM, so that the CPU executes various processes.

As shown in fig. 3, the indoor control circuit 31 includes a storage unit 31a and an indoor control unit 31 b.

In addition to the predetermined program, the storage unit 31a stores data received via the remote controller transmitting/receiving unit 26, detection values of the sensors, and the like.

The indoor control unit 31b controls the indoor fan motor 16c, the horizontal louver motor 24, the vertical louver motor 25, and the like based on the data stored in the storage unit 31 a.

In addition to the above configuration, the outdoor unit Uo includes an outdoor temperature sensor 28 and an outdoor control circuit 32.

The outdoor temperature sensor 28 is a sensor for detecting the outdoor temperature, and is provided at a predetermined position of the outdoor unit Uo (see fig. 1). The outdoor unit Uo further includes a plurality of sensors for detecting a suction temperature, a discharge pressure, and the like of the compressor 11 (see fig. 1), but these sensors are not shown in fig. 3. The detection values of the respective sensors including the outdoor temperature sensor 28 are output to the outdoor control circuit 32.

Although not shown, the outdoor control circuit 32 is configured as an electronic circuit including a CPU, a ROM, a RAM, various interfaces, and the like, and is connected to the indoor control circuit 31 via a communication line. As shown in fig. 3, the outdoor control circuit 32 includes a storage unit 32a and an outdoor control unit 32 b.

In addition to a predetermined program, the storage unit 32a stores data and the like received from the indoor control circuit 31. The outdoor control unit 32b controls the compressor motor 11a, the outdoor fan motor 13a, the expansion valve 14, and the like based on the data stored in the storage unit 32 a. Hereinafter, the indoor control circuit 31 and the outdoor control circuit 32 are collectively referred to as "control unit 30".

Next, the process of the control unit 30 for freeze cleaning of the indoor heat exchanger 15 will be described with reference to fig. 4.

Processing of control section

Fig. 4 is a flowchart of the process of freeze cleaning of the indoor heat exchanger 15 (see fig. 2 and 3 as appropriate).

In step S101 of fig. 4, the control unit 30 freezes the indoor heat exchanger 15. That is, the control unit 30 causes the indoor heat exchanger 15 to function as an evaporator, and causes the indoor heat exchanger 15 to freeze by frosting moisture in the air on the indoor heat exchanger 15.

To describe step S101 in more detail, the controller 30 drives the compressor 11 (see fig. 1) and reduces the opening degree of the expansion valve 14 (see fig. 1) to be smaller than that in the cooling operation. As a result, the refrigerant having a low pressure and a low evaporation temperature flows into the indoor heat exchanger 15, and moisture in the air is frozen in the indoor heat exchanger 15, and the frost and ice (symbol i shown in fig. 5) tend to grow.

Next, in step S102, the control unit 30 defrosts the indoor heat exchanger 15.

Fig. 5 is an explanatory diagram showing a state during defrosting of the indoor heat exchanger 15.

After freezing of the indoor heat exchanger 15, the control unit 30 stops the devices such as the indoor fan 16 and the compressor 11 (see fig. 1). As a result, frost and ice (symbol i shown in fig. 5) in the indoor heat exchanger 15 naturally thaw at room temperature, and a large amount of water w flows along the fins f and flows down the water collector 18. This washes out dust j adhering to the indoor heat exchanger 15.

After the indoor heat exchanger 15 is frozen or thawed (S101 and S102 in fig. 4), the control unit 30 may perform a heating operation or an air blowing operation to dry the inside of the indoor unit Ui. This can suppress the growth of bacteria such as mold in the indoor unit Ui.

However, if the outside air temperature is too low (for example, below freezing point), a drain pipe (not shown) freezes, and water may not flow. In the conventional technology, if the drain pipe is clogged as described above, water generated during defrosting of the indoor heat exchanger 15 may overflow from the drain pan 18.

In consideration of this, for example, it is considered that the control unit 30 continuously prohibits the freeze washing of the indoor heat exchanger 15 even while the outside air temperature is not higher than the freezing point. However, if the prohibition time of freeze cleaning is too long, dirt accumulates in the indoor heat exchanger 15, and the efficiency of the air conditioning operation may be reduced, and bacteria may grow. Therefore, in the present embodiment, even if the outside air temperature is equal to or lower than the predetermined temperature (first threshold value), freeze cleaning is performed, and the next freeze cleaning is prohibited until the subsequent prohibition period elapses.

Fig. 6 is a flowchart of processing executed by the control section 30 (refer to fig. 3 as appropriate).

Note that the air conditioning operation is not performed at the time of "START (START)" in fig. 6.

In step S201, control unit 30 determines whether or not a predetermined cleaning condition is satisfied. The "cleaning condition" is, for example, a condition in which a value obtained by integrating the execution time of the air conditioning operation from the end of the previous freeze cleaning reaches a predetermined value.

If the predetermined cleaning condition is satisfied in step S201 (yes in S201), the process of control unit 30 proceeds to step S202. On the other hand, if the predetermined cleaning condition is not satisfied (no in S201), control unit 30 repeats the process of step S201.

In step S202, control unit 30 determines whether or not the outside air temperature detected by outdoor temperature sensor 28 (see fig. 3) is equal to or lower than a first threshold value. The "first threshold" is a threshold that is a criterion for determining whether or not the freeze washing prohibition period (S204) is set, and is set in advance. For example, in step S202, the control unit 30 determines whether or not the outside air temperature is below the freezing point (whether or not there is a possibility that a drain pipe, not shown, is clogged due to freezing or the like).

If the outside air temperature is equal to or lower than the first threshold value in step S202 (yes in S202), control unit 30 performs freeze cleaning in step S203. That is, the control unit 30 causes the indoor heat exchanger 15 to function as an evaporator, and performs a process such as freezing the indoor heat exchanger 15 (see fig. 4 and 5).

After the freeze-washing is performed in step S203, the control unit 30 sets a predetermined prohibition period in step S204. The prohibition period is a period for prohibiting freeze cleaning of the indoor heat exchanger 15, and the length thereof is set in advance.

For example, when the control unit 30 performs freeze cleaning (freezing and thawing) of the indoor heat exchanger 15 in a state where the drain pipe (not shown) is frozen and water does not flow, water flowing down from the indoor heat exchanger 15 is accumulated in the water receiving tray 18. The length of the freeze-washing prohibition period is set in advance as a period (for example, several tens of hours) before most of the water accumulated in the drain pan 18 evaporates by natural convection or the like.

In a state where the drain pipe (not shown) is frozen and water does not flow, the capacity of the water receiving tray 18 is set appropriately in the design stage so that water does not overflow from the water receiving tray 18 even if the indoor heat exchanger 15 is once frozen and cleaned.

After the freeze purge prohibition period is set in step S204 of fig. 6, the control unit 30 prohibits freeze purging of the indoor heat exchanger 15 in step S205.

Next, in step S206, the control unit 30 determines whether or not a predetermined prohibition period has elapsed since the end of the freeze cleaning in step S203. If the prohibition period has not elapsed (yes in S206), the control unit 30 returns the process to step S205. That is, until the predetermined prohibition period elapses, the control section 30 prohibits the next freeze washing. This prevents freezing and washing from being performed several times in a short time in a state where the drain pipe (not shown) is frozen and clogged, and further prevents water from overflowing from the drain pan 18.

When the prohibition period has elapsed in step S206 (yes in S206), the control unit 30 RETURNs the process to "start" (RETURN)). When the prohibition period has elapsed, most of the water in the drip tray 18 evaporates, and there is no particular problem even if freeze washing is performed again thereafter. That is, even if the drain pipe (not shown) is frozen and water does not flow, and the water is accumulated in the drain tray 18 after freezing and washing, most of the water is evaporated by natural convection or the like when the prohibition period elapses.

If the outside air temperature is higher than the first threshold value in step S202 (S202: no), the process of the control unit 30 proceeds to step S207.

In step S207, the control unit 30 performs freeze cleaning of the indoor heat exchanger 15 as usual (see fig. 4 and 5). After the process of step S207 is performed, the process of the control unit 30 returns to the "start" (return).

Effect

According to the first embodiment, when the control unit 30 performs the freeze washing process when the outside air temperature is equal to or lower than the first threshold value (yes in S202 of fig. 6, S203), the next freeze washing is not started until a predetermined prohibition period elapses from the time of performing the freeze washing (no in S205 and S206). Thus, for example, even in a situation where the drain pipe (not shown) is frozen and water does not flow, the indoor heat exchanger 15 can be brought into a clean state because freeze washing is performed.

In the prohibition period, freeze cleaning of the indoor heat exchanger 15 is prohibited (no in S205 and S206 of fig. 6), and multiple freeze cleaning can be prevented from being performed in a short time. Therefore, water generated by freeze washing can be prevented from overflowing from the drain pan 18.

Second embodiment

The second embodiment is different from the first embodiment in the following respects: when the outside air temperature is equal to or lower than the first threshold value and the elapsed time from the previous freeze washing is short, the control unit 30 makes the freeze time of the indoor heat exchanger 15 shorter than the previous time. Other points (the structure of the air conditioner 100, etc.) are the same as those of the first embodiment. Therefore, portions different from those of the first embodiment will be described, and description of overlapping portions will be omitted.

Fig. 7 is a flowchart of processing executed by the control unit 30 of the air conditioner according to the second embodiment (see fig. 3 as appropriate).

Note that the air conditioning operation is not performed at the "start" time in fig. 7. Steps S301 and S302 are the same as steps S201 and S202 (see fig. 6) of the first embodiment, and therefore, the description thereof is omitted.

If the outside air temperature is equal to or lower than the first threshold value in step S302 of fig. 7 (yes in S302), the process of the control unit 30 proceeds to step S303.

In step S303, the control unit 30 determines whether or not the elapsed time from the previous freeze cleaning is equal to or less than a predetermined time. More specifically, in step S303, the control unit 30 determines whether or not an elapsed time from the end of the previous freeze cleaning to the start of the current freeze cleaning is equal to or less than a predetermined time. The "predetermined time" is a threshold value that is a criterion for determining whether or not the current freezing time is shorter than the previous freezing time (S304), and is set in advance.

If the elapsed time from the previous freeze cleaning is equal to or less than the predetermined time in step S303 (yes in S303), the process of the control unit 30 proceeds to step S304.

In step S304, the control unit 30 makes the current freezing time (the duration of the control for setting the temperature of the indoor heat exchanger 15 shown in fig. 3 to a predetermined value or less) shorter than the previous freezing time. That is, the control unit 30 shortens the operation time of the freeze cleaning as compared with the case where the freeze cleaning is performed when the outside air temperature is higher than the first threshold value (for example, at the time of the previous freeze cleaning).

Further, when the outside air temperature is equal to or lower than the first threshold value (yes in S302) and the elapsed time from the previous freeze-rinsing is equal to or lower than the predetermined time (yes in S303), there is a high possibility that the water generated in the previous freeze-rinsing is not completely evaporated and remains stored in the drain pan 18 (see FIG. 5).

Therefore, in the present embodiment, the control unit 30 makes the current freezing time of the indoor heat exchanger 15 shorter than the previous freezing time (S304). Thus, the amount of frost and ice adhering to the indoor heat exchanger 15 is smaller than that in the previous freeze washing. Therefore, the amount of water flowing down from the indoor heat exchanger 15 to the water receiving tray 18 during the subsequent defrosting is smaller than that during the previous freezing and washing, and water can be prevented from overflowing from the water receiving tray 18.

The length of the freezing time (freezing time shorter than the previous freezing and washing time) in step S304 is set in advance so that water does not overflow from the water receiving tray 18 even if freezing and washing are repeated for a short period of time.

Next, in step S305 of fig. 7, the control unit 30 executes freeze cleaning of the indoor heat exchanger 15 based on the freeze time set in step S304. After the process of step S305 is performed, the process of the control unit 30 returns to the "start" (return).

If the outside air temperature is higher than the first threshold value in step S302 (no in S302), the control unit 30 performs freeze cleaning of the indoor heat exchanger 15 based on the normal freeze time in step S306. This is because even if a large amount of frost or ice adheres to the indoor heat exchanger 15, water can be discharged through a drain pipe (not shown).

If the elapsed time from the previous freeze cleaning is longer than the predetermined time in step S303 (no in S303), the process of the control unit 30 also proceeds to step S306. This is because, when the "predetermined time" described above has elapsed, most of the water stored in the drip tray 18 is likely to evaporate. That is, even if the drain pipe (not shown) is frozen and water does not flow, and water is accumulated in the drain tray 18 after the previous freeze-washing, most of the water is evaporated by natural convection or the like when the elapsed time from the previous freeze-washing is longer than the predetermined time (S303: no). Therefore, there is no particular problem even if the control unit 30 performs freeze cleaning as usual in step S306. After the process of step S306 is performed, the process of the control unit 30 returns to the "start" (return).

Effect

According to the second embodiment, when the outside air temperature is equal to or lower than the first threshold value (yes in S302) and the elapsed time from the end of the previous freeze cleaning (processing) to the start of the current freeze cleaning is equal to or lower than the predetermined time (yes in S303), the control unit 30 makes the operation time of the current freeze cleaning shorter than that of the previous freeze cleaning (S304). Thus, for example, even in a situation where the drain pipe (not shown) is frozen and water does not flow, the indoor heat exchanger 15 can be brought into a clean state because freeze washing is performed.

Further, the control unit 30 can prevent the water generated by the freeze washing from overflowing from the drain pan 18 by setting the operation time of the freeze washing at this time shorter than that of the previous time (S304).

Modifications of the examples

While the air conditioner 100 of the present invention has been described in the embodiments, the present invention is not limited to these descriptions, and various modifications are possible.

For example, instead of freezing or thawing the indoor heat exchanger 15, the control unit 30 may cause the indoor heat exchanger 15 to function as an evaporator to cause condensation on the indoor heat exchanger 15. For example, the control unit 30 adjusts the opening degree of the expansion valve 14 so that the temperature of the indoor heat exchanger 15 is equal to or lower than the dew point of the indoor air and higher than a predetermined freezing temperature (the temperature at which the indoor heat exchanger 15 starts freezing). This causes dew condensation in the indoor heat exchanger 15, and the dew condensation water flushes the indoor heat exchanger 15.

In addition to the first embodiment, in the second embodiment, the control unit 30 may perform a process (also referred to as "freeze cleaning or the like") of causing the indoor heat exchanger 15 to function as an evaporator and causing the indoor heat exchanger 15 to freeze or condense dew. In such a configuration, it is possible to provide the air conditioner 100 in which the indoor heat exchanger 15 is kept clean and water is less likely to overflow from the drain pan 18.

In the first embodiment, the process (S204) in which the control unit 30 sets the prohibition period of the next freeze washing based on the outside air temperature (S202) at the start of the freeze washing (S203 in fig. 6) has been described, but the present invention is not limited to this. For example, the control unit 30 may set a predetermined prohibition period based on the outside air temperature at a predetermined timing when freeze cleaning or the like is performed. Further, the control unit 30 may set a predetermined prohibition period based on the outside air temperature at the end of freeze washing or the like. That is, the control unit 30 may set the prohibition period of the next freeze washing based on the outside air temperature during the freeze washing.

In the first embodiment, the description has been given of the case where the length of the freeze purge prohibition period (S204 in fig. 6) is a fixed value, but the length is not limited to this. For example, the control unit 30 may shorten the length of the prohibition period of freeze washing or the like as the indoor temperature in the process of freeze washing or the like becomes higher or as the indoor humidity (relative humidity or absolute humidity) in the process of freeze washing or the like becomes lower. This is because the higher the indoor temperature and the lower the indoor humidity are, the more easily the water stored in the drip tray 18 evaporates.

In the second embodiment, when the control unit 30 makes the current freezing time of the indoor heat exchanger 15 shorter than the previous freezing time (S304 in fig. 7), the current freezing time may be set as follows. That is, the control unit 30 may shorten the freezing time (the operation time of the freeze washing or the like) as the indoor temperature in the process of the freeze washing or the like is higher or the indoor humidity in the process of the freeze washing or the like is lower. Further, the control unit 30 may shorten the freezing time of the current time as the elapsed time from the end of the previous freezing cleaning to the start of the current freezing cleaning becomes shorter. This makes it possible to appropriately set the length of the freezing time when the freeze washing is performed.

In the first embodiment, the process of the control unit 30 determining whether or not the predetermined cleaning condition is satisfied (S201) after the elapse of the freeze cleaning prohibition period (yes in S206 of fig. 6) has been described, but the present invention is not limited to this. For example, after the freeze washing prohibition period is set, the control unit 30 may repeat the determination as to whether or not the predetermined washing condition is satisfied, and even when the washing condition is satisfied, the control unit 30 may prohibit the freeze washing within the prohibition period.

In the first embodiment, the control unit 30 appropriately performs the freeze cleaning (S203, S207) of the indoor heat exchanger 15 when the predetermined cleaning condition is satisfied (yes in S201 in fig. 6), but the present invention is not limited thereto. That is, when a start command such as freeze cleaning is input from the remote controller 40 (see fig. 3), the control unit 30 may start freeze cleaning of the indoor heat exchanger 15.

When a start command for freeze cleaning or the like is input from the remote controller 40 (see fig. 3) during the prohibition period for freeze cleaning or the like, the control unit 30 preferably does not start freeze cleaning or the like in accordance with the start command. In this case, it may be notified by voice or image that freeze washing or the like is not started. This can prevent water from overflowing from the drain pan 18, and can notify the user that freeze washing or the like is not started.

Further, when a start instruction for freeze cleaning or the like is input from the remote controller 40 (see fig. 3) during the prohibition period for freeze cleaning or the like, the control unit 30 may start freeze cleaning or the like after the prohibition period elapses. This prevents water from overflowing from the drip tray 18, and allows freeze washing or the like to be performed in response to a start command from the remote controller 40.

When a start command for freeze cleaning or the like is input from the remote controller 40 (see fig. 3) during the prohibition period for freeze cleaning or the like, the control unit 30 may shorten the length of the prohibition period or may perform freeze cleaning or the like in response to the start command when the outside air temperature at the time of input of the start command is equal to or higher than a second threshold value that is higher than the first threshold value. The second threshold is, for example, a temperature threshold higher than 0 ℃, and is set in advance. That is, if the water can be discharged through a drain pipe (not shown) in accordance with the rise in the outside air temperature, the control unit 30 may perform freeze cleaning or the like in accordance with a start command from the remote controller 40. This can prevent the prohibition period from continuing unnecessarily for a long time, and the controller 30 can quickly start the next freeze washing.

In the second embodiment, the process (S304) in which the control unit 30 makes the current freezing time shorter than the previous freezing time based on the outside air temperature (S302 in fig. 7) and the elapsed time from the previous freezing cleaning (S303) is described, but the present invention is not limited thereto. For example, the determination process in step S303 may be omitted. That is, the operation time for freeze cleaning or the like may be shortened in the case where the control unit 30 performs the process such as freeze cleaning or the like when the outside air temperature is equal to or lower than the first threshold value, as compared with the case where freeze cleaning or the like is performed when the outside air temperature is higher than the first threshold value.

The processing for the heating operation and the air blowing operation described below may be added to the processing described in the first embodiment (see fig. 6). That is, when the control unit 30 performs freeze cleaning or the like when the outside air temperature is equal to or lower than the first threshold value, the heating operation or the blowing operation may be performed after the freeze cleaning or the like. This is because water stored in the water receiving tray 18 is easily evaporated by performing the heating operation or the air blowing operation. Further, the control unit 30 may perform one of the heating operation and the blowing operation after the freeze washing, and then perform the other. This also applies to the second embodiment.

In the first embodiment, the control unit 30 may perform the following processing. That is, when the freeze cleaning or the like is performed when the outside air temperature is equal to or lower than the first threshold value, the control unit 30 shortens the length of the prohibition period when the heating operation or the blowing operation is performed as the air conditioning operation corresponding to the operation of the remote controller 40 in the prohibition period after the freeze cleaning or the like. This is because water stored in the water receiving tray 18 is easily evaporated by performing the heating operation or the air blowing operation.

In addition, in the prohibition period after the freeze washing or the like, when the heating operation or the blowing operation is performed as the air-conditioning operation corresponding to the operation of the remote controller 40, the length of the prohibition period may be shortened by the control unit 30 as the cumulative time of the air-conditioning operation in the prohibition period increases. This can suppress the prohibition period from continuing unnecessarily for a long time even after the water stored in the drip tray 18 has completely evaporated.

Further, when the outside air temperature when the prohibition period of freeze washing or the like has elapsed is equal to or lower than the first threshold value, the control unit 30 may extend the prohibition period. This can reliably prevent water generated by freeze washing or the like from overflowing from the drain pan 18.

In the first embodiment, the process (S204) in which the control unit 30 sets the freeze washing prohibition period based on the detected value of the outside air temperature (S202 in fig. 6) has been described, but the present invention is not limited to this. For example, the control unit 30 may set the freeze purge prohibition period when the indoor temperature is equal to or lower than the first threshold value when the air conditioning operation is not performed. The length of the prohibition period may be shortened by the control unit 30 as the indoor temperature is higher and the indoor humidity is lower. Accordingly, even in a configuration in which the outdoor temperature sensor 28 (see fig. 3) is not provided, the prohibition period of freeze washing or the like can be appropriately set.

In the first and second embodiments, the case where the outside air temperature is equal to or lower than the freezing point has been described as an example of the condition where the outside air temperature is equal to or lower than the first threshold value, but the present invention is not limited to this. For example, a predetermined value (e.g., 5 ℃) higher than 0 ℃ may be set as the first threshold in consideration of the possibility that water in a drain pipe (not shown) may freeze later.

The first and second embodiments may be combined as appropriate. For example, when the outside air temperature is equal to or lower than the first threshold value (yes in S202 of fig. 6), the control unit 30 may perform freeze cleaning (S203), and after a predetermined prohibition period has elapsed, may make the operation time of the next freeze cleaning shorter than the previous time.

In each of the embodiments, the indoor unit Ui (see fig. 1) and the outdoor unit Uo (see fig. 1) are each provided with one unit, but the present invention is not limited to this. That is, a plurality of indoor units connected in parallel may be provided, and a plurality of outdoor units connected in parallel may be provided.

Further, the embodiments can be applied to various air conditioners other than the wall-mounted air conditioner 100.

The embodiments are described in detail to explain the present invention easily and understandably, and are not limited to having all the configurations described. Further, a part of the configuration of each embodiment can be added, deleted, or replaced with another configuration.

The mechanism and structure described above are not limited to all the mechanisms and structures described in the product, but are shown as necessary for the description.

Description of the symbols

100-air conditioner, 11-compressor, 12-outdoor heat exchanger (condenser/evaporator), 13-outdoor fan, 14-expansion valve, 15-indoor heat exchanger (evaporator/condenser), 16-indoor fan, 17-four-way valve, 18-water pan, 19-cabinet base, 27-environment detecting part, 27 a-indoor temperature sensor, 27 b-humidity sensor, 27 c-indoor heat exchanger temperature sensor, 28-outdoor temperature sensor, 30-control part, 40-remote controller, Q-refrigerant circuit, Uo-outdoor unit, Ui-indoor unit.