JP2019215149A - Air conditioner - Google Patents

Abstract

To provide an air conditioner which brings an indoor heat exchanger into a clean state and makes water less likely to overflow from a drain pan.SOLUTION: An air conditioner includes a refrigerant circuit and a control part and includes a drain pan 18 disposed below the indoor heat exchanger 15. The control part causes the indoor heat exchanger 15 to function as an evaporator to perform processing for freezing the indoor heat exchanger 15 or building up condensation in the indoor heat exchanger 15. If the processing is performed when an outer air temperature is a first threshold value or lower, an operation time of the processing is set short, compared to a case where the processing is performed when the outer air temperature is higher than the first threshold value.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an air conditioner.

  As a technique for keeping an indoor heat exchanger of an air conditioner in a clean state, for example, in Patent Document 1, frosting and defrosting of an indoor heat exchanger are sequentially performed to remove dirt from the indoor heat exchanger. It is described.

JP 2010-14288 A

  By the way, the condensed water in the indoor heat exchanger flows down to the drain pan and is discharged outside via the drain hose. However, when the drain hose is clogged for some reason, the water in the drain pan is not discharged to the outside, so that the water may overflow from the drain pan. Patent Document 1 does not describe a countermeasure for such a problem.

  Therefore, an object of the present invention is to provide an air conditioner in which an indoor heat exchanger is kept in a clean state, and in which water does not easily overflow from a drain pan.

  In order to solve the above problems, in the air conditioner according to the present invention, the control unit performs a process of causing the indoor heat exchanger to function as an evaporator, freezing or dew condensation of the indoor heat exchanger, and reducing the outside air temperature to the third level. When the process is performed when the temperature is equal to or less than one threshold, the operation time of the process is shortened as compared with the case where the process is performed when the outside air temperature is higher than the first threshold.

  ADVANTAGE OF THE INVENTION According to this invention, an indoor heat exchanger can be made into a clean state, and also an air conditioner with which water does not easily overflow from a drain pan can be provided.

It is a lineblock diagram of the air harmony machine concerning a 1st embodiment of the present invention. It is a longitudinal section of the indoor unit of the air harmony machine concerning a 1st embodiment of the present invention. It is a functional block diagram of the air conditioner concerning a 1st embodiment of the present invention. It is a flowchart of the process regarding the freezing washing | cleaning of the indoor heat exchanger with which the air conditioner which concerns on 1st Embodiment of this invention is provided. It is explanatory drawing which shows the state in the process of defrosting of the indoor heat exchanger with which the air conditioner which concerns on 1st Embodiment of this invention is provided. It is a flowchart of the process which the control part of the air conditioner concerning 1st Embodiment of this invention performs. It is a flowchart of the process which the control part of the air conditioner which concerns on 2nd Embodiment of this invention performs.

<< First Embodiment >>
<Configuration of air conditioner>
FIG. 1 is a configuration diagram of an air conditioner 100 according to the first embodiment.
In addition, the solid line arrow of FIG. 1 has shown the flow of the refrigerant | coolant at the time of heating operation.
On the other hand, broken line arrows in FIG. 1 indicate 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. The air conditioner 100 includes an indoor heat exchanger 15, an indoor fan 16, and a four-way valve 17 in addition to the above-described configuration.

The compressor 11 is a device that compresses a low-temperature and low-pressure gas refrigerant and discharges it as a high-temperature and high-pressure gas refrigerant. As shown in FIG. 1, the compressor 11 includes a compressor motor 11a that is a drive source.
The outdoor heat exchanger 12 is a heat exchanger in which heat exchange is performed between the refrigerant flowing through the heat transfer tube (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 that is a drive source, and is disposed in the vicinity of the outdoor heat exchanger 12.
The expansion valve 14 is a valve that decompresses the refrigerant condensed in 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 an “evaporator” (the other of the outdoor heat exchanger 12 and the indoor heat exchanger 15).

The indoor heat exchanger 15 performs heat exchange between the refrigerant flowing through the heat transfer tube g (see FIG. 2) and the indoor air sent from the indoor fan 16 (air in the air-conditioning target space). It is a vessel.
The indoor fan 16 is a fan that sends room air into the indoor heat exchanger 15. The indoor fan 16 has 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 that switches the flow path of the refrigerant according to the operation mode of the air conditioner 100. For example, during the cooling operation (see the broken line arrow in FIG. 1), in the refrigerant circuit Q, the compressor 11, the outdoor heat exchanger 12 (condenser), the expansion valve 14, and the indoor heat exchanger 15 (evaporator). The refrigerant circulates in the refrigeration cycle through the above.

  On the other hand, during the heating operation (see the solid arrow in FIG. 1), in the refrigerant circuit Q, the compressor 11, the indoor heat exchanger 15 (condenser), the expansion valve 14, and the outdoor heat exchanger 12 (evaporator). , The refrigerant circulates in the refrigeration cycle.

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

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

FIG. 2 is a longitudinal sectional view of the indoor unit Ui.
As shown in FIG. 2, in addition to the indoor heat exchanger 15 and the indoor fan 16, the indoor unit Ui includes a drain pan 18 (also referred to as a dew pan), a housing base 19, and filters 20a and 20b. I have. Further, the indoor unit Ui includes a front panel 21, a left / right wind direction plate 22, and an up / down wind direction plate 23.

  The indoor heat exchanger 15 includes a plurality of fins f and a plurality of heat transfer tubes g penetrating the fins f. Further, from another viewpoint, the indoor heat exchanger 15 includes a front indoor heat exchanger 15 a disposed on the front side of the indoor fan 16 and a rear indoor heat exchanger 15 b disposed on the rear side of the indoor fan 16. And. In the example illustrated in FIG. 2, the upper end portion of the front indoor heat exchanger 15a and the upper end portion 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 arranged near the indoor heat exchanger 15. The indoor fan 16 includes a plurality of fan blades 16a, a partition plate 16b on which these fan blades 16a are installed, and an indoor fan motor 16c (see FIG. 3) as a drive source.

The drain pan 18 receives condensed water in the indoor heat exchanger 15 and is arranged below the indoor heat exchanger 15.
The housing base 19 is a housing in which devices such as the indoor heat exchanger 15 and the indoor fan 16 are installed.

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

The front panel 21 is a panel that is installed so as to cover the front filter 20a, and is rotatable forward with the lower end as an axis. The front panel 21 may be configured not to rotate.
The left / right wind direction plate 22 is a plate-like member that adjusts the wind direction in the left / right direction of the air blown into the room. The left and right wind direction plates 22 are arranged in the blowing air path h3 and are rotated in the left and right directions by a left and right wind direction plate motor 24 (see FIG. 3).

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

  The air sucked in through the air inlets h1 and h2 exchanges heat with the refrigerant flowing through the heat transfer tube g of the indoor heat exchanger 15, and the heat-exchanged air is guided to the outlet air passage h3. And the air which flows through the blowing wind path h3 is guide | induced to the predetermined direction by the right-and-left wind direction plate 22 and the up-and-down wind direction plate 23, and is further blown out indoors through the air blower outlet h4.

  Most of the dust traveling toward the air inlets h1 and h2 with the flow of air is collected by the filters 20a and 20b. However, since fine dust may pass through the filters 20a and 20b and adhere to the indoor heat exchanger 15, it is desirable to periodically clean the indoor heat exchanger 15. So, in this embodiment, after freezing and frosting with the indoor heat exchanger 15, the indoor heat exchanger 15 is defrosted and washed. Hereinafter, a series of processes including frosting and thawing of the indoor heat exchanger 15 is referred to as “freezing cleaning” of the indoor heat exchanger 15.

FIG. 3 is a functional block diagram of the air conditioner 100.
The indoor unit Ui shown in FIG. 3 includes a remote control transmission / reception unit 26, an environment detection unit 27, and an indoor control circuit 31 in addition to the above-described components.
The remote control transmission / reception unit 26 exchanges predetermined information with the remote control 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 27c.
The indoor temperature sensor 27a is a sensor that detects the temperature of the room (the air conditioning target space), and is installed, for example, on the air suction side of the filters 20a and 20b (see FIG. 2).

The humidity sensor 27b is a sensor that detects the humidity of room air, and is installed at a predetermined position of the indoor unit Ui.
The indoor heat exchanger temperature sensor 27 c is a sensor that detects the temperature of the indoor heat exchanger 15 (see FIG. 2), and is installed 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 to include electronic circuits such as a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and various interfaces. Then, the program stored in the ROM is read out and expanded in the RAM, and 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 31b.
In addition to a predetermined program, the storage unit 31a stores data received via the remote control transmission / reception unit 26, detection values of each sensor, and the like.
The indoor control unit 31b controls the indoor fan motor 16c, the left / right wind direction plate motor 24, the up / down wind direction plate motor 25, and the like based on the data stored in the storage unit 31a.

The outdoor unit Uo includes an outdoor temperature sensor 28 and an outdoor control circuit 32 in addition to the above-described configuration.
The outdoor temperature sensor 28 is a sensor that detects an outdoor temperature, and is installed at a predetermined location of the outdoor unit Uo (see FIG. 1). Although omitted in FIG. 3, the outdoor unit Uo also includes a plurality of sensors that detect the suction temperature, discharge temperature, discharge pressure, and the like of the compressor 11 (see FIG. 1). The detection value of each sensor including the outdoor temperature sensor 28 is output to the outdoor control circuit 32.

  Although not shown, the outdoor control circuit 32 includes electronic circuits such as a CPU, a ROM, a RAM, and various interfaces, 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 32b.

The storage unit 32a stores data received from the indoor control circuit 31 in addition to a predetermined program. 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 32a. Hereinafter, the indoor control circuit 31 and the outdoor control circuit 32 are collectively referred to as a “control unit 30”.
Next, the process of the control part 30 regarding the freezing washing | cleaning of the indoor heat exchanger 15 is demonstrated using FIG.

<Processing of control unit>
FIG. 4 is a flowchart of processing related to freezing and cleaning of the indoor heat exchanger 15 (see FIGS. 2 and 3 as appropriate).
In step S101 in 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, causes the moisture in the air to frost on the indoor heat exchanger 15, and freezes the indoor heat exchanger 15.

Describing step S101 in more detail, the control unit 30 drives the compressor 11 (see FIG. 1), and further makes the opening of the expansion valve 14 (see FIG. 1) smaller than during the cooling operation. As a result, a refrigerant having a low pressure and a low evaporation temperature flows into the indoor heat exchanger 15, so that moisture in the air forms frost on the indoor heat exchanger 15, and further, the frost and ice (symbol i shown in FIG. 5). Becomes easier to grow.
Next, in step S102, the control unit 30 defrosts the indoor heat exchanger 15.

FIG. 5 is an explanatory diagram illustrating a state where the indoor heat exchanger 15 is being thawed.
After the indoor heat exchanger 15 is frozen, the control unit 30 stops devices such as the indoor fan 16 and the compressor 11 (see FIG. 1), for example. As a result, frost and ice (symbol i shown in FIG. 5) in the indoor heat exchanger 15 are naturally thawed at room temperature, and a large amount of water w flows down to the drain pan 18 through the fins f. Thereby, the dust j adhering to the indoor heat exchanger 15 is washed away.

  After freezing and thawing of the indoor heat exchanger 15 (S101 and S102 in FIG. 4), the control unit 30 may perform a heating operation or a blowing operation to dry the inside of the indoor unit Ui. Thereby, propagation of fungi such as mold in the indoor unit Ui can be suppressed.

  By the way, when the outside air temperature is too low (for example, when the temperature is below freezing), a drain hose (not shown) may freeze and water may not flow. In the conventional technology, when the drain hose is clogged as described above, water generated by the thawing of the indoor heat exchanger 15 may overflow from the drain pan 18.

  In consideration of such a situation, for example, while the outside air temperature is below freezing, the control unit 30 may continue to prohibit the freezing and washing of the indoor heat exchanger 15. However, if prohibition of freezing and washing is too long, dirt accumulates in the indoor heat exchanger 15, which may lead to a reduction in efficiency of air conditioning operation and bacterial growth. Therefore, in the present embodiment, even if the outside air temperature is equal to or lower than the predetermined temperature (first threshold value), the freeze cleaning is intentionally 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 unit 30 (see FIG. 3 as appropriate).
It is assumed that the air conditioning operation is not performed during “START” in FIG.
In step S201, the control unit 30 determines whether a predetermined cleaning condition is satisfied. The “cleaning condition” is, for example, a condition that a value obtained by integrating the execution time of the air conditioning operation has reached a predetermined value from the end of the previous freeze cleaning.

  When the predetermined cleaning condition is satisfied in step S201 (S201: Yes), the process of the control unit 30 proceeds to step S202. On the other hand, when the predetermined cleaning condition is not satisfied (S201: No), the control unit 30 repeats the process of step S201.

  In step S202, the control unit 30 determines whether or not the outside air temperature detected by the outdoor temperature sensor 28 (see FIG. 3) is equal to or less than a first threshold. The above-mentioned “first threshold value” is a threshold value that serves as a criterion for determining whether or not to set the freeze cleaning prohibition period (S204), and is set in advance. For example, in step S202, the control unit 30 determines whether or not the outside air temperature is below freezing (whether or not a drain hose (not illustrated) may be clogged with icing or the like).

  If the outside air temperature is equal to or lower than the first threshold value in step S202 (S202: Yes), the control unit 30 performs freeze cleaning in step S203. That is, the control part 30 performs the process (refer FIG. 4, FIG. 5) which makes the indoor heat exchanger 15 function as an evaporator, and freezes this indoor heat exchanger 15.

  After performing the freeze washing in step S203, the control unit 30 sets a predetermined prohibition period in step S204. This prohibition period is a period for prohibiting freezing and washing of the indoor heat exchanger 15, and its length is set in advance.

  For example, when the control unit 30 performs freeze cleaning (freezing / thawing) of the indoor heat exchanger 15 in a state where the drain hose (not shown) is frozen and water does not flow, the water that has flowed down from the indoor heat exchanger 15 is removed. Collected in the drain pan 18. As described above, the length of the freeze-cleaning prohibition period is set in advance as a period (for example, several tens of hours) until most of the water accumulated in the drain pan 18 evaporates by natural convection or the like.

  The capacity of the drain pan 18 is designed so that the water does not overflow even if the indoor heat exchanger 15 is freeze-washed once with a drain hose (not shown) frozen and no water flowing. It is set appropriately at each stage.

  After setting the freeze-cleaning prohibition period in step S204 of FIG. 6, the control unit 30 prohibits the freeze-cleaning 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. When the prohibition period has not elapsed (S206: Yes), the process of the control unit 30 returns to step S205. That is, the control unit 30 prohibits the next freeze washing until the predetermined prohibition period has elapsed. Accordingly, it is possible to prevent the freezing and washing from being performed a plurality of times in a short period of time in a state where the drain hose (not shown) is frozen and clogged, and as a result, the drain pan 18 can be prevented from overflowing water.

  If the prohibition period has elapsed in step S206 (S206: Yes), the process of the control unit 30 returns to "START" (RETURN). This is because the water in the drain pan 18 has almost evaporated at the time when the prohibition period has elapsed, and there is no particular problem even if freeze washing is performed again thereafter. That is, even if the drain hose (not shown) freezes and water does not flow, and water has accumulated in the drain pan 18 after freezing and washing, the water is almost evaporated by natural convection when the prohibition period elapses.

When 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 freezing cleaning (see FIGS. 4 and 5) of the indoor heat exchanger 15 as usual. After performing the process of step S207, the process of the control unit 30 returns to "START" (RETURN).

<Effect>
According to the first embodiment, when the control unit 30 performs the freeze cleaning process when the outside air temperature is equal to or lower than the first threshold (S202: Yes, S203 in FIG. 6), the control unit 30 performs a predetermined process after performing the freeze cleaning. Until the prohibition period elapses, the next freeze cleaning is not started (S205, S206: No). Thereby, for example, even when the drain hose (not shown) freezes and water does not flow, the indoor heat exchanger 15 can be kept clean because it is frozen and washed.

  Further, during the above-described prohibition period, the freeze cleaning of the indoor heat exchanger 15 is prohibited (S205, S206: No in FIG. 6), so that the freeze cleaning can be prevented from being performed a plurality of times in a short period. Therefore, it is possible to prevent water accompanying freezing and washing from overflowing the drain pan 18.

<< 2nd Embodiment >>
In the second embodiment, 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 relatively short, the control unit 30 sets the freezing time of the indoor heat exchanger 15 to be shorter than the previous time. The point of shortening is different from the first embodiment. Others (such as the configuration of the air conditioner 100) are the same as in the first embodiment. Therefore, a different part from 1st Embodiment is demonstrated and description is abbreviate | omitted about the overlapping part.

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).
At the time of "START" in FIG. 7, it is assumed that the air conditioning operation is not performed. Steps S301 and S302 are the same as steps S201 and S202 (see FIG. 6) of the first embodiment, and thus the description thereof is omitted.

When the outside air temperature is equal to or lower than the first threshold value in step S302 of FIG. 7 (S302: Yes), 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 shorter than a predetermined time. More specifically, in step S303, the control unit 30 determines whether or not the elapsed time from the end of the previous freeze cleaning to the start of the current freeze cleaning is a predetermined time or less. The aforementioned “predetermined time” is a threshold value that is a criterion for determining whether or not the current freezing time is shorter than the previous time (S304).

In step S303, when the elapsed time from the previous freeze cleaning is equal to or shorter than the predetermined time (S303: Yes), the process of the control unit 30 proceeds to step S304.
In step S <b> 304, the control unit 30 shortens the current freezing time (the control continuation time during which the temperature of the indoor heat exchanger 15 shown in FIG. 3 is kept below a predetermined value) from the previous 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 (for example, at the previous freeze cleaning).

  If the outside air temperature is equal to or lower than the first threshold value (S302: Yes) and the elapsed time from the previous freeze washing is equal to or shorter than a predetermined time (S303: Yes), water accompanying the previous freeze washing is removed. It is highly likely that the water has not completely evaporated and remains in the drain pan 18 (see FIG. 5).

  Therefore, in the present embodiment, the control unit 30 sets the current freezing time of the indoor heat exchanger 15 to be shorter than the previous freezing time (S304). As a result, the amount of frost and ice adhering to the indoor heat exchanger 15 becomes smaller than that in the previous freeze cleaning. Therefore, since the amount of water flowing down from the indoor heat exchanger 15 to the drain pan 18 in the subsequent thawing is smaller than that in the previous freeze cleaning, it is possible to prevent the water from overflowing from the drain pan 18.

  Note that the length of the freezing time (freezing time shorter than the time of the previous freeze cleaning) in step S304 is set in advance so that water does not overflow from the drain pan 18 even if the freeze cleaning is repeated within a relatively short period of time. Have been.

  Next, in step S305 in FIG. 7, the control unit 30 executes the freeze cleaning of the indoor heat exchanger 15 based on the freezing time set in step S304. After performing the process of step S305, the process of the control unit 30 returns to “START” (RETURN).

  When the outside air temperature is higher than the first threshold value in step S302 (S302: No), in step S306, the control unit 30 performs the freeze cleaning of the indoor heat exchanger 15 based on the normal freezing time. 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 hose (not shown).

  Also, in step S303, if the elapsed time from the previous freeze washing is longer than the predetermined time (S303: No), the process of the control unit 30 proceeds to step S306. This is because, when the “predetermined time” has elapsed, there is a high possibility that most of the water accumulated in the drain pan 18 has evaporated. In other words, if the drain hose (not shown) freezes and water does not flow, and water has accumulated in the drain pan 18 after the previous freeze cleaning, if the elapsed time from the previous freeze cleaning is longer than the predetermined time ( S303: No), water is almost evaporated by natural convection. Therefore, there is no particular problem even if the control unit 30 performs freeze cleaning as usual in step S306. After performing the process of step S306, the process of the control unit 30 returns to "START" (RETURN).

<Effect>
According to the second embodiment, the outside air temperature is equal to or lower than the first threshold (S302: Yes), 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 less than a predetermined time. If it is (S303: Yes), the control unit 30 shortens the operation time of the current freeze cleaning from the previous time (S304). Thereby, for example, even when the drain hose (not shown) freezes and water does not flow, the indoor heat exchanger 15 can be kept clean because it is frozen and washed.

  In addition, the control unit 30 shortens the operation time of the freeze-washing this time from the previous time (S304), so that the water accompanying the freeze-washing can be prevented from overflowing from the drain pan 18.

≪Modification≫
As mentioned above, although each embodiment demonstrated the air conditioner 100 which concerns on this invention, this invention is not limited to these description, A various change can be performed.
For example, instead of freezing / thawing the indoor heat exchanger 15, the control unit 30 may cause the indoor heat exchanger 15 to function as an evaporator and cause the indoor heat exchanger 15 to condense. For example, the control unit 30 causes the temperature of the indoor heat exchanger 15 to be equal to or lower than the dew point of the indoor air and higher than a predetermined freezing temperature (a temperature at which the indoor heat exchanger 15 starts to freeze). The opening degree of the expansion valve 14 is adjusted. Thereby, the indoor heat exchanger 15 is condensed, and the indoor heat exchanger 15 is washed away with the condensed water.

  In addition, in the second embodiment, in addition to the first embodiment, the control unit 30 causes the indoor heat exchanger 15 to function as an evaporator and freezes or condenses the indoor heat exchanger 15 (also referred to as “freezing and washing”). ) May be performed. Even with such a configuration, it is possible to provide the air conditioner 100 in which the indoor heat exchanger 15 is in a clean state and water is not easily overflowed from the drain pan 18.

  Further, in the first embodiment, the process (S204) in which the control unit 30 sets a prohibition period of the next freeze cleaning based on the outside air temperature at the start of the freeze cleaning (S203 in FIG. 6) has been described. However, it is not limited to this. For example, the control unit 30 may provide a predetermined prohibition period based on the outside air temperature at a predetermined timing when performing freeze cleaning or the like. Further, the control unit 30 may provide a predetermined prohibition period based on the outside air temperature at the end of the freeze cleaning or the like. That is, the control unit 30 may provide a period for prohibiting the next freeze cleaning based on the outside air temperature during the freeze cleaning.

  In the first embodiment, the case where the length of the freeze-cleaning prohibition period (S204 in FIG. 6) is a fixed value has been described, but the present invention is not limited to this. For example, the higher the room temperature during the processing such as freeze washing or the lower the indoor humidity (relative humidity or absolute humidity) during the processing such as freeze cleaning, the longer the control unit 30 sets the prohibition period of the freeze cleaning or the like. The length may be shortened. This is because the water accumulated in the drain pan 18 is more likely to evaporate as the room temperature is higher and the room humidity is lower.

  In the second embodiment, when the controller 30 sets the current freezing time of the indoor heat exchanger 15 shorter than the previous time (S304 in FIG. 7), the controller 30 sets the current freezing time as follows. Good. That is, the control unit 30 shortens the current freezing time (operating time for freezing and washing) as the indoor temperature during the freezing and washing process is high or the indoor humidity during the freezing and washing process is low. You may do it. Further, the control unit 30 may shorten the current freezing time as the elapsed time from the end of the previous freezing cleaning to the start of the current freezing cleaning is shorter. Accordingly, it is possible to appropriately set the length of the freezing time when performing freeze cleaning.

  Further, in the first embodiment, a description will be given of a process in which the control unit 30 determines whether or not a predetermined cleaning condition has been satisfied (S201) after a lapse of a freeze cleaning prohibition period (S206: Yes, RETURN in FIG. 6). However, it is not limited to this. For example, after setting the prohibition period for freeze cleaning, the control unit 30 repeatedly determines whether or not a predetermined cleaning condition is satisfied, and even if this cleaning condition is satisfied, The control unit 30 may prohibit the freeze cleaning.

  In the first embodiment, a description will be given of a process in which the control unit 30 appropriately performs the freeze cleaning (S203, S207) of the indoor heat exchanger 15 when a predetermined cleaning condition is satisfied (S201 in FIG. 6: Yes). However, it is not limited to this. 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 or the like.

  Also, when a command to start freeze washing or the like is input from the remote controller 40 (see FIG. 3) during the period of prohibition of freeze washing or the like, the control unit 30 does not start the freeze washing or the like according to the start command. Is preferred. In this case, it may be notified by voice or an image that freeze cleaning or the like is not started. This prevents water from overflowing from the drain pan 18 and can notify the user that freeze cleaning or the like will not be started.

  Further, when a start command for freeze cleaning or the like is input from the remote controller 40 (see FIG. 3) during the period of prohibition of freeze cleaning or the like, the control unit 30 may start the freeze cleaning or the like after the prohibition period elapses. Good. As a result, it is possible to perform freeze cleaning or the like in accordance with the start command from the remote controller 40 while preventing the water from overflowing the drain pan 18.

  Further, when a start command for freeze cleaning or the like is input from the remote controller 40 (see FIG. 3) during the period of prohibition of freeze cleaning or the like, the outside air temperature at the time of input of the start command is higher than the second threshold. When the value is equal to or more than the threshold, the control unit 30 may shorten the length of the prohibition period, or may start the freeze washing or the like in response to the start command. The aforementioned second threshold is, for example, a temperature threshold higher than 0 ° C., and is set in advance. That is, as the outside air temperature rises, if the water can be discharged through a drain hose (not shown), the control unit 30 performs freezing washing or the like in response to a start command from the remote controller 40. You may do it. As a result, the prohibition period is prevented from continuing unnecessarily long, and the control unit 30 can promptly start the next freeze cleaning.

  Further, in the second embodiment, the control unit 30 sets the current freezing time shorter than the previous time (S304) based on the outside air temperature, (S302 in FIG. 7), and the elapsed time (S303) from the previous freezing and washing. ), But is not limited to this. For example, the determination process in step S303 may be omitted. That is, when the outside air temperature is equal to or lower than the first threshold value, when the control unit 30 performs processing such as freezing washing, the freezing washing is performed as compared with the case where freezing washing or the like is performed when the outside air temperature is higher than the first threshold value. For example, the operation time may be shortened.

  In addition, the processes of the heating operation and the blowing operation described below may be added to the process 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 air blowing operation may be performed after the freeze cleaning or the like. This is because the water accumulated in the drain pan 18 is easily evaporated by performing the heating operation or the blowing operation. The control unit 30 may perform the other after performing one of the heating operation and the air blowing operation after the freeze cleaning. The same applies to the second embodiment.

  In the first embodiment, the control unit 30 may perform the following processing. That is, the control unit 30 performs the heating operation as the air conditioning operation according to the operation of the remote controller 40 during the prohibition period after the freezing washing or the like when the outside air temperature is equal to or lower than the first threshold. Or, when the air blowing operation is performed, the length of the prohibition period is shortened. This is because the water accumulated in the drain pan 18 is easily evaporated by performing the heating operation or the blowing operation.

  Furthermore, during the prohibition period after the freeze washing or the like, when the heating operation or the air blowing operation is performed as the air conditioning operation according to the operation of the remote controller 40, the control unit 30 determines that the longer the integrated time of the air conditioning operation during the prohibition period is, The length of the prohibition period may be shortened. Thereby, even after the water accumulated in the drain pan 18 has completely evaporated, the prohibition period can be prevented from continuing unnecessarily long.

  Further, when the outside air temperature at the elapse of the prohibition period such as the freeze washing is equal to or less than the first threshold, the control unit 30 may extend the prohibition period. As a result, it is possible to reliably prevent water accompanying freezing and washing from overflowing the drain pan 18.

  Further, in the first embodiment, the process (S204) in which the control unit 30 sets the freeze-cleaning prohibition period based on the detected value of the outside air temperature (S202 in FIG. 6) is described, but the present invention is not limited to this. For example, when the room temperature when the air-conditioning operation is not being performed is equal to or lower than the first threshold, the control unit 30 may set the prohibition period for freeze cleaning. Furthermore, the control unit 30 may shorten the length of the prohibition period as the room temperature is higher and the room humidity is lower. Thereby, even in a configuration in which the outdoor temperature sensor 28 (see FIG. 3) is not provided, a prohibition period such as freeze cleaning can be appropriately set.

In the first embodiment and the second embodiment, the case where the outside air temperature is below freezing point has been described as an example of the condition that the outside air temperature is equal to or lower than the first threshold. However, the present invention is not limited to this. For example, in consideration of the possibility of the water in the drain hose (not shown) freezing thereafter, a predetermined value (such as 5 ° C.) higher than 0 ° C. may be set as the first threshold value.
Moreover, you may combine 1st Embodiment and 2nd Embodiment suitably. For example, when the outside air temperature is equal to or lower than the first threshold value (S202: Yes in FIG. 6), the control unit 30 performs freeze cleaning (S203), and after the predetermined prohibition period has passed, the next freeze cleaning operation is performed. You may make it make time shorter than last time.

Moreover, although each embodiment demonstrated the structure in which the indoor unit Ui (refer FIG. 1) and the outdoor unit Uo (refer FIG. 1) were provided one each, it is not restricted to this. That is, a plurality of indoor units connected in parallel may be provided, or a plurality of outdoor units connected in parallel may be provided.
Each embodiment is applicable to various types of air conditioners in addition to the wall-mounted air conditioner 100.

Each embodiment is described in detail for easy understanding of the present invention, and is not necessarily limited to the one having all the described configurations. In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.
In addition, the above-described mechanisms and configurations are those that are considered necessary for the description, and do not necessarily indicate all the mechanisms and configurations on the product.

100 air conditioner 11 compressor 12 outdoor heat exchanger (condenser / evaporator)
13 Outdoor fan 14 Expansion valve 15 Indoor heat exchanger (evaporator / condenser)
Reference Signs List 16 indoor fan 17 four-way valve 18 drain pan 19 housing base 27 environment detecting unit 27a indoor temperature sensor 27b humidity sensor 27c indoor heat exchanger temperature sensor 28 outdoor temperature sensor 30 control unit 40 remote control Q refrigerant circuit Uo outdoor unit Ui indoor unit

In order to solve the above problems, in the air conditioner according to the present invention, the control unit performs a process of causing the indoor heat exchanger to function as an evaporator, freezing or dew condensation of the indoor heat exchanger, and reducing the outside air temperature to the third level. When the processing is performed when the temperature is equal to or less than one threshold value, the operation time of the processing is shortened as compared with the case where the processing is performed when the outside air temperature is higher than the first threshold value. It is characterized in that the value of the water discharged from the tank is a value that may freeze .

Claims (4)

A refrigerant circuit in which refrigerant circulates sequentially through a compressor, a condenser, an expansion valve, and an evaporator,
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, the other is an indoor heat exchanger,
Further comprising a drain pan disposed below the indoor heat exchanger;
The controller is
The indoor heat exchanger is made to function as the evaporator, and the indoor heat exchanger is frozen or condensed.
An air conditioner that shortens the operation time of the process when the process is performed when the outside air temperature is equal to or lower than the first threshold, compared to when the process is performed when the outside air temperature is higher than the first threshold. When the outside air temperature is equal to or less than the first threshold and the elapsed time from the end of the previous process to the start of the current process is equal to or less than a predetermined time, the control unit performs the operation of the current process. The air conditioner according to claim 1, wherein the time is shorter than the previous time. The air conditioner according to claim 1, wherein the outside air temperature is equal to or lower than the first threshold value when the outside air temperature is below freezing. The air conditioner according to claim 1, wherein the control unit performs a heating operation or a blowing operation after the processing when the processing is performed when the outside air temperature is equal to or lower than the first threshold value.

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