CN115210509A

CN115210509A - Air conditioner

Info

Publication number: CN115210509A
Application number: CN202180004359.4A
Authority: CN
Inventors: 小泽佳矩; 青木一马
Original assignee: Hitachi Johnson Controls Air Conditioning Inc
Current assignee: Hitachi Johnson Controls Air Conditioning Inc
Priority date: 2021-02-01
Filing date: 2021-02-01
Publication date: 2022-10-18
Also published as: JPWO2022162942A1; TWI808635B; TW202232032A; JP6945100B1; WO2022162942A1

Abstract

The invention provides an air conditioner, which enables a heat exchanger to be in a clean state. The air conditioner (100) is provided with a compressor (11), an outdoor heat exchanger (12), an expansion valve (14), and an indoor heat exchanger (15), and is also provided with a control unit which causes the heat exchanger, which is the indoor heat exchanger (15) or the outdoor heat exchanger (12), to function as an evaporator and performs a process of freezing or condensing the heat exchanger, wherein the control unit performs a control of raising the temperature of the heat exchanger prior to the process.

Description

Air conditioner

Technical Field

The present invention relates to an air conditioner.

Background

As a technique for cleaning a heat exchanger of an air conditioner, for example, a technique described in patent document 1 is known. That is, patent document 1 describes: the control unit performs an operation of lowering the temperature of the heat exchanger, and performs a freezing operation of attaching frost or ice to the fin surfaces.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2018-189270

Disclosure of Invention

Problems to be solved by the invention

In addition, there is a possibility that mist oil suspended in the air adheres to a heat exchanger (e.g., an indoor heat exchanger) during air conditioning operation. As time passes, the oxidation degree of the oil on the heat exchanger surface increases, and the oil is fixed to the heat exchanger. In such a heat exchanger, even if the heat exchanger is cleaned by the technique described in patent document 1, for example, there is a possibility that leaked oil remains in the heat exchanger. That is, the technique described in patent document 1 has room for improvement in terms of bringing the heat exchanger into a clean state.

Accordingly, an object of the present invention is to provide an air conditioner in which a heat exchanger is brought into a clean state.

Means for solving the problems

In order to solve the above problems, an air conditioner according to the present invention includes a compressor, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger, and further includes a control unit that causes the heat exchanger, which is the indoor heat exchanger or the outdoor heat exchanger, to function as an evaporator and performs a process of freezing or condensing the heat exchanger, wherein the control unit performs a control of increasing a temperature of the heat exchanger before the process.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, an air conditioner in which a heat exchanger is brought into a clean state can be provided.

Drawings

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

Fig. 2 is a vertical cross-sectional view of an indoor unit provided in the air conditioner according to the first embodiment.

Fig. 3 is a perspective view of the outdoor unit of the air conditioner according to the first embodiment with the side panel and the top panel of the casing removed.

Fig. 4 is a functional block diagram of the air conditioner according to the first embodiment.

Fig. 5 is a flowchart relating to a cleaning operation of the indoor heat exchanger of the air conditioner according to the first embodiment.

Fig. 6 is an explanatory diagram illustrating a state in the process of defrosting the indoor heat exchanger provided in the air conditioner according to the first embodiment.

Fig. 7 is a timing chart showing changes in the opening degree of the expansion valve, the rotation speeds of the indoor fan and the outdoor fan, and the temperature of the indoor heat exchanger, in addition to the states of the compressor and the four-way valve, in the air conditioner according to the first embodiment.

Fig. 8 is a vertical cross-sectional view of an indoor unit provided in an air conditioner according to a second embodiment.

Fig. 9 is a functional block diagram of an air conditioner according to a second embodiment.

Fig. 10 is a timing chart showing changes in the opening degree of the expansion valve, the rotation speeds of the indoor fan and the outdoor fan, the state of the heater, and the temperature of the indoor heat exchanger, in addition to the states of the compressor and the four-way valve, in the air conditioner according to the second embodiment.

Fig. 11 is a vertical sectional view of an indoor unit provided in an air conditioner according to a third embodiment.

Fig. 12 is a functional block diagram of an air conditioner according to a third embodiment.

Fig. 13 is a vertical cross-sectional view of an indoor unit provided in an air conditioner according to a fourth embodiment.

Fig. 14 is a functional block diagram of an air conditioner according to the fourth embodiment.

Fig. 15 is a flowchart relating to a cleaning operation of the indoor heat exchanger of the air conditioner according to the fourth embodiment.

Fig. 16 is a perspective view of a filter and a filter cleaning unit provided in an indoor unit of an air conditioner according to a fifth embodiment.

Fig. 17 is a flowchart relating to a cleaning operation of the outdoor heat exchanger of the air conditioner according to the sixth embodiment.

Fig. 18 is a timing chart showing changes in the opening degree of the expansion valve, the rotation speeds of the indoor fan and the outdoor fan, and the temperature of the outdoor heat exchanger, in addition to the states of the compressor and the four-way valve, in the air conditioner according to the sixth embodiment.

Fig. 19 is a flowchart relating to a cleaning operation of the indoor heat exchanger and the outdoor heat exchanger of the air conditioner according to the seventh embodiment.

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 indicate the flow of the refrigerant during the heating operation.

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

The air conditioner 100 is an apparatus for performing air conditioning such as a cooling operation and a heating 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 further includes: an indoor heat exchanger 15 (heat exchanger), an indoor fan 16 (fan), and a four-way valve 17.

The compressor 11 is a device that compresses a low-temperature/low-pressure gas refrigerant and discharges the compressed gas refrigerant as a high-temperature/high-pressure gas refrigerant, and includes a compressor motor 11a as a drive source. As such a compressor 11, a scroll compressor, a rotary compressor, or the like can be used. Although not shown in fig. 1, an accumulator 9 (see fig. 3) is connected to the suction side of the compressor 11, and the accumulator 9 is used for gas-liquid separation of the refrigerant.

The outdoor heat exchanger 12 is a heat exchanger that exchanges heat between the refrigerant flowing through the heat transfer tubes 12b (see fig. 3) and the outside air sent by 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 provided 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 is a heat exchanger that exchanges heat between the refrigerant flowing through the heat transfer pipe 15b (see fig. 2) and the indoor air (air in the air-conditioning room) sent by 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 16a (see fig. 4) as a drive source, and is provided 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. The air conditioner 100 is configured to include a refrigerant circuit 10, and the refrigerant circuit 10 is formed by connecting a compressor 11, an outdoor heat exchanger 12, an expansion valve 14, and an indoor heat exchanger 15 via a four-way valve 17.

For example, during a cooling operation (see a dotted arrow in fig. 1), the refrigerant circulates through the refrigerant circuit 10 in order of the compressor 11, the outdoor heat exchanger 12 (condenser), the expansion valve 14, and the indoor heat exchanger 15 (evaporator). On the other hand, during the heating operation (see solid arrows in fig. 1), the refrigerant circulates through the refrigerant circuit 10 in order of the compressor 11, the indoor heat exchanger 15 (condenser), the expansion valve 14, and the outdoor heat exchanger 12 (evaporator).

In the example of 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 30. On the other hand, the indoor heat exchanger 15 and the indoor fan 16 are provided in the indoor unit 20.

Fig. 2 is a longitudinal sectional view of the indoor unit 20.

As shown in fig. 2, the indoor unit 20 includes, in addition to the indoor heat exchanger 15 and the indoor fan 16: drain pan 18, frame 19, and

filters

21a, 21b. The indoor unit 20 further includes: a front panel 22, a horizontal wind direction plate 23, and a vertical wind direction plate 24.

The indoor heat exchanger 15 includes: a plurality of fins 15a; and a plurality of heat transfer tubes 15b penetrating these fins 15 a. In another aspect, the indoor heat exchanger 15 includes: a front indoor heat exchanger 15c disposed in front of the indoor fan 16; and a rear indoor heat exchanger 15d disposed behind the indoor fan 16. In the example of fig. 2, the upper end of the front indoor heat exchanger 15c and the upper end of the rear indoor heat exchanger 15d are connected in an inverted V shape in a vertical cross-sectional view. The structure of the indoor heat exchanger 15 shown in fig. 2 is merely an example and is not limited thereto.

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, in addition to the indoor fan motor 16a (see fig. 4), the following: a plurality of fan blades 16b, and an annular partition plate 16c on which the fan blades 16b are provided.

The drain pan 18 receives the dew condensation water of the indoor heat exchanger 15 and is disposed below the indoor heat exchanger 15.

The housing 19 houses the indoor heat exchanger 15, the indoor fan 16, and the like.

The

filters

21a and 21b collect dust from the air that moves toward the indoor heat exchanger 15, and are disposed in the vicinity of the indoor heat exchanger 15. One filter 21a is disposed on the front side of the indoor heat exchanger 15, and the other filter 21b is disposed on the upper side of the indoor heat exchanger 15.

The front panel 22 is a panel provided to cover the front filter 21a, and is rotatable forward with the lower end as the axial direction. The front panel 22 may not rotate.

The horizontal air vanes 23 are plate-like members that adjust the horizontal direction of the air blown out from the indoor fan 16. The horizontal air vanes 23 are disposed in the outlet air duct 26 and can be rotated in the horizontal direction by a horizontal air vane motor 34 (see fig. 4).

The up-down airflow direction plate 24 is a plate-like member that adjusts the vertical airflow direction of the air blown out from the indoor fan 16. The up-down wind direction plate 24 is disposed in the air outlet 27 and is rotatable in the up-down direction by a motor 35 for up-down wind direction plate (see fig. 4).

The air sucked through the

air suction ports

25a and 25b exchanges heat with the refrigerant flowing through the heat transfer pipe 15b of the indoor heat exchanger 15, and the heat-exchanged air is guided to the outlet air passage 26. The air flowing through the outlet air duct 26 is guided in a predetermined direction by the horizontal wind direction plate 23 and the vertical wind direction plate 24, and is blown out to the air-conditioned room through the air outlet 27.

Most of the dust that advances toward the

air suction ports

25a and 25b with the flow of the air is collected by the

filters

21a and 21b. However, fine dust may permeate through the

filters

21a and 21b and adhere to the indoor heat exchanger 15. Also, soot (oil vapor) suspended in the air-conditioned room permeates through the

filters

21a and 21b and adheres to the indoor heat exchanger 15. As time passes, the degree of oxidation of the oil on the surface of the indoor heat exchanger 15 increases, and the oil adheres to the indoor heat exchanger 15. Therefore, it is desirable to periodically clean the indoor heat exchanger 15, but there is a problem in that the oil is difficult to wash away.

Therefore, in the first embodiment, the temperature of the indoor heat exchanger 15 is increased to soften (or liquefy/fluidize) the oil on the surface of the indoor heat exchanger 15, and then the freezing and thawing of the indoor heat exchanger 15 are sequentially performed, so that the oil on the surface of the indoor heat exchanger 15 can be washed away together with the dust. Such a series of processes including heating/freezing/thawing of the indoor heat exchanger 15 is referred to as "a washing operation".

Fig. 3 is a perspective view of the outdoor unit 30 with the side plate and the top plate of the casing 31 removed.

In fig. 3, the expansion valve 14 (see fig. 1) and the four-way valve 17 (see fig. 1) are not shown.

As shown in fig. 3, the casing 31 of the outdoor unit 30 includes: the compressor 11, the outdoor heat exchanger 12, the outdoor fan 13, and an electrical component box 32 are also provided. In the example of fig. 3, a bottom plate 31a of the housing 31 is provided with: an outdoor heat exchanger 12 in an L shape in plan view. The outdoor heat exchanger 12 includes: a plurality of fins 12a arranged at predetermined intervals, and a plurality of heat transfer tubes 12b penetrating these fins 12 a. In the example of fig. 3, a blade fan is used as the outdoor fan 13.

Fig. 4 is a functional block diagram of the air conditioner 100.

The indoor unit 20 shown in fig. 4 includes, in addition to the above-described respective configurations: a remote controller transceiver 28, an indoor temperature sensor 29, an indoor heat exchanger temperature sensor 33 (heat exchanger temperature sensor), a display lamp 36, and an indoor control circuit 4.

The remote control transmitting/receiving unit 28 exchanges predetermined information with the remote control 50 by infrared communication or the like.

The indoor temperature sensor 29 is a sensor for detecting the temperature of the air-conditioned room, and is provided on the air intake side of the indoor heat exchanger 15, for example.

The indoor heat exchanger temperature sensor 33 is a sensor that detects the temperature of the indoor heat exchanger 15 (see fig. 2). The indoor heat exchanger temperature sensor 33 may be provided in the indoor heat exchanger 15, or may be provided in a predetermined refrigerant pipe connected to the indoor heat exchanger 15. The detection values of the indoor temperature sensor 29 and the indoor heat exchanger temperature sensor 33 are output to the indoor control circuit 41. The display lamp 36 is a lamp for performing a predetermined display related to the air conditioner.

Although not shown, the indoor control circuit 41 includes: CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and various interfaces. The CPU can read out the program stored in the ROM, develop the program in the RAM, and execute various processes.

As shown in fig. 3, the indoor control circuit 41 includes a storage unit 41a and an indoor control unit 41b. The storage unit 41a stores data received via the remote controller transmission/reception unit 28, detection values of the sensors, and the like, in addition to a predetermined program. The indoor control unit 41b controls the indoor fan motor 16a, the horizontal air vane motor 34, the vertical air vane motor 35, the indicator lamp 36, and the like based on the data of the storage unit 41 a.

The outdoor unit 30 includes an outdoor temperature sensor 37 and an outdoor control circuit 42 in addition to the above configuration.

The outdoor temperature sensor 37 is a sensor for detecting the temperature of the outside air, and is provided at a predetermined position of the outdoor unit 30. Although not shown in fig. 4, the outdoor unit 30 also includes a sensor or the like for detecting the discharge temperature of the compressor 11 (see fig. 1). The detection values of these sensors are output to the outdoor control circuit 42.

Although not shown, the outdoor control circuit 42 includes: circuits such as a CPU, a ROM, a RAM, and various interfaces are connected to the in-room control circuit 41 via a communication line. As shown in fig. 4, the outdoor control circuit 42 includes a storage unit 42a and an outdoor control unit 42b.

The storage unit 42a stores data and the like received from the indoor control circuit 41 in addition to a predetermined program. The outdoor control unit 42b controls the compressor motor 11a, the outdoor fan motor 13a, the expansion valve 14, the four-way valve 17, and the like based on the data of the storage unit 42 a. The indoor control circuit 41 and the outdoor control circuit 42 are collectively referred to as a control unit 40.

< processing by control section >

Fig. 5 is a flowchart related to the cleaning operation of the indoor heat exchanger (see fig. 1 and 4 as appropriate).

Although omitted in fig. 5, for example, when the integrated value (summed value) of the execution times of the air-conditioning operation, which is integrated from the end of the previous cleaning operation, reaches a predetermined value, the series of processing shown in fig. 5 may be started. Further, for example, when the user performs a predetermined operation on an operation terminal such as a remote controller 50 (see fig. 4), a smartphone, or a mobile phone, the series of processes shown in fig. 5 may be started.

In step S101 of fig. 5, the control unit 40 heats the indoor heat exchanger 15. That is, the control unit 40 performs control to increase the temperature of the indoor heat exchanger 15. As such control, for example, the controller 40 circulates the refrigerant in the refrigerant circuit 10 in a heating cycle, and causes the indoor heat exchanger 15 to function as a condenser. This softens (or liquefies/fluidizes) the oil adhering to the surfaces of the fins 15a (see fig. 2) and the heat transfer pipe 15b (see fig. 2) of the indoor heat exchanger 15. As described above, the control unit 40 performs control for increasing the temperature of the indoor heat exchanger 15 (S101) before performing the process for freezing the indoor heat exchanger 15 (heat exchanger) (S102), which is one of the main features of the first embodiment.

Next, in step S102, the control unit 40 freezes the indoor heat exchanger 15. That is, the controller 40 circulates the refrigerant in the refrigeration cycle in the refrigerant circuit 10, causes the indoor heat exchanger 15 (heat exchanger) to function as an evaporator, and performs a process of freezing the indoor heat exchanger 15.

Next, in step S103, the control unit 40 defrosts the indoor heat exchanger 15. For example, the controller 40 stops the compressor 11 and increases the opening degree of the expansion valve 14. As a result, the high-temperature refrigerant flows from the high-pressure outdoor heat exchanger 12 into the low-pressure indoor heat exchanger 15 via the expansion valve 14, and the indoor heat exchanger 15 is thawed.

Fig. 6 is an explanatory diagram showing a state during defrosting of the indoor heat exchanger 15.

After freezing of the indoor heat exchanger 15 (S102 in fig. 5), the control unit 40 defrosts the indoor heat exchanger 15 (S103), and then flows a high-temperature refrigerant through the heat transfer pipe 15b of the indoor heat exchanger 15. As a result, the frost 61 of the indoor heat exchanger 15 is dissolved, and a large amount of water 62 flows down along the fins 15a to the drain pan 18. In the first embodiment, the controller 40 heats the indoor heat exchanger 15 before the freezing of the indoor heat exchanger 15 (S101). This softens (or liquefies/fluidizes) the oil on the surface of the indoor heat exchanger 15. Further, the oil fixedly attached to the oil is softened by heating due to the increased oxidation degree. After that, the freezing and thawing of the indoor heat exchanger 15 are performed, and the oil can be washed away together with the dust 63 adhering to the indoor heat exchanger 15.

Fig. 7 is a timing chart showing the opening degree of the expansion valve, the rotation speed of the indoor fan and the outdoor fan, and the temperature change of the indoor heat exchanger, in addition to the states of the compressor and the four-way valve (see fig. 1 and 4 as appropriate).

The horizontal axis of fig. 7 represents time. The vertical axis of fig. 7 shows the state of the compressor 11, the four-way valve 17, and the like. In the example of fig. 7, the air conditioner 100 is in a stopped state (a state where air conditioning operation is not performed) before time t 1. Immediately before the air conditioner 100 is brought into the stopped state, for example, a cooling operation is performed (see a state of the "four-way valve" in fig. 7). Before the control of the indoor heat exchanger 15 is performed, the dehumidifying operation and the heating operation may be performed in addition to the cooling operation immediately before the air conditioning operation is stopped.

When heating the indoor heat exchanger 15 (S101 in fig. 5), the control unit 40 switches the four-way valve 17 to the heating cycle at time t1, controls the expansion valve 14 to a predetermined opening degree α 1, and drives the compressor 11. Thus, the indoor heat exchanger 15 functions as a condenser, and the outdoor heat exchanger 12 functions as an evaporator. As a result, the high-temperature refrigerant flows through the indoor heat exchanger 15, and softening of the oil adhering to the surface of the indoor heat exchanger 15 is promoted.

In the example of fig. 7, the control unit 40 drives the indoor fan 16 during the heating process of the indoor heat exchanger 15 (time t1 to time t 2). This can promote heat exchange between the refrigerant flowing through the indoor heat exchanger 15 (condenser) and the air in the air-conditioning room. Therefore, the pressure of the refrigerant in the indoor heat exchanger 15 is suppressed from becoming too high, and the discharge pressure of the compressor 11 is suppressed from becoming too high, thereby preventing a failure of the compressor 11.

When the control for increasing the temperature of the indoor heat exchanger 15 is executed (time t1 to time t2 in fig. 5), the control unit 40 controls the indoor fan 1When the direction of the rotation speed 6 is the same as that in the normal air-conditioning operation, the rotation speed is driven (positive rotation) at a rotation speed equal to or less than a value calculated by dividing the sum of the upper limit value and the lower limit value of the rotation speed of the indoor fan 16 by 2. Here, the "lower limit value" mentioned above means: the lower limit value of the rotation speed of the indoor fan 16 when the control unit 40 drives the compressor 11 during the air conditioning operation. The "lower limit value" does not include the stopped state of the indoor fan 16 (i.e., 0[ min ]) ^-1 ]). When the oil on the surface of the indoor heat exchanger 15 is softened with the heating of the indoor heat exchanger 15, there is a possibility that a smell peculiar to the oil is generated. As described above, the control unit 40 drives the indoor fan 16 at a low speed, and can reduce the volume of air when the oily air is blown into the air-conditioned room.

When the control for increasing the temperature of the indoor heat exchanger 15 is executed (time t1 to time t2 in fig. 5), the controller 40 preferably causes the vertical air vanes 24 (see fig. 2) to face upward from the horizontal direction. Note that the vertical vanes 24 are also oriented upward relative to the horizontal direction, including a state in which the vertical vanes 24 are closed. This can suppress the air that gives off the oily smell from being blown out to the person in the room, and reduce the unpleasant feeling and the uncomfortable feeling of the person in the room.

In the example of fig. 7, during the heating process of the indoor heat exchanger 15 (time t1 to time t 2), the controller 40 drives the indoor fan 16 and also drives the outdoor fan 13. This makes it possible to balance heat radiation from the refrigerant in the indoor heat exchanger 15 (condenser) to the air and heat absorption from the air in the outdoor heat exchanger 12 (evaporator) to the refrigerant.

In the example of fig. 7, during the heating of the indoor heat exchanger 15 (from time t1 to time t 2), the heating of the indoor heat exchanger 15 is continued for a predetermined time Δ from a predetermined time t1a to time t2 (end of heating), and a state where the temperature of the indoor heat exchanger 15 is equal to or higher than a predetermined value Ta is continued. The predetermined value Ta is a temperature threshold value as a criterion for determining whether or not softening of the oil on the surface of the indoor heat exchanger 15 is easy, and is set in advance.

The predetermined value Ta may be set to 40 ℃. In addition, when performing control to increase the temperature of the indoor heat exchanger 15 (heat exchanger), the controller 40 may continue the state in which the temperature of the indoor heat exchanger 15 is 40 ℃ or higher for a predetermined time. The predetermined time (the predetermined time Δ in the example of fig. 7) is a time sufficient for digesting the oil adhering to the indoor heat exchanger 15, and is set in advance.

The predetermined time Δ is preferably shorter than the time (time t3 to time t4 in fig. 7) during which the indoor heat exchanger 15 is frozen. This can suppress unnecessary long-time heating of the indoor heat exchanger 15, improve user comfort, and reduce power consumption of the air conditioner 100.

The time t2 to t3 after the heating of the indoor heat exchanger 15 is a predetermined equilibrium period. In the example of fig. 7, at time t2, the control unit 40 stops the compressor 11, switches the four-way valve 17 to the refrigeration cycle, and increases the opening degree of the expansion valve 14 (e.g., fully opens). By continuing this state from time t2 to t3, the refrigerant is easily circulated in the refrigeration cycle immediately after the start of freezing of the indoor heat exchanger 15 (from time t3 to t 4), and the application of an excessive load to the compressor 11 is suppressed. The timing of switching the four-way valve 17 to the refrigeration cycle (time t2 in fig. 7) is an example and is not limited to this. At time t2 in fig. 7, the expansion valve 14 does not have to be fully opened, and the refrigerant may be allowed to flow through the expansion valve 14.

The control unit 40 preferably stops the indoor fan 16 during a period from when the control of increasing the temperature of the indoor heat exchanger 15 ends (time t2 in fig. 7) to when the process of freezing the indoor heat exchanger 15 starts (time t 3). By thus stopping the indoor fan 16 during the predetermined balance period (time t2 to time t 3), it is possible to reduce the user's uncomfortable feeling due to noise or the like and to reduce the power consumption of the air conditioner 100.

It is preferable that the control unit 40 starts the process of freezing the indoor heat exchanger 15 before a predetermined time elapses from the end of the control of increasing the temperature of the indoor heat exchanger 15 (time t 2). This enables the oil to be washed away with the water during freezing and thawing of the indoor heat exchanger 15 before the softened oil is hardened again. The predetermined time (for example, one hour) is a time until the oil that has been softened is left to stand at normal temperature and is cured and restored to its original state, and is set in advance.

Next, when freezing the indoor heat exchanger 15 (S102 in fig. 5), the control unit 40 controls the expansion valve 14 to the predetermined opening degree α 2 at time t3 in fig. 7, and drives the compressor 11. The predetermined opening degree α 2 may be, for example, an opening degree smaller than that during normal air-conditioning operation. In addition, the four-way valve 17 maintains the state of the refrigeration cycle during freezing of the indoor heat exchanger 15.

Thus, the outdoor heat exchanger 12 functions as a condenser, and the indoor heat exchanger 15 functions as an evaporator. As a result, since the low-pressure refrigerant having a saturation temperature lower than 0 ℃ flows through the indoor heat exchanger 15, moisture in the air is frosted and frozen in the indoor heat exchanger 15. The control unit 40 continues the state in which the detection value of the indoor heat exchanger temperature sensor 33 (see fig. 4) is below the freezing point for a predetermined time, for example.

Even if the temperature of the oil softened during the heating of the indoor heat exchanger 15 (time t1 to time t 2) is rapidly reduced by freezing of the indoor heat exchanger 15, the oil is not immediately hardened (returns to its original state). Therefore, the surface of the frozen indoor heat exchanger 15 is in a state of both softened oil, ice, and frost.

Further, by raising the temperature of the indoor heat exchanger 15, the oil is softened, and oil stains are easily lifted from the surface of the fins 15a and the like. In this state, when the indoor heat exchanger 15 is cooled, moisture enters when the oil floats from the surface. In this state, when the indoor heat exchanger 15 is frozen, the oil further floats from the surface due to the volume expansion of the water generated during the freezing process, and the cleaning is then facilitated.

As shown in fig. 7, during freezing of the indoor heat exchanger 15 (time t3 to time t 4), the control unit 40 preferably stops the indoor fan 16. This can suppress the blowing of the cool air into the air-conditioned room. In the example of fig. 7, the controller 40 drives the outdoor fan 13 during freezing of the indoor heat exchanger 15 (time t3 to time t 4). This can suppress the refrigerant pressure in the outdoor heat exchanger 12 from becoming too high, and can suppress the discharge pressure of the compressor 11 from becoming too high.

After freezing the indoor heat exchanger 15 in this way, the control unit 40 unfreezes the indoor heat exchanger 15 (S103 in fig. 5). That is, at time t4, the controller 40 stops the compressor 11 and the outdoor fan 13, maintains the indoor fan 16 in the stopped state, and increases the opening degree of the expansion valve 14 (e.g., fully opens the expansion valve 14). As a result, the high-temperature refrigerant flows from the high-pressure outdoor heat exchanger 12 into the low-pressure indoor heat exchanger 15 via the expansion valve 14. As a result, frost and ice in the indoor heat exchanger 15 are melted, and the oil can be washed away together with the dust in the indoor heat exchanger 15 (see fig. 6).

Fig. 7 is an example, and the control of each device in the cleaning operation of the indoor heat exchanger 15 is not limited to this. For example, the rotation speed of the compressor 11 and the opening degree of the expansion valve 14 may be appropriately changed during heating or freezing of the indoor heat exchanger 15.

< Effect >

According to the first embodiment, the control unit 40 performs control to increase the temperature of the indoor heat exchanger 15 (S101 in fig. 5), thereby softening the oil fixedly attached to the indoor heat exchanger 15. After softening the oil on the surface of the indoor heat exchanger 15 in this way, the control unit 40 sequentially freezes and unfreezes the indoor heat exchanger 15 (S102 and S103 in fig. 5). This enables the oil on the surface of the indoor heat exchanger 15 to be washed away together with the dust by the water during freezing. Therefore, the indoor heat exchanger 15 can be brought into a clean state. In addition, the heat exchange efficiency between the refrigerant and the air in the indoor heat exchanger 15 can be improved.

Second embodiment

The second embodiment is different from the first embodiment in that a heater 71 (see fig. 8) is provided in the indoor unit 20A (see fig. 8), and the indoor heat exchanger 15 is heated by the heater 71. Otherwise, the same as the first embodiment is applied. Therefore, description will be given of portions different from those of the first embodiment, and description of overlapping portions will be omitted.

Fig. 8 is a vertical cross-sectional view of an indoor unit 20A provided in the air conditioner according to the second embodiment.

As shown in fig. 8, the indoor unit 20A includes a heater 71 in addition to the configuration described in the first embodiment (see fig. 2). The heater 71 is, for example, an electric heater that assists heating of air by appropriately supplying electric power during the heating operation. Further, the heater 71 also has the following functions: the temperature of the indoor heat exchanger 15 is increased by applying current before freezing of the indoor heat exchanger 15, and the oil on the surface of the indoor heat exchanger 15 is softened.

The heater 71 is provided in the vicinity of the indoor heat exchanger 15 (heat exchanger) inside the housing 19. In the example of fig. 8, a heater 71 is provided inside the rear indoor heat exchanger 15d (downstream side of the air flow). The heater 71 is elongated in parallel with the axial direction of the indoor fan 16. Instead of the rear indoor heat exchanger 15d, the front indoor heat exchanger 15c may be provided with the heater 71. The heaters 71 may be provided in the front indoor heat exchanger 15c and the rear indoor heat exchanger 15d, respectively.

Fig. 9 is a functional block diagram of an air conditioner 100A according to the second embodiment.

As shown in fig. 9, the heater 71 is connected to the indoor control circuit 41 via a wire. The heater 71 can be energized in a predetermined manner in accordance with a command from the indoor control unit 41b (i.e., the control unit 40).

Fig. 10 is a timing chart showing the opening degree of the expansion valve, the rotation speed of the indoor fan and the outdoor fan, the state of the heater, and the temperature change of the indoor heat exchanger, in addition to the states of the compressor and the four-way valve (see fig. 1 and 9 as appropriate).

As shown in fig. 10, the control unit 40 turns ON (ON) the heater 71 from time t1 to time t2 when the indoor heat exchanger 15 is heated. That is, the controller 40 energizes the heater 71 when performing control to increase the temperature of the indoor heat exchanger 15 (heat exchanger). Since the indoor heat exchanger 15 is made of metal, the temperature rises not only at the installation location of the heater 71 (see fig. 8) but also substantially over the entire area of the indoor heat exchanger 15. As a result, the oil on the surface of the indoor heat exchanger 15 is softened (or liquefied/fluidized).

In the example of fig. 10, the compressor 11, the indoor fan 16, and the outdoor fan 13 are in a stopped state during the heating process of the indoor heat exchanger 15. The compressor 11 and the like may be stopped as described above as long as the indoor heat exchanger 15 can be sufficiently heated by the heater 71. In addition, the controller 40 may circulate the refrigerant in a heating cycle while the indoor heat exchanger 15 is being heated by the heater 71, or may appropriately drive the indoor fan 16.

After the indoor heat exchanger 15 is heated by the heater 71, the controller 40 causes the indoor heat exchanger 15 to function as an evaporator and freezes the indoor heat exchanger 15 at times t2 to t3 in fig. 10. Note that the process performed during freezing of the indoor heat exchanger 15 is the same as that of the first embodiment, and therefore, description thereof is omitted. During freezing of the indoor heat exchanger 15, the heater 71 is in an OFF state to avoid a temperature rise of the indoor heat exchanger 15.

After freezing the indoor heat exchanger 15, the controller 40 stops the compressor 11 and increases the opening degree of the expansion valve 14 (e.g., fully opens) from time t 3. As a result, the high-temperature refrigerant flows into the indoor heat exchanger 15, and frost on the indoor heat exchanger 15 is thereby removed. When the indoor heat exchanger 15 is defrosted, the opening degree of the expansion valve 14 does not have to be increased, and the refrigerant may be allowed to flow through the expansion valve 14. Preferably, the control unit 40 energizes the heater 71 after freezing the indoor heat exchanger 15. For example, the controller 40 energizes the heater 71 with the expansion valve 14 fully opened during defrosting of the indoor heat exchanger 15.

This promotes thawing of the indoor heat exchanger 15, and the temperature of the water dripping on the drain pan 18 (see fig. 8) is raised by the heat of the heater 71. Therefore, the oil fixedly attached to the surfaces of the drain grooves (not shown) and the drain pipes (not shown) of the drain pan 18 is softened by the heat of the warm water and is removed together with the water. Therefore, oil clogging of the drain tank and the drain pipe can be suppressed.

< Effect >

According to the second embodiment, before the indoor heat exchanger 15 freezes, the controller 40 energizes the heater 71 to soften the oil on the surface of the indoor heat exchanger 15. After that, the freezing and thawing of the indoor heat exchanger 15 are performed in this order, and the oil on the surface of the indoor heat exchanger 15 is washed away together with the dust. Further, during defrosting of the indoor heat exchanger 15, the controller 40 energizes the heater 71, thereby suppressing oil clogging in the drain grooves (not shown) and the drain pipes (not shown) of the drain pan 18.

Third embodiment

The third embodiment is different from the first embodiment in that an ultrasonic irradiator 72 (see fig. 11) is provided in an indoor unit 20B (see fig. 11) and the indoor heat exchanger 15 is heated by ultrasonic waves. Otherwise, the same as the first embodiment is applied. Therefore, portions different from those of the first embodiment will be described, and redundant description will be omitted.

Fig. 11 is a vertical cross-sectional view of an indoor unit 20B provided in the air conditioner according to the third embodiment.

As shown in fig. 11, the indoor unit 20B includes an ultrasonic irradiator 72 in addition to the configuration described in the first embodiment (see fig. 2). The ultrasonic irradiator 72 has the following functions: the indoor heat exchanger 15 is irradiated with ultrasonic waves to raise the temperature of the indoor heat exchanger 15, thereby softening (or liquefying/fluidizing) the oil on the surface of the indoor heat exchanger 15.

The ultrasonic irradiator 72 is provided in the vicinity of the indoor heat exchanger 15 (heat exchanger) inside the housing 19. In the example of fig. 11, an ultrasonic irradiator 72 is provided in the vicinity of the connection portion of the

filters

21a and 21b. The ultrasonic irradiator 72 extends in a long and narrow shape in parallel with the axial direction of the indoor fan 16, and faces the indoor heat exchanger 15 (in the example of fig. 11, the front-side indoor heat exchanger 15 c). The ultrasonic waves irradiated from the ultrasonic irradiator 72 are irradiated to the front indoor heat exchanger 15c, reflected in a predetermined manner on the inner wall surfaces of the frame 19, the front panel 22, and the like, and also irradiated to the rear indoor heat exchanger 15d.

Fig. 12 is a functional block diagram of an air conditioner 100B according to the third embodiment.

As shown in fig. 12, the ultrasonic irradiator 72 and the indoor control circuit 41 are connected via wiring. In addition, the ultrasonic wave can be irradiated from the ultrasonic irradiator 72 in a predetermined manner in accordance with a command from the indoor control unit 41b (i.e., the control unit 40).

The timing of turning ON/OFF (ON/OFF) the ultrasonic irradiator 72 by the control unit 40 is the same as the control of the heater 71 described in the second embodiment (see fig. 10). That is, when performing control to increase the temperature of the indoor heat exchanger 15 (heat exchanger), the control unit 40 irradiates the indoor heat exchanger 15 with ultrasonic waves from the ultrasonic irradiator 72. This generates heat in the indoor heat exchanger 15, and softens the oil on the surface of the indoor heat exchanger 15. If the indoor heat exchanger 15 is sufficiently heated by the ultrasonic irradiator 72, the compressor 11 and the like can be maintained in a stopped state during the heating of the indoor heat exchanger 15.

Further, during freezing of the indoor heat exchanger 15, the control unit 40 maintains the ultrasonic irradiator 72 in an OFF (OFF) state to avoid a temperature rise of the indoor heat exchanger 15. On the other hand, during the defrosting of the indoor heat exchanger 15, the control unit 40 may irradiate the indoor heat exchanger 15 with ultrasonic waves using the ultrasonic irradiator 72. This can promote defrosting of the indoor heat exchanger 15 and increase the temperature of the water dropping on the drain pan 18 (see fig. 11). Therefore, oil clogging of the drain grooves (not shown) and the drain pipes (not shown) of the drain pan 18 can be suppressed.

< Effect >

According to the third embodiment, before the indoor heat exchanger 15 freezes, the controller 40 irradiates the indoor heat exchanger 15 with ultrasonic waves from the ultrasonic irradiator 72 to soften the oil on the surface of the indoor heat exchanger 15. After that, freezing and thawing of the indoor heat exchanger 15 are performed in order, and the oil on the surface of the indoor heat exchanger 15 is washed away together with the dust by the water during freezing.

Fourth embodiment

The fourth embodiment is different from the first embodiment in that an imaging unit 73 is provided in an indoor unit 20C (see fig. 13), and the indoor heat exchanger 15 is heated based on the imaging result of the imaging unit 73. Otherwise, the same as the first embodiment is applied. Therefore, portions different from those of the first embodiment will be described, and redundant description will be omitted.

Fig. 13 is a vertical sectional view of an indoor unit 20C provided in the air conditioner according to the fourth embodiment.

As shown in fig. 13, the indoor unit 20C includes an imaging unit 73 in addition to the configuration described in the first embodiment (see fig. 2). The imaging unit 73 images the air-conditioned room and is provided in the housing 19 in a predetermined manner. In the example of fig. 13, an imaging unit 73 is provided between the front panel 22 and the up-down wind deflector 24 in a vertical cross-sectional view. In addition, the imaging unit 73 is provided in a state of facing downward at a predetermined angle with respect to the horizontal direction in order to image the air-conditioned room.

Fig. 14 is a functional block diagram of an air conditioner 100C according to the fourth embodiment.

Although not shown, the imaging unit 73 shown in fig. 14 includes an imaging Device (not shown) such as a CCD sensor (Charge Coupled Device) or a CMOS sensor (Complementary Metal Oxide Semiconductor), and is connected to the indoor control circuit 41 via a wiring. The imaging result (image data) of the imaging unit 73 can be output to the indoor control circuit 41.

The indoor control circuit 41 has a function of detecting a person in the air-conditioned room based on the imaging result of the imaging unit 73. For example, the indoor control circuit 41 extracts the head, chest, wrist, foot, and the like of a person based on image information input from the imaging section 73. The imaging unit 73 detects a person based on the extracted positional relationship of each part. In addition, the above-described method is an example, and the method of detecting a person is not limited thereto. The control unit 40 including the indoor control circuit 41 and the outdoor control circuit 42 performs control for increasing the temperature of the indoor heat exchanger 15 based on the imaging result of the imaging unit 73.

Fig. 15 is a flowchart relating to the cleaning operation of the indoor heat exchanger.

In step S201 in fig. 15, the control unit 40 determines whether or not a kitchen operation or a dining operation is detected.

The "kitchen operation" refers to an operation performed by a person in a room when cooking is performed. When a person in a room cooks in a kitchen, the person is often reciprocated in the lateral direction in the vicinity of the kitchen. Therefore, the control unit 40 determines that the person in the room performs the kitchen operation when, for example, the height position of the head of the person in the room is within a predetermined range (including the average height position of the head when the person stands) and the person in the room moves back and forth in the lateral direction.

On the other hand, the "dining action" refers to an action when the person in the room eats. When a person in a room has a meal, the head is usually kept still in a seated state. Therefore, for example, when the height position of the head of the person in the room is within a predetermined range (including the average height position of the head when the person is seated) and the moving distance of the head of the person in the room is equal to or less than a predetermined value, the control unit 40 determines that the person in the room performs the dining operation.

When the kitchen operation or dining operation is detected in step S201 (yes in S201), the process of the control unit 40 proceeds to step S202. In step S202, the control unit 40 sets the frequency of the cleaning operation of the indoor heat exchanger 15 to be high. That is, the control unit 40 is set to increase the frequency of the cleaning operation during the heating of the indoor heat exchanger 15, as compared with the case where the kitchen operation and the dining operation are not detected.

Next, in step S203, the control unit 40 determines whether or not the cumulative time of the air conditioning operation reaches a predetermined value. That is, the control unit 40 determines whether or not an integrated value (summed value) of the execution times of the integrated air-conditioning operation from the end of the previous cleaning operation reaches a predetermined value. When the cumulative time of the air conditioning operation reaches the predetermined value in step S203 (yes in S203), the process of the control unit 40 proceeds to step S204.

Then, the control unit 40 sequentially performs: heating (S204), freezing (S205), and thawing (S206) of the indoor heat exchanger 15. Note that the processing in steps S204 to S206 is the same as in steps S101 to S103 of the first embodiment (see fig. 5), and therefore description thereof is omitted. On the other hand, in step S203, if the cumulative time of the air conditioning operation does not reach the predetermined value (S203: no), the control unit 40 repeats the process of step S203.

As described above, when the kitchen operation or the dining operation is detected (yes in S201), the control unit 40 causes the cleaning operation to be performed frequently during the heating of the indoor heat exchanger 15 (S202), and the indoor heat exchanger 15 can be brought into a clean state. That is, even if the oil smoke suspended in the air adheres to the indoor heat exchanger 15 during cooking or eating, the oil can be softened by heating of the indoor heat exchanger 15 and can be washed away together with the dust by freezing and thawing.

In step S201, if the kitchen operation and the dining operation are not detected (S201: no), the control unit 40 proceeds to step S203 as intended. In step S203, if the cumulative time of the air conditioning operation reaches the predetermined value (yes in S203), the control unit 40 causes the cleaning operation of the indoor heat exchanger 15 during heating to be performed at a normal frequency.

In addition, regardless of whether the kitchen operation or the dining operation is detected, the cleaning operation (freezing, thawing) without the heating process can be performed appropriately between the current cleaning operation during the heating process of the indoor heat exchanger 15 and the next cleaning operation during the heating process.

< Effect >

According to the fourth embodiment, the control unit 40 performs control to increase the temperature of the indoor heat exchanger 15 based on the imaging result of the imaging unit 73, and then performs freezing of the indoor heat exchanger 15 or the like. Thus, even if oil adheres to the indoor heat exchanger 15 during cooking or eating, the oil is softened by the heating of the indoor heat exchanger 15 and the oil is washed away together with dust. Further, the oil fixedly attached as the oxidation degree increases is softened by heating, and is washed away together with dust by freezing and thawing of the indoor heat exchanger 15.

Fifth embodiment

The fifth embodiment is different from the first embodiment in that a filter cleaning unit 74 (see fig. 16) is provided in an indoor unit 20D (see fig. 16). The fifth embodiment is different from the first embodiment in that the frequency of the cleaning operation during heating of the indoor heat exchanger 15 is lower than the frequency of cleaning the

filters

21a and 21b (see fig. 16). Otherwise, the same as the first embodiment is applied. Therefore, portions different from those of the first embodiment will be described, and redundant description will be omitted.

Fig. 16 is a perspective view of the

filters

21a and 21b and the filter cleaning unit 74 provided in the indoor unit 20D of the air conditioner according to the fifth embodiment.

As shown in fig. 16, the indoor unit 20D includes a movable filter cleaning unit 74 that cleans the

filters

21a and 21b. The filter cleaning unit 74 includes: a frame 74a, a filter cleaning brush 74b, and a filter cleaning motor (not shown).

The frame 74a is in an inverted L shape and is disposed outside the

filters

21a and 21b.

The filter cleaning brush 74b is a brush for removing dust adhering to the

filters

21a and 21b, and is provided inside the frame 74 a.

A filter cleaning motor (not shown) is a driving source for moving the frame 74a in the lateral direction. When the filter cleaning motor is driven, the frame 74a moves in the width direction, and dust on the surfaces of the

filters

21a and 21b is removed by the filter cleaning brush 74 b.

It is preferable that the control unit 40 sets the frequency of the control of increasing the temperature of the indoor heat exchanger 15 (heat exchanger) during the cleaning operation to be lower than the frequency of cleaning the

filters

21a and 21b by the filter cleaning unit 74. By reducing the frequency of heating the indoor heat exchanger 15 in this way, it is possible to reduce discomfort and discomfort to the user when warm air is blown out into the air-conditioning room.

< Effect >

According to the fifth embodiment, the control unit 40 makes the frequency of the cleaning operation during the heating of the indoor heat exchanger 15 lower than the frequency of cleaning the

filters

21a and 21b. This can reduce discomfort and discomfort to the user when warm air is blown into the air-conditioning room.

Sixth embodiment

The sixth embodiment is different from the first embodiment in that heating, freezing, and defrosting of the outdoor heat exchanger 12 are performed sequentially instead of the indoor heat exchanger 15 (see fig. 1). Other points (the structure of the air conditioner, etc., see fig. 1 to 4) are the same as those of the first embodiment. Therefore, description will be given of portions different from those of the first embodiment, and redundant description will be omitted.

Fig. 17 is a flowchart related to a cleaning operation of the outdoor heat exchanger in the air conditioner according to the sixth embodiment (see fig. 1 and 4 as appropriate).

Although omitted in fig. 17, for example, when the integrated value (summed value) of the execution times of the integrated air-conditioning operation from the end of the previous cleaning operation reaches a predetermined value, the series of processing shown in fig. 17 is started. Note that the series of processing shown in fig. 17 may be started when the user operates an operation terminal such as the remote controller 50 (see fig. 4) in a predetermined manner. Depending on the installation environment of the outdoor unit 30 (see fig. 1), oil may adhere to the outdoor heat exchanger 12 in addition to dust.

In step S301, the control unit 40 heats the outdoor heat exchanger 12. That is, the control unit 40 performs control to increase the temperature of the outdoor heat exchanger 12 (heat exchanger) (S301) before performing the process of freezing the outdoor heat exchanger 12 (heat exchanger) (S302). For example, the controller 40 circulates the refrigerant in the refrigeration cycle in the refrigerant circuit 10, and causes the outdoor heat exchanger 12 to function as a condenser.

Preferably, the controller 40 maintains the outdoor heat exchanger 12 at a temperature of 40 ℃ or higher for a predetermined time. Thereby, the oil fixedly attached to the outdoor heat exchanger 12 is heated and softened (or liquefied/fluidized). An outdoor heat exchanger temperature sensor (not shown) for detecting the temperature of the outdoor heat exchanger 12 is provided.

Next, in step S302, the control unit 40 freezes the outdoor heat exchanger 12. That is, the controller 40 circulates the refrigerant in the refrigerant circuit 10 in the heating cycle, causes the outdoor heat exchanger 12 (heat exchanger) to function as an evaporator, and performs a process of freezing the outdoor heat exchanger 12.

Next, in step S303, the controller 40 defrosts the outdoor heat exchanger 12. For example, the controller 40 stops the compressor 11 and increases the opening degree of the expansion valve 14. As a result, the high-temperature refrigerant flows from the high-pressure side indoor heat exchanger 15 into the low-pressure side outdoor heat exchanger 12 through the refrigerant pipe. As a result, frost and ice of the outdoor heat exchanger 12 are melted, and dust is washed away together with the oil.

Fig. 18 is a timing chart showing the opening degree of the expansion valve, the rotation speed of the indoor fan and the outdoor fan, and the temperature change of the outdoor heat exchanger, in addition to the states of the compressor and the four-way valve.

Before the control for heating the outdoor heat exchanger 12 is performed, the cooling operation and the dehumidifying operation may be performed in addition to the heating operation immediately before the air-conditioning operation is stopped.

As shown in fig. 18, at time t1 to t2, the control unit 40 sets the four-way valve 17 in the refrigeration cycle state, throttles the expansion valve 14 to the predetermined opening degree α 1, drives the compressor 11, and causes the outdoor heat exchanger 12 to function as a condenser (S301 in fig. 17). Thereby, the outdoor heat exchanger 12 is heated. During the heating process of the outdoor heat exchanger 12, the controller 40 drives the indoor fan 16 at a low speed and also drives the outdoor fan 13 (fan).

It is preferable that the control unit 40 drives (rotates forward or reversely) the indoor fan 16 at a rotation speed equal to or less than a value calculated by dividing the sum of the upper limit value and the lower limit value of the rotation speed of the indoor fan 16 by 2 during at least a part of the control of increasing the temperature of the outdoor heat exchanger 12. Here, the "lower limit value" means: the control part 40 makes the compressor 11 operate during the air conditioner operationThe lower limit of the rotational speed of the indoor fan 16 during driving. The "lower limit value" does not include the stopped state of the indoor fan 16 (i.e., 0[ min ] ^-1 ]). This can suppress the blowing out of the cooling air into the air-conditioning compartment. In addition, the driving of the outdoor fan 13 can suppress the discharge pressure of the compressor 11 from becoming too high.

The rotational speed of the indoor fan 16 during heating of the outdoor heat exchanger 12 and the rotational speed of the indoor fan 16 during freezing thereafter do not necessarily have to be the same. The same applies to the outdoor fan 13.

After heating the outdoor heat exchanger 12, the control unit 40 switches the four-way valve 17 to the heating cycle (time t 2), throttles the expansion valve 14 to the predetermined opening degree α 2, drives the compressor 11, and causes the outdoor heat exchanger 12 to function as an evaporator (S302 in fig. 17). Thereby, the outdoor heat exchanger 12 is frozen. Further, during freezing of the outdoor heat exchanger 12, the indoor fan 16 and the outdoor fan 13 are driven in a predetermined manner.

After the outdoor heat exchanger 12 is frozen, the controller 40 increases the opening degree of the expansion valve 14 from time t4 to defrost the outdoor heat exchanger 12 (S303 in fig. 17). As a result, the high-temperature refrigerant flows from the high-pressure side indoor heat exchanger 15 into the low-pressure side outdoor heat exchanger 12, thereby melting frost and ice on the outdoor heat exchanger 12 and washing away dust together with oil.

< Effect >

According to the sixth embodiment, the controller 40 performs control to increase the temperature of the outdoor heat exchanger 12 (S301 in fig. 17) to soften the oil adhering to the outdoor heat exchanger 12. The control unit 40 sequentially freezes and unfreezes the outdoor heat exchanger 12 (S302 and S303 in fig. 17). This enables the oil adhering to the outdoor heat exchanger 12 to be washed away together with the dust by the water during freezing. Therefore, the outdoor heat exchanger 12 can be brought into a clean state, and the heat exchange efficiency of the outdoor heat exchanger 12 can be improved.

Seventh embodiment

The seventh embodiment is different from the first embodiment in that the cleaning operation of the indoor heat exchanger 15 and the cleaning operation of the outdoor heat exchanger 12 are performed continuously. Other points (the structure of the air conditioner, etc., see fig. 1 to 4) are the same as those of the first embodiment. Therefore, description will be given of portions different from those of the first embodiment, and redundant description will be omitted.

Fig. 19 is a flowchart related to a cleaning operation of the indoor heat exchanger and the outdoor heat exchanger in the air conditioner according to the seventh embodiment (see fig. 1 and 4 as appropriate).

In step S401, the control unit 40 heats the indoor heat exchanger 15. For example, the controller 40 causes the refrigerant to circulate through the refrigerant circuit 10 in a heating cycle, causes the indoor heat exchanger 15 to function as a condenser, and increases the temperature of the indoor heat exchanger 15. Thereby, the oil on the surface of the indoor heat exchanger 15 is softened.

In step S402, the controller 40 causes the refrigerant to circulate through the refrigerant circuit 10 in the refrigeration cycle, freezes the indoor heat exchanger 15 (evaporator), and heats the outdoor heat exchanger 12 (condenser). Thereby, frost and ice are generated in the indoor heat exchanger 15, while the oil on the surface of the outdoor heat exchanger 12 is softened.

Next, in step S403, the controller 40 causes the refrigerant to circulate through the refrigerant circuit 10 in the heating cycle to thaw the indoor heat exchanger 15 (condenser) and to freeze the outdoor heat exchanger 12 (evaporator). This allows the oil on the surface of the indoor heat exchanger 15 to be washed away together with the dust, while the frost and ice are generated in the outdoor heat exchanger 12.

In step S404, the control unit 40 defrosts the outdoor heat exchanger 12. For example, the controller 40 increases the opening degree of the expansion valve 14, and causes the high-temperature refrigerant to flow from the high-pressure-side indoor heat exchanger 15 into the low-pressure-side outdoor heat exchanger 12. This enables the oil on the surface of the outdoor heat exchanger 12 to be washed away together with the dust. After the process of step S404 is performed, the control unit 40 ENDs a series of processes (END) related to the cleaning operation.

< Effect >

According to the seventh embodiment, the outdoor heat exchanger 12 is also heated during freezing of the indoor heat exchanger 15 (S402 in fig. 19). During defrosting of the indoor heat exchanger 15, the outdoor heat exchanger 12 is also frozen (S403 in fig. 19). This enables both the indoor heat exchanger 15 and the outdoor heat exchanger 12 to be cleaned in a short time, thereby improving user comfort and reducing power consumption of the air conditioner 100 required for a cleaning operation.

Modifications of the examples

The air conditioner 100 and the like of the present invention have been described above with reference to the respective embodiments, but the present invention is not limited thereto and can be variously modified.

For example, although the first embodiment has been described with respect to the case where the control unit 40 freezes the indoor heat exchanger 15 and cleans the indoor heat exchanger 15, condensation may be formed on the indoor heat exchanger 15 instead of this embodiment. Specifically, the control unit 40 first calculates the dew point of the air based on the detected values of the temperature and the humidity of the air-conditioned room. The control unit 40 controls the opening degree and the like of the expansion valve 14 so that the temperature of the indoor heat exchanger 15 is equal to or lower than the dew point and higher than a predetermined freezing temperature. Further, "freezing temperature" means: when the temperature of the indoor heat exchanger 15 is lowered, the temperature at which the moisture contained in the air starts to freeze in the indoor heat exchanger 15. In this way, the indoor heat exchanger 15 can be cleaned by the water in the dew condensation process of the indoor heat exchanger 15.

In addition, in the same manner as in the second to seventh embodiments, the control unit 40 may clean the indoor heat exchanger 15 and/or the outdoor heat exchanger 12 (i.e., the heat exchanger) with the dew condensation water.

In the first embodiment, the case where the control unit 40 drives the indoor fan 16 during the heating of the indoor heat exchanger 15 (time t1 to time t2 in fig. 7) has been described, but the present invention is not limited to this. That is, the control unit 40 may drive the indoor fan 16 (fan) during at least a part of the control for increasing the temperature of the indoor heat exchanger 15 (heat exchanger). This can suppress the discharge pressure of the compressor 11 from becoming too high. The same applies to the seventh embodiment as well as the second to fifth embodiments.

In the sixth and seventh embodiments, the controller 40 may drive the outdoor fan 13 (fan) during at least a part of the control for increasing the temperature of the outdoor heat exchanger 12 (heat exchanger).

In the first embodiment, the case where the controller 40 drives the indoor fan 16 at a low speed in a normal rotation while moving the up-down wind direction plate 24 upward from the horizontal direction during the heating of the indoor heat exchanger 15 (time t1 to time t2 in fig. 7) has been described, but the present invention is not limited to this. That is, the controller 40 may reversely rotate the indoor fan 16 during at least a part of the control of increasing the temperature of the indoor heat exchanger 15. The reverse rotation of the indoor fan 16 is a rotation in the reverse direction to that in the normal air-conditioning operation. This allows air to be blown out to the ceiling through the

air inlets

25a and 25b (see fig. 2), and thus prevents heated air from directly flowing toward the user.

In the first embodiment, the case where the control unit 40 stops the indoor fan 16 during freezing of the indoor heat exchanger 15 (time t3 to time t4 in fig. 7) has been described, but the present invention is not limited to this. That is, the control unit 40 may stop the indoor fan 16 during at least a part of the process of freezing (or condensing) the indoor heat exchanger 15. This can suppress the cool air from being blown out into the air-conditioned room during freezing of the indoor heat exchanger 15. In particular, the control unit 40 preferably stops the indoor fan 16 for a predetermined time from the start of the process of freezing (or condensing) the indoor heat exchanger 15. This can rapidly lower the temperature of the indoor heat exchanger 15, which is heated to a high temperature by heating, and can freeze the indoor heat exchanger 15. Further, the control unit 40 may drive the indoor fan 16 at a low speed (at a rotation speed at which freezing is possible) during freezing of the indoor heat exchanger 15. The same applies to the second to seventh embodiments.

In the first embodiment, the control unit 40 preferably does not perform control for increasing the temperature of the indoor heat exchanger 15 (heat exchanger) when the detection value of the indoor temperature sensor 29 (see fig. 4) or the outdoor temperature sensor 37 (see fig. 4) is equal to or greater than a predetermined value. This prevents the temperature of the air-conditioning room from becoming too high due to the heating of the indoor heat exchanger 15, thereby improving the comfort of the user. The same applies to the second to seventh embodiments.

In the sixth and seventh embodiments, the control unit 40 preferably does not perform control to increase the temperature of the outdoor heat exchanger 12 (heat exchanger) when the detection value of the indoor temperature sensor 29 (see fig. 4) or the outdoor temperature sensor 37 (see fig. 4) is equal to or greater than a predetermined value. This can suppress blowing out of the high-temperature air that has absorbed heat from the indoor heat exchanger 15 (condenser) into the room during freezing after heating in the outdoor heat exchanger 12.

Further, for example, when the detection value of the indoor heat exchanger temperature sensor 33 (heat exchanger temperature sensor, see fig. 4) becomes equal to or greater than a predetermined value during the process of freezing or condensing the indoor heat exchanger 15 (heat exchanger), the control unit 40 preferably starts the above-described process without performing the control of increasing the temperature of the indoor heat exchanger 15. As a specific example thereof, when the integrated value of the execution time of the air conditioning operation reaches a predetermined value from the end of the previous process of freezing the indoor heat exchanger 15 or condensing the dew, or when a command to start the process (freezing of the indoor heat exchanger 15 or the like) is issued from the remote controller 50 (operation terminal), the control unit 40 may start the process such as the freezing of this time without performing the control of increasing the temperature of the indoor heat exchanger 15 when the detection value of the indoor heat exchanger temperature sensor 33 reaches the predetermined value or more. When a command to start a process (e.g., freezing of the indoor heat exchanger 15) is issued from the remote controller 50 (operation terminal), and the detection value of the indoor heat exchanger temperature sensor 33 becomes equal to or greater than a predetermined value within a time range extending back to a predetermined time from the start command, the control unit 40 may start the process such as freezing this time without performing control to increase the temperature of the indoor heat exchanger 15. When freezing or the like of the indoor heat exchanger 15 starts, if the temperature of the indoor heat exchanger 15 is already high (for example, immediately before the heating operation), the indoor heat exchanger 15 does not need to be heated. This can shorten the time required for cleaning the indoor heat exchanger 15, and reduce the power consumption of the air conditioner 100. Similarly, when the detection value of the outdoor heat exchanger temperature sensor (heat exchanger temperature sensor, not shown) is equal to or greater than the predetermined value, the control unit 40 may start the process of freezing or condensing the outdoor heat exchanger 12 without performing the control of increasing the temperature of the outdoor heat exchanger 12.

In the first embodiment, the case where the control unit 40 unfreezes the indoor heat exchanger 15 by fully opening the expansion valve 14 (after time t4 in fig. 7) after freezing the indoor heat exchanger 15 has been described, but the present invention is not limited to this. For example, when the indoor heat exchanger 15 is defrosted, the opening degree of the expansion valve 14 does not have to be increased, and the refrigerant may be allowed to flow through the expansion valve 14. The controller 40 may circulate the refrigerant through the refrigerant circuit 10 in a heating cycle, and may thaw the indoor heat exchanger 15 by causing the indoor heat exchanger 15 to function as a condenser. The control unit 40 may stop the compressor 11 and drive the indoor fan 16 as appropriate to thaw the indoor heat exchanger 15, and the same applies to the second to seventh embodiments.

In the first embodiment, the case where heating, freezing, and thawing of the indoor heat exchanger 15 are sequentially performed as the cleaning operation is described (see fig. 5), but the process of thawing the indoor heat exchanger 15 (S103 in fig. 5) may be omitted. When the indoor heat exchanger 15 is left as it is after freezing, frost and ice in the indoor heat exchanger 15 may be naturally thawed by the heat of the air. The same applies to the second to seventh embodiments.

The embodiments can be appropriately combined. For example, the first embodiment and the second embodiment may be combined, and the control unit 40 may heat the indoor heat exchanger 15 by causing the indoor heat exchanger 15 to function as a condenser (the first embodiment) and energizing the heater 71 (the second embodiment).

For example, the first embodiment and the third embodiment may be combined, and the control unit 40 may heat the indoor heat exchanger 15 by causing the indoor heat exchanger 15 to function as a condenser (the first embodiment) and irradiating ultrasonic waves from the ultrasonic irradiator 72 (the third embodiment). As a heating method of the indoor heat exchanger 15, all of the second to third embodiments may be combined.

For example, the second and third embodiments may be combined with the sixth embodiment. As a heating method of the indoor heat exchanger 15 or the outdoor heat exchanger 12, other methods may be suitably employed.

In the fourth embodiment, the description has been given of the processing (S202) of the control unit 40 for increasing the frequency of the washing operation when detecting the kitchen operation or the dining operation based on the imaging result of the imaging unit 73 (see fig. 13) (yes in S201 of fig. 15), but the present invention is not limited to this. For example, when a thermopile or thermal imaging is used as the "imaging unit", the control unit 40 may increase the frequency of the cleaning operation of the indoor heat exchanger 15 during heating when a heat source (e.g., a fire of a gas furnace) is detected in the air-conditioned room. With this configuration, even if oil during cooking adheres to the indoor heat exchanger 15, the oil is softened by heating of the indoor heat exchanger 15 and the oil is washed away by water during freezing.

Note that, instead of the imaging of the air-conditioned room described in the fourth embodiment, the following processing may be performed. That is, the information on whether or not there is a kitchen or dining may be input based on the user's operation on an "operation terminal" such as a smartphone, a mobile phone, or a tablet pc, in addition to the remote controller 50 (see fig. 4). When a kitchen or dining room is present in the air-conditioning room, the control unit 40 may perform the cleaning operation of the indoor heat exchanger 15 at a high frequency during heating. In this way, the control unit 40 can perform control for increasing the temperature of the indoor heat exchanger 15 based on the operation of the "operation terminal" to bring the indoor heat exchanger 15 into a clean state.

When the user performs a predetermined operation on an "operation terminal" such as a remote controller 50 (see fig. 4), the control unit 40 may perform the cleaning operation of the indoor heat exchanger 15 during heating. For example, if the air conditioner 100 is not used for several months in an intermediate period such as spring or autumn, oil stains may accumulate in the indoor heat exchanger 15. In this case, when the air conditioner 100 is used again in summer and winter, the user can perform the cleaning operation by performing a predetermined operation on the "operation terminal" such as the remote controller 50. This allows oil contamination in the indoor heat exchanger 15 to be washed away.

In the seventh embodiment, the case where the control unit 40 controls heating of the indoor heat exchanger 15 first when the cleaning operation of the indoor heat exchanger 15 and the outdoor heat exchanger 12 is performed (see fig. 19) has been described, but instead of this, only the following process is possible. That is, after performing control to heat the outdoor heat exchanger 12 in a predetermined manner, the controller 40 circulates the refrigerant in the heating cycle to freeze the outdoor heat exchanger 12 (evaporator), and heats the indoor heat exchanger 15 (condenser). The controller 40 circulates the refrigerant in the refrigeration cycle to thaw the outdoor heat exchanger 12 (condenser) and freeze the indoor heat exchanger 15 (evaporator). Next, the controller 40 increases the opening degree of the expansion valve 14, for example, and defrosts the indoor heat exchanger 15. With this process, both the indoor heat exchanger 15 and the outdoor heat exchanger 12 can be cleaned.

In each embodiment, a description has been given of a configuration in which one indoor unit 20 (see fig. 1) and one outdoor unit 30 (see fig. 1) are provided, but the present invention is not limited to this configuration. 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. In addition, the embodiments are also applicable to a whole air conditioner and a building multi-output air conditioner, in addition to a room air conditioner.

The embodiments are described in detail to understand the present invention, but the present invention is not limited to having all of the described configurations. Further, other configurations may be added to or deleted from or replaced with a part of the configurations of the embodiments.

In addition, the above-described mechanisms or structures are shown for illustrative purposes, and not all of the mechanisms or structures need to be present as a product.

Description of the symbols

10-a refrigerant circuit; 11-a compressor; 12-outdoor heat exchanger (heat exchanger); 13-outdoor fans (fans); 14-an expansion valve; 15-indoor heat exchanger (heat exchanger); 16-indoor fans (fans); 17-a four-way valve; 18-a drain pan; 19-a frame body; 21a, 21 b-filters; 29-indoor temperature sensor; 30-an outdoor unit; 33-indoor heat exchanger temperature sensor (heat exchanger temperature sensor); 37-outdoor temperature sensor; 40-a control part; 50-remote controller (operation terminal); 71-a heater; 72-ultrasonic irradiator; 73-an image pickup section; 74-filter cleaning section; 100. 100A, 100B, 100C, an air conditioner.

The claims (modification according to treaty clause 19)

1. (corrected) an air conditioner characterized in that,

comprises a compressor, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger,

and a control unit for performing a cleaning operation of the heat exchanger, which is the indoor heat exchanger or the outdoor heat exchanger,

the control unit increases the temperature of the heat exchanger during the cleaning operation, and then sets the temperature of the heat exchanger to a temperature below freezing point or a temperature below dew point.

2. An air conditioner according to claim 1 (after correction),

the control unit continues a state in which the temperature of the heat exchanger is 40 ℃ or higher for a predetermined time in the control of increasing the temperature of the heat exchanger.

3. An air conditioner according to claim 1 (after correction),

the control unit controls the temperature of the heat exchanger to rise,

the heat exchanger is made to function as a condenser,

a heater provided in the vicinity of the heat exchanger is energized,

or irradiating the heat exchanger with ultrasonic waves from an ultrasonic irradiator.

4. An air conditioner according to claim 1 (after correction),

the control unit starts a process of bringing the heat exchanger to a temperature below freezing point or a temperature below dew point temperature before a predetermined time elapses from the end of the control of raising the temperature of the heat exchanger.

5. An air conditioner according to claim 1 (after correction),

a fan arranged near the heat exchanger,

the control unit drives the fan during at least a part of the control to increase the temperature of the heat exchanger.

6. An air conditioner according to claim 1 (after correction),

the heat exchanger is the indoor heat exchanger,

an indoor fan arranged near the indoor heat exchanger,

the control unit controls the indoor heat exchanger to increase the temperature of the indoor heat exchanger,

the indoor fan is driven in the same direction as that in normal air-conditioning operation and at a rotation speed not more than a value calculated by dividing the sum of the upper limit value and the lower limit value of the rotation speed of the indoor fan by 2,

or the indoor fan is rotated in reverse direction,

the lower limit value is a lower limit value of a rotation speed of the indoor fan when the control unit drives the compressor during an air conditioning operation, and 0[ min ] which is a stop state of the indoor fan is not included in the lower limit value ^-1 ]。

7. An air conditioner according to claim 1 (after correction),

the heat exchanger is the outdoor heat exchanger,

an indoor fan disposed in the vicinity of the indoor heat exchanger,

the control unit drives the indoor fan at a rotation speed equal to or less than a value calculated by dividing the sum of the upper limit value and the lower limit value of the rotation speed of the indoor fan by 2 during at least a part of the control for increasing the temperature of the outdoor heat exchanger,

the lower limit value is a lower limit value of the rotation speed of the indoor fan when the control unit drives the compressor during air conditioning operation, and the lower limit value does not include 0[ min ] which is a stop state of the indoor fan ^-1 ]。

8. An air conditioner according to claim 1 (after correction),

the heat exchanger is the indoor heat exchanger,

the disclosed device is provided with: a heater provided in the vicinity of the indoor heat exchanger; and a drain pan disposed below the indoor heat exchanger,

the control unit energizes the heater after performing a process of bringing the indoor heat exchanger to a temperature below freezing point or a temperature below dew point.

9. An air conditioner according to claim 1 (after correction),

the heat exchanger is the indoor heat exchanger,

the disclosed device is provided with: an image pickup unit that picks up an image of the air-conditioned room; and an operation terminal, which is operated by a user,

the control unit increases the temperature of the indoor heat exchanger based on the result of the image pickup by the image pickup unit or the operation of the operation terminal.

10. An air conditioner according to claim 1 (after correction),

the heat exchanger is the indoor heat exchanger,

the disclosed device is provided with: a filter disposed in the vicinity of the indoor heat exchanger; and a filter cleaning unit for cleaning the filter,

the control unit sets a frequency of control for increasing the temperature of the indoor heat exchanger to be lower than a frequency of cleaning the filter by the filter cleaning unit.

11. An air conditioner according to claim 1 (after correction), comprising:

an indoor temperature sensor that detects a temperature of the air-conditioning room; and

an outdoor temperature sensor which detects the temperature of the outside air,

the control unit does not perform control for increasing the temperature of the heat exchanger when the detection value of the indoor temperature sensor or the outdoor temperature sensor is equal to or greater than a predetermined value.

12. An air conditioner according to claim 1 (after correction),

a heat exchanger temperature sensor for detecting the temperature of the heat exchanger,

when the detected value of the heat exchanger temperature sensor is already equal to or greater than a predetermined value during the cleaning operation, the control unit starts a process of bringing the heat exchanger to a temperature below freezing point or a temperature below dew point without raising the temperature of the heat exchanger.

Statement or declaration (modification according to treaty clause 19)

(1) Claim 1 is defined by the provisions and becomes a new claim 1. The correction is based on the paragraphs [0023], [0033], [0034], [0050], [0090], [0091], [0093], [0104], fig. 5, 7 and 17 in the specification.

(2) The modifications of claim 1 are appropriately made to the modifications of claims 2 to 12.

(3) The inventions according to the appended claims are novel, inventive, and industrially applicable.

Claims

1. An air conditioner characterized in that it comprises a casing,

and a control unit for performing a process of freezing or condensing the heat exchanger, the heat exchanger being the indoor heat exchanger or the outdoor heat exchanger, by causing the heat exchanger to function as an evaporator,

the control part controls the temperature of the heat exchanger to rise before the treatment.

2. The air conditioner according to claim 1,

the control unit continues the state in which the temperature of the heat exchanger is 40 ℃ or higher for a predetermined time in the control for increasing the temperature of the heat exchanger.

3. An air conditioner according to claim 1,

the control unit, in the control for increasing the temperature of the heat exchanger,

the heat exchanger is made to function as a condenser,

a heater provided in the vicinity of the heat exchanger is energized,

4. An air conditioner according to claim 1,

the control unit starts the process of freezing or condensing the heat exchanger before a predetermined time elapses from the end of the control of raising the temperature of the heat exchanger.

5. An air conditioner according to claim 1,

a fan arranged near the heat exchanger,

the control unit drives the fan during at least a part of the control for increasing the temperature of the heat exchanger.

6. An air conditioner according to claim 1,

the heat exchanger is the indoor heat exchanger,

an indoor fan disposed in the vicinity of the indoor heat exchanger,

the control unit increases the temperature of the indoor heat exchanger during at least a part of the control,

or the indoor fan is rotated in reverse direction,

7. The air conditioner according to claim 1,

the heat exchanger is the outdoor heat exchanger,

an indoor fan disposed in the vicinity of the indoor heat exchanger,

8. An air conditioner according to claim 1,

the heat exchanger is the indoor heat exchanger,

the disclosed device is provided with: a heater disposed in the vicinity of the indoor heat exchanger; and a drain pan disposed below the indoor heat exchanger,

the control unit energizes the heater after the process of freezing or condensing the indoor heat exchanger is performed.

9. An air conditioner according to claim 1,

the heat exchanger is the indoor heat exchanger,

the control unit performs the control of increasing the temperature of the indoor heat exchanger based on the imaging result of the imaging unit or the operation of the operation terminal.

10. An air conditioner according to claim 1,

the heat exchanger is the indoor heat exchanger,

the control unit sets a frequency of the control for increasing the temperature of the indoor heat exchanger to be lower than a frequency of cleaning the filter by the filter cleaning unit.

11. An air conditioner according to claim 1, comprising:

an outdoor temperature sensor which detects the temperature of the outside air,

the control unit does not perform the control of increasing the temperature of the heat exchanger when a detection value of the indoor temperature sensor or the outdoor temperature sensor is equal to or greater than a predetermined value.

12. An air conditioner according to claim 1,

the control unit starts the process without performing the control of increasing the temperature of the heat exchanger when the detection value of the heat exchanger temperature sensor is already equal to or greater than a predetermined value in the case of performing the process of freezing or condensing the heat exchanger.