JP7513486B2 - Method for cleaning air conditioner and indoor heat exchanger - Google Patents

Description

The present invention relates to a cleaning technology for cleaning indoor heat exchangers in air conditioners.

Air conditioners with cooling and dehumidifying functions are known to have a cleaning function for the indoor heat exchanger. Patent Document 1 discloses a technology as a conventional technique for an air conditioner with a cleaning function for the indoor heat exchanger.

As shown in Patent Document 1, an air conditioner has a control unit that, when it receives a signal to stop operation of the air conditioner and then a signal to start cleaning, starts cleaning a predetermined time after the operation stop signal is received.

To clean the indoor heat exchanger, first the temperature of the refrigerant flowing through the indoor heat exchanger is lowered, causing the moisture near the fins that make up the indoor heat exchanger to freeze. Next, warm refrigerant is passed through the indoor heat exchanger and air is blown over it. The moisture near the fins is melted into water, which is then used to wash away dust and other particles that have accumulated in the indoor heat exchanger.

By starting cleaning a specified time after receiving the operation stop signal, it is possible to ensure that the operator who performed these operations has time to go outside. As described above, cleaning the indoor heat exchanger not only cools or warms the indoor heat exchanger, but also blows air. This makes it possible to more reliably prevent the operator from being exposed to air at an unintended temperature, improving comfort.

Patent No. 6314294

However, even between the time when operation is stopped and the time when cleaning starts, refrigerant flows into the indoor heat exchanger from the outdoor unit due to convection and other factors. When cooling or dehumidifying operation is performed, the refrigerant temperature on the outdoor unit side is high, so the temperature of the refrigerant flowing into the indoor heat exchanger while operation is stopped is high. For this reason, the temperature of the refrigerant flowing through the indoor heat exchanger gradually increases after operation is stopped. For this reason, if the specified time until cleaning starts is set long, a long time is required to cool the indoor heat exchanger again. On the other hand, if the specified time until cleaning starts is set short, there is not enough time available for the operator to go outside.

The objective of the present invention is to provide a technology that can recool the indoor heat exchanger in a short time when cleaning starts.

According to one aspect of the present invention, there is provided an air conditioner having a compressor that compresses a refrigerant, a condenser that cools the refrigerant compressed in the compressor, an expansion valve that reduces the pressure of the refrigerant cooled in the condenser, an indoor heat exchanger through which the refrigerant that has been made low-temperature and low-pressure in the expansion valve flows and capable of cooling indoor air by heat exchange, and a control unit that is capable of controlling the compressor and the expansion valve,
In an air conditioner capable of cleaning the indoor heat exchanger by receiving a cleaning start signal after receiving an operation stop signal by the control unit,
The air conditioning device is provided such that, when the control unit receives the cleaning start signal after receiving the operation stop signal, it controls the compressor and the expansion valve so that it operates the compressor a predetermined time after receiving the operation stop signal and starts cleaning by opening the expansion valve which is in a fully closed state.

According to another aspect of the present invention, there is provided a method for cleaning an indoor heat exchanger of an air conditioner, the method comprising the steps of:
Detecting a signal to stop a cooling operation or a dehumidification operation;
starting to measure an operation stop time after detecting the operation stop signal;
detecting a cleaning start signal for the indoor heat exchanger after detecting the operation stop signal;
a step of determining whether or not an operation stop time is within a preset predetermined time when the cleaning start signal is detected;
and opening the fully closed expansion valve to a predetermined degree when the predetermined time has elapsed, and starting cleaning of the indoor heat exchanger.

The present invention provides a technology that can recool the indoor heat exchanger in a short time when cleaning begins.

1 is a schematic diagram of an air conditioner according to an embodiment; FIG. 2 is a block diagram of the air conditioning device shown in FIG. 1 . FIG. 2 is a flow chart illustrating a method for cleaning the indoor heat exchanger shown in FIG. 1 . FIG. 4 is a flow diagram illustrating a modified example of the method for cleaning the indoor heat exchanger shown in FIG. 3 .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the accompanying drawings.
<Example>

Please refer to FIG. 1. FIG. 1 shows an air conditioner 10 according to the present invention. The air conditioner 10 has a cooling function for cooling the indoors In, a heating function for heating, and a dehumidification function for dehumidifying. The air conditioner 10 has at least either the cooling function or the dehumidification function.

The air conditioner 10 comprises an outdoor unit 20 installed outdoors (Ou) and an indoor unit 30 installed indoors (In). The outdoor unit 20 and the indoor unit 30 are connected to each other so that the refrigerant can circulate. In the following, unless otherwise specified, the direction in which the refrigerant circulates is based on the cooling operation.

The outdoor unit 20 has a four-way switching valve 21 that switches the direction of refrigerant circulation during cooling, heating, and dehumidification operations, a compressor 22 through which the refrigerant that has passed through the four-way switching valve 21 flows and compresses the refrigerant, a condenser 23 through which the refrigerant that has been compressed in the compressor 22 and has become high temperature and high pressure flows, an outdoor fan 24 that blows air toward the condenser 23, and an expansion valve 25 that reduces the pressure of the refrigerant that has passed through the condenser 23.

The indoor unit 30 is used indoors In by hanging it on a wall Wa. The indoor unit 30 is housed in a case 31 fixed to the wall Wa, an indoor heat exchanger 32 through which low-temperature, low-pressure refrigerant that has passed through the expansion valve 25 flows, and an indoor fan 33 that blows air to the indoor heat exchanger 32.

An air intake 31a is provided at the top of the case 31 to take in air. An air outlet 31b is provided at the bottom front of the case 31 to blow air indoors In. The air outlet 31b can be opened and closed by a louver 35 that is swingably supported on the case 31.

The air conditioner 10 further has a remote control 13 for switching operation on and off and starting and stopping cleaning of the indoor heat exchanger 32. The remote control 13 has a power switch 13a for switching operation on and off and a cleaning switch 13b for instructing the start and stop of cleaning. The remote control 13 is operated by the operator.

Refer to Figure 2. The air conditioner 10 has a control unit 15 that receives electrical signals when the power switch 13a or the cleaning switch 13b is operated, and controls the compressor 22, the indoor fan 33, the louver 35, and the expansion valve 25. The control unit 15 is an arithmetic and logic circuit that has a CPU, ROM, RAM, etc.

The air conditioner 10 also has a timer 16 that measures the time the operation is stopped after receiving an electrical signal to stop operation. The timer 16 starts measuring time upon receiving an electrical signal from the control unit 15. The control unit 15 may also open and close the expansion valve 25 based on the electrical signal from the timer 16. Details will be described later.

See Figure 1. During cooling operation, the refrigerant that has been heated to a high temperature and pressure by the compressor 22 exchanges heat with outside air in the condenser 23, releasing heat. At this time, the outdoor fan 24 operates to force the outside air to flow around the periphery of the condenser 23, promoting heat exchange. The refrigerant that has passed through the condenser 23 and released heat is depressurized in the expansion valve 25, and its temperature drops. The cooled refrigerant is sent to the indoor heat exchanger 32.

When the indoor fan 33 is operated, air is introduced into the case 40 from the air intake 31a of the indoor unit 30. The introduced air passes around the periphery of the indoor heat exchanger 34 and is blown into the indoor space In from the air outlet 31b. The indoor heat exchanger 34 is supplied with refrigerant that has been cooled in the outdoor unit 20. The air passing around the periphery of the indoor heat exchanger 34 exchanges heat with the refrigerant and is cooled. As a result, cooled air is blown into the indoor space In.

During heating operation, the four-way switching valve 21 switches the refrigerant flow path, circulating the refrigerant in the opposite direction to that during cooling operation. Next, an example of a method for cleaning the indoor heat exchanger 32 will be described.

See Figures 2 and 3. When the operator operates the power switch 13a during cooling or dehumidification (hereinafter referred to as "cooling, etc.") operation, the air conditioner 10 stops operation. When the power switch 13a is operated, an operation signal is sent to the control unit 15. When the control unit 15 detects a signal (operation stop signal) indicating the end of cooling, etc. operation (ST01), it stops the compressor 22 and the indoor fan 33, closes the louvers 35, and starts the timer 16 to start counting the operation stop time (ST02).

Next, the operator operates the cleaning switch 13b, and the control unit 15 detects an electrical signal (cleaning start signal) to start cleaning. When the control unit 15 receives an instruction to start cleaning (ST03), the control unit 15 receives information about the operation stop time from the timer and determines whether the operation stop time is within a predetermined time (ST04). The predetermined time is a time that is assumed to be sufficient for the operator to leave the indoors In (see Figure 1), and is set to, for example, 3 minutes.

If the operation stop time is within the predetermined time, the control unit 15 closes the expansion valve 25 (ST05). By closing the expansion valve 25, the flow of refrigerant from the outdoor unit 20 (see FIG. 1) to the indoor heat exchanger 32 (see FIG. 1) is blocked.

After the expansion valve 25 is closed and a predetermined time has elapsed (ST06), the control unit 15 operates the compressor 22 and the indoor fan 33 at a predetermined rotation speed, opens the louvers 35 and the expansion valve 25 to a predetermined opening degree (ST07), and cleans the indoor heat exchanger 32.

The predetermined rotation speeds of the compressor 22 and the indoor fan 33, and the predetermined openings of the louvers 35 and the expansion valve 25 in ST07 are preset values for cleaning the indoor heat exchanger 32 (see FIG. 1). These values may be changed as appropriate over time.

In ST07, the control unit 15 may fully open the expansion valve 25 before operating the compressor 22, and may open the expansion valve 25 to a predetermined degree after the compressor 22 is operated.

In ST04, the operation stop time may exceed a predetermined time. In this case, the control unit 15 operates the compressor 22 and the indoor fan 33 at a predetermined rotation speed without closing the expansion valve 25, and opens the louver 35 and the expansion valve 25 to a predetermined opening degree (ST07).

To clean the indoor heat exchanger 32, first, a low-temperature refrigerant is passed through the interior of the indoor heat exchanger 32 to condense the moisture around the indoor heat exchanger 32 onto the fins of the indoor heat exchanger 32, and then air is blown through the indoor heat exchanger 32 to wash away the condensed water and any dust that has adhered to it. This cleans the indoor heat exchanger 32.

Next, a modified example will be described. In the modified example, the timing for fully closing the expansion valve is different from the example described in FIG. 3. Even in the modified example, the structure of the air conditioner 10 is basically the same. A method for cleaning the indoor heat exchanger in the modified example will be described.

See Figures 2 and 3. When the operator operates the power switch 13a during cooling or other operation, the air conditioner 10 stops operation. When the power switch 13a is operated, an operation signal is sent to the control unit 15. When the control unit 15 detects a signal to end cooling or other operation (operation stop signal) (ST11), it stops the compressor 22 and indoor fan 33, closes the louver 35 and expansion valve 25, and starts the timer 16 to start counting the operation stop time (ST12).

Next, the operator operates the cleaning switch 13b, and the control unit 15 detects an electrical signal (cleaning start signal) to start cleaning. When the control unit 15 receives an instruction to start cleaning (ST13), the control unit 15 receives information about the operation stop time from the timer and determines whether the operation stop time is within a predetermined time (ST14). The predetermined time is a time that is assumed to be sufficient for the operator to leave the indoors In (see Figure 1), and is set to, for example, 3 minutes.

If the operation stop time is within the predetermined time, the process waits for the predetermined time to elapse (ST16). Since the expansion valve 25 is closed in ST12, the flow of refrigerant from the outdoor unit 20 (see FIG. 1) to the indoor heat exchanger 32 (see FIG. 1) is blocked.

After a predetermined time has elapsed (ST16), the control unit 15 operates the compressor 22 and the indoor fan 33 at a predetermined rotation speed, opens the louvers 35 and the expansion valve 25 to a predetermined opening degree (ST17), and cleans the indoor heat exchanger 32.

In ST17, the control unit 15 may fully open the expansion valve 25 before operating the compressor 22, and may open the expansion valve 25 to a predetermined degree after the compressor 22 is operated.

In ST14, it may happen that the operation stop time exceeds a predetermined time. In this case, the control unit 15 operates the compressor 22 and the indoor fan 33 at a predetermined rotation speed, and opens the louver 35 and the expansion valve 25 to a predetermined opening degree (ST17).

To clean the indoor heat exchanger 32, first, a low-temperature refrigerant is passed through the interior of the indoor heat exchanger 32 to condense the moisture around the indoor heat exchanger 32 onto the fins of the indoor heat exchanger 32, and then air is blown through the indoor heat exchanger 32 to wash away the condensed water and any dust that has adhered to it. This cleans the indoor heat exchanger 32.

Even if there is no instruction to start cleaning in ST13, the control unit 15 receives information on the operation stop time from the timer and determines whether the operation stop time is within a predetermined time (ST18). If it is within the predetermined time, the process returns to ST13.

In ST18, if the operation shutdown time exceeds the predetermined time, the expansion valve 25 is opened to a predetermined opening degree to complete the operation shutdown procedure.

The present invention is summarized below.

See Figures 1 to 3. If the time between receiving the operation stop signal and receiving the cleaning start signal is less than or equal to a predetermined time, the control unit 15 fully closes the expansion valve 25 until the predetermined time is reached. On the other hand, if the predetermined time is exceeded, the expansion valve 25 is opened and the compressor 22 is operated to start cleaning. Cleaning is performed by first cooling the indoor heat exchanger 32 and condensing moisture adhering to the fins, etc. At this time, by keeping the expansion valve 25 fully closed until just before cleaning, it is possible to prevent warm refrigerant from the outside from flowing into the indoor heat exchanger 32 and causing the temperature of the indoor heat exchanger 32 to rise. Therefore, the indoor heat exchanger 32 can be recooled in a short time when cleaning starts.

Furthermore, when the control unit 15 receives a cleaning start signal, it can control the compressor 22 and the expansion valve 25 to fully open the expansion valve 25 before operating the compressor 22, and to open the expansion valve 25 to a predetermined degree once the compressor 22 is operating. When the expansion valve 25 is fully open, the refrigerant can flow more easily than when it is closed to a certain degree. When the compressor 22 is operating, a large load is applied to the compressor 22, so by fully opening the expansion valve 25, the load on the compressor 22 can be reduced. This contributes to a longer life for the compressor 22.

In addition, when the control unit 15 receives a cleaning start signal, it can fully close the expansion valve 25 if the time between receiving the operation stop signal and receiving the cleaning start signal is less than a predetermined time. By fully closing the expansion valve 25 when the predetermined time is less than or equal to the time, it is possible to prevent the efficiency of the cleaning operation from decreasing due to the high-temperature, high-pressure refrigerant in the condenser 23 flowing into the indoor heat exchanger 32 immediately after the operation is stopped, and if the predetermined time is exceeded, the expansion valve is opened because the refrigerant temperature in the condenser 23 has dropped to a certain extent, and the load on the compressor and other components in the refrigeration cycle is reduced by prioritizing pressure equalization, which averages the pressure in the refrigeration cycle (the refrigerant circuit formed by the compressor → four-way valve → condenser → expansion valve → indoor heat exchanger → compressor, etc.).

On the other hand, the control unit 15 can also fully close the expansion valve 25 by receiving an operation stop signal. Since the expansion valve 25 is immediately closed after operation is stopped, the refrigerant temperature can be further prevented from rising, and the indoor heat exchanger 32 can be recooled in a short time, especially when cleaning starts.

The air conditioner of the present invention is suitable for use as a home air conditioner.

REFERENCE SIGNS LIST 10: Air conditioner 15: Control unit 22: Compressor 23: Condenser 32: Indoor heat exchanger

Claims (5)

a compressor for compressing a refrigerant, a condenser for cooling the refrigerant compressed in the compressor, an expansion valve for reducing the pressure of the refrigerant cooled in the condenser, an indoor heat exchanger into which the refrigerant that has been made low-temperature and low-pressure in the expansion valve flows and which is capable of cooling indoor air by heat exchange, and a control unit capable of controlling the compressor and the expansion valve;
In an air conditioner capable of cleaning the indoor heat exchanger by receiving a cleaning start signal after receiving an operation stop signal by the control unit,
The control unit of the air conditioning device controls the compressor and the expansion valve so that, when it receives the cleaning start signal after receiving the operation stop signal, and if the time between receiving the operation stop signal and receiving the cleaning start signal is less than a predetermined time, it fully closes the expansion valve, operates the compressor after a predetermined time has elapsed after receiving the operation stop signal, and starts cleaning by opening the expansion valve which is in a fully closed state. The air conditioner according to claim 1, wherein the control unit is capable of controlling the compressor and the expansion valve so that, when a cleaning start signal is received, the expansion valve is fully opened before the compressor is operated, and the expansion valve is opened to a predetermined degree when the compressor is operated. a compressor for compressing a refrigerant, a condenser for cooling the refrigerant compressed in the compressor, an expansion valve for reducing the pressure of the refrigerant cooled in the condenser, an indoor heat exchanger into which the refrigerant that has been made low-temperature and low-pressure in the expansion valve flows and which is capable of cooling indoor air by heat exchange, and a control unit capable of controlling the compressor and the expansion valve;
In an air conditioner capable of cleaning the indoor heat exchanger by receiving a cleaning start signal after receiving an operation stop signal by the control unit,
The control unit of the air conditioning apparatus controls the compressor and the expansion valve so that, upon receiving the operation stop signal, the expansion valve is fully closed, and if the cleaning start signal is received after receiving the operation stop signal, the control unit operates the compressor a predetermined time after receiving the operation stop signal and starts cleaning by opening the expansion valve which is in a fully closed state . A method for cleaning an indoor heat exchanger of an air conditioner, comprising:
Detecting a signal to stop a cooling operation or a dehumidification operation;
starting to measure an operation stop time after detecting the operation stop signal;
detecting a cleaning start signal for the indoor heat exchanger after detecting the operation stop signal;
a step of determining whether or not an operation stop time is within a preset predetermined time when the cleaning start signal is detected;
closing the expansion valve if the operation stop time is equal to or shorter than the predetermined time as a result of determining whether the operation stop time is within the predetermined time;
and opening the expansion valve, which is in a fully closed state, to a predetermined degree when the predetermined time has elapsed, and starting cleaning of the indoor heat exchanger. 5. The method for cleaning an indoor heat exchanger according to claim 4 , wherein, when starting cleaning of the indoor heat exchanger, the expansion valve is fully opened prior to operation of the compressor, and the expansion valve is opened to a predetermined degree when the compressor is operated.

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