JP2000297958A - Air conditioner - Google Patents

Abstract

(57) [Summary] [Problem] To suppress frequent stoppage of a compressor to prevent freezing. An air conditioner counts the number of times the compressor is stopped in order to prevent freezing.
While the value is less than 1, the temperature Ta, which is the return temperature when the stop of the compressor is released, is set to the lowest temperature Ta1 (steps 272 and 276). When the count value exceeds C1, the temperature is raised to Ta2 and the maintenance is performed. The lamp is turned on (steps 274, 278, 280). Further, when the count value exceeds C2, the temperature Ta is raised to the temperature Ta3, thereby delaying the stop release and making the compressor hard to stop. When the count value exceeds C3, the return of the compressor is not released. (Step 274,
282-288).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for controlling indoor air.

[0002]

2. Description of the Related Art For example, in an air conditioner (hereinafter referred to as an "air conditioner") for circulating a refrigerant between a heat exchanger provided in an indoor unit and a compressor provided in an outdoor unit for air conditioning in a room, When the indoor air sucked in by operating the cross flow fan is passed through the heat exchanger, heat is exchanged with the refrigerant.

On the other hand, in an air conditioner, a filter is provided in an indoor unit to remove dust and dirt from the air sucked into the indoor unit. When the filter becomes clogged, the amount of air blows decreases. The desired cooling capacity cannot be obtained. For this reason, the air conditioner uses a display such as a filter sign to prompt maintenance such as cleaning or replacement of the filter based on the operation time or the like.

In an air conditioner, when a cooling operation is being performed, the temperature of the heat exchanger is set to a predetermined temperature (for example, approximately equal to the temperature at which water freezes) in order to prevent freezing due to a decrease in temperature of the heat exchanger. (0.8 ° C.), the compressor is shut down to prevent the temperature of the heat exchanger from dropping below this temperature. In an air conditioner, if the compressor is stopped to prevent freezing, a predetermined time (for example, 3
Minutes), leave the compressor off
When the temperature of the heat exchanger rises to a predetermined temperature (for example, about 8 ° C.), the compressor is restarted and the cooling operation is started.

[0005]

However, when the compressor is stopped by the anti-freezing function, the air is continuously blown and the operation / stop of the compressor by the anti-freezing function is stopped.
It is not felt by people in the room. On the other hand, if the temperature of the heat exchanger becomes excessively low as well as the filter is clogged, the freezing prevention function is frequently activated in the air conditioner, and the operation / stop of the compressor is repeated.

Air conditioners include a so-called inverter type in which the operating capacity is controlled by changing the operating frequency of the compressor, in addition to a type in which the operating capacity is controlled by operating / stopping the compressor. , The operation / stop of the compressor is rarely repeated, and the frequent operation / stop of the compressor means that some abnormality has occurred,
It is necessary to consider that anomalies may occur.

[0007] The present invention has been made in view of the above facts, the compressor is frequently turned on / off by the anti-freezing function.
It is an object of the present invention to propose an air conditioner that suppresses turning off and prevents occurrence of abnormality due to frequent turning on / off of a compressor.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a method in which a refrigerant circulating in a refrigeration cycle by a compressor driven at a rotational speed corresponding to a required cooling capacity is used to generate air in a heat exchanger. An air conditioner that cools a room by cooling the air conditioner, wherein a temperature detecting means for detecting a temperature of a heat exchanger, and a drive of the compressor when a temperature detected by the temperature detecting means reaches a stop temperature. Stop means for stopping the compressor, return means for enabling the operation of the compressor by the temperature detected by the temperature detection means after the compressor is stopped by the stop means reaches the return temperature, the compressor of the compressor by the stop means Counting means for counting the number of stops, and temperature setting for correcting the return temperature based on the count value of the counting means Characterized in that it comprises a stage, a.

According to the present invention, when controlling the cooling capacity by controlling the rotation speed of the compressor, the compressor is stopped when the temperature of the heat exchanger detected by the temperature detecting means reaches a predetermined temperature, Prevent freezing due to excessively low temperature of the heat exchanger. The stop of the compressor is released when the temperature of the heat exchanger reaches a return temperature set higher than the stop temperature.

On the other hand, the counting means counts the number of times the compressor is stopped by the stopping means, and corrects the return temperature based on the count value, for example, by increasing the return temperature.
Thereby, it is possible to prevent the compressor from frequently stopping to prevent the freezing of the heat exchanger.

Further, the present invention includes integrating means for integrating the operating time in the cooling mode, wherein the temperature setting means increases the return temperature based on the count value of the counting means and the integrated time of the integrating means. It is characterized by making it.

According to this invention, the integrating means integrates the cooling operation time, and based on the integrated time and the count value of the counting means, determines the return temperature when the stop of the compressor is repeated during a relatively short operating time. To raise.

Thus, even if the stopping means repeatedly stops the compressor, the stopping frequency can be reduced, and the occurrence of an abnormality due to the repeated stopping of the compressor can be prevented.

In the present invention, it is preferable to increase the return temperature stepwise. Further, when the stop frequency of the compressor decreases or when the stop means does not operate for a predetermined time or more, the return temperature is reduced stepwise so as to reach a predetermined temperature which is set in advance, or a predetermined predetermined temperature is set. It is preferred to return to temperature.

Further, the present invention is characterized by including a notifying means for notifying that the stop frequency of the compressor is increasing based on the integrated value of the operation time and the count value of the number of stops.

According to the present invention, when the compressor is frequently stopped by the stopping means, the stopping of the compressor is reported by the reporting means. When controlling the number of revolutions of the compressor according to the required cooling capacity, the stopping means rarely operates frequently. For this reason, by notifying by the notification means when the stopping means operates frequently, inspection can be encouraged, and occurrence and propagation of abnormalities can be suppressed.

As such a notifying means, an alarm or the like may be used as long as the air conditioner operation is stopped because the return of the compressor is greatly delayed. It is preferable to notify by lighting or blinking.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 2 shows a refrigeration cycle of an air conditioner (hereinafter, referred to as “air conditioner 10”) applied to the present embodiment.

The air conditioner 10 includes an indoor unit 12 installed in a room to be air-conditioned and an outdoor unit 1 installed outside the room.
The indoor unit 12 and the outdoor unit 14 are formed by a thick refrigerant pipe 16 for circulating a refrigerant.
A and the refrigerant pipe 16B of a thin tube.

The indoor unit 12 is provided with a heat exchanger 18, and one end of each of the refrigerant pipes 16A and 16B is connected to the heat exchanger 18. The other end of the refrigerant pipe 16A is connected to a valve 20A of the outdoor unit 14. The valve 20A is connected to a four-way valve 24 via a muffler 22A, and the four-way valve 24 is connected to a compressor 26 via an accumulator 28 and via a muffler 22B.

Further, the outdoor unit 14 is provided with a heat exchanger 30. One end of the heat exchanger 30 is connected to the four-way valve 24 and the other end is connected to the capillary tube 32.
The strainer 34, the electric expansion valve 36, and the modulator 38 are connected to the valve 20B. This valve 20
The other end of the refrigerant pipe 16B is connected to B, thereby forming a closed circulation path of the refrigerant forming a refrigeration cycle between the indoor unit 12 and the outdoor unit 14.

In the air conditioner 10, when the compressor 26 is operated, the refrigerant circulates through the refrigeration cycle. In FIG. 2, arrows indicate the flows of the refrigerant during the heating operation (heating mode) and during the cooling operation (cooling mode or dry mode), and the operation mode is changed to the cooling mode (including the dry mode) by switching the four-way valve 24. And the heating mode are switched, and by controlling the valve opening of the electric expansion valve 36, the evaporation temperature of the refrigerant is adjusted. Note that the present invention can be applied to an air conditioner having an arbitrary configuration, and the air conditioner 10 shows one example.

As shown in FIG. 3, the indoor unit 12
The heat exchanger 18 is provided in a casing 42 in which an inlet 48 and an outlet 50 are formed. The casing 42 is fixed to a wall surface or the like of the room to be air-conditioned by the base plate 40.

Inside the casing 42, the heat exchanger 18
A cross flow fan 44 and a filter 46 are arranged between the suction port 48 and the suction port 48, and the air in the room is sucked into the casing 42 by the operation of the cross flow fan 44,
After passing through the filter 46 and the heat exchanger 18, the air is blown into the room from the air outlet 50. When the air sucked into the casing 42 passes through the heat exchanger 18, heat is exchanged with the refrigerant circulated in the heat exchanger 18,
It becomes the temperature-controlled air (air-conditioned wind) that air-conditions the room.

The filter 46 filters out dust and dirt in the room air sucked through the suction port 48. This prevents dust or air mixed with dust from being blown out from the outlet 50 of the indoor unit 22 as conditioned air.

The outlet 50 of the indoor unit 12 is provided with upper and lower flaps 54 together with left and right flaps 52, and the direction of the conditioned air blown out from the outlet 50 is changed by the left and right flaps 52 and the upper and lower flaps 54. The air conditioner 10 controls the directions of the left and right flaps 52 and the upper and lower flaps 54 so that
The air-conditioning air can be blown from any direction to any direction.

As shown in FIG. 4, the indoor unit 12
Is provided with a power supply board 56, a control board 58, and a power relay board 60. On a power supply board 56 to which electric power for operating the air conditioner 10 is supplied, a motor power supply 62, a control circuit power supply 64, a serial power supply 66, and a drive circuit 68 are provided. The control board 58 is provided with a serial circuit 70, a drive circuit 72, and a microcomputer 74.

A drive motor 68 (for example, a DC brushless motor) for driving the cross flow fan 44 is connected to a drive circuit 68 of the power supply board 56, and receives a control signal from a microcomputer 74 provided on the control board 58. Drive power is supplied from the motor power supply 62 accordingly. At this time, the microcomputer 74 controls so that the output voltage from the drive circuit 68 is changed in a range of 12 V to 36 V in 256 steps. Thus, the amount of the conditioned air blown out from the outlet 50 of the indoor unit 12 is adjusted.

The drive circuit 72 of the control board 58 is connected to an upper and lower flap motor 78 for operating the power relay board 60 and the upper and lower flaps 54. The power relay board 60 is provided with a power relay 80, a temperature fuse, and the like. The power relay 80 is operated by a signal from the microcomputer 74 to open and close a contact 80A for supplying power to the outdoor unit 14. Air conditioner 1
0 indicates that power can be supplied to the outdoor unit 14 by closing the contact 80A.

The upper and lower flap motor 78 includes a microcomputer 74
, The upper and lower flaps 54 can be operated to blow conditioned air toward a desired area.

The air conditioner 10 includes a cross flow fan 44
Is controlled and the operation of the upper and lower flaps 54 is controlled to blow out air conditioned air at a desired air flow rate and direction or a controlled air flow rate and air direction to make the room comfortable. In the air conditioner 10, the left and right flaps 52 are manually operated. However, as an air conditioner to which the present invention is applied, the left and right flaps 52 may be operated using a flap motor. .

The microcomputer 74 and a serial circuit 70 connected to the serial power supply 66 of the power supply circuit 56 are connected to the outdoor unit 14. The microcomputer 74 communicates with the outdoor unit 14 via the serial circuit 70. Serial communication is performed to control the operation of the outdoor unit 14.

The microcomputer 74 is connected to a room temperature sensor 84 for detecting the room temperature and a heat exchange temperature sensor 86 for detecting the coil temperature of the heat exchanger 18. A service LED provided on the control board 58 is also provided. And an operation changeover switch 88 are connected. The operation changeover switch 88 switches between “normal operation” and “test operation” performed at the time of maintenance or the like, and “stop” that opens the contact of the power switch 88A and shuts off supply of operation power to the air conditioner 10. Can be Normally, the operation changeover switch 88
Is set to "normal operation" and the contact of the power switch 88A is closed. The service LED is turned on at the time of maintenance to notify a service person of a self-diagnosis result.

The indoor unit 12 includes an outdoor unit 14
There is provided a terminal block 90 to which wiring is connected. Wirings for power supply from the indoor unit 12 to the outdoor unit 14 and wiring for performing serial communication between the indoor unit 12 and the outdoor unit 14 are connected to the terminals 90A, 90B, 90C of the terminal block 90. .

The air conditioner 10 includes a remote control switch 120
When an operation signal corresponding to the switch operation is received, the operation signal is read into the microcomputer 74. Microcomputer 74
Is configured to set operation conditions such as an operation mode and air-conditioning capacity based on the read operation signal, and perform air-conditioning operation based on the set operation conditions. Note that a general configuration in which the rotation speed of the compressor 26 is controlled by serial communication with the indoor unit 12 or the like can be used as the outdoor unit 14, and a detailed description thereof will be omitted in the present embodiment.

On the other hand, the indoor unit 12 is provided with a receiving circuit for receiving an operation signal from the remote control switch 120 (see FIG. 1), and a display board 82 provided with an operation display LED and the like. The board 82 is the microcomputer 7
4 is connected. The display substrate 82 is provided with a display panel 94 together with a receiving unit that receives an operation signal from the remote control switch 120.

As shown in FIG. 1, the casing 42 of the air conditioner 10 is provided with a display panel 94,
The operation state of the air conditioner 10 is displayed on the display panel 94. As shown in FIG. 5, the display panel 94 includes:
An operation lamp 96 that is turned on in response to operation / stop of the air conditioner 10, a timer display lamp 98 that is turned on when a timer operation such as an on-timer operation or an off-timer operation is set,
A maintenance lamp 102 is provided along with a filter lamp 100 that indicates whether or not the time for replacing the filter 46 has been reached.

As the operation lamp 96, the timer display lamp 98, and the filter lamp 100, LEDs that emit light of a predetermined color are used. The filter lamp 1
As 00, for example, a light-emitting element that emits green and red is provided integrally, and emits yellow in addition to green and red, and emits yellow when the timing of replacement or cleaning of the filter 46 approaches. Is also good.

The microcomputer 74 provided on the control board 58 controls the operation lamp 9 while the air conditioner 10 is operating.
6 is turned on, and the timer operation is set by operating the remote control switch 120.
8 is turned on.

The microcomputer 74 accumulates the operation time of the air conditioner 10 regardless of the cooling, dry and heating modes, turns on a filter lamp according to the accumulated operation time, and replaces or cleans the filter 46. Encourage maintenance such as. As shown in FIG. 5, a reset button 104 is provided on the display panel 94, and after performing maintenance such as replacement or cleaning of the filter 46, the reset button 104 is operated to reset the accumulated time. And the filter lamp 100 is turned off.

The air conditioner 10 has a heat exchanger 1
8 is provided with an anti-freezing function for preventing the temperature from excessively lowering. The maintenance lamp 102 is turned on in response to the operation of the anti-freezing function to indicate that the air conditioner 10 needs maintenance. Like that.

FIG. 6 shows that the control board 5 is controlled by the microcomputer 74 of the indoor unit 12 to prevent freezing.
8 shows a schematic configuration of an antifreezing mechanism 130 configured on the upper surface 8.

The anti-freezing mechanism 130 detects the coil temperature T-c of the heat exchanger 18 detected by the heat exchange temperature sensor 86.
A coil temperature detecting unit 132 for detecting oil and a capacity limiting unit 134 for limiting the rotation speed of the compressor 26 according to the temperature detected by the coil temperature detecting unit 132 are provided. The capacity limiting unit 134 is a compressor 26 configured by a microcomputer or an inverter in the outdoor unit 14.
The operation of the drive unit 135 of the (compressor motor) is restricted.

That is, as shown in FIG.
When the coil temperature T-coil reaches a predetermined temperature Ta (for example, 8.0 ° C.), the capacity limiting unit 134 prohibits an increase in the operating frequency of the compressor 26 set according to the cooling capacity or reduces the operating frequency. Thereby, the cooling capacity is suppressed, and when the coil temperature T-coil decreases and reaches a predetermined temperature Tb (for example, 0.8 ° C.) near the temperature at which water freezes, the operating frequency of the compressor 26 is set to 0 Hz. The compressor 26 is stopped.

The capacity limiting section 134 stops the compressor 26 for a predetermined time (for example, 3 minutes), and thereafter, the coil temperature T-coil rises to a predetermined temperature Ta (for example, a set temperature of 8.0 ° C. or more). Then, the operation restriction of the compressor 26 is released. Thereby, in the air conditioner 10, the compressor 26 according to the operating frequency based on the set temperature or the like is used.
Operation is resumed.

That is, as shown in FIG.
When the coil temperature T-coil drops to the temperature Ta, the capacity limiting unit 134 starts to limit the operating frequency of the compressor 26 (restriction zone). If the coil temperature T-coil still drops and reaches the temperature Tb, The compressor 26 is stopped (stop zone). When the compressor 26 stops, the capacity limiting unit 134 prohibits the driving of the compressor 26 until the coil temperature Tb exceeds the temperature Ta.

For example, as shown in FIG. 7 (B), in the air conditioner 10, the temperature Ta is usually set to 8.0 ° C., the temperature Tb is set to 0.8 ° C., and furthermore, according to the coil temperature T-coil. Thus, the restriction zone is divided into an upper ban zone in which an increase in the operating frequency of the compressor 26 is prohibited, a hertz down zone in which the operating frequency of the compressor 26 is gradually lowered, and the hertz down zone is divided.

Thus, in the air conditioner 10, if the coil temperature T-coil is equal to or higher than the temperature Ta (T-coil> 8.0), normal control of the compressor 26 is performed, and
During 5.6 ° C. (8.0 ≧ T-coil <5.6), the operating frequency of the compressor 26 is prohibited from increasing, and the coil temperature T-coil is set to 5.6 ° C. to 1.6 ° C. (5.6 ≦ T-co
During il <1.6), the coil temperature T-coil is prevented from lowering by performing a Hertz down operation that gradually lowers the operating frequency of the compressor 26. Further, in the air conditioner 10, when the operating frequency of the compressor 26 becomes 0 Hz due to the hertz down, and the coil temperature T-coil is not less than a fixed time (for example, 2 minutes) and not more than 1.6 ° C.
≦ T-coil <0.8), the coil temperature T-coi
The compressor 26 is stopped even when l is 0.8 ° C. or more.

When the compressor 26 is stopped,
After a certain time (for example, 3 minutes) has elapsed, the compressor 2
6 is released, and when the coil temperature T-coil exceeds 8.0 ° C., normal operation becomes possible after operation (mask processing) while limiting the operation frequency of the compressor 26. , Freeze prevention is stopped.

On the other hand, as shown in FIG. 6, the anti-freezing mechanism 130 has a counting section 136 for counting the number of times the capacity limiting section 134 has stopped the compressor 26, and a cooling operation time integrating section for integrating the cooling operation time. 138 and an antifreeze control unit 140 are provided, and the maintenance lamp 102 is connected to the antifreeze control unit 140.

The anti-freezing control unit 140 includes the counting unit 13
When it is determined that the compressor 26 is stopped frequently to prevent freezing based on the number of stoppages of the compressor 26 counted by 6 and the operation time accumulated by the cooling operation time accumulation unit 138, the compressor 26 is driven. Is changed to a higher value of the temperature Ta for restarting the operation. Thereby, the time until the compressor 26 resumes the operation is extended, and the compressor 26 is prevented from being repeatedly turned on / off frequently.

The anti-freezing control unit 140 determines the temperature Ta
Compressor 2 to prevent freezing frequently
6 is repeated, the maintenance lamp 102
Is turned on to encourage maintenance.

The operation of this embodiment will now be described with reference to FIGS.
This will be described with reference to the flowchart shown in FIG.

FIG. 8 shows the processing executed by the capacity limiting unit 134.
The outline of the freeze prevention control for stopping the compressor 26 based on the coil temperature T-coil of the heat exchanger 18 is shown. Note that this flowchart may be executed regardless of the operation mode when the air conditioner 10 is operated, or may be executed in the cooling mode and the dry mode in which the temperature of the heat exchanger 18 decreases. Good. Also,
This flowchart ends when the air conditioner 10 stops operating.

First step 20 of this flowchart
At 0, the coil temperature T-coil detected by the heat exchange temperature sensor 86 is read, and at the next step 202, it is confirmed whether or not the coil temperature T-coil has dropped to a temperature Ta (for example, 8.0 ° C.).

Here, when the coil temperature T-coil of the heat exchanger 18 drops to the temperature Ta due to a decrease in the amount of air passing through the heat exchanger 18 due to clogging of the filter 26 or the like, at step 202 When the determination is affirmative, the process proceeds to step 204. As a result, regardless of the setting of the operating frequency of the compressor 26, an increase in the operating frequency of the compressor 26 is prohibited or an operation restriction is made to gradually lower the operating frequency. Note that, in the air conditioner 10, this operation restriction is set in FIG.
(B) and the coil temperature T-coil, and a detailed description is omitted.

Thereafter, at step 206, the coil temperature T-coil is read, and at step 208, it is confirmed whether or not the coil temperature T-coil has exceeded the temperature Ta.
In step 210, it is confirmed whether or not the coil temperature T-coil has further decreased to the temperature Tb.

In the air conditioner 10, the cooling capacity is reduced by lowering the operating frequency of the compressor 26.
The coil temperature T-coil of the heat exchanger 18 also increases. Therefore, by controlling the operating frequency of the compressor 26 to be reduced, the coil temperature T-coil exceeds the temperature Ta,
If an affirmative determination is made in step 208, the process proceeds to step 212, where the restriction on the operating frequency of the compressor 26 is released.

On the other hand, if an unsuitable state such as a decrease in the amount of air passing through the heat exchanger 18 due to clogging or the like of the filter 46 occurs, the compressor 2
Despite limiting the operating frequency of 6, the coil temperature T-coil drops further.

Thus, the coil temperature T of the heat exchanger 18
If -coil reaches the temperature Tb (for example, 0.8 ° C.) and the determination in step 210 is affirmative, the process proceeds to step 214 to stop the compressor 26.

In the air conditioner 10, since the circulation of the refrigerant to the heat exchanger 18 is stopped by stopping the compressor 26, the coil temperature T-coil of the heat exchanger 18 does not fall below this temperature Tb. The freezing of the heat exchanger 18 due to the coil temperature T-coil falling below the temperature Tb is prevented.

Thereafter, in step 216, it is confirmed whether or not a predetermined time (for example, three minutes) has elapsed since the compressor 26 was stopped. That is, the air conditioner 1
At 0, when the compressor 26 is stopped due to freezing prevention or the like, the operation start of the compressor 26 is prohibited for a predetermined time.

When a predetermined time has elapsed since the compressor 26 was stopped, and a positive determination is made in step 216, the process proceeds to step 218, where the coil temperature T-coil is read.
In step 220, it is confirmed whether or not the coil temperature T-coil has risen to a preset temperature Ta. As a result, if the coil temperature T-coil exceeds the temperature Ta and an affirmative determination is made in step 220, the process proceeds to step 222, where the return process of the compressor 26 is started. Is resumed.

In the air conditioner 10, any conventionally known control method can be used as the return process. For example, during a predetermined time (for example, six minutes), the upper limit of the operating frequency of the compressor 26 is set based on the number of revolutions of the cross flow fan 44 and the like, so that the coil temperature T-coil is not lowered and the coil temperature is reduced. Mask processing such as interrupting the control of the compressor 26 based on the temperature T-coil is performed.

As described above, by performing the anti-freezing control, it is possible to reliably prevent the freezing due to the coil temperature T-coil of the heat exchanger 18 being too low. In addition,
Any method can be used to prevent freezing.

On the other hand, a freezing prevention mechanism 130 provided in the air conditioner 10 prevents freezing and manages the freezing prevention processing. 9 and 10 show an example of the management of the freeze prevention process.

FIG. 9 shows an accumulation routine for freezing prevention.
It is confirmed whether or not the operation has been started in the cooling or the dry mode. When the operation of the air conditioner 10 is started in the cooling or the dry mode, an affirmative determination is made in step 230 and the execution is started.

In the next step 232, initialization is performed, and in step 234, it is confirmed whether or not to continue the integration. That is, in this flowchart, normally, the integrated time t of the cooling operation and the compressor 2
The count value C of the number of stop times of No. 6 is carried over, and when the previous process is continued, the previous integrated time t and the count value C are read and set in the initial setting. Note that the following description is based on the assumption that the accumulated time t and the count value C have been reset (t = 0, C = 0) and the previous processing is not continued.

Accordingly, if a negative determination is made in step 234, the process proceeds to step 236 to determine whether or not the compressor 26 has stopped to prevent freezing.
Check whether has stopped. In step 238, it is checked whether the air conditioner 10 stops operating.
In addition, there is no stop of the compressor 26 due to the prevention of freezing,
When the operation of the air conditioner 10 ends (step 23)
In step 240, the final accumulation status is stored for the next processing.

Here, the compressor 2 is used to prevent freezing.
6 is stopped, and if an affirmative determination is made in step 236, the process proceeds to step 242, where the integration timer is reset / started to start integration of the integration time t, and the count value C is set to “1” in step 244. Set to set (C = 1). As a result, the operation time of the air conditioner 10 in the cooling or dry mode after the compressor 26 is first stopped due to freezing prevention and the counting of the number of times the compressor 26 is stopped are started.

When the process is continued from the integration status at the time of the previous operation, an affirmative determination is made in step 234 when the air conditioner 10 starts the cooling operation, and the process proceeds to step 246, whereby the integration timer is started. It is restarted from the time of the end of the previous processing. Further, in the present embodiment, the timer is started after the first compressor 26 is stopped.
When starting the cooling operation of 0, a timer may be started.

In the next step 248, it is confirmed whether or not the compressor 26 has stopped due to the prevention of freezing. If the compressor 26 has stopped, and if the determination in step 248 is affirmative, the process proceeds to step 250 to stop the compressor 26. The count value C of the number of times is incremented (counted up). At the same time, in the next step 252, management processing based on freeze prevention described later is performed.

Until the compressor 26 stops due to freezing prevention, a negative determination is made in step 248, so that the integrated time t and the count value C are reset. In this reset processing, for example, it is determined whether or not a predetermined time has elapsed since the previous stop of the compressor 26 in step 254, and when the predetermined time has elapsed (a positive determination is made in step 254), the process proceeds to step 256. do it,
The stop frequency of the compressor 26 is calculated from the accumulated time t and the count value C, and it is confirmed whether or not the frequency calculated in step 258 is low.

Here, for example, if one hour or more has elapsed since the last stop of the compressor 26 and the stop frequency of the compressor 26 is about once every hour, the compressor stop frequency is determined to be low and a negative determination is made in step 258. I do. Accordingly, by moving to step 260, the timer for integration is stopped, and the count value C of the number of stops is cleared (C = 0). The stop frequency may be arbitrarily set as long as it can be determined that the air conditioner 10 is operating normally.

On the other hand, if the stop frequency is not low, the process proceeds to step 262 to check whether or not the operation of the air conditioner 10 has been stopped. If the cooling operation of the air conditioner 10 has been stopped (YES at step 262). )
The routine proceeds to step 240, where the accumulated time t and the count value C are stored, and this flowchart is terminated.

As described above, by operating the air conditioner 10 in the cooling or dry mode, the operation time in the cooling or dry mode is integrated, and the count of the number of times the compressor 26 is stopped based on the coil temperature T-coil is continued. Do it.

FIG. 10 shows an example of management processing executed each time the compressor 26 is stopped. This flowchart is executed every time the process proceeds to step 252 in the flowchart of FIG. 9, and in the first step 270, it is confirmed whether or not the stopped compressor 26 has been restarted.

Here, when the compressor 26 is restarted, in steps 272 and 274, the count value C of the number of times the compressor 26 has been stopped is confirmed. In the present embodiment, when the number of stops is less than 5 (C1 = 5), the temperature Ta as the return temperature is set to 8.0 ° C. (Ta1 = 8.0), but the number of stops exceeds 5 times. And the temperature Ta were changed to 10 ° C. (Ta2 = 10), and the number of stops was 10 (C2 =
If the temperature exceeds 10), the temperature Ta is changed to 12 ° C (Ta3 =
12). Further, if the number of stops exceeds 12 (C3 = 12), the restart of the compressor 26 is prohibited when the compressor 26 is stopped next time.

Thus, if the count value C of the number of stops of the compressor 26 is less than C1, an affirmative determination is made in step 272, and the routine proceeds to step 276, where the return temperature Ta is changed to the normal temperature Ta1 (8.0). ° C)
Next, when the compressor 26 is stopped, the coil temperature T
When -coil reaches this temperature Ta1, the compressor 26 is restarted.

On the other hand, when the number of stops of the compressor 26 reaches five, a negative determination is made in step 272, a positive determination is made in the next step 274, and the routine proceeds to step 278. In this step 278, the temperature Ta is changed to the temperature Ta1.
A higher temperature Ta2 (10 ° C.) is set. In step 280, the maintenance lamp 102 is turned on.

As a result, the maintenance lamp 102 provided on the display panel 94 of the indoor unit 12 is turned on, and the compressor 26 for preventing the heat exchanger 18 from freezing.
Is frequently stopped, and it is displayed that the maintenance of the air conditioner 10 is necessary.

When the compressor 26 is stopped next time, the return temperature rises, so that the time until the stop of the compressor 26 is released is extended. Therefore, even when the coil temperature T-coil of the heat exchanger 18 is too low, the interval at which the compressor 26 stops is extended.

If the coil temperature T-coil of the heat exchanger 18 drops too much despite the increase in the temperature Ta, the compressor 26 stops. The stop of the compressor 26 is further repeated, and when the count value C reaches ten times, a negative determination is made in step 274 and the process proceeds to step 282.

In step 282, the temperature Ta is set to the temperature Ta3, and the maintenance lamp 102 is continuously turned on (step 284). As a result, the return temperature is further increased, and the time until the stop of the compressor 26 is released is further extended.

As described above, in the air conditioner 10, as the number of times the compressor 26 is stopped to prevent freezing increases, the temperature T-coil, which is the return temperature when the stop of the compressor 26 is released, is increased stepwise. By doing so, the interval when the ON / OFF of the compressor 26 is repeated is extended, and the ON / OFF of the compressor 26 in a short time is prevented.

On the other hand, although the temperature Ta is raised, the coil temperature T-coil of the heat exchanger 18 is too low, the compressor 26 is stopped, and the count value C becomes 12 (C3
= 12), an affirmative determination is made in step 286, and the flow proceeds to step 288. In this step 288, when the compressor 26 is stopped next time, restart of the compressor 26 is prohibited. Thereby, when the compressor 26 is stopped next due to the coil temperature T-coil falling too much, the stop of the compressor 26 is set not to be released.

That is, in the air conditioner 10, although the temperature Ta is raised, the compressor 26 is turned on / off.
When the turning-off is repeated frequently, it is determined that it is difficult to normally perform the cooling operation due to clogging of the filter 46, and the cooling operation is stopped.

Thus, the air conditioner 10 prevents the heat exchanger 18 from freezing when the operating frequency of the compressor 26 is changed in accordance with the cooling capacity by gradually increasing the temperature Ta which is the return temperature. Of the compressor 26 for a short time is prevented from being repeated in a short time. In the air conditioner 10, when the number of stoppages of the compressor 26 becomes too large and exceeds a predetermined number,
By leaving the compressor 26 stopped,
It is possible to prevent the occurrence of secondary abnormalities such as defective components due to repeated ON / OFF of the compressor 26.

The above-described embodiment does not limit the configuration of the present invention. For example, the temperatures Ta and Tb, which are the return temperatures, can be set arbitrarily within a range where an appropriate air-conditioning operation can be performed.
The number of stops of the compressor 26 and the temperature rise when the pressure is increased stepwise can be arbitrarily set.

In this embodiment, the compressor 2
When the number of stops of C6 exceeds C3, the stop of the compressor 26 is not released, but the temperature Ta may be further increased.

In this embodiment, the maintenance lamp 102 is lit to notify that maintenance is required. However, when the number of stops is relatively small, the maintenance lamp 102 is turned on and off, and the number of stops is reduced. The number of times the compressor 26 is stopped and the degree of urgency may be displayed in accordance with the state of blinking of the maintenance lamp, such as turning on the maintenance lamp 102 when the number increases, and stopping the compressor 26. When it is no longer possible, an alarm or the like may be further provided.

In the present embodiment, the air conditioner 10 that performs cooling and heating by a refrigeration cycle has been described as an example.
The air conditioner to which the present invention is applied may be a cooling-only air conditioner that performs a cooling operation by a refrigeration cycle, or performs a cooling operation by a refrigeration cycle and circulates hot water to an indoor unit. A so-called hot-water type air conditioner or the like that performs heating in this manner may be used.

[0093]

As described above, according to the present invention, when the compressor is stopped to prevent freezing of the heat exchanger during the cooling operation, the stop of the compressor is released according to the number of times the compressor is stopped. By raising the return temperature, an excellent effect that frequent repetition of stopping / releasing the compressor while performing the cooling operation can be suppressed can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an indoor unit of an air conditioner applied to the present embodiment.

FIG. 2 is a schematic configuration diagram illustrating a refrigeration cycle of the air conditioner.

FIG. 3 is a schematic configuration diagram showing an indoor unit.

FIG. 4 is a block diagram illustrating a schematic configuration of an electric circuit of the indoor unit.

FIG. 5 is a schematic diagram illustrating an example of a display panel provided in an indoor unit.

FIG. 6 is a block diagram illustrating a schematic configuration of a freeze prevention mechanism provided in the indoor unit.

FIG. 7A is a diagram schematically illustrating a control region of a compressor according to a coil temperature, and FIG. 7B is a schematic diagram of a control region of a compressor according to a coil temperature of an air conditioner applied to the present embodiment. FIG.

FIG. 8 is a flowchart showing an outline of freeze prevention.

FIG. 9 is a flowchart showing an example of counting the number of stops due to freezing prevention and integrating the operation time.

FIG. 10 is a flowchart illustrating an example of changing a return temperature according to the number of stops.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Air conditioner 12 Indoor unit 18 Heat exchanger 26 Compressor 58 Control board 74 Microcomputer 86 Heat exchange temperature sensor (Temperature detection means) 94 Display panel 102 Maintenance lamp (Announcement means) 130 Freezing prevention mechanism 132 Coil temperature detection part (Temperature detection means) 134 Capacity limiting unit (stopping unit, return unit) 136 Counting unit (counting unit) 138 Cooling operation time integrating unit (integrating unit) 140 Freezing prevention control unit (temperature setting unit)

Claims (3)

[Claims] 1. An air conditioner for cooling a room by cooling air in a heat exchanger with a refrigerant circulating in a refrigeration cycle by a compressor driven at a rotation speed according to a required cooling capacity. Temperature detecting means for detecting the temperature of the heat exchanger; stopping means for stopping driving of the compressor when the temperature detected by the temperature detecting means reaches a stop temperature; and stopping the compressor by the stopping means. Return means for enabling the operation of the compressor when the temperature detected by the temperature detection means reaches the return temperature, and counting means for counting the number of times the compressor is stopped by the stopping means; and a count value of the counting means. Temperature setting means for correcting the return temperature on the basis of: 2. The method according to claim 1, further comprising: integrating means for integrating the operation time in the cooling mode, wherein the temperature setting means increases the return temperature based on the count value of the counting means and the integrated time of the integrating means. The air conditioner according to claim 1, wherein 3. A notifying means for notifying that the stop frequency of the compressor is high based on the integrated value of the operation time and the count value of the number of stop times. 3. The air conditioner according to any one of 2.