JPH0743051A - Air conditioner - Google Patents

Abstract

PURPOSE:To provide an air conditioner in which the drop of the room temperature can be suppressed to a low extent by shortening the defrosting time, i.e., the suspension time of heating. CONSTITUTION:The temperature of an outdoor heat exchanger 6 is detected by first temperature detecting means 11. The temperature of the atmosphere in which an outdoor unit is installed is detected by second temperature detecting means 12. A controller 10 has a fan stopping defrosting function of stopping an outdoor fan during a heating mode operation of a refrigerating cycle to defrost the outdoor heat exchanger, and a fan operating defrosting function of defrosting the outdoor heat exchanger while the outdoor fan remains operated. When the atmospheric temperature at the time of starting defrosting is a predetermined value or less, the fan stopping defrosting is executed, and when the atmospheric temperature exceeds the predetermined value, the fan operating defrosting is executed. And, at the time of at least the fan operating defrosting, the defrosting is finished according to the defrost finishing reference temperature so set as to become higher when the atmospheric temperature is higher.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a split type air conditioner, and more particularly to defrost control of an outdoor heat exchanger.

[0002]

2. Description of the Related Art An air conditioner of this type includes a compressor, a four-way valve, an indoor heat exchanger, an expansion valve and an outdoor heat exchanger, which are connected to form a refrigeration cycle, and an indoor space for promoting heat exchange. It has a fan and an outdoor fan. this house,
The indoor heat exchanger and the indoor fan are stored as an indoor unit, and the compressor, the four-way valve, the expansion valve, the outdoor heat exchanger, and the outdoor fan are stored as an outdoor unit.

When the outside air temperature when the air conditioner is operated in the heating mode is low, frost adheres to the outdoor heat exchanger.
When this frost becomes thick, the heat exchange efficiency decreases, and the air conditioning capacity significantly decreases. Therefore, the refrigeration cycle is operated in the defrosting mode in order to melt and remove the frost. In the defrosting mode, as shown in FIG. 13, with the compressor still operating,
From the time t ₁ at which the temperature of the outdoor heat exchanger has reached the defrost start reference temperature to the time t ₁₁ where the temperature of the outdoor heat exchanger rises to defrost termination criterion temperature, by stopping the energization of the four-way valve, The refrigeration cycle is operated in the cooling mode by reversing the circulation path of the refrigerant. At this time, the indoor fan is stopped to prevent the room temperature from dropping due to the blowing of cold air, and the outdoor fan is also stopped to suppress the cooling of the outdoor heat exchanger due to the supply of cold outside air.

Thus, when the refrigeration cycle is operated in the defrosting mode, the temperature of the outdoor heat exchanger changes as shown in FIG. That is, when frost adheres to the outdoor heat exchanger and starts defrosting at time t _{1 when the} temperature has dropped to the defrosting start reference temperature, the temperature rises and is maintained at a value slightly higher than 0 ° C. during melting of frost. , As soon as all the frost is thawed, the temperature rises suddenly, so the defrosting is terminated at time t _{11 when the} temperature reaches the defrosting termination reference temperature.

[0005]

During the defrosting mode operation,
Since the indoor fan is stopped, no cold air is blown out, but the room temperature still falls significantly below the set temperature. In order to keep this temperature drop small, the defrosting operation time must be shortened. In the defrosting mode operation described above, the pipe that circulates the refrigerant is warmed, the fins are warmed by the conduction heat from this pipe to defrost the frost, and the output of the temperature sensor that makes contact with the pipe determines whether defrosting has occurred. I made a decision based on this. However, the conventional air conditioner requires a certain amount of time for the pipe to warm up, and the defrosting end reference temperature is set high because it indirectly determines the end of defrosting from the temperature of the pipe. There is a problem that the operation time in the defrosting mode becomes long because it is unavoidable.

The present invention has been made in order to solve the above problems, and shortens the defrosting operation time, that is, the interruption time of the heating operation, thereby reducing the decrease in room temperature. The purpose is to obtain the device.

[0007]

An air conditioner according to claim 1 comprises a first temperature detecting means for detecting the temperature of the outdoor heat exchanger, and a second temperature detecting means for detecting the outside air temperature.
Fan stop function that defrosts the outdoor heat exchanger by stopping the outdoor fan during heating mode operation of the refrigeration cycle, and fan operation that defrosts the outdoor heat exchanger while the outdoor fan is operating. With the function of defrosting, when the outside air temperature at the start of defrosting is below a predetermined value, fan stop defrosting is executed,
When the outside air temperature exceeds a predetermined value, fan operation defrosting is executed, and during this fan operation defrosting, the defrosting is finished according to the defrosting end reference temperature that is set to be higher when the outside air temperature is higher. And a device.

Further, the air conditioner according to claim 2 is
First temperature detecting means for detecting the temperature of the outdoor heat exchanger,
Second temperature detecting means for detecting the outside air temperature, a function for stopping the outdoor fan to defrost the outdoor heat exchanger during the heating mode operation of the refrigeration cycle, and a function for defrosting the outdoor fan, and operating the outdoor fan. It has a function of fan operation defrosting to defrost the outdoor heat exchanger as it is, and when the outside air temperature at the start of defrosting is below a prescribed value, fan defrosting is executed and the outside air temperature falls to a prescribed value. When the temperature exceeds, the fan operation defrosting is performed for the set time, then the fan stop defrosting is performed, and at the time of this fan stop defrosting, the defrosting end reference temperature is set to become lower as the outside air temperature becomes higher. And a control device for ending the defrosting according to the above.

Preferably, the time for performing fan operation defrosting is set longer as the outside air temperature is higher.

The first defrosting start is determined based on the temperature of the outdoor heat exchanger, and the second and subsequent defrosting starting points are the temperature of the outdoor heat exchanger and the heating operation after the last defrosting is finished. Judge based on the duration.

[0011]

In a general outdoor heat exchanger, as shown in a perspective view in FIG. 15 (a) and a side view during frost formation in FIG. 15 (b), many outdoor heat exchangers are provided around the pipe 61 for circulating the refrigerant. The fins 62 are welded at predetermined intervals. Frost adheres to the fins 62. That is, it is frosted. Defrosting is started when the detection value of the temperature sensor 11 brought into contact with the pipe 61 drops to a preset defrosting start reference temperature, and defrosting ends when the detection value rises to the defrosting end reference temperature.

If the outside air temperature during frost formation is high, the fan is operated to blow air to the outdoor heat exchanger,
Defrosting can be performed before the pipe 61 is warmed up. Further, defrosting can be promoted even after the pipe 61 has warmed up. However, if the blast continues to be blown even after the frost has melted, the fins 62 warmed by the refrigerant will be cooled, and the temperature of the outdoor heat exchanger tends to approach the outdoor temperature. That is, the temperature of the outdoor heat exchanger at the end of defrosting is higher as the outside air temperature is higher, and is lower as the outside air temperature is lower. Therefore, in order to shorten the defrosting time, it is convenient to use the defrosting termination reference temperature that is set to be higher as the outside air temperature is higher.

Therefore, in the air conditioner according to the first aspect, the fan stop defrosting is executed when the outside air temperature at the start of defrosting is below a predetermined value, and the fan operation is performed when the outside air temperature exceeds the predetermined value. Defrosting is performed, and at least at the time of fan operation defrosting, the defrosting is terminated according to the defrosting termination reference temperature that is set to be higher when the outside air temperature is higher. Thereby, the defrosting operation time can be shortened.

On the other hand, when the fan operation defrosting is executed, the blowing of the outdoor fan greatly contributes to the melting of the frost on the peripheral side portion A of the fin 62 shown in FIG. Frost in the near center B is mainly melted by the high temperature refrigerant passing through the pipe 61. Therefore, if the outdoor fan continues to be operated until the defrosting ends, the blown air has a cooling effect on the defrosting of the central portion B. In this sense, it is desirable to switch from fan operation defrost to fan stop defrost during defrosting. In this way, even if you switch from fan operation defrost to fan stop defrost,
When the outside air temperature is high, the defrosting ends even if the temperature of the pipe is low because the effect of ventilation before switching is large, but when the outside air temperature is low, the defrosting must be done until the pipe temperature rises to some extent. Will not end. Therefore, in order to shorten the defrosting time, it is necessary to lower the defrosting termination reference temperature as the outside air temperature is higher.

Therefore, the air conditioner according to a second aspect of the invention performs fan stop defrosting when the outside air temperature at the start of defrosting is below a predetermined value, and is set when the outside air temperature exceeds the predetermined value. After the fan operation defrosting is executed for a certain period of time, the fan defrosting is performed, and the defrosting is ended according to the defrosting end reference temperature set to be lower as the outside air temperature is higher. This also makes it possible to shorten the defrosting operation time.

The absolute amount of frost adhering to the outdoor heat exchanger varies depending on the outside air temperature. For example, when the outside air temperature is higher than 0 ° C, it is large, and when it is lower than 0 ° C, it is small. Therefore, when performing fan stop defrost after performing fan operation defrost, by increasing the fan operation defrost time when the outside air temperature is high and shortening the fan operation defrost time when the outside air temperature is low, The control effect of performing fan stop defrosting after performing fan operation defrosting can be enhanced.

Therefore, in the air conditioner according to a third aspect of the present invention, the fan operation defrosting time is set longer as the outside air temperature is higher.

By the way, the state in which the outdoor heat exchanger requires defrosting is also a state in which the heating capacity is significantly reduced. As one method of detecting this state, the temperature of the outdoor heat exchanger is detected, and the temperature is lowered to the reference temperature. However, the decline in heating capacity began long before it fell to the reference temperature. If this decrease in heating capacity is measured, defrosting may be started at that point. However, since the heating capacity itself is not simple to measure, it can be said that the temperature of the outdoor heat exchanger is used for convenience. If the air conditioning load does not change significantly, the temperature change of the outdoor heat exchanger after defrosting should show a constant tendency regardless of the number of defrosting cycles. Therefore, the second and subsequent defrosting may be determined based on the elapsed time from the end of the previous defrosting. When the judgment is made based on the elapsed time, it may be the time when the heating capacity is slightly reduced. Even when determining the decrease in heating capacity based on the elapsed time, it must be taken into consideration that the initial defrosting start reference temperature may be reached before that due to a sudden change in weather.

Therefore, in the air conditioner according to the fourth aspect, the first defrosting start point is determined based on the temperature of the outdoor heat exchanger, and the second and subsequent defrosting start points are subjected to the outdoor heat exchange. Judgment is made based on the temperature of the heater or the duration of heating operation after the last defrosting.

[0020]

The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 is a schematic configuration diagram of an embodiment of the present invention. In the figure, a well-known refrigeration cycle is formed by the compressor 1, the four-way valve 2, the indoor heat exchanger 3, the expansion device 5, and the outdoor heat exchanger 6, and the heat exchange of the indoor heat exchanger 3 is promoted. An indoor fan 4 and an outdoor fan 7 are provided to accelerate heat exchange of the outdoor heat exchanger 6. Of these, the indoor heat exchanger 3 and the indoor fan 4
Is stored in the indoor unit, and the compressor 1, the four-way valve 2, the expansion device 5, the outdoor heat exchanger 6, and the outdoor fan 7 are stored in the outdoor unit.

Here, when the four-way valve 2 is energized, the refrigerant is circulated in the direction shown by the solid line arrow to bring the refrigeration cycle into the heating mode. By being circulated in the direction indicated by, the refrigeration cycle enters the cooling mode.

If the operation is continued in the heating mode when the outside air temperature is low, frost adheres to the outdoor heat exchanger 6. In order to remove this frost, a control device 10 consisting of a microcomputer
And a temperature sensor 11 for detecting the temperature of the outdoor heat exchanger 6,
A temperature sensor (12) for detecting the outside air temperature of the outdoor unit is provided. The controller 10 controls the compressor 1, the four-way valve 2, the indoor fan 4, and the outdoor fan 7 based on the temperature detected by the temperature sensor 11 for the outdoor heat exchanger 6 and the temperature detected by the temperature sensor 12 for the outside air.

In this embodiment, as shown in FIG. 2, the indoor fan is heated at time t _{1 when} the temperature of the outdoor heat exchanger 6 detected by the temperature sensor 11 has dropped to a predetermined defrosting start reference temperature. 4 is stopped and the connection state of the four-way valve 2 is switched to temporarily set the refrigeration cycle to the defrosting mode (cooling mode), but when the outside air temperature is high to some extent, the outdoor fan 7 is continuously operated. As a result, the heat quantity of the outside air is effectively used for defrosting. Then, at time t _{2 when} the temperature of the outdoor heat exchanger 6 reaches the defrosting termination reference temperature, the connection state of the four-way valve 2 is restored and the refrigeration cycle is returned to the heating mode.

When the four-way valve 2 is switched and connected at the time t ₂ when the defrosting operation is switched to the heating operation, the pressure balance of the refrigerant changes rapidly and the four-way valve is reversed. As sound is generated, it propagates into the room and causes discomfort. Therefore, although not desirable from the viewpoint of shortening the defrosting time and heating efficiency, the compressor 1 is stopped for the time t _c set from the outside so as to minimize the influence.

Regarding the defrosting end reference temperature, FIG.
As shown in, it is set higher as the outside air temperature T _o increases. In practice, typical threshold values are set for the outside air temperature, and different defrosting termination reference temperatures are adopted with these threshold values as boundaries.

Further, in this embodiment, regarding the first defrosting during the heating operation, the defrosting condition is that the temperature of the outdoor heat exchanger 6 has dropped to the defrosting start reference temperature. Determines the defrosting start point based on the temperature of the outdoor heat exchanger 6 or the heating operation duration time from the last defrosting end time. Here, by appropriately setting the reference value for the heating operation duration time, it is possible to shorten the operation time when the heating capacity is reduced. FIG. 4 shows this relationship. That is, during the heating operation, the heating capacity is gradually reduced due to frost formation, and the heating capacity is extremely reduced when the temperature of the outdoor heat exchanger reaches the defrosting start reference temperature. When such an operation is repeated, it is inevitable that each time the operation is performed in a state in which the capacity is deteriorated as indicated by the diagonal lines.
Therefore, the first round of defrosting the defrost start point is determined on the basis of the temperature of the outdoor heat exchanger, the outdoor heat exchanger Tara preset time H _TS brat for the second and subsequent defrosting Start defrost control prior to temperature. As a result, it is possible to avoid the operation in a state where the capacity is lowered as much as possible, and it is possible to shorten the defrosting period.

FIG. 5 is a flow chart showing a processing procedure when the microcomputer is provided with each of the above defrosting control functions. The detailed control operation will be described below with reference to this flowchart.

First, in step 101, it is judged whether or not the heating operation is in progress. If the heating operation is not in progress, another control operation such as the cooling operation and the blowing operation is executed in step 102 to perform the heating operation. In that case, the processing from step 103 onward is executed. Step 103 In the outside air temperature T _o, reads the outdoor heat exchanger temperature T _e, followed by either the temperature T _e of step 104, the outdoor heat exchanger is lower than the reference temperature T _es1 = -8 ° C. start defrosting not If it is lower, move to the processing of step 106 and below, and if not, step
Execute the processing of 105. The process of step 105 determines whether or not the timer started after the defrosting operation has timed up. If defrosting has not been performed once, the time will not be up. The process moves to the heating operation process of step 121, and then returns to the process of step 101.

That is, if the temperature T _e of the outdoor heat exchanger is the reference temperature T _es1 = −8 ° C. or higher for starting defrosting, and the defrosting operation has not been performed once since the start of the heating operation, the heating operation is continued. Then, when the temperature T _e of the outdoor heat exchanger falls _below the reference temperature T _es1 = −8 ° C. for starting defrosting, step 10 is begun.
6 Move to the following process.

Next, at step 106, it is judged if the outside air temperature T _o is higher than the reference value T _os1 = 0 ° C. If it is higher than T _os1 , fan operation defrosting is performed at step 107. . That is, the four-way valve is reversed to put the compressor in the cooling mode while continuing the operation of the compressor for defrosting, but the outdoor fan is kept operating. Then, read the outside air temperature T _o, the outdoor heat exchanger temperature T _e at step 108, further, the reference value is the outside air temperature T _o at step 109 T _os2 = -
Determine if it is below 2 ° C. Here, the outside temperature T
_{If o} is lower than the reference value T _os2, it is determined in step 110 whether or not the temperature of the outdoor heat exchanger has risen to the defrosting end reference temperature T _es2 = 3 ° C., and if it has risen, step 11
5 Move on to the processing below, and if not rising, step 108
Return to processing. On the other hand, when the outside air temperature T _o is the reference value T _os2 = −2 ° C. or more in step 109, step 11
At 1, the temperature of the outdoor heat exchanger is the defrosting end reference temperature T _es3 =
It is determined whether or not the temperature has risen to 5 ° C., and if the temperature has risen, the process proceeds to step 115 and subsequent steps, and if the temperature does not rise, the process returns to step 108.

On the other hand, the fan stops defrosting is performed at step 112 if the outside air temperature T _o is determined to be lower than the reference value T _os1 = 0 ° C. at step 106. That is, the four-way valve is reversed and the cooling mode is set to defrost while the operation of the compressor is continued, but the outdoor fan is stopped at this time. Then, in step 113, the outdoor heat exchanger temperature T _e is read, and in step 114, it is determined whether or not the temperature of the outdoor heat exchanger has risen to the defrosting end reference temperature T _es4 = 7 ° C., and the temperature rises. If so, step 115 and the following steps are performed.

Next, at step 115, if the outdoor fan is stopped, it is operated, and then at step 116,
The timer A for setting the compressor stop time t _c = 0 to 200 sec for preventing the occurrence of the reversal sound of the four-way valve is started, and it is determined in step 117 whether or not the time is up. If the time is not up, that is, until the time is up, stop the compressor in step 118,
When the time is up, the compressor is operated in step 119 and the four-way valve is switched to the heating side at the same time. Further, in step 120, the heating continuation timer H ^T is started or reset and the process proceeds to step 121.

By the above processing, when the outside air temperature at the start of defrosting is 0 ° C. or less, fan defrosting is executed until the temperature returns to 7 ° C., and when the outside air temperature exceeds 0 ° C., the fan is defrosted. The operation defrosting is executed, and at the time of the fan operation defrosting, the defrosting is ended in accordance with the defrosting end reference temperature of 3 ° C. or 5 ° C., which is set to be higher as the outside air temperature is higher. Further, the stop control of the compressor is also performed to prevent the generation of the reversing sound of the four-way valve. In addition, setting the set value of the timer A to 0 is nothing but continuous operation of the compressor, and so-called capacity priority operation can be performed with priority given to preventing generation of switching noise of the four-way valve. .

Next, after the heating continuation timer H _T is started by the processing of step 120, that is, after the first defrosting is completed, step 104 or step 105 is performed.
Since the defrosting operation is started after the processing of No. 1, the second and subsequent defrosting operations are started based on the temperature of the outdoor heat exchanger or the heating operation duration time after the last defrosting operation.

FIG. 6 shows the temperature change of the outdoor heat exchanger during the defrost control according to this embodiment and the temperature change of the outdoor heat exchanger during the defrost control according to the conventional example at the same time. Assuming that defrosting is started at t ₁ , in the conventional example, defrosting is finished at time t ₁₁ , but in the present embodiment, defrosting is finished at time t ₂ .
The defrosting time can be shortened significantly.

Next, FIGS. 7 to 10 are for explaining another embodiment of the present invention. Since the hardware configuration for defrosting control is exactly the same as that of FIG. 1, its explanation is omitted. The operation of the control device will be described below.

In this embodiment, as shown in FIG. 7 (a), if the outdoor fan continues to operate until the defrosting ends, as shown in FIG. 15, air is blown to the defrosting of the central portion B near the pipe. May have a cooling effect. Therefore, as shown in FIG. 7B, fan operation defrosting is performed for a time t _s from the start of defrosting, and fan stop control is performed thereafter.

Here, in light of the phenomenon that the absolute amount of frost attached to the outdoor heat exchanger is large when the outside air temperature is higher than 0 ° C. and is small when the outside air temperature is lower than 0 ° C., the fan operates when the outside air temperature is high. the time t _s of the defrosting longer, by shortening the time t _s of the fan operation defrosting when the outside air temperature is low, so as to enhance the control effect of performing fan stop defrosting after the fan operation defrosting ing.

On the other hand, even if the fan operation defrosting is switched to the fan stop defrosting, when the outside air temperature is high, the effect of the air blow before the switching is great, so that the defrosting is finished even if the temperature of the pipe is low. However, focusing on the phenomenon that defrosting does not end unless the temperature of the pipe becomes high to some extent when the outside air temperature is low, in this embodiment, as shown in FIG. The frost end reference temperature is low.

FIG. 9 is a chart showing the relationship between the outside air temperature, the fan operation defrosting time, and the defrosting end reference temperature.

FIG. 10 is a flow chart showing the processing procedure of the microcomputer for performing the above-mentioned defrost control.
The detailed control operation will be described below with reference to this flowchart.

First, in step 201, it is judged whether or not the heating operation is in progress. If the heating operation is not in progress, then in step 202 another control operation, for example, a cooling operation, a blow operation, etc., is executed to perform the heating operation. If so, the processing from step 303 onward is executed. Step 203 In the outside air temperature T _o, reads the outdoor heat exchanger temperature T _e, followed by determining whether or not the temperature T _e of the outdoor heat exchanger is lower than the reference temperature T _es1 = -8 ° C. start defrosting If it has fallen, the process proceeds to step 206 and subsequent steps, and if it has not fallen, the process of step 205 is executed. The process of step 205 is to determine whether or not the timer started after the defrosting operation has timed up. If defrosting has not been performed once, the time will not be up. The process moves to the heating operation process of step 233, and then returns to the process of step 201.

Next, the timer is started B to limit the defrosting time in step 206, followed by range outside air temperature T _o is predetermined in step 207, i.e., T _o ≧ 0 ° C.,
It is determined which of 0 ° C.> T _o ≧ −5 ° C. and −5 ° C.> T _o .

If the outside temperature T _o is higher than 0 ° C. according to this judgment, the fan operating time t is determined in step 208.
_The timer C in which _s is set to 40 sec and 20 sec is started, and in the next step 209, the four-way valve is reversed to perform the fan operation defrosting. Then, in step 210, 40 seconds
After waiting for the time, the outdoor fan is stopped in step 211 to move to fan defrosting, and then the temperature T _e of the outdoor heat exchanger is read in step 212, and the temperature is raised to 4 ° C or more in step 213. If it is 4 ° C or higher, the processing from step 226 is executed. Even if it is lower than 4 ° C, it is determined in step 214 that the set time B _s of the defrosting time limit timer B has elapsed. Then, the processing from step 226 is executed.

Further, in some cases in the range outside air temperature T _o is 0 ℃> T _o ≧ -5 ℃ by the process of step 207, the timer is started C set the fan operation operation time t _s at step 215 In the next step 216, the four-way valve is reversed to perform the fan operation defrosting. And step 217
After waiting for 20 seconds at step 218, the outdoor fan is stopped at step 218 to move to fan defrosting. Then, at step 219, the temperature T _e of the outdoor heat exchanger is read.
At 220, determine whether the temperature has risen above 6 ° C, and
If the temperature is above ℃, execute the processing from step 226 to 6 ℃
Even if it is lower than the setting time B of the defrosting time limit timer B
_It is determined in step 221 that _s has elapsed and step 22
Execute the processing from 6 onwards.

[0046] On the other hand, when the outside air temperature T _o is determined to be lower than -5 ° C. by the process of step 207, with reversing the four-way valve at step 222, the fan stops defrosting stops the outdoor fan And then step 22
In step 3, the temperature T _e of the outdoor heat exchanger is read, and in step 224, it is determined whether or not the temperature has risen to 8 ° C or higher. Even when it is low, it is determined in step 221 that the set time B _s of the defrosting time limit timer B has elapsed, and the processing from step 226 is executed.

Next, in step 226, the timers B and C are reset, the outdoor fan is operated in step 227, and then, in step 228, the compressor for stopping the reversing sound of the four-way valve is stopped. Time t _c = 0 to 200 sec
The timer A for setting is started, and it is determined in step 229 whether the time is up. When the time is not up, that is, until the time is up, the compressor is stopped in step 230, and when the time is up, the compressor is operated in step 231 and the four-way valve is switched to the heating side. Further, in step 232, the heating continuation timer H ^T is started or reset, and then step 23
Move on to step 3.

By the above processing, when the outside air temperature at the start of defrosting is -5 ° C or lower, fan defrosting is executed until the temperature returns to 8 ° C, and the outside air temperature exceeds -5 ° C. When the fan operation defrosting is performed for a set time, the operation shifts to the fan stop defrosting, and at least during the fan stop defrosting, according to the defrosting end reference temperature set to become lower as the outside air temperature is higher. The control for ending the defrosting is performed.

Next, FIG. 11 is a schematic constitutional view of another embodiment, in which the same elements as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. This is the output side of the compressor 1,
A refrigerant bypass path is provided between the refrigerant and the inlet side of the outdoor heat exchanger 6 when viewed in the refrigerant circulation direction during heating operation, and a two-way valve 8 is provided in the bypass path. The difference from FIG. 1 is that the opening / closing control is performed by.

In this embodiment, the same control as the defrosting control shown in the flowchart of FIG. 5 or FIG. 10 is performed by opening the two-way valve instead of switching the four-way valve. As shown in FIG. 12, the frost is generated at the defrosting start time t _{1 while} keeping the four-way valve in the heating mode.
To open the two-way valve 8 at the, at the defrost end time t ₂ two-way valve 8
To close.

As concrete processing, FIG. 5 or FIG.
The two-way valve is turned on (open) instead of the four-way valve being turned off in the flowchart, and the two-way valve is turned off instead of the four-way valve being turned on.
You can set it to (closed). Further, in this case, stop control of the compressor at the end of defrosting is unnecessary.

Thus, according to the embodiment shown in FIG. 11, the same control as the above-mentioned defrost control can be performed.

[0053]

As is apparent from the above description, according to the air conditioner of the first aspect, the fan operation defrosting is executed when the outside air temperature exceeds the predetermined value, and at that time, the outside air temperature is defrosted. Since the defrosting is terminated in accordance with the defrosting termination reference temperature that is set to be higher as the temperature is higher, it is possible to shorten the interruption time of the heating operation and thereby suppress the decrease in room temperature to a small level.

Further, according to the air conditioner of the second aspect, when the outside air temperature exceeds the predetermined value, the fan operation defrosting is performed for a set time and then the fan stop defrosting is performed. When defrosting the fan, defrosting is terminated according to the defrosting termination reference temperature that is set so that it becomes lower when the outside air temperature is higher, so the cooling phenomenon of the outdoor heat exchanger by the outdoor fan was fully added. Defrosting can be realized, and the heating operation interruption time can be further shortened.

Further, in the air conditioner according to the third aspect of the present invention, the time for performing fan operation defrosting is set to be longer as the outside air temperature is higher. The amount is controlled to be constant, and stable defrost control can be performed.

Furthermore, the first defrosting start point is determined based on the temperature of the outdoor heat exchanger, and the second and subsequent defrosting start points are the temperature of the outdoor heat exchanger or after the last defrosting. Since the determination is made based on the heating operation duration time, it is possible to further shorten the heating operation interruption time together with the heating efficiency.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a first embodiment of the present invention.

FIG. 2 is a time chart for explaining the operation of the first embodiment of the present invention.

FIG. 3 illustrates the operation of the first embodiment of the present invention.
The line diagram showing the relation between defrosting termination standard temperature and outdoor temperature.

FIG. 4 illustrates the operation of the first embodiment of the present invention.
A diagram showing the relationship between heating capacity and elapsed time.

FIG. 5 is a flowchart for explaining the operation of the first embodiment of the present invention.

FIG. 6 is a graph for explaining the effect of the first embodiment of the present invention.
The diagram which showed the relationship between the outdoor heat exchanger temperature and time.

FIG. 7 is a time chart for explaining the operation of the second embodiment of the present invention.

FIG. 8 illustrates an operation of the second embodiment of the present invention.
The line diagram showing the relation between defrosting termination standard temperature and outdoor temperature.

FIG. 9 is a flow chart for explaining the operation of the second embodiment of the present invention.
The figure which showed the relationship between the outdoor temperature, the operating time of an outdoor fan, and a defrosting termination reference temperature door.

FIG. 10 is a flowchart for explaining the operation of the second embodiment of the present invention.

FIG. 11 is a schematic configuration diagram of a third embodiment of the present invention.

FIG. 12 is a time chart for explaining the operation of the third embodiment of the present invention.

FIG. 13 is a time chart for explaining the operation of the conventional air conditioner.

FIG. 14 is a diagram showing the relationship between the outdoor heat exchanger temperature and time in order to explain the operation of the conventional air conditioner.

FIG. 15 is a perspective view showing a configuration of an outdoor heat exchanger and a side view showing a frosted state thereof for explaining the principle of the present invention.

[Explanation of symbols]

 1 Compressor 2 Four-way valve 3 Indoor heat exchanger 4 Indoor fan 5 Throttle device 6 Outdoor heat exchanger 7 Outdoor fan 8 Two-way valve 8 11, 12 Temperature sensor

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Abiko Seiichi 336 Tatehara, Fuji City, Shizuoka Prefecture Toshiba Abu E Co., Ltd. Fuji Office

Claims (6)

[Claims] 1. An indoor unit has an indoor heat exchanger, and an outdoor unit has an outdoor fan, a compressor, a four-way valve and an outdoor heat exchanger, of which an indoor heat exchanger, a compressor, a four-way valve and In an air conditioner in which outdoor heat exchangers are connected by pipes to form a refrigeration cycle, first temperature detecting means for detecting a temperature of the outdoor heat exchanger, and second temperature detecting means for detecting an outdoor air temperature. During the heating mode operation of the refrigeration cycle, a function of fan defrosting for defrosting the outdoor heat exchanger by stopping the outdoor fan, and the outdoor heat exchanger while operating the outdoor fan With a function of defrosting fan operation defrosting, when the outside air temperature at the start of defrosting is below a predetermined value, the fan stop defrosting is executed, and when the outside air temperature exceeds a predetermined value, Perform fan operation defrosting and In operation defrosting, the air conditioner being characterized in that and a control device to end the defrosting according to the set defrost termination criterion temperature so high as when the outside air temperature is high. 2. The indoor unit has an indoor heat exchanger, and the outdoor unit has an outdoor fan, a compressor, a four-way valve and an outdoor heat exchanger, of which the indoor heat exchanger, the compressor, the four-way valve and In an air conditioner in which outdoor heat exchangers are connected by pipes to form a refrigeration cycle, first temperature detecting means for detecting a temperature of the outdoor heat exchanger, and second temperature detecting means for detecting an outdoor air temperature. During the heating mode operation of the refrigeration cycle, a function of fan defrosting for defrosting the outdoor heat exchanger by stopping the outdoor fan, and the outdoor heat exchanger while operating the outdoor fan With a function of fan operation defrosting to defrost, the fan stop defrosting is executed when the outside air temperature at the start of defrosting is below a predetermined value, and set when the outside air temperature exceeds a predetermined value. Defrosting the fan for the specified time After the execution, the control device shifts to the fan stop defrosting, and at the time of the fan stop defrosting, the control device ends the defrosting according to the defrosting end reference temperature set to become lower as the outside air temperature becomes higher. An air conditioner characterized by the above. 3. The air conditioner according to claim 2, wherein the fan operation defrosting time is set to be longer as the outside air temperature is higher. 4. The first defrost start point is determined based on the temperature of the outdoor heat exchanger, and the second and subsequent defrost start points are the temperature of the outdoor heat exchanger or after the previous defrost end. The air conditioner according to any one of claims 1 to 3, characterized in that the determination is made based on the heating operation duration time. 5. The air conditioner according to claim 1, wherein in the defrosting operation, the four-way valve is reversed to operate the refrigeration cycle in a cooling mode. 6. A refrigerant bypass circuit, which can be controlled to open and close, is provided between the discharge side of the compressor and the inlet side of the outdoor heat exchanger, and the defrosting is performed by opening the bypass circuit. The air conditioner according to any one of claims 1 to 4, wherein