JP3329603B2 - Air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump type air conditioner having a variable speed outdoor blower, and more particularly to controlling the number of rotations of an outdoor blower per predetermined time to an appropriate number of rotations according to an outdoor load. Related to air conditioners.

[0002]

2. Description of the Related Art Conventionally, in an air conditioner of this type, in order to control a high pressure side of a refrigeration cycle from rising to a predetermined pressure or more due to an overload or the like during a heating operation, heat of a gaseous refrigerant having a high temperature and a high pressure is controlled. When the temperature of the indoor heat exchanger performing the condensing action rises above a predetermined value, the number of rotations (rotation speed) of the outdoor blower per predetermined time is reduced, so that the outdoor heat exchanger performs the vaporization and vaporization of the liquid refrigerant. The amount of heat absorbed by the exchanger is reduced to prevent the high pressure side from rising above a predetermined pressure.
This is called release control.

[0003] The release control is released when the temperature of the indoor heat exchanger falls below a predetermined value.

[0004]

However, in such a conventional release control method, when the load on the outdoor heat exchanger during the heating operation is low, that is, when the outside air temperature is relatively high, the release control during the release control is performed. If the minimum rotation speed of the outdoor blower is too low, the liquid refrigerant vaporizes in the outdoor heat exchanger and the liquid refrigerant returns to the compressor, which tends to cause liquid back, which lowers the reliability and durability of the refrigeration cycle. There is a problem to do.

On the contrary, when the load on the outdoor heat exchanger is high and the minimum rotation speed of the outdoor blower is too high, the amount of heat absorbed by the outdoor heat exchanger increases, and consequently the indoor heat exchanger has Since the heat dissipation increases, the high pressure side of the refrigeration cycle rises, the high pressure switch operates, and the compressor is easily stopped. For this reason, since the ON / OFF of the high pressure switch is repeated in a short time and the intermittent operation is repeated in a short time, there is a problem that the reliability and durability of the refrigeration cycle are reduced.

Conventionally, when the rotation speed of the outdoor blower is reduced by the release control and then the release control is released, the rotation speed of the outdoor blower is reduced as shown by a curve A in FIG. A certain amount α than the rotation speed T1
It is raised at a stretch to a low rotation speed T2, and then,
After a predetermined time ta, the rotation speed is increased by a predetermined amount α and returned to the rotation speed T1 before the start of the release control.

That is, since the rotation speed of the outdoor blower is increased at a stretch to T2 after the release control is released, the pressure fluctuation of the refrigeration cycle is large and the stability of the refrigeration cycle is low.

When the conventional heating operation is started, the outdoor blower is operated at the maximum rotation speed (highest speed) for a predetermined time in order to prevent an abnormal rise in high pressure. I'm driving.

For this reason, when the cooling operation is performed at a low outside air temperature or when the refrigerant in the indoor heat exchanger is laid down, the low pressure is hardly increased even if it is started several times. When the blower is started at the maximum rotation speed, the flow rate of the liquid refrigerant liquefied in the outdoor heat exchanger increases, but the flow rate of the refrigerant radiated and condensed in the indoor heat exchanger is small. In addition, the low pressure switch may operate due to abnormal lowering of the low pressure side, and the compressor may be stopped abnormally.

Therefore, the present invention has been made in view of such circumstances, and an object of the present invention is to increase the pressure on the high pressure side of the refrigeration cycle to a predetermined pressure or more, or to decrease the pressure on the low pressure side to a predetermined pressure or less. An air conditioner that can achieve both reliability and durability by controlling the number of rotations of the outdoor blower per predetermined time to an appropriate number of rotations according to the outdoor load while suppressing or effectively preventing the air blower from performing. Is to provide.

[0011]

The present invention is configured as follows to solve the above-mentioned problems.

[0012] The invention described in claim 1 of the present application (hereinafter referred to as the first invention)
The invention discloses a refrigeration cycle in which a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, an indoor heat exchanger, etc. are connected, an outdoor blower capable of variable speed, and a rotational speed of the outdoor blower from the highest speed. An outdoor blower speed control means for controlling to a minimum speed and having this minimum speed value in multiple stages from high to low; an indoor heat exchange temperature sensor for detecting the temperature of the indoor heat exchanger; An indoor controller that sends a release signal to the outdoor blower speed control means when the detection value of the intersection temperature sensor reaches a predetermined temperature or higher; and, when a release signal is received from the indoor controller during heating, the outdoor controller Means for selecting and determining the speed of the blower from among preset minimum speeds.

According to a second aspect of the present invention (hereinafter referred to as a second aspect), the air conditioner of the first aspect operates the compressor when a predetermined high pressure of the refrigeration cycle is detected. A high-pressure switch for stopping the operation, and when the high-pressure switch is operated, means for operating the minimum speed value of the outdoor blower at the time of heating at a rotation speed set value lower than the minimum speed set value before the operation is provided. It is characterized by.

Further, the invention according to claim 3 of the present application (hereinafter referred to as a third invention) is the air conditioner according to claim 1, further comprising a temperature sensor in the outdoor heat exchanger,
The minimum speed value of the outdoor blower is determined based on the detection value of the outdoor heat temperature sensor before starting the compressor, and when the outdoor heat exchange temperature sensor is equal to or higher than a predetermined value, the minimum speed of the outdoor blower is set to the lower side. Means for setting the set value to a higher set value when the set value is lower than a predetermined value.

According to a fourth aspect of the present invention (hereinafter, referred to as a fourth aspect), in the air conditioner according to the first aspect, the detection value of the indoor heat exchange temperature sensor is a predetermined value for releasing the release. When the temperature falls below the temperature, the indoor controller sends a release release signal to the outdoor blower speed control means, and the release release signal causes the outdoor fan to gradually increase the rotation speed from the lowest speed operation to the normal operation speed. And means for causing it to be provided.

The invention described in claim 5 of the present application (hereinafter referred to as a fifth invention) relates to a refrigeration cycle in which a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, an indoor heat exchanger, etc. are connected. A variable-speed outdoor blower, an outdoor blower speed control means for controlling the speed of the outdoor blower, and a low-pressure switch for detecting a low-pressure pressure of the refrigeration cycle.When the low-pressure switch is operated, the compressor is activated. When the air blower is stopped and restarted after a predetermined time, a means for controlling the speed of the outdoor blower to a rotation value lower than the rotation speed at the previous start is provided.

Further, the invention described in claim 6 of the present application (hereinafter referred to as a sixth invention) relates to a refrigeration cycle in which a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, an indoor heat exchanger and the like are connected. An outdoor blower having a variable speed, and a cooling liquid side of the refrigeration cycle communicating with a suction side of the compressor, and a bypass circuit provided with a decompression device on the way, and detecting a refrigerant temperature in the bypass circuit. When the saturation temperature sensor detects a value equal to or less than a predetermined value, the compressor is stopped, and when the compressor is restarted after a predetermined time, the speed of the outdoor blower is set to be lower than the rotation speed at the previous start. It is characterized by comprising means for controlling the rotation speed to a low value.

[0018]

[Action]

<First invention> During the heating operation, when the control means receives a release signal from the indoor controller, the control means controls the rotation speed of the outdoor blower to a preset minimum speed value. As a result, the amount of refrigerant liquefied in the outdoor heat exchanger decreases, and when the outdoor load is low, the amount of refrigerant radiated in the indoor heat exchanger is also small. The signal is released and the outdoor blower is operated again at the maximum speed.

Therefore, the outdoor blower can be operated at an appropriate rotation speed according to the outdoor load, so that a pressure increase on the high pressure side of the refrigeration cycle can be suppressed, and the reliability and durability of the refrigeration cycle can be improved. We can work together.

<Second Invention> In the heating operation, even if the control means receives the release signal and controls the outdoor blower to the minimum rotational speed, the high pressure continues to rise when the outdoor load is high. The compressor operates to temporarily stop the operation of the compressor to stop the pressure increase on the high pressure side. At the same time, the pressure of the refrigeration cycle is further reduced by operating the outdoor blower at a rotation speed lower than the minimum speed value before the operation of the high pressure switch, so that the high pressure switch returns and the compressor starts again. The high pressure does not reach the predetermined high pressure immediately. For this reason, short intermittent operation of the compressor can be effectively prevented, and both the reliability and the durability of the refrigeration cycle can be improved.

<Third invention> Since the outside air temperature is detected by the outdoor heat exchanger temperature sensor before the compressor is started, and the minimum speed value of the outdoor blower is selected based on the detected outside air temperature, the outdoor air blower of this outdoor blower is selected. The rotation speed can be controlled to an appropriate speed according to the outdoor load. For this reason, the pressure increase on the high pressure side of the refrigeration cycle can be suppressed, so that both the reliability and durability of the refrigeration cycle can be improved.

<Fourth invention> After the release control is released, the rotation speed of the outdoor blower is gradually increased from the minimum to the normal speed without being increased at once, so that the cycle fluctuation (hunting) can be suppressed and stabilized. it can.

<Fifth Invention> When the low pressure side pressure drops for some reason at the time of starting the cooling operation, the low pressure switch operates to stop the compressor, so that failure of the cycle equipment can be prevented beforehand. Also, when restarting this compressor, the rotation speed of the outdoor blower is controlled to a lower rotation speed than the rotation speed at the previous start, so the amount of refrigerant that condenses and liquefies in the outdoor heat exchanger is reduced. As a result, the high-pressure side pressure can be raised and the low-pressure side pressure can be raised, so that the compressor can be started.

<Sixth Invention> Since the pressure on the low pressure side is detected by detecting the temperature of the liquid refrigerant by the saturation temperature sensor, the low pressure switch can be omitted.

The low-voltage switch is not only simple in structure, but also expensive because it requires high accuracy. However, since the saturated temperature sensor is an inexpensive temperature sensor, the cost can be reduced.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 9, the same or corresponding parts are denoted by the same reference numerals.

FIG. 1 is a refrigeration cycle diagram of an embodiment of an air conditioner according to the present invention. In this figure, an air conditioner 1 has a compressor 3 whose rotation speed is controlled by an inverter 2.
A refrigeration cycle is constructed by connecting an outdoor heat exchanger 6 having an outdoor blower 5 having a four-way valve 4 and a variable rotation speed 5, an expansion valve 7, and an indoor heat exchanger 9 having an indoor blower 8 in order through a refrigerant pipe 10. I have.

In this refrigeration cycle, when the refrigerant is circulated in the direction of the dashed arrow in the drawing by switching operation of the four-way valve 4, heating operation is performed, and when the refrigerant is circulated in the direction of the solid line arrow in the drawing, cooling operation is performed.

In the refrigeration cycle, a high pressure switch 11 is provided on the refrigerant discharge side, which is a high pressure side of the compressor 3, while an outdoor heat exchange sensor 12 for detecting the temperature of the outdoor heat exchanger 6 and An indoor heat exchange sensor 13 for detecting temperature is provided, and the indoor heat exchange sensor 13 and the indoor blower 8 are electrically connected to an indoor controller 14 composed of, for example, a microprocessor or the like via a signal line.

The indoor controller 14 is further electrically connected to an outdoor controller 15 comprising a microprocessor or the like, and reads the indoor heat exchanger 9 read from the indoor heat exchange sensor 13.
As shown in FIG. 2, the release signal is transmitted to the outdoor controller 15 when the temperature detection value rises above the release temperature of 60 ° C., for example, and when the temperature detection value falls below the release release temperature of 58 ° C. This is to stop signal output.

The room controller 14 reads a room temperature detection value from a room temperature sensor (not shown), compares the room temperature detection value with a room temperature set value set by a remote controller (not shown), and sets an operation command frequency for reducing the deviation to zero. A signal is also provided to the inverter 2 via the outdoor controller 15 to control the number of rotations of the compressor 3 per predetermined time, that is, the rotation speed, so that the room temperature detection value is controlled to a set value.

On the other hand, the outdoor controller 15 is connected to the inverter 2,
The four-way valve 4, the outdoor blower 5, the high-pressure switch 11, and the outdoor heat exchange sensor 12 are electrically connected to each other via signal lines, and are appropriately controlled. For example, the outdoor controller 15 divides the rotation speed of the outdoor blower 5 stepwise from the first rotation speed of the lowest rotation speed to the 16th rotation speed of the maximum rotation speed during the heating operation, and reduces the minimum rotation speed value from the eighth rotation speed to the first rotation speed. , The initial value of the minimum rotation speed value is set to the eighth speed, and the control is performed according to the procedure of the processing program shown in the flowchart of FIG.

Next, an example of a method of controlling the rotation speed of the outdoor blower 5 will be described with reference to the flowchart of FIG. 3, where S1 to S10 indicate each step of the flowchart.

First, in S1, the outdoor controller 15 sets the four-way valve 4
It is determined from the switching angle whether or not the refrigeration cycle is currently in the heating operation. If YES, it is determined in S2 whether the high pressure switch 11 is operating, that is, the high pressure on the refrigerant discharge side of the compressor 3 is equal to or higher than a predetermined pressure. Is determined, the process proceeds to S3 if YES and to S4 if NO.

That is, if the outdoor load is high and the minimum speed value of the outdoor blower 5 is too high, the high pressure on the discharge side of the compressor 3 rises, so that the high pressure switch 11 operates. The operation of the compressor 3 is stopped to prevent damage to the cycle components due to overpressure, and the minimum rotation speed value of the outdoor blower 5 is reduced by one speed from the rotation speed of the previous operation.

Therefore, if the rotation speed of the outdoor blower 5 during the previous operation is, for example, the eighth speed, the reception of the current release signal reduces the rotation speed to the seventh speed, which is one speed lower than the eighth speed. The speed is reduced by one speed according to the length of the signal reception time.

In S3, even after the high pressure switch 11 is operated and the operation of the compressor 3 is stopped, the minimum rotation speed value of the outdoor blower 5 is further reduced step by step by one step. Can be lowered sufficiently.

For this reason, short intermittent operation in which the high-pressure switch 11 is operated and the operation of the compressor 3 is stopped within a short time after the restart of the compressor 3 can be effectively prevented.

On the other hand, when the high pressure switch 11 is not operating due to a low outdoor load or the like in S2, it is determined in S4 whether or not a release signal is received from the indoor controller 14.
If YES, the process proceeds to S5, and if NO, the process proceeds to S6.

In S5, it is further determined whether or not release control is currently being performed. If YES, that is, if release control is being performed, the process returns to S1 again, and the above steps are repeated.

However, when the release control is not currently being performed in S5, since the release signal received in S4 is the first time, the rotation speed of the outdoor blower 5 is controlled to the minimum speed value in S7. As a result, the amount of refrigerant vaporized in the outdoor heat exchanger 6 is reduced, so that the suction side and the discharge side of the compressor 3 to which the refrigerant returns can be reduced.
Return to 1 and repeat the following steps.

On the other hand, when the release control is being performed in S6, since the release signal has not been received in S4 in the preceding stage, it is determined that the release signal has been released, and the rotational speed of the outdoor blower 5 is increased to the maximum in S8. The speed is returned to the normal heating operation, the process returns to S1, and the above steps are repeated.

However, if the release control is not being performed in S6, it is determined in S9 whether the release signal has not been continuously received for a predetermined time of, for example, 10 minutes. If NO, the process returns to S1, and if YES, Raises the minimum speed value of the outdoor blower 5 by one speed. However, control is performed so as not to exceed the upper limit of the minimum speed value, for example, the eighth speed, the process returns to S1, and the above steps are repeated. Therefore, if the state without the release signal continues, the minimum speed value of the outdoor blower 5 becomes 10
Since the speed is gradually increased in steps of one speed every minute and is not returned at a stretch as in the conventional example, hunting of the refrigeration cycle can be prevented and stabilized.

Therefore, according to this embodiment, when the outdoor controller 15 receives the release signal, the outdoor blower 5
As the rotation speed is reduced to the minimum speed value, and during the reception of the release signal, the minimum speed value of the outdoor blower 5 is gradually reduced gradually with the lapse of time.
The rotation speed of the outdoor blower 5 can be controlled to an appropriate rotation speed according to the outdoor load.

Therefore, when the outdoor load is low, the minimum speed value of the outdoor blower 5 is reduced too much at a stretch, so that it is possible to effectively prevent the liquid back from being generated in the compressor 3.

When the outdoor load is high, the outdoor blower 5
Since the minimum speed of the refrigeration cycle is too high, it is possible to effectively prevent the high-voltage switch 11 from being turned on and off in a short time, so that both the reliability and the durability of the refrigeration cycle can be improved.

FIG. 4 is a flow chart showing another example of a method for controlling the rotation speed of the outdoor blower 5, wherein the temperature of the outdoor heat exchanger 6 before heating the compressor 3 during heating operation is, for example, 10 When the temperature is equal to or higher than the predetermined value of ° C., the minimum speed of the outdoor blower 5 is reduced by one speed at a time, and when the temperature is lower than the predetermined value of 10 ° C., the minimum speed value of the outdoor There is a feature in controlling.

That is, the outdoor heat exchanger 6 before starting the compressor 3
Is detected by the outdoor heat exchange sensor 12 to detect the outdoor air temperature and the outdoor load, and the minimum speed value of the outdoor blower 5 is selected based on the outdoor load. The rotation speed can be controlled to an appropriate value according to the outdoor load. Therefore, both the reliability and the durability of the refrigeration cycle can be improved as in the above embodiment.

FIG. 5 shows that when the release control is released during the heating operation, the minimum rotation speed L of the outdoor blower 6 is not increased at once to the rotation speed H during the normal operation, but the predetermined speed β is increased stepwise at predetermined time intervals t. The feature is that it is gradually raised.

According to this, the minimum rotation speed L of the outdoor blower 5 is gradually increased to the rotation speed H in the normal operation, so that the fluctuation of the cycle pressure can be suppressed to a small extent. For this reason, hunting of the cycle pressure can be effectively prevented, and the refrigeration cycle can be stabilized.

FIG. 6 is a refrigeration cycle diagram of still another embodiment of the present invention. In this embodiment, a low pressure switch 16 provided on a refrigerant suction side, which is a low pressure side of the compressor 3, detects a pressure lower than a predetermined pressure. After the operation of the compressor 3 is stopped at this time, the outdoor blower 5 is characterized in that the rotation speed is reduced by the outdoor controller 15a from the rotation speed at the time of the previous start by the outdoor controller 15a. Therefore, the same or corresponding parts are denoted by the same reference numerals or are not shown in the drawings, and redundant description is omitted.

That is, in this embodiment, when the cooling operation is started when the outside air temperature is relatively low, it is difficult to start the cooling operation because the pressure on the low pressure side of the refrigeration cycle does not immediately increase. The method is characterized in that the rotation speed of the outdoor blower 5 is controlled in order to facilitate the operation.

For example, in the case of a low load condition in which the cooling operation is performed when the outside air temperature is relatively low, or in a case where the cooling operation is to be started when the refrigerant in the indoor heat exchanger 9 is laid down, FIG. Even if the compressor 3 is started once or twice as shown in FIG. 7, the low-pressure switch is activated and the compressor 3 cannot be easily started because the low-pressure side pressure is lower than the operating point of the low-pressure switch 16. .

In such a case, as shown in FIGS. 7 and 8, the outdoor controller 15 controls the rotation speed of the outdoor blower 5 per predetermined time, that is, the rotation speed, for each operation of the low-pressure switch 16, as shown in FIGS. The compressor 3 is started by gradually increasing the high-pressure side and gradually increasing the low-pressure side by gradually decreasing stepwise by γ. However, the low pressure switch 16
When the number of times of operation has reached a predetermined number or more, the operation is stopped as a low pressure abnormality.

Therefore, according to the present embodiment, even when the low pressure switch 16 is operated without the pressure on the low pressure side being easily increased due to a low load or refrigerant stagnation when the cooling operation is started, the high pressure side is increased. Thus, the cooling operation can be started by increasing the pressure on the low pressure side.

When the low-pressure switch 16 has been operated a predetermined number of times or more due to some abnormal low pressure, the compressor is stopped from starting, so that failure of the refrigeration cycle equipment can be prevented.

FIG. 9 shows a refrigeration cycle according to still another embodiment of the present invention. In this embodiment, the low-pressure switch 16 shown in FIG. A bypass passage 17 is provided to connect the refrigerant outlet side of the compressor 6 to the refrigerant suction side of the compressor 3, and a capillary tube 18 as a refrigerant decompressor and a saturation temperature sensor 19 are interposed in the bypass passage 17. There is a feature.

In general, the low pressure switch 16 is required to have high accuracy for detecting a low pressure, and is expensive like general pressure switches. However, the saturation temperature sensor 19 can detect the temperature of the liquid refrigerant as the pressure on the low pressure side. This is a temperature sensor that can be manufactured. Generally, the temperature sensor has a simple structure as compared with a general pressure switch, and thus is inexpensive. Therefore, cost can be reduced.

[0059]

As described above, the first invention of the present application is:
During the heating operation, when the control means receives a release signal, the control means controls the rotational speed of the outdoor blower to a preset minimum speed value. As a result, the amount of refrigerant liquefied in the heat exchanger decreases, and when the outdoor load is low, the amount of refrigerant radiated in the indoor heat exchanger is also small, so that the cycle pressure is stable or the release signal is low. Is released, and the outdoor blower is again operated at the maximum speed.

Therefore, since the outdoor blower can be operated at an appropriate rotation speed according to the load, a pressure increase on the high pressure side of the refrigeration cycle can be suppressed, and both the reliability and the durability of the refrigeration cycle can be improved. Can be planned.

Further, according to the second invention of the present application, even when the control means receives the release signal during the heating operation and controls the outdoor blower to the minimum rotation speed, the high pressure continues to rise when the outdoor load is high. The high pressure switch is operated to temporarily stop the operation of the compressor and stop the pressure increase on the high pressure side. At the same time, the pressure of the refrigeration cycle is further reduced by operating the outdoor blower at a rotation speed lower than the minimum speed value before the operation of the high pressure switch, so that the high pressure switch returns and the compressor starts again. The high pressure does not reach the predetermined high pressure immediately. For this reason, short intermittent operation of the compressor can be effectively prevented, and both the reliability and the durability of the refrigeration cycle can be improved.

Further, in the third invention of the present application, the outdoor air temperature is detected by the outdoor heat exchanger temperature sensor before the compressor is started, and the minimum speed value of the outdoor blower is selected based on the detected outdoor air temperature. The rotation speed of the outdoor blower can be controlled to an appropriate speed according to the outdoor load. For this reason, the pressure increase on the high pressure side of the refrigeration cycle can be suppressed, so that both the reliability and durability of the refrigeration cycle can be improved.

Further, in the fourth invention of the present application, after the release control is released, the rotation speed of the outdoor blower is gradually increased from the minimum to the normal speed without increasing at a stretch, so that cycle fluctuation (hunting) is suppressed. Can be stabilized.

Further, in the fifth invention of the present application, when the low pressure side pressure drops for some reason at the time of starting the cooling operation, the low pressure switch operates to stop the compressor, thereby preventing the failure of the cycle equipment beforehand. Can be. Also, when restarting this compressor, the rotation speed of the outdoor blower is controlled to a lower rotation speed than the rotation speed at the previous start, so the amount of refrigerant that condenses and liquefies in the outdoor heat exchanger is reduced. As a result, the high-pressure side pressure can be raised and the low-pressure side pressure can be raised, so that the compressor can be started.

Further, in the sixth aspect of the present invention, since the pressure on the low pressure side is detected by detecting the temperature of the liquid refrigerant by the saturation temperature sensor, the low pressure switch can be omitted.

A pressure switch such as a low-pressure switch is not simple in structure, and is expensive because high accuracy is required. However, a saturation temperature sensor is an inexpensive temperature sensor.
Cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a refrigeration cycle diagram of an embodiment of an air conditioner according to the present invention.

FIG. 2 is a graph showing threshold values of a release signal and a release release signal output from the indoor controller shown in FIG. 1;

FIG. 3 is a flowchart illustrating an example of a method of controlling the outdoor fan rotation speed of the outdoor controller illustrated in FIG. 1;

FIG. 4 is a flowchart showing another example of the method of controlling the outdoor fan rotation speed of the outdoor controller shown in FIG. 1;

FIG. 5 is a timing chart showing an example of a method of controlling the rotation speed of the outdoor blower when release control is released by the outdoor controller shown in FIG. 1;

FIG. 6 is a refrigeration cycle diagram of another embodiment of the present invention.

FIG. 7 is a timing chart showing an example of a method of starting the cooling operation of the air conditioner shown in FIG. 6 at a low load.

FIG. 8 is a flowchart showing an example of a method for starting the cooling operation of the air conditioner shown in FIG. 6 at a low load.

FIG. 9 is a refrigeration cycle diagram of still another embodiment of the present invention.

FIG. 10 is a graph showing an example of a method of controlling the rotation speed of an outdoor blower when release control is released in a conventional air conditioner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Air conditioner 2 Inverter 3 Compressor 4 Four-way valve 5 Outdoor blower 6 Outdoor heat exchanger 7 Expansion valve 8 Indoor blower 9 Indoor heat exchanger 10 Refrigerant piping 11 High pressure switch 12 Outdoor heat exchange sensor 13 Indoor heat exchange sensor 13 Indoor control Unit 15, 15a Outdoor controller 16 Low pressure switch 17 Bypass path 18 Capillary tube 19 Saturation temperature sensor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-74536 (JP, A) JP-A-2-27941 (JP, A) JP-A-60-240941 (JP, A) 84438 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F25B 13/00 F24F 11/02 102

Claims (6)

(57) [Claims] 1. A refrigeration cycle in which a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, an indoor heat exchanger, and the like are connected, an outdoor blower having a variable speed, and a rotational speed of the outdoor blower which is from the highest speed to the lowest. An outdoor blower speed control means for controlling the maximum speed and having the minimum speed value in multiple stages from high to low, an indoor heat exchange temperature sensor for detecting the temperature of the indoor heat exchanger, and indoor heat exchange during heating operation. An indoor controller that sends a release signal to the outdoor blower speed control means when the temperature sensor detects a temperature equal to or higher than a predetermined temperature; and an outdoor blower that receives a release signal from the indoor controller during heating. Means for selecting and determining the speed from among preset minimum speeds. 2. The air conditioner according to claim 1, further comprising a high-pressure switch for stopping the operation of the compressor when a predetermined high pressure of the refrigeration cycle is detected, and when the high-pressure switch is operated, the outdoor air conditioner is heated. An air conditioner comprising means for operating a minimum speed value of a blower at a rotation speed set value lower than a minimum speed set value before the operation. 3. The air conditioner according to claim 1, further comprising a temperature sensor in the outdoor heat exchanger, wherein a minimum speed value of the outdoor blower is set to a detection value of the outdoor heat temperature sensor before starting the compressor during heating. The outdoor heat exchange temperature sensor is determined based on
An air conditioner comprising means for setting the minimum speed of the outdoor blower to a lower set value when the value is equal to or higher than a predetermined value, and setting the minimum speed to a higher value when the value is lower than the predetermined value. 4. The air conditioner according to claim 1, wherein when the detected value of the indoor heat exchange temperature sensor becomes equal to or lower than a predetermined temperature at which the release is released, the indoor controller sends a release release signal to the outdoor blower speed control means. An air conditioner comprising: means for sending; and means for gradually increasing the rotation speed of the outdoor fan from a minimum speed operation to a normal operation speed in response to the release cancel signal. 5. A refrigeration cycle in which a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, an indoor heat exchanger, and the like are connected, an outdoor blower having a variable speed, and an outdoor blower speed for controlling the speed of the outdoor blower. Control means, and a low-pressure switch for detecting a low-pressure pressure of the refrigeration cycle. When the low-pressure switch is operated, the compressor is stopped, and when restarted after a predetermined time, the speed of the outdoor blower is previously started. An air conditioner comprising means for controlling a rotation value lower than a rotation speed at the time. 6. A refrigeration cycle in which a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, an indoor heat exchanger, and the like are connected, an outdoor blower having a variable speed, and the liquid side during cooling of the refrigeration cycle being compressed. Along with the suction side of the machine, a bypass circuit via a pressure reducing device is provided on the way, and a saturation temperature sensor for detecting the refrigerant temperature is provided in the bypass circuit, and the saturation temperature sensor detects a predetermined value or less. When the compressor is stopped and restarted after a predetermined period of time, the air conditioner further includes means for controlling the speed of the outdoor blower to a rotation value lower than the rotation speed at the time of the previous start.