JPH08166174A - Air conditioner - Google Patents

Abstract

PURPOSE: To suppress or effectively prevent a rise in a pressure on the high pressure side of a refrigerating cycle above a prescribed pressure or a fall of a pressure on the low pressure side below a prescribed pressure and thereby to control the number of revolutions of an outdoor blower for a prescribed time to be an appropriate number of revolutions corresponding to an outdoor load. CONSTITUTION: An air conditioner has a refrigerating cycle connecting a compressor 3, a four-way valve 4, an outdoor heat exchanger 6, an expansion valve 7, an indoor heat exchanger 9, etc., an outdoor blower 5 of which the speed can be varied, an outdoor controller 15 which controls the speed of revolution of the outdoor blower 5 in a range from the highest speed to the lowest and also has the lowest speed values in a plurality of grades from high to low, an indoor heat exchanger temperature sensor 13 which detects the temperature of the indoor heat exchanger 9 and an indoor controller 14 which sends a release signal to the outdoor controller 15 when a detected value of the indoor heat exchanger temperature sensor reaches a prescribed temperature or above at the time of a heating operation. The outdoor controller 15 is provided with a means which selects a speed of the outdoor blower 5 from the lowest speed values set beforehand and determines it when this controller receives the release signal from the indoor controller 14 in heating.

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 equipped with an outdoor blower whose speed can be varied, and more particularly, to control the number of revolutions of the outdoor blower per predetermined time to an appropriate number of revolutions according to the outdoor load. Regarding the air conditioner.

[0002]

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

This release control is released when the temperature of the indoor heat exchanger drops 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 is performed. If the minimum rotation speed of the outdoor blower is too low, the amount of vaporized liquid refrigerant in the outdoor heat exchanger decreases, and liquid refrigerant that the liquid refrigerant returns to the compressor tends to occur, reducing the reliability and durability of the refrigeration cycle. There is a problem to do.

On the contrary, if the minimum rotation speed of the outdoor blower is too high when the load of the outdoor heat exchanger is high, the amount of heat absorbed by the outdoor heat exchanger increases, and by extension, the indoor heat exchanger. Since the amount of heat radiation increases, the high pressure side of the refrigeration cycle rises and the high pressure switch operates, making it easy to stop the compressor. For this reason, since the high-voltage switch is repeatedly turned on and off 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 deteriorate.

Further, 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 set to the value before the release control as shown by a curve A in FIG. A certain amount α than the rotation speed T1
Suddenly increased to a low speed T2, and then
After a predetermined time ta, a predetermined amount α is increased to return to the rotational speed T1 before the release control is started.

That is, after the release control is released, the number of rotations of the outdoor blower is increased to T2 all at once, so that the pressure fluctuation of the refrigeration cycle is large and the stability of the refrigeration cycle is low.

Further, 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 increase in the high pressure, and the maximum rotation speed is also maintained at the restart. 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 unlikely to rise even if it is started up several times, and the above-mentioned outdoor When the blower is started at the maximum speed, the flow rate of the liquid refrigerant that is liquefied in the outdoor heat exchanger increases, but the flow rate of the refrigerant that is radiated and condensed in the indoor heat exchanger is small, so it is even more difficult for the low-pressure side to rise. As a result, there is a case where the low pressure switch operates due to an abnormal decrease on the low pressure side to abnormally stop the compressor.

Therefore, the present invention has been made in consideration of such circumstances, and an object thereof is to increase the pressure on the high pressure side of the refrigeration cycle to a predetermined pressure or higher, or to reduce the pressure on the low pressure side to a predetermined pressure or lower. The air conditioner that suppresses or effectively prevents this and controls the number of rotations of the outdoor blower per predetermined time to an appropriate number of rotations according to the outdoor load, thereby achieving both reliability and durability. To provide.

[0011]

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

The invention according to claim 1 of the present application (hereinafter, referred to as the first
Invention), 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 with variable speed, and the rotation speed of this outdoor blower from the highest speed. An outdoor blower speed control unit that controls the lowest speed value to multiple levels from high to low, an indoor heat exchanger temperature sensor that detects the temperature of the indoor heat exchanger, and an indoor heat during heating operation. An indoor controller that sends a release signal to the outdoor blower speed control means when the detected value of the exchange temperature sensor reaches a predetermined temperature or higher, and an outdoor controller that receives a release signal from the indoor controller during heating. Means for selecting and determining the speed of the blower from a preset minimum speed.

The invention according to claim 2 of the present application (hereinafter referred to as the second invention) is the operation of the compressor in the air conditioner according to claim 1 when a predetermined high pressure of the refrigeration cycle is detected. And a means for operating the minimum speed value of the outdoor blower at the time of heating at a rotation speed setting value lower than the minimum speed setting value before the operation when the high pressure switch operates. Is characterized by.

Further, the invention according to claim 3 of the present application (hereinafter referred to as the third invention) is the air conditioner according to claim 1, wherein the outdoor heat exchanger is provided with a temperature sensor, and when heating,
The minimum speed value of the outdoor blower is determined based on the detection value of the outdoor heat temperature sensor before the compressor is started, and when this outdoor heat exchange temperature sensor is equal to or higher than the predetermined value, the minimum speed of the outdoor blower is set to the lower side. When the set value is less than a predetermined value, a means for setting the set value on the higher side is provided.

Furthermore, the invention according to claim 4 of the present application (hereinafter referred to as the fourth invention) is, in the air conditioner according to claim 1, a value detected by 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 this release release signal gradually increases the rotation speed of the outdoor fan from the lowest speed operation to the normal operation speed. And a means for making it possible.

The invention according to claim 5 of the present application (hereinafter referred to as the fifth invention) is 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. , 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 of the refrigeration cycle, and when the low pressure switch is operated, the compressor is operated. On the other hand, when it is restarted after a predetermined time while stopping, a means for controlling the speed of the outdoor blower to a rotational numerical value lower than the rotational speed at the previous startup is provided.

Further, the invention according to claim 6 of the present application (hereinafter referred to as the sixth invention) is 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 and a cooling liquid side of the refrigeration cycle are connected to the suction side of the compressor, and a bypass circuit via a pressure reducing device is provided on the way to detect the refrigerant temperature. When the saturation temperature sensor detects a temperature equal to or lower than a predetermined value, the compressor is stopped and restarted after a predetermined time, and the speed of the outdoor blower is set to be lower than the rotation speed at the time of the previous start. It is characterized in that it is provided with means for controlling to a low rotational speed value.

[0018]

[Action]

<First Invention> When the control means receives a release signal from the indoor controller during the heating operation, the control means controls the rotation speed of the outdoor blower to a preset minimum speed value. This reduces the amount of refrigerant liquefied in the outdoor heat exchanger, so when the outdoor load is low, the amount of refrigerant radiated in the indoor heat exchanger is also small, so the cycle pressure stabilizes or is released. The signal is released and the outdoor blower is operated at full speed again.

Therefore, since the outdoor blower can be operated at an appropriate rotational speed according to the outdoor load, the 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> During heating operation, even if the control means receives the release signal and controls the outdoor blower to the minimum rotation speed, the high pressure continues to rise when the outdoor load is high, so the high voltage switch Operates to temporarily stop the operation of the compressor and stop the pressure increase on the high pressure side. Along with this, 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 is restored and the compressor is restarted. However, the high pressure does not reach the predetermined high pressure immediately. Therefore, it is possible to effectively prevent short intermittent operation of the compressor, and it is possible to improve both reliability and durability of the refrigeration cycle.

<Third invention> Since 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 air blower is selected based on the detected outdoor air temperature, the outdoor air blower of this outdoor air blower is selected. The rotation speed can be controlled to an appropriate speed according to the outdoor load. Therefore, the pressure increase on the high-pressure side of the refrigeration cycle can be suppressed, so that both 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 lowest speed to the normal speed without increasing at once, so that 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. Also, when restarting this compressor, the rotation speed of the outdoor blower is controlled to be lower than the rotation speed at the previous startup, so the liquefaction amount of the refrigerant condensed and liquefied 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 expensive because it is not simple in structure and requires high precision. However, the saturation temperature sensor is an inexpensive temperature sensor, so that the cost can be reduced.

[0026]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 9, the same or corresponding parts are designated 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 is a compressor 3 whose rotation speed is controlled by an inverter 2.
A four-way valve 4, an outdoor heat exchanger 6 having an outdoor blower 5 with variable rotation speed 6, an expansion valve 7 and an indoor heat exchanger 9 having an indoor blower 8 are sequentially connected by a refrigerant pipe 10 to form a refrigeration cycle. There is.

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

In the refrigeration cycle, the high pressure switch 11 is provided on the high pressure side of the compressor 3, which is the high pressure side, while the outdoor heat exchanger sensor 12 for detecting the temperature of the outdoor heat exchanger 6 and the indoor heat exchanger 9 are provided. An indoor heat exchange sensor 13 for detecting the temperature is provided, and the indoor heat exchange sensor 13 and the indoor blower 8 are electrically connected to an indoor controller 14 including a microprocessor or the like via a signal line.

The indoor controller 14 is further electrically connected to an outdoor controller 15 composed of a microprocessor and the like, and the indoor heat exchanger 9 read from the indoor heat exchange sensor 13 is read.
2, the release signal is sent to the outdoor controller 15 when the temperature rises above the release temperature of 60 ° C. as shown in FIG. 2, while the release signal is released below the release release temperature of 58 ° C. The output of the signal is stopped.

Further, the indoor controller 14 reads the room temperature detected value from a room temperature sensor (not shown), compares the room temperature detected value with a room temperature set value set by a remote controller (not shown), etc., and sets the operation command frequency to zero the deviation. It also has a function of giving a signal to the inverter 2 via the outdoor controller 15 to control the number of revolutions of the compressor 3 per predetermined time, that is, the rotation speed, so that the room temperature detection value becomes a set value.

On the other hand, the outdoor controller 15 includes 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 in stages from the first rotation speed, which is the lowest rotation speed, to the 16th speed, which is the highest rotation speed, and sets the lowest rotation speed value from the eighth speed to the first speed during the heating operation. Control is performed during the period, the initial value of the minimum rotation speed value is set to the eighth speed, and control is performed according to the procedure of the processing program shown in the flowchart of FIG.

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

First, in S1, the outdoor controller 15 sets the four-way valve 4
It is judged from the switching angle of whether the refrigeration cycle is currently in heating operation, and if YES, whether the high pressure switch 11 is operating in S2, that is, the high pressure on the refrigerant discharge side of the compressor 3 is equal to or higher than a predetermined pressure. If YES, the process proceeds to S3, and if NO, the process proceeds to S4.

That is, when 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 the high pressure switch 11 operates, but in this case, at S3. The operation of the compressor 3 is stopped to prevent damage to 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 during the previous operation.

Therefore, if the number of revolutions of the outdoor blower 5 during the previous operation is, for example, the 8th speed, the reception of the release signal this time reduces the speed to the 7th speed, which is one speed lower than the 8th speed. The speed is gradually reduced in accordance with the length of the signal reception time.

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

Therefore, it is possible to effectively prevent a 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 compressor 3 is restarted.

On the other hand, when the high voltage switch 11 is not operating in S2 due to a low outdoor load, it is determined in S4 whether or not the 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 step S5, it is further determined whether or not the release control is currently in progress. If YES, that is, if the release control is in progress, the process returns to step S1 and the above steps are repeated.

However, when the release control is not currently being performed in S5, the release signal received in S4 is the first time, so 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 high pressure side of the discharge side of the compressor 3 to which this refrigerant returns can be lowered.
Return to 1 and repeat the following steps.

On the other hand, when the release control is being performed in S6, the release signal has not been received in the preceding stage S4, so it is determined that the release signal has been released, and the rotation speed of the outdoor blower 5 is set to the maximum in S8. The speed is restored, the normal heating operation is resumed, and then the procedure returns to S1 again, and the above steps are repeated.

However, if the release control is not being performed in S6, it is determined in S9 whether or not the release signal is continuously received for a predetermined time of, for example, 10 minutes. If NO, the process returns to S1 again, and if YES. Raises the minimum speed value of the outdoor blower 5 to the first 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 again, 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 step by step every minute and does not return at once as in the conventional example, hunting of the refrigeration cycle can be prevented and stabilized.

Therefore, according to the present embodiment, when the outdoor controller 15 receives the release signal, the outdoor blower 5
In addition to reducing the rotation speed of to the minimum speed value, while the release signal is being received, the minimum speed value of the outdoor blower 5 is gradually reduced gradually with the passage 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, it is possible to effectively prevent the liquid bag from being generated in the compressor 3 because the minimum speed value of the outdoor blower 5 is excessively reduced at once.

Further, when the outdoor load is high, the outdoor blower 5
Since it is possible to effectively prevent the high-voltage switch 11 from being interrupted in a short time because the minimum speed is too high, it is possible to improve both reliability and durability of the refrigeration cycle.

FIG. 4 is a flow chart showing another example of the method for controlling the rotation speed of the outdoor blower 5, in which the temperature of the outdoor heat exchanger 6 before the start of the compressor 3 is 10 during heating operation. When the temperature is equal to or higher than a predetermined value of ° C, the minimum speed of the outdoor blower 5 is reduced by one speed, and when the temperature is lower than the predetermined value of 10 ° C, the minimum speed value of the outdoor blower 5 is set to, for example, the fifth speed. It is characterized in that it is controlled.

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

FIG. 5 shows that when the release control is released during the heating operation, the predetermined speed β is gradually increased every predetermined time t without increasing the minimum rotation speed L of the outdoor blower 6 to the rotation speed H during the normal operation. The feature is that it gradually increases.

According to this, since the minimum rotation speed L of the outdoor blower 5 is gradually increased to the rotation speed H during the normal operation, the fluctuation of the cycle pressure can be suppressed to a small extent. Therefore, 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 the refrigerant suction side, which is the low pressure side of the compressor 3, detects a pressure below a predetermined pressure. 1 is characterized in that after the operation of the compressor 3 is stopped at that time, the rotation speed of the outdoor blower 5 is reduced by the outdoor controller 15a to be lower than the rotation speed at the time of the previous start, and other than this, FIG. Since it is almost the same as the embodiment shown in, the same or corresponding parts are denoted by the same reference numerals or omitted in the drawings, and the duplicated description thereof will be omitted.

That is, this embodiment is difficult to start when the cooling operation is started when the outside air temperature is relatively low, because the pressure on the low pressure side of the refrigeration cycle does not increase immediately, but in such a case There is a feature in the method of controlling the rotation speed of the outdoor blower 5 in order to facilitate the above.

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 when the cooling operation is started when the refrigerant in the indoor heat exchanger 9 is sleeping, Even if the compressor 3 is started up once or twice as shown in FIG. 7, the low-pressure side is below the operating point of the low-pressure switch 16, so the low-pressure switch 16 operates and the compressor 3 cannot be started up easily. .

Therefore, in such a case, as shown in FIGS. 7 and 8, the outdoor controller 15 controls the number of rotations of the outdoor blower 5 per predetermined time, that is, the rotation speed, to the predetermined number of rotations for each operation of the low pressure switch 16. The high pressure side is gradually increased and the low pressure side is gradually increased by gradually reducing each by γ, and the compressor 3 is started. However, the low-voltage switch 16
When the number of times of operations reaches 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 operates 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 boosted. Thus, the low pressure side can be boosted to start the cooling operation.

Further, when the low pressure switch 16 is operated a predetermined number of times or more due to some abnormal low pressure, the compressor is stopped from being started, so that the failure of the refrigeration cycle equipment can be prevented in advance.

FIG. 9 shows a refrigerating cycle according to still another embodiment of the present invention. In this embodiment, the low-pressure switch 16 shown in FIG. 6 is omitted, but the outdoor heat exchange for condensing during the cooling operation is performed. A bypass passage 17 that connects the refrigerant outlet side of the compressor 6 to the refrigerant inlet side of the compressor 3 is provided, and a capillary tube 18 that is a refrigerant pressure reducer and a saturation temperature sensor 19 are provided in the bypass passage 17. Is characterized by.

Generally, the low-pressure switch 16 is required to have high accuracy in order to detect low pressure, and is expensive like a pressure switch in general, but the saturation temperature sensor 19 can detect the temperature of the liquid refrigerant as the pressure on the low-pressure side. It is a temperature sensor that can be manufactured. Generally, the temperature sensor has a simpler structure than a pressure switch in general, and is therefore inexpensive. Therefore, the cost can be reduced.

[0059]

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

Therefore, since the outdoor blower can be operated at an appropriate rotation speed according to the load, the 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 reduced. Can be planned.

Further, in the second invention of the present application, even when the release signal is received by the control means during heating operation and the outdoor blower is controlled to the minimum rotation speed, the high pressure continues to rise when the outdoor load is high. The high pressure switch operates to temporarily stop the operation of the compressor and stop the pressure increase on the high pressure side. Along with this, 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 is restored and the compressor is restarted. However, the high pressure does not reach the predetermined high pressure immediately. Therefore, it is possible to effectively prevent short intermittent operation of the compressor, and it is possible to improve both reliability and durability of the refrigeration cycle.

Furthermore, 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. Therefore, the pressure increase on the high-pressure side of the refrigeration cycle can be suppressed, so that both reliability and durability of the refrigeration cycle can be improved.

Furthermore, 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 lowest speed to the normal speed without being increased at once, so that cycle fluctuation (hunting) is suppressed. Can be stabilized.

Further, in the fifth aspect of the present invention, when the low-pressure side pressure is lowered for some reason at the time of starting the cooling operation, the low-pressure switch operates to stop the compressor, so that the failure of the cycle equipment can be prevented. You can Also, when restarting this compressor, the rotation speed of the outdoor blower is controlled to be lower than the rotation speed at the previous startup, so the liquefaction amount of the refrigerant condensed and liquefied 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 expensive because it is not simple in structure and requires high accuracy, but the saturation temperature sensor is an inexpensive temperature sensor.
The cost can be reduced.

[Brief description of 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 thresholds of a release signal and a release release signal output from the indoor controller shown in FIG.

FIG. 3 is a flowchart showing an example of a method for controlling an outdoor blower rotation speed of the outdoor controller shown in FIG.

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

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

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

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

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

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 the outdoor blower at the time of releasing the release control in the conventional air conditioner.

[Explanation 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 pipe 11 high pressure switch 12 outdoor heat exchange sensor 13 indoor heat Exchange sensor 13 Indoor controller 15, 15a Outdoor controller 16 Low-voltage switch 17 Bypass passage 18 Capillary tube 19 Saturation temperature sensor

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yasushi Yamanashi 336 Tatehara, Fuji City, Shizuoka Prefecture Toshiba Corporation Fuji Factory

Claims (6)

[Claims] 1. 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, and the rotation speed of this outdoor blower is from the highest speed to the lowest. The outdoor blower speed control means that controls the speed to a high speed and has a plurality of levels of this minimum speed value from high to low, an indoor heat exchanger temperature sensor that detects the temperature of the indoor heat exchanger, and an indoor heat exchanger during heating operation. An indoor controller that sends a release signal to the outdoor blower speed control means when the detected value of the temperature sensor reaches a predetermined temperature or more, and an outdoor blower that receives a release signal from the indoor controller during heating. An air conditioner having means for selecting and determining the speed from the minimum speed set in advance. 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 operates, the outdoor during heating. An air conditioner comprising means for operating the minimum speed value of the blower at a rotational speed setting value lower than the minimum speed setting value before the operation. 3. The air conditioner according to claim 1, wherein the outdoor heat exchanger is provided with a temperature sensor, and during heating, the minimum speed value of the outdoor blower is set to the detected value of the outdoor heat temperature sensor before the compressor is started. Based on this outdoor heat exchange temperature sensor,
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 to a higher set 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 is equal to or lower than a predetermined temperature for releasing the release, the indoor controller sends a release release signal to the outdoor blower speed control means. An air conditioner comprising: a sending means and a means for gradually increasing the rotation speed of the outdoor fan from the lowest speed operation to the normal operation speed by the release release signal. 5. 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 with variable speed, and an outdoor blower speed for controlling the speed of this outdoor blower. A control means and a low pressure switch for detecting a low pressure of the refrigeration cycle are provided, and when the low pressure switch operates, the compressor is stopped, while the compressor is restarted after a predetermined time, the speed of the outdoor blower is previously started. An air conditioner comprising means for controlling the rotational speed to be lower than the rotational speed at time. 6. 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 with a variable speed, and the liquid side during cooling of the refrigeration cycle is compressed. A bypass circuit that communicates with the suction side of the machine and a decompression device is provided on the way, and a saturation temperature sensor for detecting the refrigerant temperature is provided in the bypass circuit.The saturation temperature sensor detects a predetermined value or less. At this time, when the compressor is stopped and restarted after a predetermined time, a unit for controlling the speed of the outdoor blower to a rotational speed lower than the rotational speed at the previous startup is provided.