JPH11211247A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance reliability of a refrigeration cycle by decreasing the r.p.m. of a compressor before decreasing the r.p.m. of the condenser and a fan and preventing over pressure rise on the high pressure side thereby suppressing abnormal stop of a compressor, and the like, or release control. SOLUTION: A control section 31 performs general control of an air conditioner and a second speed control circuit 30 sets the rotational speed of an outdoor fan motor 8M at a level corresponding to a command from the control section 31 at the time of power supply voltage control for the motor 8M. A first speed control circuit 29 sets the rotational speed of an indoor fan motor 4M at a level corresponding to a command from the control section 31 at the time of power supply voltage control for the motor 4M. An indoor tan control means 31a at the control section 31 decreases the r.p.m. of a compressor 2 before the r.p.m. of an indoor tan 4 for main and sub-indoor heat exchangers 5, 6 serving as a condenser at the time of heating operation is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to at least R32
The present invention relates to an air conditioner that uses a high-pressure refrigerant such as a mixed refrigerant containing (difluoromethane), and more particularly to an air conditioner with an improved control method for reducing the amount of air blown to a condenser.

[0002]

2. Description of the Related Art Generally, an air conditioner has a refrigerating cycle in which a compressor, an outdoor heat exchanger, a decompressor, and an indoor heat exchanger are sequentially communicated to circulate a refrigerant, so that the air conditioner can be freely cooled and heated. That is, by controlling the circulation direction of the refrigerant, the outdoor heat exchanger serves as an evaporator, and the indoor heat exchanger functions as a condenser, whereby the heating operation can be performed, while the outdoor heat exchanger serves as a condenser, The cooling operation can be performed by making each indoor heat exchanger function as an evaporator.

[0003] In this type of conventional air conditioner,
When the condensing temperature of the indoor heat exchanger functioning as a condenser during the heating operation is high, if there is a rotation speed reduction command from a remote controller or the like to reduce the air flow of the indoor fan,
It merely reduces the air flow of the indoor fan and does not lower the operating frequency of the compressor, or simultaneously reduces the air flow of the indoor fan and lowers the operating frequency of the compressor. It's just

[0004]

However, such a conventional air conditioner has at least R3 as a refrigerant.
When a high-pressure refrigerant such as a mixed refrigerant containing 2 (difluoromethane) is used, when the condensing temperature of the indoor heat exchanger functioning as a condenser during the heating operation is high, for example, a "strong wind" mode Since there was an indoor fan rotation speed reduction command to reduce the air flow of the indoor fan such as in the `` light wind '' mode, if only the air flow of the indoor fan was immediately reduced according to the rotation speed reduction command, Since the decompression of the indoor heat exchanger, which is a condenser that has been cooled and depressurized by the ventilation of the indoor fan, is immediately stopped, the indoor heat exchanger is maintained at a high pressure. Also, if the rotation speed of the compressor, that is, the operating frequency is not reduced when reducing the air flow rate of the indoor fan, the indoor heat exchange functioning as a condenser during the heating operation due to an excessive increase in the high pressure side pressure of the refrigeration cycle. There is a risk that the pressure of the air conditioner will suddenly rise excessively, causing breakdown of the compressor, failure of refrigeration cycle components, and the like, thus causing a problem of lowering the reliability of the air conditioner.

When the operating frequency of the compressor to be operated in accordance with the various air flow rates of the indoor fan is set in advance, the required air flow rate to be reduced is selected to reduce the air flow rate. Even when the operating frequency of the compressor is reduced at the same time, the pressure on the high-pressure side transiently rises until the effect of reducing the operating frequency of the compressor occurs.

[0006] These problems occur not only in the heating operation in which the indoor heat exchanger functions as a condenser, but also in the cooling operation in which the outdoor heat exchanger functions as a condenser.

Accordingly, the present invention has been made in view of such circumstances, and its object is to provide a high-pressure system for cooling and heating operations and for reducing the amount of air blown to the outdoor and indoor heat exchangers functioning as condensers. It is an object of the present invention to provide an air conditioner that can prevent an excessive rise in side pressure, reduce abnormal stoppage of a compressor or the like and release control, and improve reliability of a refrigeration cycle.

[0008]

An air conditioner according to the present invention has a refrigeration cycle that circulates a refrigerant by sequentially communicating a compressor, a condenser, a decompressor, and an evaporator whose rotation speed is freely controlled. , A condenser blower capable of controlling the number of rotations to blow to the condenser, and in the air conditioner having :, when reducing the number of rotations per unit time of the condenser blower, before the unit of the compressor, Control means for reducing the number of revolutions per hour is provided.

According to the present invention, when the number of rotations of the condenser blower per unit time (hereinafter simply referred to as "number of rotations") is reduced by the control means, the number of rotations of the compressor is reduced before that. Since the refrigerant discharge pressure of the compressor is reduced in advance, it is possible to prevent an excessive increase in the high-pressure side pressure of the refrigeration cycle.

[0010] For this reason, excessive rise of the pressure of the condenser, abnormal stop of the compressor, and high pressure release control are reduced, and the reliability of the refrigeration cycle can be improved.

[0011] The air conditioner according to the second aspect of the present invention is characterized in that:
The control means reduces the operating frequency of the compressor to an operating frequency set in advance corresponding to the amount of air blown by the condenser blower to be reduced, or the difference between the set operating frequency and the maximum operating frequency. It is configured to reduce the air flow rate of the condenser blower after the frequency is reduced to an intermediate frequency or lower.

According to the present invention, when the operating frequency of the compressor to be operated for each air flow of the condenser blower is set in advance in the invention according to the first aspect, the control means controls the operating frequency. After reducing the operating frequency of the compressor to an operating frequency that is set in advance corresponding to the amount of air to be reduced, the control unit decreases the operating frequency to the amount of air of the condenser blower corresponding to the set operating frequency. Let it.

Alternatively, the control means lowers the operating frequency of the compressor to a frequency lower than an intermediate frequency between the set operating frequency and the maximum operating frequency, and then lowers the air flow to the amount of air to be reduced. .

According to the present invention, similarly to the first aspect of the present invention, after the operating frequency of the compressor, that is, the number of revolutions, is reduced, the amount of air is reduced by decreasing the number of revolutions of the condenser blower. Excessive increase in the pressure on the high pressure side of the cycle is prevented, so that excessive increase in the pressure of the condenser, abnormal stop of the compressor, and high pressure release control are reduced, and the reliability of the refrigeration cycle can be improved.

An air conditioner according to a third aspect of the present invention is
The condenser serves as an indoor heat exchanger during the heating operation.

According to the present invention, by using the control means according to the first or second aspect, a heating operation in which the pressure of the indoor heat exchanger does not excessively increase and the temperature fluctuation is small during heating can be performed.

An air conditioner according to a fourth aspect of the present invention is
The refrigerant is a high-pressure refrigerant having a saturation pressure at 50 ° C. of 2500 KPa or more.

According to the present invention, since the refrigerant is a high-pressure refrigerant having a saturation pressure at 50 ° C. of 2500 KPa or more, the high-pressure side pressure of the refrigeration cycle may rise excessively. By using the control means, the excessive rise can be prevented.

An air conditioner according to a fifth aspect of the present invention is
The refrigerant is a mixed refrigerant containing at least R32 (difluoromethane).

According to the present invention, since the high-pressure refrigerant is a mixed refrigerant containing at least R32, the same operation and effect as those of the first aspect can be obtained by the air conditioner using this mixed refrigerant.

An air conditioner according to a sixth aspect of the present invention is
The heating capacity is set to 6.0 KW or more.

According to the present invention, the heating capacity is 6.0 KW
An excessive increase in the high-pressure side pressure in the high-output air conditioner described above can be effectively prevented.

The air conditioner according to the invention of claim 7 is:
A refrigeration cycle that circulates refrigerant by sequentially communicating a compressor, an outdoor heat exchanger, a decompressor, and an indoor heat exchanger that can control the rotation speed, and an indoor fan that can control the rotation speed to blow air to the indoor heat exchanger; In the air conditioner having, an indoor heat exchange temperature sensor for detecting the temperature of the indoor heat exchanger during the heating operation, and when reducing the number of rotations per unit time of the indoor fan, the speed of reducing the number of rotations A control means for delaying when the detection value from the indoor heat exchange temperature sensor is higher than a predetermined value than when the detection value is low.

According to this invention, when the temperature detected by the indoor heat exchange temperature sensor for detecting the temperature of the indoor heat exchanger functioning as a condenser during the heating operation is higher than a predetermined value, the indoor heat exchanger is in a high pressure state. It is in. Therefore, at this time, the rotation speed of the indoor fan is reduced immediately without decreasing the rotation speed of the indoor fan according to a command from the remote controller or the like to reduce the rotation speed of the indoor fan per unit time (hereinafter, simply referred to as the rotation speed). Delayed by control means. This allows
The action of cooling the indoor heat exchanger, which is a condenser, and depressurizing it by blowing air from the indoor fan does not stop immediately but becomes longer by the delay time, so that an excessive increase in the pressure of the indoor heat exchanger is prevented. Can be. For this reason, it is possible to prevent a transient increase in pressure on the high pressure side (discharge side) of the compressor, and to improve the pressure resistance of the refrigeration cycle.

The air conditioner according to the invention of claim 8 is:
A correction means for correcting a detection value detected by the indoor heat exchange temperature sensor and given to the control means by a correction value for compensating for a delay in the temperature detection operation by the indoor heat exchange temperature sensor. .

According to the present invention, the detection value detected by the indoor heat exchange temperature sensor is corrected by the correction value for compensating for the delay of the detection operation of the indoor heat exchange temperature sensor, and is then given to the control means. It is possible to compensate for a delay in controlling the rotational speeds of the compressor and the indoor fan controlled by the control means, and to improve the control accuracy.

[0027] An air conditioner according to a ninth aspect of the present invention provides:
A refrigeration cycle that circulates refrigerant by sequentially communicating a compressor, an outdoor heat exchanger, a decompressor, and an indoor heat exchanger that can control the rotation speed, and an outdoor fan that can control the rotation speed to blow air to the outdoor heat exchanger. In the air conditioner having an outdoor heat exchange temperature sensor that detects the temperature of the outdoor heat exchanger during cooling operation, when reducing the number of rotations per unit time of the outdoor fan, the speed at which the number of rotations is reduced Further, a control means is provided for delaying when the detection value from the outdoor heat exchange temperature sensor is higher than a predetermined value than when it is low.

According to the present invention, when the temperature detected by the outdoor heat exchange temperature sensor for detecting the temperature of the outdoor heat exchanger functioning as a condenser during the cooling operation is higher than a predetermined value, the outdoor heat exchanger is in a high pressure state. It is in. Therefore, at this time, in accordance with the command to decrease the rotation speed of the outdoor fan, the rotation speed of the outdoor fan is delayed by the control means without immediately decreasing the rotation speed of the outdoor fan. As a result, the action of cooling and reducing the pressure of the outdoor heat exchanger, which is a condenser, due to the air blown from the outdoor fan does not stop immediately, but becomes longer by the delay time. Can be prevented. For this reason, it is possible to prevent a transient increase in pressure on the high pressure side (discharge side) of the compressor, and to improve the pressure resistance of the refrigeration cycle.

[0029] In the air conditioner according to the tenth aspect of the present invention, the detection value detected by the outdoor heat exchange temperature sensor and given to the control means is corrected to compensate for a delay in the temperature detection operation by the outdoor heat exchange temperature sensor. The air conditioner according to claim 9, further comprising a correction unit configured to correct the value based on the value.

According to the present invention, the detection value detected by the outdoor heat exchange temperature sensor is corrected by the correction value for compensating for the delay in the detection operation of the outdoor heat exchange temperature sensor, and is then given to the control means. It is possible to compensate for a delay in controlling the rotational speeds of the compressor and the outdoor fan controlled by the control means, thereby improving the control accuracy.

[0031]

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

FIG. 3 is a refrigeration cycle diagram of the air conditioner 1 according to the first embodiment of the present invention. The air conditioner 1 has a compressor 2, a four-way valve 3, a main indoor heat exchanger 5 and an auxiliary indoor heat exchanger 6 having an indoor fan 4, an electric expansion valve 7 as a decompressor, and an outdoor having an outdoor fan 8. A refrigeration cycle for reversibly circulating the high-pressure refrigerant by sequentially connecting the heat exchangers 9 in this order through the refrigerant pipes 10 constitutes a refrigeration cycle.

As the high-pressure refrigerant, the saturation pressure at 50 ° C. is 2
A refrigerant having a pressure of 500 MPa (kilopascal) or more is used, and a mixed refrigerant containing at least R32 (difluoromethane), for example, a refrigerant in which R32 and R125 (pentafluoroethane) are mixed by about 50% by weight is used. In FIG. 3, 9a is an outdoor heat exchange temperature sensor for detecting the temperature of the outdoor heat exchanger 9, 11 is an indoor unit,
2 is an outdoor unit.

The refrigeration cycle is operated by switching the four-way valve 3 to circulate the refrigerant in the direction of the solid line arrow in the drawing, and is operated by cooling, and by circulating the refrigerant in the direction of the broken line arrow in the drawing, heating operation is performed. During the heating operation, the main and auxiliary indoor heat exchangers 5 and 6 function as condensers.
Functions as a condenser blower. The indoor fan 4 is driven by an indoor fan motor 4M.

FIG. 4 is a side sectional view of the indoor unit 11. The indoor unit 11 has a suction port 13 for sucking room air on the front surface, and a suction port 14 for room air on the top surface.
And an outlet 15 for air-conditioning air (cooling air, dehumidified air, heating air, etc.) at the lower part of the front surface.

In the indoor unit 11, the suction port 1 is provided.
An air passage 16 that connects the air outlets 3 and 14 with the air outlet 15 is formed. In the ventilation path 16, a dustproof (and deodorizing) air filter 17 is provided inside the suction ports 13 and 14, and the main indoor heat exchanger 5 and the auxiliary chamber are provided inside the air filter 17 (downstream side). A heat exchanger 6 is provided. Inside these two heat exchangers 5, 6, a horizontal flow type indoor fan 4 is arranged.

The main indoor heat exchanger 5 is divided into a first heat exchanger 5a and a second heat exchanger 5b.
b is arranged in an inverted V shape so as to surround the indoor fan 4.
The first heat exchanger 5a faces the suction port 13 on the front face, and the second heat exchanger 5b faces the suction port 14 on the top face. The auxiliary indoor heat exchanger 6 is arranged between the second heat exchanger 5b and the upper surface suction port 14, that is, at a position on the windward side above the second heat exchanger 5b in the indoor air suction flow path. You.

An electric heater 18 and a drainage member 19 are provided in a space between the first and second heat exchangers 5a and 5b and the indoor fan 4. The electric heater 18 is for heating the air that has passed through the first and second heat exchangers 5a and 5b as necessary. The drainage member 19 prevents the drain from directly falling on the electric heater 18 even if the drain drips from the first and second heat exchangers 5a and 5b.

The drain receiving portion 2 is provided below the first heat exchanger 5a.
0 is formed. A drain receiving portion 21 is also formed below the second heat exchanger 5b and the auxiliary indoor heat exchanger 6.

Although the radiation fins of the first heat exchanger 5a and the radiation fins of the second heat exchanger 5b are in contact with each other,
A gap is secured between the radiating fins of the heat exchanger 5b and the radiating fins of the auxiliary indoor heat exchanger 6, so that the two radiating fins are in non-contact, that is, in a thermally separated state.

When the indoor fan 4 rotates, indoor air is sucked into the indoor unit 11 through the front suction port 13 and the top suction port 14, respectively. Suction air from the suction port 13 passes through the air filter 17 and further passes through the first heat exchanger 5a to the indoor fan 4 side.
After the intake air from the air filter 3 is purified by passing through the air filter 17, the air first passes through the auxiliary indoor heat exchanger 6, and then the second air
It flows to the indoor fan 4 side through the heat exchanger 5b.

In the ventilation path 16, a left / right air direction changing plate 22 is provided at a position facing the outlet 15 on the downstream side of the indoor fan 4. The left and right wind direction change plates 22 are for setting the direction of the blown wind in the left and right direction of the indoor unit 11, and are motor-driven.

A plurality of, for example, a pair of upper and lower wind direction change plates 23, 23 are provided vertically below the left and right wind direction change plates 22. The vertical wind direction change plates 23, 23 are driven by a single motor in conjunction with each other, and rotate clockwise during operation to open the air outlet 15 during operation, and change the direction of the blown air in the vertical direction of the indoor unit 11. In addition, when the operation is stopped, it rotates counterclockwise to close the air outlet 15 and functions to prevent dust from entering the indoor unit 11.

The auxiliary indoor heat exchanger temperature sensor 24 is attached to the heat exchange pipe on the outlet side of the auxiliary indoor heat exchanger 6, and the main indoor heat exchanger is attached to the heat exchange pipe in the middle part of the first heat exchanger 5a. The temperature sensor 25 is attached. Further, an indoor temperature sensor 26 (see FIG. 5) is provided in the indoor air suction passage from the front inlet 13 to the main indoor heat exchanger 5.
Is provided.

FIG. 5 is a schematic diagram showing the refrigeration cycle and the control system. As shown in FIG. 5, a commercial AC power supply 27 includes an inverter circuit 28, a first speed control circuit 2 and a second speed control circuit 2.
9 and 30 and a control unit 31 as control means are connected. Further, the control unit 31 includes an inverter circuit 28,
First and second speed control circuits 29, 30, wind direction changing plate motors 22M, 23M, auxiliary, main room heat exchange temperature sensor 2
4, 25, the indoor temperature sensor 26, the electric heater 18, the four-way valve 3, the electric expansion valve 7, the outdoor heat exchange temperature sensor 9a, and the light receiving section 32 are electrically connected.

The inverter circuit 28 rectifies the AC power supply voltage into a direct current, converts the direct current into an alternating current having a frequency F (and a voltage) according to a command from the control unit 31, and outputs it as an operating frequency. This output is given to the drive motor (compressor motor) of the compressor 2 as drive power,
Is controlled.

The light receiving section 32 receives infrared light transmitted from a remote control type operation device (hereinafter abbreviated as a remote controller) 33 and supplies a control signal superimposed on the infrared light to the control section 31. It is.

The controller 31 controls the entire air conditioner in accordance with a control command set by the remote controller 33 or the like. The controller 31 forms a cooling cycle, a dehumidification cycle, or a heating cycle, and performs a cooling operation, a dehumidification operation, or a heating operation. One of the operations is selectively executed, and the direction of the left / right and up / down wind direction changing plates 22 and 23 is controlled by controlling the wind direction changing plate motors 22M and 23M, and the air blown out from the air outlet 15 is controlled. Forms a short circuit airflow 34 (see FIG. 4) flowing into the front suction port 13, or controls the indoor fan 4 to operate at a low speed when the short circuit airflow 34 is formed.

The second speed control circuit 30 controls the rotation speed of the outdoor fan motor 8M (the amount of air blown by the outdoor fan 8) by controlling the supply of the power supply voltage to the outdoor fan motor 8M (for example, energizing phase control). The speed is set according to the instruction of No. 31. The first speed control circuit 29 controls the speed of the indoor fan motor 4M (the amount of air blown by the indoor fan 4) according to a command from the control unit 31 by controlling the supply of the power supply voltage to the indoor fan motor 4M (for example, energizing phase control). Set to speed.

The control section 31 comprises, for example, a microprocessor or the like, and includes an indoor fan control means 31a. The indoor fan control means 31a reduces the number of revolutions per unit time of the indoor fan 4, which is a blower of the main and auxiliary indoor heat exchangers 5 and 6, which functions as a condenser during the heating operation, before the operation. The control is performed to reduce the rotation speed of the compressor 2.

FIG. 1 is a flowchart of a processing program of the indoor fan control means 31a.
Indicates each step of the flowchart.

First, in step S1, when the indoor fan control means 31a receives an operation command signal for lowering (decreasing) the air flow of the indoor fan 4 from the remote controller 33 or the like, the indoor fan controller 31a executes step S1 before executing the control for lowering the air flow. At S2, control for reducing the operating frequency of the compressor 2 via the inverter circuit 28 is started.

Next, in step S3, it is repeatedly determined whether or not the operating frequency of the compressor 2 has decreased to the target operating frequency. That is, the indoor fan control means 31a previously associates each air volume tap corresponding to various rotation speeds of the indoor fan 4 with various operating frequencies of the compressor 2 to be operated at the air volume, and performs compression. It is determined whether or not the operating frequency of the compressor 2 has decreased to the target operating frequency of the compressor 2 corresponding to the air volume tap suitable for the operation command signal.

If Yes in step S3, that is, if the operating frequency of the compressor 2 has decreased to the target operating frequency, then in step S4, an air volume tap suitable for the operation command signal for reducing the air volume is selected. The amount of air blown from the indoor fan 4 is reduced.

According to the air volume control, the operating frequency of the compressor 2, that is, the rotation speed is reduced to lower the refrigerant discharge pressure of the compressor 2, and then the rotation speed of the indoor fan 4, that is, the blown air amount is reduced. Therefore, due to the decrease in the amount of air blow, the main and auxiliary indoor heat exchangers 5 and 6 acting as condensers during the heating operation
, Etc., can be prevented from excessively increasing.

For this reason, an excessive increase in the pressure of the main and auxiliary indoor heat exchangers 5 and 6 caused by an excessive increase in
Abnormal stop and high pressure release control can be reduced, and the reliability of the refrigeration cycle can be improved. Further, since it is not necessary to increase the pressure resistance of the refrigeration cycle more than before, the cost can be reduced.

The above-mentioned air conditioner has a heating capacity of 6.0 KW or higher and has a high output, and it is easy to increase the pressure. Therefore, such an air conditioner with a high output particularly effectively increases the pressure. Can be prevented.

FIG. 2 shows an air conditioner 1 configured as described above.
6 is a timing chart showing the relative relationship among the air flow rate of the indoor fan 4, the operating frequency of the compressor 2, and the high-pressure side pressure of the refrigeration cycle in comparison with the conventional example.

In FIG. 2, A is a first signal which does not lower the operating frequency of the compressor 2 even if the amount of air blown from the indoor fan 4 is reduced.
B shows a second conventional example in which the air volume is reduced and the operating frequency is reduced at the same time. Also, C
Indicates the case of the first embodiment of the present invention, and D indicates the case of the second embodiment of the present invention. In the second embodiment, the operating frequency of the compressor 2 is set in accordance with the amount of air to be reduced to reduce the operating frequency of the compressor 2,
This is an embodiment in which the air flow rate of the indoor fan 4 is reduced after the temperature is reduced to a midpoint below a preset maximum operating frequency of the compressor 2.

As shown in FIG. 2, in the first conventional example A, the operating frequency of the compressor 2, that is, the rotation speed is not reduced even at the time T1 even if the amount of air blown by the indoor fan 4 is reduced. The pressure on the high pressure side rises almost without decreasing.

Further, in the second conventional example B, at the time T1, the decrease in the amount of air blown from the indoor fan 4 and the decrease in the operating frequency of the compressor 2 are simultaneously performed, so that the effect of reducing the operating frequency of the compressor 2 is reduced. An excessive increase in the high-pressure side pressure occurs transiently until the pressure rises.

However, according to the first embodiment C of the present invention, the operation frequency of the compressor 2 is reduced at time T1, and then the amount of air blown by the indoor fan 4 is reduced at time T3. Immediately after the passage of time, the high-pressure side pressure can be immediately reduced to prevent an excessive rise.

Also, according to the second embodiment D of the present invention, the operating frequency of the compressor 2, that is, the rotation speed is reduced, and then the amount of air blown from the indoor fan 4 is reduced. Although not remarkable, the high-pressure side pressure is reduced from around the time T2 when the blown air amount is reduced, so that an excessive increase can be prevented. For this reason, it is possible to reduce the excessive rise of the pressure of the main and auxiliary indoor heat exchangers 5 and 6 due to the excessive rise of the high pressure side pressure, the abnormal stop for the compressor protection and the high pressure release control, and the reliability of the refrigeration cycle. Performance can be improved.

Further, even when a high-pressure refrigerant is used, it is not necessary to increase the pressure resistance of the refrigeration cycle, so that an increase in cost can be suppressed.

FIG. 6 is a flowchart of a control program of the control means 31b of the indoor fan according to the second embodiment of the present invention. In the drawing, S11 to S16 indicate each step of the flowchart.

The indoor fan control means 31b is replaced with or is added to the indoor fan control means 31a. The indoor fan control means 31b is provided for the main and auxiliary indoor heat exchangers 5, 6 which function as condensers during the heating operation. Indoor fan 4 to blow air
When the number of revolutions per unit time (hereinafter simply referred to as the number of revolutions) is decreased, the speed at which the number of revolutions of the indoor fan 4 is decreased is determined by the main and auxiliary indoor heat exchange temperature sensors 25 and 24. When the value is higher than the predetermined value, it is configured to be slower than when the value is lower than the predetermined value, thereby preventing an excessive increase in the high-pressure side pressure of the refrigeration cycle.

That is, as shown in FIG. 6, when the control program is started, the indoor fan control means 31b starts the heating operation in the first step S11. In the next step S12, the condensation temperature T of the main and auxiliary indoor heat exchangers 5, 6 functioning as a condenser during this heating operation.
c is read from the main and auxiliary indoor heat exchange temperature sensors 25 and 24. The temperature Tc of the condenser may be the temperature of one of the main and auxiliary indoor heat exchangers 5, 6, or both, or an average value of the temperatures of both.

Thereafter, in step S13, the indoor fan 4
It is determined whether or not an operation command signal for decreasing the number of rotations has been received. The number of rotations of the indoor fan 4 may be reduced, for example, when an operation command signal for reducing the amount of indoor air to be changed from a “strong wind” mode to a “weak wind” mode is received from a remote controller, or by an indoor controller. In some cases, the number of revolutions of the indoor fan 4 is automatically reduced.

If the result of step S13 is NO, the process returns to step S12 to continuously detect the condensation temperature Tc.
In the case of es, the process proceeds to S14. In S14, the main
It is determined whether or not the detected temperature Tc of the main and auxiliary indoor heat exchangers 5, 6 detected by the auxiliary indoor heat exchange temperature sensors 25, 24 is equal to or higher than a predetermined set temperature (predetermined value) Ts. That is, when the detected temperature Tc is lower than the set temperature Ts (Tc <Ts), it is determined that the pressures of the main and auxiliary indoor heat exchangers 5 and 6 are not relatively high.
In S15, the speed at which the number of revolutions of the indoor fan 4 is reduced is controlled via the first speed control circuit 29 to a relatively high speed, for example, -10 rpm / 0.2 sec. That is, the rotation speed of the indoor fan 4 is reduced by 10 rpm every 0.2 seconds.

On the other hand, if Yes in S14,
When the detected temperature Tc of the main and auxiliary indoor heat exchangers 5 and 6 is equal to or higher than a predetermined set temperature Ts (Tc> Ts), it is determined that the pressure of the main and auxiliary indoor heat exchangers 5 and 6 is in a high pressure state. In step S16, the speed at which the number of revolutions of the indoor fan 4 is reduced in step S16 is controlled via the first speed control circuit 29 to -10 rpm / 1 sec, which is, for example, about five times slower than the speed in step S15. I do. That is, the rotation speed of the indoor fan 4 is reduced by 10 rpm every second.

Therefore, when the detected temperature Tc of the main and auxiliary indoor heat exchangers 5 and 6 functioning as a condenser during the heating operation is higher than the predetermined value Ts, the pressure of the main and auxiliary indoor heat exchangers 5 and 6 is increased. Is determined to be in a high pressure state, and the speed at which the number of revolutions of the indoor fan 4 is reduced is reduced,
The decompression time of the main and auxiliary indoor heat exchangers 5 and 6 that are cooled and depressurized by the air blown from the indoor fan 4 can be lengthened. For this reason, it is possible to prevent or reduce a transient excessive increase in the high pressure side (discharge side) pressure of the refrigeration cycle.

FIG. 7 is a curve A showing the fluctuation of the discharge pressure (MPa) on the high pressure side immediately after the rotation speed is reduced by the indoor fan control means 13b. This curve A
Is that the transient rise in pressure on the high pressure side (discharge side) of the compressor can be effectively prevented and the pressure resistance reliability of the refrigeration cycle can be improved as compared with the conventional example shown by the curve B. Is shown. Note that, in the conventional example shown by the curve B, regardless of the temperatures of the main and auxiliary indoor heat exchangers 5 and 6 functioning as condensers, when the rotation speed of the indoor fan 4 is instructed, the indoor fan 4 FIG. 7 shows a state in which the high-pressure side pressure is transiently excessively increased.

FIG. 8 is a flowchart of a control program of the indoor fan control means 31c of the air conditioner according to the third embodiment of the present invention. In the drawing, S21 to S38 indicate each step of the flowchart.

The indoor fan control means 31c is replaced with the indoor fan control means 31a or added to the indoor fan control means 31a, 31b.
Detection value Tc of main and auxiliary indoor heat exchange temperature sensors 25 and 24
In addition, a characteristic feature is that a correction means for correcting by adding a correction value a (for example, 3 ° C.) for compensating a delay in the temperature detection operation by the temperature sensors 25 and 24 is provided.

That is, as shown in FIG. 8, when the control program is started, the indoor fan control means 31c first starts the heating operation in the first step S21. In the next step S22, the detected temperatures Tc of the main and auxiliary indoor heat exchangers 5 and 6 detected by the main and auxiliary indoor heat exchange temperature sensors 25 and 24 are read from the main and auxiliary indoor heat exchange temperature sensors 25 and 24. .

Thereafter, in a step S23, it is determined whether or not there is a command to decrease the rotation speed of the indoor fan 4 from a remote controller or the like.
If No, the control for reducing the rotational speed of the indoor fan 4 is not executed in step S24, and if Yes, the main and auxiliary indoor heat exchange temperature sensors 25 and 24 are executed in step S25.
To the detected temperature Tc, a correction value a for compensating for the delay of the detecting operation, for example, 3 ° C. is added. In the next step S26,
After counting the predetermined time by the timer, in step S27, the detected value Tca to which the correction value a is added is compared with a predetermined set temperature (predetermined value) Ts, and the detected value Tc
a is higher than the set temperature Ts, that is, Tc
When a> Ts is satisfied (Yes), the process proceeds to step S28, and when Tca> Ts is not satisfied (No), the process proceeds to step S29.

In step S29, it is determined that the pressures of the main and auxiliary indoor heat exchangers 25 and 24 are not in a high pressure state, and the speed at which the number of revolutions of the indoor fan 4 is reduced is set to a relatively high speed, for example, -10 rpm. /0.2 sec. On the other hand, when the correction detection value Tca is higher than the set value Ts,
In step S28, it is determined that the pressures of the main and auxiliary indoor heat exchangers 5 and 6 are in a high pressure state, and the speed at which the rotational speed of the indoor fan 4 is decreased is determined when the corrected detection value Tca is lower than the set value Ts. Speed, for example, -10
The speed is set to rpm / 1 sec, and set to a slowing-down speed, for example, about 1/5 lower than the speed of decreasing the indoor fan 4 in step S29. In the next step S30, the rotational speed of the indoor fan 4 is reduced by these set speeds. Execute control.

Thus, the main and auxiliary indoor heat exchangers 5, 6
When the value obtained by adding the correction value a to the detected value Tc is higher than a predetermined value, the rotation speed of the indoor fan 4 is not immediately reduced, but is gradually reduced.
It is possible to extend the decompression time of the main and auxiliary indoor heat exchangers 5, 6 which are cooled and depressurized by the air blow. For this reason, the high pressure side pressure of these main and auxiliary indoor heat exchangers 5, 6
As a result, it is possible to prevent or reduce the transient high rise of the high pressure side (discharge side) pressure of the refrigeration cycle.

Then, in the next step S31, it is determined whether or not the timer has finished counting the predetermined time. If not, the flow proceeds to step S32. Here, for example, it is determined whether or not there is an instruction to decrease the number of revolutions of the indoor fan 4 from a remote controller or the like. If Yes, the process returns to step S27 again. Stop the number reduction control.

On the other hand, when the timer ends in step S31, in step S33, the correction value a is cleared from the correction value Tca in step S27, and the detected value is returned to the detection value Tc. That is, while the timer measures the predetermined time, the initial detection value Tc detected by the main and auxiliary indoor heat exchange temperature sensors 25 and 24 may have a detection operation delay of these sensors 25 and 24. By adding the correction value a to the value Tc, the condition that the temperature becomes higher than the set temperature is expanded, and the condition of reducing the rotational speed reduction speed of the indoor fan 4 is expanded.

Then, in step S33, the correction detection value Tc
After the value a is returned to the original detection value, it is determined again in step S34 whether or not the rotation speed reduction command of the indoor fan 4 is continued from the remote controller or the like. If No, the detection value Tc in step S22 is detected again. Return to (Read) and repeat below.
On the other hand, if Yes in step S34, the original detection value Tc
Is compared with the set temperature Ts, and when No, that is, Tc>
If Ts is not established, the rotational speed reduction speed of the indoor fan 4 is set to a relatively high speed of, for example, -10 rpm / 0.2 sec in S36, while if Yes, that is, Tc>
When Ts is satisfied, the indoor fan 4 is higher than when No.
Is slow, for example, -10 rpm / 1 sec.
c, and in the next step S38, the indoor fan 4
Is performed, and thereafter, the process returns to step S22 to repeat the following steps.

Therefore, in this embodiment, the detection value Tc of the main and auxiliary indoor heat exchange temperature sensors 25 and 24 is compensated by the correction value a for compensating the delay of the temperature detection operation of the sensors 25 and 24. Both the temperature detection accuracy of the main and auxiliary indoor heat exchange temperature sensors 25 and 24 and the quickness of control can be improved.

In the fourth embodiment of the present invention, the control means 31 is provided with an outdoor fan control means 31x for controlling the rotation speed of the outdoor fan 8 during the cooling operation via the second speed control circuit 30. Thus, the present invention is characterized in that transient high rise of the high pressure side pressure of the refrigeration cycle is prevented.

That is, during the heating operation, the main and auxiliary indoor heat exchangers 5 and 6 function as condensers. However, during the cooling operation, the outdoor heat exchanger 9 functions as a condenser. By controlling the number of revolutions of the outdoor fan 8 for blowing heat to the exchanger 9 to promote heat exchange with the outside air for substantially the same reason and procedure as in the second or third embodiment, during the cooling operation, This also prevents the high pressure of the refrigeration cycle from rising excessively.

In other words, the control program by the outdoor fan control means 31x includes the heating operation, the indoor fan 4, the main and auxiliary indoor heat exchangers 5, 6, , Auxiliary indoor heat exchange temperature sensors 25, 24 and first speed control circuit 2
9 is replaced with a cooling operation, an outdoor fan 8, an outdoor heat exchanger 9, an outdoor heat exchange temperature sensor 9a, and a second speed control circuit 30, respectively.

That is, as shown in FIG. 6, when the outdoor fan control means 31x starts the control program, the outdoor fan control means 31x first starts the cooling operation in the first step S11. In the next step S12, the detected temperature (condensation temperature) T of the outdoor heat exchanger 9 functioning as a condenser during the cooling operation.
c is read from the outdoor heat exchange temperature sensor 9a.

Thereafter, in step S13, the outdoor fan 8
It is determined whether or not an operation command signal for decreasing the number of rotations has been received. As a case where the rotation speed of the outdoor fan 8 is reduced, for example, the rotation speed of the outdoor fan 8 may be automatically reduced by an outdoor controller.

If the result of step S13 is NO, the process returns to step S12, where the condensing temperature T is continuously detected.
In the case of es, the process proceeds to S14. In S14, it is determined whether or not the detected temperature Tc of the outdoor heat exchanger 9 detected by the outdoor heat exchange temperature sensor 9a is equal to or higher than a predetermined set temperature (predetermined value) Ts. T
When c is lower than the set temperature Ts (Tc <Ts), it is determined that the pressure of the outdoor heat exchanger 9 is not in a relatively high pressure state, and the speed at which the rotational speed of the outdoor fan 8 is reduced in S15. At a relatively high speed, for example, -10 rpm / 0.2
The control is performed via the second speed control circuit 30 in sec. That is, the rotation speed of the outdoor fan 4 is increased by 10 rpm every 0.2 seconds.
Decrease by m.

On the other hand, when Yes in S14, that is, when the detected temperature Tc of the outdoor heat exchanger 9 is equal to or higher than the predetermined temperature Ts (Tc> Ts), the pressure of the outdoor heat exchanger 9 is in a high pressure state. In step S16, the rotational speed of the outdoor fan 8 is decreased to reduce the speed, and the rotational speed (-c) when the detected temperature Tc of the outdoor heat exchanger 9 is lower than the predetermined value Ts (Tc <Ts).
10 rpm / 0.2 sec), for example, about 5 times slower, such as -10 rpm / 1 sec.
Via the speed control circuit 30.

That is, when the temperature of the outdoor heat exchanger 9 functioning as a condenser during the cooling operation is higher than the predetermined value Ts, the pressure of the outdoor heat exchanger 9 is in a high pressure state.
By reducing the speed at which the number of rotations of the outdoor fan 8 is reduced, the decompression time of the outdoor heat exchanger 9 that is cooled and depressurized by the air blown from the outdoor fan 8 can be increased, and as a result, the refrigeration cycle can be stopped. It is possible to prevent or reduce the transient high rise of the high pressure side pressure.

Therefore, the outdoor fan control means 31
By providing x and the indoor fan control means 31b in the control unit 31, it is possible to prevent or reduce an excessive increase in the high pressure side pressure of the refrigeration cycle during both cooling and heating operations.

Further, an outdoor fan control means 31 corresponding to the indoor fan control means 31c according to the third embodiment.
y may be provided in the control means 31. That is, the outdoor fan control means 31y uses the detection value Tc of the outdoor heat exchanger 9 detected by the outdoor heat exchange temperature sensor 9a to reduce the outdoor heat when the rotation speed of the outdoor fan 8 is reduced during the cooling operation. The correction is performed using a correction value a for compensating for the delay of the temperature detection operation of the intersecting temperature sensor 9a. -10 rpm / 0.2 sec)
Slower reduction speed (for example, -10 rpm / 1 sec)
Thus, the rotation speed of the outdoor fan 8 is controlled to decrease. According to this, it is possible to improve the temperature detection accuracy of the outdoor heat exchanger 9 by the outdoor heat exchange temperature sensor 9a during both the cooling and heating operations.

Therefore, it is possible to prevent or reduce an excessive increase in the high-pressure side pressure of the outdoor heat exchanger 9 and the main and auxiliary indoor heat exchangers 5 and 6 which function as a condenser during the cooling and heating operations. Overpressure on the high-pressure side can be prevented or reduced. The accuracy of the control for preventing the excessive increase of the high-pressure side pressure of the refrigeration cycle can also be improved.

[0094]

As described above, according to the first aspect of the present invention, when the number of revolutions per unit time (hereinafter simply referred to as the number of revolutions) of the condenser blower is reduced by the control means, the compression is first performed. Since the refrigerant discharge pressure of the compressor is reduced in advance by lowering the rotation speed of the compressor, it is possible to prevent a transient excessive increase in the high pressure side pressure of the refrigeration cycle and improve the reliability of the refrigeration cycle. Can be improved.

In the invention according to claim 7, when the rotation speed of the condenser blower is reduced, the rotation speed is not reduced immediately,
When the temperature of the condenser at that time is higher than a predetermined value, the rotation speed is gradually decreased at a lower speed than when the temperature of the condenser is lower than the predetermined value. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a flowchart of a processing program of an indoor fan control unit of an air conditioner according to a first embodiment of the present invention.

FIG. 2 is a timing chart showing the operation and effect of the first and second embodiments of the present invention in comparison with a conventional example.

FIG. 3 is a refrigeration cycle diagram of the air conditioner according to the first embodiment of the present invention.

FIG. 4 is a side sectional view of an example of the indoor unit shown in FIG. 3;

FIG. 5 is a schematic diagram showing a refrigeration cycle and a control system of the air conditioner according to the first embodiment of the present invention.

FIG. 6 is a flowchart of a control program of an indoor fan control unit of the air conditioner according to the second embodiment of the present invention.

FIG. 7 is a graph showing a change in discharge pressure (high-pressure side pressure) of a refrigeration cycle immediately after a decrease in the amount of air blown by an indoor fan of an air conditioner according to a second embodiment of the present invention, in comparison with a conventional example.

FIG. 8 is a flowchart of a control program of an indoor fan control unit of an air conditioner according to a third embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 2 compressor 4 indoor fan 5 main indoor heat exchanger 6 auxiliary indoor heat exchanger 7 electric expansion valve (decompressor) 8 outdoor fan 9 outdoor heat exchanger 9a outdoor heat exchange temperature sensor 31a, 31b, 31c indoor fan control means 31x , 31y Outdoor fan control means

Continued on the front page (72) Inventor Toru Kubo 336 Tatehara, Fuji-shi, Shizuoka Prefecture Inside Fuji Plant, Toshiba Corporation (72) Inventor Hiroyuki Arakawa 336 Tatehara, Fuji City, Shizuoka Prefecture Inside Fuji Plant, Toshiba Corporation (72) Inventor Ota Kishi 336 Tatehara, Fuji City, Shizuoka Prefecture Toshiba Corporation Fuji Plant

Claims (10)

[Claims] 1. A refrigeration cycle in which a compressor, a condenser, a decompressor, and an evaporator, whose rotation speed is controllable, are sequentially communicated to circulate a refrigerant, a condenser blower, whose rotation speed is controllable, which blows the condenser. In the air conditioner having, when reducing the number of rotations per unit time of the condenser blower, a control means for reducing the number of rotations per unit time of the compressor is provided before that. Air conditioner. 2. The control means reduces the operating frequency of the compressor to an operating frequency set in advance corresponding to the amount of air blown by the condenser blower which is to be reduced, or sets the operating frequency to a maximum value. The air conditioner according to claim 1, wherein the air flow of the condenser blower is reduced after the frequency is reduced to a frequency lower than or equal to an intermediate frequency with the operating frequency. 3. The air conditioner according to claim 1, wherein the condenser is an indoor heat exchanger during a heating operation. 4. The refrigerant has a saturation pressure at 50 ° C. of 2500K.
The air conditioner according to any one of claims 1 to 3, wherein the refrigerant is a high-pressure refrigerant of Pa or more. 5. The air conditioner according to claim 4, wherein the high-pressure refrigerant is a mixed refrigerant containing at least R32 (difluoromethane). 6. The air conditioner according to claim 1, wherein the heating capacity is equal to or more than 6.0 KW. 7. A refrigeration cycle in which a compressor whose number of rotations can be controlled, an outdoor heat exchanger, a decompressor, and an indoor heat exchanger are sequentially communicated to circulate a refrigerant, and a number of rotations that can be blown to the indoor heat exchanger can be controlled. In the air conditioner having an indoor fan, an indoor heat exchange temperature sensor that detects the temperature of the indoor heat exchanger during a heating operation, and the number of rotations of the indoor fan when the number of rotations per unit time is reduced, An air conditioner comprising: control means for reducing the speed at which the temperature is reduced when the value detected by the indoor heat exchange temperature sensor is higher than a predetermined value than when the value is low. 8. A correction means for correcting a detection value detected by the indoor heat exchange temperature sensor and supplied to the control means with a correction value for compensating for a delay in a temperature detection operation by the indoor heat exchange temperature sensor. 8. The method according to claim 7, wherein
The air conditioner as described. 9. A refrigeration cycle in which a compressor, an outdoor heat exchanger, a decompressor, and an indoor heat exchanger whose flow rate can be freely controlled are sequentially communicated with each other to circulate a refrigerant, and a flow rate controllable to blow air to the outdoor heat exchanger. An outdoor fan having an outdoor heat exchange temperature sensor for detecting the temperature of the outdoor heat exchanger during a cooling operation, and the number of rotations of the outdoor fan when the number of rotations per unit time is reduced. An air conditioner comprising: control means for decreasing the speed at which the temperature is reduced when the value detected by the outdoor heat exchange temperature sensor is higher than a predetermined value than when the value is low. 10. Detected by an outdoor heat exchange temperature sensor,
10. The air conditioner according to claim 9, further comprising a correction unit that corrects a detection value given to the control unit with a correction value that compensates for a delay in a temperature detection operation by the outdoor heat exchange temperature sensor.