JPH11281126A - Method of control valve operation of air conditioner and air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To completely open a control valve from a closed state without increasing cost of the control valve. SOLUTION: In a method for operating a motor operated expansion valve of an air conditioner 10 comprising an outdoor unit 11 provided with compressors 16 through 16C and an outdoor heat exchanger 19, and a plurality of indoor units 12A, 12B,... and the like provided with an indoor heat exchanger 21 and a motor operated expansion valve 22 for controlling the flow rate of refrigerant, under a condition wherein the operation capacity of the compressors 16A through 16C is caused to lower so as to reduce the pressure difference of the refrigerant acting on the motor operated expansion valve 22 during cooling operation of the air conditioner 10, the motor operated expansion valve 22 in a fully closed state in part of the indoor unit is opened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for operating a control valve of an air conditioner and an air conditioner for implementing the method.

[0002]

2. Description of the Related Art A multi-type air conditioner includes an outdoor unit having a compressor and an outdoor heat exchanger, and a plurality of indoor units having an indoor heat exchanger and an electric expansion valve capable of controlling a flow rate of a refrigerant. The compressor, the electric expansion valve, and the like are controlled by the control device to perform cooling or heating in each of the plurality of indoor units.

[0003]

During the cooling operation of the air conditioner, the operation of some indoor units may be stopped. In this case, the electric expansion valve of the indoor unit is connected to the indoor unit. It is operated in the fully closed state so that the refrigerant does not flow into the indoor heat exchanger of the machine. At this time, since the other indoor unit is in operation, the pressure difference between the discharge side refrigerant pressure and the suction side refrigerant pressure in the compressor of the outdoor unit is slightly lower than the pressure difference between the discharge side refrigerant pressure and the suction side refrigerant pressure. Is working.

[0004] Generally, an operating limit pressure difference (MOP) exists in an electric expansion valve, and if a pressure difference greater than the operating limit pressure difference acts on the electric expansion valve, the opening and closing operation of the electric expansion valve becomes impossible. Would.

The pressure difference acting on the electric expansion valve is small in the case of a single refrigerant such as R22 or an azeotropic refrigerant,
In the case of a non-azeotropic mixed refrigerant such as that described above, it tends to increase.
Therefore, in the case of a single refrigerant or an azeotropic refrigerant, an electric expansion valve having an operation limit pressure difference of about 23 to 25 kg / cm 2 is adopted, and in the case of a non-azeotropic refrigerant mixture, an operation limit pressure difference of about 27 kg / cm 2 is used. / Cm2 is required to be used.

However, in the case of an air conditioner using a non-azeotropic mixed refrigerant, the use of an electric expansion valve that meets the above-mentioned demands leads to an increase in cost.

[0007] Further, in an air conditioner using a non-azeotropic refrigerant mixture, even if an inexpensive electric expansion valve having an operating limit pressure of about 23 to 25 kg / cm2 for a single refrigerant or an azeotropic refrigerant is adopted, In most usage situations no inconveniences occur, only in very special circumstances.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above circumstances, and provides an air conditioner that can reliably open a control valve from a fully closed state without increasing the cost of the control valve. An object of the present invention is to provide a control valve operating method of an apparatus and an air conditioner.

[0009]

According to the first aspect of the present invention,
A control valve for an air conditioner including an outdoor unit having a compressor and an outdoor heat exchanger, and an indoor heat exchanger and a plurality of indoor units having a control valve capable of controlling a flow rate of a refrigerant. In the operation method, at the time of the cooling operation of the air conditioner, the operation capacity of the compressor is temporarily reduced so as to reduce the pressure difference of the refrigerant acting on the control valve, and then a part of the indoor units is fully closed. The control valve in the state is opened.

According to a second aspect of the present invention, in the first aspect of the present invention, a signal for opening the fully closed control valve in some of the indoor units is transmitted when the operating capacity of the compressor is reduced. This is performed when the control valve detects that the control valve is in the fully closed state in the closed state.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the opening operation of the fully closed control valve in some of the indoor units reduces the operating capacity of the compressor. In this state, first, the positioning control is performed, then the normal opening operation control is performed, and thereafter, the operating capability of the compressor is restored.

According to a fourth aspect of the present invention, there is provided the control valve according to any one of the first to third aspects, wherein the control valve is in a fully closed state in some indoor units in a state in which the operating capacity of the compressor is reduced. Is controlled to open, and thereafter, the operating state of the control valve is detected.

According to a fifth aspect of the present invention, in the first aspect of the present invention, a signal is transmitted to open the control valve in the partially closed state in some of the indoor units. Then, the control valve detects that the control valve is in the fully closed state, and subsequently reduces the operating capacity of the compressor to detect the operation state of the control valve.

According to a sixth aspect of the present invention, there is provided an outdoor unit having the compressor and the outdoor heat exchanger, an indoor heat exchanger, and a plurality of indoor units having a control valve capable of controlling the flow rate of the refrigerant. In the air conditioner, wherein the compressor and the control valve are controlled by a control device, the control device reduces a pressure difference of the refrigerant acting on the control valve during a cooling operation of the air conditioner. In a state where the operation capacity of the compressor is temporarily reduced, the control valve in a fully closed state in some of the indoor units is opened.

The invention according to claim 1, 2, 3 or 6 has the following effects.

During the cooling operation of an air conditioner having a plurality of indoor units, some of the indoor units may stop operating and other indoor units may continue to operate. A pressure difference slightly lower than the pressure difference between the discharge-side refrigerant pressure and the suction-side refrigerant pressure of the compressor of the outdoor unit acts on the control valve in the fully closed state of the indoor unit. In addition, a control valve generally has an operating limit pressure difference. If a pressure difference greater than the operating limit pressure difference acts on the control valve, the control valve in the fully closed state cannot be opened.

In the present invention, since the operating capacity of the compressor is reduced to reduce the pressure difference acting on the control valve and the fully closed control valve is opened, the fully closed control valve is opened. Even if the pressure difference acting on the control valve is equal to or greater than the operation limit pressure difference, the pressure difference can be reduced to the operation limit pressure difference or less by reducing the operating capacity of the compressor. Opening operation can be ensured.

Further, since the operating capacity of the compressor is reduced to reduce the pressure difference acting on the control valve and the on-off valve in the fully closed state is opened, a high performance with a high operating limit pressure difference is provided. In addition, since it is not necessary to employ a high-priced control valve, an increase in cost can be avoided.

The invention described in claim 4 has the following operation.

When the operating capacity of the compressor is reduced, control is performed to open the fully closed control valve, and thereafter, the operating state of the control valve is detected. Therefore, when the control valve does not open even though the pressure difference acting on the control valve in the fully closed state has been changed to be equal to or less than the operation limit pressure difference, the control valve may not operate due to the excessive pressure difference. Can be determined not to be a malfunction of the control valve but to a failure of the control valve itself, and a failure of the control valve can be detected.

The invention described in claim 5 has the following operation.

In a state where a signal for opening the control valve in the fully closed state is transmitted, it is detected that the control valve is in a fully closed state. Since the operation state of the valve is detected, the operating capacity of the compressor is reduced, and the pressure difference acting on the control valve in the fully closed state is changed to the operation limit pressure difference or less. When the opening operation is not performed, it can be determined that the control valve is not a malfunction due to an excessive pressure difference but a malfunction of the control valve itself. In addition, since this determination can be made before the opening control of the control valve, in case of failure of the control valve itself, maintenance such as repair or replacement of the control valve can be quickly performed.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram showing an air conditioner that implements a method of operating an electric expansion valve of an air conditioner, which is an embodiment of a method of operating a control valve of an air conditioner according to the present invention.

As shown in FIG. 1, the air conditioner 10
Comprises an outdoor unit 11, a plurality of indoor units 12A, 12B... And a control device 13, and the outdoor refrigerant pipe 1 of the outdoor unit 11
Are connected to the indoor refrigerant pipes 15 of the indoor units 12A, 12B,... To form a refrigerant circuit through which the non-azeotropic mixed refrigerant flows.

The outdoor unit 11 is installed outdoors, and variable capacity compressors 16A, 16B, 16C are arranged in parallel in the outdoor refrigerant pipe 14, and these compressors 16A, 16B, 16
An accumulator 17 is provided on the suction side of C, and a four-way valve 1 is provided on the discharge side.
8 is connected via an outdoor refrigerant pipe 14, and an outdoor heat exchanger 19 and an electric expansion valve 24 are connected to the four-way valve 18 via the outdoor refrigerant pipe 14. An outdoor fan 20 that blows air toward the outdoor heat exchanger 19 </ b> H is arranged adjacent to the outdoor heat exchanger 19.

On the other hand, the indoor units 12A, 12B,... Are installed indoors, respectively. An electric expansion valve 22 as a control valve is provided and configured. The indoor heat exchanger 21
Has an indoor fan 23 that blows air to the indoor heat exchanger 21.
Are arranged adjacent to each other.

The control device 13 controls the operation of the outdoor unit 11 and the indoor units 12A, 12B..., And specifically, the compressors 16A to 16C, the four-way valve 18, the outdoor fan 20, It controls the electric expansion valve 24, the electric expansion valve 22 in the indoor units 12A, 12B,... And the indoor fan 23, respectively.

When the four-way valve 18 is switched by the control device 13, the air conditioner 10 is set to the cooling operation or the heating operation. That is, the control device 13 controls the four-way valve 1
8 is switched to the cooling side, the refrigerant flows as shown by the solid line arrow, and the outdoor heat exchanger 19 is connected to the condenser and the indoor heat exchanger 2
1 becomes an evaporator and enters a cooling operation state, and each indoor unit 12
A, 12B... Indoor heat exchangers 21 cool the room. When the control device 13 switches the four-way valve 18 to the heating side, the refrigerant flows as indicated by the dashed arrow and the indoor heat exchanger 21
.. Become a condenser, and the outdoor heat exchanger 19 becomes an evaporator to enter a heating operation state, and the indoor heat exchangers 21 of the indoor units 12A, 12B.

The control device 13 also controls the electric expansion valve 22 in the indoor unit 12A according to the air conditioning load of the indoor unit 12A.
Of the indoor fan 23 in the indoor unit 12A.
And the opening degree of the electric expansion valve 22 in the indoor unit 12B is adjusted according to the air conditioning load of the indoor unit 12B, and the indoor fan 23 in the indoor unit 12B is controlled. The control device 13 similarly controls other indoor units.

Now, in the above-described air conditioner 10, an indoor temperature sensor 25 such as a thermistor is installed in each indoor refrigerant pipe 15 of the indoor units 12A, 12B,. The indoor temperature sensor 25 is installed in the indoor refrigerant pipe 15 between the indoor heat exchanger 21 and the electric expansion valve 22,
During the cooling operation of the air conditioner 10, the indoor heat exchanger 21 from the outdoor heat exchanger 19 of the outdoor unit 11 via the electric expansion valve 22
The temperature of the refrigerant flowing to the refrigerant is detected. Similarly, an outdoor temperature sensor 26 such as a thermistor is installed on a coil tube (not shown) in the outdoor heat exchanger 19 of the outdoor unit 11. This outdoor temperature sensor 26 is connected to the outdoor heat exchanger 19.
The temperature of the refrigerant flowing through the coil tube is detected, and the pressure of the refrigerant discharged from the compressors 16A to 16C is indirectly detected.

In the air conditioner 10, the operation of some of the indoor units (eg, 12A) among the indoor units 12A, 12B,... Is stopped during the cooling operation, and the other indoor units (eg, 12B,. ) May be in operation. In this case, for example, the indoor unit 12A in a stopped state
The electric expansion valve 22 is fully closed so that the refrigerant from the outdoor unit 11 does not flow into the indoor heat exchanger 21 of the indoor unit 12A. At this time, since the other indoor units 12B,... Are in the cooling operation state, the electric expansion valve 22 in the fully closed state is
A pressure slightly lower than the discharge-side refrigerant pressure of the compressors 16A to 16C and a pressure slightly higher than the suction-side refrigerant pressure of the compressors 16A to 16C act, that is, a difference between these pressures (the pressures of the compressors 16A to 16C). (A pressure difference slightly lower than the pressure difference between the refrigerant pressure on the discharge side and the suction side).

The electric expansion valves 22 of the indoor units 12A, 12B,... Have an operating limit pressure difference (MOP), and when the pressure difference acting on the electric expansion valves 22 is equal to or larger than the operating limit pressure difference, The expansion valve 22 cannot operate. In the present embodiment, the electric expansion valve 2 of the indoor units 12A, 12B,.
The working limit pressure difference of 2 is 23 to 25 km / cm2.

During the cooling operation of the air conditioner 10, if the pressure difference acting on the electric expansion valve 22 in the fully closed state of the indoor unit 12A in the stopped state becomes equal to or larger than the operating limit pressure difference of the electric expansion valve 22, Even if an open operation signal (pulse signal) is output to the electric expansion valve 22 to operate the machine 12A (thermo-ON), the electric expansion valve 22 may not be opened. At this time, the control device 13 executes the following procedures (1) to (6) to open the electric expansion valve 22.

(1) First, the control device 13 outputs a thermo-ON signal for operating the indoor unit 12A in a stopped state, that is, a signal for opening the electric expansion valve 22 of the indoor unit 12A for a predetermined time. After the lapse, this indoor unit 1
The following judgment is made based on the refrigerant temperature detected by the indoor temperature sensor 25 of 2A. That is, the control device 13 determines whether the temperature detected by the indoor temperature sensor 25 after the lapse of the predetermined time has not become equal to or lower than the predetermined temperature A or the temperature detected by the indoor temperature sensor 25 after the lapse of the predetermined time has reached the thermostat. If the temperature does not change more than a certain width compared to when the ON signal is not output, the indoor unit 12
It is determined that the electric expansion valve 22 of A is not yet opened and is in the fully closed state.

(2) After judging the above-mentioned poor opening operation of the electric expansion valve 22 of the indoor unit 12A in the stopped state, the control device 13 lowers the operating capacity of the compressors 16A to 16C, and The pressure acting on the 12A electric expansion valve 22 is changed so as to be equal to or less than the operation limit pressure difference of the electric expansion valve 22. At this time, the control device 13
The operation of A to 16C may be stopped.

(3) Next, the controller 13 controls the compressor 16
In a state in which the operation capacity of A to 16C is reduced, the positioning control of the electric expansion valve 22 of the indoor unit 12A is performed, and after the positioning control is completed, the normal opening operation control is performed, and the above-described fully closed state is performed. The electric expansion valve 22 in the state is opened.

(4) Thereafter, the control device 13 sets the compressor 1
When the refrigerant temperature detected by the indoor temperature sensor 25 of the indoor unit 12A is not lower than or equal to the predetermined temperature A in a state where the operation capacity of the indoor units 6A to 16C is reduced, or
If the temperature change does not exceed a certain width compared to when the indoor unit 12A is stopped, the electric expansion valve 22 of the indoor unit 12A causes the pressure difference acting on the electric expansion valve 22 to become the operating limit pressure. It is determined that the failure is not the opening operation failure due to the difference or more, but the opening operation failure due to the failure of the electric expansion valve 22 itself, and outputs an alarm.

(5) Indoor temperature sensor 25 of indoor unit 12A
After the determination of the procedure (4) based on the refrigerant temperature detected by the control unit 13, the control device 13 returns the operating capabilities of the compressors 16A to 16C to the normal operating capabilities.

Note that the control device 13 may execute the following procedure (6) after the procedure (1).

(6) Under the condition that the signal for opening the electric expansion valve 22 of the indoor unit 12A in the stopped state is output, the control device 13 executes the compressors 16A to 16A in the same manner as in the procedure (2). Decreases 16C operating capacity. Thereafter, based on the refrigerant temperature detected by the outdoor temperature sensor 26 of the outdoor unit 11, if the refrigerant temperature is equal to or lower than the predetermined temperature B, the control device 13 determines a pressure difference acting on the electric expansion valve 22 of the indoor unit 12A. Can be determined to be equal to or lower than the operating limit pressure difference of the electric expansion valve 22, and even in this state, the refrigerant temperature detected by the indoor temperature sensor 25 of the indoor unit 12A becomes equal to or lower than the predetermined temperature A described above. If not, or
If the temperature change does not exceed a certain width as compared with when the indoor unit 12A is stopped, the electric expansion valve 22 of the indoor unit 12A causes the pressure difference acting on the electric expansion valve 22 to reach the operation limit. It is determined that the failure is not the opening operation failure due to the pressure difference or more but the opening operation failure due to the failure of the electric expansion valve 22 itself. When it is determined that the electric expansion valve 22 is out of order, the control device 13 does not execute the position control and the normal opening operation control (procedure (3)) of the electric expansion valve 22 of the indoor unit 12A thereafter. Compressors 16A-16C
Of the indoor unit 12A and outputs an alarm indicating that the electric expansion valve 22 of the indoor unit 12A is out of order.

As described above, according to the above-described embodiment, the following effects are obtained.

During the cooling operation of the air conditioner 10 having a plurality of outdoor units 11, some of the indoor units (for example, 12A)
May stop operating, and another indoor unit (for example, 12B,...) May continue to operate. In this case, in order to operate the indoor unit 12A, the electric expansion valve 22 of the indoor unit 12A is operated. Compressor 16 to reduce the pressure differential acting on
Since the operating capacity of A to 16C is reduced to open the fully-closed electric expansion valve 22, the pressure difference acting on the fully-closed electric expansion valve 22 is equal to or greater than the operating limit pressure difference at this place. Even so, the pressure difference can be reduced to the operating limit pressure difference or less by lowering the operating capacity of the compressors 16A to 16C, so that the opening operation of the fully closed electric expansion valve 22 can be ensured. .

Since the operating capacity of the compressors 16A to 16C is reduced to reduce the pressure difference acting on the electric expansion valve 22 and the electric expansion valve 22 in the fully closed state is opened, the operating limit pressure is set. Since it is not necessary to employ a high-performance and high-priced electric expansion valve 22 having a high difference, an increase in cost can be avoided.

In a state where the operating capacity of the compressors 16A to 16C is reduced, the fully-closed electric expansion valve 22 is controlled to be opened, and then the operation state of the electric expansion valve 22 is controlled by the indoor temperature sensor 25. Although the operating capacity of the compressors 16 </ b> A to 16 </ b> C is reduced and the pressure difference acting on the electric expansion valve 22 in the fully closed state is changed to be equal to or less than the operation limit pressure difference, the electric When the expansion valve 22 does not open, it can be determined that the electric expansion valve 22 is not a malfunction due to an excessive pressure difference but is a failure of the electric expansion valve 22 itself. Can be detected.

In a state in which the signal for opening the fully-closed electric expansion valve 22 is transmitted, it is detected that the electric expansion valve 22 is in the fully-closed state.
Since the operation state of the electric expansion valve 22 is detected by using the indoor temperature sensor 25 by reducing the operation capacity of the electric expansion valve 16C, the operation capacity of the compressors 16A to 16C is reduced, and the electric expansion valve in the fully closed state is reduced. 22 has been changed to be equal to or less than the operating limit pressure difference.
When the electric expansion valve 22 is not opened, the electric expansion valve 22 is not in a malfunction due to an excessive pressure difference.
It can be determined that the failure is itself. Moreover, this judgment,
Since the operation can be performed before the opening operation control of the electric expansion valve 22 including the positioning control, in the case of a failure of the electric expansion valve 22 itself, maintenance such as repair or replacement of the electric expansion valve 22 can be quickly performed.

Although the present invention has been described based on an embodiment, the present invention is not limited to this.

[0048]

As described above, according to the method for operating the control valve of the air conditioner and the air conditioner according to the present invention, the pressure difference of the refrigerant acting on the control valve of the indoor unit during the cooling operation of the air conditioner. With the operating capacity of the compressor of the outdoor unit lowered to reduce the pressure, the control valve in the fully closed state of some indoor units is opened, so a control valve with a high operating limit pressure difference is adopted. The control valve can be reliably opened from the fully closed state without increasing the cost.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an air conditioner that implements a method for operating an electric expansion valve of an air conditioner, which is one embodiment of a method for operating a control valve of an air conditioner according to the present invention.

[Explanation of symbols]

 Reference Signs List 10 air conditioner 11 outdoor unit 12A, 12B indoor unit 13 controller 16A, 16B, 16C compressor 19 outdoor heat exchanger 21 indoor heat exchanger 22 electric expansion valve 25 indoor temperature sensor 26 outdoor temperature sensor

Claims (6)

[Claims] 1. An air having an outdoor unit having a compressor and an outdoor heat exchanger, an indoor heat exchanger, and a plurality of indoor units having a control valve capable of controlling a flow rate of a refrigerant. In a method of operating a control valve of a harmony device, in a cooling operation of the air-conditioning device, the operation capacity of the compressor is reduced in order to reduce a pressure difference of a refrigerant acting on the control valve, and a part of the indoor space is reduced. A method of operating a control valve of an air conditioner, comprising: opening the control valve in a fully closed state in the air conditioner. 2. The decrease in the operating capacity of the compressor is caused by the fact that the control valve is in a fully closed state under a state in which a signal for opening a fully closed control valve in some indoor units is transmitted. 2. The method according to claim 1, wherein the step is carried out when a condition is detected.
3. The method for operating a control valve of an air conditioner according to claim 1. 3. The opening operation of the control valve in the fully-closed state in some of the indoor units described above is performed by first performing positioning control with the operating capability of the compressor being reduced, and then performing the normal opening operation. The method according to claim 1 or 2, wherein the control is performed, and thereafter, the operating capability of the compressor is restored. 4. In a state where the operating capacity of the compressor is reduced, control is performed to open a fully closed control valve in some indoor units, and thereafter, the operating state of the control valve is detected. The method for operating a control valve of an air-conditioning apparatus according to any one of claims 1 to 3, wherein: 5. In a state where a signal for opening a fully closed control valve in some of the indoor units is transmitted, it is detected that the control valve is in a fully closed state. The method for operating a control valve of an air-conditioning apparatus according to any one of claims 1 to 4, wherein the operating state of the control valve is detected by reducing the operating capacity of the control valve. 6. An outdoor unit having a compressor and an outdoor heat exchanger, an indoor heat exchanger, and a plurality of indoor units having a control valve capable of controlling a flow rate of a refrigerant, wherein the compressor and In the air conditioner in which the control valve is controlled by a control device, the control device sets the operating capacity of the compressor to reduce a pressure difference of the refrigerant acting on the control valve during a cooling operation of the air conditioner. An air conditioner characterized by opening the control valve in a fully closed state in some of the indoor units in a lowered state.