JPH0650589A - Operation control in air conditioner - Google Patents

Abstract

PURPOSE:To prevent a refrigerant from being supplied and circulated to an indoor unit not in heating operation, by determining a refrigerant shortage in an outdoor heat exchanger based on an opening degree of an outdoor expansion valve and a difference of temperature between refrigerant inlet and outlet of the outdoor heat exchanger. CONSTITUTION:A refrigerant temperature T3 flowing into an outdoor heat exchanger 7 measured by a temperature sensor S3, a refrigerant temperature T4 flowing out of the outdoor heat exchanger 7 measured by another temperaure sensor S4 and an opening degree of an outdoor expansion valve 6 are inputted into a controller 10. In this instance, during a heating operation with the opening degree of the outdoor expansion valve 6 at 300 steps, for example, if a temperature difference between the refrigerant temperatures T4 and T3 is 6 deg.C, it is determined that the refrigerant is not short. On the other hand, the temperature difference is 8 deg.C, judging that the temperature difference is increased by an abnormal rising of the refrigerant temperature T4 on the outlet side with the opening degree at 300 steps, a refrigerant shortage is determined. By this, it is basically prevented that refrigerant vapor is supplied to the indoor unit not in operation, and therefore, air conditioning efficiency in a room whose indoor unit is not in operation can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control method for an air conditioner having an indoor unit.

[0002]

2. Description of the Related Art As an air conditioner of this type, for example, an outdoor unit having a compressor and an outdoor heat exchanger and a plurality of indoor heat exchangers disclosed in JP-A-3-50466 are disclosed. A cooling / heating device having a structure in which an indoor unit is connected by piping between units is well known.

In the conventional device, the control of the flow of the refrigerant to each of the plurality of indoor units is performed by, for example, heating operation so that the temperature of the indoor heat exchanger of each indoor unit becomes equal by a temperature sensor installed in the indoor heat exchanger. For example, the motor-operated valve of the indoor unit whose heat exchanger temperature is high is controlled by narrowing the opening, and the motor-operated valve of the indoor unit whose temperature is low is controlled by opening the opening.

For an indoor unit that does not perform the heating operation, it is desirable to completely close the indoor motorized valve to stop the supply of the refrigerant from the viewpoint of thermal efficiency, but if the circulation of the refrigerant is completely stopped, the compressor is stopped. Refrigerant vapor that is compressed to high temperature / high pressure is also cooled and condensed, and it accumulates in the indoor heat exchanger, etc., and the refrigerant to be used for heating operation becomes insufficient, resulting in insufficient heating capacity. Even for the indoor unit that is not operated for the purpose, the indoor motor-operated valve is slightly opened so that a small amount of refrigerant constantly circulates.

[0005]

However, supplying and circulating a small amount of refrigerant to an indoor unit that is not in heating operation not only lowers the thermal efficiency and deteriorates the coefficient of performance, but it also The heating capacity of the indoor unit decreases. In addition, the temperature of the room in which the indoor unit is stopped rises. Then, there is a problem that this increase in room temperature occurs remarkably during the blow operation, and it has been a problem to solve these problems.

[0006]

As a concrete means for solving the above-mentioned problems of the prior art, the present invention provides a refrigerant compressor, an indoor heat exchanger, an indoor electric valve, an outdoor expansion valve, and an outdoor heat exchanger. -In an air conditioner in which a heating circuit is formed by sequentially connecting accumulators and the like, it is possible to determine the shortage of refrigerant in the outdoor heat exchanger from the difference between the opening of the outdoor expansion valve and the refrigerant inlet / outlet temperature difference of the outdoor heat exchanger. An operation control method in a characteristic air conditioner,

In an air conditioner in which a heating circuit is formed by sequentially connecting a refrigerant compressor, an indoor heat exchanger, an indoor electric valve, an outdoor expansion valve, an outdoor heat exchanger, an accumulator, etc., the air conditioner is an indoor unit. If the temperature difference between the heat exchanger temperature and the indoor temperature of the indoor unit that has a plurality of indoor units provided with a heat exchanger and a blower fan and is not in heating operation is less than or equal to a first predetermined temperature, then When the blower fan of the unit is stopped and the indoor electrically operated valve of the unit is opened to a predetermined opening, and when the temperature difference becomes equal to or higher than a second predetermined temperature higher than the first predetermined temperature, the indoor electrically operated valve of the unit is turned on. By providing an operation control method in an air conditioner characterized by closing the blower fan of the unit and returning the blower fan to the original setting state when the unit is closed.

[0008]

[Operation] If a sufficient amount of refrigerant circulates in the heating circuit,
The temperature difference of the refrigerant at the inlet / outlet of the outdoor expansion valve falls within a predetermined range, but if the amount of circulating refrigerant is insufficient,
Since the refrigerant temperature on the outlet side rises and the temperature difference spreads beyond a predetermined range, the refrigerant temperature at the outlet and the inlet of the outdoor expansion valve is measured, and this temperature difference and the opening degree of the outdoor expansion valve are measured. By comparison, it is possible to detect whether or not a large amount of liquid refrigerant has accumulated in the indoor heat exchanger that is not performing the heating operation, and the heating capacity is reduced.

The temperature difference between the temperature of the heat exchanger of the indoor unit in which the heating operation is stopped and the temperature of the indoor air is measured, and when this is lower than the first predetermined temperature (for example, about 3 to 10 ° C.), It shows that the refrigerant vapor that has been compressed by the compressor and has become a high temperature and high pressure state has already been cooled and has become liquid refrigerant and has accumulated in the indoor heat exchanger, etc.

If the blower fan of the unit is used for blowing or the like, it is stopped to stop the heat exchange, and at the same time, the indoor electric valve of the unit is slightly opened to a predetermined opening degree for circulation. The retained liquid refrigerant is promptly recovered.

When the liquid refrigerant is recovered and the refrigerant vapor in a high temperature / high pressure state is supplied from the compressor, the second temperature difference is set higher than the first predetermined temperature (for example, about 5 ° C.). Since the temperature exceeds the predetermined temperature, the indoor motor-operated valve of the unit is closed to stop the supply and circulation of the refrigerant to the stopped indoor unit, and at the same time, the blower fan of the unit is returned to the original setting state to perform the blowing operation. It will be restarted.

[0012]

EXAMPLE FIG. 3 shows an outdoor unit U0 and an indoor unit U.
1 shows a system example of an air conditioner capable of cooling and heating, which is configured by connecting 1 and U2 in parallel. In the figure, 1 is a compressor driven by a gasoline engine, a gas engine, an electric motor, etc., and 2 is cold / warm switching. For four-way valve, 3 for indoor heat exchanger, 4
Is an indoor electric valve that acts as an expander during cooling and acts as a refrigerant shunt control valve for each indoor unit during heating (hereinafter,
5 is a receiver tank, 6 is an outdoor expansion valve, 7 is an outdoor heat exchanger, 8 is an accumulator,
Each of them is a conventionally well-known device, and is sequentially connected via a refrigerant pipe L to form a cooling circuit A shown by a solid line and a heating circuit B shown by a broken line.

In addition to the indoor heat exchanger 3 and the motor-operated valve 4, the indoor units U1 and U2 heat-exchange the air existing in the room with a refrigerant such as chlorofluorocarbon flowing into the indoor heat exchanger 3 and blow it out into the room. Indoor fan 9 and indoor heat exchanger 3
2 has a temperature sensor S1 for detecting the temperature of the refrigerant pipe and a temperature sensor S2 for detecting the temperature of the indoor air taken in when the indoor fan 9 is driven, each of which sends measurement data to the controller 10 of the outdoor unit U0. It is connected so as to transmit or operate based on a control signal output from this controller.

A switch for starting / stopping the system is provided in each of the indoor units U1 and U2.
There is a remote controller 11 having a switch for setting the room temperature, a switch for setting the wind speed (neither is shown), etc., and is electrically connected to the controller 10 so that various conditions for heating operation can be input. ing.

Further, a temperature sensor S3 for detecting the temperature on the inlet side of the refrigerant and a temperature sensor S4 for detecting the temperature on the outlet side of the refrigerant are provided at the refrigerant inlet / outlet portion of the outdoor heat exchanger 7 of the outdoor unit U0. The temperature data are connected so that they can be input to the controller 10.

The controller 10 is also connected to the outdoor expansion valve 6 so that the opening information of the expansion valve can be input, and the opening of the valve can be adjusted by a control signal output from the controller. Has become.

By operating the remote controller 11, operating conditions such as operation type, target room temperature, wind speed, temperature information measured by each temperature sensor S1, S2, S3, S4, and further information on the outdoor expansion valve 6 are displayed. The opening degree information is input to the memory unit of the controller 10, the control value is obtained by the arithmetic processing unit, and the control value is output.

The refrigerant compressed by the compressor 1 and discharged to the refrigerant pipe L can be circulated in two directions of a solid line and a broken line by switching the four-way valve 2 as described above.

When the heating circuit B shown by the broken line is formed, the refrigerant compressed by the compressor 1 and brought into a high temperature and high pressure state flows into the indoor units U1 and U2 via the four-way valve 2 and the respective units In the indoor heat exchanger 3, the indoor fan 9
Heat exchanges with the indoor air blown by the air, and the refrigerant itself cools and condenses. The indoor unit U1
The distribution control of the refrigerant to each U2 is performed by adjusting the opening degree of the electric valve 4 using a step motor or the like so as to correspond to each load.

The liquefied refrigerant is adiabatically expanded by the outdoor expansion valve 6 to become a gas body in a low temperature and low pressure state, and when passing through the outdoor heat exchanger 7, an outdoor fan (not shown).
Is warmed by the relatively high temperature outside air blown by
It recirculates to the compressor 1 via the four-way valve 2 and the accumulator 8.

During this heating operation, the indoor units U1.U
When either one of the two closes the motor-operated valve 4 and is in an operation stop state, and a large amount of liquid refrigerant accumulates in the indoor heat exchanger 3 of the stopped unit, and the refrigerant used for heating operation is insufficient, the outdoor heat exchange is performed. Since the temperature difference of the refrigerant at the inlet / outlet of the container 7 becomes larger than a predetermined temperature difference, the difference between the refrigerant temperatures measured by the temperature sensors S4 and S3 is compared with a standard value, so that the indoor unit which is not in operation can be operated. It is possible to reliably determine whether or not the liquid refrigerant stays and the heating capacity is insufficient.

For example, an example of a specific operation control performed by the controller 10 will be described with reference to the flowchart of FIG. 1 in which there are n indoor units (where n ≧ 2). The temperature T3 of the refrigerant flowing into the outdoor heat exchanger 7 measured by S3, the temperature T4 of the refrigerant flowing out of the outdoor heat exchanger 7 measured by the temperature sensor S4, and the opening degree of the outdoor expansion valve 6 are input.

In step P2, it is determined whether or not the outdoor heat exchanger 7 is out of refrigerant, that is, out of gas, based on a predetermined determination standard set in consideration of the characteristics peculiar to the apparatus, for example, FIG. .

For example, during heating operation with the opening of the outdoor expansion valve 6 set to 300 steps, the temperature T4 of the refrigerant flowing out of the outdoor heat exchanger 7 measured by the temperature sensor S4 and the temperature sensor S3 measured. If the temperature difference (T4-T3) from the temperature T3 of the refrigerant flowing into the outdoor heat exchanger 7 is 6 ° C, it is below the reference value, so it is determined that the refrigerant is not insufficient, and if it is 8 ° C, the opening degree is 300 steps. Therefore, it is determined that the flow rate of the refrigerant is small, and therefore the refrigerant temperature T4 on the outlet side abnormally rises and the temperature difference becomes large, and it is determined that the refrigerant is insufficient.

If it is determined as YES (insufficient refrigerant) in step P2, the process proceeds to step P3, and if NO is determined, the process returns to step P1.

In step P3, i = 1, that is, the first indoor unit U1 is selected, and in the following step P4, it is determined whether or not this indoor unit is performing heating operation.

If the answer is yes (during heating operation), there is no liquid refrigerant remaining in the indoor heat exchanger 3, so the routine proceeds to step P5, where it is determined whether i ≦ n is satisfied. In this case, since i = 1 and n ≧ 2, the process proceeds to step P6 on the Yes side, and the new i is set to i (= 1) + 1 =
Then, the process returns to step P4 as 2, and the same determination is made for the indoor unit U2.

The determination in step P4 is based on the determination in step P5.
While it is determined to be yes in step S21, that is, it is executed for all the indoor units Ui (i = 1 to n), and when it is determined to be no in step P5, the process returns to step P1.

The i-th indoor unit Ui, which is determined in step P4 that the heating operation is not being performed, is performed.
In step P7, the temperature T1 of the indoor heat exchanger 3 measured by the temperature sensor S1 of the unit Ui, the temperature T2 of the indoor air measured by the temperature sensor S2, and the setting state of the indoor fan 9 (stop, blow operation) (Medium etc.) is input, and the process proceeds to step P8.

In step P8, the temperature difference (T1-T2) between the indoor heat exchanger temperature T1 of the indoor unit Ui input in step P7 and the indoor air temperature T2 is calculated, and this is the first predetermined temperature, for example, 5 ° C. It is determined whether or not it is within the range, and when the determination is Yes, the process proceeds to step P9,
When it is determined no, the process returns to step P5.

For example, when the indoor air temperature T2 is 5 ° C., the refrigerant compressed by the compressor 1 into a high temperature / high pressure state is supplied to the indoor heat exchanger 3 of the indoor unit Ui which is not in operation, In a state where the refrigerant liquid hardly stays in the heat exchanger, the indoor heat exchanger temperature T1 measured by the temperature sensor S1 is measured.
Is, for example, 70 ° C., so the temperature difference (T1-T2)
Is large, the result of the determination in step P8 is no, and the process proceeds to step P5 to proceed to the determination of other indoor units.

However, if a large amount of the cooled, condensed, and liquefied refrigerant stays in the indoor heat exchanger 3, the indoor heat exchanger temperature T1 measured by the temperature sensor S1 decreases significantly, for example, 9 The temperature difference (T1-T2) is 4
When the temperature reaches 0 ° C., the determination in step P8 is YES, and the process proceeds to step P9 to collect the liquid refrigerant.

That is, in step P9, when the indoor fan 9 of the indoor unit Ui that is stopped is operating in the air blowing mode or the like, it is turned off, and
The electric valve 4 of the unit is slightly opened to a predetermined value, for example, 80 steps, and the liquid refrigerant is circulated.

When the operation of the indoor fan 9 is stopped, the liquid refrigerant staying in the indoor heat exchanger 3 is no longer cooled by the low temperature indoor air. Then, since the circulation through the electric valve 4 is started, the accumulated liquid refrigerant is promptly recovered.

In step P10, the indoor heat exchanger temperature T1 newly measured by the temperature sensor S1 and the temperature sensor S2 are measured.
Re-enters the newly measured indoor air temperature T2.

In step P11, the temperature difference (T1-T2) between the indoor heat exchanger temperature T1 and the indoor air temperature T2 input in step P10 is higher than the first predetermined temperature (5 ° C. in this case). It is determined whether or not a predetermined temperature of 2, for example, 10 ° C. is exceeded. If the retained liquid refrigerant circulates and is smoothly recovered, the refrigerant vapor that has been compressed by the compressor 1 and has a high temperature and high pressure is supplied to the indoor heat exchanger 3, so that the indoor heat exchange is performed. The chamber temperature T1 gradually rises,
For example, since the temperature reaches 70 ° C., the temperature difference (T1−T2) gradually increases. This temperature difference is the second predetermined temperature 1
When the temperature exceeds 0 ° C., it is determined that the liquid refrigerant has been completely recovered, and the process proceeds to step P12.

When it is determined NO in step P11, the process returns to step P10 after a predetermined time, the temperatures T1 and T2 are input again, and the determination in step P11 is performed again.

In step P12, the motor-operated valve 4 is closed and the indoor fan 9 is returned to its original state (weak wind, strong wind, etc.).

Since the present invention is not limited to the above embodiments, various modifications can be made without departing from the spirit of the claims.

For example, although the air conditioner capable of cooling and heating has been described as an example in the above embodiment, the present invention is also applicable to operation control of an air conditioner capable of only heating operation, and it is assumed that there are a plurality of indoor units. Although described, only one unit may be used.

[0041]

As described above, according to the present invention, the air conditioner is characterized in that the shortage of the refrigerant in the outdoor heat exchanger is determined from the difference between the opening of the outdoor expansion valve and the refrigerant inlet / outlet temperature difference of the outdoor heat exchanger. Operation control method in the machine,

Further, the air conditioner has a plurality of indoor units having an indoor heat exchanger and a blower fan, and the temperature difference between the heat exchanger temperature and the indoor temperature of the indoor unit in which the heating operation is stopped is the first. If the temperature is equal to or lower than the predetermined temperature of 1, the blower fan of the unit is stopped and the indoor electrically operated valve of the unit is opened to a predetermined opening, and the temperature difference is equal to or higher than a second predetermined temperature higher than the first predetermined temperature. At the same time, the operation control method in the air conditioner is characterized in that the indoor electric valve of the unit is closed and the blower fan of the unit is returned to the original setting state.

Since the indoor motor-operated valve is closed and the indoor heat exchanger of the indoor unit that is not in the heating operation is not supplied with the refrigerant vapor that has been compressed by the compressor and is in a high temperature / high pressure state, The temperature of the room in which the unit is placed does not rise, and the room temperature is not affected by the operating status of the indoor unit during the heating operation.

That is, since the refrigerant vapor is basically not supplied to the stopped indoor unit, not only the air-conditioning property of the room in which the indoor unit is at rest is improved but also the wasteful refrigerant is not used. Since there is no circulation, the thermal efficiency is improved and the coefficient of performance is improved.

Further, when the refrigerant stays in a liquid state in the indoor heat exchanger of the indoor unit which is not in the heating operation and the circulating refrigerant becomes insufficient, it is promptly detected and recovered.
The decrease in heating capacity is temporary and will not cause any problems.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an operation control method.

FIG. 2 is an explanatory diagram of refrigerant shortage determination.

FIG. 3 is a device configuration diagram of an embodiment.

[Explanation of symbols]

 1 Compressor 2 Four-way valve 3 Indoor heat exchanger 4 Motorized valve 5 Receiver tank 6 Outdoor expansion valve 7 Outdoor heat exchanger 8 Accumulator 9 Indoor fan 10 Controller 11 Remote controller S1, S2, S3, S4 Temperature sensor U0 Outdoor unit U1, U2 Indoor unit A Cooling circuit B Heating circuit L Refrigerant pipe

Claims (2)

[Claims] 1. An outdoor expansion valve in an air conditioner in which a heating circuit is formed by sequentially connecting a refrigerant compressor, an indoor heat exchanger, an indoor electric valve, an outdoor expansion valve, an outdoor heat exchanger, an accumulator, and the like. A method for controlling operation in an air conditioner, characterized in that a shortage of refrigerant in the outdoor heat exchanger is determined from the difference between the opening degree and the refrigerant inlet / outlet temperature difference of the outdoor heat exchanger. 2. An air conditioner in which a heating circuit is formed by sequentially connecting a refrigerant compressor, an indoor heat exchanger, an indoor electric valve, an outdoor expansion valve, an outdoor heat exchanger, an accumulator, etc. Has a plurality of indoor units having an indoor heat exchanger and a blower fan, and the temperature difference between the heat exchanger temperature and the indoor temperature of the indoor unit in which the heating operation is stopped is the first
If the temperature is equal to or lower than the predetermined temperature, the blower fan of the unit is stopped and the indoor electric valve of the unit is opened to a predetermined opening, and the temperature difference becomes equal to or higher than the second predetermined temperature higher than the first predetermined temperature. At times, the indoor electric valve of the unit is closed, and the blower fan of the unit is returned to the original setting state.