JPH09269160A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To change modes of an outdoor air conditioner device and an indoor air conditioner device within a minimum short period of time without stopping an operation of each of the devices and improve a rising characteristic in operation after changing modes. SOLUTION: A plurality of indoor air conditioners 50A, 50B are connected in parallel with an outdoor air conditioner through a branch device 40. There are provided a first connecting means comprised of flow rate adjusting valves 5A, 5B and a second connecting means comprised of flow rate adjusting valves 5A, 5B. When a mode is changed, refrigerant pressure within heat exchangers 6, 18 is decreased or increased while the flow rate of refrigerant is being restricted and conducted. When a pressure difference across the connecting means is lower than a predetermined value, full opened communication causes an operation of each of the devices to be started under a new mode setting within a minimum period of time. In addition, the flow rate adjusting valves 25, 14 adjacent to the expansion valves 7, 15 are fully opened only for a specified period of time, flush gas between the expansion valve and the flow rate adjusting valve is removed and its rising characteristic is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-type air conditioner comprising an air conditioner and a plurality of indoor air conditioners, which is used for air conditioning of a building or the like.

[0002]

2. Description of the Related Art In recent years, air conditioning in buildings and the like has become diversified, and it is no longer as simple as cooling in summer and heating in winter. In other words, inside the building, the season, the direction and position of the room,
There is a case where it is desired to simultaneously perform the cooling operation and the heating operation in the air conditioning system due to the load of the OA equipment or the like. For example, there is a case where it is desired to perform a cooling operation in an interior zone in a building and perform a heating operation in a perimeter zone. In addition, heating operation may be required in the morning and evening in the middle of spring and autumn, and cooling operation may be required in the daytime. And in this case, the switching timing between the cooling operation and the heating operation differs depending on the direction of the air conditioning zone, and the condition to switch to the cooling operation is reached on the south side,
On the north side, heating operation may still need to be continued. Further, in a place with a heavy load such as OA equipment, it may be necessary to perform cooling operation all day even in winter. Moreover, it is necessary to continuously switch these operation modes without stopping the equipment.

To meet these demands, there is an air conditioner called a 4-pipe type air handling unit. This is an air conditioner that has two built-in heat exchangers dedicated to cooling and heating, and can freely change the supply air temperature from cooling to heating according to the air conditioning load. In addition, there is also a method called a dual duct method, in which air supply from two air handling units dedicated to cooling and heating is mixed to perform air conditioning. However, since both heat sources for cooling and heating are prepared and the waste heat of each is discarded, there is a tendency to refrain from adopting it because it is against energy conservation and because of frequent occurrence of water leaks in pipes.

Therefore, there is a case where a heat pump multi-air conditioner capable of simultaneous cooling and heating operation and using no water is adopted. This is composed of one outdoor unit and multiple indoor units. The indoor unit is installed in each air conditioning zone, and the outdoor unit and the indoor unit are connected by a pipe composed of a liquid pipe, a high pressure gas pipe and a low pressure gas pipe. The individual indoor unit is an air conditioner that can freely perform cooling and heating operations, and is used because it saves energy and costs at the same time during simultaneous cooling and heating operations. However, if this heat pump multi air conditioner is installed for building air conditioning, the indoor unit is switched from cooling operation to heating operation or vice versa depending on the air conditioning load condition, or the heat exchanger of the outdoor unit is changed from evaporation mode to condensation mode, Or vice versa, switching frequently occurs. Therefore, the solenoid valve has to be switched, and each time the device has to be stopped and operated for a long time, or if it is operated without stopping, abnormal noise occurs.

As a countermeasure against this abnormal noise, for example, Japanese Unexamined Patent Publication No.
There is one disclosed in Japanese Patent Laid-Open No. 203275. this is,
In a simultaneous heating / cooling heat pump multi-air conditioner, a first indoor side switching valve is provided between the discharge pipe (high pressure gas pipe) coming from the outdoor unit and the indoor unit, and the suction pipe (low pressure gas pipe) coming from the outdoor unit. A second indoor side switching valve is provided between the indoor unit and the indoor unit. A first bypass circuit is connected in parallel to the first indoor side switching valve, and a second bypass circuit is connected to the second indoor side switching valve.

When switching from the heating operation to the cooling operation, in the indoor unit, the state in which the expansion valve is fully closed and the first indoor-side switching valve is closed is maintained for a predetermined time, and then the second bypass circuit is turned on. It is controlled to close and open the second indoor-side switching valve, the first bypass circuit and the expansion valve. When switching from the cooling operation to the heating operation, the second indoor side switching valve and the second bypass circuit are closed, and the expansion valve is fully closed for a predetermined time, and then the first bypass circuit. Is closed and the first indoor-side switching valve, the second bypass circuit and the expansion valve are opened.

[0007]

However, although this heat pump multi-air conditioner is capable of simultaneous cooling and heating operation, it does not control the blowing temperature, and it is not possible to obtain any blowing temperature from cooling to heating. . Furthermore, since it is not possible to control the distribution of refrigerant between multiple indoor units arbitrarily, and the capacity control of the compressor is not sufficient, the blowout temperature is also different. It is hard to say that room temperature controllability is good because the valve is closed and the function is stopped. Further, since it is an indoor air circulation type air conditioning system, an outside air processing device must be newly installed for each indoor unit for the outside air processing function, which causes a problem that equipment cost is required.

Further, in the above heat pump multi-air conditioner, the mode of the indoor unit may be switched while the compressor is operating, but when the mode of the indoor unit is changed, the compressor is stopped and the pressure in the pipe is equalized. You have to wait for it to be done, while you have to shut down the equipment. Further, although the first and second bypass circuits are designed to be opened for a predetermined time when the mode is changed,
The differential pressure between the front and rear varies depending on the operating state of the refrigeration cycle, and the time required for pressure equalization varies each time. In order to cover this and surely prevent abnormal noise, there is no choice but to set a long time for keeping the bypass circuit open, which is unsuitable for a building air conditioner that needs to be changed immediately.

Therefore, in view of the above-mentioned conventional problems, the present invention can control the supply air temperature in an air conditioner equipped with an external air conditioner and a plurality of indoor air conditioners, and can quickly and freely operate without stopping the compressor. An air conditioner that can switch the indoor air conditioner from cooling operation to heating operation, or from heating operation to cooling operation, and also can switch the heat exchanger of the external controller from evaporation mode to condensation mode or from condensation mode to evaporation mode The purpose is to provide.

[0010]

To this end, the present invention provides an external conditioner including a heat exchanger, an expansion valve attached to the heat exchanger, and a flow rate adjusting valve provided in series with the expansion valve, A heat exchanger, an expansion valve attached to the heat exchanger, a flow rate adjustment valve provided in series with the expansion valve, and a refrigerant pipe forming a liquid pipe, a high pressure gas pipe, and a low pressure gas pipe of a refrigeration cycle. In an air conditioner comprising a plurality of indoor air conditioners connected in parallel to an external air conditioner, each of the indoor air conditioners being selectively controlled for cooling operation or heating operation, a heat exchanger for the external air conditioner. And a high-pressure gas pipe connected to a heat exchanger of an indoor air conditioner by connecting a gas pipe connected to the Alternatively, the second low pressure gas pipe is connected by a second connecting means capable of adjusting the flow rate. It was what was.

In particular, the above-mentioned first connecting means is such that when the heat exchanger of the external conditioner is changed from the evaporation mode to the condensation mode, the pressure inside the heat exchanger of the external conditioner and the pressure of the high pressure gas pipe are predetermined. When the heat exchanger of the external controller changes from the condensation mode to the evaporation mode while conducting the refrigerant from the high pressure gas pipe while limiting the pressure so that it is maintained above the pressure difference of Passing the refrigerant through the low-pressure gas pipe while limiting the pressure of the low-pressure gas pipe to be maintained at a predetermined pressure difference or more,
When the pressure difference becomes smaller than a predetermined value, they are connected so as to be fully opened, and the second connecting means is provided for the indoor air conditioner when the heat exchanger of the indoor air conditioner is changed from heating operation to cooling operation. The refrigerant is conducted to the low pressure gas pipe while limiting the pressure in the heat exchanger and the pressure of the low pressure gas pipe so as to be maintained at a predetermined pressure difference or more, and the heat exchanger of the indoor air conditioner is changed from the cooling operation to the heating operation. When changing the pressure inside the heat exchanger of the indoor air conditioner and the pressure of the high-pressure gas pipe are controlled so as to be maintained at a predetermined pressure difference or more, and the refrigerant is conducted from the high-pressure gas pipe, and each pressure difference has a predetermined value. It can be configured to be in full open communication when smaller.

Furthermore, the flow control valve of the external regulator is closed when the evaporation mode is changed to the condensation mode or when the condensation mode is changed to the evaporation mode, and only for a predetermined time after the limited conduction by the first connecting means. It is preferably configured to be opened to a predetermined opening degree to remove the gaseous refrigerant near the expansion valve of the external pressure regulator. Further, the flow rate control valve of the indoor air conditioner is also closed at the time of changing from the heating operation to the cooling operation or from the cooling operation to the heating operation, and after a limited conduction by the second connecting means, a predetermined opening degree for a predetermined time. It is preferably configured to be opened to remove gaseous refrigerant near the expansion valve of the indoor air conditioner.

Each of the first connecting means and the second connecting means can be composed of an electronic flow rate adjusting valve whose opening is controlled. Alternatively, the first connecting means or the second connecting means is configured by a main solenoid valve and a bypass circuit in which the sub solenoid valve and the capillary are connected in series and connected in parallel to the main solenoid valve, and the main solenoid valve is It is also possible to provide a limited conduction by opening the closed bypass circuit and then to transfer to the connection by the main solenoid valve.

[0014]

[Function] When changing between the evaporation mode and the condensation mode of the heat exchanger of the external air conditioner or between the cooling operation and the heating operation of the indoor air conditioner, first, the refrigerant flow rate is limited by the first or second connecting means. The refrigerant pressure in the heat exchanger is reduced or increased by making it conductive. This prevents the generation of abnormal noise when changing. In particular, when the pressure difference before and after the connecting means becomes equal to or less than a predetermined value, the full-open communication is performed, so that the operation in the new mode is started with the minimum required time for switching.

Further, by opening the flow control valve of the external air conditioner or the indoor air conditioner to a predetermined opening for a predetermined time when the operation of the new mode is started, the flash gas near the expansion valve such as between the expansion valve and the flow control valve is opened. Etc. are removed.

[0016]

1 shows a refrigerant circuit according to a first embodiment of the present invention. In this embodiment, the two indoor air conditioners 50A and 50B are connected via a branch unit 40 to a liquid pipe,
A refrigerant pipe R1 forming a low pressure gas pipe and a high pressure gas pipe,
The external modulator 30 is connected in parallel by R2 and R3. The external air conditioner 30 includes a compressor 1 having a variable capacity and a heat exchanger 6. The discharge side and suction side pipes of the compressor 1 are provided with pressure sensors 11A and 11B, respectively.

The external conditioner 30 further includes a branch unit 40.
A liquid tank 27, an electronic flow rate adjusting valve 25, and an electronic expansion valve 7 are attached in this order from the refrigerant pipe R1 to the heat exchanger 6 direction. A pressure sensor 8 is attached to the refrigerant pipe (gas pipe) on the other end side of the heat exchanger 6, and
It is connected to the refrigerant pipe R2 via an electronic flow rate adjusting valve 5A, and is also connected to the refrigerant pipe R3 via a flow rate adjusting valve 5B. The refrigerant pipe R2 is also connected to the accumulator 3, and the refrigerant pipe R3 is connected to the discharge side of the compressor 1. Further, the heat exchanger 6 is provided with a blower 21.

The branch unit 40 is an electronic flow control valve 1
3A, 13B, 23A, 23B are provided, and the flow rate adjusting valves 13A, 13B enable the indoor air conditioners 50A, 50B to communicate with the refrigerant pipe R2, respectively, and the flow rate adjusting valves 23A, 23B.
B is a refrigerant pipe R3 for the indoor air conditioners 50A and 50B, respectively.
Can communicate with

The indoor air conditioner 50A includes a heat exchanger 18A,
It has a blower 24A attached thereto. Heat exchanger 18
One end of A passes through the branch unit 40 and the refrigerant pipe R1.
The flow control valve 1 of the branch unit 40 is connected to
Connected to 3A and 23A. The refrigerant pipe R1 on one end side of the heat exchanger 18A is provided with an electronic flow rate adjusting valve 14A and an electronic expansion valve 15A in the order from the branch unit 40 in the direction of the heat exchanger 18A. A pressure sensor 16A is provided on the opposite side of the heat exchanger 18A. The air supplied by the heat exchanger 18A and blown out by the blower 24A is guided to the air conditioning zone by the duct. The indoor air conditioner 50B is also configured in the same manner as the indoor air conditioner 50A, and each reference numeral is indicated by adding B.

FIG. 2 shows a control device for the indoor air conditioner and the outdoor air conditioner. The control device consists of a microcomputer and its peripherals. That is, the air conditioner control unit 31 includes, as peripheral devices for the external air conditioner, the drive control unit 34 for the expansion valve 7, the drive control unit 48 for the flow rate adjusting valves 25, 5A, 5B, and the pressure sensors 8, 11A, 11B. Pressure converter 37 for, inverter circuit 32 for compressor 1
Is connected.

On the other hand, as control devices for the indoor air conditioner 50A, a drive control unit 39A for the expansion valve 15A, a drive control unit 41A for the flow rate adjusting valves 14A, 13A, 23A, and a pressure converter 43A for the pressure sensor 16A are provided. Air conditioner controller 31
It is connected to the. As for the control device for the indoor air conditioner 50B, the same control device as the control device for the indoor air conditioner 50A is connected, and B is attached to each reference number.
The air conditioner control unit 31 calculates the load amount of the indoor air conditioners 50A and 50B and drives the compressor 1.

Next, the operation of the above configuration will be described. FIG. 3 shows the flow of the refrigerant during the cooling only operation in which all the indoor air conditioners are cooled. When all indoor air conditioners are in cooling operation, the flow rate adjustment valve 5
B is in a fully open state, the flow rate adjusting valve 5A is in a fully closed state, and in the branch unit, the flow rate adjusting valves 13A and 13B are in a fully open state and 23A and 23B are in a fully closed state. The heat exchanger 6 of the external air conditioner acts as a condenser, and the heat exchangers 18A and 18B of each indoor air conditioner act as evaporators.

That is, in the external conditioner 30, the high-pressure gas refrigerant from the compressor 1 passes through the flow rate adjusting valve 5B as shown by the arrow and is liquefied in the heat exchanger 6. Then, the refrigerant is branched from the branch pipe through the liquid tank 27, the refrigerant pipe R1, and the branch unit 40, enters the flow rate adjusting valves 14A and 14B in parallel, and is subsequently decompressed by the expansion valves 15A and 15B, so that the low temperature gas-liquid is obtained. It becomes a mixed state. Next, the refrigerant is heat-exchanged with the return air in the heat exchangers 18A and 18B to become a gaseous refrigerant. Then, the flow returns to the compressor 1 via the flow rate adjusting valves 13A and 13B, the refrigerant pipe R2 and the accumulator 3. The flow rate adjusting valves 5A, 5B constitute the first connecting means of the invention, and the flow rate adjusting valves 13A, 13B, 23A, 2
3B constitutes the second connecting means.

During this time, the expansion valve 7, the flow rate adjusting valve 25 of the external air conditioner 30, the flow rate adjusting valves 14A, 14B and the expansion valves 15A, 15B of the indoor air conditioners 50A, 50B are controlled as follows. First, the expansion valve 7 is held in the fully opened state by the air conditioner control unit 31. The opening of the flow rate adjusting valve 25 is controlled by the load states of the indoor air conditioners 50A and 50B. Further, the flow rate adjusting valves 14A and 14B are used for the indoor air conditioner 50.
The opening is controlled by the supply air temperatures of A and 50B. The expansion valves 15A and 15B are controlled by the degree of superheat of the heat exchangers 18A and 18B. That is, the flow rate adjusting valves 14A and 14B control the capacity of the indoor air conditioners 50A and 50B.

Next, the flow of the refrigerant during the heating only operation in which all the indoor air conditioners are heated will be described with reference to FIG. When all the indoor air conditioners are operated for heating, the flow rate adjusting valve 5A is fully opened in the external air conditioner.
B is in the fully closed state, in the branch unit 40, the flow rate adjusting valves 23A and 23B are in the fully open state, and the flow rate adjusting valve 13A and
13B is controlled so as to be fully closed. The heat exchanger 6 of the external air conditioner 30 is an evaporator, the heat exchanger 18A of each indoor air conditioner,
18B acts as a condenser.

That is, the high-pressure gas refrigerant from the compressor 1 of the external conditioner 30 enters the branch unit 40 via the refrigerant pipe R3. The refrigerant is branched here, and the flow rate adjusting valve 23
After passing through A and 23B, they enter the heat exchangers 18A and 18B of the indoor air conditioners 50A and 50B and are liquefied. after this,
After passing through the expansion valves 15A and 15B and the flow rate adjusting valves 14A and 14B, the branch unit 40 and the refrigerant pipe R1 are passed and the external conditioner 3
The liquid tank 27 of 0 enters. Further, the refrigerant discharged from the liquid tank 27 enters the expansion valve 7 via the flow rate adjusting valve 25 and is decompressed,
A low-temperature gas-liquid mixed state is established and the heat exchanger 6 is entered. The refrigerant exchanges heat with the outside air in the heat exchanger 6 to become a gas, enters the accumulator 3 via the flow rate adjusting valve 5A, and enters the compressor 1
Return to

During this time, the flow rate adjusting valves 14A, 14
B, expansion valves 15A and 15B, flow rate adjusting valve 25, expansion valve 7
Is controlled as follows. First, the air conditioner control unit 3
1, the flow rate adjusting valves 14A and 14B are connected to the indoor air conditioner 50.
The opening degree is controlled by the supply air temperatures of A and 50B. Expansion valve 1
5A and 15B are held fully open. In addition, the flow rate adjustment valve 2
The opening 5 is controlled by the temperature of the indoor air conditioners 50A and 50B. The expansion valve 7 is controlled by the degree of superheat of the heat exchanger 6.

Next, the control in the case where the cooling operation and the heating operation are performed in parallel is the same as the control of the flow rate adjusting valve and the expansion valve of the indoor air conditioner in the cooling operation,
The flow control valve and expansion valve of the indoor air conditioner in the heating operation are the same as the control of the indoor air conditioner in the heating only operation. Then, when the cooling load of the indoor air conditioner is larger than the heating load, the heat exchanger of the external air conditioner acts as a condenser so that the flow control valve of the external air conditioner and the expansion valve are controlled. When the heating load of the indoor air conditioner is larger than the cooling load, the heat exchanger of the external air conditioner acts as an evaporator, so that it becomes the same as the external air conditioner during the heating only operation.

Next, the operation when the indoor air conditioner is changed from the cooling operation to the heating operation will be described. First, when the indoor air conditioner 50A is in the cooling operation, the refrigerant flows through the indoor air conditioner 50A in FIG. 3 as indicated by the arrow. Here, when the indoor air conditioner 50A becomes a condition for switching to the heating operation, the air conditioner control unit 31 first determines the flow rate adjusting valves 14A, 1
Fully close 3A. Further, the expansion valve 15A is fully opened.
Next, when the flow rate adjusting valve 23A is opened by an intermediate opening degree to introduce the refrigerant from the refrigerant pipe R3 into the pipes of the heat exchanger 18A and the indoor air conditioner 50A, the pressure of the heat exchanger 18A rises. Here, the air conditioner control unit 31 detects the pressure around the flow rate adjusting valve 23A from the pressure sensors 16A and 11A, and calculates the differential pressure.
Then, this state is maintained until it becomes less than or equal to a predetermined value. In other words, the flow rate is restricted as a result of the flow control valve 23A being suppressed to the intermediate opening degree, the flow is restricted, and the pressure in the heat exchanger 18A and the pressure in the refrigerant pipe R3, which is a high-pressure gas pipe, are maintained at a predetermined pressure difference or more, This state continues until the pressure difference gradually decreases toward the pressure equalizing direction.

Next, when the differential pressure becomes equal to or lower than a predetermined value, the flow rate adjusting valve 23A is fully opened. Further, the flow rate adjusting valve 14A is opened to almost full opening for a predetermined time.
At this time, the flash gas accumulated in the heat exchanger 18A and before and after the expansion valve 15A can be released to the refrigerant pipe R1. Next, the flow rate adjusting valve 14A is driven in the closing direction, after which the flow rate adjusting valve 14A is controlled by the supply air temperature of the indoor air conditioner 50A, and the indoor air conditioner 50A starts heating operation.
The flow of the refrigerant at this time flows like the indoor air conditioner 50A in FIG.

Next, the operation when the indoor air conditioner is changed from the heating operation to the cooling operation will be described. First, when the indoor air conditioner 50A is in the heating operation, the refrigerant flows in the indoor air conditioner 50A in FIG. 4 as shown by the arrow. Here, when the indoor air conditioner 50A becomes a condition for switching to the cooling operation, the air conditioner controller 31 first causes the flow rate adjusting valves 14A, 2
Fully close 3A. Next, when the flow rate adjusting valve 13A is opened by an intermediate opening degree and the refrigerant in the pipes inside the heat exchanger 18A and the indoor air conditioner 50A is released to the refrigerant pipe R2, the pressure inside the heat exchanger 18A drops. Here, the air conditioner control unit 31 detects the pressure around the flow rate adjusting valve 13A from the pressure sensors 16A and 11B, and calculates the differential pressure. Then, this state is maintained until it becomes less than or equal to a predetermined value. In other words, the flow control valve 1
As a result of 3A being suppressed to an intermediate opening degree, the flow is restricted, and the pressure in the heat exchanger 18A and the refrigerant pipe R2 which is a low pressure gas pipe
Is maintained above a predetermined pressure difference, and this state continues until the pressure difference gradually decreases toward the pressure equalizing direction.

Next, when the differential pressure becomes equal to or lower than a predetermined value, the flow rate adjusting valve 13A is fully opened. Further, the flow rate adjusting valve 14A is fully opened and the expansion valve 15A is almost fully opened for a predetermined time. At this time, the flash gas accumulated between the expansion valve 15A and the flow rate adjusting valve 14A can be released to the heat exchanger 18A. Next, the expansion valve 15A and the flow control valve 14A are driven in the closing direction, and then the expansion valve 1
5A is controlled by the degree of superheat of the heat exchanger 18A, the flow rate adjusting valve 14A is controlled by the supply air temperature of the indoor air conditioner 50A, and the indoor air conditioner starts cooling operation. The flow of the refrigerant at this time flows like the indoor air conditioner 50A in FIG.

Next, the operation when the heat exchanger 6 of the external conditioner 30 is changed from the evaporation mode to the condensation mode will be described. First, when the heat exchanger 6 of the external conditioner 30 is operated in the evaporation mode, the refrigerant flows in the external conditioner 30 of FIG. 4 as indicated by the arrow. When the heat exchanger 6 of the external air conditioner 30 is in a condition where the heat exchanger 6 should be switched to the condensation mode, the air conditioner controller 31 first fully closes the flow rate adjusting valves 25 and 5A. Further, the expansion valve 7 is fully opened. Next, when the flow rate adjusting valve 5B is opened by an intermediate opening degree, the refrigerant is introduced into the heat exchanger 6 from the refrigerant pipe R3, and the pressure in the heat exchanger 6 rises. Here, the air conditioner control unit 31 controls the flow rate adjusting valve 5 from the pressure sensors 8 and 11A.
The pressure before and after B is detected, and the differential pressure is calculated. Then, this state is maintained until it becomes less than or equal to a predetermined value. In other words, the flow is restricted as a result of the flow rate control valve 5B being suppressed to the intermediate opening degree, the flow is restricted, and the pressure in the heat exchanger 6 and the pressure in the refrigerant pipe R3, which is a high-pressure gas pipe, are maintained at a predetermined pressure difference or more, This state continues until the pressure difference gradually decreases toward the pressure equalizing direction.

Next, when the differential pressure becomes equal to or lower than a predetermined value, the flow rate adjusting valve 5B is fully opened. Further, the flow rate adjusting valve 25 is opened to almost full opening for a predetermined time. At this time, the flash gas accumulated in the heat exchanger 6 and around the expansion valve 7 can be released to the refrigerant pipe R1. Next,
After the flow rate adjusting valve 25 is driven in the closing direction, it is controlled by the loads of the indoor air conditioners 50A and 50B, and the heat exchanger 6 of the external air conditioner 30 starts operating in the condensation mode. The flow of the refrigerant at this time flows like the external air conditioner 30 in FIG.

Next, the operation when the heat exchanger 6 of the external conditioner 30 is changed from the condensation mode to the evaporation mode will be described. First, when the heat exchanger 6 of the external conditioner 30 is operated in the condensation mode, the refrigerant flows in the external conditioner 30 of FIG. 3 as indicated by the arrow. Here, when the heat exchanger 6 of the external air conditioner 30 becomes a condition for switching to the evaporation mode, the air conditioner control unit 31 first fully closes the flow rate adjusting valves 25, 5B. Next, when the flow rate adjusting valve 5A is opened by the intermediate opening degree, the refrigerant in the heat exchanger 6 escapes to the refrigerant pipe R2 and the pressure falls. here,
The air conditioner control unit 31 detects the pressure around the flow rate adjusting valve 5A from the pressure sensors 8 and 11B, and calculates the differential pressure. Then, this state is maintained until it becomes less than or equal to a predetermined value. In other words, the flow is restricted as a result of the flow rate control valve 5A being suppressed to the intermediate opening degree, and the pressure inside the heat exchanger 6 and the pressure in the refrigerant pipe R2, which is a low-pressure gas pipe, are maintained at a predetermined pressure difference or more, This state continues until the pressure difference gradually decreases toward the pressure equalizing direction.

Next, when the differential pressure becomes equal to or lower than a predetermined value, the flow rate adjusting valve 5A is fully opened. Further, the flow rate adjusting valve 25 is fully opened and the expansion valve 7 is fully opened for a predetermined time. At this time, the flash gas accumulated between the expansion valve 7 and the flow rate adjusting valve 25 can be released to the heat exchanger 6. Next, the expansion valve 7 and the flow rate adjusting valve 25 are driven in the closing direction, after which the expansion valve 7 is controlled by the superheat degree of the heat exchanger 6, and the flow rate adjusting valve 25 is controlled by the load of the indoor air conditioners 50A and 50B. Then, the heat exchanger 6 of the external air conditioner 30 starts to operate in the evaporation mode.

The control flow when the mode of the indoor air conditioner and the external air conditioner in the air conditioner control section 31 is changed is briefly shown in FIGS. 5, 6 and 7 and 8. FIG.
Shows the flow when changing from cooling operation to heating operation in the indoor air conditioner. First, in step 100, a normal cooling operation is performed, and in the next step 101, a mode determination is made as to whether or not the indoor air conditioner should be changed to heating operation. If the cooling operation should be continued, the process returns to step 100. When the heating operation should be changed, the process proceeds to step 102.

In step 102, first the flow rate adjusting valve 14
A and 13A are fully closed, the expansion valve 15A is fully opened, and the flow rate adjustment valve 23A is opened by an intermediate opening degree, and the heat exchanger 18A is opened.
Increase the internal pressure. In the next step 103, the respective pressures are detected by the pressure sensors 16A and 11A,
In step 104, the differential pressure is compared with a predetermined value set in advance, and after waiting until the differential pressure becomes smaller than the predetermined value, the process proceeds to step 105.

In step 105, the flow rate adjusting valve 23A is fully opened and the flow rate adjusting valve 14A is almost fully opened. Then, in step 106, after confirming that the state of step 105 is maintained for a predetermined time, the process proceeds to step 107.
In step 107, the opening degree of the flow rate adjusting valve 14A is controlled and driven in the closing direction, and then the heating operation is controlled in step 108.

Next, FIG. 6 shows the flow when the heating operation in the indoor air conditioner is changed to the cooling operation. First step 1
In 10 the normal heating operation is performed, and in the next step 111, a mode determination is made as to whether or not the indoor air conditioner should be changed to the cooling operation. If the heating operation should be continued, the process returns to step 110. If the cooling operation should be performed, the process proceeds to step 112. In step 112, first, the flow rate adjusting valves 14A and 23A are fully closed, the expansion valve 15A is fully opened, and the flow rate adjusting valve 13A is opened by an intermediate opening degree to reduce the pressure in the heat exchanger 18A.

In the next step 113, the pressure sensor 1
Detect each pressure from 6A and 11B, and step 1
In step 14, the differential pressure is compared with a predetermined value set in advance, and after waiting until the differential pressure becomes smaller than the predetermined value, the routine proceeds to step 115. In step 115, the flow rate adjusting valve 13A is fully opened, and the flow rate adjusting valve 14A and the expansion valve 15A are almost fully opened. Then, in step 116, after confirming that the state of step 115 is maintained for a predetermined time, step 117
Proceed to. In step 117, the opening amounts of the flow rate adjusting valve 14A and the expansion valve 15A are controlled and driven in the closing direction, and step 118
Move on to control of air conditioning operation.

The switching control between the heating operation and the cooling operation in the indoor air conditioner shown in FIGS. 5 and 6 is continuously executed during the operation of the air conditioner, and step 108 in FIG. 5 corresponds to step 108 in FIG. Step 110 is reached, and FIG.
Step 118 in FIG.
Becomes

FIG. 7 shows the flow at the time of changing from the condensation mode to the evaporation mode in the external air conditioner. First, in step 200, a normal condensation mode operation is performed, and in the next step 201, a mode determination is made as to whether or not the external air conditioner should be changed to the evaporation mode. Here, if the condensed mode operation should be continued, the process returns to step 200. Also,
If it should be changed to evaporation mode operation, step 2
Go to 02. In step 202, first, the flow rate adjusting valve 2
5, 5B are fully closed, the expansion valve 7 is fully opened, and the flow rate adjustment valve 5A is opened by an intermediate opening degree to reduce the pressure in the heat exchanger 6.

In the next step 203, the respective pressures are detected by the pressure sensors 8 and 11B, and step 20
In step 4, the differential pressure is compared with a predetermined value set in advance, and after waiting until the differential pressure becomes smaller than the predetermined value, the routine proceeds to step 205. In step 205, the flow rate adjusting valve 5B is fully opened, and the flow rate adjusting valve 25 and the expansion valve 7 are almost fully opened. Then, in step 206, after confirming that the state of step 205 is maintained for a predetermined time, the process proceeds to step 207. In step 207, the opening degrees of the flow rate adjusting valve 25 and the expansion valve 7 are controlled in the closing direction, and the evaporation mode operation of step 208 is started.

Next, FIG. 8 shows a flow at the time of changing from the evaporation mode to the condensation mode in the external air conditioner. First step 2
In step 10, the normal evaporation mode operation is performed, and in the next step 211, a mode determination is made as to whether or not the external air conditioner should be changed to the condensation mode. Here, if the evaporation mode operation is to be continued, the process returns to step 210.
If the operation should be changed to the condensed mode operation, the process proceeds to step 212. In step 212, first, the flow rate adjusting valves 25 and 5A are fully closed, the expansion valve 7 is fully opened, and the flow rate adjusting valve 5B is opened by an intermediate opening degree to increase the pressure in the heat exchanger 6.

At the next step 213, the respective pressures are detected by the pressure sensors 8 and 11A, and step 21
In step 4, the differential pressure is compared with a predetermined value set in advance, and after the differential pressure becomes smaller than the predetermined value, the process proceeds to step 215. In step 215, the flow rate adjusting valve 5B is fully opened,
The flow rate adjusting valve 25 is almost fully opened. And step 2
After confirming in step 16 that the state of step 215 is held for a predetermined time, the process proceeds to step 217. Step 217
Then, the flow rate adjusting valve 25 is controlled and driven in the closing direction, and the condensation mode operation of step 218 is started.

The switching control between the operation of the condensation mode and the operation of the evaporation mode in the air conditioner shown in FIGS. 7 and 8 is continuously executed during the operation of the air conditioner, and step 208 in FIG. Step 210 in
Step 218 in FIG. 8 corresponds to step 2 in FIG.
00.

This embodiment is configured as described above, the external air conditioner and a plurality of indoor air conditioners are connected in parallel, and the gas pipes of the heat exchangers of the external air conditioner and each indoor air conditioner are either high pressure gas pipes or low pressure gas pipes. In an air conditioner that connects the gas pipes with flow rate adjustment valves, when switching between the condensation mode and evaporation mode operations of the external air conditioner and between the cooling operation and the heating operation of the indoor air conditioner, After opening the adjustment valve by an intermediate opening, the pressure of the refrigerant in the heat exchanger is reduced or increased, and the pressure difference between the refrigerant pressure in the heat exchanger and the high-pressure gas pipe or the low-pressure gas pipe is set below a specified value. I tried to open it fully. As a result, the switching can be performed in the minimum time according to the operating condition of the refrigeration cycle.

Further, since the pressure difference before and after the flow rate adjusting valve at the time of switching is relaxed and the refrigerant does not suddenly flow, no abnormal noise is generated. Further, since the flash gas accumulated between the expansion valve and the flow rate adjusting valve for controlling the refrigerant flow rate is opened for a predetermined time to remove the flash gas, the controllability of the flow rate adjusting valve and the expansion valve may be impaired. Instead, the rising characteristics after switching are improved.

FIG. 9 shows a second embodiment of the present invention. This embodiment differs from the refrigerant circuit of the first embodiment described above in that the flow rate adjusting valves 5A and 5B in the external regulator and the flow rate adjusting valves 13A, 13B, 23A, and 23B in the branch unit are respectively replaced. The main solenoid valve allows switching, and a bypass circuit in which a sub solenoid valve that can be opened and closed and a pressure reducing capillary are connected in series is connected in parallel to each main solenoid valve.

That is, the main unit solenoid valves 63A, 63B, 66A, 66B are provided in the branch unit 40 ', and the main solenoid valves 63A, 63B are respectively used for the indoor air conditioners 50A, 50.
B can be communicated with the refrigerant pipe R2, and main solenoid valves 66A, 6
6B is a refrigerant pipe R for the indoor air conditioners 50A and 50B, respectively.
Communication with 3 is possible. In addition, the main solenoid valves 63A, 63B,
Bypass circuits are connected in parallel to 66A and 66B, respectively, and depressurizing capillaries 65A and 6 are provided in the bypass circuits.
5B, 68A, 68B and auxiliary solenoid valves 64A, 64B, 67
A and 67B are respectively provided in series.

Also in the external conditioner 30 ', the refrigerant pipe on the gas pipe side of the heat exchanger 6 is connected to the refrigerant pipe R2 via the main solenoid valve 60A, and is connected to the refrigerant pipe R3 via the main solenoid valve 60B. There is. A bypass circuit is connected to each of the main solenoid valves 60A and 60B, and capillaries 62A and 62B for pressure reduction and sub solenoid valves 61A and 61B are provided in series in the bypass circuits. Other configurations are the same as those of the first embodiment. The flow of the refrigerant in each operation mode is also the same as in the first embodiment.

When changing the operation mode,
For the piping side to be newly connected, first open the bypass solenoid valve of the bypass circuit with the main solenoid valve closed. As a result, the refrigerant is restricted by the capillaries, reduced in pressure, and conducted. When the pressure difference before and after that falls below a predetermined value, the main solenoid valve is opened and the sub solenoid valve is closed.

In this embodiment, the main solenoid valves 60A and 60B are
And capillaries 62A respectively attached to these,
The bypass circuit including 62B and the auxiliary solenoid valves 61A and 61B constitutes the first connecting means of the invention, and the main solenoid valves 63A and 6A are provided.
A bypass circuit including 3B, 66A, 66B and capillaries 65A, 65B, 68A, 68B respectively attached thereto and sub solenoid valves 64A, 64B, 67A, 67B constitutes the second connecting means.

In this embodiment, when the heat exchanger of the indoor air conditioner or the external air conditioner is switched between the operation modes, when the flow rate adjusting valve should be opened to the intermediate opening in the first embodiment, the bypass circuit is used instead. By passing through the capillaries, the capillaries gradually communicate due to the pressure reducing effect of the capillaries, so that the same function can be obtained. The subsequent removal of the flash gas is the same as in the first embodiment. According to this embodiment, the same effect as that of the first embodiment is exerted, and
It can be configured by general-purpose components that are sold at a low cost without using a special flow rate adjusting valve, and since it is a known refrigerant circuit, there is an advantage that the design is easy.

In each of the above embodiments, two indoor air conditioners are connected, but the number of indoor air conditioners is not limited to this, and three or more indoor air conditioners can be similarly implemented. Moreover, you may implement combining 1st Example and 2nd Example. Further, the branch unit does not necessarily have to be installed, and the branch unit can be eliminated and a flow rate adjusting valve or a solenoid valve and a bypass circuit as the second connecting means can be installed in each indoor air conditioner.

[0057]

As described above, according to the present invention, in an air conditioner in which an external air conditioner and a plurality of indoor air conditioners are connected in parallel, a gas pipe and a high pressure of a heat exchanger of the external air conditioner and each indoor air conditioner are provided. Since the gas pipe or the low-pressure gas pipe is connected by the first and second connecting means capable of adjusting the flow rate, respectively, when the heat exchanger of the outdoor air conditioner or the indoor air conditioner changes the operation mode,
By limiting the flow rate of the refrigerant at the time of switching the connection, the pressure of the refrigerant in the heat exchanger is reduced or increased to prevent abnormal noise.

Further, in particular, when the pressure difference before and after the connecting means becomes equal to or less than a predetermined value, the communication is fully opened so that the operation in a new mode is started with the minimum required time for switching. The effect is obtained. Therefore, it is possible to provide an air conditioner that can continue operation by quickly responding to changes in load without stopping the device and can supply air at any temperature from cooling to heating, and indoor air conditioning that does not require mode changes. It does not affect the opportunity.

Further, by opening the flow control valve of the external air conditioner or the indoor air conditioner to a predetermined opening for a predetermined time when starting the operation in the new mode, the flow control valve is accumulated near the expansion valve such as between the expansion valve and the flow control valve. Removes flash gas, so
The rising characteristic of the new operation mode is improved without impairing the controllability of the expansion valve and the flow rate adjusting valve.

[Brief description of drawings]

FIG. 1 is a diagram showing a refrigerant circuit according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a control device for an indoor air conditioner and an outdoor air conditioner in the embodiment.

FIG. 3 is a diagram showing a flow of a refrigerant during a cooling only operation.

FIG. 4 is a diagram showing a refrigerant flow during a heating only operation.

FIG. 5 is a flowchart showing a control flow when changing from cooling operation to heating operation in the indoor air conditioner.

FIG. 6 is a flowchart showing a control flow when the heating operation in the indoor air conditioner is changed to the cooling operation.

FIG. 7 is a flowchart showing the flow of control when changing from the condensation mode to the evaporation mode in the external air conditioner.

FIG. 8 is a flowchart showing a control flow when changing from the evaporation mode to the condensation mode in the external air conditioner.

FIG. 9 is a diagram showing a refrigerant circuit according to a second embodiment.

[Explanation of symbols]

1 Compressor 3 Accumulator 5A, 5B Flow rate adjusting valve 6 Heat exchanger 7 Expansion valve 8, 11A, 11B Pressure sensor 13A, 13B, 23A, 23B Flow rate adjusting valve 14A, 14B Flow rate adjusting valve 15A, 15B Expansion valve 16A, 16B Pressure sensor 18A, 18B Heat exchanger 21, 24A, 24B Blower 25 Flow rate adjusting valve 27 Liquid tank 30, 30 'Outer air conditioner 31 Air conditioner controller 32 Inverter circuit 34, 48, 39A, 39B, 41A, 41B Drive controller 37 Pressure Converter 40, 40 'Branch unit 43A, 43B Pressure converter 50A, 50B Indoor air conditioner 60A, 60B, 63A, 63B, 66A, 66B
Main solenoid valve 62A, 62B, 65A, 65B, 68A, 68B
Capillary 61A, 61B, 64A, 64B, 67A, 67B
Sub solenoid valves R1, R2, R3 Refrigerant piping

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuhiro Kojima 3-2-25 Minamihashimoto, Sagamihara City, Kanagawa Prefecture Inside the Toray Co., Ltd. Sagamihara Office (72) Inventor Takumasa Shinmachi 3-2-25 Minamihashimoto, Sagamihara City, Kanagawa Prefecture (72) Inventor Shuhei Yoshimoto 3-2-25 Minamihashimoto, Sagamihara City, Kanagawa Prefecture Inside the Topre Co., Ltd. Sagamihara Office

Claims (6)

[Claims] 1. An external regulator equipped with a heat exchanger, an expansion valve attached to the heat exchanger, and a flow rate adjusting valve provided in series with the expansion valve, and a heat exchanger and an attachment to the heat exchanger, respectively. Expansion valve, and a flow rate adjustment valve provided in series with the expansion valve,
It is composed of a plurality of indoor air conditioners connected in parallel to the external air conditioner by refrigerant pipes forming a liquid pipe of a refrigeration cycle, a high pressure gas pipe, and a low pressure gas pipe, and each indoor air conditioner individually performs cooling operation or heating. In an air conditioner selectively controlled for operation, a first connecting means capable of adjusting a flow rate between a gas pipe connected to a heat exchanger of the external controller and the high-pressure gas pipe or the low-pressure gas pipe. An air conditioner characterized in that the gas pipe connected to the heat exchanger of the indoor air conditioner and the high-pressure gas pipe or the low-pressure gas pipe are connected by second connecting means capable of adjusting the flow rate. . 2. When the heat exchanger of the external conditioner is changed from the evaporation mode to the condensation mode, the pressure in the heat exchanger of the external conditioner and the pressure of the high-pressure gas pipe are controlled by the first connecting means. Refrigerant is conducted from the high-pressure gas pipe while being restricted so as to be maintained at a predetermined pressure difference or more, and when the heat exchanger of the external controller changes from the condensation mode to the evaporation mode, The pressure and the pressure of the low-pressure gas pipe are made to pass through the low-pressure gas pipe while limiting so as to be maintained at a predetermined pressure difference or more, and when the pressure difference becomes smaller than a predetermined value, they are configured to be in full-open communication. When the heat exchanger of the indoor air conditioner is changed from a heating operation to a cooling operation, the pressure in the heat exchanger of the indoor air conditioner and the pressure of the low pressure gas pipe are equal to or more than a predetermined pressure difference. Refrigerant is conducted to the low-pressure gas pipe while being restricted to be held at When the heat exchanger of the indoor air conditioner is changed from the cooling operation to the heating operation, the pressure inside the heat exchanger of the indoor air conditioner and the pressure of the high-pressure gas pipe are limited to be maintained at a predetermined pressure difference or more. The air conditioner according to claim 1, wherein the refrigerant is made to flow from the high-pressure gas pipe, and when the pressure difference becomes smaller than a predetermined value, the refrigerant is fully opened. 3. The flow control valve of the external regulator is closed when the evaporation mode is changed to the condensation mode or when the condensation mode is changed to the evaporation mode, and after the limited conduction by the first connecting means. The air conditioner according to claim 2, wherein the gaseous refrigerant in the vicinity of the expansion valve of the external air conditioner is removed by opening it to a predetermined opening for a predetermined time. 4. The flow control valve of the indoor air conditioner is closed when the heating operation is changed to the cooling operation or when the cooling operation is changed to the heating operation, and after the limited conduction by the second connecting means. The air conditioner according to claim 2, wherein the gaseous refrigerant in the vicinity of the expansion valve of the indoor air conditioner is removed by being opened to a predetermined opening for a predetermined time. 5. The electronic device according to claim 1, wherein the first connecting means or the second connecting means is an electronic flow rate control valve whose opening is controlled. Air conditioner. 6. The first connecting means or the second connecting means comprises a main solenoid valve, and a bypass circuit in which a sub solenoid valve and a capillary are connected in series and are connected in parallel to the main solenoid valve, 5. The air conditioner according to claim 1, wherein the main solenoid valve is closed and a bypass circuit is opened to perform the limited conduction, and then the main solenoid valve is connected. apparatus.