JPH09229507A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable either a cooling operation or a heating operation to be carried out for every air-conditioned zone in a less-expensive manner. SOLUTION: A plurality of indoor air conditioners 50A to 50C are connected in parallel with an outdoor air conditioner 30 through a branch device 40, and blown air in the indoor air conditioners is guided into a plurality of air conditioned zones. The branch device is provided with a supercooling heat exchanger 12, and solenoid valves 13A to 13C, 23A to 23C capable of selecting a cooling operation and a heating operation through its changing-over operation. An outdoor air conditioner is provided with a supercooling heat exchanger 4, its liquid pipe side is provided with a flow rate adjusting valve 25 and an expansion valve 7. A liquid pipe side of an indoor air conditioner is provided with flow rate adjusting valves 14A to 14C and expansion valves 15A to 15C. An air supplying temperature is changed in response to an indoor air temperature in an air conditioned zone so as to control an indoor air temperature. With such an arrangement as above, it is possible to perform optionally a cooling operation or a heating operation in compliance with a respective request in each of the air conditioned zones and further an air supplying temperature is controlled, so that a comfortable air conditioning is carried out. In addition, when a cooling operation and a heating operation are carried out concurrently, thermal energy is transferred between the indoor air conditioners and a substantial energy saving can be attained.

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 Air conditioners such as an air handling unit and a fan coil using cold and hot water as a heat source are generally used for air conditioning of buildings and the like. In particular, the constant air volume single duct type air handling unit is an air conditioner that controls the indoor temperature of the air conditioning zone by sending a constant amount of air to the air conditioning zone and changing the air supply temperature, and is used in many buildings. There is. However, in recent years, water quality has been severely degraded, and this has caused many problems such as corrosion of pipes, and there has been a demand to reduce the use of water as much as possible. As a response to such a request, for example, a heat pump multi-system in which a refrigerant is used as a direct heat source has been proposed. On the other hand, air conditioning in recent years has been diversified, and cooling operations in summer and heating operations in winter are no longer simple. That is, in a building or the like, there are cases where it is desired to simultaneously perform cooling operation and heating operation in the air conditioning system depending on the season, the direction and position of the room, the load of the office automation equipment, and 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 the middle of spring and autumn, a heating operation is required in the morning and evening, and a cooling operation is required in the daytime in some cases. 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 although the condition to switch to the cooling operation is reached on the south side, the heating operation may still need to be maintained on the north side. . Further, in a place with a large load such as OA equipment, it may be necessary to perform cooling operation all day even in winter. Therefore, as a countermeasure against this, there is a case where a special air conditioning system having a cooling heat exchanger and a heating heat exchanger called a 4-pipe type air handling unit and capable of supplying air at any temperature from cooling to heating is adopted.

[0004]

However, the 4-pipe type air handling unit system has a drawback in that it has to have two heat sources, a cold heat source and a warm heat source, and the facility cost and the operating cost are high. Further, since the waste heats of the two heat sources are respectively discarded, it is against energy saving.
In addition, the heat pump multi-type, which can be operated at the same time as cooling and heating, requires an indoor unit to be installed in a living area, and its maintainability is extremely low. Further, since this is an indoor circulation type air conditioning system, there is a problem in that an external air treatment device must be newly installed for each indoor unit for the outdoor air treatment function, and high equipment cost is required.

Further, in the simultaneous cooling and heating operation, it is impossible to properly distribute the refrigerant between a plurality of indoor units of the same mode or between the indoor unit and the outdoor unit of the same mode, and the capacity control of the compressor is not sufficient. Therefore, the blowing temperature is also different for each indoor unit, so when the set temperature is reached, the function is stopped by closing the refrigerant control valve of the indoor unit, and it is not said that room temperature controllability is good. I want to.

Further, an outdoor unit and an indoor unit must be installed respectively for a plurality of air conditioning zones having different loads due to the direction and position of the air conditioning zone in the building, uneven distribution of OA equipment, and the like. The number of air conditioners increased,
Therefore, the installation space is increased. Further, in the simultaneous cooling and heating type heat pump multi system, the blast temperature cannot be controlled by simply controlling the capacity of the compressor. This is because in the simultaneous cooling / heating simultaneous operation heat pump multi system, the refrigerant piping distances from the outdoor unit to the plurality of indoor units are different, and the pressure loss is proportional to the square of the refrigerant flow velocity, so even if the compressor capacity control is performed. This is because the refrigerant pressure distribution reaching each indoor unit changes significantly and the refrigerant flow rate of each indoor unit also changes.

Further, the constant air volume single duct type air handling unit detects the room temperature in the air conditioning zone and controls the supply air temperature by the difference from the set temperature. For example, during cooling operation, step control is performed in which the supply air temperature is decreased by a certain amount when the room temperature is higher than the set temperature, and the supply air temperature is increased by a certain amount when the room temperature is low. However, if the difference is large, it takes a long time for the room temperature to reach the set temperature, and if the change amount of the supply air temperature is too large, cold draft occurs or the room temperature hunts. Furthermore, since the supply air temperature at startup is a preset temperature and does not take into consideration the load of the air conditioning zone, it will take some time to reach the set temperature when the load is large. There was a problem that it was not possible to meet the demand for a quick start such as in the morning.

Therefore, in view of the above-mentioned conventional problems, the present invention is an air conditioner equipped with an outdoor air conditioner and a plurality of indoor air conditioners, which requires a high load cost in each air conditioning zone without requiring a high equipment cost. Air conditioner that can be individually cooled or heated according to the
It is an object of the present invention to provide an air conditioner that is capable of individually changing the supply air temperature to an arbitrary temperature and is excellent in energy saving.

[0009]

Therefore, the present invention provides a heat exchanger, an expansion valve attached to the heat exchanger, a flow rate adjusting means provided in front of the expansion valve, and a flow rate adjusting means. An external air conditioner having first control means for controlling, a heat exchanger, an expansion valve attached to the heat exchanger, a flow rate adjusting means provided in front of the expansion valve, and the flow rate adjusting means And a second control means for controlling the temperature of each indoor air conditioner, which is composed of a plurality of indoor air conditioners connected in parallel to the air conditioner by refrigerant pipes forming a liquid pipe of the refrigeration cycle, a high pressure gas pipe, and a low pressure gas pipe. First, which is capable of guiding the supply air to each air conditioning zone and selectively connecting the gas pipe connected to the heat exchanger of the external air conditioner to the high pressure gas pipe or the low pressure gas pipe that goes to the heat exchanger of the external air conditioner. Gas connected to the switching means of No. 1 and the heat exchanger of each indoor air conditioner Has a second switching means capable of being selectively connected to the high-pressure gas pipe or the low-pressure gas pipe, and selectively controls each indoor air conditioner to perform a cooling operation or a heating operation individually, and a supply air temperature thereof. Is configured to control the indoor temperature of each air conditioning zone.

The second control means of the indoor air conditioner controls the flow rate of the indoor air conditioner so as to change the degree of supercooling of the refrigerant in the expansion valve of the indoor air conditioner according to the supply air temperature during the cooling operation. Controlling the adjusting means, and controlling the flow rate adjusting means of the indoor air conditioner so as to change the degree of supercooling of the refrigerant that has exited the heat exchanger of the indoor air conditioner during heating operation according to the supply air temperature. It is desirable to do. Further, the first control means of the external air conditioner is such that when the heat exchanger of the external air conditioner acts as a condenser, the degree of supercooling of the refrigerant exiting the heat exchanger of the external air conditioner is the load of the heat exchanger. The flow rate adjusting means of the external regulator is controlled so that the value becomes a value determined in accordance with the above, and when the heat exchanger of the external regulator acts as an evaporator, the excess of the refrigerant flowing in the expansion valve of the external regulator is exceeded. It is desirable to control the flow rate adjusting means of the external controller so that the cooling degree becomes a value determined according to the load of the heat exchanger of the external controller.

Further, in at least one of the indoor air conditioners, when the heat exchanger acts as an evaporator, between the liquid pipe toward the indoor air conditioner and the low pressure gas pipe toward the external air conditioner,
It is preferable to provide a first subcooling heat exchanger for exchanging heat between each other, and also a liquid pipe going to the heat exchanger of the external regulator when the heat exchanger of the external regulator acts as an evaporator. A second subcooling heat exchanger for exchanging heat between each other is preferably provided between the low pressure gas pipe and the low pressure gas pipe. Also, the supply temperature is
When the indoor air conditioner is started, it is set to a value determined by the indoor temperature and the set temperature of each air conditioning zone, and then changed based on the value determined by the set temperature, the indoor temperature and the change in the indoor temperature. Is desirable.

[0012]

The air is supplied from each indoor air conditioner to each air conditioning zone through the duct, and the indoor temperature of each air conditioning zone is adjusted by the change of the air supply temperature of each indoor air conditioner. In the outdoor air conditioner and the indoor air conditioner, the first and second control means control the degree of supercooling so as to reach the temperature to be supplied by using the flow rate adjusting valves arranged in front of the respective expansion valves, By selectively connecting the gas pipes of each indoor air conditioner and the heat exchanger of the external controller with the high-pressure gas pipes or the low-pressure gas pipes, any indoor air conditioner can be used in a form in which cooling operation and heating operation are simultaneously mixed. You can choose either. Further, during the simultaneous cooling and heating operation, heat energy is transferred between the indoor air conditioners, resulting in significant energy saving.

Further, the second control means of the indoor air conditioner is
By controlling the degree of supercooling of the refrigerant by the flow rate adjusting means so that the supply temperature is determined according to the room temperature,
Even if the supply air temperature changes, it does not interfere with other indoor air conditioners, and in each indoor air conditioner, the pressure of the refrigerant entering the expansion valve can be stably maintained, and air conditioning with stable supply air temperature can be performed. Be seen.

When the first supercooling heat exchanger is provided between the liquid pipes and the low pressure gas pipes which are directed to the plurality of indoor air conditioners, the control range of the flow rate by the flow rate adjusting means is expanded. Further, when a second supercooling heat exchanger is provided between the liquid pipe and the low-pressure gas pipe to the heat exchanger of the external pressure regulator, the degree of superheat of the gas refrigerant entering the compressor of the external pressure regulator should be increased. And the heating capacity is improved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the system configuration of the first embodiment of the present invention. In this embodiment, three indoor air conditioners 50A and 50B are provided for one outdoor air conditioner 30.
50C are connected in parallel via the branching unit 40. The air that has undergone heat exchange from each indoor air conditioner is in the duct 47.
Air conditioning zones ZA, ZB, ZC by A, 47B, 47C
Be led to. Each duct is branched appropriately according to the number of corresponding air conditioning zones, and is individually sent to the air conditioning zones. 45A, 45B and 45C are indoor temperature sensors, which are 49
A, 49B and 49C are indoor temperature setting devices, which are connected to indoor air conditioners 50A, 50B and 50C, respectively.

FIG. 2 shows the refrigerant circuit of this embodiment. The three indoor air conditioners 50A, 50B and 50C are branch units 40.
Through the refrigerant pipes R1, R2, and R3 that form a liquid pipe, a low-pressure gas pipe, and a high-pressure gas pipe, and are connected in parallel to the external conditioner 30. The external conditioner 30 includes the compressor 1 and the heat exchanger 6 with variable capacity. The pressure sensor 1 is installed on the discharge side and the suction side of the compressor 1, respectively.
1A and 11B are provided. A blower 21 is attached to the heat exchanger 6, and temperature sensors 10A and 10B are provided at both ends, respectively.

The external conditioner 30 further includes a subcooling heat exchanger 4
The electronic flow rate adjusting valve 25, the temperature sensor 9 for detecting the refrigerant temperature, the pressure sensor 8, and the electronic expansion valve 7 are installed in this order from the subcooling heat exchanger 4 side in the direction of the heat exchanger 6. ing. The other end of the supercooling heat exchanger 4 is connected to the refrigerant pipe R1 via the liquid tank 27. The refrigerant pipe (gas pipe) on the other end side of the heat exchanger 6 is connected to the inlet of the heat exchange passage of the supercooling heat exchanger 4 via the solenoid valve 5A, and is also connected to the refrigerant pipe R3 via the solenoid valve 5B. It is connected to the. The outlet of the heat exchange passage of the supercooling heat exchanger 4 is connected to the refrigerant pipe R2. 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.

The branch unit 40 includes the subcooling heat exchanger 12. The subcooling heat exchanger 12 is connected to the liquid tank 27 of the external conditioner 30 via the refrigerant pipe R1. In addition, the outlet of the subcooling heat exchanger 12 has indoor air conditioners 50A, 50B, 50
It is branched and connected to C. Furthermore, branch unit 4
0, solenoid valves 13A, 13B, 13C, 23A, 23
B, 23C are provided, and solenoid valves 13A, 13B, 13C
Enables the indoor air conditioners 50A, 50B, 50C to communicate with the other refrigerant pipe R2 system of the subcooling heat exchanger 12, and the solenoid valves 23A, 23B, 23C use the indoor air conditioners 50A, 50B, 50C as refrigerants. It is possible to communicate with the pipe R3.

The indoor air conditioner 50A includes a heat exchanger 18A,
It has a blower 24A attached thereto. Heat exchanger 18
One end of A is the subcooling heat exchanger 1 of the branch unit 40.
2 is connected to the R1 system, and the other end is connected to the solenoid valves 13A and 23A of the branch unit 40. The heat exchanger 18
In the R1 pipe on one end side of A, an electronic flow control valve 14A in order from the subcooling heat exchanger 12 side to the heat exchanger 18A,
Temperature sensor 17A for detecting refrigerant temperature, pressure sensor 1
6A, an electronic expansion valve 15A is provided.

The heat exchanger 18A has a temperature sensor 22 for detecting the supply air temperature and the return air temperature of the indoor air conditioner, respectively.
A and 26A are attached, and temperature sensors 19A and 20A for detecting the refrigerant temperature are provided at both ends. The air supplied by the heat exchanger 18A and blown by the blower 24A has a duct 47A as shown in FIG.
Leads to the air conditioning zone ZA. Indoor air conditioner 50B,
50C also has the same configuration as the indoor air conditioner 50A, and hereinafter, reference numerals B and C are attached respectively.

FIG. 3 shows a control device for the indoor air conditioner and the outdoor air conditioner. The control device is composed of a microcomputer and its peripheral devices for both the indoor air conditioner and the outdoor controller. The inverter 32 for the compressor 1 and the inverter 33 for the blower 21 of the external controller are connected to the external controller control unit 31. Further, as peripheral devices, the drive control unit 34 of the expansion valve 7, the drive control unit 48 of the flow adjustment valve 25, the drive control unit 35 of the solenoid valves 5A and 5B, and the temperature sensors 9 and 10.
Temperature transducers 36, pressure sensors 8, 1 for A, 10B
The pressure converter 37 for 1A and 11B is the external air conditioner controller 3
1 connected.

On the other hand, the control device for the indoor air conditioner 50A includes an indoor air conditioner control unit 51A and a supply air temperature setting unit 46A connected thereto. The indoor air conditioner control unit 51A includes, as peripheral devices, a drive control unit 39A for the expansion valve 15A, a drive control unit 41A for the flow rate adjusting valve 14A, and each temperature sensor 17.
Temperature transducer 42A for A, 19A, 20A, 22A and 26A, pressure transducer 4 for pressure sensor 16A
Drive controller 48 for 3A, solenoid valves 13A, 23A
A and a temperature converter 44A are connected. The temperature converter 44A includes a temperature sensor 45A that detects the indoor temperature of the air conditioning zone and a temperature holding unit 5 that holds the detected temperature.
2A is connected. The supply air temperature setting unit 46A calculates and holds the supply air temperature based on the set room temperature input from the room temperature setting device 49A. Indoor air conditioners 50B, 50C
The control device in (1) is also configured in the same manner, and the indoor air conditioner control units 51B and 51C, as well as the reference numbers B and C, respectively, are shown.

External air conditioner controller 31 and each indoor air conditioner controller 5
1A, 51B and 51C are connected by a communication means, and the external conditioner control unit 31 controls the indoor air conditioner control units 51A and 51B.
You can always know the situation of 51C. External conditioner control unit 3
Reference numeral 1 integrates the load amounts of the indoor air conditioners sent from the indoor air conditioner control units 51A, 51B, and 51C for each operation mode, and outputs a control signal corresponding to the load amount of the larger operation mode for the compressor 1. It is sent to the inverter 32. The inverter 32 drives the compressor 1 according to the control signal. In addition, the external air conditioner control unit 31 sets the heat exchanger 6 of the external air conditioner to be in the same mode as the operation mode in which the load amount of all the indoor air conditioners is smaller, that is, the load in the cooling operation is higher. The peripheral equipment is controlled so that the heat exchanger 6 of the external air conditioner 30 works as an evaporator when the load is small and as a condenser when the load for heating operation is smaller.

Indoor air conditioner control units 51A, 51B, 51C
Detects the indoor temperature of the air-conditioning zone from the temperature sensors 45A, 45B, 45C, and the respective temperature holding sections 52A, 5A
2B and 52C. Then, at startup, the supply air temperature setting units 46A, 46B, and 46C have the room temperature setting units 49A and 4A, 4B.
Based on the difference between the set room temperature input from 9B and 49C and the detected room temperature obtained by the temperature sensors 45A, 45B, and 45C, the supply air temperature is determined from the relationship table shown in FIG.
Hold. In FIG. 4, the supply air temperature that changes linearly around the detection room temperature (room temperature) according to the difference between the set room temperature and the detection room temperature is obtained.

Next, the return air temperature sensors 26A, 26B, 26
Temperature data detected by C and supply air temperature setting units 46A, 46
The difference with the temperature data of B and 46C is calculated, and each indoor air conditioner 50A, 50B, and 50C determines the operation mode of cooling operation or heating operation. And since the supply air temperature of the indoor air conditioner is affected by the return air temperature and humidity of the indoor air conditioner,
The load increase / decrease amount in consideration of them is added, and the load amount corresponding to the output of the compressor 1 is sent to the external air conditioner control unit 31 together with the operation mode of the indoor air conditioner.

From the start-up until the preset supply air temperature change time elapses, control is performed based on the initially determined supply air temperature. The supply air temperature change time is determined in consideration of the scale of the entire system and other conditions, but is normally set within a range of about 5 to 30 minutes from startup. The indoor air conditioner control units 51A, 51B, 51C detect the indoor temperature each time the supply air temperature change time elapses, and calculate the difference between the detected indoor temperature and the set indoor temperatures of the room temperature setters 49A, 49B, 49C. At the same time, it is compared with the temperatures of the room temperature holding units 52A, 52B, and 52C to determine whether the room temperature is rising or falling, or whether there is no change. Then, the change amount of the supply air temperature is determined according to the change state of the room temperature.

FIG. 5 is a graph used to determine the amount of change in the supply air temperature, and the relationship between the amount of change in the supply air temperature and the difference between the detected room temperature and the set room temperature is shown by a straight line. (A)
Is applied when the room temperature is increasing, (b) is applied when the room temperature is not changing, and (c) is applied when the room temperature is decreasing. In (a), a straight line is used as compared with (b). Is shifted in the decreasing direction, and the supply air temperature is lowered by a predetermined amount even if the difference between the detected indoor temperature and the set indoor temperature is zero.
Further, in (c), the straight line is shifted in the increasing direction as compared with (b), and the supply air temperature is increased by a predetermined amount even if the difference between the detected indoor temperature and the set indoor temperature is zero.

Indoor air conditioner control units 51A, 51B, 51C
The supply air temperature determined in this manner is used as the supply air temperature setting unit 46.
A, 46B and 46C are held. Further, the solenoid valves 5A and 5B, 13A and 23A, 13B and 23B, 13C and 23
C is controlled such that when one is open, the other is closed. However, when the indoor air conditioner does not need to be operated, both are closed.

Next, the operation of the above configuration will be described. FIG. 6 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 solenoid valve 5B
Is opened and the solenoid valve 5A is closed. In the branch unit, the solenoid valves 13A, 13B and 13C are controlled to be open and 23A, 23B and 23C are controlled to be closed. The heat exchanger 6 of the external air conditioner acts as a condenser, and the heat exchangers 18A, 18B, 18C of each indoor air conditioner act as evaporators.

That is, in the external conditioner 30, the high pressure gas refrigerant from the compressor 1 is supplied to the solenoid valve 5B as shown by the arrow.
And is liquefied in the heat exchanger 6. Then, after passing through the subcooling heat exchanger 4 and the liquid tank 27, the refrigerant pipe R1 enters the subcooling heat exchanger 12 of the branch unit 40. The refrigerant is heat-exchanged with the gas refrigerant discharged from the heat exchangers 18A, 18B, 18C of the indoor air conditioners 50A, 50B, 50C by the supercooling heat exchanger 12, and becomes a liquid refrigerant having an increased degree of supercooling.

Further, the refrigerant is branched by a branch pipe,
Each of the flow rate adjusting valves 14A, 14B, 14C enters in parallel and is subsequently decompressed by the expansion valves 15A, 15B, 15C,
It becomes a low temperature gas-liquid mixed state. Next, the refrigerant is the heat exchanger 1
Heat is exchanged with the return air in 8A, 18B, and 18C to become a gaseous refrigerant. Then, the solenoid valves 13A, 13B, 13
It returns to the subcooling heat exchanger 12 via C, and cools the liquid refrigerant flowing in from the external pressure regulator 30 through the refrigerant pipe R1. The refrigerant that has left the subcooling heat exchanger 12 returns to the compressor 1 of the external air conditioner 30 via the refrigerant pipe R2. Flow rate adjusting valves 14A, 14
B and 14C constitute the flow rate adjusting means of the indoor air conditioner of the invention, and the supercooling heat exchanger 12 constitutes the first supercooling heat exchanger of the invention.

During this time, the expansion valve 7, the flow rate adjusting valve 25, the blower 21, and the indoor air conditioners 50A, 50 of the external air conditioner 30
The flow rate control valves 14A, 14B, 14C for B and 50C and the expansion valves 15A, 15B, 15C are controlled as follows. First, the expansion valve 7 is held in the fully opened state by the external pressure control unit 31. Next, the external air conditioner control unit 31 detects the pressure of the refrigerant with the pressure sensor 8 and calculates the saturation temperature of the refrigerant entering the flow rate adjusting valve 25. Then, the flow rate adjusting valve 25 is controlled so that the difference from the temperature detected by the temperature sensor 9, that is, the degree of supercooling becomes a value obtained from the calculation of the relational expression of the load and the degree of supercooling of the external controller that is determined in advance. . The relational expression between the load of the external air conditioner and the supercooling degree level is not only calculated but also stored in the form of a graph showing the levels C1 to C10 as shown in FIG. 7, and can be read from this.

Further, a signal by, for example, PID control or step control is output to the blower inverter 33 so that the pressure detected by the discharge side pressure sensor 11A of the compressor 1 becomes a preset value, and the blower 21 Is driven to control the air volume.

On the other hand, the indoor air conditioner control units 51A, 51B,
In 51C, the supply air temperature detected by the temperature sensors 22A, 22B, and 22C is calculated in advance to obtain the supply air temperature setting units 46A and 4A.
The degree of supercooling required to reach the temperatures held in 6B and 46C is calculated. Next, the pressure sensors 16A, 16B,
The pressure of the refrigerant is detected by 16C, and each expansion valve 15A, 15
The saturation temperature of the refrigerant entering B and 15C is calculated, and the difference with the temperature detected by the temperature sensors 17A, 17B and 17C is calculated to obtain the actual degree of supercooling. Then, the flow rate adjusting valves 14A, 14B and 14C are controlled so that the required degree of supercooling is achieved. That is, the detected supply air temperature is the supply air temperature setting unit 46A,
When the temperature is higher than that held in 46B and 46C, the flow rate adjusting valves 14A and 14A are set to increase the degree of supercooling of the refrigerant.
B and 14C are controlled, and when the detected temperature is lower than the maintained temperature, the flow control valve 14 is set to reduce the degree of supercooling.
A, 14B, 14C will be controlled.

Further, temperature sensors 19A, 19B, 19
The expansion valve 15 is arranged so that the temperature difference between the refrigerant at the inlets and the outlets of the heat exchangers 18A, 18B, and 18C, that is, the degree of superheat is constant, depending on the detected temperatures of C, 20A, 20B, and 20C.
Control A, 15B, 15C. Here, if the loads on the indoor air conditioners 50A, 50B, and 50C are equal, the openings of the flow rate adjusting valves 14A, 14B, and 14C are the same. In this case, the refrigerant is evenly distributed from the branching unit 40 to the indoor air conditioners 50A, 50B, 50C, and the supply air temperatures are the same.

Here, for example, it is assumed that the load of the indoor air conditioner 50A is heavy and the supply air temperature is set low, and the load of the indoor air conditioners 50B and 50C is light and the supply air temperature is set high. Then, the indoor air conditioner control unit 51 of the indoor air conditioner 50A
A sends a signal to increase the load amount to the external conditioner control unit 31, and the indoor air conditioner control units 51B and 51C of the indoor air conditioners 50B and 50C should decrease the load amount to the external conditioner control unit 31. Send a signal. In response to this, the external conditioner control unit 31
Controls the total amount of load from each indoor air conditioner control unit by determining whether to increase or decrease the output of the compressor 1.

The indoor air conditioner control unit 51A is set to increase the degree of supercooling, and the indoor air conditioner control unit 51B,
51C is set to reduce the degree of supercooling, and the flow rate adjusting valves 14A, 14B, and 14C control the degree of opening so that the degree of supercooling is changed.

Here, the expansion valves 15A, 15B and 15C do not directly control the supply air temperature and the refrigerant flow rate, only by keeping the superheat degree of the heat exchangers 18A, 18B and 18C constant.
The expansion valves 15A, 15B, 15C are controlled by controlling the openings of the flow rate adjusting valves 14A, 14B, 14C so as to change the degree of supercooling of the refrigerant entering the expansion valves 15A, 15B, 15C.
The pressure at the inlet of the heat exchanger 18A, 18B, 1
Since the flow rate of the refrigerant flowing through 8C changes and the amount of heat exchange changes accordingly, the supply air temperature is controlled. FIG. 8 is a Mollier diagram of the refrigeration cycle showing the above control procedure. In the figure, (a) shows the pressure drop by the flow rate adjusting valves 14A, 14B, 14C, (b) shows the controlled supercooling degree, (c) shows the pressure drop by the expansion valves 15A, 15B, 15C,
(D) is a supercooling portion by the supercooling heat exchanger 12.

Since the branching unit 40 includes the subcooling heat exchanger 12, the flow rate adjusting valves 14A, 14B,
The degree of supercooling of the liquid refrigerant entering 14C can be increased, and even if the opening degree of the flow rate adjusting valve is narrowed down, the refrigerant does not start to expand, so the control range of the flow rate adjusting valve is expanded.

The subcooling heat exchanger 12 also serves to completely gasify the returned refrigerant. That is, when the air volume of all the indoor air conditioners 50A, 50B, and 50C suddenly decreases due to some problem, the expansion valves 15A and 15B,
The control speed of 15C cannot keep up with the heat exchangers 18A, 18A.
Even if the liquid refrigerant that has not completely evaporated in B and 18C flows, the subcooling heat exchanger 12 functions as a temporary heat storage device, so that the liquid compression phenomenon of the liquid refrigerant entering the compressor 1 can be prevented. Similarly, since the degree of superheat of the gas refrigerant of the compressor 1 can be secured by the subcooling heat exchanger 12, the expansion valves 15A, 15B, 15 of the indoor air conditioners 50A, 50B, 50C are
The degree of superheat due to C can be set to be small, and heat exchangers 18A, 1
The utilization efficiency of 8B and 18C can be improved.

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 in heating operation, the solenoid valve 5A is open and the solenoid valve 5B is closed in the external air conditioner, and the solenoid valves 23A, 23 in the branch unit.
B and 23C are opened, and solenoid valves 13A, 13B and 1
3C is controlled to be in a closed state. The heat exchanger 6 of the external air conditioner is an evaporator, the heat exchangers 18A and 18B of the indoor air conditioners,
18C 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 through the refrigerant pipe R3. The refrigerant is branched here, and the solenoid valve 23A,
Each indoor air conditioner 50A, 50 through 23B, 23C
B and 50C heat exchangers 18A, 18B and 18C are liquefied. After that, it passes through the subcooling heat exchanger 12 of the branch unit, returns to the external regulator 30 through the refrigerant pipe R1, and enters the subcooling heat exchanger 4 through the liquid tank 27. The refrigerant is heat-exchanged with the gas refrigerant from the heat exchanger 6 in the supercooling heat exchanger 4 to become a liquid refrigerant having an increased degree of supercooling.

Further, the refrigerant is decompressed by the expansion valve 7,
A low-temperature gas-liquid mixed state is established and the heat exchanger 6 is entered. The refrigerant is heat-exchanged with the outdoor air in the heat exchanger 6 to become a gas, and advances to the supercooling heat exchanger 4 via the solenoid valve 5A. Here, while cooling the liquid refrigerant coming from the liquid tank 27 as described above,
It becomes a gas refrigerant with increased superheat. After that, the refrigerant returns to the compressor 1 through the accumulator 3. Here, the subcooling heat exchanger 4 constitutes the second subcooling heat exchanger of the invention.

During this time, the expansion valves 15A, 15B, 1
5C, flow rate adjusting valve 25, blower 21, flow rate adjusting valve 14
Control of A, 14B, 14C and the expansion valve 7 is performed as follows. First, each indoor air conditioner control unit 51A, 51B,
The expansion valve 15A, 15B, 15C is held fully open by 51C. Next, the external air conditioner control unit 31 detects the pressure of the refrigerant with the pressure sensor 8 and calculates the saturation temperature of the refrigerant entering the expansion valve 7. Then, the flow rate adjusting valve 25 is controlled so that the difference from the temperature detected by the temperature sensor 9, that is, the degree of supercooling becomes the degree of supercooling obtained from the relational expression between the load of the external regulator and the degree of supercooling. The above relational expression gives the degree of supercooling indicated by levels D1 to D10 according to the load as shown in FIG. Further, a signal by, for example, PID control or step control is output to the blower inverter 33 so that the pressure detected by the pressure sensor 11B of the compressor 1 becomes a preset value, and the blower 21 is driven to change the air volume. Control.

On the other hand, the indoor air conditioner control units 51A, 51B,
In 51C, the supply air temperature detected by the temperature sensor, 22A, 22B, 22C is calculated in advance, and the supply air temperature setting unit 46A,
The degree of supercooling required to reach the temperatures held in 46B and 46C is calculated. Next, the pressure sensors 16A, 16
The pressure of the refrigerant is detected by B and 16C, and each flow rate adjustment valve 14
Calculate the saturation temperature of the refrigerant entering A, 14B, 14C,
The difference between this saturation temperature and the temperatures detected by the temperature sensors 17A, 17B and 17C is calculated to obtain the actual degree of supercooling.
That is, the detected supply air temperature is the supply air temperature setting units 46A and 4A.
When the temperature is higher than that held in 6B and 46C, the flow control valves 14A, 14B and 14 are set to increase the degree of supercooling.
C is controlled, and when the detected temperature is lower than the maintained temperature, the flow control valves 14A and 14A, 14
B and 14C are controlled.

Further, in the external conditioner control section 31, the temperature sensor 1
Based on the temperatures detected by 0A and 10B, the expansion valve 7 is controlled so that the degree of superheat of the heat exchanger 6 is kept constant, as in the indoor air conditioner during the cooling operation. Here, each indoor air conditioner 50
If the loads of A, 50B, and 50C are equal, the openings of the flow rate adjusting valves 14A, 14B, and 14C are the same.
In this case, the refrigerant flows from the branch unit 40 to each indoor air conditioner 5
0A, 50B, 50C are evenly distributed, and the supply air temperatures are the same.

Here, for example, it is assumed that the load of the indoor air conditioner 50A is heavy and the supply air temperature is set high, and the load of the indoor air conditioners 50B and 50C is light and the supply air temperature is set low. Then, the indoor air conditioner control unit 51 of the indoor air conditioner 50A
A sends a signal to increase the load amount to the external conditioner control unit 31, and the indoor air conditioner control units 51B and 51C of the indoor air conditioners 50B and 50C should decrease the load amount to the external conditioner control unit 31. Send a signal. In response to this, the external conditioner control unit 31
Controls the total amount of load from each indoor air conditioner control unit by determining whether to increase or decrease the output of the compressor 1.

The indoor air conditioner controller 51A is set to reduce the degree of supercooling, and the indoor air conditioner controller 51B,
51C is set to increase the degree of supercooling, and the flow rate adjusting valves 14A, 14B, and 14C control the degree of opening so that the degree of supercooling is changed. FIG. 11 is a Mollier diagram of the refrigeration cycle showing the above control procedure. In the figure,
(A) is a pressure drop by the expansion valves 15A, 15B, 15C, (b) is a subcooling part by the subcooling heat exchanger 12,
(C) shows the amount of pressure drop by the flow control valves 14A, 14B, 14C, and (d) is the controlled degree of supercooling.

In this heating operation, since the degree of supercooling is controlled by the flow rate adjusting valve, the degree of supercooling becomes large and a large amount of liquid refrigerant accumulates in the heat exchangers 18A, 18B, 18C, and the entire refrigeration cycle lacks refrigerant. The occurrence of a trouble phenomenon that causes Furthermore, the subcooling heat exchanger 4 of the external air conditioner
Helps to completely liquefy the return refrigerant. That is, when the air volume of the indoor air conditioners 50A, 50B, and 50C is suddenly reduced due to some problem, the flow rate control valves 14A and 1A
Even if the control speeds of 4B and 14C do not catch up and the uncondensed gas refrigerant flows to the external controller 30, the subcooling heat exchanger 4 functions as a temporary heat storage device, so that the gas refrigerant enters the expansion valve 7. It is possible to prevent deterioration of controllability due to. In addition, the external conditioner 30
Even if the amount of air is temporarily reduced by the control of the blower 21 and the unevaporated liquid refrigerant flows into the compressor 1, it can be similarly prevented. Similarly, since the degree of superheat of the gas refrigerant entering the compressor 1 can be increased by the subcooling heat exchanger 4, the discharge temperature of the compressor 1 is increased and the heating capacity is improved accordingly.

Next, the operation of the simultaneous cooling / heating main cooling operation in which the cooling operation and the heating operation are performed in parallel and the load of the indoor air conditioner is larger in the cooling operation than in the heating operation will be described. FIG.
2 shows the flow of the refrigerant at this time. Here, for example, as an example, the indoor air conditioner 50A is in the heating operation, and the indoor air conditioner 5 is
It is assumed that 0B and 50C are in cooling operation. First,
The solenoid valve 5B is open and the solenoid valve 5A is closed in the external conditioner, and the solenoid valves 23A, 13B, 13C are in the branch unit.
Is controlled to be open, and the solenoid valves 13A, 23B, and 23C are controlled to be closed. Heat exchanger 6 of the outside air conditioner and indoor air conditioner 1
8A acts as a condenser, and the heat exchangers 18B and 18C of the indoor air conditioner act as evaporators.

In the external air conditioner 30, the high pressure gas refrigerant from the compressor 1 enters the heat exchanger 6 through the solenoid valve 5B and is liquefied there. The refrigerant discharged from the heat exchanger 6 passes through the supercooling heat exchanger 4 and the liquid tank 27 and enters the supercooling heat exchanger 12 of the branch unit 40 through the refrigerant pipe R1. The high pressure gas refrigerant from the compressor 1 also enters the branching unit 40 via the refrigerant pipe R3. The refrigerant through the refrigerant pipe R3 is the solenoid valve 23.
After passing through A, it enters the heat exchanger 18A of the indoor air conditioner 50A and is liquefied there.

The refrigerant that has entered the subcooling heat exchanger 12 of the branching unit via the refrigerant pipe R1 is supplied to the indoor air conditioners 50B, 50.
The liquid refrigerant is heat-exchanged with the gas refrigerant coming out of the C heat exchangers 18B, 18C to become a liquid refrigerant having an increased degree of supercooling. This refrigerant once merges with the liquid refrigerant coming from the heat exchanger 18A of the indoor air conditioner 50A through the branch pipe, and then the indoor air conditioners 50B, 50
Enter C in parallel. Here, the flow rate adjusting valve 14
B, 14C, followed by decompression by the expansion valves 15B, 15C into a low temperature gas-liquid mixed state, and the heat exchangers 18B, 1C.
Enter 8C.

The refrigerant is heat-exchanged with the return air in the heat exchangers 18B and 18C to become a gaseous refrigerant. Then, it returns to the supercooling heat exchanger 12 via the solenoid valves 13B and 13C, and cools the liquid refrigerant that comes in from the external controller 30 via the refrigerant pipe R1. The refrigerant exiting the supercooling heat exchanger 12 is the refrigerant pipe R2.
And returns to the compressor 1 of the external conditioner 30.

During this time, the expansion valve 7, the flow rate adjusting valve 25, the blower 21, the flow rate adjusting valve 14A of the indoor air conditioner 50A, the expansion valve 15A, the indoor air conditioners 50B, 50C of the external air conditioner 30 during this period.
The flow rate adjusting valves 14B and 14C and the expansion valves 15B and 15C are controlled as follows. First, the external conditioner control unit 31
The expansion valve 7 is held in the fully open state. Flow rate adjusting valve 25
Is controlled so that the degree of supercooling calculated by the pressure sensor 8 and the temperature sensor 9 becomes the degree of supercooling calculated in FIG. 7, similarly to the control during the cooling operation.

As for the blower 21, similarly to the control of the cooling only operation, the inverter 33 controls the pressure detected by the discharge side pressure sensor 11A to a preset value.
Is driven to control the air volume. On the other hand, in the indoor air conditioner control unit 51A of the indoor air conditioner 50A, the expansion valve 15A
Hold it fully open. Then, the flow rate adjusting valve 14A is controlled so as to have a necessary degree of supercooling based on the set supply air temperature, similarly to the control of the flow rate adjusting valve of the indoor air conditioner during the heating only operation.

In addition, in the indoor air conditioner control units 51B and 51C of the indoor air conditioners 50B and 50C, the expansion valves 15B and 15C are included.
However, similar to the control of the expansion valve of the indoor air conditioner during the cooling only operation, it is controlled so that the degree of superheat becomes constant, and the flow control valve 14
Similarly, B and 14C are controlled so as to obtain the required degree of supercooling based on the set supply air temperature. In addition,
When the load of each indoor air conditioner changes, the description is omitted because it is the same as that of the indoor air conditioner in the same operation mode in the cooling only operation or the heating only operation. FIG. 13 is a Mollier diagram of the refrigeration cycle showing the above control procedure. In the figure, (a) is the degree of supercooling controlled by the flow rate adjusting valve of the external air conditioner or the indoor air conditioner 50A, (b) is the pressure drop by the flow rate adjusting valve of the external air conditioner or the indoor air conditioner 50A, (c). Is a supercooling part by the supercooling heat exchanger 12, (d) is a pressure drop by the flow rate adjusting valve of the indoor air conditioner 50B or 50C,
(E) is the degree of supercooling controlled by the flow control valve of the indoor air conditioner 50B or 50C, and (f) is the pressure drop by the expansion valve of the indoor air conditioner 50B or 50C.

Next, the operation of the cooling / heating simultaneous heating main operation in which the load of the indoor air conditioner is larger in the heating operation than in the cooling operation in the cooling / heating simultaneous operation will be described with reference to FIG. 14 showing the flow of the refrigerant. Here, for example, it is assumed that the indoor air conditioner 50A is in cooling operation and the indoor air conditioners 50B and 50C are in heating operation. First, in the external regulator, the solenoid valve 5A is open and the solenoid valve 5B is closed. In the branch unit, the solenoid valves 13A, 23B and 23C are open, and the solenoid valve 23A,
Control is performed so that 13B and 13C are closed. The heat exchanger 6 of the external air conditioner and the heat exchanger 18A of the indoor air conditioner are evaporators,
The heat exchangers 18B and 18C of the indoor air conditioner act as condensers.

In this operation, the high-pressure gas refrigerant from the compressor 1 of the external air conditioner 30 enters the branch unit 40 via the refrigerant pipe R3. Here, the refrigerant passes through the solenoid valves 23B and 23C, and then the heat exchangers 18B and 1B of the indoor air conditioners 50B and 50C.
It enters 8C and is liquefied. The refrigerant discharged from the heat exchangers 18B and 18C merges in the branch pipe of the branch unit 40, part of which flows to the indoor air conditioner 50A, and the rest of the refrigerant flows from the subcooling heat exchanger 12 and the refrigerant pipe R1 to the liquid of the external air conditioner. It enters the tank 27 and then the supercooling heat exchanger 4.

In the external air conditioner, the refrigerant is the subcooling heat exchanger 4
At this time, heat exchange is performed with the gas refrigerant from the heat exchanger 6, and the liquid refrigerant is increased in supercooling. Then, the refrigerant is decompressed by the expansion valve 7 into a low-temperature gas-liquid mixed state and enters the heat exchanger 6. The refrigerant that has been heat-exchanged with the outdoor air in the heat exchanger 6 and has become a gas passes through the subcooling heat exchanger 4 through the solenoid valve 5A and cools the liquid refrigerant that has come from the liquid tank 27 as described above. , Becomes a gas refrigerant with increased superheat.

On the other hand, the refrigerant entering the indoor air conditioner 50A is
The pressure is reduced by the expansion valve 15A and a low temperature gas-liquid mixed state is achieved.
Next, heat is exchanged with the return air in the heat exchanger 18A to become a gaseous refrigerant. After that, the refrigerant pipe R2 is passed through the solenoid valve 13A.
Head towards the outboard modulator 30. The refrigerant merges with the refrigerant that has left the subcooling heat exchanger 4 in the external conditioner 30, and returns to the compressor 1 via the accumulator 3.

During this period, the expansion valve 7, the flow rate adjusting valve 25, the blower 21, the flow rate adjusting valve 14A of the indoor air conditioner 50A, the expansion valve 15A, the indoor air conditioners 50B, 50C of the external air conditioner 30.
The flow rate adjusting valves 14B and 14C and the expansion valves 15B and 15C are controlled as follows. First, the external conditioner control unit 31
Controls the expansion valve 7 so that the degree of superheat becomes constant, similar to the control during the heating only operation. Similarly, the flow rate adjusting valve 25 is controlled to a value obtained from the relationship between the supercooling degree level and the external regulator load shown in FIG. 10. Also, the blower 21
With respect to, as in the control during the heating only operation, the blower inverter 33 is driven so that the pressure detected by the pressure sensor 11B reaches a preset value, and air volume control is performed.

Indoor air conditioner controller 51 of indoor air conditioner 50A
The control by A is performed by the indoor air conditioner 50 of the simultaneous cooling and heating main operation.
Since it is the same as the control of B and 50C, it is omitted. Also, the indoor air conditioner control units 51B, 5C of the indoor air conditioners 50B, 50C.
50A of indoor air conditioner at the time of main operation of simultaneous cooling and heating with 1C control
Is the same as

Next, for example, the indoor air conditioner 50A is operated for heating,
When the indoor air conditioners 50B and 50C are in the cooling operation and the cooling load and the heating load are the same, it is not necessary to operate the heat exchanger 6 of the external conditioner 30 as a condenser or an evaporator with respect to the difference between the loads. The flow rate adjusting valve 25 is closed and the blower 21 is also stopped. Then, all the refrigerant that has flowed through the indoor air conditioner 50A flows through the indoor air conditioners 50B and 50C that are parallel to each other, and the amount of heat is balanced.

The flow of control in the above-mentioned external air conditioner controller and indoor air conditioner controller is briefly shown in FIGS. 15 and 16. That is, in the external air conditioner control unit, as shown in FIG. 15, first, in step 101, the indoor air conditioner control unit 5
Information on operating conditions such as the load amount of the indoor air conditioner from 1A to 51C is input, and in step 102, these are integrated for each operating mode. Then, in step 103, the cumulative load amounts for each mode are compared, and when the cooling load is large, step 104 is performed, and when the heating load is large, step 113 is performed.
When both loads are the same, the routine proceeds to step 124.

When the cooling load is large, first step 1
At 04, a control signal corresponding to the load amount of the cooling load is sent to the inverter 32 to drive the compressor 1, and at step 105, the heat exchanger 6 is set to a mode of working as a condenser. In the next step 106, the heat exchanger load amount is obtained as the difference between the cooling load and the heating load,
In step 107, the target degree of supercooling is obtained by calculation or graph reading.

In step 108, the actual degree of supercooling is obtained from the difference between the saturation temperature of the refrigerant based on the value detected by the pressure sensor 8 and the temperature detected by the temperature sensor 9. Then, in step 109, the flow rate adjusting valve 25 is controlled so that the controlled supercooling degree and the actual supercooling degree match. After that, in step 110, the discharge pressure of the compressor 1 is detected by the pressure sensor 11A, and in step 111, the inverter 33 is driven so that the discharge pressure becomes a preset value, and the air volume of the blower 21 is controlled. Then, the process returns to step 101.

Next, when the heating load is large, at step 113, the control signal corresponding to the load amount of the heating load is sent to the inverter 32 to drive the compressor 1, and at step 114, at the heat exchanger. The mode in which 6 operates as an evaporator is set. In the next step 115, the heat exchanger load amount is obtained as the difference between the heating load and the cooling load, and in step 116 the target degree of supercooling is obtained by calculation or graph reading.

In step 117, the actual degree of supercooling is obtained from the difference between the saturation temperature of the refrigerant based on the value detected by the pressure sensor 8 and the temperature detected by the temperature sensor 9. Then, in step 118, the flow rate adjusting valve 25 is controlled so that the controlled supercooling degree and the actual supercooling degree match. Subsequently, in step 119, the degree of superheat of the heat exchanger 6 is obtained from the temperatures detected by the temperature sensors 10A and 10B, and step 120
The expansion valve 7 is controlled so as to keep this constant. After this, in step 121, the suction pressure of the compressor 1 is detected by the pressure sensor 11B, and step 12
In 2, the air flow rate of the blower 21 is controlled so that this pressure becomes a preset value. Then, the process returns to step 101.

When the cooling load and the heating load are the same, the flow rate adjusting valve 25 is closed in step 124, and the blower 21 is stopped in step 125.

On the other hand, the individual indoor air conditioner control units are shown in FIG.
6, as shown in FIG. 17, the blower 24 is first started in step 201. Next, at step 202, the temperature sensor 45 detects the indoor temperature of the air conditioning zone and the temperature is held in the temperature holding unit 52. Then, in step 203,
The set room temperature is input from the room temperature setting device 49. Next, at step 204, the supply air temperature at startup is calculated. Further, in step 205, the return air temperature of the indoor air conditioner is detected by the temperature sensor 26, and in step 206, the supply air temperature and the return air temperature set by the calculation are compared to determine whether to perform the cooling operation or the heating operation. Determine the mode.

In the case of the cooling operation mode, step 20
In step 7, first, the solenoid valve is switched to the cooling mode, in step 208, the actual supply air temperature is detected by the temperature sensor 22, and the supply air temperature (detection temperature) detected in step 209 and the set supply air temperature (set temperature) are detected. ) Are compared, and if the detected temperature is low, go to Step 210, and if it is high, Step 21.
1; if the same, proceed to step 212. Then, in step 210, the current degree of supercooling is set to be small, in step 211, the degree of supercooling is set to be large, the present degree of supercooling is detected in step 212, and the degree of supercooling set in step 213 is set. The flow rate adjusting valve 14 is controlled so that the flow rate is adjusted to 0. Further, in step 214, information on the current operating state of the indoor air conditioner is sent to the external controller.

Next, at step 215, the temperature sensor 1
The superheat degree is detected by 9 and 20, and the expansion valve 15 is controlled in step 216 based on the detected superheat degree. Next, step 21
At 7, it is checked whether the supply air temperature has changed. If the supply air temperature change time has not elapsed, the process returns to step 207, and if the set supply air temperature change time has already elapsed, the process proceeds to step 218. Step 2
At 18, the indoor temperature is detected by the temperature sensor 45, and at step 219, the direction of change of the indoor temperature is calculated by comparing with the previously detected temperature. Then, in step 220, the change amount of the supply air temperature is calculated, the supply air temperature is updated, and then the process returns to step 205.

On the other hand, in the heating mode, step 221
In step 22, switch the solenoid valve to the heating mode.
2, the actual supply air temperature is detected, and in step 223, the detected supply air temperature is compared with the set supply air temperature. If the detected temperature is low, the operation proceeds to step 224, and if it is high, the operation proceeds to step 22.
5 and to step 226 if they are the same. Then, in step 224, the current degree of supercooling is set to be small, and in step 225, the degree of supercooling is set to be large, and then the routine proceeds to step 226. In step 226, the current degree of supercooling is detected, and in step 227, the flow rate adjusting valve is controlled. Next, in step 228, the information on the operating state of the indoor air conditioner is sent to the external controller.

Thereafter, in step 229, it is checked whether or not the supply air temperature changing time has elapsed. Step 22 if the supply air temperature change time has not elapsed yet
The process returns to step 1, and if the time has passed, the process proceeds to step 230. Further, in step 230, the room temperature is detected, and in step 23
In step 1, the change direction of the indoor temperature is calculated by comparing with the previously detected temperature. Then, in step 232, the change amount of the supply air temperature is calculated, the supply air temperature is updated, and then the process returns to step 205.

The following briefly summarizes the present embodiment described above. First, in a heat pump type air conditioner that is connected in parallel to multiple indoor air conditioners from an external air conditioner via a branching unit, the air blow of the indoor air conditioners is guided to multiple air conditioning zones by ducts and air is supplied to each air conditioning zone. The temperature can be changed, the branch unit is equipped with a supercooling heat exchanger, and a solenoid valve that can select cooling operation and heating operation by switching between them is provided. Was equipped with a flow control valve and an expansion valve. A flow control valve and an expansion valve are installed on the liquid pipe side of the heat exchanger of the indoor air conditioner, and the supercooling degree is controlled by the flow control valve so that the supply air temperature changes according to the load of each indoor air conditioner. During the cooling operation, the expansion valve is controlled so that the degree of superheat of the heat exchanger is constant. On the other hand, in the external air conditioner, the flow rate control valve is controlled so that the degree of supercooling corresponds to the load of the external air conditioner, and when the heat exchanger is in the condensation mode, the expansion valve is fully opened, and in the evaporation mode. Is controlled so that the degree of superheat of the heat exchanger is constant. Then, the supply air temperature of the indoor air conditioner starts with the one determined from the set room temperature and the detected room temperature at startup, and after the elapse of a predetermined time, the supply air temperature is set based on the set room temperature, the detected room temperature and the change amount thereof. Are to be changed sequentially. As a result, there is an effect that the cooling operation and the heating operation can be arbitrarily executed and the supply air temperature can be freely changed according to the individual requirements of each air conditioning zone. In addition, the indoor temperature of each air conditioning zone can be arbitrarily controlled by the change of the supply air temperature without being affected by the load condition of other indoor air conditioners, so that a comfortable environment can be obtained.

Therefore, it is not necessary to install an air conditioner in a large number of individual air conditioning zones, and only a simple duct connection is required, thus improving maintainability. Further, during cooling operation, since the degree of supercooling of the refrigerant entering the flow rate adjusting valve of the indoor air conditioner is increased by the supercooling heat exchanger 12, the adjustment range of the flow rate adjusting valve can be expanded and a stable refrigeration cycle can be obtained. To be Furthermore, when the supply air volume of the indoor air conditioner suddenly decreases during the cooling operation, the subcooling heat exchanger 12 acts as a temporary heat storage device, and the liquid compression phenomenon in which the liquid refrigerant enters the compressor 1 of the external air conditioner is prevented. Even when the supply air volume suddenly decreases during the heating operation, the subcooling heat exchanger 4 of the external air conditioner acts as a temporary heat storage device to promote the reliable liquefaction of the refrigerant and the expansion valve 7
The controllability is prevented from decreasing.

The indoor air conditioners 50A, 50B, 50
Even if the installation location of C is different and there is a difference in the pipe length from the external air conditioner 30, the refrigerant state between the expansion valve and the flow rate adjustment valve of each indoor air conditioner can be made the same, so the pipe pressure loss during installation work. The same air conditioning capacity can be obtained without taking into consideration.

In the embodiment, the air that has undergone heat exchange in each indoor air conditioner is guided to each air conditioning zone by a duct. However, the present invention is not limited to this. For example, a ceiling or an underfloor in a building is used as a supply chamber. The same can be applied to the case of a ductless system that guides air supply. Further, in this embodiment, the relational table shown in FIG. 4 is used to determine the supply air temperature at startup based on the difference between the set room temperature and the detected room temperature. When the temperature difference is within a predetermined range with 0 in between, the room temperature (detection room temperature) is kept as it is, and when the difference exceeds the predetermined range, the value is adjusted with respect to the room temperature. You can set

FIG. 19 shows a second embodiment of the present invention.
In this embodiment, the branch circuit is eliminated from the refrigerant circuit of the first embodiment, and a subcooling heat exchanger that was in the branch unit is provided for each indoor air conditioner. That is, the refrigerant pipe R extending from the external conditioner 30
1 ', R2', R3 'are branched and each indoor air conditioner 50
A ', 50B', 50C 'are connected in parallel. Then, in each indoor air conditioner, the refrigerant pipe R1 ′ passes through the supercooling heat exchangers 12A, 12B, 12C, and then is connected to the flow rate adjusting valves 14A, 14B, 14C. In addition, the refrigerant pipe R2 'is the subcooling heat exchanger 12A, 12B, 12C.
Into the other passage of the solenoid valve 13A ', 13B', 13
The heat exchangers 18A, 18B and 18C are connected to the gas pipe side via C '. Further, the refrigerant pipe R3 'is connected to the heat exchanger 18 via the solenoid valves 23A', 23B ', 23C'.
It is connected to A, 18B, and 18C gas pipes.

Then, the solenoid valves 13A 'and 23A', 13
Similar to the first embodiment, B ′ and 23B ′ and 13C ′ and 23C ′ are controlled so that when one is in the open state, the other is in the closed state. 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 that in the first embodiment, so the description of the operation will be omitted.

According to this embodiment, the same effect as that of the first embodiment is obtained, and since the subcooling heat exchanger is provided separately for each indoor air conditioner, all the refrigerant flowing to the expansion valve is It is possible to increase the degree of supercooling by passing through the subcooling heat exchanger of No. 3, and there is an advantage that a supercooling heat exchanger that is easy to handle, small, and inexpensive can be used.

In the above embodiment, three indoor air conditioners are connected, but the number of indoor air conditioners is not limited to this, and two or four or more indoor air conditioners can be similarly used. It is possible, and if there is an indoor air conditioner that does not supply air, it is possible to fully close the flow rate control valve and not operate it.
It is also possible to provide a plurality of branch units and connect a plurality of indoor air conditioners to each of the branch units. Furthermore, the first embodiment and the second embodiment may be combined.

[0083]

As described above, the present invention relates to an air conditioner in which a plurality of indoor air conditioners are connected in parallel to an outside air conditioner.
By selectively connecting the gas pipes of each indoor air conditioner and the heat exchanger of the external air conditioner to the high pressure gas pipes or the low pressure gas pipes, it becomes possible to select cooling operation and heating operation for each indoor air conditioner. The air supply of the indoor air conditioner is guided to multiple air conditioning zones by ducts, and the indoor temperature of each air conditioning zone is adjusted by changing the air supply temperature for each air conditioning zone. It has the effect of providing the environment. Further, since it is not necessary to individually install a large number of air conditioners, maintainability is improved, and during simultaneous cooling / heating operation, thermal energy is transferred between the indoor air conditioners, so that a large energy saving effect is obtained.

Further, by controlling the flow rate adjusting means so that the degree of supercooling of the refrigerant becomes a value determined in accordance with the supply air temperature of the indoor air conditioner, the air conditioner capable of supplying air at an arbitrary supply air temperature. Is done. In addition, the expansion valve of the indoor air conditioner is not affected by other indoor air conditioners, so there is no difference in capacity depending on the installation location of each indoor air conditioner, and there is no need to correct the capacity when designing the air conditioner. The effect is that the construction can be simplified.

By providing the first supercooling heat exchanger between the liquid pipes and the low pressure gas pipes which are directed to the plurality of indoor air conditioners, the control range of the flow rate by the flow rate adjusting means is expanded. Thus, for example, even if the supply air volume of the indoor air conditioner is suddenly reduced, the returning refrigerant is surely gasified by the heat storage function of the subcooling heat exchanger, and damage to the compressor is prevented. Also,
Second between the low pressure gas pipe and the liquid pipe that goes to the heat exchanger of the external air conditioner
By installing the subcooling heat exchanger of the above, it is possible to increase the degree of superheat of the gas refrigerant entering the compressor of the external air conditioner, improve the heating capacity, and when the supply air temperature of the indoor air conditioner is suddenly changed. Also, the reliable liquefaction of the return refrigerant can be promoted by the heat storage function of the supercooling heat exchanger.

Further, the air supply temperature of the indoor air conditioner is started at the air supply temperature determined by the room temperature detected in the air conditioning zone and the set temperature at the time of start-up, and the air supply temperature is changed between the room temperature and the room temperature. By supplying the air at the temperature determined by the change and the set temperature, the indoor temperature can be quickly set to the set temperature, and comfortable air conditioning can be obtained without causing hunting.

[Brief description of drawings]

FIG. 1 is a diagram showing a system configuration according to a first embodiment of the present invention.

FIG. 2 is a refrigerant circuit diagram in the embodiment.

FIG. 3 is a diagram showing a control device in an indoor air conditioner and an outdoor air conditioner.

FIG. 4 is a graph showing the relationship between the detected indoor temperature, the set indoor temperature, and the supply air temperature at startup.

FIG. 5 is a graph showing the relationship between the detected indoor temperature, the set indoor temperature, and the supply air temperature during operation.

FIG. 6 is a diagram showing a refrigerant flow during a cooling only operation.

FIG. 7 is a graph showing the relationship between the load of the external air conditioner and the degree of supercooling during the cooling only operation.

FIG. 8 is a Mollier diagram of a refrigeration cycle showing a control procedure during a cooling only operation.

FIG. 9 is a diagram showing a refrigerant flow of a refrigerant during a heating only operation.

FIG. 10 is a graph showing the relationship between the load of the external air conditioner and the degree of supercooling during the heating only operation.

FIG. 11 is a Mollier diagram of the refrigeration cycle showing the control procedure during the heating only operation.

FIG. 12 is a diagram showing the flow of a refrigerant during the main cooling / heating simultaneous cooling main operation.

FIG. 13 is a Mollier diagram of a refrigerating cycle showing a control procedure during simultaneous cooling / heating main operation.

FIG. 14 is a diagram showing a refrigerant flow in a main operation for simultaneous heating / cooling heating.

FIG. 15 is a flowchart showing a control flow in an external conditioner control section.

FIG. 16 is a flowchart showing a control flow in an indoor air conditioner control unit.

FIG. 17 is a flowchart showing a control flow in an indoor air conditioner control unit.

FIG. 18 is a graph showing a modified example of the relationship between the detected indoor temperature at startup, the set indoor temperature, and the supply air temperature.

FIG. 19 is a system configuration diagram showing a second embodiment.

[Explanation of symbols]

1 Compressor 3 Accumulator 4 Supercooling heat exchanger 5A, 5B Solenoid valve 6 Heat exchanger 7 Expansion valve 8 Pressure sensor 9 Temperature sensor 10A, 10B Temperature sensor 11A, 11B Pressure sensor 12 Supercooling heat exchanger 13A, 13B, 13C, 23A, 23B, 23C
Solenoid valves 13A ', 13B', 13C ', 23A', 23B ',
23C 'Solenoid valve 14A, 14B, 14C Flow rate adjusting valve 15A, 15B, 15C Expansion valve 16A, 16B, 16C Pressure sensor 17A, 17B, 17C Temperature sensor 18A, 18B, 18C Heat exchanger 19A, 19B, 19C, 20A, 20B , 20C
Temperature sensor 21 Blower 22A, 22B, 22C, 26A, 26B, 26C
Temperature sensor 24A, 24B, 24C Blower 25 Flow rate control valve 27 Liquid tank 30 External regulator 31 External regulator controller 34, 35, 48 Drive controller 36 Temperature converter 37 Pressure transducer 39A, 39B, 39C, 41A, 41B , 41C
Drive control unit 40 Branch unit 42A, 42B, 42C, 44A, 44B, 44C
Temperature converter 43A, 43B, 43C Pressure converter 45A, 45B, 45C Temperature sensor 46A, 46B, 46C Air supply temperature setting part 47A, 47B, 47C Duct 48A, 48B, 48C Drive control part 49A, 49B, 49C Room temperature setting device 50A, 50B, 50C, 50A ', 50B', 50
C'Indoor air conditioner 51A, 51B, 51C Indoor air conditioner control unit 52A, 52B, 52C Temperature holding unit R1, R2, R3, R1 ', R2', R3 'Refrigerant pipe ZA, ZB, ZC Air conditioning zone

Front page continuation (72) Inventor Yasuhiro Kojima 3-2-25 Minamihashimoto, Sagamihara-shi, Kanagawa Topre Co., Ltd.Sagamihara Works (72) Inventor Takumasa Shinmachi 3-2-25, Minamihashimoto, Sagamihara-shi, Kanagawa Topre Co., Ltd. Sagamihara Works (72) Inventor Shuhei Yoshimoto 3-2-25 Minamihashimoto, Sagamihara City, Kanagawa Prefecture Topre Sagamihara Works

Claims (6)

[Claims] 1. An external conditioner comprising: a heat exchanger, an expansion valve attached to the heat exchanger, a flow rate adjusting means provided in front of the expansion valve, and a first control means for controlling the flow rate adjusting means. And a heat exchanger, an expansion valve attached to the heat exchanger, a flow rate adjusting means provided in front of the expansion valve, and a second control means for controlling the flow rate adjusting means. Of a plurality of indoor air conditioners connected in parallel to the external air conditioner by a refrigerant pipe forming a liquid pipe, a high pressure gas pipe and a low pressure gas pipe, and guides the air supply of each indoor air conditioner to each air conditioning zone. A first switching means capable of selectively connecting a gas pipe connected to the heat exchanger of the external air conditioner to a high pressure gas pipe or a low pressure gas pipe directed to the heat exchanger of the external air conditioner, and each indoor air conditioner The high pressure gas pipe or the low pressure gas pipe connected to the heat exchanger of A second switching means that can be selectively connected to the pipe is provided, and each indoor air conditioner is selectively controlled to an air-cooling operation or a heating operation individually, and each air-conditioner is changed by changing its supply air temperature. An air conditioner configured to control the indoor temperature of a zone. 2. The second control means of the indoor air conditioner so as to change the degree of supercooling of the refrigerant contained in the expansion valve of the indoor air conditioner according to the supply air temperature during the cooling operation. And controlling the flow rate adjusting means of the indoor air conditioner so as to change the degree of supercooling of the refrigerant exiting the heat exchanger of the indoor air conditioner during heating operation in accordance with the supply air temperature. The air conditioner according to claim 1, wherein the air conditioner is a thing. 3. The first control means of the external air conditioner is configured such that when the heat exchanger of the external air conditioner acts as a condenser, the degree of supercooling of the refrigerant leaving the heat exchanger of the external air conditioner is equal to that of the heat exchanger. The flow rate adjusting means of the external controller is controlled so that the value is determined according to the load of the exchanger, and when the heat exchanger of the external controller acts as an evaporator, the expansion valve of the external controller is 3. The flow control means of the external air conditioner is controlled so that the degree of supercooling of the existing refrigerant becomes a value determined according to the load of the heat exchanger of the external air conditioner. The air conditioner described. 4. In at least one of the indoor air conditioners, between the liquid pipe to the indoor air conditioner and the low pressure gas pipe to the external air conditioner when the heat exchanger acts as an evaporator,
The air conditioner according to claim 1, 2 or 3, wherein a first subcooling heat exchanger that exchanges heat with each other is provided. 5. A second heat exchanger between the liquid pipe and the low-pressure gas pipe, which goes to the heat exchanger of the external regulator when the heat exchanger of the external regulator acts as an evaporator. 3. A subcooling heat exchanger according to claim 1 or 2,
The air conditioner according to 3 or 4. 6. The supply air temperature is set to a value determined by the indoor temperature and the set temperature of each air conditioning zone when the indoor air conditioner is activated, and thereafter, the set temperature, the indoor temperature and the change in the indoor temperature are set. It is changed based on the value determined by
4. The air conditioner according to 4 or 5.