JP4779791B2 - Air conditioner - Google Patents

Description

  The present invention relates to an air conditioner including a plurality of outdoor units.

Conventionally, an air conditioner includes an indoor unit, an outdoor unit that adjusts a refrigerant that performs air conditioning in the indoor unit, a refrigerant piping system that connects each outdoor unit and each indoor unit, and a control unit that controls the operation of the outdoor unit. It has. The outdoor unit includes a compressor that compresses the refrigerant, a gas engine that drives the compressor, and an outdoor heat exchanger. According to this, the compressor is driven by driving the gas engine to compress the refrigerant. Then, in the indoor heat exchanger and the outdoor heat exchanger provided in the refrigerant circuit, the refrigerant condensing action and the refrigerant evaporating action are performed to perform air conditioning.
JP 2004-347306 A

By the way, in recent years, an air conditioner including a plurality of outdoor units has been developed. According to this, it is possible to cope with an increase in the air conditioning load of the indoor unit. Furthermore, since a plurality of outdoor units are driven in response to a request for an air conditioning load of the indoor unit, an efficient operation region can be used, and the efficiency of the entire system of the air conditioner can be improved. In the above-described air conditioner, since a plurality of outdoor units are connected by a common refrigerant piping system, various factors (for example, avoidance control that reduces the engine speed of any one of the outdoor units) are performed. Sometimes, the refrigerant flow rate is unbalanced in a plurality of outdoor units, for example, when the function of the fan is degraded. In this case, there is a limit in stabilizing the system of the air conditioner.

  This invention is made | formed in view of the above-mentioned actual condition, and makes it a subject to provide the air conditioning apparatus advantageous to stabilization of a system.

An air conditioner according to aspect 1 includes a plurality or a single indoor unit that performs air conditioning, a plurality of outdoor units that supply refrigerant to the indoor unit, a refrigerant piping system that connects each outdoor unit and each indoor unit, and an outdoor unit And a control unit for controlling the operation of
Each outdoor unit, Oite evaporated a compressor having a discharge port for discharging the suction port and compressed refrigerant suck the refrigerant, and a driving source for driving the compressor, an outdoor heat exchanger connected to the compressor, during the heating operation of the indoor unit between the control valve opening which serves as an expansion valve at a variable heating operation to control the flow rate of refrigerant flowing from the indoor unit to the outdoor heat exchanger serving as a vessel, a suction port and the outdoor heat exchanger of the compressor An accumulator for returning the refrigerant from the outdoor heat exchanger during heating operation and sending the refrigerant to the intake port of the compressor by driving the compressor, and an accumulator provided between the accumulator and the intake port of the compressor. Detects the intake temperature of refrigerant sucked into the intake port of the compressor That is provided with a temperature sensor,
The control unit
The degree of suction superheat at which the suction temperature of the refrigerant sucked into the suction port of the compressor of each outdoor unit is determined based on the suction temperature detected by the temperature sensor provided between the accumulator and the suction port of the compressor Computing means;
When the intake superheat levels of the compressor intake temperatures of multiple outdoor units differ, the opening of the control valve is increased for an outdoor unit with a relatively high intake superheat level, and the outdoor unit with a relatively low intake superheat level is controlled. An opening degree increasing / decreasing means for decreasing the opening degree of the valve is provided.

According to the present invention, the temperature sensor is provided between the accumulator and the suction port of the compressor. The temperature sensor detects the suction temperature of the refrigerant sucked into the compressor suction port from the accumulator by driving the compressor. The intake superheat degree calculating means obtains the intake superheat degree of the intake temperature of the compressor of each outdoor unit based on the intake temperature detected by a temperature sensor provided between the accumulator and the intake port of the compressor. When the intake superheat degree of the suction temperature of the compressors of a plurality of outdoor units is different, the opening degree increasing / decreasing means has a relative refrigerant flow rate relative to an outdoor unit having a relatively high suction superheat degree compared to other outdoor units. Therefore, the opening of the control valve is increased, and the flow rate of the refrigerant flowing into the outdoor heat exchanger serving as an evaporator during the heating operation of the indoor unit is increased.

  On the other hand, the opening degree increase / decrease means is estimated that the refrigerant flow rate is relatively excessive for the outdoor unit having a relatively low suction superheat degree as compared with other outdoor units. And the flow rate of the refrigerant flowing into the outdoor heat exchanger serving as an evaporator during the heating operation of the indoor unit is reduced. Thereby, the opening degree of the control valve in the plurality of outdoor units is optimized during the heating operation of the indoor unit. As a result, excess and deficiency of the refrigerant flow rate in the plurality of outdoor units is reduced, and consequently the refrigerant flow rate in the plurality of outdoor units is optimized.

  Here, according to a preferred aspect of the present invention, the outdoor units are the first outdoor unit and the second outdoor unit, and the control unit controls the command opening degree θ1 of the control valve of the first outdoor unit, the control of the second outdoor unit. The valve command opening θ2 is determined based on the following equation.

(I) Command opening degree θ1 of the control valve of the first outdoor unit =
α1 × current control valve opening degree of first outdoor unit × {suction superheat degree of first outdoor unit / (suction superheat degree of first outdoor unit + suction superheat degree of second outdoor unit)} × 2
(Ii) Command opening degree θ2 of the control valve of the second outdoor unit =
α2 × current control valve opening degree of the second outdoor unit × {suction superheat degree of the second outdoor unit / (suction superheat degree of the first outdoor unit + suction superheat degree of the second outdoor unit)} × 2
Here, α1 and α2 are adjustment values. When the first outdoor unit and the second outdoor unit have the same capacity, α1 and α2 can be set to 1.0, respectively.

  According to the present invention, preferably, a temperature sensor that detects the suction temperature of the refrigerant sucked into the suction port of the compressor and a pressure sensor that detects the pressure of the refrigerant sucked into the suction port of the compressor are provided.

  Here, when the suction temperature of the refrigerant sucked into the suction port of the compressor is T1 (° C.) and the low pressure saturation temperature is T2 (° C.), the degree of superheat (superheat) (° C.) = T1 (° C.) − T2 (° C.).

According to the air conditioner of the present invention, during the heating operation of the indoor unit , excessive and insufficient refrigerant flow rates in the plurality of outdoor units are reduced, and the opening degree of the control valve in the outdoor unit is optimized. The system is stabilized.

  Hereinafter, embodiments of the present invention will be described. This is applied to an engine-driven air conditioner. FIG. 1 schematically shows an overall configuration diagram. FIG. 2 shows a system piping diagram. The air conditioner includes a plurality of indoor units 1A and 1B that perform indoor air conditioning, a plurality of outdoor units 2A and 2B that adjust refrigerant that performs air conditioning indoors, the outdoor units 2A and 2B, and the indoor units 1A and 1B. And a refrigerant piping system 3 that connects the two. The refrigerant piping system 3 is shared by the outdoor units 2A and 2B and the indoor units 1A and 1B. The control unit 4 has a first control unit 4A mounted on the outdoor unit 2A and a second control unit 4B mounted on the outdoor unit 2B. The first control unit 4A has a storage element 40A (see FIG. 6).

  The outdoor units 2A and 2B basically have the same constituent elements and are set to exhibit the same ability. For the outdoor units 2A and 2B, the outdoor unit 2A is set as a master unit, and the outdoor unit 2B is set as a slave unit. The first control unit 4A mounted on the outdoor unit 2A that is the master unit outputs a command to the second control unit 4B mounted on the outdoor unit 2B that is the slave unit via the communication line 100. The second control unit 4B mounted on the outdoor unit 2B that is the slave unit transmits the operation status of the outdoor unit 2B to the first control unit 4A mounted on the outdoor unit 2A that is the base unit via the communication line 100. Feedback.

  As shown in FIG. 2, the indoor units 1A and 1B are disposed indoors, and for the air conditioning, an indoor heat exchanger 10 that performs heat exchange between the refrigerant and the indoor air, and an expansion valve 11 that expands the refrigerant, As a basic element. The number of indoor units may be any number, but it is represented as indoor units 1A and 1B.

  The outdoor units 2A and 2B are arranged outside the room. The outdoor units 2A and 2B are driven and driven by the engine 20 (drive source) formed by a gas engine, an accumulator 21 that stores the refrigerant in a state where the gaseous refrigerant and the liquid refrigerant are separated, and the gas engine 20. Accordingly, a plurality of compressors 22 (compression units) that suck and compress the gaseous refrigerant of the accumulator 21 and an outdoor heat exchanger 23 that performs heat exchange of the refrigerant for air conditioning are provided as basic elements. Here, when it is necessary to distinguish clearly, the engine of the outdoor unit 2A may be referred to as the engine 20A, and the engine of the outdoor unit 2B may be referred to as the engine 20B. The number of engine times of the engine 20A is detected by the first sensor 24A (detection means). The number of engine times of the engine 20B is detected by the second sensor 24B (detection means).

  In the indoor units 1A and 1B, the compressor 22 is interlocked by the engine 20 via a power transmission member such as a timing belt. Therefore, the gas engine 20 functions as a drive source for the compressor 22. The compressor 22 has a suction port 22i that sucks gaseous refrigerant from the accumulator 21 into a compression chamber, and a discharge port 22p that discharges high-pressure gaseous refrigerant compressed in the compression chamber.

  As will be described later, a control valve (expansion valve) is provided upstream of the outdoor heat exchanger 23 in the return direction (arrow K1 direction) in which the refrigerant returns from the indoor units 1A, 1B to the outdoor units 2A, 2B during heating operation. A functioning electronic regulating valve 25 and a check valve 26 are arranged in parallel. The check valve 26 allows the refrigerant to flow from the outdoor heat exchanger 23 of the outdoor units 2A and 2B to the indoor units 1A and 1B, but the outdoor heat exchanger 23 of the outdoor units 2A and 2B from the indoor units 1A and 1B. Block the flow of refrigerant to the. The opening of the electronic adjustment valve 25 can be adjusted by electrical control. The electronic adjustment valve 25 includes a drive unit such as a motor or a solenoid, and a valve unit whose opening degree is variable by driving the drive unit, and the flow rate can be varied. Since the control unit 4 controls the drive unit of the main adjustment valve 25, the opening degree of the main adjustment valve 25 can be controlled.

(During heating operation)
First, the case where the room is heated will be described. During the heating operation, both the outdoor units 2A and 2B are driven, and both basically perform the same function. When the gas engine 20 is driven by the fuel gas, the compressor 22 is driven, and the gaseous refrigerant in the accumulator 21 is sucked in from the suction port 21 i of the accumulator 21 and the suction port 22 i of the compressor 22 through the flow path, and the compression chamber of the compressor 22 is driven. It is compressed with. The gaseous refrigerant compressed to high temperature and high pressure is discharged from the discharge port 22p of the compressor 22 and reaches the flow path 3a and the oil separator 27. As described above, oil is separated from the refrigerant in the oil separator 27. The gaseous high-temperature and high-pressure refrigerant from which the oil has been separated passes through the third port 28t of the four-way valve 28, passes through the flow path 3c, the ball valve 291 and the flow paths 3d and 3e, and reaches the indoor heat exchanger 10. Heat is exchanged with indoor air in the indoor heat exchanger 10 to condense (liquefy). Since the condensation heat is released into the room, the room is heated. Therefore, the indoor heat exchanger 10 functions as a condenser during the heating operation of the indoor units 1A and 1B.

  And the refrigerant | coolant which progressed liquefaction through the indoor heat exchanger 10 will be in a liquid phase state or a gas-liquid two-phase state, will reach the expansion valve 11, will be expanded by the expansion valve 11 of indoor unit 1A, 1B, and will become a low voltage | pressure. Furthermore, the low-pressure refrigerant flows through the flow paths 3f and 3g, the ball valve 292, and the flow path 3h in the direction of the arrow K1 (the direction of returning from the indoor units 1A and 1B to the outdoor units 2A and 2B during heating operation). , Reaches the electronic adjustment valve 25, flows through the electronic adjustment valve 25, and reaches the outdoor heat exchanger 23. The refrigerant evaporates in the outdoor heat exchanger 23 and exchanges heat with the outside air. Therefore, the outdoor heat exchanger 23 functions as an evaporator during the heating operation of the indoor units 1A and 1B. Here, during the heating operation of the indoor units 1A and 1B, the electronic adjustment valve 25 functions as an expansion valve, and expands the refrigerant. Here, the opening degree of the electronic adjustment valve 25 can be adjusted. Therefore, during the heating operation of the indoor units 1A and 1B, the flow rate of the refrigerant returning from the indoor units 1A and 1B to the outdoor heat exchanger 23 of the outdoor units 2A and 2B can be adjusted according to the opening degree of the electronic adjustment valve 25. .

  Further, the refrigerant returns to the return port 21r of the accumulator 21 through the flow path 3k, the first port 28f, the second port 28s of the four-way valve 28, and the flow path 3m. The returned refrigerant is stored in a state where it is separated into a liquid refrigerant and a gaseous refrigerant by the accumulator 21. A first fan 51 for blowing air toward the outdoor heat exchanger 23 and a second fan 52 for blowing air toward the indoor heat exchanger 10 are provided.

  Conventionally, an orifice or a capillary tube is attached to a portion where the electronic adjustment valve 25 is provided. However, since the orifice and the capillary tube are not variable in cross-sectional area, they are fixed. It is necessary to set the flow path cross-sectional area of the orifice or capillary tube for each model, and there is a trouble of attaching the orifice or capillary tube having a different flow path cross-sectional area for each model. In this embodiment, since the electronic adjustment valve 25 having a variable flow path cross-sectional area is provided as a control valve, the above-described troublesomeness is reduced.

  According to the present embodiment, at the time of the heating operation described above, the control unit 4A reads the air conditioning load requested from the indoor units 1A and 1B. From the sum of the requested air conditioning loads, the total amount of refrigerant flow required for the current air conditioning is calculated. From the total amount of the refrigerant flow rate, the opening degree of the electronic adjustment valve 25 that supplies the refrigerant necessary for the outdoor heat exchanger 23 that functions as an evaporator during the heating operation is obtained by calculation. Depending on the opening, the outdoor units 2A and 2B are attempted to be operated in the same operating condition.

  However, the refrigerant flow may be biased due to various factors in the outdoor units 2A and 2B and the indoor units 1A and 1B. Factors include fan failure, execution of control to prevent an excessive increase in engine water temperature, and the like.

  In order to correct the deviation of the refrigerant flow rate, the control unit 4A performs electronic control so that the suction superheat degree is constant in each of the outdoor units 2A and 2B with respect to the refrigerant amount flowing into the outdoor heat exchanger functioning as an evaporator during the heating operation. The opening degree of the regulating valve 25 is controlled. This eliminates the refrigerant flow rate imbalance in each of the outdoor units 2A and 2B without changing the overall refrigerant flow rate.

  In the following, further explanation will be given regarding the elimination of imbalance. The control unit 4A obtains the suction superheat degree of the suction temperature of the compressor 22 of each outdoor unit 2A, 2B. Specifically, in both the outdoor units 2A and 2B, a temperature sensor 80 that detects the suction temperature of the refrigerant sucked into the suction port 22i of the compressor 22 is provided in the compressor 22. In both the outdoor units 2 </ b> A and 2 </ b> B, a pressure sensor 83 that detects the pressure of the refrigerant sucked into the suction port 22 i of the compressor 22 is provided between the accumulator 21 and the compressor 22.

  When the suction temperature of the refrigerant sucked into the suction port 22i of the compressor 22 is T1 (° C.) and the low pressure saturation temperature is T2 (° C.), the suction superheat degree (° C.) is obtained by T1 (° C.) − T2 (° C.). It is done. T1 (° C.) is detected by the temperature sensor 80. T2 (° C.) is obtained based on the pressure sensor 83 as follows.

  A method for obtaining T2 (° C.) will be described. FIG. 5 shows a Mollier diagram of the refrigerant. The horizontal axis shows the enthalpy of the refrigerant. The vertical axis represents the refrigerant pressure (absolute pressure). Line A1 indicates a saturated liquid line. Line A2 represents a saturated vapor line. Line A3 indicates the dryness of the refrigerant. The region on the left side of the line A1 indicates the liquid phase region of the refrigerant. A region on the right side of the line A2 indicates a gas phase region of the refrigerant. A region surrounded by the lines A1 and A2 indicates a gas-liquid two-phase region. The pressure obtained by the pressure sensor 83 is converted into an absolute pressure and collated with the vertical axis (absolute pressure) of the Mollier diagram of FIG. When the intersection of the virtual horizontal line HA and the line A3 passing through the absolute pressure is obtained, this intersection corresponds to T2 (° C.).

  For example, when the absolute pressure is 5 atmospheres, the intersection (= T2) is −15 ° C. when the intersection of the virtual horizontal line HA passing through 5 atmospheres and the line A3 is obtained. Accordingly, the degree of superheat of suction = T1 (° C.) − T2 (° C.) = − 5 ° C .− (− 15 ° C.) = 20 ° C. In this way, for both the outdoor units 2A and 2B, the refrigerant suction superheat degree (° C.) is obtained for the suction port 22i of the compressor 22.

  In this way, the control unit 4A determines the suction superheat degree of the suction temperature of the compressor 22 for both of the plurality of outdoor units 2A and 2B.

  According to the present embodiment, when the suction temperatures of the compressors 22 of the plurality of outdoor units 2A, 2B are different, the control unit 4A has a relatively high suction superheat degree among the plurality of outdoor units 2A, 2B. For the outdoor unit, control is performed to increase the opening of the electronic adjustment valve 25 (expansion valve) and increase the flow rate of refrigerant flowing into the outdoor heat exchanger 23 (functioning as an evaporator during heating operation). Further, among the plurality of outdoor units 2A and 2B, for the outdoor unit having a relatively low suction superheat degree, the opening degree of the electronic adjustment valve 25 (expansion valve) is decreased, and the outdoor heat exchanger 23 (the evaporator during the heating operation) is reduced. As a function) is performed to reduce the flow rate of the refrigerant. As a result, during the heating operation of the indoor units 1A and 1B, the excess or deficiency of the refrigerant in the plurality of outdoor units 2A and 2B is reduced, and the opening degree of the electronic adjustment valve 25 in both the outdoor units 2A and 2B is optimized. . As a result, the system is stabilized.

  FIG. 4 shows an example of a flowchart of the suction superheat degree control process executed by the control unit 4A. The flowchart is not limited to this. First, in the suction superheat degree control process, the temperature sensor 80 and the pressure sensor 83 are read for the outdoor units 2A and 2B (step S2). Next, for the outdoor units 2A and 2B, T1 (° C.) is obtained as the suction temperature of the refrigerant sucked into the suction port 22i of the compressor 22 (step S4). A low-pressure saturation temperature T2 (° C.) of the refrigerant is obtained (step S6). The suction superheat degree (° C.) is obtained for the outdoor units 2A and 2B (step S8). Suction superheat degree (° C.) = T1 (° C.) − T2 (° C.) Step S8 functions as a suction superheat degree calculation means.

  Next, the difference between the suction superheat degree of the outdoor unit 2A and the suction superheat degree of the outdoor unit 2B is obtained (step S10). It is determined whether the difference is greater than a predetermined value ε (step S12). If the difference is smaller than the predetermined value ε, the process returns to the main routine.

If the difference is larger than the predetermined value ε, the command opening degree θ1 of the electronic adjustment valve 25 of the outdoor unit 2A is obtained based on the following one formula (step S14). Further, the command opening degree θ2 of the electronic adjustment valve 25 of the outdoor unit 2B is obtained based on the two formulas (step S16). Next, the command opening θ1 is output to the electronic adjustment valve 25 of the outdoor unit 2A, and the command opening θ2 is output to the electronic adjustment valve 25 of the outdoor unit 2B (step S18). It waits for a predetermined time until the opening degree of the electronic adjustment valve 25 is stabilized (step S20).
(Formula 1) Command opening θ1 = (α1 × current opening of electronic control valve 25 of outdoor unit 2A × intake superheat degree of outdoor unit 2A) / {(intake superheat degree of outdoor unit 2A + outdoor unit 2B Inhalation superheat) x 2}
(Equation 2)... Command opening .theta.2 = (. Alpha.2.times.current opening of electronic regulating valve 25 of outdoor unit 2B.times.intake superheat degree of outdoor unit 2B) / {(intake superheat degree of outdoor unit 2A + outdoor unit 2B. Inhalation superheat) x 2}
Here, since the outdoor units 2A and 1B have the same function, α1 and α2 are each 1. In steps S14, S16, and S18 described above, when the suction superheat degrees of the suction temperatures of the compressors 22 of the plurality of outdoor units 2A and 2B are different, the opening degree of the control valve 25 is set for the outdoor unit having a relatively high suction superheat degree. It functions as an opening degree increasing / decreasing means that increases and decreases the opening degree of the control valve 25 for the outdoor unit having a relatively low suction superheat degree.

(When cooling indoor units 1A and 1B)
Next, the case where the indoor unit 1A, 1B performs a cooling operation in the room will be described. When the gas engine 20 is driven by the fuel gas, the compressor 22 is driven, and the gaseous refrigerant in the accumulator 21 is sucked from the suction port 21 i of the accumulator 21 and the suction port 22 i of the compressor 22 and compressed in the compression chamber of the compressor 22. . The gaseous refrigerant compressed to high temperature and high pressure is discharged from the discharge port 22 i of the compressor 22 and reaches the flow path 3 a and the oil separator 27. Oil is separated from the refrigerant in the oil separator 27. The high-temperature and high-pressure refrigerant from which the oil has been separated passes through the flow path 3b, the first port 28f of the four-way valve 28 as a flow path switching valve, and the flow path 3k, and reaches the outdoor heat exchanger 23. The high-temperature and high-pressure refrigerant exchanges heat with the outside air in the outdoor heat exchanger 23 and is cooled and liquefied. The liquefied refrigerant (liquid phase state or gas-liquid two-phase state) reaches the expansion valve 11 via the check valve 26, the flow path 3h, the ball valve 292, the flow paths 3g, and 3f. It expands to a low temperature. During the cooling operation, the electronic regulating valve 25 is generally fully closed, but may be opened.

  Thus, the refrigerant having a low temperature in the outdoor heat exchanger 23 passes through the flow paths 3g and 3f, is expanded by the expansion valve 11 to become a low temperature and a low pressure, and further reaches the indoor heat exchanger 10 to the indoor heat exchanger 10. In this way, heat is exchanged with room air to cool the room. Further, the refrigerant returns to the return port 21r of the accumulator 21 through the flow path 3e, the ball valve 291, the flow path 3c, the third port 28t of the four-way valve 28, the second port 28s of the four-way valve 28, and the flow path 3m. The refrigerant returned to the accumulator 21 is accommodated in a state where it is separated into a liquid refrigerant and a gaseous refrigerant by the accumulator 21.

  During the cooling operation, the outdoor units 2A and 2B basically perform the same function. However, the refrigerant conveyance amount in the outdoor unit 2A can be controlled by controlling the opening degree of the electronic adjustment valve 25 of the outdoor units 2A and 2B as necessary. Moreover, the refrigerant | coolant conveyance amount in the outdoor unit 2B is controllable by controlling the opening degree of the electronic adjustment valve 25 of the outdoor unit 2B.

(Other embodiments)
FIG. 7 shows another embodiment. As shown in FIG. 7, there are three outdoor units 2A, 2B, and 2C. The outdoor units 2A, 2B, and 2C have control units 4A, 4B, and 4C, respectively. The outdoor unit 2A is a master unit, and the outdoor units 2B and 2C are slave units. There are three indoor units 1A, 1B, and 1C, but the number of indoor units is not limited to this.

  The control unit 4A sets the command opening θ1 of the control valve of the first outdoor unit 2A, the command opening θ2 of the control valve of the second outdoor unit 2B, and the command opening θ3 of the control valve of the third outdoor unit 2C as follows: Can be determined based on.

(I) Command opening degree θ1 of the control valve of the first outdoor unit 2A =
α1 × current control valve opening degree of first outdoor unit 2A × {intake superheat degree of first outdoor unit 2A / (intake superheat degree of first outdoor unit 2A + intake superheat degree of second outdoor unit 2B + third Outdoor unit 2C suction superheat degree)} × 3
(Ii) Command opening degree θ2 of the control valve of the second outdoor unit 2B =
α2 × current control valve opening degree of second outdoor unit 2B × {suction superheat degree of second outdoor unit 2B / (suction superheat degree of first outdoor unit 2A + suction superheat degree of second outdoor unit 2B + third Outdoor unit 2C suction superheat degree)} × 3
(Iii) Command opening θ2 of the control valve of the third outdoor unit 2C =
α3 × current control valve opening degree of third outdoor unit 2C × {intake superheat degree of third outdoor unit 2C / (intake superheat degree of first outdoor unit 2A + intake superheat degree of second outdoor unit 2B + third Outdoor unit 2C suction superheat degree)} × 3
Here, α1, α2, and α3 described above are adjustment values, and are arbitrary values of 0.7 to 1.3. In this case, α1, α2, and α3 can be set to arbitrary values from 0.8 to 1.2 as necessary. Furthermore, it can be set to an arbitrary value from 0.9 to 1.1. Since the outdoor units 2A, 2B, and 2C have the same capacity, α1, α2, and α3 are set to 1, respectively.

(Other)
The present invention is not limited to the embodiments described above and shown in the drawings, and can be implemented with appropriate modifications within the scope not departing from the gist. The number of outdoor units is not limited to two, but may be three or four. It is not limited to the number of indoor units. Although applied to the air conditioner which operates with the compressor 22 driven with the gas engine 20, you may apply not only to this but with the air conditioner which operates with the compressor 22 driven with a motor.

  The present invention can be used for an air conditioner having a heating function.

It is a block diagram which shows the relationship with the outdoor unit and indoor unit of an air conditioning apparatus concerning embodiment. It is a circuit diagram which shows the relationship with the outdoor unit and indoor unit of an air conditioning apparatus. It is a circuit diagram which shows the temperature sensor and pressure sensor vicinity of the outdoor unit of an air conditioning apparatus. It is a flowchart of the control which the control part of an air conditioning apparatus performs. It is a Mollier diagram. It is a block diagram which shows a control part typically. It is a block diagram which shows the relationship with the outdoor unit and indoor unit of an air conditioning apparatus concerning other embodiment.

  In the figure, 1A and 1B are indoor units, 2A and 2B are outdoor units, 3 is a refrigerant piping system, 4A and 4B are control units, 20 is an engine (drive source), 22 is a compressor (compression unit), and 23 is outdoor heat. Exchangers, 24A and 24B are sensors (detecting means), and 25 is an electronic regulating valve (control valve).

Claims (5)

A plurality or a single indoor unit that performs air conditioning, a plurality of outdoor units that supply refrigerant to the indoor unit, a refrigerant piping system that connects each outdoor unit and each indoor unit, and operation of the outdoor unit are controlled. And a control unit,
Each of the outdoor units includes a compressor having a suction port for sucking refrigerant and a discharge port for discharging compressed refrigerant, a drive source for driving the compressor, an outdoor heat exchanger connected to the compressor, and a heating operation of the indoor unit a control valve opening which serves as an expansion valve at a variable heating operation to control the flow rate of refrigerant flowing from at Oite evaporator to become the indoor unit to the outdoor heat exchanger, and said suction port of said compressor An accumulator provided between the outdoor heat exchanger and returning the refrigerant from the outdoor heat exchanger during heating operation and sending the refrigerant to the intake port of the compressor by driving the compressor; and the accumulator and the compressor The accumulator is provided between the suction port and the compressor by driving the compressor. From over motor is provided with a temperature sensor for sensing the suction temperature of the refrigerant sucked into the suction port of said compressor,
The controller is
The suction temperature detected by the temperature sensor provided between the accumulator and the suction port of the compressor, the suction superheat degree of the suction temperature of the refrigerant sucked into the suction port of the compressor of each outdoor unit Suction superheat degree calculating means to be obtained based on
When the suction superheat degree of the suction temperature of the compressor of the plurality of outdoor units is different, the opening degree of the control valve is increased for the outdoor unit having a relatively high suction superheat degree, and the suction superheat degree is relatively low. An air conditioner comprising an opening degree increasing / decreasing means for decreasing the opening degree of the control valve for the outdoor unit. In Claim 1, the said outdoor unit is a 1st outdoor unit and a 2nd outdoor unit, The said control part is command opening degree (theta) 1 of the said control valve of the said 1st outdoor unit, The said control of the said 2nd outdoor unit An air conditioner that determines a command opening θ2 of the valve based on the following equation.
(I) Command opening degree θ1 of the control valve of the first outdoor unit =
α1 × current control valve opening degree of first outdoor unit × {suction superheat degree of first outdoor unit / (suction superheat degree of first outdoor unit + suction superheat degree of second outdoor unit)} × 2
(Ii) Command opening degree θ2 of the control valve of the second outdoor unit =
α2 × current control valve opening degree of the second outdoor unit × {suction superheat degree of the second outdoor unit / (suction superheat degree of the first outdoor unit + suction superheat degree of the second outdoor unit)} × 2
Where α1 and α2 are adjustment values Te claim 1 or 2 smell, before Symbol air conditioning apparatus characterized by pressure sensor is provided for detecting the pressure of refrigerant sucked into the suction port of the compressor.   The suction superheat degree according to any one of claims 1 to 3, wherein the suction temperature of the refrigerant sucked into the suction port of the compressor is T1 (° C) and the low-pressure saturation temperature is T2 (° C). Is T1-T2 (° C.).   The air conditioner according to any one of claims 1 to 4, wherein the drive source is an engine.

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