JP2002013842A - Gas-liquid heat exchanger, and refrigerant branching unit equipped with gas-liquid heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To certainly liquid-tightly seal a refrigerant to be supplied to the inlet of a pressure reduction circuit, in a gas-liquid heat exchanger which is provided in a refrigerant circuit which includes a condenser, an evaporator, and the pressure reduction circuit. SOLUTION: This heat exchanger is equipped with an outer pipe 353 which introduces a hot refrigerant supplied from the side of a liquid pipe 33, and an inner pipe 355 which is connected just after a pressure reduction circuit and is arranged within the passage of the hot refrigerant, being laid along the bottom within the outer pipe 353, and guides a cold refrigerant supplied from the side of the pressure reduction circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided in a refrigerant circuit including a condenser, an evaporator, and a pressure reducing circuit, and exchanges heat between a high-temperature refrigerant liquid discharged from a condenser and a low-temperature refrigerant gas discharged from an evaporator. A gas-liquid heat exchanger and an outdoor heat exchanger provided in the outdoor unit and functioning as a condenser during cooling operation, and an indoor heat exchanger provided in the indoor unit and functioning as an evaporator during cooling operation, The present invention relates to a branch unit of an air conditioner that distributes refrigerant to an indoor heat exchanger of an indoor unit.

[0002]

2. Description of the Related Art In a multi-type air conditioner configured to connect a plurality of indoor units to one outdoor unit, an outdoor heat exchanger provided in the outdoor unit and an indoor heat exchanger provided in the indoor unit are provided. In the refrigerant circuit including the exchanger, it is necessary to configure a branch for performing refrigerant distribution.

During the cooling operation, the outdoor heat exchanger functions as a condenser for condensing the high-temperature and high-pressure refrigerant discharged from the compressor, and the indoor heat exchanger functions as an evaporator for evaporating the low-temperature refrigerant liquid. The outdoor heat exchanger is connected to a decompression circuit composed of an electric expansion valve and the like, and decompresses the high-temperature child pressure refrigerant supplied from the outdoor heat exchanger and supplies the refrigerant to the indoor heat exchanger as a low-temperature refrigerant liquid.

[0004]

In the air conditioner at the time of the cooling operation, the refrigerant in the refrigerant pipe from the outdoor heat exchanger to the pressure reducing circuit is in a liquid / gas mixed state depending on the amount of the charged refrigerant, the circuit design, the operation state, and the like. The two-phase flow may be caused. When the two-phase flow refrigerant is supplied at the inlet of the pressure reducing circuit, a large amount of refrigerant passing noise is generated when the refrigerant passes through the pressure reducing circuit. Therefore, in order to reliably seal the refrigerant at the inlet of the pressure reducing circuit, a sufficient amount of refrigerant is charged,
It is conceivable that a gas-liquid heat exchanger is provided after the outdoor heat exchanger to perform liquid sealing.

In a gas-liquid heat exchanger provided in an air conditioner, generally, an outer tube through which a high-temperature refrigerant supplied from a condenser side passes, and a low-temperature refrigerant arranged in the outer tube and supplied from an evaporator side pass therethrough. And an inner tube. When such a double-tube gas-liquid heat exchanger is used, it is difficult to ensure heat exchange performance. By providing grooves or fins on the outer surface of the inner tube, it may be possible to increase the heat transfer efficiency. However, it is difficult to reduce the cost. Further, even when such a gas-liquid heat exchanger is provided in the outdoor heat exchanger, it is necessary to fill the refrigerant sufficiently at the inlet of the pressure reducing circuit to ensure the liquid sealing, which is a factor of cost increase. Becomes

In a multi-type air conditioner that operates by connecting a plurality of indoor units to one outdoor unit, a branch portion for branching a refrigerant pipe is unitized and built in a casing. A branch unit may be used. The branch portions incorporated in such a branch unit are provided with the number of indoor units connected to the decompression circuits for decompressing the high-temperature refrigerant supplied from the outdoor heat exchanger side, and the low-pressure low-temperature refrigerant from each decompression circuit is provided. It is configured to supply to the indoor heat exchanger side.

In such a branch unit, the distance from the outdoor heat exchanger may be longer to some extent depending on the place where the branch unit is installed, and there is a high possibility that the refrigerant in the middle of the piping will form a two-phase flow. Become. When the refrigerant having such a two-phase flow is introduced into the pressure reducing circuit, a large refrigerant passing sound is generated as described above. Therefore, it is necessary to liquid seal the refrigerant at the inlet of the pressure reducing circuit. In order to reliably seal the liquid at the inlet of the pressure reducing circuit by filling the refrigerant, it is necessary to fill a considerable amount of the refrigerant in accordance with the installation location of the branch unit. In order to ensure reliability, it is necessary to increase the volume of the receiver and the accumulator, and the outdoor unit increases in size and size, and it is difficult to reduce the cost.

The present invention relates to a gas-liquid heat exchanger provided in a refrigerant circuit including a condenser, an evaporator, and a pressure reducing circuit.
An object of the present invention is to make it possible to reliably seal a liquid supplied to a pressure reducing circuit inlet with a liquid, thereby reducing costs.
Further, in the present invention, the outdoor heat exchanger provided in the outdoor unit and functions as a condenser during the cooling operation, and the indoor heat exchanger provided in the indoor unit and functions as an evaporator during the cooling operation, In the branch unit of the air conditioner that distributes the refrigerant to the indoor heat exchanger of the indoor unit, it is possible to suppress the noise by reliably liquid sealing the refrigerant supplied from the outdoor heat exchanger during the cooling operation, The purpose is to reduce costs.

[0009]

A gas-liquid heat exchanger according to the present invention is a gas-liquid heat exchanger provided in a refrigerant circuit including a condenser, an evaporator, and a pressure reducing circuit. And an outer tube connected immediately before the pressure reducing circuit and into which the high-temperature refrigerant supplied from the condenser side is introduced, and between the pressure reducing circuit and the evaporator and connected immediately after the pressure reducing circuit and inside the outer tube. And an inner pipe arranged in the flow path of the high-temperature refrigerant along the bottom surface of the evaporator and guiding the low-temperature refrigerant supplied from the pressure reducing circuit to the evaporator side.

Here, a plurality of pressure reducing circuits and inner tubes may be provided corresponding to the number of connected evaporators. The branch unit of the air conditioner according to the present invention,
The indoor heat exchanger is provided between an outdoor heat exchanger provided in the outdoor unit and functioning as a condenser during cooling operation and an indoor heat exchanger provided in the indoor unit and functioning as an evaporator during cooling operation. A branch unit of an air conditioner that distributes refrigerant to exchangers, and a liquid pipe for guiding high-temperature refrigerant flowing out of the outdoor heat exchanger during cooling operation, and a branch pipe that branches from the liquid pipe by the number of indoor exchangers. Between the high-temperature refrigerant in the liquid pipe immediately before the pressure-reducing circuit and the low-temperature refrigerant in the branch pipe immediately after the pressure-reducing circuit, provided in each branch pipe and decompressing the high-temperature refrigerant in the branch pipe to make the low-temperature refrigerant. A gas-liquid heat exchanger that causes heat exchange to bring the high-temperature refrigerant in the liquid pipe into a supercooled state.

Here, the gas-liquid heat exchanger includes an outer pipe for guiding the high-temperature refrigerant supplied from the liquid pipe to the pressure reducing circuit side and a part of the branch pipe immediately after the pressure reducing circuit, and has a bottom surface inside the outer pipe. An inner pipe may be provided in the flow path of the high-temperature refrigerant liquid along the inner pipe for guiding the low-temperature refrigerant supplied from the pressure reducing circuit to the indoor heat exchanger.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Branch unit enabling connection of pair-type and multi-type] An indoor unit and an outdoor unit of a pair-type air conditioner and a multi-type air conditioner can be connected and used in any combination. The configuration of the branch unit that enables the above will be described. <Outdoor unit for pair machine + indoor unit for pair machine> Outdoor unit 1 for pair machine
FIG. 1 shows a case where a plurality of indoor units 200 for a paired device are connected to 00.

The outdoor unit 100 for a paired machine includes a compressor 101,
It includes a four-way switching valve 102, an outdoor heat exchanger 103, an electric pressure reducing valve 104, an accumulator 105, and the like. The discharge side of the compressor 101 is provided with a discharge side pressure protection switch 108 for detecting an abnormal rise in the discharge pressure, and the suction side of the compressor 101 is provided with a suction side pressure sensor 110 for detecting the suction pressure. Is provided.

On the discharge side of the compressor 101, an oil separator 107 for separating lubricating oil contained in the refrigerant and returning it to the accumulator 105 is provided. A discharge pipe thermistor 109 for detecting the temperature on the discharge side of the compressor 101 is attached to the oil separator 107. A pressure adjusting valve 113 is provided in a path connecting the outlet side of the oil separator 107 and the inlet side of the accumulator 105. Also, the outdoor unit 100 has an outside air thermistor 111 for detecting outside air temperature,
An outdoor heat exchange thermistor 112 for detecting the temperature of the outdoor heat exchanger 103 is provided.

A refrigerant pipe extending from the outdoor unit 100 to the indoor unit has a liquid pipe connection port 114 led through the electric pressure reducing valve 104 and a gas pipe connection port led through the four-way switching valve 102. And a liquid pipe closing valve 116 and a gas pipe closing valve 117 provided inside each connection port. The indoor unit 200 for a pair device includes an indoor heat exchanger 201, and the indoor heat exchanger 201
Is connected to the outdoor unit via a liquid pipe connection port 204 and a gas pipe connection port 205.

The indoor unit 200 includes a room temperature thermistor 202 for detecting the indoor temperature and an indoor heat exchange thermistor 20 for detecting the temperature of the indoor heat exchanger 201.
3 is provided. In FIG. 1, three indoor units 200 for paired units are configured to be connected, and the same parts of each indoor unit 200 are denoted by the same reference numerals.

The outdoor unit 100 for a paired device and the indoor units 200 for a plurality of paired devices are connected via a branching unit 300. The branch unit 300 includes the outdoor unit 1
The liquid pipe connection port 301 of the indoor unit 200 is connected to the outdoor liquid pipe connection port 301 connected to the liquid pipe connection port 114 of the indoor unit 200.
4, an outdoor-side gas pipe connection port 303 connected to the gas pipe connection port 115 of the outdoor unit 100, and a room connected to the gas pipe connection port 205 of the indoor unit 200. Inner gas pipe connection port 304
And The indoor side liquid pipe connection port 302 and the indoor side gas pipe connection port 304 are connected to the indoor unit 20 to be connected.
As many as zero are prepared, and here three are provided respectively. Further, a branch path is formed for branching from the outdoor-side liquid pipe connection port 301 to each indoor-side liquid pipe connection port 302, and similarly branches from the outdoor-side gas pipe connection port 303 to each indoor-side gas pipe connection port 304. A fork is formed.

A branch valve from the outdoor-side liquid pipe connection port 301 in the branch unit 300 to each indoor-side liquid pipe connection port 302 has a motor-operated valve 305 for reducing the pressure of the refrigerant passing therethrough, A liquid tube thermistor 306 for detecting the temperature of the refrigerant passing therethrough is provided.
A gas pipe thermistor 307 for detecting the temperature of the refrigerant passing through the inside of the branch path from the outdoor gas pipe connection port 303 to each indoor gas pipe connection port 304 in the branch unit 300 is provided. .

In such a configuration, the branch unit 3
Since a liquid pipe thermistor 306 for detecting the temperature of the refrigerant in the liquid pipe on the indoor unit side is provided in 00, a plurality of indoor units 200 for a paired device not having a liquid pipe temperature sensor are connected to such a branch unit 300. Even in the case, each indoor unit 2
00 can be controlled. The decompression operation on the liquid pipe side is performed by setting the decompression electric valve 104 provided in the outdoor unit 100 to a predetermined opening and adjusting the opening of the electric valve 305 provided in the branch unit 300. It is also possible to control the pressure-reducing electric valve 104 and the electric valve 305 in a combined manner.

<Outdoor Unit for Pair Unit + Indoor Unit for Multi Unit + Indoor Unit for Pair Unit> A case in which the indoor unit for multi unit 250 and the indoor unit for pair unit 200 are connected to the outdoor unit for pair unit 100 is shown in FIG. Shown in Here, a case where one multi-unit indoor unit 250 and two pair-unit indoor units 200 are connected to the pair-unit outdoor unit 100 is shown.

The configurations of the outdoor unit for paired machine 100 and the indoor unit for paired machine 200 are the same as those shown in FIG. 1, and the same reference numerals are given to the respective parts, and the description thereof will be omitted. Also, the branch unit 300 can have the same configuration as that of FIG. 1, and the description thereof is omitted. The multi-unit indoor unit 250 includes an indoor heat exchanger 251, and a refrigerant pipe connected to the indoor heat exchanger 251 is led out to the outdoor unit through a liquid pipe connection port 255 and a gas pipe connection port 256. Is done.

The indoor unit 250 includes a room temperature thermistor 252 for detecting the indoor temperature and an indoor heat exchange thermistor 25 for detecting the temperature of the indoor heat exchanger 251.
3 and a liquid tube thermistor 254 for detecting the temperature of the refrigerant passing through the liquid tube. In the case of such a configuration, it is possible to perform temperature control using any detection data of the liquid tube thermistor 254 provided in the multi-unit indoor unit 250 or the liquid tube thermistor 306 provided in the branch unit 300. Becomes possible. Further, the multi-unit indoor unit 250 can be connected to and used with the pair-unit outdoor unit 100. In addition to the example shown in FIG. 25
It is also possible to connect 0 for use.

<Multi-unit outdoor unit + pair-unit indoor unit> A plurality of pair-unit indoor units 2 with respect to the multi-unit outdoor unit 150
FIG. 3 shows a case where 00 is connected. Outdoor unit 1 for multi-machine
Reference numeral 50 includes a compressor 151, a four-way switching valve 152, an outdoor heat exchanger 153, an accumulator 155, and the like. A discharge side pressure protection switch 158 for detecting an abnormal rise in the discharge pressure is provided on the discharge side of the compressor 151, and a suction side pressure sensor 160 for detecting the suction pressure is provided on the suction side of the compressor 151. Is provided.

An oil separator 157 for separating lubricating oil contained in the refrigerant and returning it to the accumulator 155 is provided on the discharge side of the compressor 151. A discharge pipe thermistor 159 for detecting the temperature on the discharge side of the compressor 151 is attached to the oil separator 157. A pressure adjusting valve 163 is provided in a path connecting the outlet side of the oil separator 157 and the inlet side of the accumulator 155. Also, the outdoor unit 150 has an outside air thermistor 161 for detecting the outside air temperature,
An outdoor heat exchange thermistor 162 for detecting the temperature of the outdoor heat exchanger 153 is provided.

Refrigerant pipes extending from the outdoor unit 150 to the indoor unit are connected to liquid pipe connection ports 166 and 167 which are drawn out through electric pressure reducing valves 164 and 165 and the four-way switching valve 10.
2 connected to the gas pipe connection ports 168 and 169
And a liquid pipe closing valve 170 provided inside the liquid pipe connecting ports 166, 167 and a gas pipe closing valve 171 provided inside the gas pipe connecting ports 168, 169.
It has.

The indoor unit 200 for the pair machine and the indoor unit 250 for the multi machine are the same as those shown in FIGS. 1 and 2, and the description thereof will be omitted. Here, two branch units 300A and 300B are provided, and one branch unit 300A has its outdoor liquid pipe connection port 301 connected to the liquid pipe connection port 166 of the outdoor unit 150,
The outdoor gas pipe connection port 303 is the gas pipe connection port 16
8 and the other branching unit 300B is
The outdoor side liquid pipe connection port 301 is connected to the liquid pipe connection port 167 of the outdoor unit 150, and the outdoor side gas pipe connection port 303 is connected to the gas pipe connection port 169.

Each of the branch units 300A and 300B is connected to three indoor units 200 for paired devices.
A total of six indoor units for paired devices 200 are connected. In such a configuration, the temperature control can be performed using the detection data of the liquid tube thermistor 306 provided in the branching unit 300.
Even if 0 is connected to the multi-unit outdoor unit 250, the operation can be performed. Further, it is possible to connect and operate more indoor units than the connection ports provided in the multi-unit outdoor unit 150.

<Outdoor Unit for Multi Unit + Indoor Unit for Pair Unit + Indoor Unit for Multi Unit> A case where the multi unit indoor unit 250 and the pair unit indoor unit 200 are connected to the multi unit outdoor unit 150 is shown in FIG. Shown in Here, the multi-unit outdoor unit 150
In this case, one multi-unit indoor unit 250 and two pair-unit indoor units 200 are connected via the branch unit 300, and the other connection port of the multi-unit outdoor unit 150 is connected to the multi-unit indoor unit 150. 2 shows an example in which a device 250 is connected.

The multi-unit outdoor unit 150 has the same configuration as that shown in FIG. 3, and the details are omitted here. The liquid pipe connection port 166 and the gas pipe connection port 168 of the outdoor unit 150 are connected to the outdoor liquid pipe connection port 301 and the outdoor gas pipe connection port 30 of the branch unit 300.
3 are connected. In addition, the multi-unit indoor unit 250 is connected to the liquid pipe connection port 167 and the gas pipe connection port 169.
Pipe connection port 255 and gas pipe connection port 256
Is connected.

The branch unit 300 is connected to one multi-unit indoor unit 250 and two pair-unit indoor units 200. The configurations of these indoor units are the same as those shown in FIGS. 1 to 3 and their details are omitted. In this manner, by using the branch unit 300, it is possible to connect more indoor units than the number of connection ports of the multi-unit outdoor unit 150. Further, a liquid tube temperature sensor of an indoor unit necessary for controlling the multi-type air conditioner is provided by a branch unit 300.
Since the liquid tube thermistor 306 can be used as a substitute, the indoor unit 200 for a pair unit can be connected, and the indoor unit 250 for a multi-unit can be mixed and connected.

As described above, in the branch unit 300,
By providing the motor-operated valves 305 and the liquid-tube thermistors 306 for the number of connected indoor units, it is possible to perform temperature control for each indoor unit, and the outdoor units of the multi-type air conditioner and the pair-type air conditioner and Even when the indoor units are used in any combination, the operation control can be performed.

[Branch unit internal structure] Branch unit 3
FIGS. 5 and 6 show the structure of the branch portion incorporated in the 00. Inside the branch unit 300, refrigerant pipes are provided between the outdoor-side liquid pipe connection port 301, the outdoor-side gas pipe connection port 303, the indoor-side liquid pipe connection ports 302A to 302C, and the indoor-side gas pipe connection ports 304A to 304C. A branching portion for branching is configured.

The liquid pipe section 333 connected to the outdoor liquid pipe connection port 301 is introduced into the gas-liquid heat exchanger 330,
Branch pipes 332A, 332B via the liquid pipe branch part 331,
332C. Each branch pipe 332A-332
C has electric valves 305A to 305C, respectively, and is configured to be introduced into the gas-liquid heat exchanger 330 immediately after the electric valves 305A to 305C.

The connecting pipe sections 334A to 334C derived from the gas-liquid heat exchanger 330 of each of the branch pipes 332A to 332C.
Are the indoor liquid pipe connection ports 302A to 302C, respectively.
It is connected to the. Indoor side gas pipe connection port 304A-
The connection pipes 335A to 335C are connected to 304C, respectively. The connection pipes 335A to 335C are connected to the gas pipe 337 via the gas pipe branch 336. The gas pipe section 337 is connected to the outdoor gas pipe connection port 303.
It is connected to the. In addition, the liquid pipe section 333 and the gas pipe section 33
7, a pressure regulating valve 338 for performing pressure regulation.
Is provided.

Indoor-side liquid pipe connection ports 302A to 302C
And connection pipe sections 334A to 334C and 335A to 340A to 334C located near the indoor side gas pipe connection ports 304A to 304C.
335C is provided with liquid pipe thermistors 306A to 306C and gas pipe thermistors 307A to 307C for detecting the temperature of the refrigerant passing therethrough. <Gas-Liquid Heat Exchanger> The gas-liquid heat exchanger 330 has a structure as shown in FIG.

A refrigerant introduction part 351 for introducing refrigerant from the liquid pipe part 333 to the gas-liquid heat exchanger 330 during cooling operation;
An outer pipe 353 having a larger inner diameter than the liquid pipe section 333 is connected between the refrigerant outlet sections 352 for extracting the refrigerant from the gas-liquid heat exchanger 330 to the electric valves 305A to 305C. The outer tube 353 is formed of the intermediate cylindrical portion 36 having a cylindrical shape.
1 and a closing plate 3 for closing both ends of the intermediate cylindrical portion 361
62, 363. In the drawing, the refrigerant introduction part 351 is attached so as to penetrate the closing plate 362 near the bottom of the gas-liquid heat exchanger 330, and the refrigerant discharge part 352 is mounted near the bottom of the gas-liquid heat exchanger 330. It is attached so as to penetrate the closing plate 363.

The branch valves 332A to 332C are drawn out from the motor-operated valves 305A to 305C, and
-Pressure refrigerant pipe 35 for guiding the refrigerant decompressed at 305C
4A to 354C are introduced into the outer tube 353 of the gas-liquid heat exchanger 330, and are connected to the inner tube portions 355A to 355C. The inner pipe sections 355A to 355C are
On the opposite side of 4A-354C, it is led out of the gas-liquid heat exchanger 330, and is connected to the connection pipe sections 334A-334C.

The inner pipe portions 355A to 355C are connected to the outer pipe 353.
And is introduced into the intermediate cylindrical portion 361 through the closing plates 362 and 363, and as shown in FIG.
It is arranged along the bottom of the inner wall of the intermediate cylinder 361. In the branching unit 300 thus configured,
During the cooling operation, the high-temperature refrigerant supplied from the outdoor heat exchanger is supplied via the liquid pipe section 333. This high-temperature refrigerant is supplied from the refrigerant introduction portion 351 to the outer tube 3 of the gas-liquid heat exchanger 330.
The refrigerant is supplied to the inside of the motor 53 and is discharged to the electric valves 305A to 305C through the refrigerant outlet 352 and the liquid pipe branch 331.

The refrigerant decompressed by the motor-operated valves 305A to 305C is supplied to the inner pipes 355A to 355C of the gas-liquid heat exchanger 330 via the decompressed refrigerant pipes 354A to 354C, and connected to the connection pipes 334A to 334C. Derived to the side. The high-temperature refrigerant supplied from the refrigerant introduction part 351 of the liquid pipe part 333 into the outer pipe 353 of the gas-liquid heat exchanger 330 exchanges heat with the decompressed low-temperature refrigerant inside the inner pipe parts 355A to 355C, thereby causing excess heat. It is in a cooling state and is drawn out from the coolant drawing-out section 352.

Here, the refrigerant introduction part 351 and the refrigerant discharge part 352 are attached near the bottoms of the closing plates 362 and 363, respectively.
It can be efficiently guided to the side of ３０５305C. Also,
Since the inner pipe portions 355A to 355C are provided along the bottom portion of the inner wall of the outer pipe 353, the refrigerant passing from the refrigerant introduction portion 351 toward the refrigerant outlet portion 352 is supplied to the inner pipe portions 355A to 355C.
Heat is efficiently exchanged with the reduced-pressure low-temperature refrigerant passing through the inside by contacting with the outer surface of the 355C.

Thus, even when the refrigerant supplied from the outdoor heat exchanger to the liquid pipe section 333 has a two-phase flow, the outer pipe 353 and the inner pipe of the gas-liquid heat exchanger 330 By exchanging heat with the portions 355A to 355C, the liquid outlet portions 352 and the inlet portions of the electric valves 305A to 305C can be reliably liquid-sealed. Therefore,
It is possible to prevent the generation of excessive passage noise due to the refrigerant passing through the electric valves 305A to 305C.

[Transmission Information Between Outdoor Unit and Branch Unit] FIG. 9 shows a control block diagram of the outdoor unit and the branch unit. Here, it is assumed that a multi-unit outdoor unit is used as the outdoor unit. The outdoor unit 150 includes an outdoor control unit 181 including a microprocessor, a ROM, a RAM, various interfaces, and the like.

The outdoor controller 181 is connected to various sensors such as a discharge side pressure protection switch 158, a discharge pipe thermistor 159, a suction side pressure sensor 160, an outside air thermistor 161, and an outdoor heat exchange thermistor 162. A signal is input. The outdoor control section 181 is configured to control each section during operation by supplying control signals to the connected compressor 151, four-way switching valve 152, pressure regulating valve 163, and the like.

The branch unit 300 includes a branch unit control unit 371 including a microprocessor, ROM, RAM, various interfaces, and the like, similar to the outdoor unit 150. A plurality of liquid pipe thermistors 306 and gas pipe thermistors 307 are connected to the branch unit control unit 371 in accordance with the number of indoor units connected to the branch unit 300, and are configured to input detection signals of the respective sensors. Have been.

The branch unit control section 371 is connected to a plurality of motor-operated valves 305 provided according to the number of indoor units connected to the branch unit 300.
A control signal is transmitted to each of the electronic devices 05 to adjust the opening. A transmission line 400 is provided between the outdoor control unit 181 and the branch unit control unit 371, and various data can be input / output via the transmission line 400. Also, a branch unit control unit 371,
A transmission line is also provided between each of the plurality of indoor units connected to the branching unit 300, and various data can be input / output to / from the indoor unit.

The outdoor controller 181 controls the air conditioning operation by controlling the operating frequency of the compressor 151 according to various conditions during operation. The branch unit control unit 371 controls the air-conditioning operation by controlling the opening pulse of the electric valve 305 according to various conditions during operation. FIG. 10 shows the relationship between the operating frequency supplied to the compressor 151 and the amount of refrigerant circulating in the refrigerant circuit. Also,
FIG. 11 shows the relationship between the opening pulse supplied to the electric valve 305 in the branch unit 300 and the air flow rate at that time.

Outdoor control unit 181 and branch unit control unit 3
When data relating to the operating frequency of the compressor 151 is transmitted / received to / from the controller 71, the refrigerant circulation amount corresponding to the operating frequency is calculated and transmitted. Also,
When data relating to the opening pulse of the electric valve 305 is transmitted and received between the outdoor control unit 181 and the branch unit control unit 371, an air flow rate according to the opening pulse is transmitted. Accordingly, even when the outdoor unit and the branch unit are combined with different models, it is possible to specify the operation amount of the electric valve 305 according to the refrigerant circulation amount and the air flow rate. The degree of freedom increases.

Outdoor control unit 181 and branch unit control unit 3
An example in which the refrigerant circulation amount and the air flow rate of the motor-operated valve are input / output as control data between the controller 71 and the controller 71 to control the motor-operated valve 305 will be described below. <Optimization of the degree of subcooling at the outlet of each indoor heat exchanger during heating operation>
During the heating operation, the degree of subcooling at the outlet of each indoor heat exchanger (S
Control logic performed in the branching unit 300 to optimize C) will be described with reference to the flowchart of FIG.

In step S1, the temperature of each indoor heat exchanger is obtained from the connected indoor unit, and its maximum value DCMXT
Ask for. In step S2, the refrigerant circulation amount QCOMP transmitted from the outdoor control unit 181 is obtained. In step S3, a target SC1 of the degree of subcooling of the indoor heat exchange outlet is obtained using the refrigerant circulation amount QCOMP obtained in step S2. Here, when determining the target SC, if the coefficient relating to the refrigerant circulation amount QCOMP is KSC1 and the offset value at the time of determining the target SC is KSC2, then SC1 = KSC1 * QCOMP-KSC2.

In step S4, the deviation SC between the target indoor heat exchange subcooling degree SC1 and the actual indoor heat exchange subcooling degree is determined. Here, SC = (| DCMXT-DL |) -SC1. Here, DL is a liquid pipe temperature detected by the liquid pipe thermistor, and the detected temperature of the liquid pipe thermistor 306 provided in the branch unit 300 can be used. When the liquid tube thermistor is provided in the indoor unit, the liquid tube temperature detected by the liquid tube thermistor can be used.

In step S5, the degree of subcooling of indoor heat exchange (S
The change flow rate QRSC of the electric valve 305 required to control C) is obtained. Here, among the PID control parameters for determining the amount of change of the electrically operated valve using the deviation between the target SC and the actual SC, the coefficient of the P control unit is KPWS, and the coefficient of the I control unit is KIWS. Assuming that the previous value of the deviation of SC is SCZ, QRSC = KPWS * ((SC-SCZ) + KIWS * (SC + SC
Z)). However, when QRSC ≤ QHENWS, QRSC = QHENWS (QHENWS: the lower limit of the change flow rate (minus value)).

In step S6, the target flow rate QAMK of the electric valve 305 is corrected. Here, it can be obtained as QAMK = QAMK + QRSC. <Optimization of refrigerant distribution amount during cooling operation> Control logic for optimizing the refrigerant distribution amount to each branch unit during the cooling operation will be described with reference to the flowchart of FIG. Here, a case where two branch units are connected to the multi-unit outdoor unit will be considered.

In step S11, among the indoor units connected to the branch unit, the MIN value of the intermediate heat exchange temperature of the operating indoor unit is obtained for each branch unit and is set as DC1MINU and DC2MINU, respectively. Step S12
Then, among the indoor units connected to the branch unit, the MIN value of the gas pipe temperature of the operating indoor unit is obtained for each branch unit and is set as DG1MINU and DG2MINU, respectively.

In step S13, the average value of the MIN value of the indoor heat exchange intermediate temperature and the average value of the MIN value of the gas pipe temperature are calculated to be DCMINAV and DGMINAV, respectively. Step S1
In step 4, the difference between the MIN value of each indoor heat exchange intermediate temperature and the MIN value average of the indoor heat exchange intermediate temperatures is calculated for each branch unit, and these are defined as ΔDC1MIN and ΔDC2MIN. ΔDC1MI
N, ΔDC2MIN can be calculated by ΔDC1MIN = DC1MINU−DCMINAV ΔDC2MIN = DC2MINU−DCMINAV.

In step S15, the difference between the MIN value of the gas pipe temperature of each indoor unit and the average value of the MIN values of the gas pipe temperatures is calculated for each branch unit, and is calculated as ΔDG1MIN, ΔDG1MIN,
DG2MIN. DerutaDG1MIN, calculation of ΔDG2MIN can be determined by _{ΔDG 1MIN = DG 1MINU -DG MINAV ΔDG} 2MIN = DG 2MINU -DG MINAV.

In step S16, the indoor heat exchange intermediate temperature difference
ΔDC_MINAnd gas pipe temperature difference ΔDG_MINFinding the difference with this
Are ΔDCG1 and ΔDCG2. ΔDCG1 = ΔDC_1MIN-ΔDG_1MIN ΔDCG2 = ΔDC_2MIN-ΔDG_2MIN In step S17, the first branch unit is placed indoors.
Heat exchange intermediate temperature difference ΔDC _1MINAnd gas pipe temperature difference ΔDG_1MINWhen
Is the predetermined value ΔDCG_MINWhether or not
Is determined. ΔDCG1 <ΔDCG_MINIf
Shifts to step S18.

In step S18, the first branch unit
Of the motor-operated valve_RDG1Is determined by the following equation. Q_RDG1= -K_GT* ΔDCG1 where K_GTIs the coefficient related to the deviation during gas pipe isothermal control.
You. In step S19, the second branch unit is
Indoor heat exchange intermediate temperature difference ΔDC _2MINAnd gas pipe temperature difference ΔDG
_2MINIs the predetermined value ΔDCG_MINIs below
It is determined whether or not. ΔDCG2 <ΔDCG_MINPlace that is
In this case, the process moves to step S20.

[0058] At step S20, determines a manipulated variable Q _{RD G2} of the electric valve by the following equation with respect to the second branch unit 300. In Q _RDG2 = -K _GT * ΔDCG2 step S21, based on the electric valve operation amount Q _RDG transmitted from the outdoor control unit 181, the branch unit control section 3
71 calculates the operation amount Q _AMK of the electric valve 305. Here, the operation amount Q _AMK of the electric valve 305 can be calculated by the following equation.

Q _AMK = Q _AMK + Q _RDG [Transmission Translation Function] FIG. 14 shows a functional block diagram of the branch unit control unit provided in the branch unit. The branch unit control unit 371 includes a microprocessor, RO
M, RAM, a microcomputer chip including various interfaces, etc., obtains various data from the outdoor control unit in the outdoor unit and the indoor control unit in the indoor unit, controls the motorized valves in the unit, and controls the outdoor control. Data transfer between the unit and the indoor control unit.

The branch unit control section 371 includes a central processing section 501 for executing various arithmetic processing. The central processing unit 501 is connected to a data acquisition unit 502 that acquires sensor data and other control data from the outdoor control unit and the indoor control unit. The data acquisition unit 502 also acquires data on the model of the outdoor unit and the indoor unit transmitted from the connected outdoor control unit and indoor control unit.

As a result of performing calculations based on various data obtained by the data acquisition unit 502, the motor-operated valve control unit 503 that transmits a control signal for the motor-operated valve and controls the opening of the motor-operated valve is controlled by the central processing unit 501. It is connected to the. The central processing unit 501 is connected to a data transmission unit 505 that transmits sensor data, control data, and the like to an outdoor control unit provided in the outdoor unit and an indoor control unit provided in the indoor unit.

The central processing unit 501 is further connected to a translation table 504 based on the models of the indoor unit and the outdoor unit. This translation table 504 is used, for example, to convert data into usable data signals when the connected outdoor unit and indoor unit use data signals having different specifications. For example, when the data specification of the thermo signal transmitted between the commercial air conditioner and the residential air conditioner is different, or when the data specifications of various signals are different due to the new and old models, the data is stored in the translation table 504 as a conversion table. Keep it.

The thermo signal transmitted from the indoor unit is
This is the difference between the room temperature detected by the room temperature thermistor and the target temperature, and the data specifications used may differ depending on the model. For example, FIG. 15 shows an example of a thermo-signal translation table when a thermo signal transmitted from a commercial indoor unit is a ΔTr signal and a thermo signal transmitted from a residential indoor unit is a ΔD signal.

When the outdoor unit connected to the branch unit is for business use and the indoor unit is for residential use, the outdoor unit is connected to the thermoelectric signal ΔD signal transmitted from the indoor unit. Thermo signal ΔTr for business machine corresponding to
The signal is converted to a signal and transmitted to the outdoor unit. Conversely, if the outdoor unit connected to the branching unit is for residential use and the indoor unit is for business use, the thermo signal ΔTr signal transmitted from the indoor unit is converted to the thermoelectric signal for the residential unit. Signal Δ
D to be transmitted to the outdoor unit.

In the case where other data has different data specifications due to the difference of the model, it can be appropriately converted by storing it in the translation table 504. In the case where the data specifications used for the air conditioners connectable to the branch unit are different, all the data specifications are stored in the translation table 504, so that any combination of the outdoor unit and the indoor unit can be used. Can also be handled.

Here, the description has been given of the case where the transmission translation function is provided in the branch unit incorporating the refrigerant branching portion for branching the refrigerant pipe from the outdoor unit to the plurality of indoor units. The same configuration can be applied to the case of a relay unit that is provided between machines and relays a refrigerant pipe and a transmission line.

[0067]

According to the present invention, in a gas-liquid heat exchanger provided in a refrigerant circuit including a condenser, an evaporator, and a pressure reducing circuit, it is possible to reliably seal the liquid supplied to the inlet of the pressure reducing circuit. In addition, it is possible to reduce the cost, and it is possible to prevent the generation of noise when the refrigerant passes through the branch unit of the air conditioner including the gas-liquid heat exchanger.

[Brief description of the drawings]

FIG. 1 is a configuration diagram in a case where an outdoor unit for a pair device and an indoor unit for a pair device are connected.

FIG. 2 is a configuration diagram in a case where an outdoor unit for a paired machine, an indoor unit for a paired machine, and an indoor unit for a multi-machine are connected.

FIG. 3 is a configuration diagram when a multi-unit outdoor unit and a pair-unit indoor unit are connected.

FIG. 4 is a configuration diagram in a case where an outdoor unit for a multi-unit, an indoor unit for a pair unit, and an indoor unit for a multi-unit are connected.

FIG. 5 is an explanatory diagram showing an internal configuration of a branch unit.

FIG. 6 is a perspective view of a refrigerant branch.

FIG. 7 is a longitudinal sectional view of the gas-liquid heat exchanger.

FIG. 8 is an explanatory sectional view of a gas-liquid heat exchanger.

FIG. 9 is a block diagram showing a schematic configuration of an outdoor unit and a branch unit.

FIG. 10 is a characteristic diagram showing a relationship between a compressor operating frequency and a refrigerant circulation amount.

FIG. 11 is a characteristic diagram showing a relationship between an opening pulse of an electric valve and an air flow rate.

FIG. 12 is a flowchart illustrating an example of electric valve control.

FIG. 13 is a flowchart illustrating an example of electric valve control.

FIG. 14 is a functional block diagram of a branch unit control unit.

FIG. 15 is an explanatory diagram showing an example of a translation table.

[Explanation of symbols]

 300 Branch unit 305 Electric valve 306 Liquid pipe thermistor 307 Gas pipe thermistor 330 Gas-liquid heat exchanger 332 Branch pipe 333 Liquid pipe section

Claims (4)

[Claims] 1. A condenser, an evaporator, and a pressure reducing circuit (305).
Gas-liquid heat exchanger (330) provided in a refrigerant circuit including
An outer pipe (353) connected between the condenser and the pressure reducing circuit (305) and immediately before the pressure reducing circuit (305), and into which the high-temperature refrigerant supplied from the condenser side is introduced; The high-temperature refrigerant is connected between the decompression circuit (305) and the evaporator immediately after the decompression circuit (305), and along the bottom surface in the outer pipe (353). And an inner pipe (355) for guiding the low-temperature refrigerant supplied from the pressure reducing circuit (305) to the evaporator side.
And a gas-liquid heat exchanger comprising: 2. The pressure reducing circuit (305) and the inner pipe (35).
The gas-liquid heat exchanger according to claim 1, wherein a plurality of (5) are provided corresponding to the number of connected evaporators. 3. A plurality of outdoor heat exchangers provided in the outdoor unit and functioning as a condenser during a cooling operation, and a plurality of indoor heat exchangers provided in the indoor unit and functioning as an evaporator during a cooling operation. A branch unit of an air conditioner that distributes refrigerant to an indoor heat exchanger of an indoor unit, wherein the liquid tube (333) guides high-temperature refrigerant flowing out of the outdoor heat exchanger during a cooling operation; (333) branch pipes (332) branching by the number of the indoor exchangers; and branch pipes (332) provided in the respective branch pipes (332).
2) a decompression circuit (305) that decompresses the high-temperature refrigerant in the refrigerant to make a low-temperature refrigerant; a high-temperature refrigerant in the liquid pipe (333) immediately before the decompression circuit (305) and a branch pipe immediately after the decompression circuit (305) (355)
A gas-liquid heat exchanger (330) for exchanging heat with a low-temperature refrigerant in the liquid tube to make the high-temperature refrigerant in the liquid tube in a supercooled state. 4. The gas-liquid heat exchanger (330) converts the high-temperature refrigerant supplied from the liquid pipe (333) into the pressure reducing circuit (3).
05) and a portion of the branch pipe (332) immediately after the pressure reducing circuit (305), and the high-temperature refrigerant in a state along the bottom surface inside the outer pipe (353). 4. The air conditioner according to claim 3, further comprising: an inner pipe (355) that is arranged in a liquid flow path and guides the low-temperature refrigerant supplied from the pressure reduction circuit (305) to the indoor heat exchanger. 5. Branch unit.